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Sample records for acid response aar

  1. IGFBP-1 hyperphosphorylation in response to leucine deprivation is mediated by the AAR pathway.

    PubMed

    Malkani, Niyati; Jansson, Thomas; Gupta, Madhulika B

    2015-09-01

    Insulin-like growth factor-1 (IGF-I) is the key regulator of fetal growth. IGF-I bioavailability is markedly diminished by IGF binding protein-1 (IGFBP-1) phosphorylation. Leucine deprivation strongly induces IGFBP-1 hyperphosphorylation, and plays an important role in fetal growth restriction (FGR). FGR is characterized by decreased amino acid availability, which activates the amino acid response (AAR) and inhibits the mechanistic target of rapamycin (mTOR) pathway. We investigated the role of AAR and mTOR in mediating IGFBP-1 secretion and phosphorylation in HepG2 cells in leucine deprivation. mTOR inhibition (rapamycin or raptor + rictor siRNA), or activation (DEPTOR siRNA) demonstrated a role of mTOR in leucine deprivation-induced IGFBP-1 secretion but not phosphorylation. When the AAR was blocked (U0126, or ERK/GCN2 siRNA), both IGFBP-1 secretion and hyperphosphorylation (pSer101/pSer119/pSer169) due to leucine deprivation were prevented. CK2 inhibition by TBB also attenuated IGFBP-1 phosphorylation in leucine deprivation. These results suggest that the AAR and mTOR independently regulate IGFBP-1 secretion and phosphorylation in response to decreased amino acid availability. PMID:25957086

  2. Amino acid deprivation induces CREBZF/Zhangfei expression via an AARE-like element in the promoter.

    PubMed

    Zhang, Yani; Jin, Yaping; Williams, Tegan A; Burtenshaw, Sally M; Martyn, Amanda C; Lu, Rui

    2010-01-15

    CREBZF (also called ZF or Zhangfei) is a basic region-leucine zipper transcription factor that has been implicated in the herpesvirus infection cycle and related cellular processes. Since ATF4 is known to play a key role in cellular responses to various ER stresses as well as amino acid deprivation, we sought to examine the potential involvement of CREBZF in the amino acid response (AAR). We found that the CREBZF protein was induced by amino acid deprivation in the canine MDCK cells. We subsequently cloned a canine CREBZF promoter region (-1767bp to +1bp) that responds to amino acid limitation. Using deletion mapping and site-directed mutagenesis, we identified a 9-bp sequence 5'-ATTCACTCA-3' in the promoter (-1227 to -1219), deletion of which resulted in a complete loss of inducibility by amino acid deprivation. This sequence is similar to the known amino acid response elements (AAREs) found in other AAR-inducible genes, such as CHOP (C/EBP homologous protein, also known as GADD153). These results suggest that CREBZF may be an amino acid stress sensor. Considering the AARE-like sequence found in CREBZF and other similarities between CREBZF and CHOP, we postulate that CREBZF and CHOP may be two sensors that regulate different yet related signaling pathways governing the AAR. PMID:20026304

  3. A regulatory cascade involving AarG, a putative sensor kinase, controls the expression of the 2'-N-acetyltransferase and an intrinsic multiple antibiotic resistance (Mar) response in Providencia stuartii.

    PubMed

    Rather, P N; Paradise, M R; Parojcic, M M; Patel, S

    1998-06-01

    A recessive mutation, aarG1, has been identified that resulted in an 18-fold increase in the expression of beta-galactosidase from an aac(2')-lacZ fusion. Transcriptional fusions and Northern blot analysis demonstrated that the aarG1 allele also resulted in a large increase in the expression of aarP, a gene encoding a transcriptional activator of aac(2')-Ia. The effects of aarG1 on aac(2')-Ia expression were mediated by aarP-dependent and -independent mechanisms. The aarG1 allele also resulted in a multiple antibiotic resistance (Mar) phenotype, which included increased chloramphenicol, tetracycline and fluoroquinolone resistance. This Mar phenotype also resulted from aarP-dependent and -independent mechanisms. Sequence analysis of the aarG locus revealed the presence of two open reading frames, designated aarR and aarG, organized in tandem. The putative AarR protein displayed 75% amino acid identity to the response regulator PhoP, and the AarG protein displayed 57% amino acid identity to the sensor kinase PhoQ. The aarG1 mutation, a C to T substitution, resulted in a threonine to isoleucine substitution at position 279 (T279I) in the putative sensor kinase. The AarG product was functionally similar to PhoQ, as it was able to restore wild-type levels of maganin resistance to a Salmonella typhimurium phoQ mutant. However, expression of the aarP and aac(2')-Ia genes was not significantly affected by the levels of Mg2+ or Ca2+, suggesting that aarG senses a signal other than divalent cations. PMID:9680222

  4. Adult Attachment Ratings (AAR): an item response theory analysis.

    PubMed

    Pilkonis, Paul A; Kim, Yookyung; Yu, Lan; Morse, Jennifer Q

    2014-01-01

    The Adult Attachment Ratings (AAR) include 3 scales for anxious, ambivalent attachment (excessive dependency, interpersonal ambivalence, and compulsive care-giving), 3 for avoidant attachment (rigid self-control, defensive separation, and emotional detachment), and 1 for secure attachment. The scales include items (ranging from 6-16 in their original form) scored by raters using a 3-point format (0 = absent, 1 = present, and 2 = strongly present) and summed to produce a total score. Item response theory (IRT) analyses were conducted with data from 414 participants recruited from psychiatric outpatient, medical, and community settings to identify the most informative items from each scale. The IRT results allowed us to shorten the scales to 5-item versions that are more precise and easier to rate because of their brevity. In general, the effective range of measurement for the scales was 0 to +2 SDs for each of the attachment constructs; that is, from average to high levels of attachment problems. Evidence for convergent and discriminant validity of the scales was investigated by comparing them with the Experiences of Close Relationships-Revised (ECR-R) scale and the Kobak Attachment Q-sort. The best consensus among self-reports on the ECR-R, informant ratings on the ECR-R, and expert judgments on the Q-sort and the AAR emerged for anxious, ambivalent attachment. Given the good psychometric characteristics of the scale for secure attachment, however, this measure alone might provide a simple alternative to more elaborate procedures for some measurement purposes. Conversion tables are provided for the 7 scales to facilitate transformation from raw scores to IRT-calibrated (theta) scores. PMID:24033268

  5. The small RNA Aar in Acinetobacter baylyi: a putative regulator of amino acid metabolism.

    PubMed

    Schilling, Dominik; Findeiss, Sven; Richter, Andreas S; Taylor, Jennifer A; Gerischer, Ulrike

    2010-09-01

    Small non-coding RNAs (sRNAs) are key players in prokaryotic metabolic circuits, allowing the cell to adapt to changing environmental conditions. Regulatory interference by sRNAs in cellular metabolism is often facilitated by the Sm-like protein Hfq. A search for novel sRNAs in A. baylyi intergenic regions was performed by a biocomputational screening. One candidate, Aar, encoded between trpS and sucD showed Hfq dependency in Northern blot analysis. Aar was expressed strongly during stationary growth phase in minimal medium; in contrast, in complex medium, strongest expression was in the exponential growth phase. Whereas over-expression of Aar in trans did not affect bacterial growth, seven mRNA targets predicted by two in silico approaches were upregulated in stationary growth phase. All seven mRNAs are involved in A. baylyi amino acid metabolism. A putative binding site for Lrp, the global regulator of branched-chain amino acids in E. coli, was observed within the aar gene. Both facts imply an Aar participation in amino acid metabolism. PMID:20559624

  6. GAMMA DETECTOR RESPONSE/SOIL CONCENTRATION CORRELATION STUDY AT THE AAR MANUFACTURING, INC. SITE, LIVONIA, MICHIGAN

    SciTech Connect

    ALTIC, NICK A

    2013-03-22

    At the NRC's request, ORAU conducted surveys of the AAR Manufacturing site during the period of September 25 through September 27, 2012. The survey activities included walkover surveys and sampling activities. Once the survey team was onsite, the NRC personnel decided to forgo survey activities in the New Addition and the pickling area. Areas of the planned study boundary were inaccessible due to overgrowth/large pieces of concrete covering the soil surface; therefore, the study boundary was redefined. Gamma walkover scans of the site boundary and front yard identified multiple areas of elevated gamma radiation. As a result, two judgmental samples were collected. Sample results were above thorium background levels The answer to the PSQ relating to the relationship between thorium concentration in soil and NaI instrument response is Yes. NaI instrument response can be used as a predictor of Th-232 concentration in the 0 to 1 m layer. An R2 value of 0.79 was determined for the surface soil relationship, thus satisfying the DQOs. Moreover, the regression was cross-checked by comparing the predicted Th-232 soil core concentration to the average Th-232 concentration (Section 5.3.2). Based on the cross-check, the regression equation provides a reasonable estimate for the Th-232 concentration at the judgmental locations. Consideration must be given when applying this equation to other soil areas of the site. If the contamination was heterogeneously distributed, and not distributed in a discrete layer as it was in the study area, then using the regression equation to predict Th-232 concentration would not be applicable.

  7. Amino acid racemization analysis (AAR) as a successful tool for dating Holocene coastal sediments: Stratigraphy of a barrier island spit (Southern Sylt/North Sea)

    NASA Astrophysics Data System (ADS)

    Tillmann, Tanja; Ziehe, Daniel

    2014-05-01

    Dating of Holocene sediments in shallow coastal areas of the German North Sea by conventional techniques is commonly problematic. In particular the marine reservoir effect of radiocarbon means that radiocarbon dating cannot be applied to sediments younger than about 400 years. Amino acid racemization dating (AAR) is a viable alternative for dating young sediments. The method is based on the determination of ratios of D and L amino acid enantiomers in organic matrices of biogenic carbonates. In this study we use AAR as a tool for dating Holocene barrier islands sediments. Based on an AAR derived chronological framework we develop a model of barrier spit accretion which describes the interaction between extreme events, fair weather coastal processes and sedimentary development that constrains the major episodes of barrier island evolution. The stratigraphy was defined using ground-penetrating radar (GPR) surveys complemented by sedimentological coring data. The stratigraphy is then conceptualised in a AAR chronostratigraphic framework to define a chronological order and allow the development of a stratigraphic model of the evolution of Southern Sylt. The AAR data provide high temporal resolution and have been used for dating stages of barrier spit accretion. The time lines are marked as storm surge generated erosion unconformities in the stratigraphic profile. Individual shells and shell fragments of Cerastoderma edule, Mya arenaria, Mytilus edulis and Scrobicularia plana have been accumulated by short-term storm events as shell layers associated with the erosion unconformities and have been dated by AAR. Time lines reveal that the barrier spit accretion occurred episodically, and is dependant on the provided rate of sand delivery. The general trend is that sequences young to the. South. The AAR derived time lines have been verified and correlated by historic maps and sea charts. It is apparent that spit enlargement at this site increased significantly during the

  8. Reactivity of fluoride dentifrices with artificial caries. III. Quantitative aspects of acquired acid resistance (AAR): F uptake, retention, surface hardening and remineralization.

    PubMed

    White, D J

    1991-01-01

    A pH cycling remineralization/dimineralization model has been used to compare remineralization and acid resistance benefits provided by commercial MFP and NaF dentifrices. Test results show that fluoride dentifrice systems were effective in enhancing lesion remineralization and providing acquired acid resistance (AAR) to carious lesions, with AAR benefits considerably greater in magnitude. Fluoride uptake into the carious lesions was associated with remineralization and AAR benefits. Dentifrices containing the highest levels of soluble ionic fluoride were found most effective in this protocol with MFP dentifrices showing significantly less activity. MFP dentifrice efficacy was enhanced slightly in calcium abrasives. The enhanced activity could be explained by increased levels of background ionic fluoride in the formulations. In contrast to the latter effects, a dual-active NaF+MFP dentifrice in a calcium abrasive system exhibited decreased efficacy relative to a silica abrasive formulation due to incompatibility of free fluoride ion. Comparison of analytical techniques for measurement of AAR in shallow lesions demonstrates that surface microhardness methods match radiographic measures and are thus adequate for ICT measurement of cariogenicity and F remineralization. PMID:1812910

  9. Responses to the AAR-Teagle White Paper: "The Religious Studies Major in a Post-9/11 World"

    ERIC Educational Resources Information Center

    Webster, Jane S.; Buckley, James J.; Jensen, Tim; Floyd-Thomas, Stacey

    2011-01-01

    In October 2008 The American Academy of Religion published the findings of an eighteen month study (conducted with funding from the Teagle Foundation) on "The Religious Studies Major in a Post-9/11 World: New Challenges, New Opportunities." Re-published here, this AAR-Teagle White Paper provides the opportunity for four respondents to raise issues…

  10. Comprehensive profiling of amino acid response uncovers unique methionine-deprived response dependent on intact creatine biosynthesis.

    PubMed

    Tang, Xiaohu; Keenan, Melissa M; Wu, Jianli; Lin, Chih-An; Dubois, Laura; Thompson, J Will; Freedland, Stephen J; Murphy, Susan K; Chi, Jen-Tsan

    2015-04-01

    Besides being building blocks for protein synthesis, amino acids serve a wide variety of cellular functions, including acting as metabolic intermediates for ATP generation and for redox homeostasis. Upon amino acid deprivation, free uncharged tRNAs trigger GCN2-ATF4 to mediate the well-characterized transcriptional amino acid response (AAR). However, it is not clear whether the deprivation of different individual amino acids triggers identical or distinct AARs. Here, we characterized the global transcriptional response upon deprivation of one amino acid at a time. With the exception of glycine, which was not required for the proliferation of MCF7 cells, we found that the deprivation of most amino acids triggered a shared transcriptional response that included the activation of ATF4, p53 and TXNIP. However, there was also significant heterogeneity among different individual AARs. The most dramatic transcriptional response was triggered by methionine deprivation, which activated an extensive and unique response in different cell types. We uncovered that the specific methionine-deprived transcriptional response required creatine biosynthesis. This dependency on creatine biosynthesis was caused by the consumption of S-Adenosyl-L-methionine (SAM) during creatine biosynthesis that helps to deplete SAM under methionine deprivation and reduces histone methylations. As such, the simultaneous deprivation of methionine and sources of creatine biosynthesis (either arginine or glycine) abolished the reduction of histone methylation and the methionine-specific transcriptional response. Arginine-derived ornithine was also required for the complete induction of the methionine-deprived specific gene response. Collectively, our data identify a previously unknown set of heterogeneous amino acid responses and reveal a distinct methionine-deprived transcriptional response that results from the crosstalk of arginine, glycine and methionine metabolism via arginine

  11. Comprehensive Profiling of Amino Acid Response Uncovers Unique Methionine-Deprived Response Dependent on Intact Creatine Biosynthesis

    PubMed Central

    Tang, Xiaohu; Keenan, Melissa M.; Wu, Jianli; Lin, Chih-An; Dubois, Laura; Thompson, J. Will; Freedland, Stephen J.; Murphy, Susan K.; Chi, Jen-Tsan

    2015-01-01

    Besides being building blocks for protein synthesis, amino acids serve a wide variety of cellular functions, including acting as metabolic intermediates for ATP generation and for redox homeostasis. Upon amino acid deprivation, free uncharged tRNAs trigger GCN2-ATF4 to mediate the well-characterized transcriptional amino acid response (AAR). However, it is not clear whether the deprivation of different individual amino acids triggers identical or distinct AARs. Here, we characterized the global transcriptional response upon deprivation of one amino acid at a time. With the exception of glycine, which was not required for the proliferation of MCF7 cells, we found that the deprivation of most amino acids triggered a shared transcriptional response that included the activation of ATF4, p53 and TXNIP. However, there was also significant heterogeneity among different individual AARs. The most dramatic transcriptional response was triggered by methionine deprivation, which activated an extensive and unique response in different cell types. We uncovered that the specific methionine-deprived transcriptional response required creatine biosynthesis. This dependency on creatine biosynthesis was caused by the consumption of S-Adenosyl-L-methionine (SAM) during creatine biosynthesis that helps to deplete SAM under methionine deprivation and reduces histone methylations. As such, the simultaneous deprivation of methionine and sources of creatine biosynthesis (either arginine or glycine) abolished the reduction of histone methylation and the methionine-specific transcriptional response. Arginine-derived ornithine was also required for the complete induction of the methionine-deprived specific gene response. Collectively, our data identify a previously unknown set of heterogeneous amino acid responses and reveal a distinct methionine-deprived transcriptional response that results from the crosstalk of arginine, glycine and methionine metabolism via arginine

  12. Calibration of amino acid racemization (AAR) kinetics in United States mid-Atlantic Coastal Plain Quaternary mollusks using 87Sr/ 86Sr analyses: Evaluation of kinetic models and estimation of regional Late Pleistocene temperature history

    USGS Publications Warehouse

    Wehmiller, J. F.; Harris, W.B.; Boutin, B.S.; Farrell, K.M.

    2012-01-01

    The use of amino acid racemization (AAR) for estimating ages of Quaternary fossils usually requires a combination of kinetic and effective temperature modeling or independent age calibration of analyzed samples. Because of limited availability of calibration samples, age estimates are often based on model extrapolations from single calibration points over wide ranges of D/L values. Here we present paired AAR and 87Sr/ 86Sr results for Pleistocene mollusks from the North Carolina Coastal Plain, USA. 87Sr/ 86Sr age estimates, derived from the lookup table of McArthur et al. [McArthur, J.M., Howarth, R.J., Bailey, T.R., 2001. Strontium isotopic stratigraphy: LOWESS version 3: best fit to the marine Sr-isotopic curve for 0-509 Ma and accompanying Look-up table for deriving numerical age. Journal of Geology 109, 155-169], provide independent age calibration over the full range of amino acid D/L values, thereby allowing comparisons of alternative kinetic models for seven amino acids. The often-used parabolic kinetic model is found to be insufficient to explain the pattern of racemization, although the kinetic pathways for valine racemization and isoleucine epimerization can be closely approximated with this function. Logarithmic and power law regressions more accurately represent the racemization pathways for all amino acids. The reliability of a non-linear model for leucine racemization, developed and refined over the past 20 years, is confirmed by the 87Sr/ 86Sr age results. This age model indicates that the subsurface record (up to 80m thick) of the North Carolina Coastal Plain spans the entire Quaternary, back to ???2.5Ma. The calibrated kinetics derived from this age model yield an estimate of the effective temperature for the study region of 11??2??C., from which we estimate full glacial (Last Glacial Maximum - LGM) temperatures for the region on the order of 7-10??C cooler than present. These temperatures compare favorably with independent paleoclimate information

  13. A mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK)-dependent transcriptional program controls activation of the early growth response 1 (EGR1) gene during amino acid limitation.

    PubMed

    Shan, Jixiu; Balasubramanian, Mukundh N; Donelan, William; Fu, Lingchen; Hayner, Jaclyn; Lopez, Maria-Cecilia; Baker, Henry V; Kilberg, Michael S

    2014-08-29

    Amino acid (AA) limitation in mammalian cells triggers a collection of signaling cascades jointly referred to as the AA response (AAR). In human HepG2 hepatocellular carcinoma, the early growth response 1 (EGR1) gene was induced by either AA deprivation or endoplasmic reticulum stress. AAR-dependent EGR1 activation was discovered to be independent of the well characterized GCN2-ATF4 pathway and instead dependent on MEK-ERK signaling, one of the MAPK pathways. ChIP showed that constitutively bound ELK1 at the EGR1 proximal promoter region was phosphorylated after AAR activation. Increased p-ELK1 binding was associated with increased de novo recruitment of RNA polymerase II to the EGR1 promoter. EGR1 transcription was not induced in HEK293T cells lacking endogenous MEK activity, but overexpression of exogenous constitutively active MEK in HEK293T cells resulted in increased basal and AAR-induced EGR1 expression. ChIP analysis of the human vascular endothelial growth factor A (VEGF-A) gene, a known EGR1-responsive gene, revealed moderate increases in AAR-induced EGR1 binding within the proximal promoter and highly inducible binding to a site within the first intron. Collectively, these data document a novel AA-activated MEK-ERK-ELK1 signaling mechanism. PMID:25028509

  14. A Mitogen-activated Protein Kinase/Extracellular Signal-regulated Kinase Kinase (MEK)-dependent Transcriptional Program Controls Activation of the Early Growth Response 1 (EGR1) Gene during Amino Acid Limitation*

    PubMed Central

    Shan, Jixiu; Balasubramanian, Mukundh N.; Donelan, William; Fu, Lingchen; Hayner, Jaclyn; Lopez, Maria-Cecilia; Baker, Henry V.; Kilberg, Michael S.

    2014-01-01

    Amino acid (AA) limitation in mammalian cells triggers a collection of signaling cascades jointly referred to as the AA response (AAR). In human HepG2 hepatocellular carcinoma, the early growth response 1 (EGR1) gene was induced by either AA deprivation or endoplasmic reticulum stress. AAR-dependent EGR1 activation was discovered to be independent of the well characterized GCN2-ATF4 pathway and instead dependent on MEK-ERK signaling, one of the MAPK pathways. ChIP showed that constitutively bound ELK1 at the EGR1 proximal promoter region was phosphorylated after AAR activation. Increased p-ELK1 binding was associated with increased de novo recruitment of RNA polymerase II to the EGR1 promoter. EGR1 transcription was not induced in HEK293T cells lacking endogenous MEK activity, but overexpression of exogenous constitutively active MEK in HEK293T cells resulted in increased basal and AAR-induced EGR1 expression. ChIP analysis of the human vascular endothelial growth factor A (VEGF-A) gene, a known EGR1-responsive gene, revealed moderate increases in AAR-induced EGR1 binding within the proximal promoter and highly inducible binding to a site within the first intron. Collectively, these data document a novel AA-activated MEK-ERK-ELK1 signaling mechanism. PMID:25028509

  15. aarC, an essential gene involved in density-dependent regulation of the 2'-N-acetyltransferase in Providencia stuartii.

    PubMed Central

    Rather, P N; Solinsky, K A; Paradise, M R; Parojcic, M M

    1997-01-01

    The 2'-N-acetyltransferase [AAC(2')-Ia] in Providencia stuartii has a dual function where it is involved in the acetylation of peptidoglycan and certain aminoglycosides. A search for negative regulators of the aac(2')-Ia gene has resulted in the identification of aarC. A missense allele (aarC1) resulted in an 8.9-fold increase in beta-galactosidase accumulation from an aac(2')-lacZ transcriptional fusion. Northern blot analysis demonstrated an increase in aac(2')-Ia mRNA accumulation that was specific to cells at high density. In addition, the aarC1 allele also resulted in a substantial increase in the expression of aarP, a transcriptional activator of the aac(2')-Ia gene. The wild-type aarC gene was isolated by complementation and encodes a predicted protein of 365 amino acids with a molecular mass of 39,815 Da. The predicted AarC protein exhibited 88% amino acid homology to the previously identified GcpE protein of Escherichia coli and 86% homology to a gene product from Haemophilus influenzae. The E. coli gcpE gene was able to functionally complement the aarC1 allele in P. stuartii. The aarC1 allele was identified as a T to G transversion that resulted in a valine to glycine substitution at position 136 in the AarC protein. The aarC gene appears to be essential for cell viability as construction of a disrupted copy (aarC::lacZ) was possible only in cells that carried an episomal copy of aarC or gcpE. PMID:9079912

  16. ATF4-dependent Regulation of the JMJD3 Gene during Amino Acid Deprivation Can Be Rescued in Atf4-deficient Cells by Inhibition of Deacetylation*

    PubMed Central

    Shan, Jixiu; Fu, Lingchen; Balasubramanian, Mukundh N.; Anthony, Tracy; Kilberg, Michael S.

    2012-01-01

    Following amino acid deprivation, the amino acid response (AAR) induces transcription from specific genes through a collection of signaling mechanisms, including the GCN2-eIF2-ATF4 pathway. The present report documents that the histone demethylase JMJD3 is an activating transcription factor 4 (ATF4)-dependent target gene. The JMJD3 gene contains two AAR-induced promoter activities and chromatin immunoprecipitation (ChIP) analysis showed that the AAR leads to enhanced ATF4 recruitment to the C/EBP-ATF response element (CARE) upstream of Promoter-1. AAR-induced histone modifications across the JMJD3 gene locus occur upon ATF4 binding. Jmjd3 transcription is not induced in Atf4-knock-out cells, but the AAR-dependent activation was rescued by inhibition of histone deacetylation with trichostatin A (TSA). The TSA rescue of AAR activation in the absence of Atf4 also occurred for the Atf3 and C/EBP homology protein (Chop) genes, but not for the asparagine synthetase gene. ChIP analysis of the Jmjd3, Atf3, and Chop genes in Atf4 knock-out cells documented that activation of the AAR in the presence of TSA led to specific changes in acetylation of histone H4. The results suggest that a primary function of ATF4 is to recruit histone acetyltransferase activity to a sub-set of AAR target genes. Thus, absolute binding of ATF4 to these particular genes is not required and no ATF4 interaction with the general transcription machinery is necessary. The data are consistent with the hypothesis that ATF4 functions as a pioneer factor to alter chromatin structure and thus, enhance transcription in a gene-specific manner. PMID:22955275

  17. MAPK signaling triggers transcriptional induction of cFOS during amino acid limitation of HepG2 cells.

    PubMed

    Shan, Jixiu; Donelan, William; Hayner, Jaclyn N; Zhang, Fan; Dudenhausen, Elizabeth E; Kilberg, Michael S

    2015-03-01

    Amino acid (AA) deprivation in mammalian cells activates a collection of signaling cascades known as the AA response (AAR), which is characterized by transcriptional induction of stress-related genes, including FBJ murine osteosarcoma viral oncogene homolog (cFOS). The present study established that the signaling mechanism underlying the AA-dependent transcriptional regulation of the cFOS gene in HepG2 human hepatocellular carcinoma cells is independent of the classic GCN2-eIF2-ATF4 pathway. Instead, a RAS-RAF-MEK-ERK cascade mediates AAR signaling to the cFOS gene. Increased cFOS transcription is observed from 4-24 h after AAR-activation, exhibiting little or no overlap with the rapid and transient increase triggered by the well-known serum response. Furthermore, serum is not required for the AA-responsiveness of the cFOS gene and no phosphorylation of promoter-bound serum response factor (SRF) is observed. The ERK-phosphorylated transcription factor E-twenty six-like (p-ELK1) is increased in its association with the cFOS promoter after activation of the AAR. This research identified cFOS as a target of the AAR and further highlights the importance of AA-responsive MAPK signaling in HepG2 cells. PMID:25523140

  18. Abscisic Acid Synthesis and Response

    PubMed Central

    Finkelstein, Ruth

    2013-01-01

    Abscisic acid (ABA) is one of the “classical” plant hormones, i.e. discovered at least 50 years ago, that regulates many aspects of plant growth and development. This chapter reviews our current understanding of ABA synthesis, metabolism, transport, and signal transduction, emphasizing knowledge gained from studies of Arabidopsis. A combination of genetic, molecular and biochemical studies has identified nearly all of the enzymes involved in ABA metabolism, almost 200 loci regulating ABA response, and thousands of genes regulated by ABA in various contexts. Some of these regulators are implicated in cross-talk with other developmental, environmental or hormonal signals. Specific details of the ABA signaling mechanisms vary among tissues or developmental stages; these are discussed in the context of ABA effects on seed maturation, germination, seedling growth, vegetative stress responses, stomatal regulation, pathogen response, flowering, and senescence. PMID:24273463

  19. The Automated Aircraft Rework System (AARS): A system integration approach

    NASA Technical Reports Server (NTRS)

    Benoit, Michael J.

    1994-01-01

    The Mercer Engineering Research Center (MERC), under contract to the United States Air Force (USAF) since 1989, has been actively involved in providing the Warner Robins Air Logistics Center (WR-ALC) with a robotic workcell designed to perform rework automated defastening and hole location/transfer operations on F-15 wings. This paper describes the activities required to develop and implement this workcell, known as the Automated Aircraft Rework System (AARS). AARS is scheduled to be completely installed and in operation at WR-ALC by September 1994.

  20. Bacillus cereus responses to acid stress.

    PubMed

    Mols, Maarten; Abee, Tjakko

    2011-11-01

    Coping with acid environments is one of the prerequisites for the soil saprophytic and human pathogenic lifestyle of Bacillus cereus. This minireview highlights novel insights in the responses displayed by vegetative cells and germinating spores of B. cereus upon exposure to low pH as well as organic acids, including acetic acid, lactic acid and sorbic acid. Insights regarding the possible acid-inflicted damage, physiological responses and protective mechanisms have been compiled based on single cell fluorescence microscopy, flow cytometry and transcriptome analyses. PMID:21554514

  1. Use of After Action Reports (AARs) to Promote Organizational and Systems Learning in Emergency Preparedness

    PubMed Central

    Savoia, Elena; Agboola, Foluso; Biddinger, Paul D.

    2012-01-01

    Many public health and healthcare organizations use formal knowledge management practices to identify and disseminate the experiences gained over time. The “lessons-learned” approach is one such example of knowledge management practice applied to the wider concept of organizational learning. In the field of emergency preparedness, the lessons-learned approach stands on the assumption that learning from experience improves practice and minimizes avoidable deaths and negative economic and social consequences of disasters. In this project, we performed a structured review of AARs to analyze how lessons learned from the response to real-incidents may be used to maximize knowledge management and quality improvement practices such as the design of public health emergency preparedness (PHEP) exercises. We chose as a source of data the “Lessons Learned Information Sharing (LLIS.gov)” system, a joined program of the U.S. Department of Homeland Security DHS and FEMA that serves as the national, online repository of lessons learned, best practices, and innovative ideas. We identified recurring challenges reported by various states and local public health agencies in the response to different types of incidents. We also strived to identify the limitations of systematic learning that can be achieved due to existing weaknesses in the way AARs are developed. PMID:23066408

  2. Use of after action reports (AARs) to promote organizational and systems learning in emergency preparedness.

    PubMed

    Savoia, Elena; Agboola, Foluso; Biddinger, Paul D

    2012-08-01

    Many public health and healthcare organizations use formal knowledge management practices to identify and disseminate the experiences gained over time. The "lessons-learned" approach is one such example of knowledge management practice applied to the wider concept of organizational learning. In the field of emergency preparedness, the lessons-learned approach stands on the assumption that learning from experience improves practice and minimizes avoidable deaths and negative economic and social consequences of disasters. In this project, we performed a structured review of AARs to analyze how lessons learned from the response to real-incidents may be used to maximize knowledge management and quality improvement practices such as the design of public health emergency preparedness (PHEP) exercises. We chose as a source of data the "Lessons Learned Information Sharing (LLIS.gov)" system, a joined program of the U.S. Department of Homeland Security DHS and FEMA that serves as the national, online repository of lessons learned, best practices, and innovative ideas. We identified recurring challenges reported by various states and local public health agencies in the response to different types of incidents. We also strove to identify the limitations of systematic learning that can be achieved due to existing weaknesses in the way AARs are developed. PMID:23066408

  3. Crystallization and biochemical characterization of the human spliceosomal Aar2-Prp8(RNaseH) complex.

    PubMed

    Santos, Karine; Preussner, Marco; Heroven, Anna Christina; Weber, Gert

    2015-11-01

    In eukaryotes, the removal of nuclear noncoding sequences (pre-mRNA splicing) is catalyzed by the spliceosome, which consists of five ribonucleoprotein particles (U1, U2, U4, U5 and U6 snRNPs, each with a respective snRNA) and a plethora of protein factors that aid spliceosomal maturation, assembly, activation and disassembly. Recently, the U5 snRNP maturation factor Aar2p from baker's yeast has been characterized structurally and biochemically. Aar2p binds to the RNaseH (RH) and Jab1/MPN domains of the highly conserved U5-specific Prp8p, which forms a framework for the spliceosomal catalytic centre. Thereby, Aar2p sterically excludes Brr2p, a helicase essential for the catalytic activation of the spliceosome, from Prp8p binding. At the same time, Aar2p blocks U4/U6 di-snRNA binding to Prp8p. Aar2p therefore prevents premature spliceosome activation and its functions are regulated by reversible phosphorylation. To date, little is known about the hypothetical human Aar2 (hsAar2) orthologue C20ORF4. This study identifies C20ORF4 (i) as part of the HeLa proteome by Western blotting and (ii) as a true Aar2 orthologue which binds to the RH domain (hsRH) of Prp8 and corroborates an evolutionary link between yeast and human Aar2 function. An elaborate strategy was devised to crystallize hsAar2 in complex with hsRH. The analysis of initial weakly diffracting crystals obtained by in situ proteolysis and homology modelling guided the design of an hsAar2 construct in which an internal loop was replaced by three serines (hsAar2(Δloop)). A complex of hsAar2(Δloop) and hsRH crystallized in space group C2; the crystals diffracted to 2.35 Å resolution and were suitable for structure determination by molecular-replacement approaches. The study presented here suggests a connection between Aar2 and the spliceosome in human cells and paves the way for structural studies of human Aar2. PMID:26527271

  4. Animal models of human amino acid responses.

    PubMed

    Baker, David H

    2004-06-01

    The principal differences between experimental animals and humans with regard to amino acid responses are 1) growing animals partition most of their amino acid intake to protein accretion, whereas growing children partition most of their intake to maintenance; 2) invasive assessment procedures are common in animals but very limited in humans; and 3) humans can describe how they feel in response to amino acid levels or balances, whereas animals cannot. New (pharmacologic) uses of amino acids have been and are being discovered (e.g., cysteine, arginine, leucine, glutamine), and this makes it imperative that tolerance limits be established. Work with pigs suggests that excessive intake of methionine and tryptophan present the biggest problems, whereas excessive intake of threonine, glutamate, and the branched-chain amino acids seems to be well tolerated. PMID:15173445

  5. FASD -- De Aar mums get beyond the 'tippling point'.

    PubMed

    Bateman, Chris

    2010-11-01

    When most of the low-income folk in the 'ghost train' town of De Aar began remonstrating with any pregnant mother who was boozing, excited campaigners thought they'd broken through the 'tippling point'. However, their research colleagues proved they'd gone even further -- the dedicated local platoon of social workers, nurses, therapists and volunteers had in three short years reduced the prevalence of fetal alcohol spectrum disorder (FASD) by 30%. This is in a town with the worst recorded FASD prevalence in any single community in the world, where 120 out of every 1 000 residents suffer from FASD (12%). PMID:21081033

  6. Citraturic response to oral citric acid load

    NASA Technical Reports Server (NTRS)

    Sakhaee, K.; Alpern, R.; Poindexter, J.; Pak, C. Y.

    1992-01-01

    It is possible that some orally administered citrate may appear in urine by escaping oxidation in vivo. To determine whether this mechanism contributes to the citraturic response to potassium citrate, we measured serum and urinary citrate for 4 hours after a single oral load of citric acid (40 mEq.) in 6 normal subjects. Since citric acid does not alter acid-base balance, the effect of absorbed citrate could be isolated from that of alkali load. Serum citrate concentration increased significantly (p less than 0.05) 30 minutes after a single oral dose of citric acid and remained significantly elevated for 3 hours after citric acid load. Commensurate with this change, urinary citrate excretion peaked at 2 hours and gradually decreased during the next 2 hours after citric acid load. In contrast, serum and urinary citrate remained unaltered following the control load (no drug). Differences of the citratemic and citraturic effects between phases were significant (p less than 0.05) at 2 and 3 hours. Urinary pH, carbon dioxide pressure, bicarbonate, total carbon dioxide and ammonium did not change at any time after citric acid load, and did not differ between the 2 phases. No significant difference was noted in serum electrolytes, arterialized venous pH and carbon dioxide pressure at any time after citric acid load and between the 2 phases. Thus, the citraturic and citratemic effects of oral citric acid are largely accountable by provision of absorbed citrate, which has escaped in vivo degradation.

  7. Internal structure of the Aar Massif: What can we learn in terms of exploration for deep geothermal energy?

    NASA Astrophysics Data System (ADS)

    Herwegh, Marco; Baumberger, Roland; Wehrens, Philip; Schubert, Raphael; Berger, Alfons; Maeder, Urs; Spillmann, Thomas

    2014-05-01

    The successful use of deep geothermal energy requires 3D flow paths, which allow an efficient heat exchange between the surrounding host rocks and the circulating fluids. Recent attempts to exploit this energy resource clearly demonstrate that the new technology is facing sever problems. Some major problems are related to the prediction of permeability, the 3D structure of the flow paths and the mechanical responses during elevated fluid pressures at depths of several kilometers. Although seemingly new in a technical perspective, nature is facing and solving similar problems since the beginning of the Alpine orogeny. Based on detailed studies in the Hasli Valley (Aar Massif) we can demonstrate that deformation and fluid flow are strongly localized along mechanical anisotropies (e.g. lithological variations, brittle and ductile faults). Some of them already evolved during Variscan and post-Variscan times. Interestingly, these inherited structures are reactivated over and over again during the Alpine orogeny. Their reactivation occurred at depths of ~13-15 km with elevated temperatures (400-475°C) and involved both ductile and brittle deformation processes. Brittle deformation in form of hydrofracking was always present due to the circulating fluids. It is this process, which was and still is responsible for seismic activity. With progressive uplift and exhumation of the Aar Massif, ductile deformation structures became replaced by brittle cataclasites and fault gouges during fault activity at shallower crustal levels. Existing hydrotest data from the Grimsel Test Site (Nagra's underground research laboratory) indicate that these brittle successors of the ductile shear zones are domains of enhanced recent fluid percolation. Note that although being exposed today, the continuation of these fault structures are still active at depth in both brittle and ductile deformation modes, a fact that can be inferred from recent uplift rates and the active seismicity. On the

  8. 76 FR 47612 - AAR Manufacturing, Inc.; Completion of Radiological Survey Activities at CSX Transportation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-05

    ... NRC informed AAR that radioactive thorium surface and subsurface contamination had been detected at... contamination on the CSXT property would result in doses well below NRC's criteria for unrestricted...

  9. Differential Occurrence of Interactions and Interaction Domains in Proteins Containing Homopolymeric Amino Acid Repeats.

    PubMed

    Pelassa, Ilaria; Fiumara, Ferdinando

    2015-01-01

    Homopolymeric amino acids repeats (AARs), which are widespread in proteomes, have often been viewed simply as spacers between protein domains, or even as "junk" sequences with no obvious function but with a potential to cause harm upon expansion as in genetic diseases associated with polyglutamine or polyalanine expansions, including Huntington disease and cleidocranial dysplasia. A growing body of evidence indicates however that at least some AARs can form organized, functional protein structures, and can regulate protein function. In particular, certain AARs can mediate protein-protein interactions, either through homotypic AAR-AAR contacts or through heterotypic contacts with other protein domains. It is still unclear however, whether AARs may have a generalized, proteome-wide role in shaping protein-protein interaction networks. Therefore, we have undertaken here a bioinformatics screening of the human proteome and interactome in search of quantitative evidence of such a role. We first identified the sets of proteins that contain repeats of any one of the 20 amino acids, as well as control sets of proteins chosen at random in the proteome. We then analyzed the connectivity between the proteins of the AAR-containing protein sets and we compared it with that observed in the corresponding control networks. We find evidence for different degrees of connectivity in the different AAR-containing protein networks. Indeed, networks of proteins containing polyglutamine, polyglutamate, polyproline, and other AARs show significantly increased levels of connectivity, whereas networks containing polyleucine and other hydrophobic repeats show lower degrees of connectivity. Furthermore, we observed that numerous protein-protein, -nucleic acid, and -lipid interaction domains are significantly enriched in specific AAR protein groups. These findings support the notion of a generalized, combinatorial role of AARs, together with conventional protein interaction domains, in shaping

  10. Long-term management of AAR-affected structures - An international perspective

    SciTech Connect

    Charlwood, R.G.; Solymar, Z.V.

    1995-12-31

    The objective of the paper is to review international practice and comment on progress made in the long-term management of existing AAR-affected dams and hydroelectric plants. A updated detailed worldwide listing which now includes 104 AAR-affected structures constructed since 1900 will be presented. The listing gives summary data on the year of construction, the year that significant problems were noted, aggregate and cement types, measured expansion rates, test data, time to initial deterioration, duration of reaction, damage to the structures and effects on equipment, and repairs or replacement. A comprehensive bibliography will also be given. Analysis of the database and significant case histories will be used to identify issues affecting dam safety, plant operations, remedial measures and long-term performance of AAR-affected structures. The presentation will be illustrated by several case histories where remedial measures have been implemented.

  11. MicroRNA-16 is putatively involved in the NF-κB pathway regulation in ulcerative colitis through adenosine A2a receptor (A2aAR) mRNA targeting

    PubMed Central

    Tian, Ting; Zhou, Yu; Feng, Xiao; Ye, Shicai; Wang, Hao; Wu, Weiyun; Tan, Wenkai; Yu, Caiyuan; Hu, Juxiang; Zheng, Rong; Chen, Zonghao; Pei, Xinyu; Luo, Hesheng

    2016-01-01

    MicroRNAs (miRNAs) act as important post-transcriptional regulators of gene expression by targeting the 3′-untranslated region of their target genes. Altered expression of miR-16 is reported in human ulcerative colitis (UC), but its role in the development of the disease remains unclear. Adenosine through adenosine A2a receptor (A2aAR) could inhibit nuclear factor-kappaB (NF-κB) signaling pathway in inflammation. Here we identified overexpression of miR-16 and down-regulation of A2aAR in the colonic mucosa of active UC patients. We demonstrated that miR-16 negatively regulated the expression of the A2aAR at the post-transcriptional level. Furthermore, transfection of miR-16 mimics promoted nuclear translocation of NF-κB p65 protein and expression of pro-inflammatory cytokines, IFN-γ and IL-8 in colonic epithelial cells. Treatment with miR-16 inhibitor could reverse these effects in cells. The A2aAR-mediated effects of miR-16 on the activation of the NF-κB signaling pathway were confirmed by the A2aAR knockdown assay. Our results suggest that miR-16 regulated the immune and inflammatory responses, at least in part, by suppressing the expression of the A2aAR to control the activation of the NF-κB signaling pathway. PMID:27476546

  12. Asthmatic responses to airborne acid aerosols.

    PubMed Central

    Ostro, B D; Lipsett, M J; Wiener, M B; Selner, J C

    1991-01-01

    BACKGROUND: Controlled exposure studies suggest that asthmatics may be more sensitive to the respiratory effects of acidic aerosols than individuals without asthma. This study investigates whether acidic aerosols and other air pollutants are associated with respiratory symptoms in free-living asthmatics. METHODS: Daily concentrations of hydrogen ion (H+), nitric acid, fine particulates, sulfates and nitrates were obtained during an intensive air monitoring effort in Denver, Colorado, in the winter of 1987-88. A panel of 207 asthmatics recorded respiratory symptoms, frequency of medication use, and related information in daily diaries. We used a multiple regression time-series model to analyze which air pollutants, if any, were associated with health outcomes reported by study participants. RESULTS: Airborne H+ was found to be significantly associated with several indicators of asthma status, including moderate or severe cough and shortness of breath. Cough was also associated with fine particulates, and shortness of breath with sulfates. Incorporating the participants' time spent outside and exercise intensity into the daily measure of exposure strengthened the association between these pollutants and asthmatic symptoms. Nitric acid and nitrates were not significantly associated with any respiratory symptom analyzed. CONCLUSIONS: In this population of asthmatics, several outdoor air pollutants, particularly airborne acidity, were associated with daily respiratory symptoms. PMID:1851397

  13. Asthmatic responses to airborne acid aerosols

    SciTech Connect

    Ostro, B.D.; Lipsett, M.J.; Wiener, M.B.; Selner, J.C. )

    1991-06-01

    Controlled exposure studies suggest that asthmatics may be more sensitive to the respiratory effects of acidic aerosols than individuals without asthma. This study investigates whether acidic aerosols and other air pollutants are associated with respiratory symptoms in free-living asthmatics. Daily concentrations of hydrogen ion (H+), nitric acid, fine particulates, sulfates and nitrates were obtained during an intensive air monitoring effort in Denver, Colorado, in the winter of 1987-88. A panel of 207 asthmatics recorded respiratory symptoms, frequency of medication use, and related information in daily diaries. We used a multiple regression time-series model to analyze which air pollutants, if any, were associated with health outcomes reported by study participants. Airborne H+ was found to be significantly associated with several indicators of asthma status, including moderate or severe cough and shortness of breath. Cough was also associated with fine particulates, and shortness of breath with sulfates. Incorporating the participants' time spent outside and exercise intensity into the daily measure of exposure strengthened the association between these pollutants and asthmatic symptoms. Nitric acid and nitrates were not significantly associated with any respiratory symptom analyzed. In this population of asthmatics, several outdoor air pollutants, particularly airborne acidity, were associated with daily respiratory symptoms.

  14. Heart Rate Response and Lactic Acid Concentration in Squash Players.

    ERIC Educational Resources Information Center

    Beaudin, Paula; And Others

    1978-01-01

    It was concluded that playing squash is an activity that results in heart rate responses of sufficient intensity to elicit aerobic training effects without producing high lactic acid concentration in the blood. (MM)

  15. Low Phytic Acid Barley Responses to Phosphorus Rates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Low phytic acid (LPA) barley (Hordeum vulgare L.) cultivars partition phosphorus in seed tissue differently than conventional barley cultivars through a reduction in seed phytic acid (myo-inositol-1,2,3,4,5,6-hexkisphosphate) coupled with an increase in inorganic phosphorus. The response of the LPA...

  16. Identification of trends and patterns in sediment geochemistry from the Aare delta plain, Swiss Alps.

    NASA Astrophysics Data System (ADS)

    Carvalho, Filipe; Schulte, Lothar

    2015-04-01

    The study of fluvial systems by means of sediment cores is one of the most interesting approaches to understand the spatial and temporal pattern of river dynamics under the influence of different driving forces such as climate variability and human activities. This work focuses on the analysis of the geochemistry of fluvial sediments from the Aare delta plain in the Swiss Alps.The analysis of sediment cores allowed the identification of trends and patterns in sediment geochemistry. It was possible to identify diverse sedimentation phases in the delta plain, marked by differences in sedimentation processes and characterized by decreasing grain size sequences. It is worth mentioning the importance of peat formations in this sedimentary environment, reaching several centimeters thick in some cases. These horizons are normally associated with very low concentrations of chemical elements from the mineral fraction, such as Si, Al, Fe, and K. The general trends in geochemistry indicate the dominance of elements such as Al and Si, which have similar variability in all cores. It is noted that these elements have a reasonably good correlation with grain size and inverse relation with organic matter content. Factor analysis was used to study the geochemical data set of 3 sediment cores. This analysis is based on a statistical description of the variability of the correlated data where a smaller number of not observed variables are obtained (factors). Factor analysis attempts to find joint variation of the data series and presents that response as unobservable latent variables. In this study, factor analysis was conducted with the major chemical elements: Al, Si, P, K, Ca, Ti, Mn, Fe, Cu, Zn, Pb and also the percentage of TOC. Variations of these 12 inorganic and organic elements are reflected in two unobserved variables, factor 1 and factor 2. Factor analysis has enabled the recognition of two clusters: 1) a group of elements that include the TOC and metals, which are

  17. Perfluorooctanoic Acid Exposure Suppresses T-independent Antibody Responses

    EPA Science Inventory

    Exposure to  3.75mg/kg of perfluoroocatnoic acid (PFOA) for 15d suppresses T-dependent antibody responses (TDAR), suggesting that T helper cells and/or B cells/plasma cells may be impacted. This study evaluated effects of PFOA exposure on the T cell-independent antibody response...

  18. Factors affecting response of surface waters to acidic deposition

    SciTech Connect

    Turner, R.S.; Johnson, D.W.; Elwood, J.W.; Van Winkle, W.; Clapp, R.B.; Reuss, J.O.

    1986-04-01

    Knowledge of watershed hydrology and of the biogeochemical reactions and elemental pools and fluxes occurring in watersheds can be used to classify the response of watersheds and surface waters to acidic deposition. A conceptual mosel is presented for classifying watersheds into those for which (1) surface water chemistry will change rapidly with deposition quality (direct response) (2) surface water chemistry will change only slowly over time (delayed response), and (3) surface water chemistry will not change significantly, even with continued acidic deposition (capacity-protected). Techniques and data available for classification of all watersheds in a region into these categories are discussed.

  19. Polyunsaturated Branched-Chain Fatty Acid Geranylgeranoic Acid Induces Unfolded Protein Response in Human Hepatoma Cells

    PubMed Central

    Iwao, Chieko; Shidoji, Yoshihiro

    2015-01-01

    The acyclic diterpenoid acid geranylgeranoic acid (GGA) has been reported to induce autophagic cell death in several human hepatoma-derived cell lines; however, the molecular mechanism for this remains unknown. In the present study, several diterpenoids were examined for ability to induce XBP1 splicing and/or lipotoxicity for human hepatoma cell lines. Here we show that three groups of diterpenoids emerged: 1) GGA, 2,3-dihydro GGA and 9-cis retinoic acid induce cell death and XBP1 splicing; 2) all-trans retinoic acid induces XBP1 splicing but little cell death; and 3) phytanic acid, phytenic acid and geranylgeraniol induce neither cell death nor XBP1 splicing. GGA-induced ER stress/ unfolded protein response (UPR) and its lipotoxicity were both blocked by co-treatment with oleic acid. The blocking activity of oleic acid for GGA-induced XBP1 splicing was not attenuated by methylation of oleic acid. These findings strongly suggest that GGA at micromolar concentrations induces the so-called lipid-induced ER stress response/UPR, which is oleate-suppressive, and shows its lipotoxicity in human hepatoma cells. PMID:26186544

  20. Landing responses of Anopheles gambiae elicited by oxocarboxylic acids.

    PubMed

    Healy, T P; Copland, M J W; Cork, A; Przyborowska, A; Halket, J M

    2002-06-01

    A wind tunnel bioassay and video system were used to observe Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) landing on glass cylinders, heated to human skin temperature (34 degrees C) and treated with aqueous solutions of oxocarboxylic acids. Six of nine compounds tested: 2-oxobutanoic, 2-oxo-3-methylbutanoic, 2-oxopentanoic, 2-oxo-3-methylpentanoic, 2-oxo-4-methylpentanoic and 2-oxohexanoic elicited significant landing responses in comparison to a water control. Landing responses appeared to be restricted to C4-C6, 2-oxocarboxylic acids. A solution of 1 microg/microL of 2-oxopentanoic acid elicited the highest level of response that was temperature dependent: significant numbers of landings occurred only within +/-2 degrees C of human skin temperature. Chemical analysis by linked gas-liquid chromatography/mass spectrometry of methyl-oxime, trimethylsilyl derivatized samples of human sweat extracts revealed the presence of 2-oxopropanoic (pyruvic) acid and three behaviourally active, branched chain acids: 2-oxo-3-methylbutanoic, 2-oxo-3-methylpentanoic and 2-oxo-4-methylpentanoic. PMID:12109705

  1. The acid tolerance response of Salmonella typhimurium involves transient synthesis of key acid shock proteins.

    PubMed Central

    Foster, J W

    1993-01-01

    Although Salmonella typhimurium prefers neutral-pH environments, it can adapt to survive conditions of severe low-pH stress (pH 3.3). The process, termed the acid tolerance response (ATR), includes two distinct stages. The first stage, called pre-acid shock, is induced at pH 5.8 and involves the production of an inducible pH homeostasis system functional at external pH values below 4.0. The second stage occurs following an acid shock shift to pH 4.5 or below and is called the post-acid shock stage. During this stage of the ATR, 43 acid shock proteins (ASPs) are synthesized. The present data reveal that several ASPs important for pH 3.3 acid tolerance are only transiently produced. Their disappearance after 30 to 40 min of pH 4.4 acid shock coincides with an inability to survive subsequent pH 3.3 acid challenge. Clearly, an essential feature of inducible acid tolerance is an ability to synthesize these key ASPs. The pre-acid shock stage, with its inducible pH homeostasis system, offers the cell an enhanced ability to synthesize ASPs following rapid shifts to conditions below pH 4.0, an external pH that normally prevents ASP synthesis. The data also address possible signals for ASP synthesis. The inducing signal for 22 ASPs appears to be internal acidification, while external pH serves to induce 13 others. Of the 14 transient ASPs, 10 are induced in response to changes in internal pH. Mutations in the fur (ferric uptake regulator) locus that produce an Atr- acid-sensitive phenotype also eliminate induction of six transiently induced ASPs. Images PMID:8458840

  2. SPODOSOL VARIABILITY AND ASSESSMENT OF RESPONSE TO ACIDIC DEPOSITION

    EPA Science Inventory

    Variability in forest soils makes it difficult to observe short-term changes in chemical properties under field conditions. uried soil-bag technique was developed to examine the chemical response of a Maine forest soil to loadings of strong acids (HNO3 and H2SO4). cids were added...

  3. TRANSCRIPTIONAL RESPONSES OF MOUSE EMBRYO CULTURES EXPOSED TO BROMOCHLOROACETIC ACID

    EPA Science Inventory

    Transcriptional responses of mouse embryo cultures exposed to bromochloroacetic acid

    Edward D. Karoly?*, Judith E. Schmid* and E. Sidney Hunter III*
    ?Curriculum in Toxicology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina and *Reproductive Tox...

  4. Omega-3 fatty acids modulate neonatal cytokine response to endotoxin.

    PubMed

    Espiritu, Michael M; Lin, Hong; Foley, Elizabeth; Tsang, Valerie; Rhee, Eunice; Perlman, Jeffrey; Cunningham-Rundles, Susanna

    2016-08-01

    Neonatal immune response is characterized by an uncompensated pro-inflammatory response that can lead to inflammation-related morbidity and increased susceptibility to infection. We investigated the effects of long-chain n-3 polyunsaturated fatty acids (n-3 PUFAs) docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA) pre-treatment on cytokine secretion to low-concentration endotoxin (lipopolysaccharide, LPS) in THP-1 monocytes and neonatal cord blood (CB) from healthy full-term infants. Pre-treatment of THP-1 cells, with either n-3 PUFA at 25 or 100 μM significantly reduced IL-6, IL-10, and IL-12 secretion while DHA, but not EPA, reduced TNF-α response to LPS. DHA inhibition was stronger compared to EPA and effective at the low concentration. The same concentrations of n-3 PUFAs inhibited IL-12 but not IL-10 cytokine response in whole CB from 9 infants pre-treated for 24 h. To assess clinical relevance for acute response to LPS, the effects of low-concentration DHA at 25 μM or 12.5 μM were assessed before and after LPS exposure of isolated CB mononuclear cells from 20 infants for 1 h. When added before or after LPS, physiologic DHA treatment produced significant concentration-dependent inhibition of TNF-α, IL-6, IL-1β, and IL-8 secretion. The results demonstrate prophylactic and therapeutic modulation of neonatal cytokine response to LPS and provide proof-of-concept that low-concentration administration of n-3 PUFA could attenuate or resolve neonatal inflammatory response. PMID:26812855

  5. Presynaptic gamma-aminobutyric acid responses in the olfactory cortex.

    PubMed Central

    Pickles, H G

    1979-01-01

    1. Potential changes were recorded from the lateral olfactory tract in slices of rat olfactory cortex in vitro at room temperature. 2. Superfused gamma-aminobutyric acid (GABA) usually produced dose-related depolarization of the lateral olfactory tract. Muscimol and 3-aminopropanesulphonic acid appeared more potent depolarizing agents than GABA, and glycine and taurine appeared less potent. Carbachol and glutamate were virtually ineffective. 3. The GABA responses were at least partially Cl- dependent. 4. (+)-Bicuculline and higher concentrations of strychnine antagonized the GABA but not the glycine-induced depolarizations. Paradoxically, responses to high doses of GABA were sometimes potentiated by both bicuculline and strychnine. 5. It is suggested that GABA receptors could occur as widely on nerve terminals as they do postsynaptically in the CNS, where GABA could be involved in the modulation of transmitter output. PMID:760898

  6. Genome analysis of Excretory/Secretory proteins in Taenia solium reveals their Abundance of Antigenic Regions (AAR).

    PubMed

    Gomez, Sandra; Adalid-Peralta, Laura; Palafox-Fonseca, Hector; Cantu-Robles, Vito Adrian; Soberón, Xavier; Sciutto, Edda; Fragoso, Gladis; Bobes, Raúl J; Laclette, Juan P; Yauner, Luis del Pozo; Ochoa-Leyva, Adrián

    2015-01-01

    Excretory/Secretory (ES) proteins play an important role in the host-parasite interactions. Experimental identification of ES proteins is time-consuming and expensive. Alternative bioinformatics approaches are cost-effective and can be used to prioritize the experimental analysis of therapeutic targets for parasitic diseases. Here we predicted and functionally annotated the ES proteins in T. solium genome using an integration of bioinformatics tools. Additionally, we developed a novel measurement to evaluate the potential antigenicity of T. solium secretome using sequence length and number of antigenic regions of ES proteins. This measurement was formalized as the Abundance of Antigenic Regions (AAR) value. AAR value for secretome showed a similar value to that obtained for a set of experimentally determined antigenic proteins and was different to the calculated value for the non-ES proteins of T. solium genome. Furthermore, we calculated the AAR values for known helminth secretomes and they were similar to that obtained for T. solium. The results reveal the utility of AAR value as a novel genomic measurement to evaluate the potential antigenicity of secretomes. This comprehensive analysis of T. solium secretome provides functional information for future experimental studies, including the identification of novel ES proteins of therapeutic, diagnosis and immunological interest. PMID:25989346

  7. Genome analysis of Excretory/Secretory proteins in Taenia solium reveals their Abundance of Antigenic Regions (AAR)

    PubMed Central

    Gomez, Sandra; Adalid-Peralta, Laura; Palafox-Fonseca, Hector; Cantu-Robles, Vito Adrian; Soberón, Xavier; Sciutto, Edda; Fragoso, Gladis; Bobes, Raúl J.; Laclette, Juan P.; Yauner, Luis del Pozo; Ochoa-Leyva, Adrián

    2015-01-01

    Excretory/Secretory (ES) proteins play an important role in the host-parasite interactions. Experimental identification of ES proteins is time-consuming and expensive. Alternative bioinformatics approaches are cost-effective and can be used to prioritize the experimental analysis of therapeutic targets for parasitic diseases. Here we predicted and functionally annotated the ES proteins in T. solium genome using an integration of bioinformatics tools. Additionally, we developed a novel measurement to evaluate the potential antigenicity of T. solium secretome using sequence length and number of antigenic regions of ES proteins. This measurement was formalized as the Abundance of Antigenic Regions (AAR) value. AAR value for secretome showed a similar value to that obtained for a set of experimentally determined antigenic proteins and was different to the calculated value for the non-ES proteins of T. solium genome. Furthermore, we calculated the AAR values for known helminth secretomes and they were similar to that obtained for T. solium. The results reveal the utility of AAR value as a novel genomic measurement to evaluate the potential antigenicity of secretomes. This comprehensive analysis of T. solium secretome provides functional information for future experimental studies, including the identification of novel ES proteins of therapeutic, diagnosis and immunological interest. PMID:25989346

  8. A NASA F/A-18, participating in the Automated Aerial Refueling (AAR) project, flies over the Dryden

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A NASA F/A-18 is participating in the Automated Aerial Refueling (AAR) project. The 300-gallon aerial refueling store seen on the belly of the aircraft carries fuel and a refueling drogue. This aircraft acts as a tanker in the study to develop an aerodynamic model for future automated aerial refueling, especially of unmanned vehicles.

  9. Halogen and trace element geochemistry in Mid-Ocean Ridge basalts from the Australian-Antarctic Ridge (AAR)

    NASA Astrophysics Data System (ADS)

    Yang, Y. S.; Seo, J. H.; Park, S. H.; Kim, T.

    2015-12-01

    Australian-Antarctic Ridge (AAR) is an extension of easternmost SE Indian Mid-Ocean Ridge (MOR).We collected volcanic glasses from the "in-axis" of the KR1 and KR2 MOR, and the overlapping zones of the KR1 MOR and the nearby seamounts ("KR1 mixing"). We determined trace and halogen elements in the glasses. Halogen concentrations and its ratios in the glasses are important to understand the mantle metasomatism and volatile recycling. 52 of the collected glasses are "primitive" (higher than 6 wt% MgO), while 3 of them have rather "evolved" composition (MgO wt% of 1.72, 2.95 and 4.15). K2O concentrations and Th/Sc ratios in the glasses show a negative correlation with its MgO concentration. Incompatible element ratios such as La/Sm are rather immobile during a magma differentiation so the ratios are important to understand mantle composition (Hofmann et al. 2003). La/Sm ratios in the glasses are 0.95 ~ 3.28 suggesting that the AAR basalts can be classified into T-MORB and E-MORB (Schilling et al., 1983). La/Sm ratios are well-correlated with incompatible elements such as U, Ba, Nb, and negatively correlated with compatible elements such as Sc, Eu2+, Mg. The AAR glasses contain detectable halogen elements. The "KR1 mixing" glasses in halogen elements are more abundant than "in-axis" the glasses. Cl is the least variable element compared to the other halogens such as Br and I in the AAR. The "KR1 mixing" glasses have the largest variations of Br/Cl ratios compared to the "in-axis" glasses. The Cl/Br and Th/Sc ratios in the "in-axis" glasses and in the "KR1 mixing" glasses show positive and negative correlations, respectively. The Br-rich glasses in the "KR1 mixing" zone might be explained by a recycled Br-rich oceanic slab of paleo-subduction or by a hydrothermal alteration in the AAR. I composition in the glasses does not show a correlation other trace elements. The K/Cl and K/Ti ratios in the AAR glasses are similar to the basalts from the Galapagos Spreading Center

  10. The Front of the Aar Massif: A Crustal-Scale Ramp Anticline?

    NASA Astrophysics Data System (ADS)

    Herwegh, Marco; Mock, Samuel; Wehrens, Philip; Baumberger, Roland; Berger, Alfons; Wangenheim, Cornelia; Glotzbach, Christoph; Kissling, Edi

    2015-04-01

    The front of the Aar Massif (Swiss Central Alps) is characterized by Paleozoic basement rocks exposed at altitudes of more than 4600m above sea level, followed by a steeply north dipping Mesozoic sedimentary cover and overlying Helvetic nappes. The sediments turn into subhorizontal orientations just few kilometers to the N, where the top of the basement is situated at depths of about 7000m below sea level. What is the origin of this vertical jump of about 12000m of the basement rocks over such short horizontal distances? Recent structural investigations at the Basement-Cover contact indicate a complex structural evolution involving reactivation of extensional faults and inversion of half-grabens during early compressional stages. In the internal parts of the Aar Massif a general steepening of the faults resulted with progressive compression. In the northern frontal part, however, a new spaced cleavage evolved, which is dipping with 20-30° to the SE. In places, the new cleavage in the basement rocks is intense and pervasive and correlates with a steepening of the basement-cover contact and its offsets of several tens to hundreds of meters. Hence strain is strongly partitioned in a large number of high strain zones, which cover a cumulative thickness of at least 2000m, eventually even much more considering subsurface continuation. The Mesozoic sediments affected by this large-scale deformation zone are either intensely ductile folded in the case of limestones or faulted and imbricated in the case of dolomites. These differences in deformation style result from the deformation conditions of about < 250-300°C, where calcite still deforms in a ductile manner, while dolomite and crystalline basement preferentially undergo brittle deformation in combination of dissolution-precipitation processes. In a large-scale point of view, we suggest that the high strain domain in the crystalline basement in fact represents a crustal-scale several kilometers wide shear zone, which

  11. Arabidopsis YAK1 regulates abscisic acid response and drought resistance.

    PubMed

    Kim, Dongjin; Ntui, Valentine Otang; Xiong, Liming

    2016-07-01

    Abscisic acid (ABA) is an important phytohormone that controls several plant processes such as seed germination, seedling growth, and abiotic stress response. Here, we report that AtYak1 plays an important role in ABA signaling and postgermination growth in Arabidopsis. AtYak1 knockout mutant plants were hyposensitive to ABA inhibition of seed germination, cotyledon greening, seedling growth, and stomatal movement. atyak1-1 mutant plants display reduced drought stress resistance, as evidenced by water loss rate and survival rate. Molecular genetic analysis revealed that AtYak1 deficiency led to elevated expression of stomatal-related gene, MYB60, and down-regulation of several stress-responsive genes. Altogether, these results indicate that AtYak1 plays a role as a positive regulator in ABA-mediated drought response in Arabidopsis. PMID:27264339

  12. Lactic acid delays the inflammatory response of human monocytes

    SciTech Connect

    Peter, Katrin; Rehli, Michael; Singer, Katrin; Renner-Sattler, Kathrin; Kreutz, Marina

    2015-02-13

    Lactic acid (LA) accumulates under inflammatory conditions, e.g. in wounds or tumors, and influences local immune cell functions. We previously noted inhibitory effects of LA on glycolysis and TNF secretion of human LPS-stimulated monocytes. Here, we globally analyze the influence of LA on gene expression during monocyte activation. To separate LA-specific from lactate- or pH-effects, monocytes were treated for one or four hours with LPS in the presence of physiological concentrations of LA, sodium lactate (NaL) or acidic pH. Analyses of global gene expression profiles revealed striking effects of LA during the early stimulation phase. Up-regulation of most LPS-induced genes was significantly delayed in the presence of LA, while this inhibitory effect was attenuated in acidified samples and not detected after incubation with NaL. LA targets included genes encoding for important monocyte effector proteins like cytokines (e.g. TNF and IL-23) or chemokines (e.g. CCL2 and CCL7). LA effects were validated for several targets by quantitative RT-PCR and/or ELISA. Further analysis of LPS-signaling pathways revealed that LA delayed the phosphorylation of protein kinase B (AKT) as well as the degradation of IκBα. Consistently, the LPS-induced nuclear accumulation of NFκB was also diminished in response to LA. These results indicate that the broad effect of LA on gene expression and function of human monocytes is at least partially caused by its interference with immediate signal transduction events after activation. This mechanism might contribute to monocyte suppression in the tumor environment. - Highlights: • Lactic acid broadly delays LPS-induced gene expression in human monocytes. • Expression of important monocyte effector molecules is affected by lactic acid. • Interference of lactic acid with TLR signaling causes the delayed gene expression. • The profound effect of lactic acid might contribute to immune suppression in tumors.

  13. Collaborative effort to model plant response to acidic rain

    SciTech Connect

    Jacobson, J.; Kuja, A.; Shriner, D.; Perrigan, S.; Irving, P.; Lee, J.; Troiano, J.; Cullinan, V.

    1988-06-01

    Radish plants were exposed three times per week to simulated acidic rain at pH values of 2.6 to 5.4 over the course of four weeks in trials performed at Argonne, Illinois; Ithaca and Upton, New York; Corvallis, Oregon; Oak Ridge, Tennessee; and Toronto, Canada. Uniform genotype, soil media and planting techniques, treatment procedures, biological measurements, and experimental design were employed. Growth of plants differed among trials as a result of variation in greenhouse environmental conditions according to location and facilities. Larger plants underwent greater absolute but lower relative reductions in biomass after exposure to the higher levels of acidity. A generalized Mitscherlich function was used to model the effects of acidity of simulated rain or dry mass of hypocotyls using data from three laboratories that performed duplicate trials. The remaining data, from three other laboratories that performed only one trial each, were used to test the model. When the laboratory by trial effect was removed, lack of fit to the Mitscherlich function was insignificant. Thus, a single mathematical model satisfactorily characterized the relationship between acidity and mean plant response.

  14. Acidic chitinase primes the protective immune response to gastrointestinal nematodes.

    PubMed

    Vannella, Kevin M; Ramalingam, Thirumalai R; Hart, Kevin M; de Queiroz Prado, Rafael; Sciurba, Joshua; Barron, Luke; Borthwick, Lee A; Smith, Allen D; Mentink-Kane, Margaret; White, Sandra; Thompson, Robert W; Cheever, Allen W; Bock, Kevin; Moore, Ian; Fitz, Lori J; Urban, Joseph F; Wynn, Thomas A

    2016-05-01

    Acidic mammalian chitinase (AMCase) is known to be induced by allergens and helminths, yet its role in immunity is unclear. Using AMCase-deficient mice, we show that AMCase deficiency reduced the number of group 2 innate lymphoid cells during allergen challenge but was not required for establishment of type 2 inflammation in the lung in response to allergens or helminths. In contrast, AMCase-deficient mice showed a profound defect in type 2 immunity following infection with the chitin-containing gastrointestinal nematodes Nippostrongylus brasiliensis and Heligmosomoides polygyrus bakeri. The impaired immunity was associated with reduced mucus production and decreased intestinal expression of the signature type 2 response genes Il13, Chil3, Retnlb, and Clca1. CD103(+) dendritic cells, which regulate T cell homing, were also reduced in mesenteric lymph nodes of infected AMCase-deficient mice. Thus, AMCase functions as a critical initiator of protective type 2 responses to intestinal nematodes but is largely dispensable for allergic responses in the lung. PMID:27043413

  15. Adaptive acid tolerance response of Vibrio parahaemolyticus as affected by acid adaptation conditions, growth phase, and bacterial strains.

    PubMed

    Chiang, Ming-Lun; Chou, Cheng-Chun; Chen, Hsi-Chia; Tseng, Yu-Ting; Chen, Ming-Ju

    2012-08-01

    Vibrio parahaemolyticus strain 690 was isolated from gastroenteritis patients. Its thermal and ethanol stress responses have been reported in our previous studies. In this study, we further investigated the effects of various acid adaptation conditions including pH (5.0-6.0) and time (30-90 min) on the acid tolerance in different growth phases of V. parahaemolyticus 690. Additionally, the adaptive acid tolerance among different V. parahaemolyticus strains was compared. Results indicated that the acid tolerance of V. parahaemolyticus 690 was significantly increased after acid adaptation at pH 5.5 and 6.0 for 30-90 min. Among the various acid adaptation conditions examined, V. parahaemolyticus 690 acid-adapted at pH 5.5 for 90 min exhibited the highest acid tolerance. The acid adaptation also influenced the acid tolerance of V. parahaemolyticus 690 in different growth phases with late-exponential phase demonstrating the greatest acid tolerance response (ATR) than other phases. Additionally, the results also showed that the induction of adaptive ATR varied with different strains of V. parahaemolyticus. An increase in acid tolerance of V. parahaemolyticus was observed after prior acid adaptation in five strains (556, 690, BCRC 13023, BCRC 13025, and BCRC 12864), but not in strains 405 and BCRC 12863. PMID:22827515

  16. Lake Biel Holocene sediment record before and after the Aare river deviation (1878 AD)

    NASA Astrophysics Data System (ADS)

    Jeannet, Alice; Corella, Juan Pablo; Kremer, Katrina; Girardclos, Stéphanie

    2014-05-01

    Lake sediments are excellent archives of environmental and climate changes as well as human impact on lake- and river-systems. Lake Biel is a medium-sized peri-alpine lake in Switzerland, with a maximum depth of 74 m, and lies at an altitude of 429 m a.s.l. Lake Biel, which formed during the Pleistocene by glacial erosion, is part of the Aare river system. Our study focuses on the south-west part of the lake basin where the lake sedimentation was originally (i.e. naturally) mainly controlled by autochthonous sedimentation. This area is currently under a strong influence of water and sediment input from this river catchment since the Aare river deviation through the Hagneck canal in 1878. A 10.05 m long composite sediment sequence, cored from a 52 m water depth in September 2011, was built from two long cores retrieved with the ETH Zurich/Eawag Uwitec system. A radiocarbon age model indicates that the retrieved sedimentary sequence spans the last 7500 years. The upper sediments were correlated to previous short core radionuclide stratigraphy for the 1.5 m upper part (Thevenon et al., 2013). Magnetic susceptibility and density were measured by Geotek MultiSensor Core Logger at 0.5 cm resolution. Granulometry was measured with a CILAS grain sizer every 10 cm, and X-ray fluorescence (XRF) was carried out using an Avaatech core scanner at 1-cm resolution. This technique provides semi-quantitative information of the sediment elemental composition and shows how runoff and river input (Ti, Al, Si) or redox conditions (Fe/Mn) vary through time. Lake Biel sediment record suggests marked environmental changes with runoff decrease linked to climate and vegetation change during Atlantic chronobiozone, as well as a complex climate-human impact during the 'La Tène' and Roman cultural times. The most prominent recorded feature is the 10-times increase of sediment rate that occurred after the Aare river deviation through the Hagneck canal into Lake Biel in 1878. This artificial

  17. A NASA F/A-18, participating in the Automated Aerial Refueling (AAR) project, flies over the Dryden

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A NASA F/A-18 flies over the Dryden Flight Research Center and Rogers Dry Lake on December 11, 2002. The aircraft is participating in the Automated Aerial Refueling (AAR) project. The 300-gallon aerial refueling store seen on the belly of the aircraft carries fuel and a refueling drogue. This aircraft acts as a tanker in the study to develop an aerodynamic model for future automated aerial refueling, especially of unmanned vehicles.

  18. Farnesylation mediates brassinosteroid biosynthesis to regulate abscisic acid responses.

    PubMed

    Northey, Julian G B; Liang, Siyu; Jamshed, Muhammad; Deb, Srijani; Foo, Eloise; Reid, James B; McCourt, Peter; Samuel, Marcus A

    2016-01-01

    Protein farnesylation is a post-translational modification involving the addition of a 15-carbon farnesyl isoprenoid to the carboxy terminus of select proteins(1-3). Although the roles of this lipid modification are clear in both fungal and animal signalling, many of the mechanistic functions of farnesylation in plant signalling are still unknown. Here, we show that CYP85A2, the cytochrome P450 enzyme that performs the last step in brassinosteroid biosynthesis (conversion of castasterone to brassinolide)(4), must be farnesylated to function in Arabidopsis. Loss of either CYP85A2 or CYP85A2 farnesylation results in reduced brassinolide accumulation and increased plant responsiveness to the hormone abscisic acid (ABA) and overall drought tolerance, explaining previous observations(5). This result not only directly links farnesylation to brassinosteroid biosynthesis but also suggests new strategies to maintain crop yield under challenging climatic conditions. PMID:27455172

  19. Saturated fatty acids trigger TLR4-mediated inflammatory response.

    PubMed

    Rocha, D M; Caldas, A P; Oliveira, L L; Bressan, J; Hermsdorff, H H

    2016-01-01

    Toll-like receptors (TLR) mediate infection-induced inflammation and sterile inflammation by endogenous molecules. Among the TLR family, TLR4 is the best understood. However, while its downstream signaling pathways have been well defined, not all ligands of TLR4 are currently known. Current evidence suggests that saturated fatty acids (SFA) act as non-microbial TLR4 agonists, and trigger its inflammatory response. Thus, our present review provides a new perspective on the potential mechanism by which SFAs could modulate TLR4-induced inflammatory responses: (1) SFAs can be recognized by CD14-TLR4-MD2 complex and trigger inflammatory pathways, similar to lipopolysaccharide (LPS). (2) SFAs lead to modification of gut microbiota with an overproduction of LPS after a high-fat intake, enhancing this natural TLR4 ligand. (3) In addition, this metabolic endotoxemia leads to an oxidative stress thereby producing atherogenic lipids - oxLDL and oxidized phospholipids - which trigger CD36-TLR4-TLR6 inflammatory response. (4) Also, the high SFA consumption increases the lipemia and the mmLDL and oxLDL formation through oxidative modifications of LDL. The mmLDL, unlike oxLDL, is involved in activation of the CD14-TLR4-MD2 inflammatory pathway. Those molecules can induce TLR4 inflammatory response by MyD88-dependent and/or MyD88-independent pathways that, in turn, promotes the expression of proinflammatory transcript factors such as factor nuclear kappa B (NF-κB), which plays a crucial role in the induction of inflammatory mediators (cytokines, chemokines, or costimulatory molecules) implicated in the development and progression of many chronic diseases. PMID:26687466

  20. Transcriptome Sequencing in Response to Salicylic Acid in Salvia miltiorrhiza

    PubMed Central

    Zhang, Xiaoru; Dong, Juane; Liu, Hailong; Wang, Jiao; Qi, Yuexin; Liang, Zongsuo

    2016-01-01

    Salvia miltiorrhiza is a traditional Chinese herbal medicine, whose quality and yield are often affected by diseases and environmental stresses during its growing season. Salicylic acid (SA) plays a significant role in plants responding to biotic and abiotic stresses, but the involved regulatory factors and their signaling mechanisms are largely unknown. In order to identify the genes involved in SA signaling, the RNA sequencing (RNA-seq) strategy was employed to evaluate the transcriptional profiles in S. miltiorrhiza cell cultures. A total of 50,778 unigenes were assembled, in which 5,316 unigenes were differentially expressed among 0-, 2-, and 8-h SA induction. The up-regulated genes were mainly involved in stimulus response and multi-organism process. A core set of candidate novel genes coding SA signaling component proteins was identified. Many transcription factors (e.g., WRKY, bHLH and GRAS) and genes involved in hormone signal transduction were differentially expressed in response to SA induction. Detailed analysis revealed that genes associated with defense signaling, such as antioxidant system genes, cytochrome P450s and ATP-binding cassette transporters, were significantly overexpressed, which can be used as genetic tools to investigate disease resistance. Our transcriptome analysis will help understand SA signaling and its mechanism of defense systems in S. miltiorrhiza. PMID:26808150

  1. Transcriptome Sequencing in Response to Salicylic Acid in Salvia miltiorrhiza.

    PubMed

    Zhang, Xiaoru; Dong, Juane; Liu, Hailong; Wang, Jiao; Qi, Yuexin; Liang, Zongsuo

    2016-01-01

    Salvia miltiorrhiza is a traditional Chinese herbal medicine, whose quality and yield are often affected by diseases and environmental stresses during its growing season. Salicylic acid (SA) plays a significant role in plants responding to biotic and abiotic stresses, but the involved regulatory factors and their signaling mechanisms are largely unknown. In order to identify the genes involved in SA signaling, the RNA sequencing (RNA-seq) strategy was employed to evaluate the transcriptional profiles in S. miltiorrhiza cell cultures. A total of 50,778 unigenes were assembled, in which 5,316 unigenes were differentially expressed among 0-, 2-, and 8-h SA induction. The up-regulated genes were mainly involved in stimulus response and multi-organism process. A core set of candidate novel genes coding SA signaling component proteins was identified. Many transcription factors (e.g., WRKY, bHLH and GRAS) and genes involved in hormone signal transduction were differentially expressed in response to SA induction. Detailed analysis revealed that genes associated with defense signaling, such as antioxidant system genes, cytochrome P450s and ATP-binding cassette transporters, were significantly overexpressed, which can be used as genetic tools to investigate disease resistance. Our transcriptome analysis will help understand SA signaling and its mechanism of defense systems in S. miltiorrhiza. PMID:26808150

  2. Structural Evolution in the Aar Massif (Central Alps): First attempts of linking the micron- to the kilometer-scale

    NASA Astrophysics Data System (ADS)

    Wehrens, P.; Baumberger, R.; Herwegh, M.

    2012-04-01

    The Aar massif belongs to the external massifs of the Alps and is mainly composed of granitoids and gneisses. Despite numerous detailed studies in the past decades, the overall exhumation history and the associated massif internal deformation (internal strain distribution and its evolution in time, kinematics etc.) are largely unknown at present. In this project, we aim to investigate the role of shear zones in the deformation history at a variety of scales. In this context it is important to understand their microstructural evolution, the involved deformation processes, kinematics and relative ages as well as the associated changes in rheology. A GIS-based remote-sensing structural map, verified by fieldwork, (see Baumberger et al., this volume) served as base for our investigations. Lithological differences between the units (Central Aare granite, ZAGr; Grimsel granodiorte, GrGr and gneisses) cause strain to localize along these contacts. Furthermore, the initial magmatic differentiation in the granitoids locally controls the Alpine deformational overprint because of differences in effective viscosity during solid-state deformation. This behavior is illustrated by the increase of foliation intensity and the number of shear zones per rock volume from ZAGr to GrGr. Preliminary results show that deformation at the N boundary of the Aar massif has to be distinguished from the central and the southern part. In the North steep NE-SW trending foliations and shear zones with subvertical lineations represent the major structures. The shear zones acted both as normal faults and as reverse faults, which mostly used pre-existing lithological boundaries between the different gneiss units. In a later stage, E-W trending shear zones and shear bands with moderate dipping angles cross cut the earlier structures. They always show a top to the North component and might be related to the late north directed movements of the Aar massif. Yet, no absolute age dating has been performed

  3. Water Stress Responses of Tomato Mutants Impaired in Hormone Biosynthesis Reveal Abscisic Acid, Jasmonic Acid and Salicylic Acid Interactions.

    PubMed

    Muñoz-Espinoza, Valeria A; López-Climent, María F; Casaretto, José A; Gómez-Cadenas, Aurelio

    2015-01-01

    To investigate the putative crosstalk between JA and ABA in Solanum lycopersicum plants in response to drought, suppressor of prosystemin-mediated responses2 (spr2, JA-deficient) and flacca (flc, ABA-deficient) mutants together with the naphthalene/salicylate hydroxylase (NahG) transgenic (SA-deficient) line were used. Hormone profiling and gene expression of key enzymes in ABA, JA and SA biosynthesis were analyzed during early stages of drought. ABA accumulation was comparable in spr2 and wild type (WT) plants whereas expression of 9-cis-epoxycarotenoid dioxygenase 1 (NCED1) and NCED2 was different, implying a compensation mechanism between NCED genes and an organ-specific regulation of NCED1 expression. JA levels and 12-oxo-phytodienoic acid reductase 3 (OPR3) expression in flc plants suggest that ABA regulates the induction of the OPR3 gene in roots. By contrast, ABA treatment to flc plants leads to a reduction of JA and SA contents. Furthermore, different pattern of SA accumulation (and expression of isochorismate synthase and phenylalanine ammonia lyase 1) was observed between WT seedlings and mutants, suggesting that SA plays an important role on the early response of tomato plants to drought and also that JA and ABA modulate its biosynthesis. Finally, hormone profiling in spr2 and NahG plants indicate a crosstalk between JA and SA that could enhance tolerance of tomato to water stress. PMID:26635826

  4. Water Stress Responses of Tomato Mutants Impaired in Hormone Biosynthesis Reveal Abscisic Acid, Jasmonic Acid and Salicylic Acid Interactions

    PubMed Central

    Muñoz-Espinoza, Valeria A.; López-Climent, María F.; Casaretto, José A.; Gómez-Cadenas, Aurelio

    2015-01-01

    To investigate the putative crosstalk between JA and ABA in Solanum lycopersicum plants in response to drought, suppressor of prosystemin-mediated responses2 (spr2, JA-deficient) and flacca (flc, ABA-deficient) mutants together with the naphthalene/salicylate hydroxylase (NahG) transgenic (SA-deficient) line were used. Hormone profiling and gene expression of key enzymes in ABA, JA and SA biosynthesis were analyzed during early stages of drought. ABA accumulation was comparable in spr2 and wild type (WT) plants whereas expression of 9-cis-epoxycarotenoid dioxygenase 1 (NCED1) and NCED2 was different, implying a compensation mechanism between NCED genes and an organ-specific regulation of NCED1 expression. JA levels and 12-oxo-phytodienoic acid reductase 3 (OPR3) expression in flc plants suggest that ABA regulates the induction of the OPR3 gene in roots. By contrast, ABA treatment to flc plants leads to a reduction of JA and SA contents. Furthermore, different pattern of SA accumulation (and expression of isochorismate synthase and phenylalanine ammonia lyase 1) was observed between WT seedlings and mutants, suggesting that SA plays an important role on the early response of tomato plants to drought and also that JA and ABA modulate its biosynthesis. Finally, hormone profiling in spr2 and NahG plants indicate a crosstalk between JA and SA that could enhance tolerance of tomato to water stress. PMID:26635826

  5. Human Skeletal Muscle Protein Metabolism Responses to Amino Acid Nutrition.

    PubMed

    Mitchell, W Kyle; Wilkinson, Daniel J; Phillips, Bethan E; Lund, Jonathan N; Smith, Kenneth; Atherton, Philip J

    2016-07-01

    Healthy individuals maintain remarkably constant skeletal muscle mass across much of adult life, suggesting the existence of robust homeostatic mechanisms. Muscle exists in dynamic equilibrium whereby the influx of amino acids (AAs) and the resulting increases in muscle protein synthesis (MPS) associated with the intake of dietary proteins cancel out the efflux of AAs from muscle protein breakdown that occurs between meals. Dysregulated proteostasis is evident with aging, especially beyond the sixth decade of life. Women and men aged 75 y lose muscle mass at a rate of ∼0.7% and 1%/y, respectively (sarcopenia), and lose strength 2- to 5-fold faster (dynapenia) as muscle "quality" decreases. Factors contributing to the disruption of an otherwise robust proteostatic system represent targets for potential therapies that promote healthy aging. Understanding age-related impairments in anabolic responses to AAs and identifying strategies to mitigate these factors constitute major areas of interest. Numerous studies have aimed to identify 1) the influence of distinct protein sources on absorption kinetics and muscle anabolism, 2) the latency and time course of MPS responses to protein/AAs, 3) the impacts of protein/AA intake on muscle microvascular recruitment, and 4) the role of certain AAs (e.g., leucine) as signaling molecules, which are able to trigger anabolic pathways in tissues. This review aims to discuss these 4 issues listed, to provide historical and modern perspectives of AAs as modulators of human skeletal muscle protein metabolism, to describe how advances in stable isotope/mass spectrometric approaches and instrumentation have underpinned these advances, and to highlight relevant differences between young adults and older individuals. Whenever possible, observations are based on human studies, with additional consideration of relevant nonhuman studies. PMID:27422520

  6. White Bluffs Pickling Acid Cribs expedited response action proposal

    SciTech Connect

    Not Available

    1993-07-01

    The US Environmental Protection Agency (EPA) and Washington State Department of Ecology (Ecology) recommended in a letter dated March 4, 1992 (Attachment 1) that the US Department of Energy (DOE) prepare an expedited response action (ERA) for the White Bluffs Pickling Acid Cribs Site. The lead regulatory agency for this ERA is the EPA, with Ecology providing support. The goal of this ERA is to reduce the potential of any residual contaminant migration from the cribs to the soil column and groundwater. The cribs are the only waste site within the 100-IU-5 operable unit. Since the operable unit is surrounded by other waste units, tracing the potential groundwater contamination from the 100-IU-5 operable unit for this ERA would not be effective. Groundwater will be investigated with the 100-IU-2 operable unit. This ERA proposal presents the characterization data from the site investigations conducted in November of 1992. This information is evaluated to present the best method for reducing potential of contaminant migration from the disposal unit, ensuring both protection of human health and the environment. The ERA proposal will undergo a public review. EPA and Ecology will issue an Action Agreement Memorandum after comment resolution. This Action Memorandum may authorize implementation of the ERA proposal`s recommended alternative. The ERA may also provide a No Further Action Interim Record of Decision (IROD) of the 100-IU-5 operable unit.

  7. The Omega-3 Fatty Acid Eicosapentaenoic Acid Is Required for Normal Alcohol Response Behaviors in C. elegans

    PubMed Central

    Raabe, Richard C.; Mathies, Laura D.; Davies, Andrew G.; Bettinger, Jill C.

    2014-01-01

    Alcohol addiction is a widespread societal problem, for which there are few treatments. There are significant genetic and environmental influences on abuse liability, and understanding these factors will be important for the identification of susceptible individuals and the development of effective pharmacotherapies. In humans, the level of response to alcohol is strongly predictive of subsequent alcohol abuse. Level of response is a combination of counteracting responses to alcohol, the level of sensitivity to the drug and the degree to which tolerance develops during the drug exposure, called acute functional tolerance. We use the simple and well-characterized nervous system of Caenorhabditis elegans to model the acute behavioral effects of ethanol to identify genetic and environmental factors that influence level of response to ethanol. Given the strong molecular conservation between the neurobiological machinery of worms and humans, cellular-level effects of ethanol are likely to be conserved. Increasingly, variation in long-chain polyunsaturated fatty acid levels has been implicated in complex neurobiological phenotypes in humans, and we recently found that fatty acid levels modify ethanol responses in worms. Here, we report that 1) eicosapentaenoic acid, an omega-3 polyunsaturated fatty acid, is required for the development of acute functional tolerance, 2) dietary supplementation of eicosapentaenoic acid is sufficient for acute tolerance, and 3) dietary eicosapentaenoic acid can alter the wild-type response to ethanol. These results suggest that genetic variation influencing long-chain polyunsaturated fatty acid levels may be important abuse liability loci, and that dietary polyunsaturated fatty acids may be an important environmental modulator of the behavioral response to ethanol. PMID:25162400

  8. Response of soybean seed germination to cadmium and acid rain.

    PubMed

    Liu, Ting Ting; Wu, Peng; Wang, Li Hong; Zhou, Qing

    2011-12-01

    Cadmium (Cd) pollution and acid rain are the main environmental issues, and they often occur in the same agricultural region. Nevertheless, up to now, little information on the combined pollution of Cd(2+) and acid rain action on crops were presented. Here, we investigated the combined effect of Cd(2+) and acid rain on the seed germination of soybean. The results indicated that the single treatment with the low level of Cd(2+) (0.18, 1.0, 3.0 mg L(-1)) or acid rain (pH ≥3.0) could not affect the seed germination of soybean, which was resulted in the increased activities of peroxidase and catalase. The single treatment with the high concentration of Cd(2+) (>6 mg L(-1)) or acid rain at pH 2.5 decreased the activities of peroxidase and catalase, damaged the cell membrane and then decreased the seed germination of soybean. Meanwhile, the same toxic effect was observed in the combined treatment with Cd(2+) and acid rain, and the combined treatment had more toxic effect than the single treatment with Cd(2+) or acid rain. Thus, the combined pollution of Cd(2+) and acid rain had more potential threat to the seed germination of soybean than the single pollution of Cd(2+) or acid rain. PMID:21479540

  9. Delta 4-3-oxosteroid 5 beta-reductase deficiency: failure of ursodeoxycholic acid treatment and response to chenodeoxycholic acid plus cholic acid.

    PubMed Central

    Clayton, P T; Mills, K A; Johnson, A W; Barabino, A; Marazzi, M G

    1996-01-01

    BACKGROUND--In some infants with liver disease, 3-oxo-delta 4 bile acids are the major bile acids in urine, a phenomenon attributed to reduced activity of the delta 4-3-oxosteroid 5 beta-reductase required for synthesis of chenodeoxycholic acid and cholic acid. These patients form a heterogeneous group. Many have a known cause of hepatic dysfunction and plasma concentrations of chenodeoxycholic acid and cholic acid that are actually greater than those of the 3-oxo-delta 4 bile acids. It is unlikely that these patients have a primary genetic deficiency of the 5 beta-reductase enzyme. AIMS--To document the bile acid profile, clinical phenotype, and response to treatment of an infant with cholestasis, increased plasma concentrations of 3-oxo-delta 4 bile acids, low plasma concentrations of chenodeoxycholic acid and cholic acid, and no other identifiable cause of liver disease. PATIENTS--This infant was compared with normal infants and infants with cholestasis of known cause. METHODS--Analysis of bile acids by liquid secondary ionisation mass spectrometry and gas chromatography-mass spectrometry. RESULTS--The plasma bile acid profile of the patient was unique. She had chronic cholestatic liver disease associated with malabsorption of vitamins D and E and a normal gamma-glutamyltranspeptidase when the transaminases were increased. The liver disease failed to improve with ursodeoxycholic acid but responded to a combination of chenodeoxycholic acid and cholic acid. CONCLUSION--Treatment of primary 5 beta-reductase deficiency requires the use of bile acids that inhibit cholesterol 7 alpha-hydroxylase. PMID:8707100

  10. Octanoic acid in alcohol-responsive essential tremor

    PubMed Central

    McCrossin, Gayle; Lungu, Codrin; Considine, Elaine; Toro, Camilo; Nahab, Fatta B.; Auh, Sungyoung; Buchwald, Peter; Grimes, George J.; Starling, Judith; Potti, Gopal; Scheider, Linda; Kalowitz, Daniel; Bowen, Daniel; Carnie, Andrea; Hallett, Mark

    2013-01-01

    Objective: To assess safety and efficacy of an oral, single, low dose of octanoic acid (OA) in subjects with alcohol-responsive essential tremor (ET). Methods: We conducted a double-blind, placebo-controlled, crossover, phase I/II clinical trial evaluating the effect of 4 mg/kg OA in 19 subjects with ET. The primary outcome was accelerometric postural tremor power of the dominant hand 80 minutes after administration. Secondary outcomes included digital spiral analysis, pharmacokinetic sampling, as well as safety measures. Results: OA was safe and well tolerated. Nonserious adverse events were mild (Common Terminology Criteria for Adverse Events grade 1) and equally present after OA and placebo. At the primary outcome, OA effects were not different from placebo. Secondary outcome analyses of digital spiral analysis, comparison across the entire time course in weighted and nonweighted accelerometry, as well as nondominant hand tremor power did not show a benefit of OA over placebo. The analysis of individual time points showed that OA improved tremor at 300 minutes (dominant hand, F1,16 = 5.49, p = 0.032 vs placebo), with a maximum benefit at 180 minutes after OA (both hands, F1,16 = 6.1, p = 0.025). Conclusions: Although the effects of OA and placebo at the primary outcome were not different, secondary outcome measures suggest superiority of OA in reducing tremor at later time points, warranting further trials at higher dose levels. Classification of evidence: This study provides Class I evidence that a single 4-mg/kg dose of OA is not effective in reducing postural tremor in patients with ET at a primary outcome of 80 minutes, but is effective for a secondary outcome after 180 minutes. PMID:23408867

  11. Excellent amino acid racemization results from Holocene sand dollars

    NASA Astrophysics Data System (ADS)

    Kosnik, M.; Kaufman, D. S.; Kowalewski, M.; Whitacre, K.

    2015-12-01

    Amino acid racemization (AAR) is widely used as a cost-effective method to date molluscs in time-averaging and taphonomic studies, but it has not been attempted for echinoderms despite their paleobiological importance. Here we demonstrate the feasibility of AAR geochronology in Holocene aged Peronella peronii (Echinodermata: Echinoidea) collected from Sydney Harbour (Australia). Using standard HPLC methods we determined the extent of AAR in 74 Peronella tests and performed replicate analyses on 18 tests. We sampled multiple areas of two individuals and identified the outer edge as a good sampling location. Multiple replicate analyses from the outer edge of 18 tests spanning the observed range of D/Ls yielded median coefficients of variation < 4% for Asp, Phe, Ala, and Glu D/L values, which overlaps with the analytical precision. Correlations between D/L values across 155 HPLC injections sampled from 74 individuals are also very high (pearson r2 > 0.95) for these four amino acids. The ages of 11 individuals spanning the observed range of D/L values were determined using 14C analyses, and Bayesian model averaging was used to determine the best AAR age model. The averaged age model was mainly composed of time-dependent reaction kinetics models (TDK, 71%) based on phenylalanine (Phe, 94%). Modelled ages ranged from 14 to 5539 yrs, and the median 95% confidence interval for the 74 analysed individuals is ±28% of the modelled age. In comparison, the median 95% confidence interval for the 11 calibrated 14C ages was ±9% of the median age estimate. Overall Peronella yields exceptionally high-quality AAR D/L values and appears to be an excellent substrate for AAR geochronology. This work opens the way for time-averaging and taphonomic studies of echinoderms similar to those in molluscs.

  12. Development and validation of a predictive model for the influences of selected product and process variables on ascorbic acid degradation in simulated fruit juice.

    PubMed

    Gabriel, Alonzo A; Cayabyab, Jochelle Elysse C; Tan, Athalie Kaye L; Corook, Mark Lester F; Ables, Errol John O; Tiangson-Bayaga, Cecile Leah P

    2015-06-15

    A predictive response surface model for the influences of product (soluble solids and titratable acidity) and process (temperature and heating time) parameters on the degradation of ascorbic acid (AA) in heated simulated fruit juices (SFJs) was established. Physicochemical property ranges of freshly squeezed and processed juices, and a previously established decimal reduction times of Escherichiacoli O157:H7 at different heating temperatures were used in establishing a Central Composite Design of Experiment that determined the combinations of product and process variable used in the model building. Only the individual linear effects of temperature and heating time significantly (P<0.05) affected AA reduction (%AAr). Validating systems either over- or underestimated actual %AAr with bias factors 0.80-1.20. However, all validating systems still resulted in acceptable predictive efficacy, with accuracy factor 1.00-1.26. The model may be useful in establishing unique process schedules for specific products, for the simultaneous control and improvement of food safety and quality. PMID:25660889

  13. Conjugated Linoleic Acids and Inflammation: Isomer and Tissue Specific Responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conjugated linoleic acids (CLAs) are a series of geometric and positional isomers of linoleic acid that have been studied for their effects against diabetes, cancer, and atherosclerosis, all conditions with an inflammatory component. Despite the continued interest in CLA, there are many controversi...

  14. RESPONSE OF BUSH BEAN EXPOSED TO ACID MIST

    EPA Science Inventory

    Bush bean plants (Phaseolus vulgaris L. cv. Contender) were treated once a week for six weeks with simulated acid mist at five pH ranging from 5.5 to 2.0. Leaf injury developed on plants exposed to acid concentrations below pH 3 and many leaves developed a flecking symptom simila...

  15. Arabidopsis INCURVATA2 Regulates Salicylic Acid and Abscisic Acid Signaling, and Oxidative Stress Responses.

    PubMed

    Micol-Ponce, Rosa; Sánchez-García, Ana Belén; Xu, Qian; Barrero, José María; Micol, José Luis; Ponce, María Rosa

    2015-11-01

    Epigenetic regulatory states can persist through mitosis and meiosis, but the connection between chromatin structure and DNA replication remains unclear. Arabidopsis INCURVATA2 (ICU2) encodes the catalytic subunit of DNA polymerase α, and null alleles of ICU2 have an embryo-lethal phenotype. Analysis of icu2-1, a hypomorphic allele of ICU2, demonstrated that ICU2 functions in chromatin-mediated cellular memory; icu2-1 strongly impairs ICU2 function in the maintenance of repressive epigenetic marks but does not seem to affect ICU2 polymerase activity. To better understand the global function of ICU2 in epigenetic regulation, here we performed a microarray analysis of icu2-1 mutant plants. We found that the genes up-regulated in the icu2-1 mutant included genes encoding transcription factors and targets of the Polycomb Repressive Complexes. The down-regulated genes included many known players in salicylic acid (SA) biosynthesis and accumulation, ABA signaling and ABA-mediated responses. In addition, we found that icu2-1 plants had reduced SA levels in normal conditions; infection by Fusarium oxysporum induced SA accumulation in the En-2 wild type but not in the icu2-1 mutant. The icu2-1 plants were also hypersensitive to salt stress and exogenous ABA in seedling establishment, post-germination growth and stomatal closure, and accumulated more ABA than the wild type in response to salt stress. The icu2-1 mutant also showed high tolerance to the oxidative stress produced by 3-amino-1,2,4-triazole (3-AT). Our results uncover a role for ICU2 in the regulation of genes involved in ABA signaling as well as in SA biosynthesis and accumulation. PMID:26423959

  16. Physiological and transcriptional responses and cross protection of Lactobacillus plantarum ZDY2013 under acid stress.

    PubMed

    Huang, Renhui; Pan, Mingfang; Wan, Cuixiang; Shah, Nagendra P; Tao, Xueying; Wei, Hua

    2016-02-01

    Acid tolerance responses (ATR) in Lactobacillus plantarum ZDY2013 were investigated at physiological and molecular levels. A comparison of composition of cell membrane fatty acids (CMFA) between acid-challenged and unchallenged cells showed that acid adaptation evoked a significantly higher percentage of saturated fatty acids and cyclopropane fatty acids in acid-challenged than in unchallenged cells. In addition, reverse transcription-quantitative PCR analysis in acid-adapted cells at different pH values (ranging from 3.0 to 4.0) indicated that several genes were differently regulated, including those related to proton pumps, amino acid metabolism, sugar metabolism, and class I and class III stress response pathways. Expression of genes involved in fatty acid synthesis and production of alkali was significantly upregulated. Upon exposure to pH 4.5 for 2 h, a higher survival rate (higher viable cell count) of Lactobacillus plantarum ZDY2013 was achieved following an additional challenge to 40 mM hydrogen peroxide for 60 min, but no difference in survival rate of cells was found with further challenge to heat, ethanol, or salt. Therefore, we concluded that the physiological and metabolic changes of acid-treated cells of Lactobacillus plantarum ZDY2013 help the cells resist damage caused by acid, and further initiated global response signals to bring the whole cell into a state of defense to other stress factors, especially hydrogen peroxide. PMID:26627851

  17. Physiological and transcriptional response of Lactobacillus casei ATCC 334 to acid stress.

    PubMed

    Broadbent, Jeff R; Larsen, Rebecca L; Deibel, Virginia; Steele, James L

    2010-05-01

    This study investigated features of the acid tolerance response (ATR) in Lactobacillus casei ATCC 334. To optimize ATR induction, cells were acid adapted for 10 or 20 min at different pH values (range, 3.0 to 5.0) and then acid challenged at pH 2.0. Adaptation over a broad range of pHs improved acid tolerance, but the highest survival was noted in cells acid adapted for 10 or 20 min at pH 4.5. Analysis of cytoplasmic membrane fatty acids (CMFAs) in acid-adapted cells showed that they had significantly (P < 0.05) higher total percentages of saturated and cyclopropane fatty acids than did control cells. Specifically, large increases in the percentages of C(14:0), C(16:1n(9)), C(16:0), and C(19:0(11c)) were noted in the CMFAs of acid-adapted and acid-adapted, acid-challenged cells, while C(18:1n(9)) and C(18:1n(11)) showed the greatest decrease. Comparison of the transcriptome from control cells (grown at pH 6.0) against that from cells acid adapted for 20 min at pH 4.5 indicated that acid adaption invoked a stringent-type response that was accompanied by other functions which likely helped these cells resist acid damage, including malolactic fermentation and intracellular accumulation of His. Validation of microarray data was provided by experiments that showed that L. casei survival at pH 2.5 was improved at least 100-fold by chemical induction of the stringent response or by the addition of 30 mM malate or 30 mM histidine to the acid challenge medium. To our knowledge, this is the first report that intracellular histidine accumulation may be involved in bacterial acid resistance. PMID:20207759

  18. Physiological responses of Daphnia pulex to acid stress

    PubMed Central

    Weber, Anna K; Pirow, Ralph

    2009-01-01

    Background Acidity exerts a determining influence on the composition and diversity of freshwater faunas. While the physiological implications of freshwater acidification have been intensively studied in teleost fish and crayfish, much less is known about the acid-stress physiology of ecologically important groups such as cladoceran zooplankton. This study analyzed the extracellular acid-base state and CO2 partial pressure (PCO2), circulation and ventilation, as well as the respiration rate of Daphnia pulex acclimated to acidic (pH 5.5 and 6.0) and circumneutral (pH 7.8) conditions. Results D. pulex had a remarkably high extracellular pH of 8.33 and extracellular PCO2 of 0.56 kPa under normal ambient conditions (pH 7.8 and normocapnia). The hemolymph had a high bicarbonate concentration of 20.9 mM and a total buffer value of 51.5 meq L-1 pH-1. Bicarbonate covered 93% of the total buffer value. Acidic conditions induced a slight acidosis (ΔpH = 0.16–0.23), a 30–65% bicarbonate loss, and elevated systemic activities (tachycardia, hyperventilation, hypermetabolism). pH 6.0 animals partly compensated the bicarbonate loss by increasing the non-bicarbonate buffer value from 2.0 to 5.1 meq L-1 pH-1. The extracellular PCO2 of pH 5.5 animals was significantly reduced to 0.33 kPa, and these animals showed the highest tolerance to a short-term exposure to severe acid stress. Conclusion Chronic exposure to acidic conditions had a pervasive impact on Daphnia's physiology including acid-base balance, extracellular PCO2, circulation and ventilation, and energy metabolism. Compensatory changes in extracellular non-bicarbonate buffering capacity and the improved tolerance to severe acid stress indicated the activation of defense mechanisms which may result from gene-expression mediated adjustments in hemolymph buffer proteins and in epithelial properties. Mechanistic analyses of the interdependence between extracellular acid-base balance and CO2 transport raised the question of

  19. Electrogenic responses induced by neutral amino acids in endoderm cells from Xenopus embryo.

    PubMed Central

    Bergman, C; Bergman, J

    1981-01-01

    1. Membrane potential measurements were carried out on endoderm cells from early Xenopus embryos in order to study neutral amino acid transport in non-excitable cells. 2. The electrical properties of the cell membrane were studied under normal conditions, then in the presence of various Na/K-pump inhibitors and at different Na, K and Cl concentrations in Ringer solution. Blockade of the Na/K-pump by ouabain, Li, cooling to 10 degrees C or low [Na]0 induces similar depolarizations of about 40 mV. 3. External application of various neutral L-amino acids induces reversible membrane depolarizations. The D-isomeric forms are found to be ineffective. The amino acid induced depolarizations are not accompanied by changes in membrane resistance. They do not show voltage dependence for potential changes of less than 40 mV. 4. The amino acid depolarization increases with increasing concentration and follows first order Michaëlian kinetics. Both the size and the time course of the amino acid depolarization depend on [Na]0. Increasing [Na]0 markedly increases the apparent affinity of the membrane receptor for amino acid. 5. Increasing [k]0 reduces the size of the amino acid response. Short exposures to either ouabain or Li do not alter the amino acid depolarization. However, p time course of the amino acid depolarization depend on [Na]0. Increasing [Na]0 markedly increases the apparent affinity of the membrane receptor for amino acid. 5. Increasing [k]0 reduces the size of the amino acid response. Short exposures to either ouabain or Li do not alter the amino acid depolarization. However, p time course of the amino acid depolarization depend on [Na]0. Increasing [Na]0 markedly increases the apparent affinity of the membrane receptor for amino acid. 5. Increasing [k]0 reduces the size of the amino acid response. Short exposures to either ouabain or Li do not alter the amino acid depolarization. However, prolonged exposure to pump inhibitors or marked alteration of the Na

  20. A collaborative effort to model plant response to acidic rain

    SciTech Connect

    Jacobson, J.; Irving, P.; Kuja, A.; Lee, J.; Shriner, D.; Troiano, J.; Perrigan, S.; Cullinan, V.

    1989-01-01

    Radish plants were exposed three times per week to simulated acidic rain at pH values of 2.6 to 5.4 over the course of four weeks in trials performed at Argonne, Illinois; Ithaca and Upton, New York; Corvallis, Oregon; Oak Ridge, Tennessee; and Toronto, Canada. Uniform genotype, soil media and planting techniques, treatment procedures, biological measurements, and experimental design were employed. Growth of plants differed among trials as a result of variation in greenhouse environmental conditions according to location and facilities. Larger plants underwent greater absolute but lower relative reductions in biomass after exposure to the higher levels of acidity. A generalized Mitscherlich function was used to model the effects of acidity of simulated rain on dry mass of hypocotyls using data from three laboratories that performed duplicate trials. The remaining data, from three other laboratories that performed only one trial each, were used to test the model. 14 refs., 2 figs., 7 tabs.

  1. Plasma omega 3 polyunsaturated fatty acid status and monounsaturated fatty acids are altered by chronic social stress and predict endocrine responses to acute stress in titi monkeys

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Disturbances in fatty acid (FA) metabolism may link chronic psychological stress, endocrine responsiveness, and psychopathology. Therefore, lipid metabolome-wide responses and their relationships with endocrine (cortisol; insulin; adiponectin) responsiveness to acute stress (AS) were assessed in a ...

  2. COLLABORATIVE EFFORT TO MODEL PLANT RESPONSE TO ACIDIC RAIN

    EPA Science Inventory

    Radish plants were exposed three times per week to simulated acidic rain at pH values of 2.6 to 5.4 over the course of four weeks in trials performed at Argonne, IL; Ithaca & Upton, NY; Corvallis, OR; Oak Ridge, TN; and Toronto, Canada. niform genotype, soil media and planting te...

  3. DIETARY AMINO ACID RESPONSES OF BROILER CHICKENS: A REVIEW

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In commercial practice, formulating diets to adequate amino acid (AA) minimums is critical to optimize live production and meat yield of broiler chickens. The modern broiler has lower feed intake per unit BW gain while having the potential to accrete more white meat than the commercial broiler of p...

  4. Plasma oxylipin profiling identifies polyunsaturated vicinal diols as responsive to arachidonic acid and docosahexaenoic acid intake in growing piglets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dose-responsiveness of plasma oxylipins to incremental dietary intake of arachidonic (20:4n-6; ARA) and docosahexaenoic (22:6n-3; DHA) acid was determined in piglets. Piglets randomly received one of six formulas (n=8 per group) from day 3 to 27 postnatally. Diets contained varying ARA and DHA l...

  5. Microbial community potentially responsible for acid and metal release from an Ostrobothnian acid sulfate soil

    PubMed Central

    Wu, Xiaofen; Lim Wong, Zhen; Sten, Pekka; Engblom, Sten; Österholm, Peter; Dopson, Mark; Nakatsu, Cindy

    2013-01-01

    Soils containing an approximately equal mixture of metastable iron sulfides and pyrite occur in the boreal Ostrobothnian coastal region of Finland, termed ‘potential acid sulfate soil materials’. If the iron sulfides are exposed to air, oxidation reactions result in acid and metal release to the environment that can cause severe damage. Despite that acidophilic microorganisms catalyze acid and metal release from sulfide minerals, the microbiology of acid sulfate soil (ASS) materials has been neglected. The molecular phylogeny of a depth profile through the plough and oxidized ASS layers identified several known acidophilic microorganisms and environmental clones previously identified from acid- and metal-contaminated environments. In addition, several of the 16S rRNA gene sequences were more similar to sequences previously identified from cold environments. Leaching of the metastable iron sulfides and pyrite with an ASS microbial enrichment culture incubated at low pH accelerated metal release, suggesting microorganisms capable of catalyzing metal sulfide oxidation were present. The 16S rRNA gene analysis showed the presence of species similar to Acidocella sp. and other clones identified from acid mine environments. These data support that acid and metal release from ASSs was catalyzed by indigenous microorganisms adapted to low pH. PMID:23369102

  6. An Alternative Retinoic Acid-responsive Stra6 Promoter Regulated in Response to Retinol Deficiency*

    PubMed Central

    Laursen, Kristian B.; Kashyap, Vasundhra; Scandura, Joseph; Gudas, Lorraine J.

    2015-01-01

    Cellular uptake of vitamin A (retinol) is essential for many biological functions. The Stra6 protein binds the serum retinol-binding protein, RBP4, and acts in conjunction with the enzyme lecithin:retinol acyltransferase to facilitate retinol uptake in some cell types. We show that in embryonic stem (ES) cells and in some tissues, the Stra6 gene encodes two distinct mRNAs transcribed from two different promoters. Whereas both are all-trans-retinoic acid (RA)-responsive in ES cells, the downstream promoter contains a half-site RA response element (RARE) and drives an ∼13-fold, RA-associated increase in luciferase reporter activity. We employed CRISPR-Cas9 genome editing to show that the endogenous RARE is required for RA-induced transcription of both Stra6 isoforms. We further demonstrate that in ES cells, 1) both RARγ and RXRα are present at the Stra6 RARE; 2) RA increases co-activator p300 (KAT3B) binding and histone H3 Lys-27 acetylation at both promoters; 3) RA decreases Suz12 levels and histone H3 Lys-27 trimethylation epigenetic marks at both promoters; and 4) these epigenetic changes are diminished in the absence of RARγ. In the brains of WT mice, both the longer and the shorter Stra6 transcript (Stra6L and Stra6S, respectively) are highly expressed, whereas these transcripts are found only at low levels in RARγ−/− mice. In the brains of vitamin A-deficient mice, both Stra6L and Stra6S levels are decreased. In contrast, in the vitamin A-deficient kidneys, the Stra6L levels are greatly increased, whereas Stra6S levels are decreased. Our data show that kidneys respond to retinol deficiency by differential Stra6 promoter usage, which may play a role in the retention of retinol when vitamin A is low. PMID:25544292

  7. An alternative retinoic acid-responsive Stra6 promoter regulated in response to retinol deficiency.

    PubMed

    Laursen, Kristian B; Kashyap, Vasundhra; Scandura, Joseph; Gudas, Lorraine J

    2015-02-13

    Cellular uptake of vitamin A (retinol) is essential for many biological functions. The Stra6 protein binds the serum retinol-binding protein, RBP4, and acts in conjunction with the enzyme lecithin:retinol acyltransferase to facilitate retinol uptake in some cell types. We show that in embryonic stem (ES) cells and in some tissues, the Stra6 gene encodes two distinct mRNAs transcribed from two different promoters. Whereas both are all-trans-retinoic acid (RA)-responsive in ES cells, the downstream promoter contains a half-site RA response element (RARE) and drives an ∼ 13-fold, RA-associated increase in luciferase reporter activity. We employed CRISPR-Cas9 genome editing to show that the endogenous RARE is required for RA-induced transcription of both Stra6 isoforms. We further demonstrate that in ES cells, 1) both RARγ and RXRα are present at the Stra6 RARE; 2) RA increases co-activator p300 (KAT3B) binding and histone H3 Lys-27 acetylation at both promoters; 3) RA decreases Suz12 levels and histone H3 Lys-27 trimethylation epigenetic marks at both promoters; and 4) these epigenetic changes are diminished in the absence of RARγ. In the brains of WT mice, both the longer and the shorter Stra6 transcript (Stra6L and Stra6S, respectively) are highly expressed, whereas these transcripts are found only at low levels in RARγ(-/-) mice. In the brains of vitamin A-deficient mice, both Stra6L and Stra6S levels are decreased. In contrast, in the vitamin A-deficient kidneys, the Stra6L levels are greatly increased, whereas Stra6S levels are decreased. Our data show that kidneys respond to retinol deficiency by differential Stra6 promoter usage, which may play a role in the retention of retinol when vitamin A is low. PMID:25544292

  8. The disturbance of small RNA pathways enhanced abscisic acid response and multiple stress responses in Arabidopsis.

    PubMed

    Zhang, Jian-Feng; Yuan, Li-Jie; Shao, Yi; Du, Wei; Yan, Da-Wei; Lu, Ying-Tang

    2008-04-01

    The phytohormone abscisic acid (ABA) regulates plant growth and development as well as stress tolerance. To gain more insights into ABA signalling, a population of chemical-inducible activation-tagged Arabidopsis mutants was screened on the basis of the ABA effect on the inhibition of seed germination. Two novel ABA supersensitive mutants ABA supersensitive during germination1 (absg1) and absg2 were characterized as alleles of Dicer-like1 (DCL1) and HEN1, respectively, as microRNA biogenesis genes, and accordingly, these two mutants were renamed dcl1-11 and hen1-16. The dcl1-11 mutant was an ABA hypersensitive mutant for seed germination and root growth. Reverse transcriptase polymerase chain reaction assays revealed that the expression of ABA- and stress-responsive genes was increased in dcl1-11, as compared with the wild type (WT). Furthermore, the germination assay showed that dcl1-11 was also more sensitive to salt and osmotic stress. The hen1-16 mutant also showed supersensitive to ABA during seed germination. Further analysis showed that, among the microRNA biogenesis genes, all the other mutants were not only enhanced in sensitivity to ABA, salt and osmotic stress, but also enhanced the expression of ABA-responsive genes. In addition to the mutants in the microRNA biogenesis, the interruption of the production of crucial components of other small RNA pathways such as dcl2, dcl3 and dcl4 also caused ABA supersensitive during germination. PMID:18208512

  9. PROJECTION OF RESPONSE OF TREES AND FORESTS TO ACIDIC DEPOSITION AND ASSOCIATED POLLUTANTS

    EPA Science Inventory

    In 1986 the National, Acid Precipitation Assessment Program (NAPAP) established the Forest Response Program (FRP) to assess the effects of acidic deposition and associated pollutants on forests. Modeling studies were developed in parallel with both field studies on the pattern an...

  10. 5-Aminolevulinic acid regulates the inflammatory response and alloimmune reaction.

    PubMed

    Fujino, Masayuki; Nishio, Yoshiaki; Ito, Hidenori; Tanaka, Tohru; Li, Xiao-Kang

    2016-08-01

    5-Aminolevulinic acid (5-ALA) is a naturally occurring amino acid and precursor of heme and protoporphyrin IX (PpIX). Exogenously administrated 5-ALA increases the accumulation of PpIX in tumor cells specifically due to the compromised metabolism of 5-ALA to heme in mitochondria. PpIX emits red fluorescence by the irradiation of blue light and the formation of reactive oxygen species and singlet oxygen. Thus, performing a photodynamic diagnosis (PDD) and photodynamic therapy (PDT) using 5-ALA have given rise to a new strategy for tumor diagnosis and therapy. In addition to the field of tumor therapy, 5-ALA has been implicated in the treatment of inflammatory disease, autoimmune disease and transplantation due to the anti-inflammation and immunoregulation properties that are elicited with the expression of heme oxygenase (HO)-1, an inducible enzyme that catalyzes the rate-limiting step in the oxidative degradation of heme to free iron, biliverdin and carbon monoxide (CO), in combination with sodium ferrous citrate (SFC), because an inhibitor of HO-1 abolishes the effects of 5-ALA. Furthermore, NF-E2-related factor 2 (Nrf2), mitogen-activated protein kinase (MAPK), and heme are involved in the HO-1 expression. Biliverdin and CO are also known to have anti-apoptotic, anti-inflammatory and immunoregulatory functions. We herein review the current use of 5-ALA in inflammatory diseases, transplantation medicine, and tumor therapy. PMID:26643355

  11. Amino acid racemization on planktic foraminifera from the central Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Hanslik, D.; Kaufman, D. S.; Jakobsson, M.

    2009-12-01

    Amino acid racemization (AAR) is the interconversion of amino acids from one chiral form (L - levo) to a mixture of L- and D- (dextro) forms as a function of time and temperature. The extent of AAR in foraminifera shells can be determined by measuring the ratio of D/L amino acids, and can be used as a relative dating method. The technique can also be used to determine numerical ages once the rate of racemization is calibrated for a study area using samples of known ages. In this study sediment cores from the Lomonosov Ridge (88°N) and Morris Jesup Rise (85°N), in the central Arctic Ocean, were analyzed for AAR on monospecific samples of the polar planktic foraminifera Neogloboquadrina pachyderma sinistral. Numerical ages were derived using an equation developed for aspartic and glutamic acids in a previous study on other cores from the Northwind, Mendeleev and Lomonosov ridges, which applies to samples younger than about 150 ka (Kaufman et al., 2008, Paleoceanography 23:PA3224). The calculated AAR ages are in relatively good agreement with 14C ages throughout the range of 14C dating for both of our cores. The core from Morris Jesup Rise includes older sediment beyond the range of 14C dating where ages were inferred from benthic foraminifera events and correlation with other cores with previously published age models. The AAR age for the level of unique occurrence of the benthic foramifera Bulimina aculeata from this core is about 85 ka, which agrees with previous work that assigned this level to MIS 5.1. Beyond about 85 ka, there is a progressively increasing age discrepancy between calculated AAR ages and estimated ages based on benthic foraminifera events. For MIS 5.5, the D/L values for the Epistominella exigua marker are lower in our core than in the cores analyzed by Kaufman et al. (2008). Assuming that this event is a chronostratigraphic marker, then the AAR results suggest that deepwater temperature at our site during MIS 5 was lower than at the other

  12. Production of Cell Wall Hydrolyzing Enzymes by Barley Aleurone Layers in Response to Gibberellic Acid 1

    PubMed Central

    Taiz, Lincoln; Honigman, William A.

    1976-01-01

    The cell walls of barley (Hordeum vulgare var. Himalaya) aleurone layers undergo extensive degradation during the tissue's response to gibberellic acid. Previous work had shown that these cell walls consist almost entirely of arabinoxylan. In this study we show that gibberellic acid stimulates endo-β-1,4-xylanase activity in isolated aleurone layers. In addition, gibberellic acid enhances the activity of two glycosidases: β-xylopyranosidase and α-arabinofuranosidase. No gibberellic acid-stimulated cellulase activity was detected. Germination studies showed a similar pattern of enzyme development in intact seeds. Images PMID:16659683

  13. Behavioral responses of western corn rootworm larvae to naturally occurring and synthetic hydroxamic acids.

    PubMed

    Xie, Y; Arnason, J T; Philogéne, B J; Atkinson, J; Morand, P

    1992-07-01

    Hydroxamic acids have been shown to be toxic to many pest insects and pathogens. In this study, the behavioral responses of western corn rootworm larvae to naturally occurring and synthetic hydroxamic acids were investigated. In a choice test between corn roots treated with hydroxamic acids and roots treated with distilled water (control), western corn rootworm larvae chose to burrow into the control roots significantly more often than compoundtreated roots. In addition, when corn roots were treated with different hydroxamic acids in a designed searching-behavior test, neonate larvae of western corn rootworm responded by significantly reducing the number of turns, while the area searched and locomotor rate significantly increased. The responses were dependent on the concentrations of the test compounds. These results suggested that hydroxamic acids were acting as behavior-modifying and possibly feeding-deterrent chemicals. PMID:24254140

  14. Mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M) is a pro-survival, endoplasmic reticulum (ER) stress response gene involved in tumor cell adaptation to nutrient availability.

    PubMed

    Méndez-Lucas, Andrés; Hyroššová, Petra; Novellasdemunt, Laura; Viñals, Francesc; Perales, Jose C

    2014-08-01

    Mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M), encoded by the nuclear PCK2 gene, links TCA cycle intermediates and glycolytic pools through the conversion of mitochondrial oxaloacetate into phosphoenolpyruvate. In the liver PEPCK-M adjoins its profusely studied cytosolic isoform (PEPCK-C) potentiating gluconeogenesis and TCA flux. However, PEPCK-M is present in a variety of non-gluconeogenic tissues, including tumors of several origins. Despite its potential relevance to cancer metabolism, the mechanisms responsible for PCK2 gene regulation have not been elucidated. The present study demonstrates PEPCK-M overexpression in tumorigenic cells as well as the mechanism for the modulation of PCK2 abundance under several stress conditions. Amino acid limitation and ER stress inducers, conditions that activate the amino acid response (AAR) and the unfolded protein response (UPR), stimulate PCK2 gene transcription. Both the AAR and UPR lead to increased synthesis of ATF4, which mediates PCK2 transcriptional up-regulation through its binding to a putative ATF/CRE composite site within the PCK2 promoter functioning as an amino acid response element. In addition, activation of the GCN2-eIF2α-ATF4 and PERK-eIF2α-ATF4 signaling pathways are responsible for increased PEPCK-M levels. Finally, PEPCK-M knockdown using either siRNA or shRNA were sufficient to reduce MCF7 mammary carcinoma cell growth and increase cell death under glutamine deprivation or ER stress conditions. Our data demonstrate that this enzyme has a critical role in the survival program initiated upon stress and shed light on an unexpected and important role of mitochondrial PEPCK in cancer metabolism. PMID:24973213

  15. Antifungal Activity and Biochemical Response of Cuminic Acid against Phytophthora capsici Leonian.

    PubMed

    Wang, Yong; Sun, Yang; Zhang, Ying; Zhang, Xing; Feng, Juntao

    2016-01-01

    Phytophthora blight of pepper caused by Phytophthora capsici Leonian is a destructive disease throughout the world. Cuminic acid, extracted from the seed of Cuminum cyminum L., belongs to the benzoic acid chemical class. In this study, the sensitivity and biochemical response of P. capsici to cuminic acid was determined. The mean EC50 (50% effective concentration) values for cuminic acid in inhibiting mycelial growth and zoospore germination of the 54 studied P. capsici isolates were 14.54 ± 5.23 μg/mL and 6.97 ± 2.82 μg/mL, respectively. After treatment with cuminic acid, mycelial morphology, sporangium formation and mycelial respiration were significantly influenced; cell membrane permeability and DNA content increased markedly, but pyruvic acid content, adenosine triphosphate (ATP) content, and ATPase activity decreased compared with the untreated control. In pot experiments, cuminic acid exhibited both protective and curative activity. Importantly, POD and PAL activity of the pepper leaves increased after being treated with cuminic acid. These indicated that cuminic acid not only showed antifungal activity, but also could improve the defense capacity of the plants. All the results suggested that cuminic acid exhibits the potential to be developed as a new phytochemical fungicide, and this information increases our understanding of the mechanism of action of cuminic acid against Phytophthora capsici. PMID:27294911

  16. Mucus glycoprotein secretion by duodenal mucosa in response to luminal arachidonic acid.

    PubMed

    Kosmala, M; Carter, S R; Konturek, S J; Slomiany, A; Slomiany, B L

    1986-12-10

    The effect of luminal application of arachidonic acid on the alkaline secretion, prostaglandin generation, and mucus glycoprotein output and composition was studied in proximal and distal duodenum of conscious dogs. Surgically prepared duodenal loops were instilled in vivo for up to 2 h with saline (control) followed by various concentrations (12.5-100 micrograms/ml) of arachidonic acid. The experiments were conducted with and without intravenous pretreatment with indomethacin. The recovered instillates were assayed for the content of prostaglandin and HCO3-, and used for the isolation of mucus glycoprotein. Exposure of duodenal mucosa to arachidonic acid led to concentration-dependent increase in the output of HCO3- and prostaglandin generation. In both cases this response was greater in the proximal duodenum. Pretreatment with indomethacin caused reduction in the basal HCO3- and prostaglandin output, and prevented the increments evoked by arachidonic acid. The proximal and distal duodenum displayed similar basal output and composition of mucus glycoprotein. Comparable increases in these glycoproteins were also obtained with arachidonic acid, the effect of which was abolished by indomethacin. Compared to basal conditions, mucus glycoproteins elaborated in response to arachidonic acid exhibited higher contents of associated lipids and covalently bound fatty acids, and contained less protein. The associated lipids of mucus glycoproteins elaborated in the presence of arachidonic acid showed enrichment in phospholipids and decrease in neutral lipids. The carbohydrate components in these glycoproteins also exhibited higher proportions of sialic acid and sulfate. The changes brought about by arachidonic acid were prevented by indomethacin pretreatment, and in both cases the glycoprotein composition returned to that obtained under basal conditions. The enrichment of mucus glycoprotein in lipids, sialic acid and sulfate in response to endogenous prostaglandin may be of

  17. [Association of fatty acid metabolism with systemic inflammatory response in chronic respiratory diseases].

    PubMed

    Denisenko, Y K; Novgorodtseva, T P; Zhukova, N V; Antonuk, M V; Lobanova, E G; Kalinina, E P

    2016-03-01

    We examined composition of plasma non-esterified fatty acids (NFAs), erythrocyte fatty acids, levels of eicosanoids in patients with asthma and chronic obstructive pulmonary disease (COPD) with different type of the inflammatory response. The results of our study show that asthma and COPD in remission are associated with changes in the composition NFAs of plasma, FA of erythrocytes, level eicosanoid despite the difference in the regulation of immunological mechanisms of systemic inflammation. These changes are characterized by excessive production of arachidonic acid (20:4n-6) and cyclooxygenase and lipoxygenase metabolites (thromboxane B2, leukotriene B4) and deficiency of their functional antagonist, eicosapentaenoic acid (20:5n-3). The recognized association between altered fatty acid composition and disorders of the immune mechanisms of regulation of systemic inflammation in COPD and asthma demonstrated the important role of fatty acids and their metabolites in persistence of inflammatory processes in diseases of the respiratory system in the condition of remission. PMID:27420629

  18. Regulation of intestinal IgA responses by dietary palmitic acid and its metabolism.

    PubMed

    Kunisawa, Jun; Hashimoto, Eri; Inoue, Asuka; Nagasawa, Risa; Suzuki, Yuji; Ishikawa, Izumi; Shikata, Shiori; Arita, Makoto; Aoki, Junken; Kiyono, Hiroshi

    2014-08-15

    Enhancement of intestinal IgA responses is a primary strategy in the development of oral vaccine. Dietary fatty acids are known to regulate host immune responses. In this study, we show that dietary palmitic acid (PA) and its metabolites enhance intestinal IgA responses. Intestinal IgA production was increased in mice maintained on a PA-enriched diet. These mice also showed increased intestinal IgA responses against orally immunized Ag, without any effect on serum Ab responses. We found that PA directly stimulates plasma cells to produce Ab. In addition, mice receiving a PA-enriched diet had increased numbers of IgA-producing plasma cells in the large intestine; this effect was abolished when serine palmitoyltransferase was inhibited. These findings suggest that dietary PA regulates intestinal IgA responses and has the potential to be a diet-derived mucosal adjuvant. PMID:25031459

  19. Taste responses to binary mixtures of amino acids in the sea catfish, Arius felis.

    PubMed

    Kohbara, J; Caprio, J

    1996-02-01

    In vivo electrophysiological recordings in the sea catfish, Arius felis, showed that the magnitude of the integrated facial taste responses to binary mixtures of amino acids was predictable with knowledge obtained from previous cross-adaptation studies of the relative independence of the respective binding sites of the component stimuli. Each component from which equal aliquots were drawn to form the mixtures was adjusted in concentration to provide for approximately equal response magnitudes. The magnitude of the taste responses to binary mixtures whose component amino acids showed minimal cross-adaptation was significantly greater than that to binary mixtures whose components exhibited considerable cross-reactivity. There was no evidence for mixture suppression. The relative magnitude of the taste responses in the sea catfish to stimulus mixtures is similar to that previously reported for olfactory receptor responses in the freshwater channel catfish and chorda tympani taste responses in the hamster. PMID:8646491

  20. Role of ω-hydroxylase in adenosine-mediated aortic response through MAP kinase using A2A-receptor knockout mice.

    PubMed

    Ponnoth, Dovenia S; Nayeem, Mohammed A; Kunduri, Swati S; Tilley, Stephen L; Zeldin, Darryl C; Ledent, Catherine; Mustafa, S Jamal

    2012-02-15

    Previously, we have shown that A(2A) adenosine receptor (A(2A)AR) knockout mice (KO) have increased contraction to adenosine. The signaling mechanism(s) for A(2A)AR is still not fully understood. In this study, we hypothesize that, in the absence of A(2A)AR, ω-hydroxylase (Cyp4a) induces vasoconstriction through mitogen-activated protein kinase (MAPK) via upregulation of adenosine A(1) receptor (A(1)AR) and protein kinase C (PKC). Organ bath and Western blot experiments were done using isolated aorta from A(2A)KO and corresponding wild-type (WT) mice. Isolated aortic rings from WT and A(2A)KO mice were precontracted with submaximal dose of phenylephrine (10(-6) M), and concentration responses for selective A(1)AR, A(2A)AR agonists, angiotensin II and cytochrome P-450-epoxygenase, 20-hydroxyeicosatrienoic acid (20-HETE) PKC, PKC-α, and ERK1/2 inhibitors were obtained. 2-p-(2-Carboxyethyl)-phenethylamino-5'-N-ethylcarboxamidoadenosine hydrochloride (CGS-21680, A(2A)AR agonist) induced concentration-dependent relaxation in WT, which was blocked by methylsulfonyl-propargyloxyphenylhexanamide (cytochrome P-450-epoxygenase inhibitor; 10(-5) M) and also with removal of endothelium. A(1) agonist, 2-chloro-N(6)-cyclopentyladenosine (CCPA) produced higher contraction in A(2A)KO aorta than WT (49.2 ± 8.5 vs. 27 ± 5.9% at 10(-6) M, P < 0.05). 20-HETE produced higher contraction in A(2A)KO than WT (50.6 ± 8.8 vs. 21.1 ± 3.3% at 10(-7) M, P < 0.05). Contraction to CCPA in WT and A(2A)KO aorta was inhibited by PD-98059 (p42/p44 MAPK inhibitor; 10(-6) M), chelerythrine chloride (nonselective PKC blocker; 10(-6) M), Gö-6976 (selective PKC-α inhibitor; 10(-7) M), and HET0016 (20-HETE inhibitor; 10(-5) M). Also, contraction to 20-HETE in WT and A(2A)KO aorta was inhibited by PD-98059 and Gö-6976. Western blot analysis indicated the upregulation of A(1)AR, Cyp4a, PKC-α, and phosphorylated-ERK1/2 in A(2A)KO compared with WT (P < 0.05), while expression of Cyp2c29 was

  1. In vitro release of arachidonic acid and in vivo responses to respirable fractions of cotton dust

    SciTech Connect

    Thomson, T.A.; Edwards, J.H.; Al-Zubaidy, T.S.; Brown, R.C.; Poole, A.; Nicholls, P.J.

    1986-04-01

    It was considered that the fall in lung function seen after exposure to cotton dust may be attributable in part to the activity of arachidonic acid metabolites, such as leucotrienes as well as to the more established release of histamine by cotton dust. However, we found that cotton and barley dusts elicited poor release of arachidonic acid from an established macrophage like cell line compared with that observed with other organic dusts. In the experimental animal, pulmonary cellular responses to both cotton and barley dust were similar to those evoked by moldy hay and pigeon dropping dusts, although after multiple doses a more severe response was seen to cotton and barley. Since both moldy hay and pigeon droppings elicit a greater arachidonic acid release than cotton or barley, a role for arachidonic acid in inducing the cellular response is less likely than other factors. There are limitations to our conclusions using this system, i.e., the arachidonic acid may be released in a nonmetabolized form, although it is noted that the two dusts with the greatest arachidonic acid release produce their clinical responses in humans largely by hypersensitivity mechanisms.

  2. Photosynthetic and growth responses of Schima superba seedlings to sulfuric and nitric acid depositions.

    PubMed

    Yao, Fang-Fang; Ding, Hui-Ming; Feng, Li-Li; Chen, Jing-Jing; Yang, Song-Yu; Wang, Xi-Hua

    2016-05-01

    A continuing rise in acid deposition can cause forest degradation. In China, acid deposition has converted gradually from sulfuric acid deposition (SAD) to nitric acid deposition (NAD). However, the differing responses of photosynthesis and growth to depositions of sulfuric vs. nitric acid have not been well studied. In this study, 1-year-old seedlings of Schima superba, a dominant species in subtropical forests, were treated with two types of acid deposition SO4 (2-)/NO3 (-) ratios (8:1 and 0.7:1) with two applications (foliar spraying and soil drenching) at two pH levels (pH 3.5 and pH 2.5) over a period of 18 months. The results showed that the intensity, acid deposition type, and spraying method had significant effects on the physiological characteristics and growth performance of seedlings. Acid deposition at pH 2.5 via foliar application reduced photosynthesis and growth of S. superba, especially in the first year. Unlike SAD, NAD with high acidity potentially alleviated the negative effects of acidity on physiological properties and growth, probably due to a fertilization effect that improved foliar nitrogen and chlorophyll contents. Our results suggest that trees were damaged mainly by direct acid stress in the short term, whereas in the long term, soil acidification was also likely to be a major risk to forest ecosystems. Our data suggest that the shift in acid deposition type may complicate the ongoing challenge of anthropogenic acid deposition to ecosystem stability. PMID:26797956

  3. Low oleic acid-derived repression of jasmonic acid-inducible defense responses requires the WRKY50 and WRKY51 proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Signaling induced upon a reduction in oleic acid (18:1) levels simultaneously up-regulates salicylic acid (SA)-mediated responses and inhibits jasmonic acid (JA)-inducible defenses, resulting in enhanced resistance to biotrophs but increased susceptibility to necrotrophs. SA and the signaling compon...

  4. Plasma oxylipin profiling identifies polyunsaturated vicinal diols as responsive to arachidonic acid and docosahexaenoic acid intake in growing piglets.

    PubMed

    Bruins, Maaike J; Dane, Adrie D; Strassburg, Katrin; Vreeken, Rob J; Newman, John W; Salem, Norman; Tyburczy, Cynthia; Brenna, J Thomas

    2013-06-01

    The dose-responsiveness of plasma oxylipins to incremental dietary intake of arachidonic acid (20:4n-6; ARA) and docosahexaenoic acid (22:6n-3; DHA) was determined in piglets. Piglets randomly received one of six formulas (n = 8 per group) from days 3 to 27 postnatally. Diets contained incremental ARA or incremental DHA levels as follows (% fatty acid, ARA/DHA): (A1) 0.1/1.0; (A2) 0.53/1.0; (A3-D3) 0.69/1.0; (A4) 1.1/1.0; (D1) 0.66/0.33; and (D2) 0.67/0.62, resulting in incremental intake (g/kg BW/day) of ARA: 0.07 ± 0.01, 0.43 ± 0.03, 0.55 ± 0.03, and 0.82 ± 0.05 at constant DHA intake (0.82 ± 0.05), or incremental intake of DHA: 0.27 ± 0.02, 0.49 ± 0.03, and 0.81 ± 0.05 at constant ARA intake (0.54 ± 0.04). Plasma oxylipin concentrations and free plasma PUFA levels were determined at day 28 using LC-MS/MS. Incremental dietary ARA intake dose-dependently increased plasma ARA levels. In parallel, ARA intake dose-dependently increased ARA-derived diols 5,6- and 14,15-dihydroxyeicosatrienoic acid (DiHETrE) and linoleic acid-derived 12,13-dihydroxyoctadecenoic acid (DiHOME), downstream metabolites of cytochrome P450 expoxygenase (CYP). The ARA epoxide products from CYP are important in vascular homeostatic maintenance. Incremental DHA intake increased plasma DHA and most markedly raised the eicosapentaenoic acid (EPA) metabolite 17,18-dihydroxyeicosatetraenoic acid (DiHETE) and the DHA metabolite 19,20-dihydroxydocosapentaenoic acid (DiHDPE). In conclusion, increasing ARA and DHA intake dose-dependently influenced endogenous n-6 and n-3 oxylipin plasma concentrations in growing piglets, although the biological relevance of these findings remains to be determined. PMID:23543770

  5. Long-Term Effects of Acid Rain: Response and Recovery of a Forest Ecosystem

    NASA Astrophysics Data System (ADS)

    Likens, G. E.; Driscoll, C. T.; Buso, D. C.

    1996-04-01

    Long-term data from the Hubbard Brook Experimental Forest, New Hampshire, suggest that although changes in stream pH have been relatively small, large quantities of calcium and magnesium have been lost from the soil complex and exported by drainage water because of inputs of acid rain and declines in atmospheric deposition of base cations. As a result, the recovery of soil and streamwater chemistry in response to any decreases in acid deposition will be delayed significantly.

  6. Autotoxicity mechanism of Oryza sativa: transcriptome response in rice roots exposed to ferulic acid

    PubMed Central

    2013-01-01

    Background Autotoxicity plays an important role in regulating crop yield and quality. To help characterize the autotoxicity mechanism of rice, we performed a large-scale, transcriptomic analysis of the rice root response to ferulic acid, an autotoxin from rice straw. Results Root growth rate was decreased and reactive oxygen species, calcium content and lipoxygenase activity were increased with increasing ferulic acid concentration in roots. Transcriptome analysis revealed more transcripts responsive to short ferulic-acid exposure (1- and 3-h treatments, 1,204 genes) than long exposure (24 h, 176 genes). Induced genes were involved in cell wall formation, chemical detoxification, secondary metabolism, signal transduction, and abiotic stress response. Genes associated with signaling and biosynthesis for ethylene and jasmonic acid were upregulated with ferulic acid. Ferulic acid upregulated ATP-binding cassette and amino acid/auxin permease transporters as well as genes encoding signaling components such as leucine-rich repeat VIII and receptor-like cytoplasmic kinases VII protein kinases, APETALA2/ethylene response factor, WRKY, MYB and Zinc-finger protein expressed in inflorescence meristem transcription factors. Conclusions The results of a transcriptome analysis suggest the molecular mechanisms of plants in response to FA, including toxicity, detoxicification and signaling machinery. FA may have a significant effect on inhibiting rice root elongation through modulating ET and JA hormone homeostasis. FA-induced gene expression of AAAP transporters may contribute to detoxicification of the autotoxin. Moreover, the WRKY and Myb TFs and LRR-VIII and SD-2b kinases might regulate downstream genes under FA stress but not general allelochemical stress. This comprehensive description of gene expression information could greatly facilitate our understanding of the mechanisms of autotoxicity in plants. PMID:23705659

  7. Individual Variation in Lipidomic Profiles of Healthy Subjects in Response to Omega-3 Fatty Acids

    PubMed Central

    Nording, Malin L.; Yang, Jun; Georgi, Katrin; Hegedus Karbowski, Christine; German, J. Bruce; Weiss, Robert H.; Hogg, Ronald J.; Trygg, Johan; Hammock, Bruce D.; Zivkovic, Angela M.

    2013-01-01

    Introduction Conflicting findings in both interventional and observational studies have resulted in a lack of consensus on the benefits of ω3 fatty acids in reducing disease risk. This may be due to individual variability in response. We used a multi-platform lipidomic approach to investigate both the consistent and inconsistent responses of individuals comprehensively to a defined ω3 intervention. Methods The lipidomic profile including fatty acids, lipid classes, lipoprotein distribution, and oxylipins was examined multi- and uni-variately in 12 healthy subjects pre vs. post six weeks of ω3 fatty acids (1.9 g/d eicosapentaenoic acid [EPA] and 1.5 g/d docosahexaenoic acid [DHA]). Results Total lipidomic and oxylipin profiles were significantly different pre vs. post treatment across all subjects (p=0.00007 and p=0.00002 respectively). There was a strong correlation between oxylipin profiles and EPA and DHA incorporated into different lipid classes (r2=0.93). However, strikingly divergent responses among individuals were also observed. Both ω3 and ω6 fatty acid metabolites displayed a large degree of variation among the subjects. For example, in half of the subjects, two arachidonic acid cyclooxygenase products, prostaglandin E2 (PGE2) and thromboxane B2 (TXB2), and a lipoxygenase product, 12-hydroxyeicosatetraenoic acid (12-HETE) significantly decreased post intervention, whereas in the other half they either did not change or increased. The EPA lipoxygenase metabolite 12-hydroxyeicosapentaenoic acid (12-HEPE) varied among subjects from an 82% decrease to a 5,000% increase. Conclusions Our results show that certain defined responses to ω3 fatty acid intervention were consistent across all subjects. However, there was also a high degree of inter-individual variability in certain aspects of lipid metabolism. This lipidomic based phenotyping approach demonstrated that individual responsiveness to ω3 fatty acids is highly variable and measurable, and could be

  8. Exocrine pancreatic response to intraduodenal fatty acids and fats in rabbits.

    PubMed

    Navas, J M; Calvo, J J; López, M A; De Dios, I

    1993-05-01

    1. The exocrine pancreatic secretion in rabbits after intraduodenal perfusion of, respectively, a short-chain fatty acid (propionate), a long-chain fatty acid (oleate) and a neutral fat (intralipid) has been studied. 2. Only the neutral fat and the long-chain fatty acid stimulated the hydroelectrolyte fraction of exocrine pancreatic secretion in a dose-related fashion, but this response was not mediated by secretin release. 3. Acinar secretion was more effectively stimulated after propionate perfusion than by oleate and this was governed by different mechanisms. 4. Neutral fat, without predigestion, stimulated the pancreatic enzyme secretion in the rabbit. PMID:8099868

  9. Increased acid responsiveness in vagal sensory neurons in a guinea pig model of eosinophilic esophagitis

    PubMed Central

    Hu, Youtian; Liu, Zhenyu; Yu, Xiaoyun; Pasricha, Pankaj J.; Undem, Bradley J.

    2014-01-01

    Eosinophilic esophagitis (EoE) is characterized with eosinophils and mast cells predominated allergic inflammation in the esophagus and present with esophageal dysfunctions such as dysphagia, food impaction, and heartburn. However, the underlying mechanism of esophageal dysfunctions is unclear. This study aims to determine whether neurons in the vagal sensory ganglia are modulated in a guinea pig model of EoE. Animals were actively sensitized by ovalbumin (OVA) and then challenged with aerosol OVA inhalation for 2 wk. This results in a mild esophagitis with increases in mast cells and eosinophils in the esophageal wall. Vagal nodose and jugular neurons were disassociated, and their responses to acid, capsaicin, and transient receptor potential vanilloid type 1 (TRPV1) antagonist AMG-9810 were studied by calcium imaging and whole cell patch-clamp recording. Compared with naïve animals, antigen challenge significantly increased acid responsiveness in both nodose and jugular neurons. Their responses to capsaicin were also increased after antigen challenge. AMG-9810, at a concentration that blocked capsaicin-evoked calcium influx, abolished the increase in acid-induced activation in both nodose and jugular neurons. Vagotomy strongly attenuated those increased responses of nodose and jugular neurons to both acid and capsaicin induced by antigen challenge. These data for the first time demonstrated that prolonged antigen challenge significantly increases acid responsiveness in vagal nodose and jugular ganglia neurons. This sensitization effect is mediated largely through TRPV1 and initiated at sensory nerve endings in the peripheral tissues. Allergen-induced enhancement of responsiveness to noxious stimulation by acid in sensory nerve may contribute to the development of esophageal dysfunctions such as heartburn in EoE. PMID:24875100

  10. Nrf2-dependent and -independent Responses to Nitro-fatty Acids in Human Endothelial Cells

    PubMed Central

    Kansanen, Emilia; Jyrkkänen, Henna-Kaisa; Volger, Oscar L.; Leinonen, Hanna; Kivelä, Annukka M.; Häkkinen, Sanna-Kaisa; Woodcock, Steven R.; Schopfer, Francisco J.; Horrevoets, Anton J.; Ylä-Herttuala, Seppo; Freeman, Bruce A.; Levonen, Anna-Liisa

    2009-01-01

    Electrophilic fatty acid derivatives, including nitrolinoleic acid and nitro-oleic acid (OA-NO2), can mediate anti-inflammatory and pro-survival signaling reactions. The transcription factor Nrf2, activated by electrophilic fatty acids, suppresses redox-sensitive pro-inflammatory gene expression and protects against vascular endothelial oxidative injury. It was therefore postulated that activation of Nrf2 by OA-NO2 accounts in part for its anti-inflammatory actions, motivating the characterization of Nrf2-dependent and -independent effects of OA-NO2 on gene expression using genome-wide transcriptional profiling. Control and Nrf2-small interfering RNA-transfected human endothelial cells were treated with vehicle, oleic acid, or OA-NO2, and differential gene expression profiles were determined. Although OA-NO2 significantly induced the expression of Nrf2-dependent genes, including heme oxygenase-1 and glutamate-cysteine ligase modifier subunit, the majority of OA-NO2-regulated genes were regulated by Nrf2-independent pathways. Moreover, gene set enrichment analysis revealed that the heat shock response is the major pathway activated by OA-NO2, with robust induction of a number of heat shock genes regulated by the heat shock transcription factor. Inasmuch as the heat shock response mediates anti-inflammatory and cytoprotective actions, this mechanism is proposed to contribute to the protective cell signaling functions of nitro-fatty acids and other electrophilic fatty acid derivatives. PMID:19808663

  11. A low-pH-inducible, stationary-phase acid tolerance response in Salmonella typhimurium.

    PubMed Central

    Lee, I S; Slonczewski, J L; Foster, J W

    1994-01-01

    Acid is an important environmental condition encountered by Salmonella typhimurium during its pathogenesis. Our studies have shown that the organism can actively adapt to survive potentially lethal acid exposures by way of at least three possibly overlapping systems. The first is a two-stage system induced in response to low pH by logarithmic-phase cells called the log-phase acid tolerance response (ATR). It involves a major molecular realignment of the cell including the induction of over 40 proteins. The present data reveal that two additional systems of acid resistance occur in stationary-phase cells. One is a pH-dependent system distinct from log-phase ATR called stationary-phase ATR. It was shown to provide a higher level of acid resistance than log-phase ATR but involved the synthesis of fewer proteins. Maximum induction of stationary-phase ATR occurred at pH 4.3. A third system of acid resistance is not induced by low pH but appears to be part of a general stress resistance induced by stationary phase. This last system requires the alternative sigma factor, RpoS. Regulation of log-phase ATR and stationary-phase ATR remains RpoS independent. Although the three systems are for the most part distinct from each other, together they afford maximum acid resistance for S. typhimurium. Images PMID:8113183

  12. pH-responsive fatty acid self-assembly transition induced by UV light.

    PubMed

    Arnould, Audrey; Gaillard, Cedric; Fameau, Anne-Laure

    2015-11-15

    Fatty acids are natural, pH-responsive surfactants. Their properties can be tuned by adding CO2 or by applying light which modify solution pH. We investigated photoresponsive systems based on fatty acids with different chain lengths in the presence of a photoacid generator (PAG). Under UV irradiation, photolysis of the PAG in aqueous solution resulted in a decrease in pH, triggering a change in fatty acid assembly. Using a multi-scale approach before and after UV irradiation, we characterized the effect of this pH decrease on the nature of the fatty acid self-assemblies. At the molecular scale, pH and infrared spectroscopy measurements were used to determine the fatty acid ionization state. At the microscopic scale, the self-assembled structure was characterized using small-angle neutron scattering and microscopy. We showed that UV irradiation tuned the ionization state of the fatty acid molecules which in turn triggered a transition from spherical micelles to vesicles or lamellar phases, depending on fatty acid chain length. We studied the foaming properties of these systems before and after UV irradiation. We showed that after UV irradiation, foam stability was drastically enhanced as a result of a change in self-assembly. Our approach can be easily extended to various pH-responsive surfactants. PMID:26210918

  13. Effect of co-ingestion of amino acids with rice on glycaemic and insulinaemic response.

    PubMed

    Soong, Yean Yean; Lim, Joseph; Sun, Lijuan; Henry, Christiani Jeyakumar

    2015-12-14

    Consumption of high glycaemic index (GI) and glycaemic response (GR) food such as white rice has been implicated in the development of type 2 diabetes. Previous studies have reported the ability of individual amino acids to reduce GR of carbohydrate-rich foods. Because of the bitter flavour of amino acids, they have rarely been used to reduce GR. We now report the use of a palatable, preformed amino acid mixture in the form of essence of chicken. In all, sixteen healthy male Chinese were served 68 or 136 ml amino acid mixture together with rice, or 15 or 30 min before consumption of white rice. Postprandial blood glucose and plasma insulin concentrations were measured at fasting and every 15 min after consumption of the meal until 60 min after the consumption of the white rice. Subsequent blood samples were taken at 30-min intervals until 210 min. The co-ingestion of 68 ml of amino acid mixture with white rice produced the best results in reducing the peak blood glucose and GR of white rice without increasing the insulinaemic response. It is postulated that amino acid mixtures prime β-cell insulin secretion and peripheral tissue uptake of glucose. The use of ready-to-drink amino acid mixtures may be a useful strategy for lowering the high-GI rice diets consumed in Asia. PMID:26420496

  14. Gustatory responsiveness to the 20 proteinogenic amino acids in the spider monkey (Ateles geoffroyi).

    PubMed

    Larsson, Jenny; Maitz, Anna; Hernandez Salazar, Laura Teresa; Laska, Matthias

    2014-03-29

    The gustatory responsiveness of four adult spider monkeys to the 20 proteinogenic amino acids was assessed in two-bottle preference tests of brief duration (1min). We found that Ateles geoffroyi responded with significant preferences for seven amino acids (glycine, l-proline, l-alanine, l-serine, l-glutamic acid, l-aspartic acid, and l-lysine) when presented at a concentration of 100mM and/or 200mM and tested against water. At the same concentrations, the animals significantly rejected five amino acids (l-tryptophan, l-tyrosine, l-valine, l-cysteine, and l-isoleucine) and were indifferent to the remaining tastants. Further, the results show that the spider monkeys discriminated concentrations as low as 0.2mM l-lysine, 2mM l-glutamic acid, 10mM l-proline, 20mM l-valine, 40mM glycine, l-serine, and l-aspartic acid, and 80mM l-alanine from the alternative stimulus, with individual animals even scoring lower threshold values. A comparison between the taste qualities of the proteinogenic amino acids as described by humans and the preferences and aversions observed in the spider monkeys suggests a fairly high degree of agreement in the taste quality perception of these tastants between the two species. A comparison between the taste preference thresholds obtained with the spider monkeys and taste detection thresholds reported in human subjects suggests that the taste sensitivity of A. geoffroyi for the amino acids tested here might match that of Homo sapiens. The results support the assumption that the taste responses of spider monkeys to proteinogenic amino acids might reflect an evolutionary adaptation to their frugivorous and thus protein-poor diet. PMID:24480073

  15. Physiological and proteomic analysis of Lactobacillus casei in response to acid adaptation.

    PubMed

    Wu, Chongde; He, Guiqiang; Zhang, Juan

    2014-10-01

    The aim of this study was to investigate the acid tolerance response (ATR) in Lactobacillus casei by a combined physiological and proteomic analysis. To optimize the ATR induction, cells were acid adapted for 1 h at different pHs, and then acid challenged at pH 3.5. The result showed that acid adaptation improved acid tolerance, and the highest survival was observed in cells adapted at pH 4.5 for 1 h. Analysis of the physiological data showed that the acid-adapted cells exhibited higher intracellular pH (pHi), intracellular NH4 (+) content, and lower inner permeability compared with the cells without adaptation. Proteomic analysis was performed upon acid adaptation to different pHs (pH 6.5 vs. pH 4.5) using two-dimensional electrophoresis. A total of 24 proteins that exhibited at least 1.5-fold differential expression were identified. Four proteins (Pgk, LacD, Hpr, and Galm) involved in carbohydrate catabolism and five classic stress response proteins (GroEL, GrpE, Dnak, Hspl, and LCAZH_2811) were up-regulated after acid adaptation at pH 4.5 for 1 h. Validation of the proteomic data was performed by quantitative RT-PCR, and transcriptional regulation of all selected genes showed a positive correlation with the proteomic patterns of the identified proteins. Results presented in this study may be useful for further elucidating the acid tolerance mechanisms and may help in formulating new strategies to improve the industrial performance of this species during acid stress. PMID:25062817

  16. Glutathione is involved in physiological response of Candida utilis to acid stress.

    PubMed

    Wang, Da-Hui; Zhang, Jun-Li; Dong, Ying-Ying; Wei, Gong-Yuan; Qi, Bin

    2015-12-01

    Candida utilis often encounters an acid stress environment when hexose and pentose are metabolized to produce acidic bio-based materials. In order to reveal the physiological role of glutathione (GSH) in the response of cells of this industrial yeast to acid stress, an efficient GSH-producing strain of C. utilis CCTCC M 209298 and its mutants deficient in GSH biosynthesis, C. utilis Δgsh1 and Δgsh2, were used in this study. A long-term mild acid challenge (pH 3.5 for 6 h) and a short-term severe acid challenge (pH 1.5 for 2 h) were conducted at 18 h during batch culture of the yeast to generate acid stress conditions. Differences in the physiological performances among the three strains under acid stress were analyzed in terms of GSH biosynthesis and distribution; intracellular pH; activities of γ-glutamylcysteine synthetase, catalase, and superoxide dismutase; intracellular ATP level; and ATP/ADP ratio. The intracellular GSH content of the yeast was found to be correlated with changes in physiological data, and a higher intracellular GSH content led to greater relief of cells to the acid stress, suggesting that GSH may be involved in protecting C. utilis against acid stress. Results presented in this manuscript not only increase our understanding of the impact of GSH on the physiology of C. utilis but also help us to comprehend the mechanism underlying the response to acid stress of eukaryotic microorganisms. PMID:26346268

  17. Response of Cultured Maize Cells to (+)-Abscisic Acid, (-)-Abscisic Acid, and Their Metabolites.

    PubMed Central

    Balsevich, J. J.; Cutler, A. J.; Lamb, N.; Friesen, L. J.; Kurz, E. U.; Perras, M. R.; Abrams, S. R.

    1994-01-01

    The metabolism and effects of (+)-S- and (-)-R-abscisic acid (ABA) and some metabolites were studied in maize (Zea mays L. cv Black Mexican Sweet) suspension-cultured cells. Time-course studies of metabolite formation were performed in both cells and medium via analytical high-performance liquid chromatography. Metabolites were isolated and identified using physical and chemical methods. At 10 [mu]M concentration and 28[deg] C, (+)-ABA was metabolized within 24 h, yielding natural (-)-phaseic acid [(-)-PA] as the major product. The unnatural enantiomer (-)-ABA was less than 50% metabolized within 24 h and gave primarily (-)-7[prime]-hydroxyABA [(-)-7[prime]-HOABA], together with (+)-PA and ABA glucose ester. The distribution of metabolites in cells and medium was different, reflecting different sites of metabolism and membrane permeabilities of conjugated and nonconjugated metabolites. The results imply that (+)-ABA was oxidized to (-)-PA inside the cell, whereas (-)-ABA was converted to (-)-7[prime]-HOABA at the cell surface. Growth of maize cells was inhibited by both (+)- and (-)-ABA, with only weak contributions from their metabolites. The concentration of (+)-ABA that caused a 50% inhibition of growth of maize cells was approximately 1 [mu]M, whereas that for its metabolite (-)-PA was approximately 50 [mu]M. (-)-ABA was less active than (+)-ABA, with 50% growth inhibition observed at about 10 [mu]M. (-)-7[prime]-HOABA was only weakly active, with 50% inhibition caused by approximately 500 [mu]M. Time-course studies of medium pH indicated that (+)-ABA caused a transient pH increase (+0.3 units) at 6 h after addition that was not observed in controls or in samples treated with (-)-PA. The effect of (-)-ABA on medium Ph was marginal. No racemization at C-1[prime] of (+)-ABA, (-)-ABA, or metabolites was observed during the studies. PMID:12232311

  18. An attempt to validate the ultra-accelerated microbar and the concrete performance test with the degree of AAR-induced damage observed in concrete structures

    SciTech Connect

    Leemann, Andreas; Merz, Christine

    2013-07-15

    There is little knowledge about the relation between AAR-induced damage observed in structures and the expansion potential obtained with accelerated tests. In this study, aggregates used in structures damaged by AAR were tested with the microbar test (MBT/AFNOR XP 18-594) and the concrete performance test (CPT/AFNOR P18-454). After the tests, the samples were examined using optical and scanning electron microscopy. Based on the results, the significance of the microbar test has to be examined very critically. The agreement of measured expansion, reacted rock types and the composition of the reaction products between the on-site concrete and the reproduced concrete subjected to the CPT clearly indicates that the reaction mechanisms in the structure and in the concrete performance test are comparable. As such, the concrete performance test seems to be an appropriate tool to test the potential reactivity of specific concrete mixtures.

  19. A one- and two-dimensional cross-section sensitivity and uncertainty path of the AARE (Advanced Analysis for Reactor Engineering) modular code system

    SciTech Connect

    Davidson, J.W.; Dudziak, D.J.; Higgs, C.E.; Stepanek, J.

    1988-01-01

    AARE, a code package to perform Advanced Analysis for Reactor Engineering, is a linked modular system for fission reactor core and shielding, as well as fusion blanket, analysis. Its cross-section sensitivity and uncertainty path presently includes the cross-section processing and reformatting code TRAMIX, cross-section homogenization and library reformatting code MIXIT, the 1-dimensional transport code ONEDANT, the 2-dimensional transport code TRISM, and the 1- and 2- dimensional cross-section sensitivity and uncertainty code SENSIBL. IN the present work, a short description of the whole AARE system is given, followed by a detailed description of the cross-section sensitivity and uncertainty path. 23 refs., 2 figs.

  20. This NASA Dryden F/A-18 is participating in the Automated Aerial Refueling (AAR) project. F/A-18 (No

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A NASA Dryden F/A-18 is participating in the Automated Aerial Refueling (AAR) project. F/A-18 (No. 847) is acting as an in-flight refueling tanker in the study to develop analytical models for an automated aerial refueling system for unmanned vehicles. A 300-gallon aerodynamic pod containing air-refueling equipment is seen beneath the fuselage. The hose and refueling basket are extended during an assessment of their dynamics on the F/A-18A.

  1. Dynamics of Responses in Compatible Potato - Potato virus Y Interaction Are Modulated by Salicylic Acid

    PubMed Central

    Baebler, Špela; Stare, Katja; Kovač, Maja; Blejec, Andrej; Prezelj, Nina; Stare, Tjaša; Kogovšek, Polona; Pompe-Novak, Maruša; Rosahl, Sabine; Ravnikar, Maja; Gruden, Kristina

    2011-01-01

    To investigate the dynamics of the potato – Potato virus Y (PVY) compatible interaction in relation to salicylic acid - controlled pathways we performed experiments using non-transgenic potato cv. Désirée, transgenic NahG-Désirée, cv. Igor and PVYNTN, the most aggressive strain of PVY. The importance of salicylic acid in viral multiplication and symptom development was confirmed by pronounced symptom development in NahG-Désirée, depleted in salicylic acid, and reversion of the effect after spraying with 2,6-dichloroisonicotinic acid (a salicylic acid - analogue). We have employed quantitative PCR for monitoring virus multiplication, as well as plant responses through expression of selected marker genes of photosynthetic activity, carbohydrate metabolism and the defence response. Viral multiplication was the slowest in inoculated potato of cv. Désirée, the only asymptomatic genotype in the study. The intensity of defence-related gene expression was much stronger in both sensitive genotypes (NahG-Désirée and cv. Igor) at the site of inoculation than in asymptomatic plants (cv. Désirée). Photosynthesis and carbohydrate metabolism gene expression differed between the symptomatic and asymptomatic phenotypes. The differential gene expression pattern of the two sensitive genotypes indicates that the outcome of the interaction does not rely simply on one regulatory component, but similar phenotypical features can result from distinct responses at the molecular level. PMID:22194976

  2. Dietary essential fatty acids and gender-specific behavioral responses in cranially irradiated rats

    PubMed Central

    Elkin, T David; Wollan, Michael O; Anderson, Stacy L; Gaston, Robert; Meyer, William; Fuemmeler, Bernard F; Holloway, Frank A; Martin, Rex E

    2006-01-01

    Specific memory deficits, reduced intellectual processing speed, and a variety of social and behavioral problems have been implicated as long-term effects of cranial radiation therapy (CRT). These deficits are thought to be related to changes in brain cytology and structure associated with microvascular aberrations. N-3 fatty acids may serve as protectants in pediatric patients who receive CRT for brain tumors. Timed-pregnant rat dams were fed one of four diets that were identical in all respects, except for their essential fatty acid content. The dams were placed on these diets at the beginning of the third trimester of gestation and their pups remained on them throughout the study. The rats’ behavioral response as judged by acoustic startle response (ASR) and neurocognitive response (performance in a radial maze, RM) were evaluated in relation to diet, gender, and CRT. The following hypotheses were tested: (1) female rats will show greater CRT-induced neurocognitive and behavioral deficits; (2) dietary n-3 fatty acids will diminish CRT-induced neurocognitive and behavioral deficits; (3) gender-specific differences would be dampened by n-3 fatty acids in the diet. All three hypotheses were partially supported. These findings are discussed in light of the potential neuroprotective effects of n-3 fatty acids. PMID:19412484

  3. Jasmonic acid interacts with abscisic acid to regulate plant responses to water stress conditions

    PubMed Central

    de Ollas, Carlos; Arbona, Vicent; Gómez-Cadenas, Aurelio

    2015-01-01

    Phytohormones are key players in signaling environmental stress conditions. Hormone profiling together with proline accumulation were studied in leaves and roots of different mutant lines of Arabidopsis. Regulation of proline accumulation in this system seems complex and JA-deficient (jar1-1) and JA-insensitive (jai1) lines accumulating high levels of proline despite their very low ABA levels seems to discard an ABA-dependent response. However, the pattern of proline accumulation in jai1 seedlings parallels that of ABA. Under stress conditions, there is an opposite pattern of ABA accumulation in roots of jar1-1/coi1-16 (in which ABA only slightly increase) and jai1 (in which ABA increase is even higher than in WT plants). This also makes JA-ABA crosstalk complex and discards any lineal pathway that could explain this hormonal interaction. PMID:26340066

  4. Jasmonic acid interacts with abscisic acid to regulate plant responses to water stress conditions.

    PubMed

    de Ollas, Carlos; Arbona, Vicent; Gómez-Cadenas, Aurelio

    2015-01-01

    Phytohormones are key players in signaling environmental stress conditions. Hormone profiling together with proline accumulation were studied in leaves and roots of different mutant lines of Arabidopsis. Regulation of proline accumulation in this system seems complex and JA-deficient (jar1-1) and JA-insensitive (jai1) lines accumulating high levels of proline despite their very low ABA levels seems to discard an ABA-dependent response. However, the pattern of proline accumulation in jai1 seedlings parallels that of ABA. Under stress conditions, there is an opposite pattern of ABA accumulation in roots of jar1-1/coi1-16 (in which ABA only slightly increase) and jai1 (in which ABA increase is even higher than in WT plants). This also makes JA-ABA crosstalk complex and discards any lineal pathway that could explain this hormonal interaction. PMID:26340066

  5. Molecular mechanisms of Saccharomyces cerevisiae stress adaptation and programmed cell death in response to acetic acid

    PubMed Central

    Giannattasio, Sergio; Guaragnella, Nicoletta; Ždralević, Maša; Marra, Ersilia

    2013-01-01

    Beyond its classical biotechnological applications such as food and beverage production or as a cell factory, the yeast Saccharomyces cerevisiae is a valuable model organism to study fundamental mechanisms of cell response to stressful environmental changes. Acetic acid is a physiological product of yeast fermentation and it is a well-known food preservative due to its antimicrobial action. Acetic acid has recently been shown to cause yeast cell death and aging. Here we shall focus on the molecular mechanisms of S. cerevisiae stress adaptation and programmed cell death in response to acetic acid. We shall elaborate on the intracellular signaling pathways involved in the cross-talk of pro-survival and pro-death pathways underlying the importance of understanding fundamental aspects of yeast cell homeostasis to improve the performance of a given yeast strain in biotechnological applications. PMID:23430312

  6. Molecular mechanisms of Saccharomyces cerevisiae stress adaptation and programmed cell death in response to acetic acid.

    PubMed

    Giannattasio, Sergio; Guaragnella, Nicoletta; Zdralević, Maša; Marra, Ersilia

    2013-01-01

    Beyond its classical biotechnological applications such as food and beverage production or as a cell factory, the yeast Saccharomyces cerevisiae is a valuable model organism to study fundamental mechanisms of cell response to stressful environmental changes. Acetic acid is a physiological product of yeast fermentation and it is a well-known food preservative due to its antimicrobial action. Acetic acid has recently been shown to cause yeast cell death and aging. Here we shall focus on the molecular mechanisms of S. cerevisiae stress adaptation and programmed cell death in response to acetic acid. We shall elaborate on the intracellular signaling pathways involved in the cross-talk of pro-survival and pro-death pathways underlying the importance of understanding fundamental aspects of yeast cell homeostasis to improve the performance of a given yeast strain in biotechnological applications. PMID:23430312

  7. Light and acid dual-responsive organogel formation based on m-methyl red derivative.

    PubMed

    Cao, Xinhua; Gao, Aiping; Lv, Haiting; Wu, Yan; Wang, Xiuxiu; Fan, Yang

    2013-12-01

    A new gelator 1 that included m-methyl red was synthesized and fully characterized. It was found that the organogel of 1 was stable in DMSO even if the organogel was stimulated by acid or light. The organogel was thoroughly characterized using various microscopic techniques including field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), UV-vis and Fourier transform infrared (FTIR) spectra. The organogel exhibited tunable structures and optical properties under different stimulation. The regular nanoring structure was turned into microspheres after the organogel in DMSO was stimulated at 254 nm light or acid. At the same time, the color of molecule 1 in gel state and solution state was all changed after stimulation by light or acid. The hydrogen bonding and π-π stacking were found to be the main driving forces for gel formation. This dual-responsive gel held promise for soft materials application in upscale smart responsive materials. PMID:24135789

  8. Proteomic characterization of acid stress response in Synechocystis sp. PCC 6803.

    PubMed

    Kurian, Dominic; Phadwal, Kanchan; Mäenpää, Pirkko

    2006-06-01

    A comparative proteomic analysis using 2-DE coupled with MALDI-MS and LC-MS/MS was performed in Synechocystis sp. PCC 6803 to identify protein candidates involved in acid stress response in cyanobacteria. Comparison of soluble proteins from the cytoplasmic fraction of cells grown on media set at pH 7.5 and 5.5 using 2-DE identified four proteins, which showed significant changes in the abundance. Surprisingly, several general stress proteins, either the heat shock family proteins or chaperonins, did not show perceptible fold changes in response to acidity. Compared to the cytoplasmic proteome, the periplasmic proteome showed remarkable changes as a function of external pH. Protein expression profiling at different external pH, i.e., 9.0, 7.5, 6.0 and 5.5, allowed classifying the periplasmic proteins depending on their preferential expression patterns towards acidity or alkalinity. Among the acid- and base-induced proteins, oxalate decarboxylase and carbonic anhydrase were already known for their role in pH homeostasis. Several unknown proteins from the periplasm, that showed significant changes in response to pH, provide ideal targets for further studies in understanding pH stress response in cyanobacteria. This study also identified 14 novel proteins, hitherto unknown from the periplasmic space of Synechocystis. PMID:16691555

  9. Response to oxalic acid as a resistance assay for Sclerotinia minor in peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Response to oxalic acid was evaluated as a potential assay for screening peanut breeding lines for resistance to Sclerotinia blight caused by Sclerotinia minor. Detached stems of seven Spanish- and six runner-type peanut cultivars and advanced breeding lines, varying in resistance to Sclerotinia bl...

  10. Short chain fatty acid production and glucose responses by methane producers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fermentation by gut microbiota has been linked to physiologic responses in the host. Methanogenic gut bacteria may remove more carbon from indigestible food matrices especially poorly digested carbohydrates. We sought to assess the effects of methane production on short chain fatty acid (SCFA) con...

  11. Dual pH-responsive 5-aminolevulinic acid pseudopolyrotaxane prodrug micelles for enhanced photodynamic therapy.

    PubMed

    Tong, Hongxin; Wang, Yin; Li, Huan; Jin, Qiao; Ji, Jian

    2016-03-11

    Novel 5-aminolevulinic acid (ALA) pseudopolyrotaxane prodrug micelles with dual pH-responsive properties were prepared by the host-guest interaction of α-cyclodextrin (α-CD) and poly(ethylene glycol) (PEG). The micelles exhibited pH dependent cellular uptake and pH-sensitive ALA release, enabling enhanced photodynamic therapy. PMID:26882232

  12. Response of DOC in acid-sensitive Maine lakes to decreasing sulfur deposition (1993 - 2009)

    EPA Science Inventory

    In response to the Clean Air Act Amendments of 1990, sulfur deposition has decreased across the northeastern United States. As a result, sulfate concentrations in lakes and streams have also decreased and many surface waters have become less acidic. Over the same time period, th...

  13. MODELING THE RESPONSE OF GREENHOUSE-GROWN RADISH PLANTS TO ACIDIC RAIN

    EPA Science Inventory

    The emphasis being placed on the need for assessments to determine the impacts of acidic rain has resulted in the initiation of many dose-response studies. Experimental design parameters and model evaluation play important roles in the overall conclusions of such studies. To illu...

  14. Gene-related strain variation of Staphylococcus aureus for homologous resistance response to acid stress.

    PubMed

    Lee, Soomin; Ahn, Sooyeon; Lee, Heeyoung; Kim, Won-Il; Kim, Hwang-Yong; Ryu, Jae-Gee; Kim, Se-Ri; Choi, Kyoung-Hee; Yoon, Yohan

    2014-10-01

    This study investigated the effect of adaptation of Staphylococcus aureus strains to the acidic condition of tomato in response to environmental stresses, such as heat and acid. S. aureus ATCC 13565, ATCC 14458, ATCC 23235, ATCC 27664, and NCCP10826 habituated in tomato extract at 35°C for 24 h were inoculated in tryptic soy broth. The culture suspensions were then subjected to heat challenge or acid challenge at 60°C and pH 3.0, respectively, for 60 min. In addition, transcriptional analysis using quantitative real-time PCR was performed to evaluate the expression level of acid-shock genes, such as clpB, zwf, nuoF, and gnd, from five S. aureus strains after the acid habituation of strains in tomato at 35°C for 15 min and 60 min in comparison with that of the nonhabituated strains. In comparison with the nonhabituated strains, the five tomato-habituated S. aureus strains did not show cross protection to heat, but tomato-habituated S. aureus ATCC 23235 showed acid resistance. In quantitative real-time-PCR analysis, the relative expression levels of acid-shock genes (clpB, zwf, nuoF, and gnd) were increased the most in S. aureus ATCC 23235 after 60 min of tomato habituation, but there was little difference in the expression levels among the five S. aureus strains after 15 min of tomato habituation. These results indicate that the variation of acid resistance of S. aureus is related to the expression of acid-shock genes during acid habituation. PMID:25285500

  15. Abscisic Acid Elicits the Water-Stress Response in Root Hairs of Arabidopsis thaliana1

    PubMed Central

    Schnall, Jennifer A.; Quatrano, Ralph S.

    1992-01-01

    Water stress has been shown to cause root hairs to become short and bulbous. Because abscisic acid (ABA) mediates a variety of water-stress responses, we investigated the response of Arabidopsis thaliana root hairs to ABA. When wild-type root hairs were treated with ABA, they exhibited the water-stress response. The Arabidopsis mutants abi1 and abi2, which are insensitive to ABA at the seedling stage, did not display the root hair response. These data suggest that ABA may mediate the response of root hairs to water stress. The drought response of root hairs resulting in an inhibition of tip growth will provide an easy screen to select mutations that are insensitive to ABA and/or involved in tip growth. Images Figure 1 PMID:16652949

  16. Learned olfactory discrimination versus innate taste responses to amino acids in channel catfish (Ictalurus punctatus).

    PubMed

    Valentincic, T; Wegert, S; Caprio, J

    1994-05-01

    Intact channel catfish conditioned to the L-amino acids, proline, arginine, alanine, and lysine, discriminated these stimuli from all other amino acids tested. Behavioral structure-activity tests indicated that L-pipecolate was the only effective agonist of the L-proline conditioned response. For channel catfish in which one of the paired olfactory organs was surgically removed, the number of turns to the conditioned stimulus was 40% fewer than those of intact catfish; however, these semiosmic channel catfish discriminated the conditioned from nonconditioned stimuli, as evidenced by their responding to the conditioned amino acid, with a two- to threefold greater number of turns than to the nonconditioned amino acids. Irrespective of the number of conditioning trials attempted, catfish with both olfactory organs removed were unable to discriminate the conditioned from the nonconditioned stimuli. PMID:8022906

  17. Targeting amino acid metabolism in cancer growth and anti-tumor immune response

    PubMed Central

    Ananieva, Elitsa

    2015-01-01

    Recent advances in amino acid metabolism have revealed that targeting amino acid metabolic enzymes in cancer therapy is a promising strategy for the development of novel therapeutic agents. There are currently several drugs in clinical trials that specifically target amino acid metabolic pathways in tumor cells. In the context of the tumor microenvironment, however, tumor cells form metabolic relationships with immune cells, and they often compete for common nutrients. Many tumors evolved to escape immune surveillance by taking advantage of their metabolic flexibility and redirecting nutrients for their own advantage. This review outlines the most recent advances in targeting amino acid metabolic pathways in cancer therapy while giving consideration to the impact these pathways may have on the anti-tumor immune response. PMID:26629311

  18. Plants having modified response to ethylene by transformation with an ETR nucleic acid

    DOEpatents

    Meyerowitz, Elliott M.; Chang, Caren; Bleecker, Anthony B.

    2001-01-01

    The invention includes transformed plants having at least one cell transformed with a modified ETR nucleic acid. Such plants have a phenotype characterized by a decrease in the response of at least one transformed plant cell to ethylene as compared to a plant not containing the transformed plant cell. Tissue and/or temporal specificity for expression of the modified ETR nucleic acid is controlled by selecting appropriate expression regulation sequences to target the location and/or time of expression of the transformed nucleic acid. The plants are made by transforming at least one plant cell with an appropriate modified ETR nucleic acid, regenerating plants from one or more of the transformed plant cells and selecting at least one plant having the desired phenotype.

  19. Proteomic analysis of the molecular response of Raji cells to maslinic acid treatment.

    PubMed

    Yap, W H; Khoo, K S; Lim, S H; Yeo, C C; Lim, Y M

    2012-01-15

    Maslinic acid, a natural pentacyclic triterpene has been shown to inhibit growth and induce apoptosis in some tumour cell lines. We studied the molecular response of Raji cells towards maslinic acid treatment. A proteomics approach was employed to identify the target proteins. Seventeen differentially expressed proteins including those involved in DNA replication, microtubule filament assembly, nucleo-cytoplasmic trafficking, cell signaling, energy metabolism and cytoskeletal organization were identified by MALDI TOF-TOF MS. The down-regulation of stathmin, Ran GTPase activating protein-1 (RanBP1), and microtubule associated protein RP/EB family member 1 (EB1) were confirmed by Western blotting. The study of the effect of maslinic acid on Raji cell cycle regulation showed that it induced a G1 cell cycle arrest. The differential proteomic changes in maslinic acid-treated Raji cells demonstrated that it also inhibited expression of dUTPase and stathmin which are known to induce early S and G2 cell cycle arrests. The mechanism of maslinic acid-induced cell cycle arrest may be mediated by inhibiting cyclin D1 expression and enhancing the levels of cell cycle-dependent kinase (CDK) inhibitor p21 protein. Maslinic acid suppressed nuclear factor-kappa B (NF-κB) activity which is known to stimulate expression of anti-apoptotic and cell cycle regulatory gene products. These results suggest that maslinic acid affects multiple signaling molecules and inhibits fundamental pathways regulating cell growth and survival in Raji cells. PMID:21893403

  20. eIF4A inactivates TORC1 in response to amino acid starvation.

    PubMed

    Tsokanos, Foivos-Filippos; Albert, Marie-Astrid; Demetriades, Constantinos; Spirohn, Kerstin; Boutros, Michael; Teleman, Aurelio A

    2016-05-17

    Amino acids regulate TOR complex 1 (TORC1) via two counteracting mechanisms, one activating and one inactivating. The presence of amino acids causes TORC1 recruitment to lysosomes where TORC1 is activated by binding Rheb. How the absence of amino acids inactivates TORC1 is less well understood. Amino acid starvation recruits the TSC1/TSC2 complex to the vicinity of TORC1 to inhibit Rheb; however, the upstream mechanisms regulating TSC2 are not known. We identify here the eIF4A-containing eIF4F translation initiation complex as an upstream regulator of TSC2 in response to amino acid withdrawal in Drosophila We find that TORC1 and translation preinitiation complexes bind each other. Cells lacking eIF4F components retain elevated TORC1 activity upon amino acid removal. This effect is specific for eIF4F and not a general consequence of blocked translation. This study identifies specific components of the translation machinery as important mediators of TORC1 inactivation upon amino acid removal. PMID:26988032

  1. Monitoring responses of Mason Pine to acid rain in China based on remote sensing vegetation index

    NASA Astrophysics Data System (ADS)

    Jin, Jiaxin; Jiang, Hong; Hou, Chunliang; Zhang, Xiuying; Wang, Ying

    2014-03-01

    Since the 1970s, acid rain has remained in the public spotlight in both Europe and the United States and recently has emerged as an important problem in other regions such as Southeast Asia. To reveal responses of Masson Pine to acid rain during a long time series in central China, we used the interpolation dataset of acid rain and the Global Inventory Modeling and Mapping Studies (GIMMS) normalized difference vegetation index (NDVI) data to derive the monthly pH and NDVI trajectories based on acidity gradients from 1992 to 2006. Then we analyzed inter-annual and seasonal variation of vegetation growth by improved sinusoidal fitting and regression analysis. In the environment of strong acidity and moderate acidity, the growth of Masson Pine was inhibited during the study period, while the slight acidity promoted growth of Masson Pine to some extent. For the multi-year monthly changing trend of NDVI, late spring to mid autumn, the NDVI showed a decreasing trend, especially in June, while from late autumn to the following spring, the NDVI showed a rising tendency, specifically in December and March.

  2. Optimization of acid hydrolysis from the hemicellulosic fraction of Eucalyptus grandis residue using response surface methodology.

    PubMed

    Canettieri, Eliana Vieira; de Moraes Rocha, George Jackson; de Carvalho, João Andrade; de Almeida e Silva, João Batista

    2007-01-01

    Biotechnological conversion of biomass into fuels and chemicals requires hydrolysis of the polysaccharide fraction into monomeric sugars. Hydrolysis can be performed enzymatically and with dilute or concentrate mineral acids. The present study used dilute sulfuric acid as a catalyst for hydrolysis of Eucalyptus grandis residue. The purpose of this paper was to optimize the hydrolysis process in a 1.4 l pilot-scale reactor and investigate the effects of the acid concentration, temperature and residue/acid solution ratio on the hemicellulose removal and consequently on the production of sugars (xylose, glucose and arabinose) as well as on the formation of by-products (furfural, 5-hydroxymethylfurfural and acetic acid). This study was based on a model composition corresponding to a 2(3) orthogonal factorial design and employed the response surface methodology (RSM) to optimize the hydrolysis conditions, aiming to attain maximum xylose extraction from hemicellulose of residue. The considered optimum conditions were: H(2)SO(4) concentration of 0.65%, temperature of 157 degrees C and residue/acid solution ratio of 1/8.6 with a reaction time of 20 min. Under these conditions, 79.6% of the total xylose was removed and the hydrolysate contained 1.65 g/l glucose, 13.65 g/l xylose, 1.55 g/l arabinose, 3.10 g/l acetic acid, 1.23 g/l furfural and 0.20 g/l 5-hydroxymethylfurfural. PMID:16473004

  3. Sialic acids siglec interaction: A unique strategy to circumvent innate immune response by pathogens

    PubMed Central

    Khatua, Biswajit; Roy, Saptarshi; Mandal, Chitra

    2013-01-01

    Sialic acids (Sias) are nine-carbon keto sugars primarily present on the terminal residue of cell surface glycans. Sialic acid binding immunoglobulins (Ig)-like lectins (siglecs) are generally expressed on various immune cells. They selectively recognize different linkage-specific sialic acids and undertake a variety of cellular functions. Many pathogens either synthesize or acquire sialic acids from the host. Sialylated pathogens generally use siglecs to manipulate the host immune response. The present review mainly deals with the newly developed information regarding mechanism of acquisition of sialic acids by pathogens and their biological relevance especially in the establishment of successful infection by impairing host innate immunity. The pathogens which are unable to synthesize sialic acids might adsorb these from the host as a way to engage the inhibitory siglecs. They promote association with the immune cells through sialic acids-siglec dependent manner. Such an association plays an important role to subvert host's immunity. Detailed investigation of these pathways has been discussed in this review. Particular attention has been focused on Pseudomonas aeruginosa (PA) and Leishmania donovani. PMID:24434319

  4. Responses of Pisum sativum L. to exogenous indole acetic acid application under manganese toxicity.

    PubMed

    Gangwar, Savita; Singh, Vijay Pratap; Maurya, Jagat Narayan

    2011-06-01

    Responses of pea (Pisum sativum L.) seedlings to manganese (50, 100 and 250 μM) and indole acetic acid (10 and 100 μM) treatments were investigated. Single and combined exposure of pea to manganese and 100 μM indole acetic acid decreased root and shoot fresh mass, chlorophyll, carotenoids, protein and nitrogen while ammonium content increased compared to the control. Combined treatment of pea with 250 μM manganese and 100 μM indole acetic acid decreased root and shoot fresh mass by 54% and 51%, chlorophyll and carotenoids by 31% and 26%, root and shoot protein by 47% and 44%, and root and shoot nitrogen by 44% and 40%, respectively. Activities of glutamine synthetase and glutamate synthase were decreased by the exposure of manganese and 100 μM indole acetic acid while glutamate dehydrogenase activity increased. Combined application of 250 μM manganese and 100 μM indole acetic acid decreased root and shoot glutamine synthetase activity by 44% and 39%, and glutamate synthase activity by 39% and 37% while root and shoot glutamate dehydrogenase activity increased by 47% and 42%, respectively compared to the control. In contrast, application of 10 μM indole acetic acid together with manganese decreased the negative impacts of manganese, and promoted seedling growth compared to the manganese treatments alone. This study has shown that 10 μM indole acetic acid protected pea seedlings appreciably from manganese toxicity by regulating ammonium content and the activities of enzymes of ammonium assimilation, while 100 μM of indole acetic acid exhibited opposite response under manganese toxicity. PMID:21516457

  5. Acid-responsive properties of fibrils from heat-induced whey protein concentrate.

    PubMed

    Xu, Hong-Hua; Wang, Jing; Dong, Shi-Rong; Cheng, Wen; Kong, Bao-Hua; Tan, Jun-Yan

    2016-08-01

    The heat-induced fibrils of whey protein concentrate (WPC) have demonstrated an acid-responsive property; that is, the fibrils went through formation-depolymerization-reformation as pH was adjusted to 1.8, 6.5, and back to 1.8. We investigated the microstructure, driving force, and thermal stability of 3.0% (wt) WPC nanofibrils adjusted between pH 6.5 and 1.8 twice. The results showed that the nanofibrils had acid-responsive properties and good thermal stability after reheating for 10h at 90°C and adjusting pH from 1.8 to 6.5 to 1.8. The content of WPC fibril aggregates was not much different with the prolongation of heating times during pH variation. Although the nanofibrils' structure could be destroyed only by changing the pH, the essence of this destruction might only form fiber fragments, polymers that would restore a fibrous structure upon returning to pH 1.8. A described model for the acid-responsive assembly of fibrils of WPC was proposed. The fibrils went through formation-depolymerization-reformation by weaker noncovalent interactions (surface hydrophobicity) as pH changed from 1.8 to 6.5 back to 1.8. However, the fibrils lost the acid-responsive properties because much more S-S (disulfide) formation occurred when the solution was adjusted to pH 6.5 and reheated. Meanwhile, fibrils still possessed acid-responsive properties when reheated at pH 1.8, and the content of fibrils slightly increased with a further reduction of α-helix structure. PMID:27265171

  6. Ascorbic acid attenuates the pressor response to voluntary apnea in postmenopausal women

    PubMed Central

    Randolph, Brittney J; Patel, Hardikkumar M; Muller, Matthew D

    2015-01-01

    We recently demonstrated that postmenopausal women have an augmented blood pressure response to voluntary apnea compared to premenopausal women. Both obstructive sleep apnea (OSA) and healthy aging are associated with increased oxidative stress, which may impair cardiovascular function. Restoring physiological responses could have clinical relevance since transient surges in blood pressure are thought to be an important stimulus for end-organ damage in aging and disease. We tested the hypothesis that acute antioxidant infusion improves physiological responses to voluntary apnea in healthy postmenopausal women (n = 8, 64 ± 2 year). We measured beat-by-beat mean arterial pressure (MAP), heart rate (HR), and brachial artery blood flow velocity (BBFV, Doppler ultrasound) following intravenous infusion of normal saline and ascorbic acid (∼3500 mg). Subjects performed maximal voluntary end-expiratory apneas and changes (Δ) from baseline were compared between infusions. The breath hold duration and oxygen saturation nadir were similar between saline (29 ± 6 sec, 94 ± 1%) and ascorbic acid (29 ± 5 sec, 94 ± 1%). Ascorbic acid attenuated the pressor response to voluntary apnea (ΔMAP: 6 ± 2 mmHg) as compared to saline (ΔMAP: 12 ± 2 mmHg, P = 0.034) and also attenuated forearm vasoconstriction (ΔBBFV: 4 ± 9 vs. −12 ± 7%, P = 0.049) but did not affect ΔHR. We conclude that ascorbic acid lowers the blood pressure response to voluntary apnea in postmenopausal women by inhibiting vasoconstriction in the limb vasculature. Whether ascorbic acid has similar effects in OSA patients remains to be prospectively tested. PMID:25907792

  7. Change in the plasmid copy number in acetic acid bacteria in response to growth phase and acetic acid concentration.

    PubMed

    Akasaka, Naoki; Astuti, Wiwik; Ishii, Yuri; Hidese, Ryota; Sakoda, Hisao; Fujiwara, Shinsuke

    2015-06-01

    Plasmids pGE1 (2.5 kb), pGE2 (7.2 kb), and pGE3 (5.5 kb) were isolated from Gluconacetobacter europaeus KGMA0119, and sequence analyses revealed they harbored 3, 8, and 4 genes, respectively. Plasmid copy numbers (PCNs) were determined by real-time quantitative PCR at different stages of bacterial growth. When KGMA0119 was cultured in medium containing 0.4% ethanol and 0.5% acetic acid, PCN of pGE1 increased from 7 copies/genome in the logarithmic phase to a maximum of 12 copies/genome at the beginning of the stationary phase, before decreasing to 4 copies/genome in the late stationary phase. PCNs for pGE2 and pGE3 were maintained at 1-3 copies/genome during all phases of growth. Under a higher concentration of ethanol (3.2%) the PCN for pGE1 was slightly lower in all the growth stages, and those of pGE2 and pGE3 were unchanged. In the presence of 1.0% acetic acid, PCNs were higher for pGE1 (10 copies/genome) and pGE3 (6 copies/genome) during the logarithmic phase. Numbers for pGE2 did not change, indicating that pGE1 and pGE3 increase their PCNs in response to acetic acid. Plasmids pBE2 and pBE3 were constructed by ligating linearized pGE2 and pGE3 into pBR322. Both plasmids were replicable in Escherichia coli, Acetobacter pasteurianus and G. europaeus, highlighting their suitability as vectors for acetic acid bacteria. PMID:25575969

  8. Response of the hammerhead shark olfactory epithelium to amino acid stimuli.

    PubMed

    Tricas, Timothy C; Kajiura, Stephen M; Summers, Adam P

    2009-10-01

    Sharks and rays are highly sensitive to chemical stimuli in their natural environment but several hypotheses predict that hammerhead sharks, with their expanded head and enlarged olfactory epithelium, have particularly acute olfactory systems. We used the electro-olfactogram (EOG) technique to compare the relative response of the scalloped hammerhead shark (Sphyrna lewini) olfactory epithelium to 20 proteinogenic amino acids and determine the sensitivity for 6 amino acids. At micromolar concentrations, cysteine evoked the greatest EOG response which was approximately twice as large as that of alanine. The weakest response was obtained for proline followed by aspartic acid and isoleucine. The olfactory epithelium showed adaptation to sequential stimulation, and recovery was related to the inter-stimulus time period. Estimated EOG response thresholds were in the sub-nanomolar range for both alanine (9.2 x 10(-11) M) and cysteine (8.4 x 10(-10) M) and in the micromolar range for proline and serine. These thresholds from 10(-10) to 10(-6) M for the scalloped hammerhead shark are comparable or lower than those reported for other teleost and elasmobranch species. Future work should focus on binary and more complex compounds to test for competition and cross-adaptation for different classes of peripheral receptors, and their responses to molecules found in biologically relevant stimuli. PMID:19711087

  9. Retinoid X receptor and retinoic acid response in the marine sponge Suberites domuncula.

    PubMed

    Wiens, Matthias; Batel, Renato; Korzhev, Michael; Müller, Werner E G

    2003-09-01

    To date no nuclear receptors have been identified or cloned from the phylogenetically oldest metazoan phylum, the Porifera (sponges). We show that retinoic acid causes tissue regression in intact individuals of the demosponge Suberites domuncula and in primmorphs, special three-dimensional cell aggregates. Primmorphs were cultivated on a galectin/poly-L-lysine matrix in order to induce canal formation. In the presence of 1 or 50 micromol l(-1) retinoic acid these canals undergo regression, a process that is reversible. We also cloned the cDNA from S. domuncula encoding the retinoid X receptor (RXR), which displays the two motifs of nuclear hormone receptors, the ligand-binding and the DNA-binding domains, and performed phylogenetic analyses of this receptor. RXR expression undergoes strong upregulation in response to treatment with retinoic acid, whereas the expression of the sponge caspase is not increased. The gene encoding the LIM homeodomain protein was found to be strongly upregulated in response to retinoic acid treatment. These data indicate that the RXR and its ligand retinoic acid play a role in the control of morphogenetic events in sponges. PMID:12909707

  10. Lipid binding protein response to a bile acid library: a combined NMR and statistical approach.

    PubMed

    Tomaselli, Simona; Pagano, Katiuscia; Boulton, Stephen; Zanzoni, Serena; Melacini, Giuseppe; Molinari, Henriette; Ragona, Laura

    2015-11-01

    Primary bile acids, differing in hydroxylation pattern, are synthesized from cholesterol in the liver and, once formed, can undergo extensive enzyme-catalysed glycine/taurine conjugation, giving rise to a complex mixture, the bile acid pool. Composition and concentration of the bile acid pool may be altered in diseases, posing a general question on the response of the carrier (bile acid binding protein) to the binding of ligands with different hydrophobic and steric profiles. A collection of NMR experiments (H/D exchange, HET-SOFAST, ePHOGSY NOESY/ROESY and (15) N relaxation measurements) was thus performed on apo and five different holo proteins, to monitor the binding pocket accessibility and dynamics. The ensemble of obtained data could be rationalized by a statistical approach, based on chemical shift covariance analysis, in terms of residue-specific correlations and collective protein response to ligand binding. The results indicate that the same residues are influenced by diverse chemical stresses: ligand binding always induces silencing of motions at the protein portal with a concomitant conformational rearrangement of a network of residues, located at the protein anti-portal region. This network of amino acids, which do not belong to the binding site, forms a contiguous surface, sensing the presence of the bound lipids, with a signalling role in switching protein-membrane interactions on and off. PMID:26260520

  11. Epoxygenase metabolites of arachidonic acid inhibit vasopressin response in toad bladder

    SciTech Connect

    Schlondorff, D.; Petty, E.; Oates, J.A.; Jacoby, M.; Levine, S.D. Vanderbilt Univ., Nashville, TN )

    1987-09-01

    In addition to cyclooxygenase and lipoxygenase pathways, the kidney can also metabolize arachidonic acid by a NADPH-dependent cytochrome P-450 enzyme to epoxyeicosatrienoic acids (EETs); furthermore, 5,6-EET has been shown to alter electrolyte transport across isolated renal tubules. The authors examined the effects of three ({sup 14}C-labeled)-EETs (5,6-, 11,12-, and 14,15-EET) on osmotic water flow across toad urinary bladder. All three EETs reversibly inhibited vasopressin-stimulated osmotic water flow with 5,6- and 11,12-EET being the most potent. The effects appeared to be independent of prostaglandins EETs inhibited the water flow response to forskolin but not the response to adenosine 3{prime},5{prime}-cyclic monophosphate (cAMP) or 8-BrcAMP, consistent with an effect on cAMP generation. To determine whether these effects were due to the EETs or to products of their metabolism, they examined the effects of their vicinal diol hydrolysis products, the dihydroxyeicosatrienoic acids. Nonenzymatic conversion of labeled 5,6-EET to its vicinal diol occurred rapidly in the buffer, whereas 11,12-EET was hydrolyzed in a saturable manner only when incubated in the presence of bladder tissue. The dihydroxyeicosatrienoic acids formed inhibited water flow in a manner paralleling that of the EETs. The data support the hypothesis that EETs and their physiologically active dihydroxyeicosatrienoic acid metabolites inhibit vasopressin-stimulated water flow predominantly via inhibition of adenylate cyclase.

  12. Genetic selection for modulators of a retinoic-acid-responsive reporter in human cells.

    PubMed Central

    Richards, Burt; Karpilow, Jon; Dunn, Christine; Peterson, Isaac; Maxfield, Andrew; Zharkikh, Ludmilla; Abedi, Majid; Hurlburt, Anthony; Hardman, Joshua; Hsu, Forrest; Li, Wenhua; Rebentisch, Matthew; Sandrock, Robert; Sandrock, Tanya; Kamb, Alexander; Teng, David H-F

    2003-01-01

    We used a genetic screening methodology, a human cell line bearing a retinoic-acid-responsive enhanced GFP reporter, and a flow sorter to recover dominant modulators of reporter expression. Four inducers and three suppressors that were fused to the C terminus of a protein scaffold for stability were isolated and their mechanisms of action studied. Mutagenesis experiments indicated that six of these dominant agents exerted their effects at the protein level. The single cDNA coding fragment that was isolated comprised the central 64-amino-acid section of human cyclophilin B, which contained its peptidyl-prolyl isomerase domain; this cyclophilin fragment repressed expression of the retinoic-acid-responsive reporter. The remaining clones encoded peptides shorter than 30 amino acids unrelated to known gene open reading frames. Genetic epistasis studies between the strongest inducer, R3, and a dominant-negative mutant of RARalpha suggest that the two factors function in the same pathway. Transcript microarray analyses suggest that R3 induced a subset of the retinoid-responsive genes in melanoma cells. Finally, yeast two-hybrid assays and co-immunoprecipitation studies of human cell extracts identified PAT1 as a protein that interacts with R3. PMID:12663543

  13. Diagnosis and management of cerebral folate deficiency. A form of folinic acid-responsive seizures.

    PubMed

    Al-Baradie, Raidah S; Chaudhary, Mohammed W

    2014-10-01

    Folinic acid-responsive seizures (FARS) are a rare treatable cause of neonatal epilepsy. They have characteristic peaks on CSF monoamine metabolite analysis, and have mutations in the ALDH7A1 gene, characteristically found in pyridoxine-dependent epilepsy. There are case reports of patients presenting with seizures at a later age, and with folate deficiency due to different mechanisms with variable response to folinic acid supplementation. Here, we report 2 siblings who presented with global developmental delay and intractable seizures who responded clinically to folinic acid therapy. Their work-up included metabolic and genetic testing. The DNA sequencing was carried out for the ALDH7A1 gene, and the folate receptor 1 (FOLR1) gene. They had very low 5-methyltetrahydrofolate (5-MTHF) in CSF with no systemic folate deficiency and no characteristic peaks on neurotransmitter metabolite chromatogram. A novel mutation in the FOLR1 gene was found. The mutation in this gene is shown to affect CSF folate transport leading to cerebral folate deficiency. The response to treatment with folinic acid was dramatic with improvement in social interaction, mobility, and complete seizure control. We should consider the possibility of this treatable condition in appropriate clinical circumstances early, as diagnosis with favorable outcome depends on the specialized tests. PMID:25274592

  14. Physiological responses of root-less epiphytic plants to acid rain.

    PubMed

    Kováčik, Jozef; Klejdus, Bořivoj; Bačkor, Martin; Stork, František; Hedbavny, Josef

    2011-03-01

    Selected physiological responses of Tillandsia albida (Bromeliaceae) and two lichens (Hypogymnia physodes and Xanthoria parietina) exposed to simulated acid rain (AR) over 3 months were studied. Pigments were depressed in all species being affected the most in Tillandsia. Amounts of hydrogen peroxide and superoxide were elevated and soluble proteins decreased only in AR-exposed Hypogymnia. Free amino acids were slightly affected among species and only glutamate sharply decreased in AR-exposed Xanthoria. Slight increase in soluble phenols but decrease in flavonoids in almost all species suggests that the latter are not essential for tolerance to AR. Almost all phenolic acids in Tillandsia leaves decreased in response to AR and activities of selected enzymes (phenylalanine ammonia-lyase, polyphenol oxidase, ascorbate- and guaiacol-peroxidase) were enhanced by AR. In lichens, considerable increase in metabolites (physodalic acid, atranorin and parietin) in response to AR was found but amount of ergosterol was unchanged. Macronutrients (K, Ca, Mg) decreased more pronouncedly in comparison with micronutrients in all species. Xanthoria showed higher tolerance in comparison with Hypogymnia, suggesting that could be useful for long-term biomonitoring. PMID:21161375

  15. Translation quality control is critical for bacterial responses to amino acid stress

    PubMed Central

    Bullwinkle, Tammy J.; Ibba, Michael

    2016-01-01

    Gene expression relies on quality control for accurate transmission of genetic information. One mechanism that prevents amino acid misincorporation errors during translation is editing of misacylated tRNAs by aminoacyl-tRNA synthetases. In the absence of editing, growth is limited upon exposure to excess noncognate amino acid substrates and other stresses, but whether these physiological effects result solely from mistranslation remains unclear. To explore if translation quality control influences cellular processes other than protein synthesis, an Escherichia coli strain defective in Tyr-tRNAPhe editing was used. In the absence of editing, cellular levels of aminoacylated tRNAPhe were elevated during amino acid stress, whereas in the wild-type strain these levels declined under the same growth conditions. In the editing-defective strain, increased levels of aminoacylated tRNAPhe led to continued synthesis of the PheL leader peptide and attenuation of pheA transcription under amino acid stress. Consequently, in the absence of editing, activation of the phenylalanine biosynthetic operon becomes less responsive to phenylalanine limitation. In addition to raising aminoacylated tRNA levels, the absence of editing lowered the amount of deacylated tRNAPhe in the cell. This reduction in deacylated tRNA was accompanied by decreased synthesis of the second messenger guanosine tetraphosphate and limited induction of stringent response-dependent gene expression in editing-defective cells during amino acid stress. These data show that a single quality-control mechanism, the editing of misacylated aminoacyl-tRNAs, provides a critical checkpoint both for maintaining the accuracy of translation and for determining the sensitivity of transcriptional responses to amino acid stress. PMID:26858451

  16. Effects of Diets High in Unsaturated Fatty Acids on Socially Induced Stress Responses in Guinea Pigs

    PubMed Central

    Nemeth, Matthias; Millesi, Eva; Wagner, Karl-Heinz; Wallner, Bernard

    2014-01-01

    Unsaturated fatty acids (UFAs), such as omega-3 and omega-6 poly- and omega-9 monounsaturated fatty acids are important nutrients and major components of neuronal cell membranes. They play a major role in modulating brain functions and physiology and may therefore diminish behavioral and physiological stress reactions in corroboration with decreased cortisol concentrations. Functionally, cortisol itself can modulate several behaviors and also the fatty acid metabolism in the long term. But only little is known about the behavioral and physiological influences of dietary UFAs in a social group, where individuals are regularly exposed to stressful situations. Therefore, the aim of this study was to determine the effects of dietary UFAs on saliva cortisol concentrations and behavioral responses in socially confronted guinea pigs. Three groups of animals were additionally supplemented with 500 mg chia seeds (high in omega-3), walnuts (high in omega-6), or peanuts (high in omega-9) per kg bodyweight each day and compared to a control group. During social confrontation saliva cortisol concentrations significantly increased in all groups, which was accompanied by a loss in bodyweight. However, cortisol levels remained lower in the chia and walnut groups compared to controls. Additionally, the walnut group displayed significantly increased locomotion, while no differences between groups were detected in socio-positive, sexual, or aggressive behaviors. Total plasma omega-3, omega-6, and omega-9 fatty acids were significantly increased in the corresponding groups, due to the dietary supplementations. However, a significant decrease in plasma omega-3 and an increase in plasma n-6 fatty acids were detected in the chia group when comparing the measurements before and after social confrontation. We conclude that both omega-3 and omega-6 polyunsaturated fatty acids can diminish behavioral and physiological stress responses to the social environment, enabling individuals to cope

  17. Antioxidant response of soybean seedlings to joint stress of lanthanum and acid rain.

    PubMed

    Liang, Chanjuan; Wang, Weimin

    2013-11-01

    Excess of rare earth elements in soil can be a serious environmental stress on plants, in particular when acid rain coexists. To understand how such a stress affects plants, we studied antioxidant response of soybean leaves and roots exposed to lanthanum (0.06, 0.18, and 0.85 mmol L(-1)) under acid rain conditions (pH 4.5 and 3.0). We found that low concentration of La3+ (0.06 mmol L(-1)) did not affect the activity of antioxidant enzymes (catalase and peroxidase) whereas high concentration of La3+ (≥0.18 mmol L(-1)) did. Compared to treatment with acid rain (pH 4.5 and pH 3.0) or La3+ alone, joint stress of La3+ and acid rain affected more severely the activity of catalase and peroxidase, and induced more H2O2 accumulation and lipid peroxidation. When treated with high level of La3+ (0.85 mmol L(-1)) alone or with acid rain (pH 4.5 and 3.0), roots were more affected than leaves regarding the inhibition of antioxidant enzymes, physiological function, and growth. The severity of oxidative damage and inhibition of growth caused by the joint stress associated positively with La3+ concentration and soil acidity. These results will help us understand plant response to joint stress, recognize the adverse environmental impact of rare earth elements in acidic soil, and develop measures to eliminate damage caused by such joint stress. PMID:23653318

  18. Effects of diets high in unsaturated Fatty acids on socially induced stress responses in Guinea pigs.

    PubMed

    Nemeth, Matthias; Millesi, Eva; Wagner, Karl-Heinz; Wallner, Bernard

    2014-01-01

    Unsaturated fatty acids (UFAs), such as omega-3 and omega-6 poly- and omega-9 monounsaturated fatty acids are important nutrients and major components of neuronal cell membranes. They play a major role in modulating brain functions and physiology and may therefore diminish behavioral and physiological stress reactions in corroboration with decreased cortisol concentrations. Functionally, cortisol itself can modulate several behaviors and also the fatty acid metabolism in the long term. But only little is known about the behavioral and physiological influences of dietary UFAs in a social group, where individuals are regularly exposed to stressful situations. Therefore, the aim of this study was to determine the effects of dietary UFAs on saliva cortisol concentrations and behavioral responses in socially confronted guinea pigs. Three groups of animals were additionally supplemented with 500 mg chia seeds (high in omega-3), walnuts (high in omega-6), or peanuts (high in omega-9) per kg bodyweight each day and compared to a control group. During social confrontation saliva cortisol concentrations significantly increased in all groups, which was accompanied by a loss in bodyweight. However, cortisol levels remained lower in the chia and walnut groups compared to controls. Additionally, the walnut group displayed significantly increased locomotion, while no differences between groups were detected in socio-positive, sexual, or aggressive behaviors. Total plasma omega-3, omega-6, and omega-9 fatty acids were significantly increased in the corresponding groups, due to the dietary supplementations. However, a significant decrease in plasma omega-3 and an increase in plasma n-6 fatty acids were detected in the chia group when comparing the measurements before and after social confrontation. We conclude that both omega-3 and omega-6 polyunsaturated fatty acids can diminish behavioral and physiological stress responses to the social environment, enabling individuals to cope

  19. Ciliary subcellular localization of TGR5 determines the cholangiocyte functional response to bile acid signaling

    PubMed Central

    Masyuk, Anatoliy I.; Huang, Bing Q.; Radtke, Brynn N.; Gajdos, Gabriella B.; Splinter, Patrick L.; Masyuk, Tatyana V.; Gradilone, Sergio A.

    2013-01-01

    TGR5, the G protein-coupled bile acid receptor that transmits bile acid signaling into a cell functional response via the intracellular cAMP signaling pathway, is expressed in human and rodent cholangiocytes. However, detailed information on the localization and function of cholangiocyte TGR5 is limited. We demonstrated that in human (H69 cells) and rat cholangiocytes, TGR5 is localized to multiple, diverse subcellular compartments, with its strongest expression on the apical plasma, ciliary, and nuclear membranes. To evaluate the relationship between ciliary TGR5 and the cholangiocyte functional response to bile acid signaling, we used a model of ciliated and nonciliated H69 cells and demonstrated that TGR5 agonists induce opposite changes in cAMP and ERK levels in cells with and without primary cilia. The cAMP level was increased in nonciliated cholangiocytes but decreased in ciliated cells. In contrast, ERK signaling was induced in ciliated cholangiocytes but suppressed in cells without cilia. TGR5 agonists inhibited proliferation of ciliated cholangiocytes but activated proliferation of nonciliated cells. The observed differential effects of TGR5 agonists were associated with the coupling of TGR5 to Gαi protein in ciliated cells and Gαs protein in nonciliated cholangiocytes. The functional responses of nonciliated and ciliated cholangiocytes to TGR5-mediated bile acid signaling may have important pathophysiological significance in cilia-related liver disorders (i.e., cholangiociliopathies), such as polycystic liver disease. In summary, TGR5 is expressed on diverse cholangiocyte compartments, including a primary cilium, and its ciliary localization determines the cholangiocyte functional response to bile acid signaling. PMID:23578785

  20. Ciliary subcellular localization of TGR5 determines the cholangiocyte functional response to bile acid signaling.

    PubMed

    Masyuk, Anatoliy I; Huang, Bing Q; Radtke, Brynn N; Gajdos, Gabriella B; Splinter, Patrick L; Masyuk, Tatyana V; Gradilone, Sergio A; LaRusso, Nicholas F

    2013-06-01

    TGR5, the G protein-coupled bile acid receptor that transmits bile acid signaling into a cell functional response via the intracellular cAMP signaling pathway, is expressed in human and rodent cholangiocytes. However, detailed information on the localization and function of cholangiocyte TGR5 is limited. We demonstrated that in human (H69 cells) and rat cholangiocytes, TGR5 is localized to multiple, diverse subcellular compartments, with its strongest expression on the apical plasma, ciliary, and nuclear membranes. To evaluate the relationship between ciliary TGR5 and the cholangiocyte functional response to bile acid signaling, we used a model of ciliated and nonciliated H69 cells and demonstrated that TGR5 agonists induce opposite changes in cAMP and ERK levels in cells with and without primary cilia. The cAMP level was increased in nonciliated cholangiocytes but decreased in ciliated cells. In contrast, ERK signaling was induced in ciliated cholangiocytes but suppressed in cells without cilia. TGR5 agonists inhibited proliferation of ciliated cholangiocytes but activated proliferation of nonciliated cells. The observed differential effects of TGR5 agonists were associated with the coupling of TGR5 to Gαi protein in ciliated cells and Gαs protein in nonciliated cholangiocytes. The functional responses of nonciliated and ciliated cholangiocytes to TGR5-mediated bile acid signaling may have important pathophysiological significance in cilia-related liver disorders (i.e., cholangiociliopathies), such as polycystic liver disease. In summary, TGR5 is expressed on diverse cholangiocyte compartments, including a primary cilium, and its ciliary localization determines the cholangiocyte functional response to bile acid signaling. PMID:23578785

  1. Functional convergence of oxylipin and abscisic acid pathways controls stomatal closure in response to drought.

    PubMed

    Savchenko, Tatyana; Kolla, Venkat A; Wang, Chang-Quan; Nasafi, Zainab; Hicks, Derrick R; Phadungchob, Bpantamars; Chehab, Wassim E; Brandizzi, Federica; Froehlich, John; Dehesh, Katayoon

    2014-03-01

    Membranes are primary sites of perception of environmental stimuli. Polyunsaturated fatty acids are major structural constituents of membranes that also function as modulators of a multitude of signal transduction pathways evoked by environmental stimuli. Different stresses induce production of a distinct blend of oxygenated polyunsaturated fatty acids, "oxylipins." We employed three Arabidopsis (Arabidopsis thaliana) ecotypes to examine the oxylipin signature in response to specific stresses and determined that wounding and drought differentially alter oxylipin profiles, particularly the allene oxide synthase branch of the oxylipin pathway, responsible for production of jasmonic acid (JA) and its precursor 12-oxo-phytodienoic acid (12-OPDA). Specifically, wounding induced both 12-OPDA and JA levels, whereas drought induced only the precursor 12-OPDA. Levels of the classical stress phytohormone abscisic acid (ABA) were also mainly enhanced by drought and little by wounding. To explore the role of 12-OPDA in plant drought responses, we generated a range of transgenic lines and exploited the existing mutant plants that differ in their levels of stress-inducible 12-OPDA but display similar ABA levels. The plants producing higher 12-OPDA levels exhibited enhanced drought tolerance and reduced stomatal aperture. Furthermore, exogenously applied ABA and 12-OPDA, individually or combined, promote stomatal closure of ABA and allene oxide synthase biosynthetic mutants, albeit most effectively when combined. Using tomato (Solanum lycopersicum) and Brassica napus verified the potency of this combination in inducing stomatal closure in plants other than Arabidopsis. These data have identified drought as a stress signal that uncouples the conversion of 12-OPDA to JA and have revealed 12-OPDA as a drought-responsive regulator of stomatal closure functioning most effectively together with ABA. PMID:24429214

  2. The Staphylococcus aureus Response to Unsaturated Long Chain Free Fatty Acids: Survival Mechanisms and Virulence Implications

    PubMed Central

    Kenny, John G.; Ward, Deborah; Josefsson, Elisabet; Jonsson, Ing-Marie; Hinds, Jason; Rees, Huw H.; Lindsay, Jodi A.; Tarkowski, Andrej; Horsburgh, Malcolm J.

    2009-01-01

    Staphylococcus aureus is an important human commensal and opportunistic pathogen responsible for a wide range of infections. Long chain unsaturated free fatty acids represent a barrier to colonisation and infection by S. aureus and act as an antimicrobial component of the innate immune system where they are found on epithelial surfaces and in abscesses. Despite many contradictory reports, the precise anti-staphylococcal mode of action of free fatty acids remains undetermined. In this study, transcriptional (microarrays and qRT-PCR) and translational (proteomics) analyses were applied to ascertain the response of S. aureus to a range of free fatty acids. An increase in expression of the σB and CtsR stress response regulons was observed. This included increased expression of genes associated with staphyloxanthin synthesis, which has been linked to membrane stabilisation. Similarly, up-regulation of genes involved in capsule formation was recorded as were significant changes in the expression of genes associated with peptidoglycan synthesis and regulation. Overall, alterations were recorded predominantly in pathways involved in cellular energetics. In addition, sensitivity to linoleic acid of a range of defined (sigB, arcA, sasF, sarA, agr, crtM) and transposon-derived mutants (vraE, SAR2632) was determined. Taken together, these data indicate a common mode of action for long chain unsaturated fatty acids that involves disruption of the cell membrane, leading to interference with energy production within the bacterial cell. Contrary to data reported for other strains, the clinically important EMRSA-16 strain MRSA252 used in this study showed an increase in expression of the important virulence regulator RNAIII following all of the treatment conditions tested. An adaptive response by S. aureus of reducing cell surface hydrophobicity was also observed. Two fatty acid sensitive mutants created during this study were also shown to diplay altered pathogenesis as assessed

  3. Blunted Behavioral and C Fos Responses to Acidic Fumes in the African Naked Mole-Rat

    PubMed Central

    LaVinka, Pamela Colleen; Park, Thomas J.

    2012-01-01

    Acidosis in the skin triggers activation of pain pathways and behaviors indicative of pain in vertebrates. The exception is the naked mole-rat, the only known vertebrate to show physiological and behavioral insensitivity to acid pain in the skin. The goal of the present study was to determine behavioral and physiological responses of this species to airborne acidic fumes, which would be expected to affect the trigeminal pain pathway in other species. Behaviorally, naked mole-rats did not avoid fumes from moderately high concentrations of acetic acid (10 and 20%), and c Fos labeling showed no increase in activity in the trigeminal nuclei and nucleus tractus solitarius. In contrast, these concentrations triggered behavioral aversion and increased Fos activity in other laboratory rodents. For a very high concentration of acetic acid (50%), naked mole-rats showed significant avoidance behavior and increased Fos labeling in the nucleus tractus solitarius caudal region, which receives vagal chemosensory information. However, there was no increase in trigeminal labeling, and in fact, activity significantly decreased. This pattern is opposite of that associated with another irritant, ammonia fumes, which elicited an increase in trigeminal but not nucleus tractus solitarius Fos labeling, and no behavioral avoidance. Behavioral avoidance of acidic fumes, but no increased labeling in the trigeminal pain nucleus is consistent with the notion of adaptations to blunt acid pain, which would be advantageous for naked mole-rats as they normally live under chronically high levels of acidosis-inducing CO2. PMID:23028761

  4. Human sweat and 2-oxopentanoic acid elicit a landing response from Anopheles gambiae.

    PubMed

    Healy, T P; Copland, M J

    2000-06-01

    A wind tunnel bioassay and video to observe mosquitoes landing on heated glass cylinders were used to test sweat and some derivatives for responses of Anopheles gambiae Giles (Diptera: Culicidae), a highly anthropophilic African species of malaria vector. Filter papers impregnated with human sweat and a diethyl ether extract from the filter papers elicited significantly more landings than a water control (P<0.001). The concentration of lactic acid in the extract was determined by GLC assay, but bioassays of an equivalent dose of lactic acid (from a commercial supplier) did not elicit landings. Chemical analysis of the extract by combined GLC/mass spectrometry indicated the presence of 73 compounds, of which 40 were tentatively identified. The major components of the extract were aliphatic carboxylic acids. An artificial blend of 22 carboxylic acids did not elicit landings. Bioassays of 2-oxopentanoic acid elicited significantly more, landings (P<0.001). The possible importance of oxo-carboxylic acids for host-seeking by anthropophilic mosquitoes is discussed and their use for trapping is suggested. PMID:10872864

  5. Temperature and magnetic field responsive hyaluronic acid particles with tunable physical and chemical properties

    NASA Astrophysics Data System (ADS)

    Ekici, Sema; Ilgin, Pinar; Yilmaz, Selahattin; Aktas, Nahit; Sahiner, Nurettin

    2011-01-01

    We report the preparation and characterization of thiolated-temperature-responsive hyaluronic acid-cysteamine-N-isopropyl acrylamide (HA-CYs-NIPAm) particles and thiolated-magnetic-responsive hyaluronic acid (HA-Fe-CYs) particles. Linear hyaluronic acid (HA) crosslinked with divinyl sulfone as HA particles was prepared using a water-in-oil micro emulsion system which were then oxidized HA-O with NaIO4 to develop aldehyde groups on the particle surface. HA-O hydrogel particles were then reacted with cysteamine (CYs) which interacted with aldehydes on the HA surface to form HA particles with cysteamine (HA-CYs) functionality on the surface. HA-CYs particles were further exposed to radical polymerization with NIPAm to obtain temperature responsive HA-CYs-NIPAm hydrogel particles. To acquire magnetic field responsive HA composites, magnetic iron particles were included in HA to form HA-Fe during HA particle preparation. HA-Fe hydrogel particles were also chemically modified. The prepared HA-CYs-NIPAm demonstrated temperature dependent size variations and phase transition temperature. HA-CYs-NIPAm and HA-Fe-CYs particles can be used as drug delivery vehicles. Sulfamethoxazole (SMZ), an antibacterial drug, was used as a model drug for temperature-induced release studies from these particles.

  6. Dietary fatty acid modulation of mucosally-induced tolerogenic immune responses.

    PubMed

    Harbige, L S; Fisher, B A

    2001-11-01

    Immunological unresponsiveness or hyporesponsiveness (tolerance) can be induced by feeding protein antigens to naive animals. Using a classical oral ovalbumin gut-induced tolerance protocol in BALB/c mice we investigated the effects of dietary n-6 and n-3 polyunsaturated fatty acids (PUFA) on high-and low-dose oral tolerance (and in non-tolerised animals, i.e. effects of antigen challenge alone) in relation to lymphoproliferative, cytokine and antibody responses. Fish oil rich in long-chain n-3 fatty acids decreased both T-helper (Th) 1- and Th2-like responses. In contrast, borage (Borago officinalis) oil rich in n-6 PUFA, of which gamma-linolenic acid is rapidly metabolised to longer-chain n-6 PUFA, increased Thl-like responses and decreased Th2-like responses, and possibly enhanced suppressor cell or Th3-like activity. These findings are in general agreement with other studies on the effects of long chain n-3 PUFA on immune system functions, and characterise important differences between long-chain n-3 and n-6 PUFA, defining more precisely and broadly the immunological regulatory mechanisms involved. They are also discussed in relation to autoimmune disease. PMID:12069397

  7. Characterization of a retinoic acid responsive element isolated by whole genome PCR.

    PubMed Central

    Costa-Giomi, M P; Gaub, M P; Chambon, P; Abarzúa, P

    1992-01-01

    We have used whole PCR in an attempt to isolate novel retinoic acid (RA) responsive genes. We cloned several small genomic fragments from total human DNA containing putative retinoic acid responsive elements (RAREs) selected by direct binding to the retinoic acid receptor alpha (RAR alpha). We report here that an oligonucleotide containing a sequence from one of the cloned human DNA fragments, and referred to as alpha 1, functions as an authentic RARE. It is shown that both RAR alpha and RAR beta produced in Cos cells as well as in vitro translated RAR alpha bind directly and sequence-specifically to the alpha 1RARE. By mutational analysis it is demonstrated that the alpha 1RARE consists of an imperfect direct repeat of the estrogen- and thyroid hormone-related AGGTCA half-site motif separated by a 5 bp spacer. The orientation and spacing of the half-site repeats are shown to play a critical role in RAR recognition. When cloned upstream of a TK-Luc reporter, the alpha 1RARE is shown to confer responsiveness to RA in an orientation-independent fashion in F9 and CV-1 cells. The magnitude of the RA response mediated by the alpha 1RARE differed in these cell lines. Images PMID:1320257

  8. Lipid metabolic dose response to dietary alpha-linolenic acid in monk parrot (Myiopsitta monachus).

    PubMed

    Petzinger, Christina; Heatley, J J; Bailey, Christopher A; Bauer, John E

    2014-03-01

    Monk parrots (Myiopsitta monachus) are susceptible to atherosclerosis, a progressive disease characterized by the formation of plaques in the arteries accompanied by underlying chronic inflammation. The family of n-3 fatty acids, especially eicosapentaenoic acid (20:5n-3, EPA) and docosahexaenoic acid (22:6n-3, DHA), have consistently been shown to reduce atherosclerotic risk factors in humans and other mammals. Some avian species have been observed to convert α-linolenic acid (18:3n-3, ALA) to EPA and DHA (Htin et al. in Arch Geflugelk 71:258-266, 2007; Petzinger et al. in J Anim Physiol Anim Nutr, 2013). Therefore, the metabolic effects of including flaxseed oil, as a source of ALA, in the diet at three different levels (low, medium, and high) on the lipid metabolism of Monk parrots was evaluated through measuring plasma total cholesterol (TC), free cholesterol (FC), triacylglycerols (TAG), and phospholipid fatty acids. Feed intake, body weight, and body condition score were also assessed. Thus the dose and possible saturation response of increasing dietary ALA at constant linoleic acid (18:2n-6, LNA) concentration on lipid metabolism in Monk parrots (M. monachus) was evaluated. Calculated esterified cholesterol in addition to plasma TC, FC, and TAG were unaltered by increasing dietary ALA. The high ALA group had elevated levels of plasma phospholipid ALA, EPA, and docosapentaenoic acid (DPAn-3, 22:5n-3). The medium and high ALA groups had suppressed plasma phospholipid 20:2n-6 and adrenic acid (22:4n-6, ADA) compared to the low ALA group. When the present data were combined with data from a previous study (Petzinger et al. in J Anim Physiol Anim Nutr, 2013) a dose response to dietary ALA was observed when LNA was constant. Plasma phospholipid ALA, EPA, DPAn-3, DHA, and total n-3 were positively correlated while 20:2n-6, di-homo-gamma-linoleic acid (20:3n-6Δ7), arachidonic acid (20:4n-6), ADA, and total n-6 were inversely correlated with dietary en% ALA. PMID

  9. In Vitro Cytotoxicity and Adaptive Stress Responses to Selected Haloacetic Acid and Halobenzoquinone Water Disinfection Byproducts.

    PubMed

    Procházka, Erik; Escher, Beate I; Plewa, Michael J; Leusch, Frederic D L

    2015-10-19

    The process of disinfecting drinking water inadvertently leads to the formation of numerous disinfection byproducts (DBPs). Some of these are mutagenic, genotoxic, teratogenic, and cytotoxic, as well as potentially carcinogenic both in vivo and in vitro. We investigated the in vitro biological activity of five DBPs: three monohaloacetic acids (monoHAAs) [chloroacetic acid (CAA), bromoacetic acid (BAA), and iodoacetic acid (IAA)] and two novel halobenzoquinones (HBQs) [2,6-dichloro-p-benzoquinone (DCBQ) and 2,6-dibromo-p-benzoquinone]. We focused particularly on cytotoxicity and induction of two adaptive stress response pathways: the oxidative stress responsive Nrf2/ARE and DNA-damage responsive p53 pathways. All five DBPs were cytotoxic to the Caco-2 cell line after a 4 h exposure, and all DBPs induced both of the adaptive stress response pathways, Nrf2/ARE and p53, in the micromolar range, as measured by two β-lactamase-based reporter gene assays. The decreasing order of potency for all three endpoints for the five DBPs was IAA ∼ BAA > DCBQ ∼ DBBQ > CAA. Induction of oxidative stress was previously proposed to be the molecular initiating event (MIE) for both classes of DBPs. However, comparing the levels of activation of the two pathways uncovered that the Nrf2/ARE pathway was the more sensitive endpoint for HAAs, whereas the p53 pathway was more sensitive in the case of HBQs. Therefore, the DNA damage-responsive p53 pathway may be an important piece of information to fill in a gap in the adverse outcome pathway framework for the assessment of HBQs. Finally, we cautiously compared the potential risk of the two novel HBQs using a benchmarking approach to that of the well-studied CAA, which suggested that their relative risk may be lower than that of BAA and IAA. PMID:26327680

  10. Electro-olfactogram and multiunit olfactory receptor responses to complex mixtures of amino acids in the channel catfish, Ictalurus punctatus.

    PubMed

    Kang, J S; Caprio, J

    1991-10-01

    In vivo electrophysiological recordings from populations of olfactory receptor neurons in the channel catfish, Ictalurus punctatus, clearly showed that both electro-olfactogram and integrated neural responses of olfactory receptor cells to complex mixtures consisting of up to 10 different amino acids were predictable with knowledge of (a) the responses to the individual components in the mixture and (b) the relative independence of the respective receptor sites for the component stimuli. All amino acid stimuli used to form the various mixtures were initially adjusted in concentration to provide approximately equal response magnitudes. Olfactory receptor responses to both multimixtures and binary mixtures were recorded. Multimixtures were formed by mixing equal aliquots of 3-10 different amino acids. Binary mixtures were formed by mixing equal aliquots of two equally stimulatory solutions. Solution 1 contained either one to nine different neutral amino acids with long side-chains (LCNs) or one to five different neutral amino acids with short side-chains (SCNs). Solution 2, comprising the binary mixture, consisted of only a single stimulus, either a LCN, SCN, basic, or acidic amino acid. The increasing magnitude of the olfactory receptor responses to mixtures consisting of an increasing number of neutral amino acids indicated that multiple receptor site types with highly overlapping specificities exist to these compounds. For both binary mixtures and multimixtures composed of neutral and basic or neutral and acidic amino acids, the receptor responses were significantly enhanced compared with those mixtures consisting of an equal number of only neutral amino acids. These results demonstrate that receptor sites for the basic and acidic amino acids, respectively, are highly independent of those for the neutral amino acids, and suggest that a mechanism for synergism is the simultaneous activation of relatively independent receptor sites by the components in the mixture

  11. Effects of simulated acid rain on yield response of two soybean cultivars

    SciTech Connect

    Porter, P.M.; Banwart, W.L.; Hassett, J.J.; Finke, R.L.

    1987-01-01

    Field experiments were conducted for 3 yrs. to determine the effects of simulated acid rain on seed yield of two soybean (Glycine max (L.) Merr.) cultivars, 'Amsoy 71' and 'Williams 82'. Plants were treated biweekly with simulated rain of pH 5.6, 4.6, 4.2, 3.8, 3.4, and 3.0. For Amsoy 71 there was a linear decrease in yield with increasing rainfall acidity for 1 of 3 yrs but no significant effects for the other two. Thus, acid rain appears to reduce the yield of some soybean cultivars slightly, but this effect is not consistent from year to year. Amsoy 71 and Williams 82 soybean treated with the most-acidic rain, pH 3.0, resulted in average yields for the 3 yrs of the study of approximately 3% and 4% lower than the average yields for the other treatments, respectively. However, calculations from the response functions developed have shown that, at current levels of rainfall acidities, the effects on yield are very small. With an increase in rainfall acidity of 50% in Illinois, the predicted yield decrease for Amsoy 71 and Williams 82 soybean would be less than 1%. Similarly, the expected increase in yield of these cultivars would be 1% or less if acidity in the rainfall were reduced by 50%. While there may be beneficial effects of reduced S and N oxide emissions, these results suggest the resultant lower rainfall acidities are not likely to produce noticeable changes in soybean yields.

  12. Dual Enzyme-Responsive Capsules of Hyaluronic Acid-block-Poly(Lactic Acid) for Sensing Bacterial Enzymes.

    PubMed

    Tücking, Katrin-Stephanie; Grützner, Verena; Unger, Ronald E; Schönherr, Holger

    2015-07-01

    The synthesis of novel amphiphilic hyaluronic acid (HYA) and poly(lactic acid) (PLA) block copolymers is reported as the key element of a strategy to detect the presence of pathogenic bacterial enzymes. In addition to the formation of defined HYA-block-PLA assemblies, the encapsulation of fluorescent reporter dyes and the selective enzymatic degradation of the capsules by hyaluronidase and proteinase K are studied. The synthesis of the dual enzyme-responsive HYA-b-PLA is carried out by copper-catalyzed Huisgen 1,3-dipolar cycloaddition. The resulting copolymers are assembled in water to form vesicular structures, which are characterized by scanning electron microscopy, transmission electron microscopy, dynamic light scattering (DLS), and fluorescence lifetime imaging microscopy (FLIM). DLS measurements show that both enzymes cause a rapid decrease in the hydrodynamic diameter of the nanocapsules. Fluorescence spectroscopy data confirm the liberation of encapsulated dye, which indicates the disintegration of the capsules and validates the concept of enzymatically triggered payload release. Finally, cytotoxicity assays confirm that the HYA-b-PLA nanocapsules are biocompatible with primary human dermal microvascular endothelial cells. PMID:25940300

  13. Growth parameter and yield component response of field corn to simulated acid rain

    SciTech Connect

    Banwart, W.L.; Porter, P.M.; Ziegler, E.L.; Hassett, J.J.

    1988-01-01

    Acid rain occurs in the midwest. Studies to date have suggested minimal yield response of field corn to acid rain. However, small but significant reductions in yield have been shown for some cultivars under extreme conditions. To define further these yield changes the study examined the effect of simulated acid rain on parameters associated with corn yield. Cultivars B73 x Mo17 and Pioneer 3377 were shielded from ambient rain by two movable rain exclusion shelters. Six simulated rain treatments were applied biweekly within these shelters through the use of a nozzle distribution system. For the most part, growth and yield parameters were unaffected by simulated rain treatment. While the only significant yield reduction was a contrast of pH 3.0 and the average of all other treatments for B73 x Mo17, the reduction appears to be the result both of slightly fewer ears and slightly less successful ear fill.

  14. Marsh plant response to metals: Exudation of aliphatic low molecular weight organic acids (ALMWOAs)

    NASA Astrophysics Data System (ADS)

    Rocha, A. Cristina S.; Almeida, C. Marisa R.; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

    2016-03-01

    Metal exposure is known to induce the production and secretion of substances, such as aliphatic low molecular weight organic acids (ALMWOAs), into the rhizosphere by plant roots. Knowledge on this matter is extensive for soil plants but still considerably scarce regarding marsh plants roots adapted to high salinity media. Phragmites australis and Halimione portulacoides, two marsh plants commonly distributed in European estuarine salt marshes, were used to assess the response of roots of both species, in terms of ALMWOAs exudation, to Cu, Ni and Cd exposure (isolated and in mixture since in natural environment, they are exposed to mixture of metals). As previous studies were carried out in unrealistic and synthetic media, here a more natural medium was selected. Therefore, in vitro experiments were carried out, with specimens of both marsh plants, and in freshwater contaminated with two different Cu, Ni and Cd concentrations (individual metal and in mixture). Both marsh plants were capable of liberating ALMWOAs into the surrounding medium. Oxalic, citric and maleic acids were found in P. australis root exudate solutions and oxalic and maleic acids in H. portulacoides root exudate solutions. ALMWOA liberation by both plants was plant species and metal-dependent. For instance, Cu affected the exudation of oxalic acid by H. portulacoides and of oxalic and citric acids by P. australis roots. In contrast, Ni and Cd did not stimulate any specific response. Regarding the combination of all metals, H. portulacoides showed a similar response to that observed for Cu individually. However, in the P. australis case, at high metal concentration mixture, a synergetic effect led to the increase of oxalic acid levels in root exudate solution and to a decrease of citric acid liberation. A correlation between ALMWOAs exudation and metal accumulation could not be established. P. australis and H. portulacoides are considered suitable metal phytoremediators of estuarine impacted areas

  15. Response of soil respiration to acid rain in forests of different maturity in southern China.

    PubMed

    Liang, Guohua; Liu, Xingzhao; Chen, Xiaomei; Qiu, Qingyan; Zhang, Deqiang; Chu, Guowei; Liu, Juxiu; Liu, Shizhong; Zhou, Guoyi

    2013-01-01

    The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF), a transitional mixed conifer and broadleaf forest (MF) and an old-growth broadleaved forest (BF)] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR) treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0). Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types. PMID:23626790

  16. Response of Soil Respiration to Acid Rain in Forests of Different Maturity in Southern China

    PubMed Central

    Chen, Xiaomei; Qiu, Qingyan; Zhang, Deqiang; Chu, Guowei; Liu, Juxiu; Liu, Shizhong; Zhou, Guoyi

    2013-01-01

    The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF), a transitional mixed conifer and broadleaf forest (MF) and an old-growth broadleaved forest (BF)] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR) treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0). Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types. PMID:23626790

  17. PTH1 Receptor Is Involved in Mediating Cellular Response to Long-Chain Polyunsaturated Fatty Acids

    PubMed Central

    Chachisvilis, Mirianas

    2012-01-01

    The molecular pathways by which long chain polyunsaturated fatty acids (LCPUFA) influence skeletal health remain elusive. Both LCPUFA and parathyroid hormone type 1 receptor (PTH1R) are known to be involved in bone metabolism while any direct link between the two is yet to be established. Here we report that LCPUFA are capable of direct, PTH1R dependent activation of extracellular ligand-regulated kinases (ERK). From a wide range of fatty acids studied, varying in chain length, saturation, and position of double bonds, eicosapentaenoic (EPA) and docosahexaenoic fatty acids (DHA) caused the highest ERK phosphorylation. Moreover, EPA potentiated the effect of parathyroid hormone (PTH(1–34)) in a superagonistic manner. EPA or DHA dependent ERK phosphorylation was inhibited by the PTH1R antagonist and by knockdown of PTH1R. Inhibition of PTH1R downstream signaling molecules, protein kinases A (PKA) and C (PKC), reduced EPA and DHA dependent ERK phosphorylation indicating that fatty acids predominantly activate G-protein pathway and not the β-arrestin pathway. Using picosecond time-resolved fluorescence microscopy and a genetically engineered PTH1R sensor (PTH-CC), we detected conformational responses to EPA similar to those caused by PTH(1–34). PTH1R antagonist blocked the EPA induced conformational response of the PTH-CC. Competitive binding studies using fluorescence anisotropy technique showed that EPA and DHA competitively bind to and alter the affinity of PTH1 receptor to PTH(1–34) leading to a superagonistic response. Finally, we showed that EPA stimulates protein kinase B (Akt) phosphorylation in a PTH1R-dependent manner and affects the osteoblast survival pathway, by inhibiting glucocorticoid-induced cell death. Our findings demonstrate for the first time that LCPUFAs, EPA and DHA, can activate PTH1R receptor at nanomolar concentrations and consequently provide a putative molecular mechanism for the action of fatty acids in bone. PMID:23300710

  18. Responses of soil buffering capacity to acid treatment in three typical subtropical forests.

    PubMed

    Jiang, Jun; Wang, Ying-Ping; Yu, Mengxiao; Li, Kun; Shao, Yijing; Yan, Junhua

    2016-09-01

    Elevated anthropogenic acid deposition can significantly affect forest ecosystem functioning by changing soil pH, nutrient balance, and chemical leaching and so on. These effects generally differ among different forests, and the dominant mechanisms for those observed responses often vary, depending on climate, soil conditions and vegetation types. Using soil monoliths (0-40cm) from pine forest (pioneer), coniferous and broadleaved mixed forest (transitional) and broadleaved forest (mature) in southern China, we conducted a leaching experiment with acid treatments at different pH levels (control: pH≈4.5; pH=3.5; pH=2.5). We found that pH3.5 treatment significantly reduced dissolved organic carbon (DOC) concentrations in leachate from the pioneer forest soil. pH2.5 treatment significantly increased concentrations of NO3(-), SO4(2-), Ca(2+), Mg(2+), Al(3+), Fe(3+) and DOC in leachate from the pioneer forest soil, and also concentrations of NO3(-), SO4(2-), Mg(2+), Al(3+), Fe(3+) and DOC in leachate from the transitional forest soil. All acid treatments had no significant effects on concentrations of these chemicals in leachate from the mature forest soil. The responses can be explained by the changes in soil pH, acid neutralizing capacity (ANC) and concentrations of Al and Fe. Our results showed that acid buffering capacity of the pioneer or transitional forest soil was lower than that of the mature forest soil. Therefore preserving mature forests in southern China is important for reducing the adverse impacts of high acid deposition on stream water quality at present and into the future. PMID:27185346

  19. Quantifying bile acid malabsorption helps predict response and tailor sequestrant therapy.

    PubMed

    Orekoya, Oluwafikunayo; McLaughlin, John; Leitao, Eugenia; Johns, Wendy; Lal, Simon; Paine, Peter

    2015-06-01

    Although recognised as a cause of chronic diarrhoea for over forty years, diagnostic tests and treatments for bile acid malabsorption (BAM) remain controversial. Recent National Institute for Health and Care Excellence (NICE) guidelines highlighted the lack of evidence in the field, and called for further research. This retrospective study explores the BAM subtype and severity, the use and response to bile acid sequestrants (BAS) and the prevalence of abnormal colonic histology. 264 selenium-75-labelled homocholic acid conjugated taurine (SeHCAT)-tested patient records were reviewed and the severity and subtype of BAM, presence of colonic histopathology and response to BAS were recorded. 53% of patients tested had BAM, with type-2 BAM in 45% of patients with presumed irritable bowel syndrome. Colonic histological abnormalities were similar overall between patients with (29%) or without (23%) BAM (p = 0.46) and between BAM subtypes, with no significant presence of inflammatory changes. 63% of patients with BAM had a successful BAS response which showed a trend to decreased response with reduced severity. Colestyramine was unsuccessful in 44% (38/87) and 45% of these (17/38) were related to medication intolerance, despite a positive SeHCAT. 47% (7/15) of colestyramine failures had a successful colesevelam response. No patient reported colesevelam intolerance. Quantifying severity of BAM appears to be useful in predicting BAS response. Colesevelam was better tolerated than colestyramine and showed some efficacy in colestyramine failures. Colestyramine failure should not be used to exclude BAM. Colonic histology is of no relevance. PMID:26031975

  20. Acute lung function responses to ambient acid aerosol exposures in children

    SciTech Connect

    Raizenne, M.E.; Burnett, R.T.; Stern, B.; Franklin, C.A.; Spengler, J.D.

    1989-02-01

    We examined the relationship between lung function changes and ambient acid aerosol episodes in children attending a residential summer camp. Young females (112) performed daily spirometry, and 96 were assessed on one occasion for airway hyperresponsiveness using a methacholine bronchoprovocation test. Air quality measurements were performed on site and four distinct acid aerosol episodes were observed during the 41-day study. The maximum values observed during the 41-day study were: O/sub 3/ at 143 ppb; H/sub 2/SO/sub 4/ at 47.7 micrograms/m/sup 3/; and (H+) at 550 nmole/m/sup 3/. Maximum decrements of 3.5 and 7% for FEV1 and PEF, respectively, were observed to be associated with the air pollution episodes. There was some evidence of a differential lung function response to the episodes where children with a positive response to a methacholine challenge had larger decrements compared to their nonresponsive counterparts.

  1. Biomolecular Interactions and Biological Responses of Emerging Two-Dimensional Materials and Aromatic Amino Acid Complexes.

    PubMed

    Mallineni, Sai Sunil Kumar; Shannahan, Jonathan; Raghavendra, Achyut J; Rao, Apparao M; Brown, Jared M; Podila, Ramakrishna

    2016-07-01

    The present work experimentally investigates the interaction of aromatic amino acids viz., tyrosine, tryptophan, and phenylalnine with novel two-dimensional (2D) materials including graphene, graphene oxide (GO), and boron nitride (BN). Photoluminescence, micro-Raman spectroscopy, and cyclic voltammetry were employed to investigate the nature of interactions and possible charge transfer between 2D materials and amino acids. Graphene and GO were found to interact strongly with aromatic amino acids through π-π stacking, charge transfer, and H-bonding. Particularly, it was observed that both physi and chemisorption are prominent in the interactions of GO/graphene with phenylalanine and tryptophan while tyrosine exhibited strong chemisorption on graphene and GO. In contrast, BN exhibited little or no interactions, which could be attributed to localized π-electron clouds around N atoms in BN lattice. Lastly, the adsorption of amino acids on 2D materials was observed to considerably change their biological response in terms of reactive oxygen species generation. More importantly, these changes in the biological response followed the same trends observed in the physi and chemisorption measurements. PMID:27281436

  2. Highly Lewis Acidic Arylboronate Esters Capable of Colorimetric Turn-On Response.

    PubMed

    Oehlke, Alexander; Auer, Alexander A; Schreiter, Katja; Friebe, Nadine; Spange, Stefan

    2015-12-01

    A series of boronate-π-acceptor compounds containing different types of π bridges (1,4-phenylen or thien-2,5-diyl or furan-2,5-diyl) that link the switchable boronate ester group with the efficient TCF acceptor group (TCF=2-dicyanomethylen-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran) has been synthesized. A TCF chromophore of this type undergoes transition to a donor-π-acceptor compound upon coordination of Lewis bases at the Lewis acidic boron center, which is accompanied by an enhanced intramolecular charge-transfer interaction. The Lewis acid character has been investigated by spectroscopic measurements (UV/Vis, NMR spectroscopies) as well as DFT and ab initio-based calculations. It is shown that the TCF acceptor group and thiophene or furan π-bridges directly bound to the boron atom cooperatively increase the Lewis acidity. UV/Vis titration experiments confirm fluoride binding constants in the range of up to 10(8)  M(-1) in CH2 Cl2 . In addition to the strong boron fluoride binding motif, Lewis interactions also occur with weaker Lewis bases, such as pyridine or aliphatic alcohols. The unique combination of chromophoric and Lewis acidic properties is responsible for the intense colorimetric turn-on response detectable after complex formation. PMID:26489784

  3. Transcriptome analysis of Rhizopus oryzae in response to xylose during fumaric acid production.

    PubMed

    Xu, Qing; Liu, Ying; Li, Shuang; Jiang, Ling; Huang, He; Wen, Jianping

    2016-08-01

    Xylose is one of the most abundant lignocellulosic components, but it cannot be used by R. oryzae for fumaric acid production. Here, we applied high-throughput RNA sequencing to generate two transcriptional maps of R. oryzae following fermentation in glucose or xylose. The differential expression analysis showed that, genes involved in amino acid metabolism, fatty acid metabolism, and gluconeogenesis, were up-regulated in response to xylose. Moreover, we discovered the potential presence of oxidative stress in R. oryzae during xylose fermentation. To adapt to this unfavorable condition, R. oryzae displayed reduced growth and induce of a number of antioxidant enzymes, including genes involved in glutathione, trehalose synthesis, and the proteasomal pathway. These responses might divert the flow of carbon required for the accumulation of fumaric acid. Furthermore, using high-throughput RNA sequencing, we identified a large number of novel transcripts and a substantial number of genes that underwent alternative splicing. Our analysis provides remarkable insight into the mechanisms underlying xylose fermentation by R. oryzae. These results may reveal potential target genes or strategies to improve xylose fermentation. PMID:27170374

  4. Altered growth response to exogenous auxin and gibberellic acid by gravistimulation in pulvini of Avena sativa

    NASA Technical Reports Server (NTRS)

    Brock, T. G.; Kaufman, P. B.

    1988-01-01

    Pulvini of excised segments from oats (Avena sativa L. cv Victory) were treated unilaterally with indoleacetic acid (IAA) or gibberellic acid (GA3) with or without gravistimulation to assess the effect of gravistimulation on hormone action. Optimum pulvinus elongation growth (millimeters) and segment curvature (degrees) over 24 hours were produced by 100 micromolar IAA in vertical segments. The curvature response to IAA at levels greater than 100 micromolar, applied to the lower sides of gravistimulated (90 degrees) pulvini, was significantly less than the response to identical levels in vertical segments. Furthermore, the bending response of pulvini to 100 micromolar IAA did not vary significantly over a range of presentation angles between 0 and 90 degrees. In contrast, the response to IAA at levels less than 10 micromolar, with gravistimulation, was approximately the sum of the responses to gravistimulation alone and to IAA without gravistimulation. This was observed over a range of presentation angles. Also, GA3 (0.3-30 micromolar) applied to the lower sides of horizontal segments significantly enhanced pulvinus growth and segment curvature, although exogenous GA3 over a range of concentrations had no effect on pulvinus elongation growth or segment curvature in vertical segments. The response to GA3 (10 micromolar) plus IAA (1.0 or 100 micromolar) was additive for either vertical or horizontal segments. These results indicate that gravistimulation produces changes in pulvinus responsiveness to both IAA and GA3 and that the changes are unique for each growth regulator. It is suggested that the changes in responsiveness may result from processes at the cellular level other than changes in hormonal sensitivity.

  5. The acid adaptive tolerance response in Campylobacter jejuni induces a global response, as suggested by proteomics and microarrays

    PubMed Central

    Varsaki, Athanasia; Murphy, Caroline; Barczynska, Alicja; Jordan, Kieran; Carroll, Cyril

    2015-01-01

    Campylobacter jejuni CI 120 is a natural isolate obtained during poultry processing and has the ability to induce an acid tolerance response (ATR) to acid + aerobic conditions in early stationary phase. Other strains tested they did not induce an ATR or they induced it in exponential phase. Campylobacter spp. do not contain the genes that encode the global stationary phase stress response mechanism. Therefore, the aim of this study was to identify genes that are involved in the C. jejuni CI 120 early stationary phase ATR, as it seems to be expressing a novel mechanism of stress tolerance. Two-dimensional gel electrophoresis was used to examine the expression profile of cytosolic proteins during the C. jejuni CI 120 adaptation to acid + aerobic stress and microarrays to determine the genes that participate in the ATR. The results indicate induction of a global response that activated a number of stress responses, including several genes encoding surface components and genes involved with iron uptake. The findings of this study provide new insights into stress tolerance of C. jejuni, contribute to a better knowledge of the physiology of this bacterium and highlight the diversity among different strains. PMID:26221965

  6. Regulating inflammation using acid-responsive electrospun fibrous scaffolds for skin scarless healing.

    PubMed

    Yuan, Ziming; Zhao, Jingwen; Chen, Yigang; Yang, Zhili; Cui, Wenguo; Zheng, Qi

    2014-01-01

    Skin injury in adult mammals brings about a series of events and inflammation in the wounded area is initiated first and provides lots of inflammatory factors, which is critical for the final scar formation. While the postinjured skin of fetus and nude mice heals scarlessly owing to the absence of inflammation or immunodeficient, we designed a feasible acid-responsive ibuprofen-loaded poly(L-lactide) (PLLA) fibrous scaffolds via doping sodium bicarbonate to prevent excessive inflammation and achieve scarless healing finally. The morphological results of in vivo experiments revealed that animals treated with acid-responsive ibuprofen-loaded PLLA fibrous scaffolds exhibited alleviative inflammation, accelerated healing process, and regulated collagen deposition via interference in the collagen distribution, the α-smooth muscle actin (α-SMA), and the basic fibroblast growth factor (bFGF) expression. The lower ratios of collagen I/collagen III and TGF-β1/TGF-β3 and higher ratio of matrix metalloproteinase-1 (MMP-1)/tissue inhibitor of metalloproteinase-1 (TIMP-1) in acid-responsive ibuprofen-loaded PLLA fibrous scaffolds group were confirmed by real-time qPCR as well. These results suggest that inhibiting the excessive inflammation will result in regular collagen distribution and appropriate ratio between the factors, which promote or suppress the scar formation, then decrease the scar area, and finally achieve the scarless healing. PMID:24795507

  7. Regulating Inflammation Using Acid-Responsive Electrospun Fibrous Scaffolds for Skin Scarless Healing

    PubMed Central

    Yuan, Ziming; Zhao, Jingwen; Chen, Yigang; Yang, Zhili; Zheng, Qi

    2014-01-01

    Skin injury in adult mammals brings about a series of events and inflammation in the wounded area is initiated first and provides lots of inflammatory factors, which is critical for the final scar formation. While the postinjured skin of fetus and nude mice heals scarlessly owing to the absence of inflammation or immunodeficient, we designed a feasible acid-responsive ibuprofen-loaded poly(L-lactide) (PLLA) fibrous scaffolds via doping sodium bicarbonate to prevent excessive inflammation and achieve scarless healing finally. The morphological results of in vivo experiments revealed that animals treated with acid-responsive ibuprofen-loaded PLLA fibrous scaffolds exhibited alleviative inflammation, accelerated healing process, and regulated collagen deposition via interference in the collagen distribution, the α-smooth muscle actin (α-SMA), and the basic fibroblast growth factor (bFGF) expression. The lower ratios of collagen I/collagen III and TGF-β1/TGF-β3 and higher ratio of matrix metalloproteinase-1 (MMP-1)/tissue inhibitor of metalloproteinase-1 (TIMP-1) in acid-responsive ibuprofen-loaded PLLA fibrous scaffolds group were confirmed by real-time qPCR as well. These results suggest that inhibiting the excessive inflammation will result in regular collagen distribution and appropriate ratio between the factors, which promote or suppress the scar formation, then decrease the scar area, and finally achieve the scarless healing. PMID:24795507

  8. Acid-Responsive Therapeutic Polymer for Prolonging Nanoparticle Circulation Lifetime and Destroying Drug-Resistant Tumors.

    PubMed

    Piao, Ji-Gang; Gao, Feng; Yang, Lihua

    2016-01-13

    How to destroy drug-resistant tumor cells remains an ongoing challenge for cancer treatment. We herein report on a therapeutic nanoparticle, aHLP-PDA, which has an acid-activated hemolytic polymer (aHLP) grafted onto photothermal polydopamine (PDA) nanosphere via boronate ester bond, in efforts to ablate drug-resistant tumors. Upon exposure to oxidative stress and/or near-infrared laser irradiation, aHLP-PDA nanoparticle responsively releases aHLP, likely via responsive cleavage of boronate ester bond, and thus responsively exhibits acid-facilitated mammalian-membrane-disruptive activity. In vitro cell studies with drug-resistant and/or thermo-tolerant cancer cells show that the aHLP-PDA nanoparticle demonstrates preferential cytotoxicity at acidic pH over physiological pH. When administered intravenously, the aHLP-PDA nanoparticle exhibits significantly prolonged blood circulation lifetime and enhanced tumor uptake compared to bare PDA nanosphere, likely owing to aHLP's stealth effects conferred by its zwitterionic nature at blood pH. As a result, the aHLP-PDA nanoparticle effectively ablates drug-resistant tumors, leading to 100% mouse survival even on the 32nd day after suspension of photothermal treatment, as demonstrated with the mouse model. This work suggests that a combination of nanotechnology with lessons learned in bacterial antibiotic resistance may offer a feasible and effective strategy for treating drug-resistant cancers often found in relapsing patients. PMID:26654626

  9. Projection of response of trees and forests to acidic deposition and associated pollutants

    SciTech Connect

    Kiester, A.R.; Ford, E.D.; Avery, A.; Gay, C.; Droessler, T.

    1990-09-01

    In 1986 the National Acid Precipitation Assessment Program (NAPAP) established the Forest Response Program (FRP) to assess the effects of acidic deposition and associated pollutants on forests. Modeling studies were developed in parallel with both field studies on the pattern and trends of forest condition and physiological studies of seedlings, saplings, and branches of mature trees. The goals of the modeling effort were to simulate the dynamics of the processes by which acidic deposition and ozone affect tree physiological processes and therefore lead to changes in growth. Results from models of the physiological function of leaves, branches, roots, xylem, and canopies are presented here. These models illustrate three aspects of the dynamics of these processes. First, growth and the effects of pollutants are stochastic processes; that is, they vary randomly over time. The models help to account for the large amount of variability seen in normal field conditions. Second, some physiological processes can compensate for the effects of acidic deposition or ozone. Third, pollutants may have more than one effect on tree growth, and these effects may be synergistic. The potential nonlinearities and the variabilities demonstrated by these models lead to the conclusions that forest health effects may be developing that are not yet apparent; and for regulation of acidic deposition and associated pollutants to have a detectable effect, regulatory changes will probably have to be of substantial magnitude.

  10. C. butyricum lipoteichoic acid inhibits the inflammatory response and apoptosis in HT-29 cells induced by S. aureus lipoteichoic acid.

    PubMed

    Wang, Jinbo; Qi, Lili; Mei, Lehe; Wu, Zhige; Wang, Hengzheng

    2016-07-01

    Lipoteichoic acid (LTA) is one of microbe-associated molecular pattern (MAMP) molecules of gram-positive bacteria. In this study, we demonstrated that Clostridium butyricum LTA (bLTA) significantly inhibited the inflammatory response and apoptosis induced by Staphylococcus aureus LTA (aLTA) in HT-29 cells. aLTA stimulated the inflammatory responses by activating a strong signal transduction cascade through NF-κB and ERK, but bLTA did not activate the signaling pathway. bLTA pretreatment inhibited the activation of the NF-κB and ERK signaling pathway induced by aLTA. The expression and release of cytokines such as IL-8 and TNF-α were also suppressed by bLTA pretreatment. aLTA treatment induced apoptosis in HT-29 cells, but bLTA did not affect the viability of the cells. Further study indicated that bLTA inhibited apoptosis in HT-29 cells induced by aLTA. These results suggest that bLTA may act as an aLTA antagonist and that an antagonistic bLTA may be a useful agent for suppressing the pro-inflammatory activities of gram-positive pathogenic bacteria. PMID:27020942

  11. Arctigenic acid, the key substance responsible for the hypoglycemic activity of Fructus Arctii.

    PubMed

    Xu, Zhaohui; Gu, Chenchen; Wang, Kai; Ju, Jiaxing; Wang, Haiying; Ruan, Kefeng; Feng, Yi

    2015-01-15

    We have reported the antidiabetic activity of the total lignans from Fructus arctii (TLFA) against alloxan-induced diabetes in mice and rats. In this study, arctigenic acid was found to be the main metabolite in rat plasma detected by UPLC/MS and HPLC/MS/MS after oral administration of TLFA. For the first time, its hypoglycemic activity and acute oral toxicity were evaluated in Goto-Kakizaki (GK) rats, a spontaneous type 2 diabetic animal model, and ICR mice respectively. GK rats were orally given arctigenic acid (50 mg/kg) twice daily before each meal for 12 weeks. The treatment reduced the elevated plasma glucose, glycosylated hemoglobin and showed significant improvement in glucose tolerance in glucose fed hyperglycemic GK rats. We found that the hypoglycemic effect of arctigenic acid was partly due to the stimulation on insulin secretion, whereas the body weight was not affected by arctigenic acid administration in GK rats. Meanwhile, there was no observable acute toxicity of arctigenic acid treatment at the dosage of 280 mg/kg body weight daily in the acute 14-day toxicity study in mice. This study demonstrates that arctigenic acid may be the main metabolite in the rat serum after oral administration of TLFA, which showed significant hypoglycemic effect in GK rats, and low acute toxicity in ICR mice. The result prompts us that arctigenic acid is the key substance responsible for Fructus Arctii antidiabetic activity and it has a great potential to be further developed as a novel therapeutic agent for diabetes in humans. PMID:25636881

  12. Epoxyeicosatrienoic acids protect cardiac cells during starvation by modulating an autophagic response

    PubMed Central

    Samokhvalov, V; Alsaleh, N; El-Sikhry, H E; Jamieson, K L; Chen, C B; Lopaschuk, D G; Carter, C; Light, P E; Manne, R; Falck, J R; Seubert, J M

    2013-01-01

    Epoxyeicosatrienoic acids (EETs) are cytochrome P450 epoxygenase metabolites of arachidonic acid involved in regulating pathways promoting cellular protection. We have previously shown that EETs trigger a protective response limiting mitochondrial dysfunction and reducing cellular death. Considering it is unknown how EETs regulate cell death processes, the major focus of the current study was to investigate their role in the autophagic response of HL-1 cells and neonatal cardiomyocytes (NCMs) during starvation. We employed a dual-acting synthetic analog UA-8 (13-(3-propylureido)tridec-8-enoic acid), possessing both EET-mimetic and soluble epoxide hydrolase (sEH) inhibitory properties, or 14,15-EET as model EET molecules. We demonstrated that EETs significantly improved viability and recovery of starved cardiac cells, whereas they lowered cellular stress responses such as caspase-3 and proteasome activities. Furthermore, treatment with EETs resulted in preservation of mitochondrial functional activity in starved cells. The protective effects of EETs were abolished by autophagy-related gene 7 (Atg7) short hairpin RNA (shRNA) or pharmacological inhibition of autophagy. Mechanistic evidence demonstrated that sarcolemmal ATP-sensitive potassium channels (pmKATP) and enhanced activation of AMP-activated protein kinase (AMPK) played a crucial role in the EET-mediated effect. Our data suggest that the protective effects of EETs involve regulating the autophagic response, which results in a healthier pool of mitochondria in the starved cardiac cells, thereby representing a novel mechanism of promoting survival of cardiac cells. Thus, we provide new evidence highlighting a central role of the autophagic response in linking EETs with promoting cell survival during deep metabolic stress such as starvation. PMID:24157879

  13. Bacillus cereus cell response upon exposure to acid environment: toward the identification of potential biomarkers

    PubMed Central

    Desriac, Noémie; Broussolle, Véronique; Postollec, Florence; Mathot, Anne-Gabrielle; Sohier, Danièle; Coroller, Louis; Leguerinel, Ivan

    2013-01-01

    Microorganisms are able to adapt to different environments and evolve rapidly, allowing them to cope with their new environments. Such adaptive response and associated protections toward other lethal stresses, is a crucial survival strategy for a wide spectrum of microorganisms, including food spoilage bacteria, pathogens, and organisms used in functional food applications. The growing demand for minimal processed food yields to an increasing use of combination of hurdles or mild preservation factors in the food industry. A commonly used hurdle is low pH which allows the decrease in bacterial growth rate but also the inactivation of pathogens or spoilage microorganisms. Bacillus cereus is a well-known food-borne pathogen leading to economical and safety issues in food industry. Because survival mechanisms implemented will allow bacteria to cope with environmental changes, it is important to provide understanding of B. cereus stress response. Thus this review deals with the adaptive traits of B. cereus cells facing to acid stress conditions. The acid stress response of B. cereus could be divided into four groups (i) general stress response (ii) pH homeostasis, (iii) metabolic modifications and alkali production and (iv) secondary oxidative stress response. This current knowledge may be useful to understand how B. cereus cells may cope to acid environment such as encountered in food products and thus to find some molecular biomarkers of the bacterial behavior. These biomarkers could be furthermore used to develop new microbial behavior prediction tools which can provide insights into underlying molecular physiological states which govern the behavior of microorganisms and thus opening the avenue toward the detection of stress adaptive behavior at an early stage and the control of stress-induced resistance throughout the food chain. PMID:24106490

  14. Bacillus cereus cell response upon exposure to acid environment: toward the identification of potential biomarkers.

    PubMed

    Desriac, Noémie; Broussolle, Véronique; Postollec, Florence; Mathot, Anne-Gabrielle; Sohier, Danièle; Coroller, Louis; Leguerinel, Ivan

    2013-01-01

    Microorganisms are able to adapt to different environments and evolve rapidly, allowing them to cope with their new environments. Such adaptive response and associated protections toward other lethal stresses, is a crucial survival strategy for a wide spectrum of microorganisms, including food spoilage bacteria, pathogens, and organisms used in functional food applications. The growing demand for minimal processed food yields to an increasing use of combination of hurdles or mild preservation factors in the food industry. A commonly used hurdle is low pH which allows the decrease in bacterial growth rate but also the inactivation of pathogens or spoilage microorganisms. Bacillus cereus is a well-known food-borne pathogen leading to economical and safety issues in food industry. Because survival mechanisms implemented will allow bacteria to cope with environmental changes, it is important to provide understanding of B. cereus stress response. Thus this review deals with the adaptive traits of B. cereus cells facing to acid stress conditions. The acid stress response of B. cereus could be divided into four groups (i) general stress response (ii) pH homeostasis, (iii) metabolic modifications and alkali production and (iv) secondary oxidative stress response. This current knowledge may be useful to understand how B. cereus cells may cope to acid environment such as encountered in food products and thus to find some molecular biomarkers of the bacterial behavior. These biomarkers could be furthermore used to develop new microbial behavior prediction tools which can provide insights into underlying molecular physiological states which govern the behavior of microorganisms and thus opening the avenue toward the detection of stress adaptive behavior at an early stage and the control of stress-induced resistance throughout the food chain. PMID:24106490

  15. Quantitative Proteomic Profiling of Early and Late Responses to Salicylic Acid in Cucumber Leaves

    PubMed Central

    Li, Liang; Shang, Qing-Mao

    2016-01-01

    Salicylic acid (SA) is an important phytohormone that plays vital regulatory roles in plant growth, development, and stress responses. However, studies on the molecular mechanism of SA, especially during the early SA responses, are lagging behind. In this study, we initiated a comprehensive isobaric tag for relative and absolute quantitation (iTRAQ)-based proteomic analysis to explore the early and late SA-responsive proteins in leaves of cucumber (Cucumis sativus L.) seedlings. Upon SA application through the roots, endogenous SA accumulated in cucumber leaves. By assaying the changes in marker gene expression and photosynthetic rate, we collected samples at 12 h and 72 h post treatment (hpt) to profile the early and late SA responsiveness, respectively. The iTRAQ assay followed by tandem mass spectrometry revealed 135 differentially expressed proteins (DEPs) at 12 hpt and 301 DEPs at 72 hpt. The functional categories for these SA-responsive proteins included in a variety of biochemical processes, including photosynthesis, redox homeostasis, carbohydrate and energy metabolism, lipid metabolism, transport, protein folding and modification, proteolysis, cell wall organization, and the secondary phenylpropanoid pathway. Conclusively, based on the abundant changes of these DEPs, together with their putative functions, we proposed a possible SA-responsive protein network. It appears that SA could elicit reactive oxygen species (ROS) production via enhancing the photosynthetic electron transferring, and then confer some growth-promoting and stress-priming effects on cells during the late phase, including enhanced photosynthesis and ROS scavenging, altered carbon metabolic flux for the biosynthesis of amino acids and nucleotides, and cell wall reorganization. Overall, the present iTRAQ assay provides higher proteome coverage and deepened our understanding of the molecular basis of SA-responses. PMID:27551830

  16. Quantitative Proteomic Profiling of Early and Late Responses to Salicylic Acid in Cucumber Leaves.

    PubMed

    Dong, Chun-Juan; Cao, Ning; Li, Liang; Shang, Qing-Mao

    2016-01-01

    Salicylic acid (SA) is an important phytohormone that plays vital regulatory roles in plant growth, development, and stress responses. However, studies on the molecular mechanism of SA, especially during the early SA responses, are lagging behind. In this study, we initiated a comprehensive isobaric tag for relative and absolute quantitation (iTRAQ)-based proteomic analysis to explore the early and late SA-responsive proteins in leaves of cucumber (Cucumis sativus L.) seedlings. Upon SA application through the roots, endogenous SA accumulated in cucumber leaves. By assaying the changes in marker gene expression and photosynthetic rate, we collected samples at 12 h and 72 h post treatment (hpt) to profile the early and late SA responsiveness, respectively. The iTRAQ assay followed by tandem mass spectrometry revealed 135 differentially expressed proteins (DEPs) at 12 hpt and 301 DEPs at 72 hpt. The functional categories for these SA-responsive proteins included in a variety of biochemical processes, including photosynthesis, redox homeostasis, carbohydrate and energy metabolism, lipid metabolism, transport, protein folding and modification, proteolysis, cell wall organization, and the secondary phenylpropanoid pathway. Conclusively, based on the abundant changes of these DEPs, together with their putative functions, we proposed a possible SA-responsive protein network. It appears that SA could elicit reactive oxygen species (ROS) production via enhancing the photosynthetic electron transferring, and then confer some growth-promoting and stress-priming effects on cells during the late phase, including enhanced photosynthesis and ROS scavenging, altered carbon metabolic flux for the biosynthesis of amino acids and nucleotides, and cell wall reorganization. Overall, the present iTRAQ assay provides higher proteome coverage and deepened our understanding of the molecular basis of SA-responses. PMID:27551830

  17. Behavioral and electrophysiological responses of Culex quinquefasciatus to certain fatty acid esters.

    PubMed

    Seenivasagan, Thangaraj; Guha, Lopamudra; Iqbal, S Thanvir

    2013-12-01

    Oviposition response of gravid Culex quinquefasciatus females to a series of synthetic fatty acid esters was evaluated at 10ppm under laboratory conditions. Octyl tridecanoate and propyl octadecanoate elicited 85% and 73% increased ovipositional responses respectively, compared to control, among the 16 esters tested. Other 14 esters showed highly significant repellency (67-96%) to gravid females. Standard 3-methyl indole received 69% increased egg deposition compared to control. In the Y-tube olfactometer, gravid C. quinquefasciatus females exhibited 78, 64% and 58% orientation respectively to octyl tridecanoate, propyl octadecanoate and 3-methyl indole. Gravid females exhibited 19-41% reduced orientation toward treatment odors of other esters significantly different from respective control. Electroantennogram studies revealed 4-18-fold increased antennal response, in which 3-methyl indole, octyl tridecanoate and propyl octadecanoate elicited 8-, 18- and 15-fold EAG response respectively, compared to control. Relative EAG response of octyl tridecanoate compared to standard 3-methyl indole was significantly different. Reduced EAG responses were elicited by FAE-06, -08, -13, -14 and -15, while the relative EAG responses of other esters were at par with the standard stimulus. These, esters could be utilized potentially as oviposition attractants and repellents against C. quinquefasciatus females to reduce the breeding in polluted water along with existing integrated vector control methods. PMID:24055543

  18. The NASA Dryden AAR Project: A Flight Test Approach to an Aerial Refueling System

    NASA Technical Reports Server (NTRS)

    Hansen, Jennifer L.; Murray, James E.; Campos, Norma V.

    2004-01-01

    The integration of uninhabited aerial vehicles (UAVs) into controlled airspace has generated a new era of autonomous technologies and challenges. Autonomous aerial refueling would enable UAVs to travel further distances and loiter for extended periods over time-critical targets. The NASA Dryden Flight Research Center recently has completed a flight research project directed at developing a dynamic hose and drogue system model to support the development of an automated aerial refueling system. A systematic dynamic model of the hose and drogue system would include the effects of various influences on the system, such as flight condition, hose and drogue type, tanker type and weight, receiver type, and tanker and receiver maneuvering. Using two NASA F/A-18 aircraft and a conventional hose and drogue aerial refueling store from the Navy, NASA has obtained flight research data that document the response of the hose and drogue system to these effects. Preliminary results, salient trends, and important lessons are presented.

  19. The response of amino acid cycling to global change across multiple biomes: Feedbacks on soil nitrogen availability

    NASA Astrophysics Data System (ADS)

    Brzostek, E. R.; Finzi, A. C.

    2010-12-01

    The cycling of organic nitrogen (N) in soil links soil organic matter decomposition to ecosystem productivity. Amino acids are a key pool of organic N in the soil, whose cycling is sensitive to alterations in microbial demand for carbon and N. Further, the amino acids released from the breakdown of protein by proteolytic enzymes are an important source of N that supports terrestrial productivity. The objective of this study was to measure changes in amino acid cycling in response to experimental alterations of precipitation and temperature in twelve global change experiments during the 2009 growing season. The study sites ranged from arctic tundra to xeric grasslands. The treatments experimentally increased temperature, increased or decreased precipitation, or some combination of both factors. The response of amino acid cycling to temperature and precipitation manipulations tended to be site specific, but the responses could be placed into a common framework. Changes in soil moisture drove a large response in amino acid cycling. Precipitation augmentation in xeric and mesic sites increased both amino acid pool sizes and production. However, treatments that decreased precipitation drove decreases in amino acid cycling in xeric sites, but led to increases in amino acid cycling in more mesic sites. Across sites, the response to soil warming was horizon specific. Amino acid cycling in organic rich horizons responded positively to warming, while negative responses were exhibited in lower mineral soil horizons. The variable response likely reflects a higher availability of protein substrate to sustain high rates of proteolytic enzyme activity in organic rich horizons. Overall, these results suggest that soil moisture and the availability of protein substrate may be important factors that mediate the response of amino acid cycling to predicted increases in soil temperatures.

  20. Growth responses of 53 open-pollinated loblolly pine families to ozone and acid rain

    SciTech Connect

    McLaughlin, S.B.; Edwards, N.T.; Hanson, P.J.

    1994-03-01

    Field exposures of 9950 containerized 12-wk-old loblolly pine (Pinustaeda L.) seedlings representing 53 commercially important, open-pollinated families were conducted to evaluate individual and interactive effects of acid rain and O{sub 3} on growth response. A 36-plot field research facility comprised of 33 open-top chambers and three open plots was used to test effects of five O{sub 3} levels that included ambient (A) and seasonally integrated levels that were 0.53, 1.10, 1.58, or 2.15 times ambient. Individual effects of three levels of simulated acid rain (pH 3.3, 4.5, and 5.2) as well as their interaction with O{sub 3} at 0.53A, 1.58A, and 2.15A levels were also included. Exposure to ambient air reduced average growth in height (26%), diameter (5%), and volume (14%) compared with growth of seedlings exposed to a 47% lower dose in charcoal filtered (CF) air. Responses to increasing O{sub 3} above ambient levels varied widely between families, became increasingly inhibitory at the highest O{sub 3} levels, but did not significantly exceed growth reductions found in ambient air. Diameter growth was reduced in most families by all levels of O{sub 3} addition. Acid rain caused a general stimulation of height growth at ambient levels (pH 4.5), while both height and diameter growth were reduced at a mean pH of 3.3. Significant antagonism between rainfall acidity and O{sub 3} effects on height and biomass increment was detected with increasing pollutant concentrations. Ozone reduced root/shoot biomass in most families, while acid rain did not. 51 refs., 6 figs., 6 tabs.

  1. Functional annotation of the transcriptome of Sorghum bicolor in response to osmotic stress and abscisic acid

    PubMed Central

    2011-01-01

    Background Higher plants exhibit remarkable phenotypic plasticity allowing them to adapt to an extensive range of environmental conditions. Sorghum is a cereal crop that exhibits exceptional tolerance to adverse conditions, in particular, water-limiting environments. This study utilized next generation sequencing (NGS) technology to examine the transcriptome of sorghum plants challenged with osmotic stress and exogenous abscisic acid (ABA) in order to elucidate genes and gene networks that contribute to sorghum's tolerance to water-limiting environments with a long-term aim of developing strategies to improve plant productivity under drought. Results RNA-Seq results revealed transcriptional activity of 28,335 unique genes from sorghum root and shoot tissues subjected to polyethylene glycol (PEG)-induced osmotic stress or exogenous ABA. Differential gene expression analyses in response to osmotic stress and ABA revealed a strong interplay among various metabolic pathways including abscisic acid and 13-lipoxygenase, salicylic acid, jasmonic acid, and plant defense pathways. Transcription factor analysis indicated that groups of genes may be co-regulated by similar regulatory sequences to which the expressed transcription factors bind. We successfully exploited the data presented here in conjunction with published transcriptome analyses for rice, maize, and Arabidopsis to discover more than 50 differentially expressed, drought-responsive gene orthologs for which no function had been previously ascribed. Conclusions The present study provides an initial assemblage of sorghum genes and gene networks regulated by osmotic stress and hormonal treatment. We are providing an RNA-Seq data set and an initial collection of transcription factors, which offer a preliminary look into the cascade of global gene expression patterns that arise in a drought tolerant crop subjected to abiotic stress. These resources will allow scientists to query gene expression and functional

  2. Role of cholecystokinin in pancreatic exocrine response to intraluminal amino acids and fat.

    PubMed

    Stubbs, R S; Stabile, B E

    1985-03-01

    Controversy continues over the relative contributions made by hormonal and neural mechanisms in the exocrine pancreatic response to ingested food. The recent description of the drug proglumide as a specific, competitive cholecystokinin (CCK)/gastrin receptor antagonist has permitted reevaluation of the role of CCK in this process. In chronic pancreatic fistula dogs, dose-response studies were performed to determine the effect of proglumide on the pancreatic responses to octapeptide of CCK (CCK-OP), intravenous bethanechol, intraduodenal amino acids, and intraduodenal fat. Pancreatic volume, protein, and bicarbonate outputs to all doses of CCK-OP were inhibited significantly (P less than 0.05) in a competitive manner, consistent with the proposed mode of action of proglumide. In contrast, proglumide caused only minor and insignificant inhibition of the output responses to intravenous bethanechol. Virtually complete inhibition to all doses of intraduodenal amino acids and fat was observed with proglumide administration. If indeed proglumide is a specific CCK receptor antagonist, these results support the hypothesis that CCK is the major mediator of the intestinal phase of exocrine pancreatic secretion. PMID:2858160

  3. The Small Ethylene Response Factor ERF96 is Involved in the Regulation of the Abscisic Acid Response in Arabidopsis

    DOE PAGESBeta

    Wang, Xiaoping; Liu, Shanda; Tian, Hainan; Wang, Shucai; Chen, Jin-Gui

    2015-11-26

    We report that ethylene regulates many aspects of plant growth and development including seed germination, leaf senescence, and fruit ripening, and of plant responses to environmental stimuli including both biotic and abiotic stresses. Ethylene response factors (ERFs) are plant-specific transcription factors and are a subfamily of the AP2 (APETALA2)/ERF transcription factor family. The function of many members in this large gene family remains largely unknown. ERF96, a member of the Group IX ERF family transcription factors, has recently been shown to be a transcriptional activator that is involved in plant defense response in Arabidopsis. Here we provide evidence that ERF96more » is a positive regulator of abscisic acid (ABA) responses. Bioinformatics analysis indicated that there are a total four small ERFs in Arabidopsis including ERF95, ERF96, ERF97, and ERF98, and that ERF96 forms a cluster with ERF95 and ERF97. By using quantitative RT-PCR, we found that ERF96 is expressed in all tissues and organs examined except roots, with relatively high expression in flowers and seeds. Results from the protoplast transfection assay indicated that the EDLL motif-containing C-terminal domain is responsible for ERF96’s transcriptional activity. Although loss-of-function mutant of ERF96 was morphologically similar to wild type plants, transgenic plants overexpressing ERF96 had smaller rosette size and were delayed in flowering time. In ABA sensitivity assays, we found that ERF96 overexpression plants were hypersensitive to ABA in terms of ABA inhibition of seed germination, early seedling development and root elongation. Consistent with these observations, elevated transcript levels of some ABA-responsive genes including RD29A, ABI5, ABF3, ABF4, P5CS, and COR15A were observed in the transgenic plants in the presence of ABA. However, in the absence of ABA treatment, the transcript levels of these ABA-responsive genes remained largely unchanged. Our experiments also showed

  4. The Small Ethylene Response Factor ERF96 is Involved in the Regulation of the Abscisic Acid Response in Arabidopsis

    PubMed Central

    Wang, Xiaoping; Liu, Shanda; Tian, Hainan; Wang, Shucai; Chen, Jin-Gui

    2015-01-01

    Ethylene regulates many aspects of plant growth and development including seed germination, leaf senescence, and fruit ripening, and of plant responses to environmental stimuli including both biotic and abiotic stresses. Ethylene response factors (ERFs) are plant-specific transcription factors and are a subfamily of the AP2 (APETALA2)/ERF transcription factor family. The function of many members in this large gene family remains largely unknown. ERF96, a member of the Group IX ERF family transcription factors, has recently been shown to be a transcriptional activator that is involved in plant defense response in Arabidopsis. Here we provide evidence that ERF96 is a positive regulator of abscisic acid (ABA) responses. Bioinformatics analysis indicated that there are a total four small ERFs in Arabidopsis including ERF95, ERF96, ERF97, and ERF98, and that ERF96 forms a cluster with ERF95 and ERF97. By using quantitative RT-PCR, we found that ERF96 is expressed in all tissues and organs examined except roots, with relatively high expression in flowers and seeds. Results from the protoplast transfection assay indicated that the EDLL motif-containing C-terminal domain is responsible for ERF96’s transcriptional activity. Although loss-of-function mutant of ERF96 was morphologically similar to wild type plants, transgenic plants overexpressing ERF96 had smaller rosette size and were delayed in flowering time. In ABA sensitivity assays, we found that ERF96 overexpression plants were hypersensitive to ABA in terms of ABA inhibition of seed germination, early seedling development and root elongation. Consistent with these observations, elevated transcript levels of some ABA-responsive genes including RD29A, ABI5, ABF3, ABF4, P5CS, and COR15A were observed in the transgenic plants in the presence of ABA. However, in the absence of ABA treatment, the transcript levels of these ABA-responsive genes remained largely unchanged. Our experiments also showed that water loss in ERF

  5. The Small Ethylene Response Factor ERF96 is Involved in the Regulation of the Abscisic Acid Response in Arabidopsis

    DOE PAGESBeta

    Wang, Xiaoping; Liu, Shanda; Tian, Hainan; Wang, Shucai; Chen, Jin-Gui

    2015-11-26

    Ethylene regulates many aspects of plant growth and development including seed germination, leaf senescence, and fruit ripening, and of plant responses to environmental stimuli including both biotic and abiotic stresses. Ethylene response factors (ERFs) are plant-specific transcription factors and are a subfamily of the AP2 (APETALA2)/ERF transcription factor family. The function of many members in this large gene family remains largely unknown. ERF96, a member of the Group IX ERF family transcription factors, has recently been shown to be a transcriptional activator that is involved in plant defense response in Arabidopsis. In this article, we provide evidence that ERF96 ismore » a positive regulator of abscisic acid (ABA) responses. Bioinformatics analysis indicated that there are a total four small ERFs in Arabidopsis including ERF95, ERF96, ERF97, and ERF98, and that ERF96 forms a cluster with ERF95 and ERF97. By using quantitative RT-PCR, we found that ERF96 is expressed in all tissues and organs examined except roots, with relatively high expression in flowers and seeds. Results from the protoplast transfection assay indicated that the EDLL motif-containing C-terminal domain is responsible for ERF96’s transcriptional activity. Although loss-of-function mutant of ERF96 was morphologically similar to wild type plants, transgenic plants overexpressing ERF96 had smaller rosette size and were delayed in flowering time. In ABA sensitivity assays, we found that ERF96 overexpression plants were hypersensitive to ABA in terms of ABA inhibition of seed germination, early seedling development and root elongation. Consistent with these observations, elevated transcript levels of some ABA-responsive genes including RD29A, ABI5, ABF3, ABF4, P5CS, and COR15A were observed in the transgenic plants in the presence of ABA. However, in the absence of ABA treatment, the transcript levels of these ABA-responsive genes remained largely unchanged. Our experiments also showed

  6. The Small Ethylene Response Factor ERF96 is Involved in the Regulation of the Abscisic Acid Response in Arabidopsis

    SciTech Connect

    Wang, Xiaoping; Liu, Shanda; Tian, Hainan; Wang, Shucai; Chen, Jin-Gui

    2015-11-26

    Ethylene regulates many aspects of plant growth and development including seed germination, leaf senescence, and fruit ripening, and of plant responses to environmental stimuli including both biotic and abiotic stresses. Ethylene response factors (ERFs) are plant-specific transcription factors and are a subfamily of the AP2 (APETALA2)/ERF transcription factor family. The function of many members in this large gene family remains largely unknown. ERF96, a member of the Group IX ERF family transcription factors, has recently been shown to be a transcriptional activator that is involved in plant defense response in Arabidopsis. In this article, we provide evidence that ERF96 is a positive regulator of abscisic acid (ABA) responses. Bioinformatics analysis indicated that there are a total four small ERFs in Arabidopsis including ERF95, ERF96, ERF97, and ERF98, and that ERF96 forms a cluster with ERF95 and ERF97. By using quantitative RT-PCR, we found that ERF96 is expressed in all tissues and organs examined except roots, with relatively high expression in flowers and seeds. Results from the protoplast transfection assay indicated that the EDLL motif-containing C-terminal domain is responsible for ERF96’s transcriptional activity. Although loss-of-function mutant of ERF96 was morphologically similar to wild type plants, transgenic plants overexpressing ERF96 had smaller rosette size and were delayed in flowering time. In ABA sensitivity assays, we found that ERF96 overexpression plants were hypersensitive to ABA in terms of ABA inhibition of seed germination, early seedling development and root elongation. Consistent with these observations, elevated transcript levels of some ABA-responsive genes including RD29A, ABI5, ABF3, ABF4, P5CS, and COR15A were observed in the transgenic plants in the presence of ABA. However, in the absence of ABA treatment, the transcript levels of these ABA-responsive genes remained largely unchanged. Our experiments also showed that water

  7. The Small Ethylene Response Factor ERF96 is Involved in the Regulation of the Abscisic Acid Response in Arabidopsis

    SciTech Connect

    Wang, Xiaoping; Liu, Shanda; Tian, Hainan; Wang, Shucai; Chen, Jin-Gui

    2015-11-26

    We report that ethylene regulates many aspects of plant growth and development including seed germination, leaf senescence, and fruit ripening, and of plant responses to environmental stimuli including both biotic and abiotic stresses. Ethylene response factors (ERFs) are plant-specific transcription factors and are a subfamily of the AP2 (APETALA2)/ERF transcription factor family. The function of many members in this large gene family remains largely unknown. ERF96, a member of the Group IX ERF family transcription factors, has recently been shown to be a transcriptional activator that is involved in plant defense response in Arabidopsis. Here we provide evidence that ERF96 is a positive regulator of abscisic acid (ABA) responses. Bioinformatics analysis indicated that there are a total four small ERFs in Arabidopsis including ERF95, ERF96, ERF97, and ERF98, and that ERF96 forms a cluster with ERF95 and ERF97. By using quantitative RT-PCR, we found that ERF96 is expressed in all tissues and organs examined except roots, with relatively high expression in flowers and seeds. Results from the protoplast transfection assay indicated that the EDLL motif-containing C-terminal domain is responsible for ERF96’s transcriptional activity. Although loss-of-function mutant of ERF96 was morphologically similar to wild type plants, transgenic plants overexpressing ERF96 had smaller rosette size and were delayed in flowering time. In ABA sensitivity assays, we found that ERF96 overexpression plants were hypersensitive to ABA in terms of ABA inhibition of seed germination, early seedling development and root elongation. Consistent with these observations, elevated transcript levels of some ABA-responsive genes including RD29A, ABI5, ABF3, ABF4, P5CS, and COR15A were observed in the transgenic plants in the presence of ABA. However, in the absence of ABA treatment, the transcript levels of these ABA-responsive genes remained largely unchanged. Our experiments also showed that

  8. A new ferulic acid ester, a new ellagic acid derivative, and other constituents from pachycentria formosana: effects on neutrophil pro-inflammatory responses.

    PubMed

    Cho, Jui-Ying; Lee, Tzong-Huei; Hwang, Tsong-Long; Yang, Sheng-Zehn; Chen, Ih-Sheng; Chou, Tsung-Hsien; Sung, Ping-Jyun; Chen, Jih-Jung

    2011-09-01

    A new ferulic acid ester derivative, tetracosane-1,24-diyl di[(Z)-ferulate] (1), and a new ellagic acid derivative, 3,4 : 3',4'-bis(O,O-methylene)ellagic acid (2), have been isolated from leaves and twigs of Pachycentria formosana, together with eight known compounds. Their structures were determined by in-depth spectroscopic and mass-spectrometric analyses. Among the isolated compounds, oleanolic acid (6), ursolic acid acetate (7), and 3-epibetulinic acid (9) exhibited potent inhibition (IC(50) values ≤ 21.8 μM) of O₂(-) generation by human neutrophils in response to N-formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB). In addition, oleanolic acid (6), 3-O-[(E)-feruloyl]ursolic acid (8), 3-epibetulinic acid (9), and lawsonic acid (10) also inhibited fMLP/CB-induced elastase release with IC(50) values ≤ 18.6 μM. PMID:21922659

  9. Sialic acids in different Leishmania sp., its correlation with nitric oxide resistance and host responses.

    PubMed

    Ghoshal, Angana; Gerwig, Gerrit J; Kamerling, Johannis P; Mandal, Chitra

    2010-05-01

    The presence of different derivatives of sialic acids (SA) on Leishmania donovani instigated us to investigate their status on different strains of Leishmania sp. causing different forms of the disease. Leishmania tropica (K27), Leishmania major (JISH118) and Leishmania mexicana (LV4) responsible for cutaneous, Leishmania braziliensis (L280) and Leishmania amazonensis (LV81) causing diffuse and Leishmania infantum (MON29) responsible for visceral leishmaniasis were included in this study. The strains showed a differential distribution of SA in spite of their close resemblance in pathogenesis. K27, JISH118, L280 and MON29 were categorized as high SA-containing strains having enhanced 9-O-acetyl sialic acid (9-O-AcSA(high)) whereas LV4 and LV81 evidenced considerably reduced SA. Interestingly, 9-O-AcSA(high) promastigotes showed significant viability as compared to their de-O-acetylated forms after exposure to NaNO(2) suggesting the involvement of 9-O-AcSA in conferring nitric oxide (NO) resistance. Enhanced intracellular survivability was demonstrated following infection of human macrophages with 9-O-AcSA(high) promastigotes in contrast to their de-O-acetylated forms indicating their contribution in bestowing a survival benefit. Additionally, reduced accumulation of NO, interleukin-12 and interferon-gamma in the supernatant of macrophages infected with 9-O-AcSA(high) promastigotes indicated suppression of leishmanicidal host responses. However, LV4 and LV81 with least 9-O-AcSA, before and after de-O-acetylation, showed unaltered NO resistance, multiplicity and host responses signifying the probable involvement of other determinants which may be a function of their inherent parasitic attribute. Hence, enhanced levels of 9-O-AcSA serve as one of the potential determinants responsible for increased NO resistance and survivability of parasites by inhibition of host responses. PMID:20085901

  10. Thermo-responsive behavior of borinic acid polymers: experimental and molecular dynamics studies.

    PubMed

    Wan, Wen-Ming; Zhou, Peng; Cheng, Fei; Sun, Xiao-Li; Lv, Xin-Hu; Li, Kang-Kang; Xu, Hai; Sun, Miao; Jäkle, Frieder

    2015-09-28

    The thermo-responsive properties of borinic acid polymers were investigated by experimental and molecular dynamics simulation studies. The homopolymer poly(styrylphenyl(tri-iso-propylphenyl)borinic acid) (PBA) exhibits an upper critical solution temperature (UCST) in polar organic solvents that is tunable over a wide temperature range by addition of small amounts of H2O. The UCST of a 1 mg mL(-1) PBA solution in DMSO can be adjusted from 20 to 100 °C by varying the H2O content from ∼0-2.5%, in DMF from 0 to 100 °C (∼3-17% H2O content), and in THF from 0 to 60 °C (∼4-19% H2O). The UCST increases almost linearly from the freezing point of the solvent with higher freezing point to the boiling point of the solvent with the lower boiling point. The mechanistic aspects of this process were investigated by molecular dynamics simulations. The latter indicate rapid and strong hydrogen-bond formation between BOH moieties and H2O molecules, which serve as crosslinkers to form an insoluble network. Our results suggest that borinic acid-containing polymers are promising as new "smart" materials, which display thermo-responsive properties that are tunable over a wide temperature range. PMID:26256052

  11. Stimuli responsive charge-switchable lipids: Capture and release of nucleic acids.

    PubMed

    Hersey, Joseph S; LaManna, Caroline M; Lusic, Hrvoje; Grinstaff, Mark W

    2016-03-01

    Stimuli responsive lipids, which enable control over the formation, transformation, and disruption of supramolecular assemblies, are of interest for biosensing, diagnostics, drug delivery, and basic transmembrane protein studies. In particular, spatiotemporal control over a supramolecular structure can be achieved using light activated compounds to induce significant supramolecular rearrangements. As such, a family of cationic lipids are described which undergo a permanent switch in charge upon exposure to 365 nm ultraviolet (UV) light to enable the capture of negatively charged nucleic acids within the self-assembled supramolecular structure of the lipids and subsequent release of these macromolecules upon exposure to UV light and disruption of the assemblies. The lipids are composed of either two different tripeptide head groups, Lysine-Glycine-Glycine (KGG) and Glycine-Glycine-Glycine (GGG) and three different hydrocarbon chain lengths (C6, C10, or C14) terminated by a UV light responsive 1-(2-nitrophenyl)ethanol (NPE) protected carboxylic acid. The photolysis of the NPE protected lipid is measured as a function of time, and the resulting changes in net molecular charge are observed using zeta potential analysis for each head group and chain length combination. A proof of concept study for the capture and release of both linear DNA (calf thymus) and siRNA is presented using an ethidium bromide quenching assay where a balance between binding affinity and supramolecular stability are found to be the key to optimal nucleic acid capture and release. PMID:26896839

  12. Free fatty acids sensitize dendritic cells to amplify TH1/TH17-immune responses.

    PubMed

    Stelzner, Kristin; Herbert, Diana; Popkova, Yulia; Lorz, Axel; Schiller, Jürgen; Gericke, Martin; Klöting, Nora; Blüher, Matthias; Franz, Sandra; Simon, Jan C; Saalbach, Anja

    2016-08-01

    Obesity is associated with body fat gain and impaired glucose metabolism. Here, we identified both body fat gain in obesity and impaired glucose metabolism as two independent risk factors for increased serum levels of free fatty acids (FFAs). Since obesity is associated with increased and/or delayed resolution of inflammation observed in various chronic inflammatory diseases such as psoriasis, we investigated the impact of FFAs on human monocyte-derived and mouse bone marrow-derived dendritic cell (DCs) functions relevant for the pathogenesis of chronic inflammation. FFAs such as palmitic acid (PA) and oleic acid (OA) did not affect the pro-inflammatory immune response of DCs. In contrast, PA and OA sensitize DCs resulting in augmented secretion of TH1/TH17-instructive cytokines upon pro-inflammatory stimulation. Interestingly, obesity in mice worsened a TH1/TH17-driven psoriasis-like skin inflammation. Strong correlation of the amount of total FFA, PA, and OA in serum with the severity of skin inflammation points to a critical role of FFA in obesity-mediated exacerbation of skin inflammation. Our data suggest that increased levels of FFAs might be a predisposing factor promoting a TH1/TH17-mediated inflammation such as psoriasis in response to an inflammatory danger signal. PMID:27214608

  13. Seed Dormancy and Responses of Caryopses, Embryos, and Calli to Abscisic Acid in Wheat 1

    PubMed Central

    Morris, C. F.; Moffatt, J. M.; Sears, R. G.; Paulsen, G. M.

    1989-01-01

    Preharvest sprouting of wheat (Triticum aestivum L.) is associated with inadequate seed dormancy. Although abscisic acid (ABA) has often been suggested to play a central role in developing seed, its involvement in dormancy of mature seed lacks firm experimental evidence and endogenous ABA levels are not well correlated with germinability. We examined genotypic and temporal variation in wheat seed and embryo germination responses to ABA and determined whether differential sensitivity of embryos to ABA extended to growth of embryo-derived calli. Germination of Parker 76 caryopses, which have little dormancy at maturity, was only slightly inhibited by ABA, whereas germination of Clark's Cream, a highly dormant genotype, was greatly inhibited. Responsiveness of caryopses to ABA and dormancy of seeds decreased concurrently during afterripening. Germination of embryos excised from dormant and nondormant seeds was more responsive to ABA but otherwise was similar to that of caryopses, indicating that differential response to ABA occurs in the embryo. Growth of calli derived from immature embryos of two sprouting-susceptible wheat genotypes exceeded growth of calli from Clark's Cream, but no distinct differences in response to ABA among the genotypes were apparent. We concluded that the action of ABA is similar in developing and mature seeds, that genotypic and temporal variation in embryo responsiveness to endogenous ABA may be involved in dormancy, and that ABA probably acts in concert with other endogenous constituents. PMID:16666821

  14. Open Stomata 1 (OST1) is limiting in abscisic acid responses of Arabidopsis guard cells.

    PubMed

    Acharya, Biswa R; Jeon, Byeong Wook; Zhang, Wei; Assmann, Sarah M

    2013-12-01

    Open Stomata 1 (OST1) (SnRK2.6 or SRK2E), a serine/threonine protein kinase, is a positive regulator in abscisic acid (ABA)-mediated stomatal response, but OST1-regulation of K(+) and Ca(2+) currents has not been studied directly in guard cells and it is unknown whether OST1 activity is limiting in ABA-mediated stomatal responses. We employed loss-of-function and gain-of-function approaches to study native ABA responses of Arabidopsis guard cells. We performed stomatal aperture bioassays, patch clamp analyses and reactive oxygen species (ROS) measurements. ABA inhibition of inward K(+) channels and light-induced stomatal opening are reduced in ost1 mutants while transgenic plants overexpressing OST1 show ABA hypersensitivity in these responses. ost1 mutants are insensitive to ABA-induced stomatal closure, regulation of slow anion currents, Ca(2+) -permeable channel activation and ROS production while OST1 overexpressing lines are hypersensitive for these responses, resulting in accelerated stomatal closure in response to ABA. Overexpression of OST1 in planta in the absence of ABA application does not affect basal apertures or ion currents. Moreover, we demonstrate the physical interaction of OST1 with the inward K(+) channel KAT1, the anion channel SLAC1, and the NADPH oxidases AtrbohD and AtrbohF. Our findings support OST1 as a critical limiting component in ABA regulation of stomatal apertures, ion channels and NADPH oxidases in Arabidopsis guard cells. PMID:24033256

  15. Amino Acid PET – An Imaging Option to Identify Treatment Response, Posttherapeutic Effects, and Tumor Recurrence?

    PubMed Central

    Galldiks, Norbert; Langen, Karl-Josef

    2016-01-01

    Routine diagnostics and treatment monitoring in patients with primary and secondary brain tumors is usually based on contrast-enhanced standard MRI. However, the capacity of standard MRI to differentiate neoplastic tissue from non-specific posttreatment effects may be limited particularly after therapeutic interventions such as radio- and/or chemotherapy or newer treatment options, e.g., immune therapy. Metabolic imaging using PET may provide relevant additional information on tumor metabolism, which allows a more accurate diagnosis especially in clinically equivocal situations, particularly when radiolabeled amino acids are used. Amino acid PET allows a sensitive monitoring of a response to various treatment options, the early detection of tumor recurrence, and an improved differentiation of tumor recurrence from posttherapeutic effects. In the past, this method had only limited availability due to the use of PET tracers with a short half-life, e.g., C-11. In recent years, however, novel amino acid PET tracers labeled with positron emitters with a longer half-life (F-18) have been developed and clinically validated, which allow a more efficient and cost-effective application. These developments and the well-documented diagnostic performance of PET using radiolabeled amino acids suggest that its application continues to spread and that this technique may be available as a routine diagnostic tool for several indications in the field of neuro-oncology. PMID:27516754

  16. In vitro pollen responses of two birch species to acidity and temperature

    SciTech Connect

    Hughes, R.N.; Cox, R.M.

    1993-10-01

    Paper birch (Betula papyrifera Marsh.) and mountain paper birch (Betula cordifolia Regel) near the Bay of Fundy coast frequently intercept acidic advection marine fogs. Chemical deposition by these fogs is thought to be a factor contributing to the observed foliar browning symptoms associated with a marked deterioration of these trees in the area. In vitro experiments were performed to test whether pollen germination in these two birch species would be affected by acidity at levels routinely found in the fog. The combined effect of temperature with acidity was also examined. Pollen germination in both species was inhibited below pH 5.6 (P < 0.0001) and the effect of incubation temperature was also significant (P < 0.01) in both species. There was no difference in in vitro pollen germination between species (P > 0.05) in response to acidity, based on combined data from 12 trees of each; the optimum germination temperature was 22{degrees}C for B. papyrifera and 21{degrees}C for B. cordifolia.

  17. Synthesis and characterization of a pH responsive folic acid functionalized polymeric drug delivery system.

    PubMed

    Li, Xia; McTaggart, Matt; Malardier-Jugroot, Cecile

    2016-01-01

    We report the computational analysis, synthesis and characterization of folate functionalized poly(styrene-alt-maleic anhydride), PSMA for drug delivery purpose. The selection of the proper linker between the polymer and the folic acid group was performed before conducting the synthesis using Density Functional Theory (DFT). The computational results showed the bio-degradable linker 2, 4-diaminobutyric acid, DABA as a good candidate allowing flexibility of the folic acid group while maintaining the pH sensitivity of PSMA, used as a trigger for drug release. The synthesis was subsequently carried out in multi-step experimental procedures. The functionalized polymer was characterized using InfraRed spectroscopy, Nuclear Magnetic Resonance and Dynamic Light Scattering confirming both the chemical structure and the pH responsiveness of PSMA-DABA-Folate polymers. This study provides an excellent example of how computational chemistry can be used in selection process for the functional materials and product characterization. The pH sensitive polymers are expected to be used in delivering anti-cancer drugs to solid tumors with overly expressed folic acid receptors. PMID:27183249

  18. Surviving the acid barrier: responses of pathogenic Vibrio cholerae to simulated gastric fluid.

    PubMed

    Singh, Atheesha; Barnard, Tobias G

    2016-01-01

    When bacteria are subjected to low acidic pHs of the gastric environment, they may enter the viable but nonculturable (VBNC) state of survival. In this state, bacteria cannot be cultured on solid media, still exhibit signs of metabolic activity (viability). In this study, the response of pathogenic Vibrio cholerae O1 and O139 to low pH-simulated environments of the human stomach was evaluated for their survival by culturability (plate count) and viability (flow cytometry-FC) assays. Bacteria were acid challenged with simulated gastric fluid (SGF) at pH 1.5, 2.5, 3.5 and 4.5 over a period of 180 min. Exposure to SGF up to 120 min increased acid tolerance of the Vibrios up to pH 3.5 with acid challenge occurring at pH 4.5. Bacteria were culturable from pH 2.5 to 4.5 up to 60 min SGF exposure. The stationary-phase cultures of Vibrio were able to survive SGF at all pHs in an 'injured' state with FC. This could possibly mean that the bacteria have entered the VBNC stage of survival. This is a worrying public health concern due to the fact that once favourable conditions arise (intestines), these Vibrios can change back to an infectious state and cause disease. PMID:26496916

  19. Dose-dependent transitions in Nrf2-mediated adaptive response and related stress responses to hypochlorous acid in mouse macrophages

    SciTech Connect

    Woods, Courtney G.; Fu Jingqi; Xue Peng; Hou Yongyong; Pluta, Linda J.; Yang Longlong; Zhang Qiang; Thomas, Russell S.; Andersen, Melvin E.; Pi Jingbo

    2009-07-01

    Hypochlorous acid (HOCl) is potentially an important source of cellular oxidative stress. Human HOCl exposure can occur from chlorine gas inhalation or from endogenous sources of HOCl, such as respiratory burst by phagocytes. Transcription factor Nrf2 is a key regulator of cellular redox status and serves as a primary source of defense against oxidative stress. We recently demonstrated that HOCl activates Nrf2-mediated antioxidant response in cultured mouse macrophages in a biphasic manner. In an effort to determine whether Nrf2 pathways overlap with other stress pathways, gene expression profiling was performed in RAW 264.7 macrophages exposed to HOCl using whole genome mouse microarrays. Benchmark dose (BMD) analysis on gene expression data revealed that Nrf2-mediated antioxidant response and protein ubiquitination were the most sensitive biological pathways that were activated in response to low concentrations of HOCl (< 0.35 mM). Genes involved in chromatin architecture maintenance and DNA-dependent transcription were also sensitive to very low doses. Moderate concentrations of HOCl (0.35 to 1.4 mM) caused maximal activation of the Nrf2 pathway and innate immune response genes, such as IL-1{beta}, IL-6, IL-10 and chemokines. At even higher concentrations of HOCl (2.8 to 3.5 mM) there was a loss of Nrf2-target gene expression with increased expression of numerous heat shock and histone cluster genes, AP-1-family genes, cFos and Fra1 and DNA damage-inducible Gadd45 genes. These findings confirm an Nrf2-centric mechanism of action of HOCl in mouse macrophages and provide evidence of interactions between Nrf2, inflammatory, and other stress pathways.

  20. Glutathione-mediated response to acid stress in the probiotic bacterium, Lactobacillus salivarius.

    PubMed

    Lee, Kibeom; Pi, Kyungbae; Kim, Eun Bae; Rho, Beom-Seop; Kang, Sang-Kee; Lee, Hong Gu; Choi, Yun-Jaie

    2010-07-01

    Lactobacillus salivarius, a probiotic bacterium, encounters acidic conditions in its passage through the gastrointestinal tract of human and animal hosts. We studied the effect of a rapid downshift in extracellular pH from 6.5 to 4 on cell growth. The maximum growth rate was higher in low pH medium with glutathione supplementation than without. Cells developed a GSH-mediated acid-tolerance response and, when grown with 0.5 mM GSH, reached a higher final density than with other conditions. These findings suggest that the increased growth rate is caused by uptake of GSH which acts as a nutrient source as well as having protective functions, allowing for continued growth. PMID:20349113

  1. Respiratory responses to laboratory-generation acid fog in healthy and asthmatic volunteers

    SciTech Connect

    Avol, E.L.; Linn, W.S.; Hackney, J.D. )

    1987-01-01

    The authors discuss a program to provide a first step towards assessing acute health-related effects of acid fog exposure. Polluted ambient fog was simulated in a laboratory exposure chamber. Volunteer subjects were purposely exposed and studied during periods of exercise and rest while in the challenge atmosphere. Respiratory responses were measured by methods used to assess effects of irritant gases and dry'' respirable aerosols. When a pilot study showed no obvious unfavorable effects with ambient-like pollution conditions, the exposure concentrations for the present study were extended into the occupational range, well above ambient levels. Sulfuric acid was selected for use as the test pollutant, based upon previous research experience and the availability of fog data documenting its presence during ambient fog episodes.

  2. Very long chain fatty acid and lipid signaling in the response of plants to pathogens

    PubMed Central

    Raffaele, Sylvain; Leger, Amandine

    2009-01-01

    Recent findings indicate that lipid signaling is essential for plant resistance to pathogens. Besides oxylipins and unsaturated fatty acids known to play important signaling functions during plant-pathogen interactions, the very long chain fatty acid (VLCFA) biosynthesis pathway has been recently associated to plant defense through different aspects. VLCFAs are indeed required for the biosynthesis of the plant cuticle and the generation of sphingolipids. Elucidation of the roles of these lipids in biotic stress responses is the result of the use of genetic approaches together with the identification of the genes/proteins involved in their biosynthesis. This review focuses on recent observations which revealed the complex function of the cuticle and cuticle-derived signals, and the key role of sphingolipids as bioactive molecules involved in signal transduction and cell death regulation during plant-pathogen interactions. PMID:19649180

  3. Stability studies of ascorbic acid 2-glucoside in cosmetic lotion using surface response methodology.

    PubMed

    Huang, Wen-Ying; Lee, Pei-Chi; Huang, Ling-Kuei; Lu, Li-Ping; Liao, Wayne C

    2013-03-15

    Ascorbic acid 2-glucoside (AA-2G) has been widely used in cream and lotion types of cosmetic products. Thus, the degradation of AA-2G caused by the temperature change and pH variation was very critical for determining the bio-functionality of cosmetics. Response surface methodology (RSM) was introduced to study the influence of temperature and pH on the stability of AA-2G. The optimal condition of retaining AA-2G with the highest stability was determined to be 55.3°C and pH 6.4. The antioxidative activities of AA-2G including DPPH and ABTS free radical scavenging activities, metal chelating activity, and reducing ability were also determined. AA-2G was a good ascorbic acid derivative which could be used in cosmetic products as an active ingredient. PMID:23416010

  4. Refocusing of B-cell responses following a single amino acid substitution in an antigen

    PubMed Central

    Chiesa, Marta Dalla; Martensen, Pia M; Simmons, Cameron; Porakishvili, Nino; Justesen, Just; Dougan, Gordon; Roitt, Ivan M; Delves, Peter J; Lund, Torben

    2001-01-01

    Intranasal immunization of BALB/c strain mice was carried out using baculovirus-derived human chorionic gonadotrophin (hCG) β-chain, together with Escherichia coli heat-labile enterotoxin. Gonadotrophin-reactive immunoglobulin A (IgA) was induced in a remote mucosal site, the lung, in addition to a systemic IgG response. The extensive sequence homology with luteinizing hormone (LH) results in the production of LH cross-reactive antibodies when holo-hCG is used as an immunogen. In contrast to wild-type hCGβ, a mutated hCGβ-chain containing an arginine to glutamic acid substitution at position 68 did not induce the production of antibodies which cross-react with LH. Furthermore, the epitopes utilized in the B-cell response to the mutated hCGβ shifted away from the immunodominant region of the parent wild-type molecule towards epitopes within the normally weakly immunogenic C terminus. This shift in epitope usage was also seen following intramuscular immunization of rabbits. Thus, a single amino acid change, which does not disrupt the overall structure of the molecule, refocuses the immune response away from a disadvantageous cross-reactive epitope region and towards a normally weakly immunogenic but antigen-unique area. Similar mutational strategies for epitope-refocusing may be applicable to other vaccine candidate molecules. PMID:11412304

  5. Pseudomonas putida response in membrane bioreactors under salicylic acid-induced stress conditions.

    PubMed

    Collado, Sergio; Rosas, Irene; González, Elena; Gutierrez-Lavin, Antonio; Diaz, Mario

    2014-02-28

    Starvation and changing feeding conditions are frequently characteristics of wastewater treatment plants. They are typical causes of unsteady-state operation of biological systems and provoke cellular stress. The response of a membrane bioreactor functioning under feed-induced stress conditions is studied here. In order to simplify and considerably amplify the response to stress and to obtain a reference model, a pure culture of Pseudomonas putida was selected instead of an activated sludge and a sole substrate (salicylic acid) was employed. The system degraded salicylic acid at 100-1100mg/L with a high level of efficiency, showed rapid acclimation without substrate or product inhibition phenomena and good stability in response to unsteady states caused by feed variations. Under starvation conditions, specific degradation rates of around 15mg/gh were achieved during the adaptation of the biomass to the new conditions and no biofilm formation was observed during the first days of experimentation using an initial substrate to microorganisms ratio lower than 0.1. When substrate was added to the reactor as pulses resulting in rapidly changing concentrations, P. putida growth was observed only for substrate to microorganism ratios higher than 0.6, with a maximum YX/S of 0.5g/g. Biofilm development under changing feeding conditions was fast, biomass detachment only being significant for biomass concentrations on the membrane surface that were higher than 16g/m(2). PMID:24413046

  6. Oleic acid content of a meal promotes oleoylethanolamide response and reduces subsequent energy intake in humans.

    PubMed

    Mennella, Ilario; Savarese, Maria; Ferracane, Rosalia; Sacchi, Raffaele; Vitaglione, Paola

    2015-01-01

    Animal data suggest that dietary fat composition may influence endocannabinoid (EC) response and dietary behavior. This study tested the hypothesis that fatty acid composition of a meal can influence the short-term response of ECs and subsequent energy intake in humans. Fifteen volunteers on three occasions were randomly offered a meal containing 30 g of bread and 30 mL of one of three selected oils: sunflower oil (SO), high oleic sunflower oil (HOSO) and virgin olive oil (VOO). Plasma EC concentrations and appetite ratings over 2 h and energy intake over 24 h following the experimental meal were measured. Results showed that after HOSO and VOO consumption the circulating oleoylethanolamide (OEA) was significantly higher than after SO consumption; a concomitantly significant reduction of energy intake was found. For the first time the oleic acid content of a meal was demonstrated to increase the post-prandial response of circulating OEA and to reduce energy intake at subsequent meals in humans. PMID:25347552

  7. Bile Acids Repress Hypoxia-Inducible Factor 1 Signaling and Modulate the Airway Immune Response

    PubMed Central

    Legendre, Claire; Reen, F. Jerry; Woods, David F.; Mooij, Marlies J.; Adams, Claire

    2014-01-01

    Gastroesophageal reflux (GER) frequently occurs in patients with respiratory disease and is particularly prevalent in patients with cystic fibrosis. GER is a condition in which the duodenogastric contents of the stomach leak into the esophagus, in many cases resulting in aspiration into the respiratory tract. As such, the presence of GER-derived bile acids (BAs) has been confirmed in the bronchoalveolar lavage fluid and sputum of affected patients. We have recently shown that bile causes cystic fibrosis-associated bacterial pathogens to adopt a chronic lifestyle and may constitute a major host trigger underlying respiratory infection. The current study shows that BAs elicit a specific response in humans in which they repress hypoxia-inducible factor 1α (HIF-1α) protein, an emerging master regulator in response to infection and inflammation. HIF-1α repression was shown to occur through the 26S proteasome machinery via the prolyl hydroxylase domain (PHD) pathway. Further analysis of the downstream inflammatory response showed that HIF-1α repression by BAs can significantly modulate the immune response of airway epithelial cells, correlating with a decrease in interleukin-8 (IL-8) production, while IL-6 production was strongly increased. Importantly, the effects of BAs on cytokine production can also be more dominant than the bacterium-mediated effects. However, the effect of BAs on cytokine levels cannot be fully explained by their ability to repress HIF-1α, which is not surprising, given the complexity of the immune regulatory network. The suppression of HIF-1 signaling by bile acids may have a significant influence on the progression and outcome of respiratory disease, and the molecular mechanism underpinning this response warrants further investigation. PMID:24914220

  8. Attenuated acute salivary α-amylase responses to gustatory stimulation with citric acid in thin children.

    PubMed

    Chen, Long Hui; Yang, Ze Min; Chen, Wei Wen; Lin, Jing; Zhang, Min; Yang, Xiao Rong; Zhao, Ling Bo

    2015-04-14

    Salivary α-amylase (sAA) is responsible for the 'pre-digestion' of starch in the oral cavity and accounts for up to 50 % of salivary protein in human saliva. An accumulating body of literature suggests that sAA is of nutritional importance; however, it is still not clear how sAA is related to individual's nutritional status. Although copy number variations (CNV) of the salivary amylase gene (AMY1) are associated with variation in sAA levels, a significant amount of sAA variation is not explained by AMY1 CNV. To measure sAA responses to gustatory stimulation with citric acid, we used sAA ratio (the ratio of stimulated sAA levels to those of resting sAA) and investigated acute sAA responses to citric acid in children with normal (Normal-BMI, n 22) and low (Low-BMI, n 21) BMI. The AMY1 gene copy number was determined by quantitative PCR. We, for the first time, demonstrated attenuated acute sAA responses (decreased sAA ratio) to gustatory stimulation in Low-BMI (thinness grade 3) children compared with the Normal-BMI children, which suggest that sAA responses to gustatory stimulation may be of nutritional importance. However, child's nutritional status was not directly related to their resting or stimulated sAA levels, and it was not associated with AMY1 gene copy number. Finally, AMY1 CNV might influence, but did not eventually determine, sAA levels in children. PMID:25784372

  9. Chlorogenic acid differentially affects postprandial glucose and glucose-dependent insulinotropic polypeptide response in rats.

    PubMed

    Tunnicliffe, Jasmine M; Eller, Lindsay K; Reimer, Raylene A; Hittel, Dustin S; Shearer, Jane

    2011-10-01

    Regular coffee consumption significantly lowers the risk of type 2 diabetes (T2D). Coffee contains thousands of compounds; however, the specific component(s) responsible for this reduced risk is unknown. Chlorogenic acids (CGA) found in brewed coffee inhibit intestinal glucose uptake in vitro. The objective of this study was to elucidate the mechanisms by which CGA acts to mediate blood glucose response in vivo. Conscious, unrestrained, male Sprague-Dawley rats were chronically catheterized and gavage-fed a standardized meal (59% carbohydrate, 25% fat, 12% protein), administered with or without CGA (120 mg·kg(-1)), in a randomized crossover design separated by a 3-day washout period. Acetaminophen was co-administered to assess the effects of CGA on gastric emptying. The incretins glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) were measured. GLP-1 response in the presence of glucose and CGA was further examined, using the human colon cell line NCI-H716. Total area under the curve (AUC) for blood glucose was significantly attenuated in rats fed CGA (p < 0.05). Despite this, no differences in plasma insulin or nonesterified fatty acids were observed, and gastric emptying was not altered. Plasma GIP response was blunted in rats fed CGA, with a lower peak concentration and AUC up to 180 min postprandially (p < 0.05). There were no changes in GLP-1 secretion in either the in vivo or in vitro study. In conclusion, CGA treatment resulted in beneficial effects on blood glucose response, with alterations seen in GIP concentrations. Given the widespread consumption and availability of coffee, CGA may be a viable prevention tool for T2D. PMID:21977912

  10. Docosahexaenoic Acid Ameliorates Fructose-Induced Hepatic Steatosis Involving ER Stress Response in Primary Mouse Hepatocytes

    PubMed Central

    Zheng, Jinying; Peng, Chuan; Ai, Yanbiao; Wang, Heng; Xiao, Xiaoqiu; Li, Jibin

    2016-01-01

    The increase in fructose consumption is considered to be a risk factor for developing nonalcoholic fatty liver disease (NAFLD). We investigated the effects of docosahexaenoic acid (DHA) on hepatic lipid metabolism in fructose-treated primary mouse hepatocytes, and the changes of Endoplasmic reticulum (ER) stress pathways in response to DHA treatment. The hepatocytes were treated with fructose, DHA, fructose plus DHA, tunicamycin (TM) or fructose plus 4-phenylbutyric acid (PBA) for 24 h. Intracellular triglyceride (TG) accumulation was assessed by Oil Red O staining. The mRNA expression levels and protein levels related to lipid metabolism and ER stress response were determined by real-time PCR and Western blot. Fructose treatment led to obvious TG accumulation in primary hepatocytes through increasing expression of fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC), two key enzymes in hepatic de novo lipogenesis. DHA ameliorates fructose-induced TG accumulation by upregulating the expression of carnitine palmitoyltransferase 1A (CPT-1α) and acyl-CoA oxidase 1 (ACOX1). DHA treatment or pretreatment with the ER stress inhibitor PBA significantly decreased TG accumulation and reduced the expression of glucose-regulated protein 78 (GRP78), total inositol-requiring kinase 1 (IRE1α) and p-IRE1α. The present results suggest that DHA protects against high fructose-induced hepatocellular lipid accumulation. The current findings also suggest that alleviating the ER stress response seems to play a role in the prevention of fructose-induced hepatic steatosis by DHA. PMID:26805874

  11. Renal cortex taurine content regulates renal adaptive response to altered dietary intake of sulfur amino acids.

    PubMed Central

    Chesney, R W; Gusowski, N; Dabbagh, S

    1985-01-01

    Rats fed a reduced sulfur amino acid diet (LTD) or a high-taurine diet (HTD) demonstrate a renal adaptive response. The LTD results in hypotaurinuria and enhanced brush border membrane vesicle (BBMV) accumulation of taurine. The HTD causes hypertaurinuria and reduced BBMV uptake. This adaptation may relate to changes in plasma or renal cortex taurine concentration. Rats were fed a normal-taurine diet (NTD), LTD, or HTD for 14 d or they underwent: (a) 3% beta-alanine for the last 8 d of each diet; (b) 3 d of fasting; or (c) a combination of 3% beta-alanine added for 8 d and 3 d of fasting. Each maneuver lowered the cortex taurine concentration, but did not significantly lower plasma taurine values compared with controls. Increased BBMV taurine uptake occurred after each manipulation. Feeding 3% glycine did not alter the plasma, renal cortex, or urinary taurine concentrations, or BBMV uptake of taurine. Feeding 3% methionine raised plasma and urinary taurine excretion but renal tissue taurine was unchanged, as was initial BBMV uptake. Hence, nonsulfur-containing alpha-amino acids did not change beta-amino acid transport. The increase in BBMV uptake correlates with the decline in renal cortex and plasma taurine content. However, since 3% methionine changed plasma taurine without altering BBMV uptake, it is more likely that the change in BBMV uptake and the adaptive response expressed at the brush border surface relate to changes in renal cortex taurine concentrations. Finally, despite changes in urine and renal cortex taurine content, brain taurine values were unchanged, which suggests that this renal adaptive response maintains stable taurine concentrations where taurine serves as a neuromodulator. PMID:3935668

  12. Effect of Warm-Up on Plasma Free Fatty Acid Response and Substrate Utilization During Submaximal Exercise.

    ERIC Educational Resources Information Center

    Hetzler, Ronald K.; And Others

    1986-01-01

    This study examined the effect of preliminary walking on free fatty acid responses and substrate utilization during a 40-minute treadmill run by experienced male distance runners. Conclusions are presented. (Author/MT)

  13. Rhizosphere pH responses to simulated acid rain as measured with glass microelectrodes

    SciTech Connect

    Conkling, B.L.

    1988-01-01

    The objectives of this study were to develop a useful experimental system for studying the rhizosphere of growing roots, and to investigate the effects of bulk soil pH and foliar acid rain application on the rhizosphere pH of alfalfa, corn and soybeans. First, a study was done to compare soil pH measurements made with a standard glass pH electrode with those made using an antimony (Sb) microelectrode. Because of uncertainty with the Sb microelectrodes' response, glass pH-sensitive microelectrodes were made and tested for rhizosphere pH measurements. The influence of soil water pressure gradients in the range of {minus}10 to {minus}1500 kPa in the proximity of the pH and reference electrodes on pH measurements made with microelectrodes was studied. The effect of foliar acid rain application on the rhizosphere pH of alfalfa, corn, and soybean as a function of soil pH were studied. Alfalfa, corn, and soybean were grown into minirhizotrons containing reformed samples of both Seymour A and Bt soil horizons, and the rhizosphere pH measured. The measured in situ bulk soil pH ranged from 4.9 to 6.2 in the A horizon and from 4.0 to 5.7 in the Bt horizon. Plants received acid or non-acid foliar rain applications. Rhizosphere pH was measured using a glass pH-sensitive microelectrode. Acid rain applications caused foliar damage, but had little effect on the rhizosphere pH. The general trend was for the lateral root pH values to be slightly higher than the main root values.

  14. Enhanced Enzymatic Preparation of Biodiesel Using Ricinoleic Acid as Acyl Donor: Optimization Using Response Surface Methodology.

    PubMed

    Wang, Ping; Sun, Shangde

    2016-09-01

    Castor oil methyl ester is a kind of biodiesel from castor oil. However, in those previous methods for biodiesel preparation using castor oil as feedstock, glycerol was the main by-product, which had a strong blocking effect on the immobilized enzyme activity and affected the mass transfer of reaction system. For avoiding the negative effect of glycerol on the enzymatic esterification, biodiesel was prepared using ricinoleic acid (RA) as acyl donor. Enzyme screening was also studied, and the effects of reaction temperature, molar ratio of ricinoleic acid and methanol, enzyme load, and reaction time, on the preparation of castor methyl ester were also evaluated. Response surface methodology (RSM) was used to optimize the interaction effect of reaction variables (reaction temperature (30-70°C), enzyme load (2-7%; relative to the weight of total substrates), molar ratio of methanol to ricinoleic acid (2:1-10:1), and reaction time (0.5-2.5 h)) on the acid value (AV) and the degree of esterification (DE). Validation of the RSM model was verified by the good agreement between the experimental and the predicted values of AV and DE. The optimum preparation conditions were as follows: reaction temperature, 48.2°C; enzyme load, 5.8%; molar ratio of methanol to ricinoleic acid, 5.56:1; reaction time, 2.36 h. Under these conditions, the AV and DE of the esterification reaction are 10.36±1.05 mgKOH/g and 94.03±0.60%, respectively. The relationship between initial reaction rate and temperature was also established, and the activation energy (Ea) of the enzymatic esterification is 33.87 KJ/mol. PMID:27477073

  15. Fibroblast response is enhanced by poly(L-lactic acid) nanotopography edge density and proximity

    PubMed Central

    Milner, Keith R; Siedlecki, Christopher A

    2007-01-01

    The development of scaffolds for use in tissue engineering applications requires careful choice of macroscale properties, such as mechanical characteristics, porosity and biodegradation. The micro- and nano-scale properties of the scaffold surface are also an important design criterion as these influence cell adhesion, proliferation, and differentiation. The cellular response is known to be affected by surface topography but the mechanisms governing this remain unclear. Homogenous poly(L-lactic acid) was textured with surface nanotopographies by two-stage replication molding of heterogeneous demixed polymer films. Initial cell adhesion was improved on nanotextured surfaces compared with smooth controls, but subsequent cell density was significantly reduced on the roughest surfaces. Improvements in cell response were found to correlate with focal contact and actin microfilament development. Cell response was found to trend both with the surface density of topography edges and with inter-topography spacing, indicating possible roles for edges stimulating cell adhesion/proliferation or for spacing to modulate the ability of integrin-ligand bonds to cluster and form focal adhesions. This study furthers understanding of the geometric properties of surface nanotopographies that affect cellular response. It is hoped that identification of the mechanisms governing cell-topography interactions will allow rule-based design of biomaterial surface to engineer specific cellular responses. PMID:17722548

  16. Suppression of the primary IgM response by environmental teichoic acid.

    PubMed

    Oldfather, J W; Chorpenning, F W

    1981-05-01

    It has been shown previously that ingestion of glycerol teichoic acid (GTA) in the conventional laboratory diet (8 mg/kg) is the stimulus for natural background responses to GTA in rats. Since injected GTA suppresses responses to sheep red blood cells (SRBC), it was suspected that dietary GTA also might be acting suppressively. A comparison of rats fed the conventional diet with rats fed a GTA-free diet showed that ingested GTA markedly suppressed immune and background direct plaque-forming cell (PFC) responses to SRBC. It appeared that a direct causal relationship existed between the degree of suppression and the amount of GTA exposure. When GTA-deprived rats were force-fed varying doses of GTA or when conventional animals were injected (i.p.) with GTA, increasing the total GTA dose resulted in decreased direct PFC responses to SRBC. Suppression was also observed when GTA-deprived rats were force-fed GTA-containing Bacillus sp. ATCC 29726. The phenomenon of suppression by dietary GTA was not restricted to responses to SRBC, as similar results were obtained with chicken erythrocytes. When IgG PFC were measured, no difference between conventional and GTA-deprived groups was observed. Thus, an IgM-IgG shift does not seem to play a role in the mechanism of suppression by GTA. PMID:7021168

  17. pH-Responsive Fe(III)-Gallic Acid Nanoparticles for In Vivo Photoacoustic-Imaging-Guided Photothermal Therapy.

    PubMed

    Zeng, Jianfeng; Cheng, Ming; Wang, Yong; Wen, Ling; Chen, Ling; Li, Zhen; Wu, Yongyou; Gao, Mingyuan; Chai, Zhifang

    2016-04-01

    pH-responsive biocompatible Fe(III)-gallic acid nanoparticles with strong near-infrared absorbance are very stable in mild acidic conditions, but easily decomposed in neutral conditions, which enables the nanoparticles to be stable in a tumor and easily metabolized in other organs, thus providing a safe nanoplatform for in vivo photoacoustic imaging/photothermal therapy theranostic applications. PMID:26845393

  18. Effects of dietary humic and butyric acid on growth performance and response to lipopolysaccharide in young pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Humic acid (MFG) and fat protected butyric acid (BA) has been shown to modulate energy metabolism and inflammation. Therefore, the objectives of this study were to determine the effects of MFG and BA, alone and in combination, on growth performance and response to lipopolysaccharide (LPS) induced in...

  19. Milk production responses to dietary stearic acid vary by production level in dairy cattle.

    PubMed

    Piantoni, P; Lock, A L; Allen, M S

    2015-03-01

    Effects of stearic acid supplementation on feed intake and metabolic and production responses of dairy cows with a wide range of milk production (32.2 to 64.4 kg/d) were evaluated in a crossover design experiment with a covariate period. Thirty-two multiparous Holstein cows (142±55 d in milk) were assigned randomly within level of milk yield to treatment sequence. Treatments were diets supplemented (2% of diet dry matter) with stearic acid (SA; 98% C18:0) or control (soyhulls). The diets were based on corn silage and alfalfa and contained 24.5% forage neutral detergent fiber, 25.1% starch, and 17.3% crude protein. Treatment periods were 21 d with the final 4 d used for data and sample collection. Compared with the control, SA increased dry matter intake (DMI; 26.1 vs. 25.2 kg/d) and milk yield (40.2 vs. 38.5 kg/d). Stearic acid had no effect on the concentration of milk components but increased yields of fat (1.42 vs. 1.35 kg/d), protein (1.19 vs. 1.14 kg/d), and lactose (1.96 vs. 1.87 kg/d). The SA treatment increased 3.5% fat-corrected milk (3.5% FCM; 40.5 vs. 38.6 kg/d) but did not affect feed efficiency (3.5% FCM/DMI, 1.55 vs. 1.53), body weight, or body condition score compared with the control. Linear interactions between treatment and level of milk yield during the covariate period were detected for DMI and yields of milk, fat, protein, lactose, and 3.5% FCM; responses to SA were positively related to milk yield of cows. The SA treatment increased crude protein digestibility (67.4 vs. 65.5%), tended to increase neutral detergent fiber digestibility (43.6 vs. 42.3%), decreased fatty acid (FA) digestibility (56.6 vs. 76.1%), and did not affect organic matter digestibility. Fatty acid yield response, calculated as the additional FA yield secreted in milk per unit of additional FA intake, was only 13.3% for total FA and 8.2% for C18:0 plus cis-9 C18:1. Low estimated digestibility of the SA supplement was at least partly responsible for the low FA yield response

  20. Linking pattern recognition and salicylic acid responses in Arabidopsis through ACCELERATED CELL DEATH6 and receptors

    PubMed Central

    Tateda, Chika; Zhang, Zhongqin; Greenberg, Jean T

    2015-01-01

    The Arabidopsis membrane protein ACCELERATED CELL DEATH 6 (ACD6) and the defense signal salicylic acid (SA) are part of a positive feedback loop that regulates the levels of at least 2 pathogen-associated molecular patterns (PAMP) receptors, including FLAGELLIN SENSING 2 (FLS2) and CHITIN ELICITOR RECEPTOR (LYSM domain receptor-like kinase 1, CERK1). ACD6- and SA-mediated regulation of these receptors results in potentiation of responses to FLS2 and CERK1 ligands (e.g. flg22 and chitin, respectively). ACD6, FLS2 and CERK1 are also important for callose induction in response to an SA agonist even in the absence of PAMPs. Here, we report that another receptor, EF-Tu RECEPTOR (EFR) is also part of the ACD6/SA signaling network, similar to FLS2 and CERK1. PMID:26442718

  1. Behavioral and electrophysiological responses of Aedes albopictus to certain acids and alcohols present in human skin emanations.

    PubMed

    Guha, Lopamudra; Seenivasagan, T; Iqbal, S Thanvir; Agrawal, O P; Parashar, B D

    2014-10-01

    Human skin emanations attract hungry female mosquitoes toward their host for blood feeding. In this study, we report the flight orientation and electroantennogram response of Aedes albopictus females to certain unsaturated acids and alcohols found in human skin. In the Y-tube olfactometer, odors of lactic acid and 2-methyl-3-pentanol attracted 54-65% of Ae. albopictus females at all doses in a dose-dependent manner. However, at the highest dose (10(-2) g), the acids repelled 40-45% females. Attractancy (ca. 62-68%) at lower doses and repellency (ca. 30-45%) at higher doses were recorded for 3-methyl-3-pentanol and 1-octen-3-ol, while 5-hexen-1-ol, cis-2-hexen-1-ol, and trans 2-hexen-1-ol odor repelled ca. 55-65% of Ae. albopictus females at all doses. Antenna of female Ae. albopictus exhibited a dose-dependent EAG response up to 10(-3) g of L-lactic acid, trans-2-methyl-2-pentenoic acid, 2-octenoic acid, trans-2-hexen-1-ol and 1-octen-3-ol stimulations; however, the highest dose (10(-2) g) caused a little decline in the EAG response. EAG response of 9-10-fold was elicited by lactic acid, 2-octenoic acid, trans-2-hexenoic acid, and 3-methyl-3-pentanol, while cis-2-hexen-1-ol and trans-2-methyl pentenoic acid elicited 1-5-fold responses compared to solvent control. A blend of attractive compounds could be utilized in odor-baited trap for surveillance and repellent molecules with suitable formulation could be used to reduce the biting menace of mosquitoes. PMID:25049052

  2. Temperature and pH responsiveness of poly-(DMAA-co-unsaturated carboxylic acid) hydrogels synthesized by UV-irradiation

    NASA Astrophysics Data System (ADS)

    Kakinoki, Sachiro; Kaetsu, Isao; Nakayama, Masashi; Sutani, Kouichi; Uchida, Kumao; Yukutake, Kouji

    2003-07-01

    Stimuli-responsive polyampholyte hydrogels were synthesized by the copolymerization of dimethylaminoethyl methacrylate (DMAA) and acrylic acid (AAc) or itaconic acid (IAc) by UV-irradiation. Temperature and pH responsiveness of these hydrogels were studied. The temperature responsiveness of poly-(DMAA-co-AAc, IAc) hydrogels shown in change of water content became dull compared to that of DMAA homo-polymer hydrogel. The water content of the poly-(DMAA-co-AAc, IAc) hydrogels showed a minimum at pH 8, and increased in more acidic and alkaline regions. This fact can be attributed to the coexistence of anions and cations in the poly-(DMAA-co-AAc, IAc) hydrogels. The poly-(DMAA-co-AAc, IAc) hydrogels were polyampholyte having both temperature responsiveness and pH responsiveness.

  3. Effect of thyroxine supplementation on the response to perfluoro-n-decanoic acid (PFDA) in rats

    SciTech Connect

    Gutshall, D.M.; Pilcher, G.D.; Langley, A.E.

    1988-01-01

    Perfluoro-n-decanoic acid (PFDA) is a member of a family of perfluorinated carboxylic acids that have found widespread commercial applications as lubricants, surfactants, wetting agents and corrosion inhibitors. The effects of thyroxine (T{sub 4}) supplementation on perfluoro-n-decanoic acid- (PFDA) induced decreases in food consumption, body weight, and body temperature were examined. A dose-response study was carried out with 50-, 100-, 200-, or 250-{mu}g/kg ip doses of T{sub 4} for 7 d prior to PFDA administration, and daily dosing with T{sub 4} was continued for an additional 30 d. From this study a T{sub 4} dose of 200 {mu}g/kg was chosen, and subsequent experiments were conducted with this dose. Supplementation with T{sub 4} at 200 {mu}g/kg daily alleviated the hypophagia but not the severe weight loss and hypothermia produced by PFDA treatment. Their results suggest that some component of the thyroid axis plays a role in feeding behavior. In addition, the PFDA-induced wasting syndrome and hypothermia appear to be unrelated to changes in serum thyroid hormones. The unexpected observation that severe weight loss occurred in the presence of essentially normal food intake suggests that PFDA alters basic cellular metabolic processes.

  4. Growth response of Pinus ponderosa seedlings and mature tree branches to acid rain and ozone exposure

    SciTech Connect

    Anderson, P.D.; Houpis, J.L.J.; Helms, J.A.

    1994-10-01

    Forests of the central and southern Sierra Nevada in California have been subjected to chronic damage by ozone and other atmospheric pollutants for the past several decades. Until recently, pollutant exposure of northern Sierra Nevada forests has been mild but increasing population and changes in land use throughout the Sacramento Valley and Sierra Nevada foothills may lead to increased pollutant damage in these forests. Although, better documented in other regions of the United States, little is known regarding the potential for acidic precipitation damage to Sierra Nevada forests. Only recently have studies directed towards understanding the potential interactive effects of ozone and acidic precipitation been undertaken. A key issue in resolving potential regional impacts of pollutants on forests is the extent to which research results can be scaled across genotypes and life-stages. Most of the pollution research to date has been performed using seedlings with varying degrees of genetic control. It is important to determine if the results obtained in such studies can be extrapolated to mature trees and to different genetic sources. In this paper, we present results from a one-year study examining the interactive effects of foliar exposure to acidic rain and ozone on the growth of ponderosa pine (Pinus ponderosa), a conifer known to be sensitive to ozone. The response to pollutants is characterized for both seedlings and mature tree branches of three genotypes grown in a common environment.

  5. Breast Cancer Genetic and Molecular Subtype Impacts Response to Omega-3 Fatty Acid Ethyl Esters.

    PubMed

    Chen, Ching Hui; Fabian, Carol; Hursting, Stephen; deGraffenried, Linda A

    2016-01-01

    Epidemiological studies have correlated frequent omega-3 (n-3) fatty acid consumption with a lower risk for breast cancer; however, recent prospective studies have been less conclusive. Efforts in the preventive setting have focused on the use of n-3 fatty acids, and the pharmaceutical ethyl esters (EE) of these natural compounds, for high-risk patient populations. Limited understanding of specific mechanisms by which these agents function has hampered identification of the cancer subtype(s) that would gain the greatest therapeutic benefit. In this study, we investigated the in vitro effects of n-3 EEs in four distinct breast cancer subtypes and explored how they affect not only breast cancer cell survival but also modulate the nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB) and peroxisome proliferator-activated receptor gamma signaling pathways. Similar to the high variance in response observed in human studies, we found that the effectiveness of n-3 EEs depends on the molecular characteristics of the MCF-7, CAMA-1, MDA-MB-231, and SKBR3 breast cancer cell lines and is closely associated with the suppression of NF-κB. These data strongly suggest that the use of n-3 fatty acids and their pharmaceutical ether esters in the prevention and therapeutic setting should be guided by specific tumor characteristics. PMID:27367296

  6. RAGE is a nucleic acid receptor that promotes inflammatory responses to DNA

    PubMed Central

    Sirois, Cherilyn M.; Jin, Tengchuan; Miller, Allison L.; Bertheloot, Damien; Nakamura, Hirotaka; Horvath, Gabor L.; Mian, Abubakar; Jiang, Jiansheng; Schrum, Jacob; Bossaller, Lukas; Pelka, Karin; Garbi, Natalio; Brewah, Yambasu; Tian, Jane; Chang, ChewShun; Chowdhury, Partha S.; Sims, Gary P.; Kolbeck, Roland; Coyle, Anthony J.; Humbles, Alison A.

    2013-01-01

    Recognition of DNA and RNA molecules derived from pathogens or self-antigen is one way the mammalian immune system senses infection and tissue damage. Activation of immune signaling receptors by nucleic acids is controlled by limiting the access of DNA and RNA to intracellular receptors, but the mechanisms by which endosome-resident receptors encounter nucleic acids from the extracellular space are largely undefined. In this study, we show that the receptor for advanced glycation end-products (RAGE) promoted DNA uptake into endosomes and lowered the immune recognition threshold for the activation of Toll-like receptor 9, the principal DNA-recognizing transmembrane signaling receptor. Structural analysis of RAGE–DNA complexes indicated that DNA interacted with dimers of the outermost RAGE extracellular domains, and could induce formation of higher-order receptor complexes. Furthermore, mice deficient in RAGE were unable to mount a typical inflammatory response to DNA in the lung, indicating that RAGE is important for the detection of nucleic acids in vivo. PMID:24081950

  7. Unravelling the Structural and Molecular Basis Responsible for the Anti-Biofilm Activity of Zosteric Acid

    PubMed Central

    Cattò, Cristina; Dell’Orto, Silvia; Villa, Federica; Villa, Stefania; Gelain, Arianna; Vitali, Alberto; Marzano, Valeria; Baroni, Sara; Forlani, Fabio; Cappitelli, Francesca

    2015-01-01

    The natural compound zosteric acid, or p-(sulfoxy)cinnamic acid (ZA), is proposed as an alternative biocide-free agent suitable for preventive or integrative anti-biofilm approaches. Despite its potential, the lack of information concerning the structural and molecular mechanism of action involved in its anti-biofilm activity has limited efforts to generate more potent anti-biofilm strategies. In this study a 43-member library of small molecules based on ZA scaffold diversity was designed and screened against Escherichia coli to understand the structural requirements necessary for biofilm inhibition at sub-lethal concentrations. Considerations concerning the relationship between structure and anti-biofilm activity revealed that i) the para-sulfoxy ester group is not needed to exploit the anti-biofilm activity of the molecule, it is the cinnamic acid scaffold that is responsible for anti-biofilm performance; ii) the anti-biofilm activity of ZA derivatives depends on the presence of a carboxylate anion and, consequently, on its hydrogen-donating ability; iii) the conjugated aromatic system is instrumental to the anti-biofilm activities of ZA and its analogues. Using a protein pull-down approach, combined with mass spectrometry, the herein-defined active structure of ZA was matrix-immobilized, and was proved to interact with the E. coli NADH:quinone reductase, WrbA, suggesting a possible role of this protein in the biofilm formation process. PMID:26132116

  8. pH-Responsive Behavior of Poly(acrylic acid) Brushes of Varying Thickness

    NASA Astrophysics Data System (ADS)

    Yadav, Vivek; Robertson, Megan; Conrad, Jacinta

    2015-03-01

    We have investigated the pH-dependent response of polyelectrolyte brushes of varying thickness. Our model system consists of poly(acrylic acid) brushes, which change from hydrophobic and neutral at low pH to hydrophilic and negatively charged at high pH, synthesized using a grafting-from approach at constant grafting density. As the polymer brush thickness increased, the brushes exhibited greater hysteresis in static water contact angle as a function of pH. We extracted the pKa of the polymer brushes from contact angle measurements. The relationship between the pKa and brush thickness depended on the order in which the brushes were exposed to solutions of varying pH: pKa decreased on increasing brush thickness when going from basic to acidic medium whereas pKa increased on increasing brush thickness when going from acidic to basic medium. We speculate that the origin of hysteresis can be explained by pH-dependent conformational changes in these polyelectrolyte brushes.

  9. Murine GPRC6A Mediates Cellular Responses to L-Amino Acids, but Not Osteocalcin Variants

    PubMed Central

    Rueda, Patricia; Harley, Elizabeth; Lu, Yao; Stewart, Gregory D.; Fabb, Stewart; Diepenhorst, Natalie; Cremers, Béatrice; Rouillon, Marie-Hélène; Wehrle, Isabelle; Geant, Anne; Lamarche, Gwladys; Leach, Katie; Charman, William N.; Christopoulos, Arthur; Summers, Roger J.; Sexton, Patrick M.; Langmead, Christopher J.

    2016-01-01

    Phenotyping of Gprc6a KO mice has shown that this promiscuous class C G protein coupled receptor is variously involved in regulation of metabolism, inflammation and endocrine function. Such effects are described as mediated by extracellular calcium, L-amino acids, the bone-derived peptide osteocalcin (OCN) and the male hormone testosterone, introducing the concept of a bone-energy-metabolism-reproduction functional crosstalk mediated by GPRC6A. However, whilst the calcium and L-amino acid-sensing properties of GPRC6A are well established, verification of activity of osteocalcin at both human and mouse GPRC6A in vitro has proven somewhat elusive. This study characterises the in vitro pharmacology of mouse GPRC6A in response to its putative ligands in both recombinant and endogenous GPRC6A-expressing cells. Using cell signalling, and glucagon-like peptide (GLP)-1 and insulin release assays, our results confirm that basic L-amino acids act as agonists of the murine GPRC6A receptor in both recombinant cells and immortalised entero-endocrine and pancreatic β-cells. In contrast, our studies do not support a role for OCN as a direct ligand for mouse GPRC6A, suggesting that the reported in vivo effects of OCN that require GPRC6A may be indirect, rather than via direct activation of the receptor. PMID:26785252

  10. Optimization of clavulanic acid production by Streptomyces daufpe 3060 by response surface methodology.

    PubMed

    Marques, Daniela A Viana; Cunha, Márcia N Carneiro; Araújo, Janete M; Lima-Filho, José L; Converti, Attilio; Pessoa-Jr, Adalberto; Porto, Ana L Figueiredo

    2011-04-01

    Clavulanic acid is a ß-lactam antibiotic which has a potent ß-lactamase inhibiting activity. In order to optimize its production by the new isolate Streptomyces DAUFPE 3060, the influence of two independent variables, temperature and soybean flour concentration, on clavulanic acid and biomass concentrations was investigated in 250 mL-Erlenmeyers according to a 2(2) central composite design. To this purpose, temperature and soybean flour (SF) concentration were varied in the ranges 26-34°C and 10-50 g/L, respectively, and the results evaluated utilizing the Response Surface Methodology. The experimental maximum production of clavulanic acid (629 mg/L) was obtained at 32°C and 40 g/L SF after 48 h, while the maximum biomass concentration (3.9 g/L) at 30°C and 50 g/L soybean flour, respectively. These values are satisfactorily close to those (640 mg/L and 3.75 g/L, respectively) predicted by the model, thereby demonstrating the validity of the mathematical approach adopted in this study. PMID:24031677

  11. Optimization of clavulanic acid production by Streptomyces daufpe 3060 by response surface methodology

    PubMed Central

    Marques, Daniela A. Viana; Cunha, Márcia N. Carneiro; Araújo, Janete M.; Lima-Filho, José L.; Converti, Attilio; Pessoa-Jr, Adalberto; Porto, Ana L. Figueiredo

    2011-01-01

    Clavulanic acid is a ß-lactam antibiotic which has a potent ß-lactamase inhibiting activity. In order to optimize its production by the new isolate Streptomyces DAUFPE 3060, the influence of two independent variables, temperature and soybean flour concentration, on clavulanic acid and biomass concentrations was investigated in 250 mL-Erlenmeyers according to a 22 central composite design. To this purpose, temperature and soybean flour (SF) concentration were varied in the ranges 26–34°C and 10–50 g/L, respectively, and the results evaluated utilizing the Response Surface Methodology. The experimental maximum production of clavulanic acid (629 mg/L) was obtained at 32°C and 40 g/L SF after 48 h, while the maximum biomass concentration (3.9 g/L) at 30°C and 50 g/L soybean flour, respectively. These values are satisfactorily close to those (640 mg/L and 3.75 g/L, respectively) predicted by the model, thereby demonstrating the validity of the mathematical approach adopted in this study. PMID:24031677

  12. Electrical resistance response of polyaniline films to water, ethanol, and nitric acid solution

    NASA Astrophysics Data System (ADS)

    Yin, Hong-Xing; Li, Meng-Meng; Yang, H.; Long, Yun-Ze; Sun, Xin

    2010-08-01

    This paper reports on electrical resistance vs. aging time for the response of polyaniline films under exposure to water, ethanol and nitric acid (HNO3) solution. Camphor sulfonic acid-doped polyaniline films were prepared by a “doping-dedoping-redoping" method, the morphology and microstructures of the films were characterized by a scanning electron microscope and an x-ray diffractometer, the electrical resistance was measured by a four-probe method. It was found that a lower amount of water molecules infiltrating the film can decrease the film's resistance possibly due to an enhancement of charge carrier transfer between polyaniline chains, whereas excessive water molecules can swell inter-chain distances and result in a quick increase of resistance. The resistance of the film under exposure to ethanol increases and becomes much larger than the original value. However, HNO3 solution can decrease the film's resistance sharply possibly owing to doping effect of protonic acid. These results can help to understand the conduction mechanism in polyaniline films, and also indicate that the films have potential application in chemical sensors.

  13. Spectrum of Membrane Morphological Responses to Antibacterial Fatty Acids and Related Surfactants.

    PubMed

    Yoon, Bo Kyeong; Jackman, Joshua A; Kim, Min Chul; Cho, Nam-Joon

    2015-09-22

    Medium-chain saturated fatty acids and related compounds (e.g., monoglycerides) represent one class of membrane-active surfactants with antimicrobial properties. Most related studies have been in vitro evaluations of bacterial growth inhibition, and there is limited knowledge about how the compounds in this class destabilize lipid bilayers, which are the purported target within the bacterial cell membrane. Herein, the interaction between three representative compounds in this class and a supported lipid bilayer platform was investigated using quartz crystal microbalance-dissipation and fluorescence microscopy in order to examine membrane destabilization. The three tested compounds were lauric acid, sodium dodecyl sulfate, and glycerol monolaurate. For each compound, we discovered striking differences in the resulting morphological changes of supported lipid bilayers. The experimental trends indicate that the compounds have membrane-disruptive behavior against supported lipid bilayers principally above the respective critical micelle concentration values. The growth inhibition properties of the compounds against standard and methicillin-resistant Staphylococcus aureus bacterial strains were also tested. Taken together, the findings in this work improve our knowledge about how saturated fatty acids and related compounds destabilize lipid bilayers, offering insight into the corresponding molecular mechanisms that lead to membrane morphological responses. PMID:26325618

  14. Transcriptional and antioxidative responses to endogenous polyunsaturated fatty acid accumulation in yeast.

    PubMed

    Andrisic, Luka; Collinson, Emma J; Tehlivets, Oksana; Perak, Eleonora; Zarkovic, Tomislav; Dawes, Ian W; Zarkovic, Neven; Cipak Gasparovic, Ana

    2015-01-01

    Pathophysiology of polyunsaturated fatty acids (PUFAs) is associated with aberrant lipid and oxygen metabolism. In particular, under oxidative stress, PUFAs are prone to autocatalytic degradation via peroxidation, leading to formation of reactive aldehydes with numerous potentially harmful effects. However, the pathological and compensatory mechanisms induced by lipid peroxidation are very complex and not sufficiently understood. In our study, we have used yeast capable of endogenous PUFA synthesis in order to understand the effects triggered by PUFA accumulation on cellular physiology of a eukaryotic organism. The mechanisms induced by PUFA accumulation in S. cerevisiae expressing Hevea brasiliensis Δ12-fatty acid desaturase include down-regulation of components of electron transport chain in mitochondria as well as up-regulation of pentose-phosphate pathway and fatty acid β-oxidation at the transcriptional level. Interestingly, while no changes were observed at the transcriptional level, activities of two important enzymatic antioxidants, catalase and glutathione-S-transferase, were altered in response to PUFA accumulation. Increased intracellular glutathione levels further suggest an endogenous oxidative stress and activation of antioxidative defense mechanisms under conditions of PUFA accumulation. Finally, our data suggest that PUFA in cell membrane causes metabolic changes which in turn lead to adaptation to endogenous oxidative stress. PMID:25280400

  15. Toxicogenomic response of Mycobacterium bovis BCG to peracetic acid and a comparative analysis of the M. bovis BCG response to three oxidative disinfectants.

    PubMed

    Nde, Chantal W; Toghrol, Freshteh; Jang, Hyeung-Jin; Bentley, William E

    2011-04-01

    Tuberculosis is a leading cause of death worldwide and infects thousands of Americans annually. Mycobacterium bovis causes tuberculosis in humans and several animal species. Peracetic acid is an approved tuberculocide in hospital and domestic environments. This study presents for the first time the transcriptomic changes in M. bovis BCG after treatment with 0.1 mM peracetic acid for 10 and 20 min. This study also presents for the first time a comparison among the transcriptomic responses of M. bovis BCG to three oxidative disinfectants: peracetic acid, sodium hypochlorite, and hydrogen peroxide after 10 min of treatment. Results indicate that arginine biosynthesis, virulence, and oxidative stress response genes were upregulated after both peracetic acid treatment times. Three DNA repair genes were downregulated after 10 and 20 min and cell wall component genes were upregulated after 20 min. The devR-devS signal transduction system was upregulated after 10 min, suggesting a role in the protection against peracetic acid treatment. Results also suggest that peracetic acid and sodium hypochlorite both induce the expression of the ctpF gene which is upregulated in hypoxic environments. Further, this study reveals that in M. bovis BCG, hydrogen peroxide and peracetic acid both induce the expression of katG involved in oxidative stress response and the mbtD and mbtI genes involved in iron regulation/virulence. PMID:21152916

  16. Generation of dose-response relationships to assess the effects of acidity in precipitation on growth and productivity of vegetation

    SciTech Connect

    Evans, L.S.

    1981-01-01

    Experiments were performed with several plant species in natural environments as well in a greenhouse and/or tissue culture facilities to establish dose-response functions of plant responses to simulated acidic rain in order to determine environmental risk assessments to ambient levels of acidic rain. Response functions of foliar injury, biomass of leaves and seed of soybean and pinto beans, root yields of radishes and garden beets, and reproduction of bracken fern are considered. The dose-response function of soybean seed yields with the hydrogen ion concentration of simulated acidic rainfalls was expressed by the equation y = 21.06-1.01 log x where y = seed yield in grams per plant and x = the hydrogen concentration if ..mu..eq l/sup -1/. The correlation coefficient of this relationship was -0.90. A similar dose-response function was generated for percent fertilization of ferns in a forest understory. When percent fertilization is plotted on logarithmic scale with hydrogen ion concentration of the simulated rain solution, the Y intercept is 51.18, slope -0.041 with a correlation coefficient of -0.98. Other dose-response functions were generated that assist in a general knowledge as to which plant species and which physiological processes are most impacted by acidic precipitation. Some responses did not produce convenient dose-response relationships. In such cases the responses may be altered by other environmental factors or there may be no differences among treatment means.

  17. Renal response to acid loading in the developing lamb fetus, intact in utero.

    PubMed

    Daniel, S S; Bowe, E T; Lallemand, R; Yeh, M N; James, L S

    1975-01-01

    Response of the fetal kidney to metabolic acidosis was studied in five fetal lambs, 115-125 days gestation, in order to evaluate the renal contribution to elimination of hydrogen ion during intra-uterine development. Experiments were conducted on healthy unanesthetized fetuses, intact in utero, with catheters implanted at hysterotomy into a fetal femoral artery and vein and into the bladder via the urachus, four or more days prior to the study. A metabolic acidosis was induced by infusion of isotonic lactic acid, 15 m mole/kg, intravenously over a period of 90 minutes. Serial arterial samples were taken and urine collected in fractions before, during and for three hours following the infusion, for measurements of pH, bicarbonate, lactate and electrolytes as well as urine output. During the infusion, urine pH fell from 6.65 to 6.25 and was 6.34 three hours later (Figs. 1 to 4, Tabs. III to IV). Lactic acid infusion caused a prompt increase in urine output from a mean rate of 0.12 to a maximum of 0.28 ml/kg/min at the end of the infusion, returning to control rates three hours later. Lactate excretion increased from 0.05 to a maximum of 4.6 mumole/kg/min at the end of infusion; titratable acid increased from 0.22 to a maximum of 4 muEq/kg/min; the rates of excretion of lactate and titratable acid were still higher than control at the end of three hours. Ammonia excretion increased from 0.21 to a maximum of 0.56 muEq/kg/min three hours after the end of infusion. The acid infusion caused a small but significant fall in excretion of bicarbonate. During the 90 minutes of infusion and over the following three hours, about 800 mumole lactate was excreted while net acid excretion over the same period was no more than half that amount. The diuresis was also accompanied by a net loss of sodium and chloride, the excretion of these ions increasing more than threefold following acid infusion; excretion of potassium decreased to one-third its rate prior to the infusion. During

  18. Contribution of the different omega-3 fatty acid desaturase genes to the cold response in soybean

    PubMed Central

    Andreu, Vanesa; Alfonso, Miguel

    2012-01-01

    This study analysed the contribution of each omega-3 desaturase to the cold response in soybean. Exposure to cold temperatures (5 °C) did not result in great modifications of the linolenic acid content in leaf membrane lipids. However, an increase in the GmFAD3A transcripts was observed both in plant leaves and soybean cells whereas no changes in GmFAD3B or GmFAD3C expression levels were detected. This increase was reversible and accompanied by the accumulation of an mRNA encoding a truncated form of GmFAD3A (GmFAD3A-T), which originated from alternative splicing of GmFAD3A in response to cold. When the expression of plastidial omega-3 desaturases was analysed, a transient accumulation of GmFAD7-2 mRNA was detected upon cold exposure in mature soybean trifoliate leaves while GmFAD7-1 transcripts remained unchanged. No modification of the GmFAD8-1 and GmFAD8-2 transcripts was observed. The functionality of GmFAD3A, GmFAD3B, GmFAD3C and GmFAD3A-T was examined by heterologous expression in yeast. No activity was detected with GmFAD3A-T, consistent with the absence of one of the His boxes necessary for desaturase activity. The linolenic acid content of Sacharomyces cerevisiae cells overexpressing GmFAD3A or GmFAD3B was higher when the cultures were incubated at cooler temperatures, suggesting that reticular desaturases of the GmFAD3 family, and more specifically GmFAD3A, may play a role in the cold response, even in leaves. The data point to a regulatory mechanism of omega-3 fatty acid desaturases in soybean affecting specific isoforms in both the plastid and the endoplasmic reticulum to maintain appropriate levels of linolenic acid under low temperature conditions. PMID:22865909

  19. Determining Multiple Responses of Pseudomonas aeruginosa PAO1 to an Antimicrobial Agent, Free Nitrous Acid.

    PubMed

    Gao, Shu-Hong; Fan, Lu; Peng, Lai; Guo, Jianhua; Agulló-Barceló, Míriam; Yuan, Zhiguo; Bond, Philip L

    2016-05-17

    Free nitrous acid (FNA) has recently been demonstrated as an antimicrobial agent on a range of micro-organisms, especially in wastewater-treatment systems. However, the antimicrobial mechanism of FNA is largely unknown. Here, we report that the antimicrobial effects of FNA are multitargeted. The response of a model denitrifier, Pseudomnas aeruginosa PAO1 (PAO1), common in wastewater treatment, was investigated in the absence and presence of inhibitory level of FNA (0.1 mg N/L) under anaerobic denitrifying conditions. This was achieved through coupling gene expression analysis, by RNA sequencing, and with a suite of physiological analyses. Various transcripts exhibited significant changes in abundance in the presence of FNA. Respiration was likely inhibited because denitrification activity was severely depleted, and decreased transcript levels of most denitrification genes occurred. As a consequence, the tricarboxylic acid (TCA) cycle was inhibited due to the lowered cellular redox state in the FNA-exposed cultures. Meanwhile, during FNA exposure, PAO1 rerouted its carbon metabolic pathway from the TCA cycle to pyruvate fermentation with acetate as the end product as a possible survival mechanism. Additionally, protein synthesis was significantly decreased, and ribosome preservation was evident. These findings improve our understanding of PAO1 in response to FNA and contribute toward the potential application for use of FNA as an antimicrobial agent. PMID:27116299

  20. Angiotensin II modulates respiratory and acid-base responses to prolonged hypoxia in conscious dogs.

    PubMed

    Heitman, S J; Jennings, D B

    1998-08-01

    We tested the hypothesis that angiotensin II (ANG II) contributes to ventilatory and acid-base adaptations during 3-4 h of hypoxia (partial pressure of O2 in arterial blood approximately 43 Torr) in the conscious dog. Three protocols were carried out over 3-4 h in five dogs: 1) air control, 2) 12% O2 breathing, and 3) 12% O2 breathing with ANG II receptors blocked by infusion of saralasin (0. 5 microg . kg-1 . min-1). After 2 h of hypoxia, expired ventilation and alveolar ventilation progressively increased, and the partial pressure of CO2 in arterial blood and the difference between the arterial concentrations of strong cations and strong anions ([SID]) decreased. When the hypoxic chemoreceptor drive to breathe was abolished transiently for 30 s with 100% O2, the resultant central apneic time decreased between 0.5 and 2.5 h of hypoxia. All these adaptive responses to hypoxia were abolished by ANG II receptor block. Because plasma ANG II levels were lower during hypoxia and hypoxic release of arginine vasopressin from the pituitary into the plasma was prevented by ANG II receptor block, the brain renin-angiotensin system was likely involved. It is possible that ANG II mediates ventilatory and acid-base adaptive responses to prolonged hypoxia via alterations in ion transport to decrease [SID] in brain extracellular fluid rather than acting by a direct neural mechanism. PMID:9688673

  1. Plastid Located WHIRLY1 Enhances the Responsiveness of Arabidopsis Seedlings Toward Abscisic Acid

    PubMed Central

    Isemer, Rena; Krause, Kirsten; Grabe, Nils; Kitahata, Nobutaka; Asami, Tadao; Krupinska, Karin

    2012-01-01

    WHIRLY1 is a protein that can be translocated from the plastids to the nucleus, making it an ideal candidate for communicating information between these two compartments. Mutants of Arabidopsis thaliana lacking WHIRLY1 (why1) were shown to have a reduced sensitivity toward salicylic acid (SA) and abscisic acid (ABA) during germination. Germination assays in the presence of abamine, an inhibitor of ABA biosynthesis, revealed that the effect of SA on germination was in fact caused by a concomitant stimulation of ABA biosynthesis. In order to distinguish whether the plastid or the nuclear isoform of WHIRLY1 is adjusting the responsiveness toward ABA, sequences encoding either the complete WHIRLY1 protein or a truncated form lacking the plastid transit peptide were overexpressed in the why1 mutant background. In plants overexpressing the full-length sequence, WHIRLY1 accumulated in both plastids and the nucleus, whereas in plants overexpressing the truncated sequence, WHIRLY1 accumulated exclusively in the nucleus. Seedlings containing recombinant WHIRLY1 in both compartments were hypersensitive toward ABA. In contrast, seedlings possessing only the nuclear form of WHIRLY1 were as insensitive toward ABA as the why1 mutants. ABA was furthermore shown to lower the rate of germination of wildtype seeds even in the presence of abamine which is known to inhibit the formation of xanthoxin, the plastid located precursor of ABA. From this we conclude that plastid located WHIRLY1 enhances the responsiveness of seeds toward ABA even when ABA is supplied exogenously. PMID:23269926

  2. Regulation of water, salinity, and cold stress responses by salicylic acid

    PubMed Central

    Miura, Kenji; Tada, Yasuomi

    2014-01-01

    Salicylic acid (SA) is a naturally occurring phenolic compound. SA plays an important role in the regulation of plant growth, development, ripening, and defense responses. The role of SA in the plant–pathogen relationship has been extensively investigated. In addition to defense responses, SA plays an important role in the response to abiotic stresses, including drought, low temperature, and salinity stresses. It has been suggested that SA has great agronomic potential to improve the stress tolerance of agriculturally important crops. However, the utility of SA is dependent on the concentration of the applied SA, the mode of application, and the state of the plants (e.g., developmental stage and acclimation). Generally, low concentrations of applied SA alleviate the sensitivity to abiotic stresses, and high concentrations of applied induce high levels of oxidative stress, leading to a decreased tolerance to abiotic stresses. In this article, the effects of SA on the water stress responses and regulation of stomatal closure are reviewed. PMID:24478784

  3. Glossopharyngeal taste responses of the channel catfish to binary mixtures of amino acids.

    PubMed

    Ogawa, K; Caprio, J

    2000-10-01

    This study examines the neural processing of binary mixtures in the glossopharyngeal (IX) taste system of the channel catfish, Ictalurus punctatus, and finds that the nature of the components of a mixture determines the intensity of the neural response to it. Taste buds in fish innervated by IX are located along the gill rakers of the first gill arch and rostral floor of the oral cavity, and function primarily in the consummatory phase of feeding behavior; however, few studies of IX taste responses have been reported in any species of teleost. Here, we report IX taste responses to eight different binary mixtures of amino acids whose components were adjusted to be approximately equipotent in electrophysiological recordings. Four binary (group I) mixtures whose components were indicated from prior electrophysiological cross-adaptation experiments to bind to independent receptor sites resulted in significantly larger (22% average increase) integrated IX taste activity than four other (group II) binary mixtures whose components were indicated to bind to the same or highly cross-reactive receptor sites. These results are similar to those observed previously from facial nerve recordings in channel catfish, and to olfactory and taste responses in other vertebrate and invertebrate species. The group I results help to explain behavioral observations that chemical mixtures of chemosensory stimuli are often more stimulatory than their individual components. PMID:11015321

  4. Redirection of Epithelial Immune Responses by Short-Chain Fatty Acids through Inhibition of Histone Deacetylases.

    PubMed

    Lin, May Young; de Zoete, Marcel R; van Putten, Jos P M; Strijbis, Karin

    2015-01-01

    Short-chain fatty acids (SCFAs) are products of microbial fermentation that are important for intestinal epithelial health. Here, we describe that SCFAs have rapid and reversible effects on toll-like receptor (TLR) responses in epithelial cells. Incubation of HEK293 or HeLa epithelial cells with the SCFAs butyrate or propionate at physiological concentrations enhanced NF-κB activation induced by TLR5, TLR2/1, TLR4, and TLR9 agonists. NF-κB activation in response to tumor necrosis factor α (TNFα) was also increased by SCFAs. Comparative transcript analysis of HT-29 colon epithelial cells revealed that SCFAs enhanced TLR5-induced transcription of TNFα but dampened or even abolished the TLR5-mediated induction of IL-8 and monocyte chemotactic protein 1. SCFAs are known inhibitors of histone deacetylases (HDACs). Butyrate or propionate caused a rapid increase in histone acetylation in epithelial cells, similar to the small molecule HDAC inhibitor trichostatin A (TSA). TSA also mimicked the effects of SCFAs on TLR-NF-κB responses. This study shows that bacterial SCFAs rapidly alter the epigenetic state of host cells resulting in redirection of the innate immune response and selective reprograming of cytokine/chemokine expression. PMID:26579129

  5. Brainstem amino acid neurotransmitters and ventilatory response to hypoxia in piglets.

    PubMed

    Hehre, Dorothy A; Devia, Carlos J; Bancalari, Eduardo; Suguihara, Cleide

    2008-01-01

    The ventilatory response to hypoxia is influenced by the balance between inhibitory (GABA, glycine, and taurine) and excitatory (glutamate and aspartate) brainstem amino acid (AA) neurotransmitters. To assess the effects of AA in the nucleus tractus solitarius (NTS) on the ventilatory response to hypoxia at 1 and 2 wk of age, inhibitory and excitatory AA were sampled by microdialysis in unanesthetized and chronically instrumented piglets. Microdialysis samples from the NTS area were collected at 5-min intervals and minute ventilation (VE), arterial blood pressure (ABP), and arterial blood gases (ABG) were measured while the animals were in quiet sleep. A biphasic ventilatory response to hypoxia was observed in wk 1 and 2, but the decrease in VE at 10 and 15 min was more marked in wk 1. This was associated with an increase in inhibitory AA during hypoxia in wk 1. Excitatory AA levels were elevated during hypoxia in wk 1 and 2. Changes in ABP, pH, and ABG during hypoxia were not different between weeks. These data suggest that the larger depression in the ventilatory response to hypoxia observed in younger piglets is mediated by predominance of the inhibitory AA neurotransmitters, GABA, glycine, and taurine, in the NTS. PMID:18043517

  6. A Nuclear Factor Regulates Abscisic Acid Responses in Arabidopsis1[W][OA

    PubMed Central

    Kim, Min Jung; Shin, Ryoung; Schachtman, Daniel P.

    2009-01-01

    Abscisic acid (ABA) is a plant hormone that regulates plant growth as well as stress responses. In this study, we identified and characterized a new Arabidopsis (Arabidopsis thaliana) protein, Nuclear Protein X1 (NPX1), which was up-regulated by stress and treatment with exogenous ABA. Stomatal closure, seed germination, and primary root growth are well-known ABA responses that were less sensitive to ABA in NPX1-overexpressing plants. NPX1-overexpressing plants were more drought sensitive, and the changes in response to drought were due to the altered guard cell sensitivity to ABA in transgenic plants and not to a lack of ABA production. The nuclear localization of NPX1 correlated with changes in the expression of genes involved in ABA biosynthesis and ABA signal transduction. To understand the function of NPX1, we searched for interacting proteins and found that an ABA-inducible NAC transcription factor, TIP, interacted with NPX1. Based on the whole plant phenotypes, we hypothesized that NPX1 acts as a transcriptional repressor, and this was demonstrated in yeast, where we showed that TIP was repressed by NPX1. Our results indicate that the previously unknown protein NPX1 acts as a negative regulator in plant response to changes in environmental conditions through the control of ABA-regulated gene expression. The characterization of this factor enhances our understanding of guard cell function and the mechanisms that plants use to modulate water loss from leaves under drought conditions. PMID:19759343

  7. Glucose-responsive insulin activity by covalent modification with aliphatic phenylboronic acid conjugates.

    PubMed

    Chou, Danny Hung-Chieh; Webber, Matthew J; Tang, Benjamin C; Lin, Amy B; Thapa, Lavanya S; Deng, David; Truong, Jonathan V; Cortinas, Abel B; Langer, Robert; Anderson, Daniel G

    2015-02-24

    Since its discovery and isolation, exogenous insulin has dramatically changed the outlook for patients with diabetes. However, even when patients strictly follow an insulin regimen, serious complications can result as patients experience both hyperglycemic and hypoglycemic states. Several chemically or genetically modified insulins have been developed that tune the pharmacokinetics of insulin activity for personalized therapy. Here, we demonstrate a strategy for the chemical modification of insulin intended to promote both long-lasting and glucose-responsive activity through the incorporation of an aliphatic domain to facilitate hydrophobic interactions, as well as a phenylboronic acid for glucose sensing. These synthetic insulin derivatives enable rapid reversal of blood glucose in a diabetic mouse model following glucose challenge, with some derivatives responding to repeated glucose challenges over a 13-h period. The best-performing insulin derivative provides glucose control that is superior to native insulin, with responsiveness to glucose challenge improved over a clinically used long-acting insulin derivative. Moreover, continuous glucose monitoring reveals responsiveness matching that of a healthy pancreas. This synthetic approach to insulin modification could afford both long-term and glucose-mediated insulin activity, thereby reducing the number of administrations and improving the fidelity of glycemic control for insulin therapy. The described work is to our knowledge the first demonstration of a glucose-binding modified insulin molecule with glucose-responsive activity verified in vivo. PMID:25675515

  8. Glucose-responsive insulin activity by covalent modification with aliphatic phenylboronic acid conjugates

    PubMed Central

    Chou, Danny Hung-Chieh; Webber, Matthew J.; Tang, Benjamin C.; Lin, Amy B.; Thapa, Lavanya S.; Deng, David; Truong, Jonathan V.; Cortinas, Abel B.; Langer, Robert; Anderson, Daniel G.

    2015-01-01

    Since its discovery and isolation, exogenous insulin has dramatically changed the outlook for patients with diabetes. However, even when patients strictly follow an insulin regimen, serious complications can result as patients experience both hyperglycemic and hypoglycemic states. Several chemically or genetically modified insulins have been developed that tune the pharmacokinetics of insulin activity for personalized therapy. Here, we demonstrate a strategy for the chemical modification of insulin intended to promote both long-lasting and glucose-responsive activity through the incorporation of an aliphatic domain to facilitate hydrophobic interactions, as well as a phenylboronic acid for glucose sensing. These synthetic insulin derivatives enable rapid reversal of blood glucose in a diabetic mouse model following glucose challenge, with some derivatives responding to repeated glucose challenges over a 13-h period. The best-performing insulin derivative provides glucose control that is superior to native insulin, with responsiveness to glucose challenge improved over a clinically used long-acting insulin derivative. Moreover, continuous glucose monitoring reveals responsiveness matching that of a healthy pancreas. This synthetic approach to insulin modification could afford both long-term and glucose-mediated insulin activity, thereby reducing the number of administrations and improving the fidelity of glycemic control for insulin therapy. The described work is to our knowledge the first demonstration of a glucose-binding modified insulin molecule with glucose-responsive activity verified in vivo. PMID:25675515

  9. ABC transporter AtABCG25 is involved in abscisic acid transport and responses

    PubMed Central

    Kuromori, Takashi; Miyaji, Takaaki; Yabuuchi, Hikaru; Shimizu, Hidetada; Sugimoto, Eriko; Kamiya, Asako; Moriyama, Yoshinori; Shinozaki, Kazuo

    2010-01-01

    Abscisic acid (ABA) is one of the most important phytohormones involved in abiotic stress responses, seed maturation, germination, and senescence. ABA is predominantly produced in vascular tissues and exerts hormonal responses in various cells, including guard cells. Although ABA responses require extrusion of ABA from ABA-producing cells in an intercellular ABA signaling pathway, the transport mechanisms of ABA through the plasma membrane remain unknown. Here we isolated an ATP-binding cassette (ABC) transporter gene, AtABCG25, from Arabidopsis by genetically screening for ABA sensitivity. AtABCG25 was expressed mainly in vascular tissues. The fluorescent protein-fused AtABCG25 was localized at the plasma membrane in plant cells. In membrane vesicles derived from AtABCG25-expressing insect cells, AtABCG25 exhibited ATP-dependent ABA transport. The AtABCG25-overexpressing plants showed higher leaf temperatures, implying an influence on stomatal regulation. These results strongly suggest that AtABCG25 is an exporter of ABA and is involved in the intercellular ABA signaling pathway. The presence of the ABA transport mechanism sheds light on the active control of multicellular ABA responses to environmental stresses among plant cells. PMID:20133881

  10. The Arabidopsis LYST INTERACTING PROTEIN 5 Acts in Regulating Abscisic Acid Signaling and Drought Response.

    PubMed

    Xia, Zongliang; Huo, Yongjin; Wei, Yangyang; Chen, Qiansi; Xu, Ziwei; Zhang, Wei

    2016-01-01

    Multivesicular bodies (MVBs) are unique endosomes containing vesicles in the lumens and play essential roles in many eukaryotic cellular processes. The Arabidopsis LYST INTERACTING PROTEIN 5 (LIP5), a positive regulator of MVB biogenesis, has critical roles in biotic and abiotic stress responses. However, whether the abscisic acid (ABA) signaling is involved in LIP5-mediated stress response is largely unknown. Here, we report that LIP5 functions in regulating ABA signaling and drought response in Arabidopsis. Analyses of a LIP5 promoter-β-glucuronidase (GUS) construct revealed substantial GUS activity in whole seedlings. The expression of LIP5 was induced by ABA and drought, and overexpression of LIP5 led to ABA hypersensitivity, enhanced stomatal closure, reduced water loss, and, therefore, increased drought tolerance. On the contrary, LIP5 knockdown mutants showed ABA-insensitive phenotypes and reduced drought tolerance; suggesting that LIP5 acts in regulating ABA response. Further analysis using a fluorescent dye revealed that ABA and water stress induced cell endocytosis or vesicle trafficking in a largely LIP5-dependent manner. Furthermore, expression of several drought- or ABA-inducible marker genes was significantly down-regulated in the lip5 mutant seedlings. Collectively, our data suggest that LIP5 positively regulates drought tolerance through ABA-mediated cell signaling. PMID:27313589

  11. Role of acid sphingomyelinase bioactivity in human CD4+ T-cell activation and immune responses

    PubMed Central

    Bai, A; Kokkotou, E; Zheng, Y; Robson, S C

    2015-01-01

    Acid sphingomyelinase (ASM), a lipid hydrolase enzyme, has the potential to modulate various cellular activation responses via the generation of ceramide and by interaction with cellular receptors. We have hypothesized that ASM modulates CD4+ T-cell receptor activation and impacts immune responses. We first observed interactions of ASM with the intracellular domains of both CD3 and CD28. ASM further mediates T-cell proliferation after anti-CD3/CD28 antibody stimulation and alters CD4+ T-cell activation signals by generating ceramide. We noted that various pharmacological inhibitors of ASM or knockdown of ASM using small hairpin RNA inhibit CD3/CD28-mediated CD4+ T-cell proliferation and activation. Furthermore, such blockade of ASM bioactivity by biochemical inhibitors and/or molecular-targeted knockdown of ASM broadly abrogate T-helper cell responses. In conclusion, we detail immune, pivotal roles of ASM in adaptive immune T-cell responses, and propose that these pathways might provide novel targets for the therapy of autoimmune and inflammatory diseases. PMID:26203857

  12. Taxifolin glycoside inhibits dendritic cell responses stimulated by lipopolysaccharide and lipoteichoic acid.

    PubMed

    Kim, Yun Jeong; Choi, Sun Eun; Lee, Min Won; Lee, Chung Soo

    2008-11-01

    Antigen-presenting dendritic cells may play an important role in the pathogenesis of atopic dermatitis. Taxifolin is demonstrated to have anti-inflammatory effects. The present study was designed to assess the effect of taxifolin glycoside against stimulated responses of dendritic cells isolated from mouse bone marrow and spleen. Dendritic cells exposed to lipopolysaccharide, lipoteichoic acid or interleukin (IL)-1beta exhibited increased production of IL-12 p70 and tumour necrosis factor alpha, increased formation of reactive oxygen species (ROS) and nitric oxide (NO), and elevation of intracellular Ca2+ levels. Treatment with taxifolin glycoside inhibited responses stimulated by the microbial products or IL-1beta in dendritic cells in a dose-dependent manner. Taxifolin glycoside had a significant inhibitory effect on the production of cytokines, formation of ROS and NO, and change in intracellular Ca2+ levels in dendritic cells of bone marrow and spleen. The results show that taxifolin glycoside seems to inhibit the dendritic cell responses stimulated by microbial products and IL-1beta, suggesting that taxifolin glycoside may exert an inhibitory effect against dendritic-cell-mediated immune responses. PMID:18957167

  13. The Arabidopsis LYST INTERACTING PROTEIN 5 Acts in Regulating Abscisic Acid Signaling and Drought Response

    PubMed Central

    Xia, Zongliang; Huo, Yongjin; Wei, Yangyang; Chen, Qiansi; Xu, Ziwei; Zhang, Wei

    2016-01-01

    Multivesicular bodies (MVBs) are unique endosomes containing vesicles in the lumens and play essential roles in many eukaryotic cellular processes. The Arabidopsis LYST INTERACTING PROTEIN 5 (LIP5), a positive regulator of MVB biogenesis, has critical roles in biotic and abiotic stress responses. However, whether the abscisic acid (ABA) signaling is involved in LIP5-mediated stress response is largely unknown. Here, we report that LIP5 functions in regulating ABA signaling and drought response in Arabidopsis. Analyses of a LIP5 promoter-β-glucuronidase (GUS) construct revealed substantial GUS activity in whole seedlings. The expression of LIP5 was induced by ABA and drought, and overexpression of LIP5 led to ABA hypersensitivity, enhanced stomatal closure, reduced water loss, and, therefore, increased drought tolerance. On the contrary, LIP5 knockdown mutants showed ABA-insensitive phenotypes and reduced drought tolerance; suggesting that LIP5 acts in regulating ABA response. Further analysis using a fluorescent dye revealed that ABA and water stress induced cell endocytosis or vesicle trafficking in a largely LIP5-dependent manner. Furthermore, expression of several drought- or ABA-inducible marker genes was significantly down-regulated in the lip5 mutant seedlings. Collectively, our data suggest that LIP5 positively regulates drought tolerance through ABA-mediated cell signaling. PMID:27313589

  14. Transcriptional and cellular responses of the green alga Chlamydomonas reinhardtii to perfluoroalkyl phosphonic acids.

    PubMed

    Sanchez, David; Houde, Magali; Douville, Mélanie; De Silva, Amila O; Spencer, Christine; Verreault, Jonathan

    2015-03-01

    Perfluoroalkyl phosphonic acids (PFPAs), a new class of perfluoroalkyl substances used primarily in the industrial sector as surfactants, were recently detected in surface water and wastewater treatment plant effluents. Toxicological effects of PFPAs have as yet not been investigated in aquatic organisms. The objective of the present study was to evaluate the effects of perfluorooctylphosphonic acid (C8-PFPA) and perfluorodecylphosphonic acid (C10-PFPA) exposure (31-250μg/L) on Chlamydomonas reinhardtii using genomic (qRT-PCR), biochemical (reactive oxygen species production (ROS) and lipid peroxidation), and physiological (cellular viability) indicators. After 72h of exposure, no differences were observed in cellular viability for any of the two perfluorochemicals. However, increase in ROS concentrations (36% and 25.6% at 125 and 250μg/L, respectively) and lipid peroxidation (35.5% and 35.7% at 125 and 250μg/L, respectively) was observed following exposure to C10-PFPA. C8-PFPA exposure did not impact ROS production and lipid peroxidation in algae. To get insights into the molecular response and modes of action of PFPA toxicity, qRT-PCR-based assays were performed to analyze the transcription of genes related to antioxidant responses including superoxide dismutase (SOD-1), glutathione peroxidase (GPX), catalase (CAT), glutathione S-transferase (GST), and ascorbate peroxidase (APX I). Genomic analyses revealed that the transcription of CAT and APX I was up-regulated for all the C10-PFPA concentrations. In addition, PFPAs were quantified in St. Lawrence River surface water samples and detected at concentrations ranging from 250 to 850pg/L for C8-PFPA and 380 to 650pg/L for C10-PFPA. This study supports the prevalence of PFPAs in the aquatic environment and suggests potential impacts of PFPA exposure on the antioxidant defensive system in C. reinhardtii. PMID:25621396

  15. Response of DOC in Acid-Sensitive Maine Lakes to Decreasing Sulfur Deposition (1993 - 2009)

    NASA Astrophysics Data System (ADS)

    Oelsner, G. P.; Sanclements, M.; McKnight, D. M.; Stoddard, J. L.

    2010-12-01

    In response to the Clean Air Act Amendments of 1990, sulfur deposition has decreased across the northeastern United States. As a result, sulfate concentrations in lakes and streams have also decreased and many surface waters have become less acidic. Over the same time period, there has been a concurrent increase in dissolved organic carbon (DOC) concentrations in many lakes and streams which has been difficult to interpret. To assess the biogeochemical processes driving increasing DOC concentrations we analyzed archived samples from 9 acid-sensitive lakes in Maine collected between 1993 and 2009 using UV-Vis and fluorescence spectroscopy. The fluorescence index (FI) was calculated for all samples. The FI represents the ratio of the emission intensity at 450 nm to 550 nm at an excitation wavelength of 370 nm and provides information regarding the source of dissolved organic matter (DOM). This index has a value of approximately 1.9 for microbially derived fluvic acids and a value of approximately 1.4 for terrestrially (higher-plant) derived fluvic acids. All four lakes with increasing DOC trends had concomitant decreases in the FI index. Two of five lakes with no significant DOC trend also demonstrated no trend in FI values over time, while three lakes revealed a decrease in FI values. To confirm that the FI measured in whole water was primarily reflective of fulvic acids (FA), XAD-resin was used to isolate FA from a subset of samples. Analysis of the FA indicates that the FI values for the humic substances are slightly higher, yet well correlated with whole water samples. This suggests that despite prolonged storage in plastic, the FI trends are meaningful. The FI trends suggest a terrestrial source for the increasing DOC and may be driven by increased DOM production from soils experiencing decreased acid loading. Decreases in sulfate deposition can increase soil pH and soil organic matter solubility, as well as decrease the ionic strength of the soil solution, and

  16. Reduction in Dietary Omega-6 Polyunsaturated Fatty Acids: Eicosapentaenoic Acid plus Docosahexaenoic Acid Ratio Minimizes Atherosclerotic Lesion Formation and Inflammatory Response in the LDL Receptor Null Mouse

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dietary very long chain omega-3 polyunsaturated fatty acids (PUFA) have been associated with reduced CVD risk. LDL receptor null mice (LDLr-/-) were used to assess different dietary ratios of omega-6 PUFA to eicosapentaenoic acid plus docosahexaenoic acid (omega-6:EPA+DHA) on atherogenesis and infl...

  17. Acanthoic acid inhibits LPS-induced inflammatory response by activating LXRα in human umbilical vein endothelial cells.

    PubMed

    Li, Yong; Zhang, Xiao-Shi; Yu, Jin-Long

    2016-03-01

    Acanthoic acid, a pimaradiene diterpene isolated from Acanthopanax koreanum, has been reported to have anti-inflammatory activities. However, the effect of acanthoic acid on vascular inflammation has not been investigated. The aim of this study was to investigate the anti-inflammatory effects of acanthoic acid on lipopolysaccharide (LPS)-induced inflammatory response in human umbilical vein endothelial cells (HUVECs). The production of cytokines TNF-α and IL-8 was detected by ELISA. The expression of VCAM-1, ICAM-1, E-selectin, NF-κB and LXRα were detected by Western blotting. Adhesion of monocytes to HUVECs was detected by monocytic cell adhesion assay. The results showed that acanthoic acid dose-dependently inhibited LPS-induced TNF-α and IL-8 production. Acanthoic acid also inhibited TNF-α-induced IL-8 and IL-6 production. LPS-induced endothelial cell adhesion molecules, VCAM-1 and ICAM-1 were also inhibited by acanthoic acid. Acanthoic acid inhibited LPS-induced NF-κB activation. Furthermore, acanthoic acid dose-dependently up-regulated the expression of LXRα. In addition, our results showed that the anti-inflammatory effect of acanthoic acid was attenuated by transfection with LXRα siRNA. In conclusion, the anti-inflammatory effect of acanthoic acid is due to its ability to activate LXRα. Acanthoic acid may be a therapeutic agent for inflammatory cardiovascular disease. PMID:26803523

  18. Identification and characterization of the retinoic acid response elements in the human RIG1 gene promoter

    SciTech Connect

    Jiang, S.-Y.; Wu, M.-S.; Chen, L.-M.; Hung, M.-W.; Lin, H.-E.; Chang, G.-G.; Chang, T.-C. . E-mail: tcchang@ndmctsgh.edu.tw

    2005-06-03

    The expression of retinoic acid-induced gene 1 (RIG1), a class II tumor suppressor gene, is induced in cells treated with retinoids. RIG1 has been shown to express ubiquitously and the increased expression of this gene appears to suppress cell proliferation. Recent studies also demonstrated that this gene may play an important role in cell differentiation and the progression of cancer. In spite of the remarkable regulatory role of this protein, the molecular mechanism of RIG1 expression induced by retinoids remains to be clarified. The present study was designed to study the molecular mechanism underlying the all-trans retinoic acid (atRA)-mediated induction of RIG1 gene expression. Polymerase chain reaction was used to generate a total of 10 luciferase constructs that contain various fragments of the RIG1 5'-genomic region. These constructs were then transfected into human gastric cancer SC-M1 and breast cancer T47D cells for transactivation analysis. atRA exhibited a significant induction in luciferase activity only through the -4910/-5509 fragment of the 5'-genomic region of RIG1 gene relative to the translation initiation site. Further analysis of this promoter fragment indicated that the primary atRA response region is located in between -5048 and -5403 of the RIG1 gene. Within this region, a direct repeat sequence with five nucleotide spacing, 5'-TGACCTctattTGCCCT-3' (DR5, -5243/-5259), and an inverted repeat sequence with six nucleotide spacing, 5'-AGGCCAtggtaaTGGCCT-3' (IR6, -5323/-5340), were identified. Deletion and mutation of the DR5, but not the IR6 element, abolished the atRA-mediated activity. Electrophoretic mobility shift assays with nuclear extract from atRA-treated cells indicated the binding of retinoic acid receptor (RAR) and retinoid X receptor (RXR) heterodimers specifically to this response element. In addition to the functional DR5, the region contains many other potential sequence elements that are required to maximize the at

  19. LACK OF EFFECT OF AGE AND ANTIOXIDANT DEPLETION ON RESPIRATORY RESPONSES TO CONCENTRATED AMBIENT PARTICULATES (CAPS) IN RATS

    EPA Science Inventory

    2003 AAR PM Meeting
    Particulate Matter: Atmospheric Sciences,
    Exposure and the Fourth Colloquium on PM and Human Health

    LACK OF EFFECT OF AGE AND ANTIOXIDANT DEPLETION ON RESPIRATORY RESPONSES TO CONCENTRATED AMBIENT PARTICULATES (CAPs) IN RATS. JA Dye, LC Walsh, C...

  20. Role of Acinus in Regulating Retinoic Acid-Responsive Gene Pre-mRNA Splicing

    PubMed Central

    Wang, Fang; Soprano, Kenneth J.; Soprano, Dianne Robert

    2014-01-01

    Acinus-S’ is a co-repressor for retinoic acid receptor (RAR)-dependent gene transcription and has been suggested to be involved in RNA processing. In this study the role of Acinus isoforms in regulating pre-mRNA splicing was explored using in vivo splicing assays. Both Acinus-L and Acinus-S’, with the activity of Acinus-L higher than that of Acinus-S’, increase the splicing of a retinoic acid (RA)-responsive minigene containing a weak 5′ splice site but not a RA-responsive minigene containing a strong 5′ splice site. RA treatment further enhances the splicing of the weak 5′ splice site by Acinus in a dose- and time-dependent manner, suggesting a RA-dependent activity in addition to a RA-independent activity of Acinus. The RA-independent effect of Acinus occurs to varying degrees using minigene constructs containing several different promoters while the RA-dependent splicing activity of Acinus is specific for transcripts derived from the minigene driven by a RA response element (RARE)-containing promoter. This suggests that the ligand-dependent splicing activity of Acinus is related to the RA-activated RAR bound to the RARE. The RRM domain is necessary for the RA-dependent splicing activity of Acinus and the RA-independent splicing activity of Acinus is repressed by RNPS1. Importantly, measurement of the splicing of endogenous human RARβ and Bcl-x in vivo demonstrates that Acinus stimulates the use of the weaker alternative 5′ splice site of these two genes in a RA-dependent manner for RARβ and a RA-independent manner for Bcl-x. Taken together, these studies demonstrate that Acinus functions in both RAR-dependent splicing and RAR-dependent transcription. PMID:25205379

  1. Response to Vitamin B12 and Folic Acid in Myalgic Encephalomyelitis and Fibromyalgia

    PubMed Central

    Regland, Björn; Forsmark, Sara; Halaouate, Lena; Matousek, Michael; Peilot, Birgitta; Zachrisson, Olof; Gottfries, Carl-Gerhard

    2015-01-01

    Background Patients with myalgic encephalomyelitis (ME, also called chronic fatigue syndrome) may respond most favorably to frequent vitamin B12 injections, in vital combination with oral folic acid. However, there is no established algorithm for individualized optimal dosages, and rate of improvement may differ considerably between responders. Objective To evaluate clinical data from patients with ME, with or without fibromyalgia, who had been on B12 injections at least once a week for six months and up to several years. Methods 38 patients were included in a cross-sectional survey. Based on a validated observer’s rating scale, they were divided into Good (n = 15) and Mild (n = 23) responders, and the two groups were compared from various clinical aspects. Results Good responders had used significantly more frequent injections (p<0.03) and higher doses of B12 (p<0.03) for a longer time (p<0.0005), higher daily amounts of oral folic acid (p<0.003) in good relation with the individual MTHFR genotype, more often thyroid hormones (p<0.02), and no strong analgesics at all, while 70% of Mild responders (p<0.0005) used analgesics such as opioids, duloxetine or pregabalin on a daily basis. In addition to ME, the higher number of patients with fibromyalgia among Mild responders was bordering on significance (p<0.09). Good responders rated themselves as “very much” or “much” improved, while Mild responders rated “much” or “minimally” improved. Conclusions Dose-response relationship and long-lasting effects of B12/folic acid support a true positive response in the studied group of patients with ME/fibromyalgia. It’s important to be alert on co-existing thyroid dysfunction, and we suspect a risk of counteracting interference between B12/folic acid and certain opioid analgesics and other drugs that have to be demethylated as part of their metabolism. These issues should be considered when controlled trials for ME and fibromyalgia are to be designed. PMID

  2. dl-2-Hydroxyisocaproic Acid Attenuates Inflammatory Responses in a Murine Candida albicans Biofilm Model

    PubMed Central

    Nieminen, M. T.; Hernandez, M.; Novak-Frazer, L.; Kuula, H.; Ramage, G.; Bowyer, P.; Warn, P.; Sorsa, T.

    2014-01-01

    Chronic biofilm infections are often accompanied by a chronic inflammatory response, leading to impaired healing and increased, irreversible damage to host tissues. Biofilm formation is a major virulence factor for Candida albicans and a challenge for treatment. Most current antifungals have proved ineffective in eradicating infections attributed to biofilms. The biofilm structure protects Candida species against antifungals and provides a way for them to evade host immune systems. This leads to a very distinct inflammatory response compared to that seen in planktonic infections. Previously, we showed the superior efficacy of dl-2-hydroxyisocaproic acid (HICA) against various bacteria and fungi. However, the immunomodulatory properties of HICA have not been studied. Our aim was to investigate the potential anti-inflammatory response to HICA in vivo. We hypothesized that HICA reduces the levels of immune mediators and attenuates the inflammatory response. In a murine model, a robust biofilm was formed for 5 days in a diffusion chamber implanted underneath mouse skin. The biofilm was treated for 12 h with HICA, while caspofungin and phosphate-buffered saline (PBS) were used as controls. The pathophysiology and immunoexpression in the tissues surrounding the chamber were determined by immunohistochemistry. Histopathological examination showed an attenuated inflammatory response together with reduced expression of matrix metalloproteinase 9 (MMP-9) and myeloperoxidase (MPO) compared to those of chambers containing caspofungin and PBS. Interestingly, the expression of developmental endothelial locus 1 (Del-1), an antagonist of neutrophil extravasation, increased after treatment with HICA. Considering its anti-inflammatory and antimicrobial activity, HICA may have enormous therapeutic potential in the treatment of chronic biofilm infections and inflammation, such as those seen with chronic wounds. PMID:24990903

  3. Fatty acid-binding protein 5 limits the anti-inflammatory response in murine macrophages.

    PubMed

    Moore, Sherri M; Holt, Vivian V; Malpass, Lillie R; Hines, Ian N; Wheeler, Michael D

    2015-10-01

    The beginning stages of liver damage induced by various etiologies (i.e. high fat diet, alcohol consumption, toxin exposure) are characterized by abnormal accumulation of lipid in liver. Alterations in intracellular lipid transport, storage, and metabolism accompanied by cellular insult within the liver play an important role in the pathogenesis of liver disease, often involving a sustained inflammatory response. The intracellular lipid transporter, fatty acid binding protein 5 (FABP5), is highly expressed in macrophages and may play an important role in the hepatic inflammatory response after endotoxin exposure in mice. This study tested the hypothesis that FABP5 regulates macrophage response to LPS in male C57bl/6 (wild type) and FABP5 knockout mice, both in vitro and in vivo. Treatment with LPS revealed that loss of FABP5 enhances the number of hepatic F4/80(+) macrophages in the liver despite limited liver injury. Conversely, FABP5 knock out mice display higher mRNA levels of anti-inflammatory cytokines IL-10, arginase, YM-1, and Fizz-1 in liver compared to wild type mice. Bone marrow derived macrophages stimulated with inflammatory (LPS and IFN-γ) or anti-inflammatory (IL-4) mediators also showed significantly higher expression of anti-inflammatory/regulatory factors. These findings reveal a regulatory role of FABP5 in the acute inflammatory response to LPS-induced liver injury, which is consistent with the principle finding that FABP5 is a regulator of macrophage phenotype. Specifically, these findings demonstrate that loss of FABP5 promotes a more anti-inflammatory response. PMID:26105806

  4. Transient responses of phosphoric acid fuel cell power plant system. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Lu, Cheng-Yi

    1983-01-01

    An analytical and computerized study of the steady state and transient response of a phosphoric acid fuel cell (PAFC) system was completed. Parametric studies and sensitivity analyses of the PAFC system's operation were accomplished. Four non-linear dynamic models of the fuel cell stack, reformer, shift converters, and heat exchangers were developed based on nonhomogeneous non-linear partial differential equations, which include the material, component, energy balance, and electrochemical kinetic features. Due to a lack of experimental data for the dynamic response of the components only the steady state results were compared with data from other sources, indicating reasonably good agreement. A steady state simulation of the entire system was developed using, nonlinear ordinary differential equations. The finite difference method and trial-and-error procedures were used to obtain a solution. Using the model, a PAFC system, that was developed under NASA Grant, NCC3-17, was improved through the optimization of the heat exchanger network. Three types of cooling configurations for cell plates were evaluated to obtain the best current density and temperature distributions. The steady state solutions were used as the initial conditions in the dynamic model. The transient response of a simplified PAFC system, which included all of the major components, subjected to a load change was obtained. Due to the length of the computation time for the transient response calculations, analysis on a real-time computer was not possible. A simulation of the real-time calculations was developed on a batch type computer. The transient response characteristics are needed for the optimization of the design and control of the whole PAFC system. All of the models, procedures and simulations were programmed in Fortran and run on IBM 370 computers at Cleveland State University and the NASA Lewis Research Center.

  5. Electrophysiological responses of Xenopus oocytes to amino acids: criteria for expression of injected mRNA coding chemoreceptors.

    PubMed

    Etoh, M; Yoshii, K

    1994-10-01

    Responses of endogenous transporters/receptors of Xenopus oocytes to L-alanine, L-arginine, L-leucine and L-serine were investigated under voltage clamp conditions. (a) Concentration-response relations for the amino acids followed Langmuir's adsorption isotherm. (b) The neutral amino acids required Na+ to elicit the responses, whereas L-arginine did not. (c) The responses to L-alanine decreased with decreasing pH and became undetectable at pH 5.5. The present experiments supply criteria to judge if the oocytes translate exogenous mRNA coding taste or olfactory receptor proteins for the amino acids, the best characterized stimuli, especially in fishes. PMID:7956120

  6. Cauliflower mosaic virus Protein P6 Inhibits Signaling Responses to Salicylic Acid and Regulates Innate Immunity

    PubMed Central

    Love, Andrew J.; Geri, Chiara; Laird, Janet; Carr, Craig; Yun, Byung-Wook; Loake, Gary J.; Tada, Yasuomi; Sadanandom, Ari; Milner, Joel J.

    2012-01-01

    Cauliflower mosaic virus (CaMV) encodes a multifunctional protein P6 that is required for translation of the 35S RNA and also acts as a suppressor of RNA silencing. Here we demonstrate that P6 additionally acts as a pathogenicity effector of an unique and novel type, modifying NPR1 (a key regulator of salicylic acid (SA)- and jasmonic acid (JA)-dependent signaling) and inhibiting SA-dependent defence responses We find that that transgene-mediated expression of P6 in Arabidopsis and transient expression in Nicotiana benthamiana has profound effects on defence signaling, suppressing expression of representative SA-responsive genes and increasing expression of representative JA-responsive genes. Relative to wild-type Arabidopsis P6-expressing transgenics had greatly reduced expression of PR-1 following SA-treatment, infection by CaMV or inoculation with an avirulent bacterial pathogen Pseudomonas syringae pv tomato (Pst). Similarly transient expression in Nicotiana benthamiana of P6 (including a mutant form defective in translational transactivation activity) suppressed PR-1a transcript accumulation in response to Agrobacterium infiltration and following SA-treatment. As well as suppressing the expression of representative SA-regulated genes, P6-transgenic Arabidopsis showed greatly enhanced susceptibility to both virulent and avirulent Pst (titres elevated 10 to 30-fold compared to non-transgenic controls) but reduced susceptibility to the necrotrophic fungus Botrytis cinerea. Necrosis following SA-treatment or inoculation with avirulent Pst was reduced and delayed in P6-transgenics. NPR1 an important regulator of SA/JA crosstalk, was more highly expressed in the presence of P6 and introduction of the P6 transgene into a transgenic line expressing an NPR1:GFP fusion resulted in greatly increased fluorescence in nuclei even in the absence of SA. Thus in the presence of P6 an inactive form of NPR1 is mislocalized in the nucleus even in uninduced plants. These results

  7. Responses of the murine esophageal microcirculation to acute exposure to alkali, acid, or hypochlorite

    PubMed Central

    Osman, M.; Russell, J.; Shukla, D.; Moghadamfalahi, M.; Granger, D.N.

    2008-01-01

    Background/Purpose Although ingestion of alkali- and/or hypochlorite-based household cleaners as well as strong acids remain a major cause of esophageal wall injury, little is known about the mechanisms that underlie the injury response to these toxic agents. This study examined the roles of vascular dysfunction and inflammation to the esophageal injury response to different caustic substances in mice. Methods The esophageal responses to NaOH (10%, 5% & 2.5%), KOH (10%, 5%, & 2.5%), NaOCl (5.25%), and HCl (10%, pH=2) were evaluated by intravital videomicroscopy, and histopathology. Intravital microscopy was used to monitor changes in the diameter of arterioles and venules, the adhesion and movement of leukocytes in venules, and time of cessation of arteriolar blood flow in mouse esophagus. The esophageal mucosa was exposed to caustic substances for 0–60 minutes prior to evaluation. Results The higher concentrations of NaOH and KOH elicited rapid stasis in both arterioles and venules, which was accompanied by arteriolar constriction and thrombosis. An accumulation of adherent leukocytes in venules was not observed with any agent. Histopathologic evaluation revealed marked cellular and interstitial edema in the mucosa with alkali, while HCl and NaOCl decreased the thickness epithelial layer. Conclusion These findings suggest that ischemia and thrombosis are dominant processes, while inflammation is less important, in the pathogenesis of acute corrosive injury to the esophageal mucosa. PMID:18779005

  8. Cell type-specific response to high intracellular loading of polyacrylic acid-coated magnetic nanoparticles.

    PubMed

    Lojk, Jasna; Bregar, Vladimir B; Rajh, Maruša; Miš, Katarina; Kreft, Mateja Erdani; Pirkmajer, Sergej; Veranič, Peter; Pavlin, Mojca

    2015-01-01

    Magnetic nanoparticles (NPs) are a special type of NP with a ferromagnetic, electron-dense core that enables several applications such as cell tracking, hyperthermia, and magnetic separation, as well as multimodality. So far, superparamagnetic iron oxide NPs (SPIONs) are the only clinically approved type of metal oxide NPs, but cobalt ferrite NPs have properties suitable for biomedical applications as well. In this study, we analyzed the cellular responses to magnetic cobalt ferrite NPs coated with polyacrylic acid (PAA) in three cell types: Chinese Hamster Ovary (CHO), mouse melanoma (B16) cell line, and primary human myoblasts (MYO). We compared the internalization pathway, intracellular trafficking, and intracellular fate of our NPs using fluorescence and transmission electron microscopy (TEM) as well as quantified NP uptake and analyzed uptake dynamics. We determined cell viability after 24 or 96 hours' exposure to increasing concentrations of NPs, and quantified the generation of reactive oxygen species (ROS) upon 24 and 48 hours' exposure. Our NPs have been shown to readily enter and accumulate in cells in high quantities using the same two endocytic pathways; mostly by macropinocytosis and partially by clathrin-mediated endocytosis. The cell types differed in their uptake rate, the dynamics of intracellular trafficking, and the uptake capacity, as well as in their response to higher concentrations of internalized NPs. The observed differences in cell responses stress the importance of evaluation of NP-cell interactions on several different cell types for better prediction of possible toxic effects on different cell and tissue types in vivo. PMID:25733835

  9. Dietary polyunsaturated fatty acids from flaxseed affect immune responses of dairy sheep around parturition.

    PubMed

    Caroprese, Mariangela; Ciliberti, Maria Giovanna; Albenzio, Marzia; Annicchiarico, Giovanni; Sevi, Agostino

    2015-11-15

    The objective of the study was to characterize the immune profile of dairy ewes fed flaxseed, rich in polyunsaturated fatty acids (PUFA), around parturition. The hypothesis to be verified was that a physiological stressor, such as parturition, could be overcome with a nutritional manipulation in the diet of the animal in order to guarantee welfare of animals and to sustain their immune responses. Twenty Comisana ewes were divided in two groups (10 ewes/group), and fed a supplementation of whole flaxseed in the diet (FS group) or no supplementation (CON group). Blood samples were collected at parturition and then 7, 14, 21, 28, and 42 day post partum. Plasma samples were used to assess the humoral immune response after ovalbumin (OVA) immunization. At parturition, at 14 day, and 42 day post partum the level of plasma cytokines was assessed. The sheep showed a reduced responsiveness to OVA immunization. In FS ewes the IL-6 level remained unchanged until 14 day post partum and then significantly decreased from 14 day to 42 day post partum. IL-10 level was significantly higher in FS ewes than in CON ewes at 14 day. At parturition IL-1β level was significantly lower in FS ewes than in CON ewes and significantly decreased in both groups from parturition to 42 day. In conclusion, PUFA from flaxseed, as supplement in the diet of ewes around parturition can modulate sheep immune reactivity by influencing cytokine production. PMID:26347035

  10. Involvement of endogenous salicylic acid in iron-deficiency responses in Arabidopsis.

    PubMed

    Shen, Chenjia; Yang, Yanjun; Liu, Kaidong; Zhang, Lei; Guo, Hong; Sun, Tao; Wang, Huizhong

    2016-07-01

    Several phytohormones have been demonstrated to be involved in iron (Fe) homeostasis. We took advantage of a salicylic acid (SA) biosynthesis defective mutant phytoalexin deficient 4 (pad4: T-DNA Salk_089936) to explore the possible effects of endogenous SA on the morphological and physiological responses to Fe deprivation. The morphological and physiological analysis was carried out between Col-0 and the pad4 mutant. Under an Fe-deficiency treatment, Col-0 showed more severe leaf chlorosis and root growth inhibition compared with the pad4 mutant. The soluble Fe concentrations were significantly higher in pad4 than in Col-0 under the Fe-deficiency treatment. Fe deficiency significantly induced SA accumulation in Col-0 and the loss-of-function of PAD4 blocked this process. The requirement of endogenous SA accumulation for Fe-deficiency responses was confirmed using a series of SA biosynthetic mutants and transgenic lines. Furthermore, a comparative RNA sequencing analysis of the whole seedling transcriptomes between Col-0 and the pad4 mutant was also performed. Based on the transcriptome data, the expression levels of many auxin- and ethylene-response genes were altered in pad4 compared with Col-0. Fe deficiency increases SA contents which elevates auxin and ethylene signalling, thereby activating Fe translocation via the bHLH38/39-mediated transcriptional regulation of downstream Fe genes. PMID:27208542

  11. Cell type-specific response to high intracellular loading of polyacrylic acid-coated magnetic nanoparticles

    PubMed Central

    Lojk, Jasna; Bregar, Vladimir B; Rajh, Maruša; Miš, Katarina; Kreft, Mateja Erdani; Pirkmajer, Sergej; Veranič, Peter; Pavlin, Mojca

    2015-01-01

    Magnetic nanoparticles (NPs) are a special type of NP with a ferromagnetic, electron-dense core that enables several applications such as cell tracking, hyperthermia, and magnetic separation, as well as multimodality. So far, superparamagnetic iron oxide NPs (SPIONs) are the only clinically approved type of metal oxide NPs, but cobalt ferrite NPs have properties suitable for biomedical applications as well. In this study, we analyzed the cellular responses to magnetic cobalt ferrite NPs coated with polyacrylic acid (PAA) in three cell types: Chinese Hamster Ovary (CHO), mouse melanoma (B16) cell line, and primary human myoblasts (MYO). We compared the internalization pathway, intracellular trafficking, and intracellular fate of our NPs using fluorescence and transmission electron microscopy (TEM) as well as quantified NP uptake and analyzed uptake dynamics. We determined cell viability after 24 or 96 hours’ exposure to increasing concentrations of NPs, and quantified the generation of reactive oxygen species (ROS) upon 24 and 48 hours’ exposure. Our NPs have been shown to readily enter and accumulate in cells in high quantities using the same two endocytic pathways; mostly by macropinocytosis and partially by clathrin-mediated endocytosis. The cell types differed in their uptake rate, the dynamics of intracellular trafficking, and the uptake capacity, as well as in their response to higher concentrations of internalized NPs. The observed differences in cell responses stress the importance of evaluation of NP–cell interactions on several different cell types for better prediction of possible toxic effects on different cell and tissue types in vivo. PMID:25733835

  12. Streptozotocin induced activation of oxidative stress responsive splenic cell signaling pathways: Protective role of arjunolic acid

    SciTech Connect

    Manna, Prasenjit; Ghosh, Jyotirmoy; Das, Joydeep

    2010-04-15

    Present study investigates the beneficial role of arjunolic acid (AA) against the alteration in the cytokine levels and simultaneous activation of oxidative stress responsive signaling pathways in spleen under hyperglycemic condition. Diabetes was induced by injection of streptozotocin (STZ) (at a dose of 70 mg/kg body weight, injected in the tail vain). STZ administration elevated the levels of IL-2 as well as IFN-gamma and attenuated the level of TNF-alpha in the sera of diabetic animals. In addition, hyperglycemia is also associated with the increased production of intracellular reactive intermediates resulting with the elevation in lipid peroxidation, protein carbonylation and reduction in intracellular antioxidant defense. Investigating the oxidative stress responsive cell signaling pathways, increased expressions (immunoreactive concentrations) of phosphorylated p65 as well as its inhibitor protein phospho IkappaBalpha and phosphorylated mitogen activated protein kinases (MAPKs) have been observed in diabetic spleen tissue. Studies on isolated splenocytes revealed that hyperglycemia caused disruption of mitochondrial membrane potential, elevation in the concentration of cytosolic cytochrome c as well as activation of caspase 3 leading to apoptotic cell death. Histological examination revealed that diabetic induction depleted the white pulp scoring which is in agreement with the reduced immunological response. Treatment with AA prevented the hyperglycemia and its associated pathogenesis in spleen tissue. Results suggest that AA might act as an anti-diabetic and immunomodulatory agent against hyperglycemia.

  13. Is Protein Phosphatase Inhibition Responsible for the Toxic Effects of Okadaic Acid in Animals?

    PubMed Central

    Munday, Rex

    2013-01-01

    Okadaic acid (OA) and its derivatives, which are produced by dinoflagellates of the genera Prorocentrum and Dinophysis, are responsible for diarrhetic shellfish poisoning in humans. In laboratory animals, these toxins cause epithelial damage and fluid accumulation in the gastrointestinal tract, and at high doses, they cause death. These substances have also been shown to be tumour promoters, and when injected into the brains of rodents, OA induces neuronal damage reminiscent of that seen in Alzheimer’s disease. OA and certain of its derivatives are potent inhibitors of protein phosphatases, which play many roles in cellular metabolism. In 1990, it was suggested that inhibition of these enzymes was responsible for the diarrhetic effect of these toxins. It is now repeatedly stated in the literature that protein phosphatase inhibition is not only responsible for the intestinal effects of OA and derivatives, but also for their acute toxic effects, their tumour promoting activity and their neuronal toxicity. In the present review, the evidence for the involvement of protein phosphatase inhibition in the induction of the toxic effects of OA and its derivatives is examined, with the conclusion that the mechanism of toxicity of these substances requires re-evaluation. PMID:23381142

  14. Salvianolic acid B ameliorates CNS autoimmunity by suppressing Th1 responses.

    PubMed

    Dong, Zhihui; Ma, Dihui; Gong, Ye; Yu, Tingmin; Yao, Gang

    2016-04-21

    Experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis (MS), is a Th1 and Th17 cell-mediated CNS autoimmune disease. Therefore, immune regulation is a key target for therapy. Salvianolic acid B (Sal B) is a major water-soluble bioactive component of the famous traditional Chinese medicine Salvia miltiorrhiza, which is notable for its anti-oxidative and anti-inflammatory effects. Thus Sal B, by impairing Th1 or Th17 responses in EAE/MS, might ameliorate the crippling symptoms. Here we show that the intraperitoneal administration of 30mg/kg Sal B daily for 14 days after the onset of MOG-induced EAE in mice effectively reduced its severity. Additionally, Sal B treatment downgraded the infiltration of inflammatory cells, limited astrogliosis and blocked Th1 responses other than that of Th17. These results indicated that Sal B may serve as an effective therapeutic agent for MS/EAE by inhibiting Th1 cell responses. PMID:26777627

  15. Jasmonic acid carboxyl methyltransferase regulates development and herbivory-induced defense response in rice.

    PubMed

    Qi, Jinfeng; Li, Jiancai; Han, Xiu; Li, Ran; Wu, Jianqiang; Yu, Haixin; Hu, Lingfei; Xiao, Yutao; Lu, Jing; Lou, Yonggen

    2016-06-01

    Jasmonic acid (JA) and related metabolites play a key role in plant defense and growth. JA carboxyl methyltransferase (JMT) may be involved in plant defense and development by methylating JA to methyl jasmonate (MeJA) and thus influencing the concentrations of JA and related metabolites. However, no JMT gene has been well characterized in monocotyledon defense and development at the molecular level. After we cloned a rice JMT gene, OsJMT1, whose encoding protein was localized in the cytosol, we found that the recombinant OsJMT1 protein catalyzed JA to MeJA. OsJMT1 is up-regulated in response to infestation with the brown planthopper (BPH; Nilaparvata lugens). Plants in which OsJMT1 had been overexpressed (oe-JMT plants) showed reduced height and yield. These oe-JMT plants also exhibited increased MeJA levels but reduced levels of herbivore-induced JA and jasmonoyl-isoleucine (JA-Ile). The oe-JMT plants were more attractive to BPH female adults but showed increased resistance to BPH nymphs, probably owing to the different responses of BPH female adults and nymphs to the changes in levels of H2 O2 and MeJA in oe-JMT plants. These results indicate that OsJMT1, by altering levels of JA and related metabolites, plays a role in regulating plant development and herbivore-induced defense responses in rice. PMID:26466818

  16. Protocatechuic Acid Restores Vascular Responses in Rats With Chronic Diabetes Induced by Streptozotocin.

    PubMed

    Semaming, Yoswaris; Kukongviriyapan, Upa; Kongyingyoes, Bunkerd; Thukhammee, Wipawee; Pannangpetch, Patchareewan

    2016-02-01

    Oxidative stress has been shown to play an important role in development of vascular dysfunction in diabetes. Protocatechuic acid (PCA) has been reported to exert antioxidant and anti-hyperglycemic activities. Diabetes was induced in male Sprague-Dawley rats by a single intraperitoneal injection of 50 mg/kg streptozotocin (STZ). The rats were maintained in a state of hyperglycemia for 12 weeks. Then, PCA (50 or 100 mg/kg/day) was administered orally or insulin (4 U/kg/day) was subcutaneous injected to the rats for 6 weeks. Blood pressure, vascular responses to vasoactive agents, vascular superoxide production, blood glucose, insulin, malondialdehyde, nitric oxide and antioxidant enzymes were examined. The diabetic rats showed weight loss, insulin deficiency, hyperglycemia, increased oxidative stress, decreased plasma nitric oxide, elevated blood pressure, increased vascular response to phenylephrine and decreased vascular responses to acetylcholine and sodium nitroprusside. PCA significantly decreased blood glucose and oxidative stress, and increased plasma nitric oxide in diabetic rats. Interestingly, PCA treatment restored blood pressure and vascular reactivity, and antioxidant enzyme activity diabetic rats. This study provides the first evidence of the efficacy of PCA in restoring the vascular reactivity of diabetic rats. The mechanism of action may be associated with an alleviation of oxidative stress. PMID:26575211

  17. Different sources of dietary n-6 polyunsaturated fatty acids and their effects on antibody responses in chickens.

    PubMed

    Parmentier, H K; Awati, A; Nieuwland, M G B; Schrama, J W; Sijben, J W C

    2002-09-01

    1. Effects of linoleic and linolenic acid provided via different oil sources on total antibody (Ab) titres, Ab isotypes after primary and secondary immunisation, and cutaneous hypersensitivity (CH) responses to bovine serum albumin (BSA) and maleyl-BSA, respectively, were studied in pullets fed on one of 4 diets. The diets were the basal control diet enriched with either sunflower oil or safflower oil as sources of linoleic acid, and linseed oil as a source of linolenic acid, tested against a control diet supplemented with animal fat. 2. Total Ab and immunoglobulin (Ig) isotype responses to BSA were affected by diet after primary, and diet x immunisation effects after secondary immunisation. Higher total Ab and IgG titres to BSA were found especially after primary immunisation in birds given the sunflower oil enriched diet, whereas birds given sunflower oil mounted significantly lower IgM titres to BSA after primary and secondary immunisation. The antibody responses to maleyl-BSA were affected by diet after primary, and immunisation x diet interactions after secondary immunisation. Sunflower oil enhanced total and IgG Ab titres to maleyl-BSA after primary immunisation, but decreased IgM titres to maleyl-BSA after primary and secondary immunisation. Cutaneous hypersensitivity responses to BSA and maleyl-BSA were not affected by the diet. 3. It is concluded that modulation of the magnitude and isotype of Ab responses of poultry to T cell-dependent antigens is affected not only by type of essential fatty acids, but also by their source. In the present study the n-6 source, sunflower oil, showed strong enhancement of primary Ab responses, directed to both Th2 and Th1 antigens. On the other hand, the different effects of safflower oil imply that constituents other than n-6 acids within dietary plant oils may affect immune responsiveness. 4. The relationship between magnitude and isotype of Ab responsiveness, type of antigen, and essential fatty acids is discussed. PMID

  18. Adaptive response of Rhodococcus opacus PWD4 to salt and phenolic stress on the level of mycolic acids.

    PubMed

    de Carvalho, Carla C C R; Fischer, Martin A; Kirsten, Sandra; Würz, Birgit; Wick, Lukas Y; Heipieper, Hermann J

    2016-12-01

    Mycolata form a group of Gram-positive bacteria with unique cell envelope structures that are known for their high tolerance against antibiotics and both aromatic and aliphatic hydrocarbons. An important part of the unique surface structure of the mycolata is the presence of long chain α-alkyl-β-hydroxy fatty acids, the mycolic acids. In order to investigate the adaptive changes in the mycolic acid composition, we investigated the composition of mycolic acids during the response both to osmotic stress caused by NaCl and to 4-chlorophenol in Rhodococcus opacus PWD4. This bacterium was chosen as it is known to adapt to different kinds of stresses. In addition, it is a potential biocatalyst in bioremediation as well as for biotechnological applications. In the present study, cells of R. opacus PWD4, grown in liquid cultures, responded to toxic concentrations of NaCl by increasing the ratio between mycolic acids and membrane phospholipid fatty acids (MA/PLFA-ratio). Cells reacted to both NaCl and 4-chlorophenol by decreasing both the average chain length and the unsaturation index of their mycolic acids. These changes in mycolic acid composition correlated with increases in cell surface hydrophobicity and saturation of membrane fatty acids, demonstrating the relation between mycolic acid and phospholipid synthesis and their contribution to cell surface properties of R. opacus PWD4. PMID:27620730

  19. The ObgE/CgtA GTPase influences the stringent response to amino acid starvation in Escherichia coli

    PubMed Central

    Persky, Nicole S.; Ferullo, Daniel J.; Cooper, Deani L.; Moore, Hayley R.; Lovett, Susan T.

    2009-01-01

    The stringent response is important for bacterial survival under stressful conditions, such as amino acid starvation, and is characterized by the accumulation of ppGpp and pppGpp. ObgE (CgtA, YhbZ) is an essential conserved GTPase in Escherichia coli and several observations have implicated the protein in the control of the stringent response. However, consequences of the protein on specific responses to amino acid starvation have not been noted. We show that ObgE binds to ppGpp with biologically relevant affinity in vitro, implicating ppGpp as an in vivo ligand of ObgE. ObgE mutants increase the ratio of pppGpp to ppGpp within the cell during the stringent response. These changes are correlated with a delayed inhibition of DNA replication by the stringent response, delayed resumption of DNA replication after release, as well as a decreased survival to the response to amino acid deprivation. With this data, we place ObgE as an active effector of the response to amino acid starvation in vivo. Our data correlate the pppGpp/ppGpp ratio with DNA replication control under bacterial starvation conditions suggesting a possible role for the relative balance of these two nucleotides. PMID:19555460

  20. L-Amino Acids Elicit Diverse Response Patterns in Taste Sensory Cells: A Role for Multiple Receptors

    PubMed Central

    Pal Choudhuri, Shreoshi; Delay, Rona J.; Delay, Eugene R.

    2015-01-01

    Umami, the fifth basic taste, is elicited by the L-amino acid, glutamate. A unique characteristic of umami taste is the response potentiation by 5’ ribonucleotide monophosphates, which are also capable of eliciting an umami taste. Initial reports using human embryonic kidney (HEK) cells suggested that there is one broadly tuned receptor heterodimer, T1r1+T1r3, which detects L-glutamate and all other L-amino acids. However, there is growing evidence that multiple receptors detect glutamate in the oral cavity. While much is understood about glutamate transduction, the mechanisms for detecting the tastes of other L-amino acids are less well understood. We used calcium imaging of isolated taste sensory cells and taste cell clusters from the circumvallate and foliate papillae of C57BL/6J and T1r3 knockout mice to determine if other receptors might also be involved in detection of L-amino acids. Ratiometric imaging with Fura-2 was used to study calcium responses to monopotassium L-glutamate, L-serine, L-arginine, and L-glutamine, with and without inosine 5’ monophosphate (IMP). The results of these experiments showed that the response patterns elicited by L-amino acids varied significantly across taste sensory cells. L-amino acids other than glutamate also elicited synergistic responses in a subset of taste sensory cells. Along with its role in synergism, IMP alone elicited a response in a large number of taste sensory cells. Our data indicate that synergistic and non-synergistic responses to L-amino acids and IMP are mediated by multiple receptors or possibly a receptor complex. PMID:26110622

  1. Cellular Interactions and Immune Response of Spherical Nucleic Acid (SNA) Nanoconjugates

    NASA Astrophysics Data System (ADS)

    Massich, Matthew David

    Spherical nucleic acid (SNA) nanoconjugates consist of a densely packed monolayer shell of highly-oriented oligonucleotides covalently bound to a gold nanoparticle core. The nanoconjugates exhibit several important qualities, which make them useful for various biological applications, such as antisense gene regulation strategies and the intracellular detection of biomolecules. The focus of this thesis was to characterize the nanoconjugates interaction with cultured cells and specifically the immune response to their intracellular presence. The immune response of macrophage cells to internalized nanoconjugates was studied, and due to the dense functionalization of oligonucleotides on the surface of the nanoparticle and the resulting high localized salt concentration the innate immune response to the nanoconjugates is ˜25-fold less when compared to a lipoplex carrying the same sequence. Additionally, genome-wide expression profiling was used to study the biological response of cultured cells to the nanoconjugates. The biological response of HeLa cells to gold nanoparticles stabilized by weakly bound ligands was significant, yet when these same nanoparticles were stably functionalized with covalently attached oligonucleotides the cells showed no measurable response. In human keratinocytes, the oligonucleotide sequences caused 427 genes to be differentially expressed when complexed with Dharmafect, but when the oligonucleotides were conjugated to nanoparticles only 7 genes were differentially expressed. Beyond characterizing the cellular interactions and immune response of the nanoconjugates, the optimal length of siRNA (from 19--34 base pairs) that induces the most gene knockdown while maintaining limited immune activation was determined to be 24 base pairs. Further, the SNAs were shown to be useful as a potential antiviral gene therapy by demonstrating approximately 50% knockdown of the Ebola VP35 gene. Lastly, a scanning probe-enabled method was used to rapidly

  2. Responses mediated by excitatory amino acid receptors in solitary retinal ganglion cells from rat.

    PubMed Central

    Aizenman, E; Frosch, M P; Lipton, S A

    1988-01-01

    1. The pharmacological properties of excitatory amino acid responses on ganglion cells dissociated from the rat retina were examined with the use of the whole-cell voltage-clamp technique. 2. L-Glutamate at a concentration of 50 microM produced inward non-desensitizing currents at negative holding potentials in nearly every cell tested (83%, n = 18) In physiological solutions, L-glutamate responses reversed at approximately -9 mV, and higher concentrations of this agonist introduced a desensitizing component to the response. 3. At negative holding potentials, kainate (25-125 microM) produced inward currents in all of the cells tested (n = 37). These currents never desensitized, even at high agonist concentrations, and reversed near -6 mV. Currents induced by 50 microM-kainate were reversibly antagonized by kynurenate (100-300 microM) but not by 100 microM-2-amino-5-phosphonovalerate (APV). 4. Quisqualate generated smaller, non-desensitizing currents in only 50% of the cells tested (n = 38). Quisqualate responses reversed in polarity near -4 mV and were maximal at an agonist dose of 25 microM, with higher concentrations introducing a rapidly desensitizing component without a detectable increase in amplitude. Currents produced by quisqualate at a concentration of 50 microM were not antagonized by either 750 microM-kynurenate or 100 microM-APV. 5. N-Methyl-D-aspartate (NMDA) produced inward currents at negative holding potentials in 68% of the cells tested (n = 31), but only when magnesium was excluded from the extracellular medium. NMDA currents were non-desensitizing at agonist concentrations of up to 200 microM, with higher concentrations introducing a rapidly desensitizing component. NMDA (200 microM) responses were blocked by APV (100 microM) and kynurenate (300 microM) and reversed near -1 mV. 6. Responses generated by kainate (50-125 microM) were antagonized by quisqualate (30-250 microM). This antagonism occurred even in cells having no measurable response to

  3. Ascorbic acid accumulates as a defense response to Turnip mosaic virus in resistant Brassica rapa cultivars.

    PubMed

    Fujiwara, Ayaka; Togawa, Satoko; Hikawa, Takahiro; Matsuura, Hideyuki; Masuta, Chikara; Inukai, Tsuyoshi

    2016-07-01

    We initially observed that Brassica rapa cultivars containing the Turnip mosaic virus (TuMV) resistance gene, Rnt1-1, accumulated a high level of endogenous ascorbic acid (AS) and dehydroascobic acid (DHA) when infected with TuMV. We here hypothesized a possible contribution of an elevated level of AS+DHA (TAA) to the Rnt1-1-mediated resistance, and conducted a series of experiments using B. rapa and Arabidopsis plants. The application of l-galactose (the key substrate in AS synthesis) to a susceptible cultivar could increase the TAA level ~2-fold, and simultaneously lead to some degree of enhanced viral resistance. To confirm some positive correlation between TAA levels and viral resistance, we analyzed two Arabidopsis knockout mutants (ao and vtc1) in the AS pathways; the TAA levels were significantly increased and decreased in ao and vtc1 plants, respectively. While the ao plants showed enhanced resistance to TuMV, vtc1 plants were more susceptible than the control, supporting our hypothesis. When we analyzed the expression profiles of the genes involved in the AS pathways upon TuMV infection, we found that the observed TAA increase was mainly brought about by the reduction of AS oxidation and activation of AS recycling. We then investigated the secondary signals that regulate endogenous TAA levels in response to viral infection, and found that jasmonic acid (JA) might play an important role in TAA accumulation. In conclusion, we reason that the elevated TAA accumulation in B. rapa plants would be at least partly mediated by the JA-dependent signaling pathway and may significantly contribute to viral resistance. PMID:27255930

  4. Different responses of two Mosla species to potassium limitation in relation to acid rain deposition*

    PubMed Central

    Wang, Meng; Gu, Bao-jing; Ge, Ying; Liu, Zhen; Jiang, De-an; Chang, Scott X.; Chang, Jie

    2009-01-01

    The increasingly serious problem of acid rain is leading to increased potassium (K) loss from soils, and in our field investigation, we found that even congenerically relative Mosla species show different tolerance to K-deficiency. A hydroponic study was conducted on the growth of two Mosla species and their morphological, physiological and stoichiometric traits in response to limited (0.35 mmol K/L), normal (3.25 mmol K/L) and excessive (6.50 mmol K/L) K concentrations. Mosla hangchowensis is an endangered plant, whereas Mosla dianthera a widespread weed. In the case of M. hangchowensis, in comparison with normal K concentration, K-limitation induced a significant reduction in net photosynthetic rate (P n), soluble protein content, and superoxide dismutase (SOD) activity, but an increase in malondialdehyde (MDA) concentration. However, leaf mass ratio (LMR) and root mass ratio (RMR) were changed little by K-limitation. In contrast, for M. dianthera, K-limitation had little effect on P n, soluble protein content, SOD activity, and MDA concentration, but increased LMR and RMR. Critical values of N (nitrogen):K and K:P (phosphorus) ratios in the shoots indicated that limitation in acquiring K occurred under K-limited conditions for M. hangchowensis but not for M. dianthera. We found that low K content in natural habitats was a restrictive factor in the growth and distribution of M. hangchowensis, and soil K-deficiency caused by acid rain worsened the situation of M. hangchowensis, while M. dianthera could well acclimate to the increasing K-deficiency. We suggest that controlling the acid rain and applying K fertilizers may be an effective way to rescue the endangered M. hangchowensis. PMID:19650194

  5. The Polyunsaturated Fatty Acids Arachidonic Acid and Docosahexaenoic Acid Induce Mouse Dendritic Cells Maturation but Reduce T-Cell Responses In Vitro

    PubMed Central

    Carlsson, Johan A.; Wold, Agnes E.; Sandberg, Ann-Sofie; Östman, Sofia M.

    2015-01-01

    Long-chain polyunsaturated fatty acids (PUFAs) might regulate T-cell activation and lineage commitment. Here, we measured the effects of omega-3 (n-3), n-6 and n-9 fatty acids on the interaction between dendritic cells (DCs) and naïve T cells. Spleen DCs from BALB/c mice were cultured in vitro with ovalbumin (OVA) with 50 μM fatty acids; α-linolenic acid, arachidonic acid (AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), linoleic acid or oleic acid and thereafter OVA-specific DO11.10 T cells were added to the cultures. Fatty acids were taken up by the DCs, as shown by gas chromatography analysis. After culture with arachidonic acid or DHA CD11c+ CD11b+ and CD11c+ CD11bneg DCs expressed more CD40, CD80, CD83, CD86 and PDL-1, while IAd remained unchanged. However, fewer T cells co-cultured with these DCs proliferated (CellTrace Violetlow) and expressed CD69 or CD25, while more were necrotic (7AAD+). We noted an increased proportion of T cells with a regulatory T cell (Treg) phenotype, i.e., when gating on CD4+ FoxP3+ CTLA-4+, CD4+ FoxP3+ Helios+ or CD4+ FoxP3+ PD-1+, in co-cultures with arachidonic acid- or DHA-primed DCs relative to control cultures. The proportion of putative Tregs was inversely correlated to T-cell proliferation, indicating a suppressive function of these cells. With arachidonic acid DCs produced higher levels of prostaglandin E2 while T cells produced lower amounts of IL-10 and IFNγ. In conclusion arachidonic acid and DHA induced up-regulation of activation markers on DCs. However arachidonic acid- and DHA-primed DCs reduced T-cell proliferation and increased the proportion of T cells expressing FoxP3, indicating that these fatty acids can promote induction of regulatory T cells. PMID:26619195

  6. Cullin 3 mediates SRC-3 ubiquitination and degradation to control the retinoic acid response

    PubMed Central

    Ferry, Christine; Gaouar, Samia; Fischer, Benoit; Boeglin, Marcel; Paul, Nicodeme; Samarut, Eric; Piskunov, Aleksandr; Pankotai-Bodo, Gabriella; Brino, Laurent; Rochette-Egly, Cecile

    2011-01-01

    SRC-3 is an important coactivator of nuclear receptors including the retinoic acid (RA) receptor α. Most of SRC-3 functions are facilitated by changes in the posttranslational code of the protein that involves mainly phosphorylation and ubiquitination. We recently reported that SRC-3 is degraded by the proteasome in response to RA. Here, by using an RNAi E3-ubiquitin ligase entry screen, we identified CUL-3 and RBX1 as components of the E3 ubiquitin ligase involved in the RA-induced ubiquitination and subsequent degradation of SRC-3. We also show that the RA-induced ubiquitination of SRC-3 depends on its prior phosphorylation at serine 860 that promotes binding of the CUL-3–based E3 ligase in the nucleus. Finally, phosphorylation, ubiquitination, and degradation of SRC-3 cooperate to control the dynamics of transcription. In all, this process participates to the antiproliferative effect of RA. PMID:22147914

  7. Dynamics of fatty acid vesicles in response to pH stimuli.

    PubMed

    Ikari, Keita; Sakuma, Yuka; Jimbo, Takehiro; Kodama, Atsuji; Imai, Masayuki; Monnard, Pierre-Alain; Rasmussen, Steen

    2015-08-21

    We investigate the dynamics of decanoic acid/decanoate (DA) vesicles in response to pH stimuli. Two types of dynamic processes induced by the micro-injection of NaOH solutions are sequentially observed: deformations and topological transitions. In the deformation stage, DA vesicles show a series of shape deformations, i.e., prolate-oblate-stomatocyte-sphere. In the topological transition stage, spherical DA vesicles follow either of the two pathways, pore formation and vesicle fusion. The pH stimuli modify a critical aggregation concentration of DA molecules, which causes the solubilization of DA molecules in the outer leaflet of the vesicle bilayers. This solubilization decreases the outer surface area of the vesicle, thereby increasing surface tension. A kinetic model based on area difference elasticity theory can accurately describe the dynamics of DA vesicles triggered by pH stimuli. PMID:26166464

  8. Isolation and characterization of all-trans-retinoic acid-responsive genes in the rat testis.

    PubMed

    Gaemers, I C; Van Pelt, A M; Themmen, A P; De Rooij, D G

    1998-05-01

    By way of differential screening of testis cDNA libraries from vitamin A-deficient (VAD) rats before and after administration of all-trans retinoic acid (ATRA), genes, the transcription of which was influenced by ATRA, were isolated. Most clones with an increased transcription encoded different subunits of the same mitochondrial protein complex, cytochrome c oxidase (COX). The mRNA expression of COX increased by a factor 3.9 +/- 1.5 (mean +/- SD, n = 4). This increased expression seems to reflect an increased energy demand in the ATRA-supplemented VAD testis. Also, one gene was isolated, the transcription of which was reduced to about 70% by ATRA. This gene, sulfated glycoprotein 2 (Sgp-2), is a major secretion product of Sertoli cells, the function of which is still unknown. The effect of ATRA on Sgp-2 expression may be direct, since the promoter of Sgp-2 contains a putative ATRA-responsive element (RARE). PMID:9547504

  9. Retinoic acid inhibits the cytoproliferative response to weak 50-Hz magnetic fields in neuroblastoma cells

    PubMed Central

    TRILLO, MARÍA ÁNGELES; MARTÍNEZ, MARÍA ANTONIA; CID, MARÍA ANTONIA; ÚBEDA, ALEJANDRO

    2012-01-01

    We previously reported that intermittent exposure to a 50-Hz magnetic field (MF) at 100 μT stimulates cell proliferation in the human neuroblastoma cell line NB69. The present study aimed to investigate whether the magnetic field-induced growth promotion also occurs at a lower magnetic flux density of 10 μT. To this purpose, NB69 cells were subjected for 42 h to intermittent exposure, 3 h on/3 h off, to a 50-Hz MF at a 10 or 100 μT magnetic flux density. The field exposure took place either in the presence or in the absence of the antiproliferative agent retinoic acid. At the end of the treatment and/or incubation period, the cell growth was estimated by hemocytometric counting and spectrophotometric analysis of total protein and DNA contents. Potential changes in DNA synthesis were also assessed through proliferating cell nuclear antigen (PCNA) immunolabeling. The results confirmed previously reported data that a 42-h exposure to a 50-Hz sine wave MF at 100 μT promotes cell growth in the NB69 cell line, and showed that 10 μT induces a similar proliferative response. This effect, which was significantly associated and linearly correlated with PCNA expression, was abolished by the presence of retinoic acid in the culture medium. PMID:23292364

  10. Relative quantification of phosphoproteomic changes in grapevine (Vitis vinifera L.) leaves in response to abscisic acid.

    PubMed

    Rattanakan, Supakan; George, Iniga; Haynes, Paul A; Cramer, Grant R

    2016-01-01

    In a previous transcriptomic analysis, abscisic acid (ABA) was found to affect the abundance of a number of transcripts in leaves of Cabernet Sauvignon grapevines with roots that had been exposed to 10 μm ABA for 2 h. Other work has indicated that ABA affects protein abundance and protein phosphorylation as well. In this study we investigated changes in protein abundance and phosphorylation of Cabernet Sauvignon grapevine leaves. Protein abundance was assessed by both label-free and isobaric-label quantitive proteomic methods. Each identified common proteins, but also additional proteins not found with the other method. Overall, several thousand proteins were identified and several hundred were quantified. In addition, hundreds of phosphoproteins were identified. Tens of proteins were found to be affected in the leaf after the roots had been exposed to ABA for 2 h, more than half of them were phosphorylated proteins. Many phosphosites were confirmed and several new ones were identified. ABA increased the abundance of some proteins, but the majority of the proteins had their protein abundance decreased. Many of these proteins were involved in growth and plant organ development, including proteins involved in protein synthesis, photosynthesis, sugar and amino-acid metabolism. This study provides new insights into how ABA regulates plant responses and acclimation to water deficits. PMID:27366326

  11. Relative quantification of phosphoproteomic changes in grapevine (Vitis vinifera L.) leaves in response to abscisic acid

    PubMed Central

    Rattanakan, Supakan; George, Iniga; Haynes, Paul A; Cramer, Grant R

    2016-01-01

    In a previous transcriptomic analysis, abscisic acid (ABA) was found to affect the abundance of a number of transcripts in leaves of Cabernet Sauvignon grapevines with roots that had been exposed to 10 μm ABA for 2 h. Other work has indicated that ABA affects protein abundance and protein phosphorylation as well. In this study we investigated changes in protein abundance and phosphorylation of Cabernet Sauvignon grapevine leaves. Protein abundance was assessed by both label-free and isobaric-label quantitive proteomic methods. Each identified common proteins, but also additional proteins not found with the other method. Overall, several thousand proteins were identified and several hundred were quantified. In addition, hundreds of phosphoproteins were identified. Tens of proteins were found to be affected in the leaf after the roots had been exposed to ABA for 2 h, more than half of them were phosphorylated proteins. Many phosphosites were confirmed and several new ones were identified. ABA increased the abundance of some proteins, but the majority of the proteins had their protein abundance decreased. Many of these proteins were involved in growth and plant organ development, including proteins involved in protein synthesis, photosynthesis, sugar and amino-acid metabolism. This study provides new insights into how ABA regulates plant responses and acclimation to water deficits. PMID:27366326

  12. Macrophage response to bacteria: induction of marked secretory and cellular activities by lipoteichoic acids.

    PubMed Central

    Keller, R; Fischer, W; Keist, R; Bassetti, S

    1992-01-01

    Lipoteichoic acids (LTAs) from various bacterial species, including Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Enterococcus faecalis, and Listeria monocytogenes, were examined for the ability to induce secretory and cellular responses in a pure population of bone marrow-derived mononuclear phagocytes. Some of the highly purified LTAs, in particular LTAs from Bacillus subtilis, S. pyogenes, E. faecalis, and Enterococcus hirae, were able to affect each of the macrophage parameters measured, i.e., reductive capacity, secretion of tumor necrosis factor and nitrite, and tumoricidal activity. As after stimulation with whole organisms or other bacterial products, secretion of tumor necrosis factor induced by these LTAs reached its maximum within the first few hours of the interaction, while secretion of nitrite and tumoricidal activity required 24 to 36 h for full expression. Other purified LTAs, i.e., LTAs from Streptococcus sanguis, S. pneumoniae, and L. monocytogenes, as well as lipomannan from Micrococcus luteus affected only some of these parameters, while native LTA from S. aureus was inactive. There was no obvious correlation between biological activity and chain length, kind of glycosyl substituents, glycolipid structures, or fatty acid composition of LTAs. Deacylation of LTAs resulted in a complete loss of activity, and deacylated LTAs did not impair the activity of their acylated counterparts, suggesting that acyl chains may be essential for binding of LTA to the cell surface. The results demonstrate that some LTA species are potent inducers of macrophage secretory and cellular activities. PMID:1500175

  13. Optimization of Acid Black 172 decolorization by electrocoagulation using response surface methodology

    PubMed Central

    2012-01-01

    This paper utilizes a statistical approach, the response surface optimization methodology, to determine the optimum conditions for the Acid Black 172 dye removal efficiency from aqueous solution by electrocoagulation. The experimental parameters investigated were initial pH: 4–10; initial dye concentration: 0–600 mg/L; applied current: 0.5-3.5 A and reaction time: 3–15 min. These parameters were changed at five levels according to the central composite design to evaluate their effects on decolorization through analysis of variance. High R2 value of 94.48% shows a high correlation between the experimental and predicted values and expresses that the second-order regression model is acceptable for Acid Black 172 dye removal efficiency. It was also found that some interactions and squares influenced the electrocoagulation performance as well as the selected parameters. Optimum dye removal efficiency of 90.4% was observed experimentally at initial pH of 7, initial dye concentration of 300 mg/L, applied current of 2 A and reaction time of 9.16 min, which is close to model predicted (90%) result. PMID:23369574

  14. Global Transcriptome and Mutagenic Analyses of the Acid Tolerance Response of Salmonella enterica Serovar Typhimurium

    PubMed Central

    Ryan, Daniel; Pati, Niladri Bhusan; Ojha, Urmesh K.; Padhi, Chandrashekhar; Ray, Shilpa; Jaiswal, Sangeeta; Singh, Gajinder P.; Mannala, Gopala K.; Schultze, Tilman; Chakraborty, Trinad

    2015-01-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the leading causative agents of food-borne bacterial gastroenteritis. Swift invasion through the intestinal tract and successful establishment in systemic organs are associated with the adaptability of S. Typhimurium to different stress environments. Low-pH stress serves as one of the first lines of defense in mammalian hosts, which S. Typhimurium must efficiently overcome to establish an infection. Therefore, a better understanding of the molecular mechanisms underlying the adaptability of S. Typhimurium to acid stress is highly relevant. In this study, we have performed a transcriptome analysis of S. Typhimurium under the acid tolerance response (ATR) and found a large number of genes (∼47%) to be differentially expressed (more than 1.5-fold or less than −1.5-fold; P < 0.01). Functional annotation revealed differentially expressed genes to be associated with regulation, metabolism, transport and binding, pathogenesis, and motility. Additionally, our knockout analysis of a subset of differentially regulated genes facilitated the identification of proteins that contribute to S. Typhimurium ATR and virulence. Mutants lacking genes encoding the K+ binding and transport protein KdpA, hypothetical protein YciG, the flagellar hook cap protein FlgD, and the nitrate reductase subunit NarZ were significantly deficient in their ATRs and displayed varied in vitro virulence characteristics. This study offers greater insight into the transcriptome changes of S. Typhimurium under the ATR and provides a framework for further research on the subject. PMID:26386064

  15. MALDI-TOF mass spectrometry for quantitative gene expression analysis of acid responses in Staphylococcus aureus.

    PubMed

    Rode, Tone Mari; Berget, Ingunn; Langsrud, Solveig; Møretrø, Trond; Holck, Askild

    2009-07-01

    Microorganisms are constantly exposed to new and altered growth conditions, and respond by changing gene expression patterns. Several methods for studying gene expression exist. During the last decade, the analysis of microarrays has been one of the most common approaches applied for large scale gene expression studies. A relatively new method for gene expression analysis is MassARRAY, which combines real competitive-PCR and MALDI-TOF (matrix-assisted laser desorption/ionization time-of-flight) mass spectrometry. In contrast to microarray methods, MassARRAY technology is suitable for analysing a larger number of samples, though for a smaller set of genes. In this study we compare the results from MassARRAY with microarrays on gene expression responses of Staphylococcus aureus exposed to acid stress at pH 4.5. RNA isolated from the same stress experiments was analysed using both the MassARRAY and the microarray methods. The MassARRAY and microarray methods showed good correlation. Both MassARRAY and microarray estimated somewhat lower fold changes compared with quantitative real-time PCR (qRT-PCR). The results confirmed the up-regulation of the urease genes in acidic environments, and also indicated the importance of metal ion regulation. This study shows that the MassARRAY technology is suitable for gene expression analysis in prokaryotes, and has advantages when a set of genes is being analysed for an organism exposed to many different environmental conditions. PMID:19445975

  16. Comparative responses of freshwater organisms to exposures of a commercial naphthenic acid.

    PubMed

    Kinley, Ciera M; McQueen, Andrew D; Rodgers, John H

    2016-06-01

    Comparative toxicity studies using unconfounded exposures can prioritize the selection of sensitive sentinel test species and refine methods for evaluating ecological risks of complex mixtures like naphthenic acids (NAs), a group of organic acids associated with crude oils and energy-derived waters that have been a source of aquatic toxicity. The objectives of this study were to compare responses of freshwater aquatic organisms (vertebrate, invertebrates, and a macrophyte; in terms of acute toxicity) to Fluka commercial NAs and to compare measured toxicity data with peer-reviewed toxicity data for other commercial NA sources and energy-derived NA sources. Exposures were confirmed using high performance liquid chromatography. Responses (7-d LC50s/EC50) ranged from 1.9 mg L(-1) for Pimephales promelas to 56.2 mg L(-1) for Typha latifolia. Following P. promelas in order of decreasing sensitivity were Ceriodaphnia dubia (7-d LC50 = 2.8 mg L(-1)), Hyalella azteca (7-d LC50 = 4.1 mg L(-1)), Chironomus dilutus (7-d LC50 = 6.5 mg L(-1)), and T. latifolia (7-d EC50 = 56.2 mg L(-1)), indicating that in terms of sensitivities, fish > invertebrates > plant for Fluka NAs in this study. Factors that affect exposures and measurements of exposures differ among commercial and energy-derived NAs and constrain comparisons. Despite differences in exposures, fish and invertebrates were relatively sensitive to both commercial and energy-derived NA sources (based on laboratory measurements and peer-reviewed data) and could be appropriate sentinel species for risk evaluations. PMID:27016812

  17. Stress response of some lactic acid bacteria isolated from Romanian artisan dairy products.

    PubMed

    Zamfir, Medana; Grosu-Tudor, Silvia-Simona

    2014-02-01

    Understanding the mechanisms of stress response and adaptation to stress in the case of lactic acid bacteria (LAB), especially in the case of strains with functional properties, is very important when such strains are potential candidates for starter cultures or probiotics. In this context, our study shows the response of some LAB [four exopolysaccharide (EPS)-producing strains and one strain with potential probiotic effect] to the stresses induced by low and high incubation temperatures, acidity, NaCl, and bile salts, often encountered during the technological processes in food or during the passage through the human gastro-intestinal tract. The strains were able to grow at temperatures up to 40 °C (the mesophilic strains) and 47 °C (the thermophilic strain), in medium with an initial pH of at least 4.0 (Lactobacillus acidophilus IBB801), or in the presence of NaCl up to 10% (Weissella confusa/cibaria 38.2), or bile salts up to 0.2% (L. acidophilus IBB801). The protein and isoenzyme patterns of the strains subjected to various stress conditions presented several differences compared with the control patterns, among which the overexpression of some proteins of about 50-60 kDa, differences in the bands intensity in the case of the intracellular enzymes, or the complete loss of some of these bands. The best survival to low pH values and high temperatures was observed for strain L. acidophilus IBB801, the candidate probiotic strain. The EPS production of the four tested strains was, in general, directly related to the growth, the highest yields being obtained when strains were incubated at 24 °C. PMID:23933743

  18. Activation of Nrf2-mediated oxidative stress response in macrophages by hypochlorous acid

    SciTech Connect

    Pi Jingbo Zhang Qiang; Woods, Courtney G.; Wong, Victoria; Collins, Sheila; Andersen, Melvin E.

    2008-02-01

    Hypochlorous acid (HOCl), a potent oxidant generated when chlorine gas reacts with water, is important in the pathogenesis of many disorders. Transcription factor Nrf2-mediated antioxidant response represents a critical cellular defense mechanism that serves to maintain intracellular redox homeostasis and limit oxidative damage. In the present study, the effect of HOCl on Nrf2 activation was investigated in macrophages, one of the target cells of chlorine gas exposure. Exposure of RAW 264.7 macrophages to HOCl resulted in increased protein levels of Nrf2 in nuclear extractions, as well as a time- and dose-dependent increase in the expression of Nrf2 target genes, including heme oxygenase-1, NAD(P)H:quinone oxidoreductase 1 (NQO-1), glutamate cysteine ligase catalytic subunit (GCLC), and glutathione synthetase (GS). Additionally, intracellular glutathione (GSH), which is the prime scavenger for HOCl in cells, decreased within the first hour of HOCl exposure. The decline was followed by a GSH rebound that surpassed the initial basal levels by up to 4-fold. This reversal in GSH levels closely correlated with the gene expression profile of GCLC and GS. To study the mechanisms of Nrf2 activation in response to HOCl exposure, we examined the effects of several antioxidants on Nrf2-mediated response. Pretreatment with cell-permeable catalase, N-acetyl-L-cysteine or GSH-monoethyl ester markedly reduced expression of NQO-1 and GCLC under HOCl challenge conditions, suggesting intracellular ROS-scavenging capacity affects HOCl-induced Nrf2 activation. Importantly, pre-activation of Nrf2 with low concentrations of pro-oxidants protected the cells against HOCl-induced cell damage. Taken together, we provide direct evidence that HOCl activates Nrf2-mediated antioxidant response, which protects cells from oxidative damage.

  19. Understanding and identifying amino acid repeats.

    PubMed

    Luo, Hong; Nijveen, Harm

    2014-07-01

    Amino acid repeats (AARs) are abundant in protein sequences. They have particular roles in protein function and evolution. Simple repeat patterns generated by DNA slippage tend to introduce length variations and point mutations in repeat regions. Loss of normal and gain of abnormal function owing to their variable length are potential risks leading to diseases. Repeats with complex patterns mostly refer to the functional domain repeats, such as the well-known leucine-rich repeat and WD repeat, which are frequently involved in protein–protein interaction. They are mainly derived from internal gene duplication events and stabilized by ‘gate-keeper’ residues, which play crucial roles in preventing inter-domain aggregation. AARs are widely distributed in different proteomes across a variety of taxonomic ranges, and especially abundant in eukaryotic proteins. However, their specific evolutionary and functional scenarios are still poorly understood. Identifying AARs in protein sequences is the first step for the further investigation of their biological function and evolutionary mechanism. In principle, this is an NP-hard problem, as most of the repeat fragments are shaped by a series of sophisticated evolutionary events and become latent periodical patterns. It is not possible to define a uniform criterion for detecting and verifying various repeat patterns. Instead, different algorithms based on different strategies have been developed to cope with different repeat patterns. In this review, we attempt to describe the amino acid repeat-detection algorithms currently available and compare their strategies based on an in-depth analysis of the biological significance of protein repeats. PMID:23418055

  20. Quantitative assessment of alkali-reactive aggregate mineral content through XRD using polished sections as a supplementary tool to RILEM AAR-1 (petrographic method)

    SciTech Connect

    Castro, Nelia; Sorensen, Bjorn E.; Broekmans, Maarten A.T.M.

    2012-11-15

    The mineral content of 5 aggregate samples from 4 different countries, including reactive and non-reactive aggregate types, was assessed quantitatively by X-ray diffraction (XRD) using polished sections. Additionally, electron probe microanalyzer (EPMA) mapping and cathodoluminescence (CL) were used to characterize the opal-CT identified in one of the aggregate samples. Critical review of results from polished sections against traditionally powdered specimen has demonstrated that for fine-grained rocks without preferred orientation the assessment of mineral content by XRD using polished sections may represent an advantage over traditional powder specimens. Comparison of data on mineral content and silica speciation with expansion data from PARTNER project confirmed that the presence of opal-CT plays an important role in the reactivity of one of the studied aggregates. Used as a complementary tool to RILEM AAR-1, the methodology suggested in this paper has the potential to improve the strength of the petrographic method.

  1. Modifications in membrane fatty acid composition of Salmonella typhimurium in response to growth conditions and their effect on heat resistance.

    PubMed

    Alvarez-Ordóñez, Avelino; Fernández, Ana; López, Mercedes; Arenas, Ricardo; Bernardo, Ana

    2008-04-30

    The effects of growth temperature (in the range 10-45 degrees C) and acidification up to pH 4.5 of the culture medium (Brain Heart Infusion, BHI) with different organic acids (acetic, citric and lactic) and hydrochloric acid on membrane fatty acid composition and heat resistance of Salmonella typhimurium CECT 443 were studied. The heat resistance was maximal in cells grown at 45 degrees C (cells grown in non-acidified BHI showed a D58-value of 0.90 min) and decreased with decreasing growth temperature up to 10 degrees C (D58-value of 0.09 min). The growth of cells in acidified media caused an increase in their heat resistance. In general, acid adapted cells showed D-values of between 1.5 and 2 times higher than the corresponding for non-acid adapted control cells. This cross-protection response, which has important implications in food processing, was not dependent on the pH value and the acid used to acidify the growth medium. A membrane adaptation corresponding to an increase in the unsaturated to saturated fatty acids ratio (UFA/SFA) and membrane fluidity was observed at low growth temperature. Moreover, the acidification of the growth medium caused a decrease in UFA/SFA ratio and in the C18:1 relative concentration, and an increase in cyclopropane fatty acids (CFA) content mainly due to the increase in cyc19 relative concentration. Thus, acid adapted cells showed CFA levels 1.5 times higher than non-acid adapted control cells. A significant proportion of unsaturated fatty acids were converted to their cyclopropane derivatives during acid adaptation. These changes in membrane fatty acid composition result in cells with decreased membrane fluidity. A clear relation between membrane fatty acid composition and heat resistance was observed. In general, D-values were maximum for cells with low UFA/SFA ratio, and, consequently, with low membrane fluidity. Moreover, CFA formation played a major role in protecting acid adapted cells from heat inactivation. However

  2. Theoretical study of the NLO responses of some natural and unnatural amino acids used as probe molecules.

    PubMed

    Derrar, S N; Sekkal-Rahal, M; Derreumaux, P; Springborg, M

    2014-08-01

    The first hyperpolarizabilities β of the natural aromatic amino acids tryptophan and tyrosine have been investigated using several methods and basis sets. Some of the theoretical results obtained were compared to the only experimental hyper-Rayleigh scattering data available. The sensitivity of tryptophan to its local environment was analyzed by constructing two-dimensional potential energy plots around the dipeptide tryptophan-lysine. Static hyperpolarizabilities β(0) of the found minima were calculated by a second-order Møller-Plesset (MP2) method in combination with the 6-31+G(d) basis set. Moreover, the efficiency of tryptophan and those of a series of unnatural amino acids as endogenous probe molecules were tested by calculating the nonlinear responses of some peptides. Impressive results were obtained for the amino acid ALADAN, which shows significantly improved nonlinear performance compared to other amino acids with weak nonlinear responses. PMID:25092242

  3. Diagnostic Accuracy of APRI, AAR, FIB-4, FI, and King Scores for Diagnosis of Esophageal Varices in Liver Cirrhosis: A Retrospective Study.

    PubMed

    Deng, Han; Qi, Xingshun; Peng, Ying; Li, Jing; Li, Hongyu; Zhang, Yongguo; Liu, Xu; Sun, Xiaolin; Guo, Xiaozhong

    2015-01-01

    BACKGROUND Aspartate aminotransferase-to-platelet ratio index (APRI), aspartate aminotransferase-to-alanine aminotransferase ratio (AAR), FIB-4, fibrosis index (FI), and King scores might be alternatives to the use of upper gastrointestinal endoscopy for the diagnosis of esophageal varices (EVs) in liver cirrhosis. This study aimed to evaluate their diagnostic accuracy in predicting the presence and severity of EVs in liver cirrhosis. MATERIAL AND METHODS All patients who were consecutively admitted to our hospital and underwent upper gastrointestinal endoscopy between January 2012 and June 2014 were eligible for this retrospective study. Areas under curve (AUCs) were calculated. Subgroup analyses were performed according to the history of upper gastrointestinal bleeding (UGIB) and splenectomy. RESULTS A total of 650 patients with liver cirrhosis were included, and 81.4% of them had moderate-severe EVs. In the overall analysis, the AUCs of these non-invasive scores for predicting moderate-severe EVs and presence of any EVs were 0.506-0.6 and 0.539-0.612, respectively. In the subgroup analysis of patients without UGIB, their AUCs for predicting moderate-severe varices and presence of any EVs were 0.601-0.664 and 0.596-0.662, respectively. In the subgroup analysis of patients without UGIB or splenectomy, their AUCs for predicting moderate-severe varices and presence of any EVs were 0.627-0.69 and 0.607-0.692, respectively. CONCLUSIONS APRI, AAR, FIB-4, FI, and King scores had modest diagnostic accuracy of EVs in liver cirrhosis. They might not be able to replace the utility of upper gastrointestinal endoscopy for the diagnosis of EVs in liver cirrhosis. PMID:26687574

  4. The ObgE/CgtA GTPase influences the stringent response to amino acid starvation in Escherichia coli.

    PubMed

    Persky, Nicole S; Ferullo, Daniel J; Cooper, Deani L; Moore, Hayley R; Lovett, Susan T

    2009-07-01

    The stringent response is important for bacterial survival under stressful conditions, such as amino acid starvation, and is characterized by the accumulation of ppGpp and pppGpp. ObgE (CgtA, YhbZ) is an essential conserved GTPase in Escherichia coli and several observations have implicated the protein in the control of the stringent response. However, consequences of the protein on specific responses to amino acid starvation have not been noted. We show that ObgE binds to ppGpp with biologically relevant affinity in vitro, implicating ppGpp as an in vivo ligand of ObgE. ObgE mutants increase the ratio of pppGpp to ppGpp within the cell during the stringent response. These changes are correlated with a delayed inhibition of DNA replication by the stringent response, delayed resumption of DNA replication after release, as well as a decreased survival after amino acid deprivation. With these data, we place ObgE as an active effector of the response to amino acid starvation in vivo. Our data correlate the pppGpp/ppGpp ratio with DNA replication control under bacterial starvation conditions, suggesting a possible role for the relative balance of these two nucleotides. PMID:19555460

  5. Formic and Acetic Acids in Degradation Products of Plant Volatiles Elicit Olfactory and Behavioral Responses from an Insect Vector.

    PubMed

    George, Justin; Robbins, Paul S; Alessandro, Rocco T; Stelinski, Lukasz L; Lapointe, Stephen L

    2016-05-01

    Volatile phytochemicals play a role in orientation by phytophagous insects. We studied antennal and behavioral responses of the Asian citrus psyllid, Diaphorina citri, vector of the citrus greening disease pathogen. Little or no response to citrus leaf volatiles was detected by electroantennography. Glass cartridges prepared with β-ocimene or citral produced no response initially but became stimulatory after several days. Both compounds degraded completely in air to a number of smaller molecules. Two peaks elicited large antennal responses and were identified as acetic and formic acids. Probing by D. citri of a wax substrate containing odorants was significantly increased by a blend of formic and acetic acids compared with either compound separately or blends containing β-ocimene and/or citral. Response surface modeling based on a 4-component mixture design and a 2-component mixture-amount design predicted an optimal probing response on wax substrate containing a blend of formic and acetic acids. Our study suggests that formic and acetic acids play a role in host selection by D. citri and perhaps by phytophagous insects in general even when parent compounds from which they are derived are not active. These results have implications for the investigation of arthropod olfaction and may lead to elaboration of attract-and-kill formulations to reduce nontarget effects of chemical control in agriculture. PMID:26857741

  6. A1/A2-Diamino-Substituted Pillar[5]arene-Based Acid-Base-Responsive Host-Guest System.

    PubMed

    Hu, Wei-Bo; Hu, Wen-Jing; Zhao, Xiao-Li; Liu, Yahu A; Li, Jiu-Sheng; Jiang, Biao; Wen, Ke

    2016-05-01

    An acid-base-responsive supramolecular host-guest system based on a planarly chiral A1/A2-diamino-substituted pillar[5]arene (1)/imidazolium ion recognition motif was created. The pillar[4]arene[1]diaminobenzene 1 can bring an electron-deficient imidazolium cation into its cylindrically shaped cavity under neutral or basic conditions and release it under acidic conditions. PMID:27088317

  7. Dose-response of five bile acids on serum and liver bile Acid concentrations and hepatotoxicty in mice.

    PubMed

    Song, Peizhen; Zhang, Youcai; Klaassen, Curtis D

    2011-10-01

    Feeding bile acids (BAs) to rodents has been used to study BA signaling and toxicity in vivo. However, little is known about the effect of feeding BAs on the concentrations of BAs in serum and liver as well as the dose of the fed BAs that causes liver toxicity. The present study was designed to investigate the relative hepatotoxicity of individual BAs by feeding mice cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), lithocholic acid (LCA), or ursodeoxycholic acid (UDCA) at concentrations of 0.01, 0.03, 0.1, 0.3, 1.0, or 3% in their diet for 7 days. The data demonstrate that (1) the ability of the fed BAs to produce hepatotoxicity is UDCA

  8. Bile Acid Responses in Methane and Non-Methane Producers to Standard Breakfast Meals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bile acids and their conjugates are important regulators of glucose homeostasis. Previous research has revealed the ratio of cholic acid to deoxycholic acid to affect insulin resistance in humans. Bile acid de-conjugation and intestinal metabolism depend on gut microbes which may be affected by hos...

  9. Acid resistance and response to pH-induced stress in two Lactobacillus plantarum strains with probiotic potential.

    PubMed

    Šeme, H; Gjuračić, K; Kos, B; Fujs, Š; Štempelj, M; Petković, H; Šušković, J; Bogovič Matijašić, B; Kosec, G

    2015-01-01

    Two new Lactobacillus plantarum strains, KR6-DSM 28780 and M5 isolated from sour turnip and traditional dried fresh cheese, respectively, were evaluated for species identity, antibiotic susceptibility, resistance to gastrointestinal conditions and adaptive response to low pH. Resistance mechanisms involved in the adaptation to acid-induced stress in these two strains were investigated by quantitative PCR of the atpA, cfa1, mleS and hisD genes. In addition to absence of antibiotic resistance, the two L. plantarum strains showed excellent survival rates at pH values as low as 2.4. Adaptive response to low pH was clearly observed in both strains; strain KR6 was superior to M5, as demonstrated by its ability to survive during 3 h incubation at pH 2.0 upon adaptation to moderately acidic conditions. In contrast, acid adaptation did not significantly affect the survival rate during simulated passage through the gastrointestinal tract. In both strains, induction of histidine biosynthesis (hisD) was upregulated during the acid adaptation response. In addition, significant upregulation of the cfa1 gene, involved in modulation of membrane fatty acid composition, was observed during the adaptation phase in strain KR6 but not in strain M5. Cells adapted to moderately acidic conditions also showed a significantly increased viability after the lyophilisation procedure, a cross-protection phenomenon providing additional advantage in probiotic application. PMID:25380802

  10. Optimizing ultrasonic ellagic acid extraction conditions from infructescence of Platycarya strobilacea using response surface methodology.

    PubMed

    Zhang, Liang-Liang; Xu, Man; Wang, Yong-Mei; Wu, Dong-Mei; Chen, Jia-Hong

    2010-11-01

    The infructescence of Platycarya strobilacea is a rich source of ellagic acid (EA) which has shown antioxidant, anticancer and antimutagen properties. Response surface methodology (RSM) was used to optimize the conditions for ultrasonic extraction of EA from infructescence of P. strobilacea. A central composite design (CCD) was used for experimental design and analysis of the results to obtain the optimal processing parameters. The content of EA in the extracts was determined by HPLC with UV detection. Three independent variables such as ultrasonic extraction temperature (°C), liquid:solid ratio (mL/g), and ultrasonic extraction time (min) were investigated. The experimental data obtained were fitted to a quadratic equation using multiple regression analysis and also analyzed by appropriate statistical methods. The 3-D response surface and the contour plots derived from the mathematical models were applied to determine the optimal conditions. The optimum ultrasonic extraction conditions were as follows: ultrasonic extraction temperature 70 °C, liquid:solid ratio 22.5, and ultrasonic extraction time 40 min. Under these conditions, the experimental percentage value was 1.961%, which is in close agreement with the value predicted by the model. PMID:21060299

  11. Accumulation of Amino Acids in Rhizobium sp. Strain WR1001 in Response to Sodium Chloride Salinity

    PubMed Central

    Hua, Sui-Sheng T.; Tsai, Victor Y.; Lichens, Georgia M.; Noma, Amy T.

    1982-01-01

    Rhizobium sp. strain WR1001, isolated from the Sonoran Desert by Eskew and Ting, was found to be able to grow in defined medium containing NaCl up to 500 mM, a concentration approaching that of sea water. Therefore, it is a valuable strain for studying the biochemical basis of salt tolerance. Intracellular free glutamate was found to increase rapidly in response to osmotic stress by NaCl. It accounted for 88% of the amino acid pool when the bacterium was grown in 500 mM NaCl. The role of glutamate dehydrogenase in glutamate biosynthesis was examined in several Rhizobium strains. Both NADH- and NADPH-dependent glutamate dehydrogenase activities in various Rhizobium strains were observed. The range of activity differed considerably depending on the particular strain. KCl (500 mM) did not stimulate glutamate dehydrogenase activity, as reported in a number of bacterial strains by Measures. The low activity of glutamate dehydrogenase in Rhizobium sp. strain WR1001 apparently cannot fulfill a biosynthetic function of glutamate formation in response to medium NaCl concentrations. PMID:16346049

  12. Surface properties and early murine pre-osteoblastic cell responses of phosphoric acid modified titanium surface

    PubMed Central

    Osathanon, Thanaphum; Sawangmake, Chenphop; Ruangchainicom, Nanticha; Wutikornwipak, Pavitra; Kantukiti, Panisa; Nowwarote, Nunthawan; Pavasant, Prasit

    2015-01-01

    Aims The present study investigated the surface properties and murine pre-osteoblast cell (MC3T3-E1) responses of phosphoric acid (H3PO4) treated commercially pure titanium. Methods Titanium discs were treated with various concentration of H3PO4 (5%, 10%, and 20%; v/v) at 90 °C for 30 min. Surface properties were evaluated by profilometer, contact angle meter, and scanning electron microscopy (SEM) with energy dispersive X-rays. MC3T3-E1 attachment and spreading were evaluated by SEM and phalloidin immunohistochemistry staining. Results Surface roughness and wettability were not statistically difference among all experimental and control groups. Phosphate and oxygen were detected on H3PO4 treated surfaces. At 20 min, cell attachment was significantly higher in 10% and 20% H3PO4 treated groups compared to the control. Cells exhibited orientated-cytoskeleton fibers on 20% H3PO4 modified titanium surface. Though, there was no difference in cell spreading stage among all treatment groups. Conclusion H3PO4 treatment on titanium may influence early cell response, particularly on attachment and spreading. PMID:26937362

  13. Tormentic Acid Inhibits IL-1β-Induced Inflammatory Response in Human Osteoarthritic Chondrocytes.

    PubMed

    Yang, Yang; Wang, Yawei; Wang, Yumin; Zhao, Meng; Jia, Haobo; Li, Bing; Xing, Dan

    2016-06-01

    The pro-inflammatory cytokine interleukin-1beta (IL-1β) plays critical roles in pathogenesis of osteoarthritis (OA). Tormentic acid (TA), a triterpene isolated from Rosa rugosa, has anti-inflammatory activity. However, the anti-inflammatory effect of TA on OA is still unclear. So, in the present study, we examined the effect of TA on IL-1β-induced inflammatory response in primary human OA chondrocytes. Our results demonstrated that TA significantly decreased the IL-1β-stimulated expression of matrix metalloproteinase-3 (MMP-3) and MMP-13. It also inhibited the IL-1β-induced expression of inducible nitric oxide (NO) synthase (iNOS) and cyclooxygenase-2 (COX-2), as well as the production of NO and prostaglandin E2 (PGE2) in human OA chondrocytes. Furthermore, TA greatly inhibited the IL-1β-induced NF-κB activation. In conclusion, this study is the first to demonstrate the anti-inflammatory activity of TA in human OA chondrocytes. TA significantly inhibits the IL-1β-induced inflammatory response by suppressing the NF-κB signaling pathway. Thus, TA may be a potential agent in the treatment of OA. PMID:27102898

  14. Boronic Acid-Appended Molecular Glues for ATP-Responsive Activity Modulation of Enzymes.

    PubMed

    Okuro, Kou; Sasaki, Mizuki; Aida, Takuzo

    2016-05-01

    Water-soluble linear polymers GumBAn (m/n = 18/6, 12/12, and 6/18) with multiple guanidinium ion (Gu(+)) and boronic acid (BA) pendants in their side chains were synthesized as ATP-responsive modulators for enzyme activity. GumBAn polymers strongly bind to the phosphate ion (PO4(-)) and 1,2-diol units of ATP via the Gu(+) and BA pendants, respectively. As only the Gu(+) pendants can be used for proteins, GumBAn is able to modulate the activity of enzymes in response to ATP. As a proof-of-concept study, we demonstrated that trypsin (Trp) can be deactivated by hybridization with GumBAn. However, upon addition of ATP, Trp was liberated to retrieve its hydrolytic activity due to a higher preference of GumBAn toward ATP than Trp. This event occurred in a much lower range of [ATP] than reported examples. Under cellular conditions, the hydrolytic activity of Trp was likewise modulated. PMID:27087468

  15. Stomatal response to abscisic Acid is a function of current plant water status.

    PubMed

    Tardieu, F; Davies, W J

    1992-02-01

    We investigated, under laboratory and field conditions, the possibility that increasing abscisic acid (ABA) concentrations and decreasing water potentials can interact in their effects on stomata. One experiment was carried out with epidermal pieces of Commelina communis incubated in media with a variety of ABA and polyethylene glycol concentrations. In the media without ABA, incubation in solutions with water potentials between -0.3 and -1.5 megapascals had no significant effect on stomatal aperture. Conversely, the sensitivity of stomatal aperture to ABA was trebled in solutions at -1.5 megapascals compared with sensitivity at -0.3 megapascals. The effect of the change in sensitivity was more important than the absolute effect of ABA at the highest water potential. In a field experiment, sensitivity of maize stomatal conductance to the concentration of ABA in the xylem sap varied strongly with the time of the day. We consider that the most likely explanation for this is the influence of a change in leaf or epidermal water potential that accompanies an increase in irradiance and saturation deficit as the day progresses. These observations suggest that epidermal water relations may act as a modulator of the responses of stomata to ABA. We argue that such changes must be taken into account in studies or modeling of plant responses to drought stress. PMID:16668674

  16. Lysophosphatidic Acid (LPA) Receptor 5 Inhibits B Cell Antigen Receptor Signaling and Antibody Response1

    PubMed Central

    Shotts, Kristin; Donovan, Erin E.; Strauch, Pamela; Pujanauski, Lindsey M.; Victorino, Francisco; Al-Shami, Amin; Fujiwara, Yuko; Tigyi, Gabor; Oravecz, Tamas; Pelanda, Roberta; Torres, Raul M.

    2014-01-01

    Lysophospholipids have emerged as biologically important chemoattractants capable of directing lymphocyte development, trafficking and localization. Lysophosphatidic acid (LPA) is a major lysophospholipid found systemically and whose levels are elevated in certain pathological settings such as cancer and infections. Here, we demonstrate that BCR signal transduction by mature murine B cells is inhibited upon LPA engagement of the LPA5 (GPR92) receptor via a Gα12/13 – Arhgef1 pathway. The inhibition of BCR signaling by LPA5 manifests by impaired intracellular calcium store release and most likely by interfering with inositol 1,4,5-trisphosphate receptor activity. We further show that LPA5 also limits antigen-specific induction of CD69 and CD86 expression and that LPA5-deficient B cells display enhanced antibody responses. Thus, these data show that LPA5 negatively regulates BCR signaling, B cell activation and immune response. Our findings extend the influence of lysophospholipids on immune function and suggest that alterations in LPA levels likely influence adaptive humoral immunity. PMID:24890721

  17. Maternal fatty acid desaturase genotype correlates with infant immune responses at 6 months.

    PubMed

    Muc, Magdalena; Kreiner-Møller, Eskil; Larsen, Jeppe M; Birch, Sune; Brix, Susanne; Bisgaard, Hans; Lauritzen, Lotte

    2015-09-28

    Breast milk long-chain PUFA (LCPUFA) have been associated with changes in early life immune responses and may modulate T-cell function in infancy. We studied the effect of maternal fatty acid desaturase (FADS) genotype and breast milk LCPUFA levels on infants' blood T-cell profiles and ex vivo-produced cytokines after anti-CD3/CD28 stimulation of peripheral blood mononuclear cells in 6-month-old infants from the Copenhagen Prospective Study of Asthma in Childhood birth cohort. LCPUFA concentrations of breast milk were assessed at 4 weeks of age, and FADS SNP were determined in both mothers and infants (n 109). In general, breast milk arachidonic acid (AA) levels were inversely correlated with the production of IL-10 (r -0.25; P=0.004), IL-17 (r -0.24; P=0.005), IL-5 (r -0.21; P=0.014) and IL-13 (r -0.17; P=0.047), whereas EPA was positively correlated with the counts of blood regulatory T-cells and cytotoxic T-cells and decreased T-helper cell counts. The minor FADS alleles were associated with lower breast milk AA and EPA, and infants of mothers carrying the minor allele of FADS SNP rs174556 had higher production of IL-10 (r -0.23; P=0.018), IL-17 (r -0.25; P=0.009) and IL-5 (r -0.21; P=0.038) from ex vivo-activated immune cells. We observed no association between T-cell distribution and maternal or infant FADS gene variants. We conclude that increased maternal LCPUFA synthesis and breast milk AA are associated with decreased levels of IL-5, IL-13 (type-2 related), IL-17 (type-17 related) and IL-10 (regulatory immune responses), but not with interferon-γ and TNF-α, which could be due to an effect of the maternal FADS variants on the offspring immune response transferred via breast milk LCPUFA. PMID:26283408

  18. Effect of Pre-Stressing on the Acid-Stress Response in Bifidobacterium Revealed Using Proteomic and Physiological Approaches.

    PubMed

    Jin, Junhua; Qin, Qian; Guo, Huiyuan; Liu, Songling; Ge, Shaoyang; Zhang, Hongxing; Cui, Jianyun; Ren, Fazheng

    2015-01-01

    Weak acid resistance limits the application of Bifidobacteria as a probiotic in food. The acid tolerance response (ATR), caused by pre-stressing cells at a sublethal pH, could improve the acid resistance of Bifidobacteria to subsequent acid stress. In this study, we used Bifidobacterium longum sub. longum BBMN68 to investigate the effect of the ATR on the acid stress response (ASR), and compared the difference between the ATR and the ASR by analyzing the two-dimensional-PAGE protein profiles and performing physiological tests. The results revealed that a greater abundance of proteins involved in carbohydrate metabolism and protein protection was present after the ASR than after the ATR in Bifidobacterium. Pre-stressing cells increased the abundance of proteins involved in energy production, amino acid metabolism, and peptidoglycan synthesis during the ASR of Bifidobacterium. Moreover, after the ASR, the content of ATP, NH3, thiols, and peptidoglycan, the activity of H+-ATPase, and the maintenance of the intracellular pH in the pre-stressed Bifidobacterium cells was significantly higher than in the uninduced cells. These results provide the first explanation as to why the resistance of Bifidobacterium to acid stress improved after pre-stressing. PMID:25689631

  19. Adipocyte amino acid sensing controls adult germline stem cell number via the amino acid response pathway and independently of Target of Rapamycin signaling in Drosophila.

    PubMed

    Armstrong, Alissa R; Laws, Kaitlin M; Drummond-Barbosa, Daniela

    2014-12-01

    How adipocytes contribute to the physiological control of stem cells is a critical question towards understanding the link between obesity and multiple diseases, including cancers. Previous studies have revealed that adult stem cells are influenced by whole-body physiology through multiple diet-dependent factors. For example, nutrient-dependent pathways acting within the Drosophila ovary control the number and proliferation of germline stem cells (GSCs). The potential role of nutrient sensing by adipocytes in modulating stem cells in other organs, however, remains largely unexplored. Here, we report that amino acid sensing by adult adipocytes specifically modulates the maintenance of GSCs through a Target of Rapamycin-independent mechanism. Instead, reduced amino acid levels and the consequent increase in uncoupled tRNAs trigger activation of the GCN2-dependent amino acid response pathway within adipocytes, causing increased rates of GSC loss. These studies reveal a new step in adipocyte-stem cell crosstalk. PMID:25359724

  20. Adipocyte amino acid sensing controls adult germline stem cell number via the amino acid response pathway and independently of Target of Rapamycin signaling in Drosophila

    PubMed Central

    Armstrong, Alissa R.; Laws, Kaitlin M.; Drummond-Barbosa, Daniela

    2014-01-01

    How adipocytes contribute to the physiological control of stem cells is a critical question towards understanding the link between obesity and multiple diseases, including cancers. Previous studies have revealed that adult stem cells are influenced by whole-body physiology through multiple diet-dependent factors. For example, nutrient-dependent pathways acting within the Drosophila ovary control the number and proliferation of germline stem cells (GSCs). The potential role of nutrient sensing by adipocytes in modulating stem cells in other organs, however, remains largely unexplored. Here, we report that amino acid sensing by adult adipocytes specifically modulates the maintenance of GSCs through a Target of Rapamycin-independent mechanism. Instead, reduced amino acid levels and the consequent increase in uncoupled tRNAs trigger activation of the GCN2-dependent amino acid response pathway within adipocytes, causing increased rates of GSC loss. These studies reveal a new step in adipocyte-stem cell crosstalk. PMID:25359724

  1. Oleanolic Acid Controls Allergic and Inflammatory Responses in Experimental Allergic Conjunctivitis

    PubMed Central

    Martínez-García, Carmen; Martín, Rubén; Gallego-Muñoz, Patricia; Hernández, Marita; Nieto, María L.

    2014-01-01

    Pollen is the most common aeroallergen to cause seasonal conjunctivitis. The result of allergen exposure is a strong Th2-mediated response along with conjunctival mast cell degranulation and eosinophilic infiltration. Oleanolic acid (OA) is natural a triterpene that displays strong anti-inflammatory and immunomodulatory properties being an active anti-allergic molecule on hypersensitivity reaction models. However, its effect on inflammatory ocular disorders including conjunctivits, has not yet been addressed. Hence, using a Ragweed pollen (RWP)-specific allergic conjunctivitis (EAC) mouse model we study here whether OA could modify responses associated to allergic processes. We found that OA treatment restricted mast cell degranulation and infiltration of eosinophils in conjunctival tissue and decreased allergen-specific Igs levels in EAC mice. Th2-type cytokines, secreted phospholipase A2 type-IIA (sPLA2-IIA), and chemokines levels were also significantly diminished in the conjunctiva and serum of OA-treated EAC mice. Moreover, OA treatment also suppressed RWP-specific T-cell proliferation. In vitro studies, on relevant cells of the allergic process, revealed that OA reduced the proliferative and migratory response, as well as the synthesis of proinflammatory mediators on EoL-1 eosinophils and RBL-2H3 mast cells exposed to allergic and/or crucial inflammatory stimuli such as RWP, sPLA2-IIA or eotaxin. Taken together, these findings demonstrate the beneficial activity of OA in ocular allergic processes and may provide a new intervention strategy and potential therapy for allergic diseases. PMID:24699261

  2. Life in heaps: a review of microbial responses to variable acidity in sulfide mineral bioleaching heaps for metal extraction.

    PubMed

    Shiers, D W; Collinson, D M; Watling, H R

    2016-09-01

    Industrial heap leaching of low grade mineral sulfide ores is catalysed by the use of acidophilic microorganisms. These microorganisms obtain energy for growth from the oxidation of reduced inorganic or organic compounds, including soluble ferrous ion, reduced inorganic sulfur compounds (RISC) and acid-stable organic compounds. By-products of these oxidative processes, such as soluble ferric ion and sulfuric acid create favourable chemical conditions for leaching. This review is focused on the behaviour of common bioleaching microorganisms, their responses to changing pH in an industrial setting, and how both changes and microbial responses can impact the micro and macro environment. PMID:27283362

  3. The salt stress-induced LPA response in Chlamydomonas is produced via PLA2 hydrolysis of DGK-generated phosphatidic acid[S

    PubMed Central

    Arisz, Steven A.; Munnik, Teun

    2011-01-01

    The unicellular green alga Chlamydomonas has frequently been used as a eukaryotic model system to study intracellular phospholipid signaling pathways in response to environmental stresses. Earlier, we found that hypersalinity induced a rapid increase in the putative lipid second messenger, phosphatidic acid (PA), which was suggested to be generated via activation of a phospholipase D (PLD) pathway and the combined action of a phospholipase C/diacylglycerol kinase (PLC/DGK) pathway. Lysophosphatidic acid (LPA) was also increased and was suggested to reflect a phospholipase A2 (PLA2) activity based on pharmacological evidence. The question of PA's and LPA's origin is, however, more complicated, especially as both function as precursors in the biosynthesis of phospho- and galactolipids. To address this complexity, a combination of fatty acid-molecular species analysis and in vivo 32P-radiolabeling was performed. Evidence is provided that LPA is formed from a distinct pool of PA characterized by a high α-linolenic acid (18:3n-3) content. This molecular species was highly enriched in the polyphosphoinositide fraction, which is the substrate for PLC to form diacylglycerol. Together with differential 32P-radiolabeling studies and earlier PLD-transphosphatidylation and PLA2-inhibitor assays, the data were consistent with the hypothesis that the salt-induced LPA response is primarily generated through PLA2-mediated hydrolysis of DGK-generated PA and that PLD or de novo synthesis [via endoplasmic reticulum - or plastid-localized routes] is not a major contributor. PMID:21900174

  4. Polyphenolic responses of grapevine berries to light, temperature, oxidative stress, abscisic acid and jasmonic acid show specific developmental-dependent degrees of metabolic resilience to perturbation.

    PubMed

    Degu, Asfaw; Ayenew, Biruk; Cramer, Grant R; Fait, Aaron

    2016-12-01

    Grape-berries are exposed to a plethora of abiotic and biotic stimuli during their development. The developmental and temporal regulation of grape berry polyphenol metabolism in response to various cues was investigated using LC-QTOF-MS based metabolite profiling. High light (2500μmolm(-2)s(-1)), high temperature (40°C), jasmonic acid (200μM), menadione (120μM) and abscisic acid (3.026mM) treatments were applied to detached berries. Greater magnitudes of metabolite fluctuations characterize the pre-veraison berries than the veraison stage in response to the treatments. Furthermore, a tighter co-response of metabolic processes was shown at veraison, likely supporting the resilience to change in response to stress. High temperature and ABA treatments led to greater magnitudes of change during the course of the experiment. The present study demonstrates the occurrence of differential patterns of metabolic responses specific to individual cues and berry developmental stage, which in the field are commonly associated and thus hardly discernable. PMID:27374601

  5. Phragmites australis response to Cu in terms of low molecular weight organic acids (LMWOAs) exudation: Influence of the physiological cycle

    NASA Astrophysics Data System (ADS)

    Rocha, A. Cristina S.; Almeida, C. Marisa R.; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

    2014-06-01

    Plant roots have the ability to produce and secrete substances, such as aliphatic low molecular weight organic acids (ALMWOAs), into the rhizosphere for several purposes, including in response to metal contamination. Despite this, little is yet known about the exudation of such substances from marsh plants roots in response to metal exposure. This work aimed at assessing the influence of the physiological cycle of marsh plants on the exudation of ALMWOAs in response to Cu contamination. In vitro experiments were carried out with Phragmites australis specimens, collected in different seasons. Plant roots were exposed to freshwater contaminated with two different Cu concentrations (67 μg/L and 6.9 mg/L), being the ALMWOAs released by the roots measured. Significant differences (both qualitative and quantitative) were observed during the Phragmites australis life cycle. At growing stage, Cu stimulated the exudation of oxalic and formic acids but no significant stimulation was observed for citric acid. At developing stage, exposure to Cu caused inhibition of oxalic acid exudation whereas citric acid liberation was stimulated but only in the media spiked with the lowest Cu concentration tested. At the decaying stage, no significant variation on oxalic acid was observed, whereas the citric and formic acids release increased as a consequence of the plant exposure to Cu. The physiological cycle of Phragmites australis, and probably also of other marsh plants, is therefore an important feature conditioning plants response to Cu contamination, in terms of ALMWOAs exudation. Hence this aspect should be considered when conducting studies on rhizodeposition involving marsh plants exposed to metals and in the event of using marsh plants for phytoremediation purposes in contaminated estuarine areas.

  6. Hexanoic acid protects tomato plants against Botrytis cinerea by priming defence responses and reducing oxidative stress.

    PubMed

    Finiti, Ivan; de la O Leyva, María; Vicedo, Begonya; Gómez-Pastor, Rocío; López-Cruz, Jaime; García-Agustín, Pilar; Real, Maria Dolores; González-Bosch, Carmen

    2014-08-01

    Treatment with the resistance priming inducer hexanoic acid (Hx) protects tomato plants from Botrytis cinerea by activating defence responses. To investigate the molecular mechanisms underlying hexanoic acid-induced resistance (Hx-IR), we compared the expression profiles of three different conditions: Botrytis-infected plants (Inf), Hx-treated plants (Hx) and Hx-treated + infected plants (Hx+Inf). The microarray analysis at 24 h post-inoculation showed that Hx and Hx+Inf plants exhibited the differential expression and priming of many Botrytis-induced genes. Interestingly, we found that the activation by Hx of other genes was not altered by the fungus at this time point. These genes may be considered to be specific targets of the Hx priming effect and may help to elucidate its mechanisms of action. It is noteworthy that, in Hx and Hx+Inf plants, there was up-regulation of proteinase inhibitor genes, DNA-binding factors, enzymes involved in plant hormone signalling and synthesis, and, remarkably, the genes involved in oxidative stress. Given the relevance of the oxidative burst occurring in plant-pathogen interactions, the effect of Hx on this process was studied in depth. We showed by specific staining that reactive oxygen species (ROS) accumulation in Hx+Inf plants was reduced and more restricted around infection sites. In addition, these plants showed higher ratios of reduced to oxidized glutathione and ascorbate, and normal levels of antioxidant activities. The results obtained indicate that Hx protects tomato plants from B. cinerea by regulating and priming Botrytis-specific and non-specific genes, preventing the harmful effects of oxidative stress produced by infection. PMID:24320938

  7. Optimization of Alkaline and Dilute Acid Pretreatment of Agave Bagasse by Response Surface Methodology.

    PubMed

    Ávila-Lara, Abimael I; Camberos-Flores, Jesus N; Mendoza-Pérez, Jorge A; Messina-Fernández, Sarah R; Saldaña-Duran, Claudia E; Jimenez-Ruiz, Edgar I; Sánchez-Herrera, Leticia M; Pérez-Pimienta, Jose A

    2015-01-01

    Utilization of lignocellulosic materials for the production of value-added chemicals or biofuels generally requires a pretreatment process to overcome the recalcitrance of the plant biomass for further enzymatic hydrolysis and fermentation stages. Two of the most employed pretreatment processes are the ones that used dilute acid (DA) and alkaline (AL) catalyst providing specific effects on the physicochemical structure of the biomass, such as high xylan and lignin removal for DA and AL, respectively. Another important effect that need to be studied is the use of a high solids pretreatment (≥15%) since offers many advantaged over lower solids loadings, including increased sugar and ethanol concentrations (in combination with a high solids saccharification), which will be reflected in lower capital costs; however, this data is currently limited. In this study, several variables, such as catalyst loading, retention time, and solids loading, were studied using response surface methodology (RSM) based on a factorial central composite design of DA and AL pretreatment on agave bagasse using a range of solids from 3 to 30% (w/w) to obtain optimal process conditions for each pretreatment. Subsequently enzymatic hydrolysis was performed using Novozymes Cellic CTec2 and HTec2 presented as total reducing sugar (TRS) yield. Pretreated biomass was characterized by wet-chemistry techniques and selected samples were analyzed by calorimetric techniques, and scanning electron/confocal fluorescent microscopy. RSM was also used to optimize the pretreatment conditions for maximum TRS yield. The optimum conditions were determined for AL pretreatment: 1.87% NaOH concentration, 50.3 min and 13.1% solids loading, whereas DA pretreatment: 2.1% acid concentration, 33.8 min and 8.5% solids loading. PMID:26442260

  8. Optimization of Alkaline and Dilute Acid Pretreatment of Agave Bagasse by Response Surface Methodology

    PubMed Central

    Ávila-Lara, Abimael I.; Camberos-Flores, Jesus N.; Mendoza-Pérez, Jorge A.; Messina-Fernández, Sarah R.; Saldaña-Duran, Claudia E.; Jimenez-Ruiz, Edgar I.; Sánchez-Herrera, Leticia M.; Pérez-Pimienta, Jose A.

    2015-01-01

    Utilization of lignocellulosic materials for the production of value-added chemicals or biofuels generally requires a pretreatment process to overcome the recalcitrance of the plant biomass for further enzymatic hydrolysis and fermentation stages. Two of the most employed pretreatment processes are the ones that used dilute acid (DA) and alkaline (AL) catalyst providing specific effects on the physicochemical structure of the biomass, such as high xylan and lignin removal for DA and AL, respectively. Another important effect that need to be studied is the use of a high solids pretreatment (≥15%) since offers many advantaged over lower solids loadings, including increased sugar and ethanol concentrations (in combination with a high solids saccharification), which will be reflected in lower capital costs; however, this data is currently limited. In this study, several variables, such as catalyst loading, retention time, and solids loading, were studied using response surface methodology (RSM) based on a factorial central composite design of DA and AL pretreatment on agave bagasse using a range of solids from 3 to 30% (w/w) to obtain optimal process conditions for each pretreatment. Subsequently enzymatic hydrolysis was performed using Novozymes Cellic CTec2 and HTec2 presented as total reducing sugar (TRS) yield. Pretreated biomass was characterized by wet-chemistry techniques and selected samples were analyzed by calorimetric techniques, and scanning electron/confocal fluorescent microscopy. RSM was also used to optimize the pretreatment conditions for maximum TRS yield. The optimum conditions were determined for AL pretreatment: 1.87% NaOH concentration, 50.3 min and 13.1% solids loading, whereas DA pretreatment: 2.1% acid concentration, 33.8 min and 8.5% solids loading. PMID:26442260

  9. Nordihydroguaiaretic acid activates hTRPA1 and modulates behavioral responses to noxious cold in mice

    PubMed Central

    Redmond, William John; Camo, Maxime; Mitchell, Vanessa; Vaughan, Christopher Walter; Connor, Mark

    2014-01-01

    Nordihydroguaiaretic acid (NDGA) is a major biologically active component of the creosote bush, Larrea tridentate, widely used in unregulated therapies. NDGA is a lipoxygenase inhibitor while a derivative, terameprocol, has been trialed as a chemotherapeutic agent. When investigating fatty acid activation of the human transient receptor potential cation channel subfamily A, member 1 (hTRPA1), we found that NDGA activated the channel. Here we investigate the actions of NDGA and terameprocol at hTRPA1 and the consequences of this for noxious cold sensitivity in mice. hTRPA1 was stably expressed in HEK 293 cells (HEK 293-TRPA1) and channel activity examined by measuring changes in intracellular calcium ([Ca]i) using a fluorescent dye and activation of membrane currents using patch clamp electrophysiology. The effects of local NDGA and terameprocol application on acetone-induced paw flinching were examined in mice. NDGA (pEC50 of 5.4 ± 0.1, maximum change in fluorescence of 385 ± 30%) and terameprocol (pEC50 4.5 ± 0.2, maximum 550 ± 75%) increased [Ca]i in HEK 293-hTRPA1 cells. NDGA also induced an increase in membrane conductance in HEK 293-hTRPA1 cells. These effects were prevented by the TRPA1 antagonist HC-030031, and were dependent on the presence of Cys621, Cys 641, and Cys 665 in hTRPA1. Neither NDGA nor terameprocol alone produced spontaneous pain behaviors in mice after hind paw injection, but both enhanced responses to acetone. NDGA and terameprocol are efficacious activators of TRPA1. NDGA should be used with care to probe lipoxygenase involvement in nociception while TRPA1 activity should be considered when considering use of these drugs in humans. PMID:25505619

  10. Physiological and performance responses to supplementation with thiamin and pantothenic acid derivatives.

    PubMed

    Webster, M J

    1998-05-01

    The purpose of this study was to investigate the physiological and performance responses to supplementation with allithiamin and pantethine. On two separate occasions, six highly trained cyclists [maximum O2 consumption or VO2max 61.8 (2.1) ml x kg(-1) x min(-1)] performed a 50-km steady-state ride on a cycle ergometer at a workload corresponding to approximately 60% of VO2max followed by a 2000-m time trial. For 7 days prior to each ride, subjects daily ingested either a placebo (PL) or a combination of 1 g of allithiamin and 1.8 g of a 55%/45% pantethine/pantothenic acid compound (AP). Treatments were administered using a randomized, double-blind, counter-balanced design. During the 50km ride, measures of heart rate, respiratory gas exchange and ratings of perceived exertion were recorded at 5, 15, 25, 35 and 45 km. Blood samples were collected at 10, 20, 30, 40 and 50 km and analyzed for lactate, glucose and free fatty acids. Blood samples for the analysis of lactate were also collected 3 and 5 min after the completion of the 2000-m time trial. There were no significant differences in any of the measured parameters between experimental conditions. Time to complete the 2000-m time trial was also not significantly different between experimental conditions [PL 178.2 (8.4), AP 170.7 (10.2) s; P=0.58]. These results suggest that, despite the reported enhanced absorption properties, supplementation with allithiamin and pantethine does not alter exercise metabolism or exercise performance. PMID:9650731

  11. Quantitative Assessment of MRI T2 Response to Kainic Acid Neurotoxicity in Rats in vivo.

    PubMed

    Liachenko, Serguei; Ramu, Jaivijay; Konak, Tetyana; Paule, Merle G; Hanig, Joseph

    2015-07-01

    The aim of this study was to assess quantitative changes in T2 relaxation using magnetic resonance imaging approaches in rats exposed to kainic acid to assess the utility of such endpoints as biomarkers of neurotoxicity. Quantitative T2 mapping was performed in 21 rats before and 2, 24, and 48 h after a single ip injection of 10 mg/kg of kainic acid. Three methods of quantifying T2 changes were explored: (1) Thresholding: all voxels exhibiting T2 ≤ 72 ms were designated normal tissue, whereas voxels exhibiting T2 > 72 ms were designated as lesioned tissue; (2) Statistical mapping: T2 maps obtained after treatment were statistically compared with averaged "baseline" maps, voxel-by-voxel; (3) Within-subject difference from baseline: for each individual the baseline T2 map was subtracted from the T2 map obtained after treatment. Based on the follow-up histopathological response there were 9 responders, 7 nonresponders, and 5 animals were not classified due to early sacrifice at 2 h which was too soon after treatment to detect any morphological evidence. The "thresholding" method (1) detected differences between groups only at the later time point of 48 h, the "statistical mapping" approach (2) detected differences 24 and 48 h after treatment, and the "within-subject difference from baseline" method (3) detected statistically significant differences between groups at each time point (2, 24, and 48 h). T2 mapping provides an easily quantifiable biomarker and the quantification method employing the use of the same animal as its own control provides the most sensitive metrics. PMID:25904105

  12. Response surface optimization of culture medium for enhanced docosahexaenoic acid production by a Malaysian thraustochytrid

    PubMed Central

    Manikan, Vidyah; Kalil, Mohd Sahaid; Hamid, Aidil Abdul

    2015-01-01

    Docosahexaenoic acid (DHA, C22:6n-3) plays a vital role in the enhancement of human health, particularly for cognitive, neurological, and visual functions. Marine microalgae, such as members of the genus Aurantiochytrium, are rich in DHA and represent a promising source of omega-3 fatty acids. In this study, levels of glucose, yeast extract, sodium glutamate and sea salt were optimized for enhanced lipid and DHA production by a Malaysian isolate of thraustochytrid, Aurantiochytrium sp. SW1, using response surface methodology (RSM). The optimized medium contained 60 g/L glucose, 2 g/L yeast extract, 24 g/L sodium glutamate and 6 g/L sea salt. This combination produced 17.8 g/L biomass containing 53.9% lipid (9.6 g/L) which contained 44.07% DHA (4.23 g/L). The optimized medium was used in a scale-up run, where a 5 L bench-top bioreactor was employed to verify the applicability of the medium at larger scale. This produced 24.46 g/L biomass containing 38.43% lipid (9.4 g/L), of which 47.87% was DHA (4.5 g/L). The total amount of DHA produced was 25% higher than that produced in the original medium prior to optimization. This result suggests that Aurantiochytrium sp. SW1 could be developed for industrial application as a commercial DHA-producing microorganism. PMID:25721623

  13. Lipidomic profiling of Saccharomyces cerevisiae and Zygosaccharomyces bailii reveals critical changes in lipid composition in response to acetic acid stress.

    PubMed

    Lindberg, Lina; Santos, Aline Xs; Riezman, Howard; Olsson, Lisbeth; Bettiga, Maurizio

    2013-01-01

    When using microorganisms as cell factories in the production of bio-based fuels or chemicals from lignocellulosic hydrolysate, inhibitory concentrations of acetic acid, released from the biomass, reduce the production rate. The undissociated form of acetic acid enters the cell by passive diffusion across the lipid bilayer, mediating toxic effects inside the cell. In order to elucidate a possible link between lipid composition and acetic acid stress, the present study presents detailed lipidomic profiling of the major lipid species found in the plasma membrane, including glycerophospholipids, sphingolipids and sterols, in Saccharomyces cerevisiae (CEN.PK 113_7D) and Zygosaccharomyces bailii (CBS7555) cultured with acetic acid. Detailed physiological characterization of the response of the two yeasts to acetic acid has also been performed in aerobic batch cultivations using bioreactors. Physiological characterization revealed, as expected, that Z. bailii is more tolerant to acetic acid than S. cerevisiae. Z. bailii grew at acetic acid concentrations above 24 g L(-1), while limited growth of S. cerevisiae was observed after 11 h when cultured with only 12 g L(-1) acetic acid. Detailed lipidomic profiling using electrospray ionization, multiple-reaction-monitoring mass spectrometry (ESI-MRM-MS) showed remarkable changes in the glycerophospholipid composition of Z. bailii, including an increase in saturated glycerophospholipids and considerable increases in complex sphingolipids in both S. cerevisiae (IPC 6.2×, MIPC 9.1×, M(IP)2C 2.2×) and Z. bailii (IPC 4.9×, MIPC 2.7×, M(IP)2C 2.7×), when cultured with acetic acid. In addition, the basal level of complex sphingolipids was significantly higher in Z. bailii than in S. cerevisiae, further emphasizing the proposed link between lipid saturation, high sphingolipid levels and acetic acid tolerance. The results also suggest that acetic acid tolerance is associated with the ability of a given strain to generate large

  14. Arachidonic acid and prostaglandin E2 influence human osteoblast (MG63) response to titanium surface roughness.

    PubMed

    Dean, David D; Campbell, Casey M; Gruwell, Scott F; Tindall, John W M; Chuang, Hui-Hsiu; Zhong, Weinan; Schmitz, John P; Sylvia, Victor L

    2008-01-01

    Prior studies have shown that implant surface roughness affects osteoblast proliferation, differentiation, matrix synthesis, and local factor production. Further, cell response is modulated by systemic factors, such as 1,25(OH)2D3 and estrogen as well as mechanical forces. Based on the fact that peri-implant bone healing occurs in a site containing elevated amounts of prostaglandin E2 (PGE2), the hypothesis of the current study is that PGE2 and arachidonic acid (AA), the substrate used by cyclooxygenase to form PGE2, influence osteoblast response to implant surface roughness. To test this hypothesis, 4 different types of commercially pure titanium (cpTi) disks with surfaces of varying roughness (smooth Ti, R(a) 0.30 microm; smooth and acid etched Ti [SAE Ti], R(a) 0.40 microm; rough Ti, R(a) 4.3 microm; rough and acid etched Ti [RAE Ti], R(a) 4.15 (microm) were prepared. MG63 osteoblasts were seeded onto the surfaces, cultured to confluence, and then treated for the last 24 hours of culture with AA (0, 0.1, 1, and 10 nM), PGE2 (0, 1, 10, 25, and 100 nM), or the general cyclooxygenase inhibitor indomethacin (0 or 100 nM). At harvest, the effect of treatment on cell proliferation was assessed by measuring cell number and [3H]-thymidine incorporation, and the effect on cell differentiation was determined by measuring alkaline phosphatase (ALP) specific activity. The effect of AA and PGE2 on cell number was somewhat variable but showed a general decrease on plastic and smooth surfaces and an increase on rough surfaces. In contrast, [3H]-thymidine incorporation was uniformly decreased with treatment on all surfaces. ALP demonstrated the most prominent effect of treatment. On smooth surfaces, AA and PGE2 dose-dependently increased ALP, while on rough surfaces, treatment dose-dependently decreased enzyme specific activity. Indomethacin treatment had either no effect or a slightly inhibitory effect on [3H]-thymidine incorporation on all surfaces. In contrast, indomethacin

  15. Vegetable oils rich in alpha linolenic acid increment hepatic n-3 LCPUFA, modulating the fatty acid metabolism and antioxidant response in rats.

    PubMed

    Rincón-Cervera, Miguel Ángel; Valenzuela, Rodrigo; Hernandez-Rodas, María Catalina; Barrera, Cynthia; Espinosa, Alejandra; Marambio, Macarena; Valenzuela, Alfonso

    2016-08-01

    Alpha-linolenic acid (C18:3 n-3, ALA) is an essential fatty acid and the metabolic precursor of long-chain polyunsaturated fatty acids (LCPUFA) from the n-3 family with relevant physiological and metabolic roles: eicosapentaenoic acid (C20:5 n-3, EPA) and docosahexaenoic acid (C22:6 n-3, DHA). Western diet lacks of suitable intake of n-3 LCPUFA and there are recommendations to increase the dietary supply of such nutrients. Seed oils rich in ALA such as those from rosa mosqueta (Rosa rubiginosa), sacha inchi (Plukenetia volubis) and chia (Salvia hispanica) may constitute an alternative that merits research. This study evaluated hepatic and epididymal accretion and biosynthesis of n-3 LCPUFA, the activity and expression of Δ-5 and Δ-6 desaturase enzymes, the expression and DNA-binding activity of PPAR-α and SREBP-1c, oxidative stress parameters and the activity of antioxidative enzymes in rats fed sunflower oil (SFO, 1% ALA) as control group, canola oil (CO, 10% ALA), rosa mosqueta oil (RMO, 33% ALA), sacha inchi oil (SIO, 49% ALA) and chia oil (ChO, 64% ALA) as single lipid source. A larger supply of ALA increased the accretion of n-3 LCPUFA, the activity and expression of desaturases, the antioxidative status, the expression and DNA-binding of PPAR-α, the oxidation of fatty acids and the activity of antioxidant enzymes, whereas the expression and DNA-binding activity of SREBP-1c transcription factor and the biosynthetic activity of fatty acids declined. Results showed that oils rich in ALA such as SIO and ChO may trigger metabolic responses in rats such as those produced by n-3 PUFA. PMID:26995676

  16. Responses to n-3 fatty acid (LCPUFA) supplementation of gestating gilts, and lactating and weaned sows.

    PubMed

    Smit, M N; Patterson, J L; Webel, S K; Spencer, J D; Cameron, A C; Dyck, M K; Dixon, W T; Foxcroft, G R

    2013-05-01

    Feeding n-3 long-chain polyunsaturated fatty acids (LCPUFA) to gilts or sows has shown different responses to litter growth, pre-weaning mortality and subsequent reproductive performance of the sow. Two hypotheses were tested: (1) that feeding a marine oil-based supplement rich in protected n-3 LCPUFAs to gilts in established gestation would improve the growth performance of their litters; and (2) that continued feeding of the supplement during lactation and after weaning would offset the negative effects of lactational catabolism induced, using an established experimental model involving feed restriction of lactating primiparous sows. A total of 117 primiparous sows were pair-matched at day 60 of gestation by weight, and when possible, litter of origin, and were allocated to be either control sows (CON) fed standard gestation and lactation diets, or treated sows (LCPUFA) fed the standard diets supplemented with 84 g/day of a n-3 LCPUFA rich supplement, from day 60 of first gestation, through a 21-day lactation, and until euthanasia at day 30 of their second gestation. All sows were feed restricted during the last 7 days of lactation to induce catabolism, providing a background challenge against which to determine beneficial effects of n-3 LCPUFA supplementation on subsequent reproduction. In the absence of an effect on litter size or birth weight, n-3 LCPUFA tended to improve piglet BW gain from birth until 34 days after weaning (P = 0.06), while increasing pre-weaning mortality (P = 0.05). It did not affect energy utilization by the sow during lactation, thus not improving the catabolic state of the sows. Supplementation from weaning until day 30 of second gestation did not have an effect on embryonic weight, ovulation rate or early embryonic survival, but did increase corpora lutea (CL) weight (P = 0.001). Eicosapentaenoic acid and docosahexaenoic acid (DHA) levels were increased in sow serum and CL (P < 0.001), whereas only DHA levels increased in embryos (P

  17. Covalent and non-covalent curcumin loading in acid-responsive polymeric micellar nanocarriers

    NASA Astrophysics Data System (ADS)

    Gao, Min; Chen, Chao; Fan, Aiping; Zhang, Ju; Kong, Deling; Wang, Zheng; Zhao, Yanjun

    2015-07-01

    Poor aqueous solubility, potential degradation, rapid metabolism and elimination lead to low bioavailability of pleiotropic impotent curcumin. Herein, we report two types of acid-responsive polymeric micelles where curcumin was encapsulated via both covalent and non-covalent modes for enhanced loading capacity and on-demand release. Biodegradable methoxy poly(ethylene glycol)-poly(lactic acid) copolymer (mPEG-PLA) was conjugated with curcumin via a hydrazone linker, generating two conjugates differing in architecture (single-tail versus double-tail) and free curcumin was encapsulated therein. The two micelles exhibited similar hydrodynamic size at 95 ± 3 nm (single-tail) and 96 ± 3 nm (double-tail), but their loading capacities differed significantly at 15.0 ± 0.5% (w/w) (single-tail) and 4.8 ± 0.5% (w/w) (double-tail). Under acidic sink conditions (pH 5.0 and 6.0), curcumin displayed a faster release from the single-tail nanocarrier, which was correlated to a low IC50 of 14.7 ± 1.6 (μg mL-1) compared to the value of double-tail micelle (24.9 ± 1.3 μg mL-1) in HeLa cells. The confocal imaging and flow cytometry analysis demonstrated a superior capability of single-tail micelle for intracellular curcumin delivery, which was a consequence of the higher loading capacity and lower degree of mPEG surface coverage. In conclusion, the dual loading mode is an effective means to increase the drug content in the micellar nanocarriers whose delivery efficiency is highly dependent on its polymer-drug conjugate architecture. This strategy offers an alternative nanoplatform for intracellularly delivering impotent hydrophobic agents (i.e. curcumin) in an efficient stimuli-triggered way, which is valuable for the enhancement of curcumin’s efficacy in managing a diverse range of disorders.

  18. SFH2 regulates fatty acid synthase activity in the yeast Saccharomyces cerevisiae and is critical to prevent saturated fatty acid accumulation in response to haem and oleic acid depletion.

    PubMed

    Desfougères, Thomas; Ferreira, Thierry; Bergès, Thierry; Régnacq, Matthieu

    2008-01-01

    The yeast Saccharomyces cerevisiae is a facultative anaerobic organism. Under anaerobiosis, sustained growth relies on the presence of exogenously supplied unsaturated fatty acids and ergosterol that yeast is unable to synthesize in the absence of oxygen or upon haem depletion. In the absence of exogenous supplementation with unsaturated fatty acid, a net accumulation of SFA (saturated fatty acid) is observed that induces significant modification of phospholipid profile [Ferreira, Régnacq, Alimardani, Moreau-Vauzelle and Bergès (2004) Biochem. J. 378, 899-908]. In the present paper, we focus on the role of SFH2/CSR1, a hypoxic gene related to SEC14 and its involvement in lipid metabolism upon haem depletion in the absence of oleic acid supplementation. We observed that inactivation of SFH2 results in enhanced accumulation of SFA and phospholipid metabolism alterations. It results in premature growth arrest and leads to an exacerbated sensitivity to exogenous SFA. This phenotype is suppressed in the presence of exogenous oleic acid, or by a controlled expression of FAS1, one of the two genes encoding FAS. We present several lines of evidence to suggest that Sfh2p and oleic acid regulate SFA synthase in yeast at different levels: whereas oleic acid acts on FAS2 at the transcriptional level, we show that Sfh2p inhibits fatty acid synthase activity in response to haem depletion. PMID:17803462

  19. Effects of RAMEA-complexed polyunsaturated fatty acids on the response of human dendritic cells to inflammatory signals

    PubMed Central

    Rajnavölgyi, Éva; Laczik, Renáta; Kun, Viktor; Szente, Lajos

    2014-01-01

    Summary The n−3 fatty acids are not produced by mammals, although they are essential for hormone synthesis and maintenance of cell membrane structure and integrity. They have recently been shown to inhibit inflammatory reactions and also emerged as potential treatment options for inflammatory diseases, such as rheumatoid arthritis, asthma and inflammatory bowel diseases. Dendritic cells (DC) play a central role in the regulation of both innate and adaptive immunity and upon inflammatory signals they produce various soluble factors among them cytokines and chemokines that act as inflammatory or regulatory mediators. In this study we monitored the effects of α-linoleic acid, eicosapentaenoic acid and docosahexaenoic acid solubilized in a dimethyl sulfoxide (DMSO)/ethanol 1:1 mixture or as complexed by randomly methylated α-cyclodextrin (RAMEA) on the inflammatory response of human monocyte-derived dendritic cells (moDC). The use of RAMEA for enhancing aqueous solubility of n−3 fatty acids has the unambiguous advantage over applying RAMEB (the β-cyclodextrin analog), since there is no interaction with cell membrane cholesterol. In vitro differentiated moDC were left untreated or were stimulated by bacterial lipopolysaccharide and polyinosinic:polycytidylic acid, mimicking bacterial and viral infections, respectively. The response of unstimulated and activated moDC to n−3 fatty acid treatment was tested by measuring the cell surface expression of CD1a used as a phenotypic and CD83 as an activation marker of inflammatory moDC differentiation and activation by using flow cytometry. Monocyte-derived DC activation was also monitored by the secretion level of the pro- and anti-inflammatory cytokines IL-1β, TNF-α, IL-6, IL-10 and IL-12, respectively. We found that RAMEA-complexed n−3 fatty acids reduced the expression of CD1a protein in both LPS and Poly(I:C) stimulated moDC significantly, but most efficiently by eicosapentaenic acid, while no significant change

  20. Plasma amino acid response to single test meals in humans. V. Ethiopian preschool children given lowcost protein supplements.

    PubMed

    Ljungqvist, B G; Björnesjö, K B; Gebre-Medhin, M; Habte, D; Meeuwisse, G W; Mellander, O; Svanberg, U S

    1979-02-01

    The plasma amino acid response to single test meals was studied in preschool children, aged 9 months--5 years. The amount of protein given in each test meal was 1 g per kg body weight, which represented one-third of the daily intake of the children who were recovering from protein-energy malnutrition. The test meals given was gruels made from wheat mixed with a supplementary weaning food (Faffa or Superamin) or fish protein concentrate (FPC). The plasma amino acid responses were evaluated both as PAA ratios (a modification of the Longenecker and Hause method), and as deltaMR% (percentage change in the postprandial essential amino acid molar ratios according to Graham and Placko). Both evaluation models indicated that lysine, threonine and methionine were the limiting amino acids in the Faffa/wheat diet, and that lysine and threonine were limiting in the Superamin/wheat diet. All essential amino acids seemed to be supplied in adequate amounts in the FPC/wheat diet. These results were in close agreement with the amino acid score of the diets (based on chemical analysis). PMID:424653

  1. Life in protein-rich environments: the relA-independent response of Streptococcus pyogenes to amino acid starvation.

    PubMed

    Steiner, K; Malke, H

    2000-12-01

    Considering that group A streptococci are multiple auxotrophs that may encounter shortage of amino acids during specific stages of the infectious process, we studied their adaptive response to amino acid deprivation. We found that, in addition to the (p)ppGpp-mediated stringent response characterized previously, Streptococcus pyogenes exhibits a relA-independent response comprising transcriptional modulation of a specific subset of genes involved in pathogenesis. Genes/operons transcriptionally upregulated during starvation of both wild type and relA mutants included the two-component signal transduction system covRS, the positive regulator (ropB) of the pyrogenic exotoxin B gene, speB, the oligopeptide (opp) and dipeptide (dpp) permease systems and the pepB gene putatively involved in the intracellular processing of oligopeptides. Upregulation of covRS was accompanied by downregulation of ska, one of the target genes of the negative CovR regulator, and the net effect of amino acid starvation also favoured repression of speB. A significant feature of upregulated opp expression was stimulated readthrough transcription of the operon-internal oppA terminator, leading to increased mRNA levels for synthesis of the translocator complex relative to the substrate-binding protein. Based on these and previous results, a stimulus-response network is proposed that counteracts the stringent response and may enable the pathogen to mount a dynamic response to the protein-rich environment provided by its human host. PMID:11123674

  2. Acute exposure to realistic acid fog: Effects on respiratory function and airway responsiveness in asthmatics

    SciTech Connect

    Leduc, D.; De Vuyst, P.; Yernault, J.C.

    1995-11-01

    The biological effects of acid fog composed primarily of ammonium ions and sulfate are described. Subjects with asthma were exposed for one hour to sulfuric acid aerosol. Significant changes were not observed. Other asthma subjects were exposed to acid fog containing sulfate and ammonium ions. Again, pulmonary and bronchial function were not modified after inhalation.

  3. The Pepper CaOSR1 Protein Regulates the Osmotic Stress Response via Abscisic Acid Signaling

    PubMed Central

    Park, Chanmi; Lim, Chae Woo; Lee, Sung Chul

    2016-01-01

    Plants are sessile organisms, and their growth and development is detrimentally affected by environmental stresses such as drought and high salinity. Defense mechanisms are tightly regulated and complex processes, which respond to changing environmental conditions; however, the precise mechanisms that function under adverse conditions remain unclear. Here, we report the identification and functional characterization of the CaOSR1 gene, which functions in the adaptive response to abiotic stress. We found that CaOSR1 gene expression in pepper leaves was up-regulated after exposure to abscisic acid (ABA), drought, and high salinity. In addition, we demonstrated that the fusion protein of CaOSR1 with green fluorescent protein (GFP) is localized in the nucleus. We used CaOSR1-silenced pepper plants and CaOSR1-OX-overexpressing (OX) transgenic Arabidopsis plants to show that the CaOSR1 protein regulates the osmotic stress response. CaOSR1-silenced pepper plants showed increased drought susceptibility, and this was accompanied by a high transpiration rate. CaOSR1-OX plants displayed phenotypes that were hypersensitive to ABA and hyposensitive to osmotic stress, during the seed germination and seedling growth stages; furthermore, these plants exhibited enhanced drought tolerance at the adult stage, and this was characterized by higher leaf temperatures and smaller stomatal apertures because of ABA hypersensitivity. Taken together, our data indicate that CaOSR1 positively regulates osmotic stress tolerance via ABA-mediated cell signaling. These findings suggest an involvement of a novel protein in ABA and osmotic stress signalings in plants. PMID:27446121

  4. The Pepper CaOSR1 Protein Regulates the Osmotic Stress Response via Abscisic Acid Signaling.

    PubMed

    Park, Chanmi; Lim, Chae Woo; Lee, Sung Chul

    2016-01-01

    Plants are sessile organisms, and their growth and development is detrimentally affected by environmental stresses such as drought and high salinity. Defense mechanisms are tightly regulated and complex processes, which respond to changing environmental conditions; however, the precise mechanisms that function under adverse conditions remain unclear. Here, we report the identification and functional characterization of the CaOSR1 gene, which functions in the adaptive response to abiotic stress. We found that CaOSR1 gene expression in pepper leaves was up-regulated after exposure to abscisic acid (ABA), drought, and high salinity. In addition, we demonstrated that the fusion protein of CaOSR1 with green fluorescent protein (GFP) is localized in the nucleus. We used CaOSR1-silenced pepper plants and CaOSR1-OX-overexpressing (OX) transgenic Arabidopsis plants to show that the CaOSR1 protein regulates the osmotic stress response. CaOSR1-silenced pepper plants showed increased drought susceptibility, and this was accompanied by a high transpiration rate. CaOSR1-OX plants displayed phenotypes that were hypersensitive to ABA and hyposensitive to osmotic stress, during the seed germination and seedling growth stages; furthermore, these plants exhibited enhanced drought tolerance at the adult stage, and this was characterized by higher leaf temperatures and smaller stomatal apertures because of ABA hypersensitivity. Taken together, our data indicate that CaOSR1 positively regulates osmotic stress tolerance via ABA-mediated cell signaling. These findings suggest an involvement of a novel protein in ABA and osmotic stress signalings in plants. PMID:27446121

  5. Altering behavioral responses and dopamine transporter protein with antisense peptide nucleic acids.

    PubMed

    Tyler-McMahon, B M; Stewart, J A; Jackson, J; Bitner, M D; Fauq, A; McCormick, D J; Richelson, E

    2001-10-01

    The dopamine transporter (DAT) plays a role in locomotion and is an obligatory target for amphetamines. We designed and synthesized an antisense peptide nucleic acid (PNA) to rat DAT to examine the effect of this antisense molecule on locomotion and on responsiveness to amphetamines. Rats were injected intraperitoneally daily for 9 days with either saline, an antisense DAT PNA, a scrambled DAT PNA, or a mismatch DAT PNA. On days 7 and 9 after initial motility measurements were taken, the animals were challenged with 10 mg/kg of amphetamine and scored for motility. On day 7, there was no significant difference between the baseline levels of activity of any of the groups or their responses to amphetamine. On day 9, the antisense PNA-treated rats showed a statistically significant increase in their resting motility (P < 0.01). When these rats were challenged with amphetamine, motility of the saline-, scrambled PNA-, and mismatch PNA-treated animals showed increases of 31-, 36-, and 20-fold, respectively, while the antisense PNA-treated animals showed increases of only 3.4-fold (P < 0.01). ELISA results revealed a 32% decrease in striatal DAT in antisense PNA-treated rats compared with the saline, scrambled PNA, and mismatch PNA controls (P < 0.001). These results extend our previous findings that brain proteins can be knocked down in a specific manner by antisense molecules administered extracranially. Additionally, these results suggest some novel approaches for the treatment of diseases dependent upon the function of the dopamine transporter. PMID:11543728

  6. Intra-myocellular fatty acid metabolism plays a critical role in mediating responses to dietary restriction in Drosophila melanogaster

    PubMed Central

    Katewa, Subhash D.; Demontis, Fabio; Kolipinski, Marysia; Hubbard, Allan; Gill, Matthew S.; Perrimon, Norbert; Melov, Simon; Kapahi, Pankaj

    2012-01-01

    Summary Changes in fat content have been associated with dietary restriction (DR), but whether they play a causal role in mediating various responses to DR remains unknown. We demonstrate that upon DR, Drosophila melanogaster shift their metabolism towards increasing both fatty acid synthesis and breakdown, which is required for various responses to DR. Inhibition of fatty acid synthesis or oxidation genes specifically in the muscle tissue inhibited lifespan extension upon DR. Furthermore, DR enhances spontaneous activity of flies which was found to be dependent on the enhanced fatty acid metabolism. This increase in activity was found to be at least partially required for the lifespan extension upon DR. Over-expression of adipokinetic hormone (dAKH), the functional ortholog of glucagon, enhances fat metabolism, spontaneous activity and lifespan. Together, these results suggest that enhanced fat metabolism in the muscle and physical activity play a key role in the protective effects of DR. PMID:22768842

  7. Circulating concentrations of non-esterified fatty acids (NEFA) as mediators of the innate immune response in cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We previously reported that temperamental cattle have greater non-esterified fatty acid (NEFA) concentrations and an altered innate immune response compared to calm cattle. Therefore, this trial was designed to determine if increasing energy availability via a lipid infusion or bolus dextrose inject...

  8. Analysis of transporter responsible for the secretion of fusaric acid from the plant pathogen Fusarium oxysporum f. sp. vasinfectum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusaric acid (FA), a phytotoxic polyketide produced by Fusarium oxysporum f. sp. vasinfectum (Fov), has been suggested to be associated with disease symptoms on cotton. In response to a potential threat on cotton production by the introduction of high FA producing strains from Australia, new sources...

  9. Phospholipase C and diacylglycerol mediate olfactory responses to amino acids in the main olfactory epithelium of an amphibian.

    PubMed

    Sansone, Alfredo; Hassenklöver, Thomas; Syed, Adnan S; Korsching, Sigrun I; Manzini, Ivan

    2014-01-01

    The semi-aquatic lifestyle of amphibians represents a unique opportunity to study the molecular driving forces involved in the transition of aquatic to terrestrial olfaction in vertebrates. Most amphibians have anatomically segregated main and vomeronasal olfactory systems, but at the cellular and molecular level the segregation differs from that found in mammals. We have recently shown that amino acid responses in the main olfactory epithelium (MOE) of larval Xenopus laevis segregate into a lateral and a medial processing stream, and that the former is part of a vomeronasal type 2 receptor expression zone in the MOE. We hypothesized that the lateral amino acid responses might be mediated via a vomeronasal-like transduction machinery. Here we report that amino acid-responsive receptor neurons in the lateral MOE employ a phospholipase C (PLC) and diacylglycerol-mediated transduction cascade that is independent of Ca(2+) store depletion. Furthermore, we found that putative transient receptor potential (TRP) channel blockers inhibit most amino acid-evoked responses in the lateral MOE, suggesting that ion channels belonging to the TRP family may be involved in the signaling pathway. Our data show, for the first time, a widespread PLC- and diacylglycerol-dependent transduction cascade in the MOE of a vertebrate already possessing a vomeronasal organ. PMID:24489954

  10. The basic leucine zipper transcription factor ABSCISIC ACID RESPONSE ELEMENT-BINDING FACTOR2 is an important transcriptional regulator of abscisic acid-dependent grape berry ripening processes.

    PubMed

    Nicolas, Philippe; Lecourieux, David; Kappel, Christian; Cluzet, Stéphanie; Cramer, Grant; Delrot, Serge; Lecourieux, Fatma

    2014-01-01

    In grape (Vitis vinifera), abscisic acid (ABA) accumulates during fruit ripening and is thought to play a pivotal role in this process, but the molecular basis of this control is poorly understood. This work characterizes ABSCISIC ACID RESPONSE ELEMENT-BINDING FACTOR2 (VvABF2), a grape basic leucine zipper transcription factor belonging to a phylogenetic subgroup previously shown to be involved in ABA and abiotic stress signaling in other plant species. VvABF2 transcripts mainly accumulated in the berry, from the onset of ripening to the harvesting stage, and were up-regulated by ABA. Microarray analysis of transgenic grape cells overexpressing VvABF2 showed that this transcription factor up-regulates and/or modifies existing networks related to ABA responses. In addition, grape cells overexpressing VvABF2 exhibited enhanced responses to ABA treatment compared with control cells. Among the VvABF2-mediated responses highlighted in this study, the synthesis of phenolic compounds and cell wall softening were the most strongly affected. VvABF2 overexpression strongly increased the accumulation of stilbenes that play a role in plant defense and human health (resveratrol and piceid). In addition, the firmness of fruits from tomato (Solanum lycopersicum) plants overexpressing VvABF2 was strongly reduced. These data indicate that VvABF2 is an important transcriptional regulator of ABA-dependent grape berry ripening. PMID:24276949

  11. Optimization of polyphenol extraction from red grape pomace using aqueous glycerol/tartaric acid mixtures and response surface methodology.

    PubMed

    Makris, Dimitris P; Passalidi, Vassiliki; Kallithraka, Stamatina; Mourtzinos, Ioannis

    2016-01-01

    Grape pomace is a food industry waste containing a high burden of antioxidant polyphenols and several methodologies have been developed for their efficient extraction. However, a sustainable and environmentally friendly process should involve recovery means composed of benign, non-toxic solvents, such as tartaric acid and glycerol, which are natural food constituents. In this line, this study examined the extraction of polyphenols using aqueous tartaric acid/glycerol solutions. The aim was to assess the role of acid and glycerol concentration in the extraction yield, employing a Box-Behnken experimental design and response surface methodology. The results showed that solutions containing only glycerol (20%, w/v) are more suitable for retrieving polyphenols, flavonoids, and pigments from grape pomace, while tartaric acid exerted a negative effect in this regard, when tested at concentrations up to 2% (w/v). PMID:25806718

  12. Comparison of postprandial phenolic acid excretions and glucose responses after ingestion of breads with bioprocessed or native rye bran.

    PubMed

    Lappi, Jenni; Aura, Anna-Marja; Katina, Kati; Nordlund, Emilia; Kolehmainen, Marjukka; Mykkänen, Hannu; Poutanen, Kaisa

    2013-06-01

    Rye bran contains a high amount of phenolic acids with potential health promoting effects. However, due to binding to dietary fibre, the phenolic acids are poorly absorbed in human body. We used bioprocessing with enzymes and yeast to release phenolic acids from the fibre complex and studied the effect of bioprocessing on absorption of phenolic acids in healthy humans. White wheat breads fortified with bioprocessed or native rye bran, and wholegrain rye bread and white wheat bread as controls were served to 15 subjects in a randomized order in the cross-over design. Urine was collected at the basal state and over 24 hours in four-, eight-, and twelve-hour periods and analyzed for phenolic acids and their metabolites with gas chromatography. A total of six blood samples were taken over four hours to study the effect of the bread ingestion on postprandial glucose and insulin responses. Bioprocessing of rye bran increased the proportion of free ferulic acid (FA) and soluble arabinoxylan in the bread. Ingestion of the white wheat bread fortified with bioprocessed rye bran increased (p < 0.001) urinary excretion of FA particularly during the first four hours, indicating increased absorption of FA from the small intestine. The postprandial glucose and insulin responses were similar between these breads. Bioprocessing of rye bran did not affect excretion of benzoic, phenylpropionic, and phenylacetic acid metabolites. As a conclusion, bioprocessed rye bran as compared with native rye bran increased absorption of FA from the small intestine, but did not improve postprandial glucose and insulin responses. PMID:23674066

  13. Potential role of salicylic acid in modulating diacylglycerol homeostasis in response to freezing temperatures in Arabidopsis

    PubMed Central

    Tan, Wei-Juan; Xiao, Shi; Chen, Qin-Fang

    2015-01-01

    In our recent article in Molecular Plant, we reported that 3 lipase-like defense regulators SENESCENCE-ASSOCIATED GENE101 (SAG101), ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1) and PHYTOALEXIN DEFICIENT4 (PAD4) are involved in the regulation of freezing tolerance in Arabidopsis. The transcripts of SAG101, EDS1 and PAD4 were inducible by cold stress and their knockout or knockdown mutants exhibited enhanced chilling and freezing tolerance in comparison to the wild type. The freezing tolerance phenotype showed in the sag101, eds1 and pad4 mutants was correlated with the transcriptional upregulation of C-REPEAT/DRE BINDING FACTORs (CBFs) and their regulons as well as increased levels of proline. Upon cold exposure, the sag101, eds1 and pad4 mutants showed ameliorated cell death and accumulation of hydrogen peroxide, which were highly induced by freezing stress in the wild-type leaves. Moreover, the contents of salicylic acid (SA) and diacylglycerol (DAG) were significantly decreased in the sag101, eds1 and pad4 mutants compared to the wild type. Taken together, our results suggest that the SAG101, EDS1 and PAD4 are negative regulators in the freezing response and function, at least in part, by modulating the homeostasis of SA and DAG in Arabidopsis. PMID:26340231

  14. Effect of fatty acid anilides on immune responses of Swiss mice.

    PubMed Central

    Blasco, R; Ruiz-Gutierrez, V

    1992-01-01

    The possible relationship between fatty acid anilides and the toxic oil syndrome (TOS) which appeared in Spain in 1981 has been debated during recent years. These anilides have been detected as anomalous compound in toxic oils analysed. After treatment with one daily dose of 50 mg/kg of oleilanilide (88.86% pure) for 5 days, animals showed a tendency towards progressive loss of body weight and a significant increase in serum concentration of immunoglobulins. The percentage of suppressor T cells in spleen diminished significantly compared with the control group. Consequently, an increase in the helper T cells/suppressor T cells was also observed. The production of IgM and IgG in culture was significantly higher than in controls and no differences were seen in IgA synthesis. The functional studies of generation of specific IgM, IgA and IgG suppressor cells at variable doses of concanavalin A (Con A) showed paradoxical behaviour of suppressor T cells generated by low doses of Con A. A similar change occurred at higher doses of Con A. These results suggest that low-dose treatment with oleilanilides induces an alteration in the immune response in Swiss mice. PMID:1385764

  15. EGCG Attenuates Uric Acid-Induced Inflammatory and Oxidative Stress Responses by Medicating the NOTCH Pathway

    PubMed Central

    Xie, Hua; Sun, Jianqin; Chen, Yanqiu; Zong, Min; Li, Shijie; Wang, Yan

    2015-01-01

    Background. The aim of this study is to investigate whether (-)-epigallocatechin-3-gallate (EGCG) can prevent the UA-induced inflammatory effect of human umbilical vein endothelial cells (HUVEC) and the involved mechanisms in vitro. Methods. HUVEC were subjected to uric acid (UA) with or without EGCG treatment. RT-PCR and western blots were performed to determine the level of inflammation marker. The antioxidant activity was evaluated by measuring scavenged reactive oxygen species (ROS). Functional studies of the role of Notch-1 in HUVEC lines were performed using RNA interference analyses. Results. UA significantly increased the expressions of IL-6, ICAM-1, TNF-α, and MCP-1 and the production of ROS in HUVEC. Meanwhile, the expression of Notch-1 and its downstream effects significantly increased. Using siRNA, inhibition of Notch-1 signaling significantly impeded the expressions of inflammatory cytokines under UA treatment. Interestingly, EGCG suppressed the expressions of inflammatory cytokines and the generation of ROS. Western blot analysis of Notch-1 showed that EGCG significantly decreased the expressions of inflammatory cytokines through Notch-1 signaling pathways. Conclusions. In summary, our findings indicated that Notch-1 plays an important role in the UA-induced inflammatory response, and the downregulation of Notch-1 by EGCG could be an effective approach to decrease inflammation and oxidative stress induced by UA. PMID:26539255

  16. A ferulic acid (FA)-eluting system for biodegradable magnesium stent: Cells response of HUVECs.

    PubMed

    Zhang, Erlin; Shen, Feng

    2015-08-01

    A new drug-eluting system was designed for biodegradable magnesium stents, in which ferulic acid (FA) was used as drug due to its promotion function to endothelial cells and PHBHHx as drug delivery due to its biodegradability and biocompatibility. A 5 and 10% FA were added in PHBHHx to prepare FA containing PHBHHX films. The cell adhesion, spreading and proliferation on these films was investigated in order to assess cell response of HUVECs. It was also found that FA enhanced the adhesion, spreading and proliferation of HUVECs in a dose-dependent manner. Cell viability after H2 O2 injury and NO production of HUVECs were also studied. The results indicated that FA effectively inhibited H2 O2 -induced injury and promotes NO production. It was also shown that alkali treatment improved the cell adhesion, spreading and proliferation while the treatment reduces the FA release and in turn reduces the inhibition on H2 O2 -induced injury and NO production. However, alkali treatment itself had no influence on the H2 O2 induced injure and NO production. The tensile shear strength between the FA containing coating and Mg substrate was also tested. All results demonstrated that FA containing PHBHHx films exhibited strong promotion to the endothelialization and could be a choice for surface modification of magnesium stent. PMID:25630748

  17. A pH- and thermo-responsive poly(amino acid)-based drug delivery system.

    PubMed

    Liu, Na; Li, Bingqiang; Gong, Chu; Liu, Yuan; Wang, Yanming; Wu, Guolin

    2015-12-01

    A pH- and thermo-responsive poly(amino acid)-based amphiphilic copolymer was developed, functioning as a tumour targeting drug delivery system with good biocompatibility and biodegradability. To provide multi-stimuli sensitivity characteristics to the poly(amino acid)s, the polyaspartamide scaffold has been functionalized with N,N-diisopropylamide groups via aminolysis reaction of polysuccinimide. PEG chains have also been chemically grafted to the poly(amino acid) backbone through acid-labile hydrazone linkages, providing a removable shield for the poly(amino acid) based nanoparticles. Furthermore, doxorubicin was chemically linked to the copolymer chain via hydrazone bonds, acting as the hydrophobic moiety to drive the polymeric self-assembly. Free doxorubicin molecules could be encapsulated into the self-assembled nanoparticles via hydrophobic interactions and molecular π-π stacking. The results obtained show that the drug release can be triggered by the temperature with a significantly increased release being observed under acidic conditions. The cytotoxicity behaviour of the copolymers and drug-loaded nanoparticles was investigated in vitro at varying pH values and different temperatures. In doing so, superior characteristics concerning compatibility and anti-cancer activity could be observed. PMID:26454546

  18. Plasma membrane phospholipase A2 controls hepatocellular fatty acid uptake and is responsive to pharmacological modulation: implications for nonalcoholic steatohepatitis.

    PubMed

    Stremmel, Wolfgang; Staffer, Simone; Wannhoff, Andreas; Pathil, Anita; Chamulitrat, Walee

    2014-07-01

    Excess hepatic fat accumulation leads to nonalcoholic steatohepatitis (NASH), a serious threat to health for which no effective treatment is available. However, the mechanism responsible for fatty acid uptake by hepatocytes remains unclear. Using the human hepatocyte-derived tumor cell line HepG2, we found that fatty acid influx is mediated by a heterotetrameric plasma membrane protein complex consisting of plasma membrane fatty acid-binding protein, caveolin-1, CD36, and calcium-independent membrane phospholipase A2 (iPLA2β). Blocking iPLA2β with the bile acid-phospholipid conjugate ursodeoxycholate-lysophosphatidylethanolamide (UDCA-LPE) caused the dissociation of the complex, thereby inhibiting fatty acid influx (IC50 47 μM), and suppressed the synthesis of all subunits through a reduction in lysophosphatidylcholine from 8.0 to 3.5 μmol/mg of protein and corresponding depletion of phosphorylated c-Jun N-terminal kinase. These findings were substantiated by an observed 56.5% decrease in fatty acid influx in isolated hepatocytes derived from iPLA2β-knockout mice. Moreover, steatosis and inflammation were abrogated by UDCA-LPE treatment in a cellular model of NASH. Thus, iPLA2β acts as an upstream checkpoint for mechanisms that regulate fatty acid uptake, and its inhibition by UDCA-LPE qualifies this nontoxic compound as a therapeutic candidate for the treatment of NASH.-Stremmel, W., Staffer, S., Wannhoff, A., Pathil, A., Chamulitrat, W. Plasma membrane phospholipase A2 controls hepatocellular fatty acid uptake and is responsive to pharmacological modulation: implications for nonalcoholic steatohepatitis. PMID:24719358

  19. Host-derived extracellular nucleic acids enhance innate immune responses, induce coagulation, and prolong survival upon infection in insects.

    PubMed

    Altincicek, Boran; Stötzel, Sabine; Wygrecka, Malgorzata; Preissner, Klaus T; Vilcinskas, Andreas

    2008-08-15

    Extracellular nucleic acids play important roles in human immunity and hemostasis by inducing IFN production, entrapping pathogens in neutrophil extracellular traps, and providing procoagulant cofactor templates for induced contact activation during mammalian blood clotting. In this study, we investigated the functions of extracellular RNA and DNA in innate immunity and hemolymph coagulation in insects using the greater wax moth Galleria mellonella a reliable model host for many insect and human pathogens. We determined that coinjection of purified Galleria-derived nucleic acids with heat-killed bacteria synergistically increases systemic expression of antimicrobial peptides and leads to the depletion of immune-competent hemocytes indicating cellular immune stimulation. These activities were abolished when nucleic acids had been degraded by nucleic acid hydrolyzing enzymes prior to injection. Furthermore, we found that nucleic acids induce insect hemolymph coagulation in a similar way as LPS. Proteomic analyses revealed specific RNA-binding proteins in the hemolymph, including apolipoproteins, as potential mediators of the immune response and hemolymph clotting. Microscopic ex vivo analyses of Galleria hemolymph clotting reactions revealed that oenocytoids (5-10% of total hemocytes) represent a source of endogenously derived extracellular nucleic acids. Finally, using the entomopathogenic bacterium Photorhabdus luminescens as an infective agent and Galleria caterpillars as hosts, we demonstrated that injection of purified nucleic acids along with P. luminescens significantly prolongs survival of infected larvae. Our results lend some credit to our hypothesis that host-derived nucleic acids have independently been co-opted in innate immunity of both mammals and insects, but exert comparable roles in entrapping pathogens and enhancing innate immune responses. PMID:18684961

  20. Enzymatic production of infant milk fat analogs containing palmitic acid: optimization of reactions by response surface methodology.

    PubMed

    Maduko, C O; Akoh, C C; Park, Y W

    2007-05-01

    Infant milk fat analogs resembling human milk fat were synthesized by an enzymatic interesterification between tripalmitin, coconut oil, safflower oil, and soybean oil in hexane. A commercially immobilized 1,3-specific lipase, Lipozyme RM IM, obtained from Rhizomucor miehei was used as a biocatalyst. The effects of substrate molar ratio, reaction time, and incubation temperature on the incorporation of palmitic acid at the sn-2 position of the triacylglycerols were investigated. A central composite design with 5 levels and 3 factors consisting of substrate ratio, reaction temperature, and incubation time was used to model and optimize the reaction conditions using response surface methodology. A quadratic model using multiple regressions was then obtained for the incorporation of palmitic acid at the sn-2 positions of glycerols as the response. The coefficient of determination (R2) value for the model was 0.845. The incorporation of palmitic acid appeared to increase with the decrease in substrate molar ratio and increase in reaction temperature, and optimum incubation time occurred at 18 h. The optimal conditions generated from the model for the targeted 40% palmitic acid incorporation at the sn-2 position were 3 mol/mol, 14.4 h, and 55 degrees C; and 2.8 mol/mol, 19.6 h, and 55 degrees C for substrate ratio (moles of total fatty acid/moles of tripalmitin), time, and temperature, respectively. Infant milk fat containing fatty acid composition and sn-2 fatty acid profile similar to human milk fat was successfully produced. The fat analogs produced under optimal conditions had total and sn-2 positional palmitic acid levels comparable to that of human milk fat. PMID:17430912

  1. Lysophosphatidic acid receptor-5 negatively regulates cellular responses in mouse fibroblast 3T3 cells

    SciTech Connect

    Dong, Yan; Hirane, Miku; Araki, Mutsumi; Fukushima, Nobuyuki; Tsujiuchi, Toshifumi

    2014-04-04

    Highlights: • LPA{sub 5} inhibits the cell growth and motile activities of 3T3 cells. • LPA{sub 5} suppresses the cell motile activities stimulated by hydrogen peroxide in 3T3 cells. • Enhancement of LPA{sub 5} on the cell motile activities inhibited by LPA{sub 1} in 3T3 cells. • The expression and activation of Mmp-9 were inhibited by LPA{sub 5} in 3T3 cells. • LPA signaling via LPA{sub 5} acts as a negative regulator of cellular responses in 3T3 cells. - Abstract: Lysophosphatidic acid (LPA) signaling via G protein-coupled LPA receptors (LPA{sub 1}–LPA{sub 6}) mediates a variety of biological functions, including cell migration. Recently, we have reported that LPA{sub 1} inhibited the cell motile activities of mouse fibroblast 3T3 cells. In the present study, to evaluate a role of LPA{sub 5} in cellular responses, Lpar5 knockdown (3T3-L5) cells were generated from 3T3 cells. In cell proliferation assays, LPA markedly stimulated the cell proliferation activities of 3T3-L5 cells, compared with control cells. In cell motility assays with Cell Culture Inserts, the cell motile activities of 3T3-L5 cells were significantly higher than those of control cells. The activity levels of matrix metalloproteinases (MMPs) were measured by gelatin zymography. 3T3-L5 cells stimulated the activation of Mmp-2, correlating with the expression levels of Mmp-2 gene. Moreover, to assess the co-effects of LPA{sub 1} and LPA{sub 5} on cell motile activities, Lpar5 knockdown (3T3a1-L5) cells were also established from Lpar1 over-expressing (3T3a1) cells. 3T3a1-L5 cells increased the cell motile activities of 3T3a1 cells, while the cell motile activities of 3T3a1 cells were significantly lower than those of control cells. These results suggest that LPA{sub 5} may act as a negative regulator of cellular responses in mouse fibroblast 3T3 cells, similar to the case for LPA{sub 1}.

  2. Improved cellular response of ion modified poly(lactic acid-co-glycolic acid) substrates for mouse fibroblast cells.

    PubMed

    Adhikari, Ananta Raj; Geranpayeh, Tanya; Chu, Wei Kan; Otteson, Deborah C

    2016-03-01

    In this report, the effects of argon (Ar) ion irradiation on poly(lactic acid-co-glycolic acid) (PLGA) substrates on biocompatibility were studied. PLGA scaffold substrates were prepared by spin coating glass surfaces with PLGA dissolved in anhydrous chloroform. Previously, we showed that surface modifications of PLGA films using ion irradiation modulate the inherent hydrophobicity of PLGA surface. Here we show that with increasing ion dose (1×10(12) to 1×10(14) ions/cm(2)), hydrophobicity and surface roughness decreased. Biocompatibility for NIH3T3 mouse fibroblast cells was increased by argon irradiation of PLGA substrates. On unirradiated PLGA films, fibroblasts had a longer doubling time and cell densities were 52% lower than controls after 48 h in vitro. Argon irradiated PLGA substrates supported growth rates similar to control. Despite differences in cell cycle kinetics, there was no detectible cytotoxicity observed on any substrate. This demonstrates that argon ion irradiation can be used to tune the surface microstructure and generate substrates that are more compatible for the cell growth and proliferation. PMID:26706518

  3. pH-responsive biocompatible fluorescent polymer nanoparticles based on phenylboronic acid for intracellular imaging and drug delivery

    NASA Astrophysics Data System (ADS)

    Li, Shengliang; Hu, Kelei; Cao, Weipeng; Sun, Yun; Sheng, Wang; Li, Feng; Wu, Yan; Liang, Xing-Jie

    2014-10-01

    To address current medical challenges, there is an urgent need to develop drug delivery systems with multiple functions, such as simultaneous stimuli-responsive drug release and real-time imaging. Biocompatible polymers have great potential for constructing smart multifunctional drug-delivery systems through grafting with other functional ligands. More importantly, novel biocompatible polymers with intrinsic fluorescence emission can work as theranostic nanomedicines for real-time imaging and drug delivery. Herein, we developed a highly fluorescent nanoparticle based on a phenylboronic acid-modified poly(lactic acid)-poly(ethyleneimine)(PLA-PEI) copolymer loaded with doxorubicin (Dox) for intracellular imaging and pH-responsive drug delivery. The nanoparticles exhibited superior fluorescence properties, such as fluorescence stability, no blinking and excitation-dependent fluorescence behavior. The Dox-loaded fluorescent nanoparticles showed pH-responsive drug release and were more effective in suppressing the proliferation of MCF-7 cells. In addition, the biocompatible fluorescent nanoparticles could be used as a tool for intracellular imaging and drug delivery, and the process of endosomal escape was traced by real-time imaging. These pH-responsive and biocompatible fluorescent polymer nanoparticles, based on phenylboronic acid, are promising tools for intracellular imaging and drug delivery.To address current medical challenges, there is an urgent need to develop drug delivery systems with multiple functions, such as simultaneous stimuli-responsive drug release and real-time imaging. Biocompatible polymers have great potential for constructing smart multifunctional drug-delivery systems through grafting with other functional ligands. More importantly, novel biocompatible polymers with intrinsic fluorescence emission can work as theranostic nanomedicines for real-time imaging and drug delivery. Herein, we developed a highly fluorescent nanoparticle based on a

  4. In vivo responses of single olfactory receptor neurons of channel catfish to binary mixtures of amino acids.

    PubMed

    Kang, J; Caprio, J

    1997-01-01

    For the first time in any vertebrate, in vivo responses of single olfactory receptor neurons to odorant mixtures were studied quantitatively. Extracellular electrophysiological response of 54 single olfactory receptor neurons from 23 channel catfish, Ictalurus punctatus, to binary mixtures of amino acids and to their components were recorded simultaneously with the electroolfactogram (EOG). For 57% (73 of 128) of the tests, no significant change (N) from spontaneous activity occurred. Responses to the remaining 55 tests of binary mixtures were excitatory (E; 13%) or suppressive (S; 30%). No response type was associated with any specific mixture across the neurons sampled. Eighty-six percent of the responses of catfish olfactory receptor neurons to binary mixtures were classified similar to at least one of the component responses, a percentage comparable (i.e., 89%) with that observed for single olfactory bulb neurons in the same species to equivalent binary mixtures. The responses of single olfactory receptor neurons to component-similar binary mixtures (i.e., component responses were both E, both S, and both N, respectively) were generally (80% of 59 tests) classified similar to the responses to the components. For E+N and S+N binary mixtures, the N component often (66% of 58 tests) reduced or concealed (i.e., "masked") the excitatory and suppressive responses, respectively. For the majority (6 of 11 tests) of E + S binary mixtures, null activity resulted. Responses to the remaining five tests were either excitatory (n = 3) or suppressive (n = 2). PMID:9120550

  5. Latency, duration and dose response relationships of amino acid effects on human muscle protein synthesis.

    PubMed

    Rennie, Michael J; Bohé, Julien; Wolfe, Robert R

    2002-10-01

    The components of the stimulatory effect of food on net deposition of protein are beginning to be identified and separated. One of the most important of these appears to be the effect of amino acids per se in stimulating muscle anabolism. Amino acids appear to have a linear stimulatory effect within the range of normal diurnal plasma concentrations from postabsorptive to postprandial. Within this range, muscle protein synthesis (measured by incorporation of stable isotope tracers of amino acids into biopsied muscle protein) appears to be stimulated approximately twofold; however, little further increase occurs when very high concentrations of amino acids (>2.5 times the normal postabsorptive plasma concentration) are made available. Amino acids provided in surfeit of the ability of the system to synthesize protein are disposed of by oxidation, ureagenesis and gluconeogenesis. The stimulatory effect of amino acids appears to be time dependent; a square wave increase in the availability of amino acids causes muscle protein synthesis to be stimulated and to fall back to basal values, despite continued amino acid availability. The relationship between muscle protein synthesis and insulin availability suggests that most of the stimulatory effects occur at low insulin concentrations, with large increases having no effect. These findings may have implications for our understanding of the body's requirements for protein. The maximal capacity for storage of amino acids as muscle protein probably sets an upper value on the extent to which amino acids can be stored after a single meal. PMID:12368422

  6. Overexpression of G-Protein-Coupled Receptor 40 Enhances the Mitogenic Response to Epoxyeicosatrienoic Acids

    PubMed Central

    Ma, Seong Kwon; Wang, Yinqiu; Chen, Jianchun; Zhang, Ming-Zhi; Harris, Raymond C.; Chen, Jian-Kang

    2015-01-01

    The cytochrome P450 epoxygenase-dependent arachidonic acid metabolites, epoxyeicosatrienoic acids (EETs), are potent survival factors and mitogens for renal epithelial cells, but the molecular identity in the cells that initiates the mitogenic signaling of EETs has remained elusive. We screened kidney cell lines for the expression of G-protein-coupled receptor 40 (GPR40) and found that the porcine renal tubular epithelial cell line LLCPKcl4, which has been previously demonstrated to be sensitive to the mitogenic effect of EETs, expresses higher levels of GPR40 mRNA and protein than the human embryonic kidney cell line HEK293. EETs induced only a weak mitogenic EGFR signaling and mild cell proliferation in HEK293 cells. To determine whether GPR40 expression level is what mediates the mitogenic sensitivity of cells to EETs, we created a human GPR40 (hGPR40) cDNA construct and transfected it into HEK293 cells and picked up a number of stable transfectants. We found that GPR40 overexpression in HEK293 cells indeed significantly enhanced EET-induced cell proliferation and markedly augmented EGFR phosphorylation ERK activation, which were inhibited by the EGFR tyrosine kinase inhibitor, AG1478, or the HB-EGF inhibitor, CRM197. EETs significantly enhanced release of soluble HB-EGF, a natural ligand of EGFR, into the culture medium of hGPR40-transfected HEK293 cells, compared to empty vector-transfected cells. In mouse kidneys, markedly higher level of GPR40 protein was found in the cortex and outer stripe of outer medulla compared to the inner stripe of outer medulla and inner medulla. In situ hybridization confirmed that GPR40 mRNA was localized to a subset of renal tubules in the kidney, including the cortical collecting duct. Thus, this study provides the first demonstration that upregulation of GPR40 expression enhances the mitogenic response to EETs and a relatively high expression level of GPR40 is detected in a subset of tubules including cortical collecting ducts

  7. Assessing amino acid racemization variability in coral intra-crystalline protein for geochronological applications

    NASA Astrophysics Data System (ADS)

    Hendy, Erica J.; Tomiak, Peter J.; Collins, Matthew J.; Hellstrom, John; Tudhope, Alexander W.; Lough, Janice M.; Penkman, Kirsty E. H.

    2012-06-01

    Over 500 Free Amino Acid (FAA) and corresponding Total Hydrolysed Amino Acid (THAA) analyses were completed from eight independently-dated, multi-century coral cores of massive Porites sp. colonies. This dataset allows us to re-evaluate the application of amino acid racemization (AAR) for dating late Holocene coral material, 20 years after Goodfriend et al. (GCA56 (1992), 3847) first showed AAR had promise for developing chronologies in coral cores. This re-assessment incorporates recent method improvements, including measurement by RP-HPLC, new quality control approaches (e.g. sampling and sub-sampling protocols, statistically-based data screening criteria), and cleaning steps to isolate the intra-crystalline skeletal protein. We show that the removal of the extra-crystalline contaminants and matrix protein is the most critical step for reproducible results and recommend a protocol of bleaching samples in NaOCl for 48 h to maximise removal of open system proteins while minimising the induced racemization. We demonstrate that AAR follows closed system behaviour in the intra-crystalline fraction of the coral skeletal proteins. Our study is the first to assess the natural variability in intra-crystalline AAR between colonies, and we use coral cores taken from the Great Barrier Reef, Australia, and Jarvis Island in the equatorial Pacific to explore variability associated with different environmental conditions and thermal histories. Chronologies were developed from THAA Asx D/L, Ala D/L, Glx D/L and FAA Asx D/L for each core and least squares Monte Carlo modelling applied in order to quantify uncertainty of AAR age determinations and assess the level of dating resolution possible over the last 5 centuries. AAR within colonies follow consistent stratigraphic aging. However, there are systematic differences in rates between the colonies, which would preclude direct comparison from one colony to another for accurate age estimation. When AAR age models are developed from

  8. Assessing amino acid racemization variability in coral intra-crystalline protein for geochronological applications.

    PubMed

    Hendy, Erica J; Tomiak, Peter J; Collins, Matthew J; Hellstrom, John; Tudhope, Alexander W; Lough, Janice M; Penkman, Kirsty E H

    2012-06-01

    Over 500 Free Amino Acid (FAA) and corresponding Total Hydrolysed Amino Acid (THAA) analyses were completed from eight independently-dated, multi-century coral cores of massive Porites sp. colonies. This dataset allows us to re-evaluate the application of amino acid racemization (AAR) for dating late Holocene coral material, 20 years after Goodfriend et al. (GCA 56 (1992), 3847) first showed AAR had promise for developing chronologies in coral cores. This re-assessment incorporates recent method improvements, including measurement by RP-HPLC, new quality control approaches (e.g. sampling and sub-sampling protocols, statistically-based data screening criteria), and cleaning steps to isolate the intra-crystalline skeletal protein. We show that the removal of the extra-crystalline contaminants and matrix protein is the most critical step for reproducible results and recommend a protocol of bleaching samples in NaOCl for 48 h to maximise removal of open system proteins while minimising the induced racemization. We demonstrate that AAR follows closed system behaviour in the intra-crystalline fraction of the coral skeletal proteins. Our study is the first to assess the natural variability in intra-crystalline AAR between colonies, and we use coral cores taken from the Great Barrier Reef, Australia, and Jarvis Island in the equatorial Pacific to explore variability associated with different environmental conditions and thermal histories. Chronologies were developed from THAA Asx D/L, Ala D/L, Glx D/L and FAA Asx D/L for each core and least squares Monte Carlo modelling applied in order to quantify uncertainty of AAR age determinations and assess the level of dating resolution possible over the last 5 centuries. AAR within colonies follow consistent stratigraphic aging. However, there are systematic differences in rates between the colonies, which would preclude direct comparison from one colony to another for accurate age estimation. When AAR age models are developed

  9. Optimization of lactic acid production by pellet-form Rhizopus oryzae in 3-L airlift bioreactor using response surface methodology.

    PubMed

    Maneeboon, Thanapoom; Vanichsriratana, Wirat; Pomchaitaward, Chaiyaporn; Kitpreechavanich, Vichien

    2010-05-01

    The influence of two key environmental factors, pH and oxygen transfer coefficient (k(L)a), was evaluated on the lactic acid production as the main answer and, on the size of cell pellets of the fungal strain Rhizopus oryzae KPS106, as second dependant answer by response surface methodology using a central composite design. The results of the analysis of variance and modeling demonstrated that pH and k(L)a had a significant effect on lactic acid production by this strain. However, no interaction was observed between these two experimental factors. pH and k(L)a had no significant influence on the pellet size. Optimal pH and k(L)a of the fermentation medium for lactic acid production from response surface analysis was 5.85 and of 3.6 h(-1), respectively. The predicted and experimental lactic acid maximal values were 75.4 and 72.0 g/l, respectively, with pellets of an average of 2.54 +/- 0.41 mm. Five repeated batches in series were conducted with a mean lactic acid production of 77.54 g/l. The productivity was increased from 0.75 in the first batch to 0.99 g/l h in the last fifth batch. PMID:20091139

  10. Milk fatty acid composition, rumen microbial population, and animal performances in response to diets rich in linoleic acid supplemented with chestnut or quebracho tannins in dairy ewes.

    PubMed

    Buccioni, A; Pauselli, M; Viti, C; Minieri, S; Pallara, G; Roscini, V; Rapaccini, S; Marinucci, M Trabalza; Lupi, P; Conte, G; Mele, M

    2015-02-01

    The aim of the study was to evaluate milk fatty acid (FA) profile, animal performance, and rumen microbial population in response to diets containing soybean oil supplemented or not with chestnut and quebracho tannins in dairy ewes. Eighteen Comisana ewes at 122±6 d in milking were allotted into 3 experimental groups. Diets were characterized by chopped grass hay administered ad libitum and by 800 g/head and day of 3 experimental concentrates containing 84.5 g of soybean oil/kg of dry matter (DM) and 52.8 g/kg of DM of bentonite (control diet), chestnut tannin extract (CHT diet), or quebracho tannin extract (QUE diet). The trial lasted 4 wk. Milk yield was recorded daily, and milk composition and blood parameters were analyzed weekly. At the end of the experiment, samples of rumen fluid were collected to analyze pH, volatile fatty acid profile, and the relative proportions of Butyrivibrio fibrisolvens and Butyrivibrio proteoclasticus in the rumen microbial population. Hepatic functionality, milk yield, and gross composition were not affected by tannin extracts, whereas milk FA composition was characterized by significant changes in the concentration of linoleic acid (CHT +2.77% and QUE +9.23%), vaccenic acid (CHT +7.07% and QUE +13.88%), rumenic acid (CHT -1.88% and QUE +24.24%), stearic acid (CHT + 8.71% and QUE -11.45%), and saturated fatty acids (CHT -0.47% and QUE -3.38%). These differences were probably due to the ability of condensed versus hydrolyzable tannins to interfere with rumen microbial metabolism, as indirectly confirmed by changes in the relative proportions of B. fibrisolvens and B. proteoclasticus populations and by changes in the molar proportions of volatile fatty acids. The effect of the CHT diet on the milk FA profile and microbial species considered in this trial was intermediate between that of QUE and the control diet, suggesting a differential effect of condensed and hydrolyzable tannins on rumen microbes. Compared with control animals

  11. Retinoic acid activates human inducible nitric oxide synthase gene through binding of RAR{alpha}/RXR{alpha} heterodimer to a novel retinoic acid response element in the promoter

    SciTech Connect

    Zou Fang; Liu Yan; Liu Li; Wu Kailang; Wei Wei; Zhu Ying . E-mail: yingzhu@whu.edu.cn; Wu Jianguo . E-mail: wu9988@vip.sina.com

    2007-04-06

    Human inducible nitric oxide synthase (hiNOS) catalyzes nitric oxide (NO) which has a significant effect on tumor suppression and cancer therapy. Here we revealed the detailed molecular mechanism involved in the regulation of hiNOS expression induced by retinoic acid (RA). We showed that RAR{alpha}/RXR{alpha} heterodimer was important in hiNOS promoter activation, hiNOS protein expression, and NO production. Serial deletion and site-directed mutation analysis revealed two half-sites of retinoic acid response element (RARE) spaced by 5 bp located at -172 to -156 in the hiNOS promoter. EMSA and ChIP assays demonstrated that RAR{alpha}/RXR{alpha} directly bound to this RARE of hiNOS promoter. Our results suggested the identification of a novel RARE in the hiNOS promoter and the roles of the nuclear receptors (RAR{alpha}/RXR{alpha}) in the induction of hiNOS by RA.

  12. Immune response, productivity and quality of milk from grazing goats as affected by dietary polyunsaturated fatty acid supplementation.

    PubMed

    Caroprese, Mariangela; Ciliberti, Maria Giovana; Santillo, Antonella; Marino, Rosaria; Sevi, Agostino; Albenzio, Marzia

    2016-04-01

    This study was undertaken to assess how diet supplemented with fish oil and linseed improve the immune profile, the production performance, and milk quality of grazing goats by a diet supplementation of fish oil or linseed. Twenty-four Garganica grazing goats were divided into three groups named control (CON), fish oil (FO) and linseed (LIN) according to the fat supplement received in their diet. In vivo immune responses were evaluated by monitoring cell-mediated and humoral immune responses in order to verify the effects of polyunsaturated fatty acids supplementation on goats' health status. Goat milk samples were analysed weekly to determine milk chemical composition, fatty acid profile, and somatic cell count. Diet based on linseed supplementation (LIN) significantly increased milk yield by 30%, milk fat yield by 67%, protein yield by 34%, and casein yield by 41% as compared with CON. Fat content increased by 30% in LIN milk as compared with CON milk, and by 12% as compared with FO milk. Linseed modified milk fatty acid profile; LIN milk showed lower SFA and higher PUFA than FO milk. The modified fatty acid composition of LIN milk resulted in lower AI and TI indexes than FO and CON milk. Linseed and fish oil administration can reduce humoral immunity of goats, but has no effect in their cellular immunity. Dietary linseed supplementation in grazing dairy goat supports feeding programs to improve milk composition and quality, and a modulation of their immune responses. PMID:27033938

  13. Formulation of pH responsive peptides as inhalable dry powders for pulmonary delivery of nucleic acids

    PubMed Central

    Liang, Wanling; Kwok, Philip C.L.; Chow, Michael Y.T.; Tang, Patricia; Mason, A. James; Chan, Hak-Kim; Lam, Jenny. K.W.

    2013-01-01

    Nucleic acids have the potential to be used as therapies or vaccines for many different types of disease but delivery remains the most significant challenge to their clinical adoption. pH responsive peptides containing either histidine or derivatives of 2,3-diaminopropionic acid (Dap) can mediate effective DNA transfection in lung epithelial cells with the latter remaining effective even in the presence of lung surfactant containing bronchoalveolar fluid (BALF), making this class of peptides attractive candidates for delivering nucleic acids to lung tissues. To further assess the suitability of pH responsive peptides for pulmonary delivery by inhalation, dry powder formulations of pH responsive peptides and plasmid DNA, with mannitol as carrier, were produced by either spray drying (SD) or spray freeze drying (SFD). The properties of the two types of powders were characterised and compared using scanning electron microscopy (SEM), next generation impaction (NGI), gel retardation and in vitro transfection via a twin-stage impinger (TSI) following aerosolisation by a dry powder inhaler (Osmohaler™). Although the aerodynamic performance and transfection efficacy of both powders were good, the overall performance revealed SD powders to have a number of advantages over SFD powders and are the more effective formulation with potential for efficient nucleic acid delivery through inhalation. PMID:23702276

  14. Nonspecific bronchial responsiveness assessed in vitro following acute inhalation exposure to ozone and ozone/sulfuric acid mixtures

    SciTech Connect

    El-Fawal, H.A.N.; McGovern, T.; Schlesinger, R.B.

    1995-01-01

    Air pollution may play some role in the recent increase in severity and prevalence of asthma, but the specific chemical components with the ambient pollutant mix that may be responsible have not been delineated. Since ambient exposures involve mixtures, it is essential to examine airway responses to realistic pollutant mixtures. This study examined the ability of single (3-h) inhalation exposures to ozone and to mixtures of ozone plus sulfuric acid to induce nonspecific airway hyperresponsiveness in healthy rabbits. Airway responsiveness was assessed using an in vitro assay involving administration of increasing doses of acetylcholine to bronchial rings obtained from animals exposed to 0.1-0.6 ppm ozone or to mixtures of ozone and 50-125 {mu}g/m{sup 3} sulfuric acid aerosol; results were compared to those reported previously for sulfuric acid alone. Bronchial hyperresponsiveness in healthy animals and suggest that interaction with sulfuric acid may reduce the effectiveness of both pollutants. 31 refs., 3 figs., 3 tabs.

  15. Efficient nuclear drug translocation and improved drug efficacy mediated by acidity-responsive boronate-linked dextran/cholesterol nanoassembly.

    PubMed

    Zhu, Jing-Yi; Lei, Qi; Yang, Bin; Jia, Hui-Zhen; Qiu, Wen-Xiu; Wang, Xuli; Zeng, Xuan; Zhuo, Ren-Xi; Feng, Jun; Zhang, Xian-Zheng

    2015-06-01

    The present study reported a lysosome-acidity-targeting bio-responsive nanovehicle self-assembled from dextran (Dex) and phenylboronic acid modified cholesterol (Chol-PBA), aiming at the nucleus-tropic drug delivery. The prominent advantage of this assembled nanoconstruction arose from its susceptibility to acidity-labile dissociation concurrently accompanied with the fast liberation of encapsulated drugs, leading to efficient nuclear drug translocation and consequently favorable drug efficacy. By elaborately exploiting NH4Cl pretreatment to interfere with the cellular endosomal acidification progression, this study clearly evidenced at a cellular level the strong lysosomal-acidity dependency of nuclear drug uptake efficiency, which was shown to be the main factor influencing the drug efficacy. The boronate-linked nanoassembly displayed nearly no cytotoxicity and can remain structural stability under the simulated physiological conditions including 10% serum and the normal blood sugar concentration. The cellular exposure to cholesterol was found to bate the cellular uptake of nanoassembly in a dose-dependent manner, suggesting a cholesterol-associated mechanism of the intracellular internalization. The in vivo antitumor assessment in xenograft mouse models revealed the significant superiority of DOX-loaded Dex/Chol-PBA nanoassembly over the controls including free DOX and the DOX-loaded non-sensitive Dex-Chol, as reflected by the more effective tumor-growth inhibition and the better systematic safety. In terms of the convenient preparation, sensitive response to lysosomal acidity and efficient nuclear drug translocation, Dex/Chol-PBA nanoassembly derived from natural materials shows promising potentials as the nanovehicle for nucleus-tropic drug delivery especially for antitumor agents. More attractively, this study offers a deeper insight into the mechanism concerning the contribution of acidity-responsive delivery to the enhanced chemotherapy performance. PMID

  16. Alpine re-activation of pre-Alpine structures: details from a large-scale shear zone in the Aar massif (Central Alps)

    NASA Astrophysics Data System (ADS)

    Wehrens, Philip; Baumberger, Roland; Herwegh, Marco

    2013-04-01

    The Aar massif belongs to the external massifs of the Alps and is mainly composed of granitoids and gneisses. Post-Variscan granitoid rocks have intruded old gneisses belonging to the pre-Variscan basement. Despite numerous detailed studies in the past decades, the overall exhumation history and the associated massif internal deformation (internal strain distribution and its evolution in time, kinematics etc.) are largely unknown at present. In this project, we aim to investigate the role of shear zones in the deformation history at a variety of scales. In this context it is important to understand their microstructural evolution, the involved deformation processes, kinematics and relative ages as well as the associated changes in rheology. A detailed study was conducted along a major shear zone located at the southern margin of the Aar massif (running from Furka to Grimsel Pass and Oberaar Glacier), where the Grimsel Granodiorite (GrGr) is juxtapositioned to strongly foliated gneisses. Preliminary results show that a crenulation of these gneisses predates the age of the granitoid intrusion, meaning they must be older than 298 Ma. The crenulation and a related axial plane foliation (145/80°) define mechanical anisotropies within these Pre-Variscan rocks. The intruding granite has exploited these anisotropies a first time during its emplacement in post-Variscan times. The lithological boundary between the intruded GrGr and Pre-Variscan rocks causes strain again to localize during Alpine deformation and results in a 40 m wide large-scale shear zone. The older part of the shear zone shows cm-scale shear zones with vertical lineations shearing off the aforementioned pre-Alpine axial plane foliation. Hence the contact is reactivated, now as Alpine normal/ reverse fault, a second time. Towards the youngest parts of the shear zone the stretching lineation on the shear surfaces turns from vertical towards a subhorizontal position, indicating a change from initial vertical

  17. Growth responses of breast and leg muscles to essential amino acids in broiler chicks.

    PubMed

    Mehri, M; Bagherzadeh-Kasmani, F; Rokouei, M

    2016-03-01

    The first three essential amino acids (EAA) for broilers including methionine (Met), lysine (Lys) and threonine (Thr) may greatly influence the growth of chick muscles at early stages of life. In order to survey the potential effects of those EAA on growth muscles, a rotatable three-variable central composite design (CCD) was conducted to track the interrelationships of dietary digestible Met (dMet), Lys (dLys) and Thr (dThr) for optimization of processing yields in broiler chicks using response surface methodology. A total of 60 floor pens of six birds each were assigned to 15 dietary treatments based on CCD containing five levels of dMet (0.416% to 0.584% of diet), dLys (0.881% to 1.319% of diet) and dThr (0.532% to 0.868% of diet) from 3 to 16 days of age. Experimental treatments significantly affected breast mass (BM) and leg mass (LM) of the birds (P<0.05) in which the main effect of dLys on BM was threefold higher than the main effect of dThr, and interaction effect between dMet and dLys was observed on BM (P<0.05). However, in the case of LM, the main effect of dThr was higher than the main effects of dMet and dLys and highest interaction effect exist between dThr and dMet (P<0.05). The second-order models for BM and LM were fitted by least squares regression. Canonical analysis revealed that the stationary points for carcass components were saddle points, thus ridge analysis was performed for getting optimal values of each EAA. Ridge analyses of BM and LM models showed that the maximum BM point may be obtained with 0.58%, 1.05% and 0.76% of dMet, dLys and dThr, respectively, in diet, and maximum LM point may be achieved with 0.58%, 1.09% and 0.70% of dMet, dLys and dThr, respectively, in diet. The resultant ideal ratios of dMet and dThr to dLys were 55% and 72% for BM; 53% and 64% for LM. Moreover, sensitivity analysis showed that the most important amino acids in BM and LM models were Lys and Thr, respectively. In conclusion, providing these three amino

  18. Jasmonic Acid, Abscisic Acid, and Salicylic Acid Are Involved in the Phytoalexin Responses of Rice to Fusarium fujikuroi, a High Gibberellin Producer Pathogen.

    PubMed

    Siciliano, Ilenia; Amaral Carneiro, Greice; Spadaro, Davide; Garibaldi, Angelo; Gullino, Maria Lodovica

    2015-09-23

    Fusarium fujikuroi, the causal agent of bakanae disease, is the main seedborne pathogen on rice. To understand the basis of rice resistance, a quantitative method to simultaneously detect phytohormones and phytoalexins was developed by using HPLC-MS/MS. With this method dynamic profiles and possible interactions of defense-related phytohormones and phytoalexins were investigated on two rice cultivars, inoculated or not with F. fujikuroi. In the resistant cultivar Selenio, the presence of pathogen induced high production of phytoalexins, mainly sakuranetin, and symptoms of bakanae were not observed. On the contrary, in the susceptible genotype Dorella, the pathogen induced the production of gibberellin and abscisic acid and inhibited jasmonic acid production, phytoalexins were very low, and bakanae symptoms were observed. The results suggested that a wide range of secondary metabolites are involved in plant defense against pathogens and phytoalexin synthesis could be an important factor for rice resistance against bakanae disease. PMID:26323788

  19. Bacteria-triggered systemic immunity in barley is associated with WRKY and ETHYLENE RESPONSIVE FACTORs but not with salicylic acid.

    PubMed

    Dey, Sanjukta; Wenig, Marion; Langen, Gregor; Sharma, Sapna; Kugler, Karl G; Knappe, Claudia; Hause, Bettina; Bichlmeier, Marlies; Babaeizad, Valiollah; Imani, Jafargholi; Janzik, Ingar; Stempfl, Thomas; Hückelhoven, Ralph; Kogel, Karl-Heinz; Mayer, Klaus F X; Vlot, A Corina

    2014-12-01

    Leaf-to-leaf systemic immune signaling known as systemic acquired resistance is poorly understood in monocotyledonous plants. Here, we characterize systemic immunity in barley (Hordeum vulgare) triggered after primary leaf infection with either Pseudomonas syringae pathovar japonica (Psj) or Xanthomonas translucens pathovar cerealis (Xtc). Both pathogens induced resistance in systemic, uninfected leaves against a subsequent challenge infection with Xtc. In contrast to systemic acquired resistance in Arabidopsis (Arabidopsis thaliana), systemic immunity in barley was not associated with NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 or the local or systemic accumulation of salicylic acid. Instead, we documented a moderate local but not systemic induction of abscisic acid after infection of leaves with Psj. In contrast to salicylic acid or its functional analog benzothiadiazole, local applications of the jasmonic acid methyl ester or abscisic acid triggered systemic immunity to Xtc. RNA sequencing analysis of local and systemic transcript accumulation revealed unique gene expression changes in response to both Psj and Xtc and a clear separation of local from systemic responses. The systemic response appeared relatively modest, and quantitative reverse transcription-polymerase chain reaction associated systemic immunity with the local and systemic induction of two WRKY and two ETHYLENE RESPONSIVE FACTOR (ERF)-like transcription factors. Systemic immunity against Xtc was further associated with transcriptional changes after a secondary/systemic Xtc challenge infection; these changes were dependent on the primary treatment. Taken together, bacteria-induced systemic immunity in barley may be mediated in part by WRKY and ERF-like transcription factors, possibly facilitating transcriptional reprogramming to potentiate immunity. PMID:25332505

  20. Molecular Targets of Omega 3 and Conjugated Linoleic Fatty Acids – “Micromanaging” Cellular Response

    PubMed Central

    Visioli, Francesco; Giordano, Elena; Nicod, Nathalie Marie; Dávalos, Alberto

    2012-01-01

    Essential fatty acids cannot be synthesized de novo by mammals and need to be ingested either with the diet or through the use of supplements/functional foods to ameliorate cardiovascular prognosis. This review focus on the molecular targets of omega 3 fatty acids and conjugated linoleic acid, as paradigmatic molecules that can be exploited both as nutrients and as pharmacological agents, especially as related to cardioprotection. In addition, we indicate novel molecular targets, namely microRNAs that might contribute to the observed biological activities of such essential fatty acids. PMID:22393325

  1. Osteoblast response to the surface of amino acid-functionalized hydroxyapatite.

    PubMed

    Lee, Wing-Hin; Loo, Ching-Yee; Chrzanowski, Wojciech; Rohanizadeh, Ramin

    2015-06-01

    Interactions between proteins and the surface of biomaterials are crucial for the biological function and success of materials implanted in the human body. In this study, hydroxyapatite (HA) with negative and positive surface charges were fabricated by functionalizing the HA surface with acidic or basic amino acids. The influence of HA surface charge on protein adsorption and cell activities was studied. The crystallinity, morphology, and surface charge of amino acid-functionalized HA (AA-HA) particles and the stability of amino acids on the HA surface were determined. Both AA-HA and unmodified HA were studied for their capacity to adsorb proteins present in biological medium. The results showed that the presence of glutamic acid; Glu (acidic amino acids) and arginine; Arg (basic amino acids) on the HA surface resulted in higher protein adsorption owing to stronger electrostatic attraction between the HA particles and the proteins in medium. Functionalizing HA with Glu and Arg significantly promoted osteoblast adhesion on the surface of treated HA. No significant differences in cell proliferation between negatively and positively charged HA was observed. Significantly higher alkaline phosphatase (ALP) activity of osteoblasts on both charged surfaces was seen as compared to the unmodified HA. The study demonstrated that immobilization of amino acids (Glu and Arg) on the surface of HA promoted osteoblast proliferation and ALP activity. PMID:25346517

  2. Transcriptomic Analysis of Escherichia coli O157:H7 and K-12 Cultures Exposed to Inorganic and Organic Acids in Stationary Phase Reveals Acidulant- and Strain-Specific Acid Tolerance Responses ▿ †

    PubMed Central

    King, Thea; Lucchini, Sacha; Hinton, Jay C. D.; Gobius, Kari

    2010-01-01

    The food-borne pathogen Escherichia coli O157:H7 is commonly exposed to organic acid in processed and preserved foods, allowing adaptation and the development of tolerance to pH levels otherwise lethal. Since little is known about the molecular basis of adaptation of E. coli to organic acids, we studied K-12 MG1655 and O157:H7 Sakai during exposure to acetic, lactic, and hydrochloric acid at pH 5.5. This is the first analysis of the pH-dependent transcriptomic response of stationary-phase E. coli. Thirty-four genes and three intergenic regions were upregulated by both strains during exposure to all acids. This universal acid response included genes involved in oxidative, envelope, and cold stress resistance and iron and manganese uptake, as well as 10 genes of unknown function. Acidulant- and strain-specific responses were also revealed. The acidulant-specific response reflects differences in the modes of microbial inactivation, even between weak organic acids. The two strains exhibited similar responses to lactic and hydrochloric acid, while the response to acetic acid was distinct. Acidulant-dependent differences between the strains involved induction of genes involved in the heat shock response, osmoregulation, inorganic ion and nucleotide transport and metabolism, translation, and energy production. E. coli O157:H7-specific acid-inducible genes were identified, suggesting that the enterohemorrhagic E. coli strain possesses additional molecular mechanisms contributing to acid resistance that are absent in K-12. While E. coli K-12 was most resistant to lactic and hydrochloric acid, O157:H7 may have a greater ability to survive in more complex acidic environments, such as those encountered in the host and during food processing. PMID:20709847

  3. Repression by ARP-1 sensitizes apolipoprotein AI gene responsiveness to RXR alpha and retinoic acid.

    PubMed Central

    Widom, R L; Rhee, M; Karathanasis, S K

    1992-01-01

    The gene coding for apolipoprotein AI (apoAI), a lipid binding protein involved in the transport of cholesterol and other lipids in the plasma, is expressed in mammals predominantly in the liver and the intestine. Liver-specific expression is controlled by synergistic interactions between transcription factors bound to three separate sites, sites A (-214 to -192), B (-169 to -146), and C (-134 to -119), within a powerful liver-specific enhancer located between nucleotides -222 and -110 upstream of the apoAI gene transcription start site (+1). Previous studies in our laboratory have shown that ARP-1, a member of the nuclear receptor superfamily whose ligand is unknown (orphan receptor), binds to site A and represses transcription of the apoAI gene in liver cells. In a more recent series of experiments, we found that site A is a retinoic acid (RA) response element that responds preferentially to the recently identified RA-responsive receptor RXR alpha over the previously characterized RA receptors RAR alpha and RAR beta. In this study we investigated the combined effects of ARP-1 and RXR alpha on apoAI gene expression in liver cells. Transient transfection assays showed that site A is necessary and sufficient for RXR alpha-mediated transactivation of the apoAI gene basal promoter in human hepatoma HepG2 cells in the presence of RA and that this transactivation is abolished by increasing amounts of cotransfected ARP-1. Electrophoretic mobility shift assays and subsequent Scatchard analysis of the data revealed that ARP-1 and RXR alpha bind to site A with similar affinities. These assays also revealed that ARP-1 and RXR alpha bind to site A as heterodimers with an affinity approximately 10 times greater than that of either ARP-1 or RXR alpha alone. Further transfection assays in HepG2 cells, using as a reporter a construct containing the apoAI gene basal promoter and its upstream regulatory elements (including site A) in their natural context, revealed that RXR alpha

  4. AV3V lesions attenuate the cardiovascular responses produced by blood-borne excitatory amino acid analogs

    NASA Technical Reports Server (NTRS)

    Whalen, E. J.; Beltz, T. G.; Lewis, S. J.; Johnson, A. K.

    1999-01-01

    Systemic injections of the excitatory amino acid (EAA) analogs, kainic acid (KA) and N-methyl-D-aspartate (NMDA), produce a pressor response in conscious rats that is caused by a centrally mediated activation of sympathetic drive and the release of arginine vasopressin (AVP). This study tested the hypothesis that the tissue surrounding the anteroventral part of the third ventricle (AV3V) plays a role in the expression of the pressor responses produced by systemically injected EAA analogs. Specifically, we examined whether prior electrolytic ablation of the AV3V region would affect the pressor responses to KA and NMDA (1 mg/kg iv) in conscious rats. The KA-induced pressor response was smaller in AV3V-lesioned than in sham-lesioned rats (11 +/- 2 vs. 29 +/- 2 mmHg; P < 0.05). After ganglion blockade, KA produced a pressor response in sham-lesioned but not AV3V-lesioned rats (+27 +/- 3 vs. +1 +/- 2 mmHg; P < 0.05). The KA-induced pressor response in ganglion-blocked sham-lesioned rats was abolished by a vasopressin V1-receptor antagonist. Similar results were obtained with NMDA. The pressor response to AVP (10 ng/kg iv) was slightly smaller in AV3V-lesioned than in sham-lesioned ganglion-blocked rats (45 +/- 3 vs. 57 +/- 4 mmHg; P < 0.05). This study demonstrates that the pressor responses to systemically injected EAA analogs are smaller in AV3V-lesioned rats. The EAA analogs may produce pressor responses by stimulation of EAA receptors in the AV3V region, or the AV3V region may play an important role in the expression of these responses.

  5. Arsenite and monomethylarsonous acid generate oxidative stress response in human bladder cell culture

    SciTech Connect

    Eblin, K.E. . E-mail: eblin@pharmacy.arizona.edu; Bowen, M.E.; Cromey, D.W.; Bredfeldt, T.G.; Mash, E.A.; Lau, S.S.; Gandolfi, A.J.

    2006-11-15

    Arsenicals have commonly been seen to induce reactive oxygen species (ROS) which can lead to DNA damage and oxidative stress. At low levels, arsenicals still induce the formation of ROS, leading to DNA damage and protein alterations. UROtsa cells, an immortalized human urothelial cell line, were used to study the effects of arsenicals on the human bladder, a site of arsenical bioconcentration and carcinogenesis. Biotransformation of As(III) by UROtsa cells has been shown to produce methylated species, namely monomethylarsonous acid [MMA(III)], which has been shown to be 20 times more cytotoxic. Confocal fluorescence images of UROtsa cells treated with arsenicals and the ROS sensing probe, DCFDA, showed an increase of intracellular ROS within five min after 1 {mu}M and 10 {mu}M As(III) treatments. In contrast, 50 and 500 nM MMA(III) required pretreatment for 30 min before inducing ROS. The increase in ROS was ameliorated by preincubation with either SOD or catalase. An interesting aspect of these ROS detection studies is the noticeable difference between concentrations of As(III) and MMA(III) used, further supporting the increased cytotoxicity of MMA(III), as well as the increased amount of time required for MMA(III) to cause oxidative stress. These arsenical-induced ROS produced oxidative DNA damage as evidenced by an increase in 8-hydroxyl-2'-deoxyguanosine (8-oxo-dG) with either 50 nM or 5 {mu}M MMA(III) exposure. These findings provide support that MMA(III) cause a genotoxic response upon generation of ROS. Both As(III) and MMA(III) were also able to induce Hsp70 and MT protein levels above control, showing that the cells recognize the ROS and respond. As(III) rapidly induces the formation of ROS, possibly through it oxidation to As(V) and further metabolism to MMA(III)/(V). These studies provide evidence for a different mechanism of MMA(III) toxicity, one that MMA(III) first interacts with cellular components before an ROS response is generated, taking longer

  6. Resistant and susceptible responses in tomato to cyst nematode are differentially regulated by salicylic acid.

    PubMed

    Uehara, Taketo; Sugiyama, Shunpei; Matsuura, Hideyuki; Arie, Tsutomu; Masuta, Chikara

    2010-09-01

    To understand the machinery underlying a tomato cultivar harboring the Hero A gene against cyst nematode using microarrays, we first analyzed tomato gene expression in response to potato cyst nematode (PCN; Globodera rostochiensis) during the early incompatible and compatible interactions at 3 and 7 days post-inoculation (dpi). Transcript levels of the phenylalanine ammonia lyase (PAL) and Myb-related genes were up-regulated at 3 dpi in the incompatible interaction. Transcription of the genes encoding pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) was also up-regulated at 3 dpi in the incompatible interaction. On the other hand, the four genes (PAL, Myb, PDC and ADH) were down-regulated in the compatible interaction at 3 dpi. When the expression levels of several pathogenesis-related (PR) protein genes in tomato roots were compared between the incompatible and compatible interactions, the salicylic acid (SA)-dependent PR genes were found to be induced in the incompatible interaction at 3 dpi. The PR-1(P4) transcript increased to an exceptionally high level at 3 dpi in the cyst nematode-infected resistant plants compared with the uninoculated controls. The free SA levels were elevated to similar levels in both incompatible and compatible interactions. We then confirmed that PR-1(P4) was not significantly induced in the NahG tomato harboring the Hero A gene, compared with the resistant cultivar. We thus found that PR-1(P4) was a hallmark for the cultivar resistance conferred by Hero A against PCN and that nematode parasitism resulted in the inhibition of the SA signaling pathway in the susceptible cultivars. PMID:20660227

  7. Salicylic acid induces differential antioxidant response in spring maize under high temperature stress.

    PubMed

    Khanna, Palak; Kaur, Kamaljit; Gupta, Anil K

    2016-06-01

    High temperature is one of the important stress factors that affect crops in tropical countries. Plants do evolve or adopt different mechanisms to overcome such stress for survival. It is an interesting subject and has attracted many researchers to work upon. Here, we studied the effect of salicylic acid (SA) on seedling growth and antioxidative defense system in two spring maize (Zea mays L.) genotypes viz., CML-32 (relatively heat tolerant) and LM-11 (relatively heat susceptible), under high temperature stress. High temperature induced greater reduction in dry biomass of LM-1 1 seedlings as compared to those of CML-32. There was a parallel increase in ascorbate peroxidase and glutathione reductase activities in the roots of CML-32 seedlings. However, the activities of catalase and superoxide dismutase decreased and the contents of H202, proline and malonaldialdehyde (MDA) increased in seedlings of both the genotypes. Application of SA (400 µM) led to increased dry biomass in heat stressed CML-32 seedlings. It improved the efficiency of Halliwell-Asada pathway in roots of CML-32 seedlings as was evidenced by the enhanced ascorbate peroxidase and glutathione reductase activities. The activities of catalase and superoxide dismutase increased in both the tissues of LM-11 seedlings, whereas in CML-32, it was only in shoots, after SA application. Peroxidase activity increased in SA treated seedlings of both the genotypes, though the increase was comparatively higher in CML-32. The contents of H₂O₂ and MDA decreased and that of proline increased in SA treated seedlings of both the genotypes, under stress conditions. It may be concluded that SA induced differential antioxidant response by upregulating Halliwell-Asada pathway in roots and attaining high POX activity in both the tissues of CML-32 seedlings, under high temperature stress. PMID:27468465

  8. Subgroup Variations in Bone Mineral Density Response to Zoledronic Acid After Hip Fracture

    PubMed Central

    Magaziner, Jay S; Orwig, Denise L; Lyles, Kenneth W; Nordsletten, Lars; Boonen, Steven; Adachi, Jonathan D; Recknor, Chris; Colón-Emeric, Cathleen S; Mesenbrink, Peter; Bucci-Rechtweg, Christina; Su, Guoqin; Johnson, Rasheeda; Pieper, Carl F

    2014-01-01

    Minimizing post-fracture bone loss is an important aspect of recovery from hip fracture, and determination of factors that affect bone mineral density (BMD) response to treatment after hip fracture may assist in the development of targeted therapeutic interventions. A post hoc analysis of the HORIZON Recurrent Fracture Trial was done to determine the effect of zoledronic acid (ZOL) on total hip (TH) and femoral neck (FN) BMD in subgroups with low-trauma hip fracture. A total of 2127 patients were randomized (1:1) to yearly infusions of ZOL 5 mg (n = 1065) or placebo (n = 1062) within 90 days of operation for low-trauma hip fracture. The 1486 patients with a baseline and at least one post-baseline BMD assessment at TH or FN (ZOL = 745, placebo = 741) were included in the analyses. Percentage change from baseline in TH and FN BMD was assessed at months 12 and 24 and compared across subgroups of hip fracture patients. Percentage change from baseline in TH and FN BMD at months 12 and 24 was greater (p < 0.05) in ZOL-treated patients compared with placebo in most subgroups. Treatment-by-subgroup interactions (p < 0.05) indicated that a greater effect on BMD was observed for TH BMD at month 12 in females, in patients in the lower tertile body mass index at baseline (≤22.6 kg/m2), and in patients with baseline FN BMD T-score of ≤ –2.5; for FN BMD in patients who received ZOL for >6 weeks post-surgery; and for TH and FN BMD in patients with a history of one or more prior fractures. All interactions were limited to the first 12 months after treatment with none observed for the 24-month comparisons. (Clinical trial registration number NCT00046254.) PMID:24839241

  9. Soil solution response to experimentally reduced acid deposition in a forest ecosystem

    SciTech Connect

    Alewell, C.; Matzner, E.; Bredemeier, M.; Blanch, K.

    1997-05-01

    In order to measure and predict reversibility of soil solution acidification under experimentally reduced acid input, a manipulation study with artificial {open_quote}preindustrial{close_quote} throughfall was established. A roof was installed underneath the canopy in a Norway Spruce stand of the German Soiling area. Water failing onto the roof was adjusted to clean rain concentrations before redistribution. Soil solutions were collected with suction cup lysimeters at various depths and were analyzed for major ions. The response of soil solution chemistry in the upper soil (10 cm depth) to a reduction of N, SO{sub 4}, and H input was rapid. While NO{sub 3} concentration in deeper soil layers reached input levels after 2 yr of treatment, SO{sub 4} concentration in the seepage water at 1 m depth remained high relative to the reduced input due to a release of formerly stored S from the soil. Aluminum concentration followed a similar pattern as the SO{sub 4} concentrations. The ion concentrations in soil leachate were predicted reasonably well using the MAGIC model with the measured SO{sub 4} sorption isotherms and the throughfall fluxes as model input Although the parameters of the Langmuir isotherm had no significant influence to the prediction of SO{sub 4} concentration in the upper soil layer, they were crucial for the prediction of SO{sub 4} dynamics in deeper soil layers. The model predicted that the reversibility of soil acidification at the Soiling area is delayed for decades due to the release of soil SO{sub 4}. 38 refs., 5 figs., 4 tabs.

  10. An Ancestral Role for CONSTITUTIVE TRIPLE RESPONSE1 Proteins in Both Ethylene and Abscisic Acid Signaling.

    PubMed

    Yasumura, Yuki; Pierik, Ronald; Kelly, Steven; Sakuta, Masaaki; Voesenek, Laurentius A C J; Harberd, Nicholas P

    2015-09-01

    Land plants have evolved adaptive regulatory mechanisms enabling the survival of environmental stresses associated with terrestrial life. Here, we focus on the evolution of the regulatory CONSTITUTIVE TRIPLE RESPONSE1 (CTR1) component of the ethylene signaling pathway that modulates stress-related changes in plant growth and development. First, we compare CTR1-like proteins from a bryophyte, Physcomitrella patens (representative of early divergent land plants), with those of more recently diverged lycophyte and angiosperm species (including Arabidopsis [Arabidopsis thaliana]) and identify a monophyletic CTR1 family. The fully sequenced P. patens genome encodes only a single member of this family (PpCTR1L). Next, we compare the functions of PpCTR1L with that of related angiosperm proteins. We show that, like angiosperm CTR1 proteins (e.g. AtCTR1 of Arabidopsis), PpCTR1L modulates downstream ethylene signaling via direct interaction with ethylene receptors. These functions, therefore, likely predate the divergence of the bryophytes from the land-plant lineage. However, we also show that PpCTR1L unexpectedly has dual functions and additionally modulates abscisic acid (ABA) signaling. In contrast, while AtCTR1 lacks detectable ABA signaling functions, Arabidopsis has during evolution acquired another homolog that is functionally distinct from AtCTR1. In conclusion, the roles of CTR1-related proteins appear to have functionally diversified during land-plant evolution, and angiosperm CTR1-related proteins appear to have lost an ancestral ABA signaling function. Our study provides new insights into how molecular events such as gene duplication and functional differentiation may have contributed to the adaptive evolution of regulatory mechanisms in plants. PMID:26243614

  11. Actinobacillus succinogenes ATCC 55618 Fermentation Medium Optimization for the Production of Succinic Acid by Response Surface Methodology

    PubMed Central

    Zhu, Li-Wen; Wang, Cheng-Cheng; Liu, Rui-Sang; Li, Hong-Mei; Wan, Duan-Ji; Tang, Ya-Jie

    2012-01-01

    As a potential intermediary feedstock, succinic acid takes an important place in bulk chemical productions. For the first time, a method combining Plackett-Burman design (PBD), steepest ascent method (SA), and Box-Behnken design (BBD) was developed to optimize Actinobacillus succinogenes ATCC 55618 fermentation medium. First, glucose, yeast extract, and MgCO3 were identified to be key medium components by PBD. Second, preliminary optimization was run by SA method to access the optimal region of the key medium components. Finally, the responses, that is, the production of succinic acid, were optimized simultaneously by using BBD, and the optimal concentration was located to be 84.6 g L−1 of glucose, 14.5 g L−1 of yeast extract, and 64.7 g L−1 of MgCO3. Verification experiment indicated that the maximal succinic acid production of 52.7 ± 0.8 g L−1 was obtained under the identified optimal conditions. The result agreed with the predicted value well. Compared with that of the basic medium, the production of succinic acid and yield of succinic acid against glucose were enhanced by 67.3% and 111.1%, respectively. The results obtained in this study may be useful for the industrial commercial production of succinic acid. PMID:23093852

  12. Benzoic Acid Production with Respect to Starter Culture and Incubation Temperature during Yogurt Fermentation using Response Surface Methodology

    PubMed Central

    Yoo, Mi-Young; Lim, Sang-Dong

    2016-01-01

    Benzoic acid is occasionally used as a raw material supplement in food products and is sometimes generated during the fermentation process. In this study, the production of naturally occurring yogurt preservatives was investigated for various starter cultures and incubation temperatures, and considered food regulations. Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus reuteri, Lactobacillus plantarum, Bifidobacterium longum, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium infantis, and Bifidobacterium breve were used as yogurt starter cultures in commercial starters. Among these strains, L. rhamnosus and L. paracasei showed the highest production of benzoic acid. Therefore, the use of L. rhamnosus, L. paracasei, S. thermophilus, and different incubation temperatures were examined to optimize benzoic acid production. Response surface methodology (RSM) based on a central composite design was performed for various incubation temperatures (35-44℃) and starter culture inoculum ratios (0-0.04%) in a commercial range of dairy fermentation processes. The optimum conditions were 0.04% L. rhamnosus, 0.01% L. paracasei, 0.02% S. thermophilus, and 38.12℃, and the predicted and estimated concentrations of benzoic acid were 13.31 and 13.94 mg/kg, respectively. These conditions maximized naturally occurring benzoic acid production during the yogurt fermentation process, and the observed production levels satisfied regulatory guidelines for benzoic acid in dairy products. PMID:27433115

  13. Benzoic Acid Production with Respect to Starter Culture and Incubation Temperature during Yogurt Fermentation using Response Surface Methodology.

    PubMed

    Yu, Hyung-Seok; Lee, Na-Kyoung; Jeon, Hye-Lin; Eom, Su Jin; Yoo, Mi-Young; Lim, Sang-Dong; Paik, Hyun-Dong

    2016-01-01

    Benzoic acid is occasionally used as a raw material supplement in food products and is sometimes generated during the fermentation process. In this study, the production of naturally occurring yogurt preservatives was investigated for various starter cultures and incubation temperatures, and considered food regulations. Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus reuteri, Lactobacillus plantarum, Bifidobacterium longum, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium infantis, and Bifidobacterium breve were used as yogurt starter cultures in commercial starters. Among these strains, L. rhamnosus and L. paracasei showed the highest production of benzoic acid. Therefore, the use of L. rhamnosus, L. paracasei, S. thermophilus, and different incubation temperatures were examined to optimize benzoic acid production. Response surface methodology (RSM) based on a central composite design was performed for various incubation temperatures (35-44℃) and starter culture inoculum ratios (0-0.04%) in a commercial range of dairy fermentation processes. The optimum conditions were 0.04% L. rhamnosus, 0.01% L. paracasei, 0.02% S. thermophilus, and 38.12℃, and the predicted and estimated concentrations of benzoic acid were 13.31 and 13.94 mg/kg, respectively. These conditions maximized naturally occurring benzoic acid production during the yogurt fermentation process, and the observed production levels satisfied regulatory guidelines for benzoic acid in dairy products. PMID:27433115

  14. Actinobacillus succinogenes ATCC 55618 fermentation medium optimization for the production of succinic acid by response surface methodology.

    PubMed

    Zhu, Li-Wen; Wang, Cheng-Cheng; Liu, Rui-Sang; Li, Hong-Mei; Wan, Duan-Ji; Tang, Ya-Jie

    2012-01-01

    As a potential intermediary feedstock, succinic acid takes an important place in bulk chemical productions. For the first time, a method combining Plackett-Burman design (PBD), steepest ascent method (SA), and Box-Behnken design (BBD) was developed to optimize Actinobacillus succinogenes ATCC 55618 fermentation medium. First, glucose, yeast extract, and MgCO(3) were identified to be key medium components by PBD. Second, preliminary optimization was run by SA method to access the optimal region of the key medium components. Finally, the responses, that is, the production of succinic acid, were optimized simultaneously by using BBD, and the optimal concentration was located to be 84.6 g L(-1) of glucose, 14.5 g L(-1) of yeast extract, and 64.7 g L(-1) of MgCO(3). Verification experiment indicated that the maximal succinic acid production of 52.7 ± 0.8 g L(-1) was obtained under the identified optimal conditions. The result agreed with the predicted value well. Compared with that of the basic medium, the production of succinic acid and yield of succinic acid against glucose were enhanced by 67.3% and 111.1%, respectively. The results obtained in this study may be useful for the industrial commercial production of succinic acid. PMID:23093852

  15. SuperSAGE analysis of the Nicotiana attenuata transcriptome after fatty acid-amino acid elicitation (FAC): identification of early mediators of insect responses

    PubMed Central

    2010-01-01

    Background Plants trigger and tailor defense responses after perception of the oral secretions (OS) of attacking specialist lepidopteran larvae. Fatty acid-amino acid conjugates (FACs) in the OS of the Manduca sexta larvae are necessary and sufficient to elicit the herbivory-specific responses in Nicotiana attenuata, an annual wild tobacco species. How FACs are perceived and activate signal transduction mechanisms is unknown. Results We used SuperSAGE combined with 454 sequencing to quantify the early transcriptional changes elicited by the FAC N-linolenoyl-glutamic acid (18:3-Glu) and virus induced gene silencing (VIGS) to examine the function of candidate genes in the M. sexta-N. attenuata interaction. The analysis targeted mRNAs encoding regulatory components: rare transcripts with very rapid FAC-elicited kinetics (increases within 60 and declines within 120 min). From 12,744 unique Tag sequences identified (UniTags), 430 and 117 were significantly up- and down-regulated ≥ 2.5-fold, respectively, after 18:3-Glu elicitation compared to wounding. Based on gene ontology classification, more than 25% of the annotated UniTags corresponded to putative regulatory components, including 30 transcriptional regulators and 22 protein kinases. Quantitative PCR analysis was used to analyze the FAC-dependent regulation of a subset of 27 of these UniTags and for most of them a rapid and transient induction was confirmed. Six FAC-regulated genes were functionally characterized by VIGS and two, a putative lipid phosphate phosphatase (LPP) and a protein of unknown function, were identified as important mediators of the M. sexta-N. attenuata interaction. Conclusions The analysis of the early changes in the transcriptome of N. attenuata after FAC elicitation using SuperSAGE/454 has identified regulatory genes involved in insect-specific mediated responses in plants. Moreover, it has provided a foundation for the identification of additional novel regulators associated with this

  16. Enhanced anticancer potency using an acid-responsive ZnO-incorporated liposomal drug-delivery system.

    PubMed

    Tripathy, Nirmalya; Ahmad, Rafiq; Ko, Hyun Ah; Khang, Gilson; Hahn, Yoon-Bong

    2015-03-01

    The development of stimuli-responsive nanocarriers is becoming important in chemotherapy. Liposomes, with an appropriate triggering mechanism, can efficiently deliver their encapsulated cargo in a controlled manner. We explored the use of acid-sensitive zinc oxide nanoparticles (ZNPs) as modulators of the responsive properties of liposomes. Nanocomplexes formed by the incorporation of ZNPs in liposomes (ZNP-liposomes) were designed to demonstrate the pH-responsive release of a drug (daunorubicin) without premature drug leakage and with the maintenance of the relevant therapeutic concentrations. The nanocomplexes were spherical in shape with a narrow size distribution and showed a high drug-encapsulating efficiency. Under acidic conditions, the ZNP-liposome nanocomplexes released the loaded drug more rapidly than bare liposomes. Using flow cytometry, confocal microscopy and an MTT assay, we demonstrated that these nanocomplexes were readily taken up by cancer cells, resulting in significantly enhanced cytotoxicity. On exposure to the acidic conditions inside cancer cells, the ZNPs rapidly decomposed, releasing the entrapped drug molecules from the ZNP-liposome nanocomplexes, producing widespread cytotoxic effects. The incorporated ZNPs were multimodal in that they not only resulted in a pH-responsive drug-delivery system, but they also had a synergistic chemo-photodynamic anticancer action. This design provides a significant step towards the development of multimodal liposome structures. PMID:25660501

  17. Phosphate Starvation Responses and Gibberellic Acid Biosynthesis Are Regulated by the MYB62 Transcription Factor in Arabidopsis

    PubMed Central

    Devaiah, Ballachanda N.; Madhuvanthi, Ramaiah; Karthikeyan, Athikkattuvalasu S.; Raghothama, Kashchandra G.

    2009-01-01

    The limited availability of phosphate (Pi) in most soils results in the manifestation of Pi starvation responses in plants. To dissect the transcriptional regulation of Pi stress-response mechanisms, we have characterized the biological role of MYB62, an R2R3-type MYB transcription factor that is induced in response to Pi deficiency. The induction of MYB62 is a specific response in the leaves during Pi deprivation. The MYB62 protein localizes to the nucleus. The overexpression of MYB62 resulted in altered root architecture, Pi uptake, and acid phosphatase activity, leading to decreased total Pi content in the shoots. The expression of several Pi starvation-induced (PSI) genes was also suppressed in the MYB62 overexpressing plants. Overexpression of MYB62 resulted in a characteristic gibberellic acid (GA)-deficient phenotype that could be partially reversed by exogenous application of GA. In addition, the expression of SOC1 and SUPERMAN, molecular regulators of flowering, was suppressed in the MYB62 overexpressing plants. Interestingly, the expression of these genes was also reduced during Pi deprivation in wild-type plants, suggesting a role for GA biosynthetic and floral regulatory genes in Pi starvation responses. Thus, this study highlights the role of MYB62 in the regulation of phosphate starvation responses via changes in GA metabolism and signaling. Such cross-talk between Pi homeostasis and GA might have broader implications on flowering, root development and adaptive mechanisms during nutrient stress. PMID:19529828

  18. Biochemical Response to Ursodeoxycholic Acid Predicts Survival in a North American Cohort of Primary Biliary Cirrhosis Patients

    PubMed Central

    Lammert, Craig; Juran, Brian D.; Schlicht, Erik; Chan, Landon L.; Atkinson, Elizabeth J.; de Andrade, Mariza; Lazaridis, Konstantinos N.

    2014-01-01

    Background Biochemical response to Ursodeoxycholic Acid among patients with Primary Biliary Cirrhosis remains variable and there is no agreement of an ideal model. Novel assessment of response coupled to histologic progression was recently defined by the Toronto criteria. We retrospectively assessed transplant-free survival and clinical outcomes associated with Ursodeoxycholic Acid response to evaluate the Toronto criteria using a large North American cohort of PBC patients. Methods 398 PBC patients from the Mayo Clinic PBC Genetic Epidemiology (MCPGE) Registry were assessed for Ursodeoxycholic Acid treatment and biochemical response per the Toronto criteria. Responders were defined by reduction in alkaline phosphatase to less than or equal to 1.67 times the upper normal limit by 2 years of treatment, whereas non-responders had alkaline phosphatase values greater than 1.67 times the upper normal limit. Probability of survival was estimated using the Kaplan-Meier method. Results 302 (76%) patients were responders and 96 (24%) were non-responders. Significantly more non-responders developed adverse events related to chronic liver disease compared to responders (Hazard Ratio (HR): 2.77, P = 0.001). Biochemical responders and early-stage disease at treatment start was associated with improved overall transplant-free survival compared to non-responders (HR: 1.9) and patients with late stage disease (HR: 2.7) after age and sex adjustment. Conclusions The Toronto criteria are capable of identifying Ursodeoxycholic Acid-treated Primary Biliary Cirrhosis patients at risk of poor transplant-free survival and adverse clinical outcomes. Our data reveal that despite advanced disease at diagnosis, biochemical response per the Toronto criteria associates with improved overall transplant-free survival. PMID:24317935

  19. Role and regulation of fatty acid biosynthesis in the response of Shewanella piezotolerans WP3 to different temperatures and pressures.

    PubMed

    Wang, Feng; Xiao, Xiang; Ou, Hong-Yu; Gai, Yingbao; Wang, Fengping

    2009-04-01

    Members of the genus Shewanella inhabit various environments; they are capable of synthesizing various types of low-melting-point fatty acids, including monounsaturated fatty acids (MUFA) and branched-chain fatty acids (BCFA) with and without eicosapentanoic acid (EPA). The genes involved in fatty acid synthesis in 15 whole-genome-sequenced Shewanella strains were identified and compared. A typical type II fatty acid synthesis pathway in Shewanella was constructed. A complete EPA synthesis gene cluster was found in all of the Shewanella genomes, although only a few of them were found to produce EPA. The roles and regulation of fatty acids synthesis in Shewanella were further elucidated in the Shewanella piezotolerans WP3 response to different temperatures and pressures. The EPA and BCFA contents of WP3 significantly increased when it was grown at low temperature and/or under high pressure. EPA, but not MUFA, was determined to be crucial for its growth at low temperature and high pressure. A gene cluster for a branched-chain amino acid ABC transporter (LIV-I) was found to be upregulated at low temperature. Combined approaches, including mutagenesis and an isotopic-tracer method, revealed that the LIV-I transporter played an important role in the regulation of BCFA synthesis in WP3. The LIV-I transporter was identified only in the cold-adapted Shewanella species and was assumed to supply an important strategy for Shewanella cold adaptation. This is the first time the molecular mechanism of BCFA regulation in bacteria has been elucidated. PMID:19201790

  20. Upregulation of early growth response factor-1 by bile acids requires mitogen-activated protein kinase signaling

    SciTech Connect

    Allen, Katryn; Kim, Nam Deuk; Moon, Jeon-OK; Copple, Bryan L.

    2010-02-15

    Cholestasis results when excretion of bile acids from the liver is interrupted. Liver injury occurs during cholestasis, and recent studies showed that inflammation is required for injury. Our previous studies demonstrated that early growth response factor-1 (Egr-1) is required for development of inflammation in liver during cholestasis, and that bile acids upregulate Egr-1 in hepatocytes. What remains unclear is the mechanism by which bile acids upregulate Egr-1. Bile acids modulate gene expression in hepatocytes by activating the farnesoid X receptor (FXR) and through activation of mitogen-activated protein kinase (MAPK) signaling. Accordingly, the hypothesis was tested that bile acids upregulate Egr-1 in hepatocytes by FXR and/or MAPK-dependent mechanisms. Deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA) stimulated upregulation of Egr-1 to the same extent in hepatocytes isolated from wild-type mice and FXR knockout mice. Similarly, upregulation of Egr-1 in the livers of bile duct-ligated (BDL) wild-type and FXR knockout mice was not different. Upregulation of Egr-1 in hepatocytes by DCA and CDCA was prevented by the MEK inhibitors U0126 and SL-327. Furthermore, pretreatment of mice with U0126 prevented upregulation of Egr-1 in the liver after BDL. Results from these studies demonstrate that activation of MAPK signaling is required for upregulation of Egr-1 by bile acids in hepatocytes and for upregulation of Egr-1 in the liver during cholestasis. These studies suggest that inhibition of MAPK signaling may be a novel therapy to prevent upregulation of Egr-1 in liver during cholestasis.

  1. In vitro fatty acid enrichment of macrophages alters inflammatory response and net cholesterol accumulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dietary omega (omega)-3 polyunsaturated fatty acids (PUFA) and omega–6 PUFA are thought to have unique benefits with respect to cardiovascular disease. Macrophages (M phi) differentiated from human monocytic cell line THP-1 were used to assess the effect of omega-3 PUFA (eicosapentaenoic acid [EPA]...

  2. Arabidopsis GUX Proteins Are Glucuronyltransferases Responsible for the Addition of Glucuronic Acid Side Chains onto Xylan

    EPA Science Inventory

    Xylan, the second most abundant cell wall polysaccharide, is composed of a linear backbone of β-(1,4)-linked xylosyl residues that are often substituted with sugar side chains, such as glucuronic acid (GlcA) and methylglucuronic acid (MeGlcA). It has recently been shown that muta...

  3. Immune-responsive gene 1 protein links metabolism to immunity by catalyzing itaconic acid production.

    PubMed

    Michelucci, Alessandro; Cordes, Thekla; Ghelfi, Jenny; Pailot, Arnaud; Reiling, Norbert; Goldmann, Oliver; Binz, Tina; Wegner, André; Tallam, Aravind; Rausell, Antonio; Buttini, Manuel; Linster, Carole L; Medina, Eva; Balling, Rudi; Hiller, Karsten

    2013-05-01

    Immunoresponsive gene 1 (Irg1) is highly expressed in mammalian macrophages during inflammation, but its biological function has not yet been elucidated. Here, we identify Irg1 as the gene coding for an enzyme producing itaconic acid (also known as methylenesuccinic acid) through the decarboxylation of cis-aconitate, a tricarboxylic acid cycle intermediate. Using a gain-and-loss-of-function approach in both mouse and human immune cells, we found Irg1 expression levels correlating with the amounts of itaconic acid, a metabolite previously proposed to have an antimicrobial effect. We purified IRG1 protein and identified its cis-aconitate decarboxylating activity in an enzymatic assay. Itaconic acid is an organic compound that inhibits isocitrate lyase, the key enzyme of the glyoxylate shunt, a pathway essential for bacterial growth under specific conditions. Here we show that itaconic acid inhibits the growth of bacteria expressing isocitrate lyase, such as Salmonella enterica and Mycobacterium tuberculosis. Furthermore, Irg1 gene silencing in macrophages resulted in significantly decreased intracellular itaconic acid levels as well as significantly reduced antimicrobial activity during bacterial infections. Taken together, our results demonstrate that IRG1 links cellular metabolism with immune defense by catalyzing itaconic acid production. PMID:23610393

  4. Immune-responsive gene 1 protein links metabolism to immunity by catalyzing itaconic acid production

    PubMed Central

    Michelucci, Alessandro; Cordes, Thekla; Ghelfi, Jenny; Pailot, Arnaud; Reiling, Norbert; Goldmann, Oliver; Binz, Tina; Wegner, André; Tallam, Aravind; Rausell, Antonio; Buttini, Manuel; Linster, Carole L.; Medina, Eva; Balling, Rudi; Hiller, Karsten

    2013-01-01

    Immunoresponsive gene 1 (Irg1) is highly expressed in mammalian macrophages during inflammation, but its biological function has not yet been elucidated. Here, we identify Irg1 as the gene coding for an enzyme producing itaconic acid (also known as methylenesuccinic acid) through the decarboxylation of cis-aconitate, a tricarboxylic acid cycle intermediate. Using a gain-and-loss-of-function approach in both mouse and human immune cells, we found Irg1 expression levels correlating with the amounts of itaconic acid, a metabolite previously proposed to have an antimicrobial effect. We purified IRG1 protein and identified its cis-aconitate decarboxylating activity in an enzymatic assay. Itaconic acid is an organic compound that inhibits isocitrate lyase, the key enzyme of the glyoxylate shunt, a pathway essential for bacterial growth under specific conditions. Here we show that itaconic acid inhibits the growth of bacteria expressing isocitrate lyase, such as Salmonella enterica and Mycobacterium tuberculosis. Furthermore, Irg1 gene silencing in macrophages resulted in significantly decreased intracellular itaconic acid levels as well as significantly reduced antimicrobial activity during bacterial infections. Taken together, our results demonstrate that IRG1 links cellular metabolism with immune defense by catalyzing itaconic acid production. PMID:23610393

  5. Response of plasma membrane H+-ATPase in rice (Oryza sativa) seedlings to simulated acid rain.

    PubMed

    Liang, Chanjuan; Ge, Yuqing; Su, Lei; Bu, Jinjin

    2015-01-01

    Understanding the adaptation of plants to acid rain is important to find feasible approaches to alleviate such damage to plants. We studied effects of acid rain on plasma membrane H(+)-ATPase activity and transcription, intracellular H(+), membrane permeability, photosynthetic efficiency, and relative growth rate during stress and recovery periods. Simulated acid rain at pH 5.5 did not affect plasma membrane H(+)-ATPase activity, intracellular H(+), membrane permeability, photosynthetic efficiency, and relative growth rate. Plasma membrane H(+)-ATPase activity and transcription in leaves treated with acid rain at pH 3.5 was increased to maintain ion homeostasis by transporting excessive H(+) out of cells. Then intracellular H(+) was close to the control after a 5-day recovery, alleviating damage on membrane and sustaining photosynthetic efficiency and growth. Simulated acid rain at pH 2.5 inhibited plasma membrane H(+)-ATPase activity by decreasing the expression of H(+)-ATPase at transcription level, resulting in membrane damage and abnormal intracellular H(+), and reduction in photosynthetic efficiency and relative growth rate. After a 5-day recovery, all parameters in leaves treated with pH 2.5 acid rain show alleviated damage, implying that the increased plasma membrane H(+)-ATPase activity and its high expression were involved in repairing process in acid rain-stressed plants. Our study suggests that plasma membrane H(+)-ATPase can play a role in adaptation to acid rain for rice seedlings. PMID:25087500

  6. EFFECTS OF SIMULATED ACID RAIN ON YIELD RESPONSE OF TWO SOYBEAN CULTIVARS

    EPA Science Inventory

    An important component of the effects of acid rain on our ecosystem is its impact on the yield of agricultural crops. ield experiments were conducted for 3 yr to determine the effects of simulated acid rain on seed yield of two soybean [Glycine max (L.) Merr.] cultivars. 'Amsoy 7...

  7. Response of plasma fatty acid profiles to changes in dietary n-3 fatty acids and its correlation with erythrocyte fatty acid profiles in dogs.

    PubMed

    Stoeckel, K; Bachmann, L; Dobeleit, G; Fuhrmann, H

    2013-12-01

    An elevated level of long-chain n-3 fatty acids (FA) in tissue membranes has a positive influence on the progression and treatment of many diseases. Therefore, dietary supplementation of n-3 FA is recommended in some diseases. Even though n-3 FA are absorbed readily from the diet, their incorporation into tissues may be compromised in diseased animals. In a clinical setting, it is desirable to monitor the success of dietary intervention. Plasma FA as well as erythrocyte membrane (EM) FA can be used to monitor dietary FA intake. This study compares FA from EM and plasma with regard to their reaction time and reliability for monitoring dietary changes of tissue FA profiles in dogs. Thirty dogs were divided into three groups and fed for 12 weeks. The control group (CONT) was fed a commercial standard diet low in n-3 FA. One group received the standard diet and 85 mg/kg body weight of a docosahexaenoic acid (DHA) concentrate (ADD). The third group was fed a commercial dog food containing fish oil (FO), which is rich in eicosapentaenoic acid (EPA). EM and plasma FA profiles were analysed by GC separately. Data on EM FA were published recently. n-3 FA in plasma reached the new level after 2 weeks (8 weeks in EM). Dietary differences between DHA and EPA are obvious after 1 week already. The concomitant decrease in plasma n-6 FA differed between ADD and FO. In general, the correlation of n-6 FA between plasma and EM was low. We therefore conclude that analysis of plasma FA is sufficient for monitoring a diet-induced increase in tissue n-3 FA in dogs. However, EM FA should be analysed if the effect of dietary intervention on tissue n-6 FA is important. PMID:23279610

  8. Thermoregulatory and cardiovascular responses to creatine, glycerol and alpha lipoic acid in trained cyclists

    PubMed Central

    2012-01-01

    Background It has been shown that supplementation with creatine (Cr) and glycerol (Gly), when combined with glucose (Glu) necessary for the enhancement of Cr uptake by skeletal muscle, induces significant improvements in thermoregulatory and cardiovascular responses during exercise in the heat. Purpose To determine whether Cr/Gly-induced thermoregulatory and cardiovascular responses are maintained when the majority (~75%) of the Glu in the Cr/Gly supplement is replaced with the insulintropic agent alpha lipoic acid (Ala). Methods 22 healthy endurance trained cyclists were randomly assigned to receive either 20 g/day (4 × 5 g/day) of Cr, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly and 150 g/day (4 × 37.5 g/day) of Glu or 20 g/day (4 × 5 g/day) of Cr monohydrate, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly (100 g/day (4 × 25 g/day) of Glu and 1000 mg/day (4 × 250 mg/day) of Ala for 7 days for 7 days. Exercise trials were conducted pre- and post-supplementation and involved 40 min of constant-load cycling exercise at 70% O2 max by a self-paced 16.1 km time trial at 30°C and 70% relative humidity. Results Median and range values of TBW increased significantly by 2.1 (1.3-3.3) L and 1.8 (0.2-4.6) L in Cr/Gly/Glu and Cr/Gly/Glu/Ala groups respectively (P = 0.03) and of BM not significantly by 1.8 (0.2-3.0) kg and 1.2 (0.5-2.1) kg in Cr/Gly/Glu and in Cr/Gly/Glu/Ala, respectively (P = 0.75). During constant load exercise, heart rate (HR) and core temperature (Tcore) were significantly lower post-supplementation: HR was reduced on average by 3.3 ± 2.1 beats/min and by 4.8 ± 3.3 beats/min (mean ± SD) and Tcore by 0.2 ± 0.1 (mean ± SD) in the Cr/Gly/Glu and Cr/Gly/Glu/Ala, respectively The reduction in HR and Tcore was not significantly different between the supplementation groups. Conclusions In comparison to the established hyper hydrating Cr

  9. Growth of exfoliation joints and near-surface stress orientations inferred from fractographic markings observed in the upper Aar valley (Swiss Alps)

    NASA Astrophysics Data System (ADS)

    Ziegler, Martin; Loew, Simon; Bahat, Dov

    2014-06-01

    Granitic rock mass of the upper Aar valley (Grimsel area, Switzerland) contains distinct generations of exfoliation joints, which formed during different stages of the Pleistocene, subparallel to distinct glacial valley palaeotopography. The bulk of exfoliation joints shows prominent, common fractographic features: (1) radial plumose structures with distinct plume axes; (2) arrest marks superimposed by plumose striations; and (3) gradually-developing en échelon fringe cracks. Multiple arrest marks reveal that exfoliation joints formed incrementally and, together with the absence of hackle fringes, suggest stable, i.e., subcritical fracturing conditions. Smooth transitions from plumose structures on the parent plane to en échelon fringe cracks, combined with non-systematic stepping senses of fringe cracks, suggest local (vs. temporal) stress field variations. Assuming that plume axes formed parallel to the maximum principal compressive stress (σ1) enables us to infer near-surface palaeostress orientations and compare them with classical borehole-based in-situ stress data. The majority of plume axes suggest (1) persistently subhorizontal to slightly inclined σ1 orientations at trough valley slopes and (2) near-surface variability of σ1 orientations originating from topographic perturbation caused by glacial valley erosion superimposed on the regional stress field. Our investigations of fracture surface morphologies yield unique insights into exfoliation fracture formation, such as directional trends of fracture propagation and associated palaeostress orientations within Alpine valley slopes.

  10. Laser photobioactivation mechanisms: In vitro studies using ascorbic acid uptake and hydroxyproline formation as biochemical markers of irradiation response

    SciTech Connect

    Labbe, R.F.; Skogerboe, K.J.; Davis, H.A.; Rettmer, R.L. )

    1990-01-01

    Clinical investigations of laser photobioactivation, or biostimulation, might be differently designed and more fruitful if knowledge of basic biochemical mechanisms were better understood. In this investigation, biochemical events identified as responses to 904 nm irradiation included increased ascorbic acid uptake by fibroblasts. These cells also showed increased hydroxyproline formation, and this was increased several-fold by the addition of proline to the medium. Maximum biochemical responses were observed at a pulse frequency of 67 Hz and a pulse width of 150 nsec with an energy density of approximately 7 mJ/cm2 per exposure. Elements in the mitochondrial cytochrome system are proposed as the radiation absorbing chromophore(s). Hypothetically, the energy generated is linked to ascorbic acid uptake, which in turn stimulates collagen synthesis.

  11. Plasmodium falciparum Malaria Elicits Inflammatory Responses that Dysregulate Placental Amino Acid Transport

    PubMed Central

    Boeuf, Philippe; Aitken, Elizabeth H.; Chandrasiri, Upeksha; Chua, Caroline Lin Lin; McInerney, Bernie; McQuade, Leon; Duffy, Michael; Molyneux, Malcolm; Brown, Graham; Glazier, Jocelyn; Rogerson, Stephen J.

    2013-01-01

    Placental malaria (PM) can lead to poor neonatal outcomes, including low birthweight due to fetal growth restriction (FGR), especially when associated with local inflammation (intervillositis or IV). The pathogenesis of PM-associated FGR is largely unknown, but in idiopathic FGR, impaired transplacental amino acid transport, especially through the system A group of amino acid transporters, has been implicated. We hypothesized that PM-associated FGR could result from impairment of transplacental amino acid transport triggered by IV. In a cohort of Malawian women and their infants, the expression and activity of system A (measured by Na+-dependent 14C-MeAIB uptake) were reduced in PM, especially when associated with IV, compared to uninfected placentas. In an in vitro model of PM with IV, placental cells exposed to monocyte/infected erythrocytes conditioned medium showed decreased system A activity. Amino acid concentrations analyzed by reversed phase ultra performance liquid chromatography in paired maternal and cord plasmas revealed specific alterations of amino acid transport by PM, especially with IV. Overall, our data suggest that the fetoplacental unit responds to PM by altering its placental amino acid transport to maintain adequate fetal growth. However, IV more profoundly compromises placental amino acid transport function, leading to FGR. Our study offers the first pathogenetic explanation for FGR in PM. PMID:23408887

  12. Houttuyniae Herba Attenuates Kainic Acid-Induced Neurotoxicity via Calcium Response Modulation in the Mouse Hippocampus.

    PubMed

    Kim, Hyo Geun; Jeong, Hyun Uk; Hong, Sung In; Oh, Myung Sook

    2015-12-01

    Epilepsy is a complex neurological disorder characterized by the repeated occurrence of electrical activity known as seizures. This activity induces increased intracellular calcium, which ultimately leads to neuronal damage. Houttuyniae Herba, the aerial part of Houttuynia cordata, has various pharmacological effects and is widely used as a traditional herb. In the present study, we evaluated the protective effects of Houttuyniae Herba water extract on kainic acid-induced neurotoxicity. Kainic acid directly acts on calcium release, resulting in seizure behavior, neuronal damage, and cognitive impairment. In a rat primary hippocampal culture system, Houttuyniae Herba water extract significantly protected neuronal cells from kainic acid toxicity. In a seizure model where mice received intracerebellar kainic acid injections, Houttuyniae Herba water extract treatment resulted in a lower seizure stage score, ameliorated cognitive impairment, protected neuronal cells against kainic acid-induced toxicity, and suppressed neuronal degeneration in the hippocampus. In addition, Houttuyniae Herba water extract regulated increases in the intracellular calcium level, its related downstream pathways (reactive oxygen species production and mitochondrial dysfunction), and calcium/calmodulin complex kinase type II immunoreactivity in the mouse hippocampus, which resulted from calcium influx stimulation induced by kainic acid. These results demonstrate the neuroprotective effects of Houttuyniae Herba water extract through inhibition of calcium generation in a kainic acid-induced epileptic model. PMID:26366753

  13. Decoding genome-wide GadEWX-transcriptional regulatory networks reveals multifaceted cellular responses to acid stress in Escherichia coli.

    PubMed

    Seo, Sang Woo; Kim, Donghyuk; O'Brien, Edward J; Szubin, Richard; Palsson, Bernhard O

    2015-01-01

    The regulators GadE, GadW and GadX (which we refer to as GadEWX) play a critical role in the transcriptional regulation of the glutamate-dependent acid resistance (GDAR) system in Escherichia coli K-12 MG1655. However, the genome-wide regulatory role of GadEWX is still unknown. Here we comprehensively reconstruct the genome-wide GadEWX transcriptional regulatory network and RpoS involvement in E. coli K-12 MG1655 under acidic stress. Integrative data analysis reveals that GadEWX regulons consist of 45 genes in 31 transcription units and 28 of these genes were associated with RpoS-binding sites. We demonstrate that GadEWX directly and coherently regulate several proton-generating/consuming enzymes with pairs of negative-feedback loops for pH homeostasis. In addition, GadEWX regulate genes with assorted functions, including molecular chaperones, acid resistance, stress response and other regulatory activities. These results show how GadEWX simultaneously coordinate many cellular processes to produce the overall response of E. coli to acid stress. PMID:26258987

  14. Decoding genome-wide GadEWX-transcriptional regulatory networks reveals multifaceted cellular responses to acid stress in Escherichia coli

    PubMed Central

    Seo, Sang Woo; Kim, Donghyuk; O'Brien, Edward J.; Szubin, Richard; Palsson, Bernhard O.

    2015-01-01

    The regulators GadE, GadW and GadX (which we refer to as GadEWX) play a critical role in the transcriptional regulation of the glutamate-dependent acid resistance (GDAR) system in Escherichia coli K-12 MG1655. However, the genome-wide regulatory role of GadEWX is still unknown. Here we comprehensively reconstruct the genome-wide GadEWX transcriptional regulatory network and RpoS involvement in E. coli K-12 MG1655 under acidic stress. Integrative data analysis reveals that GadEWX regulons consist of 45 genes in 31 transcription units and 28 of these genes were associated with RpoS-binding sites. We demonstrate that GadEWX directly and coherently regulate several proton-generating/consuming enzymes with pairs of negative-feedback loops for pH homeostasis. In addition, GadEWX regulate genes with assorted functions, including molecular chaperones, acid resistance, stress response and other regulatory activities. These results show how GadEWX simultaneously coordinate many cellular processes to produce the overall response of E. coli to acid stress. PMID:26258987

  15. Comparative response of lead-acid and nickel/iron batteries to pulsed and constant-current loads

    SciTech Connect

    DeLuca, W.H.; Tummillo, A.F.; Biwer, T.L.; Christianson, C.C.; Hornstra, F.; Yao, N.P.

    1983-01-01

    Improved lead-acid and nickel/iron batteries are currently being developed for use in electric vehicles. The response of these batteries to given discharge conditions differs due to the inherent characteristics of each system. The discharge capacity of the lead-acid system is reduced (>25%) at increased discharge rates and its internal resistance is a function of both depth-of-discharge (DOD) and discharge rate. However, open-circuit stand times (0.5 to 2.0 h) at DOD levels >50% reduce the internal resistance of the lead-acid system and provide a corresponding increase in its availability capacity. In comparison, the discharge capacity and internal resistance of the nickel/iron system are virtually independent of both discharge rate and open-circuit stand times during discharge. With pulsed-current loads, the available energy and power output of both battery systems are always less than those obtained with equivalent constant-current loads due to increased internal power losses. The nickel/iron system exhibits an internal inductance that is significantly greater than that for the lead-acid system thereby causing potentially damaging voltage transients. This paper describes the test procedures and system employed, presents the test data, and methods for predicting battery response, and discusses the results obtained.

  16. Ultrasound-assisted extraction of pectins from grape pomace using citric acid: a response surface methodology approach.

    PubMed

    Minjares-Fuentes, R; Femenia, A; Garau, M C; Meza-Velázquez, J A; Simal, S; Rosselló, C

    2014-06-15

    An ultrasound-assisted procedure for the extraction of pectins from grape pomace with citric acid as the extracting agent was established. A Box-Behnken design (BBD) was employed to optimize the extraction temperature (X1: 35-75°C), extraction time (X2: 20-60 min) and pH (X3: 1.0-2.0) to obtain a high yield of pectins with high average molecular weight (MW) and degree of esterification (DE) from grape pomace. Analysis of variance showed that the contribution of a quadratic model was significant for the pectin extraction yield and for pectin MW whereas the DE of pectins was more influenced by a linear model. An optimization study using response surface methodology was performed and 3D response surfaces were plotted from the mathematical model. According to the RSM model, the highest pectin yield (∼32.3%) can be achieved when the UAE process is carried out at 75°C for 60 min using a citric acid solution of pH 2.0. These pectic polysaccharides, composed mainly by galacturonic acid units (<97% of total sugars), have an average MW of 163.9 kDa and a DE of 55.2%. Close agreement between experimental and predicted values was found. These results suggest that ultrasound-assisted extraction could be a good option for the extraction of functional pectins with citric acid from grape pomace at industrial level. PMID:24721067

  17. Arabidopsis MYC Transcription Factors Are the Target of Hormonal Salicylic Acid/Jasmonic Acid Cross Talk in Response to Pieris brassicae Egg Extract.

    PubMed

    Schmiesing, André; Emonet, Aurélia; Gouhier-Darimont, Caroline; Reymond, Philippe

    2016-04-01

    Arabidopsis (Arabidopsis thaliana) plants recognize insect eggs and activate the salicylic acid (SA) pathway. As a consequence, expression of defense genes regulated by the jasmonic acid (JA) pathway is suppressed and larval performance is enhanced. Cross talk between defense signaling pathways is common in plant-pathogen interactions, but the molecular mechanism mediating this phenomenon is poorly understood. Here, we demonstrate that egg-induced SA/JA antagonism works independently of the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factor ORA59, which controls the ERF branch of the JA pathway. In addition, treatment with egg extract did not enhance expression or stability of JASMONATE ZIM-domain transcriptional repressors, and SA/JA cross talk did not involve JASMONATE ASSOCIATED MYC2-LIKEs, which are negative regulators of the JA pathway. Investigating the stability of MYC2, MYC3, and MYC4, three basic helix-loop-helix transcription factors that additively control jasmonate-related defense responses, we found that egg extract treatment strongly diminished MYC protein levels in an SA-dependent manner. Furthermore, we identified WRKY75 as a novel and essential factor controlling SA/JA cross talk. These data indicate that insect eggs target the MYC branch of the JA pathway and uncover an unexpected modulation of SA/JA antagonism depending on the biological context in which the SA pathway is activated. PMID:26884488

  18. Arabidopsis MYC Transcription Factors Are the Target of Hormonal Salicylic Acid/Jasmonic Acid Cross Talk in Response to Pieris brassicae Egg Extract1[OPEN

    PubMed Central

    Schmiesing, André; Gouhier-Darimont, Caroline

    2016-01-01

    Arabidopsis (Arabidopsis thaliana) plants recognize insect eggs and activate the salicylic acid (SA) pathway. As a consequence, expression of defense genes regulated by the jasmonic acid (JA) pathway is suppressed and larval performance is enhanced. Cross talk between defense signaling pathways is common in plant-pathogen interactions, but the molecular mechanism mediating this phenomenon is poorly understood. Here, we demonstrate that egg-induced SA/JA antagonism works independently of the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factor ORA59, which controls the ERF branch of the JA pathway. In addition, treatment with egg extract did not enhance expression or stability of JASMONATE ZIM-domain transcriptional repressors, and SA/JA cross talk did not involve JASMONATE ASSOCIATED MYC2-LIKEs, which are negative regulators of the JA pathway. Investigating the stability of MYC2, MYC3, and MYC4, three basic helix-loop-helix transcription factors that additively control jasmonate-related defense responses, we found that egg extract treatment strongly diminished MYC protein levels in an SA-dependent manner. Furthermore, we identified WRKY75 as a novel and essential factor controlling SA/JA cross talk. These data indicate that insect eggs target the MYC branch of the JA pathway and uncover an unexpected modulation of SA/JA antagonism depending on the biological context in which the SA pathway is activated. PMID:26884488

  19. Determinants of Erythrocyte Omega‐3 Fatty Acid Content in Response to Fish Oil Supplementation: A Dose–Response Randomized Controlled Trial

    PubMed Central

    Flock, Michael R.; Skulas‐Ray, Ann C.; Harris, William S.; Etherton, Terry D.; Fleming, Jennifer A.; Kris‐Etherton, Penny M.

    2013-01-01

    Background The erythrocyte membrane content of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which constitutes the omega‐3 index (O3I), predicts cardiovascular disease mortality. The amount of EPA+DHA needed to achieve a target O3I is poorly defined, as are the determinants of the O3I response to a change in EPA+DHA intake. The objective of this study was to develop a predictive model of the O3I response to EPA+DHA supplementation in healthy adults, specifically identifying factors that determine the response. Methods and Results A randomized, placebo‐controlled, double‐blind, parallel‐group study was conducted in 115 healthy men and women. One of 5 doses (0, 300, 600, 900, 1800 mg) of EPA+DHA was given daily as placebo or fish oil supplements for ≈5 months. The O3I was measured at baseline and at the end of the study. There were no significant differences in the clinical characteristics between the groups at baseline. The O3I increased in a dose‐dependent manner (P<0.0001), with the dose of EPA+DHA alone accounting for 68% (quadratic, P<0.0001) of the variability in the O3I response. Dose adjusted per unit body weight (g/kg) accounted for 70% (linear, P<0.0001). Additional factors that improved prediction of treatment response were baseline O3I, age, sex, and physical activity. Collectively, these explained 78% of the response variability (P<0.0001). Conclusions Our findings validate the O3I as a biomarker of EPA+DHA consumption and identify additional factors, particularly body weight, that can be used to tailor EPA+DHA recommendations to achieve a target O3I. PMID:24252845

  20. Plants Know Where It Hurts: Root and Shoot Jasmonic Acid Induction Elicit Differential Responses in Brassica oleracea

    PubMed Central

    Tytgat, Tom O.G.; Verhoeven, Koen J. F.; Jansen, Jeroen J.; Raaijmakers, Ciska E.; Bakx-Schotman, Tanja; McIntyre, Lauren M.; van der Putten, Wim H.; Biere, Arjen; van Dam, Nicole M.

    2013-01-01

    Plants respond to herbivore attack by rapidly inducing defenses that are mainly regulated by jasmonic acid (JA). Due to the systemic nature of induced defenses, attack by root herbivores can also result in a shoot response and vice versa, causing interactions between above- and belowground herbivores. However, little is known about the molecular mechanisms underlying these interactions. We investigated whether plants respond differently when roots or shoots are induced. We mimicked herbivore attack by applying JA to the roots or shoots of Brassica oleracea and analyzed molecular and chemical responses in both organs. In shoots, an immediate and massive change in primary and secondary metabolism was observed. In roots, the JA-induced response was less extensive and qualitatively different from that in the shoots. Strikingly, in both roots and shoots we also observed differential responses in primary metabolism, development as well as defense specific traits depending on whether the JA induction had been below- or aboveground. We conclude that the JA response is not only tissue-specific but also dependent on the organ that was induced. Already very early in the JA signaling pathway the differential response was observed. This indicates that both organs have a different JA signaling cascade, and that the signal eliciting systemic responses contains information about the site of induction, thus providing plants with a mechanism to tailor their responses specifically to the organ that is damaged. PMID:23776489

  1. Dose-response effect of elevated plasma free fatty acid on insulin signaling.

    PubMed

    Belfort, Renata; Mandarino, Lawrence; Kashyap, Sangeeta; Wirfel, Kelly; Pratipanawatr, Thongchai; Berria, Rachele; Defronzo, Ralph A; Cusi, Kenneth

    2005-06-01

    The dose-response relationship between elevated plasma free fatty acid (FFA) levels and impaired insulin-mediated glucose disposal and insulin signaling was examined in 21 lean, healthy, normal glucose-tolerant subjects. Following a 4-h saline or Liposyn infusion at 30 (n = 9), 60 (n = 6), and 90 (n = 6) ml/h, subjects received a 2-h euglycemic insulin (40 mU . m(-2) . min(-1)) clamp. Basal plasma FFA concentration ( approximately 440 micromol/l) was increased to 695, 1,251, and 1,688 micromol/l after 4 h of Liposyn infusion and resulted in a dose-dependent reduction in insulin-stimulated glucose disposal (R(d)) by 22, 30, and 34%, respectively (all P < 0.05 vs. saline control). At the lowest lipid infusion rate (30 ml/h), insulin receptor and insulin receptor substrate (IRS)-1 tyrosine phosphorylation, phosphatidylinositol (PI) 3-kinase activity associated with IRS-1, and Akt serine phosphorylation were all significantly impaired (P < 0.05-0.01). The highest lipid infusion rate (90 ml/h) caused a further significant reduction in all insulin signaling events compared with the low-dose lipid infusion (P < 0.05-0.01) whereas the 60-ml/h lipid infusion caused an intermediate reduction in insulin signaling. However, about two-thirds of the maximal inhibition of insulin-stimulated glucose disposal already occurred at the rather modest increase in plasma FFA induced by the low-dose (30-ml/h) lipid infusion. Insulin-stimulated glucose disposal was inversely correlated with both the plasma FFA concentration after 4 h of lipid infusion (r = -0.50, P = 0.001) and the plasma FFA level during the last 30 min of the insulin clamp (r = -0.54, P < 0.001). PI 3-kinase activity associated with IRS-1 correlated with insulin-stimulated glucose disposal (r = 0.45, P < 0.01) and inversely with both the plasma FFA concentration after 4 h of lipid infusion (r = -0.39, P = 0.01) and during the last 30 min of the insulin clamp (r = -0.43, P < 0.01). In summary, in skeletal muscle of lean

  2. Experimental sink removal induces stress responses, including shifts in amino acid and phenylpropanoid metabolism, in soybean leaves

    PubMed Central

    Turner, Glenn W.; Cuthbertson, Daniel J.; Voo, Siau Sie; Settles, Matthew L.; Grimes, Howard D.

    2012-01-01

    The repeated removal of flower, fruit, or vegetative buds is a common treatment to simulate sink limitation. These experiments usually lead to the accumulation of specific proteins, which are degraded during later stages of seed development, and have thus been designated as vegetative storage proteins. We used oligonucleotide microarrays to assess global effects of sink removal on gene expression patterns in soybean leaves and found an induction of the transcript levels of hundreds of genes with putative roles in the responses to biotic and abiotic stresses. In addition, these data sets indicated potential changes in amino acid and phenylpropanoid metabolism. As a response to sink removal we detected an induced accumulation of γ-aminobutyric acid, while proteinogenic amino acid levels decreased. We also observed a shift in phenylpropanoid metabolism with an increase in isoflavone levels, concomitant with a decrease in flavones and flavonols. Taken together, we provide evidence that sink removal leads to an up-regulation of stress responses in distant leaves, which needs to be considered as an unintended consequence of this experimental treatment. PMID:22109846

  3. Comparison of olfactory receptor (EOG) and bulbar (EEG) responses to amino acids in the catfish, Ictalurus punctatus.

    PubMed

    Byrd, R P; Caprio, J

    1982-10-01

    The olfactory bulb electroencephalogram (EEG) has been used as a method to imply receptor events12,13. However, experiments to correlate olfactory receptor and bulbar EEG activity in the same species of fish has not been performed. Reported here is the comparison between the simultaneously recorded receptor electroolfactogram (EOG) and the bulbar EEG in the channel catfish, Ictalurus punctatus. With amino acid stimulation of the olfactory mucosa, both the EOG and EEG exhibited an initial phasic response followed by a tonic level maintained throughout the stimulus duration. The relative magnitude of the tonic EEG activity (tonic level/phasic response), however, was significantly less than that for the EOG. Both EOG and integrated EEG responses increased exponentially with logarithmic increase in stimulus concentration from threshold to 10(-3) M. Estimated electrophysiological thresholds for 5 amino acids tested determined by both recording methods did not differ significantly and averaged 10(-9.3) +/- 0.2 M for the EOG and 10(-9.1) +/- 0.2 M for the EEG. There was also a significant correlation between the order of relative effectiveness for 11 amino acids determined by EOG and EEG recordings. These results indicate that in the catfish the olfactory bulb EEG is an indicator of olfactory receptor activity. PMID:7139300

  4. Relevance of the two-component sensor protein CiaH to acid and oxidative stress responses in Streptococcus pyogenes

    PubMed Central

    2014-01-01

    Background The production of virulence proteins depends on environmental factors, and two-component regulatory systems are involved in sensing these factors. We previously established knockout strains in all suspected two-component regulatory sensor proteins of the emm1 clinical strain of S. pyogenes and examined their relevance to acid stimuli in a natural atmosphere. In the present study, their relevance to acid stimuli was re-examined in an atmosphere containing 5% CO2. Results The spy1236 (which is identical to ciaHpy) sensor knockout strain showed significant growth reduction compared with the parental strain in broth at pH 6.0, suggesting that the Spy1236 (CiaHpy) two-component sensor protein is involved in acid response of S. pyogenes. CiaH is also conserved in Streptococcus pneumoniae, and it has been reported that deletion of the gene for its cognate response regulator (ciaRpn) made the pneumococcal strains more sensitive to oxidative stress. In this report, we show that the spy1236 knockout mutant of S. pyogenes is more sensitive to oxidative stress than the parental strain. Conclusions These results suggest that the two-component sensor protein CiaH is involved in stress responses in S. pyogenes. PMID:24673808

  5. Sulfur-containing amino acids block stretch-dependent K+ channels and nitrergic responses in the murine colon.

    PubMed

    Park, Kyu Joo; Baker, Salah A; Cho, Sang Yun; Sanders, Kenton M; Koh, Sang Don

    2005-04-01

    1. Efforts to determine the role of stretch-dependent K(+) (SDK) channels in enteric inhibitory neural responses in gastrointestinal muscles are difficult due to a lack of blocking drugs for SDK channels. 2. SDK channels are blocked by sulfur-containing amino acids. These compounds reduced the open probability of SDK channels in on and off-cell patches of murine colonic myocytes. L-Methionine was the most selective and had little or no effect on other known K(+) conductances in colonic myocytes. 3. Application of L-cysteine, L-methionine or DL-homocysteine depolarized intact muscles and enhanced spontaneous contractions. D-Stereoisomers of these amino acids were less effective than L-stereoisomers. 4. Pretreatment of muscles with tetrodotoxin, N(W)-nitro-L-arginine or 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one reduced the depolarization responses to these compounds, suggesting that spontaneous neural activity and release of NO tonically activates SDK channels. 5. Nitrergic responses to nerve stimulation were reduced by sulfur-containing amino acids. 6. These data suggest that nitrergic inhibitory junction potentials are mediated, in part, by activation of SDK channels in murine colonic muscles. PMID:15700022

  6. Effect of acute copper sulfate exposure on olfactory responses to amino acids and pheromones in goldfish (Carassius auratus).

    PubMed

    Kolmakov, Nikolay N; Hubbard, Peter C; Lopes, Orlando; Canario, Adelino V M

    2009-11-01

    Exposure of olfactory epithelium to environmentally relevant concentrations of copper disrupts olfaction in fish. To examine the dynamics of recovery at both functional and morphological levels after acute copper exposure, unilateral exposure of goldfish olfactory epithelia to 100 microM CuSO(4) (10 min) was followed by electro-olfactogram (EOG) recording and scanning electron microscopy. Sensitivity to amino acids (l-arginine and l-serine), generally considered food-related odorants, recovered most rapidly (three days), followed by that to catecholamines (3-O-methoxytyramine), bile acids (taurolithocholic acid) and the steroid pheromone, 17,20beta-dihydroxy-4-pregnen-3-one 20-sulfate, which took 28 days to reach full recovery. Sensitivity to the postovulatory pheromone prostaglandin F(2alpha) had not fully recovered even at 28 days. These changes in sensitivity were correlated with changes in the recovery of ciliated and microvillous receptor cell types. Microvillous cells appeared largely unaffected by CuSO(4) treatment. Cilia in ciliated receptor neurones, however, appeared damaged one day post-treatment and were virtually absent after three days but had begun to recover after 14 days. Together, these results support the hypothesis that microvillous receptor neurones detect amino acids whereas ciliated receptor neurones were not functional and are responsible for detection of social stimuli (bile acids and pheromones). Furthermore, differences in sensitivity to copper may be due to different transduction pathways in the different cell types. PMID:19924975

  7. Detection of acid and hop shock induced responses in beer spoiling Lactobacillus brevis by MALDI-TOF MS.

    PubMed

    Schurr, Benjamin C; Behr, Jürgen; Vogel, Rudi F

    2015-04-01

    Due to the harsh environment, microorganisms encounter in beer, spoilage bacteria must be able to customise their metabolism and physiology in an order to master various kinds of perturbations. Proteomic approaches have been used to examine differences between various beer spoilage bacteria and between different stress conditions, such as acid and hop (Humulus lupulus) stress. However, these investigations cannot detect changes in low molecular weight (lmw) proteins (<150 amino acids). Therefore, for the first time, we herein present data from a proteomic study of lmw proteins for two Lactobacillus (L.) brevis strains exposed to acid stress or, respectively, two different qualities of hop induced stress. We used MALDI-TOF MS as analytical tool for the detection of lmw stress response proteins due to its high sensitivity and low throughput times. Comparing a hop-sensitive and a hop-tolerant strain, detection of the fatty acid biosynthesis-associated acyl carrier protein varied between different stress conditions and incubation times. The findings coincide with previous studies of our group regarding the fatty acid cell membrane composition of beer spoiling L. brevis. It is demonstrated that MALDI-TOF MS is a fast tool to detect and characterise stress situations in beer spoiling bacteria along the lmw sub-proteome. PMID:25475321

  8. Increase of Oleic Acid Content in Phosphatidylcholine through Lipase-catalyzed Interesterification: Optimization by Response Surface Methodology.

    PubMed

    Yang, Guolong; Yang, Lihui

    2015-01-01

    In order to obtain phosphatidylcholine (PC) with higher amount of oleic acid, the interesterification between soybean PC and Camellia oleifera oil (COO) rich in oleic acid catalyzed by lipase was studied in hexane. For this aim three commercially available immobilized lipases (Novozym 435, Lipozyme TLIM and Lipozyme RMIM) were assayed and Novozym 435 was finally selected for further optimization. The effects of the factors, such as PC concentration, substrate ratio, water amount, lipase dosage and temperature, on the oleic acid content in PC and PC recovery during the interesterification were investigated. The conditions of the interesterification were optimized using response surface methodology. The optimum conditions were as follows: lipase dosage 13 % (based on the mass of PC and COO), reaction temperature 55°C, water amount 5% (based on the mass of PC), reaction time 8 h, PC concentration 0.3g/mL (PC/hexane), PC-to-COO ratio 1:3 (acyl groups in PC/acyl groups in COO, mol/mol). Under these conditions, oleic acid content and PC recovery were 40.8 ± 0.5% and 69.0 ± 2.8%, respectively. Analysis of variance (ANOVA) showed that the regression models were adequate for predicting the interesterifiction. The orders of reaction variables affecting on oleic acid content and PC recovery were water amount > reaction time > lipase dosage > reaction temperature, and water amount > reaction temperature > lipase dosage > reaction time, respectively. PMID:25891113

  9. Arabidopsis Sphingolipid Fatty Acid 2-Hydroxylases (AtFAH1 and AtFAH2) Are Functionally Differentiated in Fatty Acid 2-Hydroxylation and Stress Responses1[OA

    PubMed Central

    Nagano, Minoru; Takahara, Kentaro; Fujimoto, Masaru; Tsutsumi, Nobuhiro; Uchimiya, Hirofumi; Kawai-Yamada, Maki

    2012-01-01

    2-Hydroxy fatty acids (2-HFAs) are predominantly present in sphingolipids and have important physicochemical and physiological functions in eukaryotic cells. Recent studies from our group demonstrated that sphingolipid fatty acid 2-hydroxylase (FAH) is required for the function of Arabidopsis (Arabidopsis thaliana) Bax inhibitor-1 (AtBI-1), which is an endoplasmic reticulum membrane-localized cell death suppressor. However, little is known about the function of two Arabidopsis FAH homologs (AtFAH1 and AtFAH2), and it remains unclear whether 2-HFAs participate in cell death regulation. In this study, we found that both AtFAH1 and AtFAH2 had FAH activity, and the interaction with Arabidopsis cytochrome b5 was needed for the sufficient activity. 2-HFA analysis of AtFAH1 knockdown lines and atfah2 mutant showed that AtFAH1 mainly 2-hydroxylated very-long-chain fatty acid (VLCFA), whereas AtFAH2 selectively 2-hydroxylated palmitic acid in Arabidopsis. In addition, 2-HFAs were related to resistance to oxidative stress, and AtFAH1 or 2-hydroxy VLCFA showed particularly strong responses to oxidative stress. Furthermore, AtFAH1 interacted with AtBI-1 via cytochrome b5 more preferentially than AtFAH2. Our results suggest that AtFAH1 and AtFAH2 are functionally different FAHs, and that AtFAH1 or 2-hydroxy VLCFA is a key factor in AtBI-1-mediated cell death suppression. PMID:22635113

  10. The alpha-helical domain of liver fatty acid binding protein is responsible for the diffusion-mediated transfer of fatty acids to phospholipid membranes.

    PubMed

    Córsico, Betina; Liou, Heng Ling; Storch, Judith

    2004-03-30

    Intestinal fatty acid binding protein (IFABP) and liver FABP (LFABP), homologous proteins expressed at high levels in intestinal absorptive cells, employ markedly different mechanisms for the transfer of fatty acids (FAs) to acceptor membranes. Transfer from IFABP occurs during protein-membrane collisional interactions, while for LFABP, transfer occurs by diffusion through the aqueous phase. Earlier, we had shown that the helical domain of IFABP is critical in determining its collisional FA transfer mechanism. In the study presented here, we have engineered a pair of chimeric proteins, one with the "body" (ligand binding domain) of IFABP and the alpha-helical region of LFABP (alphaLbetaIFABP) and the other with the ligand binding pocket of LFABP and the helical domain of IFABP (alphaIbetaLFABP). The objective of this work was to determine whether the change in the alpha-helical domain of each FABP would alter the rate and mechanism of transfer of FA from the chimeric proteins in comparison with those of the wild-type proteins. The fatty acid transfer properties of the FABP chimeras were examined using a fluorescence resonance transfer assay. The results showed a significant modification of the absolute rate of FA transfer from the chimeric proteins compared to that of the wild type, indicating that the slower rate of FA transfer observed for wild-type LFABP relative to that of wild-type IFABP is, in part, determined by the helical domain of the proteins. In addition to these quantitative changes, it was of great interest to observe that the apparent mechanism of FA transfer also changed when the alpha-helical domain was exchanged, with transfer from alphaLbetaIFABP occurring by aqueous diffusion and transfer from alphaIbetaLFABP occurring via protein-membrane collisional interactions. These results demonstrate that the alpha-helical region of LFABP is responsible for its diffusional mechanism of fatty acid transfer to membranes. PMID:15035630

  11. Farnesol biosynthesis in Candida albicans: cellular response to sterol inhibition by zaragozic acid B.

    PubMed

    Hornby, Jacob M; Kebaara, Bessie W; Nickerson, Kenneth W

    2003-07-01

    The dimorphic fungus Candida albicans produces farnesol as a quorum-sensing molecule that regulates cellular morphology. The biosynthetic origin of farnesol has been resolved by treating these cells with zaragozic acid B, a potent inhibitor of squalene synthase in the sterol biosynthetic pathway. Treatment with zaragozic acid B leads to an eightfold increase in the amount of farnesol produced by C. albicans. Furthermore, C. albicans cell extracts contain enzymatic activity to convert [(3)H]farnesyl pyrophosphate to [(3)H]farnesol. Many common antifungal antibiotics (e.g., zaragozic acids, azoles, and allylamines) target steps in sterol biosynthesis. We suggest that the fungicidal activity of zaragozic acid derives in large part from the accumulation of farnesol that accompanies the inhibition of sterol biosynthesis. PMID:12821501

  12. Surviving the Acid Test: Responses of Gram-Positive Bacteria to Low pH

    PubMed Central

    Cotter, Paul D.; Hill, Colin

    2003-01-01

    Gram-positive bacteria possess a myriad of acid resistance systems that can help them to overcome the challenge posed by different acidic environments. In this review the most common mechanisms are described: i.e., the use of proton pumps, the protection or repair of macromolecules, cell membrane changes, production of alkali, induction of pathways by transcriptional regulators, alteration of metabolism, and the role of cell density and cell signaling. We also discuss the reponses of Listeria monocytogenes, Rhodococcus, Mycobacterium, Clostridium perfringens, Staphylococcus aureus, Bacillus cereus, oral streptococci, and lactic acid bacteria to acidic environments and outline ways in which this knowledge has been or may be used to either aid or prevent bacterial survival in low-pH environments. PMID:12966143

  13. DOSE-RESPONSE OF PERFLUOROOCTANOIC ACID-INDUCED IMMUNOMODULATION IN ADULT C57BL/6 MICE

    EPA Science Inventory

    Perfluorooctanoic acid (PFOA), used in fluoropolymer production, is environmentally persistent, present in the human population worldwide, and is associated with myriad health effects under laboratory conditions. A preliminary risk assessment by the US EPA identified immunosuppre...

  14. Response of citrus and other selected plant species to simulated HCL - acid rain

    NASA Technical Reports Server (NTRS)

    Knott, W. M.; Heagle, A. S.

    1980-01-01

    Mature valencia orange trees were sprayed with hydrochloric acid solutions (pH 7.8, 2.0, 1.0, and 0.5) in the field at the full bloom stage and at one month after fruit set. Potted valencia orange and dwarf citrus trees, four species of plants native to Merritt Island, and four agronomic species were exposed to various pH levels of simulated acid rain under controlled conditions. The acid rain was generated from dilutions of hydrochloric acid solutions or by passing water through an exhaust generated by burning solid rocket fuel. The plants were injured severely at pH levels below 1.0, but showed only slight injury at pH levels of 2.0 and above. Threshold injury levels were between 2.0 and 3.0 pH. The sensitivity of the different plant species to acid solutions was similar. Foliar injury symptoms were representative of acid rain including necrosis of young tissue, isolated necrotic spots or patches, and leaf abscission. Mature valencia orange trees sprayed with concentrations of 1.0 pH and 0.5 pH in the field had reduced fruit yields for two harvests after the treatment. All experimental trees were back to full productivity by the third harvest after treatment.

  15. Mapping amino acids of the measles virus hemagglutinin responsible for receptor (CD46) downregulation.