Excess S-adenosylmethionine reroutes phosphatidylethanolamine towards phosphatidylcholine and triglyceride synthesis

PubMed Central

Martínez-Uña, Maite; Varela-Rey, Marta; Cano, Ainara; Fernández-Ares, Larraitz; Beraza, Naiara; Aurrekoetxea, Igor; Martínez-Arranz, Ibon; García-Rodríguez, Juan L; Buqué, Xabier; Mestre, Daniela; Luka, Zigmund; Wagner, Conrad; Alonso, Cristina; Finnell, Richard H; Lu, Shelly C; Martínez-Chantar, M Luz; Aspichueta, Patricia; Mato, José M

2013-01-01

Methionine adenosyltransferase 1A (MAT1A) and glycine N-methyltransferase (GNMT) are the primary genes involved in hepatic S-adenosylmethionine (SAMe) synthesis and degradation, respectively. Mat1a ablation in mice induces a decrease in hepatic SAMe, activation of lipogenesis, inhibition of triglyceride (TG) release, and steatosis. Gnmt deficient mice, despite showing a large increase in hepatic SAMe, also develop steatosis. We hypothesized that as an adaptive response to hepatic SAMe accumulation, phosphatidylcholine (PC) synthesis via the phosphatidylethanolamine (PE) N-methyltransferase (PEMT) pathway is stimulated in Gnmt−/− mice. We also propose that the excess PC thus generated is catabolized leading to TG synthesis and steatosis via diglyceride (DG) generation. We observed that Gnmt−/− mice present with normal hepatic lipogenesis and increased TG release. We also observed that the flux from PE to PC is stimulated in the liver of Gnmt−/− mice and that this results in a reduction in PE content and a marked increase in DG and TG. Conversely, reduction of hepatic SAMe following the administration of a methionine deficient diet reverted the flux from PE to PC of Gnmt−/− mice to that of wild type animals and normalized DG and TG content preventing the development of steatosis. Gnmt−/− mice with an additional deletion of perilipin2, the predominant lipid droplet protein, maintain high SAMe levels, with a concurrent increased flux from PE to PC, but do not develop liver steatosis. Conclusion These findings indicate that excess SAMe reroutes PE towards PC and TG synthesis, and lipid sequestration. PMID:23505042

Validity Study of a Jump Mat Compared to the Reference Standard Force Plate.

PubMed

Rogan, Slavko; Radlinger, Lorenz; Imhasly, Caroline; Kneubuehler, Andrea; Hilfiker, Roger

2015-12-01

In the field of vertical jump diagnostics, force plates (FP) are the reference standard. Recently, despite a lack of evidence, jump mats have been used increasingly. Important factors in favor of jumping mats are their low cost and portability. This validity study compared the Haynl-Elektronik jump mat (HE jump mat) with the reference standard force plate. Ten healthy volunteers participated and each participant completed three series of five drop jumps (DJ). The parameters ground contact time (GCT) and vertical jump height (VJH) from the HE jump mat and the FP were used to evaluate the concurrent validity. The following statistical calculations were performed: Pearson's correlation (r), Bland-Altman plots (standard and for adjusted trend), and regression equations. The Bland-Altman plots suggest that the HE jump mat measures shorter contact times and higher jump heights than the FP. The trend-adjusted Bland-Altman plot shows higher mean differences and wider wing-spreads of confidence limits during longer GCT. During the VJH the mean differences and the wing-spreads of the confidence limits throughout the range present as relatively constant. The following regression equations were created, as close as possible to the true value: GCT = 5.920385 + 1.072293 × [value HE jump mat] and VJH = -1.73777 + 1.011156 × [value HE jump mat]. The HE jump mat can be recommended in relation to the validity of constraints. In this study, only a part of the quality criteria were examined. For the final recommendation it is advised to examine the HE jump mat on the other quality criteria (test-retest reliability, sensitivity change).

Ectopic Expression of Retrotransposon-Derived PEG11/RTL1 Contributes to the Callipyge Muscular Hypertrophy

PubMed Central

Xu, Xuewen; Ectors, Fabien; Davis, Erica E.; Pirottin, Dimitri; Cheng, Huijun; Farnir, Frédéric; Hadfield, Tracy; Cockett, Noelle; Charlier, Carole; Georges, Michel; Takeda, Haruko

2015-01-01

The callipyge phenotype is an ovine muscular hypertrophy characterized by polar overdominance: only heterozygous + Mat /CLPG Pat animals receiving the CLPG mutation from their father express the phenotype. + Mat /CLPG Pat animals are characterized by postnatal, ectopic expression of Delta-like 1 homologue (DLK1) and Paternally expressed gene 11/Retrotransposon-like 1 (PEG11/RTL1) proteins in skeletal muscle. We showed previously in transgenic mice that ectopic expression of DLK1 alone induces a muscular hypertrophy, hence demonstrating a role for DLK1 in determining the callipyge hypertrophy. We herein describe newly generated transgenic mice that ectopically express PEG11 in skeletal muscle, and show that they also exhibit a muscular hypertrophy phenotype. Our data suggest that both DLK1 and PEG11 act together in causing the muscular hypertrophy of callipyge sheep. PMID:26474044

Role of estrogen receptor signaling in skeletal response to leptin in female ob/ob mice.

PubMed

Turner, Russell T; Philbrick, Kenneth A; Kuah, Amida F; Branscum, Adam J; Iwaniec, Urszula T

2017-06-01

Leptin, critical in regulation of energy metabolism, is also important for normal bone growth, maturation and turnover. Compared to wild type (WT) mice, bone mass is lower in leptin-deficient ob/ob mice. Osteopenia in growing ob/ob mice is due to decreased bone accrual, and is associated with reduced longitudinal bone growth, impaired cancellous bone maturation and increased marrow adipose tissue (MAT). However, leptin deficiency also results in gonadal dysfunction, disrupting production of gonadal hormones which regulate bone growth and turnover. The present study evaluated the role of increased estrogen in mediating the effects of leptin on bone in ob/ob mice. Three-month-old female ob/ob mice were randomized into one of the 3 groups: (1) ob/ob  + vehicle (veh), (2) ob/ob  + leptin (leptin) or (3) ob/ob  + leptin and the potent estrogen receptor antagonist ICI 182,780 (leptin + ICI). Age-matched WT mice received vehicle. Leptin (40 µg/mouse, daily) and ICI (10 µg/mouse, 2×/week) were administered by subcutaneous injection for 1 month and bone analyzed by X-ray absorptiometry, microcomputed tomography and static and dynamic histomorphometry. Uterine weight did not differ between ob/ob mice and ob/ob mice receiving leptin + ICI, indicating that ICI successfully blocked the uterine response to leptin-induced increases in estrogen levels. Compared to leptin-treated ob/ob mice, ob/ob mice receiving leptin + ICI had lower uterine weight; did not differ in weight loss, MAT or bone formation rate; and had higher longitudinal bone growth rate and cancellous bone volume fraction. We conclude that increased estrogen signaling following leptin treatment is dispensable for the positive actions of leptin on bone and may attenuate leptin-induced bone growth. © 2017 Society for Endocrinology.

Molecular Diversity of Cyanobacteria Inhabiting Coniform Structures and Surrounding Mat in a Yellowstone Hot Spring

NASA Astrophysics Data System (ADS)

Lau, Evan; Nash, Cody Z.; Vogler, Detlev R.; Cullings, K. W.

2005-02-01

Lithified coniform structures are common within cyanobacterial mats in Yellowstone National Park hot springs. It is unknown whether these structures and the mats from which they develop are inhabited by the same cyanobacterial populations. Denaturing gradient gel electrophoresis and sequencing and phylogenetic analysis of 16S rDNA was used to determine whether (1) three different morphological types of lithified coniform structures are inhabited by different cyanobacterial species, (2) these species are partitioned along a vertical gradient of these structures, and (3) lithified and non-lithified sections of mat are inhabited by different cyanobacterial species. Our results, based on multiple samplings, indicate that the cyanobacterial community compositions in the three lithified morphological types were identical and lacked any vertical differentiation. However, lithified and non-lithified portions of the same mat were inhabited by distinct and different populations of cyanobacteria. Cyanobacteria inhabiting lithified structures included at least one undefined Oscillatorialean taxon, which may represent the dominant cyanobacteria genus in lithified coniform stromatolites, Phormidium, three Synechococcus-like species, and two unknown cyanobacterial taxa. In contrast, the surrounding mats contained four closely related Synechococcus-like species. Our results indicate that the distribution of lithified coniform stromatolites may be dependent on the presence of one or more microorganisms, which are phylogenetically different from those inhabiting surrounding non-lithified mats.

Lycopene and Apo-10′-lycopenoic Acid Have Differential Mechanisms of Protection against Hepatic Steatosis in β-Carotene-9′,10′-oxygenase Knockout Male Mice123

PubMed Central

Ip, Blanche C; Liu, Chun; Lichtenstein, Alice H; von Lintig, Johannes; Wang, Xiang-Dong

2015-01-01

Background: Nonalcoholic fatty liver disease is positively associated with obesity and cardiovascular disease risk. Apo-10′-lycopenoic acid (APO10LA), a potential oxidation product of apo-10′-lycopenal that is generated endogenously by β-carotene-9′,10′-oxygenase (BCO2) cleavage of lycopene, inhibited hepatic steatosis in BCO2-expressing mice. Objective: The present study evaluated lycopene and APO10LA effects on hepatic steatosis in mice without BCO2 expression. Methods: Male and female BCO2-knockout (BCO2-KO) mice were fed a high saturated fat diet (HSFD) with or without APO10LA (10 mg/kg diet) or lycopene (100 mg/kg diet) for 12 wk. Results: Lycopene or APO10LA supplementation reduced hepatic steatosis incidence (78% and 72%, respectively) and severity in BCO2-KO male mice. Female mice did not develop steatosis, had greater hepatic total cholesterol (3.06 vs. 2.31 mg/g tissue) and cholesteryl ester (1.58 vs. 0.86 mg/g tissue), but had lower plasma triglyceride (TG) (229 vs. 282 mg/dL) and cholesterol (97.1 vs. 119 mg/dL) than male mice. APO10LA-mitigated steatosis in males was associated with reduced hepatic total cholesterol (18%) and activated sirtuin 1 signaling, which resulted in reduced fatty acids (FAs) and TG synthesis markers [stearoyl-coenzyme A (CoA) desaturase protein, 71%; acetyl-CoA carboxylase phosphorylation, 79%; AMP-activated protein kinase phosphorylation, 67%], and elevated cholesterol efflux genes (cytochrome P450 family 7A1, 65%; ATP-binding cassette transporter G5/8, 11%). These APO10LA-mediated effects were not mimicked by lycopene supplementation. Intriguingly, steatosis inhibition by lycopene induced peroxisome proliferator–activated receptor (PPAR)α- and PPARγ-related genes in mesenteric adipose tissue (MAT) that increases mitochondrial uncoupling [cell death–inducing DNA fragmentation factor, α subunit-like effector a, 55%; PR domain-containing 16, 47%; uncoupling protein 3 (Ucp3), 55%], FA β-oxidation (PPARα, 53%; very long chain acyl-CoA dehydrogenase, 38%), and uptake (FA transport protein 4, 29%; lipoprotein lipase 43%). Expressions of 10 MAT PPAR-related genes were inversely correlated with steatosis score, suggesting that lycopene reduced steatosis by increasing MAT FA utilization. Conclusions: Our data suggest that lycopene and APO10LA inhibit HSFD-induced steatosis in BCO2-KO male mice through differential mechanisms. Sex disparity of BCO2-KO mice was observed in the outcomes of HSFD-induced liver steatosis and plasma lipids. PMID:25644347

HLA Haplotype Frequency Estimation from Real-Life Data with the Hapl-o-Mat Software.

PubMed

Sauter, Jürgen; Schäfer, Christian; Schmidt, Alexander H

2018-01-01

HLA haplotype frequencies are of use in a variety of settings. Such data is typically derived either from family pedigree data by targeted typing or statistical analysis of large population-specific genotype samples. As established tools for the latter approach lacked ability to treat the amount, ambiguity, and inhomogeneity found in genotype data in hematopoietic stem cell donor registries, we developed Hapl-o-Mat to alleviate these specific shortcomings.

Marrow Adipose Tissue in Older Men: Association with Visceral and Subcutaneous Fat, Bone Volume, Metabolism, and Inflammation.

PubMed

Bani Hassan, Ebrahim; Demontiero, Oddom; Vogrin, Sara; Ng, Alvin; Duque, Gustavo

2018-03-26

Marrow (MAT) and subcutaneous (SAT) adipose tissues display different metabolic profiles and varying associations with aging, bone density, and fracture risk. Using a non-invasive imaging methodology, we aimed to investigate the associations between MAT, SAT, and visceral fat (VAT) with bone volume, bone remodeling markers, insulin resistance, and circulating inflammatory mediators in a population of older men. In this cross-sectional study, 96 healthy men (mean age 67 ± 5.5) were assessed for anthropometric parameters, body composition, serum biochemistry, and inflammatory panel. Using single-energy computed tomography images, MAT (in L2 and L3 and both hips), VAT, and SAT (at the level of L2-L3 and L4-L5) were measured employing Slice-O-Matic software (Tomovision), which enables specific tissue demarcation applying previously reported Hounsfield unit thresholds. MAT volume was similar in all anatomical sites and independent of BMI. In all femoral regions of interest (ROIs) there was a strong negative association between bone and MAT volumes (r = - 0.840 to - 0.972, p < 0.001), with location-dependent variations in the lumbar spine. Unlike VAT and SAT, no associations between MAT and serum glucose, inflammatory markers or insulin resistance indicators were found. Bone decline occurred without red marrow expansion; thus lost bone was mainly (if not exclusively) replaced by MAT. In conclusion, strong inverse correlations between MAT and bone mass, which have been previously observed in women, were also confirmed in older men. However, MAT volume in all ROIs was interrelated and unlike women, mainly independent of VAT or SAT. The lack of strong association between MAT vs VAT/SAT, and its discordant associations with metabolic and inflammatory mediators provide further evidence on MAT's distinct attributes in older men.

RESPIRATORY TOXICOLOGCAL EFFECTS OF WORLD TRADE CENTER FINE PARTICULATE MATTER IN MICE

EPA Science Inventory

ABSTRACT BODY:
The destruction of the World Trade Center (WTC) caused the release of high levels of airborne pollutants which were reported to cause adverse respiratory responses in rescue workers and nearby residents. We examined whether WTC-derived fine particulate mat...

Lava Cave Microbial Communities Within Mats and Secondary Mineral Deposits: Implications for Life Detection on Other Planets

PubMed Central

Melim, L.A.; Spilde, M.N.; Hathaway, J.J.M.; Garcia, M.G.; Moya, M.; Stone, F.D.; Boston, P.J.; Dapkevicius, M.L.N.E.; Riquelme, C.

2011-01-01

Abstract Lava caves contain a wealth of yellow, white, pink, tan, and gold-colored microbial mats; but in addition to these clearly biological mats, there are many secondary mineral deposits that are nonbiological in appearance. Secondary mineral deposits examined include an amorphous copper-silicate deposit (Hawai‘i) that is blue-green in color and contains reticulated and fuzzy filament morphologies. In the Azores, lava tubes contain iron-oxide formations, a soft ooze-like coating, and pink hexagons on basaltic glass, while gold-colored deposits are found in lava caves in New Mexico and Hawai‘i. A combination of scanning electron microscopy (SEM) and molecular techniques was used to analyze these communities. Molecular analyses of the microbial mats and secondary mineral deposits revealed a community that contains 14 phyla of bacteria across three locations: the Azores, New Mexico, and Hawai‘i. Similarities exist between bacterial phyla found in microbial mats and secondary minerals, but marked differences also occur, such as the lack of Actinobacteria in two-thirds of the secondary mineral deposits. The discovery that such deposits contain abundant life can help guide our detection of life on extraterrestrial bodies. Key Words: Biosignatures—Astrobiology—Bacteria—Caves—Life detection—Microbial mats. Astrobiology 11, 601–618. PMID:21879833

Subunit association as the stabilizing determinant for archaeal methionine adenosyltransferases.

PubMed

Garrido, Francisco; Alfonso, Carlos; Taylor, John C; Markham, George D; Pajares, María A

2009-07-01

Archaea contain a class of methionine adenosyltransferases (MATs) that exhibit substantially higher stability than their mesophilic counterparts. Their sequences are highly divergent, but preserve the essential active site motifs of the family. We have investigated the origin of this increased stability using chemical denaturation experiments on Methanococcus jannaschii MAT (Mj-MAT) and mutants containing single tryptophans in place of tyrosine residues. The results from fluorescence, circular dichroism, hydrodynamic, and enzyme activity measurements showed that the higher stability of Mj-MAT derives largely from a tighter association of its subunits in the dimer. Local fluorescence changes, interpreted using secondary structure predictions, further identify the least stable structural elements as the C-terminal ends of beta-strands E2 and E6, and the N-terminus of E3. Dimer dissociation however requires a wider perturbation of the molecule. Additional analysis was initially hindered by the lack of crystal structures for archaeal MATs, a limitation that we overcame by construction of a 3D-homology model of Mj-MAT. This model predicts preservation of the chain topology and three-domain organization typical of this family, locates the least stable structural elements at the flat contact surface between monomers, and shows that alterations in all three domains are required for dimer dissociation.

Lava cave microbial communities within mats and secondary mineral deposits: implications for life detection on other planets.

PubMed

Northup, D E; Melim, L A; Spilde, M N; Hathaway, J J M; Garcia, M G; Moya, M; Stone, F D; Boston, P J; Dapkevicius, M L N E; Riquelme, C

2011-09-01

Lava caves contain a wealth of yellow, white, pink, tan, and gold-colored microbial mats; but in addition to these clearly biological mats, there are many secondary mineral deposits that are nonbiological in appearance. Secondary mineral deposits examined include an amorphous copper-silicate deposit (Hawai'i) that is blue-green in color and contains reticulated and fuzzy filament morphologies. In the Azores, lava tubes contain iron-oxide formations, a soft ooze-like coating, and pink hexagons on basaltic glass, while gold-colored deposits are found in lava caves in New Mexico and Hawai'i. A combination of scanning electron microscopy (SEM) and molecular techniques was used to analyze these communities. Molecular analyses of the microbial mats and secondary mineral deposits revealed a community that contains 14 phyla of bacteria across three locations: the Azores, New Mexico, and Hawai'i. Similarities exist between bacterial phyla found in microbial mats and secondary minerals, but marked differences also occur, such as the lack of Actinobacteria in two-thirds of the secondary mineral deposits. The discovery that such deposits contain abundant life can help guide our detection of life on extraterrestrial bodies.

Phototrophs in high-iron-concentration microbial mats: physiological ecology of phototrophs in an iron-depositing hot spring

NASA Technical Reports Server (NTRS)

Pierson, B. K.; Parenteau, M. N.; Griffin, B. M.

1999-01-01

At Chocolate Pots Hot Springs in Yellowstone National Park the source waters have a pH near neutral, contain high concentrations of reduced iron, and lack sulfide. An iron formation that is associated with cyanobacterial mats is actively deposited. The uptake of [(14)C]bicarbonate was used to assess the impact of ferrous iron on photosynthesis in this environment. Photoautotrophy in some of the mats was stimulated by ferrous iron (1.0 mM). Microelectrodes were used to determine the impact of photosynthetic activity on the oxygen content and the pH in the mat and sediment microenvironments. Photosynthesis increased the oxygen concentration to 200% of air saturation levels in the top millimeter of the mats. The oxygen concentration decreased with depth and in the dark. Light-dependent increases in pH were observed. The penetration of light in the mats and in the sediments was determined. Visible radiation was rapidly attenuated in the top 2 mm of the iron-rich mats. Near-infrared radiation penetrated deeper. Iron was totally oxidized in the top few millimeters, but reduced iron was detected at greater depths. By increasing the pH and the oxygen concentration in the surface sediments, the cyanobacteria could potentially increase the rate of iron oxidation in situ. This high-iron-content hot spring provides a suitable model for studying the interactions of microbial photosynthesis and iron deposition and the role of photosynthesis in microbial iron cycling. This model may help clarify the potential role of photosynthesis in the deposition of Precambrian banded iron formations.

Trehalose-Based Block Copolycations Promote Polyplex Stabilization for Lyophilization and in Vivo pDNA Delivery

PubMed Central

2015-01-01

The development and thorough characterization of nonviral delivery agents for nucleic acid and genome editing therapies are of high interest to the field of nanomedicine. Indeed, this vehicle class offers the ability to tune chemical architecture/biological activity and readily package nucleic acids of various sizes and morphologies for a variety of applications. Herein, we present the synthesis and characterization of a class of trehalose-based block copolycations designed to stabilize polyplex formulations for lyophilization and in vivo administration. A 6-methacrylamido-6-deoxy trehalose (MAT) monomer was synthesized from trehalose and polymerized via reversible addition–fragmentation chain transfer (RAFT) polymerization to yield pMAT43. The pMAT43 macro-chain transfer agent was then chain-extended with aminoethylmethacrylamide (AEMA) to yield three different pMAT-b-AEMA cationic-block copolymers, pMAT-b-AEMA-1 (21 AEMA repeats), -2 (44 AEMA repeats), and -3 (57 AEMA repeats). These polymers along with a series of controls were used to form polyplexes with plasmids encoding firefly luciferase behind a strong ubiquitous promoter. The trehalose-coated polyplexes were characterized in detail and found to be resistant to colloidal aggregation in culture media containing salt and serum. The trehalose-polyplexes also retained colloidal stability and promoted high gene expression following lyophilization and reconstitution. Cytotoxicity, cellular uptake, and transfection ability were assessed in vitro using both human glioblastoma (U87) and human liver carcinoma (HepG2) cell lines wherein pMAT-b-AEMA-2 was found to have the optimal combination of high gene expression and low toxicity. pMAT-b-AEMA-2 polyplexes were evaluated in mice via slow tail vein infusion. The vehicle displayed minimal toxicity and discouraged nonspecific internalization in the liver, kidney, spleen, and lungs as determined by quantitative polymerase chain reaction (qPCR) and fluorescence imaging experiments. Hydrodynamic infusion of the polyplexes, however, led to very specific localization of the polyplexes to the mouse liver and promoted excellent gene expression in vivo. PMID:26807438

Long-term fermented soybean paste improves metabolic parameters associated with non-alcoholic fatty liver disease and insulin resistance in high-fat diet-induced obese mice.

PubMed

Kim, Min-Seok; Kim, Bobae; Park, Haryung; Ji, Yosep; Holzapfel, Wilhelm; Kim, Do-Young; Hyun, Chang-Kee

2018-01-08

Recently, Korean traditional fermented soybean paste, called Doenjang, has attracted attention for its protective effect against diet-related chronic diseases such as obesity and type 2 diabetes. Long-term fermented soybean pastes (LFSPs) are made by fermentation with naturally-occurring microorganisms for several months, whereas short-term fermented soybean pastes (SFSPs) are produced by shorter-time fermentation inoculated with a starter culture. Here, we demonstrate that administration of LFSP, but not SFSP, protects high-fat diet (HFD)-fed obese mice against non-alcohol fatty liver disease (NAFLD) and insulin resistance. LFSP suppressed body weight gain in parallel with reduction in fat accumulation in mesenteric adipose tissue (MAT) and the liver via modulation of MAT lipolysis and hepatic lipid uptake. LFSP-treated mice also had improved glucose tolerance and increased adiponectin levels concomitantly with enhanced AMPK activation in skeletal muscle and suppressed expression of pro-inflammatory cytokines in skeletal muscle and the liver. LFSP also attenuated HFD-induced gut permeability and lowered serum lipopolysaccharide level, providing an evidence for its probiotic effects, which was supported by the observation that treatment of a probiotic mixture of LFSP-originated Bacillus strains protected mice against HFD-induced adiposity and glucose intolerance. Our findings suggest that the intake of LFSP, but not SFSP, offers protection against NAFLD and insulin resistance, which is an effect of long-term fermentation resulting in elevated contents of active ingredients (especially flavonoids) and higher diversity and richness of Bacillus probiotic strains compared to SFSP. Copyright © 2017 Elsevier Inc. All rights reserved.

DNA barcoding of invasive plants in China: A resource for identifying invasive plants.

PubMed

Xu, Song-Zhi; Li, Zhen-Yu; Jin, Xiao-Hua

2018-01-01

Invasive plants have aroused attention globally for causing ecological damage and having a negative impact on the economy and human health. However, it can be extremely challenging to rapidly and accurately identify invasive plants based on morphology because they are an assemblage of many different families and many plant materials lack sufficient diagnostic characteristics during border inspections. It is therefore urgent to evaluate candidate loci and build a reliable genetic library to prevent invasive plants from entering China. In this study, five common single markers (ITS, ITS2, matK, rbcL and trnH-psbA) were evaluated using 634 species (including 469 invasive plant species in China, 10 new records to China, 16 potentially invasive plant species around the world but not introduced into China yet and 139 plant species native to China) based on three different methods. Our results indicated that ITS2 displayed largest intra- and interspecific divergence (1.72% and 91.46%). Based on NJ tree method, ITS2, ITS, matK, rbcL and trnH-psbA provided 76.84%, 76.5%, 63.21%, 52.86% and 50.68% discrimination rates, respectively. The combination of ITS + matK performed best and provided 91.03% discriminatory power, followed by ITS2 + matK (85.78%). For identifying unknown individuals, ITS + matK had 100% correct identification rate based on our database, followed by ITS/ITS2 (both 93.33%) and ITS2 + matK (91.67%). Thus, we propose ITS/ITS2 + matK as the most suitable barcode for invasive plants in China. This study also demonstrated that DNA barcoding is an efficient tool for identifying invasive species. © 2017 John Wiley & Sons Ltd.

Fruiting Body Formation in Volvariella volvacea Can Occur Independently of Its MAT-A-Controlled Bipolar Mating System, Enabling Homothallic and Heterothallic Life Cycles.

PubMed

Chen, Bingzhi; van Peer, Arend F; Yan, Junjie; Li, Xiao; Xie, Bin; Miao, Juan; Huang, Qianhui; Zhang, Lei; Wang, Wei; Fu, Junsheng; Zhang, Xiang; Zhang, Xiaoyin; Hu, Fengli; Kong, Qingfang; Sun, Xianyun; Zou, Feng; Zhang, Hanxing; Li, Shaojie; Xie, Baogui

2016-07-07

Volvariella volvacea is an important crop in Southeast Asia, but erratic fruiting presents a serious challenge for its production and breeding. Efforts to explain inconsistent fruiting have been complicated by the multinucleate nature, typical lack of clamp connections, and an incompletely identified sexual reproductive system. In this study, we addressed the life cycle of V. volvacea using whole genome sequencing, cloning of MAT loci, karyotyping of spores, and fruiting assays. Microscopy analysis of spores had previously indicated the possible coexistence of heterothallic and homothallic life cycles. Our analysis of the MAT loci showed that only MAT-A, and not MAT-B, controlled heterokaryotization. Thus, the heterothallic life cycle was bipolar. Karyotyping of single spore isolates (SSIs) using molecular markers supported the existence of heterokaryotic spores. However, most SSIs were clearly not heterokaryotic, yet contained structural variation (SV) markers relating to both alleles of both parents. Heterokaryons from crossed, self-sterile homokaryons could produce fruiting bodies, agreeing with bipolar heterothallism. Meanwhile, some SSIs with two different MAT-A loci also produced fruiting bodies, which supported secondary homothallism. Next, SSIs that clearly contained only one MAT-A locus (homothallism) were also able to fruit, demonstrating that self-fertile SSIs were not, per definition, secondary homothallic, and that a third life cycle or genetic mechanism must exist. Finally, recombination between SV markers was normal, yet 10 out of 24 SV markers showed 1:2 or 1:3 distributions in the spores, and large numbers of SSIs contained doubled SV markers. This indicated selfish genes, and possibly partial aneuploidy. Copyright © 2016 Chen et al.

Honey/Chitosan Nanofiber Wound Dressing Enriched with Allium sativum and Cleome droserifolia: Enhanced Antimicrobial and Wound Healing Activity.

PubMed

Sarhan, Wessam A; Azzazy, Hassan M E; El-Sherbiny, Ibrahim M

2016-03-01

Two natural extracts were loaded within fabricated honey, poly(vinyl alcohol), chitosan nanofibers (HPCS) to develop biocompatible antimicrobial nanofibrous wound dressing. The dried aqueous extract of Cleome droserifolia (CE) and Allium sativum aqueous extract (AE) and their combination were loaded within the HPCS nanofibers in the HPCS-CE, HPCS-AE, and HPCS-AE/CE nanofiber mats, respectively. It was observed that the addition of AE resulted in the least fiber diameter (145 nm), whereas the addition of the AE and CE combination resulted in the least swelling ability and the highest weight loss. In vitro antibacterial testing against Staphylococcus aureus, Escherichia coli, Methicillin-resistant S. aureus (MRSA), and multidrug-resistant Pseudomonas aeruginosa was performed in comparison with the commercial dressing AquacelAg and revealed that the HPCS-AE and HPCS-AE/CE nanofiber mats allowed complete inhibition of S. aureus and the HPCS-AE/CE exhibited mild antibacterial activity against MRSA. A preliminary in vivo study revealed that the developed nanofiber mats enhanced the wound healing process as compared to the untreated control as proved by the enhanced wound closure rates in mice and by the histological examination of the wounds. Moreover, comparison with the commercial dressing Aquacel Ag, the HPCS, and HPCS-AE/CE demonstrated similar effects on the wound healing process, whereas the HPCS/AE allowed an enhanced wound closure rate. Cell culture studies proved the biocompatibility of the developed nanofiber mats in comparison with the commercial Aquacel Ag, which exhibited noticeable cytotoxicity. The developed natural nanofiber mats hold potential as promising biocompatible antibacterial wound dressing.

New strategy for the survey of Toxoplasma gondii in meat for human consumption.

PubMed

Villena, Isabelle; Durand, Benoit; Aubert, Dominique; Blaga, Radu; Geers, Régine; Thomas, Myriam; Perret, Catherine; Alliot, Annie; Escotte-Binet, Sandie; Thébault, Anne; Boireau, Pascal; Halos, Lénaïg

2012-02-10

Monitoring of Toxoplasma infection in animals destined for human consumption is a great challenge for human toxoplasmosis prevention. This study aimed to compare results obtained from a naturally infected population of sheep using different tests and targeting an original matrix: meat samples and muscle fluids collected at the slaughterhouse. A commercial ELISA test was performed on diaphragm fluids from 419 ovine carcasses collected at the slaughterhouse. A MAT (modified agglutination test) was performed on heart fluids obtained from the same animals. In addition, all hearts were bioassayed in mice. Serological test agreement, the relative sensitivity of ELISA MAT and mouse bioassay as well as a correlation between titres and parasite isolation probability were statistically evaluated. The overall agreement (kappa coefficient=0.64) of ELISA on diaphragm fluids and MAT on heart fluids is substantial and subsequently both tests can be used for epidemiological studies. Relative sensitivity was higher for MAT performed on cardiac fluids (90%) than ELISA on diaphragm fluid (61%). For both serological tests, relative sensitivity is lower in lambs younger than 12 months. Relative sensitivity of mouse inoculation was 42%. A significant correlation was obtained between increasing MAT titres and probability to isolate live parasite from the heart. When the fluid titre was higher than 1:16, parasites were isolated in 65% of cases. When it was lower, isolation failed in 95% of the cases. According to our results, cardiac fluids appear to be a relevant matrix for toxoplasmosis survey in meat. Copyright © 2011 Elsevier B.V. All rights reserved.

Assessment of mangroves from Goa, west coast India using DNA barcode.

PubMed

Saddhe, Ankush Ashok; Jamdade, Rahul Arvind; Kumar, Kundan

2016-01-01

Mangroves are salt-tolerant forest ecosystems of tropical and subtropical intertidal regions. They are among most productive, diverse, biologically important ecosystem and inclined toward threatened system. Identification of mangrove species is of critical importance in conserving and utilizing biodiversity, which apparently hindered by a lack of taxonomic expertise. In recent years, DNA barcoding using plastid markers rbcL and matK has been suggested as an effective method to enrich traditional taxonomic expertise for rapid species identification and biodiversity inventories. In the present study, we performed assessment of available 14 mangrove species of Goa, west coast India based on core DNA barcode markers, rbcL and matK. PCR amplification success rate, intra- and inter-specific genetic distance variation and the correct identification percentage were taken into account to assess candidate barcode regions. PCR and sequence success rate were high in rbcL (97.7 %) and matK (95.5 %) region. The two candidate chloroplast barcoding regions (rbcL, matK) yielded barcode gaps. Our results clearly demonstrated that matK locus assigned highest correct identification rates (72.09 %) based on TaxonDNA Best Match criteria. The concatenated rbcL + matK loci were able to adequately discriminate all mangrove genera and species to some extent except those in Rhizophora, Sonneratia and Avicennia. Our study provides the first endorsement of the species resolution among mangroves using plastid genes with few exceptions. Our future work will be focused on evaluation of other barcode markers to delineate complete resolution of mangrove species and identification of putative hybrids.

Niebla ceruchis from Laguna Figueroa: dimorphic spore morphology and secondary compounds localized in pycnidia and apothecia

NASA Technical Reports Server (NTRS)

Enzien, M.; Margulis, L.

1988-01-01

During and after the floods of 1979-80 Niebla ceruchis growing epiphytically on Lycium brevipes was one of the dominant aspects of the vegetation in the coastal dunal complex bordering the microbial mats at Laguna Figueroa, Baja California Norte, Mexico. The lichen on denuded branches of Lycium was far more extensively distributed than Lycium lacking lichen. Unusual traits of this Niebla ceruchis strain, namely localization of lichen compounds in the mycobiont reproductive structures (pycnidia and apothecia) and simultaneous presence of bilocular and quadrilocular ascospores, are reported. The abundance of this coastal lichen cover at the microbial mat site has persisted through April 1988.

Isolation and genetic characterization of Toxoplasma gondii from alpaca (Vicugna pacos) and sheep (Ovis aries) grazed on pasture in Virginia

USDA-ARS?s Scientific Manuscript database

Muscles (heart, skeletal muscle) of nine alpacas with MAT titers of 1:25 were fed to T. gondii-free cats; the cats did not shed oocysts. Viable T. gondii was isolated from tissues of two of six seropositive alpacas by bioassay in mice. Viable T. gondii was isolated from three of three seropositive s...

Quantitative Ultrasound Comparison of MAT and 4T1 Mammary Tumors in Mice and Rats Across Multiple Imaging Systems.

PubMed

Wirtzfeld, Lauren A; Ghoshal, Goutam; Rosado-Mendez, Ivan M; Nam, Kibo; Park, Yeonjoo; Pawlicki, Alexander D; Miller, Rita J; Simpson, Douglas G; Zagzebski, James A; Oelze, Michael L; Hall, Timothy J; O'Brien, William D

2015-08-01

Quantitative ultrasound estimates such as the frequency-dependent backscatter coefficient (BSC) have the potential to enhance noninvasive tissue characterization and to identify tumors better than traditional B-mode imaging. Thus, investigating system independence of BSC estimates from multiple imaging platforms is important for assessing their capabilities to detect tissue differences. Mouse and rat mammary tumor models, 4T1 and MAT, respectively, were used in a comparative experiment using 3 imaging systems (Siemens, Ultrasonix, and VisualSonics) with 5 different transducers covering a range of ultrasonic frequencies. Functional analysis of variance of the MAT and 4T1 BSC-versus-frequency curves revealed statistically significant differences between the two tumor types. Variations also were found among results from different transducers, attributable to frequency range effects. At 3 to 8 MHz, tumor BSC functions using different systems showed no differences between tumor type, but at 10 to 20 MHz, there were differences between 4T1 and MAT tumors. Fitting an average spline model to the combined BSC estimates (3-22 MHz) demonstrated that the BSC differences between tumors increased with increasing frequency, with the greatest separation above 15 MHz. Confining the analysis to larger tumors resulted in better discrimination over a wider bandwidth. Confining the comparison to higher ultrasonic frequencies or larger tumor sizes allowed for separation of BSC-versus-frequency curves from 4T1 and MAT tumors. These constraints ensure that a greater fraction of the backscattered signals originated from within the tumor, thus demonstrating that statistically significant tumor differences were detected. © 2015 by the American Institute of Ultrasound in Medicine.

Analysis of changes in hepatic gene expression in a murine model of tolerance to acetaminophen hepatotoxicity (autoprotection)

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Connor, Meeghan A., E-mail: meeghan.oconnor@boehringer-ingelheim.com; Boehringer Ingelheim Pharmaceuticals Inc., 900 Ridgebury Road, Ridgefield, CT 06877-0368; Koza-Taylor, Petra, E-mail: petra.h.koza-taylor@pfizer.com

Pretreatment of mice with a low hepatotoxic dose of acetaminophen (APAP) results in resistance to a subsequent, higher dose of APAP. This mouse model, termed APAP autoprotection was used here to identify differentially expressed genes and cellular pathways that could contribute to this development of resistance to hepatotoxicity. Male C57BL/6J mice were pretreated with APAP (400 mg/kg) and then challenged 48 h later with 600 mg APAP/kg. Livers were obtained 4 or 24 h later and total hepatic RNA was isolated and hybridized to Affymetrix Mouse Genome MU430{sub 2} GeneChip. Statistically significant genes were determined and gene expression changes weremore » also interrogated using the Causal Reasoning Engine (CRE). Extensive literature review narrowed our focus to methionine adenosyl transferase-1 alpha (MAT1A), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), flavin-containing monooxygenase 3 (Fmo3) and galectin-3 (Lgals3). Down-regulation of MAT1A could lead to decreases in S-adenosylmethionine (SAMe), which is known to protect against APAP toxicity. Nrf2 activation is expected to play a role in protective adaptation. Up-regulation of Lgals3, one of the genes supporting the Nrf2 hypothesis, can lead to suppression of apoptosis and reduced mitochondrial dysfunction. Fmo3 induction suggests the involvement of an enzyme not known to metabolize APAP in the development of tolerance to APAP toxicity. Subsequent quantitative RT-PCR and immunochemical analysis confirmed the differential expression of some of these genes in the APAP autoprotection model. In conclusion, our genomics strategy identified cellular pathways that might further explain the molecular basis for APAP autoprotection. - Highlights: • Differential expression of genes in mice resistant to acetaminophen hepatotoxicity. • Increased gene expression of Flavin-containing monooxygenase 3 and Galectin-3. • Decrease in MAT1A expression and compensatory hepatocellular regeneration. • Two distinct gene expression patterns support contrasting Nrf2 responses. • Genomics identification of pathways relevant to resistance to APAP hepatotoxicity.« less

Design and Performance of an Enhanced Bioremediation Pilot Test in a Tidal Wetland Seep, West Branch Canal Creek, Aberdeen Proving Ground, Maryland

USGS Publications Warehouse

Majcher, Emily H.; Lorah, Michelle M.; Phelan, Daniel J.; McGinty, Angela L.

2009-01-01

Because of a lack of available in situ remediation methods for sensitive wetland environments where contaminated groundwater discharges, the U.S. Geological Survey, in cooperation with the U.S. Army Garrison, Aberdeen Proving Ground, Maryland, conceived, designed, and pilot tested a permeable reactive mat that can be placed horizontally at the groundwater/surface-water interface. Development of the reactive mat was part of an enhanced bioremediation study in a tidal wetland area along West Branch Canal Creek at Aberdeen Proving Ground, where localized areas of preferential discharge (seeps) transport groundwater contaminated with carbon tetrachloride, chloroform, tetrachloroethene, trichloroethene, and 1,1,2,2-tetrachloroethane from the Canal Creek aquifer to land surface. The reactive mat consisted of a mixture of commercially available organic- and nutrient-rich peat and compost that was bioaugmented with a dechlorinating microbial consortium, WBC-2, developed for this study. Due to elevated chlorinated methane concentrations in the pilot test site, a layer of zero-valent iron mixed with the peat and compost was added at the base of the reactive mat to promote simultaneous abiotic and biotic degradation. The reactive mat for the pilot test area was designed to optimize chlorinated volatile organic compound degradation efficiency without altering the geotechnical and hydraulic characteristics, or creating undesirable water quality in the surrounding wetland area, which is referred to in this report as achieving geotechnical, hydraulic, and water-quality compatibility. Optimization of degradation efficiency was achieved through the selection of a sustainable organic reactive matrix, electron donor, and bioaugmentation method. Consideration of geotechnical compatibility through design calculations of bearing capacity, settlement, and geotextile selection showed that a 2- to 3-feet tolerable thickness of the mat was possible, with 0.17 feet settlement predicted for unconsolidated sediments between 1.5 and 6 years following installation of the reactive mat. To ensure hydraulic compatibility in the mat design, mat materials that had a hydraulic conductivity greater than the surrounding wetland sediments were selected, and the mixture was optimized to consist of 1.5 parts compost, 1.5 parts peat and 1 part sand as a safeguard against fluidization. Sediment and matrix properties also indicated that a nonwoven geotextile with a cross-plane flow greater than that of the native sediments was suitable as the base of the reactive mat. Another nonwoven geotextile was selected for installation between the iron mix and organic zones of the mat to create more laminar flow conditions within the mat. Total metals and sequential extraction procedure analyses of mat materials, which were conducted to evaluate water-quality compatibility of the mat materials, showed that concentrations of metals in the compost ranged from one-half to one order of magnitude below consensus-based probable effect concentrations in sediment. A 22-inch-thick reactive mat, containing 0.5 percent WBC-2 by volume, was constructed at seep area 3-4W and monitored from October 2004 through October 2005 for the pilot test. No local, immediate failure of the mat or of wetland sediments was observed during mat installation, indicating that design estimates of bearing capacity and geotextile textile selection ensured the integrity of the mat and wetland sediments during and following installation. Measurements of surface elevation of the mat showed an average settlement of the mat surface of approximately 0.25 feet after 10 months, which was near the predicted settlement for unconsolidated sediment. Monitoring showed rapid establishment and sustainment throughout the year of methanogenic conditions conducive to anaerobic biodegradation and efficient dechlorination activity by WBC-2. The median mass removal of chloromethanes and total chloroethenes and ethane during the

Genetic and biologic characteristics of Toxoplasma gondii isolates in free-range chickens from Colombia, South America.

PubMed

Dubey, J P; Gomez-Marin, Jorge E; Bedoya, Angela; Lora, Fabiana; Vianna, M C B; Hill, D; Kwok, O C H; Shen, S K; Marcet, P L; Lehmann, T

2005-11-25

The prevalence of Toxoplasma gondii in free-ranging chickens is a good indicator of the prevalence of T. gondii oocysts in the soil because chickens feed from the ground. The prevalence of T. gondii in 77 free-range chickens (Gallus domesticus) from Colombia, South America was determined. Antibodies to T. gondii were assayed by the modified agglutination test (MAT), and found in 32 (44.4%) of 72 chickens with titers of 1:5 in 4, 1:10 in 3, 1:20 in 1, 1:40 in 1, 1:80 in 8, 1:160 in 8, 1:320 in 3, and 1:640 or higher in 4. Hearts and brains of 31 seropositive chickens were pooled and bioassayed in mice. Tissues from 32 (16+16) seronegative chickens were pooled and fed to two, T. gondii-free cats, and tissues from nine chickens without matching sera were fed to one T. gondii-free cat. Feces of cats were examined for oocysts. T. gondii oocysts were excreted by a cat that was fed tissues of 16 seronegative chickens. T. gondii was isolated by bioassay in mice from 23 chickens with MAT titers of 1:20 or higher. All infected mice from 16 of the 23 isolates died of toxoplasmosis. Overall, 82 (81.1%) of 101 mice that became infected after inoculation with chicken tissues died of toxoplasmosis. Genotyping of these 24 isolates using polymorphisms at the SAG2 locus indicated that seven T. gondii isolates were Type I, 17 were Type III, and none was Type II. Phenotypically, T. gondii isolates from chickens from Colombia were similar to isolates from Brazil but different from the isolates from North America; most isolates from chickens from Brazil and Colombia were lethal for mice whereas isolates from North America did not kill inoculated mice. Genetically, none of the T. gondii isolates from Colombia and Brazil was SAG2 Type II, whereas most isolates from chickens from North America were Type II. This is the first report of genetic characterization of T. gondii isolates from Colombia, South America.

Leaf litter decomposition rates increase with rising mean annual temperature in Hawaiian tropical montane wet forests

PubMed Central

Bothwell, Lori D.; Giardina, Christian P.; Litton, Creighton M.

2014-01-01

Decomposing litter in forest ecosystems supplies nutrients to plants, carbon to heterotrophic soil microorganisms and is a large source of CO2 to the atmosphere. Despite its essential role in carbon and nutrient cycling, the temperature sensitivity of leaf litter decay in tropical forest ecosystems remains poorly resolved, especially in tropical montane wet forests where the warming trend may be amplified compared to tropical wet forests at lower elevations. We quantified leaf litter decomposition rates along a highly constrained 5.2 °C mean annual temperature (MAT) gradient in tropical montane wet forests on the Island of Hawaii. Dominant vegetation, substrate type and age, soil moisture, and disturbance history are all nearly constant across this gradient, allowing us to isolate the effect of rising MAT on leaf litter decomposition and nutrient release. Leaf litter decomposition rates were a positive linear function of MAT, causing the residence time of leaf litter on the forest floor to decline by ∼31 days for each 1 °C increase in MAT. Our estimate of the Q10 temperature coefficient for leaf litter decomposition was 2.17, within the commonly reported range for heterotrophic organic matter decomposition (1.5–2.5) across a broad range of ecosystems. The percentage of leaf litter nitrogen (N) remaining after six months declined linearly with increasing MAT from ∼88% of initial N at the coolest site to ∼74% at the warmest site. The lack of net N immobilization during all three litter collection periods at all MAT plots indicates that N was not limiting to leaf litter decomposition, regardless of temperature. These results suggest that leaf litter decay in tropical montane wet forests may be more sensitive to rising MAT than in tropical lowland wet forests, and that increased rates of N release from decomposing litter could delay or prevent progressive N limitation to net primary productivity with climate warming. PMID:25493213

Carbon-Isotopic Dynamics of Streams, Taylor Valley, Antarctica: Biological Effects

NASA Technical Reports Server (NTRS)

Neumann, K.; DesMarais, D. J.

1998-01-01

We have investigated the role of biological processes in the C-isotopic dynamics of the aquatic ecosystems in Taylor Valley, Antarctica. This cold desert ecosystem is characterized by the complete lack of vascular plants, and the presence of algal mats in ephemeral streams and perennially ice covered lakes. Streams having abundant algal mats and mosses have very low sigma CO2 concentrations, as well as the most depleted delta C-13 values (-4%). Previous work has shown that algal mats in these streams have delta C-13 values averaging -7.01%. These values are similar to those observed in the algal mats in shallow areas of the lakes in Taylor Valley, where CO2 is thought to be colimiting to growth. These low Sigma CO2 concentrations, and delta C(13) signatures heavier than the algal mats, suggest that CO2 may be colimiting in the streams, as well. Streams with little algal growth, especially the longer ones in Fryxell Basin, have higher Sigma CO2 concentrations and much more enriched isotopic signatures (as high as +8%). In these streams, the dissolution of isotopically enriched, cryogenic CaCO3 is probably the major source of dissolved carbonate. The delta C(13) geochemistry of Antarctic streams is radically different from the geochemistry of more temperate streams, as it is not affected by terrestrially produced, isotopically depleted Sigma CO2. These results have important implications for the understanding of "biogenic" carbonate that might have been produced from aquatic ecosystems in the past on Mars.

Functional proteomics of nonalcoholic steatohepatitis: Mitochondrial proteins as targets of S-adenosylmethionine

PubMed Central

Santamaría, Enrique; Avila, Matías A.; Latasa, M. Ujue; Rubio, Angel; Martín-Duce, Antonio; Lu, Shelly C.; Mato, José M.; Corrales, Fernando J.

2003-01-01

Recent work shows that S-adenosylmethionine (AdoMet) helps maintain normal liver function as chronic hepatic deficiency results in spontaneous development of steatohepatitis and hepatocellular carcinoma. The mechanisms by which these nontraditional functions of AdoMet occur are unknown. Here, we use knockout mice deficient in hepatic AdoMet synthesis (MAT1A−/−) to study the proteome of the liver during the development of steatohepatitis. One hundred and seventeen protein spots, differentially expressed during the development of steatohepatitis, were selected and identified by peptide mass fingerprinting. Among them, 12 proteins were found to be affected from birth, when MAT1A−/− expression is switched on in WT mouse liver, to the rise of histological lesions, which occurs at ≈8 months. Of the 12 proteins, 4 [prohibitin 1 (PHB1), cytochrome c oxidase I and II, and ATPase β-subunit] have known roles in mitochondrial function. We show that the alteration in expression of PHB1 correlates with a loss of mitochondrial function. Experiments in isolated rat hepatocytes indicate that AdoMet regulates PHB1 content, thus suggesting ways by which steatohepatitis may be induced. Importantly, we found the expression of these mitochondrial proteins was abnormal in ob/ob mice and obese patients who are at risk for nonalcoholic steatohepatitis. PMID:12631701

Fenofibrate, but not ezetimibe, prevents fatty liver disease in mice lacking phosphatidylethanolamine N-methyltransferase.

PubMed

van der Veen, Jelske N; Lingrell, Susanne; Gao, Xia; Takawale, Abhijit; Kassiri, Zamaneh; Vance, Dennis E; Jacobs, René L

2017-04-01

Mice lacking phosphatidylethanolamine N -methyltransferase (PEMT) are protected from high-fat diet (HFD)-induced obesity and insulin resistance. However, these mice develop severe nonalcoholic fatty liver disease (NAFLD) when fed the HFD, which is mainly due to inadequate secretion of VLDL particles. Our aim was to prevent NAFLD development in mice lacking PEMT. We treated Pemt -/- mice with either ezetimibe or fenofibrate to see if either could ameliorate liver disease in these mice. Ezetimibe treatment did not reduce fat accumulation in Pemt -/- livers, nor did it reduce markers for hepatic inflammation or fibrosis. Fenofibrate, conversely, completely prevented the development of NAFLD in Pemt -/- mice: hepatic lipid levels, as well as markers of endoplasmic reticulum stress, inflammation, and fibrosis, in fenofibrate-treated Pemt -/- mice were similar to those in Pemt +/+ mice. Importantly, Pemt -/- mice were still protected against HFD-induced obesity and insulin resistance. Moreover, fenofibrate partially reversed hepatic steatosis and fibrosis in Pemt -/- mice when treatment was initiated after NAFLD had already been established. Increasing hepatic fatty acid oxidation can compensate for the lower VLDL-triacylglycerol secretion rate and prevent/reverse fatty liver disease in mice lacking PEMT. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

Fenofibrate, but not ezetimibe, prevents fatty liver disease in mice lacking phosphatidylethanolamine N-methyltransferase[S

PubMed Central

van der Veen, Jelske N.; Lingrell, Susanne; Gao, Xia; Takawale, Abhijit; Kassiri, Zamaneh; Vance, Dennis E.; Jacobs, René L.

2017-01-01

Mice lacking phosphatidylethanolamine N-methyltransferase (PEMT) are protected from high-fat diet (HFD)-induced obesity and insulin resistance. However, these mice develop severe nonalcoholic fatty liver disease (NAFLD) when fed the HFD, which is mainly due to inadequate secretion of VLDL particles. Our aim was to prevent NAFLD development in mice lacking PEMT. We treated Pemt−/− mice with either ezetimibe or fenofibrate to see if either could ameliorate liver disease in these mice. Ezetimibe treatment did not reduce fat accumulation in Pemt−/− livers, nor did it reduce markers for hepatic inflammation or fibrosis. Fenofibrate, conversely, completely prevented the development of NAFLD in Pemt−/− mice: hepatic lipid levels, as well as markers of endoplasmic reticulum stress, inflammation, and fibrosis, in fenofibrate-treated Pemt−/− mice were similar to those in Pemt+/+ mice. Importantly, Pemt−/− mice were still protected against HFD-induced obesity and insulin resistance. Moreover, fenofibrate partially reversed hepatic steatosis and fibrosis in Pemt−/− mice when treatment was initiated after NAFLD had already been established. Increasing hepatic fatty acid oxidation can compensate for the lower VLDL-triacylglycerol secretion rate and prevent/reverse fatty liver disease in mice lacking PEMT. PMID:28159867

Gaillard Island Bio-degradable Geotube Test Project, Mobile Bay, Alabama

DTIC Science & Technology

2016-12-01

and strong threads and is second to cotton as one of the most affordable natural fibers produced. Jute is woven into mats and used for many...burlap is made including cotton , hemp, bamboo, and other fibrous plants; however, all these materials lack the strength of jute and are not available in

Biomarkers: d13C and d15N Distribution Tightly Coupled to Nutrient Dynamics and Viral Lysing in a Microbial Mat From Death Valley, California

NASA Astrophysics Data System (ADS)

Hewson, I.; Archer, R.; Mahaffey, C.; Scott, J.; Tsapin, A.

2002-12-01

Extrapolations into ancient biomes make many assumptions and inferences regarding life modes and environmental habitat. While definition of a stromatolite as an extinct microbial biome by petrographic analysis is promising, Life interacts with is environment, actively manipulating energy flow across chemical disequilibria gradients, harvesting energy crucial for physiological maintenance and reproduction. Such structuring of communities in turn, leaves specific chemical/isotopic imprints related to physiological processes of prokaryotic communities specific to each oxidation/redox horizon. We examine stable isotopic d13C signals (d13C and d15N) as potential biomarkers reflecting bacterial physiology and microbial community nutrient-energy dynamics. While isotopes may reveal ancient chemical structuring of microbial mats, we also turn to invoking viral lysing of bacterial hosts in nutrient cycling within modern extreme environments as well as ancient stromatic structures of early Earth. Our records of d13C indicate extreme enrichment(-12%) for Corg in our extant mat due to CO2 limitation across a hypersaline diffusive barrier at the mat's surface. d15N is lowest at the mat's surface (indicating N2- fixation) where nitrogen- fixing cyanobacteria Microcoleus sp. are present . Viruses are extremely abundant in the microbial mat, exceeding bacterial abundances by a factor of ten. The ratio of viruses to bacteria was very high (VBR = 39 ñ 10) compared with abundances in marine sediments. Distribution of viruses closely follows distribution of bacteria, suggesting bacteria as primary hosts. The ratio of viruses to bacteria is inversely correlated to the concentration of organic C suggesting virus abundance is responsive to host substrate availability. High ratios of viruses to bacteria in mid-mat horizons (2.5 - 3.7 cm) above increasing levels of d13C in deeper horizons, coupled with a lack of increase in bacteria, suggests that viral lysis contributes to significant downward organic C (polysaccaride exudates) transport within the mat. Subsequent accumulation of d13C as well as heavier d15N in deeper sediment(denitrification)horizons elucidates tight nutrient coupling between evaporite substrate, nitrogen fixing primary producers and downcore zones of active denitrification and sulphate reduction. Discrepencies between d13C of ancient stromatolites (in line with C-3 photosynthetic pathways) and modern analogues (Badwater, CA) suggest a migration of microbial mats towards more extreme environments through time. A methodology for isotopically testing environmental and physiological responses in the geological record is presented here.

Isolation and genetic characterization of Toxoplasma gondii from alpaca (Vicugna pacos) and sheep (Ovis aries).

PubMed

Dubey, Jitender Prakash; Casey, Sarah Jane; Zajac, Anne Marie; Wildeus, Stephen Arthur; Lindsay, David Scott; Verma, Shiv Kumar; Oliveira, Solange; Kwok, Oliver Chun Hung; Su, Chunlei

2014-12-01

Alpacas are important to the economy of several countries. Little is known of Toxoplasma gondii infection in alpacas worldwide. In the present study, T. gondii was isolated and genetically characterized from alpacas for the first time. Alpacas (n = 16) and rams (n = 12) pastured on a farm in Virginia, USA, were examined at necropsy. Antibodies to T. gondii were determined by the modified agglutination test (MAT, 1:25) and found in 6 of 16 alpacas with titers of 1:100 (2 alpaca), 1:400 (2 alpacas), 1:800 (1 alpaca), and 1:1,600 (1 alpaca), and 5 of 12 rams in titers of 1:50 in one, 1:400 in one, 1:800 in one, 1:1,600 in one, and 1:3,200 in one. Tissues of all 16 alpacas were bioassayed in mice or in cats. Muscles (heart, skeletal muscle) of nine alpacas with MAT titers of 1:25 were fed to T. gondii-free cats; the cats did not shed oocysts. Viable T. gondii was isolated from tissues of two of six seropositive alpacas by bioassay in mice. Viable T. gondii was isolated from three of three seropositive sheep by bioassay in mice. Genotyping using cell-cultured tachyzoites revealed four genotypes, including one for ToxoDB PCR-RFLP genotype #2 (type III), one for genotype #3 (type II variant), one for genotype #170, and two for a new genotype designated as ToxoDB PCR-RFLP genotype #230. Thus, four of the five T. gondii isolates in the present study belonged to different genotypes. These results indicate a higher genetic diversity among T. gondii isolates circulating in the USA than previously realized.

Strain-dependent dysregulation of one-carbon metabolism in male mice is associated with choline- and folate-deficient diet-induced liver injury.

PubMed

Pogribny, Igor P; Kutanzi, Kristy; Melnyk, Stepan; de Conti, Aline; Tryndyak, Volodymyr; Montgomery, Beverly; Pogribna, Marta; Muskhelishvili, Levan; Latendresse, John R; James, S Jill; Beland, Frederick A; Rusyn, Ivan

2013-06-01

Dysregulation of one-carbon metabolism-related metabolic processes is a major contributor to the pathogenesis of nonalcoholic fatty liver disease (NAFLD). It is well established that genetic and gender-specific variations in one-carbon metabolism contribute to the vulnerability to NAFLD in humans. To examine the role of one-carbon metabolism dysregulation in the pathogenesis and individual susceptibility to NAFLD, we used a "population-based" mouse model where male mice from 7 inbred were fed a choline- and folate-deficient (CFD) diet for 12 wk. Strain-dependent down-regulation of several key one-carbon metabolism genes, including methionine adenosyltransferase 1α (Mat1a), cystathionine-β-synthase (Cbs), methylenetetrahydrofolate reductase (Mthfr), adenosyl-homocysteinase (Ahcy), and methylenetetrahydrofolate dehydrogenase 1 (Mthfd1), was observed. These changes were strongly associated with interstrain variability in liver injury (steatosis, necrosis, inflammation, and activation of fibrogenesis) and hyperhomocysteinemia. Mechanistically, the decreased expression of Mat1a, Ahcy, and Mthfd1 was linked to a reduced level and promoter binding of transcription factor CCAAT/enhancer binding protein β (CEBPβ), which directly regulates their transcription. The strain specificity of diet-induced dysregulation of one-carbon metabolism suggests that interstrain variation in the regulation of one-carbon metabolism may contribute to the differential vulnerability to NFLD and that correcting the imbalance may be considered as preventive and treatment strategies for NAFLD.

Renal calcinosis and stone formation in mice lacking osteopontin, Tamm-Horsfall protein, or both.

PubMed

Mo, Lan; Liaw, Lucy; Evan, Andrew P; Sommer, Andre J; Lieske, John C; Wu, Xue-Ru

2007-12-01

Although often supersaturated with mineral salts such as calcium phosphate and calcium oxalate, normal urine possesses an innate ability to keep them from forming harmful crystals. This inhibitory activity has been attributed to the presence of urinary macromolecules, although controversies abound regarding their role, or lack thereof, in preventing renal mineralization. Here, we show that 10% of the mice lacking osteopontin (OPN) and 14.3% of the mice lacking Tamm-Horsfall protein (THP) spontaneously form interstitial deposits of calcium phosphate within the renal papillae, events never seen in wild-type mice. Lack of both proteins causes renal crystallization in 39.3% of the double-null mice. Urinalysis revealed elevated concentrations of urine phosphorus and brushite (calcium phosphate) supersaturation in THP-null and OPN/THP-double null mice, suggesting that impaired phosphorus handling may be linked to interstitial papillary calcinosis in THP- but not in OPN-null mice. In contrast, experimentally induced hyperoxaluria provokes widespread intratubular calcium oxalate crystallization and stone formation in OPN/THP-double null mice, while completely sparing the wild-type controls. Whole urine from OPN-, THP-, or double-null mice all possessed a dramatically reduced ability to inhibit the adhesion of calcium oxalate monohydrate crystals to renal epithelial cells. These data establish OPN and THP as powerful and functionally synergistic inhibitors of calcium phosphate and calcium oxalate crystallization in vivo and suggest that defects in either molecule may contribute to renal calcinosis and stone formation, an exceedingly common condition that afflicts up to 12% males and 5% females.

Neuronal serotonin regulates growth of the intestinal mucosa in mice.

PubMed

Gross, Erica R; Gershon, Michael D; Margolis, Kara G; Gertsberg, Zoya V; Li, Zhishan; Cowles, Robert A

2012-08-01

The enteric abundance of serotonin (5-HT), its ability to promote proliferation of neural precursors, and reports that 5-HT antagonists affect crypt epithelial proliferation led us to investigate whether 5-HT affects growth and maintenance of the intestinal mucosa in mice. cMice that lack the serotonin re-uptake transporter (SERTKO mice) and wild-type mice were given injections of selective serotonin re-uptake inhibitors (gain-of-function models). We also analyzed mice that lack tryptophan hydroxylase-1 (TPH1KO mice, which lack mucosal but not neuronal 5-HT) and mice deficient in tryptophan hydroxylase-2 (TPH2KO mice, which lack neuronal but not mucosal 5-HT) (loss-of-function models). Wild-type and SERTKO mice were given ketanserin (an antagonist of the 5-HT receptor, 5-HT(2A)) or scopolamine (an antagonist of the muscarinic receptor). 5-HT(2A) receptors and choline acetyltransferase were localized by immunocytochemical analysis. Growth of the mucosa and proliferation of mucosal cells were significantly greater in SERTKO mice and in mice given selective serotonin re-uptake inhibitors than in wild-type mice, but were diminished in TPH2KO (but not in TPH1KO) mice. Ketanserin and scopolamine each prevented the ability of SERT knockout or inhibition to increase mucosal growth and proliferation. Cholinergic submucosal neurons reacted with antibodies against 5-HT(2A). 5-HT promotes growth and turnover of the intestinal mucosal epithelium. Surprisingly, these processes appear to be mediated by neuronal, rather than mucosal, 5-HT. The 5-HT(2A) receptor activates cholinergic neurons, which provide a muscarinic innervation to epithelial effectors. Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.

Role of superoxide–nitric oxide interactions in the accelerated age-related loss of muscle mass in mice lacking Cu,Zn superoxide dismutase

PubMed Central

Sakellariou, Giorgos K; Pye, Deborah; Vasilaki, Aphrodite; Zibrik, Lea; Palomero, Jesus; Kabayo, Tabitha; McArdle, Francis; Van Remmen, Holly; Richardson, Arlan; Tidball, James G; McArdle, Anne; Jackson, Malcolm J

2011-01-01

Summary Mice lacking Cu,Zn superoxide dismutase (SOD1) show accelerated, age-related loss of muscle mass. Lack of SOD1 may lead to increased superoxide, reduced nitric oxide (NO), and increased peroxynitrite, each of which could initiate muscle fiber loss. Single muscle fibers from flexor digitorum brevis of wild-type (WT) and Sod1−/− mice were loaded with NO-sensitive (4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate, DAF-FM) and superoxide-sensitive (dihydroethidium, DHE) probes. Gastrocnemius muscles were analyzed for SOD enzymes, nitric oxide synthases (NOS), and 3-nitrotyrosine (3-NT) content. A lack of SOD1 did not increase superoxide availability at rest because no increase in ethidium or 2-hydroxyethidium (2-HE) formation from DHE was seen in fibers from Sod1−/− mice compared with those from WT mice. Fibers from Sod1−/− mice had decreased NO availability (decreased DAF-FM fluorescence), increased 3-NT in muscle proteins indicating increased peroxynitrite formation and increased content of peroxiredoxin V (a peroxynitrite reductase), compared with WT mice. Muscle fibers from Sod1−/− mice showed substantially reduced generation of superoxide in response to contractions compared with fibers from WT mice. Inhibition of NOS did not affect DHE oxidation in fibers from WT or Sod1−/− mice at rest or during contractions, but transgenic mice overexpressing nNOS showed increased DAF-FM fluorescence and reduced DHE oxidation in resting muscle fibers. It is concluded that formation of peroxynitrite in muscle fibers is a major effect of lack of SOD1 in Sod1−/− mice and may contribute to fiber loss in this model, and that NO regulates superoxide availability and peroxynitrite formation in muscle. PMID:21443684

Bacteria from diverse habitats colonize and compete in the mouse gut.

PubMed

Seedorf, Henning; Griffin, Nicholas W; Ridaura, Vanessa K; Reyes, Alejandro; Cheng, Jiye; Rey, Federico E; Smith, Michelle I; Simon, Gabriel M; Scheffrahn, Rudolf H; Woebken, Dagmar; Spormann, Alfred M; Van Treuren, William; Ursell, Luke K; Pirrung, Megan; Robbins-Pianka, Adam; Cantarel, Brandi L; Lombard, Vincent; Henrissat, Bernard; Knight, Rob; Gordon, Jeffrey I

2014-10-09

To study how microbes establish themselves in a mammalian gut environment, we colonized germ-free mice with microbial communities from human, zebrafish, and termite guts, human skin and tongue, soil, and estuarine microbial mats. Bacteria from these foreign environments colonized and persisted in the mouse gut; their capacity to metabolize dietary and host carbohydrates and bile acids correlated with colonization success. Cohousing mice harboring these xenomicrobiota or a mouse cecal microbiota, along with germ-free "bystanders," revealed the success of particular bacterial taxa in invading guts with established communities and empty gut habitats. Unanticipated patterns of ecological succession were observed; for example, a soil-derived bacterium dominated even in the presence of bacteria from other gut communities (zebrafish and termite), and human-derived bacteria colonized germ-free bystander mice before mouse-derived organisms. This approach can be generalized to address a variety of mechanistic questions about succession, including succession in the context of microbiota-directed therapeutics. Copyright © 2014 Elsevier Inc. All rights reserved.

Type I interferon signals in macrophages and dendritic cells control dengue virus infection: implications for a new mouse model to test dengue vaccines.

PubMed

Züst, Roland; Toh, Ying-Xiu; Valdés, Iris; Cerny, Daniela; Heinrich, Julia; Hermida, Lisset; Marcos, Ernesto; Guillén, Gerardo; Kalinke, Ulrich; Shi, Pei-Yong; Fink, Katja

2014-07-01

Dengue virus (DENV) infects an estimated 400 million people every year, causing prolonged morbidity and sometimes mortality. Development of an effective vaccine has been hampered by the lack of appropriate small animal models; mice are naturally not susceptible to DENV and only become infected if highly immunocompromised. Mouse models lacking both type I and type II interferon (IFN) receptors (AG129 mice) or the type I IFN receptor (IFNAR(-/-) mice) are susceptible to infection with mouse-adapted DENV strains but are severely impaired in mounting functional immune responses to the virus and thus are of limited use for study. Here we used conditional deletion of the type I IFN receptor (IFNAR) on individual immune cell subtypes to generate a minimally manipulated mouse model that is susceptible to DENV while retaining global immune competence. Mice lacking IFNAR expression on CD11c(+) dendritic cells and LysM(+) macrophages succumbed completely to DENV infection, while mice deficient in the receptor on either CD11c(+) or LysM(+) cells were susceptible to infection but often resolved viremia and recovered fully from infection. Conditional IFNAR mice responded with a swift and strong CD8(+) T-cell response to viral infection, compared to a weak response in IFNAR(-/-) mice. Furthermore, mice lacking IFNAR on either CD11c(+) or LysM(+) cells were also sufficiently immunocompetent to raise a protective immune response to a candidate subunit vaccine against DENV-2. These data demonstrate that mice with conditional deficiencies in expression of the IFNAR represent improved models for the study of DENV immunology and screening of vaccine candidates. Dengue virus infects 400 million people every year worldwide, causing 100 million clinically apparent infections, which can be fatal if untreated. Despite many years of research, there are no effective vaccine and no antiviral treatment available for dengue. Development of vaccines has been hampered in particular by the lack of a suitable small animal model. Mouse models used to test dengue vaccine are deficient in interferon (IFN) type I signaling and severely immunocompromised and therefore likely not ideal for the testing of vaccines. In this study, we explored alternative models lacking the IFN receptor only on certain cell types. We show that mice lacking the IFN receptor on either CD11c- or LysM-expressing cells (conditional IFNAR mice) are susceptible to dengue virus infection. Importantly, we demonstrate that conditional IFN receptor knockout mice generate a better immune response to live virus and a candidate dengue vaccine compared to IFNAR mice and are resistant to subsequent challenge. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Maintaining two mating types: structure of the mating type locus and its role in heterokaryosis in Podospora anserina.

PubMed

Grognet, Pierre; Bidard, Frédérique; Kuchly, Claire; Tong, Laetitia Chan Ho; Coppin, Evelyne; Benkhali, Jinane Ait; Couloux, Arnaud; Wincker, Patrick; Debuchy, Robert; Silar, Philippe

2014-05-01

Pseudo-homothallism is a reproductive strategy elected by some fungi producing heterokaryotic sexual spores containing genetically different but sexually compatible nuclei. This lifestyle appears as a compromise between true homothallism (self-fertility with predominant inbreeding) and complete heterothallism (with exclusive outcrossing). However, pseudohomothallic species face the problem of maintaining heterokaryotic mycelia to fully benefit from this lifestyle, as homokaryons are self-sterile. Here, we report on the structure of chromosome 1 in mat+ and mat- isolates of strain S of the pseudohomothallic fungus Podospora anserina. Chromosome 1 contains either one of the mat+ and mat- mating types of P. anserina, which is mostly found in nature as a mat+/mat- heterokaryotic mycelium harboring sexually compatible nuclei. We identified a "mat" region ∼0.8 Mb long, devoid of meiotic recombination and containing the mating-type idiomorphs, which is a candidate to be involved in the maintenance of the heterokaryotic state, since the S mat+ and S mat- strains have different physiology that may enable hybrid-vigor-like phenomena in the heterokaryons. The mat region contains 229 coding sequences. A total of 687 polymorphisms were detected between the S mat+ and S mat- chromosomes. Importantly, the mat region is colinear between both chromosomes, which calls for an original mechanism of recombination inhibition. Microarray analyses revealed that 10% of the P. anserina genes have different transcriptional profiles in S mat+ and S mat-, in line with their different phenotypes. Finally, we show that the heterokaryotic state is faithfully maintained during mycelium growth of P. anserina, yet mat+/mat+ and mat-/mat- heterokaryons are as stable as mat+/mat- ones, evidencing a maintenance of heterokaryosis that does not rely on fitness-enhancing complementation between the S mat+ and S mat- strains.

Collaboration between research scientists and educators to prepare new Earth Science teachers

NASA Astrophysics Data System (ADS)

Pagnotta, Ashley; Grcevich, J.; Shara, M.; Mac Low, M.; Flores, K.; Nadeau, P. A.; Sessa, J.; Ustunisik, G.; Zirakparvar, N.; Ebel, D.; Harlow, G.; Webster, J. D.; Kinzler, R.; MacDonald, M. B.; Contino, J.; Cooke-Nieves, N.; Howes, E.; Zachowski, M.

2014-01-01

The Master of Arts in Teaching (MAT) Program at the American Museum of Natural History is a first-of-its-kind program designed to prepare participants to be world-class Earth Science teachers. The lack of Earth Science teachers in New York State has resulted in fewer students taking the statewide Earth Science Regents Exam, which negatively affects graduation rates and reduces the number of students who pursue related college degrees. The MAT program was designed to address this problem, and is the result of a collaboration between research scientists and educators at the Museum, with faculty comprised of curators and postdoctoral researchers from the Departments of Astrophysics, Earth and Planetary Sciences, and the Division of Paleontology, as well as doctoral-level Education faculty. The full-time, 15-month program combines courses and field work in astrophysics, geology, earth science, and paleontology at the Museum with pedagogical coursework and a teaching residency in local urban classrooms. The MAT program targets high-needs schools with diverse student populations and therefore has the potential to stimulate interest and achievement in a variety of STEM fields among thousands of students from traditionally underrepresented backgrounds. The first cohort of candidates entered the MAT program in June of 2012 and finished in August of 2013. Nineteen new Regents-qualified Earth Science teachers are now in full-time teaching positions at high-needs schools in New York State. We report on the experience of the first cohort as well as the continuation of the program for current and future cohorts of teacher candidates.

Lacking Ketohexokinase-A Exacerbates Renal Injury in Streptozotocin-induced Diabetic Mice.

PubMed

Doke, Tomohito; Ishimoto, Takuji; Hayasaki, Takahiro; Ikeda, Satsuki; Hasebe, Masako; Hirayama, Akiyoshi; Soga, Tomoyoshi; Kato, Noritoshi; Kosugi, Tomoki; Tsuboi, Naotake; Lanaspa, Miguel A; Johnson, Richard J; Kadomatsu, Kenji; Maruyama, Shoichi

2018-03-28

Ketohexokinase (KHK), a primary enzyme in fructose metabolism, has two isoforms, namely, KHK-A and KHK-C. Previously, we reported that renal injury was reduced in streptozotocin-induced diabetic mice which lacked both isoforms. Although both isoforms express in kidney, it has not been elucidated whether each isoform plays distinct roles in the development of diabetic kidney disease (DKD). The aim of the study is to elucidate the role of KHK-A for DKD progression. Diabetes was induced by five consecutive daily intraperitoneal injections of streptozotocin (50 mg/kg) in C57BL/6 J wild-type mice, mice lacking KHK-A alone (KHK-A KO), and mice lacking both KHK-A and KHK-C (KHK-A/C KO). At 35 weeks, renal injury, inflammation, hypoxia, and oxidative stress were examined. Metabolomic analysis including polyol pathway, fructose metabolism, glycolysis, TCA (tricarboxylic acid) cycle, and NAD (nicotinamide adenine dinucleotide) metabolism in kidney and urine was done. Diabetic KHK-A KO mice developed severe renal injury compared to diabetic wild-type mice, and this was associated with further increases of intrarenal fructose, dihydroxyacetone phosphate (DHAP), TCA cycle intermediates levels, and severe inflammation. In contrast, renal injury was prevented in diabetic KHK-A/C KO mice compared to both wild-type and KHK-A KO diabetic mice. Further, diabetic KHK-A KO mice contained decreased renal NAD + level with the increase of renal hypoxia-inducible factor 1-alpha expression despite having increased renal nicotinamide (NAM) level. These results suggest that KHK-C might play a deleterious role in DKD progression through endogenous fructose metabolism, and that KHK-A plays a unique protective role against the development of DKD. Copyright © 2018. Published by Elsevier Inc.

Grating acuity at different luminances in wild-type mice and in mice lacking rod or cone function.

PubMed

Schmucker, Christine; Seeliger, Mathias; Humphries, Pete; Biel, Martin; Schaeffel, Frank

2005-01-01

The mouse eye has become an important model in vision research. However, it is not known how visual acuity changes with luminance. Therefore, grating acuity of mice was measured at different luminances in an automated optomotor paradigm. Furthermore, mutant mice lacking either rods (RHO-/- and CNGB1-/-) or cones (CNGA3-/-), or both, were studied to determine the rod and cone contribution to visual acuity. Freely ranging individual mice were automatically tracked at a 25-Hz sampling rate with a self-programmed video system in a large rotating optomotor drum. The drum had a square-wave grating inside with adjustable spatial frequency. The angular speed of the mice with respect to the center of the drum and the angular orientation of the snout-tail body axis were analyzed. In addition, the motor activity of the wild-type mice was recorded at different luminances. The optomotor drum provided reliable data on visual input to the mouse's behavior and was convenient to use, since the experimenter's had only to place the mice individually in a Perspex cylinder. Optomotor grating acuity of the wild-type mice was limited to 0.3 to 0.4 cyc/deg. Maximum optomotor responses were obtained at 0.1 to 0.2 cyc/deg. The importance of visual input declined monotonically with decreasing luminance (30 cd/m2, 100%; 0.1 cd/m2, 76.4%; 0.005 cd/m2, 45.9%; and darkness, -9%). Mice lacking functional rods were able to resolve gratings up to 0.1 cyc/deg at 30 cd/m2. Surprisingly, mice lacking functional cones had an optomotor acuity that was similar to the wild-type. Double-knockout mice without rods and cones had no detectable grating acuity. Because the visual system of the mouse is more responsive at bright luminances, experiments in which visual input is important should be performed in photopic conditions (30 cd/m2 or even more). Apparently, spatial vision is governed by the rod system, which is not saturated in the mesopic or low photopic range. Mice lacking both rods and cones have no detectable grating acuity, indicating that the retinal melanopsin system does not contribute to spatial vision.

Automatic content-based analysis of georeferenced image data: Detection of Beggiatoa mats in seafloor video mosaics from the HÅkon Mosby Mud Volcano

NASA Astrophysics Data System (ADS)

Jerosch, K.; Lüdtke, A.; Schlüter, M.; Ioannidis, G. T.

2007-02-01

The combination of new underwater technology as remotely operating vehicles (ROVs), high-resolution video imagery, and software to compute georeferenced mosaics of the seafloor provides new opportunities for marine geological or biological studies and applications in offshore industry. Even during single surveys by ROVs or towed systems large amounts of images are compiled. While these underwater techniques are now well-engineered, there is still a lack of methods for the automatic analysis of the acquired image data. During ROV dives more than 4200 georeferenced video mosaics were compiled for the HÅkon Mosby Mud Volcano (HMMV). Mud volcanoes as HMMV are considered as significant source locations for methane characterised by unique chemoautotrophic communities as Beggiatoa mats. For the detection and quantification of the spatial distribution of Beggiatoa mats an automated image analysis technique was developed, which applies watershed transformation and relaxation-based labelling of pre-segmented regions. Comparison of the data derived by visual inspection of 2840 video images with the automated image analysis revealed similarities with a precision better than 90%. We consider this as a step towards a time-efficient and accurate analysis of seafloor images for computation of geochemical budgets and identification of habitats at the seafloor.

Studies of the Tumor Microenvironment in Pathogenesis of Neuroblastoma

DTIC Science & Technology

2012-07-01

DISTRIBUTION / AVAILABILITY STATEMENT 13. SUPPLEMENTARY NOTES 14. ABSTRACT The NBL -Tag neuroblastoma mice were crossed with B-cell... NBL -Tag mice were established. The NBL -Tag/B-cell deficient mice lacked B-cells as expected using flow cytometry analyses and immunohistochemistry...However, the lack of B-cells did not alter the growth patterns of NBL -Tag tumor formation as imaged by MRI. Studies using anti-B cell therapy were

Regulation of electron transfer processes affects phototrophic mat structure and activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ha, Phuc T.; Renslow, Ryan S.; Atci, Erhan

Phototrophic microbial mats are among the most diverse ecosystems in nature. These systems undergo daily cycles in redox potential caused by variations in light energy input and metabolic interactions among the microbial species. In this work, solid electrodes with controlled potentials were placed under mats to study the electron transfer processes between the electrode and the microbial mat. The phototrophic microbial mat was harvested from Hot Lake, a hypersaline, epsomitic lake located near Oroville (Washington, USA). We operated two reactors: graphite electrodes were polarized at potentials of -700 mV Ag/AgCl [cathodic (CAT) mat system] and +300 mV Ag/AgCl [anodic (AN)more » mat system] and the electron transfer rates between the electrode and mat were monitored. We observed a diel cycle of electron transfer rates for both AN and CAT mat systems. Interestingly, the CAT mats generated the highest reducing current at the same time points that the AN mats showed the highest oxidizing current. To characterize the physicochemical factors influencing electron transfer processes, we measured depth profiles of dissolved oxygen (DO) and sulfide in the mats using microelectrodes. We further demonstrated that the mat-to-electrode and electrode-to-mat electron transfer rates were light- and temperature-dependent. Using nuclear magnetic resonance (NMR) imaging, we determined that the electrode potential regulated the diffusivity and porosity of the microbial mats. Both porosity and diffusivity were higher in the CAT mats than in the AN mats. We also used NMR spectroscopy for high-resolution quantitative metabolite analysis and found that the CAT mats had significantly higher concentrations of osmoprotectants such as betaine and trehalose. Subsequently, we performed amplicon sequencing across the V4 region of the 16S rRNA gene of incubated mats to understand the impact of electrode potential on microbial community structure. In conclusion, these data suggested that variation in the electrochemical conditions under which mats were generated significantly impacted the relative abundances of mat members and mat metabolism.« less

Regulation of electron transfer processes affects phototrophic mat structure and activity

DOE PAGES

Ha, Phuc T.; Renslow, Ryan S.; Atci, Erhan; ...

2015-09-03

Phototrophic microbial mats are among the most diverse ecosystems in nature. These systems undergo daily cycles in redox potential caused by variations in light energy input and metabolic interactions among the microbial species. In this work, solid electrodes with controlled potentials were placed under mats to study the electron transfer processes between the electrode and the microbial mat. The phototrophic microbial mat was harvested from Hot Lake, a hypersaline, epsomitic lake located near Oroville (Washington, USA). We operated two reactors: graphite electrodes were polarized at potentials of -700 mV Ag/AgCl [cathodic (CAT) mat system] and +300 mV Ag/AgCl [anodic (AN)more » mat system] and the electron transfer rates between the electrode and mat were monitored. We observed a diel cycle of electron transfer rates for both AN and CAT mat systems. Interestingly, the CAT mats generated the highest reducing current at the same time points that the AN mats showed the highest oxidizing current. To characterize the physicochemical factors influencing electron transfer processes, we measured depth profiles of dissolved oxygen (DO) and sulfide in the mats using microelectrodes. We further demonstrated that the mat-to-electrode and electrode-to-mat electron transfer rates were light- and temperature-dependent. Using nuclear magnetic resonance (NMR) imaging, we determined that the electrode potential regulated the diffusivity and porosity of the microbial mats. Both porosity and diffusivity were higher in the CAT mats than in the AN mats. We also used NMR spectroscopy for high-resolution quantitative metabolite analysis and found that the CAT mats had significantly higher concentrations of osmoprotectants such as betaine and trehalose. Subsequently, we performed amplicon sequencing across the V4 region of the 16S rRNA gene of incubated mats to understand the impact of electrode potential on microbial community structure. In conclusion, these data suggested that variation in the electrochemical conditions under which mats were generated significantly impacted the relative abundances of mat members and mat metabolism.« less

Elevated FGF23 Levels in Mice Lacking the Thiazide-Sensitive NaCl cotransporter (NCC).

PubMed

Pathare, Ganesh; Anderegg, Manuel; Albano, Giuseppe; Lang, Florian; Fuster, Daniel G

2018-02-26

Fibroblast growth factor 23 (FGF23) participates in the orchestration of mineral metabolism by inducing phosphaturia and decreasing the production of 1,25(OH) 2 D 3 . It is known that FGF23 release is stimulated by aldosterone and extracellular volume depletion. To characterize this effect further in a model of mild hypovolemia, we studied mice lacking the thiazide sensitive NaCl cotransporter (NCC). Our data indicate that NCC knockout mice (KO) have significantly higher FGF23, PTH and aldosterone concentrations than corresponding wild type (WT) mice. However, 1,25(OH) 2 D 3 , fractional phosphate excretion and renal brush border expression of the sodium/phosphate co-transporter 2a were not different between the two genotypes. In addition, renal expression of FGF23 receptor FGFR1 and the co-receptor Klotho were unaltered in NCC KO mice. FGF23 transcript was increased in the bone of NCC KO mice compared to WT mice, but treatment of primary murine osteoblasts with the NCC inhibitor hydrochlorothiazide did not elicit an increase of FGF23 transcription. In contrast, the mineralocorticoid receptor blocker eplerenone reversed excess FGF23 levels in KO mice but not in WT mice, indicating that FGF23 upregulation in NCC KO mice is primarily aldosterone-mediated. Together, our data reveal that lack of renal NCC causes an aldosterone-mediated upregulation of circulating FGF23.

Prevalence and genetic characterization of Toxoplasma gondii in free-range chickens from grocery stores and farms in Maryland, Ohio and Massachusetts, USA.

PubMed

Ying, Yuqing; Verma, Shiv K; Kwok, Oliver C H; Alibana, Fatima; Mcleod, Rima; Su, Chunlei; Dubey, Jitender P; Pradhan, Abani K

2017-05-01

Chickens are considered important in the epidemiology of Toxoplasma gondii. Chicken hearts (n = 1185) obtained from grocery stores were tested for T. gondii infection. Antibodies to T. gondii were assayed in fluid removed from the heart cavity using the modified agglutination test (MAT) at 1:5, 1:25, and 1:100 dilutions. MAT antibodies were detected in 222 hearts at 1:5 dilution and 8 hearts at 1:25 dilution, but none were positive at 1:100 dilution. Seropositive (n = 230, 19.4%) chicken hearts were bioassayed in mice and seronegative (n = 157) chickens were bioassayed in cats. Viable T. gondii was not isolated from any hearts by bioassays in mice. The 2 cats fed 60 and 97 hearts did not excrete T. gondii oocysts. The results indicate a low prevalence of viable T. gondii in chickens from grocery stores. Molecular typing of 23 archived T. gondii strains isolated from free-range chickens from Ohio and Massachusetts using the 10 PCR-RFLP markers including SAG1, SAG2 (5'-3'SAG2 and altSAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico revealed that seven were ToxoDB PCR-RFLP genotype #1, 11 were genotype #2, one was genotype #3, three were genotype #170, and one was mixed genotype. These results indicate that the clonal genotypes #1 (type II), #2 (type III), and #3 (type II variant) are common in free-range chickens.

High prevalence and genotypes of Toxoplasma gondii isolated from organic pigs in northern USA.

PubMed

Dubey, J P; Hill, D E; Rozeboom, D W; Rajendran, C; Choudhary, S; Ferreira, L R; Kwok, O C H; Su, C

2012-08-13

The ingestion of undercooked pork infected with Toxoplasma gondii is considered an important source of transmission of this parasite. While T. gondii infection in confinement raised market pigs (market pigs are typically used for fresh, unprocessed pork products) in the USA has decreased significantly over the last 20 years, infection levels in pigs with access to the outdoors can be quite high. An upsurge in consumer demand for 'organically raised', 'humanely raised' and 'free range' pork products has resulted in increasing numbers of hogs being raised in non-confinement systems. To determine T. gondii infection rate in these organic pigs, prevalence of T. gondii in organically raised pigs in two establishments (Farm 1, Farm 2) in Michigan was investigated. Serum and tissue samples from 33 pigs on the farm were available for T. gondii evaluation at slaughter. Serological testing was performed using both ELISA and the modified agglutination test (MAT). Antibodies to T. gondii were detected by both ELISA and MAT in 30 of 33 animals with MAT titers of 1:25 in three, 1:50 in six, 1:100 in seven, 1:200 in 13, and 1:400 in one. Hearts of all 33 pigs were bioassayed for T. gondii in mice; T. gondii was isolated from 17 pigs including one from a seronegative (both ELISA and MAT) pig. Genetic typing of 16 of the 17 T. gondii isolates using the SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico loci revealed clonal Type II from Farm 1 and clonal Type III on Farm 2. These results revealed very high prevalence of T. gondii in organic pigs for the first time in USA, indicating potentially increased health risk of consuming organic swine products. Published by Elsevier B.V.

Promoting Health and Safety in San Francisco's Chinatown Restaurants: Findings and Lessons Learned from a Pilot Observational Checklist

PubMed Central

Gaydos, Megan; Bhatia, Rajiv; Morales, Alvaro; Lee, Pam Tau; Liu, Shaw San; Chang, Charlotte; Salvatore, Alicia L.; Krause, Niklas; Minkler, Meredith

2011-01-01

Noncompliance with labor and occupational health and safety laws contributes to economic and health inequities. Environmental health agencies are well positioned to monitor workplace conditions in many industries and support enhanced enforcement by responsible regulatory agencies. In collaboration with university and community partners, the San Francisco Department of Public Health used an observational checklist to assess preventable occupational injury hazards and compliance with employee notification requirements in 106 restaurants in San Francisco's Chinatown. Sixty-five percent of restaurants had not posted required minimum wage, paid sick leave, or workers' compensation notifications; 82% of restaurants lacked fully stocked first-aid kits; 52% lacked antislip mats; 37% lacked adequate ventilation; and 28% lacked adequate lighting. Supported by a larger community-based participatory research process, this pilot project helped to spur additional innovative health department collaborations to promote healthier workplaces. PMID:21836739

The Architecture of Iron Microbial Mats Reflects the Adaptation of Chemolithotrophic Iron Oxidation in Freshwater and Marine Environments

PubMed Central

Chan, Clara S.; McAllister, Sean M.; Leavitt, Anna H.; Glazer, Brian T.; Krepski, Sean T.; Emerson, David

2016-01-01

Microbes form mats with architectures that promote efficient metabolism within a particular physicochemical environment, thus studying mat structure helps us understand ecophysiology. Despite much research on chemolithotrophic Fe-oxidizing bacteria, Fe mat architecture has not been visualized because these delicate structures are easily disrupted. There are striking similarities between the biominerals that comprise freshwater and marine Fe mats, made by Beta- and Zetaproteobacteria, respectively. If these biominerals are assembled into mat structures with similar functional morphology, this would suggest that mat architecture is adapted to serve roles specific to Fe oxidation. To evaluate this, we combined light, confocal, and scanning electron microscopy of intact Fe microbial mats with experiments on sheath formation in culture, in order to understand mat developmental history and subsequently evaluate the connection between Fe oxidation and mat morphology. We sampled a freshwater sheath mat from Maine and marine stalk and sheath mats from Loihi Seamount hydrothermal vents, Hawaii. Mat morphology correlated to niche: stalks formed in steeper O2 gradients while sheaths were associated with low to undetectable O2 gradients. Fe-biomineralized filaments, twisted stalks or hollow sheaths, formed the highly porous framework of each mat. The mat-formers are keystone species, with nascent marine stalk-rich mats comprised of novel and uncommon Zetaproteobacteria. For all mats, filaments were locally highly parallel with similar morphologies, indicating that cells were synchronously tracking a chemical or physical cue. In the freshwater mat, cells inhabited sheath ends at the growing edge of the mat. Correspondingly, time lapse culture imaging showed that sheaths are made like stalks, with cells rapidly leaving behind an Fe oxide filament. The distinctive architecture common to all observed Fe mats appears to serve specific functions related to chemolithotrophic Fe oxidation, including (1) removing Fe oxyhydroxide waste without entombing cells or clogging flow paths through the mat and (2) colonizing niches where Fe(II) and O2 overlap. This work improves our understanding of Fe mat developmental history and how mat morphology links to metabolism. We can use these results to interpret biogenicity, metabolism, and paleoenvironmental conditions of Fe microfossil mats, which would give us insight into Earth's Fe and O2 history. PMID:27313567

Primary hepatocytes from mice lacking cysteine dioxygenase show increased cysteine concentrations and higher rates of metabolism of cysteine to hydrogen sulfide and thiosulfate

PubMed Central

Jurkowska, Halina; Roman, Heather B.; Hirschberger, Lawrence L.; Sasakura, Kiyoshi; Nagano, Tetsuo; Hanaoka, Kenjiro; Krijt, Jakub

2016-01-01

The oxidation of cysteine in mammalian cells occurs by two routes: a highly regulated direct oxidation pathway in which the first step is catalyzed by cysteine dioxygenase (CDO) and by desulfhydration-oxidation pathways in which the sulfur is released in a reduced oxidation state. To assess the effect of a lack of CDO on production of hydrogen sulfide (H2S) and thiosulfate (an intermediate in the oxidation of H2S to sulfate) and to explore the roles of both cystathionine γ-lyase (CTH) and cystathionine β-synthase (CBS) in cysteine desulfhydration by liver, we investigated the metabolism of cysteine in hepatocytes isolated from Cdo1-null and wild-type mice. Hepatocytes from Cdo1-null mice produced more H2S and thiosulfate than did hepatocytes from wild-type mice. The greater flux of cysteine through the cysteine desulfhydration reactions catalyzed by CTH and CBS in hepatocytes from Cdo1-null mice appeared to be the consequence of their higher cysteine levels, which were due to the lack of CDO and hence lack of catabolism of cysteine by the cysteinesulfinate-dependent pathways. Both CBS and CTH appeared to contribute substantially to cysteine desulfhydration, with estimates of 56 % by CBS and 44 % by CTH in hepatocytes from wild-type mice, and 63 % by CBS and 37 % by CTH in hepatocytes from Cdo1-null mice. PMID:24609271

Targeting S-adenosylmethionine biosynthesis with a novel allosteric inhibitor of Mat2A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quinlan, Casey L.; Kaiser, Stephen E.; Bolaños, Ben

S-Adenosyl-L-methionine (SAM) is an enzyme cofactor used in methyl transfer reactions and polyamine biosynthesis. The biosynthesis of SAM from ATP and L-methionine is performed by the methionine adenosyltransferase enzyme family (Mat; EC 2.5.1.6). Human methionine adenosyltransferase 2A (Mat2A), the extrahepatic isoform, is often deregulated in cancer. We identified a Mat2A inhibitor, PF-9366, that binds an allosteric site on Mat2A that overlaps with the binding site for the Mat2A regulator, Mat2B. Studies exploiting PF-9366 suggested a general mode of Mat2A allosteric regulation. Allosteric binding of PF-9366 or Mat2B altered the Mat2A active site, resulting in increased substrate affinity and decreased enzymemore » turnover. These data support a model whereby Mat2B functions as an inhibitor of Mat2A activity when methionine or SAM levels are high, yet functions as an activator of Mat2A when methionine or SAM levels are low. The ramification of Mat2A activity modulation in cancer cells is also described.« less

Geochemistry and microbiology at gas hydrate and mud volcano sites in the black sea

NASA Astrophysics Data System (ADS)

Drews, M.; Schmaljohann, R.; Wallmann, K.

2003-04-01

We present geochemical and microbiological results which were obtained from sediments at gas hydrate and mud volcano sites in the Sorokin Trough (northern Black Sea, south east of the Crimean peninsula) at water depths of about 1800 to 2100 m during the METEOR cruise 52-1. The surface near sub-bottom accumulations of gas hydrates (occuring at depths of several meters or less beneath the sea floor) in the Black Sea are associated with numerous mud volcanos. At stations we investigated gas hydrates occurred below 10 cm to 100 cm with a significant influence on the sediment biochemistry. Analyses revealed high methane concentrations, anoxic and sulfidic conditions, a steep sulfate gradient, carbonate precipitation, and high anaerobic methane oxidation rates. In proximity of the so called Odessa mud volcano one investigated sampling station showed maximum methane oxidation rates in the depth horizon of a firm 2 cm thick carbonate crust layer, adhered to by a bacterial mat. This observation is taken to indicate that the bacteria are causing or mediating the crust formation by their anaerobic methane oxidation metabolism. The station was further characterised by two layers of gas hydrate fragments and lenses below 1 m depth. A 2 to 4 cm thick carbonate crust with attached bacterial mat from a Yalta mud vulcano sample (2124 m water depth) was investigated under the scanning electron microscope. The stiff gelatinous mat showed a dense and morphologically uniform population of rod shaped bacteria with only a few nests of coccoid cells. Purified mat material exhibited anaerobic methane oxidation activity. These mats resemble the type previously found in the shallow NW methane seep area of the Black Sea, where it covers carbonate chimneys. Samples from two sites atop the summit of the active but flat-topped Dvurechenskii mud volcano were characterised by very high methane oxidation rates (up to 563 nmol/cm3/d) at the sediment surface. Strong pore water gradients of chloride, bromide, ammonium, methane, and temperature proved the existence of a rich upward flow of warm fluids from the deeper sediment. At both stations no carbonate crusts or bacterial mats were found. The lack of hemipelagic sediments and at the same time abundance of mud breccia gives ample evidence of the recency of the mud flow.

Reduced alcohol consumption in mice lacking preprodynorphin.

PubMed Central

Blednov, Yuri A.; Walker, Danielle; Martinez, Marni; Harris., R. Adron

2007-01-01

Many studies suggest a role for endogenous opioid peptides and their receptors in regulation of ethanol intake. It is commonly accepted that the κ-opioid receptors and their endogenous ligands, dynorphins, produce a dysphoric state and therefore may be responsible for avoidance of alcohol. We used mutant mice lacking preprodynorphin in a variety of behavioral tests of alcohol actions. Null mutant female, but not male, mice showed significantly lower preference for alcohol and consumed lower amounts of alcohol in a two-bottle choice test as compared with wild-type littermates. In the same test, knockout mice of both sexes showed a strong reduction of preference for saccharin compared to control mice. In contrast, under conditions of limited (4 hours) access (light phase of the light/dark cycle), null mutant mice did not show any differences in consumption of saccharin but they showed significantly reduced intake of sucrose. To determine the possible cause for reduction of ethanol preference and intake, we studied other ethanol-related behaviors in mice lacking the preprodynorphin gene. There were no differences between null mutant and wild type mice in ethanol-induced loss of righting reflex, acute ethanol withdrawal, ethanol-induced conditioned place preference or conditioned taste aversion to ethanol. These results indicate that deletion of preprodynorphin leads to substantial reduction of alcohol intake in female mice, and suggest thath this is caused by decreased orosensory reward of alcohol (sweet taste and/or palatability). PMID:17307643

Reduced alcohol consumption in mice lacking preprodynorphin.

PubMed

Blednov, Yuri A; Walker, Danielle; Martinez, Marni; Harris, R Adron

2006-10-01

Many studies suggest a role for endogenous opioid peptides and their receptors in regulation of ethanol intake. It is commonly accepted that the kappa-opioid receptors and their endogenous ligands, dynorphins, produce a dysphoric state and therefore may be responsible for avoidance of alcohol. We used mutant mice lacking preprodynorphin in a variety of behavioral tests of alcohol actions. Null mutant female, but not male, mice showed significantly lower preference for alcohol and consumed lower amounts of alcohol in a two-bottle choice test as compared with wild-type littermates. In the same test, knockout mice of both sexes showed a strong reduction of preference for saccharin compared to control mice. In contrast, under conditions of limited (4 h) access (light phase of the light/dark cycle), null mutant mice did not show any differences in consumption of saccharin, but they showed significantly reduced intake of sucrose. To determine the possible cause for reduction of ethanol preference and intake, we studied other ethanol-related behaviors in mice lacking the preprodynorphin gene. There were no differences between null mutant and wild-type mice in ethanol-induced loss of righting reflex, acute ethanol withdrawal, ethanol-induced conditioned place preference, or conditioned taste aversion to ethanol. These results indicate that deletion of preprodynorphin leads to substantial reduction of alcohol intake in female mice, and suggest that this is caused by decreased orosensory reward of alcohol (sweet taste and/or palatability).

Male and Female Mice Lacking Neuroligin-3 Modify the Behavior of Their Wild-Type Littermates.

PubMed

Kalbassi, Shireene; Bachmann, Sven O; Cross, Ellen; Roberton, Victoria H; Baudouin, Stéphane J

2017-01-01

In most mammals, including humans, the postnatal acquisition of normal social and nonsocial behavior critically depends on interactions with peers. Here we explore the possibility that mixed-group housing of mice carrying a deletion of Nlgn3 , a gene associated with autism spectrum disorders, and their wild-type littermates induces changes in each other's behavior. We have found that, when raised together, male Nlgn3 knockout mice and their wild-type littermates displayed deficits in sociability. Moreover, social submission in adult male Nlgn3 knockout mice correlated with an increase in their anxiety. Re-expression of Nlgn3 in parvalbumin-expressing cells in transgenic animals rescued their social behavior and alleviated the phenotype of their wild-type littermates, further indicating that the social behavior of Nlgn3 knockout mice has a direct and measurable impact on wild-type animals' behavior. Finally, we showed that, unlike male mice, female mice lacking Nlgn3 were insensitive to their peers' behavior but modified the social behavior of their littermates. Altogether, our findings show that the environment is a critical factor in the development of behavioral phenotypes in transgenic and wild-type mice. In addition, these results reveal that the social environment has a sexually dimorphic effect on the behavior of mice lacking Nlgn3 , being more influential in males than females.

Male and Female Mice Lacking Neuroligin-3 Modify the Behavior of Their Wild-Type Littermates

PubMed Central

Kalbassi, Shireene; Cross, Ellen

2017-01-01

Abstract In most mammals, including humans, the postnatal acquisition of normal social and nonsocial behavior critically depends on interactions with peers. Here we explore the possibility that mixed-group housing of mice carrying a deletion of Nlgn3, a gene associated with autism spectrum disorders, and their wild-type littermates induces changes in each other’s behavior. We have found that, when raised together, male Nlgn3 knockout mice and their wild-type littermates displayed deficits in sociability. Moreover, social submission in adult male Nlgn3 knockout mice correlated with an increase in their anxiety. Re-expression of Nlgn3 in parvalbumin-expressing cells in transgenic animals rescued their social behavior and alleviated the phenotype of their wild-type littermates, further indicating that the social behavior of Nlgn3 knockout mice has a direct and measurable impact on wild-type animals’ behavior. Finally, we showed that, unlike male mice, female mice lacking Nlgn3 were insensitive to their peers’ behavior but modified the social behavior of their littermates. Altogether, our findings show that the environment is a critical factor in the development of behavioral phenotypes in transgenic and wild-type mice. In addition, these results reveal that the social environment has a sexually dimorphic effect on the behavior of mice lacking Nlgn3, being more influential in males than females. PMID:28795135

Polyamine and methionine adenosyltransferase 2A crosstalk in human colon and liver cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tomasi, Maria Lauda; USC Research Center for Liver Diseases, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033; The Southern California Research Center for Alcoholic and Pancreatic Diseases and Cirrhosis, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033

Methionine adenosyltransferase (MAT) is an essential enzyme that is responsible for the biosynthesis of S-adenosylmethionine (SAMe), the principal methyl donor and precursor of polyamines. MAT1A is expressed in normal liver and MAT2A is expressed in all extrahepatic tissues. MAT2A expression is increased in human colon cancer and in colon cancer cells treated with mitogens, whereas silencing MAT2A resulted in apoptosis. The aim of the current work was to examine the mechanism responsible for MAT2A-dependent growth and apoptosis. We found that in RKO (human adenocarcinoma cell line) cells, MAT2A siRNA treatment lowered cellular SAMe and putrescine levels by 70–75%, increased apoptosismore » and inhibited growth. Putrescine supplementation blunted significantly MAT2A siRNA-induced apoptosis and growth suppression. Putrescine treatment (100 pmol/L) raised MAT2A mRNA level to 4.3-fold of control, increased the expression of c-Jun and c-Fos and binding to an AP-1 site in the human MAT2A promoter and the promoter activity. In human colon cancer specimens, the expression levels of MAT2A, ornithine decarboxylase (ODC), c-Jun and c-Fos are all elevated as compared to adjacent non-tumorous tissues. Overexpression of ODC in RKO cells also raised MAT2A mRNA level and MAT2A promoter activity. ODC and MAT2A are also overexpressed in liver cancer and consistently, similar MAT2A-ODC-putrescine interactions and effects on growth and apoptosis were observed in HepG2 cells. In conclusion, there is a crosstalk between polyamines and MAT2A. Increased MAT2A expression provides more SAMe for polyamines biosynthesis; increased polyamine (putrescine in this case) can activate MAT2A at the transcriptional level. This along with increased ODC expression in cancer all feed forward to further enhance the proliferative capacity of the cancer cell. -- Highlights: • MAT2A knockdown depletes putrescine and leads to apoptosis. • Putrescine attenuates MAT2A knockdown-induced apoptosis and growth suppression. • Putrescine induces AP-1, which activates MAT2A promoter to increase its expression. • Putrescine increases ornithine decarboxylase expression, which induce MAT2A promoter. • Expression of MAT2A correlates with that of ornithine decarboxylase in colon cancer.« less

Assessing the biological contribution to microbialite growth and morphogenesis utilizing lipid biomarkers

NASA Astrophysics Data System (ADS)

Beeler, S. R.; Gomez, F. J.; Bradley, A. S.

2016-12-01

Microbialites are sedimentary structures that arise from the interaction of microbial, geochemical, and physical processes. These structures are among the oldest evidence for life on Earth, and are abundant through much of the Proterozoic before declining in the Phanerozoic. Microbialites are of great importance geobiologically as they provide a record of microbial life and its interaction with the environment throughout Earth history. Yet, our capacity to use microbialites to reconstruct biological processes on ancient Earth is complicated by our lack of understanding of the mechanisms controlling the formation of these structures. The modern microbialites of Laguna Negra in northeastern Argentina [1] offer an opportunity to examine the biological and geochemical differences among microbialites displaying distinct morphological diversity in a single setting. Three broad types of microbialites are found at this site: oncoids, stromatolites, and laminar crusts. Each of these types of microbialites are associated with visually distinct microbial mats. We have examined the structural and isotopic composition of lipid biomarkers from each of these microbialite types, and their associated mats. Sterol profiles detected from microbial mats and microbialites showed abundant C27 to C29 sterols and indicate that primary producers are dominated by algae. Decreased abundances of more labile unsaturated fatty acids relative to more recalcitrant saturated fatty acids were observed in microbialites compared to extant mats suggesting preferential loss of these compounds during diagenesis. Among the three different microbialite morphologies, no statistically discernable differences in biomarker profiles were detected. This implies that morphological changes are due to either geochemical/physical changes across the zone of microbialite formation or changes in community structure that are not observable in the present biomarker set. [1] Gomez et al. (2014) Palaios 29, 233-249

Mosaicism for maternal uniparental disomy 15 in a boy with some clinical features of Prader-Willi syndrome.

PubMed

Zilina, Olga; Kahre, Tiina; Talvik, Inga; Oiglane-Shlik, Eve; Tillmann, Vallo; Ounap, Katrin

2014-01-01

Prader-Willi syndrome (PWS) is caused by the lack of paternal expression of imprinted genes in the human chromosomal region 15q11.2-q13.2, which can be due to an interstitial deletion at 15q11.2-q13 of paternal origin (65-75%), maternal uniparental disomy (matUPD) of chromosome 15 (20-30%), or an imprinting defect (1-3%). The majority of PWS-associated matUPD15 cases represent a complete heterodisomy of chromosome 15 or a mixture of hetero- and isodisomic regions across the chromosome 15. Pure maternal isodisomy is observed in only a few matUPD15 patients. Here we report a case of an 18-year-old boy with some clinical features of Prader-Willi syndrome, such as overweight, muscular hypotonia, facial dysmorphism and psychiatric problems, but there was no reason to suspect PWS in the patient based solely on the phenotype estimation. However, chromosomal microarray analysis (CMA) revealed mosaic loss of heterozygosity of the entire chromosome 15. Methylation-specific multiplex ligation-dependant probe amplification (MS-MLPA) analysis showed hypermethylation of the SNRPN and NDN genes in the PWS/AS critical region of chromosome 15 in this patient. Taking into consideration the MS-MLPA results and the presence of PWS features in the patient, we concluded that it was matUPD15, although the patient's parents were not enrolled in the study. According to CMA and karyotyping, no trisomic or monosomic cells were present. To the best of our knowledge, only two PWS cases with mosaic maternal isodisomy 15 and without trisomic/monosomic cell lines have been reported so far. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Characterization of [3H] oxymorphone binding sites in mouse brain: Quantitative autoradiography in opioid receptor knockout mice.

PubMed

Yoo, Ji Hoon; Borsodi, Anna; Tóth, Géza; Benyhe, Sándor; Gaspar, Robert; Matifas, Audrey; Kieffer, Brigitte L; Metaxas, Athanasios; Kitchen, Ian; Bailey, Alexis

2017-03-16

Oxymorphone, one of oxycodone's metabolic products, is a potent opioid receptor agonist which is thought to contribute to the analgesic effect of its parent compound and may have high potential abuse liability. Nonetheless, the in vivo pharmacological binding profile of this drug is still unclear. This study uses mice lacking mu (MOP), kappa (KOP) or delta (DOP) opioid receptors as well as mice lacking all three opioid receptors to provide full characterisation of oxymorphone binding sites in the brain. Saturation binding studies using [ 3 H]oxymorphone revealed high affinity binding sites in mouse brain displaying Kd of 1.7nM and Bmax of 147fmol/mg. Furthermore, we performed quantitative autoradiography binding studies using [ 3 H]oxymorphone in mouse brain. The distribution of [ 3 H]oxymorphone binding sites was found to be similar to the selective MOP agonist [ 3 H]DAMGO in the mouse brain. [ 3 H]Oxymorphone binding was completely abolished across the majority of the brain regions in mice lacking MOP as well as in mice lacking all three opioid receptors. DOP and KOP knockout mice retained [ 3 H]oxymorphone binding sites suggesting oxymorphone may not target DOP or KOP. These results confirm that the MOP, and not the DOP or the KOP is the main high affinity binding target for oxymorphone. Copyright © 2017 Elsevier B.V. All rights reserved.

Oestrogen receptor specificity in oestradiol-mediated effects on B lymphopoiesis and immunoglobulin production in male mice

PubMed Central

Erlandsson, M C; Jonsson, C A; Islander, U; Ohlsson, C; Carlsten, H

2003-01-01

Oestrogen treatment down-regulates B lymphopoiesis in the bone marrow of mice. Meanwhile it up-regulates immunoglobulin production. To understand better the oestrogen action on bone marrow male mice lacking oestrogen receptor α (ERα; ERKO mice), lacking ERβ (BERKO mice), lacking both receptors (DERKO mice) or wild-type (wt) littermates were castrated and treated for 2·5 weeks with 30 μg/kg 17β-oestradiol (E2) or vehicle oil as controls. The B lymphopoiesis in the bone marrow was examined by flow cytometry and mature B-cell function was studied using an ELISPOT assay enumerating the B cells in bone marrow and spleen that were actively producing immunoglobulins. In wt mice the frequency of B-lymphopoietic (B220+) cells in the bone marrow decreased from 15% to 5% upon E2 treatment. In ERKO and BERKO mice significant reduction was seen but not of the same magnitude. In DERKO mice no reduction of B lymphopoiesis was seen. In addition, our results show that E2 mediated reduction of different steps in B lymphopoiesis require only ERα or both receptors. In wt and BERKO mice E2 treatment resulted in significantly increased levels of B cells actively producing immunoglobulin, while in ERKO and DERKO mice no such change was seen. Similar results were found in both bone marrow and spleen. In conclusion our results clearly show that both ERα and ERβ are required for complete down-regulation of B lymphopoiesis while only ERα is needed to up-regulate immunoglobulin production in both bone marrow and spleen. PMID:12603601

Identification And Survival Of Bacteriohopanepolyol In A Hot Spring Microbial Mat

NASA Technical Reports Server (NTRS)

Janke, Linda L.; Chang, Sherwood (Technical Monitor)

1995-01-01

The polar lipids of a hot spring microbial mat located in Yellowstone National Park were examined for the presence of bacteriohopanepolvols (BHP). BHP are a group of molecules consisting of a hopanoid (peotacyclic triterpene) linked via a n-alkyl polyhydroxylated chain to a variety of polar end groups. BHP have been isolated in varying amounts from phylogenetically diverse eubacterial groups including cyanobacteria, methanotrophs and the Rhodospirillaceae. The hopanoids are excellent biomarkers and have been detected in sedimentary rocks as old as 1.7 bya. In order to interpret the ancient organic record, it is important to understand the abundance, source and fate of such biomarker compounds in microbial mats. A 40 sq cm mat section was taken from a 52 to 55 C site in the effluent channel of Octopus Spring and was sampled vertically over approximately 16 mm. The first 5-6 mm was sectioned into a top green layer (310 mg dry weight) and several subjacent, deep orange layers (240 and 250 mg, respectively). The lower 10 mm of the mat was sectioned into two gelatinous orange layers containing a siliceous gritty material (260 and 440 mg) which increased with depth, and a bottom layer composed almost exclusively of siliceous sinter (4.1 g). The progressive decrease in total organic carbon from 45% in the top green layer to only 4% in the bottom layer reflects the observed increase in siliceous deposition. GC-MS analysis of the phospholipid and glycolipid fatty acids yielded predominantly saturated normal chain acids, n-15 to n-18, and iso-branched acids, i-15 to i-17. Small amounts of unsaturated fatty acids (16:1, two positional isomers of 18:1, and two cyclopropyl acids, C(sub 17) and C(sub 19)) were present mainly in the top layer. Esterified fatty acid which is a good index for intact cellular membrane, i.e. viable organisms, was highest in the top two layers (203 and 231 micro g/mg total lipid, respectively) and gradually decreased to 66 micro g/mg total lipid in the bottom layer. Small amounts of BHP were present in all six layers, however in this case, BHP was lowest in the top green and subjacent deep-orange layers (118 and 172 micro g/mg total lipid, respectively) and increased with depth reaching almost 400 micro g/mg in the bottom two layers. This data suggest that BHP are survivina the initial phase of mat degradation and may be preferentially enriched in any organic record of such thermal environments. The relatively low level of BHP in the top layer also suggests that cyanobacteria may not be the major source of BHP in this mat. Since Chloroflexus a major component of the deep-orange layer has been reported to lack BHP, this material may prove a valuable biomarker for some other mat inhabitant. Further isotopic characterization of this BHP should help resolve this finding.

Fast releasing oral electrospun PVP/CD nanofiber mats of taste-masked meloxicam.

PubMed

Samprasit, Wipada; Akkaramongkolporn, Prasert; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Kaomongkolgit, Ruchadaporn; Opanasopit, Praneet

2015-06-20

Fast release and taste masking of meloxicam (MX)-loaded polyvinylpyrrolidone (PVP)/cyclodextrin (CD) nanofiber mats were developed using an electrospinning process. CDs were blended to improve the stability of the mats. The morphology and diameter of the mats were determined using scanning electron microscopy (SEM); physical and mechanical properties were also studied. The MX content, disintegration time, MX release and cytotoxicity of the mats were investigated. In vivo studies were also performed in healthy human volunteers. The results indicated that the mats were successfully prepared with fiber in the nanometer range. MX was well incorporated into the mats, with an amorphous form. The mats showed suitable tensile strength. CDs improved the physical stability by their cage-like supramolecular structure to protect from humidity and moisture, and create bead free nanofiber mats. The nanofiber mats with CDs were physically stable without any hygroscopicity and fusion. A fast disintegration and release of MX was achieved. Moreover, this mat released MX faster than the MX powder and commercial tablets. The cytotoxicity test revealed that mats were safe for a 5-min incubation. The disintegration studies indicated that in vivo disintegration agreed with the in vitro studies; the mat rapidly disintegrated in the mouth. The less bitter of MX was occurred in the mats that incorporated CD, menthol and aspartame. In addition, this mat was physical stable for 6 months. The results suggest that these mats may be a good candidate for fast dissolving drug delivery systems of bitter drugs to increase the palatability of dosage forms. Copyright © 2015 Elsevier B.V. All rights reserved.

Vasodilator therapy with hydralazine induces angiotensin AT2 receptor-mediated cardiomyocyte growth in mice lacking guanylyl cyclase-A

PubMed Central

Li, Y; Saito, Y; Kuwahara, K; Rong, X; Kishimoto, I; Harada, M; Horiuchi, M; Murray, M; Nakao, K

2010-01-01

Background and purpose: Recent clinical guidelines advocate the use of the isosorbide dinitrate/hydralazine combination in treatment for heart failure. However, clinical and laboratory evidence suggest that some vasodilators may induce cardiac hypertrophy under uncertain conditions. This study investigated the effects and underlying mechanism of action of the vasodilator hydralazine on cardiac growth. Experimental approach: Wild-type mice and animals deficient in guanylyl cyclase-A (GCA) and/or angiotensin receptors (AT1 and AT2 subtypes) were treated with hydralazine (≈24 mg·kg−1·day−1 in drinking water) for 5 weeks. Cardiac mass and/or cardiomyocyte cross-sectional area, fibrosis (van Giessen-staining) and cardiac gene expression (real-time RT-PCR) were measured. Key results: Hydralazine lowered blood pressure in mice of all genotypes. However, this treatment increased the heart and left ventricular to body weight ratios, as well as cardiomyocyte cross-sectional area, and cardiac expression of atrial natriuretic peptide mRNA in mice lacking GCA. Hydralazine did not affect cardiac hypertrophy in wild-type mice and mice lacking either AT1 or AT2 receptors alone. However, the pro-hypertrophic effect of hydralazine was prevented in mice lacking both GCA and AT2, but not GCA and AT1 receptors. However, hydralazine did decrease cardiac collagen deposition and collagen I mRNA (signs of cardiac fibrosis) in mice that were deficient in GCA, or both GCA and AT2 receptors. Conclusions and implications: The vasodilator hydralazine induced AT2 receptor-mediated cardiomyocyte growth under conditions of GCA deficiency. However, attenuation of cardiac fibrosis by hydralazine could be beneficial in the management of cardiac diseases. PMID:20136844

Archean Microbial Mat Communities

NASA Astrophysics Data System (ADS)

Tice, Michael M.; Thornton, Daniel C. O.; Pope, Michael C.; Olszewski, Thomas D.; Gong, Jian

2011-05-01

Much of the Archean record of microbial communities consists of fossil mats and stromatolites. Critical physical emergent properties governing the evolution of large-scale (centimeters to meters) topographic relief on the mat landscape are (a) mat surface roughness relative to the laminar sublayer and (b) cohesion. These properties can be estimated for fossil samples under many circumstances. A preliminary analysis of Archean mat cohesion suggests that mats growing in shallow marine environments from throughout this time had cohesions similar to those of modern shallow marine mats. There may have been a significant increase in mat strength at the end of the Archean.

Metabolic characterization of a mouse deficient in all known leptin receptor isoforms.

PubMed

Osborn, Olivia; Sanchez-Alavez, Manuel; Brownell, Sara E; Ross, Brendon; Klaus, Joe; Dubins, Jeffrey; Beutler, Bruce; Conti, Bruno; Bartfai, Tamas

2010-01-01

We have characterized a newly generated mouse model of obesity, a mouse strain deficient in all five previously described leptin receptor isoforms. These transgenic mice, named the db (333)/db (333) mice, were identified from an ENU mutagenesis screen and carry a point mutation in the seventh exon of the db gene encoding the leptin receptor, resulting in a premature stop codon (Y(333)Stop) and gene product that lacks STAT signaling domains. db (333)/db (333) mice have a morbidly obese phenotype, with body weights diverging from wild type as early as 4 weeks of age (P < 0.05). To determine the contribution of the short isoforms of the leptin receptor in this metabolic phenotype, we performed an extensive metabolic characterization of the db (333)/db (333) mouse in relation to the well-characterized db/db mouse lacking only the long form of the leptin receptor. db (333)/db (333) mice have similar endocrine and metabolic parameters as previously described in other leptin receptor transgenic mice including db/db mice that lack only the long isoform of the leptin receptor. However, db (333)/db (333) mice show a subtle trend toward higher body weight and insulin levels, lower oxygen, carbon dioxide production, respiratory exchange ratio (RER), and temperature than db/db mice suggesting the short isoforms may play an additional role in energy homeostasis.

TERATOGENIC RESPONSES ARE MODULATED IN MICE LACKING EXPRESSION OF EPIDERMAL GROWTH FACTOR (EGF) AND TRANSFORMING GROWTH FACTOR-ALPHA (TGF)

EPA Science Inventory

TITLE:
TERATOGENIC RESPONSES ARE MODULATED IN MICE LACKING EXPRESSION OF EPIDERMAL GROWTH FACTOR (EGF) AND TRANSFORMING GROWTH FACTOR-ALPHA (TGF). AUTHORS (ALL): Abbott, Barbara D.1; Best, Deborah S.1; Narotsky, Michael G.1. SPONSOR NAME: None INSTITUTIONS (ALL): 1. Repro Tox ...

Presence and Functionality of Mating Type Genes in the Supposedly Asexual Filamentous Fungus Aspergillus oryzae

PubMed Central

Wada, Ryuta; Maruyama, Jun-ichi; Yamaguchi, Haruka; Yamamoto, Nanase; Wagu, Yutaka; Paoletti, Mathieu; Archer, David B.; Dyer, Paul S.

2012-01-01

The potential for sexual reproduction in Aspergillus oryzae was assessed by investigating the presence and functionality of MAT genes. Previous genome studies had identified a MAT1-1 gene in the reference strain RIB40. We now report the existence of a complementary MAT1-2 gene and the sequencing of an idiomorphic region from A. oryzae strain AO6. This allowed the development of a PCR diagnostic assay, which detected isolates of the MAT1-1 and MAT1-2 genotypes among 180 strains assayed, including industrial tane-koji isolates. Strains used for sake and miso production showed a near-1:1 ratio of the MAT1-1 and MAT1-2 mating types, whereas strains used for soy sauce production showed a significant bias toward the MAT1-2 mating type. MAT1-1 and MAT1-2 isogenic strains were then created by genetic manipulation of the resident idiomorph, and gene expression was compared by DNA microarray and quantitative real-time PCR (qRT-PCR) methodologies under conditions in which MAT genes were expressed. Thirty-three genes were found to be upregulated more than 10-fold in either the MAT1-1 host strain or the MAT1-2 gene replacement strain relative to each other, showing that both the MAT1-1 and MAT1-2 genes functionally regulate gene expression in A. oryzae in a mating type-dependent manner, the first such report for a supposedly asexual fungus. MAT1-1 expression specifically upregulated an α-pheromone precursor gene, but the functions of most of the genes affected were unknown. The results are consistent with a heterothallic breeding system in A. oryzae, and prospects for the discovery of a sexual cycle are discussed. PMID:22327593

Urinary Concentrations of Polycyclic Aromatic Hydrocarbon Metabolites in Maté Drinkers in Rio Grande do Sul, Brazil

PubMed Central

Lopes, Antonio Barros; Metzdorf, Marcela; Metzdorf, Luiza; Ramalho, Marcos Paulo; Kavalco, Caroline; Etemadi, Arash; Pritchett, Natalie R.; Murphy, Gwen; Calafat, Antonia M.; Abnet, Christian C.; Dawsey, Sanford M.; Fagundes, Renato Borges

2017-01-01

Background Consumption of maté, an infusion of the herb Ilex paraguariensis (yerba maté), is associated with increased risk of esophageal squamous cell carcinoma (ESCC), but the carcinogenic mechanism is unclear. Commercial brands of yerba maté contain high levels of carcinogenic polycyclic aromatic hydrocarbons (PAHs), which are acquired during the traditional drying process. The purpose of this study was to characterize exposure to PAHs in maté drinkers over a wide range of maté consumption. Methods We recruited 244 adults who answered a questionnaire and collected a fasting spot urine specimen. We quantified urinary concentrations of seven PAH metabolites, and assessed associations between self-reported recent maté consumption and urinary PAH metabolites by multivariate regression. Results Recent maté consumption showed a significant dose-response association with 6 of 7 PAH metabolites in unadjusted models (p-for-trend <0.05). After adjustment for creatinine and potential confounders, concentrations of 2-naphthol, 1-hydroxyphenanthrene, and the sum of 2- and 3-hydroxyphenanthrene remained significantly associated with recent maté intake. The sum of the urinary concentrations of the phenanthrene metabolites was similar or higher among maté drinkers who did not smoke than among smokers who did not drink maté. Conclusions Urinary concentrations of PAH metabolites were significantly associated with self-reported amount of recent maté intake, and drinking maté increased urinary concentrations of some PAH metabolites as much as smoking cigarettes. Impact Drinking maté is a source of exposure to potentially carcinogenic PAHs, consistent with the hypothesis that the PAH content of maté may contribute to the increased risk of ESCC in maté drinkers. PMID:29263183

Urinary Concentrations of Polycyclic Aromatic Hydrocarbon Metabolites in Maté Drinkers in Rio Grande do Sul, Brazil.

PubMed

Lopes, Antonio Barros; Metzdorf, Marcela; Metzdorf, Luiza; Sousa, Marcos Paulo Ramalho; Kavalco, Caroline; Etemadi, Arash; Pritchett, Natalie R; Murphy, Gwen; Calafat, Antonia M; Abnet, Christian C; Dawsey, Sanford M; Fagundes, Renato Borges

2018-03-01

Background: Consumption of maté , an infusion of the herb Ilex paraguariensis (yerba maté) , is associated with increased risk of esophageal squamous cell carcinoma (ESCC), but the carcinogenic mechanism is unclear. Commercial brands of yerba maté contain high levels of carcinogenic polycyclic aromatic hydrocarbons (PAHs), which are acquired during the traditional drying process. The purpose of this study was to characterize exposure to PAHs in maté drinkers over a wide range of maté consumption. Methods: We recruited 244 adults who answered a questionnaire and collected a fasting spot urine specimen. We quantified urinary concentrations of seven PAH metabolites and assessed associations between self-reported recent maté consumption and urinary PAH metabolites by multivariate regression. Results: Recent maté consumption showed a significant dose-response association with 6 of 7 PAH metabolites in unadjusted models ( P trend < 0.05). After adjustment for creatinine and potential confounders, concentrations of 2-naphthol, 1-hydroxyphenanthrene, and the sum of 2- and 3-hydroxyphenanthrene remained significantly associated with recent maté intake. The sum of the urinary concentrations of the phenanthrene metabolites was similar or higher among maté drinkers who did not smoke than among smokers who did not drink maté Conclusions: Urinary concentrations of PAH metabolites were significantly associated with self-reported amounts of recent maté intake, and drinking maté increased urinary concentrations of some PAH metabolites as much as smoking cigarettes. Impact: Drinking maté is a source of exposure to potentially carcinogenic PAHs, consistent with the hypothesis that the PAH content of maté may contribute to the increased risk of ESCC in maté drinkers. Cancer Epidemiol Biomarkers Prev; 27(3); 331-7. ©2017 AACR . ©2017 American Association for Cancer Research.

Myelin/oligodendrocyte glycoprotein–deficient (MOG-deficient) mice reveal lack of immune tolerance to MOG in wild-type mice

PubMed Central

Delarasse, Cécile; Daubas, Philippe; Mars, Lennart T.; Vizler, Csaba; Litzenburger, Tobias; Iglesias, Antonio; Bauer, Jan; Della Gaspera, Bruno; Schubart, Anna; Decker, Laurence; Dimitri, Dalia; Roussel, Guy; Dierich, Andrée; Amor, Sandra; Dautigny, André; Liblau, Roland; Pham-Dinh, Danielle

2003-01-01

We studied the immunological basis for the very potent encephalitogenicity of myelin/oligodendrocyte glycoprotein (MOG), a minor component of myelin in the CNS that is widely used to induce experimental autoimmune encephalomyelitis (EAE). For this purpose, we generated a mutant mouse lacking a functional mog gene. This MOG-deficient mouse presents no clinical or histological abnormalities, permitting us to directly assess the role of MOG as a target autoantigen in EAE. In contrast to WT mice, which developed severe EAE following immunization with whole myelin, MOG-deficient mice had a mild phenotype, demonstrating that the anti-MOG response is a major pathogenic component of the autoimmune response directed against myelin. Moreover, while MOG transcripts are expressed in lymphoid organs in minute amounts, both MOG-deficient and WT mice show similar T and B cell responses against the extracellular domain of MOG, including the immunodominant MOG 35–55 T cell epitope. Furthermore, no differences in the fine specificity of the T cell responses to overlapping peptides covering the complete mouse MOG sequence were observed between MOG+/+ and MOG–/– mice. In addition, upon adoptive transfer, MOG-specific T cells from WT mice and those from MOG-deficient mice are equally pathogenic. This total lack of immune tolerance to MOG in WT C57BL/6 mice may be responsible for the high pathogenicity of the anti-MOG immune response as well as the high susceptibility of most animal strains to MOG-induced EAE. PMID:12925695

MatLab Script and Functional Programming

NASA Technical Reports Server (NTRS)

Shaykhian, Gholam Ali

2007-01-01

MatLab Script and Functional Programming: MatLab is one of the most widely used very high level programming languages for scientific and engineering computations. It is very user-friendly and needs practically no formal programming knowledge. Presented here are MatLab programming aspects and not just the MatLab commands for scientists and engineers who do not have formal programming training and also have no significant time to spare for learning programming to solve their real world problems. Specifically provided are programs for visualization. The MatLab seminar covers the functional and script programming aspect of MatLab language. Specific expectations are: a) Recognize MatLab commands, script and function. b) Create, and run a MatLab function. c) Read, recognize, and describe MatLab syntax. d) Recognize decisions, loops and matrix operators. e) Evaluate scope among multiple files, and multiple functions within a file. f) Declare, define and use scalar variables, vectors and matrices.

IgA is Important for Clearance and Critical for Protection from Rotavirus Infection

PubMed Central

Blutt, Sarah E; Miller, Amber D.; Salmon, Sharon L.; Metzger, Dennis W.; Conner, Margaret E

2012-01-01

Based on a lack of severe phenotype in human IgA deficiency syndromes, the role of IgA in controlling respiratory and gastrointestinal (GI) infections has not been clearly defined. C57BL/6 and BALB/c mice lacking IgA (IgA−/−) were developed and used to address this question. When exposed to a common GI virus, rotavirus, IgA−/− mice exhibited a substantial and significant delay in clearance of the initial infection compared to wild type mice. IgA−/− mice excreted rotavirus in stool up to three weeks after the initial exposure compared to ten days observed in wild type mice. Importantly, IgA−/− mice failed to develop protective immunity against multiple repeat exposures to the virus. All IgA−/− mice excreted virus in the stool upon re-exposure to rotavirus while wild type mice were completely protected against re-infection. These findings clearly indicate a critical role for IgA in the establishment of immunity against a GI viral pathogen. PMID:22739233

Testing DNA barcodes in closely related species of Curcuma (Zingiberaceae) from Myanmar and China.

PubMed

Chen, Juan; Zhao, Jietang; Erickson, David L; Xia, Nianhe; Kress, W John

2015-03-01

The genus Curcuma L. is commonly used as spices, medicines, dyes and ornamentals. Owing to its economic significance and lack of clear-cut morphological differences between species, this genus is an ideal case for developing DNA barcodes. In this study, four chloroplast DNA regions (matK, rbcL, trnH-psbA and trnL-F) and one nuclear region (ITS2) were generated for 44 Curcuma species and five species from closely related genera, represented by 96 samples. PCR amplification success rate, intra- and inter-specific genetic distance variation and the correct identification percentage were taken into account to assess candidate barcode regions. PCR and sequence success rate were high in matK (89.7%), rbcL (100%), trnH-psbA (100%), trnL-F (95.7%) and ITS2 (82.6%) regions. The results further showed that four candidate chloroplast barcoding regions (matK, rbcL, trnH-psbA and trnL-F) yield no barcode gaps, indicating that the genus Curcuma represents a challenging group for DNA barcoding. The ITS2 region presented large interspecific variation and provided the highest correct identification rates (46.7%) based on BLASTClust method among the five regions. However, the ITS2 only provided 7.9% based on NJ tree method. An increase in discriminatory power needs the development of more variable markers. © 2014 John Wiley & Sons Ltd.

Fabrication and In Vitro/In Vivo Performance of Mucoadhesive Electrospun Nanofiber Mats Containing α-Mangostin.

PubMed

Samprasit, Wipada; Rojanarata, Theerasak; Akkaramongkolporn, Prasert; Ngawhirunpat, Tanasait; Kaomongkolgit, Ruchadaporn; Opanasopit, Praneet

2015-10-01

This study aimed to fabricate mucoadhesive electrospun nanofiber mats containing α-mangostin for the maintenance of oral hygiene and reduction of the bacterial growth that causes dental caries. Synthesized thiolated chitosan (CS-SH) blended with polyvinyl alcohol (PVA) was selected as the mucoadhesive polymer. α-Mangostin was incorporated into the CS-SH/PVA solution and electrospun to obtain nanofiber mats. Scanning electron microscopy, differential scanning calorimetry, X-ray diffraction, and tensile strength testing were used to characterize the mats. The swelling degree and mucoadhesion were also determined. The nanofiber mats were further evaluated regarding their α-mangostin content, in vitro α-mangostin release, antibacterial activity, cytotoxicity, in vivo performance, and stability. The results indicated that the mats were in the nanometer range. The α-mangostin was well incorporated into the mats, with an amorphous form. The mats showed suitable tensile strength, swelling, and mucoadhesive properties. The loading capacity increased when the initial amount of α-mangostin was increased. Rapid release of α-mangostin from the mats was achieved. Additionally, a fast bacterial killing rate occurred at the lowest concentration of nanofiber mats when α-mangostin was added to the mats. The mats were less cytotoxic after use for 72 h. Moreover, in vivo testing indicated that the mats could reduce the number of oral bacteria, with a good mouth feel. The mats maintained the amount of α-mangostin for 6 months. The results suggest that α-mangostin-loaded mucoadhesive electrospun nanofiber mats may be a promising material for oral care and the prevention of dental caries.

Role of Interleukin-1 Receptor Signaling in the Behavioral Effects of Ethanol and Benzodiazepines

PubMed Central

Blednov, Yuri A.; Benavidez, Jillian M.; Black, Mendy; Mayfield, Jody; Harris, R. Adron

2015-01-01

Gene expression studies identified the interleukin-1 receptor type I (IL-1R1) as part of a pathway associated with a genetic predisposition to high alcohol consumption, and lack of the endogenous IL-1 receptor antagonist (IL-1ra) strongly reduced ethanol intake in mice. Here, we compared ethanol-mediated behaviors in mice lacking Il1rn or Il1r1. Deletion of Il1rn (the gene encoding IL-1ra) increases sensitivity to the sedative/hypnotic effects of ethanol and flurazepam and reduces severity of acute ethanol withdrawal. Conversely, deletion of Il1r1 (the gene encoding the IL-1 receptor type I, IL-1R1) reduces sensitivity to the sedative effects of ethanol and flurazepam and increases the severity of acute ethanol withdrawal. The sedative effects of ketamine and pentobarbital were not altered in the knockout (KO) strains. Ethanol intake and preference were not changed in mice lacking Il1r1 in three different tests of ethanol consumption. Recovery from ethanol-induced motor incoordination was only altered in female mice lacking Il1r1. Mice lacking Il1rn (but not Il1r1) showed increased ethanol clearance and decreased ethanol-induced conditioned taste aversion. The increased ethanol- and flurazepam-induced sedation in Il1rn KO mice was decreased by administration of IL-1ra (Kineret), and pre-treatment with Kineret also restored the severity of acute ethanol withdrawal. Ethanol-induced sedation and withdrawal severity were changed in opposite directions in the null mutants, indicating that these responses are likely regulated by IL-1R1 signaling, whereas ethanol intake and preference do not appear to be solely regulated by this pathway. PMID:25839897

Role of interleukin-1 receptor signaling in the behavioral effects of ethanol and benzodiazepines.

PubMed

Blednov, Yuri A; Benavidez, Jillian M; Black, Mendy; Mayfield, Jody; Harris, R Adron

2015-08-01

Gene expression studies identified the interleukin-1 receptor type I (IL-1R1) as part of a pathway associated with a genetic predisposition to high alcohol consumption, and lack of the endogenous IL-1 receptor antagonist (IL-1ra) strongly reduced ethanol intake in mice. Here, we compared ethanol-mediated behaviors in mice lacking Il1rn or Il1r1. Deletion of Il1rn (the gene encoding IL-1ra) increases sensitivity to the sedative/hypnotic effects of ethanol and flurazepam and reduces severity of acute ethanol withdrawal. Conversely, deletion of Il1r1 (the gene encoding the IL-1 receptor type I, IL-1R1) reduces sensitivity to the sedative effects of ethanol and flurazepam and increases the severity of acute ethanol withdrawal. The sedative effects of ketamine and pentobarbital were not altered in the knockout (KO) strains. Ethanol intake and preference were not changed in mice lacking Il1r1 in three different tests of ethanol consumption. Recovery from ethanol-induced motor incoordination was only altered in female mice lacking Il1r1. Mice lacking Il1rn (but not Il1r1) showed increased ethanol clearance and decreased ethanol-induced conditioned taste aversion. The increased ethanol- and flurazepam-induced sedation in Il1rn KO mice was decreased by administration of IL-1ra (Kineret), and pre-treatment with Kineret also restored the severity of acute ethanol withdrawal. Ethanol-induced sedation and withdrawal severity were changed in opposite directions in the null mutants, indicating that these responses are likely regulated by IL-1R1 signaling, whereas ethanol intake and preference do not appear to be solely regulated by this pathway. Copyright © 2015 Elsevier Ltd. All rights reserved.

ERB master archival tape specification no. T 134081 ERB MAT, revision 1

NASA Technical Reports Server (NTRS)

1984-01-01

The Earth radiation budget (ERB)MAT tapes are generated by the ERB MATGEN software using the IBM 3081 computer system operated by the Science and Applications Computer Center at Goddard Space Flight Center. All MAT's are 9-track and MAT data are in ascending time order. The gross tape format for NIMBUS year-1 and year-2 MAT's is different from the format of MAT's starting with year-3. The MATs from the first two years are to contain one day's worth of data while all other MATs are to contain multiple day's worth of data stacked onto the tapes.

Maternal inheritance of mitochondria: multipolarity, multiallelism and hierarchical transmission of mitochondrial DNA in the true slime mold Physarum polycephalum.

PubMed

Moriyama, Yohsuke; Kawano, Shigeyuki

2010-03-01

Direct evidence of digestion of paternal mitochondrial DNA (mtDNA) has been found in the true slime mold Physarum polycephalum. This is the first report on the selective digestion of mtDNA inside the zygote, and is striking evidence for the mechanism of maternal inheritance of mitochondria. Moreover, two mitochondrial nuclease activities were detected in this organism as-candidates for the nucleases responsible for selective digestion of mtDNA. In the true slime mold, there is an additional-feature of the uniparental inheritance of mitochondria.Although mitochondria are believed to be inherited from the maternal lineage in nearly all eukaryotes, the mating types of the true slime mold P. polycephalum is not restricted to two: there are three mating loci--matA, matB,and matC--and these loci have 16, 15, and 3 alleles,-respectively. Interestingly, the transmission patterns of mtDNA are determined by the matA locus, in a hierarchical-fashion (matA hierarchy) as follows: matA7[matA2[matA11[matA12[matA15/matA16[matA1[matA6.The strain possessing the higher status of matA would be the mtDNA donor in crosses. Furthermore, we have found that some crosses showed biparental inheritance of mitochondria.This review describes the phenomenon of hierarchical transmission of mtDNA in true slime molds, and discusses the presumed molecular mechanism of maternal and biparental inheritance.

MatMRI and MatHIFU: software toolboxes for real-time monitoring and control of MR-guided HIFU

PubMed Central

2013-01-01

Background The availability of open and versatile software tools is a key feature to facilitate pre-clinical research for magnetic resonance imaging (MRI) and magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) and expedite clinical translation of diagnostic and therapeutic medical applications. In the present study, two customizable software tools that were developed at the Thunder Bay Regional Research Institute are presented for use with both MRI and MR-HIFU. Both tools operate in a MATLAB®; environment. The first tool is named MatMRI and enables real-time, dynamic acquisition of MR images with a Philips MRI scanner. The second tool is named MatHIFU and enables the execution and dynamic modification of user-defined treatment protocols with the Philips Sonalleve MR-HIFU therapy system to perform ultrasound exposures in MR-HIFU therapy applications. Methods MatMRI requires four basic steps: initiate communication, subscribe to MRI data, query for new images, and unsubscribe. MatMRI can also pause/resume the imaging and perform real-time updates of the location and orientation of images. MatHIFU requires four basic steps: initiate communication, prepare treatment protocol, and execute treatment protocol. MatHIFU can monitor the state of execution and, if required, modify the protocol in real time. Results Four applications were developed to showcase the capabilities of MatMRI and MatHIFU to perform pre-clinical research. Firstly, MatMRI was integrated with an existing small animal MR-HIFU system (FUS Instruments, Toronto, Ontario, Canada) to provide real-time temperature measurements. Secondly, MatMRI was used to perform T2-based MR thermometry in the bone marrow. Thirdly, MatHIFU was used to automate acoustic hydrophone measurements on a per-element basis of the 256-element transducer of the Sonalleve system. Finally, MatMRI and MatHIFU were combined to produce and image a heating pattern that recreates the word ‘HIFU’ in a tissue-mimicking heating phantom. Conclusions MatMRI and MatHIFU leverage existing MRI and MR-HIFU clinical platforms to facilitate pre-clinical research. MatMRI substantially simplifies the real-time acquisition and processing of MR data. MatHIFU facilitates the testing and characterization of new therapy applications using the Philips Sonalleve clinical MR-HIFU system. Under coordination with Philips Healthcare, both MatMRI and MatHIFU are intended to be freely available as open-source software packages to other research groups. PMID:25512856

A balance between TFPI and thrombin-mediated platelet activation is required for murine embryonic development

PubMed Central

Ellery, Paul E. R.; Maroney, Susan A.; Cooley, Brian C.; Luyendyk, James P.; Zogg, Mark; Weiler, Hartmut

2015-01-01

Tissue factor pathway inhibitor (TFPI) is a critical anticoagulant protein present in endothelium and platelets. Mice lacking TFPI (Tfpi−/−) die in utero from disseminated intravascular coagulation. They are rescued by concomitant tissue factor (TF) deficiency, demonstrating that TFPI modulates TF function in vivo. Recent studies have found TFPI inhibits prothrombinase activity during the initiation of coagulation and limits platelet accumulation during thrombus formation, implicating TFPI in modulating platelet procoagulant activity. To examine whether altered platelet function would compensate for the lack of TFPI and rescue TFPI-null embryonic lethality, Tfpi+/− mice lacking the platelet thrombin receptor, protease activated receptor 4 (PAR4; Par4−/−), or its coreceptor, PAR3, were mated. PAR3 deficiency did not rescue Tfpi−/− embryos, but >40% of expected Tfpi−/−:Par4−/− offspring survived to adulthood. Adult Tfpi−/−:Par4−/− mice did not exhibit overt thrombosis. However, they had focal sterile inflammation with fibrin(ogen) deposition in the liver and elevated plasma thrombin-antithrombin complexes, indicating activation of coagulation at baseline. Tfpi−/−:Par4−/− mice have platelet and fibrin accumulation similar to Par4−/− mice following venous electrolytic injury but were more susceptible than Par4−/− mice to TF-induced pulmonary embolism. In addition, ∼30% of the Tfpi−/−:Par4−/− mice were born with short tails. Tfpi−/−:Par4−/− mice are the first adult mice described that lack TFPI with unaltered TF. They demonstrate that TFPI physiologically modulates thrombin-dependent platelet activation in a manner that is required for successful embryonic development and identify a role for TFPI in dampening intravascular procoagulant stimuli that lead to thrombin generation, even in the absence of thrombin-mediated platelet activation. PMID:25954015

Are floating algal mats a refuge from hypoxia for estuarine invertebrates?

PubMed Central

Knysh, Kyle M.; Theriault, Emma F.; Pater, Christina C.; Courtenay, Simon C.; van den Heuvel, Michael R.

2017-01-01

Eutrophic aquatic habitats are characterized by the proliferation of vegetation leading to a large standing biomass that upon decomposition may create hypoxic (low-oxygen) conditions. This is indeed the case in nutrient impacted estuaries of Prince Edward Island, Canada, where macroalgae, from the genus Ulva, form submerged ephemeral mats. Hydrological forces and gases released from photosynthesis and decomposition lead to these mats occasionally floating to the water’s surface, henceforth termed floating mats. Here, we explore the hypothesis that floating mats are refugia during periods of sustained hypoxia/anoxia and examine how the invertebrate community responds to it. Floating mats were not always present, so in the first year (2013) sampling was attempted monthly and limited to when both floating and submerged mats occurred. In the subsequent year sampling was weekly, but at only one estuary due to logistical constraints from increased sampling frequency, and was not limited to when both mat types occurred. Water temperature, salinity, and pH were monitored bi-weekly with dissolved oxygen concentration measured hourly. The floating and submerged assemblages shared many of the same taxa but were statistically distinct communities; submerged mats tended to have a greater proportion of benthic animals and floating mats had more mobile invertebrates and insects. In 2014, sampling happened to occur in the weeks before the onset of anoxia, during 113 consecutive hours of sustained anoxia, and for four weeks after normoxic conditions returned. The invertebrate community on floating mats appeared to be unaffected by anoxia, indicating that these mats may be refugia during times of oxygen stress. Conversely, there was a dramatic decrease in animal abundances that remained depressed on submerged mats for two weeks. Cluster analysis revealed that the submerged mat communities from before the onset of anoxia and four weeks after anoxia were highly similar to each other, indicating recovery. When mobile animals were considered alone, there was an exponential relationship between the percentage of animals on floating mats, relative to the total number on both mat types, and hypoxia. The occupation of floating mats by invertebrates at all times, and their dominance there during hypoxia/anoxia, provides support for the hypothesis that floating mats are refugia. PMID:28348927

The Effects of Low Sulfate Concentrations on Modern Microbial Mat Communities: A Long Term Manipulation

NASA Technical Reports Server (NTRS)

Bebout, Brad; Carpenter, Steve; DesMarais, David J.; Discipulo, Mykell; Hogan, Mary; Turk, Kendra

2002-01-01

Microbial mats were widespread during the first ca. 2 Ga. of our biosphere's history. To better understand microbial ecosystems and their biomarkers under the low sulfate levels present in early oceans, we attempted a long-term (ca. 1 year) manipulation of sulfate in modem mats. Mats collected from salt ponds at Guerrero Negro, Baja Calif. Sur were incubated in a Greenhouse "Collaboratory" at Ames. Mats were maintained in artificial seawater brine containing either: 1) sulfate levels normal for these mats (70 mM), or 2) brine in which sulfate was replaced by chloride. Sulfate concentrations in the "low sulfate" brine gradually approached their lowest (to date) value of 0. 1 mM as sulfate was consumed and/or diffused out of the mat over a period of ca. 4 months. During that period of time, a number of differences between the treatments emerged. Relative to the "low sulfate" mats, "normal sulfate" mats had: 1) lower consumption of oxygen in the lower levels of the mat, 2) higher efficiencies of oxygenic photosynthesis, and 3) higher rates of nitrogen fixation. Rates of methane production by the mats increased greatly as sulfate concentrations fell below ca. 0.2 mM. In contrast, "low" and "normal" sulfate mats had similar net rates of exchange of O2 and dissolved inorganic C between the mats and overlying water. Reduced sulfate levels have diverse impacts upon these ecosystems.

Deletion and Complementation of the Mating Type (MAT) Locus of the Wheat Head Blight Pathogen Gibberella zeae

PubMed Central

Desjardins, A. E.; Brown, D. W.; Yun, S.-H.; Proctor, R. H.; Lee, T.; Plattner, R. D.; Lu, S.-W.; Turgeon, B. G.

2004-01-01

Gibberella zeae, a self-fertile, haploid filamentous ascomycete, causes serious epidemics of wheat (Triticum aestivum) head blight worldwide and contaminates grain with trichothecene mycotoxins. Anecdotal evidence dating back to the late 19th century indicates that G. zeae ascospores (sexual spores) are a more important inoculum source than are macroconidia (asexual spores), although the fungus can produce both during wheat head blight epidemics. To develop fungal strains to test this hypothesis, the entire mating type (MAT1) locus was deleted from a self-fertile (MAT1-1/MAT1-2), virulent, trichothecene-producing wild-type strain of G. zeae. The resulting MAT deletion (mat1-1/mat1-2) strains were unable to produce perithecia or ascospores and appeared to be unable to mate with the fertile strain from which they were derived. Complementation of a MAT deletion strain by transformation with a copy of the entire MAT locus resulted in recovery of production of perithecia and ascospores. MAT deletion strains and MAT-complemented strains retained the ability to produce macroconidia that could cause head blight, as assessed by direct injection into wheat heads in greenhouse tests. Availability of MAT-null and MAT-complemented strains provides a means to determine the importance of ascospores in the biology of G. zeae and perhaps to identify novel approaches to control wheat head blight. PMID:15066842

Effect of Bathroom Aids and Age on Balance Control During Bathing Transfers.

PubMed

King, Emily C; Novak, Alison C

Bathroom assistive devices are used to improve safety during bathing transfers, but biomechanical evidence to support clinical recommendations is lacking. This study evaluated the effectiveness of common bathroom aids in promoting balance control during bathing transfers. Twenty-six healthy adults (12 young, 14 older) stepped into and out of a slippery bathtub while using a vertical grab bar on the side wall, a horizontal grab bar on the back wall, a bath mat, a side wall touch, or no assistance. Balance control was characterized using center of pressure measures and showed greater instability for older adults. The vertical grab bar and wall touch resulted in the safest (best controlled) transfers. The bath mat provided improved balance control in the axis parallel to the bathtub rim but was equivalent to no assistance perpendicular to the rim, in the direction of obstacle crossing. These results can support clinical recommendations for safe bathing transfers. Copyright © 2017 by the American Occupational Therapy Association, Inc.

Comparative Metagenomics of the Polymicrobial Black Band Disease of Corals

PubMed Central

Meyer, Julie L.; Paul, Valerie J.; Raymundo, Laurie J.; Teplitski, Max

2017-01-01

Black Band Disease (BBD), the destructive microbial consortium dominated by the cyanobacterium Roseofilum reptotaenium, affects corals worldwide. While the taxonomic composition of BBD consortia has been well-characterized, substantially less is known about its functional repertoire. We sequenced the metagenomes of Caribbean and Pacific black band mats and cultured Roseofilum and obtained five metagenome-assembled genomes (MAGs) of Roseofilum, nine of Proteobacteria, and 12 of Bacteroidetes. Genomic content analysis suggests that Roseofilum is a source of organic carbon and nitrogen, as well as natural products that may influence interactions between microbes. Proteobacteria and Bacteroidetes members of the disease consortium are suited to the degradation of amino acids, proteins, and carbohydrates. The accumulation of sulfide underneath the black band mat, in part due to a lack of sulfur oxidizers, contributes to the lethality of the disease. The presence of sulfide:quinone oxidoreductase genes in all five Roseofilum MAGs and in the MAGs of several heterotrophs demonstrates that resistance to sulfide is an important characteristic for members of the BBD consortium. PMID:28458657

Flight Test of Advanced Digital Control Concepts.

DTIC Science & Technology

1982-03-01

34 equations, and this result is then compared against the "model" equations. OPTION :::CREATrE ,CIEY, COFPY, MAT ,AMAT, COIP-YUMAT, BMAT , 74 COPFY, CMAT...BMATY .-COPY, NMAT, AMAT ,72 ,COPY, GMAT, RMA, COP:Y, (MAT, BMA’TCOFY, MA T ,AMAT >74, COPY, CMA’TsmA, PCOPY, RMAT, BmAT , pCOPYVMiAT , AMAo.T 72...COP’Y, MAT, AMAT, >75, COPY , MAtT, BMAT , COPY, ZMAT, AMAT, 74 ,COP’Y, MAT, TMAT, COPY, VMAT, AMAT, .:COPY ,RMAiT, MAT,73,COPW GMAT, E4MAT, COP-"YTMAT

Fe-oxidizing microbes are hydrothermal vent ecosystem engineers at the Loihi Seamount (Invited)

NASA Astrophysics Data System (ADS)

Chan, C. S.; McAllister, S.; Leavitt, A.; Emerson, D.; Moyer, C. L.; Glazer, B. T.

2013-12-01

Microaerophilic Fe-oxidizing microorganisms (FeOM) colonize gradients of Fe(II) and oxygen, taking advantage of the available chemical energy. Vast communities of FeOM proliferate at deep sea hydrothermal vents, forming mineralized mats that range from centimeters to meters thick. Because these mats structure the environment for both FeOM and the entire microbial community, the Fe-oxidizers are acting as ecosystem engineers. What organisms are responsible for initiating these mats, and how does the physical structure and community composition develop as the mats mature? By connecting structure, function, and ecology, we can better interpret modern mat structures, as well as ancient fossilized mats. We have been studying Fe microbial mats at Loihi Seamount in Hawaii, a long-term study site that has become a model for Fe oxidation in marine hydrothermal systems. Recent improvements in ROV imaging systems allow us to see a great range of mat textures and colors, which may represent diverse habitats and/or different stages of mat development. With improved imaging and sampling techniques, we have been able to obtain discrete, intact samples of these delicate microbial mats. Previous bulk sampling methods showed that mats consist of a mixture of Fe-mineralized morphologies. Our analyses of intact mats show that mats are initiated by one type of structure-former (either a stalk-former like Mariprofundus ferrooxydans or a Zetaproteobacterial sheath-former). These microbes may be the vanguard organisms that stabilize chemical gradients in this dynamic environment, allowing colonization by other organisms (evidenced by branching tubes, fibrillar nests, and other morphologies). We will show evidence of the composition and development of these mats, and discuss parallels between these marine Fe mats and their freshwater counterparts, supporting the idea that FeOM engineer environments favorable for growth.

Biocompatibility of electrospun human albumin: a pilot study.

PubMed

Noszczyk, B H; Kowalczyk, T; Łyżniak, M; Zembrzycki, K; Mikułowski, G; Wysocki, J; Kawiak, J; Pojda, Z

2015-03-02

Albumin is rarely used for electrospinning because it does not form fibres in its native globular form. This paper presents a novel method for electrospinning human albumin from a solution containing pharmaceutical grade protein and 25% polyethylene oxide (PEO) used as the fibre-forming agent. After spontaneous cross-linking at body temperature, with no further chemicals added, the fibres become insoluble and the excess PEO can be washed out. Albumin deposited along the fibres retains its native characteristics, such as its non-adhesiveness to cells and its susceptibility for degradation by macrophages. To demonstrate this we evaluated the mechanical properties, biocompatibility and biodegradability of this novel product. After subcutaneous implantation in mice, albumin mats were completely resorbable within six days and elicited only a limited local inflammatory response. In vitro, the mats suppressed cell attachment and migration. As this product is inexpensive, produced from human pharmaceutical grade albumin without chemical modifications, retains its native protein properties and fulfils the specific requirements for anti-adhesive dressings, its clinical use can be expedited. We believe that it could specifically be used when treating paediatric patients with epidermolysis bullosa, in whom non-healing wounds occur after minor hand injuries which lead to rapid adhesions and devastating contractures.

Foam-mat drying technology: A review.

PubMed

Hardy, Z; Jideani, V A

2017-08-13

This article reviews various aspects of foam-mat drying such as foam-mat drying processing technique, main additives used for foam-mat drying, foam-mat drying of liquid and solid foods, quality characteristics of foam-mat dried foods, and economic and technical benefits for employing foam-mat drying. Foam-mat drying process is an alternative method that allows the removal of water from liquid materials and pureed materials. In this drying process, a liquid material is converted into foam that is stable by being whipped after adding an edible foaming agent. The stable foam is then spread out in sheet or mat and dried by using hot air (40-90°C) at atmospheric pressure. Methyl cellulose (0.25-2%), egg white (3-20%), maltodextrin (0.5-05%), and gum Arabic (2-9%) are the commonly utilized additives for the foam-mat drying process at the given range, either combined together for their effectiveness or individual effect. The foam-mat drying process is suitable for heat sensitive, viscous, and sticky products that cannot be dried using other forms of drying methods such as spray drying because of the state of product. More interest has developed for foam-mat drying because of the simplicity, cost effectiveness, high speed drying, and improved product quality it provides.

Ecophysiological Changes in Microbial Mats Incubated in a Greenhouse Collaboratory

NASA Technical Reports Server (NTRS)

Bebout, Brad; DesMarais, David J.; GarciaPichel, Ferran; Hogan, Mary; Jahnke, Linda; Keller, Richard M.; Miller, Scott R.

2001-01-01

Microbial mats are modern examples of the earliest microbial communities known. Among the best studied are microbial mats growing in hypersaline ponds managed for the production of salt by Exportadora de Sal, S.A. de C.V., Guerrero Negro, Baja California Sur, Mexico. In May, 2001, we collected mats from Ponds 4 and 5 in this system and returned them to Ames Research Center, where they have been maintained for a period of over nine months. We report here on both the ecophysiological changes occurring in the mats over that period of time as well as the facility in which they were incubated. Mats (approximately 1 sq. meter total area) were incubated in a greenhouse facility modified to provide the mats with natural levels of visible and ultraviolet radiation as well as constantly flowing, temperature-controlled water. Two replicated treatments were maintained, a 'high salinity' treatment (about 120 ppt) and a 'low salinity' treatment (about 90 ppt). Rates of net biological activity (e.g., photosynthesis, respiration, trace gas production) in the mats were relatively constant over the several months, and were similar to rates of activity measured in the field. However, over the course of the incubation, mats in both treatments changed in physical appearance. The most obvious change was that mats in the higher salinity treatments developed a higher proportion of carotenoid pigments (relative to chlorophyll), resulting in a noticeably orange color in the high salinity mats. This trend is also seen in the natural salinity gradient present at the field site. Changes in the community composition of the mats, as assayed by denaturing gradient gel electrophoresis (DGGE), as well as biomarker compounds produced in the mats were also monitored. The degree to which the mats kept in the greenhouse changed from the originally collected mats, as well as differences between high and low salinity mats will be discussed. Additional information is contained in the original extended abstract.

Dynamics of archaea at fine spatial scales in Shark Bay mat microbiomes

NASA Astrophysics Data System (ADS)

Wong, Hon Lun; Visscher, Pieter T.; White, Richard Allen, III; Smith, Daniela-Lee; Patterson, Molly M.; Burns, Brendan P.

2017-04-01

The role of archaea in microbial mats is poorly understood. Delineating the spatial distribution of archaea with mat depth will enable resolution of putative niches in these systems. In the present study, high throughput amplicon sequencing was undertaken in conjunction with analysis of key biogeochemical properties of two mats (smooth and pustular) from Shark Bay, Australia. One-way analysis of similarity tests indicated the archaeal community structures of smooth and pustular mats were significantly different (global R = 1, p = 0.1%). Smooth mats possessed higher archaeal diversity, dominated by Parvarchaeota. The methanogenic community in smooth mats was dominated by hydrogenotrophic Methanomicrobiales, as well as methylotrophic Methanosarcinales, Methanococcales, Methanobacteriales and Methanomassiliicoccaceae. Pustular mats were enriched with Halobacteria and Parvarchaeota. Key metabolisms (bacterial and archaeal) were measured, and the rates of oxygen production/consumption and sulfate reduction were up to four times higher in smooth than in pustular mats. Methane production peaked in the oxic layers and was up to seven-fold higher in smooth than pustular mats. The finding of an abundance of anaerobic methanogens enriched at the surface where oxygen levels were highest, coupled with peak methane production in the oxic zone, suggests putative surface anoxic niches in these microbial mats.

Inversion of the chromosomal region between two mating type loci switches the mating type in Hansenula polymorpha.

PubMed

Maekawa, Hiromi; Kaneko, Yoshinobu

2014-11-01

Yeast mating type is determined by the genotype at the mating type locus (MAT). In homothallic (self-fertile) Saccharomycotina such as Saccharomyces cerevisiae and Kluveromyces lactis, high-efficiency switching between a and α mating types enables mating. Two silent mating type cassettes, in addition to an active MAT locus, are essential components of the mating type switching mechanism. In this study, we investigated the structure and functions of mating type genes in H. polymorpha (also designated as Ogataea polymorpha). The H. polymorpha genome was found to harbor two MAT loci, MAT1 and MAT2, that are ∼18 kb apart on the same chromosome. MAT1-encoded α1 specifies α cell identity, whereas none of the mating type genes were required for a identity and mating. MAT1-encoded α2 and MAT2-encoded a1 were, however, essential for meiosis. When present in the location next to SLA2 and SUI1 genes, MAT1 or MAT2 was transcriptionally active, while the other was repressed. An inversion of the MAT intervening region was induced by nutrient limitation, resulting in the swapping of the chromosomal locations of two MAT loci, and hence switching of mating type identity. Inversion-deficient mutants exhibited severe defects only in mating with each other, suggesting that this inversion is the mechanism of mating type switching and homothallism. This chromosomal inversion-based mechanism represents a novel form of mating type switching that requires only two MAT loci.

Learned arbitrary responses to light in mice without rods or cones

NASA Astrophysics Data System (ADS)

Mrosovsky, N.; Salmon, Peggy

2002-10-01

The aim of this investigation was to discover whether mice lacking classical photoreceptors (rods and cones) can nevertheless be trained to respond to light. Mice with the coneless (cl) transgene have an attenuated diphtheria toxin fused to a cone opsin promotor. Mutant mice homozygous for the retinal degeneration (rd) gene undergo loss of their rods. By mating these two strains, mice lacking both cones and rods can be generated (Lucas et al. 1999). Such coneless-rodless mice were able to use light as a signal to make a behavioural response to avoid impending shock. Nevertheless, especially initially, they used the light as a cue less often than wildtype controls, indicating that normally the rods and cones are used for such responses. However, other photoreceptors are able to take over this role to some extent. When the lights were covered with opaque material, the performance of rodless-coneless mice dropped to chance level, indicating that they had been using the light as a cue for avoidance.

Melanopsin is required for non-image-forming photic responses in blind mice.

PubMed

Panda, Satchidananda; Provencio, Ignacio; Tu, Daniel C; Pires, Susana S; Rollag, Mark D; Castrucci, Ana Maria; Pletcher, Mathew T; Sato, Trey K; Wiltshire, Tim; Andahazy, Mary; Kay, Steve A; Van Gelder, Russell N; Hogenesch, John B

2003-07-25

Although mice lacking rod and cone photoreceptors are blind, they retain many eye-mediated responses to light, possibly through photosensitive retinal ganglion cells. These cells express melanopsin, a photopigment that confers this photosensitivity. Mice lacking melanopsin still retain nonvisual photoreception, suggesting that rods and cones could operate in this capacity. We observed that mice with both outer-retinal degeneration and a deficiency in melanopsin exhibited complete loss of photoentrainment of the circadian oscillator, pupillary light responses, photic suppression of arylalkylamine-N-acetyltransferase transcript, and acute suppression of locomotor activity by light. This indicates the importance of both nonvisual and classical visual photoreceptor systems for nonvisual photic responses in mammals.

Molecular Ecological and Stable Isotopic Studies of Nitrogen Fixation in Modern Microbial Mats

NASA Technical Reports Server (NTRS)

Bebout, B. M.; Crumbliss, L. L.; DesMarais, D. J.; Hogan, M. E.; Omoregie, E.; Turk, K. A.; Zehr, J. P.

2003-01-01

Nitrogen is usually the element limiting biological productivity in the marine environment. Microbial mats, laminated microbial communities analogous to some of the oldest forms of life on Earth, are often the sites of high rates of N fixation (the energetically expensive conversion of atmospheric dinitrogen into a biologically useful form). The N fixing enzyme nitrogenase is generally considered to be of ancient origin, and is widely distributed throughout the Bacterial and Archaeal domains of life, indicating an important role for this process over evolutionary time. The stable isotopic signature of N fixation is purportedly recognizable in organic matter (ancient kerogens as well as present-day microbial mats) as a delta (15)N(sub organic) near zero. We studied two microbial mats exhibiting different rates of N fixation in order to better understand the impact of N fixation on the delta (15)N (sub organic) of the mats, as well as what organisms are important in this process. Mats dominated by the cyanobacterium Microcoleus chthonoplastes grow in permanently submerged hypersaline salterns, and exhibit low rates of N fixation, whereas mats dominated by the cyanobacterium Lyngbya spp grow in an intertidal area, and exhibit rates of N fixation an order of magnitude higher. To examine successional stages in mat growth, both developing and established mats at each location were sampled. PCR and RT-PCR based approaches were used to identify, respectively, the organisms containing nifH (one of the genes that encode nitrogenase) as well as those expressing nifH in these mats. Both mats exhibited a distinct diel cycle of N fixation, with highest rates occurring at night. The delta (15)N(sub organic) of the subtidal Microcoleus mats is near zero whereas the delta (15)N(sub organic) is slightly more positive (+ 2-3%), in the intertidal Lyngbya mats, an interesting difference in view of the fact that overall rates of activity in the intertidal mats are much higher that those in the submerged hypersaline mats. Developing mats in both the subtidal and intertidal locations had delta (15)N(sub organic) values very near those of the established mats. Further work is necessary in order to determine the importance of other transformations of nitrogen on the delta (15)N(sub organic) signature of the mats.

Flow-induced Development of Unicellular Cyanobacterial Mats

NASA Astrophysics Data System (ADS)

Gong, J.; Tice, M. M.

2011-12-01

Microbial mats/biofilms are abundant microbial growth structures throughout the history of life on Earth. Understanding the mechanisms for their morphogenesis and interactions with physical sedimentary forces are important topics that allow deeper understanding of related records. When subjected to hydrodynamic influences, mats are known to vary in morphology and structure in response to fluid shear, yet mechanistically, the underlying cellular architecture due to interactions with flow remain unexplained. Moreover, mats are found to emerge larger scale roughness elements and modified cohesive strength growing under flow. It is a mystery how and why these mat-community-level features are linked in association with modified boundary layers at the mats surface. We examined unicellular cyanobacterium Synechocystis sp. PCC 6803 in a circular flow bioreactor designed to maintain a fixed set of hydrodynamic conditions. The use of monoculture strains and unidirectional currents, while not replicating natural mat systems (almost certainly multi-species and often multi-directional currents under complex wind or tidal wave actions), helps to simplify these systems and allows for specific testing of hypotheses regarding how mats evolve distinctive morphologies induced by flow. The unique design of the reactor also makes measurements such as critical erosional shear stress of the mats possible, in addition to microscopic, macroscopic imaging and weeks of continuous mats growth monitoring. We report the finding that linear chains, filament-like cell groups were present from unicellular cyanobacterial mats growing under flow (~1-5 cm/s) and these structures are organized within ~1-3mm size streamers and ~0.5-1mm size nodular macrostructures. Ultra-small, sub-micron thick EPS strings are observed under TEM and are likely the cohesive architectural elements in mats across different fluid regimes. Mat cohesion generally grows with and adapts to increasing flow shear stress within certain limits. Overall topological roughness of the mats were analyzed and estimated in terms of the skin friction of the mats surfaces interacting with flow. Then, together with the critical erosional cohesive strength of the mats estimated, we present a theoretical physical model linking morphology and material strength of mats to overlying fluid flow. If this model were further tested true, it suggests that physical flows may very well have a controlling effect on the properties of mats growing within it.

Expansion of the lateral ventricles and ependymal deficits underlie the hydrocephalus evident in mice lacking the transcription factor NFIX.

PubMed

Vidovic, Diana; Harris, Lachlan; Harvey, Tracey J; Evelyn Heng, Yee Hsieh; Smith, Aaron G; Osinski, Jason; Hughes, James; Thomas, Paul; Gronostajski, Richard M; Bailey, Timothy L; Piper, Michael

2015-08-07

Nuclear factor one X (NFIX) has been shown to play a pivotal role during the development of many regions of the brain, including the neocortex, the hippocampus and the cerebellum. Mechanistically, NFIX has been shown to promote neural stem cell differentiation through the activation of astrocyte-specific genes and via the repression of genes central to progenitor cell self-renewal. Interestingly, mice lacking Nfix also exhibit other phenotypes with respect to development of the central nervous system, and whose underlying causes have yet to be determined. Here we examine one of the phenotypes displayed by Nfix(-/-) mice, namely hydrocephalus. Through the examination of embryonic and postnatal Nfix(-/-) mice we reveal that hydrocephalus is first seen at around postnatal day (P) 10 in mice lacking Nfix, and is fully penetrant by P20. Furthermore, we examined the subcommissural organ (SCO), the Sylvian aqueduct and the ependymal layer of the lateral ventricles, regions that when malformed and functionally perturbed have previously been implicated in the development of hydrocephalus. SOX3 is a factor known to regulate SCO development. Although we revealed that NFIX could repress Sox3-promoter-driven transcriptional activity in vitro, SOX3 expression within the SCO was normal within Nfix(-/-) mice, and Nfix mutant mice showed no abnormalities in the structure or function of the SCO. Moreover, these mutant mice exhibited no overt blockage of the Sylvian aqueduct. However, the ependymal layer of the lateral ventricles was frequently absent in Nfix(-/-) mice, suggesting that this phenotype may underlie the development of hydrocephalus within these knockout mice. Copyright © 2015 Elsevier B.V. All rights reserved.

T Cell Development in Mice Lacking All T Cell Receptor ζ Family Members (ζ, η, and FcεRIγ)

PubMed Central

Shores, Elizabeth W.; Ono, Masao; Kawabe, Tsutomo; Sommers, Connie L.; Tran, Tom; Lui, Kin; Udey, Mark C.; Ravetch, Jeffrey; Love, Paul E.

1998-01-01

The ζ family includes ζ, η, and FcεRIγ (Fcγ). Dimers of the ζ family proteins function as signal transducing subunits of the T cell antigen receptor (TCR), the pre-TCR, and a subset of Fc receptors. In mice lacking ζ/η chains, T cell development is impaired, yet low numbers of CD4+ and CD8+ T cells develop. This finding suggests either that pre-TCR and TCR complexes lacking a ζ family dimer can promote T cell maturation, or that in the absence of ζ/η, Fcγ serves as a subunit in TCR complexes. To elucidate the role of ζ family dimers in T cell development, we generated mice lacking expression of all of these proteins and compared their phenotype to mice lacking only ζ/η or Fcγ. The data reveal that surface complexes that are expressed in the absence of ζ family dimers are capable of transducing signals required for α/β–T cell development. Strikingly, T cells generated in both ζ/η−/− and ζ/η−/−–Fcγ−/− mice exhibit a memory phenotype and elaborate interferon γ. Finally, examination of different T cell populations reveals that ζ/η and Fcγ have distinct expression patterns that correlate with their thymus dependency. A possible function for the differential expression of ζ family proteins may be to impart distinctive signaling properties to TCR complexes expressed on specific T cell populations. PMID:9529325

Calcium-dependent protein kinase CPK28 targets the methionine adenosyltransferases for degradation by the 26S proteasome and affects ethylene biosynthesis and lignin deposition in Arabidopsis.

PubMed

Jin, Yu; Ye, Nenghui; Zhu, Fuyuan; Li, Haoxuan; Wang, Juan; Jiang, Liwen; Zhang, Jianhua

2017-04-01

S-adenosylmethionine (AdoMet) is synthesized by methionine adenosyltransferase (MAT), and plays an essential role in ethylene biosynthesis and other methylation reactions. Despite increasing knowledge of MAT regulation at transcriptional levels, how MAT is post-translationally regulated remains unknown in plant cells. Phosphorylation is an important post-translational modification for regulating the activity of enzymes, protein function and signaling transduction. Using molecular and biochemical approaches, we have identified the phosphorylation of MAT proteins by calcium-dependent protein kinase (CPK28). Phenotypically, both MAT2-overexpressing transgenic plants and cpk28 mutants display short hypocotyls and ectopic lignifications. Their shortened hypocotyl phenotypes are caused by ethylene overproduction and rescued by ethylene biosynthesis inhibitor aminoethoxyvinylglycine treatment. Genetic evidence reveals that MAT2 mutation restores the phenotype of ectopic lignification in CPK28-deficient plants. We find that total MAT proteins and AdoMet are increased in cpk28 mutants, but decreased in CPK28-overexpressing seedlings. We also find that MATs in OE::CPK28 are degraded through the 26S proteasome pathway. Our work suggests that CPK28 targets MATs (MAT1, MAT2 and MAT3) for degradation by the 26S proteasome pathway, and thus affects ethylene biosynthesis and lignin deposition in Arabidopsis. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Biogeochemical cycles of carbon, sulfur, and free oxygen in a microbial mat

NASA Technical Reports Server (NTRS)

Canfield, Donald E.; Des Marais, David J.

1993-01-01

Complete budgets for carbon and oxygen have been constructed for cyanobacterial mats dominated by Microcoleus chthonoplastes from the evaporating ponds of a salt works. We infer from the data the various sinks for O2 as well as the sources of carbon for primary production. Although seasonal variability exists, a major percentage of the O2 produced during the day did not diffuse out of the mat but was used within the mat to oxidize both organic carbon and the sulfide produced by sulfate reduction. At night, most of the O2 that diffused into the mat was used to oxidize sulfide, with O2 respiration of minor importance. During the day, the internal mat processes of sulfate reduction and O2 respiration generated as much or more inorganic carbon (DIC) for primary production as diffusion into the mat. Oxygenic photosynthesis was the most important process of carbon fixation. At night, the DIC lost from the mat was mostly from sulfate reduction. Elemental fluxes across the mat/brine interface indicated that carbon with an oxidation state of greater than zero was taken up by the mat during the day and liberated from the mat at night. Overall, carbon with an average oxidation state of near zero accumulated in the mat. Both carbon fixation and carbon oxidation rates varied with temperature by a similar amount.

75 FR 55360 - In the Matter of Mattingly Testing Services, Inc. Molt, MT; Order Revoking License (Effective...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-10

... radiation safety officer, and due to expire on February 28, 2016. The license authorizes Mattingly to... effectiveness of Mattingly's radiation safety and compliance programs by commencing an assessment of Mattingly's radiation safety program within 30 days of NRC's approval of the consultant; by reviewing Mattingly's...

Community structure of free-floating filamentous cyanobacterial mats from the Wonder Lake geothermal springs in the Philippines.

PubMed

Lacap, Donnabella C; Smith, Gavin J D; Warren-Rhodes, Kimberley; Pointing, Stephen B

2005-07-01

Cyanobacterial mats were characterized from pools of 45-60 degrees C in near-neutral pH, low-sulphide geothermal springs in the Philippines. Mat structure did not vary with temperature. All mats possessed highly ordered layers of airspaces at both the macroscopic and microscopic level, and these appear to be an adaptation to a free-floating growth habit. Upper mat layers supported biomass with elevated carotenoid:chlorophyll a ratios and an as yet uncharacterized waxy layer on the dorsal surface. Microscopic examination revealed mats comprised a single Fischerella morphotype, with abundant heterocysts throughout mats at all temperatures. Molecular analysis of mat community structure only partly matched morphological identification. All samples supported greater 16S rDNA-defined diversity than morphology suggested, with a progressive loss in the number of genotypes with increasing temperature. Fischerella-like sequences were recovered from mats occurring at all temperatures, but some mats also yielded Oscillatoria-like sequences, although corresponding phenotypes were not observed. Phylogenetic analysis revealed that Fischerella-like sequences were most closely affiliated with Fischerella major and the Oscillatoria-like sequences with Oscillatoria amphigranulata.

Histone Deacetylases 5 and 9 Govern Responsiveness of the Heart to a Subset of Stress Signals and Play Redundant Roles in Heart Development

PubMed Central

Chang, Shurong; McKinsey, Timothy A.; Zhang, Chun Li; Richardson, James A.; Hill, Joseph A.; Olson, Eric N.

2004-01-01

The adult heart responds to stress signals by hypertrophic growth, which is often accompanied by activation of a fetal cardiac gene program and eventual cardiac demise. We showed previously that histone deacetylase 9 (HDAC9) acts as a suppressor of cardiac hypertrophy and that mice lacking HDAC9 are sensitized to cardiac stress signals. Here we report that mice lacking HDAC5 display a similar cardiac phenotype and develop profoundly enlarged hearts in response to pressure overload resulting from aortic constriction or constitutive cardiac activation of calcineurin, a transducer of cardiac stress signals. In contrast, mice lacking either HDAC5 or HDAC9 show a hypertrophic response to chronic β-adrenergic stimulation identical to that of wild-type littermates, suggesting that these HDACs modulate a specific subset of cardiac stress response pathways. We also show that compound mutant mice lacking both HDAC5 and HDAC9 show a propensity for lethal ventricular septal defects and thin-walled myocardium. These findings reveal central roles for HDACs 5 and 9 in the suppression of a subset of cardiac stress signals as well as redundant functions in the control of cardiac development. PMID:15367668

Histone deacetylases 5 and 9 govern responsiveness of the heart to a subset of stress signals and play redundant roles in heart development.

PubMed

Chang, Shurong; McKinsey, Timothy A; Zhang, Chun Li; Richardson, James A; Hill, Joseph A; Olson, Eric N

2004-10-01

The adult heart responds to stress signals by hypertrophic growth, which is often accompanied by activation of a fetal cardiac gene program and eventual cardiac demise. We showed previously that histone deacetylase 9 (HDAC9) acts as a suppressor of cardiac hypertrophy and that mice lacking HDAC9 are sensitized to cardiac stress signals. Here we report that mice lacking HDAC5 display a similar cardiac phenotype and develop profoundly enlarged hearts in response to pressure overload resulting from aortic constriction or constitutive cardiac activation of calcineurin, a transducer of cardiac stress signals. In contrast, mice lacking either HDAC5 or HDAC9 show a hypertrophic response to chronic beta-adrenergic stimulation identical to that of wild-type littermates, suggesting that these HDACs modulate a specific subset of cardiac stress response pathways. We also show that compound mutant mice lacking both HDAC5 and HDAC9 show a propensity for lethal ventricular septal defects and thin-walled myocardium. These findings reveal central roles for HDACs 5 and 9 in the suppression of a subset of cardiac stress signals as well as redundant functions in the control of cardiac development.

Mice that lack the C-terminal region of Reelin exhibit behavioral abnormalities related to neuropsychiatric disorders

PubMed Central

Sakai, Kaori; Shoji, Hirotaka; Kohno, Takao; Miyakawa, Tsuyoshi; Hattori, Mitsuharu

2016-01-01

The secreted glycoprotein Reelin is believed to play critical roles in the pathogenesis of several neuropsychiatric disorders. The highly basic C-terminal region (CTR) of Reelin is necessary for efficient activation of its downstream signaling, and the brain structure of knock-in mice that lack the CTR (ΔC-KI mice) is impaired. Here, we performed a comprehensive behavioral test battery on ΔC-KI mice, in order to evaluate the effects of partial loss-of-function of Reelin on brain functions. The ΔC-KI mice were hyperactive and exhibited reduced anxiety-like and social behaviors. The working memory in ΔC-KI mice was impaired in a T-maze test. There was little difference in spatial reference memory, depression-like behavior, prepulse inhibition, or fear memory between ΔC-KI and wild-type mice. These results suggest that CTR-dependent Reelin functions are required for some specific normal brain functions and that ΔC-KI mice recapitulate some aspects of neuropsychiatric disorders, such as schizophrenia, bipolar disorder, and autism spectrum disorder. PMID:27346785

Nicotine anxiogenic and rewarding effects are decreased in mice lacking beta-endorphin.

PubMed

Trigo, José M; Zimmer, Andreas; Maldonado, Rafael

2009-06-01

The endogenous opioid system plays an important role in the behavioral effects of nicotine. Thus, micro-opioid receptor and the endogenous opioids derived from proenkephalin are involved in the central effects of nicotine. However, the role played by the different endogenous opioid peptides in the acute and chronic effects of nicotine remains to be fully established. Mice lacking beta-endorphin were acutely injected with nicotine at different doses to evaluate locomotor, anxiogenic and antinociceptive responses. The rewarding properties of nicotine were evaluated by using the conditioned place-preference paradigm. Mice chronically treated with nicotine were acutely injected with mecamylamine to study the behavioral expression of nicotine withdrawal. Mice lacking beta-endorphin exhibited a spontaneous hypoalgesia and hyperlocomotion and a reduction on the anxiogenic and rewarding effects induced by nicotine. Nicotine induced similar antinociception and hypolocomotion in both genotypes and no differences were found in the development of physical dependence. The dissociation between nicotine rewarding properties and physical dependence suggests a differential implication of beta-endorphin in these addictive related responses.

Dietary restriction ameliorates haematopoietic ageing independent of telomerase, whilst lack of telomerase and short telomeres exacerbates the ageing phenotype.

PubMed

Al-Ajmi, Nouf; Saretzki, Gabriele; Miles, Colin; Spyridopoulos, Ioakim

2014-10-01

Ageing is associated with an overall decline in the functional capacity of tissues and stem cells, including haematopoietic stem and progenitor cells (HSPCs), as well as telomere dysfunction. Dietary restriction (DR) is a recognised anti-ageing intervention that extends lifespan and improves health in several organisms. To investigate the role of telomeres and telomerase in haematopoietic ageing, we compared the HSPC profile and clonogenic capacity of bone marrow cells from wild type with telomerase-deficient mice and the effect of DR on these parameters. Compared with young mice, aged wild type mice demonstrated a significant accumulation of HSPCs (1.3% vs 0.2%, P=0.002) and elevated numbers of granulocyte/macrophage colony forming units (CFU-GM, 26.4 vs 17.3, P=0.0037) consistent with myeloid "skewing" of haematopoiesis. DR was able to restrict the increase in HSPC number as well as the myeloid "skewing" in aged wild type mice. In order to analyse the influence of short telomeres on the ageing phenotype we examined mice lacking the RNA template for telomerase, TERC(-/-). Telomere shortening resulted in a similar bone marrow phenotype to that seen in aged mice, with significantly increased HSPC numbers and an increased formation of all myeloid colony types but at a younger age than wild type mice. However, an additional increase in erythroid colonies (BFU-E) was also evident. Mice lacking telomerase reverse transcriptase without shortened telomeres, TERT(-/-), also presented with augmented haematopoietic ageing which was ameliorated by DR, demonstrating that the effect of DR was not dependent on the presence of telomerase in HSPCs. We conclude that whilst shortened telomeres mimic some aspects of haematopoietic ageing, both shortened telomeres and the lack of telomerase produce specific phenotypes, some of which can be prevented by dietary restriction. Copyright © 2014 Elsevier Inc. All rights reserved.

Mice completely lacking immunoproteasomes display major alterations in antigen presentation

PubMed Central

Kincaid, Eleanor Z; Che, Jenny W; York, Ian; Escobar, Hernando; Reyes-Vargas, Eduardo; Delgado, Julio C.; Welsh, Raymond M; Karow, Margaret L.; Murphy, Andrew J.; Valenzuela, David M.; Yancopoulos, George D.; Rock, Kenneth L

2011-01-01

The importance of immunoproteasomes to antigen presentation has been unclear because animals totally lacking immunoproteasomes have not been previously developed. Here we show that dendritic cells from mice lacking the three immunoproteasome catalytic subunits display defects in presenting multiple major histocompatability (MHC) class I epitopes. During viral infection in vivo, the presentation of a majority of MHC class I epitopes is markedly reduced in immunoproteasome-deficient animals, while presentation of MHC class II peptides is unaffected. By mass spectrometry the repertoire of MHC class I-presented peptides is ~50% different and these differences are sufficient to stimulate robust transplant rejection of wild type cells in mutant mice. These results indicate that immunoproteasomes play a much more important role in antigen presentation than previously thought. PMID:22197977

Absence of opioid stress-induced analgesia in mice lacking beta-endorphin by site-directed mutagenesis.

PubMed

Rubinstein, M; Mogil, J S; Japón, M; Chan, E C; Allen, R G; Low, M J

1996-04-30

A physiological role for beta-endorphin in endogenous pain inhibition was investigated by targeted mutagenesis of the proopiomelanocortin gene in mouse embryonic stem cells. The tyrosine codon at position 179 of the proopiomelanocortin gene was converted to a premature translational stop codon. The resulting transgenic mice display no overt developmental or behavioral alterations and have a normally functioning hypothalamic-pituitary-adrenal axis. Homozygous transgenic mice with a selective deficiency of beta-endorphin exhibit normal analgesia in response to morphine, indicating the presence of functional mu-opiate receptors. However, these mice lack the opioid (naloxone reversible) analgesia induced by mild swim stress. Mutant mice also display significantly greater nonopioid analgesia in response to cold water swim stress compared with controls and display paradoxical naloxone-induced analgesia. These changes may reflect compensatory upregulation of alternative pain inhibitory mechanisms.

The preproghrelin gene is required for the normal integration of thermoregulation and sleep in mice

PubMed Central

Szentirmai, Éva; Kapás, Levente; Sun, Yuxiang; Smith, Roy G.; Krueger, James M.

2009-01-01

Peptidergic mechanisms controlling feeding, metabolism, thermoregulation, and sleep overlap in the hypothalamus. Low ambient temperatures and food restriction induce hypothermic (torpor) bouts and characteristic metabolic and sleep changes in mice. We report that mice lacking the preproghrelin gene, but not those lacking the ghrelin receptor, have impaired abilities to manifest and integrate normal sleep and thermoregulatory responses to metabolic challenges. In response to fasting at 17 °C (a subthermoneutral ambient temperature), preproghrelin knockout mice enter hypothermic bouts associated with reduced sleep, culminating in a marked drop in body temperature to near-ambient levels. Prior treatment with obestatin, another preproghrelin gene product, attenuates the hypothermic response of preproghrelin knockout mice. Results suggest that obestatin is a component in the coordinated regulation of metabolism and sleep during torpor. PMID:19666521

MAT2B promotes adipogenesis by modulating SAMe levels and activating AKT/ERK pathway during porcine intramuscular preadipocyte differentiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Cunzhen; Chen, Xiaochang; Wu, Wenjing

Intramuscular fat (IMF) has been demonstrated as one of the crucial factors of livestock meat quality. The MAT2B protein with MAT2α catalyzes the formation of methyl donor S- adenosylmethionine (SAMe) to mediate cell metabolism including proliferation and apoptosis. However, the regulatory effect of MAT2B on IMF deposition is still unclear. In this study, the effect of MAT2B on adipogenesis and its potential mechanism during porcine intramuscular preadipocyte differentiation was studied. The results showed that overexpression of MAT2B promoted adipogenesis and significantly up-regulated the mRNA and protein levels of adipogenic marker genes including FASN, PPARγ and aP2, consistently, knockdown of MAT2Bmore » inhibited lipid accumulation and down-regulated the mRNA and protein levels of the above genes. Furthermore, flow cytometry and EdU-labeling assay indicated that MAT2B regulate adipogenesis was partly due to influence intracellular SAMe levels and further affect cell clonal expansion. Also, increased expression of MAT2B activated the phosphorylations of AKT and ERK1/2, whereas knockdown of MAT2B blocked AKT signaling and repressed the phosphorylation of ERK1/2. Moreover, the inhibitory effect of LY294002 (a specific PI3K inhibitor) on the activities of AKT and ERK1/2 was partially recovered by overexpression of MAT2B in porcine intramuscular adipocytes. Finally, Co-IP experiments showed that MAT2B can directly interact with AKT. Taken together, our findings suggested that MAT2B acted as a positive regulator through modifying SAMe levels as well as activating AKT/ERK signaling pathway to promote porcine intramuscular adipocyte differentiation. - Highlights: • MAT2B up-regulates the expression of adipogenic marker genes and promotes porcine intramuscular preadipocyte differentiation. • MAT2B influences intracellular SAMe levels and further affects cell clonal expansion. • MAT2B interacts with AKT and activates AKT/ERK signaling pathway.« less

Enhanced antibacterial nanocomposite mats by coaxial electrospinning of polycaprolactone fibers loaded with Zn-based nanoparticles.

PubMed

Prado-Prone, Gina; Silva-Bermudez, Phaedra; Almaguer-Flores, Argelia; García-Macedo, Jorge A; García, Victor I; Rodil, Sandra E; Ibarra, Clemente; Velasquillo, Cristina

2018-04-16

ZnO and Zn acetate nanoparticles were embedded in polycaprolactone coaxial-fibers and uniaxial-fibers matrices to develop potential antibacterial nanocomposite wound dressings (mats). Morphology, composition, wettability, crystallinity and fiber structure of mats were characterized. Antibacterial properties of mats were tested against E. coli and S. aureus by turbidity and MTT assays. The effect of UVA illumination (prior to bacteria inoculation) on mats' antibacterial activity was also studied. Results showed that a coaxial-fibers design maintained nanoparticles distributed in the outer-shell of fibers and, in general, enhanced the antibacterial effect of the mats, in comparison to conventional uniaxial-fibers mats. Results indicated that mats simultaneously inhibited planktonic and biofilm bacterial growth by, probably, two main antibacterial mechanisms; 1) release of Zn 2+ ions (mainly from Zn acetate nanoparticles) and 2) photocatalytic oxidative processes exerted by ZnO nanoparticles. Antibacterial properties of mats were significantly improved by coaxial-fibers design and exposure to UVA-light prior to bacteria inoculation. Copyright © 2018 Elsevier Inc. All rights reserved.

University of California San Francisco (UCSF-2): Gene Expression Profiling of Normal Mouse Skin, Hras WT and Hras -/- | Office of Cancer Genomics

Cancer.gov

This data set contains the transcriptional profiles of 20 dorsal skin samples from eight-week-old mice. Mice were generated by crossing FVB/N to Mus spretus mice to generate F1 mice, and then crossing F1 mice back to the FVB/N strain. 10  FVB/N mice lacking Hras1 (aka HrasKO, Hras-/-) and 10  FVB/N mice with wild-type Hras1 were generated. Read the abstract.

Sociability and synapse subtype-specific defects in mice lacking SRPX2, a language-associated gene

PubMed Central

Cong, Qifei; Palmer, Christian R.

2018-01-01

The FoxP2 transcription factor and its target genes have been implicated in developmental brain diseases with a prominent language component, such as developmental verbal dyspraxia and specific language impairment. How FoxP2 affects neural circuitry development remains poorly understood. The sushi domain protein SRPX2 is a target of FoxP2, and mutations in SRPX2 are associated with language defects in humans. We have previously shown that SRPX2 is a synaptogenic protein that increases excitatory synapse density. Here we provide the first characterization of mice lacking the SRPX2 gene, and show that these mice exhibit defects in both neural circuitry and communication and social behaviors. Specifically, we show that mice lacking SRPX2 show a specific reduction in excitatory VGlut2 synapses in the cerebral cortex, while VGlut1 and inhibitory synapses were largely unaffected. SRPX2 KO mice also exhibit an abnormal ultrasonic vocalization ontogenetic profile in neonatal pups, and reduced preference for social novelty. These data demonstrate a functional role for SRPX2 during brain development, and further implicate FoxP2 and its targets in regulating the development of vocalization and social circuits. PMID:29920554

Osteocyte-derived RANKL is a critical mediator of the increased bone resorption caused by dietary calcium deficiency

PubMed Central

Xiong, Jinhu; Piemontese, Marilina; Thostenson, Jeff D.; Weinstein, Robert S.; Manolagas, Stavros C.; O’Brien, Charles A.

2014-01-01

Parathyroid hormone (PTH) excess stimulates bone resorption. This effect is associated with increased expression of the osteoclastogenic cytokine receptor activator of nuclear factor кB ligand (RANKL) in bone. However, several different cell types, including bone marrow stromal cells, osteocytes, and T lymphocytes, express both RANKL and the PTH receptor and it is unclear whether RANKL expression by any of these cell types is required for PTH-induced bone loss. Here we have used mice lacking the RANKL gene in osteocytes to determine whether RANKL produced by this cell type is required for the bone loss caused by secondary hyperparathyroidism induced by dietary calcium deficiency in adult mice. Thirty days of dietary calcium deficiency caused bone loss in control mice, but this effect was blunted in mice lacking RANKL in osteocytes. The increase in RANKL expression in bone and the increase in osteoclast number caused by dietary calcium deficiency were also blunted in mice lacking RANKL in osteocytes. These results demonstrate that RANKL produced by osteocytes contributes to the increased bone resorption and the bone loss caused by secondary hyperparathyroidism, strengthening the evidence that osteocytes are an important target cell for hormonal control of bone remodeling. PMID:24933342

Studying Microbial Mat Functioning Amidst "Unexpected Diversity": Methodological Approaches and Initial Results from Metatranscriptomes of Mats Over Diel cycles, iTags from Long Term Manipulations, and Biogeochemical Cycling in Simplified Microbial Mats Constructed from Cultures

NASA Astrophysics Data System (ADS)

Bebout, B.; Bebout, L. E.; Detweiler, A. M.; Everroad, R. C.; Lee, J.; Pett-Ridge, J.; Weber, P. K.

2014-12-01

Microbial mats are famously amongst the most diverse microbial ecosystems on Earth, inhabiting some of the most inclement environments known, including hypersaline, dry, hot, cold, nutrient poor, and high UV environments. The high microbial diversity of microbial mats makes studies of microbial ecology notably difficult. To address this challenge, we have been using a combination of metagenomics, metatranscriptomics, iTags and culture-based simplified microbial mats to study biogeochemical cycling (H2 production, N2 fixation, and fermentation) in microbial mats collected from Elkhorn Slough, Monterey Bay, California. Metatranscriptomes of microbial mats incubated over a diel cycle have revealed that a number of gene systems activate only during the day in Cyanobacteria, while the remaining appear to be constitutive. The dominant cyanobacterium in the mat (Microcoleus chthonoplastes) expresses several pathways for nitrogen scavenging undocumented in cultured strains, as well as the expression of two starch storage and utilization cycles. Community composition shifts in response to long term manipulations of mats were assessed using iTags. Changes in community diversity were observed as hydrogen fluxes increased in response to a lowering of sulfate concentrations. To produce simplified microbial mats, we have isolated members of 13 of the 15 top taxa from our iTag libraries into culture. Simplified microbial mats and simple co-cultures and consortia constructed from these isolates reproduce many of the natural patterns of biogeochemical cycling in the parent natural microbial mats, but against a background of far lower overall diversity, simplifying studies of changes in gene expression (over the short term), interactions between community members, and community composition changes (over the longer term), in response to environmental forcing.

Accuracy of a vertical jump contact mat for determining jump height and flight time.

PubMed

Whitmer, Tyler D; Fry, Andrew C; Forsythe, Charles M; Andre, Matthew J; Lane, Michael T; Hudy, Andrea; Honnold, Darric E

2015-04-01

Several devices are available to measure vertical jump (VJ) height based on flight time, VJ reach height, or ground reaction forces. The purpose of this study was to determine the accuracy of a VJ mat for measuring flight time and VJ height compared with a VJ tester or a force plate. Seventeen men and 18 women (X ± SD; age = 20.9 ± 0.7 years, height = 176.1 ± 0.9 cm, weight = 72.6 ± 13.5 kg) served as subjects. Subjects performed counter-movement vertical jumps while standing on both a force plate (1,000 Hz) and a VJ mat. A Vertec VJ tester was used to measure jump reach. Compared with the force plate, the VJ mat reported greater VJ height (VJ mat = 0.50 ± 0.12 m, force plate = 0.34 ± 0.10 m) and flight time (VJ mat = 0.629 ± 0.078 seconds, force plate = 0.524 ± 0.077 seconds). Comparison of VJ heights from the VJ mat and the Vertec revealed no significant differences (Vertec = 0.48 ± 0.11 m). Regression analyses indicated strong relationships between testing methods and suggested that high VJ performances may be underestimated with the VJ mat. This particular VJ mat compared favorably with the Vertec but not the force plate. It seems that the different flight times derived from the VJ mat may permit the VJ mat to be in closer agreement with VJ heights from the Vertec. Also, the VJ mat may not be an appropriate tool for assessing high VJ performances (i.e., ≥0.70 m; ≈28 inches). Practitioners and researchers using similar VJ mats may not obtain accurate flight times and may underestimate high performers.

Ecological genomics of the newly discovered diazotrophic filamentous cyanobacterium ESFC-1

NASA Astrophysics Data System (ADS)

Everroad, C.; Bebout, B.; Bebout, L. E.; Detweiler, A. M.; Lee, J.; Mayali, X.; Singer, S. W.; Stuart, R.; Weber, P. K.; Woebken, D.; Pett-Ridge, J.

2014-12-01

Cyanobacteria-dominated microbial mats played a key role in the evolution of the early Earth and provide a model for exploring the relationships between ecology, evolution and biogeochemistry. A recently described nonheterocystous filamentous cyanobacterium, strain ESFC-1, has been shown to be a major diazotroph year round in the intertidal microbial mat system at Elkhorn Slough, CA, USA. Based on phylogenetic analyses of the 16s RNA gene, ESFC-1 appears to belong to a unique, genus-level divergence within the cyanobacteria. Consequently, the draft genome sequence of this strain has been determined. Here we report features of this genome, particularly as they relate to the ecological functions and capabilities of strain ESFC-1. One striking feature of this cyanobacterium is the apparent lack of a functional bi-directional hydrogenase typically expected to be found within a diazotroph; consortia- and culture-based experiments exploring the metabolic processes of ESFC-1 also indicate that this hydrogenase is absent. Co-culture studies with ESFC-1 and some of the dominant heterotrophic members within the microbial mat system, including the ubiquitous Flavobacterium Muricauda sp., which often is found associated with cyanobacteria in nature and in culture collections worldwide, have also been performed. We report on these species-species interactions, including materials exchange between the cyanobacterium and heterotrophic bacterium. The combination of genomics with culture- and consortia-based experimental research is a powerful tool for understanding microbial processes and interactions in complex ecosystems.

The role of CD27-CD70-mediated T cell co-stimulation in vasculogenesis, arteriogenesis and angiogenesis.

PubMed

Simons, K H; Aref, Z; Peters, H A B; Welten, S P; Nossent, A Y; Jukema, J W; Hamming, J F; Arens, R; de Vries, M R; Quax, P H A

2018-06-01

T cells have a distinctive role in neovascularization, which consists of arteriogenesis and angiogenesis under pathological conditions and vasculogenesis under physiological conditions. However, the role of co-stimulation in T cell activation in neovascularization has yet to be established. The aim of this study was to investigate the role T cell co-stimulation and inhibition in angiogenesis, arteriogenesis and vasculogenesis. Hind limb ischemia was induced by double ligation of the left femoral artery in mice and blood flow recovery was measured with Laser Doppler Perfusion Imaging in control, CD70 -/- , CD80/86 -/- , CD70/80/86 -/- and CTLA4 +/- mice. Blood flow recovery was significantly impaired in mice lacking CD70 compared to control mice, but was similar in CD80/86 -/- , CTLA4 +/- and control mice. Mice lacking CD70 showed impaired vasculogenesis, since the number of pre-existing collaterals was reduced as observed in the pia mater compared to control mice. In vitro an impaired capability of vascular smooth muscle cells (VSMC) to activate T cells was observed in VSMC lacking CD70. Furthermore, CD70 -/- , CD80/86 -/- and CD70/80/86 -/- mice showed reduced angiogenesis in the soleus muscle 10 days after ligation. Arteriogenesis was also decreased in CD70 -/- compared to control mice 10 and 28 days after surgery. The present study is the first to describe an important role for T cell activation via co-stimulation in angiogenesis, arteriogenesis and vasculogenesis, where the CD27-CD70 T cell co-stimulation pathway appears to be the most important co-stimulation pathway in pre-existing collateral formation and post-ischemic blood flow recovery, by arteriogenesis and angiogenesis. Copyright © 2018 Elsevier B.V. All rights reserved.

Albumin contributes to kidney disease progression in Alport syndrome

PubMed Central

Knutsen, Russell H.; Mecham, Robert P.

2016-01-01

Alport syndrome is a familial kidney disease caused by defects in the collagen type IV network of the glomerular basement membrane. Lack of collagen-α3α4α5(IV) changes the glomerular basement membrane morphologically and functionally, rendering it leaky to albumin and other plasma proteins. Filtered albumin has been suggested to be a cause of the glomerular and tubular injuries observed at advanced stages of Alport syndrome. To directly investigate the role that albumin plays in the progression of disease in Alport syndrome, we generated albumin knockout (Alb−/−) mice to use as a tool for removing albuminuria as a component of kidney disease. Mice lacking albumin were healthy and indistinguishable from control littermates, although they developed hypertriglyceridemia. Dyslipidemia was observed in Alb+/− mice, which displayed half the normal plasma albumin concentration. Alb mutant mice were bred to collagen-α3(IV) knockout (Col4a3−/−) mice, which are a model for human Alport syndrome. Lack of circulating and filtered albumin in Col4a3−/−;Alb−/− mice resulted in dramatically improved kidney disease outcomes, as these mice lived 64% longer than did Col4a3−/−;Alb+/+ and Col4a3−/−;Alb+/− mice, despite similar blood pressures and serum triglyceride levels. Further investigations showed that the absence of albumin correlated with reduced transforming growth factor-β1 signaling as well as reduced tubulointerstitial, glomerular, and podocyte pathology. We conclude that filtered albumin is injurious to kidney cells in Alport syndrome and perhaps in other proteinuric kidney diseases, including diabetic nephropathy. PMID:27147675

Albumin contributes to kidney disease progression in Alport syndrome.

PubMed

Jarad, George; Knutsen, Russell H; Mecham, Robert P; Miner, Jeffrey H

2016-07-01

Alport syndrome is a familial kidney disease caused by defects in the collagen type IV network of the glomerular basement membrane. Lack of collagen-α3α4α5(IV) changes the glomerular basement membrane morphologically and functionally, rendering it leaky to albumin and other plasma proteins. Filtered albumin has been suggested to be a cause of the glomerular and tubular injuries observed at advanced stages of Alport syndrome. To directly investigate the role that albumin plays in the progression of disease in Alport syndrome, we generated albumin knockout (Alb(-/-)) mice to use as a tool for removing albuminuria as a component of kidney disease. Mice lacking albumin were healthy and indistinguishable from control littermates, although they developed hypertriglyceridemia. Dyslipidemia was observed in Alb(+/-) mice, which displayed half the normal plasma albumin concentration. Alb mutant mice were bred to collagen-α3(IV) knockout (Col4a3(-/-)) mice, which are a model for human Alport syndrome. Lack of circulating and filtered albumin in Col4a3(-/-);Alb(-/-) mice resulted in dramatically improved kidney disease outcomes, as these mice lived 64% longer than did Col4a3(-/-);Alb(+/+) and Col4a3(-/-);Alb(+/-) mice, despite similar blood pressures and serum triglyceride levels. Further investigations showed that the absence of albumin correlated with reduced transforming growth factor-β1 signaling as well as reduced tubulointerstitial, glomerular, and podocyte pathology. We conclude that filtered albumin is injurious to kidney cells in Alport syndrome and perhaps in other proteinuric kidney diseases, including diabetic nephropathy. Copyright © 2016 the American Physiological Society.

Female Mice Lacking Estrogen Receptor-α in Hypothalamic Proopiomelanocortin (POMC) Neurons Display Enhanced Estrogenic Response on Cortical Bone Mass.

PubMed

Farman, H H; Windahl, S H; Westberg, L; Isaksson, H; Egecioglu, E; Schele, E; Ryberg, H; Jansson, J O; Tuukkanen, J; Koskela, A; Xie, S K; Hahner, L; Zehr, J; Clegg, D J; Lagerquist, M K; Ohlsson, C

2016-08-01

Estrogens are important regulators of bone mass and their effects are mainly mediated via estrogen receptor (ER)α. Central ERα exerts an inhibitory role on bone mass. ERα is highly expressed in the arcuate (ARC) and the ventromedial (VMN) nuclei in the hypothalamus. To test whether ERα in proopiomelanocortin (POMC) neurons, located in ARC, is involved in the regulation of bone mass, we used mice lacking ERα expression specifically in POMC neurons (POMC-ERα(-/-)). Female POMC-ERα(-/-) and control mice were ovariectomized (OVX) and treated with vehicle or estradiol (0.5 μg/d) for 6 weeks. As expected, estradiol treatment increased the cortical bone thickness in femur, the cortical bone mechanical strength in tibia and the trabecular bone volume fraction in both femur and vertebrae in OVX control mice. Importantly, the estrogenic responses were substantially increased in OVX POMC-ERα(-/-) mice compared with the estrogenic responses in OVX control mice for cortical bone thickness (+126 ± 34%, P < .01) and mechanical strength (+193 ± 38%, P < .01). To test whether ERα in VMN is involved in the regulation of bone mass, ERα was silenced using an adeno-associated viral vector. Silencing of ERα in hypothalamic VMN resulted in unchanged bone mass. In conclusion, mice lacking ERα in POMC neurons display enhanced estrogenic response on cortical bone mass and mechanical strength. We propose that the balance between inhibitory effects of central ERα activity in hypothalamic POMC neurons in ARC and stimulatory peripheral ERα-mediated effects in bone determines cortical bone mass in female mice.

Diversity, distribution and hydrocarbon biodegradation capabilities of microbial communities in oil-contaminated cyanobacterial mats from a constructed wetland.

PubMed

Abed, Raeid M M; Al-Kharusi, Samiha; Prigent, Stephane; Headley, Tom

2014-01-01

Various types of cyanobacterial mats were predominant in a wetland, constructed for the remediation of oil-polluted residual waters from an oil field in the desert of the south-eastern Arabian Peninsula, although such mats were rarely found in other wetland systems. There is scarce information on the bacterial diversity, spatial distribution and oil-biodegradation capabilities of freshwater wetland oil-polluted mats. Microbial community analysis by Automated Ribosomal Spacer Analysis (ARISA) showed that the different mats hosted distinct microbial communities. Average numbers of operational taxonomic units (OTUsARISA) were relatively lower in the mats with higher oil levels and the number of shared OTUsARISA between the mats was <60% in most cases. Multivariate analyses of fingerprinting profiles indicated that the bacterial communities in the wetland mats were influenced by oil and ammonia levels, but to a lesser extent by plant density. In addition to oil and ammonia, redundancy analysis (RDA) showed also a significant contribution of temperature, dissolved oxygen and sulfate concentration to the variations of the mats' microbial communities. Pyrosequencing yielded 282,706 reads with >90% of the sequences affiliated to Proteobacteria (41% of total sequences), Cyanobacteria (31%), Bacteriodetes (11.5%), Planctomycetes (7%) and Chloroflexi (3%). Known autotrophic (e.g. Rivularia) and heterotrophic (e.g. Azospira) nitrogen-fixing bacteria as well as purple sulfur and non-sulfur bacteria were frequently encountered in all mats. On the other hand, sequences of known sulfate-reducing bacteria (SRBs) were rarely found, indicating that SRBs in the wetland mats probably belong to yet-undescribed novel species. The wetland mats were able to degrade 53-100% of C12-C30 alkanes after 6 weeks of incubation under aerobic conditions. We conclude that oil and ammonia concentrations are the major key players in determining the spatial distribution of the wetland mats' microbial communities and that these mats contribute directly to the removal of hydrocarbons from oil field wastewaters.

Evidence for Sexual Reproduction: Identification, Frequency, and Spatial Distribution of Venturia effusa (Pecan Scab) Mating Type Idiomorphs.

PubMed

Young, Carolyn A; Bock, Clive H; Charlton, Nikki D; Mattupalli, Chakradhar; Krom, Nick; Bowen, Joanna K; Templeton, Matthew; Plummer, Kim M; Wood, Bruce W

2018-05-10

Venturia effusa (syn. Fusicladium effusum), causal agent of pecan scab, is the most prevalent pathogen of pecan (Carya illinoinensis), causing severe yield losses in the southeastern United States. V. effusa is currently known only by its asexual (conidial) stage. However, the degree and distribution of genetic diversity observed within and among populations of V. effusa are typical of a sexually reproducing fungal pathogen, and comparable with other dothideomycetes with a known sexual stage, including the closely related apple scab pathogen, V. inaequalis. Using the mating type (MAT) idiomorphs from V. inaequalis, we identified a single MAT gene, MAT1-1-1, in a draft genome of V. effusa. The MAT1-1-1 locus is flanked by two conserved genes encoding a DNA lyase (APN2) and a hypothetical protein. The MAT locus spanning the flanking genes was amplified and sequenced from a subset of 14 isolates, of which 7 contained MAT1-1-1 and the remaining samples contained MAT1-2-1. A multiplex polymerase chain reaction screen was developed to amplify MAT1-1-1, MAT1-2-1, and a conserved reference gene encoding β-tubulin, and used to screen 784 monoconidial isolates of V. effusa collected from 11 populations of pecan across the southeastern United States. A hierarchical sampling protocol representing region, orchard, and tree allowed for analysis of MAT structure at different spatial scales. Analysis of this collection revealed the frequency of the MAT idiomorphs is in a 1:1 equilibrium of MAT1-1:MAT1-2. The apparent equilibrium of the MAT idiomorphs provides impetus for a renewed effort to search for the sexual stage of V. effusa. [Formula: see text] Copyright © 2018 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Biogeochemical cycles of carbon, sulfur, and free oxygen in a microbial mat

NASA Astrophysics Data System (ADS)

Canfield, Donald E.; Des Marais, David J.

1993-08-01

Complete budgets for carbon and oxygen have been constructed for cyanobacterial mats dominated by Microcoleus chthonoplastes from the evaporating ponds of a salt works located in Guerrero Negro, Baja California Sur, Mexico. Included in the budget are measured rates of O 2 production, sulfate reduction, and elemental exchange across the mat/brine interface, day and night, at various temperatures and times of the year. We infer from this data the various sinks for O 2, as well as the sources of carbon for primary production. To summarize, although seasonal variability exists, a major percentage of the O 2 produced during the day did not diffuse out of the mat but was used within the mat to oxidize both organic carbon and the sulfide produced by sulfate reduction. At night, most of the O 2 that diffused into the mat was used to oxidize sulfide, with O 2 respiration of minor importance. During the day, the internal mat processes of sulfate reduction and O 2 respiration generated as much or more inorganic carbon (DIC) for primary production as diffusion into the mat. Also, oxygenic photosynthesis was the most important process of carbon fixation, although anoxygenic photosynthesis may have been important at low light levels during some times of the year. At night, the DIC lost from the mat was mostly from sulfate reduction. Elemental fluxes across the mat/brine interface indicated that carbon with an oxidation state of greater than zero was taken up by the mat during the day and liberated from the mat at night. Overall, carbon with an average oxidation state of near zero accumulated in the mat. Both carbon fixation and carbon oxidation rates varied with temperature by a similar amount. These mats are thus closely coupled systems where rapid rates of photosynthesis both require and fuel rapid rates of heterotrophic carbon oxidation.

Analysis of the MAT1-1 and MAT1-2 Gene Ratio in Black Koji Molds Isolated from Meju.

PubMed

Mageswari, Anbazhagan; Kim, Jeong-Seon; Cheon, Kyu-Ho; Kwon, Soon-Wo; Yamada, Osamu; Hong, Seung-Beom

2016-12-01

Aspergillus luchuensis is known as an industrially important fungal species used for making fermented foods such as awamori and shochu in Japan, makgeolli and Meju in Korea, and Pu-erh tea in China. Nonetheless, this species has not yet been widely studied regarding mating-type genes. In this study, we examined the MAT1-1 and MAT1-2 gene ratio in black koji molds ( A. luchuensis , Aspergillus niger , and Aspergillus tubingensis ) and in Aspergillus welwitschiae isolated from Meju, a fermented soybean starting material for traditional soy sauce and soybean paste in Korea. The number of strains with the MAT1-1 locus was 2 of 23 ( A. luchuensis ), 6 of 13 ( A. tubingensis ), 21 of 28 ( A. niger ), and 5 of 10 ( A. welwitschiae ). Fungal species A. tubingensis and A. welwitschiae showed a 1 : 1 ratio of MAT1-1 and MAT1-2 mating-type loci. In contrast, A. luchuensis revealed predominance of MAT1-2 (91.3%) and A. niger of MAT1-1 (75%). We isolated and identified 2 A. luchuensis MAT1-1 strains from Meju, although all strains for making shochu in Japan are of the MAT1-2 type. These strains may be a good resource for breeding of A. luchuensis to be used in the Asian fermented-food industry.

Analysis of the MAT1-1 and MAT1-2 Gene Ratio in Black Koji Molds Isolated from Meju

PubMed Central

Mageswari, Anbazhagan; Kim, Jeong-seon; Cheon, Kyu-Ho; Kwon, Soon-Wo

2016-01-01

Aspergillus luchuensis is known as an industrially important fungal species used for making fermented foods such as awamori and shochu in Japan, makgeolli and Meju in Korea, and Pu-erh tea in China. Nonetheless, this species has not yet been widely studied regarding mating-type genes. In this study, we examined the MAT1-1 and MAT1-2 gene ratio in black koji molds (A. luchuensis, Aspergillus niger, and Aspergillus tubingensis) and in Aspergillus welwitschiae isolated from Meju, a fermented soybean starting material for traditional soy sauce and soybean paste in Korea. The number of strains with the MAT1-1 locus was 2 of 23 (A. luchuensis), 6 of 13 (A. tubingensis), 21 of 28 (A. niger), and 5 of 10 (A. welwitschiae). Fungal species A. tubingensis and A. welwitschiae showed a 1 : 1 ratio of MAT1-1 and MAT1-2 mating-type loci. In contrast, A. luchuensis revealed predominance of MAT1-2 (91.3%) and A. niger of MAT1-1 (75%). We isolated and identified 2 A. luchuensis MAT1-1 strains from Meju, although all strains for making shochu in Japan are of the MAT1-2 type. These strains may be a good resource for breeding of A. luchuensis to be used in the Asian fermented-food industry. PMID:28154484

Alignment of Irregular Grains by Mechanical Torques

NASA Astrophysics Data System (ADS)

Hoang, Thiem; Cho, Jungyeon; Lazarian, A.

2018-01-01

We study the alignment of irregular dust grains by mechanical torques due to the drift of grains through the ambient gas. We first calculate mechanical alignment torques (MATs) resulting from specular reflection of gas atoms for seven irregular shapes: one shape of mirror symmetry, three highly irregular shapes (HIS), and three weakly irregular shapes (WIS). We find that the grain with mirror symmetry experiences negligible MATs due to its mirror-symmetry geometry. Three HIS can produce strong MATs, which exhibit some generic properties as radiative torques (RATs), while three WIS produce less efficient MATs. We then study grain alignment by MATs for the different angles between the drift velocity and the ambient magnetic field, for paramagnetic and superparamagnetic grains assuming efficient internal relaxation. We find that for HIS grains, MATs can align subsonically drifting grains in the same way as RATs, with low-J and high-J attractors. For supersonic drift, MATs can align grains with low-J and high-J attractors, analogous to RAT alignment by anisotropic radiation. We also show that the joint action of MATs and magnetic torques in grains with iron inclusions can lead to perfect MAT alignment. Our results point out the potential importance of MAT alignment for HIS grains predicted by the analytical model of Lazarian & Hoang, although more theoretical and observational studies are required due to uncertainty in the shape of interstellar grains. We outline astrophysical environments where MAT alignment is potentially important.

Characterization of a genetically engineered mouse model of hemophilia A with complete deletion of the F8 gene.

PubMed

Chao, B N; Baldwin, W H; Healey, J F; Parker, E T; Shafer-Weaver, K; Cox, C; Jiang, P; Kanellopoulou, C; Lollar, P; Meeks, S L; Lenardo, M J

2016-02-01

ESSENTIALS: Anti-factor VIII (FVIII) inhibitory antibody formation is a severe complication in hemophilia A therapy. We genetically engineered and characterized a mouse model with complete deletion of the F8 coding region. F8(TKO) mice exhibit severe hemophilia, express no detectable F8 mRNA, and produce FVIII inhibitors. The defined background and lack of FVIII in F8(TKO) mice will aid in studying FVIII inhibitor formation. The most important complication in hemophilia A treatment is the development of inhibitory anti-Factor VIII (FVIII) antibodies in patients after FVIII therapy. Patients with severe hemophilia who express no endogenous FVIII (i.e. cross-reacting material, CRM) have the greatest incidence of inhibitor formation. However, current mouse models of severe hemophilia A produce low levels of truncated FVIII. The lack of a corresponding mouse model hampers the study of inhibitor formation in the complete absence of FVIII protein. We aimed to generate and characterize a novel mouse model of severe hemophilia A (designated the F8(TKO) strain) lacking the complete coding sequence of F8 and any FVIII CRM. Mice were created on a C57BL/6 background using Cre-Lox recombination and characterized using in vivo bleeding assays, measurement of FVIII activity by coagulation and chromogenic assays, and anti-FVIII antibody production using ELISA. All F8 exonic coding regions were deleted from the genome and no F8 mRNA was detected in F8(TKO) mice. The bleeding phenotype of F8(TKO) mice was comparable to E16 mice by measurements of factor activity and tail snip assay. Similar levels of anti-FVIII antibody titers after recombinant FVIII injections were observed between F8(TKO) and E16 mice. We describe a new C57BL/6 mouse model for severe hemophilia A patients lacking CRM. These mice can be directly bred to the many C57BL/6 strains of genetically engineered mice, which is valuable for studying the impact of a wide variety of genes on FVIII inhibitor formation on a defined genetic background. © 2015 International Society on Thrombosis and Haemostasis.

Lipophilic pigments from cyanobacterial (blue-green algal) and diatom mats in Hamelin Pool, Shark Bay, Western Australia

NASA Technical Reports Server (NTRS)

Palmisano, A. C.; Summons, R. E.; Cronin, S. E.; Des Marais, D. J.

1989-01-01

Lipophilic pigments were examined in microbial mat communities dominated by cyanobacteria in the intertidal zone and by diatoms in the subtidal and sublittoral zones of Hamelin Pool, Shark Bay, Western Australia. These microbial mats have evolutionary significance because of their similarity to lithfied stromatolites from the Proterozoic and Early Paleozoic eras. Fucoxanthin, diatoxanthin, diadinoxanthin, beta-carotene, and chlorophylls a and c characterized the diatom mats, whereas cyanobacterial mats contained myxoxanthophyll, zeaxanthin, echinenone, beta-carotene, chlorophyll a and, in some cases, sheath pigment. The presence of bacteriochlorophyll a within the mats suggest a close association of photosynthetic bacteria with diatoms and cyanobacteria. The high carotenoids : chlorophyll a ratios (0.84-2.44 wt/wt) in the diatom mats suggest that carotenoids served a photoprotective function in this high light environment. By contrast, cyanobacterial sheath pigment may have largely supplanted the photoprotective role of carotenoids in the intertidal mats.

Material Model Evaluation of a Composite Honeycomb Energy Absorber

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Annett, Martin S.; Fasanella, Edwin L.; Polanco, Michael A.

2012-01-01

A study was conducted to evaluate four different material models in predicting the dynamic crushing response of solid-element-based models of a composite honeycomb energy absorber, designated the Deployable Energy Absorber (DEA). Dynamic crush tests of three DEA components were simulated using the nonlinear, explicit transient dynamic code, LS-DYNA . In addition, a full-scale crash test of an MD-500 helicopter, retrofitted with DEA blocks, was simulated. The four material models used to represent the DEA included: *MAT_CRUSHABLE_FOAM (Mat 63), *MAT_HONEYCOMB (Mat 26), *MAT_SIMPLIFIED_RUBBER/FOAM (Mat 181), and *MAT_TRANSVERSELY_ANISOTROPIC_CRUSHABLE_FOAM (Mat 142). Test-analysis calibration metrics included simple percentage error comparisons of initial peak acceleration, sustained crush stress, and peak compaction acceleration of the DEA components. In addition, the Roadside Safety Verification and Validation Program (RSVVP) was used to assess similarities and differences between the experimental and analytical curves for the full-scale crash test.

Lignin-based active anode materials synthesized from low-cost renewable resources

DOEpatents

Rios, Orlando; Tenhaeff, Wyatt Evan; Daniel, Claus; Dudney, Nancy Johnston; Johs, Alexander; Nunnery, Grady Alexander; Baker, Frederick Stanley

2016-06-07

A method of making an anode includes the steps of providing fibers from a carbonaceous precursor, the carbon fibers having a glass transition temperature T.sub.g. In one aspect the carbonaceous precursor is lignin. The carbonaceous fibers are placed into a layered fiber mat. The fiber mat is fused by heating the fiber mat in the presence of oxygen to above the T.sub.g but no more than 20% above the T.sub.g to fuse fibers together at fiber to fiber contact points and without melting the bulk fiber mat to create a fused fiber mat through oxidative stabilization. The fused fiber mat is carbonized by heating the fused fiber mat to at least 650.degree. C. under an inert atmosphere to create a carbonized fused fiber mat. A battery anode formed from carbonaceous precursor fibers is also disclosed.

Simple Strategy to Prevent Severe Head Trauma in Judo —Biomechanical Analysis—

PubMed Central

Murayama, Haruo; Hitosugi, Masahito; Motozawa, Yasuki; Ogino, Masahiro; Koyama, Katsuhiro

2013-01-01

To determine whether the use of an under-mat has an effect on impact forces to the head in Judo, a Judo expert threw an anthropomorphic test device using the Osoto-gari and Ouchi-gari techniques onto a tatami (judo mat) with and without an under-mat. Head acceleration was measured and the head injury criterion (HIC) values with or without under-mat were compared. The use of an under-mat significantly decreased (p = 0.021) the HIC values from 1174.7 ± 246.7 (without under-mat) to 539.3 ± 43.5 in Ouchi-gari and from 330.0 ± 78.3 (without under-mat) to 156.1 ± 30.4 in Osoto-gari. The use of an under-mat simply reduces impact forces to the head in Judo. Rule changes are not necessary and the enjoyment and health benefits of Judo are maintained. PMID:24067767

Simple strategy to prevent severe head trauma in Judo.

PubMed

Murayama, Haruo; Hitosugi, Masahito; Motozawa, Yasuki; Ogino, Masahiro; Koyama, Katsuhiro

2013-01-01

To determine whether the use of an under-mat has an effect on impact forces to the head in Judo, a Judo expert threw an anthropomorphic test device using the Osoto-gari and Ouchi-gari techniques onto a tatami (judo mat) with and without an under-mat. Head acceleration was measured and the head injury criterion (HIC) values with or without under-mat were compared. The use of an under-mat significantly decreased (p = 0.021) the HIC values from 1174.7 ± 246.7 (without under-mat) to 539.3 ± 43.5 in Ouchi-gari and from 330.0 ± 78.3 (without under-mat) to 156.1 ± 30.4 in Osoto-gari. The use of an under-mat simply reduces impact forces to the head in Judo. Rule changes are not necessary and the enjoyment and health benefits of Judo are maintained.

Distribution of green algal mats throughout shallow soft bottoms of the Swedish Skagerrak archipelago in relation to nutrient sources and wave exposure

NASA Astrophysics Data System (ADS)

Pihl, Leif; Svenson, Anders; Moksnes, Per-Olav; Wennhage, Håkan

1999-06-01

Distribution and biomass of green algal mats were studied in marine shallow (0-1 m) soft-bottom areas on the Swedish west coast from 1994 to 1996, by combining aerial photography surveys with ground truth sampling. Filamentous green algae, dominated by species of the genera Cladophora and Enteromorpha, were generally present throughout the study area during July and August, and largely absent in late April and early May. These algae occurred at 60 to 90% of the locations investigated during the summer, and were estimated to cover between 30 and 50% of the total area of shallow soft bottoms of the Swedish Skagerrak archipelago. The distributional patterns were similar during the three years of the investigation and appeared unrelated to annual local nutrient inputs from point sources and river discharge. We postulate that the apparent lack of such a relationship is due to an altered state of nutrient dynamics throughout the archipelago. Mechanisms are likely to involve long-term, diffuse elevations in nutrient levels in coastal waters of the Skagerrak and the Kattegat over several decades leading to current eutrophic conditions, exceeding nutrient requirements for abundant filamentous algal growth. Patterns of algal abundance in our study were largely related to physical factors such as exposure to wind, waves and water exchange under conditions where nutrient loads among embayments seemed to be unlimited. Further, our results show that sediments covered by algal mats had higher carbon and nitrogen contents than unvegetated sediments. We hypothesise that sustained high nutrient loads, manifested in extensive biomass of filamentous algae during summer months, are re-mineralised via decay and sedimentation in the benthic realm. Hence, accumulated carbon and nutrients in the sediment could, in turn, constitute the basic pool for future algal mat production overlying soft bottoms in areas where tidal exchange is limited.

Increased bone density in mice lacking the proton receptor, OGR1

PubMed Central

Krieger, Nancy S.; Yao, Zhenqiang; Kyker-Snowman, Kelly; Kim, Min Ho; Boyce, Brendan F.; Bushinsky, David A.

2016-01-01

Chronic metabolic acidosis stimulates cell-mediated calcium efflux from bone through osteoblastic prostaglandin E2-induced stimulation of RANKL leading to increased osteoclastic bone resorption. Osteoblasts express the proton-sensing G-protein coupled receptor, OGR1, which activates IP3-mediated intracellular calcium. Proton-induced osteoblastic intracellular calcium signaling requires OGR1, suggesting OGR1 is the sensor activated during acidosis to cause bone resorption. Growing mice produce large amounts of metabolic acids which must be buffered, primarily by bone, prior to excretion by the kidney. Here we tested whether lack of OGR1 inhibits proton-induced bone resorption by measuring bone mineral density by μCT and histomorphometry in 8 week old male OGR1−/− and C57/Bl6 wild type mice. OGR1−/− mice have normal skeletal development with no atypical gross phenotype. Trabecular and cortical bone volume was increased in tibiae and vertebrae from OGR1−/−. There were increased osteoblast numbers on the cortical and trabecular surfaces of tibiae from OGR1−/− mice, increased endocortical and trabecular bone formation rates, and osteoblastic gene expression. Osteoclast numbers and surface were increased in tibiae of OGR1−/− mice. Thus, in rapidly growing mice, lack of OGR1 leads to increased bone mass with increased bone turnover and a greater increase in bone formation than resorption. This supports the important role of the proton receptor, OGR1, in the response of bone to protons. PMID:26880453

Extracellular Superoxide Dismutase Inhibits Innate Immune Responses and Clearance of an Intracellular Bacterial Infection

PubMed Central

Break, Timothy J.; Jun, Sujung; Indramohan, Mohanalaxmi; Carr, Karen D.; Sieve, Amy N.; Dory, Ladislav; Berg, Rance E.

2012-01-01

Reactive oxygen and nitrogen species (ROS/RNS) play important roles during immune responses to bacterial pathogens. Extracellular superoxide dismutase (ecSOD) regulates extracellular concentrations of ROS/RNS and contributes to tissue protection during inflammatory insults. The participation of ecSOD in immune responses seems therefore intuitive, yet is poorly understood. In the present study, we utilized mice with varying levels of ecSOD activity to investigate the involvement of this enzyme in immune responses against Listeria monocytogenes. Surprisingly, our data demonstrate that, despite enhanced neutrophil recruitment to the liver, ecSOD activity negatively impacted host survival and bacterial clearance. Increased ecSOD activity was accompanied by decreased co-localization of neutrophils with bacteria, as well as increased neutrophil apoptosis, which reduced overall and neutrophil-specific TNF-α production. Liver leukocytes from mice lacking ecSOD produced equivalent nitric oxide (NO·) when compared to mice expressing ecSOD. However, during infection, there were higher levels of peroxynitrite (NO3·−) in livers from mice lacking ecSOD compared to mice expressing ecSOD. Neutrophil depletion studies revealed that high levels of ecSOD activity resulted in neutrophils with limited protective capacity, whereas neutrophils from mice lacking ecSOD provided superior protection compared to neutrophils from wild-type mice. Taken together, our data demonstrate that ecSOD activity reduces innate immune responses during bacterial infection and provides a potential target for therapeutic intervention. PMID:22393157

Organic geochemical studies of modern microbial mats from Shark Bay: Part I: Influence of depth and salinity on lipid biomarkers and their isotopic signatures.

PubMed

Pagès, A; Grice, K; Ertefai, T; Skrzypek, G; Jahnert, R; Greenwood, P

2014-09-01

The present study investigated the influence of abiotic conditions on microbial mat communities from Shark Bay, a World Heritage area well known for a diverse range of extant mats presenting structural similarities with ancient stromatolites. The distributions and stable carbon isotopic values of lipid biomarkers [aliphatic hydrocarbons and polar lipid fatty acids (PLFAs)] and bulk carbon and nitrogen isotope values of biomass were analysed in four different types of mats along a tidal flat gradient to characterize the microbial communities and systematically investigate the relationship of the above parameters with water depth. Cyanobacteria were dominant in all mats, as demonstrated by the presence of diagnostic hydrocarbons (e.g. n-C17 and n-C17:1). Several subtle but important differences in lipid composition across the littoral gradient were, however, evident. For instance, the shallower mats contained a higher diatom contribution, concordant with previous mat studies from other locations (e.g. Antarctica). Conversely, the organic matter (OM) of the deeper mats showed evidence for a higher seagrass contribution [high C/N, 13C-depleted long-chain n-alkanes]. The morphological structure of the mats may have influenced CO2 diffusion leading to more 13C-enriched lipids in the shallow mats. Alternatively, changes in CO2 fixation pathways, such as increase in the acetyl COA-pathway by sulphate-reducing bacteria, could have also caused the observed shifts in δ13C values of the mats. In addition, three smooth mats from different Shark Bay sites were analysed to investigate potential functional relationship of the microbial communities with differing salinity levels. The C25:1 HBI was identified in the high salinity mat only and a lower abundance of PLFAs associated with diatoms was observed in the less saline mats, suggesting a higher abundance of diatoms at the most saline site. Furthermore, it appeared that the most and least saline mats were dominated by autotrophic biomass using different CO2 fixation pathways. © 2014 John Wiley & Sons Ltd.

Using Intact Iron Microbial Mats to Gain Insights Into Mat Ecology and Geochemical Niche at the Microbial Scale

NASA Astrophysics Data System (ADS)

Glazer, B. T.; Chan, C. S. Y.; Mcallister, S.; Leavitt, A.; Emerson, D.

2015-12-01

Microbial mats are formed by microorganisms working in coordinated symbiosis, often benefitting the community by controlling the local geochemical or physical environment. Thus, the ecology of the mat depends on the individual roles of microbes organized into niches within a larger architecture. Chemolithotrophic Fe-oxidizing bacteria (FeOB) form distinctive Fe oxyhydroxide biominerals which constitute the building blocks of the mat. However, the majority of our progress has been in understanding the overall community structure. Understanding the physical mat structure on the microbial scale is important to unraveling FeOB evolution, the biogeochemistry and ecology of Fe-rich habitats, and ultimately interpreting FeOB biosignatures in the rock record. Mats in freshwater and marine environments contain strikingly similar biomineral morphologies, yet they are formed by phylogenetically distinct microorganisms. This suggests that the overall architecture and underlying genetics of freshwater and marine mats has evolved to serve particular roles specific to Fe oxidation. Thus, we conducted a comparative study of Fe seep freshwater mats and marine hydrothermal mats. We have developed a new approach to sampling Fe mats in order to preserve the delicate structure for analysis by confocal and scanning electron microscopy. Our analyses of these intact mats show that freshwater and marine mats are similarly initiated by a single type of structure-former. These ecosystem engineers form either a hollow sheath or a twisted stalk biomineral during mat formation, with a highly directional structure. These microbes appear to be the vanguard organisms that anchor the community within oxygen/Fe(II) gradients, further allowing for community succession in the mat interior as evidenced by other mineralized morphologies. Patterns in biomineral thickness and directionality were indicative of redox gradients and temporal changes in the geochemical environment. These observations show that the FeOB create the structure of the environment for the entire microbial community, acting as environmental engineers. Furthermore, they leave behind distinctive signatures of environmental conditions (e.g. presence of oxygen, hydrothermal pulsing), which can be recorded in the rock record.

Use of palm-mat geotextiles for rainsplash erosion control

NASA Astrophysics Data System (ADS)

Bhattacharyya, R.; Fullen, M. A.; Davies, K.; Booth, C. A.

2010-07-01

Soil detachment by raindrop action (rainsplash erosion) is a very important subprocess of erosion by water. It is a particular problem in the UK as most soils are sandy or loamy sand in texture and lands have gentle to medium slope. However, few studies report potential rainsplash erosion control options under field conditions. Hence, the utilization of palm-mat geotextiles as a rainsplash erosion control technique was investigated at Hilton, east Shropshire, U.K. (52°33'5.7″ N, 2°19'18.3″ W). Geotextile-mats constructed from Borassus aethiopum (Borassus palm of West Africa) and Mauritia flexuosa (Buriti palm of South America) leaves are termed Borassus mats and Buriti mats, respectively. Two-year field experiments were conducted at Hilton to study the effects of emplacing Borassus and Buriti mats on rainsplash erosion of a loamy sand soil. Two sets (12 plots each) of experiments were established to study the effects of these mats on splash height and splash erosion. Splash height needs to be known to assess the transport mechanism of major soil fraction and its constituents on sloping land by rainsplash. In both sets, six randomly-selected plots were covered with mats, and the rest were bare. Results (during 22/01/2007‒23/01/2009; total precipitation = 1731.5 mm) show that Borassus mat-covered plots had ˜ 89% ( P < 0.001) less total splash erosion (2.97 kg m - 2 ) than bare plots (27.02 kg m - 2 ). Comparatively, mean splash height from Borassus mat-covered plots (0.12 m) was significantly ( P < 0.001) less than the bare plots, by ˜ 54%. However, Buriti mat-cover on bare plots had no significant ( P > 0.05) effect in rainsplash erosion control during that period, although plots with Buriti mats significantly ( P < 0.05) decreased splash height (by ˜ 18%) compared with bare plots (0.26 m). Buriti mats, probably due to their ˜ 43, 62 and 50% lower cover percentage (44%), mass per unit area (413 g - 2 ) and thickness (10 mm), respectively, compared with Borassus mats, were not effective in rainsplash erosion control. Both mats did not significantly ( P > 0.05) improve selected soil properties (i.e., soil organic matter, particle size distribution, aggregate stability and total soil carbon) as soil organic matter (SOM) input from mat-decomposition was much less than total SOM content. However, the changes in fine and medium sand contents (after 2 years) in the Borassus covered plots were significantly ( P < 0.05; n = 6) related to the total rainsplash erosion during 2007‒2009. Emplacement of Borassus and Buriti mats on bare soils did not decrease SOM contents after 2 years, indicating that improvements in some soil properties might occur over longer durations. After ˜ 10 months, Buriti mats lost ˜ 70% of their initial weight ( P < 0.001) and their initial cover percentage ( C, %) decreased drastically ( P < 0.05); whereas, Borassus mats maintained similar C to the initial condition, although mass per unit area decreased by ˜ 20% ( P < 0.05). Moreover, the functional longevity of Borassus mats was ˜ 2 years against only 1 year for Buriti mats. Hence, use of Borassus mats is highly effective for rainsplash erosion control in the UK.

Modulation of learning and memory by the genetic disruption of circadian oscillator populations.

PubMed

Snider, Kaitlin H; Obrietan, Karl

2018-06-23

While a rich literature has documented that the efficiency of learning and memory varies across circadian time, a close survey of that literature reveals extensive heterogeneity in the time of day (TOD) when peak cognitive performance occurs. Moreover, most previous experiments in rodents have not focused on the question of discriminating which memory processes (e.g., working memory, memory acquisition, or retrieval) are modulated by the TOD. Here, we use assays of contextual fear conditioning and spontaneous alternation in WT (C57Bl/6 J) mice to survey circadian modulation of hippocampal-dependent memory at multiple timescales - including working memory (seconds to a few minutes), intermediate-term memory (a delay of thirty minutes), and acquisition and retrieval of long-term memory (a delay of two days). Further, in order to test the relative contributions of circadian timing mechanisms to the modulation of memory, a parallel set of studies were performed in mice lacking clock timing mechanisms. These transgenic mice lacked the essential circadian gene Bmal1, either globally (Bmal1 null) or locally (floxed Bmal1 mice which lack Bmal1 in excitatory forebrain neurons, e.g. cortical and hippocampal neurons). Here, we show that in WT mice, retrieval (but not working memory, intermediate-term memory, or acquisition of long-term memory) is modulated by TOD. However, transgenic mouse models lacking Bmal1 - both globally, and only in forebrain excitatory neurons - show deficits regardless of the memory process tested (and lack circadian modulation of retrieval). These results provide new clarity regarding the impact of TOD on hippocampal-dependent memory and support the key role of hippocampal and cortical circadian oscillations in circadian gating of cognition. Copyright © 2018. Published by Elsevier Inc.

Analysis of multiple positive feedback paradigms demonstrates a complete absence of LH surges and GnRH activation in mice lacking kisspeptin signaling.

PubMed

Dror, Tal; Franks, Jennifer; Kauffman, Alexander S

2013-06-01

Kisspeptin stimulates gonadotropin-releasing hormone (GnRH) neurons via the kisspeptin receptor, Kiss1r. In rodents, estrogen-responsive kisspeptin neurons in the rostral hypothalamus have been postulated to mediate estrogen-induced positive feedback induction of the preovulatory luteinizing hormone (LH) surge. However, conflicting evidence exists regarding the ability of mice lacking Kiss1r to display LH surges in response to exogenous hormones. Whether the discrepancy reflects different mouse strains used and/or utilization of different surge-induction paradigms is unknown. Here, we tested multiple hormonal paradigms in one Kiss1r knockout (KO) model to see which paradigms, if any, could generate circadian-timed LH surges. Kiss1r KO and wild-type (WT) females were ovariectomized, given sex steroids in various modes, and assessed several days later for LH levels in the morning or evening (when surges occur). Serum LH levels were very low in all morning animals, regardless of genotype or hormonal paradigm. In each paradigm, virtually all WT females displayed clear LH surges in the evening, whereas none of the KO females demonstrated LH surges. The lack of LH surges in KO mice reflects a lack of GnRH secretion rather than diminished pituitary responsiveness from a lifetime lack of GnRH exposure because KO mice responded to GnRH priming with robust LH secretion. Moreover, high cfos-GnRH coexpression was detected in WT females in the evening, whereas low cfos-GnRH coexpression was present in KO females at all time points. Our findings conclusively demonstrate that WT females consistently display LH surges under multiple hormonal paradigms, whereas Kiss1r KO mice do not, indicating that kisspeptin-Kiss1r signaling is mandatory for GnRH/LH surge induction.

Disruption of NAD(P)H:quinone oxidoreductase 1 gene in mice leads to radiation induced myeloproliferative disease

PubMed Central

Iskander, Karim; Barrios, Roberto J.; Jaiswal, Anil K.

2008-01-01

NAD(P)H:quinone oxidoreductase1-null (NQO1-/-) mice exposed to 3 grays of γ-radiation demonstrated an increase in neutrophils, bone marrow hypercellularity, and enlarged lymph nodes and spleen. The spleen showed disrupted follicular structure, loss of red pulp, and granulocyte and megakarocyte invasion. Blood and histological analysis did not show any sign of infection in mice. These results suggested that exposure of NQO1-/- mice to γ-radiation led to myeloproliferative disease. Radiation-induced myeloproliferative disease was observed in 74% of NQO1-/- mice as compared to none in wild type mice. NQO1-/- mice exposed to γ-radiation also demonstrated tissues lymphoma (32%) and lung adenocarcinoma (84%). In contrast, only 11% wild type mice showed lymphoma and none showed lung adenocarcinoma. Exposure of NQO1-/- mice to γ-radiation resulted in reduced apoptosis in granulocytes and lack of induction of p53, p21, and Bax. NQO1-/- mice also demonstrated increased expression of myeloid differentiation factors C/EBPα and Pu.1. Intriguingly, exposure of NQO1-/- mice to γ-radiation failed to induce C/EBPα and Pu.1, as was observed in wild type mice. These results suggest that decreased p53/apoptosis and increased Pu.1 and C/EBPα led to myeloid hyperplasia in NQO1-/- mice. The lack of induction of apoptosis and differentiation contributed to radiation-induced myeloproliferative disease in NQO1-/- mice. PMID:18829548

Dynamics of archaea at fine spatial scales in Shark Bay mat microbiomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wong, Hon Lun; Visscher, Pieter T.; White, III, Richard Allen

Modern microbial mats provide remarkable insights into assembly, function and origin of complex microbial ecosystems. An excellent model of such systems is located in Shark Bay, Australia. Although bacteria have been extensively investigated in these communities, the role of archaea in microbial mats is poorly understood. Delineating the spatial distribution of archaea with mat depth will enable resolution of specific niches associated with this domain. In the present study, high throughput amplicon sequencing was undertaken in conjunction with key biogeochemical properties of two mat types (smooth and pustular). A total of 13,547,552 unfiltered sequences were obtained, and classified sequences weremore » affiliated to three archaeal and candidate phyla, Parvarchaeota, Euryarchaeota and Crenarchaeota. One way analysis of similarity tests (ANOSIM) indicated the archaeal community structures of smooth and pustular mats were significantly different (global R = 1, p = 0.1 %). Smooth mats possessed higher archaeal diversity, dominated by Parvarchaeota, followed by Thermoplasmata, Class marine benthic group B and Halobacteria. The methanogenic community in smooth mats was dominated by hydrogenotrophic Methanomicrobiales, as well as methylotrophic Methanosarcinales, Methanococcales, Methanobacteriales and Methanomassiliicoccaceae. Conversely, pustular mats were enriched with Halobacteria and Parvarchaeota. The rates of oxygen production/consumption as well as sulphate reduction were up to four times higher in smooth than in pustular mats. Methane production peaked in the oxic part of mats and was up to seven-fold higher in smooth than in pustular mats. Metabolic cooperation in putative surface anoxic niches is proposed to be key in efficient cycling of key nutrients in these systems.« less

Evaluation of polyacrylonitrile electrospun nano-fibrous mats as leukocyte removal filter media.

PubMed

Pourbaghi, Raha; Zarrebini, Mohammad; Semnani, Dariush; Pourazar, Abbasali; Akbari, Nahid; Shamsfar, Reihaneh

2018-07-01

Removal of leukocytes from blood products is the most effective means for elimination of undesirable side effects and prevention of possible reactions in recipients. Micro-fibrous mats are currently used for removal of leukocytes from blood. In this study, samples of electrospun nano-fibrous mats were produced. The performance of the produced electrospun nano-fibrous mats as means of leukocytes removal from fresh whole blood was both evaluated and compared with that of commercially available micro-fibrous mats. In order to produce the samples, polyacrylonitrile (PAN) nano-fibrous mats were made under different electrospinning conditions. Mean fiber diameter, pore characterization and surface roughness of the PAN nano-fibrous mats were determined using image processing technique. In order to evaluate the surface tension of the fabricated mats, water contact angle was measured. The leukocyte removal performance, erythrocytes recovery percent and hemolysis rate of the nano-fibrous mats were compared. The effectiveness of nano-fibrous mats in removing leukocyte was established using both scanning electron microscope and optical microscope. Results showed that for given weight, the fabricated nano-fibrous mats were not only more efficient but also more cost-effective than their commercial counterparts. Results confirmed that changes in mean fiber diameter, the number of layer and weight of each layer in the absence of any chemical reaction or physical surface modification, the fabricated nano-fibrous mats were able to remove 5-log of leukocytes. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1759-1769, 2018. © 2017 Wiley Periodicals, Inc.

Dynamics of archaea at fine spatial scales in Shark Bay mat microbiomes

DOE PAGES

Wong, Hon Lun; Visscher, Pieter T.; White, III, Richard Allen; ...

2017-04-11

Modern microbial mats provide remarkable insights into assembly, function and origin of complex microbial ecosystems. An excellent model of such systems is located in Shark Bay, Australia. Although bacteria have been extensively investigated in these communities, the role of archaea in microbial mats is poorly understood. Delineating the spatial distribution of archaea with mat depth will enable resolution of specific niches associated with this domain. In the present study, high throughput amplicon sequencing was undertaken in conjunction with key biogeochemical properties of two mat types (smooth and pustular). A total of 13,547,552 unfiltered sequences were obtained, and classified sequences weremore » affiliated to three archaeal and candidate phyla, Parvarchaeota, Euryarchaeota and Crenarchaeota. One way analysis of similarity tests (ANOSIM) indicated the archaeal community structures of smooth and pustular mats were significantly different (global R = 1, p = 0.1 %). Smooth mats possessed higher archaeal diversity, dominated by Parvarchaeota, followed by Thermoplasmata, Class marine benthic group B and Halobacteria. The methanogenic community in smooth mats was dominated by hydrogenotrophic Methanomicrobiales, as well as methylotrophic Methanosarcinales, Methanococcales, Methanobacteriales and Methanomassiliicoccaceae. Conversely, pustular mats were enriched with Halobacteria and Parvarchaeota. The rates of oxygen production/consumption as well as sulphate reduction were up to four times higher in smooth than in pustular mats. Methane production peaked in the oxic part of mats and was up to seven-fold higher in smooth than in pustular mats. Metabolic cooperation in putative surface anoxic niches is proposed to be key in efficient cycling of key nutrients in these systems.« less

Long survival and immunologic reconstitution following transplantation with syngeneic or allogeneic fetal liver and neonatal spleen cells. [X radiation, mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yunis, E.J.; Fernandes, G.; Smith, J.

1976-12-01

Spleen cells from newborn syngeneic and allogeneic mice that lack fully differentiated T lymphocytes can be used as a hematopoietic source to reconstitute both hematopoietic and lymphoid systems of lethally irradiated mice without producing a GVHR. Fetal liver cells from syngeneic and allogeneic mice that lack postthymic T lymphocytes can also be used for hematopoietic and immunologic reconstitution of lethally irradiated mice without producing GVHR. Immunologic deficiency is observed in some experiments in mice given supralethal irradiation (1000 R) and fetal liver as reconstituting hematopoietic tissue. The findings suggest that T cells, at an early stage of differentiation, are moremore » susceptible to tolerance induction than are T lymphocytes at later stages of differentiation and do not, in general, produce GVHR. It is postulated that hematopoietic cells, free of postthymic lymphoid cells, can be used for hematopoietic or immunologic reconstitution and celular engineering without producing GVHD.« less

In vivo preservation of steroid specificity in CWR22 xenografts having a mutated androgen receptor.

PubMed

Shao, Tsang C; Li, Huiling; Eid, Wael; Ittmann, Michael; Unni, Emmanual; Cunningham, Glenn R

2003-09-15

In vitro studies of CWR22 tumor cells lack steroid specificity. We sought to determine if CWR22 xenografts also lack steroid specificity. We injected castrated nude mice with CWR22 tumor cells (6 x 10(6) cells) and implanted Alzet osmotic pumps that delivered approximately 1 mg steroid/kg body weight/day. Serum PSA levels were detectable in intact mice and castrated mice treated with testosterone (T), but not in those treated with estradiol (E(2)), progesterone (P), or flutamide (F). T maintained mean tumor weight similar to that in intact mice (P = NS). We observed no tumors in castrated mice or mice treated with E(2), P, or F, and tumor histology was consistent with weights. The mutation of the androgen receptor (H874Y) that occurs in the CWR22 xenograft model of human prostate cancer does not significantly affect in vivo steroid specificity for E(2), P, or F. Copyright 2003 Wiley-Liss, Inc.

Sleep apneas are increased in mice lacking monoamine oxidase A.

PubMed

Real, Caroline; Popa, Daniela; Seif, Isabelle; Callebert, Jacques; Launay, Jean-Marie; Adrien, Joëlle; Escourrou, Pierre

2007-10-01

Alterations in the serotonin (5-HT) system have been suggested as a mechanism of sleep apnea in humans and rodents. The objective is to evaluate the contribution of 5-HT to this disorder. We studied sleep and breathing (whole-body plethysmography) in mutant mice that lack monoamine oxidase A (MAOA) and have increased concentrations of monoamines, including 5-HT. Compared to wild-type mice, the mutants showed similar amounts of slow wave sleep (SWS) and rapid eye movement sleep (REMS), but exhibited a 3-fold increase in SWS and REMS apnea indices. Acute administration of the MAOA inhibitor clorgyline decreased REMS amounts and increased the apnea index in wild-type but not mutant mice. Parachlorophenylalanine, a 5-HT synthesis inhibitor, reduced whole brain concentrations of 5-HT in both strains, and induced a decrease in apnea index in mutant but not wild-type mice. Our results show that MAOA deficiency is associated with increased sleep apnea in mice and suggest that an acute or chronic excess of 5-HT contributes to this phenotype.

Graft extrusion in both the coronal and sagittal planes is greater after medial compared with lateral meniscus allograft transplantation but is unrelated to early clinical outcomes.

PubMed

Lee, Dae-Hee; Lee, Chang-Rack; Jeon, Jin-Ho; Kim, Kyung-Ah; Bin, Seong-Il

2015-01-01

Graft extrusion after meniscus allograft transplantation (MAT) may be affected by horn fixation, which differs between medial and lateral MAT. Few studies have compared graft extrusion, especially sagittal extrusion, after medial and lateral MAT. In patients undergoing medial and lateral MAT, graft extrusion is likely similar and not correlated with postoperative Lysholm scores. Cohort study; Level of evidence, 2. Meniscus graft extrusion in the coronal and sagittal planes was compared in 51 knees undergoing medial MAT and 84 undergoing lateral MAT. Distances from the anterior and posterior articular cartilage margins to the anterior (anterior cartilage meniscus distance [ACMD]) and posterior (posterior cartilage meniscus distance [PCMD]) horns, respectively, were assessed on immediate postoperative magnetic resonance imaging and compared in patients undergoing medial and lateral MAT. Correlations between coronal and sagittal graft extrusion and between extrusion and the Lysholm score were compared in the 2 groups. In the coronal plane, mean absolute (4.3 vs 2.7 mm, respectively; P<.001) and relative (39% vs 21%, respectively; P<.001) graft extrusions were significantly greater for medial than lateral MAT. In the sagittal plane, mean absolute and relative ACMD and PCMD values were significantly greater for medial than lateral MAT (P<.001 each). For both medial and lateral MAT, mean absolute and relative ACMDs were significantly larger than PCMDs (P<.001 each). Graft extrusion>3 mm in the coronal plane was significantly more frequent in the medial (78%) than in the lateral (35%) MAT group. In the sagittal plane, the frequencies of ACMDs (72% vs 39%, respectively) and PCMDs (23% vs 4%, respectively) >3 mm were also significantly greater in the medial than in the lateral MAT group. Coronal and sagittal extrusions were not correlated with postoperative Lysholm scores for both medial and lateral MAT. The amount and incidence of graft extrusion were greater after medial than lateral MAT in both the coronal and sagittal planes. In the sagittal plane, graft extrusion was greater and more frequent on the anterior than the posterior horn in both medial and lateral MAT. However, graft extrusion was not correlated with early clinical outcomes after both medial and lateral MAT. © 2014 The Author(s).

Electrospun polyvinylpyrrolidone (PVP)/green tea extract composite nanofiber mats and their antioxidant activities

NASA Astrophysics Data System (ADS)

Pusporini, Pusporini; Edikresnha, Dhewa; Sriyanti, Ida; Suciati, Tri; Miftahul Munir, Muhammad; Khairurrijal, Khairurrijal

2018-05-01

Electrospinning was employed to make PVP (polyvinylpyrrolidone)/GTE (green tea extract) composite nanofiber mats. The electrospun PVP nanofiber mat as well as the PVP/GTE nanofiber mats were uniform. The average fiber diameter of PVP/GTE composite nanofiber mat decreased with increasing the GTE weight fraction (or decreasing the PVP weight fraction) in the PVP/GTE solution because the PVP/GTE solution concentration decreased. Then, the broad FTIR peak representing the stretching vibrations of O–H in hydroxyl groups of phenols and the stretching of N–H in amine groups of the GTE paste shifted to higher wavenumbers in the PVP/GTE composite nanofiber mats. These peak shifts implied that PVP and catechins of GTE in the PVP/GTE composite nanofiber mats had intermolecular interactions via hydrogen bonds between carbonyl groups of PVP and hydroxyl groups of catechins in GTE. Lastly, the antioxidant activity of the PVP/GTE composite nanofiber mat increased with reducing the average fiber diameter because the amount of catechins in the composite nanofiber mat increased with the increase of surface area due to the reduction of the average fiber diameter.

Absence of opioid stress-induced analgesia in mice lacking beta-endorphin by site-directed mutagenesis.

PubMed Central

Rubinstein, M; Mogil, J S; Japón, M; Chan, E C; Allen, R G; Low, M J

1996-01-01

A physiological role for beta-endorphin in endogenous pain inhibition was investigated by targeted mutagenesis of the proopiomelanocortin gene in mouse embryonic stem cells. The tyrosine codon at position 179 of the proopiomelanocortin gene was converted to a premature translational stop codon. The resulting transgenic mice display no overt developmental or behavioral alterations and have a normally functioning hypothalamic-pituitary-adrenal axis. Homozygous transgenic mice with a selective deficiency of beta-endorphin exhibit normal analgesia in response to morphine, indicating the presence of functional mu-opiate receptors. However, these mice lack the opioid (naloxone reversible) analgesia induced by mild swim stress. Mutant mice also display significantly greater nonopioid analgesia in response to cold water swim stress compared with controls and display paradoxical naloxone-induced analgesia. These changes may reflect compensatory upregulation of alternative pain inhibitory mechanisms. Images Fig. 1 Fig. 2 PMID:8633004

Aerobic sulfate reduction in microbial mats

NASA Technical Reports Server (NTRS)

Canfield, Donald E.; Des Marais, David J.

1991-01-01

Measurements of bacterial sulfate reduction and dissolved oxygen (O2) in hypersaline bacterial mats from Baja California, Mexico, revealed that sulfate reduction occurred consistently within the well-oxygenated photosynthetic zone of the mats. This evidence that dissimilatory sulfate reduction can occur in the presence of O2 challenges the conventional view that sulfate reduction is a strictly anaerobic process. At constant temperature, the rates of sulfate reduction in oxygenated mats during daytime were similar to rates in anoxic mats at night: thus, during a 24-hour cycle, variations in light and O2 have little effect on rates of sulfate reduction in these mats.

Sensitometric and archival evaluation of Kodak RA films in dental automatic processing.

PubMed

Thunthy, K H; Yeadon, W R; Winberg, R

1994-04-01

The Kodak Rapid Access System is an extension of the T-grain technology (T-Mat film). Unlike the T-Mat film, the T-Mat/Rapid Access film is forehardened by the addition of more hardener to the film emulsion. It can thus be processed rapidly in a Kodak Rapid Access medical processor in only 45 seconds dry-to-dry cycle by using the Kodak X-Omat RA/30 developer that does not contain a hardener. The absence of the hardener, glutaraldehyde, in the developer also makes this solution environmentally safer. In medical radiography, the T-Mat film has been replaced by the T-Mat/Rapid Access film. However, in dental extraoral radiography the T-Mat film is still being used because the processing solutions and the comparatively low temperatures of dental automatic processors are different from those used in medical radiography. This report shows that, for panoramic and other dental extraoral radiography, T-Mat films can be replaced by T-Mat/RA films by processing them in conventional Kodak X-Omat RP solutions using a dental automatic processing cycle. The differences in the sensitometric properties of the T-Mat and T-Mat/rapid Access films were negligible and therefore clinically insignificant. All films tested well for archival quality.

Lack of phosphatidylethanolamine N-methyltransferase in mice does not promote fatty acid oxidation in skeletal muscle.

PubMed

Tasseva, Guergana; van der Veen, Jelske N; Lingrell, Susanne; Jacobs, René L; Vance, Dennis E; Vance, Jean E

2016-02-01

Phosphatidylethanolamine N-methyltransferase (PEMT) converts phosphatidylethanolamine (PE) to phosphatidylcholine (PC) in the liver. Mice lacking PEMT are protected from high-fat diet-induced obesity and insulin resistance, and exhibit increased whole-body energy expenditure and oxygen consumption. Since skeletal muscle is a major site of fatty acid oxidation and energy utilization, we determined if rates of fatty acid oxidation/oxygen consumption in muscle are higher in Pemt(-/-) mice than in Pemt(+/+) mice. Although PEMT is abundant in the liver, PEMT protein and activity were undetectable in four types of skeletal muscle. Moreover, amounts of PC and PE in the skeletal muscle were not altered by PEMT deficiency. Thus, we concluded that any influence of PEMT deficiency on skeletal muscle would be an indirect consequence of lack of PEMT in liver. Neither the in vivo rate of fatty acid uptake by muscle nor the rate of fatty acid oxidation in muscle explants and cultured myocytes depended upon Pemt genotype. Nor did PEMT deficiency increase oxygen consumption or respiratory function in skeletal muscle mitochondria. Thus, the increased whole body oxygen consumption in Pemt(-/-) mice, and resistance of these mice to diet-induced weight gain, are not primarily due to increased capacity of skeletal muscle for utilization of fatty acids as an energy source. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Reduction of renal mass is lethal in mice lacking vimentin. Role of endothelin-nitric oxide imbalance.

PubMed Central

Terzi, F; Henrion, D; Colucci-Guyon, E; Federici, P; Babinet, C; Levy, B I; Briand, P; Friedlander, G

1997-01-01

Modulation of vascular tone by chemical and mechanical stimuli is a crucial adaptive phenomenon which involves cytoskeleton elements. Disruption, by homologous recombination, of the gene encoding vimentin, a class III intermediate filament protein mainly expressed in vascular cells, was reported to result in apparently normal phenotype under physiological conditions. In this study, we evaluated whether the lack of vimentin affects vascular adaptation to pathological situations, such as reduction of renal mass, a pathological condition which usually results in immediate and sustained vasodilation of the renal vascular bed. Ablation of 3/4 of renal mass was constantly lethal within 72 h in mice lacking vimentin (Vim-/-), whereas no lethality was observed in wild-type littermates. Death in Vim-/- mice resulted from end-stage renal failure. Kidneys from Vim-/- mice synthesized more endothelin, but less nitric oxide (NO), than kidneys from normal animals. In vitro, renal resistance arteries from Vim-/- mice were selectively more sensitive to endothelin, less responsive to NO-dependent vasodilators, and exhibited an impaired flow (shear stress)- induced vasodilation, which is NO dependent, as compared with those from normal littermates. Finally, in vivo administration of bosentan, an endothelin receptor antagonist, totally prevented lethality in Vim-/- mice. These results suggest that vimentin plays a key role in the modulation of vascular tone, possibly via the tuning of endothelin-nitric oxide balance. PMID:9294120

Spatially-resolved carbon flow through a hypersaline phototrophic microbial mat

NASA Astrophysics Data System (ADS)

Moran, J.; Lindemann, S. R.; Cory, A. B.; Courtney, S.; Cole, J. K.; Fredrickson, J.

2013-12-01

Hot Lake is a hypersaline, meromictic lake located in an endorheic basin in north-central Washington. Low annual rainfall and high evaporation rates contribute to the lake's high salinity. The predominant dissolved salt is magnesium sulfate, of which monimolimnion waters may seasonally exceed 2 M concentrations. Induced by its high salinity and meromictic nature, Hot Lake displays an inverse thermal gradient with deep horizons seasonally exceeding 50 °C. Despite extreme conditions, dense benthic microbial mats composed of cyanobacteria, anoxygenic photoheterotrophs, and bacterial heterotroph populations develop in the lake. These mats can exceed 1 cm in thickness and display vertical stratification in color due to bacterial pigmentation. Typical mat stratification includes an orange surface layer underlain by green and purple layers at increasing depth. Carbonates, including aragonite and magnesite, are observed within the mat and their formation is likely induced or influenced by microbial metabolic activities and associated pH excursions. We are exploring the role Hot Lake's microbial mats play in carbon cycling. Cyanobacteria are the dominant CO2-fixing organisms in the mat and we seek to understand the spatial and metabolic controls on how the carbon initially fixed by mat cyanobacteria is transferred to associated heterotrophic populations spread throughout the mat strata. Secondly, we seek to understand the overall net carbon balance of the mat through a growing season. We are using a stable isotope probing approach for assessing carbon uptake and migration through representative mat samples. We performed a series of ex situ incubations of freshly harvested mat samples in lake water amended with 13C-labeled bicarbonate or substrates commonly consumed by heterotrophs (including acetate and glucose) and using multiple stable isotope techniques to track label uptake, residence time, remineralization, and location within the mat. In addition to bulk isotope analysis (via elemental analysis IRMS and gas bench IRMS) we are employing laser ablation IRMS (LA-IRMS) to provide a spatially-resolved accounting of label uptake through the mat cross section. This technique permits isotope analysis at the 50 μm scale, and can provide multiple isotope analyses within each mat strata. By coupling LA-IRMS analysis with laminar sectioning of the mat and amplicon sequencing of the rrnA gene, we seek to establish linkages between phylogeny and function over the course of a diel cycle with highlighted emphasis on evidence of carbon transfer between mat laminae and the phylotypes that inhabit them. We are also using a series of carbon accumulation microcosms to quantify net carbon fixation over the seasonal cycle. These microcosms are deployed at multiple depths to provide an accounting of carbon cycling under the specific geochemical conditions experienced at variable depth. Coupling the data from these individual microcosms to our bathymetric survey of Hot Lake permits us to estimate total mat carbon fixation, and therefore to begin to assess the impact of the mat on the greater lake carbon cycle.

Impaired ventilatory acclimatization to hypoxia in mice lacking the immediate early gene fos B.

PubMed

Malik, Mohammad T; Peng, Ying-Jie; Kline, David D; Adhikary, Gautam; Prabhakar, Nanduri R

2005-01-15

Earlier studies on cell culture models suggested that immediate early genes (IEGs) play an important role in cellular adaptations to hypoxia. Whether IEGs are also necessary for hypoxic adaptations in intact animals is not known. In the present study we examined the potential importance of fos B, an IEG in ventilatory acclimatization to hypoxia. Experiments were performed on wild type and mutant mice lacking the fos B gene. Ventilation was monitored by whole body plethysmography in awake animals. Baseline ventilation under normoxia, and ventilatory response to acute hypoxia and hypercapnia were comparable between wild type and mutant mice. Hypobaric hypoxia (0.4 atm; 3 days) resulted in a significant elevation of baseline ventilation in wild type but not in mutant mice. Wild type mice exposed to hypobaric hypoxia manifested an enhanced hypoxic ventilatory response compared to pre-hypobaric hypoxia. In contrast, hypobaric hypoxia had no effect on the hypoxic ventilatory response in mutant mice. Hypercapnic ventilatory responses, however, were unaffected by hypobaric hypoxia in both groups of mice. These results suggest that the fos B, an immediate early gene, plays an important role in ventilatory acclimatization to hypoxia in mice.

Immunological Development and Cardiovascular Function Are Normal in Annexin VI Null Mutant Mice

PubMed Central

Hawkins, Tim E.; Roes, Jürgen; Rees, Daryl; Monkhouse, Jayne; Moss, Stephen E.

1999-01-01

Annexins are calcium-binding proteins of unknown function but which are implicated in important cellular processes, including anticoagulation, ion flux regulation, calcium homeostasis, and endocytosis. To gain insight into the function of annexin VI, we performed targeted disruption of its gene in mice. Matings between heterozygous mice produced offspring with a normal Mendelian pattern of inheritance, indicating that the loss of annexin VI did not interfere with viability in utero. Mice lacking annexin VI reached sexual maturity at the same age as their normal littermates, and both males and females were fertile. Because of interest in the role of annexin VI in cardiovascular function, we examined heart rate and blood pressure in knockout and wild-type mice and found these to be identical in the two groups. Similarly, the cardiovascular responses of both sets of mice to septic shock were indistinguishable. We also examined components of the immune system and found no differences in thymic, splenic, or bone marrow lymphocyte levels between knockout and wild-type mice. This is the first study of annexin knockout mice, and the lack of a clear phenotype has broad implications for current views of annexin function. PMID:10567528

Maté: a risk factor for oral and oropharyngeal cancer.

PubMed

Goldenberg, David

2002-10-01

Maté is a tea-like beverage consumed mainly in Argentina, Uruguay, Paraguay, southern Brazil and to a lesser degree in other areas of the world such as Germany, Syria, Lebanon and Northern Israel. It is brewed from the dried leaves and stemlets of the perennial tree Ilex paraguarensis ("yerba mate") a species that belongs to the Aquifoliaceae family. Maté consumption has been associated with an increased rate of oral and oropharyngeal cancers. The purpose of this study is to review the literature and discuss the role of Maté consumption in the development of oral and oropharyngeal cancer and the potential carcinogenic mechanisms. A review of the relevant literature linking Maté consumption with oral and oropharyngeal cancer and the carcinogenicity of Maté was performed. The search was performed using Medline, library catalogues, OCLC first search and ISI web of science databases. Case control studies on Maté drinking populations and, in vivo and in vitro studies on the carcinogenicity of Maté were reviewed. The populations reviewed in many of these studies also used alcohol and tobacco products confounding the influence of Maté as an independent risk factor. There is evidence in the literature that Maté consumption is in itself carcinogenic and plays a role in the development of cancers of the oral cavity and oropharynx. Although the exact mechanism of carcinogenesis is still unknown, available information suggests that Maté drinking should be considered one of the risk factors for oral and oropharyngeal cancer.

Comparative protein modeling of methionine S-adenosyltransferase (MAT) enzyme from Mycobacterium tuberculosis: a potential target for antituberculosis drug discovery.

PubMed

Khedkar, Santosh A; Malde, Alpeshkumar K; Coutinho, Evans C

2005-01-01

Mycobacterium tuberculosis (Mtb) is a successful pathogen that overcomes the numerous challenges presented by the immune system of the host. In the last 40 years few anti-TB drugs have been developed, while the drug-resistance problem is increasing; there is thus a pressing need to develop new anti-TB drugs active against both the acute and chronic growth phases of the mycobacterium. Methionine S-adenosyltransferase (MAT) is an enzyme involved in the synthesis of S-adenosylmethionine (SAM), a methyl donor essential for mycolipid biosynthesis. As an anti-TB drug target, Mtb-MAT has been well validated. A homology model of MAT has been constructed using the X-ray structures of E. coli MAT (PDB code: 1MXA) and rat MAT (PDB code: 1QM4) as templates, by comparative protein modeling principles. The resulting model has the correct stereochemistry as gauged from the Ramachandran plot and good three-dimensional (3D) structure compatibility as assessed by the Profiles-3D score. The structurally and functionally important residues (active site) of Mtb-MAT have been identified using the E. coli and rat MAT crystal structures and the reported point mutation data. The homology model conserves the topological and active site features of the MAT family of proteins. The differences in the molecular electrostatic potentials (MEP) of Mtb and human MAT provide evidences that selective and specific Mtb-MAT inhibitors can be designed using the homology model, by the structure-based drug design approaches.

Transgenic Restoration of Urea Transporter A1 Confers Maximal Urinary Concentration in the Absence of Urea Transporter A3.

PubMed

Klein, Janet D; Wang, Yanhua; Mistry, Abinash; LaRocque, Lauren M; Molina, Patrick A; Rogers, Richard T; Blount, Mitsi A; Sands, Jeff M

2016-05-01

Urea has a critical role in urinary concentration. Mice lacking the inner medullary collecting duct (IMCD) urea transporter A1 (UT-A1) and urea transporter A3 (UT-A3) have very low levels of urea permeability and are unable to concentrate urine. To investigate the role of UT-A1 in the concentration of urine, we transgenically expressed UT-A1 in knockout mice lacking UT-A1 and UT-A3 using a construct with a UT-A1 gene that cannot be spliced to produce UT-A3. This construct was inserted behind the original UT-A promoter to yield a mouse expressing only UT-A1 (UT-A1(+/+)/UT-A3(-/-)). Western blot analysis demonstrated UT-A1 in the inner medulla of UT-A1(+/+)/UT-A3(-/-) and wild-type mice, but not in UT-A1/UT-A3 knockout mice, and an absence of UT-A3 in UT-A1(+/+)/UT-A3(-/-) and UT-A1/UT-A3 knockout mice. Immunohistochemistry in UT-A1(+/+)/UT-A3(-/-) mice also showed negative UT-A3 staining in kidney and other tissues and positive UT-A1 staining only in the IMCD. Urea permeability in isolated perfused IMCDs showed basal permeability in the UT-A1(+/+)/UT-A3(-/-) mice was similar to levels in wild-type mice, but vasopressin stimulation of urea permeability in wild-type mice was significantly greater (100% increase) than in UT-A1(+/+)/UT-A3(-/-) mice (8% increase). Notably, basal urine osmolalities in both wild-type and UT-A1(+/+)/UT-A3(-/-) mice increased upon overnight water restriction. We conclude that transgenic expression of UT-A1 restores basal urea permeability to the level in wild-type mice but does not restore vasopressin-stimulated levels of urea permeability. This information suggests that transgenic expression of UT-A1 alone in mice lacking UT-A1 and UT-A3 is sufficient to restore urine-concentrating ability. Copyright © 2016 by the American Society of Nephrology.

Transgenic Restoration of Urea Transporter A1 Confers Maximal Urinary Concentration in the Absence of Urea Transporter A3

PubMed Central

Wang, Yanhua; Mistry, Abinash; LaRocque, Lauren M.; Molina, Patrick A.; Rogers, Richard T.; Blount, Mitsi A.; Sands, Jeff M.

2016-01-01

Urea has a critical role in urinary concentration. Mice lacking the inner medullary collecting duct (IMCD) urea transporter A1 (UT-A1) and urea transporter A3 (UT-A3) have very low levels of urea permeability and are unable to concentrate urine. To investigate the role of UT-A1 in the concentration of urine, we transgenically expressed UT-A1 in knockout mice lacking UT-A1 and UT-A3 using a construct with a UT-A1 gene that cannot be spliced to produce UT-A3. This construct was inserted behind the original UT-A promoter to yield a mouse expressing only UT-A1 (UT-A1+/+/UT-A3−/−). Western blot analysis demonstrated UT-A1 in the inner medulla of UT-A1+/+/UT-A3−/− and wild-type mice, but not in UT-A1/UT-A3 knockout mice, and an absence of UT-A3 in UT-A1+/+/UT-A3−/− and UT-A1/UT-A3 knockout mice. Immunohistochemistry in UT-A1+/+/UT-A3−/− mice also showed negative UT-A3 staining in kidney and other tissues and positive UT-A1 staining only in the IMCD. Urea permeability in isolated perfused IMCDs showed basal permeability in the UT-A1+/+/UT-A3−/− mice was similar to levels in wild-type mice, but vasopressin stimulation of urea permeability in wild-type mice was significantly greater (100% increase) than in UT-A1+/+/UT-A3−/− mice (8% increase). Notably, basal urine osmolalities in both wild-type and UT-A1+/+/UT-A3−/− mice increased upon overnight water restriction. We conclude that transgenic expression of UT-A1 restores basal urea permeability to the level in wild-type mice but does not restore vasopressin-stimulated levels of urea permeability. This information suggests that transgenic expression of UT-A1 alone in mice lacking UT-A1 and UT-A3 is sufficient to restore urine-concentrating ability. PMID:26407594

Ethanol consumption in mice lacking CD14, TLR2, TLR4, or MyD88

PubMed Central

Blednov, Yuri A.; Black, Mendy; Chernis, Julia; Da Costa, Adriana; Mayfield, Jody; Harris, R. Adron

2016-01-01

Background Molecular and behavioral studies support a role for innate immune proinflammatory pathways in mediating the effects of alcohol. Increased levels of Toll-like receptors (TLRs) have been observed in animal models of alcohol consumption and in human alcoholics, and many of these TLRs signal via the MyD88-dependent pathway. We hypothesized that this pathway is involved in alcohol drinking and examined some of its key signaling components. Methods Different ethanol drinking paradigms were studied in male and female control C57BL/6J mice vs. mice lacking CD14, TLR2, TLR4 (C57BL/10ScN), or MyD88. We studied continuous and intermittent access two-bottle choice (2BC) and one-bottle and 2BC drinking-in-the-dark (DID) tests as well as preference for saccharin, quinine, and NaCl. Results In the 2BC continuous access test, ethanol intake decreased in male TLR2 knockout (KO) mice, and we previously reported reduced 2BC drinking in male and female CD14 KO mice. In the intermittent access 2BC test, ethanol intake decreased in CD14 KO male and female mice, whereas drinking increased in MyD88 KO male mice. In the 2BC-DID test, ethanol drinking decreased in male and female mice lacking TLR2, whereas drinking increased in MyD88 KO male mice. In the one-bottle DID test, ethanol intake decreased in female TLR2 KO mice. TLR2 KO and CD14 KO mice did not differ in saccharin preference but showed reduced preference for NaCl. MyD88 KO mice showed a slight reduction in preference for saccharin. Conclusions Deletion of key components of the MyD88-dependent pathway produced differential effects on ethanol intake by decreasing (TLR2 KO and CD14 KO) or increasing (MyD88 KO) drinking, while deletion of TLR4 had no effect. Some of the drinking effects depended on the sex of the mice and/or the ethanol-drinking model. PMID:28146272

Cold Temperature Encoding by Cutaneous TRPA1 and TRPM8-Carrying Fibers in the Mouse

PubMed Central

Winter, Zoltan; Gruschwitz, Philipp; Eger, Stephanie; Touska, Filip; Zimmermann, Katharina

2017-01-01

Previous research identified TRPM8 and TRPA1 cold transducers with separate functions, one being functional in the non-noxious range and the second one being a nociceptive transducer. TRPM8-deficient mice present overt deficits in the detection of environmental cool, but not a lack of cold avoidance and TRPA1-deficient mice show clear deficits in some cold nocifensive assays. The extent of TRPA1's contribution to cold sensing in vivo is still unclear, because mice lacking both TRPM8 and TRPA1 (DKO) were described with unchanged cold avoidance from TRPM8−/− based on a two-temperature-choice assay and by c-fos measurement. The present study was designed to differentiate how much TRPM8 alone and combined TRPA1 and TRPM8 contribute to cold sensing. We analyzed behavior in the thermal ring track assay adjusted between 30 and 5°C and found a large reduction in cold avoidance of the double knockout mice as compared to the TRPM8-deficient mice. We also revisited skin-nerve recordings from saphenous-nerve skin preparations with regard to nociceptors and thermoreceptors. We compared the frequency and characteristics of the cold responses of TRPM8-expressing and TRPM8-negative C-fiber nociceptors in C57BL/6J mice with nociceptors of TRPM8-deficient and DKO mice and found that TRPM8 enables nociceptors to encode cold temperatures with higher firing rates and larger responses with sustained, static component. In TRPM8−/−, C-fiber cold nociceptors were markedly reduced and appeared further reduced in DKO. Nevertheless, the remaining cold responses in both knockout strains were similar in their characteristics and they were indifferent from the TRPM8-negative cold responses found in C57BL/6J mice. TRPM8 had a comparably essential role for encoding cold in thermoreceptors and lack of TRPM8 reduced response magnitude, peak and mean firing rates and the incidence of thermoreceptors. The encoding deficits were similar in the DKO strain. Our data illustrate that lack of TRPA1 in TRPM8-deficient mice results in a disproportionately large reduction in cold avoidance behavior and also affects the incidence of cold encoding fiber types. Presumably TRPA1 compensates for lack of TRPM8 to a certain extent and both channels cooperate to cover the entire cold temperature range, making cold-temperature encoding by TRPA1—although less powerful—synergistic to TRPM8. PMID:28713241

Microbial and Functional Gene Diversity in the Thrombolitic Mats of Highborne Cay, Bahamas

NASA Astrophysics Data System (ADS)

Foster, J. S.; Mobberley, J. M.

2010-04-01

In this study we examine the metagenome of modern thrombolitic mats. Our results indicate that thrombolitic mats are far more diverse than previously assumed; and gene analysis is now elucidating the molecular pathways needed for thrombolitic mat development.

Topographic control of mat-surface structures evolution: Examples from modern evaporitic carbonate (Abu Dhabi) and evaporitic siliciclastic (Tunisia) tidal flats.

NASA Astrophysics Data System (ADS)

Hafid Bouougri, El; Porada, Hubertus

2010-05-01

In terms of optimal light utilization, mat surfaces ideally are flat. In nature, however, flat mat surfaces are observed rarely or in restricted patches only. Rather they are shaped by a variety of linear and subcircular to irregular protrusions at various scales, including overgrown upturned crack margins, bulges (‘petees'), domes (‘blisters' and ‘pustules'), reticulate networks with tufts and pinnacles etc. These features are so characteristic that ‘mat types' have been established according to their prevalence, e.g., film, flat, smooth, crinkle, blister, tufted, cinder, mammilate, pustular and polygonal mats (Kendall and Skipwith, 1969; Logan et al., 1974). Responsible for the development of such mat surface features are environmental (physical and chemical) factors and, in reaction, the opportunistic growth behaviour of the participating bacterial taxa. Theoretically, a ‘juvenile' mat may be assumed as being flat, evolving into various forms with typical surface morphologies according to environmental impacts and respective bacterial reactions. Observations in the Abu Dhabi evaporitic carbonate tidal flats and Tunisian evaporitic siliciclastic tidal flats demonstrate that topography plays a fundamental role, both on the large scale of the tidal flat and on the small scale of mat surface morphology. It controls, together with related factors like, e.g., frequency of tidal flooding; duration of water cover; frequency and duration of subaerial exposure, the spatial distribution and the temporal evolution of mat surface structures. On the tidal flat scale, topographic differences result a priori from its seaward gradient and may arise additionally from physical processes which may modify the substrate surface and produce in the intertidal and lower supratidal zones narrow creeks and shallow depressions meandering perpendicular to the slope. Within a wide tidal flat without local topographic changes in the tidal zones, mat surface structures display a typical shore-parallel zonality. In contrast, in tidal flats with slight changes in topography, the typical shore-parallel zonality appears disturbed mainly along the intertidal and lower supratidal zones. The mat surface structures within each tidal zone show local and lateral transitions but all evolve from an incipient flat or polygonal mat. On the mat scale, microtopographic differences are created by the mats themselves, e.g., in the form of upturned crack margins, bulges and domes. All these are small-scale topographic highs that influence the distribution of microbial activity and mat growth dynamics. In the Abu Dhabi area it is observed that smooth or polygonal mats may grade temporally into mammilate, cinder or pustular and tufted mats along an evolutionary path controlled by preferred growth along bulges and upturned crack margins. A similar temporal evolution appears in the intertidal and supratidal zones in Tunisia where local changes on mat-surface induce a variety of mat-growth struc¬tures on and along upturned crack margins, gas domes and isolated to polygonal bulges and petee ridges. References Kendall C.G.St.C, Skipwith, P.A.d'E. (1968) Recent algal mats of a Persian gulf lagoon. J. Sedim. Res., 38, 1040-1058. Logan B.W. Hoffman P. Gebelein, C.D. (1974) Algal mats, cryptalgal fabrics, and structures, Hamelin Pool, Western Australia. AAPG Mem., 22, 140-194.

Detection of Toxoplasma gondii DNA in horse meat from supermarkets in France and performance evaluation of two serological tests.

PubMed

Aroussi, Abdelkrim; Vignoles, Philippe; Dalmay, François; Wimel, Laurence; Dardé, Marie-Laure; Mercier, Aurélien; Ajzenberg, Daniel

2015-01-01

In France, some cases of severe toxoplasmosis have been linked to the consumption of horse meat that had been imported from the American continent where atypical strains of Toxoplasma gondii are more common than in Europe. Many seroprevalence studies are presented in the literature but risk assessment of T. gondii infection after horse meat consumption is not possible in the absence of validated serological tests and the unknown correlation between detection of antibodies against T. gondii and presence of tissue cysts. We performed magnetic-capture polymerase chain reaction (MC-PCR) to detect T. gondii DNA in 231 horse meat samples purchased in supermarkets in France and evaluated the performance and level of agreement of the modified agglutination test (MAT) and enzyme-linked immunosorbent assay (ELISA) in the meat juices. The serological tests lacked sensitivity, specificity, and agreement between them, and there was no correlation with the presence of T. gondii DNA in horse meat, raising concerns about the reliability of T. gondii seroprevalence data in horses from the literature. T. gondii DNA was detected in 43% of horse meat samples but the absence of strain isolation in mice following inoculation of more than 100 horse meat samples suggests a low distribution of cysts in skeletal muscles and a low risk of T. gondii infection associated with horse meat consumption. However, to avoid any risk of toxoplasmosis, thorough cooking of horse meat is recommended. © A. Aroussi et al., published by EDP Sciences, 2015.

Detection of Toxoplasma gondii DNA in horse meat from supermarkets in France and performance evaluation of two serological tests

PubMed Central

Aroussi, Abdelkrim; Vignoles, Philippe; Dalmay, François; Wimel, Laurence; Dardé, Marie-Laure; Mercier, Aurélien; Ajzenberg, Daniel

2015-01-01

In France, some cases of severe toxoplasmosis have been linked to the consumption of horse meat that had been imported from the American continent where atypical strains of Toxoplasma gondii are more common than in Europe. Many seroprevalence studies are presented in the literature but risk assessment of T. gondii infection after horse meat consumption is not possible in the absence of validated serological tests and the unknown correlation between detection of antibodies against T. gondii and presence of tissue cysts. We performed magnetic-capture polymerase chain reaction (MC-PCR) to detect T. gondii DNA in 231 horse meat samples purchased in supermarkets in France and evaluated the performance and level of agreement of the modified agglutination test (MAT) and enzyme-linked immunosorbent assay (ELISA) in the meat juices. The serological tests lacked sensitivity, specificity, and agreement between them, and there was no correlation with the presence of T. gondii DNA in horse meat, raising concerns about the reliability of T. gondii seroprevalence data in horses from the literature. T. gondii DNA was detected in 43% of horse meat samples but the absence of strain isolation in mice following inoculation of more than 100 horse meat samples suggests a low distribution of cysts in skeletal muscles and a low risk of T. gondii infection associated with horse meat consumption. However, to avoid any risk of toxoplasmosis, thorough cooking of horse meat is recommended. PMID:25809058

rMATS: robust and flexible detection of differential alternative splicing from replicate RNA-Seq data.

PubMed

Shen, Shihao; Park, Juw Won; Lu, Zhi-xiang; Lin, Lan; Henry, Michael D; Wu, Ying Nian; Zhou, Qing; Xing, Yi

2014-12-23

Ultra-deep RNA sequencing (RNA-Seq) has become a powerful approach for genome-wide analysis of pre-mRNA alternative splicing. We previously developed multivariate analysis of transcript splicing (MATS), a statistical method for detecting differential alternative splicing between two RNA-Seq samples. Here we describe a new statistical model and computer program, replicate MATS (rMATS), designed for detection of differential alternative splicing from replicate RNA-Seq data. rMATS uses a hierarchical model to simultaneously account for sampling uncertainty in individual replicates and variability among replicates. In addition to the analysis of unpaired replicates, rMATS also includes a model specifically designed for paired replicates between sample groups. The hypothesis-testing framework of rMATS is flexible and can assess the statistical significance over any user-defined magnitude of splicing change. The performance of rMATS is evaluated by the analysis of simulated and real RNA-Seq data. rMATS outperformed two existing methods for replicate RNA-Seq data in all simulation settings, and RT-PCR yielded a high validation rate (94%) in an RNA-Seq dataset of prostate cancer cell lines. Our data also provide guiding principles for designing RNA-Seq studies of alternative splicing. We demonstrate that it is essential to incorporate biological replicates in the study design. Of note, pooling RNAs or merging RNA-Seq data from multiple replicates is not an effective approach to account for variability, and the result is particularly sensitive to outliers. The rMATS source code is freely available at rnaseq-mats.sourceforge.net/. As the popularity of RNA-Seq continues to grow, we expect rMATS will be useful for studies of alternative splicing in diverse RNA-Seq projects.

Development of electrospun beaded fibers from Thai silk fibroin and gelatin for controlled release application.

PubMed

Somvipart, Siraporn; Kanokpanont, Sorada; Rangkupan, Rattapol; Ratanavaraporn, Juthamas; Damrongsakkul, Siriporn

2013-04-01

Thai silk fibroin and gelatin are attractive biomaterials for tissue engineering and controlled release applications due to their biocompatibility, biodegradability, and bioactive properties. The development of electrospun fiber mats from silk fibroin and gelatin were reported previously. However, burst drug release from such fiber mats remained the problem. In this study, the formation of beads on the fibers aiming to be used for the sustained release of drug was of our interest. The beaded fiber mats were fabricated using electrospinning technique by controlling the solution concentration, weight blending ratio of Thai silk fibroin/gelatin blend, and applied voltage. It was found that the optimal conditions including the solution concentration and the weight blending ratio of Thai silk fibroin/gelatin at 8-10% (w/v) and 70/30, respectively, with the applied voltage at 18 kV provided the fibers with homogeneous formation of beads. Then, the beaded fiber mats obtained were crosslinked by the reaction of carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS). Methylene blue as a model active compound was loaded on the fiber mats. The release test of methylene blue from the beaded fiber mats was carried out in comparison to that of the smooth fiber mats without beads. It was found that the beaded fiber mats could prolong the release of methylene blue, comparing to the smooth fiber mats without beads. This was possibly due to the beaded fiber mats that would absorb and retain higher amount of methylene blue than the fiber mats without beads. Thai silk fibroin/gelatin beaded fiber mats were established as an effective carrier for the controlled release applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Maintaining Two Mating Types: Structure of the Mating Type Locus and Its Role in Heterokaryosis in Podospora anserina

PubMed Central

Grognet, Pierre; Bidard, Frédérique; Kuchly, Claire; Tong, Laetitia Chan Ho; Coppin, Evelyne; Benkhali, Jinane Ait; Couloux, Arnaud; Wincker, Patrick; Debuchy, Robert; Silar, Philippe

2014-01-01

Pseudo-homothallism is a reproductive strategy elected by some fungi producing heterokaryotic sexual spores containing genetically different but sexually compatible nuclei. This lifestyle appears as a compromise between true homothallism (self-fertility with predominant inbreeding) and complete heterothallism (with exclusive outcrossing). However, pseudohomothallic species face the problem of maintaining heterokaryotic mycelia to fully benefit from this lifestyle, as homokaryons are self-sterile. Here, we report on the structure of chromosome 1 in mat+ and mat− isolates of strain S of the pseudohomothallic fungus Podospora anserina. Chromosome 1 contains either one of the mat+ and mat− mating types of P. anserina, which is mostly found in nature as a mat+/mat− heterokaryotic mycelium harboring sexually compatible nuclei. We identified a “mat” region ∼0.8 Mb long, devoid of meiotic recombination and containing the mating-type idiomorphs, which is a candidate to be involved in the maintenance of the heterokaryotic state, since the S mat+ and S mat− strains have different physiology that may enable hybrid-vigor-like phenomena in the heterokaryons. The mat region contains 229 coding sequences. A total of 687 polymorphisms were detected between the S mat+ and S mat− chromosomes. Importantly, the mat region is colinear between both chromosomes, which calls for an original mechanism of recombination inhibition. Microarray analyses revealed that 10% of the P. anserina genes have different transcriptional profiles in S mat+ and S mat−, in line with their different phenotypes. Finally, we show that the heterokaryotic state is faithfully maintained during mycelium growth of P. anserina, yet mat+/mat+ and mat−/mat− heterokaryons are as stable as mat+/mat− ones, evidencing a maintenance of heterokaryosis that does not rely on fitness-enhancing complementation between the S mat+ and S mat− strains. PMID:24558260

Effects of post-fracture non-weight-bearing immobilization on muscle atrophy, intramuscular and intermuscular adipose tissues in the thigh and calf.

PubMed

Yoshiko, Akito; Yamauchi, Koun; Kato, Takayuki; Ishida, Koji; Koike, Teruhiko; Oshida, Yoshiharu; Akima, Hiroshi

2018-06-09

Disuse and/or a non-weight-bearing condition changes muscle composition, with decreased skeletal muscle tissue and increased fat within (intramuscular adipose tissue, IntraMAT) and between (intermuscular adipose tissue, InterMAT) given muscles. Excessive adipose tissue contributes to dysfunctional and metabolically impaired muscle. How these adipose tissues change during orthopedic treatment (e.g., cast immobilization, daily use of crutches) is not well documented. This study aimed to quantify changes in IntraMAT, InterMAT, and thigh and calf muscle tissue during orthopedic treatment. We studied 8 patients with fifth metatarsal bone or fibular fractures. The ankle joint involved underwent plaster casting for approximately 4 weeks, with crutches used during that time. Axial T1-weighted MRI at the mid-thigh and a 30% proximal site at the calf were obtained to measure IntraMAT and InterMAT cross-sectional areas (CSAs) and skeletal muscle tissue CSA before treatment and 4 weeks afterward. Thigh and calf muscle tissue CSAs were significantly decreased from before to after treatment: thigh, 85.8 ± 7.6 to 77.1 ± 7.3 cm 2 ; calf, 53.3 ± 5.5 to 48.9 ± 5.0 cm 2 (p < 0.05). None of the IntraMAT or InterMAT changes was statistically significant. There was a relation between the percentage change of thigh IntraMAT CSA and muscle tissue CSA (r s  = -0.86, p < 0.01). The 4 weeks of treatment primarily induced skeletal muscle atrophy with less of an effect on IntraMAT or InterMAT. There is a risk of increasing IntraMAT relatively by decreasing skeletal muscle tissue size during orthopedic treatment.

B-Scan Based Acoustic Source Reconstruction for Magnetoacoustic Tomography with Magnetic Induction (MAT-MI)

PubMed Central

Mariappan, Leo; Li, Xu; He, Bin

2011-01-01

We present in this study an acoustic source reconstruction method using focused transducer with B mode imaging for magnetoacoustic tomography with magnetic induction (MAT-MI). MAT-MI is an imaging modality proposed for non-invasive conductivity imaging with high spatial resolution. In MAT-MI acoustic sources are generated in a conductive object by placing it in a static and a time-varying magnetic field. The acoustic waves from these sources propagate in all directions and are collected with transducers placed around the object. The collected signal is then usedto reconstruct the acoustic source distribution and to further estimate the electrical conductivity distribution of the object. A flat piston transducer acting as a point receiver has been used in previous MAT-MI systems to collect acoustic signals. In the present study we propose to use B mode scan scheme with a focused transducer that gives a signal gain in its focus region and improves the MAT-MI signal quality. A simulation protocol that can take into account different transducer designs and scan schemes for MAT-MI imaging is developed and used in our evaluation of different MAT-MI system designs. It is shown in our computer simulations that, as compared to the previous approach, the MAT-MI system using B-scan with a focused transducer allows MAT-MI imaging at a closer distance and has improved system sensitivity. In addition, the B scan imaging technique allows reconstruction of the MAT-MI acoustic sources with a discrete number of scanning locations which greatly increases the applicability of the MAT-MI approach especially when a continuous acoustic window is not available in real clinical applications. We have also conducted phantom experiments to evaluate the proposed method and the reconstructed image shows a good agreement with the target phantom. PMID:21097372

Microbial Diversity and Lipid Abundance in Microbial Mats from a Sulfidic, Saline, Warm Spring in Utah, USA

NASA Astrophysics Data System (ADS)

Gong, J.; Edwardson, C.; Mackey, T. J.; Dzaugis, M.; Ibarra, Y.; Course 2012, G.; Frantz, C. M.; Osburn, M. R.; Hirst, M.; Williamson, C.; Hanselmann, K.; Caporaso, J.; Sessions, A. L.; Spear, J. R.

2012-12-01

The microbial diversity of Stinking Springs, a sulfidic, saline, warm spring northeast of the Great Salt Lake was investigated. The measured pH, temperature, salinity, and sulfide concentration along the flow path ranged from 6.64-7.77, 40-28° C, 2.9-2.2%, and 250 μM to negligible, respectively. Five sites were selected along the flow path and within each site microbial mats were dissected into depth profiles based on the color and texture of the mat layers. Genomic DNA was extracted from each layer, and the 16S rRNA gene was amplified and sequenced on the Roche 454 Titanium platform. Fatty acids were also extracted from the mat layers and analyzed by liquid chromatography and mass spectrometry. The mats at Stinking Springs were classified into roughly two morphologies with respect to their spatial distribution: loose, sometimes floating mats proximal to the spring source; and thicker, well-laminated mats distal to the spring source. Loosely-laminated mats were found in turbulent stream flow environments, whereas well-laminated mats were common in less turbulent sheet flows. Phototrophs, sulfur oxidizers, sulfate reducers, methanogens, other bacteria and archaea were identified by 16S rRNA gene sequences. Diatoms, identified by microscopy and lipid analysis were found to increase in abundance with distance from the source. Methanogens were generally more abundant in deeper mat laminae. Photoheterotrophs were found in all mat layers. Microbial diversity increased significantly with depth at most sites. In addition, two distinct microbial streamers were identified and characterized at the two fast flowing sites. These two streamer varieties were dominated by either cyanobacteria or flavobacteria. Overall, our genomic and lipid analysis suggest that the physical and chemical environment is more predictive of the community composition than mat morphology. Site Map

The Oncogene PDRG1 Is an Interaction Target of Methionine Adenosyltransferases

PubMed Central

Garrido, Francisco; Reytor, Edel; Portillo, Francisco; Pajares, María A.

2016-01-01

Methionine adenosyltransferases MAT I and MAT III (encoded by Mat1a) catalyze S-adenosylmethionine synthesis in normal liver. Major hepatic diseases concur with reduced levels of this essential methyl donor, which are primarily due to an expression switch from Mat1a towards Mat2a. Additional changes in the association state and even in subcellular localization of these isoenzymes are also detected. All these alterations result in a reduced content of the moderate (MAT I) and high Vmax (MAT III) isoenzymes, whereas the low Vmax (MAT II) isoenzyme increases and nuclear accumulation of MAT I is observed. These changes derive in a reduced availability of cytoplasmic S-adenosylmethionine, together with an effort to meet its needs in the nucleus of damaged cells, rendering enhanced levels of certain epigenetic modifications. In this context, the putative role of protein-protein interactions in the control of S-adenosylmethionine synthesis has been scarcely studied. Using yeast two hybrid and a rat liver library we identified PDRG1 as an interaction target for MATα1 (catalytic subunit of MAT I and MAT III), further confirmation being obtained by immunoprecipitation and pull-down assays. Nuclear MATα interacts physically and functionally with the PDRG1 oncogene, resulting in reduced DNA methylation levels. Increased Pdrg1 expression is detected in acute liver injury and hepatoma cells, together with decreased Mat1a expression and nuclear accumulation of MATα1. Silencing of Pdrg1 expression in hepatoma cells alters their steady-state expression profile on microarrays, downregulating genes associated with tumor progression according to GO pathway analysis. Altogether, the results unveil the role of PDRG1 in the control of the nuclear methylation status through methionine adenosyltransferase binding and its putative collaboration in the progression of hepatic diseases. PMID:27548429

Molecular Regulation of Sexual Preference Revealed by Genetic Studies of 5-HT in the Brain of Male Mice

PubMed Central

Liu, Yan; Jiang, Yun’ai; Si, Yunxia; Kim, Ji-Young; Chen, Zhou-Feng; Rao, Yi

2014-01-01

To whom should a male directs his mating? While it is a critical social interaction, little is known about molecular and cellular mechanisms controlling mammalian sexual preference. Here we report that the neurotransmitter 5-HT is required for male sexual preference. Male mice lacking central serotonergic neurons lost sexual preference but were not generally defective in olfaction. A role for 5-hydroxytryptamine (5-HT) was demonstrated by the phenotype of mice unable to synthesize 5-HT in the brain when lacking tryptophan hydroxylase 2 (Tph2). 5-hydroxytryptophan (5-HTP) injection rescued the phenotype of adult Tph2 knockout mice within 35 minutes. These results indicate that 5-HT and serotonergic neurons in the adult brain regulate mammalian sexual preference. PMID:21441904

Minor cell-death defects but reduced tumor latency in mice lacking the BH3-only proteins Bad and Bmf.

PubMed

Baumgartner, F; Woess, C; Pedit, V; Tzankov, A; Labi, V; Villunger, A

2013-01-31

Proapoptotic Bcl-2 family members of the Bcl-2 homology (BH)3-only subgroup are critical for the establishment and maintenance of tissue homeostasis and can mediate apoptotic cell death in response to developmental cues or exogenously induced forms of cell stress. On the basis of the biochemical experiments as well as genetic studies in mice, the BH3-only proteins Bad and Bmf have been implicated in different proapoptotic events such as those triggered by glucose- or trophic factor-deprivation, glucocorticoids, or histone deacetylase inhibition, as well as suppression of B-cell lymphomagenesis upon aberrant expression of c-Myc. To address possible redundancies in cell death regulation and tumor suppression, we generated compound mutant mice lacking both genes. Our studies revealed lack of redundancy in most paradigms of lymphocyte apoptosis tested in tissue culture. Only spontaneous cell death of thymocytes kept in low glucose or that of pre-B cells deprived of cytokines was significantly delayed when both genes were lacking. Of note, despite these minor apoptosis defects we observed compromised lymphocyte homeostasis in vivo that affected mainly the B-cell lineage. Long-term follow-up revealed significantly reduced latency to spontaneous tumor formation in aged mice when both genes were lacking. Together our study suggests that Bad and Bmf co-regulate lymphocyte homeostasis and limit spontaneous transformation by mechanisms that may not exclusively be linked to the induction of lymphocyte apoptosis.

Solution blowing of chitosan/PVA hydrogel nanofiber mats.

PubMed

Liu, Ruifang; Xu, Xianlin; Zhuang, Xupin; Cheng, Bowen

2014-01-30

Both nanofiber mats and hydrogel have their own advantages in wound healing. In this study, a novel hydrogel nanofiber mats were fabricated via solution blowing of chitosan and PVA solution, with various content of ethylene glycol diglycidyl ether (EGDE) as cross-linker. SEM observation showed that the fibers were several hundred nanometers in diameter with smooth surface and distributed randomly forming three-dimensional mats. The structure of the chitosan/PVA nanofibers was examined by FTIR and XPS, and the results showed that the cross-linking reaction occurred between EGDE and the hydroxyl groups. The mats could quickly hydrate in an aqueous environment to form hydrogel. Their value of equilibrate water absorption varied from 680 to 459% various content of EGDE. The nanofiber mats showed good bactericidal activity against Escherichia coli. The chitosan/PVA hydrogel nanofiber mats showed the combination advantages of nanofibrous mats and hydrogel dressing, and were suggested as potential application in wound healing. Copyright © 2013 Elsevier Ltd. All rights reserved.

Microbial Species Richness and Metabolic Activities in Hypersaline Microbial Mats: Insight into Biosignature Formation Through Lithification

NASA Astrophysics Data System (ADS)

Baumgartner, Laura K.; Dupraz, Christophe; Buckley, Daniel H.; Spear, John R.; Pace, Norman R.; Visscher, Pieter T.

2009-11-01

Microbial mats in the hypersaline lake of Salt Pan, Eleuthera, Bahamas, display a gradient of lithification along a transect from the center to the shore of the lake. These mats exist under similar geochemical conditions, with light quantity and quality as the sole major environmental difference. Therefore, we hypothesized that the microbial community may be driving the differences in lithification and, by extension, mineral biosignature formation. The lithifying and non-lithifying mat communities were compared (via 16S rRNA gene sequencing, 485 and 464 sequences, respectively) over both temporal and spatial scales. Seven bacterial groups dominated in all the microbial mat libraries: bacteriodetes, alphaproteobacteria, deltaproetobacteria, chloroflexi, spirochaetes, cyanobacteria, and planctomycetes. The mat communities were all significantly different over space, time, and lithification state. Species richness is significantly higher in the non-lithifying mats, potentially due to differences in mat structure and activity. This increased richness may impact lithification and, hence, biosignature production.

The impact of long-term hydrocarbon exposure on the structure, activity, and biogeochemical functioning of microbial mats.

PubMed

Aubé, Johanne; Senin, Pavel; Pringault, Olivier; Bonin, Patricia; Deflandre, Bruno; Bouchez, Olivier; Bru, Noëlle; Biritxinaga-Etchart, Edurne; Klopp, Christophe; Guyoneaud, Rémy; Goñi-Urriza, Marisol

2016-10-15

Photosynthetic microbial mats are metabolically structured systems driven by solar light. They are ubiquitous and can grow in hydrocarbon-polluted sites. Our aim is to determine the impact of chronic hydrocarbon contamination on the structure, activity, and functioning of a microbial mat. We compared it to an uncontaminated mat harboring similar geochemical characteristics. The mats were sampled in spring and fall for 2years. Seasonal variations were observed for the reference mat: sulfur cycle-related bacteria dominated spring samples, while Cyanobacteria dominated in autumn. The contaminated mat showed minor seasonal variation; a progressive increase of Cyanobacteria was noticed, indicating a perturbation of the classical seasonal behavior. Hydrocarbon content was the main factor explaining the differences in the microbial community structure; however, hydrocarbonoclastic bacteria were among rare or transient Operational Taxonomic Units (OTUs) in the contaminated mat. We suggest that in long-term contaminated systems, hydrocarbonoclastic bacteria cannot be considered a sentinel of contamination. Copyright © 2016 Elsevier Ltd. All rights reserved.

Distribution and Composition of Thiotrophic Mats in the Hypoxic Zone of the Black Sea (150–170 m Water Depth, Crimea Margin)

PubMed Central

Jessen, Gerdhard L.; Lichtschlag, Anna; Struck, Ulrich; Boetius, Antje

2016-01-01

At the Black Sea chemocline, oxygen- and sulfide-rich waters meet and form a niche for thiotrophic pelagic bacteria. Here we investigated an area of the Northwestern Black Sea off Crimea close to the shelf break, where the chemocline reaches the seafloor at around 150–170 m water depth, to assess whether thiotrophic bacteria are favored in this zone. Seafloor video transects were carried out with the submersible JAGO covering 20 km2 on the region between 110 and 200 m depth. Around the chemocline we observed irregular seafloor depressions, covered with whitish mats of large filamentous bacteria. These comprised 25–55% of the seafloor, forming a belt of 3 km width around the chemocline. Cores from the mats obtained with JAGO showed higher accumulations of organic matter under the mats compared to mat-free sediments. The mat-forming bacteria were related to Beggiatoa-like large filamentous sulfur bacteria based on 16S rRNA sequences from the mat, and visual characteristics. The microbial community under the mats was significantly different from the surrounding sediments and enriched with taxa affiliated with polymer degrading, fermenting and sulfate reducing microorganisms. Under the mats, higher organic matter accumulation, as well as higher remineralization and radiotracer-based sulfate reduction rates were measured compared to outside the mat. Mat-covered and mat-free sediments showed similar degradability of the bulk organic matter pool, suggesting that the higher sulfide fluxes and subsequent development of the thiotrophic mats in the patches are consequences of the accumulation of organic matter rather than its qualitative composition. Our observations suggest that the key factors for the distribution of thiotrophic mat-forming communities near to the Crimean shelf break are hypoxic conditions that (i) repress grazers, (ii) enhance the accumulation and degradation of labile organic matter by sulfate-reducers, and (iii) favor thiotrophic filamentous bacteria which are adapted to exploit steep gradients in oxygen and sulfide availability; in addition to a specific seafloor topography which may relate to internal waves at the shelf break. PMID:27446049

PAR-2 mediates increased inflammatory cell adhesion and neointima formation following vascular injury in the mouse.

PubMed

Tennant, Gail M; Wadsworth, Roger M; Kennedy, Simon

2008-05-01

Activation of PAR-2 in the vasculature affects vascular tone and adhesion of leukocytes to the endothelium. Since adhesion of leukocytes is increased following vascular injury and is important in determining the extent of neointima formation, we hypothesised that mice lacking PAR-2 may have reduced neointima formation following vascular injury. PAR-2 activating peptides and trypsin induced endothelium-dependent relaxation of mouse carotid artery which was absent in the knockout mouse. Lack of a PAR-2 receptor did not affect lymphocyte adhesion under basal conditions, but reduced the contractile response produced by lymphocytes. Twenty-eight days after denuding injury, vessel contraction to lymphocytes was reduced in both strains while lymphocyte adhesion was significantly greater in PAR-2(+/+) mice compared to the PAR-2 knockout mice. Neointimal area was markedly reduced in the PAR-2 knockout mouse. Our data show that PAR-2 modulates inflammatory cell adhesion when stimulated and in mice lacking the PAR-2 receptor, adhesion to injured vessels is reduced with a consequent reduction in neointima formation.

The protective role of nitric oxide in a neurotoxicant-induced demyelinating model.

PubMed

Arnett, Heather A; Hellendall, Ron P; Matsushima, Glenn K; Suzuki, Kinuko; Laubach, Victor E; Sherman, Paula; Ting, Jenny P-Y

2002-01-01

Demyelination is often associated with acute inflammatory events involving the recruitment-activation of microglia/macrophage, astrocytes, and leukocytes. The ultimate role of inflammatory products in demyelinating disease and in the survival of oligodendrocytes, the myelin forming cells, is unresolved. The current study examines the role of inducible NO synthase (iNOS)-derived NO in a neurotoxicant-induced model of demyelination. NO levels were greatly elevated in the midline corpus callosum during demyelination in genetically intact C57BL/6 mice, and this NO was due solely to the induction of iNOS, as the correlates of NO were not found in mice lacking iNOS. C57BL/6 mice lacking iNOS exhibited more demyelination, but did not display an increased overall cellularity in the corpus callosum, attributable to an unimpeded microglia/macrophage presence. An enhanced course of pathology was noted in mice lacking iNOS. This was associated with a greater depletion of mature oligodendrocytes, most likely due to apoptosis of oligodendrocytes. Microglia and astrocytes did not undergo apoptosis during treatment. Our results suggest a moderately protective role for NO during acute inflammation-association demyelination.

Nicotine anxiogenic and rewarding effects are decreased in mice lacking β-endorphin

PubMed Central

Trigo, José M.; Zimmer, Andreas; Maldonado, Rafael

2009-01-01

The endogenous opioid system plays an important role in the behavioral effects of nicotine. Thus, μ-opioid receptor and the endogenous opioids derived from proenkephalin are involved in the central effects of nicotine. However, the role played by the different endogenous opioid peptides in the acute and chronic effects of nicotine remains to be fully established. Mice lacking β-endorphin were acutely injected with nicotine at different doses to evaluate locomotor, anxiogenic and antinociceptive responses. The rewarding properties of nicotine were evaluated by using the conditioned place-preference paradigm. Mice chronically treated with nicotine were acutely injected with mecamylamine to study the behavioral expression of nicotine withdrawal. Mice lacking β-endorphin exhibited a spontaneous hypoalgesia and hyperlocomotion and a reduction on the anxiogenic and rewarding effects induced by nicotine. Nicotine induced similar antinociception and hypolocomotion in both genotypes and no differences were found in the development of physical dependence. The dissociation between nicotine rewarding properties and physical dependence suggests a differential implication of β-endorphin in these addictive related responses. PMID:19376143

Fatal toxoplasmosis in free-ranging endangered 'Alala from Hawaii

USGS Publications Warehouse

Work, Thierry M.; Massey, J. Gregory; Rideout, Bruce A.; Gardiner, Chris H.; Ledig, David B.; Kwok, O.C.H.; Dubey, J.P.

2000-01-01

The ‘Alala (Corvus hawaiiensis) is the most endangered corvid in the world, and intensive efforts are being made to reintroduce it to its former native range in Hawaii. We diagnosed Toxoplasma gondii infection in five free-ranging ‘Alala. One ‘Alala, recaptured from the wild because it was underweight and depressed, was treated with diclazuril (10 mg/kg) orally for 10 days. Antibodies were measured before and after treatment by the modified agglutination test (MAT) using whole T. gondii tachyzoites fixed in formalin and mercaptoethanol. The MAT titer decreased four-fold from an initial titer of 1:1,600 with remarkable improvement in physical condition. Lesions of toxoplasmosis also were seen in two partially scavenged carcasses and in a third fresh intact carcass. Toxoplasma gondii was confirmed immunohistochemically by using anti-T. gondii specific serum. The organism was also cultured by bioassay in mice from tissues of one of these birds and the brain of a fifth ‘Alala that did not exhibit lesions. The life cycle of the parasite was experimentally completed in cats. This is the first record of toxoplasmosis in ‘Alala, and the parasite appears to pose a significant threat and management challenge to reintroduction programs for ‘Alala in Hawaii.

MatLab Programming for Engineers Having No Formal Programming Knowledge

NASA Technical Reports Server (NTRS)

Shaykhian, Linda H.; Shaykhian, Gholam Ali

2007-01-01

MatLab is one of the most widely used very high level programming languages for Scientific and engineering computations. It is very user-friendly and needs practically no formal programming knowledge. Presented here are MatLab programming aspects and not just the MatLab commands for scientists and engineers who do not have formal programming training and also have no significant time to spare for learning programming to solve their real world problems. Specifically provided are programs for visualization. Also, stated are the current limitations of the MatLab, which possibly can be taken care of by Mathworks Inc. in a future version to make MatLab more versatile.

Polyelectrolyte-Functionalized Nanofiber Mats Control the Collection and Inactivation of Escherichia coli

PubMed Central

Rieger, Katrina A.; Porter, Michael; Schiffman, Jessica D.

2016-01-01

Quantifying the effect that nanofiber mat chemistry and hydrophilicity have on microorganism collection and inactivation is critical in biomedical applications. In this study, the collection and inactivation of Escherichia coli K12 was examined using cellulose nanofiber mats that were surface-functionalized using three polyelectrolytes: poly (acrylic acid) (PAA), chitosan (CS), and polydiallyldimethylammonium chloride (pDADMAC). The polyelectrolyte functionalized nanofiber mats retained the cylindrical morphology and average fiber diameter (~0.84 µm) of the underlying cellulose nanofibers. X-ray photoelectron spectroscopy (XPS) and contact angle measurements confirmed the presence of polycations or polyanions on the surface of the nanofiber mats. Both the control cellulose and pDADMAC-functionalized nanofiber mats exhibited a high collection of E. coli K12, which suggests that mat hydrophilicity may play a larger role than surface charge on cell collection. While the minimum concentration of polycations needed to inhibit E. coli K12 was 800 µg/mL for both CS and pDADMAC, once immobilized, pDADMAC-functionalized nanofiber mats exhibited a higher inactivation of E. coli K12, (~97%). Here, we demonstrate that the collection and inactivation of microorganisms by electrospun cellulose nanofiber mats can be tailored through a facile polyelectrolyte functionalization process. PMID:28773422

Method for production of carbon nanofiber mat or carbon paper

DOEpatents

Naskar, Amit K.

2015-08-04

Method for the preparation of a non-woven mat or paper made of carbon fibers, the method comprising carbonizing a non-woven mat or paper preform (precursor) comprised of a plurality of bonded sulfonated polyolefin fibers to produce said non-woven mat or paper made of carbon fibers. The preforms and resulting non-woven mat or paper made of carbon fiber, as well as articles and devices containing them, and methods for their use, are also described.

Comparative microbial diversity analyses of modern marine thrombolitic mats by barcoded pyrosequencing.

PubMed

Mobberley, Jennifer M; Ortega, Maya C; Foster, Jamie S

2012-01-01

Thrombolites are unlaminated carbonate structures that form as a result of the metabolic interactions of complex microbial mat communities. Thrombolites have a long geological history; however, little is known regarding the microbes associated with modern structures. In this study, we use a barcoded 16S rRNA gene-pyrosequencing approach coupled with morphological analysis to assess the bacterial, cyanobacterial and archaeal diversity associated with actively forming thrombolites found in Highborne Cay, Bahamas. Analyses revealed four distinct microbial mat communities referred to as black, beige, pink and button mats on the surfaces of the thrombolites. At a coarse phylogenetic resolution, the domain bacterial sequence libraries from the four mats were similar, with Proteobacteria and Cyanobacteria being the most abundant. At the finer resolution of the rRNA gene sequences, significant differences in community structure were observed, with dramatically different cyanobacterial communities. Of the four mat types, the button mats contained the highest diversity of Cyanobacteria, and were dominated by two sequence clusters with high similarity to the genus Dichothrix, an organism associated with the deposition of carbonate. Archaeal diversity was low, but varied in all mat types, and the archaeal community was predominately composed of members of the Thaumarchaeota and Euryarchaeota. The morphological and genetic data support the hypothesis that the four mat types are distinctive thrombolitic mat communities. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Increased miR-21-3p in injured brain microvascular endothelial cells following traumatic brain injury aggravates blood-brain barrier damage by promoting cellular apoptosis and inflammation through targeting MAT2B.

PubMed

Ge, Xintong; Li, Wenzhu; Huang, Shan; Yin, Zhenyu; Yang, Mengchen; Han, Zhenying; Han, Zhaoli; Chen, Fanglian; Wang, Haichen; Lei, Ping; Zhang, Jian-Ning

2018-04-26

Our recent papers have reported that increased miR-21-5p in brain following traumatic brain injury (TBI) could improve the neurological outcome through alleviating blood-brain barrier (BBB) damage. miR-21-3p is another mature miRNA derived from pre-miR-21 after Dicer Procession other than miR-21-5p. Its roles in various diseases, such as tumors and myocardial disease aroused great interest for research in recent years. To further explore the function and underlying mechanism of miR-21, especially miR-21-3p in regulating the pathological development of BBB damage after TBI, we designed this research and focused on studying the impact of miR-21-3p on apoptosis and inflammation in brain microvascular endothelial cells (BMVECs), the major cellular component of BBB. We performed controlled cortical impact on mouse brain, and employed the oxygen glucose deprivation/reoxygenation (OGD)-treated bEnd.3 cells injury model. We found that miR-21-3p level in BMVECs from injured cerebral cortex of controlled cortical impact (CCI) mice, and bEnd.3 cells with OGD treatment were both increased after injury. For in-vitro experiments, downregulation on miR-21-3p level by transfecting miR-21-3p antagomir in cultured cells alleviated OGD-induced BBB damage, characterized by decreased BBB leakage and increased expression of tight junction proteins. Besides, miR-21-3p antagomir could suppress cell death by anti-apoptosis, and control inflammatory response by inhibiting the activity of NF-κB signaling. Using luciferase reporter assay and a MAT2B-silenced shRNA vector, we further proved that miR-21-3p exerted above functions through targeting MAT2B. In addition, in-vivo experiments also confirmed that intracerebroventricular infusion of miR-21-3p antagomir could alleviate BBB leakage after TBI. It reduced Evans Blue extravasation and promoted the expression of tight junction proteins, thus contributed to improve the neurological outcome of CCI mice. Taken together, increased miR-21-3p in BMVECs after TBI was bad for restoration of injured BBB. Downregulation on miR-21-3p level in injured brain could be a promising therapeutic strategy for BBB damage after TBI.

Phylogenetic Analysis of Nuclear-Encoded RNA Maturases

PubMed Central

Malik, Sunita; Upadhyaya, KC; Khurana, SM Paul

2017-01-01

Posttranscriptional processes, such as splicing, play a crucial role in gene expression and are prevalent not only in nuclear genes but also in plant mitochondria where splicing of group II introns is catalyzed by a class of proteins termed maturases. In plant mitochondria, there are 22 mitochondrial group II introns. matR, nMAT1, nMAT2, nMAT3, and nMAT4 proteins have been shown to be required for efficient splicing of several group II introns in Arabidopsis thaliana. Nuclear maturases (nMATs) are necessary for splicing of mitochondrial genes, leading to normal oxidative phosphorylation. Sequence analysis through phylogenetic tree (including bootstrapping) revealed high homology with maturase sequences of A thaliana and other plants. This study shows the phylogenetic relationship of nMAT proteins between A thaliana and other nonredundant plant species taken from BLASTP analysis. PMID:28607538

Higher Susceptibility of Mast-Cell-Deficient W/WV Mutant Mice to Brain Thromboembolism and Mortality Caused by Intravenous Injection of India Ink

PubMed Central

Kitamura, Y.; Taguchi, T.; Yokoyama, M.; Inoue, M.; Yamatodani, A.; Asano, H.; Koyama, T.; Kanamaru, A.; Hatanaka, K.; Wershil, B. K.; Galli, S. J.

1986-01-01

(WB × C57BL/6)F1-W/Wv mice possess a genetic defect in multipotential hematopoietic stem cells; the mice are anemic and lack mast cells. The authors injected diluted India ink intravenously into W/WV mice and congenic normal +/+ mice and searched for genetically determined differences in the development of complications of the injection. In both W/WV and +/+ mice, intravenous ink resulted in thrombocytopenia and markedly prolonged bleeding times, as well as prolonged partial thromboplastin and prothrombin times and reduced fibrinogen concentrations. These effects were similar in W/WV and +/+ mice, although the reduction in platelet counts was greater in W/WV mice. In addition, the mortality associated with ink injection was significantly higher in W/WV mice than in congenic +/+ mice. Most W/WV mice which died first exhibited paralysis, and examination under the dissection microscope revealed that ink injection resulted in significantly more cerebral thromboemboli in W/WV mice than in +/+ controls. Bone marrow transplantation from +/+ mice corrected both the mast cell deficiency and the anemia of W/WV mice and protected the W/WV recipients from the adverse consequences of ink injection. By contrast, +/+ mice rendered as anemic as W/WV mice by breeding did not exhibit increased morbidity and mortality after ink injection. (WC × C57BL/6)F1-S1/S1d mice, which are anemic and lack mast cells because of a genetic defect different from that of W/WV mice, also exhibited increased morbidity and mortality after intravenous ink. Finally, mixture of ink with commercial heparin prior to intravenous injection markedly reduced the incidence of cerebral thromboembolism and death in W/WV mice. Taken together, these findings suggest that the increased morbidity and mortality exhibited by W/WV and S1/S1d mice that received injected ink might be related to their mast cell deficiency rather than to their anemia. But measurement of the histamine content of the blood and various tissues of WBB6F1-+/+ mice injected with ink, and examination of their tissues in 1-μ sections, indicated that intravenous ink did not cause substantial mast cell degranulation. As a result, the possibility that mast cells protect +/+ mice from the adverse effects of intravenous ink by a mechanism other than degranulation and release of heparin, or that the differences in the response of W/WV or S1/S1d mice and their +/+ littermates are due to defects other than their lack of mast cells, cannot be excluded. ImagesFigure 2Figure 4 PMID:3513601

Diversity and stratification of archaea in a hypersaline microbial mat.

PubMed

Robertson, Charles E; Spear, John R; Harris, J Kirk; Pace, Norman R

2009-04-01

The Guerrero Negro (GN) hypersaline microbial mats have become one focus for biogeochemical studies of stratified ecosystems. The GN mats are found beneath several of a series of ponds of increasing salinity that make up a solar saltern fed from Pacific Ocean water pumped from the Laguna Ojo de Liebre near GN, Baja California Sur, Mexico. Molecular surveys of the laminated photosynthetic microbial mat below the fourth pond in the series identified an enormous diversity of bacteria in the mat, but archaea have received little attention. To determine the bulk contribution of archaeal phylotypes to the pond 4 study site, we determined the phylogenetic distribution of archaeal rRNA gene sequences in PCR libraries based on nominally universal primers. The ratios of bacterial/archaeal/eukaryotic rRNA genes, 90%/9%/1%, suggest that the archaeal contribution to the metabolic activities of the mat may be significant. To explore the distribution of archaea in the mat, sequences derived using archaeon-specific PCR primers were surveyed in 10 strata of the 6-cm-thick mat. The diversity of archaea overall was substantial albeit less than the diversity observed previously for bacteria. Archaeal diversity, mainly euryarchaeotes, was highest in the uppermost 2 to 3 mm of the mat and decreased rapidly with depth, where crenarchaeotes dominated. Only 3% of the sequences were specifically related to known organisms including methanogens. While some mat archaeal clades corresponded with known chemical gradients, others did not, which is likely explained by heretofore-unrecognized gradients. Some clades did not segregate by depth in the mat, indicating broad metabolic repertoires, undersampling, or both.

Earth's Earliest Ecosystems in the C: The Use of Microbial Mats to Demonstrate General Principles of Scientific Inquiry and Microbial Ecology

NASA Technical Reports Server (NTRS)

Bebout, Brad M.; Bucaria, Robin

2006-01-01

Microbial mats are living examples of the most ancient biological communities on Earth. As Earth's earliest ecosystems, they are centrally important to understanding the history of life on our planet and are useful models for the search for life elsewhere. As relatively compact (but complete) ecosystems, microbial mats are also extremely useful for educational activities. Mats may be used to demonstrate a wide variety of concepts in general and microbial ecology, including the biogeochemical cycling of elements, photosynthesis and respiration, and the origin of the Earth's present oxygen containing atmosphere. Microbial mats can be found in a number of common environments accessible to teachers, and laboratory microbial mats can be constructed using materials purchased from biological supply houses. With funding from NASA's Exobiology program, we have developed curriculum and web-based activities centered on the use of microbial mats as tools for demonstrating general principles in ecology, and the scientific process. Our web site (http://microbes.arc.nasa.gov) includes reference materials, lesson plans, and a "Web Lab", featuring living mats maintained in a mini-aquarium. The site also provides information as to how research on microbial mats supports NASA's goals, and various NASA missions. A photo gallery contains images of mats, microscopic views of the organisms that form them, and our own research activities. An animated educational video on the web site uses computer graphic and video microscopy to take students on a journey into a microbial mat. These activities are targeted to a middle school audience and are aligned with the National Science Standards.

Cyanobacterial construction of hot spring siliceous stromatolites in Yellowstone National Park.

PubMed

Pepe-Ranney, Charles; Berelson, William M; Corsetti, Frank A; Treants, Merika; Spear, John R

2012-05-01

Living stromatolites growing in a hot spring in Yellowstone National Park are composed of silica-encrusted cyanobacterial mats. Two cyanobacterial mat types grow on the stromatolite surfaces and are preserved as two distinct lithofacies. One mat is present when the stromatolites are submerged or at the water-atmosphere interface and the other when stromatolites protrude from the hot spring. The lithofacies created by the encrustation of submerged mats constitutes the bulk of the stromatolites, is comprised of silica-encrusted filaments, and is distinctly laminated. To better understand the cyanobacterial membership and community structure differences between the mats, we collected mat samples from each type. Molecular methods revealed that submerged mat cyanobacteria were predominantly one novel phylotype while the exposed mats were predominantly heterocystous phylotypes (Chlorogloeopsis HTF and Fischerella). The cyanobacterium dominating the submerged mat type does not belong in any of the subphylum groups of cyanobacteria recognized by the Ribosomal Database Project and has also been found in association with travertine stromatolites in a Southwest Japan hot spring. Cyanobacterial membership profiles indicate that the heterocystous phylotypes are 'rare biosphere' members of the submerged mats. The heterocystous phylotypes likely emerge when the water level of the hot spring drops. Environmental pressures tied to water level such as sulfide exposure and possibly oxygen tension may inhibit the heterocystous types in submerged mats. These living stromatolites are finely laminated and therefore, in texture, may better represent similarly laminated ancient forms compared with more coarsely laminated living marine examples. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Genetic depletion of brain 5HT reveals a common molecular pathway mediating compulsivity and impulsivity.

PubMed

Angoa-Pérez, Mariana; Kane, Michael J; Briggs, Denise I; Sykes, Catherine E; Shah, Mrudang M; Francescutti, Dina M; Rosenberg, David R; Thomas, David M; Kuhn, Donald M

2012-06-01

Neuropsychiatric disorders characterized by behavioral disinhibition, including disorders of compulsivity (e.g. obsessive-compulsive disorder; OCD) and impulse-control (e.g. impulsive aggression), are severe, highly prevalent and chronically disabling. Treatment options for these diseases are extremely limited. The pathophysiological bases of disorders of behavioral disinhibition are poorly understood but it has been suggested that serotonin dysfunction may play a role. Mice lacking the gene encoding brain tryptophan hydroxylase 2 (Tph2-/-), the initial and rate-limiting enzyme in the synthesis of serotonin, were tested in numerous behavioral assays that are well known for their utility in modeling human neuropsychiatric diseases. Mice lacking Tph2 (and brain 5HT) show intense compulsive and impulsive behaviors to include extreme aggression. The impulsivity is motor in form and not cognitive because Tph2-/- mice show normal acquisition and reversal learning on a spatial learning task. Restoration of 5HT levels by treatment of Tph2-/- mice with its immediate precursor 5-hydroxytryptophan attenuated compulsive and impulsive-aggressive behaviors. Surprisingly, in Tph2-/- mice, the lack of 5HT was not associated with anxiety-like behaviors. The results indicate that 5HT mediates behavioral disinhibition in the mammalian brain independent of anxiogenesis. © 2012 The Authors. Journal of Neurochemistry © 2012 International Society for Neurochemistry.

Quantitative impact of thymic selection on Foxp3+ and Foxp3- subsets of self-peptide/MHC class II-specific CD4+ T cells.

PubMed

Moon, James J; Dash, Pradyot; Oguin, Thomas H; McClaren, Jennifer L; Chu, H Hamlet; Thomas, Paul G; Jenkins, Marc K

2011-08-30

It is currently thought that T cells with specificity for self-peptide/MHC (pMHC) ligands are deleted during thymic development, thereby preventing autoimmunity. In the case of CD4(+) T cells, what is unclear is the extent to which self-peptide/MHC class II (pMHCII)-specific T cells are deleted or become Foxp3(+) regulatory T cells. We addressed this issue by characterizing a natural polyclonal pMHCII-specific CD4(+) T-cell population in mice that either lacked or expressed the relevant antigen in a ubiquitous pattern. Mice expressing the antigen contained one-third the number of pMHCII-specific T cells as mice lacking the antigen, and the remaining cells exhibited low TCR avidity. In mice lacking the antigen, the pMHCII-specific T-cell population was dominated by phenotypically naive Foxp3(-) cells, but also contained a subset of Foxp3(+) regulatory cells. Both Foxp3(-) and Foxp3(+) pMHCII-specific T-cell numbers were reduced in mice expressing the antigen, but the Foxp3(+) subset was more resistant to changes in number and TCR repertoire. Therefore, thymic selection of self-pMHCII-specific CD4(+) T cells results in incomplete deletion within the normal polyclonal repertoire, especially among regulatory T cells.

Colonization of oak wilt fungal mats by Ophiostoma piceae during spring in Minnesota

Treesearch

Jennifer Juzwik; Jason M. Meyer

1997-01-01

The colonization of Ceratocystis fagacearum fungal mats of different ages by Ophiostoma piceae on Quercus spp. was determined in three east-central Minnesota locations during the spring of 1995. The extent of the mat area colonized by O. piceae generally increased with mat age. Subsamples per...

Pathogenesis of persistent hyperplastic primary vitreous in mice lacking the arf tumor suppressor gene.

PubMed

Martin, Amy C; Thornton, J Derek; Liu, Jiewiu; Wang, XiaoFei; Zuo, Jian; Jablonski, Monica M; Chaum, Edward; Zindy, Frederique; Skapek, Stephen X

2004-10-01

Persistent hyperplastic primary vitreous (PHPV) is an idiopathic developmental eye disease associated with failed involution of the hyaloid vasculature. The present work addressed the pathogenesis of PHPV in a mouse model that replicates many aspects of the human disease. Ophthalmoscopic and histologic analyses documented pathologic processes in eyes of mice lacking the Arf gene compared with Ink4a-deficient and wild-type control animals. Immunohistochemical staining, in situ hybridization, and RT-PCR demonstrated the expression of relevant gene products. Arf gene expression was determined by in situ hybridization using wholemounts of wild-type mouse eyes and by immunofluorescence staining for green fluorescent protein (GFP) in Arf(+/GFP) heterozygous knock-in mouse eyes. Abnormalities in Arf(-/-) mice mimicked those found in patients with severe PHPV. The mice had microphthalmia; fibrovascular, retrolental tissue containing retinal pigment epithelial cells and remnants of the hyaloid vascular system; posterior lens capsule destruction with lens degeneration and opacity; and severe retinal dysplasia and detachment. Eyes of mice lacking the overlapping Ink4a gene were normal. Arf was selectively expressed in perivascular cells within the vitreous of the postnatal eye. Cells composing the retrolental mass in Arf(-/-) mice expressed the Arf promoter. The remnant hyaloid vessels expressed Flk-1. Its ligand, vascular endothelial growth factor (Vegf), was expressed in the retrolental tissue and the adjacent dysplastic neuroretina. Arf(-/-) mice have features that accurately mimic severe PHPV. In the HVS, Arf expression in perivascular cells may block their accumulation or repress Vegf expression to promote HVS involution and prevent PHPV.

Pathogenesis of Persistent Hyperplastic Primary Vitreous in Mice Lacking the Arf Tumor Suppressor Gene

PubMed Central

Martin, Amy C.; Thornton, J. Derek; Liu, Jiewiu; Wang, XiaoFei; Zuo, Jian; Jablonski, Monica M.; Chaum, Edward; Zindy, Frederique; Skapek, Stephen X.

2006-01-01

Purpose Persistent hyperplastic primary vitreous (PHPV) is an idiopathic developmental eye disease associated with failed involution of the hyaloid vasculature. The present work addressed the pathogenesis of PHPV in a mouse model that replicates many aspects of the human disease. Methods Ophthalmoscopic and histologic analyses documented pathologic processes in eyes of mice lacking the Arf gene compared with Ink4a-deficient and wild-type control animals. Immunohistochemical staining, in situ hybridization, and RT-PCR demonstrated the expression of relevant gene products. Arf gene expression was determined by in situ hybridization using wholemounts of wild-type mouse eyes and by immunofluorescence staining for green fluores-cent protein (GFP) in Arf+/GFP heterozygous knock-in mouse eyes. Results Abnormalities in Arf−/− mice mimicked those found in patients with severe PHPV. The mice had microphthalmia; fibrovascular, retrolental tissue containing retinal pigment epithelial cells and remnants of the hyaloid vascular system; posterior lens capsule destruction with lens degeneration and opacity; and severe retinal dysplasia and detachment. Eyes of mice lacking the overlapping Ink4a gene were normal. Arf was selectively expressed in perivascular cells within the vitreous of the postnatal eye. Cells composing the retrolental mass in Arf−/− mice expressed the Arf promoter. The remnant hyaloid vessels expressed Flk-1. Its ligand, vascular endothelial growth factor (Vegf), was expressed in the retrolental tissue and the adjacent dysplastic neuroretina. Conclusions Arf−/− mice have features that accurately mimic severe PHPV. In the HVS, Arf expression in perivascular cells may block their accumulation or repress Vegf expression to promote HVS involution and prevent PHPV. PMID:15452040

Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS) Users' Workshop Presentations

NASA Technical Reports Server (NTRS)

Litt, Jonathan S. (Compiler)

2018-01-01

NASA Glenn Research Center hosted a Users' Workshop on the Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS) on August 21, 2017. The objective of this workshop was to update the user community on the latest features of T-MATS, and to provide a forum to present work performed using T-MATS. Presentations highlighted creative applications and the development of new features and libraries, and emphasized the flexibility and simulation power of T-MATS.

Effects of tacky mat contamination on bond degradation for Chemlok/liner and NBR/liner bonds

NASA Technical Reports Server (NTRS)

Padilla, A. M.

1989-01-01

Tacky mats are placed by the rubber lay-up areas for the solid rocket motor segments. These mats dust off the shoes prior to entering the platform where the lay-up work is performed. The possibility exists that a tacky mat could be touched with gloved hands prior to handling the uncured nitride butadiene rubber (NBR). Tests were run to determine if NBR were accidentally touched would there be any degradation of the liner/NBR bond. The tacky mats were judged solely on the basis of bond degradation caused by either direct or indirect contamination. Test results all indicate that there was no notable NBR/Chemlok or liner/NBR bond degradation on samples that came into contact with the tacky mat material. Testing procedures are described. The tacky mat adhesive composition does not contain fluorocarbons or release agents that would affect bonding.

Comparative functional ultrastructure of two hypersaline submerged cyanobacterial mats - Guerrero Negro, Baja California Sur, Mexico, and Solar Lake, Sinai, Egypt

NASA Technical Reports Server (NTRS)

D'Amelio, Elisa D'antoni; Des Marais, David J.; Cohen, Jehuda

1989-01-01

The ultrastructure of the submerged microbial mat from the Solar Lake (SL), Egypt, was compared to that of samples from the Guerrero Negro (GN), Mexico, salt pans. The locations and distributions of the main organisms were determined light microscopy, and the corresponding ultrathin sections were examined under TEM; chemical microprofile analyses were carried out on the day of sampling for microscopic studies. Both communities were found to be dominated by Microleus chthonoplastes, although several morphological species found in the GN mat were absent from the SL mat, including the Tropica nigra and the 'big' Microleus chthonoplastes component. The chemical microprofiles of oxygen, sulfide, pH, and the oxygenic photosynthesis in the two mats were virtually identical. In both mats, the photic zone was restricted to the upper 800 microns of the mat, and oxygenic photosynthesis was detected down to 600 microns.

Micropatterned stretchable circuit and strain sensor fabricated by lithography on an electrospun nanofiber mat.

PubMed

Park, Minwoo; Im, Jungkyun; Park, Jongjin; Jeong, Unyong

2013-09-11

This paper describes a novel approach for composite nanofiber mats and its application to fabricate a strain sensor. Electrospun poly(4-vinylpyridine) (P4VP) nanofiber mats are micropatterned by a lithographic approach that includes selective oxidation of the nanofibers and removal of unreacted fibers. The P4VP/HAuCl4 complex is converted to P4VP/Au composites by chemical reduction. We investigate the electrical resistivity of the composite mats according to the number of complexation-and-reduction cycles, the thickness of the fiber mats, and the annealing temperatures which control the percolation of the Au nanoparticles in the fiber mats. Nozzle printing of a polymeric solution on the patterned nanofiber mats simply produces an array of strain-sensitive and strain-invariant units. The patterns demonstrate high strain-sensing performance without any mechanical and electrical failure over 200 bending cycles in the strain range of ε<0.17.

49 CFR 393.122 - What are the rules for securing paper rolls?

Code of Federal Regulations, 2014 CFR

2014-10-01

... prevented by filling the void, blocking, bracing, tiedowns or friction mats. The paper rolls may also be... vehicle, exceeds the diameter of the paper rolls, rearward movement must be prevented by friction mats... less than 1.75 times its diameter, and it is restrained against forward movement by friction mat(s...

Users guide for ERB 7 MAT (including the first year quality control)

NASA Technical Reports Server (NTRS)

Groveman, B.

1984-01-01

In the first section of this report background information for the use of the ERB-7 Master Archival Tapes (MAT) is provided. The second section gives details regarding the scientific validity and quality of the MAT. The MAT data analyzed covers the period from November 16, 1978 to October 31, 1979.

Fabricating poly(1,8-octanediol citrate) elastomer based fibrous mats via electrospinning for soft tissue engineering scaffold.

PubMed

Zhu, Lei; Zhang, Yuanzheng; Ji, Yali

2017-06-01

Poly(1,8-octanediol citrate) (POC) is a recently developed biodegradable crosslinked elastomer that possesses good cytocompatibility and matchable mechanical properties to soft tissues. However, the thermosetting characteristic reveals a big challenge to manufacture its porous scaffold. Herein, POC elastomer was electrospun into fiber mat using poly(L-lactic acid) (PLLA) as a spinnable carrier. The obtained POC/PLLA fiber mats were characterized by scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), uniaxial tensile test, static-water-contact-angle, thermal analysis, in vitro degradation and biocompatibility test. It was found that the fibrous structure could be formed so long as the POC pre-polymer's content was no more than 50 wt%. The presence of elastic POC component not only strengthened the fiber mats but also toughened the fiber mats. The hydrophilicity of 50/50 fiber mat significantly improved. In vitro degradation rate of POC based fiber mats was much faster than that of pure PLLA. Cyto- and histo-compatibility tests confirmed that the POC/PLLA fiber mats had good biocompatibility for potential applications in soft tissue engineering.

Chemotherapy inhibits skeletal muscle ubiquitin-proteasome-dependent proteolysis.

PubMed

Tilignac, Thomas; Temparis, Sandrine; Combaret, Lydie; Taillandier, Daniel; Pouch, Marie-Noëlle; Cervek, Matjaz; Cardenas, Diana M; Le Bricon, Thierry; Debiton, Eric; Samuels, Susan E; Madelmont, Jean-Claude; Attaix, Didier

2002-05-15

Chemotherapy has cachectic effects, but it is unknown whether cytostatic agents alter skeletal muscle proteolysis. We hypothesized that chemotherapy-induced alterations in protein synthesis should result in the increased incidence of abnormal proteins, which in turn should stimulate ubiquitin-proteasome-dependent proteolysis. The effects of the nitrosourea cystemustine were investigated in skeletal muscles from both healthy and colon 26 adenocarcinoma-bearing mice, an appropriate model for testing the impact of cytostatic agents. Muscle wasting was seen in both groups of mice 4 days after a single cystemustine injection, and the drug further increased the loss of muscle proteins already apparent in tumor-bearing animals. Cystemustine cured the tumor-bearing mice with 100% efficacy. Surprisingly, within 11 days of treatment, rates of muscle proteolysis progressively decreased below basal levels observed in healthy control mice and contributed to the cessation of muscle wasting. Proteasome-dependent proteolysis was inhibited by mechanisms that include reduced mRNA levels for 20S and 26S proteasome subunits, decreased protein levels of 20S proteasome subunits and the S14 non-ATPase subunit of the 26S proteasome, and impaired chymotrypsin- and trypsin-like activities of the enzyme. A combination of cisplatin and ifosfamide, two drugs that are widely used in the treatment of cancer patients, also depressed the expression of proteasomal subunits in muscles from rats bearing the MatB adenocarcinoma below basal levels. Thus, a down-regulation of ubiquitin-proteasome-dependent proteolysis is observed with various cytostatic agents and contributes to reverse the chemotherapy-induced muscle wasting.

Influence of layer-by-layer assembled electrospun poly (L-lactic acid) nanofiber mats on the bioactivity of endothelial cells

NASA Astrophysics Data System (ADS)

Wu, Keke; Zhang, Xiazhi; Yang, Wufeng; Liu, Xiaoyan; Jiao, Yanpeng; Zhou, Changren

2016-12-01

Electrospun poly(L-lactic acid) (PLLA) nanofiber mats were successfully modified by deposition of multilayers with chitosan (CS), heparin (Hep) and graphene oxide (GO) through electrostatic layer-by-layer (LBL) self-assembly method. In this study, the surface properties of PLLA nanofiber mats before and after modification were investigated via scanning electron microscope (SEM), atomic force microscopy (AFM), attenuated total reflectance fourier transformation infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and water contact angle measurement. In addition, the cytocompatibility of the modified PLLA nanofiber mats were investigated by testing endothelial cells compatibility, including cell attachment, cell proliferation and cell cycle. The results revealed that the surfaces of modified PLLA nanofiber mats become much rougher, stifiness and the hydrophilicity of the LBL modified PLLA nanofiber mats were improved compared to original PLLA one. Moreover, the modified PLLA nanofiber mats had promoted the endothelial cells viability attachment significantly. Besides, we studied the PLLA nanofiber mats on the expression of necrosis factor (TNF-α), interleukine-1β (IL-1β), monocyte chemoattractant protein-1 (MCP-1) and vascular cell adhesion molecule-1 (VCAM-1) in endothelial cells. The results showed that modified PLLA nanofiber mats had inhibited the inflammatory response to some extent.

Niche differentiation of bacterial communities at a millimeter scale in Shark Bay microbial mats

NASA Astrophysics Data System (ADS)

Wong, Hon Lun; Smith, Daniela-Lee; Visscher, Pieter T.; Burns, Brendan P.

2015-10-01

Modern microbial mats can provide key insights into early Earth ecosystems, and Shark Bay, Australia, holds one of the best examples of these systems. Identifying the spatial distribution of microorganisms with mat depth facilitates a greater understanding of specific niches and potentially novel microbial interactions. High throughput sequencing coupled with elemental analyses and biogeochemical measurements of two distinct mat types (smooth and pustular) at a millimeter scale were undertaken in the present study. A total of 8,263,982 16S rRNA gene sequences were obtained, which were affiliated to 58 bacterial and candidate phyla. The surface of both mats were dominated by Cyanobacteria, accompanied with known or putative members of Alphaproteobacteria and Bacteroidetes. The deeper anoxic layers of smooth mats were dominated by Chloroflexi, while Alphaproteobacteria dominated the lower layers of pustular mats. In situ microelectrode measurements revealed smooth mats have a steeper profile of O2 and H2S concentrations, as well as higher oxygen production, consumption, and sulfate reduction rates. Specific elements (Mo, Mg, Mn, Fe, V, P) could be correlated with specific mat types and putative phylogenetic groups. Models are proposed for these systems suggesting putative surface anoxic niches, differential nitrogen fixing niches, and those coupled with methane metabolism.

Magnetoacoustic tomography with magnetic induction (MAT-MI)

NASA Astrophysics Data System (ADS)

Xu, Yuan; He, Bin

2005-11-01

We report our theoretical and experimental investigations on a new imaging modality, magnetoacoustic tomography with magnetic induction (MAT-MI). In MAT-MI, the sample is located in a static magnetic field and a time-varying (µs) magnetic field. The time-varying magnetic field induces an eddy current in the sample. Consequently, the sample will emit ultrasonic waves by the Lorentz force. The ultrasonic signals are collected around the object to reconstruct images related to the electrical impedance distribution in the sample. MAT-MI combines the good contrast of electrical impedance tomography with the good spatial resolution of sonography. MAT-MI has two unique features due to the solenoid nature of the induced electrical field. Firstly, MAT-MI could provide an explicit or simple quantitative reconstruction algorithm for the electrical impedance distribution. Secondly, it promises to eliminate the shielding effects of other imaging modalities in which the current is applied directly with electrodes. In the theoretical part, we provide formulae for both the forward and inverse problems of MAT-MI and estimate the signal amplitude in biological tissues. In the experimental part, the experimental setup and methods are introduced and the signals and the image of a metal object by means of MAT-MI are presented. The promising pilot experimental results suggest the feasibility of the proposed MAT-MI approach.

Interaction of gelatin with polyenes modulates antifungal activity and biocompatibility of electrospun fiber mats

PubMed Central

Lakshminarayanan, Rajamani; Sridhar, Radhakrishnan; Loh, Xian Jun; Nandhakumar, Muruganantham; Barathi, Veluchamy Amutha; Kalaipriya, Madhaiyan; Kwan, Jia Lin; Liu, Shou Ping; Beuerman, Roger Wilmer; Ramakrishna, Seeram

2014-01-01

Topical application of antifungals does not have predictable or well-controlled release characteristics and requires reapplication to achieve therapeutic local concentration in a reasonable time period. In this article, the efficacy of five different US Food and Drug Administration-approved antifungal-loaded (amphotericin B, natamycin, terbinafine, fluconazole, and itraconazole) electrospun gelatin fiber mats were compared. Morphological studies show that incorporation of polyenes resulted in a two-fold increase in fiber diameter and the mats inhibit the growth of yeasts and filamentous fungal pathogens. Terbinafine-loaded mats were effective against three filamentous fungal species. Among the two azole antifungals compared, the itraconazole-loaded mat was potent against Aspergillus strains. However, activity loss was observed for fluconazole-loaded mats against all of the test organisms. The polyene-loaded mats displayed rapid candidacidal activities as well. Biophysical and rheological measurements indicate strong interactions between polyene antifungals and gelatin matrix. As a result, the polyenes stabilized the triple helical conformation of gelatin and the presence of gelatin decreased the hemolytic activity of polyenes. The polyene-loaded fiber mats were noncytotoxic to primary human corneal and sclera fibroblasts. The reduction of toxicity with complete retention of activity of the polyene antifungal-loaded gelatin fiber mats can provide new opportunities in the management of superficial skin infections. PMID:24920895

The green alga, Cladophora, promotes Escherichia coli growth and contamination of recreational waters in Lake Michigan.

PubMed

Vanden Heuvel, Amy; McDermott, Colleen; Pillsbury, Robert; Sandrin, Todd; Kinzelman, Julie; Ferguson, John; Sadowsky, Michael; Byappanahalli, Muruleedhara; Whitman, Richard; Kleinheinz, Gregory T

2010-01-01

A linkage between Cladophora mats and exceedances of recreational water quality criteria has been suggested, but not directly studied. This study investigates the spatial and temporal association between Escherichia coli concentrations within and near Cladophora mats at two northwestern Lake Michigan beaches in Door County, Wisconsin. Escherichia coli concentrations in water underlying mats were significantly greater than surrounding water (p < 0.001). Below mat E. coli increased as the stranded mats persisted at the beach swash zone. Water adjacent to Cladophora mats had lower E. coli concentrations, but surpassed EPA swimming criteria the majority of sampling days. A significant positive association was found between E. coli concentrations attached to Cladophora and in underlying water (p < 0.001). The attached E. coli likely acted as a reservoir for populating water underlying the mat. Fecal bacterial pathogens, however, could not be detected by microbiological culture methods either attached to mat biomass or in underlying water. Removal of Cladophora mats from beach areas may improve aesthetic and microbial water quality at affected beaches. These associations and potential natural growth of E. coli in bathing waters call into question the efficacy of using E. coli as a recreational water quality indicator of fecal contaminations.

MyD88 Deficiency Markedly Worsens Tissue Inflammation and Bacterial Clearance in Mice Infected with Treponema pallidum, the Agent of Syphilis

PubMed Central

Silver, Adam C.; Dunne, Dana W.; Zeiss, Caroline J.; Bockenstedt, Linda K.; Radolf, Justin D.; Salazar, Juan C.; Fikrig, Erol

2013-01-01

Research on syphilis, a sexually transmitted infection caused by the non-cultivatable spirochete Treponema pallidum, has been hampered by the lack of an inbred animal model. We hypothesized that Toll-like receptor (TLR)-dependent responses are essential for clearance of T. pallidum and, consequently, compared infection in wild-type (WT) mice and animals lacking MyD88, the adaptor molecule required for signaling by most TLRs. MyD88-deficient mice had significantly higher pathogen burdens and more extensive inflammation than control animals. Whereas tissue infiltrates in WT mice consisted of mixed mononuclear and plasma cells, infiltrates in MyD88-deficient animals were predominantly neutrophilic. Although both WT and MyD88-deficient mice produced antibodies that promoted uptake of treponemes by WT macrophages, MyD88-deficient macrophages were deficient in opsonophagocytosis of treponemes. Our results demonstrate that TLR-mediated responses are major contributors to the resistance of mice to syphilitic disease and that MyD88 signaling and FcR-mediated opsonophagocytosis are linked to the macrophage-mediated clearance of treponemes. PMID:23940747

Deficiency of prolyl oligopeptidase in mice disturbs synaptic plasticity and reduces anxiety-like behaviour, body weight, and brain volume.

PubMed

Höfling, Corinna; Kulesskaya, Natalia; Jaako, Külli; Peltonen, Iida; Männistö, Pekka T; Nurmi, Antti; Vartiainen, Nina; Morawski, Markus; Zharkovsky, Alexander; Võikar, Vootele; Roßner, Steffen; García-Horsman, J Arturo

2016-06-01

Prolyl oligopeptidase (PREP) has been implicated in neurodegeneration and neuroinflammation and has been considered a drug target to enhance memory in dementia. However, the true physiological role of PREP is not yet understood. In this paper, we report the phenotyping of a mouse line where the PREP gene has been knocked out. This work indicates that the lack of PREP in mice causes reduced anxiety but also hyperactivity. The cortical volumes of PREP knockout mice were smaller than those of wild type littermates. Additionally, we found increased expression of diazepam binding inhibitor protein in the cortex and of the somatostatin receptor-2 in the hippocampus of PREP knockout mice. Furthermore, immunohistochemistry and tail suspension test revealed lack of response of PREP knockout mice to lipopolysaccharide insult. Further analysis revealed significantly increased levels of polysialylated-neural cell adhesion molecule in PREP deficient mice. These findings might be explained as possible alteration in brain plasticity caused by PREP deficiency, which in turn affect behaviour and brain development. Copyright © 2016 Elsevier B.V. and ECNP. All rights reserved.

Impaired locomotor activity and exploratory behavior in mice lacking histamine H1 receptors

PubMed Central

Inoue, Isao; Yanai, Kazuhiko; Kitamura, Daisuke; Taniuchi, Ichiro; Kobayashi, Takashi; Niimura, Kaku; Watanabe, Takehiko; Watanabe, Takeshi

1996-01-01

From pharmacological studies using histamine antagonists and agonists, it has been demonstrated that histamine modulates many physiological functions of the hypothalamus, such as arousal state, locomotor activity, feeding, and drinking. Three kinds of receptors (H1, H2, and H3) mediate these actions. To define the contribution of the histamine H1 receptors (H1R) to behavior, mutant mice lacking the H1R were generated by homologous recombination. In brains of homozygous mutant mice, no specific binding of [3H]pyrilamine was seen. [3H]Doxepin has two saturable binding sites with higher and lower affinities in brains of wild-type mice, but H1R-deficient mice showed only the weak labeling of [3H]doxepin that corresponds to lower-affinity binding sites. Mutant mice develop normally, but absence of H1R significantly increased the ratio of ambulation during the light period to the total ambulation for 24 hr in an accustomed environment. In addition, mutant mice significantly reduced exploratory behavior of ambulation and rearings in a new environment. These results indicate that through H1R, histamine is involved in circadian rhythm of locomotor activity and exploratory behavior as a neurotransmitter. PMID:8917588

Mutations in monoamine oxidase (MAO) genes in mice lead to hypersensitivity to serotonin-enhancing drugs: implications for drug side effects in humans.

PubMed

Fox, M A; Panessiti, M G; Moya, P R; Tolliver, T J; Chen, K; Shih, J C; Murphy, D L

2013-12-01

A possible side effect of serotonin-enhancing drugs is the serotonin syndrome, which can be lethal. Here we examined possible hypersensitivity to two such drugs, the serotonin precursor 5-hydroxy-L-tryptophan (5-HTP) and the atypical opioid tramadol, in mice lacking the genes for both monoamine oxidase A (MAOA) and MAOB. MAOA/B-knockout (KO) mice displayed baseline serotonin syndrome behaviors, and these behavioral responses were highly exaggerated following 5-HTP or tramadol versus baseline and wild-type (WT) littermates. Compared with MAOA/B-WT mice, baseline tissue serotonin levels were increased ∼2.6-3.9-fold in MAOA/B-KO mice. Following 5-HTP, serotonin levels were further increased ∼4.5-6.2-fold in MAOA/B-KO mice. These exaggerated responses are in line with the exaggerated responses following serotonin-enhancing drugs that we previously observed in mice lacking the serotonin transporter (SERT). These findings provide a second genetic mouse model suggestive of possible human vulnerability to the serotonin syndrome in individuals with lesser-expressing MAO or SERT polymorphisms that confer serotonergic system changes.

Mutations in monoamine oxidase (MAO) genes in mice lead to hypersensitivity to serotonin-enhancing drugs: implications for drug side effects in humans

PubMed Central

Fox, MA; Panessiti, MG; Moya, PR; Tolliver, TJ; Chen, K; Shih, JC; Murphy, DL

2012-01-01

A possible side effect of serotonin-enhancing drugs is the serotonin syndrome, which can be lethal. Here we examined possible hypersensitivity to two such drugs, the serotonin precursor 5-hydroxy-L-tryptophan (5-HTP) and the atypical opioid tramadol, in mice lacking the genes for both monoamine oxidase A (MAOA) and MAOB. MAOA/B-knockout (KO) mice displayed baseline serotonin syndrome behaviors, and these behavioral responses were highly exaggerated following 5-HTP or tramadol versus baseline and wild-type (WT) littermates. Compared with MAOA/B-WT mice, baseline tissue serotonin levels were increased ~2.6–3.9-fold in MAOA/B-KO mice. Following 5-HTP, serotonin levels were further increased ~4.5–6.2-fold in MAOA/B-KO mice. These exaggerated responses are in line with the exaggerated responses following serotonin-enhancing drugs that we previously observed in mice lacking the serotonin transporter (SERT). These findings provide a second genetic mouse model suggestive of possible human vulnerability to the serotonin syndrome in individuals with lesser-expressing MAO or SERT polymorphisms that confer serotonergic system changes. PMID:22964922

Long Term Manipulations of Intact Microbial Mat Communities in a Greenhouse Collaboratory: Simulating Earth's Present and Past Field Environments

NASA Technical Reports Server (NTRS)

Bebout, Brad; DesMarais, David J.; Discipulo, Mykell; Embaye, Tsegereda; Garcia-Pichel, Ferran; Hogan, Mary; Jahnke, Linda L.; Keller, Richard M.; Miller, Scott R.; Prufert-Bebout, Leslie E.;

Long-Term Manipulations of Intact Microbial Mat Communities in a Greenhouse Collaboratory: Simulating Earth's Present and Past Field Environments

NASA Astrophysics Data System (ADS)

Bebout, Brad M.; Carpenter, Steven P.; Des Marais, David J.; Discipulo, Mykell; Embaye, Tsegereda; Garcia-Pichel, Ferran; Hoehler, Tori M.; Hogan, Mary; Jahnke, Linda L.; Keller, Richard M.; Miller, Scott R.; Prufert-Bebout, Leslie E.; Raleigh, Chris; Rothrock, Michael; Turk, Kendra

2002-12-01

Photosynthetic microbial mat communities were obtained from marine hypersaline saltern ponds, maintained in a greenhouse facility, and examined for the effects of salinity variations. Because these microbial mats are considered to be useful analogs of ancient marine communities, they offer insights about evolutionary events during the >3 billion year time interval wherein mats co-evolved with Earth's lithosphere and atmosphere. Although photosynthetic mats can be highly dynamic and exhibit extremely high activity, the mats in the present study have been maintained for >1 year with relatively minor changes. The major groups of microorganisms, as assayed using microscopic, genetic, and biomarker methodologies, are essentially the same as those in the original field samples. Field and greenhouse mats were similar with respect to rates of exchange of oxygen and dissolved inorganic carbon across the mat-water interface, both during the day and at night. Field and greenhouse mats exhibited similar rates of efflux of methane and hydrogen. Manipulations of salinity in the water overlying the mats produced changes in the community that strongly resemble those observed in the field. A collaboratory testbed and an array of automated features are being developed to support remote scientific experimentation with the assistance of intelligent software agents. This facility will permit teams of investigators the opportunity to explore ancient environmental conditions that are rare or absent today but that might have influenced the early evolution of these photosynthetic ecosystems.

Motor hypertonia and lack of locomotor coordination in mutant mice lacking DSCAM.

PubMed

Lemieux, Maxime; Laflamme, Olivier D; Thiry, Louise; Boulanger-Piette, Antoine; Frenette, Jérôme; Bretzner, Frédéric

2016-03-01

Down syndrome cell adherence molecule (DSCAM) contributes to the normal establishment and maintenance of neural circuits. Whereas there is abundant literature regarding the role of DSCAM in the neural patterning of the mammalian retina, less is known about motor circuits. Recently, DSCAM mutation has been shown to impair bilateral motor coordination during respiration, thus causing death at birth. DSCAM mutants that survive through adulthood display a lack of locomotor endurance and coordination in the rotarod test, thus suggesting that the DSCAM mutation impairs motor control. We investigated the motor and locomotor functions of DSCAM(2J) mutant mice through a combination of anatomical, kinematic, force, and electromyographic recordings. With respect to wild-type mice, DSCAM(2J) mice displayed a longer swing phase with a limb hyperflexion at the expense of a shorter stance phase during locomotion. Furthermore, electromyographic activity in the flexor and extensor muscles was increased and coactivated over 20% of the step cycle over a wide range of walking speeds. In contrast to wild-type mice, which used lateral walk and trot at walking speed, DSCAM(2J) mice used preferentially less coordinated gaits, such as out-of-phase walk and pace. The neuromuscular junction and the contractile properties of muscles, as well as their muscle spindles, were normal, and no signs of motor rigidity or spasticity were observed during passive limb movements. Our study demonstrates that the DSCAM mutation induces dystonic hypertonia and a disruption of locomotor gaits. Copyright © 2016 the American Physiological Society.

Localized electron transfer rates and microelectrode-based enrichment of microbial communities within a phototrophic microbial mat.

PubMed

Babauta, Jerome T; Atci, Erhan; Ha, Phuc T; Lindemann, Stephen R; Ewing, Timothy; Call, Douglas R; Fredrickson, James K; Beyenal, Haluk

2014-01-01

Phototrophic microbial mats frequently exhibit sharp, light-dependent redox gradients that regulate microbial respiration on specific electron acceptors as a function of depth. In this work, a benthic phototrophic microbial mat from Hot Lake, a hypersaline, epsomitic lake located near Oroville in north-central Washington, was used to develop a microscale electrochemical method to study local electron transfer processes within the mat. To characterize the physicochemical variables influencing electron transfer, we initially quantified redox potential, pH, and dissolved oxygen gradients by depth in the mat under photic and aphotic conditions. We further demonstrated that power output of a mat fuel cell was light-dependent. To study local electron transfer processes, we deployed a microscale electrode (microelectrode) with tip size ~20 μm. To enrich a subset of microorganisms capable of interacting with the microelectrode, we anodically polarized the microelectrode at depth in the mat. Subsequently, to characterize the microelectrode-associated community and compare it to the neighboring mat community, we performed amplicon sequencing of the V1-V3 region of the 16S gene. Differences in Bray-Curtis beta diversity, illustrated by large changes in relative abundance at the phylum level, suggested successful enrichment of specific mat community members on the microelectrode surface. The microelectrode-associated community exhibited substantially reduced alpha diversity and elevated relative abundances of Prosthecochloris, Loktanella, Catellibacterium, other unclassified members of Rhodobacteraceae, Thiomicrospira, and Limnobacter, compared with the community at an equivalent depth in the mat. Our results suggest that local electron transfer to an anodically polarized microelectrode selected for a specific microbial population, with substantially more abundance and diversity of sulfur-oxidizing phylotypes compared with the neighboring mat community.

Localized electron transfer rates and microelectrode-based enrichment of microbial communities within a phototrophic microbial mat

PubMed Central

Babauta, Jerome T.; Atci, Erhan; Ha, Phuc T.; Lindemann, Stephen R.; Ewing, Timothy; Call, Douglas R.; Fredrickson, James K.; Beyenal, Haluk

2014-01-01

Phototrophic microbial mats frequently exhibit sharp, light-dependent redox gradients that regulate microbial respiration on specific electron acceptors as a function of depth. In this work, a benthic phototrophic microbial mat from Hot Lake, a hypersaline, epsomitic lake located near Oroville in north-central Washington, was used to develop a microscale electrochemical method to study local electron transfer processes within the mat. To characterize the physicochemical variables influencing electron transfer, we initially quantified redox potential, pH, and dissolved oxygen gradients by depth in the mat under photic and aphotic conditions. We further demonstrated that power output of a mat fuel cell was light-dependent. To study local electron transfer processes, we deployed a microscale electrode (microelectrode) with tip size ~20 μm. To enrich a subset of microorganisms capable of interacting with the microelectrode, we anodically polarized the microelectrode at depth in the mat. Subsequently, to characterize the microelectrode-associated community and compare it to the neighboring mat community, we performed amplicon sequencing of the V1–V3 region of the 16S gene. Differences in Bray-Curtis beta diversity, illustrated by large changes in relative abundance at the phylum level, suggested successful enrichment of specific mat community members on the microelectrode surface. The microelectrode-associated community exhibited substantially reduced alpha diversity and elevated relative abundances of Prosthecochloris, Loktanella, Catellibacterium, other unclassified members of Rhodobacteraceae, Thiomicrospira, and Limnobacter, compared with the community at an equivalent depth in the mat. Our results suggest that local electron transfer to an anodically polarized microelectrode selected for a specific microbial population, with substantially more abundance and diversity of sulfur-oxidizing phylotypes compared with the neighboring mat community. PMID:24478768

Localized electron transfer rates and microelectrode-based enrichment of microbial communities within a phototrophic microbial mat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Babauta, Jerome T.; Atci, Erhan; Ha, Phuc T.

2014-01-01

Phototrophic microbial mats frequently exhibit sharp, light-dependent redox gradients that regulate microbial respiration on specific electron acceptors as a function of depth. In this work, a benthic phototrophic microbial mat from Hot Lake, a hypersaline, epsomitic lake located near Oroville in north-central Washington, was used to develop a microscale electrochemical method to study local electron transfer processes within the mat. To characterize the physicochemical variables influencing electron transfer, we initially quantified redox potential, pH, and dissolved oxygen gradients by depth in the mat under photic and aphotic conditions. We further demonstrated that power output of a mat fuel cell wasmore » light-dependent. To study local electron transfer processes, we deployed a microscale electrode (microelectrode) with tip size ~20 μm. To enrich a subset of microorganisms capable of interacting with the microelectrode, we anodically polarized the microelectrode at depth in the mat. Subsequently, to characterize the microelectrode- associated community and compare it to the neighboring mat community, we performed amplicon sequencing of the V1-V3 region of the 16S gene. Differences in Bray-Curtis beta diversity, illustrated by large changes in relative abundance at the phylum level, suggested successful enrichment of specific mat community members on the microelectrode surface. The microelectrode-associated community exhibited substantially reduced alpha diversity and elevated relative abundances of Prosthecochloris, Loktanella, Catellibacterium, other unclassified members of Rhodobacteraceae, Thiomicrospira, and Limnobacter, compared with the community at an equivalent depth in the mat. Our results suggest that local electron transfer to an anodically polarized microelectrode selected for a specific microbial population, with substantially more abundance and diversity of sulfur-oxidizing phylotypes compared with the neighboring mat community.« less

Fabrication of a novel scaffold of clotrimazole-microemulsion-containing nanofibers using an electrospinning process for oral candidiasis applications.

PubMed

Tonglairoum, Prasopchai; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Kaomongkolgit, Ruchadaporn; Opanasopit, Praneet

2015-02-01

Clotrimazole (CZ)-loaded microemulsion-containing nanofiber mats were developed as an alternative for oral candidiasis applications. The microemulsion was composed of oleic acid (O), Tween 80 (T80), and a co-surfactant such as benzyl alcohol (BzOH), ethyl alcohol (EtOH) or isopropyl alcohol (IPA). The nanofiber mats were obtained by electrospinning a blended solution of a CZ-loaded microemulsion and a mixed polymer solution of 2% (w/v) chitosan (CS) and 10% (w/v) polyvinyl alcohol (PVA) at a weight ratio of 30:70. The nanofiber mats were characterized using various analytical techniques. The entrapment efficiency, drug release, antifungal activity and cytotoxicity were investigated. The average diameter of the nanofiber mats was in the range of 105.91-125.56 nm. The differential scanning calorimetry (DSC) and powder X-ray diffractometry (PXRD) results revealed the amorphous state of the CZ-loaded microemulsions incorporated into the nanofiber mats. The entrapment efficiency of CZ in the mats was approximately 72.58-98.10%, depended on the microemulsion formulation. The release experiment demonstrated different CZ release characteristics from nanofiber mats prepared using different CZ-loaded microemulsions. The extent of drug release from the fiber mats at 4h was approximately 64.81-74.15%. The release kinetics appeared to follow Higuchi's model. In comparison with CZ lozenges (10mg), the nanofiber mats exhibited more rapid killing activity. Moreover, the nanofiber mats demonstrated desirable mucoadhesive properties and were safe for 2h. Therefore, the nanofiber mats have the potential to be promising candidates for oral candidiasis applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Chlorophyll and carotenoid pigments in solar saltern microbial mats

NASA Astrophysics Data System (ADS)

Villanueva, Joan; Grimalt, Joan O.; de Wit, Rutger; Keely, Brendan J.; Maxwell, James R.

1994-11-01

The distributions of carotenoids, chlorophylls, and their degradation products have been studied in two microbial mat systems developed in the calcite and calcite/gypsum evaporite domains of a solar saltern system. Phormidium valderianum and Microcoleus chthonoplastes are the dominant cyanobacterial species, respectively, and large amounts of Chloroflexus-like bacteria occur in the carbonate/gypsum mat. In both systems, the major pigments are chlorophyll a, zeaxanthin, β-carotene and myxoxanthophyll, which originate from these mat-building cyanobacteria. This common feature contrasts with differences in other pigments that are specific for each mat community. Thus, chlorophyll c and fucoxanthin, reflecting diatom inputs, are only found in the calcite mat, whereas the calcite/gypsum mat contains high concentrations of bacteriochlorophylls c produced by the multicellular green filamentous bacteria. In both cases, the depth concentration profiles (0-30 and 0-40 mm) show a relatively good preservation of the cyanobacterial carotenoids, zeaxanthin, β-carotene, myxoxanthophyll, and echinenone. This contrasts with the extensive biodegradation of cyanobacterial remains observed microscopically. Fucoxanthin in the calcite mat is also transformed at a faster rate than the cyanobacterial carotenoids. Chlorophyll a, the major pigment in both mats, exhibits different transformation pathways. In the calcite/gypsum mat, it is transformed via C-13 2 carbomethoxy defunctionalization prior to loss of the phytyl chain, leading to the formation of pyrophaeophytin a and, subsequently, pyrophaeophorbide a. On the other hand, the occurrence of the enzyme chlorophyllase, attributed to diatoms in the calcite mat, gives rise to extensive phytyl hydrolysis, with the formation of chlorophyllide a, pyrophaeophorbide a and, in minor proportion, phaeophorbide a. Studies of the sources of the photosynthetic pigments and of their transformation pathways in such simplified ecosystems provide a basis for the understanding of the distribution patterns of these compounds in more complex aquatic environments.

Effect of natural fiber types and sodium silicate coated on natural fiber mat/PLA composites: Tensile properties and rate of fire propagation

NASA Astrophysics Data System (ADS)

Thongpin, C.; Srimuk, J.; hipkam, N.; Wachirapong, P.

2015-07-01

In this study, 3 types of natural fibres, i.e. jute, sisal and abaca, were plain weaved to fibre mat. Before weaving, the fibres were treated with 5% NaOH to remove hemi cellulose and lignin. The weaving was performed by hand using square wooden block fit with nails for weaving using one and two types of natural fibres as weft and warp fibre to produce natural fibre mat. The fibre mat was also impregnated in sodium silicate solution extracted from rich husk ash. The pH of the solution was adjusted to pH 7 using H2SO4 before impregnation. After predetermined time, sodium silicate was gelled and deposited on the mat. The fabric mat and sodium silicate coated mat were then impregnated with PLA solution to produce prepreg. Dried pepreg was laminated with PLA sheet using compressing moulding machine to obtain natural fibre mat/PLA composite. The composite containing abaca aligned in longitudinal direction with respect to tension force enhanced Young's modulus more than 300%. Fibre mat composites with abaca aligned in longitudinal direction also showed tensile strength enhancement nearly 400% higher than neat PLA. After coating with sodium silicate, the tensile modulus of the composites was found slightly increased. The silicate coating was disadvantage on tensile strength of the composite due to the effect of sodium hydroxide solution that was used as solvent for silicate extraction from rice husk ash. However, sodium silicate could retard rate of fire propagation about 50%compare to neat PLA and about 10% reduction compared to fibre mat composites without sodium silicate coated fibre mat.

Spatial patterns of cyanobacterial mat growth on sand ripples

NASA Astrophysics Data System (ADS)

Mariotti, G.; Klepac-Ceraj, V.; Perron, J. T.; Bosak, T.

2016-02-01

Photosynthetic microbial mats produce organic matter, cycle nutrients, bind pollutants and stabilize sediment in sandy marine environments. Here, we investigate the influence of bedforms and wave motion on the growth rate, composition and spatial variability of microbial mats by growing cyanobacterial mats on a rippled bed of carbonate sand in a wave tank. The tank was forced with an oscillatory flow with velocities below the threshold for sediment motion yet able to induce a porewater flow within the sediment. Different spatial patterns developed in mats depending on the initial biochemistry of the water medium. When growing in a medium rich in nitrogen, phosphorous and micronutrients, mats grew faster on ripple troughs than on ripple crests. After two months, mats covered the bed surface uniformly, and the microbial communities on the crests and in the troughs had similar compositions. Differences in bed shear stress and nutrient availability between crests and troughs were not able to explain the faster growth in the troughs. We hypothesize that this growth pattern is due to a "strainer" effect, i.e. the suspended bacteria from the inoculum were preferentially delivered to troughs by the wave-induced porewater flow. In the experiments initiated in a medium previously used up by a microbial mat and thus depleted in nutrients, mats grew preferentially on the ripple crests. This spatial pattern persisted for nearly two years, and the microbial composition on troughs and crests was different. We attribute this pattern to the upwelling of porewater in the crests, which increased the delivery of nutrients from sediment to the cyanobacteria on the bed surface. Thus, the macroscopic patterns formed by photosynthetic microbial mats on sand ripples may be used to infer whether mats are nutrient-limited and whether they are recently colonized or older than a month.

Adaptation of a ladder beam walking task to assess locomotor recovery in mice following spinal cord injury.

PubMed

Cummings, Brian J; Engesser-Cesar, Christie; Cadena, Gilbert; Anderson, Aileen J

2007-02-27

Locomotor impairments after spinal cord injury (SCI) are often assessed using open-field rating scales. These tasks have the advantage of spanning the range from complete paralysis to normal walking; however, they lack sensitivity at specific levels of recovery. Additionally, most supplemental assessments were developed in rats, not mice. For example, the horizontal ladder beam has been used to measure recovery in the rat after SCI. This parametric task results in a videotaped archival record of the event, is easily administered, and is unambiguously scored. Although a ladder beam apparatus for mice is available, its use in the assessment of recovery in SCI mice is rare, possibly because normative data for uninjured mice and the type of step misplacements injured mice exhibit is lacking. We report the development of a modified ladder beam instrument and scoring system to measure hindlimb recovery in vertebral T9 contusion spinal cord injured mice. The mouse ladder beam allows for the use of standard parametric statistical tests to assess locomotor recovery. Ladder beam performance is consistent across four strains of mice, there are no sex differences, and inter-rater reliability between observers is high. The ladder beam score is proportional to injury severity and can be used to easily separate mice capable of weight-supported stance up to mice with consistent forelimb to hindlimb coordination. Critically, horizontal ladder beam testing discriminates between mice that score identically in terms of stepping frequency in open-field testing.

Adaptation of a ladder beam walking task to assess locomotor recovery in mice following spinal cord injury

PubMed Central

Cummings, Brian J.; Engesser-Cesar, Christie; Anderson, Aileen J.

2007-01-01

Locomotor impairments after spinal cord injury (SCI) are often assessed using open-field rating scales. These tasks have the advantage of spanning the range from complete paralysis to normal walking; however, they lack sensitivity at specific levels of recovery. Additionally, most supplemental assessments were developed in rats, not mice. For example, the horizontal ladder beam has been used to measure recovery in the rat after SCI. This parametric task results in a videotaped archival record of the event, is easily administered, and is unambiguously scored. Although a ladder beam apparatus for mice is available, its use in the assessment of recovery in SCI mice is rare, possibly because normative data for uninjured mice and the type of step misplacements injured mice exhibit is lacking. We report the development of a modified ladder beam instrument and scoring system to measure hindlimb recovery in vertebral T9 contusion spinal cord injured mice. The mouse ladder beam allows for the use of standard parametric statistical tests to assess locomotor recovery. Ladder beam performance is consistent across four strains of mice, there are no sex differences, and inter-rater reliability between observers is high. The ladder beam score is proportional to injury severity and can be used to easily separate mice capable of weight-supported stance up to mice with consistent forelimb to hindlimb coordination. Critically, horizontal ladder beam testing discriminates between mice that score identically in terms of stepping frequency in open-field testing. PMID:17197044

Orexin neurons are necessary for the circadian control of REM sleep.

PubMed

Kantor, Sandor; Mochizuki, Takatoshi; Janisiewicz, Agnieszka M; Clark, Erika; Nishino, Seiji; Scammell, Thomas E

2009-09-01

The orexin-producing neurons are hypothesized to be essential for the circadian control of sleep/wake behavior, but it remains unknown whether these rhythms are mediated by the orexin peptides or by other signaling molecules released by these neurons such as glutamate or dynorphin. To determine the roles of these neurotransmitters, we examined the circadian rhythms of sleep/wake behavior in mice lacking the orexin neurons (ataxin-3 [Atx] mice) and mice lacking just the orexin neuropeptides (orexin knockout [KO] mice). We instrumented mice for recordings of sleep-wake behavior, locomotor activity (LMA), and body temperature (Tb) and recorded behavior after 6 days in constant darkness. The amplitude of the rapid eye movement (REM) sleep rhythm was substantially reduced in Atx mice but preserved in orexin KO mice. This blunted rhythm in Atx mice was caused by an increase in the amount of REM sleep during the subjective night (active period) due to more transitions into REM sleep and longer REM sleep episodes. In contrast, the circadian variations of Tb, LMA, Wake, non-REM sleep, and cataplexy were normal, suggesting that the circadian timekeeping system and other output pathways are intact in both Atx and KO mice. These results indicate that the orexin neurons are necessary for the circadian suppression of REM sleep. Blunting of the REM sleep rhythm in Atx mice but not in orexin KO mice suggests that other signaling molecules such as dynorphin or glutamate may act in concert with orexins to suppress REM sleep during the active period.

Metagenomic and metabolic profiling of nonlithifying and lithifying stromatolitic mats of Highborne Cay, The Bahamas.

PubMed

Khodadad, Christina L M; Foster, Jamie S

2012-01-01

Stromatolites are laminated carbonate build-ups formed by the metabolic activity of microbial mats and represent one of the oldest known ecosystems on Earth. In this study, we examined a living stromatolite located within the Exuma Sound, The Bahamas and profiled the metagenome and metabolic potential underlying these complex microbial communities. The metagenomes of the two dominant stromatolitic mat types, a nonlithifying (Type 1) and lithifying (Type 3) microbial mat, were partially sequenced and compared. This deep-sequencing approach was complemented by profiling the substrate utilization patterns of the mats using metabolic microarrays. Taxonomic assessment of the protein-encoding genes confirmed previous SSU rRNA analyses that bacteria dominate the metagenome of both mat types. Eukaryotes comprised less than 13% of the metagenomes and were rich in sequences associated with nematodes and heterotrophic protists. Comparative genomic analyses of the functional genes revealed extensive similarities in most of the subsystems between the nonlithifying and lithifying mat types. The one exception was an increase in the relative abundance of certain genes associated with carbohydrate metabolism in the lithifying Type 3 mats. Specifically, genes associated with the degradation of carbohydrates commonly found in exopolymeric substances, such as hexoses, deoxy- and acidic sugars were found. The genetic differences in carbohydrate metabolisms between the two mat types were confirmed using metabolic microarrays. Lithifying mats had a significant increase in diversity and utilization of carbon, nitrogen, phosphorus and sulfur substrates. The two stromatolitic mat types retained similar microbial communities, functional diversity and many genetic components within their metagenomes. However, there were major differences detected in the activity and genetic pathways of organic carbon utilization. These differences provide a strong link between the metagenome and the physiology of the mats, as well as new insights into the biological processes associated with carbonate precipitation in modern marine stromatolites.

UAV, DGPS, and Laser Transit Mapping of Microbial Mat Ecosystems on Little Ambergris Cay, B.W.I.

NASA Astrophysics Data System (ADS)

Stein, N.; Quinn, D. P.; Grotzinger, J. P.; Fischer, W. W.; Knoll, A. H.; Cantine, M.; Gomes, M. L.; Grotzinger, H. M.; Lingappa, U.; Metcalfe, K.; O'Reilly, S. S.; Orzechowski, E. A.; Riedman, L. A.; Strauss, J. V.; Trower, L.

2016-12-01

Little Ambergris Cay is a 6 km long, 1.6 km wide uninhabited island on the Caicos platform in the Turks and Caicos. Little Ambergris provides an analog for the study of microbial mat development in the sedimentary record. Recent field mapping during July of 2016 used UAV- and satellite-based images, differential GPS (DGPS), and total station theodolite (TST) measurements to characterize sedimentology and biofacies across the entirety of Little Ambergris Cay. Nine facies were identified in-situ during DGPS island transects including oolitic grainstone bedrock, sand flats, cutbank and mat-filled channels, hardground-lined bays with EPS-rich mat particles, mangroves, EPS mats, polygonal mats, and mats with blistered surface texture. These facies were mapped onto a 15 cm/pixel visible light orthomosaic of the island generated from more than 1500 nadir images taken by a UAV at 350 m standoff distance. A corresponding stereogrammetric digital elevation map was generated from drone images and 910 DGPS measurements acquired during several island transects. More than 1000 TST measurements provide additional facies elevation constraints, control points for satellite-based water depth calculations, and means to cross-calibrate and reconstruct the topographic profile of bedrock exposed at the beach. Additionally, the thickness of the underlying Holocene sediment fill was estimated over several island transects using a depth probe. Sub-cm resolution drone-based orthophotos of microbial mats were used to quantify polygonal mat size and textures. The mapping results highlight that sedimentary and bio-facies (including mat morphology and fabrics) correlate strongly with elevation. Notably, mat morphology was observed to be highly sensitive to cm-scale variations in topography and water depth. The productivity metric NDVI was computed for mat and vegetation facies using nadir images from a UAV-mounted two-band red-NIR camera. In combination with in situ facies mapping, these measurements provided ground truth for reduction of multispectral Landsat and Worldview-2 satellite images to evaluate mat distribution and diversity across a range of spatial and spectral facies variations.

Characterizing Microbial Mat Morphology with Structure from Motion Techniques in Ice-Covered Lake Joyce, McMurdo Dry Valleys, Antarctica

NASA Astrophysics Data System (ADS)

Mackey, T. J.; Leidman, S. Z.; Allen, B.; Hawes, I.; Lawrence, J.; Jungblut, A. D.; Krusor, M.; Coleman, L.; Sumner, D. Y.

2015-12-01

Structure from Motion (SFM) techniques can provide quantitative morphological documentation of otherwise inaccessible benthic ecosystems such as microbial mats in Lake Joyce, a perennially ice-covered lake of the Antarctic McMurdo Dry Valleys (MDV). Microbial mats are a key ecosystem of MDV lakes, and diverse mat morphologies like pinnacles emerge from interactions among microbial behavior, mineralization, and environmental conditions. Environmental gradients can be isolated to test mat growth models, but assessment of mat morphology along these gradients is complicated by their inaccessibility: the Lake Joyce ice cover is 4-5 m thick, water depths containing diverse pinnacle morphologies are 9-14 m, and relevant mat features are cm-scale. In order to map mat pinnacle morphology in different sedimentary settings, we deployed drop cameras (SeaViewer and GoPro) through 29 GPS referenced drill holes clustered into six stations along a transect spanning 880 m. Once under the ice cover, a boom containing a second GoPro camera was unfurled and rotated to collect oblique images of the benthic mats within dm of the mat-water interface. This setup allowed imaging from all sides over a ~1.5 m diameter area of the lake bottom. Underwater lens parameters were determined for each camera in Agisoft Lens; images were reconstructed and oriented in space with the SFM software Agisoft Photoscan, using the drop camera axis of rotation as up. The reconstructions were compared to downward facing images to assess accuracy, and similar images of an object with known geometry provided a test for expected error in reconstructions. Downward facing images identify decreasing pinnacle abundance in higher sedimentation settings, and quantitative measurements of 3D reconstructions in KeckCAVES LidarViewer supplement these mat morphological facies with measurements of pinnacle height and orientation. Reconstructions also help isolate confounding variables for mat facies trends with measurements of lake bottom slope and underlying relief that could influence pinnacle growth. Comparison of 3D reconstructions to downward-facing drop camera images demonstrate that SFM is a powerful tool for documenting diverse mat morphologies across environmental gradients in ice-covered lakes.

Outcomes of Osteochondral Allograft Transplantation With and Without Concomitant Meniscus Allograft Transplantation: A Comparative Matched Group Analysis.

PubMed

Frank, Rachel M; Lee, Simon; Cotter, Eric J; Hannon, Charles P; Leroux, Timothy; Cole, Brian J

2018-03-01

Osteochondral allograft transplantation (OCA) is often performed with concomitant meniscus allograft transplantation (MAT) as a strategy for knee joint preservation, although to date, the effect of concomitant MAT on outcomes and failure rates after OCA has not been assessed. To determine clinical outcomes for patients undergoing OCA with MAT as compared with a matched cohort of patients undergoing isolated OCA. Control study; Level of evidence, 3. Patients who underwent OCA of the medial or lateral femoral condyle without concomitant MAT by a single surgeon were compared with a matched group of patients who underwent OCA with concomitant MAT (ipsilateral compartment). The patients were matched per age, sex, body mass index, and number of previous ipsilateral knee operations ±1. Patient-reported outcomes, complications, reoperations, and survival rates were compared between groups. One hundred patients undergoing OCA (50 isolated, 50 with MAT) with a mean ± SD follow-up of 4.9 ± 2.7 years (minimum, 2 years) were included (age, 31.7 ± 9.8 years; 52% male). Significantly more patients underwent OCA to the medial femoral condyle (n = 59) than the lateral femoral condyle (n = 41, P < .0001). Patients underwent 2.7 ± 1.7 operations on the ipsilateral knee before OCA. There were no significant differences between the groups regarding reoperation rate (n = 18 for OCA with MAT, n = 17 for OCA without MAT, P = .834), time to reoperation (2.2 ± 2.4 years for OCA with MAT, 3.4 ± 2.7 years for OCA without MAT, P = .149), or failure rates (n = 7 [14%] for OCA with MAT, n = 7 [14%] for OCA without MAT, P > .999). There were no significant differences in patient-reported clinical outcome scores between the groups at final follow-up. There was no significant difference in failure rates between patients undergoing medial femoral condyle OCA (n = 12, 15.3%) and lateral femoral condyle OCA (n = 5, 12.2%, P = .665). These results imply that with appropriate surgical indications to address meniscus deficiency in patients otherwise indicated for OCA and despite the added surgical time and complexity of concomitant MAT, outcomes are favorable, with an 86% OCA graft survivorship at 5 years. This information can be used to counsel patients undergoing OCA with concomitant MAT as part of a knee joint preservation strategy.

Mitigation of Lethal Radiation Syndrome in Mice by Intramuscular Injection of 3D Cultured Adherent Human Placental Stromal Cells

PubMed Central

Gaberman, Elena; Pinzur, Lena; Levdansky, Lilia; Tsirlin, Maria; Netzer, Nir; Aberman, Zami; Gorodetsky, Raphael

2013-01-01

Exposure to high lethal dose of ionizing radiation results in acute radiation syndrome with deleterious systemic effects to different organs. A primary target is the highly sensitive bone marrow and the hematopoietic system. In the current study C3H/HeN mice were total body irradiated by 7.7 Gy. Twenty four hrs and 5 days after irradiation 2×106 cells from different preparations of human derived 3D expanded adherent placental stromal cells (PLX) were injected intramuscularly. Treatment with batches consisting of pure maternal cell preparations (PLX-Mat) increased the survival of the irradiated mice from ∼27% to 68% (P<0.001), while cell preparations with a mixture of maternal and fetal derived cells (PLX-RAD) increased the survival to ∼98% (P<0.0001). The dose modifying factor of this treatment for both 50% and 37% survival (DMF50 and DMF37) was∼1.23. Initiation of the more effective treatment with PLX-RAD injection could be delayed for up to 48 hrs after irradiation with similar effect. A delayed treatment by 72 hrs had lower, but still significantly effect (p<0.05). A faster recovery of the BM and improved reconstitution of all blood cell lineages in the PLX-RAD treated mice during the follow-up explains the increased survival of the cells treated irradiated mice. The number of CD45+/SCA1+ hematopoietic progenitor cells within the fast recovering population of nucleated BM cells in the irradiated mice was also elevated in the PLX-RAD treated mice. Our study suggests that IM treatment with PLX-RAD cells may serve as a highly effective “off the shelf” therapy to treat BM failure following total body exposure to high doses of radiation. The results suggest that similar treatments may be beneficial also for clinical conditions associated with severe BM aplasia and pancytopenia. PMID:23823334

Mitigation of Lethal Radiation Syndrome in Mice by Intramuscular Injection of 3D Cultured Adherent Human Placental Stromal Cells.

PubMed

Gaberman, Elena; Pinzur, Lena; Levdansky, Lilia; Tsirlin, Maria; Netzer, Nir; Aberman, Zami; Gorodetsky, Raphael

2013-01-01

Exposure to high lethal dose of ionizing radiation results in acute radiation syndrome with deleterious systemic effects to different organs. A primary target is the highly sensitive bone marrow and the hematopoietic system. In the current study C3H/HeN mice were total body irradiated by 7.7 Gy. Twenty four hrs and 5 days after irradiation 2×10(6) cells from different preparations of human derived 3D expanded adherent placental stromal cells (PLX) were injected intramuscularly. Treatment with batches consisting of pure maternal cell preparations (PLX-Mat) increased the survival of the irradiated mice from ∼27% to 68% (P<0.001), while cell preparations with a mixture of maternal and fetal derived cells (PLX-RAD) increased the survival to ∼98% (P<0.0001). The dose modifying factor of this treatment for both 50% and 37% survival (DMF50 and DMF37) was∼1.23. Initiation of the more effective treatment with PLX-RAD injection could be delayed for up to 48 hrs after irradiation with similar effect. A delayed treatment by 72 hrs had lower, but still significantly effect (p<0.05). A faster recovery of the BM and improved reconstitution of all blood cell lineages in the PLX-RAD treated mice during the follow-up explains the increased survival of the cells treated irradiated mice. The number of CD45+/SCA1+ hematopoietic progenitor cells within the fast recovering population of nucleated BM cells in the irradiated mice was also elevated in the PLX-RAD treated mice. Our study suggests that IM treatment with PLX-RAD cells may serve as a highly effective "off the shelf" therapy to treat BM failure following total body exposure to high doses of radiation. The results suggest that similar treatments may be beneficial also for clinical conditions associated with severe BM aplasia and pancytopenia.

Alternative pathways for phosphonate metabolism in thermophilic cyanobacteria from microbial mats

PubMed Central

Gomez-Garcia, Maria R; Davison, Michelle; Blain-Hartnung, Matthew; Grossman, Arthur R; Bhaya, Devaki

2011-01-01

Synechococcus sp. represents an ecologically diverse group of cyanobacteria found in numerous environments, including hot-spring microbial mats, where they are spatially distributed along thermal, light and oxygen gradients. These thermophiles engage in photosynthesis and aerobic respiration during the day, but switch to fermentative metabolism and nitrogen fixation at night. The genome of Synechococcus OS-B′, isolated from Octopus Spring (Yellowstone National Park) contains a phn gene cluster encoding a phosphonate (Phn) transporter and a C–P lyase. A closely related isolate, Synechococcus OS-A, lacks this cluster, but contains genes encoding putative phosphonatases (Phnases) that appear to be active only in the presence of the Phn substrate. Both isolates grow well on several different Phns as a sole phosphorus (P) source. Interestingly, Synechococcus OS-B′ can use the organic carbon backbones of Phns for heterotrophic growth in the dark, whereas in the light this strain releases organic carbon from Phn as ethane or methane (depending on the specific Phn available); Synechococcus OS-A has neither of these capabilities. These differences in metabolic strategies for assimilating the P and C of Phn by two closely related Synechococcus spp. are suggestive of niche-specific constraints in the evolution of nutrient assimilation pathways and syntrophic relationships among the microbial populations of the hot-spring mats. Thus, it is critical to evaluate levels of various P sources, including Phn, in thermally active habitats and the potential importance of these compounds in the biogeochemical cycling of P and C (some Phn compounds also contain N) in diverse terrestrial environments. PMID:20631809

Carbonate mineralisation in sabkha microbial mats; a comparative study of field and laboratory systems

NASA Astrophysics Data System (ADS)

Dutton, Kirsten E.; Paul, Andreas; Lessa Andrade, Luiza; Sherry, Angela; Lokier, Stephen; Head, Ian M.; van der Land, Cees

2017-04-01

Microbial mats and their lithified counterparts are some of the earliest evidence of life on Earth. The coastal sabkha in Abu Dhabi, United Arab Emirates, is a modern setting where microbial mats flourish in a hypersaline and arid environment. These microbial communities are composed of microbes such as cyanobacteria, thermoplasmata and sulphate-reducing bacteria. The mats thrive as they are protected from predators, which are excluded by the extreme environmental conditions. Microbial mats are highly reactive to change, with their microbial communities and geochemistry varying on a millimetre scale, likely controlling mineralisation processes. Exact carbonate mineralisation rates within coastal sabkha microbial mats have not to date been quantified. Defining the mineralisation pathways and knowledge of precise mineralisation rates will help to explain how these organosedimentary structures are retained in the rock record. A fundamental understanding of the role of microbial mats in the formation of different carbonate phases is important, yet there are also other practical implications. For example, structures observed in core from the oil-bearing Arab Formation have been likened to modern microbial mats in terms of structure and mineralogy. The depositional configuration and primary mineralogy generated by microbial mats may control syndepositional lithification and later diagenesis thereby influencing reservoir porosity and permeability. In order to constrain factors effecting mineralisation and early lithification, experimentation in a controlled laboratory environment is required. Parameters for experimentation have been established during fieldwork and were applied to a tank-based laboratory simulation of sabkha microbial mats. These parameters include light, salinity and cation and anion water chemistry, gas production chemistry and vertical mat growth. Parameters were measured weekly with sampling for mineralogical and microbial community analysis on a biweekly basis. In addition to these parameter measurements already in place in current experiments, temperature and tidal cycle were monitored in the field. Over the course of the first three months, the microbial mat, which was submerged in an artificial seawater medium, grew vertically and developed a green surface at the top and sides. Thermogravimetric analysis has established that the top 1 mm surface mat biomass contains carbonate minerals, leading to an initial inferred carbonate mineralisation rate of approximately 0.5 g per 1 cm2 per year (approx. per 10 g surface mat material). This rate of mineralisation will become more accurate as more analysis is completed particularly comparing samples of mat, initially before they went in to the tank experiment and after incremental time periods, 3 months, 6 months etc. Further analysis of mat growth will establish the extent to which the precipitated carbonate minerals result from microbial activity and the types of minerals precipitated. The rate of mineralisation can be scaled-up to the km scale with the potential to isolate mineralisation rates promoted by different communities and in different types of microbial mat.

DNA vaccination with a plasmid encoding LACK-TSA fusion against Leishmania major infection in BALB/c mice.

PubMed

Maspi, N; Ghaffarifar, F; Sharifi, Z; Dalimi, A; Khademi, S Z

2017-12-01

Vaccination would be the most important strategy for the prevention and elimination of leishmaniasis. The aim of the present study was to compare the immune responses induced following DNA vaccination with LACK (Leishmania analogue of the receptor kinase C), TSA (Thiol-specific-antioxidant) genes alone or LACK-TSA fusion against cutaneous leishmaniasis (CL). Cellular and humoral immune responses were evaluated before and after challenge with Leishmania major (L. major). In addition, the mean lesion size was also measured from 3th week post-infection. All immunized mice showed a partial immunity characterized by higher interferon (IFN)-γ and Immunoglobulin G (IgG2a) levels compared to control groups (p<0.05). IFN-γ/ Interleukin (IL)-4 and IgG2a/IgG1 ratios demonstrated the highest IFN-γ and IgG2a levels in the group receiving LACK-TSA fusion. Mean lesion sizes reduced significantly in all immunized mice compared with control groups at 7th week post-infection (p<0.05). In addition, there was a significant reduction in mean lesion size of LACK-TSA and TSA groups than LACK group after challenge (p<0.05). In the present study, DNA immunization promoted Th1 immune response and confirmed the previous observations on immunogenicity of LACK and TSA antigens against CL. Furthermore, this study demonstrated that a bivalent vaccine can induce stronger immune responses and protection against infectious challenge with L. major.

Epicutaneous challenge of orally immunized mice redirects antigen-specific gut-homing T cells to the skin.

PubMed

Oyoshi, Michiko K; Elkhal, Abdallah; Scott, Jordan E; Wurbel, Marc-Andre; Hornick, Jason L; Campbell, James J; Geha, Raif S

2011-06-01

Patients with atopic dermatitis (AD) often suffer from food allergy and develop flares upon skin contact with food allergens. However, it is unclear whether T cells sensitized to allergens in the gut promote this skin inflammation. To address this question, we orally immunized WT mice and mice lacking the skin-homing chemokine receptor Ccr4 (Ccr4-/- mice) with OVA and then challenged them epicutaneously with antigen. Allergic skin inflammation developed in the WT mice but not in the mutants and was characterized by epidermal thickening, dermal infiltration by eosinophils and CD4+ T cells, and upregulation of Th2 cytokines. T cells purified from mesenteric lymph nodes (MLNs) of orally immunized WT mice transferred allergic skin inflammation to naive recipients cutaneously challenged with antigen, but this effect was lost in T cells purified from Ccr4-/- mice. In addition, the ability of adoptively transferred OVA-activated T cells to home to the skin following cutaneous OVA challenge was ablated in mice that lacked lymph nodes. These results indicate that cutaneous exposure to food antigens can reprogram gut-homing effector T cells in LNs to express skin-homing receptors, eliciting skin lesions upon food allergen contact in orally sensitized AD patients.

Comparison of body weight and gene expression in amelogenin null and wild-type mice.

PubMed

Li, Yong; Yuan, Zhi-An; Aragon, Melissa A; Kulkarni, Ashok B; Gibson, Carolyn W

2006-05-01

Amelogenin (AmelX) null mice develop hypomineralized enamel lacking normal prism structure, but are healthy and fertile. Because these mice are smaller than wild-type mice prior to weaning, we undertook a detailed analysis of the weight of mice and analyzed AmelX expression in non-dental tissues. Wild-type mice had a greater average weight each day within the 3-wk period. Using reverse transcription-polymerase chain reaction (RT-PCR), products of approximately 200 bp in size were generated from wild-type teeth, brain, eye, and calvariae. DNA sequence analysis of RT-PCR products from calvariae indicated that the small amelogenin leucine-rich amelogenin peptide (LRAP), both with and without exon 4, was expressed. No products were obtained from any of the samples from the AmelX null mice. We also isolated mRNAs that included AmelX exons 8 and 9, and identified a duplication within the murine AmelX gene with 91% homology. Our results add additional support to the hypothesis that amelogenins are multifunctional proteins, with potential roles in non-ameloblasts and in non-mineralizing tissues during development. The smaller size of AmelX null mice could potentially be explained by the lack of LRAP expression in some of these tissues, leading to a delay in development.

Cerebral amyloid angiopathy increases susceptibility to infarction after focal cerebral ischemia in Tg2576 mice.

PubMed

Milner, Eric; Zhou, Meng-Liang; Johnson, Andrew W; Vellimana, Ananth K; Greenberg, Jacob K; Holtzman, David M; Han, Byung Hee; Zipfel, Gregory J

2014-10-01

We and others have shown that soluble amyloid β-peptide (Aβ) and cerebral amyloid angiopathy (CAA) cause significant cerebrovascular dysfunction in mutant amyloid precursor protein (APP) mice, and that these deficits are greater in aged APP mice having CAA compared with young APP mice lacking CAA. Amyloid β-peptide in young APP mice also increases infarction after focal cerebral ischemia, but the impact of CAA on ischemic brain injury is unknown. To determine this, we assessed cerebrovascular reactivity, cerebral blood flow (CBF), and extent of infarction and neurological deficits after transient middle cerebral artery occlusion in aged APP mice having extensive CAA versus young APP mice lacking CAA (and aged-matched littermate controls). We found that aged APP mice have more severe cerebrovascular dysfunction that is CAA dependent, have greater CBF compromise during and immediately after middle cerebral artery occlusion, and develop larger infarctions after middle cerebral artery occlusion. These data indicate CAA induces a more severe form of cerebrovascular dysfunction than amyloid β-peptide alone, leading to intra- and postischemic CBF deficits that ultimately exacerbate cerebral infarction. Our results shed mechanistic light on human studies identifying CAA as an independent risk factor for ischemic brain injury. © 2014 American Heart Association, Inc.

Post-exposure vaccination with MP-12 lacking NSs protects mice against lethal Rift Valley fever virus challenge.

PubMed

Gowen, Brian B; Bailey, Kevin W; Scharton, Dionna; Vest, Zachery; Westover, Jonna B; Skirpstunas, Ramona; Ikegami, Tetsuro

2013-05-01

Rift Valley fever virus (RVFV) causes severe disease in humans and livestock. There are currently no approved antivirals or vaccines for the treatment or prevention of RVF disease in humans. A major virulence factor of RVFV is the NSs protein, which inhibits host transcription including the interferon (IFN)-β gene and promotes the degradation of dsRNA-dependent protein kinase, PKR. We analyzed the efficacy of the live-attenuated MP-12 vaccine strain and MP-12 variants that lack the NSs protein as post-exposure vaccinations. Although parental MP-12 failed to elicit a protective effect in mice challenged with wild-type (wt) RVFV by the intranasal route, significant protection was demonstrated by vaccination with MP-12 strains lacking NSs when they were administered at 20-30 min post-exposure. Viremia and virus replication in liver, spleen and brain were also inhibited by post-exposure vaccination with MP-12 lacking NSs. The protective effect was mostly lost when vaccination was delayed 6 or 24 h after intranasal RVFV challenge. When mice were challenged subcutaneously, efficacy of MP-12 lacking NSs was diminished, most likely due to more rapid dissemination of wt RVFV. Our findings suggest that post-exposure vaccination with MP-12 lacking NSs may be developed as a novel post-exposure treatment to prevent RVF. Copyright © 2013 Elsevier B.V. All rights reserved.

Vaginal Exposure to Zika Virus during Pregnancy Leads to Fetal Brain Infection.

PubMed

Yockey, Laura J; Varela, Luis; Rakib, Tasfia; Khoury-Hanold, William; Fink, Susan L; Stutz, Bernardo; Szigeti-Buck, Klara; Van den Pol, Anthony; Lindenbach, Brett D; Horvath, Tamas L; Iwasaki, Akiko

2016-08-25

Zika virus (ZIKV) can be transmitted sexually between humans. However, it is unknown whether ZIKV replicates in the vagina and impacts the unborn fetus. Here, we establish a mouse model of vaginal ZIKV infection and demonstrate that, unlike other routes, ZIKV replicates within the genital mucosa even in wild-type (WT) mice. Mice lacking RNA sensors or transcription factors IRF3 and IRF7 resulted in higher levels of local viral replication. Furthermore, mice lacking the type I interferon (IFN) receptor (IFNAR) became viremic and died of infection after a high-dose vaginal ZIKV challenge. Notably, vaginal infection of pregnant dams during early pregnancy led to fetal growth restriction and infection of the fetal brain in WT mice. This was exacerbated in mice deficient in IFN pathways, leading to abortion. Our study highlights the vaginal tract as a highly susceptible site of ZIKV replication and illustrates the dire disease consequences during pregnancy. Copyright © 2016 Elsevier Inc. All rights reserved.

Ectomycorrhizal mats alter forest soil biogeochemistry

Treesearch

Laurel A. Kluber; Kathryn M. Tinnesand; Bruce A. Caldwell; Susie M. Dunham; Rockie R. Yarwood; Peter J. Bottomley; David D. Myrold

2010-01-01

Dense hyphal mats formed by ectomycorrhizal (EcM) fungi are prominent features in Douglas-fir forest ecosystems, and have been estimated to cover up to 40% of the soil surface in some forest stands. Two morphotypes of EcM mats have been previously described: rhizomorphic mats, which have thick hyphal rhizomorphs and are found primarily in the organic horizon, and...

Ultrafine polybenzimidazole (PBI) fibers. [separators for alkaline batteries and dfuel cells

NASA Technical Reports Server (NTRS)

Chenevey, E. C.

1979-01-01

Mats were made from ultrafine polybenzimidazole (PBI) fibers to provide an alternate to the use of asbestos as separators in fuel cells and alkaline batteries. To minimize distortion during mat drying, a process to provide a dry fibrid was developed. Two fibrid types were developed: one coarse, making mats for battery separators; the other fine, making low permeability matrices for fuel cells. Eventually, it was demonstrated that suitable mat fabrication techniques yielded fuel cell separators from the coarser alkaline battery fibrids. The stability of PBI mats to 45% KOH at 123 C can be increased by heat treatment at high temperatures. Weight loss data to 1000 hours exposure show the alkali resistance of the mats to be superior to that of asbestos.

Analysis of bacterial and archaeal diversity in coastal microbial mats using massive parallel 16S rRNA gene tag sequencing.

PubMed

Bolhuis, Henk; Stal, Lucas J

2011-11-01

Coastal microbial mats are small-scale and largely closed ecosystems in which a plethora of different functional groups of microorganisms are responsible for the biogeochemical cycling of the elements. Coastal microbial mats play an important role in coastal protection and morphodynamics through stabilization of the sediments and by initiating the development of salt-marshes. Little is known about the bacterial and especially archaeal diversity and how it contributes to the ecological functioning of coastal microbial mats. Here, we analyzed three different types of coastal microbial mats that are located along a tidal gradient and can be characterized as marine (ST2), brackish (ST3) and freshwater (ST3) systems. The mats were sampled during three different seasons and subjected to massive parallel tag sequencing of the V6 region of the 16S rRNA genes of Bacteria and Archaea. Sequence analysis revealed that the mats are among the most diverse marine ecosystems studied so far and consist of several novel taxonomic levels ranging from classes to species. The diversity between the different mat types was far more pronounced than the changes between the different seasons at one location. The archaeal community for these mats have not been studied before and revealed a strong reaction on a short period of draught during summer resulting in a massive increase in halobacterial sequences, whereas the bacterial community was barely affected. We concluded that the community composition and the microbial diversity were intrinsic of the mat type and depend on the location along the tidal gradient indicating a relation with salinity.

Structure and function of natural sulphide-oxidizing microbial mats under dynamic input of light and chemical energy

PubMed Central

Klatt, Judith M; Meyer, Steffi; Häusler, Stefan; Macalady, Jennifer L; de Beer, Dirk; Polerecky, Lubos

2016-01-01

We studied the interaction between phototrophic and chemolithoautotrophic sulphide-oxidizing microorganisms in natural microbial mats forming in sulphidic streams. The structure of these mats varied between two end-members: one characterized by a layer dominated by large sulphur-oxidizing bacteria (SOB; mostly Beggiatoa-like) on top of a cyanobacterial layer (B/C mats) and the other with an inverted structure (C/B mats). C/B mats formed where the availability of oxygen from the water column was limited (<5 μm). Aerobic chemolithotrophic activity of the SOB depended entirely on oxygen produced locally by cyanobacteria during high light conditions. In contrast, B/C mats formed at locations where oxygen in the water column was comparatively abundant (>45 μM) and continuously present. Here SOB were independent of the photosynthetic activity of cyanobacteria and outcompeted the cyanobacteria in the uppermost layer of the mat where energy sources for both functional groups were concentrated. Outcompetition of photosynthetic microbes in the presence of light was facilitated by the decoupling of aerobic chemolithotrophy and oxygenic phototrophy. Remarkably, the B/C mats conserved much less energy than the C/B mats, although similar amounts of light and chemical energy were available. Thus ecosystems do not necessarily develop towards optimal energy usage. Our data suggest that, when two independent sources of energy are available, the structure and activity of microbial communities is primarily determined by the continuous rather than the intermittent energy source, even if the time-integrated energy flux of the intermittent energy source is greater. PMID:26405833

Poly(L-lactide)/halloysite nanotube electrospun mats as dual-drug delivery systems and their therapeutic efficacy in infected full-thickness burns.

PubMed

Zhang, Xiazhi; Guo, Rui; Xu, Jiqing; Lan, Yong; Jiao, Yanpeng; Zhou, Changren; Zhao, Yaowu

2015-11-01

In this study, poly(L-lactide) (PLLA)/halloysite nanotube (HNT) electrospun mats were prepared as a dual-drug delivery system. HNTs were used to encapsulate polymyxin B sulphate (a hydrophilic drug). Dexamethasone (a hydrophobic drug) was directly dissolved in the PLLA solution. The drug-loaded HNTs with optimised encapsulation efficiency were then mixed with the PLLA solution for subsequent electrospinning to form composite dual-drug-loaded fibre mats. The structure, morphology, degradability and mechanical properties of the electrospun composite mats were characterised in detail. The results showed that the HNTs were uniformly distributed in the composite PLLA mats. The HNTs content in the mats could change the morphology and average diameter of the electrospun fibres. The HNTs improved both the tensile strength of the PLLA electrospun mats and their degradation ratio. The drug-release kinetics of the electrospun mats were investigated using ultraviolet-visible spectrophotometry. The HNTs/PLLA ratio could be varied to adjust the release of polymyxin B sulphate and dexamethasone. The antibacterial activity in vitro of the mats was evaluated using agar diffusion and turbidimetry tests, which indicated the antibacterial efficacy of the dual-drug delivery system against Gram-positive and -negative bacteria. Healing in vivo of infected full-thickness burns and infected wounds was investigated by macroscopic observation, histological observation and immunohistochemical staining. The results indicated that the electrospun mats were capable of co-loading and co-delivering hydrophilic and hydrophobic drugs, and could potentially be used as novel antibacterial wound dressings. © The Author(s) 2015.

Magnetoacoustic Tomography with Magnetic Induction (MAT-MI) for Imaging Electrical Conductivity of Biological Tissue: A Tutorial Review

PubMed Central

Li, Xu; Yu, Kai; He, Bin

2016-01-01

Magnetoacoustic tomography with magnetic induction (MAT-MI) is a noninvasive imaging method developed to map electrical conductivity of biological tissue with millimeter level spatial resolution. In MAT-MI, a time-varying magnetic stimulation is applied to induce eddy current inside the conductive tissue sample. With the existence of a static magnetic field, the Lorentz force acting on the induced eddy current drives mechanical vibrations producing detectable ultrasound signals. These ultrasound signals can then be acquired to reconstruct a map related to the sample’s electrical conductivity contrast. This work reviews fundamental ideas of MAT-MI and major techniques developed in these years. First, the physical mechanisms underlying MAT-MI imaging are described including the magnetic induction and Lorentz force induced acoustic wave propagation. Second, experimental setups and various imaging strategies for MAT-MI are reviewed and compared together with the corresponding experimental results. In addition, as a recently developed reverse mode of MAT-MI, magneto-acousto-electrical tomography with magnetic induction (MAET-MI) is briefly reviewed in terms of its theory and experimental studies. Finally, we give our opinions on existing challenges and future directions for MAT-MI research. With all the reported and future technical advancement, MAT-MI has the potential to become an important noninvasive modality for electrical conductivity imaging of biological tissue. PMID:27542088

The green alga, Cladophora, promotes Escherichia coli growth and contamination of recreational waters in Lake Michigan

USGS Publications Warehouse

Heuvel, A.V.; McDermott, C.; Pillsbury, R.; Sandrin, T.; Kinzelman, J.; Ferguson, J.; Sadowsky, M.; Byappanahalli, M.; Whitman, R.; Kleinheinz, G.T.

2010-01-01

A linkage between Cladophora mats and exceedances of recreational water quality criteria has been suggested, but not directly studied. Th is study investigates the spatial and temporal association between Escherichia coli concentrations within and near Cladophora mats at two northwestern Lake Michigan beaches in Door County, Wisconsin. Escherichia coli concentrations in water underlying mats were significantly greater than surrounding water (p < 0.001). Below mat E. coli increased as the stranded mats persisted at the beach swash zone. Water adjacent to Cladophora mats had lower E. coli concentrations, but surpassed EPA swimming criteria the majority of sampling days. A signifi cant positive association was found between E. coli concentrations attached to Cladophora and in underlying water (p < 0.001). The attached E. coli likely acted as a reservoir for populating water underlying the mat. Fecal bacterial pathogens, however, could not be detected by microbiological culture methods either attached to mat biomass or in underlying water. Removal of Cladophora mats from beach areas may improve aesthetic and microbial water quality at affected beaches. These associations and potential natural growth of E. coli in bathing waters call into question the efficacy of using E. coli as a recreational water quality indicator of fecal contaminations. Copyright ?? 2010 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

The ichthyofauna of drifting macrophyte mats in the Ivinhema River, upper Paraná River basin, Brazil

USGS Publications Warehouse

Bulla, C. K.; Gomes, Luiz Carlos; Miranda, Leandro E.; Agostinho, A. A.

2011-01-01

We describe the fish assemblages associated with drifting macrophyte mats and consider their possible role as dispersal vectors in the Ivinhema River, a major tributary of the upper Paraná River, Brazil. Fish associated with drifting mats were sampled in the main river channel during January and March 2005, when the wind and/or the increased water level were sufficient to transport macrophyte stands. Fish in the drifting mats were sampled with a floating sieve (4 m long x 2 m wide x 0.6 m high, and 2 mm mesh size). In the laboratory, larvae, juvenile, and adult fish were counted and identified to the lowest possible taxonomic level. In four drifting macrophyte mats we captured 218 individuals belonging to at least 28 species, 17 families, and 6 orders. Aphyocharax dentatus, Serrasalmus spp., and Trachelyopterus galeatus were the most abundant taxa associated with the mats, but species richness ranged from 6 to 24 species per mat. In addition, 85% of the total number of individuals caught was larvae and juveniles. Although preliminary and based on limited samples, this study of drifting macrophyte mats was the first one in the last unregulated stretch of the Paraná River remaining inside Brazilian territory, and alerts us to the potential role of macrophytes mats as dispersers of fish species in the region.

Methylmercury enters an aquatic food web through acidophilic microbial mats in Yellowstone National Park, Wyoming.

PubMed

Boyd, Eric S; King, Susan; Tomberlin, Jeffery K; Nordstrom, D Kirk; Krabbenhoft, David P; Barkay, Tamar; Geesey, Gill G

2009-04-01

Microbial mats are a visible and abundant life form inhabiting the extreme environments in Yellowstone National Park (YNP), WY, USA. Little is known of their role in food webs that exist in the Park's geothermal habitats. Eukaryotic green algae associated with a phototrophic green/purple Zygogonium microbial mat community that inhabits low-temperature regions of acidic (pH approximately 3.0) thermal springs were found to serve as a food source for stratiomyid (Diptera: Stratiomyidae) larvae. Mercury in spring source water was taken up and concentrated by the mat biomass. Monomethylmercury compounds (MeHg(+)), while undetectable or near the detection limit (0.025 ng l(-1)) in the source water of the springs, was present at concentrations of 4-7 ng g(-1) dry weight of mat biomass. Detection of MeHg(+) in tracheal tissue of larvae grazing the mat suggests that MeHg(+) enters this geothermal food web through the phototrophic microbial mat community. The concentration of MeHg(+) was two to five times higher in larval tissue than mat biomass indicating MeHg(+) biomagnification occurred between primary producer and primary consumer trophic levels. The Zygogonium mat community and stratiomyid larvae may also play a role in the transfer of MeHg(+) to species in the food web whose range extends beyond a particular geothermal feature of YNP.

Attenuated traumatic axonal injury and improved functional outcome after traumatic brain injury in mice lacking Sarm1.

PubMed

Henninger, Nils; Bouley, James; Sikoglu, Elif M; An, Jiyan; Moore, Constance M; King, Jean A; Bowser, Robert; Freeman, Marc R; Brown, Robert H

2016-04-01

Axonal degeneration is a critical, early event in many acute and chronic neurological disorders. It has been consistently observed after traumatic brain injury, but whether axon degeneration is a driver of traumatic brain injury remains unclear. Molecular pathways underlying the pathology of traumatic brain injury have not been defined, and there is no efficacious treatment for traumatic brain injury. Here we show that mice lacking the mouse Toll receptor adaptor Sarm1 (sterile α/Armadillo/Toll-Interleukin receptor homology domain protein) gene, a key mediator of Wallerian degeneration, demonstrate multiple improved traumatic brain injury-associated phenotypes after injury in a closed-head mild traumatic brain injury model. Sarm1(-/-) mice developed fewer β-amyloid precursor protein aggregates in axons of the corpus callosum after traumatic brain injury as compared to Sarm1(+/+) mice. Furthermore, mice lacking Sarm1 had reduced plasma concentrations of the phophorylated axonal neurofilament subunit H, indicating that axonal integrity is maintained after traumatic brain injury. Strikingly, whereas wild-type mice exibited a number of behavioural deficits after traumatic brain injury, we observed a strong, early preservation of neurological function in Sarm1(-/-) animals. Finally, using in vivo proton magnetic resonance spectroscopy we found tissue signatures consistent with substantially preserved neuronal energy metabolism in Sarm1(-/-) mice compared to controls immediately following traumatic brain injury. Our results indicate that the SARM1-mediated prodegenerative pathway promotes pathogenesis in traumatic brain injury and suggest that anti-SARM1 therapeutics are a viable approach for preserving neurological function after traumatic brain injury. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

G protein-gated K+ channel ablation in forebrain pyramidal neurons selectively impairs fear learning

PubMed Central

Victoria, Nicole C.; de Velasco, Ezequiel Marron Fernandez; Ostrovskaya, Olga; Metzger, Stefania; Xia, Zhilian; Kotecki, Lydia; Benneyworth, Michael A.; Zink, Anastasia N.; Martemyanov, Kirill A.; Wickman, Kevin

2015-01-01

Background Cognitive dysfunction occurs in many debilitating conditions including Alzheimer’s disease, Down syndrome, schizophrenia, and mood disorders. The dorsal hippocampus is a critical locus of cognitive processes linked to spatial and contextual learning. G protein-gated inwardly rectifying K+ (GIRK/Kir3) channels, which mediate the postsynaptic inhibitory effect of many neurotransmitters, have been implicated in hippocampal-dependent cognition. Available evidence, however, derives primarily from constitutive gain-of-function models that lack cellular specificity. Methods We used constitutive and neuron-specific gene ablation models targeting an integral subunit of neuronal GIRK channels (GIRK2) to probe the impact of GIRK channels on associative learning and memory. Results Constitutive Girk2−/− mice exhibited a striking deficit in hippocampal-dependent (contextual) and hippocampal-independent (cue) fear conditioning. Mice lacking GIRK2 in GABA neurons (GAD-Cre:Girk2flox/flox mice) exhibited a clear deficit in GIRK-dependent signaling in dorsal hippocampal GABA neurons, but no evident behavioral phenotype. Mice lacking GIRK2 in forebrain pyramidal neurons (CaMKII-Cre(+):Girk2flox/flox mice) exhibited diminished GIRK-dependent signaling in dorsal, but not ventral, hippocampal pyramidal neurons. CaMKII-Cre(+):Girk2flox/flox mice also displayed a selective impairment in contextual fear conditioning, as both cue-fear and spatial learning were intact in these mice. Finally, loss of GIRK2 in forebrain pyramidal neurons correlated with enhanced long-term depression and blunted depotentiation of long-term potentiation at the Schaffer collateral/CA1 synapse in the dorsal hippocampus. Conclusions Our data suggest that GIRK channels in dorsal hippocampal pyramidal neurons are necessary for normal learning involving aversive stimuli, and support the contention that dysregulation of GIRK-dependent signaling may underlie cognitive dysfunction in some disorders. PMID:26612516

Mammary ductal growth is impaired in mice lacking leptin-dependent signal transducer and activator of transcription 3 signaling.

PubMed

Thorn, Stephanie R; Giesy, Sarah L; Myers, Martin G; Boisclair, Yves R

2010-08-01

Mice lacking leptin (ob/ob) or its full-length receptor (db/db) are obese and reproductively incompetent. Fertility, pregnancy, and lactation are restored, respectively, in ob/ob mice treated with leptin through mating, d 6.5 post coitum, and pregnancy. Therefore, leptin signaling is needed for lactation, but the timing of its action and the affected mammary process remain unknown. To address this issue, we used s/s mice lacking only leptin-dependent signal transducer and activator of transcription (STAT)3 signaling. These mice share many features with db/db mice, including obesity, but differ by retaining sufficient activity of the hypothalamic-pituitary-ovarian axis to support reproduction. The s/s mammary epithelium was normal at 3 wk of age but failed to expand through the mammary fat pad (MFP) during the subsequent pubertal period. Ductal growth failure was not corrected by estrogen therapy and did not relate to inadequate IGF-I production by the MFP or to the need for epithelial or stromal leptin-STAT3 signaling. Ductal growth failure coincided with adipocyte hypertrophy and increased MFP production of leptin, TNFalpha, and IL6. These cytokines, however, were unable to inhibit the proliferation of a collection of mouse mammary epithelial cell lines. In conclusion, the very first step of postnatal mammary development fails in s/s mice despite sufficient estrogen IGF-I and an hypothalamic-pituitary-ovarian axis capable of supporting reproduction. This failure is not caused by mammary loss of leptin-dependent STAT3 signaling or by the development of inflammation. These data imply the existence of an unknown mechanism whereby leptin-dependent STAT3 signaling and obesity alter mammary ductal development.

Mulching effects of plant fiber and plant fiber-polyester mats combined with fertilizer on loblslly pine seedlings

Treesearch

James D. Haywood; John A. Youngquist

1991-01-01

In this preliminary study, several mattings, combined with and without fertilizer application, were tested around newly planted loblolly, pine (Pinus taeda L.) seedlings. After 9 months in the field, jute- polyester and jute mats had similar survival rates relitive to controls, but hemlock-po1yvester mats had depressed survival when used in...

The micromorphology of Younger Dryas-aged black mats from Nevada, Arizona, Texas and New Mexico

NASA Astrophysics Data System (ADS)

Harris-Parks, Erin

2016-01-01

Black mats are organic-rich sediments and soils that form in wet environments associated with spring discharge. Micromorphological and geochemical analyses of 25 black mats dating to the Younger Dryas Chronozone (12.9-11.7 ka) and early Holocene were conducted to determine their composition and depositional environment. Samples were collected from Arizona, New Mexico, Texas and Nevada. Micromorphological analyses were conducted on thin sections using polarized and blue fluorescent light. These analyses determined that black mats contain humic acids, fine (5-20 μm) plant fragments, diatoms, phytoliths, and gastropods. The dominant type of organic matter in black mats is derived from herbaceous plants, contradicting previous studies that supported algal or charcoal sources. Differences in the micromorphological characteristics of the samples revealed that black mats formed as three different types, organic horizons, moist soils and, ponded sediments, depending on their topographic position in relation to the water table. The microscopic evidence found in black mats supports the presence of widespread wet environments in Nevada and Arizona during the Younger Dryas Chronozone, clearly indicating a sustained period of greater effective moisture, optimal for spring discharge and black mat formation.

Evaluation of various isotherm models, and metal sorption potential of cyanobacterial mats in single and multi-metal systems.

PubMed

Kumar, Dhananjay; Pandey, Lalit K; Gaur, J P

2010-12-01

Isotherm curves for the biosorption of Cu(II), Cd(II) and Pb(II) by the biomass of five different cyanobacterial mats (Mat # 1-5) showed concave shape and plateau. Suitability of ten different isotherm models was evaluated for the equilibrium modeling of these isotherm curves, however, only the Toth model was found appropriate. Mat # 2, dominated by Phormidium sp., was identified as an excellent metal biosorbent because: (i) the Toth estimated maximum biosorption capacity (mmol g(-1)) of Mat # 2 for Pb(II) (1.028), Cu(II) (0.696) and Cd(II) (0.549) was the highest among the tested mats and compares favourably with Langmuir estimated metal sorption capacity of many seaweeds, regarded as the best metal biosorbents, (ii) Na+, K+ and Ca2+ did not substantially inhibit the biosorption of the test metals, (iii) and total metal sorption ability of Mat # 2 increased or remained unaffected in binary and ternary metal systems. Copyright © 2010 Elsevier B.V. All rights reserved.

Anoxic carbon flux in photosynthetic microbial mats as revealed by metatranscriptomics [Anoxic carbon flux in photosynthetic microbial mats as revealed by metatranscriptomics and NanoSIMS.

DOE PAGES

Burow, Luke C.; Woebken, Dagmar; Marshall, Ian PG; ...

2012-11-29

Photosynthetic microbial mats possess extraordinary phylogenetic and functional diversity that makes linking specific pathways with individual microbial populations a daunting task. Close metabolic and spatial relationships between Cyanobacteria and Chloroflexi have previously been observed in diverse microbial mats. Here in this paper, we report that an expressed metabolic pathway for the anoxic catabolism of photosynthate involving Cyanobacteria and Chloroflexi in microbial mats can be reconstructed through metatranscriptomic sequencing of mats collected at Elkhorn Slough, Monterey Bay, CA, USA. In this reconstruction, Microcoleus spp., the most abundant cyanobacterial group in the mats, ferment photosynthate to organic acids, CO 2 and Hmore » 2 through multiple pathways, and an uncultivated lineage of the Chloroflexi take up these organic acids to store carbon as polyhydroxyalkanoates. The metabolic reconstruction is consistent with metabolite measurements and single cell microbial imaging with fluorescence in situ hybridization and NanoSIMS.« less

Anoxic carbon flux in photosynthetic microbial mats as revealed by metatranscriptomics [Anoxic carbon flux in photosynthetic microbial mats as revealed by metatranscriptomics and NanoSIMS.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burow, Luke C.; Woebken, Dagmar; Marshall, Ian PG

Photosynthetic microbial mats possess extraordinary phylogenetic and functional diversity that makes linking specific pathways with individual microbial populations a daunting task. Close metabolic and spatial relationships between Cyanobacteria and Chloroflexi have previously been observed in diverse microbial mats. Here in this paper, we report that an expressed metabolic pathway for the anoxic catabolism of photosynthate involving Cyanobacteria and Chloroflexi in microbial mats can be reconstructed through metatranscriptomic sequencing of mats collected at Elkhorn Slough, Monterey Bay, CA, USA. In this reconstruction, Microcoleus spp., the most abundant cyanobacterial group in the mats, ferment photosynthate to organic acids, CO 2 and Hmore » 2 through multiple pathways, and an uncultivated lineage of the Chloroflexi take up these organic acids to store carbon as polyhydroxyalkanoates. The metabolic reconstruction is consistent with metabolite measurements and single cell microbial imaging with fluorescence in situ hybridization and NanoSIMS.« less

Enhancement of the in-plane shear properties of carbon fiber composites containing carbon nanotube mats

NASA Astrophysics Data System (ADS)

Kim, Hansang

2015-01-01

The in-plane shear property of carbon fiber laminates is one of the most important structural features of aerospace and marine structures. Fiber-matrix debonding caused by in-plane shear loading is the major failure mode of carbon fiber composites because of the stress concentration at the interfaces. In this study, carbon nanotube mats (CNT mat) were incorporated in two different types of carbon fiber composites. For the case of woven fabric composites, mechanical interlocking between the CNTs and the carbon fibers increased resistance to shear failure. However, not much improvement was observed for the prepreg composites as a result of incorporation of the CNT mats. The reinforcement mechanism of the CNT mat layer was investigated by a fractographic study using scanning electron microscopy. In addition, the CNT mat was functionalized by three different methods and the effectiveness of the functionalization methods was determined and the most appropriate functionalization method for the CNT mat was air oxidation.

Medication assisted treatment in US drug courts: results from a nationwide survey of availability, barriers and attitudes.

PubMed

Matusow, Harlan; Dickman, Samuel L; Rich, Josiah D; Fong, Chunki; Dumont, Dora M; Hardin, Carolyn; Marlowe, Douglas; Rosenblum, Andrew

2013-01-01

Drug treatment courts are an increasingly important tool in reducing the census of those incarcerated for non-violent drug offenses; medication assisted treatment (MAT) is proven to be an effective treatment for opioid addiction. However, little is known about the availability of and barriers to MAT provision for opioid-addicted people under drug court jurisdiction. Using an online survey, we assessed availability, barriers, and need for MAT (especially agonist medication) for opioid addiction in drug courts. Ninety-eight percent reported opioid-addicted participants, and 47% offered agonist medication (56% for all MAT including naltrexone). Barriers included cost and court policy. Responses revealed significant uncertainty, especially among non-MAT providing courts. Political, judicial and administrative opposition appear to affect MAT's inconsistent use and availability in drug court settings. These data suggest that a substantial, targeted educational initiative is needed to increase awareness of the treatment and criminal justice benefits of MAT in the drug courts. Copyright © 2013 Elsevier Inc. All rights reserved.

Evaluation of gallic acid loaded zein sub-micron electrospun fibre mats as novel active packaging materials.

PubMed

Neo, Yun Ping; Swift, Simon; Ray, Sudip; Gizdavic-Nikolaidis, Marija; Jin, Jianyong; Perera, Conrad O

2013-12-01

The applicability of gallic acid loaded zein (Ze-GA) electrospun fibre mats towards potential active food packaging material was evaluated. The surface chemistry of the electrospun fibre mats was determined using X-ray photon spectroscopy (XPS). The electrospun fibre mats showed low water activity and whitish colour. Thermogravimetric analysis (TGA) and Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy revealed the stability of the fibre mats over time. The Ze-GA fibre mats displayed similar rapid release profiles, with Ze-GA 20% exhibiting the fastest release rate in water as compared to the others. Gallic acid diffuses from the electrospun fibres in a Fickian diffusion manner and the data obtained exhibited a better fit to Higuchi model. L929 fibroblast cells were cultured on the electrospun fibres to demonstrate the absence of cytotoxicity. Overall, the Ze-GA fibre mats demonstrated antibacterial activity and properties consistent with those considered desirable for active packaging material in the food industry. Copyright © 2013 Elsevier Ltd. All rights reserved.

Altered pupillary light reflex in PACAP receptor 1-deficient mice.

PubMed

Engelund, Anna; Fahrenkrug, Jan; Harrison, Adrian; Luuk, Hendrik; Hannibal, Jens

2012-05-09

The pupillary light reflex (PLR) is regulated by the classical photoreceptors, rods and cones, and by intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment melanopsin. IpRGCs receive input from rods and cones and project to the olivary pretectal nucleus (OPN), which is the primary visual center involved in PLR. Mice lacking either the classical photoreceptors or melanopsin exhibit some changes in PLR, whereas the reflex is completely lost in mice deficient of all three photoreceptors. The neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) is co-stored with melanopsin in ipRGCs and mediates light signaling to the brain via the specific PACAP receptor 1 (PAC1R). Here, we examined the occurrence of PACAP and PAC1R in the mouse OPN, and studied if lack of PAC1R affected the PLR. PACAP-immunoreactive nerve fibers were shown in the mouse OPN, and by in situ hybridization histochemistry, we demonstrated the presence of PAC1R mRNA. Mice lacking PAC1R exhibited a significantly attenuated PLR compared to wild type mice upon light stimulation, and the difference became more pronounced as light intensity was increased. Our findings accord well with observations of the PLR in the melanopsin-deficient mouse. We conclude that PACAP/PAC1R signaling is involved in the sustained phase of the PLR at high irradiances. Copyright © 2012 Elsevier B.V. All rights reserved.

A role for cryptochromes in sleep regulation.

PubMed

Wisor, Jonathan P; O'Hara, Bruce F; Terao, Akira; Selby, Chris P; Kilduff, Thomas S; Sancar, Aziz; Edgar, Dale M; Franken, Paul

2002-12-20

The cryptochrome 1 and 2 genes (cry1 and cry2) are necessary for the generation of circadian rhythms, as mice lacking both of these genes (cry1,2-/-) lack circadian rhythms. We studied sleep in cry1,2-/- mice under baseline conditions as well as under conditions of constant darkness and enforced wakefulness to determine whether cryptochromes influence sleep regulatory processes. Under all three conditions, cry1,2-/- mice exhibit the hallmarks of high non-REM sleep (NREMS) drive (i.e., increases in NREMS time, NREMS consolidation, and EEG delta power during NREMS). This unexpected phenotype was associated with elevated brain mRNA levels of period 1 and 2 (per1,2), and albumin d-binding protein (dbp), which are known to be transcriptionally inhibited by CRY1,2. To further examine the relationship between circadian genes and sleep homeostasis, we examined wild type mice and rats following sleep deprivation and found increased levels of per1,2 mRNA and decreased levels of dbp mRNA specifically in the cerebral cortex; these changes subsided with recovery sleep. The expression of per3, cry1,2, clock, npas2, bmal1, and casein-kinase-1epsilon did not change with sleep deprivation. These results indicate that mice lacking cryptochromes are not simply a genetic model of circadian arrhythmicity in rodents and functionally implicate cryptochromes in the homeostatic regulation of sleep.

Thermoelectric Properties of Poly(3-Hexylthiophene) Nanofiber Mat with a Large Void Fraction.

PubMed

Hiura, Shogo; Okada, Naoki; Wakui, Junma; Narita, Hikari; Kanehashi, Shinji; Shimomura, Takeshi

2017-04-28

The thermoelectric properties of a poly(3-hexylthiophene) (P3HT) nanofiber mat which has higher crystallinity-and thus exhibits larger carrier mobility-than a non-fibrous P3HT film, were investigated. No significant difference was observed in the maximum values of the power factor between the P3HT nanofiber mat and the P3HT film. However, the thermal conductivity of the nanofiber mat was less than half that of the film despite having almost the same electrical conductivity. This higher thermoelectric property of the nanofiber mat than the film is attributed to the existence of highly effective conducting pathways and a large void fraction, and the result means that the nanofiber mat was a good candidate for use as a thermoelectric material.

The Role of Neuropeptide Y (NPY) in Uncontrolled Alcohol Drinking and Relapse Behavior Resulting from Exposure to Stressful Events

DTIC Science & Technology

2011-01-01

effects of stressors on excessive and uncontrolled drinking and relapse-like drinking. We proposed to use foot-shock as the stressor to elicit increase...did significantly increase deprivation-induced relapse-like drinking, and that this effect was more robust in mutant mice lacking the NPY Y1R. Thus...ethanol consumption using a models of excessive uncontrolled drinking, and mutant mice lacking NPY or the Y1R were more sensitive to the effects of

Targeting Peripheral-Derived Regulatory T Cells as a Means of Enhancing Immune Responses Directed against Prostate Cancer

DTIC Science & Technology

2016-08-01

TRAMP transgenic mice) that lack or preferentially generate pTregs (TRAMP+ mice bred onto Lck-cre; Klf2fl/fl and Smurf1-/- backgrounds, respectively...We have successfully generated TRAMP+; Lck-cre; Klf2fl/fl and TRAMP+; Smurf1-/- breeding lines, which will provide us with the necessary animals to...Aim 1: Determine how blocking pTreg production impacts PCa Major Task 1: Score tumors in TRAMP cohorts that contain or lack pTregs. The breeding

Collaboration of Antibody and Inflammation in Clearance of Rabies Virus from the Central Nervous System

PubMed Central

Hooper, D. Craig; Morimoto, Kinjiro; Bette, Michael; Weihe, Eberhard; Koprowski, Hilary; Dietzschold, Bernhard

1998-01-01

To investigate the involvement of various cellular and humoral aspects of immunity in the clearance of rabies virus from the central nervous system, (CNS), we studied the development of clinical signs and virus clearance from the CNS in knockout mice lacking either B and T cells, CD8+ cytotoxic T cells, B cells, alpha/beta interferon (IFN-α/β) receptors, IFN-γ receptors, or complement components C3 and C4. Following intranasal infection with the attenuated rabies virus CVS-F3, normal adult mice of different genetic backgrounds developed a transient disease characterized by loss of body weight and appetite depression which peaked at 13 days postinfection (p.i.). While these animals had completely recovered by day 21 p.i., mice lacking either B and T cells or B cells alone developed a progressive disease and succumbed to infection. Mice lacking either CD8+ T cells, IFN receptors, or complement components C3 and C4 showed no significant differences in the development of clinical signs by comparison with intact counterparts having the same genetic background. However, while infectious virus and viral RNA could be detected in normal control mice only until day 8 p.i., in all of the gene knockout mice studied except those lacking C3 and C4, virus infection persisted through day 21 p.i. Analysis of rabies virus-specific antibody production together with histological assessment of brain inflammation in infected animals revealed that clearance of CVS-F3 by 21 days p.i. correlated with both a strong inflammatory response in the CNS early in the infection (day 8 p.i.), and the rapid (day 10 p.i.) production of significant levels of virus-neutralizing antibody (VNA). These studies confirm that rabies VNA is an absolute requirement for clearance of an established rabies virus infection. However, for the latter to occur in a timely fashion, collaboration between VNA and inflammatory mechanisms is necessary. PMID:9557653

The selective metabotropic glutamate 2/3 receptor agonist MGS0028 reverses psychomotor abnormalities and recognition memory deficits in mice lacking the pituitary adenylate cyclase-activating polypeptide.

PubMed

Ago, Yukio; Hiramatsu, Naoki; Ishihama, Toshihiro; Hazama, Keisuke; Hayata-Takano, Atsuko; Shibasaki, Yasuhiro; Shintani, Norihito; Hashimoto, Hitoshi; Kawasaki, Toshiyuki; Onoe, Hirotaka; Chaki, Shigeyuki; Nakazato, Atsuro; Baba, Akemichi; Takuma, Kazuhiro; Matsuda, Toshio

2013-02-01

Previous studies suggest that metabotropic glutamate 2/3 receptors are involved in psychiatric disorders. In this study, we examined the effects of the selective metabotropic glutamate 2/3 (mGlu2/3) receptor agonist MGS0028 on behavioral abnormalities in mice lacking the pituitary adenylate cyclase-activating polypeptide (PACAP), an experimental model of psychiatric disorders such as schizophrenia and attention-deficit/hyperactivity disorder. We found that PACAP-deficient mice showed impairments in the novel object recognition test and these impairments were improved by MGS0028 (0.1 mg/kg). Similarly, MGS0028 improved hyperactivity and jumping behaviors, but did not reverse increased immobility times in the forced swim test in PACAP-deficient mice. These results suggest that MGS0028 may be a potential, novel treatment for psychiatric disorders.

Photosynthetic Microbial Mats are Exemplary Sources of Diverse Biosignatures (Invited)

NASA Astrophysics Data System (ADS)

Des Marais, D. J.; Jahnke, L. L.

2013-12-01

Marine cyanobacterial microbial mats are widespread, compact, self-contained ecosystems that create diverse biosignatures and have an ancient fossil record. Within the mats, oxygenic photosynthesis provides organic substrates and O2 to the community. Both the absorption and scattering of light change the intensity and spectral composition of incident radiation as it penetrates a mat. Some phototrophs utilize infrared light near the base of the photic zone. A mat's upper layers can become highly reduced and sulfidic at night. Counteracting gradients of O2 and sulfide shape the chemical environment and provide daily-contrasting microenvironments separated on a scale of a few mm. Radiation hazards (UV, etc.), O2 and sulfide toxicity elicit motility and other physiological responses. This combination of benefits and hazards of light, O2 and sulfide promotes the allocation of various essential mat processes between light and dark periods and to various depths in the mat. Associated nonphotosynthetic communities, including anaerobes, strongly influence many of the ecosystem's overall characteristics, and their processes affect any biosignatures that enter the fossil record. A biosignature is an object, substance and/or pattern whose origin specifically requires a biological agent. The value of a biosignature depends not only on the probability of life creating it, but also on the improbability of nonbiological processes producing it. Microbial mats create biosignatures that identify particular groups of organisms and also reveal attributes of the mat ecosystem. For example, branched hydrocarbons and pigments can be diagnostic of cyanobacteria and other phototrophic bacteria, and isoprenoids can indicate particular groups of archea. Assemblages of lipid biosignatures change with depth due to changes in microbial populations and diagenetic transformations of organic matter. The 13C/12C values of organic matter and carbonates reflect isotopic discrimination by particular microorganisms as well as networks of C flow within mats; thus they offer insights about community structure. For example, relative 13C/12C values of individual lipid biosignatures can indicate trophic relationships between key groups of microorganisms. Mat microenvironments can affect the stability of authigenic minerals and alter the chemical compositions and crystal forms of carbonate, sulfate and metal oxide minerals. Interactions between low molecular weight organic compounds and sulfides in mat pore waters can produce alkyl sulfide gases. Processes associated with these physically coherent biofilms can trap and bind detrital grains, enhance mineral precipitation or dissolution, and stabilize sediment surfaces. Accordingly mats can create distinctive sedimentary fabrics and structures. Stromatolites are the most ancient, widespread examples of such fabrics and structures. Thus photosynthetic microbial mats create diverse biosignatures that, when preserved in the geologic record, can help to identify the former presence of key populations of microorganisms and reveal key processes that occurred within ancient mats as well as the interactions between those ecosystems and their environment.

University of California San Francisco (UCSF-2): Gene Expression Profiling of Normal Mouse Skin, Hras WT and Hras -/- | Office of Cancer Genomics

Cancer.gov

University of California San Francisco (UCSF-2): Gene Expression Profiling of Normal Mouse Skin, Hras WT and Hras -/- This data set contains the transcriptional profiles of 20 dorsal skin samples from eight-week-old mice. Mice were generated by crossing FVB/N to Mus spretus mice to generate F1 mice, and then crossing F1 mice back to the FVB/N strain. 10  FVB/N mice lacking Hras1 (aka HrasKO, Hras-/-) and 10  FVB/N mice with wild-type Hras1 were generated. Read the abstract.

Antibody response is required for protection from Theiler's virus-induced encephalitis in C57BL/6 mice in the absence of CD8{sup +} T cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, B.-S.; Palma, Joann P.; Lyman, Michael A.

2005-09-15

Intracerebral infection of susceptible mice with Theiler's murine encephalomyelitis virus (TMEV) induces immune-mediated demyelinating disease and this system serves as a relevant infectious model for human multiple sclerosis. It was previously shown that {beta}{sub 2}M-deficient C57BL/6 mice lacking functional CD8{sup +} T cells display increased viral persistence and enhanced susceptibility to TMEV-induced demyelination, and yet the majority of mice are free of clinical signs. To understand the mechanisms involved in this general resistance of C57BL/6 mice in the absence of CTL responses, mice ({mu}MT) deficient in the B-cell compartment lacking membrane IgM molecules were treated with anti-CD8 antibody and thenmore » infected with TMEV. Although little difference in the proliferative responses of peripheral T cells to UV-inactivated TMEV and the resistance to demyelinating disease was observed between virus-infected {mu}MT and control B6 mice, the levels of CD4{sup +} T cells were higher in the CNS of {mu}MT mice. However, after treatment with anti-CD8 antibody, 100% of the mice displayed clinical gray matter disease and prolonged viral persistence in {mu}MT mice, while only 10% of B6 mice showed clinical symptoms and very low viral persistence. Transfusion of sera from TMEV-infected B6 mice into anti-CD8 antibody-treated {mu}MT mice partially restored resistance to virus-induced encephalitis. These results indicate that the early anti-viral antibody response is also important in the protection from TMEV-induced encephalitis particularly in the absence of CD8{sup +} T cells.« less

Contributions of ectomycorrhizal fungal mats to forest soil respiration

Treesearch

C. Phillips; L.A. Kluber; J.P. Martin; B.A. Caldwell; B.J. Bond

2012-01-01

Distinct aggregations of fungal hyphae and rhizomorphs, or “mats”, formed by some genera of ectomycorrhizal (EcM) fungi are common features of soils in coniferous forests of the Pacific Northwest. We measured in situ respiration rates of Piloderma mats and neighboring non-mat soils in an old-growth Douglas-fir forest in western Oregon to investigate whether there was...

Flakeboard thickness swelling. Part I, Stress relaxation in a flakeboard mat

Treesearch

R. L. Geimer; J. H. Kwon; J. Bolton

1998-01-01

The steam injection schedule best suited for dimensionally stabilizing a flake mat is one in which steam treatment is initiated before the press is closed and is continued at least until the mat attains target thickness. Experiments showed that resinless mats treated with 20 sec of steam at 600 kPa had maximum thickness swelling of 205% compared to 350% for resinless...

17 CFR 249.1300T - Form MA-T, for temporary registration as a municipal advisor, and for amendments to, and...

Code of Federal Regulations, 2014 CFR

2014-04-01

... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Form MA-T, for temporary... Information Regarding Certain Natural Persons § 249.1300T Form MA-T, for temporary registration as a municipal... Register citations affecting Form MA-T, see the List of CFR Sections Affected, which appears in the Finding...

Exposure to brominated and organophosphate ester flame retardants in U.S. childcare environments: Effect of removal of flame-retarded nap mats on indoor levels.

PubMed

Stubbings, W A; Schreder, E D; Thomas, M B; Romanak, K; Venier, M; Salamova, A

2018-07-01

We assessed exposure to 39 brominated and 16 organophosphate ester flame retardants (FRs) from both dust and indoor air at seven childcare centres in Seattle, USA, and investigated the importance of nap mats as a source of these chemicals. Many childcare centres serving young children use polyurethane foam mats for the children's naptime. Until recently, the vast majority of these mats sold in the United States contained flame-retarded polyurethane foam to meet California Technical Bulletin 117 (TB117) requirements. With the 2013 update of TB117, allowing manufacturers to meet flammability standards without adding FRs to filling materials, FR-free nap mats have become widely available. We conducted an intervention study by actively switching out FR-treated nap mats with FR-free nap mats and measuring FR levels in indoor air and dust before and after the switch-out. The predominant FRs found in dust and indoor air were 2-ethylhexyl tetrabromobenzoate (EHTBB) and tris(1-chloro-2-propyl) phosphate (TCIPP), respectively. Nap mat samples analysed from four of the six centres contained a Firemaster ® mixture, while one mat was predominantly treated with tris(1,3-dichloroisopropyl) phosphate (TDCIPP) and the other contained no detectable target FRs. After replacement, there was a significant decrease (p = 0.03-0.09) in median dust concentrations for bis(2-ethylhexyl) tetrabromophthalate (BEHTBP), EHTBB, tris(4-butylphenyl) phosphate (TBPP), and TDCIPP with reductions of 90%, 79%, 65%, and 42%, respectively. These findings suggest that the nap mats were an important source of these FRs to dust in the investigated childcare environments and that a campaign of swapping out flame-retarded mats for FR-free ones would reduce exposure to these chemicals. While calculated exposure estimates to the investigated FRs via inhalation, dust ingestion, and dermal absorption were below established reference dose values, they are likely underestimated when considering the toddlers' direct contact to the mats and personal cloud effects. Copyright © 2018 Elsevier Ltd. All rights reserved.

Contribution by Macroalgal Mats to Primary Production of a Shallow Embayment Under High and Low Nitrogen-loading Rates

NASA Astrophysics Data System (ADS)

Peckol, P.; Rivers, J. S.

1996-09-01

The limits on primary production in areas undergoing eutrophication may be set by indirect effects of nitrogen loading, i.e. decreasing irradiances, associated with proliferating opportunistic algae. Using in situphoton flux density (PFD) availability estimates within unattached algal mats and photosynthetic parameters determined from photosynthesis vs.irradiance (P vs.I) curves generated for the dominant components of mat assemblages, Cladophora vagabundaand Gracilaria tikvahiae, seasonal net mat production rate for estuaries (Waquoit Bay, Massachusetts, U.S.A.) receiving high (Childs River) and low (Sage Lot Pond) N-loading rates were determined. Although abundance of C. vagabundawas 2× greater than G. tikvahiae, the former species contributed only about 50% of total mat productivity, due largely to rapid light attenuation within the dense algal mat. While mat production was low and similar at both sides during winter (≈0·35 g C m -2 day -1), for other seasons, the net mat daytime productivity at Childs River, the N-loaded site, was 2·5× higher than rates determined for Sage Lot Pond. Although annual net daytime production at Childs River (1094 g C m -2 year -1) was comparable to estimates for other algal mat assemblages in eutrophic systems, primary production of the Waquoit Bay system was found to become self-limiting as available PFD controls maximum productivity. In photosynthetically inactive portions of the algal mat, carbon release was estimated from tissue-loss measurements at 0·14 g C m -2 day -1for C. vagabundaand 0·05 g C m -2 day -1for G. tikvahiae. Annual in situC release of 73 g C m -2is ≈20% of annual net mat production (fixed carbon not respired by algae) in this embayment. Although both estuaries showed net autotrophy year round (Pg:R>1), the high metabolic cost of a large, inactive mat resulted in lower Pg:R ratios at Childs Rivers than at Sage Lot Pond, particularly during the summer period of peak production. Thus, it is predicted that the Waquoit Bay system will experience an overall decline in Pg:R ratios and consequent increase in anoxic events as eutrophication continues.

Benthic Marine Cyanobacterial Mat Ecosystems: Biogeochemistry and Biomarkers

NASA Technical Reports Server (NTRS)

DesMarais, David J.; DeVincenzi, Donald (Technical Monitor)

2001-01-01

Cyanobacterial mats are complete ecosystems that can include processes of primary production, diagenesis and lithification. Light sustains oxygenic photosynthesis, which in turn provides energy, organic matter and oxygen to the community. Due to both absorption and scattering phenomena, incident light is transformed with depth in the mat, both in intensity and spectral composition. Mobile photo synthesizers optimize their position with respect to this light gradient. When photosynthesis ceases at night, the upper layers of the mat become reduced and sulfidic. Counteracting gradients of oxygen and sulfide combine to provide daily-contrasting environments separated on a scale of a few mm. The functional complexity of mats, coupled with the highly proximal and ordered spatial arrangement of biota, offers the potential for a staggering number of interactions. At a minimum, the products of each functional group of microorganisms affect the other groups both positively and negatively. For example, cyanobacteria generate organic matter (potential substrates) but also oxygen (a toxin for many anaerobes). Anaerobic activity recycles nutrients to the photosynthesizers but also generates potentially toxic sulfide. The combination of benefits and hazards of light, oxygen and sulfide promotes the allocation of the various essential mat processes between light and dark periods, and to various depths in the mat. Observations of mats have produced numerous surprises. For example, obligately anaerobic processes can occur in the presence of abundant oxygen, highly reduced gases are produced in the presence of abundant sulfate, meiofauna thrive at high sulfide concentrations, and the mats' constituent populations respond to environmental changes in complex ways. While photosynthetic bacteria dominate the biomass and productivity of the mat, nonphotosynthetic, anaerobic processes constitute the ultimate biological filter on the ecosystem's emergent biosignatures, including those sedimentary textures, organic compounds, and minerals that enter the fossil record. The ability of cyanobacterial mats to channel abundant solar energy into the creation and maintenance of complex structures and processes has created a multitude of consequences, both for sedimentation and for the early evolution of our biosphere.

Passive Mixing Capabilities of Micro- and Nanofibres When Used in Microfluidic Systems.

PubMed

Matlock-Colangelo, Lauren; Colangelo, Nicholas W; Fenzl, Christoph; Frey, Margaret W; Baeumner, Antje J

2016-08-05

Nanofibres are increasingly being used in the field of bioanalytics due to their large surface-area-to-volume ratios and easy-to-functionalize surfaces. To date, nanofibres have been studied as effective filters, concentrators, and immobilization matrices within microfluidic devices. In addition, they are frequently used as optical and electrochemical transduction materials. In this work, we demonstrate that electrospun nanofibre mats cause appreciable passive mixing and therefore provide dual functionality when incorporated within microfluidic systems. Specifically, electrospun nanofibre mats were integrated into Y-shaped poly(methyl methacrylate) microchannels and the degree of mixing was quantified using fluorescence microscopy and ImageJ analysis. The degree of mixing afforded in relationship to fibre diameter, mat height, and mat length was studied. We observed that the most mixing was caused by small diameter PVA nanofibres (450-550 nm in diameter), producing up to 71% mixing at the microchannel outlet, compared to up to 51% with polystyrene microfibres (0.8-2.7 μm in diameter) and 29% mixing in control channels containing no fibres. The mixing afforded by the PVA nanofibres is caused by significant inhomogeneity in pore size and distribution leading to percolation. As expected, within all the studies, fluid mixing increased with fibre mat height, which corresponds to the vertical space of the microchannel occupied by the fibre mats. Doubling the height of the fibre mat led to an average increase in mixing of 14% for the PVA nanofibres and 8% for the PS microfibres. Overall, mixing was independent of the length of the fibre mat used (3-10 mm), suggesting that most mixing occurs as fluid enters and exits the fibre mat. The mixing effects observed within the fibre mats were comparable to or better than many passive mixers reported in literature. Since the nanofibre mats can be further functionalized to couple analyte concentration, immobilization, and detection with enhanced fluid mixing, they are a promising nanomaterial providing dual-functionality within lab-on-a-chip devices.

Passive Mixing Capabilities of Micro- and Nanofibres When Used in Microfluidic Systems

PubMed Central

Matlock-Colangelo, Lauren; Colangelo, Nicholas W.; Fenzl, Christoph; Frey, Margaret W.; Baeumner, Antje J.

2016-01-01

Nanofibres are increasingly being used in the field of bioanalytics due to their large surface-area-to-volume ratios and easy-to-functionalize surfaces. To date, nanofibres have been studied as effective filters, concentrators, and immobilization matrices within microfluidic devices. In addition, they are frequently used as optical and electrochemical transduction materials. In this work, we demonstrate that electrospun nanofibre mats cause appreciable passive mixing and therefore provide dual functionality when incorporated within microfluidic systems. Specifically, electrospun nanofibre mats were integrated into Y-shaped poly(methyl methacrylate) microchannels and the degree of mixing was quantified using fluorescence microscopy and ImageJ analysis. The degree of mixing afforded in relationship to fibre diameter, mat height, and mat length was studied. We observed that the most mixing was caused by small diameter PVA nanofibres (450–550 nm in diameter), producing up to 71% mixing at the microchannel outlet, compared to up to 51% with polystyrene microfibres (0.8–2.7 μm in diameter) and 29% mixing in control channels containing no fibres. The mixing afforded by the PVA nanofibres is caused by significant inhomogeneity in pore size and distribution leading to percolation. As expected, within all the studies, fluid mixing increased with fibre mat height, which corresponds to the vertical space of the microchannel occupied by the fibre mats. Doubling the height of the fibre mat led to an average increase in mixing of 14% for the PVA nanofibres and 8% for the PS microfibres. Overall, mixing was independent of the length of the fibre mat used (3–10 mm), suggesting that most mixing occurs as fluid enters and exits the fibre mat. The mixing effects observed within the fibre mats were comparable to or better than many passive mixers reported in literature. Since the nanofibre mats can be further functionalized to couple analyte concentration, immobilization, and detection with enhanced fluid mixing, they are a promising nanomaterial providing dual-functionality within lab-on-a-chip devices. PMID:27527184

Mean Annual Temperature Drives Microbial Nitrogen Cycling and Fine Root Nutrient Foraging Across a Tropical Montane Wet Forest Elevation Gradient

NASA Astrophysics Data System (ADS)

Pierre, S.; Litton, C. L. M.; Giardina, C. P.; Sparks, J. P.; Groffman, P. M.; Hewson, I.; Fahey, T. J.

2017-12-01

Mean annual temperature (MAT) is positively correlated with rates of primary production and carbon (C) turnover in forests globally, but the underlying biotic drivers of these relationships remain poorly resolved. We hypothesized that (1) MAT increases nitrifier abundance and thereby nitrate (NO-) bioavailability in soils and (2) increased NO- bioavailability reduces fine root nitrogen (N) demand. We used an ecologically well-constrained natural elevation gradient (13˚C -18˚C) in a tropical wet motane forest on the Island of Hawaii to study to role of MAT in situ. Our previous work showed that MAT drives increased soil NO- bioavailability in situ (r²=0.79, P=0.003), and indicated that the abundance of ammonia oxidizing archaea is strongly and positively correlated with MAT in situ (r²=0.34, P<0.001; Pierre et. al. 2017). Using fertilized fine root ingrowth cores (+N, +P, +N+P, control) across the same MAT gradient, we found that increasing MAT and bulk soil NO- bioavailability produced a significant negative fine root response to the +N+P treatment (P=0.023), and no response to other fertilization treatments. Increasing MAT and soil NO- bioavailability led to increased percent arbuscular mycorrhizal (AM) colonization of fine roots (r²=0.43, P=0.004), but no treatment effect on AM colonization was observed. Our results suggest that N and P generally co-limit fine root foraging across the gradient, while higher MAT and bulk soil NO- bioavailability interact to reduce fine root foraging effort. Further, higher MAT and greater N fertility in soils may reduce the C limitation of AM fungal colonization. We conclude that MAT drives N-rich conditions, which allow for lower N foraging effort, but greater C investment in P acquisition through AM fine root colonization.

Susceptibility of a potential animal model for pathological anxiety to chronic mild stress.

PubMed

Salomons, Amber R; Kortleve, Tessa; Reinders, Niels R; Kirchhoff, Susanne; Arndt, Saskia S; Ohl, Frauke

2010-06-19

When anxiety-related behaviour in animals appears to lack adaptive value, it might be defined as pathological. Adaptive behaviour can be assessed for example by changes in behavioural responses over time, i.e. habituation. Thus, non-adaptive anxiety would be reflected by a lack of habituation. Recently, we found that 129P3/J mice are characterised by non-adaptive avoidance behaviour after repeated test exposure. The present study was aimed at investigating the sensitivity of the behavioural profile of these animals to exposure to a chronic mild stress (CMS) paradigm followed by repeated exposure to the modified hole board test. If the behavioural profile of 129P3/J mice mirrors pathological anxiety, their behavioural habituation under repeated test exposure conditions should be affected by CMS treatment. The results confirm the profound lack of habituation with respect to anxiety-related behaviour in both control and CMS treated mice. Additionally, CMS treated animals revealed a lower exploratory behaviour, reduced locomotor activity and increased arousal-related behaviour over time when compared to control individuals, proving an extension of their impaired habituation behaviour. Although no effects of CMS treatment on plasma corticosterone levels were found, higher immediate early gene expression in the bed nucleus of the stria terminalis and the ventrolateral periaqueductal grey in CMS treated mice indicated that 129P3/J mice are susceptible to the negative effects of CMS treatment at both the behavioural and the functional level. These results support the hypothesis that 129P3/J mice might be an interesting model for pathological anxiety. Copyright 2010 Elsevier B.V. All rights reserved.

Deletion of Lkb1 in pro-opiomelanocortin neurons impairs peripheral glucose homeostasis in mice.

PubMed

Claret, Marc; Smith, Mark A; Knauf, Claude; Al-Qassab, Hind; Woods, Angela; Heslegrave, Amanda; Piipari, Kaisa; Emmanuel, Julian J; Colom, André; Valet, Philippe; Cani, Patrice D; Begum, Ghazala; White, Anne; Mucket, Phillip; Peters, Marco; Mizuno, Keiko; Batterham, Rachel L; Giese, K Peter; Ashworth, Alan; Burcelin, Remy; Ashford, Michael L; Carling, David; Withers, Dominic J

2011-03-01

AMP-activated protein kinase (AMPK) signaling acts as a sensor of nutrients and hormones in the hypothalamus, thereby regulating whole-body energy homeostasis. Deletion of Ampkα2 in pro-opiomelanocortin (POMC) neurons causes obesity and defective neuronal glucose sensing. LKB1, the Peutz-Jeghers syndrome gene product, and Ca(2+)-calmodulin-dependent protein kinase kinase β (CaMKKβ) are key upstream activators of AMPK. This study aimed to determine their role in POMC neurons upon energy and glucose homeostasis regulation. Mice lacking either Camkkβ or Lkb1 in POMC neurons were generated, and physiological, electrophysiological, and molecular biology studies were performed. Deletion of Camkkβ in POMC neurons does not alter energy homeostasis or glucose metabolism. In contrast, female mice lacking Lkb1 in POMC neurons (PomcLkb1KO) display glucose intolerance, insulin resistance, impaired suppression of hepatic glucose production, and altered expression of hepatic metabolic genes. The underlying cellular defect in PomcLkb1KO mice involves a reduction in melanocortin tone caused by decreased α-melanocyte-stimulating hormone secretion. However, Lkb1-deficient POMC neurons showed normal glucose sensing, and body weight was unchanged in PomcLkb1KO mice. Our findings demonstrate that LKB1 in hypothalamic POMC neurons plays a key role in the central regulation of peripheral glucose metabolism but not body-weight control. This phenotype contrasts with that seen in mice lacking AMPK in POMC neurons with defects in body-weight regulation but not glucose homeostasis, which suggests that LKB1 plays additional functions distinct from activating AMPK in POMC neurons.

The rewarding action of acute cocaine is reduced in β-endorphin deficient but not in μ opioid receptor knockout mice.

PubMed

Nguyen, Alexander T; Marquez, Paul; Hamid, Abdul; Kieffer, Brigitte; Friedman, Theodore C; Lutfy, Kabirullah

2012-07-05

We have previously shown that β-endorphin plays a functional role in the rewarding effect of acute cocaine. Considering that β-endorphin has high affinity for the μ opioid receptor, we determined the role of this receptor in the rewarding action of acute cocaine. For comparison, we assessed the role of the μ opioid receptor in the rewarding effect of acute morphine. We also examined the effect of intracerebroventricular (i.c.v.) administration of β-funaltrexamine (β-FNA), an irreversible μ opioid receptor antagonist, on the rewarding action of acute cocaine as well as that of morphine. Using the conditioned place preference (CPP) paradigm as an animal model of reward, we first assessed the rewarding action of cocaine in mice lacking β-endorphin or the μ opioid receptor and their respective wild-type littermates/controls. Mice were tested for preconditioning place preference on day 1, conditioned once daily with saline/cocaine (30mg/kg, i.p.) or cocaine/saline on days 2 and 3, and then tested for postconditioning place preference on day 4. We next studied the rewarding action of acute morphine in μ knockout mice and their wild-type controls. The CPP was induced by single alternate-day saline/morphine (10mg/kg, s.c.) or morphine/saline conditioning. We finally determined the effect of β-FNA on CPP induced by cocaine or morphine in wild-type mice, in which mice were treated with saline or β-FNA (9ug/3μl; i.c.v.) a day prior to the preconditioning test day. Our results revealed that morphine induced a robust CPP in wild-type mice but not in mice lacking the μ opioid receptor or in wild-type mice treated with β-FNA. In contrast, cocaine induced CPP in μ knockout mice as well as in wild-type mice treated with β-FNA. On the other hand, cocaine failed to induce CPP in mice lacking β-endorphin. These results illustrate that β-endorphin is essential for the rewarding action of acute cocaine, but the μ opioid receptor may not mediate the regulatory action of endogenous β-endorphin. Copyright © 2012 Elsevier B.V. All rights reserved.

Reactivation of a cryptobiotic stream ecosystem in the McMurdo Dry Valleys, Antarctica: A long-term geomorphological experiment

USGS Publications Warehouse

McKnight, Diane M.; Tate, C.M.; Andrews, E.D.; Niyogi, D.K.; Cozzetto, K.; Welch, K.; Lyons, W.B.; Capone, D.G.

2007-01-01

The McMurdo Dry Valleys of Antarctica contain many glacial meltwater streams that flow for 6 to 12??weeks during the austral summer and link the glaciers to the lakes on the valley floors. Dry valley streams gain solutes longitudinally through weathering reactions and microbial processes occurring in the hyporheic zone. Some streams have thriving cyanobacterial mats. In streams with regular summer flow, the mats are freeze-dried through the winter and begin photosynthesizing with the onset of flow. To evaluate the longer term persistence of cyanobacterial mats, we diverted flow to an abandoned channel, which had not received substantial flow for approximately two decades. Monitoring of specific conductance showed that for the first 3??years after the diversion, the solute concentrations were greater in the reactivated channel than in most other dry valley streams. We observed that cyanobacterial mats became abundant in the reactivated channel within a week, indicating that the mats had been preserved in a cryptobiotic state in the channel. Over the next several years, these mats had high rates of productivity and nitrogen fixation compared to mats from other streams. Experiments in which mats from the reactivated channel and another stream were incubated in water from both of the streams indicated that the greater solute concentrations in the reactivated channel stimulated net primary productivity of mats from both streams. These stream-scale experimental results indicate that the cryptobiotic preservation of cyanobacterial mats in abandoned channels in the dry valleys allows for rapid response of these stream ecosystems to climatic and geomorphological change, similar to other arid zone stream ecosystems. ?? 2006 Elsevier B.V. All rights reserved.

Preferences of dairy cows for three stall surface materials with small amounts of bedding.

PubMed

Norring, M; Manninen, E; de Passillé, A M; Rushen, J; Saloniemi, H

2010-01-01

Farmers' concerns about the economy, cost of labor, and hygiene have resulted in reduced use of organic bedding in stalls for dairy cows; however, the reduced use of organic bedding possibly impairs cow comfort. The effects of different stall surface materials were evaluated in an unheated building in which only a small amount of bedding was used. The lying time and preferences of 18 cows using 3 stall surface materials (concrete, soft rubber mat, and sand) were compared. All materials were lightly bedded with a small amount of straw, and the amount of straw added to each stall was measured. The cows only had access to stalls of one surface type while their lying time was observed. Lying times were longest on the rubber mats compared with other surfaces (rubber mat 768; concrete 727; sand 707+/-16 min/d). In a preference test, cows had access to 2 of the 3 types of stalls for 10 d and their stall preference was measured. Cows preferred stalls with rubber mats to stalls with a concrete floor (median 73 vs. 18 from a total of 160 observations per day; interquartile range was 27 and 12, respectively), but showed no preference for sand stalls compared with stalls with a concrete floor or with rubber mats. More straw was needed on sand stalls compared with concrete or mat (638+/-13 g/d on sand, 468+/-10 g/d on concrete, and 464+/-8 g/d on rubber mats). Lying times on bedded mats indicated that mats were comfortable for the cows. If availability or cost of bedding material requires limiting the amount of bedding used, rubber mats may help maintain cow comfort. Copyright 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Ecosystem carbon storage does not vary with mean annual temperature in Hawaiian tropical montane wet forests.

PubMed

Selmants, Paul C; Litton, Creighton M; Giardina, Christian P; Asner, Gregory P

2014-09-01

Theory and experiment agree that climate warming will increase carbon fluxes between terrestrial ecosystems and the atmosphere. The effect of this increased exchange on terrestrial carbon storage is less predictable, with important implications for potential feedbacks to the climate system. We quantified how increased mean annual temperature (MAT) affects ecosystem carbon storage in above- and belowground live biomass and detritus across a well-constrained 5.2 °C MAT gradient in tropical montane wet forests on the Island of Hawaii. This gradient does not systematically vary in biotic or abiotic factors other than MAT (i.e. dominant vegetation, substrate type and age, soil water balance, and disturbance history), allowing us to isolate the impact of MAT on ecosystem carbon storage. Live biomass carbon did not vary predictably as a function of MAT, while detrital carbon declined by ~14 Mg of carbon ha(-1) for each 1 °C rise in temperature - a trend driven entirely by coarse woody debris and litter. The largest detrital pool, soil organic carbon, was the most stable with MAT and averaged 48% of total ecosystem carbon across the MAT gradient. Total ecosystem carbon did not vary significantly with MAT, and the distribution of ecosystem carbon between live biomass and detritus remained relatively constant across the MAT gradient at ~44% and ~56%, respectively. These findings suggest that in the absence of alterations to precipitation or disturbance regimes, the size and distribution of carbon pools in tropical montane wet forests will be less sensitive to rising MAT than predicted by ecosystem models. This article also provides needed detail on how individual carbon pools and ecosystem-level carbon storage will respond to future warming. © 2014 John Wiley & Sons Ltd.

Evolution of Mat Strength from the Paleoarchean to the Modern: A Record of Evolving Microbial Communities?

NASA Astrophysics Data System (ADS)

Tice, M.; Pope, M.; Thornton, D.

2011-12-01

Fossil microbial mats, i.e. surface-attached communities of benthic microorganisms, form the most extensive record of life on Earth. Qualitatively changing mat morphologies from 3.43-0.56-billion-years-ago may reflect the evolution of microorganism communities or changing environmental conditions. However, mat morphogenesis is not well understood or easily quantifiable, making interpretation of the mat record difficult. We show that microbial mat cohesion increased from ~1 Pa to ~13 Pa at 2.7-billion-years-ago (Ga), and has remained high for most of the rest of Earth history. This initial increase may represent an early increase in the productivity of mat communities, a change in the composition of extracellular polymeric substances (EPS) produced by mat-formers, or a change in the composition of seawater affecting EPS strength. The appearance of early high-strength communities was coincident with the appearance of voids representing gas bubbles in the apices of conical stromatolites; together, these changes may record the emergence of productive mat communities dominated by oxygenic cyanobacteria. The earliest high-strength communities, like early bubble-forming conical stromatolites, grew in low-energy environments. The appearance of high-strength communities in shallow-water environments starting 2.63-2.52 Ga coincided with the appearance of the first barrier reef complexes. We hypothesize that the first oxygenic cyanobacteria were most competitive with anoxygenic phototrophs in diffusion-limited environments. As the cyanobacteria became more proficient at oxygenic photosynthesis, they eventually outcompeted anoxygenic phototrophs in higher-energy environments. Competition with higher strength seaweed and grazing by metazoans has displaced mat communities from essentially all modern high-energy niches.

Novel poly(ε-caprolactone)/gelatin wound dressings prepared by emulsion electrospinning with controlled release capacity of Ketoprofen anti-inflammatory drug.

PubMed

Basar, A O; Castro, S; Torres-Giner, S; Lagaron, J M; Turkoglu Sasmazel, H

2017-12-01

In the present study, a single and binary Ketoprofen-loaded mats of ultrathin fibers were developed by electrospinning and their physical properties and drug release capacity was analyzed. The single mat was prepared by solution electrospinning of poly(ε-caprolactone) (PCL) with Ketoprofen at a weight ratio of 5wt%. This Ketoprofen-containing PCL solution was also used as the oil phase in a 7:3 (wt/wt) emulsion with gelatin dissolved in acidified water. The resultant stable oil-in-water (O/W) emulsion of PCL-in-gelatin, also containing Ketoprofen at 5wt%, was electrospun to produce the binary mat. Cross-linking process was performed by means of glutaraldehyde vapor on the electrospun binary mat to prevent dissolution of the hydrophilic gelatin phase. The performed characterization indicated that Ketoprofen was successfully embedded in the single and binary electrospun mats, i.e. PCL and PCL/gelatin, and both mats showed high hydrophobicity but poor thermal resistance. In vitro release studies interestingly revealed that, in comparison to the single PCL electrospun mat, the binary PCL/gelatin mat significantly hindered Ketoprofen burst release and exhibited a sustained release capacity of the drug for up to 4days. In addition, the electrospun Ketoprofen-loaded mats showed enhanced attachment and proliferation of L929 mouse fibroblast cells, presenting the binary mat the highest cell growth yield due to its improved porosity. The here-developed electrospun materials clearly show a great deal of potential as novel wound dressings with an outstanding controlled capacity to release drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

Freeze-thaw revival of rotifers and algae in a desiccated, high-elevation (5500 meters) microbial mat, high Andes, Perú.

PubMed

Schmidt, S K; Darcy, J L; Sommers, Pacifica; Gunawan, Eva; Knelman, J E; Yager, Karina

2017-05-01

This is the first study of the highest elevation cyanobacteria-dominated microbial mat yet described. The desiccated mat was sampled in 2010 from an ephemeral rock pool at 5500 m above sea level in the Cordillera Vilcanota of southern Perú. After being frozen for 6 years at -20 °C in the lab, pieces of the mat were sequenced to fully characterize both the 16 and 18S microbial communities and experiments were conducted to determine if organisms in the mat could revive and become active under the extreme freeze-thaw conditions that these mats experience in the field. Sequencing revealed an unexpectedly diverse, multi-trophic microbial community with 16S OTU richness comparable to similar, seasonally desiccated mats from the Dry Valleys of Antarctica and low elevation sites in the Atacama Desert region. The bacterial community of the mat was dominated by phototrophs in the Cyanobacteria (Nostoc) and the Rhodospirillales, whereas the eukaryotic community was dominated by predators such as bdelloid rotifers (Philodinidae). Microcosm experiments showed that bdelloid rotifers in the mat were able to come out of dormancy and actively forage even under realistic field conditions (diurnal temperature fluctuations of -12 °C at night to + 27 °C during the day), and after being frozen for 6 years. Our results broaden our understanding of the diversity of life in periodically desiccated, high-elevation habitats and demonstrate that extreme freeze-thaw cycles per se are not a major factor limiting the development of at least some members of these unique microbial mat systems.

The type of mat (Contact vs. Photocell) affects vertical jump height estimated from flight time.

PubMed

García-López, Juan; Morante, Juan C; Ogueta-Alday, Ana; Rodríguez-Marroyo, Jose A

2013-04-01

The purposes of this study were to analyze the validity and reliability of 2 photocell mats and to probe the possible influence of the type of mat (contact vs. photocell) on vertical jump height estimated from flight time. In 2 separate studies, 89 and 92 physical students performed 3 countermovement jumps that were simultaneously registered by a Force Plate (gold standard method), 2 photocell mats (SportJump System Pro and ErgoJump Plus), and a contact mat (SportJump-v1.0). The first study showed that the 2 photocell mats underestimated the vertical jump height (1.3 ± 0.2 cm and 5.9 ± 5.2 cm, respectively), but only SportJump System Pro showed a high correlation with the Force Plate (r = 0.999 and 0.676, respectively) and good intraday reliability (coefficient of variation = 2.98 and 15.94%, intraclass correlation coefficients = 0.95-0.97 and 0.45-0.57, respectively). The second study demonstrated a strong correlation (r = 0.994) between the 2 technologies (contact vs. photocell mats) with differences in vertical jump height of 2.0 ± 0.8 cm (95% confidence interval = 1.9-2.1 cm), which depended on both flight time and subjects' body mass. In conclusion, SportJump System Pro was a valid and reliable device. The new devices to measure vertical jump height from flight time should be validated. The type of mat (contact vs. photocell) affected approximately 6% the vertical jump height (approximately 2 cm in this study), which should be considered in further studies. The use of validated photocell mats instead of the contact mats was recommended.

Impulsive Choice in Mice Lacking Paternal Expression of Grb10 Suggests Intragenomic Conflict in Behavior

PubMed Central

Dent, Claire L.; Humby, Trevor; Lewis, Katie; Ward, Andrew; Fischer-Colbrie, Reiner; Wilkinson, Lawrence S.; Wilkins, Jon F.; Isles, Anthony R.

2018-01-01

Imprinted genes are expressed from one parental allele only as a consequence of epigenetic events that take place in the mammalian germ line and are thought to have evolved through intragenomic conflict between parental alleles. We demonstrate, for the first time, oppositional effects of imprinted genes on brain and behavior. Specifically, we show that mice lacking paternal Grb10 make fewer impulsive choices, with no dissociable effects on a separate measure of impulsive action. Taken together with previous work showing that mice lacking maternal Nesp55 make more impulsive choices, this suggests that impulsive choice behavior is a substrate for the action of genomic imprinting. Moreover, the contrasting effect of these two genes suggests that impulsive choices are subject to intragenomic conflict and that maternal and paternal interests pull this behavior in opposite directions. Finally, these data may also indicate that an imbalance in expression of imprinted genes contributes to pathological conditions such as gambling and drug addiction, where impulsive behavior becomes maladaptive. PMID:29563147

Methylmercury enters an aquatic food web through acidophilic microbial mats in Yellowstone National Park, Wyoming

USGS Publications Warehouse

Boyd, E.S.; King, S.; Tomberlin, J.K.; Nordstrom, D. Kirk; Krabbenhoft, D.P.; Barkay, T.; Geesey, G.G.

2009-01-01

Summary Microbial mats are a visible and abundant life form inhabiting the extreme environments in Yellowstone National Park (YNP), WY, USA. Little is known of their role in food webs that exist in the Park's geothermal habitats. Eukaryotic green algae associated with a phototrophic green/purple Zygogonium microbial mat community that inhabits low-temperature regions of acidic (pH ??? 3.0) thermal springs were found to serve as a food source for stratiomyid (Diptera: Stratiomyidae) larvae. Mercury in spring source water was taken up and concentrated by the mat biomass. Monomethylmercury compounds (MeHg +), while undetectable or near the detection limit (0.025 ng l -1) in the source water of the springs, was present at concentrations of 4-7 ng g-1 dry weight of mat biomass. Detection of MeHg + in tracheal tissue of larvae grazing the mat suggests that MeHg+ enters this geothermal food web through the phototrophic microbial mat community. The concentration of MeHg+ was two to five times higher in larval tissue than mat biomass indicating MeHg+ biomagnification occurred between primary producer and primary consumer trophic levels. The Zygogonium mat community and stratiomyid larvae may also play a role in the transfer of MeHg+ to species in the food web whose range extends beyond a particular geothermal feature of YNP. ?? 2008 The Authors. Journal compilation ?? 2008 Society for Applied Microbiology and Blackwell Publishing Ltd.

Sway Area and Velocity Correlated With MobileMat Balance Error Scoring System (BESS) Scores.

PubMed

Caccese, Jaclyn B; Buckley, Thomas A; Kaminski, Thomas W

2016-08-01

The Balance Error Scoring System (BESS) is often used for sport-related concussion balance assessment. However, moderate intratester and intertester reliability may cause low initial sensitivity, suggesting that a more objective balance assessment method is needed. The MobileMat BESS was designed for objective BESS scoring, but the outcome measures must be validated with reliable balance measures. Thus, the purpose of this investigation was to compare MobileMat BESS scores to linear and nonlinear measures of balance. Eighty-eight healthy collegiate student-athletes (age: 20.0 ± 1.4 y, height: 177.7 ± 10.7 cm, mass: 74.8 ± 13.7 kg) completed the MobileMat BESS. MobileMat BESS scores were compared with 95% area, sway velocity, approximate entropy, and sample entropy. MobileMat BESS scores were significantly correlated with 95% area for single-leg (r = .332) and tandem firm (r = .474), and double-leg foam (r = .660); and with sway velocity for single-leg (r = .406) and tandem firm (r = .601), and double-leg (r = .575) and single-leg foam (r = .434). MobileMat BESS scores were not correlated with approximate or sample entropy. MobileMat BESS scores were low to moderately correlated with linear measures, suggesting the ability to identify changes in the center of mass-center of pressure relationship, but not higher-order processing associated with nonlinear measures. These results suggest that the MobileMat BESS may be a clinically-useful tool that provides objective linear balance measures.

PA15 Beer mat chat.

PubMed

Hazelwood, Mark A; Patterson, Rebecca M

2015-04-01

Storytelling/remembrance can the reduce isolation of recently (and less recently) bereaved people, and are beneficial to participants. Traditional rituals and approaches which supported storytelling/remembrance are declining in Scotland. Pubs are hubs of social interaction and storytelling, especially for men. To explore the acceptability of beer mats in pubs as a prompt to storytelling and remembrance of people who have died, and to promote To Absent Friends, a peoples' festival of storytelling and remembrance. 5 mats were designed - each had a carefully selected quotation or piece of trivia relating to loss or remembrance, plus a web link to www.toabsentfriends.org.uk. 20,000 mats were made available to order. Feedback regarding acceptability was elicited through conversation with bar tenders, direct observation and a questionnaire dispatched with some orders. A press release was issued. The mats were generally viewed as being acceptable. A local brewer distributed Approximately 15,000 mats to pubs across Edinburgh. The main Edinburgh newspaper ran a prominent article about the mats, the To Absent Friends Festival and the value of greater openness about death and dying. Beer mats are an acceptable way of introducing reflection on loss, grief and mortality into pubs. More research is needed to establish the effectiveness of the mats in prompting storytelling and remembrance. © 2015, Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Timescales of Growth Response of Microbial Mats to Environmental Change in an Ice-Covered Antarctic Lake

PubMed Central

Hawes, Ian; Sumner, Dawn Y.; Andersen, Dale T.; Jungblut, Anne D.; Mackey, Tyler J.

2013-01-01

Lake Vanda is a perennially ice-covered, closed-basin lake in the McMurdo Dry Valleys, Antarctica. Laminated photosynthetic microbial mats cover the floor of the lake from below the ice cover to >40 m depth. In recent decades, the water level of Lake Vanda has been rising, creating a “natural experiment” on development of mat communities on newly flooded substrates and the response of deeper mats to declining irradiance. Mats in recently flooded depths accumulate one lamina (~0.3 mm) per year and accrue ~0.18 µg chlorophyll-a cm−2 y−1. As they increase in thickness, vertical zonation becomes evident, with the upper 2-4 laminae forming an orange-brown zone, rich in myxoxanthophyll and dominated by intertwined Leptolyngbya trichomes. Below this, up to six phycobilin-rich green/pink-pigmented laminae form a subsurface zone, inhabited by Leptolyngbya, Oscillatoria and Phormidium morphotypes. Laminae continued to increase in thickness for several years after burial, and PAM fluorometry indicated photosynthetic potential in all pigmented laminae. At depths that have been submerged for >40 years, mats showed similar internal zonation and formed complex pinnacle structures that were only beginning to appear in shallower mats. Chlorophyll-a did not change over time and these mats appear to represent resource-limited “climax” communities. Acclimation of microbial mats to changing environmental conditions is a slow process, and our data show how legacy effects of past change persist into the modern community structure. PMID:24832656

Timescales of growth response of microbial mats to environmental change in an ice-covered antarctic lake.

PubMed

Hawes, Ian; Sumner, Dawn Y; Andersen, Dale T; Jungblut, Anne D; Mackey, Tyler J

2013-01-25

Lake Vanda is a perennially ice-covered, closed-basin lake in the McMurdo Dry Valleys, Antarctica. Laminated photosynthetic microbial mats cover the floor of the lake from below the ice cover to >40 m depth. In recent decades, the water level of Lake Vanda has been rising, creating a "natural experiment" on development of mat communities on newly flooded substrates and the response of deeper mats to declining irradiance. Mats in recently flooded depths accumulate one lamina (~0.3 mm) per year and accrue ~0.18 µg chlorophyll-a cm-2 y-1. As they increase in thickness, vertical zonation becomes evident, with the upper 2-4 laminae forming an orange-brown zone, rich in myxoxanthophyll and dominated by intertwined Leptolyngbya trichomes. Below this, up to six phycobilin-rich green/pink-pigmented laminae form a subsurface zone, inhabited by Leptolyngbya, Oscillatoria and Phormidium morphotypes. Laminae continued to increase in thickness for several years after burial, and PAM fluorometry indicated photosynthetic potential in all pigmented laminae. At depths that have been submerged for >40 years, mats showed similar internal zonation and formed complex pinnacle structures that were only beginning to appear in shallower mats. Chlorophyll-a did not change over time and these mats appear to represent resource-limited "climax" communities. Acclimation of microbial mats to changing environmental conditions is a slow process, and our data show how legacy effects of past change persist into the modern community structure.

Effect of salinity changes on the bacterial diversity, photosynthesis and oxygen consumption of cyanobacterial mats from an intertidal flat of the Arabian Gulf.

PubMed

Abed, Raeid M M; Kohls, Katharina; de Beer, Dirk

2007-06-01

The effects of salinity fluctuation on bacterial diversity, rates of gross photosynthesis (GP) and oxygen consumption in the light (OCL) and in the dark (OCD) were investigated in three submerged cyanobacterial mats from a transect on an intertidal flat. The transect ran 1 km inland from the low water mark along an increasingly extreme habitat with respect to salinity. The response of GP, OCL and OCD in each sample to various salinities (65 per thousand, 100 per thousand, 150 per thousand and 200 per thousand) were compared. The obtained sequences and the number of unique operational taxonomic units showed clear differences in the mats' bacterial composition. While cyanobacteria decreased from the lower to the upper tidal mat, other bacterial groups such as Chloroflexus and Cytophaga/Flavobacteria/Bacteriodetes showed an opposite pattern with the highest dominance in the middle and upper tidal mats respectively. Gross photosynthesis and OCL at the ambient salinities of the mats decreased from the lower to the upper tidal zone. All mats, regardless of their tidal location, exhibited a decrease in areal GP, OCL and OCD rates at salinities > 100 per thousand. The extent of inhibition of these processes at higher salinities suggests an increase in salt adaptation of the mats microorganisms with distance from the low water line. We conclude that the resilience of microbial mats towards different salinity regimes on intertidal flats is accompanied by adjustment of the diversity and function of their microbial communities.

Hepatic gluconeogenesis is enhanced by phosphatidic acid which remains uninhibited by insulin in lipodystrophic Agpat2-/- mice.

PubMed

Sankella, Shireesha; Garg, Abhimanyu; Horton, Jay D; Agarwal, Anil K

2014-02-21

In this study we examined the role of phosphatidic acid (PA) in hepatic glucose production (HGP) and development of hepatic insulin resistance in mice that lack 1-acylglycerol-3-phosphate O-acyltransferase 2 (AGPAT2). Liver lysophosphatidic acid and PA levels were increased ∼2- and ∼5-fold, respectively, in male Agpat2(-/-) mice compared with wild type mice. In the absence of AGPAT2, the liver can synthesize PAs by activating diacylglycerol kinase or phospholipase D, both of which were elevated in the livers of Agpat2(-/-) mice. We found that PAs C16:0/18:1 and C18:1/20:4 enhanced HGP in primary WT hepatocytes, an effect that was further enhanced in primary hepatocytes from Agpat2(-/-) mice. Lysophosphatidic acids C16:0 and C18:1 failed to increase HGP in primary hepatocytes. The activation of HGP was accompanied by an up-regulation of the key gluconeogenic enzymes glucose-6-phosphatase and phosphoenolpyruvate carboxykinase. This activation was suppressed by insulin in the WT primary hepatocytes but not in the Agpat2(-/-) primary hepatocytes. Thus, the lack of normal insulin signaling in Agpat2(-/-) livers allows unrestricted PA-induced gluconeogenesis significantly contributing to the development of hyperglycemia in these mice.

Adenosine A3 receptors regulate heart rate, motor activity and body temperature

PubMed Central

Yang, Jiangning; Wang, Yingqing; Garcia-Roves, Pablo; Björnholm, Marie; Fredholm, Bertil B.

2010-01-01

Aim We wanted to examine the phenotype of mice that lack the adenosine A3 receptor (A3R). Methods We examined the heart rate, body temperature and locomotion continuously by telemetry over several days. In addition the effect of the adenosine analogue R - N6- phenylisopropyl-adenosine (R-PIA) was examined. In addition, we examined heat production and food intake. Results We found that the marked diurnal variation in activity, heart rate and body temperature, with markedly higher values at night than during day time, was reduced in the A3R knockout mice. Surprisingly, the reduction in heart rate, activity and body temperature seen after injection of R-PIA in wild type mice was virtually eliminated in the A3R knock-out mice. The marked reduction in activity was associated with a decreased heat production, as expected. However, the A3R knock-out mice, surprisingly, had a higher food intake but no difference in body weight compared to wild type mice. Conclusions The mice lacking adenosine A3 receptors exhibit a surprisingly clear phenotype with changes in e.g. diurnal rhythm and temperature regulation. Whether these effects are due to a physiological role of A3 receptors in these processes or if they represent a role in development remains to be elucidated. PMID:20121716

Improve Data Mining and Knowledge Discovery Through the Use of MatLab

NASA Technical Reports Server (NTRS)

Shaykhian, Gholam Ali; Martin, Dawn (Elliott); Beil, Robert

2011-01-01

Data mining is widely used to mine business, engineering, and scientific data. Data mining uses pattern based queries, searches, or other analyses of one or more electronic databases/datasets in order to discover or locate a predictive pattern or anomaly indicative of system failure, criminal or terrorist activity, etc. There are various algorithms, techniques and methods used to mine data; including neural networks, genetic algorithms, decision trees, nearest neighbor method, rule induction association analysis, slice and dice, segmentation, and clustering. These algorithms, techniques and methods used to detect patterns in a dataset, have been used in the development of numerous open source and commercially available products and technology for data mining. Data mining is best realized when latent information in a large quantity of data stored is discovered. No one technique solves all data mining problems; challenges are to select algorithms or methods appropriate to strengthen data/text mining and trending within given datasets. In recent years, throughout industry, academia and government agencies, thousands of data systems have been designed and tailored to serve specific engineering and business needs. Many of these systems use databases with relational algebra and structured query language to categorize and retrieve data. In these systems, data analyses are limited and require prior explicit knowledge of metadata and database relations; lacking exploratory data mining and discoveries of latent information. This presentation introduces MatLab(R) (MATrix LABoratory), an engineering and scientific data analyses tool to perform data mining. MatLab was originally intended to perform purely numerical calculations (a glorified calculator). Now, in addition to having hundreds of mathematical functions, it is a programming language with hundreds built in standard functions and numerous available toolboxes. MatLab's ease of data processing, visualization and its enormous availability of built in functionalities and toolboxes make it suitable to perform numerical computations and simulations as well as a data mining tool. Engineers and scientists can take advantage of the readily available functions/toolboxes to gain wider insight in their perspective data mining experiments.

Improve Data Mining and Knowledge Discovery through the use of MatLab

NASA Technical Reports Server (NTRS)

Shaykahian, Gholan Ali; Martin, Dawn Elliott; Beil, Robert

2011-01-01

Data mining is widely used to mine business, engineering, and scientific data. Data mining uses pattern based queries, searches, or other analyses of one or more electronic databases/datasets in order to discover or locate a predictive pattern or anomaly indicative of system failure, criminal or terrorist activity, etc. There are various algorithms, techniques and methods used to mine data; including neural networks, genetic algorithms, decision trees, nearest neighbor method, rule induction association analysis, slice and dice, segmentation, and clustering. These algorithms, techniques and methods used to detect patterns in a dataset, have been used in the development of numerous open source and commercially available products and technology for data mining. Data mining is best realized when latent information in a large quantity of data stored is discovered. No one technique solves all data mining problems; challenges are to select algorithms or methods appropriate to strengthen data/text mining and trending within given datasets. In recent years, throughout industry, academia and government agencies, thousands of data systems have been designed and tailored to serve specific engineering and business needs. Many of these systems use databases with relational algebra and structured query language to categorize and retrieve data. In these systems, data analyses are limited and require prior explicit knowledge of metadata and database relations; lacking exploratory data mining and discoveries of latent information. This presentation introduces MatLab(TradeMark)(MATrix LABoratory), an engineering and scientific data analyses tool to perform data mining. MatLab was originally intended to perform purely numerical calculations (a glorified calculator). Now, in addition to having hundreds of mathematical functions, it is a programming language with hundreds built in standard functions and numerous available toolboxes. MatLab's ease of data processing, visualization and its enormous availability of built in functionalities and toolboxes make it suitable to perform numerical computations and simulations as well as a data mining tool. Engineers and scientists can take advantage of the readily available functions/toolboxes to gain wider insight in their perspective data mining experiments.

Knowledge of and concerns about long-acting reversible contraception among women in medication-assisted treatment for opioid use disorder.

PubMed

Matusiewicz, Alexis K; Melbostad, Heidi S; Heil, Sarah H

2017-11-01

To assess interest in, concerns about and knowledge of long-acting reversible contraceptives (LARC) among women in medication-assisted treatment (MAT) for opioid use disorder who were at risk for unintended pregnancy. Women in MAT completed a survey on contraceptive use, attitudes and knowledge, including LARC methods, as part of eligibility screening for an ongoing trial evaluating family planning interventions for this population. Eighty-three women at risk for unintended pregnancy completed the survey, and a subset of 51 completed supplemental questions about implants. All participants had heard of IUDs and 75/83 (90%) had heard of implants, but only 34/83 (41%) and 14/51 (27%) reported being likely to use IUDs and implants, respectively. Thirty-five women reported they were unlikely to use IUDs, with 29/35 (83%) citing unspecified "other reasons" for this position and 24/35 (69%) endorsing concerns about side effects. Seventeen women reported they were unlikely to use implants, with 8/17 (47%) citing "other reasons" and 9/17 (53%) and 10/17 (59%) reporting concerns about insertion and removal, respectively. Participants reported they knew "a little" about LARCs, but only their knowledge of implants was limited. Only 50/83 (60%) participants were aware of the superior effectiveness of IUDs and 26/51 (51%) were aware of the superior effectiveness of implants relative to other reversible methods. Participants reported relatively low interest in LARCs. Many women had unspecified reasons for not using LARCs. Participants also lacked information about LARC safety and effectiveness, especially with regard to implants. Women in medication-assisted treatment for opioid use disorder are at high risk of unintended pregnancy, yet contraceptive use is low and use of less effective methods is common. Women in MAT may benefit from efforts to increase knowledge about implants and assuage concerns about their insertion and removal as well as more general efforts to improve knowledge about the relative efficacy of LARCs. Many women in MAT endorsed unspecified "other reasons" for not using LARCs, which should be explored further. Copyright © 2017 Elsevier Inc. All rights reserved.

Development of Chloroplast and Nuclear DNA Markers for Chinese Oaks (Quercus Subgenus Quercus) and Assessment of Their Utility as DNA Barcodes

PubMed Central

Yang, Jia; Vázquez, Lucía; Chen, Xiaodan; Li, Huimin; Zhang, Hao; Liu, Zhanlin; Zhao, Guifang

2017-01-01

Chloroplast DNA (cpDNA) is frequently used for species demography, evolution, and species discrimination of plants. However, the lack of efficient and universal markers often brings particular challenges for genetic studies across different plant groups. In this study, chloroplast genomes from two closely related species (Quercus rubra and Castanea mollissima) in Fagaceae were compared to explore universal cpDNA markers for the Chinese oak species in Quercus subgenus Quercus, a diverse species group without sufficient molecular differentiation. With the comparison, nine and 14 plastid markers were selected as barcoding and phylogeographic candidates for the Chinese oaks. Five (psbA-trnH, matK-trnK, ycf3-trnS, matK, and ycf1) of the nine plastid candidate barcodes, with the addition of newly designed ITS and a single-copy nuclear gene (SAP), were then tested on 35 Chinese oak species employing four different barcoding approaches (genetic distance-, BLAST-, character-, and tree-based methods). The four methods showed different species identification powers with character-based method performing the best. Of the seven barcodes tested, a barcoding gap was absent in all of them across the Chinese oaks, while ITS and psbA-trnH provided the highest species resolution (30.30%) with the character- and BLAST-based methods, respectively. The six-marker combination (psbA-trnH + matK-trnK + matK + ycf1 + ITS + SAP) showed the best species resolution (84.85%) using the character-based method for barcoding the Chinese oaks. The barcoding results provided additional implications for taxonomy of the Chinese oaks in subg. Quercus, basically identifying three major infrageneric clades of the Chinese oaks (corresponding to Groups Quercus, Cerris, and Ilex) referenced to previous phylogenetic classification of Quercus. While the morphology-based allocations proposed for the Chinese oaks in subg. Quercus were challenged. A low variation rate of the chloroplast genome, and complex speciation patterns involving incomplete lineage sorting, interspecific hybridization and introgression, possibly have negative impacts on the species assignment and phylogeny of oak species. PMID:28579999

Mast cells play no role in the pathogenesis of postoperative ileus induced by intestinal manipulation.

PubMed

Gomez-Pinilla, Pedro J; Farro, Giovanna; Di Giovangiulio, Martina; Stakenborg, Nathalie; Némethova, Andrea; de Vries, Annick; Liston, Adrian; Feyerabend, Thorsten B; Rodewald, Hans-Reimer; Rodewald, Hans-Reimwer; Boeckxstaens, Guy E; Matteoli, Gianluca

2014-01-01

Intestinal manipulation (IM) during abdominal surgery results in intestinal inflammation leading to hypomotility or ileus. Mast cell activation is thought to play a crucial role in the pathophysiology of postoperative ileus (POI). However, this conclusion was mainly drawn using mast cell-deficient mouse models with abnormal Kit signaling. These mice also lack interstitial cells of Cajal (ICC) resulting in aberrant gastrointestinal motility even prior to surgery, compromising their use as model to study POI. To avoid these experimental weaknesses we took advantage of a newly developed knock-in mouse model, Cpa3(Cre/+) , devoid of mast cells but with intact Kit signaling. The role of mast cells in the development of POI and intestinal inflammation was evaluated assessing gastrointestinal transit and muscularis externa inflammation after IM in two strains of mice lacking mast cells, i.e. Kit(W-sh/W-sh) and Cpa3(Cre/+) mice, and by use of the mast cell stabilizer cromolyn. Kit(W-sh/W-sh) mice lack ICC networks and already revealed significantly delayed gastrointestinal transit even before surgery. IM did not further delay intestinal transit, but induced infiltration of myeloperoxidase positive cells, expression of inflammatory cytokines and recruitment of monocytes and neutrophils into the muscularis externa. On the contrary, Cpa3(Cre/+) mice have a normal network of ICC and normal gastrointestinal. Surprisingly, IM in Cpa3(Cre/+) mice caused delay in gut motility and intestinal inflammation as in wild type littermates mice (Cpa3(+/+) ). Furthermore, treatment with the mast cell inhibitor cromolyn resulted in an inhibition of mast cells without preventing POI. Here, we confirm that IM induced mast cell degranulation. However, our data demonstrate that mast cells are not required for the pathogenesis of POI in mice. Although there might be species differences between mouse and human, our results argue against mast cell inhibitors as a therapeutic approach to shorten POI.

Mast Cells Play No Role in the Pathogenesis of Postoperative Ileus Induced by Intestinal Manipulation

PubMed Central

Gomez-Pinilla, Pedro J.; Farro, Giovanna; Di Giovangiulio, Martina; Stakenborg, Nathalie; Némethova, Andrea; de Vries, Annick; Liston, Adrian; Feyerabend, Thorsten B.; Rodewald, Hans-Reimwer; Boeckxstaens, Guy E.; Matteoli, Gianluca

2014-01-01

Introduction Intestinal manipulation (IM) during abdominal surgery results in intestinal inflammation leading to hypomotility or ileus. Mast cell activation is thought to play a crucial role in the pathophysiology of postoperative ileus (POI). However, this conclusion was mainly drawn using mast cell-deficient mouse models with abnormal Kit signaling. These mice also lack interstitial cells of Cajal (ICC) resulting in aberrant gastrointestinal motility even prior to surgery, compromising their use as model to study POI. To avoid these experimental weaknesses we took advantage of a newly developed knock-in mouse model, Cpa3Cre/+, devoid of mast cells but with intact Kit signaling. Design The role of mast cells in the development of POI and intestinal inflammation was evaluated assessing gastrointestinal transit and muscularis externa inflammation after IM in two strains of mice lacking mast cells, i.e. KitW-sh/W-sh and Cpa3Cre/+ mice, and by use of the mast cell stabilizer cromolyn. Results KitW-sh/W-sh mice lack ICC networks and already revealed significantly delayed gastrointestinal transit even before surgery. IM did not further delay intestinal transit, but induced infiltration of myeloperoxidase positive cells, expression of inflammatory cytokines and recruitment of monocytes and neutrophils into the muscularis externa. On the contrary, Cpa3Cre/+ mice have a normal network of ICC and normal gastrointestinal. Surprisingly, IM in Cpa3Cre/+ mice caused delay in gut motility and intestinal inflammation as in wild type littermates mice (Cpa3+/+). Furthermore, treatment with the mast cell inhibitor cromolyn resulted in an inhibition of mast cells without preventing POI. Conclusions Here, we confirm that IM induced mast cell degranulation. However, our data demonstrate that mast cells are not required for the pathogenesis of POI in mice. Although there might be species differences between mouse and human, our results argue against mast cell inhibitors as a therapeutic approach to shorten POI. PMID:24416383

CD32a antibodies induce thrombocytopenia and type II hypersensitivity reactions in FCGR2A mice

PubMed Central

Robles-Carrillo, Liza; Davila, Monica; Brodie, Meghan; Desai, Hina; Rivera-Amaya, Mildred; Francis, John L.; Amirkhosravi, Ali

2015-01-01

The CD32a immunoglobulin G (IgG) receptor (Fcγ receptor IIa) is a potential therapeutic target for diseases in which IgG immune complexes (ICs) mediate inflammation, such as heparin-induced thrombocytopenia, rheumatoid arthritis, and systemic lupus erythematosus. Monoclonal antibodies (mAbs) are a promising strategy for treating such diseases. However, IV.3, perhaps the best characterized CD32a-blocking mAb, was recently shown to induce anaphylaxis in immunocompromised “3KO” mice. This anaphylactic reaction required a human CD32a transgene because mice lack an equivalent of this gene. The finding that IV.3 induces anaphylaxis in CD32a-transgenic mice was surprising because IV.3 had long been thought to lack the intrinsic capacity to trigger cellular activation via CD32a. Such an anaphylactic reaction would also limit potential therapeutic applications of IV.3. In the present study, we examine the molecular mechanisms by which IV.3 induces anaphylaxis. We now report that IV.3 induces anaphylaxis in immunocompetent CD32a-transgenic “FCGR2A” mice, along with the novel finding that IV.3 and 2 other well-characterized CD32a-blocking mAbs, AT-10 and MDE-8, also induce severe thrombocytopenia in FCGR2A mice. Using recombinant variants of these same mAbs, we show that IgG “Fc” effector function is necessary for the induction of anaphylaxis and thrombocytopenia in FCGR2A mice. Variants of these mAbs lacking the capacity to activate mouse IgG receptors not only failed to induce anaphylaxis or thrombocytopenia, but also very potently protected FCGR2A mice from near lethal doses of IgG ICs. Our findings show that effector-deficient IV.3, AT-10, and MDE-8 are promising candidates for developing therapeutic mAbs to treat CD32a-mediated diseases. PMID:26396093

An Examination of the Role of L-Glutamate and Inosine 5'-Monophosphate in Hedonic Taste-Guided Behavior by Mice Lacking the T1R1 + T1R3 Receptor.

PubMed

Blonde, Ginger D; Spector, Alan C

2017-06-01

The heterodimeric T1R1 + T1R3 receptor is considered critical for normal signaling of L-glutamate and 5'-ribonucleotides in the oral cavity. However, some taste-guided responsiveness remains in mice lacking one subunit of the receptor, suggesting that other receptors are sufficient to support some behaviors. Here, mice lacking both receptor subunits (KO) and wild-type (WT, both n = 13) mice were tested in a battery of behavioral tests. Mice were trained and tested in gustometers with a concentration series of Maltrin-580, a maltodextrin, in a brief-access test (10-s trials) as a positive control. Similar tests followed with monosodium glutamate (MSG) with and without the ribonucleotide inosine 5'-monophosphate (IMP), but always in the presence of the epithelial sodium channel blocker amiloride (A). Brief-access tests were repeated following short-term (30-min) and long-term (48-h) exposures to MSG + A + IMP and were also conducted with sodium gluconate replacing MSG. Finally, progressive ratio tests were conducted with Maltrin-580 or MSG + A + IMP, to assess appetitive behavior while minimizing satiation. Overall, MSG generated little concentration-dependent responding in either food-restricted WT or KO mice, even in combination with IMP. However, KO mice licked less to the amino acid stimuli, a measure of consummatory behavior in the brief-access tests. In contrast, both groups initiated a similar number of trials and had a similar breakpoint in the progressive ratio task, both measures of appetitive (approach) behavior. Collectively, these results suggest that while the T1R1 + T1R3 receptor is necessary for consummatory responding to MSG (+IMP), other receptors are sufficient to maintain appetitive responding to this "umami" stimulus complex in food-restricted mice. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Biliary transport of irinotecan and metabolites in normal and P-glycoprotein-deficient mice.

PubMed

Iyer, Lalitha; Ramírez, Jacqueline; Shepard, Dale R; Bingham, Christopher M; Hossfeld, Dieter-Kurt; Ratain, Mark J; Mayer, Ulrich

2002-04-01

The extensive and unpredictable biliary excretion of CPT-11 and its metabolites, SN-38 and SN-38 glucuronide (SN-38G) may contribute to the wide interpatient variability reported in the disposition and gastrointestinal toxicity of CPT-11. We studied the role of P-glycoprotein (P-gp) in in vivo biliary excretion of CPT-11, SN-38 and SN-38G in mice lacking mdr1-type P-gp [ mdr1a/1b(-/-)] in the presence of the multidrug resistance (MDR) reversal agent, PSC833. Wild-type (Wt) and mdr1a/1b(-/-) mice ( n=3 or 4) were treated intragastrically with PSC833 (50 mg/kg) or vehicle 2 h prior to i.v. CPT-11 dosing (10 mg/kg), and bile samples were collected. P-gp was found to play an important role in CPT-11 biliary excretion, as there was a significant (40%, P<0.05) decrease in its biliary recovery in 90 min in mdr1a/1b(-/-) mice (6.6+/-0.6% dose) compared with Wt mice (11+/-1.2%). This also implied a major role of other undetermined non-P-gp-mediated mechanism(s) for hepatic transport of CPT-11, which was inhibited by PSC833 (1.8+/-0.8% with PSC833, 6.6+/-0.6% without PSC833) in mdr1a/1b(-/-) mice. SN-38 and SN-38G biliary transport was unchanged in mice lacking P-gp after vehicle treatment, indicating a lack of P-gp mediation in their transport. PSC833 significantly reduced (56-89%) SN-38 and SN-38G biliary transport in Wt and mdr1a/1b(-/-) mice, suggesting that PSC833 may be a candidate to modulate biliary excretion of SN-38 with potential use in reducing CPT-11 toxicity.

Therapeutic cloning in individual parkinsonian mice

PubMed Central

Tabar, Viviane; Tomishima, Mark; Panagiotakos, Georgia; Wakayama, Sayaka; Menon, Jayanthi; Chan, Bill; Mizutani, Eiji; Al-Shamy, George; Ohta, Hiroshi; Wakayama, Teruhiko; Studer, Lorenz

2009-01-01

Cell transplantation with embryonic stem (ES) cell progeny requires immunological compatibility with host tissue. ‘Therapeutic cloning’ is a strategy to overcome this limitation by generating nuclear transfer (nt)ES cells that are genetically matched to an individual. Here we establish the feasibility of treating individual mice via therapeutic cloning. Derivation of 187 ntES cell lines from 24 parkinsonian mice, dopaminergic differentiation, and transplantation into individually matched host mice showed therapeutic efficacy and lack of immunological response. PMID:18376409

Impaired olfaction in mice lacking aquaporin-4 water channels

PubMed Central

Lu, Daniel C.; Zhang, Hua; Zador, Zsolt; Verkman, A. S.

2008-01-01

Aquaporin-4 (AQP4) is a water-selective transport protein expressed in glial cells throughout the central nervous system. AQP4 deletion in mice produces alterations in several neuroexcitation phenomena, including hearing, vision, epilepsy, and cortical spreading depression. Here, we report defective olfaction and electroolfactogram responses in AQP4-null mice. Immunofluorescence indicated strong AQP4 expression in supportive cells of the nasal olfactory epithelium. The olfactory epithelium in AQP4-null mice had identical appearance, but did not express AQP4, and had ∼12-fold reduced osmotic water permeability. Behavioral analysis showed greatly impaired olfaction in AQP4-null mice, with latency times of 17 ± 0.7 vs. 55 ± 5 s in wild-type vs. AQP4-null mice in a buried food pellet test, which was confirmed using an olfactory maze test. Electroolfactogram voltage responses to multiple odorants were reduced in AQP4-null mice, with maximal responses to triethylamine of 0.80 ± 0.07 vs. 0.28 ± 0.03 mV. Similar olfaction and electroolfactogram defects were found in outbred (CD1) and inbred (C57/bl6) mouse genetic backgrounds. Our results establish AQP4 as a novel determinant of olfaction, the deficiency of which probably impairs extracellular space K+ buffering in the olfactory epithelium.—Lu, D. C., Zhang, H., Zador, Z., Verkman, A. S. Impaired olfaction in mice lacking aquaporin-4 water channels. PMID:18511552

Alimentary tract innervation deficits and dysfunction in mice lacking GDNF family receptor alpha2.

PubMed

Rossi, Jari; Herzig, Karl-Heinz; Võikar, Vootele; Hiltunen, Païvi H; Segerstråle, Mikael; Airaksinen, Matti S

2003-09-01

Subsets of parasympathetic and enteric neurons require neurturin signaling via glial cell line-derived neurotrophic factor family receptor alpha2 (GFRalpha2) for development and target innervation. Why GFRalpha2-deficient (Gfra2-/-) mice grow poorly has remained unclear. Here, we analyzed several factors that could contribute to the growth retardation. Neurturin mRNA was localized in the gut circular muscle. GFRalpha2 protein was expressed in most substance P-containing myenteric neurons, in most intrapancreatic neurons, and in surrounding glial cells. In the Gfra2-/- mice, density of substance P-containing myenteric ganglion cells and nerve bundles in the myenteric ganglion cell layer was significantly reduced, and transit of test material through small intestine was 25% slower compared to wild-type mice. Importantly, the knockout mice had approximately 80% fewer intrapancreatic neurons, severely impaired cholinergic innervation of the exocrine but not the endocrine pancreas, and increased fecal fat content. Vagally mediated stimulation of pancreatic secretion by 2-deoxy-glucose in vivo was virtually abolished. Retarded growth of the Gfra2-/- mice was accompanied by reduced fat mass and elevated basal metabolic rate. Moreover, the knockout mice drank more water than wild-type controls, and wet-mash feeding resulted in partial growth rescue. Taken together, the results suggest that the growth retardation in mice lacking GFRalpha2 is largely due to impaired salivary and pancreatic secretion and intestinal dysmotility.

Phylogenetic Evidence for the Existence of Novel Thermophilic Bacteria in Hot Spring Sulfur-Turf Microbial Mats in Japan

PubMed Central

Yamamoto, Hiroyuki; Hiraishi, Akira; Kato, Kenji; Chiura, Hiroshi X.; Maki, Yonosuke; Shimizu, Akira

1998-01-01

So-called sulfur-turf microbial mats, which are macroscopic white filaments or bundles consisting of large sausage-shaped bacteria and elemental sulfur particles, occur in sulfide-containing hot springs in Japan. However, no thermophiles from sulfur-turf mats have yet been isolated as cultivable strains. This study was undertaken to determine the phylogenetic positions of the sausage-shaped bacteria in sulfur-turf mats by direct cloning and sequencing of 16S rRNA genes amplified from the bulk DNAs of the mats. Common clones with 16S rDNA sequences with similarity levels of 94.8 to 99% were isolated from sulfur-turf mat samples from two geographically remote hot springs. Phylogenetic analysis showed that the phylotypes of the common clones formed a major cluster with members of the Aquifex-Hydrogenobacter complex, which represents the most deeply branching lineage of the domain bacteria. Furthermore, the bacteria of the sulfur-turf mat phylotypes formed a clade distinguishable from that of other members of the Aquifex-Hydrogenobacter complex at the order or subclass level. In situ hybridization with clone-specific probes for 16S rRNA revealed that the common phylotype of sulfur-turf mat bacteria is that of the predominant sausage-shaped bacteria. PMID:9572936

Cantera Integration with the Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS)

NASA Technical Reports Server (NTRS)

Lavelle, Thomas M.; Chapman, Jeffryes W.; May, Ryan D.; Litt, Jonathan S.; Guo, Ten-Huei

2014-01-01

NASA Glenn Research Center (GRC) has recently developed a software package for modeling generic thermodynamic systems called the Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS). T-MATS is a library of building blocks that can be assembled to represent any thermodynamic system in the Simulink(Registered TradeMark) (The MathWorks, Inc.) environment. These elements, along with a Newton Raphson solver (also provided as part of the T-MATS package), enable users to create models of a wide variety of systems. The current version of T-MATS (v1.0.1) uses tabular data for providing information about a specific mixture of air, water (humidity), and hydrocarbon fuel in calculations of thermodynamic properties. The capabilities of T-MATS can be expanded by integrating it with the Cantera thermodynamic package. Cantera is an object-oriented analysis package that calculates thermodynamic solutions for any mixture defined by the user. Integration of Cantera with T-MATS extends the range of systems that may be modeled using the toolbox. In addition, the library of elements released with Cantera were developed using MATLAB native M-files, allowing for quicker prototyping of elements. This paper discusses how the new Cantera-based elements are created and provides examples for using T-MATS integrated with Cantera.

Cantera Integration with the Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS)

NASA Technical Reports Server (NTRS)

Lavelle, Thomas M.; Chapman, Jeffryes W.; May, Ryan D.; Litt, Jonathan S.; Guo, Ten-Huei

2014-01-01

NASA Glenn Research Center (GRC) has recently developed a software package for modeling generic thermodynamic systems called the Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS). T-MATS is a library of building blocks that can be assembled to represent any thermodynamic system in the Simulink (The MathWorks, Inc.) environment. These elements, along with a Newton Raphson solver (also provided as part of the T-MATS package), enable users to create models of a wide variety of systems. The current version of T-MATS (v1.0.1) uses tabular data for providing information about a specific mixture of air, water (humidity), and hydrocarbon fuel in calculations of thermodynamic properties. The capabilities of T-MATS can be expanded by integrating it with the Cantera thermodynamic package. Cantera is an object-oriented analysis package that calculates thermodynamic solutions for any mixture defined by the user. Integration of Cantera with T-MATS extends the range of systems that may be modeled using the toolbox. In addition, the library of elements released with Cantera were developed using MATLAB native M-files, allowing for quicker prototyping of elements. This paper discusses how the new Cantera-based elements are created and provides examples for using T-MATS integrated with Cantera.

Morphological signatures of microbial activity across sediment and light microenvironments of Lake Vanda, Antarctica

NASA Astrophysics Data System (ADS)

Mackey, Tyler J.; Sumner, Dawn Y.; Hawes, Ian; Jungblut, Anne D.

2017-11-01

Cyanobacteria-dominated microbial mats in Lake Vanda grow with pinnacles and ridges separated by prostrate mat. Rocks protrude over microbial mats on the lake bottom to create localized, dm-scale gradients in sedimentation and irradiance. The effects of sedimentation on pinnacle and ridge growth were isolated from photosynthetic activity by contrasting growth across microenvironmental gradients. Sedimentation rate was measured as the mass of sand and mud sized sediment in mat that accumulated over 11 years, and the incident light was modeled near and under rocks by reconstructing topography using Structure from Motion techniques. Morphologically diverse pinnacles and ridges were documented in both exposed and sheltered mat microenvironments, in addition to growing downward from the underside of overhanging rocks. Mat that grew with > 40% irradiance under overhangs did not have consistent differences in pinnacle density or ridge abundance as a function of sedimentation rates or irradiance when compared to exposed mat. However, their morphology did change significantly with changes in the direction of incident irradiance. Where irradiance was < 40% ambient or light intersected the mat at very low angles, few pinnacles were present and ridges were preferentially aligned parallel to incident light direction. These observations indicate that pinnacle nucleation and spacing were not strongly influenced by sedimentation but pinnacle and ridge morphology varied in response to directional irradiance.

A study on tinea gladiatorum in young wrestlers and dermatophyte contamination of wrestling mats from Sari, Iran

PubMed Central

Hedayati, Mohammad T; Afshar, Parvaneh; Shokohi, Tahereh; Aghili, Reza

2007-01-01

Objective To study the prevalence of tinea gladiatorum among young wrestlers and dermatophyte contamination of wrestling mats from Sari city, the capital of Mazandaran, a northern province of Iran. Design 324 wrestlers (aged 9–20 years) from 7 active clubs in Sari city were examined, and skin scrapings were obtained from 135 wrestlers suspected of having tinea gladiatorum. The scraped skin samples were evaluated with potassium hydroxide. Pleated carpet sterile fragments (5×5 cm) were used for to survey of wrestling mat contamination. Sabouraud's dextrose agar with and without chloramphenicole and cyclohexamide was used to culture scrapings and wrestling mat samples. The dermatophytes were identified by routine laboratory techniques. Results Our study showed that of the 324 wrestlers, 65 (20.1%) had tinea gladiatorum. Most lesions were on the trunk and head. All the wrestling mat samples were positive for dermatophytes. Trichophyton tonsurans was isolated from all the scrapings and wrestling mat samples. Conclusion Considering that several colonies of T tonsurans were isolated from all the wrestling mats and from wrestlers with tinea gladiatorum (as the only dermatophyte species) we think that the contamination of wrestling mats with T tonsurans has a crucial role in the injection of wrestlers. PMID:17138633

Antimicrobial Activity of Silver Ions Released from Zeolites Immobilized on Cellulose Nanofiber Mats.

PubMed

Rieger, Katrina A; Cho, Hong Je; Yeung, Hiu Fai; Fan, Wei; Schiffman, Jessica D

2016-02-10

In this study, we exploit the high silver ion exchange capability of Linde Type A (LTA) zeolites and present, for the first time, electrospun nanofiber mats decorated with in-house synthesized silver (Ag(+)) ion exchanged zeolites that function as molecular delivery vehicles. LTA-Large zeolites with a particle size of 6.0 μm were grown on the surface of the cellulose nanofiber mats, whereas LTA-Small zeolites (0.2 μm) and three-dimensionally ordered mesoporous-imprinted (LTA-Meso) zeolites (0.5 μm) were attached to the surface of the cellulose nanofiber mats postsynthesis. After the three zeolite/nanofiber mat assemblies were ion-exchanged with Ag(+) ions, their ion release profiles and ability to inactivate Escherichia coli (E. coli) K12 were evaluated as a function of time. LTA-Large zeolites immobilized on the nanofiber mats displayed more than an 11 times greater E. coli K12 inactivation than the Ag-LTA-Large zeolites that were not immobilized on the nanofiber mats. This study demonstrates that by decorating nanometer to micrometer scale Ag(+) ion-exchanged zeolites on the surface of high porosity, hydrophilic cellulose nanofiber mats, we can achieve a tunable release of Ag(+) ions that inactivate bacteria faster and are more practical to use in applications over powder zeolites.

Geosynthetic Reinforcement of Sand-Mat Layer above Soft Ground

PubMed Central

Park, Jong-Beom; Park, Hyun-Soo; Kim, Daehyeon

2013-01-01

In order to improve the bearing capacity of soft ground for the purpose of getting trafficability of construction vehicles, the reinforcement of geosynthetics for sand-mat layers on soft ground has often been used. As the strength of the geosynthetics increases, and the sand-mat system becomes stronger, the bearing capacity of sand-mat systems will be increased. The depths of geosynthetics, reinforced in sand-mat layers, were varied with respect to the width of footing. The tensile strengths of geosynthetics were also varied to evaluate the effect of reinforcement on the bearing capacity of soft ground. The dispersion angles, with varying sand-mat thicknesses, were also determined in consideration of the tensile strength of geosynthetics and the depths of reinforcement installations. The bearing capacity ratios, with the variation of footing width and reinforced embedment depth, were determined for the geosynthetics-only, reinforced soft ground, 1-layer sand-mat system and 2-layer sand-mat system against the non-reinforced soft ground. From the test results of various models, a principle that better explains the concept of geosynthetic reinforcement has been found. On the basis of this principle, a new bearing capacity equation for practical use in the design of geosynthetically reinforced soft ground has been proposed by modifying Yamanouchi’s equation. PMID:28788392

Organismal and spatial partitioning of energy and macronutrient transformations within a hypersaline mat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mobberley, Jennifer M.; Lindemann, Stephen R.; Bernstein, Hans C.

2017-03-21

Phototrophic mat communities are model ecosystems for studying energy cycling and elemental transformations because complete biogeochemical cycles occur over millimeter-to-centimeter scales. Characterization of energy and nutrient capture within hypersaline phototrophic mats has focused on specific processes and organisms, however little is known about community-wide distribution of and linkages between these processes. To investigate energy and macronutrient capture and flow through a structured community, the spatial and organismal distribution of metabolic functions within a compact hypersaline mat community from Hot Lake have been broadly elucidated through species-resolved metagenomics and geochemical, microbial diversity, and metabolic gradient measurements. Draft reconstructed genomes of abundantmore » organisms revealed three dominant cyanobacterial populations differentially distributed across the top layers of the mat suggesting niche separation along light and oxygen gradients. Many organisms contained diverse functional profiles, allowing for metabolic response to changing conditions within the mat. Organisms with partial nitrogen and sulfur metabolisms were widespread indicating dependence upon metabolite exchange. In addition, changes in community spatial structure were observed over the diel. These results indicate that organisms within the mat community have adapted to the temporally dynamic environmental gradients in this hypersaline mat through metabolic flexibility and fluid syntrophic interactions, including shifts in spatial arrangements.« less

Modifying landing mat material properties may decrease peak contact forces but increase forefoot forces in gymnastics landings.

PubMed

Mills, Chris; Yeadon, Maurice R; Pain, Matthew T G

2010-09-01

This study investigated how changes in the material properties of a landing mat could minimise ground reaction forces (GRF) and internal loading on a gymnast during landing. A multi-layer model of a gymnastics competition landing mat and a subject-specific seven-link wobbling mass model of a gymnast were developed to address this aim. Landing mat properties (stiffness and damping) were optimised using a Simplex algorithm to minimise GRF and internal loading. The optimisation of the landing mat parameters was characterised by minimal changes to the mat's stiffness (<0.5%) but increased damping (272%) compared to the competition landing mat. Changes to the landing mat resulted in reduced peak vertical and horizontal GRF and reduced bone bending moments in the shank and thigh compared to a matching simulation. Peak bone bending moments within the thigh and shank were reduced by 6% from 321.5 Nm to 302.5Nm and GRF by 12% from 8626 N to 7552 N when compared to a matching simulation. The reduction in these forces may help to reduce the risk of bone fracture injury associated with a single landing and reduce the risk of a chronic injury such as a stress fracture.

Enhancement of immune response induced by DNA vaccine cocktail expressing complete LACK and TSA genes against Leishmania major.

PubMed

Ghaffarifar, Fatemeh; Jorjani, Ogholniaz; Sharifi, Zohreh; Dalimi, Abdolhossein; Hassan, Zuhair M; Tabatabaie, Fatemeh; Khoshzaban, Fariba; Hezarjaribi, Hajar Ziaei

2013-04-01

Leishmaniasis is an important disease in humans. Leishmania homologue of receptor for Activated C Kinase (LACK) and thiol specific antioxidant (TSA) as immuno-dominant antigens of Leishmania major are considered the most promising molecules for a DNA vaccine. We constructed a DNA cocktail, containing plasmids encoding LACK and TSA genes of Leishmania major and evaluated the immune response and survival rate in BALB/c mice. IgG and Interferon gamma values were noticeably increased in the immunized group with DNA cocktail vaccine, which were significantly higher than those in the single-gene vaccinated and control groups (p < 0.05) following the immunization and after challenging with Leishmania major. Interleukin 4 values were decreased in all immunized groups, but only in DNA vaccine cocktail and single-gene vaccination with pc-LACK there were statistical differences with control groups (p > 0.05). The immunized mice with the cocktail DNA vaccine presented a considerable reduction in diameter of lesion compared to other groups and a significant difference was observed (p < 0.05) in this regard. The survival time of the immunized mice with the cocktail DNA vaccine was significantly higher than that in the other groups (p < 0.05) after their being challenged with Leishmania major. The findings of this study indicated that the cocktail DNA vaccine increased the cellular response and survival rate and induced protection against infection with Leishmania in the mice. © 2012 The Authors © 2012 APMIS.

Deficiency of PTP1B in leptin receptor-expressing neurons leads to decreased body weight and adiposity in mice.

PubMed

Tsou, Ryan C; Zimmer, Derek J; De Jonghe, Bart C; Bence, Kendra K

2012-09-01

Protein tyrosine phosphatase 1B (PTP1B) is a ubiquitously expressed tyrosine phosphatase implicated in the negative regulation of leptin and insulin receptor signaling. PTP1B(-/-) mice possess a lean metabolic phenotype attributed at least partially to improved hypothalamic leptin sensitivity. Interestingly, mice lacking both leptin and PTP1B (ob/ob:PTP1B(-/-)) have reduced body weight compared with mice lacking leptin only, suggesting that PTP1B may have important leptin-independent metabolic effects. We generated mice with PTP1B deficiency specifically in leptin receptor (LepRb)-expressing neurons (LepRb-PTP1B(-/-)) and compared them with LepRb-Cre-only wild-type (WT) controls and global PTP1B(-/-) mice. Consistent with PTP1B's role as a negative regulator of leptin signaling, our results show that LepRb-PTP1B(-/-) mice are leptin hypersensitive and have significantly reduced body weight when maintained on chow or high-fat diet (HFD) compared with WT controls. LepRb-PTP1B(-/-) mice have a significant decrease in adiposity on HFD compared with controls. Notably, the extent of attenuated body weight gain on HFD, as well as the extent of leptin hypersensitivity, is similar between LepRb-PTP1B(-/-) mice and global PTP1B(-/-) mice. Overall, these results demonstrate that PTP1B deficiency in LepRb-expressing neurons results in reduced body weight and adiposity compared with WT controls and likely underlies the improved metabolic phenotype of global and brain-specific PTP1B-deficient models. Subtle phenotypic differences between LepRb-PTP1B(-/-) and global PTP1B(-/-) mice, however, suggest that PTP1B independent of leptin signaling may also contribute to energy balance in mice.

Iron misregulation and neurodegenerative disease in mouse models that lack iron regulatory proteins

PubMed Central

Ghosh, Manik C.; Zhang, De-Liang; Rouault, Tracey A.

2015-01-01

Iron regulatory proteins 1 and 2 (IRP1 and IRP2) are two cytosolic proteins that maintain cellular iron homeostasis by binding to RNA stem loops known as iron responsive elements (IREs) that are found in the untranslated regions of target mRNAs that encode proteins involved in iron metabolism. IRPs modify expression of iron metabolism genes, and global and tissue-specific knockout mice have been made to evaluate the physiological significance of these iron regulatory proteins (Irps). Here, we will discuss the results of the studies that have been performed with mice engineered to lack expression of one or both Irps, and made in different strains using different methodologies. Both Irp1 and Irp2 knockout mice are viable, but the double knockout (Irp1−/−Irp2−/−) mice die before birth, indicating that these Irps play a crucial role in maintaining iron homeostasis. Irp1−/− mice develop polycythemia and pulmonary hypertension, and when these mice are challenged with a low iron diet, they die early of abdominal hemorrhages, suggesting that Irp1 plays an essential role in erythropoiesis and in the pulmonary and cardiovascular systems. Irp2−/− mice develop microcytic anemia, erythropoietic protoporphyria and a progressive neurological disorder, indicating that Irp2 has important functions in the nervous system and erythropoietic homeostasis. Several excellent review articles have recently been published on Irp knockout mice that mainly focus on Irp1−/− mice (referenced in the introduction). In this review, we will briefly describe the phenotypes and physiological implications of Irp1−/− mice, and will discuss the phenotypes observed for Irp2−/− mice in detail with a particular emphasis on the neurological problems of these mice. PMID:25771171

Reduced Gas Cycling in Microbial Mats: Implications for Early Earth

NASA Technical Reports Server (NTRS)

Hoehler, Tori M.; Bebout, Brad M.; DesMarais, David J.; DeVincenzi, Donald L. (Technical Monitor)

2000-01-01

For more than half the history of life on Earth, biological productivity was dominated by photosynthetic microbial mats. During this time, mats served as the preeminent biological influence on earth's surface and atmospheric chemistry and also as the primary crucible for microbial evolution. We find that modern analogs of these ancient mat communities generate substantial quantities of hydrogen, carbon monoxide, and methane. Escape of these gases from the biosphere would contribute strongly to atmospheric evolution and potentially to the net oxidation of earth's surface; sequestration within the biosphere carries equally important implications for the structure, function, and evolution of anaerobic microbial communities within the context of mat biology.

Testlet-Based Multidimensional Adaptive Testing.

PubMed

Frey, Andreas; Seitz, Nicki-Nils; Brandt, Steffen

2016-01-01

Multidimensional adaptive testing (MAT) is a highly efficient method for the simultaneous measurement of several latent traits. Currently, no psychometrically sound approach is available for the use of MAT in testlet-based tests. Testlets are sets of items sharing a common stimulus such as a graph or a text. They are frequently used in large operational testing programs like TOEFL, PISA, PIRLS, or NAEP. To make MAT accessible for such testing programs, we present a novel combination of MAT with a multidimensional generalization of the random effects testlet model (MAT-MTIRT). MAT-MTIRT compared to non-adaptive testing is examined for several combinations of testlet effect variances (0.0, 0.5, 1.0, and 1.5) and testlet sizes (3, 6, and 9 items) with a simulation study considering three ability dimensions with simple loading structure. MAT-MTIRT outperformed non-adaptive testing regarding the measurement precision of the ability estimates. Further, the measurement precision decreased when testlet effect variances and testlet sizes increased. The suggested combination of the MTIRT model therefore provides a solution to the substantial problems of testlet-based tests while keeping the length of the test within an acceptable range.

Microbial mat of the thermal springs Kuchiger Republic of Buryatia: species composition, biochemical properties and electrogenic activity in biofuel cell

NASA Astrophysics Data System (ADS)

Aleksandrovich Yuriev, Denis; Viktorovna Zaitseva, Svetlana; Olegovna Zhdanova, Galina; Yurievich Tolstoy, Mikhail; Dondokovna Barkhutova, Darima; Feodorovna Vyatchina, Olga; Yuryevna Konovalova, Elena; Iosifovich Stom, Devard

2018-02-01

Electrogenic, molecular and some other properties of a microbial mat isolated from the Kuchiger hot spring (Kurumkansky District, Republic of Buryatia) were studied. Molecular analysis showed that representatives of Proteobacteria (85.5 % of the number of classified bacterial sequences) prevailed in the microbial mat of the Kuchiger springs, among which sulfur bacteria of the genus Thiothrix were the most numerous. In the microbial mat there were bacteria from the families Rhodocyclaceae, Comamonadaceae and Flavobacteriaceae. Phylum Bacteroidetes, Cyanobacteria/Chloroplast, Fusobacteria, Fibrobacteres, Acidobacteria, Chlorobi, Spirochaetes, Verrucomicrobia, Firmicutes, Deinococcus-Thermus, Chloroflexi and Actinobacteria are also noted in the composition of the microbial mat. Under the experimental conditions using Kuchiger-mat 16 as bioagents, glucose and peptone as substrates, the power of BFC was 240 and 221 mW / m2, respectively. When replacing the substrate with sodium acetate, the efficiency of the BFC was reduced by a factor of 10 (20 mW / m2). The prospects of using a microbial mat “Kuchiger-16” as an electrogen in BFC when utilizing alkaline waste water components to generate electricity are discussed.

Toxic cyanobacteria and cyanotoxins in public hot springs in Saudi Arabia.

PubMed

Mohamed, Zakaria A

2008-01-01

Toxic cyanobacteria are well reported in rivers, lakes and even marine environments, but the toxin production of cyanobacteria in hot springs is largely unexplored. Therefore, the present study investigated the presence of toxic cyanobacteria and cyanotoxins in public hot springs in Saudi Arabia. The results of an enzyme-linked immunosorbent assay (ELISA) revealed that Saudi spring cyanobacterial mats contained microcystins (MCYSTs) at concentrations ranging from 468 to 512.5 microg g(-1). The Limulus amebocyte lystae (LAL) assay detected lipopolysaccharide (LPS) endotoxins in these mats at concentrations ranging from 433.3 to 506.8 EU g(-1). MCYSTs and endotoxins were also detected in spring waters at levels of 5.7 microg l(-1) and 640 EU ml(-1), respectively, exceeding WHO's provisional guideline value for MCYST-LR in drinking-water. High-performance liquid chromatography (HPLC) analysis revealed that only Oscillatoria limosa and Synechococcus lividus can produce MCYSTs with a profile consisting of MCYST-RR and -LR. Based on the LAL assay, 12 out of 17 cyanobacterial species contained LPS at concentrations ranging from 0.93 to 21.06 EU g(-1). However, not all LPS of these species were toxic to mice. This study suggests that the hot springs in the world including Saudi Arabia should be screened for toxic cyanobacteria to avoid the exposure of people recreating and bathing in spring waters to cyanobacterial toxins.

Biogeochemistry of Stinking Springs, Utah. Part II: Microbial Diversity and Photo- and Chemo-Autotrophic Growth Rates in a Layered Microbial Mat

NASA Astrophysics Data System (ADS)

Monteverde, D.; Metzger, J. G.; Bournod, C.; Kelly, H.; Johnson, H.; Sessions, A. L.; Osburn, M.; Shapiro, R. S.; Rideout, J.; Johnston, D. T.; Stevenson, B.; Stamps, B. W.; Vuono, D.; Hanselmann, K.; Spear, J. R.

2013-12-01

Layered microbial mats have garnered attention for their high phylogenetic diversity and exploitation of geochemical gradients often on the mm scale. However, despite their novelty and implications for early life diversification, little is known about layered microbial mat growth rates or the interdependence of the microbial communities within the system. Stinking Springs, a warm, sulfidic, saline spring northeast of the Great Salt Lake, serves as our test-site to investigate some of these questions. Stinking Springs undergoes downstream changes in pH (6.59-8.14), sulfide (527μM - below detection), sulfate (13-600μM), TCO2 (7.77-3.71mM), and temperature (40-21°C) along its ~150m flow path. The first 10m of discharge is channelized, beyond that, the spring supports a 10 to 40mm-thick layered microbial mat covering ~40% of the total spring runoff area. The mat was divided into four texturally-distinct layers which were each analyzed for 16S rRNA, lipid abundance, and bicarbonate and acetate uptake rates in addition to standard microscopy analyses. 16S rRNA analyses confirmed high taxa diversity within each layer, which varied significantly in taxa makeup such that no single phylum dominated the abundance (>33%) in more than one mat layer. The taxonomic diversity tended to increase with mat depth, a similar finding to other studies on layered microbial mats. A mat sampling transect across 16 meters showed that layer taxonomic diversity was conserved horizontally for all four mat layers, which implies mat depth has a larger control on diversity than physical or chemical parameters. Microscopy indicated the presence of diatoms in all layers which was confirmed by lipid abundance of sterols and long-branch fatty acid methyl esters. Incubation experiments were conducted in light and dark conditions over 24 hours with separate 13C-tagged bicarbonate and acetate additions. Heterotrophic growth rates (acetate uptake; 0.03-0.65%/day) were higher than autotrophic growth rates (bicarbonate uptake; 0-0.16%/day) under both dark and light conditions. Light conditions yielded higher growth rates for both heterotrophs and autotrophs and the highest rates were consistently found in the top mat layer and decreased with depth. The addition of 13C-acetate and concomitant high uptake is a measure of potential heterotrophy since in situ acetate concentrations are unlikely to be as high. 13C-bicarbonate uptake, on the other hand, should quantitatively represent the autotrophic growth rate. The Stinking Spring layered microbial mats display high taxonomic diversity, which is conserved horizontally across distances of meters and varies significantly with depth. Mats experience highest growth in the surface layer likely driven by phototrophs; high rates of bicarbonate uptake in the dark indicate considerable chemoautotrophy. Covariation in the heterotroph growth rates and 16S rRNA heterotroph abundance with mat depth indicates that heterotrophy may play an important role in the growth of these layered mats.

Phenotype analysis of male transgenic mice overexpressing mutant IGFBP-2 lacking the Cardin-Weintraub sequence motif: Reduced expression of synaptic markers and myelin basic protein in the brain and a lower degree of anxiety-like behaviour.

PubMed

Schindler, N; Mayer, J; Saenger, S; Gimsa, U; Walz, C; Brenmoehl, J; Ohde, D; Wirthgen, E; Tuchscherer, A; Russo, V C; Frank, M; Kirschstein, T; Metzger, F; Hoeflich, A

2017-04-01

Brain growth and function are regulated by insulin-like growth factors I and II (IGF-I and IGF-II) but also by IGF-binding proteins (IGFBPs), including IGFBP-2. In addition to modulating IGF activities, IGFBP-2 interacts with a number of components of the extracellular matrix and cell membrane via a Cardin-Weintraub sequence or heparin binding domain (HBD1). The nature and the signalling elicited by these interactions are not fully understood. Here, we examined transgenic mice (H1d-hBP2) overexpressing a mutant human IGFBP-2 that lacks a specific heparin binding domain (HBD1) known as the Cardin-Weintraub sequence. H1d-hBP2 transgenic mice have the genetic background of FVB mice and are characterized by severe deficits in brain growth throughout their lifetime (p<0.05). In tissue lysates from brain hemispheres of 12-21day old male mice, protein levels of the GTPase dynamin-I were significantly reduced (p<0.01). Weight reductions were also found in distinct brain regions in two different age groups (12 and 80weeks). In the younger group, impaired weights were observed in the hippocampus (-34%; p<0.001), cerebellum (-25%; p<0.0001), olfactory bulb (-31%; p<0.05) and prefrontal cortex (-29%; p<0.05). At an age of 12weeks expression of myelin basic protein was reduced (p<0.01) in H1d-BP-2 mice in the cerebellum but not in the hippocampus. At 80weeks of age, weight reductions were similarly present in the cerebellum (-28%; p<0.001) and hippocampus (-31; p<0.05). When mice were challenged in the elevated plus maze, aged but not younger H1d-hBP2 mice displayed significantly less anxiety-like behaviour, which was also observed in a second transgenic mouse model overexpressing mouse IGFBP-2 lacking HBD1 (H1d-mBP2). These in vivo studies provide, for the first time, evidence for a specific role of IGFBP-2 in brain functions associated with anxiety and risk behaviour. These activities of IGFBP-2 could be mediated by the Cardin-Weintraub/HBD1 sequence and are altered in mice expressing IGFBP-2 lacking the HBD1. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Attenuated and Replication-Competent Vaccinia Virus Strains M65 and M101 with Distinct Biology and Immunogenicity as Potential Vaccine Candidates against Pathogens

PubMed Central

Sánchez-Sampedro, Lucas; Gómez, Carmen Elena; Mejías-Pérez, Ernesto; Pérez-Jiménez, Eva; Oliveros, Juan Carlos

2013-01-01

Replication-competent poxvirus vectors with an attenuation phenotype and with a high immunogenic capacity of the foreign expressed antigen are being pursued as novel vaccine vectors against different pathogens. In this investigation, we have examined the replication and immunogenic characteristics of two vaccinia virus (VACV) mutants, M65 and M101. These mutants were generated after 65 and 101 serial passages of persistently infected Friend erythroleukemia (FEL) cells. In cultured cells of different origins, the mutants are replication competent and have growth kinetics similar to or slightly reduced in comparison with those of the parental Western Reserve (WR) virus strain. In normal and immune-suppressed infected mice, the mutants showed different levels of attenuation and pathogenicity in comparison with WR and modified vaccinia Ankara (MVA) strains. Wide genome analysis after deep sequencing revealed selected genomic deletions and mutations in a number of viral open reading frames (ORFs). Mice immunized in a DNA prime/mutant boost regimen with viral vectors expressing the LACK (Leishmania homologue for receptors of activated C kinase) antigen of Leishmania infantum showed protection or a delay in the onset of cutaneous leishmaniasis. Protection was similar to that triggered by MVA-LACK. In immunized mice, both polyfunctional CD4+ and CD8+ T cells with an effector memory phenotype were activated by the two mutants, but the DNA-LACK/M65-LACK protocol preferentially induced CD4+ whereas DNA-LACK/M101-LACK preferentially induced CD8+ T cell responses. Altogether, our findings showed the adaptive changes of the WR genome during long-term virus-host cell interaction and how the replication competency of M65 and M101 mutants confers distinct biological properties and immunogenicity in mice compared to those of the MVA strain. These mutants could have applicability for understanding VACV biology and as potential vaccine vectors against pathogens and tumors. PMID:23596295

Impaired humoral immunity and tolerance in K14-VEGFR-3-Ig mice that lack dermal lymphatic drainage

PubMed Central

Thomas, Susan N.; Rutkowski, Joseph M.; Pasquier, Miriella; Kuan, Emma L.; Alitalo, Kari; Randolph, Gwendalyn J.; Swartz, Melody A.

2012-01-01

Lymphatic vessels transport interstitial fluid, soluble antigen, and immune cells from peripheral tissues to lymph nodes (LNs), yet the contribution of peripheral lymphatic drainage to adaptive immunity remains poorly understood. We examined immune responses to dermal vaccination and contact hypersensitivity (CHS) challenge in K14-VEGFR-3-Ig mice, which lack dermal lymphatic capillaries and experience markedly depressed transport of solutes and dendritic cells from the skin to draining LNs. In response to dermal immunization, K14-VEGFR-3-Ig mice produced lower antibody titers. In contrast, although delayed, T cell responses were robust after 21 days, including high levels of antigen-specific CD8+ T cells and production of IFN-γ, IL-4 and IL-10 upon restimulation. T cell-mediated CHS responses were strong in K14-VEGFR-3-Ig mice, but importantly, their ability to induce CHS tolerance in the skin was impaired. Additionally, one-year-old mice displayed multiple signs of autoimmunity. These data suggest that lymphatic drainage plays more important roles in regulating humoral immunity and peripheral tolerance than in effector T cell immunity. PMID:22844119

Mild deficits in mice lacking pituitary adenylate cyclase-activating polypeptide receptor type 1 (PAC1) performing on memory tasks.

PubMed

Sauvage, M; Brabet, P; Holsboer, F; Bockaert, J; Steckler, T

2000-12-08

Pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptor subtype 1 (PAC1) have been suggested to play a role in the modulation of learning and memory. However, behavioral evidence for altered mnemonic function due to altered PAC1 activity is missing. Therefore, the role of PAC1 in learning and memory was studied in mouse mutants lacking this receptor (PAC1 knock-out mice), tested in water maze two-choice spatial discrimination, one-trial contextual and cued fear conditioning, and multiple-session contextual discrimination. Water maze spatial discrimination was unaffected in PAC1 mutants, while a mild deficit was observed in multiple session contextual discrimination in PAC1 knock-out mice. Furthermore, PAC1 knock-out mice were able to learn the association between context and shock in one-trial contextual conditioning, but showed faster return to baseline than wild-type mice. Thus, the effects of PAC1 knock-out on modulating performance in these tasks were subtle and suggest that PAC1 only plays a limited role in learning and memory.

Biogeochemistry of hypersaline microbial mats illustrates the dynamics of modern microbial ecosystems and the early evolution of the biosphere

NASA Technical Reports Server (NTRS)

Des Marais, David J.

2003-01-01

Photosynthetic microbial mats are remarkably complete self-sustaining ecosystems at the millimeter scale, yet they have substantially affected environmental processes on a planetary scale. These mats may be direct descendents of the most ancient biological communities in which even oxygenic photosynthesis might have developed. Photosynthetic mats are excellent natural laboratories to help us to learn how microbial populations associate to control dynamic biogeochemical gradients.

Study on the Strength of GFRP/Stainless Steel Adhesive Joints Reinforced with Glass Mat

NASA Astrophysics Data System (ADS)

Iwasa, Masaaki

The adhesive strengths of glass fiber reinforced plastics/metal adhesive joints reinforced with glass mat under tensile shear loads and tensile loads were investigated analytically and experimentally. First, the stress singularity parameters of the bonding edges were analyzed by FEM for various types of adhesive joints reinforced with glass mat. The shear stress and normal stress distributions near the bonding edge can be expressed by two stress singularity parameters. Second, tensile shear tests were performed on taper lap joint and taper lap joint reinforced with glass mat and tensile tests were performed on T-type adhesive joint and T-type adhesive joint reinforced with glass mat. The relationships between the loads and the crosshead displacements were measured. We concluded that reinforcing adhesive joints has a greater effect on strength under tensile load than under tensile shear load. The adhesive joints strength reinforced with glass mat can be evaluated by using stress singularity parameters.

Community living long before man: fossil and living microbial mats and early life

NASA Technical Reports Server (NTRS)

Margulis, L.; Lopez Baluja, L.; Awramik, S. M.; Sagan, D.

1986-01-01

Microbial mats are layered communities of bacteria that form cohesive structures, some of which are preserved in sedimentary rocks as stromatolites. Certain rocks, approximately three and a half thousand million years old and representing the oldest known fossils, are interpreted to derive from microbial mats and to contain fossils of microorganisms. Modern microbial mats (such as the one described here from Matanzas, Cuba) and their fossil counterparts are of great interest in the interpretation of early life on Earth. Since examination of microbial mats and stromatolites increases our understanding of long-term stability and change, within the global environment, such structures should be protected wherever possible as natural science preserves. Furthermore, since they have existed virtually from the time of life's origin, microbial mats have developed exemplary mechanisms of local community persistence and may even play roles in the larger global environment that we do not understand.

Enhancing the Mechanical Properties of Electrospun Nanofiber Mats through Controllable Welding at the Cross Points.

PubMed

Li, Haoxuan; Zhu, Chunlei; Xue, Jiajia; Ke, Qinfei; Xia, Younan

2017-05-01

This communication describes a simple and effective method for welding electrospun nanofibers at the cross points to enhance the mechanical properties of their nonwoven mats. The welding is achieved by placing a nonwoven mat of the nanofibers in a capped vial with the vapor of a proper solvent. For polycaprolactone (PCL) nanofibers, the solvent is dichloromethane (DCM). The welding can be managed in a controllable fashion by simply varying the partial pressure of DCM and/or the exposure time. Relative to the pristine nanofiber mat, the mechanical strength of the welded PCL nanofiber mat can be increased by as much as 200%. Meanwhile, such a treatment does not cause any major structural changes, including morphology, fiber diameter, and pore size. This study provides a generic method for improving the mechanical properties of nonwoven nanofiber mats, holding great potential in various applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Research on Bayes matting algorithm based on Gaussian mixture model

NASA Astrophysics Data System (ADS)

Quan, Wei; Jiang, Shan; Han, Cheng; Zhang, Chao; Jiang, Zhengang

2015-12-01

The digital matting problem is a classical problem of imaging. It aims at separating non-rectangular foreground objects from a background image, and compositing with a new background image. Accurate matting determines the quality of the compositing image. A Bayesian matting Algorithm Based on Gaussian Mixture Model is proposed to solve this matting problem. Firstly, the traditional Bayesian framework is improved by introducing Gaussian mixture model. Then, a weighting factor is added in order to suppress the noises of the compositing images. Finally, the effect is further improved by regulating the user's input. This algorithm is applied to matting jobs of classical images. The results are compared to the traditional Bayesian method. It is shown that our algorithm has better performance in detail such as hair. Our algorithm eliminates the noise well. And it is very effectively in dealing with the kind of work, such as interested objects with intricate boundaries.

Epac Signaling Is Required for Cocaine-Induced Change in AMPA Receptor Subunit Composition in the Ventral Tegmental Area.

PubMed

Liu, Xiaojie; Chen, Yao; Tong, Jiaqing; Reynolds, Ashley M; Proudfoot, Sarah C; Qi, Jinshun; Penzes, Peter; Lu, Youming; Liu, Qing-Song

2016-04-27

Exchange protein directly activated by cAMP (Epac) and protein kinase A (PKA) are intracellular receptors for cAMP. Although PKA and its downstream effectors have been studied extensively in the context of drug addiction, whether and how Epac regulates cellular and behavioral effects of drugs of abuse remain essentially unknown. Epac is known to regulate AMPA receptor (AMPAR) trafficking. Previous studies have shown that a single cocaine exposure in vivo leads to an increase in GluA2-lacking AMPARs in dopamine neurons of the ventral tegmental area (VTA). We tested the hypothesis that Epac mediates cocaine-induced changes in AMPAR subunit composition in the VTA. We report that a single cocaine injection in vivo in wild-type mice leads to inward rectification of EPSCs and renders EPSCs sensitive to a GluA2-lacking AMPAR blocker in VTA dopamine neurons. The cocaine-induced increase in GluA2-lacking AMPARs was absent in Epac2-deficient mice but not in Epac1-deficient mice. In addition, activation of Epac with the selective Epac agonist 8-CPT-2Me-cAMP (8-CPT) recapitulated the cocaine-induced increase in GluA2-lacking AMPARs, and the effects of 8-CPT were mediated by Epac2. We also show that conditioned place preference to cocaine was impaired in Epac2-deficient mice and in mice in which Epac2 was knocked down in the VTA but was not significantly altered in Epac1-deficient mice. Together, these results suggest that Epac2 is critically involved in the cocaine-induced change in AMPAR subunit composition and drug-cue associative learning. Addictive drugs, such as cocaine, induce long-lasting adaptions in the reward circuits of the brain. A single intraperitoneal injection of cocaine leads to changes in the composition and property of the AMPAR that carries excitatory inputs to dopamine neurons. Here, we provide evidence that exchange protein directly activated by cAMP (Epac), a cAMP sensor protein, is required for the cocaine-induced changes of the AMPAR. We found that the effects of cocaine were mimicked by activation of Epac but were blocked by genetic deletion of Epac. Furthermore, cocaine-cue associative learning was impaired in mice lacking Epac. These findings uncovered a critical role of Epac in regulating the cellular and behavioral actions of cocaine. Copyright © 2016 the authors 0270-6474/16/364802-14$15.00/0.

Reconstructing Century-Scale Changes in Nitrogen Cycling in Forests Throughout the United States using Tree-Ring δ15N Chronologies

NASA Astrophysics Data System (ADS)

Gerhart-Barley, L.; McLauchlan, K. K.; Battles, J. J.; Craine, J. M.; Higuera, P. E.; Mack, M. C.; McNeil, B. E.; Nelson, D. M.; Pederson, N.; Perakis, S. S.

2016-12-01

In recent decades, human perturbation of the global nitrogen (N) cycle has been immense with reactive nitrogen supply to ecosystems from anthropogenic sources now exceeding that of natural fixation. The impact of these perturbations on ecosystem nutrient cycling and plant communities is limited by the lack of long-term `baseline' assessments of N cycling prior to anthropogenic influences. Stable N isotope analysis (δ15N) of dendrochronological records have the potential to provide this baseline data, but to date have focused on short term, regional assessments. Here, we address this question with a data set incorporating 311 individual trees and 7,661 δ15N measurements from 50 sites throughout the contiguous United States. These sites represent the diversity of US forest types, climate conditions, N deposition, soil types, and disturbance histories. The chronologies span, on average, the last 162 calendar years, with the oldest chronology dating back to 1572 C.E. Consequently, this study is the first century- and continental-scale assessment of ecosystem N cycling using tree-ring chronologies. When aggregated, the chronologies show a consistent decline from 1825 C.E. to present, indicating declining N availability in US forests, despite global increases in N supply. Environmental factors such as mean annual precipitation (MAP), mean annual temperature (MAT), and mean annual nitrogen deposition (Ndep) did not contribute to average site δ15N values; however, MAP and MAT significantly affected temporal trajectories in tree-ring δ15N, with more negative slopes toward present occurring in regions with low MAT and high MAP. Quantity of atmospheric N deposition had no discernible impact on mean δ15N values or on the temporal slope. This lack of response is either because levels of N deposition are too low to produce a discernible response in any meaningful aspects of the N cycle, and/or the δ15N signature of depositional N is similar enough to ecosystem N pools that atmospheric N inputs do not produce a significant effect. The declines in N availability indicated by these data may be exacerbated by projected climate trends, which predict increasing temperatures and drier conditions, potentially reducing overall carbon uptake in US forests.

Forensic botany II, DNA barcode for land plants: Which markers after the international agreement?

PubMed

Ferri, G; Corradini, B; Ferrari, F; Santunione, A L; Palazzoli, F; Alu', M

2015-03-01

The ambitious idea of using a short piece of DNA for large-scale species identification (DNA barcoding) is already a powerful tool for scientists and the application of this standard technique seems promising in a range of fields including forensic genetics. While DNA barcoding enjoyed a remarkable success for animal identification through cytochrome c oxidase I (COI) analysis, the attempts to identify a single barcode for plants remained a vain hope for a longtime. From the beginning, the Consortium for the Barcode of Life (CBOL) showed a lack of agreement on a core plant barcode, reflecting the diversity of viewpoints. Different research groups advocated various markers with divergent set of criteria until the recent publication by the CBOL-Plant Working Group. After a four-year effort, in 2009 the International Team concluded to agree on standard markers promoting a multilocus solution (rbcL and matK), with 70-75% of discrimination to the species level. In 2009 our group firstly proposed the broad application of DNA barcoding principles as a tool for identification of trace botanical evidence through the analysis of two chloroplast loci (trnH-psbA and trnL-trnF) in plant species belonging to local flora. Difficulties and drawbacks that were encountered included a poor coverage of species in specific databases and the lack of authenticated reference sequences for the selected markers. Successful preliminary results were obtained providing an approach to progressively identify unknown plant specimens to a given taxonomic rank, usable by any non-specialist botanist or in case of a shortage of taxonomic expertise. Now we considered mandatory to update and to compare our previous findings with the new selected plastid markers (matK+rbcL), taking into account forensic requirements. Features of all the four loci (the two previously analyzed trnH-psbA+trnL-trnF and matK+rbcL) were compared singly and in multilocus solutions to assess the most suitable combination for forensic botany. Based on obtained results, we recommend the adoption of a two-locus combination with rbcL+trnH-psbA plastid markers, which currently best satisfies forensic needs for botanical species identification. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Activation of inflammatory signaling by lipopolysaccharide produces a prolonged increase of voluntary alcohol intake in mice

PubMed Central

Blednov, Y.A.; Benavidez, J.M.; Geil, C.; Perra, S.; Morikawa, H.; Harris, R.A.

2011-01-01

Previous studies showed that mice with genetic predisposition for high alcohol consumption as well as human alcoholics show changes in brain expression of genes related to immune signaling. In addition, mutant mice lacking genes related to immune function show decreased alcohol consumption (Blednov et al., in press), suggesting that immune signaling promotes alcohol consumption. To test the possibility that activation of immune signaling will increase alcohol consumption, we treated mice with lipopolysaccaride (LPS; 1 mg/kg, i.p.) and tested alcohol consumption in the continuous two-bottle choice test. To take advantage of the long-lasting activation of brain immune signaling by LPS, we measured drinking beginning one week or one month after LPS treatment and continued the studies for several months. LPS produced persistent increases in alcohol consumption in C57/Bl6 J (B6) inbred mice, FVBxB6F1 and B6xNZBF1 hybrid mice, but not in FVB inbred mice. To determine if this effect of LPS is mediated through binding to TLR4, we tested mice lacking CD14, a key component of TLR4 signaling. These null mutants showed no increase of alcohol intake after treatment with LPS. LPS treatment decreased ethanol-conditioned taste aversion but did not alter ethanol-conditioned place preference (B6xNZBF1 mice). Electro-physiological studies of dopamine neurons in the ventral tegmental area showed that pretreatment of mice with LPS decreased the neuronal firing rate. These results suggest that activation of immune signaling promotes alcohol consumption and alters certain aspects of alcohol reward/aversion. PMID:21266194

Detection of Toxoplasma gondii DNA in the milk of naturally infected ewes.

PubMed

Camossi, L G; Greca-Júnior, H; Corrêa, A P F L; Richini-Pereira, V B; Silva, R C; Da Silva, A V; Langoni, H

2011-05-11

Toxoplasmosis is the major parasitic disease affecting sheep. It is important for veterinary medicine, animal science and public health since it causes reproductive and economic losses in the herd, as well as damaging human health due to consumption of contaminated meat and milk, which can facilitate zoonotic transmission. Detection of Toxoplasma gondii in ovine milk and lack of data in the literature describing differentiation between acute and chronic disease for this species stimulated the elaboration of the present research project. To achieve the aim of this study, the animals were allocated to two groups of 20 ewes each, of which group 1 was composed of animals with positive serology and group 2 with negative serology. Acute and chronic stages of the disease were differentiated by modified direct agglutination test (MAT), in which antigens were fixed with formalin (MAT-AF) and methanol (MAT-AM). The parasite was detected in milk by polymerase chain reaction (PCR), and the molecular identity of the amplified products was confirmed by sequencing. The serological results indicated that sheep had a chronic infection profile. T. gondii DNA was detected in seven milk samples from five seropositive sheep, and twice in milk of two sheep. Sequences of species shared 97-100% identity with T. gondii. These findings allowed the hypothesis that the peripartum period may also lead to the resurgence of tissue T. gondii tachyzoites cysts which can circulate again and be excreted in the milk. This study used sheep naturally infected with T. gondii as a prerequisite for further investigations on the possible participation of this species in toxoplasmosis epidemiology and as a potential transmission route related to consumption of milk from infected sheep. Copyright © 2010 Elsevier B.V. All rights reserved.

Clinical features associated with copy number variations of the 14q32 imprinted gene cluster.

PubMed

Rosenfeld, Jill A; Fox, Joyce E; Descartes, Maria; Brewer, Fallon; Stroud, Tracy; Gorski, Jerome L; Upton, Sheila J; Moeschler, John B; Monteleone, Berrin; Neill, Nicholas J; Lamb, Allen N; Ballif, Blake C; Shaffer, Lisa G; Ravnan, J Britt

2015-02-01

Uniparental disomy (UPD) for imprinted chromosomes can cause abnormal phenotypes due to absent or overexpression of imprinted genes. UPD(14)pat causes a unique constellation of features including thoracic skeletal anomalies, polyhydramnios, placentomegaly, and limited survival; its hypothesized cause is overexpression of paternally expressed RTL1, due to absent regulatory effects of maternally expressed RTL1as. UPD(14)mat causes a milder condition with hypotonia, growth failure, and precocious puberty; its hypothesized cause is absence of paternally expressed DLK1. To more clearly establish how gains and losses of imprinted genes can cause disease, we report six individuals with copy number variations of the imprinted 14q32 region identified through clinical microarray-based comparative genomic hybridization. Three individuals presented with UPD(14)mat-like phenotypes (Temple syndrome) and had apparently de novo deletions spanning the imprinted region, including DLK1. One of these deletions was shown to be on the paternal chromosome. Two individuals with UPD(14)pat-like phenotypes had 122-154kb deletions on their maternal chromosomes that included RTL1as but not the differentially methylated regions that regulate imprinted gene expression, providing further support for RTL1 overexpression as a cause for the UPD(14)pat phenotype. The sixth individual is tetrasomic for a 1.7Mb segment, including the imprinted region, and presents with intellectual disability and seizures but lacks significant phenotypic overlap with either UPD(14) syndrome. Therefore, the 14q32 imprinted region is dosage sensitive, with deletions of different critical regions causing UPD(14)mat- and UPD(14)pat-like phenotypes, while copy gains are likely insufficient to recapitulate these phenotypes.

NADP+ Binding to the Regulatory Subunit of Methionine Adenosyltransferase II Increases Intersubunit Binding Affinity in the Hetero-Trimer

PubMed Central

Ortega, Rebeca; Martínez-Júlvez, Marta; Revilla-Guarinos, Ainhoa; Pérez-Pertejo, Yolanda; Velázquez-Campoy, Adrián; Sanz-Aparicio, Julia; Pajares, María A.

2012-01-01

Mammalian methionine adenosyltransferase II (MAT II) is the only hetero-oligomer in this family of enzymes that synthesize S-adenosylmethionine using methionine and ATP as substrates. Binding of regulatory β subunits and catalytic α2 dimers is known to increase the affinity for methionine, although scarce additional information about this interaction is available. This work reports the use of recombinant α2 and β subunits to produce oligomers showing kinetic parameters comparable to MAT II purified from several tissues. According to isothermal titration calorimetry data and densitometric scanning of the stained hetero-oligomer bands on denatured gels, the composition of these oligomers is that of a hetero-trimer with α2 dimers associated to single β subunits. Additionally, the regulatory subunit is able to bind NADP+ with a 1∶1 stoichiometry, the cofactor enhancing β to α2-dimer binding affinity. Mutants lacking residues involved in NADP+ binding and N-terminal truncations of the β subunit were able to oligomerize with α2-dimers, although the kinetic properties appeared altered. These data together suggest a role for both parts of the sequence in the regulatory role exerted by the β subunit on catalysis. Moreover, preparation of a structural model for the hetero-oligomer, using the available crystal data, allowed prediction of the regions involved in β to α2-dimer interaction. Finally, the implications that the presence of different N-terminals in the β subunit could have on MAT II behavior are discussed in light of the recent identification of several splicing forms of this subunit in hepatoma cells. PMID:23189196

Water flow and solute transport in floating fen root mats

NASA Astrophysics Data System (ADS)

Stofberg, Sija F.; EATM van der Zee, Sjoerd

2015-04-01

Floating fens are valuable wetlands, found in North-Western Europe, that are formed by floating root mats when old turf ponds are colonized by plants. These terrestrialization ecosystems are known for their biodiversity and the presence of rare plant species, and the root mats reveal different vegetation zones at a small scale. The vegetation zones are a result of strong gradients in abiotic conditions, including groundwater dynamics, nutrients and pH. To prevent irreversible drought effects such as land subsidence and mineralization of peat, water management involves import of water from elsewhere to maintain constant surface water levels. Imported water may have elevated levels of salinity during dry summers, and salt exposure may threaten the vegetation. To assess the risk of exposure of the rare plant species to salinity, the hydrology of such root mats must be understood. Physical properties of root mats have scarcely been investigated. We have measured soil characteristics, hydraulic conductivity, vertical root mat movement and groundwater dynamics in a floating root mat in the nature reserve Nieuwkoopse Plassen, in the Netherlands. The root mat mostly consists of roots and organic material, in which the soil has a high saturated water content, and strongly varies in its stage of decomposition. We have found a distinct negative correlation between degree of decomposition and hydraulic conductivity, similar to observations for bogs in the literature. Our results show that the relatively young, thin edge of the root mat that colonizes the surface water has a high hydraulic conductivity and floats in the surface water, resulting in very small groundwater fluctuations within the root mat. The older part of the root mat, that is connected to the deeper peat layers is hydrologically more isolated and the material has a lower conductivity. Here, the groundwater fluctuates strongly with atmospheric forcing. The zones of hydraulic properties and vegetation, appear to be very similar and likely functionally related. Our experimental field data were used for modelling water flow and solute transport in floating fens, using HYDRUS 2D. Fluctuations of surface water and root mat, as well as geometry and unsaturated zone parameters can have a major influence on groundwater fluctuations and the exchange between rain and surface water and the water in the root mats. In combination with the duration of salt pulses in surface water, and sensitivity of fen plants to salinity (Stofberg et al. 2014, submitted), risks for rare plants can be anticipated.

Insights into the Processing of Carbon by Early Microbial Ecosystems

NASA Technical Reports Server (NTRS)

DesMarais, D.; Bebout, B.; Carpenter, S.; Discipulo, S.; Londry, K.; Habicht, K.; Turk, K.

2003-01-01

Interactions between Earth and the biosphere that were crucial for early biological evolution also influenced substantially the processes that circulate C between its reservoirs in the atmosphere, ocean, crust and mantle. The C-13 C-12 values of crustal carbonates and organics have recorded changes both in biological discrimination and in the relative rates of burial of organics and carbonates. A full interpretation of these patterns needs further isotopic studies of microbial ecosystems and individual anaerobes. Thus we measured carbon isotope discrimination during autotrophic and heterotrophic growth of pure cultures of sulfate-reducing bacteria and archaea (SRB and SRA). Discrimination during CO2 assimilation is significantly larger than during heterotrophic growth on lactate or acetate. SRB grown lithoautotrophically consumed less than 3% of available CO2 and exhibited substantial discrimination, as follows: Desulfobacterium autotrophicum (alpha 1.0100 to 1.0123), Desulfobacter hydrogenophilus (alpha = 0.0138), and Desulfotomuculum acetoxidans (alpha = 1.0310). Mixotrophic growth of Desulfovibrio desulfuricans on acetate and CO2 resulted in biomass with delta C-13 composition intermediate to that of the substrates. We have recently extended these experiments to include the thermophilic SRA Archeoglobus spp. Ecological forces also influence isotopic discrimination. Accordingly, we quantified the flow of C and other constituents in modern marine cyanobacterial mats, whose ancestry extends back billions of years. Such ecosystem processes shaped the biosignatures that entered sediments and atmospheres. At Guerrero Negro, BCS, Mexico, we examined mats dominated by Microcoleus (subtidal) and Lyngbya (intertidal to supratidal) cyanobacteria. During 24 hour cycles, we observed the exchange of O2 and dissolved inorganic C (DIC) between mats and the overlying water. Microcoleus mats assimilated near-equal amounts of DIC during the day as they released at night, but Lyngbya mats typically showed net uptake of DIC over the diel cycle. Patterns of O2 daytime release and nighttime uptake mirrored these DIC trends in both mat types. Nighttime DIC effluxes from Microcoleus mats were equivalent in the presence versus absence of O2, whereas nighttime DIC effluxes from Lyngbya mats dropped markedly in the absence of O2. Thus aerobic diagenesis was more important in Lyngbya mats than in Microcoleus mats, perhaps because trapped O2 bubbles persist only in Lyngbya mats at night and thus sustain populations of aerbes. In both mat types, effluxes of H2, CH4 and short-chain fatty acids were much greater at night in the absence of 02, emphasizing the importance of fermentation. Differences observed between Microcoleus versus Lyngbya mats forecast differences in their microbial populations and in their patterns of gene expression.

High Areal Capacity Si/LiCoO 2 Batteries from Electrospun Composite Fiber Mats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Self, Ethan C.; Naguib, Michael; Ruther, Rose E.

Here, freestanding nanofiber mat Li-ion battery anodes containing Si nanoparticles, carbon black, and poly(acrylic acid) (Si/C/PAA) are prepared using electrospinning. The mats are compacted to a high fiber volume fraction (~0.85), and interfiber contacts are welded by exposing the mat to methanol vapor. A compacted+welded fiber mat anode containing 40 wt % Si exhibits high capacities of 1,484 mA h g -1 (3,500 mA h gmore » $$-1\\atop{Si}$$) at 0.1 C and 489 mAh g -1 at 1 C and good cycling stability (e.g., 73% capacity retention over 50 cycles). Post-mortem analysis of the fiber mats shows that the overall electrode structure is preserved during cycling. Whereas many nanostructured Si anodes are hindered by their low active material loadings and densities, thick, densely packed Si/C/PAA fiber mat anodes reported here have high areal and volumetric capacities (e.g., 4.5 mA h cm -2 and 750 mA h cm -3, respectively). A full cell containing an electrospun Si/C/PAA anode and electrospun LiCoO 2-based cathode has a high specific energy density of 270 Wh kg -1. The excellent performance of the electrospun Si/C/PAA fiber mat anodes is attributed to the: (i) PAA binder which interacts with the SiO x surface of Si nanoparticles and (ii) high material loading, high fiber volume fraction, and welded interfiber contacts of the electrospun mats« less

Ignavibacterium album gen. nov., sp. nov., a moderately thermophilic anaerobic bacterium isolated from microbial mats at a terrestrial hot spring and proposal of Ignavibacteria classis nov., for a novel lineage at the periphery of green sulfur bacteria.

PubMed

Iino, Takao; Mori, Koji; Uchino, Yoshihito; Nakagawa, Tatsunori; Harayama, Shigeaki; Suzuki, Ken-Ichiro

2010-06-01

A moderately thermophilic chemoheterotrophic bacterium, strain Mat9-16(T), was isolated from microbial mats developed in hot spring water streams from Yumata, Nagano, Japan. Cells of strain Mat9-16(T) were strictly anaerobic, Gram-stain-negative, non-sporulating, non-motile and short to long rods (2.0-15.5 mum in length). Strain Mat9-16(T) grew fermentatively with optimum growth at 45 degrees C, pH 7.0-7.5 and 1 % NaCl (w/v). Phylogenetic analysis based on the 16S rRNA gene revealed that strain Mat9-16(T) was affiliated with an uncultivated lineage, and the nearest cultivated neighbours were green sulfur bacteria belonging to the class Chlorobea with 77-83 % sequence similarity. However, strain Mat9-16(T) could not grow phototrophically and did not possess light-harvesting structures, morphologically and genetically, such as the chlorosomes of green sulfur bacteria. On the basis of phenotypic features and phylogenetic position, a novel genus and species are proposed for strain Mat9-16(T), to be named Ignavibacterium album gen. nov., sp. nov. (=NBRC 101810(T) =DSM 19864(T)). We also propose to place the cultivated bacterial lineage accommodating the sole representative Mat9-16(T) in a novel class, Ignavibacteria classis nov. In addition, we present a formal description of the phylum-level taxon 'Chlorobi' as Chlorobi phyl. nov.

Production and Consumption of Hydrogen in Hot Spring Microbial Mats Dominated by a Filamentous Anoxygenic Photosynthetic Bacterium

PubMed Central

Otaki, Hiroyo; Everroad, R. Craig; Matsuura, Katsumi; Haruta, Shin

2012-01-01

Microbial mats containing the filamentous anoxygenic photosynthetic bacterium Chloroflexus aggregans develop at Nakabusa hot spring in Japan. Under anaerobic conditions in these mats, interspecies interaction between sulfate-reducing bacteria as sulfide producers and C. aggregans as a sulfide consumer has been proposed to constitute a sulfur cycle; however, the electron donor utilized for microbial sulfide production at Nakabusa remains to be identified. In order to determine this electron donor and its source, ex situ experimental incubation of mats was explored. In the presence of molybdate, which inhibits biological sulfate reduction, hydrogen gas was released from mat samples, indicating that this hydrogen is normally consumed as an electron donor by sulfate-reducing bacteria. Hydrogen production decreased under illumination, indicating that C. aggregans also functions as a hydrogen consumer. Small amounts of hydrogen may have also been consumed for sulfur reduction. Clone library analysis of 16S rRNA genes amplified from the mats indicated the existence of several species of hydrogen-producing fermentative bacteria. Among them, the most dominant fermenter, Fervidobacterium sp., was successfully isolated. This isolate produced hydrogen through the fermentation of organic carbon. Dispersion of microbial cells in the mats resulted in hydrogen production without the addition of molybdate, suggesting that simultaneous production and consumption of hydrogen in the mats requires dense packing of cells. We propose a cyclic electron flow within the microbial mats, i.e., electron flow occurs through three elements: S (elemental sulfur, sulfide, sulfate), C (carbon dioxide, organic carbon) and H (di-hydrogen, protons). PMID:22446313

Sedimentary Parameters Controlling Occurrence and Preservation of Microbial Mats in Siliciclastic Depositional Systems

NASA Technical Reports Server (NTRS)

Noffke, Nora; Knoll, Andrew H.

2001-01-01

Shallow-marine, siliciclastic depositional systems are governed by physical sedimentary processes. Mineral precipitation or penecontemporaneous cementation play minor roles. Today, coastal siliciclastic environments may be colonized by a variety of epibenthic, mat-forming cyanobacteria. Studies on microbial mats showed that they are not randomly distributed in modern tidal environments. Distribution and abundancy is mainly function of a particular sedimentary facies. Fine-grained sands composed of "clear" (translucent) quartz particles constitute preferred substrates for cyanobacteria. Mat-builders also favor sites characterized by moderate hydrodynamic flow regimes, which permit biomass enrichment and construction of mat fabrics without lethal burial of mat populations by fine sediments. A comparable facies relationship can be observed in ancient siliciclastic shelf successions from the terminal Neoproterozoic Nama Group, Namibia. Wrinkle structures that record microbial mats are present but sparsely distributed in mid- to inner shelf sandstones of the Nudaus Formation. The sporadic distribution of these structures reflects both the narrow ecological window that governs mat development and the distinctive taphonomic conditions needed to preserve the structures. These observations caution that statements about changing mat abundance across the Proterozoic-Cambrian boundary must be firmly rooted in paleoenvironmental and taphonomic analysis. Understanding the factors that influence the formation and preservation of microbial structures in siliciclastic regimes can facilitate exploration for biological signatures in Earth's oldest rocks. Moreover, insofar as these structures can be preserved on bedding surfaces and are not easily mimicked by physical processes, they constitute a set of biological markers that can be searched for on Mars by remotely controlled rovers.

High Areal Capacity Si/LiCoO 2 Batteries from Electrospun Composite Fiber Mats

DOE PAGES

Self, Ethan C.; Naguib, Michael; Ruther, Rose E.; ...

2017-03-24

Here, freestanding nanofiber mat Li-ion battery anodes containing Si nanoparticles, carbon black, and poly(acrylic acid) (Si/C/PAA) are prepared using electrospinning. The mats are compacted to a high fiber volume fraction (~0.85), and interfiber contacts are welded by exposing the mat to methanol vapor. A compacted+welded fiber mat anode containing 40 wt % Si exhibits high capacities of 1,484 mA h g -1 (3,500 mA h gmore » $$-1\\atop{Si}$$) at 0.1 C and 489 mAh g -1 at 1 C and good cycling stability (e.g., 73% capacity retention over 50 cycles). Post-mortem analysis of the fiber mats shows that the overall electrode structure is preserved during cycling. Whereas many nanostructured Si anodes are hindered by their low active material loadings and densities, thick, densely packed Si/C/PAA fiber mat anodes reported here have high areal and volumetric capacities (e.g., 4.5 mA h cm -2 and 750 mA h cm -3, respectively). A full cell containing an electrospun Si/C/PAA anode and electrospun LiCoO 2-based cathode has a high specific energy density of 270 Wh kg -1. The excellent performance of the electrospun Si/C/PAA fiber mat anodes is attributed to the: (i) PAA binder which interacts with the SiO x surface of Si nanoparticles and (ii) high material loading, high fiber volume fraction, and welded interfiber contacts of the electrospun mats« less

Ethanol metabolism, oxidative stress, and endoplasmic reticulum stress responses in the lungs of hepatic alcohol dehydrogenase deficient deer mice after chronic ethanol feeding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaphalia, Lata; Boroumand, Nahal; Hyunsu, Ju

Consumption and over-consumption of alcoholic beverages are well-recognized contributors to a variety of pulmonary disorders, even in the absence of intoxication. The mechanisms by which alcohol (ethanol) may produce disease include oxidative stress and prolonged endoplasmic reticulum (ER) stress. Many aspects of these processes remain incompletely understood due to a lack of a suitable animal model. Chronic alcohol over-consumption reduces hepatic alcohol dehydrogenase (ADH), the principal canonical metabolic pathway of ethanol oxidation. We therefore modeled this situation using hepatic ADH-deficient deer mice fed 3.5% ethanol daily for 3 months. Blood ethanol concentration was 180 mg% in ethanol fed mice, comparedmore » to < 1.0% in the controls. Acetaldehyde (oxidative metabolite of ethanol) was minimally, but significantly increased in ethanol-fed vs. pair-fed control mice. Total fatty acid ethyl esters (FAEEs, nonoxidative metabolites of ethanol) were 47.6 μg/g in the lungs of ethanol-fed mice as compared to 1.5 μg/g in pair-fed controls. Histological and immunohistological evaluation showed perivascular and peribronchiolar lymphocytic infiltration, and significant oxidative injury, in the lungs of ethanol-fed mice compared to pair-fed controls. Several fold increases for cytochrome P450 2E1, caspase 8 and caspase 3 found in the lungs of ethanol-fed mice as compared to pair-fed controls suggest role of oxidative stress in ethanol-induced lung injury. ER stress and unfolded protein response signaling were also significantly increased in the lungs of ethanol-fed mice. Surprisingly, no significant activation of inositol-requiring enzyme-1α and spliced XBP1 was observed indicating a lack of activation of corrective mechanisms to reinstate ER homeostasis. The data suggest that oxidative stress and prolonged ER stress, coupled with formation and accumulation of cytotoxic FAEEs may contribute to the pathogenesis of alcoholic lung disease. - Highlights: • Chronic ethanol feeding causes oxidative stress, ER stress and inflammation in lungs of ADH– deer mice. • Chronic ethanol feeding generates FAEEs (nonoxidative metabolites of ethanol) in lungs of ADH– deer mice. • Chronic ethanol feeding induces CYP2E1 in the lungs of ADH– deer mice. • Lack of ER homeostasis due to a prolonged ethanol feeding could trigger inflammation.« less

CYP2E1-dependent and leptin-mediated hepatic CD57 expression on CD8 + T cells aid progression of environment-linked nonalcoholic steatohepatitis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seth, Ratanesh Kumar; Das, Suvarthi; Kumar, Ashutosh

2014-01-01

Environmental toxins induce a novel CYP2E1/leptin signaling axis in liver. This in turn activates a poorly characterized innate immune response that contributes to nonalcoholic steatohepatitis (NASH) progression. To identify the relevant subsets of T-lymphocytes in CYP2E1-dependent, environment-linked NASH, we utilized a model of diet induced obese (DIO) mice that are chronically exposed to bromodichloromethane. Mice deficient in CYP2E1, leptin (ob/ob mice), or both T and B cells (Pfp/Rag2 double knockout (KO) mice) were used to delineate the role of each of these factors in metabolic oxidative stress-induced T cell activation. Results revealed that elevated levels of lipid peroxidation, tyrosyl radicalmore » formation, mitochondrial tyrosine nitration and hepatic leptin as a consequence of metabolic oxidative stress caused increased levels of hepatic CD57, a marker of peripheral blood lymphocytes including NKT cells. CD8 + CD57 + cytotoxic T cells but not CD4 + CD57 + cells were significantly decreased in mice lacking CYP2E1 and leptin. There was a significant increase in the levels of T cell cytokines IL-2, IL-1β, and IFN-γ in bromodichloromethane exposed DIO mice but not in mice that lacked CYP2E1, leptin or T and B cells. Apoptosis as evidenced by TUNEL assay and levels of cleaved caspase-3 was significantly lower in leptin and Pfp/Rag2 KO mice and highly correlated with protection from NASH. The results described above suggest that higher levels of oxidative stress-induced leptin mediated CD8 + CD57 + T cells play an important role in the development of NASH. It also provides a novel insight of immune dysregulation and may be a key biomarker in NASH. - Highlights: • Metabolic oxidative stress caused increased levels of hepatic CD57 expression. • CD8+ CD57+ cytotoxic T cells were decreased in mice lacking CYP2E1 and leptin. • There was a significant increase in T cell cytokines in toxin-treated mice. • Apoptosis was significantly lower in leptin and Pfp/Rag2 KO mice. • Leptin mediated CD8+CD57+ T cells play an important role in NASH.« less

Black Mats, Spring-Fed Streams, and Late-Glacial-Age Recharge in the Southern Great Basin

USGS Publications Warehouse

Quade, Jay; Forester, R.M.; Pratt, W.L.; Carter, C.

1998-01-01

Black mats are prominent features of the late Pleistocene and Holocene stratigraphic record in the southern Great Basin. Faunal, geochemical, and sedimentological evidence shows that the black mats formed in several microenvironments related to spring discharge, ranging from wet meadows to shallow ponds. Small land snails such as Gastrocopta tappaniana and Vertigo berryi are the most common mollusk taxa present. Semiaquatic and aquatic taxa are less abundant and include Catinellids, Fossaria parva, Gyraulus parvus, and others living today in and around perennial seeps and ponds. The ostracodes Cypridopsis okeechobi and Scottia tumida, typical of seeps and low-discharge springs today, as well as other taxa typical of springs and wetlands, are common in the black mats. Several new species that lived in the saturated subsurface also are present, but lacustrine ostracodes are absent. The ??13C values of organic matter in the black mats range from -12 to -26???, reflecting contributions of tissue from both C3 (sedges, most shrubs and trees) and C4 (saltbush, saltgrass) plants. Carbon-14 dates on the humate fraction of 55 black mats fall between 11,800 to 6300 and 2300 14C yr B.P. to modern. The total absence of mats in our sample between 6300 and 2300 14C yr B.P. likely reflects increased aridity associated with the mid-Holocene Altithermal. The oldest black mats date to 11,800-11,600 14C yr B.P., and the peak in the 14C black mat distribution falls at ???10,000 14C yr B.P. As the formation of black mats is spring related, their abundance reflects refilling of valley aquifers starting no later than 11,800 and peaking after 11,000 14C yrB.P. Reactivation of spring-fed channels shortly before 11,200 14C yr B.P. is also apparent in the stratigraphic records from the Las Vegas and Pahrump Valleys. This age distribution suggests that black mats and related spring-fed channels in part may have formed in response to Younger Dryas (YD)-age recharge in the region. However, the inception of black mat formation precedes that of the YD by at least 400 14C yr, and hydrological change is gradual, not rapid. ?? 1998 University of Washington.

Context, Biogeochemistry, and Morphology of Diverse and Spatially Extensive Microbial Mats, Little Ambergris Cay, Turks and Caicos Islands, B.W.I.

NASA Astrophysics Data System (ADS)

Present, T. M.; Trower, L.; Stein, N.; Alleon, J.; Bahniuk, A.; Gomes, M. L.; Lingappa, U.; Metcalfe, K.; Orzechowski, E. A.; Riedman, L. A.; Sanders, C. B.; Morris, D. K.; O'Reilly, S.; Sibert, E. C.; Thorpe, M.; Tarika, M.; Fischer, W. W.; Knoll, A. H.; Grotzinger, J. P.

2017-12-01

Little Ambergris Cay (21.3° N, 71.7° W) was the site of an integrated geobiological study conducted in July 2016 and August 2017. The cay ( 6 km x 1.6 km) is developed on a broad bank influenced by strong easterly trade winds (avg. 7.5 m/s), where convergent ooid shoals culminate in a linear shoal extending almost 25 km westward from the cay. Lithified upper shoreface to eolian ooid grainstones form a 2 m high bedrock rim that protects an extensive interior tidal marsh with well-developed microbial mats. Local breaches in the rim allow tidal flows to inundate interior bays floored by microbial mats. Three mat types were observed based on texture: dark toned "blister mat" that flanks the bays where they intersect with the bedrock rim; light-toned "polygonal mat" that covers broad tracts of the bay and is exposed at low tide; and lighter-toned "EPS mat" that is generally submerged even at low tide. The millimeter-to decimeter-thick layered mats overlie laterally extensive ooid sands, generally unlithified except for a few hardgrounds. The mats and underlying sediments were sampled by vibracoring, push coring, and piezometers. Biogeochemical analyses include groundwater salinity, pH, DIC, alkalinity, cation composition, DNA content, photosynthetic efficiency, C and S isotope composition, lipid biomarkers, and taphonomic state. Groundwater and interstitial water chemical analyses were integrated with hydrologic observations of tidal channels' level and flow. Visible light UAV images from 350 m standoff distance were processed to generate a 15 cm/pixel mosaic of the island that was used in combination with a DGPS survey, multispectral Landsat images (m-scale resolution) and Worldview satellite images (30 cm resolution) to map the island's topography, mats, and sedimentologic facies. A UAV-based VNIR hyperspectral camera was used to quantify pigment concentrations in the mats at cm-resolution over decameter scales. Sub-cm-scale bed textures, including those expressed by the different microbial mats, were quantified from images captured with 5-20 m standoff. The thickness of the Holocene sediment fill (0 to >2m) was estimated using core data and a depth probe. These data inform the preservation of microbial textures in grain-dominated carbonate facies and provide analogs for ancient microbial laminites.

Black Mats, Spring-Fed Streams, and Late-Glacial-Age Recharge in the Southern Great Basin

NASA Astrophysics Data System (ADS)

Quade, Jay; Forester, Richard M.; Pratt, William L.; Carter, Claire

1998-03-01

Black mats are prominent features of the late Pleistocene and Holocene stratigraphic record in the southern Great Basin. Faunal, geochemical, and sedimentological evidence shows that the black mats formed in several microenvironments related to spring discharge, ranging from wet meadows to shallow ponds. Small land snails such as Gastrocopta tappanianaand Vertigo berryiare the most common mollusk taxa present. Semiaquatic and aquatic taxa are less abundant and include Catinellids, Fossaria parva, Gyraulus parvus,and others living today in and around perennial seeps and ponds. The ostracodes Cypridopsis okeechobiand Scottia tumida,typical of seeps and low-discharge springs today, as well as other taxa typical of springs and wetlands, are common in the black mats. Several new species that lived in the saturated subsurface also are present, but lacustrine ostracodes are absent. The δ 13C values of organic matter in the black mats range from -12 to -26‰, reflecting contributions of tissue from both C 3(sedges, most shrubs and trees) and C 4(saltbush, saltgrass) plants. Carbon-14 dates on the humate fraction of 55 black mats fall between 11,800 to 6300 and 2300 14C yr B.P. to modern. The total absence of mats in our sample between 6300 and 2300 14C yr B.P. likely reflects increased aridity associated with the mid-Holocene Altithermal. The oldest black mats date to 11,800-11,600 14C yr B.P., and the peak in the 14C black mat distribution falls at ˜10,000 14C yr B.P. As the formation of black mats is spring related, their abundance reflects refilling of valley aquifers starting no later than 11,800 and peaking after 11,000 14C yr B.P. Reactivation of spring-fed channels shortly before 11,200 14C yr B.P. is also apparent in the stratigraphic records from the Las Vegas and Pahrump Valleys. This age distribution suggests that black mats and related spring-fed channels in part may have formed in response to Younger Dryas (YD)-age recharge in the region. However, the inception of black mat formation precedes that of the YD by at least 400 14C yr, and hydrological change is gradual, not rapid.

Development of mice without Cip/Kip CDK inhibitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tateishi, Yuki; Matsumoto, Akinobu; Kanie, Tomoharu

2012-10-19

Highlights: Black-Right-Pointing-Pointer Mice lacking Cip/Kip CKIs (p21, p27, and p57) survive until embryonic day 13.5. Black-Right-Pointing-Pointer Proliferation of MEFs lacking all three Cip/Kip CKIs appears unexpectedly normal. Black-Right-Pointing-Pointer CDK2 kinase activity of the triple mutant MEFs is increased in G0 phase. -- Abstract: Timely exit of cells from the cell cycle is essential for proper cell differentiation during embryogenesis. Cyclin-dependent kinase (CDK) inhibitors (CKIs) of the Cip/Kip family (p21, p27, and p57) are negative regulators of cell cycle progression and are thought to be essential for development. However, the extent of functional redundancy among Cip/Kip family members has remained largelymore » unknown. We have now generated mice that lack all three Cip/Kip CKIs (TKO mice) and compared them with those lacking each possible pair of these proteins (DKO mice). We found that the TKO embryos develop normally until midgestation but die around embryonic day (E) 13.5, slightly earlier than p27/p57 DKO embryos. The TKO embryos manifested morphological abnormalities as well as increased rates of cell proliferation and apoptosis in the placenta and lens that were essentially indistinguishable from those of p27/p57 DKO mice. Unexpectedly, the proliferation rate and cell cycle profile of mouse embryonic fibroblasts (MEFs) lacking all three Cip/Kip CKIs did not differ substantially from those of control MEFs. The abundance and kinase activity of CDK2 were markedly increased, whereas CDK4 activity and cyclin D1 abundance were decreased, in both p27/p57 DKO and TKO MEFs during progression from G{sub 0} to S phase compared with those in control MEFs. The extents of the increase in CDK2 activity and the decrease in CDK4 activity and cyclin D1 abundance were greater in TKO MEFs than in p27/p57 DKO MEFs. These results suggest that p27 and p57 play an essential role in mouse development after midgestation, and that p21 plays only an auxiliary role in normal development (although it is thought to be a key player in the response to DNA damage).« less

Differential splicing and glycosylation of Apoer2 alters synaptic plasticity and fear learning.

PubMed

Wasser, Catherine R; Masiulis, Irene; Durakoglugil, Murat S; Lane-Donovan, Courtney; Xian, Xunde; Beffert, Uwe; Agarwala, Anandita; Hammer, Robert E; Herz, Joachim

2014-11-25

Apoer2 is an essential receptor in the central nervous system that binds to the apolipoprotein ApoE. Various splice variants of Apoer2 are produced. We showed that Apoer2 lacking exon 16, which encodes the O-linked sugar (OLS) domain, altered the proteolytic processing and abundance of Apoer2 in cells and synapse number and function in mice. In cultured cells expressing this splice variant, extracellular cleavage of OLS-deficient Apoer2 was reduced, consequently preventing γ-secretase-dependent release of the intracellular domain of Apoer2. Mice expressing Apoer2 lacking the OLS domain had increased Apoer2 abundance in the brain, hippocampal spine density, and glutamate receptor abundance, but decreased synaptic efficacy. Mice expressing a form of Apoer2 lacking the OLS domain and containing an alternatively spliced cytoplasmic tail region that promotes glutamate receptor signaling showed enhanced hippocampal long-term potentiation (LTP), a phenomenon associated with learning and memory. However, these mice did not display enhanced spatial learning in the Morris water maze, and cued fear conditioning was reduced. Reducing the expression of the mutant Apoer2 allele so that the abundance of the protein was similar to that of Apoer2 in wild-type mice normalized spine density, hippocampal LTP, and cued fear learning. These findings demonstrated a role for ApoE receptors as regulators of synaptic glutamate receptor activity and established differential receptor glycosylation as a potential regulator of synaptic function and memory. Copyright © 2014, American Association for the Advancement of Science.

Differential splicing and glycosylation of Apoer2 alters synaptic plasticity and fear learning

PubMed Central

Wasser, Catherine R.; Masiulis, Irene; Durakoglugil, Murat S.; Lane-Donovan, Courtney; Xian, Xunde; Beffert, Uwe; Agarwala, Anandita; Hammer, Robert E.; Herz, Joachim

2015-01-01

Apoer2 is an essential receptor in the central nervous system that binds to the apolipoprotein ApoE. Various splice variants of Apoer2 are produced. We showed that Apoer2 lacking exon 16, which encodes the O-linked sugar (OLS) domain, altered the proteolytic processing and abundance of Apoer2 in cells and synapse number and function in mice. In cultured cells expressing this splice variant, extracellular cleavage of OLS-deficient Apoer2 was reduced, consequently preventing γ-secretase-dependent release of the intracellular domain of Apoer2. Mice expressing Apoer2 lacking the OLS domain had increased Apoer2 abundance in the brain, hippocampal spine density, and glutamate receptor abundance, but decreased synaptic efficacy. Mice expressing a form of Apoer2 lacking the OLS domain and containing an alternatively spliced cytoplasmic tail region that promotes glutamate receptor signaling showed enhanced hippocampal long-term potentiation (LTP), a phenomenon associated with learning and memory. However, these mice did not display enhanced spatial learning in the Morris water maze, and cued fear conditioning was reduced. Reducing the expression of the mutant Apoer2 allele so that the abundance of the protein was similar to that of Apoer2 in wild-type mice normalized spine density, hippocampal LTP, and cued fear learning. These findings demonstrated a role for ApoE receptors as regulators of synaptic glutamate receptor activity and established differential receptor glycosylation as a potential regulator of synaptic function and memory. PMID:25429077

Microbial mats and the early evolution of life

NASA Technical Reports Server (NTRS)

Des Marais, D. J.

1990-01-01

Microbial mats have descended from perhaps the oldest and most widespread biological communities known. Mats harbor microbes that are crucial for studies of bacterial phylogeny and physiology. They illustrate how several oxygen-sensitive biochemical processes have adapted to oxygen, and they show how life adapted to dry land long before the rise of plants. The search for the earliest grazing protists and metazoa in stromatolites is aided by observations of mats: in them, organic compounds characteristic of ancient photosynthetic protists can be identified. Recent mat studies suggest that the 13C/12C increase observed over geological time in stromatolitic organic matter was driven at least in part by a long-term decline in atmospheric carbon dioxide levels.

The role of simulation in the development and flight test of the HiMAT vehicle

NASA Technical Reports Server (NTRS)

Evans, M. B.; Schilling, L. J.

1984-01-01

Real time simulations have been essential in the flight test program of the highly maneuverable aircraft technology (HiMAT) remotely piloted research vehicle at NASA Ames Research Center's Dryden Flight Research Facility. The HiMAT project makes extensive use of simulations in design, development, and qualification for flight, pilot training, and flight planning. Four distinct simulations, each with varying amounts of hardware in the loop, were developed for the HiMAT project. The use of simulations in detecting anomalous behavior of the flight software and hardware at the various stages of development, verification, and validation has been the key to flight qualification of the HiMAT vehicle.

BIOGEOCHEMICAL STUDIES OF PHOTOSYNTHETIC MICROBIAL MATS AND THEIR BIOTA

NASA Technical Reports Server (NTRS)

DesMarais, David; Discipulo, M.; Turk, K.; Londry, K. L.

2005-01-01

Photosynthetic microbial mats offer an opportunity to define holistic functionality at the millimeter scale. At the same time. their biogeochemistry contributes to environmental processes on a planetary scale. These mats are possibly direct descendents of the most ancient biological communities; communities in which oxygenic photosynthesis might have been invented. Mats provide one of the best natural systems to study how microbial populations associate to control dynamic biogeochemical gradients. These are self- sustaining, complete ecosystems in which light energy absorbed over a dial (24 hour) cycle drives the synthesis of spatially-organized, diverse biomass. Tightly-coupled microorganisms in the mat have specialized metabolisms that catalyze transformations of carbon, nitrogen, sulfur, and a host of other elements.

Increased consumption of ethanol and sugar water in mice lacking the dopamine D2 long receptor

PubMed Central

Bulwa, Zachary B.; Sharlin, Jordan A.; Clark, Peter J.; Bhattacharya, Tushar K.; Kilby, Chessa N.; Wang, Yanyan; Rhodes, Justin S.

2011-01-01

Individual differences in dopamine D2 receptor (D2R) expression in the brain are thought to influence motivation and reinforcement for ethanol and other rewards. D2R exists in two isoforms, D2 long (D2LR) and D2 short (D2SR), produced by alternative splicing of the same gene. The relative contributions of D2LR versus D2SR to ethanol and sugar water drinking are not known. Genetic engineering was used to produce a line of knockout (KO) mice that lack D2LR and consequently have increased expression of D2SR. KO and wild-type (WT) mice of both sexes were tested for intake of 20% ethanol, 10% sugar water and plain tap water using established drinking-in-the-dark procedures. Mice were also tested for effects of the D2 antagonist eticlopride on intake of ethanol to determine whether KO responses were caused by lack of D2LR or over-representation of D2SR. Locomotor activity on running wheels and in cages without wheels was also measured for comparison. D2L KO mice drank significantly more ethanol than WT in both sexes. KO mice drank more sugar water than WT in females but not in males. Eticlopride dose- dependently decreased ethanol intake in all groups except male KO. KO mice were less physically active than WT in cages with or without running wheels. Results suggest that over-representation of D2SR contributes to increased intake of ethanol in the KO mice. Decreasing wheel running and general levels of physical activity in the KO mice rules out the possibility that higher intake results from higher motor activity. Results extend the literature implicating altered expression of D2R in risk for addiction by delineating the contribution of individual D2R isoforms. These findings suggest that D2LR and D2SR play differential roles in consumption of alcohol and sugar rewards. PMID:21803530

Increased consumption of ethanol and sugar water in mice lacking the dopamine D2 long receptor.

PubMed

Bulwa, Zachary B; Sharlin, Jordan A; Clark, Peter J; Bhattacharya, Tushar K; Kilby, Chessa N; Wang, Yanyan; Rhodes, Justin S

2011-11-01

Individual differences in dopamine D2 receptor (D2R) expression in the brain are thought to influence motivation and reinforcement for ethanol and other rewards. D2R exists in two isoforms, D2 long (D2LR) and D2 short (D2SR), produced by alternative splicing of the same gene. The relative contributions of D2LR versus D2SR to ethanol and sugar water drinking are not known. Genetic engineering was used to produce a line of knockout (KO) mice that lack D2LR and consequently have increased expression of D2SR. KO and wild-type (WT) mice of both sexes were tested for intake of 20% ethanol, 10% sugar water and plain tap water using established drinking-in-the-dark procedures. Mice were also tested for effects of the D2 antagonist eticlopride on intake of ethanol to determine whether KO responses were caused by lack of D2LR or overrepresentation of D2SR. Locomotor activity on running wheels and in cages without wheels was also measured for comparison. D2L KO mice drank significantly more ethanol than WT in both sexes. KO mice drank more sugar water than WT in females but not in males. Eticlopride dose dependently decreased ethanol intake in all groups except male KO. KO mice were less physically active than WT in cages with or without running wheels. Results suggest that overrepresentation of D2SR contributes to increased intake of ethanol in the KO mice. Decreasing wheel running and general levels of physical activity in the KO mice rules out the possibility that higher intake results from higher motor activity. Results extend the literature implicating altered expression of D2R in risk for addiction by delineating the contribution of individual D2R isoforms. These findings suggest that D2LR and D2SR play differential roles in consumption of alcohol and sugar rewards. Copyright © 2011 Elsevier Inc. All rights reserved.

Long-term high-fat feeding induces greater fat storage in mice lacking UCP3.

PubMed

Costford, Sheila R; Chaudhry, Shehla N; Crawford, Sean A; Salkhordeh, Mahmoud; Harper, Mary-Ellen

2008-11-01

Uncoupling protein-3 (UCP3) is a mitochondrial inner-membrane protein highly expressed in skeletal muscle. While UCP3's function is still unknown, it has been hypothesized to act as a fatty acid (FA) anion exporter, protecting mitochondria against lipid peroxidation and/or facilitating FA oxidation. The aim of this study was to determine the effects of long-term feeding of a 45% fat diet on whole body indicators of muscle metabolism in congenic C57BL/6 mice that were either lacking UCP3 (Ucp3(-/-)) or had a transgenically induced approximately twofold increase in UCP3 levels (UCP3tg). Mice were fed the high-fat (HF) diet for a period of either 4 or 8 mo immediately following weaning. After long-term HF feeding, UCP3tg mice weighed an average of 15% less than wild-type mice (P < 0.05) and were 20% less metabolically efficient than both wild-type and Ucp3(-/-) mice (P < 0.01). Additionally, wild-type mice had 21% lower, whereas UCP3tg mice had 36% lower, levels of adiposity compared with Ucp3(-/-) mice (P < 0.05 and P < 0.001, respectively), indicating a protective effect of UCP3 against fat gain. No differences in whole body oxygen consumption were detected following long-term HF feeding. Glucose and insulin tolerance tests revealed that both the UCP3tg and Ucp3(-/-) mice were more glucose tolerant and insulin sensitive compared with wild-type mice after short-term HF feeding, but this protection was not maintained in the long term. Findings indicate that UCP3 is involved in protection from fat gain induced by long-term HF feeding, but not in protection from insulin resistance.

Lack of tau proteins rescues neuronal cell death and decreases amyloidogenic processing of APP in APP/PS1 mice.

PubMed

Leroy, Karelle; Ando, Kunie; Laporte, Vincent; Dedecker, Robert; Suain, Valérie; Authelet, Michèle; Héraud, Céline; Pierrot, Nathalie; Yilmaz, Zehra; Octave, Jean-Noël; Brion, Jean-Pierre

2012-12-01

Lack of tau expression has been reported to protect against excitotoxicity and to prevent memory deficits in mice expressing mutant amyloid precursor protein (APP) identified in familial Alzheimer disease. In APP mice, mutant presenilin 1 (PS1) enhances generation of Aβ42 and inhibits cell survival pathways. It is unknown whether the deficient phenotype induced by concomitant expression of mutant PS1 is rescued by absence of tau. In this study, we have analyzed the effect of tau deletion in mice expressing mutant APP and PS1. Although APP/PS1/tau(+/+) mice had a reduced survival, developed spatial memory deficits at 6 months and motor impairments at 12 months, these deficits were rescued in APP/PS1/tau(-/-) mice. Neuronal loss and synaptic loss in APP/PS1/tau(+/+) mice were rescued in the APP/PS1/tau(-/-) mice. The amyloid plaque burden was decreased by roughly 50% in the cortex and the spinal cord of the APP/PS1/tau(-/-) mice. The levels of soluble and insoluble Aβ40 and Aβ42, and the Aβ42/Aβ40 ratio were reduced in APP/PS1/tau(-/-) mice. Levels of phosphorylated APP, of β-C-terminal fragments (CTFs), and of β-secretase 1 (BACE1) were also reduced, suggesting that β-secretase cleavage of APP was reduced in APP/PS1/tau(-/-) mice. Our results indicate that tau deletion had a protective effect against amyloid induced toxicity even in the presence of mutant PS1 and reduced the production of Aβ. Copyright © 2012 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Perception of sweet taste is important for voluntary alcohol consumption in mice.

PubMed

Blednov, Y A; Walker, D; Martinez, M; Levine, M; Damak, S; Margolskee, R F

2008-02-01

To directly evaluate the association between taste perception and alcohol intake, we used three different mutant mice, each lacking a gene expressed in taste buds and critical to taste transduction: alpha-gustducin (Gnat3), Tas1r3 or Trpm5. Null mutant mice lacking any of these three genes showed lower preference score for alcohol and consumed less alcohol in a two-bottle choice test, as compared with wild-type littermates. These null mice also showed lower preference score for saccharin solutions than did wild-type littermates. In contrast, avoidance of quinine solutions was less in Gnat3 or Trpm5 knockout mice than in wild-type mice, whereas Tas1r3 null mice were not different from wild type in their response to quinine solutions. There were no differences in null vs. wild-type mice in their consumption of sodium chloride solutions. To determine the cause for reduction of ethanol intake, we studied other ethanol-induced behaviors known to be related to alcohol consumption. There were no differences between null and wild-type mice in ethanol-induced loss of righting reflex, severity of acute ethanol withdrawal or conditioned place preference for ethanol. Weaker conditioned taste aversion (CTA) to alcohol in null mice may have been caused by weaker rewarding value of the conditioned stimulus (saccharin). When saccharin was replaced by sodium chloride, no differences in CTA to alcohol between knockout and wild-type mice were seen. Thus, deletion of any one of three different genes involved in detection of sweet taste leads to a substantial reduction of alcohol intake without any changes in pharmacological actions of ethanol.

Activation of PPARα decreases bile acids in livers of female mice while maintaining bile flow and biliary bile acid excretion.

PubMed

Zhang, Youcai; Lickteig, Andrew J; Csanaky, Iván L; Klaassen, Curtis D

2018-01-01

Fibrates are hypolipidemic drugs that act as activators of peroxisome proliferator-activated receptor α (PPARα). In both humans and rodents, females were reported to be less responsive to fibrates than males. Previous studies on fibrates and PPARα usually involved male mice, but little has been done in females. The present study aimed to provide the first comprehensive analysis of the effects of clofibrate (CLOF) and PPARα on bile acid (BA) homeostasis in female mice. Study in WT male mice showed that a 4-day CLOF treatment increased liver weight, bile flow, and biliary BA excretion, but decreased total BAs in both serum and liver. In contrast, WT female mice were less susceptible to these CLOF-mediated responses observed in males. In WT female mice, CLOF decreased total BAs in the liver, but had little effect on the mRNAs of hepatic BA-related genes. Next, a comparative analysis between WT and PPARα-null female mice showed that lack of PPARα in female mice decreased total BAs in serum, but had little effect on total BAs in liver or bile. However, lack of PPARα in female mice increased mRNAs of BA synthetic enzymes (Cyp7a1, Cyp8b1, Cyp27a1, and Cyp7b1) and transporters (Ntcp, Oatp1a1, Oatp1b2, and Mrp3). Furthermore, the increase of Cyp7a1 in PPARα-null female mice was associated with an increase in liver Fxr-Shp-Lrh-1 signaling. In conclusion, female mice are resistant to CLOF-mediated effects on BA metabolism observed in males, which could be attributed to PPARα-mediated suppression in females on genes involved in BA synthesis and transport. Copyright © 2017 Elsevier Inc. All rights reserved.

Orexin Neurons Are Necessary for the Circadian Control of REM Sleep

PubMed Central

Kantor, Sandor; Mochizuki, Takatoshi; Janisiewicz, Agnieszka M.; Clark, Erika; Nishino, Seiji; Scammell, Thomas E.

2009-01-01

Study Objectives: The orexin-producing neurons are hypothesized to be essential for the circadian control of sleep/wake behavior, but it remains unknown whether these rhythms are mediated by the orexin peptides or by other signaling molecules released by these neurons such as glutamate or dynorphin. To determine the roles of these neurotransmitters, we examined the circadian rhythms of sleep/wake behavior in mice lacking the orexin neurons (ataxin-3 [Atx] mice) and mice lacking just the orexin neuropeptides (orexin knockout [KO] mice). Design: We instrumented mice for recordings of sleep-wake behavior, locomotor activity (LMA), and body temperature (Tb) and recorded behavior after 6 days in constant darkness. Results: The amplitude of the rapid eye movement (REM) sleep rhythm was substantially reduced in Atx mice but preserved in orexin KO mice. This blunted rhythm in Atx mice was caused by an increase in the amount of REM sleep during the subjective night (active period) due to more transitions into REM sleep and longer REM sleep episodes. In contrast, the circadian variations of Tb, LMA, Wake, non-REM sleep, and cataplexy were normal, suggesting that the circadian timekeeping system and other output pathways are intact in both Atx and KO mice. Conclusions: These results indicate that the orexin neurons are necessary for the circadian suppression of REM sleep. Blunting of the REM sleep rhythm in Atx mice but not in orexin KO mice suggests that other signaling molecules such as dynorphin or glutamate may act in concert with orexins to suppress REM sleep during the active period. Citation: Kantor S; Mochizuki T; Janisiewicz AM; Clark E; Nishino S; Scammell TE. Orexin neurons are necessary for the circadian control of REM sleep. SLEEP 2009;32(9):1127-1134. PMID:19750917

PERCEPTION OF SWEET TASTE IS IMPORTANT FOR VOLUNTARY ALCOHOL CONSUMPTION IN MICE

PubMed Central

Blednov, Y.A.; Walker, D.; Martinez, M.; Levine, M.; Damak, S.; Margolskee, R.F.

2012-01-01

To directly evaluate the association between taste perception and alcohol intake, we used three different mutant mice, each lacking a gene expressed in taste buds and critical to taste transduction: α-gustducin (Gnat3), Tas1r3 or Trpm5. Null mutant mice lacking any of these three genes showed lower preference score for alcohol and consumed less alcohol in a two-bottle choice test, as compared with wild-type littermates. These null mice also showed lower preference score for saccharin solutions than did wild-type littermates. In contrast, avoidance of quinine solutions was less in Gnat3 or Trpm5 knockout mice than in wild type mice, whereas Tas1r3 null mice were not different from wild-type in their response to quinine solutions. There were no differences in null vs. wild-type mice in their consumption of sodium chloride solutions. To determine the cause for reduction of ethanol intake, we studied other ethanol-induced behaviors known to be related to alcohol consumption. There were no differences between null and wild-type mice in ethanol-induced loss of righting reflex, severity of acute ethanol withdrawal or conditioned place preference for ethanol. Weaker conditioned taste aversion to alcohol in null mice may have been caused by weaker rewarding value of the conditioned stimulus (saccharin). When saccharin was replaced by sodium chloride, no differences in conditioned taste aversion to alcohol between knockout and wild-type mice were seen. Thus, deletion of any one of three different genes involved in detection of sweet taste leads to a substantial reduction of alcohol intake without any changes in pharmacological actions of ethanol. PMID:17376151

Full-Scale Instrumented Testing and Analysis of Matting Systems for Airfield Parking Ramps and Taxiways

DTIC Science & Technology

2007-12-01

system can only be precisely determined by examining all the materials used in the mat, their structure , orientation, dimensions, etc. and determining...ER D C/ G SL T R- 07 -3 3 Full-Scale Instrumented Testing and Analysis of Matting Systems for Airfield Parking Ramps and Taxiways Chad...ERDC/GSL TR-07-33 December 2007 Full-Scale Instrumented Testing and Analysis of Matting Systems for Airfield Parking Ramps and Taxiways Chad A

Distinct DC subsets regulate adaptive Th1 and 2 responses during Trichuris muris infection.

PubMed

Demiri, M; Müller-Luda, K; Agace, W W; Svensson-Frej, M

2017-10-01

Low- and high-dose infections with the murine large intestinal nematode Trichuris muris are associated with induction of adaptive Th1 and Th2 responses, respectively, in mesenteric lymph nodes (MLN). Classical dendritic cells (cDC) accumulate in the large intestinal mucosa and MLN upon T. muris infection, yet their role in driving adaptive responses to infection remains largely unknown. We performed low- and high-dose T. muris infections of mice deficient in defined cDC subsets to investigate their role in induction of adaptive immune responses. Mice lacking IRF4-dependent cDC failed to clear a high-dose infection and displayed impaired Th2 responses. Conversely, mice lacking IRF8-dependent cDC cleared a low-dose infection and displayed an impaired Th1 response while increased production of Th2 cytokines. Finally, mice lacking both IRF4- and IRF8-dependent cDC were able to generate a Th2 response and clear a low-dose infection. Collectively, these results suggest that IRF4- and IRF8-dependent cDC act antagonistically during T. muris infection, and demonstrate that intestinal Th2 responses can be generated towards T. muris in the absence of IRF4-dependent cDC. © 2017 John Wiley & Sons Ltd.

Proteinase 3 and neutrophil elastase enhance inflammation in mice by inactivating antiinflammatory progranulin

PubMed Central

Kessenbrock, Kai; Fröhlich, Leopold; Sixt, Michael; Lämmermann, Tim; Pfister, Heiko; Bateman, Andrew; Belaaouaj, Azzaq; Ring, Johannes; Ollert, Markus; Fässler, Reinhard; Jenne, Dieter E.

2008-01-01

Neutrophil granulocytes form the body’s first line of antibacterial defense, but they also contribute to tissue injury and noninfectious, chronic inflammation. Proteinase 3 (PR3) and neutrophil elastase (NE) are 2 abundant neutrophil serine proteases implicated in antimicrobial defense with overlapping and potentially redundant substrate specificity. Here, we unraveled a cooperative role for PR3 and NE in neutrophil activation and noninfectious inflammation in vivo, which we believe to be novel. Mice lacking both PR3 and NE demonstrated strongly diminished immune complex–mediated (IC-mediated) neutrophil infiltration in vivo as well as reduced activation of isolated neutrophils by ICs in vitro. In contrast, in mice lacking just NE, neutrophil recruitment to ICs was only marginally impaired. The defects in mice lacking both PR3 and NE were directly linked to the accumulation of antiinflammatory progranulin (PGRN). Both PR3 and NE cleaved PGRN in vitro and during neutrophil activation and inflammation in vivo. Local administration of recombinant PGRN potently inhibited neutrophilic inflammation in vivo, demonstrating that PGRN represents a crucial inflammation-suppressing mediator. We conclude that PR3 and NE enhance neutrophil-dependent inflammation by eliminating the local antiinflammatory activity of PGRN. Our results support the use of serine protease inhibitors as antiinflammatory agents. PMID:18568075

Lack of ecto-5'-nucleotidase (CD73) promotes arteriogenesis.

PubMed

Böring, Yang Chul; Flögel, Ulrich; Jacoby, Christoph; Heil, Matthias; Schaper, Wolfgang; Schrader, Jürgen

2013-01-01

Adenosine can stimulate angiogenesis, but its role in the distinct process of arteriogenesis is unknown. We have previously reported that mice lacking ecto-5'-nucleotidase (CD73-/-) show enhanced monocyte adhesion to the endothelium after ischaemia, which is considered to be an important trigger for arteriogenesis. Hindlimb ischaemia was induced in wild-type (WT) and CD73-/- mice to study the role of extracellularly formed adenosine in arteriogenesis. Magnetic resonance angiography (MRA) was performed for serial visualization of newly developed vessels at a spatial resolution of 1 nL, and high-energy phosphates (HEP) were quantified by (31)P MR spectroscopy (MRS). MRA of CD73-/- mice revealed substantially enhanced collateral artery conductance at day 7 [CD73-/-: 0.73 ± 0.11 a.u. (arbitrary units); WT: 0.44 ± 0.13 a.u.; P < 0.01, n = 6], and MRS of the affected hindlimb showed a faster restoration of HEP in correlation with enhanced functional recovery in the mutant. Additionally, histology showed no differences in capillary density between the groups but showed an increased monocyte infiltration in hindlimbs of CD73-/- mice. Serial assessment of dynamic changes of vessel growth and metabolism in the process of arteriogenesis demonstrate that the lack of CD73-derived adenosine importantly promotes arteriogenesis but does not alter angiogenesis in our model of hindlimb ischaemia.

Fabrication, Polarization of Electrospun Polyvinylidene Fluoride Electret Fibers and Effect on Capturing Nanoscale Solid Aerosols †

PubMed Central

Lolla, Dinesh; Lolla, Manideep; Abutaleb, Ahmed; Shin, Hyeon U.; Reneker, Darrell H.; Chase, George G.

2016-01-01

Electrospun polyvinylidene fluoride (PVDF) fiber mats with average fiber diameters (≈200 nm, ≈2000 nm) were fabricated by controlled electrospinning conditions. These fiber mats were polarized using a custom-made device to enhance the formation of the electret β-phase ferroelectric property of the fibers by simultaneous uniaxial stretching of the fiber mat and heating the mat to the Curie temperature of the PVDF polymer in a strong electric field of 2.5 kV/cm. Scanning electron microscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, differential scanning calorimetry and Brunauer-Emmett-Teller (BET) surface area analyses were performed to characterize both the internal and external morphologies of the fiber mat samples to study polarization-associated changes. MATLAB simulations revealed the changes in the paths of the electric fields and the magnetic flux inside the polarization field with inclusion of the ferroelectric fiber mats. Both polarized and unpolarized fiber mats were challenged as filters against NaCl particles with average particle diameters of about 150 nm using a TSI 8130 to study capture efficiencies and relative pressure drops. Twelve filter experiments were conducted on each sample at one month time intervals between experiments to evaluate the reduction of the polarization enhancement over time. The results showed negligible polarization loss for the 200-nm fiber sample. The polarized mats had the highest filter efficiencies and lowest pressure drops. PMID:28773798

Development of a Twin-spool Turbofan Engine Simulation Using the Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS)

NASA Technical Reports Server (NTRS)

Zinnecker, Alicia M.; Chapman, Jeffryes W.; Lavelle, Thomas M.; Litt, Johathan S.

2014-01-01

The Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS) is a tool that has been developed to allow a user to build custom models of systems governed by thermodynamic principles using a template to model each basic process. Validation of this tool in an engine model application was performed through reconstruction of the Commercial Modular Aero-Propulsion System Simulation (C-MAPSS) (v2) using the building blocks from the T-MATS (v1) library. In order to match the two engine models, it was necessary to address differences in several assumptions made in the two modeling approaches. After these modifications were made, validation of the engine model continued by integrating both a steady-state and dynamic iterative solver with the engine plant and comparing results from steady-state and transient simulation of the T-MATS and C-MAPSS models. The results show that the T-MATS engine model was accurate within 3 of the C-MAPSS model, with inaccuracy attributed to the increased dimension of the iterative solver solution space required by the engine model constructed using the T-MATS library. This demonstrates that, given an understanding of the modeling assumptions made in T-MATS and a baseline model, the T-MATS tool provides a viable option for constructing a computational model of a twin-spool turbofan engine that may be used in simulation studies.

Increasing Mechanical Properties of 2-D-Structured Electrospun Nylon 6 Non-Woven Fiber Mats.

PubMed

Xiang, Chunhui; Frey, Margaret W

2016-04-07

Tensile strength, Young's modulus, and toughness of electrospun nylon 6 non-woven fiber mats were improved by increasing individual nanofiber strength and fiber-fiber load sharing. Single-walled carbon nanotubes (CNTs) were used as reinforcement to increase the strength of the electrospun nylon 6 nanofibers. Young's modulus, tensile strength, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % solutions increased 51%, 87%, and 136%, respectively, after incorporating 1 wt % CNTs into the nylon 6 nanofibers. Three methods were investigated to enhance fiber-fiber load sharing: increasing friction between fibers, thermal bonding, and solvent bonding. The addition of beaded nylon 6 nanofibers into the non-woven fiber mats to increase fiber-fiber friction resulted in a statistically significantly increase in Young's modulus over comparable smooth non-woven fiber mats. After annealing, tensile strength, elongation, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % + 10 wt % solutions increased 26%, 28%, and 68% compared to those from 20 wt % solutions. Solvent bonding with formic acid vapor at room temperature for 30 min caused increases of 56%, 67%, and 39% in the Young's modulus, tensile strength, and toughness of non-woven fiber mats, respectively. The increases attributed to increased individual nanofiber strength and solvent bonding synergistically resulted in the improvement of Young's modulus of the electrospun nylon 6 non-woven fiber mats.

Magnetoacoustic Tomography with Magnetic Induction (MAT-MI) for Breast Tumor Imaging: Numerical Modeling and Simulation

PubMed Central

Zhou, Lian; Li, Xu; Zhu, Shanan; He, Bin

2011-01-01

Magnetoacoustic tomography with magnetic induction (MAT-MI) was recently introduced as a noninvasive electrical conductivity imaging approach with high spatial resolution close to ultrasound imaging. In the present study, we test the feasibility of the MAT-MI method for breast tumor imaging using numerical modeling and computer simulation. Using the finite element method, we have built three dimensional numerical breast models with varieties of embedded tumors for this simulation study. In order to obtain an accurate and stable forward solution that does not have numerical errors caused by singular MAT-MI acoustic sources at conductivity boundaries, we first derive an integral forward method for calculating MAT-MI acoustic sources over the entire imaging volume. An inverse algorithm for reconstructing the MAT-MI acoustic source is also derived with spherical measurement aperture, which simulates a practical setup for breast imaging. With the numerical breast models, we have conducted computer simulations under different imaging parameter setups and all the results suggest that breast tumors that have large conductivity contrast to its surrounding tissues as reported in literature may be readily detected in the reconstructed MAT-MI images. In addition, our simulations also suggest that the sensitivity of imaging breast tumors using the presented MAT-MI setup depends more on the tumor location and the conductivity contrast between the tumor and its surrounding tissues than on the tumor size. PMID:21364262

Relationship between Monokaryotic Growth Rate and Mating Type in the Edible Basidiomycete Pleurotus ostreatus

PubMed Central

Larraya, Luis M.; Pérez, Gúmer; Iribarren, Iñaki; Blanco, Juan A.; Alfonso, Mikel; Pisabarro, Antonio G.; Ramírez, Lucía

2001-01-01

The edible fungus Pleurotus ostreatus (oyster mushroom) is an industrially produced heterothallic homobasidiomycete whose mating is controlled by a bifactorial tetrapolar genetic system. Two mating loci (matA and matB) control different steps of hyphal fusion, nuclear migration, and nuclear sorting during the onset and progress of the dikaryotic growth. Previous studies have shown that the segregation of the alleles present at the matB locus differs from that expected for a single locus because (i) new nonparental B alleles appeared in the progeny and (ii) there was a distortion in the segregation of the genomic regions close to this mating locus. In this study, we pursued these observations by using a genetic approach based on the identification of molecular markers linked to the matB locus that allowed us to dissect it into two genetically linked subunits (matBα and matBβ) and to correlate the presence of specific matBα and matA alleles with differences in monokaryotic growth rate. The availability of these molecular markers and the mating type dependence of growth rate in monokaryons can be helpful for marker-assisted selection of fast-growing monokaryons to be used in the construction of dikaryons able to colonize the substrate faster than the competitors responsible for reductions in the industrial yield of this fungus. PMID:11472908

Effect of the secondary process on mass point vibration velocity propagation in magneto-acoustic tomography and magneto-acousto-electrical tomography.

PubMed

Sun, Zhishen; Liu, Guoqiang; Guo, Liang; Xia, Hui; Wang, Xinli

2016-04-29

As two of the new biological electrical impedance tomography (EIT), magneto-acoustic tomography (MAT) and magneto-acousto-electrical tomography (MAET) achieve both the high contrast property of EIT and the high spatial resolution property of sonography through combining EIT and sonography. As both MAT and MAET contain a uniform magnetic field, vibration and electrical current density, there is a secondary process both in MAT and in MAET, which is MAET and MAT respectively. To analyze the effect of the secondary process on mass point vibration velocity (MPVV) propagation in MAT and MAET. By analyzing the total force to the sample, the wave equations of MPVV in MAT and MAET - when the secondary processes were considered - were derived. The expression of the attenuation constant in the wave number was derived in the case that the mass point vibration velocity propagates in the form of cylindrical wave and plane wave. Attenuations of propagation of the MPVV in several samples were quantified. Attenuations of the MPVV after propagating for 1 mm in copper or aluminum foil, and for 5 cm in gel phantom or biological soft tissue were less than 1%. Attenuations of the MPVV in MAT and MAET due to the secondary processes are relatively minor, and effects of the secondary processes on MPVV propagation in MAT and MAET can be ignored.

Complex polar lipids of a hot spring cyanobacterial mat and its cultivated inhabitants

NASA Technical Reports Server (NTRS)

Ward, D. M.; Panke, S.; Kloppel, K. D.; Christ, R.; Fredrickson, H.

1994-01-01

The complex polar lipids of the hot spring cyanobacterial mat in the 50 to 55 degrees C region of Octopus Spring, Yellowstone National Park, and of thermophilic bacteria cultivated from this or similar habitats, were compared in an attempt to understand the microbial sources of the major lipid biomarkers in this community. Intact complex lipids were analyzed directly by fast atom bombardment mass spectrometry (FAB-MS), two-dimensional thin-layer chromatography (TLC), and combined TLC-FAB-MS. FAB-MS and TLC gave qualitatively similar results, suggesting that the mat contains major lipids most like those of the cyanobacterial isolate we studied, Synechococcus sp. strain Y-7c-s. These include monoglycosyl, diglycosyl, and sulfoquinosovyl diglycerides (MG, DG, and SQ, respectively) and phosphatidyl glycerol (PG). Though Chloroflexus aurantiacus also contains MG, DG, and PG, the fatty acid chain lengths of mat MGs, DGs, and PGs resemble more those of cyanobacterial than green nonsulfur bacterial lipids. FAB-MS spectra of the lipids of nonphototrophic bacterial isolates were distinctively different from those of the mat and phototrophic isolates. The lipids of these nonphototrophic isolates were not detected in the mat, but most could be detected when added to mat samples. The mat also contains major glycolipids and aminophospholipids of unknown structure and origin. FAB-MS and TLC did not always give quantitatively similar results. In particular, PG and SQ may give disproportionately high FAB-MS responses.

Antibacterial electrospun chitosan-polyethylene oxide nanocomposite mats containing ZIF-8 nanoparticles.

PubMed

Kohsari, Iraj; Shariatinia, Zahra; Pourmortazavi, Seied Mahdi

2016-10-01

Antimicrobial chitosan-polyethylene oxide (CS-PEO) nanofiber mats loaded with 3, 5 and 10% (w/w) of zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs, ∼60nm diameter) were developed by electrospinning technique. The CS-PEO-GA-3% ZIF-8 NPs crosslinked with glutaraldehyde (GA) vapor was also prepared. The electrospun mats were characterized by various analysis including FE-SEM, EDAX, elemental mapping, FT-IR, contact angle, TGA/DSC as well as tensile strength analysis. The nanofibers had average diameters within the range ∼70-120nm. Antimicrobial activities of the CS-PEO and CS-PEO-3% ZIF-8 mats were evaluated by the viable cell-counting method for determining their effectiveness in reducing or halting the growth of Staphylococcus aureus and Escherichia coli bacteria so that the CS-PEO mat containing 3% ZIF-8 revealed 100% bactericidal activity against both kinds of bacteria. The crosslinked CS-PEO-GA-3% ZIF-8 NPs sample was less thermally stable but more hydrophilic than its related non-crosslinked mat reflecting there was no need to crosslink the fibers using a chemical crosslinker having adverse effects. The highest hydrophobicity and appropriate thermal and tensile properties of CS-PEO-3% ZIF-8 NPs among those of the mats including 5 and 10% ZIF-8 NPs suggested that the mentioned mat is the most suitable sample for food coating applications. Copyright © 2016 Elsevier B.V. All rights reserved.

The Reverse Transcriptase/RNA Maturase Protein MatR Is Required for the Splicing of Various Group II Introns in Brassicaceae Mitochondria

PubMed Central

Sultan, Laure D.; Grewe, Felix; Rolle, Katarzyna; Abudraham, Sivan; Shevtsov, Sofia; Klipcan, Liron; Barciszewski, Jan; Dietrich, André

2016-01-01

Group II introns are large catalytic RNAs that are ancestrally related to nuclear spliceosomal introns. Sequences corresponding to group II RNAs are found in many prokaryotes and are particularly prevalent within plants organellar genomes. Proteins encoded within the introns themselves (maturases) facilitate the splicing of their own host pre-RNAs. Mitochondrial introns in plants have diverged considerably in sequence and have lost their maturases. In angiosperms, only a single maturase has been retained in the mitochondrial DNA: the matR gene found within NADH dehydrogenase 1 (nad1) intron 4. Its conservation across land plants and RNA editing events, which restore conserved amino acids, indicates that matR encodes a functional protein. However, the biological role of MatR remains unclear. Here, we performed an in vivo investigation of the roles of MatR in Brassicaceae. Directed knockdown of matR expression via synthetically designed ribozymes altered the processing of various introns, including nad1 i4. Pull-down experiments further indicated that MatR is associated with nad1 i4 and several other intron-containing pre-mRNAs. MatR may thus represent an intermediate link in the gradual evolutionary transition from the intron-specific maturases in bacteria into their versatile spliceosomal descendants in the nucleus. The similarity between maturases and the core spliceosomal Prp8 protein further supports this intriguing theory. PMID:27760804

The RY/Sph element mediates transcriptional repression of maturation genes from late maturation to early seedling growth.

PubMed

Guerriero, Gea; Martin, Nathalie; Golovko, Anna; Sundström, Jens F; Rask, Lars; Ezcurra, Ines

2009-11-01

In orthodox seeds, the transcriptional activator ABI3 regulates two major stages in embryo maturation: a mid-maturation (MAT) stage leading to accumulation of storage compounds, and a late maturation (LEA) stage leading to quiescence and desiccation tolerance. Our aim was to elucidate mechanisms for transcriptional shutdown of MAT genes during late maturation, to better understand phase transition between MAT and LEA stages. Using transgenic and transient approaches in Nicotiana, we examined activities of two ABI3-dependent reporter genes driven by multimeric RY and abscisic acid response elements (ABREs) from a Brassica napus napin gene, termed RY and ABRE, where the RY reporter requires ABI3 DNA binding. Expression of RY peaks during mid-maturation and drops during late maturation, mimicking the MAT gene program, and in Arabidopsis thaliana RY elements are over-represented in MAT, but not in LEA, genes. The ABI3 transactivation of RY is inhibited by staurosporine, by a PP2C phosphatase, and by a repressor of maturation genes, VAL1/HSI2. The RY element mediates repression of MAT genes, and we propose that transcriptional shutdown of the MAT program during late maturation involves inhibition of ABI3 DNA binding by dephosphorylation. Later, during seedling growth, VAL1/HSI2 family repressors silence MAT genes by binding RY elements.

DMT1 EXPRESSION IS INCREASED IN THE LUNG OF HYPOTRANSFERRINEMIC MICE

EPA Science Inventory

Despite a lack of transferrin, hypotransferrinemic (Hp) mice demonstrate an accumulation of iron in peripheral organs including the lungs. One potential candidate for such transferrin-independent uptake of iron is divalent metal transporter-1 (DMT1), an established iron transport...

Sedimentology, Mineralogy, Morphology, and Characterization of Purple Non-Sulfur Bacteria Communities from Modern Hypersaline Microbial Mats in Puerto Rico and the Virgin Islands

NASA Astrophysics Data System (ADS)

Rodriguez Colon, B. J.; Rivera-Lopez, E. O.; Ramirez-Martinez, W. R.; Rios-Velazquez, C.; Perez-Valentin, K. A.

2017-12-01

Microbial mats are organosedimentary structures which house complex guilds of microbial communities, held together by a gelatinous exopolymeric substance (EPS). This biofilm contributes to the formation of laminations by binding and trapping sediments, as well as in-situ organomineralization. Microbial mats commonly thrive in extreme habitats, such as the hypersaline environments, which have been studied throughout several coastal regions in the Caribbean. This project aims to study the morphology, sedimentology, and mineralogy of five different modern hypersaline microbial mats from Puerto Rico and Anegada that have not yet been studied, to assess their differences/similarities. At the same time, we intent to isolate and characterize purple non-sulfur bacteria (PNSB), which is an anoxyphototrophic microorganism that contributes to the pink pigmentation observed in the second layer of a typical microbial mat. Different layers within each mat were separated, dissected and dissolved to remove all organic material. The resulting sediment was then analyzed mineralogically using X-ray diffraction, and used to make petrographic thin sections. To isolate PNSB candidates, serial dilutions followed by filtration were performed to extracted sections from the pink layer of each mat. The samples were planted in Petri dishes with marine media and placed in Anaerobic Jars. Colonies Descriptions, Gram stain and molecular analysis using 16S rDNA gene was performed. Preliminary results show a diversity of mat morphologies throughout the ponds, similar to what has been observed in other hypersaline ponds and marshes in the Caribbean. Sedimentary analysis shows that the mats from Puerto Rico have similar allochthonous material (e.g. Halimeda sp. fragments). Microcodium fabrics, conoform structures, and hemispheroidal morphologies were observed as well. In Anegada, lithified microbialites were observed in the Red Pond location. Mineralogically, all samples were similar except for the mats in Cabo Rojo, Puerto Rico, which contained allochthonous quartz. 38 possible PNSB candidates were isolated from the mats, showing similar colonial characteristics (convex elevations, entire margins and pink pigmentations). Molecular results will be shown during the meeting.

Spatial Structure and Activity of Sedimentary Microbial Communities Underlying a Beggiatoa spp. Mat in a Gulf of Mexico Hydrocarbon Seep

PubMed Central

Lloyd, Karen G.; Albert, Daniel B.; Biddle, Jennifer F.; Chanton, Jeffrey P.; Pizarro, Oscar; Teske, Andreas

2010-01-01

Background Subsurface fluids from deep-sea hydrocarbon seeps undergo methane- and sulfur-cycling microbial transformations near the sediment surface. Hydrocarbon seep habitats are naturally patchy, with a mosaic of active seep sediments and non-seep sediments. Microbial community shifts and changing activity patterns on small spatial scales from seep to non-seep sediment remain to be examined in a comprehensive habitat study. Methodology/Principal Findings We conducted a transect of biogeochemical measurements and gene expression related to methane- and sulfur-cycling at different sediment depths across a broad Beggiatoa spp. mat at Mississippi Canyon 118 (MC118) in the Gulf of Mexico. High process rates within the mat (∼400 cm and ∼10 cm from the mat's edge) contrasted with sharply diminished activity at ∼50 cm outside the mat, as shown by sulfate and methane concentration profiles, radiotracer rates of sulfate reduction and methane oxidation, and stable carbon isotopes. Likewise, 16S ribosomal rRNA, dsrAB (dissimilatory sulfite reductase) and mcrA (methyl coenzyme M reductase) mRNA transcripts of sulfate-reducing bacteria (Desulfobacteraceae and Desulfobulbaceae) and methane-cycling archaea (ANME-1 and ANME-2) were prevalent at the sediment surface under the mat and at its edge. Outside the mat at the surface, 16S rRNA sequences indicated mostly aerobes commonly found in seawater. The seep-related communities persisted at 12–20 cm depth inside and outside the mat. 16S rRNA transcripts and V6-tags reveal that bacterial and archaeal diversity underneath the mat are similar to each other, in contrast to oxic or microoxic habitats that have higher bacterial diversity. Conclusions/Significance The visual patchiness of microbial mats reflects sharp discontinuities in microbial community structure and activity over sub-meter spatial scales; these discontinuities have to be taken into account in geochemical and microbiological inventories of seep environments. In contrast, 12–20 cm deep in the sediments microbial communities performing methane-cycling and sulfate reduction persist at lower metabolic rates regardless of mat cover, and may increase activity rapidly when subsurface flow changes. PMID:20090951

Low-Light Anoxygenic Photosynthesis and Fe-S-Biogeochemistry in a Microbial Mat

PubMed Central

Haas, Sebastian; de Beer, Dirk; Klatt, Judith M.; Fink, Artur; Rench, Rebecca McCauley; Hamilton, Trinity L.; Meyer, Volker; Kakuk, Brian; Macalady, Jennifer L.

2018-01-01

We report extremely low-light-adapted anoxygenic photosynthesis in a thick microbial mat in Magical Blue Hole, Abaco Island, The Bahamas. Sulfur cycling was reduced by iron oxides and organic carbon limitation. The mat grows below the halocline/oxycline at 30 m depth on the walls of the flooded sinkhole. In situ irradiance at the mat surface on a sunny December day was between 0.021 and 0.084 μmol photons m-2 s-1, and UV light (<400 nm) was the most abundant part of the spectrum followed by green wavelengths (475–530 nm). We measured a light-dependent carbon uptake rate of 14.5 nmol C cm-2 d-1. A 16S rRNA clone library of the green surface mat layer was dominated (74%) by a cluster (>97% sequence identity) of clones affiliated with Prosthecochloris, a genus within the green sulfur bacteria (GSB), which are obligate anoxygenic phototrophs. Typical photopigments of brown-colored GSB, bacteriochlorophyll e and (β-)isorenieratene, were abundant in mat samples and their absorption properties are well-adapted to harvest light in the available green and possibly even UV-A spectra. Sulfide from the water column (3–6 μmol L-1) was the main source of sulfide to the mat as sulfate reduction rates in the mats were very low (undetectable-99.2 nmol cm-3 d-1). The anoxic water column was oligotrophic and low in dissolved organic carbon (175–228 μmol L-1). High concentrations of pyrite (FeS2; 1–47 μmol cm-3) together with low microbial process rates (sulfate reduction, CO2 fixation) indicate that the mats function as net sulfide sinks mainly by abiotic processes. We suggest that abundant Fe(III) (4.3–22.2 μmol cm-3) is the major source of oxidizing power in the mat, and that abiotic Fe-S-reactions play the main role in pyrite formation. Limitation of sulfate reduction by low organic carbon availability along with the presence of abundant sulfide-scavenging iron oxides considerably slowed down sulfur cycling in these mats. PMID:29755448

Low-Light Anoxygenic Photosynthesis and Fe-S-Biogeochemistry in a Microbial Mat.

PubMed

Haas, Sebastian; de Beer, Dirk; Klatt, Judith M; Fink, Artur; Rench, Rebecca McCauley; Hamilton, Trinity L; Meyer, Volker; Kakuk, Brian; Macalady, Jennifer L

2018-01-01

We report extremely low-light-adapted anoxygenic photosynthesis in a thick microbial mat in Magical Blue Hole, Abaco Island, The Bahamas. Sulfur cycling was reduced by iron oxides and organic carbon limitation. The mat grows below the halocline/oxycline at 30 m depth on the walls of the flooded sinkhole. In situ irradiance at the mat surface on a sunny December day was between 0.021 and 0.084 μmol photons m -2 s -1 , and UV light (<400 nm) was the most abundant part of the spectrum followed by green wavelengths (475-530 nm). We measured a light-dependent carbon uptake rate of 14.5 nmol C cm -2 d -1 . A 16S rRNA clone library of the green surface mat layer was dominated (74%) by a cluster (>97% sequence identity) of clones affiliated with Prosthecochloris , a genus within the green sulfur bacteria (GSB), which are obligate anoxygenic phototrophs. Typical photopigments of brown-colored GSB, bacteriochlorophyll e and (β-)isorenieratene, were abundant in mat samples and their absorption properties are well-adapted to harvest light in the available green and possibly even UV-A spectra. Sulfide from the water column (3-6 μmol L -1 ) was the main source of sulfide to the mat as sulfate reduction rates in the mats were very low (undetectable-99.2 nmol cm -3 d -1 ). The anoxic water column was oligotrophic and low in dissolved organic carbon (175-228 μmol L -1 ). High concentrations of pyrite (FeS 2 ; 1-47 μmol cm -3 ) together with low microbial process rates (sulfate reduction, CO 2 fixation) indicate that the mats function as net sulfide sinks mainly by abiotic processes. We suggest that abundant Fe(III) (4.3-22.2 μmol cm -3 ) is the major source of oxidizing power in the mat, and that abiotic Fe-S-reactions play the main role in pyrite formation. Limitation of sulfate reduction by low organic carbon availability along with the presence of abundant sulfide-scavenging iron oxides considerably slowed down sulfur cycling in these mats.

Nonwoven glass fiber mat reinforces polyurethane adhesive

NASA Technical Reports Server (NTRS)

Roseland, L. M.

1967-01-01

Nonwoven glass fiber mat reinforces the adhesive properties of a polyurethane adhesive that fastens hardware to exterior surfaces of aluminum tanks. The mat is embedded in the uncured adhesive. It ensures good control of the bond line and increases the peel strength.

Vertical Geochemical Profiling Across a 3.33 Ga Microbial Mat from Barberton

NASA Astrophysics Data System (ADS)

Westall, F.; Lemelle, L.; Simionovici, A.; Southam, G.; Maclean, L.; Salomé, M.; Wirick, S.; Toporski, J.; Jauss, A.

2008-03-01

The Josefdal Chert (3.33 Ga), Barberton, contains a superbly preserved microbial mat. High resolution geochemical profiling across the mat documents textures and compositions indicative of a mixed microbial community of anoxygenic photosynthesisers and probably SRBs.

Galectin-1-Driven Tolerogenic Programs Aggravate Yersinia enterocolitica Infection by Repressing Antibacterial Immunity.

PubMed

Davicino, Roberto C; Méndez-Huergo, Santiago P; Eliçabe, Ricardo J; Stupirski, Juan C; Autenrieth, Ingo; Di Genaro, María S; Rabinovich, Gabriel A

2017-08-15

Yersinia enterocolitica is an enteropathogenic bacterium that causes gastrointestinal disorders, as well as extraintestinal manifestations. To subvert the host's immune response, Y. enterocolitica uses a type III secretion system consisting of an injectisome and effector proteins, called Yersinia outer proteins (Yops), that modulate activation, signaling, and survival of immune cells. In this article, we show that galectin-1 (Gal-1), an immunoregulatory lectin widely expressed in mucosal tissues, contributes to Y. enterocolitica pathogenicity by undermining protective antibacterial responses. We found higher expression of Gal-1 in the spleen and Peyer's patches of mice infected orogastrically with Y. enterocolitica serotype O:8 compared with noninfected hosts. This effect was prevented when mice were infected with Y. enterocolitica lacking YopP or YopH, two critical effectors involved in bacterial immune evasion. Consistent with a regulatory role for this lectin during Y. enterocolitica pathogenesis, mice lacking Gal-1 showed increased weight and survival, lower bacterial load, and attenuated intestinal pathology compared with wild-type mice. These protective effects involved modulation of NF-κB activation, TNF production, and NO synthesis in mucosal tissue and macrophages, as well as systemic dysregulation of IL-17 and IFN-γ responses. In vivo neutralization of these proinflammatory cytokines impaired bacterial clearance and eliminated host protection conferred by Gal-1 deficiency. Finally, supplementation of recombinant Gal-1 in mice lacking Gal-1 or treatment of wild-type mice with a neutralizing anti-Gal-1 mAb confirmed the immune inhibitory role of this endogenous lectin during Y. enterocolitica infection. Thus, targeting Gal-1-glycan interactions may contribute to reinforce antibacterial responses by reprogramming innate and adaptive immune mechanisms. Copyright © 2017 by The American Association of Immunologists, Inc.

Mice lacking the conserved transcription factor Grainyhead-like 3 (Grhl3) display increased apposition of the frontal and parietal bones during embryonic development.

PubMed

Goldie, Stephen J; Arhatari, Benedicta D; Anderson, Peter; Auden, Alana; Partridge, Darren D; Jane, Stephen M; Dworkin, Sebastian

2016-10-18

Increased apposition of the frontal and parietal bones of the skull during embryogenesis may be a risk factor for the subsequent development of premature skull fusion, or craniosynostosis. Human craniosynostosis is a prevalent, and often serious embryological and neonatal pathology. Other than known mutations in a small number of contributing genes, the aetiology of craniosynostosis is largely unknown. Therefore, the identification of novel genes which contribute to normal skull patterning, morphology and premature suture apposition is imperative, in order to fully understand the genetic regulation of cranial development. Using advanced imaging techniques and quantitative measurement, we show that genetic deletion of the highly-conserved transcription factor Grainyhead-like 3 (Grhl3) in mice (Grhl3 -/- ) leads to decreased skull size, aberrant skull morphology and premature apposition of the coronal sutures during embryogenesis. Furthermore, Grhl3 -/- mice also present with premature collagen deposition and osteoblast alignment at the sutures, and the physical interaction between the developing skull, and outermost covering of the brain (the dura mater), as well as the overlying dermis and subcutaneous tissue, appears compromised in embryos lacking Grhl3. Although Grhl3 -/- mice die at birth, we investigated skull morphology and size in adult animals lacking one Grhl3 allele (heterozygous; Grhl3 +/- ), which are viable and fertile. We found that these adult mice also present with a smaller cranial cavity, suggestive of post-natal haploinsufficiency in the context of cranial development. Our findings show that our Grhl3 mice present with increased apposition of the frontal and parietal bones, suggesting that Grhl3 may be involved in the developmental pathogenesis of craniosynostosis.

Deletion of Lkb1 in Pro-Opiomelanocortin Neurons Impairs Peripheral Glucose Homeostasis in Mice

PubMed Central

Claret, Marc; Smith, Mark A.; Knauf, Claude; Al-Qassab, Hind; Woods, Angela; Heslegrave, Amanda; Piipari, Kaisa; Emmanuel, Julian J.; Colom, André; Valet, Philippe; Cani, Patrice D.; Begum, Ghazala; White, Anne; Mucket, Phillip; Peters, Marco; Mizuno, Keiko; Batterham, Rachel L.; Giese, K. Peter; Ashworth, Alan; Burcelin, Remy; Ashford, Michael L.; Carling, David; Withers, Dominic J.

2011-01-01

OBJECTIVE AMP-activated protein kinase (AMPK) signaling acts as a sensor of nutrients and hormones in the hypothalamus, thereby regulating whole-body energy homeostasis. Deletion of Ampkα2 in pro-opiomelanocortin (POMC) neurons causes obesity and defective neuronal glucose sensing. LKB1, the Peutz-Jeghers syndrome gene product, and Ca2+-calmodulin–dependent protein kinase kinase β (CaMKKβ) are key upstream activators of AMPK. This study aimed to determine their role in POMC neurons upon energy and glucose homeostasis regulation. RESEARCH DESIGN AND METHODS Mice lacking either Camkkβ or Lkb1 in POMC neurons were generated, and physiological, electrophysiological, and molecular biology studies were performed. RESULTS Deletion of Camkkβ in POMC neurons does not alter energy homeostasis or glucose metabolism. In contrast, female mice lacking Lkb1 in POMC neurons (PomcLkb1KO) display glucose intolerance, insulin resistance, impaired suppression of hepatic glucose production, and altered expression of hepatic metabolic genes. The underlying cellular defect in PomcLkb1KO mice involves a reduction in melanocortin tone caused by decreased α-melanocyte–stimulating hormone secretion. However, Lkb1-deficient POMC neurons showed normal glucose sensing, and body weight was unchanged in PomcLkb1KO mice. CONCLUSIONS Our findings demonstrate that LKB1 in hypothalamic POMC neurons plays a key role in the central regulation of peripheral glucose metabolism but not body-weight control. This phenotype contrasts with that seen in mice lacking AMPK in POMC neurons with defects in body-weight regulation but not glucose homeostasis, which suggests that LKB1 plays additional functions distinct from activating AMPK in POMC neurons. PMID:21266325

Effect of concrete slats, three mat types and out-wintering pads on performance and welfare of finishing beef steers.

PubMed

Earley, Bernadette; McNamara, John D; Jerrams, Stephen J; O'Riordan, Edward G

2017-05-30

The objective was to investigate the effect of placing mats on concrete slatted floors on performance, behaviour, hoof condition, dirt scores, physiological and immunological variables of beef steers, and to compare responses with animals on out-wintering pads. Continental crossbred beef steers [n = 360; mean (±SD) initial live weight 539 kg (42.2)] were blocked by breed and live weight and randomly assigned to one of five treatments; (1) Concrete slats alone, (2) Mat 1 (Natural Rubber structure) (Durapak Rubber Products), (3) Mat 2 (Natural rubber structure) (EasyFix), (4) Mat 3 (modified ethylene vinyl acetate (EVA) foam structure) and (5) Out-wintering pads (OWP's). Animals on the OWPs had a greater (P < 0.05) live weight gain (P < 0.05) compared with the slat and Mat 2 treatments: results for Mat 1 and Mat 3 were the same (P > 0.05) as the other treatments. Animals on the OWPs had reduced lying percentage time compared with all the other treatments. Dry matter (DM) intake was greater for animals on the OWPs compared with all the other treatments. Carcass weight, kill out proportion, carcass fat score, carcass composition score, FCR and physiological responses were similar (P > 0.05) among treatments. No incidence of laminitis was observed among treatments. The number of hoof lesions was greater on all mat types (P < 0.05) compared with concrete slats and OWP treatments. Dirt scores were greater (P < 0.05) for animals on OWPs when measured on days 42, 84, 105, 126 and 150 compared with animals on slats. Under the conditions adopted for the present study, there was no evidence to suggest that animals housed on bare concrete slats were disadvantaged in respect of animal welfare compared with animals housed on other floor types. It is concluded that the welfare of steers was not adversely affected by slats compared with different mat types or OWPs.

Groundwater shapes sediment biogeochemistry and microbial diversity in a submerged Great Lake sinkhole.

PubMed

Kinsman-Costello, L E; Sheik, C S; Sheldon, N D; Allen Burton, G; Costello, D M; Marcus, D; Uyl, P A Den; Dick, G J

2017-03-01

For a large part of earth's history, cyanobacterial mats thrived in low-oxygen conditions, yet our understanding of their ecological functioning is limited. Extant cyanobacterial mats provide windows into the putative functioning of ancient ecosystems, and they continue to mediate biogeochemical transformations and nutrient transport across the sediment-water interface in modern ecosystems. The structure and function of benthic mats are shaped by biogeochemical processes in underlying sediments. A modern cyanobacterial mat system in a submerged sinkhole of Lake Huron (LH) provides a unique opportunity to explore such sediment-mat interactions. In the Middle Island Sinkhole (MIS), seeping groundwater establishes a low-oxygen, sulfidic environment in which a microbial mat dominated by Phormidium and Planktothrix that is capable of both anoxygenic and oxygenic photosynthesis, as well as chemosynthesis, thrives. We explored the coupled microbial community composition and biogeochemical functioning of organic-rich, sulfidic sediments underlying the surface mat. Microbial communities were diverse and vertically stratified to 12 cm sediment depth. In contrast to previous studies, which used low-throughput or shotgun metagenomic approaches, our high-throughput 16S rRNA gene sequencing approach revealed extensive diversity. This diversity was present within microbial groups, including putative sulfate-reducing taxa of Deltaproteobacteria, some of which exhibited differential abundance patterns in the mats and with depth in the underlying sediments. The biological and geochemical conditions in the MIS were distinctly different from those in typical LH sediments of comparable depth. We found evidence for active cycling of sulfur, methane, and nutrients leading to high concentrations of sulfide, ammonium, and phosphorus in sediments underlying cyanobacterial mats. Indicators of nutrient availability were significantly related to MIS microbial community composition, while LH communities were also shaped by indicators of subsurface groundwater influence. These results show that interactions between the mats and sediments are crucial for sustaining this hot spot of biological diversity and biogeochemical cycling. © 2016 John Wiley & Sons Ltd.

Species richness and community composition of mat-forming ectomycorrhizal fungi in old- and second-growth Douglas-fir forests of the HJ Andrews Experimental Forest, Oregon, USA.

PubMed

Dunham, Susie M; Larsson, Karl-Henrik; Spatafora, Joseph W

2007-11-01

We investigated the species identity of mat-forming ectomycorrhizal (EM) fungi associated with old- and second-growth Douglas-fir stands. Using molecular analyses of rhizomorphs and EM root tips, we characterized 28 unique internal transcribed spacer sequences and considered them proxies for mat-forming EM species. In both stand age classes, one Athelioid species in the genus Piloderma dominated our sample of the mat-forming fungal community. In second-growth stands, the second most frequently encountered mat-forming EM species belonged to the genus Hysterangium. In old-growth stands, several Ramaria species were associated with a frequently encountered mat morphology but no species dominated the community. After using rarefaction analysis to standardize sampling effort, the total species richness did not differ statistically between old- and second-growth habitats. Both an abundance of infrequently encountered species and incomplete sampling of the mat-forming EM community may have limited our ability to detect potential differences in species richness. Several frequently encountered Piloderma species appear to have broad (holarctic) distributions and diverse host associations and their potential importance in forest ecosystems warrants further study.

Ecological succession leads to chemosynthesis in mats colonizing wood in sea water.

PubMed

Kalenitchenko, Dimitri; Dupraz, Marlène; Le Bris, Nadine; Petetin, Carole; Rose, Christophe; West, Nyree J; Galand, Pierre E

2016-09-01

Chemosynthetic mats involved in cycling sulfur compounds are often found in hydrothermal vents, cold seeps and whale falls. However, there are only few records of wood fall mats, even though the presence of hydrogen sulfide at the wood surface should create a perfect niche for sulfide-oxidizing bacteria. Here we report the growth of microbial mats on wood incubated under conditions that simulate the Mediterranean deep-sea temperature and darkness. We used amplicon and metagenomic sequencing combined with fluorescence in situ hybridization to test whether a microbial succession occurs during mat formation and whether the wood fall mats present chemosynthetic features. We show that the wood surface was first colonized by sulfide-oxidizing bacteria belonging to the Arcobacter genus after only 30 days of immersion. Subsequently, the number of sulfate reducers increased and the dominant Arcobacter phylotype changed. The ecological succession was reflected by a change in the metabolic potential of the community from chemolithoheterotrophs to potential chemolithoautotrophs. Our work provides clear evidence for the chemosynthetic nature of wood fall ecosystems and demonstrates the utility to develop experimental incubation in the laboratory to study deep-sea chemosynthetic mats.

Heroin refusal self-efficacy and preference for medication-assisted treatment after inpatient detoxification.

PubMed

Kenney, Shannon R; Bailey, Genie L; Anderson, Bradley J; Stein, Michael D

2017-10-01

An individual's self-efficacy to refuse using heroin in high-risk situations is believed to minimize the likelihood for relapse. However, among individuals completing inpatient heroin detoxification, perceived refusal self-efficacy may also reduce one's perceived need for medication-assisted treatment (MAT), an effective and recommended treatment for opioid use disorder. In the current study, we examined the relationship between heroin refusal self-efficacy and preference for MAT following inpatient detoxification. Participants (N=397) were interviewed at the start of brief inpatient opioid detoxification. Multiple logistic regression was used to estimate the adjusted association of background characteristics, depressed mood, and perceived heroin refusal self-efficacy with preference for MAT. Controlling for other covariates, depressed mood and lower perceived refusal self-efficacy were associated with a significantly greater likelihood of expressing preference for MAT (versus no MAT). Perceived ability to refuse heroin after leaving detox is inversely associated with a heroin user's desire for MAT. An effective continuum of care model may benefit from greater attention to patient's perceived refusal self-efficacy during detoxification which may impact preference for MAT and long-term recovery. Copyright © 2017. Published by Elsevier Ltd.

Expansion rate and geometry of floating vegetation mats on the margins of thermokarst lakes, northern Seward Peninsula, Alaska, USA

USGS Publications Warehouse

Parsekian, A.D.; Jones, Benjamin M.; Jones, M.; Grosse, G.; Walter, Anthony K.M.; Slater, L.

2011-01-01

Investigations on the northern Seward Peninsula in Alaska identified zones of recent (<50years) permafrost collapse that led to the formation of floating vegetation mats along thermokarst lake margins. The occurrence of floating vegetation mat features indicates rapid degradation of near-surface permafrost and lake expansion. This paper reports on the recent expansion of these collapse features and their geometry is determined using geophysical and remote sensing measurements. The vegetation mats were observed to have an average thickness of 0.57m and petrophysical modeling indicated that gas content of 1.5-5% enabled floatation above the lake surface. Furthermore, geophysical investigation provides evidence that the mats form by thaw and subsidence of the underlying permafrost rather than terrestrialization. The temperature of the water below a vegetation mat was observed to remain above freezing late in the winter. Analysis of satellite and aerial imagery indicates that these features have expanded at maximum rates of 1-2myr-1 over a 56year period. Including the spatial coverage of floating 'thermokarst mats' increases estimates of lake area by as much as 4% in some lakes. ?? 2011 John Wiley & Sons, Ltd.

Testlet-Based Multidimensional Adaptive Testing

PubMed Central

Frey, Andreas; Seitz, Nicki-Nils; Brandt, Steffen

2016-01-01

Multidimensional adaptive testing (MAT) is a highly efficient method for the simultaneous measurement of several latent traits. Currently, no psychometrically sound approach is available for the use of MAT in testlet-based tests. Testlets are sets of items sharing a common stimulus such as a graph or a text. They are frequently used in large operational testing programs like TOEFL, PISA, PIRLS, or NAEP. To make MAT accessible for such testing programs, we present a novel combination of MAT with a multidimensional generalization of the random effects testlet model (MAT-MTIRT). MAT-MTIRT compared to non-adaptive testing is examined for several combinations of testlet effect variances (0.0, 0.5, 1.0, and 1.5) and testlet sizes (3, 6, and 9 items) with a simulation study considering three ability dimensions with simple loading structure. MAT-MTIRT outperformed non-adaptive testing regarding the measurement precision of the ability estimates. Further, the measurement precision decreased when testlet effect variances and testlet sizes increased. The suggested combination of the MTIRT model therefore provides a solution to the substantial problems of testlet-based tests while keeping the length of the test within an acceptable range. PMID:27917132

Full-Scale Evaluation of DuraDeck (registered trademark) and MegaDeck (trademark) Matting Systems

DTIC Science & Technology

2013-07-01

plates studded with threaded bolts were placed ERDC/GSL TR-13-27 10 underneath two pre-drilled corners of the panel. The plates were positioned so...metal plates studded with threaded ERDC/GSL TR-13-27 4 Figure 1. DuraDeck® mat panel, top surface. Figure 2. DuraDeck® mat panel, bottom surface...ERDC/GSL TR-13-27 5 bolts , as shown in Figure 3, underneath the mat corners and then installing special connector nuts from the top surface

Magnetoacoustic tomographic imaging of electrical impedance with magnetic induction

PubMed Central

Xia, Rongmin; Li, Xu; He, Bin

2008-01-01

Magnetoacoustic tomography with magnetic induction (MAT-MI) is a recently introduced method for imaging tissue electrical impedance properties by integrating magnetic induction and ultrasound measurements. In the present study, we have developed a focused cylindrical scanning mode MAT-MI system and the corresponding reconstruction algorithms. Using this system, we demonstrated 3-dimensional MAT-MI imaging in a physical phantom, with cylindrical scanning combined with ultrasound focusing, and the ability of MAT-MI in imaging electrical conductivity properties of biological tissue. PMID:19169372

Magnetoacoustic tomographic imaging of electrical impedance with magnetic induction

NASA Astrophysics Data System (ADS)

Xia, Rongmin; Li, Xu; He, Bin

2007-08-01

Magnetoacoustic tomography with magnetic induction (MAT-MI) is a recently introduced method for imaging tissue electrical impedance properties by integrating magnetic induction and ultrasound measurements. In the present study, the authors have developed a focused cylindrical scanning mode MAT-MI system and the corresponding reconstruction algorithms. Using this system, they demonstrated a three-dimensional MAT-MI imaging approach in a physical phantom, with cylindrical scanning combined with ultrasound focusing, and the ability of MAT-MI in imaging electrical conductivity properties of biological tissue.

Magnetoacoustic tomographic imaging of electrical impedance with magnetic induction.

PubMed

Xia, Rongmin; Li, Xu; He, Bin

2007-08-22

Magnetoacoustic tomography with magnetic induction (MAT-MI) is a recently introduced method for imaging tissue electrical impedance properties by integrating magnetic induction and ultrasound measurements. In the present study, we have developed a focused cylindrical scanning mode MAT-MI system and the corresponding reconstruction algorithms. Using this system, we demonstrated 3-dimensional MAT-MI imaging in a physical phantom, with cylindrical scanning combined with ultrasound focusing, and the ability of MAT-MI in imaging electrical conductivity properties of biological tissue.

Dietary fructose-induced hepatocellular carcinoma development manifested in mice lacking apoptosis inhibitor of macrophage (AIM).

PubMed

Ozawa, Takayuki; Maehara, Natsumi; Kai, Toshihiro; Arai, Satoko; Miyazaki, Toru

2016-12-01

The consumption of fructose, including the use of high-fructose corn syrup as a sweetener, has increased continuously in recent decades. Although the involvement of fructose in the development of metabolic diseases has been emphasized recently, whether fructose intake increases susceptibility to steatosis-associated hepatocellular carcinoma (HCC) is unclear. Here, we investigated this issue using mice lacking a circulating protein, apoptosis inhibitor of macrophage (AIM, encoded by cd5l). AIM does not induce carcinogenesis of hepatocytes, but provokes necrotic death specifically in AIM-bound cancer cells through complement cascade activation, thereby preventing HCC tumor development in wild-type mice. When subjected to a high-fructose diet (HFrD), AIM-deficient (AIM -/- ) mice showed liver steatosis and subsequent liver inflammation as well as fibrosis, but at much milder levels compared with mice fed a high-fat diet. However, AIM -/- mice were markedly susceptible to HCC tumor development, whereas no wild-type mice developed the disease. Systemic metabolic states, including obesity and insulin resistance, were similar in both types of mice after HFrD challenge, indicating no influence of AIM on HFrD-induced metabolic changes. Our results suggest that dietary fructose increases the risk for liver carcinogenesis and that individuals with low blood AIM levels may be susceptible to HCC under chronic fructose intake. © 2016 The Authors. Genes to Cells published by Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

BEHAVIORAL AND NEUROCHEMICAL CHARACTERIZATION OF THE mlh MUTANT MICE LACKING OTOCONIA.

PubMed

Manes, Marianna; Garcia-Gomes, Mariana de Souza Aranha; Sandini, Thaísa Meira; Zaccarelli-Magalhães, J; Florio, J C; Alexandre-Ribeiro, Sandra Regina; Wadt, Danilo; Bernardi, Maria Martha; Massironi, Silvia Maria Gomes; Mori, Claudia Madalena Cabrera

2018-06-15

Otoconia are crucial for the correct processing of positional information and orientation. Mice lacking otoconia cannot sense the direction of the gravity vector and cannot swim properly. This study aims to characterize the behavior of mergulhador (mlh), otoconia-deficient mutant mice. Additionally, the central catecholamine levels were evaluated to investigate possible correlations between behaviors and central neurotransmitters. A sequence of behavioral tests was used to evaluate the parameters related to the general activity, sensory nervous system, psychomotor system, and autonomous nervous system, in addition to measuring the acquisition of spatial and declarative memory, anxiety-like behavior, motor coordination, and swimming behavior of the mlh mutant mice. As well, the neurotransmitter levels in the cerebellum, striatum, frontal cortex, and hippocampus were measured. Relative to BALB/c mice, the mutant mlh mice showed 1) reduced locomotor and rearing behavior, increased auricular and touch reflexes, decreased motor coordination and increased micturition; 2) decreased responses in the T-maze and aversive wooden beam tests; 3) increased time of immobility in the tail suspension test; 4) no effects in the elevated plus maze or object recognition test; 5) an inability to swim; and 6) reduced turnover of dopaminergic system in the cerebellum, striatum, and frontal cortex. Thus, in our mlh mutant mice, otoconia deficiency reduced the motor, sensory and spatial learning behaviors likely by impairing balance. We did not rule out the role of the dopaminergic system in all behavioral deficits of the mlh mutant mice. Copyright © 2018. Published by Elsevier B.V.

Hepatic Gluconeogenesis Is Enhanced by Phosphatidic Acid Which Remains Uninhibited by Insulin in Lipodystrophic Agpat2−/− Mice*

PubMed Central

Sankella, Shireesha; Garg, Abhimanyu; Horton, Jay D.; Agarwal, Anil K.

2014-01-01

In this study we examined the role of phosphatidic acid (PA) in hepatic glucose production (HGP) and development of hepatic insulin resistance in mice that lack 1-acylglycerol-3-phosphate O-acyltransferase 2 (AGPAT2). Liver lysophosphatidic acid and PA levels were increased ∼2- and ∼5-fold, respectively, in male Agpat2−/− mice compared with wild type mice. In the absence of AGPAT2, the liver can synthesize PAs by activating diacylglycerol kinase or phospholipase D, both of which were elevated in the livers of Agpat2−/− mice. We found that PAs C16:0/18:1 and C18:1/20:4 enhanced HGP in primary WT hepatocytes, an effect that was further enhanced in primary hepatocytes from Agpat2−/− mice. Lysophosphatidic acids C16:0 and C18:1 failed to increase HGP in primary hepatocytes. The activation of HGP was accompanied by an up-regulation of the key gluconeogenic enzymes glucose-6-phosphatase and phosphoenolpyruvate carboxykinase. This activation was suppressed by insulin in the WT primary hepatocytes but not in the Agpat2−/− primary hepatocytes. Thus, the lack of normal insulin signaling in Agpat2−/− livers allows unrestricted PA-induced gluconeogenesis significantly contributing to the development of hyperglycemia in these mice. PMID:24425876

Desacyl Ghrelin Decreases Anxiety-like Behavior in Male Mice.

PubMed

Mahbod, Parinaz; Smith, Eric P; Fitzgerald, Maureen E; Morano, Rachel L; Packard, Benjamin A; Ghosal, Sriparna; Scheimann, Jessie R; Perez-Tilve, Diego; Herman, James P; Tong, Jenny

2018-01-01

Ghrelin is a 28-amino acid polypeptide that regulates feeding, glucose metabolism, and emotionality (stress, anxiety, and depression). Plasma ghrelin circulates as desacyl ghrelin (DAG) or, in an acylated form, acyl ghrelin (AG), through the actions of ghrelin O-acyltransferase (GOAT), exhibiting low or high affinity, respectively, for the growth hormone secretagogue receptor (GHSR) 1a. We investigated the role of endogenous AG, DAG, and GHSR1a signaling on anxiety and stress responses using ghrelin knockout (Ghr KO), GOAT KO, and Ghsr stop-floxed (Ghsr null) mice. Behavioral and hormonal responses were tested in the elevated plus maze and light/dark (LD) box. Mice lacking both AG and DAG (Ghr KO) increased anxiety-like behaviors across tests, whereas anxiety reactions were attenuated in DAG-treated Ghr KO mice and in mice lacking AG (GOAT KO). Notably, loss of GHSR1a (Ghsr null) did not affect anxiety-like behavior in any test. Administration of AG and DAG to Ghr KO mice with lifelong ghrelin deficiency reduced anxiety-like behavior and decreased phospho-extracellular signal-regulated kinase phosphorylation in the Edinger-Westphal nucleus in wild-type mice, a site normally expressing GHSR1a and involved in stress- and anxiety-related behavior. Collectively, our data demonstrate distinct roles for endogenous AG and DAG in regulation of anxiety responses and suggest that the behavioral impact of ghrelin may be context dependent. Copyright © 2018 Endocrine Society.

Renal tubular ACE-mediated tubular injury is the major contributor to microalbuminuria in early diabetic nephropathy.

PubMed

Eriguchi, Masahiro; Lin, Mercury; Yamashita, Michifumi; Zhao, Tuantuan V; Khan, Zakir; Bernstein, Ellen A; Gurley, Susan B; Gonzalez-Villalobos, Romer A; Bernstein, Kenneth E; Giani, Jorge F

2018-04-01

Diabetic nephropathy is a major cause of end-stage renal disease in developed countries. While angiotensin-converting enzyme (ACE) inhibitors are used to treat diabetic nephropathy, how intrarenal ACE contributes to diabetic renal injury is uncertain. Here, two mouse models with different patterns of renal ACE expression were studied to determine the specific contribution of tubular vs. glomerular ACE to early diabetic nephropathy: it-ACE mice, which make endothelial ACE but lack ACE expression by renal tubular epithelium, and ACE 3/9 mice, which lack endothelial ACE and only express renal ACE in tubular epithelial cells. The absence of endothelial ACE normalized the glomerular filtration rate and endothelial injury in diabetic ACE 3/9 mice. However, these mice developed tubular injury and albuminuria and displayed low renal levels of megalin that were similar to those observed in diabetic wild-type mice. In diabetic it-ACE mice, despite hyperfiltration, the absence of renal tubular ACE greatly reduced tubulointerstitial injury and albuminuria and increased renal megalin expression compared with diabetic wild-type and diabetic ACE 3/9 mice. These findings demonstrate that endothelial ACE is a central regulator of the glomerular filtration rate while tubular ACE is a key player in the development of tubular injury and albuminuria. These data suggest that tubular injury, rather than hyperfiltration, is the main cause of microalbuminuria in early diabetic nephropathy.

Alopecia of IFN-gamma knockout mouse as a model for disturbance of the hair cycle: a unique arrest of the hair cycle at the anagen phase accompanied by mitosis.

PubMed

Hirota, Ryuichiro; Tajima, Sadao; Yoneda, Yukio; Tamayama, Takumi; Watanabe, Masahito; Ueda, Kouichi; Kubota, Takahiro; Yoshida, Ryotaro

2002-09-01

Interferon-gamma(-/-) (IFN-gamma(-/-)) and IFN-gamma(+/+) C57BL/6 mice (3 weeks of age) completed the production of morphogenesis-derived hair. Around 6 weeks of age, however, most of the IFN-gamma(-/-) but none of the IFN-gamma(+/+) mice began to lose hairs in the dorsal and occipital areas in the absence of inflammatory reactions, and the alopecia was sustained for at least several 10-week periods of observation. A single subcutaneous injection of IFN-gamma to IFN-gamma(-/-) mice at 3, but not 4, 5, or 8 weeks of age could protect all the mice from alopecia, revealing that the lack of IFN-gamma around 3 weeks of age is directly responsible for the alopecia. Histologic features showed that the hair follicles of the IFN-gamma(+/+) mice passed through the anagen (4-5 weeks of age) and catagen/telogen ( approximately 6 weeks of age) phases, whereas those of IFN-gamma(-/-) mice (5 weeks of age or older) stayed in the anagen phase. TUNEL and bromodeoxyuridine experiments suggested that an arrest with unlimited DNA synthesis of the hair cycle in the anagen phase by the lack of IFN-gamma-dependent apoptosis in the midfollicle region and diffuse shedding of previously formed hair induced alopecia in IFN-gamma(-/-) mice.

Remodeling of the Cervix and Parturition in Mice Lacking the Progesterone Receptor B Isoform1

PubMed Central

Yellon, Steven M.; Oshiro, Bryan T.; Chhaya, Tejas Y.; Lechuga, Thomas J.; Dias, Rejane M.; Burns, Alexandra E.; Force, Lindsey; Apostolakis, Ede M.

2011-01-01

Withdrawal of progestational support for pregnancy is part of the final common pathways for parturition, but the role of nuclear progesterone receptor (PGR) isoforms in this process is not known. To determine if the PGR-B isoform participates in cervical remodeling at term, cervices were obtained from mice lacking PGR-B (PGR-BKO) and from wild-type (WT) controls before or after birth. PGR-BKO mice gave birth to viable pups at the same time as WT controls during the early morning of Day 19 postbreeding. Morphological analyses indicated that by the day before birth, cervices from PGR-BKO and WT mice had increased in size, with fewer cell nuclei/area as well as diminished collagen content and structure, as evidenced by optical density of picrosirius red-stained sections, compared to cervices from nonpregnant mice. Moreover, increased numbers of resident macrophages, but not neutrophils, were found in the prepartum cervix of PGR-BKO compared to nonpregnant mice, parallel to findings in WT mice. These results suggest that PGR-B does not contribute to the growth or degradation of the extracellular matrix or proinflammatory processes associated with recruitment of macrophages in the cervix leading up to birth. Rather, other receptors may contribute to the progesterone-dependent mechanism that promotes remodeling of the cervix during pregnancy and in the proinflammatory process associated with ripening before parturition. PMID:21613631

Distribution of Major Chlorogenic Acids and Related Compounds in Brazilian Green and Toasted Ilex paraguariensis (Maté) Leaves.

PubMed

Lima, Juliana de Paula; Farah, Adriana; King, Benjamin; de Paulis, Tomas; Martin, Peter R

2016-03-23

Ilex paraguariensis (maté) is one of the best sources of chlorogenic acids (CGA) in nature. When leaves are toasted, some isomers are partly transformed into 1,5-γ-quinolactones (CGL). Both CGA and CGL are important contributors to the brew's flavor and are thought to contribute to human health. In this study, we quantified 9 CGA, 2 CGL, and caffeic acid in 20 samples of dried green and toasted maté that are commercially available in Brazil. Total CGA content in green maté varied from 8.7 to 13.2 g/100 g, dry weight (dw). Caffeic acid content varied from 10.8 to 13.5 mg/100 g dw, respectively. Content in toasted maté varied from 1.5 to 4.6 g/100 g and from 1.5 to 7.2 mg/100 g dw, respectively. Overall, caffeoylquinic acid isomers (CQA) were the most abundant CGA in both green and toasted maté, followed by dicaffeoylquinic acids (diCQA) and feruloylquinic acids (FQA). These classes accounted for 58.5%, 40.0%, and 1.5% of CGA, respectively, in green maté and 76.3%, 20.7%, and 3.0%, respectively, in toasted maté. Average contents of 3-caffeoylquinolactone (3-CQL) and 4-caffeoylquinolactone (4-CQL) in commercial toasted samples were 101.5 mg/100 g and 61.8 mg/100 g dw, respectively. These results show that, despite overall losses during the toasting process, CGA concentrations are still substantial in toasted leaves, compared to other food sources of CGA and phenolic compounds in general. In addition to evaluating commercial samples, investigation of changes in CGA profile and formation of 1,5-γ-quinolactones was performed in experimental maté toasting.

Fermentation couples Chloroflexi and sulfate-reducing bacteria to Cyanobacteria in hypersaline microbial mats

PubMed Central

Lee, Jackson Z.; Burow, Luke C.; Woebken, Dagmar; Everroad, R. Craig; Kubo, Mike D.; Spormann, Alfred M.; Weber, Peter K.; Pett-Ridge, Jennifer; Bebout, Brad M.; Hoehler, Tori M.

2013-01-01

Past studies of hydrogen cycling in hypersaline microbial mats have shown an active nighttime cycle, with production largely from Cyanobacteria and consumption from sulfate-reducing bacteria (SRB). However, the mechanisms and magnitude of hydrogen cycling have not been extensively studied. Two mats types near Guerrero Negro, Mexico—permanently submerged Microcoleus microbial mat (GN-S), and intertidal Lyngbya microbial mat (GN-I)—were used in microcosm diel manipulation experiments with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), molybdate, ammonium addition, and physical disruption to understand the processes responsible for hydrogen cycling between mat microbes. Across microcosms, H2 production occurred under dark anoxic conditions with simultaneous production of a suite of organic acids. H2 production was not significantly affected by inhibition of nitrogen fixation, but rather appears to result from constitutive fermentation of photosynthetic storage products by oxygenic phototrophs. Comparison to accumulated glycogen and to CO2 flux indicated that, in the GN-I mat, fermentation released almost all of the carbon fixed via photosynthesis during the preceding day, primarily as organic acids. Across mats, although oxygenic and anoxygenic phototrophs were detected, cyanobacterial [NiFe]-hydrogenase transcripts predominated. Molybdate inhibition experiments indicated that SRBs from a wide distribution of DsrA phylotypes were responsible for H2 consumption. Incubation with 13C-acetate and NanoSIMS (secondary ion mass-spectrometry) indicated higher uptake in both Chloroflexi and SRBs relative to other filamentous bacteria. These manipulations and diel incubations confirm that Cyanobacteria were the main fermenters in Guerrero Negro mats and that the net flux of nighttime fermentation byproducts (not only hydrogen) was largely regulated by the interplay between Cyanobacteria, SRBs, and Chloroflexi. PMID:24616716

Engineering and Scientific Applications: Using MatLab(Registered Trademark) for Data Processing and Visualization

NASA Technical Reports Server (NTRS)

Sen, Syamal K.; Shaykhian, Gholam Ali

2011-01-01

MatLab(TradeMark)(MATrix LABoratory) is a numerical computation and simulation tool that is used by thousands Scientists and Engineers in many countries. MatLab does purely numerical calculations, which can be used as a glorified calculator or interpreter programming language; its real strength is in matrix manipulations. Computer algebra functionalities are achieved within the MatLab environment using "symbolic" toolbox. This feature is similar to computer algebra programs, provided by Maple or Mathematica to calculate with mathematical equations using symbolic operations. MatLab in its interpreter programming language form (command interface) is similar with well known programming languages such as C/C++, support data structures and cell arrays to define classes in object oriented programming. As such, MatLab is equipped with most of the essential constructs of a higher programming language. MatLab is packaged with an editor and debugging functionality useful to perform analysis of large MatLab programs and find errors. We believe there are many ways to approach real-world problems; prescribed methods to ensure foregoing solutions are incorporated in design and analysis of data processing and visualization can benefit engineers and scientist in gaining wider insight in actual implementation of their perspective experiments. This presentation will focus on data processing and visualizations aspects of engineering and scientific applications. Specifically, it will discuss methods and techniques to perform intermediate-level data processing covering engineering and scientific problems. MatLab programming techniques including reading various data files formats to produce customized publication-quality graphics, importing engineering and/or scientific data, organizing data in tabular format, exporting data to be used by other software programs such as Microsoft Excel, data presentation and visualization will be discussed.

MAT, a Novel Polyherbal Aphrodisiac Formulation, Enhances Sexual Function and Nrf2/HO-1 Pathway While Reducing Oxidative Damage in Male Rats

PubMed Central

Tuzcu, Mehmet; Orhan, Cemal; Sahin, Nurhan; Akdemir, Fatih; Yilmaz, Ismet

2018-01-01

Mucuna pruriens, Ashwagandha, and Tribulus terrestris are known as the enhancers for sexual health, functional activities, vitality, and longevity. These herbs had been widely used in the Ayurveda medicine as aphrodisiacs through the ages, and their efficacy was also verified separately in our previous publication. Therefore, the aim of this study was to determine the effects of Mucuna, Ashwagandha, and Tribulus complexes on sexual function in rats. Twenty-eight male rats allocated to four groups as follows: (i) negative control (C); (ii) positive control or sildenafil citrate treated group (5 mg/kg) (S); (iii) MAT1 (combination of 10 mg Mucuna (M) + 10 mg Ashwagandha (A) + 10 mg Tribulus (T)/kg BW); (iv) MAT 2 (20 mg Mucuna + 20 mg Ashwagandha + 20 mg Tribulus/kg BW). There was no significant difference found between the MAT1 and MAT2 groups while they showed significantly increased testosterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) levels when compared to the negative control. Significant increases in Nrf2/HO1 levels and decreases in NF-κB were detected in MAT groups similar to the decrease in serum and testis malondialdehyde (MDA) levels as compared to both controls. The sperm motility, count, and rate also significantly improved in both MAT groups, while ALT, AST, creatinine, ALP, and urea levels did not change in any of the groups. Oral consumption of MATs combination in male rats resulted in inhibition of NF-κB and MDA and also increased sex hormones with Nrf2-mediated HO-1 induction. MAT combinations may improve sexual functions by increasing levels of sexual hormones and regulation of NF-κB and Nrf2/HO-1 signaling pathways. PMID:29853975

Fermentation couples Chloroflexi and sulfate-reducing bacteria to Cyanobacteria in hypersaline microbial mats

DOE PAGES

Lee, Jackson Z.; Burow, Luke C.; Woebken, Dagmar; ...

2014-01-01

Past studies of hydrogen cycling in hypersaline microbial mats have shown an active nighttime cycle, with production largely from Cyanobacteria and consumption from sulfate-reducing bacteria (SRB). However, the mechanisms and magnitude of hydrogen cycling have not been extensively studied. Two mats types near Guerrero Negro, Mexico$-$ permanently submerged Microcoleus microbial mat (GN-S), and intertidal Lyngbya microbial mat (GN-I)$-$were used in microcosm diel manipulation experiments with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), molybdate, ammonium addition, and physical disruption to understand the processes responsible for hydrogen cycling between mat microbes. Across microcosms, H 2 production occurred under dark anoxic conditions with simultaneous production of a suitemore » of organic acids. H 2 production was not significantly affected by inhibition of nitrogen fixation, but rather appears to result from constitutive fermentation of photosynthetic storage products by oxygenic phototrophs. Comparison to accumulated glycogen and to CO 2 flux indicated that, in the GN-I mat, fermentation released almost all of the carbon fixed via photosynthesis during the preceding day, primarily as organic acids. Across mats, although oxygenic and anoxygenic phototrophs were detected, cyanobacterial [NiFe]-hydrogenase transcripts predominated. Molybdate inhibition experiments indicated that SRBs from a wide distribution of DsrA phylotypes were responsible for H 2 consumption. Incubation with 13C-acetate and NanoSIMS (secondary ion mass-spectrometry) indicated higher uptake in both Chloroflexi and SRBs relative to other filamentous bacteria. These manipulations and diel incubations confirm that Cyanobacteria were the main fermenters in Guerrero Negro mats and that the net flux of nighttime fermentation byproducts (not only hydrogen) was largely regulated by the interplay between Cyanobacteria, SRBs, and Chloroflexi.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beam, Jake; Bernstein, Hans C.; Jay, Z.

Iron oxide microbial mats are ubiquitous geobiological features on Earth and occur in extant acidic hot springs of Yellowstone National Park (YNP), WY, USA, and form as a result of microbial processes. The relative contribution of different organisms to the development of these mat ecosystems is of specific interest. We hypothesized that chemolithoautotrophic organisms contribute to the early development and production of Fe(III)-oxide mats, which could support later-colonizing heterotrophic microorganisms. Sterile glass slides were incubated in the outflow channels of two acidic geothermal springs in YNP, and spatiotemporal changes in Fe(III)-oxide accretion and abundance of relevant community members were measured.more » Lithoautotrophic Hydrogenobaculum spp. were first colonizers and the most abundant taxa identified during early successional stages (7 – 40 days). Populations of M. yellowstonensis colonized after ~ 7 days, corresponding to visible Fe(III)-oxide accretion. Heterotrophic archaea colonized after 30 days, and emerge as the dominant functional guild in mature iron oxide mats (1 – 2 cm thick) that form after 70 – 120 days. First-order rate constants of iron oxide accretion ranged from 0.05 – 0.046 day-1, and reflected the absolute amount of iron accreted. Micro- and macroscale microterracettes were identified during iron oxide mat development, and suggest that the mass transfer of oxygen limits microbial growth. This was also demonstrated using microelectrode measurements of oxygen as a function of mat depth, which showed steep gradients in oxygen from the aqueous mat interface to ~ 1 mm. The formation and succession of amorphous Fe(III)-oxide mat communities follows a predictable pattern of distinct stages and growth. The successional stages and microbial signatures observed in these extant Fe(III)-oxide mat communities may be relevant to other past or present Fe(III)-oxide mineralizing systems.« less

Environmental controls on photosynthetic microbial mat distribution and morphogenesis on a 3.42 Ga clastic-starved platform.

PubMed

Tice, Michael M

2009-12-01

Three morphotypes of microbial mats are preserved in rocks deposited in shallow-water facies of the 3.42 Ga Buck Reef chert (BRC). Morphotype alpha consists of fine anastomosing and bifurcating carbonaceous laminations, which loosely drape underlying detrital grains or form silica-filled lenses. Morphotype beta consists of meshes of fine carbonaceous strands intergrown with detrital grains and dark laminations, which loosely drape coarse detrital grains. Morphotype gamma consists of fine, even carbonaceous laminations that tightly drape underlying detrital grains. Preservation of nearly uncompacted mat morphologies and detrital grains deposited during mat growth within a well-characterized sedimentary unit makes quantitative correlation between morphology and paleoenvironment possible. All mats are preserved in the shallowest-water interval of those rocks deposited below normal wave base and above storm wave base. This interval is bounded below by a transgressive lag formed during regional flooding and above by a small condensed section that marks a local relative sea-level maximum. Restriction of all mat morphotypes to the shallowest interval of the storm-active layer in the BRC ocean reinforces previous interpretations that these mats were constructed primarily by photosynthetic organisms. Morphotypes alpha and beta dominate the lower half of this interval and grew during deposition of relatively coarse detrital carbonaceous grains, while morphotype gamma dominates the upper half and grew during deposition of fine detrital carbonaceous grains. The observed mat distribution suggests that either light intensity or, more likely, small variations in ambient current energy acted as a first-order control on mat morphotype distribution. These results demonstrate significant environmental control on biological morphogenetic processes independent of influences from siliciclastic sedimentation.

Chitosan-rectorite nanospheres immobilized on polystyrene fibrous mats via alternate electrospinning/electrospraying techniques for copper ions adsorption

NASA Astrophysics Data System (ADS)

Tu, Hu; Huang, Mengtian; Yi, Yang; Li, Zhenshun; Zhan, Yingfei; Chen, Jiajia; Wu, Yang; Shi, Xiaowen; Deng, Hongbing; Du, Yumin

2017-12-01

Chitosan (CS), as a kind of well characterized biopolymer, has been used for heavy metal adsorption due to its low cost and high efficacy. However, when used directly, chitosan particles had small surface area and weak mechanical strength which is unfavorable to metal adsorption and reused. Besides, it cannot be easily recycled that may cause a secondary pollution. In this paper, CS and layered silicate rectorite (REC) were fully mixed and the mixtures were subsequently electrosprayed nano-sized spheres, which were immobilized on the surface of electrospun polystyrene (PS) mats for metal adsorption. The morphology analysis taken from SEM confirmed that CS-REC nanospheres were loaded on the surface of PS fibrous mats. Small Angle X-ray diffraction patterns showed that the interlayer distance of REC in composite mats was enlarged by the intercalation of CS chains; such structure meant bigger surface area which was helpful for metal adsorption. The data of contact angle implied that PS mats coated with CS-REC nanospheres exhibited better hydrophilicity than PS mats, which was conductive to adsorption rate. Besides, the copper ions adsorption of composite mats was tested at different conditions including the adsorption time, the initial pH and the initial concentration of copper ion. The results demonstrated that PS mats coated with CS-REC nanospheres had the adsorption capacity up to 134 mg/g. In addition, the addition of REC containing Ca2+ could also improve the metal adsorption because of cation exchange. The desorption assay indicated that PS mats immobilized with CS and CS-REC still kept high adsorption ability which retained 74% and 78% after three adsorption-desorption cycles.

CaCO3 Precipitation in Multilayered Cyanobacterial Mats: Clues to Explain the Alternation of Micrite and Sparite Layers in Calcareous Stromatolites

PubMed Central

Kaźmierczak, Józef; Fenchel, Tom; Kühl, Michael; Kempe, Stephan; Kremer, Barbara; Łącka, Bożena; Małkowski, Krzysztof

2015-01-01

Marine cyanobacterial mats were cultured on coastal sediments (Nivå Bay, Øresund, Denmark) for over three years in a closed system. Carbonate particles formed in two different modes in the mat: (i) through precipitation of submicrometer-sized grains of Mg calcite within the mucilage near the base of living cyanobacterial layers, and (ii) through precipitation of a variety of mixed Mg calcite/aragonite morphs in layers of degraded cyanobacteria dominated by purple sulfur bacteria. The δ13C values were about 2‰ heavier in carbonates from the living cyanobacterial zones as compared to those generated in the purple bacterial zones. Saturation indices calculated with respect to calcite, aragonite, and dolomite inside the mats showed extremely high values across the mat profile. Such high values were caused by high pH and high carbonate alkalinity generated within the mats in conjunction with increased concentrations of calcium and magnesium that were presumably stored in sheaths and extracellular polymer substances (EPS) of the living cyanobacteria and liberated during their post-mortem degradation. The generated CaCO3 morphs were highly similar to morphs reported from heterotrophic bacterial cultures, and from bacterially decomposed cyanobacterial biomass emplaced in Ca-rich media. They are also similar to CaCO3 morphs precipitated from purely inorganic solutions. No metabolically (enzymatically) controlled formation of particular CaCO3 morphs by heterotrophic bacteria was observed in the studied mats. The apparent alternation of in vivo and post-mortem generated calcareous layers in the studied cyanobacterial mats may explain the alternation of fine-grained (micritic) and coarse-grained (sparitic) laminae observed in modern and fossil calcareous cyanobacterial microbialites as the result of a probably similar multilayered mat organization. PMID:25761263

Absence of fear renewal and functional connections between prefrontal cortex and hippocampus in infant mice.

PubMed

Li, Liyu; Gao, Xiaoli; Zhou, Qiang

2018-04-20

Impairment in fear extinction is widely viewed as a major contributor to, or even an underlying mechanism of, the pathogenesis of anxiety disorders and PTSD. Children with traumatic experience have a higher risk for developing anxiety disorders and PTSD in the adult. Little is known about the nature of fear memory extinction and its underlying mechanism during this period. Here we showed that while renewal of fear memory is context-specific in adult mice, it is absent in infant mice (P17). Using local injection of GABAa receptor antagonist picrotoxin, we found that there is no functional connectivity between infralimbic prefrontal cortex and hippocampus in P17 mice, while prefrontal cortex projection to amygdala is functioning. Hence, the lack of fear renewal is likely caused by the lack of connections between hippocampus and prefrontal cortex which are known to be involved in the regulation of extinction memory. Copyright © 2018 Elsevier Inc. All rights reserved.

The Small GTP-Binding Protein Rhes Influences Nigrostriatal-Dependent Motor Behavior During Aging.

PubMed

Pinna, Annalisa; Napolitano, Francesco; Pelosi, Barbara; Di Maio, Anna; Wardas, Jadwiga; Casu, Maria Antonietta; Costa, Giulia; Migliarini, Sara; Calabresi, Paolo; Pasqualetti, Massimo; Morelli, Micaela; Usiello, Alessandro

2016-04-01

Here we aimed to evaluate: (1) Rhes mRNA expression in mouse midbrain, (2) the effect of Rhes deletion on the number of dopamine neurons, (3) nigrostriatal-sensitive behavior during aging in knockout mice. Radioactive in situ hybridization was assessed in adult mice. The beam-walking test was executed in 3-, 6- and 12-month-old mice. Immunohistochemistry of midbrain tyrosine hydroxylase (TH)-positive neurons was performed in 6- and 12-month-old mice. Rhes mRNA is expressed in TH-positive neurons of SNpc and the ventral tegmental area. Moreover, lack of Rhes leads to roughly a 20% loss of nigral TH-positive neurons in both 6- and 12-month-old mutants, when compared with their age-matched controls. Finally, lack of Rhes triggers subtle alterations in motor performance and coordination during aging. Our findings indicate a fine-tuning role of Rhes in regulating the number of TH-positive neurons of the substantia nigra and nigrostriatal-sensitive motor behavior during aging. © 2016 International Parkinson and Movement Disorder Society.

Mice lacking the extracellular matrix protein MAGP1 display delayed thrombotic occlusion following vessel injury

PubMed Central

Werneck, Claudio C.; Vicente, Cristina P.; Weinberg, Justin S.; Shifren, Adrian; Pierce, Richard A.; Broekelmann, Thomas J.; Tollefsen, Douglas M.

2008-01-01

Mice lacking the extracellular matrix protein microfibril-associated glycoprotein-1 (MAGP1) display delayed thrombotic occlusion of the carotid artery following injury as well as prolonged bleeding from a tail vein incision. Normal occlusion times were restored when recombinant MAGP1 was infused into deficient animals prior to vessel wounding. Blood coagulation was normal in these animals as assessed by activated partial thromboplastin time and prothrombin time. Platelet number was lower in MAGP1-deficient mice, but the platelets showed normal aggregation properties in response to various agonists. MAGP1 was not found in normal platelets or in the plasma of wild-type mice. In ligand blot assays, MAGP1 bound to fibronectin, fibrinogen, and von Willebrand factor, but von Willebrand factor was the only protein of the 3 that bound to MAGP1 in surface plasmon resonance studies. These findings show that MAGP1, a component of microfibrils and vascular elastic fibers, plays a role in hemostasis and thrombosis. PMID:18281502

Fabrication of nanofiber mats from electrospinning of functionalized polymers

NASA Astrophysics Data System (ADS)

Oktay, Burcu; Kayaman-Apohan, Nilhan; Erdem-Kuruca, Serap

2014-08-01

Electrospinning technique enabled us to prepare nanofibers from synthetic and natural polymers. In this study, it was aimed to fabricate electrospun poly(vinyl alcohol) (PVA) based nanofibers by reactive electrospinning process. To improve endurance of fiber toward to many solvents, PVA was functionalized with photo-crosslinkable groups before spinning. Afterward PVA was crosslinked by UV radiation during electrospinning process. The nanofiber mats were characterized by scanning electron microscopy (SEM). The results showed that homogenous, uniform and crosslinked PVA nanofibers in diameters of about 200 nm were obtained. Thermal stability of the nanofiber mat was investigated with thermal gravimetric analysis (TGA). Also the potential use of this nanofiber mats for tissue engineering was examined. Osteosarcoma (Saos) cells were cultured on the nanofiber mats.

Development of an active isolation mat based on dielectric elastomer stack actuators for mechanical vibration cancellation

NASA Astrophysics Data System (ADS)

Karsten, Roman; Flittner, Klaus; Haus, Henry; Schlaak, Helmut F.

2013-04-01

This paper describes the development of an active isolation mat for cancelation of vibrations on sensitive devices with a mass of up to 500 gram. Vertical disturbing vibrations are attenuated actively while horizontal vibrations are damped passively. The dimensions of the investigated mat are 140 × 140 × 20 mm. The mat contains 5 dielectric elastomer stack actuators (DESA). The design and the optimization of active isolation mat are realized by ANSYS FEM software. The best performance shows a DESA with air cushion mounted on its circumference. Within the mounting encased air increases static and reduces dynamic stiffness. Experimental results show that vibrations with amplitudes up to 200 μm can be actively eliminated.

Endosomal/Lysosomal Processing of Gangliosides Affects Neuronal Cholesterol Sequestration in Niemann-Pick Disease Type C

PubMed Central

Zhou, Sharon; Davidson, Cristin; McGlynn, Robert; Stephney, Gloria; Dobrenis, Kostantin; Vanier, Marie T.; Walkley, Steven U.

2011-01-01

Niemann-Pick disease type C (NPC) is a severe neurovisceral lysosomal storage disorder caused by defects in NPC1 or NPC2 proteins. Although numerous studies support the primacy of cholesterol storage, neurons of double-mutant mice lacking both NPC1 and an enzyme required for synthesis of all complex gangliosides (β1,4GalNAc transferase) have been reported to exhibit dramatically reduced cholesterol sequestration. Here we show that NPC2-deficient mice lacking this enzyme also exhibit reduced cholesterol, but that genetically restricting synthesis to only a-series gangliosides fully restores neuronal cholesterol storage to typical disease levels. Examining the subcellular locations of sequestered compounds in neurons lacking NPC1 or NPC2 by confocal microscopy revealed that cholesterol and the two principal storage gangliosides (GM2 and GM3) were not consistently co-localized within the same intracellular vesicles. To determine whether the lack of GM2 and GM3 co-localization was due to differences in synthetic versus degradative pathway expression, we generated mice lacking both NPC1 and lysosomal β-galactosidase, and therefore unable to generate GM2 and GM3 in lysosomes. Double mutants lacked both gangliosides, indicating that each is the product of endosomal/lysosomal processing. Unexpectedly, GM1 accumulation in double mutants increased compared to single mutants consistent with a direct role for NPC1 in ganglioside salvage. These studies provide further evidence that NPC1 and NPC2 proteins participate in endosomal/lysosomal processing of both sphingolipids and cholesterol. PMID:21708114

Deficiency of CB2 cannabinoid receptor in mice improves insulin sensitivity but increases food intake and obesity with age.

PubMed

Agudo, J; Martin, M; Roca, C; Molas, M; Bura, A S; Zimmer, A; Bosch, F; Maldonado, R

2010-12-01

The endocannabinoid system has a key role in energy storage and metabolic disorders. The endocannabinoid receptor 2 (CB2R), which was first detected in immune cells, is present in the main peripheral organs responsible for metabolic control. During obesity, CB2R is involved in the development of adipose tissue inflammation and fatty liver. We examined the long-term effects of CB2R deficiency in glucose metabolism. Mice deficient in CB2R (Cb2 ( -/- ) [also known as Cnr2]) were studied at different ages (2-12 months). Two-month-old Cb2 (-/-) and wild-type mice were treated with a selective CB2R antagonist or fed a high-fat diet. The lack of CB2R in Cb2 (-/-) mice led to greater increases in food intake and body weight with age than in Cb2 (+/+) mice. However, 12-month-old obese Cb2 (-/-) mice did not develop insulin resistance and showed enhanced insulin-stimulated glucose uptake in skeletal muscle. In agreement, adipose tissue hypertrophy was not associated with inflammation. Similarly, treatment of wild-type mice with CB2R antagonist resulted in improved insulin sensitivity. Moreover, when 2-month-old Cb2 (-/-) mice were fed a high-fat diet, reduced body weight gain and normal insulin sensitivity were observed. These results indicate that the lack of CB2R-mediated responses protected mice from both age-related and diet-induced insulin resistance, suggesting that these receptors may be a potential therapeutic target in obesity and insulin resistance.

Learning and Memory Impairments in a Congenic C57BL/6 Strain of Mice That Lacks the M2 Muscarinic Acetylcholine Receptor Subtype

PubMed Central

Bainbridge, Natalie K.; Koselke, Lisa R.; Jeon, Jongrye; Bailey, Kathleen R.; Wess, Jürgen; Crawley, Jacqueline N.; Wrenn, Craige C.

2009-01-01

The neurotransmitter acetylcholine is an important modulator of cognitive functions including attention, learning, and memory. The actions of acetylcholine are mediated by five distinct muscarinic acetylcholine receptor subtypes (M1-M5). The lack of drugs with a high degree of selectivity for these subtypes has impeded the determination of which subtypes mediate which components of cholinergic neurotransmission relevant to cognitive abilities. The present study examined the behavioral functions of the M2 muscarinic receptor subtype by utilizing congenic C57BL/6 mice possessing a null-mutation in the M2 muscarinic receptor gene (M2−/− mice). Comprehensive assessment of general health and neurological function found no major differences between M2−/− and wild-type (M2+/+) mice. In tests of learning and memory, M2−/− mice were impaired in the acquisition (trials to criterion), but not the retention (72 hr) of a passive avoidance task. In a novel open field, M2−/− mice were impaired in between-sessions, but not within-session habituation. In a holeboard test of spatial memory, M2−/− mice committed more errors in working memory than M2+/+ mice. Reference memory did not differ between the genotypes. M2−/− mice showed no impairments in either cued or contextual fear conditioning. These findings replicate and extend earlier findings in a hybrid strain and solidify the interpretation that the M2 receptor plays a critical role in specific components of cognitive abilities. PMID:18346798

Regional changes in the cholinergic system in mice lacking monoamine oxidase A.

PubMed

Grailhe, Régis; Cardona, Ana; Even, Naïla; Seif, Isabelle; Changeux, Jean-Pierre; Cloëz-Tayarani, Isabelle

2009-03-30

Elevated brain monoamine concentrations resulting from monoamine oxidase A genetic ablation (MAOA knock-out mice) lead to changes in other neurotransmitter systems. To investigate the consequences of MAOA deficiency on the cholinergic system, we measured ligand binding to the high-affinity choline transporter (CHT1) and to muscarinic and nicotinic receptors in brain sections of MAOA knock-out (KO) and wild-type mice. A twofold increase in [(3)H]-hemicholinium-3 ([(3)H]-HC-3) binding to CHT1 was observed in the caudate putamen, nucleus accumbens, and motor cortex in MAOA KO mice as compared with wild-type (WT) mice. There was no difference in [(3)H]-HC-3 labeling in the hippocampus (dentate gyrus) between the two genotypes. Binding of [(125)I]-epibatidine ([(125)I]-Epi), [(125)I]-alpha-bungarotoxin ([(125)I]-BGT), [(3)H]-pirenzepine ([(3)H]-PZR), and [(3)H]-AFDX-384 ([(3)H]-AFX), which respectively label high- and low-affinity nicotinic receptors, M1 and M2 muscarinic cholinergic receptors, was not modified in the caudate putamen, nucleus accumbens, and motor cortex. A small but significant decrease of 19% in M1 binding densities was observed in the hippocampus (CA1 field) of KO mice. Next, we tested acetylcholinesterase activity and found that it was decreased by 25% in the striatum of KO mice as compared with WT mice. Our data suggest that genetic deficiency in MAOA enzyme is associated with changes in cholinergic activity, which may account for some of the behavioral alterations observed in mice and humans lacking MAOA.

Distinct tissue site-specific requirements of mast cells and complement components C3/C5a receptor in IgG immune complex-induced injury of skin and lung.

PubMed

Baumann, U; Chouchakova, N; Gewecke, B; Köhl, J; Carroll, M C; Schmidt, R E; Gessner, J E

2001-07-15

We induced the passive reverse Arthus reaction to IgG immune complexes (IC) at different tissue sites in mice lacking C3 treated or not with a C5aR-specific antagonist, or in mice lacking mast cells (Kit(W)/Kit(W-v) mice), and compared the inflammatory responses with those in the corresponding wild-type mice. We confirmed that IC inflammation of skin can be mediated largely by mast cells expressing C5aR and FcgammaRIII. In addition, we provided evidence for C3-independent C5aR triggering, which may explain why the cutaneous Arthus reaction develops normally in C3(-/-) mice. Furthermore, some, but not all, of the acute changes associated with the Arthus response in the lung were significantly more intense in normal mice than in C3(-/-) or Kit(W)/Kit(W-v) mice, indicating for C3- and mast cell-dependent and -independent components. Finally, we demonstrated that C3 contributed to the elicitation of neutrophils to alveoli, which corresponded to an increased synthesis of TNF-alpha, macrophage-inflammatory protein-2, and cytokine-induced neutrophil chemoattractant. While mast cells similarly influenced alveolar polymorphonuclear leukocyte influx, the levels of these cytokines remained largely unaffected in mast cell deficiency. Together, the phenotypes of C3(-/-) mice and Kit(W)/Kit(W-v) mice suggest that complement and mast cells have distinct tissue site-specific requirements acting by apparently distinct mechanisms in the initiation of IC inflammation.

Anatomy of mole external genitalia: Setting the record straight

PubMed Central

Sinclair, Adriane Watkins; Glickman, Stephen; Baskin, Lawrence; Cunha, Gerald R.

2016-01-01

Anatomy of male and female external genitalia of adult mice (Mus musculus) and broad-footed moles (Scapanus latimanus) was re-examined to provide more meaningful anatomical terminology. In the past the perineal appendage of male broad-footed moles has been called the penis, while the female perineal appendage has been given several terms (e.g. clitoris, penile clitoris, peniform clitoris and others). Histological examination demonstrates that perineal appendages of male and female broad-footed moles are the prepuce, which in both sexes are covered externally with a hair-bearing epidermis and lacks erectile bodies. The inner preputial epithelium is non-hair-bearing and defines the preputial space in both sexes. The penis of broad-footed moles lies deep within the preputial space, is an “internal organ” in the resting state and contains the penile urethra, os penis, and erectile bodies. The clitoris of broad-footed moles is defined by a U-shaped clitoral epithelial lamina. Residing within clitoral stroma encompassed by the clitoral epithelial lamina is the corpus cavernosum, blood-filled spaces and the urethra. External genitalia of male and female mice are anatomically similar to that of broad-footed moles with the exception that in female mice the clitoris contains a small os clitoridis and lacks defined erectile bodies, while male mice have an os penis and a prominent distal cartilaginous structure within the male urogenital mating protuberance (MUMP). Clitori of female broad-footed moles lack an os clitoridis but contain defined erectile bodies, while male moles have an os penis similar to the mouse but lack the distal cartilaginous structure. PMID:26694958

IPM Analysis of the Final Mercury and Air Toxics Standards (MATS)

EPA Pesticide Factsheets

EPA used version 4.10_MATS of the Integrated Planning Model (IPM) to analyze the impact of the Mercury and Air Toxics Standards (MATS) rule on the U.S. electric power sector. Learn about the results and view links to documentation.

Environmental Controls on Photosynthetic Microbial Mat Distribution and Morphogenesis on a 3.42 Ga Clastic-Starved Platform

NASA Astrophysics Data System (ADS)

Tice, Michael M.

2009-12-01

All mats are preserved in the shallowest-water interval of those rocks deposited below normal wave base and above storm wave base. This interval is bounded below by a transgressive lag formed during regional flooding and above by a small condensed section that marks a local relative sea-level maximum. Restriction of all mat morphotypes to the shallowest interval of the storm-active layer in the BRC ocean reinforces previous interpretations that these mats were constructed primarily by photosynthetic organisms. Morphotypes α and β dominate the lower half of this interval and grew during deposition of relatively coarse detrital carbonaceous grains, while morphotype γ dominates the upper half and grew during deposition of fine detrital carbonaceous grains. The observed mat distribution suggests that either light intensity or, more likely, small variations in ambient current energy acted as a first-order control on mat morphotype distribution. These results demonstrate significant environmental control on biological morphogenetic processes independent of influences from siliciclastic sedimentation.

Glucocorticoid-induced tethered transrepression requires SUMOylation of GR and formation of a SUMO-SMRT/NCoR1-HDAC3 repressing complex

PubMed Central

Hua, Guoqiang; Ganti, Krishna Priya; Chambon, Pierre

2016-01-01

Upon binding of a glucocorticoid (GC), the GC receptor (GR) can exert one of three transcriptional regulatory functions. We recently reported that SUMOylation of the GR at position K293 in humans (K310 in mice) within the N-terminal domain is indispensable for GC-induced evolutionary conserved inverted repeated negative GC response element (IR nGRE)-mediated direct transrepression. We now demonstrate that the integrity of this GR SUMOylation site is mandatory for the formation of a GR-small ubiquitin-related modifiers (SUMOs)-SMRT/NCoR1-HDAC3 repressing complex, which is indispensable for NF-κB/AP1-mediated GC-induced tethered indirect transrepression in vitro. Using GR K310R mutant mice or mice containing the N-terminal truncated GR isoform GRα-D3 lacking the K310 SUMOylation site, revealed a more severe skin inflammation than in WT mice. Importantly, cotreatment with dexamethasone (Dex) could not efficiently suppress a 12-O-tetradecanoylphorbol-13-acetate (TPA)–induced skin inflammation in these mutant mice, whereas it was clearly decreased in WT mice. In addition, in mice selectively ablated in skin keratinocytes for either nuclear receptor corepressor 1 (NCoR1)/silencing mediator for retinoid or thyroid-hormone receptors (SMRT) corepressors or histone deacetylase 3 (HDAC3), Dex-induced tethered transrepression and the formation of a repressing complex on DNA-bound NF-κB/AP1 were impaired. We previously suggested that GR ligands that would lack both (+)GRE-mediated transactivation and IR nGRE-mediated direct transrepression activities of GCs may preferentially exert the therapeutically beneficial GC antiinflammatory properties. Interestingly, we now identified a nonsteroidal antiinflammatory selective GR agonist (SEGRA) that selectively lacks both Dex-induced (+)GRE-mediated transactivation and IR nGRE-mediated direct transrepression functions, while still exerting a tethered indirect transrepression activity and could therefore be clinically lesser debilitating on long-term GC therapy. PMID:26712006

Lack of P4H-TM in mice results in age-related retinal and renal alterations.

PubMed

Leinonen, Henri; Rossi, Maarit; Salo, Antti M; Tiainen, Päivi; Hyvärinen, Jaana; Pitkänen, Marja; Sormunen, Raija; Miinalainen, Ilkka; Zhang, Chi; Soininen, Raija; Kivirikko, Kari I; Koskelainen, Ari; Tanila, Heikki; Myllyharju, Johanna; Koivunen, Peppi

2016-09-01

Age-related macular degeneration (AMD), affecting the retinal pigment epithelium (RPE), is the leading cause of blindness in middle-aged and older people in developed countries. Genetic and environmental risk factors have been identified, but no effective cure exists. Using a mouse model we show that a transmembrane prolyl 4-hydroxylase (P4H-TM), which participates in the oxygen-dependent regulation of the hypoxia-inducible factor (HIF), is a potential novel candidate gene for AMD. We show that P4h-tm had its highest expression levels in the mouse RPE and brain, heart, lung, skeletal muscle and kidney. P4h-tm -/- mice were fertile and had a normal life span. Lack of P4h-tm stabilized HIF-1α in cortical neurons under normoxia, while in hypoxia it increased the expression of certain HIF target genes in tissues with high endogenous P4h-tm expression levels more than in wild-type mice. Renal erythropoietin levels increased in P4h-tm -/- mice with aging, but the resulting ∼2-fold increase in erythropoietin serum levels did not lead to erythrocytosis. Instead, accumulation of lipid-containing lamellar bodies in renal tubuli was detected in P4h-tm -/- mice with aging, resulting in inflammation and fibrosis, and later glomerular sclerosis and albuminuria. Lack of P4h-tm was associated with retinal thinning, rosette-like infoldings and drusen-like structure accumulation in RPE with aging, as is characteristic of AMD. Photoreceptor recycling was compromised, and electroretinograms revealed functional impairment of the cone pathway in adult P4h-tm -/- mice and cone and rod deficiency in middle-aged mice. P4H-TM is therefore imperative for normal vision, and potentially a novel candidate for age-induced diseases, such as AMD. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Normal hematopoiesis and lack of β-catenin activation in osteoblasts of patients and mice harboring Lrp5 gain-of-function mutations.

PubMed

Galán-Díez, Marta; Isa, Adiba; Ponzetti, Marco; Nielsen, Morten Frost; Kassem, Moustapha; Kousteni, Stavroula

2016-03-01

Osteoblasts are emerging regulators of myeloid malignancies since genetic alterations in them, such as constitutive activation of β-catenin, instigate their appearance. The LDL receptor-related protein 5 (LRP5), initially proposed to be a co-receptor for Wnt proteins, in fact favors bone formation by suppressing gut-serotonin synthesis. This function of Lrp5 occurring in the gut is independent of β-catenin activation in osteoblasts. However, it is unknown whether Lrp5 can act directly in osteoblast to influence other functions that require β-catenin signaling, particularly, the deregulation of hematopoiesis and leukemogenic properties of β-catenin activation in osteoblasts, that lead to development of acute myeloid leukemia (AML). Using mice with gain-of-function (GOF) Lrp5 alleles (Lrp5(A214V)) that recapitulate the human high bone mass (HBM) phenotype, as well as patients with the T253I HBM Lrp5 mutation, we show here that Lrp5 GOF mutations in both humans and mice do not activate β-catenin signaling in osteoblasts. Consistent with a lack of β-catenin activation in their osteoblasts, Lrp5(A214V) mice have normal trilinear hematopoiesis. In contrast to leukemic mice with constitutive activation of β-catenin in osteoblasts (Ctnnb1(CAosb)), accumulation of early myeloid progenitors, a characteristic of AML, myeloid-blasts in blood, and segmented neutrophils or dysplastic megakaryocytes in the bone marrow, are not observed in Lrp5(A214V) mice. Likewise, peripheral blood count analysis in HBM patients showed normal hematopoiesis, normal percentage of myeloid cells, and lack of anemia. We conclude that Lrp5 GOF mutations do not activate β-catenin signaling in osteoblasts. As a result, myeloid lineage differentiation is normal in HBM patients and mice. This article is part of a Special Issue entitled: Tumor Microenvironment Regulation of Cancer Cell Survival, Metastasis, Inflammation, and Immune Surveillance edited by Peter Ruvolo and Gregg L. Semenza. Published by Elsevier B.V.

Impaired long-term memory and NR2A-type NMDA receptor-dependent synaptic plasticity in mice lacking c-Fos in the CNS.

PubMed

Fleischmann, Alexander; Hvalby, Oivind; Jensen, Vidar; Strekalova, Tatyana; Zacher, Christiane; Layer, Liliana E; Kvello, Ane; Reschke, Markus; Spanagel, Rainer; Sprengel, Rolf; Wagner, Erwin F; Gass, Peter

2003-10-08

The immediate early gene c-fos is part of the activator protein-1 transcription factor and has been postulated to participate in the molecular mechanisms of learning and memory. To test this hypothesis in vivo, we generated mice with a nervous system-specific c-fos knock-out using the Cre-loxP system. Adult mice lacking c-Fos in the CNS (c-fosDeltaCNS) showed normal general and emotional behavior but were specifically impaired in hippocampus-dependent spatial and associative learning tasks. These learning deficits correlated with a reduction of long-term potentiation (LTP) in hippocampal CA3-CA1 synapses. The magnitude of LTP was restored by a repeated tetanization procedure, suggesting impaired LTP induction in c-fosDeltaCNS mice. This rescue was blocked by a selective inhibitor of NR2B-type NMDA receptors. This blockade was compensated in wild-type mice by NR2A-type NMDA receptor-activated signaling pathways, thus indicating that these pathways are compromised in c-fosDeltaCNS mice. In summary, our data suggest a role for c-Fos in hippocampus-dependent learning and memory as well as in NMDA receptor-dependent LTP formation.

Temperature-dependant shifts in a wet tropical Hawaiian forest ecosystem: impact on belowground carbon stocks, dynamics, and processes

NASA Astrophysics Data System (ADS)

Crow, S. E.; Litton, C. M.; Giardina, C. P.

2009-12-01

Global patterns suggest a positive correlation between temperature and total belowground carbon (C) flux and partitioning in temperate and tropical regions, but these relationships have yet to be tested within a given ecosystem type. We established a transect of nine permanent forest plots along an elevation gradient (800-1600 m) in native-dominated Metrosideros polymorpha / Acacia koa rainforest developed in volcanic ash soils along the windward slope of Mauna Kea, Hawaii. Along the transect parent material, bedrock age, species composition, and plant available water are nearly constant and only mean annual temperature (MAT) varies substantially (13°C-18°C). We hypothesized that warmer temperatures at lower elevations would drive greater C flux and partitioning to belowground, which represents a direct input of C into belowground stocks. Roots are often sources of stabilized soil organic matter, thus we expected that increased belowground flux and partitioning of C at higher MATs would increase soil C stocks within recalcitrant C pools, even if bulk soil C stock decreases overall. In fact, our data suggest non-linear relationships between temperature and the distribution of C among soil pools based on sequential density fractionation at 1.6 and 2.4 g mL-1, and radiocarbon-based estimates of mean residence time. The proportion of C recovered within the mineral-associated heavy fraction (>2.4 g mL-1) was greatest at the highest MAT (nearly 30% of total soil C), initially declined at the mid-MAT plots (~10% of total soil C), but then increased again at the lowest MAT plots (~25%). Although the proportion of soil C within the heavy fraction was lowest at the mid-MAT plots, the mean residence time of heavy fraction C was greatest in these plots (570-663 yr for the mid-MAT plots versus 120-220 yr for the highest MAT plots and 64-308 for the lowest MAT plots), suggesting that the mineral-associated C in the mid-MAT plots was the most stabilized. In contrast, the proportion of C recovered within the rapidly cycling light fraction (<1.6 g mL-1) initially increased as MAT decreased, from <10% to a peak of nearly 50% of total soil C in the mid-MAT plots, but then decreased again in the plots with lowest MAT. High temperature both directly and indirectly stimulates weathering in these soils-which are thought to be within the phase of maximum nutrient availability, productivity, and potential SOM stabilization during ecosystem development-through increased belowground activity. However, complex feedbacks between temperature, resource allocation, weathering rate, and carbon storage may be driving non-linear relationships between temperature and soil processes.

Tracing biosignatures from the Recent to the Jurassic in sabkha-associated microbial mats

NASA Astrophysics Data System (ADS)

van der Land, Cees; Dutton, Kirsten; Andrade, Luiza; Paul, Andreas; Sherry, Angela; Fender, Tom; Hewett, Guy; Jones, Martin; Lokier, Stephen W.; Head, Ian M.

2017-04-01

Microbial mat ecosystems have been operating at the sediment-fluid interface for over 3400 million years, influencing the flux, transformation and preservation of carbon from the biosphere to the physical environment. These ecosystems are excellent recorders of rapid and profound changes in earth surface environments and biota as they often survive crisis-induced extreme paleoenvironmental conditions. Their biosignatures, captured in the preserved organic matter and the biominerals that form the microbialite rock, constitute a significant tool in understanding geobiological processes and the interactions of the microbial communities with sediments and with the prevailing physical chemical parameters, as well as the environmental conditions at a local and global scale. Nevertheless, the exact pathways of diagenetic organic matter transformation and early-lithification, essential for the accretion and preservation in the geological record as microbialites, are not well understood. The Abu Dhabi coastal sabkha system contains a vast microbial mat belt that is dominated by continuous polygonal and internally-laminated microbial mats across the upper and middle intertidal zones. This modern system is believed to be the best analogue for the Upper Jurassic Arab Formation, which is both a prolific hydrocarbon reservoir and source rock facies in the United Arab Emirates and in neighbouring countries. In order to characterise the processes that lead to the formation of microbialites we investigated the modern and Jurassic system using a multidisciplinary approach, including growth of field-sampled microbial mats under controlled conditions in the laboratory and field-based analysis of microbial communities, mat mineralogy and organic biomarker analysis. In this study, we focus on hydrocarbon biomarker data obtained from the surface of microbial mats actively growing in the intertidal zone of the modern system. By comparing these findings to data obtained from recently-buried, unlithified mats and fully lithified Jurassic mats we are able to identify those biochemical signatures of organic matter preserved in microbialites which survived diagenetic disintegration and represent the primary microbial production. Biomarkers, in the form of alkanes, mono-, di- and trimethylalkanes (MMA, DMA, TMA) were identified in surface and buried mats. Previous studies reported a bimodal distribution of n-Alkanes in the buried mats due to the relatively rapid decline in the abundance of MMAs and DMAs in the C16-C22 range with C24-C45 exclusively found in buried mats, however, this bimodal distribution was not found in our samples. Furthermore, we were able to improve the subsurface facies model for the Jurassic microbialites with our biomarker data as it shows that microbial mats growing in tidal pools or lagoons within the sabkha system form the most prolific hydrocarbon source rocks.

Lack of angiopoietin-like-2 expression limits the metabolic stress induced by a high-fat diet and maintains endothelial function in mice.

PubMed

Yu, Carol; Luo, Xiaoyan; Farhat, Nada; Daneault, Caroline; Duquette, Natacha; Martel, Cécile; Lambert, Jean; Thorin-Trescases, Nathalie; Rosiers, Christine Des; Thorin, Eric

2014-08-15

Angiopoietin-like-2 (angptl2) is produced by several cell types including endothelial cells, adipocytes and macrophages, and contributes to the inflammatory process in cardiovascular diseases. We hypothesized that angptl2 impairs endothelial function, and that lowering angptl2 levels protects the endothelium against high-fat diet (HFD)-induced fat accumulation and hypercholesterolemia. Acute recombinant angptl2 reduced (P<0.05) acetylcholine-mediated vasodilation of isolated wild-type (WT) mouse femoral artery, an effect reversed (P<0.05) by the antioxidant N-acetylcysteine. Accordingly, in angptl2 knockdown (KD) mice, ACh-mediated endothelium-dependent vasodilation was greater (P<0.05) than in WT mice. In arteries from KD mice, prostacyclin contributed to the overall dilation unlike in WT mice. After a 3-month HFD, overall vasodilation was not altered, but dissecting out the endothelial intrinsic pathways revealed that NO production was reduced in arteries isolated from HFD-fed WT mice (P<0.05), while NO release was maintained in KD mice. Similarly, endothelium-derived hyperpolarizing factor (EDHF) was preserved in mesenteric arteries from HFD-fed KD mice but not in those from WT mice. Finally, the HFD increased (P<0.05) total cholesterol-to-high-density lipoprotein ratios, low-density lipoprotein-to-high-density lipoprotein ratios, and leptin levels in WT mice only, while glycemia remained similar in the 2 strains. KD mice displayed less triglyceride accumulation in the liver (P<0.05 versus WT), and adipocyte diameters in mesenteric and epididymal white adipose tissues were smaller (P<0.05) in KD than in WT fed an HFD, while inflammatory gene expression increased (P<0.05) in the fat of WT mice only. Lack of angptl2 expression limits the metabolic stress induced by an HFD and maintains endothelial function in mice. © 2014 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Lack of Angiopoietin‐Like‐2 Expression Limits the Metabolic Stress Induced by a High‐Fat Diet and Maintains Endothelial Function in Mice

PubMed Central

Yu, Carol; Luo, Xiaoyan; Farhat, Nada; Daneault, Caroline; Duquette, Natacha; Martel, Cécile; Lambert, Jean; Thorin‐Trescases, Nathalie; Rosiers, Christine Des; Thorin, Éric

2014-01-01

Background Angiopoietin‐like‐2 (angptl2) is produced by several cell types including endothelial cells, adipocytes and macrophages, and contributes to the inflammatory process in cardiovascular diseases. We hypothesized that angptl2 impairs endothelial function, and that lowering angptl2 levels protects the endothelium against high‐fat diet (HFD)‐induced fat accumulation and hypercholesterolemia. Methods and Results Acute recombinant angptl2 reduced (P<0.05) acetylcholine‐mediated vasodilation of isolated wild‐type (WT) mouse femoral artery, an effect reversed (P<0.05) by the antioxidant N‐acetylcysteine. Accordingly, in angptl2 knockdown (KD) mice, ACh‐mediated endothelium‐dependent vasodilation was greater (P<0.05) than in WT mice. In arteries from KD mice, prostacyclin contributed to the overall dilation unlike in WT mice. After a 3‐month HFD, overall vasodilation was not altered, but dissecting out the endothelial intrinsic pathways revealed that NO production was reduced in arteries isolated from HFD‐fed WT mice (P<0.05), while NO release was maintained in KD mice. Similarly, endothelium‐derived hyperpolarizing factor (EDHF) was preserved in mesenteric arteries from HFD‐fed KD mice but not in those from WT mice. Finally, the HFD increased (P<0.05) total cholesterol–to–high‐density lipoprotein ratios, low‐density lipoprotein–to–high‐density lipoprotein ratios, and leptin levels in WT mice only, while glycemia remained similar in the 2 strains. KD mice displayed less triglyceride accumulation in the liver (P<0.05 versus WT), and adipocyte diameters in mesenteric and epididymal white adipose tissues were smaller (P<0.05) in KD than in WT fed an HFD, while inflammatory gene expression increased (P<0.05) in the fat of WT mice only. Conclusions Lack of angptl2 expression limits the metabolic stress induced by an HFD and maintains endothelial function in mice. PMID:25128474

Effects of feeding ratio of beet pulp to alfalfa hay or grass hay on ruminal mat characteristics and chewing activity in Holstein dry cows.

PubMed

Izumi, Kenichi; Unno, Chigusa

2010-04-01

The influence of the feeding ratio of a non-forage fiber source and hay on ruminal mat characteristics and chewing activity was evaluated in dairy dry cows. Cows were fed four different diets: the ratios of alfalfa hay (AH) to beet pulp (BP) were 8:2 (dry matter basis, A8B2) and 2:8 (A2B8), and those of grass hay (GH) to BP were 8:2 (G8B2) and 2:8 (G2B8). Total eating time was decreased with increasing BP content (P < 0.01). Total rumination time for AH was shorter than that for GH (P < 0.01), and it decreased with increasing BP content (P < 0.01). The ruminal mat was detected by using a penetration resistance test of the rumen digesta. Penetration resistance value (PRV) of ruminal mat was highest with the G8B2 diet and PRV decreased with increasing BP content (P < 0.05) and feeding AH (P < 0.05). Thickness of the ruminal mat was greater for increasing BP content (P < 0.05). Simple linear regression of ruminal mat PRV on total rumination time resulted in a high positive correlation (r = 0.744; P < 0.001; n = 16). The results demonstrated that increasing the PRV of the ruminal mat stimulated rumination activity and a ruminal mat could be formed, although it was soft even when cows were offered a large quantity of BP.

Development of a Twin-Spool Turbofan Engine Simulation Using the Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS)

NASA Technical Reports Server (NTRS)

Zinnecker, Alicia M.; Chapman, Jeffryes W.; Lavelle, Thomas M.; Litt, Jonathan S.

2014-01-01

The Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS) is a tool that has been developed to allow a user to build custom models of systems governed by thermodynamic principles using a template to model each basic process. Validation of this tool in an engine model application was performed through reconstruction of the Commercial Modular Aero-Propulsion System Simulation (C-MAPSS) (v2) using the building blocks from the T-MATS (v1) library. In order to match the two engine models, it was necessary to address differences in several assumptions made in the two modeling approaches. After these modifications were made, validation of the engine model continued by integrating both a steady-state and dynamic iterative solver with the engine plant and comparing results from steady-state and transient simulation of the T-MATS and C-MAPSS models. The results show that the T-MATS engine model was accurate within 3% of the C-MAPSS model, with inaccuracy attributed to the increased dimension of the iterative solver solution space required by the engine model constructed using the T-MATS library. This demonstrates that, given an understanding of the modeling assumptions made in T-MATS and a baseline model, the T-MATS tool provides a viable option for constructing a computational model of a twin-spool turbofan engine that may be used in simulation studies.

Soil nitrogen cycling and availability are linked to ammonia oxidizer abundance across a tropical mean annual temperature gradient

NASA Astrophysics Data System (ADS)

Pierre, S.; Litton, C. M.; Giardina, C. P.; Sparks, J. P.; Groffman, P.; Hewson, I.; Fahey, T.

2016-12-01

Interactions among environmental variables can obfuscate the primary drivers linking soil microbial community function to ecosystem biogeochemistry. These connections are important to understand in order to predict ecosystem responses to global climate change. In particular, the role of mean annual temperature (MAT) in regulating carbon (C) and nitrogen (N) cycling via microbial communities remains unclear. To study these dynamics in situ, we used a a natural elevation gradient of tropical wet montane forest on Mauna Kea, Hawai'i with established permanent plots. Across the gradient, environmental variables besides MAT remain constant. We studied the abundance and activity of the amoA gene, which regulates the rate-limiting step of nitrification, in ammonia oxidizing archaea (AOA) and bacteria (AOB) with relation to N availability and cycling across increasing MAT. Our results show that the abundance of amoA is positively correlated with MAT (p<0.05; r2=0.34) and that MAT and amoA abundance are the primary predictors of nitrate (NO3-) bioavailability (p<0.05). We also found that the relative expression of amoA (cDNA/DNA) is not correlated with MAT or potential net nitrification rate. Our results indicate the direct role of MAT in ammonia oxidizer community structure and demonstrate feedbacks to nutrient availability in forest systems. These findings suggest that forest primary production and carbon cycling may be affected by AOA and AOB responses to rising MAT.

The 2.1-kb inverted repeat DNA sequences flank the mat2,3 silent region in two species of Schizosaccharomyces and are involved in epigenetic silencing in Schizosaccharomyces pombe.

PubMed Central

Singh, Gurjeet; Klar, Amar J S

2002-01-01

The mat2,3 region of the fission yeast Schizosaccharomyces pombe exhibits a phenomenon of transcriptional silencing. This region is flanked by two identical DNA sequence elements, 2.1 kb in length, present in inverted orientation: IRL on the left and IRR on the right of the silent region. The repeats do not encode any ORF. The inverted repeat DNA region is also present in a newly identified related species, which we named S. kambucha. Interestingly, the left and right repeats share perfect identity within a species, but show approximately 2% bases interspecies variation. Deletion of IRL results in variegated expression of markers inserted in the silent region, while deletion of the IRR causes their derepression. When deletions of these repeats were genetically combined with mutations in different trans-acting genes previously shown to cause a partial defect in silencing, only mutations in clr1 and clr3 showed additive defects in silencing with the deletion of IRL. The rate of mat1 switching is also affected by deletion of repeats. The IRL or IRR deletion did not cause significant derepression of the mat2 or mat3 loci. These results implicate repeats for maintaining full repression of the mat2,3 region, for efficient mat1 switching, and further support the notion that multiple pathways cooperate to silence the mat2,3 domain. PMID:12399374

The Reverse Transcriptase/RNA Maturase Protein MatR Is Required for the Splicing of Various Group II Introns in Brassicaceae Mitochondria.

PubMed

Sultan, Laure D; Mileshina, Daria; Grewe, Felix; Rolle, Katarzyna; Abudraham, Sivan; Głodowicz, Paweł; Niazi, Adnan Khan; Keren, Ido; Shevtsov, Sofia; Klipcan, Liron; Barciszewski, Jan; Mower, Jeffrey P; Dietrich, André; Ostersetzer-Biran, Oren

2016-11-01

Group II introns are large catalytic RNAs that are ancestrally related to nuclear spliceosomal introns. Sequences corresponding to group II RNAs are found in many prokaryotes and are particularly prevalent within plants organellar genomes. Proteins encoded within the introns themselves (maturases) facilitate the splicing of their own host pre-RNAs. Mitochondrial introns in plants have diverged considerably in sequence and have lost their maturases. In angiosperms, only a single maturase has been retained in the mitochondrial DNA: the matR gene found within NADH dehydrogenase 1 (nad1) intron 4. Its conservation across land plants and RNA editing events, which restore conserved amino acids, indicates that matR encodes a functional protein. However, the biological role of MatR remains unclear. Here, we performed an in vivo investigation of the roles of MatR in Brassicaceae. Directed knockdown of matR expression via synthetically designed ribozymes altered the processing of various introns, including nad1 i4. Pull-down experiments further indicated that MatR is associated with nad1 i4 and several other intron-containing pre-mRNAs. MatR may thus represent an intermediate link in the gradual evolutionary transition from the intron-specific maturases in bacteria into their versatile spliceosomal descendants in the nucleus. The similarity between maturases and the core spliceosomal Prp8 protein further supports this intriguing theory. © 2016 American Society of Plant Biologists. All rights reserved.

Increasing Mechanical Properties of 2-D-Structured Electrospun Nylon 6 Non-Woven Fiber Mats

PubMed Central

Xiang, Chunhui; Frey, Margaret W.

2016-01-01

Tensile strength, Young’s modulus, and toughness of electrospun nylon 6 non-woven fiber mats were improved by increasing individual nanofiber strength and fiber–fiber load sharing. Single-walled carbon nanotubes (CNTs) were used as reinforcement to increase the strength of the electrospun nylon 6 nanofibers. Young’s modulus, tensile strength, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % solutions increased 51%, 87%, and 136%, respectively, after incorporating 1 wt % CNTs into the nylon 6 nanofibers. Three methods were investigated to enhance fiber–fiber load sharing: increasing friction between fibers, thermal bonding, and solvent bonding. The addition of beaded nylon 6 nanofibers into the non-woven fiber mats to increase fiber-fiber friction resulted in a statistically significantly increase in Young’s modulus over comparable smooth non-woven fiber mats. After annealing, tensile strength, elongation, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % + 10 wt % solutions increased 26%, 28%, and 68% compared to those from 20 wt % solutions. Solvent bonding with formic acid vapor at room temperature for 30 min caused increases of 56%, 67%, and 39% in the Young’s modulus, tensile strength, and toughness of non-woven fiber mats, respectively. The increases attributed to increased individual nanofiber strength and solvent bonding synergistically resulted in the improvement of Young’s modulus of the electrospun nylon 6 non-woven fiber mats. PMID:28773397

Characteristics of thermoregulatory and febrile responses in mice deficient in prostaglandin EP1 and EP3 receptors

PubMed Central

Oka, Takakazu; Oka, Kae; Kobayashi, Takuya; Sugimoto, Yukihiko; Ichikawa, Atsushi; Ushikubi, Fumitaka; Narumiya, Shuh; Saper, Clifford B

2003-01-01

Previous studies have disagreed about whether prostaglandin EP1 or EP3 receptors are critical for producing febrile responses. We therefore injected lipopolysaccharide (LPS) at a variety doses (1 μg kg−1−1 mg kg−1) intraperitoneally (I.P.) into wild-type (WT) mice and mice lacking the EP1 or the EP3 receptors and measured changes in core temperature (Tc) by using telemetry. In WT mice, I.P. injection of LPS at 10 μg kg−1 increased Tc about 1 °C, peaking 2 h after injection. At 100 μg kg−1, LPS increased Tc, peaking 5–8 h after injection. LPS at 1 mg kg−1 decreased Tc, reaching a nadir at 5–8 h after injection. In EP1 receptor knockout (KO) mice injected with 10 μg kg−1 LPS, only the initial (< 40 min) increase in Tc was lacking; with 100 μg kg−1 LPS the mice showed no febrile response. In EP3 receptor KO mice, LPS decreased Tc in a dose- and time-dependent manner. Furthermore, in EP3 receptor KO mice subcutaneous injection of turpentine did not induce fever. Both EP1 and EP3 receptor KO mice showed a normal circadian cycle of Tc and brief hyperthermia following psychological stress (cage-exchange stress and buddy-removal stress). The present study suggests that both the EP1 and the EP3 receptors play a role in fever induced by systemic inflammation but neither EP receptor is involved in the circadian rise in Tc or psychological stress-induced hyperthermia in mice. PMID:12837930

Genetic loss of diazepam binding inhibitor in mice impairs social interest.

PubMed

Ujjainwala, A L; Courtney, C D; Rhoads, S G; Rhodes, J S; Christian, C A

2018-06-01

Neuropsychiatric disorders in which reduced social interest is a common symptom, such as autism, depression, and anxiety, are frequently associated with genetic mutations affecting γ-aminobutyric acid (GABA)ergic transmission. Benzodiazepine treatment, acting via GABA type-A receptors, improves social interaction in male mouse models with autism-like features. The protein diazepam binding inhibitor (DBI) can act as an endogenous benzodiazepine, but a role for DBI in social behavior has not been described. Here, we investigated the role of DBI in the social interest and recognition behavior of mice. The responses of DBI wild-type and knockout male and female mice to ovariectomized female wild-type mice (a neutral social stimulus) were evaluated in a habituation/dishabituation task. Both male and female knockout mice exhibited reduced social interest, and DBI knockout mice lacked the sex difference in social interest levels observed in wild-type mice, in which males showed higher social interest levels than females. The ability to discriminate between familiar and novel stimulus mice (social recognition) was not impaired in DBI-deficient mice of either sex. DBI knockouts could learn a rotarod motor task, and could discriminate between social and nonsocial odors. Both sexes of DBI knockout mice showed increased repetitive grooming behavior, but not in a manner that would account for the decrease in social investigation time. Genetic loss of DBI did not alter seminal vesicle weight, indicating that the social interest phenotype of males lacking DBI is not due to reduced circulating testosterone. Together, these studies show a novel role of DBI in driving social interest and motivation. © 2017 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

Normal tubular regeneration and differentiation of the post-ischemic kidney in mice lacking vimentin.

PubMed Central

Terzi, F.; Maunoury, R.; Colucci-Guyon, E.; Babinet, C.; Federici, P.; Briand, P.; Friedlander, G.

1997-01-01

Proliferation and dedifferentiation of tubular cells are the hallmark of early regeneration after renal ischemic injury. Vimentin, a class III intermediate filament expressed only in mesenchymal cells of mature mammals, was shown to be transiently expressed in post-ischemic renal tubular epithelial cells. Vimentin re-expression was interpreted as a marker of cellular dedifferentiation, but its role in tubular regeneration after renal ischemia has also been hypothesized. This role was evaluated in mice bearing a null mutation of the vimentin gene. Expression of vimentin, proliferating cell nuclear antigen (a marker of cellular proliferation), and villin (a marker of differentiated brush-border membranes) was studied in wild-type (Vim+/+), heterozygous (Vim+/-), and homozygous (Vim-/-) mice subjected to transient ischemia of the left kidney. As expected, vimentin was detected by immunohistochemistry at the basal pole of proximal tubular cells from post-ischemic kidney in Vim+/+ and Vim+/- mice from day 2 to day 28. The expression of the reporter gene beta-galactosidase in Vim+/- and Vim-/- mice confirmed the tubular origin of vimentin. No compensatory expression of keratin could be demonstrated in Vim-/- mice. The intensity of proliferating cell nuclear antigen labeling and the pattern of villin expression were comparable in Vim-/-, Vim+/- and Vim+/+ mice at any time of the study. After 60 days, the structure of post-ischemic kidneys in Vim-/- mice was indistinguishable from that of normal non-operated kidneys in Vim+/+ mice. In conclusion, 1) the pattern of post-ischemic proximal tubular cell proliferation, differentiation, and tubular organization was not impaired in mice lacking vimentin and 2) these results suggest that the transient tubular expression of vimentin is not instrumental in tubular regeneration after renal ischemic injury. Images Figure 1 Figure 2 Figure 3 Figure 5 Figure 6 Figure 7 PMID:9094992

Natriuretic peptides buffer renin-dependent hypertension.

PubMed

Demerath, Theo; Staffel, Janina; Schreiber, Andrea; Valletta, Daniela; Schweda, Frank

2014-06-15

The renin-angiotensin-aldosterone system and cardiac natriuretic peptides [atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP)] are opposing control mechanisms for arterial blood pressure. Accordingly, an inverse relationship between plasma renin concentration (PRC) and ANP exists in most circumstances. However, PRC and ANP levels are both elevated in renovascular hypertension. Because ANP can directly suppress renin release, we used ANP knockout (ANP(-/-)) mice to investigate whether high ANP levels attenuate the increase in PRC in response to renal hypoperfusion, thus buffering renovascular hypertension. ANP(-/-) mice were hypertensive and had reduced PRC compared with that in wild-type ANP(+/+) mice under control conditions. Unilateral renal artery stenosis (2-kidney, 1-clip) for 1 wk induced similar increases in blood pressure and PRC in both genotypes. Unexpectedly, plasma BNP concentrations in ANP(-/-) mice significantly increased in response to two-kidney, one-clip treatment, potentially compensating for the lack of ANP. In fact, in mice lacking guanylyl cyclase A (GC-A(-/-) mice), which is the common receptor for both ANP and BNP, renovascular hypertension was markedly augmented compared with that in wild-type GC-A(+/+) mice. However, the higher blood pressure in GC-A(-/-) mice was not caused by disinhibition of the renin system because PRC and renal renin synthesis were significantly lower in GC-A(-/-) mice than in GC-A(+/+) mice. Thus, natriuretic peptides buffer renal vascular hypertension via renin-independent effects, such as vasorelaxation. The latter possibility is supported by experiments in isolated perfused mouse kidneys, in which physiological concentrations of ANP and BNP elicited renal vasodilatation and attenuated renal vasoconstriction in response to angiotensin II. Copyright © 2014 the American Physiological Society.

Mice lacking liver-specific β-catenin develop steatohepatitis and fibrosis after iron overload.

PubMed

Preziosi, Morgan E; Singh, Sucha; Valore, Erika V; Jung, Grace; Popovic, Branimir; Poddar, Minakshi; Nagarajan, Shanmugam; Ganz, Tomas; Monga, Satdarshan P

2017-08-01

Iron overload disorders such as hereditary hemochromatosis and iron loading anemias are a common cause of morbidity from liver diseases and increase risk of hepatic fibrosis and hepatocellular carcinoma (HCC). Treatment options for iron-induced damage are limited, partly because there is lack of animal models of human disease. Therefore, we investigated the effect of iron overload in liver-specific β-catenin knockout mice (KO), which are susceptible to injury, fibrosis and tumorigenesis following chemical carcinogen exposure. Iron overload diet was administered to KO and littermate control (CON) mice for various times. To ameliorate an oxidant-mediated component of tissue injury, N-Acetyl-L-(+)-cysteine (NAC) was added to drinking water of mice on iron overload diet. KO on iron diet (KO +Fe) exhibited remarkable inflammation, followed by steatosis, oxidative stress, fibrosis, regenerating nodules and occurrence of occasional HCC. Increased injury in KO +Fe was associated with activated protein kinase B (AKT), ERK, and NF-κB, along with reappearance of β-catenin and target gene Cyp2e1, which promoted lipid peroxidation and hepatic damage. Addition of NAC to drinking water protected KO +Fe from hepatic steatosis, injury and fibrosis, and prevented activation of AKT, ERK, NF-κB and reappearance of β-catenin. The absence of hepatic β-catenin predisposes mice to hepatic injury and fibrosis following iron overload, which was reminiscent of hemochromatosis and associated with enhanced steatohepatitis and fibrosis. Disease progression was notably alleviated by antioxidant therapy, which supports its chemopreventive role in the management of chronic iron overload disorders. Lack of animal models for iron overload disorders makes it hard to study the disease process for improving therapies. Feeding high iron diet to mice that lack the β-catenin gene in liver cells led to increased inflammation followed by fat accumulation, cell death and wound healing that mimicked human disease. Administration of an antioxidant prevented hepatic injury in this model. Copyright © 2017 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Loss of MeCP2 in Parvalbumin-and Somatostatin-Expressing Neurons in Mice Leads to Distinct Rett Syndrome-like Phenotypes.

PubMed

Ito-Ishida, Aya; Ure, Kerstin; Chen, Hongmei; Swann, John W; Zoghbi, Huda Y

2015-11-18

Inhibitory neurons are critical for proper brain function, and their dysfunction is implicated in several disorders, including autism, schizophrenia, and Rett syndrome. These neurons are heterogeneous, and it is unclear which subtypes contribute to specific neurological phenotypes. We deleted Mecp2, the mouse homolog of the gene that causes Rett syndrome, from the two most populous subtypes, parvalbumin-positive (PV+) and somatostatin-positive (SOM+) neurons. Loss of MeCP2 partially impairs the affected neuron, allowing us to assess the function of each subtype without profound disruption of neuronal circuitry. We found that mice lacking MeCP2 in either PV+ or SOM+ neurons have distinct, non-overlapping neurological features: mice lacking MeCP2 in PV+ neurons developed motor, sensory, memory, and social deficits, whereas those lacking MeCP2 in SOM+ neurons exhibited seizures and stereotypies. Our findings indicate that PV+ and SOM+ neurons contribute complementary aspects of the Rett phenotype and may have modular roles in regulating specific behaviors. Copyright © 2015 Elsevier Inc. All rights reserved.

Impulsive Choice in Mice Lacking Paternal Expression of Grb10 Suggests Intragenomic Conflict in Behavior.

PubMed

Dent, Claire L; Humby, Trevor; Lewis, Katie; Ward, Andrew; Fischer-Colbrie, Reiner; Wilkinson, Lawrence S; Wilkins, Jon F; Isles, Anthony R

2018-05-01

Imprinted genes are expressed from one parental allele only as a consequence of epigenetic events that take place in the mammalian germ line and are thought to have evolved through intragenomic conflict between parental alleles. We demonstrate, for the first time, oppositional effects of imprinted genes on brain and behavior. Specifically, we show that mice lacking paternal Grb10 make fewer impulsive choices, with no dissociable effects on a separate measure of impulsive action. Taken together with previous work showing that mice lacking maternal Nesp55 make more impulsive choices, this suggests that impulsive choice behavior is a substrate for the action of genomic imprinting. Moreover, the contrasting effect of these two genes suggests that impulsive choices are subject to intragenomic conflict and that maternal and paternal interests pull this behavior in opposite directions. Finally, these data may also indicate that an imbalance in expression of imprinted genes contributes to pathological conditions such as gambling and drug addiction, where impulsive behavior becomes maladaptive. Copyright © 2018 Dent et al.

Using Talking Mats to Support Communication in Persons with Huntington's Disease

ERIC Educational Resources Information Center

Ferm, Ulrika; Sahlin, Anna; Sundin, Linda; Hartelius, Lena

2010-01-01

Background: Many individuals with Huntington's disease experience reduced functioning in cognition, language and communication. Talking Mats is a visually based low technological augmentative communication framework that supports communication in people with different cognitive and communicative disabilities. Aims: To evaluate Talking Mats as a…

M.A.T. Programs.

ERIC Educational Resources Information Center

Wildman, Louis

A proposal is presented for developing a Master of Arts in Teaching (MAT) program at California State University, Bakersfield. The criteria for a MAT program are examined by outlining existing programs at: (1) Harvard Graduate School; (2) University of California, Berkeley; (3) Portland State University; (4) Stanford University; (5) University of…

Photo-assisted generation of phospholipid polymer substrates for regiospecific protein conjugation and control of cell adhesion.

PubMed

Tanaka, Masako; Iwasaki, Yasuhiko

2016-08-01

Novel photo-reactive phospholipid polymers were synthesized for use in the preparation of nonfouling surfaces with protein conjugation capacity. Poly[2-methacryloyloxyethyl phosphorylcholine (MPC)-ran-N-methacryloyl-(l)-tyrosinemethylester (MAT)] (P(MPC/MAT)) was synthesized by conventional radical polymerization, with the MAT units capable of being oxidized by 254nm UV irradiation. Because of this photo-oxidation, active species such as catechol and quinone were alternately generated in the copolymer. A silicon wafer was subjected to surface modification through spin coating of P(MPC/MAT) from an aqueous solution for use as a model substrate. The surface was then irradiated several times with UV light. The thickness of the polymer layers formed on the Si wafers was influenced by various parameters such as polymer concentration, UV irradiation time, and composition of the MAT units in P(MPC/MAT). Oxidized MAT units were advantageous not only for polymer adhesion to a solid surface but also for protein conjugation with the adhered polymers. The amount of protein immobilized on UV-irradiated P(MPC/MAT) was dependent on the composition of the MAT units in the polymer. Furthermore, it was confirmed that protein immobilization on the polymer occurred through the oxidized MAT units because the protein adsorption was significantly reduced upon blocking these units through pretreatment with glycine. Conjugation of regiospecific protein could also be achieved through the use of a photomask. In addition, nonspecific protein adsorption was reduced on the non-irradiated regions whose surface was covered with physisorbed P(MPC/MAT). Therefore, P(MPC/MAT) can be used in the preparation of nonfouling substrates, which enable micrometer-sized manipulation of proteins through photo-irradiation. Function of proteins immobilized on MPC copolymers was also confirmed by cell adhesion test. As such, photo-reactive MPC copolymers are suitable for performing controlled protein conjugation and preparing polymer-protein hybrid platforms for use in biomedical and diagnostic devices. Novel photo-reactive phospholipid polymers have been synthesized for immobilization on solid surfaces and regiospecific protein conjugation. Tyrosine residues embedded in 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymers could be photo-oxidized, resulting in polymers able to form layers on a solid surface and conjugate with proteins. Moreover, nonspecific biofouling on the surface significantly reduced when the oxidized tyrosine units in the polymer layers were blocked. Upon UV irradiation through a photomask, the UV-exposed tyrosine units were selectively oxidized, forming the only specific regions in which protein conjugation could occur. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Dosimetric comparison of 3D conformal, IMRT, and V-MAT techniques for accelerated partial-breast irradiation (APBI)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiu, Jian-Jian; Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai

2014-07-01

The purpose is to dosimetrically compare the following 3 delivery techniques: 3-dimensional conformal radiation therapy (3D-CRT), intensity-modulated arc therapy (IMRT), and volumetric-modulated arc therapy (V-MAT) in the treatment of accelerated partial-breast irradiation (APBI). Overall, 16 patients with T1/2N0 breast cancer were treated with 3D-CRT (multiple, noncoplanar photon fields) on the RTOG 0413 partial-breast trial. These cases were subsequently replanned using static gantry IMRT and V-MAT technology to understand dosimetric differences among these 3 techniques. Several dosimetric parameters were used in plan quality evaluation, including dose conformity index (CI) and dose-volume histogram analysis of normal tissue coverage. Quality assurance studies includingmore » gamma analysis were performed to compare the measured and calculated dose distributions. The IMRT and V-MAT plans gave more conformal target dose distributions than the 3D-CRT plans (p < 0.05 in CI). The volume of ipsilateral breast receiving 5 and 10 Gy was significantly less using the V-MAT technique than with either 3D-CRT or IMRT (p < 0.05). The maximum lung dose and the ipsilateral lung volume receiving 10 (V{sub 10}) or 20 Gy (V{sub 20}) were significantly less with both V-MAT and IMRT (p < 0.05). The IMRT technique was superior to 3D-CRT and V-MAT of low dose distributions in ipsilateral lung (p < 0.05 in V{sub 5} and D{sub 5}). The total mean monitor units (MUs) for V-MAT (621.0 ± 111.9) were 12.2% less than those for 3D-CRT (707.3 ± 130.9) and 46.5% less than those for IMRT (1161.4 ± 315.6) (p < 0.05). The average machine delivery time was 1.5 ± 0.2 minutes for the V-MAT plans, 7.0 ± 1.6 minutes for the 3D-CRT plans, and 11.5 ± 1.9 minutes for the IMRT plans, demonstrating much less delivery time for V-MAT. Based on this preliminary study, V-MAT and IMRT techniques offer improved dose conformity as compared with 3D-CRT techniques without increasing dose to the ipsilateral lung. In terms of MU and delivery time, V-MAT is significantly more efficient for APBI than for conventional 3D-CRT and static-beam IMRT.« less

Disrupting circadian homeostatis of sympathetic signaling promotes tumor development in mice

USDA-ARS?s Scientific Manuscript database

Cell proliferation in all rapidly renewing mammalian tissues follows a circadian rhythm that is often disrupted in advanced-stage tumors. Epidemiologic studies have revealed a clear link between disruption of circadian rhythms and cancer development in humans. Mice lacking the circadian genes Perio...

30 CFR 77.513 - Insulating mats at power switches.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Insulating mats at power switches. 77.513... COAL MINES Electrical Equipment-General § 77.513 Insulating mats at power switches. Dry wooden... switchboards and power-control switches where shock hazards exist. However, metal plates on which a person...

30 CFR 77.513 - Insulating mats at power switches.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Insulating mats at power switches. 77.513... COAL MINES Electrical Equipment-General § 77.513 Insulating mats at power switches. Dry wooden... switchboards and power-control switches where shock hazards exist. However, metal plates on which a person...

30 CFR 77.513 - Insulating mats at power switches.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Insulating mats at power switches. 77.513... COAL MINES Electrical Equipment-General § 77.513 Insulating mats at power switches. Dry wooden... switchboards and power-control switches where shock hazards exist. However, metal plates on which a person...

30 CFR 77.513 - Insulating mats at power switches.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Insulating mats at power switches. 77.513... COAL MINES Electrical Equipment-General § 77.513 Insulating mats at power switches. Dry wooden... switchboards and power-control switches where shock hazards exist. However, metal plates on which a person...

30 CFR 77.513 - Insulating mats at power switches.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Insulating mats at power switches. 77.513... COAL MINES Electrical Equipment-General § 77.513 Insulating mats at power switches. Dry wooden... switchboards and power-control switches where shock hazards exist. However, metal plates on which a person...

Microbial Mats of the Tswaing Impact Crater: Results of a South African Exobiology Expedition and Implications for the Search for Biological Molecules on Mars

NASA Astrophysics Data System (ADS)

Cockell, C. S.; Brandt, D.; Hand, K.; Lee, P.

2001-03-01

We describe microbial mats from the Tswaing impact crater in South Africa. The mats provide insights into the unique biological characteristics of impact craters and can help strategies for the search for biomolecules on Mars.

Compositions of constructed microbial mats

DOEpatents

Bender, Judith A.; Phillips, Peter C.

1999-01-01

Compositions and methods of use of constructed microbial mats, comprising cyanobacteria and purple autotrophic bacteria and an organic nutrient source, in a laminated structure, are described. The constructed microbial mat is used for bioremediation of different individual contaminants and for mixed or multiple contaminants, and for production of beneficial compositions and molecules.

Toxoplasmosis in Sand cats (Felis margarita) and other animals in the Breeding Centre for Endangered Arabian Wildlife in the United Arab Emirates and Al Wabra Wildlife Preservation, the State of Qatar.

PubMed

Dubey, J P; Pas, An; Rajendran, C; Kwok, O C H; Ferreira, L R; Martins, J; Hebel, C; Hammer, S; Su, C

2010-09-20

The Sand cat (Felis margarita) is a small-sized felid found in sand and stone deserts ranging from the north of Africa to Asia, with the Arabian Peninsula as its centre of distribution. The Sand cat captive breeding program at the Breeding Centre for Endangered Arabian Wildlife (BCEAW), Sharjah, UAE, has experienced high newborn mortality rates, and congenital toxoplasmosis was recently recognized as one of the causes of this mortality. In the present study, one 18-month-old Sand cat (FM019) died of acute toxoplasmosis-associated hepatitis and pneumonitis acquired after birth; Toxoplasma gondii was demonstrated in histological sections which reacted with T. gondii polyclonal antibodies by immunohistochemistry (IHC). T. gondii DNA was found by PCR of extracted DNA from liver and lung tissues of this cat. Antibodies to T. gondii were found in serum examined in 1:1600 dilution in the modified agglutination test (MAT); its 2-year-old cage mate seroconverted (MAT titer 1:3200) at the same time. Another Sand cat (FM017) was euthanized because of ill health when 3 years old; its MAT titer was >1:3200, and T. gondii tissue cysts were found in brain, heart, ocular muscles and skeletal muscle, confirmed by IHC. Viable T. gondii was isolated by bioassays in mice inoculated with tissues of another chronically infected Sand cat (FM002); T. gondii was not found in histological sections of this cat. T. gondii antibodies were found in several species of animals tested, notably in 49 of 57 wild felids at BCEAW. A 7-year-old Sand cat (3657) from Al Wabra Wildlife Preservation (AWWP), Doha, State of Qatar died of acute visceral toxoplasmosis with demonstrable T. gondii tachyzoites by IHC, and T. gondii DNA by PCR, and a MAT titer of >3200. T. gondii antibodies were found in 21 of 27 of wild felids at AWWP. PCR-RFLP genotyping at 10 genetic loci revealed that these T. gondii isolates from Sand cat (FM002 and FM019) at BCEAW have an atypical genotype, which was previously reported in T. gondii isolates of dogs from Sri Lanka. The genotype from the cat from AWWP (3657) is a genetic Type II strain with a Type I allele at locus Apico. This is the first report of genetic characterization of T. gondii isolates from Middle East.

Reliability, agreement, and validity of digital weighing scale with MatScan in limb load measurement.

PubMed

Kumar, Senthil N S; Omar, Baharudin; Htwe, Ohnmar; Joseph, Leonard H; Krishnan, Jagannathan; Jafarzedah Esfehani, Ali; Min, Lee L

2014-01-01

Limb loading measurements serve as an objective evaluation of asymmetrical weight bearing in the lower limb. Digital weighing scales (DWSs) could be used in clinical settings for measurement of static limb loading. However, ambiguity exists whether limb loading measurements of DWSs are comparable with a standard tool such as MatScan. A cross-sectional study composed of 33 nondisabled participants was conducted to investigate the reliability, agreement, and validity of DWSs with MatScan in static standing. Amounts of weight distribution and plantar pressure on the individual lower limb were measured using two DWSs (A, B) and MatScan during eyes open (EO) and eyes closed (EC) conditions. The results showed that intra- and interrater reliability (3, 1) were excellent (0.94-0.97) within and between DWS A and B. Bland-Altman plot revealed good agreement between DWS and MatScan in EO and EC conditions. The area under the receiver operating characteristic curve was significant and identified as 0.68 (p = 0.01). The measurements obtained with DWSs are valid and in agreement with MatScan measurements. Hence, DWSs could be used interchangeably with MatScan and could provide clinicians an objective measurement of limb loading suitable for clinical settings.

Sulfate-reducing bacteria and their activities in cyanobacterial mats of Solar Lake (Sinai, Egypt)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teske, A.; Ramsing, N.B.; Habicht, K.

1998-08-01

The sulfate-reducing bacteria within the surface layer of the hypersaline cyanobacterial mat of Solar Lake (Sinai, Egypt) were investigated with combined microbiological, molecular, and biogeochemical approaches. The diurnally oxic surface layer contained between 10{sup 6} and 10{sup 7} cultivable sulfate-reducing bacteria ml{sup {minus}1} day{sup {minus}1}, both in the same range as and sometimes higher than those in anaerobic deeper mat layers. In the oxic surface layer and in the mat layers below, filamentous sulfate-reducing Desulfonema bacteria were found in variable densities of 10{sup 4} and 10{sup 6} cells ml{sup {minus}1}. A Desulfonema-related, diurnally migrating bacterium was detected with PCR andmore » denaturing gradient gel electrophoresis within and below the oxic surface layer. Facultative aerobic respiration, filamentous morphology, motility, diurnal migration, and aggregate formation were the most conspicuous adaptations of Solar Lake sulfate-reducing bacteria to the mat matrix and to diurnal oxygen stress. A comparison of sulfate reduction rates within the mat and previously published photosynthesis rates showed that CO{sub 2} from sulfate reduction in the upper 5 mm accounted for 7 to 8% of the total photosynthetic CO{sub 2} demand of the mat.« less