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Sample records for aerobically grown cells

  1. Proteome analysis of aerobically and anaerobically grown Saccharomyces cerevisiae cells.

    PubMed

    Bruckmann, Astrid; Hensbergen, Paul J; Balog, Crina I A; Deelder, André M; Brandt, Raymond; Snoek, I S Ishtar; Steensma, H Yde; van Heusden, G Paul H

    2009-01-30

    The yeast Saccharomyces cerevisiae is able to grow under aerobic as well as anaerobic conditions. We and others previously found that transcription levels of approximately 500 genes differed more than two-fold when cells from anaerobic and aerobic conditions were compared. Here, we addressed the effect of anaerobic growth at the post-transcriptional level by comparing the proteomes of cells isolated from steady-state glucose-limited anaerobic and aerobic cultures. Following two-dimensional gel electrophoresis and mass spectrometry we identified 110 protein spots, corresponding to 75 unique proteins, of which the levels differed more than two-fold between aerobically and anaerobically-grown cells. For 21 of the 110 spots, the intensities decreased more than two-fold whereas the corresponding mRNA levels increased or did not change significantly under anaerobic conditions. The intensities of the other 89 spots changed in the same direction as the mRNA levels of the corresponding genes, although to different extents. For some genes of glycolysis a small increase in mRNA levels, 1.5-2 fold, corresponded to a 5-10 fold increase in protein levels. Extrapolation of our results suggests that transcriptional regulation is the major but not exclusive mechanism for adaptation of S. cerevisiae to anaerobic growth conditions.

  2. Differential effects of hydrogen peroxide and ascorbic acid on the aerobic thermosensitivity of yeast cells grown under aerobic and anoxic conditions.

    PubMed

    Moraitis, Christos; Curran, Brendan P G

    2010-02-01

    We have previously demonstrated that in aerobically-grown cells of the yeast Saccharomyces cerevisiae, hydrogen peroxide (H(2)O(2)) increases and ascorbic acid decreases cellular thermosensitivity, as determined by the inducibility of a heat shock (HS)-reporter gene. In this work, we reveal that the aerobic thermosensitivity of anaerobically-grown yeast cells also increases in the presence of H(2)O(2), albeit differentially between cells with two different lipid profiles. In comparison to aerobically-grown fermenting cells treated with the same H(2)O(2) concentration, both these types of anaerobically-grown cells were found to be considerably less sensitive to aerobic heat shock and considerably more thermotolerant. Paradoxically, and in contrast to ascorbate-pretreated aerobically-grown yeast cells, when anaerobically-grown cells were heat-shocked aerobically in the presence of the same ascorbic acid concentration, they exhibited increased thermosensitivity and decreased intrinsic thermotolerance with respect to their untreated counterparts. These findings are discussed with respect to what is currently known about the redox and physiological status of yeast cells grown aerobically and cells reoxygenated following anoxic growth.

  3. Toxic and inhibitory effects of trichloroethylene aerobic co-metabolism on phenol-grown aerobic granules.

    PubMed

    Zhang, Yi; Tay, JooHwa

    2015-04-09

    Aerobic granule, a form of microbial aggregate, exhibits good potential in degrading toxic and recalcitrant substances. In this study, the inhibitory and toxic effects of trichloroethylene (TCE), a model compound for aerobic co-metabolism, on phenol-grown aerobic granules were systematically studied, using respiratory activities after exposure to TCE as indicators. High TCE concentration did not exert positive or negative effects on the subsequent endogenous respiration rate or phenol dependent specific oxygen utilization rate (SOUR), indicating the absence of solvent stress and induction effect on phenol-hydroxylase. Phenol-grown aerobic granules exhibited a unique response to TCE transformation product toxicity, that small amount of TCE transformation enhanced the subsequent phenol SOUR. Granules that had transformed between 1.3 and 3.7 mg TCE gSS(-1) showed at most 53% increase in the subsequent phenol SOUR, and only when the transformation exceeded 6.6 mg TCE gSS(-1) did the SOUR dropped below that of the control. This enhancing effect was found to sustain throughout several phenol dosages, and TCE transformation below the toxicity threshold also lessened the granules' sensitivity to higher phenol concentration. The unique toxic effect was possibly caused by the granule's compact structure as a protection barrier against the diffusive transformation product(s) of TCE co-metabolism.

  4. Correlation between Phylogroups and Intracellular Proteomes of Propionibacterium acnes and Differences in the Protein Expression Profiles between Anaerobically and Aerobically Grown Cells

    PubMed Central

    Dekio, Itaru; Culak, Renata; Ball, Graham; Gharbia, Saheer; Shah, Haroun N.

    2013-01-01

    Propionibacterium acnes is one of the dominant commensals on the human skin and also an opportunistic pathogen in relation to acne, sarcoidosis, prostate cancer, and various infections. Recent investigations using housekeeping and virulence genes have revealed that the species consists of three major evolutionary clades (types I, II, and III). In order to investigate protein expression differences between these phylogroups, proteomic profiles of 21 strains of P. acnes were investigated. The proteins extracted from cells cultured under anaerobic and aerobic conditions were analysed using a SELDI-TOF mass spectrometer, high-resolution capillary gel electrophoresis, and LC-MS/ MS. The SELDI spectral profiles were visualised as a heat map and a dendrogram, which resulted in four proteomic groups. Strains belonging to type I were represented in the proteome Group A, while Group B contained type III strains. Groups C and D contained mixtures of types I and II. Each of these groups was not influenced by differences in culture conditions. Under anoxic growth conditions, a type IB strain yielded high expressions of some proteins, such as methylmalonyl-CoA epimerase and the Christie-Atkins-Munch-Petersen (CAMP) factor. The present study revealed good congruence between genomic and proteomic data suggesting that the microenvironment of each subtype may influence protein expression. PMID:23878795

  5. Acclimation of aerobic-activated sludge degrading benzene derivatives and co-metabolic degradation activities of trichloroethylene by benzene derivative-grown aerobic sludge.

    PubMed

    Wang, Shizong; Yang, Qi; Bai, Zhiyong; Wang, Shidong; Wang, Yeyao; Nowak, Karolina M

    2015-01-01

    The acclimation of aerobic-activated sludge for degradation of benzene derivatives was investigated in batch experiments. Phenol, benzoic acid, toluene, aniline and chlorobenzene were concurrently added to five different bioreactors which contained the aerobic-activated sludge. After the acclimation process ended, the acclimated phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic-activated sludge were used to explore the co-metabolic degradation activities of trichloroethylene (TCE). Monod equation was employed to simulate the kinetics of co-metabolic degradation of TCE by benzene derivative-grown sludge. At the end of experiments, the mixed microbial communities grown under different conditions were identified. The results showed that the acclimation periods of microorganisms for different benzene derivatives varied. The maximum degradation rates of TCE for phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic sludge were 0.020, 0.017, 0.016, 0.0089 and 0.0047 mg g SS(-1) h(-1), respectively. The kinetic of TCE degradation in the absence of benzene derivative followed Monod equation well. Also, eight phyla were observed in the acclimated benzene derivative-grown aerobic sludge. Each of benzene derivative-grown aerobic sludge had different microbial community composition. This study can hopefully add new knowledge to the area of TCE co-metabolic by mixed microbial communities, and further the understanding on the function and applicability of aerobic-activated sludge.

  6. Effects of cascaded vgb promoters on poly(hydroxybutyrate) (PHB) synthesis by recombinant Escherichia coli grown micro-aerobically.

    PubMed

    Wu, Hong; Wang, Huan; Chen, Jinchun; Chen, Guo-Qiang

    2014-12-01

    Micro-aeration is a situation that will be encountered in bacterial cell growth especially when the saturated dissolved oxygen level cannot match the demand from cells grown to a high density. Therefore, it is desirable to separate aerobic growth and micro-aerobic product formation into two stages using methods including anaerobic or micro-aerobic promoters that are inducible under low aeration intensity. Eleven potential low aeration-inducible promoters were cloned and studied for their induction strengths under micro-aerobic conditions. Of them, Vitreoscilla hemoglobin promoter (P vgb ) was found to be the strongest among all 11 promoters. At the same time, six E. coli hosts harboring poly(R-3-hydroxybutyrate) (PHB) synthesis operon phaCAB were compared for their ability to accumulate poly(hydroxyalkanoates) (PHA). E. coli S17-1 was demonstrated to be the best host achieving a 70 % (mass fraction) PHB in the cell dry weigh (CDW) after 48 h under micro-aerobic growth. Cascaded P vgb repeats (P nvgb ) were investigated for enhanced expression level under micro-aerobic growth. The highest PHA production was obtained when a promoter containing eight cascaded P vgb repeats (P 8vgb ) was used, 5.37 g/l CDW containing 90 % PHB was obtained from recombinant in E. coli S17-1. Cells grew further to 6.30 g/l CDW containing 91 % PHB when oxygen-responsive transcription factor ArcA (arcA) was deleted in the same recombinant E. coli S17-1. This study revealed that vgb promoter containing cascaded P vgb repeats (P 8vgb ) is useful for product formation under low aeration intensity.

  7. Root morphology, hydraulic conductivity and plant water relations of high-yielding rice grown under aerobic conditions

    PubMed Central

    Kato, Yoichiro; Okami, Midori

    2011-01-01

    Background and Aims Increasing physical water scarcity is a major constraint for irrigated rice (Oryza sativa) production. ‘Aerobic rice culture’ aims to maximize yield per unit water input by growing plants in aerobic soil without flooding or puddling. The objective was to determine (a) the effect of water management on root morphology and hydraulic conductance, and (b) their roles in plant–water relationships and stomatal conductance in aerobic culture. Methods Root system development, stomatal conductance (gs) and leaf water potential (Ψleaf) were monitored in a high-yielding rice cultivar (‘Takanari’) under flooded and aerobic conditions at two soil moisture levels [nearly saturated (> –10 kPa) and mildly dry (> –30 kPa)] over 2 years. In an ancillary pot experiment, whole-plant hydraulic conductivity (soil-leaf hydraulic conductance; Kpa) was measured under flooded and aerobic conditions. Key Results Adventitious root emergence and lateral root proliferation were restricted even under nearly saturated conditions, resulting in a 72–85 % reduction in total root length under aerobic culture conditions. Because of their reduced rooting size, plants grown under aerobic conditions tended to have lower Kpa than plants grown under flooded conditions. Ψleaf was always significantly lower in aerobic culture than in flooded culture, while gs was unchanged when the soil moisture was at around field capacity. gs was inevitably reduced when the soil water potential at 20-cm depth reached –20 kPa. Conclusions Unstable performance of rice in water-saving cultivations is often associated with reduction in Ψleaf. Ψleaf may reduce even if Kpa is not significantly changed, but the lower Ψleaf would certainly occur in case Kpa reduces as a result of lower water-uptake capacity under aerobic conditions. Rice performance in aerobic culture might be improved through genetic manipulation that promotes lateral root branching and rhizogenesis as well as deep

  8. A novel terminal oxidase, cytochrome baa3 purified from aerobically grown Pseudomonas aeruginosa: it shows a clear difference between resting state and pulsed state.

    PubMed

    Fujiwara, T; Fukumori, Y; Yamanaka, T

    1992-08-01

    A novel type of cytochrome c oxidase was purified to homogeneity from Pseudomonas aeruginosa which was grown aerobically. The purified oxidase contained two molecules of heme a, two atoms of copper, and one molecule of protoheme per molecule. One of the two heme a molecules in the oxidase reacted with carbon monoxide, so that the enzyme was of baa3-type. The oxidase molecule was composed of three subunits with molecular weights of 38,000, 57,000, and 82,000. Although the oxidase oxidized ferrocytochrome c-550 obtained from the bacterial cells grown aerobically, the oxidizing activity was not high. The "resting form" and the "pulsed form" of the oxidase were observed clearly with this enzyme, and the transition from the resting form to the pulsed form was accompanied by a distinct change of the enzymatic activity. The difference in the kinetics of the catalytic reactions between the two forms is discussed.

  9. Expression of a functional oxygen-labile nitrogenase component in the mitochondrial matrix of aerobically grown yeast

    PubMed Central

    López-Torrejón, Gema; Jiménez-Vicente, Emilio; Buesa, José María; Hernandez, Jose A.; Verma, Hemant K.; Rubio, Luis M.

    2016-01-01

    The extreme sensitivity of nitrogenase towards oxygen stands as a major barrier to engineer biological nitrogen fixation into cereal crops by direct nif gene transfer. Here, we use yeast as a model of eukaryotic cell and show that aerobically grown cells express active nitrogenase Fe protein when the NifH polypeptide is targeted to the mitochondrial matrix together with the NifM maturase. Co-expression of NifH and NifM with Nif-specific Fe–S cluster biosynthetic proteins NifU and NifS is not required for Fe protein activity, demonstrating NifH ability to incorporate endogenous mitochondrial Fe–S clusters. In contrast, expression of active Fe protein in the cytosol requires both anoxic growth conditions and co-expression of NifH and NifM with NifU and NifS. Our results show the convenience of using mitochondria to host nitrogenase components, thus providing instrumental technology for the grand challenge of engineering N2-fixing cereals. PMID:27126134

  10. Expression of a functional oxygen-labile nitrogenase component in the mitochondrial matrix of aerobically grown yeast.

    PubMed

    López-Torrejón, Gema; Jiménez-Vicente, Emilio; Buesa, José María; Hernandez, Jose A; Verma, Hemant K; Rubio, Luis M

    2016-04-29

    The extreme sensitivity of nitrogenase towards oxygen stands as a major barrier to engineer biological nitrogen fixation into cereal crops by direct nif gene transfer. Here, we use yeast as a model of eukaryotic cell and show that aerobically grown cells express active nitrogenase Fe protein when the NifH polypeptide is targeted to the mitochondrial matrix together with the NifM maturase. Co-expression of NifH and NifM with Nif-specific Fe-S cluster biosynthetic proteins NifU and NifS is not required for Fe protein activity, demonstrating NifH ability to incorporate endogenous mitochondrial Fe-S clusters. In contrast, expression of active Fe protein in the cytosol requires both anoxic growth conditions and co-expression of NifH and NifM with NifU and NifS. Our results show the convenience of using mitochondria to host nitrogenase components, thus providing instrumental technology for the grand challenge of engineering N2-fixing cereals.

  11. Microoxic Niches within the Thylakoid Stroma of Air-Grown Chlamydomonas reinhardtii Protect [FeFe]-Hydrogenase and Support Hydrogen Production under Fully Aerobic Environment1[OPEN

    PubMed Central

    Liran, Oded; Milrad, Yuval; Eilenberg, Haviva; Weiner, Iddo

    2016-01-01

    Photosynthetic hydrogen production in the microalga Chlamydomonas reinhardtii is catalyzed by two [FeFe]-hydrogenase isoforms, HydA1 and HydA2, both irreversibly inactivated upon a few seconds exposure to atmospheric oxygen. Until recently, it was thought that hydrogenase is not active in air-grown microalgal cells. In contrast, we show that the entire pool of cellular [FeFe]-hydrogenase remains active in air-grown cells due to efficient scavenging of oxygen. Using membrane inlet mass spectrometry, 18O2 isotope, and various inhibitors, we were able to dissect the various oxygen uptake mechanisms. We found that both chlororespiration, catalyzed by plastid terminal oxidase, and Mehler reactions, catalyzed by photosystem I and Flavodiiron proteins, significantly contribute to oxygen uptake rate. This rate is considerably enhanced with increasing light, thus forming local anaerobic niches at the proximity of the stromal face of the thylakoid membrane. Furthermore, we found that in transition to high light, the hydrogen production rate is significantly enhanced for a short duration (100 s), thus indicating that [FeFe]-hydrogenase functions as an immediate sink for surplus electrons in aerobic as well as in anaerobic environments. In summary, we show that an anaerobic locality in the chloroplast preserves [FeFe]-hydrogenase activity and supports continuous hydrogen production in air-grown microalgal cells. PMID:27443604

  12. Characterization of an Escherichia coli K12 mutant that is sensitive to chlorate when grown aerobically.

    PubMed Central

    Giordano, G; Grillet, L; Rosset, R; Dou, J H; Azoulay, E; Haddock, B A

    1978-01-01

    Escherichia coli can normally grow aerobically in the presence of chlorate; however, mutants can be isolated that can no longer grow under these conditions. We present here the biochemical characterization of one such mutant and show that the primary genetic lesion occurs in the ubiquinone-8-biosynthetic pathway. As a consequence of this, under aerobic growth conditions the mutant is apparently unable to synthesize formate dehydrogenase, but can synthesize a Benzyl Viologen-dependent nitrate reductase activity. The nature of this activity is discussed. PMID:369552

  13. Teaching Aerobic Cell Respiration Using the 5Es

    ERIC Educational Resources Information Center

    Patro, Edward T.

    2008-01-01

    The 5E teaching model provides a five step method for teaching science. While the sequence of the model is strictly linear, it does provide opportunities for the teacher to "revisit" prior learning before moving on. The 5E method is described as it relates to the teaching of aerobic cell respiration.

  14. Colon tumor cells grown in NASA Bioreactor

    NASA Technical Reports Server (NTRS)

    2001-01-01

    These photos compare the results of colon carcinoma cells grown in a NASA Bioreactor flown on the STS-70 Space Shuttle in 1995 flight and ground control experiments. The cells grown in microgravity (left) have aggregated to form masses that are larger and more similar to tissue found in the body than the cells cultured on the ground (right). The principal investigator is Milburn Jessup of the University of Texas M. D. Anderson Cancer Center. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Cell constructs grown in a rotating bioreactor on Earth (left) eventually become too large to stay suspended in the nutrient media. In the microgravity of orbit, the cells stay suspended. Rotation then is needed for gentle stirring to replenish the media around the cells. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). Credit: NASA and University of Texas M. D. Anderson Cancer Center.

  15. Rate limiting factors in trichloroethylene co-metabolic degradation by phenol-grown aerobic granules.

    PubMed

    Zhang, Yi; Tay, Joo Hwa

    2014-04-01

    The potential of aerobic granular sludge in co-metabolic removal of recalcitrant substances was evaluated using trichloroethylene (TCE) as the model compound. Aerobic granules cultivated in a sequencing batch reactor with phenol as the growth substrate exhibited TCE and phenol degradation activities lower than previously reported values. Depletion of reducing energy and diffusion limitation within the granules were investigated as the possible rate limiting factors. Sodium formate and citrate were supplied to the granules in batch studies as external electron sources. No significant enhancing effect was observed on the instant TCE transformation rates, but 10 mM formate could improve the ultimate transformation capacity by 26 %. Possible diffusion barrier was studied by sieving the biomass into five size fractions, and determining their specific TCE and phenol degradation rates and capacities. Biomass in the larger size fractions generally showed lower activities. Large granules of >700 μm diameter exhibited only 22 % of the flocs' TCE transformation capacity and 35 % of its phenol dependent SOUR, indicating the possible occurrence of diffusion limitation in larger biomass. However, the highest specific TCE transformation rate was observed with the fraction that mostly consisted of small granules (150-300 μm), suggesting an optimal size range while applying aerobic granules in TCE co-metabolic removal.

  16. Microbial fuel cells with highly active aerobic biocathodes

    NASA Astrophysics Data System (ADS)

    Milner, Edward M.; Popescu, Dorin; Curtis, Tom; Head, Ian M.; Scott, Keith; Yu, Eileen H.

    2016-08-01

    Microbial fuel cells (MFCs), which convert organic waste to electricity, could be used to make the wastewater infrastructure more energy efficient and sustainable. However, platinum and other non-platinum chemical catalysts used for the oxygen reduction reaction (ORR) at the cathode of MFCs are unsustainable due to their high cost and long-term degradation. Aerobic biocathodes, which use microorganisms as the biocatalysts for cathode ORR, are a good alternative to chemical catalysts. In the current work, high-performing aerobic biocathodes with an onset potential for the ORR of +0.4 V vs. Ag/AgCl were enriched from activated sludge in electrochemical half-cells poised at -0.1 and + 0.2 V vs. Ag/AgCl. Gammaproteobacteria, distantly related to any known cultivated gammaproteobacterial lineage, were identified as dominant in these working electrode biofilms (23.3-44.3% of reads in 16S rRNA gene Ion Torrent libraries), and were in very low abundance in non-polarised control working electrode biofilms (0.5-0.7%). These Gammaproteobacteria were therefore most likely responsible for the high activity of biologically catalysed ORR. In MFC tests, a high-performing aerobic biocathode increased peak power 9-fold from 7 to 62 μW cm-2 in comparison to an unmodified carbon cathode, which was similar to peak power with a platinum-doped cathode at 70 μW cm-2.

  17. Characterisation of aerobically grown non-spore-forming bacteria from paper mill pulps containing recycled fibres.

    PubMed

    Suihko, Maija-Liisa; Skyttä, Eija

    2009-01-01

    A total of 179 non-spore-forming bacteria aerobically growing on Nutrient Agar, Plate Count Agar or in specific enrichment conditions for salmonella, campylobacteria, listeria, yersinia or staphylococci, were isolated from 16 untreated paper mill pulps. After phenotypical screening the isolates were characterised by automated ribotyping and partial sequencing of the 16S rRNA gene. They could be divided into seven taxonomical classes representing 63 taxa (species): actinobacteria (11 species), bacilli (7), flavobacteria (3) alphaproteobacteria (10), betaproteobacteria (5), gammaproteobacteria (25) and sphingobacteria (2). Most of the gammaproteobacteria were enterobacteria, mainly species of the genera Enterobacter (7 species, 7 samples/3 mills) and Klebsiella (5 species, 6 samples/3 mills). Other commonly occurring bacteria were most closely related to Microbacterium barkeri (7 samples/3 mills), Cloacibacterium normanense (6 samples/2 mills), Pseudoxanthomonas taiwanensis (5 samples/2 mills) and Sphingobacterium composti (5 samples/1 mill). Sporadic isolates of Listeria innocua, L. monocytogenes, Enterococcus casseliflavus and Staphylococcus warneri were detected, from which only L. monocytogenes is considered to be a food pathogen. No isolates of the genera Campylobacter, Salmonella or Yersinia were detected. The detected bacteria may be harmful in process control, but the load of food pathogens with recycled fibres to paper machines is insignificant. Faecal contamination of the pulp samples was not indicated.

  18. Characterization of rice (Oryza sativa L.) genotypes on the basis of morpho-physiological and biochemical traits grown under aerobic situation in rainfed ecosystem .

    PubMed

    Kumar, Santosh; Dwivedi, Sharad Kumar; Singh, S S; Kumar, Sanjeev; Sundaram, R K; Shivani; Mall, A K

    2015-07-01

    The objective of the present study was to examine the effect of aerobic situation on yield, physiological and biochemical traits of advanced breeding lines of rice. Experiment was conducted with two set of rice genotypes under two water regimes (aerobic and irrigated), during three consecutive wet seasons 2010-2012. Significant decrease in yield was observed in rice genotypes grown under aerobic situation as compared to the irrigated ones. Promising rice genotypes having the ability to maintain high plant biomass, harvest index, early vegetative vigour, improved physiological and biochemical traits in terms of relative water content (RWC), leaf area index (LAI), total soluble sugar, starch, protien and proline content help to sustain higher grain yield under aerobic situation. The yield gap between aerobic and irrigated rice ranged between 24% to 68%. Grain yield showed positive correlation with harvest index (0.434), test weight (0.647), plant biomass (0.411) and effective tiller numbers (0.473), whereas spikelet sterility was negative associated (-0.380). The current study suggested that promising genotypes viz., IR77298-14-1-2-130-2, IR84899-B-182-3-1-1-2, IR84887-B-157-38-1-1-3 and IR 84899-B-179-1-1-1-2 for aerobic situation, showing yield advantage due to better performance of physiological and biochemical traits, might be adopted in large area of rainfed ecosystem as well as in irrigated areas where water scarcity was a major problem.

  19. Oleanolic acid suppresses aerobic glycolysis in cancer cells by switching pyruvate kinase type M isoforms.

    PubMed

    Liu, Jia; Wu, Ning; Ma, Leina; Liu, Ming; Liu, Ge; Zhang, Yuyan; Lin, Xiukun

    2014-01-01

    Warburg effect, one of the hallmarks for cancer cells, is characterized by metabolic switch from mitochondrial oxidative phosphorylation to aerobic glycolysis. In recent years, increased expression level of pyruvate kinase M2 (PKM2) has been found to be the culprit of enhanced aerobic glycolysis in cancer cells. However, there is no agent inhibiting aerobic glycolysis by targeting PKM2. In this study, we found that Oleanolic acid (OA) induced a switch from PKM2 to PKM1, and consistently, abrogated Warburg effect in cancer cells. Suppression of aerobic glycolysis by OA is mediated by PKM2/PKM1 switch. Furthermore, mTOR signaling was found to be inactivated in OA-treated cancer cells, and mTOR inhibition is required for the effect of OA on PKM2/PKM1 switch. Decreased expression of c-Myc-dependent hnRNPA1 and hnRNPA1 was responsible for OA-induced switch between PKM isoforms. Collectively, we identified that OA is an antitumor compound that suppresses aerobic glycolysis in cancer cells and there is potential that PKM2 may be developed as an important target in aerobic glycolysis pathway for developing novel anticancer agents.

  20. Oleanolic Acid Suppresses Aerobic Glycolysis in Cancer Cells by Switching Pyruvate Kinase Type M Isoforms

    PubMed Central

    Ma, Leina; Liu, Ming; Liu, Ge; Zhang, Yuyan; Lin, Xiukun

    2014-01-01

    Warburg effect, one of the hallmarks for cancer cells, is characterized by metabolic switch from mitochondrial oxidative phosphorylation to aerobic glycolysis. In recent years, increased expression level of pyruvate kinase M2 (PKM2) has been found to be the culprit of enhanced aerobic glycolysis in cancer cells. However, there is no agent inhibiting aerobic glycolysis by targeting PKM2. In this study, we found that Oleanolic acid (OA) induced a switch from PKM2 to PKM1, and consistently, abrogated Warburg effect in cancer cells. Suppression of aerobic glycolysis by OA is mediated by PKM2/PKM1 switch. Furthermore, mTOR signaling was found to be inactivated in OA-treated cancer cells, and mTOR inhibition is required for the effect of OA on PKM2/PKM1 switch. Decreased expression of c-Myc-dependent hnRNPA1 and hnRNPA1 was responsible for OA-induced switch between PKM isoforms. Collectively, we identified that OA is an antitumor compound that suppresses aerobic glycolysis in cancer cells and there is potential that PKM2 may be developed as an important target in aerobic glycolysis pathway for developing novel anticancer agents. PMID:24626155

  1. Platinum blue staining of cells grown in electrospun scaffolds.

    PubMed

    Yusuf, Mohammed; Millas, Ana Luiza G; Estandarte, Ana Katrina C; Bhella, Gurdeep K; McKean, Robert; Bittencourt, Edison; Robinson, Ian K

    2014-01-01

    Fibroblast cells grown in electrospun polymer scaffolds were stained with platinum blue, a heavy metal stain, and imaged using scanning electron microscopy. Good contrast on the cells was achieved compared with samples that were gold sputter coated. The cell morphology could be clearly observed, and the cells could be distinguished from the scaffold fibers. Here we optimized the required concentration of platinum blue for imaging cells grown in scaffolds and show that a higher concentration causes platinum aggregation. Overall, platinum blue is a useful stain for imaging cells because of its enhanced contrast using scanning electron microscopy (SEM). In the future it would be useful to investigate cell growth and morphology using three-dimensional imaging methods.

  2. Comparative studies of two membrane fractions isolated from chemotrophically and phototrophically grown cells of Rhodopseudomonas capsulata.

    PubMed Central

    Garcia, A F; Drews, G; Reidl, H H

    1981-01-01

    Light and heavy membrane fractions have been isolated by equilibrium sucrose density centrifugation from Rhodopseudomonas capsulata 938 GCM grown aerobically in the dark (chemotrophically) and anaerobically in the light (phototrophically). The densities of the light and heavy fractions from phototrophic cells were 1.1004 to 1.1006 and 1.1478, respectively, and the densities of the light and heavy fractions from chemotrophic cells were 1.0957 to 1.0958 and 1.1315, respectively. Both fractions were active in photochemical and respiratory functions and in electron transport-coupled phosphorylation. The light membrane fraction isolated from chemotrophic cells contained the reaction center and the light-harvesting pigment-protein complex B 870, but not the variable light-harvesting complex B 800-850. A small amount of the complex B 800-850 was present in the light fraction isolated from phototrophically grown cells, but it was not energetically coupled to the photosynthetic apparatus. From inhibitor studies, difference spectroscopy, and measurement of enzyme activities it was tentatively concluded that the light membrane fraction contains only the reduced nicotinamide adenine dinucleotide-oxidizing electron transport chain having a KCN-insensitive, low-potential cytochrome c oxidase, whereas the heavy fraction contains additionally the succinate dehydrogenase and a high-potential cytochrome b terminal oxidase sensitive to KCN. The light membrane fraction was more labile than the heavy fraction in terms of phosphorylating activity. PMID:7204341

  3. Cancer cells recovering from damage exhibit mitochondrial restructuring and increased aerobic glycolysis

    SciTech Connect

    Akakura, Shin; Ostrakhovitch, Elena; Sanokawa-Akakura, Reiko; Tabibzadeh, Siamak

    2014-06-13

    Highlights: • Some cancer cells recover from severe damage that causes cell death in majority of cells. • Damage-Recovered (DR) cancer cells show reduced mitochondria, mDNA and mitochondrial enzymes. • DR cells show increased aerobic glycolysis, ATP, cell proliferation, and resistance to damage. • DR cells recovered from in vivo damage also show increased glycolysis and proliferation rate. - Abstract: Instead of relying on mitochondrial oxidative phosphorylation, most cancer cells rely heavily on aerobic glycolysis, a phenomenon termed as “the Warburg effect”. We considered that this effect is a direct consequence of damage which persists in cancer cells that recover from damage. To this end, we studied glycolysis and rate of cell proliferation in cancer cells that recovered from severe damage. We show that in vitro Damage-Recovered (DR) cells exhibit mitochondrial structural remodeling, display Warburg effect, and show increased in vitro and in vivo proliferation and tolerance to damage. To test whether cancer cells derived from tumor microenvironment can show similar properties, we isolated Damage-Recovered (T{sup DR}) cells from tumors. We demonstrate that T{sup DR} cells also show increased aerobic glycolysis and a high proliferation rate. These findings show that Warburg effect and its consequences are induced in cancer cells that survive severe damage.

  4. Dependence of structure stability and integrity of aerobic granules on ATP and cell communication.

    PubMed

    Jiang, Bo; Liu, Yu

    2013-06-01

    Aerobic granules are dense and compact microbial aggregates with various bacterial species. Recently, aerobic granulation technology has been extensively explored for treatment of municipal and industrial wastewaters. However, little information is currently available with regard to their structure stability and integrity at levels of energy metabolism and cell communication. In the present study, a typical chemical uncoupler, 3,3',4',5-tetrachlorosalicylanilide with the power to dissipate proton motive force and subsequently inhibit adenosine triphosphate (ATP) generation, was used to investigate possible roles of ATP and cell communication in maintaining the structure stability and integrity of aerobic granules. It was found that inhibited ATP synthesis resulted in the reduced production of autoinducer-2 and N-acylhomoserine lactones essential for cell communication, while lowered extracellular polymeric substance (EPS) production was also observed. As a consequence, aerobic granules appeared to break up. This study showed that ATP-dependent quorum sensing and EPS were essential for sustaining the structure stability and integrity of aerobic granules.

  5. Chidamide Inhibits Aerobic Metabolism to Induce Pancreatic Cancer Cell Growth Arrest by Promoting Mcl-1 Degradation

    PubMed Central

    Wang, Yanbing; Kuai, Qiyuan; Li, Changlan; Wang, Yu; Jiang, Xingwei; Wang, Xuanlin; Li, Weijing; He, Min; Ren, Suping; Yu, Qun

    2016-01-01

    Pancreatic cancer is a fatal malignancy worldwide and urgently requires valid therapies. Previous research showed that the HDAC inhibitor chidamide is a promising anti-cancer agent in pancreatic cancer cell lines. In this study, we elucidate a probable underlying anti-cancer mechanism of chidamide involving the degradation of Mcl-1. Mcl-1 is frequently upregulated in human cancers, which has been demonstrated to participate in oxidative phosphorylation, in addition to its anti-apoptotic actions as a Bcl-2 family member. The pancreatic cancer cell lines BxPC-3 and PANC-1 were treated with chidamide, resulting in Mcl-1 degradation accompanied by induction of Mcl-1 ubiquitination. Treatment with MG132, a proteasome inhibitor reduced Mcl-1 degradation stimulated by chidamide. Chidamide decreased O2 consumption and ATP production to inhibit aerobic metabolism in both pancreatic cancer cell lines and primary cells, similar to knockdown of Mcl-1, while overexpression of Mcl-1 in pancreatic cancer cells could restore the aerobic metabolism inhibited by chidamide. Furthermore, chidamide treatment or Mcl-1 knockdown significantly induced cell growth arrest in pancreatic cancer cell lines and primary cells, and Mcl-1 overexpression could reduce this cell growth inhibition. In conclusion, our results suggest that chidamide promotes Mcl-1 degradation through the ubiquitin-proteasome pathway, suppressing the maintenance of mitochondrial aerobic respiration by Mcl-1, and resulting in inhibition of pancreatic cancer cell proliferation. Our work supports the claim that chidamide has therapeutic potential for pancreatic cancer treatment. PMID:27875574

  6. Cell density-correlated induction of pyruvate decarboxylase under aerobic conditions in the yeast Pichia stipitis.

    PubMed

    Mergler, M; Klinner, U

    2001-01-01

    During the aerobic batch cultivation of P. stipitis CBS 5776 with glucose, pyruvate decarboxylase was activated in a cell number-correlated manner. Activation started when a cell number between 7 x 10(7) and x 10(8) cells ml(-1) was reached and the enzyme activity increased during further cultivation. This induction might have been triggered either by an unknown quorum sensing system or by a shortage of cytoplasmic acetyl-CoA.

  7. Vertebrate blood cell volume increases with temperature: implications for aerobic activity

    PubMed Central

    Zenil-Ferguson, Rosana

    2014-01-01

    Aerobic activity levels increase with body temperature across vertebrates. Differences in these levels, from highly active to sedentary, are reflected in their ecology and behavior. Yet, the changes in the cardiovascular system that allow for greater oxygen supply at higher temperatures, and thus greater aerobic activity, remain unclear. Here we show that the total volume of red blood cells in the body increases exponentially with temperature across vertebrates, after controlling for effects of body size and taxonomy. These changes are accompanied by increases in relative heart mass, an indicator of aerobic activity. The results point to one way vertebrates may increase oxygen supply to meet the demands of greater activity at higher temperatures. PMID:24765580

  8. Aerobic Metabolism of Streptococcus agalactiae

    PubMed Central

    Mickelson, M. N.

    1967-01-01

    Streptococcus agalactiae cultures possess an aerobic pathway for glucose oxidation that is strongly inhibited by cyanide. The products of glucose oxidation by aerobically grown cells of S. agalactiae 50 are lactic and acetic acids, acetylmethylcarbinol, and carbon dioxide. Glucose degradation products by aerobically grown cells, as percentage of glucose carbon, were 52 to 61% lactic acid, 20 to 23% acetic acid, 5.5 to 6.5% acetylmethylcarbinol, and 14 to 16% carbon dioxide. There was no evidence for a pentose cycle or a tricarboxylic acid cycle. Crude cell-free extracts of S. agalactiae 50 possessed a strong reduced nicotinamide adenine dinucleotide (NADH2) oxidase that is also cyanide-sensitive. Dialysis or ultrafiltration of the crude, cell-free extract resulted in loss of NADH2 oxidase activity. Oxidase activity was restored to the inactive extract by addition of the ultrafiltrate or by addition of menadione or K3Fe(CN)6. Noncytochrome iron-containing pigments were present in cell-free extracts of S. agalactiae. The possible participation of these pigments in the respiration of S. agalactiae is presently being studied. PMID:4291090

  9. Radiation-induced changes in nucleoid halo diameteres of aerobic and hypoxic SF-126 human brain tumor cells

    SciTech Connect

    Wang, J.; Basu, H.S.; Hu, L.; Feuerstein, B.G.; Deen, D.F.

    1995-02-01

    Nucleoid halo diameters were measured to assay changes in DNA supercoiling in human brain tumor cell line SF-126 after irradiation under aerobic or hypoxic conditions. In unirradiated aerobic cells, a typical propidium iodide titration curve showed that with increasing concentrations of propodium iodide, the halo diameter increased and then decreased with the unwinding and subsequent rewinding of DNA supercoils. In irradiated cells, the rewinding of DNA supercoils was inhibited, resulting in an increased halo diameter, in a radiation dose-dependent manner. To produce equal increases in halo diameter required about a threefold higher radiation dose in hypoxic cells than in aerobic cells. Quantitatively similiar differences in the radiation sensitivities of hypoxic and aerobic cells were demonstrated by a colony-forming efficiency assay. These findings suggest that the nucleoid halo assay may be used as a rapid measure of the inherent radiation sensitivity of human tumors. 22 refs., 5 figs.

  10. Lower white blood cell counts in elite athletes training for highly aerobic sports.

    PubMed

    Horn, P L; Pyne, D B; Hopkins, W G; Barnes, C J

    2010-11-01

    White cell counts at rest might be lower in athletes participating in selected endurance-type sports. Here, we analysed blood tests of elite athletes collected over a 10-year period. Reference ranges were established for 14 female and 14 male sports involving 3,679 samples from 937 females and 4,654 samples from 1,310 males. Total white blood cell counts and counts of neutrophils, lymphocytes and monocytes were quantified. Each sport was scaled (1-5) for its perceived metabolic stress (aerobic-anaerobic) and mechanical stress (concentric-eccentric) by 13 sports physiologists. Substantially lower total white cell and neutrophil counts were observed in aerobic sports of cycling and triathlon (~16% of test results below the normal reference range) compared with team or skill-based sports such as water polo, cricket and volleyball. Mechanical stress of sports had less effect on the distribution of cell counts. The lower white cell counts in athletes in aerobic sports probably represent an adaptive response, not underlying pathology.

  11. Exosomes from human mesenchymal stem cells conduct aerobic metabolism in term and preterm newborn infants.

    PubMed

    Panfoli, Isabella; Ravera, Silvia; Podestà, Marina; Cossu, Claudia; Santucci, Laura; Bartolucci, Martina; Bruschi, Maurizio; Calzia, Daniela; Sabatini, Federica; Bruschettini, Matteo; Ramenghi, Luca Antonio; Romantsik, Olga; Marimpietri, Danilo; Pistoia, Vito; Ghiggeri, Gianmarco; Frassoni, Francesco; Candiano, Giovanni

    2016-04-01

    Exosomes are secreted nanovesicles that are able to transfer RNA and proteins to target cells. The emerging role of mesenchymal stem cell (MSC) exosomes as promoters of aerobic ATP synthesis restoration in damaged cells, prompted us to assess whether they contain an extramitochondrial aerobic respiration capacity. Exosomes were isolated from culture medium of human MSCs from umbilical cord of ≥37-wk-old newborns or between 28- to 30-wk-old newborns (i.e.,term or preterm infants). Characterization of samples was conducted by cytofluorometry. Oxidative phosphorylation capacity was assessed by Western blot analysis, oximetry, and luminometric and fluorometric analyses. MSC exosomes express functional respiratory complexes I, IV, and V, consuming oxygen. ATP synthesis was only detectable in exosomes from term newborns, suggestive of a specific mechanism that is not completed at an early gestational age. Activities are outward facing and comparable to those detected in mitochondria isolated from term MSCs. MSC exosomes display an unsuspected aerobic respiratory ability independent of whole mitochondria. This may be relevant for their ability to rescue cell bioenergetics. The differential oxidative metabolism of pretermvs.term exosomes sheds new light on the preterm newborn's clinical vulnerability. A reduced ability to repair damaged tissue and an increased capability to cope with anoxic environment for preterm infants can be envisaged.-Panfoli, I., Ravera, S., Podestà, M., Cossu, C., Santucci, L., Bartolucci, M., Bruschi, M., Calzia, D., Sabatini, F., Bruschettini, M., Ramenghi, L. A., Romantsik, O., Marimpietri, D., Pistoia, V., Ghiggeri, G., Frassoni, F., Candiano, G. Exosomes from human mesenchymal stem cells conduct aerobic metabolism in term and preterm newborn infants.

  12. Gene expression in Fusarium graminearum grown on plant cell wall.

    PubMed

    Carapito, Raphaël; Hatsch, Didier; Vorwerk, Sonja; Petkovski, Elizabet; Jeltsch, Jean-Marc; Phalip, Vincent

    2008-05-01

    Fusarium graminearum is a phytopathogenic filamentous fungus attacking a wide range of plants including Humulus lupulus (hop). Transcriptional analysis of F. graminearum grown on minimal media containing hop cell wall or glucose as the sole carbon source was performed by applying a highly stringent method combining microarrays and a subtracted cDNA library. In addition to genes coding for various cell wall degrading enzymes (CWDE), several metabolic pathways were induced in response to the plant cell wall substrate. Many genes participating in these pathways are probably involved in cellular transport. But the most interesting was that all the genes composing the 4-aminobutyrate-shunt (GABA-shunt) were also up-regulated in the presence of plant cell wall material and were present in the cDNA library. This study provides a description of a part of the fungal gene expression profile when it is in contact with raw biological materials, and helps in understanding the plant cell wall degradation and the infection process.

  13. Physiological and functional diversity of phenol degraders isolated from phenol-grown aerobic granules: Phenol degradation kinetics and trichloroethylene co-metabolic activities.

    PubMed

    Zhang, Yi; Tay, Joo Hwa

    2016-03-15

    Aerobic granule is a novel form of microbial aggregate capable of degrading toxic and recalcitrant substances. Aerobic granules have been formed on phenol as the growth substrate, and used to co-metabolically degrade trichloroethylene (TCE), a synthetic solvent not supporting aerobic microbial growth. Granule formation process, rate limiting factors and the comprehensive toxic effects of phenol and TCE had been systematically studied. To further explore their potential at the level of microbial population and functions, phenol degraders were isolated and purified from mature granules in this study. Phenol and TCE degradation kinetics of 15 strains were determined, together with their TCE transformation capacities and other physiological characteristics. Isolation in the presence of phenol and TCE exerted stress on microbial populations, but the procedure was able to preserve their diversity. Wide variation was found with the isolates' kinetic behaviors, with the parameters often spanning 3 orders of magnitude. Haldane kinetics described phenol degradation well, and the isolates exhibited actual maximum phenol-dependent oxygen utilization rates of 9-449 mg DO g DW(-1) h(-1), in phenol concentration range of 4.8-406 mg L(-1). Both Michaelis-Menten and Haldane types were observed for TCE transformation, with the actual maximum rate of 1.04-21.1 mg TCE g DW(-1) h(-1) occurring between TCE concentrations of 0.42-4.90 mg L(-1). The TCE transformation capacities and growth yields on phenol ranged from 20-115 mg TCE g DW(-1) and 0.46-1.22 g DW g phenol(-1), respectively, resulting in TCE transformation yields of 10-70 mg TCE g phenol(-1). Contact angles of the isolates were between 34° and 82°, suggesting both hydrophobic and hydrophilic cell surface. The diversity in the isolates is a great advantage, as it enables granules to be versatile and adaptive under different operational conditions.

  14. Aerobic expression of Vitreoscilla hemoglobin improves the growth performance of CHO-K1 cells.

    PubMed

    Juárez, Mariana; González-De la Rosa, Claudia H; Memún, Elisa; Sigala, Juan-Carlos; Lara, Alvaro R

    2017-03-01

    Inefficient carbon metabolism is a relevant issue during the culture of mammalian cells for the production of biopharmaceuticals. Therefore, cell engineering strategies to improve the metabolic and growth performance of cell lines are needed. The expression of Vitreoscilla stercoraria hemoglobin (VHb) has been shown to significantly reduce overflow metabolism and improve the aerobic growth of bacteria. However, the effects of VHb on mammalian cells have been rarely studied. Here, the impact of VHb on growth and lactate accumulation during CHO-K1 cell culture was investigated. For this purpose, CHO-K1 cells were transfected with plasmids carrying the vgb or gfp gene to express VHb or green fluorescence protein (GFP), respectively. VHb expression increased the specific growth rate and biomass yields on glucose and glutamine by 60 %, and reduced the amount of lactate produced per cell by 40 %, compared to the GFP-expression controls. Immunofluorescence microscopy showed that VHb is distributed in the cytoplasm and organelles, which support the hypothesis that VHb could serve as an oxygen carrier, enhancing aerobic respiration. These results are useful for the development of better producing cell lines for industrial applications.

  15. Costimulation endows immunotherapeutic CD8 T cells with IL-36-responsiveness during aerobic glycolysis

    PubMed Central

    Tsurutani, Naomi; Mittal, Payal; St Rose, Marie-Clare; Ngoi, Soo Mun; Svedova, Julia; Treadway, Forrest B.; Laubenbacher, Reinhard; Suárez-Ramírez, Jenny E.; Cauley, Linda S.; Adler, Adam J.; Vella, Anthony T.

    2015-01-01

    CD134 and CD137 primed CD8 T cells mount powerful effector responses upon recall, but even without recall these dual costimulated T cells respond to signal 3 cytokines like IL-12. We searched for alternative signal 3 receptor pathways and found the IL-1 family member IL-36R. While IL-36 alone did not stimulate effector CD8 T cells, in combination with IL-12, or more surprisingly IL-2, induced striking and rapid TCR-independent IFN-γ synthesis. To understand how signal 3 responses functioned in dual costimulated T cells we showed that IL-2 induced IL-36R gene expression in a JAK/STAT dependent manner. These data help delineate a sequential stimulation process where IL-2 conditioning must precede IL-36 for IFN-γ synthesis. Importantly, this responsive state was transient, and functioned only in effector T cells capable of aerobic glycolysis. Specifically, as the effector T cells metabolized glucose and consumed O2, they also retained potential to respond through IL-36R. This suggests that T cells use innate receptor pathways like the IL-36R-axis when programmed for aerobic glycolysis. To explore a function for IL-36R in vivo we showed that dual costimulation therapy reduced B16 melanoma tumor growth while increasing IL-36R gene expression. In sum, cytokine therapy to eliminate tumors may target effector T cells, even outside of TCR specificity, as long as the effectors are in the correct metabolic state. PMID:26573834

  16. Human respiratory syncytial virus Memphis 37 grown in HEp-2 cells causes more severe disease in lambs than virus grown in Vero cells.

    PubMed

    Derscheid, Rachel J; van Geelen, Albert; McGill, Jodi L; Gallup, Jack M; Cihlar, Tomas; Sacco, Randy E; Ackermann, Mark R

    2013-11-22

    Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis in infants and young children. A small percentage of these individuals develop severe and even fatal disease. To better understand the pathogenesis of severe disease and develop therapies unique to the less-developed infant immune system, a model of infant disease is needed. The neonatal lamb pulmonary development and physiology is similar to that of infants, and sheep are susceptible to ovine, bovine, or human strains of RSV. RSV grown in Vero (African green monkey) cells has a truncated attachment G glycoprotein as compared to that grown in HEp-2 cells. We hypothesized that the virus grown in HEp-2 cells would cause more severe clinical symptoms and cause more severe pathology. To confirm the hypothesis, lambs were inoculated simultaneously by two different delivery methods (intranasal and nebulized inoculation) with either Vero-grown or HEp-2-grown RSV Memphis 37 (M37) strain of virus to compare viral infection and disease symptoms. Lambs infected with HEp-2 cell-derived virus by either intranasal or nebulization inoculation had significantly higher levels of viral RNA in lungs as well as greater clinical disease including both gross and histopathologic lesions compared to lambs similarly inoculated with Vero-grown virus. Thus, our results provide convincing in vivo evidence for differences in viral infectivity that corroborate previous in vitro mechanistic studies demonstrating differences in the G glycoprotein expression by RSV grown in Vero cells.

  17. Cyctotoxicities of mitomycin C and x rays to aerobic and hypoxic cells in vitro

    SciTech Connect

    Rockwell, S.

    1982-01-01

    Aerobic and hypoxic EMT6 mouse mammary tumor cells in exponential growth in vitro were used to study cell survival after treatment with radiation (250k V X rays) and mitomycin C in various combinations. The cytotoxicities of the two agents were found to be additive as judged by comparing dose-response curves for each agent alone with survival curves after combination therapy and by isobologram analysis. The cytotoxicities resulting from combination treatments were found to be independent of the sequence of the treatments or the interval between treatments.

  18. Azo dye treatment with simultaneous electricity production in an anaerobic-aerobic sequential reactor and microbial fuel cell coupled system.

    PubMed

    Li, Zhongjian; Zhang, Xingwang; Lin, Jun; Han, Song; Lei, Lecheng

    2010-06-01

    A microbial fuel cell and anaerobic-aerobic sequential reactor coupled system was used for azo dye degradation with simultaneous electricity production. Electricity was produced during the co-metabolism process of glucose and azo dye. A microorganism cultured graphite-granular cathode effectively decreased the charge transfer resistance of the cathode and yielded higher power density. Operation parameters including glucose concentration and hydraulic retention time were optimized. The results indicated that recovering electricity during a sequential aerobic-anaerobic azo dye treatment process enhanced chemical oxygen demand removal and did not decrease azo dye removal. Moreover, UV-vis spectra and GC-MS illustrated that the azo bond was cleaved biologically in the anaerobic chamber and abiotically in the aerobic chamber. The toxic intermediates, aromatic amines, were removed by aerobic treatment. Our work demonstrated that the microbial fuel cell and sequential anode-cathode reactor coupled system could be applied to achieve electricity production with simultaneous azo dye degradation.

  19. Aerobic degradation of BDE-209 by Enterococcus casseliflavus: Isolation, identification and cell changes during degradation process.

    PubMed

    Tang, Shaoyu; Yin, Hua; Chen, Shuona; Peng, Hui; Chang, Jingjing; Liu, Zehua; Dang, Zhi

    2016-05-05

    Decabromodiphenyl ether (BDE-209) is one of the most commonly used brominated flame retardants that have contaminated the environment worldwide. Microbial bioremediation has been considered as an effective technique to remove these sorts of persistent organic pollutants. Enterococcus casseliflavus, a gram-positive bacterium capable of aerobically transforming BDE-209, was isolated by our team from sediments in Guiyu, an e-waste dismantling area in Guangdong Province, China. To promote microbial bioremediation of BDE-209 and elucidate the mechanism behind its aerobic degradation, the effects of BDE-209 on the cell changes of E. casseliflavus were examined in this study. The experimental results demonstrated that the high cell surface hydrophobicity (CSH) of E. casseliflavus made the bacteria absorb hydrophobic BDE-209 more easily. E. casseliflavus responded to BDE-209 stress, resulting in an increase in cell membrane permeability and accumulation of BDE-209 inside the cell. The differential expression of intracellular protein was analyzed through two-dimensional gel electrophoresis (2-DE). More than 50 differentially expressed protein spots were reproducibly detected, including 25 up, and 25 down regulated after a 4 days exposure. Moreover, the apoptotic-like cell changes were observed during E. casseliflavus mediated degradation of BDE-209 by means of flow cytometry.

  20. Organic solar cells using CVD-grown graphene electrodes

    NASA Astrophysics Data System (ADS)

    Kim, Hobeom; Bae, Sang-Hoon; Han, Tae-Hee; Lim, Kyung-Geun; Ahn, Jong-Hyun; Lee, Tae-Woo

    2014-01-01

    We report on the development of flexible organic solar cells (OSCs) incorporating graphene sheets synthesized by chemical vapor deposition (CVD) as transparent conducting electrodes on polyethylene terephthalate (PET) substrates. A key barrier that must be overcome for the successful fabrication of OSCs with graphene electrodes is the poor-film properties of water-based poly(3,4-ethylenedioxythiphene):poly(styrenesulfonate) (PEDOT:PSS) when coated onto hydrophobic graphene surfaces. To form a uniform PEDOT:PSS film on a graphene surface, we added perfluorinated ionomers (PFI) to pristine PEDOT:PSS to create ‘GraHEL’, which we then successfully spin coated onto the graphene surface. We systematically investigated the effect of number of layers in layer-by-layer stacked graphene anode of an OSC on the performance parameters including the open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF). As the number of graphene layers increased, the FF tended to increase owing to lower sheet resistance, while Jsc tended to decrease owing to the lower light absorption. In light of this trade-off between sheet resistance and transmittance, we determined that three-layer graphene (3LG) represents the best configuration for obtaining the optimal power conversion efficiency (PCE) in OSC anodes, even at suboptimal sheet resistances. We finally developed efficient, flexible OSCs with a PCE of 4.33%, which is the highest efficiency attained so far by an OSC with CVD-grown graphene electrodes to the best of our knowledge.

  1. Culturing aerobic and anaerobic bacteria and mammalian cells with a microfluidic differential oxygenator.

    PubMed

    Lam, Raymond H W; Kim, Min-Cheol; Thorsen, Todd

    2009-07-15

    In this manuscript, we report on the culture of anaerobic and aerobic species within a disposable multilayer polydimethylsiloxane (PDMS) microfluidic device with an integrated differential oxygenator. A gas-filled microchannel network functioning as an oxygen-nitrogen mixer generates differential oxygen concentration. By controlling the relative flow rate of the oxygen and nitrogen input gases, the dissolved oxygen (DO) concentration in proximal microchannels filled with culture media are precisely regulated by molecular diffusion. Sensors consisting of an oxygen-sensitive dye embedded in the fluid channels permit dynamic fluorescence-based monitoring of the DO concentration using low-cost light-emitting diodes. To demonstrate the general utility of the platform for both aerobic and anaerobic culture, three bacteria with differential oxygen requirements (E. coli, A. viscosus, and F. nucleatum), as well as a model mammalian cell line (murine embryonic fibroblast cells (3T3)), were cultured. Growth characteristics of the selected species were analyzed as a function of eight discrete DO concentrations, ranging from 0 ppm (anaerobic) to 42 ppm (fully saturated).

  2. Recalcitrant organic matter removal from textile wastewater by an aerobic cell-immobilized pellet column.

    PubMed

    Kim, Moonil; Han, Dukkyu; Cui, Fenghao; Bae, Wookeun

    2013-01-01

    The treatment of textile wastewater is difficult because of its recalcitrant organic content. The biological removal of recalcitrant organics requires a long retention time for microbial growth. Activated sludge was immobilized in a polyethylene glycol pellet to allow for sufficient sludge retention time. The pellets were filled in an aerobic cell-immobilized pellet column (CIPC) reactor in order to investigate the removal of recalcitrant organics from textile wastewater. A textile wastewater effluent treated by a conventional activated sludge reactor was used as a target wastewater. The chemical oxygen demand (COD) removal efficiency of the aerobic CIPC reactor at various empty bed contact times was in the range of 42.2-60.5%. Half of the input COD was removed in the lower part (bottom 25% of the reactor volume) of the reactor when the organic loading rate was less than 1.5 kg COD/(m(3)•d). About 15-30% of the input COD was removed in the remaining part of the column reactor. The COD removed in this region was limitedly biodegradable. The biodegradation of recalcitrant organics could be carried out by the interactional functions of the various bacteria consortia by using a cell-immobilization process. The CIPC process could effectively treat textile wastewater using a short retention time because the microorganisms that degrade limitedly biodegradable organics were dominant in the reactor.

  3. SILENCING GASTRIN-RELEASING PEPTIDE RECEPTOR SUPPRESSES KEY REGULATORS OF AEROBIC GLYCOLYSIS IN NEUROBLASTOMA CELLS

    PubMed Central

    Rellinger, Eric J.; Romain, Carmelle; Choi, SunPhil; Qiao, Jingbo; Chung, Dai H.

    2015-01-01

    Background Under normoxic conditions, cancer cells use aerobic glycolysis as opposed to glucose oxidation for energy production; this altered metabolism correlates with poor outcomes in neuroblastoma. Hypoxia-inducible factor-1α (HIF-1α) and pyruvate dehydrogenase kinase 4 (PDK4) regulate aerobic glycolysis, while pyruvate dehydrogenase phosphatase 2 (PDP2) promotes glucose oxidation. Here, we sought to determine whether gastrin-releasing peptide receptor (GRP-R) signaling regulates glucose metabolism. Procedure Neuroblastoma cell lines, BE(2)-C and SK-N-AS, were used. PCR microararay for glucose metabolism was performed on GRP-R silenced cells. Target protein expression was validated using Western blotting and VEGF ELISA. Cobalt chloride (CoCl2) was used to induce chemical hypoxia. Efficacy of targeting PDK regulation in neuroblastoma was assessed using dichloroacetate (DCA) by conducting cell viability assays and Western blotting for apoptotic markers. Results Silencing GRP-R decreased HIF-1α expression and blocked VEGF expression and secretion in both normoxic and CoCl2 induced hypoxia. PCR array analysis identified that GRP-R silencing reduced PDK4 and increased PDP2 mRNA expression. These findings were validated by Western blotting. CoCl2 induced hypoxia increased VEGF secretion, HIF-1α, and PDK4 expression. PDK4 silencing decreased HIF-1α expression and VEGF expression and secretion. DCA treatment decreased BE(2)-C and SK-N-AS proliferation while promoting cell death. GRP-R silencing and DCA treatment synergistically halted BE(2)-C proliferation. Conclusions We report that GRP-R regulates glucose metabolism in neuroblastoma by modulating HIF-1α, PDK4 and PDP2. PDK4 regulates glucose metabolism, in part, via regulation of HIF-1α. Synergistic consequences of GRP-R inhibition and DCA treatment may suggest a novel therapeutic strategy for the treatment of aggressive neuroblastoma. PMID:25630799

  4. Aerobic granular sludge inoculated microbial fuel cells for enhanced epoxy reactive diluent wastewater treatment.

    PubMed

    Cheng, Kai; Hu, Jingping; Hou, Huijie; Liu, Bingchuan; Chen, Qin; Pan, Keliang; Pu, Wenhong; Yang, Jiakuan; Wu, Xu; Yang, Changzhu

    2017-04-01

    Microbial consortiums aggregated on the anode surface of microbial fuel cells (MFCs) are critical factors for electricity generation as well as biodegradation efficiencies of organic compounds. Here in this study, aerobic granular sludge (AGS) was assembled on the surface of the MFC anode to form an AGS-MFC system with superior performance on epoxy reactive diluent (ERD) wastewater treatment. AGS-MFCs successfully shortened the startup time from 13d to 7d compared to the ones inoculated with domestic wastewater. Enhanced toxicity tolerance as well as higher COD removal (77.8% vs. 63.6%) were achieved. The higher ERD wastewater treatment efficiency of AGS-MFC is possibly attributed to the diverse microbial population on MFC biofilm, as well as the synergic degradation of contaminants by both the MFC anode biofilm and AGS granules.

  5. Intracytoplasmic membrane, phospholipid, and sterol content of Methylobacterium organophilum cells grown under different conditions.

    PubMed Central

    Patt, T E; Hanson, R S

    1978-01-01

    Intracytoplasmic membranes were present in Methylobacterium organophilum when cells were grown with methane, but not methanol or glucose, as the sole carbon and energy source. Cells grown with methane as the carbon and energy source and low levels of dissolved oxygen had the greatest amount of intracytoplasmic membrane. Cells grown with increased levels of dissolved oxygen had less intracytoplasmic membrane. The amount of total lipid correlated with the amount of membrane material observed in thin sections. The individual phospholipids varied in amount, but the same four were present in M. organophilum grown with different substrates and oxygen levels. Phosphatidyl choline was present as a major component of the phospholipids. Sterols were present, and they differed from those in the type I methylotroph Methylococcus capsulatus. The relative amounts of different sterols and squalene changed with the substrate provided for growth. The greatest amounts of sterols were found in methane-grown cells grown at low levels of dissolved oxygen. None of the unusual or usual membrane components assayed was uniquely present in the intracytoplasmic membranes. Images PMID:96093

  6. Satellite cell activation induced by aerobic muscle adaptation in response to endurance exercise in humans and rodents.

    PubMed

    Abreu, Phablo; Mendes, Sávio Victor Diógenes; Ceccatto, Vânia Marilande; Hirabara, Sandro Massao

    2017-02-01

    Although the requirement of satellite cells activation and expansion following injury, mechanical load or growth stimulus provoked by resistance exercise has been well established, their function in response to aerobic exercise adaptation remains unclear. A clear relationship between satellite cell expansion in fiber-type specific myosin heavy chain and aerobic performance has been related, independent of myonuclear accretion or muscle growth. However, the trigger for this activation process is not fully understood yet and it seems to be a multi-faceted and well-orchestrated process. Emerging in vitro studies suggest a role for metabolic pathways and oxygen availability for satellite cell activation, modulating the self-renewal potential and cell fate control. The goal of this review is to describe and discuss the current knowledge about the satellite cell activation and expansion in response to aerobic exercise adaptation in human and rodent models. Additionally, findings about the in vitro metabolic control, which seems be involved in the satellite cell activation and cell fate control, are presented and discussed.

  7. A novel biosensor for p-nitrophenol based on an aerobic anode microbial fuel cell.

    PubMed

    Chen, Zhengjun; Niu, Yongyan; Zhao, Shuai; Khan, Aman; Ling, Zhenmin; Chen, Yong; Liu, Pu; Li, Xiangkai

    2016-11-15

    P-nitrophenol is one of the most common contaminants in chemical industrial wastewater, and in situ real-time monitoring of PNP cannot be achieved by conventional analytical techniques. Here, a two-chamber microbial fuel cell with an aerobic anode chamber was tested as a biosensor for in situ real-time monitoring of PNP. Pseudomonas monteilii LZU-3, which was used as the biological recognition element, can form a biofilm on the anode electrode using PNP as a sole substrate. The optimal operation parameters of the biosensor were as follows: external resistance 1000Ω, pH 7.8, temperature 30°C, and maximum PNP concentration 50mgL(-1). Under these conditions, the maximum voltages showed a linear relationship with PNP concentrations ranging from 15±5 to 44±4.5mgL(-1). Furthermore, we developed a novel portable device for in situ real-time monitoring of PNP. When the device was applied to measure PNP in wastewater containing various additional aromatic compounds and metal ions, the performance of the biosensor was not affected and the correlation between the maximum voltages and the PNP concentrations ranging from 9±4mgL(-1) to 36 ± 5mgL(-1) was conserved. The results demonstrated that the MFC biosensor provides a rapid and cost-efficient analytical method for real-time monitoring of toxic and recalcitrant pollutants in environmental samples.

  8. Microbial Cells and Aerobic Respiration from Seafloor to Basement in the South Pacific Gyre

    NASA Astrophysics Data System (ADS)

    D'Hondt, S.; Inagaki, F.; Alvarez Zarikian, C. A.; Morono, Y.; Pockalny, R. A.; Sauvage, J.; Spivack, A. J.

    2014-12-01

    The seafloor is broadly divided into two regions (Emerson et al., 1985): one where sedimentary microbial respiration is high and oxygen (O2) penetrates only millimeters to centimeters into the sediment (Revsbech et al., 1980), and another where sedimentary respiration is low and O2 penetrates much deeper (Murray& Grundmanis, 1980; D'Hondt et al., 2011; Røy et al, 2012; Orcutt et al., 2013). Active anaerobic microbial communities persist for hundreds of meters or more in subseafloor sediment of the high-respiration region. In the low-respiration region, the existence of microbial communities is previously unknown throughout most of the sedimentary sequence (Morita & Zobell, 1955; D'Hondt et al., 2009; Røy et al., 2012). Here we show that microbial cells and aerobic respiration persist through the entire sediment sequence (to depths of at least 75 m below seafloor) throughout the vast expanse of the oligotrophic South Pacific Gyre. This sediment and underlying basalt may be continuously exposed to O2 for its entire history (up to 120 myrs at our sites). Redfield stoichiometry of dissolved O2 and nitrate indicates that net sedimentary O2 reduction is coupled to oxidation of marine organic matter. Oxygen and aerobic communities may occur throughout the entire sediment sequence in 15-44% of the Pacific and 9-37% of the global ocean. This result has major implications for the nature and distribution of subseafloor life. It may ultimately affect the chemical evolution of Earth's mantle and subduction-related volcanic systems. References D'Hondt, S., et al., 2009. Proc. Nat. Acad. Sci. U.S.A. 106, 11651-11656, doi:10.1073/pnas.0811793106. D'Hondt, S., et al., 2011. Proc. IODP 329, doi:10.2204/ iodp.proc.329.2011. Emerson, S., et al., 1985. Deep-Sea Research 32, 1-21. Morita, R.Y. & Zobell, C.E., 1955. Deep-Sea Research 3, 66-73.Murray, J.W. & Grundmanis, V., 1980. Science 209, 1527-1530. Orcutt, B.N., et al., 2013. Nature Communications 4, 2539, DOI: 10.1038/ncomms3539

  9. Immunolabeling of cells grown attached to a substratum or in suspension with actin antibodies.

    PubMed

    Spudich, Anna

    2011-09-01

    Actin is a major component of all eukaryotic cells and is highly conserved across species. The different isoforms of actin show a very high degree of homology, and almost all actins bind cytochalasins, phallotoxins, and DNase I. Actin is important for maintaining cell shape and for myosin-based movements in cells. In addition, the actin cytoskeleton is involved in localization of other molecules in the cytoplasm and in cellular compartmentalization. Polyclonal and monoclonal antibodies with different specificities are commercially available for labeling actin-containing structures in cells. This article describes a protocol for immunolabeling actin that works well for cells grown in tissue culture as monolayers and for cells grown in suspension cultures that can be attached to polylysine-coated coverslips.

  10. Prodigiosin Induces Autolysins in Actively Grown Bacillus subtilis Cells

    PubMed Central

    Danevčič, Tjaša; Borić Vezjak, Maja; Tabor, Maja; Zorec, Maša; Stopar, David

    2016-01-01

    Prodigiosin produced by marine bacterium Vibrio ruber DSM 14379 exhibits a potent antimicrobial activity against a broad range of Gram positive and Gram negative bacteria. The mechanism of prodigiosin antimicrobial action, however, is not known. In this work, the effect of prodigiosin on Bacillus subtilis growth, cell membrane leakage, and induction of autolysins was studied. Treating B. subtilis with prodigiosin resulted in rapid decline of optical density and increased cell membrane leakage measured by β-galactosidase activity. Cell lysis was initiated immediately after treatment with prodigiosin in the middle exponential phase and was completed within 2 h. Lytic activity of prodigiosin in mutant strains with impaired autolysin genes lytABCD decreased for 80% compared to the wild type strain, while in lytABCDEF mutant strain prodigiosin had no bacteriolytic but only bacteriostatic effect. Fast prodigiosin lytic activity on individual B. subtilis cells was confirmed by a modified comet assay. The results indicate that prodigiosin autolysin induction in B. subtilis is growth phase dependent. PMID:26858704

  11. Transcript profiles in cortical cells of maize primary root during ethylene-induced lysigenous aerenchyma formation under aerobic conditions

    PubMed Central

    Takahashi, Hirokazu; Yamauchi, Takaki; Rajhi, Imene; Nishizawa, Naoko K.; Nakazono, Mikio

    2015-01-01

    Background and Aims Internal aeration is important for plants to survive during periods of waterlogging, and the ability to form aerenchyma contributes by creating a continuous gas space between the shoots and the roots. Roots of maize (Zea mays) react to prolonged waterlogging by forming aerenchyma in root cortical cells by programmed cell death (PCD) in response to ethylene. The aim of this study was to understand the molecular mechanisms of ethylene-induced aerenchyma formation by identifying genes that are either up- or downregulated by ethylene treatment in maize root cortical cells. Methods Three-day-old maize seedlings were treated with ethylene for several hours under aerobic conditions. Cortical cells were isolated from the primary roots using laser microdissection (LM), and transcript profiles with and without ethylene treatment were compared by microarray. In addition, the effect on ethylene-induced aerenchyma formation of diphenyleneiodonium (DPI), an inhibitor of NADPH oxidases, was examined in order to assess the involvement of reactive oxygen species (ROS). Key Results A total of 223 genes were identified whose transcript levels were significantly increased or decreased by ethylene treatment in root cortical cells under aerobic conditions. Subsequent tissue-specific quantitative reverse-transcription PCR analyses revealed that ethylene increased the transcript levels of genes related to ethylene signalling in all of the root tissues examined (stelar cells, cortical cells and outer cell layers), whereas it increased the transcript levels of genes related to cell wall modification and proteolysis specifically in the cortical cells. DPI treatment inhibited the ethylene-induced aerenchyma formation and suppressed expression of some cell wall modification-related genes. Conclusions Several genes related to cell wall modification and proteolysis are specifically up- or downregulated in cortical cells during lysigenous aerenchyma formation under aerobic

  12. Plastid distribution in columella cells of a starchless Arabidopsis mutant grown in microgravity

    NASA Technical Reports Server (NTRS)

    Hilaire, E.; Paulsen, A. Q.; Brown, C. S.; Guikema, J. A.; Spooner, B. S. (Principal Investigator)

    1997-01-01

    Wild-type and starchless Arabidopsis thaliana mutant seedlings (TC7) were grown and fixed in the microgravity environment of a U.S. Space Shuttle spaceflight. Computer image analysis of longitudinal sections from columella cells suggest a different plastid positioning mechanism for mutant and wild-type in the absence of gravity.

  13. Improved electroporation efficiency of intact Lactococcus lactis subsp. lactis cells grown in defined media.

    PubMed Central

    McIntyre, D A; Harlander, S K

    1989-01-01

    The impact of growth conditions on electroporation of Lactococcus lactis subsp. lactis LM0230 (previously designated Streptococcus lactis LM0230) was evaluated. Cells grown in M17 broth supplemented with 0.5% glucose (M17-Glu) and two chemically defined synthetic media, FMC and RPMI 1640, all supplemented with 0.24% DL-threonine or 0.5% glycine, were harvested, washed with double-distilled water, diluted, and porated in the presence of 1 microgram of pGB301 DNA with a Transfector 100 (BTX, Inc., San Diego, Calif.) or a Gene Pulser (Bio-Rad Laboratories, Richmond, Calif.). Transformants were recovered at consistently higher efficiencies for cells grown in FMC or RPMI 1640 (10(3) to 10(4) transformants per micrograms of DNA) than for cells grown in M17-Glu (10(1) to 10(2) transformants per micrograms of DNA). Other parameters influencing electroporation of L. lactis cells grown in chemically defined media were growth phase and final concentration of cells, concentration of plasmid DNA, voltage achieved during poration, and expression conditions. A high degree of variability in transformation efficiencies was evident for replicate samples of cells pulsed with either electroporation machine. A trend toward decreased variability was observed for duplicate samples of cells prepared on the same day. In addition, storage studies done with a large batch of cells prepared on the same day indicated that freezing dry cell pellets at -60 degrees C had no deleterious effect on transformation efficiencies over a 30-day period when a new 0.2-cm cuvette was used for porating each sample. PMID:2513778

  14. Plasma cell-free mitochondrial DNA declines in response to prolonged moderate aerobic exercise.

    PubMed

    Shockett, Penny E; Khanal, Januka; Sitaula, Alina; Oglesby, Christopher; Meachum, William A; Castracane, V Daniel; Kraemer, Robert R

    2016-01-01

    Increased plasma cell-free mitochondrial DNA (cf-mDNA), a damage-associated molecular pattern (DAMP) produced by cellular injury, contributes to neutrophil activation/inflammation in trauma patients and arises in cancer and autoimmunity. To further understand relationships between cf-mDNA released by tissue injury, inflammation, and health benefits of exercise, we examined cf-mDNA response to prolonged moderate aerobic exercise. Seven healthy moderately trained young men (age = 22.4 ± 1.2) completed a treadmill exercise trial for 90 min at 60% VO2 max and a resting control trial. Blood was sampled immediately prior to exercise (0 min = baseline), during (+18, +54 min), immediately after (+90 min), and after recovery (R40). Plasma was analyzed for cf-mDNA, IL-6, and lactate. A significant difference in cf-mDNA response was observed between exercise and control trials, with cf-mDNA levels reduced during exercise at +54 and +90 (with or without plasma volume shift correction). Declines in cf-mDNA were accompanied by increased lactate and followed by an increase in IL-6, suggesting a temporal association with muscle stress and inflammatory processes. Our novel finding of cf-mDNA decline with prolonged moderate treadmill exercise provides evidence for increased clearance from or reduced release of cf-mDNA into the blood with prolonged exercise. These studies contrast with previous investigations involving exhaustive short-term treadmill exercise, in which no change in cf-mDNA levels were reported, and contribute to our understanding of differences between exercise- and trauma-induced inflammation. We propose that transient declines in cf-mDNA may induce health benefits, by reducing systemic inflammation.

  15. Longitudinal Differences in Aerobic Capacity between Children with Sickle Cell Anemia and Matched Controls

    PubMed Central

    Watson, Andrew; Liem, Robert I.; Lu, Zengqi; Saville, Ben; Acra, Sari; Shankar, Sadhna; Buchowski, Maciej

    2014-01-01

    Background The purpose of this study was to compare longitudinal trajectories of maximal aerobic capacity in children with sickle cell anemia (SCA) and matched healthy controls, and explore whether these trajectories were associated with selected physiologic variables. Procedures Children with SCA (n=33) and healthy controls (n=30) matched at baseline for race, sex, Tanner stage, height, and weight completed three consecutive annual fitness assessments (VO2peak). Data were compared between the groups at each time point and within groups over time. Change in VO2peak between the two groups over time was assessed using a linear mixed model with age, sex, fat-free mass (FFM), Tanner stage, and hemoglobin (Hgb) concentration as covariates. Results At baseline, children with SCA had significantly lower Hgb concentration (8.9 vs. 13.7 g/dL, p<0.001) and relative VO2peak (24.2 vs. 27.9 ml/kg/min, p=0.006) than healthy controls. Over time, children with SCA had smaller increases than healthy controls in VO2peak (−0.1 and +4.9 ml/kg/min, p<0.001), Tanner stage at year 2 (15% and 66% Tanner 4, p<0.001), and FFM (+4.0 and +6.8 kg, p=0.02). Changes in Hgb concentration did not differ between groups (+0.03 and +0.09 g/dL, p=1.0). After adjusting for age, sex, Tanner stage, FFM, and Hgb concentration the differences in change in VO2peak over time remained significant (p<0.001). Conclusion Children with SCA demonstrate lower relative VO2peak compared to healthy children and the difference increases over time. The difference in VO2peak trajectories between the two groups during puberty remains significant after adjusting for age, sex, FFM, Tanner stage, and Hgb concentration. PMID:25556359

  16. Comparison of electrogenic capabilities of microbial fuel cell with different light power on algae grown cathode.

    PubMed

    Juang, D F; Lee, C H; Hsueh, S C

    2012-11-01

    Electricity generation capabilities of microbial fuel cell with different light power on algae grown cathode were compared. Results showed that microbial fuel cell with 6 and 12W power of light always produced higher voltage and power density than with 18 and 26W. Similarly, microbial fuel cell with 6 and 12W of light power always displayed higher Coulombic efficiency and specific power than the one with 18 and 26W. The results also showed that microbial fuel cell with covered anodic chamber always displayed higher voltage, power density, Coulombic efficiency and specific power than the one without covered anodic chamber. Binary quadratic equations can be used to express the relationships between the light power and the voltage, power density, Coulombic efficiency and specific power. Although lower power of light on algae grown cathode and covering anodic chamber will increase system's electricity production, they will not significantly reduce its internal resistance.

  17. Osmotic Adjustment of Cultured Tobacco Cells (Nicotiana tabacum var. Samsum) Grown on Sodium Chloride 1

    PubMed Central

    Heyser, James W.; Nabors, Murray W.

    1981-01-01

    Tobacco cell cultures (var. Samsum) were grown on increasing levels of NaCl to select variants for increased salt tolerance. The osmotic adjustment of NaCl-adapted and nonadapted cell lines was studied. Both cell lines were grown on modified Linsmaier and Skoog medium with or without NaCl. Few differences were found in the response of adapted and nonadapted lines to NaCl. The concentrations of sugars, Na+, Cl−, and NO3− were identical in the cells and medium. Potassium and amino acids were accumulated by the cells. All of the above solutes accounted for 80 to 90% of the osmotic potential for both cell lines when grown on basal medium with or without NaCl. The osmotic potential of growing cells was always 1 to 3 bars more negative than that of the medium. During the first 10 days culture, the cells hydrolyzed the 117 millimolar sucrose present in the fresh media, and the media became more negative by 3 bars. Growing cells absorbed and metabolized the sugars, NH4+, and NO3− during the next 25 days, and the osmotic potential of the media and cells became less negative. The addition of 130 millimolar NaCl made the media and cells osmotically more negative by 6 bars throughout the growth cycle, as compared with cells growing on basal medium. The efflux of cellular solutes during distilled H2O washes was resolved into two components. The fast component (0.6 to 1.7 minutes half-time) included solutes of the free space and cytoplasm, whereas the slow component (1.6 to 4.9 hours half-time) represented the vacuolar solutes. Sodium and Cl− were present in the vacuole. No differences were observed in the solute efflux between the adapted and nonadapted cell lines. PMID:16661743

  18. Detailed Structural and Quantitative Analysis Reveals the Spatial Organization of the Cell Walls of in Vivo Grown Mycobacterium leprae and in Vitro Grown Mycobacterium tuberculosis*

    PubMed Central

    Bhamidi, Suresh; Scherman, Michael S.; Jones, Victoria; Crick, Dean C.; Belisle, John T.; Brennan, Patrick J.; McNeil, Michael R.

    2011-01-01

    The cell wall of mycobacteria consists of an outer membrane, analogous to that of Gram-negative bacteria, attached to the peptidoglycan (PG) via a connecting polysaccharide arabinogalactan (AG). Although the primary structure of these components is fairly well deciphered, issues such as the coverage of the PG layer by covalently attached mycolates in the outer membrane and the spatial details of the mycolic acid attachment to the arabinan have remained unknown. It is also not understood how these components work together to lead to the classical acid-fast staining of mycobacteria. Because the majority of Mycobacterium tuberculosis bacteria in established experimental animal infections are acid-fast negative, clearly cell wall changes are occurring. To address both the spatial properties of mycobacterial cell walls and to begin to study the differences between bacteria grown in animals and cultures, the cell walls of Mycobacterium leprae grown in armadillos was characterized and compared with that of M. tuberculosis grown in culture. Most fundamentally, it was determined that the cell wall of M. leprae contained significantly more mycolic acids attached to PG than that of in vitro grown M. tuberculosis (mycolate:PG ratios of 21:10 versus 16:10, respectively). In keeping with this difference, more arabinogalactan (AG) molecules, linking the mycolic acids to PG, were found. Differences in the structures of the AG were also found; the AG of M. leprae is smaller than that of M. tuberculosis, although the same basic structural motifs are retained. PMID:21555513

  19. Detailed structural and quantitative analysis reveals the spatial organization of the cell walls of in vivo grown Mycobacterium leprae and in vitro grown Mycobacterium tuberculosis.

    PubMed

    Bhamidi, Suresh; Scherman, Michael S; Jones, Victoria; Crick, Dean C; Belisle, John T; Brennan, Patrick J; McNeil, Michael R

    2011-07-01

    The cell wall of mycobacteria consists of an outer membrane, analogous to that of gram-negative bacteria, attached to the peptidoglycan (PG) via a connecting polysaccharide arabinogalactan (AG). Although the primary structure of these components is fairly well deciphered, issues such as the coverage of the PG layer by covalently attached mycolates in the outer membrane and the spatial details of the mycolic acid attachment to the arabinan have remained unknown. It is also not understood how these components work together to lead to the classical acid-fast staining of mycobacteria. Because the majority of Mycobacterium tuberculosis bacteria in established experimental animal infections are acid-fast negative, clearly cell wall changes are occurring. To address both the spatial properties of mycobacterial cell walls and to begin to study the differences between bacteria grown in animals and cultures, the cell walls of Mycobacterium leprae grown in armadillos was characterized and compared with that of M. tuberculosis grown in culture. Most fundamentally, it was determined that the cell wall of M. leprae contained significantly more mycolic acids attached to PG than that of in vitro grown M. tuberculosis (mycolate:PG ratios of 21:10 versus 16:10, respectively). In keeping with this difference, more arabinogalactan (AG) molecules, linking the mycolic acids to PG, were found. Differences in the structures of the AG were also found; the AG of M. leprae is smaller than that of M. tuberculosis, although the same basic structural motifs are retained.

  20. High-efficiency AlGaInP solar cells grown by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Faucher, J.; Sun, Y.; Jung, D.; Martin, D.; Masuda, T.; Lee, M. L.

    2016-10-01

    AlGaInP is an ideal material for ultra-high efficiency, lattice-matched multi-junction solar cells grown by molecular beam epitaxy (MBE) because it can be grown lattice-matched to GaAs with a wide 1.9-2.2 eV bandgap. Despite this potential, AlGaInP grown by molecular beam epitaxy (MBE) has yet to be fully explored, with the initial 2.0 eV devices suffering from poor performance due to low minority carrier diffusion lengths in both the emitter and base regions of the solar cell. In this work, we show that implementing an AlGaInP graded layer to introduce a drift field near the front surface of the device enabled greatly improved internal quantum efficiency (IQE) across all wavelengths. In addition, optimizing growth conditions and post-growth annealing improved the long-wavelength IQE and the open-circuit voltage of the cells, corresponding to a 3× increase in diffusion length in the base. Taken together, this work demonstrates greatly improved IQE, attaining peak values of 95%, combined with an uncoated AM1.5G efficiency of 10.9%, double that of previously reported MBE-grown devices.

  1. Metabolic network analysis of DB1 melanoma cells: how much energy is derived from aerobic glycolysis?

    PubMed

    Shestov, A A; Mancuso, A; Leeper, D B; Glickson, J D

    2013-01-01

    A network model has been developed for analysis of tumor glucose metabolism from (13)C MRS isotope exchange kinetic data. Data were obtained from DB1 melanoma cells grown on polystyrene microcarrier beads contained in a 20-mm diameter perfusion chamber in a 9.4 T Varian NMR spectrometer; the cells were perfused with 26 mM [1,6-(13)C(2)]glucose under normoxic conditions and 37°C and monitored by (13)C NMR spectroscopy for 6 h. The model consists of ∼150 differential equations in the cumomer formalism describing glucose and lactate transport, glycolysis, TCA cycle, pyruvate cycling, the pentose shunt, lactate dehydrogenase, the malate-aspartate and glycerophosphate shuttles, and various anaplerotic pathways. The rate of oxygen consumption (CMRO(2)) was measured polarographically by monitoring differences in pO(2). The model was validated by excellent agreement between model predicted and experimentally measured values of CMRO(2) and glutamate pool size. Assuming a P/O ratio of 2.5 for NADH and 1.5 for FADH2, ATP production was estimated as 46% glycolytic and 54% mitochondrial based on average values of CMRO(2) and glycolytic flux (two experiments).

  2. Diversity of the exoproteome of Fusarium graminearum grown on plant cell wall.

    PubMed

    Phalip, Vincent; Delalande, François; Carapito, Christine; Goubet, Florence; Hatsch, Didier; Leize-Wagner, Emmanuelle; Dupree, Paul; Dorsselaer, Alain Van; Jeltsch, Jean-Marc

    2005-12-01

    The exoproteome of the fungus Fusarium graminearum grown on glucose and on hop (Humulus lupulus, L.) cell wall has been investigated. The culture medium was found to contain a higher quantity of proteins and the proteins are more diverse when the fungus is grown on cell wall. Using both 1D and 2D electrophoresis followed by mass spectrometry analysis and protein identification based on similarity searches, 84 unique proteins were identified in the cell wall-grown fungal exoproteome. Many are putatively implicated in carbohydrate metabolism, mainly in cell wall polysaccharide degradation. The predicted carbohydrate-active enzymes fell into 24 different enzymes classes, and up to eight different proteins within a same class are secreted. This indicates that fungal metabolism becomes oriented towards synthesis and secretion of a whole arsenal of enzymes able to digest almost the complete plant cell wall. Cellobiohydrolase is one of the only four proteins found both after growth on glucose and on plant cell wall and we propose that this enzyme could act as a sensor of the extracellular environment. Extensive knowledge of this very diverse F. graminearum exoproteome is an important step towards the full understanding of Fusarium/plants interactions.

  3. Studies on the replication of Mayaro virus grown in interferon treated cells.

    PubMed

    Rebello, M C; Fonseca, M E; Marinho, J O; Rebello, M A

    1994-01-01

    Mayaro virus grown in interferon treated infected cells has been characterized with regard to its ability to replicate in vertebrate (TC7) and invertebrate (Aedes albopictus) cells. Virus purified from interferon treated TC7 cells adsorbs and penetrates to the same extent as the control virus. During infection, these virus particles caused inhibition of host protein synthesis and synthesized the same spectrum of viral proteins as normal virus. This population however, was apparently more sensitive to interferon treatment. Electron microscopy of TC7 cells showed the presence of numerous aberrant virus particles budding from the plasma membrane.

  4. Homojunction GaAs solar cells grown by close space vapor transport

    SciTech Connect

    Boucher, Jason W.; Ritenour, Andrew J.; Greenaway, Ann L.; Aloni, Shaul; Boettcher, Shannon W.

    2014-06-08

    We report on the first pn junction solar cells grown by homoepitaxy of GaAs using close space vapor transport (CSVT). Cells were grown both on commercial wafer substrates and on a CSVT absorber film, and had efficiencies reaching 8.1%, open circuit voltages reaching 909 mV, and internal quantum efficiency of 90%. The performance of these cells is partly limited by the electron diffusion lengths in the wafer substrates, as evidenced by the improved peak internal quantum efficiency in devices fabricated on a CSVT absorber film. Unoptimized highly-doped n-type emitters also limit the photocurrent, indicating that thinner emitters with reduced doping, and ultimately wider band gap window or surface passivation layers, are required to increase the efficiency.

  5. Cell envelope proteins of Staphylococcus epidermidis grown in vivo in a peritoneal chamber implant.

    PubMed Central

    Modun, B; Williams, P; Pike, W J; Cockayne, A; Arbuthnott, J P; Finch, R; Denyer, S P

    1992-01-01

    Staphylococcus epidermidis was grown in vivo in chambers implanted intraperitoneally in rats. The cell wall and cytoplasmic membrane protein profiles of the in vivo-grown organisms were compared with those of S. epidermidis grown in vitro in nutrient broth (NB), in iron-restricted NB, or in pooled human peritoneal dialysate (HPD). Compared with growth in broth and in common with growth in HPD, growth in vivo in chambers resulted in the repression of many S. epidermidis wall proteins, with proteins of 27, 42, 54, and 70 kDa predominating. Growth in vivo also resulted in the induction of two iron-repressible cytoplasmic membrane proteins of 32 and 36 kDa, which were also present in staphylococci grown in HPD and in iron-restricted NB. Immunoblotting experiments revealed that in sera taken 21 days after inoculation of the intraperitoneal chambers, the predominant antibody response to cell envelope proteins was directed against the 32- and 36-kDa iron-repressible membrane proteins. Images PMID:1587623

  6. Electrooptical monitoring of cell polarizability and cell size in aerobic Escherichia coli batch cultivations.

    PubMed

    Junne, Stefan; Nicolas Cruz-Bournazou, M; Angersbach, Alexander; Götz, Peter

    2010-09-01

    The time-dependent development of cell polarizability and length in Escherichia coli batch fermentations were observed at-line with electrooptical measurements. While using a measurement system with fully automated sample preparation, the development of these properties can be observed with a comparable high frequency (six measurements per hour). The polarizability as well as the mean cell length both increase soon after inoculation and then decline from the growth phase on until the stationary phase is reached. Based on the dynamic behavior of polarizability, the growth phase can be divided into four distinct stages. Changes in the cultivation temperature or the pre-cultivation conditions lead to alterations in the development of the polarizability and mean cell length. Based on the frequency disperse of polarizability measured at four different frequencies from 210 to 2,100 kHz, a prediction model is established that is based on the relation of the polarizability to the metabolic activity. Applying multi-linear partial least squares methods (N-PLS), the model is able to predict the specific acetate synthesis and uptake with a root mean square error of prediction of 0.19 (6% of the mean). The method represents a tool for characterization of different stages with respect to microbial metabolic activity and the energy balance during batch cultivations.

  7. Effects of method of detachment on electrophoretic mobility of mammalian cells grown in monolayer culture

    NASA Technical Reports Server (NTRS)

    Plank, L. D.; Kunze, M. E.; Todd, P. W.

    1985-01-01

    A variety of proteolytic and micolytic enzumes, mechanical procedures, and changes in the ionic environment, especially Ca chelation, are used for dispersal of monolayer grown cells. If either chelating agents or mechanical dispersion are used alone, the cell yield is often low and suspensions of single cells are difficult to obtain. Confluent monolayers treated with EDTA tend to be released from their surfaces in sheets, and clumps of cells remain even after further incubation in EDTA. Crude trypsin is the most popular dispersal agent and is known to contain a variety of contaminating enzymes which contribute to the dispersal of cells. A variety of cell injuries resulting from the activity of proteolytic enzymes are reported. It is shown that crystalline trypsin is least harmful to cell integrity as judged by trypan blue uptake.

  8. Phosgene Effects on F-Actin in Cells Grown from Pulmonary Tissues

    DTIC Science & Technology

    1993-05-13

    Plato, N., Alexandersson, R ., Eklund, A., and Falkenberg , C. (1991). Pulmonary reactions caused by welding-induced decomposed trichlorethylene. Chest 99...CY) CO 0= Phosgene Effects on F-actin in Cells Grown on from Pulmonary Tissues I R . Werrlein, J. Madren-Whalley and S.D. Kirby United States Army...shape, the image in Fig. 1 shows organization that was characteristic of F-actin in untreated and sham-treated control populations. B 4000- DPB (7 r 3000

  9. Aging impairs osteoblast differentiation of mesenchymal stem cells grown on titanium by favoring adipogenesis

    PubMed Central

    ABUNA, Rodrigo Paolo Flores; STRINGHETTA-GARCIA, Camila Tami; FIORI, Leonardo Pimentel; DORNELLES, Rita Cassia Menegati; ROSA, Adalberto Luiz; BELOTI, Marcio Mateus

    2016-01-01

    ABSTRACT Aging negatively affects bone/titanium implant interactions. Our hypothesis is that the unbalance between osteogenesis and adipogenesis induced by aging may be involved in this phenomenon. Objective We investigated the osteoblast and adipocyte differentiation of mesenchymal stem cells (MSCs) from young and aged rats cultured on Ti. Material and Methods Bone marrow MSCs derived from 1-month and 21-month rats were cultured on Ti discs under osteogenic conditions for periods of up to 21 days and osteoblast and adipocyte markers were evaluated. Results Cell proliferation, alkaline phosphatase (ALP) activity, extracellular matrix mineralization and gene expression of RUNX2, osterix, ALP, bone sialoprotein, osteopontin, and osteocalcin were reduced in cultures of 21-month rats compared with 1-month rats grown on Ti. Gene expression of PPAR-γ , adipocyte protein 2, and resistin and lipid accumulation were increased in cultures of 21-month rats compared with 1-month rats grown on the same conditions. Conclusions These results indicate that the lower osteogenic potential of MSCs derived from aged rats compared with young rats goes along with the higher adipogenic potential in cultures grown on Ti surface. This unbalance between osteoblast and adipocyte differentiation should be considered in dental implant therapy to the elderly population. PMID:27556209

  10. Lithium induces ER stress and N-glycan modification in galactose-grown Jurkat cells.

    PubMed

    Nagy, Tamás; Frank, Dorottya; Kátai, Emese; Yahiro, Rikki K K; Poór, Viktor S; Montskó, Gergely; Zrínyi, Zita; Kovács, Gábor L; Miseta, Attila

    2013-01-01

    We previously reported that lithium had a significant impact on Ca(2+) regulation and induced unfolded protein response (UPR) in yeast cells grown on galactose due to inhibition of phosphoglucomutase (PGM), however the exact mechanism has not been established yet. In this study, we analysed lithium's effect in galactose-fed cells to clarify whether these ER-related changes are the result of a relative hypoglycemic state. Furthermore, we investigated whether the alterations in galactose metabolism impact protein post-translational modifications. Thus, Jurkat cells were incubated in glucose or galactose containing media with or without lithium treatment. We found that galactose-fed and lithium treated cells showed better survivability than fasting cells. We also found higher UDP-Hexose and glycogen levels in these cells compared to fasting cells. On the other hand, the UPR (X-box binding protein 1 mRNA levels) of galactose-fed and lithium treated cells was even greater than in fasting cells. We also found increased amount of proteins that contained N-linked N-acetyl-glucosamine, similar to what was reported in fasting cells by a recent study. Our results demonstrate that lithium treatment of galactose-fed cells can induce stress responses similar to hypoglycemia, however cell survival is still secured by alternative pathways. We propose that clarifying this process might be an important addition toward the better understanding of the molecular mechanisms that regulate ER-associated stress response.

  11. Longevity of U cells of differentiated yeast colonies grown on respiratory medium depends on active glycolysis.

    PubMed

    Čáp, Michal; Váchová, Libuše; Palková, Zdena

    2015-01-01

    Colonies of Saccharomyces cerevisiae laboratory strains pass through specific developmental phases when growing on solid respiratory medium. During entry into the so-called alkali phase, in which ammonia signaling is initiated, 2 prominent cell types are formed within the colonies: U cells in upper colony regions, which have a longevity phenotype and activate the expression of a large number of metabolic genes, and L cells in lower regions, which die more quickly and exhibit a starvation phenotype. Here, we performed a detailed analysis of the activities of enzymes of central carbon metabolism in lysates of both cell types and determined several fermentation end products, showing that previously reported expression differences are reflected in the different enzymatic capabilities of each cell type. Hence, U cells, despite being grown on respiratory medium, behave as fermenting cells, whereas L cells rely on respiratory metabolism and possess active gluconeogenesis. Using a spectrum of different inhibitors, we showed that glycolysis is essential for the formation, and particularly, the survival of U cells. We also showed that β-1,3-glucans that are released from the cell walls of L cells are the most likely source of carbohydrates for U cells.

  12. Epitaxially grown polycrystalline silicon thin-film solar cells on solid-phase crystallised seed layers

    NASA Astrophysics Data System (ADS)

    Li, Wei; Varlamov, Sergey; Xue, Chaowei

    2014-09-01

    This paper presents the fabrication of poly-Si thin film solar cells on glass substrates using seed layer approach. The solid-phase crystallised P-doped seed layer is not only used as the crystalline template for the epitaxial growth but also as the emitter for the solar cell structure. This paper investigates two important factors, surface cleaning and intragrain defects elimination for the seed layer, which can greatly influence the epitaxial grown solar cell performance. Shorter incubation and crystallisation time is observed using a simplified RCA cleaning than the other two wet chemical cleaning methods, indicating a cleaner seed layer surface is achieved. Cross sectional transmission microscope images confirm a crystallographic transferal of information from the simplified RCA cleaned seed layer into the epi-layer. RTA for the SPC seed layer can effectively eliminate the intragrain defects in the seed layer and improve structural quality of both of the seed layer and the epi-layer. Consequently, epitaxial grown poly-Si solar cell on the RTA treated seed layer shows better solar cell efficiency, Voc and Jsc than the one on the seed layer without RTA treatment.

  13. Increased liposome-mediated gene transfer into haematopoietic cells grown in adhesion to stromal or fibroblast cell line monolayers.

    PubMed

    Marit, G; Cao, Y; Froussard, P; Ripoche, J; Dupouy, M; Elandaloussi, A; Lacombe, F; Mahon, F X; Keller, H; Pla, M; Reiffers, J; Theze, J

    2000-01-01

    We investigated transfection rates of CD34+ haematopoietic progenitor cells (HPC) or haematopoietic cell lines (TF-1, KG1a and K562) using the LacZ gene as a reporter and cationic liposomes. The transfection efficiency of CD34+ haematopoietic progenitor cells (HPC) or TF-1, KG1a and K562 grown in suspension is very low (average percentage of 0.013 for HPC and 0.03 for cell lines). Adhesion of HPC or cell lines to plates by immunological or physical methods significantly enhances transfection efficiency; however, the percentage of transfected cells still remained low. We found that adhesion of TF-1, KG1a and K562 HC to MS-5 stroma cells or NIH-3T3 fibroblast cells increased transfection efficiency. Under these conditions transfection is achieved in 11.2-25% (mean 18.30%) for the cell lines and 13.6% (range 8.2-24.2%) for CD34+ HPC. These results indicate that liposome-mediated transfection of HC is significantly increased when cells are grown in adherence to stroma or fibroblast monolayers.

  14. Aerobic Tennis.

    ERIC Educational Resources Information Center

    Stewart, Michael J.; Ahlschwede, Robert

    1989-01-01

    Increasing the aerobic nature of tennis drills in the physical education class may be necessary if tennis is to remain a part of the public school curriculum. This article gives two examples of drills that can be modified by teachers to increase activity level. (IAH)

  15. Cyclic-radiation response of murine fibrosarcoma cells grown as pulmonary nodules

    SciTech Connect

    Grdina, D.J.; Hunter, N.

    1982-10-01

    The radiation age response of murine fibrosarcoma (FSa) cells grown as pulmonary nodules in C/sub 3/Hf/Kam mice was determined. FSa cells were irradiated in vivo either with 10 Gy as 14 day-old lung tumors (i.e., artificial macrometastases) prior to cell separation or with 5 Gy as single cells trapped in the lungs of recipient mice (i.e., artificial micrometastases) following cell separation and synchronization by centrifugal elutriation. Flow microfluorometry (FMF) was used to determine cell-cycle parameters and the relative synchrony of the separated populations, as well as the percent contamination of normal diploid cells in each of the tumor cell populations. Tumor populations containing up to 90% G/sub 1/, 60% S-, and 75% G/sub 2/+M-phase tumor cells were obtained. Cell clonogenicity, determined using a lung colony assay, ranged from 0.7 to 6% for control FSa cells from the various elutriator fractions. The radiation sensitivity of these separated cell populations varied by a factor of 6, regardless of whether the cells were irradiated as artificial micro or macro-metastases. In each experiment, tumor populations most enriched in s-phase cells exhibited the greatest radiation sensitivity. To confirm that these populations were highly enriched in S-phase cells and to demonstrate that they were more radiosensitive than FSa cells in other parts of the cell cycle, the elutriated tumor populations were exposed to either suicide labeling by high specific activity tritiated thymidine or hydroxyurea. The resultant age response curves were qualitatively similar to those obtained following irradiation and reflected the S-phase sensitivity of FSa cells to these agents.

  16. InGaAsP Solar Cells Grown by Hydride Vapor Phase Epitaxy

    SciTech Connect

    Jain, Nikhil; Simon, John; Schulte, Kevin L.; Dippo, Patricia; Young, Michelle; Young, David L.; Ptak, Aaron J.

    2016-11-21

    Hydride vapor phase epitaxy (HVPE) has recently reemerged as a low-cost, high-throughput alternative to metalorganic chemical vapor deposition (MOCVD) for the growth of high-efficiency III-V solar cells. Quaternary InGaAsP solar cells in the bandgap range of ~1.7-1.8 eV are promising top-cell candidates for integration in Ill-V/Si tandem cells with projected one-sun efficiencies exceeding 30%. In this work, we report on the development of lattice-matched InGaAsP solar cells grown on GaAs substrates via HVPE at very high growth rates of ~0.7 um/min. We demonstrate prototype 1.7 eV InGaAsP solar cells with an open-circuit voltage of 1.11 V. The short-circuit current is limited by the lack of a window layer in these early stage devices. The photo response of 1.7 InGaAsP solar cell with ~1.1 um thick base layer is found to be nearly insensitive to variation in p-type base doping concentration in the range from Na - 4x1016 to - 1x1017 cm-3, indicating an effective carrier collection length on the order of - 1.1 um or higher in our devices. These initial InGaAsP cell results are encouraging and highlight the viability of HVPE to produce mixed arsenide-phosphide solar cells grown lattice-matched on GaAs.

  17. Ge nanopillar solar cells epitaxially grown by metalorganic chemical vapor deposition

    PubMed Central

    Kim, Youngjo; Lam, Nguyen Dinh; Kim, Kangho; Park, Won-Kyu; Lee, Jaejin

    2017-01-01

    Radial junction solar cells with vertically aligned wire arrays have been widely studied to improve the power conversion efficiency. In this work, we report the first Ge nanopillar solar cell. Nanopillar arrays are selectively patterned on p-type Ge (100) substrates using nanosphere lithography and deep reactive ion etching processes. Nanoscale radial and planar junctions are realized by an n-type Ge emitter layer which is epitaxially grown by MOCVD using isobutylgermane. In situ epitaxial surface passivation is employed using an InGaP layer to avoid high surface recombination rates and Fermi level pinning. High quality n-ohmic contact is realized by protecting the top contact area during the nanopillar patterning. The short circuit current density and the power conversion efficiency of the Ge nanopillar solar cell are demonstrated to be improved up to 18 and 30%, respectively, compared to those of the Ge solar cell with a planar surface. PMID:28209964

  18. Ge nanopillar solar cells epitaxially grown by metalorganic chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Kim, Youngjo; Lam, Nguyen Dinh; Kim, Kangho; Park, Won-Kyu; Lee, Jaejin

    2017-02-01

    Radial junction solar cells with vertically aligned wire arrays have been widely studied to improve the power conversion efficiency. In this work, we report the first Ge nanopillar solar cell. Nanopillar arrays are selectively patterned on p-type Ge (100) substrates using nanosphere lithography and deep reactive ion etching processes. Nanoscale radial and planar junctions are realized by an n-type Ge emitter layer which is epitaxially grown by MOCVD using isobutylgermane. In situ epitaxial surface passivation is employed using an InGaP layer to avoid high surface recombination rates and Fermi level pinning. High quality n-ohmic contact is realized by protecting the top contact area during the nanopillar patterning. The short circuit current density and the power conversion efficiency of the Ge nanopillar solar cell are demonstrated to be improved up to 18 and 30%, respectively, compared to those of the Ge solar cell with a planar surface.

  19. Voc Degradation in TF-VLS Grown InP Solar Cells

    SciTech Connect

    Sun, Yubo; Sun, Xingshu; Johnston, Steve; Sutter-Fella, Carolin M.; Hettick, Mark; Javey, Ali; Bermel, Peter

    2016-11-21

    Here we consider two hypotheses to explain the open-circuit voltage (VOC) degradation observed in thin-film vapor-liquid-solid (TF-VLS) grown p-type InP photovoltaic cells: bandgap narrowing and local shunting. First, a bandgap (Eg) narrowing effect is hypothesized, based on the surface inhomogeneity of VLS InP captured by the photoluminescence (PL) image. The PL data was used to estimate a spatially-resolved active VOC across surface of the InP sample. Combining this data with the effective Jsc allowed an assessment of the I-V characteristics of individual unit cells. Next, an H-SPICE diode compact model was utilized to reproduce the I-V characteristics of the whole sample. We find a good fit to the I-V performance of TF-VLS grown InP solar cell. Second, a local shunting effect was also considered as an alternative explanation of the VOC degradation effect. Again, PL image data was used, and small local shunt resistance was added in arbitrary elementary unit cells to represent certain dark spots seen in the PL image and dictate the VOC degradation occurred in the sample.

  20. Electrical properties of dog tracheal epithelial cells grown in monolayer culture.

    PubMed

    Coleman, D L; Tuet, I K; Widdicombe, J H

    1984-03-01

    Epithelial cells from dog trachea, when grown in tissue culture, formed confluent monolayers 5-6 days after plating. After 8-10 days, domes [mean diam 356 +/- (SE) 53 micron] appeared in monolayers grown in collagen-coated flasks. When grown on polycarbonate filters coated with collagen, a detectable resistance (greater than 5 omega X cm2) and transepithelial potential difference (PD) (greater than 0.1 mV) developed 6 days after plating and increased to approximately 15 omega X cm2 and 15 mV at 10 days. Serosal ouabain (10(-4) M) abolished PD and short-circuit current (Isc). Luminal ouabain had no effect. Luminal amiloride (10(-4) M) and serosal bumetanide (10(-4) M) each decreased PD and Isc. However, a combination of both of these drugs did not abolish Isc. Isoproterenol (10(-5) M), dibutyryl adenosine 3',5'-cyclic monophosphate (10(-3) M), vasoactive intestinal peptide (10(-7) M), prostaglandin (PG) E2 (10(-5) M), PGF2 alpha (10(-5) M), and bradykinin (10(-5) M) each increased PD and Isc. Thus these monolayer cultures maintain electrical properties resembling those of the original tissue. This preparation may prove useful for the study of water and ion transport by airway epithelia.

  1. Mitochondrial aerobic respiration is activated during hair follicle stem cell differentiation, and its dysfunction retards hair regeneration

    PubMed Central

    Tang, Yan; Luo, Binping; Deng, Zhili; Wang, Ben; Liu, Fangfen; Li, Jinmao; Shi, Wei; Xie, Hongfu; Hu, Xingwang

    2016-01-01

    Background. Emerging research revealed the essential role of mitochondria in regulating stem/progenitor cell differentiation of neural progenitor cells, mesenchymal stem cells and other stem cells through reactive oxygen species (ROS), Notch or other signaling pathway. Inhibition of mitochondrial protein synthesis results in hair loss upon injury. However, alteration of mitochondrial morphology and metabolic function during hair follicle stem cells (HFSCs) differentiation and how they affect hair regeneration has not been elaborated upon. Methods. We compared the difference in mitochondrial morphology and activity between telogen bulge cells and anagen matrix cells. Expression levels of mitochondrial ROS and superoxide dismutase 2 (SOD2) were measured to evaluate redox balance. In addition, the level of pyruvate dehydrogenase kinase (PDK) and pyruvate dehydrogenase (PDH) were estimated to present the change in energetic metabolism during differentiation. To explore the effect of the mitochondrial metabolism on regulating hair regeneration, hair growth was observed after application of a mitochondrial respiratory inhibitor upon hair plucking. Results. During HFSCs differentiation, mitochondria became elongated with more abundant organized cristae and showed higher activity in differentiated cells. SOD2 was enhanced for redox balance with relatively stable ROS levels in differentiated cells. PDK increased in HFSCs while differentiated cells showed enhanced PDH, indicating that respiration switched from glycolysis to oxidative phosphorylation during differentiation. Inhibiting mitochondrial respiration in differentiated hair follicle cells upon hair plucking repressed hair regeneration in vivo. Conclusions. Upon HFSCs differentiation, mitochondria are elongated with more abundant cristae and show higher activity, accompanying with activated aerobic respiration in differentiated cells for higher energy supply. Also, dysfunction of mitochondrial respiration delays hair

  2. Assessing individual radial junction solar cells over millions on VLS-grown silicon nanowires.

    PubMed

    Yu, Linwei; Rigutti, Lorenzo; Tchernycheva, Maria; Misra, Soumyadeep; Foldyna, Martin; Picardi, Gennaro; Roca i Cabarrocas, Pere

    2013-07-12

    Silicon nanowires (SiNWs) grown on low-cost substrates provide an ideal framework for the monolithic fabrication of radial junction photovoltaics. However, the quality of junction formation over a random matrix of SiNWs, fabricated via a vapor-liquid-solid (VLS) mechanism, has never been assessed in a realistic context. To address this, we probe the current response of individual radial junction solar cells under electron-beam and optical-beam excitations. Excellent current generation from the radial junction units, compared to their planar counterparts, has been recorded, indicating a high junction quality and effective doping in the ultra-thin SiNWs with diameters thinner than 20 nm. Interestingly, we found that the formation of radial junctions by plasma deposition can be quite robust against geometrical disorder and even the crossings of neighboring cell units. These results provide a strong support to the feasibility of building high-quality radial junction solar cells over high-throughput VLS-grown SiNWs on low-cost substrates.

  3. Assessing individual radial junction solar cells over millions on VLS-grown silicon nanowires

    NASA Astrophysics Data System (ADS)

    Yu, Linwei; Rigutti, Lorenzo; Tchernycheva, Maria; Misra, Soumyadeep; Foldyna, Martin; Picardi, Gennaro; Cabarrocas, Pere Roca i.

    2013-07-01

    Silicon nanowires (SiNWs) grown on low-cost substrates provide an ideal framework for the monolithic fabrication of radial junction photovoltaics. However, the quality of junction formation over a random matrix of SiNWs, fabricated via a vapor-liquid-solid (VLS) mechanism, has never been assessed in a realistic context. To address this, we probe the current response of individual radial junction solar cells under electron-beam and optical-beam excitations. Excellent current generation from the radial junction units, compared to their planar counterparts, has been recorded, indicating a high junction quality and effective doping in the ultra-thin SiNWs with diameters thinner than 20 nm. Interestingly, we found that the formation of radial junctions by plasma deposition can be quite robust against geometrical disorder and even the crossings of neighboring cell units. These results provide a strong support to the feasibility of building high-quality radial junction solar cells over high-throughput VLS-grown SiNWs on low-cost substrates.

  4. Intradialytic aerobic cycling exercise alleviates inflammation and improves endothelial progenitor cell count and bone density in hemodialysis patients

    PubMed Central

    Liao, Min-Tser; Liu, Wen-Chih; Lin, Fu-Huang; Huang, Ching-Feng; Chen, Shao-Yuan; Liu, Chuan-Chieh; Lin, Shih-Hua; Lu, Kuo-Cheng; Wu, Chia-Chao

    2016-01-01

    Abstract Inflammation, endothelial dysfunction, and mineral bone disease are critical factors contributing to morbidity and mortality in hemodialysis (HD) patients. Physical exercise alleviates inflammation and increases bone density. Here, we investigated the effects of intradialytic aerobic cycling exercise on HD patients. Forty end-stage renal disease patients undergoing HD were randomly assigned to either an exercise or control group. The patients in the exercise group performed a cycling program consisting of a 5-minute warm-up, 20 minutes of cycling at the desired workload, and a 5-minute cool down during 3 HD sessions per week for 3 months. Biochemical markers, inflammatory cytokines, nutritional status, the serum endothelial progenitor cell (EPC) count, bone mineral density, and functional capacity were analyzed. After 3 months of exercise, the patients in the exercise group showed significant improvements in serum albumin levels, the body mass index, inflammatory cytokine levels, and the number of cells positive for CD133, CD34, and kinase insert domain-conjugating receptor. Compared with the exercise group, the patients in the control group showed a loss of bone density at the femoral neck and no increases in EPCs. The patients in the exercise group also had a significantly greater 6-minute walk distance after completing the exercise program. Furthermore, the number of EPCs significantly correlated with the 6-minute walk distance both before and after the 3-month program. Intradialytic aerobic cycling exercise programs can effectively alleviate inflammation and improve nutrition, bone mineral density, and exercise tolerance in HD patients. PMID:27399127

  5. Proliferation and Differentiation Potential of Human Adipose-Derived Stem Cells Grown on Chitosan Hydrogel

    PubMed Central

    Debnath, Tanya; Ghosh, Sutapa; Potlapuvu, Usha Shalini; Kona, Lakshmi; Kamaraju, Suguna Ratnakar; Sarkar, Suprabhat; Gaddam, Sumanlatha; Chelluri, Lakshmi Kiran

    2015-01-01

    Applied tissue engineering in regenerative medicine warrants our enhanced understanding of the biomaterials and its function. The aim of this study was to evaluate the proliferation and differentiation potential of human adipose-derived stem cells (hADSCs) grown on chitosan hydrogel. The stability of this hydrogel is pH-dependent and its swelling property is pivotal in providing a favorable matrix for cell growth. The study utilized an economical method of cross linking the chitosan with 0.5% glutaraldehyde. Following the isolation of hADSCs from omentum tissue, these cells were cultured and characterized on chitosan hydrogel. Subsequent assays that were performed included JC-1 staining for the mitochondrial integrity as a surrogate marker for viability, cell proliferation and growth kinetics by MTT assay, lineage specific differentiation under two-dimensional culture conditions. Confocal imaging, scanning electron microscopy (SEM), and flow cytometry were used to evaluate these assays. The study revealed that chitosan hydrogel promotes cell proliferation coupled with > 90% cell viability. Cytotoxicity assays demonstrated safety profile. Furthermore, glutaraldehyde cross linked chitosan showed < 5% cytotoxicity, thus serving as a scaffold and facilitating the expansion and differentiation of hADSCs across endoderm, ectoderm and mesoderm lineages. Additional functionalities can be added to this hydrogel, particularly those that regulate stem cell fate. PMID:25746846

  6. Rabies veterinary virus vaccine produced in BHK-21 cells grown on microcarriers in a bioreactor.

    PubMed

    Gallegos Gallegos, R M; Espinosa Larios, E L; Ramos Ramírez, L; Kretschmer Schmid, R; Aguilar Setién, A

    1995-01-01

    BHK-21 cells were grown in microcarriers in the CELLIGEN CL 50 bioreactor to produce a stock of rabies veterinary virus vaccine PV (Pasteur virus) strain. Perfusion mode operation of this bioreactor produced between two- and fourfold larger yields (cells/ml) than traditional stationary cell culture systems (i.e., Blake, and Roller bottles or cell factory multitrays). The method employed harvested 281 of rabies virus in 200 h (infectivity titer 0.6 +/- 1.4 x 10(7) LD50 per ml) in a single operation. The risk of contamination is thus reduced when compared with traditional stationary methods which, in order to obtain the same amount of virus, would require the operation of 285 Blake bottles, or 143 Roller bottles, or 15 Cell Factory multitrays (10 trays). By perfusion mode operation of the bioreactor, 89% of the cell culture medium was recovered as vaccinal virus, which contrasts with the yield of only 50-59% using traditional cell culture systems. On the other hand, only 925 ml of fetal serum was required to obtain the 281 of rabies virus harvest as compared to the 3420 ml required by traditional methods.

  7. Human norovirus infection of caco-2 cells grown as a three-dimensional tissue structure.

    PubMed

    Straub, Timothy M; Bartholomew, Rachel A; Valdez, Catherine O; Valentine, Nancy B; Dohnalkova, Alice; Ozanich, Richard M; Bruckner-Lea, Cynthia J; Call, Douglas R

    2011-06-01

    Human norovirus (hNoV) infectivity was studied using a three-dimensional model of large intestinal epithelium. Large intestine Caco-2 cells were grown in rotating wall vessel bioreactors for 18-21 days at 37 degrees C and then transferred to 24-well tissue culture plates where they were infected with GI.1 and GII.4 human noroviruses collected from human challenge trials and various outbreak settings, respectively. Compared with uninfected cells, transmission micrographs of norovirus-infected cells displayed evidence of shortening or total loss of apical microvilli, and vacuolization. Quantitative reverse transcription real-time PCR (qRT-PCR) indicated an approximate 2-3 log10 increase in viral RNA copies for the infected cells. A passage experiment examined both the ability for continued viral RNA and viral antigen detection. In the passaged samples 1.01x10(6) copies ml(-1) were detected by qRT-PCR. Immune electron microscopy using primary antibody to hNoV GI.1 capsids in conjunction with 6 nm gold-labelled secondary antibodies was performed on crude cellular lysates. Localization of antibody was observed in infected but not for uninfected cells. Our present findings, coupled with earlier work with the three-dimensional small intestinal INT407 model, demonstrate the utility of 3-D cell culture methods to develop infectivity assays for enteric viruses that do not readily infect mammalian cell cultures.

  8. Characterization of Epitaxial Film Silicon Solar Cells Grown on Seeded Display Glass: Preprint

    SciTech Connect

    Young, D. L.; Grover, S.; Teplin, C.; Stradins, P.; LaSalvia, V.; Chuang, T. K.; Couillard, J. G.; Branz, H. M.

    2012-06-01

    We report characterizations of epitaxial film crystal silicon (c-Si) solar cells with open-circuit voltages (Voc) above 560 mV. The 2-um absorber cells are grown by low-temperature (<750 degrees C) hot-wire CVD (HWCVD) on Corning EAGLE XG display glass coated with a layer-transferred (LT) Si seed. The high Voc is a result of low-defect epitaxial Si (epi-Si) growth and effective hydrogen passivation of defects. The quality of HWCVD epitaxial growth on seeded glass substrates depends on the crystallographic quality of the seed and the morphology of the epitaxial growth surface. Heterojunction devices consist of glass/c-Si LT seed/ epi n+ Si:P/epi n- Si:P/intrinsic a-Si:H/p+ a-Si:H/ITO. Similar devices grown on electronically 'dead' n+ wafers have given Voc {approx}630 mV and {approx}8% efficiency with no light trapping features. Here we study the effects of the seed surface polish on epi-Si quality, how hydrogenation influences the device character, and the dominant junction transport physics.

  9. Stimulation of Cell Elongation by Tetraploidy in Hypocotyls of Dark-Grown Arabidopsis Seedlings.

    PubMed

    Narukawa, Hideki; Yokoyama, Ryusuke; Komaki, Shinichiro; Sugimoto, Keiko; Nishitani, Kazuhiko

    2015-01-01

    Plant size is largely determined by the size of individual cells. A number of studies showed a link between ploidy and cell size in land plants, but this link remains controversial. In this study, post-germination growth, which occurs entirely by cell elongation, was examined in diploid and autotetraploid hypocotyls of Arabidopsis thaliana (L.) Heynh. Final hypocotyl length was longer in tetraploid plants than in diploid plants, particularly when seedlings were grown in the dark. The longer hypocotyl in the tetraploid seedlings developed as a result of enhanced cell elongation rather than by an increase in cell number. DNA microarray analysis showed that genes involved in the transport of cuticle precursors were downregulated in a defined region of the tetraploid hypocotyl when compared to the diploid hypocotyl. Cuticle permeability, as assessed by toluidine-blue staining, and cuticular structure, as visualized by electron microscopy, were altered in tetraploid plants. Taken together, these data indicate that promotion of cell elongation is responsible for ploidy-dependent size determination in the Arabidopsis hypocotyl, and that this process is directly or indirectly related to cuticular function.

  10. Electron-cytochemical study of Ca2+ in cotyledon cells of soybean seedlings grown in microgravity

    NASA Technical Reports Server (NTRS)

    Nedukha, O.; Brown, C. S.; Kordyum, E.; Piastuch, W. C.; Guikema, J. A. (Principal Investigator)

    1999-01-01

    Microgravity and horizontal clinorotation are known to cause the rearrangement of the structural-functional organization of plant cells, leading to accelerated aging. Altered gravity conditions resulted in an increase in the droplets volume in cells and the destruction of chloroplast structure in Arabidopsis thaliana plants, an enhancement of cytosolic autophagaous processes, an increase in the respiration rate and a greater number of multimolecular forms of succinate- and malate dehydrogenases in cells of the Funaria hygrometrica protonema and Chlorella vulgaris, and changes in calcium balance of cells. Because ethylene is known to be involved in cell aging and microgravity appears to speed the process, and because soybean seedlings grown in space produce higher ethylene levels we asked: 1) does an acceleration of soybean cotyledon cell development and aging occur in microgravity? 2) what roles do Ca2+ ions and the enhanced ethylene level play in these events? Therefore, the goal of our investigation was to examine of the interaction of microgravity and ethylene on the localization of Ca2+ in cotyledon mesophyll of soybean seedlings.

  11. Neocartilage formation from mesenchymal stem cells grown in type II collagen-hyaluronan composite scaffolds.

    PubMed

    Yeh, Hsi-Yi; Lin, Ting-Yu; Lin, Chen-Huan; Yen, B Linju; Tsai, Ching-Lin; Hsu, Shan-Hui

    2013-01-01

    Three-dimensional (3D) collagen type II-hyaluronan (HA) composite scaffolds (CII-HA) which mimics the extracellular environment of natural cartilage were fabricated in this study. Rheological measurements demonstrated that the incorporation of HA increased the compression modulus of the scaffolds. An initial in vitro evaluation showed that scaffolds seeded with porcine chondrocytes formed cartilaginous-like tissue after 8 weeks, and HA functioned to promote the growth of chondrocytes into scaffolds. Placenta-derived multipotent cells (PDMC) and gingival fibroblasts (GF) were seeded on tissue culture polystyrene (TCPS), CII-HA films, and small intestinal submucosa (SIS) sheets for comparing their chondrogenesis differentiation potentials with those of adipose-derived adult stem cells (ADAS) and bone marrow-derived mesenchymal stem cells (BMSC). Among different cells, PDMC showed the greatest chondrogenic differentiation potential on both CII-HA films and SIS sheets upon TGF-β3 induction, followed by GF. This was evidenced by the up-regulation of chondrogenic genes (Sox9, aggrecan, and collagen type II), which was not observed for cells grown on TCPS. This finding suggested the essential role of substrate materials in the chondrogenic differentiation of PDMC and GF. Neocartilage formation was more obvious in both PDMC and GF cells plated on CII-HA composite scaffolds vs. 8-layer SIS at 28 days in vitro. Finally, implantation of PDMC/CII-HA constructs into NOD-SCID mice confirmed the formation of tissue-engineered cartilage in vivo.

  12. Aerobic Anoxygenic Phototrophic Bacteria

    PubMed Central

    Yurkov, Vladimir V.; Beatty, J. Thomas

    1998-01-01

    The aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. Although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthetically under anaerobic conditions. Aerobic anoxygenic phototrophic bacteria are classified in two marine (Erythrobacter and Roseobacter) and six freshwater (Acidiphilium, Erythromicrobium, Erythromonas, Porphyrobacter, Roseococcus, and Sandaracinobacter) genera, which phylogenetically belong to the α-1, α-3, and α-4 subclasses of the class Proteobacteria. Despite this phylogenetic information, the evolution and ancestry of their photosynthetic properties are unclear. We discuss several current proposals for the evolutionary origin of aerobic phototrophic bacteria. The closest phylogenetic relatives of aerobic phototrophic bacteria include facultatively anaerobic purple nonsulfur phototrophic bacteria. Since these two bacterial groups share many properties, yet have significant differences, we compare and contrast their physiology, with an emphasis on morphology and photosynthetic and other metabolic processes. PMID:9729607

  13. Differential Glioma-Associated Tumor Antigen Expression Profiles of Human Glioma Cells Grown in Hypoxia

    PubMed Central

    Ge, Lisheng; Cornforth, Andrew N.; Hoa, Neil T.; Delgado, Christina; Chiou, Shiun Kwei; Zhou, Yi Hong; Jadus, Martin R.

    2012-01-01

    Human U251 and D54 glioma cells were tested for expression of 25 glioma-associated tumor antigen precursor proteins (TAPP) under hypoxic (1% O2) or normoxic (21% O2) conditions. Hypoxic glioma cell lines increased their mRNA expression for nine TAPP (Aim2, Art-4, EphA2, EZH2, Fosl1, PTH-rP, Sox 11, Whsc2 and YKL-40), as assessed by quantitative reverse transcriptase real-time/polymerase chain reaction (qRT-PCR). Increased differences with three hypoxic-induced TAPP: EZH2, Whsc2 and YKL-40 were shown at the protein levels by fluorescent antibody staining and quantitative electrophoretic analysis. Two TAPP (MRP3 and Trp1) were down-regulated by hypoxia in glioma cell lines. Growing the glioma cells under hypoxia for 13 days, followed by returning them back to normoxic conditions for 7 days, and restored the original normoxic TAPP profile. Thus, hypoxia was an environmental factor that stimulated the transient expression of these antigens. Intracranial xenografts grown in nude mice derived from U251 cells that had been cultured under neurosphere stem cell conditions showed increased expression of Whsc2 or YKL-40, demonstrating that these in vitro properties of glioma also occur in vivo. Whsc2-specific cytotoxic T lymphocytes killed the hypoxic U251 glioma cells better than normoxic glioma cells. The antigens expressed by hypoxic tumor cells may be a better source of starting tumor material for loading dendritic cells for novel immunotherapy of glioma using tumor-associated antigens. PMID:22957023

  14. Differential glioma-associated tumor antigen expression profiles of human glioma cells grown in hypoxia.

    PubMed

    Ge, Lisheng; Cornforth, Andrew N; Hoa, Neil T; Delgado, Christina; Chiou, Shiun Kwei; Zhou, Yi Hong; Jadus, Martin R

    2012-01-01

    Human U251 and D54 glioma cells were tested for expression of 25 glioma-associated tumor antigen precursor proteins (TAPP) under hypoxic (1% O(2)) or normoxic (21% O(2)) conditions. Hypoxic glioma cell lines increased their mRNA expression for nine TAPP (Aim2, Art-4, EphA2, EZH2, Fosl1, PTH-rP, Sox 11, Whsc2 and YKL-40), as assessed by quantitative reverse transcriptase real-time/polymerase chain reaction (qRT-PCR). Increased differences with three hypoxic-induced TAPP: EZH2, Whsc2 and YKL-40 were shown at the protein levels by fluorescent antibody staining and quantitative electrophoretic analysis. Two TAPP (MRP3 and Trp1) were down-regulated by hypoxia in glioma cell lines. Growing the glioma cells under hypoxia for 13 days, followed by returning them back to normoxic conditions for 7 days, and restored the original normoxic TAPP profile. Thus, hypoxia was an environmental factor that stimulated the transient expression of these antigens. Intracranial xenografts grown in nude mice derived from U251 cells that had been cultured under neurosphere stem cell conditions showed increased expression of Whsc2 or YKL-40, demonstrating that these in vitro properties of glioma also occur in vivo. Whsc2-specific cytotoxic T lymphocytes killed the hypoxic U251 glioma cells better than normoxic glioma cells. The antigens expressed by hypoxic tumor cells may be a better source of starting tumor material for loading dendritic cells for novel immunotherapy of glioma using tumor-associated antigens.

  15. In situ aerobic cometabolism of chlorinated solvents: a review.

    PubMed

    Frascari, Dario; Zanaroli, Giulio; Danko, Anthony S

    2015-01-01

    The possible approaches for in situ aerobic cometabolism of aquifers and vadose zones contaminated by chlorinated solvents are critically evaluated. Bioaugmentation of resting-cells previously grown in a fermenter and in-well addition of oxygen and growth substrate appear to be the most promising approaches for aquifer bioremediation. Other solutions involving the sparging of air lead to satisfactory pollutant removals, but must be integrated by the extraction and subsequent treatment of vapors to avoid the dispersion of volatile chlorinated solvents in the atmosphere. Cometabolic bioventing is the only possible approach for the aerobic cometabolic bioremediation of the vadose zone. The examined studies indicate that in situ aerobic cometabolism leads to the biodegradation of a wide range of chlorinated solvents within remediation times that vary between 1 and 17 months. Numerous studies include a simulation of the experimental field data. The modeling of the process attained a high reliability, and represents a crucial tool for the elaboration of field data obtained in pilot tests and for the design of the full-scale systems. Further research is needed to attain higher concentrations of chlorinated solvent degrading microbes and more reliable cost estimates. Lastly, a procedure for the design of full-scale in situ aerobic cometabolic bioremediation processes is proposed.

  16. Label-free optical detection of cells grown in 3D silicon microstructures.

    PubMed

    Merlo, Sabina; Carpignano, Francesca; Silva, Gloria; Aredia, Francesca; Scovassi, A Ivana; Mazzini, Giuliano; Surdo, Salvatore; Barillaro, Giuseppe

    2013-08-21

    We demonstrate high aspect-ratio photonic crystals that could serve as three-dimensional (3D) microincubators for cell culture and also provide label-free optical detection of the cells. The investigated microstructures, fabricated by electrochemical micromachining of standard silicon wafers, consist of periodic arrays of silicon walls separated by narrow deeply etched air-gaps (50 μm high and 5 μm wide) and feature the typical spectral properties of photonic crystals in the wavelength range 1.0-1.7 μm: their spectral reflectivity is characterized by wavelength regions where reflectivity is high (photonic bandgaps), separated by narrow wavelength regions where reflectivity is very low. In this work, we show that the presence of cells, grown inside the gaps, strongly affects light propagation across the photonic crystal and, therefore, its spectral reflectivity. Exploiting a label-free optical detection method, based on a fiberoptic setup, we are able to probe the extension of cells adherent to the vertical silicon walls with a non-invasive direct testing. In particular, the intensity ratio at two wavelengths is the experimental parameter that can be well correlated to the cell spreading on the silicon wall inside the gaps.

  17. Enterotoxin production by Vibrio cholerae and Vibrio mimicus grown in continuous culture with microbial cell recycle.

    PubMed Central

    Spira, W M; Fedorka-Cray, P J

    1983-01-01

    We have examined the effect of complete cell recycle on the production of cholera toxin (CT) by Vibrio cholerae and CT-like toxin by Vibrio mimicus in continuous culture fermentations. Complete cell recycle was obtained by filtering culture fluids through Amicon hollow fibers with an exclusion limit of 100,000 daltons (H1P100-20) and returning the concentrated cell slurry to the fermentor. A single 1-liter laboratory fermentor system modified with this recycle loop was capable of producing over 20 liters of cell-free culture filtrate per day. Toxin production in this system was compared with yields obtained in traditional continuous cultures and in shake flask cultures. Yields of CT from V. cholerae 569B in the recycle fermentor were highest at the highest dilution rate employed (1.0 vol/vol per h). The use of complete cell recycle dramatically increased yields over those obtained in continuous culture and equaled those obtained in shake flasks. The concentration of CT in the filtrate was slightly less than half of that measured in culture fluids sampled at the same time. Similarly, V. mimicus 61892 grown in the presence of 50 micrograms of lincomycin per ml produced 280 ng of CT per ml in the recycle fermentor, compared with 210 ng/ml in shake flasks under optimal conditions. The sterile filtrate from this fermentation contained 110 ng/ml. PMID:6357081

  18. Inhibition of Aerobic Glycolysis Represses Akt/mTOR/HIF-1α Axis and Restores Tamoxifen Sensitivity in Antiestrogen-Resistant Breast Cancer Cells.

    PubMed

    Woo, Yu Mi; Shin, Yubin; Lee, Eun Ji; Lee, Sunyoung; Jeong, Seung Hun; Kong, Hyun Kyung; Park, Eun Young; Kim, Hyoung Kyu; Han, Jin; Chang, Minsun; Park, Jong-Hoon

    2015-01-01

    Tamoxifen resistance is often observed in the majority of estrogen receptor-positive breast cancers and it remains as a serious clinical problem in breast cancer management. Increased aerobic glycolysis has been proposed as one of the mechanisms for acquired resistance to chemotherapeutic agents in breast cancer cells such as adriamycin. Herein, we report that the glycolysis rates in LCC2 and LCC9--tamoxifen-resistant human breast cancer cell lines derived from MCF7--are higher than those in MCF7S, which is the parent MCF7 subline. Inhibition of key glycolytic enzyme such as hexokinase-2 resulted in cell growth retardation at higher degree in LCC2 and LCC9 than that in MCF7S. This implies that increased aerobic glycolysis even under O2-rich conditions, a phenomenon known as the Warburg effect, is closely associated with tamoxifen resistance. We found that HIF-1α is activated via an Akt/mTOR signaling pathway in LCC2 and LCC9 cells without hypoxic condition. Importantly, specific inhibition of hexokinase-2 suppressed the activity of Akt/mTOR/HIF-1α axis in LCC2 and LCC9 cells. In addition, the phosphorylated AMPK which is a negative regulator of mTOR was decreased in LCC2 and LCC9 cells compared to MCF7S. Interestingly, either the inhibition of mTOR activity or increase in AMPK activity induced a reduction in lactate accumulation and cell survival in the LCC2 and LCC9 cells. Taken together, our data provide evidence that development of tamoxifen resistance may be driven by HIF-1α hyperactivation via modulation of Akt/mTOR and/or AMPK signaling pathways. Therefore, we suggest that the HIF-1α hyperactivation is a critical marker of increased aerobic glycolysis in accordance with tamoxifen resistance and thus restoration of aerobic glycolysis may be novel therapeutic target for treatment of tamoxifen-resistant breast cancer.

  19. Die aerobe Glykolyse der Tumorzelle

    NASA Astrophysics Data System (ADS)

    Schneider, Friedhelm

    1981-01-01

    A high aerobic glycolysis (aerobic lactate production) is the most significant feature of the energy metabolism of rapidly growing tumor cells. Several mechanisms, which may be different in different cell lines, seem to be involved in this characteristic of energy metabolism of the tumor cell. Changes in the cell membrane leading to increased uptake and utilization of glucose, a high level of fetal types of isoenzymes, a decreased number of mitochondria and a reduced capacity to metabolize pyruvate are some factors which must be taken into consideration. It is not possible to favour one of them at the present time.

  20. Proof of Concept to Isolate and Culture Primary Muscle Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-hold Diving

    DTIC Science & Technology

    2012-09-30

    Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-hold Diving...To isolate and culture primary muscle cells from the swimming muscles of northern elephant seals . OBJECTIVES Objective 1. To test the...Proof of Concept to Isolate and Culture Primary Muscle Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under

  1. An NMR probe for the study of aerobic suspensions of cells and organelles

    SciTech Connect

    Balaban, R.S.; Gadian, D.G.; Radda, G.K.; Wong, G.G.

    1981-09-15

    The construction of an NMR probe and cell chamber with good mixing, pH buffering, and oxygenation characteristics, which can be used for relatively dilute cell and organelle suspension is described. The /sup 31/P NMR spectra of acceptable signal-to-noise ratios are obtained from approximately 200 mg (protein) of tissues, and kinetic studies of mitochondrial oxidative phosphorylation are demonstrated. Representative spectra from rabbit kidney cortical tubules and rabbit kidney cortical mitochondria are presented.

  2. GM-CSF Grown Bone Marrow Derived Cells Are Composed of Phenotypically Different Dendritic Cells and Macrophages

    PubMed Central

    Na, Yi Rang; Jung, Daun; Gu, Gyo Jeong; Seok, Seung Hyeok

    2016-01-01

    Granulocyte-macrophage colony stimulating factor (GM-CSF) has a role in inducing emergency hematopoiesis upon exposure to inflammatory stimuli. Although GM-CSF generated murine bone marrow derived cells have been widely used as macrophages or dendritic cells in research, the exact characteristics of each cell population have not yet been defined. Here we discriminated GM-CSF grown bone marrow derived macrophages (GM-BMMs) from dendritic cells (GM-BMDCs) in several criteria. After C57BL/6J mice bone marrow cell culture for 7 days with GM-CSF supplementation, two main populations were observed in the attached cells based on MHCII and F4/80 marker expressions. GM-BMMs had MHCIIlowF4/80high as well as CD11c+CD11bhighCD80−CD64+MerTK+ phenotypes. In contrast, GM-BMDCs had MHCIIhighF4/80low and CD11chighCD8α− CD11b+CD80+CD64−MerTKlow phenotypes. Interestingly, the GM-BMM population increased but GM-BMDCs decreased in a GM-CSF dose-dependent manner. Functionally, GM-BMMs showed extremely high phagocytic abilities and produced higher IL-10 upon LPS stimulation. GM-BMDCs, however, could not phagocytose as well, but were efficient at producing TNFα, IL-1β, IL-12p70 and IL-6 as well as inducing T cell proliferation. Finally, whole transcriptome analysis revealed that GM-BMMs and GM-BMDCs are overlap with in vivo resident macrophages and dendritic cells, respectively. Taken together, our study shows the heterogeneicity of GM-CSF derived cell populations, and specifically characterizes GM-CSF derived macrophages compared to dendritic cells. PMID:27788572

  3. Radial junction amorphous silicon solar cells on PECVD-grown silicon nanowires.

    PubMed

    Yu, Linwei; O'Donnell, Benedict; Foldyna, Martin; Roca i Cabarrocas, Pere

    2012-05-17

    Constructing radial junction hydrogenated amorphous silicon (a-Si:H) solar cells on top of silicon nanowires (SiNWs) represents a promising approach towards high performance and cost-effective thin film photovoltaics. We here develop an all-in situ strategy to grow SiNWs, via a vapour-liquid-solid (VLS) mechanism on top of ZnO-coated glass substrate, in a plasma-enhanced chemical vapour deposition (PECVD) reactor. Controlling the distribution of indium catalyst drops allows us to tailor the as-grown SiNW arrays into suitable size and density, which in turn results in both a sufficient light trapping effect and a suitable arrangement allowing for conformal coverage of SiNWs by subsequent a-Si:H layers. We then demonstrate the fabrication of radial junction solar cells and carry on a parametric study designed to shed light on the absorption and quantum efficiency response, as functions of the intrinsic a-Si:H layer thickness and the density of SiNWs. These results lay a solid foundation for future structural optimization and performance ramp-up of the radial junction thin film a-Si:H photovoltaics.

  4. Epoxidation of Short-Chain Alkenes by Resting-Cell Suspensions of Propane-Grown Bacteria

    PubMed Central

    Hou, Ching T.; Patel, Ramesh; Laskin, Allen I.; Barnabe, Nancy; Barist, Irene

    1983-01-01

    Sixteen new cultures of propane-utilizing bacteria were isolated from lake water from Warinanco Park, Linden, N.J. and from lake and soil samples from Bayway Refinery, Linden, N.J. In addition, 19 known cultures obtained from culture collections were also found to be able to grow on propane as the sole carbon and energy source. In addition to their ability to oxidize n-alkanes, resting-cell suspensions of both new cultures and known cultures grown on propane oxidize short-chain alkenes to their corresponding 1,2-epoxides. Among the substrate alkenes, propylene was oxidized at the highest rate. In contrast to the case with methylotrophic bacteria, the product epoxides are further metabolized. Propane and other gaseous n-alkanes inhibit the epoxidation of propylene. The optimum conditions for in vivo epoxidation are described. Results from inhibition studies indicate that a propane monooxygenase system catalyzes both the epoxidation and hydroxylation reactions. Experiments with cell-free extracts show that both hydroxylation and epoxidation activities are located in the soluble fraction obtained after 80,000 × g centrifugation. PMID:16346338

  5. Berry extracts exert different antiproliferative effects against cervical and colon cancer cells grown in vitro.

    PubMed

    McDougall, Gordon J; Ross, Heather A; Ikeji, Magnus; Stewart, Derek

    2008-05-14

    Polyphenol-rich berry extracts were screened for their antiproliferative effectiveness using human cervical cancer (HeLa) cells grown in microtiter plates. Rowan berry, raspberry, lingonberry, cloudberry, arctic bramble, and strawberry extracts were effective but blueberry, sea buckthorn, and pomegranate extracts were considerably less effective. The most effective extracts (strawberry > arctic bramble > cloudberry > lingonberry) gave EC 50 values in the range of 25-40 microg/(mL of phenols). These extracts were also effective against human colon cancer (CaCo-2) cells, which were generally more sensitive at low concentrations but conversely less sensitive at higher concentrations. The strawberry, cloudberry, arctic bramble, and the raspberry extracts share common polyphenol constituents, especially the ellagitannins, which have been shown to be effective antiproliferative agents. However, the components underlying the effectiveness of the lingonberry extracts are not known. The lingonberry extracts were fractionated into anthocyanin-rich and tannin-rich fractions by chromatography on Sephadex LH-20. The anthocyanin-rich fraction was considerably less effective than the original extract, whereas the antiproliferative activity was retained in the tannin-rich fraction. The polyphenolic composition of the lingonberry extract was assessed by liquid chromatography-mass spectrometry and was similar to previous reports. The tannin-rich fraction was almost entirely composed of procyanidins of linkage type A and B. Therefore, the antiproliferative activity of lingonberry was caused predominantly by procyanidins.

  6. GaSb thermophotovoltaic cells grown on GaAs by molecular beam epitaxy using interfacial misfit arrays

    SciTech Connect

    Juang, Bor-Chau Laghumavarapu, Ramesh B.; Foggo, Brandon J.; Lin, Andrew; Simmonds, Paul J.; Liang, Baolai; Huffaker, Diana L.

    2015-03-16

    There exists a long-term need for foreign substrates on which to grow GaSb-based optoelectronic devices. We address this need by using interfacial misfit arrays to grow GaSb-based thermophotovoltaic cells directly on GaAs (001) substrates and demonstrate promising performance. We compare these cells to control devices grown on GaSb substrates to assess device properties and material quality. The room temperature dark current densities show similar characteristics for both cells on GaAs and on GaSb. Under solar simulation the cells on GaAs exhibit an open-circuit voltage of 0.121 V and a short-circuit current density of 15.5 mA/cm{sup 2}. In addition, the cells on GaAs substrates maintain 10% difference in spectral response to those of the control cells over a large range of wavelengths. While the cells on GaSb substrates in general offer better performance than the cells on GaAs substrates, the cost-savings and scalability offered by GaAs substrates could potentially outweigh the reduction in performance. By further optimizing GaSb buffer growth on GaAs substrates, Sb-based compound semiconductors grown on GaAs substrates with similar performance to devices grown directly on GaSb substrates could be realized.

  7. Enrichment of anodic biofilm inoculated with anaerobic or aerobic sludge in single chambered air-cathode microbial fuel cells.

    PubMed

    Gao, Chongyang; Wang, Aijie; Wu, Wei-Min; Yin, Yalin; Zhao, Yang-Guo

    2014-09-01

    Aerobic sludge after anaerobic pretreatment and anaerobic sludge were separately used as inoculum to start up air-cathode single-chamber MFCs. Aerobic sludge-inoculated MFCs arrived at 0.27 V with a maximum power density of 5.79 W m(-3), while anaerobic sludge-inoculated MFCs reached 0.21 V with 3.66 W m(-3). Microbial analysis with DGGE profiling and high-throughput sequencing indicated that aerobic sludge contained more diverse bacterial populations than anaerobic sludge. Nitrospira species dominated in aerobic sludge, while anaerobic sludge was dominated by Desulfurella and Acidithiobacillus species. Microbial community structure and composition in anodic biofilms enriched, respectively from aerobic and anaerobic sludges tended gradually to be similar. Potentially exoelectrogenic Geobacter and Anaeromusa species, biofilm-forming Zoogloea and Acinetobacter species were abundant in both anodic biofilms. This study indicated that aerobic sludge performed better for MFCs startup, and the enrichment of anodic microbial consortium with different inocula but same substrate resulted in uniformity of functional microbial communities.

  8. ENDIVE PLANTLETS FROM FREELY SUSPENDED CELLS AND CELL GROUPS GROWN IN VITRO.

    PubMed

    VASIL, I K; HILDEBRANDT, A C; RIKER, A J

    1964-10-02

    Callus tissue derived from mature embryos of the endive, Cichorium endivia Linn. (family Compositae) grows and develops chlorophyll on a completely defined nutrient medium. The tissue breaks up into a thick suspentsion of cells and cell groups in a liquid medium kept in a flask on a shaker. Gradually, many small round masses of tissue, designated here as embryoids, are formed; these become differentiated and organized to form numnerous small plantlets having typical curled and fringed green leaves and roots.

  9. Pectic Polysaccharide Breakdown of Cell Walls in Cucumber Roots Grown with Calcium Starvation 1

    PubMed Central

    Konno, Haruyoshi; Yamaya, Tomoyuki; Yamasaki, Yoshiki; Matsumoto, Hideaki

    1984-01-01

    Pectic polysaccharides from the roots of cucumber (Cucumis sativus L.) grown in liquid culture medium with or without calcium (1 mm CaCl2) were studied after extraction successively by hot water and Na hexametaphosphate solution. The Ca2+ starvation-treatment caused a striking reduction in content of extracted pectic polysaccharide; from an equivalent weight of cell walls, only 33.1% of the control level was extracted from root cell walls of plants cultured under Ca2+ deficiency. The extracted pectic polysaccharides were fractionated into neutral and acidic polymers by a DEAE-Sephadex column. The acidic polymers, which represented more than 76% of the yield, appeared to be a major fraction of extracted pectic polysaccharides. The changes of molecular size and glycosyl residue composition of this fraction were compared for the control and Ca2+-deprived samples. The results indicate that Ca2+ deficiency caused structural changes which could involve both branching pattern and extent of contiguous galacturonosyl units in the water-solubilized pectic polysaccharides. Ca2+ starvation also led to a notable decrease in molecular size of the hexametaphosphate-solubilized polysaccharides and, to a lesser extent, of the water-solubilized fraction as well. In addition, polygalacturonase activity in tissue homogenates increased remarkably with the Ca2+ deficiency, whereas β-galactosidase activity did not undergo a change. Thus, it appears that one major effect of Ca2+ deprivation was to stimulate polygalacturonase activity, an effect which could be involved in the control of the breakdown of pectic polysaccharides in the cell walls. PMID:16663897

  10. Antrodia camphorata Grown on Germinated Brown Rice Suppresses Melanoma Cell Proliferation by Inducing Apoptosis and Cell Differentiation and Tumor Growth

    PubMed Central

    Song, Minjung; Park, Dong Ki; Park, Hye-Jin

    2013-01-01

    Antrodia camphorata grown on germinated brown rice (CBR) was prepared to suppress melanoma development. CBR extracts were divided into hexane, EtOAc, BuOH, and water fractions. Among all the fractions, EtOAc fraction showed the best suppressive effect on B16F10 melanoma cell proliferation by CCK-8 assay. It also showed the increased cell death and the changed cellular morphology after CBR treatment. Annexin V-FITC/PI, flow cytometry, and western blotting were performed to elucidate anticancer activity of CBR. The results showed that CBR induced p53-mediated apoptotic cell death of B16F10. CBR EtOAc treatment increased melanin content and melanogenesis-related proteins of MITF and TRP-1 expressions, which supports its anticancer activity. Its potential as an anticancer agent was further investigated in tumor-xenografted mouse model. In melanoma-xenografted mouse model, melanoma tumor growth was significantly suppressed under CBR EtOAc fraction treatment. HPLC analysis of CBR extract showed peak of adenosine. In conclusion, CBR extracts notably inhibited B16F10 melanoma cell proliferation through the p53-mediated apoptosis induction and increased melanogenesis. These findings suggest that CBR EtOAc fraction can act as an effective anticancer agent to treat melanoma. PMID:23533475

  11. A Combination of Schwann-Cell Grafts and Aerobic Exercise Enhances Sciatic Nerve Regeneration

    PubMed Central

    Souto, Allana; Oliveira, Júlia Teixeira; de Lima, Silmara; Tonda-Turo, Chiara; Marques, Suelen Adriani; de Almeida, Fernanda Martins; Martinez, Ana Maria Blanco

    2014-01-01

    Background Despite the regenerative potential of the peripheral nervous system, severe nerve lesions lead to loss of target-organ innervation, making complete functional recovery a challenge. Few studies have given attention to combining different approaches in order to accelerate the regenerative process. Objective Test the effectiveness of combining Schwann-cells transplantation into a biodegradable conduit, with treadmill training as a therapeutic strategy to improve the outcome of repair after mouse nerve injury. Methods Sciatic nerve transection was performed in adult C57BL/6 mice; the proximal and distal stumps of the nerve were sutured into the conduit. Four groups were analyzed: acellular grafts (DMEM group), Schwann cell grafts (3×105/2 µL; SC group), treadmill training (TMT group), and treadmill training and Schwann cell grafts (TMT + SC group). Locomotor function was assessed weekly by Sciatic Function Index and Global Mobility Test. Animals were anesthetized after eight weeks and dissected for morphological analysis. Results Combined therapies improved nerve regeneration, and increased the number of myelinated fibers and myelin area compared to the DMEM group. Motor recovery was accelerated in the TMT + SC group, which showed significantly better values in sciatic function index and in global mobility test than in the other groups. The TMT + SC group showed increased levels of trophic-factor expression compared to DMEM, contributing to the better functional outcome observed in the former group. The number of neurons in L4 segments was significantly higher in the SC and TMT + SC groups when compared to DMEM group. Counts of dorsal root ganglion sensory neurons revealed that TMT group had a significant increased number of neurons compared to DMEM group, while the SC and TMT + SC groups had a slight but not significant increase in the total number of motor neurons. Conclusion These data provide evidence that this combination of therapeutic strategies can

  12. Activation of the FGFR1 signalling pathway by the Epstein-Barr virus-encoded LMP1 promotes aerobic glycolysis and transformation of human nasopharyngeal epithelial cells.

    PubMed

    Lo, Angela Kwok-Fung; Dawson, Christopher W; Young, Lawrence S; Ko, Chuen-Wai; Hau, Pok-Man; Lo, Kwok-Wai

    2015-10-01

    Non-keratinizing nasopharyngeal carcinoma (NPC) is closely associated with Epstein-Barr virus (EBV) infection. The EBV-encoded latent membrane protein 1 (LMP1) is believed to play an important role in NPC pathogenesis by virtue of its ability to activate multiple cell signalling pathways which collectively promote cell proliferation, transformation, angiogenesis, and invasiveness, as well as modulation of energy metabolism. In this study, we report that LMP1 increases cellular uptake of glucose and glutamine, enhances LDHA activity and lactate production, but reduces pyruvate kinase activity and pyruvate concentrations. LMP1 also increases the phosphorylation of PKM2, LDHA, and FGFR1, as well as the expression of PDHK1, FGFR1, c-Myc, and HIF-1α, regardless of oxygen availability. Collectively, these findings suggest that LMP1 promotes aerobic glycolysis. With respect to FGFR1 signalling, LMP1 not only increases FGFR1 expression, but also up-regulates FGF2, leading to constitutive activation of the FGFR1 signalling pathway. Furthermore, two inhibitors of FGFR1 (PD161570 and SU5402) attenuate LMP1-mediated aerobic glycolysis, cellular transformation (proliferation and anchorage-independent growth), cell migration, and invasion in nasopharyngeal epithelial cells, identifying FGFR1 signalling as a key pathway in LMP1-mediated growth transformation. Immunohistochemical staining revealed that high levels of phosphorylated FGFR1 are common in primary NPC specimens and that this correlated with the expression of LMP1. In addition, FGFR1 inhibitors suppress cell proliferation and anchorage-independent growth of NPC cells. Our current findings demonstrate that LMP1-mediated FGFR1 activation contributes to aerobic glycolysis and transformation of epithelial cells, thereby implicating FGF2/FGFR1 signalling activation in the EBV-driven pathogenesis of NPC.

  13. Aerobic training modulates T cell activation in elderly women with knee osteoarthritis.

    PubMed

    Gomes, W F; Lacerda, A C R; Brito-Melo, G E A; Fonseca, S F; Rocha-Vieira, E; Leopoldino, A A O; Amorim, M R; Mendonça, V A

    2016-01-01

    Osteoarthritis of the knee (kOA) is a disease that mainly affects the elderly and can lead to major physical and functional limitations. However, the specific effects of walking, particularly on the immune system, are unknown. Therefore, this study aimed to analyze the effect of 12 weeks of walking (3×/week) on the leukocyte profile and quality of life (QL) of elderly women with kOA. Sixteen women (age: 67±4 years, body mass index: 28.07±4.16 kg/m2) participated in a walking program. The variables were assessed before and after 12 weeks of training with a progressively longer duration (30-55 min) and higher intensity (72-82% of HRmax determined using a graded incremental treadmill test). The QL was assessed using the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36), and blood samples were collected for analysis with a cell counter and the San Fac flow cytometer. Walking training resulted in a 47% enhancement of the self-reported QL (P<0.05) and a 21% increase in the VO2max (P<0.0001) in elderly women with kOA. Furthermore, there was a reduction in CD4+ cells (pre=46.59±7%, post=44.58±9%, P=0.0189) and a higher fluorescence intensity for CD18+CD4+ (pre=45.30±10, post=64.27±33, P=0.0256) and CD18+CD8+ (pre=64.2±27, post=85.02±35, P=0.0130). In conclusion, the walking program stimulated leukocyte production, which may be related to the immunomodulatory effect of exercise. Walking also led to improvements in the QL and physical performance in elderly women with kOA.

  14. Aerobic training modulates T cell activation in elderly women with knee osteoarthritis

    PubMed Central

    Gomes, W.F.; Lacerda, A.C.R.; Brito-Melo, G.E.A.; Fonseca, S.F.; Rocha-Vieira, E.; Leopoldino, A.A.O.; Amorim, M.R.; Mendonça, V.A.

    2016-01-01

    Osteoarthritis of the knee (kOA) is a disease that mainly affects the elderly and can lead to major physical and functional limitations. However, the specific effects of walking, particularly on the immune system, are unknown. Therefore, this study aimed to analyze the effect of 12 weeks of walking (3×/week) on the leukocyte profile and quality of life (QL) of elderly women with kOA. Sixteen women (age: 67±4 years, body mass index: 28.07±4.16 kg/m2) participated in a walking program. The variables were assessed before and after 12 weeks of training with a progressively longer duration (30–55 min) and higher intensity (72–82% of HRmax determined using a graded incremental treadmill test). The QL was assessed using the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36), and blood samples were collected for analysis with a cell counter and the San Fac flow cytometer. Walking training resulted in a 47% enhancement of the self-reported QL (P<0.05) and a 21% increase in the VO2max (P<0.0001) in elderly women with kOA. Furthermore, there was a reduction in CD4+ cells (pre=46.59±7%, post=44.58±9%, P=0.0189) and a higher fluorescence intensity for CD18+CD4+ (pre=45.30±10, post=64.27±33, P=0.0256) and CD18+CD8+ (pre=64.2±27, post=85.02±35, P=0.0130). In conclusion, the walking program stimulated leukocyte production, which may be related to the immunomodulatory effect of exercise. Walking also led to improvements in the QL and physical performance in elderly women with kOA. PMID:27828665

  15. Radiosensitivity of different human tumor cells lines grown as multicellular spheroids determined from growth curves and survival data

    SciTech Connect

    Schwachoefer, J.H.C.; Crooijmans, R.P.; van Gasteren, J.J.; Hoogenhout, J.; Jerusalem, C.R.; Kal, H.B.; Theeuwes, A.G. )

    1989-11-01

    Five human tumor cell lines were grown as multicellular tumor spheroids (MTS) to determine whether multicellular tumor spheroids derived from different types of tumors would show tumor-type dependent differences in response to single-dose irradiation, and whether these differences paralleled clinical behavior. Multicellular tumor spheroids of two neuroblastoma, one lung adenocarcinoma, one melanoma, and a squamous cell carcinoma of the oral tongue, were studied in terms of growth delay, calculated cell survival, and spheroid control dose50 (SCD50). Growth delay and cell survival analysis for the tumor cell lines showed sensitivities that correlated well with clinical behavior of the tumor types of origin. Similar to other studies on melanoma multicellular tumor spheroids our spheroid control dose50 results for the melanoma cell line deviated from the general pattern of sensitivity. This might be due to the location of surviving cells, which prohibits proliferation of surviving cells and hence growth of melanoma multicellular tumor spheroids. This study demonstrates that radiosensitivity of human tumor cell lines can be evaluated in terms of growth delay, calculated cell survival, and spheroid control dose50 when grown as multicellular tumor spheroids. The sensitivity established from these evaluations parallels clinical behavior, thus offering a unique tool for the in vitro analysis of human tumor radiosensitivity.

  16. Optimizing aerobic conversion of glycerol to 3-hydroxypropionaldehyde.

    PubMed Central

    Slininger, P J; Bothast, R J

    1985-01-01

    When cells of Klebsiella pneumoniae NRRL B-199 (ATCC 8724) were grown aerobically on a rich glycerol medium and then suspended in buffer supplemented with semicarbazide and glycerol, aerobic conversion of glycerol to 3-hydroxypropionaldehyde (3-HPA) ensued. Depending on conditions, 0.38 to 0.67 g of 3-HPA were formed per gram of glycerol consumed. This means that up to 83.8% of the carbon invested as glycerol could potentially be recovered as the target product, 3-HPA. Production of 3-HPA was sensitive to the age of cells harvested for resuspension and was nonexistent if cells were cultivated on glucose instead of glycerol as the sole carbon source. Compared with 24- and 72-h cells, 48-h cells produced 3-HPA at the highest rate and with the greatest yield. The cell biomass concentration present during the fermentation was never particularly critical to the 3-HPA yield, but initial fermentation rates and 3-HPA accumulation displayed a linear dependence on biomass concentration that faded when biomass exceeded 3 g/liter. Fermentation performance was a function of temperature, and an optimum initial specific 3-HPA productivity occurred at 32 degrees C, although the overall 3-HPA yield increased continuously within the 25 to 37 degrees C range studied. The pH optimum based on fermentation rate was different from that based on overall yield; 8 versus 7, respectively. Initial glycerol concentrations in the 20 to 50 g/liter range optimized initial 3-HPA productivity and yield. PMID:3911907

  17. Proline biosynthesis augments tumor cell growth and aerobic glycolysis: involvement of pyridine nucleotides.

    PubMed

    Liu, Wei; Hancock, Chad N; Fischer, Joseph W; Harman, Meredith; Phang, James M

    2015-11-24

    The metabolism of the nonessential amino acid proline contributes to tumor metabolic reprogramming. Previously we showed that MYC increases proline biosynthesis (PB) from glutamine. Here we show MYC increases the expression of the enzymes in PB at both protein and mRNA levels. Blockade of PB decreases tumor cell growth and energy production. Addition of Δ(1)-pyrroline-5-carboxylate (P5C) or proline reverses the effects of P5C synthase knockdown but not P5C reductases knockdown. Importantly, the reversal effect of proline was blocked by concomitant proline dehydrogenase/oxidase (PRODH/POX) knockdown. These findings suggest that the important regulatory contribution of PB to tumor growth derives from metabolic cycling between proline and P5C rather than product proline or intermediate P5C. We further document the critical role of PB in maintaining pyridine nucleotide levels by connecting the proline cycle to glycolysis and to the oxidative arm of the pentose phosphate pathway. These findings establish a novel function of PB in tumorigenesis, linking the reprogramming of glucose, glutamine and pyridine nucleotides, and may provide a novel target for antitumor therapy.

  18. In human alloreactive CD4⁺ T-cells, dichloroacetate inhibits aerobic glycolysis, induces apoptosis and favors differentiation towards the regulatory T-cell subset instead of effector T-cell subsets.

    PubMed

    Eleftheriadis, Theodoros; Sounidaki, Maria; Pissas, Georgios; Antoniadi, Georgia; Liakopoulos, Vassilios; Stefanidis, Ioannis

    2016-04-01

    Although kidney transplantation is the best therapy for end-stage renal disease, rejection remains a concern, and currently available immunosuppressive agents contribute to morbidity and mortality. Thus, novel immunosuppressive drugs are required. Dichloroacetate (DCA) is already used in the treatment of congenital lactic acidosis and characterized by limited toxicity. As DCA inhibits aerobic glycolysis, which is a prerequisite for CD4+ T-cell proliferation and differentiation into effector T-cells, its possible immunosuppressive role in mixed lymphocyte reaction (MLR), a model of alloreactivity, was investigated. Glucose and lactate concentrations were measured in the supernatants, and cell proliferation was assessed immunoenzymatically. CD4+ T‑cells were then isolated from the MLRs and the expression of cleaved caspase‑3, various enzymes involved in glycolysis, and the signature transcription factors of CD4+ T‑cell subsets were evaluated by western blotting. In MLRs, DCA decreased glucose consumption and aerobic glycolysis, while it exerted a negligible effect on cell proliferation. In CD4+ T‑cells, DCA induced apoptosis, and decreased the expression of glucose trasporter‑1, hexokinase II, lactate dehydrogenase‑A and phosphorylated pyruvate dehydrogenase, while it increased total pyruvate dehydrogenase. In addition, DCA increased the expression of transcription factor forkhead box P3, whereas it decreased the expression of T‑box transcription factor TBX21, trans‑acting T-cell-specific transcription factor GATA‑3 and retinoic acid receptor related orphan receptor‑γt. In conclusion, in alloreactive CD4+ T‑cells, DCA inhibits aerobic glycolysis, induces apoptosis and favors differentiation towards the regulatory T‑cell subset. These characteristics render it a promising immunosuppressive agent in the field of transplantation.

  19. Performance improvement for epitaxially grown SiGe on Si solar cell using a compositionally graded SiGe base

    NASA Astrophysics Data System (ADS)

    Li, Dun; Zhao, Xin; Wang, Li; Conrad, Brianna; Soeriyadi, Anastasia; Lochtefeld, Anthony; Gerger, Andrew; Perez-Wurfl, Ivan; Barnett, Allen

    2016-12-01

    Silicon germanium (SiGe) is a material with high mobility and relatively low bandgap making it an attractive candidate for the bottom subcell in a III-V tandem solar cell grown on silicon (Si) substrate. This paper reports on the performance improvement of an epitaxially grown SiGe on Si solar cell by growing a higher Ge composition SiGe layer in the base. The purpose of growing a higher Ge composition SiGe layer in the base is to improve the light absorption. The first iteration of this structure was an Si0.18Ge0.82 solar cell fabricated with a 1 μm thick Si0.12Ge0.88 layer in the base. This solar cell had a lower efficiency compared with the reference solar cell without the Si0.12Ge0.88 layer. One of the main reasons for the lower efficiency is believed to be the high threading dislocation density (TDD) caused by the abrupt change of lattice constant between Si0.18Ge0.82 and Si0.12Ge0.88 in the base. In order to reduce the TDD, the second iteration of the structure was fabricated with a compositionally graded SiGe base. With the new structure, an SiGe on Si solar cell with an efficiency of 3.1%, when filtered by a GaAs0.79P0.21 top cell, was fabricated. The Ge composition in the base of this solar cell gradually increased from 82% to 85% and then decreased again to 82%. The developed SiGe solar cell with graded base provides more flexibility for a highly efficient GaAsP/SiGe dual junction solar cell grown on an Si substrate.

  20. In vitro and in vivo study of epigallocatechin-3-gallate-induced apoptosis in aerobic glycolytic hepatocellular carcinoma cells involving inhibition of phosphofructokinase activity

    PubMed Central

    Li, Sainan; Wu, Liwei; Feng, Jiao; Li, Jingjing; Liu, Tong; Zhang, Rong; Xu, Shizan; Cheng, Keran; Zhou, Yuqing; Zhou, Shunfeng; Kong, Rui; Chen, Kan; Wang, Fan; Xia, Yujing; Lu, Jie; Zhou, Yingqun; Dai, Weiqi; Guo, Chuanyong

    2016-01-01

    Glycolysis, as an altered cancer cell-intrinsic metabolism, is an essential hallmark of cancer. Phosphofructokinase (PFK) is a metabolic sensor in the glycolytic pathway, and restricting the substrate availability for this enzyme has been researched extensively as a target for chemotherapy. In the present study, we investigated that the effects of epigallocatechin-3-gallate (EGCG), an active component of green tea, on inhibiting cell growth and inducing apoptosis by promoting a metabolic shift away from glycolysis in aerobic glycolytic hepatocellular carcinoma (HCC) cells. EGCG modulated the oligomeric structure of PFK, potentially leading to metabolic stress associated apoptosis and suggesting that EGCG acts by directly suppressing PFK activity. A PFK activity inhibitor enhanced the effect, while the allosteric activator reversed EGCG-induced HCC cell death. PFK siRNA knockdown-induced apoptosis was not reversed by the activator. EGCG enhanced the effect of sorafenib on cell growth inhibition in both aerobic glycolytic HCC cells and in a xenograft mouse model. The present study suggests a potential role for EGCG as an adjuvant in cancer therapy, which merits further investigation at the clinical level. PMID:27349173

  1. Salicylic acid induces apoptosis in colon carcinoma cells grown in-vitro: Influence of oxygen and salicylic acid concentration

    SciTech Connect

    Zitta, Karina; Meybohm, Patrick; Bein, Berthold; Huang, Ying; Heinrich, Christin; Scholz, Jens; Steinfath, Markus; Albrecht, Martin

    2012-04-15

    In solid tumors the hypoxic environment can promote tumor progression and resistance to therapy. Recently, acetylsalicylic acid a major component of analgesic drugs and its metabolite salicylic acid (SA) have been shown to reduce the risk of colon cancer, but the mechanisms of action remain still unclear. Here we elucidate the effects of physiologically relevant concentrations of SA on colon carcinoma cells (CaCo-2) grown under normoxic and hypoxic conditions. Western blotting, caspase-3/7 apoptosis assays, MTS cell-proliferation assays, LDH cytotoxicity assays and hydrogen peroxide measurements were performed to investigate the effects of 1 and 10 {mu}M SA on CaCo-2 cells grown under normoxic conditions and cells exposed to hypoxia. Under normoxic conditions, SA did not influence cell proliferation or LDH release of CaCo-2 cells. However, caspase-3/7 activity was significantly increased. Under hypoxia, cell proliferation was reduced and LDH release and caspase-3/7 activities were increased. None of these parameters was altered by the addition of SA under hypoxic conditions. Hypoxia increased hydrogen peroxide concentrations 300-fold and SA significantly augmented the release of hydrogen peroxide under normoxic, but not under hypoxic conditions. Phosphorylation of the pro-survival kinases akt and erk1/2 was not changed by SA under hypoxic conditions, whereas under normoxia SA reduced phosphorylation of erk1/2 after 2 hours. We conclude that in colon carcinoma cells effects of SA on apoptosis and cellular signaling are dependent on the availability of oxygen. -- Highlights: Black-Right-Pointing-Pointer Effects of salicylic acid on colon carcinoma cells grown under normoxic and hypoxic conditions Black-Right-Pointing-Pointer Salicylic acid increases caspase-3/7 activity and hydrogen peroxide release under normoxia Black-Right-Pointing-Pointer Salicylic acid decreases pro-survival erk-1/2 phosphorylation under normoxia Black-Right-Pointing-Pointer Salicylic acid does

  2. Aerobic and anaerobic degradation of a range of alkyl sulfides by a denitrifying marine bacterium

    USGS Publications Warehouse

    Visscher, P.T.; Taylor, B.F.

    1993-01-01

    A pure culture of a bacterium was obtained from a marine microbial mat by using an anoxic medium containing dimethyl sulfide (DMS) and nitrate. The isolate grew aerobically or anaerobically as a denitrifier on alkyl sulfides, including DMS, dimethyl disulfide, diethyl sulfide (DES), ethyl methyl sulfide, dipropyl sulfide, dibutyl sulfide, and dibutyl disulfide. Cells grown on an alkyl sulfide or disulfide also oxidized the corresponding thiols, namely, methanethiol, ethanethiol, propanethiol, or butanethiol. Alkyl sulfides were metabolized by induced or derepressed cells with oxygen, nitrate, or nitrite as electron acceptor. Cells grown on DMS immediately metabolized DMS, but there was a lag before DES was consumed; with DES-grown cells, DES was immediately used but DMS was used only after a lag. Chloramphenicol prevented the eventual use of DES by DMS-grown cells and DMS use by DES-grown cells, respectively, indicating separate enzymes for the metabolism of methyl and ethyl groups. Growth was rapid on formate, acetate, propionate, and butyrate but slow on methanol. The organism also grew chemolithotrophically on thiosulfate with a decrease in pH; growth required carbonate in the medium. Growth on sulfide was also carbonate dependent but slow. The isolate was identified as a Thiobacillus sp. and designated strain ASN-1. It may have utility for removing alkyl sulfides, and also nitrate, nitrite, and sulfide, from wastewaters.

  3. Selectively-grown InGaP/GaAs on silicon heterostructures for application to photovoltaic photoelectrolysis cells

    NASA Astrophysics Data System (ADS)

    Mauk, Michael G.; Tata, Anthony N.; Feyock, Bryan W.

    2001-05-01

    Photovoltaic-photoelectrochemical (PV-PEC) cells based on InGaP/GaAs show excellent prospects for efficient production of hydrogen by electrolysis of water using solar energy. We describe a combined close-spaced vapor transport (CSVT)/liquid-phase epitaxy (LPE) process to produce arrays of selectively-grown mesas of InGaP/GaAs on silicon substrates. Unlike other semiconductor devices, the PV-PEC cell is well suited for such selectively-grown, discontinuous heteroepitaxial films. Thus, this device application affords exploiting the potential advantages of selective epitaxy, namely, the substantial reduction of stress and defects caused by thermal expansion and lattice mismatch between the silicon substrate and III-V epilayers.

  4. Teaching Aerobic Fitness Concepts.

    ERIC Educational Resources Information Center

    Sander, Allan N.; Ratliffe, Tom

    2002-01-01

    Discusses how to teach aerobic fitness concepts to elementary students. Some of the K-2 activities include location, size, and purpose of the heart and lungs; the exercise pulse; respiration rate; and activities to measure aerobic endurance. Some of the 3-6 activities include: definition of aerobic endurance; heart disease risk factors;…

  5. Accumulation of a novel glycolipid and a betaine lipid in cells of Rhodobacter sphaeroides grown under phosphate limitation.

    PubMed

    Benning, C; Huang, Z H; Gage, D A

    1995-02-20

    Cells of the photosynthetic bacterium Rhodobacter sphaeroides grown under phosphate-limiting conditions accumulated nonphosphorous glycolipids and lipids carrying head groups derived from amino acids. Concomitantly, the relative amount of phosphoglycerolipids decreased from 90 to 22 mol% of total polar lipids in the membranes. Two lipids, not detectable in cells grown under standard conditions, were synthesized during phosphate-limited growth. Fast atom bombardment mass spectroscopy, exact mass measurements, 1H NMR spectroscopy, sugar composition analysis, and methylation analysis of the predominant glycolipid led to the identification of the novel compound 1,2-di-O-acyl-3-O-[alpha-D-glucopyranosyl-(1-->4)-O-beta-D-galactopyr anosyl]glycerol. The second lipid was identified as the betaine lipid 1,2-di-O-acyl-[4'-(N,N,N-trimethyl)-homoserine]glycerol by cochromatography employing an authentic standard from Chlamydomonas reinhardtii, fast atom bombardment mass spectroscopy, exact mass measurements, and 1H NMR spectroscopy. Prior to this observation, the occurrence of this lipid was thought to be restricted to lower plants and algae. Apparently, these newly synthesized nonphosphorous lipids, in addition to the sulfo- and the ornithine lipid also found in R. sphaeroides grown under optimal conditions, take over the role of phosphoglycerolipids in phosphate-deprived cells.

  6. Metabolic reprogramming towards aerobic glycolysis correlates with greater proliferative ability and resistance to metabolic inhibition in CD8 versus CD4 T cells.

    PubMed

    Cao, Yilin; Rathmell, Jeffrey C; Macintyre, Andrew N

    2014-01-01

    T lymphocytes (T cells) undergo metabolic reprogramming after activation to provide energy and biosynthetic materials for growth, proliferation and differentiation. Distinct T cell subsets, however, adopt metabolic programs specific to support their needs. As CD4 T cells coordinate adaptive immune responses while CD8 T cells become cytotoxic effectors, we compared activation-induced proliferation and metabolic reprogramming of these subsets. Resting CD4 and CD8 T cells were metabolically similar and used a predominantly oxidative metabolism. Following activation CD8 T cells proliferated more rapidly. Stimulation led both CD4 and CD8 T cells to sharply increase glucose metabolism and adopt aerobic glycolysis as a primary metabolic program. Activated CD4 T cells, however, remained more oxidative and had greater maximal respiratory capacity than activated CD8 T cells. CD4 T cells were also associated with greater levels of ROS and increased mitochondrial content, irrespective of the activation context. CD8 cells were better able, however, to oxidize glutamine as an alternative fuel source. The more glycolytic metabolism of activated CD8 T cells correlated with increased capacity for growth and proliferation, along with reduced sensitivity of cell growth to metabolic inhibition. These specific metabolic programs may promote greater growth and proliferation of CD8 T cells and enhance survival in diverse nutrient conditions.

  7. Effects of U0126 and MK2206 on cell growth and re-growth of endometriotic stromal cells grown on substrates of varying stiffness

    PubMed Central

    Matsuzaki, Sachiko; Pouly, Jean-Luc; Canis, Michel

    2017-01-01

    Endometriosis is a common gynecological disorder responsible for infertility and pelvic pain. A complete cure for patients with endometriosis awaits new targets and strategies. Here we show that U0126 (a MEK inhibitor) and MK2206 (an AKT inhibitor) synergistically inhibit cell growth of deep endometriotic stromal cells (DES) grown on polyacrylamide gel substrates (PGS) of varying stiffness (2 or 30 kilopascal [kPa]) or plastic in vitro. No significant differences in cell proliferation were observed among DES, endometrial stromal cells of patients with endometriosis (EES) from the proliferative phase (P), EES-S (secretory phase) and EES-M (menstrual phase) compared to cells grown on a substrate of the same stiffness at both higher (U0126 [30 μM] and MK2206 [9 μM]) and lower (U0126 [15 μM] and MK2206 [4.5 μM]) combined doses. However, cell re-growth of DES after drug discontinuation was higher than that of EES-P and EES-S when cells were grown on rigid substrates at both combined doses. Combination U0126 and MK2206 treatment is more effective than each drug alone in cell growth inhibition of DES. However, further studies are required to investigate the mechanisms underlying high cell survival and proliferation after drug discontinuation for developing target therapies that prevent recurrence. PMID:28218307

  8. Alteration of photochemistry and protein degradation of photosystem II from Chlamydomonas reinhardtii under high salt grown cells.

    PubMed

    Neelam, Satyabala; Subramanyam, Rajagopal

    2013-07-05

    In this study, we evaluated the inhibitory effect of NaCl on cell growth, photochemistry and protein profile of photosystem (PS) II in Chlamydomonas reinhardtii. To study the effect of NaCl on the photosynthetic apparatus, the C. reinhardtii cells were grown at different concentrations (0, 50, 100 and 150 mM). NaCl induced flagellar resorption due to which the cells lost their motility, formation of palmelloids, reduced cell size and slower cell division. Chlorophyll fluorescence transients at different NaCl concentrations had decreased intensities of all peaks (OJIP) indicating the apparent inactivation energies of both donor and acceptor side of PSII. Consequently, inhibition of electron transport occurred particularly at PSII. Further, low temperature emission spectra showed that the rate of damage to the PSII was more when compared to PSI. Also, we have carried out the visible circular dichroism spectra from thylakoids where the major peaks contributed to chlorophyll a and b are equally reduced in different salt grown cells, which may explain the changes at the level of inter pigment-pigment interactions. Furthermore protein profile analysis of PSII revealed that the major subunit of light harvesting complex (LHC)II is more prone to salt stress than core proteins of PSII indicating the light harvesting funnel from LHCII to PSII core is impaired.

  9. Evaluation of normal and metastatic mammary cells grown in different biomaterial matrices: establishing potential tissue test systems.

    PubMed

    Booth, Brian W; Park, Jang Pyo; Burg, Karen J L

    2013-01-01

    The in vitro growth and differentiation of normal mammalian cells is quite different than the growth of cells derived from tumors. Additionally, cells of the same origin (tissue) behave differently depending on the biomaterial matrix in or on which they are grown in vitro. We examined both Matrigel(TM) and a collagen/agarose blend and demonstrated that two murine mammary derived cells lines, 4T1 and NMuMG, derived from a metastatic mammary tumor or a normal mammary gland, respectively, exhibit different growth and differentiation patterns depending on the three-dimensional matrix in which they are grown. The shape and size of the colonies that formed were matrix dependent. The two cell lines produced different levels of growth factors and metalloproteinases, and expressed differentiation markers specific to a matrix. Through the classification of different cell behaviors in different growth matrices, we will be able to intelligently design and tune tissue test systems to ask and answer specific challenging scientific questions.

  10. Growth and characterization of Czochralski-grown n and p-type GaAs for space solar cell substrates

    NASA Technical Reports Server (NTRS)

    Chen, R. T.

    1983-01-01

    Progress in LEC (liquid encapsulated Czochralski) crystal growth techniques for producing high-quality, 3-inch-diameter, n- and p-type GaAs crystals suitable for solar cell applications is described. The LEC crystals with low dislocation densities and background impurities, high electrical mobilities, good dopant uniformity, and long diffusion lengths were reproducibly grown through control of the material synthesis, growth and doping conditions. The capability for producing these large-area, high-quality substrates should positively impact the manufacturability of highly efficiency, low cost, radiation-hard GaAs solar cells.

  11. Epitaxial Crystal Silicon Absorber Layers and Solar Cells Grown at 1.8 Microns per Minute: Preprint

    SciTech Connect

    Bobela, D. C.; Teplin, C. W.; Young, D. L.; Branz, H. M.; Stradins, P.

    2011-07-01

    We have grown device-quality epitaxial silicon thin films at growth rates up to 1.8 μm/min, using hot-wire chemical vapor deposition from silane at substrate temperatures below 750 degrees C. At these rates, which are more than 30 times faster than those used by the amorphous and nanocrystalline Si industry, capital costs for large-scale solar cell production would be dramatically reduced, even for cell absorber layers up to 10 ?m thick. We achieved high growth rates by optimizing the three key parameters: silane flow, depletion, and filament geometry, based on our model developed earlier. Hydrogen coverage of the filament surface likely limits silane decomposition and growth rate at high system pressures. No considerable deterioration in PV device performance is observed when grown at high rate, provided that the epitaxial growth is initiated at low rate. A simple mesa device structure (wafer/epi Si/a-Si(i)/a-Si:H(p)/ITO) with a 2.3 um epitaxial silicon absorber layer was grown at 700 nm/min. The finished device had an open-circuit voltage of 0.424 V without hydrogenation treatment.

  12. Aerobically respiring prokaryotic strains exhibit a broader temperature–pH–salinity space for cell division than anaerobically respiring and fermentative strains

    PubMed Central

    Harrison, Jesse P.; Dobinson, Luke; Freeman, Kenneth; McKenzie, Ross; Wyllie, Dale; Nixon, Sophie L.; Cockell, Charles S.

    2015-01-01

    Biological processes on the Earth operate within a parameter space that is constrained by physical and chemical extremes. Aerobic respiration can result in adenosine triphosphate yields up to over an order of magnitude higher than those attained anaerobically and, under certain conditions, may enable microbial multiplication over a broader range of extremes than other modes of catabolism. We employed growth data published for 241 prokaryotic strains to compare temperature, pH and salinity values for cell division between aerobically and anaerobically metabolizing taxa. Isolates employing oxygen as the terminal electron acceptor exhibited a considerably more extensive three-dimensional phase space for cell division (90% of the total volume) than taxa using other inorganic substrates or organic compounds as the electron acceptor (15% and 28% of the total volume, respectively), with all groups differing in their growth characteristics. Understanding the mechanistic basis of these differences will require integration of research into microbial ecology, physiology and energetics, with a focus on global-scale processes. Critical knowledge gaps include the combined impacts of diverse stress parameters on Gibbs energy yields and rates of microbial activity, interactions between cellular energetics and adaptations to extremes, and relating laboratory-based data to in situ limits for cell division. PMID:26354829

  13. Comparison of aerobic and photosynthetic Rhodobacter sphaeroides 2.4.1 proteomes

    SciTech Connect

    Callister, Stephen J.; Nicora, Carrie D.; Zeng, Xiaohua; Roh, Jung Hyeob; Dominguez, Migual; Tavano, Christine; Monroe, Matthew E.; Kaplan, Samuel; Donohue, Timothy; Smith, Richard D.; Lipton, Mary S.

    2006-07-05

    Proteomes from aerobic and photosynthetic grown Rhodobacter sphaeroides 2.4.1 cell cultures were characterized using liquid chromatography-mass spectrometry in conjunction with an accurate mass and elution time (AMT) tag approach. Roughly 8000 high quality peptides were detected that represented 1,445 gene products and 34% of the predicted proteins. The identified proteins corresponded primarily to open reading frames (ORFs) contained within the two chromosomal elements of this bacterium, but a significant number were also observed from ORFs associated with 5 naturally occurring plasmids. Data mining of peptides revealed a number of proteins uniquely detected within the photosynthetic cell culture. Proteins observed in both aerobic respiratory and photosynthetic grown cultures were analyzed semi-quantitatively by comparing their estimated abundances to provide insights into bioenergetic models for aerobic respiration and photosynthesis. Additional emphasis was placed on gene products annotated as hypothetical to gain information as to their potential roles within these two growth conditions. Where possible, transcriptome data for R. sphaeroides obtained under the same culture conditions were compared with these results. This comparative study demonstrated the applicability of the AMT tag approach for high-throughput proteomic analyses of pathways associated with the photosynthetic lifestyle.

  14. Inactivation of Mg chelatase during transition from anaerobic to aerobic growth in Rhodobacter capsulatus.

    PubMed

    Willows, Robert D; Lake, Vanessa; Roberts, Thomas Hugh; Beale, Samuel I

    2003-06-01

    The facultative photosynthetic bacterium Rhodobacter capsulatus can adapt from an anaerobic photosynthetic mode of growth to aerobic heterotrophic metabolism. As this adaptation occurs, the cells must rapidly halt bacteriochlorophyll synthesis to prevent phototoxic tetrapyrroles from accumulating, while still allowing heme synthesis to continue. A likely control point is Mg chelatase, the enzyme that diverts protoporphyrin IX from heme biosynthesis toward the bacteriochlorophyll biosynthetic pathway by inserting Mg(2+) to form Mg-protoporphyrin IX. Mg chelatase is composed of three subunits that are encoded by the bchI, bchD, and bchH genes in R. capsulatus. We report that BchH is the rate-limiting component of Mg chelatase activity in cell extracts. BchH binds protoporphyrin IX, and BchH that has been expressed and purified from Escherichia coli is red in color due to the bound protoporphyrin IX. Recombinant BchH is rapidly inactivated by light in the presence of O(2), and the inactivation results in the formation of a covalent adduct between the protein and the bound protoporphyrin IX. When photosynthetically growing R. capsulatus cells are transferred to aerobic conditions, Mg chelatase is rapidly inactivated, and BchH is the component that is most rapidly inactivated in vivo when cells are exposed to aerobic conditions. The light- and O(2)-stimulated inactivation of BchH could account for the rapid inactivation of Mg chelatase in vivo and provide a mechanism for inhibiting the synthesis of bacteriochlorophyll during adaptation of photosynthetically grown cells to aerobic conditions while still allowing heme synthesis to occur for aerobic respiration.

  15. Single Junction InGaP/GaAs Solar Cells Grown on Si Substrates using SiGe Buffer Layers

    NASA Technical Reports Server (NTRS)

    Ringel, S. A.; Carlin, J. A.; Andre, C. L.; Hudait, M. K.; Gonzalez, M.; Wilt, D. M.; Clark, E. B.; Jenkins, P.; Scheiman, D.; Allerman, A.

    2002-01-01

    Single junction InGaP/GaAs solar cells displaying high efficiency and record high open circuit voltage values have been grown by metalorganic chemical vapor deposition on Ge/graded SiGe/Si substrates. Open circuit voltages as high as 980 mV under AM0 conditions have been verified to result from a single GaAs junction, with no evidence of Ge-related sub-cell photoresponse. Current AM0 efficiencies of close to 16% have been measured for a large number of small area cells, whose performance is limited by non-fundamental current losses due to significant surface reflection resulting from greater than 10% front surface metal coverage and wafer handling during the growth sequence for these prototype cells. It is shown that at the material quality currently achieved for GaAs grown on Ge/SiGe/Si substrates, namely a 10 nanosecond minority carrier lifetime that results from complete elimination of anti-phase domains and maintaining a threading dislocation density of approximately 8 x 10(exp 5) per square centimeter, 19-20% AM0 single junction GaAs cells are imminent. Experiments show that the high performance is not degraded for larger area cells, with identical open circuit voltages and higher short circuit current (due to reduced front metal coverage) values being demonstrated, indicating that large area scaling is possible in the near term. Comparison to a simple model indicates that the voltage output of these GaAs on Si cells follows ideal behavior expected for lattice mismatched devices, demonstrating that unaccounted for defects and issues that have plagued other methods to epitaxially integrate III-V cells with Si are resolved using SiGe buffers and proper GaAs nucleation methods. These early results already show the enormous and realistic potential of the virtual SiGe substrate approach for generating high efficiency, lightweight and strong III-V solar cells.

  16. Effects of growth temperature and device structure on GaP solar cells grown by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Vaisman, M.; Tomasulo, S.; Masuda, T.; Lang, J. R.; Faucher, J.; Lee, M. L.

    2015-02-01

    Gallium phosphide (GaP) is an attractive candidate for wide-bandgap solar cell applications, possessing the largest bandgap of the III-arsenide/phosphides without aluminum. However, GaP cells to date have exhibited poor internal quantum efficiency (IQE), even for photons absorbed by direct transitions, motivating improvements in material quality and device structure. In this work, we investigated GaP solar cells grown by molecular beam epitaxy over a range of substrate temperatures, employing a much thinner emitter than in prior work. Higher growth temperatures yielded the best solar cell characteristics, indicative of increased diffusion lengths. Furthermore, the inclusion of an AlGaP window layer improved both open-circuit voltage and short wavelength IQE.

  17. Effects of growth temperature and device structure on GaP solar cells grown by molecular beam epitaxy

    SciTech Connect

    Vaisman, M.; Tomasulo, S.; Masuda, T.; Lang, J. R.; Faucher, J.; Lee, M. L.

    2015-02-09

    Gallium phosphide (GaP) is an attractive candidate for wide-bandgap solar cell applications, possessing the largest bandgap of the III-arsenide/phosphides without aluminum. However, GaP cells to date have exhibited poor internal quantum efficiency (IQE), even for photons absorbed by direct transitions, motivating improvements in material quality and device structure. In this work, we investigated GaP solar cells grown by molecular beam epitaxy over a range of substrate temperatures, employing a much thinner emitter than in prior work. Higher growth temperatures yielded the best solar cell characteristics, indicative of increased diffusion lengths. Furthermore, the inclusion of an AlGaP window layer improved both open-circuit voltage and short wavelength IQE.

  18. Production of Newcastle Disease Virus by Vero Cells Grown on Cytodex 1 Microcarriers in a 2-Litre Stirred Tank Bioreactor

    PubMed Central

    Arifin, Mohd Azmir; Mel, Maizirwan; Abdul Karim, Mohamed Ismail; Ideris, Aini

    2010-01-01

    The aim of this study is to prepare a model for the production of Newcastle disease virus (NDV) lentogenic F strain using cell culture in bioreactor for live attenuated vaccine preparation. In this study, firstly we investigated the growth of Vero cells in several culture media. The maximum cell number was yielded by culture of Vero cells in Dulbecco's Modified Eagle Medium (DMEM) which was 1.93 × 106 cells/ml. Secondly Vero cells were grown in two-litre stirred tank bioreactor by using several commercial microcarriers. We achieved the maximum cell concentration about 7.95 × 105 cells/ml when using Cytodex 1. Later we produced Newcastle Disease virus in stirred tank bioreactor based on the design developed using Taguchi L4 method. Results reveal that higher multiplicity of infection (MOI) and size of cell inoculums can yield higher virus titer. Finally, virus samples were purified using high-speed centrifugation based on 3∗∗(3-1) Fractional Factorial Design. Statistical analysis showed that the maximum virus titer can be achieved at virus sample concentration of 58.45% (v/v), centrifugation speed of 13729 rpm, and centrifugation time of 4 hours. As a conclusion, high yield of virus titer could be achieved through optimization of cell culture in bioreactor and separation by high-speed centrifugation. PMID:20625497

  19. Evaluation of multiwalled carbon nanotube cytotoxicity in cultures of human brain microvascular endothelial cells grown on plastic or basement membrane.

    PubMed

    Eldridge, Brittany N; Xing, Fei; Fahrenholtz, Cale D; Singh, Ravi N

    2017-03-09

    There is a growing interest in the use of multiwalled carbon nanotubes (MWCNTs) to treat diseases of the brain. Little is known about the effects of MWCNTs on human brain microvascular endothelial cells (HBMECs), which make up the blood vessels in the brain. In our studies, we evaluate the cytotoxicity of MWCNTs and acid oxidized MWNCTs, with or without a phospholipid-polyethylene glycol coating. We determined the cytotoxic effects of MWCNTs on both tissue-mimicking cultures of HBMECs grown on basement membrane and on monolayer cultures of HBMECs grown on plastic. We also evaluated the effects of MWCNT exposure on the capacity of HBMECs to form rings after plating on basement membrane, a commonly used assay to evaluate angiogenesis. We show that tissue-mimicking cultures of HBMECs are less sensitive to all types of MWCNTs than monolayer cultures of HBMECs. Furthermore, we found that MWCNTs have little impact on the capacity of HBMECs to form rings. Our results indicate that relative cytotoxicity of MWCNTs is significantly affected by the type of cell culture model used for testing, and supports further research into the use of tissue-mimicking endothelial cell culture models to help bridge the gap between in vitro and in vivo toxicology.

  20. Effects of Female Sex Hormones on Susceptibility to HSV-2 in Vaginal Cells Grown in Air-Liquid Interface

    PubMed Central

    Lee, Yung; Dizzell, Sara E.; Leung, Vivian; Nazli, Aisha; Zahoor, Muhammad A.; Fichorova, Raina N.; Kaushic, Charu

    2016-01-01

    The lower female reproductive tract (FRT) is comprised of the cervix and vagina, surfaces that are continuously exposed to a variety of commensal and pathogenic organisms. Sexually transmitted viruses, such as herpes simplex virus type 2 (HSV-2), have to traverse the mucosal epithelial lining of the FRT to establish infection. The majority of current culture systems that model the host-pathogen interactions in the mucosal epithelium have limitations in simulating physiological conditions as they employ a liquid-liquid interface (LLI), in which both apical and basolateral surfaces are submerged in growth medium. We designed the current study to simulate in vivo conditions by growing an immortalized vaginal epithelial cell line (Vk2/E6E7) in culture with an air-liquid interface (ALI) and examined the effects of female sex hormones on their growth, differentiation, and susceptibility to HSV-2 under these conditions, in comparison to LLI cultures. ALI conditions induced Vk2/E6E7 cells to grow into multi-layered cultures compared to the monolayers present in LLI conditions. Vk2 cells in ALI showed higher production of cytokeratin in the presence of estradiol (E2), compared to cells grown in progesterone (P4). Cells grown under ALI conditions were exposed to HSV-2-green fluorescent protein (GFP) and the highest infection and replication was observed in the presence of P4. Altogether, this study suggests that ALI cultures more closely simulate the in vivo conditions of the FRT compared to the conventional LLI cultures. Furthermore, under these conditions P4 was found to confer higher susceptibility to HSV-2 infection in vaginal cells. The vaginal ALI culture system offers a better alternative to study host-pathogen interactions. PMID:27589787

  1. Effects of Female Sex Hormones on Susceptibility to HSV-2 in Vaginal Cells Grown in Air-Liquid Interface.

    PubMed

    Lee, Yung; Dizzell, Sara E; Leung, Vivian; Nazli, Aisha; Zahoor, Muhammad A; Fichorova, Raina N; Kaushic, Charu

    2016-08-30

    The lower female reproductive tract (FRT) is comprised of the cervix and vagina, surfaces that are continuously exposed to a variety of commensal and pathogenic organisms. Sexually transmitted viruses, such as herpes simplex virus type 2 (HSV-2), have to traverse the mucosal epithelial lining of the FRT to establish infection. The majority of current culture systems that model the host-pathogen interactions in the mucosal epithelium have limitations in simulating physiological conditions as they employ a liquid-liquid interface (LLI), in which both apical and basolateral surfaces are submerged in growth medium. We designed the current study to simulate in vivo conditions by growing an immortalized vaginal epithelial cell line (Vk2/E6E7) in culture with an air-liquid interface (ALI) and examined the effects of female sex hormones on their growth, differentiation, and susceptibility to HSV-2 under these conditions, in comparison to LLI cultures. ALI conditions induced Vk2/E6E7 cells to grow into multi-layered cultures compared to the monolayers present in LLI conditions. Vk2 cells in ALI showed higher production of cytokeratin in the presence of estradiol (E2), compared to cells grown in progesterone (P4). Cells grown under ALI conditions were exposed to HSV-2-green fluorescent protein (GFP) and the highest infection and replication was observed in the presence of P4. Altogether, this study suggests that ALI cultures more closely simulate the in vivo conditions of the FRT compared to the conventional LLI cultures. Furthermore, under these conditions P4 was found to confer higher susceptibility to HSV-2 infection in vaginal cells. The vaginal ALI culture system offers a better alternative to study host-pathogen interactions.

  2. High-Potential Electrocatalytic O2 Reduction with Nitroxyl / NOx Mediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

    SciTech Connect

    Gerken, James B.; Stahl, Shannon S.

    2015-07-15

    Efficient reduction of O2 to water is a central challenge in energy conversion and aerobic oxidation catalysis. In the present study, we investigate the electrochemical reduction of O2 with soluble organic nitroxyl and nitrogen oxide (NOx) mediators. When used alone, neither organic nitroxyls, such as TEMPO (2,2,6,6-tetramethyl-1-piperidinyl-N-oxyl), nor NOx species, such as sodium nitrite, are effective mediators of electrochemical O2 reduction. The combination of nitroxyl/NOx species, however, mediates sustained O2 reduction at electrochemical potentials of 0.19–0.33 V (vs. Fc/Fc+) in acetonitrile containing trifluoroacetic acid. Mechanistic analysis of the coupled redox reactions supports a process in which the nitrogen oxide catalyst drives aerobic oxidation of a nitroxyl mediator to an oxoammonium species, which then is reduced back to the nitroxyl at the cathode. The electrolysis potential is dictated by the oxoammonium/nitroxyl reduction potential. The high potentials observed with this ORR system benefit from the mechanism-based specificity for four-electron reduction of oxygen to water mediated by NOx species, together with kinetically efficient reduction of oxidized NOx species by TEMPO and other organic nitroxyls. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center, funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  3. Radioassay for Hydrogenase Activity in Viable Cells and Documentation of Aerobic Hydrogen-Consuming Bacteria Living in Extreme Environments

    PubMed Central

    Schink, Bernhard; Lupton, F. S.; Zeikus, J. G.

    1983-01-01

    An isotopic tracer assay based on the hydrogenase-dependent formation of tritiated water from tritium gas was developed for in life analysis of microbial hydrogen transformation. This method allowed detection of bacterial hydrogen metabolism in pure cultures or in natural samples obtained from aquatic ecosystems. A differentiation between chemical-biological and aerobic-anaerobic hydrogen metabolism was established by variation of the experimental incubation temperature or by addition of selective inhibitors. Hydrogenase activity was shown to be proportional to the consumption or production of hydrogen by cultures of Desulfovibrio vulgaris, Clostridium pasteurianum, and Methanosarcina barkeri. This method was applied, in connection with measurements of free hydrogen and most-probable-number enumerations, in aerobic natural source waters to establish the activity and document the ecology of hydrogen-consuming bacteria in extreme acid, thermal, or saline environments. The utility of the assay is based in part on the ability to quantify bacterial hydrogen transformation at natural hydrogen partial pressures, without the use of artificial electron acceptors. PMID:16346288

  4. High-Potential Electrocatalytic O2 Reduction with Nitroxyl/NOx Mediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

    PubMed Central

    2015-01-01

    Efficient reduction of O2 to water is a central challenge in energy conversion and many aerobic oxidation reactions. Here, we show that the electrochemical oxygen reduction reaction (ORR) can be achieved at high potentials by using soluble organic nitroxyl and nitrogen oxide (NOx) mediators. When used alone, neither organic nitroxyls, such as 2,2,6,6-tetramethyl-1-piperidinyl-N-oxyl (TEMPO), nor NOx species, such as sodium nitrite, are effective ORR mediators. The combination of nitroxyl/NOx species, however, mediates sustained O2 reduction with overpotentials as low as 300 mV in acetonitrile containing trifluoroacetic acid. Mechanistic analysis of the coupled redox reactions supports a process in which the nitrogen oxide catalyst drives aerobic oxidation of a nitroxyl mediator to an oxoammonium species, which then is reduced back to the nitroxyl at the cathode. The electrolysis potential is dictated by the oxoammonium/nitroxyl reduction potential. The overpotentials accessible with this ORR system are significantly lower than widely studied molecular metal-macrocycle ORR catalysts and benefit from the mechanism-based specificity for four-electron reduction of oxygen to water mediated by NOx species, together with kinetically efficient reduction of oxidized NOx species by TEMPO and other organic nitroxyls. PMID:27162977

  5. Aerobic carboxydotrophy under extremely haloalkaline conditions in Alkalispirillum/Alkalilimnicola strains isolated from soda lakes.

    PubMed

    Sorokin, Dimitry Yu; Tourova, Tatjana P; Kovaleva, Olga L; Kuenen, J Gijs; Muyzer, Gerard

    2010-03-01

    Aerobic enrichments from soda lake sediments with CO as the only substrate resulted in the isolation of five bacterial strains capable of autotrophic growth with CO at extremely high pH and salinity. The strains belonged to the Alkalispirillum/Alkalilimnicola cluster in the Gammaproteobacteria, where the ability to oxidize CO, but not growth with CO, has been demonstrated previously. The growth with CO was possible only at an oxygen concentration below 5 % and CO concentration below 20 % in the gas phase. The isolates were also capable of growth with formate but not with H(2). The carboxydotrophic growth occurred within a narrow pH range from 8 to 10.5 (optimum at 9.5) and a broad salt concentration from 0.3 to 3.5 M total Na(+) (optimum at 1.0 M). Cells grown on CO had high respiration activity with CO and formate, while the cells grown on formate actively oxidized formate alone. In CO-grown cells, CO-dehydrogenase (CODH) activity was detectable both in soluble and membrane fractions, while the NAD-independent formate dehydrogenase (FDH) resided solely in membranes. The results of total protein profiling and the failure to detect CODH with conventional primers for the coxL gene indicated that the CO-oxidizing enzyme in haloalkaliphilic isolates might differ from the classical aerobic CODH complex. A single cbbL gene encoding the RuBisCO large subunit was detected in all strains, suggesting the presence of the Calvin cycle of inorganic carbon fixation. Overall, these results demonstrated the possibility of aerobic carboxydotrophy under extremely haloalkaline conditions.

  6. Aerobic condition increases carotenoid production associated with oxidative stress tolerance in Enterococcus gilvus.

    PubMed

    Hagi, Tatsuro; Kobayashi, Miho; Nomura, Masaru

    2014-01-01

    Although it is known that a part of lactic acid bacteria can produce carotenoid, little is known about the regulation of carotenoid production. The objective of this study was to determine whether aerobic growth condition influences carotenoid production in carotenoid-producing Enterococcus gilvus. Enterococcus gilvus was grown under aerobic and anaerobic conditions. Its growth was slower under aerobic than under anaerobic conditions. The decrease in pH levels and production of lactic acid were also lower under aerobic than under anaerobic conditions. In contrast, the amount of carotenoid pigments produced by E. gilvus was significantly higher under aerobic than under anaerobic conditions. Further, real-time quantitative reverse transcription PCR revealed that the expression level of carotenoid biosynthesis genes crtN and crtM when E. gilvus was grown under aerobic conditions was 2.55-5.86-fold higher than when it was grown under anaerobic conditions. Moreover, after exposure to 16- and 32-mM H2O2, the survival rate of E. gilvus grown under aerobic conditions was 61.5- and 72.5-fold higher, respectively, than when it was grown under anaerobic conditions. Aerobic growth conditions significantly induced carotenoid production and the expression of carotenoid biosynthesis genes in E. gilvus, resulting in increased oxidative stress tolerance.

  7. "allometry" Deterministic Approaches in Cell Size, Cell Number and Crude Fiber Content Related to the Physical Quality of Kangkong (Ipomoea reptans) Grown Under Different Plant Density Pressures

    NASA Astrophysics Data System (ADS)

    Selamat, A.; Atiman, S. A.; Puteh, A.; Abdullah, N. A. P.; Mohamed, M. T. M.; Zulkeefli, A. A.; Othman, S.

    Kangkong, especially the upland type (Ipomoea reptans) is popularly consumed as a vegetable dish in the South East Asian countries for its quality related to Vitamins (A and C) and crude fiber contents. Higher fiber contents would prevent from the occurrence of colon cancer and diverticular disease. With young stem edible portion, its cell number and size contribute to the stem crude fiber content. The mathematical approach of allometry of cell size, number, and fiber content of stem could be used in determining the 'best' plant density pressure in producing the quality young stem to be consumed. Basically, allometry is the ratio of relative increment (growth or change) rates of two parameters, or the change rate associated to the log of measured variables relationship. Kangkog grown equal or lower than 55 plants m-2 produced bigger individual plant and good quality (physical) kangkong leafy vegetable, but with lower total yield per unit area as compared to those grown at higher densities.

  8. WWOX loss activates aerobic glycolysis.

    PubMed

    Abu-Remaileh, Muhannad; Seewaldt, Victoria L; Aqeilan, Rami I

    2015-01-01

    Cancer cells undergo reprogramming of glucose metabolism to limit energy production to glycolysis-a state known as "aerobic glycolysis." Hypoxia-inducible factor 1 (HIF1α) is a transcription factor that regulates many genes responsible for this switch. As discussed here, new data suggest that the tumor suppressor WW domain-containing oxidoreductase (WWOX) modulates HIF1α, thereby regulating this metabolic state.

  9. WWOX loss activates aerobic glycolysis

    PubMed Central

    Abu-Remaileh, Muhannad; Seewaldt, Victoria L; Aqeilan, Rami I

    2015-01-01

    Cancer cells undergo reprogramming of glucose metabolism to limit energy production to glycolysis—a state known as “aerobic glycolysis.” Hypoxia-inducible factor 1 (HIF1α) is a transcription factor that regulates many genes responsible for this switch. As discussed here, new data suggest that the tumor suppressor WW domain-containing oxidoreductase (WWOX) modulates HIF1α, thereby regulating this metabolic state. PMID:27308416

  10. High-efficiency GaAs and GaInP solar cells grown by all solid-state molecular-beam-epitaxy.

    PubMed

    Lu, Shulong; Ji, Lian; He, Wei; Dai, Pan; Yang, Hui; Arimochi, Masayuki; Yoshida, Hiroshi; Uchida, Shiro; Ikeda, Masao

    2011-10-31

    We report the initial results of GaAs and GaInP solar cells grown by all solid-state molecular-beam-epitaxy (MBE) technique. For GaAs single-junction solar cell, with the application of AlInP as the window layer and GaInP as the back surface field layer, the photovoltaic conversion efficiency of 26% at one sun concentration and air mass 1.5 global (AM1.5G) is realized. The efficiency of 16.4% is also reached for GaInP solar cell. Our results demonstrate that the MBE-grown phosphide-contained III-V compound semiconductor solar cell can be quite comparable to the metal-organic-chemical-vapor-deposition-grown high-efficiency solar cell.

  11. Role of P13 Kinase Signaling Pathways in Polarity Determination of Human Mammary Epithelial Cells Grown in Three-Dimensional Extracellular Matrix

    DTIC Science & Technology

    2005-09-01

    morphogenesis, wound healing , and immune- cell trafficking (Friedl and Brocker 2000; Friedl and Wolf 2003). Unlike physiological processes of cell...Boyden chambers (Figure 1D, n=8). Since altered cell motility is the driving force of invasiveness, wound - healing and cell migration assays c were...AD Award Number: DAMD17-03-1-0099 TITLE: Role of P13 Kinase Signaling Pathways in Polarity Determination of Human Mammary Epithelial Cells Grown in

  12. A microcarrier cell culture process for propagating rabies virus in Vero cells grown in a stirred bioreactor under fully animal component free conditions.

    PubMed

    Rourou, Samia; van der Ark, Arno; van der Velden, Tiny; Kallel, Héla

    2007-05-10

    Rabies virus strain production in Vero cells grown on Cytodex 1 in a 2 L stirred tank bioreactor and in a medium free of components of human or animal origin (VP-SFM) is described. Cell banking procedure in VP-SFM supplemented with an animal components free mixture (10%DMSO+0.1%methylcellulose) was reported and cell growth after revitalization was assessed. Vero cells exhibited growth performances (specific growth rate and cell division number) similar to that obtained in serum containing medium. To design a scalable process that is totally free of animal-derived substances, two proteases: TrypLE Select and Accutase, were assessed as an alternative to trypsin which is routinely used for cell passage. Growth performance of Vero cells grown in VP-SFM and MEM+10% fetal calf serum (FCS) over four passages and subcultivated with either TrypLE Select or Accutase was evaluated. TrypLE Select showed the best performance in terms of specific growth rate and cell division number. Kinetics of cell growth and rabies virus production (LP2061/Vero strain) were investigated in spinner flask and in a 2 L bioreactor. In spinner flask, a maximal cell density level of 1.85x10(6) cells/mL was achieved when the cells were grown in VP-SFM on 2 g/L Cytodex 1. Cell infection experiments conducted at an MOI of 0.3 and without the medium exchange step, typically needed for serum containing rabies virus production, resulted in a maximal virus titer equal to 2x10(7) (Fluorescent Focus Unit) FFU/mL. In stirred tank bioreactor, Vero cell growth in VP-SFM on 3 g/L Cytodex 1 was shown to be sensitive to the aeration mode. Sparging the culture was detrimental for cell growth, whereas cell density level was greatly enhanced when only headspace aeration was used. A cell density level of 2.6x10(6) cells/mL was obtained when the cells were grown on 3g/L Cytodex 1 and in batch culture mode. Cell infection at an MOI of 0.1 without any medium exchange, yielded a maximal rabies virus titer of 2.4x10

  13. Temperature coefficients and radiation induced DLTS spectra of MOCVD grown n(+)p InP solar cells

    NASA Technical Reports Server (NTRS)

    Walters, Robert J.; Statler, Richard L.; Summers, Geoffrey P.

    1991-01-01

    The effects of temperature and radiation on n(+)p InP solar cells and mesa diodes grown by metallorganic chemical vapor deposition (MOCVD) were studied. It was shown that MOCVD is capable of consistently producing good quality InP solar cells with Eff greater than 19 percent which display excellent radiation resistance due to minority carrier injection and thermal annealing. It was also shown that universal predictions of InP device performance based on measurements of a small group of test samples can be expected to be quite accurate, and that the degradation of an InP device due to any incident particle spectrum should be predictable from a measurement following a single low energy proton irradiation.

  14. The effect of adriamycin and 4'-deoxydoxorubicin on cell survival of human lung tumour cells grown in monolayer and as spheroids.

    PubMed

    Kerr, D J; Wheldon, T E; Kerr, A M; Freshney, R I; Kaye, S B

    1986-09-01

    Using growth delay and clonogenic cell survival as end points, we have shown that the 3-dimensional structure of human lung tumour spheroids confers a degree of resistance to the anthracyclines adriamycin and 4'-deoxydoxorubicin, relative to cells grown as monolayer. 4'-deoxydoxorubicin induces a longer growth delay and greater clonogenic cell kill than adriamycin in spheroids, although it is no more cytotoxic in monolayer (exponential and plateau phase). There is a log linear relationship between clonogenic cell survival and duration of adriamycin exposure in monolayers, and biphasic curve with a lesser degree of cell kill for disaggregated spheroid cells. Using fluorescent microscopy we have demonstrated, qualitatively, that the more lipophilic analogue partitions into the spheroid more rapidly and to a greater degree than adriamycin. It is possible that adriamycin penetration is a relatively important aspect of spheroid drug resistance, which may be related to intraspheroidal pH gradients, and that we have partially overcome this by using a lipophilic analogue.

  15. Development of a 2.0 eV AlGaInP Solar Cell Grown by OMVPE

    SciTech Connect

    Perl, Emmett E.; Simon, John; Geisz, John F.; Olavarria, Waldo; Young, Michelle; Duda, Anna; Dippo, Pat; Friedman, Daniel J.; Steiner, Myles A.

    2015-06-14

    AlGaInP solar cells with a bandgap (Eg) of ~2.0 eV are developed for use in next-generation multijunction photovoltaic devices. This material system is of great interest for both space and concentrator photovoltaics due to its high bandgap, which enables the development of high-efficiency five-junction and six-junction devices and is also useful for solar cells operated at elevated temperatures. In this work, we explore the conditions for the Organometallic Vapor Phase Epitaxy (OMVPE) growth of AlGaInP and study their effects on cell performance. A ~2.0 eV AlGaInP solar cell is demonstrated with an open circuit voltage (VOC) of 1.59V, a bandgap-voltage offset (WOC) of 420mV, a fill factor (FF) of 88.0%, and an efficiency of 14.8%. These AlGaInP cells have attained a similar FF, WOC and internal quantum efficiency (IQE) to the best upright GaInP cells grown in our lab to date.

  16. P-doped strontium titanate grown using two target pulsed laser deposition for thin film solar cells

    NASA Astrophysics Data System (ADS)

    Man, Hamdi

    Thin-film solar cells made of Mg-doped SrTiO3 p-type absorbers are promising candidates for clean energy generation. This material shows p-type conductivity and also demonstrates reasonable absorption of light. In addition, p-type SrTiO3 can be deposited as thin films so that the cost can be lower than the competing methods. In this work, Mg-doped SrTiO3 (STO) thin-films were synthesized and analyzed in order to observe their potential to be employed as the base semiconductor in photovoltaic applications. Mg-doped STO thin-films were grown by using pulsed laser deposition (PLD) using a frequency quadrupled Yttrium Aluminum Garnet (YAG) laser and with a substrate that was heated by back surface absorption of infrared (IR) laser light. The samples were characterized using X-ray photoelectron spectroscopy (XPS) and it was observed that Mg atoms were doped successfully in the stoichiometry. Reflection high energy electron diffraction (RHEED) spectroscopy proved that the thin films were polycrystalline. Kelvin Probe work function measurements indicated that the work function of the films were 4.167 eV after annealing. UV/Vis Reflection spectroscopy showed that Mg-doped STO thin-films do not reflect significantly except in the ultraviolet region of the spectrum where the reflection percentage increased up to 80%. Self-doped STO thin-films, Indium Tin Oxide (ITO) thin films and stainless steel foil (SSF) were studied in order to observe their characteristics before employing them in Mg-doped STO based solar cells. Self-doped STO thin films were grown using PLD and the results showed that they are capable of serving as the n-type semiconductor in solar cell applications with oxygen vacancies in their structure and low reflectivity. Indium Tin Oxide thin-films grown by PLD system showed low 25-50 ?/square sheet resistance and very low reflection features. Finally, commercially available stainless steel foil substrates were excellent substrates for the inexpensive growth of

  17. Impact of batch, repeated-batch (with cell recycle and medium replacement) and continuous processes on the course and efficiency of aerobic thermophilic biodegradation of potato processing wastewater.

    PubMed

    Lasik, Małgorzata; Nowak, Jacek; Krzywonos, Małgorzata; Cibis, Edmund

    2010-05-01

    The aim of the study was to assess the course and efficiency of aerobic thermophilic treatment of a high-strength (COD=35gO(2)/l) effluent from potato processing. A comparative analysis was conducted of the treatment effects achieved using batch, repeated-batch (with cell recycle and medium replacement) and continuous treatment operations. The analysis consisted in (1) examining the extent of removal for the major parameters of the wastewater: COD, TOC, TN and TP (chemical oxygen demand, total organic carbon, total nitrogen and total phosphorus), and (2) determining the impact of oxygen deficit on the formation and assimilation of organic acids in the course of the three treatment operations. When use was made of the repeated-batch operation, the values of the COD and TOC removal rates were more than twice as high as those obtained with the continuous process, and more than five times as high as those obtained with the batch process.

  18. Constitutive expression of Campylobacter jejuni truncated hemoglobin CtrHb improves the growth of Escherichia coli cell under aerobic and anaerobic conditions.

    PubMed

    Yang, Jiang-Ke; Xiong, Wei; Xu, Li; Li, Jia; Zhao, Xiu-Ju

    2015-01-01

    Bacteria hemoglobin could bind to the oxygen, transfer it from the intracellular microenvironment to the respiration process and sustain the energy for the metabolism and reproduction of cells. Heterologous expression of bacteria hemoglobin gene could improve the capacity of the host on oxygen-capturing and allow it to grow even under microaerophilic condition. To develop a system based on hemoglobin to help bacteria cells overcome the oxygen shortage in fermentation, in this study, Campylobacter jejuni truncated hemoglobin (CtrHb) gene was synthesized and expressed under the control of constitutive expression promoters P2 and P(SPO1-II) in Escherichia coli. As showed by the growth curves of the two recombinants P2-CtrHb and P(SPO1-II)-CtrHb, constitutive expression of CtrHb improved cell growth under aerobic shaking-flasks, anaerobic capped-bottles and bioreactor conditions. According to the NMR analysis, this improvement might come from the expression of hemoglobin which could boost the metabolism of cells by supplying more oxygen to the respiratory chain processes. Through semi-quantitative RT-PCR and CO differential spectrum assays, we further discussed the connection between the growth patterns of the recombinants, the expression level of CtrHb and oxygen binding capacity of CtrHb in cells. Based on the growth patterns of these recombinants in bioreactor, a possible choice on different type of recombinants under specific fermentation conditions was also suggested in this study.

  19. Data Pre-Processing Method to Remove Interference of Gas Bubbles and Cell Clusters During Anaerobic and Aerobic Yeast Fermentations in a Stirred Tank Bioreactor

    NASA Astrophysics Data System (ADS)

    Princz, S.; Wenzel, U.; Miller, R.; Hessling, M.

    2014-11-01

    One aerobic and four anaerobic batch fermentations of the yeast Saccharomyces cerevisiae were conducted in a stirred bioreactor and monitored inline by NIR spectroscopy and a transflectance dip probe. From the acquired NIR spectra, chemometric partial least squares regression (PLSR) models for predicting biomass, glucose and ethanol were constructed. The spectra were directly measured in the fermentation broth and successfully inspected for adulteration using our novel data pre-processing method. These adulterations manifested as strong fluctuations in the shape and offset of the absorption spectra. They resulted from cells, cell clusters, or gas bubbles intercepting the optical path of the dip probe. In the proposed data pre-processing method, adulterated signals are removed by passing the time-scanned non-averaged spectra through two filter algorithms with a 5% quantile cutoff. The filtered spectra containing meaningful data are then averaged. A second step checks whether the whole time scan is analyzable. If true, the average is calculated and used to prepare the PLSR models. This new method distinctly improved the prediction results. To dissociate possible correlations between analyte concentrations, such as glucose and ethanol, the feeding analytes were alternately supplied at different concentrations (spiking) at the end of the four anaerobic fermentations. This procedure yielded low-error (anaerobic) PLSR models for predicting analyte concentrations of 0.31 g/l for biomass, 3.41 g/l for glucose, and 2.17 g/l for ethanol. The maximum concentrations were 14 g/l biomass, 167 g/l glucose, and 80 g/l ethanol. Data from the aerobic fermentation, carried out under high agitation and high aeration, were incorporated to realize combined PLSR models, which have not been previously reported to our knowledge.

  20. Optimizing aerobic conversion of glycerol to 3-hydroxypropionaldehyde

    SciTech Connect

    Slininger, P.J.; Bothast, R.J.

    1985-12-01

    Chemical oxidation of 3-hydroxypropionaldehyde (3-HPA) leads to acrylic acid, an industrially important polymerizable monomer currently derived from petroleum. As the availability of petroleum declines, 3-HPA may become attractive as a product to be obtained through fermentation of glycerol, a renewable resource. When cells of Klebsiella pneumoniae NRRL B-199 (ATCC 8724) were grown aerobically on a rich glycerol medium and then suspended in buffer supplemented with semicarbazide and glycerol, aerobic conversion of glycerol to 3-hydroxypropionaldehyde (3-HPA) ensued. Depending on conditions, 0.38 to 0.67 g of 3-HPA were formed per gram of glycerol consumed. This means that up to 83.8% of the carbon invested as glycerol could potentially be recovered as the target product, 3-HPA. Production of 3-HPA was sensitive to the age of cells harvested for resuspension and was nonexistent if cells were cultivated on glucose instead of glycerol as the sole carbon source. Compared with 24- and 72-h cells, 48-h cells produced 3-HPA at the highest rate and with the greatest yield. The cell biomass concentration present during the fermentation was never particularly critical to the 3-HPA yield, but initial fermentation rates and 3-HPA accumulation displayed a linear dependence on biomass concentration that faded when biomass exceeded 3 g/liter. Fermentation performance was a function of temperature, and an optimum initial specific 3-HPA productivity occurred at 32/sup 0/C, although the overall 3-HPA yield increased continuously within the 25 to 37/sup 0/C range studied. The pH optimum based on fermentation rate was different from that based on overall yield; 8 versus 7, respectively. Initial glycerol concentrations in the 20 to 50 g/liter range optimized initial 3-HPA productivity and yield.

  1. Surface-passivated GaAsP single-nanowire solar cells exceeding 10% efficiency grown on silicon.

    PubMed

    Holm, Jeppe V; Jørgensen, Henrik I; Krogstrup, Peter; Nygård, Jesper; Liu, Huiyun; Aagesen, Martin

    2013-01-01

    Continued development of high-efficiency multi-junction solar cells requires growth of lattice-mismatched materials. Today, the need for lattice matching both restricts the bandgap combinations available for multi-junctions solar cells and prohibits monolithic integration of high-efficiency III-V materials with low-cost silicon solar cells. The use of III-V nanowires is the only known method for circumventing this lattice-matching constraint, and therefore it is necessary to develop growth of nanowires with bandgaps >1.4 eV. Here we present the first gold-free gallium arsenide phosphide nanowires grown on silicon by means of direct epitaxial growth. We demonstrate that their bandgap can be controlled during growth and fabricate core-shell nanowire solar cells. We further demonstrate that surface passivation is of crucial importance to reach high efficiencies, and present a record efficiency of 10.2% for a core-shell single-nanowire solar cell.

  2. Dye-sensitized solar cells with vertically aligned TiO2 nanowire arrays grown on carbon fibers.

    PubMed

    Cai, Xin; Wu, Hongwei; Hou, Shaocong; Peng, Ming; Yu, Xiao; Zou, Dechun

    2014-02-01

    One-dimensional semiconductor TiO2 nanowires (TNWs) have received widespread attention from solar cell and related optoelectronics scientists. The controllable synthesis of ordered TNW arrays on arbitrary substrates would benefit both fundamental research and practical applications. Herein, vertically aligned TNW arrays in situ grown on carbon fiber (CF) substrates through a facile, controllable, and seed-assisted thermal process is presented. Also, hierarchical TiO2 -nanoparticle/TNW arrays were prepared that favor both the dye loading and depressed charge recombination of the CF/TNW photoanode. An impressive conversion efficiency of 2.48 % (under air mass 1.5 global illumination) and an apparent efficiency of 4.18 % (with a diffuse board) due to the 3D light harvesting of the wire solar cell were achieved. Moreover, efficient and inexpensive wire solar cells made from all-CF electrodes and completely flexible CF-based wire solar cells were demonstrated, taking into account actual application requirements. This work may provide an intriguing avenue for the pursuit of lightweight, cost-effective, and high-performance flexible/wearable solar cells.

  3. Antigenic Protein In Microgravity-Grown Human Mixed Mullerian Tumor (LN1) Cells Preserved In RNA Stabilizing Agent

    NASA Technical Reports Server (NTRS)

    Hammond, Dianne K.; Becker, Jeanne; Holubec, K.; Baker, T. L.; Love, J. E.

    2004-01-01

    Cells treated with RNAlater(TradeMark) have previously been shown to contain antigenic proteins that can be visualized using Western blot analysis. These proteins seem to be stable for several months when stored in RNA stabilizer at 4 C. Antigenic protein can be recovered from cells that have been processed using an Ambion RNAqueous(Registered TradeMark) kit to remove RNA. In this set of experiments, human mixed Mullerian tumor (LN1) cells grown on the International Space Station during Expedition 3 were examined for antigenic stability after removal of RNA. The cells were stored for three months in RNAlater(TradeMark) and RNA was extracted. The RNA filtrate Containing the protein was precipitated, washed, and suspended in buffer containing sodium dodecyl sulfate (SDS). Samples containing equal concentrations of protein were loaded onto SDS-polyacrylamide gels. Proteins were separated by electrophoresis and transferred by Western blot to polyvinylidene fluoride (PVDF) membrane. The Western blots were stained with an enhanced chemiluminescent ECL(Registered TradeMark)Plus detection kit (Amersham) and scanned using a Storm 840 gel image analyzer (Amersham, Molecular Dynamics). ImageQuant(Registered TradeMark)a software was used to quantify the densities of the protein bands. The ground control and flight LN1 cell samples showed a similar staining pattern over time with antibodies to vimentin, glyceraldehyde-3-phosphate dehydrogenase, and epithelial membrane antigens.

  4. Antigenic Protein In Microgravity-Grown Human Mixed Mullerian Tumor (LN1) Cells Preserved In RNA Stabilizing Agent

    NASA Technical Reports Server (NTRS)

    Hammond, Dianne K.; Becker, Jeanne; Elliott, T. F.; Holubec, K.; Baker, T. L.; Love, J. E.

    2004-01-01

    Cells treated with RNAlater(TradeMark) have previously been shown to contain antigenic proteins that can be visualized using Western blot analysis. These proteins seem to be stable for several months when stored in RNA stabilizer at 4 C. Antigenic protein can be recovered from cells that have been processed using an Ambion RNAqueous(Registered TradeMark) kit to remove RNA. In this set of experiments, human mixed Mullerian tumor (LNI) cells grown on the International Space Station during Expedition 3 were examined for antigenic stability after removal of RNA. The cells were stored for three months in RNAlater(TradeMark) and RNA was extracted. The RNA filtrate containing the protein was precipitated, washed, and suspended in buffer containing sodium dodecyl sulfate (SDS). Samples containing equal concentrations of protein were loaded onto SDS-polyacrylamide gels. Proteins were separated by electrophoresis and transferred by Western blot to polyvinylidene fluoride (PVDF) membrane. The Western blots were stained with an enhanced chemiluminescent ECL(Registered Trademark) Plus detection kit (Amersham) and scanned using a Storm 840 gel image analyzer (Amersham, Molecular Dynamics). ImageQuant(Registered TradeMark) software was used to quantify the densities of the protein bands. The ground control and flight LN1 cell samples showed a similar staining pattern over time with antibodies to vimentin, glyceraldehyde-3-phosphate dehydrogenase, and epithelial membrane antigens.

  5. N-Linked glycans on dengue viruses grown in mammalian and insect cells

    PubMed Central

    Hacker, Kari; White, Laura; de Silva, Aravinda M.

    2009-01-01

    This study compared the ability of mosquito and mammalian cell-derived dengue virus (DENV) to infect human dendritic cell-specific ICAM3-grabbing non-integrin (DC-SIGN)-expressing cells and characterized the structure of envelope (E) protein N-linked glycans on DENV derived from the two cell types. DENVs derived from both cell types were equally effective at infecting DC-SIGN-expressing human monocytes and dendritic cells. The N-linked glycans on mosquito cell-derived virus were a mix of high-mannose and paucimannose glycans. In virus derived from mammalian cells, the N-linked glycans were a mix of high-mannose and complex glycans. These results indicate that N-linked glycans are incompletely processed during DENV egress from cells, resulting in high-mannose glycans on viruses derived from both cell types. Studies with full-length and truncated E protein demonstrated that incomplete processing was most likely a result of the poor accessibility of glycans on the membrane-anchored protein. PMID:19494052

  6. Complete degradation of the azo dye Acid Orange-7 and bioelectricity generation in an integrated microbial fuel cell, aerobic two-stage bioreactor system in continuous flow mode at ambient temperature.

    PubMed

    Fernando, Eustace; Keshavarz, Taj; Kyazze, Godfrey

    2014-03-01

    In this study, the commercially used model azo dye Acid Orange-7 (AO-7) was fully degraded into less toxic intermediates using an integrated microbial fuel cell (MFC) and aerobic bioreactor system. The integrated bioreactor system was operated at ambient temperature and continuous-flow mode. AO-7 loading rate was varied during experiments from 70gm(-3)day(-1) to 210gm(-3)day(-1). Colour and soluble COD removal rates reached>90% under all AO-7 loading rates. The MFC treatment stage prompted AO-7 to undergo reductive degradation into its constituent aromatic amines. HPLC-MS analysis of metabolite extracts from the aerobic stage of the bioreactor system indicated further oxidative degradation of the resulting aromatic amines into simpler compounds. Bioluminescence based Vibrio fischeri ecotoxicity testing demonstrated that aerobic stage effluent exhibited toxicity reductions of approximately fivefold and ten-fold respectively compared to the dye wastewater influent and MFC-stage effluent.

  7. Positioning effects on quantum dot solar cells grown by molecular beam epitaxy

    SciTech Connect

    Zhou, D.; Sharma, G.; Fimland, B. O.; Vullum, P. E.; Thomassen, S. F.; Holmestad, R.; Reenaas, T. W.

    2010-02-22

    We report current-voltage and spectral response characteristics of high density InAs/GaAs quantum dot (QD) solar cells with different positions where dots are located. The short circuit current density (J{sub sc}), open circuit voltage (V{sub oc}), and external quantum efficiency of these cells under air mass 1.5 are presented and compared with a GaAs reference cell. An extended photoresponse in contrast to the GaAs reference cell was confirmed for all these cells. The effect of inserting QD layers into emitter and base region on device performance is shown. The J{sub sc} is reduced, while the V{sub oc} is maintained. The cell with QDs located toward the base side shows better performance, confirmed by both current-voltage and spectral response measurements.

  8. Effect of Hypergravity on Localization Calcium Ions in Plant Cells Grown in Vivo and in Vitro

    NASA Astrophysics Data System (ADS)

    Nedukha, Olena

    Using plant callus tissues and Arabidopsis thaliana plants as model systems we have been investigated the effect of hypergravity on the localization and relative content of calcium ions in photosynthesizing cells. The tobacco callus cells in log stage of growth and mesophyll cells from developed A. thaliana leaves were used in the experiments. Plant samples were exposed to hypergravity at 6.5 g, 10g and 14 g for 15-60 min. After centrifugation, dye Fluo-4 was loaded in the control leaves and the centrifuged samples by the standard cytochemical method. Observation of calcium fluorescence was carried out with a laser confocal microscope LSM 5 Pascal at the excitation wave 488 nm (by the argon laser), at emission wavelength 516 nm. The data of the calcium ion distribution and quantification in cells were obtained using software "Pascal" (Carl Zeiss). The effect of hypergravity on redistribution of calcium ions in plant cells has been established. This effect is depended from exposure time and from the value of hypergravity. The cells cultivated in vitro is showed fast response to hypergravity influence. Plasmolysis cells and calcium domains formation have been observed in most of callus cells. This influence was like to that, which was wrote in Funaria hygrometrica protonema cells after 8.5 g influence (Sytnik et al., 1984). Leaf cells of A. thaliana were of less responsively to hypergravity than callus cells. Sytnik K, Kordyum E, Nedukha O. et al. 1984. Plant Cell Under Change of Geophysical Factors. Kiev: Naukova Dumka, 1-134 p.

  9. The density of apical cells of dark-grown protonemata of the moss Ceratodon purpureus

    NASA Technical Reports Server (NTRS)

    Schwuchow, J. M.; Kern, V. D.; Wagner, T.; Sack, F. D.

    2000-01-01

    Determinations of plant or algal cell density (cell mass divided by volume) have rarely accounted for the extracellular matrix or shrinkage during isolation. Three techniques were used to indirectly estimate the density of intact apical cells from protonemata of the moss Ceratodon purpureus. First, the volume fraction of each cell component was determined by stereology, and published values for component density were used to extrapolate to the entire cell. Second, protonemal tips were immersed in bovine serum albumin solutions of different densities, and then the equilibrium density was corrected for the mass of the cell wall. Third, apical cell protoplasts were centrifuged in low-osmolarity gradients, and values were corrected for shrinkage during protoplast isolation. Values from centrifugation (1.004 to 1.015 g/cm3) were considerably lower than from other methods (1.046 to 1.085 g/cm3). This work appears to provide the first corrected estimates of the density of any plant cell. It also documents a method for the isolation of protoplasts specifically from apical cells of protonemal filaments.

  10. Method of measuring nitric oxide release by vascular endothelial cells grown in microfluidic channels

    NASA Astrophysics Data System (ADS)

    Hosseinpour, S.; Liu, A. C.; Barakat, A. I.; Choy, J. C.; Gray, B. L.

    2014-03-01

    In this paper, a simple and versatile method is presented which enables detection of nitric oxide (NO) released from vascular endothelial cells (ECs) cultured in microfluidic structures. The culturing system and NO measurement method allow cell shape to be controlled in a non-invasive manner using microfluidic structures while NO release is monitored for cell shape versus function studies. The culturing system consists of arrays of polydimethylsiloxane (PDMS) fluidic channels 120 micrometers in depth and ranging from 100 micrometers to 3 mm in width. The number of channels in each array is varied to yield a constant cell culture surface area (75 mm2) independent of channel width. The channel surfaces are collagen-coated and ECs are cultured to confluence within the channels. A cell scraper is then used to scrape extraneous cells cultured between channels, and NO measurements are made 18 to 24 hours later. A chemiluminescence-based sensor system (NOA 280i, Sievers NO Analyzer) is utilized to measure sample NO. Initial results indicate that NO concentrations can be measured from different microfluidic channel-containing samples using this method. It is shown that there is no significant difference in NO concentration derived from channels of different widths even though the degree of cell elongation varies due to physical constraint by microfluidic channel walls. However, cells treated with TNFα release more NO than untreated cells in fluidic channels, which is comparable to the function of ECs cultured in conventional culturing systems such as culturing dishes.

  11. Aerobic Degradation of N-Methyl-4-Nitroaniline (MNA) by Pseudomonas sp. Strain FK357 Isolated from Soil

    PubMed Central

    Khan, Fazlurrahman; Vyas, Bhawna; Pal, Deepika; Cameotra, Swaranjit Singh

    2013-01-01

    N-Methyl-4-nitroaniline (MNA) is used as an additive to lower the melting temperature of energetic materials in the synthesis of insensitive explosives. Although the biotransformation of MNA under anaerobic condition has been reported, its aerobic microbial degradation has not been documented yet. A soil microcosms study showed the efficient aerobic degradation of MNA by the inhabitant soil microorganisms. An aerobic bacterium, Pseudomonas sp. strain FK357, able to utilize MNA as the sole carbon, nitrogen, and energy source, was isolated from soil microcosms. HPLC and GC-MS analysis of the samples obtained from growth and resting cell studies showed the formation of 4-nitroaniline (4-NA), 4-aminophenol (4-AP), and 1, 2, 4-benzenetriol (BT) as major metabolic intermediates in the MNA degradation pathway. Enzymatic assay carried out on cell-free lysates of MNA grown cells confirmed N-demethylation reaction is the first step of MNA degradation with the formation of 4-NA and formaldehyde products. Flavin-dependent transformation of 4-NA to 4-AP in cell extracts demonstrated that the second step of MNA degradation is a monooxygenation. Furthermore, conversion of 4-AP to BT by MNA grown cells indicates the involvement of oxidative deamination (release of NH2 substituent) reaction in third step of MNA degradation. Subsequent degradation of BT occurs by the action of benzenetriol 1, 2-dioxygenase as reported for the degradation of 4-nitrophenol. This is the first report on aerobic degradation of MNA by a single bacterium along with elucidation of metabolic pathway. PMID:24116023

  12. Thyrotropin dependent and independent thyroid cell lines selected from FRTL-5 derived tumors grown in nude mice

    SciTech Connect

    Ossendorp, F.A.; Bruning, P.F.; Schuuring, E.M.; Van Den Brink, J.A.; van der Heide, D.; De Vijlder, J.J.; De Bruin, T.W. )

    1990-07-01

    FRTL-5 cells were used to set up a thyroid tumor model system in C3H nu/nu mice. FRTL-5 tumors could be grown in nude mice provided serum TSH levels were elevated. Persistent TSH elevation was obtained by administration of Na131I, rendering the mice hypothyroid. After 4 weeks FRTL-5 cells were injected sc resulting in tumor growth within 2 weeks in eight out of eight mice. Although the tumors showed an apparently undifferentiated histology, lacking normal follicular structures, they were functional since the tumors were capable of concentrating (131)iodine, as demonstrated by nuclear imaging. From one of the tumors a new cell line was isolated (FRTL-5/T) that, like the parental FRTL-5 cell line, was TSH dependent for growth. In a control group of six euthyroid nude mice FRTL-5 tumor growth could not be obtained with one exception. After 3 months one animal developed a small tumor that grew rapidly thereafter. This tumor was easily transplantable in other euthyroid nude mice, showed an undifferentiated histology, and was nonfunctional, as it could not concentrate (131)iodine. From this tumor two cell lines were derived: one cultured in the presence of TSH (FRTL-5/TP) and one in the absence of TSH (FRTL-5/TA). The cell lines were analyzed for TSH responsive functions and TSH receptor expression. Responsiveness to TSH in FRTL-5/T and the parental FRTL-5 cell line were similar for most thyroid specific functions tested. However, FRTL-5/T was less sensitive than FRTL-5 for TSH induced (3H)thymidine incorporation. Both cell lines had two classes of TSH binding sites with high and low affinity respectively. FRTL-5/TP and FRTL-5/TA were both able to grow in TSH free medium and were nonresponsive to TSH in vitro, as tested for (3H)thymidine and (3H)uridine incorporation, iodine uptake, thyroglobulin iodination, and thyroglobulin secretion.

  13. Gene expression patterns in granulosa cells and oocytes at various stages of follicle development as well as in in vitro grown oocyte-and-granulosa cell complexes.

    PubMed

    Munakata, Yasuhisa; Kawahara-Miki, Ryoka; Shiratsuki, Shogo; Tasaki, Hidetaka; Itami, Nobuhiko; Shirasuna, Koumei; Kuwayama, Takehito; Iwata, Hisataka

    2016-08-25

    Follicle development is accompanied by proliferation of granulosa cells and increasing oocyte size. To obtain high-quality oocytes in vitro, it is important to understand the processes that occur in oocytes and granulosa cells during follicle development and the differences between in vivo and in vitro follicle development. In the present study, oocytes and granulosa cells were collected from early antral follicles (EAFs, 0.5-0.7 mm in diameter), small antral follicles (SAFs, 1-3 mm in diameter), large antral follicles (LAFs, 3-7 mm in diameter), and in vitro grown oocyte-and-granulosa cell complexes (OGCs), which were cultured for 14 days after collection from EAFs. Gene expression was analyzed comprehensively using the next-generation sequencing technology. We found top upstream regulators during the in vivo follicle development and compared them with those in in vitro developed OGCs. The comparison revealed that HIF1 is among the top regulators during both in vivo and in vitro development of OGCs. In addition, we found that HIF1-mediated upregulation of glycolysis in granulosa cells is important for the growth of OGCs, but the cellular metabolism differs between in vitro and in vivo grown OGCs. Furthermore, on the basis of comparison of upstream regulators between in vivo and in vitro development of OGCs, we believe that low expression levels of FLT1 (VEGFA receptor), SPP1, and PCSK6 can be considered causal factors of the suboptimal development under in vitro culture conditions.

  14. Gene expression patterns in granulosa cells and oocytes at various stages of follicle development as well as in in vitro grown oocyte-and-granulosa cell complexes

    PubMed Central

    MUNAKATA, Yasuhisa; KAWAHARA-MIKI, Ryoka; SHIRATSUKI, Shogo; TASAKI, Hidetaka; ITAMI, Nobuhiko; SHIRASUNA, Koumei; KUWAYAMA, Takehito; IWATA, Hisataka

    2016-01-01

    Follicle development is accompanied by proliferation of granulosa cells and increasing oocyte size. To obtain high-quality oocytes in vitro, it is important to understand the processes that occur in oocytes and granulosa cells during follicle development and the differences between in vivo and in vitro follicle development. In the present study, oocytes and granulosa cells were collected from early antral follicles (EAFs, 0.5–0.7 mm in diameter), small antral follicles (SAFs, 1–3 mm in diameter), large antral follicles (LAFs, 3–7 mm in diameter), and in vitro grown oocyte-and-granulosa cell complexes (OGCs), which were cultured for 14 days after collection from EAFs. Gene expression was analyzed comprehensively using the next-generation sequencing technology. We found top upstream regulators during the in vivo follicle development and compared them with those in in vitro developed OGCs. The comparison revealed that HIF1 is among the top regulators during both in vivo and in vitro development of OGCs. In addition, we found that HIF1-mediated upregulation of glycolysis in granulosa cells is important for the growth of OGCs, but the cellular metabolism differs between in vitro and in vivo grown OGCs. Furthermore, on the basis of comparison of upstream regulators between in vivo and in vitro development of OGCs, we believe that low expression levels of FLT1 (VEGFA receptor), SPP1, and PCSK6 can be considered causal factors of the suboptimal development under in vitro culture conditions. PMID:27108636

  15. Novel role of NOX in supporting aerobic glycolysis in cancer cells with mitochondrial dysfunction and as a potential target for cancer therapy.

    PubMed

    Lu, Weiqin; Hu, Yumin; Chen, Gang; Chen, Zhao; Zhang, Hui; Wang, Feng; Feng, Li; Pelicano, Helene; Wang, Hua; Keating, Michael J; Liu, Jinsong; McKeehan, Wallace; Wang, Huamin; Luo, Yongde; Huang, Peng

    2012-01-01

    Elevated aerobic glycolysis in cancer cells (the Warburg effect) may be attributed to respiration injury or mitochondrial dysfunction, but the underlying mechanisms and therapeutic significance remain elusive. Here we report that induction of mitochondrial respiratory defect by tetracycline-controlled expression of a dominant negative form of DNA polymerase γ causes a metabolic shift from oxidative phosphorylation to glycolysis and increases ROS generation. We show that upregulation of NOX is critical to support the elevated glycolysis by providing additional NAD+. The upregulation of NOX is also consistently observed in cancer cells with compromised mitochondria due to the activation of oncogenic Ras or loss of p53, and in primary pancreatic cancer tissues. Suppression of NOX by chemical inhibition or genetic knockdown of gene expression selectively impacts cancer cells with mitochondrial dysfunction, leading to a decrease in cellular glycolysis, a loss of cell viability, and inhibition of cancer growth in vivo. Our study reveals a previously unrecognized function of NOX in cancer metabolism and suggests that NOX is a potential novel target for cancer treatment.

  16. Changes in levels of cell wall constituents in wheat seedlings grown under continuous hypergravity conditions

    NASA Astrophysics Data System (ADS)

    Wakabayashi, K.; Soga, K.; Kamisaka, S.; Hoson, T.

    Effects of continuous hypergravity stimuli on the amounts and composition of cell wall constituents were investigated in wheat shoots. Hypergravity (300 g) treatment for three days after germination increased the net amount of cell wall polysaccharides such as hemicellulose and cellulose, but reduced the shoot elongation. As a result, the amount of cell wall polysaccharides per unit length of shoot increased under hypergravity. The hemicellulose fraction contained polysaccharides in the middle and low molecular mass range (5 kDa-1 MDa) and increased in response to hypergravity. Also, the amounts of arabinose (Ara) and xylose (Xyl), the major sugar components of the hemicellulose fraction, increased under hypergravity conditions. In addition to wall polysaccharides, hypergravity increased the amounts of cell wall-bound phenolic acids, such as ferulic acid (FA) and diferulic acid (DFA). Furthermore, the activity of phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) was enhanced under hypergravity conditions. These results suggest that continuous hypergravity stimulates the synthesis of cell wall constituents, especially hemicellulosic arabinoxylans and cell wall-bound FA and DFA in wheat shoots. The increased PAL activity may promote the formation of FA and DFA. These changes in cell wall architecture may be involved in making rigid and tough cell walls under hypergravity conditions and thereby contribute to the ability of plant to sustain their structures against gravitational stimuli.

  17. Advanced APCVD-processes for high-temperature grown crystalline silicon thin film solar cells.

    PubMed

    Driessen, Marion; Merkel, Benjamin; Reber, Stefan

    2011-09-01

    Crystalline silicon thin film (cSiTF) solar cells based on the epitaxial wafer-equivalent (EpiWE) concept combine advantages of wafer-based and thin film silicon solar cells. In this paper two processes beyond the standard process sequence for cSiTF cell fabrication are described. The first provides an alternative to wet chemical saw damage removal by chemical vapor etching (CVE) with hydrogen chloride in-situ prior to epitaxial deposition. This application decreases the number of process and handling steps. Solar cells fabricated with different etching processes achieved efficiencies up to 14.7%. 1300 degrees C etching temperature led to better cell results than 1200 degrees C. The second investigated process aims for an improvement of cell efficiency by implementation of a reflecting interlayer between substrate and active solar cell. Some characteristics of epitaxial lateral overgrowth (ELO) of a patterned silicon dioxide film in a lab-type reactor constructed at Fraunhofer ISE are described and first solar cell results are presented.

  18. Biguanide-induced mitochondrial dysfunction yields increased lactate production and cytotoxicity of aerobically-poised HepG2 cells and human hepatocytes in vitro

    SciTech Connect

    Dykens, James A. Jamieson, Joseph; Marroquin, Lisa; Nadanaciva, Sashi; Billis, Puja A.; Will, Yvonne

    2008-12-01

    As a class, the biguanides induce lactic acidosis, a hallmark of mitochondrial impairment. To assess potential mitochondrial impairment, we evaluated the effects of metformin, buformin and phenformin on: 1) viability of HepG2 cells grown in galactose, 2) respiration by isolated mitochondria, 3) metabolic poise of HepG2 and primary human hepatocytes, 4) activities of immunocaptured respiratory complexes, and 5) mitochondrial membrane potential and redox status in primary human hepatocytes. Phenformin was the most cytotoxic of the three with buformin showing moderate toxicity, and metformin toxicity only at mM concentrations. Importantly, HepG2 cells grown in galactose are markedly more susceptible to biguanide toxicity compared to cells grown in glucose, indicating mitochondrial toxicity as a primary mode of action. The same rank order of potency was observed for isolated mitochondrial respiration where preincubation (40 min) exacerbated respiratory impairment, and was required to reveal inhibition by metformin, suggesting intramitochondrial bio-accumulation. Metabolic profiling of intact cells corroborated respiratory inhibition, but also revealed compensatory increases in lactate production from accelerated glycolysis. High (mM) concentrations of the drugs were needed to inhibit immunocaptured respiratory complexes, supporting the contention that bioaccumulation is involved. The same rank order was found when monitoring mitochondrial membrane potential, ROS production, and glutathione levels in primary human hepatocytes. In toto, these data indicate that biguanide-induced lactic acidosis can be attributed to acceleration of glycolysis in response to mitochondrial impairment. Indeed, the desired clinical outcome, viz., decreased blood glucose, could be due to increased glucose uptake and glycolytic flux in response to drug-induced mitochondrial dysfunction.

  19. Development of an in situ detachment protocol of Vero cells grown on Cytodex1 microcarriers under animal component-free conditions in stirred bioreactor.

    PubMed

    Rourou, Samia; Riahi, Nesrine; Majoul, Samy; Trabelsi, Khaled; Kallel, Héla

    2013-08-01

    Subcultivation of Vero cells grown in a proprietary animal component-free medium named IPT-AFM, on microcarriers, was studied. TrypLE Select, a non-animal-derived protease, was used as an alternative to trypsin for cell passaging. We first studied the effect of increasing concentrations of TrypLE Select toward cell growth and then studied the inactivation of the protease using either soybean trypsin inhibitor (STI) or the soy hydrolysate Hypep 1510, in six-well plates. Data showed that cell growth was impaired by residual level of TrypLE Select; STI was identified as an efficient agent to neutralize this effect. To restore cell growth and inactivate TrypLE Select, STI should be added to the medium at least at 0.2 g L(-1). Cells were also grown in spinner flask on 2 g L(-1) Cytodex1 in IPT-AFM. In these conditions, the cell detachment yield was equal to 78 ± 8 %. Furthermore, cells exhibited a typical growth profile when using the dislodged cells to seed a new culture. A cell detachment yield of 70 ± 19 % was also achieved when the cells were grown in a 2-L stirred bioreactor in IPT-AFM, on 3 g L(-1) Cytodex1. This protocol can be of great interest to scale-up the process of Vero cells cultivation in IPT-AFM on Cytodex1 from one stirred bioreactor culture to another.

  20. Induction of E. coli oh8Gua endonuclease by oxidative stress: its significance in aerobic life.

    PubMed

    Kim, H S; Park, Y W; Kasai, H; Nishimura, S; Park, C W; Choi, K H; Chung, M H

    1996-06-12

    The induction of 8-hydroxyguanine (oh8Gua) endonuclease, a DNA repair enzyme for an oxidatively modified guanine, oh8Gua was studied in various growth conditions in Escherichia coli (AB1157). Anaerobically grown E. coli were found to have a very low activity of this enzyme while aerobically grown cells showed activity about 20 times that of the anaerobic level. Under the same condition, superoxide dismutase (SOD) showed about 6-fold increase in activity. A shift in growth conditions from anaerobic to aerobic resulted in rapid induction of this enzyme, and this induction was blocked (but not completely) by chloramphenicol. It is indicated that molecular oxygen is an effective stimulator to the induction of this enzyme and its induction depends partly on protein synthesis. Superoxide-producing compounds such as paraquat and menadione also increased the activity of endonuclease as well as SOD, but H2O2 showed no effect. Thus, superoxides are also implied as a stimulator. In contrast, hyperoxia induced only SOD not the endonuclease. This induction of the endonuclease by hyperoxia was only observed in a SOD-deficient strain (QC774). The aerobic activity of the endonuclease in QC774 was the same as that of wild types (AB1157, GC4468). It is implied that the responsiveness of oh8Gua endonuclease to superoxides is less sensitive than that of SOD. The endonuclease was also induced by a temperature shift from 30 to 43 degrees C and treatment with nalidixic acid. Among the stimuli used, molecular oxygen seems to be most effective for its induction. The inducible nature of this enzyme will serve as an important mechanism for the protection of oxidative DNA damage in the aerobic environment.

  1. Transcriptome profiling in Arabidopsis inflorescence stems grown under hypergravity in terms of cell walls and plant hormones

    NASA Astrophysics Data System (ADS)

    Tamaoki, D.; Karahara, I.; Nishiuchi, T.; De Oliveira, S.; Schreiber, L.; Wakasugi, T.; Yamada, K.; Yamaguchi, K.; Kamisaka, S.

    2009-07-01

    Land plants rely on lignified secondary cell walls in supporting their body weight on the Earth. Although gravity influences the formation of the secondary cell walls, the regulatory mechanism of their formation by gravity is not yet understood. We carried out a comprehensive analysis of gene expression in inflorescence stems of Arabidopsis thaliana L. using microarray (22 K) to identify genes whose expression is modulated under hypergravity condition (300 g). Total RNA was isolated from the basal region of inflorescence stems of plants grown for 24 h at 300 g or 1 g. Microarray analysis showed that hypergravity up-regulated the expression of 403 genes to more than 2-fold. Hypergravity up-regulated the genes responsible for the biosynthesis or modification of cell wall components such as lignin, xyloglucan, pectin and structural proteins. In addition, hypergravity altered the expression of genes related to the biosynthesis of plant hormones such as auxin and ethylene and that of genes encoding hormone-responsive proteins. Our transcriptome profiling indicates that hypergravity influences the formation of secondary cell walls by modulating the pattern of gene expression, and that auxin and/or ethylene play an important role in signaling hypergravity stimulus.

  2. Identification of an anticancer compound against HT-29 cells from Phellinus linteus grown on germinated brown rice

    PubMed Central

    Jeon, Tae-Il; Jung, Chang-Hwa; Cho, Jeong-Yong; Park, Dong Ki; Moon, Jae-Hak

    2013-01-01

    Objective To isolate and identify the anticancer compound against proliferation of human colon cancer cells from ethyl acetate (EtOAC) extract of Phellinus linteus grown on germinated brown rice (PB). Methods EtOAC extract of PB was partitioned with n-hexane, EtOAC, and water-saturated n-butanol. Anticancer compound of n-hexane layer was isolated and identified by HPLC and NMR, respectively. Cytotoxicity against HT-29 cells was tested by SRB assay. Results The n-hexane layer obtained after solvent fractionation of PB EtOAC extracts showed a potent anticancer activity against the HT-29 cell line. Atractylenolide I, a eudesmane-type sesquiterpene lactone, a major anticancer substance of PB, was isolated from the n-hexane layer by silica gel column chromatography and preparative-HPLC. This structure was elucidated by one- and two-dimensional NMR spectroscopic data. Atractylenolide I has not been reported in mushrooms or rice as of yet. The isolated compound dose-dependently inhibited the growth of HT-29 human colon cancer cells. Conclusions Atractylenolide I might contribute to the anticancer effect of PB. PMID:24075343

  3. Scale-up of Agrobacterium-mediated transient protein expression in bioreactor-grown Nicotiana glutinosa plant cell suspension culture.

    PubMed

    O'Neill, Kristin M; Larsen, Jeffrey S; Curtis, Wayne R

    2008-01-01

    The reporter gene beta-glucuronidase was transiently expressed in a 51-L bioreactor-grown plant cell suspension culture of Nicotiana glutinosa at a yield of approximately 1.1 mg through co-culture with an auxotrophic strain of Agrobacterium tumefaciens. The three order of magnitude scale-up involved the investigation of factors contributing to transient expression including the timing of Agrobacterium inoculation relative to the plant cell growth phase, plant tissue culture hormonal triggers and plant cell cycle synchronization. The co-culture process was simplified to facilitate implementation in a pilot-scale bioreactor. At the shake flask scale it was determined that elevated concentrations of oxygen in the headspace were detrimental to transient expression levels and the addition of acetosyringone to the co-culture had a negligible effect. The bacterial preparation process was also streamlined, permitting the direct transfer of the Agrobacterium culture from a bench-scale fermentor to the pilot-scale plant cell culture bioreactor. Increasing expression levels and overcoming batch-to-batch variability despite extensive procedure systemization remain the major technical hurdles.

  4. Tolerance of Pseudomonas pseudoalcaligenes KF707 to metals, polychlorobiphenyls and chlorobenzoates: effects on chemotaxis-, biofilm- and planktonic-grown cells.

    PubMed

    Tremaroli, Valentina; Vacchi Suzzi, Caterina; Fedi, Stefano; Ceri, Howard; Zannoni, Davide; Turner, Raymond J

    2010-11-01

    Pseudomonas pseudoalcaligenes KF707 is a polychlorinated biphenyls (PCBs) degrader, also tolerant to several toxic metals and metalloids. The work presented here examines for the first time the chemotactic response of P. pseudoalcaligenes KF707 to biphenyl and intermediates of the PCB biodegradation pathway in the presence and absence of metals. Chemotaxis analyses showed that biphenyl, benzoic acid and chlorobenzoic acids acted as chemoattractants for KF707 cells and that metal cations such as Ni(2+) and Cu(2+) strongly affected the chemotactic response. Toxicity profiles of various metals on KF707 cells grown on succinate or biphenyl as planktonic and biofilm were determined both in the presence and in the absence of PCBs. Notably, KF707 cells from both biofilms and planktonic cultures were tolerant to high amounts (up to 0.5 g L(-1)) of Aroclor 1242, a commercial mixture of PCBs. Together, the data show that KF707 cells are chemotactic and can form a biofilm in the presence of Aroclor 1242 and specific metals. These findings provide new perspectives on the effectiveness of using PCB-degrading bacterial strains in bioremediation strategies of metal-co-contaminated sites.

  5. Effects of substrate conductivity on cell morphogenesis and proliferation using tailored, atomic layer deposition-grown ZnO thin films

    PubMed Central

    Choi, Won Jin; Jung, Jongjin; Lee, Sujin; Chung, Yoon Jang; Yang, Cheol-Soo; Lee, Young Kuk; Lee, You-Seop; Park, Joung Kyu; Ko, Hyuk Wan; Lee, Jeong-O

    2015-01-01

    We demonstrate that ZnO films grown by atomic layer deposition (ALD) can be employed as a substrate to explore the effects of electrical conductivity on cell adhesion, proliferation, and morphogenesis. ZnO substrates with precisely tunable electrical conductivity were fabricated on glass substrates using ALD deposition. The electrical conductivity of the film increased linearly with increasing duration of the ZnO deposition cycle (thickness), whereas other physical characteristics, such as surface energy and roughness, tended to saturate at a certain value. Differences in conductivity dramatically affected the behavior of SF295 glioblastoma cells grown on ZnO films, with high conductivity (thick) ZnO films causing growth arrest and producing SF295 cell morphologies distinct from those cultured on insulating substrates. Based on simple electrostatic calculations, we propose that cells grown on highly conductive substrates may strongly adhere to the substrate without focal-adhesion complex formation, owing to the enhanced electrostatic interaction between cells and the substrate. Thus, the inactivation of focal adhesions leads to cell proliferation arrest. Taken together, the work presented here confirms that substrates with high conductivity disturb the cell-substrate interaction, producing cascading effects on cellular morphogenesis and disrupting proliferation, and suggests that ALD-grown ZnO offers a single-variable method for uniquely tailoring conductivity. PMID:25897486

  6. Effects of Aerobic Growth on the Fatty Acid and Hydrocarbon Compositions of Geobacter bemidjiensis Bem(T).

    PubMed

    Ueno, Akio; Shimizu, Satoru; Hashimoto, Mikako; Adachi, Takumi; Matsushita, Takako; Okuyama, Hidetoshi; Yoshida, Kiyohito

    2017-01-01

    Geobacter spp., regarded as strict anaerobes, have been reported to grow under aerobic conditions. To elucidate the role of fatty acids in aerobiosis of Geobacter spp., we studied the effect of aerobiosis on fatty acid composition and turnover in G. bemidjiensis Bem(T). G. bemidjiensis Bem(T) was grown under the following different culture conditions: anaerobic culture for 4 days (type 1) and type 1 culture followed by 2-day anaerobic (type 2) or aerobic culture (anaerobic-to-aerobic shift; type 3). The mean cell weight of the type 3 culture was approximately 2.5-fold greater than that of type 1 and 2 cultures. The fatty acid methyl ester and hydrocarbon fraction contained hexadecanoic (16:0), 9-cis-hexadecenoic [16:1(9c)], tetradecanoic (14:0), tetradecenoic [14:1(7c)] acids, hentriacontanonaene, and hopanoids, but not long-chain polyunsaturated fatty acids. The type 3 culture contained higher levels of 14:0 and 14:1(7c) and lower levels of 16:0 and 16:1(9c) compared with type 1 and 2 cultures. The weight ratio of extracted lipid per dry cell was lower in the type 3 culture than in the type 1 and 2 cultures. We concluded that anaerobically-grown G. bemidjiensis Bem(T) followed by aerobiosis were enhanced in growth, fatty acid turnover, and de novo fatty acid synthesis.

  7. Promotion of glucose utilization by insulin enhances granulosa cell proliferation and developmental competence of porcine oocyte grown in vitro.

    PubMed

    Itami, Nobuhiko; Munakata, Yasuhisa; Shirasuna, Koumei; Kuwayama, Takehito; Iwata, Hisataka

    2017-02-01

    In vitro culture of the oocyte granulosa cell complexes (OGCs) from early antral follicles (EAFs) shows granulosa cell (GC) proliferation, but to a lesser extent than that observed in vivo during follicle development. As the number of GCs closely relates to energy sufficiency of the oocytes, enhancement of GC proliferation influences oocyte development. GC proliferation depends on glycolysis and insulin-mediated AKT/mTOR signaling pathway; therefore, addition of culture medium containing insulin and glucose may potentially promote GC proliferation and hence improve oocyte development. In the present study, we assessed the effect of exogenous insulin and glucose concentration on GC proliferation and oocyte energy status as well as developmental abilities of porcine oocytes grown in vitro. In the presence of 5.5 mM of glucose (Low), a comparison of 10 versus 20 μg/ml insulin showed that high insulin enhanced GC proliferation but exhausted glucose from the medium, which resulted in low energy status including lipid and adenosine triphosphate of the oocyte. Whereas, in the presence of 20 μg/ml insulin, medium with 11 mM glucose (High) enhanced GC proliferation and oocyte energy status as well as developmental ability up to the blastocyst stage. Considering that there was no difference in OGCs development observed with medium (10 μg/ml insulin) containing 5.5 versus 11 mM glucose, we concluded that the combination of high insulin and glucose enhanced GC proliferation and energy status of oocytes as well as the developmental ability of the oocytes grown in vitro.

  8. Changes in cell wall architecture of wheat coleoptiles grown under continuous hypergravity conditions

    NASA Astrophysics Data System (ADS)

    Wakabayashi, K.; Soga, K.; Kamisaka, S.; Hoson, T.

    Modifications of cell wall structure of wheat coleoptiles in response to continuous hypergravity (300 g) treatment were investigated. Length of coleoptiles exposed to hypergravity for 2-4 days from germination stage was 60-70% of that of 1 g control. The net amounts of cell wall polysaccharides, such as hemicellulose and cellulose, of hypergravity-treated coleoptiles increased as much as those of 1 g control coleoptiles during the incubation period. As a result, the levels of cell wall polysaccharides per unit length of coleoptile, which mean the thickness of cell walls, largely increased under hypergravity conditions. Particularly, the amounts of hemicellulosic polymers with middle molecular mass (0.2-1 MDa) largely increased from day 2 to 3 under hypergravity conditions. The major sugar components of the hemicellulose fraction are arabinose, xylose and glucose. The ratios of arabinose and xylose to glucose were higher in hypergravity-treated coleoptiles than in control coleoptiles. The fractionation of hemicellulosic polymers into the neutral and acidic polymers by the anion-exchange column showed that the levels of acidic polymers (mainly composed of arabinoxylans) in cell walls of hypergravity-treated coleoptiles were higher than those of control coleoptiles. In addition to wall polysaccharides, the amounts of cell wall-bound phenolics, such as ferulic acid and diferulic acid, substantially increased during the incubation period both in 1 g control and hypergravity-treated coleoptiles. Especially, the levels of diferulic acid which cross-links hemicellulosic polymers were higher in hypergravity-treated coleoptiles than in control coleoptiles during the incubation period. These results suggest that hypergravity stimuli from the germination stage bias the type of synthesized hemicellulosic polysaccharides, although they do not restrict the net synthesis of cell wall constituents in wheat coleoptiles. The stimulation of the synthesis of arabinoxylans and of the

  9. Treatability of cheese whey for single-cell protein production in nonsterile systems: Part II. The application of aerobic sequencing batch reactor (aerobic SBR) to produce high biomass of Dioszegia sp. TISTR 5792.

    PubMed

    Monkoondee, Sarawut; Kuntiya, Ampin; Chaiyaso, Thanongsak; Leksawasdi, Noppol; Techapun, Charin; Kawee-Ai, Arthitaya; Seesuriyachan, Phisit

    2016-07-03

    This study aimed to investigate the efficiency of an aerobic sequencing batch reactor (aerobic SBR) in a nonsterile system using the application of an experimental design via central composite design (CCD). The acidic whey obtained from lactic acid fermentation by immobilized Lactobacillus plantarum sp. TISTR 2265 was fed into the bioreactor of the aerobic SBR in an appropriate ratio between acidic whey and cheese whey to produce an acidic environment below 4.5 and then was used to support the growth of Dioszegia sp. TISTR 5792 by inhibiting bacterial contamination. At the optimal condition for a high yield of biomass production, the system was run with a hydraulic retention time (HRT) of 4 days, a solid retention time (SRT) of 8.22 days, and an acidic whey concentration of 80% feeding. The chemical oxygen demand (COD) decreased from 25,230 mg/L to 6,928 mg/L, which represented a COD removal of 72.15%. The yield of biomass production and lactose utilization by Dioszegia sp. TISTR 5792 were 13.14 g/L and 33.36%, respectively, with a long run of up to 180 cycles and the pH values of effluent were rose up to 8.32 without any pH adjustment.

  10. What Is Aerobic Dancing?

    MedlinePlus

    ... aerobics can reach up to six times the force of gravity, which is transmitted to each of the 26 bones in the foot. Because of the many side-to-side motions, shoes need an arch design that will compensate ...

  11. Analysis of thymic stromal cell subpopulations grown in vitro on extracellular matrix in defined medium. I. Growth conditions and morphology of murine thymic epithelial and mesenchymal cells.

    PubMed

    Eshel, I; Savion, N; Shoham, J

    1990-03-01

    We report here the successful selective cultivation of murine thymic mesenchymal reticular cells (MTMC) and murine thymic epithelial cells (MTEC) grown on extracellular matrix in the presence of defined medium. The selective growth of these two cell types was based on 1) conditions of tissue disruption and 2) differential growth requirements. Both cell types were dependent on transferrin, high density lipoproteins, insulin, hydrocortisone, and epidermal growth factor, whereas MTMC was dependent also on selenium and 3,5,3'-triiodothyronine. The elimination of single factors or extracellular matrix resulted in specific and different changes in the growth pattern of each cell subpopulation. Cells of both types exhibited the ultrastructural features of high metabolic activity. The epithelial nature of MTEC cultures was defined by bundles of tonofilaments and desmosomes and by positive staining to keratins and negative to vimentin. In addition MTEC were positively stained with mAb to thymic medullary epithelial cells and by Ulex europeus agglutinin, and were able to form Hassall's corpuscles, suggesting their medullary origin. MTEC were also H-2 and Ia positive. In contrast MTMC were positive for vimentin and periodic acid-Schiff, low positive for H-2, and negative for keratin and Ia. Both cells did not contain nonspecific esterase, nor did they phagocytize latex beads. With the use of all these criteria we classified MTEC as epithelial cells from the medullary compartment of the thymus and MTMC as reticular cells of mesenchymal origin.

  12. Characterization of giant spheroplasts generated from the aerobic anoxygenic photosynthetic marine bacterium Roseobacter litoralis.

    PubMed

    Nojiri, Akane; Ogita, Shinjiro; Isogai, Yasuhiro; Nishida, Hiromi

    2015-01-01

    We generated and characterized giant spheroplasts from the aerobic anoxygenic photosynthetic marine bacterium Roseobacter litoralis. The giant spheroplasts contained vacuole-like structures within the cells, mainly consisting of a single membrane. The in vivo absorption spectrum of the giant spheroplasts did not have peaks typically observed for bacteriochlorophyll a. The culture media pH decreased during the growth of the giant spheroplasts. The change in the pH profile for cells grown under light was no different from that for cells grown in the dark. These results showed that the R. litoralis giant spheroplasts formed lost their photosynthetic apparatus in culture. Most of the giant spheroplasts returned to their original size, likely via filamentous cells. The culture media pH increased during the growth of the filamentous cells. Some filamentous cells had septum-like structures. In such filamentous cells, DNA was separated. Initially, the color of the separated cells was white. Two weeks later, the cells changed to red in the dark, and the in vivo absorption spectrum of the cells had peaks typically observed for bacteriochlorophyll a. Our findings strongly suggest that the giant spheroplasts of R. litoralis can control the genetic information, return to their original cell size, and regain their original functions.

  13. Discrepancy between the short and long term effects of ouabain on the sodium pumps of human cells grown in culture.

    PubMed Central

    Griffiths, N. M.; Ogden, P. H.; Cormack, R.; Lamb, J. F.

    1991-01-01

    1. Human cells (HeLa) were cultured for periods up to 48 h in growth medium in the absence or presence of a range of concentrations of cardiac glycosides. In some experiments the potassium concentration of the medium was varied between 0.3 mM and the usual 5 mM. 2. For periods up to 2 h in ouabain the association and dissociation rate constants were measured and the equilibrium binding constant (KD) calculated; the apparent equilibrium binding constant (K'D) was measured after 1-2 days growth in ouabain. 3. Ouabain had a K'D after 2 days of 2-6 nM in 5 mM K+ growth medium, a 4 fold greater blocking effect on sodium pumps after 2 days than expected from the association and dissociation rate constants measured in untreated or previously ouabain-treated cells. 4. This effect was: (a) approximately the same over a range of external potassium concentrations from 0.3 to 5 mM, although the absolute effect of ouabain over this range of potassium was much different; (b) probably not due to different isoforms of pumps in cells grown in ouabain compared to untreated cells; (c) apparently not a consequence of internalisation of pump-glycoside complexes. 5. We conclude that ouabain has only a limited access to sodium pumps in whole cells; this could be because sodium pumps cycle continuously through an inaccessible region of the plasma membrane. This effect needs to be considered both in the assessment of the magnitude of the long term effects of cardiac glycosides on cells, and in the measurement of the glycoside affinities of various isoforms of the pump. PMID:1665734

  14. Photovoltaic characteristics of n(+)pp(+) InP solar cells grown by OMVPE

    NASA Technical Reports Server (NTRS)

    Tyagi, S.; Singh, K.; Bhimnathwala, H.; Ghandhi, S. K.; Borrego, J. M.

    1990-01-01

    The photovoltaic characteristics of n(+)/p/p(+) homojunction InP solar cells fabricated by organometallic vapor-phase epitaxy (OMVPE) are described. The cells are characterized by I-V, C-V and quantum efficiency measurements, and simulations are used to obtain various device and material parameters. The I-V characteristics show a high recombination rate in the depletion region; this is shown to be independent of the impurity used. It is shown that cadmium is easier to use as an acceptor for the p base and p(+) buffer and is therefore beneficial. The high quantum efficiency of 98 percent at long wavelengths measured in these cells indicates a very good collection efficiency in the base. The short-wavelength quantum efficiency is poor, indicating a high surface recombination.

  15. On the lattice Boltzmann method simulation of a two-phase flow bioreactor for artificially grown cartilage cells.

    PubMed

    Hussein, M A; Esterl, S; Pörtner, R; Wiegandt, K; Becker, T

    2008-12-05

    Owing to the growing demand of cartilage tissue repair and transplants, engineered cartilage cells have emerged as a prospective solution. Several bioreactors were built for artificially grown cartilage cells. In this work, a recently designed flow bed bioreactor is numerically investigated and compared with experimental results. The flow field inside the bioreactor was modelled using the lattice Boltzmann method. The flow consists of two phases which are the liquid component (nutrition supply) and gas component (oxygen supply). The flow field is simulated using the multi-phase lattice Boltzmann method, whilst the cell activity is modelled using Michaelis-Menten kinetics. The oxygen diffusion level at the exit of the nutrition phase is used as an evaluation process between the numerical and experimental results reporting the possibility of using the proposed model to fully simulate such bioreactors, though greatly saving time and money. Shear stress and pressure distributions are as well compared with published human cartilage load measurements to estimate the dynamic similarity between the bioreactor and the human knee. The predicted oxygen levels proved consistent trends with the experimental work with a 7% difference after 1h measuring time. The shear stress levels recorded 10-11 orders of magnitude lower than in humans and also one order of magnitude lower in the pressure distribution.

  16. Analysis of mesenchymal stem cells grown on a three-dimensional HYAFF 11-based prototype ligament scaffold.

    PubMed

    Cristino, S; Grassi, F; Toneguzzi, S; Piacentini, A; Grigolo, B; Santi, S; Riccio, M; Tognana, E; Facchini, A; Lisignoli, G

    2005-06-01

    Ligaments are complex structures that maintain the mechanical stability of the joint. Healing of injured ligaments involves the interactions of different cell types, local cellular environment, and the use of devices. To gain new information on the complex interactions between mesenchymal stem cells (MSCs) and a specific hyaluronan-based prototype scaffold (HYAFF, useful for ligament tissue engineering, short time-course experiments were performed to analyze the proliferation, vitality, and phenotype of MSCs grown on the scaffold. MSC proliferation was analyzed using the MTT test, during the early time points (2, 4, 6, days). Viability was assessed using calcein/acetyloxymethylester immunofluorescence dye and confocal microscopy analysis. Hyaluronic acid receptor (CD44), typical matrix ligament proteins (collagen type I, type III, laminin, fibronectin, actin), and chondrogenic/osteogenic markers (collagen type II and bone sialoprotein) were evaluated by immunohistochemistry. Our data demonstrated that MSC growth and viability were cell density-dependent. MSCs completely wrapped the fibers of the scaffold, expressed CD44, collagen type I, type III, laminin, fibronectin, and actin, and were negative to collagen type II and bone sialoprotein. These data demonstrate that MSCs survive well in the hyaluronan-based prototype ligament scaffold, as assessed after 2 days from seeding, and express CD44, a receptor important for scaffold interaction, and proteins responsible for the functional characteristics of the ligaments.

  17. Space concentrator solar cells based on multilayer LPE grown AlGaAs/GaAs heterostructure

    NASA Technical Reports Server (NTRS)

    Khvostikov, V. P.; Larionov, V. R.; Paleeva, E. V.; Sorokina, S. V.; Chosta, O. I.; Shvarts, M. Z.; Zimogorova, N. S.

    1995-01-01

    The high efficiency solar cells based on multilayer AlGaAs/GaAs heterostructures, prepared by low temperature liquid phase epitaxy (LPE), were developed and tested. An investigation of the low temperature LPE process for the crystallization of AlGaAs heterostructures of as high as 24.0 to 24.7 percent under AMO conditions at concentration ratios of 20 to 100x, were reached. Developed solar cells show substantial radiation resistance to the damage induced by 3.75 MeV electrons.

  18. High efficiency GaAs-Ge tandem solar cells grown by MOCVD

    NASA Technical Reports Server (NTRS)

    Vernon, S. M.; Tobin, S. P.; Bajgar, C.; Haven, Victor E.; Geoffroy, L. M.; Lillington, D. R.; Hart, R. E., Jr.

    1989-01-01

    High conversion efficiency and low weight are obviously desirable for solar cells intended for space applications. One promising structure is GaAs on Ge. The advantages of using Ge wafers as substrates include the following: they offer high efficiency by forming a two-junction tandem cell; low weight combined with superior strength allows usage of thin (3 mil) wafers; and they are a good substrate for GaAs, being lattice matched, thermal expansion matched, and available as large-area wafers.

  19. Human amniotic fluid cells grown in a hormone-supplemented medium: suitability for prenatal diagnosis.

    PubMed Central

    Chang, H C; Jones, O W; Masui, H

    1982-01-01

    A new supplemented medium has been developed to improve human amniotic fluid cell growth and to reduce the dependence on exogenously added serum. The medium consists of a mixture of Ham's F12 medium and Dulbecco's modified Eagle's medium supplemented with Hepes, antibiotics, and 10 growth-promoting factors at 4% fetal bovine serum. Good clonal growth is achieved consistently in 8--13 days and is associated with large numbers of metaphase cells. Primary clones may be analyzed directly, thereby reducing difficulty with interpretation of chromosomal mosaicism. This medium could also be used for cultivation of fetal solid tissues and peripheral blood cultures of lymphocytes. Images PMID:6956891

  20. Optimization towards high density quantum dots for intermediate band solar cells grown by molecular beam epitaxy

    SciTech Connect

    Zhou, D.; Sharma, G.; Fimland, B. O.; Thomassen, S. F.; Reenaas, T. W.

    2010-02-08

    We report high density quantum dots (QDs) formation with optimized growth temperature and V/III ratio. At lower growth temperature, QD density is increased, due to smaller surface migration length of In adatoms. With higher V/III, the QD density is higher but it results in large clusters formation and decreases the QD uniformity. The QD solar cell was fabricated and examined. An extended spectral response in contrast to the GaAs reference cell was presented but the external quantum efficiency at energies higher than GaAs band gap is reduced, resulting from the degradation for the emitter above the strained QD layers.

  1. Low temperature grown ZnO@TiO{sub 2} core shell nanorod arrays for dye sensitized solar cell application

    SciTech Connect

    Goh, Gregory Kia Liang; Le, Hong Quang; Huang, Tang Jiao; Hui, Benjamin Tan Tiong

    2014-06-01

    High aspect ratio ZnO nanorod arrays were synthesized on fluorine-doped tin oxide glasses via a low temperature solution method. By adjusting the growth condition and adding polyethylenimine, ZnO nanorod arrays with tunable length were successfully achieved. The ZnO@TiO{sub 2} core shells structures were realized by a fast growth method of immersion into a (NH{sub 4}){sub 2}·TiF{sub 6} solution. Transmission electron microscopy, X-ray Diffraction and energy dispersive X-ray measurements all confirmed the existence of a titania shell uniformly covering the ZnO nanorod's surface. Results of solar cell testing showed that addition of a TiO{sub 2} shell to the ZnO nanorod significantly increased short circuit current (from 4.2 to 5.2 mA/cm{sup 2}), open circuit voltage (from 0.6 V to 0.8 V) and fill factor (from 42.8% to 73.02%). The overall cell efficiency jumped from 1.1% for bare ZnO nanorod to 3.03% for a ZnO@TiO{sub 2} core shell structured solar cell with a 18–22 nm shell thickness, a nearly threefold increase. - Graphical abstract: The synthesis process of coating TiO{sub 2} shell onto ZnO nanorod core is shown schematically. A thin, uniform, and conformal shell had been grown on the surface of the ZnO core after immersing in the (NH{sub 4}){sub 2}·TiF{sub 6} solution for 5–15 min. - Highlights: • ZnO@TiO{sub 2} core shell nanorod has been grown on FTO substrate using low temperature solution method. • TEM, XRD, EDX results confirmed the existing of titana shell, uniformly covered rod's surface. • TiO{sub 2} shell suppressed recombination, demonstrated significant enhancement in cell's efficiency. • Core shell DSSC's efficiency achieved as high as 3.03%, 3 times higher than that of ZnO nanorods.

  2. Enhanced Autophagy of Adipose-Derived Stem Cells Grown on Chitosan Substrates

    PubMed Central

    Yang, Ching-Ming; Huang, Yen-Jang; Hsu, Shan-hui

    2015-01-01

    Abstract Autophagy is an important protein quality control mechanism for cells under stress conditions to promote cell survival. Modulation of autophagy on biomaterial substrates is rarely reported. In this study, the autophagy of adipose-derived stem cells (ADSCs) cultured on chitosan (CS) substrates was examined. Compared to the traditional monolayer culture, ADSCs cultured on CS substrates showed spheroid formation as well as a prolonged upregulation of autophagosomal marker-microtubule-associated protein 1 light chain 3 (LC3) II protein expression. In addition, the green fluorescent protein tagged-LC3 (GFP-LC3) expressing ADSCs also revealed more GFP-LC3 puncta on CS substrates. The enhanced autophagy on CS substrates was associated with Ca2+, while ethylene glycol tetraacetic acid (EGTA), a Ca2+ chelator, repressed the autophagy in a dose-dependent manner. Moreover, ADSC spheroids on CS substrates demonstrated a higher survival rate and autophagy response upon H2O2 treatment. The upstream components of autophagy signal pathway-UNC51-like kinase 1 (Ulk1), autophagy-related protein 13 (Atg13), and autophagy/beclin-1 regulator 1 (Ambra1) genes were more highly expressed in ADSC spheroids before and after adding H2O2 than those in the conventional culture. EGTA also decreased the cell viability and autophagy-associated gene expression for ADSC spheroids on CS substrates after H2O2 treatment. Therefore, we suggest that three-dimensional (3D) cell culture on CS may confer ADSCs the ability to increase the autophagic flux in response to stimulations in a Ca2+-dependent manner. PMID:26309785

  3. Metabolic Regulation of “Ca. Methylacidiphilum Fumariolicum” SolV Cells Grown Under Different Nitrogen and Oxygen Limitations

    PubMed Central

    Khadem, Ahmad F.; Pol, Arjan; Wieczorek, Adam S.; Jetten, Mike S. M.; Op den Camp, Huub J. M.

    2012-01-01

    Aerobic methanotrophic bacteria can use methane as their sole energy source. The discovery of “Ca. Methylacidiphilum fumariolicum” strain SolV and other verrucomicrobial methanotrophs has revealed that the ability of bacteria to oxidize CH4 is much more diverse than has previously been assumed in terms of ecology, phylogeny, and physiology. A remarkable characteristic of the methane-oxidizing Verrucomicrobia is their extremely acidophilic phenotype, growing even below pH 1. In this study we used RNA-Seq to analyze the metabolic regulation of “Ca. M. fumariolicum” SolV cells growing at μmax in batch culture or under nitrogen fixing or oxygen limited conditions in chemostats, all at pH 2. The analysis showed that two of the three pmoCAB operons each encoding particulate methane monoxygenases were differentially expressed, probably regulated by the available oxygen. The hydrogen produced during N2 fixation is apparently recycled as demonstrated by the upregulation of the genes encoding a Ni/Fe-dependent hydrogenase. These hydrogenase genes were also upregulated under low oxygen conditions. Handling of nitrosative stress was shown by the expression of the nitric oxide reductase encoding genes norB and norC under all conditions tested, the upregulation of nitrite reductase nirK under oxygen limitation and of hydroxylamine oxidoreductase hao in the presence of ammonium. Unraveling the gene regulation of carbon and nitrogen metabolism helps to understand the underlying physiological adaptations of strain SolV in view of the harsh conditions of its natural ecosystem. PMID:22848206

  4. A lentiviral sponge for miRNA-21 diminishes aerobic glycolysis in bladder cancer T24 cells via the PTEN/PI3K/AKT/mTOR axis.

    PubMed

    Yang, Xiao; Cheng, Yidong; Li, Pengchao; Tao, Jun; Deng, Xiaheng; Zhang, Xiaolei; Gu, Min; Lu, Qiang; Yin, Changjun

    2015-01-01

    Cancer cells exhibit the ability to metabolise glucose to lactate even under aerobic conditions for energy. This phenomenon is known as the Warburg effect and can be a potential target to kill cancer cells. Several studies have shown evidence for interplay between microRNAs and key metabolic enzyme effecters, which can facilitate the Warburg effect in cancer cells. In the present study, a microRNA sponge forcibly expressed using a lentiviral vector was utilised to knock down miR-21 expression in vitro. qPCR and Western blot assays were performed to evaluate the expression of a regulatory factor related to aerobic glycolysis and the signalling pathway it regulates. In bladder cancer specimens, expression levels of glycolysis-related genes [glucose transporter (GLUT)1, GLUT3, lactic dehydrogenase (LDH)A, LDHB, hexokinase (HK)1, HK2, pyruvate kinase type M (PKM) and hypoxia-inducible factor 1-alpha (HIF-1α)] were higher in tumour tissues than in adjacent tissues, suggesting the role of glycolysis in bladder cancer. miR-21 inhibition in bladder cancer cell lines resulted in reduction in tumour aerobic glycolysis. Decrease in glucose uptake and lactate production was observed upon expression of the miR-21 sponge, which promoted phosphatase and tensin homologue (PTEN) expression, decreased phosphorylated AKT and deactivated mTOR. Furthermore, messenger RNA (mRNA) and protein expression levels of glycolysis-related genes were also lower in miR-21 sponge cells compared to miR-21 control cells. Our findings suggest that miR-21 acts as a molecular switch to regulate aerobic glycolysis in bladder cancer cells via the PTEN/phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR pathway. Blocking miR-21 function can be an effective diagnostic and therapeutic approach either by itself or in combination with existing methods to treat bladder cancer.

  5. Solar Cell Efficiency and High Temperature Processing of n-type Silicon Grown by the Noncontact Crucible Method

    SciTech Connect

    Jensen, Mallory A.; LaSalvia, Vincenzo; Morishige, Ashley E.; Nakajima, Kazuo; Veschetti, Yannick; Jay, Frederic; Jouini, Anis; Youssef, Amanda; Stradins, Paul; Buonassisi, Tonio

    2016-08-01

    The capital expense (capex) of conventional crystal growth methods is a barrier to sustainable growth of the photovoltaic industry. It is challenging for innovative techniques to displace conventional growth methods due the low dislocation density and high lifetime required for high efficiency devices. One promising innovation in crystal growth is the noncontact crucible method (NOC-Si), which combines aspects of Czochralski (Cz) and conventional casting. This material has the potential to satisfy the dual requirements, with capex likely between that of Cz (high capex) and multicrystalline silicon (mc-Si, low capex). In this contribution, we observe a strong dependence of solar cell efficiency on ingot height, correlated with the evolution of swirl-like defects, for single crystalline n-type silicon grown by the NOC-Si method. We posit that these defects are similar to those observed in Cz, and we explore the response of NOC-Si to high temperature treatments including phosphorous diffusion gettering (PDG) and Tabula Rasa (TR). The highest lifetimes (2033 us for the top of the ingot and 342 us for the bottom of the ingot) are achieved for TR followed by a PDG process comprising a standard plateau and a low temperature anneal. Further improvements can be gained by tailoring the time-temperature profiles of each process. Lifetime analysis after the PDG process indicates the presence of a getterable impurity in the as-grown material, while analysis after TR points to the presence of oxide precipitates especially at the bottom of the ingot. Uniform lifetime degradation is observed after TR which we assign to a presently unknown defect. Future work includes additional TR processing to uncover the nature of this defect, microstructural characterization of suspected oxide precipitates, and optimization of the TR process to achieve the dual goals of high lifetime and spatial homogenization.

  6. Metabolism of 2-methylpropene (isobutylene) by the aerobic bacterium Mycobacterium sp. strain ELW1.

    PubMed

    Kottegoda, Samanthi; Waligora, Elizabeth; Hyman, Michael

    2015-03-01

    An aerobic bacterium (Mycobacterium sp. strain ELW1) that utilizes 2-methylpropene (isobutylene) as a sole source of carbon and energy was isolated and characterized. Strain ELW1 grew on 2-methylpropene (growth rate = 0.05 h(-1)) with a yield of 0.38 mg (dry weight) mg 2-methylpropene(-1). Strain ELW1 also grew more slowly on both cis- and trans-2-butene but did not grow on any other C2 to C5 straight-chain, branched, or chlorinated alkenes tested. Resting 2-methylpropene-grown cells consumed ethene, propene, and 1-butene without a lag phase. Epoxyethane accumulated as the only detected product of ethene oxidation. Both alkene consumption and epoxyethane production were fully inhibited in cells exposed to 1-octyne, suggesting that alkene oxidation is initiated by an alkyne-sensitive, epoxide-generating monooxygenase. Kinetic analyses indicated that 1,2-epoxy-2-methylpropane is rapidly consumed during 2-methylpropene degradation, while 2-methyl-2-propen-1-ol is not a significant metabolite of 2-methylpropene catabolism. Degradation of 1,2-epoxy-2-methylpropane by 2-methylpropene-grown cells led to the accumulation and further degradation of 2-methyl-1,2-propanediol and 2-hydroxyisobutyrate, two sequential metabolites previously identified in the aerobic microbial metabolism of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Growth of strain ELW1 on 2-methylpropene, 1,2-epoxy-2-methylpropane, 2-methyl-1,2-propanediol, and 2-hydroxyisobutyrate was fully inhibited when cobalt ions were omitted from the growth medium, while growth on 3-hydroxybutyrate and other substrates was unaffected by the absence of added cobalt ions. Our results suggest that, like aerobic MTBE- and TBA-metabolizing bacteria, strain ELW1 utilizes a cobalt/cobalamin-dependent mutase to transform 2-hydroxyisobutyrate. Our results have been interpreted in terms of their impact on our understanding of the microbial metabolism of alkenes and ether oxygenates.

  7. Metabolism of 2-Methylpropene (Isobutylene) by the Aerobic Bacterium Mycobacterium sp. Strain ELW1

    PubMed Central

    Kottegoda, Samanthi; Waligora, Elizabeth

    2015-01-01

    An aerobic bacterium (Mycobacterium sp. strain ELW1) that utilizes 2-methylpropene (isobutylene) as a sole source of carbon and energy was isolated and characterized. Strain ELW1 grew on 2-methylpropene (growth rate = 0.05 h−1) with a yield of 0.38 mg (dry weight) mg 2-methylpropene−1. Strain ELW1 also grew more slowly on both cis- and trans-2-butene but did not grow on any other C2 to C5 straight-chain, branched, or chlorinated alkenes tested. Resting 2-methylpropene-grown cells consumed ethene, propene, and 1-butene without a lag phase. Epoxyethane accumulated as the only detected product of ethene oxidation. Both alkene consumption and epoxyethane production were fully inhibited in cells exposed to 1-octyne, suggesting that alkene oxidation is initiated by an alkyne-sensitive, epoxide-generating monooxygenase. Kinetic analyses indicated that 1,2-epoxy-2-methylpropane is rapidly consumed during 2-methylpropene degradation, while 2-methyl-2-propen-1-ol is not a significant metabolite of 2-methylpropene catabolism. Degradation of 1,2-epoxy-2-methylpropane by 2-methylpropene-grown cells led to the accumulation and further degradation of 2-methyl-1,2-propanediol and 2-hydroxyisobutyrate, two sequential metabolites previously identified in the aerobic microbial metabolism of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Growth of strain ELW1 on 2-methylpropene, 1,2-epoxy-2-methylpropane, 2-methyl-1,2-propanediol, and 2-hydroxyisobutyrate was fully inhibited when cobalt ions were omitted from the growth medium, while growth on 3-hydroxybutyrate and other substrates was unaffected by the absence of added cobalt ions. Our results suggest that, like aerobic MTBE- and TBA-metabolizing bacteria, strain ELW1 utilizes a cobalt/cobalamin-dependent mutase to transform 2-hydroxyisobutyrate. Our results have been interpreted in terms of their impact on our understanding of the microbial metabolism of alkenes and ether oxygenates. PMID:25576605

  8. Highly efficient Cu(In,Ga)Se2 solar cells grown on flexible polymer films.

    PubMed

    Chirilă, Adrian; Buecheler, Stephan; Pianezzi, Fabian; Bloesch, Patrick; Gretener, Christina; Uhl, Alexander R; Fella, Carolin; Kranz, Lukas; Perrenoud, Julian; Seyrling, Sieghard; Verma, Rajneesh; Nishiwaki, Shiro; Romanyuk, Yaroslav E; Bilger, Gerhard; Tiwari, Ayodhya N

    2011-09-18

    Solar cells based on polycrystalline Cu(In,Ga)Se(2) absorber layers have yielded the highest conversion efficiency among all thin-film technologies, and the use of flexible polymer films as substrates offers several advantages in lowering manufacturing costs. However, given that conversion efficiency is crucial for cost-competitiveness, it is necessary to develop devices on flexible substrates that perform as well as those obtained on rigid substrates. Such comparable performance has not previously been achieved, primarily because polymer films require much lower substrate temperatures during absorber deposition, generally resulting in much lower efficiencies. Here we identify a strong composition gradient in the absorber layer as the main reason for inferior performance and show that, by adjusting it appropriately, very high efficiencies can be obtained. This implies that future manufacturing of highly efficient flexible solar cells could lower the cost of solar electricity and thus become a significant branch of the photovoltaic industry.

  9. Inhibition of the pentose phosphate pathway by dichloroacetate unravels a missing link between aerobic glycolysis and cancer cell proliferation.

    PubMed

    De Preter, Géraldine; Neveu, Marie-Aline; Danhier, Pierre; Brisson, Lucie; Payen, Valéry L; Porporato, Paolo E; Jordan, Bénédicte F; Sonveaux, Pierre; Gallez, Bernard

    2016-01-19

    Glucose fermentation through glycolysis even in the presence of oxygen (Warburg effect) is a common feature of cancer cells increasingly considered as an enticing target in clinical development. This study aimed to analyze the link between metabolism, energy stores and proliferation rates in cancer cells. We found that cell proliferation, evaluated by DNA synthesis quantification, is correlated to glycolytic efficiency in six cancer cell lines as well as in isogenic cancer cell lines. To further investigate the link between glycolysis and proliferation, a pharmacological inhibitor of the pentose phosphate pathway (PPP) was used. We demonstrated that reduction of PPP activity decreases cancer cells proliferation, with a profound effect in Warburg-phenotype cancer cells. The crucial role of the PPP in sustaining cancer cells proliferation was confirmed using siRNAs against glucose-6-phosphate dehydrogenase, the first and rate-limiting enzyme of the PPP. In addition, we found that dichloroacetate (DCA), a new clinically tested compound, induced a switch of glycolytic cancer cells to a more oxidative phenotype and decreased proliferation. By demonstrating that DCA decreased the activity of the PPP, we provide a new mechanism by which DCA controls cancer cells proliferation.

  10. Aerobic Reduction of Arsenate by a Bacterium Isolated From Activated Sludge

    NASA Astrophysics Data System (ADS)

    Kozai, N.; Ohnuki, T.; Hanada, S.; Nakamura, K.; Francis, A. J.

    2006-12-01

    Microlunatus phosphovorus strain NM-1 is a polyphosphate-accumulating bacterium isolated from activated sludge. This bacterium takes up a large amount of polyphosphate under aerobic conditions and release phosphate ions by hydrolysis of polyphosphate to orthophosphate under anaerobic conditions to derive energy for taking up substrates. To understand the nature of this strain, especially, influence of potential contaminants in sewage and wastewater on growth, we have been investigating behavior of this bacterium in media containing arsenic. The present paper mainly reports reduction of arsenate by this bacterium under aerobic conditions. The strain NM-1 (JCM 9379) was aerobically cultured at 30 °C in a nutrient medium containing 2.5 g/l peptone, 0.5 g/l glucose, 1.5 g/l yeast extract, and arsenic [Na2HAsO4 (As(V)) or Na3AsO3 (As(III))] at concentrations between 0 and 50 mM. The cells collected from arsenic-free media were dispersed in buffer solutions containing 2mM HEPES, 10mM NaCl, prescribed concentrations of As(V), and 0-0.2 percent glucose. Then, this cell suspension was kept at 20 °C under aerobic or anaerobic conditions. The speciation of arsenic was carried out by ion chromatography and ICP-MS. The growth of the strain under aerobic conditions was enhanced by the addition of As(V) at the concentration between 1 and 10 mM. The maximum optical density of the culture in the medium containing 5mM As(V) was 1.4 times greater than that of the control culture. Below the As(V) concentration of 10mM, most of the As(V) was reduced to As(III). The growth of the strain under anaerobic conditions has not been observed so far. The cells in the buffer solutions reduced As(V) under aerobic condition. The reduction was enhanced by the addition of glucose. However, the cell did not reduce As(V) under anaerobic conditions. The strain NM-1 showed high resistance to As(V) and As(III). The maximum optical density of the culture grown in a medium containing 50 mM As(V) was only

  11. Production of somatic cell nuclear transfer embryos using in vitro-grown and in vitro-matured oocytes in rabbits.

    PubMed

    Sugimoto, Hironobu; Kida, Yuta; Oh, Noriyoshi; Kitada, Kensaku; Matsumoto, Kazuya; Saeki, Kazuhiro; Taniguchi, Takeshi; Hosoi, Yoshihiko

    2015-08-01

    We examined growing oocytes collected from follicles remaining in superovulated rabbit ovaries, that were grown (in vitro growth, IVG) and matured (in vitro maturation, IVM) in vitro. We produced somatic cell nuclear transfer (SCNT) embryos using the mature oocytes and examined whether these embryos have the ability to develop to the blastocyst stage. In addition, we examined the effects of trichostatin A (TSA), a histone deacetylase inhibitor (HDACi), on the developmental competence of SCNT embryos derived from IVG-IVM oocytes. After growth for 7 days and maturation for 14-16 h in vitro, the growing oocytes reached the metaphase II stage (51.4%). After SCNT, these reconstructed embryos reached the blastocyst stage (20%). Furthermore, the rate of development to the blastocyst stage and the number of cells in the blastocysts in SCNT embryos derived from IVG-IVM oocytes were significantly higher for TSA-treated embryos compared with TSA-untreated embryos (40.6 versus 21.4% and 353.1 ± 59.1 versus 202.5 ± 54.6, P < 0.05). These results indicate that rabbit SCNT embryos using IVG-IVM oocytes have the developmental competence to reach the blastocyst stage.

  12. Hybrid solar cells based on dc magnetron sputtered films of n-ITO on APMOVPE grown p-InP

    NASA Technical Reports Server (NTRS)

    Coutts, T. J.; Li, X.; Wanlass, M. W.; Emery, K. A.; Gessert, T. A.

    1988-01-01

    Hybrid indium-tin-oxide (ITO)/InP solar cells are discussed. The cells are constructed by dc magnetron sputter deposition of ITO onto high-quality InP films grown by atmospheric pressure metal-organic vapor-phase epitaxy (APMOVPE). A record efficiency of 18.9 percent, measured under standard Solar Energy Research Institute reporting conditions, has been obtained. The p-InP surface is shown to be type converted, principally by the ITO, but with the extent of conversion being modified by the nature of the sputtering gas. The deposition process, in itself, is not responsible for the type conversion. Dark currents have been suppressed by more than three orders of magnitude by the addition of hydrogen to the sputtering gas during deposition of a thin (5 nm) interface layer. Without this layer, and using only the more usual argon/oxygen mixture, the devices had poorer efficiencies and were unstable. A discussion of associated quantum efficiencies and capacitance/voltage measurements is also presented from which it is concluded that further improvements in efficiency will result from better control over the type-conversion process.

  13. Genetic stability and mutant selection in Sabin 2 strain of oral poliovirus vaccine grown under different cell culture conditions.

    PubMed

    Taffs, R E; Chumakov, K M; Rezapkin, G V; Lu, Z; Douthitt, M; Dragunsky, E M; Levenbook, I S

    1995-06-01

    Mutations that consistently accumulated in the attenuated Sabin 2 strain of poliovirus during propagation in cell cultures were identified by sequence heterogeneity assay and quantified by mutant analysis by PCR and restriction enzyme cleavage (MAPREC). Eight additional sites previously identified in stool isolates were also examined by MAPREC in the virus passages. The pattern of selectable mutations and the rate of their accumulation depended on the type and confluence of the cell culture and the temperature of virus growth. Five unstable genomic sites were identified in Sabin 2 virus passaged 10 times at 34 degrees in African green monkey kidney (AGMK) cells, with the mutations accumulating in the range 1 to 24%. Accumulation of these mutations did not appear to result in a loss of attenuated phenotype since the virus passaged under these conditions passed the monkey neurovirulence test (MNVT). The content of the 481-G revertant known to be related to neurovirulence in monkeys did not increase. Thus, our results suggest that upon growth of Sabin 2 virus in AGMK cells at 34 degrees, the key determinant(s) of attenuation remained stable, and the mutations that occurred did not affect monkey neurovirulence. In virus passaged 10 times at 37 degrees in AGMK cells, 4 unstable genomic sites were identified, in some of them accumulating up to 12% of the mutants. This virus sample severely failed the MNVT. Virus passaged in Vero cells at 34 and 37 degrees accumulated mutants at 7 and 14 genomic sites, respectively, including 481-G in both cases, with almost complete substitution of the original nucleotides at some of the sites. We tested 44 commercial monopools of Type 2 OPV and found out that all of them contained 481-G revertants in the range 0.4-1.1%. An increase in the 481-G revertants in passaged viruses to the level of 4% and above correlated with failure of these samples by the MNVT. Since the pattern of selectable mutations differed in viruses grown in the two

  14. Effect of chlorate, molybdate, and shikimic acid on Salmonella enterica serovar Typhimurium in aerobic and anaerobic cultures.

    PubMed

    Oliver, Christy E; Beier, Ross C; Hume, Michael E; Horrocks, Shane M; Casey, Thomas A; Caton, Joel S; Nisbet, David J; Smith, David J; Krueger, Nathan A; Anderson, Robin C

    2010-04-01

    Experiments were conducted to determine factors that affect sensitivity of Salmonella enterica serovar Typhimurium to sodium chlorate (5mM). In our first experiment, cultures grown without chlorate grew more rapidly than those with chlorate. An extended lag before logarithmic growth was observed in anaerobic but not aerobic cultures containing chlorate. Chlorate inhibition of growth during aerobic culture began later than that observed in anaerobic cultures but persisted once inhibition was apparent. Conversely, anaerobic cultures appeared to adapt to chlorate after approximately 10h of incubation, exhibiting rapid compensatory growth. In anaerobic chlorate-containing cultures, 20% of total viable counts were resistant to chlorate by 6h and had propagated to 100% resistance (>10(9)CFU mL(-1)) by 24h. In the aerobic chlorate-containing cultures, 12.9% of colonies had detectable resistance to chlorate by 6h, but only 1% retained detectable resistance at 24h, likely because these cultures had opportunity to respire on oxygen and were thus not enriched via the selective pressure of chlorate. In another study, treatment with shikimic acid (0.34 mM), molybdate (1mM) or their combination had little effect on aerobic or anaerobic growth of Salmonella in the absence of added chlorate. As observed in our earlier study, chlorate resistance was not detected in any cultures without added chlorate. Chlorate resistant Salmonella were recovered at equivalent numbers regardless of treatment after 8h of aerobic or anaerobic culture with added chlorate; however, by 24h incubation chlorate sensitivity was completely restored to aerobic but not anaerobic cultures treated with shikimic acid or molybdate but not their combination. Results indicate that anaerobic adaptation of S. Typhimurium to sodium chlorate during pure culture is likely due to the selective propagation of low numbers of cells exhibiting spontaneous resistance to chlorate and this resistance is not reversible by

  15. Performance of microbial electrolysis cells with bioanodes grown at different external resistances.

    PubMed

    Rago, Laura; Monpart, Nuria; Cortés, Pilar; Baeza, Juan A; Guisasola, Albert

    2016-01-01

    Bioelectrochemical systems need an anode with a high abundance of exoelectrogenic bacteria for an optimal performance. Among all possible operational parameters for an efficient enrichment, the role of external resistance in microbial fuel cell (MFC) has gained a lot of interest since it indirectly poises an anode potential, a key parameter for biofilm distribution and morphology. Thus, this work aims at investigating and discussing whether bioanodes selected at different external resistances under MFC operation present different responses under both MFC and microbial electrolysis cell (MEC) operation. A better MEC performance (i.e. shorter start-up time, higher current intensity and higher H2 production rate) was obtained with an anode from an MFC developed under low external resistance. Quantitative real-time polymerase chain reaction (qPCR) confirmed that a low external resistance provides an MFC anodic biofilm with the highest content of Geobacter because it allows higher current intensity, which is correlated to exoelectrogenic activity. High external resistances such as 1,000 Ω led to a slower start-up time under MEC operation.

  16. Stable release of BDNF from the fibroblast cell line NIH3T3 grown on silicone elastomers enhances survival of spiral ganglion cells in vitro and in vivo.

    PubMed

    Warnecke, Athanasia; Sasse, Susanne; Wenzel, Gentiana I; Hoffmann, Andrea; Gross, Gerhard; Paasche, Gerrit; Scheper, Verena; Reich, Uta; Esser, Karl-Heinz; Lenarz, Thomas; Stöver, Timo; Wissel, Kirsten

    2012-07-01

    The treatment of choice for profound sensorineural hearing loss (SNHL) is direct electrical stimulation of spiral ganglion cells (SGC) via a cochlear implant (CI). The number and excitability of SGC seem to be critical for the success that can be achieved via CI treatment. However, SNHL is associated with degeneration of SGC. Long-term drug delivery to the inner ear for improving SGC survival may be achieved by functionalisation of CI electrodes with cells providing growth factors. Therefore, the capacity of brain-derived neurotrophic factor (BDNF)-secreting NIH3T3 cells grown on cylindrically shaped silicone elastomers (SE) to exert local and sustained neuroprotective effects was assessed in vitro and in vivo. An in vitro model to investigate adhesion and cell growth of lentivirally modified NIH3T3 cells synthesising BDNF on SE was established. The bioactivity of BDNF was characterised by co-cultivation of SGC with cell-coated SE. In addition, cell-coated SE were implanted into deafened guinea pigs. The recombinant NIH3T3 cells proliferated on silicone surfaces during 14 days of cultivation and expressed significantly increasing BDNF levels. Enhanced survival rates and neurite outgrowth of SGC demonstrated the bioactivity of BDNF in vitro. Implantation of SE with adhering BDNF-secreting NIH3T3 cells into the cochleae of systemically deafened guinea pigs induced a significant increase in SGC survival in comparison to SE without cell coating. Our data demonstrate a novel approach of cell-based long-term drug delivery to support SGC survival in vitro and in vivo. This therapeutic strategy--once transferred to cells suitable for clinical application--may improve CI performance.

  17. Dye-sensitized solar cell employing zinc oxide aggregates grown in the presence of lithium

    DOEpatents

    Zhang, Qifeng; Cao, Guozhong

    2013-10-15

    Provided are a novel ZnO dye-sensitized solar cell and method of fabricating the same. In one embodiment, deliberately added lithium ions are used to mediate the growth of ZnO aggregates. The use of lithium provides ZnO aggregates that have advantageous microstructure, morphology, crystallinity, and operational characteristics. Employing lithium during aggregate synthesis results in a polydisperse collection of ZnO aggregates favorable for porosity and light scattering. The resulting nanocrystallites forming the aggregates have improved crystallinity and more favorable facets for dye molecule absorption. The lithium synthesis improves the surface stability of ZnO in acidic dyes. The procedures developed and disclosed herein also help ensure the formation of an aggregate film that has a high homogeneity of thickness, a high packing density, a high specific surface area, and good electrical contact between the film and the fluorine-doped tin oxide electrode and among the aggregate particles.

  18. Genotoxic Effects of Low- and High-LET Radiation on Human Epithelial Cells Grown in 2-D Versus 3-D Culture

    NASA Technical Reports Server (NTRS)

    Patel, Z. S.; Cucinotta, F. A.; Huff, J. L.

    2011-01-01

    Risk estimation for radiation-induced cancer relies heavily on human epidemiology data obtained from terrestrial irradiation incidents from sources such as medical and occupational exposures as well as from the atomic bomb survivors. No such data exists for exposures to the types and doses of high-LET radiation that will be encountered during space travel; therefore, risk assessment for space radiation requires the use of data derived from cell culture and animal models. The use of experimental models that most accurately replicate the response of human tissues is critical for precision in risk projections. This work compares the genotoxic effects of radiation on normal human epithelial cells grown in standard 2-D monolayer culture compared to 3-D organotypic co-culture conditions. These 3-D organotypic models mimic the morphological features, differentiation markers, and growth characteristics of fully-differentiated normal human tissue and are reproducible using defined components. Cultures were irradiated with 2 Gy low-LET gamma rays or varying doses of high-LET particle radiation and genotoxic damage was measured using a modified cytokinesis block micronucleus assay. Our results revealed a 2-fold increase in residual damage in 2 Gy gamma irradiated cells grown under organotypic culture conditions compared to monolayer culture. Irradiation with high-LET particle radiation gave similar results, while background levels of damage were comparable under both scenarios. These observations may be related to the phenomenon of "multicellular resistance" where cancer cells grown as 3-D spheroids or in vivo exhibit an increased resistance to killing by chemotherapeutic agents compared to the same cells grown in 2-D culture. A variety of factors are likely involved in mediating this process, including increased cell-cell communication, microenvironment influences, and changes in cell cycle kinetics that may promote survival of damaged cells in 3-D culture that would

  19. NADPH:cytochrome c (P450) reductase activates tirapazamine (SR4233) to restore hypoxic and oxic cytotoxicity in an aerobic resistant derivative of the A549 lung cancer cell line

    PubMed Central

    Saunders, M P; Patterson, A V; Chinje, E C; Harris, A L; Stratford, I J

    2000-01-01

    Tirapazamine (TPZ, SR4233, WIN 59075) is a bioreductive drug that is activated in regions of low oxygen tension to a cytotoxic radical intermediate. This labile metabolite shows high selective toxicity towards hypoxic cells, such as those found in solid tumours. Under aerobic conditions, redox cycling occurs with subsequent generation of superoxide radicals, which are also cytotoxic. NADPH:cytochrome c (P450) reductase (P450R) is a one-electron reducing enzyme that efficiently activates TPZ. Recently a derivative of the A549 non-small cell lung cancer cell line (A549c50) was generated that showed substantially reduced P450R activity compared to its parental line (Elwell et al (1997) Biochem Pharmacol54: 249–257). Here, it is demonstrated that the A549c50 cells are markedly more resistant to TPZ under both aerobic and hypoxic conditions. In addition, these cells have a dramatically impaired ability to metabolize TPZ to its two-electron reduction product, SR4317, under hypoxic conditions when compared to wild-type cells. P450R activity in the A549c50 cells was reintroduced to similar levels as that seen in the parental A549 cells by transfection of the full-length cDNA for human P450R. These P450R over-expressing cells exhibit restored sensitivity to TPZ under both aerobic and hypoxic conditions, comparable to that found in the original parental A549 cells. Further, the ability of the transfected cells to metabolize TPZ to SR4317 under hypoxic conditions is also shown to be restored. This provides further evidence that P450R can play an important role in the activation, metabolism and toxicity of this lead bioreductive drug. © 2000 Cancer Research Campaign PMID:10682679

  20. Dilute Nitride GaNP Wide Bandgap Solar Cells Grown by Gas-Source Molecular Beam Epitaxy

    NASA Astrophysics Data System (ADS)

    Sukrittanon, Supanee

    Integration of III-V semiconductors and Si is a very attractive means to achieve low-cost high-efficiency solar cells. A promising configuration is to utilize a dual-junction solar cell, in which Si is employed as the bottom junction and a wide-bandgap III-V semiconductor as the top junction. The use of a III-V semiconductor as a top junction offers the potential to achieve higher efficiencies than today's best Si solar cell. Dilute nitride GaNP is a promising candidate for the top cell in dual-junction solar cells because it possesses several extremely important attributes: a direct-bandgap that is also tunable as well as easily-attained lattice-match with Si. As a first step towards integration of GaNP solar cells onto Si, the goal of this dissertation is to optimize and demonstrate GaNP solar cells grown by gas-source molecular beam epitaxy (GSMBE) on GaP (001) substrate. The dissertation is divided into three major parts. In the first part, we demonstrate ˜ 2.05 eV ([N]˜ 1.8%) dilute nitride GaNP thin film solar cells, in which the GaNP is closely lattice-matched to Si, on GaP substrates. From transmission electron microscopy (TEM), the device exhibits defects only at the GaNP/GaP interface, and no threading dislocations in an active layer are observed. Our best GaNP solar cell achieved an efficiency of 7.9% with anti-reflection (AR) coating and no window layer. This GaNP solar cell's efficiency is higher than the most efficient GaP solar cell to date and higher than other solar cells with similar direct bandgap (InGaP, GaAsP). Through a systematic study of the structural, electrical, and optical properties of the device, efficient broadband optical absorption and enhanced solar cell performance using GaNP are demonstrated. In the second part, we demonstrate the successful fabrication of GaP/GaNP core/shell microwires utilizing a novel technique: top-down reactive-ion etching (RIE) to create the cores and MBE to create the shells. Systematic studies have been

  1. The effect of adriamycin and 4'-deoxydoxorubicin on cell survival of human lung tumour cells grown in monolayer and as spheroids.

    PubMed Central

    Kerr, D. J.; Wheldon, T. E.; Kerr, A. M.; Freshney, R. I.; Kaye, S. B.

    1986-01-01

    Using growth delay and clonogenic cell survival as end points, we have shown that the 3-dimensional structure of human lung tumour spheroids confers a degree of resistance to the anthracyclines adriamycin and 4'-deoxydoxorubicin, relative to cells grown as monolayer. 4'-deoxydoxorubicin induces a longer growth delay and greater clonogenic cell kill than adriamycin in spheroids, although it is no more cytotoxic in monolayer (exponential and plateau phase). There is a log linear relationship between clonogenic cell survival and duration of adriamycin exposure in monolayers, and biphasic curve with a lesser degree of cell kill for disaggregated spheroid cells. Using fluorescent microscopy we have demonstrated, qualitatively, that the more lipophilic analogue partitions into the spheroid more rapidly and to a greater degree than adriamycin. It is possible that adriamycin penetration is a relatively important aspect of spheroid drug resistance, which may be related to intraspheroidal pH gradients, and that we have partially overcome this by using a lipophilic analogue. Images Figure 7 PMID:3756078

  2. Hydrogen evolution by strictly aerobic hydrogen bacteria under anaerobic conditions.

    PubMed

    Kuhn, M; Steinbüchel, A; Schlegel, H G

    1984-08-01

    When strains and mutants of the strictly aerobic hydrogen-oxidizing bacterium Alcaligenes eutrophus are grown heterotrophically on gluconate or fructose and are subsequently exposed to anaerobic conditions in the presence of the organic substrates, molecular hydrogen is evolved. Hydrogen evolution started immediately after the suspension was flushed with nitrogen, reached maximum rates of 70 to 100 mumol of H2 per h per g of protein, and continued with slowly decreasing rates for at least 18 h. The addition of oxygen to an H2-evolving culture, as well as the addition of nitrate to cells (which had formed the dissimilatory nitrate reductase system during the preceding growth), caused immediate cessation of hydrogen evolution. Formate is not the source of H2 evolution. The rates of H2 evolution with formate as the substrate were lower than those with gluconate. The formate hydrogenlyase system was not detectable in intact cells or crude cell extracts. Rather the cytoplasmic, NAD-reducing hydrogenase is involved by catalyzing the release of excessive reducing equivalents under anaerobic conditions in the absence of suitable electron acceptors. This conclusion is based on the following experimental results. H2 is formed only by cells which had synthesized the hydrogenases during growth. Mutants lacking the membrane-bound hydrogenase were still able to evolve H2. Mutants lacking the NAD-reducing or both hydrogenases were unable to evolve H2.

  3. The Treatment of PPCP-Containing Sewage in an Anoxic/Aerobic Reactor Coupled with a Novel Design of Solid Plain Graphite-Plates Microbial Fuel Cell

    PubMed Central

    Chang, Yi-Tang; Yang, Chu-Wen; Chang, Yu-Jie; Chang, Ting-Chieh; Wei, Da-Jiun

    2014-01-01

    Synthetic sewage containing high concentrations of pharmaceuticals and personal care products (PPCPs, mg/L level) was treated using an anoxic/aerobic (A/O) reactor coupled with a microbial fuel cell (MFC) at hydraulic retention time (HRT) of 8 h. A novel design of solid plain graphite plates (SPGRPs) was used for the high surface area biodegradation of the PPCP-containing sewage and for the generation of electricity. The average CODCr and total nitrogen removal efficiencies achieved were 97.20% and 83.75%, respectively. High removal efficiencies of pharmaceuticals, including acetaminophen, ibuprofen, and sulfamethoxazole, were also obtained and ranged from 98.21% to 99.89%. A maximum power density of 532.61 mW/cm2 and a maximum coulombic efficiency of 25.20% were measured for the SPGRP MFC at the anode. Distinct differences in the bacterial community were presented at various locations including the mixed liquor suspended solids and biofilms. The bacterial groups involved in PPCP biodegradation were identified as Dechloromonas spp., Sphingomonas sp., and Pseudomonas aeruginosa. This design, which couples an A/O reactor with a novel design of SPGRP MFC, allows the simultaneous removal of PPCPs and successful electricity production. PMID:25197659

  4. The treatment of PPCP-containing sewage in an anoxic/aerobic reactor coupled with a novel design of solid plain graphite-plates microbial fuel cell.

    PubMed

    Chang, Yi-Tang; Yang, Chu-Wen; Chang, Yu-Jie; Chang, Ting-Chieh; Wei, Da-Jiun

    2014-01-01

    Synthetic sewage containing high concentrations of pharmaceuticals and personal care products (PPCPs, mg/L level) was treated using an anoxic/aerobic (A/O) reactor coupled with a microbial fuel cell (MFC) at hydraulic retention time (HRT) of 8 h. A novel design of solid plain graphite plates (SPGRPs) was used for the high surface area biodegradation of the PPCP-containing sewage and for the generation of electricity. The average CODCr and total nitrogen removal efficiencies achieved were 97.20% and 83.75%, respectively. High removal efficiencies of pharmaceuticals, including acetaminophen, ibuprofen, and sulfamethoxazole, were also obtained and ranged from 98.21% to 99.89%. A maximum power density of 532.61 mW/cm(2) and a maximum coulombic efficiency of 25.20% were measured for the SPGRP MFC at the anode. Distinct differences in the bacterial community were presented at various locations including the mixed liquor suspended solids and biofilms. The bacterial groups involved in PPCP biodegradation were identified as Dechloromonas spp., Sphingomonas sp., and Pseudomonas aeruginosa. This design, which couples an A/O reactor with a novel design of SPGRP MFC, allows the simultaneous removal of PPCPs and successful electricity production.

  5. Analysis of the 5'UTR of HCV genotype 3 grown in vitro in human B cells, T cells, and macrophages

    PubMed Central

    2010-01-01

    Background Previously, we have reported the isolation and molecular characterization of human Hepatitis C virus genotype 1 (HCV-1) from infected patients. We are now reporting an analysis of HCV obtained from patients infected with HCV genotype 3 (HCV-3) as diagnosed by clinical laboratories. Results HCV was cultured in vitro using our system. HCV RNA was isolated from patients' blood and from HCV cultured in various cell types for up to three months. The 5'UTR of these isolates were used for comparisons. Results revealed a number of sequence changes as compared to the serum RNA. The HCV RNA produced efficiently by infected macrophages, B-cells, and T-cells had sequences similar to HCV-1, which suggests that selection of the variants was performed at the level of macrophages. Virus with sequences similar to HCV-1 replicated better in macrophages than HCV having a 5'UTR similar to HCV-3. Conclusions Although HCV-3 replicates in cell types such as B-cells, T-cells, and macrophages, it may require a different primary cell type for the same purpose. Therefore, in our opinion, HCV-3 does not replicate efficiently in macrophages, and patients infected with HCV-3 may contain a population of HCV-1 in their blood. PMID:20626910

  6. Sub-toxic concentrations of volatile organic compounds inhibit extracellular respiration of Escherichia coli cells grown in anodic bioelectrochemical systems.

    PubMed

    Santoro, Carlo; Mohidin, Abeed Fatima; Grasso, Letizia Lo; Seviour, Thomas; Palanisamy, Kannan; Hinks, Jamie; Lauro, Federico M; Marsili, Enrico

    2016-12-01

    Low-cost and rapid detection of volatile organic compounds (VOCs) is important for the control of water quality of used water and protection of downstream used water treatment processes. In this work, the effect of sub-toxic concentration of VOCs on the current output of Escherichia coli in bioelectrochemical systems (BES) is shown, in light of environmental sensing applications for sewage and used water networks. E. coli cells were grown on carbon felt electrodes in artificial used water, to increase sensitivity and decrease response time for detection. Extracellular electron transfer was promoted by the addition of a biocompatible redox mediator, 2-hydroxy-1,4-naphthoquinone (HNQ). Among the eight VOCs investigated, toluene is the most toxic to E. coli, with a detection limit of 50±2mgL(-1) and current output of 32±1nAmg(-1)L(-1). This work offers a straightforward route to enhance the detection of organic contaminants in used water for environmental applications.

  7. Dance--Aerobic and Anaerobic.

    ERIC Educational Resources Information Center

    Cohen, Arlette

    1984-01-01

    This article defines and explains aerobic exercise and its effects on the cardiovascular system. Various studies on dancers are cited indicating that dance is an anaerobic activity with some small degree of aerobic benefit. (DF)

  8. Genetic processes in intergeneric cell hybrids Atropa + Nicotiana : 1. Genetic constitution of cells of different clonal origin grown in vitro.

    PubMed

    Gleba, Y Y; Momot, V P; Okolot, A N; Cherep, N N; Skarzhynskaya, M V; Kotov, V

    1983-06-01

    The genetic constitution of the cell hybrids Atropa belladonna + Nicotiana chinensis, obtained by cloning of individual heteroplasmic protoplast fusion products (Gleba et al. 1982) and cultured in vitro for 12 months, has been studied. The study comprised 11 hybrid cell clones of independent origin and included analysis of a) chromosome number, size, morphology, and relative position in metaphase plates, b) multiple molecular forms of the enzymes esterase and amylase, and c) relative nuclear DNA content. The data obtained permit us to conclude that, after one year of unorganized growth in vitro, the cells of most (8) clones had retained chromosomes of both parents, while species-specific elimination of nearly all Atropa chromosomes had occurred in three clones. About half of the non-segregating clones possess 120-150 chromosomes including 50-70 of Atropa and 50-90 of Nicotiana. Other clones are polyploid and possess 200-250 chromosomes with a predominance of either Atropa or Nicotiana chromosome types. Only a few chromosomal changes (reconstituted chromosomes, ring chromosomes) have been detected. In some metaphase plates, chromosomes of the two parents tend to group separately, indicating non-random arrangement of chromosomes of the two parents within the hybrid nucleus. Cytophotometric studies of the relative nuclear DNA content showed that distribution histograms for cell clones were similar to those of non-hybrid cultured cells. Cell populations were relatively homogenous and do not indicate any genetic instability as a result of hybridization between remote plant species. Biochemical analysis of isoenzyme patterns confirmed that in most cell clones, species-specific multiple molecular forms of esterase and amylase from both parents were present, i.e. genetic material of both parental species was expressed in the cell hybrids.

  9. DNA damage in the gill cells of the marine scallop Mizuhopecten yessoensis during anoxic stress and aerobic recovery

    NASA Astrophysics Data System (ADS)

    Slobodskova, Valentina V.; Zhukovskaya, Avianna F.; Chelomin, Victor P.

    2012-06-01

    Anoxia-induced DNA damage in the gill cells of the marine scallop Mizuhopecten yessoensis was assessed with the alkaline comet assay (single-cell gel electrophoresis). The alkaline comet assay method for detecting DNA strand breaks and alkali labile sites in individual cells. DNA damage was determened in the scallops ( M. yessoensis) gill cells. The scallops were exposed to air for 8 h showing a clear increase in the levels of DNA damage. After the air exposure, M. yessoensis were re-submersed for a period of 12 h, leading values to return to a pre-aerial exposure level. Control animals were kept immersed during the whole period. The resulting data demonstrate that natural influences, such as oxygen depletion (anoxia) in seawater, can be responsible for the induction of DNA damage. If the scallops were re-immersed in oxic conditions, the anoxically induced breaks were repaired. The main mechanisms influencing the integrity of the DNA structure are discussed in this paper.

  10. Anhydrobiosis in yeast: FT-IR spectroscopic studies of yeast grown under conditions of severe oxygen limitation.

    PubMed

    Grube, Mara; Gavare, Marita; Rozenfelde, Linda; Rapoport, Alexander

    2014-01-01

    Anhydrobiosis is a unique state of living organisms when metabolism is temporarily and reversibly delayed in response to the extreme desiccation of cells. The production of dry active preparations of yeast grown under anaerobic conditions is not currently possible because preparations are extremely sensitive to the dehydration procedure, though they could be very helpful in different biotechnological processes, including bioethanol production. To characterize mechanisms responsible for such sensitivity to the dehydration procedure, Fourier transform infrared spectroscopy was used to study the composition of aerobically grown yeast Saccharomyces cerevisiae resistant to dehydration and grown under conditions of severe oxygen limitation and sensitive to dehydration. Results indicated that significantly lower amounts of lipids in cells, grown under conditions of severe oxygen limitation, may be related to the mechanisms of sensitivity. Dehydration of both resistant and sensitive S. cerevisiae cells was accompanied by similar changes in main cellular compounds. Amounts of nucleic acids and proteins decreased slightly, whereas that of lipids and carbohydrates increased. Artificially reduced sensitivity to dehydration in S. cerevisiae cells, grown under conditions of severe oxygen limitation, led to the increase in the lipid concentration. The chemical composition of S. cerevisiae membranes is proposed to dictate the resistance to dehydration in resistant and sensitive cells.

  11. Hydrogen Photoproduction by Nutrient-Deprived Chalamydomonas reinhardtii Cells Immobilized Within Thin Alginate Films Under Aerobic and Anaerobic Conditions

    SciTech Connect

    Kosourov, S. N.; Seibert, M.

    2009-01-01

    A new technique for immobilizing H{sub 2}-photoproducing green algae within a thin (<400 {micro}m) alginate film has been developed. Alginate films with entrapped sulfur/phosphorus-deprived Chlamydomonas reinhardtii, strain cc124, cells demonstrate (a) higher cell density (up to 2,000 {micro}g Chl mL{sup -1} of matrix), (b) kinetics of H{sub 2} photoproduction similar to sulfur-deprived suspension cultures, (c) higher specific rates (up to 12.5 {micro}mol mg{sup -1} Chl h{sup -1}) of H{sub 2} evolution, (d) light conversion efficiencies to H{sub 2} of over 1% and (e) unexpectedly high resistance of the H{sub 2}-photoproducing system to inactivation by atmospheric O{sub 2}. The algal cells, entrapped in alginate and then placed in vials containing 21% O{sub 2} in the headspace, evolved up to 67% of the H{sub 2} gas produced under anaerobic conditions. The results indicate that the lower susceptibility of the immobilized algal H{sub 2}-producing system to inactivation by O{sub 2} depends on two factors: (a) the presence of acetate in the medium, which supports higher rates of respiration and (b) the capability of the alginate polymer itself to effectively separate the entrapped cells from O{sub 2} in the liquid and headspace and restrict O{sub 2} diffusion into the matrix. The strategy presented for immobilizing algal cells within thin polymeric matrices shows the potential for scale-up and possible future applications.

  12. Progress in the Efficiency of Wide-Gap Cu(In1-xGax)Se2 Solar Cells Using CIGSe Layers Grown in Water Vapor

    NASA Astrophysics Data System (ADS)

    Ishizuka, Shogo; Sakurai, Keiichiro; Yamada, Akimasa; Shibata, Hajime; Matsubara, Koji; Yonemura, Minoru; Nakamura, Satoshi; Nakanishi, Hisayuki; Kojima, Takeshi; Niki, Shigeru

    2005-05-01

    Progress in the performance of wide-gap Cu(In1-xGax)Se2 (CIGSe) solar cells for x values around 0.5 has been demonstrated using CIGSe layers grown in the presence of water vapor. While CIGSe thin films deposited in the presence of water vapor showed variations in electrical properties such as increases in hole carrier density and a consequent enhancement of p-type conductivity, no significant changes in the morphology and growth orientation were observed. Both the open circuit voltages and current densities of the CIGSe solar cells were improved using CIGSe layers grown in water vapor. An 18.1%-efficient cell with an open circuit voltage of 0.744 V, a current density of 32.4 mA/cm2 and a fill factor of 0.752 was fabricated from a 1.3 eV-CIGSe (x ˜ 0.48) layer.

  13. Implementation of Aerobic Programs.

    ERIC Educational Resources Information Center

    American Alliance for Health, Physical Education, Recreation and Dance (AAHPERD).

    This information is intended for health professionals interested in implementing aerobic exercise programs in public schools, institutions of higher learning, and business and industry workplaces. The papers are divided into three general sections. The introductory section presents a basis for adhering to a health fitness lifestyle, using…

  14. Aerobic Dance in Public Schools.

    ERIC Educational Resources Information Center

    Chiles, Barbara Ann; Moore, Suzanne

    1981-01-01

    Aerobic dance offers a challenging workout in a social atmosphere. Though some physical education instructors tend to exclude dance units from the curriculum, most could teach aerobic dance if they had a basic knowledge of aerobic routines. The outline for a unit to be used in the class is presented. (JN)

  15. Multilayer-Grown Ultrathin Nanostructured GaAs Solar Cells as a Cost-Competitive Materials Platform for III-V Photovoltaics.

    PubMed

    Gai, Boju; Sun, Yukun; Lim, Haneol; Chen, Huandong; Faucher, Joseph; Lee, Minjoo L; Yoon, Jongseung

    2017-01-24

    Large-scale deployment of GaAs solar cells in terrestrial photovoltaics demands significant cost reduction for preparing device-quality epitaxial materials. Although multilayer epitaxial growth in conjunction with printing-based materials assemblies has been proposed as a promising route to achieve this goal, their practical implementation remains challenging owing to the degradation of materials properties and resulting nonuniform device performance between solar cells grown in different sequences. Here we report an alternative approach to circumvent these limitations and enable multilayer-grown GaAs solar cells with uniform photovoltaic performance. Ultrathin single-junction GaAs solar cells having a 300-nm-thick absorber (i.e., emitter and base) are epitaxially grown in triple-stack releasable multilayer assemblies by molecular beam epitaxy using beryllium as a p-type impurity. Microscale (∼500 × 500 μm(2)) GaAs solar cells fabricated from respective device layers exhibit excellent uniformity (<3% relative) of photovoltaic performance and contact properties owing to the suppressed diffusion of p-type dopant as well as substantially reduced time of epitaxial growth associated with ultrathin device configuration. Bifacial photon management employing hexagonally periodic TiO2 nanoposts and a vertical p-type metal contact serving as a metallic back-surface reflector together with specialized epitaxial design to minimize parasitic optical losses for efficient light trapping synergistically enable significantly enhanced photovoltaic performance of such ultrathin absorbers, where ∼17.2% solar-to-electric power conversion efficiency under simulated AM1.5G illumination is demonstrated from 420-nm-thick single-junction GaAs solar cells grown in triple-stack epitaxial assemblies.

  16. Effect of sodium acetate on the adhesion to porcine gastric mucin in a Lactococcus lactis strain grown on fructose.

    PubMed

    Kimoto-Nira, Hiromi; Moriya, Naoko; Yamasaki, Seishi; Takenaka, Akio; Suzuki, Chise

    2016-06-01

    The association of lactic acid bacteria with mucosal surfaces plays important roles in the beneficial effects of these bacteria on human health, such as colonization of the gastrointestinal tract for pathogen antagonism. Previously, we found that the adhesion of Lactococcus lactis 7-1 to porcine gastric mucin was higher with fructose than with lactose, galactose or xylose as the carbon source. In this study, we examined the effect of growth conditions on the adhesion of strain 7-1 grown on fructose. Medium components affect the adhesion: the adhesion of strain 7-1 grown with sodium acetate was higher than that without it. The enhancement of adhesion by sodium acetate was not observed under aerobic conditions. Cellular properties grown with or without sodium acetate were characterized: strain 7-1 grown with sodium acetate had similar sugar contents, and different fatty acid composition to those grown without it. Strain 7-1 grown with sodium acetate showed significantly lower cell yield and significantly higher hydrophobicity than those grown without it, which is associated with higher adhesion. Fructose and sodium acetate are frequently used in the food industry; this study may reveal a simple way to enhance the adhesion of lactic acid bacteria by growing them with these substances.

  17. Superparamagnetic iron oxide nanoparticles exert different cytotoxic effects on cells grown in monolayer cell culture versus as multicellular spheroids

    NASA Astrophysics Data System (ADS)

    Theumer, Anja; Gräfe, Christine; Bähring, Franziska; Bergemann, Christian; Hochhaus, Andreas; Clement, Joachim H.

    2015-04-01

    The aim of this study was to investigate the interaction of superparamagnetic iron oxide nanoparticles (SPION) with human blood-brain barrier-forming endothelial cells (HBMEC) in two-dimensional cell monolayers as well as in three-dimensional multicellular spheroids. The precise nanoparticle localisation and the influence of the NP on the cellular viability and the intracellular Akt signalling were studied in detail. Long-term effects of different polymer-coated nanoparticles (neutral fluidMAG-D, anionic fluidMAG-CMX and cationic fluidMAG-PEI) and the corresponding free polymers on cellular viability of HBMEC were investigated by real time cell analysis studies. Nanoparticles exert distinct effects on HBMEC depending on the nanoparticles' surface charge and concentration, duration of incubation and cellular context. The most severe effects were caused by PEI-coated nanoparticles. Concentrations above 25 μg/ml led to increased amounts of dead cells in monolayer culture as well as in multicellular spheroids. On the level of intracellular signalling, context-dependent differences were observed. Monolayer cultures responded on nanoparticle incubation with an increase in Akt phosphorylation whereas spheroids on the whole show a decreased Akt activity. This might be due to the differential penetration and distribution of PEI-coated nanoparticles.

  18. Influence of different yeast cell-wall mutants on performance and protection against pathogenic bacteria (Vibrio campbellii) in gnotobiotically-grown Artemia.

    PubMed

    Soltanian, Siyavash; Dhont, Jean; Sorgeloos, Patrick; Bossier, Peter

    2007-07-01

    A selection of isogenic yeast strains (with deletion for genes involved in cell-wall synthesis) was used to evaluate their nutritional and immunostimulatory characteristics for gnotobiotically-grown Artemia. In the first set of experiments the nutritional value of isogenic yeast strains (effected in mannoproteins, glucan, chitin and cell-wall bound protein synthesis) for gnotobiotically-grown Artemia was studied. Yeast cell-wall mutants were always better feed for Artemia than the isogenic wild type mainly because they supported a higher survival but not a stronger individual growth. The difference in Artemia performance between WT and mutants feeding was reduced when stationary-phase grown cells were used. These results suggest that any mutation affecting the yeast cell-wall make-up is sufficient to improve the digestibility in Artemia. The second set of experiments, investigates the use of a small amount of yeast cells in gnotobiotic Artemia to overcome pathogenicity of Vibrio campbellii (VC). Among all yeast cell strains used in this study, only mnn9 yeast (less cell-wall bound mannoproteins and more glucan and chitin) seems to completely protect Artemia against the pathogen. Incomplete protection against the pathogen was obtained by the gas1 and chs3 mutants, which are lacking the gene for a particular cell-wall protein and chitin synthesis, respectively, resulting in more glucan. The result with the chs3 mutant is of particular interest, as its nutritional value for Artemia is comparable to the wild type. Hence, only with the chs3 strain, in contrast to the gas1 or mnn9 strains, the temporary protection to VC is not concomitant with a better growth performance under non-challenged conditions, suggesting non-interference of general nutritional effects.

  19. Polymer-based protein engineering grown ferrocene-containing redox polymers improve current generation in an enzymatic biofuel cell.

    PubMed

    Campbell, Alan S; Murata, Hironobu; Carmali, Sheiliza; Matyjaszewski, Krzysztof; Islam, Mohammad F; Russell, Alan J

    2016-12-15

    Enzymatic biofuel cells (EBFCs) are capable of generating electricity from physiologically present fuels making them promising power sources for the future of implantable devices. The potential application of such systems is limited, however, by inefficient current generation. Polymer-based protein engineering (PBPE) offers a unique method to tailor enzyme function through tunable modification of the enzyme surface with functional polymers. In this study, we report on the modification of glucose oxidase (GOX) with ferrocene-containing redox polymers to increase current generation efficiency in an enzyme-modified anode. Poly(N-(3-dimethyl(ferrocenyl)methylammonium bromide)propyl acrylamide) (pFcAc) was grown from covalently attached, water-soluble initiator molecules on the surface of GOX in a "grafting-from" approach using atom transfer radical polymerization (ATRP). The covalently-coupled ferrocene-containing polymers on the enzyme surface promoted the effective "wiring" of the GOX active site to an external electrode. The resulting GOX-pFcAc conjugates generated over an order of magnitude increase in current generation efficiency and a 4-fold increase in maximum EBFC power density (≈1.7µWcm(-2)) with similar open circuit voltage (0.27V) compared to native GOX when physically adsorbed onto paddle-shaped electrodes made up of electrospun polyacrylonitrile fibers coated with gold nanoparticles and multi-wall carbon nanotubes. The formation of electroactive enzyme-redox polymer conjugates using PBPE represents a powerful new tool for the improvement of mediated enzyme-based bioelectronics without the need for free redox mediators or anode/cathode compartmentalization.

  20. Role of P13 Kinase Signaling Pathways in Polarity Determination of Human Mammary Epithelial Cells Grown in Three-Dimensional Extracellular Matrix

    DTIC Science & Technology

    2004-09-01

    because cells died once they overexpressed PTEN-GFP construct. The primary consequence of P13K activation is the generation of PIP3 in the membrane...grow in anchorage- independent assays (Figure 3). Our results are consistent with another recent study in that active Akt, when overexpressed ...grown in methyl downstream of P13K might exist to cellulose for 3 weeks and micrographs were control polarity, taken. Now came the question as to which

  1. Proteomic analysis of Clostridium thermocellum ATCC 27405 reveals the upregulation of an alternative transhydrogenase-malate pathway and nitrogen assimilation in cells grown on cellulose.

    PubMed

    Burton, Euan; Martin, Vincent J J

    2012-12-01

    Clostridium thermocellum is a Gram-positive thermophilic anaerobic bacterium with the ability to directly convert cellulosic biomass into useful products such as ethanol and hydrogen. In this study, a quantitative comparative proteomic analysis of the organism was performed to identify proteins and biochemical pathways that are differentially utilized by the organism after growth on cellobiose or cellulose. The cytoplasmic and membrane proteomes of C. thermocellum grown on cellulose or cellobiose were quantitatively compared using a metabolic (15)N isotope labelling method in conjunction with nanoLC-ESI-MS/MS (liquid chromatography - electrospray ionization - tandem mass spectrometry). In total, 1255 proteins were identified in the study, and 129 of those were able to have their relative abundance per cell compared in at least one cellular compartment in response to the substrate provided. This study reveals that cells grown on cellulose increase their abundance of phosphoenolpyruvate carboxykinase while decreasing the abundance of pyruvate dikinase and oxaloacetate decarboxylase, suggesting that the organism diverts carbon flow into a transhydrogenase-malate pathway that can increase the production of the biosynthetic intermediates NADPH and GTP. Glutamate dehydrogenase was also found to have increased abundance in cellulose-grown cells, suggesting that the assimilation of ammonia is upregulated in cells grown on the cellulosic substrates. The results illustrate a mechanism by which C. thermocellum can divert carbon into alternative pathways for the purpose of producing biosynthetic intermediates necessary to respond to growth on cellulose, including transhydrogenation of NADH to NADPH and increased nitrogen assimilation.

  2. The adaptive response of anaerobically grown Saccharomyces cerevisiae to hydrogen peroxide is mediated by the Yap1 and Skn7 transcription factors.

    PubMed

    Beckhouse, Anthony G; Grant, Chris M; Rogers, Peter J; Dawes, Ian W; Higgins, Vincent J

    2008-12-01

    The molecular mechanisms involved in the ability of cells to adapt and respond to differing oxygen tensions are of great interest to the pharmaceutical, medical and fermentation industries. The transcriptional profiles reported in previous studies of cells grown under anaerobic, aerobic and dynamic growth conditions have shown significantly altered responses including induction of genes regulated by the oxidative stress transcription factor Yap1p when oxygen was present. The present study investigated the phenotypic changes that occur in cells when shifted from anaerobic to aerobic growth conditions and it was found through mutant analyses that the elevated activity of Yap1p during the shift was mediated by the phospholipid hydroperoxide-sensing protein encoded by GPX3. Cell viability and growth rate were unaffected even though anaerobically grown cells were found to be hypersensitive to low doses of the oxidative stress-inducing compound hydrogen peroxide (H(2)O(2)). Adaptation to H(2)O(2) treatment was demonstrated to occur when anaerobically grown wild-type cells were aerated for a short time that was reliant on the Yap1p and Skn7p transcription factors.

  3. Biodegradation of bisphenol A and other bisphenols by a gram-negative aerobic bacterium

    SciTech Connect

    Lobos, J.H.; Leib, T.K. ); Tahmun Su )

    1992-06-01

    A novel bacterium designated strain MV1 was isolated from a sludge enrichmet takes from the wastewater treatment plant at a plastics manufacturing facility and shown to degrade 2,2-bis(4-hydroxyphenyl)propane (4,4[prime]-isopropylidenediphenol or bisphenol A). Strain MV1 is a gram-negative, aerobic bacillus that grows on bisphenol A as a sole source of carbon and energy. Total carbon analysis for bisphenol A degradation demonstrated that 60% of the carbon was mineralized to CO[sub 2], 20% was associated with the bacterial cells, and 20% was converted to soluble organic compounds. Metabolic intermediates detected in the culture medium during growth on bisphenol A were identified as 4-hydroxybenzoic acid, 4-hydroxyacetophenone, 2,2-bis(4-hydroxyphenyl)-1-propanol, and 2,3-bis(4-hydroxyphenyl)-1,2-propanediol. Most of the bisphenol A degraded by strain MV1 is cleaved in some way to form 4-hydroxybenzoic acid and 4-hydroxyacetophenone, which are subsequently mineralized or assimilated into cell carbon. In addition, about 20% of the bisphenol A is hydroxylated to form 2,2-bis(4-hydroxyphenyl)-1-propanol, which is slowly biotransformed to 2,3-bis(4-hydroxyphenyl)-1,2-propanediol. Cells that were grown on bisphenol A degraded a variety of bisphenol alkanes, hydroxylated benzoic acids, and hydroxylated acetophenones during resting-cell assays. Transmission electron microscopy of cells grown on bisphenol A revealed lipid storage granules and intracytoplasmic membranes.

  4. Charge photogeneration in hybrid solar cells: A comparison between quantum dots and in situ grown CdS

    NASA Astrophysics Data System (ADS)

    Reynolds, Luke X.; Lutz, Thierry; Dowland, Simon; MacLachlan, Andrew; King, Simon; Haque, Saif A.

    2012-02-01

    We demonstrate that blend films containing poly(3-hexylthiophene-2,5-diyl) and in situ grown CdS display a greater yield of photogenerated charges than a blend containing an equivalent amount of pre-synthesised CdS quantum dots. Moreover, we show that the greater charge yield in the in situ grown films leads to an improvement in device efficiency. The present findings also appear to suggest that charge photogeneration at the CdS/polymer heterojunction is facilitated by the formation of nanoparticle networks as a result of CdS aggregation.

  5. Death rate in a small air-lift loop reactor of vero cells grown on solid microcarriers and in macroporous microcarriers.

    PubMed

    Martens, D E; Nollen, E A; Hardeveld, M; van der Velden-de Groot, C A; de Gooijer, C D; Beuvery, E C; Tramper, J

    1996-01-01

    The death rate of Vero cells grown on Cytodex-3 microcarriers was studied as a function of the gas flow rate in a small air-lift loop reactor. The death rate may be described by first-order death-rate kinetics. The first-order death-rate constant as calculated from the decrease in viable cells, the increase in dead cells and the increase in LDH activity is linear proportional to the gas flow rate, with a specific hypothetical killing volume in which all cells are killed of about 2·10(-3) m(3) liquid per m(3) of air bubbles. In addition, an experiment was conducted in the same air-lift reactor with Vero cells grown inside porous Asahi microcarriers. The specific hypothetical killing volume calculated from this experiment has a value of 3·10(-4) m(3) liquid per m(3) of air bubbles, which shows that the porous microcarriers were at least in part able to protect the cells against the detrimental hydrodynamic forces generated by the bubbles.

  6. Death rate in a small air-lift loop reactor of vero cells grown on solid microcarriers and in macroporous microcarriers.

    PubMed

    Martens, D E; Nollen, E A; Hardeveld, M; Velden-de Groot, C A; Gooijer, C D; Beuvery, E C; Tramper, J

    1997-01-01

    The death rate of Vero cells grown on Cytodex-3 microcarrierswas studied as a function of the gas flow rate in a smallair-lift loop reactor. The death rate may be described byfirst-order death-rate kinetics. The first-order death-rateconstant as calculated from the decrease in viable cells, theincrease in dead cells and the increase in LDH activity islinear proportional to the gas flow rate, with a specifichypothetical killing volume in which all cells are killed ofabout 2.10(-3)m(3) liquid per m(3) of air bubbles.In addition, an experiment was conducted in the sameair-lift reactor with Vero cells grown inside porous Asahimicrocarriers. The specific hypothetical killing volumecalculated from this experiment has a value of 3.10(-4)m(3) liquid per m(3) of air bubbles, which shows thatthe porous microcarriers were at least in part able to protectthe cells against the detrimental hydrodynamic forcesgenerated by the bubbles.

  7. A multiple p-n junction structure obtained from as-grown Czochralski silicon crystals by heat treatment - Application to solar cells

    NASA Technical Reports Server (NTRS)

    Chi, J. Y.; Gatos, H. C.; Mao, B. Y.

    1980-01-01

    Multiple p-n junctions have been prepared in as-grown Czochralski p-type silicon through overcompensation near the oxygen periodic concentration maxima by oxygen thermal donors generated during heat treatment at 450 C. Application of the multiple p-n-junction configuration to photovoltaic energy conversion has been investigated. A new solar-cell structure based on multiple p-n-junctions was developed. Theoretical analysis showed that a significant increase in collection efficiency over the conventional solar cells can be achieved.

  8. Magnesium doping of efficient GaAs and Ga(0.75)In(0.25)As solar cells grown by metalorganic chemical vapor deposition

    NASA Technical Reports Server (NTRS)

    Lewis, C. R.; Ford, C. W.; Werthen, J. G.

    1984-01-01

    Magnesium has been substituted for zinc in GaAs and Ga(0.75)In(0.25)As solar cells grown by metalorganic chemical vapor deposition (MOCVD). Bis(cyclopentadienyl)magnesium (Cp2Mg) is used as the MOCVD transport agent for Mg. Full retention of excellent material quality and efficient cell performance results. The substitution of Mg for Zn would enhance the abruptness and reproducibility of doping profiles, and facilitate high temperature processing and operation, due to the much lower diffusion coefficient of Mg, relative to Zn, in these materials.

  9. MOVPE grown Ga{sub 1{minus}x}In{sub x}As solar cells for GaInP/GaInAs tandem applications

    SciTech Connect

    Dimroth, F.; Lanyi, P.; Schubert, U.; Bett, A.W.

    2000-01-01

    Lattice-mismatched Ga{sub 1{minus}x}In{sub x}As solar cells with an absorption edge between 900 and 1,150 nm have been grown on GaAs substrates. Different graded Ga{sub 1{minus}x}In{sub x}As buffer layers and solar cell structures were evaluated to achieve a good electrical performance of the device. External quantum efficiencies comparable to the best GaAs solar cells were measured. The best 1 cm{sup 2} cell with a bandgap energy of 1.18 eV has an efficient of 22.6% at AM1.5g and a short circuit current density of 36.4 mA/cm{sup 2}. To the authors knowledge, this is the highest reported efficiency for a Ga{sub 0.83}In{sub 0.17}As solar cell.

  10. InGaP/GaAs/InGaAsP triple junction solar cells grown using solid-source molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Sugaya, T.; Makita, K.; Mizuno, H.; Mochizuki, T.; Oshima, R.; Matsubara, K.; Okano, Y.; Niki, S.

    2015-09-01

    We report mechanically stacked InGaP (1.9 eV)/GaAs (1.42 eV)/InGaAsP (1.0 eV) triple junction solar cells fabricated with an advanced bonding technique using Pd nanoparticle arrays. High quality InGaP/GaAs tandem top and InGaAsP bottom cells are grown on GaAs and InP substrates, respectively using solid-source molecular beam epitaxy (MBE). The InGaAsP bottom cell has an open circuit voltage (Voc) of 0.49 V, which indicates that high performance InGaAsP solar cells can be fabricated using solid-source MBE. A fabricated triple junction solar cell has a high efficiency of 25.6% with a high Voc of 2.66 V.

  11. ZnO nanowires array grown on Ga-doped ZnO single crystal for dye-sensitized solar cells.

    PubMed

    Hu, Qichang; Li, Yafeng; Huang, Feng; Zhang, Zhaojun; Ding, Kai; Wei, Mingdeng; Lin, Zhang

    2015-06-23

    High quality ZnO nanowires arrays were homoepitaxial grown on Ga-doped ZnO single crystal (GZOSC), which have the advantages of high conductivity, high carrier mobility and high thermal stability. When it was employed as a photoanode in the DSSCs, the cell exhibited a 1.44% power-conversion efficiency under the illumination of one sun (AM 1.5G). The performance is superior to our ZnO nanowires/FTO based DSSCs under the same condition. This enhanced performance is mainly attributed to the perfect interface between the ZnO nanowires and the GZOSC substrate that contributes to lower carrier scattering and recombination rates compared with that grown on traditional FTO substrate.

  12. ZnO nanowires array grown on Ga-doped ZnO single crystal for dye-sensitized solar cells

    PubMed Central

    Hu, Qichang; Li, Yafeng; Huang, Feng; Zhang, Zhaojun; Ding, Kai; Wei, Mingdeng; Lin, Zhang

    2015-01-01

    High quality ZnO nanowires arrays were homoepitaxial grown on Ga-doped ZnO single crystal (GZOSC), which have the advantages of high conductivity, high carrier mobility and high thermal stability. When it was employed as a photoanode in the DSSCs, the cell exhibited a 1.44% power-conversion efficiency under the illumination of one sun (AM 1.5G). The performance is superior to our ZnO nanowires/FTO based DSSCs under the same condition. This enhanced performance is mainly attributed to the perfect interface between the ZnO nanowires and the GZOSC substrate that contributes to lower carrier scattering and recombination rates compared with that grown on traditional FTO substrate. PMID:26099568

  13. A novel animal-component-free medium for rabies virus production in Vero cells grown on Cytodex 1 microcarriers in a stirred bioreactor.

    PubMed

    Rourou, Samia; van der Ark, Arno; Majoul, Samy; Trabelsi, Khaled; van der Velden, Tiny; Kallel, Héla

    2009-11-01

    Vero cells growth and rabies production in IPT-AF medium, a property animal-component-free medium are described in this work. Kinetics of cell growth and rabies virus (strain LP 2061) production were first conducted in spinner flasks. Over eight independent experiments, Vero cell growth in IPT-AF medium, on 2 g/l Cytodex 1 was consistent. An average Cd (cell division number) of 3.3+/-0.4 and a specific growth rate micro of 0.017+/-0.006 h(-1) were achieved. Such performances were comparable to those obtained in serum-containing medium (MEM+10% FCS). Rabies virus production on Vero cells in IPT-AF medium was also optimised in spinner flasks. The effects of multiplicity of infection (MOI), regulation of glucose level at 1 g/l and cell washing step, were investigated. The highest virus titer was achieved when the cells were infected at an MOI of 0.1; this level was equal to 10(7) FFU/ml. The step of medium exchange before cell infection can be omitted; nevertheless in this case glucose level should be maintained at 1 g/l to avoid a decrease of specific virus productivity. Process optimisation in a 2-l stirred bioreactor pointed out that the aeration mode was the prominent parameter that affected cell growth in IPT-AF medium and on Cytodex 1 microcarriers. An acceptable level of cell density (cell density level of 1.5x10(6) cells/ml) was achieved when cells were grown in batch mode and using headspace aeration. Nevertheless, this aeration mode is not optimal for large-scale culture. The addition of Pluronic F68 at 0.1% at 24 h post inoculation as well as the switch from surface aeration mode to the sparged mode, 2 days after the start of the culture, had markedly improved cell growth performance. A cell density level of 5.5x10(6) cells/ml was reached when cells were grown in a 2-l bioreactor, on 3 g/l Cytodex 1 in IPT-AF medium and using the recirculation culture mode. Cell infection at an MOI of 0.1 and using perfused culture, resulted in a maximal virus titer of 3.5x

  14. Aerobic landfill bioreactor

    SciTech Connect

    Hudgins, Mark P; Bessette, Bernard J; March, John; McComb, Scott T.

    2000-01-01

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  15. Aerobic landfill bioreactor

    SciTech Connect

    Hudgins, Mark P; Bessette, Bernard J; March, John C; McComb, Scott T.

    2002-01-01

    The present invention includes a system of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  16. Aerobic landfill bioreactor

    SciTech Connect

    Hudgins, M.P.; Bessette, B.J.; March, J.; McComb, S.T.

    2000-02-15

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120 F and 140 F in steady state.

  17. Changes in the expression of proteins associated with aerobic glycolysis and cell migration are involved in tumorigenic ability of two glioma cell lines

    PubMed Central

    2012-01-01

    Background The most frequent and malignant brain cancer is glioblastoma multiforme (GBM). In gliomas, tumor progression and poor prognosis are associated with the tumorigenic ability of the cells. U87MG cells (wild-type p53) are known to be tumorigenic in nude mice, but T98G cells (mutant p53) are not tumorigenic. We investigated the proteomic profiling of these two cell lines in order to gain new insights into the mechanisms that may be involved in tumorigenesis. Results We found 24 differentially expressed proteins between T98G and U87MG cells. Gene Ontology supports the notion that over-representation of differentially expressed proteins is involved in glycolysis, cell migration and stress oxidative response. Among those associated with the glycolysis pathway, TPIS and LDHB are up-regulated in U87MG cells. Measurement of glucose consumption and lactate production suggests that glycolysis is more effective in U87MG cells. On the other hand, G6PD expression was 3-fold higher in T98G cells and this may indicate a shift to the pentose-phosphate pathway. Moreover, GRP78 expression was also three-fold higher in T98G than in U87MG cells. Under thapsigargin treatment both cell lines showed increased GRP78 expression and the effect of this agent was inversely correlated to cell migration. Quantitative RT-PCR and immunohistochemistry of GRP78 in patient samples indicated a higher level of expression of GRP78 in grade IV tumors compared to grade I and non-neoplastic tissues, respectively. Conclusions Taken together, these results suggest an important role of proteins involved in key functions such as glycolysis and cell migration that may explain the difference in tumorigenic ability between these two glioma cell lines and that may be extrapolated to the differential aggressiveness of glioma tumors. PMID:22943417

  18. The gene expression profiles of canine mammary cancer cells grown with carcinoma-associated fibroblasts (CAFs) as a co-culture in vitro

    PubMed Central

    2012-01-01

    Background It is supposed that fibroblasts present in tumour microenvironment increase cancer invasiveness and its ability to metastasize but the mechanisms have not been clearly defined yet. Thus, the current study was designed to assess changes in gene expression in five various cancer cell lines grown as a co-culture with the carcinoma-associated fibroblasts (CAFs) in vitro. Results A carcinoma-associated fibroblast cell line was isolated from a canine mammary cancer. Then, a co-culture of cancer cells with the CAFs was established and maintained for 72 hrs. Having sorted the cells, a global gene expression in cancer cells using DNA microarrays was examined. The analysis revealed an up-regulation of 100 genes and a down-regulation of 106 genes in the cancer cells grown as a co-culture with the CAFs in comparison to control conditions. The PANTHER binomial statistics tool was applied to determine statistically over-manifested pathways (p < 0.05). Bulk of the up-regulated genes are involved in the adhesion, the angiogenesis, the epithelial-mesenchymal transition (EMT) and generally take part in the developmental processes. These results were further confirmed using real-time qPCR. Moreover, a wound-healing assay and growth characteristics on Matrigel matrix showed that CAFs increase cancer cell migration and matrix invasion. Conclusion The results of the current study showed that the co-culturing of cancer cells and the CAFs caused significant changes to the cancer gene expression. The presence of the CAFs in a microenvironment of cancer cells promotes adhesion, angiogenesis and EMT. PMID:22453032

  19. InGaP/GaAs Dual-Junction Solar Cell with AlGaAs/GaAs Tunnel Diode Grown on 10° off Misoriented GaAs Substrate

    NASA Astrophysics Data System (ADS)

    Yu, Hung Wei; Chung, Chen Chen; Te Wang, Chin; Nguyen, Hong Quan; Tinh Tran, Binh; Lin, Kung Liang; Dee, Chang Fu; Yeop Majlis, Burhanuddin; Chang, Edward Yi

    2012-08-01

    InGaP/GaAs dual-junction solar cells with different tunnel diodes (TDs) grown on misoriented GaAs substrates are investigated. It is demonstrated that the solar cells with P++-AlGaAs/N++-GaAs TDs grown on 10° off GaAs substrates not only show a higher external quantum efficiency (EQE) but also generate a higher peak current density (Jpeak) at higher concentration ratios (185×) than the solar cells with P++-GaAs/N++-InGaP TDs grown on 6° off GaAs substrates. Furthermore, the cell design with P++-AlGaAs/N++-GaAs TDs grown on 10° off GaAs substrates does not generate a disordered InGaP epitaxial layer during material growth, and thus shows superior current-voltage characteristics.

  20. GaAs Solar Cells Grown by Hydride Vapor-Phase Epitaxy and the Development of GaInP Cladding Layers

    SciTech Connect

    Simon, John; Schulte, Kevin L.; Young, David L.; Haegel, Nancy M.; Ptak, Aaron J.

    2016-01-01

    The high cost of high-efficiency III-V photovoltaic devices currently limits them to niche markets. Hydride vapor-phase epitaxy (HVPE) growth of III-V materials recently reemerged as a low-cost, high-throughput alternative to conventional metal- organic vapor-phase epitaxy (MOVPE) growth of high-efficiency solar cells. Previously, we demonstrated unpassivated HVPEgrown GaAs p-n junctions with good quantum efficiency and high open-circuit voltage (Voc). In this work, we demonstrate the growth of GaInPby HVPE for use as a high-quality surface passivation layer to GaAs solar cells. Solar cells grown with GaInP window layers show significantly improved quantum efficiency compared with unpassivated cells, increasing the short-circuit current (JSC) of these low-cost devices. These results show the potential of low-cost HVPE for the growth of high-quality III-V devices.

  1. Power recovery of radiation damaged MOCVD grown indium phosphide on silicon solar cells through argon-ion laser annealing. Master`s thesis

    SciTech Connect

    Boyer, L.L.

    1996-06-01

    This thesis reports the results of a laser annealing technique used to remove defect sites from radiation damaged indium phosphide on silicon MOCVD grown solar cells. This involves the illumination of damaged solar cells with a continuous wave laser to produce a large forward-biased current. The InP/Si cells were irradiated with 1 MeV electrons to a given fluence, and tested for degradation. Light from an argon laser was used to illuminate four cells with an irradiance of 2.5 W/sq cm, producing a current density 3 to 5 times larger than AMO conditions. Cells were annealed at 19 deg C with the laser and at 25 deg C under AMO conditions. Annealing under laser illumination of n/p-type cells resulted in recovery of 48%. P/n type cells lost 4 to 12% of the assumed degradaton. Annealing under AMO conditions resulted in power recovery of 70% in n/p type cells. P/n-type cells recovered approximately 16% of lost power. Results indicate that significant power recovery results from the annealing of defects within n/p type InP/Si solar cells.

  2. Aminoglycoside-resistant mutants of Pseudomonas aeruginosa deficient in cytochrome d, nitrite reductase, and aerobic transport.

    PubMed Central

    Bryan, L E; Kwan, S

    1981-01-01

    Two gentamicin-resistant mutants of Pseudomonas aeruginosa PAO 503 were selected after ethyl methane sulfonate mutagenesis. Mutant PAO 2403 had significantly increased resistance to aminoglycoside but not to other antibiotics. Mutant PAO 2402 showed a similar spectrum of resistance but of lower magnitude. Both mutants showed no detectable cytochrome d and had a high frequency of reversion to a fully wild-type phenotype. PAO 2403 had a marked decrease and PAO 2402 had a moderate decrease in nitrite reductase activity. Both mutants had reduced uptake of gentamicin and dihydrostreptomycin. Mutant PAO 2403 showed a general decrease in transport rate of cationic compounds, whereas mutant PAO 2402 had only deficient glucose transport. Both mutants showed enhanced rates of glutamine transport and no change in glutamic acid transport. Other components of electron transport and oxidative phosphorylation were normal. These mutants involve ferrocytochrome C551 oxidoreductase formed only on anaerobic growth but illustrate transport defects in aerobically grown cells. PMID:6791588

  3. Rapid detection of a gfp-marked Enterobacter aerogenes under anaerobic conditions by aerobic fluorescence recovery.

    PubMed

    Zhang, Chong; Xing, Xin-Hui; Lou, Kai

    2005-08-15

    A gfp- and kanamycin-resistance gene-containing plasmid pUCGK was successfully constructed and transformed into Enterobacter aerogenes to develop a rapid GFP-based method for quantifying the bacterial concentration under anaerobic conditions for production of biohydrogen. Since the use of GFP as a molecular reporter is restricted by its requirement for oxygen in the development of the fluorophore, fluorescence detection for the fluorescent E. aerogenes grown anaerobically for hydrogen production was performed by developing a method of aerobic fluorescence recovery (AFR) of the anaerobically expressed GFP. By using this AFR method, rapid and non-disruptive cell quantification of E. aerogenes by fluorescence density was achieved for analyzing the hydrogen production process.

  4. Mineralization of Linear Alkylbenzene Sulfonate by a Four-Member Aerobic Bacterial Consortium

    PubMed Central

    Jiménez, Luis; Breen, Alec; Thomas, Nikki; Federle, Thomas W.; Sayler, Gary S.

    1991-01-01

    A bacterial consortium capable of linear alkylbenzene sulfonate (LAS) mineralization under aerobic conditions was isolated from a chemostat inoculated with activated sludge. The consortium, designated KJB, consisted of four members, all of which were gram-negative, rod-shaped bacteria that grew in pairs and short chains. Three isolates had biochemical properties characteristic of Pseudomonas spp.; the fourth showed characteristics of the Aeromonas spp. Cell suspensions were grown together in minimal medium with [14C]LAS as the only carbon source. After 13 days of incubation, more than 25% of the [14C]LAS was mineralized to 14CO2 by the consortium. Pure bacterial cultures and combinations lacking any one member of the KJB bacterial consortium did not mineralize LAS. Three isolates carried out primary biodegradation of the surfactant, and one did not. This study shows that the four bacteria complemented each other and synergistically mineralized LAS, indicating catabolic cooperation among the four consortium members. PMID:16348496

  5. Synergistic effect of dual interfacial modifications with room-temperature-grown epitaxial ZnO and adsorbed indoline dye for ZnO nanorod array/P3HT hybrid solar cell.

    PubMed

    Chen, Dian-Wei; Wang, Ting-Chung; Liao, Wen-Pin; Wu, Jih-Jen

    2013-09-11

    ZnO nanorod (NR)/poly(3-hexylthiophene) (P3HT) hybrid solar cells with interfacial modifications are investigated in this work. The ZnO NR arrays are modified with room-temperature (RT)-grown epitaxial ZnO shells or/and D149 dye molecules prior to the P3HT infiltration. A synergistic effect of the dual modifications on the efficiency of the ZnO NR/P3HT solar cell is observed. The open-circuit voltage and fill factor are considerable improved through the RT-grown ZnO and D149 modifications in sequence on the ZnO NR array, which brings about a 2-fold enhancement of the efficiency of the ZnO NR/P3HT solar cell. We suggested that the more suitable surface of RT-grown ZnO for D149 adsorption, the chemical compatibility of D149 and P3HT, and the elevated conduction band edge of the RT-grown ZnO/D149-modified ZnO NR array construct the superior interfacial morphology and energetics in the RT-grown ZnO/D149-modified ZnO NR/P3HT hybrid solar cell, resulting in the synergistic effect on the cell efficiency. An efficiency of 1.16% is obtained in the RT-grown ZnO/D149-modified ZnO NR/P3HT solar cell.

  6. Exercise, Animal Aerobics, and Interpretation?

    ERIC Educational Resources Information Center

    Oliver, Valerie

    1996-01-01

    Describes an aerobic activity set to music for children that mimics animal movements. Example exercises include walking like a penguin or jumping like a cricket. Stresses basic aerobic principles and designing the program at the level of children's motor skills. Benefits include reaching people who normally don't visit nature centers, and bridging…

  7. Characterization of cellulolytic bacterial cultures grown in different substrates.

    PubMed

    Alshelmani, Mohamed Idris; Loh, Teck Chwen; Foo, Hooi Ling; Lau, Wei Hong; Sazili, Awis Qurni

    2013-01-01

    Nine aerobic cellulolytic bacterial cultures were obtained from the Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Culture (DSMZ) and the American Type Culture Collection (ATCC). The objectives of this study were to characterize the cellulolytic bacteria and to determine the optimum moisture ratio required for solid state fermentation (SSF) of palm kernel cake (PKC). The bacteria cultures were grown on reconstituted nutrient broth, incubated at 30°C and agitated at 200 rpm. Carboxymethyl cellulase, xylanase, and mannanase activities were determined using different substrates and after SSF of PKC. The SSF was conducted for 4 and 7 days with inoculum size of 10% (v/w) on different PKC concentration-to-moisture ratios: 1 : 0.2, 1 : 0.3, 1 : 0.4, and 1 : 0.5. Results showed that Bacillus amyloliquefaciens 1067 DSMZ, Bacillus megaterium 9885 ATCC, Paenibacillus curdlanolyticus 10248 DSMZ, and Paenibacillus polymyxa 842 ATCC produced higher enzyme activities as compared to other bacterial cultures grown on different substrates. The cultures mentioned above also produced higher enzyme activities when they were incubated under SSF using PKC as a substrate in different PKC-to-moisture ratios after 4 days of incubation, indicating that these cellulolytic bacteria can be used to degrade and improve the nutrient quality of PKC.

  8. Broth versus Surface-Grown Cells: Differential Regulation of RsmY/Z Small RNAs in Pseudomonas aeruginosa by the Gac/HptB System

    PubMed Central

    Jean-Pierre, Fabrice; Tremblay, Julien; Déziel, Eric

    2017-01-01

    Two-component systems are capable of profoundly affecting genetic regulation in bacteria by detecting environmental stimuli, allowing them to quickly adapt. In Pseudomonas aeruginosa, the small RNAs (sRNAs) RsmY and RsmZ are under the control of the GacS/A system. They have been described as ones of the major key players in the control of planktonic and surface-associated behaviors. Genetic regulation by these sRNAs is achieved by the titration of the negative post-transcriptional regulator RsmA which affects the expression of over 500 genes. There is increasing evidence pinpointing the importance of RsmY and RsmZ in the planktonic-sessile P. aeruginosa lifestyles switch control. Using swarming motility as a model, we show here that these sRNA are differentially regulated depending on the selected growth conditions (i.e., planktonic versus surface grown-cells). Also, we report that opposite to planktonically grown cells, rsmZ regulation does not implicate the response regulator GacA in swarming cells. Furthermore, we present data indicating that RsmY/Z expression influence swarming motility via the protein HptB which acts as a negative regulator of these sRNAs and that they do not strictly converge to RsmA as previously reported. PMID:28119684

  9. Listeria monocytogenes Internalizes in Romaine Lettuce Grown in Greenhouse Conditions.

    PubMed

    Shenoy, Archana G; Oliver, Haley F; Deering, Amanda J

    2017-04-01

    Listeria monocytogenes has been implicated in a number of outbreaks involving fresh produce, including an outbreak in 2016 resulting from contaminated packaged salads. The persistence and internalization potential of L. monocytogenes in romaine lettuce was evaluated, and the persistence of two L. monocytogenes strains was assessed on three romaine lettuce cultivars. Seeds were germinated, and plants grown in three soil types (i.e., standard potting mix, autoclaved potting mix, and top soil) and sterile soft-top agar for up to 21 days. Average CFU per gram of L. monocytogenes on seeds and plants was calculated from five replicates per harvest day. Up to 8.2 log CFU/g L. monocytogenes persisted on romaine lettuce plants (Braveheart cultivar) grown in soft-top agar, while those grown in commercial potting mix (initial soil aerobic plate count of 4.0 × 10(4) CFU/g) had a final concentration of 5.4 log CFU/g, and autoclaved commercial potting mix had a final concentration of 3.8 ± 0.2 log CFU/g after a 21-day period. Pathogen levels dropped below the limit of detection (2 log CFU/g) by day 18 in 75% topsoil (initial soil aerobic plate count of 4.0 × 10(1) CFU/g); this did not occur in sterile media. Although L. monocytogenes strain differences and presence of a clay coating on seeds did not affect persistence, differences were observed in L. monocytogenes growth and survival among cultivars. To assess internalization, seeds were inoculated with L. monocytogenes expressing green fluorescent protein. Three plants were fixed, paraffin embedded, and sectioned; localization was studied by using standard immunohistochemistry techniques. A total of 539 internalized L. monocytogenes cells were visualized among three 20-day seedlings. L. monocytogenes cells were located in all major tissue types (pith followed by cortex, xylem, phloem, and epidermis). The presence of L. monocytogenes in the plant vasculature suggests potential for transport throughout the plant into edible

  10. Synthesis and application of TiO2 single-crystal nanorod arrays grown by multicycle hydrothermal for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Zhu, Jian-Jing; Zhao, Yu-Long; Zhu, Lei; Gu, Xiu-Quan; Qiang, Ying-Huai

    2014-04-01

    TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells. Vertically aligned TiO2 nanorod arrays (NRs) are grown on the fluorine-doped tin oxide (FTO) substrates by a multicycle hydrothermal synthesis process. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and selected-area electron diffraction (SAED). It is found that dye-sensitized solar cells (DSSCs) assembled by the as-prepared TiO2 single-crystal NRs exhibit different trends under the condition of different nucleation and growth concentrations. Optimum cell performance is obtained with high nucleation concentration and low growth cycle concentration. The efficiency enhancement is mainly attributed to the improved specific surface area of the nanorod.

  11. Production of single-cell oil from prickly-pear juice fermentation by Cryptococcus curvatus grown in batch culture.

    PubMed

    Hassan, M; Blanc, P J; Pareilleux, A; Goma, G

    1994-09-01

    The biomass of Cryptococcus curvatus, an oleaginous yeast, reached 11 g/l and accumulated 46% (w/w) lipid when grown for 35 h in batch culture on diluted (25%) prickly-pear juice. The C:N ratio of the juice was about 50 g/g. The efficiency of substrate conversion was 0.48 g/g for biomass and 0.22 g/g for lipids. The extracted lipids were mainly oleic (18:1) and palmitic (16:0) acids and the quality of pipid approached that of palm oil.

  12. Comparison of single junction AlGaInP and GaInP solar cells grown by molecular beam epitaxy

    SciTech Connect

    Masuda, T; Tomasulo, S; Lang, JR; Lee, ML

    2015-03-07

    We have investigated similar to 2.0 eV (AlxGa1-x)(0.51)In0.49P and similar to 1.9 eV Ga0.51In0.49P single junction solar cells grown on both on-axis and misoriented GaAs substrates by molecular beam epitaxy (MBE). Although lattice-matched (AlxGa1-x)(0.51)In0.49P solar cells are highly attractive for space and concentrator photovoltaics, there have been few reports on the MBE growth of such cells. In this work, we demonstrate open circuit voltages (V-oc) ranging from 1.29 to 1.30 V for Ga0.51In0.49P cells, and 1.35-1.37 V for (AlxGa1-x)(0.51)In0.49P cells. Growth on misoriented substrates enabled the bandgap-voltage offset (W-oc = E-g/q - V-oc) of Ga0.51In0.49P cells to decrease from similar to 575 mV to similar to 565 mV, while that of (AlxGa1-x)(0.51)In0.49P cells remained nearly constant at 620 mV. The constant Woc as a function of substrate offcut for (AlxGa1-x)(0.51)In0.49P implies greater losses from non-radiative recombination compared with the Ga0.51In0.49P devices. In addition to larger Woc values, the (AlxGa1-x)(0.51)In0.49P cells exhibited significantly lower internal quantum efficiency (IQE) values than Ga0.51In0.49P cells due to recombination at the emitter/window layer interface. A thin emitter design is experimentally shown to be highly effective in improving IQE, particularly at short wavelengths. Our work shows that with further optimization of both cell structure and growth conditions, MBE-grown (AlxGa1-x)(0.51)In0.49P will be a promising wide-bandgap candidate material for high-efficiency, lattice-matched multi-junction solar cells. (C) 2015 AIP Publishing LLC.

  13. Comparison of single junction AlGaInP and GaInP solar cells grown by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Masuda, Taizo; Tomasulo, Stephanie; Lang, Jordan R.; Lee, Minjoo Larry

    2015-03-01

    We have investigated ˜2.0 eV (AlxGa1-x)0.51In0.49P and ˜1.9 eV Ga0.51In0.49P single junction solar cells grown on both on-axis and misoriented GaAs substrates by molecular beam epitaxy (MBE). Although lattice-matched (AlxGa1-x)0.51In0.49P solar cells are highly attractive for space and concentrator photovoltaics, there have been few reports on the MBE growth of such cells. In this work, we demonstrate open circuit voltages (Voc) ranging from 1.29 to 1.30 V for Ga0.51In0.49P cells, and 1.35-1.37 V for (AlxGa1-x)0.51In0.49P cells. Growth on misoriented substrates enabled the bandgap-voltage offset (Woc = Eg/q - Voc) of Ga0.51In0.49P cells to decrease from ˜575 mV to ˜565 mV, while that of (AlxGa1-x)0.51In0.49P cells remained nearly constant at 620 mV. The constant Woc as a function of substrate offcut for (AlxGa1-x)0.51In0.49P implies greater losses from non-radiative recombination compared with the Ga0.51In0.49P devices. In addition to larger Woc values, the (AlxGa1-x)0.51In0.49P cells exhibited significantly lower internal quantum efficiency (IQE) values than Ga0.51In0.49P cells due to recombination at the emitter/window layer interface. A thin emitter design is experimentally shown to be highly effective in improving IQE, particularly at short wavelengths. Our work shows that with further optimization of both cell structure and growth conditions, MBE-grown (AlxGa1-x)0.51In0.49P will be a promising wide-bandgap candidate material for high-efficiency, lattice-matched multi-junction solar cells.

  14. Analyses of spatial distributions of sulfate-reducing bacteria and their activity in aerobic wastewater biofilms

    SciTech Connect

    Okabe, Satoshi; Itoh, Tsukasa; Satoh, Hisashi; Watanabe, Yoshimasa

    1999-11-01

    The vertical distribution of sulfate-reducing bacteria (SRB) in aerobic wastewater biofilms grown on rotating disk reactors was investigated by fluorescent in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes. To correlate the vertical distribution of SRB populations with their activity, the microprofiles of O{sub 2}, H{sub 2}S, NO{sub 2}{minus}, NH{sub 2}{sup +}, and pH were measured with microelectrodes. In addition, a cross-evaluation of the FISH and microelectrode analyses was performed by comparing them with culture-based approaches and biogeochemical measurements. In situ hybridization revealed that a relatively high abundance of the probe SRB385-stained cells were evenly distributed throughout the biofilm, even in the toxic surface. The probe SRB660-stained Desulfobulbus spp. were found to be numerically important members of SRB populations. The result of microelectrode measurements showed that a high sulfate-reducing activity was found in a narrow anaerobic zone located about 150 to 300 {micro}m below the biofilm surface and above which an intensive sulfide oxidation zone was found. The biogeochemical measurements showed that elemental sulfur (S{degree}) was an important intermediate of the sulfide reoxidation in such thin wastewater biofilms, which accounted for about 75% of the total S pool in the biofilm. The contribution of an internal Fe-sulfur cycle to the overall sulfur cycle in aerobic wastewater biofilms was insignificant (less than 1%) due to the relatively high sulfate reduction rate.

  15. Properties of Retinal Precursor Cells Grown on Vertically Aligned Multiwalled Carbon Nanotubes Generated for the Modification of Retinal Implant-Embedded Microelectrode Arrays

    PubMed Central

    Johnen, Sandra; Meißner, Frank; Krug, Mario; Baltz, Thomas; Endler, Ingolf; Mokwa, Wilfried; Walter, Peter

    2016-01-01

    Background. To analyze the biocompatibility of vertically aligned multiwalled carbon nanotubes (MWCNT), used as nanomodification to optimize the properties of prostheses-embedded microelectrodes that induce electrical stimulation of surviving retinal cells. Methods. MWCNT were synthesized on silicon wafers. Their growth was achieved by iron particles (Fe) or mixtures of iron-platinum (Fe-Pt) and iron-titanium (Fe-Ti) acting as catalysts. Viability, growth, adhesion, and gene expression of L-929 and retinal precursor (R28) cells were analyzed after nondirect and direct contact. Results. Nondirect contact had almost no influence on cell growth, as measured in comparison to reference materials with defined levels of cytotoxicity. Both cell types exhibited good proliferation properties on each MWCNT-coated wafer. Viability ranged from 95.9 to 99.8%, in which better survival was observed for nonfunctionalized MWCNT generated with the Fe-Pt and Fe-Ti catalyst mixtures. R28 cells grown on the MWCNT-coated wafers showed a decreased gene expression associated with neural and glial properties. Expression of the cell cycle-related genes CCNC, MYC, and TP53 was slightly downregulated. Cultivation on plasma-treated MWCNT did not lead to additional changes. Conclusions. All tested MWCNT-covered slices showed good biocompatibility profiles, confirming that this nanotechnology is a promising tool to improve prostheses bearing electrodes which connect with retinal tissue. PMID:27200182

  16. Comparison of human nasal epithelial cells grown as explant outgrowth cultures or dissociated tissue cultures in vitro.

    PubMed

    Jiao, Jian; Meng, Na; Wang, Hong; Zhang, Luo

    2013-12-01

    The purpose of this study was to compare cell growth characteristics, ciliated cell differentiation, and function of human nasal epithelial cells established as explant outgrowth cultures or dissociated tissue cultures. Human nasal mucosa of the uncinate process was obtained by endoscopy and epithelial cell cultures were established by explant outgrowth or dissociated tissue culture methods. Epithelial cell growth characteristics were observed by inverted phase contrast microscopy. Ciliated cell differentiation was detected by β-tubulin IVand ZO-1 immunocytochemistry. Basal and ATP-stimulated ciliary beat frequency (CBF) was measured using a highspeed digital microscopic imaging system. Both the explant and dissociated tissue cultures established as monolayers with tight junctions and differentiated cell composition, with both types of cultures comprising ciliated and non-ciliated epithelial cells. Fibroblasts were also frequently found in explant cultures but rarely seen in dissociated tissue cultures. In both culture systems, the highest ciliated cell density appeared at 7th-10th culture day and declined with time, with the lifespan of ciliated cells ranging from 14 to 21 days. Overall, 10% of the cells in explant cultures and 20% of the cells in the dissociated tissue cultures were ciliated. These two cultures demonstrated similar ciliary beat frequency values at baseline (7.78 ± 1.99 Hz and 7.91 ± 2.52 Hz, respectively) and reacted equivalently following stimulation with 100 μM ATP. The results of this study indicate that both the explant outgrowth and dissociated tissue culture techniques are suitable for growing well-differentiated nasal ciliated and non-ciliated cells, which have growth characteristics and ciliary activity similar to those of nasal epithelial cells in vivo.

  17. Effect of temperature and pH on ethanol production by free and immobilized cells of Kluyveromyces marxianus grown on Jerusalem artichoke extract

    SciTech Connect

    Bajpai, P.; Margaritis, A.

    1987-01-01

    The effect of temperature and pH on the kinetics of ethanol production by free and calcium alginate immobilized cells of Kluyveromyces marxianus grown on Jerusalem artichoke extract was investigated. With the free cells, the ethanol and biomass yields were relatively constant over the temperature range 25-35 degrees C, but dropped sharply beyond 35 degrees C. Other kinetic parameters, specific growth rate, specific ethanol production rate, and specific total sugar uptake rate were maximum at 35 degrees C. However, with the immobilized cells, ethanol yield remained almost constant in the temperatue range 25-45 degrees C, and the specific ethanol production rate and specific total sugar uptake rate attained their maximum values at 40 degrees C. For the pH range between 3 and 7, the free-cell optimum for growth and product formation was found to be circa pH 5. At this pH, the specific growth rate was 0.35/h and specific ethanol production rate was 2.83 g/g/h. At values higher or lower than pH 5, a sharp decrease in specific ethanol production rate as well as specific growth rate was observed. In comparison, the immobilized cells showed a broad optimum pH profile. The best ethanol production rates were observed between pH 4 and 6. (Refs. 22).

  18. Sludge minimization using aerobic/anoxic treatment technology

    SciTech Connect

    Mines, R.O. Jr.; Kalch, R.S.

    1999-07-01

    The objective of this investigation was to demonstrate through a bench-scale study that using an aerobic/anoxic sequence to treat wastewater and biosolids could significantly reduce the production of biosolids (sludge). A bench-scale activated sludge reactor and anoxic digester were operated for approximately three months. The process train consisted of a completely-mixed aerobic reactor with wasting of biosolids to an anoxic digester for stabilization. The system was operated such that biomass produced in the aerobic activated sludge process was wasted to the anoxic digester; and biomass produced in the anoxic digester was wasted back to the activated sludge process. A synthetic wastewater consisting of bacto-peptone nutrient broth was fed to the liquid process train. Influent and effluent to the aerobic biological process train were analytically tested, as were the contents of mixed liquor in the aerobic reactor and anoxic digester. Overall removal efficiencies for the activated sludge process with regard to COD, TKN, NH{sub 3}-N, and alkalinity averaged 91, 89, 98, and 38%, respectively. The overall average sludge production for the aerobic/anoxic process was 24% less than the overall average sludge production from a conventional activated sludge bench-scale system fed the same substrate and operated under similar mean cell residence times.

  19. Global gene expression profiles of canine macrophages and canine mammary cancer cells grown as a co-culture in vitro

    PubMed Central

    2012-01-01

    Background Solid tumours comprise various cells, including cancer cells, resident stromal cells, migratory haemopoietic cells and other. These cells regulate tumour growth and metastasis. Macrophages constitute probably the most important element of all interactions within the tumour microenvironment. However, the molecular mechanism, that guides tumour environment, still remains unknown. Exploring the underlying molecular mechanisms that orchestrate these phenomena has been the aim of our study. A co-culture of canine mammary cancer cells and macrophages was established and maintained for 72 hrs. Having sorted the cells, gene expression in cancer cells and macrophages, using DNA microarrays, was examined. The results were confirmed using real-time qPCR and confocal microscopy. Moreover, their ability for migration and invasion has been assessed. Results Microarray analysis showed that the up-regulated genes in the cancer cell lines are involved in 15 highly over-manifested pathways. The pathways that drew our diligent attention included: the inflammation pathway mediated by chemokine and cytokine, the Toll receptor signalling pathway and the B cell activation. The up-regulated genes in the macrophages were involved in only 18 significantly over-manifested pathways: the angiogenesis, the p53 pathway feedback loops2 and the Wnt signalling pathway. The microarray analysis revealed that co-culturing of cancer cells with macrophages initiated the myeloid-specific antigen expression in cancer cells, as well as cytokine/chemokine genes expression. This finding was confirmed at mRNA and protein level. Moreover, we showed that macrophages increase cancer migration and invasion. Conclusions The presence of macrophages in the cancer environment induces acquisition of the macrophage phenotype (specific antigens and chemokines/cytokines expression) in cancer cells. We presumed that cancer cells also acquire other myeloid features, such as: capabilities of cell rolling

  20. Genome Sequence of "Pedosphaera parvula" Ellin514, an Aerobic Verrucomicrobial Isolate from Pasture Soil

    SciTech Connect

    Kant, Ravi; Van Passel, Mark W.J.; Palva, Airi; Lucas, Susan; Copeland, A; Lapidus, Alla L.; Glavina Del Rio, Tijana; Dalin, Eileen; Tice, Hope; Bruce, David; Goodwin, Lynne A.; Pitluck, Sam; Chertkov, Olga; Larimer, Frank W; Land, Miriam L; Hauser, Loren John; Brettin, Thomas S; Detter, J. Chris; Han, Cliff; De Vos, Willem M.; Janssen, Peter H.; Smidt, Hauke

    2011-01-01

    Pedosphaera parvula Ellin514 is an aerobically grown verrucomicrobial isolate from pasture soil. In contrast to the high abundance of members of Verrucomicrobia subdivision 3 based on molecular surveys in terrestrial environments, Ellin514 is one of the few cultured representatives of this group.

  1. Lipid content and fatty acid composition of green algae Scenedesmus obliquus grown in a constant cell density apparatus

    NASA Technical Reports Server (NTRS)

    Choi, K. J.; Nakhost, Z.; Barzana, E.; Karel, M.

    1987-01-01

    The lipids of alga Scenedesmus obliquus grown under controlled conditions were separated and fractionated by column and thin-layer chromatography, and fatty acid composition of each lipid component was studied by gas-liquid chromatography (GLC). Total lipids were 11.17%, and neutral lipid, glycolipid and phospholipid fractions were 7.24%, 2.45% and 1.48% on a dry weight basis, respectively. The major neutral lipids were diglycerides, triglycerides, free sterols, hydrocarbons and sterol esters. The glycolipids were: monogalactosyl diglyceride, digalactosyl diglyceride, esterified sterol glycoside, and sterol glycoside. The phospholipids included: phosphatidyl choline, phosphatidyl glycerol and phosphatidyl ethanolamine. Fourteen fatty acids were identified in the four lipid fractions by GLC. The main fatty acids were C18:2, C16:0, C18:3(alpha), C18:1, C16:3, C16:1, and C16:4. Total unsaturated fatty acid and essential fatty acid compositions of the total algal lipids were 80% and 38%, respectively.

  2. Phenolic substance characterization and chemical and cell-based antioxidant activities of 11 lentils grown in the northern United States.

    PubMed

    Xu, Baojun; Chang, Sam K C

    2010-02-10

    Chemical and cellular antioxidant activities and phenolic profiles of 11 lentil cultivars grown in the cool northern parts of the United States were investigated. Individual phenolic compounds, including phenolic acids, flavan-3-ols, flavones, and anthocyanins, were further quantitatively investigated by HPLC. Cellular antioxidant activities (CAA) and peroxyl radical scavenging capacity (PRSC) were evaluated by fluorescence microplate reader. Cultivar Morton exhibited the highest individual flavan-3-ols (catechin and epicatechin) and total flavonoids, as well as the highest antioxidant properties (PRSC and CAA) among all lentils tested. Five phenolic acids of the benzoic types and their derivates (gallic, protocatechuic, 2,3,4-trihydroxybenzoic, p-hydroxybenzoic acid, and protocatechualdehyde) and four phenolic acids of the cinnamic type (chlorogenic, p-coumaric, m-coumaric, and sinapic acid) were detected in all lentil cultivars. Two flavan-3-ols [(+)-catechin and (-)-epicatechin] and one flavone (luteolin) were detected in all lentil cultivars. Among all phenolic compounds detected, sinapic acid was the predominant phenolic acid, and (+)-catechin and (-)-epicatechin were the predominant flavonoids. These results showed that different phenotype lentils possessed considerable variations in their individual phenolic compounds, as well as chemical and cellular antioxidant activities. Caffeic acid, catechin, epicatechin, and total flavonoids significantly (p < 0.05) correlated with peroxyl radical scavenging assay. Cellular antioxidant assay significantly correlated with chemical antioxidant assay ORAC. The results from this study could be very interesting for breeding programs to improve lentils for use as functional foods.

  3. Human RPE Stem Cells Grown into Polarized RPE Monolayers on a Polyester Matrix Are Maintained after Grafting into Rabbit Subretinal Space

    PubMed Central

    Stanzel, Boris V.; Liu, Zengping; Somboonthanakij, Sudawadee; Wongsawad, Warapat; Brinken, Ralf; Eter, Nicole; Corneo, Barbara; Holz, Frank G.; Temple, Sally; Stern, Jeffrey H.; Blenkinsop, Timothy A.

    2014-01-01

    Summary Transplantation of the retinal pigment epithelium (RPE) is being developed as a cell-replacement therapy for age-related macular degeneration. Human embryonic stem cell (hESC) and induced pluripotent stem cell (iPSC)-derived RPE are currently translating toward clinic. We introduce the adult human RPE stem cell (hRPESC) as an alternative RPE source. Polarized monolayers of adult hRPESC-derived RPE grown on polyester (PET) membranes had near-native characteristics. Trephined pieces of RPE monolayers on PET were transplanted subretinally in the rabbit, a large-eyed animal model. After 4 days, retinal edema was observed above the implant, detected by spectral domain optical coherence tomography (SD-OCT) and fundoscopy. At 1 week, retinal atrophy overlying the fetal or adult transplant was observed, remaining stable thereafter. Histology obtained 4 weeks after implantation confirmed a continuous polarized human RPE monolayer on PET. Taken together, the xeno-RPE survived with retained characteristics in the subretinal space. These experiments support that adult hRPESC-derived RPE are a potential source for transplantation therapies. PMID:24511471

  4. Density and length of stomatal and epidermal cells in "living fossil" trees grown under elevated CO 2 and a polar light regime

    NASA Astrophysics Data System (ADS)

    Ogaya, R.; Llorens, L.; Peñuelas, J.

    2011-07-01

    During the Cretaceous and early Tertiary, when the climate was warm and the atmospheric CO 2 concentration ([CO 2]) was at least double that of the present-day, polar forests populated high latitude landmasses. We investigated the density and length of stomata and other epidermal cells of two deciduous and three evergreen "living fossil" tree species representative of these ancient forests. These tree species were grown in a simulated Cretaceous high latitude environment at either ambient (400 ppmv) or elevated (800 ppmv) [CO 2] during four years. After 4 years growing at elevated [CO 2], the leaf stomatal density and index (percentage of leaf epidermal cells that are stomata) of these plants were similar to those of their counterparts growing at ambient [CO 2]. While the CO 2 enrichment only modified the stomatal pore length in two of the five studied species, it increased significantly the overall length of the epidermal cells of all the species, reducing their density. These results revealed that leaf epidermal cells of these "living fossil" species were more sensitive than stomata to an experimental doubling of atmospheric CO 2 concentration.

  5. Development of Lattice-Matched 1.7 eV GalnAsP Solar Cells Grown on GaAs by MOVPE

    SciTech Connect

    Jain, Nikhil; Oshima, Ryuji; France, Ryan; Geisz, John; Norman, Andrew; Dippo, Pat; Levi, Dean; Young, Michelle; Olavarria, Waldo; Steiner, Myles A.

    2016-11-21

    To advance the state-of-the-art in III-V multijunction solar cells towards high concentration efficiencies approaching 50%, development of a high-quality ~1.7 eV second junction solar cell is of key interest for integration in five or more junction devices. Quaternary GalnAsP solar cells grown lattice-matched on GaAs allows bandgap tunability in the range from 1.42 to 1.92 eV and offers an attractive Al-free alternative to conventional AlGaAs solar cells. In this work, we investigate the role of growth temperature towards understanding the optimal growth window for realizing high-quality GalnAsP alloys. We demonstrate bandgap tunability from 1.6 to 1.8 eV in GalnAsP alloys for compositions close to the miscibility gap, while still maintaining lattice-matched condition to GaAs. We perform an in-depth investigation to understand the impact of varying base thickness and doping concentration on the carrier collection and performance of these 1.7 eV GalnAsP solar cells. The photo-response of these cells is found to be very sensitive to p-type zinc dopant incorporation in the base layer. We demonstrate prototype 1.7 eV GalnAsP solar cell designs that leverage enhanced depletion width as an effective method to overcome this issue and boost long-wavelength carrier collection. Short-circuit current density (JSC) measured in field-aided devices were as high as 17.25 m A/cm2. The best GalnAsP solar cell in this study achieved an efficiency of 17.2% with a JSC of 17 m A/cm2 and a fill-factor of 86.4%. The corresponding open-circuit voltage (VOC) 1.7 eV measured on this cell represents the highest Voc reported for a 1.7 eV GalnAsP solar cell. These initial cell results are encouraging and highlight the potential of Al-free GalnAsP solar cells for integration in the next generation of III-V multijunction solar cells.

  6. Recombination current in AlGaAs/GaAs superlattice solar-cells grown by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Kawaharazuka, A.; Nishinaga, J.; Horikoshi, Y.

    2015-09-01

    We investigate the effect of the recombination current of p-i-n junction solar-cells. We develop a simple evaluation method of the recombination and diffusion current component of the solar-cells based on the measured three characteristic values: short circuit current, open circuit voltage, and fill factor without the knowledge in the details of the device structure. The advantage of the developed technique is its simplicity and wide applicability to various p-i-n junction solar-cells. We apply the method to GaAs bulk and AlGaAs/GaAs superlattice solar-cells. Obtained parameters well reproduce the whole current-voltage characteristics. The diode current is almost dominated by the recombination current at the maximum-output voltage for both GaAs bulk and superlattice cells. The higher contribution of the recombination current in the superlattice solar-cell is due to the quality of the AlGaAs barriers and the AlGaAs/GaAs interfaces. This result indicates that the good crystalline quality is important to enhance the efficiency of the solar-cells.

  7. The light intensity under which cells are grown controls the type of peripheral light-harvesting complexes that are assembled in a purple photosynthetic bacterium

    SciTech Connect

    Brotosudarmo, Tatas H. P.; Collins, Aaron M.; Gall, Andrew; Roszak, Aleksander W.; Gardiner, Alastair T.; Blankenship, Robert E.; Cogdell, Richard J.

    2011-11-15

    The differing composition of LH2 (peripheral light-harvesting) complexes present in Rhodopseudomonas palustris 2.1.6 have been investigated when cells are grown under progressively decreasing light intensity. Analysis of the absorption spectra reveals there must be more than two types of LH2 complexes present. Purified HL (high-light) and LL (low-light) LH2 complexes have mixed apoprotein compositions. The HL complexes contain PucABa and PucABb apoproteins. The LL complexes contain PucABa, PucABd and PucBb-only apoproteins. This mixed apoprotein composition can explain their resonance Raman spectra.

  8. Growth of lattice-matched GaInAsP grown on vicinal GaAs(001) substrates within the miscibility gap for solar cells

    NASA Astrophysics Data System (ADS)

    Oshima, Ryuji; France, Ryan M.; Geisz, John F.; Norman, Andrew G.; Steiner, Myles A.

    2017-01-01

    The growth of quaternary Ga0.68In0.32As0.35P0.65 by metal-organic vapor phase epitaxy is very sensitive to growth conditions because the composition is within a miscibility gap. In this investigation, we fabricated 1 μm-thick lattice-matched GaInAsP films grown on GaAs(001) for application to solar cells. The growth temperature and substrate miscut are varied in order to characterize the effect of the surface diffusion of adatoms on the material quality of alloys. Transmission electron microscopy and two-dimensional in-situ multi-beam optical stress determine that growth temperatures of 650 °C and below enhance the formation of the CuPtB atomic ordering and suppress material decomposition, which is found to occur at the growth surface. The root-mean-square (RMS) roughness is reduced from 33.6 nm for 750 °C to 1.62 nm for 650 °C, determined by atomic force microscopy. Initial investigations show that the RMS roughness can be further reduced using increased miscut angle, and substrates miscut toward (111)A, leading to an RMS roughness of 0.56 nm for the sample grown at 600 °C on GaAs miscut 6° toward (111)A. Using these conditions, we fabricate an inverted hetero-junction 1.62 eV Ga0.68In0.32As0.35P0.65 solar cell without an anti-reflection coating with a short-circuit current density, open-circuit voltage, fill factor, and efficiency of 12.23 mA/cm2, 1.12 V, 86.18%, and 11.80%, respectively.

  9. Growth of lattice-matched GaInAsP grown on vicinal GaAs(001) substrates within the miscibility gap for solar cells

    SciTech Connect

    Oshima, Ryuji; France, Ryan M.; Geisz, John F.; Norman, Andrew G.; Steiner, Myles A.

    2017-01-01

    The growth of quaternary Ga0.68In0.32As0.35P0.65 by metal-organic vapor phase epitaxy is very sensitive to growth conditions because the composition is within a miscibility gap. In this investigation, we fabricated 1 um-thick lattice-matched GaInAsP films grown on GaAs(001) for application to solar cells. The growth temperature and substrate miscut are varied in order to characterize the effect of the surface diffusion of adatoms on the material quality of alloys. Transmission electron microscopy and two-dimensional in-situ multi-beam optical stress determine that growth temperatures of 650 degrees C and below enhance the formation of the CuPtB atomic ordering and suppress material decomposition, which is found to occur at the growth surface. The root-mean-square (RMS) roughness is reduced from 33.6 nm for 750 degrees C to 1.62 nm for 650 degrees C, determined by atomic force microscopy. Initial investigations show that the RMS roughness can be further reduced using increased miscut angle, and substrates miscut toward (111)A, leading to an RMS roughness of 0.56 nm for the sample grown at 600 degrees C on GaAs miscut 6 degrees toward (111)A. Using these conditions, we fabricate an inverted hetero-junction 1.62 eV Ga0.68In0.32As0.35P0.65 solar cell without an anti-reflection coating with a short-circuit current density, open-circuit voltage, fill factor, and efficiency of 12.23 mA/cm2, 1.12 V, 86.18%, and 11.80%, respectively.

  10. SIMS Characterization of Amorphous Silicon Solar Cells Grown by Hot-Wire Chemical Vapor Deposition on Stainless Steel

    SciTech Connect

    Reedy, R. C.; Wang, Q.; Moutinho, H.; Iwaniczko, E.; Mahan, A. H.

    2000-01-01

    This paper is intended to be an overview of some of the challenges that must be overcome when characterizing amourphous-silicon solar cell devices by the secondary ion mass spectrometry (SIMS) technique.

  11. Differences In Early T-Cell Signaling In Cultures Grown In a Rotating Clinostat vs. Static Controls

    NASA Technical Reports Server (NTRS)

    Alexamder. M.; Nelman-Gonzales, M.; Penkala, J.; Sams, C.

    1999-01-01

    Altered gravity has previously been demonstrated to be a stress that can influence components of the immune system. Specifically, T-cell activation has been shown to be affected by changes in gravity, exhibiting a decrease in proliferative response to in vitro stimulation in microgravity. Subsequent ground based studies utilizing a rotating clinostat to model some of the effects of microgravity have been consistent with earlier flight based experiments. These ground and flight experiments have examined T-cell activation by measuring various responses including production of cytokines, DNA synthesis and the production of various cell surface activation markers. These indicators of T-cell activation were measured anywhere from 4 to 72 hours after stimulation. Prior to the work described here, the initial signaling events in T-cell activation had not been directly examined. The goal of this project was to determine how the process of early signal transduction was affected by growth in a rotating clinostat. Here we directly show a defect in signaling from TCR to MAPK in purified peripheral T-cells activated in the clinostat by OKT3/antiCD28 coated microbeads as compared to static controls.

  12. Upregulation of cell proliferation via Shc and ERK1/2 MAPK signaling in SaOS-2 osteoblasts grown on magnesium alloy surface coating with tricalcium phosphate.

    PubMed

    Jiang, Tianlong; Guo, Lei; Ni, Shenghui; Zhao, Yuyan

    2015-04-01

    Magnesium (Mg) alloys have been demonstrated to be viable orthopedic implants because of mechanical and biocompatible properties similar to natural bone. In order to improve its osteogenic properties, a porous β-tricalcium phosphate (β-TCP) was coated on the Mg-3AI-1Zn alloy by alkali-heat treatment technique. The human bone-derived cells (SaOS-2) were cultured on (β-TCP)-Mg-3AI-1Zn in vitro, and the osteoblast response, the morphology and the elements on this alloy surface were investigated. Also, the regulation of key intracellular signalling proteins was investigated in the SaOS-2 cells cultured on alloy surface. The results from scanning electron microscope and immunofluorescence staining demonstrated that (β-TCP)-Mg-3AI-1Zn induced significant osteogenesis. SaOS-2 cell proliferation was improved by β-TCP coating. Moreover, the (β-TCP)-Mg-3AI-1Zn surface induced activation of key intracellular signalling proteins in SaOS-2 cells. We observed an enhanced activation of Src homology and collagen (Shc), a common point of integration between bone morphogenetic protein 2, and the Ras/mitogen-activated protein kinase (MAPK) pathway. ERK1/2 MAP kinase activation was also upregulated, suggesting a role in mediating osteoblastic cell interactions with biomaterials. The signalling pathway involving c-fos (member of the activated protein-1) was also shown to be upregulated in osteoblasts cultured on the (β-TCP)-Mg-3AI-1Zn. These results suggest that β-TCP coating may contribute to successful osteoblast function on Mg alloy surface. (β-TCP)-Mg-3AI-1Zn may upregulate cell proliferation via Shc and ERK1/2 MAPK signaling in SaOS-2 osteoblasts grown on Mg alloy surface.

  13. Does vector-free gravity simulate microgravity? Functional and morphologic attributes of clinorotated nerve and muscle grown in cell culture

    NASA Technical Reports Server (NTRS)

    Gruener, R.; Hoeger, G.

    1988-01-01

    Cocultured Xenopus neurons and myocytes were subjected to non-vectorial gravity by clinostat rotation to determine if microgravity, during space flights, may affect cell development and communications. Clinorotated cells showed changes consistent with the hypothesis that cell differentiation, in microgravity, is altered by interference with cytoskeleton-related mechanisms. We found: increases in the myocyte and its nuclear area, "fragmentation" of nucleoli, appearance of neuritic "aneurysms", decreased growth in the presence of "trophic" factors, and decreased yolk utilization. The effects were most notable at 1-10 rpm and depended on the onset and duration of rotation. Some parameters returned to near control values within 48 hrs after cessation of rotation. Cells from cultures rotated at higher speeds (>50 rpm) appeared comparable to controls. Compensation by centrifugal forces may account for this finding. Our data are consistent, in principle, with effects on other, flighted cells and suggest that "vector-free" gravity may simulate certain aspects of microgravity. The distribution of acetylcholine receptor aggregates, on myocytes, was also altered. This indicates that brain development, in microgravity, may also be affected.

  14. Changes of Photosynthetic Behaviors and Photoprotection during Cell Transformation and Astaxanthin Accumulation in Haematococcus pluvialis Grown Outdoors in Tubular Photobioreactors.

    PubMed

    Zhang, Litao; Su, Fang; Zhang, Chunhui; Gong, Fengying; Liu, Jianguo

    2016-12-26

    The cell transformation from green motile cells to non-motile cells and astaxanthin accumulation can be induced in the green alga Haematococcus pluvialis cultured outdoors. In the initial 3 d of incubation (cell transformation phase), light absorption and photosynthetic electron transport became more efficient. After five days of incubation (astaxanthin accumulation phase), the light absorption per active reaction center (ABS/RC) increased, but the efficiency of electron transport (ψo) and the quantum yield of electron transport (φEo) decreased with increased time, indicating that the capacity of photosynthetic energy utilization decreased significantly during astaxanthin accumulation, leading to an imbalance between photosynthetic light absorption and energy utilization. It would inevitably aggravate photoinhibition under high light, e.g., at midday. However, the level of photoinhibition in H. pluvialis decreased as the incubation time increased, which is reflected by the fact that Fv/Fm determined at midday decreased significantly in the initial 3 d of incubation, but was affected very little after seven days of incubation, compared with that determined at predawn. This might be because the non-photochemical quenching, plastid terminal oxidase, photosystem I cyclic electron transport, defensive enzymes and the accumulated astaxanthin can protect cells against photoinhibition.

  15. Changes of Photosynthetic Behaviors and Photoprotection during Cell Transformation and Astaxanthin Accumulation in Haematococcus pluvialis Grown Outdoors in Tubular Photobioreactors

    PubMed Central

    Zhang, Litao; Su, Fang; Zhang, Chunhui; Gong, Fengying; Liu, Jianguo

    2016-01-01

    The cell transformation from green motile cells to non-motile cells and astaxanthin accumulation can be induced in the green alga Haematococcus pluvialis cultured outdoors. In the initial 3 d of incubation (cell transformation phase), light absorption and photosynthetic electron transport became more efficient. After five days of incubation (astaxanthin accumulation phase), the light absorption per active reaction center (ABS/RC) increased, but the efficiency of electron transport (ψo) and the quantum yield of electron transport (φEo) decreased with increased time, indicating that the capacity of photosynthetic energy utilization decreased significantly during astaxanthin accumulation, leading to an imbalance between photosynthetic light absorption and energy utilization. It would inevitably aggravate photoinhibition under high light, e.g., at midday. However, the level of photoinhibition in H. pluvialis decreased as the incubation time increased, which is reflected by the fact that Fv/Fm determined at midday decreased significantly in the initial 3 d of incubation, but was affected very little after seven days of incubation, compared with that determined at predawn. This might be because the non-photochemical quenching, plastid terminal oxidase, photosystem I cyclic electron transport, defensive enzymes and the accumulated astaxanthin can protect cells against photoinhibition. PMID:28035956

  16. Aerobic biotransformation of N-nitrosodimethylamine and N-nitrodimethylamine in methane and benzene amended soil columns

    NASA Astrophysics Data System (ADS)

    Weidhaas, Jennifer; Dupont, R. Ryan

    2013-07-01

    Aerobic biotransformation of N-nitrosodimethylamine (NDMA), an emerging contaminant of concern, and its structural analog N-nitrodimethylamine (DMN), was evaluated in benzene and methane amended groundwater passed through laboratory scale soil columns. Competitive inhibition models were used to model the kinetics for NDMA and DMN cometabolism accounting for the concurrent degradation of the growth and cometabolic substrates. Transformation capacities for NDMA and DMN with benzene (13 and 23 μg (mg cells)- 1) and methane (0.14 and 8.4 μg (mg cells)- 1) grown cultures, respectively are comparable to those presented in the literature, as were first order endogenous decay rates estimated to be 2.1 × 10- 2 ± 1.7 × 10- 3 d- 1 and 6.5 × 10- 1 ± 7.1 × 10- 1 d- 1 for the methane and benzene amended cultures, respectively. These studies highlight possible attenuation mechanisms and rates for NDMA and DMN biotransformation in aerobic aquifers undergoing active remediation, natural attenuation or managed aquifer recharge with treated wastewater (i.e., reclaimed water).

  17. Noise Levels during Aerobics and the Potential Effects on Distortion Product Otoacoustic Emissions

    ERIC Educational Resources Information Center

    Torre, Peter, III; Howell, Jennifer C.

    2008-01-01

    The purpose of this study was to measure noise levels during aerobics classes and to examine how outer hair cell (OHC) function, using distortion product otoacoustic emissions (DPOAEs), may be affected by this exposure. Fifty individuals (48 women and 2 men, ages 19-41 years) participated in 50-min aerobics classes. Noise levels were measured…

  18. Comparison of single junction AlGaInP and GaInP solar cells grown by molecular beam epitaxy

    SciTech Connect

    Masuda, Taizo Tomasulo, Stephanie; Lang, Jordan R.; Lee, Minjoo Larry

    2015-03-07

    We have investigated ∼2.0 eV (Al{sub x}Ga{sub 1−x}){sub 0.51}In{sub 0.49}P and ∼1.9 eV Ga{sub 0.51}In{sub 0.49}P single junction solar cells grown on both on-axis and misoriented GaAs substrates by molecular beam epitaxy (MBE). Although lattice-matched (Al{sub x}Ga{sub 1−x}){sub 0.51}In{sub 0.49}P solar cells are highly attractive for space and concentrator photovoltaics, there have been few reports on the MBE growth of such cells. In this work, we demonstrate open circuit voltages (V{sub oc}) ranging from 1.29 to 1.30 V for Ga{sub 0.51}In{sub 0.49}P cells, and 1.35–1.37 V for (Al{sub x}Ga{sub 1−x}){sub 0.51}In{sub 0.49}P cells. Growth on misoriented substrates enabled the bandgap-voltage offset (W{sub oc} = E{sub g}/q − V{sub oc}) of Ga{sub 0.51}In{sub 0.49}P cells to decrease from ∼575 mV to ∼565 mV, while that of (Al{sub x}Ga{sub 1−x}){sub 0.51}In{sub 0.49}P cells remained nearly constant at 620 mV. The constant W{sub oc} as a function of substrate offcut for (Al{sub x}Ga{sub 1−x}){sub 0.51}In{sub 0.49}P implies greater losses from non-radiative recombination compared with the Ga{sub 0.51}In{sub 0.49}P devices. In addition to larger W{sub oc} values, the (Al{sub x}Ga{sub 1−x}){sub 0.51}In{sub 0.49}P cells exhibited significantly lower internal quantum efficiency (IQE) values than Ga{sub 0.51}In{sub 0.49}P cells due to recombination at the emitter/window layer interface. A thin emitter design is experimentally shown to be highly effective in improving IQE, particularly at short wavelengths. Our work shows that with further optimization of both cell structure and growth conditions, MBE-grown (Al{sub x}Ga{sub 1−x}){sub 0.51}In{sub 0.49}P will be a promising wide-bandgap candidate material for high-efficiency, lattice-matched multi-junction solar cells.

  19. Maslinic Acid, a Triterpene from Olive, Affects the Antioxidant and Mitochondrial Status of B16F10 Melanoma Cells Grown under Stressful Conditions

    PubMed Central

    Mokhtari, Khalida; Rufino-Palomares, Eva E.; Pérez-Jiménez, Amalia; Reyes-Zurita, Fernando J.; Figuera, Celeny; García-Salguero, Leticia; Medina, Pedro P.; Peragón, Juan; Lupiáñez, José A.

    2015-01-01

    Maslinic acid (MA) is a natural compound whose structure corresponds to a pentacyclic triterpene. It is abundant in the cuticular lipid layer of olives. MA has many biological and therapeutic properties related to health, including antitumor, anti-inflammatory, antimicrobial, antiparasitic, antihypertensive, and antioxidant activities. However, no studies have been performed to understand the molecular mechanism induced by this compound in melanoma cancer. The objective of this study was to examine the effect of MA in melanoma (B16F10) cells grown in the presence or absence of fetal bovine serum (FBS). We performed cell proliferation measurements, and the reactive oxygen species (ROS) measurements using dihydrorhodamine 123 (DHR 123) and activities of catalase, glucose 6-phosphate dehydrogenase, glutathione S-transferase, and superoxide dismutase. These changes were corroborated by expression assays. FBS absence reduced cell viability decreasing IC50 values of MA. The DHR 123 data showed an increase in the ROS level in the absence of FBS. Furthermore, MA had an antioxidant effect at lower assayed levels measured as DHR and antioxidant defense. However, at higher dosages MA induced cellular damage by apoptosis as seen in the results obtained. PMID:26236377

  20. High-Quality Perovskite Films Grown with a Fast Solvent-Assisted Molecule Inserting Strategy for Highly Efficient and Stable Solar Cells.

    PubMed

    Yuan, Shuai; Qiu, Zhiwen; Gao, Chaomin; Zhang, Hailiang; Jiang, Yanan; Li, Cuncheng; Yu, Jinghua; Cao, Bingqiang

    2016-08-31

    The performance of organolead halide perovskites based solar cells has been enhanced dramatically due to the morphology control of the perovskite films. In this paper, we present a fast solvent-assisted molecule inserting (S-AMI) strategy to grow high-quality perovskite film, in which the methylammonium iodide/2-propanol (MAI/IPA) solution is spin-coated onto a dimethylformamide (DMF) wetted mixed lead halide (PbX2) precursor film. The DMF can help the inserting of MAI molecules into the PbX2 precursor film and provide a solvent environment to help the grain growth of the perovskite film. The perovskite film grown by the S-AMI approach shows large and well-oriented grains and long carrier lifetime due to the reduced grain boundary. Solar cells constructed with these perovskite films yield an average efficiency over 17% along with a high average fill factor of 80%. Moreover, these unsealed solar cell devices exhibit good stability in an ambient atmosphere.

  1. Relationship between acid tolerance and cell membrane in Bifidobacterium, revealed by comparative analysis of acid-resistant derivatives and their parental strains grown in medium with and without Tween 80.

    PubMed

    Yang, Xu; Hang, Xiaomin; Zhang, Min; Liu, Xianglong; Yang, Hong

    2015-06-01

    The acid tolerance is particularly important for bifidobacteria to function as probiotics because they usually encounter acidic environments in food products and gastrointestinal tract passage. In this study, two acid-resistant derivatives Bifidobacterium longum JDY1017dpH and Bifidobacterium breve BB8dpH, which displayed a stable acid-resistant phenotype, were generated. The relationship between acid tolerance and cell membrane was investigated by comparing the two acid-resistant derivatives and their parental strains grown in medium with and without Tween 80. The fold increase in acid tolerance of the two acid-resistant derivatives relative to their parental strains was much higher when cells were grown in medium with Tween 80 (10(4) ~ 10(5)-fold) than without Tween 80 (181- and 245-fold). Moreover, when cells were grown in medium with Tween 80, the two acid-resistant derivatives exhibited more C18:1 and cycC19:0, higher mean fatty acid chain length, lower membrane fluidity, and higher expression of cfa gene encoding cyclopropane fatty acid synthase than their parental strains. No significant differences in cell membrane were observed between the two acid-resistant derivatives and their parental strains when cells were grown in medium without Tween 80. The present study revealed that, when cells were grown in medium with Tween 80, the significant fold increase in acid tolerance of the two acid-resistant derivatives was mainly ascribed to the pronounced changes in cell membrane compared with their parental strains. Results presented here could provide a basis for developing new strategies of cell membrane modification to enhance acid tolerance in bifidobacteria.

  2. Hap4p overexpression in glucose-grown Saccharomyces cerevisiae induces cells to enter a novel metabolic state

    PubMed Central

    Lascaris, Romeo; Bussemaker, Harmen J; Boorsma, André; Piper, Matt; van der Spek, Hans; Grivell, Les; Blom, Jolanda

    2003-01-01

    Background Metabolic and regulatory gene networks generally tend to be stable. However, we have recently shown that overexpression of the transcriptional activator Hap4p in yeast causes cells to move to a state characterized by increased respiratory activity. To understand why overexpression of HAP4 is able to override the signals that normally result in glucose repression of mitochondrial function, we analyzed in detail the changes that occur in these cells. Results Whole-genome expression profiling and fingerprinting of the regulatory activity network show that HAP4 overexpression provokes changes that also occur during the diauxic shift. Overexpression of HAP4, however, primarily acts on mitochondrial function and biogenesis. In fact, a number of nuclear genes encoding mitochondrial proteins are induced to a greater extent than in cells that have passed through a normal diauxic shift: in addition to genes required for mitochondrial energy conservation they include genes encoding mitochondrial ribosomal proteins. Conclusions We show that overproduction of a single nuclear transcription factor enables cells to move to a novel state that displays features typical of, but clearly not identical to, other derepressed states. PMID:12537548

  3. Role of surface-electrical properties on the cell-viability of carbon thin films grown in nanodomain morphology

    NASA Astrophysics Data System (ADS)

    Javid, Amjed; Kumar, Manish; Yoon, Seokyoung; Lee, Jung Heon; Tajima, Satomi; Hori, Masaru; Geon Han, Jeon

    2016-07-01

    Carbon thin films, having a combination of unique physical and chemical properties, exhibit an interesting biocompatibility and biological response to living entities. Here, the carbon films are developed in the morphology form of nano-domains with nanoscale inter-domain separations, tuned by plasma conditions in the facing target magnetron sputtering process. The wettability and surface energy are found to have a close relation to the inter-domain separations. The chemical structure of carbon films exhibited the relative enhancement of sp3 in comparison to sp2 with the increase of domain separations. The cell-viability of these films shows promising results for L929 mouse fibroblast and Saos-2 bone cells, when inter-domain separation is increased. Electrical conductivity and surface energy are identified to play the key role in different time-scales during the cell-proliferation process. The contribution from electrical conductivity is dominant in the beginning of the cultivation, whereas with the passage of time (~3-5 d) the surface energy takes control over conductivity to enhance the cell proliferation.

  4. Development of high-bandgap AlGaInP solar cells grown by organometallic vapor-phase epitaxy

    DOE PAGES

    Perl, Emmett E.; Simon, John; Geisz, John F.; ...

    2016-03-29

    AlGaInP solar cells with bandgaps between 1.9 and 2.2 eV are investigated for use in next-generation multijunction photovoltaic devices. This quaternary alloy is of great importance to the development of III-V solar cells with five or more junctions and for cells optimized for operation at elevated temperatures because of the high bandgaps required in these designs. In this work, we explore the conditions for the organometallic vapor-phase epitaxy growth of AlGaInP and study their effects on cell performance. Initial efforts focused on developing ~2.0-eV AlGaInP solar cells with a nominal aluminum composition of 12%. Under the direct spectrum at 1000more » W/m2 (AM1.5D), the best of these samples had an open-circuit voltage of 1.59 V, a bandgap-voltage offset of 440 mV, a fill factor of 88.0%, and an efficiency of 14.8%. We then varied the aluminum composition of the alloy from 0% to 24% and were able to tune the bandgap of the AlGaInP layers from ~1.9 to ~2.2 eV. Furthermore, while the samples with a higher aluminum composition exhibited a reduced quantum efficiency and increased bandgap-voltage offset, the bandgap-voltage offset remained at 500 mV or less, up to a bandgap of ~2.1 eV.« less

  5. Development of high-bandgap AlGaInP solar cells grown by organometallic vapor-phase epitaxy

    SciTech Connect

    Perl, Emmett E.; Simon, John; Geisz, John F.; Olavarria, Waldo; Young, Michelle; Duda, Anna; Friedman, Daniel J.; Steiner, Myles A.

    2016-03-29

    AlGaInP solar cells with bandgaps between 1.9 and 2.2 eV are investigated for use in next-generation multijunction photovoltaic devices. This quaternary alloy is of great importance to the development of III-V solar cells with five or more junctions and for cells optimized for operation at elevated temperatures because of the high bandgaps required in these designs. In this work, we explore the conditions for the organometallic vapor-phase epitaxy growth of AlGaInP and study their effects on cell performance. Initial efforts focused on developing ~2.0-eV AlGaInP solar cells with a nominal aluminum composition of 12%. Under the direct spectrum at 1000 W/m2 (AM1.5D), the best of these samples had an open-circuit voltage of 1.59 V, a bandgap-voltage offset of 440 mV, a fill factor of 88.0%, and an efficiency of 14.8%. We then varied the aluminum composition of the alloy from 0% to 24% and were able to tune the bandgap of the AlGaInP layers from ~1.9 to ~2.2 eV. Furthermore, while the samples with a higher aluminum composition exhibited a reduced quantum efficiency and increased bandgap-voltage offset, the bandgap-voltage offset remained at 500 mV or less, up to a bandgap of ~2.1 eV.

  6. Biofilm-Grown Burkholderia cepacia Complex Cells Survive Antibiotic Treatment by Avoiding Production of Reactive Oxygen Species

    PubMed Central

    Van Acker, Heleen; Sass, Andrea; Bazzini, Silvia; De Roy, Karen; Udine, Claudia; Messiaen, Thomas; Riccardi, Giovanna; Boon, Nico; Nelis, Hans J.; Mahenthiralingam, Eshwar; Coenye, Tom

    2013-01-01

    The presence of persister cells has been proposed as a factor in biofilm resilience. In the present study we investigated whether persister cells are present in Burkholderia cepacia complex (Bcc) biofilms, what the molecular basis of antimicrobial tolerance in Bcc persisters is, and how persisters can be eradicated from Bcc biofilms. After treatment of Bcc biofilms with high concentrations of various antibiotics often a small subpopulation survived. To investigate the molecular mechanism of tolerance in this subpopulation, Burkholderia cenocepacia biofilms were treated with 1024 µg/ml of tobramycin. Using ROS-specific staining and flow cytometry, we showed that tobramycin increased ROS production in treated sessile cells. However, approximately 0.1% of all sessile cells survived the treatment. A transcriptome analysis showed that several genes from the tricarboxylic acid cycle and genes involved in the electron transport chain were downregulated. In contrast, genes from the glyoxylate shunt were upregulated. These data indicate that protection against ROS is important for the survival of persisters. To confirm this, we determined the number of persisters in biofilms formed by catalase mutants. The persister fraction in ΔkatA and ΔkatB biofilms was significantly reduced, confirming the role of ROS detoxification in persister survival. Pretreatment of B. cenocepacia biofilms with itaconate, an inhibitor of isocitrate lyase (ICL), the first enzyme in the glyoxylate shunt, reduced the persister fraction approx. 10-fold when the biofilms were subsequently treated with tobramycin. In conclusion, most Bcc biofilms contain a significant fraction of persisters that survive treatment with high doses of tobramycin. The surviving persister cells downregulate the TCA cycle to avoid production of ROS and at the same time activate an alternative pathway, the glyoxylate shunt. This pathway may present a novel target for combination therapy. PMID:23516582

  7. The Global Regulatory hns Gene Negatively Affects Adhesion to Solid Surfaces by Anaerobically Grown Escherichia coli by Modulating Expression of Flagellar Genes and Lipopolysaccharide Production

    PubMed Central

    Landini, Paolo; Zehnder, Alexander J. B.

    2002-01-01

    The initial binding of bacterial cells to a solid surface is a critical and essential step in biofilm formation. In this report we show that stationary-phase cultures of Escherichia coli W3100 (a K-12 strain) can efficiently attach to sand columns when they are grown in Luria broth medium at 28°C in fully aerobic conditions. In contrast, growth in oxygen-limited conditions results in a sharp decrease in adhesion to hydrophilic substrates. We show that the production of lipopolysaccharide (LPS) and of flagella, as well as the transcription of the fliC gene, encoding the major flagellar subunit, increases under oxygen-limited conditions. Inactivation of the global regulatory hns gene counteracts increased production of LPS and flagella in response to anoxia and allows E. coli W3100 to attach to sand columns even when it is grown under oxygen-limited conditions. We propose that increased production of the FliC protein and of LPS in response to oxygen limitation results in the loss of the ability of E. coli W3100 to adhere to hydrophilic surfaces. Indeed, overexpression of the fliC gene results in a decreased adhesion to sand even when W3100 is grown in fully aerobic conditions. Our observations strongly suggest that anoxia is a negative environmental signal for adhesion in E. coli. PMID:11872702

  8. Does vector-free gravity simulate microgravity? Functional and morphologic attributes of clinorotated nerve and muscle grown in cell culture

    NASA Technical Reports Server (NTRS)

    Gruener, Raphael; Hoeger, Glenn

    1988-01-01

    Cocultured Xenopus neurons and myocytes were subjected to nonvectorial gravity by clinostat rotation to determine the effects of microgravity on cell development and communications. Observed effects included increases in the myocyte and its nuclear area, fragmentation of nucleoli, the appearance of neuritic aneurysms, decreased growth in the presence of trophic factors, and decreased yolk utilization. These effects were most notable at 1-10 rpm and depended on the onset and duration of rotation. It is found that, in microgravity, cell differentiation is altered by interference with cytoskeleton-related mechanisms. It is suggested that the alteration of the distribution of acetylcholine receptor aggregates on myocytes which occurs might indicate that microgravity affects brain development.

  9. Effects of green-synthesized silver nanoparticles on lung cancer cells in vitro and grown as xenograft tumors in vivo

    PubMed Central

    He, Yan; Du, Zhiyun; Ma, Shijing; Liu, Yue; Li, Dongli; Huang, Huarong; Jiang, Sen; Cheng, Shupeng; Wu, Wenjing; Zhang, Kun; Zheng, Xi

    2016-01-01

    Silver nanoparticles (AgNPs) have now been recognized as promising therapeutic molecules and are extending their use in cancer diagnosis and therapy. This study demonstrates for the first time the antitumor activity of green-synthesized AgNPs against lung cancer in vitro and in vivo. Cytotoxicity effect was explored on human lung cancer H1299 cells in vitro by MTT and trypan blue assays. Apoptosis was measured by morphological assessment, and nuclear factor-κB (NF-κB) transcriptional activity was determined by a luciferase reporter gene assay. The expressions of phosphorylated stat3, bcl-2, survivin, and caspase-3 were examined by Western blot analysis. AgNPs showed dose-dependent cytotoxicity and stimulation of apoptosis in H1299 cells. The effects on H1299 cells correlated well with the inhibition of NF-κB activity, a decrease in bcl-2, and an increase in caspase-3 and survivin expression. AgNPs significantly suppressed the H1299 tumor growth in a xenograft severe combined immunodeficient (SCID) mouse model. The results demonstrate the anticancer activities of AgNPs, suggesting that they may act as potential beneficial molecules in lung cancer chemoprevention and chemotherapy, especially for early-stage intervention. PMID:27217750

  10. Aquaporin functionality in relation to H+-ATPase activity in root cells of Capsicum annuum grown under salinity.

    PubMed

    Martínez-Ballesta, M. Carmen; Martínez, Vicente; Carvajal, Micaela

    2003-03-01

    As water and nutrient uptake should be related in the response of plants to salinity, the aim of this paper is to establish whether or not aquaporin functionality is related to H+-ATPase activity in root cells of pepper (Capsicum annuum L.) plants. Thus, H+-ATPase activity was measured in plasma membrane vesicles isolated from roots and aquaporin functionality was measured using a cell pressure probe in intact roots. Salinity was applied as 60 mM NaCl or 60 mM KCl, to determine which ion (Na+, K+ or Cl-) is producing the effects. We also investigated whether the effects of both salts were ameliorated by Ca2+. Similar results were obtained for cell hydraulic conductivity, Lpc, and H+-ATPase activity, large reductions in the presence at NaCl or KCl and an ameliorative effect of Ca2+. However, fusicoccin (an activator of H+-ATPase) did not alter osmotic water permeability of protoplasts isolated from roots. Addition of Hg2+ inhibited both ATPase and aquaporins, but ATPase also contains Hg-binding sites. Therefore, the results indicate that H+-ATPase and aquaporin activities may not be related in pepper plants.

  11. Pim-2 Modulates Aerobic Glycolysis and Energy Production during the Development of Colorectal Tumors.

    PubMed

    Zhang, Xue-hui; Yu, Hong-liang; Wang, Fu-jing; Han, Yong-long; Yang, Wei-liang

    2015-01-01

    Tumor cells have higher rates of glucose uptake and aerobic glycolysis to meet energy demands for proliferation and metastasis. The characteristics of increased glucose uptake, accompanied with aerobic glycolysis, has been exploited for the diagnosis of cancers. Although much progress has been made, the mechanisms regulating tumor aerobic glycolysis and energy production are still not fully understood. Here, we demonstrate that Pim-2 is required for glycolysis and energy production in colorectal tumor cells. Our results show that Pim-2 is highly expressed in colorectal tumor cells, and may be induced by nutrient stimulation. Activation of Pim-2 in colorectal cells led to increase glucose utilization and aerobic glycolysis, as well as energy production. While knockdown of Pim-2 decreased energy production in colorectal tumor cells and increased their susceptibility to apoptosis. Moreover, the effects of Pim-2 kinase on aerobic glycolysis seem to be partly dependent on mTORC1 signaling, because inhibition of mTORC1 activity reversed the aerobic glycolysis mediated by Pim-2. Our findings suggest that Pim-2-mediated aerobic glycolysis is critical for monitoring Warburg effect in colorectal tumor cells, highlighting Pim-2 as a potential metabolic target for colorectal tumor therapy.

  12. The Transition from Aerobic to Anaerobic Metabolism.

    ERIC Educational Resources Information Center

    Skinner, James S.; McLellan, Thomas H.

    1980-01-01

    The transition from aerobic to anaerobic metabolism is discussed. More research is needed on different kinds of athletes and athletic activities and how they may affect aerobic and anaerobic metabolisms. (CJ)

  13. Effect of pH, aeration and sucrose feeding on the invertase activity of intact S. cerevisiae cells grown in sugarcane blackstrap molasses.

    PubMed

    Vitolo, M; Duranti, M A; Pellegrim, M B

    1995-08-01

    S. cerevisiae was grown in a blackstrap molasses containing medium in batch and fed-batch cultures. The following parameters were varied: pH (from 4.0 to 6.5), dissolved oxygen (DO) (from 0 to 5.0 mg O2 L-1) and sucrose feeding rate. When glucose concentration (S) was higher than 0.5 g L-1 a reduction in the specific invertase activity of intact cells (v) and an oscillatory behavior of v values during fermentation were observed. Both the invertase reduction and the oscillatory behavior of v values could be related to the glucose inhibitory effect on invertase biosynthesis. The best culture conditions for attaining S. cerevisiae cells suitable for invertase production were: temperature = 30 degrees C; pH = 5.0; DO = 3.3 mg O2 L-1; (S) = 0.5 g L-1 and sucrose added into the fermenter according to the equations: (V-Vo) = t2/16 or (V - Vo) = (Vf - Vo).(e0.6t-1)/10.

  14. Symbiodinium transcriptome and global responses of cells to immediate changes in light intensity when grown under autotrophic or mixotrophic conditions.

    PubMed

    Xiang, Tingting; Nelson, William; Rodriguez, Jesse; Tolleter, Dimitri; Grossman, Arthur R

    2015-04-01

    Symbiosis between unicellular dinoflagellates (genus Symbiodinium) and their cnidarian hosts (e.g. corals, sea anemones) is the foundation of coral reef ecosystems. Dysfunction of this symbiosis under changing environmental conditions has led to global reef decline. Little information is known about Symbiodinium gene expression and mechanisms by which light impacts host-symbiont associations. To address these issues, we generated a transcriptome from axenic Symbiodinium strain SSB01. Here we report features of the transcriptome, including occurrence and length distribution of spliced leader sequences, the functional landscape of encoded proteins and the impact of light on gene expression. Expression of many Symbiodinium genes appears to be significantly impacted by light. Transcript encoding cryptochrome 2 declined in high light while some transcripts for Regulators of Chromatin Condensation (RCC1) declined in the dark. We also identified a transcript encoding a light harvesting AcpPC protein with homology to Chlamydomonas LHCSR2. The level of this transcript increased in high light autotrophic conditions, suggesting that it is involved in photo-protection and the dissipation of excess absorbed light energy. The most extensive changes in transcript abundances occurred when the algae were transferred from low light to darkness. Interestingly, transcripts encoding several cell adhesion proteins rapidly declined following movement of cultures to the dark, which correlated with a dramatic change in cell surface morphology, likely reflecting the complexity of the extracellular matrix. Thus, light-sensitive cell adhesion proteins may play a role in establishing surface architecture, which may in turn alter interactions between the endosymbiont and its host.

  15. Electrochemical communication between heterotrophically grown Rhodobacter capsulatus with electrodes mediated by an osmium redox polymer.

    PubMed

    Hasan, Kamrul; Patil, Sunil A; Górecki, Kamil; Leech, Dónal; Hägerhäll, Cecilia; Gorton, Lo

    2013-10-01

    The metabolically versatile purple bacteria Rhodobacter capsulatus was investigated to check its possible applicability in biofuel cells and electrochemical microbial biosensors. The wild type strain ATCC 17015 and mutant strain 37b4 lacking the lipopolysaccharide capsule was compared for their ability to communicate with electrodes modified with an osmium redox polymer. In this work, aerobic heterotrophically grown R. capsulatus were used to screen for efficient cell-electrode communication for later implementation using photoheterotrophically grown bacteria. The bacterial cells embedded in the osmium polymer matrix demonstrated efficient electrical "wiring" with the electrodes and were able to generate a noticeable current with succinate as substrate. Interestingly, at 2mM succinate the wild type strain showed much better bioelectrocatalytic current generation (4.25 μA/cm(2)) than the strain lacking capsule (1.55 μA/cm(2)). The wild type strain also exhibited a stable current response for longer time, demonstrating that the bacterial lipopolysaccharide in fact enhances the stability of the polymer matrix layer of the modified electrode. Control experiments with R. capsulatus without any mediator did not show any current irrespective of the capsule presence. This demonstrates that development of photosensors and other light driven bioelectrochemical devices could be feasible using R. capsulatus and will be at focus for future studies.

  16. GaInP/GaAs tandem solar cells with highly Te- and Mg-doped GaAs tunnel junctions grown by MBE

    NASA Astrophysics Data System (ADS)

    Zheng, Xin-He; Liu, San-Jie; Xia, Yu; Gan, Xing-Yuan; Wang, Hai-Xiao; Wang, Nai-Ming; Yang, Hui

    2015-10-01

    We report a GaInP/GaAs tandem solar cell with a novel GaAs tunnel junction (TJ) with using tellurium (Te) and magnesium (Mg) as n- and p-type dopants via dual-filament low temperature effusion cells grown by molecular beam epitaxy (MBE) at low temperature. The test Te/Mg-doped GaAs TJ shows a peak current density of 21 A/cm2. The tandem solar cell by the Te/Mg TJ shows a short-circuit current density of 12 mA/cm2, but a low open-circuit voltage range of 1.4 V˜1.71 V under AM1.5 illumination. The secondary ion mass spectroscopy (SIMS) analysis reveals that the Te doping is unexpectedly high and its doping profile extends to the Mg doping region, thus possibly resulting in a less abrupt junction with no tunneling carriers effectively. Furthermore, the tunneling interface shifts from the intended GaAs n++/p++ junction to the AlGaInP/GaAs junction with a higher bandgap AlGaInP tunneling layers, thereby reducing the tunneling peak. The Te concentration of ˜ 2.5 × 1020 in GaAs could cause a lattice strain of 10-3 in magnitude and thus a surface roughening, which also negatively influences the subsequent growth of the top subcell and the GaAs contacting layers. The doping features of Te and Mg are discussed to understand the photovoltaic response of the studied tandem cell. Project supported by the SINANO-SONY Joint Program (Grant No. Y1AAQ11001), the National Natural Science Foundation of China (Grant No. 61274134), the USCB Start-up Program (Grant No. 06105033), and the International Cooperation Projects of Suzhou City, China (Grant No. SH201215).

  17. Adenosine accelerates the healing of diabetic ischemic ulcers by improving autophagy of endothelial progenitor cells grown on a biomaterial

    PubMed Central

    Chen, Wen; Wu, Yangxiao; Li, Li; Yang, Mingcan; Shen, Lei; Liu, Ge; Tan, Ju; Zeng, Wen; Zhu, Chuhong

    2015-01-01

    Endothelial progenitor cells (EPCs) seeded on biomaterials can effectively promote diabetic ischemic wound healing. However, the function of transplanted EPCs is negatively affected by a high-glucose and ischemic microenvironment. Our experiments showed that EPC autophagy was inhibited and mitochondrial membrane potential (MMP) was increased in diabetic patients, while adenosine treatment decreased the energy requirements and increased the autophagy levels of EPCs. In animal experiments, we transplanted a biomaterial seeded with EPCs onto the surface of diabetic wounds and found that adenosine-stimulated EPCs effectively promoted wound healing. Increased microvascular genesis and survival of the transplanted cells were also observed in the adenosine-stimulated groups. Interestingly, our study showed that adenosine increased the autophagy of the transplanted EPCs seeded onto the biomaterial and maintained EPC survival at 48 and 96 hours. Moreover, we observed that adenosine induced EPC differentiation through increasing the level of autophagy. In conclusion, our study indicated that adenosine-stimulated EPCs seeded onto a biomaterial significantly improved wound healing in diabetic mice; mechanistically, adenosine might maintain EPC survival and differentiation by increasing high glucose-inhibited EPC autophagy and maintaining cellular energy metabolism. PMID:26108983

  18. Multi-stacked InAs/GaAs quantum dots grown with different growth modes for quantum dot solar cells

    NASA Astrophysics Data System (ADS)

    Kim, Yeongho; Ban, Keun-Yong; Honsberg, Christiana B.

    2015-06-01

    We have studied the material properties and device performance of InAs/GaAs quantum dot solar cells (QDSCs) made using three different QD growth modes: Stranski-Krastanov (S-K), quasi-monolayer (QML), and sub-monolayer (SML) growth modes. All QDSCs show an extended external quantum efficiency (EQE) at near infrared wavelengths of 950-1070 nm from the QD absorption. Compared to the S-K and SML QDSCs, the QML QDSC with a higher strain exhibits a poor EQE response in the wavelength region of 300-880 nm due to increased non-radiative recombination. The conversion efficiency of the S-K and SML QDSCs exceeds that of the reference cell (13.4%) without QDs due to an enhanced photocurrent (>16% increase) produced by the silicon doped QD stacks. However, as expected from the EQE of the QML QDSC, the increase of strain-induced crystalline defects greatly degrades the photocurrent and open-circuit voltage, leading to the lowest conversion efficiency (8.9%).

  19. Multi-stacked InAs/GaAs quantum dots grown with different growth modes for quantum dot solar cells

    SciTech Connect

    Kim, Yeongho; Ban, Keun-Yong Honsberg, Christiana B.

    2015-06-01

    We have studied the material properties and device performance of InAs/GaAs quantum dot solar cells (QDSCs) made using three different QD growth modes: Stranski-Krastanov (S-K), quasi-monolayer (QML), and sub-monolayer (SML) growth modes. All QDSCs show an extended external quantum efficiency (EQE) at near infrared wavelengths of 950–1070 nm from the QD absorption. Compared to the S-K and SML QDSCs, the QML QDSC with a higher strain exhibits a poor EQE response in the wavelength region of 300–880 nm due to increased non-radiative recombination. The conversion efficiency of the S-K and SML QDSCs exceeds that of the reference cell (13.4%) without QDs due to an enhanced photocurrent (>16% increase) produced by the silicon doped QD stacks. However, as expected from the EQE of the QML QDSC, the increase of strain-induced crystalline defects greatly degrades the photocurrent and open-circuit voltage, leading to the lowest conversion efficiency (8.9%)

  20. Sb2S3 grown by ultrasonic spray pyrolysis and its application in a hybrid solar cell

    PubMed Central

    Katerski, Atanas; Oja Acik, Ilona; Mere, Arvo; Mikli, Valdek; Krunks, Malle

    2016-01-01

    Chemical spray pyrolysis (CSP) is a fast wet-chemical deposition method in which an aerosol is guided by carrier gas onto a hot substrate where the decomposition of the precursor chemicals occurs. The aerosol is produced using an ultrasonic oscillator in a bath of precursor solution and guided by compressed air. The use of the ultrasonic CSP resulted in the growth of homogeneous and well-adhered layers that consist of submicron crystals of single-phase Sb2S3 with a bandgap of 1.6 eV if an abundance of sulfur source is present in the precursor solution (SbCl3/SC(NH2)2 = 1:6) sprayed onto the substrate at 250 °C in air. Solar cells with glass-ITO-TiO2-Sb2S3-P3HT-Au structure and an active area of 1 cm2 had an open circuit voltage of 630 mV, short circuit current density of 5 mA/cm2, a fill factor of 42% and a conversion efficiency of 1.3%. Conversion efficiencies up to 1.9% were obtained from solar cells with smaller areas. PMID:28144515

  1. Sb2S3 grown by ultrasonic spray pyrolysis and its application in a hybrid solar cell.

    PubMed

    Kärber, Erki; Katerski, Atanas; Oja Acik, Ilona; Mere, Arvo; Mikli, Valdek; Krunks, Malle

    2016-01-01

    Chemical spray pyrolysis (CSP) is a fast wet-chemical deposition method in which an aerosol is guided by carrier gas onto a hot substrate where the decomposition of the precursor chemicals occurs. The aerosol is produced using an ultrasonic oscillator in a bath of precursor solution and guided by compressed air. The use of the ultrasonic CSP resulted in the growth of homogeneous and well-adhered layers that consist of submicron crystals of single-phase Sb2S3 with a bandgap of 1.6 eV if an abundance of sulfur source is present in the precursor solution (SbCl3/SC(NH2)2 = 1:6) sprayed onto the substrate at 250 °C in air. Solar cells with glass-ITO-TiO2-Sb2S3-P3HT-Au structure and an active area of 1 cm(2) had an open circuit voltage of 630 mV, short circuit current density of 5 mA/cm(2), a fill factor of 42% and a conversion efficiency of 1.3%. Conversion efficiencies up to 1.9% were obtained from solar cells with smaller areas.

  2. Virulence factors enhance Citrobacter rodentium expansion through aerobic respiration.

    PubMed

    Lopez, Christopher A; Miller, Brittany M; Rivera-Chávez, Fabian; Velazquez, Eric M; Byndloss, Mariana X; Chávez-Arroyo, Alfredo; Lokken, Kristen L; Tsolis, Renée M; Winter, Sebastian E; Bäumler, Andreas J

    2016-09-16

    Citrobacter rodentium uses a type III secretion system (T3SS) to induce colonic crypt hyperplasia in mice, thereby gaining an edge during its competition with the gut microbiota through an unknown mechanism. Here, we show that by triggering colonic crypt hyperplasia, the C. rodentium T3SS induced an excessive expansion of undifferentiated Ki67-positive epithelial cells, which increased oxygenation of the mucosal surface and drove an aerobic C. rodentium expansion in the colon. Treatment of mice with the γ-secretase inhibitor dibenzazepine to diminish Notch-driven colonic crypt hyperplasia curtailed the fitness advantage conferred by aerobic respiration during C. rodentium infection. We conclude that C. rodentium uses its T3SS to induce histopathological lesions that generate an intestinal microenvironment in which growth of the pathogen is fueled by aerobic respiration.

  3. Virulence factors enhance Citrobacter rodentium expansion through aerobic respiration

    PubMed Central

    Lopez, Christopher A.; Miller, Brittany M.; Rivera-Chávez, Fabian; Velazquez, Eric; Byndloss, Mariana X.; Chávez-Arroyo, Alfredo; Lokken, Kristen L.; Tsolis, Renée M.; Winter, Sebastian E.; Bäumler, Andreas J.

    2016-01-01

    Citrobacter rodentium uses a type III secretion system (T3SS) to induce colonic crypt hyperplasia in mice, thereby gaining an edge during its competition with the gut microbiota through an unknown mechanism. Here we show that by triggering colonic crypt hyperplasia, the C. rodentium T3SS induced an excessive expansion of undifferentiated Ki67-positive epithelial cells, which increased oxygenation of the mucosal surface and drove an aerobic C. rodentium expansion in the colon. Treatment of mice with the γ-secretase inhibitor dibenzazepine to diminish Notch-driven colonic crypt hyperplasia curtailed the fitness advantage conferred by aerobic respiration during C. rodentium infection. We conclude that C. rodentium uses its T3SS to induce histopathological lesions that generate an intestinal microenvironment in which growth of the pathogen is fueled by aerobic respiration. PMID:27634526

  4. Arthritis and Aerobic Exercise: A Review.

    ERIC Educational Resources Information Center

    Ike, Robert W.; And Others

    1989-01-01

    Arthritic patients who regularly do aerobic exercise make significant gains in aerobic and functional status, and in subjective areas like pain tolerance and mood. Still, they are often advised to curtail physical activity. Guidelines are presented for physicians prescribing aerobic exercise. An exercise tolerance test is recommended. (SM)

  5. Biotransformation of phytosterols under aerobic conditions.

    PubMed

    Dykstra, Christy M; Giles, Hamilton D; Banerjee, Sujit; Pavlostathis, Spyros G

    2014-07-01

    Phytosterols are plant-derived sterols present in pulp and paper wastewater and have been implicated in the endocrine disruption of aquatic species. Bioassays were performed to assess the effect of an additional carbon source and/or solubilizing agent on the aerobic biotransformation of a mixture of three common phytosterols (β-sitosterol, stigmasterol and campesterol). The aerobic biotransformation of the phytosterol mixture by a mixed culture developed from a pulp and paper wastewater treatment system was examined under three separate conditions: with phytosterols as the sole added carbon source, with phytosterols and dextrin as an additional carbon source, and with phytosterols added with ethanol as an additional carbon source and solubilizing agent. Significant phytosterol removal was not observed in assays set up with phytosterol powder, either with or without an additional carbon source. In contrast, all three phytosterols were aerobically degraded when added as a dissolved solution in ethanol. Thus, under the experimental conditions of this study, the bioavailability of phytosterols was limited without the presence of a solubilizing agent. The total phytosterol removal rate was linear for the first six days before re-spiking, with a rate of 0.47 mg/L-d (R(2) = 0.998). After the second spiking, the total phytosterol removal rate was linear for seven days, with a rate of 0.32 mg/L-d (R(2) = 0.968). Following the 7th day, the phytosterol removal rate markedly accelerated, suggesting two different mechanisms are involved in phytosterol biotransformation, more likely related to the production of enzyme(s) involved in phytosterol degradation, induced under different cell growth conditions. β-sitosterol was preferentially degraded, as compared to stigmasterol and campesterol, although all three phytosterols fell below detection limits by the 24th day of incubation.

  6. Solar cells on low-resistivity boron-doped Czochralski-grown silicon with stabilized efficiencies of 20%

    NASA Astrophysics Data System (ADS)

    Lim, Bianca; Hermann, Sonja; Bothe, Karsten; Schmidt, Jan; Brendel, Rolf

    2008-10-01

    Recently, it was shown that the boron-oxygen complex responsible for the light-induced lifetime degradation in oxygen-rich boron-doped silicon can be permanently deactivated by illumination at elevated temperatures. Since the degradation is particularly harmful in low-resistivity Czochralski silicon (Cz-Si), we apply the deactivation procedure to a high-efficiency rear interdigitated single evaporation emitter wrap-through solar cell made on 1.4Ωcm B-doped Cz-Si. The energy conversion efficiency is thereby increased by more than 1% absolute compared to the degraded state to 20.3% on a designated area of 92cm2 and is furthermore shown to be stable under illumination at room temperature.

  7. Evaluation of defects generation in crystalline silicon ingot grown by cast technique with seed crystal for solar cells

    PubMed Central

    Tachibana, Tomihisa; Sameshima, Takashi; Kojima, Takuto; Arafune, Koji; Kakimoto, Koichi; Miyamura, Yoshiji; Harada, Hirofumi; Sekiguchi, Takashi; Ohshita, Yoshio; Ogura, Atsushi

    2012-01-01

    Although crystalline silicon is widely used as substrate material for solar cell, many defects occur during crystal growth. In this study, the generation of crystalline defects in silicon substrates was evaluated. The distributions of small-angle grain boundaries were observed in substrates sliced parallel to the growth direction. Many precipitates consisting of light elemental impurities and small-angle grain boundaries were confirmed to propagate. The precipitates mainly consisted of Si, C, and N atoms. The small-angle grain boundaries were distributed after the precipitation density increased. Then, precipitates appeared at the small-angle grain boundaries. We consider that the origin of the small-angle grain boundaries was lattice mismatch and/or strain caused by the high-density precipitation. PMID:22536006

  8. Carrier dynamics in QW and bulk bismide and epitaxial lift off GaAs-In(Al)GaP double heterostructures grown by MOVPE for multi-junction solar cells

    NASA Astrophysics Data System (ADS)

    Sin, Yongkun; Peterson, Mark; Lingley, Zachary; LaLumondiere, Stephen; Moss, Steven C.; Kim, Honghyuk; Forghani, Kamran; Guan, Yingxin; Kim, Kangho; Lee, Jaejin; Mawst, Luke J.; Kuech, Thomas F.; Tatavarti, Rao

    2016-03-01

    III-V multi-junction solar cells are based on a triple-junction design that consists of an InGaP top junction, a GaAs middle junction, and a bottom junction that employs either a 1eV material grown on the GaAs substrate or InGaAs grown on the Ge substrate. The most promising 1 eV materials under extensive investigation are the bulk dilute nitride such as InGaAsN(Sb) lattice-matched to GaAs substrate and the dilute-bismide quantum well materials, such as GaAsBi, strain-compensated with GaAsP barriers. Both approaches have the potential to achieve high performance triple-junction solar cells. In addition, space satellite applications utilizing III-V triple-junction solar cells can have significantly reduced weight and high efficiency. An attractive approach to achieve these goals is to employ full-wafer epitaxial lift off (ELO) technology, which can eliminate the substrate weight and also enable multiple substrate re-usages. For the present study, we employed time-resolved photoluminescence (TR-PL) techniques to study carrier dynamics in MOVPE-grown bulk dilute bismide double heterostructures (DH). Carrier lifetime measurements are crucial to optimizing MOVPE materials growth. We have studied carrier dynamics in GaAsBi QW structures with GaAsP barriers. Carrier lifetimes were measured from GaAsBi DH samples at different stages of post-growth thermal annealing steps. Post-growth annealing yielded significant improvements in carrier lifetimes. Based on this study, single junction solar cells (SJSC) were grown and annealed under a variety of conditions and characterized. The SJSC annealed at 600 - 650 °C exhibited improved response in EQE spectra. In addition, we studied carrier dynamics in MOVPE-grown GaAs-In(Al)GaP DH samples grown on GaAs substrates. The structures were grown on top of a thin AlAs release layer, which allowed epitaxial layers grown on top of the AlAs layer to be removed from the substrate. The GaAs active layers had various doping densities and

  9. [Isolation and identification of electrochemically active microorganism from micro-aerobic environment].

    PubMed

    Wu, Song; Xiao, Yong; Zheng, Zhi-Yong; Zheng, Yue; Yang, Zhao-Hui; Zhao, Feng

    2014-10-01

    Extracellular electron transfer of electrochemically active microorganism plays vital role in biogeochemical cycling of metals and carbon and in biosynthesis of bioenergy. Compared to anaerobic anode, micro-aerobic anode captures more energy from microbial fuel cell. However, most of previous researches focused on functioning bacteria in anaerobic anode, functioning bacteria in micro-aerobic anode was rarely studied. Herein, we used the traditional aerobic screening technology to isolate functioning bacteria from a micro-aerobic anode. Three pure cultures Aeromonas sp. WS-XY2, Citrobacter sp. WS-XY3 and Bacterium strain WS-XY4 were obtained. WS-XY2 and WS-XY3 were belonged to Proteobacteria, whereas WS-XY4 was possibly a new species. Cyclic voltammetry and chronoamperometry analysis demonstrated all of them showed the electrochemical activity by direct extracellular electron transfer, and micro-aerobic anode could select bacteria that have similar electrochemical activity to proliferate on the anode. We further conclude that functioning bacteria in micro-aerobic anode are more efficient than that of anaerobic anode may be the reason that micro-aerobic anode has better performance than anaerobic anode. Therefore, a thorough study of functioning bacteria in micro-aerobic anode will significantly promote the energy recovery from microbial fuel cell.

  10. Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor

    NASA Technical Reports Server (NTRS)

    Chapatwala, Kirit D.; Babu, G. R. V.; Baresi, Larry; Trunzo, Richard M.

    1995-01-01

    Bacteria capable of degrading trichloroethylene (TCE) were isolated from contaminated wastewaters and soil sites. The aerobic cultures were identified as Pseudomonas aeruginosa (four species) and Pseudomonas fluorescens. The optimal conditions for the growth of aerobic cultures were determined. The minimal inhibitory concentration values of TCE for Pseudomonas sps. were also determined. The aerobic cells were immobilized in calcium alginate in the form of beads. Degradation of TCE by the anaerobic and dichloroethylene (DCE) by aerobic cultures was studied using dual reactors - anaerobic biofilm and aerobic immobilized bed reactor. The minimal mineral salt (MMS) medium saturated with TCE was pumped at the rate of 1 ml per hour into the anaerobic reactor. The MMS medium saturated with DCE and supplemented with xylenes and toluene (3 ppm each) was pumped at the rate of 1 ml per hour into the fluidized air-uplift-type reactor containing the immobilized aerobic cells. The concentrations of TCE and DCE and the metabolites formed during their degradation by the anaerobic and aerobic cultures were monitored by GC. The preliminary study suggests that the anaerobic and aerobic cultures of our isolates can degrade TCE and DCE.

  11. Regulation of Cell Division, Biofilm Formation, and Virulence by FlhC in Escherichia coli O157:H7 Grown on Meat▿†

    PubMed Central

    Sule, Preeti; Horne, Shelley M.; Logue, Catherine M.; Prüß, Birgit M.

    2011-01-01

    To understand the continuous problems that Escherichia coli O157:H7 causes as food pathogen, this study assessed global gene regulation in bacteria growing on meat. Since FlhD/FlhC of E. coli K-12 laboratory strains was previously established as a major control point in transducing signals from the environment to several cellular processes, this study compared the expression pattern of an E. coli O157:H7 parent strain to that of its isogenic flhC mutant. This was done with bacteria that had been grown on meat. Microarray experiments revealed 287 putative targets of FlhC. Real-time PCR was performed as an alternative estimate of transcription and confirmed microarray data for 13 out of 15 genes tested (87%). The confirmed genes are representative of cellular functions, such as central metabolism, cell division, biofilm formation, and pathogenicity. An additional 13 genes from the same cellular functions that had not been hypothesized as being regulated by FlhC by the microarray experiment were tested with real-time PCR and also exhibited higher expression levels in the flhC mutant than in the parent strain. Physiological experiments were performed and confirmed that FlhC reduced the cell division rate, the amount of biofilm biomass, and pathogenicity in a chicken embryo lethality model. Altogether, this study provides valuable insight into the complex regulatory network of the pathogen that enables its survival under various environmental conditions. This information may be used to develop strategies that could be used to reduce the number of cells or pathogenicity of E. coli O157:H7 on meat by interfering with the signal transduction pathways. PMID:21498760

  12. InGaAs/GaAsP strain balanced multi-quantum wires grown on misoriented GaAs substrates for high efficiency solar cells

    NASA Astrophysics Data System (ADS)

    Alonso-Álvarez, D.; Thomas, T.; Führer, M.; Hylton, N. P.; Ekins-Daukes, N. J.; Lackner, D.; Philipps, S. P.; Bett, A. W.; Sodabanlu, H.; Fujii, H.; Watanabe, K.; Sugiyama, M.; Nasi, L.; Campanini, M.

    2014-08-01

    Quantum wires (QWRs) form naturally when growing strain balanced InGaAs/GaAsP multi-quantum wells (MQW) on GaAs [100] 6° misoriented substrates under the usual growth conditions. The presence of wires instead of wells could have several unexpected consequences for the performance of the MQW solar cells, both positive and negative, that need to be assessed to achieve high conversion efficiencies. In this letter, we study QWR properties from the point of view of their performance as solar cells by means of transmission electron microscopy, time resolved photoluminescence and external quantum efficiency (EQE) using polarised light. We find that these QWRs have longer lifetimes than nominally identical QWs grown on exact [100] GaAs substrates, of up to 1 μs, at any level of illumination. We attribute this effect to an asymmetric carrier escape from the nanostructures leading to a strong 1D-photo-charging, keeping electrons confined along the wire and holes in the barriers. In principle, these extended lifetimes could be exploited to enhance carrier collection and reduce dark current losses. Light absorption by these QWRs is 1.6 times weaker than QWs, as revealed by EQE measurements, which emphasises the need for more layers of nanostructures or the use light trapping techniques. Contrary to what we expected, QWR show very low absorption anisotropy, only 3.5%, which was the main drawback a priori of this nanostructure. We attribute this to a reduced lateral confinement inside the wires. These results encourage further study and optimization of QWRs for high efficiency solar cells.

  13. Inhibition of vimentin or B1 integrin reverts morphology of prostate tumor cells grown in laminin-rich extracellular matrix gels and reduces tumor growth in vivo

    SciTech Connect

    Zhang, Xueping; Fournier, Marcia V; Ware, Joy L; Bissell, Mina J; Yacoub, Adly; Zehner, Zendra E

    2008-06-12

    Prostate epithelial cells grown embedded in laminin-rich extracellular matrix (lrECM) undergo morphologic changes that closely resemble their architecture in vivo. In this study, growth characteristics of three human prostate epithelial sublines derived from the same cellular lineage, but displaying different tumorigenic and metastatic properties in vivo, were assessed in three-dimensional lrECM gels. M12, a highly tumorigenic and metastatic subline, was derived from the immortalized, prostate epithelial P69 cell line by selection in athymic, nude mice and found to contain a deletion of 19p-q13.1. The stable reintroduction of an intact human chromosome 19 into M12 resulted in a poorly tumorigenic subline, designated F6. When embedded in lrECM gels, the parental, nontumorigenic P69 line produced acini with clearly defined lumena. Immunostaining with antibodies to {beta}-catenin, E-cadherin, or {alpha}6 and {beta}1 integrins showed polarization typical of glandular epithelium. In contrast, the metastatic M12 subline produced highly disorganized cells with no evidence of polarization. The F6 subline reverted to acini-like structures exhibiting basal polarity marked with integrins. Reducing either vimentin levels via small interfering RNA interference or the expression of {alpha}6 and {beta}1 integrins by the addition of blocking antibodies, reorganized the M12 subline into forming polarized acini. The loss of vimentin significantly reduced M12-Vim tumor growth when assessed by s.c. injection in athymic mice. Thus, tumorigenicity in vivo correlated with disorganized growth in three-dimensional lrECM gels. These studies suggest that the levels of vimentin and {beta}1 integrin play a key role in the homeostasis of the normal acinus in prostate and that their dysregulation may lead to tumorigenesis. [Mol Cancer Ther 2009;8(3):499-508].

  14. Crystal Engineering for Low Defect Density and High Efficiency Hybrid Chemical Vapor Deposition Grown Perovskite Solar Cells.

    PubMed

    Ng, Annie; Ren, Zhiwei; Shen, Qian; Cheung, Sin Hang; Gokkaya, Huseyin Cem; So, Shu Kong; Djurišić, Aleksandra B; Wan, Yangyang; Wu, Xiaojun; Surya, Charles

    2016-12-07

    Synthesis of high quality perovskite absorber is a key factor in determining the performance of the solar cells. We demonstrate that hybrid chemical vapor deposition (HCVD) growth technique can provide high level of versatility and repeatability to ensure the optimal conditions for the growth of the perovskite films as well as potential for batch processing. It is found that the growth ambient and degree of crystallization of CH3NH3PbI3 (MAPI) have strong impact on the defect density of MAPI. We demonstrate that HCVD process with slow postdeposition cooling rate can significantly reduce the density of shallow and deep traps in the MAPI due to enhanced material crystallization, while a mixed O2/N2 carrier gas is effective in passivating both shallow and deep traps. By careful control of the perovskite growth process, a champion device with power conversion efficiency of 17.6% is achieved. Our work complements the existing theoretical studies on different types of trap states in MAPI and fills the gap on the theoretical analysis of the interaction between deep levels and oxygen. The experimental results are consistent with the theoretical predictions.

  15. Effect of linear alkylbenzene sulfonates on the growth of aerobic heterotrophic cultivable bacteria isolated from an agricultural soil.

    PubMed

    Sánchez-Peinado, María del Mar; González-López, Jesús; Rodelas, Belén; Galera, Vanesa; Pozo, Clementina; Martínez-Toledo, María Victoria

    2008-08-01

    An enrichment culture technique was used to isolate soil bacteria capable of growing in the presence of two different concentrations of linear alkylbenzene sulfonates (LAS) (10 and 500 microg ml(-1)). Nine bacterial strains, representatives of the major colony types of aerobic heterotrophic cultivable bacteria in the enriched samples, were isolated and subsequently identified by PCR-amplification and partial sequencing of the 16S rRNA gene. Amongst the isolates, strains LAS05 (Pseudomonas syringae), LAS06 (Staphylococcus epidermidis), LAS07 (Delftia tsuruhatensis), LAS08 (Staphylococcus epidermidis) and LAS09 (Enterobacter aerogenes), were able to grow in pure culture in dialysed soil media amended with LAS (50 microg ml(-1)). The three Gram-negative strains grew to higher cell numbers in the presence of 50 microg ml(-1) of LAS, compared to LAS-unamended dialysed soil medium, and were selected for further testing of their ability to use LAS as carbon source. However, HPLC analysis of culture supernatants showed that the three strains can tolerate but not degrade LAS when grown in pure cultures. A higher concentration of soluble phosphates was recorded in dialysed soil media amended with LAS (50 microg ml(-1)) compared to unamended control media, suggesting an effect of the surfactant that enhanced the bioavailability of P from soil. The presence of LAS at a concentration of 50 microg ml(-1) had an important impact on growth of selected aerobic heterotrophic soil bacteria, a deleterious effect which may be relevant for the normal function and evolution of agricultural soil.

  16. Aerobic Biodegradation of Trichloroethylene.

    DTIC Science & Technology

    1987-07-01

    the meta ring-fission product , the supernatant solution of phenol- induced restTW cells incubated with catechol and 3-methylcatechol was examined ...into C02 and unidentified nonvolatile products . Phenol, 41 toiin- andq-cresol were found to replace the site water requirement for TCE metabolism...undertaken in an effort to discover microorganisms capable of degrading TCE to innocuous products . Isolation of a microorganism with TCE-degrading ability

  17. Tumor vessel normalization after aerobic exercise enhances chemotherapeutic efficacy

    PubMed Central

    Schadler, Keri L.; Thomas, Nicholas J.; Galie, Peter A.; Bhang, Dong Ha; Roby, Kerry C.; Addai, Prince; Till, Jacob E.; Sturgeon, Kathleen; Zaslavsky, Alexander; Chen, Christopher S.; Ryeom, Sandra

    2016-01-01

    Targeted therapies aimed at tumor vasculature are utilized in combination with chemotherapy to improve drug delivery and efficacy after tumor vascular normalization. Tumor vessels are highly disorganized with disrupted blood flow impeding drug delivery to cancer cells. Although pharmacologic anti-angiogenic therapy can remodel and normalize tumor vessels, there is a limited window of efficacy and these drugs are associated with severe side effects necessitating alternatives for vascular normalization. Recently, moderate aerobic exercise has been shown to induce vascular normalization in mouse models. Here, we provide a mechanistic explanation for the tumor vascular normalization induced by exercise. Shear stress, the mechanical stimuli exerted on endothelial cells by blood flow, modulates vascular integrity. Increasing vascular shear stress through aerobic exercise can alter and remodel blood vessels in normal tissues. Our data in mouse models indicate that activation of calcineurin-NFAT-TSP1 signaling in endothelial cells plays a critical role in exercise-induced shear stress mediated tumor vessel remodeling. We show that moderate aerobic exercise with chemotherapy caused a significantly greater decrease in tumor growth than chemotherapy alone through improved chemotherapy delivery after tumor vascular normalization. Our work suggests that the vascular normalizing effects of aerobic exercise can be an effective chemotherapy adjuvant. PMID:27589843

  18. Interleukin-6 stimulates aerobic glycolysis by regulating PFKFB3 at early stage of colorectal cancer.

    PubMed

    Han, Jun; Meng, Qingyang; Xi, Qiulei; Zhang, Yongxian; Zhuang, Qiulin; Han, Yusong; Jiang, Yi; Ding, Qiurong; Wu, Guohao

    2016-01-01

    Chronic inflammation is a well-known etiological factor for colorectal cancer (CRC) and cancer cells are known to preferentially metabolize glucose through aerobic glycolysis. However, the connection between chronic inflammation and aerobic glycolysis in the development of CRC is largely unexplored. The present study investigated whether interleukin-6 (IL-6), a pro-inflammatory cytokine, promotes the development of CRC by regulating the aerobic glycolysis and the underlying molecular mechanisms. In colitis-associated CRC mouse, anti-IL-6 receptor antibody treatment reduced the incidence of CRC and decreased the expression of key genes in aerobic glycolysis, whereas the plasma concentrations of glucose and lactate were not affected. Consistently, IL-6 treatment stimulated aerobic glycolysis, upregulated key genes in aerobic glycolysis and promoted cell proliferation and migration in SW480 and SW1116 CRC cells. 6-phoshofructo-2-kinase/fructose-2,6-bisphosphatase-3 (PFKFB3) was the most downregulated gene by anti-IL-6 receptor antibody in colorectal adenoma tissues. Further analysis in human samples revealed overexpression of PFKFB3 in colorectal adenoma and adenocarcinoma tissues, which was also associated with lymph node metastasis, intravascular cancer embolus and TNM stage. In addition, the effect of IL-6 on CRC cells can be abolished by knocking down PRKFB3 through siRNA transfection. Our data suggest that chronic inflammation promotes the development of CRC by stimulating aerobic glycolysis and IL-6 is functioning, at least partly, through regulating PFKFB3 at early stage of CRC.

  19. P-H bonds in the surface unit cell of P-rich ordered InP(001) grown by metalorganic chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Letzig, T.; Schimper, H.-J.; Hannappel, T.; Willig, F.

    2005-01-01

    The Fourier transform infrared spectrum of the MOCVD-grown (metalorganic chemical vapor deposition) P-rich ordered InP(001) surface was measured in ultrahigh vacuum applying attenuated total reflection. The surface was measured without carrying out any post-transfer surface preparation. The low-energy electron defraction pattern showed the well-known (2×1) structure with streaks in the [-110] direction. After exposure to activated deuterium, the different infrared spectrum revealed a pronounced peak at 2308cm-1 , which was ascribed to P-H bonds. Polarization-dependent spectra showed the dipole moments of the P-H bonds oriented only in [001] and [-110] directions. A weak 0.8cm-1 splitting was measured between the symmetric and antisymmetric modes of two neighboring P-H bonds. These observations provide direct proof for two oriented P-H bonds as in the surface unit cell proposed by Hahn and Schmidt [Surf. Rev. Lett. 10, 163 (2003)]. Additional much smaller peaks with different polarization behavior varied greatly for different samples and were ascribed to defects or impurities.

  20. Nickel nanocrystals grown on sparse hierarchical CuS microflowers as high-performance counter electrodes for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Shi, Zhaoliang; Zhou, Wei; Ma, Yiran

    2016-07-01

    Three kinds of hierarchical CuS microflowers composed of thin nanosheets have been synthesized by a simple wet chemical method. It is shown that the CuS microflowers provide suitable substrates to grow nickel nanocrystals. The prepared Ni@CuS hybrids combined with conductive glass (FTO) have been used as counter electrodes for dye-sensitized solar cells (DSSCs). The electrode made of the active material of Ni@CuS microflowers with sparsest petals show an optimal photoelectric conversion efficiency of 4.89%, better than those made of single component of Ni (3.39%) or CuS (1.65%), and other two Ni@CuS composites. The improved performances could be ascribed to the synergetic effect of the catalytic effect towards I3-/I- from sparse CuS hierarchical structure and uniformly grown Ni nanocrystals. Besides, the introduced Ni nanocrystals could increase the conductivity of the hybrid and facilitate the transport of electrons. The hybrid Ni@CuS composites serving as counter electrodes have much enhanced electrochemical properties, which provide a feasible route to develop high-active non-noble hybrid counter electrode materials.

  1. Inactivation of the Kluyveromyces lactis KlPDA1 gene leads to loss of pyruvate dehydrogenase activity, impairs growth on glucose and triggers aerobic alcoholic fermentation.

    PubMed

    Zeeman, A M; Luttik, M A; Thiele, C; van Dijken, J P; Pronk, J T; Steensma, H Y

    1998-12-01

    The KlPDA1 gene, encoding the E1alpha subunit of the mitochondrial pyruvate-dehydrogenase (PDH) complex was isolated from a Kluyveromyces lactis genomic library by screening with a 1.1 kb internal fragment of the Saccharomyces cerevisiae PDA1 gene. The predicted amino acid sequence encoded by KlPDA1 showed 87% similarity and 79% identity to its S. cerevisiae counterpart. Disruption of KIPDA1 resulted in complete absence of PDH activity in cell extracts. The maximum specific growth rate on glucose of null mutants was 3.5-fold lower than that of the wild-type, whereas growth on ethanol was unaffected. Wild-type K. lactis CBS 2359 exhibits a Crabtree-negative phenotype, i.e. no ethanol was produced in aerobic batch cultures grown on glucose. In contrast, substantial amounts of ethanol and acetaldehyde were produced in aerobic cultures of an isogenic Klpda1 null mutant. A wild-type specific growth rate was restored after introduction of an intact KlPDA1 gene but not, as previously found for S. cerevisiae pda1 mutants, by cultivation in the presence of leucine. The occurrence of aerobic fermentation and slow growth of the Klpda1 null mutant indicate that, although present, the enzymes of the PDH bypass (pyruvate decarboxylase, acetaldehyde dehydrogenase and acetyl-CoA synthetase) could not efficiently replace the PDH complex during batch cultivation on glucose. Only at relatively low growth rates (D = 0.10 h(-1)) in aerobic, glucose-limited chemostat cultures, could the PDH bypass completely replace the PDH complex, thus allowing fully respiratory growth. This resulted in a lower biomass yield [g biomass (g glucose)-1] than in the wild-type due to a higher consumption of ATP in the PDH bypass compared to the formation of acetyl-CoA via the PDH complex.

  2. Video of Tissue Grown in Space in NASA Bioreactor

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Principal investigator Leland Chung grew prostate cancer and bone stromal cells aboard the Space Shuttle Columbia during the STS-107 mission. Although the experiment samples were lost along with the ill-fated spacecraft and crew, he did obtain downlinked video of the experiment that indicates the enormous potential of growing tissues in microgravity. Cells grown aboard Columbia had grown far larger tissue aggregates at day 5 than did the cells grown in a NASA bioreactor on the ground.

  3. Purification and Characterization of Enterovirus 71 Viral Particles Produced from Vero Cells Grown in a Serum-Free Microcarrier Bioreactor System

    PubMed Central

    Liu, Chia-Chyi; Guo, Meng-Shin; Lin, Fion Hsiao-Yu; Hsiao, Kuang-Nan; Chang, Kate Hsuen-Wen; Chou, Ai-Hsiang; Wang, Yu-Chao; Chen, Yu-Ching; Yang, Chung-Shi; Chong, Pele Choi-Sing

    2011-01-01

    Background Enterovirus 71 (EV71) infections manifest most commonly as a childhood exanthema known as hand-foot-and-mouth disease (HFMD) and can cause neurological disease during acute infection. Principal Finding In this study, we describe the production, purification and characterization of EV71 virus produced from Vero cells grown in a five-liter serum-free bioreactor system containing 5 g/L Cytodex 1 microcarrier. The viral titer was >106 TCID50/mL by 6 days post infection when a MOI of 10−5 was used at the initial infection. Two EV71 virus fractions were separated and detected when the harvested EV71 virus concentrate was purified by sucrose gradient zonal ultracentrifugation. The EV71 viral particles detected in the 24–28% sucrose fractions had an icosahedral structure 30–31 nm in diameter and had low viral infectivity and RNA content. Three major viral proteins (VP0, VP1 and VP3) were observed by SDS-PAGE. The EV71 viral particles detected in the fractions containing 35–38% sucrose were 33–35 nm in size, had high viral infectivity and RNA content, and were composed of four viral proteins (VP1, VP2, VP3 and VP4), as shown by SDS-PAGE analyses. The two virus fractions were formalin-inactivated and induced high virus neutralizing antibody responses in mouse immunogenicity studies. Both mouse antisera recognized the immunodominant linear neutralization epitope of VP1 (residues 211–225). Conclusion These results provide important information for cell-based EV71 vaccine development, particularly for the preparation of working standards for viral antigen quantification. PMID:21603631

  4. Aeromonas salmonicida grown in vivo.

    PubMed Central

    Garduño, R A; Thornton, J C; Kay, W W

    1993-01-01

    The virulent fish pathogen Aeromonas salmonicida was rapidly killed in vivo when restricted inside a diffusion chamber implanted intraperitoneally in rainbow trout. After a period of regrowth, the survivors had acquired resistance to host-mediated bacteriolysis, phagocytosis, and oxidative killing, properties which were subsequently lost by growth in vitro. Resistance to bacteriolysis and phagocytosis was associated with a newly acquired capsular layer revealed by acidic polysaccharide staining and electron microscopy. This capsular layer shielded the underlying, regular surface array (S-layer) from immunogold labeling with a primary antibody to the S-layer protein. Resistance to oxidative killing was mediated by a mechanism not associated with the presence of the capsular layer. An attenuated vaccine strain of A. salmonicida grown in vivo failed to express the capsular layer. Consequently, the in vivo-grown cells of this attenuated strain remained as sensitive to bacteriolysis, and as avidly adherent to macrophages, as the in vitro-grown cells. The importance of these new virulence determinants and their relation to the known virulence factors of A. salmonicida are discussed. Images PMID:8359906

  5. Calcium precipitate induced aerobic granulation.

    PubMed

    Wan, Chunli; Lee, Duu-Jong; Yang, Xue; Wang, Yayi; Wang, Xingzu; Liu, Xiang

    2015-01-01

    Aerobic granulation is a novel biotechnology for wastewater treatment. This study refined existing aerobic granulation mechanisms as a sequencing process including formation of calcium precipitate under alkaline pH to form inorganic cores, followed by bacterial attachment and growth on these cores to form the exopolysaccharide matrix. Mature granules comprised an inner core and a matrix layer and a rim layer with enriched microbial strains. The inorganic core was a mix of different crystals of calcium and phosphates. Functional strains including Sphingomonas sp., Paracoccus sp. Sinorhizobium americanum strain and Flavobacterium sp. attached onto the cores. These functional strains promote c-di-GMP production and the expression by Psl and Alg genes for exopolysaccharide production to enhance formation of mature granules.

  6. Aerobic microbial enhanced oil recovery

    SciTech Connect

    Torsvik, T.; Gilje, E.; Sunde, E.

    1995-12-31

    In aerobic MEOR, the ability of oil-degrading bacteria to mobilize oil is used to increase oil recovery. In this process, oxygen and mineral nutrients are injected into the oil reservoir in order to stimulate growth of aerobic oil-degrading bacteria in the reservoir. Experiments carried out in a model sandstone with stock tank oil and bacteria isolated from offshore wells showed that residual oil saturation was lowered from 27% to 3%. The process was time dependent, not pore volume dependent. During MEOR flooding, the relative permeability of water was lowered. Oxygen and active bacteria were needed for the process to take place. Maximum efficiency was reached at low oxygen concentrations, approximately 1 mg O{sub 2}/liter.

  7. Cordyceps militaris Grown on Germinated Soybean Induces G2/M Cell Cycle Arrest through Downregulation of Cyclin B1 and Cdc25c in Human Colon Cancer HT-29 Cells

    PubMed Central

    Mollah, Mohammad Lalmoddin; Park, Dong Ki; Park, Hye-Jin

    2012-01-01

    Cordyceps militaris (CM) is an insect-borne fungus that has been used in traditional Chinese medicine because of its wide range of pharmacological activities. In this paper, we studied CM grown on germinated soybean (GSC) and investigated the possible mechanisms underlying antiproliferative effect of GSC on HT-29 human colon cancer cells. In comparison with CM extracts and germinated soybean (GS) BuOH extracts, BuOH extracts of GSC showed remarkable inhibitory and antiproliferative effects on HT-29 colon cancer cells. After GSC treatment, HT-29 cells became smaller and irregular in shape. High G2/M phase cell populations were observed in the GSC-treated group. The levels of cyclin B1 and Cdc25 in the GSC-treated group were lower than those in the control group. These findings suggest that GSC BuOH extracts might act as an effective anti-proliferative agent by inducing G2/M cell cycle arrest in colon cancer cells. PMID:22474493

  8. Cordyceps militaris Grown on Germinated Soybean Induces G2/M Cell Cycle Arrest through Downregulation of Cyclin B1 and Cdc25c in Human Colon Cancer HT-29 Cells.

    PubMed

    Mollah, Mohammad Lalmoddin; Park, Dong Ki; Park, Hye-Jin

    2012-01-01

    Cordyceps militaris (CM) is an insect-borne fungus that has been used in traditional Chinese medicine because of its wide range of pharmacological activities. In this paper, we studied CM grown on germinated soybean (GSC) and investigated the possible mechanisms underlying antiproliferative effect of GSC on HT-29 human colon cancer cells. In comparison with CM extracts and germinated soybean (GS) BuOH extracts, BuOH extracts of GSC showed remarkable inhibitory and antiproliferative effects on HT-29 colon cancer cells. After GSC treatment, HT-29 cells became smaller and irregular in shape. High G2/M phase cell populations were observed in the GSC-treated group. The levels of cyclin B1 and Cdc25 in the GSC-treated group were lower than those in the control group. These findings suggest that GSC BuOH extracts might act as an effective anti-proliferative agent by inducing G2/M cell cycle arrest in colon cancer cells.

  9. Effect of passivation layer grown by atomic layer deposition and sputtering processes on Si quantum dot superlattice to generate high photocurrent for high-efficiency solar cells

    NASA Astrophysics Data System (ADS)

    Maksudur Rahman, Mohammad; Higo, Akio; Sekhar, Halubai; Erman Syazwan, Mohd; Hoshi, Yusuke; Usami, Noritaka; Samukawa, Seiji

    2016-03-01

    The effect of passivation films on a Si quantum dot superlattice (QDSL) was investigated to generate high photocurrent in solar-cell applications. Three types of passivation films, sputter-grown amorphous silicon carbide (a-SiC), hydrogenated a-SiC (a-SiC:H), and atomic-layer-deposited aluminum oxide (ALD-Al2O3), were used to passivate the Si QDSLs containing a stack of four 4 nm Si nanodisks (NDs) and 2 nm silicon carbide (SiC) films fabricated by neutral beam etching (NBE). Because of the high surface-to-volume ratio typically present in quantum Si-NDs formed in the top-down NBE process, there is a tendency to form larger surface dangling bonds on untreated Si-ND surfaces as well as to have short distance (<10 nm) between high-aspect-ratio nanopillars of stacked 4 nm Si-NDs/2 nm SiC films, which conventionally sputter SiC films cannot uniformly cover. Therefore, we optimized the passivation techniques with an ALD-Al2O3 film. Scanning electron microscopy (SEM) analysis helped to explain the surface morphology before and after the passivation of the QDSLs. After the completion of the passivation process, the quality of the top surface films of the QDSLs was analyzed from the surface roughness by atomic force microscopy (AFM) analysis, which revealed that ALD-Al2O3 passivated films had the smallest roughness (RMS) of 1.09 nm with respect to sputter-grown a-SiC (RMS: 1.75 nm) and a-SiC:H (RMS: 1.54 nm) films. Conductive atomic force microscopy (CAFM) revealed that ALD-Al2O3 passivation decreased the surface-leakage current as a result of proper passivation of side-wall surface defects in the QDSLs. The carrier transport characteristics were extracted from the QDSLs using the photovoltaic (PV) properties of p++/i/n+ solar cells, where the QDSLs consisted of different passivation layers acting as intermediate layers (i-layers) between the high-doping-density p++ Si (1 × 1020 cm-3) and n+ Si (1 × 1019 cm-3) substrates. High-doping-density p++ Si acted as a hole

  10. Aerobic Microbial Degradation of Glucoisosaccharinic Acid

    PubMed Central

    Strand, S. E.; Dykes, J.; Chiang, V.

    1984-01-01

    α-Glucoisosaccharinic acid (GISA), a major by-product of kraft paper manufacture, was synthesized from lactose and used as the carbon source for microbial media. Ten strains of aerobic bacteria capable of growth on GISA were isolated from kraft pulp mill environments. The highest growth yields were obtained with Ancylobacter spp. at pH 7.2 to 9.5. GISA was completely degraded by cultures of an Ancylobacter isolate. Ancylobacter cell suspensions consumed oxygen and produced carbon dioxide in response to GISA addition. A total of 22 laboratory strains of bacteria were tested, and none was capable of growth on GISA. GISA-degrading isolates were not found in forest soils. Images PMID:16346467

  11. Optical and electrical characterization of CdS-Glycine thin films with ammonia free buffer grown at different temperatures for solar cells applications

    NASA Astrophysics Data System (ADS)

    Berman-Mendoza, D.; Quiñones-Urías, D.; Ferra-González, S.; Vera-Marquina, A.; Rojas-Hernández, A.; Gómez Fuentes, R.; García-Juárez, A.; Leal-Cruz, A. L.; Ramos-Carrasco, A.

    2013-11-01

    In this work we report the fabrication and electro-optical characterization of CdS thin films using glycine as complexing agent with ammonia and ammonia free buffer by the Chemical Bath Deposition (CBD) method. The CdS thin films were grown at different temperatures of 50, 60, 70 and 80 °C in a thermal water bath. The morphology of these films was determined using atomic force microscopy; the resultant films were homogeneous, well adhered to the substrate, and specularly reflecting with a varying color depending on the deposition temperature. Transmittance and reflectance measurements of thermally treated CdS films were carried to study the effect of the ammonia buffer on its optical properties and bandgap. The crystallinity of the CdS thin films was determined by means of X Ray diffraction measurements. Therefore, for this study, an ammonia-free complexing agent has been taken for the deposition of CdS. Among different methods, which are being used for the preparation of CdS films, Chemical Bath Deposition (CBD) is the most attractive due to its low cost, easy to handle and large possibilities regarding doping and deposition on various substrates. In particular it can be used to easily obtain field effect devices by depositing CdS thin films over a SiO2/Si substrate. Heterostructures with interesting physical properties can be imagined, realized and tested in this way.. Structures CdS/PbS also were realized and have shown good solar cell characteristics.

  12. Analysis of thymic stromal cell subpopulations grown in vitro on extracellular matrix in defined medium. II. Cytokine activities in murine thymic epithelial and mesenchymal cell culture supernatants.

    PubMed

    Eshel, I; Savion, N; Shoham, J

    1990-03-01

    Two morphologically distinct primary cultures of murine thymic stroma were established and found to be of epithelial (MTEC) and mesenchymal (MTMC) origin. These cultures were generated by selective conditions of tissue disruption and were maintained on extracellular matrix in defined medium. Culture supernatants (CS) from these cultures (EC-CS and MC-CS respectively), were tested for cytokine production and for effects on thymocyte maturation. Both supernatants displayed the activities of IL-3 and of granulocyte/macrophage-CSF and not of IL-1, -2, -4, or IFN. In addition they were found to be mitogenic to murine thymocytes in a "spontaneous" [3H]TdR incorporation assay. The two supernatants differed, however, in their effect on Con A stimulation. EC-CS had a strong enhancing effect, both when used for preincubation (18 h) before Con A stimulation or when present simultaneously with it. MC-CS had a small inconsistent effect under these conditions. Also EC-CS enhanced IL-2 and IL-3 production by thymocytes. The responsive thymocyte subpopulation was the one that does not bind peanut agglutinin. CS of an established thymic epithelial cell line displayed only part of these activities at a considerably lower level. CS from primary kidney cell culture was completely devoid of activity. The results suggest that primary thymic stromal cell cultures, cultivated under the defined conditions described here, may better preserve physiologic secretory activities, and probably also other cell functions, compared with established cell lines. Furthermore, the results are compatible with the hypothesis that the soluble factors, secreted by thymic stromal cells, are active on either very early or late stages of thymic differentiation, whereas the main intrathymic stages of differentiation are conceivable dependent primarily on direct contact with stromal cells.

  13. Chemotaxis without Conventional Two-Component System, Based on Cell Polarity and Aerobic Conditions in Helicity-Switching Swimming of Spiroplasma eriocheiris

    PubMed Central

    Liu, Peng; Zheng, Huajun; Meng, Qingguo; Terahara, Natsuho; Gu, Wei; Wang, Shengyue; Zhao, Guoping; Nakane, Daisuke; Wang, Wen; Miyata, Makoto

    2017-01-01

    Spiroplasma eriocheiris is a pathogen that causes mass mortality in Chinese mitten crab, Eriocheir sinensis. S. eriocheiris causes tremor disease and infects almost all of the artificial breeding crustaceans, resulting in disastrous effects on the aquaculture economy in China. S. eriocheiris is a wall-less helical bacterium, measuring 2.0 to 10.0 μm long, and can swim up to 5 μm per second in a viscous medium without flagella by switching the cell helicity at a kink traveling from the front to the tail. In this study, we showed that S. eriocheiris performs chemotaxis without the conventional two-component system, a system commonly found in bacterial chemotaxis. The chemotaxis of S. eriocheiris was observed more clearly when the cells were cultivated under anaerobic conditions. The cells were polarized as evidenced by a tip structure, swimming in the direction of the tip, and were shown to reverse their swimming direction in response to attractants. Triton X-100 treatment revealed the internal structure, a dumbbell-shaped core in the tip that is connected by a flat ribbon, which traces the shortest line in the helical cell shape from the tip to the other pole. Sixteen proteins were identified as the components of the internal structure by mass spectrometry, including Fibril protein and four types of MreB proteins. PMID:28217108

  14. A survey of culturable aerobic and anaerobic marine bacteria in de novo biofilm formation on natural substrates in St. Andrews Bay, Scotland.

    PubMed

    Finnegan, Lucy; Garcia-Melgares, Manuel; Gmerek, Tomasz; Huddleston, W Ryan; Palmer, Alexander; Robertson, Andrew; Shapiro, Sarah; Unkles, Shiela E

    2011-10-01

    This study reports a novel study of marine biofilm formation comprising aerobic and anaerobic bacteria. Samples of quartz and feldspar, minerals commonly found on the earth, were suspended 5 m deep in the North Sea off the east coast of St. Andrews, Scotland for 5 weeks. The assemblage of organisms attached to these stones was cultivated under aerobic and anaerobic conditions in the laboratory. Bacteria isolated on Marine Agar 2216 were all Gram-negative and identified to genus level by sequencing the gene encoding 16S rRNA. Colwellia, Maribacter, Pseudoaltermonas and Shewanella were observed in aerobically-grown cultures while Vibrio was found to be present in both aerobic and anaerobic cultures. The obligate anaerobic bacterium Psychrilyobacter atlanticus, a recently defined genus, was identified as a close relative of isolates grown anaerobically. The results provide valuable information as to the main players that attach and form de novo biofilms on common minerals in sea water.

  15. Melatonin production in an aerobic photosynthetic bacterium: an evolutionarily early association with darkness.

    PubMed

    Tilden, A R; Becker, M A; Amma, L L; Arciniega, J; McGaw, A K

    1997-03-01

    Melatonin was measured in a species of aerobic photosynthetic bacteria, Erythrobacter longus, grown in either constant light or constant dark. A radioimmunoassay was used to quantify melatonin levels and thin-layer chromatography to confirm the identity of melatonin immunoactivity. Melatonin levels were significantly higher (nearly 2.3-fold) in the dark-grown than in the light-grown samples. Also, the homogenates of the dark-grown bacteria retained melatonin-producing enzymatic activity, whereas the light-grown homogenates did not; melatonin levels extracted from the dark-grown homogenates increased with increasing extraction time, reaching as high as 29.2 ng.mg-1 protein at 120 min. Removal of membrane fragments from homogenates did not influence melatonin levels in light-grown homogenate, but this procedure increased melatonin levels in dark-grown homogenate, indicating that at least some of the enzymes in the pathway of melatonin production are not membrane-bound. This study is the second to demonstrate the presence of melatonin at the prokaryotic level, supporting the evidence that melatonin appeared very early in evolution. Its function in prokaryotes has not been determined, but may relate to its antioxidative actions.

  16. Lower limb loading in step aerobic dance.

    PubMed

    Wu, H-W; Hsieh, H-M; Chang, Y-W; Wang, L-H

    2012-11-01

    Participation in aerobic dance is associated with a number of lower extremity injuries, and abnormal joint loading seems to be a factor in these. However, information on joint loading is limited. The purpose of this study was to investigate the kinetics of the lower extremity in step aerobic dance and to compare the differences of high-impact and low-impact step aerobic dance in 4 aerobic movements (mambo, kick, L step and leg curl). 18 subjects were recruited for this study. High-impact aerobic dance requires a significantly greater range of motion, joint force and joint moment than low-impact step aerobic dance. The peak joint forces and moments in high-impact step aerobic dance were found to be 1.4 times higher than in low-impact step aerobic dance. Understanding the nature of joint loading may help choreographers develop dance combinations that are less injury-prone. Furthermore, increased knowledge about joint loading may be helpful in lowering the risk of injuries in aerobic dance instructors and students.

  17. Aerobic nitroreduction of dehydrochloramphenicol by bone marrow.

    PubMed

    Isildar, M; Abou-Khalil, W H; Jimenez, J J; Abou-Khalil, S; Yunis, A A

    1988-06-30

    It has been previously demonstrated that dehydrochloramphenicol (DH-CAP), a bacterial metabolite of chloramphenicol, induces DNA single strand breaks in intact cells and is profoundly more cytotoxic than chloramphenicol (CAP). In view of previous observations relating genotoxicity of nitrocompounds to their nitroreduction by the target tissue, we studied the nitroreduction of DH-CAP by human and rabbit bone marrow. Nitroreduction by tissue homogenates was determined by the Bratton Marshall colorimetric assay and by high-performance liquid chromatography (HPLC). Nitroreduction of DH-CAP by bone marrow cell homogenates was observed under aerobic conditions and the reduction was both cell concentration- and time-dependent. The formation of the amino product aminodehydrochloramphenicol was confirmed by HPLC. Reduction by other tissues including human liver, Raji cells, and HL-60 tumors was also observed. These results suggest that genotoxicity of DH-CAP may be related to its nitroreduction by the target tissue with in situ production of toxic intermediates. Together with previous studies, these observations lend support to the thesis that the p-NO2 group may be the structural feature underlying aplastic anemia from CAP.

  18. Room-temperature wafer bonded InGaP/GaAs//InGaAsP/InGaAs four-junction solar cell grown by all-solid state molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Dai, Pan; Lu, Shulong; Uchida, Shiro; Ji, Lian; Wu, Yuanyuan; Tan, Ming; Bian, Lifeng; Yang, Hui

    2016-01-01

    An InGaP/GaAs tandem cell on a GaAs substrate and an InGaAsP/InGaAs tandem cell on an InP substrate were grown separately by all-solid-state molecular beam epitaxy. A room-temperature direct wafer-bonding technique was used to integrate these subcells into an InGaP/GaAs//InGaAsP/InGaAs wafer-bonded solar cell, which resulted in an abrupt interface with low resistance and high optical transmission. The current-matching design for the base layer thickness of each cell was investigated. The resulting efficiency of the four-junction solar cell was 42.0% at 230 suns, which demonstrates the great potential of the room-temperature wafer-bonding technique to achieve high conversion efficiency for cells with four or more junctions.

  19. Generating controlled reducing environments in aerobic recombinant Escherichia coli fermentations: effects on cell growth, oxygen uptake, heat shock protein expression, and in vivo CAT activity.

    PubMed

    Gill, R T; Cha, H J; Jain, A; Rao, G; Bentley, W E

    1998-07-20

    The independent control of culture redox potential (CRP) by the regulated addition of a reducing agent, dithiothreitol (DTT) was demonstrated in aerated recombinant Escherichia coli fermentations. Moderate levels of DTT addition resulted in minimal changes to specific oxygen uptake, growth rate, and dissolved oxygen. Excessive levels of DTT addition were toxic to the cells resulting in cessation of growth. Chloramphenicol acetyltransferase (CAT) activity (nmoles/microgram total protein min.) decreased in batch fermentation experiments with respect to increasing levels of DTT addition. To further investigate the mechanisms affecting CAT activity, experiments were performed to assay heat shock protein expression and specific CAT activity (nmoles/microgram CAT min.). Expression of such molecular chaperones as GroEL and DnaK were found to increase after addition of DTT. Additionally, sigma factor 32 (sigma32) and several proteases were seen to increase dramatically during addition of DTT. Specific CAT activity (nmoles/microgram CAT min. ) varied greatly as DTT was added, however, a minimum in activity was found at the highest level of DTT addition in E. coli strains RR1 [pBR329] and JM105 [pROEX-CAT]. In conjunction, cellular stress was found to reach a maximum at the same levels of DTT. Although DTT addition has the potential for directly affecting intracellular protein folding, the effects felt from the increased stress within the cell are likely the dominant effector. That the effects of DTT were measured within the cytoplasm of the cell suggests that the periplasmic redox potential was also altered. The changes in specific CAT activity, molecular chaperones, and other heat shock proteins, in the presence of minimal growth rate and oxygen uptake alterations, suggest that the ex vivo control of redox potential provides a new process for affecting the yield and conformation of heterologous proteins in aerated E. coli fermentations.

  20. Investigation of anodic and chemical oxides grown on p-type InP with applications to surface passivation for n(+)-p solar cell fabrication

    NASA Technical Reports Server (NTRS)

    Faur, Maria; Faur, Mircea; Goradia, Manju; Goradia, Chandra; Jenkins, Phillip; Jayne, Douglas; Weinberg, Irving

    1991-01-01

    Most of the previously reported InP anodic oxides were grown on a n-type InP with applications to fabrication of MISFET structures and were described as a mixture of In2O3 and P2O5 stoichiometric compounds or nonstoichiometric phases which have properties similar to crystalline compounds In(OH)3, InPO4, and In(PO3)3. Details of the compositional change of the anodic oxides grown under different anodization conditions were previously reported. The use of P-rich oxides grown either by anodic or chemical oxidation are investigated for surface passivation of p-type InP and as a protective cap during junction formation by closed-ampoule sulfur diffusion. The investigation is based on but not limited to correlations between PL intensity and X-ray photoelectron spectroscopy (XPS) chemical composition data.

  1. Aerobic Fermentation of D-Xylose to Ethanol by Clavispora sp

    PubMed Central

    Nigam, J. N.; Margaritis, A.; Lachance, M. A.

    1985-01-01

    Eleven strains of an undescribed species of Clavispora fermented D-xylose directly to ethanol under aerobic conditions. Strain UWO(PS)83-877-1 was grown in a medium containing 2% D-xylose and 0.5% yeast extract, and the following results were obtained: ethanol yield coefficient (ethanol/D-xylose), 0.29 g g−1 (57.4% of theoretical); cell yield coefficient (dry biomass/D-xylose), 0.25 g g−1; maximum ethanol concentration, 5.9 g liter−1; maximum volumetric ethanol productivity, 0.11 g liter−1 h−1. With initial D-xylose concentrations of 40, 60, and 80 g liter−1, maximum ethanol concentrations of 8.8, 10.9, and 9.8 g liter−1 were obtained, respectively (57.2, 57.1, and 48.3% of theoretical). Ethanol was found to inhibit the fermentation of D-xylose (Kp = 0.58 g liter−1) more than the fermentation of glucose (Kp = 6.5 g liter−1). The performance of this yeast compared favorably with that reported for some other D-xylose-fermenting yeasts. PMID:16346910

  2. Control of aerobic glycolysis in the brain in vitro.

    PubMed

    Benjamin, A M; Verjee, Z H

    1980-09-01

    Protoveratrine-(5 microM) stimulated aerobic glycolysis of incubated rat brain cortex slices that accompanies the enhanced neuronal influx of Na+ is blocked by tetrodotoxin (3 microM) and the local anesthetics, cocaine (0.1 mM) and lidocaine (0.5 mM). On the other hand, high [K+]-stimulated aerobic glycolysis that accompanies the acetylcholine-sensitive enhanced glial uptakes of Na+ and water is unaffected by acetylcholine (2 mM). Experiments done under a variety of metabolic conditions show that there exists a better correlation between diminished ATP content of the tissue and enhanced aerobic glycolysis than between tissue ATP and the ATP-dependent synthesis of glutamine. Whereas malonate (2 mM) and amino oxyacetate (5 mM) suppress ATP content and O2 uptake, stimulate lactate formation, but have little effect on glutamine levels, fluoroacetate (3 mM) suppresses glutamine synthesis in glia, presumably by suppressing the operation of the citric acid cycle, with little effect on ATP content, O2 uptake, and lactate formation. Exogenous citrate (5 mM), which may be transported and metabolized in glia but not in neurons, inhibits lactate formation by cell free acetone-dried powder extracts of brain cortex but not by brain cortex slices. These results suggest that the neuron is the major site of stimulated aerobic glycolysis in the brain, and that under our experimental conditions glycolysis in glia is under lesser stringent metabolic control than that in the neuron. Stimulation of aerobic glycolysis by protoveratrine occurs due to diminution of the energy charge of the neuron as a result of stimulation of the sodium pump following tetrodotoxin-sensitive influx of Na+; stimulation by high [K+], NH4+, or Ca2+ deprivation occurs partly by direct stimulation of key enzymes of glycolysis and partly by a fall in the tissue ATP concentration.

  3. Aerobic granulation of aggregating consortium X9 isolated from aerobic granules and role of cyclic di-GMP.

    PubMed

    Wan, Chunli; Yang, Xue; Lee, Duu-Jong; Wang, Xin-Yue; Yang, Qiaoli; Pan, Xiangliang

    2014-01-01

    This study monitored the granulation process of an aggregating functional consortium X9 that was consisted of Pseudomonas putida X-1, Acinetobacter sp. X-2, Alcaligenes sp. X-3 and Comamonas testosteroni X-4 in shaken reactors. The growth curve of X9 was fit using logistic model as follows y=1.49/(1+21.3*exp(-0.33x)), the maximum specific cell growth rate for X9 was 0.33 h(-1). Initially X9 consumed polysaccharides (PS) and secreted proteins (PN) to trigger granulation. Then X9 grew in biomass and formed numerous micro-granules, driven by increasing hydrophobicity of cell membranes and of accumulated extracellular polymeric substances (EPS). In later stage the intracellular cyclic diguanylate (c-di-GMP) was at high levels for inhibiting bacteria swarming motility, thereby promotion formation of large aerobic granules. The findings reported herein advise the way to accelerate granule formation and to stabilize operation in aerobic granular reactors.

  4. Protein, free amino acid, phenloic, ß-carotene, and lycopene content, and antioxidative and cancer cell inhibitory effects of 12 greenhouse-grown commercial cherry tomato varieties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The content of water, free amino acids, amino acid metabolites, crude protein, the carotene pigments ß-carotene and lycopene, and 9 characterized and 2 incompletely characterized individual phenolic (flavonoid) compounds of 12 greenhouse-grown cherry tomato varieties of various colors (green, yellow...

  5. Skeletal Muscle Hypertrophy after Aerobic Exercise Training

    PubMed Central

    Konopka, Adam R.; Harber, Matthew P.

    2014-01-01

    Current dogma suggests aerobic exercise training has minimal effect on skeletal muscle size. We and others have demonstrated that aerobic exercise acutely and chronically alters protein metabolism and induces skeletal muscle hypertrophy. These findings promote an antithesis to the status quo by providing novel perspective on skeletal muscle mass regulation and insight into exercise-countermeasures for populations prone to muscle loss. PMID:24508740

  6. Aerobic rice mechanization: techniques for crop establishment

    NASA Astrophysics Data System (ADS)

    Khusairy, K. M.; Ayob, H.; Chan, C. S.; Fauzi, M. I. Mohamed; Mohamad Fakhrul, Z. O.; Shahril Shah, G. S. M.; Azlan, O.; Rasad, M. A.; Hashim, A. M.; Arshad, Z.; E, E. Ibrahim; Saifulizan, M. N.

    2015-12-01

    Rice being the staple food crops, hundreds of land races in it makes the diversity of rice crops. Aerobic rice production was introduced which requires much less water input to safeguard and sustain the rice production and conserve water due to decreasing water resources, climatic changes and competition from urban and industrial users. Mechanization system plays an important role for the success of aerobic rice cultivation. All farming activities for aerobic rice production are run on aerobic soil conditions. Row seeder mechanization system is developed to replace conventional seeding technique on the aerobic rice field. It is targeted for small and the large scale aerobic rice farmers. The aero - seeder machine is used for the small scale aerobic rice field, while the accord - seeder is used for the large scale aerobic rice field. The use of this mechanization machine can eliminate the tedious and inaccurate seeding operations reduce labour costs and increases work rate. The machine is easy to operate and it can increase crop establishment rate. It reduce missing hill, increasing planting and crop with high yield can be produce. This machine is designed for low costs maintenance and it is easy to dismantle and assemble during maintenance and it is safe to be used.

  7. Aerobic Fitness for the Moderately Retarded.

    ERIC Educational Resources Information Center

    Bauer, Dan

    1981-01-01

    Intended for physical education teachers, the booklet offers ideas for incorporating aerobic conditioning into programs for moderately mentally retarded students. An explanation of aerobic fitness and its benefits is followed by information on initiating a fitness program with evaluation of height, weight, body fat, resting heart rate, and…

  8. Aerobic Dancing--A Rhythmic Sport.

    ERIC Educational Resources Information Center

    Sorensen, Jacki

    Fitness programs now and in the future must offer built-in cardiovascular conditioning, variety, novelty, and change to meet the physical, mental, and emotional needs of our society. Aerobic dancing (dancing designed to train and strengthen the heart, lungs, and vascular system) is one of the first indoor group Aerobic exercise programs designed…

  9. Immobilisation increases yeast cells' resistance to dehydration-rehydration treatment.

    PubMed

    Borovikova, Diana; Rozenfelde, Linda; Pavlovska, Ilona; Rapoport, Alexander

    2014-08-20

    This study was performed with the goal of revealing if the dehydration procedure used in our new immobilisation method noticeably decreases the viability of yeast cells in immobilised preparations. Various yeasts were used in this research: Saccharomyces cerevisiae cells that were rather sensitive to dehydration and had been aerobically grown in an ethanol-containing medium, a recombinant strain of S. cerevisiae grown in aerobic conditions which were completely non-resistant to dehydration and an anaerobically grown bakers' yeast strain S. cerevisiae, as well as a fairly resistant Pichia pastoris strain. Experiments performed showed that immobilisation of all these strains essentially increased their resistance to a dehydration-rehydration treatment. The increase of cells' viability (compared with control cells dehydrated in similar conditions) was from 30 to 60%. It is concluded that a new immobilisation method, which includes a dehydration stage, does not lead to an essential loss of yeast cell viability. Correspondingly, there is no risk of losing the biotechnological activities of immobilised preparations. The possibility of producing dry, active yeast preparations is shown, for those strains that are very sensitive to dehydration and which can be used in biotechnology in an immobilised form. Finally, the immobilisation approach can be used for the development of efficient methods for the storage of recombinant yeast strains.

  10. Aerobic fitness testing: an update.

    PubMed

    Stevens, N; Sykes, K

    1996-12-01

    This study confirms that all three tests are reliable tools for the assessment of cardiorespiratory fitness and the prediction of aerobic capacity. While this particular study consisted of active, youthful subjects, subsequent studies at University College Chester have found similar findings with larger databases and a wider cross-section of subjects. The Astrand cycle test and Chester step test are submaximal tests with error margins of 5-15 per cent and therefore, not as precise as maximal testing. However, they still give a reasonably accurate reflection of an individual's fitness without the cost, time, effort and risk on the part of the subject. The bleep test is a low-cost maximal test designed for well-motivated, active individuals who are used to running to physical exhaustion. Used on other groups, results will not accurately reflect cardiorespiratory fitness values. While all three tests have inherent advantages and disadvantages, perhaps the most important factors are the knowledge and skills of the tester. Without a sound understanding of the physiological principles underlying these tests, and the ability to conduct an accurate assessment and evaluation of results in a knowledgeable and meaningful way, then the credibility of the tests and the results become suspect. However, used correctly, aerobic capacity tests can provide valuable baseline data about the fitness levels of individuals and data from which exercise programmes may be developed. The tests also enable fitness improvements to be monitored, help to motivate participants by establishing reasonable and achievable goals, assist in risk stratification and facilitate participants' education about the importance of physical fitness for work and for life. Since this study was completed, further tests have been repeated on 140 subjects of a wider age and ability range. This large database confirms the results found in this study.

  11. Aerobic glycolysis and lymphocyte transformation

    PubMed Central

    Hume, David A.; Radik, Judith L.; Ferber, Ernst; Weidemann, Maurice J.

    1978-01-01

    1. The role of enhanced aerobic glycolysis in the transformation of rat thymocytes by concanavalin A has been investigated. Concanavalin A addition doubled [U-14C]glucose uptake by rat thymocytes over 3h and caused an equivalent increased incorporation into protein, lipids and RNA. A disproportionately large percentage of the extra glucose taken up was converted into lactate, but concanavalin A also caused a specific increase in pyruvate oxidation, leading to an increase in the percentage contribution of glucose to the respiratory fuel. 2. Acetoacetate metabolism, which was not affected by concanavalin A, strongly suppressed pyruvate oxidation in the presence of [U-14C]glucose, but did not prevent the concanavalin A-induced stimulation of this process. Glucose uptake was not affected by acetoacetate in the presence or absence of concanavalin A, but in each case acetoacetate increased the percentage of glucose uptake accounted for by lactate production. 3. [3H]Thymidine incorporation into DNA in concanavalin A-treated thymocyte cultures was sensitive to the glucose concentration in the medium in a biphasic manner. Very low concentrations of glucose (25μm) stimulated DNA synthesis half-maximally, but maximum [3H]thymidine incorporation was observed only when the glucose concentration was raised to 1mm. Lactate addition did not alter the sensitivity of [3H]-thymidine uptake to glucose, but inosine blocked the effect of added glucose and strongly inhibited DNA synthesis. 4. It is suggested that the major function of enhanced aerobic glycolysis in transforming lymphocytes is to maintain higher steady-state amounts of glycolytic intermediates to act as precursors for macromolecule synthesis. PMID:310305

  12. Transcriptional Regulation of Aerobic Metabolism in Pichia pastoris Fermentation

    PubMed Central

    Zhang, Biao; Li, Baizhi; Chen, Dai; Zong, Jie; Sun, Fei; Qu, Huixin; Liang, Chongyang

    2016-01-01

    In this study, we investigated the classical fermentation process in Pichia pastoris based on transcriptomics. We utilized methanol in pichia yeast cell as the focus of our study, based on two key steps: limiting carbon source replacement (from glycerol to methonal) and fermentative production of exogenous proteins. In the former, the core differential genes in co-expression net point to initiation of aerobic metabolism and generation of peroxisome. The transmission electron microscope (TEM) results showed that yeast gradually adapted methanol induction to increased cell volume, and decreased density, via large number of peroxisomes. In the fermentative production of exogenous proteins, the Gene Ontology (GO) mapping results show that PAS_chr2-1_0582 played a vital role in regulating aerobic metabolic drift. In order to confirm the above results, we disrupted PAS_chr2-1_0582 by homologous recombination. Alcohol consumption was equivalent to one fifth of the normal control, and fewer peroxisomes were observed in Δ0582 strain following methanol induction. In this study we determined the important core genes and GO terms regulating aerobic metabolic drift in Pichia, as well as developing new perspectives for the continued development within this field. PMID:27537181

  13. Fit women are not able to use the whole aerobic capacity during aerobic dance.

    PubMed

    Edvardsen, Elisabeth; Ingjer, Frank; Bø, Kari

    2011-12-01

    Edvardsen, E, Ingjer, F, and Bø, K. Fit women are not able to use the whole aerobic capacity during aerobic dance. J Strength Cond Res 25(12): 3479-3485, 2011-This study compared the aerobic capacity during maximal aerobic dance and treadmill running in fit women. Thirteen well-trained female aerobic dance instructors aged 30 ± 8.17 years (mean ± SD) exercised to exhaustion by running on a treadmill for measurement of maximal oxygen uptake (VO(2)max) and peak heart rate (HRpeak). Additionally, all subjects performed aerobic dancing until exhaustion after a choreographed videotaped routine trying to reach the same HRpeak as during maximal running. The p value for statistical significance between running and aerobic dance was set to ≤0.05. The results (mean ± SD) showed a lower VO(2)max in aerobic dance (52.2 ± 4.02 ml·kg·min) compared with treadmill running (55.9 ± 5.03 ml·kg·min) (p = 0.0003). Further, the mean ± SD HRpeak was 182 ± 9.15 b·min in aerobic dance and 192 ± 9.62 b·min in treadmill running, giving no difference in oxygen pulse between the 2 exercise forms (p = 0.32). There was no difference in peak ventilation (aerobic dance: 108 ± 10.81 L·min vs. running: 113 ± 11.49 L·min). In conclusion, aerobic dance does not seem to be able to use the whole aerobic capacity as in running. For well endurance-trained women, this may result in a lower total workload at maximal intensities. Aerobic dance may therefore not be as suitable as running during maximal intensities in well-trained females.

  14. Graphic Grown Up

    ERIC Educational Resources Information Center

    Kim, Ann

    2009-01-01

    It's no secret that children and YAs are clued in to graphic novels (GNs) and that comics-loving adults are positively giddy that this format is getting the recognition it deserves. Still, there is a whole swath of library card-carrying grown-up readers out there with no idea where to start. Splashy movies such as "300" and "Spider-Man" and their…

  15. Influence of organic and inorganic growth supplements on the aerobic biodegradation of chlorobenzoic acids.

    PubMed

    Fava, F; Armenante, P M; Kafkewitz, D; Marchetti, L

    1995-04-01

    The effect of yeast extract and its less complex substituents on the rate of aerobic dechlorination of 2-chlorobenzoic acid (2-ClBZOH) and 2,5-dichlorobenzoic acid (2,5-Cl2BZOH) by Pseudomonas sp. CPE2 strain, and of 3-chlorobenzoic acid (3-ClBZOH), 4-chlorobenzoic acid (4-ClBZOH) and 3,4-dichlorobenzoic acid (3,4-Cl2BZOH) by Alcaligenes sp. CPE3 strain were investigated. Yeast extract at 50 mg/l increased the average dechlorination rate of 200 mg/l of 4-ClBZOH, 2,5-Cl2BZOH, 3,4-Cl2BZOH, 3-ClBZOH and 2-ClBZOH by about 75%, 70%, 55%, 7%, and 1%, respectively. However, in the presence of yeast extract the specific dechlorination activity of CPE2 and CPE3 cells (per unit biomass) was always lower than without yeast extract, although it increased significantly during the exponential growth phase. When a mixed vitamin solution or a mixed trace element solution was used instead of yeast extract the rate of 4-ClBZOH dechlorination increased by 30%-35%, whereas the rate of 2,5-Cl2BZOH and 3,4-Cl2BZOH dechlorination increased by only 2%-10%. The presence of vitamins or trace elements also resulted in a specific dechlorination activity that was generally higher than that observed for the same cells grown solely on chlorobenzoic acid. The results of this work indicate that yeast extract, a complex mixture of readily oxidizable carbon sources, vitamins, and trace elements, enhances the growth and the dechlorination activity of CPE2 and CPE3 cells, thus resulting in an overall increase in the rate of chlorobenzoic acid utilization and dechlorination.

  16. Interface ferroelectric transition near the gap-opening temperature in a single-unit-cell FeSe film grown on Nb-Doped SrTiO3 substrate.

    PubMed

    Cui, Y-T; Moore, R G; Zhang, A-M; Tian, Y; Lee, J J; Schmitt, F T; Zhang, W-H; Li, W; Yi, M; Liu, Z-K; Hashimoto, M; Zhang, Y; Lu, D-H; Devereaux, T P; Wang, L-L; Ma, X-C; Zhang, Q-M; Xue, Q-K; Lee, D-H; Shen, Z-X

    2015-01-23

    We report findings of strong anomalies in both mutual inductance and inelastic Raman spectroscopy measurements of single-unit-cell FeSe film grown on Nb-doped SrTiO3, which occur near the temperature where the superconductinglike energy gap opens. Analysis suggests that the anomaly is associated with a broadened ferroelectric transition in a thin layer near the FeSe/SrTiO3 interface. The coincidence of the ferroelectric transition and gap-opening temperatures adds credence to the central role played by the film-substrate interaction on the strong Cooper pairing in this system. We discuss scenarios that could explain such a coincidence.

  17. The effects of aerobic training on children's creativity, self-perception, and aerobic power.

    PubMed

    Herman-Tofler, L R; Tuckman, B W

    1998-10-01

    The article examines whether participation in an aerobic exercise program (AE), as compared with a traditional physical education class (PE), significantly increased children's perceived athletic competence, physical appearance, social acceptance, behavioral conduct, and global self-worth; increased their figural creativity; and improved aerobic power as measured by an 800-meter run around a track. Further research on the effects of different types of AE is discussed, as well as the need for aerobic conditioning in the elementary school.

  18. Conditioning and Aerobics for Older Americans.

    ERIC Educational Resources Information Center

    Hansen, Joyce

    1980-01-01

    A class designed for the maintenance and gradual improvement of senior citizens' physical fitness includes relaxation training, flexibility and stretching exercises, interval training activities (designed as a link between less strenuous exercise and more strenuous activities), and aerobic exercises. (CJ)

  19. The rise of oxygen and aerobic biochemistry.

    PubMed

    Saito, Mak A

    2012-01-11

    Analysis of conserved protein folding domains across extant genomes by Kim et al. in this issue of Structure provides insights into the timing of some of the earliest aerobic metabolisms to arise on Earth.

  20. Neuromodulation of Aerobic Exercise—A Review

    PubMed Central

    Heijnen, Saskia; Hommel, Bernhard; Kibele, Armin; Colzato, Lorenza S.

    2016-01-01

    Running, and aerobic exercise in general, is a physical activity that increasingly many people engage in but that also has become popular as a topic for scientific research. Here we review the available studies investigating whether and to which degree aerobic exercise modulates hormones, amino acids, and neurotransmitters levels. In general, it seems that factors such as genes, gender, training status, and hormonal status need to be taken into account to gain a better understanding of the neuromodular underpinnings of aerobic exercise. More research using longitudinal studies and considering individual differences is necessary to determine actual benefits. We suggest that, in order to succeed, aerobic exercise programs should include optimal periodization, prevent overtraining and be tailored to interindividual differences, including neuro-developmental and genetically-based factors. PMID:26779053

  1. The Energetics of Aerobic versus Anaerobic Respiration.

    ERIC Educational Resources Information Center

    Champion, Timothy D.; Schwenz, Richard W.

    1990-01-01

    Background information, laboratory procedures, and a discussion of the results of an experiment designed to investigate the difference in energy gained from the aerobic and anaerobic oxidation of glucose are presented. Sample experimental and calculated data are included. (CW)

  2. Stabilisation of microalgae: Iodine mobilisation under aerobic and anaerobic conditions.

    PubMed

    Han, Wei; Clarke, William; Pratt, Steven

    2015-10-01

    Mobilisation of iodine during microalgae stabilisation was investigated, with the view of assessing the potential of stabilised microalgae as an iodine-rich fertiliser. An iodine-rich waste microalgae (0.35 ± 0.05 mg I g(-1) VS(added)) was stabilised under aerobic and anaerobic conditions. Iodine mobilisation was linearly correlated with carbon emission, indicating iodine was in the form of organoiodine. Comparison between iodine and nitrogen mobilisation relative to carbon emission indicated that these elements were, at least in part, housed separately within the cells. After stabilisation, there were 0.22 ± 0.05 and 0.19 ± 0.01 mg g(-1) VS(added) iodine remaining in the solid in the aerobic and anaerobic processed material respectively, meaning 38 ± 5.0% (aerobic) and 50 ± 8.6% (anaerobic) of the iodine were mobilised, and consequently lost from the material. The iodine content of the stabilised material is comparable to the iodine content of some seaweed fertilisers, and potentially satisfies an efficient I-fertilisation dose.

  3. Echinacea Supplementation: Does it Really Improve Aerobic Fitness?

    PubMed Central

    Baumann, Cory W.; Kwak, Dongmin

    2016-01-01

    [Purpose] Echinacea is an herbal supplement used by endurance athletes for its performance boosting properties. It is thought that Echinacea improves the blood’s oxygen carrying capacity by increasing production of erythropoietin (EPO), a glycoprotein that regulates red blood cell formation. Subsequently, these changes would lead to an overall improvement in maximal oxygen uptake (VO2max) and running economy (RE), two markers of aerobic fitness. The purpose of this review is to briefly discuss the physiological variables associated with distance running performance and how these variables are influenced by Echinacea supplementation. [Methods] To determine Echinacea’s ergogenic potential, human studies that used Echinacea in conjunction to analyzing the blood’s oxygen carrying capacity and/or aerobic fitness were assessed. [Results] Taken together, the majority of the published literature does not support the claim that Echinacea is a beneficial ergogenic aid. With the exception of one study, several independent groups have reported Echinacea supplementation does not increase EPO production, blood markers of oxygen transport, VO2max or RE in healthy untrained or trained subjects. [Conclusion] To date, the published literature does not support the use of Echinacea as an ergogenic aid to improve aerobic fitness in healthy untrained or trained subjects. PMID:27757381

  4. Surface Structure of Aerobically Oxidized Diamond Nanocrystals

    DTIC Science & Technology

    2014-10-27

    distribution is unlimited. Surface Structure of Aerobically Oxidized Diamond Nanocrystals The views, opinions and/or findings contained in this report...2211 diamond nanocrystals, REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 10. SPONSOR/MONITOR’S ACRONYM(S) ARO 8. PERFORMING...Room 254, Mail Code 8725 New York, NY 10027 -7922 ABSTRACT Surface Structure of Aerobically Oxidized Diamond Nanocrystals Report Title We investigate

  5. Aerobic biodegradation of selected monoterpenes.

    PubMed

    Misra, G; Pavlostathis, S G; Perdue, E M; Araujo, R

    1996-07-01

    Batch experiments were conducted to assess the biotransformation potential of four hydrocarbon monoterpenes (d-limonene, alpha-pinene, gamma-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and alpha-terpineol) under aerobic conditions at 23 degrees C. Both forest-soil extract and enriched cultures were used as inocula for the biodegradation experiments conducted first without, then with prior microbial acclimation to the monoterpenes tested. All four hydrocarbons and two alcohols were readily degraded. The increase in biomass and headspace CO2 concentrations paralleled the depletion of monoterpenes, thus confirming that terpene disappearance was the result of biodegradation accompanied by microbial growth and mineralization. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. A significant fraction of d-limonene-derived carbon was accounted for as non-extractable, dissolved organic carbon, whereas terpineol exhibited a much higher degree of utilization. The rate and extent of monoterpene biodegradation were not significantly affected by the presence of dissolved natural organic matter.

  6. Aerobic catabolism of bile acids.

    PubMed Central

    Leppik, R A; Park, R J; Smith, M G

    1982-01-01

    Seventy-eight stable cultures obtained by enrichment on media containing ox bile or a single bile acid were able to utilize one or more bile acids, as well as components of ox bile, as primary carbon sources for growth. All isolates were obligate aerobes, and most (70) were typical (48) or atypical (22) Pseudomonas strains, the remainder (8) being gram-positive actinomycetes. Of six Pseudomonas isolates selected for further study, five produced predominantly acidic catabolites after growth on glycocholic acid, but the sixth, Pseudomonas sp. ATCC 31752, accumulated as the principal product a neutral steroid catabolite. Optimum growth of Pseudomonas sp. ATCC 31752 on ox bile occurred at pH 7 to 8 and from 25 to 30 degrees C. No additional nutrients were required to sustain good growth, but growth was stimulated by the addition of ammonium sulfate and yeast extract. Good growth was obtained with a bile solids content of 40 g/liter in shaken flasks. A near-theoretical yield of neutral steroid catabolites, comprising a major (greater than 50%) and three minor products, was obtained from fermentor growth of ATCC 31752 in 6.7 g of ox bile solids per liter. The possible commercial exploitation of these findings to produce steroid drug intermediates for the pharmaceutical industry is discussed. PMID:7149711

  7. Proteome analysis of aerobic and fermentative metabolism in Rhizobium etli CE3.

    PubMed

    Encarnación, Sergio; Guzmán, Yudith; Dunn, Michael F; Hernández, Magdalena; del Carmen Vargas, Maria; Mora, Jaime

    2003-06-01

    Rhizobium etli undergoes a transition from an aerobic to a fermentative metabolism during successive subcultures in minimal medium. This metabolic transition does not occur in cells subcultured in rich medium, or in minimal medium containing either biotin or thiamine. In this report, we characterize the aerobic and fermentative metabolism of R. etli using proteome analysis. According to their synthesis patterns in response to aerobic (rich medium, minimal medium with biotin or minimal medium with thiamine) or fermentative (minimal medium without supplements) growth conditions, proteins were assigned to five different classes: (i) proteins produced only in aerobic conditions (e.g., catalase-peroxidase KatG and the E2 component of pyruvate dehydrogenase); (ii) protein produced under both conditions but strongly induced in aerobic metabolism (e.g., malate dehydrogenase and the succinyl-CoA synthetase beta subunit); (iii) proteins that were induced equally under all conditions tested (e.g., AniA, DnaK, and GroEL); (iv) proteins downregulated during aerobic metabolism, and (v) proteins specific to only one of the conditions analyzed. Northern blotting studies of katG expression confirmed the proteome data for this protein. The negative regulation of carbon metabolism proteins observed in fermentative metabolism is consistent with the drastic physiological changes which occur during this process.

  8. 1.7eV Al0.2Ga0.8As solar cells epitaxially grown on silicon by SSMBE using a superlattice and dislocation filters

    NASA Astrophysics Data System (ADS)

    Onno, Arthur; Wu, Jiang; Jiang, Qi; Chen, Siming; Tang, Mingchu; Maidaniuk, Yurii; Benamara, Mourad; Mazur, Yuriy I.; Salamo, Gregory J.; Harder, Nils-Peter; Oberbeck, Lars; Liu, Huiyin

    2016-03-01

    Lattice-mismatched 1.7eV Al0.2Ga0.8As photovoltaic solar cells have been monolithically grown on Si substrates using Solid Source Molecular Beam Epitaxy (SSMBE). As a consequence of the 4%-lattice-mismatch, threading dislocations (TDs) nucleate at the interface between the Si substrate and III-V epilayers and propagate to the active regions of the cell. There they act as recombination centers and degrade the performances of the cell. In our case, direct AlAs/GaAs superlattice growth coupled with InAlAs/AlAs strained layer superlattice (SLS) dislocation filter layers (DFLSs) have been used to reduce the TD density from 1×109cm-2 to 1(+/-0.2)×107cm-2. Lattice-matched Al0.2Ga0.8As cells have also been grown on GaAs as a reference. The best cell grown on silicon exhibits a Voc of 964mV, compared with a Voc of 1128mV on GaAs. Fill factors of respectively 77.6% and 80.2% have been calculated. Due to the lack of an anti-reflection coating and the non-optimized architecture of the devices, relatively low Jsc have been measured: 7.30mA.cm-2 on Si and 6.74mA.cm-2 on GaAs. The difference in short-circuit currents is believed to be caused by a difference of thickness between the samples due to discrepancies in the calibration of the MBE prior to each growth. The bandgap-voltage offset of the cells, defined as Eg/q-Voc, is relatively high on both substrates with 736mV measured on Si versus 572mV on GaAs. The non-negligible TD density partly explains this result on Si. On GaAs, non-ideal growth conditions are possibly responsible for these suboptimal performances.

  9. Aerobic degradation of mercaptosuccinate by the gram-negative bacterium Variovorax paradoxus strain B4.

    PubMed

    Carbajal-Rodríguez, Irma; Stöveken, Nadine; Satola, Barbara; Wübbeler, Jan Hendrik; Steinbüchel, Alexander

    2011-01-01

    The Gram-negative bacterium Variovorax paradoxus strain B4 was isolated from soil under mesophilic and aerobic conditions to elucidate the so far unknown catabolism of mercaptosuccinate (MS). During growth with MS this strain released significant amounts of sulfate into the medium. Tn5::mob-induced mutagenesis was successfully employed and yielded nine independent mutants incapable of using MS as a carbon source. In six of these mutants, Tn5::mob insertions were mapped in a putative gene encoding a molybdenum (Mo) cofactor biosynthesis protein (moeA). In two further mutants the Tn5::mob insertion was mapped in the gene coding for a putative molybdopterin (MPT) oxidoreductase. In contrast to the wild type, these eight mutants also showed no growth on taurine. In another mutant a gene putatively encoding a 3-hydroxyacyl-coenzyme A dehydrogenase (paaH2) was disrupted by transposon insertion. Upon subcellular fractionation of wild-type cells cultivated with MS as sole carbon and sulfur source, MPT oxidoreductase activity was detected in only the cytoplasmic fraction. Cells grown with succinate, taurine, or gluconate as a sole carbon source exhibited no activity or much lower activity. MPT oxidoreductase activity in the cytoplasmic fraction of the Tn5::mob-induced mutant Icr6 was 3-fold lower in comparison to the wild type. Therefore, a new pathway for MS catabolism in V. paradoxus strain B4 is proposed: (i) MPT oxidoreductase catalyzes the conversion of MS first into sulfinosuccinate (a putative organo-sulfur compound composed of succinate and a sulfino group) and then into sulfosuccinate by successive transfer of oxygen atoms, (ii) sulfosuccinate is cleaved into oxaloacetate and sulfite, and (iii) sulfite is oxidized to sulfate.

  10. Energy flux and osmoregulation of Saccharomyces cerevisiae grown in chemostats under NaCl stress.

    PubMed Central

    Olz, R; Larsson, K; Adler, L; Gustafsson, L

    1993-01-01

    The energetics and accumulation of solutes in Saccharomyces cerevisiae were investigated for cells grown aerobically in a chemostat under NaCl stress and glucose limitation. Changed energy requirements in relation to external salinity were examined by energy balance determinations performed by substrate and product analyses, with the latter including heat measurements by microcalorimetry. In both 0 and 0.9 M NaCl cultures, the catabolism was entirely respiratory at the lowest dilution rates tested but shifted to a mixed respiratory-fermentative metabolism at higher dilution rates. This shift occurred at a considerably lower dilution rate for salt-grown cells. The intracellular solute concentrations, as calculated on the basis of intracellular soluble space determinations, showed that the internal Na+ concentration increased from about 0.02 molal in basal medium to about 0.18 molal in 0.9 M NaCl medium, while intracellular K+ was maintained around 0.29 molal despite the variation in external salinity. The intracellular glycerol concentration increased from below 0.05 molal at low salinity to about 1.2 molal at 0.9 M NaCl. The concentrations of the internal solutes, however, changed insignificantly with growth rate and energy metabolism. The additional maintenance energy expenditure for growth at 0.9 M NaCl was, depending on the growth rate, 14 to 31% of the total energy requirement for growth at 0 M NaCl. Including the energy conserved in glycerol, the total additional energy demand for growth at 0.9 M NaCl corresponded to 28 to 51% of the energy required for growth at 0 M NaCl. Images PMID:8468281

  11. Marine oscillatoria (Trichodesmium): explanation for aerobic nitrogen fixation without heterocysts.

    PubMed

    Carpenter, E J; Price, C C

    1976-03-26

    Nitrogen fixation in marine Oscillatoria appears to be associated with differentiated cells located in the center of the colony. These central cells exhibit reduced pigmentation relative to peripherally located cells and do not incorporate 14CO2 in photosynthesis. Central cells apparently do not produce O2 which would deactivate nitrogenase. When central cells are exposed to O2 via disruption of the colonies, N2 fixation (acetylene reduction) decreases sharply even though individual trichomes remain intact. Disruption of colonies in the absence of O2 does not cause reduced nitrogenase activity. In the sea, turbulence from wave action apparently separates trichomes allowing O2 to enter thus decreasing nitrogenase activity. These observations explain how Oscillatoria is able to fix N2 without heterocysts in an aerobic environment and why it blooms virtually always occur in calm seas.

  12. Stimulation of Endomitotic DNA Synthesis and Cell Elongation by Gibberellic Acid in Epicotyls Grown from Gamma-irradiated Pea Seeds 1

    PubMed Central

    Callebaut, Alfons; Van Oostveldt, Patrick; Van Parijs, Roger

    1980-01-01

    Large doses of γ-irradiation, given to air-dried pea seeds, inhibit the endomitotic DNA synthesis in pea epicotyls during germination in darkness. The cortex cells of the etiolated epicotyls reach only the 4 C DNA level, whereas cortex cells of unirradiated seeds reach the 8 C DNA level. Epicotyl elongation and cell elongation are also reduced. Application of gibberellic acid restores the endomitotic DNA synthesis and the cell elongation in epicotyls of irradiated seeds. The cortex cells reach again the 8 C DNA level in darkness. The results suggest that γ-irradiation blocks endomitotic DNA synthesis and cell elongation by lowering the concentration of endogenous gibberellins. PMID:16661127

  13. Cyanide toxicity in hepatocytes under aerobic and anaerobic conditions.

    PubMed

    Aw, T Y; Jones, D P

    1989-09-01

    The effect of cyanide on cell viability and mitochondrial function was studied in hepatocytes exposed to air or argon. Cells were more susceptible to cyanide toxicity under air than under argon. Analysis of the disposition of cyanide showed that the difference in susceptibility to KCN was not due to O2-dependent differences in cyanide metabolism or elimination. Studies of mitochondrial function revealed that cyanide under aerobic conditions resulted in substantial swelling of the mitochondria, which corresponded to a matrix loading of phosphate. In addition, cyanide caused a loss of the mitochondrial protonmotive force. This was in contrast to the results for cells exposed to 30 min of anoxia alone in which there was no loss of mitochondrial delta pH, no detectable change in mitochondrial volume, and little matrix loading of phosphate. These results show that at least some of the protective mechanisms elicited by anoxia (B. S. Andersson, T. Y. Aw, and D. P. Jones. Am. J. Physiol. 252 (Cell Physiol. 21): C349-C355, 1987) are not elicited by cyanide alone. Thus cyanide under aerobic conditions does not provide a completely valid model for simple anoxia. Moreover, the results suggest that the molecular sensor necessary to signal suppression of metabolic and transport functions during neahypoxia is dependent on O2 and is neither stimulated nor antagonized by KCN.

  14. Aerobic Excercise and Research Opportunities to Benefit Impaired Children. (Project AEROBIC). Final Report.

    ERIC Educational Resources Information Center

    Idaho Univ., Moscow.

    The final report summarizes accomplishments of Project AEROBIC (Aerobic Exercise and Research Opportunities to Benefit Impaired Children), which provided a physical education exercise program for severely, profoundly, and multiply handicapped children aged 10-21. Activities are outlined for the 3 year period and include modification of exercise…

  15. Effect of long term anaerobic and intermittent anaerobic/aerobic starvation on aerobic granules.

    PubMed

    Pijuan, Maite; Werner, Ursula; Yuan, Zhiguo

    2009-08-01

    The effect of long term anaerobic and intermittent anaerobic/aerobic starvation on the structure and activity of aerobic granules was studied. Aerobic granular sludge treating abattoir wastewater and achieving high levels of nutrient removal was subjected to 4-5 week starvation under anaerobic and intermittent anaerobic/aerobic conditions. Microscopic pictures of granules at the beginning of the starvation period presented a round and compact surface morphology with a much defined external perimeter. Under both starvation conditions, the morphology changed at the end of starvation with the external border of the granules surrounded by floppy materials. The loss of granular compactness was faster and more pronounced under anaerobic/aerobic starvation conditions. The release of Ca(2+) at the onset of anaerobic/aerobic starvation suggests a degradation of extracellular polymeric substances. The activity of ammonia oxidizing bacteria was reduced by 20 and 36% during anaerobic and intermittent anaerobic/aerobic starvation, respectively. When fresh wastewater was reintroduced, the granules recovered their initial morphology within 1 week of normal operation and the nutrient removal activity recovered fully in 3 weeks. The results show that both anaerobic and intermittent anaerobic/aerobic conditions are suitable for maintaining granule structure and activity during starvation.

  16. Free amino acid and phenolic contents and antioxidative and cancer cell-inhibiting activities of extracts of 11 greenhouse-grown tomato varieties and 13 tomato-based foods.

    PubMed

    Choi, Suk-Hyun; Kim, Hyen-Ryung; Kim, Hyun-Jeong; Lee, In-Seon; Kozukue, Nobuyuki; Levin, Carol E; Friedman, Mendel

    2011-12-28

    Tomato (Solanum lycopersicum) plants synthesize nutrients, pigments, and bioactive compounds that benefit nutrition and human health. The nature and concentrations of these compounds are strongly influenced by varietal factors such as size and color as well as by processing. To better understand how these factors affect the concentration of nutrients and bioactive compounds, we analyzed 11 Korean tomato varieties grown under the same greenhouse conditions and 13 processed commercial tomato products for free amino acids and amino acid metabolites by HPLC, for individual phenolics by HPLC-MS, for total phenolics by the Folin-Ciocalteu method, for antioxidative activity by the FRAP and DPPH methods, and for cancer cell-inhibiting effects by the MTT assay. We also determined the protein content of the tomatoes by an automated Kjeldahl method. The results show that there is a broad range of bioactive compounds across tomato varieties and products. Small tomatoes had higher contents of bioactive compounds than the large ones. The content of phenolic compounds of processed products was lower than that of fresh tomatoes. Tomato extracts promoted growth in normal liver (Chang) cells, had little effect in normal lung (Hel299) cells, mildly inhibited growth of lung cancer (A549) cells, and first promoted and then, at higher concentrations, inhibited growth in lymphoma (U937) cells. The relationship of cell growth to measured constituents was not apparent. Dietary and health aspects of the results are discussed.

  17. Precision breeding for RNAi suppression of a major 4-coumarate:coenzyme A ligase gene improves cell wall saccharification from field grown sugarcane.

    PubMed

    Jung, Je Hyeong; Kannan, Baskaran; Dermawan, Hugo; Moxley, Geoffrey W; Altpeter, Fredy

    2016-11-01

    Sugarcane (Saccharum spp. hybrids) is a major feedstock for commercial bioethanol production. The recent integration of conversion technologies that utilize lignocellulosic sugarcane residues as well as sucrose from stem internodes has elevated bioethanol yields. RNAi suppression of lignin biosynthetic enzymes is a successful strategy to improve the saccharification of lignocellulosic biomass. 4-coumarate:coenzyme A ligase (4CL) is a key enzyme in the biosynthesis of phenylpropanoid metabolites, such as lignin and flavonoids. Identifying a major 4CL involved in lignin biosynthesis among multiple isoforms with functional divergence is key to manipulate lignin biosynthesis. In this study, two full length 4CL genes (Sh4CL1 and Sh4CL2) were isolated and characterized in sugarcane. Phylogenetic, expression and RNA interference (RNAi) analysis confirmed that Sh4CL1 is a major lignin biosynthetic gene. An intragenic precision breeding strategy may facilitate the regulatory approval of the genetically improved events and was used for RNAi suppression of Sh4CL1. Both, the RNAi inducing cassette and the expression cassette for the mutated ALS selection marker consisted entirely of DNA sequences from sugarcane or the sexually compatible species Sorghum bicolor. Field grown sugarcane with intragenic RNAi suppression of Sh4CL1 resulted in reduction of the total lignin content by up to 16.5 % along with altered monolignol ratios without reduction in biomass yield. Mature, field grown, intragenic sugarcane events displayed 52-76 % improved saccharification efficiency of lignocellulosic biomass compared to wild type (WT) controls. This demonstrates for the first time that an intragenic approach can add significant value to lignocellulosic feedstocks for biofuel and biochemical production.

  18. Protection against SR 4233 (tirapazamine) aerobic cytotoxicity by the metal chelators desferrioxamine and tiron

    SciTech Connect

    Herscher, L.L.; Krishna, M.C.; Cook, J.A.

    1994-11-15

    Metal chelating agents and antioxidants were evaluated as potential protectors against aerobic SR 4233 cytotoxicity in Chinese hamster V79 cells. The differential protection of aerobic and hypoxic cells by two metal chelators, desferrrioxamine and Tiron, is discussed in the context of their potential use in the on-going clinical trials with SR 4233. Cytotoxicity was evaluated using clonogenic assay. SR 4233 exposure was done in glass flasks as a function of time either alone or in the presence of the following agents: superoxide dismutase, catalase, 5,5-dimethyl-1-pyrroline, Trolox, ICRF-187, desferrioxamine, Tiron (1,2-dihydroxybenzene-3,5-disulfonate), and ascorbic acid. Experiments done under hypoxic conditions were carried out in specially designed glass flasks that were gassed with humidified nitrogen/carbon dioxide mixture and with a side-arm reservoir from which SR 4233 was added to cell media after hypoxia was obtained. Electron paramagnetic resonance studies were also performed. Electron paramagnetic resonance and spectrophotometry experiments suggest that under aerobic conditions SR 4233 undergoes futile redox cycling to produce superoxide. Treatment of cells during aerobic exposure to SR 4233 with the enzymes superoxide dismutase and catalase, the spin trapping agent DMPO, the water-soluble vitamin E analog Trolox, and the metal chelator ICRF-187 provided little or no protection against aerobic SR 4233 cytotoxicity. However, two other metal chelators, desferrioxamine and Tiron afforded significant protection against minimal protection to hypoxic cells treated with SR 4233. One potential mechanism of aerobic cytotoxicity is redox cycling of SR 4233 with molecular oxygen resulting in several potentially toxic oxidative species that overburden the intrinsic intracellular detoxification systems such as superoxide dismutase, catalase, and glutathione peroxidase. 23 refs., 4 figs., 1 tab.

  19. Aerobic Biofilms Grown from Athabasca Watershed Sediments Are Inhibited by Increasing Concentrations of Bituminous Compounds

    PubMed Central

    Lawrence, John R.; Sanschagrin, Sylvie; Roy, Julie L.; Swerhone, George D. W.; Korber, Darren R.; Greer, Charles W.

    2013-01-01

    Sediments from the Athabasca River and its tributaries naturally contain bitumen at various concentrations, but the impacts of this variation on the ecology of the river are unknown. Here, we used controlled rotating biofilm reactors in which we recirculated diluted sediments containing various concentrations of bituminous compounds taken from the Athabasca River and three tributaries. Biofilms exposed to sediments having low and high concentrations of bituminous compounds were compared. The latter were 29% thinner, had a different extracellular polysaccharide composition, 67% less bacterial biomass per μm2, 68% less cyanobacterial biomass per μm2, 64% less algal biomass per μm2, 13% fewer protozoa per cm2, were 21% less productive, and had a 33% reduced content in chlorophyll a per mm2 and a 20% reduction in the expression of photosynthetic genes, but they had a 23% increase in the expression of aromatic hydrocarbon degradation genes. Within the Bacteria, differences in community composition were also observed, with relatively more Alphaproteobacteria and Betaproteobacteria and less Cyanobacteria, Bacteroidetes, and Firmicutes in biofilms exposed to high concentrations of bituminous compounds. Altogether, our results suggest that biofilms that develop in the presence of higher concentrations of bituminous compounds are less productive and have lower biomass, linked to a decrease in the activities and abundance of photosynthetic organisms likely due to inhibitory effects. However, within this general inhibition, some specific microbial taxa and functional genes are stimulated because they are less sensitive to the inhibitory effects of bituminous compounds or can degrade and utilize some bitumen-associated compounds. PMID:24056457

  20. Investigation of crystallinity and planar defects in the Si nanowires grown by vapor-liquid-solid mode using indium catalyst for solar cell applications

    NASA Astrophysics Data System (ADS)

    Ajmal Khan, Muhammad; Ishikawa, Yasuaki; Kita, Ippei; Tani, Ayumi; Yano, Hiroshi; Fuyuki, Takashi; Konagai, Makoto

    2016-01-01

    Stacking-fault-free and planar defect (twinning plane)-free In-catalyzed Si nanowires (NWs) are essential for carrier transport and nanoscale device applications. In this article, In-catalyzed, vertically aligned, and cone-shaped Si NWs on Si(111) were grown successfully, in the vapor-liquid-solid (VLS) mode. In particular, the influences of substrate temperature (TS) and cooling rate (ΔTS/Δt) on the formation of planar defects, twinning planes along the [112] direction, and stacking faults in Si NWs were investigated. When TS was decreased from 600 °C to room temperature at a rate of 100 °C/240 s after Si NW growth, twinning plane defects perpendicular to the substrate and along different segments of (111)-oriented Si NWs were observed. Finally, one simple model was proposed to explain the stacking fault formation as well as Si NW length limitation due to the In-nanoparticle (In-NP) migration, and root causes of the twinning plane defects in the Si-NWs.

  1. Therapeutic aspects of aerobic dance participation.

    PubMed

    Estivill, M

    1995-01-01

    An ethnographic analysis of aerobic dance exercise culture was conducted to determine the impact of the culture on the mind-body connection. After a review of the predominant theories on the relationship between vigorous exercise and elevated mood, aerobic dance participants' experiences are reported to illustrate how cognitive experience and self-esteem may be influenced. Interviews revealed that some participants achieved a pleasantly altered state of consciousness and respite from depression and stress. The relationship of the work ethic to achievement of participant satisfaction is underscored.

  2. Comparative lipid composition of heterotrophically and autotrophically grown Sulfolobus acidocaldarius.

    PubMed

    Langworthy, T A

    1977-06-01

    Complex lipids from the thermoacidophilic facultative autotroph Sulfolobus acidocaldarius, as well as a strictly autotrophic isolate, were compared between cells grown on yeast extract and elemental sulfur. Lipids from both organisms grown autotrophically were nearly identical. Each contained about 15% neutral lipids, 35% glycolipids, and 50% acidic lipids. Glycolipids and acidic lipids contained C40H82-76-derived glycerol ether residues. Major glycolipids included the glycerol ether analogues of glucosyl galactosyl diglyceride (5%) and glucosyl polyol diglyceride (75%). Acidic lipids were comprised mainly of the glycerol ether analogues of phosphatidyl inositol (7%), inositolphosphoryl glucosyl polyol diglyceride (72%), and a partially characterized sulfate- and phosphate-containing derivative of glucosyl polyol diglyceride (13%). The lipids from cells grown heterotrophically were similar to those from autotrophically grown cells, except that the partially characterized acidic lipid was absent. In addition, the two glycolipids as well as the respective inositolphosphoryl derivatives were each present in nearly equal proportions.

  3. Comparative lipid composition of heterotrophically and autotrophically grown Sulfolobus acidocaldarius.

    PubMed Central

    Langworthy, T A

    1977-01-01

    Complex lipids from the thermoacidophilic facultative autotroph Sulfolobus acidocaldarius, as well as a strictly autotrophic isolate, were compared between cells grown on yeast extract and elemental sulfur. Lipids from both organisms grown autotrophically were nearly identical. Each contained about 15% neutral lipids, 35% glycolipids, and 50% acidic lipids. Glycolipids and acidic lipids contained C40H82-76-derived glycerol ether residues. Major glycolipids included the glycerol ether analogues of glucosyl galactosyl diglyceride (5%) and glucosyl polyol diglyceride (75%). Acidic lipids were comprised mainly of the glycerol ether analogues of phosphatidyl inositol (7%), inositolphosphoryl glucosyl polyol diglyceride (72%), and a partially characterized sulfate- and phosphate-containing derivative of glucosyl polyol diglyceride (13%). The lipids from cells grown heterotrophically were similar to those from autotrophically grown cells, except that the partially characterized acidic lipid was absent. In addition, the two glycolipids as well as the respective inositolphosphoryl derivatives were each present in nearly equal proportions. Images PMID:863856

  4. Sustained high-yield production of recombinant proteins in transiently transfected COS-7 cells grown on trimethylamine-coated (hillex) microcarrier beads.

    PubMed

    Knibbs, Randall N; Dame, Michael; Allen, Melissa R; Ding, Yunhong; Hillegas, William J; Varani, James; Stoolman, Lloyd M

    2003-01-01

    The present study shows that COS-7 cells transiently transfected and maintained on positively charged (trimethylamine-coated) microcarrier beads synthesize recombinant protein at higher levels and for longer periods of time than cells transfected and maintained on polystyrene flasks in monolayer culture. Sustained, high-level synthesis was observed with secreted chimeric proteins (murine E-selectin- and P-selectin-human IgM chimeras) and a secreted hematopoietic growth factor (granulocyte-macrophage colony-stimulating factor). Studies with green fluorescent protein indicated that the transfected cells attached more firmly to the trimethylamine-coated microcarriers than to polystyrene flasks. After 10-14 days in culture, most of the transfected cells detached from the surface of the polystyrene flasks, whereas most transfected cells remained attached to the microcarriers. The transiently transfected microcarrier cultures produced higher levels of protein per transfected cell due to this prolonged attachment. The prolonged attachment and higher output of transfected cells on microcarriers resulted in a 5-fold increase in protein production from a single transfection over two weeks. Thus, microcarrier-based transient transfection yields quantities of recombinant proteins with a significant savings of time and reagents over monolayer culture.

  5. Effect of 8 MeV electron irradiation on the performance of CSS grown CdTe/CdS solar cells

    NASA Astrophysics Data System (ADS)

    Krishnan, Sheeja; Sanjeev, Ganesh; Pattabi, Manjunatha; Ullal, Harin S.; Wu, Xuanzhi

    2007-12-01

    The results of investigations carried out on the effect of electron irradiation on the electrical properties of CdTe/CdS solar cells prepared by close spaced sublimation (CSS) are presented in this paper. The solar cells were characterized using current-voltage (I-V) measurements under dark and air mass (AM) 1.5 illumination conditions. They were also characterized by capacitance measurements at various frequencies. The cells were exposed to graded doses of electrons up to 100 kGy. The effect of electron irradiation on the solar cell parameters such as short circuit current (Isc), open circuit voltage (Voc), fill factor (FF), conversion efficiency (η), saturation current (Io) and ideality factor (n) were studied. Only small changes in the cell parameters were observed after electron irradiation. Since the observed changes in the cell parameters were not remarkable up to an electron dose of 100 kGy, CdTe/CdS solar cells seem to be stable under electron irradiation.

  6. Pachytene spermatocyte protein(s) stimulate Sertoli cells grown in bicameral chambers: dose-dependent secretion of ceruloplasmin, sulfated glycoprotein-1, sulfated glycoprotein-2, and transferrin.

    PubMed

    Onoda, M; Djakiew, D

    1991-03-01

    Interactions between pachytene spermatocytes and Sertoli cells were investigated using the bicameral culture chamber system. Pachytene spermatocytes were isolated from adult rats with a purity in excess of 90% by centrifugal elutriation. The pachytene spermatocytes were cultured in a defined media and pachytene spermatocyte protein prepared from the conditioned media by dialysis and lyophilization. This pachytene spermatocyte protein was reconstituted at various concentrations and incubated with confluent epithelial sheets of immature Sertoli cells cultured in bicameral chambers. Pachytene spermatocyte protein stimulated secretion of total [35S]methionine-labeled protein from Sertoli cells in a dose-dependent manner predominantly in an apical direction. This stimulatory effect of pachytene spermatocyte protein was domain specific from the apical surface of Sertoli cells, and seemed specific for secretion because total intracellular protein did not increase under the influence of pachytene spermatocyte protein. Pachytene spermatocyte protein and follicle-stimulating hormone additively stimulated Sertoli cell secretion. The physicochemical characteristics of the stimulatory pachytene spermatocyte protein are indicative of heat stability, whereas the stimulatory pachytene spermatocyte protein exhibit acid, dithiothreitol and trypsin sensitivity, and partial urea sensitivity. Furthermore, Sertoli cell secretion of ceruloplasmin, sulfated glycoprotein-1, sulfated glycoprotein-2, and transferrin in response to various concentrations of pachytene spermatocyte protein were determined by immunoprecipitate of these [35S]methionine-labeled proteins with polyclonal antibodies. Maximal stimulation of ceruloplasmin and sulfated glycoprotein-1 secretion from Sertoli cells was observed at a dose of 50 micrograms/ml pachytene spermatocyte protein, whereas maximal stimulation of sulfated glycoprotein-2 and transferrin secretion from Sertoli cells was observed at a dose of 100

  7. ANAEROBIC AND AEROBIC TREATMENT OF CHLORINATED ALIPHATIC COMPOUNDS

    EPA Science Inventory

    Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). Glucose,...

  8. Aerobic glycolysis tunes YAP/TAZ transcriptional activity

    PubMed Central

    Enzo, Elena; Santinon, Giulia; Pocaterra, Arianna; Aragona, Mariaceleste; Bresolin, Silvia; Forcato, Mattia; Grifoni, Daniela; Pession, Annalisa; Zanconato, Francesca; Guzzo, Giulia; Bicciato, Silvio; Dupont, Sirio

    2015-01-01

    Increased glucose metabolism and reprogramming toward aerobic glycolysis are a hallmark of cancer cells, meeting their metabolic needs for sustained cell proliferation. Metabolic reprogramming is usually considered as a downstream consequence of tumor development and oncogene activation; growing evidence indicates, however, that metabolism on its turn can support oncogenic signaling to foster tumor malignancy. Here, we explored how glucose metabolism regulates gene transcription and found an unexpected link with YAP/TAZ, key transcription factors regulating organ growth, tumor cell proliferation and aggressiveness. When cells actively incorporate glucose and route it through glycolysis, YAP/TAZ are fully active; when glucose metabolism is blocked, or glycolysis is reduced, YAP/TAZ transcriptional activity is decreased. Accordingly, glycolysis is required to sustain YAP/TAZ pro-tumorigenic functions, and YAP/TAZ are required for the full deployment of glucose growth-promoting activity. Mechanistically we found that phosphofructokinase (PFK1), the enzyme regulating the first committed step of glycolysis, binds the YAP/TAZ transcriptional cofactors TEADs and promotes their functional and biochemical cooperation with YAP/TAZ. Strikingly, this regulation is conserved in Drosophila, where phosphofructokinase is required for tissue overgrowth promoted by Yki, the fly homologue of YAP. Moreover, gene expression regulated by glucose metabolism in breast cancer cells is strongly associated in a large dataset of primary human mammary tumors with YAP/TAZ activation and with the progression toward more advanced and malignant stages. These findings suggest that aerobic glycolysis endows cancer cells with particular metabolic properties and at the same time sustains transcription factors with potent pro-tumorigenic activities such as YAP/TAZ. PMID:25796446

  9. Aerobic glycolysis tunes YAP/TAZ transcriptional activity.

    PubMed

    Enzo, Elena; Santinon, Giulia; Pocaterra, Arianna; Aragona, Mariaceleste; Bresolin, Silvia; Forcato, Mattia; Grifoni, Daniela; Pession, Annalisa; Zanconato, Francesca; Guzzo, Giulia; Bicciato, Silvio; Dupont, Sirio

    2015-05-12

    Increased glucose metabolism and reprogramming toward aerobic glycolysis are a hallmark of cancer cells, meeting their metabolic needs for sustained cell proliferation. Metabolic reprogramming is usually considered as a downstream consequence of tumor development and oncogene activation; growing evidence indicates, however, that metabolism on its turn can support oncogenic signaling to foster tumor malignancy. Here, we explored how glucose metabolism regulates gene transcription and found an unexpected link with YAP/TAZ, key transcription factors regulating organ growth, tumor cell proliferation and aggressiveness. When cells actively incorporate glucose and route it through glycolysis, YAP/TAZ are fully active; when glucose metabolism is blocked, or glycolysis is reduced, YAP/TAZ transcriptional activity is decreased. Accordingly, glycolysis is required to sustain YAP/TAZ pro-tumorigenic functions, and YAP/TAZ are required for the full deployment of glucose growth-promoting activity. Mechanistically we found that phosphofructokinase (PFK1), the enzyme regulating the first committed step of glycolysis, binds the YAP/TAZ transcriptional cofactors TEADs and promotes their functional and biochemical cooperation with YAP/TAZ. Strikingly, this regulation is conserved in Drosophila, where phosphofructokinase is required for tissue overgrowth promoted by Yki, the fly homologue of YAP. Moreover, gene expression regulated by glucose metabolism in breast cancer cells is strongly associated in a large dataset of primary human mammary tumors with YAP/TAZ activation and with the progression toward more advanced and malignant stages. These findings suggest that aerobic glycolysis endows cancer cells with particular metabolic properties and at the same time sustains transcription factors with potent pro-tumorigenic activities such as YAP/TAZ.

  10. Efficiency enhancement of TiO2 (active material) solar cell by inserting copper particles grown with pulse voltage electroplating method

    NASA Astrophysics Data System (ADS)

    Rokhmat, Mamat; Sutisna; Wibowo, Edy; Khairurrijal; Abdullah, Mikrajuddin

    2017-01-01

    Here, we report the manufacture of a solar cell using TiO2 nanoparticles as photon absorbers and copper bridges inserted between the TiO2 particles. The copper bridges were synthesized by the pulse voltage electroplating method, and the effect of the pulse duty cycle was explored. The amount of copper deposited between TiO2 particles can be controlled by varying the duty cycles and the deposition time. We found that the cell fabricated by the deposition of copper at duty cycles of 60% and a deposition time of 30 s exhibited the highest efficiency (2.21%). Efficiency was improved to 3.5% following the post-treatment of the cell with NaOH. We also proposed a simple mathematical model to explain the dependence of the efficiency on the amount of copper. Efficiencies of more than 3% for solar cells made by a simple method and using inexpensive materials make these solar cells promising competition for the current commercial solar cells.

  11. Compartment model of aerobic and anaerobic biodegradation in a municipal solid waste landfill.

    PubMed

    Kim, Sang-Yul; Tojo, Yasumasa; Matsuto, Toshihiko

    2007-12-01

    The mathematical formulations in a one-dimensional compartment model of the biodegradation of organic landfill components are described. The model is designed to switch between anaerobic and aerobic conditions, depending on the local oxygen concentration. The model also includes the effect of environmental factors, such as moisture content, pH, and temperature, on reaction rates. The model includes not only biodegradation processes for carbon compounds (acetate, CO2, CH4), but also for nitrogen compounds involved in nitrification and denitrification due to their significance in landfills. Two example runs to simulate anaerobic and aerobic waste were conducted for a single landfill unit cell by changing the organic content and diffusion coefficient.

  12. Prostate tumor grown in NASA Bioreactor

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This prostate cancer construct was grown during NASA-sponsored bioreactor studies on Earth. Cells are attached to a biodegradable plastic lattice that gives them a head start in growth. Prostate tumor cells are to be grown in a NASA-sponsored Bioreactor experiment aboard the STS-107 Research-1 mission in 2002. Dr. Leland Chung of the University of Virginia is the principal investigator. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Credit: NASA and the University of Virginia.

  13. Anaerobic and aerobic degradation of pyridine by a newly isolated denitrifying bacterium.

    PubMed Central

    Rhee, S K; Lee, G M; Yoon, J H; Park, Y H; Bae, H S; Lee, S T

    1997-01-01

    New denitrifying bacteria that could degrade pyridine under both aerobic and anaerobic conditions were isolated from industrial wastewater. The successful enrichment and isolation of these strains required selenite as a trace element. These isolates appeared to be closely related to Azoarcus species according to the results of 16S rRNA sequence analysis. An isolated strain, pF6, metabolized pyridine through the same pathway under both aerobic and anaerobic conditions. Since pyridine induced NAD-linked glutarate-dialdehyde dehydrogenase and isocitratase activities, it is likely that the mechanism of pyridine degradation in strain pF6 involves N-C-2 ring cleavage. Strain pF6 could degrade pyridine in the presence of nitrate, nitrite, and nitrous oxide as electron acceptors. In a batch culture with 6 mM nitrate, degradation of pyridine and denitrification were not sensitively affected by the redox potential, which gradually decreased from 150 to -200 mV. In a batch culture with the nitrate concentration higher than 6 mM, nitrite transiently accumulated during denitrification significantly inhibited cell growth and pyridine degradation. Growth yield on pyridine decreased slightly under denitrifying conditions from that under aerobic conditions. Furthermore, when the pyridine concentration used was above 12 mM, the specific growth rate under denitrifying conditions was higher than that under aerobic conditions. Considering these characteristics, a newly isolated denitrifying bacterium, strain pF6, has advantages over strictly aerobic bacteria in field applications. PMID:9212408

  14. Aggression is associated with aerobic glycolysis in the honey bee brain(1).

    PubMed

    Chandrasekaran, S; Rittschof, C C; Djukovic, D; Gu, H; Raftery, D; Price, N D; Robinson, G E

    2015-02-01

    Aerobic glycolysis involves increased glycolysis and decreased oxidative catabolism of glucose even in the presence of an ample oxygen supply. Aerobic glycolysis, a common metabolic pattern in cancer cells, was recently discovered in both the healthy and diseased human brain, but its functional significance is not understood. This metabolic pattern in the brain is surprising because it results in decreased efficiency of adenosine triphosphate (ATP) production in a tissue with high energetic demands. We report that highly aggressive honey bees (Apis mellifera) show a brain transcriptomic and metabolic state consistent with aerobic glycolysis, i.e. increased glycolysis in combination with decreased oxidative phosphorylation. Furthermore, exposure to alarm pheromone, which provokes aggression, causes a metabolic shift to aerobic glycolysis in the bee brain. We hypothesize that this metabolic state, which is associated with altered neurotransmitter levels, increased glycolytically derived ATP and a reduced cellular redox state, may lead to increased neuronal excitability and oxidative stress in the brain. Our analysis provides evidence for a robust, distinct and persistent brain metabolic response to aggression-inducing social cues. This finding for the first time associates aerobic glycolysis with naturally occurring behavioral plasticity, which has important implications for understanding both healthy and diseased brain function.

  15. Aggression is associated with aerobic glycolysis in the honey bee brain1

    PubMed Central

    Chandrasekaran, S.; Rittschof, C. C.; Djukovic, D.; Gu, H.; Raftery, D.; Price, N. D.; Robinson, G. E.

    2015-01-01

    Aerobic glycolysis involves increased glycolysis and decreased oxidative catabolism of glucose even in the presence of an ample oxygen supply. Aerobic glycolysis, a common metabolic pattern in cancer cells, was recently discovered in both the healthy and diseased human brain, but its functional significance is not understood. This metabolic pattern in the brain is surprising because it results in decreased efficiency of adenosine triphosphate (ATP) production in a tissue with high energetic demands. We report that highly aggressive honey bees (Apis mellifera) show a brain transcriptomic and metabolic state consistent with aerobic glycolysis, i.e. increased glycolysis in combination with decreased oxidative phosphorylation. Furthermore, exposure to alarm pheromone, which provokes aggression, causes a metabolic shift to aerobic glycolysis in the bee brain. We hypothesize that this metabolic state, which is associated with altered neurotransmitter levels, increased glycolytically derived ATP and a reduced cellular redox state, may lead to increased neuronal excitability and oxidative stress in the brain. Our analysis provides evidence for a robust, distinct and persistent brain metabolic response to aggression-inducing social cues. This finding for the first time associates aerobic glycolysis with naturally occurring behavioral plasticity, which has important implications for understanding both healthy and diseased brain function. PMID:25640316

  16. Anaerobic and aerobic transformation of TNT

    SciTech Connect

    Kulpa, C.F.; Boopathy, R.; Manning, J.

    1996-12-31

    Most studies on the microbial metabolism of nitroaromatic compounds have used pure cultures of aerobic microorganisms. In many cases, attempts to degrade nitroaromatics under aerobic conditions by pure cultures result in no mineralization and only superficial modifications of the structure. However, mixed culture systems properly operated result in the transformation of 2,4,6-trinitrotoluene (TNT) and in some cases mineralization of TNT occurs. In this paper, the mixed culture system is described with emphasis on intermediates and the characteristics of the aerobic microbial process including the necessity for a co-substrate. The possibility of removing TNT under aerobic/anoxic conditions is described in detail. Another option for the biodegradation of TNT and nitroaromatics is under anaerobic, sulfate reducing conditions. In this instance, the nitroaromatic compounds undergo a series of reductions with the formation of amino compounds. TNT under sulfate reducing conditions is reduced to triaminotoluene presumably by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of nitro groups from TNT is achieved by a series of reductive reactions with the formation of ammonia and toluene by Desulfovibrio sp. (B strain). These metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. The data supporting the anaerobic transformation of TNT under different growth condition are reviewed in this report.

  17. Aerobic Exercise Prescription for Rheumatoid Arthritics.

    ERIC Educational Resources Information Center

    Evans, Blanche W.; Williams, Hilda L.

    The use of exercise as a general treatment for rheumatoid arthritics (RA) has included range of motion, muscular strength, water exercise and rest therapy while virtually ignoring possible benefits of aerobic exercise. The purposes of this project were to examine the guidelines for exercise prescription in relation to this special population and…

  18. Reflections on Psychotherapy and Aerobic Exercise.

    ERIC Educational Resources Information Center

    Silverman, Wade

    This document provides a series of reflections by a practicing psychologist on the uses of aerobic workouts in psychotherapy. Two case histories are cited to illustrate the contention that the mode of exercise, rather than simply its presence or absence, is the significant indicator of a patient's emotional well-being or psychopathology. The first…

  19. AEROBIC DENITRIFICATION: IMPLICATIONS FOR NITROGEN FATE MODELING

    EPA Science Inventory

    In the Mississippi, as well as most nitrogen-degraded rivers and streams, NO3- is the dominant N species and therefore understanding its biogeochemical behavior is critical for accurate nitrogen fate modeling. To our knowledge this is the first work to report aerobic denitrificat...

  20. Aerobic exercise in fibromyalgia: a practical review.

    PubMed

    Thomas, Eric N; Blotman, Francis

    2010-07-01

    The objective of the study was to determine the current evidence to support guidelines for aerobic exercise (AE) and fibromyalgia (FM) in practice, and to outline specific research needs in these areas. Data sources consisted of a PubMed search, 2007 Cochrane Data Base Systematic review, 2008 Ottawa panel evidence-based clinical practice guidelines, as well as additional references found from the initial search. Study selection included randomized clinical trials that compared an aerobic-only exercise intervention (land or pool based) with an untreated control, a non-exercise intervention or other exercise programs in patients responding to the 1990 American College of Rheumatology criteria for FM. The following outcome data were obtained: pain, tender points, perceived improvement in FM symptoms such as the Fibromyalgia Impact Questionnaire total score (FIQ), physical function, depression (e.g., Beck Depression Inventory, FIQ subscale for depression), fatigue and sleep were extracted from 19 clinical trials that considered the effects of aerobic-only exercise in FM patients. Data synthesis shows that there is moderate evidence of important benefit of aerobic-only exercise in FM on physical function and possibly on tender points and pain. It appears to be sufficient evidence to support the practice of AE as a part of the multidisciplinary management of FM. However, future studies must be more adequately sized, homogeneously assessed, and monitored for adherence, to draw definitive conclusions.

  1. Media for the aerobic growth of campylobacter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of agar and sodium bicarbonate (NaHCO3) concentration on aerobic growth of Campylobacter in a fumarate-pyruvate medium was examined. The broth medium was supplemented with 0.0 to 0.2% agar and inoculated with 106 CFU/ml of Campylobacter coli 33559, Campylobacter fetus 27349, Campylobacter...

  2. Ligament Tissue Engineering Using a Novel Porous Polycaprolactone Fumarate Scaffold and Adipose Tissue-Derived Mesenchymal Stem Cells Grown in Platelet Lysate

    PubMed Central

    Wagner, Eric R.; Bravo, Dalibel; Dadsetan, Mahrokh; Riester, Scott M.; Chase, Steven; Westendorf, Jennifer J.; Dietz, Allan B.; van Wijnen, Andre J.; Yaszemski, Michael J.

    2015-01-01

    Purpose: Surgical reconstruction of intra-articular ligament injuries is hampered by the poor regenerative potential of the tissue. We hypothesized that a novel composite polymer “neoligament” seeded with progenitor cells and growth factors would be effective in regenerating native ligamentous tissue. Methods: We synthesized a fumarate-derivative of polycaprolactone fumarate (PCLF) to create macro-porous scaffolds to allow cell–cell communication and nutrient flow. Clinical grade human adipose tissue-derived human mesenchymal stem cells (AMSCs) were cultured in 5% human platelet lysate (PL) and seeded on scaffolds using a dynamic bioreactor. Cell growth, viability, and differentiation were examined using metabolic assays and immunostaining for ligament-related markers (e.g., glycosaminoglycans [GAGs], alkaline phosphatase [ALP], collagens, and tenascin-C). Results: AMSCs seeded on three-dimensional (3D) PCLF scaffolds remain viable for at least 2 weeks with proliferating cells filling the pores. AMSC proliferation rates increased in PL compared to fetal bovine serum (FBS) (p < 0.05). Cells had a low baseline expression of ALP and GAG, but increased expression of total collagen when induced by the ligament and tenogenic growth factor fibroblast growth factor 2 (FGF-2), especially when cultured in the presence of PL (p < 0.01) instead of FBS (p < 0.05). FGF-2 and PL also significantly increased immunostaining of tenascin-C and collagen at 2 and 4 weeks compared with human fibroblasts. Summary: Our results demonstrate that AMSCs proliferate and eventually produce a collagen-rich extracellular matrix on porous PCLF scaffolds. This novel scaffold has potential in stem cell engineering and ligament regeneration. PMID:26413793

  3. PTH Promotes Bone Anabolism by Stimulating Aerobic Glycolysis via IGF Signaling.

    PubMed

    Esen, Emel; Lee, Seung-Yon; Wice, Burton M; Long, Fanxin

    2015-11-01

    Teriparatide, a recombinant peptide corresponding to amino acids 1-34 of human parathyroid hormone (PTH), has been an effective bone anabolic drug for over a decade. However, the mechanism whereby PTH stimulates bone formation remains incompletely understood. Here we report that in cultures of osteoblast-lineage cells, PTH stimulates glucose consumption and lactate production in the presence of oxygen, a hallmark of aerobic glycolysis, also known as Warburg effect. Experiments with radioactively labeled glucose demonstrate that PTH suppresses glucose entry into the tricarboxylic acid cycle (TCA cycle). Mechanistically, the increase in aerobic glycolysis is secondary to insulin-like growth factor (Igf) signaling induced by PTH, whereas the metabolic effect of Igf is dependent on activation of mammalian target of rapamycin complex 2 (mTORC2). Importantly, pharmacological perturbation of glycolysis suppresses the bone anabolic effect of intermittent PTH in the mouse. Thus, stimulation of aerobic glycolysis via Igf signaling contributes to bone anabolism in response to PTH.

  4. Adolescents' Interest and Performances in Aerobic Fitness Testing

    ERIC Educational Resources Information Center

    Zhu, Xihe; Chen, Senlin; Parrott, James

    2014-01-01

    This study examined adolescents' interest in aerobic fitness testing and its relation to the test performances. Adolescents (N = 356) from three middle schools participated in the study. The participants took two aerobic fitness tests: the Progressive Aerobic Cardiovascular Endurance Run (PACER) and One-Mile Run (1MR) with a two-day interval, and…

  5. Ventilation and Speech Characteristics during Submaximal Aerobic Exercise

    ERIC Educational Resources Information Center

    Baker, Susan E.; Hipp, Jenny; Alessio, Helaine

    2008-01-01

    Purpose: This study examined alterations in ventilation and speech characteristics as well as perceived dyspnea during submaximal aerobic exercise tasks. Method: Twelve healthy participants completed aerobic exercise-only and simultaneous speaking and aerobic exercise tasks at 50% and 75% of their maximum oxygen consumption (VO[subscript 2] max).…

  6. What is the influence of ordinary epidermal cells and stomata on the leaf plasticity of coffee plants grown under full-sun and shady conditions?

    PubMed

    Pompelli, M F; Martins, S C V; Celin, E F; Ventrella, M C; Damatta, F M

    2010-11-01

    Stomata are crucial in land plant productivity and survival. In general, with lower irradiance, stomatal and epidermal cell frequency per unit leaf area decreases, whereas guard-cell length or width increases. Nevertheless, the stomatal index is accepted as remaining constant. The aim of this paper to study the influence of ordinary epidermal cells and stomata on leaf plasticity and the influence of these characteristics on stomata density, index, and sizes, in the total number of stomata, as well as the detailed distribution of stomata on a leaf blade. As a result, a highly significant positive correlation (R²(a) = 0.767 p ≤ 0.001) between stomatal index and stomatal density, and with ordinary epidermal cell density (R²(a) = 0.500 p ≤ 0.05), and a highly negative correlation between stomatal index and ordinary epidermal cell area (R²(a) = -0.571 p ≤ 0.001), were obtained. However in no instance was the correlation between stomatal index or stomatal density and stomatal dimensions taken into consideration. The study also indicated that in coffee, the stomatal index was 19.09% in shaded leaves and 20.08% in full-sun leaves. In this sense, variations in the stomatal index by irradiance, its causes and the consequences on plant physiology were discussed.

  7. A comparison of the response of two Burkholderia fungorum strains grown as planktonic cells versus biofilm to dibenzothiophene and select polycyclic aromatic hydrocarbons.

    PubMed

    Khoei, Nazanin Seyed; Andreolli, Marco; Lampis, Silvia; Vallini, Giovanni; Turner, Raymond J

    2016-10-01

    In natural environments, bacteria often exist in close association with surfaces and interfaces by establishing biofilms. Here, we report on the ability of Burkholderia fungorum strains DBT1 and 95 to survive in high concentrations of hydrocarbons, and we compare their growth as a biofilm vs. planktonic cells. The 2 compounds tested were dibenzothiophene (DBT) and a mixture of naphthalene, phenanthrene, and pyrene (5:2:1) as representative compounds of thiophenes and polycyclic aromatic hydrocarbons (PAHs), respectively. The results showed that both strains were able to degrade DBT and to survive in the presence of up to a 2000 mg·L(-1) concentration of this compound both as a biofilm and as free-living cells. Moreover, B. fungorum DBT1 showed reduced tolerance towards the mixed PAHs (2000 mg·L(-1) naphthalene, 800 mg·L(-1) phenanthrene, and 400 mg·L(-1) pyrene) both as a biofilm and as free-living cells. Conversely, biofilms of B. fungorum 95 enhanced resistance against these toxic compounds compared with planktonic cells (P < 0.05). Visual observation through confocal laser scanning microscopy showed that exposure of biofilms to DBT and PAHs altered their structure: high concentrations of DBT triggered an aggregation of biofilm cells. These findings provide new perspectives on the effectiveness of using DBT-degrading bacterial strains in bioremediation of hydrocarbon-contaminated sites.

  8. 17β-Hydroxy-18-acetoxywithanolides from Aeroponically Grown Physalis crassifolia and Their Potent and Selective Cytotoxicity for Prostate Cancer Cells.

    PubMed

    Xu, Ya-ming; Bunting, Daniel P; Liu, Manping X; Bandaranayake, Hema A; Gunatilaka, A A Leslie

    2016-04-22

    When cultivated under aeroponic growth conditions, Physalis crassifolia produced 11 new withanolides (1-11) and seven known withanolides (12-18) including those obtained from the wild-crafted plant. The structures of the new withanolides were elucidated by the application of spectroscopic techniques, and the known withanolides were identified by comparison of their spectroscopic data with those reported. Withanolides 1-11 and 16 were evaluated for their potential anticancer activity using five tumor cell lines. Of these, the 17β-hydroxy-18-acetoxywithanolides 1, 2, 6, 7, and 16 showed potent antiproliferative activity, with some having selectivity for prostate adenocarcinoma (LNCaP and PC-3M) compared to the breast adenocarcinoma (MCF-7), non-small-cell lung cancer (NCI-H460), and CNS glioma (SF-268) cell lines used. The cytotoxicity data obtained for 12-15, 17, and 19 have provided additional structure-activity relationship information for the 17β-hydroxy-18-acetoxywithanolides.

  9. High-efficiency screen-printed solar cell on edge-defined film-fed grown ribbon silicon through optimized rapid belt co-firing of contacts and high-sheet-resistance emitter

    NASA Astrophysics Data System (ADS)

    Rohatgi, Ajeet; Hilali, Mohamed M.; Nakayashiki, Kenta

    2004-04-01

    High-quality screen-printed contacts were achieved on a high-sheet-resistance emitter (˜100 Ω/sq.) using PV168 Ag paste and rapid co-firing in the belt furnace. The optimized co-firing cycle developed for a 100 Ω/sq. emitter produced 16.1% efficient 4 cm2 planar edge-defined film-fed grown (EFG) ribbon Si cells with a low series-resistance (0.8 Ω cm2), high fill factor of ˜0.77, along with very significant bulk lifetime enhancement from 3 to 100 μs. This represents the highest-efficiency screen-printed EFG Si cells with single-layer antireflection (AR) coating. These cells were fabricated using a simple process involving POCl3 diffusion for a high-sheet-resistance emitter, SiNx AR coating and rapid cofiring of Ag grid and Al-doped back-surface field in a conventional belt furnace. The rapid cofiring process also prevented junction shunting while maintaining very effective SiNx-induced hydrogen passivation of defects, resulting in an average bulk lifetime exceeding 100 μs.

  10. Aerobic exercise training in modulation of aerobic physical fitness and balance of burned patients.

    PubMed

    Ali, Zizi M Ibrahim; El-Refay, Basant H; Ali, Rania Reffat

    2015-03-01

    [Purpose] This study aimed to determine the impact of aerobic exercise on aerobic capacity, balance, and treadmill time in patients with thermal burn injury. [Subjects and Methods] Burned adult patients, aged 20-40 years (n=30), from both sexes, with second degree thermal burn injuries covering 20-40% of the total body surface area (TBSA), were enrolled in this trial for 3 months. Patients were randomly divided into; group A (n=15), which performed an aerobic exercise program 3 days/week for 60 min and participated in a traditional physical therapy program, and group B (n=15), which only participated in a traditional exercise program 3 days/week. Maximal aerobic capacity, treadmill time, and Berg balance scale were measured before and after the study. [Results] In both groups, the results revealed significant improvements after treatment in all measurements; however, the improvement in group A was superior to that in group B. [Conclusion] The results provide evidence that aerobic exercises for adults with healed burn injuries improve aerobic physical fitness and balance.

  11. Transwell-grown HepG2 cell monolayers as in vitro permeability model to study drug-drug or drug-food interactions.

    PubMed

    Berginc, Katja; Kristl, Albin

    2011-01-01

    HepG2 cell monolayers, formed during cell growth on collagen-coated Transwell® (Corning® Inc., Corning, NY, USA) inserts, can be used for the evaluation of interactions between food supplements and drugs that are substrates for P-glycoprotein (Pgp) and/or multidrug resistance-associated protein 2 (MRP-2). Samples obtained during such permeability studies were relatively free of intracellular proteins or cell debris compared to usually performed uptake experiments with HepG2 cells; therefore no special preparation protocol prior to the analysis was needed. In the presence of aged garlic extract the activities of hepatic efflux transporters (Pgp, MRP-2) changed, which was observed as significant permeability changes of tested human immunodeficiency virus (HIV) protease inhibitors. Darunavir efflux significantly increased, whereas that of saquinavir significantly decreased. Because of the observed in vitro interactions between aged garlic extract and HIV protease inhibitors (darunavir, saquinavir), any alterations of in vivo liver transport in the presence of garlic phytochemicals could also significantly influence darunavir/saquinavir hepatocyte intracellular concentrations and hence their bioavailabilities. Therefore this aspect needs further in vivo animal evaluation.

  12. Comparative Characterization of Shiga Toxin Type 2 and Subtilase Cytotoxin Effects on Human Renal Epithelial and Endothelial Cells Grown in Monolayer and Bilayer Conditions

    PubMed Central

    Álvarez, Romina S.; Sacerdoti, Flavia; Jancic, Carolina; Paton, Adrienne W.; Paton, James C.; Ibarra, Cristina; Amaral, María M.

    2016-01-01

    Postdiarrheal hemolytic uremic syndrome (HUS) affects children under 5 years old and is responsible for the development of acute and chronic renal failure, particularly in Argentina. This pathology is a complication of Shiga toxin (Stx)-producing Escherichia coli infection and renal damage is attributed to Stx types 1 and 2 (Stx1, Stx2) produced by Escherichia coli O157:H7 and many other STEC serotypes. It has been reported the production of Subtilase cytotoxin (SubAB) by non-O157 STEC isolated from cases of childhood diarrhea. Therefore, it is proposed that SubAB may contribute to HUS pathogenesis. The human kidney is the most affected organ because very Stx-sensitive cells express high amounts of biologically active receptor. In this study, we investigated the effects of Stx2 and SubAB on primary cultures of human glomerular endothelial cells (HGEC) and on a human tubular epithelial cell line (HK-2) in monoculture and coculture conditions. We have established the coculture as a human renal proximal tubule model to study water absorption and cytotoxicity in the presence of Stx2 and SubAB. We obtained and characterized cocultures of HGEC and HK-2. Under basal conditions, HGEC monolayers exhibited the lowest electrical resistance (TEER) and the highest water permeability, while the HGEC/HK-2 bilayers showed the highest TEER and the lowest water permeability. In addition, at times as short as 20–30 minutes, Stx2 and SubAB caused the inhibition of water absorption across HK-2 and HGEC monolayers and this effect was not related to a decrease in cell viability. However, toxins did not have inhibitory effects on water movement across HGEC/HK-2 bilayers. After 72 h, Stx2 inhibited the cell viability of HGEC and HK-2 monolayers, but these effects were attenuated in HGEC/HK-2 bilayers. On the other hand, SubAB cytotoxicity shows a tendency to be attenuated by the bilayers. Our data provide evidence about the different effects of these toxins on the bilayers respect to the

  13. Kinetics and thermodynamics of biodegradation of hydrolyzed polyacrylamide under anaerobic and aerobic conditions.

    PubMed

    Zhao, Lanmei; Bao, Mutai; Yan, Miao; Lu, Jinren

    2016-09-01

    Kinetics and thermodynamics of hydrolyzed polyacrylamide (HPAM) biodegradation in anaerobic and aerobic activated sludge biochemical treatment systems were explored to determine the maximum rate and feasibility of HPAM biodegradation. The optimal nutrient proportions for HPAM biodegradation were determined to be 0.08g·L(-1) C6H12O6, 1.00g·L(-1) NH4Cl, 0.36g·L(-1) NaH2PO4 and 3.00g·L(-1) K2HPO4 using response surface methodology (RSM). Based on the kinetics, the maximum HPAM biodegradation rates were 16.43385mg·L(-1)·d(-1) and 2.463mg·L(-1)·d(-1) in aerobic and anaerobic conditions, respectively. The activation energy (Ea) of the aerobic biodegradation was 48.9897kJ·mol(-1). Entropy changes (ΔS) of biochemical treatment system decreased from 216.21J·K(-1) to 2.39J·K(-1). Thermodynamic windows of opportunity for HPAM biodegradation were drawn. And it demonstrated HPAM was biodegraded into acetic acid and CO2 under laboratory conditions. Growth-process equations for functional bacteria anaerobically grown on polyacrylic acid were constructed and it confirmed electron equivalence between substrate and product.

  14. Ion distribution measured by electron probe X-ray microanalysis in apoplastic and symplastic pathways in root cells in sunflower plants grown in saline medium.

    PubMed

    Ebrahimi, Reza; Bhatla, S C

    2012-09-01

    Little is known about how salinity affects ions distribution in root apoplast and symplast. Using x-ray microanalysis, ions distribution and the relative contribution of apoplastic and symplastic pathways for delivery of ions to root xylem were studied in sunflower plants exposed to moderate salinity (EC=6). Cortical cells provided a considerably extended Na(+) and Cl(-) storage facility. Their contents are greater in cytoplasm (root symplast) as compared to those in intercellular spaces (root apoplast). Hence, in this level of salinity, salt damage in sunflower is not dehydration due to extracellular accumulation of sodium and chloride ions, as suggested in the Oertli hypothesis. On the other hand, reduction in calcium content due to salinity in intercellular space is less than reduction in the cytoplasm of cortical cells. It seems that sodium inhibits the radial movement of calcium in symplastic pathway more than in the apoplastic pathway. The cell wall seems to have an important role in providing calcium for the apoplastic pathway. Redistribution of calcium from the cell wall to intercellular space is because of its tendency towards xylem through the apoplastic pathway. This might be a strategy to enhance loading of calcium to xylem elements and to reduce calcium deficiency in young leaves under salinity. This phenomenon may be able to increase salt tolerance in sunflower plants. Supplemental calcium has been found to be effective in reducing radial transport of Na(+) across the root cells and their loading into the xylem, but not sodium absorption. Supplemental calcium enhanced Ca(2+) uptake and influx into roots and transport to stele.

  15. Use of a feline respiratory epithelial cell culture system grown at the air-liquid interface to characterize the innate immune response following feline herpesvirus 1 infection.

    PubMed

    Nelli, Rahul K; Maes, Roger; Kiupel, Matti; Hussey, Gisela Soboll

    2016-03-02

    Infection with feline herpesvirus-1 (FHV-1) accounts for 50% of viral upper respiratory diseases in domestic cats and is a significant cause of ocular diseases. Despite the clinical significance and high prevalence of FHV-1 infection, currently available vaccines cannot completely protect cats from infection and lifelong latency. FHV-1 infects via the mucous membranes and replicates in respiratory epithelial cells, but very little is known about the early innate immunity at this site. To address questions about immunity to FHV-1, feline respiratory epithelial cells cultured at air-liquid interface (ALI-FRECs) were established by collecting respiratory tracts from 6 healthy cats after euthanasia. Cells were isolated, cultured and characterized histologically and immunologically before infection with FHV-1. The expression of Toll-like receptors (TLRs), cytokine and chemokine responses were measured by real time PCR. ALI-FRECs morphologically resembled the natural airways of cats with multilayered columnar epithelial cells and cilia. Immunological properties of the natural airways were maintained in ALI-FRECs, as evidenced by the expression of TLRs, cytokines, chemokines, interferons, beta-defensins, and other regulatory genes. Furthermore, ALI-FRECs were able to support infection and replication of FHV-1, as well as modulate transcriptional regulation of various immune genes in response to infection. IL-1β and TNFα were increased in ALI-FRECs by 24hpi, whereas expression levels of IFN-α and TLR9 were not increased until 36hpi. In contrast, TLR3, GM-CSF and TGF-1β expression was down-regulated at 36hpi. The data presented show the development of a system ideal for investigating the molecular pathogenesis and immunity of FHV-1 or other respiratory pathogens.

  16. Biological behaviour of human umbilical artery smooth muscle cell grown on nickel-free and nickel-containing stainless steel for stent implantation

    NASA Astrophysics Data System (ADS)

    Li, Liming; An, Liwen; Zhou, Xiaohang; Pan, Shuang; Meng, Xin; Ren, Yibin; Yang, Ke; Guan, Yifu

    2016-01-01

    To evaluate the clinical potential of high nitrogen nickel-free austenitic stainless steel (HNNF SS), we have compared the cellular and molecular responses of human umbilical artery smooth muscle cells (HUASMCs) to HNNF SS and 316L SS (nickel-containing austenitic 316L stainless steel). CCK-8 analysis and flow cytometric analysis were used to assess the cellular responses (proliferation, apoptosis, and cell cycle), and quantitative real-time PCR (qRT-PCR) was used to analyze the gene expression profiles of HUASMCs exposed to HNNF SS and 316L SS, respectively. CCK-8 analysis demonstrated that HUASMCs cultured on HNNF SS proliferated more slowly than those on 316L SS. Flow cytometric analysis revealed that HNNF SS could activate more cellular apoptosis. The qRT-PCR results showed that the genes regulating cell apoptosis and autophagy were up-regulated on HNNF SS. Thus, HNNF SS could reduce the HUASMC proliferation in comparison to 316L SS. The findings furnish valuable information for developing new biomedical materials for stent implantation.

  17. Biological behaviour of human umbilical artery smooth muscle cell grown on nickel-free and nickel-containing stainless steel for stent implantation

    PubMed Central

    Li, Liming; An, Liwen; Zhou, Xiaohang; Pan, Shuang; Meng, Xin; Ren, Yibin; Yang, Ke; Guan, Yifu

    2016-01-01

    To evaluate the clinical potential of high nitrogen nickel-free austenitic stainless steel (HNNF SS), we have compared the cellular and molecular responses of human umbilical artery smooth muscle cells (HUASMCs) to HNNF SS and 316L SS (nickel-containing austenitic 316L stainless steel). CCK-8 analysis and flow cytometric analysis were used to assess the cellular responses (proliferation, apoptosis, and cell cycle), and quantitative real-time PCR (qRT-PCR) was used to analyze the gene expression profiles of HUASMCs exposed to HNNF SS and 316L SS, respectively. CCK-8 analysis demonstrated that HUASMCs cultured on HNNF SS proliferated more slowly than those on 316L SS. Flow cytometric analysis revealed that HNNF SS could activate more cellular apoptosis. The qRT-PCR results showed that the genes regulating cell apoptosis and autophagy were up-regulated on HNNF SS. Thus, HNNF SS could reduce the HUASMC proliferation in comparison to 316L SS. The findings furnish valuable information for developing new biomedical materials for stent implantation. PMID:26727026

  18. Angiogenic tube formation of bovine aortic endothelial cells grown on patterns formed by H2/He plasma treatment of the plasma polymerized hexamethyldisiloxane film.

    PubMed

    Park, Jisoo; Ha, Myunghoon; Lee, Hye-Rim; Park, Heonyong; Yu, Jung-Hoon; Boo, Jin-Hyo; Jung, Donggeun

    2015-06-27

    Angiogenesis, the process to generate new vessels, is necessary for normal development in children as well as the wound healing and the tumor growth in adults. Therefore, it is physiologically and/or pathophysiologically significant to monitor angiogenesis. However, classical in vitro methods to evaluate angiogenesis take a long time and are expensive. Here, the authors developed a novel method to analyze the angiogenesis in a simple and economical way, using patterned films. In this study, the authors fabricated a plasma polymerized hexamethyldisiloxane (PPHMDSO) thin film deposited by capacitively coupled plasma chemical vapor deposition system with various plasma powers. The patterned PPHMDSO film was plasma treated by 10:90 H2/He mixture gas through a metal shadow mask. The films were characterized by water contact angle, atomic force microscopy, x-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy analyses. Our results show that the PPHMDSO film suppresses the cell adhesion, whereas surface modified PPHMDSO film enhances the cell adhesion and proliferation. From cell culture experiments, the authors found that the patterned film with 300 μm line interval was most efficient to evaluate the tube formation, a sapient angiogenic indicator. This patterned film will provide an effective and promising method for evaluating angiogenesis.

  19. Aerobic sugar metabolism in the spoilage yeast Zygosaccharomyces bailii.

    PubMed

    Merico, Annamaria; Capitanio, Daniele; Vigentini, Ileana; Ranzi, Bianca Maria; Compagno, Concetta

    2003-12-01

    Despite the importance of some Zygosaccharomyces species as agents causing spoilage of food, the carbon and energy metabolism of most of them is yet largely unknown. This is the case with Zygosaccharomyces bailii. In this study the occurrence of the Crabtree effect in the petite-negative yeast Z. bailii ATCC 36947 was investigated. In this yeast the aerobic ethanol production is strictly dependent on the carbon source utilised. In glucose-limited continuous cultures a very low level of ethanol was produced. In fructose-limited continuous cultures ethanol was produced at a higher level and its production increased with the dilution rate. As a consequence, on fructose the onset of respiro-fermentative metabolism caused a reduction in biomass yield. An immediate aerobic alcoholic fermentation in Z. bailii was observed during the transition from sugar limitation to sugar excess, both on glucose and on fructose. The analysis of some key enzymes of the fermentative metabolism showed a high level of acetyl-CoA synthetase in Z. bailii growing on fructose. At high dilution rates, the activities of glucose- and fructose-phosphorylating enzymes, as well as of pyruvate decarboxylase and alcohol dehydrogenase, were higher in cells during growth on fructose than on glucose.

  20. Aerobic biodegradation of trichloroethylene by microorganisms that degrade aromatic compounds

    SciTech Connect

    Lu, C.J.; Chang, C.Y.; Lee, C.M.

    1995-12-31

    Aerobic biodegradation of trichloroethylene (TCE) at an initial concentration of 80 mg/L with and without the presence of an aromatic compound was conducted with a series of batch reactors. The target aromatic compounds were benzene, toluene, and catechol. The aromatics-acclimated microorganisms were used as the cell source for the batch study. The results indicated that the presence of an aromatic compound was required to initiate the aerobic biodegradation of TCE by the aromatic-utilizing microorganisms. The addition of benzene or toluene initiated the removal of TCE. However, TCE removal was not proportional to the initial concentration of the aromatic compounds. The presence of an aromatic compound at an initial concentration of 5 mg/L resulted in better TCE removal in comparison with that at 1 or 20 mg/L. TCE removal was still significant after the depletion of the aromatic compound, but at a lower rate. The presence of catechol, an intermediate of the biodegradation of an aromatic compound, did not initiate the biodegradation of TCE by the catechol-utilizing microorganisms.

  1. Fatiguing upper body aerobic exercise impairs balance.

    PubMed

    Douris, Peter C; Handrakis, John P; Gendy, Joseph; Salama, Mina; Kwon, Dae; Brooks, Richard; Salama, Nardine; Southard, Veronica

    2011-12-01

    Douris, PC, Handrakis, JP, Gendy, J, Salama, M, Kwon, D, Brooks, R, Salama, N, and Southard, V. Fatiguing upper body aerobic exercise impairs balance. J Strength Cond Res 25(12): 3299-3305, 2011-There are many studies that have examined the effects of selectively fatiguing lower extremity muscle groups with various protocols, and they have all shown to impair balance. There is limited research regarding the effect of fatiguing upper extremity exercise on balance. Muscle fiber-type recruitment patterns may be responsible for the difference between balance impairments because of fatiguing aerobic and anaerobic exercise. The purpose of our study was to investigate the effect that aerobic vs. anaerobic fatigue, upper vs. lower body fatigue will have on balance, and if so, which combination will affect balance to a greater degree. Fourteen healthy subjects, 7 men and 7 women (mean age 23.5 ± 1.7 years) took part in this study. Their mean body mass index was 23.6 ± 3.2. The study used a repeated-measures design. The effect on balance was documented after the 4 fatiguing conditions: aerobic lower body (ALB), aerobic upper body (AUB), anaerobic lower body, anaerobic upper body (WUB). The aerobic conditions used an incremental protocol performed to fatigue, and the anaerobic used the Wingate protocol. Balance was measured as a single-leg stance stability score using the Biodex Balance System. A stability score for each subject was recorded immediately after each of the 4 conditions. A repeated-measures analysis of variance with the pretest score as a covariate was used to analyze the effects of the 4 fatiguing conditions on balance. There were significant differences between the 4 conditions (p = 0.001). Post hoc analysis revealed that there were significant differences between the AUB, mean score 4.98 ± 1.83, and the WUB, mean score 4.09 ± 1.42 (p = 0.014) and between AUB and ALB mean scores 4.33 ± 1.40 (p = 0.029). Normative data for single-leg stability testing for

  2. Quantification of confocal images of biofilms grown on irregular surfaces

    PubMed Central

    Ross, Stacy Sommerfeld; Tu, Mai Han; Falsetta, Megan L.; Ketterer, Margaret R.; Kiedrowski, Megan R.; Horswill, Alexander R.; Apicella, Michael A.; Reinhardt, Joseph M.; Fiegel, Jennifer

    2014-01-01

    Bacterial biofilms grow on many types of surfaces, including flat surfaces such as glass and metal and irregular surfaces such as rocks, biological tissues and polymers. While laser scanning confocal microscopy can provide high-resolution images of biofilms grown on any surface, quantification of biofilm-associated bacteria is currently limited to bacteria grown on flat surfaces. This can limit researchers studying irregular surfaces to qualitative analysis or quantification of only the total bacteria in an image. In this work, we introduce a new algorithm called modified connected volume filtration (MCVF) to quantify bacteria grown on top of an irregular surface that is fluorescently labeled or reflective. Using the MCVF algorithm, two new quantification parameters are introduced. The modified substratum coverage parameter enables quantification of the connected-biofilm bacteria on top of the surface and on the imaging substratum. The utility of MCVF and the modified substratum coverage parameter were shown with Pseudomonas aeruginosa and Staphylococcus aureus biofilms grown on human airway epithelial cells. A second parameter, the percent association, provides quantified data on the colocalization of the bacteria with a labeled component, including bacteria within a labeled tissue. The utility of quantifying the bacteria associated with the cell cytoplasm was demonstrated with Neisseria gonorrhoeae biofilms grown on cervical epithelial cells. This algorithm provides more flexibility and quantitative ability to researchers studying biofilms grown on a variety of irregular substrata. PMID:24632515

  3. Alterations of leaf cell ultrastructures and AFLP DNA profiles in Earth-grown tomato plants propagated from long-term six years Mir-flown seeds

    NASA Astrophysics Data System (ADS)

    Liu, Min; Xue, Huai; Pan, Yi; Zhang, Chunhua; Lu, Jinying

    Leaf cell ultrastructures and DNA variations in the firstand the second-generation of Earthgrown tomato (Lycopersicon esculentun Mill) plants that had been endured a long-term six years spaceflight in the Mir were compared to their ground-based control plants, under observations with a Transmission Electron Microscope and the Amplification Fragment Length Polymorphism (AFLP) analysis. For alterations in the morphological ultrastructures, one plant among the 11 first-generation plants generated from 30 Mir-flown seeds had a three-layered palisade cell structure, while other 10 first-generation plants and all ground-based controls had one-layered palisade cell structure in leaves. Starch grains were larger and in clusters, numbers of starch grains increased in the chloroplasts in the Mir-flown plants. Leaf cells became contracted and deformed, and cell shape patterns were different in the Mir-flown plants. For the leaf genomic DNA alterations, 34 DNA bands were polymorphic with a 1.32% polymorphism among 2582 DNA bands in the first-generation Mir-flown plants. Band types in the spaceflight treated plants were also different from those in the ground-based control. Of 11 survived first-generation plants, 7 spaceflight treated plants (Plant Nos. 1-6 and No. 9) had a same 7 polymorphic bands and a same 0.27%DNA mutation. The DNA mutation rate was greatest in Plants No.10 and No.7 (0.90% and 0.94%), less in Plant No.11 (0.31%) and least in Plant No.8 (0.20%). For the 38 send-generation plants propagated from the No. 5 Mir-flown seed, 6 DNA bands were polymorphic with a 0.23% polymorphism among 2564 amplified DNA bands. Among those 38 second-generation plants amplified by primer pair (E4: ACC, M8: CTT), one DNA band disappeared in 29 second-generation plants and in the original Mir-flown No. 5 plant, compared to the ground-base controls. Among the 38 second-generation plants generated from the Mir-flown No. 5 seed, the DNA band types of 29 second-generation plants were

  4. High quality boron-doped epitaxial layers grown at 200°C from SiF4/H2/Ar gas mixtures for emitter formation in crystalline silicon solar cells

    NASA Astrophysics Data System (ADS)

    Léal, Ronan; Haddad, Farah; Poulain, Gilles; Maurice, Jean-Luc; Roca i Cabarrocas, Pere

    2017-02-01

    Controlling the doping profile in solar cells emitter and front/back surface field is mandatory to reach high efficiencies. In the current state of the art, these doped layers are made by dopant diffusion at around 900°C, which implies potential temperature induced damages in the c-Si absorber and for which a precise control of doping is difficult. An alternative solution based on boron-doped epitaxial silicon layers grown by plasma-enhanced chemical vapor deposition (PECVD) from 200°C using SiF4/H2/Ar/B2H6 chemistry is reported. The structural properties of the doped and undoped epitaxial layers were assessed by spectroscopic ellipsometry (SE), high resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD). The incorporation of boron has been studied via plasma profiling time of flight mass spectrometry (PP-TOFMS) and secondary ion mass spectrometry (SIMS) measurements. The boron-doped epitaxial layers revealed excellent structural and electrical properties even for high carrier concentrations (>1019cm-3). Sheet resistances between 100 and 130 Ω/sq can been obtained depending on the thickness and the doping concentration, which is within the range of targeted values for emitters in c-Si solar cells. Electrochemical capacitance voltage (ECV) revealed a uniform doping profile around 3.1019 cm-3 and by comparing with SIMS measurement a doping efficiency around 50% has been found.

  5. Transparent Conducting ZnO:B Thin Films Grown by Ultraviolet Light Assisted Metal Organic Chemical Vapor Deposition Using Triethylboron for Cu(In,Ga)Se2 Solar Cells

    NASA Astrophysics Data System (ADS)

    Kobayashi, Taizo; Yamauchi, Kotaro; Mise, Takahiro; Nakada, Tokio

    2012-10-01

    High-efficiency cadmium-free Cu(In,Ga)Se2 (CIGS) thin-film solar cells have been fabricated using a zinc compound buffer layer deposited by the chemical bath deposition (CBD) process. However, the zinc compound buffer layers such as ZnS(O,OH) are prone to plasma-induced damage during the subsequent ZnO sputtering process. A process causing less damage such as metal-organic chemical vapor deposition (MOCVD) is thus required for ZnO-based transparent conducting oxide (TCO) layers. In the present work, the boron-doped zinc oxide (ZnO:B) films were grown by MOCVD using diethyl zinc (DEZ), H2O, and low-toxicity triethylboron (TEB). An UV-assisted MOCVD process was developed in order to reduce the resistivity of ZnO:B films. As a result, the resisitivity significantly decreased together with the increased electron mobility and carrier concentration. The comparison of performance was also carried out for the ZnS(O,OH)/CIGS solar cells with MOCVD-deposited ZnO:B and sputter-deposited ZnO:Al window layers.

  6. Detection of the quantity of kinesin and microgravity-sensitive kinesin genes in rat bone marrow stromal cells grown in a simulated microgravity environment

    NASA Astrophysics Data System (ADS)

    Ni, Chengzhi; Wang, Chunyan; Li, Yuan; Li, Yinghui; Dai, Zhongquan; Zhao, Dongming; Sun, Hongyi; Wu, Bin

    2011-06-01

    Kinesin and kinesin-like proteins (KLPs) constitute a superfamily of microtubule motor proteins found in all eukaryotic organisms. Members of the kinesin superfamily are known to play important roles in many fundamental cellular and developmental processes. To date, few published studies have reported on the effects of microgravity on kinesin expression. In this paper, we describe the expression pattern and microgravity-sensitive genes of kinesin in rat bone marrow stromal cells cultured in a ground-based rotating bioreactor. The quantity of kinesin under the clinorotation condition was examined by immunoblot analysis with anti-kinesin. Furthermore, the distribution of kinesin at various times during clinorotation was determined by dual immunostaining, using anti-kinesin monoclonal antibody or anti-β-tubulin monoclonal antibody. In terms of kinesin quantity, we found that the ratios of the amounts of clinorotated/stationary KLPs decreased from clinorotation day 5 to day 10, although it increased on days 2 and 3. Immunofluorescence analysis revealed that kinesin in the nucleus was the first to be affected by simulated microgravity, following the kinesin at the periphery that was affected at various times during clinorotation. Real-time RT-PCR analysis of kinesin mRNA expression was performed and led to the identification of 3 microgravity-sensitive kinesin genes: KIF9, KIFC1, and KIF21A. Our results suggest that kinesin has a distinct expression pattern, and the identification of microgravity-sensitive kinesin genes offers insight into fundamental cell biology.

  7. CFD Study of Full-Scale Aerobic Bioreactors: Evaluation of Dynamic O2 Distribution, Gas-Liquid Mass Transfer and Reaction

    SciTech Connect

    Humbird, David; Sitaraman, Hariswaran; Stickel, Jonathan; Sprague, Michael A.; McMillan, Jim

    2016-11-18

    If advanced biofuels are to measurably displace fossil fuels in the near term, they will have to operate at levels of scale, efficiency, and margin unprecedented in the current biotech industry. For aerobically-grown products in particular, scale-up is complex and the practical size, cost, and operability of extremely large reactors is not well understood. Put simply, the problem of how to attain fuel-class production scales comes down to cost-effective delivery of oxygen at high mass transfer rates and low capital and operating costs. To that end, very large reactor vessels (>500 m3) are proposed in order to achieve favorable economies of scale. Additionally, techno-economic evaluation indicates that bubble-column reactors are more cost-effective than stirred-tank reactors in many low-viscosity cultures. In order to advance the design of extremely large aerobic bioreactors, we have performed computational fluid dynamics (CFD) simulations of bubble-column reactors. A multiphase Euler-Euler model is used to explicitly account for the spatial distribution of air (i.e., gas bubbles) in the reactor. Expanding on the existing bioreactor CFD literature (typically focused on the hydrodynamics of bubbly flows), our simulations include interphase mass transfer of oxygen and a simple phenomenological reaction representing the uptake and consumption of dissolved oxygen by submerged cells. The simulations reproduce the expected flow profiles, with net upward flow in the center of column and downward flow near the wall. At high simulated oxygen uptake rates (OUR), oxygen-depleted regions can be observed in the reactor. By increasing the gas flow to enhance mixing and eliminate depleted areas, a maximum oxygen transfer (OTR) rate is obtained as a function of superficial velocity. These insights regarding minimum superficial velocity and maximum reactor size are incorporated into NREL's larger techno-economic models to supplement standard reactor design equations.

  8. Nucleolus in clinostat-grown plants

    SciTech Connect

    Shen-Miller, J.; Dannenhoffer, J. ); Hinchman, R. )

    1991-05-01

    The clinostat is an apparatus that is used to mimic zero gravity in studies of plant growth in the absence of gravitropic response. Clinostat-grown tissue cultures of carrot exhibit significant increases both in the number of nuclei containing more than one nucleolus and in nucleolar volume. Oat seedlings germinated and grown on clinostats exhibit a decreased rate of shoot elongation, increased tissue sensitivity to applied auxin, and an increased response to gravitropic stimulation. Clinostat treatment clearly affects plant metabolism. The nucleolus is the region in the nucleus where ribosome synthesis and assembly take place. The 18S, 5.8S, and 25S ribosomal genes, in tandem units, are located in the nucleolus. Ribosomes orchestrate the production of all proteins that are necessary for the maintenance of cell growth, development, and survival. A full study of the effects of nullification of gravitropism, by clinostat rotation, on nucleolar development in barley has been initiated. The authors study developmental changes of nucleolar number and diameter in clinostat-grown root tissues. Preliminary results show that barley roots exhibit changes in nucleolar number and diameter. Growth rates of barley root and shoot also appear to be reduced, in measurements of both length and weight.

  9. Growing rice aerobically markedly decreases mercury accumulation by reducing both Hg bioavailability and the production of MeHg.

    PubMed

    Wang, Xun; Ye, Zhihong; Li, Bing; Huang, Linan; Meng, Mei; Shi, Jianbo; Jiang, Guibin

    2014-01-01

    Rice consumption represents a major route of mercury (Hg) and methylmercury (MeHg) exposure for those living in certain areas of inland China. In this study we investigated the effects of water management on bioavailable Hg, MeHg, and sulfate-reducing bacteria (SRB, abundance and community composition) in rhizosphere soil, and total Hg (THg) and MeHg in rice plants grown under glasshouse and paddy field conditions. Aerobic conditions greatly decreased the amount of THg and MeHg taken up by rice plants and affected their distribution in different plant tissues. There were positive correlations between bioavailable Hg and THg in brown rice and roots and between numbers of SRB and MeHg in brown rice, roots, and rhizosphere soil. Furthermore, the community composition of SRB was dramatically influenced by the water management regimes. Our results demonstrate that the greatly reduced bioavailability of Hg and production of MeHg are due to decreased SRB numbers and proportion of Hg methylators in the rhizosphere under aerobic conditions. These are the main reasons for the reduced Hg and MeHg accumulation in aerobically grown rice. Water management is indicated as an effective measure that can be used to reduce Hg and MeHg uptake by rice plants from Hg-contaminated paddy fields.

  10. Effect of habitual aerobic exercise on body weight and arterial function in overweight and obese men.

    PubMed

    Miyaki, Asako; Maeda, Seiji; Yoshizawa, Mutsuko; Misono, Maiko; Saito, Yoko; Sasai, Hiroyuki; Kim, Maeng-Kyu; Nakata, Yoshio; Tanaka, Kiyoji; Ajisaka, Ryuichi

    2009-09-15

    The effect of habitual exercise on vascular function, including central arterial distensibility and endothelial function, in obese subjects has not yet been clarified. We investigated whether aerobic exercise training affects central arterial distensibility and endothelial function in middle-age overweight and obese men. A total of 21 overweight and obese men (age 50 +/- 2 years, body mass index 30 +/- 1 kg/m(2)) completed a 12-week aerobic exercise intervention. Aerobic exercise training significantly reduced their body weight and resulted in a significant decrease in body mass index. After the weight-reduction exercise program, carotid arterial compliance (determined by simultaneous B-mode ultrasonography and arterial applanation tonometry on the common carotid artery) significantly increased; and the beta-stiffness index, an index of arterial compliance adjusted for distending pressure, significantly decreased. The concentrations of plasma endothelin-1, a potent vasoconstrictor peptide produced by vascular endothelial cells, significantly decreased and plasma nitric oxide (measured as the stable end product [nitrite/nitrate]), a potent vasodilator produced by vascular endothelial cells, significantly increased after the weight-reduction exercise program. In conclusion, weight reduction by aerobic exercise training in overweight and obese men increased the central arterial distensibility. This increase might contribute to the improvement in endothelial function, as assessed by a decrease in endothelin-1 and an increase in nitric oxide, after exercise training-induced weight loss.

  11. Characteristics of Ga-Rich Cu(In, Ga)Se2 Solar Cells Grown on Ga-Doped ZnO Back Contact.

    PubMed

    Sun, Qian; Kim, Kyoung-Bo; Jeon, Chan-Wook

    2016-05-01

    Wide bandgap Cu(In,Ga)Se2 (CIGS) thin films were deposited on Ga-rich Ga:ZnO (GZO) or MoN/GZO by single-stage co-evaporation. CIGS/TCO interface phases, such as resistive n-type Ga2O3, which are likely to have formed during the high temperature growth of Ga-rich CIGS, can deteriorate the solar cell performance. Although some Ga accumulation was observed in both of the CIGS/GZO and CIGS/MoN/GZO interfaces formed at 520 degrees C, the Ga oxide layer was absent. On the other hand, their current-voltage characteristics showed strong roll-over behavior regardless of the MoN diffusion barrier. The strong Schottky barrier formation at the CLGS/GZO junction due to the low work function of GZO, was attributed to current blocking at a high forward bias.

  12. The structure of the glucuronoxylomannan produced by culinary-medicinal yellow brain mushroom (Tremella mesenterica Ritz.:Fr., Heterobasidiomycetes) grown as one cell biomass in submerged culture.

    PubMed

    Vinogradov, Evgeny; Petersen, Bent O; Duus, Jens Ø; Wasser, Solomon

    2004-06-01

    The yellow brain mushroom Tremella mesenterica possesses a wide spectrum of medicinal properties, including immunostimulating, protecting against radiation, antidiabetic, anti-inflammatory, hypocholesterolemic, hepatoprotective, and antiallergic effects. A unique feature of T. mesenterica is that most of the above mentioned medicinal properties depend on glucuronoxylomannan (GXM) contained in fruiting bodies or produced in pure culture conditions. We developed a new strain of T. mesenterica CBS 101939, which grows in submerged culture and offers superior yields of one-cell biomass rich in exocellular heteropolysaccharide GXM. The structure of the GXM was analyzed by NMR spectroscopy and chemical methods. The polysaccharide has a defined repeating unit structure, which is O-acetylated at several points: [structure: see text]. These results differ from previously published structure of Tremella extracellular polysaccharides, where mannan backbone was believed to be randomly glycosylated with xylan chains of different length.

  13. Aerobic and two-stage anaerobic-aerobic sludge digestion with pure oxygen and air aeration.

    PubMed

    Zupancic, Gregor D; Ros, Milenko

    2008-01-01

    The degradability of excess activated sludge from a wastewater treatment plant was studied. The objective was establishing the degree of degradation using either air or pure oxygen at different temperatures. Sludge treated with pure oxygen was degraded at temperatures from 22 degrees C to 50 degrees C while samples treated with air were degraded between 32 degrees C and 65 degrees C. Using air, sludge is efficiently degraded at 37 degrees C and at 50-55 degrees C. With oxygen, sludge was most effectively degraded at 38 degrees C or at 25-30 degrees C. Two-stage anaerobic-aerobic processes were studied. The first anaerobic stage was always operated for 5 days HRT, and the second stage involved aeration with pure oxygen and an HRT between 5 and 10 days. Under these conditions, there is 53.5% VSS removal and 55.4% COD degradation at 15 days HRT - 5 days anaerobic, 10 days aerobic. Sludge digested with pure oxygen at 25 degrees C in a batch reactor converted 48% of sludge total Kjeldahl nitrogen to nitrate. Addition of an aerobic stage with pure oxygen aeration to the anaerobic digestion enhances ammonium nitrogen removal. In a two-stage anaerobic-aerobic sludge digestion process within 8 days HRT of the aerobic stage, the removal of ammonium nitrogen was 85%.

  14. Nitrification and aerobic denitrification in anoxic-aerobic sequencing batch reactor.

    PubMed

    Alzate Marin, Juan C; Caravelli, Alejandro H; Zaritzky, Noemí E

    2016-01-01

    The aim of this study was to evaluate the feasibility of achieving nitrogen (N) removal using a lab-scale sequencing batch reactor (SBR) exposed to anoxic/aerobic (AN/OX) phases, focusing to achieve aerobic denitrification. This process will minimize emissions of N2O greenhouse gas. The effects of different operating parameters on the reactor performance were studied: cycle duration, AN/OX ratio, pH, dissolved oxygen concentration (DOC), and organic load. The highest inorganic N removal (NiR), close to 70%, was obtained at pH=7.5, low organic load (440mgCOD/(Lday)) and high aeration given by 12h cycle, AN/OX ratio=0.5:1.0 and DOC higher than 4.0mgO2/L. Nitrification followed by high-rate aerobic denitrification took place during the aerobic phase. Aerobic denitrification could be attributed to Tetrad-forming organisms (TFOs) with phenotype of glycogen accumulating organisms using polyhydroxyalkanoate and/or glycogen storage. The proposed AN/OX system constitutes an eco-friendly N removal process providing N2 as the end product.

  15. Alcohol and single-cell protein production by Kluyveromyces in concentrated whey permeates with reduced ash

    SciTech Connect

    Mahmoud, M.M.; Kosikowski, F.V.

    1982-01-01

    Five Kluyveromyces yeasts were grown in concentrated whey permeates under aerobic and anaerobic conditions to produce single-cell protein and ethanol. K. fragilis NRRL Y2415 produced the highest yield of alcohol, 9.1%, and K. bulgaricus ATCC 1605 gave the highest yield of biomass, 13.5 mg/mL. High ash, apparently through Na and K effects, inhibited production of biomass and alcohol. A 0.77% ash was optimum. Lactose utilization was more rapid under aerobic than anaerobic conditions. (NH/sub 4/)/sub 2/SO/sub 4/ and urea supplementation were without effect on yeast growth or were slightly inhibitory. A 1% peptone inclusion gave the highest biomass yield with minimum alcohol production.

  16. Laboratory Study of Chemical Speciation of Mercury in Lake Sediment and Water under Aerobic and Anaerobic Conditions

    PubMed Central

    Regnell, Olof; Tunlid, Anders

    1991-01-01

    Chemical speciation and partitioning of radiolabeled HgCl2 were studied in model aquatic systems consisting of undisturbed eutrophic lake sediment and water in plastic cylinders. The cylinders were either gradually made anaerobic by a gentle flow of N2-CO2 or kept aerobic by air flow. The proportion of methylated 203Hg was significantly higher, in both water and sediment, in the anaerobic systems than in the aerobic systems. The composition and total concentration of fatty acids originating from bacterial phospholipids, as well as the concentration of vitamin B12, including related cobalamins, were similar in sediments from the anaerobic and aerobic systems. Bacterial cell numbers were, on average, 3.6 times higher in the anaerobic water columns than in the aerobic ones. Volatilization of 203Hg occurred in all systems except in an autoclaved control and was of similar magnitudes in the anaerobic and aerobic systems. Incorporation of 203Hg into the sediment was significantly faster in the aerobic systems than in the anaerobic systems. These results suggest that episodes of anoxia in bottom waters and sediment cause an increase in net mercury methylation and, hence, an increase in bioavailable mercury. PMID:16348444

  17. Embryonic Stem Cell-Derived Neurons Grown on Multi-Electrode Arrays as a Novel In vitro Bioassay for the Detection of Clostridium botulinum Neurotoxins

    PubMed Central

    Jenkinson, Stephen P.; Grandgirard, Denis; Heidemann, Martina; Tscherter, Anne; Avondet, Marc-André; Leib, Stephen L.

    2017-01-01

    Clostridium botulinum neurotoxins (BoNTs) are the most poisonous naturally occurring protein toxins known to mankind and are the causative agents of the severe and potentially life-threatening disease botulism. They are also known for their application as cosmetics and as unique bio-pharmaceuticals to treat an increasing number of neurological and non-neurological disorders. Currently, the potency of biologically active BoNT for therapeutic use is mainly monitored by the murine LD50-assay, an ethically disputable test causing suffering and death of a considerable number of mice. The aim of this study was to establish an in vitro assay as an alternative to the widely used in vivo mouse bioassay. We report a novel BoNT detection assay using mouse embryonic stem cell-derived neurons (mESN) cultured on multi-electrode arrays (MEAs). After 21 days in culture, the mESN formed a neuronal network showing spontaneous bursting activity based on functional synapses and express the necessary target proteins for BoNTs. Treating cultures for 6 h with 16.6 pM of BoNT serotype A and incubation with 1.66 pM BoNT/A or 33 Units/ml of Botox® for 24 h lead to a significant reduction of both spontaneous network bursts and average spike rate. This data suggests that mESN cultured on MEAs pose a novel, biologically relevant model that can be used to detect and quantify functional BoNT effects, thus accelerating BoNT research while decreasing animal use. PMID:28280466

  18. Growth of nitrite-oxidizing bacteria by aerobic hydrogen oxidation.

    PubMed

    Koch, Hanna; Galushko, Alexander; Albertsen, Mads; Schintlmeister, Arno; Gruber-Dorninger, Christiane; Lücker, Sebastian; Pelletier, Eric; Le Paslier, Denis; Spieck, Eva; Richter, Andreas; Nielsen, Per H; Wagner, Michael; Daims, Holger

    2014-08-29

    The bacterial oxidation of nitrite to nitrate is a key process of the biogeochemical nitrogen cycle. Nitrite-oxidizing bacteria are considered a highly specialized functional group, which depends on the supply of nitrite from other microorganisms and whose distribution strictly correlates with nitrification in the environment and in wastewater treatment plants. On the basis of genomics, physiological experiments, and single-cell analyses, we show that Nitrospira moscoviensis, which represents a widely distributed lineage of nitrite-oxidizing bacteria, has the genetic inventory to utilize hydrogen (H2) as an alternative energy source for aerobic respiration and grows on H2 without nitrite. CO2 fixation occurred with H2 as the sole electron donor. Our results demonstrate a chemolithoautotrophic lifestyle of nitrite-oxidizing bacteria outside the nitrogen cycle, suggesting greater ecological flexibility than previously assumed.

  19. Targeting aerobic glycolysis: 3-bromopyruvate as a promising anticancer drug.

    PubMed

    Cardaci, Simone; Desideri, Enrico; Ciriolo, Maria Rosa

    2012-02-01

    The Warburg effect refers to the phenomenon whereby cancer cells avidly take up glucose and produce lactic acid under aerobic conditions. Although the molecular mechanisms underlying tumor reliance on glycolysis remains not completely clear, its inhibition opens feasible therapeutic windows for cancer treatment. Indeed, several small molecules have emerged by combinatorial studies exhibiting promising anticancer activity both in vitro and in vivo, as a single agent or in combination with other therapeutic modalities. Therefore, besides reviewing the alterations of glycolysis that occur with malignant transformation, this manuscript aims at recapitulating the most effective pharmacological therapeutics of its targeting. In particular, we describe the principal mechanisms of action and the main targets of 3-bromopyruvate, an alkylating agent with impressive antitumor effects in several models of animal tumors. Moreover, we discuss the chemo-potentiating strategies that would make unparalleled the putative therapeutic efficacy of its use in clinical settings.

  20. Protein Crystals Grown in Space

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A collage of protein and virus crystals, many of which were grown on the U.S. Space Shuttle or Russian Space Station, Mir. The crystals include the proteins canavalin; mouse monoclonal antibody; a sweet protein, thaumatin; and a fungal protease. Viruses are represented here by crystals of turnip yellow mosaic virus and satellite tobacco mosaic virus. The crystals are photographed under polarized light (thus causing the colors) and range in size from a few hundred microns in edge length up to more than a millimeter. All the crystals are grown from aqueous solutions and are useful for X-ray diffraction analysis. Credit: Dr. Alex McPherson, University of California, Irvine.

  1. High transmittance cadmium oxysulfide Cd(S,O) buffer layer grown by triton X-100 mediated chemical bath deposition for thin-film heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Ballipinar, Faruk; Rastogi, A. C.

    2017-01-01

    Polycrystalline 100-190 nm Cd(S,O) n-type semiconductor thin films of high transparency in the visible range are deposited by a surfactant Triton X-100 mediated chemical bath deposition process. The crystalline structure of the films revealed by X-ray diffraction data shows a cubic-CdO phase signified by (111) and (200) planes alongside the (002), (220), and (110) planes from hexagonal-CdS. The invariance of the 2θ position of the (002) CdS diffraction is interpreted in terms of the growth of the composite film essentially by the formation of a dilute interstitial alloy of CdO and CdS. This is confirmed by Raman spectra which, besides the CdS 1LO and 2LO modes at 300 and 600 cm-1, also show Raman lines from CdO at 1098 cm-1 and 952 cm-1 assigned as overtone of 2LO phonon modes and 556 cm-1 due to band crossing between LO and TO modes of CdO. Optical spectra of Cd(S,O) films show a median transmittance of >85% compared to ˜70% for CdS films in the 550-1000 nm wavelength range. The Cd(S,O) films show optical bandgap varying from 2.34 to 2.26 eV with increasing CdO fraction but retain high sub-bandgap transmission and sharp band edge threshold. The Cd(S,O) films thus offer an alternative to the CdS buffer layer in the heterojunction solar cells, which has major shortcoming of poor stability and high sub-bandgap absorption. The photoluminescence spectra of Cd(S,O) films show three green bands, of which one is the near band edge transition at 511.5 nm, the same as in CdS, the second band at 526.0 nm that red shifted from the CdS position is due to shallow donor-acceptor defects arising from structural change due to CdO, and the third band at 543.6 nm (2.28 eV) originates from direct band transition in CdO. The growth mechanism of Cd(S,O) films is described, which invokes that the Triton X-100 molecule modifies the microenvironment around adsorbed [Cd(NH3)4]2+ species, thereby inducing two concurrent reactions, one with SH- species that cause CdS formation and the

  2. Effect of spacer layer thickness on multi-stacked InGaAs quantum dots grown on GaAs (311)B substrate for application to intermediate band solar cells

    NASA Astrophysics Data System (ADS)

    Shoji, Yasushi; Narahara, Kohei; Tanaka, Hideharu; Kita, Takashi; Akimoto, Katsuhiro; Okada, Yoshitaka

    2012-04-01

    We have investigated the properties of multi-stacked layers of self-organized In0.4Ga0.6As quantum dots (QDs) on GaAs (311)B grown by molecular beam epitaxy. We found that a high degree of in-plane ordering of QDs structure with a six-fold symmetry was maintained though the growth has been performed at a higher growth rate than the conventional conditions. The dependence of photoluminescence characteristics on spacer layer thickness showed an increasing degree of electronic coupling between the stacked QDs for thinner spacer layers. The external quantum efficiency for an InGaAs/GaAs quantum dot solar cell (QDSC) with a thin spacer layer thickness increased in the longer wavelength range due to additive contribution from QD layers inserted in the intrinsic region. Furthermore, a photocurrent production by 2-step photon absorption has been observed at room temperature for the InGaAs/GaAs QDSC with a spacer layer thickness of 15 nm.

  3. Nitrogen use efficiency evaluation of aerobic rice under field capacity water potential using {sup 15}N isotopic tracer technique

    SciTech Connect

    Wahid, Ahmad Nazrul Abd; Rahim, Sahibin Abd; Rahim, Khairuddin Abdul; Harun, Abdul Rahim

    2015-09-25

    This study was carried out to evaluate the efficiency use of the nitrogen fertilizer on aerobic rice varieties MR219-4 and MR219-9 which were grown aerobically under field capacity water potential at the controlled environment area or shield house. Direct {sup 15}N isotope tracer method was used in this study, whereby the {sup 15}N isotope was utilized as a tracer for nitrogen nutrient uptake. {sup 15}N isotope presence in the samples is determined by using emission spectrometer analysis and percentage of total nitrogen is determined by using Kjeldahl method. {sup 15}N atom access value contained in the sample will be used in determining the effectiveness of the use of nitrogen in fertilizers through the specific calculation formulas. In this work, the data several data of nitrogen derived from fertilizer (Ndff), total nitrogen, nitrogen uptake and nitrogen use efficiency was obtained.

  4. Anaerobically Grown Escherichia coli Has an Enhanced Mutation Rate and Distinct Mutational Spectra

    PubMed Central

    Shewaramani, Sonal; Finn, Thomas J.; Kassen, Rees; Rainey, Paul B.

    2017-01-01

    Oxidative stress is a major cause of mutation but little is known about how growth in the absence of oxygen impacts the rate and spectrum of mutations. We employed long-term mutation accumulation experiments to directly measure the rates and spectra of spontaneous mutation events in Escherichia coli populations propagated under aerobic and anaerobic conditions. To detect mutations, whole genome sequencing was coupled with methods of analysis sufficient to identify a broad range of mutational classes, including structural variants (SVs) generated by movement of repetitive elements. The anaerobically grown populations displayed a mutation rate nearly twice that of the aerobic populations, showed distinct asymmetric mutational strand biases, and greater insertion element activity. Consistent with mutation rate and spectra observations, genes for transposition and recombination repair associated with SVs were up-regulated during anaerobic growth. Together, these results define differences in mutational spectra affecting the evolution of facultative anaerobes. PMID:28103245

  5. Intracellular azo decolorization is coupled with aerobic respiration by a Klebsiella oxytoca strain.

    PubMed

    Yu, Lei; Zhang, Xiao-Yu; Xie, Tian; Hu, Jin-Mei; Wang, Shi; Li, Wen-Wei

    2015-03-01

    Reduction of azo dye methyl red coupled with aerobic respiration by growing cultures of Klebsiella oxytoca GS-4-08 was investigated. In liquid media containing dye and 0.6 % glucose in a mineral salts base, 100 mg l(-1) of the dye are completely removed in 3 h under shaking conditions. The dye cannot be aerobically decolorized by strain GS-4-08 without extra carbon sources, indicating a co-metabolism process. Higher initial dye concentration prolonged the lag phase of the cell growth, but final cell concentrations of each batches reached a same level with range from 6.3 to 7.6 mg l(-1) after the dye adaption period. This strain showed stronger dye tolerance and decolorization ability than many reported strains. Furthermore, a new intracellular oxygen-insensitive azoreductase was isolated from this strain, and the specific activity of enzyme was 0.846 and 0.633 U mg(-1) protein in the presence of NADH and NADPH, respectively. N,N dimethyl-p-phenylenediamine and anthranilic acid were stoichiometrically released from MR dye, indicating the breakage of azo bonds accounts for the intracellular decolorization. Combining the characteristics of azoreductase, the stoichiometry of EMP, and TCA cycle, the electron transfer chain theory of aerobic respiration, and the possible mechanism of aerobic respiration coupled with azo reduction by K. oxytoca GS-4-08 are proposed. This study is expected to provide a sound theoretical basis for the development of the K. oxytoca strain in aerobic process for azo dye containing wastewaters.

  6. [Sulfa-drug wastewater treatment with anaerobic/aerobic process].

    PubMed

    Wu, L; Zhang, H; Zhu, H; Zhang, Z; Zhuang, Y; Dai, S

    2001-09-01

    Sulfa drug wastewater was treated with anaerobic/aerobic process. The removal ratios of TOC reached about 50% in anaerobic phase and about 70% in aerobic phase respectively, while volume loading rate of TOC was about 1.2 kg/(m3.d) in anaerobic phase and about 0.6 kg/(m3.d) in aerobic phase. Removal of TOC in anaerobic phase was attributed to the reduction of sulfate.

  7. [Cardiovascular protection and mechanisms of actions of aerobic exercise].

    PubMed

    Hou, Zuo-Xu; Zhang, Yuan; Gao, Feng

    2014-08-01

    It is well established that aerobic exercise exerts beneficial effect on cardiovascular system, but the underlying mechanisms are yet to be elucidated. Recent studies have shown that aerobic exercise ameliorates insulin resistance, inflammation and mitochondrial dysfunction which play important roles in the development of cardiovascular disease. In this review, we discussed the underlying mechanisms of the cardioprotective role of aerobic exercise, especially the latest progress in this field.

  8. Lipid Accumulation in Hypoxic Tissue Culture Cells

    PubMed Central

    Gordon, Gerald B.; Barcza, Maureen A.; Bush, Marilyn E.

    1977-01-01

    Lipid droplets have long been recognized by light microscopy to accumulate in hypoxic cells both in vivo and in vitro. In the present tissue culture experiments, correlative electron microscopic observations and lipid analyses were performed to determine the nature and significance of lipid accumulation in hypoxia. Strain L mouse fibroblasts were grown in suspension culture, both aerobically and under severe oxygen restriction obtained by gassing cultures daily with an 8% CO2-92% nitrogen mixture. After 48 hours, hypoxic cells showed an increase in total lipid/protein ratio of 42% over control cells. Most of this increase was accounted for by an elevation in the level of cellular triglyceride from 12.3 ± 0.9 μg/mg cell protein in aerobic cultures to 41.9 ± 0.7 in the hypoxic cultures, an increase of 240%. Levels of cellular free fatty acids (FFA) were 96% higher in the hypoxic cultures. No significant changes in the levels of cellular phospholipid or cholesterol were noted. Electron microscopic examination revealed the accumulation of homogeneous cytoplasmic droplets. The hypoxic changes were reversible upon transferring the cultures to aerobic atmospheres with disappearance of the lipid. These experiments indicate that hypoxic injury initially results in triglyceride and FFA accumulation from an inability to oxidize fatty acids taken up from the media and not from autophagic processes, as described in other types of cell injury associated with the sequestration of membranous residues and intracellular cholesterol and phospholipid accumulation. ImagesFigure 3Figure 4Figure 5Figure 6Figure 7Figure 1Figure 2 PMID:196505

  9. Characterization of the Aerobic Oxidation of cis-Dichloroethene and Vinyl Chloride in Support of Bioremediation of Chloroethene-Contaminated Sites

    DTIC Science & Technology

    2004-11-05

    medium (LB) at 37°C. All cultures were incubated aerobically with shaking at 165-250 rpm. E . coli transformants were plated on LB agar containing either...J. E . T., W. de Koning, and D. B. Janssen. 1996. Transformation kinetics of chlorinated ethenes by Methylosinus trichospo- rium OB3b and detection...acetate was added at 20 mM. Mycobacte- rium strains JS60 and mc2155 were grown at 30°C; E . coli strain JM109 was grown at 37°C. All cultures were

  10. Ammonium assimilation: An important accessory during aerobic denitrification of Pseudomonas stutzeri T13.

    PubMed

    Sun, Yilu; Feng, Liang; Li, Ang; Zhang, Xuening; Yang, Jixian; Ma, Fang

    2017-03-12

    The present study investigated effect of ammonium utilization on aerobic denitrification by Pseudomonas stutzeri T13. Per nitrogen balance calculation, all consumed ammonium was utilized as nitrogen source for cell propagation by assimilation rather than heterotrophic nitrification. Total organic carbon (TOC) and ammonium were necessary substrates to sustain heterotrophic propagation of P. stutzeri T13 at optimum proportion equal to seven. Under aerobic condition, nitrate was utilized as substitute nitrogen source when ammonium was completely exhausted. Biomass production effectively increased with increasing initial ammonium from 0mg/L to 100mg/L. Owing to enlarged biomass, average nitrate reduction rate increased from 7.36mgL(-1)h(-1) to 11.95mgL(-1)h(-1). Such process also successfully reduced nitrite accumulation from 121.8mg/L to 66.16mg/L during aerobic denitrification. As important accessory during aerobic denitrification, ammonium assimilation efficiently doubled total nitrogen (TN) removal from 54.97mg/L (no ammonium provided) to 113.1mg/L (100mg/L ammonium involved).

  11. Aerobic and anaerobic biosynthesis of nano-selenium for remediation of mercury contaminated soil.

    PubMed

    Wang, Xiaonan; Zhang, Daoyong; Pan, Xiangliang; Lee, Duu-Jong; Al-Misned, Fahad A; Mortuza, M Golam; Gadd, Geoffrey Michael

    2017-03-01

    Selenium (Se) nanoparticles are often synthesized by anaerobes. However, anaerobic bacteria cannot be directly applied for bioremediation of contaminated top soil which is generally aerobic. In this study, a selenite-reducing bacterium, Citrobacter freundii Y9, demonstrated high selenite reducing power and produced elemental nano-selenium nanoparticles (nano-Se(0)) under both aerobic and anaerobic conditions. The biogenic nano-Se(0) converted 45.8-57.1% and 39.1-48.6% of elemental mercury (Hg(0)) in the contaminated soil to insoluble mercuric selenide (HgSe) under anaerobic and aerobic conditions, respectively. Addition of sodium dodecyl sulfonate enhanced Hg(0) remediation, probably owing to the release of intracellular nano-Se(0) from the bacterial cells for Hg fixation. The reaction product after remediation was identified as non-reactive HgSe that was formed by amalgamation of nano-Se(0) and Hg(0). Biosynthesis of nano-Se(0) both aerobically and anaerobically therefore provides a versatile and cost-effective remediation approach for Hg(0)-contaminated surface and subsurface soils, where the redox potential often changes dramatically.

  12. Aerobic Capacity and Postprandial Flow Mediated Dilation.

    PubMed

    Ballard, Kevin D; Miller, James J; Robinson, James H; Olive, Jennifer L

    The consumption of a high-fat meal induces transient vascular dysfunction. Aerobic exercise enhances vascular function in healthy individuals. Our purpose was to determine if different levels of aerobic capacity impact vascular function, as measured by flow mediated dilation, following a high-fat meal. Flow mediated dilation of the brachial artery was determined before, two- and four-hours postprandial a high-fat meal in young males classified as highly trained (n = 10; VO2max = 74.6 ± 5.2 ml·kg·min(-1)) or moderately active (n = 10; VO2max = 47.3 ± 7.1 ml·kg·min(-1)). Flow mediated dilation was reduced at two- (p < 0.001) and four-hours (p < 0.001) compared to baseline for both groups but was not different between groups at any time point (p = 0.108). Triglycerides and insulin increased at two- (p < 0.001) and four-hours (p < 0.05) in both groups. LDL-C was reduced at four-hours (p = 0.05) in highly trained subjects, and two- and four-hours (p ≤ 0.01) in moderately active subjects. HDL-C decreased at two- (p = 0.024) and four-hours (p = 0.014) in both groups. Glucose increased at two-hours postprandial for both groups (p = 0.003). Our results indicate that a high-fat meal results in reduced endothelium-dependent vasodilation in highly trained and moderately active individuals with no difference between groups. Thus, high aerobic capacity does not protect against transient reductions in vascular function after the ingestion of a single high-fat meal compared to individuals who are moderately active.

  13. Screening and identification of aerobic denitrifiers

    NASA Astrophysics Data System (ADS)

    Shao, K.; Deng, H. M.; Chen, Y. T.; Zhou, H. J.; Yan, G. X.

    2016-08-01

    With the standards of the effluent quality more stringent, it becomes a quite serious problem for municipalities and industries to remove nitrogen from wastewater. Bioremediation is a potential method for the removal of nitrogen and other pollutants because of its high efficiency and low cost. Seven predominant aerobic denitrifiers were screened and characterized from the activated sludge in the CAST unit. Some of these strains removed 87% nitrate nitrogen at least. Based on their phenotypic and phylogenetic characteristics, the isolates were identified as the genera of Ralstonia, Achromobacter, Aeromonas and Enterobacter.

  14. Evidence that an internal carbonic anhydrase is present in 5% CO/sub 2/-grown and air-grown Chlamydomonas. [Chlamydomonas reinhardtii

    SciTech Connect

    Moroney, J.V.; Togasaki, R.K.; Husic, H.D.; Tolbert, N.E.

    1987-07-01

    Inorganic carbon (C/sub i/) uptake was measured in wild-type cells of Chlamydomonas reinhardtii, and in cia-3, a mutant strain of C. reinhardtii that cannot grow with air levels of CO/sub 2/. Both air-grown cells, that have a CO/sub 2/ concentrating system, and 5% CO/sub 2/-grown cells that do not have this system, were used. When the external pH was 5.1 or 7.3, air-grown, wild-type cells accumulated inorganic carbon (C/sub i/) and this accumulation was enhanced when the permeant carbonic anhydrase inhibitor, ethoxyzolamide, was added. When the external pH was 5.1, 5% CO/sub 2/-grown cells also accumulated some C/sub i/, although not as much as air-grown cells and this accumulation was stimulated by the addition of ethoxyzolamide. At the same time, ethoxyzolamide inhibited CO/sub 2/ fixation by high CO/sub 2/-grown, wild-type cells at both pH 5.1 and 7.3. These observations imply that 5% CO/sub 2/-grown, wild-type cells, have a physiologically important internal carbonic anhydrase, although the major carbonic anhydrase located in the periplasmic space is only present in air-grown cells. Inorganic carbon uptake by cia-3 cells supported this conclusion. This mutant strain, which is thought to lack an internal carbonic anhydrase, was unaffected by ethoxyzolamide at pH 5.1. Other physiological characteristics of cia-3 resemble those of wild-type cells that have been treated with ethoxyzolamide. It is concluded that an internal carbonic anhydrase is under different regulatory control than the periplasmic carbonic anhydrase.

  15. Effects of an esterase-producing inoculant on fermentation, aerobic stability, and neutral detergent fiber digestibility of corn silage.

    PubMed

    Kang, T W; Adesogan, A T; Kim, S C; Lee, S S

    2009-02-01