Balancing Cell Migration with Matrix Degradation Enhances Gene Delivery to Cells Cultured Three-Dimensionally Within Hydrogels

PubMed Central

Shepard, Jaclyn A.; Huang, Alyssa; Shikanova, Ariella; Shea, Lonnie D.

2010-01-01

In regenerative medicine, hydrogels are employed to fill defects and support the infiltration of cells that can ultimately regenerate tissue. Gene delivery within hydrogels targeting infiltrating cells has the potential to promote tissue formation, but the delivery efficiency of nonviral vectors within hydrogels is low hindering their applicability in tissue regeneration. To improve their functionality, we have conducted a mechanistic study to investigate the contribution of cell migration and matrix degradation on gene delivery. In this report, lipoplexes were entrapped within hydrogels based on poly(ethylene glycol) (PEG) crosslinked with peptides containing matrix metalloproteinase degradable sequences. The mesh size of these hydrogels is substantially less than the size of the entrapped lipoplexes, which can function to retain vectors. Cell migration and transfection were simultaneously measured within hydrogels with varying density of cell adhesion sites (Arg-Gly-Asp peptides) and solids content. Increasing RGD density increased expression levels up to 100-fold, while greater solids content sustained expression levels for 16 days. Increasing RGD density and decreasing solids content increased cell migration, which indicates expression levels increase with increased cell migration. Initially exposing cells to vector resulted in transient expression that declined after 2 days, verifying the requirement of migration to sustain expression. Transfected cells were predominantly located within the population of migrating cells for hydrogels that supported cell migration. Although the small mesh size retained at least 70% of the lipoplexes in the absence of cells after 32 days, the presence of cells decreased retention to 10% after 16 days. These results indicate that vectors retained within hydrogels contact migrating cells, and that persistent cell migration can maintain elevated expression levels. Thus matrix degradation and cell migration are fundamental design parameters for maximizing gene delivery from hydrogels. PMID:20450944

Difference in light-induced increase in ploidy level and cell size between adaxial and abaxial epidermal pavement cells of Phaseolus vulgaris primary leaves.

PubMed

Kinoshita, Isao; Sanbe, Akiko; Yokomura, E-iti

2008-01-01

Changes in nuclear DNA content and cell size of adaxial and abaxial epidermal pavement cells were investigated using bright light-induced leaf expansion of Phaseolus vulgaris plants. In primary leaves of bean plants grown under high (sunlight) or moderate (ML; photon flux density, 163 micromol m(-2) s(-1)) light, most adaxial epidermal pavement cells had a nucleus with the 4C amount of DNA, whereas most abaxial pavement cells had a 2C nucleus. In contrast, plants grown under low intensity white light (LL; 15 micromol m(-2) s(-1)) for 13 d, when cell proliferation of epidermal pavement cells had already finished, had a 2C nuclear DNA content in most adaxial pavement cells. When these LL-grown plants were transferred to ML, the increase in irradiance raised the frequency of 4C nuclei in adaxial but not in abaxial pavement cells within 4 d. On the other hand, the size of abaxial pavement cells increased by 53% within 4 d of transfer to ML and remained unchanged thereafter, whereas adaxial pavement cells continuously enlarged for 12 d. This suggests that the increase in adaxial cell size after 4 d is supported by the nuclear DNA doubling. The different responses between adaxial and abaxial epidermal cells were not induced by the different light intensity at both surfaces. It was shown that adaxial epidermal cells have a different property than abaxial ones.

Parallel altitudinal clines reveal trends in adaptive evolution of genome size in Zea mays

PubMed Central

Berg, Jeremy J.; Birchler, James A.; Grote, Mark N.; Lorant, Anne; Quezada, Juvenal

2018-01-01

While the vast majority of genome size variation in plants is due to differences in repetitive sequence, we know little about how selection acts on repeat content in natural populations. Here we investigate parallel changes in intraspecific genome size and repeat content of domesticated maize (Zea mays) landraces and their wild relative teosinte across altitudinal gradients in Mesoamerica and South America. We combine genotyping, low coverage whole-genome sequence data, and flow cytometry to test for evidence of selection on genome size and individual repeat abundance. We find that population structure alone cannot explain the observed variation, implying that clinal patterns of genome size are maintained by natural selection. Our modeling additionally provides evidence of selection on individual heterochromatic knob repeats, likely due to their large individual contribution to genome size. To better understand the phenotypes driving selection on genome size, we conducted a growth chamber experiment using a population of highland teosinte exhibiting extensive variation in genome size. We find weak support for a positive correlation between genome size and cell size, but stronger support for a negative correlation between genome size and the rate of cell production. Reanalyzing published data of cell counts in maize shoot apical meristems, we then identify a negative correlation between cell production rate and flowering time. Together, our data suggest a model in which variation in genome size is driven by natural selection on flowering time across altitudinal clines, connecting intraspecific variation in repetitive sequence to important differences in adaptive phenotypes. PMID:29746459

Genome size evolution in Ontario ferns (Polypodiidae): evolutionary correlations with cell size, spore size, and habitat type and an absence of genome downsizing.

PubMed

Henry, Thomas A; Bainard, Jillian D; Newmaster, Steven G

2014-10-01

Genome size is known to correlate with a number of traits in angiosperms, but less is known about the phenotypic correlates of genome size in ferns. We explored genome size variation in relation to a suite of morphological and ecological traits in ferns. Thirty-six fern taxa were collected from wild populations in Ontario, Canada. 2C DNA content was measured using flow cytometry. We tested for genome downsizing following polyploidy using a phylogenetic comparative analysis to explore the correlation between 1Cx DNA content and ploidy. There was no compelling evidence for the occurrence of widespread genome downsizing during the evolution of Ontario ferns. The relationship between genome size and 11 morphological and ecological traits was explored using a phylogenetic principal component regression analysis. Genome size was found to be significantly associated with cell size, spore size, spore type, and habitat type. These results are timely as past and recent studies have found conflicting support for the association between ploidy/genome size and spore size in fern polyploid complexes; this study represents the first comparative analysis of the trend across a broad taxonomic group of ferns.

Analysis of population structures of the microalga Acutodesmus obliquus during lipid production using multi-dimensional single-cell analysis.

PubMed

Sandmann, Michael; Schafberg, Michaela; Lippold, Martin; Rohn, Sascha

2018-04-19

Microalgae bear a great potential to produce lipids for biodiesel, feed, or even food applications. To understand the still not well-known single-cell dynamics during lipid production in microalgae, a novel single-cell analytical technology was applied to study a well-established model experiment. Multidimensional single-cell dynamics were investigated with a non-supervised image analysis technique that utilizes data from epi-fluorescence microscopy. Reliability of this technique was successfully proven via reference analysis. The technique developed was used to determine cell size, chlorophyll amount, neutral lipid amount, and deriving properties on a single-cellular level in cultures of the biotechnologically promising alga Acutodesmus obliquus. The results illustrated a high correlation between cell size and chlorophyll amount, but a very low and dynamic correlation between cell size, lipid amount, and lipid density. During growth conditions under nitrogen starvation, cells with low chlorophyll content tend to start the lipid production first and the cell suspension differentiated in two subpopulations with significantly different lipid contents. Such quantitative characterization of single-cell dynamics of lipid synthesizing algae was done for the first time and the potential of such simple technology is highly relevant to other biotechnological applications and to deeper investigate the process of microalgal lipid accumulation.

Particulate matter from indoor environments of classroom induced higher cytotoxicity and leakiness in human microvascular endothelial cells in comparison with those collected from corridor.

PubMed

Chua, M L; Setyawati, M I; Li, H; Fang, C H Y; Gurusamy, S; Teoh, F T L; Leong, D T; George, S

2017-05-01

We investigated the physicochemical properties (size, shape, elemental composition, and endotoxin) of size resolved particulate matter (PM) collected from the indoor and corridor environments of classrooms. A comparative hazard profiling of these PM was conducted using human microvascular endothelial cells (HMVEC). Oxidative stress-dependent cytotoxicity responses were assessed using quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and high content screening (HCS), and disruption of monolayer cell integrity was assessed using fluorescence microscopy and transwell assay. Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX) analysis showed differences in the morphology and elemental composition of PM of different sizes and origins. While the total mass of PM collected from indoor environment was lower in comparison with those collected from the corridor, the endotoxin content was substantially higher in indoor PM (e.g., ninefold higher endotoxin level in indoor PM 8.1-20 ). The ability to induce oxidative stress-mediated cytotoxicity and leakiness in cell monolayer were higher for indoor PM compared to those collected from the corridor. In conclusion, this comparative analysis suggested that indoor PM is relatively more hazardous to the endothelial system possibly because of higher endotoxin content. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The toxicity, in vitro, of silicon carbide whiskers.

PubMed

Vaughan, G L; Jordan, J; Karr, S

1991-10-01

To mouse cells in culture, SiC whiskers (SiCW) and asbestos are similarly cytotoxic, disrupting cell membranes and killing cells. Both shorten cell generation time, increase the rate of DNA synthesis, increase total cell DNA content, and cause a loss in growth control often associated with malignant cellular transformation. Within the narrow size range of materials examined, the amount of damage appeared to be more a function of the number of whiskers present than of their size. Silicon carbide whiskers, if mishandled, may pose a serious health hazard to humans.

Genome sizes of cranes (Aves: Gruiformes).

PubMed

Rasch, Ellen M

2006-12-01

The DNA content of blood cell nuclei of 15 species of cranes was determined by Feulgen-DNA cytophotometry. Genome sizes agree with values reported elsewhere for several crane species analyzed by flow cytometry. Males have more DNA per cell than females in several species. A karyotype where 2n = 80 is reported for a male greater sandhill crane. Copyright 2006 Wiley-Liss, Inc.

High-content image analysis (HCIA) assay has the highest correlation with direct counting cell suspension compared to the ATP, WST-8 and Alamar blue assays for measurement of cytotoxicity.

PubMed

Tahara, Haruna; Matsuda, Shun; Yamamoto, Yusuke; Yoshizawa, Hiroe; Fujita, Masaharu; Katsuoka, Yasuhiro; Kasahara, Toshihiko

2017-11-01

Various cytotoxicity assays measuring indicators such as enzyme activity, dye uptake, or cellular ATP content are often performed using 96-well microplates. However, recent reports show that cytotoxicity assays such as the ATP assay and MTS assay underestimate cytotoxicity when compounds such as anti-cancer drugs or mutagens induce cell hypertrophy whilst increasing intracellular ATP content. Therefore, we attempted to evaluate the reliability of a high-content image analysis (HCIA) assay to count cell number in a 96-well microplate automatically without using a cell-number indicator. We compared cytotoxicity results of 25 compounds obtained from ATP, WST-8, Alamar blue, and HCIA assays with those directly measured using an automatic cell counter, and repeating individual experiments thrice. The number of compounds showing low correlation in cell viability measured using cytotoxicity assays compared to automatic cell counting (r 2 <0.8, at least 2 of 3 experiments) were follows: ATP assay; 7; WST-8 assay, 2; Alamar blue assay, 3; HCIA cytotoxicity assay, 0. Compounds for which correlation was poor in 3 assays, except the HCIA assay, induced an increase in nuclear and cell size. However, correlation between cell viability measured by automatic cell counter and the HCIA assay was strong regardless of nuclear and cell size. Additionally, correlation coefficients between IC 50 values obtained from automatic cell counter and from cytotoxicity assays were as follows: ATP assay, 0.80; WST-8 assay, 0.84; Alamar blue assay, 0.84; and HCIA assay, 0.98. From the above, we showed that the HCIA cytotoxicity assay produces similar data to the automatic cell counter and is highly accurate in measuring cytotoxicity. Copyright © 2017 Elsevier Inc. All rights reserved.

Inflating bacterial cells by increased protein synthesis

PubMed Central

Basan, Markus; Zhu, Manlu; Dai, Xiongfeng; Warren, Mya; Sévin, Daniel; Wang, Yi-Ping; Hwa, Terence

2015-01-01

Understanding how the homeostasis of cellular size and composition is accomplished by different organisms is an outstanding challenge in biology. For exponentially growing Escherichia coli cells, it is long known that the size of cells exhibits a strong positive relation with their growth rates in different nutrient conditions. Here, we characterized cell sizes in a set of orthogonal growth limitations. We report that cell size and mass exhibit positive or negative dependences with growth rate depending on the growth limitation applied. In particular, synthesizing large amounts of “useless” proteins led to an inversion of the canonical, positive relation, with slow growing cells enlarged 7- to 8-fold compared to cells growing at similar rates under nutrient limitation. Strikingly, this increase in cell size was accompanied by a 3- to 4-fold increase in cellular DNA content at slow growth, reaching up to an amount equivalent to ∼8 chromosomes per cell. Despite drastic changes in cell mass and macromolecular composition, cellular dry mass density remained constant. Our findings reveal an important role of protein synthesis in cell division control. PMID:26519362

Molecular Transport Studies Through Unsupported Lipid Membranes

NASA Astrophysics Data System (ADS)

Rock, William; Parekh, Sapun; Bonn, Mischa

2014-03-01

Dendrimers, spherical polymeric nanoparticles made from branched monomers around a central core, show great promise as drug delivery vehicles. Dendrimer size, core contents, and surface functionality can be synthetically tuned, providing unprecedented versatility. Polyamidoamine (PAMAM) dendrimers have been shown to enter cells; however, questions remain about their biophysical interactions with the cell membrane, specifically about the presence and size of transient pores. We monitor dendrimer-lipid bilayer interactions using unsupported black lipid membranes (BLMs) as model cell membranes. Custom bilayer slides contain two vertically stacked aqueous chambers separated by a 25 μm Teflon sheet with a 120 μm aperture where the bilayer is formed. We vary the composition of model membranes (cholesterol content and lipid phase) to create biomimetic systems and study the interaction of PAMAM G6 and G3 dendrimers with these bilayers. Dendrimers, dextran cargo, and bilayers are monitored and quantified using time-lapse fluorescence imaging. Electrical capacitance measurements are simultaneously recorded to determine if the membrane is porous, and the pore size is deduced by monitoring transport of fluorescent dextrans of increasing molecular weight. These experiments shed light on the importance of cholesterol content and lipid phase on the interaction of dendrimer nanoparticles with membranes.

Introduction for Diffusion Chamber Culture Symposium

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

Carsten, A. L.

The diffusion-chamber system has been applied to studies of cell kinetics, progenitor cell quantitation, humoral effects, immunological effects, cytogenetics, organogenesis, and the cellular effects of drugs and physical factors such as radiation, hypoxia, etc. Chamber contents have been analyzed by clot dissolution with measuring of cell content, limiting dilution evaluation, radionuclide utilization (tritiated thymidine labeling), growth of colony number, size and type, CFU-S or CFU-C content, or proliferation by secondary culture in mice or in vitro systems, and chromosome changes. Cell types ranging from embryonal tissues to adult normal and neoplastic tissues have been grown in hosts across species barriers.more » Advantages and disadvantages of this system are discussed.« less

All Tumor Cells Are Not Created Equal | Center for Cancer Research

Cancer.gov

Cell division is commonly thought of as a process whereby one cell gives rise to two identical daughter cells. However, rare cell divisions are asymmetric, generating daughter cells that may differ in size, developmental potential, or even DNA content. The ability of stem cells to undergo asymmetric division allows them to self-renew while simultaneously generate daughter

Constitutive expression of cell wall invertase genes increases grain yield and starch content in maize.

PubMed

Li, Bei; Liu, Hua; Zhang, Yue; Kang, Tao; Zhang, Li; Tong, Jianhua; Xiao, Langtao; Zhang, Hongxia

2013-12-01

Grain size, number and starch content are important determinants of grain yield and quality. One of the most important biological processes that determine these components is the carbon partitioning during the early grain filling, which requires the function of cell wall invertase. Here, we showed the constitutive expression of cell wall invertase-encoding gene from Arabidopsis, rice (Oryza sativa) or maize (Zea mays), driven by the cauliflower mosaic virus (CaMV) 35S promoter, all increased cell wall invertase activities in different tissues and organs, including leaves and developing seeds, and substantially improved grain yield up to 145.3% in transgenic maize plants as compared to the wild-type plants, an effect that was reproduced in our 2-year field trials at different locations. The dramatically increased grain yield is due to the enlarged ears with both enhanced grain size and grain number. Constitutive expression of the invertase-encoding gene also increased total starch content up to 20% in the transgenic kernels. Our results suggest that cell wall invertase gene can be genetically engineered to improve both grain yield and grain quality in crop plants. © 2013 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

A New Mechanism for the Regulation of Stomatal Aperture Size in Intact Leaves (Accumulation of Mesophyll-Derived Sucrose in the Guard-Cell Wall of Vicia faba).

PubMed Central

Lu, P.; Outlaw Jr, W. H.; Smith, B. G.; Freed, G. A.

1997-01-01

At various times after pulse-labeling broad bean (Vicia faba L.) leaflets with 14CO2, whole-leaf pieces and rinsed epidermal peels were harvested and subsequently processed for histochemical analysis. Cells dissected from whole leaf retained apoplastic contents, whereas those from rinsed peels contained only symplastic contents. Sucrose (Suc)-specific radioactivity peaked (111 GBq mol-1) in palisade cells at 20 min. In contrast, the 14C content and Sucspecific radioactivity were very low in guard cells for 20 min, implying little CO2 incorporation; both then peaked at 40 min. The guard-cell apoplast had a high maximum Suc-specific radioactivity (204 GBq mol-1) and a high Suc influx rate (0.05 pmol stoma-1 min-1). These and other comparisons implied the presence of (a) multiple Suc pools in mesophyll cells, (b) a localized mesophyll-apoplast region that exchanges with phloem and stomata, and (c) mesophyll-derived Suc in guard-cell walls sufficient to diminish stomatal opening by approximately 3 [mu]m. Factors expected to enhance Suc accumulation in guard-cell walls are (a) high transpiration rate, which closes stomata, and (b) high apoplastic Suc concentration, which is elevated when mesophyll Suc efflux exceeds translocation. Therefore, multiple physiological factors are integrated in the attenuation of stomatal aperture size by this previously unrecognized mechanism. PMID:12223693

Model of adipose tissue cellularity dynamics during food restriction.

PubMed

Soula, H A; Géloën, A; Soulage, C O

2015-01-07

Adipose tissue and adipocytes play a central role in the pathogenesis of metabolic diseases related to obesity. Size of fat cells depends on the balance of synthesis and mobilization of lipids and can undergo important variations throughout the life of the organism. These variations usually occur when storing and releasing lipids according to energy demand. In particular when confronted to severe food restriction, adipocyte releases its lipid content via a process called lipolysis. We propose a mathematical model that combines cell diameter distribution and lipolytic response to show that lipid release is a surface (radius squared) limited mechanism. Since this size-dependent rate affects the cell׳s shrinkage speed, we are able to predict the cell size distribution evolution when lipolysis is the only factor at work: such as during an important food restriction. Performing recurrent surgical biopsies on rats, we measured the evolution of adipose cell size distribution for the same individual throughout the duration of the food restriction protocol. We show that our microscopic model of size dependent lipid release can predict macroscopic size distribution evolution. Copyright © 2014 Elsevier Ltd. All rights reserved.

Morphometric Characterization of Rat and Human Alveolar Macrophage Cell Models and their Response to Amiodarone using High Content Image Analysis.

PubMed

Hoffman, Ewelina; Patel, Aateka; Ball, Doug; Klapwijk, Jan; Millar, Val; Kumar, Abhinav; Martin, Abigail; Mahendran, Rhamiya; Dailey, Lea Ann; Forbes, Ben; Hutter, Victoria

2017-12-01

Progress to the clinic may be delayed or prevented when vacuolated or "foamy" alveolar macrophages are observed during non-clinical inhalation toxicology assessment. The first step in developing methods to study this response in vitro is to characterize macrophage cell lines and their response to drug exposures. Human (U937) and rat (NR8383) cell lines and primary rat alveolar macrophages obtained by bronchoalveolar lavage were characterized using high content fluorescence imaging analysis quantification of cell viability, morphometry, and phospholipid and neutral lipid accumulation. Cell health, morphology and lipid content were comparable (p < 0.05) for both cell lines and the primary macrophages in terms of vacuole number, size and lipid content. Responses to amiodarone, a known inducer of phospholipidosis, required analysis of shifts in cell population profiles (the proportion of cells with elevated vacuolation or lipid content) rather than average population data which was insensitive to the changes observed. A high content image analysis assay was developed and used to provide detailed morphological characterization of rat and human alveolar-like macrophages and their response to a phospholipidosis-inducing agent. This provides a basis for development of assays to predict or understand macrophage vacuolation following inhaled drug exposure.

All Tumor Cells Are Not Created Equal | Center for Cancer Research

Cancer.gov

Cell division is commonly thought of as a process whereby one cell gives rise to two identical daughter cells. However, rare cell divisions are asymmetric, generating daughter cells that may differ in size, developmental potential, or even DNA content. The ability of stem cells to undergo asymmetric division allows them to self-renew while simultaneously generate daughter cells committed to differentiating into specialized cell types.

Angular-dependent light scattering from cancer cells in different phases of the cell cycle.

PubMed

Lin, Xiaogang; Wan, Nan; Weng, Lingdong; Zhou, Yong

2017-10-10

Cancer cells in different phases of the cell cycle result in significant differences in light scattering properties. In order to harvest cancer cells in particular phases of the cell cycle, we cultured cancer cells through the process of synchronization. Flow cytometric analysis was applied to check the results of cell synchronization and prepare for light scattering measurements. Angular-dependent light scattering measurements of cancer cells arrested in the G1, S, and G2 phases have been performed. Based on integral calculations for scattering intensities from 5° to 10° and from 110° to 150°, conclusions have been reached. Clearly, the sizes of the cancer cells in different phases of the cell cycle dominated the forward scatter. Accompanying the increase of cell size with the progression of the cell cycle, the forward scattering intensity also increased. Meanwhile, the DNA content of cancer cells in every phase of the cell cycle is responsible for light scattering at large scatter angles. The higher the DNA content of cancer cells was, the greater the positive effect on the high-scattering intensity. As expected, understanding the relationships between the light scattering from cancer cells and cell cycles will aid in the development of cancer diagnoses. Also, it may assist in the guidance of antineoplastic drugs clinically.

Toxicity of copper on the growth of marine microalgae Pavlova sp. and its chlorophyll-a

NASA Astrophysics Data System (ADS)

Purbonegoro, T.; Suratno; Puspitasari, R.; Husna, N. A.

2018-02-01

Marine microalgae is the primary producer at the base of the marine food chain. Their sensitivity to metal contamination provides important information for predicting the environmental impact of pollution. Toxicity testing using marine microalgae Pavlova sp. was carried out to assess the toxicity of copper on the growth and chlorophyll-a content. Results of this study show that adverse effects were observed by the increase of copper concentration. Cell number began to decrease at the lowest concentration (13 μg/L) and reduced drastically at 98 μg/L. Minimum cell number was observed at the highest concentration (890 μg/L). The inhibition concentration (IC50) value of copper for Pavlova sp. was 51.46 μg/L and at concentrations >29 μgL-1 the chlorophyll-a content decreased dramatically compared to the control. A variation in cell size and morphology was also observed at the higher concentration by the increase in the cell size and loss of setae compared to normal cells.

Content vs. Learning: An Old Dichotomy in Science Courses

ERIC Educational Resources Information Center

Bergtrom, Gerald

2011-01-01

The principles of course redesign that were applied to a gateway Cell Biology course at the University of Wisconsin-Milwaukee are applicable to courses large and small, and to institutions of any size. The challenge was to design a content-rich science course that kept pace with present and future content and at the same time use principles of…

Three-dimensional culture of rat calvarial osteoblasts in porous biodegradable polymers

NASA Technical Reports Server (NTRS)

Ishaug-Riley, S. L.; Crane-Kruger, G. M.; Yaszemski, M. J.; Mikos, A. G.

1998-01-01

Neonatal rat calvarial osteoblasts were cultured in 90% porous, 75:25 poly(DL-lactic-co-glycolic acid) (PLGA) foam scaffolds for up to 56 days to examine the effects of the cell seeding density, scaffold pore size, and foam thickness on the proliferation and function of the cells in this three-dimensional environment. Osteoblasts were seeded at either 11.1 x 10(5) or 22.1 x 10(5) cells per cm2 onto PLGA scaffolds having pore sizes in the range of 150-300 or 500-710 microm with a thickness of either 1.9 or 3.2 mm. After 1 day in culture, 75.6 and 68.6% of the seeded cells attached and proliferated on the 1.9 mm thick scaffolds of 150-300 microm pore size for the low and high seeding densities, respectively. The number of osteoblasts continued to increase throughout the study and eventually leveled off near 56 days, as indicated by a quantitative DNA assay. Osteoblast/foam constructs with a low cell seeding density achieved comparable DNA content and alkaline phosphatase (ALPase) activity after 14 days, and mineralization results after 56 days to those with a high cell seeding density. A maximum penetration depth of osseous tissue of 220+/-40 microm was reached after 56 days in the osteoblast/foam constructs of 150-300 microm pore size initially seeded with a high cell density. For constructs of 500-710 microm pore size, the penetration depth was 190+/-40 microm under the same conditions. Scaffold pore size and thickness did not significantly affect the proliferation or function of osteoblasts as demonstrated by DNA content, ALPase activity, and mineralized tissue formation. These data show that comparable bone-like tissues can be engineered in vitro over a 56 day period using different rat calvarial osteoblast seeding densities onto biodegradable polymer scaffolds with pore sizes in the range of 150-710 microm. When compared with the results of a previous study where similar polymer scaffolds were seeded and cultured with marrow stromal cells, this study demonstrates that PLGA foams are suitable substrates for osteoblast growth and differentiated function independent of cell source.

Plant, cell, and molecular mechanisms of abscisic-acid regulation of stomatal apertures. A new mechanism for the regulation of stomatal-aperture size in intact leaves: Accumulation of mesophyll-derived sucrose in the guard-cell wall of Vicia faba L.

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

Lu, P.; Outlaw, W.H. Jr.; Smith, B.G.

At various times after pulse labeling Vicia faba L. leaflets with {sup 14}CO{sub 2}, whole-leaf pieces and rinsed epidermal peels were harvested and subsequently processed for histochemical analysis. Cells dissected from whole leaf retained apoplastic contents whereas those from rinsed peels contained only cytoplastic contents. Sucrose specific radioactivity peaked in palisade cells, 111 GBq{center_dot}mol{sup {minus}1}, at 20 min. In contrast, the {sup 14}C content and sucrose specific radioactivity were very low in guard cells for 20 min, implying little CO{sub 2} incorporation; both then peaked at 40 min. The guard-cell apoplast had a high maximum sucrose specific radioactivity and amore » high sucrose influx rate. These and other comparisons implied the presence of (a) multiple sucrose pools in mesophyll cells, (b) a localized mesophyll-apoplast region that exchanges with phloem and stomata, and (c) mesophyll-derived sucrose in guard-cell walls sufficient to diminish stomatal opening by {approximately} 4 {micro}m. Factors expected to enhance sucrose accumulation in guard-cell walls are (a) high transpiration rate, which closes stomata, and (b) high apoplastic sucrose concentration, which is elevated when mesophyll-sucrose efflux exceeds translocation. Therefore, multiple physiological factors are integrated in the attenuation of stomatal-aperture size by this previously unrecognized mechanism.« less

Modelling cell population growth with applications to cancer therapy in human tumour cell lines.

PubMed

Basse, Britta; Baguley, Bruce C; Marshall, Elaine S; Wake, Graeme C; Wall, David J N

2004-01-01

In this paper we present an overview of the work undertaken to model a population of cells and the effects of cancer therapy. We began with a theoretical one compartment size structured cell population model and investigated its asymptotic steady size distributions (SSDs) (On a cell growth model for plankton, MMB JIMA 21 (2004) 49). However these size distributions are not similar to the DNA (size) distributions obtained experimentally via the flow cytometric analysis of human tumour cell lines (data obtained from the Auckland Cancer Society Research Centre, New Zealand). In our one compartment model, size was a generic term, but in order to obtain realistic steady size distributions we chose size to be DNA content and devised a multi-compartment mathematical model for the cell division cycle where each compartment corresponds to a distinct phase of the cell cycle (J. Math. Biol. 47 (2003) 295). We then incorporated another compartment describing the possible induction of apoptosis (cell death) from mitosis phase (Modelling cell death in human tumour cell lines exposed to anticancer drug paclitaxel, J. Math. Biol. 2004, in press). This enabled us to compare our model to flow cytometric data of a melanoma cell line where the anticancer drug, paclitaxel, had been added. The model gives a dynamic picture of the effects of paclitaxel on the cell cycle. We hope to use the model to describe the effects of other cancer therapies on a number of different cell lines. Copyright 2004 Elsevier Ltd.

Co-precipitation of DEAE-dextran coated SPIONs: how synthesis conditions affect particle properties, stem cell labelling and MR contrast.

PubMed

Barrow, Michael; Taylor, Arthur; García Carrión, Jaime; Mandal, Pranab; Park, B Kevin; Poptani, Harish; Murray, Patricia; Rosseinsky, Matthew J; Adams, Dave J

2016-09-01

Superparamagnetic iron oxide nanoparticles (SPIONs) are widely used as contrast agents for stem cell tracking using magnetic resonance imaging (MRI). The total mass of iron oxide that can be internalised into cells without altering their viability or phenotype is an important criterion for the generation of contrast, with SPIONs designed for efficient labelling of stem cells allowing for an increased sensitivity of detection. Although changes in the ratio of polymer and iron salts in co-precipitation reactions are known to affect the physicochemical properties of SPIONs, particularly core size, the effects of these synthesis conditions on stem cell labelling and magnetic resonance (MR) contrast have not been established. Here, we synthesised a series of cationic SPIONs with very similar hydrodynamic diameters and surface charges, but different polymer content. We have investigated how the amount of polymer in the co-precipitation reaction affects core size and modulates not only the magnetic properties of the SPIONs but also their uptake into stem cells. SPIONs with the largest core size and lowest polymer content presented the highest magnetisation and relaxivity. These particles also had the greatest uptake efficiency without any deleterious effect on either the viability or function of the stem cells. However, for all particles internalised in cells, the T 2 and T 2 * relaxivity was independent of the SPION's core size. Our results indicate that the relative mass of iron taken up by cells is the major determinant of MR contrast generation and suggest that the extent of SPION uptake can be regulated by the amount of polymer used in co-precipitation reactions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Origin of effects of additive solvent on film-morphology in solution-processed nonfullerene solar cells.

PubMed

Chen, Yuxia; Zhang, Xin; Zhan, Chuanlang; Yao, Jiannian

2015-04-01

In this paper, we report an efficient nonfullerene solar cell based on small molecules of p-DTS(FBTTh2)2 and bis-PDI-T. Characterization data indicate that the nature of the acceptor aggregate is a key factor that affects the photocurrent. There is a good relationship between the short-circuit current density (J(SC)) and the phase size of the acceptor-rich domains. The phase size of the acceptor-rich domains is tuned by both the additive types and additive content. As the kind of additive goes from 1-chloronaphthalene (CN) to 1,8-octanedithiol (ODT) and 1,8-diiodooctane (DIO), by this order the solubility of the acceptor in the additive is down, the phase size significantly decreases from over 400 nm down to 30 nm. Also, the acceptor's domain size decreases from 80 to 30 nm as the DIO content ([DIO]) is down from 1% to 0.15%. Following this trend, less DIO remains in the wet film as residue after the host chloroform evaporates, and thus less acceptor can be dissolved in the residue DIO. This decreasing of DIO content acts on the film-morphology similarly as the additive changes down to the one having a lower solubility. Accordingly, our results indicate that it is the dissolved amount of the organic component in the residue additive solvent of the wet film that plays a role in turning the phase size. The efficiency from this small molecule system is significantly raised from 0.02% up to 3.7% by selecting the additive type and fine-tuning the additive content.

Support for the initial attachment, growth and differentiation of MG-63 cells: a comparison between nano-size hydroxyapatite and micro-size hydroxyapatite in composites

PubMed Central

Filová, Elena; Suchý, Tomáš; Sucharda, Zbyněk; Šupová, Monika; Žaloudková, Margit; Balík, Karel; Lisá, Věra; Šlouf, Miroslav; Bačáková, Lucie

2014-01-01

Hydroxyapatite (HA) is considered to be a bioactive material that favorably influences the adhesion, growth, and osteogenic differentiation of osteoblasts. To optimize the cell response on the hydroxyapatite composite, it is desirable to assess the optimum concentration and also the optimum particle size. The aim of our study was to prepare composite materials made of polydimethylsiloxane, polyamide, and nano-sized (N) or micro-sized (M) HA, with an HA content of 0%, 2%, 5%, 10%, 15%, 20%, 25% (v/v) (referred to as N0–N25 or M0–M25), and to evaluate them in vitro in cultures with human osteoblast-like MG-63 cells. For clinical applications, fast osseointegration of the implant into the bone is essential. We observed the greatest initial cell adhesion on composites M10 and N5. Nano-sized HA supported cell growth, especially during the first 3 days of culture. On composites with micro-size HA (2%–15%), MG-63 cells reached the highest densities on day 7. Samples M20 and M25, however, were toxic for MG-63 cells, although these composites supported the production of osteocalcin in these cells. On N2, a higher concentration of osteopontin was found in MG-63 cells. For biomedical applications, the concentration range of 5%–15% (v/v) nano-size or micro-size HA seems to be optimum. PMID:25125978

Assessing mechanical deconstruction of softwood cell wall for cellulosic biofuels production

NASA Astrophysics Data System (ADS)

Jiang, Jinxue

Mechanical deconstruction offers a promising strategy to overcome biomass recalcitrance for facilitating enzymatic hydrolysis of pretreated substrates with zero chemicals input and presence of inhibitors. The goal of this dissertation research is to gain a more fundamental understanding on the impact of mechanical pretreatment on generating digestible micronized-wood and how the physicochemical characteristics influence the subsequent enzymatic hydrolysis of micronized wood. The initial moisture content of feedstock was found to be the key factor affecting the development of physical features and enzymatic hydrolysis of micronized wood. Lower moisture content resulted in much rounder particles with lower crystallinity, while higher moisture content resulted in the milled particles with larger aspect ratio and crystallinity. The enzymatic hydrolysis of micronized wood was improved as collectively increasing surface area (i.e., reducing particle size and aspect ratio) and decreasing crystallinity during mechanical milling pretreatment. Energy efficiency analysis demonstrated that low-moisture content feedstock with multi-step milling process would contribute to cost-effectiveness of mechanical pretreatment for achieving more than 70% of total sugars conversion. In the early stage of mechanical pretreatment, the types of cell fractures were distinguished by the initial moisture contents of wood, leading to interwall fracture at the middle lamella region for low moisture content samples and intrawall fracture at the inner cell wall for high moisture content samples. The changes in cell wall fractures also resulted in difference in the distribution of surface chemical composition and energy required for milling process. In an effort to exploit the underlying mechanism associated with the reduced recalcitrance in micronized wood, we reported the increased enzymatic sugar yield and correspondingly structural and accessible properties of micronized feedstock. Electronic microscopy analysis detailed the structural alternation of cell wall during mechanical process, including cell fracture and delamination, ultrastructure disintegration, and cell wall fragments amorphization, as coincident with the particle size reduction. It was confirmed with Simons' staining that longer milling time resulted in increased substrate accessibility and porosity. The changes in cellulose molecular structure with respect to degree of polymerization (DP) and crystallinity index (CrI) also benefited to decreasing recalcitrance and facilitating enzymatic hydrolysis of micronized wood.

Large-scale generation of cell-derived nanovesicles

NASA Astrophysics Data System (ADS)

Jo, W.; Kim, J.; Yoon, J.; Jeong, D.; Cho, S.; Jeong, H.; Yoon, Y. J.; Kim, S. C.; Gho, Y. S.; Park, J.

2014-09-01

Exosomes are enclosed compartments that are released from cells and that can transport biological contents for the purpose of intercellular communications. Research into exosomes is hindered by their rarity. In this article, we introduce a device that uses centrifugal force and a filter with micro-sized pores to generate a large quantity of cell-derived nanovesicles. The device has a simple polycarbonate structure to hold the filter, and operates in a common centrifuge. Nanovesicles are similar in size and membrane structure to exosomes. Nanovesicles contain intracellular RNAs ranging from microRNA to mRNA, intracellular proteins, and plasma membrane proteins. The quantity of nanovesicles produced using the device is 250 times the quantity of naturally secreted exosomes. Also, the quantity of intracellular contents in nanovesicles is twice that in exosomes. Nanovesicles generated from murine embryonic stem cells can transfer RNAs to target cells. Therefore, this novel device and the nanovesicles that it generates are expected to be used in exosome-related research, and can be applied in various applications such as drug delivery and cell-based therapy.

Graphene-derived Fe/Co-N-C catalyst in direct methanol fuel cells: Effects of the methanol concentration and ionomer content on cell performance

NASA Astrophysics Data System (ADS)

Park, Jong Cheol; Choi, Chang Hyuck

2017-08-01

Non-precious metal catalysts (typically Fe(Co)-N-C catalysts) have been widely investigated for use as cost-effective cathode materials in low temperature fuel cells. Despite the high oxygen reduction activity and methanol-tolerance of graphene-based Fe(Co)-N-C catalysts in an acidic medium, their use in direct methanol fuel cells (DMFCs) has not yet been successfully implemented, and only a few studies have investigated this topic. Herein, we synthesized a nano-sized graphene-derived Fe/Co-N-C catalyst by physical ball-milling and a subsequent chemical modification of the graphene oxide. Twelve membrane-electrode-assemblies are fabricated with various cathode compositions to determine the effects of the methanol concentration, ionomer (i.e. Nafion) content, and catalyst loading on the DMFC performance. The results show that a graphene-based catalyst is capable of tolerating a highly-concentrated methanol feed up to 10.0 M. The optimized electrode composition has an ionomer content and catalyst loading of 66.7 wt% and 5.0 mg cm-2, respectively. The highest maximum power density is ca. 32 mW cm-2 with a relatively low PtRu content (2 mgPtRu cm-2). This study overcomes the drawbacks of conventional graphene-based electrodes using a nano-sized graphene-based catalyst and further shows the feasibility of their potential applications in DMFC systems.

A new mechanism for the regulation of stomatal aperture size in intact leaves: Accumulation of mesophyll-derived sucrose in the guard-cell wall of Vicia faba

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

Lu, Ping; Outlaw, W.H. Jr.; Smith, B.G.

At various times after pulse-labeling broad bean (Vicia faba L.) leaflets with {sup 14}CO{sub 2}, whole-leaf pieces and rinsed epidermal peels were harvested and subsequently processed for histochemical analysis. Cells dissected from whole leaf retained apoplastic contents, whereas those from rinsed peels contained only symplastic contents. Sucrose (Suc)-specific radioactivity peaked (111 GBq mol{sup -1}) in palisade cells at 20 min. In contrast, the {sup 14}C content and Suc-specific radioactivity were very low in guard cells for 20 min, implying little CO, incorporation; both then peaked at 40 min. The guard-cell apoplast had a high maximum Suc-specific radioactivity (204 GBq mol{supmore » -1}) and a high Suc influx rate (0.05 pmol stoma{sup -1} min{sup -1}). These and other comparisons implied the presence of (a) multiple Suc pools in mesophyll cells, M a localized mesophyll-apoplast region that exchanges with phloem and stomata, and mesophyll-derived Suc in guard-cell walls sufficient to diminish stomatal opening by approximately 3 pm. Factors expected to enhance Suc accumulation in guard-cell walls are (a) high transpiration rate, which closes stomata, and N high apoplastic Suc concentration, which is elevated when mesophyll Suc efflux exceeds translocation. Therefore, multiple physiological factors are integrated in the attenuation of stomatal aperture size by this previously unrecognized mechanism. 50 refs., 9 figs.« less

Response of MG63 osteoblast-like cells onto polycarbonate membrane surfaces with different micropore sizes.

PubMed

Lee, Sang Jin; Choi, Jin San; Park, Ki Suk; Khang, Gilson; Lee, Young Moo; Lee, Hai Bang

2004-08-01

Response of different types of cells on materials is important for the applications of tissue engineering and regenerative medicine. It is recognized that the behavior of the cell adhesion, proliferation, and differentiation on materials depends largely on surface characteristics such as wettability, chemistry, charge, rigidity, and roughness. In this study, we examined the behavior of MG63 osteoblast-like cells cultured on a polycarbonate (PC) membrane surfaces with different micropore sizes (0.2-8.0 microm in diameter). Cell adhesion and proliferation to the PC membrane surfaces were determined by cell counting and MTT assay. The effect of surface micropore on the MG63 cells was evaluated by cell morphology, protein content, and alkaline phosphatase (ALP) specific activity. It seems that the cell adhesion and proliferation were progressively inhibited as the PC membranes had micropores with increasing size, probably due to surface discontinuities produced by track-etched pores. Increasing micropore size of the PC membrane results in improved protein synthesis and ALP specific activity in isolated cells. There was a statistically significant difference (P<0.05) between different micropore sizes. The MG63 cells also maintained their phenotype under conditions that support a round cell shape. RT-PCR analysis further confirmed the osteogenic phenotype of the MG63 cells onto the PC membranes with different micropore sizes. In results, as micropore size is getting larger, cell number is reduced and cell differentiation and matrix production is increased. This study demonstrated that the surface topography plays an important role for phenotypic expression of the MG63 osteoblast-like cells.

77 FR 28259 - Mailings of Lithium Batteries

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-14

... containing lithium metal or lithium-ion cells or batteries and applies regardless of quantity, size, watt... ``lithium content'' for secondary lithium-ion batteries when describing maximum quantity limits. In addition...-ion (Rechargeable) Cells and Batteries [Revise 10.20.6 as follows:] Small consumer-type lithium-ion...

DEVELOPMENT, TESTING, AND DEMONSTRATION OF AN OPTIMAL FINE COAL CLEANING CIRCUIT

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

Steven R. Hadley; R. Mike Mishra; Michael Placha

1999-01-27

The objective of this project was to improve the efficiency of the fine coal froth flotation circuit in commercial coal preparation plants. The plant selected for this project, Cyprus Emerald Coal Preparation Plant, cleans 1200-1400 tph of Pittsburgh seam raw coal and uses conventional flotation cells to clean the minus 100-mesh size fraction. The amount of coal in this size fraction is approximately 80 tph with an average ash content of 35%. The project was carried out in two phases. In Phase I, four advanced flotation cells, i.e., a Jameson cell, an Outokumpu HG tank cell, an open column, andmore » a packed column cell, were subjected to bench-scale testing and demonstration. In Phase II, two of these flotation cells, the Jameson cell and the packed column, were subjected to in-plant, proof-of-concept (POC) pilot plant testing both individually and in two-stage combination in order to ascertain whether a two-stage circuit results in lower levelized production costs. The bench-scale results indicated that the Jameson cell and packed column cell would be amenable to the single- and two-stage flotation approach. POC tests using these cells determined that single-stage coal matter recovery (CMR) of 85% was possible with a product ash content of 5.5-7%. Two-stage operation resulted in a coal recovery of 90% with a clean coal ash content of 6-7.5%. This compares favorably with the plant flotation circuit recovery of 80% at a clean coal ash of 11%.« less

Pore size engineering applied to the design of separators for nickel-hydrogen cells and batteries

NASA Technical Reports Server (NTRS)

Abbey, K. M.; Britton, D. L.

1983-01-01

Pore size engineering in starved alkaline multiplate cells involves adopting techniques to widen the volume tolerance of individual cells. Separators with appropriate pore size distributions and wettability characteristics (capillary pressure considerations) to have wider volume tolerances and an ability to resist dimensional changes in the electrodes were designed. The separators studied for potential use in nickel-hydrogen cells consist of polymeric membranes as well as inorganic microporous mats. In addition to standard measurements, the resistance and distribution of electrolyte as a function of total cell electrolyte content were determined. New composite separators consisting of fibers, particles and/or binders deposited on Zircar cloth were developed in order to engineer the proper capillary pressure characteristics in the separator. These asymmetric separators were prepared from a variety of fibers, particles and binders.

Effect of Medium pH on Rhodosporidium toruloides NCYC 921 Carotenoid and Lipid Production Evaluated by Flow Cytometry.

PubMed

Dias, Carla; Silva, Corália; Freitas, Claudia; Reis, Alberto; da Silva, Teresa Lopes

2016-07-01

The effect of the culture medium pH (3.5-6.0) on the carotenoid and lipid (as fatty acids) production by the yeast Rhodosporidium toruloides NCYC 921 was studied. Flow cytometry was used to evaluate the yeast's physiological response to different culture medium pH values. The yeast biomass concentration and lipid content were maxima at pH 4.0 (5.90 g/L and 21.85 % w/w, respectively), while the maximum carotenoid content (63.37 μg/g) was obtained at pH 5.0. At the exponential phase, the yeast cell size and internal complexity were similar, at different medium pH. At the stationary phase, the yeast cell size and internal complexity decreased as the medium pH increased. At the exponential phase, the proportion of cells with polarized membranes was always high (>80 %) but at the stationary phase, the proportion of yeast cells with depolarized membranes was dominant (>65 %) and increased with the medium pH increase. The results here reported may contribute for yeast bioprocesses optimization. For the first time, multiparameter flow cytometry was used to evaluate the impact of medium pH changes on the yeast cell physiological status, specifically on the yeast membrane potential, membrane integrity, cell size and internal complexity.

Increasing seed mass and oil content in transgenic Arabidopsis by the overexpression of wri1-like gene from Brassica napus.

PubMed

Liu, Jing; Hua, Wei; Zhan, Gaomiao; Wei, Fang; Wang, Xinfa; Liu, Guihua; Wang, Hanzhong

2010-01-01

Rapeseed (Brassica napus) is one of the most important edible oilseed crops in the world and is increasingly used globally to produce bio-diesel. Therefore, increasing oil content of oilseed corps is of importance economically in both food and oil industries. The wri1 genes are differentially expressed in B. napus lines with different oil content. To investigate the effects of B. napus WRI1 (BnWRI1) on oil content, two Bnwri1 genes with different lengths, Bnwri1-1 and Bnwri1-2, were identified and sequenced. Homology analysis shows 80% amino acids of Bnwri1s are homologous to Arabidopsis thaliana WRI1 (AtWRI1). Overexpression of Bnwri1 cDNAs driven by cauliflower mosaic virus 35S-promoter in 51 transgenic A. thaliana lines resulted in 10-40% increased seed oil content and enlarged seed size and mass. Detailed analysis on transgenic embryos indicates an increased cell size other than cell number. In addition, Bnwri1 sequence polymorphism is highly related to oil content (p < 0.001). Taking together, Bnwri1 has potential applications in food and oil industries and in rapeseed breeding. Copyright 2009 Elsevier Masson SAS. All rights reserved.

Perturbation of a radially oscillating single-bubble by a micron-sized object.

PubMed

Montes-Quiroz, W; Baillon, F; Louisnard, O; Boyer, B; Espitalier, F

2017-03-01

A single bubble oscillating in a levitation cell is acoustically monitored by a piezo-ceramics microphone glued on the cell external wall. The correlation of the filtered signal recorded over distant cycles on one hand, and its harmonic content on the other hand, are shown to carry rich information on the bubble stability and existence. For example, the harmonic content of the signal is shown to increase drastically once air is fully dissociated in the bubble, and the resulting pure argon bubble enters into the upper branch of the sonoluminescence regime. As a consequence, the bubble disappearance can be unambiguously detected by a net drop in the harmonic content. On the other hand, we perturb a stable sonoluminescing bubble by approaching a micron-sized fiber. The bubble remains unperturbed until the fiber tip is approached within a critical distance, below which the bubble becomes unstable and disappears. This distance can be easily measured by image treatment, and is shown to scale roughly with 3-4 times the bubble maximal radius. The bubble disappearance is well detected by the drop of the microphone harmonic content, but several thousands of periods after the bubble actually disappeared. The delay is attributed to the slow extinction of higher modes of the levitation cell, excited by the bubble oscillation. The acoustic detection method should however allow the early detection and imaging of non-predictable perturbations of the bubble by foreign micron-sized objects, such as crystals or droplets. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of selenium nanoparticles with different sizes in primary cultured intestinal epithelial cells of crucian carp, Carassius auratus gibelio.

PubMed

Wang, Yanbo; Yan, Xuxia; Fu, Linglin

2013-01-01

Nano-selenium (Se), with its high bioavailability and low toxicity, has attracted wide attention for its potential application in the prevention of oxidative damage in animal tissues. However, the effect of nano-Se of different sizes on the intestinal epithelial cells of the crucian carp (Carassius auratus gibelio) is poorly understood. Our study showed that different sizes and doses of nano-Se have varied effects on the cellular protein contents and the enzyme activities of secreted lactate dehydrogenase, intracellular sodium potassium adenosine triphosphatase, glutathione peroxidase, and superoxide dismutase. It was also indicated that nano-Se had a size-dependent effect on the primary intestinal epithelial cells of the crucian carp. Thus, these findings may bring us a step closer to understanding the size effect and the bioavailability of nano-Se on the intestinal tract of the crucian carp.

Effect of selenium nanoparticles with different sizes in primary cultured intestinal epithelial cells of crucian carp, Carassius auratus gibelio

PubMed Central

Wang, Yanbo; Yan, Xuxia; Fu, Linglin

2013-01-01

Nano-selenium (Se), with its high bioavailability and low toxicity, has attracted wide attention for its potential application in the prevention of oxidative damage in animal tissues. However, the effect of nano-Se of different sizes on the intestinal epithelial cells of the crucian carp (Carassius auratus gibelio) is poorly understood. Our study showed that different sizes and doses of nano-Se have varied effects on the cellular protein contents and the enzyme activities of secreted lactate dehydrogenase, intracellular sodium potassium adenosine triphosphatase, glutathione peroxidase, and superoxide dismutase. It was also indicated that nano-Se had a size-dependent effect on the primary intestinal epithelial cells of the crucian carp. Thus, these findings may bring us a step closer to understanding the size effect and the bioavailability of nano-Se on the intestinal tract of the crucian carp. PMID:24204137

On a nonlocal reaction-diffusion-advection system modelling the growth of phytoplankton with cell quota structure

NASA Astrophysics Data System (ADS)

Hsu, Sze-Bi; Mei, Linfeng; Wang, Feng-Bin

2015-11-01

Phytoplankton species in a water column compete for mineral nutrients and light, and the existing models usually neglect differences in the nutrient content and the amount of light absorbed of individuals. In this current paper, we examine a size-structured and nonlocal reaction-diffusion-advection system which describes the dynamics of a single phytoplankton species in a water column where the species depends simply on light for its growth. Our model is under the assumption that the amount of light absorbed by individuals is proportional to cell size, which varies for populations that reproduce by simple division into two equally-sized daughters. We first establish the existence of a critical death rate and our analysis indicates that the phytoplankton survives if and only if its death rate is less than the critical death rate. The critical death rate depends on a general reproductive rate, the characteristics of the water column (e.g., turbulent diffusion rate, sinking, depth), cell growth, cell division, and cell size.

Evolutionary tradeoffs in cellular composition across diverse bacteria

PubMed Central

Kempes, Christopher P; Wang, Lawrence; Amend, Jan P; Doyle, John; Hoehler, Tori

2016-01-01

One of the most important classic and contemporary interests in biology is the connection between cellular composition and physiological function. Decades of research have allowed us to understand the detailed relationship between various cellular components and processes for individual species, and have uncovered common functionality across diverse species. However, there still remains the need for frameworks that can mechanistically predict the tradeoffs between cellular functions and elucidate and interpret average trends across species. Here we provide a comprehensive analysis of how cellular composition changes across the diversity of bacteria as connected with physiological function and metabolism, spanning five orders of magnitude in body size. We present an analysis of the trends with cell volume that covers shifts in genomic, protein, cellular envelope, RNA and ribosomal content. We show that trends in protein content are more complex than a simple proportionality with the overall genome size, and that the number of ribosomes is simply explained by cross-species shifts in biosynthesis requirements. Furthermore, we show that the largest and smallest bacteria are limited by physical space requirements. At the lower end of size, cell volume is dominated by DNA and protein content—the requirement for which predicts a lower limit on cell size that is in good agreement with the smallest observed bacteria. At the upper end of bacterial size, we have identified a point at which the number of ribosomes required for biosynthesis exceeds available cell volume. Between these limits we are able to discuss systematic and dramatic shifts in cellular composition. Much of our analysis is connected with the basic energetics of cells where we show that the scaling of metabolic rate is surprisingly superlinear with all cellular components. PMID:27046336

Pore size engineering applied to the design of separators for nickel-hydrogen cells and batteries

NASA Technical Reports Server (NTRS)

Abbey, K. M.; Britton, D. L.

1983-01-01

Pore size engineering in starved alkaline multiplate cells involves adopting techniques to widen the volume tolerance of individual cells. Separators with appropriate pore size distributions and wettability characteristics (capillary pressure considerations) to have wider volume tolerances and an ability to resist dimensional changes in the electrodes were designed. The separators studied for potential use in nickel-hydrogen cells consist of polymeric membranes as well as inorganic microporous mats. In addition to standard measurements, the resistance and distribution of electrolyte as a function of total cell electrolyte content were determined. New composite separators consisting of fibers, particles and/or binders deposited on Zircar cloth were developed in order to engineer the proper capillary pressure characteristics in the separator. These asymmetric separators were prepared from a variety of fibers, particles and binders. Previously announced in STAR as N83-24571

A High-Content Live-Cell Viability Assay and Its Validation on a Diverse 12K Compound Screen.

PubMed

Chiaravalli, Jeanne; Glickman, J Fraser

2017-08-01

We have developed a new high-content cytotoxicity assay using live cells, called "ImageTOX." We used a high-throughput fluorescence microscope system, image segmentation software, and the combination of Hoechst 33342 and SYTO 17 to simultaneously score the relative size and the intensity of the nuclei, the nuclear membrane permeability, and the cell number in a 384-well microplate format. We then performed a screen of 12,668 diverse compounds and compared the results to a standard cytotoxicity assay. The ImageTOX assay identified similar sets of compounds to the standard cytotoxicity assay, while identifying more compounds having adverse effects on cell structure, earlier in treatment time. The ImageTOX assay uses inexpensive commercially available reagents and facilitates the use of live cells in toxicity screens. Furthermore, we show that we can measure the kinetic profile of compound toxicity in a high-content, high-throughput format, following the same set of cells over an extended period of time.

The color and size of chili peppers (Capsicum annuum) influence Hep-G2 cell growth.

PubMed

Popovich, David G; Sia, Sharon Y; Zhang, Wei; Lim, Mon L

2014-11-01

Four types of chili (Capsicum annuum) extracts, categorized according to color; green and red, and size; small and large were studied in Hep-G2 cells. Red small (RS) chili had an LC50 value of 0.378 ± 0.029 compared to green big (GB) 1.034 ± 0.061 and green small (GS) 1.070 ± 0.21 mg/mL. Red big (RB) was not cytotoxic. Capsaicin content was highest in RS and produced a greater percentage sub-G1 cells (6.47 ± 1.8%) after 24 h compared to GS (2.96 ± 1.3%) and control (1.29 ± 0.8%) cells. G2/M phase was reduced by GS compared to RS and control cells. RS at the LC50 concentration contained 1.6 times the amount of pure capsaicin LC50 to achieve the same effect of capsaicin alone. GS and GB capsaicin content at the LC50 value was lower (0.2 and 0.66, respectively) compared to the amount of capsaicin to achieve a similar reduction in cell growth.

Endoreduplication and fruit growth in tomato: evidence in favour of the karyoplasmic ratio theory.

PubMed

Chevalier, Christian; Bourdon, Matthieu; Pirrello, Julien; Cheniclet, Catherine; Gévaudant, Frédéric; Frangne, Nathalie

2014-06-01

The growth of a plant organ depends upon the developmental processes of cell division and cell expansion. The activity of cell divisions sets the number of cells that will make up the organ; the cell expansion activity then determines its final size. Among the various mechanisms that may influence the determination of cell size, endopolyploidy by means of endoreduplication appears to be of great importance in plants. Endoreduplication is widespread in plants and supports the process of differentiation of cells and organs. Its functional role in plant cells is not fully understood, although it is commonly associated with ploidy-dependent cell expansion. During the development of tomato fruit, cells from the (fleshy) pericarp tissue become highly polyploid, reaching a DNA content barely encountered in other plant species (between 2C and 512C). Recent investigations using tomato fruit development as a model provided new data in favour of the long-standing karyoplasmic ratio theory, stating that cells tend to adjust their cytoplasmic volume to the nuclear DNA content. By establishing a highly structured cellular system where multiple physiological functions are integrated, endoreduplication does act as a morphogenetic factor supporting cell growth during tomato fruit development. © The Author 2013. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Intranuclear DNA density affects chromosome condensation in metazoans

PubMed Central

Hara, Yuki; Iwabuchi, Mari; Ohsumi, Keita; Kimura, Akatsuki

2013-01-01

Chromosome condensation is critical for accurate inheritance of genetic information. The degree of condensation, which is reflected in the size of the condensed chromosomes during mitosis, is not constant. It is differentially regulated in embryonic and somatic cells. In addition to the developmentally programmed regulation of chromosome condensation, there may be adaptive regulation based on spatial parameters such as genomic length or cell size. We propose that chromosome condensation is affected by a spatial parameter called the chromosome amount per nuclear space, or “intranuclear DNA density.” Using Caenorhabditis elegans embryos, we show that condensed chromosome sizes vary during early embryogenesis. Of importance, changing DNA content to haploid or polyploid changes the condensed chromosome size, even at the same developmental stage. Condensed chromosome size correlates with interphase nuclear size. Finally, a reduction in nuclear size in a cell-free system from Xenopus laevis eggs resulted in reduced condensed chromosome sizes. These data support the hypothesis that intranuclear DNA density regulates chromosome condensation. This suggests an adaptive mode of chromosome condensation regulation in metazoans. PMID:23783035

Cell and nuclear enlargement of SW480 cells induced by a plant lignan, arctigenin: evaluation of cellular DNA content using fluorescence microscopy and flow cytometry.

PubMed

Kang, Kyungsu; Lee, Hee Ju; Yoo, Ji-Hye; Jho, Eun Hye; Kim, Chul Young; Kim, Minkyun; Nho, Chu Won

2011-08-01

Arctigenin is a natural plant lignan previously shown to induce G(2)/M arrest in SW480 human colon cancer cells as well as AGS human gastric cancer cells, suggesting its use as a possible cancer chemopreventive agent. Changes in cell and nuclear size often correlate with the functionality of cancer-treating agents. Here, we report that arctigenin induces cell and nuclear enlargement of SW480 cells. Arctigenin clearly induced the formation of giant nuclear shapes in SW480, as demonstrated by fluorescence microscopic observation and quantitative determination of nuclear size. Cell and nuclear size were further assessed by flow cytometric analysis of light scattering and fluorescence pulse width after propidium iodide staining. FSC-H and FL2-W values (parameters referring to cell and nuclear size, respectively) significantly increased after arctigenin treatment; the mean values of FSC-H and FL2-W in arctigenin-treated SW480 cells were 572.6 and 275.1, respectively, whereas those of control cells were 482.0 and 220.7, respectively. Our approach may provide insights into the mechanism behind phytochemical-induced cell and nuclear enlargement as well as functional studies on cancer-treating agents.

Changes of ploidy during the Azotobacter vinelandii growth cycle.

PubMed Central

Maldonado, R; Jiménez, J; Casadesús, J

1994-01-01

The size of the Azotobacter vinelandii chromosome is approximately 4,700 kb, as calculated by pulsed-field electrophoretic separation of fragments digested with the rarely cutting endonucleases SpeI and SwaI. Surveys of DNA content per cell by flow cytometry indicated the existence of ploidy changes during the A. vinelandii growth cycle in rich medium. Early-exponential-phase cells have a ploidy level similar to that of Escherichia coli or Salmonella typhimurium (probably ca. four chromosomes per cell), but a continuous increase of DNA content per cell is observed during growth. Late-exponential-phase cells may contain > 40 chromosomes per cell, while cells in the early stationary stage may contain > 80 chromosomes per cell. In late-stationary-phase cultures, the DNA content per cell is even higher, probably over 100 chromosome equivalents per cell. A dramatic change is observed in old stationary-phase cultures, when the population of highly polyploid bacteria segregates cells with low ploidy. The DNA content of the latter cells resembles that of cysts, suggesting that the process may reflect the onset of cyst differentiation. Cells with low ploidy are also formed when old stationary-phase cultures are diluted into fresh medium. Addition of rifampin to exponential-phase cultures causes a rapid increase in DNA content, indicating that A. vinelandii initiates multiple rounds of chromosome replication per cell division. Growth in minimal medium does not result in the spectacular changes of ploidy observed during rapid growth; this observation suggests that the polyploidy of A. vinelandii may not exist outside the laboratory. Images PMID:8021173

Deterministic Encapsulation of Human Cardiac Stem Cells in Variable Composition Nanoporous Gel Cocoons To Enhance Therapeutic Repair of Injured Myocardium.

PubMed

Kanda, Pushpinder; Alarcon, Emilio I; Yeuchyk, Tanya; Parent, Sandrine; de Kemp, Robert A; Variola, Fabio; Courtman, David; Stewart, Duncan J; Davis, Darryl R

2018-04-20

Although cocooning explant-derived cardiac stem cells (EDCs) in protective nanoporous gels (NPGs) prior to intramyocardial injection boosts long-term cell retention, the number of EDCs that finally engraft is trivial and unlikely to account for salutary effects on myocardial function and scar size. As such, we investigated the effect of varying the NPG content within capsules to alter the physical properties of cocoons without influencing cocoon dimensions. Increasing NPG concentration enhanced cell migration and viability while improving cell-mediated repair of injured myocardium. Given that the latter occurred with NPG content having no detectable effect on the long-term engraftment of transplanted cells, we found that changing the physical properties of cocoons prompted explant-derived cardiac stem cells to produce greater amounts of cytokines, nanovesicles, and microRNAs that boosted the generation of new blood vessels and new cardiomyocytes. Thus, by altering the physical properties of cocoons by varying NPG content, the paracrine signature of encapsulated cells can be enhanced to promote greater endogenous repair of injured myocardium.

Extrusion foaming of protein-based thermoplastic and polyethylene blends

NASA Astrophysics Data System (ADS)

Gavin, Chanelle; Lay, Mark C.; Verbeek, Casparus J. R.

2016-03-01

Currently the extrusion foamability of Novatein® Thermoplastic Protein (NTP) is being investigated at the University of Waikato in collaboration with the Biopolymer Network Ltd (NZ). NTP has been developed from bloodmeal (>86 wt% protein), a co-product of the meat industry, by adding denaturants and plasticisers (tri-ethylene glycol and water) allowing it to be extruded and injection moulded. NTP alone does not readily foam when sodium bicarbonate is used as a chemical blowing agent as its extensional viscosity is too high. The thermoplastic properties of NTP were modified by blending it with different weight fractions of linear low density polyethylene (LLDPE) and polyethylene grafted maleic anhydride (PE-g-MAH) compatibiliser. Extrusion foaming was conducted in two ways, firstly using the existing water content in the material as the blowing agent and secondly by adding sodium bicarbonate. When processed in a twin screw extruder (L/D 25 and 10 mm die) the material readily expanded due to the internal moisture content alone, with a conditioned expansion ratio of up to ± 0.13. Cell structure was non-uniform exhibiting a broad range cell sizes at various stages of formation with some coalescence. The cell size reduced through the addition of sodium bicarbonate, overall more cells were observed and the structure was more uniform, however ruptured cells were also visible on the extrudate skin. Increasing die temperature and introducing water cooling reduced cell size, but the increased die temperature resulted in surface degradation.

Statistical analysis and modeling of pelletized cultivation of Mucor circinelloides for microbial lipid accumulation.

PubMed

Xia, Chunjie; Wei, Wei; Hu, Bo

2014-04-01

Microbial oil accumulation via oleaginous fungi has some potential benefits because filamentous fungi can form pellets during cell growth and these pellets are easier to harvest from the culture broth than individual cells. This research studied the effect of various culture conditions on the pelletized cell growth of Mucor circinelloides and its lipid accumulation. The results showed that cell pelletization was positively correlated to biomass accumulation; however, pellet size was negatively correlated to the oil content of the fungal biomass, possibly due to the mass transfer barriers generated by the pellet structure. How to control the size of the pellet is the key to the success of the pelletized microbial oil accumulation process.

PEMFC catalyst layers: the role of micropores and mesopores on water sorption and fuel cell activity.

PubMed

Soboleva, Tatyana; Malek, Kourosh; Xie, Zhong; Navessin, Titichai; Holdcroft, Steven

2011-06-01

The effects of carbon microstructure and ionomer loading on water vapor sorption and retention in catalyst layers (CLs) of PEM fuel cells are investigated using dynamic vapor sorption. Catalyst layers based on Ketjen Black and Vulcan XC-72 carbon blacks, which possess distinctly different surface areas, pore volumes, and microporosities, are studied. It is found that pores <20 nm diameter facilitate water uptake by capillary condensation in the intermediate range of relative humidities. A broad pore size distribution (PSD) is found to enhance water retention in Ketjen Black-based CLs whereas the narrower mesoporous PSD of Vulcan CLs is shown to have an enhanced water repelling action. Water vapor sorption and retention properties of CLs are correlated to electrochemical properties and fuel cell performance. Water sorption enhances electrochemical properties such as the electrochemically active surface area (ESA), double layer capacitance and proton conductivity, particularly when the ionomer content is very low. The hydrophilic properties of a CL on the anode and the cathode are adjusted by choosing the PSD of carbon and the ionomer content. It is shown that a reduction of ionomer content on either cathode or anode of an MEA does not necessarily have a significant detrimental effect on the MEA performance compared to the standard 30 wt % ionomer MEA. Under operation in air and high relative humidity, a cathode with a narrow pore size distribution and low ionomer content is shown to be beneficial due to its low water retention properties. In dry operating conditions, adequate ionomer content on the cathode is crucial, whereas it can be reduced on the anode without a significant impact on fuel cell performance. © 2011 American Chemical Society

Shifts in growth strategies reflect tradeoffs in cellular economics

PubMed Central

Molenaar, Douwe; van Berlo, Rogier; de Ridder, Dick; Teusink, Bas

2009-01-01

The growth rate-dependent regulation of cell size, ribosomal content, and metabolic efficiency follows a common pattern in unicellular organisms: with increasing growth rates, cell size and ribosomal content increase and a shift to energetically inefficient metabolism takes place. The latter two phenomena are also observed in fast growing tumour cells and cell lines. These patterns suggest a fundamental principle of design. In biology such designs can often be understood as the result of the optimization of fitness. Here we show that in basic models of self-replicating systems these patterns are the consequence of maximizing the growth rate. Whereas most models of cellular growth consider a part of physiology, for instance only metabolism, the approach presented here integrates several subsystems to a complete self-replicating system. Such models can yield fundamentally different optimal strategies. In particular, it is shown how the shift in metabolic efficiency originates from a tradeoff between investments in enzyme synthesis and metabolic yields for alternative catabolic pathways. The models elucidate how the optimization of growth by natural selection shapes growth strategies. PMID:19888218

Comprehensive assessment of three typical antibiotics on cyanobacteria (Microcystis aeruginosa): The impact and recovery capability.

PubMed

Du, Yingxiang; Wang, Jing; Zhu, Fengyi; Mai, Dina; Xiang, Zhongrun; Chen, Jianqiu; Guo, Ruixin

2018-05-21

This innovative study provided a comprehensive evaluation of the effects of three typical antibiotics exposures (cefradine, norfloxacin and amoxicillin) on Microcystis aeruginosa in two periods (exposure and post-exposure) at a new perspective. The results indicated that the irreversible growth inhibition of M. aeruginosa attributed to the norfloxacin in the exposure and the re-exposure stages. In contrast, although the algal cell size recovered to the control level after the exposure of 20 mg/L of cefradine, the significant stimulation on glutathione (GSH) still persisted even if the contaminants were removed. On the other hand, amoxicillin inhibited the activities of superoxide dismutase (SOD), GSH contents and the algal cell size in the exposure period while malonaldehyde (MDA) contents increased significantly in two periods. Copyright © 2018 Elsevier Inc. All rights reserved.

Clinorotation [correction of Clinoratation] effects on the structural-functional response in potato minitubers.

PubMed

Nedukha, O; Kordyum, E; Ovrutska, I; Martyn, G; Shnyukova, E

2001-07-01

It is established that high plant growth and development in microgravity occurred normal. However, the change of plant growth rate is accompanied by the change of carbohydrate metabolism in photosynthesized cells (Kordyum, 1997). The decrease of starch grain size in chloroplasts and the decrease of content cellulose in cell wall were revealed (Sytnik et al., 1984; Nedukha, 1996). The change carbohydrate metabolism in photosynthesized organs could influence on the growth of underground organs and content of storage carbohydrates in these organs. Therefore, the aim of our study was to investigate the long-term clinorotation influence on the formation, structure of potato minitubers and content of starch and sugars in minitubers.

Diel Variations in Optical Properties of Micromonas pusilla, a Prasinophyte

NASA Technical Reports Server (NTRS)

DuRand, Michele D.; Green, Rebecca E.; Sosik, Heidi M.; Olson, Robert J.

2001-01-01

A laboratory experiment was conducted on cultures of Micromonas pusilla, a marine prasinophyte, to investigate how cell growth and division affect the optical properties over the light:dark cycle. Measurements were made of cell size and concentration, attenuation and absorption coefficients, flow cytometric light scattering (in forward and side directions), chlorophyll and carbon content. Refractive index was calculated using the anomalous diffraction approximation Cells were about 1.5 micrometers in diameter and exhibited phased division, with the major division burst occurring during the night. Typical diel variations were observed, with cells increasing in size and light scattering during the day as they photosynthesize and decreasing at night upon division. The cells were in ultradian growth, with more than one division per day, at a light level of 120 Mu-mol photons m/sq/sec. Since these cells are similar in size to small phytoplankton that are typically abundant in field samples, these results can be used in the interpretation of diel variations in light scattering in natural populations of phytoplankton.

Iso-acoustic focusing of cells for size-insensitive acousto-mechanical phenotyping

PubMed Central

Augustsson, Per; Karlsen, Jonas T.; Su, Hao-Wei; Bruus, Henrik; Voldman, Joel

2016-01-01

Mechanical phenotyping of single cells is an emerging tool for cell classification, enabling assessment of effective parameters relating to cells' interior molecular content and structure. Here, we present iso-acoustic focusing, an equilibrium method to analyze the effective acoustic impedance of single cells in continuous flow. While flowing through a microchannel, cells migrate sideways, influenced by an acoustic field, into streams of increasing acoustic impedance, until reaching their cell-type specific point of zero acoustic contrast. We establish an experimental procedure and provide theoretical justifications and models for iso-acoustic focusing. We describe a method for providing a suitable acoustic contrast gradient in a cell-friendly medium, and use acoustic forces to maintain that gradient in the presence of destabilizing forces. Applying this method we demonstrate iso-acoustic focusing of cell lines and leukocytes, showing that acoustic properties provide phenotypic information independent of size. PMID:27180912

Iso-acoustic focusing of cells for size-insensitive acousto-mechanical phenotyping.

PubMed

Augustsson, Per; Karlsen, Jonas T; Su, Hao-Wei; Bruus, Henrik; Voldman, Joel

2016-05-16

Mechanical phenotyping of single cells is an emerging tool for cell classification, enabling assessment of effective parameters relating to cells' interior molecular content and structure. Here, we present iso-acoustic focusing, an equilibrium method to analyze the effective acoustic impedance of single cells in continuous flow. While flowing through a microchannel, cells migrate sideways, influenced by an acoustic field, into streams of increasing acoustic impedance, until reaching their cell-type specific point of zero acoustic contrast. We establish an experimental procedure and provide theoretical justifications and models for iso-acoustic focusing. We describe a method for providing a suitable acoustic contrast gradient in a cell-friendly medium, and use acoustic forces to maintain that gradient in the presence of destabilizing forces. Applying this method we demonstrate iso-acoustic focusing of cell lines and leukocytes, showing that acoustic properties provide phenotypic information independent of size.

Novel soy protein scaffolds for tissue regeneration: Material characterization and interaction with human mesenchymal stem cells.

PubMed

Chien, Karen B; Shah, Ramille N

2012-02-01

Soy protein modified with heat treatment and enzyme crosslinking using transglutaminase in maltodextrin was used to fabricate novel, porous three-dimensional scaffolds through lyophilization. Physical properties of scaffolds were characterized using scanning electron microscopy, mercury intrusion porosimetry, moisture content analysis and mechanical testing. Human mesenchymal stem cells (hMSC) were seeded and cultured in vitro on the scaffolds for up to 2 weeks, and changes in stem cell growth and morphology were examined. The resulting scaffolds had rough surfaces, irregular pores with size distributions between 10 and 125 μm, <5% moisture content and compressive moduli ranging between 50 and 100 Pa. Enzyme treatment significantly lowered the moisture content. Increasing amounts of applied enzyme units lowered the median pore size. Although enzyme treatment did not affect the mechanical properties of the scaffolds, it did increase the degradation time by at least 1 week. These changes in scaffold degradation altered the growth and morphology of seeded hMSC. Cell proliferation was observed in scaffolds containing 3% soy protein isolate treated with 1 U of transglutaminase. These results demonstrate that controlling scaffold degradation rates is crucial for optimizing hMSC growth on soy protein scaffolds and that soy protein scaffolds have the potential to be used in tissue engineering applications. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Cellular metabolic rates from primary dermal fibroblast cells isolated from birds of different body masses.

PubMed

Jimenez, Ana Gabriela; Williams, Joseph B

2014-10-01

The rate of metabolism is the speed at which organisms use energy, an integration of energy transformations within the body; it governs biological processes that influence rates of growth and reproduction. Progress at understanding functional linkages between whole organism metabolic rate and underlying mechanisms that influence its magnitude has been slow despite the central role this issue plays in evolutionary and physiological ecology. Previous studies that have attempted to relate how cellular processes translate into whole-organism physiology have done so over a range of body masses of subjects. However, the data still remains controversial when observing metabolic rates at the cellular level. To bridge the gap between these ideas, we examined cellular metabolic rate of primary dermal fibroblasts isolated from 49 species of birds representing a 32,000-fold range in body masses to test the hypothesis that metabolic rate of cultured cells scales with body size. We used a Seahorse XF-96 Extracellular flux analyzer to measure cellular respiration in fibroblasts. Additionally, we measured fibroblast size and mitochondrial content. We found no significant correlation between cellular metabolic rate, cell size, or mitochondrial content and body mass. Additionally, there was a significant relationship between cellular basal metabolic rate and proton leak in these cells. We conclude that metabolic rate of cells isolated in culture does not scale with body mass, but cellular metabolic rate is correlated to growth rate in birds. Copyright © 2014 Elsevier Inc. All rights reserved.

The structure of tissue on cell culture-extracted thyroglobulin is independent of its iodine content.

PubMed

Delain, E; Aouani, A; Vignal, A; Couture-Tosi, E; Hovsépian, S; Fayet, G

1987-02-01

The major protein synthesized in vitro by the ovine thyroid cell line OVNIS 6H is the prothyroid hormone thyroglobulin. Purified from serum-free cell culture media using sucrose gradient centrifugation, the thyroglobulin dimer was analysed for iodine content and observed by electron microscopy. In their usual medium, the OVNIS 6H cells produce a very poorly iodinated thyroglobulin containing 0.05 I atom per molecule. When cultured with methimazole or propylthiouracil, two inhibitors of iodide organification, less than 0.007 I atom/molecules was found. These molecules purified from cell cultures were compared to those purified from ovine thyroid tissue containing 26 I atoms/mol. Despite large differences in iodine content, the three preparations all consist of 19 S thyroglobulin dimers with the classical ovoidal shape. The variability in size measurements remains in a 2% range for all thyroglobulin types. Consequently, no real significant variation can be found between the highly iodinated thyroglobulin isolated from tissue, and the poorly or non-iodinated thyroglobulins isolated from cells cultured with or without methimazole or propylthiouracil.

Effects of decreasing resolution on spectral and spatial information content in an agricultural area. [Pottawatmie study site, Iowa and Nebraska

NASA Technical Reports Server (NTRS)

1983-01-01

The effects of decreasing spatial resolution from 6 1/4 miles square to 50 miles square are described. The effects of increases in cell size is studied on; the mean and variance of spectral data; spatial trends; and vegetative index numbers. Information content changes on cadastral, vegetal, soil, water and physiographic information are summarized.

Preparation and Structure Study of Water-Blown Polyurethane/RDX Gun Propellant Foams

NASA Astrophysics Data System (ADS)

Yang, Weitao; Yang, Jianxing; Zhao, Yuhua; Zhang, Yucheng

2018-01-01

Water-blown polyurethane/RDX foamed propellants were prepared using polyols and isocyanate as reactive binder system, hexogen (RDX) as energetic component, triethanolamine (TEA)/Ditin butyl dilaurate (T-12) as composite catalysts, and H2O as blowing agent. The influences of catalyst ratio, blowing agent amount, and solid filler content on the inner porous structure were studied. The results show that the balance of gel rate and cream rate that could be adjusted by catalyst ratio is a major influencing factor on porous structure of foamed propellants. When the ratio of TEA/T-12 was adjusted to 1/0.7, the morphology of the foamed propellant exhibited spherical and closed porous structure. Besides, when the water amount was increased from 0.1% to 0.5%, the pore size increased from 0.43 to 0.64 mm. The contents of RDX particles affected the cell nucleation and thus, the cell geometry. When the blowing agent amount was constant, the increased content of RDX filler led to a decreased pore size. The closed bomb test results showed that foamed propellants burned progressively in an in-depth combustion mode.

New strategy for design and fabrication of polymer hydrogel with tunable porosity as artificial corneal skirt.

PubMed

Cao, Danfeng; Zhang, Yingchao; Cui, Zhanchen; Du, Yuanyuan; Shi, Zuosen

2017-01-01

In order to obtain an ideal material using for artificial corneal skirt, a porous polymer hydrogel containing 2-hydroxyethyl methacrylate (HEMA), trimethylolpropane triacrylate (TMPTA) and butyl acrylate was prepared through one-step radical polymerization method and the usage of CaCO 3 whisker as porogen. The physical-chemical properties of the fabricated polymer hydrogel can be adjusted by CaCO 3 whisker content, such as pore size, porosity, water content of materials and surface topography. Then a series of cell biology experiments of human corneal fibroblasts (HCFs) were carried out to evaluate its properties as an artificial corneal skirt, such as the adhesion of cells on the materials with different pore size and porosity, the apoptosis on materials with different characteristics, the distribution of the cells on the material surface. The results revealed that high porosity not only could improve water content of hydrogel, but also strengthen the adhesion of HCFs on hydrogel. In addition, high porosity hydrogel with the whisker shape of pores showed much elongate spindle-like morphology than those low porosity hydrogels. MTT assay certified that the resulted polymer hydrogel material possessed excellent biocompatibility and was suitable for HCFs growing, making it promising for being developed as artificial corneal skirt. Copyright © 2016 Elsevier B.V. All rights reserved.

[Neuronal organization of thalamic nucleus reticularis in adult man].

PubMed

Berezhnaia, L A

2005-01-01

The neuronal content of human thalamic nucleus reticularis was studied in serial sections cut in sagittal and frontal projections and impregnated with silver nitrate using Golgi method. The neuronal content of human thalamic nucleus reticularis was found to be more diverse than previously reported in animals and man. Besides two types of sparsely-branched long-dendritic spineless R1 and R2 neurons, this nucleus contained spiny cells. Medium and small-sized sparsely-branched short-dendritic neurons and densely-branched spiny cells were demonstrated. The principle of organization of human thalamic nucleus reticularis is described.

Effects of cortisone on regenerating rat liver.

PubMed

EINHORN, S L; HIRSCHBERG, E; GELLHORN, A

1954-03-01

The effects of continuous administration of cortisone on the metabolism of regenerating rat liver have been studied. Whereas the restoration of the weight of the liver after partial hepatectomy was not markedly affected by cortisone, the multiplication of cells was reduced to a significant degree after the first 2 days of regeneration. Liver restoration in terms of nucleic acids was similarly inhibited by cortisone. The results are consistent with the interpretation that the inhibition of cell multiplication in this system is dependent on and keeps pace with the inhibition of nucleic acid synthesis by this drug. At almost any time after hepatectomy, the nucleic acid content of the liver cells was the same in treated and in untreated animals. In ancillary studies, it was shown that cortisone caused the cells of regenerating liver to be increased in size and weight through the increased infiltration of lipids. Changes in water, protein, and carbohydrate content of the liver cells did not contribute to this increase in the weight of the cells. Since all animals were treated with cortisone for 5 days before hepatectomy, data were also obtained on the effect of this agent on the resting liver. This course of treatment brought about a significant decrease in the number of cells per unit wet weight and in the water content of the livers. The nucleic acid content of the cells at hepatectomy, on the other hand, was unchanged.

Analysis for nickel (3 and 4) in positive plates from nickel-cadmium cells

NASA Technical Reports Server (NTRS)

Lewis, Harlan L.

1994-01-01

The NASA-Goddard procedure for destructive physical analysis (DPA) of nickel-cadmium cells contains a method for analysis of residual charged nickel as NiOOH in the positive plates at complete cell discharge, also known as nickel precharge. In the method, the Ni(III) is treated with an excess of an Fe(II) reducing agent and then back titrated with permanganate. The Ni(III) content is the difference between Fe(II) equivalents and permanganate equivalents. Problems have arisen in analysis at NAVSURFWARCENDIV, Crane because for many types of cells, particularly AA-size and some 'space-qualified' cells, zero or negative Ni(III) contents are recorded for which the manufacturer claims 3-5 percent precharge. Our approach to this problem was to reexamine the procedure for the source of error, and correct it or develop an alternative method.

Effect of water deficit on the cell wall of the date palm (Phoenix dactylifera 'Deglet nour', Arecales) fruit during development.

PubMed

Gribaa, Ali; Dardelle, Flavien; Lehner, Arnaud; Rihouey, Christophe; Burel, Carole; Ferchichi, Ali; Driouich, Azeddine; Mollet, Jean-Claude

2013-05-01

Date palm (Phoenix dactylifera) is an important crop providing a valuable nutrition source for people in many countries including the Middle East and North Africa. In recent years, the amount of rain in North Africa and especially in the Tunisian palm grove areas has dropped significantly. We investigated the growth and cell wall remodelling of fruits harvested at three key development stages from trees grown with or without water supply. During development, cell wall solubilization and remodelling was characterized by a decrease of the degree of methylesterification of pectin, an important loss of galactose content and a reduction of the branching of xylan by arabinose in irrigated condition. Water deficit had a profound effect on fruit size, pulp content, cell wall composition and remodelling. Loss of galactose content was not as important, arabinose content was significantly higher in the pectin-enriched extracts from non-irrigated condition, and the levels of methylesterification of pectin and O-acetylation of xyloglucan were lower than in irrigated condition. The lower levels of hydrophobic groups (methylester and O-acetyl) and the less intensive degradation of the hydrophilic galactan, arabinan and arabinogalactan in the cell wall may be implicated in maintaining the hydration status of the cells under water deficit. © 2012 Blackwell Publishing Ltd.

Isolation and partial characterization of mutants with elevated lipid content in Chlorella sorokiniana and Scenedesmus obliquus.

PubMed

Vigeolas, Hélène; Duby, Francéline; Kaymak, Esra; Niessen, Guillaume; Motte, Patrick; Franck, Fabrice; Remacle, Claire

2012-11-30

This paper describes the isolation and partial biomass characterization of high triacylglycerol (TAG) mutants of Chlorella sorokiniana and Scenedesmus obliquus, two algal species considered as potential source of biodiesel. Following UV mutagenesis, 2000 Chlorella and 2800 Scenedesmus colonies were screened with a method based on Nile Red fluorescence. Several mutants with high Nile Red fluorescence were selected by this high-throughput method in both species. Growth and biomass parameters of the strongest mutants were analyzed in detail. All of the four Chlorella mutants showed no significant changes in growth rate, cell weight, cell size, protein and chlorophyll contents on a per cell basis. Whereas all contained elevated total lipid and TAG content per unit of dry weight, two of them were also affected for starch metabolism, suggesting a change in biomass/storage carbohydrate composition. Two Scenedesmus mutants showed a 1.5 and 2-fold increased cell weight and larger cells compared to the wild type, which led to a general increase of biomass including total lipid and TAG content on a per cell basis. Such mutants could subsequently be used as commercial oleaginous algae and serve as an alternative to conventional petrol. Copyright © 2012 Elsevier B.V. All rights reserved.

Proteomic and comparative genomic analysis of two Brassica napus lines differing in oil content.

PubMed

Gan, Lu; Zhang, Chun-yu; Wang, Xiao-dong; Wang, Hao; Long, Yan; Yin, Yong-tai; Li, Dian-rong; Tian, Jian-Hua; Li, Zai-yun; Lin, Zhi-wei; Yu, Long-Jiang; Li, Mao-Teng

2013-11-01

Ultrastructural observations, combined with proteomic and comparative genomic analyses, were applied to interpret the differences in protein composition and oil-body characteristics of mature seed of two Brassica napus lines with high and low oil contents of 55.19% and 36.49%, respectively. The results showed that oil bodies were arranged much closer in the high than in the low oil content line, and differences in cell size and thickness of cell walls were also observed. There were 119 and 32 differentially expressed proteins (DEPs) of total and oil-body proteins identified. The 119 DEPs of total protein were mainly involved in the oil-related, dehydration-related, storage and defense/disease, and some of these may be related to oil formation. The DEPs involved with dehydration-related were both detected in total and oil-body proteins for high and low oil lines and may be correlated with the number and size of oil bodies in the different lines. Some genes that corresponded to DEPs were confirmed by quantitative trait loci (QTL) mapping analysis for oil content. The results revealed that some candidate genes deduced from DEPs were located in the confidence intervals of QTL for oil content. Finally, the function of one gene that coded storage protein was verified by using a collection of Arabidopsis lines that can conditionally express the full length cDNA from developing seeds of B. napus.

TPC2 controls pigmentation by regulating melanosome pH and size.

PubMed

Ambrosio, Andrea L; Boyle, Judith A; Aradi, Al E; Christian, Keith A; Di Pietro, Santiago M

2016-05-17

Melanin is responsible for pigmentation of skin and hair and is synthesized in a specialized organelle, the melanosome, in melanocytes. A genome-wide association study revealed that the two pore segment channel 2 (TPCN2) gene is strongly linked to pigmentation variations. TPCN2 encodes the two-pore channel 2 (TPC2) protein, a cation channel. Nevertheless, how TPC2 regulates pigmentation remains unknown. Here, we show that TPC2 is expressed in melanocytes and localizes to the melanosome-limiting membrane and, to a lesser extent, to endolysosomal compartments by confocal fluorescence and immunogold electron microscopy. Immunomagnetic isolation of TPC2-containing organelles confirmed its coresidence with melanosomal markers. TPCN2 knockout by means of clustered regularly interspaced short palindromic repeat/CRISPR-associated 9 gene editing elicited a dramatic increase in pigment content in MNT-1 melanocytic cells. This effect was rescued by transient expression of TPC2-GFP. Consistently, siRNA-mediated knockdown of TPC2 also caused a substantial increase in melanin content in both MNT-1 cells and primary human melanocytes. Using a newly developed genetically encoded pH sensor targeted to melanosomes, we determined that the melanosome lumen in TPC2-KO MNT-1 cells and primary melanocytes subjected to TPC2 knockdown is less acidic than in control cells. Fluorescence and electron microscopy analysis revealed that TPC2-KO MNT-1 cells have significantly larger melanosomes than control cells, but the number of organelles is unchanged. TPC2 likely regulates melanosomes pH and size by mediating Ca(2+) release from the organelle, which is decreased in TPC2-KO MNT-1 cells, as determined with the Ca(2+) sensor tyrosinase-GCaMP6. Thus, our data show that TPC2 regulates pigmentation through two fundamental determinants of melanosome function: pH and size.

Expression of inhibitor of apoptosis proteins (IAPs) in rat granulosa cells during ovarian follicular development and atresia.

PubMed

Li, J; Kim, J M; Liston, P; Li, M; Miyazaki, T; Mackenzie, A E; Korneluk, R G; Tsang, B K

1998-03-01

The inhibitor of apoptosis proteins (IAPs) constitute a family of highly conserved apoptosis suppressor proteins that was originally identified in baculoviruses. Although IAP homologs have been recently identified and demonstrated to suppress apoptosis in mammalian cells, their expression and role during follicular development and atresia are unknown. The present study was conducted to address these questions. Using established in vivo models for the induction of follicular development and atresia in immature rats, it was possible to compare the immunolocalization of X-link inhibitor of apoptosis protein (Xiap) and human inhibitor of apoptosis protein-2 (Hiap-2), two members of the IAP family, at defined stages of follicular maturation and to relate the differences observed with those of follicular cell proliferation and apoptosis [as determined by proliferating cell nuclear antigen (PCNA) immunohistochemistry and in situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin end labeling (TUNEL), respectively]. In addition, granulosa cell DNA and proteins were assessed for apoptotic fragmentation by 3'-end labeling/agarose gel electrophoresis (DNA ladder) and Hiap-2 and Xiap protein content by Western blot analysis, respectively. Hiap-2 and Xiap expression in both granulosa and theca cells increased with follicular maturation, reaching maximal levels at the antral stage of development. The immunoreactivity for PCNA, Xiap, and Hiap-2 decreased markedly in atretic (TUNEL-positive) follicles at the small to medium sized antral stage of development, suggesting follicular atresia may be associated with decreased granulosa cell IAP protein content and decreased proliferation. Atresia was also associated with a change in the intracellular distribution of IAPs in granulosa cells. Biochemical analysis of DNA fragmentation (DNA ladder) in granulosa cells from preantral and early antral follicles indicates extensive apoptosis that was associated with minimal IAP protein content. Gonadotropin treatment increased Hiap-2 and Xiap protein content and suppressed apoptosis in granulosa cells, resulting in the development of follicles to the antral and preovulatory stages. In addition, gonadotropin withdrawal induced apoptotic DNA fragmentation in granulosa cells in early antral and antral follicles, which is accompanied by a marked decrease in Hiap-2 and Xiap expression. These data suggest that IAPs may be involved in the suppression of granulosa cell apoptosis by gonadotropin in small to medium-sized antral follicles and play an important role in determining the fate of the cells, and thus also the eventual follicular destiny (atresia vs. ovulation).

Improved genome recovery and integrated cell-size analyses of individual uncultured microbial cells and viral particles.

PubMed

Stepanauskas, Ramunas; Fergusson, Elizabeth A; Brown, Joseph; Poulton, Nicole J; Tupper, Ben; Labonté, Jessica M; Becraft, Eric D; Brown, Julia M; Pachiadaki, Maria G; Povilaitis, Tadas; Thompson, Brian P; Mascena, Corianna J; Bellows, Wendy K; Lubys, Arvydas

2017-07-20

Microbial single-cell genomics can be used to provide insights into the metabolic potential, interactions, and evolution of uncultured microorganisms. Here we present WGA-X, a method based on multiple displacement amplification of DNA that utilizes a thermostable mutant of the phi29 polymerase. WGA-X enhances genome recovery from individual microbial cells and viral particles while maintaining ease of use and scalability. The greatest improvements are observed when amplifying high G+C content templates, such as those belonging to the predominant bacteria in agricultural soils. By integrating WGA-X with calibrated index-cell sorting and high-throughput genomic sequencing, we are able to analyze genomic sequences and cell sizes of hundreds of individual, uncultured bacteria, archaea, protists, and viral particles, obtained directly from marine and soil samples, in a single experiment. This approach may find diverse applications in microbiology and in biomedical and forensic studies of humans and other multicellular organisms.Single-cell genomics can be used to study uncultured microorganisms. Here, Stepanauskas et al. present a method combining improved multiple displacement amplification and FACS, to obtain genomic sequences and cell size information from uncultivated microbial cells and viral particles in environmental samples.

Preparing nuclei from cells in monolayer cultures suitable for counting and for following synchronized cells through the cell cycle.

PubMed

Butler, W B

1984-08-15

A procedure is described for preparing nuclei from cells in monolayer culture so that they may be counted using an electronic particle counter. It takes only 10 to 15 min, and consists of swelling the cells in hypotonic buffer and then lysing them with the quaternary ammonium salt, ethylhexadecyldimethylammonium bromide. The cells are completely lysed, yielding a suspension of clean single nuclei which is stable, free of debris, and easily counted. The method was developed for a cell line of epithelial origin (MCF-7), which is often difficult to trypsinize to single cells. It works equally well at all cell densities up to and beyond confluence, and has been used with a variety of cells in culture, including 3T3 cells, bovine macrophages, rat mammary epithelial cells, mouse mammary tumor cell lines, and human fibroblasts. The size of the nuclei produced by this procedure is related to their DNA content, and the method is thus suitable for following cultures of synchronized cells through the cell cycle, and for performing differential counts of cells with substantial differences in DNA content.

Performance analysis of high efficiency InxGa1-xN/GaN intermediate band quantum dot solar cells

NASA Astrophysics Data System (ADS)

Chowdhury, Injamam Ul Islam; Sarker, Jith; Shifat, A. S. M. Zadid; Shuvro, Rezoan A.; Mitul, Abu Farzan

2018-06-01

In this subsistent fifth generation era, InxGa1-xN/GaN based materials have played an imperious role and become promising contestant in the modernistic fabrication technology because of some of their noteworthy attributes. On our way of illustrating the performance, the structure of InxGa1-xN/GaN quantum dot (QD) intermediate band solar cell (IBSC) is investigated by solving the Schrödinger equation in light of the Kronig-Penney model. In comparison with p-n homojunction and heterojunction solar cells, InxGa1-xN/GaN IBQD solar cell manifests larger power conversion efficiency (PCE). PCE strongly depends on position and width of the intermediate bands (IB). Position of IBs can be controlled by tuning the size of QDs and the Indium content of InxGa1-xN whereas, width of IB can be controlled by tuning the interdot distance. PCE can also be controlled by tuning the position of fermi energy bands as well as changing the doping concentration. In this work, maximum conversion efficiency is found approximately 63.2% for a certain QD size, interdot distance, Indium content and doping concentration.

Comparative analysis of cells and proteins of pumpkin plants for the control of fruit size.

PubMed

Nakata, Yumiko; Taniguchi, Go; Takazaki, Shinya; Oda-Ueda, Naoko; Miyahara, Kohji; Ohshima, Yasumi

2012-09-01

Common pumpkin plants (Cucurbita maxima) produce fruits of 1-2 kg size on the average, while special varieties of the same species called Atlantic Giant are known to produce a huge fruit up to several hundred kilograms. As an approach to determine the factors controlling the fruit size in C. maxima, we cultivated both AG and control common plants, and found that both the cell number and cell sizes were increased in a large fruit while DNA content of the cell did not change significantly. We also compared protein patterns in the leaves, stems, ripe and young fruits by two-dimensional (2D) gel electrophoresis, and identified those differentially expressed between them with mass spectroscopy. Based on these results, we suggest that factors in photosynthesis such as ribulose-bisphosphate carboxylase, glycolysis pathway enzymes, heat-shock proteins and ATP synthase play positive or negative roles in the growth of a pumpkin fruit. These results provide a step toward the development of plant biotechnology to control fruit size in the future. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Influence of Bravo fungicide applications on wood density and moisture content of Swiss needle cast affected Douglas-fir trees.

Treesearch

G.R. Johnson; Barbara L. Gartner; Doug Maguire; Alan Kanaskie

2003-01-01

Wood density, moisture content, tracheld width and cell wall size were examined in trees from plots that were sprayed for 5 years with chlorothalonil (Bravo ®) fungicide to reduce the impact of Swiss needle-cast (SNC) and from trees in adjacent unsprayed plots. The unsprayed (more heavily diseased) trees had significantly narrower sapwood, narrower growth tings, lower...

The quantal release at a neuro-neuronal synapse is regulated by the content of acetylcholine in the presynaptic cell.

PubMed

Poulain, B; Baux, G; Tauc, L

1986-01-01

Transmitter release was studied with respect to the presynaptic acetylcholine (ACh) content at a central identified inhibitory synapse (Cl- conductance) of Aplysia californica. Statistical analysis of the synaptic noise evoked by sustained depolarization of the presynaptic neuron allowed us to calculate the quantal parameters of the postsynaptic responses. Loading of the presynaptic neurone with injected ACh led to an increase in the postsynaptic responses whereas the calculated miniature postsynaptic current (MPSC) was unmodified. Destruction of choline by choline oxidase either applied extracellularly and coupled to intense stimulations of the presynaptic cell or injected into the presynaptic neuron induced a depression of the postsynaptic response although the amplitude of the calculated MPSC remained constant. As the size of the MPSC, i.e. the size of the quantum, did not change in these experiments, it was concluded that the presynaptic ACh content controls the number of quanta released by a given presynaptic depolarization. As additional evidence, effects of abrupt increase in tonicity of the external medium were studied. The observed transient enhancement of the quantal content of the postsynaptic response could be attributed to an increase in the presynaptic concentration of ACh, resulting from the reduction in cellular volume.

Brain glucose content in fetuses of ethanol-fed rats

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

Pullen, G.; Singh, S.P.; Snyder, A.K.

1986-03-01

The authors have previously demonstrated impaired placental glucose transfer and fetal hypoglycemia in association with ethanol ingestion by pregnant rats. The present study examines the relationship between glucose availability and fetal brain growth under the same conditions. Rats (EF) were fed ethanol (30% of caloric intake) in liquid diet throughout gestation. Controls received isocaloric diet without ethanol by pair-feeding (PF) or ad libitum (AF). On the 22nd day of gestation fetuses were obtained by cesarean section. Fetal brains were removed and freeze-clamped. Brain weight was significantly reduced (p < 0.001) by maternal ethanol ingestion (206 +/- 2, 212 +/- 4more » and 194 +/- 2 mg in AF, FP and EF fetuses respectively). Similarly, fetal brain glucose content was lower (p < 0.05) in the EF group (14.3 +/- 0.9 mmoles/g dry weight) than in the PF (18.6 +/- 1.0) or the AF (16.2 +/- 0.9) groups. The protein: DNA ratio, an indicator of cell size, correlated positively (r = 0.371, p < 0.005) with brain glucose content. In conclusion, maternal ethanol ingestion resulted in lower brain weight and reduced brain glucose content. Glucose availability may be a significant factor in the determination of cell size in the fetal rat brain.« less

Gold nanoparticles synthesis and biological activity estimation in vitro and in vivo.

PubMed

Rieznichenko, L S; Dybkova, S M; Gruzina, T G; Ulberg, Z R; Todor, I N; Lukyanova, N Yu; Shpyleva, S I; Chekhun, V F

2012-01-01

The aim of the work was the synthesis of gold nanoparticles (GNP) of different sizes and the estimation of their biological activity in vitro and in vivo. Water dispersions of gold nanoparticles of different sizes have been synthesized by Davis method and characterized by laser-correlation spectroscopy and transmission electron microscopy methods. The GNP interaction with tumor cells has been visualized by confocal microscopy method. The enzyme activity was determined by standard biochemical methods. GNP distribution and content in organs and tissues have been determined via atomic-absorption spectrometry method; genotoxic influence has been estimated by "Comet-assay" method. The GNP size-dependent accumulation in cultured U937 tumor cells and their ability to modulate U937 cell membrane Na(+),K(+)-АТР-ase activity value has been revealed in vitro. Using in vivo model of Guerin carcinoma it has been shown that GNP possess high affinity to tumor cells. Our results indicate the perspectives of use of the synthesized GNP water dispersions for cancer diagnostics and treatment. It's necessary to take into account a size-dependent biosafety level of nanoparticles.

In Vitro Cell Proliferation and Mechanical Behaviors Observed in Porous Zirconia Ceramics

PubMed Central

Li, Jing; Wang, Xiaobei; Lin, Yuanhua; Deng, Xuliang; Li, Ming; Nan, Cewen

2016-01-01

Zirconia ceramics with porous structure have been prepared by solid-state reaction using yttria-stabilized zirconia and stearic acid powders. Analysis of its microstructure and phase composition revealed that a pure zirconia phase can be obtained. Our results indicated that its porosity and pore size as well as the mechanical characteristics can be tuned by changing the content of stearic acid powder. The optimal porosity and pore size of zirconia ceramic samples can be effective for the increase of surface roughness, which results in higher cell proliferation values without destroying the mechanical properties. PMID:28773341

Diatom feeding across trophic guilds in tidal flat nematodes, and the importance of diatom cell size

NASA Astrophysics Data System (ADS)

Moens, Tom; Vafeiadou, Anna-Maria; De Geyter, Ellen; Vanormelingen, Pieter; Sabbe, Koen; De Troch, Marleen

2014-09-01

We examine the capacity of nematodes from three feeding types (deposit feeder, epistrate feeder, predator) to utilize microphytobenthos (MPB), and assess whether diatom cell size and consumer body size are important drivers of their feeding. We analyzed natural stable isotope ratios of carbon and nitrogen in abundant nematode genera and a variety of carbon sources at an estuarine intertidal flat. All nematodes had δ13C indicating that MPB is their major carbon source. δ15N, however, demonstrated that only one deposit and one epistrate feeder genus obtained most of their carbon from direct grazing on MPB, whereas other deposit feeders and predators obtained at least part of their carbon by predation on MPB grazers. We then performed a microcosm experiment in which equal cell numbers of each of three differently sized strains of the pennate diatom Seminavis were offered as food to four, one and one genera of deposit feeders, epistrate feeders and predators, respectively. Previous studies have shown that all but the epistrate feeder ingest whole diatoms, whereas the epistrate feeder pierces cells and sucks out their contents. Most genera showed markedly higher carbon absorption from medium and large cells than from small ones. When considering the number of cells consumed, however, none of the nematodes which ingest whole cells exhibited a clear preference for any specific diatom size. The epistrate feeder was the smallest nematode taxon considered here, yet it showed a marked preference for large cells. These results highlight that the feeding mechanism is much more important than consumer size as a driver of particle size selection in nematodes grazing MPB.

Planar-Structure Perovskite Solar Cells with Efficiency beyond 21.

PubMed

Jiang, Qi; Chu, Zema; Wang, Pengyang; Yang, Xiaolei; Liu, Heng; Wang, Ye; Yin, Zhigang; Wu, Jinliang; Zhang, Xingwang; You, Jingbi

2017-12-01

Low temperature solution processed planar-structure perovskite solar cells gain great attention recently, while their power conversions are still lower than that of high temperature mesoporous counterpart. Previous reports are mainly focused on perovskite morphology control and interface engineering to improve performance. Here, this study systematically investigates the effect of precise stoichiometry, especially the PbI 2 contents on device performance including efficiency, hysteresis and stability. This study finds that a moderate residual of PbI 2 can deliver stable and high efficiency of solar cells without hysteresis, while too much residual PbI 2 will lead to serious hysteresis and poor transit stability. Solar cells with the efficiencies of 21.6% in small size (0.0737 cm 2 ) and 20.1% in large size (1 cm 2 ) with moderate residual PbI 2 in perovskite layer are obtained. The certificated efficiency for small size shows the efficiency of 20.9%, which is the highest efficiency ever recorded in planar-structure perovskite solar cells, showing the planar-structure perovskite solar cells are very promising. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Morpho-functional parameters of nucleoli in polyploid mucous and albumen cells of salivary gland in the snail Succinea lauta].

PubMed

Anisimova, A A; Anisimov, A P

2005-01-01

Variation of some characteristics of nucleoli of polyploid mucous and albumen cells was examined in salivary glands of the snail Succinea lauta. The number, total area and Ag-protein content of nucleoli, and DNA content in each nucleus were estimated on squashed preparations incubated with AgNO3, decolorized and then Feulgen stained. The ultrastructure of nucleoli was studied by electron microscopy. Differentiated mucous cells had 4c-8c-16c-32c nuclei; albumen cells had 8c-16c-32c-64c-128c nuclei. The ultrastructure of nucleoli of the two cell types was essentially the same. Normally, a large fibrous to granular zone was observed in the nucleoli, without a clear distinction between fibrous and granular components. At the same time, aggregations of granular matter could be discerned at the periphery of nucleoli. No fibrous centers were observed. Occassionally, nucleolonema-like structures occurred. Normally each nucleolus contacted several chromosomes. On squashed preparations, the least size of nucleoli was 2-3 microm, and the largest size amounted to 14 microm in mucous cells, and to 50-80 microm in albumen cells. The number of nucleoli rose from 1-2 in tetraploid nuclei to 2-3 in 32c-nuclei, and to 5-7 in 128c-nuclei. The disparity between the ploidy levels of nuclei and the numbers of nucleoli may be due, presumably, to aggregation of chromosome NORs. The Ag-protein content in the nucleoli, and the total nucleolar area displayed a strong mutual correlation. Both parameters differed significantly by 1.5-2.2 times in mucous and albumen cells of the same ploidy level. Thus, in albumen and mucous cells the total Ag-protein content in octaploid nuclei was 3.3 and 2.2 relative units (r. u.), respectively. In 16c- and 32c-nuclei of albumen cells, it was 7.6 and 15.1 r. u.; and in the same nuclei of mucous cells--3.8 and 6.8 r. u., respectively. On the whole, in albumen cells, in the course of 4 endocycles (4c-128c), the total Ag-protein content increased by 17 times. Therefore, the mean multiplication factor for this parameter was found to be 2.05 per endocycle. In mucous cells, in the course of 3 endocycles (4c-32c), the total Ag-protein content increased by 5.2 times against 8 times expected, with the mean multiplication factor equal to 1.75 per endocycle. Thus, in the course of polyploidization of albumen and mucous cell nuclei, the gene dosage effect was fully pronounced in the former, and only partly in the latter. This differtence is due obviously to peculiarities of differentiation of the two cell types, in particular, to differences in the number of activated ribosomal genes.

Footprint area analysis of binary imaged Cupriavidus necator cells to study PHB production at balanced, transient, and limited growth conditions in a cascade process.

PubMed

Vadlja, Denis; Koller, Martin; Novak, Mario; Braunegg, Gerhart; Horvat, Predrag

2016-12-01

Statistical distribution of cell and poly[3-(R)-hydroxybutyrate] (PHB) granule size and number of granules per cell are investigated for PHB production in a five-stage cascade (5CSTR). Electron microscopic pictures of cells from individual cascade stages (R1-R5) were converted to binary pictures to visualize footprint areas for polyhydroxyalkanoate (PHA) and non-PHA biomass. Results for each stage were correlated to the corresponding experimentally determined kinetics (specific growth rate μ and specific productivity π). Log-normal distribution describes PHA granule size dissimilarity, whereas for R1 and R4, gamma distribution best reflects the situation. R1, devoted to balanced biomass synthesis, predominately contains cells with rather small granules, whereas with increasing residence time τ, maximum and average granule sizes by trend increase, approaching an upper limit determined by the cell's geometry. Generally, an increase of intracellular PHA content and ratio of granule to cell area slow down along the cascade. Further, the number of granules per cell decreases with increasing τ. Data for μ and π obtained by binary picture analysis correlate well with the experimental results. The work describes long-term continuous PHA production under balanced, transient, and nutrient-deficient conditions, as well as their reflection on the granules size, granule number, and cell structure on the microscopic level.

Chemistry and Biology in Femtoliter and Picoliter Volume Droplets

PubMed Central

Chiu, Daniel T.; Lorenz, Robert M.

2009-01-01

Conspectus The basic unit of any biological system is the cell, and malfunctions at the single-cell level can result in devastating diseases; in cancer metastasis, for example, a single cell seeds the formation of a distant tumor. Although tiny, a cell is a highly heterogeneous and compartmentalized structure: proteins, lipids, RNA, and small-molecule metabolites constantly traffic among intracellular organelles. Gaining detailed information about the spatiotemporal distribution of these biomolecules is crucial to our understanding of cellular function and dysfunction. To access this information, we need sensitive tools that are capable of extracting comprehensive biochemical information from single cells and subcellular organelles. In this Account, we outline our approach and highlight our progress towards mapping the spatiotemporal organization of information flow in single cells. Our technique is centered on the use of femtoliter- and picoliter-sized droplets as nanolabs for manipulating single cells and subcellular compartments. We have developed a single-cell nanosurgical technique for isolating select subcellular structures from live cells, a capability that is needed for the high-resolution manipulation and chemical analysis of single cells. Our microfluidic approaches for generating single femtoliter-sized droplets on demand include both pressure and electric field methods; we have also explored a design for the on-demand generation of multiple aqueous droplets to increase throughput. Droplet formation is only the first step in a sequence that requires manipulation, fusion, transport, and analysis. Optical approaches provide the most convenient and precise control over the formed droplets with our technology platform; we describe aqueous droplet manipulation with optical vortex traps, which enable the remarkable ability to dynamically “tune” the concentration of the contents. Integration of thermoelectric manipulations with these techniques affords further control. The amount of chemical information that can be gleaned from single cells and organelles is critically dependent on the methods available for analyzing droplet contents. We describe three techniques we have developed: (i) droplet encapsulation, rapid cell lysis, and fluorescence-based single-cell assays, (ii) physical sizing of the subcellular organelles and nanoparticles in droplets, and (iii) capillary electrophoresis (CE) analysis of droplet contents. For biological studies, we are working to integrate the different components of our technology into a robust, automated device; we are also addressing an anticipated need for higher throughput. With progress in these areas, we hope to cement our technique as a new tool for studying single cells and organelles with unprecedented molecular detail. PMID:19260732

Rupturing Giant Plasma Membrane Vesicles to Form Micron-sized Supported Cell Plasma Membranes with Native Transmembrane Proteins.

PubMed

Chiang, Po-Chieh; Tanady, Kevin; Huang, Ling-Ting; Chao, Ling

2017-11-09

Being able to directly obtain micron-sized cell blebs, giant plasma membrane vesicles (GPMVs), with native membrane proteins and deposit them on a planar support to form supported plasma membranes could allow the membrane proteins to be studied by various surface analytical tools in native-like bilayer environments. However, GPMVs do not easily rupture on conventional supports because of their high protein and cholesterol contents. Here, we demonstrate the possibility of using compression generated by the air-water interface to efficiently rupture GPMVs to form micron-sized supported membranes with native plasma membrane proteins. We demonstrated that not only lipid but also a native transmembrane protein in HeLa cells, Aquaporin 3 (AQP3), is mobile in the supported membrane platform. This convenient method for generating micron-sized supported membrane patches with mobile native transmembrane proteins could not only facilitate the study of membrane proteins by surface analytical tools, but could also enable us to use native membrane proteins for bio-sensing applications.

EMBRYONIC DEVELOPMENT AND A QUANTITATIVE MODEL OF PROGRAMMED DNA ELIMINATION IN MESOCYCLOPS EDAX (S. A. FORBES, 1891) (COPEPODA: CYCLOPOIDA)

PubMed Central

Clower, Michelle K.; Holub, Ashton S.; Smith, Rebecca T.; Wyngaard, Grace A.

2016-01-01

The highly programmed fragmentation of chromosomes and elimination of large amounts of nuclear DNA from the presomatic cell lineages (i.e., chromatin diminution), occurs in the embryos of the freshwater zooplankton Mesocyclops edax (S. A. Forbes, 1891) (Crustacea: Copepoda). The somatic genome is reorganized and reduced to a size five times smaller even though the germline genome remains intact. We present the first comprehensive, quantitative model of DNA content throughout embryogenesis in a copepod that possesses embryonic DNA elimination. We used densitometric image analysis to measure the DNA content of polar bodies, germline and somatic nuclei, and excised DNA “droplets.” We report: 1) variable DNA contents of polar bodies, some of which do not contain the amount corresponding to the haploid germline genome size; 2) presence of pronuclei in newly laid embryo sacs; 3) gonomeric chromosomes in the second to fourth cleavage divisions and in the primordial germ cell and primordial endoderm cell during the fifth cleavage division; 4) timing of early embryonic cell stages, elimination of DNA, and divisions of the primordial germ cell and primordial endoderm cell at 22°C; and 5) persistence of a portion of the excised DNA “droplets” throughout embryogenesis. DNA elimination is a trait that spans multiple embryonic stages and a knowledge of the timing and variability of the associated cytological events with DNA elimination will promote the study of the molecular mechanisms involved in this trait. We propose the “genome yolk hypothesis” as a functional explanation for the persistence of the eliminated DNA that might serve as a resource during postdiminution cleavage divisions. PMID:27857452

Suppression of Lymphocyte Functions by Plasma Exosomes Correlates with Disease Activity in Patients with Head and Neck Cancer.

PubMed

Ludwig, Sonja; Floros, Theofanis; Theodoraki, Marie-Nicole; Hong, Chang-Sook; Jackson, Edwin K; Lang, Stephan; Whiteside, Theresa L

2017-08-15

Purpose: Head and neck cancers (HNCs) often induce profound immunosuppression, which contributes to disease progression and interferes with immune-based therapies. Body fluids of patients with HNC are enriched in exosomes potentially engaged in negative regulation of antitumor immune responses. The presence and content of exosomes derived from plasma of patients with HNC are evaluated for the ability to induce immune dysfunction and influence disease activity. Experimental Design: Exosomes were isolated by size-exclusion chromatography from plasma of 38 patients with HNC and 14 healthy donors. Morphology, size, numbers, and protein and molecular contents of the recovered exosomes were determined. Coculture assays were performed to measure exosome-mediated effects on functions of normal human lymphocyte subsets and natural killer (NK) cells. The results were correlated with disease stage and activity. Results: The presence, quantity, and molecular content of isolated, plasma-derived exosomes discriminated patients with HNC with active disease (AD) from those with no evident disease (NED) after oncologic therapies. Exosomes of patients with AD were significantly more effective than exosomes of patients with NED in inducing apoptosis of CD8 + T cells, suppression of CD4 + T-cell proliferation, and upregulation of regulatory T-cell (Treg) suppressor functions (all at P < 0.05). Exosomes of patients with AD also downregulated NKG2D expression levels in NK cells. Conclusions: Exosomes in plasma of patients with HNC carry immunosuppressive molecules and interfere with functions of immune cells. Exosome-induced immune suppression correlates with disease activity in HNC, suggesting that plasma exosomes could be useful as biomarkers of HNC progression. Clin Cancer Res; 23(16); 4843-54. ©2017 AACR . ©2017 American Association for Cancer Research.

Modulation of mesenchymal stem cell behavior by nano- and micro-sized β-tricalcium phosphate particles in suspension and composite structures

NASA Astrophysics Data System (ADS)

Smoak, Mollie; Hogan, Katie; Kriegh, Lisa; Chen, Cong; Terrell, LeKeith B.; Qureshi, Ammar T.; Todd Monroe, W.; Gimble, Jeffrey M.; Hayes, Daniel J.

2015-04-01

Interest has grown in the use of microparticles and nanoparticles for modifying the mechanical and biological properties of synthetic bone composite structures. Micro- and nano-sized calcium phosphates are of interest for their osteoinductive behavior. Engineered composites incorporating polymers and ceramics, such as poly-l-lactic acid (PLLA) and beta-tricalcium phosphate (β-TCP), for bone tissue regeneration have been well investigated for their proliferative and osteoinductive abilities. Only limited research has been done to investigate the effects of different sizes of β-TCP particles on human mesenchymal stromal cell behavior. As such, the aim of this study was to investigate the modulations of human adipose-derived stem cell (hASCs) behavior within cell/particle and cell/composite systems as functions of particle size, concentration, and exposure time. The incorporation of nanoscale calcium phosphate resulted in improved mechanical properties and osteogenic behavior within the scaffold compared to the microscale calcium phosphate additives. Particle exposure results indicate that cytotoxicity on hASCs correlates inversely with particle size and increases with the increasing exposure time and particle concentration. Composites with increasing β-TCP content, whether microparticles or nanoparticles, were less toxic than colloidal micro- and nano-sized β-TCP particles directly supplied to hASCs. The difference in viability observed as a result of varying exposure route is likely related to the increased cell-particle interactions in the direct exposure compared to the particles becoming trapped within the scaffold/polymer matrix.

Effect of nanofiber content on bone regeneration of silk fibroin/poly(ε-caprolactone) nano/microfibrous composite scaffolds

PubMed Central

Kim, Beom Su; Park, Ko Eun; Kim, Min Hee; You, Hyung Keun; Lee, Jun; Park, Won Ho

2015-01-01

The broad application of electrospun nanofibrous scaffolds in tissue engineering is limited by their small pore size, which has a negative influence on cell migration. This disadvantage could be significantly improved through the combination of nano- and microfibrous structure. To accomplish this, different nano/microfibrous scaffolds were produced by hybrid electrospinning, combining solution electrospinning with melt electrospinning, while varying the content of the nanofiber. The morphology of the silk fibroin (SF)/poly(ε-caprolactone) (PCL) nano/microfibrous composite scaffolds was investigated with field-emission scanning electron microscopy, while the mechanical and pore properties were assessed by measurement of tensile strength and mercury porosimetry. To assay cell proliferation, cell viability, and infiltration ability, human mesenchymal stem cells were seeded on the SF/PCL nano/microfibrous composite scaffolds. From in vivo tests, it was found that the bone-regenerating ability of SF/PCL nano/microfibrous composite scaffolds was closely associated with the nanofiber content in the composite scaffolds. In conclusion, this approach of controlling the nanofiber content in SF/PCL nano/microfibrous composite scaffolds could be useful in the design of novel scaffolds for tissue engineering. PMID:25624762

Genome size evolution in relation to leaf strategy and metabolic rates revisited.

PubMed

Beaulieu, Jeremy M; Leitch, Ilia J; Knight, Charles A

2007-03-01

It has been proposed that having too much DNA may carry physiological consequences for plants. The strong correlation between DNA content, cell size and cell division rate could lead to predictable morphological variation in plants, including a negative relationship with leaf mass per unit area (LMA). In addition, the possible increased demand for resources in species with high DNA content may have downstream effects on maximal metabolic efficiency, including decreased metabolic rates. Tests were made for genome size-dependent variation in LMA and metabolic rates (mass-based photosynthetic rate and dark respiration rate) using our own measurements and data from a plant functional trait database (Glopnet). These associations were tested using two metrics of genome size: bulk DNA amount (2C DNA) and monoploid genome size (1Cx DNA). The data were analysed using an evolutionary framework that included a regression analysis and independent contrasts using a phylogenetic tree with estimates of molecular diversification times. A contribution index for the LMA data set was also calculated to determine which divergences have the greatest influence on the relationship between genome size and LMA. A significant negative association was found between bulk DNA amount and LMA in angiosperms. This was primarily a result of influential divergences that may represent early shifts in growth form. However, divergences in bulk DNA amount were positively associated with divergences in LMA, suggesting that the relationship may be indirect and mediated through other traits directly related to genome size. There was a significant negative association between genome size and metabolic rates that was driven by a basal divergence between angiosperms and gymnosperms; no significant independent contrast results were found. Therefore, it is concluded that genome size-dependent constraints acting on metabolic efficiency may not exist within seed plants.

A facile in vitro model to study rapid mineralization in bone tissues.

PubMed

Deegan, Anthony J; Aydin, Halil M; Hu, Bin; Konduru, Sandeep; Kuiper, Jan Herman; Yang, Ying

2014-09-16

Mineralization in bone tissue involves stepwise cell-cell and cell-ECM interaction. Regulation of osteoblast culture microenvironments can tailor osteoblast proliferation and mineralization rate, and the quality and/or quantity of the final calcified tissue. An in vitro model to investigate the influencing factors is highly required. We developed a facile in vitro model in which an osteoblast cell line and aggregate culture (through the modification of culture well surfaces) were used to mimic intramembranous bone mineralization. The effect of culture environments including culture duration (up to 72 hours for rapid mineralization study) and aggregates size (monolayer culture as control) on mineralization rate and mineral quantity/quality were examined by osteogenic gene expression (PCR) and mineral markers (histological staining, SEM-EDX and micro-CT). Two size aggregates (on average, large aggregates were 745 μm and small 79 μm) were obtained by the facile technique with high yield. Cells in aggregate culture generated visible and quantifiable mineralized matrix within 24 hours, whereas cells in monolayer failed to do so by 72 hours. The gene expression of important ECM molecules for bone formation including collagen type I, alkaline phosphatase, osteopontin and osteocalcin, varied temporally, differed between monolayer and aggregate cultures, and depended on aggregate size. Monolayer specimens stayed in a proliferation phase for the first 24 hours, and remained in matrix synthesis up to 72 hours; whereas the small aggregates were in the maturation phase for the first 24 and 48 hour cultures and then jumped to a mineralization phase at 72 hours. Large aggregates were in a mineralization phase at all these three time points and produced 36% larger bone nodules with a higher calcium content than those in the small aggregates after just 72 hours in culture. This study confirms that aggregate culture is sufficient to induce rapid mineralization and that aggregate size determines the mineralization rate. Mineral content depended on aggregate size and culture duration. Thus, our culture system may provide a good model to study regulation factors at different development phases of the osteoblastic lineage.

Leaf area and photosynthesis of newly emerged trifoliolate leaves are regulated by mature leaves in soybean.

PubMed

Wu, Yushan; Gong, Wanzhuo; Wang, Yangmei; Yong, Taiwen; Yang, Feng; Liu, Weigui; Wu, Xiaoling; Du, Junbo; Shu, Kai; Liu, Jiang; Liu, Chunyan; Yang, Wenyu

2018-03-29

Leaf anatomy and the stomatal development of developing leaves of plants have been shown to be regulated by the same light environment as that of mature leaves, but no report has yet been written on whether such a long-distance signal from mature leaves regulates the total leaf area of newly emerged leaves. To explore this question, we created an investigation in which we collected data on the leaf area, leaf mass per area (LMA), leaf anatomy, cell size, cell number, gas exchange and soluble sugar content of leaves from three soybean varieties grown under full sunlight (NS), shaded mature leaves (MS) or whole plants grown in shade (WS). Our results show that MS or WS cause a marked decline both in leaf area and LMA in newly developing leaves. Leaf anatomy also showed characteristics of shade leaves with decreased leaf thickness, palisade tissue thickness, sponge tissue thickness, cell size and cell numbers. In addition, in the MS and WS treatments, newly developed leaves exhibited lower net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (E), but higher carbon dioxide (CO 2 ) concentration in the intercellular space (Ci) than plants grown in full sunlight. Moreover, soluble sugar content was significantly decreased in newly developed leaves in MS and WS treatments. These results clearly indicate that (1) leaf area, leaf anatomical structure, and photosynthetic function of newly developing leaves are regulated by a systemic irradiance signal from mature leaves; (2) decreased cell size and cell number are the major cause of smaller and thinner leaves in shade; and (3) sugars could possibly act as candidate signal substances to regulate leaf area systemically.

HU content and dynamics in Escherichia coli during the cell cycle and at different growth rates.

PubMed

Abebe, Anteneh Hailu; Aranovich, Alexander; Fishov, Itzhak

2017-10-16

DNA-binding proteins play an important role in maintaining bacterial chromosome structure and functions. Heat-unstable (HU) histone-like protein is one of the most abundant of these proteins and participates in all major chromosome-related activities. Owing to its low sequence specificity, HU fusions with fluorescent proteins were used for general staining of the nucleoid, aiming to reveal its morphology and dynamics. We have exploited a single chromosomal copy of hupA-egfp fusion under the native promoter and used quantitative microscopy imaging to investigate the amount and dynamics of HUα in Escherichia coli cells. We found that in steady-state growing populations the cellular HUα content is proportional to the cell size, whereas its concentration is size independent. Single-cell live microscopy imaging confirmed that the amount of HUα exponentially increases during the cell cycle, but its concentration is maintained constant. This supports the existence of an auto-regulatory mechanism underlying the HUα cellular level, in addition to reflecting the gene copy number. Both the HUα amount and concentration strongly increase with the cell growth rate in different culture media. Unexpectedly, the HU/DNA stoichiometry also remarkably increases with the growth rate. This last finding may be attributed to a higher requirement for maintaining the chromosome structure in nucleoids with higher complexity. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Fabrication of macroporous cement scaffolds using PEG particles: In vitro evaluation with induced pluripotent stem cell-derived mesenchymal progenitors.

PubMed

Sladkova, Martina; Palmer, Michael; Öhman, Caroline; Alhaddad, Rawan Jaragh; Esmael, Asmaa; Engqvist, Håkan; de Peppo, Giuseppe Maria

2016-12-01

Calcium phosphate cements (CPCs) have been extensively used in reconstructive dentistry and orthopedics, but it is only recently that CPCs have been combined with stem cells to engineer biological substitutes with enhanced healing potential. In the present study, macroporous CPC scaffolds with defined composition were fabricated using an easily reproduced synthesis method, with minimal fabrication and processing steps. Scaffold pore size and porosity, essential for cell infiltration and tissue ingrowth, were tuned by varying the content and size of polyethylene glycol (PEG) particles, resulting in 9 groups with different architectural features. The scaffolds were characterized for chemical composition, porosity and mechanical properties, then tested in vitro with human mesenchymal progenitors derived from induced pluripotent stem cells (iPSC-MPs). Biomimetic decellularized bone scaffolds were used as reference material in this study. Our manufacturing process resulted in the formation of macroporous monetite scaffolds with no residual traces of PEG. The size and content of PEG particles was found to affect scaffold porosity, and thus mechanical properties. Irrespective of pore size and porosity, the CPC scaffolds fabricated in this study supported adhesion and viability of human iPSC-MPs similarly to decellularized bone scaffolds. However, the architectural features of the scaffolds were found to affect the expression of bone specific genes, suggesting that specific scaffold groups could be more suitable to direct human iPSC-MPs in vitro toward an osteoblastic phenotype. Our simplistic fabrication method allows rapid, inexpensive and reproducible construction of macroporous CPC scaffolds with tunable architecture for potential use in dental and orthopedic applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Morphology and viscoelastic properties of sealing materials based on EPDM rubber.

PubMed

Milić, J; Aroguz, A; Budinski-Simendić, J; Radicević, R; Prendzov, S

2008-12-01

In this applicative study, the ratio of active and inactive filler loadings was the prime factor for determining the dynamic-mechanical behaviour of ethylene-propylene-diene monomer rubbers. Scanning electron microscopy was used to study the structure of reinforced dense and microcellular elastomeric materials. The effects of filler and blowing agent content on the morphology of composites were investigated. Microcellular samples cured in salt bath show smaller cells and uniform cell size compared with samples cured in hot air. Dynamic-mechanical thermal analysis showed appreciable changes in the viscoelastic properties by increasing active filler content, which could enable tailoring the material properties to suit sealing applications.

A Content-Addressable Memory structure using quantum cells in nanotechnology with energy dissipation analysis

NASA Astrophysics Data System (ADS)

Sadoghifar, Ali; Heikalabad, Saeed Rasouli

2018-05-01

Quantum-dot cellular automata is one of the recent new technologies at the nanoscale that can be a suitable replacement for CMOS technology. The circuits constructed in QCA technology have desirable features such as low power consumption, high speed and small size. These features can be more distinct in memory structures. In this paper, we design a new structure for content addressable memory cell in QCA. For this purpose, first, a unique gate is introduced for mask operation in QCA and then this gate is used to improve the performance of CAM. These structures are evaluated with QCADesigner simulator.

The rapidly expanding universe of giant viruses: Mimivirus, Pandoravirus, Pithovirus and Mollivirus.

PubMed

Abergel, Chantal; Legendre, Matthieu; Claverie, Jean-Michel

2015-11-01

More than a century ago, the term 'virus' was introduced to describe infectious agents that are invisible by light microscopy and capable of passing through sterilizing filters. In addition to their extremely small size, most viruses have minimal genomes and gene contents, and rely almost entirely on host cell-encoded functions to multiply. Unexpectedly, four different families of eukaryotic 'giant viruses' have been discovered over the past 10 years with genome sizes, gene contents and particle dimensions overlapping with that of cellular microbes. Their ongoing analyses are challenging accepted ideas about the diversity, evolution and origin of DNA viruses. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Hypertrophy of proximal tubular epithelial cells induced by low pH in vitro is independent of ammoniagenesis.

PubMed

Bevington, A; Millwater, C J; Walls, J

1994-01-01

Metabolic acidosis can lead to tubular hypertrophy in vivo. This is thought to arise from stimulation of renal production of ammonia, a known hypertrophic agent. To examine this effect in vitro, confluent opossum (OK) proximal tubular epithelial cells were cultured at acidic pH (7.21 +/- 0.02) or at control pH (7.37 +/- 0.01) for 4 days. Protein content was 9% higher at acidic pH whereas DNA content was unaffected. The resulting increase in mean cell size (protein/DNA ratio) was 10% but correlated inversely with the mass of cells in control wells, varying from +48% at low cell mass to -14% at high cell mass. In contrast, low pH decreased 3H-thymidine incorporation by 9%. However, ammonia production was unaffected. These changes in protein/DNA ratio and 3H-thymidine incorporation cannot therefore be attributed to acid-induced ammoniagenesis and imply that low pH exerts a more direct effect on tubular cell growth than previously envisaged.

Subcellular Localization and Polymorphism of Bovine FABP4 in Bovine Intramuscular Adipocytes.

PubMed

Yonekura, Shinichi; Hirota, Shohei; Miyazaki, Honami; Tokutake, Yukako

2016-01-01

Fatty acid binding protein 4 (FABP4) I74 V, a gene polymorphism associated with unsaturated fatty acid contents, was discovered in Japanese Black cattle. Individuals with FABP4 I/I genotype contain a significantly high level of palmitoleic acid compared to those with FABP4 V/V genotype. It remains unknown how the FABP4 polymorphism leads to different palmitoleic acid contents. We overexpressed FABP4 of different genotypes in bovine intramuscular preadipocytes and examined whether the intracellular localization of FABP4 and the expression levels of lipid metabolism-related genes were different among cells expressing different genotypes. Nuclear localization was observed for the FABP4 V/V, while the FABP4 I/I almost did not. The cells expressing FABP4 of different genotypes were comparable in terms of the expression levels of genes involved in lipid metabolism. FABP4 I/I was localized in most of the lipid droplets 4 days after differentiation induction, whereas approximately 25% lipid droplet co-localized with FABP4 in cells expressing FABP4 V/V. The lipid droplet size increased when palmitoleic acid was added compared to the size observed when palmitic acid was added. These results suggest that lipid droplet enlargement caused by palmitoleic acid and genotype-dependent differences in the fatty acid transporting capacity underlie variations in palmitoleic acid content among FABP4 polymorphisms.

Identification of the Relationship between Oil Body Morphology and Oil Content by Microstructure Comparison Combining with QTL Analysis in Brassica napus

PubMed Central

Gu, Jianwei; Chao, Hongbo; Wang, Hao; Li, Yonghong; Li, Dianrong; Xiang, Jun; Gan, Jianping; Lu, Guangyuan; Zhang, Xuekun; Long, Yan; Li, Maoteng

2017-01-01

Oil bodies (OBs) are relatively simple but very important organelles comprising a matrix of triacylglycerol (TAG) surrounded by a phospholipid monolayer embedded and covered with unique proteins. The OB structure in Brassica napus with different oil content and the relationship between the oil content and the OB structure needs to be better understood. In this paper, the characteristics of OBs in the embryo of a series of B. napus materials with different oil content ranging from 34% to over 60% were studied. The results indicated that the OB size was significantly positively correlated with the oil content but was significantly negatively correlated with the glucosinolates and the protein content. Many genes associated with TAG synthesis, OB-membrane proteins, and the cell progress regulatory pathway were identified in the confidence interval of co-located QTLs for oil content, fatty acid (FA) compositions, and protein content. Our results suggested that the morphology of OBs might be directly controlled by the genes associated with OB-membrane proteins and indirectly controlled by the genes associated with TAG synthesis and cell progress regulatory pathway. PMID:28111582

Identification of the Relationship between Oil Body Morphology and Oil Content by Microstructure Comparison Combining with QTL Analysis in Brassica napus.

PubMed

Gu, Jianwei; Chao, Hongbo; Wang, Hao; Li, Yonghong; Li, Dianrong; Xiang, Jun; Gan, Jianping; Lu, Guangyuan; Zhang, Xuekun; Long, Yan; Li, Maoteng

2016-01-01

Oil bodies (OBs) are relatively simple but very important organelles comprising a matrix of triacylglycerol (TAG) surrounded by a phospholipid monolayer embedded and covered with unique proteins. The OB structure in Brassica napus with different oil content and the relationship between the oil content and the OB structure needs to be better understood. In this paper, the characteristics of OBs in the embryo of a series of B. napus materials with different oil content ranging from 34% to over 60% were studied. The results indicated that the OB size was significantly positively correlated with the oil content but was significantly negatively correlated with the glucosinolates and the protein content. Many genes associated with TAG synthesis, OB-membrane proteins, and the cell progress regulatory pathway were identified in the confidence interval of co-located QTLs for oil content, fatty acid (FA) compositions, and protein content. Our results suggested that the morphology of OBs might be directly controlled by the genes associated with OB-membrane proteins and indirectly controlled by the genes associated with TAG synthesis and cell progress regulatory pathway.

Effect of power on growth of nanocrystalline silicon films deposited by VHF PECVD technique for solar cell applications

NASA Astrophysics Data System (ADS)

Juneja, Sucheta; Verma, Payal; Savelyev, Dmitry A.; Khonina, Svetlana N.; Sudhakar, S.; Kumar, Sushil

2016-04-01

An investigation of the effect of power on the deposition of nanocrystalline silicon thin films were carried out using a gaseous mixture of silane and hydrogen in the 60MHz assisted VHF plasma enhanced chemical vapor deposition (PECVD) technique. The power was varied from 10 to 50 watt maintaining all other parameters constant. Corresponding layer properties w.r.t. material microstructure, optical, hydrogen content and electrical transport are studied in detail. The structural properties have been studied by Raman spectroscopy and x-ray diffraction (XRD). The presence of nano-sized crystals and their morphology have been investigated using atomic force microscopy (AFM). The role of bonded hydrogen content in the films have been studied from the results of Fourier transform infrared spectroscopy. It was observed from the results that with increase in power, crystalline volume fraction increases and crystallite size changes from 4 to 9 nm. The optical band gap varies from 1.7 to 2.1eV due to quantum confinement effect and which further can be explained with reduced hydrogen content. These striking features of nc-Si films can be used to fabricate stable thin film solar cells.

Coercivity temperature dependence of Sm2Co17-type sintered magnets with different cell and cell boundary microchemistry

NASA Astrophysics Data System (ADS)

Yu, Nengjun; Zhu, Minggang; Song, Liwei; Fang, Yikun; Song, KuiKui; Wang, Qiang; Li, Wei

2018-04-01

High maximum energy product ((BH)max) Sm(CobalFe0.18Cu0.07Zr0.03)7.7 magnet (type-A) and high temperature Sm(CobalFe0.1Cu0.09Zr0.03)7.2 magnet (type-B) were prepared by a traditional powder metallurgical technology. A record (BH)max of 98.7 kJ/m3 with a coercivity (Hcj) of 501.5 kA/m at 773 K was achieved for the type-B magnet, which is much higher than that of type-A magnet (63.7 kJ/m3). The microstructures of the magnets were revealed by high-resolution transmission electron microscope. The average cell size of the type-A and B magnet are 110 nm and 90 nm, respectively. Moreover, the type-B magnet shows a wider cell boundary than the type-A magnet. Additionally, the element distribution of the cell/cell boundary interfaces was measured by energy-dispersive spectroscopy. The cell phase of the type-A magnet contains a higher Fe content as about 17 at%, comparing with that of the type-B magnet (∼8.9 at%). On the other hand, the Cu content of the cell boundary phase is 18 at% almost twice higher than the type-B magnet (8.6 at%). Theoretical Hcj temperature dependence of these two kinds of magnets indicates that the lower Cu content in the cell boundary phase and the appropriate Fe content in the cell phase are the key factors for the high Hcj for the type-B magnet at elevated temperature.

Mycobacterial Cultures Contain Cell Size and Density Specific Sub-populations of Cells with Significant Differential Susceptibility to Antibiotics, Oxidative and Nitrite Stress

PubMed Central

Vijay, Srinivasan; Nair, Rashmi Ravindran; Sharan, Deepti; Jakkala, Kishor; Mukkayyan, Nagaraja; Swaminath, Sharmada; Pradhan, Atul; Joshi, Niranjan V.; Ajitkumar, Parthasarathi

2017-01-01

The present study shows the existence of two specific sub-populations of Mycobacterium smegmatis and Mycobacterium tuberculosis cells differing in size and density, in the mid-log phase (MLP) cultures, with significant differential susceptibility to antibiotic, oxidative, and nitrite stress. One of these sub-populations (~10% of the total population), contained short-sized cells (SCs) generated through highly-deviated asymmetric cell division (ACD) of normal/long-sized mother cells and symmetric cell divisions (SCD) of short-sized mother cells. The other sub-population (~90% of the total population) contained normal/long-sized cells (NCs). The SCs were acid-fast stainable and heat-susceptible, and contained high density of membrane vesicles (MVs, known to be lipid-rich) on their surface, while the NCs possessed negligible density of MVs on the surface, as revealed by scanning and transmission electron microscopy. Percoll density gradient fractionation of MLP cultures showed the SCs-enriched fraction (SCF) at lower density (probably indicating lipid-richness) and the NCs-enriched fraction (NCF) at higher density of percoll fractions. While live cell imaging showed that the SCs and the NCs could grow and divide to form colony on agarose pads, the SCF, and NCF cells could independently regenerate MLP populations in liquid and solid media, indicating their full genomic content and population regeneration potential. CFU based assays showed the SCF cells to be significantly more susceptible than NCF cells to a range of concentrations of rifampicin and isoniazid (antibiotic stress), H2O2 (oxidative stress),and acidified NaNO2 (nitrite stress). Live cell imaging showed significantly higher susceptibility of the SCs of SC-NC sister daughter cell pairs, formed from highly-deviated ACD of normal/long-sized mother cells, to rifampicin and H2O2, as compared to the sister daughter NCs, irrespective of their comparable growth rates. The SC-SC sister daughter cell pairs, formed from the SCDs of short-sized mother cells and having comparable growth rates, always showed comparable stress-susceptibility. These observations and the presence of M. tuberculosis SCs and NCs in pulmonary tuberculosis patients' sputum earlier reported by us imply a physiological role for the SCs and the NCs under the stress conditions. The plausible reasons for the higher stress susceptibility of SCs and lower stress susceptibility of NCs are discussed. PMID:28377757

High-Dose Nicotinamide Suppresses ROS Generation and Augments Population Expansion during CD8(+) T Cell Activation.

PubMed

Choi, Ho Jin; Jang, So-Young; Hwang, Eun Seong

2015-10-01

During T cell activation, mitochondrial content increases to meet the high energy demand of rapid cell proliferation. With this increase, the level of reactive oxygen species (ROS) also increases and causes the rapid apoptotic death of activated cells, thereby facilitating T cell homeostasis. Nicotinamide (NAM) has previously been shown to enhance mitochondria quality and extend the replicative life span of human fibroblasts. In this study, we examined the effect of NAM on CD8(+) T cell activation. NAM treatment attenuated the increase of mitochondrial content and ROS in T cells activated by CD3/CD28 antibodies. This was accompanied by an accelerated and higher-level clonal expansion resulting from attenuated apoptotic death but not increased division of the activated cells. Attenuation of ROS-triggered pro-apoptotic events and upregulation of Bcl-2 expression appeared to be involved. Although cells activated in the presence of NAM exhibited compromised cytokine gene expression, our results suggest a means to augment the size of T cell expansion during activation without consuming their limited replicative potential.

Cyclin D-Cdk4 is regulated by GATA-1 and required for megakaryocyte growth and polyploidization.

PubMed

Muntean, Andrew G; Pang, Liyan; Poncz, Mortimer; Dowdy, Steven F; Blobel, Gerd A; Crispino, John D

2007-06-15

Endomitosis is a unique form of cell cycle used by megakaryocytes, in which the latter stages of mitosis are bypassed so that the cell can increase its DNA content and size. Although several transcription factors, including GATA-1 and RUNX-1, have been implicated in this process, the link between transcription factors and polyploidization remains undefined. Here we show that GATA-1-deficient megakaryocytes, which display reduced size and polyploidization, express nearly 10-fold less cyclin D1 and 10-fold increased levels of p16 compared with their wild-type counterparts. We further demonstrate that cyclin D1 is a direct GATA-1 target in megakaryocytes, but not erythroid cells. Restoration of cyclin D1 expression, when accompanied by ectopic overexpression of its partner Cdk4, resulted in a dramatic increase in megakaryocyte size and DNA content. However, terminal differentiation was not rescued. Of note, polyploidization was only modestly reduced in cyclin D1-deficient mice, likely due to compensation by elevated cyclin D3 expression. Finally, consistent with an additional defect conferred by increased levels of p16, inhibition of cyclin D-Cdk4 complexes with a TAT-p16 fusion peptide significantly blocked polyploidization of wild-type megakaryocytes. Together, these data show that GATA-1 controls growth and polyploidization by regulating cyclin D-Cdk4 kinase activity.

Cyclin D–Cdk4 is regulated by GATA-1 and required for megakaryocyte growth and polyploidization

PubMed Central

Muntean, Andrew G.; Pang, Liyan; Poncz, Mortimer; Dowdy, Steven F.; Blobel, Gerd A.

2007-01-01

Endomitosis is a unique form of cell cycle used by megakaryocytes, in which the latter stages of mitosis are bypassed so that the cell can increase its DNA content and size. Although several transcription factors, including GATA-1 and RUNX-1, have been implicated in this process, the link between transcription factors and polyploidization remains undefined. Here we show that GATA-1–deficient megakaryocytes, which display reduced size and polyploidization, express nearly 10-fold less cyclin D1 and 10-fold increased levels of p16 compared with their wild-type counterparts. We further demonstrate that cyclin D1 is a direct GATA-1 target in megakaryocytes, but not erythroid cells. Restoration of cyclin D1 expression, when accompanied by ectopic overexpression of its partner Cdk4, resulted in a dramatic increase in megakaryocyte size and DNA content. However, terminal differentiation was not rescued. Of note, polyploidization was only modestly reduced in cyclin D1–deficient mice, likely due to compensation by elevated cyclin D3 expression. Finally, consistent with an additional defect conferred by increased levels of p16, inhibition of cyclin D-Cdk4 complexes with a TAT-p16 fusion peptide significantly blocked polyploidization of wild-type megakaryocytes. Together, these data show that GATA-1 controls growth and polyploidization by regulating cyclin D-Cdk4 kinase activity. PMID:17317855

Dynamics and Size of Cross-Linking-Induced Lipid Nanodomains in Model Membranes

PubMed Central

Štefl, Martin; Šachl, Radek; Humpolíčková, Jana; Cebecauer, Marek; Macháň, Radek; Kolářová, Marie; Johansson, Lennart B.-Å.; Hof, Martin

2012-01-01

Changes of membrane organization upon cross-linking of its components trigger cell signaling response to various exogenous factors. Cross-linking of raft gangliosides GM1 with cholera toxin (CTxB) was shown to cause microscopic phase separation in model membranes, and the CTxB-GM1 complexes forming a minimal lipid raft unit are the subject of ongoing cell membrane research. Yet, those subdiffraction sized rafts have never been described in terms of size and dynamics. By means of two-color z-scan fluorescence correlation spectroscopy, we show that the nanosized domains are formed in model membranes at lower sphingomyelin (Sph) content than needed for the large-scale phase separation and that the CTxB-GM1 complexes are confined in the domains poorly stabilized with Sph. Förster resonance energy transfer together with Monte Carlo modeling of the donor decay response reveal the domain radius of ∼8 nm, which increases at higher Sph content. We observed two types of domains behaving differently, which suggests a dual role of the cross-linker: first, local transient condensation of the GM1 molecules compensating for a lack of Sph and second, coalescence of existing nanodomains ending in large-scale phase separation. PMID:22824274

Titanium-containing zeolites and microporous molecular sieves as photovoltaic solar cells.

PubMed

Atienzar, Pedro; Valencia, Susana; Corma, Avelino; García, Hermenegildo

2007-05-14

Four titanium-containing zeolites and microporous molecular sieves differing on the crystal structure and particle size (Ti/Beta, Ti/Beta-60, TS-1 and ETS-10) are prepared, and their activity for solar cells after incorporating N3 (a commercially available ruthenium polypyridyl dye) is tested. All the zeolites exhibit photovoltaic activity, and the photoresponse is quite independent of the zeolite pore dimensions or particle size. The photoresponse increases with titanium content in the range 1-7% wt. In this way, cells are obtained that have open-circuit voltage Voc=560 mV and maximum short-circuit photocurrent density Isc=100 microA, measured for 1x1 cm2 surfaces with a solar simulator at 1000 W through and AM 1.5 filter. These values are promising and comparable to those obtained for current dye-sensitized titania solar cells.

[Effect of 2,3-butanedione monoxime on calcium paradox-induced heart injury in rats].

PubMed

Kong, Ling-Heng; Gu, Xiao-Ming; Su, Xing-Li; Sun, Na; Wei, Ming; Zhu, Juan-Xia; Chang, Pan; Zhou, Jing-Jun

2016-05-01

To investigate the Effect of 2,3-butanedione monoxime (BDM) on calcium paradox-induced heart injury and its underlying mechanisms. Thirty-two adult male SD rats were randomized into 4 groups, namely the control group, BDM treatment control group, calcium paradox group, and BDM treatment group. Isolated Sprague Dawley male rat hearts underwent Langendorff perfusion and the left ventricular pressure (LVP) and left ventricular end-diastolic pressure (LVEDP) were monitored. Left ventricular developed pressure (LVDP) was calculated to evaluate the myocardial performance. Lactate dehydrogenase (LDH) content in the coronary flow was determined. Triphenyltetrazolium chloride staining was used to measure the infarct size, and myocardial cell apoptosis was tested with TUNEL method. Western blotting was used to determine the expression of cleaved caspase-3 and cytochrome c. Compared with the control group, BDM at 20 mmol/L had no effect on cardiac performance, cell death, apoptotic index or the content of LDH, cleaved caspase-3 and cytochrome c at the end of perfusion under control conditions (P>0.05). Calcium paradox treatment significantly decreased the cardiac function and the level of LVDP and induced a larger infarct size (P<0.01), an increased myocardial apoptosis index (P<0.01), and up-regulated expressions of cleaved caspase-3 and cytochrome c (P<0.01). BDM (20 mmol/L) significantly attenuated these effects induced by calcium paradox, and markedly down-regulated the levels of LVEDP and LDH (P<0.01), lowered myocardial apoptosis index, decreased the content of cleaved caspase-3 and cytochrome c (P<0.01), increased LVDP, and reduced the infarct size (P<0.01). BDM suppresses cell apoptosis and contracture and improves heart function and cell survival in rat hearts exposed to calcium paradox, suggesting the value of BDM as an potential drug for myocardial ischemia reperfusion injur.

Interspecific correlation between red blood cell mitochondrial ROS production, cardiolipin content and longevity in birds.

PubMed

Delhaye, Jessica; Salamin, Nicolas; Roulin, Alexandre; Criscuolo, François; Bize, Pierre; Christe, Philippe

2016-12-01

Mitochondrial respiration releases reactive oxygen species (ROS) as by-products that can damage the soma and may in turn accelerate ageing. Hence, according to "the oxidative stress theory of ageing", longer-lived organisms may have evolved mechanisms that improve mitochondrial function, reduce ROS production and/or increase cell resistance to oxidative damage. Cardiolipin, an important mitochondrial inner-membrane phospholipid, has these properties by binding and stabilizing mitochondrial inner-membrane proteins. Here, we investigated whether ROS production, cardiolipin content and cell membrane resistance to oxidative attack in freshly collected red blood cells (RBCs) are associated with longevity (range 5-35 years) in 21 bird species belonging to seven Orders. After controlling for phylogeny, body size and oxygen consumption, variation in maximum longevity was significantly explained by mitochondrial ROS production and cardiolipin content, but not by membrane resistance to oxidative attack. RBCs of longer-lived species produced less ROS and contained more cardiolipin than RBCs of shorter-lived species did. These results support the oxidative stress theory of ageing and shed light on mitochondrial cardiolipin as an important factor linking ROS production to longevity.

Pancreatic Cancer Cell Exosome-Mediated Macrophage Reprogramming and the Role of MicroRNAs 155 and 125b2 Transfection using Nanoparticle Delivery Systems

PubMed Central

Su, Mei-Ju; Aldawsari, Hibah; Amiji, Mansoor

2016-01-01

Exosomes are nano-sized endosome-derived small intraluminal vesicles, which are important facilitators of intercellular communication by transporting contents, such as protein, mRNA, and microRNAs, between neighboring cells, such as in the tumor microenvironment. The purpose of this study was to understand the mechanisms of exosomes-mediated cellular communication between human pancreatic cancer (Panc-1) cells and macrophages (J771.A1) using a Transwell co-culture system. Following characterization of exosome-mediated cellular communication and pro-tumoral baseline M2 macrophage polarization, the Panc-1 cells were transfected with microRNA-155 (miR-155) and microRNA-125b-2 (miR-125b2) expressing plasmid DNA using hyaluronic acid-poly(ethylene imine)/hyaluronic acid-poly(ethylene glycol) (HA-PEI/HA-PEG) self-assembling nanoparticle-based non-viral vectors. Our results show that upon successful transfection of Panc-1 cells, the exosome content was altered leading to differential communication and reprogramming of the J774.A1 cells to an M1 phenotype. Based on these results, genetic therapies targeted towards selective manipulation of tumor cell-derived exosome content may be very promising for cancer therapy. PMID:27443190

Antimicrobial action of silver nitrate.

PubMed

Richards, R M

1981-01-01

Silver nitrate 3 mug/ml prevented the separation into two daughter cells of sensitive dividing cells of Pseudomonas aeruginosa growing in nutrient broth plus the chemical. Cell size of sensitive cells was increased and the cytoplasmic contents, cytoplasmic membrane and external cell envelope structures were all abnormal. P. aeruginosa cells grown in the presence of silver nitrate 9 mug/ml showed all these changes to a marked degree except inhibition of cell division was not observed. Silver nitrate (1.5 mug/ml) in distilled water inactivated bacteriophage T2 particles as determined by their infectivity to Escherichia coli B cultures. Lysozyme (50 mug/ml) reduced, and sodium chloride (0.9%) blocked this activity.

Immunochemical Investigations of Cell Surface Antigens of Anaerobic Bacteria

DTIC Science & Technology

1977-01-15

sterile cecal contents were included in all inocula, our data indicates * that cecal contents from germ free rats can be used in place of sterile cecal...The void volume of the column was estimated with blue dextran. Molecular size of the un- digested Pool 1 material was estimated using a PM-30 membrane...51) using bovine serum albumin as a standard. Total sugars were measured by the phenol-sulfuric acid method (52) using glucose as a standards

Detection of early changes in lung cell cytology by flow-systems analysis techniques, July 1--December 31, 1975

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

Steinkamp, J.A.; Ingram, M.; Hansen, K.M.

1976-03-01

This report summarizes results of preliminary experiments to demonstrate the feasibility of using automated flow-systems analysis in detecting early changes of respiratory epithelium exposed to physical and chemical agents associated with the by-products of nonnuclear energy production. The Syrian hamster was selected as the experimental test animal to begin investigation of the effects of toxic agents to cells of the respiratory tract. Since initiation of the program approximately six months ago, the goals have been acquisition of adequate numbers of exfoliated cells from the lung; adaptation of cytological techniques developed on human exfoliated gynecological samples to hamster lung epithelium formore » obtaining single-cell suspensions; utilization of existing cell staining methods to measure DNA content in lung cells; and analysis of DNA content and cell size. As the flow-system cell analysis technology is adapted to the measurement of exfoliated lung cells, rapid and quantitative determination of early changes in the physical and biochemical cellular properties will be attempted as a function of exposure to the toxic agents. (auth)« less

Thermoresponsive microgels containing trehalose as soft matrices for 3D cell culture.

PubMed

Burek, Małgorzata; Waśkiewicz, Sylwia; Lalik, Anna; Student, Sebastian; Bieg, Tadeusz; Wandzik, Ilona

2017-01-31

A series of thermoresponsive glycomicrogels with trehalose in the cross-links or with trehalose in the cross-links and as pending moieties was synthesized. These materials were obtained by surfactant-free precipitation copolymerization of N-isopropylacrylamide and various amounts of trehalose monomers. The resultant particles showed a spherical shape and a submicrometer hydrodynamic size with a narrow size distribution. At 25 °C, glycomicrogels in solutions with physiological ionic strength formed stable colloids, which further gelled upon heating to physiological temperature forming a macroscopic hydrogel with an interconnected porous structure. These extremely soft matrices with dynamic storage modulus in the range of 9-70 Pa were examined in 3D culture systems for HeLa cell culture in comparison to traditional 2D mode. They showed relatively low syneresis over time, especially when glycomicrogels with a high content of hydrophilic trehalose were used as building blocks. An incorporated pending trehalose composed of two α,α'-1,1'-linked d-glucose moieties was used with the intention of providing multivalent interactions with glucose transporters (GLUTs) expressed on the cell surface. A better cell viability was observed when a soft hydrogel with the highest content of trehalose and the lowest syneresis was used as a matrix compared to a 2D control assay.

NMDA receptor content of synapses in stratum radiatum of the hippocampal CA1 area.

PubMed

Racca, C; Stephenson, F A; Streit, P; Roberts, J D; Somogyi, P

2000-04-01

Glutamate receptors activated by NMDA (NMDARs) or AMPA (AMPARs) are clustered on dendritic spines of pyramidal cells. Both the AMPAR-mediated postsynaptic responses and the synaptic AMPAR immunoreactivity show a large intersynapse variability. Postsynaptic responses mediated by NMDARs show less variability. To assess the variability in NMDAR content and the extent of their coexistence with AMPARs in Schaffer collateral-commissural synapses of adult rat CA1 pyramidal cells, electron microscopic immunogold localization of receptors has been used. Immunoreactivity of NMDARs was detected in virtually all synapses on spines, but AMPARs were undetectable, on average, in 12% of synapses. A proportion of synapses had a very high AMPAR content relative to the mean content, resulting in a distribution more skewed toward larger values than that of NMDARs. The variability of synaptic NMDAR content [coefficient of variation (CV), 0.64-0.70] was much lower than that of the AMPAR content (CV, 1.17-1.45). Unlike the AMPAR content, the NMDAR content showed only a weak correlation with synapse size. As reported previously for AMPARs, the immunoreactivity of NMDARs was also associated with the spine apparatus within spines. The results demonstrate that the majority of the synapses made by CA3 pyramidal cells onto spines of CA1 pyramids express both NMDARs and AMPARs, but with variable ratios. A less-variable NMDAR content is accompanied by a wide variability of AMPAR content, indicating that the regulation of expression of the two receptors is not closely linked. These findings support reports that fast excitatory transmission at some of these synapses is mediated by activation mainly of NMDARs.

Nanostructured PEG-based hydrogels with tunable physical properties for gene delivery to human mesenchymal stem cells.

PubMed

Li, Yan; Yang, Chuan; Khan, Majad; Liu, Shaoqiong; Hedrick, James L; Yang, Yi-Yan; Ee, Pui-Lai R

2012-09-01

Effective delivery of DNA to direct cell behavior in a well defined three dimensional scaffold offers a superior approach in tissue engineering. In this study, we synthesized biodegradable nanostructured hydrogels with tunable physical properties for cell and gene delivery. The hydrogels were formed via Michael addition chemistry by reacting a four-arm acrylate-terminated PEG with a four-arm thiol-functionalized PEG. Nanosized micelles self-assembled from the amphiphilic PEG-b-polycarbonate diblock copolymer, having reactive end-groups, were chemically incorporated into the hydrogel networks at various contents. The use of Michael addition chemistry allows for in situ hydrogel formation under the physiological conditions. Mechanical property analysis of the hydrogels revealed a correlation between the content of micelles and the storage modulus of the hydrogels. Internal morphology of hydrogels was observed using a field emission scanning electron microscope, which showed that the number and/or size of the pores in the hydrogel increased with increasing micelle content due to reduced crosslinking degree. There exists an optimal micelle content for cell proliferation and gene transfection. MTT assays demonstrated the highest cell viability in the hydrogel with 20% micelles. The gene expression level in hMSCs in the hydrogel with 20% micelles was also significantly higher than that in the hydrogel without micelles. The enhanced cell viability and gene expression in the hydrogel with the optimized micelle content are likely attributed to the physical properties that provide a better environment for cell-matrix interactions. Therefore, incorporating micelles into the hydrogel is a good strategy to control cellular behavior in 3-D through changes in physical properties of the microenvironment. Copyright © 2012 Elsevier Ltd. All rights reserved.

Determination of the Thermal Properties of Sands as Affected by Water Content, Drainage/Wetting, and Porosity Conditions for Sands With Different Grain Sizes

NASA Astrophysics Data System (ADS)

Smits, K. M.; Sakaki, T.; Limsuwat, A.; Illangasekare, T. H.

2009-05-01

It is widely recognized that liquid water, water vapor and temperature movement in the subsurface near the land/atmosphere interface are strongly coupled, influencing many agricultural, biological and engineering applications such as irrigation practices, the assessment of contaminant transport and the detection of buried landmines. In these systems, a clear understanding of how variations in water content, soil drainage/wetting history, porosity conditions and grain size affect the soil's thermal behavior is needed, however, the consideration of all factors is rare as very few experimental data showing the effects of these variations are available. In this study, the effect of soil moisture, drainage/wetting history, and porosity on the thermal conductivity of sandy soils with different grain sizes was investigated. For this experimental investigation, several recent sensor based technologies were compiled into a Tempe cell modified to have a network of sampling ports, continuously monitoring water saturation, capillary pressure, temperature, and soil thermal properties. The water table was established at mid elevation of the cell and then lowered slowly. The initially saturated soil sample was subjected to slow drainage, wetting, and secondary drainage cycles. After liquid water drainage ceased, evaporation was induced at the surface to remove soil moisture from the sample to obtain thermal conductivity data below the residual saturation. For the test soils studied, thermal conductivity increased with increasing moisture content, soil density and grain size while thermal conductivity values were similar for soil drying/wetting behavior. Thermal properties measured in this study were then compared with independent estimates made using empirical models from literature. These soils will be used in a proposed set of experiments in intermediate scale test tanks to obtain data to validate methods and modeling tools used for landmine detection.

Imaging optical sensor arrays.

PubMed

Walt, David R

2002-10-01

Imaging optical fibres have been etched to prepare microwell arrays. These microwells have been loaded with sensing materials such as bead-based sensors and living cells to create high-density sensor arrays. The extremely small sizes and volumes of the wells enable high sensitivity and high information content sensing capabilities.

Fabrication and Cytotoxicity of Fucoidan-Cisplatin Nanoparticles for Macrophage and Tumor Cells.

PubMed

Hwang, Pai-An; Lin, Xiao-Zhen; Kuo, Ko-Liang; Hsu, Fu-Yin

2017-03-14

Fucoidan, an anionic, sulfated polysaccharide from brown seaweed, is known to exhibit antitumor and immunomodulatory functions. To develop an immune protection and chemotherapeutic agent, fucoidan-cisplatin nanoparticles (FCNPs) were designed. FCNPs were prepared by mixing cisplatin with fucoidan solution or fucoidan with cisplatin solution, followed by dialysis to remove trace elements. The nanoparticles, comprising 10 mg of fucoidan and 2 mg of cisplatin, which exhibited the highest cisplatin content and loading efficiency during the production process, were named as Fu100Cis20. The cisplatin content, cisplatin loading efficiency, nanoparticle size, and zeta potential of Fu100Cis20 were 18.9% ± 2.7%, 93.3% ± 7.8%, 181.2 ± 21.0 nm, and -67.4 ± 2.3 mV, respectively. Immune protection assay revealed that Fu100Cis20-treated RAW264.7 cells were protected from the cytotoxicity of cisplatin. Furthermore, antitumor assay indicated that Fu100Cis20-treated HCT-8 cells showed stronger cytotoxicity than those treated with cisplatin alone. These results suggested that fucoidan-based nanoparticles exhibited suitable particle size and high drug encapsulation, and that Fu100Cis20 has potential application in both immunotherapy and chemotherapy.

Regulation of Lipid Droplet Size in Mammary Epithelial Cells by Remodeling of Membrane Lipid Composition—A Potential Mechanism

PubMed Central

Cohen, Bat-Chen; Shamay, Avi; Argov-Argaman, Nurit

2015-01-01

Milk fat globule size is determined by the size of its precursors—intracellular lipid droplets—and is tightly associated with its composition. We examined the relationship between phospholipid composition of mammary epithelial cells and the size of both intracellular and secreted milk fat globules. Primary culture of mammary epithelial cells was cultured in medium without free fatty acids (control) or with 0.1 mM free capric, palmitic or oleic acid for 24 h. The amount and composition of the cellular lipids and the size of the lipid droplets were determined in the cells and medium. Mitochondrial quantity and expression levels of genes associated with mitochondrial biogenesis and polar lipid composition were determined. Cells cultured with oleic and palmitic acids contained similar quantities of triglycerides, 3.1- and 3.8-fold higher than in controls, respectively (P < 0.0001). When cultured with oleic acid, 22% of the cells contained large lipid droplets (>3 μm) and phosphatidylethanolamine concentration was higher by 23 and 63% compared with that in the control and palmitic acid treatments, respectively (P < 0.0001). In the presence of palmitic acid, only 4% of the cells contained large lipid droplets and the membrane phosphatidylcholine concentration was 22% and 16% higher than that in the control and oleic acid treatments, respectively (P < 0.0001). In the oleic acid treatment, approximately 40% of the lipid droplets were larger than 5 μm whereas in that of the palmitic acid treatment, only 16% of the droplets were in this size range. Triglyceride secretion in the oleic acid treatment was 2- and 12-fold higher compared with that in the palmitic acid and control treatments, respectively. Results imply that membrane composition of bovine mammary epithelial cells plays a role in controlling intracellular and secreted lipid droplets size, and that this process is not associated with cellular triglyceride content. PMID:25756421

Caustic esophageal injury by impaction of cell batteries.

PubMed

García Fernández, Francisco José; León Montañés, Rafael; Bozada Garcia, Juan Manuel

2016-12-01

The ingestion of cell batteries can cause serious complications (fistula, perforation or stenosis) at the esophageal level. The damage starts soon after ingestion (approximately 2 hours) and is directly related to the amount of time the battery is lodged in said location, the amount of electrical charge remaining in the battery, and the size of the battery itself. Injury is produced by the combination of electrochemical and chemical mechanisms and pressure necrosis. The ingestion of multiple cells and a size > = 20 mm are related with more severe and clinically significant outcomes. A female patient, 39 years old, with a history of previous suicide attempts, was admitted to the Emergency Room with chest pain and dysphagia after voluntary ingestion of 2 cell batteries. Two cell batteries are easily detected in a routine chest X-ray, presenting a characteristic double-ring shadow, or peripheral halo. Urgent oral endoscopy was performed 10 hours after ingestion, showing a greenish-gray lumpy magma-like consistency due to leakage of battery contents. The 2 batteries were sequentially removed with alligator-jaw forceps. After flushing and aspiration of the chemical material, a broad and circumferential injury with denudation of the mucosa and two deep ulcerations with necrosis were observed where the batteries had been. The batteries' seals were eroded, releasing chemical contents. Despite the severity of the injuries, the patient progressed favorably and there was no esophageal perforation. Esophageal impaction of cell batteries should always be considered an endoscopic urgency.

Impact of cell wall encapsulation of almonds on in vitro duodenal lipolysis.

PubMed

Grundy, Myriam M L; Wilde, Peter J; Butterworth, Peter J; Gray, Robert; Ellis, Peter R

2015-10-15

Although almonds have a high lipid content, their consumption is associated with reduced risk of cardiovascular disease. One explanation for this paradox could be limited bioaccessibility of almond lipids due to the cell wall matrix acting as a physical barrier to digestion in the upper gastrointestinal tract. We aimed to measure the rate and extent of lipolysis in an in vitro duodenum digestion model, using raw and roasted almond materials with potentially different degrees of bioaccessibility. The results revealed that a decrease in particle size led to an increased rate and extent of lipolysis. Particle size had a crucial impact on lipid bioaccessibility, since it is an indicator of the proportion of ruptured cells in the almond tissue. Separated almond cells with intact cell walls showed the lowest levels of digestibility. This study underlines the importance of the cell wall for modulating lipid uptake and hence the positive health benefits underlying almond consumption. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Size and Carbon Content of Sub-seafloor Microbial Cells

NASA Astrophysics Data System (ADS)

Braun, S.; Morono, Y.; Littmann, S.; Jørgensen, B. B.; Lomstein, B. A.

2015-12-01

Into the seafloor, a radical decline in nutrient and energy availability poses strong metabolic demands to any residing life. However, a sedimentary microbial ecosystem seems to maintain itself close to what we understand to be the energetic limit of life. Since a complex sediment matrix is interfering with the analysis of whole cells and sub-cellular compounds such as cell wall and membrane molecules, little is known about the physiological properties of cells in the deep biosphere. Here we focus on the size and carbon content of cells from a 90-m sediment drill core retrieved in October 2013 at Landsort Deep, Baltic Sea, in 437 meters water depth. To determine their shape and volume, cells were separated from the sediment matrix by multi-layer density centrifugation and visualized via fluorescence microscopy (FM), scanning electron microscopy (SEM), and stimulated emission depletion microscopy (STED). Total cell-carbon was calculated from amino acid-carbon, which was analyzed by high-performance liquid chromatography after cells had additionally been purified by fluorescence activated cell sorting (FACS). Cell-carbon turnover times were estimated using an amino acid racemization model that is based on the built-in molecular clock of aspartic acid, which due to racemization alternates between the D- and L-isomeric configurations over timescales of thousands of years at low in-situ temperatures (≈4˚C). We find that the majority of microbial cells in the sediment have coccoid or rod-shaped morphology, and that absolute values for cell volume are strongly dependent on the method used, spanning three orders of magnitude from approximately 0.001 to 1 µm3 for both coccoid and rod-shaped cells. From the surface to the deepest sample measured (≈60 mbsf), cell volume decreases by an order of magnitude, and carbon content is in the lower range (<20 fg C cell-1) of what has been reported in the literature as conversion factors. Cell-carbon is turned over approximately every 50-600 years, and total carbon oxidation rates decrease from ≈3400 to <60 nmol cm-3 yr-1 with depth, as inferred from amino acid racemization modeling. Given the large extent of marine sediments on Earth, our data will shed light on the energetic limits of life on our planet and will be important for estimating global biomass budgets.

TPC2 controls pigmentation by regulating melanosome pH and size

PubMed Central

Ambrosio, Andrea L.; Boyle, Judith A.; Aradi, Al E.; Christian, Keith A.; Di Pietro, Santiago M.

2016-01-01

Melanin is responsible for pigmentation of skin and hair and is synthesized in a specialized organelle, the melanosome, in melanocytes. A genome-wide association study revealed that the two pore segment channel 2 (TPCN2) gene is strongly linked to pigmentation variations. TPCN2 encodes the two-pore channel 2 (TPC2) protein, a cation channel. Nevertheless, how TPC2 regulates pigmentation remains unknown. Here, we show that TPC2 is expressed in melanocytes and localizes to the melanosome-limiting membrane and, to a lesser extent, to endolysosomal compartments by confocal fluorescence and immunogold electron microscopy. Immunomagnetic isolation of TPC2-containing organelles confirmed its coresidence with melanosomal markers. TPCN2 knockout by means of clustered regularly interspaced short palindromic repeat/CRISPR-associated 9 gene editing elicited a dramatic increase in pigment content in MNT-1 melanocytic cells. This effect was rescued by transient expression of TPC2-GFP. Consistently, siRNA-mediated knockdown of TPC2 also caused a substantial increase in melanin content in both MNT-1 cells and primary human melanocytes. Using a newly developed genetically encoded pH sensor targeted to melanosomes, we determined that the melanosome lumen in TPC2-KO MNT-1 cells and primary melanocytes subjected to TPC2 knockdown is less acidic than in control cells. Fluorescence and electron microscopy analysis revealed that TPC2-KO MNT-1 cells have significantly larger melanosomes than control cells, but the number of organelles is unchanged. TPC2 likely regulates melanosomes pH and size by mediating Ca2+ release from the organelle, which is decreased in TPC2-KO MNT-1 cells, as determined with the Ca2+ sensor tyrosinase-GCaMP6. Thus, our data show that TPC2 regulates pigmentation through two fundamental determinants of melanosome function: pH and size. PMID:27140606

Toward Interactive Mobile Synchronous Learning Environment with Context-Awareness Service

ERIC Educational Resources Information Center

Huang, Yueh-Min; Kuo, Yen-Hung; Lin, Yen-Ting; Cheng, Shu-Chen

2008-01-01

Mobile synchronous learning is a new challenge in the e-learning domain. While popular mobile communication devices, such as cell phones, cannot directly accommodate traditional synchronous content due to the major limitation of display size, other constraints also restrict convenient interactions while using mobile devices in a synchronous…

A novel ternary content addressable memory design based on resistive random access memory with high intensity and low search energy

NASA Astrophysics Data System (ADS)

Han, Runze; Shen, Wensheng; Huang, Peng; Zhou, Zheng; Liu, Lifeng; Liu, Xiaoyan; Kang, Jinfeng

2018-04-01

A novel ternary content addressable memory (TCAM) design based on resistive random access memory (RRAM) is presented. Each TCAM cell consists of two parallel RRAM to both store and search for ternary data. The cell size of the proposed design is 8F2, enable a ∼60× cell area reduction compared with the conventional static random access memory (SRAM) based implementation. Simulation results also show that the search delay and energy consumption of the proposed design at the 64-bit word search are 2 ps and 0.18 fJ/bit/search respectively at 22 nm technology node, where significant improvements are achieved compared to previous works. The desired characteristics of RRAM for implementation of the high performance TCAM search chip are also discussed.

Incretin Receptor Null Mice Reveal Key Role of GLP-1 but Not GIP in Pancreatic Beta Cell Adaptation to Pregnancy

PubMed Central

Moffett, R. Charlotte; Vasu, Srividya; Thorens, Bernard; Drucker, Daniel J.; Flatt, Peter R.

2014-01-01

Islet adaptations to pregnancy were explored in C57BL6/J mice lacking functional receptors for glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP). Pregnant wild type mice and GIPRKO mice exhibited marked increases in islet and beta cell area, numbers of medium/large sized islets, with positive effects on Ki67/Tunel ratio favouring beta cell growth and enhanced pancreatic insulin content. Alpha cell area and glucagon content were unchanged but prohormone convertases PC2 and PC1/3 together with significant amounts of GLP-1 and GIP were detected in alpha cells. Knockout of GLP-1R abolished these islet adaptations and paradoxically decreased pancreatic insulin, GLP-1 and GIP. This was associated with abolition of normal pregnancy-induced increases in plasma GIP, L-cell numbers, and intestinal GIP and GLP-1 stores. These data indicate that GLP-1 but not GIP is a key mediator of beta cell mass expansion and related adaptations in pregnancy, triggered in part by generation of intra-islet GLP-1. PMID:24927416

Micro-Nanostructures of Cellulose-Collagen for Critical Sized Bone Defect Healing.

PubMed

Aravamudhan, Aja; Ramos, Daisy M; Nip, Jonathan; Kalajzic, Ivo; Kumbar, Sangamesh G

2018-02-01

Bone tissue engineering strategies utilize biodegradable polymeric matrices alone or in combination with cells and factors to provide mechanical support to bone, while promoting cell proliferation, differentiation, and tissue ingrowth. The performance of mechanically competent, micro-nanostructured polymeric matrices, in combination with bone marrow stromal cells (BMSCs), is evaluated in a critical sized bone defect. Cellulose acetate (CA) is used to fabricate a porous microstructured matrix. Type I collagen is then allowed to self-assemble on these microstructures to create a natural polymer-based, micro-nanostructured matrix (CAc). Poly (lactic-co-glycolic acid) matrices with identical microstructures serve as controls. Significantly higher number of implanted host cells are distributed in the natural polymer based micro-nanostructures with greater bone density and more uniform cell distribution. Additionally, a twofold increase in collagen content is observed with natural polymer based scaffolds. This study establishes the benefits of natural polymer derived micro-nanostructures in combination with donor derived BMSCs to repair and regenerate critical sized bone defects. Natural polymer based materials with mechanically competent micro-nanostructures may serve as an alternative material platform for bone regeneration. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The effect of clinorotation on structural and functional organization of assimilative tissues, cells and growth regulator activity in orchids of different age

NASA Astrophysics Data System (ADS)

Cherevchenko, T.; Zaimenko, N.; Sitnyanska, N.; Majko, T.; Grishko, M. M.

Ultrastructural analyses of assimilative tissues of the orchids, Cymbidium hybridum and Doritis pulcherrima, show that, in plants of different age, chloroplasts differ in structure and stage of membrane system development. Variability was found in the number, size and electron density of plastoglobuli, and in the orientation and length of thylakoid membranes. We consider significant the increase of the plastoglobuli which completely fill the stroma of chloroplasts in cells of old leaves and, under conditions of clinorotation (using a horizontal clinostat at 3 r.p.m.), are able to block membrane function. In the early stages of orchid plant development, the content of substances with auxin-like activity (as judged by bioassay) in the leaves was low, but increased with age. Clinorotation resulted in a sharp decrease of their content. There was a concomitant increase in the content of growth inhibitors of a phenolic nature.

Effects of varying particle size of forage on digestion and chewing behavior of dairy heifers.

PubMed

Jaster, E H; Murphy, M R

1983-04-01

Eighteen Holstein heifers were fed long and chopped coarse and fine alfalfa hay ad libitum to evaluate effects of physical form on digestion and chemical composition of feed and fecal particles and to examine the applicability of a sinusoidal model to chewing behavior. Recordings of jaw movement were divided into 1-h segments for analysis. Least square mean size of fecal particles from coarse and finely chopped diets were 290 and 297 micrometers as compared to 227 micrometers on long hay. Intakes of dry matter were greater an digestibilities lower for chopped as compared to long hay. Crude protein content of separated feed and fecal particles increased as particle size decreased. Neural and acid detergent fiber concentrations decreased in feed and feces with decreasing particle size. Lignin content of feed particles decreased as particle size decreased, whereas for fecal particles lignin as a percent of cell wall followed a "U" shaped pattern of declining then increasing as size decreased. Patterns were sinusoidal for eating and ruminating long and chopped hays and total chewing (eating and ruminating) of long hay. Our results suggest a gradual effect on chemical degradation and physical detrition of digesta particles and chewing behavior as forage particle size decreased.

Role of platinum DNA damage-induced transcriptional inhibition in chemotherapy-induced neuronal atrophy and peripheral neurotoxicity.

PubMed

Yan, Fang; Liu, Johnson J; Ip, Virginia; Jamieson, Stephen M F; McKeage, Mark J

2015-12-01

Platinum-based anticancer drugs cause peripheral neurotoxicity by damaging sensory neurons within the dorsal root ganglia (DRG), but the mechanisms are incompletely understood. The roles of platinum DNA binding, transcription inhibition and altered cell size were investigated in primary cultures of rat DRG cells. Click chemistry quantitative fluorescence imaging of RNA-incorporated 5-ethynyluridine showed high, but wide ranging, global levels of transcription in individual neurons that correlated with their cell body size. Treatment with platinum drugs reduced neuronal transcription and cell body size to an extent that corresponded to the amount of preceding platinum DNA binding, but without any loss of neuronal cells. The effects of platinum drugs on neuronal transcription and cell body size were inhibited by blocking platinum DNA binding with sodium thiosulfate, and mimicked by treatment with a model transcriptional inhibitor, actinomycin D. In vivo oxaliplatin treatment depleted the total RNA content of DRG tissue concurrently with altering DRG neuronal size. These findings point to a mechanism of chemotherapy-induced peripheral neurotoxicity, whereby platinum DNA damage induces global transcriptional arrest leading in turn to neuronal atrophy. DRG neurons may be particularly vulnerable to this mechanism of toxicity because of their requirements for high basal levels of global transcriptional activity. Findings point to a new stepwise mechanism of chemotherapy-induced peripheral neurotoxicity, whereby platinum DNA damage induces global transcriptional arrest leading in turn to neuronal atrophy. Dorsal root ganglion neurons may be particularly vulnerable to this neurotoxicity because of their high global transcriptional outputs, demonstrated in this study by click chemistry quantitative fluorescence imaging. © 2015 International Society for Neurochemistry.

Evaluation of ploidy level and endoreduplication in carnation (Dianthus spp.).

PubMed

Agulló-Antón, María Ángeles; Olmos, Enrique; Pérez-Pérez, José Manuel; Acosta, Manuel

2013-03-01

Carnation (Dianthus caryophyllus L.) is one of the fifth most important ornamental species worldwide. Many desirable plant characteristics, such as big size, adaptation under stress, and intra or interspecific hybridization capability, are dependent on plant ploidy level. We optimized a quick flow cytometry method for DNA content determination in wild and cultivated carnation samples that allowed a systematic evaluation of ploidy levels in Dianthus species. The DNA content of different carnation cultivars and wild Dianthus species was determined using internal reference standards. The precise characterization of ploidy, endoreduplication and C-value of D. caryophyllus 'Master' makes it a suitable standard cultivar for ploidy level determination in other carnation cultivars. Mixoploidy was rigorously characterized in different regions of several organs from D. caryophyllus 'Master', which combined with a detailed morphological description suggested some distinctive developmental traits of this species. Both the number of endoreduplication cycles and the proportion of endopolyploid cells were highly variable in the petals among the cultivars studied, differently to the values found in leaves. Our results suggest a positive correlation between ploidy, cell size and petal size in cultivated carnation, which should be considered in breeding programs aimed to obtain new varieties with large flowers. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Sodium alginate ameliorates indomethacin-induced gastrointestinal mucosal injury via inhibiting translocation in rats

PubMed Central

Yamamoto, Atsuki; Itoh, Tomokazu; Nasu, Reishi; Nishida, Ryuichi

2014-01-01

AIM: To investigate the effects of sodium alginate (AL-Na) on indomethacin-induced small intestinal lesions in rats. METHODS: Gastric injury was assessed by measuring ulcerated legions 4 h after indomethacin (25 mg/kg) administration. Small intestinal injury was assessed by measuring ulcerated legions 24 h after indomethacin (10 mg/kg) administration. AL-Na and rebamipide were orally administered. Myeloperoxidase activity in the stomach and intestine were measured. Microvascular permeability, superoxide dismutase content, glutathione peroxidase activity, catalase activity, red blood cell count, white blood cell count, mucin content and enterobacterial count in the small intestine were measured. RESULTS: AL-Na significantly reduced indomethacin-induced ulcer size and myeloperoxidase activity in the stomach and small intestine. AL-Na prevented increases in microvascular permeability, superoxide dismutase content, glutathione peroxidase activity and catalase activity in small intestinal injury induced by indomethacin. AL-Na also prevented decreases in red blood cells and white blood cells in small intestinal injury induced by indomethacin. Moreover, AL-Na suppressed mucin depletion by indomethacin and inhibited infiltration of enterobacteria into the small intestine. CONCLUSION: These results indicate that AL-Na ameliorates non-steroidal anti-inflammatory drug-induced small intestinal enteritis via bacterial translocation. PMID:24627600

Comparison between PCL/hydroxyapatite (HA) and PCL/halloysite nanotube (HNT) composite scaffolds prepared by co-extrusion and gas foaming.

PubMed

Jing, Xin; Mi, Hao-Yang; Turng, Lih-Sheng

2017-03-01

In this work, three-dimensional poly(caprolactone) (PCL) tissue engineering scaffolds were prepared by co-extrusion and gas foaming. Biocompatible hydroxyapatite (HA) and halloysite nanotubes (HNT) were added to the polymer matrix to enhance the mechanical properties and bioactivity of the composite scaffolds. The effects of HA and HNT on the rheological behavior, microstructure, and mechanical properties of the composite scaffolds were systematically compared. It was found that the HNT improved viscosity more significantly than HA, and reduced the pore size of scaffolds, while the mechanical performance of PCL/HNT scaffolds was higher than PCL/HA scaffolds with the same filler content. Human mesenchymal stem cells (hMSCs) were used as the cell model to compare the biological properties of two composite scaffolds. The results demonstrated that cells could survive on all scaffolds, and showed a more flourishing living state on the composite scaffolds. The cell differentiation for 5% HA and 1% HNT scaffolds were significantly higher than other scaffolds, while the differentiation of 5% HNT scaffolds was lower than that of 1% HNT scaffolds mainly because of the reduced pore size and pore interconnectivity. Therefore, this study suggested that, with proper filler content and control of microstructure through processing, HNT could be a suitable substitute for HA for bone tissue engineering to reduce the cost and improve mechanical performance. Copyright © 2016. Published by Elsevier B.V.

Different degrees of somatotroph ablation compromise pituitary growth hormone cell network structure and other pituitary endocrine cell types.

PubMed

Waite, Eleanor; Lafont, Chrystel; Carmignac, Danielle; Chauvet, Norbert; Coutry, Nathalie; Christian, Helen; Robinson, Iain; Mollard, Patrice; Le Tissier, Paul

2010-01-01

We have generated transgenic mice with somatotroph-specific expression of a modified influenza virus ion channel, (H37A)M2, leading to ablation of GH cells with three levels of severity, dependent on transgene copy number. GH-M2(low) mice grow normally and have normal-size pituitaries but 40-50% reduction in pituitary GH content in adult animals. GH-M2(med) mice have male-specific transient growth retardation and a reduction in pituitary GH content by 75% at 42 d and 97% by 100 d. GH-M2(high) mice are severely dwarfed with undetectable pituitary GH. The GH secretory response of GH-M2(low) and GH-M2(med) mice to GH-releasing peptide-6 and GHRH was markedly attenuated. The content of other pituitary hormones was affected depending on transgene copy number: no effect in GH-M2(low) mice, prolactin and TSH reduced in GH-M2(med) mice, and all hormones reduced in GH-M2(high) mice. The effect on non-GH hormone content was associated with increased macrophage invasion of the pituitary. Somatotroph ablation affected GH cell network organization with limited disruption in GH-M2(low) mice but more severe disruption in GH-M2(med) mice. The remaining somatotrophs formed tight clusters after puberty, which contrasts with GHRH-M2 mice with a secondary reduction in somatotrophs that do not form clusters. A reduction in pituitary beta-catenin staining was correlated with GH-M2 transgene copy number, suggesting M2 expression has an effect on cell-cell communication in somatotrophs and other pituitary cell types. GH-M2 transgenic mice demonstrate that differing degrees of somatotroph ablation lead to correlated secondary effects on cell populations and cellular network organization.

[Exploratory study on the micro-remodeling of dermal tissue].

PubMed

Jiang, Yu-zhi; Ding, Gui-fu; Lu, Shu-liang

2009-10-01

To explore the effect of three-dimensional structure of dermal matrix on biological behavior of fibroblasts (Fb) in the microcosmic perspective. The three-dimensional structure of dermal tissue was analyzed by plane geometric and trigonometric function. Microdots structure array with cell adhesion effect was designed by computer-assisted design software according to the adhesive and non-adhesive components of dermal tissue. Four sizes (8 microm x 3 microm, space 6 microm; 16 microm x 3 microm, space 6 microm; 16 microm x 5 microm, space 8 microm; 20 microm x 3 microm, space 2 microm) of micropier grid used for cell culture (MPGCC) with cell-adhesive microdots, built up with micro-pattern printing and molecule self-assembly method were used to culture dermal Fb. Fb cultured with cell culture matrix without micropier grid was set up as control. The expression of skeleton protein (alpha-SMA) of Fb, cell viability and cell secretion were detected with immunohistochemistry, fluorescent immunohistochemistry, MTT test and the hydroxyproline content assay. The three-dimensional structure of dermal tissue could be simulated by MPGCC as shown in arithmetic analysis. Compared with those of control group [(12 +/- 3)% and (0.53 +/- 0.03) microg/mg, (0.35 +/- 0.04)], the expression of alpha-SMA [(49 +/- 3)%, (61 +/- 3)%, (47 +/- 4)%, (51 +/- 3)%] and the content of hydroxyproline [(0.95 +/- 0.04), (0.87 +/- 0.03), (0.81 +/- 0.03), (0.77 +/- 0.03) microg/mg] were increased significantly (P < 0.05), the cell viability of Fb (0.12 +/- 0.03, 0.13 +/- 0.04, 0.14 +/- 0.03, 0.19 +/- 0.03) cultured in MPGCC was decreased significantly (P < 0.05). When the parameters of micropier grid were changed, the expression of alpha-SMA, the cell viability and the content of hydroxyproline of Fb cultured in four sizes of MPGCC were also significantly changed as compared with one another (P < 0.05). MPGCC may be the basic functional unit of dermal template, or unit of dermal template to call. Different three-dimensional circumstances for dermal tissue can result in different template effect and wound healing condition.

Cupriavidus taiwanensis bacteroids in Mimosa pudica Indeterminate nodules are not terminally differentiated.

PubMed

Marchetti, Marta; Catrice, Olivier; Batut, Jacques; Masson-Boivin, Catherine

2011-03-01

The beta-rhizobium Cupriavidus taiwanensis forms indeterminate nodules on Mimosa pudica. C. taiwanensis bacteroids resemble free-living bacteria in terms of genomic DNA content, cell size, membrane permeability, and viability, in contrast to bacteroids in indeterminate nodules of the galegoid clade. Bacteroid differentiation is thus unrelated to nodule ontogeny.

Mucoadhesive nanoparticles made of thiolated quaternary chitosan crosslinked with hyaluronan.

PubMed

Zambito, Ylenia; Felice, Francesca; Fabiano, Angela; Di Stefano, Rossella; Di Colo, Giacomo

2013-01-30

Mucoadhesive polymeric nanoparticles intended for drug transport across the gastrointestinal mucosa were prepared from quaternary ammonium-chitosan conjugates synthesised from reduced-MW chitosan (32 kDa). Conjugates contained pendant moieties of 2-4 adjacent diethyl-dimethylene-ammonium groups substituted on repeating units (26-55%). Conjugates were thiolated via amide bonds with thioglycolic acid to yield products with thiol content in the 35-87 μmol/g range. Nanoparticles with mean size in the 270-370 nm range and positive zeta-potential (+3.7 to +12.5 mV) resulted from ionotropic gelation of the thiolated conjugates with de-polymerised hyaluronic acid (470 kDa). The nanoparticles were fairly stable in size and thiol content and showed a significant mucoadhesivity, matching and even exceeding that of the constituent polymers. Nanoparticles were internalised by endothelial progenitor cells in direct relation to their surface charge intensity. Nanoparticle uptake significantly improved cell viability and resistance to oxidation. The lyophilised nanoparticles were re-dispersible and could make a manageable formulation for oral use. Copyright © 2012 Elsevier Ltd. All rights reserved.

Hyperforin changes the zinc-storage capacities of brain cells.

PubMed

Gibon, Julien; Richaud, Pierre; Bouron, Alexandre

2011-12-01

In vitro and in vivo experiments were carried out to investigate the consequences on brain cells of a chronic treatment with hyperforin, a plant extract known to dissipate the mitochondrial membrane potential and to release Zn(2+) and Ca(2+) from these organelles. Dissociated cortical neurons were grown in a culture medium supplemented with 1 μM hyperforin. Live-cell imaging experiments with the fluorescent probes FluoZin-3 and Fluo-4 show that a 3 day-hyperforin treatment diminishes the size of the hyperforin-sensitive pools of Ca(2+) and Zn(2+) whereas it increases the size of the DTDP-sensitive pool of Zn(2+) without affecting the ionomycin-sensitive pool of Ca(2+). When assayed by quantitative PCR the levels of mRNA coding for metallothioneins (MTs) I, II and III were increased in cortical neurons after a 3 day-hyperforin treatment. This was prevented by the zinc chelator TPEN, indicating that the plant extract controls the expression of MTs in a zinc-dependent manner. Brains of adult mice who received a daily injection (i.p.) of hyperforin (4 mg/kg/day) for 4 weeks had a higher sulphur content than control animals. They also exhibited an enhanced expression of the genes coding for MTs. However, the long-term treatment did not affect the brain levels of calcium and zinc. Based on these results showing that hyperforin influences the size of the internal pools of Zn(2+), the expression of MTs and the brain cellular sulphur content, it is proposed that hyperforin changes the Zn-storage capacity of brain cells and interferes with their thiol status. Copyright © 2011 Elsevier Ltd. All rights reserved.

The comparison of protein-entrapped liposomes and lipoparticles: preparation, characterization, and efficacy of cellular uptake

PubMed Central

Chang, Wei-Kuo; Tai, Yu-Ju; Chiang, Chiao-Hsi; Hu, Chieh-Shen; Hong, Po-Da; Yeh, Ming-Kung

2011-01-01

Fluorescein isothiocyanate-conjugated bovine serum albumin (FITC-BSA)-loaded polyethylene glycol (PEG)-modified liposomes and lipoparticles with high protein entrapment were developed. The lipid formula of the liposomes contained PEGylated lipids and unsaturated fatty acids for enhancing membrane fluidity and effective delivery into cells. The preparation techniques, lipid content, and PEG-modified lipoparticle ratios were evaluated. The PEG-modified lipoparticles prepared by ethanol injection extrusion (100 nm pore size) achieve a population of blank liposomes with a mean size of 125 ± 2.3 nm and a zeta potential of −12.4 ± 1.5 mV. The average particle size of the PEG-modified lipoparticles was 133.7 ± 8.6 nm with a zeta potential of +13.3 mV. Lipoparticle conformation was determined using transmission electron microscopy and field-emission scanning electron microscopy. The FITC-BSA encapsulation efficiency was dramatically increased from 19.0% for liposomes to 59.7% for lipoparticles. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) results confirmed the preparation process, and an 8-hour leaching test did not harm the protein structure. Once prepared, the physical and chemical stability of the PEG-modified lipoparticle formulations was satisfactory over 90 days. In vitro retention tests indicated that the 50% retention time for the protein-containing lipoparticles was 7.9 hours, substantially longer than the liposomes at 3.3 hours. A Caco-2 cell model was used for evaluating the cytotoxicity and cell uptake efficiency of the PEG-modified lipoparticles. At a lipid content below 0.25 mM, neither the liposomes nor the lipoparticles caused significant cellular cytotoxicity (P < 0.01) and FITC-BSA was significantly taken up into cells within 60 minutes (P < 0.01). PMID:22072876

Platinum nanoparticles and their cellular uptake and DNA platination at non-cytotoxic concentrations.

PubMed

Gehrke, Helge; Pelka, Joanna; Hartinger, Christian G; Blank, Holger; Bleimund, Felix; Schneider, Reinhard; Gerthsen, Dagmar; Bräse, Stefan; Crone, Marlene; Türk, Michael; Marko, Doris

2011-07-01

Three differently sized, highly dispersed platinum nanoparticle (Pt-NP) preparations were generated by supercritical fluid reactive deposition (SFRD) and deposited on a β-cyclodextrin matrix. The average particle size and size distribution were steered by the precursor reduction conditions, resulting in particle preparations of <20, <100 and >100 nm as characterised by TEM and SEM. As reported previously, these Pt-NPs were found to cause DNA strand breaks in human colon carcinoma cells (HT29) in a concentration- and time-dependent manner and a distinct size dependency. Here, we addressed the question whether Pt-NPs might affect directly DNA integrity in these cells and thus behave analogous to platinum-based chemotherapeutics such as cisplatin. Therefore, DNA-associated Pt as well as the translocation of Pt-NPs through a Caco-2 monolayer was quantified by ICP-MS. STEM imaging demonstrated that Pt-NPs were taken up into HT29 cells in their particulate and aggregated form, but appear not to translocate into the nucleus or interact with mitochondria. The platinum content of the DNA of HT29 cells was found to increase in a time- and concentration-dependent manner with a maximal effect at 1,000 ng/cm(2). ICP-MS analysis of the cell culture medium indicated the formation of soluble Pt species, although to a limited extent. The observations suggest that DNA strand breaks mediated by metallic Pt-NPs are caused by Pt ions forming during the incubation of cells with these nanoparticles.

Antitumor activity of sorafenib-incorporated nanoparticles of dextran/poly(dl-lactide- co-glycolide) block copolymer

NASA Astrophysics Data System (ADS)

Kim, Do Hyung; Kim, Min-Dae; Choi, Cheol-Woong; Chung, Chung-Wook; Ha, Seung Hee; Kim, Cy Hyun; Shim, Yong-Ho; Jeong, Young-Il; Kang, Dae Hwan

2012-01-01

Sorafenib-incoporated nanoparticles were prepared using a block copolymer that is composed of dextran and poly( DL-lactide- co-glycolide) [Dex bLG] for antitumor drug delivery. Sorafenib-incorporated nanoparticles were prepared by a nanoprecipitation-dialysis method. Sorafenib-incorporated Dex bLG nanoparticles were uniformly distributed in an aqueous solution regardless of the content of sorafenib. Transmission electron microscopy of the sorafenib-incorporated Dex bLG nanoparticles revealed a spherical shape with a diameter < 300 nm. Sorafenib-incorporated Dex bLG nanoparticles at a polymer/drug weight ratio of 40:5 showed a relatively uniform size and morphology. Higher initial drug feeding was associated with increased drug content in nanoparticles and in nanoparticle size. A drug release study revealed a decreased drug release rate with increasing drug content. In an in vitro anti-proliferation assay using human cholangiocarcinoma cells, sorafenib-incorporated Dex bLG nanoparticles showed a similar antitumor activity as sorafenib. Sorafenib-incorporated Dex bLG nanoparticles are promising candidates as vehicles for antitumor drug targeting.

Nose-to-Brain Delivery: Investigation of the Transport of Nanoparticles with Different Surface Characteristics and Sizes in Excised Porcine Olfactory Epithelium.

PubMed

Mistry, Alpesh; Stolnik, Snjezana; Illum, Lisbeth

2015-08-03

The ability to deliver therapeutically relevant amounts of drugs directly from the nasal cavity to the central nervous system to treat neurological diseases is dependent on the availability of efficient drug delivery systems. Increased delivery and/or therapeutic effect has been shown for drugs encapsulated in nanoparticles; however, the factors governing the transport of the drugs and/or the nanoparticles from the nasal cavity to the brain are not clear. The present study evaluates the potential transport of nanoparticles across the olfactory epithelium in relation to nanoparticle characteristics. Model systems, 20, 100, and 200 nm fluorescent carboxylated polystyrene (PS) nanoparticles that were nonmodified or surface modified with polysorbate 80 (P80-PS) or chitosan (C-PS), were assessed for transport across excised porcine olfactory epithelium mounted in a vertical Franz diffusion cell. Assessment of the nanoparticle content in the donor chamber of the diffusion cell, accompanied by fluorescence microscopy of dismounted tissues, revealed a loss of nanoparticle content from the donor suspension and their association with the excised tissue, depending on the surface properties and particle size. Chitosan surface modification of PS nanoparticles resulted in the highest tissue association among the tested systems, with the associated nanoparticles primarily located in the mucus, whereas the polysorbate 80-modified nanoparticles showed some penetration into the epithelial cell layer. Assessment of the bioelectrical properties, metabolic activity, and histology of the excised olfactory epithelium showed that C-PS nanoparticles applied in pH 6.0 buffer produced a damaging effect on the epithelial cell layer in a size-dependent manner, with fine 20 nm sized nanoparticles causing substantial tissue damage relative to that with the 100 and 200 nm counterparts. Although histology showed that the olfactory tissue was affected by the application of citrate buffer that was augmented by addition of chitosan in solution, this was not reflected in the bioelectrical parameters and the metabolic activity of the tissue. Regarding transport across the excised olfactory tissue, none of the nanoparticle systems tested, irrespective of particle size or surface modification, was transported across the epithelium to appear in measurable amounts in the receiver chamber.

Simultaneous cathodoluminescence and electron microscopy cytometry of cellular vesicles labeled with fluorescent nanodiamonds

NASA Astrophysics Data System (ADS)

Nagarajan, Sounderya; Pioche-Durieu, Catherine; Tizei, Luiz H. G.; Fang, Chia-Yi; Bertrand, Jean-Rémi; Le Cam, Eric; Chang, Huan-Cheng; Treussart, François; Kociak, Mathieu

2016-06-01

Light and Transmission Electron Microscopies (LM and TEM) hold potential in bioimaging owing to the advantages of fast imaging of multiple cells with LM and ultrastructure resolution offered by TEM. Integrated or correlated LM and TEM are the current approaches to combine the advantages of both techniques. Here we propose an alternative in which the electron beam of a scanning TEM (STEM) is used to excite concomitantly the luminescence of nanoparticle labels (a process known as cathodoluminescence, CL), and image the cell ultrastructure. This CL-STEM imaging allows obtaining luminescence spectra and imaging ultrastructure simultaneously. We present a proof of principle experiment, showing the potential of this technique in image cytometry of cell vesicular components. To label the vesicles we used fluorescent diamond nanocrystals (nanodiamonds, NDs) of size ~150 nm coated with different cationic polymers, known to trigger different internalization pathways. Each polymer was associated with a type of ND with a different emission spectrum. With CL-STEM, for each individual vesicle, we were able to measure (i) their size with nanometric resolution, (ii) their content in different ND labels, and realize intracellular component cytometry. In contrast to the recently reported organelle flow cytometry technique that requires cell sonication, CL-STEM-based image cytometry preserves the cell integrity and provides a much higher resolution in size. Although this novel approach is still limited by a low throughput, the automatization of data acquisition and image analysis, combined with improved intracellular targeting, should facilitate applications in cell biology at the subcellular level.Light and Transmission Electron Microscopies (LM and TEM) hold potential in bioimaging owing to the advantages of fast imaging of multiple cells with LM and ultrastructure resolution offered by TEM. Integrated or correlated LM and TEM are the current approaches to combine the advantages of both techniques. Here we propose an alternative in which the electron beam of a scanning TEM (STEM) is used to excite concomitantly the luminescence of nanoparticle labels (a process known as cathodoluminescence, CL), and image the cell ultrastructure. This CL-STEM imaging allows obtaining luminescence spectra and imaging ultrastructure simultaneously. We present a proof of principle experiment, showing the potential of this technique in image cytometry of cell vesicular components. To label the vesicles we used fluorescent diamond nanocrystals (nanodiamonds, NDs) of size ~150 nm coated with different cationic polymers, known to trigger different internalization pathways. Each polymer was associated with a type of ND with a different emission spectrum. With CL-STEM, for each individual vesicle, we were able to measure (i) their size with nanometric resolution, (ii) their content in different ND labels, and realize intracellular component cytometry. In contrast to the recently reported organelle flow cytometry technique that requires cell sonication, CL-STEM-based image cytometry preserves the cell integrity and provides a much higher resolution in size. Although this novel approach is still limited by a low throughput, the automatization of data acquisition and image analysis, combined with improved intracellular targeting, should facilitate applications in cell biology at the subcellular level. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01908k

Solutions to an advanced functional partial differential equation of the pantograph type

PubMed Central

Zaidi, Ali A.; Van Brunt, B.; Wake, G. C.

2015-01-01

A model for cells structured by size undergoing growth and division leads to an initial boundary value problem that involves a first-order linear partial differential equation with a functional term. Here, size can be interpreted as DNA content or mass. It has been observed experimentally and shown analytically that solutions for arbitrary initial cell distributions are asymptotic as time goes to infinity to a certain solution called the steady size distribution. The full solution to the problem for arbitrary initial distributions, however, is elusive owing to the presence of the functional term and the paucity of solution techniques for such problems. In this paper, we derive a solution to the problem for arbitrary initial cell distributions. The method employed exploits the hyperbolic character of the underlying differential operator, and the advanced nature of the functional argument to reduce the problem to a sequence of simple Cauchy problems. The existence of solutions for arbitrary initial distributions is established along with uniqueness. The asymptotic relationship with the steady size distribution is established, and because the solution is known explicitly, higher-order terms in the asymptotics can be readily obtained. PMID:26345391

Solutions to an advanced functional partial differential equation of the pantograph type.

PubMed

Zaidi, Ali A; Van Brunt, B; Wake, G C

2015-07-08

A model for cells structured by size undergoing growth and division leads to an initial boundary value problem that involves a first-order linear partial differential equation with a functional term. Here, size can be interpreted as DNA content or mass. It has been observed experimentally and shown analytically that solutions for arbitrary initial cell distributions are asymptotic as time goes to infinity to a certain solution called the steady size distribution. The full solution to the problem for arbitrary initial distributions, however, is elusive owing to the presence of the functional term and the paucity of solution techniques for such problems. In this paper, we derive a solution to the problem for arbitrary initial cell distributions. The method employed exploits the hyperbolic character of the underlying differential operator, and the advanced nature of the functional argument to reduce the problem to a sequence of simple Cauchy problems. The existence of solutions for arbitrary initial distributions is established along with uniqueness. The asymptotic relationship with the steady size distribution is established, and because the solution is known explicitly, higher-order terms in the asymptotics can be readily obtained.

Micro-mechanical modelling of cellulose aerogels from molten salt hydrates.

PubMed

Rege, Ameya; Schestakow, Maria; Karadagli, Ilknur; Ratke, Lorenz; Itskov, Mikhail

2016-09-14

In this paper, a generalised micro-mechanical model capable of capturing the mechanical behaviour of polysaccharidic aerogels, in particular cellulose aerogels, is proposed. To this end, first the mechanical structure and properties of these highly nanoporous cellulose aerogels prepared from aqueous salt hydrate melts (calcium thiocyanate, Ca(SCN)2·6H2O and zinc chloride, ZnCl2·4H2O) are studied. The cellulose content within these aerogels is found to have a direct relation to the microstructural quantities such as the fibril length and diameter. This, along with porosity, appears to influence the resulting mechanical properties. Furthermore, experimental characterisation of cellulose aerogels was done using scanning electron microscopy (SEM), pore-size data analysis, and compression tests. Cellulose aerogels are of a characteristic cellular microstructures and accordingly a network formed by square shaped cells is considered in the micro-mechanical model proposed in this paper. This model is based on the non-linear bending and collapse of such cells of varying pore sizes. The extended Euler-Bernoulli beam theory for large deflections is used to describe the bending in the cell walls. The proposed model is physically motivated and demonstrates a good agreement with our experimental data of both ZnCl2 and Ca(SCN)2 based cellulose aerogels with different cellulose contents.

Methotrexate Nanoparticles Prepared with Codendrimer from Polyamidoamine (PAMAM) and Oligoethylene Glycols (OEG) Dendrons: Antitumor Efficacy in Vitro and in Vivo

NASA Astrophysics Data System (ADS)

Zhao, Yanna; Guo, Yifei; Li, Ran; Wang, Ting; Han, Meihua; Zhu, Chunyan; Wang, Xiangtao

2016-07-01

The novel methotrexate-loaded nanoparticles (MTX/PGD NPs) prepared with amphiphilic codendrimer PGD from polyamidoamine and oligothylene glycol dendrons were obtained via antisolvent precipitation method augmented by ultrasonication. Based on the excellent hydrophility of PGD, the drug-loaded nanoparticles could be investigated easily with the high drug-loading content (~85.2%, w/w). The MTX/PGD NPs possessed spherical morphology, nanoscaled particle size (approximately 182.4 nm), and narrow particle size distribution. Release of MTX from MTX/PGD NPs showed a sustained release manner and completed within 48 h. Hemolytic evaluation indicated MTX/PGD NPs presented good blood compatibility, and the cytotoxicity of nanoparticles against breast cancer cells in vitro, biodistribution in tumor tissue, and antitumor efficacy in vivo were enhanced significantly compared to MTX injection. According to the higher drug-loading content, enhanced antitumor efficacy, and appropriate particle size, MTX/PGD NPs as the drug delivery systems could have potential application for cancer chemotherapy in clinic.

Methotrexate Nanoparticles Prepared with Codendrimer from Polyamidoamine (PAMAM) and Oligoethylene Glycols (OEG) Dendrons: Antitumor Efficacy in Vitro and in Vivo

PubMed Central

Zhao, Yanna; Guo, Yifei; Li, Ran; Wang, Ting; Han, Meihua; Zhu, Chunyan; Wang, Xiangtao

2016-01-01

The novel methotrexate-loaded nanoparticles (MTX/PGD NPs) prepared with amphiphilic codendrimer PGD from polyamidoamine and oligothylene glycol dendrons were obtained via antisolvent precipitation method augmented by ultrasonication. Based on the excellent hydrophility of PGD, the drug-loaded nanoparticles could be investigated easily with the high drug-loading content (~85.2%, w/w). The MTX/PGD NPs possessed spherical morphology, nanoscaled particle size (approximately 182.4 nm), and narrow particle size distribution. Release of MTX from MTX/PGD NPs showed a sustained release manner and completed within 48 h. Hemolytic evaluation indicated MTX/PGD NPs presented good blood compatibility, and the cytotoxicity of nanoparticles against breast cancer cells in vitro, biodistribution in tumor tissue, and antitumor efficacy in vivo were enhanced significantly compared to MTX injection. According to the higher drug-loading content, enhanced antitumor efficacy, and appropriate particle size, MTX/PGD NPs as the drug delivery systems could have potential application for cancer chemotherapy in clinic. PMID:27388443

Synchronization of Mammalian Cells and Nuclei by Centrifugal Elutriation.

PubMed

Banfalvi, Gaspar

2017-01-01

Synchronized populations of large numbers of cells can be obtained by centrifugal elutriation on the basis of sedimentation properties of small round particles, with minimal perturbation of cellular functions. The physical characteristics of cell size and sedimentation velocity are operative in the technique of centrifugal elutriation also known as counterstreaming centrifugation. The elutriator is an advanced device for increasing the sedimentation rate to yield enhanced resolution of cell separation. A random population of cells is introduced into the elutriation chamber of an elutriator rotor running in a specially designed centrifuge. By increasing step-by-step the flow rate of the elutriation fluid, successive populations of relatively homogeneous cell size can be removed from the elutriation chamber and used as synchronized subpopulations. For cell synchronization by centrifugal elutriation, early log S phase cell populations are most suitable where most of the cells are in G1 and S phase (>80 %). Apoptotic cells can be found in the early elutriation fractions belonging to the sub-Go window. Protocols for the synchronization of nuclei of murine pre-B cells and high-resolution centrifugal elutriation of CHO cells are given. The verification of purity and cell cycle positions of cells in elutriated fractions includes the measurement of DNA synthesis by [ 3 H]-thymidine incorporation and DNA content by propidium iodide flow cytometry.

High Resolution Characterization of Engineered Nanomaterial Dispersions in Complex Media Using Tunable Resistive Pulse Sensing Technology

PubMed Central

2015-01-01

In vitro toxicity assessment of engineered nanomaterials (ENM), the most common testing platform for ENM, requires prior ENM dispersion, stabilization, and characterization in cell culture media. Dispersion inefficiencies and active aggregation of particles often result in polydisperse and multimodal particle size distributions. Accurate characterization of important properties of such polydisperse distributions (size distribution, effective density, charge, mobility, aggregation kinetics, etc.) is critical for understanding differences in the effective dose delivered to cells as a function of time and dispersion conditions, as well as for nano–bio interactions. Here we have investigated the utility of tunable nanopore resistive pulse sensing (TRPS) technology for characterization of four industry relevant ENMs (oxidized single-walled carbon nanohorns, carbon black, cerium oxide and nickel nanoparticles) in cell culture media containing serum. Harvard dispersion and dosimetry platform was used for preparing ENM dispersions and estimating delivered dose to cells based on dispersion characterization input from dynamic light scattering (DLS) and TRPS. The slopes of cell death vs administered and delivered ENM dose were then derived and compared. We investigated the impact of serum protein content, ENM concentration, and cell medium on the size distributions. The TRPS technology offers higher resolution and sensitivity compared to DLS and unique insights into ENM size distribution and concentration, as well as particle behavior and morphology in complex media. The in vitro dose–response slopes changed significantly for certain nanomaterials when delivered dose to cells was taken into consideration, highlighting the importance of accurate dispersion and dosimetry in in vitro nanotoxicology. PMID:25093451

Detection of early changes in lung cell cytology by flow-systems analysis techniques. [Rats

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

Steinkamp, J.A.; Wilson, J.S.; Svitra, Z.V.

1980-03-01

Ongoing experiments designed to develop automated flow-analysis methods for assaying damage to pulmonary lavage cells in experimental animals exposed by inhalation to environmental pollutants are summarized. Pulmonary macrophages were characterized on their ability to phagocytize polystyrene latex fluorescent spheres. Lung cells consisting primarily of macrophages and leukocytes were analyzed for fluorescence (phagocytosis of spheres) and size using flow cytometric methods. Studies also concentrated on combining phagocytosis with other cellular parameters (DNA content, cell viability, and B-glucuronidase activity). As baseline studies are completed in normal animals, experimental animals will be exposed to gaseous and particulate environmental pollutants. (ERB

Morphokinetic Reaction of Cells of Streptococcus faecalis (ATCC 9790) to Specific Inhibition of Macromolecular Synthesis: Dependence of Mesosome Growth on Deoxyribonucleic Acid Synthesis

PubMed Central

Higgins, Michael L.; Daneo-Moore, Lolita

1972-01-01

The application of quantitative electron microscopy to thin sections of cells of Streptococcus faecalis specifically inhibited for deoxyribonucleic acid (DNA), ribonucleic acid, and protein synthesis shows that septal mesosomes (i) increase in size when protein synthesis is inhibited by at least 80% while DNA synthesis proceeds at no less than 50% of the control rate and (ii) decrease in size when DNA synthesis is inhibited 50% or more during the initial 10 min of treatment. This indicates that fluctuations in mesosome size are dependent on the extent of DNA synthesis. The fluctuations in mesosome areas observed on treatment do not correlate with the kinetics of glycerol incorporation per milliliter of a culture. However, when glycerol incorporation is placed on a per cell basis, a strong correlation is observed between increases in (i) the thickness of the electron-transparent layer of the cytoplasmic membrane and (ii) the amount of glycerol incorporated per cell. It seems that the electron-transparent membrane layer may thicken to accommodate changes in lipid content when protein and lipid synthesis are uncoupled. Images PMID:4110926

Changes in compartments of hemospoietic and stromal marrow progenitor cells after continuous low dose gamma-irradiation

NASA Astrophysics Data System (ADS)

Domaratskaya, E.; Starostin, V.

The low dose continuous gamma-irradiation chosen corresponded with that affected the organisms onboard a spacecraft (Mitrikas, Tsetlin, 2000). F1 (CBAxC57Bl/6) male and female mice were used at 3 4 months of age. Experimental mice were- irradiated during 10 days to a total dose of 15 mGy (Co60 gamma-sources, mean dose rate of 1.5-2.0 mGy/day). Another group of intact mice served as control. Younger and advanced hemopoietic progenitors measured at day 11 (i.e. CFU -S-11) and day 7 (i.e. CFU-S-7), respectively, after transplantation of test donor cells were assayed by the method of Till and McCulloch (1961). Stromal changes were evaluated by estimation of in vitro fibroblastic colony-forming units (CFU -F ) content and by the ability of ectopically grafted (under renal capsule) stroma to regenerate the new bone marrow organ. CFU-S-11 number increased of 40% as compared with control and almost 2-fold higher than that of CFU-S-7. The CFU-F content increased almost of 3-fold. Size of ectopic marrow transplants was estimated at day 70 following grafting by counting myelokariocyte and CFU -S number that repopulated the newly formed bone marrow organ. It was found more than 2-fold increase of myelokariocytes in transplants produced by marrow stroma of irradiated donors. CFU -S contents in transplants increased strikingly in comparison to control level. CFU-S-7 and CFU-S-11 increased of 7.5- and of 3.7-fold, respectively, i.e. the rate of advanced CFU - S predominated. It should be noted a good correlation between number of stromal progenitor cells (CFU-F) and ectopic transplant sizes evaluated as myelokaryocyte counts when irradiated donors used. In the same time, if sizes of transplants was measured as CFU-S-7 and CFU - S-11 numbers, their increases were more pronounced. Therefore, continuous low dose gamma- irradiation augments significantly both hemopoietic and stromal progenitor cell number in bone marrow. Additionally, the ratio of distinct CFU -S subpopulations changes. Stromal cells acquire the ability to form much greater hemopoietic territories and seems to create the microenvironments of another quality with stimulatory effects on CFU - S proliferation.

Intracellular ice formation in insects: unresolved after 50 years?

PubMed

Sinclair, Brent J; Renault, David

2010-01-01

Many insects survive internal ice formation. The general model of freeze tolerance is of extracellular ice formation (EIF) whereby ice formation in the haemocoel leads to osmotic dehydration of the cells, whose contents remain unfrozen. However, survivable intracellular ice formation (IIF) has been reported in fat body and certain other cells of some insects. Although the cellular location of ice has been determined only in vitro, several lines of evidence suggest that IIF occurs in vivo. Both cell-to-cell propagation of intracellular ice and inoculation from the haemocoel may be important, although the route of ice into the cell is unclear. It is unclear why some cells survive IIF and others do not, but it is suggested that the shape, size, and low water content of fat body cells may predispose them towards surviving ice formation. We speculate that IIF may reduce water loss in some freeze tolerant species, but there are too few data to build a strong conceptual model of the advantages of IIF. We suggest that new developments in microscopy and other forms of imaging may allow investigation of the cellular location of ice in freeze tolerant insects in vivo.

Nuclear protein accumulation in cellular senescence and organismal aging revealed with a novel single-cell resolution fluorescence microscopy assay.

PubMed

De Cecco, Marco; Jeyapalan, Jessie; Zhao, Xiaoai; Tamamori-Adachi, Mimi; Sedivy, John M

2011-10-01

Replicative cellular senescence was discovered some 50 years ago. The phenotypes of senescent cells have been investigated extensively in cell culture, and found to affect essentially all aspects of cellular physiology. The relevance of cellular senescence in the context of age-associated pathologies as well as normal aging is a topic of active and ongoing interest. Considerable effort has been devoted to biomarker discovery to enable the microscopic detection of single senescent cells in tissues. One characteristic of senescent cells documented very early in cell culture studies was an increase in cell size and total protein content, but whether this occurs in vivo is not known. A limiting factor for studies of protein content and localization has been the lack of suitable fluorescence microscopy tools. We have developed an easy and flexible method, based on the merocyanine dye known as NanoOrange, to visualize and quantitatively measure total protein levels by high resolution fluorescence microscopy. NanoOrange staining can be combined with antibody-based immunofluorescence, thus providing both specific target and total protein information in the same specimen. These methods are optimally combined with automated image analysis platforms for high throughput analysis. We document here increasing protein content and density in nuclei of senescent human and mouse fibroblasts in vitro, and in liver nuclei of aged mice in vivo. Additionally, in aged liver nuclei NanoOrange revealed protein-dense foci that colocalize with centromeric heterochromatin.

Nuclear protein accumulation in cellular senescence and organismal aging revealed with a novel single-cell resolution fluorescence microscopy assay

PubMed Central

De Cecco, Marco; Jeyapalan, Jessie; Zhao, Xiaoai; Tamamori-Adachi, Mimi; Sedivy, John M.

2011-01-01

Replicative cellular senescence was discovered some 50 years ago. The phenotypes of senescent cells have been investigated extensively in cell culture, and found to affect essentially all aspects of cellular physiology. The relevance of cellular senescence in the context of age-associated pathologies as well as normal aging is a topic of active and ongoing interest. Considerable effort has been devoted to biomarker discovery to enable the microscopic detection of single senescent cells in tissues. One characteristic of senescent cells documented very early in cell culture studies was an increase in cell size and total protein content, but whether this occurs in vivo is not known. A limiting factor for studies of protein content and localization has been the lack of suitable fluorescence microscopy tools. We have developed an easy and flexible method, based on the merocyanine dye known as NanoOrange, to visualize and quantitatively measure total protein levels by high resolution fluorescence microscopy. NanoOrange staining can be combined with antibody-based immunofluorescence, thus providing both specific target and total protein information in the same specimen. These methods are optimally combined with automated image analysis platforms for high throughput analysis. We document here increasing protein content and density in nuclei of senescent human and mouse fibroblasts in vitro, and in liver nuclei of aged mice in vivo. Additionally, in aged liver nuclei NanoOrange revealed protein-dense foci that colocalize with centromeric heterochromatin. PMID:22006542

Cupriavidus taiwanensis Bacteroids in Mimosa pudica Indeterminate Nodules Are Not Terminally Differentiated ▿

PubMed Central

Marchetti, Marta; Catrice, Olivier; Batut, Jacques; Masson-Boivin, Catherine

2011-01-01

The beta-rhizobium Cupriavidus taiwanensis forms indeterminate nodules on Mimosa pudica. C. taiwanensis bacteroids resemble free-living bacteria in terms of genomic DNA content, cell size, membrane permeability, and viability, in contrast to bacteroids in indeterminate nodules of the galegoid clade. Bacteroid differentiation is thus unrelated to nodule ontogeny. PMID:21257807

Raman and coherent anti-Stokes Raman scattering microscopy studies of changes in lipid content and composition in hormone-treated breast and prostate cancer cells

NASA Astrophysics Data System (ADS)

Potcoava, Mariana C.; Futia, Gregory L.; Aughenbaugh, Jessica; Schlaepfer, Isabel R.; Gibson, Emily A.

2014-11-01

Increasing interest in the role of lipids in cancer cell proliferation and resistance to drug therapies has motivated the need to develop better tools for cellular lipid analysis. Quantification of lipids in cells is typically done by destructive chromatography protocols that do not provide spatial information on lipid distribution and prevent dynamic live cell studies. Methods that allow the analysis of lipid content in live cells are therefore of great importance. Using micro-Raman spectroscopy and coherent anti-Stokes Raman scattering (CARS) microscopy, we generated a lipid profile for breast (T47D, MDA-MB-231) and prostate (LNCaP, PC3) cancer cells upon exposure to medroxyprogesterone acetate (MPA) and synthetic androgen R1881. Combining Raman spectra with CARS imaging, we can study the process of hormone-mediated lipogenesis. Our results show that hormone-treated cancer cells T47D and LNCaP have an increased number and size of intracellular lipid droplets and higher degree of saturation than untreated cells. MDA-MB-231 and PC3 cancer cells showed no significant changes upon treatment. Principal component analysis with linear discriminant analysis of the Raman spectra was able to differentiate between cancer cells that were treated with MPA, R1881, and untreated.

Thermal, Morphological and Rheological Properties of Rigid Polyurethane Foams as Thermal Insulating Materials

NASA Astrophysics Data System (ADS)

Kim, Ji Mun; Han, Mi Sun; Kim, Youn Hee; Kim, Woo Nyon

2008-07-01

The polyurethane foams (PUFs) were prepared by polyether polyols, polymeric 4,4'-diphenylmethane diisocyanate (PMDI), silicone surfactants, amine catalysts and cyclopentane as a blowing agent. Solid and liquid type fillers were used as a nucleating agent to decrease a cell size of the PUFs as well as improve the thermal insulating properties of the PUFs. The PUFs were prepared by adding solid and liquid type fillers in the range of 1 to 3 wt%. For the liquid type fillers, the cell size of the PUFs showed minimum and found to decrease compared the PUF without adding fillers. Also, thermal conductivity of the PUFs with adding fillers showed minimum. For the solid type fillers, cell size and thermal conductivity of the PUFs were observed to decrease with the filler content up to 3 wt%. From these results, it is suggested that the thermal insulating property of the PUFs can be improved by adding fillers as a nucleating agent. Also, storage and loss modulus of the PUFs will be presented to study gelling points of the PUFs.

Fabrication of porous chitosan/poly(vinyl alcohol) reinforced single-walled carbon nanotube nanocomposites for neural tissue engineering.

PubMed

Shokrgozar, Mohammad Ali; Mottaghitalab, Fatemeh; Mottaghitalab, Vahid; Farokhi, Mehdi

2011-04-01

With the ability to form a nano-sized fibrous structure with large pore sizes mimicking the extracellular matrix (ECM), electrospinning was used to fabricate chitosan/poly(vinyl alcohol) nanofibers reinforced by single-walled carbon nanotube (SWNT-CS/PVA) for potential use in neural tissue engineering. Moreover, ultrasonication was performed to fabricate highly dispersed SWNT/CS solution with 7%, 12%, and 17% SWNT content prior to electrospinning process. In the present study, a number of properties of CS/PVA reinforced SWNTs nanocomposites were evaluated. The in vitro biocompatibility of the electrospun fiber mats was also assessed using human brain-derived cells and U373 cell lines. The results have shown that SWNTs as reinforcing phase can augment the morphology, porosity, and structural properties of CS/PVA nanofiber composites and thus benefit the proliferation rate of both cell types. In addition, the cells exhibit their normal morphology while integrating with surrounding fibers. The results confirmed the potential of SWNT-CS/PVA nanocomposites as scaffold for neural tissue engineering.

Mechanical properties of palm oil based bio-polyurethane foam of free rise and various densities

NASA Astrophysics Data System (ADS)

Hilmi, Hazmi; Zainuddin, Firuz; Cheng, Teoh Siew; Lan, Du Ngoc Uy

2017-12-01

Bio-foam was produced from palm oil-based polyol (POBP) and methylene diphenyl diisocyanate (MDI) with weight ratio of 1:1. The effect of opened mould (as free rise) and closed mould (control expansion) was investigated. Different densities of bio-polyurethane foam (0.3, 0.4 and 0.5 g.cm-3) were prepared using the closed mould system. The effect of density on morphology and compressive properties of bio-foam was studied. Results showed that bio-foam prepared by closed mould method possessed homogeneous cell structure and cell size compared to bio-foam prepared by opened mould. In addition, bio-foam using closed mould system had higher compression strength (0.47 MPa) than that of bio-foam using opened mould system (0.13 MPa). With higher density and lesser porosity, the compressive modulus and compressive strength of bio foams will be higher. The increase in compressive properties is due to the decrease in the cells size, more homogeneous cell structure and reduction in porosity content.

Functional heterogeneity and heritability in CHO cell populations.

PubMed

Davies, Sarah L; Lovelady, Clare S; Grainger, Rhian K; Racher, Andrew J; Young, Robert J; James, David C

2013-01-01

In this study, we address the hypothesis that it is possible to exploit genetic/functional variation in parental Chinese hamster ovary (CHO) cell populations to isolate clonal derivatives that exhibit superior, heritable attributes for biomanufacturing--new parental cell lines which are inherently more "fit for purpose." One-hundred and ninety-nine CHOK1SV clones were isolated from a donor CHOK1SV parental population by limiting dilution cloning and microplate image analysis, followed by primary analysis of variation in cell-specific proliferation rate during extended deep-well microplate suspension culture of individual clones to accelerate genetic drift in isolated cultures. A subset of 100 clones were comparatively evaluated for transient production of a recombinant monoclonal antibody (Mab) and green fluorescent protein following transfection of a plasmid vector encoding both genes. The heritability of both cell-specific proliferation rate and Mab production was further assessed using a subset of 23 clones varying in functional capability that were subjected to cell culture regimes involving both cryopreservation and extended sub-culture. These data showed that whilst differences in transient Mab production capability were not heritable per se, clones exhibiting heritable variation in specific proliferation rate, endocytotic transfectability and N-glycan processing were identified. Finally, for clonal populations most "evolved" by extended sub-culture in vitro we investigated the relationship between cellular protein biomass content, specific proliferation rate and cell surface N-glycosylation. Rapid-specific proliferation rate was inversely correlated to CHO cell size and protein content, and positively correlated to cell surface glycan content, although substantial clone-specific variation in ability to accumulate cell biomass was evident. Taken together, our data reveal the dynamic nature of the CHO cell functional genome and the potential to evolve and isolate CHO cell variants with improved functional properties in vitro. Copyright © 2012 Wiley Periodicals, Inc.

Unusually large oilbodies are highly correlated with lower oil content in Brassica napus.

PubMed

Hu, Zhiyong; Wang, Xinfa; Zhan, Gaomiao; Liu, Guihua; Hua, Wei; Wang, Hanzhong

2009-04-01

Rapeseed cultivars exhibit a wide range of oil content in the mature seeds. Little is known about the relationship between the oilbody structures and the differences in oil contents of Brassica napus cultivars. In the present study, the oilbody morphology and its fate during the embryo development and seedling growth in several cultivars with oil contents ranging from 33.4 to 49.8% were studied. Cultivars with low oil contents (LO), some of the oilbodies were in similar size to those in cultivars with high oil content (HO), while some oilbodies in the LO cultivars were several times bigger (over 5.0 microm). These are much larger than the average size of B. napus seed oilbodies that were previously reported (Mantese et al. Ann Bot 97:999-1010, 2006). The oleosin protein levels and oleosin1 gene transcript abundances in the HO cultivars were clearly higher than in the LO cultivars. The shapes of oilbodies were similar during early stages of embryo development in both HO and LO cultivars, while as the embryos matured, the unusually large oilbodies were generated in the LO cells. After germination, the oilbodies in LO cultivars were consumed more slowly than in HO, and the seed germination rates of LO cultivars were less than those of HO cultivars. The low accumulation of oleosins results in the forming of unusually large oilbodies in LO cultivars.

Curcumin loaded pH-sensitive nanoparticles for the treatment of colon cancer.

PubMed

Prajakta, Dandekar; Ratnesh, Jain; Chandan, Kumar; Suresh, Subramanian; Grace, Samuel; Meera, Venkatesh; Vandana, Patravale

2009-10-01

The investigation was aimed at designing pH-sensitive, polymeric nanoparticles of curcumin, a natural anti-cancer agent, for the treatment of colon cancer. The objective was to enhance the bioavailability of curcumin, simultaneously reducing the required dose through selective targeting to colon. Eudragit S100 was chosen to aid targeting since the polymer dissolves at colonic pH to result in selective colonic release of the entrapped drug. Solvent emulsion-evaporation technique was employed to formulate the nanoparticles. Various process parameters were optimized and the optimized formulation was evaluated for particle size distribution and encapsulation efficiency before subjecting to freeze-drying. The freeze dried product was characterized for particle size, drug content, DSC studies, particle morphology. Anti-cancer potential of the formulation was demonstrated by MTT assay in HT-29 cell line. Nanometric, homogeneous, spherical particles were obtained with encapsulation efficiency of 72%. Freeze-dried nanoparticles exhibited a negative surface charge, drug content of > 99% and presence of drug in amorphous form which may result in possible enhanced absorption. MTT assay demonstrated almost double inhibition of the cancerous cells by nanoparticles, as compared to curcumin alone, at the concentrations tested. Enhanced action may be attributed to size influenced improved cellular uptake, and may result in reduction of overall dose requirement. Results indicate the potential for in vivo studies to establish the clinical application of the formulation.

Influence of Pb and La contents on the lattice configuration of La-substituted Pb(Zr,Ti)O3 films fabricated by CSD method.

PubMed

Shima, Hiromi; Nishida, Ken; Funakubo, Hiroshi; Iijima, Takashi; Katoda, Takashi; Naganuma, Hiroshi; Okamura, Soichiro

2009-04-01

The influence of Pb and La contents on the lattice configuration in La-substituted Pb(Zr0(.65),Ti0(.35))O3 (La- PZT) films was systematically investigated. La-PZT films with various La and Pb contents were fabricated on Pt/Ti/SiO(2)/Si substrates by chemical solution deposition (CSD). In the La- PZT films with a Pb content ratio of 125% relative to a stoichiometric value, La ions were substituted for not only A-site ions but also B-site ions at La contents greater than 3 mol%. La substitution for B-site seems to cause larger reduction of the unit cell size. In addition, we found that in the La-PZT films with a La content of 3 mol%, the Pb content of 116 mol% (120% relative to a stoichiometric value) was optimum from the viewpoint of site occupancy. This indicates that excess Pb prevented the A-site substitution of La ions.

Effects of Emulsifier, Overrun and Dasher Speed on Ice Cream Microstructure and Melting Properties.

PubMed

Warren, Maya M; Hartel, Richard W

2018-03-01

Ice cream is a multiphase frozen food containing ice crystals, air cells, fat globules, and partially coalesced fat globule clusters dispersed in an unfrozen serum phase (sugars, proteins, and stabilizers). This microstructure is responsible for ice cream's melting characteristics. By varying both formulation (emulsifier content and overrun) and processing conditions (dasher speed), the effects of different microstructural elements, particularly air cells and fat globule clusters, on ice cream melt-down properties were studied. Factors that caused an increase in shear stress within the freezer, namely increasing dasher speed and overrun, caused a decrease in air cell size and an increase in extent of fat destabilization. Increasing emulsifier content, especially of polysorbate 80, caused an increase in extent of fat destabilization. Both overrun and fat destabilization influenced drip-through rates. Ice creams with a combination of low overrun and low fat destabilization had the highest drip-through rates. Further, the amount of remnant foam left on the screen increased with reduced drip-through rates. These results provide a better understanding of the effects of microstructure components and their interactions on drip-through rate. Manipulating operating and formulation parameters in ice cream manufacture influences the microstructure (air cells, ice crystals, and fat globule clusters). This work provides guidance on which parameters have most effect on air cell size and fat globule cluster formation. Further, the structural characteristics that reduce melt-down rate were determined. Ice cream manufacturers will use these results to tailor their products for the desired quality attributes. © 2018 Institute of Food Technologists®.

The anti-inflammatory drug carprofen improves long-term outcome and induces gliogenesis after traumatic brain injury.

PubMed

Thau-Zuchman, Orli; Shohami, Esther; Alexandrovich, Alexander G; Trembovler, Victoria; Leker, Ronen R

2012-01-20

Traumatic brain injury (TBI) initiates acute and chronic inflammatory processes involving cyclooxygenase-2 (COX-2), which may have detrimental effects on outcome and especially on brain regeneration. Therefore we aimed to study whether carprofen, a COX-2 inhibitor, would improve outcome and increase neurogenesis after TBI. TBI was induced in Sabra mice that were then treated with vehicle or carprofen for 7 days. Functional outcome was evaluated with the Neurological Severity Score (NSS).Cytokine levels were assessed 4 h post-TBI and water content was measured 24 h post TBI. Mice were given BrdU to label newborn cells for 10 days. The animals were killed 90 days post-TBI and the lesion size as well as newborn cell fate were assessed. Carprofen significantly reduced lesion size (p=0.002), decreased water content in the lesioned cortex (p=0.03), reduced the number of microglia in the lesioned cortex (p<0.0001), and lowered the levels of proinflammatory cytokines (IL-1β, p=0.03; IL-6, p=0.02). Carprofen led to significantly larger improvements in functional outcome (p≤0.008) which were durable over 90 days. Carprofen also induced a threefold increase in the proliferation of new cells in the peri-lesion area (p≤0.002), but newborn cells differentiated mainly into glia in both groups. Carprofen is neuroprotective and induces cell proliferation and gliogenesis after TBI. Treatment with carprofen is consistently associated with better functional outcome. Our results imply that anti-inflammatory drugs may represent novel therapeutic options for TBI.

Contrasting growth phenology of native and invasive forest shrubs mediated by genome size.

PubMed

Fridley, Jason D; Craddock, Alaä

2015-08-01

Examination of the significance of genome size to plant invasions has been largely restricted to its association with growth rate. We investigated the novel hypothesis that genome size is related to forest invasions through its association with growth phenology, as a result of the ability of large-genome species to grow more effectively through cell expansion at cool temperatures. We monitored the spring leaf phenology of 54 species of eastern USA deciduous forests, including native and invasive shrubs of six common genera. We used new measurements of genome size to evaluate its association with spring budbreak, cell size, summer leaf production rate, and photosynthetic capacity. In a phylogenetic hierarchical model that differentiated native and invasive species as a function of summer growth rate and spring budbreak timing, species with smaller genomes exhibited both faster growth and delayed budbreak compared with those with larger nuclear DNA content. Growth rate, but not budbreak timing, was associated with whether a species was native or invasive. Our results support genome size as a broad indicator of the growth behavior of woody species. Surprisingly, invaders of deciduous forests show the same small-genome tendencies of invaders of more open habitats, supporting genome size as a robust indicator of invasiveness. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

No tillage effect on water retention characteristics of soil aggregates in rainfed semiarid conditions.

NASA Astrophysics Data System (ADS)

Blanco-Moure, Nuria; López, M. Victoria; Moret, David

2010-05-01

The evaluation of changes in soil moisture retention characteristics associated to alterations in soil structure is of great interest in tillage studies. Most of these studies have evaluated soil properties in samples of total soil but not in individual aggregates. However, soil behavior at a macroscale level depends on the aggregate properties. A better knowledge of aggregate characteristics, as the water retention properties, will help to explain, for example, the response of soil to tillage, compaction and crop growth, and hence, to plan adequate soil management practices. In this study we determine the water retention curve of soil aggregates of different sizes from a soil under two tillage systems (conventional and no tillage). The study was carried out in a silty clay loam soil of semiarid Aragon (NE Spain). Two tillage systems were compared: no tillage (NT) and conventional tillage with mouldboard plough (CT). Water retention curves (WRC) were determined for soil surface aggregates (0-5 cm) of three different sizes (8-4, 4-2 and 2-1 mm in diameter) by using the TDR-pressure cell (Moret et al. 2008. Soil Till. Res, 100, 114-119). The TDR-pressure cell is a non-destructive method which permits determining WRC with the only one and same soil sample. Thus, the pressure cell was filled with aggregates up to 4 cm height, weighted and wetted to saturation from the bottom. Pressure steps were sequentially applied at -0.5, -1.5, -3, -5, -10, -33, -100, -300 kPa, and water content of each aggregate sample was measured gravimetrically and by TDR 24 h after starting each pressure head step. The volume of the sample within the cell was also determined at this moment in order to obtain the bulk density and thus calculate the volumetric water content. A good relationship was obtained between the volumetric water content calculated from the gravimetric water content and the corresponding values measured by TDR (r2=0.907; p≤0.05). Within the same tillage treatment, no significant differences in WRC were found among soil aggregate sizes. Soil aggregates under CT retained more water at lower pressure heads in all aggregate sizes; in contrast the retention was more effective in those from NT at high pressure level. The extensive structural degradation of the CT aggregates observed during wetting with the consequent decrease in the soil volume within the transparent cell, can help to explain the different behaviour of both soils. The CT aggregates were probably disintegrated by slaking, causing a reduction in water drainage and, therefore, an increase in soil water content at low pressure heads. This idea was also confirmed with the application of the double exponential function proposed by Dexter et al. (2008. Geoderma 173, 243-253). The WRC curves measured by TDR were successfully fitted to the theoretical model proposed by Dexter (r2=0.986; p≤0.05). Thus, the model estimated that the large porosity between aggregates retain slightly more water under CT (0.36-0.39 m3 m-3) than under NT (0.31-0.35 m3 m-3). On the contrary, pores inside the aggregates tend to storage more water in NT (0.16-0.20 m3 m-3vs. 0.13-0.17 m3 m-3 in CT). These results show the suitability of NT to reduce the risk of soil crusting and compaction in agricultural lands of Aragón.

Impact of zinc supplementation on the improvement of ethanol tolerance and yield of self-flocculating yeast in continuous ethanol fermentation.

PubMed

Zhao, X Q; Xue, C; Ge, X M; Yuan, W J; Wang, J Y; Bai, F W

2009-01-01

The effects of zinc supplementation were investigated in the continuous ethanol fermentation using self-flocculating yeast. Zinc sulfate was added at the concentrations of 0.01, 0.05 and 0.1 g l(-1), respectively. Reduced average floc sizes were observed in all the zinc-supplemented cultures. Both the ethanol tolerance and thermal tolerance were significantly improved by zinc supplements, which correlated well with the increased ergosterol and trehalose contents in the yeast flocs. The highest ethanol concentration by 0.05 g l(-1) zinc sulfate supplementation attained 114.5 g l(-1), in contrast to 104.1 g l(-1) in the control culture. Glycerol production was decreased by zinc supplementations, with the lowest level 3.21 g l(-1), about 58% of the control. Zinc content in yeast cells was about 1.4 microMol g(-1) dry cell weight, about sixfold higher than that of control in all the zinc-supplemented cultures, and close correlation of zinc content in yeast cells with the cell viability against ethanol and heat shock treatment was observed. These studies suggest that exogenous zinc addition led to a reprogramming of cellular metabolic network, resulting in enhanced ethanol tolerance and ethanol production.

"Ant" and "grasshopper" life-history strategies in Saccharomyces cerevisiae.

PubMed

Spor, Aymé; Wang, Shaoxiao; Dillmann, Christine; de Vienne, Dominique; Sicard, Delphine

2008-02-13

From the evolutionary and ecological points of view, it is essential to distinguish between the genetic and environmental components of the variability of life-history traits and of their trade-offs. Among the factors affecting this variability, the resource uptake rate deserves particular attention, because it depends on both the environment and the genetic background of the individuals. In order to unravel the bases of the life-history strategies in yeast, we grew a collection of twelve strains of Saccharomyces cerevisiae from different industrial and geographical origins in three culture media differing for their glucose content. Using a population dynamics model to fit the change of population size over time, we estimated the intrinsic growth rate (r), the carrying capacity (K), the mean cell size and the glucose consumption rate per cell. The life-history traits, as well as the glucose consumption rate, displayed large genetic and plastic variability and genetic-by-environment interactions. Within each medium, growth rate and carrying capacity were not correlated, but a marked trade-off between these traits was observed over the media, with high K and low r in the glucose rich medium and low K and high r in the other media. The cell size was tightly negatively correlated to carrying capacity in all conditions. The resource consumption rate appeared to be a clear-cut determinant of both the carrying capacity and the cell size in all media, since it accounted for 37% to 84% of the variation of those traits. In a given medium, the strains that consume glucose at high rate have large cell size and low carrying capacity, while the strains that consume glucose at low rate have small cell size but high carrying capacity. These two contrasted behaviors may be metaphorically defined as "ant" and "grasshopper" strategies of resource utilization. Interestingly, a strain may be "ant" in one medium and "grasshopper" in another. These life-history strategies are discussed with regards to yeast physiology, and in an evolutionary perspective.

Regulation of cell proliferation and estrogen synthesis by ovine LH, IGF-I, and EGF in theca interstitial cells of the domestic hen cultured in defined media.

PubMed

Onagbesan, O M; Peddie, M J; Williams, J

1994-05-01

There is relatively little information on the factors which regulate the proliferation and alterations in the steroidogenic capacity of avian theca cells during follicular maturation. The development of culture conditions for these cells to determine the effects of gonadotrophin (LH) and the growth factors epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) on DNA synthesis and estrogen production is reported. Cultures were established in serum-supplemented (with fetal calf serum or chicken serum) or ITS+ (insulin, transferrin, and selenium plus additives) supplemented serum-free media. Cell replication occurred throughout the 72-hr culture period as indicated by a linear increase in the DNA content of the culture dishes. Aromatase activity of the cells as defined by conversion of androstenedione to estrogen was best maintained in serum-free medium while sera inhibited this activity. Ovine LH enhanced the aromatase activity of cultured cells from medium and small-sized follicles, while IGF-I and EGF inhibited both basal and LH-stimulated aromatase activity. LH, IGF-I, and EGF all stimulated cell proliferation as reflected by increased DNA. The responses of cells to these peptides varied with the size of the follicle, with the greatest effects on cells from F4/5.

Muscle fibre capillarization is a critical factor in muscle fibre hypertrophy during resistance exercise training in older men.

PubMed

Snijders, Tim; Nederveen, Joshua P; Joanisse, Sophie; Leenders, Marika; Verdijk, Lex B; van Loon, Luc J C; Parise, Gianni

2017-04-01

Adequate muscle fibre perfusion is critical for the maintenance of muscle mass; it is essential in the rapid delivery of oxygen, nutrients and growth factors to the muscle, stimulating muscle fibre growth. Muscle fibre capillarization is known to decrease substantially with advancing age. However, whether (relative) low muscle fibre capillarization negatively impacts the muscle hypertrophic response following resistance exercise training in older adults is unknown. Twenty-two healthy older men (71 ± 1 years) performed 24 weeks of progressive resistance type exercise training. To assess the change in muscle fibre characteristics, percutaneous biopsies from the vastus lateralis muscle were taken before and following 12 and 24 weeks of the intervention programme. A comparison was made between participants who had a relatively low type II muscle fibre capillary-to-fibre perimeter exchange index (CFPE; LOW group) and high type II muscle fibre CFPE (HIGH group) at baseline. Type I and type II muscle fibre size, satellite cell, capillary content and distance between satellite cells to the nearest capillary were determined by immunohistochemistry. Overall, type II muscle fibre size (from 5150 ± 234 to 6719 ± 446 µm 2 , P < 0.05) and satellite cell content (from 0.058 ± 0.006 to 0.090 ± 0.010 satellite cells per muscle fibre, P < 0.05) had increased significantly in response to 24 weeks of resistance exercise training. However, these improvements where mainly driven by differences in baseline type II muscle fibre capillarization, whereas muscle fibre size (from 5170 ± 390 to 7133 ± 314 µm 2 , P < 0.05) and satellite cell content (from 0.059 ± 0.009 to 0.102 ± 0.017 satellite cells per muscle fibre, P < 0.05) increased significantly in the HIGH group, no significant changes were observed in LOW group following exercise training. No significant changes in type I and type II muscle fibre capillarization were observed in response to 12 and 24 weeks of resistance exercise training in both the LOW and HIGH group. Type II muscle fibre capillarization at baseline may be a critical factor for allowing muscle fibre hypertrophy to occur during prolonged resistance exercise training in older men. © 2016 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

Sensitivity of bacteria to diamond nanoparticles of various size differs in gram-positive and gram-negative cells.

PubMed

Beranová, Jana; Seydlová, Gabriela; Kozak, Halyna; Benada, Oldřich; Fišer, Radovan; Artemenko, Anna; Konopásek, Ivo; Kromka, Alexander

2014-02-01

In this study, the influence of the size and surface termination of diamond nanoparticles (DNPs) on their antibacterial activity against Escherichia coli and Bacillus subtilis was assessed. The average size and distribution of DNPs were determined by dynamic light scattering and X-ray diffraction techniques. The chemical composition of the DNPs studied by X-ray photoelectron spectroscopy showed that DNPs > 5 nm and oxidized particles have a higher oxygen content. The antibacterial potential of DNPs was assessed by the viable count method. In general, E. coli exhibited a higher sensitivity to DNPs than B. subtilis. However, in the presence of all the DNPs tested, the B. subtilis colonies exhibited altered size and morphology. Antibacterial activity was influenced not only by DNP concentration but also by DNP size and form. Whereas untreated 5-nm DNPs were the most effective against E. coli, the antibacterial activity of 18-50-nm DNPs was higher against B. subtilis. Transmission electron microscopy showed that DNPs interact with the bacterial surface, probably affecting vital cell functions. We propose that DNPs interfere with the permeability of the bacterial cell wall and/or membrane and hinder B. subtilis colony spreading. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

DNA content analysis allows discrimination between Trypanosoma cruzi and Trypanosoma rangeli.

PubMed

Naves, Lucila Langoni; da Silva, Marcos Vinícius; Fajardo, Emanuella Francisco; da Silva, Raíssa Bernardes; De Vito, Fernanda Bernadelli; Rodrigues, Virmondes; Lages-Silva, Eliane; Ramírez, Luis Eduardo; Pedrosa, André Luiz

2017-01-01

Trypanosoma cruzi, a human protozoan parasite, is the causative agent of Chagas disease. Currently the species is divided into six taxonomic groups. The genome of the CL Brener clone has been estimated to be 106.4-110.7 Mb, and DNA content analyses revealed that it is a diploid hybrid clone. Trypanosoma rangeli is a hemoflagellate that has the same reservoirs and vectors as T. cruzi; however, it is non-pathogenic to vertebrate hosts. The haploid genome of T. rangeli was previously estimated to be 24 Mb. The parasitic strains of T. rangeli are divided into KP1(+) and KP1(-). Thus, the objective of this study was to investigate the DNA content in different strains of T. cruzi and T. rangeli by flow cytometry. All T. cruzi and T. rangeli strains yielded cell cycle profiles with clearly identifiable G1-0 (2n) and G2-M (4n) peaks. T. cruzi and T. rangeli genome sizes were estimated using the clone CL Brener and the Leishmania major CC1 as reference cell lines because their genome sequences have been previously determined. The DNA content of T. cruzi strains ranged from 87,41 to 108,16 Mb, and the DNA content of T. rangeli strains ranged from 63,25 Mb to 68,66 Mb. No differences in DNA content were observed between KP1(+) and KP1(-) T. rangeli strains. Cultures containing mixtures of the epimastigote forms of T. cruzi and T. rangeli strains resulted in cell cycle profiles with distinct G1 peaks for strains of each species. These results demonstrate that DNA content analysis by flow cytometry is a reliable technique for discrimination between T. cruzi and T. rangeli isolated from different hosts.

[Growth inhibition of the four species of red tide microalgae by extracts from Enteromorpha prolifera extracted with the five solvents].

PubMed

Sun, Ying-Ying; Liu, Xiao-Xiao; Wang, Chang-Hai

2010-06-01

To study the effects of extracts of Enteromorpha prolifera on the growth of the four species of red tide microalgae (Amphidinium hoefleri, Karenia mikimitoi, Alexandrium tamarense and Skeletonema costatum), the extracts were extracted with five solvents (methanol, acetone, ethyl acetate, chloroform and petroleum ether), respectively. Based on the observation of algal morphology and the measurement of algal density, cell size and the contents of physiological indicators (chlorophyll, protein and polysaccharide), the results showed methanol extracts of E. prolifera had the strongest action. The inhibitory effects of A. hoefleri, K. mikimitoi, A. tamarense and S. costatum by the methanol extracts were 54.0%, 48.1%, 44.0% and 37.5% in day 10, respectively. The extracts of E. prolifera extracted with methanol, acetone and ethyl acetate caused cavities, pieces and pigment reduction in cells, and those with chloroform and petroleum ether caused goffers on cells. The extracts of E. prolifera extracted with all the five solvents decreased athletic ability of the cells, among which those extracted with ethyl acetate, chloroform and petroleum ether decreased cell size of test microalgae. The further investigation found that the methanol extracts significantly decreased contents of chlorophyll, protein and polysaccharide in the cells of those microalgae. The inhibitory effect of chlorophyll, protein and polysaccharide contents of four species of microalgae by the methanol extracts was about 51%. On the basis of the above experiments, dry powder of E. prolifera were extracts with methanol, and extracts were obtained. The methanol extracts were partitioned to petroleum ether phase, ethyl acetate phase, n-butanol phase and distilled water phase by liquid-liquid fractionation, and those with petroleum ether and ethyl acetate significantly inhibited the growth of all test microalgae, and the inhibitory effect of four species of microalgae by those two extracts was above 25% in day 10. Our researches expressed that antialgal substances in E. prolifera extracted with methanol were obtained. And two fractions (petroleum ether phase and ethyl acetate phase) that inhibited the growth of all test microalgae were obtained when the methanol extracts was fractionated by liquid-liquid fractionation.

A study of the Al content impact on the properties of MmNi 4.4- xCo 0.6Al x alloys as precursors for negative electrodes in NiMH batteries

NASA Astrophysics Data System (ADS)

Bliznakov, S.; Lefterova, E.; Dimitrov, N.; Petrov, K.; Popov, A.

AB 5-type hydrogen storage alloys with MmNi 4.4- xCo 0.6Al x (Mm-mischmetal) composition are synthesized, structurally and thermodynamically characterized, and electrochemically tested in 6 M KOH electrolyte. It is shown that an increase of the Al content in the alloy results in expansion of both the alloy lattice cell size and the unit cell volume. These structural changes lead to decrease of the plateau pressure and increase of the plateau width in the pressure-composition-temperature desorption isotherms. Improvement of the specific electrode capacity is also registered with the increase of the cell parameters. In addition to that the higher Al content is found to enhance the stability of the alloy components' hydrides. Maximum discharge capacity of 278 mAh g -1 is measured with an electrode made from a MmNi 3.6Co 0.6Al 0.8 alloy. Cycle life tests of the accordingly prepared electrodes suggest a stability that is comparable to the stability of commercially available hydrogen storage electrodes.

Isolation of biologically active and morphologically intact exosomes from plasma of patients with cancer.

PubMed

Hong, Chang-Sook; Funk, Sonja; Muller, Laurent; Boyiadzis, Michael; Whiteside, Theresa L

2016-01-01

Isolation from human plasma of exosomes that retain functional and morphological integrity for probing their protein, lipid and nucleic acid content is a priority for the future use of exosomes as biomarkers. A method that meets these criteria and can be scaled up for patient monitoring is thus desirable. Plasma specimens (1 mL) of patients with acute myeloid leukaemia (AML) or a head and neck squamous cell carcinoma (HNSCC) were differentially centrifuged, ultrafiltered and fractionated by size exclusion chromatography in small disposable columns (mini-SEC). Exosomes were eluted in phosphate-buffered saline and were evaluated by qNano for particle size and counts, morphology by transmission electron microscopy, protein content, molecular profiles by western blots, and for ability to modify functions of immune cells. Exosomes eluting in fractions #3-5 had a diameter ranging from 50 to 200 nm by qNano, with the fraction #4 containing the bulk of clean, unaggregated exosomes. The exosome elution profiles remained constant for repeated runs of the same plasma. Larger plasma volumes could be fractionated running multiple mini-SEC columns in parallel. Particle concentrations per millilitre of plasma in #4 fractions of AML and HNSCC were comparable and were higher (p<0.003) than those in normal controls. Isolated AML exosomes co-incubated with normal human NK cells inhibited NKG2D expression levels (p<0.004), and HNSCC exosomes suppressed activation (p<0.01) and proliferation of activated T lymphocytes (p<0.03). Mini-SEC allows for simple and reproducible isolation from human plasma of exosomes retaining structural integrity and functional activity. It enables molecular/functional analysis of the exosome content in serial specimens of human plasma for clinical applications.

Isolation of a variant of Candida albicans.

PubMed Central

Buckley, H R; Price, M R; Daneo-Moore, L

1982-01-01

During the course of Candida albicans antigen production, a variant of this organism was encountered which did not produce hyphae at 37 degrees C. Presented here are some of the characteristics of this variant. It produces hyphae at 25 degrees C on cornmeal agar and synthetic medium plus N-acetylglucosamine and Tween 80. At 37 degrees C, it does not produce hyphae on these media, although C. albicans normally does produce hyphae under these circumstances. In liquid synthetic medium, this variant does not produce hyphae at 37 degrees C. The variant strain was analyzed for DNA, RNA, protein content, and particle size. After 50 to 70 h in balanced exponential-phase growth, particle size distribution was narrow, and there were no differences in the DNA, RNA, or protein content per particle in the two strains. When balanced exponential-phase cultures were brought into stationary phase, both strains contained the same amount of DNA per cell. Images PMID:6752021

Isolation of a variant of Candida albicans.

PubMed

Buckley, H R; Price, M R; Daneo-Moore, L

1982-09-01

During the course of Candida albicans antigen production, a variant of this organism was encountered which did not produce hyphae at 37 degrees C. Presented here are some of the characteristics of this variant. It produces hyphae at 25 degrees C on cornmeal agar and synthetic medium plus N-acetylglucosamine and Tween 80. At 37 degrees C, it does not produce hyphae on these media, although C. albicans normally does produce hyphae under these circumstances. In liquid synthetic medium, this variant does not produce hyphae at 37 degrees C. The variant strain was analyzed for DNA, RNA, protein content, and particle size. After 50 to 70 h in balanced exponential-phase growth, particle size distribution was narrow, and there were no differences in the DNA, RNA, or protein content per particle in the two strains. When balanced exponential-phase cultures were brought into stationary phase, both strains contained the same amount of DNA per cell.

Gold-coated polydimethylsiloxane microwells for high-throughput electrochemiluminescence analysis of intracellular glucose at single cells.

PubMed

Xia, Juan; Zhou, Junyu; Zhang, Ronggui; Jiang, Dechen; Jiang, Depeng

2018-06-04

In this communication, a gold-coated polydimethylsiloxane (PDMS) chip with cell-sized microwells was prepared through a stamping and spraying process that was applied directly for high-throughput electrochemiluminescence (ECL) analysis of intracellular glucose at single cells. As compared with the previous multiple-step fabrication of photoresist-based microwells on the electrode, the preparation process is simple and offers fresh electrode surface for higher luminescence intensity. More luminescence intensity was recorded from cell-retained microwells than that at the planar region among the microwells that was correlated with the content of intracellular glucose. The successful monitoring of intracellular glucose at single cells using this PDMS chip will provide an alternative strategy for high-throughput single-cell analysis. Graphical abstract ᅟ.

Nucleoli cytomorphology in cutaneous melanoma cells - a new prognostic approach to an old concept.

PubMed

Donizy, Piotr; Biecek, Przemyslaw; Halon, Agnieszka; Maciejczyk, Adam; Matkowski, Rafal

2017-12-29

The nucleolus is an organelle that is an ultrastructural element of the cell nucleus observed in H&E staining as a roundish body stained with eosin due to its high protein content. Changes in the nucleoli cytomorphology were one of the first histopathological characteristics of malignant tumors. The aim of this study was to assess the relationship between the cytomorphological characteristics of nucleoli and detailed clinicopathological parameters of melanoma patients. Moreover, we analyzed the correlation between cytomorphological parameters of nucleoli and immunoreactivity of selected proteins responsible for, among others, regulation of epithelial-mesenchymal transition (SPARC, N-cadherin), cell adhesion and motility (ALCAM, ADAM-10), mitotic divisions (PLK1), cellular survival (FOXP1) and the functioning of Golgi apparatus (GOLPH3, GP73). Three characteristics of nucleoli - presence, size and number - of cancer cells were assessed in H&E-stained slides of 96 formalin-fixed paraffin-embedded primary cutaneous melanoma tissue specimens. The results were correlated with classical clinicopathological features and patient survival. Immunohistochemical analysis of the above mentioned proteins was described in details in previous studies. Higher prevalence and size of nucleoli were associated with thicker and mitogenic tumors. All three nucleolar characteristics were related to the presence of ulceration. Moreover, microsatellitosis was strongly correlated with the presence of macronucleoli and polynucleolization (presence of two or more nucleoli). Lack of immunologic response manifested as no TILs in primary tumor was associated with high prevalence of melanoma cells with distinct nucleoli. Interestingly, in nodular melanoma a higher percentage of melanoma cells with prominent nucleoli was observed. In Kaplan-Meier analysis, increased prevalence and amount, but not size of nucleoli, were connected with shorter cancer-specific and disease-free survival. (1) High representation of cancer cells with distinct nucleoli, greater size and number of nucleoli per cell are characteristics of aggressive phenotype of melanoma; (2) higher prevalence and size of nucleoli are potential measures of cell kinetics that are strictly correlated with high mitotic rate; and (3) high prevalence of cancer cells with distinct nucleoli and presence of melanocytes with multiple nucleoli are features associated with unfavorable prognosis in patients with cutaneous melanoma.

[Effects of moxibustion with seed-sized moxa cone at "Ganshu" (BL 18) on liver function in rats with precancerous lesion of hepatic cellular cancer].

PubMed

Liu, Yang; Hou, Zhongwei; Lu, Jun; Dong, Feng; Wang, Pei; Jia, Wenrui; Wang, Chaoyang

2015-07-01

To explore the effects of moxibustion with seed-sized moxa cone at "Ganshu" (BL 18) on liver furiction and morphology in rat with precancerous lesion of hepatic cellular cancer MCC). A total of 60 male Wistar rats were randomly divided into a normal group (10 rats), a model group (20 rats), a 20-day treatment group (15 rats) and a 40-day treatment group (15 rats). HCC model was established by intraperitoneal injection of diethylnitrosamine (DEN). Rats in the normal group received no treatment. Rats in the model group were treated with fixation. Rats in the 20-day treatment group and 40-day treatment group were treated by moxibustion with seed-sized moxa cone at "Ganshu" (BL 18), once every other day, for 20 days and 40 days, respectively. Blood sample in each group was collected 1 d before model establishment, 20 d, 40 d and 84 d after model establishment. Chemical method was applied to test the activity of ALT (alamine aminotransferase), AST (aspartate transaminase) and GGT (glutamyl transpeptidase); at the end of model establishment, all the rats were sacrificed to observe the liver morphology changes. After the first therapeutic course, the. content of ALT and AST in the 20-day treatment group was significantly lower than that in the model group (all P<0. 05); after the second therapeutic course, the content of ALT, AST and GGT in the 40-day treatment group was insignificantly lower than that in the model group (all P>0. 05). Under light microscope, the slice of liver tissue indicated that primary tumor was induced in the model group, and the tumor cells were stained and irregular; the cytoplasm in the 20-day treatment group was even, and the tumor cells were few with several nodules alone. In the 40-day treatment group the liver morphology was normal and the staining was even; the tumor cells were few without nodules or a few. Conclusion Moxibustion with seed-sized moxa cone at "Ganshu" (BL 18) could reduce the serum content of ALT, AST and GGT in rats with HCC, which could protect the liver and: delay the DEN-induced precancerous lesion on some levels.

Large variability in synaptic N-methyl-D-aspartate receptor density on interneurons and a comparison with pyramidal-cell spines in the rat hippocampus.

PubMed

Nyíri, G; Stephenson, F A; Freund, T F; Somogyi, P

2003-01-01

Pyramidal cells receive input from several types of GABA-releasing interneurons and innervate them reciprocally. Glutamatergic activation of interneurons involves both alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) type glutamate receptors expressed in type I synapses, mostly on their dendritic shafts. On average, the synaptic AMPA receptor content is several times higher on interneurons than in the spines of pyramidal cells. To compare the NMDA receptor content of synapses, we used a quantitative postembedding immunogold technique on serial electron microscopic sections, and analysed the synapses on interneuron dendrites and pyramidal cell spines in the CA1 area. Because all NMDA receptors contain the obligatory NR1 subunit, receptor localisation was carried out using antibodies recognising all splice variants of the NR1 subunit. Four populations of synapse were examined: i). on spines of pyramidal cells in stratum (str.) radiatum and str. oriens; ii). on parvalbumin-positive interneuronal dendritic shafts in str. radiatum; iii). on randomly found dendritic shafts in str. oriens and iv). on somatostatin-positive interneuronal dendritic shafts and somata in str. oriens. On average, the size of the synapses on spines was about half of those on interneurons. The four populations of synapse significantly differed in labelling for the NR1 subunit. The median density of NR1 subunit labelling was highest on pyramidal cell spines. It was lowest in the synapses on parvalbumin-positive dendrites in str. radiatum, where more than half of these synapses were immunonegative. In str. oriens, synapses on interneurons had a high variability of receptor content; some dendrites were similar to those in str. radiatum, including the proximal synapses of somatostatin-positive cells, whereas others had immunoreactivity for the NR1 subunit similar to or higher than synapses on pyramidal cell spines. These results show that synaptic NMDA receptor density differs between pyramidal cells and interneurons. Some interneurons may have a high NMDA receptor content, whereas others, like some parvalbumin-expressing cells, a particularly low synaptic NMDA receptor content. Consequently, fast glutamatergic activation of interneurons is expected to show cell type-specific time course and state-dependent dynamics.

Nuclear DNA content variation in life history phases of the Bonnemasoniaceae (Rhodophyta).

PubMed

Salvador Soler, Noemi; Gómez Garreta, Amelia; Ribera Siguan, Ma Antonia; Kapraun, Donald F

2014-01-01

Nuclear DNA content in gametophytes and sporophytes or the prostrate phases of the following species of Bonnemaisoniaceae (Asparagopsis armata, Asparagopsis taxiformis, Bonnemaisonia asparagoides, Bonnemaisonia clavata and Bonnemaisonia hamifera) were estimated by image analysis and static microspectrophotometry using the DNA-localizing fluorochrome DAPI (4', 6-diamidino-2-phenylindole, dilactate) and the chicken erythrocytes standard. These estimates expand on the Kew database of DNA nuclear content. DNA content values for 1C nuclei in the gametophytes (spermatia and vegetative cells) range from 0.5 pg to 0.8 pg, and for 2C nuclei in the sporophytes or the prostrate phases range from 1.15-1.7 pg. Although only the 2C and 4C values were observed in the sporophyte or the prostrate phase, in the vegetative cells of the gametophyte the values oscillated from 1C to 4C, showing the possible start of endopolyploidy. The results confirm the alternation of nuclear phases in these Bonnemaisoniaceae species, in those that have tetrasporogenesis, as well as those that have somatic meiosis. The availability of a consensus phylogenetic tree for Bonnemaisoniaceae has opened the way to determine evolutionary trends in DNA contents. Both the estimated genome sizes and the published chromosome numbers for Bonnemaisoniaceae suggest a narrow range of values consistent with the conservation of an ancestral genome.

Tumor-derived exosomes in ovarian cancer – liquid biopsies for early detection and real-time monitoring of cancer progression

PubMed Central

Sharma, Shayna; Zuñiga, Felipe; Rice, Gregory E.; Perrin, Lewis C.; Hooper, John D.; Salomon, Carlos

2017-01-01

Ovarian cancer usually has a poor prognosis because it predominantly presents as high stage disease. New approaches are required to develop more effective early detection strategies and real-time treatment response monitoring. Nano-sized extracellular vesicles (EVs, including exosomes) may provide an approach to enrich tumor biomarker detection and address this clinical need. Exosomes are membranous extracellular vesicles of approximately 100 nm in diameter that have potential to be used as biomarkers and therapeutic delivery tools for ovarian cancer. Exosomal content (proteins and miRNA) is often parent cell specific thus providing an insight or “fingerprint” of the intracellular environment. Furthermore, exosomes can aid cell-cell communication and have the ability to modify target cells by transferring their content. Additionally, via the capacity to evade the immune system and remain stable over long periods in circulation, exosomes have potential as natural drug agents. This review examines the potential role of exosomes in diagnosis, drug delivery and real-time monitoring in ovarian cancer. PMID:29262670

Preparation of highly ordered mesoporous Al2O3/TiO2 and its application in dye-sensitized solar cells.

PubMed

Kim, Jae-Yup; Kang, Soon Hyung; Kim, Hyun Sik; Sung, Yung-Eun

2010-02-16

Highly ordered mesoporous Al(2)O(3)/TiO(2) was prepared by sol-gel reaction and evaporation-induced self-assembly (EISA) for use in dye-sensitized solar cells. The prepared materials had two-dimensional, hexagonal pore structures with anatase crystalline phases. The average pore size of mesoporous Al(2)O(3)/TiO(2) remained uniform and in the range of 6.33-6.58 nm while the Brunauer-Emmett-Teller (BET) surface area varied from 181 to 212 m(2)/g with increasing the content of Al(2)O(3). The incorporation of Al content retarded crystallite growth, thereby decreasing crystallite size while simultaneously improving the uniformity of pore size and volume. The thin Al(2)O(3) layer was located mostly on the mesopore surface, as confirmed by X-ray photoelectron spectroscopy (XPS). The Al(2)O(3) coating on the mesoporous TiO(2) film contributes to the essential energy barrier which blocks the charge recombination process in dye-sensitized solar cells. Mesoporous Al(2)O(3)/TiO(2) (1 mol % Al(2)O(3)) exhibited enhanced power conversion efficiency (V(oc) = 0.74 V, J(sc) = 15.31 mA/cm(2), fill factor = 57%, efficiency = 6.50%) compared to pure mesoporous TiO(2) (V(oc) = 0.72 V, J(sc) = 16.03 mA/cm(2), fill factor = 51%, efficiency = 5.88%). Therefore, the power conversion efficiency was improved by approximately 10.5%. In particular, the increase in V(oc) and fill factor resulted from the inhibition of charge recombination and the improvement of pore structure.

Comparison of toxicity of uncoated and coated silver nanoparticles

NASA Astrophysics Data System (ADS)

Nguyen, K. C.; Seligy, V. L.; Massarsky, A.; Moon, T. W.; Rippstein, P.; Tan, J.; Tayabali, A. F.

2013-04-01

This study compares toxic effects of uncoated (20, 40, 60 and 80 nm) and OECD (Organization for Economic Co-operation and Development) standard citrate- and polyvinylpyrrolidone (PVP)-coated (10, 50, and 75 nm) silver nanoparticles (Ag-NPs) in J774A. 1 macrophage and HT29 epithelial cells. The cells were exposed to different concentrations (silver content) of Ag-NPs for 24 h. Analysis showed that uncoated Ag-NPs, at a concentration of 1 μg/ml, decreased cell viability by 20-40% and that 20 and 40 nm particles were 10% more cytotoxic than the 60 and 80 nm particles. In exposures to coated Ag-NPs, cell viability dropped at 25 μg/ml or higher concentrations, and the effects were also size-dependent. PVP-coated particles induced greater cytotoxicity than citrate-coated particles. Changes in sub-cellular architecture were observed in J774A. 1 cells upon exposure to test Ag-NPs. Furthermore, uncoated Ag-NPs (1 μg/mL) decreased the expression of selected cytokines including TNF-α, IL-1β, and IL-12 (p70) in J774A. 1 and IL-8 in HT29 cells. In contrast, both citrate- and PVP-coated Ag-NPs increased the expression of these cytokines at higher concentrations (25 μg/ml), and PVP-coated particles elevated cytokine levels the most. Moreover, while uncoated Ag-NPs resulted in decreased glutathione (GSH) content and increased superoxide dismutase (SOD) activity in test cells in a size-dependent manner at 1 μg/ml, coated Ag-NPs caused non-significant changes in GSH and SOD, even at the highest test concentrations. Lastly, uncoated (20 and 40 nm) at 1 μg/ml and coated Ag-NPs (10 nm PVP) at 50 μg/ml slightly increased the production of reactive oxygen species (ROS). Our data showed that uncoated Ag-NPs are more toxic than coated Ag-NPs. While uncoated Ag-NPs appear to suppress inflammatory responses and enhance oxidative stress in the test cells, coated Ag-NPs induce toxic effects through up-regulation of cytokines. Our findings support the toxicity of Ag-NPs as being size- and coating- dependent while providing additional insight on the health impact of Ag-NPs.

Hornwort Stomata: Architecture and Fate Shared with 400-Million-Year-Old Fossil Plants without Leaves.

PubMed

Renzaglia, Karen S; Villarreal, Juan Carlos; Piatkowski, Bryan T; Lucas, Jessica R; Merced, Amelia

2017-06-01

As one of the earliest plant groups to evolve stomata, hornworts are key to understanding the origin and function of stomata. Hornwort stomata are large and scattered on sporangia that grow from their bases and release spores at their tips. We present data from development and immunocytochemistry that identify a role for hornwort stomata that is correlated with sporangial and spore maturation. We measured guard cells across the genera with stomata to assess developmental changes in size and to analyze any correlation with genome size. Stomata form at the base of the sporophyte in the green region, where they develop differential wall thickenings, form a pore, and die. Guard cells collapse inwardly, increase in surface area, and remain perched over a substomatal cavity and network of intercellular spaces that is initially fluid filled. Following pore formation, the sporophyte dries from the outside inwardly and continues to do so after guard cells die and collapse. Spore tetrads develop in spore mother cell walls within a mucilaginous matrix, both of which progressively dry before sporophyte dehiscence. A lack of correlation between guard cell size and DNA content, lack of arabinans in cell walls, and perpetually open pores are consistent with the inactivity of hornwort stomata. Stomata are expendable in hornworts, as they have been lost twice in derived taxa. Guard cells and epidermal cells of hornworts show striking similarities with the earliest plant fossils. Our findings identify an architecture and fate of stomata in hornworts that is ancient and common to plants without sporophytic leaves. © 2017 American Society of Plant Biologists. All Rights Reserved.

Protein Supplementation Augments Muscle Fiber Hypertrophy but Does Not Modulate Satellite Cell Content During Prolonged Resistance-Type Exercise Training in Frail Elderly.

PubMed

Dirks, Marlou L; Tieland, Michael; Verdijk, Lex B; Losen, Mario; Nilwik, Rachel; Mensink, Marco; de Groot, Lisette C P G M; van Loon, Luc J C

2017-07-01

Protein supplementation increases gains in lean body mass following prolonged resistance-type exercise training in frail older adults. We assessed whether the greater increase in lean body mass can be attributed to muscle fiber type specific hypertrophy with concomitant changes in satellite cell (SC) content. A total of 34 frail elderly individuals (77 ± 1 years, n = 12 male adults) participated in this randomized, double-blind, placebo-controlled trial with 2 arms in parallel. Participants performed 24 weeks of progressive resistance-type exercise training (2 sessions per week) during which they were supplemented twice-daily with milk protein (2 × 15 g) or a placebo. Muscle biopsies were taken at baseline, and after 12 and 24 weeks of intervention, to determine type I and type II muscle fiber specific cross-sectional area (CSA), SC content, and myocellular characteristics. In the placebo group, a trend for a 20% ± 11% increase in muscle fiber CSA was observed in type II fibers only (P = .051), with no increase in type I muscle fiber CSA. In the protein group, type I and II muscle fiber CSA increased by 23% ± 7% and 34% ± 10% following 6 months of training, respectively (P < .01). Myonuclear domain size increased over time in both groups and fiber types (P < .001), with no significant differences between groups (P > .05). No changes in myonuclear content and SC contents were observed over time in either group (both P > .05). Regression analysis showed that changes in myonuclear content and domain size are predictive of muscle fiber hypertrophy. Protein supplementation augments muscle fiber hypertrophy following prolonged resistance-type exercise training in frail older people, without changes in myonuclear and SC content. Copyright © 2017 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

Carbon content of common airborne fungal species and fungal contribution to aerosol organic carbon in a subtropical city

NASA Astrophysics Data System (ADS)

Cheng, Jessica Y. W.; Chan, Chak K.; Lee, C.-T.; Lau, Arthur P. S.

Interest in the role and contribution of fungi to atmospheric aerosols and processes grows in the past decade. Substantial data or information such as fungal mass or carbon loading to ambient aerosols is however still lacking. This study aimed to quantify the specific organic carbon content (OC per spore) of eleven fungal species commonly found airborne in the subtropics, and estimated their contribution to organic carbon in aerosols. The specific OC contents showed a size-dependent relationship ( r = 0.64, p < 0.05) and ranged from 3.6 to 201.0 pg carbon per spore or yeast cell, giving an average of 6.0 pg carbon per spore (RSD 51%) for spore or cell size less than 10 μm. In accounting for natural variations in the composition and abundance of fungal population, weighted-average carbon content for field samples was adopted using the laboratory determined specific OC values. An average of 5.97 pg carbon per spore (RSD 3.8%) was enumerated from 28 field samples collected at the university campus. The mean fungal OC concentration was 3.7, 6.0 and 9.7 ng m -3 in PM 2.5, PM 2.5-10 and PM 10, respectively. These corresponded to 0.1%, 1.2% and 0.2% of the total OC in PM 2.5, PM 2.5-10 and PM 10, respectively. In the study period, rain provided periods with low total OC but high fungal prevalence and fungi contributed 7-32% OC in PM 2.5-10 or 2.4-7.1% OC in PM 10. More extensive studies are deserved to better understand the spatial-, temporal- and episodic dependency on the fungal OC contribution to the atmospheric aerosols.

Feasibility of ceramic-polymer composite cryogels as scaffolds for bone tissue engineering.

PubMed

Rodriguez-Lorenzo, Luis M; Saldaña, Laura; Benito-Garzón, Lorena; García-Carrodeguas, Raul; de Aza, Salvador; Vilaboa, Nuria; Román, Julio San

2012-06-01

The purpose of the current study was to investigate whether the cryopolymerization technique is capable of producing suitable scaffolds for bone tissue engineering. Cryopolymers made of 2-hydroxyethyl methacrylate and acrylic acid with (W1 and W20) and without (W0) wollastonite particles were prepared. The elastic modulus of the specimens rose one order of magnitude from W1 to W20. Total porosity reached 56% for W0, 72% for W1 and 36% for W20, with pore sizes of up to 2 mm, large interconnection sizes of up to 1 mm and small interconnection sizes of 50-80 µm on dry specimens. Cryogels swell up to 224 ± 17% for W0, 315 ± 18% for W1 and 231 ± 27% for W20 specimens, while maintaining the integrity of the bodies. Pore sizes > 5 mm can be observed for swollen specimens. The biocompatibility of the samples was tested using human mesenchymal stem cells isolated from bone marrow and adipose tissues. Both types of cells attached and grew on the three tested substrates, colonized their inner regions and organized an extracellular cell matrix. Fibronectin and osteopontin levels decreased in the media from cells cultured on W20 samples, likely due to increased binding on the ECM deposited by cells. The osteoprotegerin-to-receptor activator of nuclear factor-κB ligand secretion ratios increased with increasing wollastonite content. Altogether, these results indicate that an appropriate balance of surface properties and structure that favours stromal cell colonization in the porous cryogels can be achieved by modulating the amount of wollastonite. Copyright © 2011 John Wiley & Sons, Ltd.

Collective cell migration during inflammatory response

NASA Astrophysics Data System (ADS)

Wu, Di; Stroka, Kimberly; Aranda-Espinoza, Helim

2012-02-01

Wound scratch healing assays of endothelial cell monolayers is a simple model to study collective cell migration as a function of biological signals. A signal of particular interest is the immune response, which after initial wounding in vivo causes the release of various inflammatory factors such as tumor necrosis alpha (TNF-α). TNF-α is an innate inflammatory cytokine that can induce cell growth, cell necrosis, and change cell morphology. We studied the effects of TNF-α on collective cell migration using the wound healing assays and measured several migration metrics, such as rate of scratch closure, velocities of leading edge and bulk cells, closure index, and velocity correlation functions between migrating cells. We observed that TNF-α alters all migratory metrics as a function of the size of the scratch and TNF-α content. The changes observed in migration correlate with actin reorganization upon TNF-α exposure.

Lignin Down-regulation of Zea mays via dsRNAi and Klason Lignin Analysis

PubMed Central

Park, Sang-Hyuck; Ong, Rebecca Garlock; Mei, Chuansheng; Sticklen, Mariam

2014-01-01

To facilitate the use of lignocellulosic biomass as an alternative bioenergy resource, during biological conversion processes, a pretreatment step is needed to open up the structure of the plant cell wall, increasing the accessibility of the cell wall carbohydrates. Lignin, a polyphenolic material present in many cell wall types, is known to be a significant hindrance to enzyme access. Reduction in lignin content to a level that does not interfere with the structural integrity and defense system of the plant might be a valuable step to reduce the costs of bioethanol production. In this study, we have genetically down-regulated one of the lignin biosynthesis-related genes, cinnamoyl-CoA reductase (ZmCCR1) via a double stranded RNA interference technique. The ZmCCR1_RNAi construct was integrated into the maize genome using the particle bombardment method. Transgenic maize plants grew normally as compared to the wild-type control plants without interfering with biomass growth or defense mechanisms, with the exception of displaying of brown-coloration in transgenic plants leaf mid-ribs, husks, and stems. The microscopic analyses, in conjunction with the histological assay, revealed that the leaf sclerenchyma fibers were thinned but the structure and size of other major vascular system components was not altered. The lignin content in the transgenic maize was reduced by 7-8.7%, the crystalline cellulose content was increased in response to lignin reduction, and hemicelluloses remained unchanged. The analyses may indicate that carbon flow might have been shifted from lignin biosynthesis to cellulose biosynthesis. This article delineates the procedures used to down-regulate the lignin content in maize via RNAi technology, and the cell wall compositional analyses used to verify the effect of the modifications on the cell wall structure. PMID:25080235

Lignin down-regulation of Zea mays via dsRNAi and klason lignin analysis.

PubMed

Park, Sang-Hyuck; Ong, Rebecca Garlock; Mei, Chuansheng; Sticklen, Mariam

2014-07-23

To facilitate the use of lignocellulosic biomass as an alternative bioenergy resource, during biological conversion processes, a pretreatment step is needed to open up the structure of the plant cell wall, increasing the accessibility of the cell wall carbohydrates. Lignin, a polyphenolic material present in many cell wall types, is known to be a significant hindrance to enzyme access. Reduction in lignin content to a level that does not interfere with the structural integrity and defense system of the plant might be a valuable step to reduce the costs of bioethanol production. In this study, we have genetically down-regulated one of the lignin biosynthesis-related genes, cinnamoyl-CoA reductase (ZmCCR1) via a double stranded RNA interference technique. The ZmCCR1_RNAi construct was integrated into the maize genome using the particle bombardment method. Transgenic maize plants grew normally as compared to the wild-type control plants without interfering with biomass growth or defense mechanisms, with the exception of displaying of brown-coloration in transgenic plants leaf mid-ribs, husks, and stems. The microscopic analyses, in conjunction with the histological assay, revealed that the leaf sclerenchyma fibers were thinned but the structure and size of other major vascular system components was not altered. The lignin content in the transgenic maize was reduced by 7-8.7%, the crystalline cellulose content was increased in response to lignin reduction, and hemicelluloses remained unchanged. The analyses may indicate that carbon flow might have been shifted from lignin biosynthesis to cellulose biosynthesis. This article delineates the procedures used to down-regulate the lignin content in maize via RNAi technology, and the cell wall compositional analyses used to verify the effect of the modifications on the cell wall structure.

Imaging of Lipids in Microalgae with Coherent Anti-Stokes Raman Scattering Microscopy1[OPEN

PubMed Central

Cavonius, Lillie; Fink, Helen; Kiskis, Juris; Albers, Eva; Undeland, Ingrid; Enejder, Annika

2015-01-01

Microalgae have great prospects as a sustainable resource of lipids for refinement into nutraceuticals and biodiesel, which increases the need for detailed insights into their intracellular lipid synthesis/storage mechanisms. As an alternative strategy to solvent- and label-based lipid quantification techniques, we introduce time-gated coherent anti-Stokes Raman scattering (CARS) microscopy for monitoring lipid contents in living algae, despite strong autofluorescence from the chloroplasts, at approximately picogram and subcellular levels by probing inherent molecular vibrations. Intracellular lipid droplet synthesis was followed in Phaeodactylum tricornutum algae grown under (1) light/nutrient-replete (control [Ctrl]), (2) light-limited (LL), and (3) nitrogen-starved (NS) conditions. Good correlation (r2 = 0.924) was found between lipid volume data yielded by CARS microscopy and total fatty acid content obtained from gas chromatography-mass spectrometry analysis. In Ctrl and LL cells, micron-sized lipid droplets were found to increase in number throughout the growth phases, particularly in the stationary phase. During more excessive lipid accumulation, as observed in NS cells, promising commercial harvest as biofuels and nutritional lipids, several micron-sized droplets were present already initially during cultivation, which then fused into a single giant droplet toward stationary phase alongside with new droplets emerging. CARS microspectroscopy further indicated lower lipid fluidity in NS cells than in Ctrl and LL cells, potentially due to higher fatty acid saturation. This agreed with the fatty acid profiles gathered by gas chromatography-mass spectrometry. CARS microscopy could thus provide quantitative and semiqualitative data at the single-cell level along with important insights into lipid-accumulating mechanisms, here revealing two different modes for normal and excessive lipid accumulation. PMID:25583924

No cytotoxicity or genotoxicity of graphene and graphene oxide in murine lung epithelial FE1 cells in vitro

PubMed Central

Bengtson, Stefan; Kling, Kirsten; Madsen, Anne Mette; Noergaard, Asger W.; Jacobsen, Nicklas Raun; Clausen, Per Axel; Alonso, Beatriz; Pesquera, Amaia; Zurutuza, Amaia; Ramos, Raphael; Okuno, Hanako; Dijon, Jean; Wallin, Håkan

2016-01-01

Graphene and graphene oxide receive much attention these years, because they add attractive properties to a wide range of applications and products. Several studies have shown toxicological effects of other carbon‐based nanomaterials such as carbon black nanoparticles and carbon nanotubes in vitro and in vivo. Here, we report in‐depth physicochemical characterization of three commercial graphene materials, one graphene oxide (GO) and two reduced graphene oxides (rGO) and assess cytotoxicity and genotoxicity in the murine lung epithelial cell line FE1. The studied GO and rGO mainly consisted of 2–3 graphene layers with lateral sizes of 1–2 µm. GO had almost equimolar content of C, O, and H while the two rGO materials had lower contents of oxygen with C/O and C/H ratios of 8 and 12.8, respectively. All materials had low levels of endotoxin and low levels of inorganic impurities, which were mainly sulphur, manganese, and silicon. GO generated more ROS than the two rGO materials, but none of the graphene materials influenced cytotoxicity in terms of cell viability and cell proliferation after 24 hr. Furthermore, no genotoxicity was observed using the alkaline comet assay following 3 or 24 hr of exposure. We demonstrate that chemically pure, few‐layered GO and rGO with comparable lateral size (> 1 µm) do not induce significant cytotoxicity or genotoxicity in FE1 cells at relatively high doses (5–200 µg/ml). Environ. Mol. Mutagen. 57:469–482, 2016. © 2016 The Authors. Environmental and Molecular Mutagenesis Published by Wiley Periodicals, Inc. PMID:27189646

Comparative physicochemical and biological characterization of NIST Interim Reference Material PM2.5 and SRM 1648 in human A549 and mouse RAW264.7 cells.

PubMed

Mitkus, Robert J; Powell, Jan L; Zeisler, Rolf; Squibb, Katherine S

2013-12-01

The epidemiological association between exposure to fine particulate matter (PM2.5) and adverse health effects is well-known. Here we report the size distribution, metals content, endotoxin content, and biological activity of National Institute of Standards and Technology (NIST) Interim Reference Material (RM) PM2.5. Biological activity was measured in vitro by effects on cell viability and the release of four inflammatory immune mediators, from human A549 alveolar epithelial cells or murine RAW264.7 monocytes. A dose range covering three orders of magnitude (1-1000μg/mL) was tested, and biological activity was compared to an existing Standard Reference Material (SRM) for urban PM (NIST SRM 1648). Robust release of IL-8 and MCP-1 from A549 cells was observed in response to IRM PM2.5 exposures. Significant TNF-α, but not IL-6, secretion from RAW264.7 cells was observed in response to both IRM PM2.5 and SRM 1648 particle types. Cytokine or chemokine release at high doses often occurred in the presence of cytotoxicity, likely as a result of externalization of preformed mediator. Our results are consistent with a local cytotoxic and pro-inflammatory mechanism of response to exposure to inhaled ambient PM2.5 and reinforce the continued relevance of in vitro assays for mechanistic research in PM toxicology. Our study furthers the goal of developing reference samples of environmentally relevant particulate matter of various sizes that can be used for hypothesis testing by multiple investigators. Published by Elsevier Ltd.

Sorting of Streptomyces Cell Pellets Using a Complex Object Parametric Analyzer and Sorter

PubMed Central

Petrus, Marloes L. C.; van Veluw, G. Jerre; Wösten, Han A. B.; Claessen, Dennis

2014-01-01

Streptomycetes are filamentous soil bacteria that are used in industry for the production of enzymes and antibiotics. When grown in bioreactors, these organisms form networks of interconnected hyphae, known as pellets, which are heterogeneous in size. Here we describe a method to analyze and sort mycelial pellets using a Complex Object Parametric Analyzer and Sorter (COPAS). Detailed instructions are given for the use of the instrument and the basic statistical analysis of the data. We furthermore describe how pellets can be sorted according to user-defined settings, which enables downstream processing such as the analysis of the RNA or protein content. Using this methodology the mechanism underlying heterogeneous growth can be tackled. This will be instrumental for improving streptomycetes as a cell factory, considering the fact that productivity correlates with pellet size. PMID:24561666

The determination of the real nano-scale sizes of bacteria in chernozem during microbial succession by means of hatching of a soil in aerobic and anaerobic conditions

NASA Astrophysics Data System (ADS)

Gorbacheva, M.

2012-04-01

M.A. Gorbacheva,L.M. Polyanskaya The Faculty of Soil Science, Moscow State University, Leninskie Gory, GSP-1, Moscow,119991,Russia In recent years there's been particular attention paid to the smallest life's forms- bacteria which size can be measured in nanometer. These are the forms of bacteria with diameter of 5-200 nm. Theoretical calculations based on the content of the minimum number of DNA, enzyme, lipids in and ribosome in cells indicates impossibility of existence of a living cells within diameter less than 300 nm. It is theoretically possible for a living cell to exist within possible diameter of approximately 140 nm. Using a fluorescence microscope there's been indicated in a number of samples from lakes, rivers, soil, snow and rain water that 200 nm is the smallest diameter of a living cell. Supposingly, such a small size of bacteria in soil is determined by natural conditions which limit their development by nutritious substances and stress-factors. Rejuvenescence of nanobacteria under unfavourable natural conditions and stress-factors is studied in laboratory environment. The object of the current study has become the samples of typical arable chernozem of the Central Chernozem State Biosphere Reserve in Kursk. The detailed morphological description of the soil profile and its basic analytical characteristics are widely represented in scientific publications. The soil is characterized by a high carbon content which makes up 3,96% ,3,8% , and 2,9% for the upper layers of the A horizon, and 0,79% for the layer of the B horizon. A microbial succession was studied under aerobic and anaerobic conditions by means of experiments with microcosms in upper A horizons and B horizon of a chernozem. The final aim is to identify the cells size of bacteria in aerobic and anaerobic soil conditions in chernozem during the microbial succession, by dampening and application of chitin by means of «cascade filtration» method. The study of the microcosms is important for understanding natural mechanisms in soil and will be useful for the development of new soil models in laboratory. Thus, by means of «cascade filtration» method there've been made some results on true size, quantity and biomass of bacteria. Development of a bacteria in various soil horizons and their layers in aerobic and anaerobic conditions and calculations of biomass of bacteria in upper layer horizon A and lower layer horizon B have also become the subjects of the studies. It was identified that the quantity of bacteria in aerobic conditions increase during the microbial succession while bacteria sized 230 and 380 nm were dominating. In anaerobic conditions the process of connecting cells sized 170 nm and bacteria is observed. Biomass of bacteria is higher in anaerobic conditions in upper layer horizon A because of elevated variety of bacteria. In horizon B in anaerobic conditions it is of maximum because of anaerobic situation in situ. Thus, distribution of bacteria's size depends on aeration of soil. That helps to acknowledge the receipt of theory of a great number of researchers about that fact that the size of bacteria in the soil in anaerobic conditions decrease under stress-factors. This work touches upon such a poorly investigated subject as nanobacteria in the soil. But this knowledge plays a significant role in land reclamation oil-cut and prognostication pollution of the soil by pathogenic bacteria.

Advanced nickel-metal hydride cell development. Final report, September 1993--March 1996

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

Lim, Hong S.

1996-03-01

Inert gas atomization using metal hydride alloys for a Ni/MH{sub x}cell was studied. Atomization of the alloys was demonstrated on a small production scale up to batch size of several kg. Relative performance of the atomized and nonatomized alloys was investigated for the electrode material in a Ni/MH{sub x} cell. The study included effects of charge-discharge rates, temperature, and particle size on cell voltage (polarization) and specific capacity. Results show that the specific capacity of the present atomized alloys was apprecialy smaller than that of the nonatomized powder, especially for initial cycles. Full activation of the atomized alloys oftentook severalmore » hundreds of cycles. However, no appreciable difference in discharge rate capability was observed with R10 and R12 alloys. Chemical compositions were indistinguishable, although the oxygen contents of the atomized alloys were always higher. Effects of Ni and Cu coating on alloy performance were studied after electroless coating; the coatings noticeably improved the electrode rate capability for all the alloys. The electrode polarization was esecially improved, but not the cycle life. Further studies are needed.« less

Inkjet formation of unilamellar lipid vesicles for cell-like encapsulation†

PubMed Central

Stachowiak, Jeanne C.; Richmond, David L.; Li, Thomas H.; Brochard-Wyart, Françoise

2010-01-01

Encapsulation of macromolecules within lipid vesicles has the potential to drive biological discovery and enable development of novel, cell-like therapeutics and sensors. However, rapid and reliable production of large numbers of unilamellar vesicles loaded with unrestricted and precisely-controlled contents requires new technologies that overcome size, uniformity, and throughput limitations of existing approaches. Here we present a high-throughput microfluidic method for vesicle formation and encapsulation using an inkjet printer at rates up to 200 Hz. We show how multiple high-frequency pulses of the inkjet’s piezoelectric actuator create a microfluidic jet that deforms a bilayer lipid membrane, controlling formation of individual vesicles. Variations in pulse number, pulse voltage, and solution viscosity are used to control the vesicle size. As a first step toward cell-like reconstitution using this method, we encapsulate the cytoskeletal protein actin and use co-encapsulated microspheres to track its polymerization into a densely entangled cytoskeletal network upon vesicle formation. PMID:19568667

The role of microvesicles in malignancies.

PubMed

Pap, Erna

2011-01-01

Microvesicles are membrane-covered cell fragments whose size varies between 30 and 1,000 nm. They are generated by all cell types, constituvely and in response to activation signals. Their importance in intercellular communication has been only recently discovered. They seem to enhance the potential of information transfer between cells, displaying a large number of proteins and lipids as membrane constituents and as components of the inner vesicular content. The content reflects the phenotype of the donor cell and allows the identification of the microvesicular origine as well. Complex "packets" of molecules are transmitted to the target cells this way, modifying their cellular physiology. Additionally, epigenetic changes may be induced by transmitted DNA and RNAs, that have also been identified in these vesicles. The vesicles can act in close and far distances as well. Microvesicles have been implicated in several physiological and pathological processes. There is an increasing evidence, that they play a pivotal role in tumorigenesis. Vesicles shedding from tumor cells reflect the special potential of the tumor for survival and expansion, independently from cell-to-cell contact. Tumor derived vesicles are fully equipped to facilitate the escape of tumor cells from immune surveillance through their protein and RNA content, at the same time they are involved in the establishment of an optimal environment for newly formed and metastatic tumor cells, influencing angiogenesis and the reorganization of the extracellular matrix. As immune cells, endothels, platelets and stem cells also release microvesicles, a multilevel communication network draws up, allowing a complex interplay between the cells. The concentration of tumor derived vesicles increases in blood plasma and other body fluids with the progression of the disease; therefor they may serve as prognostic markers. The microvesicular approach can offer new perspectives: interfering with the formation, release and propagation of these vesicles, they can be considered as new targets in tumor therapy.

The effect of crumb rubber particle size to the optimum binder content for open graded friction course.

PubMed

Ibrahim, Mohd Rasdan; Katman, Herda Yati; Karim, Mohamed Rehan; Koting, Suhana; Mashaan, Nuha S

2014-01-01

The main objective of this paper is to investigate the relations of rubber size, rubber content, and binder content in determination of optimum binder content for open graded friction course (OGFC). Mix gradation type B as specified in Specification for Porous Asphalt produced by the Road Engineering Association of Malaysia (REAM) was used in this study. Marshall specimens were prepared with four different sizes of rubber, namely, 20 mesh size [0.841 mm], 40 mesh [0.42 mm], 80 mesh [0.177 mm], and 100 mesh [0.149 mm] with different concentrations of rubberised bitumen (4%, 8%, and 12%) and different percentages of binder content (4%-7%). The appropriate optimum binder content is then selected according to the results of the air voids, binder draindown, and abrasion loss test. Test results found that crumb rubber particle size can affect the optimum binder content for OGFC.

Detection of early changes in lung cell cytology by flow-systems analysis techniques. Progress report, January 1--December 31, 1978. [Resulting from exposure to toxic agents associated with production and use of synthetic fuels from oil shale and coal

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

Steinkamp, J.A.; Wilson, J.S.; Svitra, Z.V.

1979-02-01

This report summarizes ongoing experiments to develop cytological and biochemical indicators for measuring damage to respiratory tract cells of experimental animals exposed by inhalation to environmental toxic agents. The specific goal is to apply flow cytometric methods to analyze and detect changes in lung epithelium as a function of exposure to toxic agents associated with the production and utilization of synthetic fuels from oil shale and coal. During the past 6 months, hamsters were exposed to raw and spent oil shale particulates, silica dust, and ozone, and DNA content measurements were performed on lung cell samples. Although initial shale exposuresmore » did not yield the expected results, recent data show atypical changes in DNA content per cell distributions. Ozone exposures also were expanded to include DNA measurements and cytology, ranging up to 72 h postexposure. Progress was achieved in developing a new method for quantitating pulmonary macrophage phagocytosis in rats using micron-sized fluorescent spheres. New methods for determining alkaline phosphatase, DNA content, and protein also were under development. Plans are to continue developing cytological and biochemical markers for measuring atypical cellular changes, including macrophage function, and to emphasize exposing experimental animals to particulates and gaseous agents for studying dose-damage relationships.« less

Quantitative characterization of the protein contents of the exocrine pancreatic acinar cell by soft x-ray microscopy and advanced digital imaging methods

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

Loo, Jr., Billy W.

2000-06-01

The study of the exocrine pancreatic acinar cell has been central to the development of models of many cellular processes, especially of protein transport and secretion. Traditional methods used to examine this system have provided a wealth of qualitative information from which mechanistic models have been inferred. However they have lacked the ability to make quantitative measurements, particularly of the distribution of protein in the cell, information critical for grounding of models in terms of magnitude and relative significance. This dissertation describes the development and application of new tools that were used to measure the protein content of the majormore » intracellular compartments in the acinar cell, particularly the zymogen granule. Soft x-ray microscopy permits image formation with high resolution and contrast determined by the underlying protein content of tissue rather than staining avidity. A sample preparation method compatible with x-ray microscopy was developed and its properties evaluated. Automatic computerized methods were developed to acquire, calibrate, and analyze large volumes of x-ray microscopic images of exocrine pancreatic tissue sections. Statistics were compiled on the protein density of several organelles, and on the protein density, size, and spatial distribution of tens of thousands of zymogen granules. The results of these measurements, and how they compare to predictions of different models of protein transport, are discussed.« less

Electrolyte management considerations in modern nickel/hydrogen and nickel/cadmium cell and battery designs

NASA Astrophysics Data System (ADS)

Thaller, Lawrence H.; Zimmerman, Albert H.

In the early 1980s, the battery group at the NASA Lewis Research Center (LeRC) reviewed the design issues associated with nickel/hydrogen cells for low-earth orbit applications. In 1984, these issues included gas management, liquid management, plate expansion, and the recombination of oxygen during overcharge. The design effort by that group followed principles set forth in an earlier LeRC paper that introduced the topic of pore size engineering. Also in 1984, the beneficial effect of lower electrolyte concentrations on cycle life was verified by Hughes Aircraft as part of a LeRC-funded study. Subsequent life cycle tests of these concepts have been carried out that essentially have verified all of this earlier work. During the past decade, some of the mysteries involved in the active material of the nickel electrode have been resolved by careful research done at several laboratories. While attention has been paid to understanding and modeling abnormal nickel/hydrogen cell behaviors, not enough attention has been paid to the potassium ion content in these cells, and more recently, in batteries. Examining the potassium ion content of different portions of the cell or battery is a convenient way of following the conductivity, mass transport properties, and electrolyte volume in each of the cell or battery portions under consideration. Several of the consequences of solvent and solute changes within fuel cells have been well known for some time. However, only recently have these consequences been applied to nickel/hydrogen and nickel/cadmium cell designs. As a result of these studies, several unusual cell performance signatures can now be satisfactorily explained in terms of movement of the solvent and solute components in the electrolyte. This paper will review three general areas where the potassium ion content can impact the performance and life of nickel/hydrogen and nickel/cadmium cells. Sample calculations of the concentration or volume changes that can take place within operating cells will be presented. With the aid of an accurate model of an operating cell or battery, the impact of changes of potassium ion content within a potential cell design can be estimated. All three of these areas are directly related to the volume tolerance and pore size engineering aspects of the components used in the cell or battery design. The three areas follow. (i) The gamma phase uptake of potassium ion can result in a lowering of the electrolyte concentration. This leads to a higher electrolyte resistance as well as electrolyte diffusional limitations on the discharge rate. This phenomenon also impacts the response of the cell to a reconditioning cycle. (ii) The transport of water vapor from a warmer to a cooler portion of the cell or battery under the driving force of a vapor pressure gradient has already impacted cells when water vapor condenses on a colder cell wall. This paper will explore the convective and diffusive movement of gases saturated with water vapor from a warmer plate pack to a cooler one, both with and without liquid communication. (iii) The impact of low-level shunt currents in multicell configurations results in the net movement of potassium hydroxide from one part of the battery to another. This movement impacts the electrolyte volume/vapor pressure relationships within the cell or battery.

Analysis of aging in lager brewing yeast during serial repitching.

PubMed

Bühligen, Franziska; Lindner, Patrick; Fetzer, Ingo; Stahl, Frank; Scheper, Thomas; Harms, Hauke; Müller, Susann

2014-10-10

Serial repitching of brewing yeast inoculates is an important economic factor in the brewing industry, as their propagation is time and resource intensive. Here, we investigated whether replicative aging and/or the population distribution status changed during serial repitching in three different breweries with the same brewing yeast strain but different abiotic backgrounds and repitching regimes with varying numbers of reuses. Next to bud scar numbers the DNA content of the Saccharomyces pastorianus HEBRU cells was analyzed. Gene expression patterns were investigated using low-density microarrays with genes for aging, stress, storage compound metabolism and cell cycle. Two breweries showed a stable rejuvenation rate during serial repitching. In a third brewery the fraction of virgin cells varied, which could be explained with differing wort aeration rates. Furthermore, the number of bud scars per cell and cell size correlated in all 3 breweries throughout all runs. Transcriptome analyses revealed that from the 6th run on, mainly for the cells positive gene expression could be seen, for example up-regulation of trehalose and glycogen metabolism genes. Additionally, the cells' settling in the cone was dependent on cell size, with the lowest and the uppermost cone layers showing the highest amount of dead cells. In general, cells do not progressively age during extended serial repitching. Copyright © 2014 Elsevier B.V. All rights reserved.

Variation, Evolution, and Correlation Analysis of C+G Content and Genome or Chromosome Size in Different Kingdoms and Phyla

PubMed Central

Li, Xiu-Qing; Du, Donglei

2014-01-01

C+G content (GC content or G+C content) is known to be correlated with genome/chromosome size in bacteria but the relationship for other kingdoms remains unclear. This study analyzed genome size, chromosome size, and base composition in most of the available sequenced genomes in various kingdoms. Genome size tends to increase during evolution in plants and animals, and the same is likely true for bacteria. The genomic C+G contents were found to vary greatly in microorganisms but were quite similar within each animal or plant subkingdom. In animals and plants, the C+G contents are ranked as follows: monocot plants>mammals>non-mammalian animals>dicot plants. The variation in C+G content between chromosomes within species is greater in animals than in plants. The correlation between average chromosome C+G content and chromosome length was found to be positive in Proteobacteria, Actinobacteria (but not in other analyzed bacterial phyla), Ascomycota fungi, and likely also in some plants; negative in some animals, insignificant in two protist phyla, and likely very weak in Archaea. Clearly, correlations between C+G content and chromosome size can be positive, negative, or not significant depending on the kingdoms/groups or species. Different phyla or species exhibit different patterns of correlation between chromosome-size and C+G content. Most chromosomes within a species have a similar pattern of variation in C+G content but outliers are common. The data presented in this study suggest that the C+G content is under genetic control by both trans- and cis- factors and that the correlation between C+G content and chromosome length can be positive, negative, or not significant in different phyla. PMID:24551092

Variation of Geochemical Signatures and Correlation of Biomarkers in Icelandic Mars Analogue Environments

NASA Astrophysics Data System (ADS)

Gentry, D.; Amador, E. S.; Cable, M. L.; Cantrell, T.; Chaudry, N.; Cullen, T.; Duca, Z. A.; Jacobsen, M. B.; McCaig, H. C.; Murukesan, G.; Rennie, V.; Schwieterman, E. W.; Stevens, A. H.; Tan, G.; Yin, C.; Stockton, A.; Cullen, D.; Geppert, W.

2015-12-01

Exploration missions to Mars rely on rovers to perform deep analyses over small sampling areas; however, landing site selection is done using large-scale but low-resolution remote sensing data. Using Earth analogue environments to estimate the small-scale spatial and temporal distributions of key geochemical signatures and (for habitability studies) biomarkers helps ensure that the chosen sampling strategies meet mission science goals. We conducted two rounds of analogue expeditions to recent Icelandic lava fields. In July 2013, we tested correlation between three common biomarker assays: cell quantification via fluorescence microscopy, ATP quantification via bioluminescence, and quantitative PCR with universal primer sets. Sample sites were nested at four spatial scales (1 m, 10 m, 100 m, and > 1 km) and homogeneous at 'remote imaging' resolution (overall temperature, apparent moisture content, and regolith grain size). All spatial scales were highly diverse in ATP, bacterial 16S, and archaeal 16S DNA content; nearly half of sites were statistically different in ATP content at α = 0.05. Cell counts showed significant variation at the 10 m and 100 m scale; at the > 1 km scale, the mean counts were not distinguishable, but the median counts were, indicating differences in underlying distribution. Fungal 18S DNA content similarly varied at 1 m, 10 m, and 100 m scales only. Cell counts were not correlated with ATP or DNA content at any scale. ATP concentration and DNA content for all three primer sets were positively correlated. Bacterial DNA content was positively correlated with archaeal and fungal DNA content, though archaeal correlation was weak. Fungal and archaeal correlation was borderline. In July 2015, we repeated the sampling strategy, with the addition of a smaller-scale sampling grid of 10 cm and a third > 1 km location. This expedition also measured reflectance of the tephra cover and preserved mineral samples for future Raman spectroscopy in order to better distinguish between effects of geochemical variation and intrinsic biomarker variation.

BSC-1 growth inhibitor transforms a mitogenic stimulus into a hypertrophic stimulus for renal proximal tubular cells: relationship to Na/sup +//H/sup +/ antiport activity

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

Fine, L.G.; Holley, R.W.; Nasri, H.

Renal hypertrophy is characterized by an increase in cell size and protein content with minimal hyperplasia. The mechanisms of control of this pattern of cell growth have not been determined. The present studies examined whether the growth inhibitor elaborated by BSC-1 kidney epilethal cells (GI), which has nearly identical biological properties to transforming growth factor ..beta.. (TGF-..beta..), could transform a mitogenic stimulus into a hypertrophic stimulus for rabbit renal proximal tubular cells in primary culture. Insulin plus hydrocortisone increased the amount of protein per cell, cell volume, and (/sup 3/H)thymidine incorporation at 24 and 48 hr in these cells. Whenmore » added together with insulin plus hydrocortisone, GI/TGF-..beta.. inhibited the stimulatory effect of these mitogens on (/sup 3/H)thymidine incorporation but did not block the increase in protein per cell and cell volume - i.e., the cells underwent hypertrophy. The fact that this pattern persisted for 48 hr indicated that GI/TGF-..beta.. exerted a prolonged inhibitory effect on mitogenic-stimulated DNA synthesis rather than delaying its onset. Amiloride-sensitive Na/sup +/ uptake using /sup 22/Na/sup +/ as a tracer, correlated with protein per cell and cell volume rather than with DNA synthesis. These studies indicate that the control of cell size may be regulated by autocrine mechanisms mediated by the elaboration of growth inhibitory factors that alter the pattern of the growth response to mitogens.« less

Toxicity of TiO2 Nanoparticles to Escherichia coli: Effects of Particle Size, Crystal Phase and Water Chemistry

PubMed Central

Lin, Xiuchun; Li, Jingyi; Ma, Si; Liu, Gesheng; Yang, Kun; Tong, Meiping; Lin, Daohui

2014-01-01

Controversial and inconsistent results on the eco-toxicity of TiO2 nanoparticles (NPs) are commonly found in recorded studies and more experimental works are therefore warranted to elucidate the nanotoxicity and its underlying precise mechanisms. Toxicities of five types of TiO2 NPs with different particle sizes (10∼50 nm) and crystal phases were investigated using Escherichia coli as a test organism. The effect of water chemistry on the nanotoxicity was also examined. The antibacterial effects of TiO2 NPs as revealed by dose-effect experiments decreased with increasing particle size and rutile content of the TiO2 NPs. More bacteria could survive at higher solution pH (5.0–10.0) and ionic strength (50–200 mg L−1 NaCl) as affected by the anatase TiO2 NPs. The TiO2 NPs with anatase crystal structure and smaller particle size produced higher content of intracellular reactive oxygen species and malondialdehyde, in line with their greater antibacterial effect. Transmission electron microscopic observations showed the concentration buildup of the anatase TiO2 NPs especially those with smaller particle sizes on the cell surfaces, leading to membrane damage and internalization. These research results will shed new light on the understanding of ecological effects of TiO2 NPs. PMID:25310452

Gentamicin Sulfate PEG-PLGA/PLGA-H Nanoparticles: Screening Design and Antimicrobial Effect Evaluation toward Clinic Bacterial Isolates

PubMed Central

Dorati, Rossella; DeTrizio, Antonella; Spalla, Melissa; Migliavacca, Roberta; Pagani, Laura; Pisani, Silvia; Chiesa, Enrica; Modena, Tiziana; Genta, Ida

2018-01-01

Nanotechnology is a promising approach both for restoring or enhancing activity of old and conventional antimicrobial agents and for treating intracellular infections by providing intracellular targeting and sustained release of drug inside infected cells. The present paper introduces a formulation study of gentamicin loaded biodegradable nanoparticles (Nps). Solid-oil-in water technique was studied for gentamicin sulfate nanoencapsulation using uncapped Polylactide-co-glycolide (PLGA-H) and Polylactide-co-glycolide-co-Polyethylenglycol (PLGA-PEG) blends. Screening design was applied to optimize: drug payload, Nps size and size distribution, stability and resuspendability after freeze-drying. PLGA-PEG concentration resulted most significant factor influencing particles size and drug content (DC): 8 w/w% DC and 200 nm Nps were obtained. Stirring rate resulted most influencing factor for size distribution (PDI): 700 rpm permitted to obtain homogeneous Nps dispersion (PDI = 1). Further experimental parameters investigated, by 23 screening design, were: polymer blend composition (PLGA-PEG and PLGA-H), Polyvinylalcohol (PVA) and methanol concentrations into aqueous phase. Drug content was increased to 10.5 w/w%. Nanoparticle lyophilization was studied adding cryoprotectants, polyvinypirrolidone K17 and K32, and sodiumcarboxymetylcellulose. Freeze-drying protocol was optimized by a mixture design. A freeze-dried Nps powder free resuspendable with stable Nps size and payload, was developed. The powder was tested on clinic bacterial isolates demonstrating that after encapsulation, gentamicin sulfate kept its activity. PMID:29329209

Synthesis, characterization and cell behavior of fluoridated hydroxyapatite

NASA Astrophysics Data System (ADS)

Qu, Haibo

Fluorine-containing hydroxyapatite (Ca5(PO4) 3(OH)1-xFx FHA), where F- partially replaces OH- in hydroxyapatite (HA), is recognized as a possible biomaterial for bone and tooth implants and gaining attention in the last several years as a possible alternative to HA. In this study, FHA powders were synthesized through a pH-cycling method. It was discovered that fluorine incorporation increased with the fluorine content in the initial solution and the number of pH cycles employed. A relatively low fluorine incorporation efficiency, ˜60%, was attained for most of the FHA samples. The short time of stay at each pH cycle and the limited number of cycles used are believed to be the main reasons of the low fluorine incorporation into the apatite structure. It was also revealed that the FHA particles produced by the pH-cycling method were inhomogeneous. They were a mixture of hydroxyapatite and F-rich apatite (or FA) particles. The mechanisms of incorporation of fluorine ions into hydroxyapatite by a pH cyclicing method were studied using TEM, XRD and fluorine measurement. Instead of forming laminated structures as reported by other research groups, a mixture of nano-sized F-rich apatite (FHA) and hydroxyapatite (HA) particles were obtained using the pH-cyclicing method. After calcination, these FHA particles were homogenized and became single phased FHA. The effect of fluorine content, preparing method, and sintering temperature on both the bulk density and biaxial flexural strength of sintered FHA was studied. Both uniaxially pressed un-milled (UPU) and cold isostatically pressed milled (IPM) FHA discs were sintered at temperatures between 1200˜400°C at an interval of 100°C. It was found that the fluorine content had a significant impact on the sintering behavior, densification, and mechanical properties of FHA discs. A close correlation between the sintered density and biaxial flexural strength of the specimens was revealed, where the biaxial flexural strength increased exponentially with the sintered density. FHA discs with various fluorine contents have been used to investigate the effect of fluorine content on osteoblastic cell behaviors. Rat osteosarcoma (ROS 17/28) cells were cultured on FHA discs for appropriate times. The osteoblastic cell behaviors were examined in terms of cell attachment, proliferation, morphology and differentiation. The fluorine content in FHA strongly affected the cell activities. More cell attachment and proliferation were observed on the fluorine-containing FHA than pure HA. Fluorine content also affected the differentiation behaviors of osteoblastic cells. Cells on fluorine-containing FHA had higher alkaline phosphatase (ALP) activity than pure HA in 2 weeks. The morphology of the cells showed that it took less time for cells to cover the surface of fluorine-containing samples than that of pure HA. These results suggested that fluorine ions had a significant impact on osteoblastic cell behaviors.

Cu toxicity on growth and chlorophyll-a of Chaetoceros sp.

NASA Astrophysics Data System (ADS)

Puspitasari, R.; Suratno; Purbonegoro, T.; Agustin, A. T.

2018-02-01

Phytoplankton is a primary producer in marine aquatic ecosystem. Their sensitivity to metal makes them important to study to predict the environmental impact of pollution. Copper is an essential nutrient for aquatic life as micronutrients on an organism but toxic at high levels. The focus of this study was to assess the toxicity of copper to Chaetoceros sp. on growth and chlorophyll-a content. The result shows that inhibition concentration (IC50) of copper on the microalgae, Chaetoceros sp. was 30.25 μg L-1. Growth of Chaetoceros sp. decreased 16.84% in 16 μg L-1 and 81.97% in 44 μg L-1. Chlorophyll-a content decreased dramatically at 44 μg L-1 compared to control. Increase of the cell size, deformation of cell wall and loss of setae were observed at higher concentration of copper.

Evaluation of the effect of process variables on the fatty acid profile of single cell oil produced by Mortierella using solid-state fermentation.

PubMed

Asadi, Seyedeh Zeinab; Khosravi-Darani, Kianoush; Nikoopour, Houshang; Bakhoda, Hossein

2015-03-01

This article reviews some of the aspects of single cell oil (SCO) production using solid-state fermentation (SSF) by fungi of the genus Mortierella. This article provides an overview of the advantages of SSF for SCO formation by the aforementioned fungus and demonstrates that the content of the polyunsaturated fatty acids (PUFA) depend on the type of fermentation media and culture conditions. Process variables that influence lipid accumulation by Mortierella spp. and the profile of the fatty acids are discussed, including incubation temperature, time, aeration, growth phase of the mycelium, particle size of the substrate, carbon to nitrogen ratio, initial moisture content and pH as well as supplementation of the substrate with nitrogen and oil. Finally, the article highlights future research trends for the scaled-up production of PUFAs in SSF.

Particle size distribution of hydrocyanic acid in gari, a cassava-based product.

PubMed

Maduagwu, E N; Fafunso, M

1980-12-01

A reciprocal relationship was observed between the cyanide content of gari and particle size. Hydrocyanic acid (HCN) content was positively correlated (r = 0.62) with sugar content but the correlation with starch content was poor (r = 0.33). From both the nutritional and toxicological standpoints, it would appear that larger particles size in gari is beneficial.

PtCo Cathode Catalyst Morphological and Compositional Changes after PEM Fuel Cell Accelerated Stress Testing

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

Sneed, Brian T.; Cullen, David A.; Mukundan, R.

Development of Pt catalysts alloyed with transition metals has led to a new class of state-of-the-art electrocatalysts for oxygen reduction at the cathode of proton exchange membrane fuel cells; however, the durability of Pt-based alloy catalysts is challenged by poor structural and chemical stability. There is a need for better understanding of the morphological and compositional changes that occur to the catalyst under fuel cell operation. In this work, we report in-depth characterization results of a Pt-Co electrocatalyst incorporated in the cathode of membrane electrode assemblies, which were evaluated before and after accelerated stress tests designed specifically to enhance catalystmore » degradation. Electron microscopy, spectroscopy, and 3D electron tomography analyses of the Pt-Co nanoparticle structures suggest that the small- and intermediate-sized Pt-Co particles, which are typically Pt-rich in the fresh condition, undergo minimal morphological changes, whereas intermediate- and larger-sized Pt-Co nanoparticles that exhibit a porous “spongy” morphology and initially have a higher Co content, transform into hollowed-out shells, which is driven by continuous leaching of Co from the Pt-Co catalysts. We further show how these primary Pt-Co nanoparticle morphologies group toward a lower Co, larger size portion of the size vs. composition distribution, and provide details of their nanoscale morphological features.« less

PtCo Cathode Catalyst Morphological and Compositional Changes after PEM Fuel Cell Accelerated Stress Testing

DOE PAGES

Sneed, Brian T.; Cullen, David A.; Mukundan, R.; ...

2018-03-01

Development of Pt catalysts alloyed with transition metals has led to a new class of state-of-the-art electrocatalysts for oxygen reduction at the cathode of proton exchange membrane fuel cells; however, the durability of Pt-based alloy catalysts is challenged by poor structural and chemical stability. There is a need for better understanding of the morphological and compositional changes that occur to the catalyst under fuel cell operation. In this work, we report in-depth characterization results of a Pt-Co electrocatalyst incorporated in the cathode of membrane electrode assemblies, which were evaluated before and after accelerated stress tests designed specifically to enhance catalystmore » degradation. Electron microscopy, spectroscopy, and 3D electron tomography analyses of the Pt-Co nanoparticle structures suggest that the small- and intermediate-sized Pt-Co particles, which are typically Pt-rich in the fresh condition, undergo minimal morphological changes, whereas intermediate- and larger-sized Pt-Co nanoparticles that exhibit a porous “spongy” morphology and initially have a higher Co content, transform into hollowed-out shells, which is driven by continuous leaching of Co from the Pt-Co catalysts. We further show how these primary Pt-Co nanoparticle morphologies group toward a lower Co, larger size portion of the size vs. composition distribution, and provide details of their nanoscale morphological features.« less

Bioinformatics analysis of disordered proteins in prokaryotes.

PubMed

Pavlović-Lažetić, Gordana M; Mitić, Nenad S; Kovačević, Jovana J; Obradović, Zoran; Malkov, Saša N; Beljanski, Miloš V

2011-03-02

A significant number of proteins have been shown to be intrinsically disordered, meaning that they lack a fixed 3 D structure or contain regions that do not posses a well defined 3 D structure. It has also been proven that a protein's disorder content is related to its function. We have performed an exhaustive analysis and comparison of the disorder content of proteins from prokaryotic organisms (i.e., superkingdoms Archaea and Bacteria) with respect to functional categories they belong to, i.e., Clusters of Orthologous Groups of proteins (COGs) and groups of COGs-Cellular processes (Cp), Information storage and processing (Isp), Metabolism (Me) and Poorly characterized (Pc). We also analyzed the disorder content of proteins with respect to various genomic, metabolic and ecological characteristics of the organism they belong to. We used correlations and association rule mining in order to identify the most confident associations between specific modalities of the characteristics considered and disorder content. Bacteria are shown to have a somewhat higher level of protein disorder than archaea, except for proteins in the Me functional group. It is demonstrated that the Isp and Cp functional groups in particular (L-repair function and N-cell motility and secretion COGs of proteins in specific) possess the highest disorder content, while Me proteins, in general, posses the lowest. Disorder fractions have been confirmed to have the lowest level for the so-called order-promoting amino acids and the highest level for the so-called disorder promoters. For each pair of organism characteristics, specific modalities are identified with the maximum disorder proteins in the corresponding organisms, e.g., high genome size-high GC content organisms, facultative anaerobic-low GC content organisms, aerobic-high genome size organisms, etc. Maximum disorder in archaea is observed for high GC content-low genome size organisms, high GC content-facultative anaerobic or aquatic or mesophilic organisms, etc. Maximum disorder in bacteria is observed for high GC content-high genome size organisms, high genome size-aerobic organisms, etc. Some of the most reliable association rules mined establish relationships between high GC content and high protein disorder, medium GC content and both medium and low protein disorder, anaerobic organisms and medium protein disorder, Gammaproteobacteria and low protein disorder, etc. A web site Prokaryote Disorder Database has been designed and implemented at the address http://bioinfo.matf.bg.ac.rs/disorder, which contains complete results of the analysis of protein disorder performed for 296 prokaryotic completely sequenced genomes. Exhaustive disorder analysis has been performed by functional classes of proteins, for a larger dataset of prokaryotic organisms than previously done. Results obtained are well correlated to those previously published, with some extension in the range of disorder level and clear distinction between functional classes of proteins. Wide correlation and association analysis between protein disorder and genomic and ecological characteristics has been performed for the first time. The results obtained give insight into multi-relationships among the characteristics and protein disorder. Such analysis provides for better understanding of the evolutionary process and may be useful for taxon determination. The main drawback of the approach is the fact that the disorder considered has been predicted and not experimentally established.

Modeling the competition between antenna size mutant and wild type microalgae in outdoor mass culture.

PubMed

de Mooij, Tim; Schediwy, Kira; Wijffels, René H; Janssen, Marcel

2016-12-20

Under high light conditions, microalgae are oversaturated with light which significantly reduces the light use efficiency. Microalgae with a reduced pigment content, antenna size mutants, have been proposed as a potential solution to increase the light use efficiency. The goal of this study was to investigate the competition between antenna size mutants and wild type microalgae in mass cultures. Using a kinetic model and literature-derived experimental data from wild type Chlorella sorokiniana, the productivity and competition of wild type cells and antenna size mutants were simulated. Cultivation was simulated in an outdoor microalgal raceway pond production system which was assumed to be limited by light only. Light conditions were based on a Mediterranean location (Tunisia) and a more temperate location (the Netherlands). Several wild type contamination levels were simulated in each mutant culture separately to predict the effect on the productivity over the cultivation time of a hypothetical summer season of 100days. The simulations demonstrate a good potential of antenna size reduction to increase the biomass productivity of microalgal cultures. However, it was also found that after a contamination with wild type cells the mutant cultures will be rapidly overgrown resulting in productivity loss. Copyright © 2016 Elsevier B.V. All rights reserved.

Hybrid approach combining multiple characterization techniques and simulations for microstructural analysis of proton exchange membrane fuel cell electrodes

NASA Astrophysics Data System (ADS)

Cetinbas, Firat C.; Ahluwalia, Rajesh K.; Kariuki, Nancy; De Andrade, Vincent; Fongalland, Dash; Smith, Linda; Sharman, Jonathan; Ferreira, Paulo; Rasouli, Somaye; Myers, Deborah J.

2017-03-01

The cost and performance of proton exchange membrane fuel cells strongly depend on the cathode electrode due to usage of expensive platinum (Pt) group metal catalyst and sluggish reaction kinetics. Development of low Pt content high performance cathodes requires comprehensive understanding of the electrode microstructure. In this study, a new approach is presented to characterize the detailed cathode electrode microstructure from nm to μm length scales by combining information from different experimental techniques. In this context, nano-scale X-ray computed tomography (nano-CT) is performed to extract the secondary pore space of the electrode. Transmission electron microscopy (TEM) is employed to determine primary C particle and Pt particle size distributions. X-ray scattering, with its ability to provide size distributions of orders of magnitude more particles than TEM, is used to confirm the TEM-determined size distributions. The number of primary pores that cannot be resolved by nano-CT is approximated using mercury intrusion porosimetry. An algorithm is developed to incorporate all these experimental data in one geometric representation. Upon validation of pore size distribution against gas adsorption and mercury intrusion porosimetry data, reconstructed ionomer size distribution is reported. In addition, transport related characteristics and effective properties are computed by performing simulations on the hybrid microstructure.

Effects of captopril, losartan, and nifedipine on cell hypertrophy of cultured vascular smooth muscle from hypertensive Ren-2 transgenic rats

PubMed Central

Peiró, Concepción; Llergo, José L; Angulo, Javier; López-Novoa, José M; Rodríguez-López, Ana; Rodríguez-Mañas, Leocadio; Sánchez-Ferrer, Carlos F

1997-01-01

We hypothesized that tissular renin-angotensin system (RAS) induces vascular hypertrophy in hypertensive Ren-2 transgenic rats (TGR; strain name TGR(mRen2)L27). This assumption was tested in cell cultures of vascular smooth muscle (VSMC) from both hypertensive TGR and control normotensive Sprague-Dawley (SD) rats. Planar cell surface area, protein synthesis, and protein content per cell were studied, the role for locally produced angiotensin II (AII) was evaluated and the possible pharmacological interference by different drugs was analysed. By use of radioimmunoassay techniques, AII could be determined in TGR cultures (10.25±0.12 pg per 107 cells) while it could not be detected in SD ones. Under serum-free conditions, VSMC from hypertensive TGR were hypertrophic when compared to SD VSMC, as they presented a higher protein content per cell (335±18 and 288±7 pg per cell respectively; P<0.05) and increased mean planar cell surface area, as determined by image analysis (4,074±238 and 4,764±204 μm2, respectively; P<0.05). When exogenously added to cultured SD and TGR VSMC, AII (100 pM to 1 μM) promoted protein synthesis and protein content in a concentration-dependent manner without affecting DNA synthesis. Maximal effects were observed at 100 nM. At this concentration, AII effectively increased planar cell surface area in both SD and TGR cultures by ∼20%. Treatment of TGR cultures, in the absence of exogenous AII, with the angiotensin-converting enzyme inhibitor captopril or the angiotensin AT1 receptors antagonist losartan (100 nM to 10 μM) reduced planar cell surface area in a concentration-dependent manner. In addition, both captopril and losartan (10 μM), decreased protein synthesis by ∼15%. Treatment of SD VSMC, in the absence of exogenous AII, with both captopril and losartan had no effect either on planar cell surface area or protein synthesis. Treatment with the Ca2+ antagonist nifedipine (100 nM to 10 μM) reduced cell size in both SD and TGR cultures. Maximal cell reduction reached by nifedipine averaged 906±58 and 1,292±57 μm2, in SD and TGR, respectively (P<0.05). In addition, nifedipine, nitrendipine and nisoldipine (all at 10 μM) decreased protein synthesis in both cell types by 15–25%. We concluded that cultured VSMC from TGR are hypertrophic in comparison with those from SD. This cell hypertrophy can be the consequence of the expression of the transgene Ren-2 that activates a tissular RAS and locally produces AII, which acts in a paracrine, autocrine, or intracrine manner. Cell hypertrophy in TGR cultures could be selectively reduced by RAS blockade, while nifedipine decreased cell size and protein synthesis in both hypertrophic and non hypertrophic cells. PMID:9257925

Surface free energy predominates in cell adhesion to hydroxyapatite through wettability.

PubMed

Nakamura, Miho; Hori, Naoko; Ando, Hiroshi; Namba, Saki; Toyama, Takeshi; Nishimiya, Nobuyuki; Yamashita, Kimihiro

2016-05-01

The initial adhesion of cells to biomaterials is critical in the regulation of subsequent cell behaviors. The purpose of this study was to investigate a mechanism through which the surface wettability of biomaterials can be improved and determine the effects of biomaterial surface characteristics on cellular behaviors. We investigated the surface characteristics of various types of hydroxyapatite after sintering in different atmospheres and examined the effects of various surface characteristics on cell adhesion to study cell-biomaterial interactions. Sintering atmosphere affects the polarization capacity of hydroxyapatite by changing hydroxide ion content and grain size. Compared with hydroxyapatite sintered in air, hydroxyapatite sintered in saturated water vapor had a higher polarization capacity that increased surface free energy and improved wettability, which in turn accelerated cell adhesion. We determined the optimal conditions of hydroxyapatite polarization for the improvement of surface wettability and acceleration of cell adhesion. Copyright © 2016 Elsevier B.V. All rights reserved.

Relation between clinical mature and immature lymphocyte cells in human peripheral blood and their spatial label free scattering patterns

NASA Astrophysics Data System (ADS)

Zhang, Lu; Zhao, Xin; Zhang, Zhenxi; Zhao, Hong; Chen, Wei; Yuan, Li

2016-07-01

A single living cell's light scattering pattern (LSP) in the horizontal plane, which has been denoted as the cell's "2D fingerprint," may provide a powerful label-free detection tool in clinical applications. We have recently studied the LSP in spatial scattering planes, denoted as the cell's "3D fingerprint," for mature and immature lymphocyte cells in human peripheral blood. The effects of membrane size, morphology, and the existence of the nucleus on the spatial LSP are discussed. In order to distinguish clinical label-free mature and immature lymphocytes, the special features of the spatial LSP are studied by statistical method in both the spatial and frequency domains. Spatial LSP provides rich information on the cell's morphology and contents, which can distinguish mature from immature lymphocyte cells and hence ultimately it may be a useful label-free technique for clinical leukemia diagnosis.

Biological evaluation of ultrananocrystalline and nanocrystalline diamond coatings.

PubMed

Skoog, Shelby A; Kumar, Girish; Zheng, Jiwen; Sumant, Anirudha V; Goering, Peter L; Narayan, Roger J

2016-12-01

Nanostructured biomaterials have been investigated for achieving desirable tissue-material interactions in medical implants. Ultrananocrystalline diamond (UNCD) and nanocrystalline diamond (NCD) coatings are the two most studied classes of synthetic diamond coatings; these materials are grown using chemical vapor deposition and are classified based on their nanostructure, grain size, and sp 3 content. UNCD and NCD are mechanically robust, chemically inert, biocompatible, and wear resistant, making them ideal implant coatings. UNCD and NCD have been recently investigated for ophthalmic, cardiovascular, dental, and orthopaedic device applications. The aim of this study was (a) to evaluate the in vitro biocompatibility of UNCD and NCD coatings and (b) to determine if variations in surface topography and sp 3 content affect cellular response. Diamond coatings with various nanoscale topographies (grain sizes 5-400 nm) were deposited on silicon substrates using microwave plasma chemical vapor deposition. Scanning electron microscopy and atomic force microscopy revealed uniform coatings with different scales of surface topography; Raman spectroscopy confirmed the presence of carbon bonding typical of diamond coatings. Cell viability, proliferation, and morphology responses of human bone marrow-derived mesenchymal stem cells (hBMSCs) to UNCD and NCD surfaces were evaluated. The hBMSCs on UNCD and NCD coatings exhibited similar cell viability, proliferation, and morphology as those on the control material, tissue culture polystyrene. No significant differences in cellular response were observed on UNCD and NCD coatings with different nanoscale topographies. Our data shows that both UNCD and NCD coatings demonstrate in vitro biocompatibility irrespective of surface topography.

Hydrophysical correlation and water mass indication of optical physiological parameters of picophytoplankton in Prydz Bay during autumn 2008.

PubMed

Zhang, Fang; Ma, Yuxin; Lin, Ling; He, Jianfeng

2012-12-01

Flow cytometry (FCM) is efficient in detecting both abundance and optical physiological parameters including cell size and cellular carbon content-side scatter (SSC), carotenoids-green and orange fluorescence (FL1 and FL2), and red fluorescence-chlorophylls (FL3) can be obtained by FCM. The utilization of these physiological parameters in indicating water masses in Prydz Bay was investigated for the first time. Picophytoplankton were very sensitive to hydrophysical changes and present distinct characteristics of water masses: Picophytoplankton in water closer to the Amery Ice Shelf were more affected by salinity than by temperature, while temperature became more important than salinity the nearer the picophytoplankton were to the deep sea. The picophytoplankton dealt with declines in light by increasing the size of cells, which increase the fixation of carbon. This can also be increased by high temperature and salinity. Pure water masses can increase the content of chlorophylls and cellular carbon. Generally, the distributions of all the five parameters at upper water depths were less affected by temperature and salinity than by water masses; and these parameters can be as indicators to Summer Surface Water (SSW), Winter Water (WW) and Continental Shelf Water (CSW). Copyright © 2012 Elsevier B.V. All rights reserved.

Carrying photosynthesis genes increases ecological fitness of cyanophage in silico.

PubMed

Hellweger, Ferdi L

2009-06-01

Several viruses infecting marine cyanobacteria carry photosynthesis genes (e.g. psbA, hli) that are expressed, yield proteins (D1, HLIP) and help maintain the cell's photosynthesis apparatus during the latent period. This increases energy and speeds up virus production, allowing for a reduced latent period (a fitness benefit), but it also increases the DNA size, which slows down new virus production and reduces burst size (a fitness cost). How do these genes affect the net ecological fitness of the virus? Here, this question is explored using a combined systems biology and systems ecology ('systems bioecology') approach. A novel agent-based model simulates individual cyanobacteria cells and virus particles, each with their own genes, transcripts, proteins and other properties. The effect of D1 and HLIP proteins is explicitly considered using a mechanistic photosynthesis component. The model is calibrated to the available database for Prochlorococcus ecotype MED4 and podovirus P-SSP7. Laboratory- and field-scale in silico survival, competition and evolution (gene packaging error) experiments with wild type and genetically engineered viruses are performed to develop vertical survival and fitness profiles, and to determine the optimal gene content. The results suggest that photosynthesis genes are nonessential, increase fitness in a manner correlated with irradiance, and that the wild type has an optimal gene content.

Tumour budding activity and cell nest size determine patient outcome in oral squamous cell carcinoma: proposal for an adjusted grading system.

PubMed

Boxberg, Melanie; Jesinghaus, Moritz; Dorfner, Christiane; Mogler, Carolin; Drecoll, Enken; Warth, Arne; Steiger, Katja; Bollwein, Christine; Meyer, Petra; Wolff, Klaus D; Kolk, Andreas; Weichert, Wilko

2017-06-01

Oral squamous cell carcinoma (OSCC) is a common malignancy with a variable clinical course. One of the established survival predictors in carcinomas in general is tumour grade; in OSCC, however, grading according to the World Health Organization (WHO) has no independent prognostic impact. Recently, a novel grading scheme associated with high impact on patient outcome has been proposed for squamous cell carcinoma of the lung. To probe whether this scheme could be applied to the upper aerodigestive tract, we retrospectively evaluated 157 chemo- and radiotherapy-naive OSCCs with complete clinical follow-up data and standardized treatment for tumour budding activity (BA), cell nest size (CNS), extent of keratinization, stromal content, nuclear size and mitotic count. Histomorphological characteristics were correlated with clinicopathological data and patient outcome. As in squamous cell carcinoma of the lung, high BA and small CNS were correlated significantly with shortened overall, disease-specific and disease-free survival. A three-tiered grading system based on a sum score of these two prognostic markers proved to be a strong age-, stage- and sex-independent prognosticator for survival with a hazard ratio for overall survival of 2.1 for intermediately differentiated (G2) tumours and 3.4 for poorly differentiated (G3) tumours compared to well-differentiated (G1) tumours (P < 0.001). We recapitulated and validated almost exactly the strong prognostic impact of a grading algorithm proposed recently for squamous cell carcinoma of the lung in OSCC. Our data may pave the way for a prognostically highly relevant future squamous cell carcinoma grading system broadly applicable in the aerodigestive tract. © 2017 John Wiley & Sons Ltd.

The Effect of Crumb Rubber Particle Size to the Optimum Binder Content for Open Graded Friction Course

PubMed Central

Ibrahim, Mohd Rasdan; Katman, Herda Yati; Karim, Mohamed Rehan; Koting, Suhana; Mashaan, Nuha S.

2014-01-01

The main objective of this paper is to investigate the relations of rubber size, rubber content, and binder content in determination of optimum binder content for open graded friction course (OGFC). Mix gradation type B as specified in Specification for Porous Asphalt produced by the Road Engineering Association of Malaysia (REAM) was used in this study. Marshall specimens were prepared with four different sizes of rubber, namely, 20 mesh size [0.841 mm], 40 mesh [0.42 mm], 80 mesh [0.177 mm], and 100 mesh [0.149 mm] with different concentrations of rubberised bitumen (4%, 8%, and 12%) and different percentages of binder content (4%–7%). The appropriate optimum binder content is then selected according to the results of the air voids, binder draindown, and abrasion loss test. Test results found that crumb rubber particle size can affect the optimum binder content for OGFC. PMID:24574875

Organic and Inorganic Nitrogen Impact Chlorella variabilis Productivity and Host Quality for Viral Production and Cell Lysis.

PubMed

Cheng, Yu-Shen; Labavitch, John; VanderGheynst, Jean S

2015-05-01

Microalgae have been proposed as a potential feedstock for biofuel production; however, cell disruption is usually required for collection and utilization of cytoplasmic polysaccharides and lipids. Virus infection might be one approach to disrupt the cell wall. The concentration of yeast extract and presence of KNO3 in algae cultivation media were investigated to observe their effects on Chlorella variabilis NC64A physiology and composition and the subsequent effect on production of Chlorella virus and disruption of infected cells. Cytoplasmic starch accumulation increased from 5% to approximately 35% of the total dry weight when yeast extract decreased from 1 to 0.25 g L(-1). When cells were cultured with the lowest nitrogen levels, the total polysaccharide accounted for more than 50% of the cell wall, which was 1.7 times higher than the content in cells cultured with the highest nitrogen levels. The C/N ratio of the algal biomass decreased by a factor of approximately 2 when yeast extract increased from 0.25 to 1 g L(-1). After virus infection, cells with a low C/N ratio produced a 7.6 times higher burst size than cells with a high C/N ratio, suggesting that the nitrogen content in C. variabilis has a large influence on viral production and cell lysis. The results have implications on management of nitrogen for both the synthesis of products from algae and product recovery via viral lysis.

Using flow cytometry to estimate pollen DNA content: improved methodology and applications

PubMed Central

Kron, Paul; Husband, Brian C.

2012-01-01

Background and Aims Flow cytometry has been used to measure nuclear DNA content in pollen, mostly to understand pollen development and detect unreduced gametes. Published data have not always met the high-quality standards required for some applications, in part due to difficulties inherent in the extraction of nuclei. Here we describe a simple and relatively novel method for extracting pollen nuclei, involving the bursting of pollen through a nylon mesh, compare it with other methods and demonstrate its broad applicability and utility. Methods The method was tested across 80 species, 64 genera and 33 families, and the data were evaluated using established criteria for estimating genome size and analysing cell cycle. Filter bursting was directly compared with chopping in five species, yields were compared with published values for sonicated samples, and the method was applied by comparing genome size estimates for leaf and pollen nuclei in six species. Key Results Data quality met generally applied standards for estimating genome size in 81 % of species and the higher best practice standards for cell cycle analysis in 51 %. In 41 % of species we met the most stringent criterion of screening 10 000 pollen grains per sample. In direct comparison with two chopping techniques, our method produced better quality histograms with consistently higher nuclei yields, and yields were higher than previously published results for sonication. In three binucleate and three trinucleate species we found that pollen-based genome size estimates differed from leaf tissue estimates by 1·5 % or less when 1C pollen nuclei were used, while estimates from 2C generative nuclei differed from leaf estimates by up to 2·5 %. Conclusions The high success rate, ease of use and wide applicability of the filter bursting method show that this method can facilitate the use of pollen for estimating genome size and dramatically improve unreduced pollen production estimation with flow cytometry. PMID:22875815

Nuclear DNA Content Variation in Life History Phases of the Bonnemasoniaceae (Rhodophyta)

PubMed Central

Salvador Soler, Noemi; Gómez Garreta, Amelia; Ribera Siguan, Mª Antonia; Kapraun, Donald F.

2014-01-01

Nuclear DNA content in gametophytes and sporophytes or the prostrate phases of the following species of Bonnemaisoniaceae (Asparagopsis armata, Asparagopsis taxiformis, Bonnemaisonia asparagoides, Bonnemaisonia clavata and Bonnemaisonia hamifera) were estimated by image analysis and static microspectrophotometry using the DNA-localizing fluorochrome DAPI (4′, 6-diamidino-2-phenylindole, dilactate) and the chicken erythrocytes standard. These estimates expand on the Kew database of DNA nuclear content. DNA content values for 1C nuclei in the gametophytes (spermatia and vegetative cells) range from 0.5 pg to 0.8 pg, and for 2C nuclei in the sporophytes or the prostrate phases range from 1.15–1.7 pg. Although only the 2C and 4C values were observed in the sporophyte or the prostrate phase, in the vegetative cells of the gametophyte the values oscillated from 1C to 4C, showing the possible start of endopolyploidy. The results confirm the alternation of nuclear phases in these Bonnemaisoniaceae species, in those that have tetrasporogenesis, as well as those that have somatic meiosis. The availability of a consensus phylogenetic tree for Bonnemaisoniaceae has opened the way to determine evolutionary trends in DNA contents. Both the estimated genome sizes and the published chromosome numbers for Bonnemaisoniaceae suggest a narrow range of values consistent with the conservation of an ancestral genome. PMID:24465835

EGY1 plays a role in regulation of endodermal plastid size and number that are involved in ethylene-dependent gravitropism of light-grown Arabidopsis hypocotyls.

PubMed

Guo, Di; Gao, Xiaorong; Li, Hao; Zhang, Tao; Chen, Gu; Huang, Pingbo; An, Lijia; Li, Ning

2008-03-01

Egy1 was isolated as an ethylene-dependent gravitropism-deficient Arabidopsis mutant. Molecular studies reveal that EGY1 gene encodes a 59-kDa plastid-targeted metalloprotease. It is actively expressed in hypocotyl tissue and targets to endodermal and cortex plastid. Its protein level is up-regulated by both ethylene and light. CAB protein accumulation and chlorophyll level is severely reduced in hypocotyls and endodermal cells, respectively. Sucrose is able to restore the severely reduced starch and lipid contents as well as the deficient endodermal plastid size found in light-grown egy1 hypocotyls yet it fails to rescue the reduced plastid number and chlorophyll level in egy1 endodermal cells. The loss-of-function egy1 mutation results in a smaller size (1.9 +/- 0.3 microm in diameter) and less number (5 +/- 1) of plastids in endodermal cells, which are nearly 50% of the wild-type. EGY1 is specially required for the development of full-size endodermal plastid in seedlings that are grown on sucrose-free media under light. It plays a direct role in controlling the light-induced chlorophyll production, grana formation and plastid replication in endodermal cell. However, it plays an indirect role in regulation of endodermal plastid size. It is likely that the ethylene-dependent gravitropism-deficient phenotype of egy1 hypocotyls may result from the smaller size and less number of endodermal plastids. Gravicurvature assays performed on ethylene-insensitive mutants, etr1-1, etr2-1, ers2-1, ein4-1 and ein2-5, have clearly demonstrated the necessary role for ethylene in vigorous gravitropism of light-grown hypocotyls. The degree of ethylene-dependent gravicurvature is positively correlated with the combined state of endodermal plastid mass and number. Neither ethylene nor EGY1-regulated full-size endodermal plastid is sufficient for promotion of vigorous hypocotyl gravitropism. Presence of 4 full-size plastids per endodermal cell together with ethylene pretreatment of hypocotyls becomes sufficient to trigger vigorous gravicurvature in light-grown seedlings. A model is therefore proposed to address the role of EGY1 in regulation of endodermal plastid size and number as well as the stimulatory effect of ethylene on hypocotyl gravitropism.

Experimentally Induced Repeated Anhydrobiosis in the Eutardigrade Richtersius coronifer.

PubMed

Czernekova, Michaela; Jönsson, K Ingemar

2016-01-01

Tardigrades represent one of the main animal groups with anhydrobiotic capacity at any stage of their life cycle. The ability of tardigrades to survive repeated cycles of anhydrobiosis has rarely been studied but is of interest to understand the factors constraining anhydrobiotic survival. The main objective of this study was to investigate the patterns of survival of the eutardigrade Richtersius coronifer under repeated cycles of desiccation, and the potential effect of repeated desiccation on size, shape and number of storage cells. We also analyzed potential change in body size, gut content and frequency of mitotic storage cells. Specimens were kept under non-cultured conditions and desiccated under controlled relative humidity. After each desiccation cycle 10 specimens were selected for analysis of morphometric characteristics and mitosis. The study demonstrates that tardigrades may survive up to 6 repeated desiccations, with declining survival rates with increased number of desiccations. We found a significantly higher proportion of animals that were unable to contract properly into a tun stage during the desiccation process at the 5th and 6th desiccations. Also total number of storage cells declined at the 5th and 6th desiccations, while no effect on storage cell size was observed. The frequency of mitotic storage cells tended to decline with higher number of desiccation cycles. Our study shows that the number of consecutive cycles of anhydrobiosis that R. coronifer may undergo is limited, with increased inability for tun formation and energetic constraints as possible causal factors.

Experimentally Induced Repeated Anhydrobiosis in the Eutardigrade Richtersius coronifer

PubMed Central

2016-01-01

Tardigrades represent one of the main animal groups with anhydrobiotic capacity at any stage of their life cycle. The ability of tardigrades to survive repeated cycles of anhydrobiosis has rarely been studied but is of interest to understand the factors constraining anhydrobiotic survival. The main objective of this study was to investigate the patterns of survival of the eutardigrade Richtersius coronifer under repeated cycles of desiccation, and the potential effect of repeated desiccation on size, shape and number of storage cells. We also analyzed potential change in body size, gut content and frequency of mitotic storage cells. Specimens were kept under non-cultured conditions and desiccated under controlled relative humidity. After each desiccation cycle 10 specimens were selected for analysis of morphometric characteristics and mitosis. The study demonstrates that tardigrades may survive up to 6 repeated desiccations, with declining survival rates with increased number of desiccations. We found a significantly higher proportion of animals that were unable to contract properly into a tun stage during the desiccation process at the 5th and 6th desiccations. Also total number of storage cells declined at the 5th and 6th desiccations, while no effect on storage cell size was observed. The frequency of mitotic storage cells tended to decline with higher number of desiccation cycles. Our study shows that the number of consecutive cycles of anhydrobiosis that R. coronifer may undergo is limited, with increased inability for tun formation and energetic constraints as possible causal factors. PMID:27828978

Magnetite nanoparticles functionalized with α-tocopheryl succinate (α-TOS) promote selective cervical cancer cell death

NASA Astrophysics Data System (ADS)

Angulo-Molina, Aracely; Méndez-Rojas, Miguel Ángel; Palacios-Hernández, Teresa; Contreras-López, Oscar Edel; Hirata-Flores, Gustavo Alonso; Flores-Alonso, Juan Carlos; Merino-Contreras, Saul; Valenzuela, Olivia; Hernández, Jesús; Reyes-Leyva, Julio

2014-08-01

The vitamin E analog α-tocopheryl succinate (α-TOS) selectively induces apoptosis in several cancer cells, but it is sensitive to esterases present in cervical cancer cells. Magnetite nanoparticles (Nps) were prepared by a reduction-coprecipitation method; their surface was silanized and conjugated to α-TOS to enhance its resistance. Morphology, size, and crystal structure were analyzed by scanning electron microscopy, transmission electron microscopy, and selected area electron diffraction. Chemical composition was analyzed by energy-dispersive X-ray spectroscopy; functional groups were determined by Fourier transform infrared spectroscopy; and α-TOS content was estimated by thermogravimetric analysis. The cytotoxic activity of α-TOS-Nps was evaluated in non-malignant fibroblasts and cervical cancer cells by means of the colorimetric MTT viability test. Intracellular localization was identified by confocal laser scanning microscopy. Characterization of α-TOS-Nps revealed sphere-like Nps with 15 nm average size, formed by mineral and organic constituents with high stability. α-TOS-Nps were internalized in the nucleus and selectively affected the viability of cervical cancer cells in a dose- and time-dependent manner but were biocompatible with non-malignant fibroblasts. In conclusion, functionalization of magnetite Nps protected the cytotoxic activity of α-TOS in non-sensitive cervical cancer cells.

[Intercellular relationship of notochord determination of Xenopus laevis].

PubMed

Zeng, M B; Zhou, M Y; Wang, Y

1995-09-01

During the process of determination, the presumptive notochord is situated beneath neuroepithelium, flanked at two sides by presumptive somites and underlain with archenteron roof ventrally. Among these neighbouring embryonic tissues, presumptive somites were found to exert the main influence on notochord determination. By electron microscopic observations, the presumptive notochord and somite cells were seen to situate either close to each other (plate I, Fig. 1) or connected by cytoplasmic processes forming intercellular lumen (plate I, Fig. 5). Coated pits and coated vesicles appeared at the outer surface of both types of cells (plate I, Figs. 1-4). For the presumptive somite cells, spherical bodies of different sizes and variable contents were observed either near or protruding from the outer surface (plate II, Figs. 6-10). The spherical bodies were also found in the intercellular lumen (plate III, Fig. 11). These spherical bodies were mainly composed of granules, loosely scattered or densely packed. The granules were of similar size and similar shade of electron staining as those of ribosomes of the presumptive somite cells. For the presumptive notochord cells, no spherical bodies of the above mentioned type were found, but phenomenon of engulfing luminal material was observed (plate III, Fig. 12). The significance of the appearance of these spherical bodies in the determination of notochord cells has been discussed.

Characterization of cement float buoyancy in the stalked barnacle Dosima fascicularis (Crustacea, Cirripedia).

PubMed

Zheden, Vanessa; Kovalev, Alexander; Gorb, Stanislav N; Klepal, Waltraud

2015-02-06

Dosima fascicularis is the only barnacle which can drift autonomously at the water surface with a foam-like cement float. The cement secreted by the animal contains numerous gas-filled cells of different size. When several individuals share one float, their size and not their number is crucial for the production of both volume and mass of the float. The gas content within the cells of the foam gives positive static buoyancy to the whole float. The volume of the float, the gas volume and the positive static buoyancy are positively correlated. The density of the cement float without gas is greater than that of seawater. This study shows that the secreted cement consists of more than 90% water and the gas volume is on average 18.5%. Our experiments demonstrate that the intact foam-like cement float is sealed to the surrounding water.

Characterization of cement float buoyancy in the stalked barnacle Dosima fascicularis (Crustacea, Cirripedia)

PubMed Central

Zheden, Vanessa; Kovalev, Alexander; Gorb, Stanislav N.; Klepal, Waltraud

2015-01-01

Dosima fascicularis is the only barnacle which can drift autonomously at the water surface with a foam-like cement float. The cement secreted by the animal contains numerous gas-filled cells of different size. When several individuals share one float, their size and not their number is crucial for the production of both volume and mass of the float. The gas content within the cells of the foam gives positive static buoyancy to the whole float. The volume of the float, the gas volume and the positive static buoyancy are positively correlated. The density of the cement float without gas is greater than that of seawater. This study shows that the secreted cement consists of more than 90% water and the gas volume is on average 18.5%. Our experiments demonstrate that the intact foam-like cement float is sealed to the surrounding water. PMID:25657839

The impact of image-size manipulation and sugar content on children's cereal consumption.

PubMed

Neyens, E; Aerts, G; Smits, T

2015-12-01

Previous studies have demonstrated that portion sizes and food energy-density influence children's eating behavior. However, the potential effects of front-of-pack image-sizes of serving suggestions and sugar content have not been tested. Using a mixed experimental design among young children, this study examines the effects of image-size manipulation and sugar content on cereal and milk consumption. Children poured and consumed significantly more cereal and drank significantly more milk when exposed to a larger sized image of serving suggestion as compared to a smaller image-size. Sugar content showed no main effects. Nevertheless, cereal consumption only differed significantly between small and large image-sizes when sugar content was low. An advantage of this study was the mundane setting in which the data were collected: a school's dining room instead of an artificial lab. Future studies should include a control condition, with children eating by themselves to reflect an even more natural context. Copyright © 2015 Elsevier Ltd. All rights reserved.

Electrolyte management considerations in modern nickel hydrogen and nickel cadmium cell and battery designs

NASA Technical Reports Server (NTRS)

Thaller, L. H.; Zimmerman, A. H.

1995-01-01

In the early 1980's the NASA Lewis group addressed the topic of designing nickel hydrogen cells for LEO applications. As published in 1984, the design addressed the topics of gas management, liquid management, plate expansion, and the recombination of oxygen during overcharge. This design effort followed principles set forth in an earlier Lewis paper that addressed the topic of pore size engineering. At about that same time, the beneficial effect on cycle life of lower electrolyte concentrations was verified by Hughes Aircraft as part of a Lewis funded study. A succession of life cycle tests of these concepts have been carried out that essentially verified all of this earlier work. During these past two decades, some of the mysteries involved in the active material of the nickel electrode have been resolved by careful research efforts carried out at several laboratories. At The Aerospace Corporation, Dr. Zimmerman has been developing a sophisticated model of an operating nickel hydrogen cell which will be used to model certain mechanisms that have contributed to premature failures in nickel hydrogen and nickel cadmium cells. During the course of trying to understand and model abnormal nickel hydrogen cell behaviors, we have noted that not enough attention has been paid to the potassium ion content in these cells, and more recently batteries. Several of these phenomenon have been well known in the area of alkaline fuel cells, but only recently have they been examined as they might impact alkaline cell designs. This paper will review three general areas where the potassium ion content can impact the performance and life of nickel hydrogen and nickel cadmium devices, Once these phenomenon are understood conceptually, the impact of potassium content on a potential cell design can be evaluated with the aid of an accurate model of an operating cell or battery. All three of these areas are directly related to the volume tolerance and pore size engineering aspects of the components used in the cell or battery design: (1) The gamma phase uptake of potassium ion can result in a lowering of the electrolyte concentration. This leads to a higher electrolyte resistance as well as electrolyte diffusional limitations on the discharge rate. This phenomenon will also impact the response of the cell to a reconditioning cycle. (2) The impact of low level shunt currents in multi-cell con figurations will result in the movement of potassium ion from one part of the battery to another. This will impact the electrolyte volume/vapor pressure relationships within the cell or battery. (3) The transport of water vapor from place to place under the driving force of a tempetature gradient has already impacted cells for the case where water vapor is condensed on a colder cell wall. The paper will explore the convective and diffusive movement of gases saturated with water vapor from a warmer plate pack to a cooler one - both with and without liquid communication.

Measurement of variation in soil solute tracer concentration across a range of effective pore sizes

USGS Publications Warehouse

Harvey, Judson W.

1993-01-01

Solute transport concepts in soil are based on speculation that solutes are distributed nonuniformly within large and small pores. Solute concentrations have not previously been measured across a range of pore sizes and examined in relation to soil hydrological properties. For this study, modified pressure cells were used to measure variation in concentration of a solute tracer across a range of pore sizes. Intact cores were removed from the site of a field tracer experiment, and soil water was eluted from 10 or more discrete classes of pore size. Simultaneous changes in water content and unsaturated hydraulic conductivity were determined on cores using standard pressure cell techniques. Bromide tracer concentration varied by as much as 100% across the range of pore sizes sampled. Immediately following application of the bromide tracer on field plots, bromide was most concentrated in the largest pores; concentrations were lower in pores of progressively smaller sizes. After 27 days, bromide was most dilute in the largest pores and concentrations were higher in the smaller pores. A sharp, threefold decrease in specific water capacity during elution indicated separation of two major pore size classes at a pressure of 47 cm H2O and a corresponding effective pore diameter of 70 μm. Variation in tracer concentration, on the other hand, was spread across the entire range of pore sizes investigated in this study. A two-porosity characterization of the transport domain, based on water retention criteria, only broadly characterized the pattern of variation in tracer concentration across pore size classes during transport through a macroporous soil.

Frequency and field dependent dynamic properties of CoFe{sub 2−x}Al{sub x}O{sub 4} ferrite nanoparticles

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

Kuanr, Bijoy K.; Department of Physics, University of Colorado, 1420 Austin Bluffs Parkway, Colorado Springs, CO 80918; Mishra, S.R., E-mail: srmishra@memphis.edu

2016-04-15

Highlights: “CoFe{sub 2−x} Al{sub x}O{sub 4} ferrite nanoparticles: Static and dynamic properties” • Grain size reduction with Al{sup 3+} content. • Reduction in Ms, Hc, with increasing Al{sup 3+} content. • Increase in resonance frequency with applied field. • Decrease in resonance field with increase in Al{sup 3+} content. • Decrease in Gilbert parameter with increase in Al{sup 3+} content. - Abstract: Aluminum doped CoFe{sub 2−x}Al{sub x}O{sub 4} (0 ≤ x ≤ 0.9) nanoparticles were synthesized via auto-combustion. Formation of single phase cubic spinel structure was confirmed by X-ray diffraction (XRD) analysis. XRD analysis suggests a linear decrease in latticemore » cell parameters and grain size (90–55 nm) with the increase in Al{sup 3+} content. The saturation magnetization of samples decrease with increasing Al{sup 3+} content due to magnetic dilution effect. A concomitant linear reduction in coercivity was also observed mainly due to decrease in magnetic anisotropy. Frequency and field dependent dynamic properties of nanoparticles were studied by ferromagnetic resonance (FMR) technique. The resonance frequency increases linearly with magnetic field for all nanoparticles. Magnetic field dependent experimental absorption data (S{sub 21} vs. frequency) were compared with effective medium theory considering an effective demagnetization field and was observed to be in good agreement with each other. High Al{sup 3+} content reduces the Gilbert damping parameter thus making CoFe{sub 2−x}Al{sub x}O{sub 4} as an attractive material for high frequency applications.« less

Impact of lysosome status on extracellular vesicle content and release.

PubMed

Eitan, Erez; Suire, Caitlin; Zhang, Shi; Mattson, Mark P

2016-12-01

Extracellular vesicles (EVs) are nanoscale size bubble-like membranous structures released from cells. EVs contain RNA, lipids and proteins and are thought to serve various roles including intercellular communication and removal of misfolded proteins. The secretion of misfolded and aggregated proteins in EVs may be a cargo disposal alternative to the autophagy-lysosomal and ubiquitin-proteasome pathways. In this review we will discuss the importance of lysosome functionality for the regulation of EV secretion and content. Exosomes are a subtype of EVs that are released by the fusion of multivesicular bodies (MVB) with the plasma membrane. MVBs can also fuse with lysosomes, and the trafficking pathway of MVBs can therefore determine whether or not exosomes are released from cells. Here we summarize data from studies of the effects of lysosome inhibition on the secretion of EVs and on the possibility that cells compensate for lysosome malfunction by disposal of potentially toxic cargos in EVs. A better understanding of the molecular mechanisms that regulate trafficking of MVBs to lysosomes and the plasma membrane may advance an understanding of diseases in which pathogenic proteins, lipids or infectious agents accumulate within or outside of cells. Copyright © 2016. Published by Elsevier B.V.

Impact of Lysosome Status on Extracellular Vesicle Content and Release

PubMed Central

Eitan, Erez; Suire, Caitlin; Zhang, Shi; Mattson, Mark P.

2016-01-01

Extracellular vesicles (EVs) are nanoscale size bubble-like membranous structures released from cells. EVs contain RNA, lipids and proteins and are thought to serve various roles including intercellular communication and removal of misfolded proteins. The secretion of misfolded and aggregated proteins in EVs may be a cargo disposal alternative to the autophagy-lysosomal and ubiquitin-proteasome pathways. In this review we will discuss the importance of lysosome functionality for the regulation of EV secretion and content. Exosomes are a subtype of EVs that are released by the fusion of multivesicular bodies (MVB) with the plasma membrane. MVBs can also fuse with lysosomes, and the trafficking pathway of MVBs can therefore determine whether or not exosomes are released from cells. Here we summarize data from studies of the effects of lysosome inhibition on the secretion of EVs and on the possibility that cells compensate for lysosome malfunction by disposal of potentially toxic cargos in EVs. A better understanding of the molecular mechanisms that regulate trafficking of MVBs to lysosomes and the plasma membrane may advance an understanding of diseases in which pathogenic proteins, lipids or infectious agents accumulate within or outside of cells. PMID:27238186

Recycled de-Oiled Algal Biomass Extract as a Feedstock for Boosting Biodiesel Production from Chlorella minutissima.

PubMed

Arora, Neha; Patel, Alok; Pruthi, Parul A; Pruthi, Vikas

2016-12-01

The investigation for the first time assesses the efficacy of recycled de-oiled algal biomass extract (DABE) as a cultivation media to boost lipid productivity in Chlorella minutissima and its comparison with Bold's basal media (BBM) used as control. Presence of organic carbon (3.8 ± 0.8 g/l) in recycled DABE resulted in rapid growth with twofold increase in biomass productivity as compared to BBM. These cells expressed four folds higher lipid productivity (126 ± 5.54 mg/l/d) as compared to BBM. Cells cultivated in recycled DABE showed large sized lipid droplets accumulating 54.12 % of lipid content. Decrement in carbohydrate (17.76 %) and protein content (28.12 %) with loss of photosynthetic pigments compared to BBM grown cells were also recorded. The fatty acid profiles of cells cultivated in recycled DABE revealed the dominance of C16:0 (39.66 %), C18:1 (29.41 %) and C18:0 (15.82 %), respectively. This model is self-sustained and aims at neutralizing excessive feedstock consumption by exploiting recycled de-oiled algal biomass for cultivation of microalgae, making the process cost effective.

Characterization of mechanical and biological properties of 3-D scaffolds reinforced with zinc oxide for bone tissue engineering.

PubMed

Feng, Pei; Wei, Pingpin; Shuai, Cijun; Peng, Shuping

2014-01-01

A scaffold for bone tissue engineering should have highly interconnected porous structure, appropriate mechanical and biological properties. In this work, we fabricated well-interconnected porous β-tricalcium phosphate (β-TCP) scaffolds via selective laser sintering (SLS). We found that the mechanical and biological properties of the scaffolds were improved by doping of zinc oxide (ZnO). Our data showed that the fracture toughness increased from 1.09 to 1.40 MPam(1/2), and the compressive strength increased from 3.01 to 17.89 MPa when the content of ZnO increased from 0 to 2.5 wt%. It is hypothesized that the increase of ZnO would lead to a reduction in grain size and an increase in density of the strut. However, the fracture toughness and compressive strength decreased with further increasing of ZnO content, which may be due to the sharp increase in grain size. The biocompatibility of the scaffolds was investigated by analyzing the adhesion and the morphology of human osteoblast-like MG-63 cells cultured on the surfaces of the scaffolds. The scaffolds exhibited better and better ability to support cell attachment and proliferation when the content of ZnO increased from 0 to 2.5 wt%. Moreover, a bone like apatite layer formed on the surfaces of the scaffolds after incubation in simulated body fluid (SBF), indicating an ability of osteoinduction and osteoconduction. In summary, interconnected porous β-TCP scaffolds doped with ZnO were successfully fabricated and revealed good mechanical and biological properties, which may be used for bone repair and replacement potentially.

Simultaneous cathodoluminescence and electron microscopy cytometry of cellular vesicles labeled with fluorescent nanodiamonds.

PubMed

Nagarajan, Sounderya; Pioche-Durieu, Catherine; Tizei, Luiz H G; Fang, Chia-Yi; Bertrand, Jean-Rémi; Le Cam, Eric; Chang, Huan-Cheng; Treussart, François; Kociak, Mathieu

2016-06-02

Light and Transmission Electron Microscopies (LM and TEM) hold potential in bioimaging owing to the advantages of fast imaging of multiple cells with LM and ultrastructure resolution offered by TEM. Integrated or correlated LM and TEM are the current approaches to combine the advantages of both techniques. Here we propose an alternative in which the electron beam of a scanning TEM (STEM) is used to excite concomitantly the luminescence of nanoparticle labels (a process known as cathodoluminescence, CL), and image the cell ultrastructure. This CL-STEM imaging allows obtaining luminescence spectra and imaging ultrastructure simultaneously. We present a proof of principle experiment, showing the potential of this technique in image cytometry of cell vesicular components. To label the vesicles we used fluorescent diamond nanocrystals (nanodiamonds, NDs) of size ≈150 nm coated with different cationic polymers, known to trigger different internalization pathways. Each polymer was associated with a type of ND with a different emission spectrum. With CL-STEM, for each individual vesicle, we were able to measure (i) their size with nanometric resolution, (ii) their content in different ND labels, and realize intracellular component cytometry. In contrast to the recently reported organelle flow cytometry technique that requires cell sonication, CL-STEM-based image cytometry preserves the cell integrity and provides a much higher resolution in size. Although this novel approach is still limited by a low throughput, the automatization of data acquisition and image analysis, combined with improved intracellular targeting, should facilitate applications in cell biology at the subcellular level.

Root graviresponsiveness and columella cell structure in carotenoid-deficient seedlings of Zea mays

NASA Technical Reports Server (NTRS)

Moore, R.; McClelen, C. E.

1985-01-01

Root graviresponsiveness in normal and carotenoid-deficient mutant seedlings of Zea mays was not significantly different. Columella cells in roots of mutant seedlings were characterized by fewer, smaller, and a reduced relative volume of plastids as compared to columella cells of normal seedlings. Plastids in columella cells of mutant seedlings possessed reduced amounts of starch. Although approximately 10 per cent of the columella cells in mutant seedlings lacked starch, their plastids were located at the bottom of the cell. These results suggest that (i) carotenoids are not necessary for root gravitropism, (ii) graviresponsiveness is not necessarily proportional to the size, number, or relative volume of plastids in columella cells, and (iii) sedimentation of plastids in columella cells may not result directly from their increased density due to starch content. Plastids in columella cells of normal and mutant seedlings were associated with bands of microtubule-like structures, suggesting that these structures may be involved in 'positioning' plastids in the cell.

Influence of key processing parameters and seeding density effects of microencapsulated chondrocytes fabricated using electrohydrodynamic spraying.

PubMed

Gansau, Jennifer; Kelly, Lara; Buckley, Conor

2018-06-11

Cell delivery and leakage during injection remains a challenge for cell-based intervertebral disc regeneration strategies. Cellular microencapsulation may offer a promising approach to overcome these limitations by providing a protective niche during intradiscal injection. Electrohydrodynamic spraying (EHDS) is a versatile one-step approach for microencapsulation of cells using a high voltage electric field. The primary objective of this work was to characterise key processing parameters such as applied voltage (0, 5, 10 or 15kV), emitter needle gauge (21, 26 or 30G), alginate concentration (1, 2 or 3%) and flow rate (50, 100, 250 or 500 µl/min) to regulate the morphology of alginate microcapsules and subsequent cell viability when altering these parameters. The effect of initial cell seeding density (5, 10 and 20x10⁶ cells/ml) on subsequent matrix accumulation of microencapsulated articular chondrocytes was also evaluated. Results showed that increasing alginate concentration and thus viscosity increased overall microcapsule size but also affected the geometry towards ellipsoidal-shaped gels. Altering the electric field strength and needle diameter regulated microcapsule size towards a smaller diameter with increasing voltage and smaller needle diameter. Needle size did not appear to affect cell viability when operating with lower alginate concentrations (1% and 2%), although higher concentrations (3%) and thus higher viscosity hydrogels resulted in diminished viability with decreasing needle diameter. Increasing cell density resulted in decreased cell viability and a concomitant decrease in DNA content, perhaps due to competing nutrient demands as a result of more closely packed cells. However, higher cell densities resulted in increased levels of extracellular matrix accumulated. Overall, this work highlights the potential of EHDS as a controllable and versatile approach to fabricate microcapsules for injectable delivery which can be used in a variety of applications such as drug development or cell therapies. . © 2018 IOP Publishing Ltd.

Enhanced sialylation and in vivo efficacy of recombinant human α-galactosidase through in vitro glycosylation

PubMed Central

Sohn, Youngsoo; Lee, Jung Mi; Park, Heung-Rok; Jung, Sung-Chul; Park, Tai Hyun; Oh, Doo-Byoung

2013-01-01

Human α-galactosidase A (GLA) has been used in enzyme replacement therapy for patients with Fabry disease. We expressed recombinant GLA from Chinese hamster ovary cells with very high productivity. When compared to an approved GLA (agalsidase beta), its size and charge were found to be smaller and more neutral. These differences resulted from the lack of terminal sialic acids playing essential roles in the serum half-life and proper tissue targeting. Because a simple sialylation reaction was not enough to increase the sialic acid content, a combined reaction using galactosyltransferase, sialyltransferase, and their sugar substrates at the same time was developed and optimized to reduce the incubation time. The product generated by this reaction had nearly the same size, isoelectric points, and sialic acid content as agalsidase beta. Furthermore, it had better in vivo efficacy to degrade the accumulated globotriaosylceramide in target organs of Fabry mice compared to an unmodified version. [BMB Reports 2013; 46(3): 157-162] PMID:23527859

Porous poly(L-lactic acid) sheet prepared by stretching with starch particles as filler for tissue engineering.

PubMed

Ju, Dandan; Han, Lijing; Li, Zonglin; Chen, Yunjing; Wang, Qingjiang; Bian, Junjia; Dong, Lisong

2016-05-20

Porous poly(L-lactic acid) (PLLA) sheets were prepared by uniaxial stretching PLLA sheets containing starch filler. Here, the starch filler content, stretching ratio, stretching rate and stretching temperature are important factors to influence the structure of the porous PLLA sheets, therefore, they have been investigated in detail. The pore size distribution and tortuosity were characterized by Mercury Intrusion Porosimetry. The results revealed that the porosity and pore size enlarged with the increase of the starch filler content and stretching ratio, while shrank with the rise of stretching temperature. On the other hand, the pore structure almost had no changes with the stretching rate ranging between 5 and 40 mm/min. In order to test and verify that the porous PLLA sheet was suitable for the tissue engineering, the starch particles were removed by selective enzymatic degradation and its in vitro biocompatibility to osteoblast-like MC3T3-E1 cells was investigated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Report of prochloron research, IPE-7 (Palau, February 1982)

NASA Technical Reports Server (NTRS)

Lewin, R. A.; Cheng, L.

1983-01-01

Various aspects of Prochloron research are discussed. At suitable low-tide periods about 5-6 new sites were surveyed as possible convenient sources of symbiotic didemnids. The Kanori Channel site peviously surveyed during IPE-VI remains by far the best, in terms of species, quantities and accessibility. Prochloron from the six major species of symbiotic didemnids was compared serum, cell size and vacuolation, etc. Tadpoles from Lissoclinum patella colonies were observed emerging from cloacal apertures; about 400 were collected. All but 4 carried a girdle of symbiotic Prochloron cells (about 40,000 per larva). Observations were made on cell viability indicated that a marked increase in protoplasm viscosity of the cell contents was associated with cell death. Living cells, in 5 microlitres of buffered sea water under a coverslip, when pressed with a 2 kg weight for 10 seconds, attempts made to culture Prochloron in sea-water media.

Hydrothermal synthesis and characterization of hydroxyapatite and fluorhydroxyapatite nano-size powders.

PubMed

Montazeri, Leila; Javadpour, Jafar; Shokrgozar, Mohammad Ali; Bonakdar, Shahin; Javadian, Sayfoddin

2010-08-01

Pure hydroxyapatite (HAp) and fluoride-containing apatite powders (FHAp) were synthesized using a hydrothermal method. The powders were assessed by x-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM) and F-selective electrode. X-ray diffraction results revealed the formation of single phase apatite structure for all the compositions synthesized in this work. However, the addition of a fluoride ion led to a systematic shift in the (3 0 0) peak of the XRD pattern as well as modifications in the FTIR spectra. It was found that the efficiency of fluoride ion incorporation decreased with the increase in the fluoride ion content. Fluorine incorporation efficiency was around 60% for most of the FHAp samples prepared in the current study. Smaller and less agglomerated particles were obtained by fluorine substitution. The bioactivity of the powder samples with different fluoride contents was compared by performing cell proliferation, alkaline phosphatase (ALP) and Alizarin red staining assays. Human osteoblast cells were used to assess the cellular responses to the powder samples in this study. Results demonstrated a strong dependence of different cell activities on the level of fluoridation.

Efficient MRI labeling of endothelial progenitor cells: design of thiolated surface stabilized superparamagnetic iron oxide nanoparticles.

PubMed

Shahnaz, Gul; Kremser, Christian; Reinisch, Andreas; Vetter, Anja; Laffleur, Flavia; Rahmat, Deni; Iqbal, Javed; Dünnhaupt, Sarah; Salvenmoser, Willi; Tessadri, Richard; Griesser, Ulrich; Bernkop-Schnürch, Andreas

2013-11-01

The aim of this study was to design thiolated surface stabilized superparamagnetic iron oxide nanoparticles (TSS-SPIONs) for efficient internalization with high MRI sensitivity. TSS-SPIONs were developed by chelation between thiolated chitosan-thioglycolic acid (chitosan-TGA) hydrogel and iron ions (Fe(2+)/Fe(3+)). Likely, unmodified chitosan hydrogel SPIONs (UC-SPIONs) and uncoated SPIONs were used as control. Moreover, TSS-SPIONs were investigated regarding to their iron core size, hydrodynamic diameter, zeta potential, iron contents, molar relaxivities (r1 and r2), and cellular internalization. TSS-SPIONs demonstrated an iron oxide core diameter (crystallite size by XRD) of 3.1 ± 0.02 nm, a hydrodynamic diameter of 94 ± 20 nm, a zeta potential of +21 ± 5 mV, and an iron content of 3.6 ± 0.9 mg/mL. In addition, internalization of TSS-SPIONs into human endothelial progenitor cells (EPC) from umbilical cord blood was more than threefold and 17-fold higher in contrast to UC-SPIONs and SPIONs, respectively. With twofold lower incubation iron concentration of TSS-SPIONs, more than threefold higher internalization was achieved as compared to Resovist®. Also, cell viability of more than 90% was observed in the presence of TSS-SPIONs after 24h. The molar MR relaxivities (r2) value at 1.5 T was threefold higher than that of Resovist® and demonstrated that TSS-SPIONs have the potential as very effective T2 contrast-enhancement agent. According to these findings, TSS-SPIONs with efficient internalization, lower cytotoxicity, and high MRI sensitivity seem to be promising for cell tracking. Copyright © 2013 Elsevier B.V. All rights reserved.

Circulating exosomes as new biomarkers for brain disease and injury

NASA Astrophysics Data System (ADS)

Graner, Michael W.; Epple, Laura M.; Dusto, Nathaniel L.; Lencioni, Alex M.; Nega, Meheret; Herring, Matthew; Winston, Ben; Madsen, Helen; Bemis, Lynne T.; Anchordoquy, Thomas J.

2013-05-01

Brain diseases such as cancers, neurodegenerative disorders, or trauma are frequently diagnosed with imaging modalities and sometimes with intracranial biopsies. Treatment response is similarly monitored, along with clinical indications. While these technologies provide important windows into the disease state, they fail to provide us a detailed molecular portrait of the disease and of the changes taking place during therapy. Exosomes are virus-sized nanovesicles derived from the endosomal system and are released extracellularly from essentially all cell types. Exosomes contain intracellular entities (proteins, nucleic acids, metabolites), membrane proteins and lipids, and even extracellular proteins bound to them. Exosomes may be considered as mini-surrogates of their cells of origin, with some content common to all cells/exosomes, but some of the content would be cell-specific. These vesicles are found in all biofluids in humans, and are thus accessible to "liquid biopsy" with harvest of vesicles from such fluids. Current challenges are to identify disease-related markers or panels of markers to distinguish the disease state. Here we will show examples of brain tumor markers found in/on exosomes from cell culture and patient sera, and we will suggest that aspects of the biology of disease may have a relevant place in the search for biomarkers.

Defatted wheat germ application: Influence on cookies' properties with regard to its particle size and dough moisture content.

PubMed

Petrović, Jovana; Rakić, Dušan; Fišteš, Aleksandar; Pajin, Biljana; Lončarević, Ivana; Tomović, Vladimir; Zarić, Danica

2017-10-01

The introduction of agro-food industry by-products rich in bioactive compounds represents major challenge in food industry sector. The influence of wheat germ particle size (<150 µm, 150-1000 µm, and 800-2000 µm), wheat germ content (5, 10, and 15%), and dough moisture content (20, 22, and 24%) on chemical, textural, and sensory characteristics of cookies was investigated using the Box-Behnken experimental design. The substitution of wheat flour with wheat germ increased the protein, fat, mineral, and fiber content of the cookies. The particle size of wheat germ affected the textural properties of cookies. As the particle size of wheat germ increased, the hardness of cookies decreased. The color of the cookie was most influenced by the interaction of dough moisture content and wheat germ particle size. Wheat germ level up to 15% had no significant effect on the sensory characteristics of cookies. A suitable combination of defatted wheat germ level, its particle size, and dough moisture content can improve the nutritional value of cookies, without causing a negative effect on the cookies' sensory characteristics.

Paleolatitudinal Gradients in Marine Phytoplankton Composition and Cell Size

NASA Astrophysics Data System (ADS)

Henderiks, J.; Bordiga, M.; Bartol, M.; Šupraha, L.

2014-12-01

Coccolithophores, a prominent group of marine calcifying unicellular algae, are widely studied in context of current and past climate change. We know that marine phytoplankton are sensitive to climatic changes, but the complex interplay of several processes such as warming, changes in nutrient content, and ocean acidification, makes future scenarios difficult to predict. Some taxa may be more susceptible to environmental perturbations than others, as evidenced by significantly different species-specific sensitivities observed in laboratory experiments. However, short-term plastic responses may not translate into longer-term climatic adaptation, nor should we readily extrapolate the behavior of single strains in the laboratory to natural, multi-species assemblages and their interactions in the ocean. The extensive fossil record of coccolithophores (in the form of coccoliths) reveals high morphological and taxonomic diversity and allows reconstructing the cell size of individual taxonomic groups. In a suite of deep-sea drilling sites from the Atlantic Ocean, we document distinct latitudinal gradients in phytoplankton composition and cell size across major climate transitions of the late Eocene - earliest Oligocene, and the middle - late Miocene. With these data we test hypotheses of species migration, phenotypic evolution, as well as the rates of species extinction and speciation in relation to concurrent paleoenvironmental changes during the Cenozoic.

Surface plasmon resonance effect of silver nanoparticles on a TiO2 electrode for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Jung, Haeng-Yun; Yeo, In-Seon; Kim, Tae-Un; Ki, Hyun-Chul; Gu, Hal-Bon

2018-02-01

In this study, we exploit local surface plasmon resonance (LSPR) in order to improve the efficiency of dye-sensitized solar cells (DSSCs). In order to investigate the effect of LSPR, Ag nanoparticles of several sizes were formed using electro-beam equipment; sizes were varied by changing the annealing time. DSSCs were fabricated by coating Ag nanoparticles onto a TiO2 thin film. Finally, TiO2 nanoparticles were layered onto the Ag nanoparticles via a titanium tetra-isopropoxide (TTIP) treatment. This study used nanoparticle-coated TiO2 thin films as photoelectrodes, and manufactured the cell in the unit of the DSSCs. We compared the behavior of the electrical properties of DSSCs depending on the presence or absence of Ag nanoparticles, as well as on the nanoparticle size. The Ag particles did not affect dye adsorption because the content of Ag particles is very low (0.13%) compared to that in TiO2 in the photoelectrode. The DSSCs with LSPR showed increased electric current density compared to those without LSPR, and improved the solar conversion efficiency (η) by 24%. The current density of the DSSCs increased because the light absorption of the dye increased. Therefore, we determined that LSPR affects the electrical properties of DSSCs.

A new approach for the assessment of the toxicity of polyphenol-rich compounds with the use of high content screening analysis

PubMed Central

Golanski, Jacek; Lukasiak, Magdalena; Redzynia, Malgorzata; Dastych, Jaroslaw; Watala, Cezary

2017-01-01

The toxicity of in vitro tested compounds is usually evaluated based on AC50 values calculated from dose-response curves. However, there is a large group of compounds for which a standard four-parametric sigmoid curve fitting may be inappropriate for estimating AC50. In the present study, 22 polyphenol-rich compounds were prioritized from the least to the most toxic based on the total area under and over the dose-response curves (AUOC) in relation to baselines. The studied compounds were ranked across three key cell indicators (mitochondrial membrane potential, cell membrane integrity and nuclear size) in a panel of five cell lines (HepG2, Caco-2, A549, HMEC-1, and 3T3), using a high-content screening (HCS) assay. Regarding AUOC score values, naringin (negative control) was the least toxic phenolic compound. Aronox, spent hop extract and kale leaf extract had very low cytotoxicity with regard to mitochondrial membrane potential and cell membrane integrity, as well as nuclear morphology (nuclear area). Kaempferol (positive control) exerted strong cytotoxic effects on the mitochondrial and nuclear compartments. Extracts from buckthorn bark, walnut husk and hollyhock flower were highly cytotoxic with regard to the mitochondrion and cell membrane, but not the nucleus. We propose an alternative algorithm for the screening of a large number of agents and for identifying those with adverse cellular effects at an early stage of drug discovery, using high content screening analysis. This approach should be recommended for series of compounds producing a non-sigmoidal cell response, and for agents with unknown toxicity or mechanisms of action. PMID:28662177

Bioinoculants: A sustainable approach to maximize the yield of Ethiopian mustard (Brassica carinata L.) under low input of chemical fertilizers.

PubMed

Nosheen, Asia; Bano, Asghari; Ullah, Faizan

2016-02-01

This study aimed to find out the effect of plant growth-promoting rhizobacteria (PGPR; Azospirillum brasilense and Azotobacter vinelandii) either alone or in combination with different doses of nitrogen and phosphate fertilizers on growth, seed yield, and oil quality of Brassica carinata (L.) cv. Peela Raya. PGPR were applied as seed inoculation at 10(6) cells/mL(-1) so that the number of bacterial cells per seed was 2.6 × 10(5) cells/seed. The chemical fertilizers, namely, urea and diammonium phosphate (DAP) were applied in different doses (full dose (urea 160 kg ha(-1) + DAP 180 kg ha(-1)), half dose (urea 80 kg ha(-1) + DAP 90 kg ha(-1)), and quarter dose (urea 40 kg ha(-1) + DAP 45 kg ha(-1)). The chemical fertilizers at full and half dose significantly increased the chlorophyll, carotenoids, and protein content of leaves and the seed yield (in kilogram per hectare) but had no effect on the oil content of seed. The erucic acid (C22:1) content present in the seed was increased. Azospirillum performed better than Azotobacter and its effect was at par with full dose of chemical fertilizers (CFF) for pigments and protein content of leaves when inoculated in the presence of half dose of chemical fertilizers (SPH). The seed yield and seed size were greater. Supplementing Azospirillum with SPH assisted Azospirillum to augment the growth and yield, reduced the erucic acid (C22:1) and glucosinolates contents, and increased the unsaturation in seed oil. It is inferred that A. brasilense could be applied as an efficient bioinoculant for enhancing the growth, seed yield, and oil quality of Ethiopian mustard at low fertilizer costs and sustainable ways. © The Author(s) 2013.

Influence of pore size of porous titanium fabricated by vacuum diffusion bonding of titanium meshes on cell penetration and bone ingrowth.

PubMed

Chang, Bei; Song, Wen; Han, Tianxiao; Yan, Jun; Li, Fuping; Zhao, Lingzhou; Kou, Hongchao; Zhang, Yumei

2016-03-01

The present work assesses the potential of three-dimensional (3D) porous titanium (pore size of 188-390 μm and porosity of 70%) fabricated by vacuum diffusion bonding of titanium meshes for applications in bone engineering. Rat bone marrow mesenchymal stem cells were used to investigate the proliferation and differentiation of cells on titanium scaffolds with different pore sizes at day 7, day 14 and day 21 based on DNA contents, alkaline phosphatase (ALP) activity, collagen (COL) secretion and osteogenic gene expressions including ALP, COL-1, bone morphogenetic protein-2 (BMP-2), osteopontin (OPN), runt-related transcription factor 2 (RUNX2), using smooth solid titanium plate as reference material. The rabbit models with distal femoral condyles defect were used to investigate the bone ingrowth into the porous titanium. All samples were subjected to Micro-CT and histological analysis after 4 and 12 weeks of healing. A one-way ANOVA followed by Tukey post hoc tests was used to analyze the data. It was found that the differentiation stage of cells on the porous titanium delayed compared with the smooth solid titanium plate and Ti 188 was more inclined to promote cell differentiation at the initial stage (day 14) while cell proliferation (day 1, 4, 7, 10, 14 and 21) and bone ingrowth (4 and 12 weeks) were biased to Ti 313 and Ti 390. The study indicates that the hybrid porous implant design which combines the advantages of different pore sizes may be meaningful and promising for bone defect restoration. One of the significant challenges in bone defect restoration is the integration of biomaterials and surrounding bone tissue. Porous titanium may be a promising choice for bone ingrowth and mineralization with appropriate mechanical and biological properties. In this study, based on porous titanium fabricated by vacuum diffusion bonding of titanium meshes, we have evaluated the influence of various pore sizes on rat bone marrow mesenchymal stem cells (rBMMSCs) penetration in vitro and bone ingrowth in vivo. It was interesting that we found the proliferation and differentiation abilities of rBMMSCs, as well as bone ingrowth were related to different pore sizes of such porous scaffolds. The results may provide guidance for porous titanium design for bone defect restoration. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Numerical characterization of micro-cell UO2sbnd Mo pellet for enhanced thermal performance

NASA Astrophysics Data System (ADS)

Lee, Heung Soo; Kim, Dong-Joo; Kim, Sun Woo; Yang, Jae Ho; Koo, Yang-Hyun; Kim, Dong Rip

2016-08-01

Metallic micro-cell UO2 pellet with high thermal conductivity has received attention as a promising accident-tolerant fuel. Although experimental demonstrations have been successful, studies on the potency of current metallic micro-cell UO2 fuels for further enhancement of thermal performance are lacking. Here, we numerically investigated the thermal conductivities of micro-cell UO2sbnd Mo pellets in terms of the amount of Mo content, the unit cell size, and the aspect ratio of the micro-cells. The results showed good agreement with experimental measurements, and more importantly, indicated the importance of optimizing the unit cell geometries of the micro-cell pellets for greater increases in thermal conductivity. Consequently, the micro-cell UO2sbnd Mo pellets (5 vol% Mo) with modified geometries increased the thermal conductivity of the current UO2 pellets by about 2.5 times, and lowered the temperature gradient within the pellets by 62.9% under a linear heat generation rate of 200 W/cm.

Effect of retinal impulse blockage on cytochrome oxidase-poor interpuffs in the macaque striate cortex: quantitative EM analysis of neurons.

PubMed

Wong-Riley, M T; Trusk, T C; Kaboord, W; Huang, Z

1994-09-01

One of the hallmarks of the primate striate cortex is the presence of cytochrome oxidase-rich puffs in its supragranular layers. Neurons in puffs have been classified as type A, B, and C in ascending order of cytochrome oxidase content, with type C cells being the most vulnerable to retinal impulse blockade. The present study aimed at analysing cytochrome oxidase-poor interpuffs with reference to their metabolic cell types and the effect of intraretinal tetrodotoxin treatment. The same three metabolic types were found in interpuffs, except that type B and C neurons were smaller and less cytochrome oxidase-reactive in interpuffs than in puffs. Type A neurons had small perikarya, low levels of cytochrome oxidase, and received exclusively symmetric axosomatic synapses. The largest neurons were pyramidal, type B cells with moderate cytochrome oxidase activity and were also contacted exclusively by symmetric axosomatic synapses. Type C cells medium-sized with a rich supply of large, darkly reactive mitochondria and possessed all the characteristics of GABAergic neurons. They were the only cell type that received both symmetric and asymmetric axosomatic synapses. Two weeks of monocular tetrodotoxin blockade in adult monkeys caused all three major cell types in deprived interpuffs to suffer a significant downward shift in the size and cytochrome oxidase reactivity of their mitochondria, but the effects were more severe in type B and C neurons. In nondeprived interpuffs, all three cell types gained both in size and absolute number of mitochondria, and type A cells also had an elevated level of cytochrome oxidase, indicating that they might be functioning at a competitive advantage over cells in deprived columns. However, type B and C neurons showed a net loss of darkly reactive mitochondria, indicating that these cells became less active. Thus, mature interpuff neurons remained vulnerable to retinal impulse blockade and the metabolic capacity of these cells remains tightly regulated by neuronal activity.

Ternary Blend Composed of Two Organic Donors and One Acceptor for Active Layer of High-Performance Organic Solar Cells.

PubMed

Lee, Jong Won; Choi, Yoon Suk; Ahn, Hyungju; Jo, Won Ho

2016-05-04

Ternary blends composed of two donor absorbers with complementary absorptions provide an opportunity to enhance the short-circuit current and thus the power conversion efficiency (PCE) of organic solar cells. In addition to complementary absorption of two donors, ternary blends may exhibit favorable morphology for high-performance solar cells when one chooses properly the donor pair. For this purpose, we develop a ternary blend with two donors (diketopyrrolopyrrole-based polymer (PTDPP2T) and small molecule ((TDPP)2Ph)) and one acceptor (PC71BM). The solar cell made of a ternary blend with 10 wt % (TDPP)2Ph exhibits higher PCE of 7.49% as compared with the solar cells with binary blends, PTDPP2T:PC71BM (6.58%) and (TDPP)2Ph:PC71BM (3.21%). The higher PCE of the ternary blend solar cell is attributed mainly to complementary absorption of two donors. However, a further increase in (TDPP)2Ph content in the ternary blend (>10 wt %) decreases the PCE. The ternary blend with 10 wt % (TDPP)2Ph exhibits well-developed morphology with narrow-sized fibrils while the blend with 15 wt % (TDPP)2Ph shows phase separation with large-sized domains, demonstrating that the phase morphology and compatibility of ternary blend are important factors to achieve a high-performance solar cell made of ternary blends.

Increasing seed size and quality by manipulating BIG SEEDS1 in legume species

PubMed Central

Ge, Liangfa; Yu, Jianbin; Wang, Hongliang; Luth, Diane; Bai, Guihua; Wang, Kan

2016-01-01

Plant organs, such as seeds, are primary sources of food for both humans and animals. Seed size is one of the major agronomic traits that have been selected in crop plants during their domestication. Legume seeds are a major source of dietary proteins and oils. Here, we report a conserved role for the BIG SEEDS1 (BS1) gene in the control of seed size and weight in the model legume Medicago truncatula and the grain legume soybean (Glycine max). BS1 encodes a plant-specific transcription regulator and plays a key role in the control of the size of plant organs, including seeds, seed pods, and leaves, through a regulatory module that targets primary cell proliferation. Importantly, down-regulation of BS1 orthologs in soybean by an artificial microRNA significantly increased soybean seed size, weight, and amino acid content. Our results provide a strategy for the increase in yield and seed quality in legumes. PMID:27791139

Synthesis of silica-PAMAM dendrimer nanoparticles as promising carriers in Neuro blastoma cells.

PubMed

Yesil-Celiktas, Ozlem; Pala, Cansu; Cetin-Uyanikgil, E Oyku; Sevimli-Gur, Canan

2017-02-15

Mesoporous silica carriers are emerging as therapeutic drug delivery systems. The objective of this study was to develop a formulation for synthesizing silica-PAMAM dendrimer hybrid nanoparticles with sol-gel technique. Subsequently, black carrot anthocyanins were encapsulated and investigated for their capability in terms of inhibiting the proliferative effects of neuroblastoma (Neuro 2A). In this context, particle size distributions were ascertained followed by thermal analysis (DSC), scanning electron microscopy and encapsulation efficiency. Subsequently, in vitro release kinetics was determined along with cytotoxicity of empty and anthocyanin doped hybrid nanoparticles. The lowest particle size was 134.8 nm with a zeta potential of +19.78 mV which enhanced electrostatic interaction with the cell membrane in the cytotoxicity analyses. As the anthocyanin content was totally released at the end of 6 days, the cytotoxicity was observed for 134 h, reaching an inhibition of 87.9%. On the other hand, Neuro 2A cells incubated with empty nanoparticles exhibited a high proliferation indicating that hybrid nanoparticles were not toxic to the cells and the inhibitory effect was associated with the anthocyanins. Copyright © 2016 Elsevier Inc. All rights reserved.

AN OSMOTIC SYSTEM WITHIN THE CYTOPLASM OF CELLS

PubMed Central

Opie, Eugene L.

1948-01-01

The cytoplasm of cells of the liver and of the kidney is in large part occupied by bodies which respond to the water content of these cells and are modified by dissolved substances in the surrounding fluid or by physical change such as freezing. These bodies, in part mitochondria but designated more broadly cytochondria, constitute an osmotic system within the cytoplasm of cells. When the specific gravity of liver or kidney tissue is used as an index of changes in the water content of tissue, swelling of cytochondria in general follows the intake of water but this relation may be modified by a variety of conditions. When liver that has been frozen and thawed is immersed in water, cytochondria become swollen though the containing cells diminish in size. Solutions of sodium and of potassium chloride isotonic with blood plasma cause delayed swelling of cells and cytochondria, greater with the potassium salt; solutions of calcium chloride of equal molar concentration cause immediate swelling of cells and cytochondria. The basophile material of the cytoplasm (ribonucleic acid and related substances) and the material that gives to mitochondria their characteristic stain are removed by immersion in water but their disappearance is retarded by isotonic solutions of sodium or of potassium chloride and further delayed by hypertonic solutions. When the intensity of staining reactions is diminished by the partial loss of basophile substance or of the distinctive mitochondrial material, these are found at the surfaces of the cytoplasmic bodies, held perhaps by adsorption. When water, isotonic solutions of sodium chloride, or Ringer's solution comes into contact with immersed liver, they remove basophile and mitochondrial material from a superficial zone and substances with similar staining reactions appear in the cytoplasm of cells at a deeper level. Osmotic changes in the cytoplasmic bodies may be reversible. When liver tissue which has been for a short time immersed in water is transferred to a solution that is approximately isotonic in relation to blood plasma, swollen cytochondria return in part or completely to their former size; but with continued immersion in water, this reversibility becomes increasingly less complete. PMID:18912893

The impact of mobile phone screen size on user comprehension of health information.

PubMed

Alghamdi, Ebtisam; Yunus, Faisel; Househ, Mowafa

2013-01-01

Within the field of mobile health, there is little research conducted on the impacts of mobile health technologies and applications on user comprehension of health content. In this study, we examine the difference between small, medium and large screen mobile phone that affect the user comprehension of health content. We designed an experimental study where 33 users read the contents of a health application on different mobile phone screen sizes. Each participant was timed, tracked for correctness, and gave ratings for both readability and satisfaction on each task. In addition, they were asked some questions about the contents. Results show that there was no significant impact of the screen size on user comprehension of the contents. However, it was found that participants with small screen size took longer to read the health contents.

Bioinformatics analysis of disordered proteins in prokaryotes

PubMed Central

2011-01-01

Background A significant number of proteins have been shown to be intrinsically disordered, meaning that they lack a fixed 3 D structure or contain regions that do not posses a well defined 3 D structure. It has also been proven that a protein's disorder content is related to its function. We have performed an exhaustive analysis and comparison of the disorder content of proteins from prokaryotic organisms (i.e., superkingdoms Archaea and Bacteria) with respect to functional categories they belong to, i.e., Clusters of Orthologous Groups of proteins (COGs) and groups of COGs-Cellular processes (Cp), Information storage and processing (Isp), Metabolism (Me) and Poorly characterized (Pc). We also analyzed the disorder content of proteins with respect to various genomic, metabolic and ecological characteristics of the organism they belong to. We used correlations and association rule mining in order to identify the most confident associations between specific modalities of the characteristics considered and disorder content. Results Bacteria are shown to have a somewhat higher level of protein disorder than archaea, except for proteins in the Me functional group. It is demonstrated that the Isp and Cp functional groups in particular (L-repair function and N-cell motility and secretion COGs of proteins in specific) possess the highest disorder content, while Me proteins, in general, posses the lowest. Disorder fractions have been confirmed to have the lowest level for the so-called order-promoting amino acids and the highest level for the so-called disorder promoters. For each pair of organism characteristics, specific modalities are identified with the maximum disorder proteins in the corresponding organisms, e.g., high genome size-high GC content organisms, facultative anaerobic-low GC content organisms, aerobic-high genome size organisms, etc. Maximum disorder in archaea is observed for high GC content-low genome size organisms, high GC content-facultative anaerobic or aquatic or mesophilic organisms, etc. Maximum disorder in bacteria is observed for high GC content-high genome size organisms, high genome size-aerobic organisms, etc. Some of the most reliable association rules mined establish relationships between high GC content and high protein disorder, medium GC content and both medium and low protein disorder, anaerobic organisms and medium protein disorder, Gammaproteobacteria and low protein disorder, etc. A web site Prokaryote Disorder Database has been designed and implemented at the address http://bioinfo.matf.bg.ac.rs/disorder, which contains complete results of the analysis of protein disorder performed for 296 prokaryotic completely sequenced genomes. Conclusions Exhaustive disorder analysis has been performed by functional classes of proteins, for a larger dataset of prokaryotic organisms than previously done. Results obtained are well correlated to those previously published, with some extension in the range of disorder level and clear distinction between functional classes of proteins. Wide correlation and association analysis between protein disorder and genomic and ecological characteristics has been performed for the first time. The results obtained give insight into multi-relationships among the characteristics and protein disorder. Such analysis provides for better understanding of the evolutionary process and may be useful for taxon determination. The main drawback of the approach is the fact that the disorder considered has been predicted and not experimentally established. PMID:21366926

Preparation of poly-L-lysine functionalized magnetic nanoparticles and their influence on viability of cancer cells

NASA Astrophysics Data System (ADS)

Khmara, I.; Koneracka, M.; Kubovcikova, M.; Zavisova, V.; Antal, I.; Csach, K.; Kopcansky, P.; Vidlickova, I.; Csaderova, L.; Pastorekova, S.; Zatovicova, M.

2017-04-01

This study was aimed at development of biocompatible amino-functionalized magnetic nanoparticles as carriers of specific antibodies able to detect and/or target cancer cells. Poly-L-lysine (PLL)-modified magnetic nanoparticle samples with different PLL/Fe3O4 content were prepared and tested to define the optimal PLL/Fe3O4 weight ratio. The samples were characterized for particle size and morphology (SEM, TEM and DLS), and surface properties (zeta potential measurements). The optimal PLL/Fe3O4 weight ratio of 1.0 based on both zeta potential and DLS measurements was in agreement with the UV/VIS measurements. Magnetic nanoparticles with the optimal PLL content were conjugated with antibody specific for the cancer biomarker carbonic anhydrase IX (CA IX), which is induced by hypoxia, a physiologic stress present in solid tumors and linked with aggressive tumor behavior. CA IX is localized on the cell surface with the antibody-binding epitope facing the extracellular space and is therefore suitable for antibody-based targeting of tumor cells. Here we showed that PLL/Fe3O4 magnetic nanoparticles exhibit cytotoxic activities in a cell type-dependent manner and bind to cells expressing CA IX when conjugated with the CA IX-specific antibody. These data support further investigations of the CA IX antibody-conjugated, magnetic field-guided/activated nanoparticles as tools in anticancer strategies.

Fabrication of genetically engineered polypeptide@quantum dots hybrid nanogels for targeted imaging

NASA Astrophysics Data System (ADS)

Yang, Jie; Yao, Ming-Hao; Zhao, Dong-Hui; Zhang, Xiao-Shuai; Jin, Rui-Mei; Zhao, Yuan-Di; Liu, Bo

2017-08-01

Nanogels have been widely used as multifunctional drug delivery carriers because of high water content, biocompatibility, and high loading capability. We designed and biosynthesized two triblock artificial polypeptides PC10A and PC10ARGD as vehicles for encapsulating hydrophobic materials. These polypeptides can form nanogels by self-assembly when the concentration is below 2% ( w/ v). The physical properties of nanogels, including size, surface potential, and targeting domain, are able to be tuned. Hydrophobic materials from molecular size to nano-size can be loaded into the polypeptide nanogels to form hybrid nanogels. Hydrophobic quantum dots CdSe@ZnS below 10 nM were loaded into the polypeptide nanogels by ultrasonic treatment. Encapsulation endows hydrophobic QDs with good tunability of size, water solubility, stability, targeting, and biocompatibility. PC10ARGD nanogels and PC10ARGD@QDs hybrid nanogels showed excellent biocompatibility, which the cellular viabilities of HeLa and MCF-7 cells treated with 1% PC10ARGD nanogels and PC10ARGD@QDs hybrid nanogels contained 20 nM QDs were above 90 and 80%, respectively. PC10ARGD@QDs hybrid nanogels with an arginine-glycine-aspartic acid motif present efficient receptor-mediated endocytosis in α v β 3 overexpressing HeLa cells but not in the control MCF-7 cells as analyzed by confocal microscopy. These results demonstrate that such polypeptide nanogels as nanocarriers are expected to have great potential applications in biomedicine.

Cell wall canals formed upon growth of Candida maltosa in the presence of hexadecane are associated with polyphosphates.

PubMed

Zvonarev, Anton N; Crowley, David E; Ryazanova, Lubov P; Lichko, Lydia P; Rusakova, Tatiana G; Kulakovskaya, Tatiana V; Dmitriev, Vladimir V

2017-05-01

Canals are supramolecular complexes observed in the cell wall of Candida maltosa grown in the presence of hexadecane as a sole carbon source. Such structures were not observed in glucose-grown cells. Microscopic observations of cells stained with diaminobenzidine revealed the presence of oxidative enzymes in the canals. 4΄,6΄-diamino-2-phenylindole staining revealed that a substantial part of cellular polyphosphate was present in the cell wall of cells grown on hexadecane in condition of phosphate limitation. The content and chain length of polyphosphates were higher in hexadecane-grown cells than in glucose grown ones. The treatment of cells with yeast polyphosphatase PPX1 resulted in the decrease of the canal size. These data clearly indicated that polyphosphates are constituents of canals; they might play an important role in the canal structure and functioning. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Challenges of flow-cytometric estimation of nuclear genome size in orchids, a plant group with both whole-genome and progressively partial endoreplication.

PubMed

Trávníček, Pavel; Ponert, Jan; Urfus, Tomáš; Jersáková, Jana; Vrána, Jan; Hřibová, Eva; Doležel, Jaroslav; Suda, Jan

2015-10-01

Nuclear genome size is an inherited quantitative trait of eukaryotic organisms with both practical and biological consequences. A detailed analysis of major families is a promising approach to fully understand the biological meaning of the extensive variation in genome size in plants. Although Orchidaceae accounts for ∼10% of the angiosperm diversity, the knowledge of patterns and dynamics of their genome size is limited, in part due to difficulties in flow cytometric analyses. Cells in various somatic tissues of orchids undergo extensive endoreplication, either whole-genome or partial, and the G1-phase nuclei with 2C DNA amounts may be lacking, resulting in overestimated genome size values. Interpretation of DNA content histograms is particularly challenging in species with progressively partial endoreplication, in which the ratios between the positions of two neighboring DNA peaks are lower than two. In order to assess distributions of nuclear DNA amounts and identify tissue suitable for reliable estimation of nuclear DNA content, we analyzed six different tissue types in 48 orchid species belonging to all recognized subfamilies. Although traditionally used leaves may provide incorrect C-values, particularly in species with progressively partial endoreplication, young ovaries and pollinaria consistently yield 2C and 1C peaks of their G1-phase nuclei, respectively, and are, therefore, the most suitable parts for genome size studies in orchids. We also provide new DNA C-values for 22 orchid genera and 42 species. Adhering to the proposed methodology would allow for reliable genome size estimates in this largest plant family. Although our research was limited to orchids, the need to find a suitable tissue with dominant 2C peak of G1-phase nuclei applies to all endopolyploid species. © 2015 International Society for Advancement of Cytometry.

Combustion-Derived Ultrafine Particles Transport Organic Toxicants to Target Respiratory Cells

PubMed Central

Penn, Arthur; Murphy, Gleeson; Barker, Steven; Henk, William; Penn, Lynn

2005-01-01

Epidemiologic evidence supports associations between inhalation of fine and ultrafine ambient particulate matter [aerodynamic diameter ≤ 2.5 μm (PM2.5)] and increases in cardiovascular/respiratory morbidity and mortality. Less attention has been paid to how the physical and chemical characteristics of these particles may influence their interactions with target cells. Butadiene soot (BDS), produced during combustion of the high-volume petrochemical 1,3-butadiene, is rich in polynuclear aromatic hydrocarbons (PAHs), including known carcinogens. We conducted experiments to characterize BDS with respect to particle size distribution, assembly, PAH composition, elemental content, and interaction with respiratory epithelial cells. Freshly generated, intact BDS is primarily (> 90%) PAH-rich, metals-poor (nickel, chromium, and vanadium concentrations all < 1 ppm) PM2.5, composed of uniformly sized, solid spheres (30–50 nm) in aggregated form. Cells of a human bronchial epithelial cell line (BEAS-2B) exhibit sequential fluorescent responses—a relatively rapid (~ 30 min), bright but diffuse fluorescence followed by the slower (2–4 hr) appearance of punctate cytoplasmic fluorescence—after BDS is added to medium overlying the cells. The fluorescence is associated with PAH localization in the cells. The ultrafine BDS particles move down through the medium to the cell membrane. Fluorescent PAHs are transferred from the particle surface to the cell membrane, cross the membrane into the cytosol, and appear to accumulate in lipid vesicles. There is no evidence that BDS particles pass into the cells. The results demonstrate that uptake of airborne ultrafine particles by target cells is not necessary for transfer of toxicants from the particles to the cells. PMID:16079063

Combustion-derived ultrafine particles transport organic toxicants to target respiratory cells.

PubMed

Penn, Arthur; Murphy, Gleeson; Barker, Steven; Henk, William; Penn, Lynn

2005-08-01

Epidemiologic evidence supports associations between inhalation of fine and ultrafine ambient particulate matter [aerodynamic diameter < or = 2.5 microm (PM2.5)] and increases in cardiovascular/respiratory morbidity and mortality. Less attention has been paid to how the physical and chemical characteristics of these particles may influence their interactions with target cells. Butadiene soot (BDS), produced during combustion of the high-volume petrochemical 1,3-butadiene, is rich in polynuclear aromatic hydrocarbons (PAHs), including known carcinogens. We conducted experiments to characterize BDS with respect to particle size distribution, assembly, PAH composition, elemental content, and interaction with respiratory epithelial cells. Freshly generated, intact BDS is primarily (> 90%) PAH-rich, metals-poor (nickel, chromium, and vanadium concentrations all < 1 ppm) PM2.5, composed of uniformly sized, solid spheres (30-50 nm) in aggregated form. Cells of a human bronchial epithelial cell line (BEAS-2B) exhibit sequential fluorescent responses--a relatively rapid (approximately 30 min), bright but diffuse fluorescence followed by the slower (2-4 hr) appearance of punctate cytoplasmic fluorescence--after BDS is added to medium overlying the cells. The fluorescence is associated with PAH localization in the cells. The ultrafine BDS particles move down through the medium to the cell membrane. Fluorescent PAHs are transferred from the particle surface to the cell membrane, cross the membrane into the cytosol, and appear to accumulate in lipid vesicles. There is no evidence that BDS particles pass into the cells. The results demonstrate that uptake of airborne ultrafine particles by target cells is not necessary for transfer of toxicants from the particles to the cells.

Endoreduplication intensity as a marker of seed developmental stage in the Fabaceae.

PubMed

Rewers, Monika; Sliwinska, Elwira

2012-12-01

Flow cytometry (FCM) can be used to study cell cycle activity in developing, mature and germinating seeds. It provides information about a seed's physiological state and therefore can be used by seed growers for assessing optimal harvest times and presowing treatments. Because an augmented proportion of 4C nuclei usually is indicative of high mitotic activity, the 4C/2C ratio is commonly used to follow the progress of seed development and germination. However, its usefulness for polysomatic (i.e., containing cells with different DNA content) seeds is questioned. Changes in cell cycle/endoreduplication activity in developing seeds of five members of the Fabaceae were studied to determine a more suitable marker of seed developmental stages for polysomatic species based on FCM measurements. Seeds of Phaseolus vulgaris, Medicago sativa, Pisum sativum, Vicia sativa, and Vicia faba var. minor were collected 20, 30, 40, 50, and 60 days after flowering (DAF), embryos were isolated and the proportion of nuclei with different DNA contents in the embryo axis and cotyledon was established. The ratios 4C/2C and (Σ>2C)/2C were calculated. Dried seeds were subjected to laboratory germination tests following international seed testing association (ISTA) rules. Additionally, the absolute nuclear DNA content was estimated in the leaves of the studied species. During seed development nuclei with DNA contents from 2C to 128C were detected; the endopolyploidy pattern depended on the species, seed organ and developmental stage. The cell cycle/endoreduplication parameters correlated negatively with genome size. The (Σ>2C)/2C ratio in the cotyledons reflected the seed developmental stage and corresponded with seed germinability. Therefore, this ratio is recommended as a marker in polysomatic seed research and production instead of the 4C/2C ratio, which does not consider the occurrence of endopolyploid cells. Copyright © 2012 International Society for Advancement of Cytometry.

Measuring Solvent Content of Macromolecular Crystals Using Fluorescence Recovery after Photobleaching

NASA Astrophysics Data System (ADS)

Siewny, Matthew; Kmetko, Jan

2010-10-01

We work out a novel protocol for measuring the solvent content (the fraction of crystal volume occupied by solvent) in biological crystals by the technique of fluorescence recovery after photobleaching (FRAP). Crystals of proteins with widely varying known solvent content (lysozyme, thaumatin, catalase, and ferritin) were grown in their native solution doped with sodium fluorescein dye and hydroxylamine (to prevent dye from binding to amine groups of the proteins.) The crystals were irradiated by a broadband, high intensity light through knife slits, leaving a rectangular area of bleached dye within the crystals. Measuring the flow of dye out of the bleached area allowed us to construct a curve relating the diffusion coefficient of dye to the channel size within the crystals, by solving the diffusion equation analytically. This curve may be used to measure the solvent content of any biological crystal in its native solution and help determine the number of proteins in the crystallographic asymmetric unit cell in x-ray structure solving procedures.

Expression of metallocarboxypeptidase inhibitors in Escherichia coli: effect of cysteine content and protein size in the secretory production of disulfide-bridged proteins.

PubMed

Puertas, Juan-Miguel; Caminal, Glòria; González, Glòria

2011-09-01

Metallocarboxypeptidase inhibitors are proteins with possible applications in biomedicine given their properties as anticoagulant and antitumoral factors. They are small, eukaryotic polypeptides comprising several disulfide bridges, which makes them hard to express in inexpensive bacterial hosts. In this work, three of them were produced in high-cell-density cultures of Escherichia coli: PCI (39 residues and three bridges), LCI (66 residues and four bridges) and TCI (75 residues and six bridges). The genes coding for the mentioned inhibitors were cloned in an arabinose-inducible plasmid fused to the signal peptide of DsbA in order to have them secreted and grant the formation of the bridges. The trigger-factor defective strain KTD101 was used as the expression host. The resulting recombinant strains were cultured in fed-batch mode employing minimal media and an exponential feed profile, keeping the specific growth rate at μ = 0.1 h(-1) by limitation of the fed carbon source (glycerol). Between 380 and 540 mg l(-1) of active inhibitors were obtained in both the periplasmic extracts and extracellular media of the cultures. Later on, excretion was enhanced using a cell permeabilization treatment, allowing the recovery of over 80% of the products from the extracellular fraction. Protein yields were found to be inversely proportional to cysteine content of the inhibitor, whereas protein excretion rates were inversely proportional to the protein size. Overall, these results offer insight into the secretory production of active disulfide-bridged proteins in high-cell-density cultures of E. coli.

Genome size and metabolic intensity in tetrapods: a tale of two lines

PubMed Central

Vinogradov, Alexander E; Anatskaya, Olga V

2005-01-01

We show the negative link between genome size and metabolic intensity in tetrapods, using the heart index (relative heart mass) as a unified indicator of metabolic intensity in poikilothermal and homeothermal animals. We found two separate regression lines of heart index on genome size for reptiles–birds and amphibians–mammals (the slope of regression is steeper in reptiles–birds). We also show a negative correlation between GC content and nucleosome formation potential in vertebrate DNA, and, consistent with this relationship, a positive correlation between genome GC content and nuclear size (independent of genome size). It is known that there are two separate regression lines of genome GC content on genome size for reptiles–birds and amphibians–mammals: reptiles–birds have the relatively higher GC content (for their genome sizes) compared to amphibians–mammals. Our results suggest uniting all these data into one concept. The slope of negative regression between GC content and nucleosome formation potential is steeper in exons than in non-coding DNA (where nucleosome formation potential is generally higher), which indicates a special role of non-coding DNA for orderly chromatin organization. The chromatin condensation and nuclear size are supposed to be key parameters that accommodate the effects of both genome size and GC content and connect them with metabolic intensity. Our data suggest that the reptilian–birds clade evolved special relationships among these parameters, whereas mammals preserved the amphibian-like relationships. Surprisingly, mammals, although acquiring a more complex general organization, seem to retain certain genome-related properties that are similar to amphibians. At the same time, the slope of regression between nucleosome formation potential and GC content is steeper in poikilothermal than in homeothermal genomes, which suggests that mammals and birds acquired certain common features of genomic organization. PMID:16519230

Crystal-Chemical Correlations in Chromites from Kimberlitic and Non-Kimberlitic Sources.

NASA Astrophysics Data System (ADS)

Freckelton, C. N.; Flemming, R. L.

2009-05-01

This study explores the utility of micro X-ray diffraction (μXRD) as a tool for diamond exploration, as a compliment to current industry-standard techniques such as electron probe microanalysis (EPMA). Here we examine chromite. As one of the first phases to crystallize in mantle rocks, it is a useful indicator of upper mantle magmatic conditions in rocks that have been sampled by kimberlites. In addition, chromite does not alter easily from chemical and physical weathering processes. As such, chromite is a useful kimberlite indicator mineral in diamond exploration. We present correlations between crystal structure (unit cell) and chemical composition of chromite, (Fe,Mg)[Cr, Al]2O4, using correlated μXRD and EPMA data for 133 chromites from a three source locations: Two kimberlite sources and one non-kimberlitic source from an Archean granite/greenstone terrain. Quantitative analysis was performed using Electron Probe Microanalysis (EPMA) at Mineral Services, South Africa, prior to the loan of the samples. Randomly-oriented chromite grains, approximately 500 μm in diameter, were analyzed as previously mounted for EPMA. Micro X-ray-diffraction was performed using a Bruker D8-Discover Diffractometer, with θ-θ geometry, with CuKα radiation, operating at 40 kV and 40 mA, with nominal beam diameter of 500 μm. The data were collected in omega scan mode. Two dimensional General Area Detector Diffraction System (GADDS) images were collected for 20 minutes per image, and integrated to produce one-dimensional plots of intensity versus 2θ, for subsequent unit cell refinement using CELREF. Although all samples in this study were considered to be 'chromite', a plot of Cr/(Cr+Al) versus Fe2+/(Fe2++Mg) shows extensive substitution among four dominant members: chromite (FeCr2O4), magnesio-chromite (MgCr2O4), spinel (MgAl2O4), and hercynite (FeAl2O4), where Mg and Fe2+ substitute for one another on the tetrahedral site, and Cr and Al substitute for one another on the octahedral site. Our data are widely variable as compared to the field occupied by chromite inclusions in diamonds (high Cr and Mg (˜60 wt %) and very low Ti (˜0.40 wt %). Plots of the unit cell parameter, ao, versus composition demonstrate a decrease in unit cell size with increasing Al content (and corresponding decrease in Cr content), consistent with a smaller cation radius for Al versus Cr (Al=0.675 Å and Cr=0.905 Å). The trend in unit cell size is unlikely to be effected by Mg-Fe substitution because of the very small difference in their tetrahedral cation radii (Fe2+=0.835 Å and Mg=0.86 Å). Initial plots of composition versus unit cell parameter were clearly able to distinguish a difference between unit cell of kimberlitic chromites and non-kimberlitic chromites. The significantly higher Cr content in kimberlitic chromites (radius=0.905 Å), and correspondingly higher Al content in non-kimberlitic chromites (radius=0.675 Å), results in a striking bimodal distribution in unit cell parameter, ao, where kimberlitic chromites have a larger unit cell (> 8.3 Å) than non-kimberlitic chromites (< 8.3 Å). This preliminary data provides a useful starting point for screening minerals from naturally relevant chromite solid solutions using their corresponding unit cell parameters. Future work will examine which site substitutions (octahedral versus tetrahedral) are affecting the unit cell as well as the effect of cation order-disorder on unit cell parameters.

Hyaluronan and Its Binding Proteins during Cervical Ripening and Parturition: Dynamic Changes in Size, Distribution and Temporal Sequence

PubMed Central

Ruscheinsky, Monika; De la Motte, Carol; Mahendroo, Mala

2008-01-01

The uterine cervix undergoes changes during pregnancy and labor that transform it from a closed, rigid, collagen dense structure to one that is distensible, has a disorganized collagen matrix, and dilates sufficiently to allow birth. To protect the reproductive tract from exposure to the external environment, the cervix must be rapidly altered to a closed, undistensible structure after birth. Preparturition remodeling is characterized by increased synthesis of hyaluronan, decreased expression of collagen assembly genes and increased distribution of inflammatory cells into the cervical matrix. Postpartum remodeling is characterized by decreased hyaluronan (HA) content, increased expression of genes involved in assembly of mature collagen and inflammation. The focus of this study is to advance our understanding of functions HA plays in this dynamic process through characterization of HA size, structure and binding proteins in the mouse cervix. Changes in size and structure of HA before and after birth were observed as well as cell specific expression of HA binding proteins. CD44 expression is localized to the pericellular matrix surrounding the basal epithelia and on immune cells while inter α trypsin inhibitor (IαI) and versican are localized to the stromal matrix. Co-localization of HA and IαI is most pronounced after birth. Upregulation of the versican degrading protease, ADAMTS1 occurs in the cervix prior to birth. These studies suggest that HA has multiple, cell specific functions in the cervix that may include modulation of tissue structure and integrity, epithelial cell migration and differentiation, and inflammatory responses. PMID:18353623

Liver fat content is linked to inflammatory changes in subcutaneous adipose tissue in type 2 diabetes patients.

PubMed

Jansen, Henry J; Vervoort, Gerald M; van der Graaf, Marinette; Stienstra, Rinke; Tack, Cees J

2013-11-01

Patients with type 2 diabetes mellitus (T2DM) are typically overweight and have an increased liver fat content (LFAT). High LFAT may be explained by an increased efflux of free fatty acids from the adipose tissue, which is partly instigated by inflammatory changes. This would imply an association between inflammatory features of the adipose tissue and liver fat content. To analyse associations between inflammatory features of the adipose tissue and liver fat content. A cross-sectional study. Twenty-seven obese patients with insulin-treated T2DM were studied. LFAT content was measured by proton magnetic resonance spectroscopy. A subcutaneous (sc) fat biopsy was obtained to determine morphology and protein levels within adipose tissue. In addition to fat cell size, the percentage of macrophages and the presence of crown-like structures (CLSs) within sc fat were assessed by CD68-immunohistochemical staining. Mean LFAT percentage was 11·1 ± 1·7% (range: 0·75-32·9%); 63% of the patients were diagnosed with an elevated LFAT (upper range of normal ≤5·5%). Whereas adipocyte size did not correlate with LFAT, 3 of 4 subjects with CLSs in sc fat had elevated LFAT and the percentage of macrophages present in sc adipose tissue was positively associated with LFAT. Protein concentrations of adiponectin within adipose tissue negatively correlated with LFAT. Adipose tissue protein levels of the key inflammatory adipokine plasminogen activator inhibitor-1 (PAI-1) were positively associated with LFAT. Several pro-inflammatory changes in sc adipose tissue associate with increased LFAT content in obese insulin-treated patients with T2DM. These findings suggest that inflammatory changes at the level of the adipose tissue may drive liver fat accumulation. © 2012 John Wiley & Sons Ltd.

Hydrogels for Engineering of Perfusable Vascular Networks

PubMed Central

Liu, Juan; Zheng, Huaiyuan; Poh, Patrina S. P.; Machens, Hans-Günther; Schilling, Arndt F.

2015-01-01

Hydrogels are commonly used biomaterials for tissue engineering. With their high-water content, good biocompatibility and biodegradability they resemble the natural extracellular environment and have been widely used as scaffolds for 3D cell culture and studies of cell biology. The possible size of such hydrogel constructs with embedded cells is limited by the cellular demand for oxygen and nutrients. For the fabrication of large and complex tissue constructs, vascular structures become necessary within the hydrogels to supply the encapsulated cells. In this review, we discuss the types of hydrogels that are currently used for the fabrication of constructs with embedded vascular networks, the key properties of hydrogels needed for this purpose and current techniques to engineer perfusable vascular structures into these hydrogels. We then discuss directions for future research aimed at engineering of vascularized tissue for implantation. PMID:26184185

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

Young, I.T.; Vanderlaan, M.; Kromhout, L.

Improved early detection of neoplasia by screening of urothelial cells requires an understanding of the features distinguishing normal and neoplastic cell populations. The authors have begun a program of study based upon a rate model system for the controlled observation of early-stage lesions produced by the carcinogen N-butyl-N-(4-hydroxybutyl)- nitrosamine. Cells dissociated directly from normal and malignant urothelium were characterized by conventional cytopathology techniques and by quantitative microscopy (for nuclear texture and nuclear and cytoplasmic size, shape, and stain content) to derive a comprehensive picture of bladder tumor development. By following the changes that occur in the dissociated urothelial cells themore » authors have found that the nuclear area, total nuclear stain, nuclear shape, and the nuclear chromatin change significantly over a 48-wk interval as the lesions progress toward malignancy. 24 references, 10 figures, 1 table.« less

Antibody Binding Alters the Characteristics and Contents of Extracellular Vesicles Released by Histoplasma capsulatum

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

Matos Baltazar, Ludmila; Nakayasu, Ernesto S.; Sobreira, Tiago J. P.

ABSTRACT Histoplasma capsulatumproduces extracellular vesicles containing virulence-associated molecules capable of modulating host machinery, benefiting the pathogen. Treatment ofH. capsulatumcells with monoclonal antibodies (MAbs) can change the outcome of infection in mice. We evaluated the sizes, enzymatic contents, and proteomic profiles of the vesicles released by fungal cells treated with either protective MAb 6B7 (IgG1) or nonprotective MAb 7B6 (IgG2b), both of which bindH. capsulatumheat shock protein 60 (Hsp60). Our results showed that treatment with either MAb was associated with changes in size and vesicle loading. MAb treatments reduced vesicle phosphatase and catalase activities compared to those of vesicles from untreated controls. Wemore » identified 1,125 proteins in vesicles, and 250 of these manifested differences in abundance relative to that of proteins in vesicles isolated from yeast cells exposed to Hsp60-binding MAbs, indicating that surface binding of fungal cells by MAbs modified protein loading in the vesicles. The abundance of upregulated proteins in vesicles upon MAb 7B6 treatment was 44.8% of the protein quantities in vesicles from fungal cells treated with MAb 6B7. Analysis of orthologous proteins previously identified in vesicles from other fungi showed that different ascomycete fungi have similar proteins in their extracellular milieu, many of which are associated with virulence. Our results demonstrate that antibody binding can modulate fungal cell responses, resulting in differential loading of vesicles, which could alter fungal cell susceptibility to host defenses. This finding provides additional evidence that antibody binding modulates microbial physiology and suggests a new function for specific immunoglobulins through alterations of fungal secretion. IMPORTANCEDiverse fungal species release extracellular vesicles, indicating that this is a common pathway for the delivery of molecules to the extracellular space. However, there has been no study reporting the impact of antibody binding to the fungal cell on extracellular vesicle release. In the present work, we observed that treatment ofH. capsulatumcells with Hsp60-binding MAbs significantly changed the size and cargo of extracellular vesicles, as well as the enzymatic activity of certain virulence factors, such as laccase and phosphatase. Furthermore, this finding demonstrates that antibody binding can directly impact protein loading in vesicles and fungal metabolism. Hence, this work presents a new role for antibodies in the modification of fungal physiology.« less

Membrane tension regulates clathrin-coated pit dynamics

NASA Astrophysics Data System (ADS)

Liu, Allen

2014-03-01

Intracellular organization depends on close communication between the extracellular environment and a network of cytoskeleton filaments. The interactions between cytoskeletal filaments and the plasma membrane lead to changes in membrane tension that in turns help regulate biological processes. Endocytosis is thought to be stimulated by low membrane tension and the removal of membrane increases membrane tension. While it is appreciated that the opposing effects of exocytosis and endocytosis have on keeping plasma membrane tension to a set point, it is not clear how membrane tension affects the dynamics of clathrin-coated pits (CCPs), the individual functional units of clathrin-mediated endocytosis. Furthermore, although it was recently shown that actin dynamics counteracts membrane tension during CCP formation, it is not clear what roles plasma membrane tension plays during CCP initiation. Based on the notion that plasma membrane tension is increased when the membrane area increases during cell spreading, we designed micro-patterned surfaces of different sizes to control the cell spreading sizes. Total internal reflection fluorescence microscopy of living cells and high content image analysis were used to quantify the dynamics of CCPs. We found that there is an increased proportion of CCPs with short (<20s) lifetime for cells on larger patterns. Interestingly, cells on larger patterns have higher CCP initiation density, an effect unexpected based on the conventional view of decreasing endocytosis with increasing membrane tension. Furthermore, by analyzing the intensity profiles of CCPs that were longer-lived, we found CCP intensity decreases with increasing cell size, indicating that the CCPs are smaller with increasing membrane tension. Finally, disruption of actin dynamics significantly increased the number of short-lived CCPs, but also decreased CCP initiation rate. Together, our study reveals new mechanistic insights into how plasma membrane tension regulates the dynamics of CCPs.

AtSWEET4, a hexose facilitator, mediates sugar transport to axial sinks and affects plant development

PubMed Central

Liu, Xiaozhu; Zhang, Yan; Yang, Chao; Tian, Zhihong; Li, Jianxiong

2016-01-01

Plants transport photoassimilates from source organs to sink tissues through the phloem translocation pathway. In the transport phloem, sugars that escape from the sieve tubes are released into the apoplasmic space between the sieve element/companion cell complex (SE/CC) and phloem parenchyma cells (PPCs) during the process of long-distance transport. The competition for sugar acquisition between SE/CC and adjoining PPCs is mediated by plasma membrane translocators. YFP-tagged AtSWEET4 protein is localized in the plasma membrane, and PromoterAtSWEET4-GUS analysis showed that AtSWEET4 is expressed in the stele of roots and veins of leaves and flowers. Overexpression of AtSWEET4 in Arabidopsis increases plant size and accumulates more glucose and fructose. By contrast, knock-down of AtSWEET4 by RNA-interference leads to small plant size, reduction in glucose and fructose contents, chlorosis in the leaf vein network, and reduction in chlorophyll content in leaves. Yeast assays demonstrated that AtSWEET4 is able to complement both fructose and glucose transport deficiency. Transgenic plants of AtSWEET4 overexpression exhibit higher freezing tolerance and support more growth of bacterium Pseudomonas syringae pv. phaseolicola NPS3121. We conclude that AtSWEET4 plays an important role in mediating sugar transport in axial tissues during plant growth and development. PMID:27102826

Consequence of a sudden wind event on the dynamics of a coastal phytoplankton community: an insight into specific population growth rates using a single cell high frequency approach

PubMed Central

Dugenne, Mathilde; Thyssen, Melilotus; Nerini, David; Mante, Claude; Poggiale, Jean-Christophe; Garcia, Nicole; Garcia, Fabrice; Grégori, Gérald J.

2014-01-01

Phytoplankton is a key component in marine ecosystems. It is responsible for most of the marine primary production, particularly in eutrophic lagoons, where it frequently blooms. Because they are very sensitive to their environment, the dynamics of these microbial communities has to be observed over different time scales, however, assessment of short term variability is often out of reach of traditional monitoring methods. To overcome these limitations, we set up a Cytosense automated flow cytometer (Cytobuoy b.v.), designed for high frequency monitoring of phytoplankton composition, abundance, cell size, and pigment content, in one of the largest Mediterranean lagoons, the Berre lagoon (South-Eastern France). During October 2011, it recorded the cell optical properties of 12 groups of pico-, nano-, and microphytoplankton. Daily variations in the cluster optical properties were consistent with individual changes observed using microscopic imaging, during the cell cycle. We therefore used an adaptation of the size-structured matrix population model, developed by Sosik et al. (2003) to process the single cell analysis of the clusters and estimate the division rates of 2 dinoflagellate populations before, during, and after a strong wind event. The increase in the estimated in situ daily cluster growth rates suggest that physiological changes in the cells can prevail over the response of abundance. PMID:25309523

Effects of perfluorinated chemicals on adipocyte development ...

EPA Pesticide Factsheets

Obesity is a growing concern in the US population. Current interest is high in the role played by environmental factors called obesogens that may contribute to obesity through developmental exposure. One class of potential obesogens is the family of perfluorinated chemicals used as surfactants in a variety of industrial applications. Given the importance of understanding the role these compounds play in lipid homeostasis we used pre-adipocyte 3T3-L1 mouse fibroblast cells (Zen-Bio, RTP NC) to study their effects on adipogenesis and lipid accumulation. These cells differentiate into adipocytes accumulating large lipid droplets. Cultures were treated with perfluorooctanoic acid (PFOA) (1-200uM), perfluorononanoic acid (PFNA) (5-lOOuM), perfluorooctane sulfonate (PFOS) (5O-300uM), and perfluorohexane sulfonate (PFHxS) (40- 250uM). Cell size number, and lipid content were assessed using morphomeiric analysis. All four compounds decreased cell size compared to control, and PFNA was most potent, in terms of lowest observed effect concentration (LOEC), whereas PFOA was least potent. Cell number increased for all perfluorinated chemicals tested, most potently for PFNA and least for PFOS. Interestingly, average lipid area per cell for all four chemicals decreased compared to control, but PFOS and PFHxS had increased total lipid area. Additionally, significant increases in total triglyceride were noted for all compounds compared to controls. PFOA and PFNA increased trigly

Compositional and structural properties of pulsed laser-deposited ZnS:Cr films

NASA Astrophysics Data System (ADS)

Nematollahi, Mohammadreza; Yang, Xiaodong; Seim, Eivind; Vullum, Per Erik; Holmestad, Randi; Gibson, Ursula J.; Reenaas, Turid W.

2016-02-01

We present the properties of Cr-doped zinc sulfide (ZnS:Cr) films deposited on Si(100) by pulsed laser deposition. The films are studied for solar cell applications, and to obtain a high absorption, a high Cr content (2.0-5.0 at.%) is used. It is determined by energy-dispersive X-ray spectroscopy that Cr is relatively uniformly distributed, and that local Cr increases correspond to Zn decreases. The results indicate that most Cr atoms substitute Zn sites. Consistently, electron energy loss and X-ray photoelectron spectroscopy showed that the films contain mainly Cr2+ ions. Structural analysis showed that the films are polycrystalline and textured. The films with ~4 % Cr are mainly grown along the hexagonal [001] direction in wurtzite phase. The average lateral grain size decreases with increasing Cr content, and at a given Cr content, increases with increasing growth temperature.

Development of Chitosan-based Dry Powder Inhalation System of Cisplatin for Lung Cancer

PubMed Central

Singh, D. J.; Lohade, A. A.; Parmar, J. J.; Hegde, Darshana D.; Soni, P.; Samad, A.; Menon, Mala D.

2012-01-01

Cisplatin, a platinum compound, exerts its cytotoxic effects by coordinating to DNA where it inhibits both replication and transcription, and induces programmed cell death. It is used in the treatment of non-small cell lung cancer. In the present study, an attempt was made to achieve better treatment of lung cancer by direct lung delivery of cisplatin microparticulate systems, which helps to localize the drug in the lungs, and also provide sustained action. Cisplatin-loaded chitosan microspheres were prepared by emulsification and ionotropic gelation method, and characterized for drug content, particle size, densities, flow properties, moisture content, and surface topography by SEM and in vitro drug release was evaluated in simulated lung fluid at 37° at pH 7.4. The respirable or fine particle fraction (FPF) was determined by using twin stage impinger (TSI). Further stability evaluation of cisplatin-loaded DPI systems was carried out at 25°/60% RH and at 40°/75% RH. PMID:23798777

The Effect of Sericin from Various Extraction Methods on Cell Viability and Collagen Production

PubMed Central

Aramwit, Pornanong; Kanokpanont, Sorada; Nakpheng, Titpawan; Srichana, Teerapol

2010-01-01

Silk sericin (SS) can accelerate cell proliferation and attachment; however, SS can be extracted by various methods, which result in SS exhibiting different physical and biological properties. We found that SS produced from various extraction methods has different molecular weights, zeta potential, particle size and amino acid content. The MTT assay indicated that SS from all extraction methods had no toxicity to mouse fibroblast cells at concentrations up to 40 μg/mL after 24 h incubation, but SS obtained from some extraction methods can be toxic at higher concentrations. Heat-degraded SS was the least toxic to cells and activated the highest collagen production, while urea-extracted SS showed the lowest cell viability and collagen production. SS from urea extraction was severely harmful to cells at concentrations higher than 100 μg/mL. SS from all extraction methods could still promote collagen production in a concentration-dependent manner, even at high concentrations that are toxic to cells. PMID:20559510

Processing of Microalgae: Acoustic Cavitation and Hydrothermal Conversion

NASA Astrophysics Data System (ADS)

Greenly, Justin Michael

The production of energy dense fuels from renewable algal biomass feedstocks -- if sustainably developed at a sufficiently large scale -- may reduce the consumption of petroleum from fossil fuels and provide many environmental benefits. Achieving economic feasibility has several technical engineering challenges that arise from dilute concentration of growing algae in aqueous media, small cell sizes, and durable cell walls. For microalgae to be a sustainable source of biofuels and co-products, efficient fractionation and conversion of the cellular contents is necessary. Research was carried out to address two processing options for efficient microalgae biofuel production: 1. Ultrasonic cavitation for cell disruption and 2. Hydrothermal conversion of a model algal triglyceride. 1. Ultrasonic cell disruption, which relies on cavitating bubbles in the suspension to produce damaging shock waves, was investigated experimentally over a range of concentrations and species types. A few seconds of high intensity sonication at fixed frequency yielded significant cell disruption, even for the more durable cells. At longer exposure times, effectiveness was seen to decline and was attributed, using acoustic measurements, to ultrasonic power attenuation in the ensuing cloud of cavitating bubbles. Processing at higher cell concentrations slowed cell disintegration marginally, but increased the effectiveness of dissipating ultrasonic energy. A theoretical study effectively predicted optimal conditions for a variety of parameters that were inaccessible in this experimental investigation. In that study, single bubble collapse was modeled to identify operating conditions that would increase cavitation, and thus cell disruption. Simulations were conducted by varying frequency and pressure amplitude of the ultrasound wave, and initial bubble size. The simulation results indicated that low frequency, high sound wave amplitudes, and small initial bubble size generate the highest shock wave pressures. 2. Hydrolysis of a pure model triglyceride compound was experimentally examined for the first time at hydrothermal conditions -- from 225 to 300°C. Lipid product composition assessed by GC-FID was compared to previous studies with mixed vegetable oils and used to develop a kinetic model for this oil phase reaction.

Bioreactors to Influence Stem Cell Fate: Augmentation of Mesenchymal Stem Cell Signaling Pathways via Dynamic Culture Systems

PubMed Central

Yeatts, Andrew B.; Choquette, Daniel T.; Fisher, John P.

2012-01-01

Background Mesenchymal stem cells (MSCs) are a promising cell source for bone and cartilage tissue engineering as they can be easily isolated from the body and differentiated into osteoblasts and chondrocytes. A cell based tissue engineering strategy using MSCs often involves the culture of these cells on three-dimensional scaffolds; however the size of these scaffolds and the cell population they can support can be restricted in traditional static culture. Thus dynamic culture in bioreactor systems provides a promising means to culture and differentiate MSCs in vitro. Scope of Review This review seeks to characterize key MSC differentiation signaling pathways and provides evidence as to how dynamic culture is augmenting these pathways. Following an overview of dynamic culture systems, discussion will be provided on how these systems can effectively modify and maintain important culture parameters including oxygen content and shear stress. Literature is reviewed for both a highlight of key signaling pathways and evidence for regulation of these signaling pathways via dynamic culture systems. Major Conclusions The ability to understand how these culture systems are affecting MSC signaling pathways could lead to a shear or oxygen regime to direct stem cell differentiation. In this way the efficacy of in vitro culture and differentiation of MSCs on three-dimensional scaffolds could be greatly increased. General Significance Bioreactor systems have the ability to control many key differentiation stimuli including mechanical stress and oxygen content. The further integration of cell signaling investigations within dynamic culture systems will lead to a quicker realization of the promise of tissue engineering and regenerative medicine. PMID:22705676

Engineering temporal accumulation of a low recalcitrance polysaccharide leads to increased C6 sugar content in plant cell walls

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

Vega-Sánchez, Miguel E.; Loqué, Dominique; Lao, Jeemeng

Reduced cell wall recalcitrance and increased C6 monosaccharide content are desirable traits for future biofuel crops, as long as these biomass modifications do not significantly alter normal growth and development. Mixed-linkage glucan (MLG), a cell wall polysaccharide only present in grasses and related species among flowering plants, is comprised of glucose monomers linked by both β-1,3 and β-1,4 bonds. Previous data have shown that constitutive production of MLG in barley (Hordeum vulgare) severely compromises growth and development. Here, we used spatio-temporal strategies to engineer Arabidopsis thaliana plants to accumulate significant amounts of MLG in the cell wall by expressing themore » rice CslF6 MLG synthase using secondary cell wall and senescence-associated promoters. Results using secondary wall promoters were suboptimal. When the rice MLG synthase was expressed under the control of a senescence-associated promoter, we obtained up to four times more glucose in the matrix cell wall fraction and up to a 42% increase in saccharification compared to control lines. Importantly, these plants grew and developed normally. The induction of MLG deposition at senescence correlated with an increase of gluconic acid in cell wall extracts of transgenic plants in contrast to the other approaches presented in this study. MLG produced in Arabidopsis has an altered structure compared to the grass glucan, which likely affects its solubility, while its molecular size is unaffected. The induction of cell wall polysaccharide biosynthesis in senescing tissues offers a novel engineering alternative to enhance cell wall properties of lignocellulosic biofuel crops.« less

Dynamics of Marine Microbial Metabolism and Physiology at Station ALOHA

NASA Astrophysics Data System (ADS)

Casey, John R.

Marine microbial communities influence global biogeochemical cycles by coupling the transduction of free energy to the transformation of Earth's essential bio-elements: H, C, N, O, P, and S. The web of interactions between these processes is extraordinarily complex, though fundamental physical and thermodynamic principles should describe its dynamics. In this collection of 5 studies, aspects of the complexity of marine microbial metabolism and physiology were investigated as they interact with biogeochemical cycles and direct the flow of energy within the Station ALOHA surface layer microbial community. In Chapter 1, and at the broadest level of complexity discussed, a method to relate cell size to metabolic activity was developed to evaluate allometric power laws at fine scales within picoplankton populations. Although size was predictive of metabolic rates, within-population power laws deviated from the broader size spectrum, suggesting metabolic diversity as a key determinant of microbial activity. In Chapter 2, a set of guidelines was proposed by which organic substrates are selected and utilized by the heterotrophic community based on their nitrogen content, carbon content, and energy content. A hierarchical experimental design suggested that the heterotrophic microbial community prefers high nitrogen content but low energy density substrates, while carbon content was not important. In Chapter 3, a closer look at the light-dependent dynamics of growth on a single organic substrate, glycolate, suggested that growth yields were improved by photoheterotrophy. The remaining chapters were based on the development of a genome-scale metabolic network reconstruction of the cyanobacterium Prochlorococcus to probe its metabolic capabilities and quantify metabolic fluxes. Findings described in Chapter 4 pointed to evolution of the Prochlorococcus metabolic network to optimize growth at low phosphate concentrations. Finally, in Chapter 5 and at the finest scale of complexity, a method was developed to predict hourly changes in both physiology and metabolic fluxes in Prochlorococcus by incorporating gene expression time-series data within the metabolic network model. Growth rates predicted by this method more closely matched experimental data, and diel changes in elemental composition and the energy content of biomass were predicted. Collectively, these studies identify and quantify the potential impact of variations in metabolic and physiological traits on the melee of microbial community interactions.

Reassessment of genome size in turtle and crocodile based on chromosome measurement by flow karyotyping: close similarity to chicken

PubMed Central

Kasai, Fumio; O'Brien, Patricia C. M.; Ferguson-Smith, Malcolm A.

2012-01-01

The genome size in turtles and crocodiles is thought to be much larger than the 1.2 Gb of the chicken (Gallus gallus domesticus, GGA), according to the animal genome size database. However, GGA macrochromosomes show extensive homology in the karyotypes of the red eared slider (Trachemys scripta elegans, TSC) and the Nile crocodile (Crocodylus niloticus, CNI), and bird and reptile genomes have been highly conserved during evolution. In this study, size and GC content of all chromosomes are measured from the flow karyotypes of GGA, TSC and CNI. Genome sizes estimated from the total chromosome size demonstrate that TSC and CNI are 1.21 Gb and 1.29 Gb, respectively. This refines previous overestimations and reveals similar genome sizes in chicken, turtle and crocodile. Analysis of chromosome GC content in each of these three species shows a higher GC content in smaller chromosomes than in larger chromosomes. This contrasts with mammals and squamates in which GC content does not correlate with chromosome size. These data suggest that a common ancestor of birds, turtles and crocodiles had a small genome size and a chromosomal size-dependent GC bias, distinct from the squamate lineage. PMID:22491763

Inhibitory effects of Zanthoxylum rhoifolium Lam. (Rutaceae) against the infection and infectivity of macrophages by Leishmania amazonensis.

PubMed

Melo, Bernardo; Leitão, Joseana M S R; Oliveira, Luciano G C; Santos, Sérgio E M; Carneiro, Sabrina M P; Rodrigues, Klinger A F; Chaves, Mariana H; Arcanjo, Daniel D R; Carvalho, Fernando A A

2016-01-01

Zanthoxylum rhoifolium Lam. (Rutaceae) has been traditionally used in the treatment of microbial infections and parasitic diseases. In the present study, the antileishmanial effect induced by the ethanol extract of stem barks from Z. rhoifolium (ZR-EEtOH) and its n-hexane fraction (ZR-FHEX) on infection and infectivity of murine macrophages by promastigote forms of Leishmania amazonensis were investigated. In different set of experiments, macrophages or promastigotes were pretreated with ZR-EEtOH or ZR-FHEX at non-lethal concentrations for 24 hours, and then macrophages were submitted to infection by promastigotes. Moreover, their effects on activation of macrophages, as well as on the DNA content, size and number of promastigotes by flow cytometry were also evaluated. The infection rate and the number of internalized amastigote forms were markedly decreased after pretreatment of macrophages or promastigotes when compared with non-treated cells. The increase in phagocytic capability and nitrite content was also observed. Furthermore, the decrease of DNA content, size and number of promastigotes was also observed. In conclusion, ZR-EEtOH and ZR-FHEX promoted a markedly significant antileishmanial effect and reduction of infection of macrophages, probably underlying defense mechanisms activation in macrophages. These findings reinforce the potential application of Z. rhoifolium in the treatment of leishmaniasis.

Detection and capture of single circulating melanoma cells using photoacoustic flowmetry

NASA Astrophysics Data System (ADS)

O'Brien, Christine; Mosley, Jeffrey; Goldschmidt, Benjamin S.; Viator, John A.

2010-02-01

Photoacoustic flowmetry has been used to detect single circulating melanoma cells in vitro. Circulating melanoma cells are those cells that travel in the blood and lymph systems to create secondary tumors and are the hallmark of metastasis. This technique involves taking blood samples from patients, separating the white blood and melanoma cells from whole blood and irradiating them with a pulsed laser in a flowmetry set up. Rapid, visible wavelength laser pulses on the order of 5 ns can induce photoacoustic waves in melanoma cells due to their melanin content, while surrounding white blood cells remain acoustically passive. We have developed a system that identifies rare melanoma cells and captures them in 50 microliter volumes using suction applied near the photoacoustic detection chamber. The 50 microliter sample is then diluted and the experiment is repeated using the new sample until only a melanoma cell remains. We have tested this system on dyed microspheres ranging in size from 300 to 500 microns. Capture of circulating melanoma cells may provide the opportunity to study metastatic cells for basic understanding of the spread of cancer and to optimize patient specific therapies.

Food photography II: use of food photographs for estimating portion size and the nutrient content of meals.

PubMed

Nelson, M; Atkinson, M; Darbyshire, S

1996-07-01

The aim of the present study was to determine the errors in the conceptualization of portion size using photographs. Male and female volunteers aged 18-90 years (n 136) from a wide variety of social and occupational backgrounds completed 602 assessments of portion size in relation to food photographs. Subjects served themselves between four and six foods at one meal (breakfast, lunch or dinner). Portion sizes were weighed by the investigators at the time of serving, and any waste was weighed at the end of the meal. Within 5 min of the end of the meal, subjects were shown photographs depicting each of the foods just consumed. For each food there were eight photographs showing portion sizes in equal increments from the 5th to the 95th centile of the distribution of portion weights observed in The Dietary and Nutritional Survey of British Adults (Gregory et al. 1990). Subjects were asked to indicate on a visual analogue scale the size of the portion consumed in relation to the eight photographs. The nutrient contents of meals were estimated from food composition tables. There were large variations in the estimation of portion sizes from photographs. Butter and margarine portion sizes tended to be substantially overestimated. In general, small portion sizes tended to be overestimated, and large portion sizes underestimated. Older subjects overestimated portion size more often than younger subjects. Excluding butter and margarine, the nutrient content of meals based on estimated portion sizes was on average within +/- 7% of the nutrient content based on the amounts consumed, except for vitamin C (21% overestimate), and for subjects over 65 years (15-20% overestimate for energy and fat). In subjects whose BMI was less than 25 kg/m2, the energy and fat contents of meals calculated from food composition tables and based on estimated portion size (excluding butter and margarine) were 5-10% greater than the nutrient content calculated using actual portion size, but for those with BMI 30 kg/m2 or over, the calculated energy and fat contents were underestimated by 2-5%. The correlation of the nutrient content of meals based on actual or estimated portion sizes ranged from 0-84 to 0-96. For energy and eight nutrients, between 69 and 89% subjects were correctly classified into thirds of the distribution of intake using estimated portion size compared with intakes based on actual portion sizes. When 'average' portion sizes (the average weight of each of the foods which the subjects had served themselves) were used in place of the estimates based on photographs, the number of subjects correctly classified fell to between 60 and 79%. We report for the first time the error associated with conceptualization and the nutrient content of meals when using photographs to estimate food portion size. We conclude that photographs depicting a range of portion sizes are a useful aid to the estimation of portion size. Misclassification of subjects according to their nutrient intake from one meal is reduced when photographs are used to estimate portion size, compared with the use of average portions. Age, sex, BMI and portion size are all potentially important confounders when estimating food consumption or nutrient intake using photographs.

Variations in serving sizes of Australian snack foods and confectionery.

PubMed

Watson, Wendy L; Kury, Alexandra; Wellard, Lyndal; Hughes, Clare; Dunford, Elizabeth; Chapman, Kathy

2016-01-01

This study examined the serving size and energy content per serving of Australian packaged snack foods and confectionery products. Nutrition Information Panel data for 23 sub-categories of packaged snack foods (n = 3481) were extracted from The George Institute for Global Health's 2013 branded food composition database. Variations in serving size and energy content per serving were examined. Energy contents per serving were compared to recommendations in the Australian Dietary Guidelines. Serving sizes varied within and between snack food categories. Mean energy content per serving varied from 320 kJ to 899 kJ. More energy per serving than the recommended 600 kJ was displayed by 22% (n = 539) of snack foods classified in the Australian Dietary Guidelines as discretionary foods. The recommendation for energy content per serving was exceeded in 60% (n = 635) of snack foods from the Five Food Groups. Only 37% (n = 377) of confectionery products displayed the industry-agreed serving size of 25 g. Energy content per serving of many packaged snack foods do not align with the Australian Dietary Guidelines and the industry agreed serving size has not been taken up widely within the confectionery category. Given the inconsistencies in serving sizes, featuring serving size in front-of-pack information may hinder the objective of a clear and simple nutrition message. Messaging to help consumers make healthier choices should consider the variation in serving sizes on packaged snack foods. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impairment of glucose-induced insulin secretion in human pancreatic islets transplanted to diabetic nude mice.

PubMed

Jansson, L; Eizirik, D L; Pipeleers, D G; Borg, L A; Hellerström, C; Andersson, A

1995-08-01

Hyperglycemia-induced beta-cell dysfunction may be an important component in the pathogenesis of non-insulin-dependent diabetes mellitus. However, most available data in this field were obtained from rodent islets. To investigate the relevance of this hypothesis for human beta-cells in vivo, human pancreatic islets were transplanted under the renal capsule of nude mice. Experimental groups were chosen so that grafted islets were exposed to either hyper- or normoglycemia or combinations of these for 4 or 6 wk. Grafts of normoglycemic recipients responded with an increased insulin release to a glucose stimulus during perfusion, whereas grafts of hyperglycemic recipients failed to respond to glucose. The insulin content of the grafts in the latter groups was only 10% of those observed in controls. Recipients initially hyperglycemic (4 wk), followed by 2 wk of normoglycemia regained a normal graft insulin content, but a decreased insulin response to glucose remained. No ultrastructural signs of beta-cell damage were observed, with the exception of increased glycogen deposits in animals hyperglycemic at the time of killing. It is concluded that prolonged exposure to a diabetic environment induces a long-term secretory defect in human beta-cells, which is not dependent on the size of the islet insulin stores.

Impairment of glucose-induced insulin secretion in human pancreatic islets transplanted to diabetic nude mice.

PubMed Central

Jansson, L; Eizirik, D L; Pipeleers, D G; Borg, L A; Hellerström, C; Andersson, A

1995-01-01

Hyperglycemia-induced beta-cell dysfunction may be an important component in the pathogenesis of non-insulin-dependent diabetes mellitus. However, most available data in this field were obtained from rodent islets. To investigate the relevance of this hypothesis for human beta-cells in vivo, human pancreatic islets were transplanted under the renal capsule of nude mice. Experimental groups were chosen so that grafted islets were exposed to either hyper- or normoglycemia or combinations of these for 4 or 6 wk. Grafts of normoglycemic recipients responded with an increased insulin release to a glucose stimulus during perfusion, whereas grafts of hyperglycemic recipients failed to respond to glucose. The insulin content of the grafts in the latter groups was only 10% of those observed in controls. Recipients initially hyperglycemic (4 wk), followed by 2 wk of normoglycemia regained a normal graft insulin content, but a decreased insulin response to glucose remained. No ultrastructural signs of beta-cell damage were observed, with the exception of increased glycogen deposits in animals hyperglycemic at the time of killing. It is concluded that prolonged exposure to a diabetic environment induces a long-term secretory defect in human beta-cells, which is not dependent on the size of the islet insulin stores. Images PMID:7635965

Evolution of genome size and genomic GC content in carnivorous holokinetics (Droseraceae).

PubMed

Veleba, Adam; Šmarda, Petr; Zedek, František; Horová, Lucie; Šmerda, Jakub; Bureš, Petr

2017-02-01

Studies in the carnivorous family Lentibulariaceae in the last years resulted in the discovery of the smallest plant genomes and an unusual pattern of genomic GC content evolution. However, scarcity of genomic data in other carnivorous clades still prevents a generalization of the observed patterns. Here the aim was to fill this gap by mapping genome evolution in the second largest carnivorous family, Droseraceae, where this evolution may be affected by chromosomal holokinetism in Drosera METHODS: The genome size and genomic GC content of 71 Droseraceae species were measured by flow cytometry. A dated phylogeny was constructed, and the evolution of both genomic parameters and their relationship to species climatic niches were tested using phylogeny-based statistics. The 2C genome size of Droseraceae varied between 488 and 10 927 Mbp, and the GC content ranged between 37·1 and 44·7 %. The genome sizes and genomic GC content of carnivorous and holocentric species did not differ from those of their non-carnivorous and monocentric relatives. The genomic GC content positively correlated with genome size and annual temperature fluctuations. The genome size and chromosome numbers were inversely correlated in the Australian clade of Drosera CONCLUSIONS: Our results indicate that neither carnivory (nutrient scarcity) nor the holokinetism have a prominent effect on size and DNA base composition of Droseraceae genomes. However, the holokinetic drive seems to affect karyotype evolution in one of the major clades of Drosera Our survey confirmed that the evolution of GC content is tightly connected with the evolution of genome size and also with environmental conditions. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Computed tomography-guided tissue engineering of upper airway cartilage.

PubMed

Brown, Bryan N; Siebenlist, Nicholas J; Cheetham, Jonathan; Ducharme, Norm G; Rawlinson, Jeremy J; Bonassar, Lawrence J

2014-06-01

Normal laryngeal function has a large impact on quality of life, and dysfunction can be life threatening. In general, airway obstructions arise from a reduction in neuromuscular function or a decrease in mechanical stiffness of the structures of the upper airway. These reductions decrease the ability of the airway to resist inspiratory or expiratory pressures, causing laryngeal collapse. We propose to restore airway patency through methods that replace damaged tissue and improve the stiffness of airway structures. A number of recent studies have utilized image-guided approaches to create cell-seeded constructs that reproduce the shape and size of the tissue of interest with high geometric fidelity. The objective of the present study was to establish a tissue engineering approach to the creation of viable constructs that approximate the shape and size of equine airway structures, in particular the epiglottis. Computed tomography images were used to create three-dimensional computer models of the cartilaginous structures of the larynx. Anatomically shaped injection molds were created from the three-dimensional models and were seeded with bovine auricular chondrocytes that were suspended within alginate before static culture. Constructs were then cultured for approximately 4 weeks post-seeding and evaluated for biochemical content, biomechanical properties, and histologic architecture. Results showed that the three-dimensional molded constructs had the approximate size and shape of the equine epiglottis and that it is possible to seed such constructs while maintaining 75%+ cell viability. Extracellular matrix content was observed to increase with time in culture and was accompanied by an increase in the mechanical stiffness of the construct. If successful, such an approach may represent a significant improvement on the currently available treatments for damaged airway cartilage and may provide clinical options for replacement of damaged tissue during treatment of obstructive airway disease.

High content analysis provides mechanistic insights on the pathways of toxicity induced by amine-modified polystyrene nanoparticles.

PubMed

Anguissola, Sergio; Garry, David; Salvati, Anna; O'Brien, Peter J; Dawson, Kenneth A

2014-01-01

The fast-paced development of nanotechnology needs the support of effective safety testing. We have developed a screening platform measuring simultaneously several cellular parameters for exposure to various concentrations of nanoparticles (NPs). Cell lines representative of different organ cell types, including lung, endothelium, liver, kidney, macrophages, glia, and neuronal cells were exposed to 50 nm amine-modified polystyrene (PS-NH2) NPs previously reported to induce apoptosis and to 50 nm sulphonated and carboxyl-modified polystyrene NPs that were reported to be silent. All cell lines apart from Raw 264.7 executed apoptosis in response to PS-NH2 NPs, showing specific sequences of EC50 thresholds; lysosomal acidification was the most sensitive parameter. Loss of mitochondrial membrane potential and plasma membrane integrity measured by High Content Analysis resulted comparably sensitive to the equivalent OECD-recommended assays, allowing increased output. Analysis of the acidic compartments revealed good cerrelation between size/fluorescence intensity and dose of PS-NH2 NPs applied; moreover steatosis and phospholipidosis were observed, consistent with the lysosomal alterations revealed by Lysotracker green; similar responses were observed when comparing astrocytoma cells with primary astrocytes. We have established a platform providing mechanistic insights on the response to exposure to nanoparticles. Such platform holds great potential for in vitro screening of nanomaterials in highthroughput format.

Glucosylated polyethylenimine as a tumor-targeting gene carrier.

PubMed

Park, In-Kyu; Cook, Seung-Eun; Kim, You-Kyoung; Kim, Hyun-Woo; Cho, Myung-Haing; Jeong, Hwan-Jeong; Kim, Eun-Mi; Nah, Jae-Woon; Bom, Hee-Seung; Cho, Chong-Su

2005-11-01

Glucosylated polyethylenimine (GPEI) was synthesized as a tumor-targeting gene carrier through facilitative glucose metabolism by tumor glucose transporter. Particle sizes of GPEI/DNA complex increased in proportion to glucose content of GPEI, whereas surface charge of the complex was not dependent on glucosylation, partially due to inefficient shielding of the short hydrophilic group introduced. GPEI with higher glucosylation (36 mol-%) had no cytotoxic effect on cells even at polymer concentrations higher than 200 microg/mL. Compared to unglucosylated PEI, glucosylation induced less than one-order decrease of transfection efficiency. Transfection of GPEI/DNA complex into tumor cells possibly occurred through specific interaction between glucose-related cell receptors and glucose moiety of GPEI. Gamma imaging technique revealed GPEI/DNA complex was distributed in liver, spleen, and tumors.

A scanning acoustic microscope discriminates cancer cells in fluid

NASA Astrophysics Data System (ADS)

Miura, Katsutoshi; Yamamoto, Seiji

2015-10-01

Scanning acoustic microscopy (SAM) discriminates lesions in sections by assessing the speed of sound (SOS) or attenuation of sound (AOS) through tissues within a few minutes without staining; however, its clinical use in cytological diagnosis is unknown. We applied a thin layer preparation method to observe benign and malignant effusions using SAM. Although SAM is inferior in detecting nuclear features than light microscopy, it can differentiate malignant from benign cells using the higher SOS and AOS values and large irregular cell clusters that are typical features of carcinomas. Moreover, each single malignant cell exhibits characteristic cytoplasmic features such as a large size, irregular borders and secretory or cytoskeletal content. By adjusting the observation range, malignant cells are differentiated from benign cells easily using SAM. Subtle changes in the functional and structural heterogeneity of tumour cells were pursuable with a different digital data of SAM. SAM can be a useful tool for screening malignant cells in effusions before light microscopic observation. Higher AOS values in malignant cells compared with those of benign cells support the feasibility of a novel sonodynamic therapy for malignant effusions.

Calbindin-immunoreactive cells in the fish enteric nervous system.

PubMed

Olsson, Catharina

2011-01-20

Calbindin is present in a large proportion of the intrinsic primary afferent neurons (IPANs) in the mammalian gut. Little is known about either calbindin or IPANs in fish. In the present study, calbindin immunoreactivity was investigated in the enteric nervous system of the teleost shorthorn sculpin (Myoxocephalus scorpius). Calbindin-immunoreactive nerve cell bodies and nerve fibres were present in all the gut regions except the cardiac stomach. The highest proportion was found in the proximal intestine where calbindin-immunoreactive cells constituted 59±6% (N=3) of the total Hu C/D-immunoreactive myenteric nerve cell population. In other regions, calbindin-immunoreactive cells constituted around 30% of the total population. The cells were generally multipolar with one long axon. The size distribution differed significantly between calbindin-positive and calbindin-negative cells in each of the three animals examined. Calbindin-positive neurons in the proximal intestine had a mean cross-sectional soma area of 163±73μm(2) (n=183 cells) while calbindin-negative cells were 348±221μm(2) (n=127 cells). Calbindin immunoreactivity colocalised to a large extent with serotonin immunoreactivity, but not with choline acetyltransferase (ChAT)-immunoreactivity. Thus, the calbindin-immunoreactive nerve cell population in the shorthorn sculpin gut seems to constitute a homogenous subpopulation of the enteric neurons, at least when considering the size and content of some transmitters. Whether markers other than serotonin and ChAT would differentiate the population remains to be tested. In conclusion, the calbindin-immunoreactive cells in the sculpin differ from mammalian IPANs with regard to several parameters and future functional studies could hopefully add information about the role of this large group of cells in the fish enteric nervous system. Copyright © 2010 Elsevier B.V. All rights reserved.

A microfluidic flow-through device for high throughput electrical lysis of bacterial cells based on continuous dc voltage.

PubMed

Wang, Hsiang-Yu; Bhunia, Arun K; Lu, Chang

2006-12-15

Interest in electrical lysis of biological cells on a microfludic platform has increased because it allows for the rapid recovery of intracellular contents without introducing lytic agents. In this study we demonstrated a simple microfluidic flow-through device which lysed Escherichia coli cells under a continuous dc voltage. The E. coli cells had previously been modified to express green fluorescent protein (GFP). In our design, the cell lysis only happened in a defined section of a microfluidic channel due to the local field amplification by geometric modification. The geometric modification also effectively decreased the required voltage for lysis by several folds. We found that local field strength of 1000-1500 V/cm was required for nearly 100% cell death. This threshold field strength was considerably lower than the value reported in the literature, possibly due to the longer duration of the field [Lee, S.W., Tai, Y.C., 1999. Sens. Actuators A: Phys. 73, 74-79]. Cell lysis was detected by both plate count and fluorescence spectroscopy. The cell membrane was completely disintegrated in the lysis section of the microfluidic device, when the field strength was higher than 2000 V/cm. The devices were fabricated using low-cost soft lithography with channel widths considerably larger than the cell size to avoid clogging and ensure stable performance. Our tool will be ideal for high throughput processing of bacterial cells for chemical analysis of intracellular contents such as DNA and proteins. The application of continuous dc voltage greatly simplified the instrumentation compared to devices using electrical pulses for similar purposes. In principle, the same approach can also be applied for lysis of mammalian cells and electroporative transfection.

Alternate pathogenesis of systemic neoplasia in the bivalve mollusc Mytilus.

PubMed

Moore, J D; Elston, R A; Drum, A S; Wilkinson, M T

1991-09-01

The proliferative disease systemic neoplasia, also termed hemic neoplasia or disseminated sarcoma, was studied in four Puget Sound, Washington populations of the bay mussel (Mytilus sp.). Using flow cytometric measurement of DAPI-stained cells withdrawn from the hemolymph, DNA content frequency histograms were generated for 73 individuals affected by the disease. The cells manifesting systemic neoplasia were found to exist as either of two separate types, characterized by G0G1 phase nuclear DNA contents of either approximately 4.9 x haploid (pentaploid form) or approximately 3.8 x haploid (tetraploid form). The two disease forms were found to coexist in all four mussel populations sampled, with overall relative prevalences of 66% pentaploid form, 29% tetraploid form, and 5% exhibiting both disease forms simultaneously. These findings represent the first unequivocal demonstration of multiple cell types in a bivalve neoplasia. The two forms appear to represent separate pathogenetic processes rather than sequential stages of a single pathogenesis. Two cell cycling parameters associated with proliferative activity were employed to compare the alternate forms: (i) the percentage of cells assigned to the DNA Synthesis (S) phase of the neoplastic cell cycle, and (ii) the proportion of neoplastic cell mitotic figures in hemocytological preparations. Mean values for both parameters were significantly higher for mussels with the tetraploid form of the disease, suggesting a higher rate of proliferation relative to the pentaploid form. Qualitatively, cells of the tetraploid form contained slightly lower nuclear and cytoplasmic volumes compared to those of the pentaploid form. An observed wide variation in neoplastic cell nuclear size within either disease form may reflect the distribution of cells in the G0G1, S, and G2M phases of the cell cycle. Potential etiologic relationships between the two forms are discussed.

β-Cell-specific pyruvate dehydrogenase deficiency impairs glucose-stimulated insulin secretion

PubMed Central

Srinivasan, Malathi; Choi, Cheol S.; Ghoshal, Pushpankur; Pliss, Lioudmila; Pandya, Jignesh D.; Hill, David; Cline, Gary

2010-01-01

Glucose-stimulated insulin secretion (GSIS) by β-cells requires the generation of ATP from oxidation of pyruvate as well as generation of coupling factors involving three different pyruvate cycling shuttles. The roles of several key enzymes involved in pyruvate cycling in β-cells have been documented using isolated islets and β-cell clonal lines. To investigate the role of the pyruvate dehydrogenase (PDH) complex (PDC) in GSIS, a murine model of β-cell-specific PDH deficiency (β-PDHKO) was created. Pancreatic insulin content was decreased in 1-day-old β-PDHKO male pups and adult male mice. The plasma insulin levels were decreased and blood glucose levels increased in β-PDHKO male mice from neonatal life onward. GSIS was reduced in isolated islets from β-PDHKO male mice with about 50% reduction in PDC activity. Impairment in a glucose tolerance test and in vivo insulin secretion during hyperglycemic clamp was evident in β-PDHKO adults. No change in the number or size of islets was found in pancreata from 4-wk-old β-PDHKO male mice. However, an increase in the mean size of individual β-cells in islets of these mice was observed. These findings show a key role of PDC in GSIS by pyruvate oxidation. This β-PDHKO mouse model represents the first mouse model in which a mitochondrial oxidative enzyme deletion by gene knockout has been employed to demonstrate an altered GSIS by β-cells. PMID:20841503

Nitrogen availability of grape juice limits killer yeast growth and fermentation activity during mixed-culture fermentation with sensitive commercial yeast strains.

PubMed Central

Medina, K; Carrau, F M; Gioia, O; Bracesco, N

1997-01-01

The competition between selected or commercial killer strains of type K2 and sensitive commercial strains of Saccharomyces cerevisiae was studied under various conditions in sterile grape juice fermentations. The focus of this study was the effect of yeast inoculation levels and the role of assimilable nitrogen nutrition on killer activity. A study of the consumption of free amino nitrogen (FAN) by pure and mixed cultures of killer and sensitive cells showed no differences between the profiles of nitrogen assimilation in all cases, and FAN was practically depleted in the first 2 days of fermentation. The effect of the addition of assimilable nitrogen and the size of inoculum was examined in mixed killer and sensitive strain competitions. Stuck and sluggish wine fermentations were observed to depend on nitrogen availability when the ratio of killer to sensitive cells was low (1:10 to 1:100). A relationship between the initial assimilable nitrogen content of must and the proportion of killer cells during fermentation was shown. An indirect relationship was found between inoculum size and the percentage of killer cells: a smaller inoculum resulted in a higher proportion of killer cells in grape juice fermentations. In all cases, wines obtained with pure-culture fermentations were preferred to mixed-culture fermentations by sensory analysis. The reasons why killer cells do not finish fermentation under competitive conditions with sensitive cells are discussed. PMID:9212430

Direct Visualization of the Hydration Layer on Alumina Nanoparticles with the Fluid Cell STEM in situ

PubMed Central

Firlar, Emre; Çınar, Simge; Kashyap, Sanjay; Akinc, Mufit; Prozorov, Tanya

2015-01-01

Rheological behavior of aqueous suspensions containing nanometer-sized powders is of relevance to many branches of industry. Unusually high viscosities observed for suspensions of nanoparticles compared to those of micron size powders cannot be explained by current viscosity models. Formation of so-called hydration layer on alumina nanoparticles in water was hypothesized, but never observed experimentally. We report here on the direct visualization of aqueous suspensions of alumina with the fluid cell in situ. We observe the hydration layer formed over the particle aggregates and show that such hydrated aggregates constitute new particle assemblies and affect the flow behavior of the suspensions. We discuss how these hydrated nanoclusters alter the effective solid content and the viscosity of nanostructured suspensions. Our findings elucidate the source of high viscosity observed for nanoparticle suspensions and are of direct relevance to many industrial sectors including materials, food, cosmetics, pharmaceutical among others employing colloidal slurries with nanometer-scale particles. PMID:25996055

Cache-enabled small cell networks: modeling and tradeoffs.

PubMed

Baştuǧ, Ejder; Bennis, Mehdi; Kountouris, Marios; Debbah, Mérouane

We consider a network model where small base stations (SBSs) have caching capabilities as a means to alleviate the backhaul load and satisfy users' demand. The SBSs are stochastically distributed over the plane according to a Poisson point process (PPP) and serve their users either (i) by bringing the content from the Internet through a finite rate backhaul or (ii) by serving them from the local caches. We derive closed-form expressions for the outage probability and the average delivery rate as a function of the signal-to-interference-plus-noise ratio (SINR), SBS density, target file bitrate, storage size, file length, and file popularity. We then analyze the impact of key operating parameters on the system performance. It is shown that a certain outage probability can be achieved either by increasing the number of base stations or the total storage size. Our results and analysis provide key insights into the deployment of cache-enabled small cell networks (SCNs), which are seen as a promising solution for future heterogeneous cellular networks.

Direct Visualization of the Hydration Layer on Alumina Nanoparticles with the Fluid Cell STEM in situ.

PubMed

Firlar, Emre; Çınar, Simge; Kashyap, Sanjay; Akinc, Mufit; Prozorov, Tanya

2015-05-21

Rheological behavior of aqueous suspensions containing nanometer-sized powders is of relevance to many branches of industry. Unusually high viscosities observed for suspensions of nanoparticles compared to those of micron size powders cannot be explained by current viscosity models. Formation of so-called hydration layer on alumina nanoparticles in water was hypothesized, but never observed experimentally. We report here on the direct visualization of aqueous suspensions of alumina with the fluid cell in situ. We observe the hydration layer formed over the particle aggregates and show that such hydrated aggregates constitute new particle assemblies and affect the flow behavior of the suspensions. We discuss how these hydrated nanoclusters alter the effective solid content and the viscosity of nanostructured suspensions. Our findings elucidate the source of high viscosity observed for nanoparticle suspensions and are of direct relevance to many industrial sectors including materials, food, cosmetics, pharmaceutical among others employing colloidal slurries with nanometer-scale particles.

Direct visualization of the hydration layer on alumina nanoparticles with the fluid cell STEM in situ

DOE PAGES

Firlar, Emre; Çınar, Simge; Kashyap, Sanjay; ...

2015-05-21

Rheological behavior of aqueous suspensions containing nanometer-sized powders is of relevance to many branches of industry. Unusually high viscosities observed for suspensions of nanoparticles compared to those of micron size powders cannot be explained by current viscosity models. Formation of so-called hydration layer on alumina nanoparticles in water was hypothesized, but never observed experimentally. We report here on the direct visualization of aqueous suspensions of alumina with the fluid cell in situ. We observe the hydration layer formed over the particle aggregates and show that such hydrated aggregates constitute new particle assemblies and affect the flow behavior of the suspensions.more » We discuss how these hydrated nanoclusters alter the effective solid content and the viscosity of nanostructured suspensions. As a result, our findings elucidate the source of high viscosity observed for nanoparticle suspensions and are of direct relevance to many industrial sectors including materials, food, cosmetics, pharmaceutical among others employing colloidal slurries with nanometer-scale particles.« less

Sputter-Grown Sb-DOPED Silicon Nanocrystals Embedded in Silicon-Rich Carbide for si Heterojunction Solar Cells

NASA Astrophysics Data System (ADS)

Chen, Xiaobo; Tang, Yu; Hao, Jiabo

Sb-doped silicon nanocrystals (Si-NCs) films were fabricated by magnetron co-sputtering combined with rapid-thermal annealing. The effects of Sb content on the structural and electrical properties of the films were studied. The dot size increased with the increasing Sb content, and could be correlated to the effect of Sb-induced crystallization. The variation in the concentration of Sb shows a significant impact on the film properties, where as doped with 0.8at.% of Sb exhibited major property improvements when compared with other films. By employing Sb-doped Si-NCs films as emitter layers, Si-NCs/monocrystalline silicon heterojunction solar cells were fabricated and the effect of the Sb doping concentration on the photovoltaic properties was studied. It is found that the doping level in the Si-NCs layer is a key factor in determining the short-circuit current density and power conversion efficiency (PCE). With an optimized doping concentration of 0.8at.% of Sb, a maximal PCE of 7.10% was obtained. This study indicates that the Sb-doped Si-NCs can be good candidates for all-silicon tandem solar cells.

Particle size effects on viscosity of silver pastes: A manufacturer's view

NASA Technical Reports Server (NTRS)

Provance, J.; Allison, K.

1983-01-01

Particles from a variety of silver powders were investigated by scanning electron microscopy and particle size analyses. Particle size distribution curves and volume population graphs were prepared for these silver powders and for glass powders with optimum, extra fine and coarse particle sizes. The viscosity at a given shear rate and slope of viscosity over a range of shear rates were determined for thick film pastes made with these powders. Because of particle anomalies and variations, the need for flexibility to achieve the best printing qualities for silver pastes was evident. It was established that print quality, dried and fired film density and optimum contact of silver particles with silicon, important for cell electrical output, could be achieved by adjusting the slope of viscosity that fell outside of the range, -0.550 to -0.650. This was accomplished through organic vehicle technology that permitted a change in the slope of viscosity, up or down, while maintaining a constant silver and total solids content.

Signalling and the control of skeletal muscle size

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

Otto, Anthony; Patel, Ketan, E-mail: ketan.patel@reading.ac.uk

2010-11-01

Skeletal muscle is highly adaptive to environmental stimuli and can alter its mass accordingly. This tissue is almost unique in that it can increase its size through two distinct mechanisms. It can grow through a cellular process mediated by cell fusion, or it can increase its size simply by increasing its protein content. Understanding how these processes are regulated is crucial for the development of potential therapies against debilitating skeletal muscle wasting diseases. Two key signalling molecules, Insulin like Growth Factor (IGF) and GDF-8/myostatin, have emerged in recent years to be potent regulators of skeletal muscle size. In this reviewmore » we bring together recent data highlighting the important and novel aspects of both molecules and their signalling pathways, culminating in a discussion of the cellular and tissue phenotypic outcomes of their stimulation or antagonism. We emphasise the complex regulatory mechanisms and discuss the temporal and spatial differences that control their action, understanding of which is crucial to further their use as potential therapeutic targets.« less

Fibroblasts Cultured on Nanowires Exhibit Low Motility, Impaired Cell Division, and DNA Damage

PubMed Central

Persson, Henrik; Købler, Carsten; Mølhave, Kristian; Samuelson, Lars; Tegenfeldt, Jonas O; Oredsson, Stina; Prinz, Christelle N

2013-01-01

Nanowires are commonly used as tools for interfacing living cells, acting as biomolecule-delivery vectors or electrodes. It is generally assumed that the small size of the nanowires ensures a minimal cellular perturbation, yet the effects of nanowires on cell migration and proliferation remain largely unknown. Fibroblast behaviour on vertical nanowire arrays is investigated, and it is shown that cell motility and proliferation rate are reduced on nanowires. Fibroblasts cultured on long nanowires exhibit failed cell division, DNA damage, increased ROS content and respiration. Using focused ion beam milling and scanning electron microscopy, highly curved but intact nuclear membranes are observed, showing no direct contact between the nanowires and the DNA. The nanowires possibly induce cellular stress and high respiration rates, which trigger the formation of ROS, which in turn results in DNA damage. These results are important guidelines to the design and interpretation of experiments involving nanowire-based transfection and electrical characterization of living cells. PMID:23813871

Development of lightweight aluminum hollowcore solar cell array technology

NASA Technical Reports Server (NTRS)

Carlson, J. A.

1971-01-01

A baseline configuration for a three section folding array, with retraction capability, was developed which would utilize electroformed aluminum hollowcore substrates and beryllium frames. The three section array was not fabricated because of difficulties with impurities in the aluminum electroforming bath. A procedure was developed for etching the copper mandrel from virtually any size of aluminum hollowcore panel in approximately one hour. Procedures were developed for analyzing the content of peroxide, water, total aluminum, and lithium-aluminum-hydride in an aluminum electroforming solution.

Role of particle size and composition in metal adsorption by solids deposited on urban road surfaces.

PubMed

Gunawardana, Chandima; Egodawatta, Prasanna; Goonetilleke, Ashantha

2014-01-01

Despite common knowledge that the metal content adsorbed by fine particles is relatively higher compared to coarser particles, the reasons for this phenomenon have gained little research attention. The research study discussed in the paper investigated the variations in metal content for different particle sizes of solids associated with pollutant build-up on urban road surfaces. Data analysis confirmed that parameters favourable for metal adsorption to solids such as specific surface area, organic carbon content, effective cation exchange capacity and clay forming minerals content decrease with the increase in particle size. Furthermore, the mineralogical composition of solids was found to be the governing factor influencing the specific surface area and effective cation exchange capacity. There is high quartz content in particles >150 μm compared to particles <150 μm. As particle size reduces below 150 μm, the clay forming minerals content increases, providing favourable physical and chemical properties that influence adsorption. Copyright © 2013 Elsevier Ltd. All rights reserved.

Stress Wave E-Rating of Structural Timber—Size and Moisture Content Effects

Treesearch

Xiping Wang

2013-01-01

The objectives of this study were to investigate the influence of cross sectional size and moisture content on stress wave properties of structural timber in various sizes and evaluate the feasibility of using stress wave method to E-rate timber in green conditions. Four different sizes of Douglas-fir (Pseudotsuga menziesii) square timbers were...

Preparation of brookite TiO2 nanoparticles with small sizes and the improved photovoltaic performance of brookite-based dye-sensitized solar cells.

PubMed

Xu, Jinlei; Wu, Shufang; Jin, Jingpeng; Peng, Tianyou

2016-11-10

Brookite TiO 2 nanoparticles with small sizes (hereafter denoted as BTP particles) were synthesized through the hydrothermal treatment of TiCl 4 solution with Pb(NO 3 ) 2 as an additive. The obtained BTP particles have a large specific surface area (∼122.2 m 2 g -1 ) and relatively uniform particle sizes (∼10 nm) with the coexistence of a small quantity of nanorods with a length of ∼100 nm. When used as a photoanode material for dye-sensitized solar cells (DSSCs), the BTP particles show a much higher dye-loading content than the brookite TiO 2 quasi nanocubes (denoted as BTN particles) with a mean size of ∼50 nm and a specific surface area of ∼34.2 m 2 g -1 that were prepared through a similar hydrothermal process but without the addition of Pb(NO 3 ) 2 . The fabricated BTP film-based solar cell with an optimized film thickness gives a conversion efficiency up to 6.36% with a 74% improvement when compared to the BTN film-based one (3.65%) under AM 1.5G one sun irradiation, while the corresponding bilayer brookite-based solar cell by using brookite TiO 2 submicrometer particles as an overlayer of the BTP film displays a significantly enhanced efficiency of 7.64%. Both of them exceed the current record (5.97%) for the conversion efficiency of pure brookite-based DSSCs reported in the literature. The present results not only demonstrate a really simple synthesis of brookite TiO 2 nanoparticles with both high phase purity and a large surface area, but also offer an efficient approach to improve the photovoltaic performance of brookite-based solar cells by offsetting brookite's inherent shortages such as lower dye-loading and poor conductivity as compared to anatase.

Electrostatic bio-manipulation for the modification of cellular functions

NASA Astrophysics Data System (ADS)

Washizu, Masao

2013-03-01

The use of electrostatic field effects, including field-induced reversible-breakdown of the membrane and dielectrophoresis (DEP), in microfabricated structures are investigated. With the use of field constriction created by a micro-orifice whose diameter is smaller than the cells, controlled magnitude of pulsed voltage can be applied across the cell membrane regardless of the cell size, shape or orientation. As a result, the breakdown occurs reproducibly and with minimal invasiveness. The breakdown is used for two purposes, electroporation by which foreign substances can be fed into cells, and electrofusion which creates genetic and/or cytoplasmic mixture among two cells. When GFP plasmid is fed into MSC cell, the gene expression started within 2 hours, and finally observed in more than 50% of cells. For cell fusion, several ten percent fusion yield is achieved for most cell types, with the colony formation in several percents. Timing-controlled feeding foreign substances or mixing cellular contents, with high-yield and low-invasiveness, is expected to bring about a new technology for both genetic and epigenetic modifications of cellular functions, in such field as regenerative medicine.

Scalable topographies to support proliferation and Oct4 expression by human induced pluripotent stem cells

PubMed Central

Reimer, Andreas; Vasilevich, Aliaksei; Hulshof, Frits; Viswanathan, Priyalakshmi; van Blitterswijk, Clemens A.; de Boer, Jan; Watt, Fiona M.

2016-01-01

It is well established that topographical features modulate cell behaviour, including cell morphology, proliferation and differentiation. To define the effects of topography on human induced pluripotent stem cells (iPSC), we plated cells on a topographical library containing over 1000 different features in medium lacking animal products (xeno-free). Using high content imaging, we determined the effect of each topography on cell proliferation and expression of the pluripotency marker Oct4 24 h after seeding. Features that maintained Oct4 expression also supported proliferation and cell-cell adhesion at 24 h, and by 4 days colonies of Oct4-positive, Sox2-positive cells had formed. Computational analysis revealed that small feature size was the most important determinant of pluripotency, followed by high wave number and high feature density. Using this information we correctly predicted whether any given topography within our library would support the pluripotent state at 24 h. This approach not only facilitates the design of substrates for optimal human iPSC expansion, but also, potentially, identification of topographies with other desirable characteristics, such as promoting differentiation. PMID:26757610

Scalable topographies to support proliferation and Oct4 expression by human induced pluripotent stem cells.

PubMed

Reimer, Andreas; Vasilevich, Aliaksei; Hulshof, Frits; Viswanathan, Priyalakshmi; van Blitterswijk, Clemens A; de Boer, Jan; Watt, Fiona M

2016-01-13

It is well established that topographical features modulate cell behaviour, including cell morphology, proliferation and differentiation. To define the effects of topography on human induced pluripotent stem cells (iPSC), we plated cells on a topographical library containing over 1000 different features in medium lacking animal products (xeno-free). Using high content imaging, we determined the effect of each topography on cell proliferation and expression of the pluripotency marker Oct4 24 h after seeding. Features that maintained Oct4 expression also supported proliferation and cell-cell adhesion at 24 h, and by 4 days colonies of Oct4-positive, Sox2-positive cells had formed. Computational analysis revealed that small feature size was the most important determinant of pluripotency, followed by high wave number and high feature density. Using this information we correctly predicted whether any given topography within our library would support the pluripotent state at 24 h. This approach not only facilitates the design of substrates for optimal human iPSC expansion, but also, potentially, identification of topographies with other desirable characteristics, such as promoting differentiation.

The disposition of DNA in Prochloron (Prochlorophyta)

NASA Technical Reports Server (NTRS)

Coleman, A. W.; Lewin, R. A.

1983-01-01

The discovery of both chlorophyll a and b in the prokaryote Prochloron Lewin, a trait otherwise unique to eukaryotic photosynthetic organisms, has stimulated speculation on the possible endosymbiont origins of the plastids of eukaryotic cells. The arrangement of DNA in Prochloron was therefore dyed in situ with the fluorochrome dye DAPI and compared with the plastid DNA of various eukaryote cells. The DNA of Prochloron is found to be clearly different in arrangement and locale from that of blue-green algae. In the great size of its nucleoids and their apparently high DNA content, Prochloron also differs from the plastids of any eukaryotes, with the possible exception of dinoflagellates. Prochloron remains an evolutionary puzzle.

A microchip electrophoresis-mass spectrometric platform with double cell lysis nano-electrodes for automated single cell analysis.

PubMed

Li, Xiangtang; Zhao, Shulin; Hu, Hankun; Liu, Yi-Ming

2016-06-17

Capillary electrophoresis-based single cell analysis has become an essential approach in researches at the cellular level. However, automation of single cell analysis has been a challenge due to the difficulty to control the number of cells injected and the irreproducibility associated with cell aggregation. Herein we report the development of a new microfluidic platform deploying the double nano-electrode cell lysis technique for automated analysis of single cells with mass spectrometric detection. The proposed microfluidic chip features integration of a cell-sized high voltage zone for quick single cell lysis, a microfluidic channel for electrophoretic separation, and a nanoelectrospray emitter for ionization in MS detection. Built upon this platform, a microchip electrophoresis-mass spectrometric method (MCE-MS) has been developed for automated single cell analysis. In the method, cell introduction, cell lysis, and MCE-MS separation are computer controlled and integrated as a cycle into consecutive assays. Analysis of large numbers of individual PC-12 neuronal cells (both intact and exposed to 25mM KCl) was carried out to determine intracellular levels of dopamine (DA) and glutamic acid (Glu). It was found that DA content in PC-12 cells was higher than Glu content, and both varied from cell to cell. The ratio of intracellular DA to Glu was 4.20±0.8 (n=150). Interestingly, the ratio drastically decreased to 0.38±0.20 (n=150) after the cells are exposed to 25mM KCl for 8min, suggesting the cells released DA promptly and heavily while they released Glu at a much slower pace in response to KCl-induced depolarization. These results indicate that the proposed MCE-MS analytical platform may have a great potential in researches at the cellular level. Copyright © 2016 Elsevier B.V. All rights reserved.

Early Changes in the Ultrastructure of Streptococcus faecalis After Amino Acid Starvation

PubMed Central

Higgins, M. L.; Shockman, G. D.

1970-01-01

Thin sections of Streptococcus faecalis (ATCC 9790) starved of one essential amino acid (threonine or valine) initially show rapid increases in (i) cell wall thickness, (ii) the apparent size of the central nucleoid region, and (iii) mesosomal membranes. The most rapid increases in all three variables occurred during the first 1 to 2 hr of starvation. After this initial period, the rates progressively decreased over the 20-hr observation period. During threonine starvation, the mesosomal membrane that accumulated in the first hour was subsequently degraded and reached a level similar to that found in exponential-phase cells after 20 hr. With valine starvation, mesosomal membrane continued to slowly accumulate over the entire 20-hr observation period. The mesosomes of the starved cells retained the same “stalked-bag” morphology of those in exponential-phase cells. These cytological observations agree with previously published biochemical data on membrane lipid and wall content after starvation. Images PMID:4987306

Electrochemical characterization of nano-sized Pd-based catalysts as cathode materials in direct methanol fuel cells.

PubMed

Choi, M; Han, C; Kim, I T; An, J C; Lee, J J; Lee, H K; Shim, J

2011-01-01

To improve the catalytic activity of palladium (Pd) as a cathode catalyst in direct methanol fuel cells (DMFCs), we prepared palladium-titanium oxide (Pd-TiO2) catalysts which the Pd and TiO2 nanoparticles were simultaneously impregnated on carbon. We selected Pd and TiO2 as catalytic materials because of their electrochemical stability in acid solution. The crystal structure and the loading amount of Pd and TiO2 on carbon were characterized by X-ray diffraction (XRD) and energy dispersive X-ray microanalysis (EDX). The electrochemical characterization of Pd-TiO2/C catalysts for the oxygen reduction reaction was carried out in half and single cell systems. The catalytic activities of the Pd-TiO2 catalysts were strongly influenced by the TiO2 content. In the single cell test, the Pd-TiO2 catalysts showed very comparable performance to the Pt catalyst.

Biotechnology

NASA Image and Video Library

2003-05-07

Aboard the International Space Station (ISS), the Tissue Culture Module (TCM) is the stationary bioreactor vessel in which cell cultures grow. However, for the Cellular Biotechnology Operations Support Systems-Fluid Dynamics Investigation (CBOSS-FDI), color polystyrene beads are used to measure the effectiveness of various mixing procedures. Uniform mixing is a crucial component of CBOSS experiments involving the immune response of human lymphoid cell suspensions. In this picture, the beads are trapped in the injection port shortly after injection. Swirls of beads indicate, event to the naked eye, the contents of the TCM are not fully mixed. The beads are similar in size and density to human lymphoid cells. The goal is to develop procedures that are both convenient for the flight crew and are optimal in providing uniform and reproducible mixing of all components, including cells. The average bead density in a well mixed TCM will be uniform, with no bubbles, and it will be measured using the absorption of light

Toxicity of tungsten carbide and cobalt-doped tungsten carbide nanoparticles in mammalian cells in vitro.

PubMed

Bastian, Susanne; Busch, Wibke; Kühnel, Dana; Springer, Armin; Meissner, Tobias; Holke, Roland; Scholz, Stefan; Iwe, Maria; Pompe, Wolfgang; Gelinsky, Michael; Potthoff, Annegret; Richter, Volkmar; Ikonomidou, Chrysanthy; Schirmer, Kristin

2009-04-01

Tungsten carbide nanoparticles are being explored for their use in the manufacture of hard metals. To develop nanoparticles for broad applications, potential risks to human health and the environment should be evaluated and taken into consideration. We aimed to assess the toxicity of well-characterized tungsten carbide (WC) and cobalt-doped tungsten carbide (WC-Co) nanoparticle suspensions in an array of mammalian cells. We examined acute toxicity of WC and of WC-Co (10% weight content Co) nanoparticles in different human cell lines (lung, skin, and colon) as well as in rat neuronal and glial cells (i.e., primary neuronal and astroglial cultures and the oligodendrocyte precursor cell line OLN-93). Furthermore, using electron microscopy, we assessed whether nanoparticles can be taken up by living cells. We chose these in vitro systems in order to evaluate for potential toxicity of the nanoparticles in different mammalian organs (i.e., lung, skin, intestine, and brain). Chemical-physical characterization confirmed that WC as well as WC-Co nanoparticles with a mean particle size of 145 nm form stable suspensions in serum-containing cell culture media. WC nanoparticles were not acutely toxic to the studied cell lines. However, cytotoxicity became apparent when particles were doped with Co. The most sensitive were astrocytes and colon epithelial cells. Cytotoxicity of WC-Co nanoparticles was higher than expected based on the ionic Co content of the particles. Analysis by electron microscopy demonstrated presence of WC nanoparticles within mammalian cells. Our findings demonstrate that doping of WC nanoparticles with Co markedly increases their cytotoxic effect and that the presence of WC-Co in particulate form is essential to elicit this combinatorial effect.

Toxicity of Tungsten Carbide and Cobalt-Doped Tungsten Carbide Nanoparticles in Mammalian Cells in Vitro

PubMed Central

Bastian, Susanne; Busch, Wibke; Kühnel, Dana; Springer, Armin; Meißner, Tobias; Holke, Roland; Scholz, Stefan; Iwe, Maria; Pompe, Wolfgang; Gelinsky, Michael; Potthoff, Annegret; Richter, Volkmar; Ikonomidou, Chrysanthy; Schirmer, Kristin

2009-01-01

Background Tungsten carbide nanoparticles are being explored for their use in the manufacture of hard metals. To develop nanoparticles for broad applications, potential risks to human health and the environment should be evaluated and taken into consideration. Objective We aimed to assess the toxicity of well-characterized tungsten carbide (WC) and cobaltdoped tungsten carbide (WC-Co) nanoparticle suspensions in an array of mammalian cells. Methods We examined acute toxicity of WC and of WC-Co (10% weight content Co) nanoparticles in different human cell lines (lung, skin, and colon) as well as in rat neuronal and glial cells (i.e., primary neuronal and astroglial cultures and the oligodendro cyte precursor cell line OLN-93). Furthermore, using electron microscopy, we assessed whether nanoparticles can be taken up by living cells. We chose these in vitro systems in order to evaluate for potential toxicity of the nanoparticles in different mammalian organs (i.e., lung, skin, intestine, and brain). Results Chemical–physical characterization confirmed that WC as well as WC-Co nanoparticles with a mean particle size of 145 nm form stable suspensions in serum-containing cell culture media. WC nanoparticles were not acutely toxic to the studied cell lines. However, cytotoxicity became apparent when particles were doped with Co. The most sensitive were astrocytes and colon epithelial cells. Cytotoxicity of WC-Co nanoparticles was higher than expected based on the ionic Co content of the particles. Analysis by electron microscopy demonstrated presence of WC nanoparticles within mammalian cells. Conclusions Our findings demonstrate that doping of WC nanoparticles with Co markedly increases their cytotoxic effect and that the presence of WC-Co in particulate form is essential to elicit this combinatorial effect. PMID:19440490

Selective antibacterial effects of mixed ZnMgO nanoparticles

NASA Astrophysics Data System (ADS)

Vidic, Jasmina; Stankic, Slavica; Haque, Francia; Ciric, Danica; Le Goffic, Ronan; Vidy, Aurore; Jupille, Jacques; Delmas, Bernard

2013-05-01

Antibiotic resistance has impelled the research for new agents that can inhibit bacterial growth without showing cytotoxic effects on humans and other species. We describe the synthesis and physicochemical characterization of nanostructured ZnMgO whose antibacterial activity was compared to its pure nano-ZnO and nano-MgO counterparts. Among the three oxides, ZnO nanocrystals—with the length of tetrapod legs about 100 nm and the diameter about 10 nm—were found to be the most effective antibacterial agents since both Gram-positive ( B. subtilis) and Gram-negative ( E. coli) bacteria were completely eradicated at concentration of 1 mg/mL. MgO nanocubes (the mean cube size 50 nm) only partially inhibited bacterial growth, whereas ZnMgO nanoparticles (sizes corresponding to pure particles) revealed high specific antibacterial activity to Gram-positive bacteria at this concentration. Transmission electron microscopy analysis showed that B. subtilis cells were damaged after contact with nano-ZnMgO, causing cell contents to leak out. Our preliminary toxicological study pointed out that nano-ZnO is toxic when applied to human HeLa cells, while nano-MgO and the mixed oxide did not induce any cell damage. Overall, our results suggested that nanostructured ZnMgO, may reconcile efficient antibacterial efficiency while being a safe new therapeutic for bacterial infections.

Near Infrared Spectroscopy for On-line Monitoring of Alkali- Free Cloth/Phenolic Resin Prepreg During Manufacture

PubMed Central

Jiang, Bo; Huang, Yu Dong

2007-01-01

A NIR method was developed for the on-line monitoring of alkali-free cloth/phenolic resin prepreg during its manufacturing process. First, the sizing content of the alkali-free cloth was analyzed, and then the resin, soluble resin and volatiles content of the prepreg was analyzed simultaneously using the FT-NIR spectrometer. Partial least square (PLS) regression was used to develop the calibration models, which for the sizing content was preprocessed by 1stDER +MSC, for the volatile content by 1stDER +VN, for the soluble resin content by 1stDER +MSC and for the resin content by the VN spectral data preprocessing method. RMSEP of the prediction model for the sizing content was 0.732 %, for the resin content it was 0.605, for the soluble resin content it was 0.101 and for volatiles content it was 0.127. The results of the paired t-test revealed that there was no significant difference between the NIR method and the standard method. The NIR spectroscopy method could be used to predict the resin, soluble resin and the volatiles content of the prepreg simultaneously, as well as sizing content of alkali-free cloth. The processing parameters of the prepreg during manufacture could be adjusted quickly with the help of the NIR analysis results. The results indicated that the NIR spectroscopy method was sufficiently accurate and effective for the on-line monitoring of alkali-free cloth/phenolic resin prepreg.

Assessment of Cultivation Factors that Affect Biomass and Geraniol Production in Transgenic Tobacco Cell Suspension Cultures

PubMed Central

Vasilev, Nikolay; Schmitz, Christian; Grömping, Ulrike; Fischer, Rainer; Schillberg, Stefan

2014-01-01

A large-scale statistical experimental design was used to determine essential cultivation parameters that affect biomass accumulation and geraniol production in transgenic tobacco (Nicotiana tabacum cv. Samsun NN) cell suspension cultures. The carbohydrate source played a major role in determining the geraniol yield and factors such as filling volume, inoculum size and light were less important. Sucrose, filling volume and inoculum size had a positive effect on geraniol yield by boosting growth of plant cell cultures whereas illumination of the cultures stimulated the geraniol biosynthesis. We also found that the carbohydrates sucrose and mannitol showed polarizing effects on biomass and geraniol accumulation. Factors such as shaking frequency, the presence of conditioned medium and solubilizers had minor influence on both plant cell growth and geraniol content. When cells were cultivated under the screened conditions for all the investigated factors, the cultures produced ∼5.2 mg/l geraniol after 12 days of cultivation in shaking flasks which is comparable to the yield obtained in microbial expression systems. Our data suggest that industrial experimental designs based on orthogonal arrays are suitable for the selection of initial cultivation parameters prior to the essential medium optimization steps. Such designs are particularly beneficial in the early optimization steps when many factors must be screened, increasing the statistical power of the experiments without increasing the demand on time and resources. PMID:25117009

Assessment of cultivation factors that affect biomass and geraniol production in transgenic tobacco cell suspension cultures.

PubMed

Vasilev, Nikolay; Schmitz, Christian; Grömping, Ulrike; Fischer, Rainer; Schillberg, Stefan

2014-01-01

A large-scale statistical experimental design was used to determine essential cultivation parameters that affect biomass accumulation and geraniol production in transgenic tobacco (Nicotiana tabacum cv. Samsun NN) cell suspension cultures. The carbohydrate source played a major role in determining the geraniol yield and factors such as filling volume, inoculum size and light were less important. Sucrose, filling volume and inoculum size had a positive effect on geraniol yield by boosting growth of plant cell cultures whereas illumination of the cultures stimulated the geraniol biosynthesis. We also found that the carbohydrates sucrose and mannitol showed polarizing effects on biomass and geraniol accumulation. Factors such as shaking frequency, the presence of conditioned medium and solubilizers had minor influence on both plant cell growth and geraniol content. When cells were cultivated under the screened conditions for all the investigated factors, the cultures produced ∼ 5.2 mg/l geraniol after 12 days of cultivation in shaking flasks which is comparable to the yield obtained in microbial expression systems. Our data suggest that industrial experimental designs based on orthogonal arrays are suitable for the selection of initial cultivation parameters prior to the essential medium optimization steps. Such designs are particularly beneficial in the early optimization steps when many factors must be screened, increasing the statistical power of the experiments without increasing the demand on time and resources.

Effect of crystals and fibrous network polymer additives on cellular morphology of microcellular foams

NASA Astrophysics Data System (ADS)

Miyamoto, Ryoma; Utano, Tatsumi; Yasuhara, Shunya; Ishihara, Shota; Ohshima, Masahiro

2015-05-01

In this study, the core-back foam injection molding was used for preparing microcelluar polypropylene (PP) foam with either a 1,3:2,4 bis-O-(4-methylbenzylidene)-D-sorbitol gelling agent (Gel-all MD) or a fibros network polymer additive (Metablen 3000). Both agent and addiive could effectively control the celluar morphology in foams but somehow different ways. In course of cooling the polymer with Gel-all MD in the mold caity, the agent enhanced the crystal nucleation and resulted in the large number of small crystals. The crystals acted as effective bubble nucleation agent in foaming process. Thus, the agent reduced the cell size and increased the cell density, drastically. Furthermore, the small crystals provided an inhomogenuity to the expanding cell wall and produced the high open cell content with nano-scale fibril structure. Gell-all as well as Metablene 3000 formed a gel-like fibrous network in melt. The network increased the elongational viscosity and tended to prevent the cell wall from breaking up. The foaming temperature window was widened by the presence of the network. Especially, the temperature window where the macro-fibrous structure was formed was expanded to the higher temperature. The effects of crystal nucleating agent and PTFE on crystals' size and number, viscoelsticity, rheological propreties of PP and cellular morphology were compared and thorougly investigated.

The Effects of Perfluorinated Chemicals on Adipoctye ...

EPA Pesticide Factsheets

The 3T3-L1 preadipocyte culture system has been used to examine numerous compounds that influence adipocyte differentiation or function. The perfluoroalkyl acids (PFAAs), used as surfactants in a variety of industrial applications, are of concern as environmental contaminants that are detected worldwide in human serum and animal tissues. This study was designed to evaluate the potential for PFAAs to affect adipocyte differentiation and lipid accumulation using mouse 3T3-L1 cells. Cells were treated with perfluorooctanoic acid (PFOA) (5-100 IJM), perfluorononanoic acid (PFNA) (5-100 1JM), perfluorooctane sulfonate (PFOS) (50-300 IJM}, perfluorohexane sulfonate (PFHxS) (40-250 IJM), the peroxisome proliferator activated receptor (PPAR) PPARa agonist Wyeth-14,643 (WY-14,643), and the PPARy agonist rosiglitazone. The PPARy agonist was included as a positive control as this pathway is critical to adipocyte differentiation. The PPARa agonist was included as the PFAA compounds are known activators of this pathway. Cells were assessed morphometrically and biochemically for number, size, and lipid content. RNA was extracted for qPCR analysis of 13 genes selected for their importance in adipocyte differentiation and lipid metabolism. There was a significant concentration-related increase in cell number and decreased cell size after exposure to PFOA, PFHxS, PFOS, and PFNA. All four PFAA treatments produced a concentration-related decrease in the calculated average area oc

Degradation Mechanisms in Solid-Oxide Fuel and Electrolyzer Cells: Analytical Description of Nickel Agglomeration in a Ni /Y S Z Electrode

NASA Astrophysics Data System (ADS)

Kröll, L.; de Haart, L. G. J.; Vinke, I.; Eichel, R.-A.

2017-04-01

The microstructural evolution of a porous electrode consisting of a metal-ceramic matrix, consisting of nickel and yttria-stabilized zirconia (Y S Z ), is one of the main degradation mechanisms in a solid-oxide cell (SOC), in either fuel cell or electrolyzer mode. In that respect, the agglomeration of nickel particles in a SOC electrode leads to a decrease in the electronic conductivity as well as in the active catalytic area for the oxidation-reduction reaction of the fuel-water steam. An analytical model of the agglomeration behavior of a Ni /Y S Z electrode is proposed that allows for a quantitative description of the nickel agglomeration. The accuracy of the model is validated in terms of a comparison with experimental degradation measurements. The model is based on contact probabilities of nickel clusters in a porous network of nickel and Y S Z , derived from an algorithm of the agglomeration process. The iterative algorithm is converted into an analytical function, which involves structural parameters of the electrode, such as the porosity and the nickel content. Furthermore, to describe the agglomeration mechanism, the influence of the steam content and the flux rate are taken into account via reactions on the nickel surface. In the next step, the developed agglomeration model is combined with the mechanism of the Ostwald ripening. The calculated grain-size growth is compared to measurements at different temperatures and under low flux rates and low steam content, as well as under high flux rates and high steam content. The results confirm the necessity of connecting the two mechanisms and clarify the circumstances in which the single processes occur and how they contribute to the total agglomeration of the particles in the electrode.

Proinsulin atypical maturation and disposal induces extensive defects in mouse Ins2+/Akita β-cells.

PubMed

Yuan, Qingxin; Tang, Wei; Zhang, Xiaoping; Hinson, Jack A; Liu, Chao; Osei, Kwame; Wang, Jie

2012-01-01

Because of its low relative folding rate and plentiful manufacture in β-cells, proinsulin maintains a homeostatic balance of natively and plentiful non-natively folded states (i.e., proinsulin homeostasis, PIHO) through the integration of maturation and disposal processes. PIHO is susceptible to genetic and environmental influences, and its disorder has been critically linked to defects in β-cells in diabetes. To explore this hypothesis, we performed polymerase chain reaction (PCR), metabolic-labeling, immunoblotting, and histological studies to clarify what defects result from primary disorder of PIHO in model Ins2(+/Akita) β-cells. We used T antigen-transformed Ins2(+/Akita) and control Ins2(+/+) β-cells established from Akita and wild-type littermate mice. In Ins2(+/Akita) β-cells, we found no apparent defect at the transcriptional and translational levels to contribute to reduced cellular content of insulin and its precursor and secreted insulin. Glucose response remained normal in proinsulin biosynthesis but was impaired for insulin secretion. The size and number of mature insulin granules were reduced, but the size/number of endoplasmic reticulum, Golgi, mitochondrion, and lysosome organelles and vacuoles were expanded/increased. Moreover, cell death increased, and severe oxidative stress, which manifested as increased reactive oxygen species, thioredoxin-interacting protein, and protein tyrosine nitration, occurred in Ins2(+/Akita) β-cells and/or islets. These data show the first clear evidence that primary PIHO imbalance induces severe oxidative stress and impairs glucose-stimulated insulin release and β-cell survival as well as producing other toxic consequences. The defects disclosed/clarified in model Ins2(+/Akita) β-cells further support a role of the genetic and stress-susceptible PIHO disorder in β-cell failure and diabetes.

Proinsulin Atypical Maturation and Disposal Induces Extensive Defects in Mouse Ins2+/Akita β-Cells

PubMed Central

Zhang, Xiaoping; Hinson, Jack A.; Liu, Chao; Osei, Kwame; Wang, Jie

2012-01-01

Because of its low relative folding rate and plentiful manufacture in β-cells, proinsulin maintains a homeostatic balance of natively and plentiful non-natively folded states (i.e., proinsulin homeostasis, PIHO) through the integration of maturation and disposal processes. PIHO is susceptible to genetic and environmental influences, and its disorder has been critically linked to defects in β-cells in diabetes. To explore this hypothesis, we performed polymerase chain reaction (PCR), metabolic-labeling, immunoblotting, and histological studies to clarify what defects result from primary disorder of PIHO in model Ins2+/Akita β-cells. We used T antigen-transformed Ins2+/Akita and control Ins2+/+ β-cells established from Akita and wild-type littermate mice. In Ins2+/Akita β-cells, we found no apparent defect at the transcriptional and translational levels to contribute to reduced cellular content of insulin and its precursor and secreted insulin. Glucose response remained normal in proinsulin biosynthesis but was impaired for insulin secretion. The size and number of mature insulin granules were reduced, but the size/number of endoplasmic reticulum, Golgi, mitochondrion, and lysosome organelles and vacuoles were expanded/increased. Moreover, cell death increased, and severe oxidative stress, which manifested as increased reactive oxygen species, thioredoxin-interacting protein, and protein tyrosine nitration, occurred in Ins2+/Akita β-cells and/or islets. These data show the first clear evidence that primary PIHO imbalance induces severe oxidative stress and impairs glucose-stimulated insulin release and β-cell survival as well as producing other toxic consequences. The defects disclosed/clarified in model Ins2+/Akita β-cells further support a role of the genetic and stress-susceptible PIHO disorder in β-cell failure and diabetes. PMID:22509386

Development of a novel folate-modified nanobubbles with improved targeting ability to tumor cells.

PubMed

Duan, Sujuan; Guo, Lu; Shi, Dandan; Shang, Mengmeng; Meng, Dong; Li, Jie

2017-07-01

Conjugation of folate (FOL) to nanobubbles could enhance the selective targeting to tumors expressing high levels of folate receptor (FR). To further improve the selective targeting ability of FOL-modified nanobubbles, a novel FOL-targeted nanobubble ((FOL) 2 -NB) with increasing FOL content (accomplished by linking two FOL molecules per DSPE-PEG2000 chain) was synthesized, through the methods of mechanical shaking and low-speed centrifugation based on lipid-stabilized perfluoropropane. The bubble size and distribution range were measured by dynamic light scattering (DLS). Enhanced imaging ability was evaluated using a custom-made agarose mold with a clinical US imaging system at mechanical indices of up to 0.12 at a center frequency of 9.0MHz. Targeted ability was also carried out in human breast cancer MCF-7 cells, which over-express the FR, by fluorescence activated cell sorting (FACS) and fluorescence microscopy, respectively. (FOL) 2 -NB with a particle size of 286.87±22.96nm were successfully prepared, and they exhibited superior contrast imaging effect. FACS and fluorescence microscopy studies showed greater cellular targeting ability in the group of (FOL) 2 -NB than in their control group of Non-targeted-NB (no FOL targeted nanobubbles) and FOL-NB (one FOL molecule per DSPE-PEG2000 chain). These results suggest that a new type of stronger targeted nanobubble was successfully prepared by increasing the FOL content per DSPE-PEG2000 chain. This novel (FOL) 2 -NBs are potentially useful for ultrasound molecular imaging and treatment of FR-positive tumors and are worthy for further investigation. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation and Evaluations of Mangiferin-Loaded PLGA Scaffolds for Alveolar Bone Repair Treatment Under the Diabetic Condition.

PubMed

Li, Hao; Liao, Hongbing; Bao, Chongyun; Xiao, Yu; Wang, Qi

2017-02-01

The aim of the present study was to prepare and evaluate a sustained-release mangiferin scaffold for improving alveolar bone defect repair in diabetes. Mangiferin-loaded poly(D,L-lactide-co-glycolide) (PLGA) scaffolds were prepared using a freeze-drying technique with ice particles as the porogen material. The produced scaffolds were examined using a scanning electron microscope (SEM). Drug content and drug release were detected using a spectrophotometer. Degradation behaviors were monitored as a measure of weight loss and examined using SEM. Then, the scaffolds were incubated with rat bone marrow stromal cells under the diabetic condition in vitro, and cell viability was assessed using an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Afterward, the scaffolds were implanted into alveolar bone defects of diabetic rats, and bone repair was examined using hematoxylin and eosin staining. The fabricated scaffolds showed porous structures, with average pore size range from 111.35 to 169.45 μm. A higher PLGA concentration led to decreased average pore size. A lower PLGA concentration or a higher mangiferin concentration resulted in increased drug content. The prepared scaffolds released mangiferin in a sustained manner with relatively low initial burst during 10 weeks. Their degradation ratios gradually increased as degradation proceeded. The mangiferin-loaded scaffolds attenuated cell viability decrease under the diabetic condition in vitro. Moreover, they increased histological scorings of bone regeneration and improved delayed alveolar bone defect healing in diabetic rats. These results suggest that the produced mangiferin-loaded scaffolds may provide a potential approach in the treatment of impaired alveolar bone healing in diabetes.

TOC as a regional sediment conditionindicator: Parsing effects of grain size and organic content

EPA Science Inventory

TOC content of sediments is often used as an indicator of benthic condition. Percent TOC is generally positively correlated with sediment percent fines. While sediment grain size may have impacts on benthic organisms independent of organic content, it is often not explicitly co...

TOC as a regional sediment condition indicator: Parsing effects of grain size and organic content

EPA Science Inventory

TOC content of sediments is often used as an indicator of benthic condition. Percent TOC is generally positively correlated with sediment percent fines. While sediment grain size may have impacts on benthic organisms independent of organic content, it is often not explicitly co...

Water as foaming agent for open cell polyurethane structures.

PubMed

Haugen, H; Ried, V; Brunner, M; Will, J; Wintermantel, E

2004-04-01

The problem of moisture in polymer processing is known to any polymer engineer, as air bubbles may be formed. Hence granulates are generally dried prior to manufacturing. This study tried to develop a novel processing methods for scaffolds with controlled moisture content in thermoplastic polyurethane. The common foaming agents for polyurethane are organic solvents, whose residues remaining in the scaffold may be harmful to adherent cells, protein growth factors or nearby tissues. Water was used as a foaming agent and NaCl was used as porogens to achieve an open-cell structure. The polyether-polyurethane samples were processed in a heated press, and achieved a porosity of 64%. The pore size ranged between 50 and 500 microm. Human fibroblasts adhered and proliferate in the scaffold. A non-toxic production process was developed to manufacture a porous structure with a thermoplastic polyether-polyurethane. The process enables a mass-production of samples with adjustable pore size and porosity. In contrast to an existing method (solvent casting), the processing of the samples was not limited by its thickness. The process parameters, which attribute mostly to the pore building, were filling volume, temperature, NaCl-concentration and water-uptake rate.

Gradients in pore size enhance the osteogenic differentiation of human mesenchymal stromal cells in three-dimensional scaffolds

NASA Astrophysics Data System (ADS)

di Luca, Andrea; Ostrowska, Barbara; Lorenzo-Moldero, Ivan; Lepedda, Antonio; Swieszkowski, Wojcech; van Blitterswijk, Clemens; Moroni, Lorenzo

2016-03-01

Small fractures in bone tissue can heal by themselves, but in case of larger defects current therapies are not completely successful due to several drawbacks. A possible strategy relies on the combination of additive manufactured polymeric scaffolds and human mesenchymal stromal cells (hMSCs). The architecture of bone tissue is characterized by a structural gradient. Long bones display a structural gradient in the radial direction, while flat bones in the axial direction. Such gradient presents a variation in bone density from the cancellous bone to the cortical bone. Therefore, scaffolds presenting a gradient in porosity could be ideal candidates to improve bone tissue regeneration. In this study, we present a construct with a discrete gradient in pore size and characterize its ability to further support the osteogenic differentiation of hMSCs. Furthermore, we studied the behaviour of hMSCs within the different compartments of the gradient scaffolds, showing a correlation between osteogenic differentiation and ECM mineralization, and pore dimensions. Alkaline phosphatase activity and calcium content increased with increasing pore dimensions. Our results indicate that designing structural porosity gradients may be an appealing strategy to support gradual osteogenic differentiation of adult stem cells.

Complexities of bloom dynamics in the toxic dinoflagellate Alexandrium fundyense revealed through DNA measurements by imaging flow cytometry coupled with species-specific rRNA probes

NASA Astrophysics Data System (ADS)

Brosnahan, Michael L.; Farzan, Shahla; Keafer, Bruce A.; Sosik, Heidi M.; Olson, Robert J.; Anderson, Donald M.

2014-05-01

Measurements of the DNA content of different protist populations can shed light on a variety of processes, including cell division, sex, prey ingestion, and parasite invasion. Here, we modified an Imaging FlowCytobot (IFCB), a custom-built flow cytometer that records images of microplankton, to measure the DNA content of large dinoflagellates and other high-DNA content species. The IFCB was also configured to measure fluorescence from Cy3-labeled rRNA probes, aiding the identification of Alexandrium fundyense (syn. A. tamarense Group I), a photosynthetic dinoflagellate that causes paralytic shellfish poisoning (PSP). The modified IFCB was used to analyze samples from the development, peak and termination phases of an inshore A. fundyense bloom (Salt Pond, Eastham, MA, USA), and from a rare A. fundyense ‘red tide’ that occurred in the western Gulf of Maine, offshore of Portsmouth, NH (USA). Diploid or G2 phase (‘2C’) A. fundyense cells were frequently enriched at the near-surface, suggesting an important role for aggregation at the air-sea interface during sexual events. Also, our analysis showed that large proportions of A. fundyense cells in both the Salt Pond and red tide blooms were planozygotes during bloom decline, highlighting the importance of sexual fusion to bloom termination. At Salt Pond, bloom decline also coincided with a dramatic rise in infections by the parasite genus Amoebophrya. The samples that were most heavily infected contained many large cells with higher DNA-associated fluorescence than 2C vegetative cells, but these cells' nuclei were also frequently consumed by Amoebophrya trophonts. Neither large cell size nor increased DNA-associated fluorescence could be replicated by infecting an A. fundyense culture of vegetative cells. Therefore, we attribute these characteristics of the large Salt Pond cells to planozygote maturation rather than Amoebophrya infection, though an interaction between infection and planozygote maturation may also have contributed. The modified IFCB is a valuable tool for exploring the conditions that promote sexual transitions by dinoflagellate blooms but care is needed when interpreting results from samples in which parasitism is prevalent.

Metagenomic analysis of size-fractionated picoplankton in a marine oxygen minimum zone

PubMed Central

Ganesh, Sangita; Parris, Darren J; DeLong, Edward F; Stewart, Frank J

2014-01-01

Marine oxygen minimum zones (OMZs) support diverse microbial communities with roles in major elemental cycles. It is unclear how the taxonomic composition and metabolism of OMZ microorganisms vary between particle-associated and free-living size fractions. We used amplicon (16S rRNA gene) and shotgun metagenome sequencing to compare microbial communities from large (>1.6 μm) and small (0.2–1.6 μm) filter size fractions along a depth gradient in the OMZ off Chile. Despite steep vertical redox gradients, size fraction was a significantly stronger predictor of community composition compared to depth. Phylogenetic diversity showed contrasting patterns, decreasing towards the anoxic OMZ core in the small size fraction, but exhibiting maximal values at these depths within the larger size fraction. Fraction-specific distributions were evident for key OMZ taxa, including anammox planctomycetes, whose coding sequences were enriched up to threefold in the 0.2–1.6 μm community. Functional gene composition also differed between fractions, with the >1.6 μm community significantly enriched in genes mediating social interactions, including motility, adhesion, cell-to-cell transfer, antibiotic resistance and mobile element activity. Prokaryotic transposase genes were three to six fold more abundant in this fraction, comprising up to 2% of protein-coding sequences, suggesting that particle surfaces may act as hotbeds for transposition-based genome changes in marine microbes. Genes for nitric and nitrous oxide reduction were also more abundant (three to seven fold) in the larger size fraction, suggesting microniche partitioning of key denitrification steps. These results highlight an important role for surface attachment in shaping community metabolic potential and genome content in OMZ microorganisms. PMID:24030599

Metagenomic analysis of size-fractionated picoplankton in a marine oxygen minimum zone.

PubMed

Ganesh, Sangita; Parris, Darren J; DeLong, Edward F; Stewart, Frank J

2014-01-01

Marine oxygen minimum zones (OMZs) support diverse microbial communities with roles in major elemental cycles. It is unclear how the taxonomic composition and metabolism of OMZ microorganisms vary between particle-associated and free-living size fractions. We used amplicon (16S rRNA gene) and shotgun metagenome sequencing to compare microbial communities from large (>1.6 μm) and small (0.2-1.6 μm) filter size fractions along a depth gradient in the OMZ off Chile. Despite steep vertical redox gradients, size fraction was a significantly stronger predictor of community composition compared to depth. Phylogenetic diversity showed contrasting patterns, decreasing towards the anoxic OMZ core in the small size fraction, but exhibiting maximal values at these depths within the larger size fraction. Fraction-specific distributions were evident for key OMZ taxa, including anammox planctomycetes, whose coding sequences were enriched up to threefold in the 0.2-1.6 μm community. Functional gene composition also differed between fractions, with the >1.6 μm community significantly enriched in genes mediating social interactions, including motility, adhesion, cell-to-cell transfer, antibiotic resistance and mobile element activity. Prokaryotic transposase genes were three to six fold more abundant in this fraction, comprising up to 2% of protein-coding sequences, suggesting that particle surfaces may act as hotbeds for transposition-based genome changes in marine microbes. Genes for nitric and nitrous oxide reduction were also more abundant (three to seven fold) in the larger size fraction, suggesting microniche partitioning of key denitrification steps. These results highlight an important role for surface attachment in shaping community metabolic potential and genome content in OMZ microorganisms.

Engineering temporal accumulation of a low recalcitrance polysaccharide leads to increased C6 sugar content in plant cell walls.

PubMed

Vega-Sánchez, Miguel E; Loqué, Dominique; Lao, Jeemeng; Catena, Michela; Verhertbruggen, Yves; Herter, Thomas; Yang, Fan; Harholt, Jesper; Ebert, Berit; Baidoo, Edward E K; Keasling, Jay D; Scheller, Henrik V; Heazlewood, Joshua L; Ronald, Pamela C

2015-09-01

Reduced cell wall recalcitrance and increased C6 monosaccharide content are desirable traits for future biofuel crops, as long as these biomass modifications do not significantly alter normal growth and development. Mixed-linkage glucan (MLG), a cell wall polysaccharide only present in grasses and related species among flowering plants, is comprised of glucose monomers linked by both β-1,3 and β-1,4 bonds. Previous data have shown that constitutive production of MLG in barley (Hordeum vulgare) severely compromises growth and development. Here, we used spatio-temporal strategies to engineer Arabidopsis thaliana plants to accumulate significant amounts of MLG in the cell wall by expressing the rice CslF6 MLG synthase using secondary cell wall and senescence-associated promoters. Results using secondary wall promoters were suboptimal. When the rice MLG synthase was expressed under the control of a senescence-associated promoter, we obtained up to four times more glucose in the matrix cell wall fraction and up to a 42% increase in saccharification compared to control lines. Importantly, these plants grew and developed normally. The induction of MLG deposition at senescence correlated with an increase of gluconic acid in cell wall extracts of transgenic plants in contrast to the other approaches presented in this study. MLG produced in Arabidopsis has an altered structure compared to the grass glucan, which likely affects its solubility, while its molecular size is unaffected. The induction of cell wall polysaccharide biosynthesis in senescing tissues offers a novel engineering alternative to enhance cell wall properties of lignocellulosic biofuel crops. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

The relationships among IGF-1, DNA content, and protein accumulation during skeletal muscle hypertrophy

NASA Technical Reports Server (NTRS)

Adams, G. R.; Haddad, F.

1996-01-01

Insulin-like growth factor-1 (IGF-1) is known to have anabolic effects on skeletal muscle cells. This study examined the time course of muscle hypertrophy and associated IGF-1 peptide and mRNA expression. Data were collected at 3, 7, 14, and 28 days after surgical removal of synergistic muscles of both normal and hypophysectomized (HX) animals. Overloading increased the plantaris (Plant) mass, myofiber size, and protein-to-body weight ratio in both groups (normal and HX; P < 0.05). Muscle IGF-1 peptide levels peaked at 3 (normal) and 7 (HX) days of overloading with maximum 4.1-fold (normal) and 6.2-fold (HX) increases. Increases in muscle IGF-1 preceded the hypertrophic response. Total DNA content of the overloaded Plant increased in both groups. There was a strong positive relationship between IGF-1 peptide and DNA content in the overloaded Plant from both groups. These results indicate that 1) the muscles from rats with both normal and severely depressed systemic levels of IGF-1 respond to functional overload with an increase in local IGF-1 expression and 2) this elevated IGF-1 may be contributing to the hypertrophy response, possibly via the mobilization of satellite cells to provide increases in muscle DNA.

Directed evolution of cell size in Escherichia coli.

PubMed

Yoshida, Mari; Tsuru, Saburo; Hirata, Naoko; Seno, Shigeto; Matsuda, Hideo; Ying, Bei-Wen; Yomo, Tetsuya

2014-12-17

In bacteria, cell size affects chromosome replication, the assembly of division machinery, cell wall synthesis, membrane synthesis and ultimately growth rate. In addition, cell size can also be a target for Darwinian evolution for protection from predators. This strong coupling of cell size and growth, however, could lead to the introduction of growth defects after size evolution. An important question remains: can bacterial cell size change and/or evolve without imposing a growth burden? The directed evolution of particular cell sizes, without a growth burden, was tested with a laboratory Escherichia coli strain. Cells of defined size ranges were collected by a cell sorter and were subsequently cultured. This selection-propagation cycle was repeated, and significant changes in cell size were detected within 400 generations. In addition, the width of the size distribution was altered. The changes in cell size were unaccompanied by a growth burden. Whole genome sequencing revealed that only a few mutations in genes related to membrane synthesis conferred the size evolution. In conclusion, bacterial cell size could evolve, through a few mutations, without growth reduction. The size evolution without growth reduction suggests a rapid evolutionary change to diverse cell sizes in bacterial survival strategies.

Influence of rare earth content on Mm-based AB 5 metal hydride alloys for Ni-MH batteries-An X-ray fluorescence study

NASA Astrophysics Data System (ADS)

Ananth, M. V.; Raju, M.; Manimaran, K.; Balachandran, G.; Nair, Lekshmi M.

AB 5-type MH alloys with Mm (Misch metal) as the A part (with varied rare earth contents in Mm) were investigated for rare earth by XRF analysis and battery performance by life cycle tests with an objective of understanding the influence of rare earth content on electrochemical hydrogen storage. The La/Ce ratio was found to vary from 0.51 to 18.73. The capacity output varied between 179 and 266 mAh g -1. The results show that the La/Ce ratio has a strong influence on the performance, with the best performance realized with samples having an La/Ce ratio of around 12. La enhancement facilitates easy activation due to refinement in grain size and interstitial dimensions. Also, an orderly influence on crystalline structure could be seen. The study demonstrates that the rare earth content is an essential factor in determining the maximum capacity output because of its influence on crystal orientation as well as an increase in the radius of the interstitials, lattice constants and cell volumes.

High-Content Microscopy Analysis of Subcellular Structures: Assay Development and Application to Focal Adhesion Quantification.

PubMed

Kroll, Torsten; Schmidt, David; Schwanitz, Georg; Ahmad, Mubashir; Hamann, Jana; Schlosser, Corinne; Lin, Yu-Chieh; Böhm, Konrad J; Tuckermann, Jan; Ploubidou, Aspasia

2016-07-01

High-content analysis (HCA) converts raw light microscopy images to quantitative data through the automated extraction, multiparametric analysis, and classification of the relevant information content. Combined with automated high-throughput image acquisition, HCA applied to the screening of chemicals or RNAi-reagents is termed high-content screening (HCS). Its power in quantifying cell phenotypes makes HCA applicable also to routine microscopy. However, developing effective HCA and bioinformatic analysis pipelines for acquisition of biologically meaningful data in HCS is challenging. Here, the step-by-step development of an HCA assay protocol and an HCS bioinformatics analysis pipeline are described. The protocol's power is demonstrated by application to focal adhesion (FA) detection, quantitative analysis of multiple FA features, and functional annotation of signaling pathways regulating FA size, using primary data of a published RNAi screen. The assay and the underlying strategy are aimed at researchers performing microscopy-based quantitative analysis of subcellular features, on a small scale or in large HCS experiments. © 2016 by John Wiley & Sons, Inc. Copyright © 2016 John Wiley & Sons, Inc.

In vitro effects of coal fly ashes: hydroxyl radical generation, iron release, and DNA damage and toxicity in rat lung epithelial cells

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

van Maanen, J.M.; Borm, P.J.; Knaapen, A

1999-12-15

The authors measured iron release, acellular generation of hydroxyl radicals, and oxidative DNA damage and cytotoxicity in rat lung epithelial (RLE) cells by different coal fly ashes (CFA) that contain both quartz and iron. Seven samples of CFA with different particle size and quartz content (up to 14.1%) were tested along with silica (alpha-quartz), ground coal, and coal mine dust (respirable) as positive control particles, and fine TiO{sub 2} (anatase) as a negative control. Five test samples were pulverized fuel ashes (PFA), two samples were coal gasification (SCG) ashes (quartz content {lt} 0.1%), and one sample was a ground coal.more » No marked differences between SCG and PFA fly ashes were observed, and toxicity did not correlate with physicochemical characteristics or effect parameters. Stable surface radicals were only detected in the reference particles silica and coal mine dust, but not in CFA. On the other hand, hydroxyl radical generation by all fly ashes was observed in the presence of hydrogen peroxide. Also a relationship between acellular hydroxyl radical generation and oxidative DNA damage in RLE cells by CFA was observed. The respirable ashes (MAT023, 38, and 41) showed an extensive level of hydroxyl radical generation in comparison to nonrespirable fly ashes and respirable references. This was related to the iron mobilization from these particles. Themechanisms by which CFA and the positive references (silica, coal mine dust) affect rat lung epithelial cells seem to be different, and the data suggest that quartz in CFA does not act the same as quartz in silica or coal mine dust. However, the results indicate an important role for size and iron release in generation and subsequent effects of reactive oxygen species caused by CFA.« less

Effects of endomorphin-1 postconditioning on myocardial ischemia/reperfusion injury and myocardial cell apoptosis in a rat model.

PubMed

Zhang, Wei-Ping; Zong, Qiao-Feng; Gao, Qin; Yu, Ying; Gu, Xiao-Yu; Wang, Ya; Li, Zheng-Hong; Ge, Min

2016-10-01

Endomorphins (EMs) have important roles in the body with regards to analgesia, feeding behavior, gastrointestinal movement and inflammatory reaction. Recent studies have reported that EMs may also participate in chronic hypoxia in the protection of rat myocardial ischemia/reperfusion; however, the mediator and underlying mechanisms remain to be elucidated. The aim of the present study was to investigate the effects of EM‑1 postconditioning on myocardial ischemia/reperfusion injury (MIRI) and myocardial cell apoptosis in a rat model, and to assess its likely mechanisms. A total of 48 male Sprague Dawley rats were randomly divided into four groups: Sham group, ischemia/reperfusion group (IR group), ischemic postconditioning group (IPO group) and EM‑1 postconditioning group (EM50 group). A MIRI model was established via occlusion of the left anterior descending branch of the coronary artery for 30 min, followed by reperfusion for 120 min in vivo. Hemodynamic indexes were recorded and analyzed. Following reperfusion, plasma lactate dehydrogenase (LDH), creatine kinase‑MB (CK‑MB), malondialdehyde (MDA), superoxide dismutase (SOD), interleukin‑6 (IL‑6) and tumor necrosis factor‑α (TNF‑α) contents or activities were measured, infarct size was determined, and the expression levels of B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) mRNA and cleaved caspase‑3 protein were assessed. In the IR group, mean arterial pressure (MAP) and heart rate (HR) were decreased compared with in the sham group. In addition, LDH and CK‑MB levels were increased; IL‑6, TNF‑α and MDA content was increased; SOD activity was decreased; the Bcl‑2/Bax ratio was decreased; and cleaved caspase‑3 protein expression levels were increased in the IR group. Compared with in the IR group, in the IPO and EM50 groups, MAP and heart rate (HR) were recovered to various extents post‑reperfusion; LDH and CK‑MB levels were decreased; IL‑6, TNF‑α and MDA content was decreased; SOD activity was increased; infarct size was reduced; the Bcl‑2/Bax ratio was increased; and cleaved caspase‑3 protein expression levels were decreased. In conclusion, EM‑1 postconditioning was revealed to reduce I/R injury and inhibit myocardial cell apoptosis, which may be associated with reductions in oxidative stress and inflammatory reactions.

Rigid palm oil-based polyurethane foam reinforced with diamine-modified montmorillonite nanoclay

NASA Astrophysics Data System (ADS)

Haziq Dzulkifli, Mohd; Yazid Yahya, Mohd; Majid, Rohah A.

2017-05-01

This paper presents work on organically-modified montmorillonite (MMT) nanoclay embedded in rigid palm oil-based polyurethane (PU) foam. MMT was modified with organic surfactant diamino propane (DAP). PU foam was fabricated in closed mold, and the amount of DAP-MMT was varied in each foam formulation. The obtained foam was tested for its microstructure and morphology. Appearance of peaks from infra-red spectra corresponding to N-H, C=O, and C-N confirms the formation of PU networks. Scanning electron microscopy (SEM) revealed fine, closed-cellular structure at low clay loading; increasing DAP-MMT content induced larger cell sizes with blowholes. X-ray diffraction (XRD) indicates fully-exfoliated clays at 1 wt. % and partial-exfoliation at 3 wt. % clay loading, suggesting clumping of clays as DAP-MMT content increased.

CRISPR-UMI: single-cell lineage tracing of pooled CRISPR-Cas9 screens.

PubMed

Michlits, Georg; Hubmann, Maria; Wu, Szu-Hsien; Vainorius, Gintautas; Budusan, Elena; Zhuk, Sergei; Burkard, Thomas R; Novatchkova, Maria; Aichinger, Martin; Lu, Yiqing; Reece-Hoyes, John; Nitsch, Roberto; Schramek, Daniel; Hoepfner, Dominic; Elling, Ulrich

2017-12-01

Pooled CRISPR screens are a powerful tool for assessments of gene function. However, conventional analysis is based exclusively on the relative abundance of integrated single guide RNAs (sgRNAs) between populations, which does not discern distinct phenotypes and editing outcomes generated by identical sgRNAs. Here we present CRISPR-UMI, a single-cell lineage-tracing methodology for pooled screening to account for cell heterogeneity. We generated complex sgRNA libraries with unique molecular identifiers (UMIs) that allowed for screening of clonally expanded, individually tagged cells. A proof-of-principle CRISPR-UMI negative-selection screen provided increased sensitivity and robustness compared with conventional analysis by accounting for underlying cellular and editing-outcome heterogeneity and detection of outlier clones. Furthermore, a CRISPR-UMI positive-selection screen uncovered new roadblocks in reprogramming mouse embryonic fibroblasts as pluripotent stem cells, distinguishing reprogramming frequency and speed (i.e., effect size and probability). CRISPR-UMI boosts the predictive power, sensitivity, and information content of pooled CRISPR screens.

Synthesis, Characterization, and Preliminary Investigation of Cell Interaction of Magnetic Nanoparticles with Catechol-Containing Shells

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

Wagner, Kerstin; Seemann, Thomas; Wyrwa, Ralf

2010-12-02

Superparamagnetic iron oxide cores were synthesized by co-precipitation of Fe(II) and Fe(III) salts and subsequently stabilized by coating with different catechols (levodopa, dopamine, hydrocaffeic acid, dopamine-containing carboxymethyl dextran) known to act as high-affinity, bidentate ligands for Fe(III). The prepared stable magnetic fluids were characterized with regard to their chemical composition (content of iron and shell material, Fe(II)/Fe(III) ratio) and their physical properties (size, surface charge, magnetic parameters). The nanoparticles showed no or only slight cytotoxic effects within 1 and 4 days of incubation with 3T3 fibroblast cells. Preliminary experiments were performed to study the interaction of the prepared nanoparticles withmore » human MCF-7 breast cancer cells and leukocytes. An intense interaction of the MCF-7 cells with these particles was found whereas the leukocytes showed a lower tendency of interaction. Based on these finding, the novel magnetic nanoparticles possess the potential for use in depletion of tumor cells from peripheral blood.« less

An Oil-Stream Photomicrographic Aeroscope for Obtaining Cloud Liquid-Water Content and Droplet Size Distributions in Flight

NASA Technical Reports Server (NTRS)

Hacker, Paul T.

1956-01-01

An airborne cloud aeroscope by which droplet size, size distribution, and liquid-water content of clouds can be determined has been developed and tested in flight and in wind tunnels with water sprays. In this aeroscope the cloud droplets are continuously captured in a stream of oil, which Is then photographed by a photomicrographic camera. The droplet size and size distribution can be determined directly from the photographs. With the droplet size distribution known, the liquid-water content of the cloud can be computed from the geometry of the aeroscope, the airspeed, and the oil-flow rate. The aeroscope has the following features: Data are obtained semi-automatically, and permanent data are taken in the form of photographs. A single picture usually contains a sufficient number of droplets to establish the droplet size distribution. Cloud droplets are continuously captured in the stream of oil, but pictures are taken at Intervals. The aeroscope can be operated in icing and non-icing conditions. Because of mixing of oil in the instrument, the droplet-distribution patterns and liquid-water content values from a single picture are exponentially weighted average values over a path length of about 3/4 mile at 150 miles per hour. The liquid-water contents, volume-median diameters, and distribution patterns obtained on test flights and in the Lewis icing tunnel are similar to previously published data.

Navy bean flour particle size and protein content affect cake baking and batter quality

USDA-ARS?s Scientific Manuscript database

Whole navy bean flour and its fine and coarse particle size fractions were used to completely replace wheat flour in cakes. Replacement of wheat flour with whole bean flour significantly increased the protein content. The protein content was adjusted to three levels with navy bean starch. The effect...

The Ectopic Expression of the Wheat Puroindoline Genes Increase Germ Size and Seed Oil Content in Transgenic Corn

PubMed Central

Zhang, Jinrui; Martin, John M.; Beecher, Brian; Lu, Chaofu; Hannah, L. Curtis; Wall, Michael L.; Altosaar, Illimar; Giroux, Michael J.

2014-01-01

Plant oil content and composition improvement is a major goal of plant breeding and biotechnology. The Puroindoline a and b (PINA and PINB) proteins together control whether wheat seeds are soft or hard textured and share a similar structure to that of plant non-specific lipid-transfer proteins. Here we transformed corn (Zea mays L.) with the wheat (Triticum aestivum L.) puroindoline genes (Pina and Pinb) to assess their effects upon seed oil content and quality. Pina and Pinb coding sequences were introduced into corn under the control of a corn Ubiquitin promoter. Three Pina/Pinb expression positive transgenic events were evaluated over two growing seasons. The results showed that Pin expression increased germ size significantly without negatively impacting seed size. Germ yield increased 33.8% while total seed oil content was increased by 25.23%. Seed oil content increases were primarily the result of increased germ size. This work indicates that higher oil content corn hybrids having increased food or feed value could be produced via puroindoline expression. PMID:20725765

Ecological and evolutionary significance of genomic GC content diversity in monocots

PubMed Central

Šmarda, Petr; Bureš, Petr; Horová, Lucie; Leitch, Ilia J.; Mucina, Ladislav; Pacini, Ettore; Tichý, Lubomír; Grulich, Vít; Rotreklová, Olga

2014-01-01

Genomic DNA base composition (GC content) is predicted to significantly affect genome functioning and species ecology. Although several hypotheses have been put forward to address the biological impact of GC content variation in microbial and vertebrate organisms, the biological significance of GC content diversity in plants remains unclear because of a lack of sufficiently robust genomic data. Using flow cytometry, we report genomic GC contents for 239 species representing 70 of 78 monocot families and compare them with genomic characters, a suite of life history traits and climatic niche data using phylogeny-based statistics. GC content of monocots varied between 33.6% and 48.9%, with several groups exceeding the GC content known for any other vascular plant group, highlighting their unusual genome architecture and organization. GC content showed a quadratic relationship with genome size, with the decreases in GC content in larger genomes possibly being a consequence of the higher biochemical costs of GC base synthesis. Dramatic decreases in GC content were observed in species with holocentric chromosomes, whereas increased GC content was documented in species able to grow in seasonally cold and/or dry climates, possibly indicating an advantage of GC-rich DNA during cell freezing and desiccation. We also show that genomic adaptations associated with changing GC content might have played a significant role in the evolution of the Earth’s contemporary biota, such as the rise of grass-dominated biomes during the mid-Tertiary. One of the major selective advantages of GC-rich DNA is hypothesized to be facilitating more complex gene regulation. PMID:25225383

Analysis of Cellular DNA Content by Flow Cytometry.

PubMed

Darzynkiewicz, Zbigniew; Huang, Xuan; Zhao, Hong

2017-10-02

Cellular DNA content can be measured by flow cytometry with the aim of : (1) revealing cell distribution within the major phases of the cell cycle, (2) estimating frequency of apoptotic cells with fractional DNA content, and/or (3) disclosing DNA ploidy of the measured cell population. In this unit, simple and universally applicable methods for staining fixed cells are presented, as are methods that utilize detergents and/or proteolytic treatment to permeabilize cells and make DNA accessible to fluorochrome. Additionally, supravital cell staining with Hoechst 33342, which is primarily used for sorting live cells based on DNA-content differences for their subsequent culturing, is described. Also presented are methods for staining cell nuclei isolated from paraffin-embedded tissues. Available algorithms are listed for deconvolution of DNA-content-frequency histograms to estimate percentage of cells in major phases of the cell cycle and frequency of apoptotic cells with fractional DNA content. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley and Sons, Inc.

Analysis of Cellular DNA Content by Flow Cytometry.

PubMed

Darzynkiewicz, Zbigniew; Huang, Xuan; Zhao, Hong

2017-11-01

Cellular DNA content can be measured by flow cytometry with the aim of : (1) revealing cell distribution within the major phases of the cell cycle, (2) estimating frequency of apoptotic cells with fractional DNA content, and/or (3) disclosing DNA ploidy of the measured cell population. In this unit, simple and universally applicable methods for staining fixed cells are presented, as are methods that utilize detergents and/or proteolytic treatment to permeabilize cells and make DNA accessible to fluorochrome. Additionally, supravital cell staining with Hoechst 33342, which is primarily used for sorting live cells based on DNA-content differences for their subsequent culturing, is described. Also presented are methods for staining cell nuclei isolated from paraffin-embedded tissues. Available algorithms are listed for deconvolution of DNA-content-frequency histograms to estimate percentage of cells in major phases of the cell cycle and frequency of apoptotic cells with fractional DNA content. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley and Sons, Inc.

Tripolar acytokinetic mitosis and formation of feto-maternal syncytia in the bovine placentome: different modes of the generation of multinuclear cells.

PubMed

Klisch, K; Pfarrer, C; Schuler, G; Hoffmann, B; Leiser, R

1999-08-01

The vast majority of trophoblast giant cells in the ruminant placenta are binuclear and are believed to derive from mononuclear trophoblastic cells by a single acytokinetic mitosis. There is no satisfactory explanation for the generation of the small proportion of trophoblast giant cells with one, three, or more nuclei. In this light-and electronmicroscopic study of bovine placentomal tissue from the second half of gestation, developmental stages of the trophoblast giant cells are investigated. Large mitotic figures indicate mitotic polyploidization, which is proposed to be due to two subsequent acytokinetic mitoses. Tripolar mitoses offer an explanation for the development of trinucleate trophoblast giant cells. Measurements of nuclear volumes in a series of semithin sections revealed that three size classes of trophoblast giant cells occur. The approximately doubling of nuclear volume between each class is thought to reflect different levels of DNA content that result from polyploidization in this cell type. Although trinuclear feto-maternal hybrid cells are the standard outcome of the fusion of binuclear trophoblast giant cells with uterine epithelial cells, some syncytia with at least five nuclei were observed in the uterine epithelium.

Particle size fractionation as a method for characterizing the nutrient content of municipal green waste used for composting.

PubMed

Haynes, R J; Belyaeva, O N; Zhou, Y-F

2015-01-01

In order to better characterize mechanically shredded municipal green waste used for composting, five samples from different origins were separated into seven particle size fractions (>20mm, 10-20mm, 5-10mm, 2-5mm, 1-2mm, 0.5-1.0mm and <0.5mm diameter) and analyzed for organic C and nutrient content. With decreasing particle size there was a decrease in organic C content and an increase in macronutrient, micronutrient and ash content. This reflected a concentration of lignified woody material in the larger particle fractions and of green stems and leaves and soil in the smaller particle sizes. The accumulation of nutrients in the smaller sized fractions means the practice of using large particle sizes for green fuel and/or mulch does not greatly affect nutrient cycling via green waste composting. During a 100-day incubation experiment, using different particle size fractions of green waste, there was a marked increase in both cumulative CO2 evolution and mineral N accumulation with decreasing particle size. Results suggested that during composting of bulk green waste (with a high initial C/N ratio such as 50:1), mineral N accumulates because decomposition and net N immobilization in larger particles is slow while net N mineralization proceeds rapidly in the smaller (<1mm dia.) fractions. Initially, mineral N accumulated in green waste as NH4(+)-N, but over time, nitrification proceeded resulting in accumulation of NO3(-)-N. It was concluded that the nutrient content, N mineralization potential and decomposition rate of green waste differs greatly among particle size fractions and that chemical analysis of particle size fractions provides important additional information over that of a bulk sample. Copyright © 2014 Elsevier Ltd. All rights reserved.

Low-load resistance exercise during inactivity is associated with greater fibre area and satellite cell expression in older skeletal muscle.

PubMed

Moore, Daniel R; Kelly, Ryan P; Devries, Michaela C; Churchward-Venne, Tyler A; Phillips, Stuart M; Parise, Gianni; Johnston, Adam P

2018-05-14

Age-related sarcopenia is accelerated by physical inactivity. Low-load resistance exercise (LLRE) counters inactivity-induced muscle atrophy in older adults, but changes in muscle fibre morphology are unstudied. We aimed to determine the impact of LLRE during short-term inactivity (step-reduction) on muscle fibre size and capillarity as well as satellite cell (SC) content in older skeletal muscle. Fourteen older (~71 years) male adults underwent 14 days of step reduction (<1500 steps/day) while performing six sessions of LLRE (~30% maximal strength) with one leg (SR + EX) while the contralateral leg served as an untrained control (SR). Seven healthy ambulatory age-matched male adults (~69 years) served as a comparator group (COM). Muscle biopsies were taken from the vastus lateralis after 14 days, and immunohistochemical analysis was performed to determine muscle fibre cross-sectional area (CSA), myonuclear content, SC content (PAX7 + cells), and total (C:F) and fibre type-specific (C:Fi) capillary-to-fibre ratios. Type I and II fibre CSA was greater in SR + EX compared with SR. Whereas there were no differences across fibre types between SR + EX and CON, type II fibre CSA was significantly lower in SR compared with COM. Type II myonuclear domain was greater in SR + EX compared with COM and SR. Pax7 + cells associated with type I and II fibres were lower in SR compared with SR + EX. Type II PAX7+ cells were also lower in SR compared with COM with a similar trend for type I fibres. There were trends for a lower C:Fi in SR compared with SR + EX for both fibre types with no differences for each compared with COM. Minimal LLRE during a period of decreased physical activity is associated with greater muscle fibre CSA, SC content, and capillarization. These results support the use of LLRE as an effective countermeasure to inactivity-induced alterations in muscle morphology with age. © 2018 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

Cell Painting, a high-content image-based assay for morphological profiling using multiplexed fluorescent dyes

PubMed Central

Bray, Mark-Anthony; Singh, Shantanu; Han, Han; Davis, Chadwick T.; Borgeson, Blake; Hartland, Cathy; Kost-Alimova, Maria; Gustafsdottir, Sigrun M.; Gibson, Christopher C.; Carpenter, Anne E.

2016-01-01

In morphological profiling, quantitative data are extracted from microscopy images of cells to identify biologically relevant similarities and differences among samples based on these profiles. This protocol describes the design and execution of experiments using Cell Painting, a morphological profiling assay multiplexing six fluorescent dyes imaged in five channels, to reveal eight broadly relevant cellular components or organelles. Cells are plated in multi-well plates, perturbed with the treatments to be tested, stained, fixed, and imaged on a high-throughput microscope. Then, automated image analysis software identifies individual cells and measures ~1,500 morphological features (various measures of size, shape, texture, intensity, etc.) to produce a rich profile suitable for detecting subtle phenotypes. Profiles of cell populations treated with different experimental perturbations can be compared to suit many goals, such as identifying the phenotypic impact of chemical or genetic perturbations, grouping compounds and/or genes into functional pathways, and identifying signatures of disease. Cell culture and image acquisition takes two weeks; feature extraction and data analysis take an additional 1-2 weeks. PMID:27560178

[Autoradiographic study of the renewal rate of neutrophils and thrombocytes in summer and winter frogs].

PubMed

Goryshina, E N

1984-04-01

In early August frogs were injected with 3H-thymidine and observed during 10 months under conditions close to natural. Individual changes of neutrophil and thrombocyte contents in the blood, those of the number of labeled cells among them, and the density of labeling were studied. The life span of neutrophils in the active frogs was found as long as 2-3 weeks, while that of thrombocytes lasted for several months. In September the hibernating cell populations are formed and cell proliferation ceases. This process is suggested to be regulated by some complex centralized mechanisms rather than by a direct action of temperature. The size of circulating populations of both the cell types decreases during hibernation, part of the cells is deposited outside of circulation. The life span of cells rises considerably, their renewal begins only in spring. The ability of cells of the neutrophilic lineage to proliferate is preserved at low temperatures and is realized in pathological conditions. The similarities in seasonal adaptations are stated between amphibians and hibernating mammals at the level of cellular populations.

Cancer stem cells and cell size: A causal link?

PubMed

Li, Qiuhui; Rycaj, Kiera; Chen, Xin; Tang, Dean G

2015-12-01

The majority of normal animal cells are 10-20 μm in diameter. Many signaling mechanisms, notably PI3K/Akt/mTOR, Myc, and Hippo pathways, tightly control and coordinate cell growth, cell size, cell division, and cell number during homeostasis. These regulatory mechanisms are frequently deregulated during tumorigenesis resulting in wide variations in cell sizes and increased proliferation in cancer cells. Here, we first review the evidence that primitive stem cells in adult tissues are quiescent and generally smaller than their differentiated progeny, suggesting a correlation between small cell sizes with the stemness. Conversely, increased cell size positively correlates with differentiation phenotypes. We then discuss cancer stem cells (CSCs) and present some evidence that correlates cell sizes with CSC activity. Overall, a causal link between CSCs and cell size is relatively weak and remains to be rigorously assessed. In the future, optimizing methods for isolating cells based on size should help elucidate the connection between cancer cell size and CSC characteristics. Copyright © 2015 Elsevier Ltd. All rights reserved.

Analysis of hard coal quality for narrow size fraction under 20 mm

NASA Astrophysics Data System (ADS)

Niedoba, Tomasz; Pięta, Paulina

2018-01-01

The paper presents the results of an analysis of hard coal quality diversion in narrow size fraction by using taxonomic methods. Raw material samples were collected in selected mines of Upper Silesian Industrial Region and they were classified according to the Polish classification as types 31, 34.2 and 35. Then, each size fraction was characterized in terms of the following properties: density, ash content, calorific content, volatile content, total sulfur content and analytical moisture. As a result of the analysis it can be stated that the best quality in the entire range of the tested size fractions was the 34.2 coking coal type. At the same time, in terms of price parameters, high quality of raw material characterised the following size fractions: 0-6.3 mm of 31 energetic coal type and 0-3.15 mm of 35 coking coal type. The methods of grouping (Ward's method) and agglomeration (k-means method) have shown that the size fraction below 10 mm was characterized by higher quality in all the analyzed hard coal types. However, the selected taxonomic methods do not make it possible to identify individual size fraction or hard coal types based on chosen parameters.

Complexities of bloom dynamics in the toxic dinoflagellate Alexandrium fundyense revealed through DNA measurements by imaging flow cytometry coupled with species-specific rRNA probes

PubMed Central

Brosnahan, Michael L.; Farzan, Shahla; Keafer, Bruce A.; Sosik, Heidi M.; Olson, Robert J.; Anderson, Donald M.

2013-01-01

Measurements of the DNA content of different protist populations can shed light on a variety of processes, including cell division, sex, prey ingestion, and parasite invasion. Here, we modified an Imaging FlowCytobot (IFCB), a custom-built flow cytometer that records images of microplankton, to measure the DNA content of large dinoflagellates and other high-DNA content species. The IFCB was also configured to measure fluorescence from Cy3-labeled rRNA probes, aiding the identification of Alexandrium fundyense (syn. A. tamarense Group I), a photosynthetic dinoflagellate that causes paralytic shellfish poisoning (PSP). The modified IFCB was used to analyze samples from the development, peak and termination phases of an inshore A. fundyense bloom (Salt Pond, Eastham, MA USA), and from a rare A. fundyense ‘red tide’ that occurred in the western Gulf of Maine, offshore of Portsmouth, NH (USA). Diploid or G2 phase (‘2C’) A. fundyense cells were frequently enriched at the near-surface, suggesting an important role for aggregation at the air-sea interface during sexual events. Also, our analysis showed that large proportions of A. fundyense cells in both the Salt Pond and red tide blooms were planozygotes during bloom decline, highlighting the importance of sexual fusion to bloom termination. At Salt Pond, bloom decline also coincided with a dramatic rise in infections by the parasite genus Amoebophrya. The samples that were most heavily infected contained many large cells with higher DNA-associated fluorescence than 2C vegetative cells, but these cells’ nuclei were also frequently consumed by Amoebophrya trophonts. Neither large cell size nor increased DNA-associated fluorescence could be replicated by infecting an A. fundyense culture of vegetative cells. Therefore we attribute these characteristics of the large Salt Pond cells to planozygote maturation rather than Amoebophrya infection, though an interaction between infection and planozygote maturation may also have contributed. The modified IFCB is a valuable tool for exploring the conditions that promote sexual transitions by dinoflagellate blooms but care is needed when interpreting results from samples in which parasitism is prevalent. PMID:24891769

Constitutive nuclear lamina-genome interactions are highly conserved and associated with A/T-rich sequence.

PubMed

Meuleman, Wouter; Peric-Hupkes, Daan; Kind, Jop; Beaudry, Jean-Bernard; Pagie, Ludo; Kellis, Manolis; Reinders, Marcel; Wessels, Lodewyk; van Steensel, Bas

2013-02-01

In metazoans, the nuclear lamina is thought to play an important role in the spatial organization of interphase chromosomes, by providing anchoring sites for large genomic segments named lamina-associated domains (LADs). Some of these LADs are cell-type specific, while many others appear constitutively associated with the lamina. Constitutive LADs (cLADs) may contribute to a basal chromosome architecture. By comparison of mouse and human lamina interaction maps, we find that the sizes and genomic positions of cLADs are strongly conserved. Moreover, cLADs are depleted of synteny breakpoints, pointing to evolutionary selective pressure to keep cLADs intact. Paradoxically, the overall sequence conservation is low for cLADs. Instead, cLADs are universally characterized by long stretches of DNA of high A/T content. Cell-type specific LADs also tend to adhere to this "A/T rule" in embryonic stem cells, but not in differentiated cells. This suggests that the A/T rule represents a default positioning mechanism that is locally overruled during lineage commitment. Analysis of paralogs suggests that during evolution changes in A/T content have driven the relocation of genes to and from the nuclear lamina, in tight association with changes in expression level. Taken together, these results reveal that the spatial organization of mammalian genomes is highly conserved and tightly linked to local nucleotide composition.

Exosome proteomics reveals transcriptional regulator proteins with potential to mediate downstream pathways.

PubMed

Ung, Timothy H; Madsen, Helen J; Hellwinkel, Justin E; Lencioni, Alex M; Graner, Michael W

2014-11-01

Exosomes are virus-sized, membrane-enclosed vesicles with origins in the cellular endosomal system, but are released extracellularly. As a population, these tiny vesicles carry relatively enormous amounts of information in their protein, lipid and nucleic acid content, and the vesicles can have profound impacts on recipient cells. This review employs publically-available data combined with gene ontology applications to propose a novel concept, that exosomes transport transcriptional and translational machinery that may have direct impacts on gene expression in recipient cells. Here, we examine the previously published proteomic contents of medulloblastoma-derived exosomes, focusing on transcriptional regulators; we found that there are numerous proteins that may have potential roles in transcriptional and translational regulation with putative influence on downstream, cancer-related pathways. We expanded this search to all of the proteins in the Vesiclepedia database; using gene ontology approaches, we see that these regulatory factors are implicated in many of the processes involved in cancer initiation and progression. This information suggests that some of the effects of exosomes on recipient cells may be due to the delivery of protein factors that can directly and fundamentally change the transcriptional landscape of the cells. Within a tumor environment, this has potential to tilt the advantage towards the cancer. © 2014 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

Localised controlled release of simvastatin from porous chitosan-gelatin scaffolds engrafted with simvastatin loaded PLGA-microparticles for bone tissue engineering application.

PubMed

Gentile, Piergiorgio; Nandagiri, Vijay Kumar; Daly, Jacqueline; Chiono, Valeria; Mattu, Clara; Tonda-Turo, Chiara; Ciardelli, Gianluca; Ramtoola, Zebunnissa

2016-02-01

Localised controlled release of simvastatin from porous freeze-dried chitosan-gelatin (CH-G) scaffolds was investigated by incorporating simvastatin loaded poly-(dl-lactide-co-glycolide) acid (PLGA) microparticles (MSIMs) into the scaffolds. MSIMs at 10% w/w simvastatin loading were prepared using a single emulsion-solvent evaporation method. The MSIM optimal amount to be incorporated into the scaffolds was selected by analysing the effect of embedding increasing amounts of blank PLGA microparticles (BL-MPs) on the scaffold physical properties and on the in vitro cell viability using a clonal human osteoblastic cell line (hFOB). Increasing the BL-MP content from 0% to 33.3% w/w showed a significant decrease in swelling degree (from 1245±56% to 570±35%). Scaffold pore size and distribution changed significantly as a function of BL-MP loading. Compressive modulus of scaffolds increased with increasing BL-MP amount up to 16.6% w/w (23.0±1.0kPa). No significant difference in cell viability was observed with increasing BL-MP loading. Based on these results, a content of 16.6% w/w MSIM particles was incorporated successfully in CH-G scaffolds, showing a controlled localised release of simvastatin able to influence the hFOB cell proliferation and the osteoblastic differentiation after 11 days. Copyright © 2015 Elsevier B.V. All rights reserved.

Myeloid Kdm6b deficiency results in advanced atherosclerosis.

PubMed

Neele, Annette E; Gijbels, Marion J J; van der Velden, Saskia; Hoeksema, Marten A; Boshuizen, Marieke C S; Prange, Koen H M; Chen, Hung-Jen; Van den Bossche, Jan; van Roomen, Cindy P P A; Shami, Annelie; Levels, Johannes H M; Kroon, Jeffrey; Lucas, Tina; Dimmeler, Stefanie; Lutgens, Esther; de Winther, Menno P J

2018-06-01

Atherosclerosis is a lipid-driven chronic inflammatory disorder of the arteries, and monocytes and macrophages play a central role in this process. Within the atherosclerotic lesion, macrophages can scavenge modified lipids and become the so-called foam cells. We previously reported that the epigenetic enzyme Kdm6b (also known as Jmjd3) controls the pro-fibrotic transcriptional profile of peritoneal foam cells. Given the importance of these cells in atherosclerosis, we now studied the effect of myeloid Kdm6b on disease progression. Bone marrow of myeloid Kdm6b deficient (Kdm6b del ) mice or wild type littermates (Kdm6b wt ) was transplanted to lethally irradiated Ldlr -/- mice fed a high fat diet for 9 weeks to induce atherosclerosis. Lesion size was similar in Kdm6b wt and Kdm6b del transplanted mice. However, lesions of Kdm6b del mice contained more collagen and were more necrotic. Pathway analysis on peritoneal foam cells showed that the pathway involved in leukocyte chemotaxis was most significantly upregulated. Although macrophage and neutrophil content was similar after 9 weeks of high fat diet feeding, the relative increase in collagen content and necrosis revealed that atherosclerotic lesions in Kdm6b del mice progress faster. Myeloid Kdm6b deficiency results in more advanced atherosclerosis. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Melatonin-loaded lecithin/chitosan nanoparticles: physicochemical characterisation and permeability through Caco-2 cell monolayers.

PubMed

Hafner, Anita; Lovrić, Jasmina; Voinovich, Dario; Filipović-Grcić, Jelena

2009-11-03

In this study, the potential of lecithin/chitosan nanoparticles (NPs) as a mucoadhesive colloidal nanosystem for transmucosal delivery of melatonin was investigated. The size, zeta potential and melatonin loading of the lecithin/chitosan NPs were investigated as a function of lecithin type (Lipoid S45, S75 and S100) and chitosan content in the preparation. The NPs were characterised by mean diameter and zeta potential ranging between 121.6 and 347.5 nm, and 7.5 and 32.7 mV, respectively, and increasing with lecithin-negative charge and chitosan content in the preparation. Melatonin loadings were up to 7.1%. All NPs were characterised by prolonged release profiles with an initial burst (approximately 25%), followed by a slow release phase. Approximately 60-70% of melatonin was released in 4h. The permeability of melatonin was investigated using Caco-2 cells as an in vitro model of the epithelial barrier. Melatonin permeability from an NP suspension prepared with Lipoid S45 lecithin and a lecithin-to-chitosan weight ratio (L/C) of 20:1 (sample C2) was significantly improved compared to the permeability of melatonin from the solution (P<0.001) and from all other NPs investigated (P<0.05). The results obtained by the cell viability studies (MTT and LDH leakage assays) showed that C2 NP suspension did not induce plasma membrane damage or decrease cell viability and could be safely applied to Caco-2 cells in the concentration range tested (<400 microg/ml).

Inferring Viral Dynamics in Chronically HCV Infected Patients from the Spatial Distribution of Infected Hepatocytes

DOE PAGES

Graw, Frederik; Balagopal, Ashwin; Kandathil, Abraham J.; ...

2014-11-13

Chronic liver infection by hepatitis C virus (HCV) is a major public health concern. Despite partly successful treatment options, several aspects of intrahepatic HCV infection dynamics are still poorly understood, including the preferred mode of viral propagation, as well as the proportion of infected hepatocytes. Answers to these questions have important implications for the development of therapeutic interventions. In this study, we present methods to analyze the spatial distribution of infected hepatocytes obtained by single cell laser capture microdissection from liver biopsy samples of patients chronically infected with HCV. By characterizing the internal structure of clusters of infected cells, wemore » are able to evaluate hypotheses about intrahepatic infection dynamics. We found that individual clusters on biopsy samples range in size from 4-50 infected cells. In addition, the HCV RNA content in a cluster declines from the cell that presumably founded the cluster to cells at the maximal cluster extension. These observations support the idea that HCV infection in the liver is seeded randomly (e.g. from the blood) and then spreads locally. Assuming that the amount of intracellular HCV RNA is a proxy for how long a cell has been infected, we estimate based on models of intracellular HCV RNA replication and accumulation that cells in clusters have been infected on average for less than a week. Further, we do not find a relationship between the cluster size and the estimated cluster expansion time. Lastly, our method represents a novel approach to make inferences about infection dynamics in solid tissues from static spatial data.« less

Inferring Viral Dynamics in Chronically HCV Infected Patients from the Spatial Distribution of Infected Hepatocytes

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

Graw, Frederik; Balagopal, Ashwin; Kandathil, Abraham J.

Chronic liver infection by hepatitis C virus (HCV) is a major public health concern. Despite partly successful treatment options, several aspects of intrahepatic HCV infection dynamics are still poorly understood, including the preferred mode of viral propagation, as well as the proportion of infected hepatocytes. Answers to these questions have important implications for the development of therapeutic interventions. In this study, we present methods to analyze the spatial distribution of infected hepatocytes obtained by single cell laser capture microdissection from liver biopsy samples of patients chronically infected with HCV. By characterizing the internal structure of clusters of infected cells, wemore » are able to evaluate hypotheses about intrahepatic infection dynamics. We found that individual clusters on biopsy samples range in size from 4-50 infected cells. In addition, the HCV RNA content in a cluster declines from the cell that presumably founded the cluster to cells at the maximal cluster extension. These observations support the idea that HCV infection in the liver is seeded randomly (e.g. from the blood) and then spreads locally. Assuming that the amount of intracellular HCV RNA is a proxy for how long a cell has been infected, we estimate based on models of intracellular HCV RNA replication and accumulation that cells in clusters have been infected on average for less than a week. Further, we do not find a relationship between the cluster size and the estimated cluster expansion time. Lastly, our method represents a novel approach to make inferences about infection dynamics in solid tissues from static spatial data.« less

Effect of a dam on the optical properties of different-sized fractions of dissolved organic matter in a mid-subtropical drinking water source reservoir.

PubMed

Sun, Qiyuan; Jiang, Juan; Zheng, Yuyi; Wang, Feifeng; Wu, Chunshan; Xie, Rong-Rong

2017-11-15

The presence of a dam on a river is believed to have a key role in affecting changes in the components of the chromophoric dissolved organic matter (CDOM) in reservoirs. However, questions remain about the mechanisms that control these changes. In this study, we used tangential ultrafiltration, fluorescence spectrum and phytoplankton cell density detection to explore the impacts of a dam on the CDOM components in the Shanzai Reservoir, a source of drinking water. The results demonstrated each CDOM size fraction comprised two main components, namely C1 (protein-like substance) and C2 (humic-like substance). The C1 content had a higher value in areas with slow flow than in the normal river channel, while the C2 contents were generally stable in the flow direction. The topography of the reservoir site affected the structure of the CDOM components based on changes in the hydraulic conditions caused by the dam. The variations in the CDOM components, hydraulic parameters and fluorescence indices in the river flow direction indicated that the contribution of the phytoplankton to the CDOM content increased as the distance to the dam decreased, phytoplankton metabolism enhanced C1 content of the 1-10kDa molecular weights range fraction. Further, the contributions of different phytoplankton biomass to C1 proved that the dam changed the hydraulic conditions, had secondary effects on the metabolism of the phytoplankton, and resulted in changes in the structure of the CDOM components. Copyright © 2017 Elsevier B.V. All rights reserved.

Characteristics of fly ashes from full-scale coal-fired power plants and their relationship to mercury adsorption

USGS Publications Warehouse

Lu, Y.; Rostam-Abadi, M.; Chang, R.; Richardson, C.; Paradis, J.

2007-01-01

Nine fly ash samples were collected from the particulate collection devices (baghouse or electrostatic precipitator) of four full-scale pulverized coal (PC) utility boilers burning eastern bituminous coals (EB-PC ashes) and three cyclone utility boilers burning either Powder River Basin (PRB) coals or PRB blends,(PRB-CYC ashes). As-received fly ash samples were mechanically sieved to obtain six size fractions. Unburned carbon (UBC) content, mercury content, and Brunauer-Emmett-Teller (BET)-N2 surface areas of as-received fly ashes and their size fractions were measured. In addition, UBC particles were examined by scanning electron microscopy, high-resolution transmission microscopy, and thermogravimetry to obtain information on their surface morphology, structure, and oxidation reactivity. It was found that the UBC particles contained amorphous carbon, ribbon-shaped graphitic carbon, and highly ordered graphite structures. The mercury contents of the UBCs (Hg/UBC, in ppm) in raw ash samples were comparable to those of the UBC-enriched samples, indicating that mercury was mainly adsorbed on the UBC in fly ash. The UBC content decreased with a decreasing particle size range for all nine ashes. There was no correlation between the mercury and UBC contents of different size fractions of as-received ashes. The mercury content of the UBCs in each size fraction, however, generally increased with a decreasing particle size for the nine ashes. The mercury contents and surface areas of the UBCs in the PRB-CYC ashes were about 8 and 3 times higher than UBCs in the EB-PC ashes, respectively. It appeared that both the particle size and surface area of UBC could contribute to mercury capture. The particle size of the UBC in PRB-CYC ash and thus the external mass transfer was found to be the major factor impacting the mercury adsorption. Both the particle size and surface reactivity of the UBC in EB-PC ash, which generally had a lower carbon oxidation reactivity than the PRB-PC ashes, appeared to be important for the mercury adsorption. ?? 2007 American Chemical Society.

A test of bone mobilization relative to reproductive demand: skeletal quality is improved in cannibalistic females with large litters.

PubMed

Hood, Wendy R

2012-01-01

In species with repeated bouts of reproduction, a female's ability to retain sufficient tissue for self-maintenance is essential to her survival and capacity for future reproduction. Loss of bone mineral content results in bone fragility and the possibility of reduced survival, so females should guard against the overuse of their bone mineral during reproduction. Given these constraints, I predicted that bone mobilization would increase with litter size in mice but plateau before maximum litter size was reached. To test this idea, I manipulated the litter sizes of house mice on the day of parturition to 3, 8, 13, and 18 offspring. At weaning, I euthanized the females and calculated whole-body and bone mineral composition. The total mineral content of females' femurs dropped as litter size increased to the average litter size for this strain of mouse (13) but surprisingly, femoral mineral content was higher for females assigned the largest litter sizes (18). Seven of the nine females assigned 18 young cannibalized some of their offspring. For females assigned to these larger litters, femoral ash content was not correlated with number of young consumed, suggesting that mineral recycling had little effect on final bone mineral content. However, nursing effort (accounting for young lost to cannibalism) was correlated with maternal femoral ash at weaning. These finding suggest that the high bone mineral content of females assigned the largest litters was associated with a reduction in endogenous mineral allocated to the litter.

Measuring changes in the mass of single subcellular organelles using x-ray microscopy

NASA Astrophysics Data System (ADS)

Goncz, Kaarin K.; Moronne, Mario M.; Lin, W.; Rothman, Stephen S.

1993-01-01

Using quantitative scanning transmission x-ray microscopy, zymogen granules isolated from pancreatic acinar cells were observed suspended in aqueous medium at 50 nm resolution. From 3.64 nm x-ray absorption data, the protein content and rate of protein efflux from individual granules were determined. This was accomplished with a specially designed silicon nitride based wet-cell that allowed continuous perfusion and monitoring of individual granules in a variety of different aqueous environments. Granules suspended in 300 mM sucrose, 5 mM phosphate buffer (pH 6.0) were observed to continuously decrease in size and protein content over a period of several hours. Sudden lysis of the granules was not observed. From the flux data, the apparent protein permeability coefficients for individual granules were determined to range from 1 - 10 X 10-10 cm/sec with an average of 4.78 +/- 3.0 X 10-10 cm/sec. We believe this is the first quantitative population profile determined for a subcellular organelle developed from measurements of individual members of the population.

Phase Competition Induced Bio-Electrochemical Resistance and Bio-Compatibility Effect in Nanocrystalline Zr x -Cu100-x Thin Films.

PubMed

Badhirappan, Geetha Priyadarshini; Nallasivam, Vignesh; Varadarajan, Madhuri; Leobeemrao, Vasantha Priya; Bose, Sivakumar; Venugopal, Elakkiya; Rajendran, Selvakumar; Angleo, Peter Chrysologue

2018-07-01

Nano-crystalline Zrx-Cu100-x (x = 20-100 at.%) thin films with thickness ranging from 50 to 185 nm were deposited by magnetron co-sputtering with individual Zr and Cu targets. The as-sputtered thin films were characterized by Field Emission Scanning Electron Microscope (FE-SEM), Atomic Force Microscopy (AFM) and Glancing Incidence X-ray Diffraction (GIXRD) for structural and morphological properties. The crystallite size was found to decrease from 57 nm to 37 nm upon increasing the Zr content from 20 to 30 at.% with slight increase in the lattice strain from 0.17 to 0.33%. Further, increase in Zr content to 40 at.% leads to increase in the crystallite size to 57 nm due to stabilization of C10Zr7 phase along with the presence of nanocrystalline Cu-Zr phase. A bimodal distribution of grain size was observed from FE-SEM micrograph was attributed to the highest surface roughness in Zr30Cu70 thin films comprised of Cu10Zr7, Cu9Zr2, Cu-Zr intermetallic phases. In-vitro electrochemical behaviors of nano-crystalline Zrx-Cu100-x thin films in simulated body fluid (SBF) were investigated using potentiodynamic polarization studies. Electrochemical impedance spectroscopy (EIS) data fitting by equivalent electrical circuit fit model suggests that inner bulk layer contributes to high bio-corrosion resistance in Zrx-Cu100-x thin films with increase in Zr content. The results of cyto-compatibility assay suggested that Zr-Cu thin film did not introduce cytotoxicity to osteoblast cells, indicating its suitability as a bio-coating for minimally invasive medical devices.

Analysis of the effect of waste's particle size variations on biodrying method

NASA Astrophysics Data System (ADS)

Kristanto, Gabriel Andari; Zikrina, Masayu Nadiya

2017-11-01

The use of municipal solid waste as energy source can be a solution for Indonesia's increasing energy demand. However, its high moisture content limits the use of solid waste as energy. Biodrying is a method of lowering wastes' moisture content using biological process. This study investigated the effect of wastes' particle size variations on biodrying method. The experiment was performed on 3 lab-scale reactors with the same specifications. Organic wastes with the composition of 50% vegetable wastes and 50% garden wastes were used as substrates. The feedstock was manually shredded into 3 size variations, which were 10 - 40 mm, 50 - 80 mm, and 100 - 300 mm. The experiment lasted for 21 days. After 21 days, it was shown that the waste with the size of 100 - 300 mm has the lowest moisture content, which is 50.99%, and the volatile solids content is still 74.3% TS. This may be caused by the higher free air space of the reactor with the bigger sized substrate.

Structural Evolution of Q-Carbon and Nanodiamonds

NASA Astrophysics Data System (ADS)

Gupta, Siddharth; Bhaumik, Anagh; Sachan, Ritesh; Narayan, Jagdish

2018-04-01

This article provides insights pertaining to the first-order phase transformation involved in the growth of densely packed Q-carbon and nanodiamonds by nanosecond laser melting and quenching of diamond-like carbon (DLC) thin films. DLC films with different sp 3 content were melted rapidly in a controlled way in super-undercooled state and quenched, leading to formation of distinct nanostructures, i.e., nanodiamonds, Q-carbon, and Q-carbon nanocomposites. This analysis provides direct evidence of the dependence of the super-undercooling on the structural evolution of Q-carbon. Finite element heat flow calculations showed that the super-undercooling varies monotonically with the sp 3 content. The phenomenon of solid-liquid interfacial instability during directional solidification from the melt state is studied in detail. The resulting lateral segregation leads to formation of cellular filamentary Q-carbon nanostructures. The dependence of the cell size and wavelength at the onset of instability on the sp 3 content of DLC thin films was modeled based on perturbation theory.

Citrate gel synthesis of aluminum-doped lithium lanthanum titanate solid electrolyte for application in organic-type lithium-oxygen batteries

NASA Astrophysics Data System (ADS)

Le, Hang T. T.; Kalubarme, Ramchandra S.; Ngo, Duc Tung; Jang, Seong-Yong; Jung, Kyu-Nam; Shin, Kyoung-Hee; Park, Chan-Jin

2015-01-01

Aluminium doped lithium lanthanum titanate (A-LLTO) powders with various excess Li2O content are synthesized using a simple citrate gel method. The obtained A-LLTO powders show an agglomerated form, composed of nano-sized particles of 20-50 nm. The morphology and conductivity of the A-LLTO ceramics are largely affected by the content of excess Li2O. The highest total ionic conductivity of 3.17 × 10-4 S cm-1 is achieved for the A-LLTO sample containing 20% excess Li2O, exhibiting a vacancy content of 6%, and a total activation energy of 0.358 eV. The A-LLTO can act as a membrane to protect lithium metal from oxygen and other contaminants diffused through the oxygen electrode part. The Li-O2 cell employing the A-LLTO solid electrolyte shows a good cycle life of longer than 100 discharge-charge cycles, under the constant capacity mode of 300 mAh g-1.

Enhanced MEA Performance for PEMFCs under Low Relative Humidity and Low Oxygen Content Conditions via Catalyst Functionalization

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

Xin, Le; Yang, Fan; Xie, Jian

2017-01-01

This work demonstrates that functionalizing annealed-Pt/Ketjen black EC300j (a-Pt/KB) and dealloyed-PtNi/Ketjen black EC300j (d-PtNi/KB) catalysts using p-phenyl sulfonic acid can effectively enhance performance in the membrane electrode assemblies (MEAs) of proton exchange membrane fuel cells (PEMFCs). The functionalization increased the size of both Pt and PtNi catalyst particles and resulted in the further leaching of Ni from the PtNi catalyst while promoting the formation of nanoporous PtNi nanoparticles. The size of the SO3H-Pt/KB and SO3H-PtNi/KB carbon-based aggregates decreased dramatically, leading to the formation of catalyst layers with narrower pore size distributions.MEA tests highlighted the benefits of the surface functionalization, inmore » which the cells with SO3H-Pt/KB and SO3H-PtNi/KB cathode catalysts showed superior high current density performance under reduced RH conditions, in comparison with cells containing annealed Pt/KB (a-Pt/KB) and de-alloyed PtNi/KB (d-PtNi/KB) catalysts. The performance improvement was particularly evident when using reactant gases with low relative humidity, indicating that the hydrophilic functional groups on the carbon improved the water retention in the cathode catalyst layer. These results show a new avenue for enhancing catalyst performance for the next generation of catalytic materials for PEMFCs.« less

Albumin/gentamicin microspheres produced by supercritical assisted atomization: optimization of size, drug loading and release.

PubMed

Della Porta, G; Adami, R; Del Gaudio, P; Prota, L; Aquino, R; Reverchon, E

2010-11-01

In this work, the supercritical assisted atomization (SAA) is proposed, for the first time, not only as a micronization technology but also as a thermal coagulation process for the production of bovine serum albumin (BSA) microspheres charged with Gentamicin sulfate (GS). Particularly, different water solutions of BSA/GS were processed by SAA to produce protein microspheres with different size and antibiotic content. SAA precipitation temperature was selected in the range 100-130 °C to generate protein coagulation and to recover micronized BSA in form of hydrophobic aggregates; GS loading was varied between 10% and 50% (w/w) with an encapsulation efficiency which often reached 100%. In all cases, spherical and noncoalescing particles were successfully produced with a mean particle size of 2 µm and with a standard deviation of about ±1 µm. The microspheres also showed a good stability and constant water content after 60 days of storage. The release profiles of the entrapped drug were monitored using Franz cells to evaluate the possible application of the produced microspheres in wound dressing formulations. Particularly, the microspheres with a BSA/GS ratio of 4:1 after the first burst effect (of 40% of GS loaded) were able to release the GS continuously over 10 days. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association

Particle seeding enhances interconnectivity in polymeric scaffolds foamed using supercritical CO(2).

PubMed

Collins, Niki J; Bridson, Rachel H; Leeke, Gary A; Grover, Liam M

2010-03-01

Foaming using supercritical CO(2) is a well-known process for the production of polymeric scaffolds for tissue engineering. However, this method typically leads to scaffolds with low pore interconnectivity, resulting in insufficient mass transport and a heterogeneous distribution of cells. In this study, microparticulate silica was added to the polymer during processing and the effects of this particulate seeding on the interconnectivity of the pore structure and pore size distribution were investigated. Scaffolds comprising polylactide and a range of silica contents (0-50 wt.%) were produced by foaming with supercritical CO(2). Scaffold structure, pore size distributions and interconnectivity were assessed using X-ray computed microtomography. Interconnectivity was also determined through physical measurements. It was found that incorporation of increasing quantities of silica particles increased the interconnectivity of the scaffold pore structure. The pore size distribution was also reduced through the addition of silica, while total porosity was found to be largely independent of silica content. Physical measurements and those derived from X-ray computed microtomography were comparable. The conclusion drawn was that the architecture of foamed polymeric scaffolds can be advantageously manipulated through the incorporation of silica microparticles. The findings of this study further establish supercritical fluid foaming as an important tool in scaffold production and show how a previous limitation can be overcome. Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Metabolism of native and naturally occurring multiple modified low density lipoprotein in smooth muscle cells of human aortic intima.

PubMed

Tertov, V V; Orekhov, A N

1997-01-01

The subfraction of low density lipoprotein (LDL) with low sialic acid content that caused accumulation of cholesterol esters in human aortic smooth muscle cells has been found in the blood of coronary atherosclerosis patients. It was demonstrated that this subfraction consists of LDL with small size, high electronegative charge, reduced lipid content, altered tertiary structure of apolipoprotein B, etc. LDL of this subfraction is naturally occurring multiple-modified LDL (nomLDL). In this study we compared the binding, uptake and proteolytic degradation of native LDL and nomLDL by smooth muscle cells cultured from human grossly normal intima, fatty streaks, and atherosclerotic plaques. Uptake of nomLDL by normal and atherosclerotic cells was 3.5- and 6-fold, respectively, higher than uptake of native LDL. Increased uptake of nomLDL was due to increased binding of this LDL by intimal smooth muscle cells. The enhanced binding is explained by the interaction of nomLDL with cellular receptors other than LDL-receptor. Modified LDL interacted with the scavenger receptor, asialoglycoprotein receptor, and also with cell surface proteoglycans. Rates of degradation of nomLDL were 1.5- and 5-fold lower than degradation of native LDL by normal and atherosclerotic cells, respectively. A low rate of nomLDL degradation was also demonstrated in homogenates of intimal cells. Activities of lysosomal proteinases of atherosclerotic cells were decreased compared with normal cells. Pepstatin A, a cathepsin D inhibitor, completely inhibited lipoprotein degradation, while serine, thiol, or metallo-proteinase inhibitors had partial effect. This fact reveals that cathepsin D is involved in initial stages of apoB degradation by intimal smooth muscle cells. Obtained data show that increased uptake and decreased lysosomal degradation of nomLDL may be the main cause of LDL accumulation in human aortic smooth muscle cells, leading to foam cell formation.

Representation of ideal figure size in Ebony magazine: a content analysis.

PubMed

Thompson-Brenner, Heather; Boisseau, Christina L; St Paul, Michelle S

2011-09-01

Studies examining trends over time in mainstream magazines observe decreases in women's figure size, and increases in figure exposure and amount of diet/exercise content. Little is known, however, regarding the content of African American magazines. Utilizing methods from classic studies, this investigation examined content in Ebony, a magazine with wide African American readership, from 1969 to 2008. We included the full content of N=462 issues, with a total of N=539 cover images of women, of which N=208 were full-body shots. Analyses indicated a curvilinear relationship between time and figure exposure, with a recent trend toward more full-body shots, similar to mainstream magazines. Contrary to previous studies, however, the majority of figures across time were average size, and a curvilinear relationship between time and diet/exercise content showed peak content in the early 1990s. Results are considered in context of research indicating African American women show less body dissatisfaction than other racial/ethnic groups. Copyright © 2011 Elsevier Ltd. All rights reserved.

Engineering Potato Starch with a Higher Phosphate Content

PubMed Central

Xu, Xuan; Huang, Xing-Feng; Visser, Richard G. F.

2017-01-01

Phosphate esters are responsible for valuable and unique functionalities of starch for industrial applications. Also in the cell phosphate esters play a role in starch metabolism, which so far has not been well characterized in storage starch. Laforin, a human enzyme composed of a carbohydrate-binding module and a dual-specificity phosphatase domain, is involved in the dephosphorylation of glycogen. To modify phosphate content and better understand starch (de)phosphorylation in storage starch, laforin was engineered and introduced into potato (cultivar Kardal). Interestingly, expression of an (engineered) laforin in potato resulted in significantly higher phosphate content of starch, and this result was confirmed in amylose-free potato genetic background (amf). Modified starches exhibited altered granule morphology and size compared to the control. About 20–30% of the transgenic lines of each series showed red-staining granules upon incubation with iodine, and contained higher phosphate content than the blue-stained starch granules. Moreover, low amylose content and altered gelatinization properties were observed in these red-stained starches. Principle component and correlation analysis disclosed a complex correlation between starch composition and starch physico-chemical properties. Ultimately, the expression level of endogenous genes involved in starch metabolism was analysed, revealing a compensatory response to the decrease of phosphate content in potato starch. This study provides a new perspective for engineering starch phosphate content in planta by making use of the compensatory mechanism in the plant itself. PMID:28056069

Indirect rapid prototyping of sol-gel hybrid glass scaffolds for bone regeneration - Effects of organic crosslinker valence, content and molecular weight on mechanical properties.

PubMed

Hendrikx, Stephan; Kascholke, Christian; Flath, Tobias; Schumann, Dirk; Gressenbuch, Mathias; Schulze, F Peter; Hacker, Michael C; Schulz-Siegmund, Michaela

2016-04-15

We present a series of organic/inorganic hybrid sol-gel derived glasses, made from a tetraethoxysilane-derived silica sol (100% SiO2) and oligovalent organic crosslinkers functionalized with 3-isocyanatopropyltriethoxysilane. The material was susceptible to heat sterilization. The hybrids were processed into pore-interconnected scaffolds by an indirect rapid prototyping method, described here for the first time for sol-gel glass materials. A large panel of polyethylene oxide-derived 2- to 4-armed crosslinkers of molecular weights ranging between 170 and 8000Da were incorporated and their effect on scaffold mechanical properties was investigated. By multiple linear regression, 'organic content' and the 'content of ethylene oxide units in the hybrid' were identified as the main factors that determined compressive strength and modulus, respectively. In general, 3- and 4-armed crosslinkers performed better than linear molecules. Compression tests and cell culture experiments with osteoblast-like SaOS-2 cells showed that macroporous scaffolds can be produced with compressive strengths of up to 33±2MPa and with a pore structure that allows cells to grow deep into the scaffolds and form mineral deposits. Compressive moduli between 27±7MPa and 568±98MPa were obtained depending on the hybrid composition and problems associated with the inherent brittleness of sol-gel glass materials could be overcome. SaOS-2 cells showed cytocompatibility on hybrid glass scaffolds and mineral accumulation started as early as day 7. On day 14, we also found mineral accumulation on control hybrid glass scaffolds without cells, indicating a positive effect of the hybrid glass on mineral accumulation. We produced a hybrid sol-gel glass material with significantly improved mechanical properties towards an application in bone regeneration and processed the material into macroporous scaffolds of controlled architecture by indirect rapid prototyping. We were able to produce macroporous materials of relevant porosity and pore size with compressive moduli, covering the range reported for cancellous bone while an even higher compressive strength was maintained. By multiple linear regression, we identified crosslinker parameters, namely organic content and the content of ethylene oxide units in the hybrids that predominantly determined the mechanics of the hybrid materials. The scaffolds proved to be cytocompatible and induced mineralization in SaOS-2 cells. This provides new insight on the critical parameters for the design of the organic components of covalent hybrid sol-gel glasses. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

To the nucleolar bodies (nucleoli) in cells of the lymphocytic lineage in patients suffering from B - chronic lymphocytic leukemia.

PubMed

Smetana, K; Karban, J; Trneny, M

2010-01-01

The present study was undertaken to provide more information on nucleoli in lymphocytes of B - chronic lymphocytic leukemia. The computer assisted nucleolar and cytoplasmic RNA image densitometry, reflecting the nucleolar and cytoplasmic RNA concentration at the single cell level, demonstrated a remarkable stability during the differentiation and maturation of B- lymphocytes. In contrast, as it was expected, the nucleolar diameter during the lymphocytic development markedly decreased. Thus the nucleolar RNA content of leukemic B-lymphocytes was apparently related to the nucleolar size. In both immature and mature lymphocytes, the cytostatic treatment increased the incidence of micronucleoli, which represent the "inactive" type of nucleoli. However, the decreased values of the nucleolar diameter were statistically significant only in mature lymphocytes of treated patients. On the other hand, despite such observation, it must be mentioned that "large active" and "ring shaped resting" nucleoli were still present in immature and mature lymphocytes after the cytostatic therapy and such cells might represent a potential pool of proliferating cells. As it is generally accepted "large active nucleoli" with multiple fibrillar centers are known to be characteristic for proliferating cells. "Ring shaped resting nucleoli" are present in sleeping cells, which may be stimulated to return to the cell cycle and to proliferate again. In addition, the nucleolar RNA distribution also indicated that Gumprecht ghosts mostly originated from mature lymphocytes. Increased ratio of the nucleolar to cytoplasmic RNA density in Gumprecht ghosts or apoptotic cells and apoptotic bodies of the lymphocytic origin was related to the decreased cytoplasmic RNA concentration. The increased nucleolar size together with the markedly decreased cytoplasmic RNA concentration characteristic for Gumprecht ghosts just reflected the spreading of lymphocytes during smear preparations. In apoptotic cells or bodies of the lymphocytic origin, the "frozen" nucleolar RNA concentration accompanied by a reduced RNA concentration in the cytoplasm exhibited a remarkable similarity to the apoptotic process induced in vitro by the cytostatic treatment. B-chronic lymphocytic leukemia; lymphocytes; nucleolar classes; size; nucleolar RNA image density -concentration.

NanoTopoChip: High-throughput nanotopographical cell instruction.

PubMed

Hulshof, Frits F B; Zhao, Yiping; Vasilevich, Aliaksei; Beijer, Nick R M; de Boer, Meint; Papenburg, Bernke J; van Blitterswijk, Clemens; Stamatialis, Dimitrios; de Boer, Jan

2017-10-15

Surface topography is able to influence cell phenotype in numerous ways and offers opportunities to manipulate cells and tissues. In this work, we develop the Nano-TopoChip and study the cell instructive effects of nanoscale topographies. A combination of deep UV projection lithography and conventional lithography was used to fabricate a library of more than 1200 different defined nanotopographies. To illustrate the cell instructive effects of nanotopography, actin-RFP labeled U2OS osteosarcoma cells were cultured and imaged on the Nano-TopoChip. Automated image analysis shows that of many cell morphological parameters, cell spreading, cell orientation and actin morphology are mostly affected by the nanotopographies. Additionally, by using modeling, the changes of cell morphological parameters could by predicted by several feature shape parameters such as lateral size and spacing. This work overcomes the technological challenges of fabricating high quality defined nanoscale features on unprecedented large surface areas of a material relevant for tissue culture such as PS and the screening system is able to infer nanotopography - cell morphological parameter relationships. Our screening platform provides opportunities to identify and study the effect of nanotopography with beneficial properties for the culture of various cell types. The nanotopography of biomaterial surfaces can be modified to influence adhering cells with the aim to improve the performance of medical implants and tissue culture substrates. However, the necessary knowledge of the underlying mechanisms remains incomplete. One reason for this is the limited availability of high-resolution nanotopographies on relevant biomaterials, suitable to conduct systematic biological studies. The present study shows the fabrication of a library of nano-sized surface topographies with high fidelity. The potential of this library, called the 'NanoTopoChip' is shown in a proof of principle HTS study which demonstrates how cells are affected by nanotopographies. The large dataset, acquired by quantitative high-content imaging, allowed us to use predictive modeling to describe how feature dimensions affect cell morphology. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

An assessment of the effects of cell size on AGNPS modeling of watershed runoff

USGS Publications Warehouse

Wu, S.-S.; Usery, E.L.; Finn, M.P.; Bosch, D.D.

2008-01-01

This study investigates the changes in simulated watershed runoff from the Agricultural NonPoint Source (AGNPS) pollution model as a function of model input cell size resolution for eight different cell sizes (30 m, 60 m, 120 m, 210 m, 240 m, 480 m, 960 m, and 1920 m) for the Little River Watershed (Georgia, USA). Overland cell runoff (area-weighted cell runoff), total runoff volume, clustering statistics, and hot spot patterns were examined for the different cell sizes and trends identified. Total runoff volumes decreased with increasing cell size. Using data sets of 210-m cell size or smaller in conjunction with a representative watershed boundary allows one to model the runoff volumes within 0.2 percent accuracy. The runoff clustering statistics decrease with increasing cell size; a cell size of 960 m or smaller is necessary to indicate significant high-runoff clustering. Runoff hot spot areas have a decreasing trend with increasing cell size; a cell size of 240 m or smaller is required to detect important hot spots. Conclusions regarding cell size effects on runoff estimation cannot be applied to local watershed areas due to the inconsistent changes of runoff volume with cell size; but, optimal cells sizes for clustering and hot spot analyses are applicable to local watershed areas due to the consistent trends.

Study on extrusion process of SiC ceramic matrix

NASA Astrophysics Data System (ADS)

Dai, Xiao-Yuan; Shen, Fan; Ji, Jia-You; Wang, Shu-Ling; Xu, Man

2017-11-01

In this thesis, the extrusion process of SiC ceramic matrix has been systematically studied.The effect of different cellulose content on the flexural strength and pore size distribution of SiC matrix was discussed.Reselts show that with the increase of cellulose content, the flexural strength decreased.The pore size distribution in the sample was 1um-4um, and the 1um-2um concentration was more concentrated. It is found that the cellulose content has little effect on the pore size distribution.When the cellulose content is 7%, the flexural strength of the sample is 40.9Mpa. At this time, the mechanical properties of the sample are the strongest.

Phytotoxicity, accumulation and transport of silver nanoparticles by Arabidopsis thaliana.

PubMed

Geisler-Lee, Jane; Wang, Qiang; Yao, Ying; Zhang, Wen; Geisler, Matt; Li, Kungang; Huang, Ying; Chen, Yongsheng; Kolmakov, Andrei; Ma, Xingmao

2013-05-01

The widespread availability of nano-enabled products in the global market may lead to the release of a substantial amount of engineered nanoparticles in the environment, which frequently display drastically different physiochemical properties than their bulk counterparts. The purpose of the study was to evaluate the impact of citrate-stabilised silver nanoparticles (AgNPs) on the plant Arabidopsis thaliana at three levels, physiological phytotoxicity, cellular accumulation and subcellular transport of AgNPs. The monodisperse AgNPs of three different sizes (20, 40 and 80 nm) aggregated into much larger sizes after mixing with quarter-strength Hoagland solution and became polydisperse. Immersion in AgNP suspension inhibited seedling root elongation and demonstrated a linear dose-response relationship within the tested concentration range. The phytotoxic effect of AgNPs could not be fully explained by the released silver ions. Plants exposed to AgNP suspensions bioaccumulated higher silver content than plants exposed to AgNO3 solutions (Ag(+) representative), indicating AgNP uptake by plants. AgNP toxicity was size and concentration dependent. AgNPs accumulated progressively in this sequence: border cells, root cap, columella and columella initials. AgNPs were apoplastically transported in the cell wall and found aggregated at plasmodesmata. In all the three levels studied, AgNP impacts differed from equivalent dosages of AgNO3.

Molecular dissection of nutrient exchange at the insect-microbial interface.

PubMed

Douglas, Angela E

2014-10-01

Genome research is transforming our understanding of nutrient exchange between insects and intracellular bacteria. A key characteristic of these bacteria is their small genome size and gene content. Their fastidious and inflexible nutritional requirements are met by multiple metabolites from the insect host cell. Although the bacteria have generally retained genes coding the synthesis of nutrients required by the insect, some apparently critical genes have been lost, and compensated for by shared metabolic pathways with the insect host or supplementary bacteria with complementary metabolic capabilities. Copyright © 2014 Elsevier Inc. All rights reserved.

Silk fibroin/kappa-carrageenan composite scaffolds with enhanced biomimetic mineralization for bone regeneration applications.

PubMed

Nourmohammadi, Jhamak; Roshanfar, Fahimeh; Farokhi, Mehdi; Haghbin Nazarpak, Masoumeh

2017-07-01

The combination of protein-polysaccharide in scaffolding together with the ability to induce bone-like apatite formation has become a promising approach to mimic extracellular matrix composition. In the present study, we developed and characterized new bioactive composite scaffolds from kappa-carrageenan/silk fibroin for bone regeneration applications. Three dimensional (3D) scaffolds were fabricated by adding various amounts of carrageenan to a silk fibroin solution, followed by freeze-drying. Various characterization techniques were applied to analyze such items as the structure, morphology, compressive strength, and bone-like apatite mineralization of the composites, which were then compared to those of pure fibroin scaffolds. The results demonstrated the formation of a highly porous structure with interconnected pores. The mean pore size and porosity both increased by increasing carrageenan content. Moreover, the addition of carrageenan to silk fibroin led to the formation of a bone-like apatite layer throughout the scaffolds after 7days of soaking them in simulated body fluid. Osteoblast-like cell (MG 63) culture experiments indicated that all scaffolds are biocompatible. The cells attached well to the surfaces of all scaffolds and tended to join their adjacent cells. However, higher carrageenan content led to better cellular proliferation and higher Alkaline phosphatase expression. Copyright © 2017 Elsevier B.V. All rights reserved.

[Stability of whole cell biocatalyst for biodiesel production from renewable oils].

PubMed

Sun, Ting; Du, Wei; Liu, Dehua; Li, Wei; Zeng, Jing; Dai, Lingmei

2009-09-01

Lipase-mediated biodiesel production becomes increasingly important because of mild reaction conditions, pollution free during the process and easy product separation. Compared with traditional immobilized lipase, whole cell biocatalyst is promising for biodiesel production because it is easy to prepare and has higher enzyme activity recovery. Rhizopus oryzae IFO4697 can be used as the catalyst for biodiesel production. To further study the stability of the whole cell biocatalyst is extremely important for its further application on large scale. This paper focuses on the stability study of Rhizopus oryzae IFO4697 when used for the methanolysis of renewable oils for biodiesel production. The results showed that water content was important for achieving high catalytic activity and good stability of the biocatalyst. The optimum water content was found to be 5%-15%. Both particle size and desiccation methods showed no obvious effect on the stability of the biocatalyst. With GA cross-linking pretreatment, the stability of the biocatalyst could be improved significantly. When Rhizopus oryzae IFO4697 repeatedly used for next batch reaction, direct vacuum filtration was found to be a good way for the maintenance of good stability of the biocatalyst. Under the optimum reaction conditions, the methyl ester yield could keep over 80% during 20 repeated reaction batches.

The effect of between-breast differences on human milk macronutrients content.

PubMed

Pines, N; Mandel, D; Mimouni, F B; Moran Lev, H; Mangel, L; Lubetzky, R

2016-07-01

Little is known about the effect of maternal handedness and preferential side of breastfeeding upon macronutrients concentration in human milk (HM). We aimed to compare macronutrients content of HM from both breasts, taking into account the self-reported preferential feeding ('dominant') breast, breast size and handedness (right versus left). We tested the null hypothesis that macronutrients content of HM is not affected by breast dominancy, breast size or maternal handedness. Fifty-seven lactating mothers were recruited. HM macronutrients were measured after mid manual expression using infrared transmission spectroscopy. Out of the 57 mothers recruited, 12 were excluded from the analyses because they brought in insufficient samples. Among the 22 who reported a size difference, 16 (73%) had a larger left breast (P<0.001). Approximately a third of women reported no breastfeeding side dominance, a third reported a right dominance and another third reported a left dominance. Breastfeeding side dominance was unaffected by either handedness or breasts size. When size asymmetry was reported (n=22) the dominant side was also the larger breast in 16 (73%) women, the smaller breast in 2 (9%) women, whereas 4 (18%) additional women with asymmetry had no preferential breastfeeding side. There were no statistically significant differences in macronutrients between the right and the left breasts. In multiple stepwise backward regression analysis, fat, carbohydrate, protein and energy contents were unaffected by maternal handedness, breast side dominance or breast size asymmetry. Macronutrients content of mid expression HM is unaffected by maternal handedness, breast size or breast side dominance.

Liquid water content and droplet size calibration of the NASA Lewis Icing Research Tunnel

NASA Technical Reports Server (NTRS)

Ide, Robert F.

1989-01-01

The icing research tunnel at the NASA Lewis Research Center underwent a major rehabilitation in 1986 to 1987, necessitating recalibration of the icing cloud. The methods used in the recalibration, including the procedure used to establish a uniform icing cloud and the use of a standard icing blade technique for measurement of liquid water content are described. PMS Forward Scattering Spectrometer and Optical Array probes were used for measurement of droplet size. Examples of droplet size distributions are shown for several median volumetric diameters. Finally, the liquid water content/droplet size operating envelopes of the icing tunnel are shown for a range of airspeeds and are compared to the FAA icing certification criteria.

Resolving protein interactions and organization downstream the T cell antigen receptor using single-molecule localization microscopy: a review

NASA Astrophysics Data System (ADS)

Sherman, Eilon

2016-06-01

Signal transduction is mediated by heterogeneous and dynamic protein complexes. Such complexes play a critical role in diverse cell functions, with the important example of T cell activation. Biochemical studies of signalling complexes and their imaging by diffraction limited microscopy have resulted in an intricate network of interactions downstream the T cell antigen receptor (TCR). However, in spite of their crucial roles in T cell activation, much remains to be learned about these signalling complexes, including their heterogeneous contents and size distribution, their complex arrangements in the PM, and the molecular requirements for their formation. Here, we review how recent advancements in single molecule localization microscopy have helped to shed new light on the organization of signalling complexes in single molecule detail in intact T cells. From these studies emerges a picture where cells extensively employ hierarchical and dynamic patterns of nano-scale organization to control the local concentration of interacting molecular species. These patterns are suggested to play a critical role in cell decision making. The combination of SMLM with more traditional techniques is expected to continue and critically contribute to our understanding of multimolecular protein complexes and their significance to cell function.

Energy Content Estimation by Collegians for Portion Standardized Foods Frequently Consumed in Korea

PubMed Central

Kim, Jin; Lee, Hee Jung; Lee, Hyun Jung; Lee, Sun Ha; Yun, Jee-Young; Choi, Mi-Kyeong

2014-01-01

The purpose of this study is to estimate Korean collegians' knowledge of energy content in the standard portion size of foods frequently consumed in Korea and to investigate the differences in knowledge between gender groups. A total of 600 collegians participated in this study. Participants' knowledge was assessed based on their estimation on the energy content of 30 selected food items with their actual-size photo images. Standard portion size of food was based on 2010 Korean Dietary Reference Intakes, and the percentage of participants who accurately estimated (that is, within 20% of the true value) the energy content of the standard portion size was calculated for each food item. The food for which the most participants provided the accurate estimation was ramyun (instant noodles) (67.7%), followed by cooked rice (57.8%). The proportion of students who overestimated the energy content was highest for vegetables (68.8%) and beverages (68.1%). The proportion of students who underestimated the energy content was highest for grains and starches (42.0%) and fruits (37.1%). Female students were more likely to check energy content of foods that they consumed than male students. From these results, it was concluded that the knowledge on food energy content was poor among collegians, with some gender difference. Therefore, in the future, nutrition education programs should give greater attention to improving knowledge on calorie content and to helping them apply this knowledge in order to develop effective dietary plans. PMID:24527417

Energy content estimation by collegians for portion standardized foods frequently consumed in Korea.

PubMed

Kim, Jin; Lee, Hee Jung; Lee, Hyun Jung; Lee, Sun Ha; Yun, Jee-Young; Choi, Mi-Kyeong; Kim, Mi-Hyun

2014-01-01

The purpose of this study is to estimate Korean collegians' knowledge of energy content in the standard portion size of foods frequently consumed in Korea and to investigate the differences in knowledge between gender groups. A total of 600 collegians participated in this study. Participants' knowledge was assessed based on their estimation on the energy content of 30 selected food items with their actual-size photo images. Standard portion size of food was based on 2010 Korean Dietary Reference Intakes, and the percentage of participants who accurately estimated (that is, within 20% of the true value) the energy content of the standard portion size was calculated for each food item. The food for which the most participants provided the accurate estimation was ramyun (instant noodles) (67.7%), followed by cooked rice (57.8%). The proportion of students who overestimated the energy content was highest for vegetables (68.8%) and beverages (68.1%). The proportion of students who underestimated the energy content was highest for grains and starches (42.0%) and fruits (37.1%). Female students were more likely to check energy content of foods that they consumed than male students. From these results, it was concluded that the knowledge on food energy content was poor among collegians, with some gender difference. Therefore, in the future, nutrition education programs should give greater attention to improving knowledge on calorie content and to helping them apply this knowledge in order to develop effective dietary plans.

Seed Structure Characteristics to Form Ultrahigh Oil Content in Rapeseed

PubMed Central

Zhang, Liang; Deng, Lin-Bin; Wang, Xin-Fa; Liu, Gui-Hua; Hao, Wan-Jun; Wang, Han-Zhong

2013-01-01

Background Rapeseed (Brassica napus L.) is an important oil crop in the world, and increasing its oil content is a major breeding goal. The studies on seed structure and characteristics of different oil content rapeseed could help us to understand the biological mechanism of lipid accumulation, and be helpful for rapeseed breeding. Methodology/Principal Findings Here we report on the seed ultrastructure of an ultrahigh oil content rapeseed line YN171, whose oil content is 64.8%, and compared with other high and low oil content rapeseed lines. The results indicated that the cytoplasms of cotyledon, radicle, and aleuronic cells were completely filled with oil and protein bodies, and YN171 had a high oil body organelle to cell area ratio for all cell types. In the cotyledon cells, oil body organelles comprised 81% of the total cell area in YN171, but only 53 to 58% in three high oil content lines and 33 to 38% in three low oil content lines. The high oil body organelle to cotyledon cell area ratio and the cotyledon ratio in seed were the main reasons for the ultrahigh oil content of YN171. The correlation analysis indicated that oil content is significantly negatively correlated with protein content, but is not correlated with fatty acid composition. Conclusions/Significance Our results indicate that the oil content of YN171 could be enhanced by increasing the oil body organelle to cell ratio for some cell types. The oil body organelle to seed ratio significantly highly positively correlates with oil content, and could be used to predict seed oil content. Based on the structural analysis of different oil content rapeseed lines, we estimate the maximum of rapeseed oil content could reach 75%. Our results will help us to screen and identify high oil content lines in rapeseed breeding. PMID:23637973

Effect of cell-size on the energy absorption features of closed-cell aluminium foams

NASA Astrophysics Data System (ADS)

Nammi, S. K.; Edwards, G.; Shirvani, H.

2016-11-01

The effect of cell-size on the compressive response and energy absorption features of closed-cell aluminium (Al) foam were investigated by finite element method. Micromechanical models were constructed with a repeating unit-cell (RUC) which was sectioned from tetrakaidecahedra structure. Using this RUC, three Al foam models with different cell-sizes (large, medium and small) and all of same density, were built. These three different cell-size pieces of foam occupy the same volume and their domains contained 8, 27 and 64 RUCs respectively. However, the smaller cell-size foam has larger surface area to volume ratio compared to other two. Mechanical behaviour was modelled under uniaxial loading. All three aggregates (3D arrays of RUCs) of different cell-sizes showed an elastic region at the initial stage, then followed by a plateau, and finally, a densification region. The smaller cell size foam exhibited a higher peak-stress and a greater densification strain comparing other two cell-sizes investigated. It was demonstrated that energy absorption capabilities of smaller cell-size foams was higher compared to the larger cell-sizes examined.

Early- and later-phases satellite cell responses and myonuclear content with resistance training in young men.

PubMed

Damas, Felipe; Libardi, Cleiton A; Ugrinowitsch, Carlos; Vechin, Felipe C; Lixandrão, Manoel E; Snijders, Tim; Nederveen, Joshua P; Bacurau, Aline V; Brum, Patricia; Tricoli, Valmor; Roschel, Hamilton; Parise, Gianni; Phillips, Stuart M

2018-01-01

Satellite cells (SC) are associated with skeletal muscle remodelling after muscle damage and/or extensive hypertrophy resulting from resistance training (RT). We recently reported that early increases in muscle protein synthesis (MPS) during RT appear to be directed toward muscle damage repair, but MPS contributes to hypertrophy with progressive muscle damage attenuation. However, modulations in acute-chronic SC content with RT during the initial (1st-wk: high damage), early (3rd-wk: attenuated damage), and later (10th-wk: no damage) stages is not well characterized. Ten young men (27 ± 1 y, 23.6 ± 1.0 kg·m-2) underwent 10-wks of RT and muscle biopsies (vastus-lateralis) were taken before (Pre) and post (48h) the 1st (T1), 5th (T2) and final (T3) RT sessions to evaluate fibre type specific SC content, cross-sectional area (fCSA) and myonuclear number by immunohistochemistry. We observed RT-induced hypertrophy after 10-wks of RT (fCSA increased ~16% in type II, P < 0.04; ~8% in type I [ns]). SC content increased 48h post-exercise at T1 (~69% in type I [P = 0.014]; ~42% in type II [ns]), and this increase was sustained throughout RT (pre T2: ~65%, ~92%; pre T3: ~30% [ns], ~87%, for the increase in type I and II, respectively, vs. pre T1 [P < 0.05]). Increased SC content was not coupled with changes in myonuclear number. SC have a more pronounced role in muscle repair during the initial phase of RT than muscle hypertrophy resulted from 10-wks RT in young men. Chronic elevated SC pool size with RT is important providing proper environment for future stresses or larger fCSA increases.

Inverse size scaling of the nucleolus by a concentration-dependent phase transition.

PubMed

Weber, Stephanie C; Brangwynne, Clifford P

2015-03-02

Just as organ size typically increases with body size, the size of intracellular structures changes as cells grow and divide. Indeed, many organelles, such as the nucleus [1, 2], mitochondria [3], mitotic spindle [4, 5], and centrosome [6], exhibit size scaling, a phenomenon in which organelle size depends linearly on cell size. However, the mechanisms of organelle size scaling remain unclear. Here, we show that the size of the nucleolus, a membraneless organelle important for cell-size homeostasis [7], is coupled to cell size by an intracellular phase transition. We find that nucleolar size directly scales with cell size in early C. elegans embryos. Surprisingly, however, when embryo size is altered, we observe inverse scaling: nucleolar size increases in small cells and decreases in large cells. We demonstrate that this seemingly contradictory result arises from maternal loading of a fixed number rather than a fixed concentration of nucleolar components, which condense into nucleoli only above a threshold concentration. Our results suggest that the physics of phase transitions can dictate whether an organelle assembles, and, if so, its size, providing a mechanistic link between organelle assembly and cell size. Since the nucleolus is known to play a key role in cell growth, this biophysical readout of cell size could provide a novel feedback mechanism for growth control. Copyright © 2015 Elsevier Ltd. All rights reserved.

Detection of early changes in lung-cell cytology by flow-systems analysis techniques. Progress report, January 1--June 30, 1976

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

Steinkamp, J. A.; Hansen, K. M.; Wilson, J. S.

1976-08-01

This report summarizes results of preliminary experiments to develop cytological and biochemical indicators for estimating damage to respiratory epithelium exposed to toxic agents associated with the by-products of nonnuclear energy production using advanced flow-systems cell-analysis technologies. Since initiation of the program one year ago, progress has been made in obtaining adequate numbers of exfoliated lung cells from the Syrian hamster for flow analysis; cytological techniques developed on human exfoliated gynecological samples have been adapted to hamster lung epithelium for obtaining single-cell suspensions; and lung-cell samples have been initially characterized based on DNA content, total protein, nuclear and cytoplasmic size, andmore » multiangle light-scatter measurements. Preliminary results from measurements of the above parameters which recently became available are described in this report. As the flow-systems technology is adapted further to analysis of exfoliated lung cells, measurements of changes in physical and biochemical cellular properties as a function of exposure to toxic agents will be performed.« less

Application of nonflammable electrolyte with room temperature ionic liquids (RTILs) for lithium-ion cells

NASA Astrophysics Data System (ADS)

Nakagawa, Hiroe; Fujino, Yukiko; Kozono, Suguru; Katayama, Yoshihiro; Nukuda, Toshiyuki; Sakaebe, Hikari; Matsumoto, Hajime; Tatsumi, Kuniaki

A mixture of flammable organic solvent and nonflammable room temperature ionic liquid (RTIL) has been investigated as a new concept electrolyte to improve the safety of lithium-ion cells. This study focused on the use of N-methyl- N-propylpiperidinium bis (trifluoromethanesulfonyl) imide (PP13-TFSI) as the RTIL for the flame-retardant additive. It was found that a carbon negative electrode, both graphite and hard carbon, could be used with the mixed electrolyte. A 383562-size lithium-ion trial cell made with the mixed electrolyte showed good discharge capacity, which was equivalent to a cell with conventional organic electrolyte up to a discharge current rate of complete discharge in 1 h. Moreover, the mixed electrolyte was observed to be nonflammable at ionic liquid contents of 40 mass% or more. Thus the mixed electrolyte was found to realize both nonflammability and the good discharge performance of lithium-ion cells with carbon negative electrodes. These results indicate that RTILs have potential as a flame-retardant additive for the organic electrolytes used in lithium-ion cells.

The emerging roles and therapeutic potential of exosomes in epithelial ovarian cancer.

PubMed

Li, Xiaoduan; Wang, Xipeng

2017-05-15

Ovarian cancer (OC) is one of the three types of malignant tumors in the female reproductive system, and epithelial ovarian cancer (EOC) is its most typical form. Due to the asymptomatic nature of the early stages and resistance to chemotherapy, EOC has both a poor prognosis and a high fatality rate. Current treatments for OC are very limited, and the 5-years survival rate is approximately 30%. Exosomes, which are microvesicles ranging from approximately 30-100 nm in size that are secreted by living cells, can be produced from different cell types and detected in various body fluids. Cancer cells can secrete more exosomes than healthy cells, and more importantly, the content of cancer cell-derived exosomes is distinct. The exosomes shedding from tumor cells are considered to be involved in tumor progression and metastasis. As such, exosomes are expected to be potential tools for tumor diagnosis and treatment. In this review, we briefly present the emerging roles of exosomes in OC and summarize related articles about their roles as diagnostic or prognostic biomarkers and in the treatment and drug resistance of OC.

Concerted evolution of body mass and cell size: similar patterns among species of birds (Galliformes) and mammals (Rodentia)

PubMed Central

Dragosz-Kluska, Dominika; Pis, Tomasz; Pawlik, Katarzyna; Kapustka, Filip; Kilarski, Wincenty M.; Kozłowski, Jan

2018-01-01

ABSTRACT Cell size plays a role in body size evolution and environmental adaptations. Addressing these roles, we studied body mass and cell size in Galliformes birds and Rodentia mammals, and collected published data on their genome sizes. In birds, we measured erythrocyte nuclei and basal metabolic rates (BMRs). In birds and mammals, larger species consistently evolved larger cells for five cell types (erythrocytes, enterocytes, chondrocytes, skin epithelial cells, and kidney proximal tubule cells) and evolved smaller hepatocytes. We found no evidence that cell size differences originated through genome size changes. We conclude that the organism-wide coordination of cell size changes might be an evolutionarily conservative characteristic, and the convergent evolutionary body size and cell size changes in Galliformes and Rodentia suggest the adaptive significance of cell size. Recent theory predicts that species evolving larger cells waste less energy on tissue maintenance but have reduced capacities to deliver oxygen to mitochondria and metabolize resources. Indeed, birds with larger size of the abovementioned cell types and smaller hepatocytes have evolved lower mass-specific BMRs. We propose that the inconsistent pattern in hepatocytes derives from the efficient delivery system to hepatocytes, combined with their intense involvement in supracellular function and anabolic activity. PMID:29540429

A self-sustained, complete and miniaturized methanol fuel processor for proton exchange membrane fuel cell

NASA Astrophysics Data System (ADS)

Yang, Mei; Jiao, Fengjun; Li, Shulian; Li, Hengqiang; Chen, Guangwen

2015-08-01

A self-sustained, complete and miniaturized methanol fuel processor has been developed based on modular integration and microreactor technology. The fuel processor is comprised of one methanol oxidative reformer, one methanol combustor and one two-stage CO preferential oxidation unit. Microchannel heat exchanger is employed to recover heat from hot stream, miniaturize system size and thus achieve high energy utilization efficiency. By optimized thermal management and proper operation parameter control, the fuel processor can start up in 10 min at room temperature without external heating. A self-sustained state is achieved with H2 production rate of 0.99 Nm3 h-1 and extremely low CO content below 25 ppm. This amount of H2 is sufficient to supply a 1 kWe proton exchange membrane fuel cell. The corresponding thermal efficiency of whole processor is higher than 86%. The size and weight of the assembled reactors integrated with microchannel heat exchangers are 1.4 L and 5.3 kg, respectively, demonstrating a very compact construction of the fuel processor.

Preliminary study of semi-refined carrageenan (SRC) as secondary gelling agent in natural rubber (NR) latex foam

NASA Astrophysics Data System (ADS)

Norhazariah, S.; Azura, A. R.; Azahari, B.; Sivakumar, R.

2017-12-01

Semi-refined carrageenan (SRC) product is considerably cheaper and easier to produce as a natural polysaccharide, which was utilized in food and other product application. However, the application in latex is limited. The aim of this work is to evaluate the SRC produced from low industrial grade seaweed (LIGS) in the latex foam application. The FTIR spectra showed the SRC produced as kappa type carrageenan with lower sulfur content compared to native LIGS. NR latex foam is produced by using the Dunlop method with some modifications. The effect of SRC loading as a secondary gelling agent in NR latex foam is investigated. The density and morphology of the NR latex foam with the addition of the SRC are analyzed. NR latex foam density increased with SRC loading and peaked at 1.8 phr SRC. The addition of SRC has induced the bigger cell size compared to the cell size of the control NR latex foam, as shown in the optical micrograph. It can be concluded that SRC LIGS could be acted as secondary gelling agent in NR latex foam.

Effects of size and moisture of rhizome on initial invasiveness ability of giant reed.

PubMed

Santín-Montanyá, M I; Jimenéz, J; Vilán, X M; Ocaña, L

2014-01-01

Studies were conducted under controlled conditions to determine growth and reproductive capabilities of Arundo donax L. (giant reed), a riparian invasive perennial plant that has spread widely. Greenhouse experiments were conducted to determine the influence of rhizome size and moisture content in the early invasiveness ability of giant reed. We tested different sizes of rhizomes: rhizome size of 1 cm, 3 cm, 5 cm and shredded rhizome. (fragments < 1 cm). These rhizomes were observed at 7, 14, 21, 28 and 35 days after planting (DAP). To test the effect of moisture content we used fresh rhizome fragments; rhizomes with moderate dehydration (50%); rhizomes with high dehydration (over 70%) with 48 hours of rehydration and rhizomes with high dehydration (70-90%). The rhizomes monitored for moisture content and biomass increase were between 3 and 5 cm, and were observed 60 DAP. The initial size of rhizomes affected the level of sprouting. Rhizomes with low moisture content (due to dehydration) showed high increase in biomass compared with the rhizomes that had not been treated or had been dehydrated and then rehydrated. Our results indicated that size of rhizomes is related to regrowth and low moisture (dehydration) content can be overcome by this species. This could be linked to high rates of colonization and early establishment ability of this species even after mechanical treatment of rhizomes, in riparian environments.

Selection for Oil Content During Soybean Domestication Revealed by X-Ray Tomography of Ancient Beans

NASA Astrophysics Data System (ADS)

Zong, Yunbing; Yao, Shengkun; Crawford, Gary W.; Fang, Hui; Lang, Jianfeng; Fan, Jiadong; Sun, Zhibin; Liu, Yang; Zhang, Jianhua; Duan, Xiulan; Zhou, Guangzhao; Xiao, Tiqiao; Luan, Fengshi; Wang, Qing; Chen, Xuexiang; Jiang, Huaidong

2017-02-01

When and under what circumstances domestication related traits evolved in soybean (Glycine max) is not well understood. Seed size has been a focus of archaeological attention because increased soybean seed weight/size is a trait that distinguishes most modern soybeans from their ancestors; however, archaeological seed size analysis has had limited success. Modern domesticated soybean has a significantly higher oil content than its wild counterpart so oil content is potentially a source of new insight into soybean domestication. We investigated soybean oil content using X-ray computed tomography (CT; specifically, synchrotron radiation X-ray CT or SRX-CT) of charred, archaeological soybean seeds. CT identified holes in the specimens that are associated with oil content. A high oil content facilitates the development of small holes, whereas a high protein content results in larger holes. The volume of small holes increased slowly from 7,500 to 4,000 cal B.P. We infer that human selection for higher oil content began as early as 7,500 cal B.P. and that high oil content cultivars were well established by 4,000 cal B.P.

Selection for Oil Content During Soybean Domestication Revealed by X-Ray Tomography of Ancient Beans

PubMed Central

Zong, Yunbing; Yao, Shengkun; Crawford, Gary W.; Fang, Hui; Lang, Jianfeng; Fan, Jiadong; Sun, Zhibin; Liu, Yang; Zhang, Jianhua; Duan, Xiulan; Zhou, Guangzhao; Xiao, Tiqiao; Luan, Fengshi; Wang, Qing; Chen, Xuexiang; Jiang, Huaidong

2017-01-01

When and under what circumstances domestication related traits evolved in soybean (Glycine max) is not well understood. Seed size has been a focus of archaeological attention because increased soybean seed weight/size is a trait that distinguishes most modern soybeans from their ancestors; however, archaeological seed size analysis has had limited success. Modern domesticated soybean has a significantly higher oil content than its wild counterpart so oil content is potentially a source of new insight into soybean domestication. We investigated soybean oil content using X-ray computed tomography (CT; specifically, synchrotron radiation X-ray CT or SRX-CT) of charred, archaeological soybean seeds. CT identified holes in the specimens that are associated with oil content. A high oil content facilitates the development of small holes, whereas a high protein content results in larger holes. The volume of small holes increased slowly from 7,500 to 4,000 cal B.P. We infer that human selection for higher oil content began as early as 7,500 cal B.P. and that high oil content cultivars were well established by 4,000 cal B.P. PMID:28240321

Selection for Oil Content During Soybean Domestication Revealed by X-Ray Tomography of Ancient Beans.

PubMed

Zong, Yunbing; Yao, Shengkun; Crawford, Gary W; Fang, Hui; Lang, Jianfeng; Fan, Jiadong; Sun, Zhibin; Liu, Yang; Zhang, Jianhua; Duan, Xiulan; Zhou, Guangzhao; Xiao, Tiqiao; Luan, Fengshi; Wang, Qing; Chen, Xuexiang; Jiang, Huaidong

2017-02-27

When and under what circumstances domestication related traits evolved in soybean (Glycine max) is not well understood. Seed size has been a focus of archaeological attention because increased soybean seed weight/size is a trait that distinguishes most modern soybeans from their ancestors; however, archaeological seed size analysis has had limited success. Modern domesticated soybean has a significantly higher oil content than its wild counterpart so oil content is potentially a source of new insight into soybean domestication. We investigated soybean oil content using X-ray computed tomography (CT; specifically, synchrotron radiation X-ray CT or SRX-CT) of charred, archaeological soybean seeds. CT identified holes in the specimens that are associated with oil content. A high oil content facilitates the development of small holes, whereas a high protein content results in larger holes. The volume of small holes increased slowly from 7,500 to 4,000 cal B.P. We infer that human selection for higher oil content began as early as 7,500 cal B.P. and that high oil content cultivars were well established by 4,000 cal B.P.

A THERMODYNAMIC ANALYSIS OF MITOTIC SPINDLE EQUILIBRIUM AT ACTIVE METAPHASE

PubMed Central

Stephens, R. E.

1973-01-01

The mitotic apparatus of first-division metaphase eggs of the sea urchin Strongylocentrotus drobachiensis was observed by means of polarization microscopy under controlled temperature conditions. Eggs were fertilized and grown at two temperature extremes in order to produce two different sizes of available spindle pool. Slow division time allowed successive samples of such cells to be observed at the same point in metaphase but at different equilibrium temperatures, yielding curves of metaphase equilibrium birefringence vs. observational temperature. Using the plateau value of birefringence at higher temperatures as a measure of total available spindle pool and the observed birefringence at lower temperatures as a measure of polymerized material at equilibrium, the spindle protein association was evaluated according to the method of Inoué. Both pool conditions produced linear van't Hoff functions. Analysis of these functions yielded enthalpy and entropy changes of +55–65 kcal/mol and +197–233 entropy units (eu), respectively. These values for active mitotic metaphase are quite comparable to those obtained by Inoué and co-workers for arrested meiotic metaphase cells. When other equilibrium treatments were considered, the best fit to the experimental data was still that of Inoué, a treatment which theoretically involves first-order polymerization and dissociation kinetics. Treatment of metaphase cells with D2O by direct immersion drove the equilibrium to completion regardless of temperature, attaining or exceeding a birefringence value equal to the cell's characteristic pool size; perfusion with D2O appeared to erase the original temperature-determined pool size differences for the two growth conditions, attaining a maximum value characteristic of the larger pool condition. These data confirm Inoué's earlier contention that D2O treatment can modify the available spindle pool. PMID:4734864

Limited genomic heterogeneity of circulating melanoma cells in advanced stage patients

NASA Astrophysics Data System (ADS)

Ruiz, Carmen; Li, Julia; Luttgen, Madelyn S.; Kolatkar, Anand; Kendall, Jude T.; Flores, Edna; Topp, Zheng; Samlowski, Wolfram E.; McClay, Edward; Bethel, Kelly; Ferrone, Soldano; Hicks, James; Kuhn, Peter

2015-02-01

Purpose. Circulating melanoma cells (CMCs) constitute a potentially important representation of time-resolved tumor biology in patients. To date, genomic characterization of CMCs has been limited due to the lack of a robust methodology capable of identifying them in a format suitable for downstream characterization. Here, we have developed a methodology to detect intact CMCs that enables phenotypic, morphometric and genomic analysis at the single cell level. Experimental design. Blood samples from 40 metastatic melanoma patients and 10 normal blood donors were prospectively collected. A panel of 7 chondroitin sulfate proteoglycan 4 (CSPG4)-specific monoclonal antibodies (mAbs) was used to immunocytochemically label CMCs. Detection was performed by automated digital fluorescence microscopy and multi-parametric computational analysis. Individual CMCs were captured by micromanipulation for whole genome amplification and copy number variation (CNV) analysis. Results. Based on CSPG4 expression and nuclear size, 1-250 CMCs were detected in 22 (55%) of 40 metastatic melanoma patients (0.5-371.5 CMCs ml-1). Morphometric analysis revealed that CMCs have a broad spectrum of morphologies and sizes but exhibit a relatively homogeneous nuclear size that was on average 1.5-fold larger than that of surrounding PBMCs. CNV analysis of single CMCs identified deletions of CDKN2A and PTEN, and amplification(s) of TERT, BRAF, KRAS and MDM2. Furthermore, novel chromosomal amplifications in chr12, 17 and 19 were also found. Conclusions. Our findings show that CSPG4 expressing CMCs can be found in the majority of advanced melanoma patients. High content analysis of this cell population may contribute to the design of effective personalized therapies in patients with melanoma.

Essentially All Excess Fibroblast Cholesterol Moves from Plasma Membranes to Intracellular Compartments

PubMed Central

Lange, Yvonne; Ye, Jin; Steck, Theodore L.

2014-01-01

It has been shown that modestly increasing plasma membrane cholesterol beyond its physiological set point greatly increases the endoplasmic reticulum and mitochondrial pools, thereby eliciting manifold feedback responses that return cell cholesterol to its resting state. The question arises whether this homeostatic mechanism reflects the targeting of cell surface cholesterol to specific intracellular sites or its general equilibration among the organelles. We now show that human fibroblast cholesterol can be increased as much as two-fold from 2-hydroxypropyl-β-cyclodextrin without changing the size of the cell surface pool. Rather, essentially all of the added cholesterol disperses rapidly among cytoplasmic membranes, increasing their overall cholesterol content by as much as five-fold. We conclude that the level of plasma membrane cholesterol is normally at capacity and that even small increments above this physiological set point redistribute essentially entirely to intracellular membranes, perhaps down their chemical activity gradients. PMID:25014655

Analyzing the dynamics of cell cycle processes from fixed samples through ergodic principles

PubMed Central

Wheeler, Richard John

2015-01-01

Tools to analyze cyclical cellular processes, particularly the cell cycle, are of broad value for cell biology. Cell cycle synchronization and live-cell time-lapse observation are widely used to analyze these processes but are not available for many systems. Simple mathematical methods built on the ergodic principle are a well-established, widely applicable, and powerful alternative analysis approach, although they are less widely used. These methods extract data about the dynamics of a cyclical process from a single time-point “snapshot” of a population of cells progressing through the cycle asynchronously. Here, I demonstrate application of these simple mathematical methods to analysis of basic cyclical processes—cycles including a division event, cell populations undergoing unicellular aging, and cell cycles with multiple fission (schizogony)—as well as recent advances that allow detailed mapping of the cell cycle from continuously changing properties of the cell such as size and DNA content. This includes examples using existing data from mammalian, yeast, and unicellular eukaryotic parasite cell biology. Through the ongoing advances in high-throughput cell analysis by light microscopy, electron microscopy, and flow cytometry, these mathematical methods are becoming ever more important and are a powerful complementary method to traditional synchronization and time-lapse cell cycle analysis methods. PMID:26543196

Restoring the quantity and quality of elderly human mesenchymal stem cells for autologous cell-based therapies.

PubMed

Block, Travis J; Marinkovic, Milos; Tran, Olivia N; Gonzalez, Aaron O; Marshall, Amanda; Dean, David D; Chen, Xiao-Dong

2017-10-27

Degenerative diseases are a major public health concern for the aging population and mesenchymal stem cells (MSCs) have great potential for treating many of these diseases. However, the quantity and quality of MSCs declines with aging, limiting the potential efficacy of autologous MSCs for treating the elderly population. Human bone marrow (BM)-derived MSCs from young and elderly donors were obtained and characterized using standard cell surface marker criteria (CD73, CD90, CD105) as recommended by the International Society for Cellular Therapy (ISCT). The elderly MSC population was isolated into four subpopulations based on size and stage-specific embryonic antigen-4 (SSEA-4) expression using fluorescence-activated cell sorting (FACS), and subpopulations were compared to the unfractionated young and elderly MSCs using assays that evaluate MSC proliferation, quality, morphology, intracellular reactive oxygen species, β-galactosidase expression, and adenosine triphosphate (ATP) content. The ISCT-recommended cell surface markers failed to detect any differences between young and elderly MSCs. Here, we report that elderly MSCs were larger in size and displayed substantially higher concentrations of intracellular reactive oxygen species and β-galactosidase expression and lower amounts of ATP and SSEA-4 expression. Based on these findings, cell size and SSEA-4 expression were used to separate the elderly MSCs into four subpopulations by FACS. The original populations (young and elderly MSCs), as well as the four subpopulations, were then characterized before and after culture on tissue culture plastic and BM-derived extracellular matrix (BM-ECM). The small SSEA-4-positive subpopulation representing ~ 8% of the original elderly MSC population exhibited a "youthful" phenotype that was similar to that of young MSCs. The biological activity of this elderly subpopulation was inhibited by senescence-associated factors produced by the unfractionated parent population. After these "youthful" cells were isolated and expanded (three passages) on a "young microenvironment" (i.e., BM-ECM produced by BM cells from young donors), the number of cells increased ≈ 17,000-fold to 3 × 10 9 cells and retained their "youthful" phenotype. These results suggest that it is feasible to obtain large numbers of high-quality autologous MSCs from the elderly population and establish personal stem cell banks that will allow serial infusions of "rejuvenated" MSCs for treating age-related diseases.

Effects of double ligation of Stensen's duct on the rabbit parotid gland.

PubMed

Maria, O M; Maria, S M; Redman, R S; Maria, A M; Saad El-Din, T A; Soussa, E F; Tran, S D

2014-04-01

Salivary gland duct ligation is an alternative to gland excision for treating sialorrhea or reducing salivary gland size prior to tumor excision. Duct ligation also is used as an approach to study salivary gland aging, regeneration, radiotherapy, sialolithiasis and sialadenitis. Reports conflict about the contribution of each salivary cell population to gland size reduction after ductal ligation. Certain cell populations, especially acini, reportedly undergo atrophy, apoptosis and proliferation during reduction of gland size. Acini also have been reported to de-differentiate into ducts. These contradictory results have been attributed to different animal or salivary gland models, or to methods of ligation. We report here a bilateral double ligature technique for rabbit parotid glands with histologic observations at 1, 7, 14, 30, 60 days after ligation. A large battery of special stains and immunohistochemical procedures was employed to define the cell populations. Four stages with overlapping features were observed that led to progressive shutdown of gland activities: 1) marked atrophy of the acinar cells occurred by 14 days, 2) response to and removal of the secretory material trapped in the acinar and ductal lumens mainly between 30 and 60 days, 3) reduction in the number of parenchymal (mostly acinar) cells by apoptosis that occurred mainly between 14-30 days, and 4) maintenance of steady-state at 60 days with a low rate of fluid, protein, and glycoprotein secretion, which greatly decreased the number of leukocytes engaged in the removal of the luminal contents. The main post- ligation characteristics were dilation of ductal and acinar lumens, massive transient infiltration of mostly heterophils (rabbit polymorphonuclear leukocytes), acinar atrophy, and apoptosis of both acinar and ductal cells. Proliferation was uncommon except in the larger ducts. By 30 days, the distribution of myoepithelial cells had spread from exclusively investing the intercalated ducts pre-ligation to surrounding a majority of the residual duct-like structures, many of which clearly were atrophic acini. Thus, both atrophy and apoptosis made major contributions to the post-ligation reduction in gland size. Structures also occurred with both ductal and acinar markers that suggested acini differentiating into ducts. Overall, the reaction to duct ligation proceeded at a considerably slower pace in the rabbit parotid glands than has been reported for the salivary glands of the rat.

Complementary role of parathormone washout test to 99mTc-MIBI parathyroid scintigraphy and histopathologic analysis of cell types in parathyroid adenomas.

PubMed

Ince, Semra; Emer, Ozdes; Deveci, Salih; Okuyucu, Kursat; Alagoz, Engin; San, Huseyin; Ayan, Aslı; Karacalioglu, Ozgur; Haymana, Cem; Gunalp, Bengul; Arslan, Nuri

2018-05-02

Parathyroid scintigraphy (PS) can be negative or equivocal (N/E) in a considerable number of cases with highly suspicious clinical findings and biochemical results for parathyroid adenoma (PA). The aims of this study were to investigate the complementary role of parathormone washout test (PWT) to PS in patients with primary hyperparathyroidism (PHPT) and evaluate histopathologic aspects of PAs in comparison with PS results. Thirty-eight patients with PHPT referred for PS were included in the study. Seventeen patients had both scintigraphic and ultrasonographic findings concordant with PA (Group A). Twenty-one patients having N/E PS, but suspected lesions for PA on ultrasonography (US) formed Group B. PWT was performed for all patients and they underwent the surgical intervention. An adenoma was removed in all patients and the histopathologic cell characteristics were established. The tumor size on US was larger in those patients whose adenomas were seen on the PS (P<.001). The percentages of chief (or principal), oxyphilic and clear cells in PAs were not statistically different between the groups. Serum parathormone level and PWT were not statistically significant between Group A and Group B (P=.095 and P=.04, respectively). Although there is not a definitive threshold value, the sensitivity of PS increases with lesion size. While chief cell and oxyphilic cell content of PAs tend to deplete in N/E PS, clear cell rate increases substantially. Combining PS with both US and PWT increases the sensitivity of detection and localization of PAs. Copyright © 2018. Publicado por Elsevier España, S.L.U.

Sterol synthesis and cell size distribution under oscillatory growth conditions in Saccharomyces cerevisiae scale-down cultivations.

PubMed

Marbà-Ardébol, Anna-Maria; Bockisch, Anika; Neubauer, Peter; Junne, Stefan

2018-02-01

Physiological responses of yeast to oscillatory environments as they appear in the liquid phase in large-scale bioreactors have been the subject of past studies. So far, however, the impact on the sterol content and intracellular regulation remains to be investigated. Since oxygen is a cofactor in several reaction steps within sterol metabolism, changes in oxygen availability, as occurs in production-scale aerated bioreactors, might have an influence on the regulation and incorporation of free sterols into the cell lipid layer. Therefore, sterol and fatty acid synthesis in two- and three-compartment scale-down Saccharomyces cerevisiae cultivation were studied and compared with typical values obtained in homogeneous lab-scale cultivations. While cells were exposed to oscillating substrate and oxygen availability in the scale-down cultivations, growth was reduced and accumulation of carboxylic acids was increased. Sterol synthesis was elevated to ergosterol at the same time. The higher fluxes led to increased concentrations of esterified sterols. The cells thus seem to utilize the increased availability of precursors to fill their sterol reservoirs; however, this seems to be limited in the three-compartment reactor cultivation due to a prolonged exposure to oxygen limitation. Besides, a larger heterogeneity within the single-cell size distribution was observed under oscillatory growth conditions with three-dimensional holographic microscopy. Hence the impact of gradients is also observable at the morphological level. The consideration of such a single-cell-based analysis provides useful information about the homogeneity of responses among the population. Copyright © 2017 John Wiley & Sons, Ltd.

Cytokinin Regulates the Activity of Reproductive Meristems, Flower Organ Size, Ovule Formation, and Thus Seed Yield in Arabidopsis thaliana[C][W][OA

PubMed Central

Bartrina, Isabel; Otto, Elisabeth; Strnad, Miroslav; Werner, Tomáš; Schmülling, Thomas

2011-01-01

The size and activity of the shoot apical meristem is regulated by transcription factors and low molecular mass signals, including the plant hormone cytokinin. The cytokinin status of the meristem depends on different factors, including metabolic degradation of the hormone, which is catalyzed by cytokinin oxidase/dehydrogenase (CKX) enzymes. Here, we show that CKX3 and CKX5 regulate the activity of the reproductive meristems of Arabidopsis thaliana. CKX3 is expressed in the central WUSCHEL (WUS) domain, while CKX5 shows a broader meristematic expression. ckx3 ckx5 double mutants form larger inflorescence and floral meristems. An increased size of the WUS domain and enhanced primordia formation indicate a dual function for cytokinin in defining the stem cell niche and delaying cellular differentiation. Consistent with this, mutation of a negative regulator gene of cytokinin signaling, ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN 6, which is expressed at the meristem flanks, caused a further delay of differentiation. Terminal cellular differentiation was also retarded in ckx3 ckx5 flowers, which formed more cells and became larger, corroborating the role of cytokinin in regulating flower organ size. Furthermore, higher activity of the ckx3 ckx5 placenta tissue established supernumerary ovules leading to an increased seed set per silique. Together, the results underpin the important role of cytokinin in reproductive development. The increased cytokinin content caused an ~55% increase in seed yield, highlighting the relevance of sink strength as a yield factor. PMID:21224426

The Effect of Screen Size on Mobile Phone User Comprehension of Health Information and Application Structure: An Experimental Approach.

PubMed

Al Ghamdi, Ebtisam; Yunus, Faisal; Da'ar, Omar; El-Metwally, Ashraf; Khalifa, Mohamed; Aldossari, Bakheet; Househ, Mowafa

2016-01-01

This research analyzes the impact of mobile phone screen size on user comprehension of health information and application structure. Applying experimental approach, we asked randomly selected users to read content and conduct tasks on a commonly used diabetes mobile application using three different mobile phone screen sizes. We timed and tracked a number of parameters, including correctness, effectiveness of completing tasks, content ease of reading, clarity of information organization, and comprehension. The impact of screen size on user comprehension/retention, clarity of information organization, and reading time were mixed. It is assumed on first glance that mobile screen size would affect all qualities of information reading and comprehension, including clarity of displayed information organization, reading time and user comprehension/retention of displayed information, but actually the screen size, in this experimental research, did not have significant impact on user comprehension/retention of the content or on understanding the application structure. However, it did have significant impact on clarity of information organization and reading time. Participants with larger screen size took shorter time reading the content with a significant difference in the ease of reading. While there was no significant difference in the comprehension of information or the application structures, there were a higher task completion rate and a lower number of errors with the bigger screen size. Screen size does not directly affect user comprehension of health information. However, it does affect clarity of information organization, reading time and user's ability to recall information.

Maintenance of a bone collagen phenotype by osteoblast-like cells in 3D periodic porous titanium (Ti-6Al-4 V) structures fabricated by selective electron beam melting

PubMed Central

Hrabe, Nikolas W.; Heinl, Peter; Bordia, Rajendra K.; Körner, Carolin; Fernandes, Russell J.

2013-01-01

Regular 3D periodic porous Ti-6Al-4 V structures were fabricated by the selective electron beam melting method (EBM) over a range of relative densities (0.17–0.40) and pore sizes (500–1500 μm). Structures were seeded with human osteoblast-like cells (SAOS-2) and cultured for four weeks. Cells multiplied within these structures and extracellular matrix collagen content increased. Type I and type V collagens typically synthesized by osteoblasts were deposited in the newly formed matrix with time in culture. High magnification scanning electron microscopy revealed cells attached to surfaces on the interior of the structures with an increasingly fibrous matrix. The in-vitro results demonstrate that the novel EBM-processed porous structures, designed to address the effect of stress-shielding, are conducive to osteoblast attachment, proliferation and deposition of a collagenous matrix characteristic of bone. PMID:23869614

Regulation of EGFR signal transduction by analogue-to-digital conversion in endosomes

PubMed Central

Villaseñor, Roberto; Nonaka, Hidenori; Del Conte-Zerial, Perla; Kalaidzidis, Yannis; Zerial, Marino

2015-01-01

An outstanding question is how receptor tyrosine kinases (RTKs) determine different cell-fate decisions despite sharing the same signalling cascades. Here, we uncovered an unexpected mechanism of RTK trafficking in this process. By quantitative high-resolution FRET microscopy, we found that phosphorylated epidermal growth factor receptor (p-EGFR) is not randomly distributed but packaged at constant mean amounts in endosomes. Cells respond to higher EGF concentrations by increasing the number of endosomes but keeping the mean p-EGFR content per endosome almost constant. By mathematical modelling, we found that this mechanism confers both robustness and regulation to signalling output. Different growth factors caused specific changes in endosome number and size in various cell systems and changing the distribution of p-EGFR between endosomes was sufficient to reprogram cell-fate decision upon EGF stimulation. We propose that the packaging of p-RTKs in endosomes is a general mechanism to ensure the fidelity and specificity of the signalling response. DOI: http://dx.doi.org/10.7554/eLife.06156.001 PMID:25650738

Cellular Biotechnology Operations Support Systems-Fluid Dynamics Investigation (CBOSS-FDI)

NASA Technical Reports Server (NTRS)

2003-01-01

Aboard the International Space Station (ISS), the Tissue Culture Module (TCM) is the stationary bioreactor vessel in which cell cultures grow. However, for the Cellular Biotechnology Operations Support Systems-Fluid Dynamics Investigation (CBOSS-FDI), color polystyrene beads are used to measure the effectiveness of various mixing procedures. Uniform mixing is a crucial component of CBOSS experiments involving the immune response of human lymphoid cell suspensions. In this picture, the beads are trapped in the injection port shortly after injection. Swirls of beads indicate, event to the naked eye, the contents of the TCM are not fully mixed. The beads are similar in size and density to human lymphoid cells. The goal is to develop procedures that are both convenient for the flight crew and are optimal in providing uniform and reproducible mixing of all components, including cells. The average bead density in a well mixed TCM will be uniform, with no bubbles, and it will be measured using the absorption of light

A hormone map of human immune cells showing the presence of adrenocorticotropic hormone, triiodothyronine and endorphin in immunophenotyped white blood cells

PubMed Central

Pállinger, Éva; Csaba, György

2008-01-01

The amounts of adrenocorticotropic hormone (ACTH), endorphin and triiodothyronine (T3) in twenty-six blood samples from men and women who were healthy or had non-haematological diseases were determined by flow cytometry. Lymphocytes were immunophenotyped using monoclonal antibodies against cell surface antigens, and monocytes and granulocytes were separated by their size and granularity (using forward-scatter versus side-scatter dot plots). Each hormone was found in each cell type. The hormone content of lymphocytes was balanced, but the concentration of ACTH was significantly lower in activated T cells, that of endorphin was significantly lower in natural killer (NK) cells, and that of T3 was lower in both cell types compared with values for all lymphocytes. Monocytes and granulocytes contained very significantly more hormones than lymphocytes or monocytes. The concentration of endorphin was an order of magnitude higher in granulocytes than in monocytes or lymphocytes, reflecting the pain-relieving role of granulocytes during inflammation. Compared with monocytes, in granulocytes there was a higher concentration of ACTH and a lower concentration of T3, which suggests selective hormone production by these cells. PMID:18005034

Biomarkers of Cell Senescence Assessed by Imaging Cytometry

PubMed Central

Zhao, Hong; Darzynkiewicz, Zbigniew

2012-01-01

The characteristic features of senescent cells such as their “flattened” appearance, enlarged nuclei and low saturation density at the plateau phase of cell growth, can be conveniently measured by image-assisted d cytometry such as provided by the laser scanning cytometry (LSC). The “flattening” of senescent cells is reflected by the decline in local density of staining (intensity of maximal pixel) of DNA-associated fluorescence [4,6-diamidino-2- phenylindole (DAPI)] paralleled by an increase in nuclear size (area). Thus, the ratio of the maximal pixel of DAPI fluorescence per nucleus to the nuclear area provides a very sensitive morphometric biomarker of “depth” of senescence, which progressively declines during induction of senescence. Also recorded is cellular DNA content revealing cell cycle phase, as well as the saturation cell density at plateau phase of growth, which is dramatically decreased in cultures of senescent cells. Concurrent immunocytochemical analysis of expression of p21WAF1, p16INK4a or p27KIP1 cyclin kinase inhibitor provides additional markers of senescence. These biomarker indices can be expressed in quantitative terms (“senescence indices”) as a fraction of the same markers of the exponentially growing cells in control cultures. PMID:23296652

Size uniformity of animal cells is actively maintained by a p38 MAPK-dependent regulation of G1-length.

PubMed

Liu, Shixuan; Ginzberg, Miriam Bracha; Patel, Nish; Hild, Marc; Leung, Bosco; Li, Zhengda; Chen, Yen-Chi; Chang, Nancy; Wang, Yuan; Tan, Ceryl; Diena, Shulamit; Trimble, William; Wasserman, Larry; Jenkins, Jeremy L; Kirschner, Marc W; Kafri, Ran

2018-03-29

Animal cells within a tissue typically display a striking regularity in their size. To date, the molecular mechanisms that control this uniformity are still unknown. We have previously shown that size uniformity in animal cells is promoted, in part, by size-dependent regulation of G1 length. To identify the molecular mechanisms underlying this process, we performed a large-scale small molecule screen and found that the p38 MAPK pathway is involved in coordinating cell size and cell cycle progression. Small cells display higher p38 activity and spend more time in G1 than larger cells. Inhibition of p38 MAPK leads to loss of the compensatory G1 length extension in small cells, resulting in faster proliferation, smaller cell size and increased size heterogeneity. We propose a model wherein the p38 pathway responds to changes in cell size and regulates G1 exit accordingly, to increase cell size uniformity. © 2017, Liu et al.

Structural, magnetic and impedance spectroscopic analysis of LaFeO3 nano-particles

NASA Astrophysics Data System (ADS)

Rao, T. Lakshmana; Pradhan, M. K.; Dash, S.

2018-04-01

Physical properties are known to be drastically varied with crystallite size and in a multifunctional material this size reduction is seem to be interesting. One such material is chosen as LaFeO3 nanoparticles which have been prepared by wet-chemical route. The average particle size found to be in the order of 45nm in which the chemical content of the unit cell has been verified. A distorted orthorhombic structure with Pbnm space group is possessed by this nanoparticle. From the bifurcation of ZFC and FC in low field, behavior of inverse susceptibility and the small hysteresis loop favors the material to be in a weak FM state well below the Neel temperature. The electrical behavior and the conduction mechanism above room temperature have been studied by cole-cole plot of the Impedance spectra. The high frequency depressed semi circles represent the grain conduction while the intermediate frequency semi circles appear may be due to grain boundary effect.

Multiplexed and scalable super-resolution imaging of three-dimensional protein localization in size-adjustable tissues.

PubMed

Ku, Taeyun; Swaney, Justin; Park, Jeong-Yoon; Albanese, Alexandre; Murray, Evan; Cho, Jae Hun; Park, Young-Gyun; Mangena, Vamsi; Chen, Jiapei; Chung, Kwanghun

2016-09-01

The biology of multicellular organisms is coordinated across multiple size scales, from the subnanoscale of molecules to the macroscale, tissue-wide interconnectivity of cell populations. Here we introduce a method for super-resolution imaging of the multiscale organization of intact tissues. The method, called magnified analysis of the proteome (MAP), linearly expands entire organs fourfold while preserving their overall architecture and three-dimensional proteome organization. MAP is based on the observation that preventing crosslinking within and between endogenous proteins during hydrogel-tissue hybridization allows for natural expansion upon protein denaturation and dissociation. The expanded tissue preserves its protein content, its fine subcellular details, and its organ-scale intercellular connectivity. We use off-the-shelf antibodies for multiple rounds of immunolabeling and imaging of a tissue's magnified proteome, and our experiments demonstrate a success rate of 82% (100/122 antibodies tested). We show that specimen size can be reversibly modulated to image both inter-regional connections and fine synaptic architectures in the mouse brain.

The geometry of proliferating dicot cells.

PubMed

Korn, R W

2001-02-01

The distributions of cell size and cell cycle duration were studied in two-dimensional expanding plant tissues. Plastic imprints of the leaf epidermis of three dicot plants, jade (Crassula argentae), impatiens (Impatiens wallerana), and the common begonia (Begonia semperflorens) were made and cell outlines analysed. The average, standard deviation and coefficient of variance (CV = 100 x standard deviation/average) of cell size were determined with the CV of mother cells less than the CV for daughter cells and both are less than that for all cells. An equation was devised as a simple description of the probability distribution of sizes for all cells of a tissue. Cell cycle durations as measured in arbitrary time units were determined by reconstructing the initial and final sizes of cells and they collectively give the expected asymmetric bell-shaped probability distribution. Given the features of unequal cell division (an average of 11.6% difference in size of daughter cells) and the size variation of dividing cells, it appears that the range of cell size is more critically regulated than the size of a cell at any particular time.

Fabrication of three-dimensional buckypaper catalyst layer with Pt nanoparticles supported on polyelectrolyte functionalized carbon nanotubes for proton exchange membrane fuel cells

NASA Astrophysics Data System (ADS)

Zhu, Shiyao; Zheng, Junsheng; Huang, Jun; Dai, Ningning; Li, Ping; Zheng, Jim P.

2018-07-01

Polyelectrolyte poly(diallyldimethylammonium chloride) (PDDA) functionalized carbon nanotubes (CNTs) supported Pt electrocatalyst was synthesized as a substitute for commonly used Pt/C and Pt/CNTs (modified by harsh acid-oxidation treatment) catalysts. In addition, this catalyst was fabricated as the cathode catalyst layer (CL) with a unique double-layered structure for proton exchange membrane fuel cells (PEMFCs). Thermogravimetric analysis shows an enhanced thermal stability of Pt/PDDA-CNTs. The Pt/PDDA-CNTs catalyst with an average Pt particle size of ∼3.1 nm exhibits the best electrocatalytic activity and a significantly enhanced electrochemical stability. Scanning electron microscope, energy dispersive spectrometer and mercury intrusion porosimetry results demonstrate the gradient distribution of Pt content and pore size along the thickness of buckypaper catalyst layer (BPCL). The accelerated degradation test results of BPCLs indicate that this gradient structure can ensure a high Pt utilization in the BPCLs (up to 90%) and further improve the catalyst durability. In addition, the membrane electrode assembly (MEA) fabricated with cathode BPCL-PDDA shows the best single cell performance and long-term stability, and a reduction of Pt loading can be achieved. The feasibility of BPCL for improving the Pt utilization is also demonstrated by the cathode cyclic voltammetry in MEA.

Probing the stochastic property of endoreduplication in cell size determination of Arabidopsis thaliana leaf epidermal tissue

PubMed Central

2017-01-01

Cell size distribution is highly reproducible, whereas the size of individual cells often varies greatly within a tissue. This is obvious in a population of Arabidopsis thaliana leaf epidermal cells, which ranged from 1,000 to 10,000 μm2 in size. Endoreduplication is a specialized cell cycle in which nuclear genome size (ploidy) is doubled in the absence of cell division. Although epidermal cells require endoreduplication to enhance cellular expansion, the issue of whether this mechanism is sufficient for explaining cell size distribution remains unclear due to a lack of quantitative understanding linking the occurrence of endoreduplication with cell size diversity. Here, we addressed this question by quantitatively summarizing ploidy profile and cell size distribution using a simple theoretical framework. We first found that endoreduplication dynamics is a Poisson process through cellular maturation. This finding allowed us to construct a mathematical model to predict the time evolution of a ploidy profile with a single rate constant for endoreduplication occurrence in a given time. We reproduced experimentally measured ploidy profile in both wild-type leaf tissue and endoreduplication-related mutants with this analytical solution, further demonstrating the probabilistic property of endoreduplication. We next extended the mathematical model by incorporating the element that cell size is determined according to ploidy level to examine cell size distribution. This analysis revealed that cell size is exponentially enlarged 1.5 times every endoreduplication round. Because this theoretical simulation successfully recapitulated experimentally observed cell size distributions, we concluded that Poissonian endoreduplication dynamics and exponential size-boosting are the sources of the broad cell size distribution in epidermal tissue. More generally, this study contributes to a quantitative understanding whereby stochastic dynamics generate steady-state biological heterogeneity. PMID:28926847

The effect of fibre content, fibre size and alkali treatment to Charpy impact resistance of Oil Palm fibre reinforced composite material

NASA Astrophysics Data System (ADS)

Fitri, Muhamad; Mahzan, Shahruddin

2016-11-01

In this research, the effect of fibre content, fibre size and alkali treatment to the impact resistance of the composite material have been investigated, The composite material employs oil palm fibre as the reinforcement material whereas the matrix used for the composite materials are polypropylene. The Oil Palm fibres are prepared for two conditions: alkali treated fibres and untreated fibres. The fibre sizes are varied in three sizes: 5mm, 7mm and 10mm. During the composite material preparation, the fibre contents also have been varied into 3 different percentages: 5%, 7% and 10%. The statistical approach is used to optimise the variation of specimen determined by using Taguchi method. The results were analyzed also by the Taguchi method and shows that the Oil Palm fibre content is significantly affect the impact resistance of the polymer matrix composite. However, the fibre size is moderately affecting the impact resistance, whereas the fibre treatment is insignificant to the impact resistance of the oil palm fibre reinforced polymer matrix composite.

[Polychlorinated biphenyls in fractions of wheat grains and in selected bakery products].

PubMed

Brandt, Elzbieta; Pietrzak-Fiećko, Renata; Smoczyński, S S

2012-01-01

Polychlorinated biphenyls (PCBs) form a group of synthetic aromatic chemical compounds, commonly occurring in the environment as a result of industrialisation. Despite the ban on PCBs production, their wide application in the past resulted in their common occurrence in all elements of the environment. The lipophilic nature of the compounds resulting in their accumulation in live organisms and in the human body may trigger many harmful effects. The aim of this study was to determine the PCBs content in the selected species of wheat and in bakery products. The studies aiming at confirming possible correlation between the size of the grain of the selected species of wheat and the content of polychlorinated biphenyls were presented in this paper. Moreover, PCBs concentration in cereals' grains and in bread was compared. The PCBs content was defined in different sizes of grains species of wheat i.e. Opatka, Zyta, Elena and Almari. The study included also two kinds of wheat bread. PCBs were determined after the extraction with n-hexane followed by sulphuric acid hydrolysis. Gas chromatography analysis was conducted on a PU 4600 Unicam apparatus with an electron capture detector. The large variations in PCBs content depending on the grain size were confirmed. In the Opatka species the increase in the content of all determined congeners and the size of grain was confirmed. The lowest PCBs concentrations were in smallest grains (0,0090 mg/kg of fat), and the highest in the largest grains (0,0264 mg/kg of fat). In Zyta species PCBs content was also lowest in the smallest grains, however these results were not statistically significant. In the Elena species the increase in the PCBs content together with the increase in the grain size was confirmed. Basing on the determination coefficient it was found that the concentration of PCBs depends on the size of grains in 24%. The highest concentration of PCBs (0,0366 mg/kg of fat) was found in the largest grains, however differences between the examined fractions were not statistically significant. Similar tendencies were observed in Almari species. PCBs content in wheat bread was on lower level than in all of the examined species. It was confirmed that fraction 2,8 x 25 mm of all species of wheat grain had the highest PCBs content. The tendency to decrease of PCBs content with the decrease of the grain in size was observed. The relation between qualitative class of species and PCBs content was not confirmed. There were statistically significant differences in the PCBs concentrations between the wheat species within one size fraction. The results of PCBs content in wheat bread were lower than in all examined species of wheat. One can assume that for the production of bread collected for the study, the wheat originating from areas with low PCBs contamination was used. Somewhat higher PCBs content was observed in the wheat bread with bran added, probably due to higher PCBs accumulation in the bran, which contain higher fat and contribute therefore to the overall PCBs in the bran containing bread.

The endothelial sample size analysis in corneal specular microscopy clinical examinations.

PubMed

Abib, Fernando C; Holzchuh, Ricardo; Schaefer, Artur; Schaefer, Tania; Godois, Ronialci

2012-05-01

To evaluate endothelial cell sample size and statistical error in corneal specular microscopy (CSM) examinations. One hundred twenty examinations were conducted with 4 types of corneal specular microscopes: 30 with each BioOptics, CSO, Konan, and Topcon corneal specular microscopes. All endothelial image data were analyzed by respective instrument software and also by the Cells Analyzer software with a method developed in our lab. A reliability degree (RD) of 95% and a relative error (RE) of 0.05 were used as cut-off values to analyze images of the counted endothelial cells called samples. The sample size mean was the number of cells evaluated on the images obtained with each device. Only examinations with RE < 0.05 were considered statistically correct and suitable for comparisons with future examinations. The Cells Analyzer software was used to calculate the RE and customized sample size for all examinations. Bio-Optics: sample size, 97 ± 22 cells; RE, 6.52 ± 0.86; only 10% of the examinations had sufficient endothelial cell quantity (RE < 0.05); customized sample size, 162 ± 34 cells. CSO: sample size, 110 ± 20 cells; RE, 5.98 ± 0.98; only 16.6% of the examinations had sufficient endothelial cell quantity (RE < 0.05); customized sample size, 157 ± 45 cells. Konan: sample size, 80 ± 27 cells; RE, 10.6 ± 3.67; none of the examinations had sufficient endothelial cell quantity (RE > 0.05); customized sample size, 336 ± 131 cells. Topcon: sample size, 87 ± 17 cells; RE, 10.1 ± 2.52; none of the examinations had sufficient endothelial cell quantity (RE > 0.05); customized sample size, 382 ± 159 cells. A very high number of CSM examinations had sample errors based on Cells Analyzer software. The endothelial sample size (examinations) needs to include more cells to be reliable and reproducible. The Cells Analyzer tutorial routine will be useful for CSM examination reliability and reproducibility.

Cell size is positively correlated between different tissues in passerine birds and amphibians, but not necessarily in mammals.

PubMed

Kozlowski, J; Czarnoleski, M; François-Krassowska, A; Maciak, S; Pis, T

2010-12-23

We examined cell size correlations between tissues, and cell size to body mass relationships in passerine birds, amphibians and mammals. The size correlated highly between all cell types in birds and amphibians; mammalian tissues clustered by size correlation in three tissue groups. Erythrocyte size correlated well with the volume of other cell types in birds and amphibians, but poorly in mammals. In birds, body mass correlated positively with the size of all cell types including erythrocytes, and in mammals only with the sizes of some cell types. Size of mammalian erythrocytes correlated with body mass only within the most taxonomically uniform group of species (rodents and lagomorphs). Cell volume increased with body mass of birds and mammals to less than 0.3 power, indicating that body size evolved mostly by changes in cell number. Our evidence suggests that epigenetic mechanisms determining cell size relationships in tissues are conservative in birds and amphibians, but less stringent in mammals. The patterns of cell size to body mass relationships we obtained challenge some key assumptions of fractal and cellular models used by allometric theory to explain mass-scaling of metabolism. We suggest that the assumptions in both models are not universal, and that such models need reformulation.

Iron and cell death in Parkinson's disease: a nuclear microscopic study into iron-rich granules in the parkinsonian substantia nigra of primate models

NASA Astrophysics Data System (ADS)

Thong, P. S. P.; Watt, F.; Ponraj, D.; Leong, S. K.; He, Y.; Lee, T. K. Y.

1999-10-01

Parkinson's disease is a degenerative brain disease characterised by a loss of cells in the substantia nigra (SN) region of the brain and accompanying biochemical changes such as inhibition of mitochondrial function, increased iron concentrations and decreased glutathione levels in the parkinsonian SN. Though the aetiology of the disease is still unknown, the observed biochemical changes point to the involvement of oxidative stress. In particular, iron is suspected to play a role by promoting free radical production, leading to oxidative stress and cell death. The increase in iron in the parkinsonian SN has been confirmed by several research groups, both in human post-mortem brains and in brain tissue from parkinsonian animal models. However, the question remains as to whether the observed increase in iron is a cause or a consequence of the SN cell death process. Our previous study using unilaterally 1-methyl-4-phenyl-1,2,3,6-tetrahydro-pyridine (MPTP)-lesioned monkeys in a time sequence experiment has shown that the increase in bulk iron concentrations follow rather than precede dopaminergic cell death. However, changes in the localised iron concentrations, which may play a more direct role in SN cell death, may not be reflected at the bulk level. Indeed, we have observed iron-rich granules in parkinsonian SNs. From this time sequence study into the iron content of iron-rich granules in the SNs of an untreated control and unilaterally MPTP-lesioned parkinsonian models, we present the following observations: (1) Iron-rich granules are found in both control and parkinsonian SNs and are variable in size and iron content in any one model. (2) These iron-rich granules may be associated with neuromelanin granules found in the SN and are known to accumulate transition metal ions such as iron. (3) The early onset of bulk SN cell loss (35%) was accompanied by a significant elevation of iron in granules found in the MPTP-injected SN compared to the contra-lateral SN. This shows that localised iron increase may be an early event contributing to cell death. (4) The iron content in granules found in both the MPTP-injected and contra-lateral SNs is correlated with the degree of bulk SN cell loss (assessed by TH-immunohistochemistry) in individual models. This indicates a correlation between localised iron increase and cell loss, at least at the whole SN level. Our results are consistent with the observation that in Parkinson's disease (PD), neuronal cell death seems to be related to their neuromelanin content and support the proposal that iron-melanin interaction may play a role in oxidative neuronal cell death. Indeed, iron-saturated neuromelanin granules may act as centres of free radical production, contributing to localised cell death.

DNA Content Differences Between Male and Female Chicken (Gallus gallus domesticus) Nuclei and Z and W Chromosomes Resolved by Image Cytometry

PubMed Central

Mendonça, Maria Andréia Corrêa; Carvalho, Carlos Roberto; Clarindo, Wellington Ronildo

2010-01-01

Chicken red blood cells (CRBCs) are widely used as standards for DNA content determination. Cytogenetic data have shown that the Z sex chromosome is approximately twice as large as the W, so that the DNA content differs to some extent between male (ZZ) and female (ZW) chickens. Despite this fact, male and female CRBCs have been indiscriminately used in absolute genome size determination. Our work was conducted to verify whether the DNA content differences between male and female Gallus gallus domesticus “Leghorn” nuclei and ZZ/ZW chromosomes can be resolved by image cytometry (ICM). Air-dried smears stained by Feulgen reaction were used for nuclei analysis. Chicken metaphase spreads upon Feulgen staining were analyzed for obtaining quantitative information on the Z and W chromosomes. Before each capture session, we conducted quality control of the ICM instrumentation. Our results from nuclear measurements showed that the 2C value is 0.09 pg higher in males than in females. In chromosomes, we found that the Z chromosome shows 200% more DNA content than does the W chromosome. ICM demonstrated resolution power to discriminate low DNA content differences in genomes. We suggest prudence in the general use of CRBC 2C values as standards in comparative cytometric analysis. (J Histochem Cytochem 58:229–235, 2010) PMID:19875846

Geochemical heterogeneity in a sand and gravel aquifer: Effect of sediment mineralogy and particle size on the sorption of chlorobenzenes

USGS Publications Warehouse

Barber, L.B.; Thurman, E.M.; Runnells, D.R.; ,

1992-01-01

The effect of particle size, mineralogy and sediment organic carbon (SOC) on solution of tetrachlorobenzene and pentachlorobenzene was evaluated using batch-isotherm experiments on sediment particle-size and mineralogical fractions from a sand and gravel aquifer, Cape Cod, Massachusetts. Concentration of SOC and sorption of chlorobenzenes increase with decreasing particle size. For a given particle size, the magnetic fraction has a higher SOC content and sorption capacity than the bulk or non-magnetic fractions. Sorption appears to be controlled by the magnetic minerals, which comprise only 5-25% of the bulk sediment. Although SOC content of the bulk sediment is < 0.1%, the observed sorption of chlorobenzenes is consistent with a partition mechanism and is adequately predicted by models relating sorption to the octanol/water partition coefficient of the solute and SOC content. A conceptual model based on preferential association of dissolved organic matter with positively-charged mineral surfaces is proposed to describe micro-scale, intergranular variability in sorption properties of the aquifer sediments.The effect of particle size, mineralogy and sediment organic carbon (SOC) on sorption of tetrachlorobenzene and pentachlorobenzene was evaluated using batch-isotherm experiments on sediment particle-size and mineralogical fractions from a sand and gravel aquifer, Cape Cod, Massachusetts. Concentration of SOC and sorption of chlorobenzenes increase with decreasing particle size. For a given particle size, the magnetic fraction has a higher SOC content and sorption capacity than the bulk or non-magnetic fractions. Sorption appears to be controlled by the magnetic minerals, which comprise only 5-25% of the bulk sediment. Although SOC content of the bulk sediment is <0.1%, the observed sorption of chlorobenzenes is consistent with a partition mechanism and is adequately predicted by models relating sorption to the octanol/water partition coefficient of the solute and SOC content. A conceptual model based on preferential association of dissolved organic matter with positively-charged mineral surfaces is proposed to describe micro-scale, intergranular variability in sorption properties of the aquifer sediments.

Toxicity of drinking water disinfection byproducts: cell cycle alterations induced by the monohaloacetonitriles.

PubMed

Komaki, Yukako; Mariñas, Benito J; Plewa, Michael J

2014-10-07

Haloacetonitriles (HANs) are a chemical class of drinking water disinfection byproducts (DBPs) that form from reactions between disinfectants and nitrogen-containing precursors, the latter more prevalent in water sources impacted by algae bloom and municipal wastewater effluent discharge. HANs, previously demonstrated to be genotoxic, were investigated for their effects on the mammalian cell cycle. Treating Chinese hamster ovary (CHO) cells with monoHANs followed by the release from the chemical treatment resulted in the accumulation of abnormally high DNA content in cells over time (hyperploid). The potency for the cell cycle alteration followed the order: iodoacetonitrile (IAN) > bromoacetonitrile (BAN) ≫ chloroacetonitrile (CAN). Exposure to 6 μM IAN, 12 μM BAN and 900 μM CAN after 26 h post-treatment incubation resulted in DNA repair; however, subsequent cell cycle alteration effects were observed. Cell proliferation of HAN-treated cells was suppressed for as long as 43 to 52 h. Enlarged cell size was observed after 52 h post-treatment incubation without the induction of cytotoxicity. The HAN-mediated cell cycle alteration was mitosis- and proliferation-dependent, which suggests that HAN treatment induced mitosis override, and that HAN-treated cells proceeded into S phase and directly into the next cell cycle. Cells with multiples genomes would result in aneuploidy (state of abnormal chromosome number and DNA content) at the next mitosis since extra centrosomes could compromise the assembly of bipolar spindles. There is accumulating evidence of a transient tetraploid state proceeding to aneuploidy in cancer progression. Biological self-defense systems to ensure genomic stability and to eliminate tetraploid cells exist in eukaryotic cells. A key tumor suppressor gene, p53, is oftentimes mutated in various types of human cancer. It is possible that HAN disruption of the normal cell cycle and the generation of aberrant cells with an abnormal number of chromosomes may contribute to cancer induction and perhaps be involved in the induction of adverse pregnancy outcomes associated with long-term consumption of disinfected water. Here we present the first observation of the induction of hyperploidy by a class of DBPs.

In vitro characterization of self-assembled anterior cruciate ligament cell spheroids for ligament tissue engineering.

PubMed

Hoyer, M; Meier, C; Breier, A; Hahner, J; Heinrich, G; Drechsel, N; Meyer, M; Rentsch, C; Garbe, L-A; Ertel, W; Lohan, A; Schulze-Tanzil, G

2015-03-01

Tissue engineering of an anterior cruciate ligament (ACL) implant with functional enthesis requires site-directed seeding of different cell types on the same scaffold. Therefore, we studied the suitability of self-assembled three-dimensional spheroids generated by lapine ACL ligament fibroblasts for directed scaffold colonization. The spheroids were characterized in vitro during 14 days in static and 7 days in dynamic culture. Size maintenance of self-assembled spheroids, the vitality, the morphology and the expression pattern of the cells were monitored. Additionally, we analyzed the total sulfated glycosaminoglycan, collagen contents and the expression of the ligament components type I collagen, decorin and tenascin C on protein and for COL1A1, DCN and TNMD on gene level in the spheroids. Subsequently, the cell colonization of polylactide-co-caprolactone [P(LA-CL)] and polydioxanone (PDS) polymer scaffolds was assessed in response to a directed, spheroid-based seeding technique. ACL cells were able to self-assemble spheroids and survive over 14 days. The spheroids decreased in size but not in cellularity depending on the culture time and maintained or even increased their differentiation state. The area of P[LA-CL] scaffolds, colonized after 14 days by the cells of one spheroid, was in average 4.57 ± 2.3 mm(2). Scaffolds consisting of the polymer P[LA-CL] were more suitable for colonization by spheroids than PDS embroideries. We conclude that ACL cell spheroids are suitable as site-directed seeding strategy for scaffolds in ACL tissue engineering approaches and recommend the use of freshly assembled spheroids for scaffold colonization, due to their balanced proliferation and differentiation.

Scaling of number, size, and metabolic rate of cells with body size in mammals.

PubMed

Savage, Van M; Allen, Andrew P; Brown, James H; Gillooly, James F; Herman, Alexander B; Woodruff, William H; West, Geoffrey B

2007-03-13

The size and metabolic rate of cells affect processes from the molecular to the organismal level. We present a quantitative, theoretical framework for studying relationships among cell volume, cellular metabolic rate, body size, and whole-organism metabolic rate that helps reveal the feedback between these levels of organization. We use this framework to show that average cell volume and average cellular metabolic rate cannot both remain constant with changes in body size because of the well known body-size dependence of whole-organism metabolic rate. Based on empirical data compiled for 18 cell types in mammals, we find that many cell types, including erythrocytes, hepatocytes, fibroblasts, and epithelial cells, follow a strategy in which cellular metabolic rate is body size dependent and cell volume is body size invariant. We suggest that this scaling holds for all quickly dividing cells, and conversely, that slowly dividing cells are expected to follow a strategy in which cell volume is body size dependent and cellular metabolic rate is roughly invariant with body size. Data for slowly dividing neurons and adipocytes show that cell volume does indeed scale with body size. From these results, we argue that the particular strategy followed depends on the structural and functional properties of the cell type. We also discuss consequences of these two strategies for cell number and capillary densities. Our results and conceptual framework emphasize fundamental constraints that link the structure and function of cells to that of whole organisms.

Biodegradable poly(vinyl alcohol)/polyoxalate electrospun nanofibers for hydrogen peroxide-triggered drug release.

PubMed

Phromviyo, Nutthakritta; Lert-Itthiporn, Aurachat; Swatsitang, Ekaphan; Chompoosor, Apiwat

2015-01-01

Release of drugs in a controlled and sustainable manner is of great interest for treating some inflammatory diseases, drug delivery, and cosmetics. In this work, we demonstrated the control release of a drug from composite nanofibers mediated by hydrogen peroxide. Composite nanofibers of polyvinyl alcohol (PVA)/polyoxalate (PVA/POX NFs) blended at various weight ratios were successfully prepared by electrospinning. Rhodamine B (RB) was used as a model of drug and was initially loaded into the POX portion. The morphology of NFs was characterized using scanning electron microscopy (SEM). The functional groups presented in the NFs were characterized using IR spectroscopy. In vitro release behavior and cell toxicity of nanofibers were also investigated using the MTT assay. The results indicated that POX content had a significant effect on the size and release profiles of nanofibers. Microstructure analysis revealed that sizes of PVA/POX NFs increased with increasing POX content, ranging from 214 to 422 nm. Release profiles of RB at 37 °C were non-linear and showed different release mechanisms. The mechanism of drug release depended on the chemical composition of the NFs. RB release from the NFs with highest POX content was caused by the degradation of the nanofiber matrix, whereas the RB release in lower POX content NFs was caused by diffusion. The NFs with POX showed a loss of structural integrity in the presence of hydrogen peroxide as seen using SEM. The MTT assay showed that composite nanofibers had minimal cytotoxicity. We anticipate that nanofibrous PVA/POX can potentially be used to target numerous inflammatory diseases that overproduce hydrogen peroxide and may become a potential candidate for use as a local drug delivery vehicle.

Simultaneous silencing of isoamylases ISA1, ISA2 and ISA3 by multi-target RNAi in potato tubers leads to decreased starch content and an early sprouting phenotype

PubMed Central

Ferreira, Stephanus J.; Senning, Melanie; Fischer-Stettler, Michaela; Streb, Sebastian; Ast, Michelle; Neuhaus, H. Ekkehard; Zeeman, Samuel C.; Sonnewald, Sophia

2017-01-01

Isoamylases hydrolyse (1–6)-alpha-D-glucosidic linkages in starch and are involved in both starch granule formation and starch degradation. In plants, three isoamylase isoforms with distinct functions in starch synthesis (ISA1 and ISA2) and degradation (ISA3) have been described. Here, we created transgenic potato plants with simultaneously decreased expression of all three isoamylases using a chimeric RNAi construct targeting all three isoforms. Constitutive expression of the hairpin RNA using the 35S CaMV promoter resulted in efficient silencing of all three isoforms in leaves, growing tubers, and sprouting tubers. Neither plant growth nor tuber yield was effected in isoamylase-deficient potato lines. Interestingly, starch metabolism was found to be impaired in a tissue-specific manner. While leaf starch content was unaffected, tuber starch was significantly reduced. The reduction in tuber starch content in the transgenic plants was accompanied by a decrease in starch granules size, an increased sucrose content and decreased hexose levels. Despite the effects on granule size, only little changes in chain length composition of soluble and insoluble glucose polymers were detected. The transgenic tubers displayed an early sprouting phenotype that was accompanied by an increased level of sucrose in parenchyma cells below the outgrowing bud. Since high sucrose levels promote sprouting, we propose that the increased number of small starch granules may cause an accelerated turnover of glucan chains and hence a more rapid synthesis of sucrose. This observation links alterations in starch structure/degradation with developmental processes like meristem activation and sprout outgrowth in potato tubers. PMID:28708852

Alterations of DNA content in human endometrial stromal cells transfected with a temperature-sensitive SV40: tetraploidization and physiological consequences.

PubMed

Rinehart, C A; Mayben, J P; Butler, T D; Haskill, J S; Kaufman, D G

1992-01-01

The normal genomic stability of human cells is reversed during neoplastic transformation. The SV40 large T antigen alters the DNA content in human endometrial stromal cells in a manner that relates to neoplastic progression. Human endometrial stromal cells were transfected with a plasmid containing the A209 temperature-sensitive mutant of SV40 (tsSV40), which is also defective in the viral origin of replication. Ninety-seven clonal transfectants from seven different primary cell strains were isolated. Initial analysis revealed that 20% of the clonal populations (19/97) had an apparent diploid DNA content, 35% (34/97) had an apparent tetraploid DNA content, and the remainder were mixed populations of diploid and tetraploid cells. No aneuploid populations were observed. Diploid tsSV40 transformed cells always give rise to a population of cells with a tetraploid DNA content when continuously cultured at the permissive temperature. The doubling of DNA content can be vastly accelerated by the sudden reintroduction of large T antigen activity following a shift from non-permissive to permissive temperature. Tetraploid tsSV40 transfected cells have a lower capacity for anchorage-independent growth and earlier entry into 'crisis' than diploid cells. These results indicate that during the pre-crisis, extended lifespan phase of growth, the SV40 large T antigen causes a doubling of DNA content. This apparent doubling of DNA content does not confer growth advantage during the extended lifespan that precedes 'crisis'.

13C NMR spectroscopy characterization of particle-size fractionated soil organic carbon in subalpine forest and grassland ecosystems.

PubMed

Shiau, Yo-Jin; Chen, Jenn-Shing; Chung, Tay-Lung; Tian, Guanglong; Chiu, Chih-Yu

2017-12-01

Soil organic carbon (SOC) and carbon (C) functional groups in different particle-size fractions are important indicators of microbial activity and soil decomposition stages under wildfire disturbances. This research investigated a natural Tsuga forest and a nearby fire-induced grassland along a sampling transect in Central Taiwan with the aim to better understand the effect of forest wildfires on the change of SOC in different soil particle scales. Soil samples were separated into six particle sizes and SOC was characterized by solid-state 13 C nuclear magnetic resonance spectroscopy in each fraction. The SOC content was higher in forest than grassland soil in the particle-size fraction samples. The O-alkyl-C content (carbohydrate-derived structures) was higher in the grassland than the forest soils, but the alkyl-C content (recalcitrant substances) was higher in forest than grassland soils, for a higher humification degree (alkyl-C/O-alkyl-C ratio) in forest soils for all the soil particle-size fractions. High humification degree was found in forest soils. The similar aromaticity between forest and grassland soils might be attributed to the fire-induced aromatic-C content in the grassland that offsets the original difference between the forest and grassland. High alkyl-C content and humification degree and low C/N ratios in the fine particle-size fractions implied that undecomposed recalcitrant substances tended to accumulate in the fine fractions of soils.

A sensitive cytochemical staining method for glucose-6-phosphate dehydrogenase activity in individual erythrocytes. II. Further improvements of the staining procedure and some observations with glucose-6-phosphate dehydrogenase deficiency.

PubMed

Van Noorden, C J; Vogels, I M

1985-05-01

A cytochemical method for staining glucose-6-phosphate dehydrogenase (G6PD) activity in individual erythrocytes as reported previously has been optimized further by the incorporation of a number of technical improvements. Analysis of the enzyme content in erythrocytes of normal individuals as well as patients suffering from G6PD deficiency in the homozygous and heterozygous forms allows these three categories to be easily distinguished. Considerable formazan production occurs in most erythrocytes of a healthy person and only a small percentage of the cells appeared to be negative. Two cell populations of almost equal size could be discerned in heterozygotes for G6PD deficiency, one completely negative, the other with a variable amount of formazan per cell. Homozygous deficiency leads to a population of negative cells with a few positive ones after staining. It is concluded that a reliable method has been found for analysis of G6PD deficiency in erythrocytes at the single cell level.

Applications of microfluidics in microalgae biotechnology: A review.

PubMed

Juang, Yi-Je; Chang, Jo-Shu

2016-03-01

Microalgae have been one of the important sources for biofuel production owing to their competitive advantages such as no need to tap into the global food supply chain, higher energy density, and absorbing carbon dioxide to mitigate global warming. One of the key factors to ensure successful biofuel production is that it requires not only bioprospecting of the microalgae with high lipid content, high growth rate and tolerance to environmental parameters but also on-site monitoring of the cultivation process and optimization of the culturing conditions. However, as the conventional techniques usually involve in complicated procedures, or are time-consuming or labor intensive, microfluidics technology offers an attractive alternative to resolve these issues. In this review, applications of microfluidics to bioprospecting in microalgae biotechnology were discussed such as cell identification, cell sorting/screening, cell culturing and cell disruption. In addition, utilization of microalgae in micro-sized fuel cells and microfluidic platforms for biosensing was addressed. This review reports the recent studies and offers a look into how microfluidics is exploited to tackle the issues encountered in the microalgae biotechnology. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Frying of the Dispersion Droplets with Varying Contents of Chickpea Flour and Gum Arabic: Product Characterization and Modeling.

PubMed

Shanthilal, J; Babylatha, R; Navya, M C; Chakkaravarthi, A; Bhattacharya, Suvendu

2018-03-01

Dispersions having chickpea (37%, 40%, and 43%, w/w) and gum arabic (0%, 1%, 2%, 3%, 4%, and 5%, w/w) solids were prepared. These dispersion droplets were fried, and the physical, sensory, and microstructural characteristics of the fried products were determined. The oil content in the fried snack decreased up to 20.3% when the level of chickpea and/or gum in the dispersions was increased. The compression curve for fried snack showed 5 major zones and exhibited the failure phenomenon. Failure force (6.5 to 11.4 N) increased with chickpea flour in the dispersions. Fracture strain (12.0% to 19.5%) indicated that all the fried samples were soft-crisp products. An increase in chickpea flour concentration offered an ovoid/oblong shape of dispersion droplets while falling to oil, and changed the spherical shape of the fried snack. The near-spherical product could be obtained by using 37% chickpea flour containing 0 to 2% of gum arabic, or with the 40% and 0 to 1% combinations. The hue or dominant wavelength increased from 578.5 nm (flour) to 581.0 to 582.7 nm (product) indicating a shift toward red coloration. A porous microstructure with scattered small cavities and large vacuoles of the fried snack were observed; big vacuoles were located in the inner portion of the fried product. The cells were divided into closed and open cells and were characterized by image analysis. The air cells usually had an elliptical shape with varying sizes; the cell wall thickness was between 12 and 80 μm. An artificial neural network (ANN) structure of 2-9-2 was developed for the prediction of sensory overall acceptability and oil content of the fried snack. Chickpea flour is used in several food preparations. The addition of gum arabic affects the textural and structural characteristics, and the sensory acceptance; the fried dispersion droplets have a lower fat content when gum arabic is used compared to samples fried without the addition of gum arabic. The fried dispersion droplets change their shape with the level of the ingredients used in the dispersion. © 2018 Institute of Food Technologists®.

Islets of Langerhans in the parakeet, Psittacula krameri.

PubMed

Gupta, Y K; Kumar, S

1980-01-01

The pancreatic gland of Psittacula krameri is divisible into 4 lobes i.e. dorsal, ventral, third and splenic. The endocrine part is composed of alpha 1-, alpha 2- and beta-cells. The islets are of 4 kinds viz., alpha islets (having alpha 1- and alpha 2-cells), beta islets (having beta- and alpha 1-cells), pure beta islets (consisting of beta-cells exclusively) and mixed islets (with beta-, alpha 1- and alpha 2-cells). The distribution of alpha islets is mostly restricted to the splenic and third lobes whereas the beta islets are found in all 4 lobes. Though the alpha islets are only few in the dorsal lobe, their size is best developed in the third and dorsal lobes. Sometimes beta and alpha islets are present in very close proximity but their cells never mingle. An interesting feature was the complete absence of alpha islets from the ventral lobe.A relative abundance of alpha 2- cells in this bird seems to be associated with its comparatively higher blood glucose level and frugivorous habit. Tinctorial reactions suggest that the insulin content of the endocrine pancreas is low. There were no seasonal changes in the islet tissue of P. krameri.

Silymarin improves the behavioural, biochemical and histoarchitecture alterations in focal ischemic rats: a comparative evaluation with piracetam and protocatachuic acid.

PubMed

Muley, Milind M; Thakare, Vishnu N; Patil, Rajesh R; Kshirsagar, Ajay D; Naik, Suresh R

2012-08-01

Comparative neuroprotective potential of silymarin, piracetam and protocatechuic acid ethyl ester (PCA) was evaluated in focal ischemic rats. Various pharmacological, biochemical (lipid peroxidation, reduced glutathione, catalase, nitrite content, brain water content) and behavioural (memory impairment, motor control, neurological score) including infarct size and histopathological alterations were evaluated. Silymarin (200mg/kg) and PCA treatment significantly improved behavioural, biochemical and histopathological changes, and reduced water content and infarct size. However, piracetam only improved behavioural and histopathological changes, reduced water content and infarct size. The findings indicate that silymarin exhibits neuroprotective activity better than PCA and piracetam in focal ischemia/reperfusion reflected by its better restoration of behavioural and antioxidant profile. Copyright © 2012 Elsevier Inc. All rights reserved.

Superior in vitro biological response and mechanical properties of an implantable nanostructured biomaterial: Nanohydroxyapatite-silicone rubber composite.

PubMed

Thein-Han, W W; Shah, J; Misra, R D K

2009-09-01

A potential approach to achieving the objective of favorably modulating the biological response of implantable biopolymers combined with good mechanical properties is to consider compounding the biopolymer with a bioactive nanocrystalline ceramic biomimetic material with high surface area. The processing of silicone rubber (SR)-nanohydroxyapatite (nHA) composite involved uniform dispersion of nHA via shear mixing and ultrasonication, followed by compounding at sub-ambient temperature, and high-pressure solidification when the final curing reaction occurs. The high-pressure solidification approach enabled the elastomer to retain the high elongation of SR even in the presence of the reinforcement material, nHA. The biological response of the nanostructured composite in terms of initial cell attachment, cell viability and proliferation was consistently greater on SR-5wt.% nHA composite surface compared to pure SR. Furthermore, in the nanocomposite, cell spreading, morphology and density were distinctly different from that of pure SR. Pre-osteoblasts grown on SR-nHA were well spread, flat, large in size with a rough cell surface, and appeared as a group. In contrast, these features were less pronounced in SR (e.g. smooth cell surface, not well spread). Interestingly, an immunofluorescence study illustrated distinct fibronectin expression level, and stronger vinculin focal adhesion contacts associated with abundant actin stress fibers in pre-osteoblasts grown on the nanocomposite compared to SR, implying enhanced cell-substrate interaction. This finding was consistent with the total protein content and SDS-PAGE analysis. The study leads us to believe that further increase in nHA content in the SR matrix beyond 5wt.% will encourage even greater cellular response. The integration of cellular and molecular biology with materials science and engineering described herein provides a direction for the development of a new generation of nanostructured materials.

Intraspecific variation in egg size and egg composition in birds: effects on offspring fitness.

PubMed

Williams, T D

1994-02-01

1. There is little unequivocal evidence to date in support of a positive relationship between egg size and offspring fitness in birds. Although 40 studies (of 34 species) have considered the effect of variation in egg size on chick growth and/or survival up to fledgling only 12 studies have controlled for other characters potentially correlated both with egg size and offspring fitness. Of these only two have reported a significant residual effect of egg size on chick growth (in the roseate tern and European blackbird) and three a residual effect on chick survival (all in seabirds: common tern, lesser black-backed gull and kittiwake). 2. More consistent evidence exists, though from fewer studies, for a positive relationship between egg size and offspring fitness early in the chick-rearing period; chick growth and chick survival being dependent on egg size in 8 of 10 studies and 4 of 5 studies respectively. It is suggested that the most important effect of variation in egg size might be in determining the probability of offspring survival in the first few days after hatching. 3. Egg size explains on average 66% of the variation in chick mass at hatching (n = 35 studies) but only 30% of the variation in chick body size (n = 18). When effects of hatching body size are controlled for chick mass remains significantly correlated with egg size, though the reverse is not true. This supports the hypothesis that large eggs give rise to heavier chicks at hatching, i.e., chicks with more nutrient (yolk) reserves, rather than structurally larger chicks. 4. Egg composition increased isometrically with increasing egg size in about half the studies so far reported (n equals approximately 20). However, in seabirds, and some passerines, larger eggs contain disproportionately more albumen, whilst in some waterfowl percentage yolk content increases with increasing egg size. Changes in albumen content largely reflect variation in the water content of eggs, but changes in yolk content involve variation in lipid content, and therefore in egg 'quality.' The adaptive significance of variation in egg composition is considered; females may adjust egg composition facultatively to maximise the benefits to their offspring of increased reproductive investment. 5. Considerations for future research are discussed with particular emphasis on experimental studies and the application of new techniques.

Characterization of Cross-Linked Porous Gelatin Carriers and Their Interaction with Corneal Endothelium: Biopolymer Concentration Effect

PubMed Central

Lai, Jui-Yang; Ma, David Hui-Kang; Lai, Meng-Heng; Li, Ya-Ting; Chang, Ren-Jie; Chen, Li-Mei

2013-01-01

Cell sheet-mediated tissue regeneration is a promising approach for corneal reconstruction. However, the fragility of bioengineered corneal endothelial cell (CEC) monolayers allows us to take advantage of cross-linked porous gelatin hydrogels as cell sheet carriers for intraocular delivery. The aim of this study was to further investigate the effects of biopolymer concentrations (5–15 wt%) on the characteristic and safety of hydrogel discs fabricated by a simple stirring process combined with freeze-drying method. Results of scanning electron microscopy, porosity measurements, and ninhydrin assays showed that, with increasing solid content, the pore size, porosity, and cross-linking index of carbodiimide treated samples significantly decreased from 508±30 to 292±42 µm, 59.8±1.1 to 33.2±1.9%, and 56.2±1.6 to 34.3±1.8%, respectively. The variation in biopolymer concentrations and degrees of cross-linking greatly affects the Young’s modulus and swelling ratio of the gelatin carriers. Differential scanning calorimetry measurements and glucose permeation studies indicated that for the samples with a highest solid content, the highest pore wall thickness and the lowest fraction of mobile water may inhibit solute transport. When the biopolymer concentration is in the range of 5–10 wt%, the hydrogels have high freezable water content (0.89–0.93) and concentration of permeated glucose (591.3–615.5 µg/ml). These features are beneficial to the in vitro cultivation of CECs without limiting proliferation and changing expression of ion channel and pump genes such as ATP1A1, VDAC2, and AQP1. In vivo studies by analyzing the rabbit CEC morphology and count also demonstrate that the implanted gelatin discs with the highest solid content may cause unfavorable tissue-material interactions. It is concluded that the characteristics of cross-linked porous gelatin hydrogel carriers and their triggered biological responses are in relation to biopolymer concentration effects. PMID:23382866

Effect of particle size and ammonium sulfate concentration on rice bran fermentation with the fungus Rhizopus oryzae.

PubMed

Schmidt, Cristiano Gautério; Furlong, Eliana Badiale

2012-11-01

The effects of rice bran particle size (0.18-0.39mm) and ammonium sulfate concentration in the nutrient solution (2-8g/L) on biomass production, protein and phenolic content generated by solid state fermentation with the fungus Rhizopus oryzae (CCT 1217) were studied. Particle size had a positive effect on biomass production and a negative effect (p⩽0.05) on protein and phenolic contents. Ammonium sulfate concentration had a positive effect (p⩽0.05) on biomass and phenolic content gain. Cultivation of fungus in rice bran with particle size of 0.18mm and in the presence of 8g/L ammonium sulfate, resulted in protein levels of 20g/100g dry wt and phenolics content of 4mg/g dry wt. These values were 53 and 65% higher than those achieved with unfermented rice bran. The results demonstrate that the fermentation process increased the value of compounds recovered for potential use in food formulations. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of MUF/Epoxy Microcapsules on Mechanical Properties and Fractography of Epoxy Materials

NASA Astrophysics Data System (ADS)

Ni, Zhuo; Lin, Yuhao; Du, Xuexiao

2017-12-01

Melamine-urea-formaldehyde (MUF) microcapsules were synthesized, morphology, shell thickness, average diameter and interface morphology were studied by scanning electron microscope (SEM). The spherical MUF microcapsules are size normal distribution without adhesion and accumulation, being compact, rough and uneven with a thickness of 3.2μm and a core contents is approximate 70%. A latent imidazoleas the curing agent for a cross-linking chemical reaction for cracking repairing. A good dispersion of MUF microcapsules and a good interfacial bonding are obtained. Effects of MUF microcapsule size and content on bending property and dynamic mechanical propertywere investigated. Both bending strength and storage modulus of the composite are considerably reduced with an increasing addition of the microcapsules whereas the glass transition temperatures are almost not influenced. Significant toughening effects of MUF microcapsules on the epoxy composites are observed at the conditions of different content and size of microcapsule especially at low microcapsule contents and small microcapsule sizes.

Cell damage and death by autoschizis in human bladder (RT4) carcinoma cells resulting from treatment with ascorbate and menadione.

PubMed

Gilloteaux, Jacques; Jamison, James M; Neal, Deborah R; Loukas, Marios; Doberzstyn, Theresa; Summers, Jack L

2010-05-01

A human bladder carcinoma cell line RT4 was sham-treated with buffer or treated with ascorbate (VC) alone, menadione alone (VK(3)), or a combination of ascorbate:menadione (VC+VK(3)) for 1, 2, and 4 h. Cytotoxic damage was found to be treatment-dependent in this sequence: VC+VK(3)>VC>VK(3)>sham. The combined treatment induced the greatest oxidative stress, with early tumor cell injury affecting the cytoskeletal architecture and contributing to the self-excisions of pieces of cytoplasm freed from organelles. Additional damage, including a reduction in cell size, organelle alterations, nuclear damage, and nucleic acid degradation as well as compromised lysosome integrity, is caused by reactivation of DNases and the redox cycling of VC or VC+VK(3). In addition, cell death caused by VC+VK(3) treatment as well as by prolonged VC treatment is consistent with cell demise by autoschizis, not apoptosis. This report confirms and complements previous observations about this new mode of tumor cell death. It supports the contention that a combination of VC+VK(3), also named Apatone, could be co-administered as a nontoxic adjuvant with radiation and/or chemotherapies to kill bladder tumor cells and other cancer cells without any supplementary risk or side effects for patients.