Sample records for vero cells grown

  1. Engineering Vero cells to secrete human insulin

    Microsoft Academic Search

    Lorraine O’Driscoll; Patrick Gammell; Martin Clynes

    2002-01-01

    Cell therapy may have the potential for the treatment of Type I diabetes. To date, cells suitable for this purpose have not been developed. This study investigates the feasibility of modifying Vero, a cell line that may be considered safe to implant into humans, for this purpose. Stable Vero transfectants containing full-length human preproinsulin complementary deoxyribonucleic acid (cDNA) were generated

  2. Cytotoxicity of butylated hydroxyanisole in Vero cells

    Microsoft Academic Search

    V. Labrador; P. Fernández Freire; J. M. Pérez Martín; M. J. Hazen

    2007-01-01

    Butylated hydroxyanisole (BHA) is perhaps the most extensively used synthetic antioxidant in the food and cosmetic industry,\\u000a although considerable controversy exists in the literature regarding the safety of this compound. Most in vitro studies describing the effects of BHA have been performed in cancer cells, but it is unclear whether normal cells are equally\\u000a susceptible to BHA exposure.\\u000a \\u000a The present

  3. Improved poliovirus D-antigen yields by application of different Vero cell cultivation methods.

    PubMed

    Thomassen, Yvonne E; Rubingh, Olaf; Wijffels, René H; van der Pol, Leo A; Bakker, Wilfried A M

    2014-05-19

    Vero cells were grown adherent to microcarriers (Cytodex 1; 3 g L(-1)) using animal component free media in stirred-tank type bioreactors. Different strategies for media refreshment, daily media replacement (semi-batch), continuous media replacement (perfusion) and recirculation of media, were compared with batch cultivation. Cell densities increased using a feed strategy from 1×10(6) cells mL(-1) during batch cultivation to 1.8, 2.7 and 5.0×10(6) cells mL(-1) during semi-batch, perfusion and recirculation, respectively. The effects of these different cell culture strategies on subsequent poliovirus production were investigated. Increased cell densities allowed up to 3 times higher D-antigen levels when compared with that obtained from batch-wise Vero cell culture. However, the cell specific D-antigen production was lower when cells were infected at higher cell densities. This cell density effect is in good agreement with observations for different cell lines and virus types. From the evaluated alternative culture methods, application of a semi-batch mode of operations allowed the highest cell specific D-antigen production. The increased product yields that can easily be reached using these higher cell density cultivation methods, showed the possibility for better use of bioreactor capacity for the manufacturing of polio vaccines to ultimately reduce vaccine cost per dose. Further, the use of animal-component-free cell- and virus culture media shows opportunities for modernization of human viral vaccine manufacturing. PMID:24583004

  4. VERO cells (cercopithecus aethiops kidney) — growth characteristics and viral susceptibility for use in diagnostic virology

    Microsoft Academic Search

    D. E. Macfarlane; R. G. Sommerville

    1969-01-01

    Summary An investigation of some of the characteristics of the VERO cell line (Cercopithecus aethiops kidney) is reported, in which the suitability of the cells for use in routine diagnostic virology was examined. VERO cells will:1.grow to monolayers as rapidly as other heteroploid cell lines, but will maintain as usable monolayers in conventional maintenance medium for a significantly longer time;2.grow

  5. Proteomic Analysis of Membrane Proteins of Vero Cells: Exploration of Potential Proteins Responsible for Virus Entry

    PubMed Central

    Guo, Donghua; Zhu, Qinghe; Zhang, Hong

    2014-01-01

    Vero cells are highly susceptible to many viruses in humans and animals, and its membrane proteins (MPs) are responsible for virus entry. In our study, the MP proteome of the Vero cells was investigated using a shotgun LC-MS/MS approach. Six hundred twenty-seven proteins, including a total of 1839 peptides, were identified in MP samples of the Vero cells. In 627 proteins, 307 proteins (48.96%) were annotated in terms of biological process of gene ontology (GO) categories; 356 proteins (56.78%) were annotated in terms of molecular function of GO categories; 414 proteins (66.03%) were annotated in terms of cellular components of GO categories. Of 627 identified proteins, seventeen proteins had been revealed to be virus receptor proteins. The resulting protein lists and highlighted proteins may provide valuable information to increase understanding of virus infection of Vero cells. PMID:24286161

  6. The Genome Landscape of the African Green Monkey Kidney-Derived Vero Cell Line

    PubMed Central

    Osada, Naoki; Kohara, Arihiro; Yamaji, Toshiyuki; Hirayama, Noriko; Kasai, Fumio; Sekizuka, Tsuyoshi; Kuroda, Makoto; Hanada, Kentaro

    2014-01-01

    Continuous cell lines that originate from mammalian tissues serve as not only invaluable tools for life sciences, but also important animal cell substrates for the production of various types of biological pharmaceuticals. Vero cells are susceptible to various types of microbes and toxins and have widely contributed to not only microbiology, but also the production of vaccines for human use. We here showed the genome landscape of a Vero cell line, in which 25,877 putative protein-coding genes were identified in the 2.97-Gb genome sequence. A homozygous ?9-Mb deletion on chromosome 12 caused the loss of the type I interferon gene cluster and cyclin-dependent kinase inhibitor genes in Vero cells. In addition, an ?59-Mb loss of heterozygosity around this deleted region suggested that the homozygosity of the deletion was established by a large-scale conversion. Moreover, a genomic analysis of Vero cells revealed a female Chlorocebus sabaeus origin and proviral variations of the endogenous simian type D retrovirus. These results revealed the genomic basis for the non-tumourigenic permanent Vero cell lineage susceptible to various pathogens and will be useful for generating new sub-lines and developing new tools in the quality control of Vero cells. PMID:25267831

  7. The genome landscape of the african green monkey kidney-derived vero cell line.

    PubMed

    Osada, Naoki; Kohara, Arihiro; Yamaji, Toshiyuki; Hirayama, Noriko; Kasai, Fumio; Sekizuka, Tsuyoshi; Kuroda, Makoto; Hanada, Kentaro

    2014-12-01

    Continuous cell lines that originate from mammalian tissues serve as not only invaluable tools for life sciences, but also important animal cell substrates for the production of various types of biological pharmaceuticals. Vero cells are susceptible to various types of microbes and toxins and have widely contributed to not only microbiology, but also the production of vaccines for human use. We here showed the genome landscape of a Vero cell line, in which 25,877 putative protein-coding genes were identified in the 2.97-Gb genome sequence. A homozygous ?9-Mb deletion on chromosome 12 caused the loss of the type I interferon gene cluster and cyclin-dependent kinase inhibitor genes in Vero cells. In addition, an ?59-Mb loss of heterozygosity around this deleted region suggested that the homozygosity of the deletion was established by a large-scale conversion. Moreover, a genomic analysis of Vero cells revealed a female Chlorocebus sabaeus origin and proviral variations of the endogenous simian type D retrovirus. These results revealed the genomic basis for the non-tumourigenic permanent Vero cell lineage susceptible to various pathogens and will be useful for generating new sub-lines and developing new tools in the quality control of Vero cells. PMID:25267831

  8. Development of a Vero cell DNA reference standard for residual DNA measurement in China

    PubMed Central

    Cao, Shouchun; Dong, Guanmu; Tang, Jianrong; Li, Jia; Liu, Jinghua; Shi, Leitai; Li, Changgui; Wang, Junzhi

    2013-01-01

    This collaborative study developed a Vero cell DNA reference for standardizing dot blot hybridization, an assay widely employed to measure residual DNA contents of viral vaccines prepared with Vero cells. High purity of Vero cell DNA was extracted and characterized by Hind III enzyme digestion and DNA sequencing. Then, with a cooperative calibration, the concentration of Vero cell DNA reference bulk solution was determined (64.0 ± 1.9 ?g/mL, OD260/OD280 = 1.87) and diluted (40 ng/mL) with Tris-EDTA buffer containing bovine serum albumin as freeze-dried excipients. With industrial filling apparatus, the diluted bulk was loaded into ampoules (0.5 mL each) which were heat sealed after nitrogen filling. Finally, a collaborative study showed that the Vero cell DNA reference could reach a sensitivity of 1 to 5 pg/dot and maintained good stability after accelerated destruction test. The successful establishment of the Vero cell DNA quantitative reference will facilitate the standardization of dot blot hybridization for testing residual host cell DNA. PMID:23291952

  9. Purification of diphtheria toxin receptor from Vero cells.

    PubMed

    Mekada, E; Senoh, H; Iwamoto, R; Okada, Y; Uchida, T

    1991-10-25

    Diphtheria toxin receptor has been solubilized from Vero cell membranes with octyl beta-D-glucoside. CRM197, the product of a mutated diphtheria toxin gene, was used for the identification of the receptor. The binding activity of the solubilized receptor was assayed by precipitating the receptor with acetone in the presence of phospholipids and carrier proteins. The solubilized receptor was purified by the combination of several chromatographic steps in the presence of the detergent, resulting in about a 10(6)-fold purification of the receptor. The purified receptor showed essentially a single band of 14.5 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. When partially purified receptor fractions were subjected to ligand blotting analysis using 125I-CRM197 as the probe, the 14.5-kDa protein and a few minor protein bands were identified as diphtheria toxin-binding molecules. These results show clearly that the 14.5-kDa protein is the diphtheria toxin receptor, or at least the major diphtheria toxin-binding molecule. When partially purified receptor was applied to a Sephacryl S-300 column in the presence of detergent, the receptor was eluted in the fractions corresponding to the 60-90-kDa size range. This suggests that the protein forms a complex with itself or with another protein. PMID:1939100

  10. A Vero-cell-adapted vaccine donor strain of influenza A virus generated by serial passages.

    PubMed

    Hu, Weibin; Zhang, Hong; Han, Qinglin; Li, Li; Chen, Yixin; Xia, Ningshao; Chen, Ze; Shu, Yuelong; Xu, Ke; Sun, Bing

    2015-01-01

    A cell culture-based vaccine production system is preferred for the large-scale production of influenza vaccines and has advantages for generating vaccines against highly pathogenic influenza A viruses. Vero cells have been widely used in human vaccine manufacturing, and the safety of these cells has been well demonstrated. However, the most commonly used influenza-vaccine donor virus, A/Puerto Rico/8/1934 (PR8) virus, does not grow efficiently in Vero cells. Therefore, we adapted the PR8 virus to Vero cells by continuous passaging, and a high-growth strain was obtained after 20 passages. Sequence analysis and virological assays of the adapted strain revealed that mutations in four viral internal genes (NP, PB1, PA and NS1) were sufficient for adaptation. The recombinant virus harboring these mutations (PR8-4mut) displayed accelerated viral transport into the nucleus and increased RNP activity. Importantly, the PR8-4mut could serve as a backbone donor virus to support the growth of the H7N1, H9N2 and H5N1 avian viruses and the H1N1 and H3N2 human viruses in Vero cells without changing its pathogenicity in either chicken embryos or mice. Thus, our work describes the generation of a Vero-adapted, high-yield PR8-4mut virus that may serve as a promising candidate for an influenza-vaccine donor virus. PMID:25448099

  11. Changes in antiviral susceptibility to entry inhibitors and endocytic uptake of dengue-2 virus serially passaged in Vero or C6/36 cells.

    PubMed

    Acosta, Eliana G; Piccini, Luana E; Talarico, Laura B; Castilla, Viviana; Damonte, Elsa B

    2014-05-12

    The aim of the present study was to analyze the influence of virus origin, mammalian or mosquito cell-derived, on antiviral susceptibility of DENV-2 to entry inhibitors and the association of this effect with any alteration in the mode of entry into the cell. To this end, ten serial passages of DENV-2 were performed in mosquito C6/36 cells or monkey Vero cells and the antiviral susceptibility of each virus passage to sulfated polysaccharides (SPs), like heparin and carrageenans, was evaluated by a virus plaque reduction assay. After serial passaging in Vero cells, DENV-2 became increasingly resistant to SP inhibition whereas the antiviral susceptibility was not altered in virus propagated in C6/36 cells. The change in antiviral susceptibility was associated to a differential mode of entry into the host cell. The route of endocytic entry for productive Vero cell infection was altered from a non-classical clathrin independent pathway for C6/36-grown virus to a clathrin-mediated endocytosis when the virus was serially propagated in Vero cells. Our results show the impact of the cellular system used for successive propagation of DENV on the initial interaction between the host cell and the virion in the next round of infection and the relevant consequences it might have during the in vitro evaluation of entry inhibitors. PMID:24583230

  12. Leucine affects the fibroblastic Vero cells stimulating the cell proliferation and modulating the proteolysis process

    Microsoft Academic Search

    Estela Maria Gonçalves; Maria Cristina Cintra Gomes-Marcondes

    2010-01-01

    Branched-chain amino acids, especially leucine, exert regulatory influences on protein and carbohydrate metabolism, ribosome\\u000a biogenesis and gene expression. This study investigated the effects of leucine in fibroblastic cells analysing viability,\\u000a proliferation, morphology, proteolysis enzymes activities and protein turnover. After exposure to culture medium enriched\\u000a with 25 or 50 ?M leucine for 24, 48 and 72 h, Vero cells have no alterations on

  13. Isolation and propagation of Dengue virus in Vero and BHK-21 cells expressing human DC-SIGN stably.

    PubMed

    Phanthanawiboon, Supranee; A-nuegoonpipat, Atchareeya; Panngarm, Narawan; Limkittikul, Kriengsak; Ikuta, Kazuyoshi; Anantapreecha, Surapee; Kurosu, Takeshi

    2014-12-01

    The "standard" methods of isolating dengue virus (DENV) utilize the mosquito cell line C6/36, monkey kidney LLC-MK2 cells, Vero cells, or baby hamster kidney (BHK-21) cells. However, these cells lines lack a particular DENV receptor, known as dendritic cell-specific ICAM-3-grabbing non-integrin (DC-SIGN), which is expressed on immature dendritic cells and monocytes/macrophages. This may result in less efficient virus isolation and propagation. The present study used a lentivirus vector to establish Vero and BHK-21 cell lines (Vero-DC and BHK-DC) that express human DC-SIGN stably. Five DENV strains, each passaged several times in C6/36 cells, replicated more efficiently in Vero-DC and BHK-DC than in the parental Vero or BHK-21 cells. Vero/Vero-DC and BHK-21/BHK-DC were used to isolate virus from buffy coats and plasma samples derived from 13 patients infected with DENV. Most of the viruses showed increased production in cell lines expressing DC-SIGN. However, the isolation rate was lower (15.4-46.2%) than that from C6/36 cells (84.6%). Interestingly, when the viruses were isolated in C6/36 cells prior to infecting Vero/Vero-DC and BHK-21/BHK-DC, the rate of virus production increased markedly, reaching levels higher than those initially achieved in C6/36 cells. These data suggest that Vero-DC and BHK-DC could be useful tools for virus propagation, and that human specimens may contain a factor that interferes with virus growth in mammalian cells. PMID:25205264

  14. Cytotoxic effects of etephon and maleic hydrazide in Vero, Hep2, HepG2 cells.

    PubMed

    Yurdakok, Begum; Baydan, Emine; Okur, Hamza; Gurcan, Ismayil Safa

    2014-10-01

    The toxicity of etephon and maleic hydrazide, used as plant growth regulators in agriculture, were reported as low in mammals in previous studies. However, in vitro cytotoxicity studies in mammalian cells are currently missing to understand their toxicity at molecular level. In the current study, the cytotoxicity of these compounds, were studied in Vero (African green monkey kidney epithelium), HepG2 (human hepatocellular carcinoma), Hep2 (human epidermoid cancer) cells by MTT ((3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazolium bromure) and LDH (lactate dehydrogenase) assays. Maleic hydrazide had lower IC50 values for all cell lines compared to ethephon. Least cytotoxic effect treated by ethephon were observed in Vero, followed by HepG2 and Hep2. Similarly maleic hydrazide also showed least cytotoxicity on Vero cells, followed by Hep2 and HepG2 cells (p?Vero cells, followed by HepG2 and Hep2 cells (p?0.868 (p?cells to be supplemented by further studies. PMID:24495230

  15. Establishment of an analyzing method for a Japanese encephalitis virus neutralization test in Vero cells

    Microsoft Academic Search

    Motoharu Abe; Syoji Kuzuhara; Yoichiro Kino

    2003-01-01

    We established a 50% plaque reduction analyzing method of neutralizing antibody for human serum to Japanese encephalitis virus (JEV) in Vero cells, called the ‘3 points least-squares regression method’ (3LSRM). Our method shows a high correlation with the chick embryo cell method (the current standard method for human serum), using the chart method established by the National Institute of Infectious

  16. Oral efficacy of Vero cell attenuated porcine epidemic diarrhea virus DR13 strain

    Microsoft Academic Search

    D. S. Song; J. S. Oh; B. K. Kang; J. S. Yang; H. J. Moon; H. S. Yoo; Y. S. Jang; B. K. Park

    2007-01-01

    A Vero cell attenuated porcine epidemic diarrhea virus (PEDV) strain, DR13, was distinguished from wild-type PEDV using restriction enzyme fragment length polymorphism (RFLP). Cell attenuated DR13 was orally or intramuscularly (IM) administered to late-term pregnant sows, and mortality resulting from the highly virulent PEDV challenge was investigated in passively immunized suckling piglets of the two different groups. The mortality rate

  17. Oral efficacy of Vero cell attenuated porcine epidemic diarrhea virus DR13 strain

    Microsoft Academic Search

    D. S. Song; J. S. Oh; B. K. Kang; J. S. Yang; H. J. Moon; H. S. Yoo; Y. S. Jang; B. K. Park

    2006-01-01

    A Vero cell attenuated porcine epidemic diarrhea virus (PEDV) strain, DR13, was distinguished from wild-type PEDV using restric- tion enzyme fragment length polymorphism (RFLP). Cell attenuated DR13 was orally or intramuscularly (IM) administered to late-term pregnant sows, and mortality resulting from the highly virulent PEDV challenge was investigated in passively immunized suckling piglets of the two different groups. The mortality

  18. Formation of varicella-zoster virus antigens in infected Vero cells.

    PubMed

    Takayama, M; Oya, A

    1985-01-01

    The formation of varicella-zoster (V-Z) virus-associated antigens was studied in V-Z virus-infected Vero cells by means of indirect immunofluorescence. Early antigen (EA) was first detected inside V-Z virus-infected Vero cells 4 to 6 hr after infection, whereas surface membrane antigen (SMA) was expressed on the outer surface of infected cells 2 to 3 hr later than EA, and intranuclear late antigen (LA) was detected several hours later than SMA antigen. EA expression was not inhibited by cytosine arabinoside (Ara-C) treatment, whereas LA formation was completely blocked by Ara-C. The presence of two components of SMA early SMA (ESMA) and late SMA (LSMA), was suggested by this difference in susceptibility to Ara-C. The formation of all viral antigens, EA, SMA, and LA, was blocked by inhibitors of RNA and protein synthesis. PMID:3003545

  19. Equine herpes virus type 1 (EHV-1) infection induces alterations in the cytoskeleton of vero cells but not apoptosis.

    PubMed

    Walter, I; Nowotny, N

    1999-01-01

    Effects of infection with two different strains of equine herpes virus type 1 (EHV-1; Piber 178/83, Kentucky D) on the cytoskeleton of Vero cells were investigated immunohistochemically, and evaluated by confocal laser scanning microscopy. Twenty four hours post EHV-1 infection the assembly of the microtubulus system of Vero cells was heavily disturbed. The Golgi region was dispersed into vesicles spread throughout the cytoplasm as demonstrated by WGA lectin binding. Other cytoskeletal elements such as cytokeratin, vimentin, and filamentous actin (F-actin) were not affected by EHV-1 infection. The nature of Vero cell death after EHV-1 infection was investigated by three different methods to include all possible stages of apoptosis. All methods failed to demonstrate characteristic apoptotic features, therefore, it seems likely that necrosis is the predominant way of cell death in EHV-1 infected Vero cells. PMID:10542029

  20. Uropathogenic Escherichia coli isolates with different virulence genes content exhibit similar pathologic influence on Vero cells.

    PubMed

    Obaid, Jamil M A S; Mansour, Samira R; Elshahedy, Mohammed S; Rabie, Tarik E; Azab, Adel M H

    2014-01-01

    Uropathogenic Escherichia coli are the major causative agent of urinary tract infection--they may simultaneously express a number of virulence factors to cause disease. The aim of this study was to investigate the relation between virulence factors content of fifteen UPEC isolates and their pathogenic potential. The isolates belonged to the five serotypes O78:K80, O114:K90, O142:K86, O164 and O157. Nine of the virulence factors have been explored, ibeA, pap, sfa/foc, cnfl, hly, fyuA, pil, ompT and traT. Virulence factors profiling of the isolates revealed a different content ranging from 22% to 100% of the virulence genes explored. The pathogenic capacity of all fifteen isolates when tested on Vero cells showed that the cytotoxicity for all tested strains on Vero cells was approximately equal and enhanced after growth in syncase broth, leading mainly to cell lysis. The toxic effects reduced slightly after heat treatment of the toxin, and greatly after formalin detoxification, but not all the deleterious effect was abolished. Endotoxin also has cytotoxic effects on Vero cells, but longer time is needed for cytolysis which is greatly diminished with formalin treatment. In conclusion, our study revealed that pathogenic strains of UPEC can exert their pathogenic effect on live cells or system with limited virulence factors gene content. PMID:25033661

  1. Vero cell assay validation of an alternative to the Ph. Eur. diphtheria potency tests.

    PubMed

    Gommer, A M

    1996-01-01

    In the framework of the Biological Standardisation Programme of the European Pharmacopoeia Commission, in 1993 a collaborative study was organised for the validation of an alternative to the diphtheria in vivo challenge tests required by the Ph.Eur. monograph V.2.2.7. The alternative assay is based on the detection of neutralising antibodies in the sera from mice immunised with the vaccines to be tested (Vero cell assay). In the study this assay method was validated against intradermal and lethal challenge in guinea-pigs, performed in conformity with Ph.Eur. Therefore the potency currently on the European market, was assayed in parallel by the different assay methods. Seventeen laboratories, from eleven different countries, participated in the study. Three laboratories performed the intradermal challenge assay, while three other laboratories performed the lethal challenge assay. All seventeen laboratories performed the Vero cell assay. The results of the study suggest that the potency of the diphtheria component of both monovalent diphtheria vaccines and combined diphtheria-tetanus vaccines can be estimated adequately by means of the Vero cell assay. It does not yet seem possible for all combined diphtheria-tetanus-pertussis vaccines to replace a potency assay based on the protective capacity of a vaccine in guinea-pigs by the Vero cell assay. This may be due to an adjuvant effect of the pertussis component of the vaccine, in combination with the adsorbent used, which may be more pronounced in mice than in guinea-pigs and may also differ between different strains of mice. PMID:8785952

  2. Equine herpes virus type 1 (EHV1) infection induces alterations in the cytoskeleton of Vero cells but not apoptosis

    Microsoft Academic Search

    I. Walter; N. Nowotny

    1999-01-01

    Summary.  ?Effects of infection with two different strains of equine herpes virus type 1 (EHV-1; Piber 178\\/83, Kentucky D) on the cytoskeleton\\u000a of Vero cells were investigated immunohistochemically, and evaluated by confocal laser scanning microscopy. Twenty four hours\\u000a post EHV-1 infection the assembly of the microtubulus system of Vero cells was heavily disturbed. The Golgi region was dispersed\\u000a into vesicles spread

  3. Extremely low-frequency electromagnetic fields cause DNA strand breaks in normal Vero cells

    E-print Network

    Cosmin Teodor Miha; Gabriela Vochita; Florin Brinza; Pincu Rotinberg

    2013-01-23

    Extremely low frequency electromagnetic fields aren't considered as a real carcinogenic agent despite the fact that some studies have showed impairment of the DNA integrity in different cells lines. The aim of this study was evaluation of the late effects of a 100 Hz and 5.6 mT electromagnetic field, applied continuously or discontinuously, on the DNA integrity of Vero cells assessed by alkaline Comet assay and by cell cycle analysis. Normal Vero cells were exposed to extremely low frequency electromagnetic fields (100 Hz, 5.6 mT) for 45 minutes. The Comet assay and cell cycle analysis were performed 48 hours after the treatment. Exposed samples presented an increase of the number of cells with high damaged DNA as compared with non-exposed cells. Quantitative evaluation of the comet assay showed a significantly ($cells. Cell cycle analysis showed an increase of the frequency of the cells in S phase, proving the occurrence of single strand breaks. The most probable mechanism of induction of the registered effects is the production of different types of reactive oxygen species.

  4. [A study of the antiherpetic activity of the chaga mushroom (Inonotus obliquus) extracts in the Vero cells infected with the herpes simplex virus].

    PubMed

    Polkovnikova, M V; Nosik, N N; Garaev, T M; Kondrashina, N G; Finogenova, M P; Shibnev, V A

    2014-01-01

    The chaga mushroom (Inonotus obliquus) contains a wide range of excellent bioactive compounds. However, limited information exists on the antiviral activity of the compounds extracted from chaga. A number of subfractions of chaga were obtained using different solvents and different procedures. The subfractions of chaga extracted with water, alcohol, alkali were tested for their toxicity for the Vero cell culture and antiviral effect in the Vero cells infected with the Herpes simplex virus (HSV), Type 1. It was shown that most of the subfractions were not toxic for the Vero cells and had protective effect on the Vero cells infected with HSV. The subfraction IV in the concentration 5 microg/ml protected the Vero cells from cytodestructive action of HSV and no viral DNA was detected in infected cells treated with chaga extracts. Best protective effect was observed when compound was added before or within one hour after the Vero cells were infected with HSV. PMID:25069286

  5. Adaptation and growth kinetics study of an Indian isolate of virulent duck enteritis virus in Vero cells.

    PubMed

    Aravind, S; Kamble, Nitin M; Gaikwad, Satish S; Shukla, Sanjeev Kumar; Dey, Sohini; Mohan, C Madhan

    2015-01-01

    Duck virus enteritis, also known as duck plague, is a viral infection of ducks caused by duck enteritis virus (DEV). The control of the disease is mainly done by vaccination with chicken embryo adapted live virus that is known to be poorly immunogenic and elicits only partial protection. Further, the embryo propagated vaccine virus pose a threat of harboring other infectious agents. Seeing these limitations, the present study reports for the first time regarding propagation and adaptation of a virulent Indian isolate of duck enteritis virus in Vero cell line. In this study isolation of an outbreak virus from Kerala state was done in chicken embryo fibroblast cell culture (CEF). Then adapted the DEV isolate in the Vero cell line. The characteristic cytopathic effects (CPE) of clumping and fusion of Vero cells were observed starting from the 7th passage onwards. The presence of the virus and its multiplication in Vero cells was confirmed by detection of viral specific DNA and antigen by using polymerase chain reaction (PCR) and indirect immuno fluorescent assay (IIFA), respectively. PCR detection of DEV using self designed primers for US4 (gD) and UL30 (DNA Polymerase) gene has been reported for the in the present study. The kinetics of DEV in Vero cells revealed a maximum infectivity titer of 10(5.6) TCID 50/ml after 48hr of viral infection. Compared to chicken embryo adapted DVE vaccine virus, the Vero cell culture system is free from other infectious agents. So it will be a good candidate for cultivation and propagation of duck enteritis virus vaccine strain. Further research studies are suggested to explore the feasibility of utilizing this Vero cell culture adapted DEV isolate for developing an attenuated vaccine virus against duck virus enteritis. PMID:25450886

  6. Removing residual DNA from Vero-cell culture-derived human rabies vaccine by using nuclease.

    PubMed

    Li, Si-Ming; Bai, Fu-Liang; Xu, Wen-Juan; Yang, Yong-Bi; An, Ying; Li, Tian-He; Yu, Yin-Hang; Li, De-Shan; Wang, Wen-Fei

    2014-09-01

    The clearance of host cell DNA is a critical indicator for Vero-cell culture-derived rabies vaccine. In this study, we evaluated the clearance of DNA in Vero-cell culture-derived rabies vaccine by purification process utilizing ultrafiltration, nuclease digestion, and gel filtration chromatography. The results showed that the bioprocess of using nuclease decreased residual DNA. Dot-blot hybridization analysis showed that the residual host cell DNA was <100 pg/ml in the final product. The residual nuclease in rabies vaccine was less than 0.1 ng/ml protein. The residual nuclease could not paly the biologically active role of digestion of DNA. Experiments of stability showed that the freeze-drying rabies virus vaccine was stable and titers were >5.0 IU/ml. Immunogenicity test and protection experiments indicated mice were greatly induced generation of neutralizing antibodies and invoked protective effects immunized with intraperitoneal injections of the rabies vaccine. These results demonstrated that the residual DNA was removed from virus particles and nuclease was removed by gel filtration chromatography. The date indicated that technology was an efficient method to produce rabies vaccine for human use by using nuclease. PMID:25108516

  7. Hantaviruses and TNF-alpha act synergistically to induce ERK1\\/2 inactivation in Vero E6 cells

    Microsoft Academic Search

    Tomas Strandin; Jussi Hepojoki; Hao Wang; Antti Vaheri; Hilkka Lankinen

    2008-01-01

    BACKGROUND: We have previously reported that the apathogenic Tula hantavirus induces apoptosis in Vero E6 epithelial cells. To assess the molecular mechanisms behind the induced apoptosis we studied the effects of hantavirus infection on cellular signaling pathways which promote cell survival. We previously also observed that the Tula virus-induced cell death process is augmented by external TNF-?. Since TNF-? is

  8. Development of a Vero cell-derived influenza whole virus vaccine.

    PubMed

    Kistner, O; Barrett, P N; Mundt, W; Reiter, M; Schober-Bendixen, S; Eder, G; Dorner, F

    1999-01-01

    Influenza vaccine production is dependent on the availability of embryonated hen eggs for virus growth. This is an extremely cumbersome system with many disadvantages with respect to selection of virus variants and the presence of adventitious viruses. We have developed an alternative cell culture system which allows rapid production of large volumes of vaccine. The WHO-approved Vero cell line was used in serum-free culture to grow many influenza strains to high titre. This system could be scaled-up to allow vaccine production with a 1200 litre fermenter. A purification scheme was developed which resulted in a high purity whole virus vaccine. This was demonstrated to be at least as immunogenic as a conventional egg-derived preparation. PMID:10494963

  9. Development of a mammalian cell (Vero) derived candidate influenza virus vaccine.

    PubMed

    Kistner, O; Barrett, P N; Mundt, W; Reiter, M; Schober-Bendixen, S; Dorner, F

    1998-01-01

    Influenza vaccine production is dependent on the availability of embryonated hen eggs for virus growth. This is an extremely cumbersome system with many disadvantages with respect to selection of virus variants and presence of adventitious viruses. We have developed an alternative cell culture system which allows rapid production of large volumes of vaccine. The World Health Organisation (WHO) approved Vero cell line was used in serum-free culture to grow a multitude of influenza strains to high titre. This system could be scaled-up to allow vaccine production with a 1200 litre fermenter volume. A purification scheme was developed which resulted in a high purity whole virus vaccine. This was demonstrated to be at least as immunogenic as a conventional egg-derived preparation in a mouse model. PMID:9682344

  10. Photoirradiation study of gold nanospheres and rods in Vero and Hela cell lines

    NASA Astrophysics Data System (ADS)

    Gananathan, Poorani; Aruna, Prakasarao; Ganesan, Singaravelu; Elanchezhiyan, Manickan

    2014-03-01

    Photoirradiation effect of gold nanospheres in conjucation with green light and rods in conjugation with red light corresponds to their absorption wavelength range found to be appreciable. In this present work concentration of nanomaterial and light dose were optimized. Gold nanospheres were synthesized by reduction technique using Sodium Borohydrate as reducing agent and Trisodium Citrate as capping agent. Au nanorods having 680-900nm absorption were synthesized using reduction techniques with CTAB and BDAC polymers. From UV-Vis absorption and Transmission Electron Microscopy the size of nanoparticles were confirmed. 30nm Gold nanospheres and green light source of 530nm wavelength with power 30mW were applied to Vero and Hela cell lines shows higher toxicity for Hela cells. Nanorods were applied and irradiated with 680nm wavelength light source with light intensity 45mW. Post irradiation effect for 24hrs, 48hrs confirms cell proliferation in normal rate in viable cells. The morphological changes in irradiated spot leads to apoptotoic cell death was confirmed with microscopic imaging. The LD50 value was also calculated.

  11. VERO cells harbor a poly-ADP-ribose belt partnering their epithelial adhesion belt

    PubMed Central

    Vilchez Larrea, Salomé C.; Kun, Alejandra

    2014-01-01

    Poly-ADP-ribose (PAR) is a polymer of up to 400 ADP-ribose units synthesized by poly-ADP-ribose-polymerases (PARPs) and degraded by poly-ADP-ribose-glycohydrolase (PARG). Nuclear PAR modulates chromatin compaction, affecting nuclear functions (gene expression, DNA repair). Diverse defined PARP cytoplasmic allocation patterns contrast with the yet still imprecise PAR distribution and still unclear functions. Based on previous evidence from other models, we hypothesized that PAR could be present in epithelial cells where cadherin-based adherens junctions are linked with the actin cytoskeleton (constituting the adhesion belt). In the present work, we have examined through immunofluorescence and confocal microscopy, the subcellular localization of PAR in an epithelial monkey kidney cell line (VERO). PAR was distinguished colocalizing with actin and vinculin in the epithelial belt, a location that has not been previously reported. Actin filaments disruption with cytochalasin D was paralleled by PAR belt disruption. Conversely, PARP inhibitors 3-aminobenzamide, PJ34 or XAV 939, affected PAR belt synthesis, actin distribution, cell shape and adhesion. Extracellular calcium chelation displayed similar effects. Our results demonstrate the existence of PAR in a novel subcellular localization. An initial interpretation of all the available evidence points towards TNKS-1 as the most probable PAR belt architect, although TNKS-2 involvement cannot be discarded. Forthcoming research will test this hypothesis as well as explore the existence of the PAR belt in other epithelial cells and deepen into its functional implications. PMID:25332845

  12. Evaluation of antiviral activities of curcumin derivatives against HSV-1 in Vero cell line.

    PubMed

    Zandi, Keivan; Ramedani, Elissa; Mohammadi, Khosro; Tajbakhsh, Saeed; Deilami, Iman; Rastian, Zahra; Fouladvand, Moradali; Yousefi, Forough; Farshadpour, Fatemeh

    2010-12-01

    Antiviral drug resistance is one of the most common problems in medicine, and, therefore, finding new antiviral agents, especially from natural resources, seems to be necessary. This study was designed to assay the antiviral activity of curcumin and its new derivatives like gallium-curcumin and Cu-curcumin on replication of HSV-1 in cell culture. The research was performed as an in vitro study in which the antiviral activity of different concentrations of three substances including curcumin, Gallium-curcumin and Cu-curcumin were tested on HSV-1. The cytotoxicity of the tested compounds was also evaluated on the Vero cell line. The CC50 values for curcumin, gallium-curcumin and Cu-curcumin were 484.2 microg/mL, 255.8 microg/mL and 326.6 microg/mL, respectively, and the respective IC50 values 33.0 microg/mL, 13.9 microg/mL and 23.1 microg/mL. The calculated SI values were 14.6, 18.4 and 14.1, respectively. The results showed that curcumin and its new derivatives have remarkable antiviral effects on HSV-1 in cell culture. PMID:21299124

  13. The 3a Protein of SARS-coronavirus Induces Apoptosis in Vero E6 Cells.

    PubMed

    Y Waye, Mary; W Law, Patrick; Wong, Chi-Hang; C Au, Thomas; Chuck, Chi-Pang; Kong, Siu-Kai; S Chan, Paul; To, Ka-Fai; I Lo, Anthony; W Chan, Judy; Suen, Yick-Keung; Edwin Chan, H Y; Fung, Kwok-Pui; Y Sung, Joseph; Lo, Y M; W Tsui, Stephen

    2005-01-01

    An outbreak of severe acute respiratory syndrome (SARS) occurred in China and the first case emerged in mid November 2002. The etiologic agent of this disease was found to be a previously unknown coronavirus, SARS-CoV. The detailed pathology of SARS-CoV infection and the host response to the viral infection are still not known. The 3a gene encodes a non-structural viral protein which is predicted to be a transmembrane protein. In this study, we showed that the 3a protein was localized to the endoplasmic reticulum (ER) in 3a-transfected monkey kidney Vero E6 cells. In vitro experiments of chromatin condensation and DNA fragmentation suggest that the 3a protein may trigger apoptosis. Our data show that over-expression of a single SARS-CoV protein can induce apoptosis in vitro. Thus GFP-3a fusion protein could also be used as a biosensor for monitoring the cytopathic features of SARS infection, e.g. lymphopenia, in animal model systems, similar to nucleocapsid and 7a proteins. PMID:17282011

  14. Comparison of herpes simplex (HSV) proteins synthesized in Vero, HEP-2 and human megakaryocyte-like cell lines

    SciTech Connect

    Soslau, G.; Pastorino, M.B.; Morgan, D.A.; Brodsky, I.; Howett, M.K.

    1986-05-01

    The natural human host blood cell capable of supporting herpes virus replication has yet to be defined. They found that a recently cultured human megakaryocyte-like (Meg) cell line can support HSV 1 and 2 replication as demonstrated by growth inhibition, CPE, virus production and HSV DNA synthesis. The HSV proteins synthesized and post-translationally modified in Vero and HEp-2 infected cells were compared to the protein species produced in the infected Meg cell since differences may influence antigenic properties and host range. Host cell protein synthesis was greatly reduced in all three cell lines within hours post infection (pi). However, maximum viral protein synthesis occurs between 4 and 24 hrs pi with the Meg cells as compared to 24-48 hrs pi with the other cell lines. The immunoprecipitated /sup 35/S-methionine labeled HSV protein gel patterns for each infected cell line are qualitatively and quantitatively very different from each other. Dramatic differences were also observed when infected cells were labeled with /sup 32/P-ATP (in vitro method) or /sup 32/Pi (in vivo method). Finally, analysis of /sup 3/H-mannose labeled HSV glycoproteins demonstrates that the post-translational modifications of these proteins are significantly altered in the Meg cell as compared to the Vero and HEp-2 cells.

  15. Serum-free microcarrier based production of replication deficient Influenza vaccine candidate virus lacking NS1 using Vero cells

    PubMed Central

    2011-01-01

    Background Influenza virus is a major health concern that has huge impacts on the human society, and vaccination remains as one of the most effective ways to mitigate this disease. Comparing the two types of commercially available Influenza vaccine, the live attenuated virus vaccine is more cross-reactive and easier to administer than the traditional inactivated vaccines. One promising live attenuated Influenza vaccine that has completed Phase I clinical trial is deltaFLU, a deletion mutant lacking the viral Nonstructural Protein 1 (NS1) gene. As a consequence of this gene deletion, this mutant virus can only propagate effectively in cells with a deficient interferon-mediated antiviral response. To demonstrate the manufacturability of this vaccine candidate, a batch bioreactor production process using adherent Vero cells on microcarriers in commercially available animal-component free, serum-free media is described. Results Five commercially available animal-component free, serum-free media (SFM) were evaluated for growth of Vero cells in agitated Cytodex 1 spinner flask microcarrier cultures. EX-CELL Vero SFM achieved the highest cell concentration of 2.6 × 10^6 cells/ml, whereas other SFM achieved about 1.2 × 10^6 cells/ml. Time points for infection between the late exponential and stationary phases of cell growth had no significant effect in the final virus titres. A virus yield of 7.6 Log10 TCID50/ml was achieved using trypsin concentration of 10 ?g/ml and MOI of 0.001. The Influenza vaccine production process was scaled up to a 3 liter controlled stirred tank bioreactor to achieve a cell density of 2.7 × 10^6 cells/ml and virus titre of 8.3 Log10 TCID50/ml. Finally, the bioreactor system was tested for the production of the corresponding wild type H1N1 Influenza virus, which is conventionally used in the production of inactivated vaccine. High virus titres of up to 10 Log10 TCID50/ml were achieved. Conclusions We describe for the first time the production of Influenza viruses using Vero cells in commercially available animal-component free, serum-free medium. This work can be used as a basis for efficient production of attenuated as well as wild type Influenza virus for research and vaccine production. PMID:21835017

  16. Accumulation of defective interfering viral particles in only a few passages in Vero cells attenuates mumps virus neurovirulence.

    PubMed

    Šantak, Maja; Markuši?, Maja; Balija, Maja Lang; Kopa?, Sandra Ke?; Jug, Renata; Örvell, Claes; Tomac, Jelena; For?i?, Dubravko

    2015-03-01

    Immunization programs have implemented live attenuated mumps vaccines which reduced mumps incidence ?97%. Some of the vaccine strains were abandoned due to unwanted side effects and the genetic marker of attenuation has not been identified so far. Our hypothesis was that non-infectious viral particles, in particular defective interfering particles (DIPs), contribute to neuroattenuation. We showed that non-infectious particles of the mumps vaccine L-Zagreb attenuated neurovirulence of wild type mumps virus 9218/Zg98. Then, we attenuated recent wild type mumps virus MuVi/Zagreb.HRV/28.12 in Vero cells through 16 passages but already the fifth passage (p5) showed accumulation of DIPs and attenuated neurovirulence in a newborn rat model when compared to the second passage (p2). Sequence analysis of the p2 and p5 revealed a single mutation in the 5' untranslated region of the HN gene. Analysis of the expression level of the HN protein showed that this mutation does not affect the expression of the protein. We conclude that the passages of MuVi/Zagreb.HRV/28.12 in Vero cells for only three passages accumulated DIPs which attenuate neurovirulence. These findings reveal DIPs as a very promising and general neuroattenuating factor which should be considered in the rational design of the new mumps vaccine. PMID:25479555

  17. Chemical Synthesis, Characterisation, and Biocompatibility of Nanometre Scale Porous Anodic Aluminium Oxide Membranes for Use as a Cell Culture Substrate for the Vero Cell Line: A Preliminary Study

    PubMed Central

    Poinern, Gérrard Eddy Jai; Le, Xuan Thi; Becker, Thomas; Fawcett, Derek

    2014-01-01

    In this preliminary study we investigate for the first time the biomedical potential of using porous anodic aluminium oxide (AAO) membranes as a cell substrate for culturing the Cercopithecus aethiops (African green monkey) Kidney (Vero) epithelial cell line. One advantage of using the inorganic AAO membrane is the presence of nanometre scale pore channels that allow the exchange of molecules and nutrients across the membrane. The size of the pore channels can be preselected by adjusting the controlling parameters of a temperature controlled two-step anodization process. The cellular interaction and response of the Vero cell line with an in-house synthesised AAO membrane, a commercially available membrane, and a glass control were assessed by investigating cell adhesion, morphology, and proliferation over a 72?h period. The number of viable cells proliferating over the respective membrane surfaces revealed that the locally produced in-house AAO membrane had cells numbers similar to the glass control. The study revealed evidence of focal adhesion sites over the surface of the nanoporous membranes and the penetration of cellular extensions into the pore structure as well. The outcome of the study has revealed that nanometre scale porous AAO membranes have the potential to become practical cell culture scaffold substrates with the capability to enhance adhesion and proliferation of Vero cells. PMID:24579077

  18. Growth and poliovirus production of Vero cells on a novel microcarrier with artificial cell adhesive protein under serum-free conditions.

    PubMed

    Kurokawa, Masato; Sato, Shigehiro

    2011-05-01

    A microcarrier is used for the three-dimensional (3D) culture of adhesion-dependent mammalian cells. We developed a novel microcarrier by binding ProNectin F, an artificial cell adhesive protein synthesized by genetically engineered Escherichia coli to a polyacrylic superabsorbent polymer. The microcarrier is characterized by containing no animal-derived components. The serum-free culture of Vero cells for vaccine production using the microcarrier increased the number of Vero cells by approximately 30% compared with the existing dextran beads coated with porcine Type I collagen, which resulted in approximately a 30% to 40% increase in the infectivity titer of the Sabin 2 strain of poliovirus. These results suggested that the developed microcarrier should be unprecedented in permitting high-yield vaccine production by means of a serum-free culture. PMID:21262586

  19. Non-Linear Relationships between Aflatoxin B1 Levels and the Biological Response of Monkey Kidney Vero Cells

    PubMed Central

    Rasooly, Reuven; Hernlem, Bradley; He, Xiaohua; Friedman, Mendel

    2013-01-01

    Aflatoxin-producing fungi contaminate food and feed during pre-harvest, storage and processing periods. Once consumed, aflatoxins (AFs) accumulate in tissues, causing illnesses in animals and humans. Most human exposure to AF seems to be a result of consumption of contaminated plant and animal products. The policy of blending and dilution of grain containing higher levels of aflatoxins with uncontaminated grains for use in animal feed implicitly assumes that the deleterious effects of low levels of the toxins are linearly correlated to concentration. This assumption may not be justified, since it involves extrapolation of these nontoxic levels in feed, which are not of further concern. To develop a better understanding of the significance of low dose effects, in the present study, we developed quantitative methods for the detection of biologically active aflatoxin B1 (AFB1) in Vero cells by two independent assays: the green fluorescent protein (GFP) assay, as a measure of protein synthesis by the cells, and the microculture tetrazolium (MTT) assay, as a measure of cell viability. The results demonstrate a non-linear dose-response relationship at the cellular level. AFB1 at low concentrations has an opposite biological effect to higher doses that inhibit protein synthesis. Additional studies showed that heat does not affect the stability of AFB1 in milk and that the Vero cell model can be used to determine the presence of bioactive AFB1 in spiked beef, lamb and turkey meat. The implication of the results for the cumulative effects of low amounts of AFB1 in numerous foods is discussed. PMID:23949006

  20. Differentiation of a Vero cell adapted porcine epidemic diarrhea virus from Korean field strains by restriction fragment length polymorphism analysis of ORF 3

    Microsoft Academic Search

    D. S Song; J. S Yang; J. S Oh; J. H Han; B. K Park

    2003-01-01

    A porcine epidemic diarrhea virus (PEDV) designated DR13 was isolated in Vero cells and serially passaged by level 100. The virus was titrated at regular intervals of the passage level. Open reading frame (ORF) 3 sequences of the virus at passage levels 20, 40, 60, 80, and 100 were aligned and compared using a computer software program. Suitability of the

  1. High-yield production of a stable Vero cell-based vaccine candidate against the highly pathogenic avian influenza virus H5N1

    SciTech Connect

    Zhou, Fangye; Zhou, Jian; Ma, Lei; Song, Shaohui; Zhang, Xinwen; Li, Weidong; Jiang, Shude [No. 5, Department of Bioproducts, Institute of Medical Biology, Chinese Academy of Medical Science and Pecking Union Medical College, Jiaoling Avenue 935, Kunming, Yunnan Province 650102, People's Republic of China (China)] [No. 5, Department of Bioproducts, Institute of Medical Biology, Chinese Academy of Medical Science and Pecking Union Medical College, Jiaoling Avenue 935, Kunming, Yunnan Province 650102, People's Republic of China (China); Wang, Yue, E-mail: euy-tokyo@umin.ac.jp [National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Yingxin Lane 100, Xicheng District, Beijing 100052, People's Republic of China (China)] [National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Yingxin Lane 100, Xicheng District, Beijing 100052, People's Republic of China (China); Liao, Guoyang, E-mail: liaogy@21cn.com [No. 5, Department of Bioproducts, Institute of Medical Biology, Chinese Academy of Medical Science and Pecking Union Medical College, Jiaoling Avenue 935, Kunming, Yunnan Province 650102, People's Republic of China (China)] [No. 5, Department of Bioproducts, Institute of Medical Biology, Chinese Academy of Medical Science and Pecking Union Medical College, Jiaoling Avenue 935, Kunming, Yunnan Province 650102, People's Republic of China (China)

    2012-05-18

    Highlights: Black-Right-Pointing-Pointer Vero cell-based HPAI H5N1 vaccine with stable high yield. Black-Right-Pointing-Pointer Stable high yield derived from the YNVa H3N2 backbone. Black-Right-Pointing-Pointer H5N1/YNVa has a similar safety and immunogenicity to H5N1delta. -- Abstract: Highly pathogenic avian influenza (HPAI) viruses pose a global pandemic threat, for which rapid large-scale vaccine production technology is critical for prevention and control. Because chickens are highly susceptible to HPAI viruses, the supply of chicken embryos for vaccine production might be depleted during a virus outbreak. Therefore, developing HPAI virus vaccines using other technologies is critical. Meeting vaccine demand using the Vero cell-based fermentation process has been hindered by low stability and yield. In this study, a Vero cell-based HPAI H5N1 vaccine candidate (H5N1/YNVa) with stable high yield was achieved by reassortment of the Vero-adapted (Va) high growth A/Yunnan/1/2005(H3N2) (YNVa) virus with the A/Anhui/1/2005(H5N1) attenuated influenza vaccine strain (H5N1delta) using the 6/2 method. The reassorted H5N1/YNVa vaccine maintained a high hemagglutination (HA) titer of 1024. Furthermore, H5N1/YNVa displayed low pathogenicity and uniform immunogenicity compared to that of the parent virus.

  2. MDCK and Vero cells for influenza virus vaccine production: a one-to-one comparison up to lab-scale bioreactor cultivation

    Microsoft Academic Search

    Yvonne Genzel; Christian Dietzsch; Erdmann Rapp; Jana Schwarzer; Udo Reichl

    2010-01-01

    Over the last decade, adherent MDCK (Madin Darby canine kidney) and Vero cells have attracted considerable attention for production\\u000a of cell culture-derived influenza vaccines. While numerous publications deal with the design and the optimization of corresponding\\u000a upstream processes, one-to-one comparisons of these cell lines under comparable cultivation conditions have largely been neglected.\\u000a Therefore, a direct comparison of influenza virus production

  3. Transport of an external Lys-Asp-Glu-Leu (KDEL) protein from the plasma membrane to the endoplasmic reticulum: studies with cholera toxin in Vero cells

    Microsoft Academic Search

    Irina V. Majoul; Philippe I. H. Bastiaens; Hans-Dieter SSling

    1996-01-01

    The A2 chain of cholera toxin (CTX) contains a COOH-terminal Lys-Asp-Glu-Leu (KDEL) se- quence. We have, therefore, analyzed by immunofluo- rescence and by subcellular fractionation in Vero cells whether CTX can be used to demonstrate a retrograde transport of KDEL proteins from the Golgi to the ER. Immunofluorescen ce studies reveal that after a pulse treatment with CTX, the CTX-A

  4. Analysis of protein expression changes of the Vero E6 cells infected with classic PEDV strain CV777 by using quantitative proteomic technique.

    PubMed

    Sun, Dongbo; Shi, Hongyan; Guo, Donghua; Chen, Jianfei; Shi, Da; Zhu, Qinghe; Zhang, Xin; Feng, Li

    2015-06-15

    Recent outbreaks of porcine epidemic diarrhea virus (PEDV) have caused widespread concern. The identification of proteins associated with PEDV infection might provide insight into PEDV pathogenesis and facilitate the development of novel antiviral strategies. We analyzed the differential protein profile of PEDV-infected Vero E6 cells using mass spectrometry and an isobaric tag for relative and absolute quantification. A total of 126 proteins were identified that were differentially expressed between the PEDV-infected and mock-infected groups (P<0.05, quantitative ratio ?1.2), among which the expression of 58 proteins was up-regulated and that of 68 proteins was down-regulated in the PEDV-infected Vero E6 cells, involving in integrin ?2/?3, cystatin-C. The Gene Ontology analysis indicated that the molecular function of the differentially expressed proteins (DEPs) was primarily related to binding and catalytic activity, and that the biological functions in which the DEPs are involved included metabolism, organismal systems, cellular processes, genetic information processing, environmental information processing, and diseases. Among the disease-related functions, certain anti-viral pathways and proteins, such as the RIG-I-like receptor, Rap1, autophagy, mitogen-activated protein kinase, PI3K-Akt and Jak-STAT signaling pathways, and integrin ?2/?3 and cystatin-C proteins, represented potential factors in PEDV infection. Our findings provide valuable insight into PEDV-Vero E6 cell interactions. PMID:25783682

  5. Bicarbonate/chloride antiport in Vero cells: II. Mechanisms for bicarbonate-dependent regulation of intracellular pH

    SciTech Connect

    Olsnes, S.; Ludt, J.; Tonnessen, T.I.; Sandvig, K.

    1987-08-01

    The rates of bicarbonate-dependent uptake and efflux of /sup 22/Na/sup +/ in Vero cells were studied and compared with the uptake and efflux of /sup 36/Cl/sup -/. Both processes were strongly inhibited by DIDS. Whereas the transport of chloride increased approximately ten-fold when the internal pH was increased over a narrow range around neutrality, the uptake of Na/sup +/ was much less affected by changes in pH. The bicarbonate-linked uptake of /sup 22/Na/sup +/ was dependent on internal Cl- but not on internal Na/sup +/. At a constant external concentration of HCO/sub 3/-, the amount of /sup 22/Na/sup +/ associated with the cells increased when the internal concentration of HCO/sub 3/- decreased and vice versa, which is compatible with the possibility that the ion pair NaCO/sub 3/- is the transported species and that the transport is symmetric across the membrane. Bicarbonate inhibited the uptake of /sup 36/Cl/sup -/ both in the absence and presence of Na/sup +/. At alkaline internal pH, HCO/sub 3/- stimulated the efflux of /sup 36/Cl/sup -/ from preloaded cells, while at acidic internal pH both Na/sup +/ and HCO/sub 3/- were required to induce /sup 36/Cl/sup -/ efflux. We propose a model for how bicarbonate-dependent regulation of the internal pH may occur. This model implies the existence of two bicarbonate transport mechanisms that, under physiological conditions, transport OH(-)-equivalents in opposite directions across the plasma membrane.

  6. Apoptosis induced by duck reovirus p10.8 protein in primary duck embryonated fibroblast and Vero E6 cells.

    PubMed

    Geng, Hongwei; Zhang, Yun; Liu-Partanen, Yin; Vanhanseng; Guo, Dongchun; Wang, Yu; Liu, Ming; Tong, Guangzhi

    2009-09-01

    Muscovy duck reovirus (MDRV) is an important poultry pathogen that causes high morbidity and mortality in ducklings. The mechanisms by which viruses kill susceptible cells, and ultimately produce diseases, in Muscovy duck remain poorly understood. In this study, we focused on the biologic functions of the MDRV p10.8 protein in vitro. The p10.8 protein is a small protein of MDRV that is encoded by the first open reading frame of the S4 segment. In our study, the p10.8-encoding gene was individually cloned and expressed in bacterial and eukaryotic cells. The p10.8 protein had no potential transmembrane domain; it shared no sequence similarity to other known fusion-associated small transmembrane proteins encoded by the avian reovirus, Nelson Bay virus or baboon reovirus; and it did not show any syncytium formation activity. The p10.8 protein induced apoptosis when expressed by itself in transfected primary Muscovy duck embryonic fibroblasts or in Vero E6 cells. Four assays were used to analyze the apoptosis induced by p10.8: DNA ladder formation; terminal deoxynucleotidyl transferase dUTP nick end labeling; enzyme-linked immunosorbent assay detection of cytoplasmic histone-associated DNA fragments; and nuclear staining with propidium iodide. Two deletion products, p10.8delta1 (1-63aa; amino acid position) and p10.8delta2 (64-96aa), were constructed. Deletion analysis suggests that p10.8delta1 (1-63aa) is important in mediating p10.8-induced apoptosis because its deletion abolishes induction of apoptosis. PMID:19848085

  7. Reduction of spiked porcine circovirus during the manufacture of a Vero cell-derived vaccine.

    PubMed

    Lackner, Cornelia; Leydold, Sandra M; Modrof, Jens; Farcet, Maria R; Grillberger, Leopold; Schäfer, Birgit; Anderle, Heinz; Kreil, Thomas R

    2014-04-11

    Porcine circovirus-1 (PCV1) was recently identified as a contaminant in live Rotavirus vaccines, which was likely caused by contaminated porcine trypsin. The event triggered the development of new regulatory guidance on the use of porcine trypsin which shall ensure that cell lines and porcine trypsin in use are free from PCV1. In addition, manufacturing processes of biologicals other than live vaccines include virus clearance steps that may prevent and mitigate any potential virus contamination of product. In this work, artificial spiking of down-scaled models for the manufacturing process of an inactivated pandemic influenza virus vaccine were used to investigate inactivation of PCV1 and the physico-chemically related porcine parvovirus (PPV) by formalin and ultraviolet-C (UV-C) treatment as well as removal by the purification step sucrose gradient ultracentrifugation. A PCV1 infectivity assay, using a real-time PCR infectivity readout was established. The formalin treatment (0.05% for 48h) showed substantial inactivation for both PCV1 and PPV with reduction factors of 3.0log10 and 6.8log10, respectively, whereas UV-C treatment resulted in complete PPV (?5.9log10) inactivation already at a dose of 13mJ/cm but merely 1.7log10 at 24mJ/cm(2) for PCV1. The UV-C inactivation results with PPV were confirmed using minute virus of mice (MVM), indicating that parvoviruses are far more sensitive to UV-C than PCV1. The sucrose density gradient ultracentrifugation also contributed to PCV1 clearance with a reduction factor of 2log10. The low pH treatment during the production of procine trypsin was investigated and showed effective inactivation for both PCV1 (4.5log10) and PPV (6.4log10). In conclusion, PCV1 in general appears to be more resistant to virus inactivation than PPV. Still, the inactivated pandemic influenza vaccine manufacturing process provides for robust virus reduction, in addition to the already implemented testing for PCV1 to avoid any contaminations. PMID:24560672

  8. Transcriptional profiling of Vero E6 cells over-expressing SARS-CoV S2 subunit: Insights on viral regulation of apoptosis and proliferation

    SciTech Connect

    Yeung, Y.-S. [Department of Zoology, Kadoorie Biological Science Building, University of Hong Kong, Hong Kong (China)], E-mail: ysyeung@graduate.hku.hk; Yip, C.-W. [Department of Zoology, Kadoorie Biological Science Building, University of Hong Kong, Hong Kong (China)], E-mail: h0024004@hkusua.hku.hk; Hon, C.-C. [Department of Zoology, Kadoorie Biological Science Building, University of Hong Kong, Hong Kong (China)], E-mail: h9826299@hkusua.hku.hk; Chow, Ken Y.C. [Department of Zoology, Kadoorie Biological Science Building, University of Hong Kong, Hong Kong (China)], E-mail: chow@pasteur.fr; Ma, Iris C.M. [Department of Zoology, Kadoorie Biological Science Building, University of Hong Kong, Hong Kong (China)], E-mail: h0105962@hkusua.hku.hk; Zeng Fanya [Department of Zoology, Kadoorie Biological Science Building, University of Hong Kong, Hong Kong (China)], E-mail: fzeng@hkucc.hku.hk; Leung, Frederick C.C. [Department of Zoology, Kadoorie Biological Science Building, University of Hong Kong, Hong Kong (China)], E-mail: fcleung@hkucc.hku.hk

    2008-02-05

    We have previously demonstrated that over-expression of spike protein (S) of severe acute respiratory syndrome coronavirus (SARS-CoV) or its C-terminal subunit (S2) is sufficient to induce apoptosis in vitro. To further investigate the possible roles of S2 in SARS-CoV-induced apoptosis and pathogenesis of SARS, we characterized the host expression profiles induced upon S2 over-expression in Vero E6 cells by oligonucleotide microarray analysis. Possible activation of mitochondrial apoptotic pathway in S2 expressing cells was suggested, as evidenced by the up-regulation of cytochrome c and down-regulation of the Bcl-2 family anti-apoptotic members. Inhibition of Bcl-2-related anti-apoptotic pathway was further supported by the diminution of S2-induced apoptosis in Vero E6 cells over-expressing Bcl-xL. In addition, modulation of CCN E2 and CDKN 1A implied the possible control of cell cycle arrest at G1/S phase. This study is expected to extend our understanding on the pathogenesis of SARS at a molecular level.

  9. Purified Vero cell rabies vaccine and human diploid cell strain vaccine: comparison of neutralizing antibody responses to post-exposure regimens

    PubMed Central

    Suntharasamai, Pravan; Chanthavanich, Pornthep; Warrell, M. J.; Looareesuwan, Sornchai; Karbwang, Juntra; Supanaranond, Wichai; Phillips, R. E.; Jansawan, Weerapol; Xueref, C.; Pouradier-Duteil, X.; Warrell, D. A.

    1986-01-01

    Neutralizing antibody responses to conventional rabies post-exposure regimens of human diploid cell strain vaccine (HDCSV) and the new purified Vero cell rabies vaccine (PVRV) were compared in 58 healthy Thai veterinary students. The geometric mean titres (GMTs) of the group given HDCSV were slightly higher than those given PVRV, but on day 28 the peak GMTs of the two groups were statistically similar. The early antibody response to PVRV was unaffected by the addition of passive immunization, whereas the level of HDCSV response was reduced on day 14, so that there was no difference on that day between the GMTs of the two vaccine groups given HRIG. However, by day 91 the GMT of those given PVRV and HRIG was lower than in those given HDCSV alone or with HRIG. The appearance of antibody was less rapid than was observed in previous studies using multiple-site intradermal vaccination. Side effects were trivial. Our results confirm the promise of this new, potentially more economical tissue culture vaccine, but they suggest that the regimen could be improved. PMID:3734433

  10. Preparation and characterization of an anti-inflammatory agent based on a zinc-layered hydroxide-salicylate nanohybrid and its effect on viability of Vero-3 cells

    PubMed Central

    Ramli, Munirah; Hussein, Mohd Zobir; Yusoff, Khatijah

    2013-01-01

    A new organic-inorganic nanohybrid based on zinc-layered hydroxide intercalated with an anti-inflammatory agent was synthesized through direct reaction of salicylic acid at various concentrations with commercially available zinc oxide. The basal spacing of the pure phase nanohybrid was 15.73 Å, with the salicylate anions arranged in a monolayer form and an angle of 57 degrees between the zinc-layered hydroxide interlayers. Fourier transform infrared study further confirmed intercalation of salicylate into the interlayers of zinc-layered hydroxide. The loading of salicylate in the nanohybrid was estimated to be around 29.66%, and the nanohybrid exhibited the properties of a mesoporous-type material, with greatly enhanced thermal stability of the salicylate compared with its free counterpart. In vitro cytotoxicity assay revealed that free salicylic acid, pure zinc oxide, and the nanohybrid have a mild effect on viability of African green monkey kidney (Vero-3) cells. PMID:23345976

  11. Vero/CHOK1, a novel mixture of cell lines that is optimal for the rescue of influenza A vaccine seeds.

    PubMed

    Medina, Julie; Guillot, Vincent; Totain, Emmanuelle; Rouleau, Marie; Sodoyer, Régis; Moste, Catherine; Legastelois, Isabelle

    2014-02-01

    Seasonal and pandemic influenza vaccine manufacturing is challenged with a tight production schedule. Reverse genetics constitutes a rapid method for creating viruses. Vero and CHOK1 cells were found to be an appropriate cell mixture for the generation of influenza reassortants by reverse genetics under the constraints of vaccine production, such as the use of regulatory-compliant cells and culture media devoid of components of animal origin. In addition, no further amplification in cell or egg substrates was required, thus reducing the time needed to obtain reassortant seed virus. In parallel, the cloning step was shown to be dramatically improved, permitting the rapid vRNA expression of influenza viruses. In addition, nucleoporation of the cells was conducted to more efficiently target the nucleus and avoid the use of chemical reagents containing proteins of animal origin. In conclusion, the reverse genetics system for influenza A viruses reported in this study was shown to be rapid, simple to perform and totally animal component-free to best comply with the requirements of health authorities for the production of a vaccine seed. PMID:24161812

  12. Protective effect of methanol extract from citrus press cakes prepared by far-infrared radiation drying on H2O2-mediated oxidative damage in Vero cells

    PubMed Central

    Wijesinghe, W.A.J.P.; Senevirathne, Mahinda; Oh, Myung-Cheol

    2011-01-01

    In the present study, a suitable drying method was developed for citrus press cakes (CPCs), which are produced as a by-product in citrus juice plants, and the protective effect of methanol extract of CPCs prepared by far-infrared radiation (FIR) drying against H2O2-induced DNA damage was evaluated versus that of freeze-dried CPCs. Methanol extract of FIR-dried CPCs exhibited comparatively good ROS scavenging activity versus the freeze-dried CPCs at the concentration of 100 µg/mL. The extract strongly enhanced the cell viability against H2O2-induced oxidative damage in Vero cells. Lipid peroxidation inhibitory activity of the extract from FIR-dried CPCs was comparable to that of the extract from freeze-dried CPCs. This sample also exhibited good protective effects against H2O2-mediated cell apoptosis as demonstrated by decreased apoptotic body formation in the nuclear staining with Hoechst 33342. In the comet assay, the CPC extracts exhibited strong inhibitory effects against H2O2-mediated DNA damage in a dose-dependent manner. Thus, this study demonstrated that FIR drying effectively preserves CPC as a functionally important natural antioxidant source and the FIR drying can be adapted for drying CPCs and is more economical for massive production than freeze drying. PMID:22125675

  13. 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.

  14. Selection of Escherichia coli heat-labile toxin (LT) inhibitors using both the GM1-ELISA and the cAMP vero cell assay.

    PubMed

    Verhelst, Roderick; Schroyen, Martine; Buys, Nadine; Niewold, Theo

    2013-07-01

    Weaned piglets are very susceptible to diarrhea caused by enterotoxigenic Escherichia coli. In the past, various natural components were proposed to have beneficial effects by reducing the effects of diarrheal infectious diseases in humans and animals, and thus may represent an alternative for the use of (prophylactic) antibiotics. Alternatives may inactivate enterotoxigenic Escherichia coli heat-labile toxin (LT) by interfering with toxin binding to the cellular receptor GM1. In this study, various plants and other natural substances were tested for inhibitory properties, in the GM1 binding assay, and in the LT-induced cAMP production in Vero cells. The toxic dose of each compound was determined in a cell viability assay, and the highest nontoxic concentrations were used in the GM1 and cAMP assays. Results demonstrated that only d-(+)-galactose, lactose, N-acetyl-d-galactosamine, and two tea extracts were able to inhibit the binding of LT to its GM1 receptor. In the cAMP assay, only the two tea extracts showed inhibitory activity. This shows that d-(+)-galactose, lactose, and N-acetyl-d-galactosamine can indeed inhibit LT binding to GM1 based on structural homology with GM1 in the absence of living cells. However, in the cAMP assay, d-(+)-galactose, and lactose, N-acetyl-d-galactosamine are apparently metabolized to below their effective inhibitory concentration, likely predicting limited practical applicability in vivo. Both tea extracts maintained their activity in the presence of cells. The active compounds in both are probably polyphenols, which are not easily metabolized, and most likely work by aggregating the toxin. In conclusion, the combination of methods used here is a convenient and fast method for preselecting natural substances containing potentially toxin-binding compounds. Furthermore, if antidiarrhea activity is attributed to compounds found inactive here, their activity is unlikely based on interference with toxin binding. PMID:23692076

  15. A herpes simplex virus 2 glycoprotein D mutant generated by bacterial artificial chromosome mutagenesis is severely impaired for infecting neuronal cells and infects only Vero cells expressing exogenous HVEM.

    PubMed

    Wang, Kening; Kappel, Justin D; Canders, Caleb; Davila, Wilmer F; Sayre, Dean; Chavez, Mayra; Pesnicak, Lesley; Cohen, Jeffrey I

    2012-12-01

    We constructed a herpes simplex virus 2 (HSV-2) bacterial artificial chromosome (BAC) clone, bHSV2-BAC38, which contains full-length HSV-2 inserted into a BAC vector. Unlike previously reported HSV-2 BAC clones, the virus genome inserted into this BAC clone has no known gene disruptions. Virus derived from the BAC clone had a wild-type phenotype for growth in vitro and for acute infection, latency, and reactivation in mice. HVEM, expressed on epithelial cells and lymphocytes, and nectin-1, expressed on neurons and epithelial cells, are the two principal receptors used by HSV to enter cells. We used the HSV-2 BAC clone to construct an HSV-2 glycoprotein D mutant (HSV2-gD27) with point mutations in amino acids 215, 222, and 223, which are critical for the interaction of gD with nectin-1. HSV2-gD27 infected cells expressing HVEM, including a human epithelial cell line. However, the virus lost the ability to infect cells expressing only nectin-1, including neuronal cell lines, and did not infect ganglia in mice. Surprisingly, we found that HSV2-gD27 could not infect Vero cells unless we transduced the cells with a retrovirus expressing HVEM. High-level expression of HVEM in Vero cells also resulted in increased syncytia and enhanced cell-to-cell spread in cells infected with wild-type HSV-2. The inability of the HSV2-gD27 mutant to infect neuronal cells in vitro or sensory ganglia in mice after intramuscular inoculation suggests that this HSV-2 mutant might be an attractive candidate for a live attenuated HSV-2 vaccine. PMID:22993162

  16. Complete Genome Sequence of a Vero Cell-Adapted Isolate of Porcine Epidemic Diarrhea Virus in Eastern China

    PubMed Central

    Zhao, Mengjiao; Sun, Zhen; Zhang, Yue; Wang, Guisheng; Wang, Hui; Yang, Fangfang

    2012-01-01

    In early 2012, a widespread porcine epidemic diarrhea virus (PEDV) occurred in eastern China. A cell-adapted isolate, SD-M, was at the four-passage level of virulent field strain SD, which was isolated from a 2-day-old dead suckling piglet that had suffered from severe diarrhea in Shandong Province, China. We report here the complete genome sequence of SD-M. This sequence will promote a better understanding of the molecular pathogenesis of PEDV. PMID:23166259

  17. Comparative study on the cytotoxicity of different Myrtaceae essential oils on cultured vero and RC-37 cells.

    PubMed

    Schnitzler, P; Wiesenhofer, K; Reichling, J

    2008-11-01

    Medicinally and commercially important essential oils from the family Myrtaceae, i.e. cajuput, clove, kanuka and manuka were phytochemically analysed by GC-MS. Cytotoxicity of these essential oils was evaluated in a standard neutral red assay. Maximum noncytotoxic concentrations for cajuput oil and clove oil were determined at 0.006%, kanuka oil and manuka oil were more cytotoxic with a maximum noncytotoxic concentration of 0.001%. The compounds alpha-pinene, eugenol and leptospermone demonstrated maximum noncytotoxic concentrations at dilutions of 0.001%, 0.003% and 0.001%, respectively. However, the terpene 1,8-cineole was about 100 times less toxic to cultured cells with a maximum noncytotoxic concentration of 0.1% and a TC50 value of 0.44%. Manuka essential oil exhibited high levels of virucidal activity against HSV-1 as well against drug-resistant HSV-1 isolates in viral suspension tests. Determination of cytotoxicity of natural products is an important prerequisite for application in cosmetic and health care products and in antiviral tests. PMID:19069246

  18. Flake size-dependent cyto and genotoxic evaluation of graphene oxide on in vitro A549, CaCo2 and vero cell lines.

    PubMed

    De Marzi, L; Ottaviano, L; Perrozzi, F; Nardone, M; Santucci, S; De Lapuente, J; Borras, M; Treossi, E; Palermo, V; Poma, A

    2014-01-01

    This study was carried out by varying both graphene oxide (GO) concentration (10 ?g/mL, 50 ?g/mL, 100 ?g/mL) and flakes sizes of 1320 nm and 130 nm. Characterization by scanning electron microscopy and Raman spectroscopy demonstrate that the area of GO flakes varies of one order of magnitude but their chemical structure remains unmodified. A 24-h cytotoxicity test showed, for A549, a loss in the viability, while the test exhibits overall a positive increase in the viability for CaCo2 and Vero. A 24-h comet assay shows a marked GO genotoxicity: for micrometer-sized GO flakes the genotoxicity is in positive correlation with the concentration, while for nanometer-sized GO flakes there was a high degree of genotoxicity at the lowest concentration tested. PMID:25001660

  19. Quantitative Proteomics Using Stable Isotope Labeling with Amino Acids in Cell Culture Reveals Changes in the Cytoplasmic, Nuclear, and Nucleolar Proteomes in Vero Cells Infected with the Coronavirus Infectious Bronchitis Virus*

    PubMed Central

    Emmott, Edward; Rodgers, Mark A.; Macdonald, Andrew; McCrory, Sarah; Ajuh, Paul; Hiscox, Julian A.

    2010-01-01

    Virus-host interactions involve complex interplay between viral and host factors, rendering them an ideal target for proteomic analysis. Here we detail a high throughput quantitative proteomics analysis of Vero cells infected with the coronavirus infectious bronchitis virus (IBV), a positive strand RNA virus that replicates in the cytoplasm. Stable isotope labeling with amino acids in cell culture (SILAC) was used in conjunction with LC-MS/MS to identify and quantify 1830 cellular and two viral proteins from IBV-infected cells. Fractionation of cells into cytoplasmic, nuclear, and nucleolar extracts was used to reduce sample complexity and provide information on the trafficking of proteins between the different compartments. Each fraction showed a proportion of proteins exhibiting ?2-fold changes in abundance. Ingenuity Pathway Analysis revealed that proteins that changed in response to infection could be grouped into different functional categories. These included proteins regulated by NF-?B- and AP-1-dependent pathways and proteins involved in the cytoskeleton and molecular motors. A luciferase-based reporter gene assay was used to validate the up-regulation of AP-1- and NF-?B-dependent transcription in IBV-infected cells and confirmed using immunofluorescence. Immunofluorescence was used to validate changes in the subcellular localization of vimentin and myosin VI in IBV-infected cells. The proteomics analysis also confirmed the presence of the viral nucleocapsid protein as localizing in the cytoplasm, nucleus, and nucleolus and the viral membrane protein in the cytoplasmic fraction. This research is the first application of SILAC to study total host cell proteome changes in response to positive sense RNA virus infection and illustrates the versatility of this technique as applied to infectious disease research. PMID:20467043

  20. Comparison of the antiproliferative activity of crude ethanol extracts of nine salvia species grown in Jordan against breast cancer cell line models

    PubMed Central

    Abu-Dahab, Rana; Afifi, Fatma; Kasabri, Violet; Majdalawi, Lara; Naffa, Randa

    2012-01-01

    Background: The antiproliferative activity of Salvia species grown in Jordan has not been fully evaluated yet. The aim of this work was to study the antiproliferative activity of crude ethanol extracts from nine Salvia species grown in Jordan against a panel of breast cancer cell lines. Material and Methods: Cytotoxic activity was evaluated in human tumor models of breast cancer; MCF-7, T47D, ZR-75-1, and BT 474 by the sulforhodamine B assay. In addition, the extracts were evaluated using a non-transformed cell line (Vero) and normal fibroblast cells in order to demonstrate their selectivity and safety. Results: From the nice ethanol extracts under investigation, those of S. dominica and S. fruticosa showed an inhibitory concentration of 50% of cells (IC50) in concentrations less than 30?g/mL against the four cell lines under investigation. S. syriaca and S. hormium showed an IC50 below 30?g/ml for two out of the four cell lines. S. fruticosa, S. hormium and S. syriaca showed selectivity in their antiproliferative activity against estrogen receptor positive cell lines with minimal toxicity against normal human periodontal fibroblasts. Phytochemical screening using thin layer chromatography indicated the presence of terpenoids, flavonoids and coumarins in all examined extracts. Conclusion: Three of the plant extracts under investigation exhibited antiproliferative activity against breast cancer cells and were shown to be safe and selective. These could be considered as a potential source for novel anticancer therapy. PMID:24082637

  1. OM-VPE grown materials for high efficiency solar cells

    NASA Technical Reports Server (NTRS)

    Saxena, R.; Cooper, B., III; Ludowise, M.; Borden, P.; Gregory, P.

    1980-01-01

    Organometallic sources are available for all the III-V elements and a variety of dopants; thus it is possible to use the technique to grow a wide variety of semiconductor compounds. AlGaAsSb and AlGaInAs alloys for multijunction monolithic solar cells were grown by OM-VPE. While the effort concentrated on terrestrial applications, the success of OM-VPE grown GaAs/AlGaAs concentrator solar cells (23% at 400 suns) demonstrates that OM-VPE is suitable for growing high efficiency solar cells in large quantities for space applications. In addition, OM-VPE offers the potential for substantial cost reduction of photovoltaic devices with scale up and automation and due to high process yield from reproducible, uniform epitaxial growths with excellent surface morphology.

  2. Photosynthetic ability in dark-grown Reboulia hemisphaerica and Barbula unguiculata cells in suspension culture.

    PubMed

    Takio, S; Akita, C; Ngumi, V W; Takami, S

    1990-03-01

    Suspension cultured cells of the liverwort, Reboulia hemisphaerica and of the moss, Barbula unguiculata were independently subcultured in the medium containing 2% glucose in the dark or in the light for more than one year, and the photosynthetic activities of the final cultures were determined. Throughout the culture period light-grown cells of both species contained high amount of chlorophyll (4 to 34 ?g mg(-1) dry weight) and showed a high photosynthetic activity (10 to 84 ?mol O2 mg(-1) chlorophyll h(-1)). Dark-grown cells of R. hemisphaerica showed the same level of chlorophyll content and photosynthetic O2 evolving activity as light-grown cells. Although chlorophyll content in dark-grown B. unguiculata cells was ten-fold lower than that in light-grown cells, the photosynthetic activity of these dark-grown cells was higher than that of light-grown cells based on chlorophyll content. PMID:24232674

  3. Role of Proteus mirabilis MR/P fimbriae and flagella in adhesion, cytotoxicity and genotoxicity induction in T24 and Vero cells.

    PubMed

    Scavone, Paola; Villar, Silvia; Umpiérrez, Ana; Zunino, Pablo

    2015-06-01

    Proteus mirabilis is frequently associated with complicated urinary tract infections (UTI). It is proposed that several virulence factors are associated with P. mirabilis uropathogenicity. The aim of this work was to elucidate genotoxic and cytotoxic effects mediated by MR/P fimbriae and flagella in eukaryotic cells in vitro. Two cell lines (kidney- and bladder-derived) were infected with a clinical wild-type P. mirabilis strain and an MR/P and a flagellar mutant. We evaluated adhesion, genotoxicity and cytotoxicity by microscopy, comet assay and triple staining technique, respectively. Mutant strains displayed lower adhesion rates than the P. mirabilis wild-type strain and were significantly less effective to induce genotoxic and cytotoxic effects compared to the wild type. We report for the first time that P. mirabilis MR/P fimbriae and flagella mediate genotoxic and cytotoxic effects on eukaryotic cells, at least in in vitro conditions. These results could contribute to design new strategies for the control of UTI. PMID:25724892

  4. Cation Metabolism in Relation to Cell Size in Synchronously Grown Tissue Culture Cell

    PubMed Central

    Jung, Chan; Rothstein, Aser

    1967-01-01

    In randomly grown tissue culture cells (mouse leukemic lymphoblast, L5178Y) the number, volume, and Na+ and K+ content increase as an exponential function with a doubling time of 11.3 hr. In synchronously grown cells the volume increase of the population and of single cells follows the same exponential function as in randomly grown cells. In contrast, the cation content fluctuates during a single cell cycle. About 1½ hr after the cell division burst (at the beginning of the S period), a net loss of K+ occurs for a period of about 1 hr amounting to about 20% of the total K. Over the next 5 to 6 hr, the deficit in K+ is eliminated. The Na+ content shows a double fluctuation. It falls during the cell division burst, rises when the K+ content decreases, falls again when K+ content rises, and then increases again before the next cell division burst. The net fluxes of both Na+ and K+ are very small compared to the unidirectional fluxes (less than 5%), thus small changes in the balance of influx and efflux account for the changes in cation content during the growth cycle. Both unidirectional fluxes increase dramatically (by a factor of two) about 2 hr after the cell division burst, and then remain constant until after the next cell division. The pattern of electrolyte regulation during cell division does not follow a simple function such as cell number, cell surface, or cell volume, but must be related to specific internal events in the cell. PMID:6034509

  5. 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.

  6. Polymer electrolyte fuel cell electrodes grown by vapor deposition techniques Pascal Brault*

    E-print Network

    Paris-Sud XI, Université de

    Polymer electrolyte fuel cell electrodes grown by vapor deposition techniques Pascal Brault Abstract: Polymer fuel cell electrode growth using vapor deposition techniques is reviewed. The supports temperature Solid Polymer Fuel Cells, as Proton Exchange Membrane Fuel Cells (PEMFC), Direct alcohol Fuel Cell

  7. Assessment of immunogenic potential of Vero adapted formalin inactivated vaccine derived from novel ECSA genotype of Chikungunya virus

    Microsoft Academic Search

    Mugdha Tiwari; Manmohan Parida; S. R. Santhosh; Mohsin Khan; Paban Kumar Dash; P. V. Lakshmana Rao

    2009-01-01

    The recent resurgence of Chikungunya virus (CHIKV) in India and Indian Ocean Islands with unusual clinical severity is a matter of great public health concern. Despite the fact that CHIKV resurgence is associated with epidemic of unprecedented magnitude, no approved licensed vaccine is currently available. In the present study, a Vero cell adapted purified formalin inactivated prototype vaccine candidate was

  8. MBE grown GaInNAs solar cells for multijunction applications

    Microsoft Academic Search

    David Jackrel; Homan Yuen; Junxian Fu; Seth Bank; Xiaojun Yu; Zhilong Rao; James S. Harris

    2005-01-01

    Triple-junction cells composed of III-V materials currently hold the world record for photovoltaic efficiency. In order to further increase cell efficiency in the future 4- and 5-junction cells incorporating a sub-cell with a bandgap of roughly 1.0 eV will be required. In this study 1.0 eV bandgap GaInNAs devices grown by solid source molecular beam epitaxy are investigated in terms

  9. Aligned Cell Sheets Grown on Thermo-Responsive Substrates with Microcontact Printed Protein Patterns

    E-print Network

    tissue organization on PIPAAm-grafted substrates. Microcontact printing is a straightforwardAligned Cell Sheets Grown on Thermo-Responsive Substrates with Microcontact Printed Protein and inexpensive technique to precisely control cell shape, organization, and function on a variety of surfaces.[19

  10. Photosynthetic ability in dark-grown Reboulia hemisphaerica and Barbula unguiculata cells in suspension culture

    Microsoft Academic Search

    Susumu Takio; Chikako Akita; Victoria Wambui Ngumi; Shinji Takami

    1990-01-01

    Suspension cultured cells of the liverwort, Reboulia hemisphaerica and of the moss, Barbula unguiculata were independently subcultured in the medium containing 2% glucose in the dark or in the light for more than one year, and the photosynthetic activities of the final cultures were determined. Throughout the culture period light-grown cells of both species contained high amount of chlorophyll (4

  11. Single cell protein production by photosynthetic bacteria grown on the clarified effluents of biogas plant

    Microsoft Academic Search

    Sudhanshu Vrati; G. B. Pant

    1984-01-01

    Anaerobically digested cow dung was separated by centrifugation into solid residue and liquid supernatant fractions. Clarified supernatant fraction, rich in volatile fatty acids, supported the growth of photosynthetic bacteria. Single cell protein from different photosynthetic bacteria, grown on clarified supernatant, was found to be rich in essential and sulphur amino acids. Rhodopseudomonas capsulata produced the best single cell protein.

  12. The Accumulation and Degradation Dynamics of Cyanophycin in Cyanobacterial Cells Grown in Symbiotic Associations with Plant Tissues and Cells

    Microsoft Academic Search

    O. A. Gorelova; S. Yu. Kleimenov

    2003-01-01

    Five different artificial associations of cyanobacterial cells with the cells or tissues of nightshade and rauwolfia were studied. The associations grown on nitrogen-containing media produced heterocysts. Cyanobacterial cells in the associations retained their ability to take up combined nitrogen from the medium, to store it in the form of cyanophycin granules, and to use them in the process of symbiotic

  13. Stimulation of hydrogen production in algal cells grown under high CO 2 concentration and low temperature

    Microsoft Academic Search

    Y. Miura; W. Yamada; K. Hirata; K. Miyamoto; M. Kiyohara

    1993-01-01

    When cells ofChlamydomonas sp. MGA 161, a marine green alga, were cultivated at a high CO2 concentration (15% CO2) and low temperature (15°C), the growth lag time was much longer, but the starch accumulated was two times higher than under\\u000a the basal conditions (5% CO2 30°C). When the cells grown in the high-CO2\\/low-temperature conditions were incubated under dark anaerobic conditions,

  14. Analysis of methylglyoxal metabolism in CHO cells grown in culture Sarocha Kingkeohoi and Frank W.R. Chaplen*

    E-print Network

    Tullos, Desiree

    Analysis of methylglyoxal metabolism in CHO cells grown in culture Sarocha Kingkeohoi and Frank W: CHO cell, Inhibitor, Metabolism, Metabolite, Methylglyoxal Abstract Recent evidence suggests. Isolating these factors is necessary in order to maximize culture productivities. Methylglyoxal (MG

  15. Commissioning and initial stereotactic ablative radiotherapy experience with Vero.

    PubMed

    Solberg, Timothy D; Medin, Paul M; Ramirez, Ezequiel; Ding, Chuxiong; Foster, Ryan D; Yordy, John

    2014-01-01

    The purpose of this study is to describe the comprehensive commissioning process and initial clinical performance of the Vero linear accelerator, a new radiotherapy device recently installed at UT Southwestern Medical Center specifically developed for delivery of image-guided stereotactic ablative radiotherapy (SABR). The Vero system utilizes a ring gantry to integrate a beam delivery platform with image guidance systems. The ring is capable of rotating ± 60° about the vertical axis to facilitate noncoplanar beam arrangements ideal for SABR delivery. The beam delivery platform consists of a 6 MV C-band linac with a 60 leaf MLC projecting a maximum field size of 15 × 15 cm² at isocenter. The Vero planning and delivery systems support a range of treatment techniques, including fixed beam conformal, dynamic conformal arcs, fixed gantry IMRT in either SMLC (step-and-shoot) or DMLC (dynamic) delivery, and hybrid arcs, which combines dynamic conformal arcs and fixed beam IMRT delivery. The accelerator and treatment head are mounted on a gimbal mechanism that allows the linac and MLC to pivot in two dimensions for tumor tracking. Two orthogonal kV imaging subsystems built into the ring facilitate both stereoscopic and volumetric (CBCT) image guidance. The system is also equipped with an always-active electronic portal imaging device (EPID). We present our commissioning process and initial clinical experience focusing on SABR applications with the Vero, including: (1) beam data acquisition; (2) dosimetric commissioning of the treatment planning system, including evaluation of a Monte Carlo algorithm in a specially-designed anthropomorphic thorax phantom; (3) validation using the Radiological Physics Center thorax, head and neck (IMRT), and spine credentialing phantoms; (4) end-to-end evaluation of IGRT localization accuracy; (5) ongoing system performance, including isocenter stability; and (6) clinical SABR applications. PMID:24710458

  16. A shift to 50°C provokes death in distinct ways for glucose- and oleate-grown cells of Yarrowia lipolytica

    Microsoft Academic Search

    Thi Minh Ngoc Ta; Lan Cao-Hoang; Cynthia Romero-Guido; Morgane Lourdin; Hanh Phan-Thi; Sébastien Goudot; Pierre-André Marechal; Yves Waché

    Based on the observation that shocks provoked by heat or amphiphilic compounds present some similarities, this work aims at\\u000a studying whether cells grown on oleate (amphiphilic pre-stress) acquire a tolerance to heat shock. In rich media, changing\\u000a glucose for oleate significantly enhanced the cell resistance to the shock, however, cells grown on a minimal oleate medium\\u000a lost their ability to

  17. Sensitivity of Candida Albicans Biofilm Cells Grown on Denture Acrylic to Antifungal Proteins and Chlorhexidine

    PubMed Central

    Pusateri, Christopher R.; Monaco, Edward A.; Edgerton, Mira

    2009-01-01

    Objectives Candida albicans cells form biofilms on polymeric surfaces of dentures and other prostheses introduced into the oral cavity. Many biofilm microorganisms exhibit resistance to antimicrobial agents; C. albicans cells may also develop resistance to naturally-occurring antifungal peptides in human saliva including histatins (Hsts) and defensins (hBDs). Therefore, we evaluated Hst 5 activity on C. albicans biofilm cells compared to planktonic cells and measured whether surface treatment of denture acrylic with Hst 5, hBD-3, or chlorhexidine gluconate could inhibit in vitro biofilm development. Methods Acrylic disks were preconditioned with 500 ?l saliva for 30 min, and inoculated with C. albicans cells (106 cells/ml) for 1 h, at 37 °C. Non-adherent cells were removed by washing and disks and were incubated in YPD growth medium for 24, 48, and 72 h at 37 °C. Candidacidal assays were performed on 48-hour-biofilms and on planktonically-grown cells using Hst 5 (15.5 ?M, 31.25 ?M, 62 ?M). Cell adhesion was compared on disks pre-coated with 0.12% chlorhexidine gluconate, 50 ?M Hst 5, or 0.6 ?M hBD-3 after 24 h, 48 h, and 72 h growth. Results No significant difference was observed in sensitivity to Hst 5 of biofilm cells compared to planktonic cells (p > 0.05). Pre-coating disks with hBD-3 did not inhibit biofilm development; however, Hst 5 significantly inhibited biofilm development at 72 h, while 0.12% chlorhexidine significantly inhibited biofilm development at all time intervals (p < 0.05). Conclusions C. albicans biofilm cells grown on denture acrylic are sensitive to killing by Hst 5. Surface coating acrylic with chlorhexidine or Hst 5 effectively inhibits biofilm growth and has potential therapeutic application. PMID:19249746

  18. Examination of retail chickens and sausages in Britain for vero cytotoxin-producing Escherichia coli.

    PubMed

    Smith, H R; Cheasty, T; Roberts, D; Thomas, A; Rowe, B

    1991-07-01

    Samples from chickens and pork sausages were examined for the presence of Vero cytotoxin-producing Escherichia coli by using DNA probes for the Vero cytotoxin genes. Hybridization was detected in 25% of the 184 sausage samples, but none of the chickens was positive. No E. coli O157:H7 strains were isolated, and serotyping showed that the Vero cytotoxin-producing E. coli strains belonged to eight different O serogroups and that six strains had an unidentifiable O antigen. PMID:1892398

  19. Performance of silicon solar cells fabricated from multiple Czochralski ingots grown by using a single crucible

    NASA Technical Reports Server (NTRS)

    Kachare, A. H.; Uno, F. M.; Miyahira, T.; Lane, R. L.

    1980-01-01

    Results on the performance of solar cells fabricated on wafers from multiple silicon ingots of large diameter, grown by using a single crucible and a sequential melt replenishment Czochralski (CZO) technique are presented. Samples were analyzed for resistivity, dislocation density and impurity content. Solar cells were fabricated from the seed, center and tang end of each ingot to evaluate the growth reproducibility and material quality. The cell efficiency within a given wafer varies by no more than plus or minus 5% of the average value. A small but consistent decrease in the cell efficiency is observed from the first to the fourth ingot grown from a single crucible. This decrease may be related to an increase in impurity content or dislocation density or a combination of both. The efficiency of the cells fabricated from the tang end of the fourth ingot is about 10% lower than that of the control cell. An impurity effects model is employed to correlate this decrease in efficiency with the impurity build-up in the residual melt.

  20. Evaluation of different yeast cell wall mutants and microalgae strains as feed for gnotobiotically grown brine shrimp Artemia franciscana

    Microsoft Academic Search

    Antonio Marques; Jean Dhont; Patrick Sorgeloos; Peter Bossier

    2004-01-01

    The nutritional value of isogenic yeast strains and two microalgal species for gnotobiotically grown Artemia was examined. Yeast cell wall mutants were always better feed for Artemia than their respective wild type. Yeast cells harbouring null mutants for enzymes involved early in the biochemical pathway for cell wall mannoproteins synthesis performed best as feed for Artemia. Yeast cells defective in

  1. 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.

  2. 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.

  3. 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 nudules 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., artifical 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 cells 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 artifical micro or macro-metastases. In each experiment, tumor population 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 population were exposed to either suicide labeling by high specific activity tritated 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.

  4. Influence of chronological aging on the survival and nucleotide content of Saccharomyces cerevisiae cells grown in different conditions: occurrence of a high concentration of UDP-N-acetylglucosamine in stationary cells grown in 2% glucose.

    PubMed

    Osório, Hugo; Silles, Eduardo; Maia, Rita; Peleteiro, Bárbara; Moradas-Ferreira, Pedro; Günther Sillero, María A; Sillero, Antonio

    2005-02-01

    Saccharomyces cerevisiae cells (strain W303) grown in a minimal medium (containing 2% or 0.1% glucose) until exponential or stationary phase, were subjected to chronological aging in water, and yeast viability and nucleotide content were analyzed along several days of nutrient starvation. Cells collected in exponential phase (whether grown in the presence of 0.1% or 2% glucose) were viable up to five days and thereafter the viability decreased linearly with a half-survival rate of around eight days. ATP and other nucleoside triphosphates decreased similarly in both cases. Cells collected in stationary phase, and transferred to water, behaved differently whether grown in 0.1% or in 2% glucose, with a half-survival life of around nine and 28 days respectively. A double mutant in glycogen synthase (gsy1delta gsy2delta) and its isogenic wild-type strain, grown to stationary phase in 2% glucose, presented a similar half-survival life of around eight days. The W303 cells grown to stationary phase in the presence of 2% glucose showed a 7-fold increase of UDP-N-acetylglucosamine (UDP-GlcNAc) as compared with the level present in the cells grown in any of the other three metabolic situations. The nature of UDP-GlcNAc was established by MALDI-TOF ionization analysis. It is also worth noting that the rate of decay of NAD+ was lower than that of ATP in any of the situations here considered. PMID:15691744

  5. Ferrous iron production mediated by tetrathionate hydrolase in tetrathionate-, sulfur-, and iron-grown Acidithiobacillus ferrooxidans ATCC 23270 cells.

    PubMed

    Sugio, Tsuyoshi; Taha, Taher M; Takeuchi, Fumiaki

    2009-06-01

    When tetrathionate-grown Acidithiobacillus ferrooxidans ATCC 23270 cells were incubated with ferric ions and tetrathionate at pH 3.0, ferrous ions were produced enzymatically. Fe(3+)-reductase, which catalyzes Fe(3+) reduction with tetrathionate, was purified to homogeneity not only from tetrathionate-grown, but also from sulfur- and iron-grown A. ferrooxidans ATCC 23270 cells. The results for apparent molecular weight measured by SDS-PAGE (52.3 kD) and the N-terminal amino acid sequences of the purified enzymes from iron-, sulfur, and tetrathionate-grown cells (AVAVPMDSTG) indicate that Fe(3+)-reductase corresponds to tetrathionate hydrolase. The evidence that tetrathionate-grown A. ferrooxidans ATCC 23270 cells have high iron-oxidizing activity at the early log phase, comparable to that of iron-grown ATCC 23270 cells, is supported by our finding that tetrathionate hydrolase produces Fe(2+) from tetrathionate during growth on tetrathionate. This is the first report on ferric reductase activity associated with tetrathionate hydrolase. PMID:19502725

  6. 33 CFR 110.73b - Indian River at Vero Beach, Fla.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Indian River at Vero Beach, Fla. 110.73b Section 110.73b Navigation and Navigable...Special Anchorage Areas § 110.73b Indian River at Vero Beach, Fla. (a) Area A. Beginning at a point located on the...

  7. 33 CFR 110.73b - Indian River at Vero Beach, Fla.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Indian River at Vero Beach, Fla. 110.73b Section 110.73b Navigation and Navigable...Special Anchorage Areas § 110.73b Indian River at Vero Beach, Fla. (a) Area A. Beginning at a point located on the...

  8. 33 CFR 110.73b - Indian River at Vero Beach, Fla.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Indian River at Vero Beach, Fla. 110.73b Section 110.73b Navigation and Navigable...Special Anchorage Areas § 110.73b Indian River at Vero Beach, Fla. (a) Area A. Beginning at a point located on the...

  9. 33 CFR 110.73b - Indian River at Vero Beach, Fla.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Indian River at Vero Beach, Fla. 110.73b Section 110.73b Navigation and Navigable...Special Anchorage Areas § 110.73b Indian River at Vero Beach, Fla. (a) Area A. Beginning at a point located on the...

  10. 33 CFR 110.73b - Indian River at Vero Beach, Fla.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Indian River at Vero Beach, Fla. 110.73b Section 110.73b Navigation and Navigable...Special Anchorage Areas § 110.73b Indian River at Vero Beach, Fla. (a) Area A. Beginning at a point located on the...

  11. SYNTHESIS OF CELLULOSE FROM PYRUVATE BY SUCCINATE-GROWN CELLS OF ACETOBACTER XYLINUM

    PubMed Central

    Benziman, Moshe; Burger-Rachamimov, H.

    1962-01-01

    Benziman, Moshe (The Hebrew University of Jerusalem, Jerusalem, Israel) and H. Burger-Rachamimov. Synthesis of cellulose from pyruvate by succinate-grown cells of Acetobacter xylinum. J. Bacteriol. 84:625–630. 1962.—Pyruvate was converted into cellulose by succinate-grown cells of Acetobacter xylinum. With pyruvate-1-, 2-, or 3-C14 as substrate, the upper half of the cellulose monomer mirrored the lower half, both as to total content and distribution of C14. In each case, about 75% of the total radioactivity of the cellulose monomer was found in two carbon atoms (carbon pairs 3:4, 2:5, and 1:6, derived from pyruvate-1-, 2-, and 3-C14, respectively). The carbonyl carbon of pyruvate contributed 2 equivalents to the cellulose monomer, compared with 1.4 and 2.8 equivalents contributed by the pyruvate carboxyl and methyl carbons, respectively. Cellulose formed in the presence of pyruvate and C14O2 was nonradioactive. The results suggest that the carbon chain of the cellulose monomer is formed in these cells via a condensation involving two molecules of a three-carbon compound. Reactions involving pyruvate which could account for the observed distribution of C14 in cellulose are discussed. PMID:13967586

  12. Genetic transformation and cell morphology of Bacillus subtilis grown in Mg+(+)-limited chemostat culture.

    PubMed

    Sevinc, M S; Bainbridge, B W; Bazin, M J

    1990-01-01

    The rate and frequency of genetic transformation of Bacillus subtilis grown in Mg+(+)-limited chemostat culture are dependent on the dilution rate (D) of the system and achieved maximum values at D = 0.23 h-1. Mg+(+)-limitation induced a morphological change in the cells from their normal rod shape to extended helices. Although this change in shape was a transient phenomenon, under some conditions it persisted for several days and resulted in an apparent increase in the transformation frequency. PMID:2110611

  13. Proliferation and differentiation potential of human adipose-derived stem cells grown on chitosan hydrogel.

    PubMed

    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

  14. 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

  15. 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. PMID:21942189

  16. Phase III Clinical Trials Comparing the Immunogenicity and Safety of the Vero Cell-Derived Japanese Encephalitis Vaccine Encevac with Those of Mouse Brain-Derived Vaccine by Using the Beijing-1 Strain

    PubMed Central

    Miyazaki, Chiaki; Okada, Kenji; Ozaki, Takao; Hirose, Mizuo; Iribe, Kaneshige; Ishikawa, Yuji; Togashi, Takehiro; Ueda, Kohji

    2014-01-01

    The immunogenicity and safety of an inactivated cell culture Japanese encephalitis vaccine (CC-JEV) were compared with those of an inactivated mouse brain-derived Japanese encephalitis vaccine (MB-JEV) in phase III clinical multicenter trials conducted in children. The vaccines contain the same Japanese encephalitis virus strain, the Beijing-1 strain. Two independent clinical trials (trials 1 and 2) were conducted. Trial 1 was conducted in 468 healthy children. Each subject was injected with 17 ?g per dose of either CC-JEV or MB-JEV, and the immunogenicity and safety of the vaccines were investigated. Trial 1 showed that CC-JEV was more immunogenic and reactive than MB-JEV at the same dose. Therefore, to adjust the immunogenicity of CC-JEV to that of MB-JEV, a vaccine that has had a good track record regarding its efficacy for a long time, trial 2 was conducted in 484 healthy children. To improve the stability, CC-JEV was converted from a liquid type to a freeze-dried type of vaccine. Each subject was injected subcutaneously with either 4 ?g per dose of CC-JEV, 8 ?g per dose of CC-JEV, or 17 ?g per dose of MB-JEV twice, at an interval of 2 to 4 weeks, followed by an additional booster immunization 1 to 15 months after the primary immunization. Based on the results of trial 2, 4 ?g per dose of the freeze-dried CC-JEV (under the label Encevac) was selected as a substitute for the MB-JEV. Encevac was approved and launched in 2011 and has since been in use as a 2nd-generation Japanese encephalitis vaccine in Japan. (These studies have been registered at the JapicCTI under registration no. JapicCTI-132063 and JapicCTI-080586 for trials 1 and 2, respectively.) PMID:24334689

  17. 77 FR 42425 - Amendment of Air Traffic Service (ATS) Routes in the Vicinity of Vero Beach, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-19

    ...ATS) Routes in the Vicinity of Vero Beach, FL AGENCY: Federal Aviation Administration...and V-537, in the vicinity of Vero Beach, FL. The FAA is taking this action because the name of the Vero Beach, FL, VOR Tactical Air Navigation...

  18. 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.

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

    PubMed

    Nedukha, O; Brown, C S; Kordyum, E; Piastuch, W C

    1999-07-01

    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. PMID:11542987

  20. 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.

  1. Differential Response in Downstream Processing of CHO Cells Grown Under Mild Hypothermic Conditions

    PubMed Central

    Tait, Andrew S; Tarrant, Richard D R; Velez-Suberbie, M Lourdes; Spencer, Daniel I R; Bracewell, Daniel G

    2013-01-01

    The manufacture of complex therapeutic proteins using mammalian cells is well established, with several strategies developed to improve productivity. The application of sustained mild hypothermic conditions during culture has been associated with increases in product titer and improved product quality. However, despite associated cell physiological effects, very few studies have investigated the impact on downstream processing (DSP). Characterization of cells grown under mild hypothermic conditions demonstrated that the stationary phase was prolonged by delaying the onset of apoptosis. This enabled cells to maintain viability for extended periods and increase volumetric productivity from 0.74 to 1.02 g L?1. However, host cell proteins, measured by ELISA, increased by ?50%, attributed to the extended time course and higher peak and harvest cell densities. The individual components making up this impurity, as determined by SELDI-TOF MS and 2D-PAGE, were shown to be largely comparable. Under mild hypothermic conditions, cells were less shear sensitive than those maintained at 37°C, enhancing the preliminary primary recovery step. Adaptive changes in membrane fluidity were further investigated by adopting a pronounced temperature shift immediately prior to primary recovery and the improvement observed suggests that such a strategy may be implementable when shear sensitivity is of concern. Early and late apoptotic cells were particularly susceptible to shear, at either temperature, even under the lowest shear rate investigated. These findings demonstrate the importance of considering the impact of cell culture strategies and cell physiology on DSP, by implementing a range of experimental methods for process characterization. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:688–696, 2013 PMID:23636936

  2. 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

  3. Investigation of Indium Gallium Nitride Grown via Metal Organic Chemical Vapor Deposition in Various Crystallographic Orientations for Solar Cell Applications

    NASA Astrophysics Data System (ADS)

    Cruz, Samantha Christine

    Solar cell technology has long relied upon Si and GaAs based materials. While this industry is mature, it has approached a plateau in the push to increase efficiency. It has been proposed that the InGaN ternary materials system is ideal for this purpose. In this work we report on the growth, fabrication and testing of photovoltaic properties of InGaN based solar cells grown via metalorganic chemical vapor deposition (MOCVD). In order for solar cells to work effectively, a minimum active region thickness is necessary for sufficient absorption of photons for conversion. At low In content compositions, high quality material has been grown and a simple p-i-n type solar cell with a single absorbing layer can be produced. However, at high In content compositions critical thickness limits for the thin films are well below the thickness requirements for full absorption. High In compositions are necessary to efficiently match the solar spectrum when designing multijunction solar cells. Solar cells require a thickness of 100-200 nm for sufficient absorption. Growth optimization and results for p-i-n type: single double heterostructures, multiple double heterostructure (MDH), and MQW, solar cells will be reported for InGaN grown on sapphire in the +c [0001] orientation as well as InGaN grown on bulk m-plane (10-10) substrates. Non-polar oriented growth of InGaN was investigated since as In content increases in typical c-plane growth, the polarization fields in the double heterostructure design of the p-i-n solar cell oppose the built in field of the junction and could potentially hinder carrier collection. At low In content, m-plane InGaN solar cells outperform c-plane solar cells with the same composition due to the higher quality material grown homoepitaxially on bulk GaN substrates.

  4. Apical and basolateral endocytosis in Madin-Darby canine kidney (MDCK) cells grown on nitrocellulose filters.

    PubMed Central

    von Bonsdorff, C H; Fuller, S D; Simons, K

    1985-01-01

    Madin-Darby canine kidney (MDCK) cells (strain I) grown on 0.45 micron pore size nitrocellulose filters formed monolayers which were highly polarized and had high transepithelial electrical resistance (greater than 3000 ohm X cm2). Morphometric analysis showed that the area of the basolateral surface domain was 7.6 times larger than that of the apical. The uptake of fluid-phase markers [3H]inulin and horseradish peroxidase (HRP) was studied from the apical and the basal side of the monolayer. Uptake of [3H]inulin was biphasic and the rate during the first 40 min corresponded to a fluid phase uptake of 20.5 X 10(-8) nl/min per cell from the basolateral side, and 1.0 X 10(-8) nl/min per cell from the apical side. Electron micrographs of the monolayers after HRP uptake showed that the marker was rapidly delivered into endosome-like vesicles and into multivesicular bodies. No labelling of the Golgi complex could be observed during 2 h of uptake. Evidence was obtained for the transport of fluid phase markers across the cell. HRP and fluorescein isothiocyanate-dextran crossed the monolayers in either direction at a rate corresponding to approximately 3 X 10(-8) nl of fluid/min/cell. Adding the transcytosis rate to the rate of fluid accumulation into the cell yielded a total basolateral endocytic rate which was 6-fold greater than the apical rate. When the uptake rates were normalized for membrane area the apical and basolateral endocytic rates were about equal per unit cell surface area. Images Fig. 1. Fig. 2. Fig. 4. Fig. 5. Fig. 6. Fig. 7. Fig. 8. Fig. 1. PMID:4065093

  5. Inhibition by salbutamol of the proliferation of human airway smooth muscle cells grown in culture.

    PubMed Central

    Tomlinson, P. R.; Wilson, J. W.; Stewart, A. G.

    1994-01-01

    1 beta 2-Adrenoceptor agonists may exacerbate asthma by reducing the release of the anti-proliferative and anti-inflammatory molecule, heparin from mast cells in the airway. In this study, the direct effects of the clinically used bronchodilator, salbutamol, on the proliferation of airway smooth muscle cells grown in culture and stimulated with a range of mitogens have been examined. 2 In mitogen-stimulated cells, salbutamol (0.1-100 nM) inhibited [3H]-thymidine incorporation in a concentration-dependent manner. Salbutamol (100 nM) pretreatment reduced the mitogenic responses to thrombin (0.3 u ml-1), epidermal growth factor (EGF) (300 pM) and U46619 (100 nM) by 61.7 +/- 6.1%, 46.9 +/- 13.9% and 57.6 +/- 12.7%, respectively. However, salbutamol pretreatment did not appear to reduce the small mitogenic response to endothelin-1. 3 Increases in [3H]-leucine incorporation in thrombin (0.3 u ml-1)-stimulated cells were reduced by salbutamol (100 nM) by 27.7 +/- 2.8%. Similarly, thrombin (0.3 u ml-1)-stimulated increases in cell number were also inhibited by salbutamol (100 nM) pretreatment. Thus, the effect of salbutamol in decreasing thrombin-induced [3H]-leucine incorporation may, at least in part, be explained by inhibition of cell proliferation. 4 The inhibition of cell proliferation by salbutamol was prevented by pretreatment with either the non-selective beta-adrenoceptor antagonist, propranolol (0.3 microM) or the selective beta 2-adrenoceptor antagonist, ICI 118551 (50 nM). 5 These results indicate that salbutamol, through activation of a beta 2-adrenoceptor, has a direct inhibitory effect on proliferation elicited by the mitogens thrombin, EGF, and U46619.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7911722

  6. Improved lentiviral gene transfer into human embryonic stem cells grown in co-culture with murine feeder and stroma cells.

    PubMed

    Wurm, Melanie; Gross, Benjamin; Sgodda, Malte; Ständker, Ludger; Müller, Thomas; Forssmann, Wolf-Georg; Horn, Peter A; Blasczyk, Rainer; Cantz, Tobias

    2011-10-01

    Genetic modification of human embryonic stem cells (hESCs) using biophysical DNA transfection methods are hampered by the very low single cell survival rate and cloning efficiency of hESCs. Lentiviral gene transfer strategies are widely used to genetically modify hESCs but limited transduction efficiencies in the presence of feeder or stroma cells present problems, particularly if vesicular stomatitis virus glycoprotein (VSV-G) pseudotyped viral particles are applied. Here, we investigated whether the recently described semen derived enhancer of virus infection (SEVI) and alternative viral envelope proteins derived from either Gibbon ape leukaemia virus (GALV) or feline leukaemia virus (RD114) are applicable for transducing hESCs during co-culture with feeder or stroma cells. Our first set of experiments demonstrates that SEVI has no toxic effect on murine or hESCs and that exposure to SEVI does not interfere with the pluripotency-associated phenotype. Focusing on hESCs, we were able to further demonstrate that SEVI increases the transduction efficiencies of GALV and RD114 pseudotyped lentiviral vectors. More importantly, aiming at targeted differentiation of hESCs into functional somatic cell types, GALV pseudotyped lentiviral particles could efficiently and exclusively transduce hESCs grown in co-culture with OP9-GFP stroma cells (which were often used to induce differentiation into haematopoietic derivatives). PMID:21812756

  7. Membrane-DNA attachment sites in Streptococcus faecalis cells grown at different rates.

    PubMed Central

    Parks, L C; Rigney, D; Daneo-Moore, L; Higgins, M L

    1982-01-01

    The M-band technique was used to assess the number of attachment points of DNA to the cell membrane of Streptococcus faecalis grown at three different rates. Cells were X irradiated in liquid nitrogen and then analyzed simultaneously for the introduction of double-strand breaks into the chromosome and the degree of removal of DNA from the cell membrane (M band). Consideration of the data from these experiments and of the topology of the bacterial chromosome resulted in a reevaluation of former quantitative models. Our results are consistent with a semiquantitative model in which the bacterial chromosome is organized around a core structure. We interpret our data to mean that the core is attached to the membrane and that the complexity of the core changes more drastically with growth rate than does the number of membrane-DNA attachment points. An alternative model in which RNA hybridizes with DNA containing single- and double-strand breaks is also discussed. In any event, the complexity of these interactions precludes a reliable estimate of the number of membrane-DNA attachment sites. PMID:6811550

  8. Carriers transport properties in GaInP solar cells grown by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Dai, P.; Lu, S. L.; Arimochi, M.; Uchida, S.; Watanabe, T.; Luo, X. D.; Yang, H.

    2014-12-01

    The transport properties of carriers in GaInP solar cells grown by molecular beam epitaxy are investigated by temperature-dependent current-voltage (I-V) measurements. In contrast to GaInP/AlGaInP heterostructure, a long PL decay time is observed in GaInP/AlInP, which is ascribed to a lower interface recombination due to an improved carriers' confinement in the case of the high-energy barrier. However, the series resistance induced by the high potential barrier at GaInP/AlInP interface due to a big valence band offset prevents the improvement of solar cell's performance. An S-shape like I-V characteristic observed at low temperatures indicates that the transport of major carriers is limited by the barrier. A calculation based on the combination of a normal photovoltaic device with a barrier-affected thermal carriers transport explicitly explains this abnormal I-V characteristic. Our study demonstrates the critical role of the barrier-induced series resistance in the determination of solar cell's performance.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    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/cm2. 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.

  10. Flexible dye-sensitized solar cells with ZnO nanoparticles grown by Sonochemistry over Graphene/PET substrates.

    E-print Network

    Pala, Nezih

    Flexible dye-sensitized solar cells with ZnO nanoparticles grown by Sonochemistry over Graphene/PET (PET)) has been widely used as substrate for flexible electrodes. However ITO is expensive report on fabrication of ZnO nanostructure over Graphene/PET substrates to be used as photoelectrodes

  11. GaAs tunnel junction grown by metalorganic vapor-phase epitaxy for multigap cascade solar cells

    NASA Astrophysics Data System (ADS)

    Basmaji, P.; Guittard, M.; Rudra, A.; Carlin, J. F.; Gibart, P.

    1987-09-01

    GaAs tunnel p-n junctions with peak current densities up to 45 A cm-2 were grown by metallorganic vapor-phase epitaxy. These tunnel diodes are suitable for intercell ohmic contacts between the case of integrated tandem photovoltaic subcells in solar cells based on GaAs. The peak current is high enough for concentration up to C=1000.

  12. A549 lung epithelial cells grown as three-dimensional aggregates: alternative tissue culture model for Pseudomonas aeruginosa pathogenesis.

    PubMed

    Carterson, A J; Höner zu Bentrup, K; Ott, C M; Clarke, M S; Pierson, D L; Vanderburg, C R; Buchanan, K L; Nickerson, C A; Schurr, M J

    2005-02-01

    A three-dimensional (3-D) lung aggregate model was developed from A549 human lung epithelial cells by using a rotating-wall vessel bioreactor to study the interactions between Pseudomonas aeruginosa and lung epithelial cells. The suitability of the 3-D aggregates as an infection model was examined by immunohistochemistry, adherence and invasion assays, scanning electron microscopy, and cytokine and mucoglycoprotein production. Immunohistochemical characterization of the 3-D A549 aggregates showed increased expression of epithelial cell-specific markers and decreased expression of cancer-specific markers compared to their monolayer counterparts. Immunohistochemistry of junctional markers on A549 3-D cells revealed that these cells formed tight junctions and polarity, in contrast to the cells grown as monolayers. Additionally, the 3-D aggregates stained positively for the production of mucoglycoprotein while the monolayers showed no indication of staining. Moreover, mucin-specific antibodies to MUC1 and MUC5A bound with greater affinity to 3-D aggregates than to the monolayers. P. aeruginosa attached to and penetrated A549 monolayers significantly more than the same cells grown as 3-D aggregates. Scanning electron microscopy of A549 cells grown as monolayers and 3-D aggregates infected with P. aeruginosa showed that monolayers detached from the surface of the culture plate postinfection, in contrast to the 3-D aggregates, which remained attached to the microcarrier beads. In response to infection, proinflammatory cytokine levels were elevated for the 3-D A549 aggregates compared to monolayer controls. These findings suggest that A549 lung cells grown as 3-D aggregates may represent a more physiologically relevant model to examine the interactions between P. aeruginosa and the lung epithelium during infection. PMID:15664956

  13. 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. PMID:22539188

  14. Antioxidant activity of Haematococcus pluvialis cells grown in continuous culture as a function of their carotenoid and fatty acid content

    Microsoft Academic Search

    M. C. Cerón; M. C. García-Malea; J. Rivas; F. G. Acien; J. M. Fernandez; E. Del Río; M. G. Guerrero; E. Molina

    2007-01-01

    The influence of culture conditions on the quality of Haematococcus pluvialis biomass is assessed. Continuously grown cells have been characterised with respect to their astaxanthin, fatty acid content,\\u000a and antioxidant activity and compared with those of non-growing haematocysts. Moderate limitation of nitrate availability\\u000a (1.7 mM) under continuous growth conditions favoured the production of reddish palmelloid cells whose extracts possessed antioxidant\\u000a activity

  15. Stimulation of hydrogen production in algal cells grown under high CO[sub 2] concentration and low temperature

    Microsoft Academic Search

    Y. Miura; W. Yamada; K. Hirata; K. Miyamoto; M. Kiyohara

    2009-01-01

    When cells of Chlamydomonas sp. MGA 161, a marine green alga, were cultivated at a high CO[sub 2] concentration (15% CO[sub 2]) and low temperature (15[degrees]C), the growth lag time was much longer, but the starch accumulated was two times higher than under the basal conditions (5% CO[sub 2] 30[degrees]C). When the cells grown in the high-CO[sub 2]\\/low-temperature conditions were

  16. Targeting FAK Radiosensitizes 3-Dimensional Grown Human HNSCC Cells Through Reduced Akt1 and MEK1/2 Signaling

    SciTech Connect

    Hehlgans, Stephanie [OncoRay-National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden (Germany) [OncoRay-National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden (Germany); Department of Radiotherapy and Oncology, University of Frankfurt, Frankfurt am Main (Germany); Institute of Radiopharmacy, Helmholtz Center Dresden-Rossendorf, Dresden (Germany); Eke, Iris [OncoRay-National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden (Germany)] [OncoRay-National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden (Germany); Cordes, Nils, E-mail: Nils.Cordes@OncoRay.de [OncoRay-National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden (Germany) [OncoRay-National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden (Germany); Institute of Radiopharmacy, Helmholtz Center Dresden-Rossendorf, Dresden (Germany); Department of Radiation Oncology, University Hospital and Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden (Germany)

    2012-08-01

    Purpose: Focal adhesion kinase (FAK), a main regulator of integrin signaling and cell migration, is frequently overexpressed and hyperphosphorylated in human head-and-neck squamous cell carcinoma (HNSCC). We have previously shown that pharmacologic FAK inhibition leads to radiosensitization of 3-dimensionally grown HNSCC cell lines. To further evaluate the role of FAK in radioresistance and as a potential cancer target, we examined FAK and FAK downstream signaling in HNSCC cell lines grown in more physiologic extracellular matrix-based 3-dimensional cell cultures. Methods and Materials: Seven HNSCC cell lines were grown in 3-dimensional extracellular matrix and the clonogenic radiation survival, expression, and phosphorylation of FAK, paxillin, Akt1, extracellular signal-regulated kinase (ERK)1/2, and MEK1/2 were analyzed after siRNA-mediated knockdown of FAK, Akt1, MEK1, FAK+Akt1, or FAK+MEK1 compared with controls or stable overexpression of FAK. The role of MEK1/2 for clonogenic survival and signaling was investigated using the MEK inhibitor U0126 with or without irradiation. Results: FAK knockdown moderately or significantly enhanced the cellular radiosensitivity of 3-dimensionally grown HNSCC cells. The FAK downstream targets paxillin, Akt1, and ERK1/2 were substantially dephosphorylated under FAK depletion. FAK overexpression, in contrast, increased radiation survival and paxillin, Akt1, and ERK1/2 phosphorylation. The degree of radiosensitization upon Akt1, ERK1/2, or MEK1 depletion or U0126 was superimposable to FAK knockdown. Combination knockdown conditions (ie, Akt1/FAK, MEK1/FAK, or U0126/FAK) failed to provide additional radiosensitization. Conclusions: Our data provide further evidence for FAK as important determinant of radiation survival, which acts in the same signaling axis as Akt1 and ERK1/2. These data strongly support our hypothesis that FAK is a relevant molecular target for HNSCC radiotherapy.

  17. Proteomic analysis of Staphylococcus aureus biofilm cells grown under physiologically relevant fluid shear stress conditions

    PubMed Central

    2014-01-01

    Background The biofilm forming bacterium Staphylococcus aureus is responsible for maladies ranging from severe skin infection to major diseases such as bacteremia, endocarditis and osteomyelitis. A flow displacement system was used to grow S. aureus biofilms in four physiologically relevant fluid shear rates (50, 100, 500 and 1000 s-1) to identify proteins that are associated with biofilm. Results Global protein expressions from the membrane and cytosolic fractions of S. aureus biofilm cells grown under the above shear rate conditions are reported. Sixteen proteins in the membrane-enriched fraction and eight proteins in the cytosolic fraction showed significantly altered expression (p?

  18. 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, E-mail: Albrecht@anaesthesie.uni-kiel.de

    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 not influence any of the investigated parameters under hypoxia.

  19. GaAs tunnel junction grown by metalorganic vapor-phase epitaxy for multigap cascade solar cells

    SciTech Connect

    Basmaji, P.; Guittard, M.; Rudra, A.; Carlin, J.F.; Gibart, P.

    1987-09-01

    GaAs tunnel p-n junctions with peak current densities up to 45 A cm/sup -2/ were grown by metallorganic vapor-phase epitaxy. These tunnel diodes are suitable for intercell ohmic contacts between the case of integrated tandem photovoltaic subcells in solar cells based on GaAs. The peak current is high enough for concentration up to C = 1000.

  20. 1 Rectangular Bunched Rutile TiO2 Nanorod Arrays Grown on Carbon 2 Fiber for Dye-Sensitized Solar Cells

    E-print Network

    Wang, Zhong L.

    1 Rectangular Bunched Rutile TiO2 Nanorod Arrays Grown on Carbon 2 Fiber for Dye-Sensitized Solar desirable for this 44 technology. 45 Here we introduce a fiber-shaped solar cell based on carbon 46 fibers a study of rectangular bunched 13 TiO2 nanorod (NR) arrays grown on carbon fibers (CFs) 14 from titanium

  1. 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. PMID:7872771

  2. High targeted migration of human mesenchymal stem cells grown in hypoxia is associated with enhanced activation of RhoA

    PubMed Central

    2013-01-01

    Introduction A feature which makes stem cells promising candidates for cell therapy is their ability to migrate effectively into damaged or diseased tissues. Recent reports demonstrated the increased motility of human mesenchymal stem cells (hMSC) grown under hypoxic conditions compared to normoxic cells. However, the directional migration of hMSC cultured in hypoxia has not been investigated. In this study we examined the in vitro transmembrane migration of hMSC permanently cultured in hypoxia in response to various cytokines. We also studied the involvement of RhoA, a molecule believed to play an essential role in the migration of MSC via reorganization of the cytoskeleton. Methods We compared the directional migration of human hMSCs grown permanently under normal (21%, normoxic) and low O2 (5%, hypoxic) conditions until passage 4 using an in vitro transmembrane migration assay. A series of 17 cytokines was used to induce chemotaxis. We also compared the level of GTP-bound RhoA in the cell extracts of calpeptin-activated hypoxic and normoxic hMSC. Results We found that hMSC cultured in hypoxia demonstrate markedly higher targeted migration activity compared to normoxic cells, particularly towards wound healing cytokines, including those found in ischemic and myocardial infarction. We also demonstrated for the first time that hMSC are dramatically more sensitive to activation of RhoA. Conclusions The results of this study indicate that high directional migration of hMSCs permanently grown in hypoxia is associated with the enhanced activation of RhoA. The enhanced migratory capacity of hypoxic hMSC would further suggest their potential advantages for clinical applications. PMID:23295150

  3. VIPARnd - GeVero® tool in planning of TPS scheduled brain tumour radiotherapy

    NASA Astrophysics Data System (ADS)

    Kozicki, Marek; Maras, Piotr; Rybka, Krzysztof; Biega?ski, Tadeusz

    2009-05-01

    In this paper, VIPARnd - GeVero® tool is presented for the first time in an application to a brain tumour radiotherapy. Whereas usefulness of VIPARnd polymer gel in various radiotherapy techniques has recently been confirmed, GeVero® software for calculation of MRI polymer gel data and comparison with TPS dose distribution simulation is now examined. The results demonstrate satisfactory agreement between polymer gel dosimetry-MRI and TPS dose distributions and prove helpfulness of the software and VIPARnd polymer gel in radiotherapy dosimetry. It is also believed that the software facilitates data processing and therefore should be of further support in po-gel dosimetry studies.

  4. 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.

  5. 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 ?m/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.

  6. Study of a 1?eV GaNAsSb photovoltaic cell grown on a silicon substrate

    SciTech Connect

    Tan, K. H.; Loke, W. K.; Wicaksono, S.; Li, D.; Leong, Y. R.; Yoon, S. F. [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore)] [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); Sharma, P.; Milakovich, T.; Bulsara, M. T.; Fitzgerald, E. A. [Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139 (United States)] [Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139 (United States)

    2014-03-10

    We report the performance of a 1?eV GaNAsSb photovoltaic cell grown on a Si substrate with a SiGe graded buffer grown using molecular beam epitaxy. For comparison, the performance of a similar 1?eV GaN{sub 0.018}As{sub 0.897}Sb{sub 0.085} photovoltaic cell grown on a GaAs substrate was also reported. Both devices were in situ annealed at 700?°C for 5?min, and a significant performance improvement over our previous result was observed. The device on the GaAs substrate showed a low open circuit voltage (V{sub OC}) of 0.42?V and a short circuit current density (J{sub SC}) of 23.4?mA/cm{sup 2} while the device on the Si substrate showed a V{sub OC} of 0.39?V and a J{sub SC} of 21.3?mA/cm{sup 2}. Both devices delivered a quantum efficiency of 50%–55% without any anti-reflection coating.

  7. [The accumulation and degradation dynamics of cyanophycin in cyanobacteria grown in symbiotic associations with plant tissues and cells].

    PubMed

    Gorelova, O A; Kle?menov, S Iu

    2003-01-01

    Five different artificial associations of cyanobacterial cells with the cells or tissues of nightshade and rauwolfia were studied. The associations grown on nitrogen-containing media produced heterocysts. Cyanobacterial cells in the associations retained their ability to take up bound nitrogen from the medium, to store it in the form of cyanophycin granules, and to use them in the process of symbiotic growth. The synthesis and degradation of cyanophycin granules in cyanobacterial cells were more active in the associations than in monocultures. In the symbiotic associations of Chlorogloeopsis fritschii ATCC 27193 with Solanum laciniatum cells and of Nostoc muscorum CALU 304 with the Rauwolfia serpentina callus, heterocysts were produced at 3- to 30-fold higher cyanophycin contents than in cyanobacterial monocultures. In contrast, in the association of N. muscorum CALU 304 with the Solanum dulcamara callus, heterocysts were produced at lower cyanophycin contents than in the N. muscorum CALU 304 monoculture. The degradation of cyanophycin granules in N. muscorum CALU 304 cells grown in associations with plant tissues or cells was subjected to mathematical analysis. The activation of cyanophycin degradation and heterocyst production in the associations N. muscorum CALU 304-R. serpentina and C. fritschii-S. laciniatum was accompanied by an enhanced synthesis of the nitrogen-containing alkaloids in plant cells. The data obtained suggest that an integrated system of nitrogen homeostasis can be formed in symbiotic associations. Depending on the growth stage of an association, its plant member can either stimulate the accumulation of bound nitrogen in vegetative cyanobacterial cells in the form of cyanophycin granules, or activate their degradation, or initiate the formation of heterocysts independently of the cyanobacterial sensory-signalling system. PMID:12901011

  8. 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.

  9. 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.

  10. 75 FR 65581 - Proposed Amendment and Revocation of Class E Airspace, Vero Beach, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-26

    ...designated as an extension to Class D surface area at Vero Beach Municipal Airport...Class E airspace designated as surface area to remove any reference to the...designated as an extension to Class D surface area to eliminate controlled...

  11. 75 FR 79293 - Amendment and Revocation of Class E Airspace; Vero Beach, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-20

    ...designated as an extension to Class D surface area at Vero Beach Municipal Airport...Class E airspace designated as surface areas, Class E airspace areas designated as an extension to a Class D surface area, and Class E airspace areas...

  12. Biotransformation of d-Limonene to (+) trans-Carveol by Toluene-Grown Rhodococcus opacus PWD4 Cells

    PubMed Central

    Duetz, Wouter A.; Fjällman, Ann H. M.; Ren, Shuyu; Jourdat, Catherine; Witholt, Bernard

    2001-01-01

    The toluene-degrading strain Rhodococcus opacus PWD4 was found to hydroxylate d-limonene exclusively in the 6-position, yielding enantiomerically pure (+) trans-carveol and traces of (+) carvone. This biotransformation was studied using cells cultivated in chemostat culture with toluene as a carbon and energy source. The maximal specific activity of (+) trans-carveol formation was 14.7 U (g of cells [dry weight])?1, and the final yield was 94 to 97%. Toluene was found to be a strong competitive inhibitor of the d-limonene conversion. Glucose-grown cells did not form any trans-carveol from d-limonene. These results suggest that one of the enzymes involved in toluene degradation is responsible for this allylic monohydroxylation. Another toluene degrader (Rhodococcus globerulus PWD8) had a lower specific activity but was found to oxidize most of the formed trans-carveol to (+) carvone, allowing for the biocatalytic production of this flavor compound. PMID:11375201

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

    PubMed Central

    2011-01-01

    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. PMID:22040124

  14. 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.

  15. Adipose-derived stromal cells grown on a hydroxyapatite scaffold can support hematopoiesis in regenerated bone marrow in vivo.

    PubMed

    Ueda, Takahiro; Fujita, Atsushi; Ogawa, Rei; Itoh, Yasuhiko; Fukunaga, Yoshitaka; Shimada, Takashi; Migita, Makoto

    2014-06-01

    Osteoblastic cells are a key component of the bone marrow (BM) stem cell niche and help regulate hematopoietic stem cells (HSCs). We have previously demonstrated that adipose-derived stromal cells (ADSCs) can differentiate into both osteogenic and chondrogenic cells in vitro. The current study examined whether the anatomical architecture of the BM could be regenerated in vivo by using ADSCs cultured on a hydroxyapatite (HA) scaffold. ADSCs from GFP transgenic mice were cultured in vitro on an HA scaffold. The scaffold with the attached cells was implanted subcutaneously onto the backs of C57/BL6 (Ly5.2) recipient mice. Lineage-negative (Lin-) Ly5.1 BM cells transduced with a lentiviral vector containing the luciferase (Luc) gene were intravenously administered to the recipient mice after lethal irradiation. Eight weeks after BM transplantation, the scaffolds were removed from the first recipient mice and subcutaneously implanted into lethally irradiated second recipient mice. The biodistribution and kinetics of Luc(+) Ly5.1 cells were monitored by bioluminescence imaging and flow cytometry. Luc(+) hematopoietic cells were present in the scaffolds of the secondary implanted mice for at least 8 months. Subcutaneous injection of G-CSF resulted in wide distribution of bioluminescence signals from the original scaffolds to the whole body. Therefore, BM regenerated using ADSCs grown on an HA scaffold can support HSC populations in vivo, suggesting that a functional BM niche is reconstituted. These results may have a significant impact on the development of therapeutic strategies for various hematopoietic diseases. PMID:24474575

  16. High efficiency monolithic GaAs/Si tandem solar cells grown by MOCVD

    SciTech Connect

    Yang, Mingju; Soga, Tetsuo; Jimbo, Takashi; Umeno, Masayoshi [Nagoya Inst. of Tech. (Japan)

    1994-12-31

    A monolithic high-efficiency GaAs/Si cascade solar cell fabricated by MOCVD is demonstrated. It consists of the GaAs top cell and the Si bottom cell. Using a buffer layer of Al{sub 0.3}Ga{sub 0.7}As, the conversion efficiency of the GaAs top cell is described from 15.1% from 14.2%, but it makes the efficiency of the Si bottom cell increased from 4.3% to 5.3%. The theoretical analyses of the Si bottom cell are carried out. The suitable resistivity of p-Si substrate for the Si bottom cell is founded to be 10 {Omega}{center_dot}cm, which corresponded with the experimental results. The total conversion efficiency of the GaAs/Si tandem solar cell is 19.5% (1 sun, AM0) which has been achieved in a three-terminal configuration.

  17. 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.

  18. 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.

  19. Enzymatic Detachment of Therapeutic Mesenchymal Stromal Cells Grown on Glass Carriers in a Bioreactor

    PubMed Central

    Salzig, Denise; Schmiermund, Alexandra; P. Grace, Pablo; Elseberg, Christiane; Weber, Christian; Czermak, Peter

    2013-01-01

    Cell therapies require the in vitro expansion of adherent cells such as mesenchymal stromal cells (hMSCs) in bioreactor systems or other culture environments, followed by cell harvest. As hMSCs are strictly adherent cells, cell harvest requires cell detachment. The use of hMSCs for cell therapy requires GMP production in accordance with the guidelines for advanced therapeutic medical products. Therefore, several GMP-conform available proteolytic enzymes were investigated for their ability to promote hMSC detachment. An allogeneic hMSC cell line (hMSC-TERT) that is used in clinical trials in the form of alginate cell capsules was chosen as a model. This study investigated the influence of several factors on the outcome of proteolytic hMSC-TERT detachment. Therefore, hMSC-TERT detachment was analyzed in different cultivation systems (static, dynamic) and in combination with further cell processing including encapsulation. Only two of the commercially available enzymes (AccutaseTM, TrypZeanTM) that fulfill all process requirements (commercial availability, cost, GMP conditions during manufacturing and non-animal origin) are found to be generally suitable for detaching hMSC-TERT. Combining cell detachment with encapsulation demonstrated a high impact of the experimental set up on cell damage. It was preferable to reduce the temperature during detachment and limit the detachment time to a maximum of 20 minutes. Cell detachment in static systems was not comparable with detachment in dynamic systems. Detachment yields in dynamic systems were lower and cell damage was higher for the same experimental conditions. Finally, only TrypZeanTM seemed to be suitable for the detachment of hMSC-TERT from dynamic reactor systems. PMID:24478807

  20. Comparison of Chlamydia trachomatis serovar L2 growth in polarized genital epithelial cells grown in three-dimensional culture with non-polarized cells.

    PubMed

    Dessus-Babus, Sophie; Moore, Cheryl G; Whittimore, Judy D; Wyrick, Priscilla B

    2008-04-01

    A common model for studying Chlamydia trachomatis and growing chlamydial stocks uses Lymphogranuloma venereum serovar L2 and non-polarized HeLa cells. However, recent publications indicate that the growth rate and progeny yields can vary considerably for a particular strain depending on the cell line/type used, and seem to be partially related to cell tropism. In the present study, the growth of invasive serovar L2 was compared in endometrial HEC-1B and endocervical HeLa cells polarized on collagen-coated microcarrier beads, as well as in HeLa cells grown in tissue culture flasks. Microscopy analysis revealed no difference in chlamydial attachment/entry patterns or in inclusion development throughout the developmental cycle between cell lines. Very comparable growth curves in both cell lines were also found using real-time PCR analysis, with increases in chlamydial DNA content of 400-500-fold between 2 and 36 h post-inoculation. Similar progeny yields with comparable infectivity were recovered from HEC-1B and HeLa cell bead cultures, and no difference in chlamydial growth was found in polarized vs. non-polarized HeLa cells. In conclusion, unlike other C. trachomatis strains such as urogenital serovar E, invasive serovar L2 grows equally well in physiologically different endometrial and endocervical environments, regardless of the host cell polarization state. PMID:18396437

  1. 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. (Netherlands Cancer Institute, Amsterdam (Netherlands))

    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.

  2. The surveillance of vero cytotoxin-producing Escherichia coli O157 in Wales, 1990 to 1998.

    PubMed Central

    Chalmers, R. M.; Parry, S. M.; Salmon, R. L.; Smith, R. M.; Willshaw, G. A.; Cheasty, T.

    1999-01-01

    Population-based surveillance for Vero cytotoxin-producing Escherichia coli (VTEC) O157 has been carried out in Wales since 1990. The annual incidence has remained stable during the 9-year period (mean: 1.6 cases per 100,000 population); the rate is highest in children younger than 5 years of age. Blood in the stool is reported in fewer than half the cases, indicating the importance of screening all fecal specimens for VTEC O157. PMID:10458968

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

    PubMed

    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

  4. Role of Shiga/Vero toxins in pathogenesis

    PubMed Central

    Obata, Fumiko; Obrig, Tom

    2014-01-01

    Shiga toxin (Stx) is the primary cause of severe host responses including renal and central nervous system (CNS) disease in Shiga toxin-producing E. coli (STEC) infections. The interaction of Stx with different eukaryotic cell types is described. Host responses to Stx and bacterial lipopolysaccharide (LPS) are compared as related to the features of the STEC-associated Hemolytic Uremic Syndrome (HUS). Data derived from animal models of HUS and CNS disease, in vivo, and eukaryotic cells, in vitro, are evaluated in relation to HUS disease of humans. PMID:25530918

  5. Hall Effect Studies of AlGaAs Grown by Liquid-Phase Epitaxy for Tandem Solar Cell Applications

    NASA Astrophysics Data System (ADS)

    Zhao, Xin; Montgomery, Kyle H.; Woodall, Jerry M.

    2014-11-01

    We report results from Hall effect studies on Al x Ga1- x As ( x = 0.23-0.24) with bandgap energies of 1.76 ± 0.01 eV grown by liquid-phase epitaxy (LPE). Room-temperature Hall measurements on unintentionally doped AlGaAs revealed p-type background doping for concentrations in the range 3.7-5.2 × 1016 cm-3. Sn, Te, Ge, and Zn-doped AlGaAs were also characterized to study the relationship between doping concentrations and the atomic fractions of the dopants in the melt. Temperature-dependent Hall measurements were performed to determine the activation energies of the four dopants. Deep donor levels (DX centers) were dominant for Sn-doped Al0.24Ga0.76As, but not for Te-doped Al0.24Ga0.76As. Comparison of the temperature-dependent Hall effect results for unintentionally and intentionally doped Al0.24Ga0.76As indicated that the impurity contributing to the p-type background doping had the same activation energy as Mg. We thus suggest a Te-doped emitter and an undoped or Ge-doped base to maximize the efficiency of Al x Ga1- x As ( x ˜ 0.23) solar cells grown by LPE.

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

    SciTech Connect

    Zhou, D.; Sharma, G.; Fimland, B. O. [Department of Electronics and Telecommunications, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Vullum, P. E.; Thomassen, S. F.; Holmestad, R.; Reenaas, T. W. [Department of Physics, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway)

    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.

  7. 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 TNF? 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.

  8. An Easy-To-Handle Microfluidic Device Suitable for Immunohistochemical Procedures in Mammalian Cells Grown Under Flow Conditions

    PubMed Central

    Fede, C.; Fortunati, I.; Petrelli, L.; Guidolin, D.; De Caro, R.; Ferrante, C.; Albertin, G.

    2014-01-01

    Microfluidics, the technology that manipulates small amount of fluids in microscale complex devices, has undergone a remarkable development during the last decade, by targeting a significant range of applications, including biological tests and single-cell analysis, and by displaying many advantages such as reduced reagent consumption, decreased costs and faster analysis. Furthermore, the introduction of microfluidic tools has revolutionized the study of vascular functions, because the controlled three-dimensional environment and the continuous perfusion provided by the microdevice allow simulating the physiological characteristics of the circulatory system. Researchers interested in the study of vascular physiology, however, are often hampered by the difficulty in handling reduced number of cells after growth in these devices. This work shows how to apply different protocols commonly used in biology, such as the immunofluorescence technique, to cells grown in reversibly-bound microfluidic devices, obtaining results comparable to those retrieved under static conditions in multiwells. In this way, we are able to combine the advantages of microfluidic, i.e., application of continuous flow and shear stress, with classical protocols for the study of endothelial cells. PMID:24998924

  9. 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.

  10. MDR-1-overexpression in HT 29 colon cancer cells grown in SCID mice.

    PubMed

    Schumacher, Udo; Nehmann, Nina; Adam, Elizabeth; Mukthar, Dhia; Slotki, Itzchak N; Horny, Hans-Peter; Flens, Marcel J; Schlegelberger, Brigitte; Steinemann, Doris

    2012-10-01

    The multidrug-resistance 1 (MDR-1) P-glycoprotein (Pgp) is a transmembrane transporter system, which actively pumps cytotoxic drugs out of the cell. MDR-1 acquired in vitro differs from MDR-1 acquired in vivo, but has important consequences on the cellular phenotype and metastatic behavior. Here we report that the human colonic cancer cell line HT29 (MDR-1 negative) is more malignant than its MDR-1 overexpressing variant (HT29 MDR-1 positive). HT29 MDR-1 negative cells produce undifferentiated signet ring carcinomas when implanted subcutaneously into SCID mice, while HT29 MDR-1 positive cells form tumors with tubular structures, but without signet ring cells. Immunohistochemical proliferation marker analysis revealed that the MDR-1 positive cells proliferate much more slowly than the MDR-1 negative cells. MDR-1 overexpression results in a less differentiated phenotype at the cellular level (absence of mucin producing cells) but in a more differentiated phenotype at the tissue level (tubule formation). In addition, lectin binding patterns including that of Helix pomatia agglutinin (HPA), an indicator of metastatic potential, differed between the two cell lines. HT29 MDR-1 positive cells had less HPA binding sites than HT29 MDR-1 negative counterparts and metastasized less frequently in SCID mice. As slow proliferation, low degree of differentiation and multidrug-resistance is a hallmark of cancer stem cells and all were present in MDR-1 positive tumors, it is attractive to speculate that they represent a stem cell rich tumor. As shown by global gene expression analyses, genes involved, e.g. in cell adhesion, glycosylation and signal transduction, were deregulated in MDR-1 positive tumors compared to MDR-negative tumors. Overexpression of E-cadherin and carcinoembryonic antigen-related cell adhesion molecules 1 (CEACAM1) may provide clues to the mechanisms responsible for the reduced metastatic potential of MDR-1 overexpressing tumors. Since drug treatment shifted the cells towards a less metastatic phenotype in this in vivo model, it seems conceivable to achieve this using drug treatment also in a clinical situation. PMID:22154301

  11. 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.

  12. Lattice-matched ZnTe and CdZnTe\\/ZnTe heterostructures grown on GaSb for multijunction solar cell applications

    Microsoft Academic Search

    S. Wang; X. Liu; D. Ding; S.-N. Wu; S. R. Johnson; S.-Q. Yu; J. K. Furdyna; Y.-H. Zhang

    2008-01-01

    Monolithically integrated high-efficiency multijunction solar cells are highly desirable for both space and terrestrial applications. This paper reports recent experimental work on newly proposed multijunction solar cell designs that utilize lattice-matched II\\/VI CdZnSeTe and III\\/V AlGaAsSb materials grown on GaSb substrates. Single ZnTe layers and thin CdZnTe\\/ZnTe quantum wells have been grown on GaSb substrates using molecular beam epitaxy. Reflection

  13. Identification of morphological differences between avian influenza A viruses grown in chicken and duck cells.

    PubMed

    Al-Mubarak, Firas; Daly, Janet; Christie, Denise; Fountain, Donna; Dunham, Stephen P

    2015-03-01

    Although wild ducks are considered to be the major reservoirs for most influenza A virus subtypes, they are typically resistant to the effects of the infection. In contrast, certain influenza viruses may be highly pathogenic in other avian hosts such as chickens and turkeys, causing severe illness and death. Following in vitro infection of chicken and duck embryo fibroblasts (CEF and DEF) with low pathogenic avian influenza (LPAI) viruses, duck cells die more rapidly and produce fewer infectious virions than chicken cells. In the current study, the morphology of viruses produced from CEF and DEF cells infected with low pathogenic avian H2N3 was examined. Transmission electron microscopy showed that viruses budding from duck cells were elongated, while chicken cells produced mostly spherical virions; similar differences were observed in viral supernatants. Sequencing of the influenza genome of chicken- and duck-derived H2N3 LPAI revealed no differences, implicating host cell determinants as responsible for differences in virus morphology. Both DEF and CEF cells produced filamentous virions of equine H3N8 (where virus morphology is determined by the matrix gene). DEF cells produced filamentous or short filament virions of equine H3N8 and avian H2N3, respectively, even after actin disruption with cytochalasin D. These findings suggest that cellular factors other than actin are responsible for the formation of filamentous virions in DEF cells. The formation of elongated virions in duck cells may account for the reduced number of infectious virions produced and could have implications for virus transmission or maintenance in the reservoir host. PMID:25613009

  14. Rectangular bunched rutile TiO2 nanorod arrays grown on carbon fiber for dye-sensitized solar cells.

    PubMed

    Guo, Wenxi; Xu, Chen; Wang, Xue; Wang, Sihong; Pan, Caofeng; Lin, Changjian; Wang, Zhong Lin

    2012-03-01

    Because of their special application in photovoltaics, the growth of one-dimensional single-crystalline TiO(2) nanostructures on a flexible substrate is receiving intensive attention. Here we present a study of rectangular bunched TiO(2) nanorod (NR) arrays grown on carbon fibers (CFs) from titanium by a "dissolve and grow" method. After a corrosion process in a strong acid solution, every single nanorod is etched into a number of small nanowires. Tube-shaped dye-sensitized solar cells are fabricated by using etched TiO(2) NRs-coated CFs as the photoanode. An absolute energy conversion efficiency of 1.28% has been demonstrated under 100 mW cm(-2) AM 1.5 illumination. This work demonstrates an innovative method for growing bunched TiO(2) NRs on flexible substrates that can be applied in flexible devices for energy harvesting and storage. PMID:22300521

  15. Effect of cell density and irradiance on growth, proximate composition and eicosapentaenoic acid production of Phaeodactylum tricornutum grown in a tubular photobioreactor

    Microsoft Academic Search

    Tjandra Chrismadha; Michael A. Borowitzka

    1994-01-01

    Growth and eicosapentaenoic acid (EPA) productivity of the diatomPhaeodactylum tricornutum grown semicontinuously in a helical tubular photobioreactor were examined under a range of irradiances (approximately 56 to 1712 µmol photons m-2 s-1) and cell densities (?3 × 106 to 18 × 106 cells mL-1). Self shading sets the upper limit of operational maximum cell density. Higher irradiance increases this upper

  16. Effects of thiourea concentration on CdS thin films grown by chemical bath deposition for CdTe solar cells

    Microsoft Academic Search

    R. Mendozaperez; G. Santanarodriguez; J. Sastrehernandez; A. Moralesacevedo; A. Ariascarbajal; O. Vigilgalan; J. C. Alonso; G. Contreraspuente

    2005-01-01

    We study the effects of thiourea concentration on CdS thin films deposited by chemical bath deposition (CBD), submitted to post-thermal treatments of CdCl2, and its effect on the characteristics of CdS\\/CdTe solar cells. We compare these cells with similar ones fabricated with CdS-films grown by Close Space Vapor Transport (CSVT). The CBD-CdS cells shows higher open circuit voltage (Voc) and

  17. The action of 5-fluorouracil on human HT29 colon cancer cells grown in SCID mice: mitosis, apoptosis and cell differentiation.

    PubMed Central

    Sharma, R.; Adam, E.; Schumacher, U.

    1997-01-01

    This study investigates the effects of the anti-metabolite 5-fluorouracil (5-FU) on the human colon cancer line HT29 (10(7) cells per dose) grown subcutaneously in severe combined immunodeficient (SCID) mice. The efficacy of 5-FU was quantitatively evaluated by comparing the tumour weight, mitotic and apoptotic tumour cell indices and the expression of the Ki-67 nuclear antigen in drug-treated animals and control animals. The tumour cell carbohydrates were assessed using a lectin panel. A significant reduction in the tumour weight was found 4 days after initial 5-FU treatment. 5-FU treatment reduced the percentages of mitoses but increased the apoptotic index in the tumour cells. In addition, 5-FU induced an increase in the signet ring cell population and an increased binding for lectins specific for N-acetylgalactosamine and galactose. However, the vast majority of signet ring cells were negative for Ki-67. The results of this study indicate that continuous treatment with 5-FU for 4 days targets metabolic processes relevant for both cell division and apoptosis. The relative increase in the signet ring population can be explained by the fact that the more proliferation-active stem cell population of the tumour is the primary target of the therapy. The lectin-binding patterns reflect these changes and are therefore differentiation linked. Images Figure 2 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 PMID:9376259

  18. A market analysis for high efficiency multi-junction solar cells grown on SiGe

    E-print Network

    Judkins, Zachara Steele

    2007-01-01

    Applications, markets and a cost model are presented for III-V multi-junction solar cells built on compositionally graded SiGe buffer layers currently being developed by professors Steven Ringell of Ohio State University ...

  19. Cryopreservation of Dendritic Cells Grown in Vitro from Monocytes for Their Future Clinical Use.

    PubMed

    Cao, Hua; Verg, Véronique; Martinache, Chantal; Leon, Anne; Gorin, Norbert-Claude; Bernard, Jacky; Lopez, Manuel

    2000-12-01

    Dendritic cells are professional antigen presenting cells which are being used as adjuvants in tumor vaccination trials. Most clinical protocols currently include 4 to 10 weekly infusions of doses > 10(6) cells, each inoculum coming from a simple culture of blood monocytes. In the present study, several millions of dendritic cells from a single leukapheresis were produced; monocytes were isolated by elutriation and then cultured in Teflon bags in presence of 800 U/ml GM-CSF + 100 micro g/ml IL-13 + 10% fetal calf serum (FCS). The dendritic cells from this single batch were aliquoted in many doses for potential multiple infusions and cryopreserved in 10% DMSO + 2% human albumin in Teflon-kapton Fresenius bags either at -1 degrees C/min using a controlled rate freezer, or putting the bags directly in a -80 degrees C mechanical freezer without controlling the temperature rate. Six experiments were carried out. After one month of cryopreservation, the cells were thawed in a 40 degrees C water bath. Before and after freezing, cells were evaluated for immunophenotype (CD1a, CD14, CD40, CD80, CD83, CD86, CD54, CD58, CD16, CD32, CD64 and HLA-DR) and for their capacity to stimulate allogenic (MLR) or autologous (antigen presentation tests) lymphocytes. The results demonstrated that the mean recovery rates after freezing in liquid nitrogen or at -80 degrees C were (67 +/- 14)% and (71 +/- 13)% respectively, without any significant difference between the two techniques. The immunophenotype was not modified by the freezing-thawing procedure, as well as the lymphocyte stimulating capacities. In conclusion, our study showed that substantial numbers of functional DCs can be derived from peripheral blood monocytes using Teflon bags. DCs can be cryopreserved in a good laboratory practice setting for further clinical trials with an acceptable loss of cells and without modification of their functions. PMID:12578659

  20. Water relations of individual leaf cells of Mesembryanthemum crystallinum plants grown at low and high salinity

    Microsoft Academic Search

    Joachim Rygol; Ulrich Zimmermann; Angelika Balling

    1989-01-01

    Summary The effects of saline conditions on the water relations of cells in intact leaf tissue of the facultative CAM plantMesembryanthemum crystallinum were studied using the pressure probe technique. During a 12-hr light\\/dark regime a maximum in turgor pressure was recorded for the mesophyll cells of salttreated (CAM) plants at the beginning of the light period followed 6 hr later

  1. 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

    2008-12-01

    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. PMID:19019373

  2. 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. [Department of Electronics and Telecommunications, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Thomassen, S. F.; Reenaas, T. W. [Department of Physics, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway)

    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.

  3. Branched respiratory chain in aerobically grown Staphylococcus aureus —oxidation of ethanol by cells and protoplasts

    Microsoft Academic Search

    Vladislav Yu. Artzatbanov; Valery V. Petrov

    1990-01-01

    Addition of ethanol and some other primary alcohols, except methanol, to cells and protoplasts (but not membrane particles) considerably stimulated the rate of oxygen consumption. This additional respiration was strongly inhibited by 0.1 mM KCN. The cyanide inhibition curve of endogenous substrate oxidation was slightly biphasic while in the presence of ethanol it became clearly biphasic having Ki values of

  4. Survival and development of ciliary ganglion neurones grown alone in cell culture

    Microsoft Academic Search

    Rae Nishi; Darwin K. Berg

    1979-01-01

    NEURONAL cell death is a conspicuous part of development for many neuronal populations in the vertebrate nervous system1,2. Although little is known about the mechanisms that control neurone death, it seems that interactions with the postsynaptic target tissue are important. Thus, for the chick ciliary ganglion (CG), Landmesser and Pilar showed that half of the neurones present die between days

  5. Clonal vaccinia virus grown in cell culture as a new smallpox vaccine

    Microsoft Academic Search

    Jian Liu; Konstantin V Pugachev; Gwendolyn A Myers; Brie Coughlin; Paul S Blum; Richard Nichols; Casey Johnson; John Cruz; Jeffrey S Kennedy; Francis A Ennis; Richard Weltzin; Thomas P Monath

    2003-01-01

    Although the smallpox virus was eradicated over 20 years ago, its potential release through bioterrorism has generated renewed interest in vaccination. To develop a modern smallpox vaccine, we have adapted vaccinia virus that was derived from the existing Dryvax vaccine for growth in a human diploid cell line. We characterized six cloned and one uncloned vaccine candidates. One clone, designated

  6. 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. PMID:23210995

  7. 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 otherwise die or be rendered reproductively inactive in 2-D culture.

  8. Inverted polymer solar cells based on thin ZnO films grown by Mist chemical vapor deposition system

    NASA Astrophysics Data System (ADS)

    Biswas, Chandan; Ma, Zhu; Zhu, Xiaodan; Kawaharamura, Toshiyuki; Wang, Kang L.

    2014-10-01

    Extensive investigations have been conducted in order to synthesize high quality Zinc oxide (ZnO) thin films for numerous applications. These methods are either expensive to make or result polycrystalline thin films with low optoelectronic properties. Here we demonstrated a simple and inexpensive method to grow high quality ZnO thin films by a mist chemical vapor assisted depositing (Mist-CVD) system for inverted polymer solar cell (IPSC) application. The IPSC performance fabricated by Mist-CVD grown ZnO thin films were compared with two different Zn precursors (Zinc acetylacetonate hydrate and Zinc acetate dehydrate). Variations in IPSC performance on the growth temperature and growth time of the ZnO thin films were prominently demonstrated. The surface morphology of the ZnO films was investigated using scanning electron microscopy, atomic force microscopy and correlated with IPSC performance. The IPSC performance using two different precursors has been compared thoroughly. A 24% increase in solar cell efficiency (contributed from 21% increase in fill factor and 151% increase in shunt resistance) was achieved using Zinc acetate dehydrate compare to Zinc acetylacetonate hydrate precursor. The transmittance of ZnO thin films was evaluated by transmission spectroscopy. High performance IPSC can be fabricated using this simple and inexpensive method by synthesizing high quality thin ZnO films.

  9. Dissociated cells of foetal rat pallium grown in culture medium supplemented with noradrenaline: effects on the expression of neuron-specific enolase and cell adhesion molecule L1.

    PubMed

    König, N; Drian, M J; Privat, A; Lamandé, N; Parés-Herbuté, N; Schachner, M

    1986-05-01

    The possible influence of noradrenaline (NA) upon cell differentiation has been studied by comparing NA-supplemented cultures of foetal pallial cells with control cultures grown in normal medium. Two days after plating, the cultures were processed for immunocytochemical detection of either an adhesion molecule and marker of early stages of neuronal differentiation (L1) or a marker expressed at relatively late stages (gamma-enolase). In both cases, the NA supplement reduced the expression of the antigen. The effects were more clear-cut for the late than for the early marker. In conclusion, the NA supplement to the culture medium, in our model, seemed to have a 'differentiation regulating' rather than a 'neurotrophic' function sensu stricto. It remains to be clarified, however, to which extent this finding can be generalized to in vivo situations. PMID:3714115

  10. Heteroepitaxial Film Silicon Solar Cell Grown on Ni-W Foils

    SciTech Connect

    Wee, S. H.; Cantoni, C.; Fanning, T. R.; Teplin, C. W.; Bogorin, D. F.; Bornstein, J.; Bowers, K.; Schroeter, P.; Hasoon, F.; Branz, H. M.; Paranthaman, M. P.; Goyal, A.

    2012-03-01

    Heteroepitaxial semiconductor films on low-cost, flexible metal foil templates are a potential route to inexpensive, high-efficiency solar cells. Here, we report epitaxial growth of Si films on low-cost, flexible, biaxially-textured Ni-W substrates. A robust buffer architecture comprised of multiple epitaxial oxide layers has been developed to grow high quality, heteroepitaxial Si films without any undesired reaction between the Si film and the metal substrate and with a single biaxial texture. XRD analysis including {omega}-scans, {phi}-scans, and pole figures confirms that the buffers and silicon are all epitaxial, with excellent cube-on-cube epitaxy. A photo-conversion efficiency of 1.1% is demonstrated from a proof-of-concept heteroepitaxial film Si solar cell.

  11. Method for Determination of Free Intracellular and Extracellular Methylglyoxal in Animal Cells Grown in Culture

    Microsoft Academic Search

    Frank W. R. Chaplen; William E. Fahl; Douglas C. Cameron

    1996-01-01

    Methylglyoxal is present at low levels in most cells as a by-product of glycolysis and a product of lipid and amino acid catabolism. The most widely accepted method for measurement of methylglyoxal involves the derivatization of methylglyoxal with 1,2-diaminobenzene derivatives, such aso-phenylenediamine, followed by quantification of the resulting quinoxaline with high-performance liquid chromatography (HPLC). Here we describe the modification of

  12. Thermal stability and inactivation of hepatitis C virus grown in cell culture

    Microsoft Academic Search

    Hongshuo Song; Jin Li; Shuang Shi; Ling Yan; Hui Zhuang; Kui Li

    2010-01-01

    BACKGROUND: Hepatitis C virus (HCV) is a blood-borne flavivirus that infects many millions of people worldwide. Relatively little is known, however, concerning the stability of HCV and reliable procedures for inactivating this virus. METHODS: In the current study, the thermostability of cell culture-derived HCV (HCVcc, JFH-1 strain) under different environmental temperatures (37°C, room temperature, and 4°C) and the ability of

  13. Rapid differentiation of NT2 cells in Sertoli–NT2 cell tissue constructs grown in the rotating wall bioreactor

    Microsoft Academic Search

    Samuel Saporta; Alison E. Willing; Rania Shamekh; Paula Bickford; Daniel Paredes; Don F. Cameron

    2004-01-01

    Cell replacement therapy is of great interest as a long-term treatment of neurodegenerative diseases such as Parkinson's disease (PD). We have previously shown that Sertoli cells (SC) provide neurotrophic support to transplants of dopaminergic fetal neurons and NT2N neurons, derived from the human clonal precursors cell line NTera2\\/D1 (NT2), which differentiate into dopaminergic NT2N neurons when exposed to retinoic acid.

  14. Use of cyanobacterial gas vesicles as oxygen carriers in cell culture.

    PubMed

    Sundararajan, Anand; Ju, Lu-Kwang

    2006-10-01

    The gas vesicles isolated from the cells of filamentous cyanobacterium Anabaena flos-aquae were treated and sterilized with glutaraldehyde and then evaluated for their effectiveness as gas carriers in cell culture. Anchorage-dependent Vero cells were grown in a packed bed of microcarrier beads under the perfusion of Dulbecco's Modified Eagle's Medium with 1% serum. The culture medium supplemented with 1.8% (v/v) gas vesicles was found to support a 30% higher maximum glucose utilization rate than the same medium without gas vesicles. The gas vesicle suspension was confirmed to have no apparent effects on cell metabolism in T-flask cultures. The study results indicated that the gas vesicles, with high oxygen carrying capacity, can be used to increase the oxygen supply in cell culture systems. PMID:19002872

  15. Evidence for Autoregulation of Cell Division and Cell Transit in Keratinocytes Grown on Collagen at an Air-Liquid Interface

    Microsoft Academic Search

    Donald K. MacCallum; John H. Lillie

    1990-01-01

    Oral and epidermal rat keratinocytes when cultured on a matrix of type I collagen fibrils at the interface between the gaseous and liquid phases of a culture form a highly ordered stratified squamous epithelium. Autoradiographic studies of cells labeled by tritiated thymidine indicate that the keratinocytes are capable of autoregulating cell division. Early confluent cultures exhibit 51 % of basal

  16. Development of a dose verification system for Vero4DRT using Monte Carlo method.

    PubMed

    Ishihara, Yoshitomo; Sawada, Akira; Nakamura, Mitsuhiro; Miyabe, Yuki; Tanabe, Hiroaki; Kaneko, Shuji; Takayama, Kenji; Mizowaki, Takashi; Kokubo, Masaki; Hiraoka, Masahiro

    2014-01-01

    Vero4DRT is an innovative image-guided radiotherapy system employing a C-band X-ray head with gimbal mechanics. The purposes of this study were to propose specific MC models of the linac head and multileaf collimator (MLC) for the Vero4DRT and to verify their accuracy. For a 6 MV photon beam delivered by the Vero4DRT, a simulation code was implemented using EGSnrc. The linac head model and the MLC model were simulated based on its specification. Next, the percent depth dose (PDD) and beam profiles at depths of 15, 100, and 200 mm were simulated under source-to-surface distance of 900 and 1000 mm. Field size was set to 150 × 150 mm2 at a depth of 100 mm. Each of the simulated dosimetric metrics was then compared with the corresponding measurements by a 0.125 cc ionization chamber. After that, intra- and interleaf leakage, tongue-and-groove, and rounded-leaf profiles were simulated for the static MLC model. Meanwhile, film measurements were performed using EDR2 films under similar conditions to simulation. The measurement for the rounded-leaf profile was performed using the water phantom and the ionization chamber. The leaf physical density and abutting leaf gap were adjusted to obtain good agreement between the simulated intra- and interleaf leakage profiles and measurements. For the MLC model in step-and-shoot cases, a pyramid and a prostate IMRT field were simulated, while film measurements were performed using EDR2. For the linac head, exclusive of MLC, the difference in PDD was < 1.0% after the buildup region. The simulated beam profiles agreed to within 1.3% at each depth. The MLC model has been shown to reproduce dose measurements within 2.5% for static tests. The MLC is made of tungsten alloy with a purity of 95%. The leaf gap of 0.015 cm and the MLC physical density of 18.0 g/ cm3, which provided the best agreement between the simulated and measured leaf leakage, were assigned to our MC model. As a result, the simulated step-and-shoot IMRT dose distributions agreed with the film measurements to within 3.3%, with exception of the penumbra region. We have developed specific MC models of the linac head and the MLC in the Vero4DRT system. The results have demonstrated that our MC models have high accuracy.  PMID:25493521

  17. VeroScience: applying nature's genius to help improve the human condition.

    PubMed

    2013-02-01

    VeroScience is a biotechnology company in Tiverton, Rhode Island, focused on the development of therapies and products to improve human health. The company has a strong pipeline of metabolic disease products and therapies for immunological disorders. A major platform technology of the company, Circadian Neuroendocrine Resetting Therapy, is utilized as a generator of multiple therapeutic strategies to treat a variety of disease states. The circadian timed daily (morning) administration of Cycloset®, a quick release formulation of bromocriptine mesylate, a dopamine agonist, was developed for the treatment of type 2 diabetes using this platform technology. PMID:23641424

  18. Moringa oleifera Lam. (Moringaceae) grown in Nigeria: In vitro antisickling activity on deoxygenated erythrocyte cells

    PubMed Central

    Adejumo, Olufunmilayo E.; Kolapo, Adelodun L.; Folarin, Akintomiwa O.

    2012-01-01

    Context: Traditional medicine, which is more available and affordable for the poor uses medicinal plants for the treatment and management of various ailments, including the sickle cell disease (SCD). About 24 million Nigerians are carriers of this sickled cell gene, while approximately 2.4 million are SCD patients. Moringa oleifera Lam. (Moringaceae) possesses high nutritional value and has been used in folklore medicine to treat various ailments related to pain and inflammation. Chemical, pharmacological and pharmacognostical applications of Moringa oleifera have been reported. Objective: This study investigated the antisickling potential of polar and non-polar extracts of the seed, flower and leaf of Moringa oleifera for the first time. Materials and Methods: Using crude methanol extract, aqueous extract, ethyl acetate and butanol, the in vitro antisickling activities of Moringa oleifera fractions, were evaluated using erythrocyte cells deoxygenated with 2% sodium metabisulphite. p-Hydroxybenzoic acid and normal saline were employed as positive and negative controls. Results: Phytochemical screening revealed the presence of saponins, free anthraquinones, and alkaloids. Extracts of the seed and flower demonstrated a higher (P<0.05) antisickling activity in comparison to the leaf extract. The leaf extract, as well as those of the seed and flower, equally demonstrated a (P<0.05) reversal of sickled erythrocytes. Discussions and Conclusions: These findings suggest that Moringa oleifera may play a role in the management of SCD, by incorporation of its fractions into recipes. More extensive biological evaluations and further studies will be necessary for the chemical characterization of the antisickling principles. PMID:22557922

  19. Expression of putative pathogenicity-related genes in Xylella fastidiosa grown at low and high cell density conditions in vitro.

    PubMed

    Scarpari, Leandra M; Lambais, Marcio R; Silva, Denise S; Carraro, Dirce M; Carrer, Helaine

    2003-05-16

    Xylella fastidiosa is the causal agent of economically important plant diseases, including citrus variegated chlorosis and Pierce's disease. Hitherto, there has been no information on the molecular mechanisms controlling X. fastidiosa-plant interactions. To determine whether predicted open reading frames (ORFs) encoding putative pathogenicity-related factors were expressed by X. fastidiosa 9a5c cells grown at low (LCD) and high cell density (HCD) conditions in liquid modified PW medium, reverse Northern blot hybridization and reverse transcription-polymerase chain reaction (RT-PCR) experiments were performed. Our results indicated that ORFs XF2344, XF2369, XF1851 and XF0125, encoding putative Fur, GumC, a serine-protease and RsmA, respectively, were significantly suppressed at HCD conditions. In contrast, ORF XF1115, encoding putative RpfF, was significantly induced at HCD conditions. Expressions of ORFs XF2367, XF2362 and XF0290, encoding putative GumD, GumJ and RpfA, respectively, were detected only at HCD conditions, whereas expression of ORF XF0287, encoding putative RpfB was detected only at LCD conditions. Bioassays with an Agrobacterium traG::lacZ reporter system indicated that X. fastidiosa does not synthesize N-acyl-homoserine lactones, whereas bioassays with a diffusible signal factor (DSF)-responsive Xanthomonas campestris pv. campestris mutant indicate that X. fastidiosa synthesizes a molecule similar to DSF in modified PW medium. Our data also suggest that the synthesis of the DSF-like molecule and fastidian gum by X. fastidiosa is affected by cell density in vitro. PMID:12757950

  20. In vitro study of endothelial cells lining vascular grafts grown within the recipient's peritoneal cavity.

    PubMed

    Zhang, Zhi-Xiong; Xi, Ting-Fei; Wang, Ying-Jun; Chen, Xiao-Song; Zhang, Jian; Wang, Chun-Ren; Gu, Yong-Quan; Chen, Liang; Li, Jian-Xin; Chen, Bing

    2008-06-01

    A living-tissue conduit with strong mechanical properties was used to produce small-diameter vessels. To improve blood compatibility, a shear-resistant confluent monolayer endothelium was formed on the luminal surface of the conduit. Under mechanical stimulation induced by pulsatile flow in a bioreactor, abrupt high-flow shear stress of 15.3 +/- 4.6 dynes/cm2 was applied to endothelial cells (ECs) seeded onto the lumen of a living-tissue conduit after 2 days of static culture. Scanning electron microscopy images revealed that most of the ECs were washed off after 3 days of dynamic culture. When shear stress was increased stepwise from 1.5 +/- 0.8 to 15.3 +/- 4.6 dynes/cm2 and applied to the ECs, scanning electron microscopy images of the luminal surface revealed that the confluent monolayer ECs were highly elongated and oriented to the flow direction, similar to findings in natural arteries in vivo. The results indicated that in vitro flow conditions played a key role in determining the durability of the EC layer. Careful design of the bioreactor and careful selection of the culture conditions will greatly improve the chances of producing a useful anti-thrombogenic surface for tissue-engineered small-diameter vessels. PMID:18498218

  1. Vero cytotoxin-producing Escherichia coli O157 gastroenteritis in farm visitors, North Wales.

    PubMed

    Payne, Christopher J I; Petrovic, Marko; Roberts, Richard J; Paul, Ashish; Linnane, Eithne; Walker, Mark; Kirby, David; Burgess, Anthony; Smith, Robert M M; Cheasty, Thomas; Willshaw, Geraldine; Salmon, Roland L

    2003-05-01

    An outbreak of Vero cytotoxin-producing Escherichia coli O157 (VTEC O157) gastroenteritis in visitors to an open farm in North Wales resulted in 17 primary and 7 secondary cases of illness. E. coli O157 Vero cytotoxin type 2, phage type 2 was isolated from 23 human cases and environmental animal fecal samples. A case-control study of 16 primary case-patients and 36 controls (all children) showed a significant association with attendance on the 2nd day of a festival, eating ice cream or cotton candy (candy floss), and contact with cows or goats. On multivariable analysis, only the association between illness and ice cream (odds ratio [OR]=11.99, 95% confidence interval [CI] 1.04 to 137.76) and cotton candy (OR=51.90, 95% CI 2.77 to 970.67) remained significant. In addition to supervised handwashing, we recommend that foods on open farms only be eaten in dedicated clean areas and that sticky foods be discouraged. PMID:12737734

  2. Interaction between submicron COD crystals and renal epithelial cells

    PubMed Central

    Peng, Hua; Ouyang, Jian-Ming; Yao, Xiu-Qiong; Yang, Ru-E

    2012-01-01

    Objectives This study aims to investigate the adhesion characteristics between submicron calcium oxalate dihydrate (COD) with a size of 150 ± 50 nm and African green monkey kidney epithelial cells (Vero cells) before and after damage, and to discuss the mechanism of kidney stone formation. Methods Vero cells were oxidatively injured by hydrogen peroxide to establish a model of injured cells. Scanning electron microscopy was used to observe Vero–COD adhesion. Inductively coupled plasma emission spectrometry was used to quantitatively measure the amount of adhered COD microcrystals. Nanoparticle size analyzer and laser scanning confocal microscopy were performed to measure the change in the zeta potential on the Vero cell surface and the change in osteopontin expression during the adhesion process, respectively. The level of cell injury was evaluated by measuring the changes in malonaldehyde content, and cell viability during the adhesion process. Results The adhesion capacity of Vero cells in the injury group to COD microcrystals was obviously stronger than that of Vero cells in the control group. After adhesion to COD, cell viability dropped, both malonaldehyde content and cell surface zeta potential increased, and the fluorescence intensity of osteopontin decreased because the osteopontin molecules were successfully covered by COD. Submicron COD further damaged the cells during the adhesion process, especially for Vero cells in the control group, leading to an elevated amount of attached microcrystals. Conclusion Submicron COD can further damage injured Vero cells during the adhesion process. The amount of attached microcrystals is proportional to the degree of cell damage. The increased amount of microcrystals that adhered to the injured epithelial cells plays an important role in the formation of early-stage kidney stones. PMID:22973095

  3. Variable temperature carrier dynamics in bulk (In)GaAsNSb materials grown by MOVPE for multi-junction solar cells

    NASA Astrophysics Data System (ADS)

    Sin, Yongkun; Lingley, Zachary; LaLumondiere, Stephen; Wells, Nathan; Lotshaw, William; Moss, Steven C.; Kim, Tae Wan; Mawst, Luke J.; Kuech, Thomas F.

    2014-03-01

    III-V multi-junction solar cells are typically based on a triple-junction design that consists of an InGaP top junction, a GaAs middle junction, and a bottom junction that employs a 1 - 1.25 eV material grown on GaAs substrates. The most promising 1 - 1.25 eV material that is currently under extensive investigation is bulk dilute nitride such as (In)GaAsNSb lattice matched to GaAs substrates. The approach utilizing dilute nitrides has a great potential to achieve high performance triple-junction solar cells as recently demonstrated by Wiemer, et al., who achieved a record efficiency of 43.5% from multi-junction solar cells including MBE-grown dilute nitride materials [1]. Although MOVPE is a preferred technique over MBE for III-V multi-junction solar cell manufacturing, MOVPEgrown dilute nitride research is at its infancy compared to MBE-grown dilute nitride. In particular, carrier dynamics studies are indispensible in the optimization of MOVPE materials growth parameters to obtain improved solar cell performance. For the present study, we employed time-resolved photoluminescence (TR-PL) techniques to study carrier dynamics in MOVPE-grown bulk dilute nitride InGaAsN materials (Eg = 1 - 1.25 eV at RT) lattice matched to GaAs substrates. In contrast to our earlier samples that showed high background C doping densities, our current samples grown using different metalorganic precursors at higher growth temperatures showed a significantly reduced background doping density of ~ 1017 /cm3. We studied carrier dynamics in (In)GaAsNSb double heterostructures (DH) with different N compositions at room temperature. Post-growth annealing yielded significant improvements in carrier lifetimes of (In)GaAsNSb double heterostructure (DH) samples. Carrier dynamics at various temperatures between 10 K and RT were also studied from (In)GaAsNSb DH samples including those samples grown on different orientation substrates.

  4. Expression Profile of Drug and Nutrient Absorption Related Genes in Madin-Darby Canine Kidney (MDCK) Cells Grown under Differentiation Conditions

    PubMed Central

    Quan, Yong; Jin, Yisheng; Faria, Teresa N.; Tilford, Charles A.; He, Aiqing; Wall, Doris A.; Smith, Ronald L.; Vig, Balvinder S.

    2012-01-01

    The expression levels of genes involved in drug and nutrient absorption were evaluated in the Madin-Darby Canine Kidney (MDCK) in vitro drug absorption model. MDCK cells were grown on plastic surfaces (for 3 days) or on Transwell® membranes (for 3, 5, 7, and 9 days). The expression profile of genes including ABC transporters, SLC transporters, and cytochrome P450 (CYP) enzymes was determined using the Affymetrix® Canine GeneChip®. Expression of genes whose probe sets passed a stringent confirmation process was examined. Expression of a few transporter (MDR1, PEPT1 and PEPT2) genes in MDCK cells was confirmed by RT-PCR. The overall gene expression profile was strongly influenced by the type of support the cells were grown on. After 3 days of growth, expression of 28% of the genes was statistically different (1.5-fold cutoff, p < 0.05) between the cells grown on plastic and Transwell® membranes. When cells were differentiated on Transwell® membranes, large changes in gene expression profile were observed during the early stages, which then stabilized after 5–7 days. Only a small number of genes encoding drug absorption related SLC, ABC, and CYP were detected in MDCK cells, and most of them exhibited low hybridization signals. Results from this study provide valuable reference information on endogenous gene expression in MDCK cells that could assist in design of drug-transporter and/or drug-enzyme interaction studies, and help interpret the contributions of various transporters and metabolic enzymes in studies with MDCK cells. PMID:24300234

  5. Changes of ribulose bisphosphate carboxylase/oxygenase content, ribulose bisphosphate concentration, and photosynthetic activity during adaptation of high-CO/sub 2/ grown cells to low-CO/sub 2/ conditions in Chlorella pyrenoidosa

    SciTech Connect

    Yokota, A.; Canvin, D.T.

    1986-02-01

    Changes of some photosynthetic properties of high-CO/sub 2/ grown cells of Chlorella pyrenoidosa during adaptation to low-CO/sub 2/ conditions have been investigated. The K/sub m/ value of photosynthesis of the high-CO/sub 2/ grown cells for dissolved inorganic carbon was 3.3 millimolar and decreased to 25 to 30 micromolar within 4 hours after transferring to air. In the presence of saturating CO/sub 2/ concentrations the photosynthetic activity of the high-CO/sub 2/ grown cells was 1.5 times as high as that of the low-CO/sub 2/ grown cells. There was a significant rise of the photosynthetic activity during adaptation of the high-CO/sub 2/ grown cells to air, followed by a steady decrease. The activity of ribulose 1,5-bisphosphate carboxylase/oxygenase in both the high and low-CO/sub 2/ grown cells was close to the photosynthetic activity of the cells. The concentration of ribulose 1,5-bisphosphate (RuBP) was higher in the low-CO/sub 2/ adapting and low-CO/sub 2/ grown celsl than in the high-CO/sub 2/ grown cells regardless of the photosynthetic rate. This seems to be due to an increased RuBP regeneration activity during adaptation followed by maintenance of the new higher concentration. The RuBP level always exceeded the concentration of ribulose 1,5-bisphosphate carboxylase/oxygenase RuBP binding sites in both the high- and low-CO/sub 2/ grown cells at any dissolved inorganic carbon concentration.

  6. Properties of an nC:P\\/pSi carbon-based photovoltaic cell grown by radio frequency plasma-enhanced chemical vapor deposition at room temperature

    Microsoft Academic Search

    M. Rusop; T. Soga; T. Jimbo

    2006-01-01

    The phosphorus-doped amorphous carbon (n-C:P) films were grown by radiofrequency (RF) power-assisted plasma-enhanced chemical vapor deposition (PECVD) at room temperature using a solid phosphorus target. The influence of phosphorus doping on the material properties of n-C:P based on the results of simultaneous characterization are reported. Moreover, solar cell properties such as series resistance, short-circuit current density, open-circuit current voltage, fill

  7. Porous, single crystalline titanium nitride nanoplates grown on carbon fibers: excellent counter electrodes for low-cost, high performance, fiber-shaped dye-sensitized solar cells.

    PubMed

    Chen, Liang; Dai, Hui; Zhou, Yong; Hu, Yingjie; Yu, Tao; Liu, Jianguo; Zou, Zhigang

    2014-11-28

    An excellent, platinum free fiber counter electrode (CE) was successfully fabricated, consisting of porous, single crystalline titanium nitride (TiN) nanoplates grown on carbon fibers (CF). The fiber-shaped dye-sensitized solar cells (FDSSCs) based on the TiN-CF CE show a high conversion efficiency of 7.20%, comparable or even superior to that of the Pt wire (6.23%). PMID:25068835

  8. Bioremoval and recovery of Cd(II) by Pseudoalteromonas sp. SCSE709-6: Comparative study on growing and grown cells.

    PubMed

    Zhou, Weizhi; Liu, Dongsheng; Zhang, Hai'ou; Kong, Wenqian; Zhang, Yuzhong

    2014-08-01

    Comparison of the bioremoval and recovery of Cd(II) by growing and grown marine bacterium Pseudoalteromonas sp. SCSE709-6 was performed in batch systems. Bioremoval with growing cells (Sorption I) showed better performance at low Cd(II) concentrations, whereas bioremoval with grown cells (Sorption II) had significant advantages in both removal efficiency and time consumption at high Cd(II) concentrations. The optimal pH was higher for Sorption I than for Sorption II for achieving the maximum Cd(II) removal efficiency. Complete desorption was achieved using either Na2EDTA or HNO3 as eluent. Cd(II) adsorbed on grown cells had higher tendency to be desorbed. Na2EDTA was a preferable eluent for the recycling biomaterials, whereas HNO3 performed better for the final security disposal of sludge. For Sorption II, both Langmuir and Freundlich isotherms well explained the biosorption behavior, and the pseudo-second-order model better expressed biosorption and desorption kinetics. PMID:24565875

  9. 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.

  10. High-efficiency (AlGa)As\\/GaAs solar cells grown by MOVPE using TBAs at low-temperatures and low V\\/III-ratios

    Microsoft Academic Search

    C Agert; F Dimroth; U Schubert; A. W Bett; S Leu; W Stolz

    2001-01-01

    The alternative As-precursor tertiarybutylarsine (TBAs) is used to grow (AlGa)As–GaAs heteroface solar cell structures. In a horizontal reactor (AIX200) a low growth temperature of 625°C and a low V\\/III-ratio of 10 was used. Solar cell structures using a arsine (AsH3)-based MOVPE process were grown in a multi-wafer reactor (AIX2600G3) using growth temperatures of 700°C and a V\\/III-ratio of 31. The

  11. InGaAs/GaAsP superlattice solar cells with reduced carbon impurity grown by low-temperature metal-organic vapor phase epitaxy using triethylgallium

    NASA Astrophysics Data System (ADS)

    Fujii, Hiromasa; Toprasertpong, Kasidit; Sodabanlu, Hassanet; Watanabe, Kentaroh; Sugiyama, Masakazu; Nakano, Yoshiaki

    2014-11-01

    In this paper, we investigated the effects of carbon incorporation on photovoltaic performance of InGaAs/GaAsP superlattice (SL) solar cells grown by low-temperature MOVPE (LT-MOVPE), which is required for stable SL growth on vicinal substrates. Using trimethylgallium (TMGa) as the gallium precursor, methyl radicals formed by its pyrolysis tend to be absorbed on the surface at low temperature, causing severe carbon incorporation and p-type background doping. High background carrier concentration flattens the band-lineup of the intrinsic region and blocks the carrier transport across the SLs, and resulted in serious degradation of photocurrent. Intentional sulfur doping to cancel out the background doping and hence to recover the built-in field greatly improved the cell performance, but was found to require very precise control of doping level to achieve an exact compensation doping condition. Use of triethylgallium (TEGa) instead of TMGa much reduced the carbon incorporation at low temperature and significantly enhanced the photocurrent extraction without sulfur doping treatment. By thinning GaAsP barriers to 3 nm to facilitate efficient tunneling transport, a 50-period SL cell with bandgap of 1.22 eV grown on 6°-miscut substrates achieved 1.13 times higher efficiency with 31% current enhancement as middle cell performance than a GaAs reference cell.

  12. SU-E-J-129: A Strategy to Consolidate the Image Database of a VERO Unit Into a Radiotherapy Management System

    SciTech Connect

    Yan, Y; Medin, P; Yordy, J; Zhao, B; Jiang, S [UT Southwestern Medical Center, Dallas, TX (United States)

    2014-06-01

    Purpose: To present a strategy to integrate the imaging database of a VERO unit with a treatment management system (TMS) to improve clinical workflow and consolidate image data to facilitate clinical quality control and documentation. Methods: A VERO unit is equipped with both kV and MV imaging capabilities for IGRT treatments. It has its own imaging database behind a firewall. It has been a challenge to transfer images on this unit to a TMS in a radiation therapy clinic so that registered images can be reviewed remotely with an approval or rejection record. In this study, a software system, iPump-VERO, was developed to connect VERO and a TMS in our clinic. The patient database folder on the VERO unit was mapped to a read-only folder on a file server outside VERO firewall. The application runs on a regular computer with the read access to the patient database folder. It finds the latest registered images and fuses them in one of six predefined patterns before sends them via DICOM connection to the TMS. The residual image registration errors will be overlaid on the fused image to facilitate image review. Results: The fused images of either registered kV planar images or CBCT images are fully DICOM compatible. A sentinel module is built to sense new registered images with negligible computing resources from the VERO ExacTrac imaging computer. It takes a few seconds to fuse registered images and send them to the TMS. The whole process is automated without any human intervention. Conclusion: Transferring images in DICOM connection is the easiest way to consolidate images of various sources in your TMS. Technically the attending does not have to go to the VERO treatment console to review image registration prior delivery. It is a useful tool for a busy clinic with a VERO unit.

  13. 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.

  14. PROCUSTE1 Encodes a Cellulose Synthase Required for Normal Cell Elongation Specifically in Roots and Dark-Grown Hypocotyls of Arabidopsis

    PubMed Central

    Fagard, Mathilde; Desnos, Thierry; Desprez, Thierry; Goubet, Florence; Refregier, Guislaine; Mouille, Gregory; McCann, Maureen; Rayon, Catherine; Vernhettes, Samantha; Höfte, Herman

    2000-01-01

    Mutants at the PROCUSTE1 (PRC1) locus show decreased cell elongation, specifically in roots and dark-grown hypocotyls. Cell elongation defects are correlated with a cellulose deficiency and the presence of gapped walls. Map-based cloning of PRC1 reveals that it encodes a member (CesA6) of the cellulose synthase catalytic subunit family, of which at least nine other members exist in Arabidopsis. Mutations in another family member, RSW1 (CesA1), cause similar cell wall defects in all cell types, including those in hypocotyls and roots, suggesting that cellulose synthesis in these organs requires the coordinated expression of at least two distinct cellulose synthase isoforms. PMID:11148287

  15. 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.

  16. Differences in excitation energy transfer of Arthrospira platensis cells grown in seawater medium and freshwater medium, probed by time-resolved fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Arba, Muhammad; Aikawa, Shimpei; Niki, Kenta; Yokono, Makio; Kondo, Akihiko; Akimoto, Seiji

    2013-11-01

    Excitation energy transfer of Arthrospira platensis cells grown in f/2 medium (a high salinity medium) and SOT medium (a control) was investigated by steady-state and time-resolved spectroscopies. Growth in f/2 medium induced changes in absorption and fluorescence spectra as well as in the energy transfer pathways. Excitation energy captured by phycobilisome (PBS) was transferred directly to photosystem (PS) I, instead of being first transferred to an intermediate (PBS ? PSII ? PSI), as observed in SOT medium. The respiration rate increased while photosynthetic rate reduced in f/2 medium. Possible causes of the differences in light-harvesting and energy-transfer processes between the two media are discussed.

  17. Sensitive and rapid detection of Vero toxin-producing Escherichia coli using loop-mediated isothermal amplification

    Microsoft Academic Search

    Yukiko Hara-Kudo; Jiro Nemoto; Kayoko Ohtsuka; Yuko Segawa; Kosuke Takatori; Tadashi Kojima; Masanari Ikedo

    2007-01-01

    A loop-mediated isothermal amplification (LAMP) assay was developed to detect Vero toxin (VT)-producing Escherichia coli rapidly (within 60 min). The 24 strains of VT-producing E. coli were successfully amplified, but 6 strains of non-VT-producing E. coli and 46 bacterial species other than E. coli were not. The sensitivity of the LAMP assay was found to be >0.7 c.f.u. per test

  18. 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.

  19. Significant changes in cell and chloroplast development in young wheat leaves (Triticum aestivum cv Hereward) grown in elevated CO{sub 2}

    SciTech Connect

    Robertson, E.J.; Leech, R.M. [Univ. of York, Heslington (United Kingdom)

    1995-01-01

    Cell and chloroplast development were characterized in young Triticum aestivum cv Hereward leaves grown at ambient (350 {mu}L L{sup {minus}1}) or at elevated (650 {mu}L L{sup {minus}1}) CO{sub 2}. In elevated CO{sub 2}, cell and chloroplast expansion was accelerated by 10 and 25%, respectively, in the first leaf of 7-d-old wheat plants without disruption to the leaf developmental pattern. Elevated CO{sub 2} did not affect the number of chloroplasts in relation to mesophyll cell size or the linear relationship between chloroplast number or size and mesophyll cell size. No major changes in leaf anatomy or in chloroplast ultrastructure were detected as a result of growth in elevated CO{sub 2}, but there was a marked reduction in starch accumulation. In leaf sections fluorescently tagged antisera were used to visualize and quantitate the amount of cytochrome f, the {alpha}- and {beta}-subunits of the coupling factor 1 in ATP synthase, D1 protein of the photosystem II reaction center, the 33-kD protein of the extrinsic oxygen-evolving complex, subunit II of photosystem I, and ribulose-1,5-biphosphate carboxylase/oxygenase. A significant finding was that in 10 to 20% of the mesophyll cells grown in elevated CO{sub 2} the 33-kD protein of the extrinsic oxygen-evolving complex of photosystem II and cytochrome f were deficient by 75%, but the other proteins accumulated normally. 29 refs., 6 figs., 2 tabs.

  20. A vero cell derived combined vaccine against sheep pox and Peste des Petits ruminants for sheep.

    PubMed

    Chaudhary, S S; Pandey, K D; Singh, R P; Verma, P C; Gupta, P K

    2009-04-28

    The combined sheep pox and Peste des Petits ruminants (PPR) vaccine was prepared in lyophilized form containing recommended doses of both vaccine viruses. Safety and immunogenicity of this combined vaccine was evaluated in sheep. Sheep immunized subcutaneously with 1ml of live attenuated vaccine consisting of 10(3)TCID(50) each of sheep pox virus (SPV) Romanian Fanar (RF) strain and Peste des Petits ruminants virus (PPRV-Sungri/96 strain) were monitored for clinical and serological responses for a period of four weeks post immunization (pi) and two week post challenge (pc). Specific antibodies directed to sheep pox virus could be demonstrated by indirect ELISA and serum neutralization test (SNT). Competitive ELISA and SNT were used for demonstration of antibodies to PPR virus. All the immunized animals resisted challenge with virulent SPV or PPRV on day 30pi, while control animals developed characteristic signs of disease. Specific virus could be detected in the unvaccinated control animals after challenge but not from any of the immunized sheep. Combined vaccine was found to be safe and potent as evident from sero conversion as well as challenge studies in sheep. This indicates that component vaccines did not interfere each other and can be used in target population for economic vaccination strategies. PMID:19428860

  1. A vero cell derived combined vaccine against sheep pox and Peste des Petits ruminants for sheep

    Microsoft Academic Search

    S. S. Chaudhary; K. D. Pandey; R. P. Singh; P. C. Verma; P. K. Gupta

    2009-01-01

    The combined sheep pox and Peste des Petits ruminants (PPR) vaccine was prepared in lyophilized form containing recommended doses of both vaccine viruses. Safety and immunogenicity of this combined vaccine was evaluated in sheep. Sheep immunized subcutaneously with 1ml of live attenuated vaccine consisting of 103TCID50 each of sheep pox virus (SPV) Romanian Fanar (RF) strain and Peste des Petits

  2. Lactoferrin inhibits herpes simplex virus type 1 adsorption to Vero cells

    Microsoft Academic Search

    Magda Marchetti; Catia Longhi; Maria Pia Conte; Silvia Pisani; Piera Valenti; Lucilla Seganti

    1996-01-01

    This paper describes the ability of human and bovine lactoferrins (HLf; BLf), iron-binding proteins belonging to the non-immune defense system, to interfere with herpes simplex virus type 1 (HSV-1) infection. Since lactoferrins are known to bind to heparan sulphate proteoglycans and to low density lipoprotein receptor, which in turn act as binding sites for the initial interaction of HSV-1 with

  3. Genetic analysis of the herpes simplex virus type 1 UL9 gene: isolation of a LacZ insertion mutant and expression in eukaryotic cells.

    PubMed

    Malik, A K; Martinez, R; Muncy, L; Carmichael, E P; Weller, S K

    1992-10-01

    HSV-1 host range mutants in complementation group 1-36 (hr27 and hr156) whose mutations map in the UL9 gene, encoding the origin binding protein, are unable to form plaques or synthesize viral DNA or late viral proteins when grown in nonpermissive Vero cells (Carmichael, E. P., Kosovsky, M. J., Weller, S. K., 1988, J. Virol. 62, 91-99). These defects are complemented efficiently by growth in the permissive cell line, S22, which contains the wild type version of several HSV genes including UL9. In this report the precise nature and location of the lesions in host range mutants hr27 and hr156 were determined by DNA sequencing; both mutants were found to contain identical single-base-pair substitutions at codons 309 and 311 in the UL9 open reading frame. This region lies within the putative helicase domain of the UL9 protein. The UL9 gene was disrupted by the insertion of an insertional mutagen ICP6::lacZ in which the Escherichia coli lacZ gene is expressed under control of the viral ICP6 promoter. Hr94, a viral mutant containing this insertion, does not form plaques or synthesize viral DNA when grown in Vero cells, although both defects are complemented efficiently on permissive cell lines. These results confirm that the UL9 gene product is essential for viral growth and DNA replication. Furthermore, since no detectable UL9 protein is synthesized in hr94-infected cells, this virus provides a useful genetic background for further structure-function analysis since no potentially interfering nonfunctional UL9 protein will be expressed. We have expressed the UL9 open reading frame under the control of the strong and inducible HSV-1 ICP6 promoter and have derived Vero cell lines containing variable copy numbers of the ICP6::UL9 construct. Cells whose copy number of this construct exceeded approximately 120 are unable to support efficient plaque formation by wild-type virus. Cell lines with low copy numbers of this construct are able to complement hr27, hr156, and hr94. PMID:1325702

  4. The Influence of Oxygen Tension and pH on the Expression of Plateletderived Endothelial Cell Growth Factor\\/Thymidine Phosphorylase in Human Breast Tumor Cells Grown in Vitroand in Vivo

    Microsoft Academic Search

    Leigh Griffiths; Gabi U. Dachs; Roy Bicknell; Adrian L. Harris; Ian J. Stratford

    We report that hypoxia regulates and influences the level ofthe angiogenic enzymeplatelet.derivedendothelialcell growth factor (PD-ECGF),also called thymidine phosphorylase, in vitro and in vivo. Levels of PD.ECGF protein increased 6-fold in the breast cancer cell line MDA 231 after 16 h of growth in 0.3% oxygen. A simultaneous increase in enzyme activity was observed.linmunohistochemical staining ofMDA 231tumors grown in nu\\/nu mice

  5. GROWTH CHARACTERISTICS, MORPHOLOGY, AND PHOSPHOLIPID COMPOSITION OF HUMAN TYPE 2 PULMONARY ALVEOLAR CELLS GROWN IN A COLLAGEN-FREE MICROENVIRONMENT

    EPA Science Inventory

    Human lung epithelial cells have been cultured and characterized for phospholipid content. Any residual fibroblasts were removed by selective trypsinization within the first 48 hours in culture. Epithelial cells were serially subpassaged when cultures reached ca. 80% confluency. ...

  6. Development of crystalline peroxisomes in methanol-grown cells of the yeast Hansenula polymorpha and its relation to environmental conditions

    Microsoft Academic Search

    M. Veenhuis; J. P. van Dijken; S. A. F. Pilon; W. Harder

    1978-01-01

    The development of peroxisomes has been studied in cells of the yeast Hansenula polymorpha during growth on methanol in batch and chemostat cultures. During bud formation, new peroxisomes were generated by the separation of small peroxisomes from mature organelles in the mother cells. The number of peroxisomes migrating to the buds was dependent upon environmental conditions. Aging of cells was

  7. Structural Complexity of Non-acid Glycosphingolipids in Human Embryonic Stem Cells Grown under Feeder-free Conditions*

    PubMed Central

    Barone, Angela; Benktander, John; ?ngström, Jonas; Aspegren, Anders; Björquist, Petter; Teneberg, Susann; Breimer, Michael. E.

    2013-01-01

    Due to their pluripotency and growth capability, there are great expectations for human embryonic stem cells, both as a resource for functional studies of early human development and as a renewable source of cells for use in regenerative medicine and transplantation. However, to bring human embryonic stem cells into clinical applications, their cell surface antigen expression and its chemical structural complexity have to be defined. In the present study, total non-acid glycosphingolipid fractions were isolated from two human embryonic stem cell lines (SA121 and SA181) originating from leftover in vitro fertilized human embryos, using large amounts of starting material (1 × 109 cells/cell line). The total non-acid glycosphingolipid fractions were characterized by antibody and lectin binding, mass spectrometry, and proton NMR. In addition to the globo-series and type 1 core chain glycosphingolipids previously described in human embryonic stem cells, a number of type 2 core chain glycosphingolipids (neo-lactotetraosylceramide, the H type 2 pentaosylceramide, the Lex pentaosylceramide, and the Ley hexaosylceramide) were identified as well as the blood group A type 1 hexaosylceramide. Finally, the mono-, di-, and triglycosylceramides were characterized as galactosylceramide, glucosylceramide, lactosylceramide, galabiaosylceramide, globotriaosylceramide, and lactotriaosylceramide. Thus, the glycan diversity of human embryonic stem cells, including cell surface immune determinants, is more complex than previously appreciated. PMID:23404501

  8. 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, spreading, migration and matrix invasion (what has also been confirmed by our results). It may, perhaps, be the result of myeloid-cancer cell hybrid formation, or cancer cells mimicking macrophages phenotype, owing to various proteins secreted by macrophages. PMID:22353646

  9. The effect of cytochalasin B on chondrogenesis in chick limb-bud mesoderm cells grown in vitro

    Microsoft Academic Search

    Curtis L. Parker; Robert A. Finch; W. Craig Hooper

    1978-01-01

    Summary  Cytochalasin B (CB) has been shown to have many biological effects on cultured cells. We report that an initial 48-hr treatment\\u000a of freshly plated chick embryo limb mesoderm cells with CB irreversibly inhibits chondrogenesis. A slight inhibition in the\\u000a amount of matrix is seen when limb cells are allowed to grow in culture for 24 hr prior to treatment for

  10. Improved Performance of GaInNAs Solar Cells Grown by Molecular-Beam Epitaxy Using Increased Growth Rate Instead of Surfactants

    SciTech Connect

    Ptak, A. J.; France, R.; Jiang, C. S.; Romero, M. J.

    2009-01-01

    GaInNAs is potentially useful for increasing the conversion efficiency of multijunction solar cells if low photocurrents and photovoltages can be increased. Wide-depletion width devices generate significant photocurrents using an n-i-p structure grown by molecular-beam epitaxy, but these wide depletion widths are only realized in a region of parameter space that leads to rough surface morphologies. Surfactants are effective at reducing the surface roughness, but lead to increased defect densities and changes in the net acceptor or donor concentration. Here, we show that increasing the growth rate of GaInNAs solar cells leads to smooth surfaces without the use of a surfactant, even at high In compositions and substrate temperatures. No degradation in material quality is observed when increasing the growth rate from 1.5 to 3.0 {micro}m/h, but a shunt resistance does appear for the high-growth-rate samples. This shunt is attributed to increased spitting of the Ga cell, leading to an increase in the oval defect density, at the higher effusion cell temperatures used to achieve high growth rates. As with the case of Bi in GaInNAs, increased growth rates also appear to increase the net donor concentration, but it is not clear if these effects have the same cause.

  11. 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.

  12. Hypoxic conditions and iron restriction affect the cell-wall proteome of Candida albicans grown under vagina-simulative conditions

    Microsoft Academic Search

    Grazyna J. Sosinska; Groot de P. W. J; M. J. Teixeira De Mattos; H. L. Dekker; Koster de C. G; K. J. Hellingwerf; F. M. Klis

    2008-01-01

    Proteins that are covalently linked to the skeletal polysaccharides of the cell wall of Candida albicans play a major role in the colonization of the vaginal mucosal surface, which may result in vaginitis. Here we report on the variability of the cell-wall proteome of C. albicans as a function of the ambient O-2 concentration and iron availability. For these studies,

  13. Improved conversion efficiency of as-grown InGaN/GaN quantum-well solar cells for hybrid integration

    NASA Astrophysics Data System (ADS)

    Valdueza-Felip, Sirona; Mukhtarova, Anna; Grenet, Louis; Bougerol, Catherine; Durand, Christophe; Eymery, Joel; Monroy, Eva

    2014-03-01

    We report on the photovoltaic characteristics of solar cells based on 15 and 30 InxGa1-xN/GaN (x = 0.10 and 0.19) multiquantum wells (MQWs) grown on sapphire. Doubling the number of MQWs increases the peak external quantum efficiency by a factor of 2 for both In contents. Devices with 19% In, with a spectral cutoff at 465 nm, exhibit an open-circuit voltage of 1.7 V and a short-circuit current density of 3.00 mA/cm2 under 1 sun AM1.5G illumination, leading to a conversion efficiency of 2.00%, making them promising for hybrid integration with non-III-nitride photovoltaic devices.

  14. Failure of propagation of human norovirus in intestinal epithelial cells with microvilli grown in three-dimensional cultures

    PubMed Central

    Takanashi, Sayaka; Saif, Linda J.; Hughes, John H.; Meulia, Tea; Jung, Kwonil; Scheuer, Kelly A.; Wang, Qiuhong

    2013-01-01

    Human noroviruses (HuNoVs) are a leading cause of acute gastroenteritis. Establishment of a cell culture system for in vitro HuNoV growth remains challenging. Replication of HuNoVs in human intestinal cell lines (INT-407 and Caco-2) that differentiate to produce microvilli in rotation wall vessel (RWV) three-dimensional cultures has been reported (Straub et al., Emerg Infect Dis 13:396–403 2007, J Water Health 9:225–240 2011, and Water Sci Technol 67:863–868 2013). We used a similar RWV system, intestinal cell lines, and the same (Genogroup [G] I.1) plus additional (GII.4 and GII.12) HuNoV strains to test the system’s reproducibility and to expand the earlier findings. Apical microvilli were observed on the surface of both cell lines by light and electron microscopy. However, none of the cell types tested resulted in productive viral replication of any of the HuNoV strains, as confirmed by plateau or declining viral RNA titers in the supernatants and cell lysates of HuNoV-infected cells, determined by real-time reverse transcription PCR. These trends were the same when culture supplements were added that have been reported to be effective for replication of other fastidious enteric viruses in vitro. Additionally, by confocal microscopy and orthoslice analysis, viral capsid proteins were mainly observed above the actin filament signals, which suggested that the majority of viral antigens were on the cell surface. We conclude that even intestinal cells displaying microvilli were not sufficient to support HuNoV replication under the conditions tested. PMID:23974469

  15. 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 ?-tricalcium phosphate (?-TCP) was coated on the Mg-3AI-1Zn alloy by alkali-heat treatment technique. The human bone-derived cells (SaOS-2) were cultured on (?-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 (?-TCP)-Mg-3AI-1Zn induced significant osteogenesis. SaOS-2 cell proliferation was improved by ?-TCP coating. Moreover, the (?-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 (?-TCP)-Mg-3AI-1Zn. These results suggest that ?-TCP coating may contribute to successful osteoblast function on Mg alloy surface. (?-TCP)-Mg-3AI-1Zn may upregulate cell proliferation via Shc and ERK1/2 MAPK signaling in SaOS-2 osteoblasts grown on Mg alloy surface. PMID:25783501

  16. Stability of single and tandem junction a-Si:H solar cells grown using the ECR process

    SciTech Connect

    Dalal, V.L.; Maxson, T.; Girvan, R.; Haroon, S.

    1997-07-01

    The authors report on the fabrication and stability tests of single junction a-Si:H, and tandem junction a-Si:H/A-Si:H solar cells using the ECR process under high hydrogen dilution (H-ECR process). They show that devices with high fill factors can be made using the H-ECR process. They also report on the stability studies of the solar cells under 1 and 2-sun illumination conditions. The solar cells show very little degradation even after 500 hours of illumination under 2 x sunlight illumination.

  17. 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.

  18. A549 Lung Epithelial Cells Grown as Three-Dimensional Aggregates: Alternative Tissue Culture Model for Pseudomonas aeruginosa Pathogenesis

    Microsoft Academic Search

    A. J. Carterson; K. Honer zu Bentrup; C. M. Ott; M. S. Clarke; D. L. Pierson; C. R. Vanderburg; K. L. Buchanan; C. A. Nickerson; M. J. Schurr

    2005-01-01

    A three-dimensional (3-D) lung aggregate model was developed from A549 human lung epithelial cells by using a rotating-wall vessel bioreactor to study the interactions between Pseudomonas aeruginosa and lung epithelial cells. The suitability of the 3-D aggregates as an infection model was examined by immunohisto- chemistry, adherence and invasion assays, scanning electron microscopy, and cytokine and mucoglycoprotein production. Immunohistochemical characterization

  19. 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.

  20. Entry of diphtheria toxin linked to concanavalin A into primate and murine cells.

    PubMed

    Guillemot, J C; Sundan, A; Olsnes, S; Sandvig, K

    1985-02-01

    Diphtheria toxin linked by a disulfide bridge to concanavalin A was highly toxic to HeLa S3 and Vero cells, as well as to murine L cells. The cells could be protected with alpha-methyl mannoside, indicating that the conjugate binds mainly through its concanavalin A moiety. Treatment of Vero cells with phospholipase C, TPA (12-O-tetradecanoylphorbol-13-acetate), and vanadate, which strongly reduce the ability of the cells to bind free diphtheria toxin, had little protective effect against the conjugate, whereas SITS (L-acetamido-4'-isothiocyano-stilbene-2,2'disulfonic acid), which inhibits diphtheria toxin binding, as well as the subsequent entry, protected Vero cells, but not L cells. Both types of cells are protected against the conjugate by NH4Cl and monensin, indicating that an acidified compartment is necessary for entry into the cytosol. Exposure of cells, bound with surface conjugate, to low pH induced entry of the toxin into Vero cells, but not into L Cells. Phospholipase C, TPA, and vanadate did not protect L cells against the conjugate. It is concluded that toxin in the conjugate enters L cells by a route which involves low pH, but which is not identical to that in Vero cells. PMID:3844014

  1. Thin, high quality GaInP compositionally graded buffer layers grown at high growth rates for metamorphic III-V solar cell applications

    NASA Astrophysics Data System (ADS)

    Garcia, I.; France, R. M.; Geisz, J. F.; Simon, J.

    2014-05-01

    The metamorphic growth of lattice-mismatched materials has allowed optimizing the bandgap combination in multijunction solar cells for the solar spectrum under consideration. Buffer structures are used to accommodate the lattice-mismatch by introducing dislocations and relaxing the material in a controlled way. However, the metamorphic buffers typically involve significant growth time and material usage, which increases the cost of these solar cells. In this work, the thinning of buffer structures with continuously, linearly graded misfit is addressed with the goal of increasing the cost-effectiveness of metamorphic multijunction solar cells. The relaxation dynamics and quality of the buffer layers analyzed were assessed by in-situ stress measurements and ex-situ measurements of residual strain, threading dislocation density and surface roughness. Their ultimate quality has been tested using these buffers as templates for the growth of 1 eV Ga0.73In0.27As solar cells. The deleterious effect of thinning the grade layer of these buffer structures from 2 to 1 ?m was investigated. It is shown that prompting the relaxation of the buffer by using a stepwise misfit jump at the beginning of the grade layer improves the quality of the thinned buffer structure. The residual threading dislocation density of the optimized thin buffers, grown at a high growth rate of 7 ?m/h, is 3×106 cm-2, and solar cells on these buffers exhibit near-ideal carrier collection efficiency and a Voc of 0.62 V at 1-sun direct terrestrial spectrum.

  2. 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.

  3. The polyGeVero® software for fast and easy computation of 3D radiotherapy dosimetry data

    NASA Astrophysics Data System (ADS)

    Kozicki, Marek; Maras, Piotr

    2015-01-01

    The polyGeVero® software package was elaborated for calculations of 3D dosimetry data such as the polymer gel dosimetry. It comprises four workspaces designed for: i) calculating calibrations, ii) storing calibrations in a database, iii) calculating dose distribution 3D cubes, iv) comparing two datasets e.g. a measured one with a 3D dosimetry with a calculated one with the aid of a treatment planning system. To accomplish calculations the software was equipped with a number of tools such as the brachytherapy isotopes database, brachytherapy dose versus distance calculation based on the line approximation approach, automatic spatial alignment of two 3D dose cubes for comparison purposes, 3D gamma index, 3D gamma angle, 3D dose difference, Pearson's coefficient, histograms calculations, isodoses superimposition for two datasets, and profiles calculations in any desired direction. This communication is to briefly present the main functions of the software and report on the speed of calculations performed by polyGeVero®.

  4. Broad visible emission from GaN nanowires grown on n-Si (1 1 1) substrate by PVD for solar cell application

    NASA Astrophysics Data System (ADS)

    Saron, K. M. A.; Hashim, M. R.

    2013-04-01

    Nanostructured gallium nitrides (GaNs) were grown on a catalyst-free Si (1 1 1) substrates using physical vapor deposition via thermal evaporation of GaN powder at 1150 °C in the absence of NH3 gas for different deposition time. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometer (EDX) results indicated that the growth of GaN nanostructure varies with deposition time. Both X-ray diffraction (XRD) patterns and Raman spectra reveals a hexagonal GaN with wurtzite structure. Photoluminescence (PL) showed that the UV emission was suppressed, and the visible band emission was enhanced with increasing deposition time. Enhancement of visible band emission from the GaN NWs is due to the increasement of deep level states, which was resulted from growth process. Current-voltage (IV) characteristics of GaN/Si heterostructure were measured and good rectifying behavior was observed for this photodiode (PD). The forward current under illumination was almost three times than that in the dark current at +5 V. Responsivity of the photodetector was 10.5 A/W at range from 350 nm to 500 nm, which rapidly increased to 13.6 A/W at 700 nm. We found that the fabricated photodiode PD has an infra-red (IR) photoresponse behavior. The analysis of optical and electrical properties indications that the grown GaN in the absent of NH3 is a promising optical material and has potential applications in photo voltage solar cell.

  5. Solar cells. Electron-hole diffusion lengths > 175 ?m in solution-grown CH3NH3PbI3 single crystals.

    PubMed

    Dong, Qingfeng; Fang, Yanjun; Shao, Yuchuan; Mulligan, Padhraic; Qiu, Jie; Cao, Lei; Huang, Jinsong

    2015-02-27

    Long, balanced electron and hole diffusion lengths greater than 100 nanometers in the polycrystalline organolead trihalide compound CH3NH3PbI3 are critical for highly efficient perovskite solar cells. We found that the diffusion lengths in CH3NH3PbI3 single crystals grown by a solution-growth method can exceed 175 micrometers under 1 sun (100 mW cm(-2)) illumination and exceed 3 millimeters under weak light for both electrons and holes. The internal quantum efficiencies approach 100% in 3-millimeter-thick single-crystal perovskite solar cells under weak light. These long diffusion lengths result from greater carrier mobility, longer lifetime, and much smaller trap densities in the single crystals than in polycrystalline thin films. The long carrier diffusion lengths enabled the use of CH3NH3PbI3 in radiation sensing and energy harvesting through the gammavoltaic effect, with an efficiency of 3.9% measured with an intense cesium-137 source. PMID:25636799

  6. 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.

  7. Changes in phosphatidylinositol metabolism in response to hyperosmotic stress in Daucus carota L. cells grown in suspension culture

    Microsoft Academic Search

    Myeon H. Cho; Stephen B. Shears; Wendy F. BOSS

    1993-01-01

    Carrot (Daucus carota L.) cells plasmolyzed within 30 s after adding sorbitol to increase the osmotic strength of the medium from 0.2 to 0.4 or 0.6 osmolal. However, there was no significant change in the polyphosphorylated inositol phospholipids or inositol phosphates or in inositol phospholipid metabolism within 30 s of imposing the hyperosmotic stress. Maximum changes in phospha- tidylinositol 4-monophosphate

  8. Production of single cell protein through fermentation of a perennial grass grown on saline lands with Cellulomonas biazotea

    Microsoft Academic Search

    M. Ibrahim Rajoka

    2005-01-01

    Microbial protein from alkali-treated Leptochloa fusca (kaller grass) was produced by growing Cellulomonasbiazoteain shake flasks and in an aerated 6-l fermentor. Single cell protein, produced in the fermentor contained 56.10 ± 4.64, 60.00 ± 5.04, 11.50 ± 1.34, 12.95 ± 1.24, 3.50 ± 0.24 and 1.00 ± 0.44 true protein, crude protein, crude fibre, ash, cellulose and RNA content respectively.

  9. 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. PMID:25664570

  10. The role of connexins in the differentiation of NT2 cells in Sertoli-NT2 cell tissue constructs grown in the rotating wall bioreactor

    Microsoft Academic Search

    R. Shamekh; D. F. Cameron; A. E. Willing; S. Saporta

    2006-01-01

    Neural transplantation is developing as a successful treatment for neurodegenerative diseases such as Parkinson’s disease.\\u000a The human Ntera-2\\/D1 (NT2) cell line is an attractive alternative to the use of human fetal neurons as a cell source for transplantation.\\u000a We have explored combining NT2 cells, as a neuronal source, and Sertoli cells, which may act as a graft facilitator to enhance

  11. Simian immunodeficiency virus (SIV) gp130 oligomers protect rhesus macaques (Macaca mulatta) against the infection with SIVmac32H grown on T-cells or derived ex vivo.

    PubMed

    Luke, W; Coulibaly, C; Dittmer, U; Voss, G; Oesterle, R; Makoschey, B; Sauermann, U; Jurkiewicz, E; Stahl-Henning, C; Petry, H; Hunsmann, G

    1996-02-15

    The efficacy of three SIVmac32H gp130 vaccines was compared in rhesus monkeys. Three rhesus monkeys were each immunized over a period of 20 weeks with a total of 600 microgram virion-derived gp130 oligomers (O-gp130) mixed with keyhole limpet hemocyanin and emulsified with incomplete Freund's adjuvant. Three other monkeys were infected with 5 x 10(8) PFU of vaccinia virus wild type (VV-wt) while three additional animals received an equivalent dose of VV expressing the gp130 of SIVmac (VV-gp130). At Week 8, the two VV-wt animals received an additional immunization with 100 microgram O-gp130 each. All VV-infected animals then received booster immunizations at Weeks 12, 16, and 20 with a total of 300 microgram O-gp130 per animal. All animals along with two controls were challenged iv with 50 MID50 of T-cell-grown SIVmac32H at Week 22. Four weeks after the challenge and thereafter, both controls and one animal from either VV group were infected as demonstrated by polymerase chain reaction (PCR), virus isolation, and antibody response. In contrast, all O-gp130 animals and one animal each from the VV-wt and the VV-gp130 group were completely protected as shown by negative PCR and virus reisolation. One animal of the VV-gp130 group was partially protected, since it remained virus isolation negative but became PCR positive. All protected animals did not develop a secondary antibody response. Six months after the first challenge, the five completely protected animals were reimmunized twice 4 weeks apart with a total of 200 microgram O-gp130 per animal. Two weeks later, all animals were challenged with 5 MID50 of the SIVmac32H/spI prepared from the spleen of an immunized, but unprotected SIV-infected rhesus monkey. After the second challenge, all three control animals and one of the vaccinees become productively infected. In contrast, two animals were completely protected, one from the former O-gp130 and one from the former VV-gp130 group. One animal from the former VV-wt group was only DNA-PCR positive and thus partially protected. Therefore, immunization with virion-derived gp130 oligomers of SIVmac32H can confer protection against the infection with T-cell-grown SIVmac32H as well as the ex vivo isolate SIVmac32H/spI. PMID:8607276

  12. 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].

  13. InGaAs/GaAsP strain balanced multi-quantum wires grown on misoriented GaAs substrates for high efficiency solar cells

    SciTech Connect

    Alonso-Álvarez, D.; Thomas, T.; Führer, M.; Hylton, N. P.; Ekins-Daukes, N. J. [Department of Physics, Imperial College, London SW7 2BZ (United Kingdom); Lackner, D.; Philipps, S. P.; Bett, A. W. [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstrasse 2, 79110 Freiburg (Germany); Sodabanlu, H.; Fujii, H.; Watanabe, K.; Sugiyama, M. [Department of Electrical Engineering and Information Systems, The University of Tokyo, Tokyo (Japan); Nasi, L.; Campanini, M. [CNR-IMEM Sezione di Parma, Parco Area delle Scienze 37/A, 43010 Fontanini-Parma (Italy)

    2014-08-25

    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??s, 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.

  14. 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

  15. The role of connexins in the differentiation of NT2 cells in Sertoli-NT2 cell tissue constructs grown in the rotating wall bioreactor.

    PubMed

    Shamekh, R; Cameron, D F; Willing, A E; Saporta, S

    2006-04-01

    Neural transplantation is developing as a successful treatment for neurodegenerative diseases such as Parkinson's disease. The human Ntera-2/D1 (NT2) cell line is an attractive alternative to the use of human fetal neurons as a cell source for transplantation. We have explored combining NT2 cells, as a neuronal source, and Sertoli cells, which may act as a graft facilitator to enhance neuronal survival and differentiation, and ameliorate the host immune response, into a tissue construct for use in cell replacement therapy for neurodegenerative disease. This Sertoli-NT2-aggregated cell (SNAC) tissue construct is formed in the high aspect ratio vessel (HARV) bioreactor. NT2 cells differentiate to dopaminergic NT2N neurons within the SNAC tissue construct without retinoic acid. We report here that the gap junction protein connexin 43 is decreased among differentiated NT2N neurons. Inhibition of connexin 43 with 18beta glycyrrhetinic acid and carbenoxolone, a glycyrrhetinic acid derivative, during formation of the SNAC tissue constructs disrupts the differentiation of NT2 cells. Therefore, connexin 43 is important in the differentiation of NT2 cells in the SNAC tissue construct. PMID:16328273

  16. Facile fabrication of dye-sensitized solar cells utilizing carbon nanotubes grown over 2D hexagonal bimetallic ordered mesoporous materials

    NASA Astrophysics Data System (ADS)

    Balamurugan, J.; Thangamuthu, R.; Pandurangan, A.; Jayachandran, M.

    2013-03-01

    High-surface area and well-ordered mesoporous Fe incorporated SBA-15 (Fe-SBA-15), Fe-Cr incorporated SBA-15 (Fe-Cr-SBA-15) and Cr incorporated SBA-15 (Cr-SBA-15) catalysts are synthesized following a controlled post synthesis grafting process. The activities of all the catalysts are tested systematically and quantitatively towards the production of carbon nanotubes (CNTs) by chemical vapour deposition. In order to obtain CNTs with high quality and quantity, the parameters like temperature, reaction time and gas flow rate are optimized. Under optimum conditions, the Fe-Cr-SBA-15 catalyst is produced with high yield and uniform diameter of CNTs. The transmission electron microscopy result reveals high purity and well-graphitized structure of CNTs. The synthesized CNTs are used as counter electrode material for dye-sensitized solar cells (DSSCs). The CNTs based counter electrode shows good chemical stability, lower charge-transfer resistance and higher electrocatalytic activity towards I3-/I- redox reaction than that of platinum (Pt) counter electrode. The energy conversion efficiency of the CNTs counter electrode based DSSCs reaches 8.86% under irradiation with a simulated solar light intensity of 100 mW cm-2. The results prove that CNTs are one of the suitable candidates for Pt free counter electrode for DSSCs.

  17. Uptake of Cadmium by Rice Grown on Contaminated Soils and Its Bioavailability/Toxicity in Human Cell Lines (Caco-2/HL-7702).

    PubMed

    Aziz, Rukhsanda; Rafiq, Muhammad Tariq; Li, Tingqiang; Liu, Di; He, Zhenli; Stoffella, P J; Sun, Kewang; Xiaoe, Yang

    2015-04-01

    Cadmium (Cd) enters the food chain from polluted soils via contaminated cereals and vegetables; therefore, an understanding of Cd bioaccessibility, bioavailability, and toxicity in humans through rice grain is needed. This study assessed the Cd bioaccessibility, bioavailability, and toxicity to humans from rice grown on Cd-contaminated soils using an in vitro digestion method combined with a Caco-2/HL-7702 cell model. Cadmium bioaccessibility (18.45-30.41%) and bioavailability (4.04-8.62%) were found to be significantly higher in yellow soil (YS) rice than calcareous soil (CS) rice with the corresponding values of 6.89-11.43 and 1.77-2.25%, respectively. Toxicity assays showed an initial toxicity in YS rice at 6 mg kg(-1) Cd, whereas CS rice did not show any significant change due to low Cd concentrations. The acidic soils of Cd-contaminated areas can contribute to a higher dietary intake of Cd. Therefore, it is imperative to monitor Cd concentration in rice to minimize human health risk. PMID:25738308

  18. 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.

  19. Antioxidant Response to NaCl Stress in a Control and an NaCl-Tolerant Cotton Cell Line Grown in the Presence of Paraquat, Buthionine Sulfoximine, and Exogenous Glutathione.

    PubMed

    Gossett, D. R.; Banks, S. W.; Millhollon, E. P.; Lucas, M. C.

    1996-10-01

    A cotton (Gossypium hirsutum L.) control and NaCl-tolerant cell line (cv Coker 312) were grown on media with or without NaCl in the presence or absence of paraquat, buthionine sulfoximine, and oxidized glutathione. On medium with 150 mM NaCl the NaCl-tolerant cell line exhibited no reduction in growth, whereas a 96% reduction was observed in the control line. The NaCl-tolerant cell line that was grown on 150 mM NaCl exhibited significantly greater catalase (341%), peroxidase (319%), glutathione reductase (287%), ascorbate peroxidase (450%), [gamma]-glutamylcysteine synthetase (224%), and glutathione S-transferase (500%) activities than the intolerant control. The NaCl-tolerant cell line had a significantly lower dehydroascorbic acid/ascorbic acid ratio. Paraquat reduced growth by 20 and 53.7%, respectively, in the NaCl-tolerant and control cell line. The NaCl-tolerant cell line also showed a slight tolerance to buthionine sulfoximine. In the buthionine sulfoximine experiments reduced glutathione restored growth in both cell lines, whereas oxidized glutathione restored growth only in the NaCl-tolerant cell line. These data indicate that the NaCl-tolerant cell line exhibited a cross-tolerance to a variety of stress variables and had a more active ascorbate-glutathione cycle. PMID:12226422

  20. 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.

  1. Toxoplasma gondii grown in human cells uses GalNAc-containing glycosylphosphatidylinositol precursors to anchor surface antigens while the immunogenic Glc-GalNAc-containing precursors remain free at the parasite cell surface.

    PubMed

    Azzouz, Nahid; Shams-Eldin, Hosam; Niehus, Sebastian; Debierre-Grockiego, Françoise; Bieker, Ulrike; Schmidt, Jörg; Mercier, Corinne; Delauw, Marie-France; Dubremetz, Jean-François; Smith, Terry K; Schwarz, Ralph T

    2006-01-01

    Toxoplasma gondii is a ubiquitous parasite that infects nearly all warm-blooded animals. Developmental switching in T. gondii, from the virulent tachyzoite to the relatively quiescent bradyzoite stage, is responsible for the disease propagation after alteration of the immune status of the carrier. The redifferentiation event is characterized by an over expression of a tachyzoite specific set of glycosylphosphatidylinositol anchored surface antigens and free GPIs. T. gondii grown in animal cells uses two glycosylphosphatidylinositol precursors to anchor the parasite surface proteins. The first form has an N-acetylgalactosamine residue bound to a conserved three-mannosyl core glycan, while the second structure contains an additional terminal glucose linked to the N-acetylgalactosamine side branch. Sera from persons infected with T. gondii reacted only with the glucose-N-acetylgalactosamine-containing structure. Here we report that T. gondii cultured in human cells uses predominantly the N-acetylgalactosamine-containing structure to anchor the parasite surface antigens. On the other hand, glycosylphosphatidylinositol structures having an additional terminal glucose are found exclusively on the parasite cell surface as free glycolipids participating in the production of cytokines that are implicated in the pathogenesis of T. gondii. We also provide evidence that such free glycosylphosphatidylinositols are restricted mainly to the lipid microdomains in the parasite cell surface membrane and mostly associated with proteins involved in the parasite motility as well as invasion of the host cell. PMID:16822699

  2. Carrier dynamics in bulk 1eV InGaAsNSb materials and epitaxial lift off GaAs-InAlGaP layers grown by MOVPE for multi-junction solar cells

    NASA Astrophysics Data System (ADS)

    Sin, Yongkun; LaLumondiere, Stephen; Lotshaw, William; Moss, Steven C.; Kim, Tae Wan; Forghani, Kamran; Mawst, Luke J.; Kuech, Thomas F.; Tatavarti, Rao; Wibowo, Andree; Pan, Noren

    2013-03-01

    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 material that is currently under extensive investigation is bulk dilute nitride such as InGaAsN(Sb) lattice matched to GaAs substrates. Both approaches utilizing dilute nitrides and lattice-mismatched InGaAs layers have a potential to achieve high performance triple-junction solar cells. In addition, it will be beneficial for both commercial and space applications if III-V triple-junction solar cells can significantly reduce weight and can be manufactured cost effectively while maintaining high efficiency. The most 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 nitride layers lattice matched to GaAs substrates, where carrier lifetime measurements are crucial in optimizing MOVPE materials growth. We studied carrier dynamics in InGaAsN(Sb) layers with different amounts of N incorporated. Carrier lifetimes were also measured from InGaAsN(Sb) layers at different stages of post-growth thermal annealing steps. Post-growth annealing yielded significant improvements in carrier lifetimes of InGaAsNSb double hetero-structure (DH) samples compared to InGaAsN DH samples possibly due to the surfactant effect of Sb. In addition, we studied carrier dynamics in MOVPE-grown GaAs-InAl(Ga)P layers 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 layers had various doping densities and thicknesses. We present our TR-PL results from both pre- and post-ELO processed GaAs-InAl(Ga)P samples.

  3. High titer growth of human and avian influenza viruses in an immortalized chick embryo cell line without the need for exogenous proteases.

    PubMed

    Smith, Kristen A; Colvin, Christopher J; Weber, Patty S D; Spatz, Stephen J; Coussens, Paul M

    2008-07-01

    The current method of growing influenza virus for vaccine production is through the use of embryonated chicken eggs. This manufacturing system yields a low concentration of virus per egg, requires significant downstream production for purification, and demands a considerable amount of time for production. We have demonstrated an immortalized chick embryo cell line, termed PBS-1, is capable of growing unmodified recent isolates of human and avian influenza A and B viruses to extremely high titers. In many cases, PBS-1 cells out perform primary chick embryo kidney (CEK) cells, Madin-Darby Canine Kidney (MDCK) cells and African green monkey kidney cells (Vero) in growth of recent influenza isolates. PBS-1 cells are free of any exogenous agents, are non-tumorigenic, and are readily adaptable to a variety of culture conditions, including growth on microcarrier beads. Influenza viruses grown in PBS-1 cells are released into the culture fluid without the need for exogenous proteases, thus simplifying downstream processing. In addition to offering a significant improvement in vaccine production, PBS-1 cells should prove valuable in diagnostics and as a cell line of choice for influenza virus research. PMID:18524432

  4. 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.

  5. Investigation of H2/CH4 mixed gas plasma post-etching process for ZnO:B front contacts grown by LP-MOCVD method in silicon-based thin-film solar cells

    NASA Astrophysics Data System (ADS)

    Wang, Li; Zhang, Xiaodan; Zhao, Ying; Yamada, Takuto; Naito, Yusuke

    2014-10-01

    A new plasma post-etching method, H2/CH4 mixed gas plasma, is introduced to modify ZnO:B films grown by LP-MOCVD technique, successfully relaxing the double trade-offs, i.e., transparency/conductivity trade-off and surface texture/Voc and FF trade-off. To deeply evaluate the post-etching process, optical emission spectroscopy technique is applied to diagnose the plasma condition. Upon different etching power, three distinct possible etching mechanisms are identified by analyzing the evolution of H?*, H?*, CH* emission species in the plasma space. It is demonstrated that H?* and CH* species are responsible for the physical etching process and chemical etching process, respectively, from which a new “soft” surface morphology is formed with a combination of micro- and nano-sized texture. Additionally, H?* species can bond with ZnO and also passivate the grains boundaries, thereby making both the carrier concentration and hall mobility increase. This process is defined as chemical bonding process. Finally, pin-type a-Si:H single-junction solar cells with an optimized device structure is grown on the etched ZnO:B substrate. The corresponding electrical parameters, such as Jsc, Voc and FF, are simultaneously improved compared with the solar cell deposited on as-grown ZnO:B substrate with the same fabrication process. As a consequence, a noteworthy 8.85% conversion-efficiency is achieved with an absorber layer thickness only 160 nm.

  6. Molecular Biology of the Cell Vol. 21, 38383852, November 15, 2010

    E-print Network

    Boyer, Edmond

    Molecular Biology of the Cell Vol. 21, 3838­3852, November 15, 2010 The SARS Coronavirus E Protein in mammalian cells and further demonstrate that the last four carboxy-terminal amino acids of E form a novel E accumulates, in SARS-CoV­infected Vero E6 cells. Ectopic expression of E in MDCKII epithelial

  7. The anti-canine distemper virus activities of ex vivo-expanded canine natural killer cells.

    PubMed

    Park, Ji-Yun; Shin, Dong-Jun; Lee, Soo-Hyeon; Lee, Je-Jung; Suh, Guk-Hyun; Cho, Duck; Kim, Sang-Ki

    2015-04-17

    Natural killer (NK) cells play critical roles in induction of antiviral effects against various viruses of humans and animals. However, few data on NK cell activities during canine distemper virus (CDV) infections are available. Recently, we established a culture system allowing activation and expansion of canine non-B, non-T, large granular NK lymphocytes from PBMCs of normal dogs. In the present study, we explored the ability of such expanded NK cells to inhibit CDV infection in vitro. Cultured CD3(-)CD5(-)CD21(-) NK cells produced large amounts of IFN-?, exhibited highly upregulated expression of mRNAs encoding NK-cell-associated receptors, and demonstrated strong natural killing activity against canine tumor cells. Although the expanded NK cells were dose-dependently cytotoxic to both normal and CDV-infected Vero cells, CDV infection rendered Vero cells more susceptible to NK cells. Pretreatment with anti-CDV serum from hyperimmunized dogs enhanced the antibody-dependent cellular cytotoxicity (ADCC) of NK cells against CDV-infected Vero cells. The culture supernatants of NK cells, added before or after infection, dose-dependently inhibited both CDV replication and development of CDV-induced cytopathic effects (CPEs) in Vero cells. Anti-IFN-? antibody neutralized the inhibitory effects of NK cell culture supernatants on CDV replication and CPE induction in Vero cells. Such results emphasize the potential significance of NK cells in controlling CDV infection, and indicate that NK cells may play roles both during CDV infection and in combating such infections, under certain conditions. PMID:25680810

  8. Porcine aminopeptidase N mediated polarized infection by porcine epidemic diarrhea virus in target cells.

    PubMed

    Cong, Yingying; Li, Xiaoxue; Bai, Yunyun; Lv, Xiaonan; Herrler, Georg; Enjuanes, Luis; Zhou, Xingdong; Qu, Bo; Meng, Fandan; Cong, Chengcheng; Ren, Xiaofeng; Li, Guangxing

    2015-04-01

    Infection of polarized intestinal epithelial cells by porcine epidemic diarrhea virus (PEDV) was characterized. Indirect immunofluorescence assay, real-time PCR, and transmission electron microscopy confirmed PEDV can be successfully propagated in immortalized swine small intestine epithelial cells (IECs). Infection involved porcine aminpeptidase N (pAPN), a reported cellular receptor for PEDV, transient expression of pAPN and siRNA targeted pAPN increased and decreased the infectivity of PEDV in IECs, respectively. Subsequently, polarized entry into and release from both Vero E6 and IECs was analyzed. PEDV entry into polarized cells and pAPN grown on membrane inserts occurs via apical membrane. The progeny virus released into the medium was also quantified which demonstrated that PEDV is preferentially released from the apical membrane. Collectively, our data demonstrate that pAPN, the cellular receptor for PEDV, mediates polarized PEDV infection. These results imply the possibility that PEDV infection may proceed by lateral spread of virus in intestinal epithelial cells. PMID:25681796

  9. Characterization of the 3a Protein of SARS-associated Coronavirus in Infected Vero E6 Cells and SARS Patients

    E-print Network

    Tian, Weidong

    1 , Xiao-Sheng Jiang1 , Lv Shi1 , Hu Zhou1 Lei Zhang1 , Xiao-Dong Wu2 , Ying Lin2 , Yong-Yong Ji2 , Lei Xiong2 Yan Jin2 , Er-Hei Dai4 , Xiao-Yi Wang4 , Bin-Ying Si4 , Jin Wang4 Hong-Xia Wang4 , Cui and SARS Patients Rong Zeng1 *, Rui-Fu Yang4 , Mu-De Shi2 , Man-Rong Jiang2 You-Hua Xie3 , Hong-Qiang Ruan

  10. Non-linear relationships between aflatoxin B1 levels and the biological response of monkey kidney vero cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin (AF)-producing fungi contaminate food and feed during preharvest, storage and processing periods. Once consumed, AF accumulates in tissues, causing illnesses in animals and humans. At least 20 different types of AFs have been identified, and of these, aflatoxin B1 (AFB1) is the most ubiqui...

  11. Virological and Serological Findings in Rousettus aegyptiacus Experimentally Inoculated with Vero Cells-Adapted Hogan Strain of Marburg Virus

    PubMed Central

    Paweska, Janusz T.; Jansen van Vuren, Petrus; Masumu, Justin; Leman, Patricia A.; Grobbelaar, Antoinette A.; Birkhead, Monica; Clift, Sarah; Swanepoel, Robert; Kemp, Alan

    2012-01-01

    The Egyptian fruit bat, Rousettus aegyptiacus, is currently regarded as a potential reservoir host for Marburg virus (MARV). However, the modes of transmission, the level of viral replication, tissue tropism and viral shedding pattern remains to be described. Captive-bred R. aegyptiacus, including adult males, females and pups were exposed to MARV by different inoculation routes. Blood, tissues, feces and urine from 9 bats inoculated by combination of nasal and oral routes were all negative for the virus and ELISA IgG antibody could not be demonstrated for up to 21 days post inoculation (p.i.). In 21 bats inoculated by a combination of intraperitoneal/subcutaneous route, viremia and the presence of MARV in different tissues was detected on days 2–9 p.i., and IgG antibody on days 9–21 p.i. In 3 bats inoculated subcutaneously, viremia was detected on days 5 and 8 (termination of experiment), with virus isolation from different organs. MARV could not be detected in urine, feces or oral swabs in any of the 3 experimental groups. However, it was detected in tissues which might contribute to horizontal or vertical transmission, e.g. lung, intestines, kidney, bladder, salivary glands, and female reproductive tract. Viremia lasting at least 5 days could also facilitate MARV mechanical transmission by blood sucking arthropods and infections of susceptible vertebrate hosts by direct contact with infected blood. All bats were clinically normal and no gross pathology was identified on post mortem examination. This work confirms the susceptibility of R. aegyptiacus to infection with MARV irrespective of sex and age and contributes to establishing a bat-filovirus experimental model. Further studies are required to uncover the mode of MARV transmission, and to investigate the putative role of R. aegyptiacus as a reservoir host. PMID:23029039

  12. Impact of growth temperature and substrate orientation on dilute-nitride-antimonide materials grown by MOVPE for multi-junction solar cell application

    NASA Astrophysics Data System (ADS)

    Kim, T. W.; Kuech, T. F.; Mawst, L. J.

    2014-11-01

    Nitrogen incorporation in bulk films of GaAsN, InGaAsN, and GaAsSbN films grown by metalorganic vapor phase epitaxy (MOVPE) on (100) and (311)B GaAs substrates was investigated. These films, nominally lattice-matched to a GaAs substrate, were deposited at relatively higher growth temperature (600 °C) than typically used for MOVPE-grown dilute-nitride materials (~500-530 °C), in order to reduce the background carbon impurity concentration. Even at these higher growth temperatures, sufficient N incorporation is achieved for targeting Eg~1 eV InGaAsN and GaAsN with low background carrier concentration (1-2×1017 cm-3). The presence of Sb is found to significantly inhibit N incorporation, making it challenging to achieve films of GaAsSbN grown at 600 °C with a sufficient N concentration to achieve a 1 eV band gap energy. For GaAsN and InGaAsN on (311)B GaAs substrates, increased N incorporation with lower background carbon concentration is observed, relative to films on (100) GaAs. By contrast, GaAsSbN on (311)B GaAs substrate exhibit lower-N incorporation relative to films on (100) GaAs, presumably due to surface site competition between Sb and N. The background hole carrier concentrations of thermally annealed InGaAsN and GaAsSbN on (311)B are about a factor of two lower than those on (100) GaAs substrate.

  13. Bi2S3microspheres grown on graphene sheets as low-cost counter-electrode materials for dye-sensitized solar cells.

    PubMed

    Li, Guang; Chen, Xiaoshuang; Gao, Guandao

    2014-03-21

    In this work, we synthesized 3D Bi2S3 microspheres comprised of nanorods grown along the (211) facet on graphene sheets by a solvothermal route, and investigated its catalytic activities through I-V curves and conversion efficiency tests as the CE in DSSCs. Although the (211) facet has a large band gap for a Bi2S3 semiconductor, owing to the introduction of graphene into the system, its short-circuit current density, open-circuit voltage, fill factor, and efficiency were Jsc = 12.2 mA cm(-2), Voc = 0.75 V, FF = 0.60, and ? = 5.5%, respectively. By integrating it with graphene sheets, our material achieved the conversion efficiency of 5.5%, which is almost triple the best conversion efficiency value of the DSSCs with (211)-faceted 3D Bi2S3 without graphene (1.9%) reported in the latest literature. Since this conversion-efficient 3D material grown on the graphene sheets significantly improves its catalytic properties, it paves the way for designing and applying low-cost Pt-free CE materials in DSSC from inorganic nanostructures. PMID:24509629

  14. Characterization of peroxisomes in glucose-grown Hansenula polymorpha and their development after the transfer of cells into methanol-containing media

    Microsoft Academic Search

    M. Veenhuis; I. Keizer; W. Harder

    1979-01-01

    Cells of Hansenula polymorpha growing exponentially on glucose generally contained a single peroxisome of small dimension, irregular in shape and located in close proximity to the cell wall. Crystalline inclusions in the peroxisomal matrix were not observed. Associations of the organelles with one or more strands of endoplasmic reticulum were evident. In stationary phase cells the size of the peroxisomes

  15. Studies on the Production of Digitalis Cardenolides by Plant Tissue Culture: II. EFFECT OF LIGHT AND PLANT GROWTH SUBSTANCES ON DIGITOXIN FORMATION BY UNDIFFERENTIATED CELLS AND SHOOT-FORMING CULTURES OF DIGITALIS PURPUREA L. GROWN IN LIQUID MEDIA.

    PubMed

    Hagimori, M; Matsumoto, T; Obi, Y

    1982-03-01

    Undifferentiated, highly chlorophyllous cell cultures; undifferentiated white cell cultures; green, shoot-forming cultures; and white, shoot-forming cultures of Digitalis purpurea L. were established and subcultured every 3 weeks in liquid media in the light or in the dark. The digitoxin content, the chlorophyll content, and the ribulose bisphosphate carboxylase activity of these cultures were assayed. The light-grown, green, shoot-forming cultures accumulated considerable amounts of digitoxin (about 20 to 40 micrograms per gram dry weight), and the white, shoot-forming cultures without chloroplasts accumulated about one-third that amount of digitoxin. The chlorophyll content and the ribulose bisphosphate carboxylase activity of the undifferentiated green cells were about the same as they were in the green, shoot-forming cultures, but the digitoxin content of the former was extremely low (about 0.05 to 0.2 microgram per gram dry weight), which is about the same as that in undifferentiated white cells without chloroplasts. Thus, it was concluded that the chloroplasts are not essential for the synthesis of digitoxin in Digitalis cells. The optimum concentrations of the tested compounds for accumulation of digitoxin were: benzyladenine, 0.01 to 1 milligram per liter; indoleacetic acid, 0.1 to 1 milligram per liter; alpha-naphthaleneacetic acid; 0.1 milligram per liter; and 2,4-dichlorophenoxyacetic acid, 0.01 milligram per liter. PMID:16662267

  16. 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…

  17. Changes in the two-dimensional proteome of the soluble fraction of nuclear proteins from Lepidium sativum root meristematic cells grown under clinorotation.

    PubMed

    Sobol, M A; González-Camacho, F; Kordyum, E L; Medina, F J

    2007-07-01

    The changes in the fundamental biological processes of nuclear RNA transcription and splicing under altered gravity conditions are still unclear. The quantitative and qualitative characteristics of the proteins involved in nuclear RNA metabolism in control and under clinorotation were investigated by two-dimensional gel electrophoresis. We revealed firstly a decrease in the isoelectric point range of nuclear soluble proteins, which are known to be actively engaged in nuclear RNA metabolism, and a shortening in the molecular weight range of them under clinorotation. Moreover, minor and major proteins in clinorotated samples had decreased optical densities in comparison with control ones. Our results are in agreement with the hypothesis that a rearrangement of the pattern of nuclear proteins involved in gene expression processes occurs in seedlings grown and developed in altered gravity. PMID:18372723

  18. Vero cytotoxin-producing Escherichia coli, particularly serogroup O157, associated with human infections in England and Wales: 1992-4.

    PubMed Central

    Thomas, A.; Cheasty, T.; Frost, J. A.; Chart, H.; Smith, H. R.; Rowe, B.

    1996-01-01

    Investigations were performed by the Laboratory of Enteric Pathogens on Vero cytotoxin-producing Escherichia coli (VTEC) in England and Wales from 1992-4. Bacterial isolates, faeces and sera obtained from patients with diarrhoea, bloody diarrhoea and haemolytic uraemic syndrome were examined. Using serotyping, Vero cytotoxin gene probing and serodiagnostic tests for E. coli O157, evidence of infection was detected in 543, 434 and 491 individuals in 1992, 1993 and 1994 respectively; VTEC of serogroup O157 were isolated from 470, 385 and 411 cases. The O157 VTEC strains belonged to at least 19 different phage types (PT) although 84% belonged to PT2, PT49, PT8, PT1 or PT4. Antibodies to E. coli O157 lipopolysaccharide were detected in 13% of the cases. The average annual rate of infection with O157 VTEC was 0.83/100000 and 12% of the 1458 individuals with evidence of infection with VTEC or E. coli O157 developed haemolytic uraemic syndrome. There were at least 18 general outbreaks and many family outbreaks. PMID:8760944

  19. Cyclic AMP stimulation of transferrin secretion by breast cancer cell grown on extracellular matrix or in two-compartment culture chambers

    SciTech Connect

    Vandewalle, B.; Hornez, L.; Revillion, F.; Lefebvre, J. (Lab. d'Endocrinologie Experimentale, Centre Oscar Lambret, Lille (France))

    1991-06-28

    Extrahepatic synthesis and secretion of transferrin (Tf), the major iron-carrying protein, have been described in normal and tumoral tissues suggesting a potential role for paracrine or autocrine function. In breast tumor cell MCF-7, we have previously shown a Tf secretion stimulated by estradiol which might confer selective growth advantages of these rapidly proliferating cells. The present work refers to possible additional Tf functions related to differentiation of breast tumor cells. We induced MCF-7 cell differentiation by the cyclic AMP derivative, dibutyryl cAMP (dB cAMP) and studied Tf secretion in different culture conditions after labeling with (35S) methionine. Our results demonstrate that dB cAMP stimulates Tf secretion only in culture environment that permits access to the basolateral surface and caters to the polarity requirements of the cell. These results suggest that Tf may also act as a modulator of cellular differentiation in breast cancer cells.

  20. RICKETTSIAL PHOSPHOLIPASE A 2 AS A PATHOGENIC MECHANISM IN A MODEL OF CELL INJURY BY TYPHUS AND SPOTTED FEVER GROUP RICKETTSIAE

    Microsoft Academic Search

    DAVID H. WALKER; HUI-MIN FENG; VSEVOLOD L. POPOV

    2001-01-01

    Phospholipase A2 activity by typhus group rickettsiae causes hemolysis in vitro. Rickettsial phospholi- pase A2 has been proposed to mediate entry into the host cell, escape from the phagosome, and cause injury to host cells by both typhus and spotted fever group rickettsiae. In a rickettsial contact-associated cytotoxicity model, the interaction of Rickettsia prowazekii or R. conorii with Vero cells

  1. Differences in Chlamydia trachomatis serovar E growth rate in polarized endometrial and endocervical epithelial cells grown in three-dimensional culture.

    PubMed

    Guseva, Natalia V; Dessus-Babus, Sophie; Moore, Cheryl G; Whittimore, Judy D; Wyrick, Priscilla B

    2007-02-01

    In vitro studies of obligate intracellular chlamydia biology and pathogenesis are highly dependent on the use of experimental models and growth conditions that mimic the mucosal architecture and environment these pathogens encounter during natural infections. In this study, the growth of Chlamydia trachomatis genital serovar E was monitored in mouse fibroblast McCoy cells and compared to more relevant host human epithelial endometrium-derived HEC-1B and cervix-derived HeLa cells, seeded and polarized on collagen-coated microcarrier beads, using a three-dimensional culture system. Microscopy analysis of these cell lines prior to infection revealed morphological differences reminiscent of their in vivo architecture. Upon infection, early chlamydial inclusion distribution was uniform in McCoy cells but patchy in both epithelial cell lines. Although no difference in chlamydial attachment to or entry into the two genital epithelial cell lines was noted, active bacterial genome replication and transcription, as well as initial transformation of elementary bodies to reticulate bodies, were detected earlier in HEC-1B than in HeLa cells, suggesting a faster growth, which led to higher progeny counts and titers in HEC-1B cells upon completion of the developmental cycle. Chlamydial development in the less relevant McCoy cells was very similar to that in HeLa cells, although higher progeny counts were obtained. In conclusion, this three-dimensional bead culture system represents an improved model for harvesting large quantities of infectious chlamydia progeny from their more natural polarized epithelial host cells. PMID:17088348

  2. 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. PMID:25659015

  3. Antigenic properties and diagnostic potential of puumala virus nucleocapsid protein expressed in insect cells.

    PubMed Central

    Vapalahti, O; Lundkvist, A; Kallio-Kokko, H; Paukku, K; Julkunen, I; Lankinen, H; Vaheri, A

    1996-01-01

    Puumala virus (PUU) is a member of the genus Hantavirus in the family Bunyaviridae and the causative agent of nephropathia epidemica, a European form of hemorrhagic fever with renal syndrome. Sera of nephropathia epidemica patients react specifically with PUU nucleocapsid (N) protein. In order to safely provide large quantities of antigen for diagnostic purposes, PUU Sotkamo strain N protein was expressed by using the baculovirus system in Sf9 insect cells to up to 30 to 50% of the total cellular protein. The recombinant N protein (bac-PUU-N) was solubilized with 6 M urea, dialyzed, and purified by anion-exchange liquid chromatography. In an immunoglobulin M mu-capture assay purified and unpurified bac-PUU-N antigen showed identical results compared with the results of a similar assay based on native PUU antigen grown in Vero E6 cells. An immunoglobulin G monoclonal antibody-capture assay based on unpurified bac-PUU-N also showed results identical to those of an assay with native PUU-N antigen. Moreover, a panel of monoclonal antibodies reactive with eight different epitopes showed identical reactivity patterns with both natural and bac-PUU-N antigen, while two epitopes in PUU-N expressed as a fusion protein in Escherichia coli were not recognized. Puumala hantavirus N protein expressed by the baculovirus system offers a safe and inexpensive source of specific antigen for large-scale diagnostic and seroepidemiological purposes. PMID:8748286

  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. PMID:12573000

  5. High Efficiency GaAs/Si Monolithic Three-Terminal Cascade Solar Cells Grown by Metal-Organic Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Yang, Mingju; Soga, Tetsuo; Egawa, Takashi; Jimbo, Takashi; Umeno, Masayoshi

    1994-05-01

    A high-efficiency GaAs/Si monolithic three-terminal cascade solar cell is proposed and fabricated by the metal-organic chemical vapor deposition (MOCVD) method and thermal diffusion method. The quantum efficiency in the long wavelength region was improved by using p-Si substrates with the resistivity of 10 ? ·cm as the Si bottom cells. Adopting a graded band-gap layer (GBL) of Al xGa1- xAs, the collection efficiency of the GaAs top cell was increased considerably. A total conversion efficiency of 19.1% was achieved at the AM0 condition for the GaAs/Si three-terminal cascade solar cell.

  6. Human Umbilical Cord Wharton’s Jelly Stem Cells Undergo Enhanced Chondrogenic Differentiation when Grown on Nanofibrous Scaffolds and in a Sequential Two-stage Culture Medium Environment

    Microsoft Academic Search

    Chui-Yee Fong; Arjunan Subramanian; Kalamegam Gauthaman; Jayarama Venugopal; Arijit Biswas; Seeram Ramakrishna; Ariff Bongso

    The current treatments used for osteoarthritis from cartilage damage have their disadvantages of donor site morbidity, complicated\\u000a surgical interventions and risks of infection and graft rejection. Recent advances in tissue engineering have offered much\\u000a promise in cartilage repair but the best cell source and in vitro system have not as yet been optimised. Human bone marrow\\u000a mesenchymal stem cells (hBMSCs)

  7. Studies on the respiratory system of aerobically (Dark) and anaerobically (Light) grown Rhodospirillum rubrum

    Microsoft Academic Search

    A. Thore; D. L. Keister; A. San Pietro

    1969-01-01

    1.A major part of the respiratory activity of light grown cells of Rhodospirillum rubrum is associated with a system identical with that found in dark grown cells.2.The specific activity of NADH and succinate dehydrogenase and cytochrome c reductase on a protein basis is the same in the particulate fraction from photosynthetic and aerobic cells. In contrast, the NADH and succinate

  8. Developmental transitions of Coxiella burnetii grown in axenic media

    PubMed Central

    Sandoz, Kelsi M.; Sturdevant, Daniel E.; Hansen, Bryan; Heinzen, Robert A.

    2014-01-01

    Coxiella burnetii undergoes a biphasic developmental cycle within its host cell that generates morphologically and physiologically distinct large cell variants (LCV) and small cell variants (SCV). During the lag phase of the C. burnetii growth cycle, non-replicating SCV differentiate into replicating LCV that in turn differentiate back into SCV during stationary phase. Nearly homogeneous SCV are observed in infected Vero cells after extended incubation (21 to 28 days). In the current study, we sought to establish whether C. burnetii developmental transitions in host cells are recapitulated during host cell-free (axenic) growth in first and second generation acidified citrate cysteine media (ACCM-1 and ACCM-2, respectively). We show that ACCM-2 supported developmental transitions and viability. Although ACCM-1 also supported SCV to LCV transition, LCV to SCV transition did not occur after extended incubation (21 days). Instead, C. burnetii exhibited a ghost-like appearance with bacteria containing condensed chromatin but otherwise devoid of cytoplasmic content. This phenotype correlated with a near total loss in viability between 14 and 21 days of cultivation. Transcriptional profiling of C. burnetii following 14 days of incubation revealed elevated expression of oxidative stress genes in ACCM-1 cultivated bacteria. ACCM-2 differs from ACCM-1 by the substitution of methyl-?-cyclodextrin (M?-CD) for fetal bovine serum. Addition of M?-CD to ACCM-1 at 7 days post-inoculation rescued C. burnetii viability and lowered expression of oxidative stress genes. Thus, M?-CD appears to alleviate oxidative stress in ACCM-2 to result in C. burnetii developmental transitions and viability that mimic host cell-cultivated organisms. Axenic cultivation of C. burnetii in ACCM-2 and new methods of genetic manipulation now allow investigation of the molecular basis of C. burnetii biphasic development. PMID:24286928

  9. Analysis of thymic stromal cell subpopulations grown in vitro on extracellular matrix in defined medium. IV. Cytokines secreted by human thymic epithelial cells in culture and their activities on murine thymocytes and bone marrow cells.

    PubMed Central

    Meilin, A; Shoham, J; Sharabi, Y

    1992-01-01

    In previous reports we described our approach to the cultivation of murine and human thymic epithelial cells in primary cultures, using defined, serum-free growth factor-supplemented medium and extracellular matrix-coated culture plates. The cells in these cultures displayed high metabolic activity and their supernatant was highly active on thymocytes. In the study reported here we analysed cytokine activities in the supernatant of human thymic epithelial cell cultures (HTES), by using the respective cytokine-dependent cell lines and by neutralization with specific monoclonal antibodies. Three cytokine activities were detected--interleukin-6 (IL-6), granulocyte colony-stimulating factor (G-CSF) and macrophage (M)-CSF. Other cytokine activities tested for [IL-1, IL-2, IL-7, interferon (IFN) and tumour necrosis factor (TNF)] were negative. The effect of HTES on concanavalin A (Con A)-induced proliferation of murine thymocytes could be completely abolished by anti-IL-6 antibodies, but not by antibodies to CSF, whereas enhancement of bone marrow cell proliferation by HTES was partially inhibited by either anti-G-CSF or anti-M-CSF antibodies and completely inhibited by both antibodies, but not at all by anti-IL-6. We can thus distinguish between thymocyte-related cytokines (IL-6) and bone marrow (myeloid/monocyte) related ones (G-CSF, M-CSF) in HTES. PMID:1385312

  10. 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.

  11. Deuterium isotope effects on the central carbon metabolism of Escherichia coli cells grown on a D2O-containing minimal medium.

    PubMed

    Hochuli, M; Szyperski, T; Wüthrich, K

    2000-05-01

    Isotope effects on the central carbon metabolism due to the addition of variable amounts of D2O (0 to 70%) were investigated with biosynthetically directed fractional 13C-labeling for Escherichia coli BL21(DE3) cells during exponential growth on a M9 minimal medium containing a mixture of 70% unlabeled and 30% uniformly 13C-labeled glucose as the sole carbon source. The resulting 13C-labeling patterns in the amino acids were analysed by two-dimensional [13C,1H]-correlation spectroscopy. With the aforementioned growth conditions, higher D2O contents resulted in an increase of the anaplerotic supply of the tricarboxylic acid cycle via carboxylation of phosphoenolpyruvate when compared to the influx of acetyl-CoA. Furthermore, the addition of D2O affected the C1 metabolic pathways that involve Ser and Gly. Otherwise the E. coli cells showed identical topologies of the active biosynthetic pathways in H2O and at elevated D2O contents, and the metabolic flux ratios characterizing glycolysis and the pentose phosphate pathway were not measurably affected by the addition of D2O. Cells that had been adapted for growth in D2O exhibited the same response to the presence of D2O in the nutrient medium as non-adapted cells. Implications of these data for the preparation of recombinant deuterated proteins for NMR studies are discussed. PMID:10909864

  12. Freestanding aligned carbon nanotube array grown on a large-area single-layered graphene sheet for efficient dye-sensitized solar cell.

    PubMed

    Qiu, Longbin; Wu, Qiong; Yang, Zhibin; Sun, Xuemei; Zhang, Yuanbo; Peng, Huisheng

    2015-03-01

    A novel carbon nanomaterial with aligned carbon nanotubes (CNTs) chemically bonded to a single-layered, large area graphene sheet is designed and fabricated, showing remarkable electronic and electrocatalytic properties. When the carbon nanomaterial is used as a counter electrode, the resulting dye-sensitized solar cell exhibits ?11% enhancement of energy conversion efficiency than aligned CNT array. PMID:24889384

  13. Feasibility evaluation of a new irradiation technique: three-dimensional unicursal irradiation with the Vero4DRT (MHI-TM2000)

    PubMed Central

    Mizowaki, Takashi; Takayama, Kenji; Nagano, Kazuo; Miyabe, Yuki; Matsuo, Yukinori; Kaneko, Shuji; Kokubo, Masaki; Hiraoka, Masahiro

    2013-01-01

    The Vero4DRT (MHI-TM2000) is a newly designed unique image-guided radiotherapy system consisting of an O-ring gantry. This system can realize a new irradiation technique in which both the gantry head and O-ring continuously and simultaneously rotate around the inner circumference of the O-ring and the vertical axis of the O-ring, respectively, during irradiation. This technique creates three-dimensional (3D) rotational dynamic conformal arc irradiation, which we term ‘3D unicursal irradiation’. The aim of this study was to present the concept and to estimate feasibility and potential advantages of the new irradiation technique. Collision maps were developed for the technique and a 3D unicursal plan was experimentally created in reference to the collision map for a pancreatic cancer case. Thereafter, dosimetric comparisons among the 3D unicursal, a two-dimensionally rotational dynamic conformal arc irradiation (2D–DCART), and an intensity-modulated radiation therapy (IMRT) plan were conducted. Dose volume data of the 3D unicursal plan were comparable or improved compared to those of the 2D–DCART and IMRT plans with respect to both the target and the organs at risk. The expected monitor unit (MU) number for the 3D unicursal plan was only 7% higher and 22.1% lower than the MUs for the 2D–DCART plan and IMRT plan, respectively. It is expected that the 3D unicursal irradiation technique has potential advantages in both treatment time and dose distribution, which should be validated under various conditions with a future version of the Vero4DRT fully implemented the function. PMID:22923744

  14. Pachytene spermatocyte protein(s) stimulate sertoli cells grown in bicameral chambers: Dose-dependent secretion of ceruloplasmin, sulfated glycoprotein-1, sulfated glycoprotein-2, and transferrin

    Microsoft Academic Search

    Makoto Onoda; Daniel Djakiew

    1991-01-01

    Summary  Interactions between pachytene spermatocytes and Sertoli cells were investigated using the bicameral culture chamber system.\\u000a Pachytene spermatocytes were isolated from adult rats with a purity in excess of 90% by centrifugal elutriation. The pachytene\\u000a spermatocytes were cultured in a defined media and pachytene spermatocyte protein prepared from the conditioned media by dialysis\\u000a and lyophilization. This pachytene spermatocyte protein was reconstituted

  15. 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

    2015-01-01

    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??m 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. PMID:25724221

  16. Herpesvirus simiae (B virus): Replication of the virus and identification of viral polypeptides in infected cells

    Microsoft Academic Search

    J. K. Hilliard; R. Eberle; S. L. Lipper; R. M. Munoz; S. A. Weiss

    1987-01-01

    Summary The events and products of replication ofHerpesvirus simiae (B virus) in Vero cells were studied. The time course of the synthetic events of DNA replication and protein synthesis were found to be similar to the processes of the herpes simplex viruses and SA 8. Infectious progeny virus were detected by 4 hours post infection and were first found extracellularly

  17. Phyllosphere of Organically Grown Strawberries

    E-print Network

    , Alnarp Print: SLU Service/Repro, Alnarp 2013 #12;Phyllosphere of Organically Grown StrawberriesPhyllosphere of Organically Grown Strawberries Interactions between the Resident Microbiota (print version) 978-91-576-7908-6 ISBN (electronic version) 978-91-576-7909-3 © 2013 Justine Sylla

  18. An animal component free medium that promotes the growth of various animal cell lines for the production of viral vaccines.

    PubMed

    Rourou, Samia; Ben Ayed, Yousr; Trabelsi, Khaled; Majoul, Samy; Kallel, Héla

    2014-05-19

    IPT-AFM is a proprietary animal component free medium that was developed for rabies virus (strain LP 2061) production in Vero cells. In the present work, we demonstrated the versatility of this medium and its ability to sustain the growth of other cell lines and different virus strains. Here, three models were presented: Vero cells/rabies virus (strain LP 2061), MRC-5 cells/measles virus (strain AIK-C) and BHK-21 cells/rabies virus (strain PV-BHK21). The cell lines were first adapted to grow in IPT-AFM, by progressive reduction of the amount of serum in the culture medium. After their adaptation, BHK-21 cells grew in suspension by forming clumps, whereas MRC-5 cells remained adherent. Then, kinetics of cell growth were studied in agitated cultures for both cell lines. In addition, kinetics of virus replication were investigated. PMID:24583007

  19. 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 different from that of the ground-base controls and had a same 6 polymorphic bands and a same 0.23% DNA mutation. For the 49 second-generation plants derived from the Mir-flown No. 6 seed, 7 DNA bands were polymorphic with 0.27% polymorphism among 2564 amplified DNA bands. With only one exception among those 49 second-generation plants amplified by primer pair (E3: ACA, M3: CAG), one DNA band disappeared in 48 second-generation plants and in the original Mir-flown No. 6 plant, compared to the ground-based controls. Among the 49 second-generation plants generated from the Mir-flown No. 6 seed, the DNA band types of 48 second-generation plants were different from that of the ground-base controls and had a same 7 polymorphic bands and a same 0.27% DNA mutation. Our results indicated that leaf cell ultrastructures had been altered and heredity variations had been induced by seeds being exposed to a long-term outer-space environment. Further research is needed to elucidate the dynamics and mechanisms resulting in such variations. Plant biology studies in the space environment may open potential approaches to induce mutations and to screen new plant varieties by ground-based selections among spaceflight treated seeds or seedlings.

  20. Floc Formation by Azospirillum lipoferum Grown on Poly-?-Hydroxybutyrate †

    PubMed Central

    Bleakley, Bruce H.; Gaskins, Murray H.; Hubbell, David H.; Zam, Stephan G.

    1988-01-01

    Azospirillum lipoferum RG6xx was grown under conditions similar to those resulting in encystment of Azotobacter spp. A. lipoferum produced cells of uniform shape when grown on nitrogen-free ?-hydroxybutyrate agar. Cells accumulated poly-?-hydroxybutyrate and often grew as chains or filaments that eventually lost motility and formed capsules. Within 1 week, vegetative A. lipoferum inocula were converted into microflocs arising from filaments or chains. Cells within microflocs were pleomorphic, contained much poly-?-hydroxybutyrate, and were encapsulated. Some cells had a cystlike morphology. Up to 57% of the dry weight of encapsulated flocs was poly-?-hydroxybutyrate, whereas vegetative cells grown in broth with combined nitrogen had only 3% of their dry weight as poly-?-hydroxybutyrate. Neither encapsulated cells in flocs nor nonencapsulated vegetative cells were significantly desiccation resistant. Under starvation conditions (9 days) only 25% of encapsulated cells remained viable, whereas vegetative cells multiplied severalfold. In short-term germination experiments with encapsulated flocs, nitrate, ammonium, and soil extract promoted formation of motile vegetative cells. Most cells in treatments lacking combined nitrogen eventually depleted their visible poly-?-hydroxybutyrate reserves without germinating. The remaining cells retained the reserve polymer and underwent size reduction. Images PMID:16347792

  1. Enhancement of chemotaxis in Spirochaeta aurantia grown under conditions of nutrient limitation.

    PubMed

    Terracciano, J S; Canale-Parola, E

    1984-07-01

    Spirochaeta aurantia M1 cells were grown in a chemostat under conditions of energy and carbon source limitation. The chemotactic responses of the chemostat-grown cells were compared with those of S. aurantia cells grown in batch culture in the presence of excess energy and carbon source. Chemotactic responses were measured by determining the number of cells that entered a capillary tube containing a solution of attractant. S. aurantia cells grown in the chemostat under energy and carbon source limitation exhibited enhanced chemotactic responses and detected lower concentrations of attractant, as compared with cells grown in batch culture. The chemotactic response toward an attractant was specifically enhanced when that attractant was the growth-limiting energy and carbon source. The medium used contained either D-glucose or D-xylose as the sole energy and carbon source. Cells had the greatest chemotactic response toward glucose when grown at a dilution rate (D) of 0.045 h-1 under glucose limitation and toward xylose when grown at D = 0.06 h-1 under xylose limitation. When cells were grown under glucose limitation (D = 0.045 h-1), they sensed concentrations of attractant (glucose) ca. 1,000 times lower than those sensed by batch-grown cells. A similar enhancement of sensing ability (toward xylose) was observed in cells grown under xylose limitation. The results indicated that S. aurantia cells are able to regulate their chemosensory system in response to nutrient limitation. Maximum enhancement of chemotaxis occurs in cells growing at very low concentrations of energy and carbon source. Most likely, this property provides the spirochetes with competitive advantages when the availability of nutrients becomes severely limited in their habitats. PMID:6735977

  2. Quantitation of dengue virus specific CD4+ T cells by intracellular cytokine staining

    Microsoft Academic Search

    Marlou M. Mangada; Francis A. Ennis; Alan L. Rothman

    2004-01-01

    We developed an intracellular cytokine staining assay to quantify dengue specific memory T cells elicited by a primary dengue virus (DEN) infection. Peripheral blood mononuclear cells (PBMC) of volunteers who received experimental live attenuated monovalent DEN vaccines were stimulated with glutaraldehyde-inactivated dengue-infected Vero cell culture lysates from all four DEN serotypes. CD4+ T cell frequencies to previously identified MHC class

  3. Inhibition of in vitro cell adherence of Clostridium difficile by Saccharomyces boulardii

    Microsoft Academic Search

    Albert Tasteyre; Marie-Claude Barc; Tuomo Karjalainen; Pierre Bourlioux; Anne Collignon

    2002-01-01

    The influence on the adherence of Clostridium difficile to Vero cells of the yeastSaccharomyces boulardii , the yeast fractions (cytoplasm and cell wall) and the culture supernatant was investigated in vitro. C. difficile adherence was significantly inhibited when bacteria were pre-incubated with the whole yeast and the cell wall fraction; this adherence inhibition was dose-dependent. The cell wall fraction also

  4. Poly(N-vinylpyrrolidone)-decorated reduced graphene oxide with ZnO grown in situ as a cathode buffer layer for polymer solar cells.

    PubMed

    Hu, Ting; Chen, Lie; Yuan, Kai; Chen, Yiwang

    2014-12-15

    A ZnO@reduced graphene oxide-poly(N-vinylpyrrolidone) (ZnO@RGO-PVP) nanocomposite, prepared by in situ growth of ZnO nanoparticles on PVP-decorated RGO (RGO-PVP) was developed as a cathode buffer layer for improving the performance of polymer solar cells (PSCs). PVP not only favors homogeneous distribution of the RGO through the strong ?-? interactions between graphene and PVP molecules, but also acts as a stabilizer and bridge to control the in situ growth of sol-gel-derived ZnO nanoparticles on the surface of the graphene. At the same time, RGO provides a conductive connection for independent dispersion of ZnO nanoparticles to form uniform nanoclusters with fewer domain boundaries and surface traps. Moreover, the LUMO level of ZnO is effectively improved by modification with RGO-PVP. Compared to bare ZnO, a ZnO@RGO-PVP cathode buffer layer substantially reduces the recombination of carriers, increases the electrical conductivity, and enhances electron extraction. Consequently, the power conversion efficiency of an inverted device based on thieno[3,4-b]thiophene/benzodithiophene (PTB7):[6,6]-phenyl C71 -butyric acid methyl ester (PC71 BM) with ZnO@RGO-PVP as cathode buffer layer was greatly improved to 7.5?% with improved long-term stability. The results reveal that ZnO@RGO-PVP is universally applicable as a cathode buffer layer for improving the performance of PSCs. PMID:25345881

  5. Nucleolus in clinostat-grown plants

    SciTech Connect

    Shen-Miller, J.; Dannenhoffer, J. (Univ. of California, Los Angeles (United States)); Hinchman, R. (Argonne National Lab., IL (United States))

    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.

  6. Use of SLAM and PVRL4 and identification of pro-HB-EGF as cell entry receptors for wild type phocine distemper virus.

    PubMed

    Melia, Mary M; Earle, John Philip; Abdullah, Haniah; Reaney, Katherine; Tangy, Frederic; Cosby, Sara Louise

    2014-01-01

    Signalling lymphocyte activation molecule (SLAM) has been identified as an immune cell receptor for the morbilliviruses, measles (MV), canine distemper (CDV), rinderpest and peste des petits ruminants (PPRV) viruses, while CD46 is a receptor for vaccine strains of MV. More recently poliovirus like receptor 4 (PVRL4), also known as nectin 4, has been identified as a receptor for MV, CDV and PPRV on the basolateral surface of polarised epithelial cells. PVRL4 is also up-regulated by MV in human brain endothelial cells. Utilisation of PVRL4 as a receptor by phocine distemper virus (PDV) remains to be demonstrated as well as confirmation of use of SLAM. We have observed that unlike wild type (wt) MV or wtCDV, wtPDV strains replicate in African green monkey kidney Vero cells without prior adaptation, suggesting the use of a further receptor. We therefore examined candidate molecules, glycosaminoglycans (GAG) and the tetraspan proteins, integrin ? and the membrane bound form of heparin binding epithelial growth factor (proHB-EGF),for receptor usage by wtPDV in Vero cells. We show that wtPDV replicates in Chinese hamster ovary (CHO) cells expressing SLAM and PVRL4. Similar wtPDV titres are produced in Vero and VeroSLAM cells but more limited fusion occurs in the latter. Infection of Vero cells was not inhibited by anti-CD46 antibody. Removal/disruption of GAG decreased fusion but not the titre of virus. Treatment with anti-integrin ? antibody increased rather than decreased infection of Vero cells by wtPDV. However, infection was inhibited by antibody to HB-EGF and the virus replicated in CHO-proHB-EGF cells, indicating use of this molecule as a receptor. Common use of SLAM and PVRL4 by morbilliviruses increases the possibility of cross-species infection. Lack of a requirement for wtPDV adaptation to Vero cells raises the possibility of usage of proHB-EGF as a receptor in vivo but requires further investigation. PMID:25171206

  7. Use of SLAM and PVRL4 and Identification of Pro-HB-EGF as Cell Entry Receptors for Wild Type Phocine Distemper Virus

    PubMed Central

    Reaney, Katherine; Tangy, Frederic; Cosby, Sara Louise

    2014-01-01

    Signalling lymphocyte activation molecule (SLAM) has been identified as an immune cell receptor for the morbilliviruses, measles (MV), canine distemper (CDV), rinderpest and peste des petits ruminants (PPRV) viruses, while CD46 is a receptor for vaccine strains of MV. More recently poliovirus like receptor 4 (PVRL4), also known as nectin 4, has been identified as a receptor for MV, CDV and PPRV on the basolateral surface of polarised epithelial cells. PVRL4 is also up-regulated by MV in human brain endothelial cells. Utilisation of PVRL4 as a receptor by phocine distemper virus (PDV) remains to be demonstrated as well as confirmation of use of SLAM. We have observed that unlike wild type (wt) MV or wtCDV, wtPDV strains replicate in African green monkey kidney Vero cells without prior adaptation, suggesting the use of a further receptor. We therefore examined candidate molecules, glycosaminoglycans (GAG) and the tetraspan proteins, integrin ? and the membrane bound form of heparin binding epithelial growth factor (proHB-EGF),for receptor usage by wtPDV in Vero cells. We show that wtPDV replicates in Chinese hamster ovary (CHO) cells expressing SLAM and PVRL4. Similar wtPDV titres are produced in Vero and VeroSLAM cells but more limited fusion occurs in the latter. Infection of Vero cells was not inhibited by anti-CD46 antibody. Removal/disruption of GAG decreased fusion but not the titre of virus. Treatment with anti-integrin ? antibody increased rather than decreased infection of Vero cells by wtPDV. However, infection was inhibited by antibody to HB-EGF and the virus replicated in CHO-proHB-EGF cells, indicating use of this molecule as a receptor. Common use of SLAM and PVRL4 by morbilliviruses increases the possibility of cross-species infection. Lack of a requirement for wtPDV adaptation to Vero cells raises the possibility of usage of proHB-EGF as a receptor in vivo but requires further investigation. PMID:25171206

  8. Development of a novel, multi-analyte biosensor system for assaying cell division: Identification of cell proliferation\\/death precursor events

    Microsoft Academic Search

    S. Kintzios; I. Marinopoulou; G. Moschopoulou; O. Mangana; K. Nomikou; K. Endo; I. Papanastasiou; A. Simonian

    2006-01-01

    A novel, miniaturized biosensor system was created by combining the electrophysiological response of immobilized cells with superoxide-sensing technology, optical and fluorescence microscopy. Vero cells were immobilized in a calcium alginate matrix (at a density of 1.7×106cellsml?1). A 0.5cm×0.5cm piece of cell-containing gel matrix was aseptically adhered on a glass microscope slide with a microfabricated gold electrode array, sealed with a

  9. Extremely low-frequency electromagnetic fields cause DNA strand breaks in normal cells

    PubMed Central

    2014-01-01

    Background Extremely low frequency electromagnetic fields aren’t considered as a real carcinogenic agent despite the fact that some studies have showed impairment of the DNA integrity in different cells lines. The aim of this study was evaluation of the late effects of a 100 Hz and 5.6 mT electromagnetic field, applied continuously or discontinuously, on the DNA integrity of Vero cells assessed by alkaline Comet assay and by cell cycle analysis. Normal Vero cells were exposed to extremely low frequency electromagnetic fields (100 Hz, 5.6 mT) for 45 minutes. The Comet assay and cell cycle analysis were performed 48 hours after the treatment. Results Exposed samples presented an increase of the number of cells with high damaged DNA as compared with non-exposed cells. Quantitative evaluation of the comet assay showed a significantly (<0.001) increase of the tail lengths, of the quantity of DNA in tail and of Olive tail moments, respectively. Cell cycle analysis showed an increase of the frequency of the cells in S phase, proving the occurrence of single strand breaks. The most probable mechanism of induction of the registered effects is the production of different types of reactive oxygen species. Conclusions The analysis of the registered comet indices and of cell cycle showed that extremely low frequency electromagnetic field of 100 Hz and 5.6 mT had a genotoxic impact on Vero cells. PMID:24401758

  10. Characterization of silicon crystals grown by the heat exchanger method

    SciTech Connect

    Hyland, S.; Dumas, K.A.; Engelbrecht, J.A.A.; Leung, D.; Schwuttke, G.M.

    1983-05-01

    Silicon ingots grown by the Heat Exchanger Method (HEM) as large as 45 kg in mass (34 cm x 34 cm x 17 cm) are characterized electrically and structurally. The defect state in the crystal is related to the solar cell efficiency. Such characterization indicates that the solar cell efficiency of HEM crystals is limited by the crystal perfection, but that HEM silicon has the potential to yield silicon with quality comparable to Cz grown silicon. A new approach to grow HEM material of better quality is discussed.

  11. 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.

  12. Apoptosis as a Cause of Death in Measles Virus-Infected Cells

    Microsoft Academic Search

    LISA M. ESOLEN; SUK W. PARK; J. MARIE HARDWICK; ANDDIANE E. GRIFFIN

    1995-01-01

    To determine the mechanism of measles virus-induced cell death, we studied the infection of Vero cells and monocytic cell lines with wild-type (Chicago-1) and vaccine (Edmonston) strains of measles virus. DNA fragmentationindicativeofapoptosiswasapparentbyflowcytometry,agarosegelelectrophoresis,andelectron microscopy. Within syncytia, DNA strand breaks were demonstrated by end labeling with terminal transferase and then by visualization. A number of viruses have recently been shown to cause

  13. Investigation of the uptake of drugs, carcinogens and mutagens by individual mammalian cells using a scanning proton microprobe

    NASA Astrophysics Data System (ADS)

    Cholewa, M.; Turnbull, I. F.; Legge, G. J. F.; Weigold, H.; Marcuccio, S. M.; Holan, G.; Tomlinson, E.; Wright, P. J.; Dillon, C. T.; Lay, P. A.; Bonin, A. M.

    1995-09-01

    The use of micro-PIXE [1] in measuring the quantitative uptake of drugs containing metal atoms by individual Vero cells (African green monkey kidney cell line) and V79 Chinese hamster lung cells is demonstrated. One class of drugs, heteropolytungstates, which are being assessed for activity against the HIV virus, were studied using Vero cells. The cellular uptake of a series of chromium compounds, including carcinogens and mutagens, in which the metal oxidation state was either (III), (V) or (VI), was measured using V79 cells. It was found that, unlike any other techniques, scanning proton microprobe (SPM) offers both the sensitivity and spatial resolution to carry out unicellular analysis. The use of cultured cell lines in these analyses was shown to have distinct advantages over cells such as peripheral blood lymphocytes (PBLs).

  14. Deletion of the S component inverted repeat sequence c ? and the nonessential genes U s 1 through U s 5 from the herpes simplex virus type 1 genome substantially impairs productive viral infection in cell culture and pathogenesis in the rat central nervous system

    Microsoft Academic Search

    Siyamak Rasty; P Luigi Poliani; David J Fink; Joseph C Glorioso

    1997-01-01

    A distinctive feature of the genetic make-up of herpes simplex virus type 1 (HSV-1), a human neurotropic virus, is that approximately half of the 81 known viral genes are not absolutely required for productive infection in Vero cells, and most can be individually deleted without substantially impairing viral replication in cell culture. If large blocks of contiguous viral genes could

  15. 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.

  16. Bioengineered Dental Tissues Grown in the Rat Jaw

    Microsoft Academic Search

    S. E. Duailibi; M. T. Duailibi; W. Zhang; R. Asrican; J. P. Vacanti; P. C. Yelick

    2008-01-01

    Our long-term objective is to develop methods to form, in the jaw, bioengineered replacement teeth that exhibit physical properties and functions similar to those of natural teeth. Our results show that cultured rat tooth bud cells, seeded onto biodegradable scaffolds, implanted into the jaws of adult rat hosts and grown for 12 weeks, formed small, organized, bioengineered tooth crowns, containing

  17. Penetration and intracellular growth of Brucella abortus in nonphagocytic cells in vitro.

    PubMed Central

    Detilleux, P G; Deyoe, B L; Cheville, N F

    1990-01-01

    In pregnant ruminants, Brucella abortus localizes and replicates within the rough endoplasmic reticulum of trophoblastic epithelial cells. In this study, Vero cells were exposed to B. abortus to investigate its internalization and intracellular growth in nonphagocytic cells. A new double-fluorescence staining procedure to discriminate between extracellular and intracellular bacteria was developed. Studies with the double-fluorescence staining procedure and quantitative bacteriologic culture of disrupted host cells showed that various B. abortus strains replicated within Vero cells, including smooth virulent (strains 2308S and 544), smooth attenuated (strain 19), and rough (strains 45/20 and 2308R) strains. Rough brucellae were more adherent and entered a greater number of Vero cells. Intracellular replication occurred in a larger percentage of cells with smooth virulent (2308S and 544) strains than with smooth attenuated (19) or rough (45/20 and 2308R) strains. Differences in adhesiveness and invasiveness were correlated to hydrophobicity of the organism, as measured by hydrocarbon adherence. Ultrastructurally, intracellular smooth (2308S) and rough (45/20) brucellae were consistently found within cisternae of the rough endoplasmic reticulum and nuclear envelope. The results suggest that transfer to the rough endoplasmic reticulum is the limiting step in the infection of nonphagocytic cells by B. abortus. Images PMID:2114362

  18. Tissue grown in space in NASA Bioreactor

    NASA Technical Reports Server (NTRS)

    1998-01-01

    For 5 days on the STS-70 mission, a bioreactor cultivated human colon cancer cells, such as the culture section shown here, which grew to 30 times the volume of control specimens grown on Earth. This significant result was reproduced on STS-85 which grew mature structures that more closely match what are found in tumors in humans. The two white circles within the tumor are part of a plastic lattice that helped the cells associate. 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). 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.

  19. Characterization of thin film cadmium sulfide grown using a modified chemical bath deposition process

    Microsoft Academic Search

    M. D. Archbold; D. P. Halliday; K. Durose; T. P. A. Hase; D. Smyth-Boyle; K. Govender

    2005-01-01

    Cadmium sulfide polycrystalline films with potential for application as a solar cell window layer have been grown by a modified chemical bath deposition process, using ethylenediamine as a complexing agent and employing direct heating of the substrate. Films have been characterized using atomic force microscopy, scanning electron microscopy, grazing incidence X-ray diffraction, photoluminescence, photoconductivity, and optical absorption. Both as-grown films

  20. Tissue grown in space in NASA Bioreactor

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Dr. Lisa E. Freed of the Massachusetts Institute of Technology and her colleagues have reported that initially disc-like specimens tend to become spherical in space, demonstrating that tissues can grow and differentiate into distinct structures in microgravity. The Mir Increment 3 (Sept. 16, 1996 - Jan. 22, 1997) samples were smaller, more spherical, and mechanically weaker than Earth-grown control samples. These results demonstrate the feasibility of microgravity tissue engineering and may have implications for long human space voyages and for treating musculoskeletal disorders on earth. Final samples from Mir and Earth appeared histologically cartilaginous throughout their entire cross sections (5-8 mm thick), with the exception of fibrous outer capsules. Constructs grown on Earth (A) appeared to have a more organized extracellular matrix with more uniform collagen orientation as compared with constructs grown on Mir (B), but the average collagen fiber diameter was similar in the two groups (22 +- 2 nm) and comparable to that previously reported for developing articular cartilage. Randomly oriented collagen in Mir samples would be consistent with previous reports that microgravity disrupts fibrillogenesis. These are transmission electron micrographs of constructs from Mir (A) and Earth (B) groups at magnifications of x3,500 and x120,000 (Inset). 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. Credit: Proceedings of the National Academy of Sciences.

  1. Tissue grown in space in NASA Bioreactor

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Dr. Lisa E. Freed of the Massachusetts Institute of Technology and her colleagues have reported that initially disc-like specimens of cartilage tend to become spherical in space, demonstrating that tissues can grow and differentiate into distinct structures in microgravity. The Mir Increment 3 (Sept. 16, 1996 - Jan. 22, 1997) samples were smaller, more spherical, and mechanically weaker than Earth-grown control samples. These results demonstrate the feasibility of microgravity tissue engineering and may have implications for long human space voyages and for treating musculoskeletal disorders on earth. Constructs grown on Mir (A) tended to become more spherical, whereas those grown on Earth (B) maintained their initial disc shape. These findings might be related to differences in cultivation conditions, i.e., videotapes showed that constructs floated freely in microgravity but settled and collided with the rotating vessel wall at 1g (Earth's gravity). In particular, on Mir the constructs were exposed to uniform shear and mass transfer at all surfaces such that the tissue grew equally in all directions, whereas on Earth the settling of discoid constructs tended to align their flat circular areas perpendicular to the direction of motion, increasing shear and mass transfer circumferentially such that the tissue grew preferentially in the radial direction. A and B are full cross sections of constructs from Mir and Earth groups shown at 10-power. C and D are representative areas at the construct surfaces enlarged to 200-power. They are stained red with safranin-O. NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. 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). Photo credit: Proceedings of the National Academy of Sciences.

  2. Nuclear factor of activated T-cells (NFAT) plays a role in SV40 infection

    SciTech Connect

    Manley, Kate [Graduate Program in Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912 (United States); O'Hara, Bethany A. [Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912 (United States); Atwood, Walter J. [Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912 (United States)], E-mail: Walter_Atwood@Brown.edu

    2008-03-01

    Recent evidence highlighted a role for the transcription factor, nuclear factor of activated T-cells (NFAT), in the transcription of the human polyomavirus JCV. Here we show that NFAT is also important in the transcriptional control of the related polyomavirus, Simian Virus 40 (SV40). Inhibition of NFAT activity reduced SV40 infection of Vero, 293A, and HeLa cells, and this block occurred at the stage of viral transcription. Both NFAT3 and NFAT4 bound to the SV40 promoter through {kappa}B sites located within the 72 bp repeated enhancer region. In Vero cells, NFAT was involved in late transcription, but in HeLa and 293A cells both early and late viral transcription required NFAT activity. SV40 large T-Ag was found to increase NFAT activity and provided a positive feedback loop to transactivate the SV40 promoter.

  3. Response to copper of Acidithiobacillus ferrooxidans ATCC 23270 grown in elemental sulfur.

    PubMed

    Almárcegui, Rodrigo J; Navarro, Claudio A; Paradela, Alberto; Albar, Juan Pablo; von Bernath, Diego; Jerez, Carlos A

    2014-11-01

    The response of Acidithiobacillus ferrooxidans ATCC 23270 to copper was analyzed in sulfur-grown cells by using quantitative proteomics. Forty-seven proteins showed altered levels in cells grown in the presence of 50 mM copper sulfate. Of these proteins, 24 were up-regulated and 23 down-regulated. As seen before in ferrous iron-grown cells, there was a notorious up-regulation of RND-type Cus systems and different RND-type efflux pumps, indicating that these proteins are very important in copper resistance. Copper also triggered the down-regulation of the major outer membrane porin of A. ferrooxidans in sulfur-grown bacteria, suggesting they respond to the metal by decreasing the influx of cations into the cell. On the contrary, copper in sulfur-grown cells caused an overexpression of putative TadA and TadB proteins known to be essential for biofilm formation in bacteria. Surprisingly, sulfur-grown microorganisms showed increased levels of proteins related with energy generation (rus and petII operons) in the presence of copper. Although rus operon is overexpressed mainly in cells grown in ferrous iron, the up-regulation of rusticyanin in sulfur indicates a possible role for this protein in copper resistance as well. Finally, copper response in A. ferrooxidans appears to be influenced by the substrate being oxidized by the microorganism. PMID:25041950

  4. Thermal Stability of Corrugated Epitaxial Graphene Grown on Re(0001)

    NASA Astrophysics Data System (ADS)

    Miniussi, E.; Pozzo, M.; Baraldi, A.; Vesselli, E.; Zhan, R. R.; Comelli, G.; Mente?, T. O.; Niño, M. A.; Locatelli, A.; Lizzit, S.; Alfè, D.

    2011-05-01

    We report on a novel approach to determine the relationship between the corrugation and the thermal stability of epitaxial graphene grown on a strongly interacting substrate. According to our density functional theory calculations, the C single layer grown on Re(0001) is strongly corrugated, with a buckling of 1.6 Å, yielding a simulated C 1s core level spectrum which is in excellent agreement with the experimental one. We found that corrugation is closely knit with the thermal stability of the C network: C-C bond breaking is favored in the strongly buckled regions of the moiré cell, though it requires the presence of diffusing graphene layer vacancies.

  5. The expression of native and cultured RPE grown on different matrices.

    PubMed

    Tian, Jane; Ishibashi, Kazuki; Handa, James T

    2004-04-13

    The purpose of this work was to determine the expression profiles of retinal pigment epithelial (RPE) cells grown on different matrices and to assess the degree of culture-induced artifact by comparing the profiles to native RPE. Visually confluent ARPE-19 cells were grown on plastic, Matrigel, collagen I, collagen IV, laminin, and fibronectin for 1 wk, and serum was withdrawn for 3 days. Morphologically normal, macular RPE cells were laser-capture microdissected from three human eye globes. Total RNA was extracted from 5,000 cells and reverse transcribed, and radiolabeled cDNA probes were hybridized to an array containing 4,325 known genes. Arrays were assessed by cluster analysis and significance analysis of microarrays (SAM). Real-time RT-PCR was used to validate differentially expressed genes. Despite similar morphology, ARPE-19 demonstrated different expression profiles when grown on different matrices. Cluster analysis showed that cells grown on collagen IV, laminin, and fibronectin had similar profiles that were distinct from cells grown on collagen I. Cells grown on plastic clustered closest to native RPE. This expression pattern was confirmed with supervised cluster analyses. The number of differentially expressed genes, function of differentially expressed genes, and profile of expressed and unexpressed genes suggest that the overall expression profile of cultured cells is significantly different from native RPE. RPE cells grown on collagen IV, laminin, and fibronectin have profiles more similar than cells grown on plastic, Matrigel, or collagen I. The overall mRNA phenotype, however, is different from morphologically normal, native macular RPE. PMID:14982971

  6. In situ quantification of microcarrier animal cell cultures using near-infrared spectroscopy

    Microsoft Academic Search

    Emma Petiot; Patrick Bernard-Moulin; Thierry Magadoux; Cécile Gény; Hervé Pinton; Annie Marc

    2010-01-01

    In-line monitoring tools are still required to understand and control animal cell processes, particularly in the case of vaccine production. Here, in situ near-infrared spectroscopy (NIRS) quantification of components in culture media was performed using microcarrier-based cultivations of adherent Vero cells. Because microcarriers were found to interfere with NIRS spectra acquisition, a suitable and innovative in situ calibration was developed

  7. Cytotoxic effects of mycotoxin combinations in mammalian kidney cells.

    PubMed

    Ruiz, María-José; Macáková, Petra; Juan-García, Ana; Font, Guillermina

    2011-10-01

    The cytotoxicity of three Fusarium mycotoxins (beauvericin, deoxynivalenol and T-2 toxin) has been investigated using the NR assay, after 24, 48 and 72h of incubation. The IC(50) values ranged from 6.77 to 11.08, 3.30 to 10.00 and 0.004 to 0.005 for beauvericin, deoxynivalenol and T-2 toxin, respectively. Once the potential interaction has been detected, a quantitative assessment is necessary to ensure and characterize these interactions, that is, each mycotoxin contributes to the toxic effect in accord with its own potency. Combination of mycotoxins was determined in Vero cells after 24, 48 and 72h of exposure. Isobolograms and median effect method of Chou and Talalay were used to assess the nature and quantitative aspects of interaction observed between studied mycotoxins. Median effect analysis was used to calculate the combination index (CI) with values >1 indicating synergism, 1 additive effect, and <1 antagonism. CI values of BEA+DON (1.22-2.74), BEA+T-2 toxin (1.43-5.89), DON+T-2 toxin (3.13-7.62) and BEA+DON+T-2 toxin (1.32-2.68) for 24, 48 and 72h produced antagonistic effects in Vero cells. The highest antagonistic effect in Vero cells was observed with binary DON and T-2 toxin mixture. PMID:21798303

  8. Fast Plants Grown in Light and Dark

    NSDL National Science Digital Library

    Lauffer, Hedi Baxter

    Photograph of two five-day-old Standard Fast Plants grown in Bottle Growing Systems--one grown with full light, one grown in the dark. This is a good example of a quick way to stimulate discussion about the matter and energy sources and needs that germinating seeds have in comparison to seedlings or plants.

  9. Entrapment of Bacteria in Fluid Inclusions in Laboratory-Grown Halite

    E-print Network

    Adamski, J.C.; Roberts, Jennifer A.; Goldstein, Robert H.

    2006-08-17

    Cells of the bacterium Pseudomonas aeruginosa, which were genetically modified to produce green fluorescent protein, were entrapped in fluid inclusions in laboratory-grown halite. The bacteria were used to inoculate NaCl-saturated aqueous solutions...

  10. Physical and Microstructural Properties of Radio-Frequency Plasma-Enhanced Chemical Vapor Deposition Grown n-Type Phosphorus Doped Amorphous Carbon Films on the Contribution to Carbon-Based Solar Cells

    Microsoft Academic Search

    Mohamad Rusop; Hiroshi Ebisu; Mitsuhiro Adachi; Tetsuo Soga; Takashi Jimbo

    2005-01-01

    The physical and microstructural properties of phosphorus doped n-type amorphous carbon (n-C:P) films grown from a radio-frequency (rf) discharge in methane gas as a function of rf power (Prf) was previously determined, and their influence on the electronic properties is now analyzed. It is shown that Prf plays a major role in the deposition of n-C:P films. The Raman scattering,

  11. High-efficiency solar cells fabricated from direct-current magnetron sputtered n-indium tin oxide onto p-InP grown by atmospheric pressure metalorganic vapor phase epitaxy

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

    An attempt is made to improve device efficiencies by depositing indium tin oxide onto epitaxially grown p-InP on p(+)-InP substrates. This leads to a reduction in the device series resistance, high-quality reproducible surfaces, and an improvement in the transport properties of the base layer. Moreover, many of the facets associated with badly characterized bulk liquid encapsulated Czochralski substrates used in previous investigations are removed in this way.

  12. Mixed infections in vitro with different Chlamydiaceae strains and a cell culture adapted porcine epidemic diarrhea virus

    Microsoft Academic Search

    Angela Stuedli; Paula Grest; Irene Schiller; Andreas Pospischil

    2005-01-01

    Assuming a synergistic or additive effect of Chlamydiaceae in coexistence with other enteropathogenic agents, the viral\\/bacterial interaction between a cell culture adapted porcine epidemic diarrhea virus (ca-PEDV) and different Chlamydiaceae strains was studied in vitro. Vero cells were dually infected with ca-PEDV and one of the three chlamydial strains Chlamydia trachomatis S45, Chlamydophila abortus S26\\/3 or Chlamydophila pecorum 1710S. Three

  13. Antibacterial effect of theaflavin, polyphenon 60 (Camellia sinensis) and Euphorbia hirta on Shigella spp.--a cell culture study.

    PubMed

    Vijaya, K; Ananthan, S; Nalini, R

    1995-12-01

    Antibacterial effect of compounds extracted from Camellia sinensis L. and the methanol extract of Euphorbia hirta L. were studied against dysentery causing Shigella spp. using the Vero cell line. Cytotoxicity studies of the extracts were performed using the cell line and the non-cytotoxic concentration of the extract was tested for antibacterial activity against the cytopathic dose of the pathogen. These extracts were found to be non-cytotoxic and effective antibacterial agents. PMID:8847884

  14. Phase I clinical trial with IL-2-transfected xenogeneic cells administered in subcutaneous metastatic tumours: clinical and immunological findings

    PubMed Central

    Tartour, E; Mehtali, M; Sastre-Garau, X; Joyeux, I; Mathiot, C; Pleau, J M; Squiban, P; Rochlitz, C; Courtney, M; Jantscheff, P; Herrmann, R; Pouillart, P; Fridman, W H; Dorval, T

    2000-01-01

    Various studies have emphasized an immunodepression state observed at the tumour site. To reverse this defect and based upon animal studies, we initiated a phase I clinical trial of gene therapy in which various doses of xenogeneic monkey fibroblasts (Vero cells) genetically engineered to produce human IL-2 were administered intratumorally in 8 patients with metastatic solid tumours. No severe adverse effect was observed in the 8 patients analysed during this clinical trial even in the highest dose (5 ¥ 107 cells) group. This absence of toxicity seems to be associated with rapid elimination of Vero-IL-2 cells from the organism. Indeed, exogenous IL-2 mRNA could no longer be detected in the peripheral whole blood 48 hours after Vero-IL-2 cell administration. In addition, we did not find any expression of exogenous IL-2 mRNA in post-therapeutic lesions removed 29 days after the start of therapy. A major finding of this trial concerns the two histological responses of two treated subcutaneous nodules not associated with an apparent clinical response. The relationship between local treatment and tumour regression was supported by replacement of tumour cells by inflammatory cells in regressing lesions and marked induction of T and natural killer cell derived cytokines (IL-2, IL-4, IFNg …) in post-therapeutic lesions analysed 28 days after the start of Vero-IL-2 administration. Gene therapy using xenogeneic cells as vehicle may therefore present certain advantages over other vectors, such as its complete absence of toxicity. Furthermore, the in vivo biological effect of immunostimulatory genes, i.e IL-2-, may be potentiated by the xenogeneic rejection reaction. © 2000 Cancer Research Campaign http://www.bjcancer.com PMID:11076653

  15. Generation of influenza vaccine viruses on Vero cells by reverse genetics: an H5N1 candidate vaccine strain produced under a quality system

    Microsoft Academic Search

    Carolyn Nicolson; Diane Major; John M. Wood; James S. Robertson

    2005-01-01

    Human influenza vaccine reference strains are prepared as required when an antigenically new strain is recommended by WHO for inclusion in the vaccine. Currently, for influenza A, these strains are produced by a double infection of embryonated hens’ eggs using the recommended strain and the laboratory strain PR8 which grows to high titre in eggs, in order to produce a

  16. Carbonic anhydrase activity in acetate grown Methanosarcina barkeri

    Microsoft Academic Search

    Marion Karrasch; Michael Bott; Rudolf K. Thauer

    1989-01-01

    Cell extracts (27000xg supernatant) of acetate grown Methanosarcina barkeri were found to have carbonic anhydrase activity (0.41 U\\/mg protein), which was lost upon heating or incubation with proteinase K. The activity was inhibited by Diamox (apparent Ki=0.5 mM), by azide (apparent Ki=1 mM), and by cyanide (apparent Ki=0.02 mM). These and other properties indicate that the archaebacterium contains the enzyme

  17. Listeria monocytogenes grown at 7° C shows reduced acid survival and an altered transcriptional response to acid shock compared to L. monocytogenes grown at 37° C.

    PubMed

    Ivy, R A; Wiedmann, M; Boor, K J

    2012-06-01

    Survival of the food-borne pathogen Listeria monocytogenes in acidic environments (e.g., in the human stomach) is vital to its transmission. Refrigerated, ready-to-eat foods have been sources of listeriosis outbreaks. The purpose of this study was to determine whether growth at a low temperature (i.e., 7°C) affects L. monocytogenes survival or gene transcription after exposure to a simulated gastric environment (i.e., acid shock at 37°C). L. monocytogenes cells grown at 7°C were less resistant to artificial gastric fluid (AGF) or acidified brain heart infusion broth (ABHI) than bacteria grown at higher temperatures (i.e., 30°C or 37°C). For L. monocytogenes grown at 7°C, stationary-phase cells were more resistant to ABHI than log-phase cells, indicating that both temperature and growth phase affect acid survival. Microarray transcriptomic analysis revealed that the number and functional categories of genes differentially expressed after acid shock differed according to both growth temperature and growth phase. The acid response of L. monocytogenes grown to log phase at 37°C involved stress-related transcriptional regulators (i.e., ?(B), ?(H), CtsR, and HrcA), some of which have been implicated in adaptation to the intracellular environment. In contrast, for bacteria grown at 7°C to stationary phase, acid exposure did not result in differential expression of the stress regulons examined. However, two large operons encoding bacteriophage-like proteins were induced, suggesting lysogenic prophage induction. The adaptive transcriptional response observed in 37°C-grown cells was largely absent in 7°C-grown cells, suggesting that temperatures commonly encountered during food storage and distribution affect the ability of L. monocytogenes to survive gastric passage and ultimately cause disease. PMID:22447604

  18. Strain Variation in Glycosaminoglycan Recognition Influences Cell-Type-Specific Binding by Lyme Disease Spirochetes

    Microsoft Academic Search

    NIKHAT PARVEEN; DOUGLAS ROBBINS; JOHN M. LEONG

    1999-01-01

    Lyme disease, a chronic multisystemic disorder that can affect the skin, heart, joints, and nervous system is caused by Borrelia burgdorferi sensu lato. Lyme disease spirochetes were previously shown to bind glycosamino- glycans (GAGs). In the current study, the GAG-binding properties of eight Lyme disease strains were deter- mined. Binding by two high-passage HB19 derivatives to Vero cells could not

  19. Harvesting microalgae grown on wastewater.

    PubMed

    Udom, Innocent; Zaribaf, Behnaz H; Halfhide, Trina; Gillie, Benjamin; Dalrymple, Omatoyo; Zhang, Qiong; Ergas, Sarina J

    2013-07-01

    The costs and life cycle impacts of microalgae harvesting for biofuel production were investigated. Algae were grown in semi-continuous culture in pilot-scale photobioreactors under natural light with anaerobic digester centrate as the feed source. Algae suspensions were collected and the optimal coagulant dosages for metal salts (alum, ferric chloride), cationic polymer (Zetag 8819), anionic polymer (E-38) and natural coagulants (Moringa Oleifera and Opuntia ficus-indica cactus) were determined using jar tests. The relative dewaterability of the algae cake was estimated by centrifugation. Alum, ferric chloride and cationic polymer could all achieve >91% algae recovery at optimal dosages. Life cycle assessment (LCA) and cost analysis results revealed that cationic polymer had the lowest cost but the highest environmental impacts, while ferric chloride had the highest cost and lowest environmental impacts. Based on the LCA results, belt presses are the recommended algae dewatering technology prior to oil extraction. PMID:23648758

  20. African Swine Fever Virus IAP Homologue Inhibits Caspase Activation and Promotes Cell Survival in Mammalian Cells

    PubMed Central

    Nogal, María L.; González de Buitrago, Gonzalo; Rodríguez, Clara; Cubelos, Beatriz; Carrascosa, Angel L.; Salas, María L.; Revilla, Yolanda

    2001-01-01

    African swine fever virus (ASFV) A224L is a member of the inhibitor of apoptosis protein (IAP) family. We have investigated the antiapoptotic function of the viral IAP both in stably transfected cells and in ASFV-infected cells. A224L was able to substantially inhibit caspase activity and cell death induced by treatment with tumor necrosis factor alpha and cycloheximide or staurosporine when overexpressed in Vero cells by gene transfection. We have also observed that ASFV infection induces caspase activation and apoptosis in Vero cells. Furthermore, using a deletion mutant of ASFV lacking the A224L gene, we have shown that the viral IAP modulates the proteolytic processing of the effector cell death protease caspase-3 and the apoptosis which are induced in the infected cells. Our findings indicate that A224L interacts with the proteolytic fragment of caspase-3 and inhibits the activity of this protease during ASFV infection. These observations could indicate a conserved mechanism of action for ASFV IAP and other IAP family members to suppress apoptosis. PMID:11222676

  1. The Herpes Simplex Virus Type 1 Regulatory Protein ICP27 Is Required for the Prevention of Apoptosis in Infected Human Cells

    Microsoft Academic Search

    MARTINE AUBERT; JOHN A. BLAHO

    1999-01-01

    The herpes simplex virus type 1 (HSV-1) ICP27 protein is an immediate-early or a protein which is essential for the optimal expression of late genes as well as the synthesis of viral DNA in cultures of Vero cells. Our specific goal was to characterize the replication of a virus incapable of synthesizing ICP27 in cultured human cells. We found that

  2. Microcarriers for high-pressure freezing and cryosectioning of adherent cells.

    PubMed

    Hagen, C; Grünewald, K

    2008-05-01

    A method is described employing microcarrier spheres of cross-linked dextran for obtaining ultra- and semithin vitreous sections from high-pressure frozen anchorage-dependent (mammalian) cells. Avoiding trypsination or scraping cells off from the culture surface, the presented approach allows for cryoimmobilization, cryosectioning and cryoelectron microscopy/tomography of frozen-hydrated cells in an unperturbed manner which is important to preserve the native state of, for instance, the cytoskeleton. Furthermore, our studies on the 'life cycle' of Herpes simplex virus in Vero cells demonstrate that cell monolayers on microcarrier beads are well suited for fluorescence microscopic characterization of the sample prior to high-pressure freezing. PMID:18445159

  3. Nectin4 Is an Epithelial Cell Receptor for Canine Distemper Virus and Involved in Neurovirulence

    PubMed Central

    Pratakpiriya, Watanyoo; Seki, Fumio; Otsuki, Noriyuki; Sakai, Kouji; Fukuhara, Hideo; Katamoto, Hiromu; Hirai, Takuya; Maenaka, Katsumi; Techangamsuwan, Somporn; Lan, Nguyen Thi; Takeda, Makoto

    2012-01-01

    Canine distemper virus (CDV) uses signaling lymphocyte activation molecule (SLAM), expressed on immune cells, as a receptor. However, epithelial and neural cells are also affected by CDV in vivo. Wild-type CDV strains showed efficient replication with syncytia in Vero cells expressing dog nectin4, and the infection was blocked by an anti-nectin4 antibody. In dogs with distemper, CDV antigen was preferentially detected in nectin4-positive neurons and epithelial cells, suggesting that nectin4 is an epithelial cell receptor for CDV and also involved in its neurovirulence. PMID:22761370

  4. SU-E-J-70: Feasibility Study of Dynamic Arc and IMRT Treatment Plans Utilizing Vero Treatment Unit and IPlan Planning Computer for SRS/FSRT Brain Cancer Patients

    SciTech Connect

    Huh, S; Lee, S; Dagan, R; Malyapa, R; Mendenhall, N; Mendenhall, W; Ho, M; Hough, D; Yam, M; Li, Z [UFPTI, Jacksonville, FL (United States)

    2014-06-01

    Purpose: To investigate the feasibility of utilizing Dynamic Arc (DA) and IMRT with 5mm MLC leaf of VERO treatment unit for SRS/FSRT brain cancer patients with non-invasive stereotactic treatments. The DA and IMRT plans using the VERO unit (BrainLab Inc, USA) are compared with cone-based planning and proton plans to evaluate their dosimetric advantages. Methods: The Vero treatment has unique features like no rotational or translational movements of the table during treatments, Dynamic Arc/IMRT, tracking of IR markers, limitation of Ring rotation. Accuracies of the image fusions using CBCT, orthogonal x-rays, and CT are evaluated less than ? 0.7mm with a custom-made target phantom with 18 hidden targets. 1mm margin is given to GTV to determine PTV for planning constraints considering all the uncertainties of planning computer and mechanical uncertainties of the treatment unit. Also, double-scattering proton plans with 6F to 9F beams and typical clinical parameters, multiple isocenter plans with 6 to 21 isocenters, and DA/IMRT plans are evaluated to investigate the dosimetric advantages of the DA/IMRT for complex shape of targets. Results: 3 Groups of the patients are divided: (1) Group A (complex target shape), CI's are same for IMRT, and DGI of the proton plan are better by 9.5% than that of the IMRT, (2) Group B, CI of the DA plans (1.91+/?0.4) are better than cone-based plan, while DGI of the DA plan is 4.60+/?1.1 is better than cone-based plan (5.32+/?1.4), (3) Group C (small spherical targets), CI of the DA and cone-based plans are almost the same. Conclusion: For small spherical targets, cone-based plans are superior to other 2 plans: DS proton and DA plans. For complex or irregular plans, dynamic and IMRT plans are comparable to cone-based and proton plans for complex targets.

  5. Vitamin C content of organically grown produce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organically grown produce is the fastest growing sector of fresh market sales in the U.S. While accounting for only 3% of total produce sales, it is growing by 20% per year. There has been much debate over the relative health merits of organically grown fruits and vegetables. Most consumers believ...

  6. Variations of two pools of glycogen and carbohydrate in Saccharomyces cerevisiae grown with various ethanol concentrations

    Microsoft Academic Search

    M. S. Dake; J. P. Jadhv; N. B. Patil

    2010-01-01

    Glycogen, a major reservoir of energy in Saccharomyces cerevisiae, is found to be present as soluble and membrane-bound insoluble pools. Yeast cells can store excess glycogen when grown in\\u000a media with higher concentration of sugar or when subjected to nutritional stress conditions. Saccharomyces cerevisiae NCIM-3300 was grown in media having ethanol concentrations up to 12% (v\\/v). The effects of externally

  7. Ear Cells

    NSDL National Science Digital Library

    Science Update (AAAS; )

    2008-05-06

    Spindly cells in the inner ear, called "hair" cells, are critical for both hearing and balance. Now, in a boon for research, neuro-scientists Jeffrey Corwin and Zhenqing Hu at the University of Virginia School of Medicine have finally grown and multiplied these cells in the lab.

  8. Dihydroxyacetone synthase is localized in the peroxisomal matrix of methanol-grown Hansenula polymorpha

    Microsoft Academic Search

    Anneke C. Douma; Marten Veenhuis; Wim de Koning; Melchior Evers; Wire Harder

    1985-01-01

    The subcellular localization of dihydroxyacetone synthase (DHAS) in the methylotrophic yeast Hansenula polymorpha was studied by various biochemical and immunocytochemical methods. After cell fractionation involving differential and sucrose gradient centrifugation of protoplast homogenates prepared from methanol-grown cells, DHAS cosedimented with the peroxisomal enzymes alcohol oxidase and catalase. Electron microscopy of this fraction showed that it contained mainly intact peroxisomes, whereas

  9. MBE grown iron-based nanostructures

    NASA Astrophysics Data System (ADS)

    Lok, Shu Kin

    Interest in magnetic nanostructures has increased rapidly because of their potential applications in a number of magnetic nanotechnologies such as high-density magnetic recording media, magnetic field sensors, magnetic nanoprobes for spin-polarized microscopy and cell manipulation in biomedical technology. Successful incorporation of ferromagnetic nanostructures in semiconductors may open a new area in spintronic applications. In this study, two kinds of Fe-based nanostructures were grown by the molecular beam epitaxy (MBE) technique, namely, Fe quantum dots (QDs) and Fe nanowires (NWs). For Fe QDs, a multilayer magnetic QD sample containing 5 layers of Fe QDs embedded in 6 layers of ZnS spacer was grown on a GaP(100) substrate. High resolution transmission electron microscopy (HRTEM) observations reveal that the Fe QDs are single crystalline with spherical shape of diameters around 3 to 4 nm and area density of 1.5 x 1012 cm-2 . Its zero-field cooled (ZFC) and field cooled (FC) curves measured at low field (100 Oe) show the magnetic relaxation effect with a blocking temperature around 26 K. The hysteresis loop measured at 5 K shows a coercivity of 83 Oe, confirming the slow relaxation process and coercivity enhancement attributed to the nanoparticle nature of the sample. To study the transport property of Fe QDs, a Au/ZnS/Fe-QDs/ZnS/n+-GaAs Schottky-barrier structure containing 5 layers of Fe QDs was fabricated on a n+-GaAs(100) substrate. Its current-voltage (I-V) characteristics measured from 5 to 295 K display negative differential resistance (NDR) for temperature . 50 K, which is caused by the presence of Fe QDs. The highest peak-to-valley current ratio obtained at 5 K is as high as 15:1. Staircase-like I-V characteristic was also observed at low temperature in some devices fabricated from this structure. Possible mechanisms that can account for the observed unusual I-V characteristics in this structure were discussed. Two types of self-assembled Fe NWs were grown on ZnS/GaP(100) surface under high growth/annealing temperature. The Type-A Fe NWs orient along the ZnS[110] direction with irregular shape, while the type-B Fe NWs orient along either the ZnS[180] or [810] direction with seemingly straight shape. Detailed HRTEM and selected area diffraction (SAD) studies reveal that both types were single-crystalline with their elongated axis along the Fe<100> direction family possibly due to the fact that the easy axis of Fe is along this direction. We have proposed a mean-field model to explain the slight misalignment of the type-B Fe NWs. The I-V characteristic of a single type-B Fe NW measured at room temperature displays a straight line nature corresponding to a resistivity about 2.3 x 10-7Om.

  10. 7 CFR 51.1356 - Pears grown from late blooms.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 2012-01-01 false Pears grown from late blooms. 51.1356 Section...AND STANDARDS) United States Standards for Pears for Canning Definitions § 51.1356 Pears grown from late blooms. Pears grown...

  11. 7 CFR 51.1356 - Pears grown from late blooms.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2010-01-01 2010-01-01 false Pears grown from late blooms. 51.1356 Section...AND STANDARDS) United States Standards for Pears for Canning Definitions § 51.1356 Pears grown from late blooms. Pears grown...

  12. 7 CFR 51.1356 - Pears grown from late blooms.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2011-01-01 2011-01-01 false Pears grown from late blooms. 51.1356 Section...AND STANDARDS) United States Standards for Pears for Canning Definitions § 51.1356 Pears grown from late blooms. Pears grown...

  13. 7 CFR 51.1356 - Pears grown from late blooms.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 2013-01-01 false Pears grown from late blooms. 51.1356 Section...AND STANDARDS) United States Standards for Pears for Canning Definitions § 51.1356 Pears grown from late blooms. Pears grown...

  14. 7 CFR 51.1356 - Pears grown from late blooms.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 2014-01-01 false Pears grown from late blooms. 51.1356 Section...AND STANDARDS) United States Standards for Pears for Canning Definitions § 51.1356 Pears grown from late blooms. Pears grown...

  15. A recombinant measles vaccine virus expressing wild-type glycoproteins: consequences for viral spread and cell tropism.

    PubMed

    Johnston, I C; ter Meulen, V; Schneider-Schaulies, J; Schneider-Schaulies, S

    1999-08-01

    Wild-type, lymphotropic strains of measles virus (MV) and tissue culture-adapted MV vaccine strains possess different cell tropisms. This observation has led to attempts to identify the viral receptors and to characterize the functions of the MV glycoproteins. We have functionally analyzed the interactions of MV hemagglutinin (H) and fusion (F) proteins of vaccine (Edmonston) and wild-type (WTF) strains in different combinations in transfected cells. Cell-cell fusion occurs when both Edmonston F and H proteins are expressed in HeLa or Vero cells. The expression of WTF glycoproteins in HeLa cells did not result in syncytia, yet they fused efficiently with cells of lymphocytic origin. To further investigate the role of the MV glycoproteins in virus cell entry and also the role of other viral proteins in cell tropism, we generated recombinant vaccine MVs containing one or both glycoproteins from WTF. These viruses were viable and grew similarly in lymphocytic cells. Recombinant viruses expressing the WTFH protein showed a restricted spread in HeLa cells but spread efficiently in Vero cells. Parental WTF remained restricted in both cell types. Therefore, not only differential receptor usage but also other cell-specific factors are important in determining MV cell tropism. PMID:10400788

  16. Molecule diagram from space-grown crystals

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Researchers' at Hauptman-Woodward Medical Research Institute, in Buffalo, N.Y. have analyzed the molecular structures of insulin crystals grown during Space Shuttle experiments and are unlocking the mystery of how insulin works.

  17. Nutrition of container?grown freesias

    Microsoft Academic Search

    M. Thomas; S. Matheson; M. Spurway

    1998-01-01

    As limited information is available on the nutrition of freesias an experiment was carried out to examine the influence of nutrients on foliage and corm growth, and flowering of container?grown plants. The experiment ran for 10 months using seedlings grown in a peat:sand (3:1,v:v) medium with combinations of varying levels of nitrogen (N), phosphorus (P), potassium (K), and lime. Nitrogen

  18. Microwave Heating Inactivates Shiga Toxin (Stx2) in Reconstituted Fat-Free Milk and Adversely Affects the Nutritional Value of Cell Culture Medium.

    PubMed

    Rasooly, Reuven; Hernlem, Bradley; He, Xiaohua; Friedman, Mendel

    2014-03-26

    Microwave exposure is a convenient and widely used method for defrosting, heating, and cooking numerous foods. Microwave cooking is also reported to kill pathogenic microorganisms that often contaminate food. In this study, we tested whether microwaves would inactivate the toxicity of Shiga toxin 2 (Stx2) added to 5% reconstituted fat-free milk administered to monkey kidney Vero cells. Heating of milk spiked with Stx2 in a microwave oven using a 10% duty cycle (cycle period of 30 s) for a total of 165 kJ energy or thermal heating (pasteurization), widely used to kill pathogenic bacteria, did not destroy the biological effect of the toxin in the Vero cells. However, conventional heating of milk to 95 °C for 5 min or at an increased microwave energy of 198 kJ reduced the Stx2 activity. Gel electrophoresis showed that exposure of the protein toxin to high-energy microwaves resulted in the degradation of its original structure. In addition, two independent assays showed that exposure of the cell culture medium to microwave energy of 198 kJ completely destroyed the nutritional value of the culture medium used to grow the Vero cells, possibly by damaging susceptible essential nutrients present in the medium. These observations suggest that microwave heating has the potential to destroy the Shiga toxin in liquid food. PMID:24669932

  19. The changes in Tps1 activity, trehalose content and expression of TPS1 gene in the psychrotolerant yeast Guehomyces pullulans 17-1 grown at different temperatures.

    PubMed

    Zhang, Fang; Wang, Zhi-Peng; Chi, Zhe; Raoufi, Zeinab; Abdollahi, Sajad; Chi, Zhen-Ming

    2013-03-01

    The psychrotolerant yeast Guehomyces pullulans 17-1 grows the best at 15 °C. When the yeast cells grown at 15 °C for 48 h were transferred to new medium and grown at 10, 15, and 25 °C, respectively, trehalose-6-phosphate synthase (Tps1) activity and trehalose content of the yeast cells grown at 25 °C were higher than those of the yeast cells grown at 10 and 15 °C. However, Tps1 activity and trehalose content of the yeast cells grown at 10 °C were lower than those of the yeast cells grown at 15 °C. This may suggest that trehalose synthesized by G. pullulans 17-1 only can play more important role in its adaption to high temperature than in its adaption to low temperature. After the GPTPS1 gene encoding trehalose-6-phosphate synthase was cloned from the psychrotolerant yeast, it was found that the promoter of the gene contained several stress-response elements such as C4T and AG4, indicating that the gene expression might be regulated by heat shock. It was also found that the transcriptional level of the GPTPS1 gene in the yeast cells grown at 25 °C was higher than that of the GPTPS1 gene in the yeast cells grown at 10 and 15 °C. However, the transcriptional level of the GPTPS1 gene in the yeast cells grown at 10 °C was lower than that of the yeast cells grown at 15 °C. This meant that expression of the GPTPS1 gene was constant with the changes in Tps1 activity and trehalose content of the yeast cells. PMID:23334305

  20. Some karyological observations on plants grown in space

    NASA Technical Reports Server (NTRS)

    Krikorian, A. D.; Oconnor, S. A.

    1982-01-01

    Experiments were conducted to assess whether cell division in a plant root would be affected by prolonged exposure to microgravity. Root materials from sunflower, oat, and mung bean plants grown on STS-2 and STS-3 were utilized for the experiments. It is found that all oat, sunflower, and mung seedlings showed a reduced number of cells in division as they went through their first cell division cycle on earth when compared to their ground controls. A significant number of oat, mung, and sunflower plantlets exhibited random root orientation and the lack of strictly orthotropic growth of their shoot systems in the flight samples. In addition, it is found that the mung roots were apparently least affected in terms of their cytology despite the fact that their roots were often randomly oriented.

  1. Dengue Virus Type 1 Nonstructural Glycoprotein NS1 Is Secreted from Mammalian Cells as a Soluble Hexamer in a Glycosylation-Dependent Fashion

    Microsoft Academic Search

    MARIE FLAMAND; FRANCOISE MEGRET; MAGALI MATHIEU; JEAN LEPAULT; FELIX A. REY; VINCENT DEUBEL; Biochimie Structurales

    1999-01-01

    Nonstructural glycoprotein NS1, specified by dengue virus type 1 (Den-1), is secreted from infected green monkey kidney (Vero) cells in a major soluble form characterized by biochemical and biophysical means as a unique hexameric species. This noncovalently bound oligomer is formed by three dimeric subunits and has a molecular mass of 310 kDa and a Stokes radius of 64.4 Å.

  2. Cells

    NSDL National Science Digital Library

    Mrs. McNees

    2010-09-28

    Students use websites to review about cells and cell processes. The Cell Look inside a cell The Virtual Cell Another inside view of a cell. Click on the worksheet. Cells of the body Look inside cells of the body Cells Flash cards Practice cell parts with functions. Cell Concentration Play concentration matching game. Cell Differentiation Movie Watch how cells change as an organism develops. Cell Organelle Table Review Cell Organelles Inside a Cell Look Inside a Cell Nobel Prize Educational Games Play games while learning about ...

  3. Human Colon Cancer Cells Cultivated in Space

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Within five days, bioreactor cultivated human colon cancer cells (shown) grown in Microgravity on the STS-70 mission in 1995, had grown 30 times the volume of the control specimens on Earth. The samples grown in space had a higher level of cellular organization and specialization. Because they more closely resemble tumors found in the body, microgravity grown cell cultures are ideal for research purposes.

  4. Cells infected with herpes simplex virus 1 export to uninfected cells exosomes containing STING, viral mRNAs, and microRNAs.

    PubMed

    Kalamvoki, Maria; Du, Te; Roizman, Bernard

    2014-11-18

    STING (stimulator of IFN genes) activates the IFN-dependent innate immune response to infection on sensing the presence of DNA in cytosol. The quantity of STING accumulating in cultured cells varies; it is relatively high in some cell lines [e.g., HEp-2, human embryonic lung fibroblasts (HEL), and HeLa] and low in others (e.g., Vero cells). In a preceding publication we reported that STING was stable in four cell lines infected with herpes simplex virus 1 and that it was actively stabilized in at least two cell lines derived from human cancers. In this report we show that STING is exported from HEp-2 cells to Vero cells along with virions, viral mRNAs, microRNAs, and the exosome marker protein CD9. The virions and exosomes copurified. The quantity of STING and CD9 exported from one cell line to another was inoculum-size-dependent and reflected the levels of STING and CD9 accumulating in the cells in which the virus inoculum was made. The export of STING, an innate immune sensor, and of viral mRNAs whose major role may be in silencing viral genes in latently infected neurons, suggests that the virus has evolved mechanisms that curtail rather than foster the spread of infection under certain conditions. PMID:25368198

  5. Using Speckle Dynamics for Comparison of the Metabolic Activity of Different Cell Cultures

    NASA Astrophysics Data System (ADS)

    Vladimirov, A. P.; Malygin, A. S.; Mikhailova, Yu. A.; Borodin, E. M.; Bakharev, A. A.; Poryvaeva, A. P.

    2015-01-01

    The dynamics of speckles in the image plane of a monolayer of cells cultivated on a glass substrate has been recorded. Cell cultures HEL-3, L-41, and Vero were selected as the objects of research. The digitized value of the radiation intensity I in one pixel and the parameter ? characterizing the change in the intensity distribution on an 10 × 10 pixel area was recorded for 24 hours. The multiple determinacy coefficient of three cell cultures, which was obtained from the time dependences of ?, was equal to 0.94.

  6. Changes in fatty acids, amino acids and carbon\\/nitrogen biomass during nitrogen starvation of ammonium- and nitrate-grown Isochrysis galbana

    Microsoft Academic Search

    K. J. Flynn; J. L. Garrido; M. Zapata; H. Öpik; C. R. Hipkin

    1992-01-01

    Growth of cells ofIsochrysis galbana with either nitrate or ammonium as the N-source, and the effects of subsequent N-starvation of these cells, were compared.\\u000a During exponential N-sufficient growth nitrate-grown cells had double the fatty acid content of the ammonium-grown cells but\\u000a lower concentrations of a few amino acids. Following resuspension in N-free medium the fatty acid content of the ammonium-grown

  7. Single-fraction spine SBRT end-to-end testing on TomoTherapy, Vero, TrueBeam, and CyberKnife treatment platforms using a novel anthropomorphic phantom.

    PubMed

    Gallo, John J; Kaufman, Isaac; Powell, Rachel; Pandya, Shalini; Somnay, Archana; Bossenberger, Todd; Ramirez, Ezequiel; Reynolds, Robert; Solberg, Timothy; Burmeister, Jay

    2015-01-01

    Spine SBRT involves the delivery of very high doses of radiation to targets adjacent to the spinal cord and is most commonly delivered in a single fraction. Highly conformal planning and accurate delivery of such plans is imperative for successful treatment without catastrophic adverse effects. End-to-end testing is an important practice for evaluating the entire treatment process from simulation through treatment delivery. We performed end-to-end testing for a set of representative spine targets planned and delivered using four different treatment planning systems (TPSs) and delivery systems to evaluate the various capabilities of each. An anthropomorphic E2E SBRT phantom was simulated and treated on each system to evaluate agreement between measured and calculated doses. The phantom accepts ion chambers in the thoracic region and radiochromic film in the lumbar region. Four representative targets were developed within each region (thoracic and lumbar) to represent different presentations of spinal metastases and planned according to RTOG 0631 constraints. Plans were created using the TomoTherapy TPS for delivery using the Hi·Art system, the iPlan TPS for delivery using the Vero system, the Eclipse TPS for delivery using the TrueBeam system in both flattened and flattening filter free (FFF), and the MultiPlan TPS for delivery using the CyberKnife system. Delivered doses were measured using a 0.007 cm3 ion chamber in the thoracic region and EBT3 GAFCHROMIC film in the lumbar region. Films were scanned and analyzed using an Epson Expression 10000XL flatbed scanner in conjunction with FilmQAPro2013. All treatment platforms met all dose constraints required by RTOG 0631. Ion chamber measurements in the thoracic targets delivered an overall average difference of 1.5%. Specifically, measurements agreed with the TPS to within 2.2%, 3.2%, 1.4%, 3.1%, and 3.0% for all three measureable cases on TomoTherapy, Vero, TrueBeam (FFF), TrueBeam (flattened), and CyberKnife, respectively. Film measurements for the lumbar targets resulted in average global gamma index passing rates of 100% at 3%/3 mm, 96.9% at 2%/2mm, and 61.8% at 1%/1 mm, with a 10% minimum threshold for all plans on all platforms. Local gamma analysis was also performed with similar results. While gamma passing rates were consistently accurate across all platforms through 2%/2 mm, treatment beam-on delivery times varied greatly between each platform with TrueBeam FFF being shortest, averaging 4.4 min, TrueBeam using flattened beam at 9.5 min, TomoTherapy at 30.5 min, Vero at 19 min, and CyberKnife at 46.0 min. In spite of the complexity of the representative targets and their proximity to the spinal cord, all treatment platforms were able to create plans meeting all RTOG 0631 dose constraints and produced exceptional agreement between calculated and measured doses. However, there were differences in the plan characteristics and significant differences in the beam-on delivery time between platforms. Thus, clinical judgment is required for each particular case to determine most appropriate treatment planning/delivery platform. PMID:25679169

  8. Morphology of fibroblasts grown on substrates formed by dielectrophoretically aligned carbon nanotubes

    PubMed Central

    Yuen, Felix L.-Y.; Zak, Gene; Waldman, Stephen D.

    2007-01-01

    Multiwall carbon nanotube templates formed on the surfaces of planar interdigitated microelectrode arrays by means of AC electric field-guided assembly are being explored as potential substrates for tissue engineering. The objective of the present study is to examine whether surface patterns of aligned multiwall carbon nanotubes can have an effect on cell growth, morphology, and alignment. Bovine fibroblasts grown on aligned carbon nanotubes for a period of 2 weeks were found to have raised bodies and pronounced cell extensions for anchoring themselves to the substrate similar to that of the cells found in native tissues. On the other hand, cells grown on various control surfaces had a flat, circular morphology. The cell cultures were visualized by means of SEM imaging and the resulting morphologies were statistically analyzed and compared. PMID:19002836

  9. Unstable Expression and Thermal Instability of a Species-Specific Cell Surface Epitope Associated with a 66-Kilodalton Antigen Recognized by Monoclonal Antibody EM7G1 within Serotypes of Listeria monocytogenes Grown in Nonselective and Selective Broths

    Microsoft Academic Search

    RAMAKRISHNA NANNAPANENI; ROBERT STORY; ARUN K. BHUNIA; MICHAEL G. JOHNSON

    1998-01-01

    Conditions that resulted in unstable expression and heat instability of a cell surface epitope associated with a 66-kDa antigen in Listeria monocytogenes serotypes were identified with the probe monoclonal antibody (MAb) EM-7G1 in an enzyme-linked immunosorbent assay. This epitope appeared to be absent in three serotypes (serotypes 3b, 4a, and 4c), which did not react with MAb EM-7G1 irrespective of

  10. Automorphogenesis and gravitropism of plant seedlings grown under microgravity conditions.

    PubMed

    Hoson, T; Saiki, M; Kamisaka, S; Yamashita, M

    2001-01-01

    Plant seedlings exhibit automorphogenesis on clinostats. The occurrence of automorphogenesis was confirmed under microgravity in Space Shuttle STS-95 flight. Rice coleoptiles showed an inclination toward the caryopsis in the basal region and a spontaneous curvature in the same adaxial direction in the elongating region both on a three-dimensional (3-D) clinostat and in space. Both rice roots and Arabidopsis hypocotyls also showed a similar morphology in space and on the 3-D clinostat. In rice coleoptiles, the mechanisms inducing such an automorphic curvature were studied. The faster-expanding convex side of rice coleoptiles showed a higher extensibility of the cell wall than the opposite side. Also, in the convex side, the cell wall thickness was smaller, the turnover of the matrix polysaccharides was more active, and the microtubules oriented more transversely than the concave side, and these differences appear to be causes of the curvature. When rice coleoptiles grown on the 3-D clinostat were placed horizontally, the gravitropic curvature was delayed as compared with control coleoptiles. In clinostatted coleoptiles, the corresponding suppression of the amyloplast development was also observed. Similar results were obtained in Arabidopsis hypocotyls. Thus, the induction of automorphogenesis and a concomitant decrease in graviresponsiveness occurred in plant shoots grown under microgravity conditions. PMID:11596636

  11. Graphene Films Grown on Insulating Substrates

    NASA Astrophysics Data System (ADS)

    Samsonau, Siarhei V.; Exarhos, Annemarie L.; Turk, Michael E.; Cai, Jing; Deshko, Yury; Gorokhovsky, Anshel A.; Kikkawa, Jay M.; Zaitsev, Alexander M.

    2011-03-01

    We report a method of direct CVD growth of carbon films on quartz substrates. The films are grown at temperatures from 650 to 1200 ^oC in a graphite container filled with methane. Films grown at 1200 ^oC reveal clear G and 2D Raman bands characteristic of graphene. A combination of Raman, absorption and electrical measurements allows us to conclude that carbon films grown by this method are polycrystalline graphene, large areas of which may be composed of single carbon layer. Sheet resistivity of these graphene films is low enough to make them interesting objects for electronic applications. Advantages of our synthetic approach include simplicity and the ability to deposit films on any insulating substrate, which can stand temperature of at least 650 ^oC. Thus far, no factors limiting the area of deposition and uniformity of the deposited graphene films have been identified.

  12. Stability of Detached Grown Germanium Single Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Volz, M. P.; Cobb, S. D.; Vujisic, L.; Szofran, F. R.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Detachment of the melt meniscus from the crucible during semiconductor Bridgman growth experiments has been observed in recent years, especially under microgravity experiments. Under earth conditions, the hydrostatic pressure counteracts the mechanism, whereby it is more difficult to achieve detached Bridgman growth. Attempts to get stable detached growth under terrestrial conditions have been discussed in the literature and have been the subject of recent experiments in our own group. The advantage of crystals grown without wall contact is obvious: In general, they possess a higher crystal quality than conventional Bridgman grown crystals with wall contact. However, due to the interaction of different parameters such as the wetting behavior of the melt with the crucible, and the dependence of the growth angle with the shape of the melt meniscus, the mechanism leading to detachment is very complicated and not completely understood. We have grown several doped and undoped Germanium crystals with the detached Bridgman and the normal Bridgman growth technique. Pyrolytic boron nitride containers were used for all growth experiments. In the detached grown crystals the typical gap thickness between the pBN crucible and the crystal is in the range of 10 to 100 micrometers, which was determined by performing profilometer measurements. Etch pit density measurements were also performed and a comparison between detached and attached grown crystals will be given. An interesting feature was detected on the surface of a detached grown crystal. Strong surface striations with an average axial distance of 0.5 mm were observed around the whole circumference. The maximum fluctuation of the gap thickness is in the range of 5-10 micrometers. These variations of the detached gap along the crystal axis can be explained by a kind of stiction of the melt/crucible interface and thus by a variation of the meniscus shape. This phenomenon leading to the fluctuation of the gap thickness will be discussed in detail.

  13. Stability of Detached Grown Germanium Single Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Volz, M. P.; Cobb, S. D.; Motakef, S.; Szofran, F. R.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Detachment of the melt meniscus from the crucible during semiconductor Bridgman growth experiments has been observed in recent years especially, under microgravity experiments. Under earth conditions, the hydrostatic pressure counteracts the mechanism, whereby it is more difficult to achieve detached Bridgman growth. Attempts to get stable detached growth under terrestrial conditions have been discussed in the literature and have been the subject of recent experiments in our own group. The advantage of crystals grown without wall contact is obvious: In general, they possess a higher crystal quality than conventional Bridgman grown crystals with wall contact. However, due to the interaction of different parameters such as the wetting behavior of the melt with the crucible, and the dependence of the growth angle with the shape of the melt meniscus, the mechanism leading to detachment is very complicated and not completely understood. We have grown several doped and undoped Germanium crystals with the detached Bridgman and the normal Bridgman growth technique. Pyrolytic boron nitride containers were used for all growth experiments. In the detached grown crystals the typical gap thickness between the pBN crucible and the crystal is in the range of 10 to 100 microns, which was determined by performing profilometer measurements. Etch pit density measurements were also performed and a comparison between detached and attached grown crystals will be given. An interesting feature was detected on the surface of a detached grown crystal. Strong surface striations with an average axial distance of 0.5mm were observed around the whole circumference. The maximum fluctuation of the gap thickness is in the range of 5-10 microns. These variations of the detached gap along the crystal axis can be explained by a kind of stiction of the melt/crucible interface and thus by a variation of the meniscus shape. This phenomenon leading to the fluctuation of the gap thickness will be discussed in detail.

  14. Ion implanted epitaxially grown ZnSe

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The epitaxial growth of ZnSe on (100) Ge using the close-spaced transport process is described. Substrate temperature of 575 C and source temperatures of 675 C yield 10 micron, single crystal layers in 10 hours. The Ge substrates provides a nonreplenishable chemical transport agent and the epitaxial layer thickness is limited to approximately 10 microns. Grown epitaxial layers show excellent photoluminescence structure at 77 K. Grown layers exhibit high resistivity, and annealing in Zn vapor at 575 C reduces the resistivity to 10-100 ohms-cm. Zinc vapor annealing quenches the visible photoluminescence.

  15. Molecule diagram from earth-grown crystals

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Like many chemicals in the body, the three-dimensional structure of insulin is extremely complex. When grown on the ground, insulin crystals do not grow as large or as ordered as researchers desire--obscuring the blueprint of the insulin molecules.

  16. AFLATOXIN CONTAMINATION OF COMMERCIALLY GROWN TRANSGENIC

    E-print Network

    Cotty, Peter J.

    108 AFLATOXIN CONTAMINATION OF COMMERCIALLY GROWN TRANSGENIC BT COTTONSEED P.J. Cotty and C. Bock cotton may have reduced susceptibility to aflatoxin contamination as a result of pink bollworm resistance) from one highly contaminated (>6,000 ppb aflatoxin B1) Bt seed lot indicated that most contamination

  17. Efflux Of Nitrate From Hydroponically Grown Wheat

    NASA Technical Reports Server (NTRS)

    Huffaker, R. C.; Aslam, M.; Ward, M. R.

    1992-01-01

    Report describes experiments to measure influx, and efflux of nitrate from hydroponically grown wheat seedlings. Ratio between efflux and influx greater in darkness than in light; increased with concentration of nitrate in nutrient solution. On basis of experiments, authors suggest nutrient solution optimized at lowest possible concentration of nitrate.

  18. Rice Plants Grown With and Without Endophytes

    USGS Multimedia Gallery

    These rice plants show the difference in growth of rice plants exposed to salt when grown with and without endophytes, which are mutually beneficial microscopic fungi that live in most plants. The plant on the left was colonized with a fungi that made it salt-tolerant, but it wasn't exposed to ...

  19. Grown-ups Ought To Know Better.

    ERIC Educational Resources Information Center

    Brightman, Samuel C.

    Among the articles by Sam Brightman collected in this volume from the newsletter, "Adult & Continuing Education Today (ACET)" are the following: "Grown-Ups Ought to Know Better"; "Adult Education: The Only Sure Factor Is Growth"; "Adult Education Important in This Election Year"; "Will Nursery School External Degree Programs Come Next?";…

  20. Vapor-grown atomic filaments of graphite

    Microsoft Academic Search

    F. Okuyama; T. Hayashi; M. Kawasaki; K. Ibe

    2000-01-01

    Field emission transmission electron microscopy has revealed the presence of atomic filaments extending from the open edge of a graphite cage formed in a glow-discharge plasma. The filaments are vapor grown, presenting complicated deformations such as curling, waving, and looping in the free space. The filaments correspond well to one carbon atom in diameter, strongly indicating that they are linear

  1. Transport studies on CVD-grown graphene

    E-print Network

    Huntley, Miriam Hanna

    2009-01-01

    In this thesis, we report transport studies performed on CVD-grown graphene. We perform resistivity and hall measurements on a large-area sample at 4' K. We measure the carrier mobility of the sample and find it to be on ...

  2. Dynamic Contrast-Enhanced Magnetic Resonance Imaging Rapidly Indicates Vessel Regression in Human Squamous Cell Carcinomas Grown in Nude Mice Caused by VEGF Receptor 2 Blockade with DC1011

    PubMed Central

    Kiessling, Fabian; Farhan, Nabeel; Lichy, Matthias P; Vosseler, Silvia; Heilmann, Melanie; Krix, Martin; Bohlen, Peter; Miller, Dan W; Mueller, Margareta M; Semmler, Wolfhard; Fusenig, Norbert E; Stefan, Delorme

    2004-01-01

    Abstract The purpose of our study was the investigation of early changes in tumor vascularization during antiangiogenic therapy with the vascular endothelial growth factor (VEGF) receptor 2 antibody (DC101) using dynamic contrast-enhanced magnetic resonance imaging (DCE MRI). Subcutaneous heterotransplants of human skin squamous cell carcinomas in nude mice were treated with DC101. Animals were examined before and repeatedly during 2 weeks of antiangiogenic treatment using Gd-DTPA-enhanced dynamic T1-weighted MRI. With a two-compartment model, dynamic data were parameterized in “amplitude” (increase of signal intensity relative to precontrast value) and kep (exchange rate constant). Data obtained by MRI were validated by parallel examinations of histological sections immunostained for blood vessels (CD31). Already 2 days after the first DC101 application, a decrease of tumor vascularization was observed, which preceded a reduction of tumor volume. The difference between treated tumors and controls became prominent after 4 days, when amplitudes of treated tumors were decreased by 61% (P = .02). In line with change of microvessel density, the decrease in amplitudes was most pronounced in tumor centers. On day 7, the mean tumor volumes of treated (153 ± 843 mm3) and control animals (596 ± 384 mm3) were significantly different (P = .03). After 14 days, treated tumors showed further growth reduction (83 ± 93 mm3), whereas untreated tumors (1208 ± 822 mm3) continued to increase (P = .02). Our data underline the efficacy of DC101 as antiangiogenic treatment in human squamous cell carcinoma xenografts in nude mice and indicate DCE MRI as a valuable tool for early detection of treatment effects before changes in tumor volume become apparent. PMID:15153333

  3. Auxin represses stomatal development in dark-grown seedlings via Aux/IAA proteins.

    PubMed

    Balcerowicz, Martin; Ranjan, Aashish; Rupprecht, Laura; Fiene, Gabriele; Hoecker, Ute

    2014-08-01

    Stomatal development is tightly regulated through internal and external factors that are integrated by a complex signalling network. Light represents an external factor that strongly promotes stomata formation. Here, we show that auxin-resistant aux/iaa mutants, e.g. axr3-1, exhibit a de-repression of stomata differentiation in dark-grown seedlings. The higher stomatal index in dark-grown axr3-1 mutants when compared with the wild type is due to increased cell division in the stomatal lineage. Excessive stomata in dark-grown seedlings were also observed in mutants defective in auxin biosynthesis or auxin perception and in seedlings treated with the polar auxin transport inhibitor NPA. Consistent with these findings, exogenous auxin repressed stomata formation in light-grown seedlings. Taken together, these results indicate that auxin is a negative regulator of stomatal development in dark-grown seedlings. Epistasis analysis revealed that axr3-1 acts genetically upstream of the bHLH transcription factors SPCH, MUTE and FAMA, as well as the YDA MAP kinase cascade, but in parallel with the repressor of photomorphogenesis COP1 and the receptor-like protein TMM. The effect of exogenous auxin required the ER family of leucine-rich repeat receptor-like kinases, suggesting that auxin acts at least in part through the ER family. Expression of axr3-1 in the stomatal lineage was insufficient to alter the stomatal index, implying that cell-cell communication is necessary to mediate the effect of auxin. In summary, our results show that auxin signalling contributes to the suppression of stomatal differentiation observed in dark-grown seedlings. PMID:25063454

  4. [Safety assessment of stevia rebaudiana bertoni grown in southeastern Mexico as food sweetener].

    PubMed

    Aranda-González, Irma; Barbosa-Martín, Enrique; Toraya-Avilés, Rocío; Segura-Campos, Maira; Moguel-Ordoñez, Yolanda; Betancur-Ancona, David

    2014-01-01

    Stevia rebaudiana leaves and their glycosides have been recently and significantly used so important as sweeteners. However, it has been reported an antihyperglycemic effect of the extract and a glycoside. The aim of this study was to quantify S. rebaudiana glycosides, assess cytotoxicity of the extract and its acute and chronic effect on blood glucose in animal models and in human. The glycosides of the Morita II and Criolla extract were quantified by HPLC, using a C18 column (250 mm x 4.6 mm and particle size of 5 uM) with UV detection at 210 nm, mobile phase of acetonitrile/sodium phosphate buffer 10 mmol/L, pH 2.6 (32:68 v/v). Cytotoxicity study was performed in Vero cells, whereas an intraperitoneal glucose tolerance test (IPGTT) and a chronic consumption assay (4 weeks) were executed in an animal model of diabetes; finally the glycemic index (G.I.) was determined in healthy individuals. The glycoside content is higher in the Morita variety II although both had a CC50 >300 ?g/mL. The areas under the curve of the IPGTT and fasting glucose of the animals were not significantly different (p> 0.05) and the I.G. extract was 11.11 %, which classifies the extract as low I.G. The extract of S. rebaudiana Morita II has a low glycemic index and, in the doses tested, is not cytotoxic nor has acute or chronic effect on blood sugar, which makes it a safe sweetener. PMID:25238836

  5. Sulfated proteoglycan synthesis by confluent cultures of rabbit costal chondrocytes grown in the presence of fibroblast growth factor

    PubMed Central

    1985-01-01

    We examined the effect of fibroblast growth factor (FGF) on proteoglycan synthesis by rabbit costal chondrocyte cultures maintained on plastic tissue culture dishes. Low density rabbit costal chondrocyte cultures grown in the absence of FGF gave rise at confluency to a heterogeneous cell population composed of fibroblastic cells and poorly differentiated chondrocytes. When similar cultures were grown in the presence of FGF, the confluent cultures organized into a homogenous cartilage-like tissue composed of rounded cells surrounded by a refractile matrix. The cell ultrastructure and that of the pericellular matrix were similar to those seen in vivo. The expression of the cartilage phenotype in confluent chondrocyte cultures grown from the sparse stage in the presence vs. absence of FGF was reflected by a fivefold increase in the rate of incorporation of [35S]sulfate into proteoglycans. These FGF effects were only observed when FGF was present during the cell logarithmic growth phase, but not when it was added after chondrocyte cultures became confluent. High molecular weight, chondroitin sulfate proteoglycans synthesized by confluent chondrocyte cultures grown in the presence of FGF were slightly larger in size than that produced by confluent cultures grown in the absence of FGF. The major sulfated glycosaminoglycans associated with low molecular weight proteoglycan in FGF-exposed cultures were chondroitin sulfate, while in cultures not exposed to FGF they were chondroitin sulfate and dermatan sulfate. Regardless of whether or not cells were grown in the presence or absence of FGF, the 6S/4S disaccharide ratio of chondroitin sulfate chains associated with high and low molecular weight proteoglycans synthesized by confluent cultures was the same. These results provide evidence that when low density chondrocyte cultures maintained on plastic tissue culture dishes are grown in the presence of FGF, it results in a stimulation of the expression and stabilization of the chondrocyte phenotype once cultures become confluent. PMID:3968172

  6. In vitro inactivation of the rabies virus by ascorbic acid

    Microsoft Academic Search

    Shampur Narayan Madhusudana; Ranjini Shamsundar; Saraswati Seetharaman

    2004-01-01

    Objective: The current recommended inactivating agent for the rabies virus, beta propiolactone (BPL) is very expensive and potentially carcinogenic. There is a need to evaluate alternative chemicals, which will inactivate the virus without affecting its antigenicity. In this study the effect of ascorbic acid on the infectivity of the rabies virus has been investigated.Method: Vero cell grown fixed rabies virus

  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. PMID:24319380

  8. Characterization of Cellulolytic Bacterial Cultures Grown in Different Substrates

    PubMed Central

    Alshelmani, Mohamed Idris; Loh, Teck Chwen; Foo, Hooi Ling; 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. PMID:24319380

  9. Learning about Cancer by Studying Stem Cells

    MedlinePLUS

    ... Science Home Page Learning About Cancer by Studying Stem Cells By Sharon Reynolds Posted January 8, 2014 Normally, ... of them are exploring the process by studying stem cells. Modeling Early Pancreatic Cancer Pancreatic cancer cells grown ...

  10. 76 FR 16323 - Irish Potatoes Grown in Washington; Continuance Referendum

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-23

    ...AMS-FV-11-0010; FV11-946-1 CR] Irish Potatoes Grown in Washington; Continuance...conducted among eligible Washington potato growers to determine whether they...order regulating the handling of Irish potatoes grown in Washington....

  11. Three distinct quinoprotein alcohol dehydrogenases are expressed when Pseudomonas putida is grown on different alcohols.

    PubMed Central

    Toyama, H; Fujii, A; Matsushita, K; Shinagawa, E; Ameyama, M; Adachi, O

    1995-01-01

    A bacterial strain that can utilize several kinds of alcohols as its sole carbon and energy sources was isolated from soil and tentatively identified as Pseudomonas putida HK5. Three distinct dye-linked alcohol dehydrogenases (ADHs), each of which contained the prosthetic group pyrroloquinoline quinone (PQQ), were formed in the soluble fractions of this strain grown on different alcohols. ADH I was formed most abundantly in the cells grown on ethanol and was similar to the quinoprotein ADH reported for P. putida (H. Görisch and M. Rupp, Antonie Leeuwenhoek 56:35-45, 1989) except for its isoelectric point. The other two ADHs, ADH IIB and ADH IIG, were formed separately in the cells grown on 1-butanol and 1,2-propanediol, respectively. Both of these enzymes contained heme c in addition to PQQ and functioned as quinohemoprotein dehydrogenases. Potassium ferricyanide was an available electron acceptor for ADHs IIB and IIG but not for ADH I. The molecular weights were estimated to be 69,000 for ADH IIB and 72,000 for ADH IIG, and both enzymes were shown to be monomers. Antibodies raised against each of the purified ADHs could distinguish the ADHs from one another. Immunoblot analysis showed that ADH I was detected in cells grown on each alcohol tested, but ethanol was the most effective inducer. ADH IIB was formed in the cells grown on alcohols of medium chain length and also on 1,3-butanediol. Induction of ADH IIG was restricted to 1,2-propanediol or glycerol, of which the former alcohol was more effective. These results from immunoblot analysis correlated well with the substrate specificities of the respective enzymes. Thus, three distinct quinoprotein ADHs were shown to be synthesized by a single bacterium under different growth conditions. PMID:7730276

  12. Counting molecular-beam grown graphene layers

    SciTech Connect

    Plaut, Annette S. [School of Physics, University of Exeter, Exeter EX4 4QL (United Kingdom)] [School of Physics, University of Exeter, Exeter EX4 4QL (United Kingdom); Wurstbauer, Ulrich [Department of Physics, Columbia University, New York, New York 10027 (United States)] [Department of Physics, Columbia University, New York, New York 10027 (United States); Pinczuk, Aron [Department of Physics, Columbia University, New York, New York 10027 (United States) [Department of Physics, Columbia University, New York, New York 10027 (United States); Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States); Garcia, Jorge M. [MBE Lab, IMM-Instituto de Microelectronica de Madrid (CNM-CSIC), Madrid, E-28760 (Spain)] [MBE Lab, IMM-Instituto de Microelectronica de Madrid (CNM-CSIC), Madrid, E-28760 (Spain); Pfeiffer, Loren N. [Electrical Engineering Department, Princeton University, New Jersey 08544 (United States)] [Electrical Engineering Department, Princeton University, New Jersey 08544 (United States)

    2013-06-17

    We have used the ratio of the integrated intensity of graphene's Raman G peak to that of the silicon substrate's first-order optical phonon peak, accurately to determine the number of graphene layers across our molecular-beam (MB) grown graphene films. We find that these results agree well both, with those from our own exfoliated single and few-layer graphene flakes, and with the results of Koh et al.[ACS Nano 5, 269 (2011)]. We hence distinguish regions of single-, bi-, tri-, four-layer, etc., graphene, consecutively, as we scan coarsely across our MB-grown graphene. This is the first, but crucial, step to being able to grow, by such molecular-beam-techniques, a specified number of large-area graphene layers, to order.

  13. Mineral composition of organically grown tomato

    NASA Astrophysics Data System (ADS)

    Ghambashidze, Giorgi

    2014-05-01

    In recent years, consumer concerns on environmental and health issues related to food products have increased and, as a result, the demand for organically grown production has grown. Results indicate that consumers concerned about healthy diet and environmental degradation are the most likely to buy organic food, and are willing to pay a high premium. Therefore, it is important to ensure the quality of the produce, especially for highly consumed products. The tomato (Lycopersicon esculentum) is one of the most widely consumed fresh vegetables in the world. It is also widely used by the food industries as a raw material for the production of derived products such as purees or ketchup. Consequently, many investigations have addressed the impact of plant nutrition on the quality of tomato fruit. The concentrations of minerals (P, Na, K, Ca and Mg) and trace elements (Cu, Zn and Mn) were determined in tomatoes grown organically in East Georgia, Marneuli District. The contents of minerals and Mn seem to be in the range as shown in literature. Cu and Zn were found in considerably high amounts in comparison to maximum permissible values established in Georgia. Some correlations were observed between the minerals and trace elements studied. K and Mg were strongly correlated with Cu and Zn. Statistically significant difference have shown also P, K and Mg based between period of sampling.

  14. Electrical currents through full-grown and maturing Xenopus oocytes.

    PubMed Central

    Robinson, K R

    1979-01-01

    An extracellular vibrating electrode was used to map the current pattern around Xenopus laevis oocytes. Current was found to enter the animal hemisphere and leave the vegetal hemisphere; in fully grown oocytes from which the follicle cells had been removed, the maximal current density was about 1 microamperemeter/cm2. This current decreased to nearly zero in response to progesterone and several other maturation-producing agents. In the case of progesterone, the decline began within a few minutes of the addition of the hormone and proceeded with a half-time of about 20 min. An analysis of the effects on the current of the removal or addition of various ions and drugs led to the inference that the major current-carrying ion was chloride and that the chloride permeability was controlled by calcium. PMID:284407

  15. Lipid accumulation by Rhodococcus rhodochrous grown on glucose.

    PubMed

    Shields-Menard, Sara A; Amirsadeghi, Marta; Sukhbaatar, Badamkhand; Revellame, Emmanuel; Hernandez, Rafael; Donaldson, Janet R; French, W Todd

    2015-05-01

    Biodiesel is an alternative fuel made from costly vegetable oil feedstocks. Some microorganisms can accumulate lipids when nutrients are limited and carbon is in excess. Rhodococcus rhodochrous is a gram-positive bacterium most often used in bioremediation or acrylamide production. The purpose of this study was to investigate and characterize the lipid accumulation capabilities of R. rhodochrous. Shake flasks and a large-scale fermentation were used to cultivate R. rhodochrous in varying concentrations of glucose. R. rhodochrous achieved almost 50 % of dry cell mass as lipid when grown in 20 g/L of glucose. Wax esters and triglycerides were identified in R. rhodochrous lipid extract. The transesterified extractables of R. rhodochrous consisted of mostly palmitic (35 %) and oleic (42 %) acid methyl esters. This study shows R. rhodochrous to be an oleaginous bacterium with potential for application in alternative fuels. PMID:25656153

  16. Hydrothermally grown nanostructured WO films and their electrochromic characteristics

    E-print Network

    Demir, Hilmi Volkan

    Hydrothermally grown nanostructured WO 3 films and their electrochromic characteristics.1088/0022-3727/43/28/285501 Hydrothermally grown nanostructured WO3 films and their electrochromic characteristics Zhihui Jiao1 , Xiao Wei and their electrochromic characteristics. Plate-like monoclinic WO3 nanostructures were grown directly on fluorine

  17. Chemical composition of sewage-grown Spirulina platensis

    Microsoft Academic Search

    P. N. Saxena; M. R. Ahmad; R. Shyam; P. S. Misra

    1982-01-01

    Summary Spirulina platensis has been grown in an outdoor pilot production unit, with an exposed surface area of 450 m2, on a medium consisting of raw domestic sewage supplemented with sodium bicarbonate and nitrate or urea fertilizer. The chemical composition and yield of the biomass grown on sewage-nitrate was comparable to that grown on synthetic medium. The protein content was

  18. Time Resolved Photoluminescence of Si-doped High Al Mole Fraction AlGaN Epilayers Grown by Plasma-Enhanced Molecular Beam Epitaxy

    E-print Network

    Cartwright, Alexander N.

    in these epilayers. EXPERIMENTAL DETAILS The Si-doped AlGaN epilayers were grown in a turbomolecular Varian Gen II MBE system which uses standard effusion cells for the group III elements. An EPI RF plasma source

  19. Akabane Virus Utilizes Alternative Endocytic Pathways to Entry into Mammalian Cell Lines

    PubMed Central

    BANGPHOOMI, Norasuthi; TAKENAKA-UEMA, Akiko; SUGI, Tatsuki; KATO, Kentaro; AKASHI, Hiroomi; HORIMOTO, Taisuke

    2014-01-01

    ABSTRACT The entry mechanisms of Akabane virus (AKAV), Bunyaviridae family, have not yet been determined. In this study, chemical inhibitors were used to analyze endocytic mechanisms during AKAV infection of mammalian cell lines. The analyses using drug treatments followed by quantitative measurement of viral RNA and N protein revealed that AKAV enters non-bovine-derived cell lines (Vero, HmLu-1 and BHK cells) in a manner indicative of clathrin endocytosis. By contrast, AKAV infection in bovine-derived cell lines (LB9.K and MDBK cells) is independent of this pathway. Further analyses indicated that AKAV entry into bovine cell lines involves a non-clathrin, non-caveolae endocytic pathway that is dependent on dynamin. We conclude that although both cell types require a low pH for AKAV penetration, AKAV utilizes alternative entry pathways into mammalian cell lines. PMID:25056673

  20. Akabane virus utilizes alternative endocytic pathways to entry into mammalian cell lines.

    PubMed

    Bangphoomi, Norasuthi; Takenaka-Uema, Akiko; Sugi, Tatsuki; Kato, Kentaro; Akashi, Hiroomi; Horimoto, Taisuke

    2014-11-01

    The entry mechanisms of Akabane virus (AKAV), Bunyaviridae family, have not yet been determined. In this study, chemical inhibitors were used to analyze endocytic mechanisms during AKAV infection of mammalian cell lines. The analyses using drug treatments followed by quantitative measurement of viral RNA and N protein revealed that AKAV enters non-bovine-derived cell lines (Vero, HmLu-1 and BHK cells) in a manner indicative of clathrin endocytosis. By contrast, AKAV infection in bovine-derived cell lines (LB9.K and MDBK cells) is independent of this pathway. Further analyses indicated that AKAV entry into bovine cell lines involves a non-clathrin, non-caveolae endocytic pathway that is dependent on dynamin. We conclude that although both cell types require a low pH for AKAV penetration, AKAV utilizes alternative entry pathways into mammalian cell lines. PMID:25056673

  1. Cell lines that support replication of a novel herpes simplex virus 1 U{sub L}31 deletion mutant can properly target U{sub L}34 protein to the nuclear rim in the absence of U{sub L}31

    SciTech Connect

    Liang Li [Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853 (United States); Tanaka, Michiko [Department of Virology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550 (Japan); Kawaguchi, Yasushi [Department of Virology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550 (Japan); Baines, Joel D. [Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853 (United States)]. E-mail: jdb11@cornell.edu

    2004-11-10

    Previous results indicated that the herpes simplex virus 1 (HSV-1) U{sub L}31 gene is necessary and sufficient for localization of the U{sub L}34 protein exclusively to the nuclear membrane of infected Hep2 cells. In the current studies, a bacterial artificial chromosome containing the entire HSV-1 strain F genome was used to construct a recombinant viral genome in which a gene encoding kanamycin resistance was inserted in place of 262 codons of the 306 codon U{sub L}31 open reading frame. The deletion virus produced virus titers approximately 10- to 50-fold lower in rabbit skin cells, more than 2000-fold lower in Vero cells, and more than 1500-fold lower in CV1 cells, compared to a virus bearing a restored U{sub L}31 gene. The replication of the U{sub L}31 deletion virus was restored on U{sub L}31-complementing cell lines derived either from rabbit skin cells or CV1 cells. Confocal microscopy indicated that the majority of U{sub L}34 protein localized aberrantly in the cytoplasm and nucleoplasm of Vero cells and CV1 cells, whereas U{sub L}34 protein localized at the nuclear membrane in rabbit skin cells, and U{sub L}31 complementing CV1 cells infected with the U{sub L}31 deletion virus. We conclude that rabbit skin cells encode a function that allows proper localization of U{sub L}34 protein to the nuclear membrane. We speculate that this function partially complements that of U{sub L}31 and may explain why U{sub L}31 is less critical for replication in rabbit skin cells as opposed to Vero and CV1 cells.

  2. Chloroplast DNA levels and the control of chloroplast division in light-grown wheat leaves.

    PubMed

    Boffey, S A; Leech, R M

    1982-06-01

    Plastids at different stages of development were isolated from light-grown wheat (Triticum aestivum, var. Maris Dove) seedling leaves, and the average chloroplast DNA (cpDNA) per plastid at each developmental stage was measured directly. In the earliest stages of development, the number of plastids per cell and the amount of cpDNA per cell increased with cell age, but cpDNA per plastid remained constant at between 800 and 1,000 genome copies per plastid. After this phase, plastids per cell continued to increase, but cpDNA per plastid decreased. Subsequently, both plastids per cell and cpDNA per plastid remained constant as cell age increased, the final DNA content being approximately 300 genome copies per plastid. These results are related to previous reports of cpDNA changes during the development of dicotyledonous plants, and to theories about the regulation of chloroplast numbers per cell. PMID:16662409

  3. Enhancement of Immune Activation Activities of Spirulina maxima Grown in Deep-Sea Water

    PubMed Central

    Choi, Woon Yong; Kang, Do Hyung; Lee, Hyeon Yong

    2013-01-01

    In this study, the immuno-modulatory and anticancer activities of marine algae, Spirulina maxima grown in deep-sea water (DSW), were investigated. It was found that the extract of S. maxima, cultured in DSW, effectively suppressed the expression of Bcl2 in A549 cells as well as inhibiting various human cancer cells with concentration dependency, which possibly implies that the extracts may play more important roles in controlling cancer cell growth. The secretion of cytokines IL-6 and TNF-? from human B cells was also greatly increased, compared to those of the extract grown in conventional sea-water. The growth of Human Natural Killer (NK) cells in the presence of the extracts from DSW was significantly higher (12.2 × 104 viable cells/mL) when compared to the control (1.1 × 104 viable cells/mL). Based on HPLC analysis, the increase in the biological activities of the extracts from DSW was caused by considerably high amounts of ?-carotene and ascorbic acid because the DSW contained high concentrations and good ratios of several key minerals for biosynthesizing ?-carotene and ascorbic acid, as well as maintaining high cell growth. PMID:23743830

  4. Defect study in molecular beam epitaxy-grown HgCdTe films with activated and unactivated arsenic

    SciTech Connect

    Izhnin, I. I., E-mail: i.izhnin@carat.electron.ua [R and D Institute for Materials SRC “Carat,” Lviv 79031 (Ukraine); National Research Tomsk State University, Tomsk 634050 (Russian Federation); Dvoretsky, S. A.; Mikhailov, N. N.; Varavin, V. S. [A.V. Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090 (Russian Federation); Mynbaev, K. D. [Ioffe Physical-Technical Institute of the Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); ITMO University, St. Petersburg 197101 (Russian Federation); Fitsych, O. I. [P. Sahaydachnyi Army Academy, Lviv 79012 (Ukraine); Pociask-Bialy, M.; Sheregii, E. [Center of Microelectronics and Nanotechnology, Rzeszów University, Rzeszów 35-310 (Poland); Voitsekhovskii, A. V. [National Research Tomsk State University, Tomsk 634050 (Russian Federation)

    2014-04-28

    A defect study was performed on molecular beam epitaxy-grown HgCdTe films in situ doped with arsenic. Doping was performed from either effusion cell or cracker cell, and studied were both as-grown samples and samples subjected to arsenic activation annealing. Electrical properties of the films were investigated with the use of ion milling as a means of “stirring” defects in the material. As a result of the study, it was confirmed that the most efficient incorporation of electrically active arsenic occurs at the cracking zone temperature of 700?°C. Interaction between arsenic and tellurium during the growth was observed and is discussed in the paper.

  5. Growth and heavy metals accumulation potential of microalgae grown in sewage wastewater and petrochemical effluents.

    PubMed

    Ajayan, K V; Selvaraju, M; Thirugnanamoorthy, K

    2011-08-15

    Microalgae exhibit a number of heavy metal uptake process by different metabolism. In this study, the ability of microalgae for removal of heavy metal from wastewater was studied. Growth and biochemical contents of microalgae were determined by spectrophotometer. Heavy metal analysis of wastewater effluents were performed by atomic absorption spectrophotometer before and after treatment at laboratory scale. The growth of Scenedesmus bijuga and Oscillatoria quadripunctulata in sewage wastewater was higher than those grown in synthetic medium. Whereas, the growth of S. bijuga and O. quadripunctulata in sterilized petrochemical effluents was slightly lower than that grown in the standard synthetic medium. The chlorophyll, carotenoid and protein content of S. bijuga and O. quadripunctulata grown in sterilized sewage wastewater were higher than those grown in the standard medium. Similarly S. bijuga and O. quadripunctulata grown in sterilized petrochemical effluents showed lower contents of pigments and protein than those grown in sewage and synthetic medium. Heavy metals copper, cobalt, lead and zinc were removed by 37-50, 20.3-33.3, 34.6-100 and 32.1-100%, respectively from sewage wastewater and petrochemical effluent using Ocillatoria culture. The metal absorption by S. bijuga were (Cu, Co, Pb, Zn) 60-50, 29.6-66, 15.4-25 and 42.9-50%, respectively from sewage and petrochemical effluents. Both species showed high level of heavy metal removal efficiency and metal sorption efficiency of both microalgae depended on the type of biosorbent, the physiological status of the cells, availability of heavy metal, concentration of heavy metal and chemical composition of wastewater. PMID:22545355

  6. The virion N protein of infectious bronchitis virus is more phosphorylated than the N protein from infected cell lysates

    SciTech Connect

    Jayaram, Jyothi [Department of Veterinary Pathobiology, Texas A and M University, College Station, TX 77843-4467 (United States); Department of Biology, Texas A and M University, College Station, TX 77843-3258 (United States); Youn, Soonjeon [Department of Veterinary Pathobiology, Texas A and M University, College Station, TX 77843-4467 (United States); Collisson, Ellen W. [Department of Veterinary Pathobiology, Texas A and M University, College Station, TX 77843-4467 (United States)]. E-mail: ecollisson@cvm.tamu.edu

    2005-08-15

    Because phosphorylation of the infectious bronchitis virus (IBV) nucleocapsid protein (N) may regulate its multiple roles in viral replication, the dynamics of N phosphorylation were examined. {sup 32}P-orthophosphate labeling and Western blot analyses confirmed that N was the only viral protein that was phosphorylated. Pulse labeling with {sup 32}P-orthophosphate indicated that the IBV N protein was phosphorylated in the virion, as well as at all times during infection in either chicken embryo kidney cells or Vero cells. Pulse-chase analyses followed by immunoprecipitation of IBV N proteins using rabbit anti-IBV N polyclonal antibody demonstrated that the phosphate on the N protein was stable for at least 1 h. Simultaneous labeling with {sup 32}P-orthophosphate and {sup 3}H-leucine identified a 3.5-fold increase in the {sup 32}P:{sup 3}H counts per minute (cpm) ratio of N in the virion as compared to the {sup 32}P:{sup 3}H cpm ratio of N in the cell lysates from chicken embryo kidney cells, whereas in Vero cells the {sup 32}P:{sup 3}H cpm ratio of N from the virion was 10.5-fold greater than the {sup 32}P:{sup 3}H cpm ratio of N from the cell lysates. These studies are consistent with the phosphorylation of the IBV N playing a role in assembly or maturation of the viral particle.

  7. Quantitative Schlieren analysis applied to holograms of crystals grown on Spacelab 3

    NASA Technical Reports Server (NTRS)

    Brooks, Howard L.

    1986-01-01

    In order to extract additional information about crystals grown in the microgravity environment of Spacelab, a quantitative schlieren analysis technique was developed for use in a Holography Ground System of the Fluid Experiment System. Utilizing the Unidex position controller, it was possible to measure deviation angles produced by refractive index gradients of 0.5 milliradians. Additionally, refractive index gradient maps for any recorded time during the crystal growth were drawn and used to create solute concentration maps for the environment around the crystal. The technique was applied to flight holograms of Cell 204 of the Fluid Experiment System that were recorded during the Spacelab 3 mission on STS 51B. A triglycine sulfate crystal was grown under isothermal conditions in the cell and the data gathered with the quantitative schlieren analysis technique is consistent with a diffusion limited growth process.

  8. Magnetization dynamics of cobalt grown on graphene

    SciTech Connect

    Berger, A. J.; White, S. P.; Adur, R.; Pu, Y.; Hammel, P. C., E-mail: hammel@physics.osu.edu [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Amamou, W. [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States); Kawakami, R. K. [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States)

    2014-05-07

    Ferromagnetic resonance (FMR) spin pumping is a rapidly growing field which has demonstrated promising results in a variety of material systems. This technique utilizes the resonant precession of magnetization in a ferromagnet to inject spin into an adjacent non-magnetic material. Spin pumping into graphene is attractive on account of its exceptional spin transport properties. This article reports on FMR characterization of cobalt grown on chemical vapor deposition graphene and examines the validity of linewidth broadening as an indicator of spin pumping. In comparison to cobalt samples without graphene, direct contact cobalt-on-graphene exhibits increased FMR linewidth—an often used signature of spin pumping. Similar results are obtained in Co/MgO/graphene structures, where a 1?nm MgO layer acts as a tunnel barrier. However, magnetometry, magnetic force microscopy, and Kerr microscopy measurements demonstrate increased magnetic disorder in cobalt grown on graphene, perhaps due to changes in the growth process and an increase in defects. This magnetic disorder may account for the observed linewidth enhancement due to effects such as two-magnon scattering or mosaicity. As such, it is not possible to conclude successful spin injection into graphene from FMR linewidth measurements alone.

  9. Magnetic and structural properties of MBE-grown oxidic multilayers

    SciTech Connect

    Bloemen, P.J.H.; Heijden, P.A.A. van der; Kohlhepp, J.T.; Jonge, W.J.M. de [Eindhoven Univ. of Technology (Netherlands). Dept. of Physics; Wolf, R.M.; Stegge, J. aan de; Reinders, A.; Jungblut, R.M.; Zaag, P.J. van der [Philips Research Labs., Eindhoven (Netherlands)

    1996-11-01

    Multilayers composed of oxides including Fe{sub 3}O{sub 4}, Co{sub x}Fe{sub 3{minus}x}O{sub 4}, CoO, NiO and MgO have been grown epitaxially by MBE on MgO(100) single crystal substrates. These structures can be grown with a high crystallinity in the form of flat layers having sharp interfaces. RHEED studies which commonly yielded sharp streaks accompanied by Kikuchi lines show that, for instance, growth of CoO on Fe{sub 3}O{sub 4} changes the RHEED pattern form from that consistent with a spinel structure to that of a rocksalt structure within about one and a half unit cell of CoO. STM studies on a 400 {angstrom} Fe{sub 3}O{sub 4} layer displaying atomic resolution enabled us to identify the origin of the reconstruction that one commonly observes in the RHEED and LEED patterns for magnetite. Regarding important fundamental magnetic parameters, relevant thickness dependencies were mapped out using localized magneto-optical Kerr effect experiments performed on several samples that routinely included one or multiple wedge shaped layers. These studies revealed the existence of a region in the Fe{sub 3}O{sub 4} layer near the interfaces which exhibits no net magnetic moment, strain driven perpendicular orientated magnetization for the CoO/Fe{sub 3}O{sub 4}(100) and CoO/Co{sub x}Fe{sub 3{minus}x}O{sub 4}(100) bilayer systems, and information on the thickness dependence of the magnetic interlayer coupling across an MgO spacer layer.

  10. Revised stereochemistry of ficifolidione and its biological activities against insects and cells.

    PubMed

    Nishiwaki, Hisashi; Fujiwara, Satomi; Wukirsari, Tuti; Iwamoto, Hiroyuki; Mori, Shigeki; Nishi, Kosuke; Sugahara, Takuya; Yamauchi, Satoshi; Shuto, Yoshihiro

    2015-01-23

    Ficifolidione (1), a moderately active insecticidal compound from two species of Myrtaceae, and its derivatives were synthesized to evaluate their insecticidal activity. X-ray crystallographic analyses and specific rotation values of ficifolidione and its C-4 (2) demonstrated that the structure of ficifolidione differs from the reported absolute structure; that is, the C-4 configuration of ficifolidione should have an S configuration. The reported insecticidal activity of ficifolidione (1) and its C-4 epimer (2) against adult houseflies (Musca domestica), mosquito larvae (Culex pipiens), and cutworms (Spodoptera litura) was not observed. The cytotoxicities of ficifolidione and its derivatives (1-4) against four cell lines, Sf9, Colon26, HL60, and Vero, were also measured because ficifolidione has a phloroglucinol-derived moiety, a motif that is often present in the structure of cytotoxic chemicals. Compound 1 exhibited IC50 values of ca. 32, 9, 3, and 12 ?M for Sf9, Colon26, HL60, and Vero cells, respectively, indicating that ficifolidione possesses selective cytotoxicity against the four cell lines. In HL60 cells treated with 1, DNA fragmentation and the activation of procaspase 3 were observed, suggesting that the cytotoxicity is induced by apoptosis. PMID:25495518

  11. Cratoxylum formosum (Jack) Dyer ssp. pruniflorum (Kurz) Gogel. (Hóng yá mù) extract induces apoptosis in human hepatocellular carcinoma HepG2 cells through caspase-dependent pathways

    PubMed Central

    2014-01-01

    Background Cratoxylum formosum (Jack) Dyer ssp. pruniflorum (Kurz) Gogel. (Hóng yá mù) (CF) has been used for treatment of fever, cough, and peptic ulcer. Previously, a 50% ethanol-water extract from twigs of CF was shown highly selective in cytotoxicity against cancer cells. This study aims to investigate the molecular mechanisms underlying the apoptosis-inducing effect of CF. Methods The cytotoxicity of CF was evaluated in the human hepatocellular carcinoma (HCC) HepG2 cell line in comparison with a non-cancerous African green monkey kidney epithelial cell line (Vero) by a neutral red assay. The apoptosis induction mechanisms were investigated through nuclear morphological changes, DNA fragmentation, mitochondrial membrane potential alterations, and caspase enzyme activities. Results CF selectively induced HepG2 cell death compared with non-cancerous Vero cells. A 1.5-fold higher apoptotic effect compared with melphalan was induced by 120 ?g/mL of the 50% ethanol-water extract of CF. The apoptotic cell death in HepG2 cells occurred via extrinsic and intrinsic caspase-dependent pathways in dose- and time-dependent manners by significantly increasing the activities of caspase 3/7, 8, and 9, decreasing the mitochondrial membrane potential, and causing apoptotic body formation and DNA fragmentation. Conclusions CF extract induced a caspase-dependent apoptosis in HepG2 cells. PMID:24708784

  12. Encystment of Azotobacter nigricans grown diazotrophically on kerosene as sole carbon source

    Microsoft Academic Search

    Gabriela García-Esquivel; Graciano Calva-Calva; Ronald Ferrera-Cerrato; Luis Carlos Fernández-Linares; Refugio Rodríguez Vázquez; Fernando José Esparza-García

    2009-01-01

    Encystment of Azotobacter nigricans was induced by its diazotrophic cultivation on kerosene. Its growth and nitrogenase activity were affected by kerosene in\\u000a comparison to cultures grown on sucrose. Electron microscopy of vegetative cells showed that when nitrogenase activity was\\u000a higher and the poly-?-hydroxybutyrate granules were not present to a significant extent, peripheral bodies were abundant.\\u000a After 8 days of culture on

  13. Electron-transport chain and coupled oxidative phosphorylation in methanol-grown Paracoccus denitrificans

    Microsoft Academic Search

    H. W. Van Verseveld; A. H. Stouthamer

    1978-01-01

    Methanol dehydrogenase of Paracoccus denitrificans was shown to be very similar to the enzyme of Pseudomonas sp, M. 27. The Km value for methanol with excess activator (ammonium ions) is 35 µM. The pH optimum for enzyme activity with 2,6-dichlorophe-nolindophenol as electronacceptor was at 9.0 A CO-binding type of cytochrome c was present only in cells grown with methanol as

  14. Method for Theoretical Prediction of Indium Composition in Coherently Grown InGaN Thin Films

    Microsoft Academic Search

    Tomoe Yayama; Yoshihiro Kangawa; Koichi Kakimoto; Akinori Koukitu

    2009-01-01

    InxGa1-xN has attracted considerable interest as a material for multi junction solar cells. In this study, we performed thermodynamic analyses to calculate the relationship between the input In molar ratio and solid composition of a coherently grown InxGa1-xN thin film that is subjected to planar compressive or tensile stress. The theoretical approach incorporates energy loss of a thin-film system due

  15. Proton translocation coupled to dimethyl sulfoxide reduction in anaerobically grown Escherichia coli HB101

    Microsoft Academic Search

    P. T. Bilous; J. H. Weiner

    1985-01-01

    Proton translocation coupled to dimethyl sulfoxide (DMSO) reduction was examined in Escherichia coli HB101 grown anaerobically on glycerol and DMSO. Rapid acidification of the medium was observed when an anaerobic suspension of cells, preincubated with glycerol, was pulsed with DMSO, methionine sulfoxide, nitrate, or trimethylamine N-oxide. The DMSO-induced acidification was sensitive to the uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone (60 microM) and

  16. Nine new diterpenes from the leaves of plantation-grown Cunninghamia lanceolata.

    PubMed

    Zhao, Shuangshuang; Ling, Junhong; Li, Zhanlin; Wang, Silong; Hu, Jiangchun; Wang, Nan

    2015-04-01

    Nine new diterpenes named lanceolatanol hydroperoxide (1), epilanceolatanol hydroperoxide (2), lanceolatanoic acid hydroperoxide (3), epilanceolatanoic acid hydroperoxide (4), lanceolatanol (5), lanceolatanoic acid (6), 11-acetoxylanceolatanoic acid (7), 11-acetoxylanceolatanoic acid methyl ester (8) and epoxyhinokiol (13) were characterized from the leaves of plantation-grown Cunninghamia lanceolata along with twelve known compounds. The compounds were evaluated for their growth inhibitory activities against the human prostate cell line (PC-3). PMID:25736997

  17. Chloroplasts of salt-grown Arabidopsis seedlings are impaired in structure, genome copy number and transcript levels.

    PubMed

    Peharec Štefani?, Petra; Koffler, Tal; Adler, Guy; Bar-Zvi, Dudy

    2013-01-01

    The chloroplast is the most prominent and metabolically active plastid in photosynthetic plants. Chloroplasts differentiate from proplastids in the plant meristem. Plant plastids contain multiple copies of a small circular genome. The numbers of chloroplasts per mesophyll cell and of plastid genome copies are affected by developmental stage and environmental signals. We compared chloroplast structure, gene expression and genome copy number in Arabidopsis seedlings germinated and grown under optimal conditions to those in seedlings germinated and grown in the presence of NaCl. Chloroplasts of the NaCl-grown seedlings were impaired, with less developed thylakoid and granum membranes than control seedlings. In addition, chloroplasts of salt-grown Arabidopsis seedlings accumulated more starch grains than those in the respective control plants. Steady-state transcript levels of chloroplast-encoded genes and of nuclear genes encoding chloroplast proteins were reduced in salt-grown seedlings. This reduction did not result from a global decrease in gene expression, since the expression of other nuclear genes was induced or not affected. Average cellular chloroplast genome copy number was reduced in salt-grown seedlings, suggesting that the reduction in steady-state transcript levels of chloroplast-encoded genes might result from a decrease in template DNA. PMID:24340039

  18. Chloroplasts of Salt-Grown Arabidopsis Seedlings Are Impaired in Structure, Genome Copy Number and Transcript Levels

    PubMed Central

    Adler, Guy; Bar-Zvi, Dudy

    2013-01-01

    The chloroplast is the most prominent and metabolically active plastid in photosynthetic plants. Chloroplasts differentiate from proplastids in the plant meristem. Plant plastids contain multiple copies of a small circular genome. The numbers of chloroplasts per mesophyll cell and of plastid genome copies are affected by developmental stage and environmental signals. We compared chloroplast structure, gene expression and genome copy number in Arabidopsis seedlings germinated and grown under optimal conditions to those in seedlings germinated and grown in the presence of NaCl. Chloroplasts of the NaCl-grown seedlings were impaired, with less developed thylakoid and granum membranes than control seedlings. In addition, chloroplasts of salt-grown Arabidopsis seedlings accumulated more starch grains than those in the respective control plants. Steady-state transcript levels of chloroplast-encoded genes and of nuclear genes encoding chloroplast proteins were reduced in salt-grown seedlings. This reduction did not result from a global decrease in gene expression, since the expression of other nuclear genes was induced or not affected. Average cellular chloroplast genome copy number was reduced in salt-grown seedlings, suggesting that the reduction in steady-state transcript levels of chloroplast-encoded genes might result from a decrease in template DNA. PMID:24340039

  19. Multicellularity and Antibiotic Resistance in Klebsiella pneumoniae Grown Under Bloodstream-Mimicking Fluid Dynamic Conditions

    PubMed Central

    Thornton, Margaret M.; Chung-Esaki, Hangyul M.; Irvin, Charlene B.; Bortz, David M.; Solomon, Michael J.; Younger, John G.

    2012-01-01

    Background.?While the importance of fluid dynamical conditions is well recognized in the growth of biofilms, their role during bacteremia is unknown. We examined the impact of physiological fluid shear forces on the development of multicellular aggregates of Klebsiella pneumoniae. Methods.?Wild-type and O-antigen or capsular mutants of K. pneumoniae were grown as broth culture in a Taylor-Couette flow cell configured to provide continuous shear forces comparable to those encountered in the human arterial circulation (ie, on the order of 1.0 Pa). The size distribution and antibiotic resistance of aggregates formed in this apparatus were determined, as was their ability to persist in the bloodstream of mice following intravenous injection. Results.?Unlike growth in shaking flasks, bacteria grown in the test apparatus readily formed aggregates, a phenotype largely absent in capsular mutants and to a lesser degree in O-antigen mutants. Aggregates were found to persist in the bloodstream of mice. Importantly, organisms grown under physiological shear were found to have an antibiotic resistance phenotype intermediate between that of fully planktonic and biofilm states. Conclusions.?When grown under intravascular-magnitude fluid dynamic conditions, K. pneumoniae spontaneously develops into multicellular aggregates that are capable of persisting in the circulation and exhibit increased antibiotic resistance. PMID:22711903

  20. Phase-shifting interferometric holography of living cells

    NASA Astrophysics Data System (ADS)

    Giel, Dominik M.; Fratz, Markus; Brandenburg, Albrecht

    2006-02-01

    We present a phase-shifting holographic set-up for the microscopic imaging of adherent cells. The superposition of an object wave field and a reference wave is recorded on a digital sensor with three reference wave phases. The reference phases are then recovered by statistical analysis of the recorded intensities. Subsequently, the object wave phase is calculated by the generalized phase shifting algorithm. After phase unwrapping and background subtraction, the phase shift introduced by the adherent cell culture is reconstructed. As the interferograms are recorded in the image plane of the microsope objective, the full lateral resolution is achieved in contrast to off-axis holography where the reconstruction requires numerical propagation for the separation of 0 th and 1 st order. Our approach uses three arbitrary unknown reference phases and poses thus minimum requirements on the mechanical and thermal stability of the set-up. We give preliminary results of images from a Vero cell line and pollen grains.

  1. Cells

    NSDL National Science Digital Library

    Integrated Teaching and Learning Program,

    In this unit, students look at the components of cells and their functions and discover the controversy behind stem cell research. The first lesson focuses on the difference between prokaryotic and eukaryotic cells. In the second lesson, students learn about the basics of cellular respiration. They also learn about the application of cellular respiration to engineering and bioremediation. The third lesson continues students' education on cells in the human body and how (and why) engineers are involved in the research of stem cell behavior.

  2. Perfect crystals grown from imperfect interfaces

    PubMed Central

    Falub, Claudiu V.; Medu?a, Mojmír; Chrastina, Daniel; Isa, Fabio; Marzegalli, Anna; Kreiliger, Thomas; Taboada, Alfonso G.; Isella, Giovanni; Miglio, Leo; Dommann, Alex; von Känel, Hans

    2013-01-01

    The fabrication of advanced devices increasingly requires materials with different properties to be combined in the form of monolithic heterostructures. In practice this means growing epitaxial semiconductor layers on substrates often greatly differing in lattice parameters and thermal expansion coefficients. With increasing layer thickness the relaxation of misfit and thermal strains may cause dislocations, substrate bowing and even layer cracking. Minimizing these drawbacks is therefore essential for heterostructures based on thick layers to be of any use for device fabrication. Here we prove by scanning X-ray nanodiffraction that mismatched Ge crystals epitaxially grown on deeply patterned Si substrates evolve into perfect structures away from the heavily dislocated interface. We show that relaxing thermal and misfit strains result just in lattice bending and tiny crystal tilts. We may thus expect a new concept in which continuous layers are replaced by quasi-continuous crystal arrays to lead to dramatically improved physical properties. PMID:23880632

  3. Compound semiconductor nanotube materials grown and fabricated

    NASA Astrophysics Data System (ADS)

    Ai, Likun; Xu, Anhuai; Teng, Teng; Niu, Jiebin; Sun, Hao; Qi, Ming

    2011-12-01

    A new GaAs/InGaAs/InGaP compound semiconductor nanotube material structure was designed and fabricated in this work. A thin, InGaAs-strained material layer was designed in the nanotube structure, which can directionally roll up a strained heterostructure through a normal wet etching process. The compound semiconductor nanotube structure was grown by gas-source molecular beam epitaxy. A good crystalline quality of InGaP, InGaAs, and GaAs materials was obtained through optimizing the growth condition. The fabricated GaAs/InGaAs/InGaP semiconductor nanotubes, with a diameter of 300 to 350 nm and a length of 1.8 to 2.0 ?m, were achieved through normal device fabrication.

  4. Cotton Fibers Can Undergo Cell Division

    Microsoft Academic Search

    Jack Van't Hof; Sukumar Saha

    1997-01-01

    Ovular culture was used to determine the cell cycle aspects of cotton fiber cells. Each ovule (Gossypium hirsutum,cultivar, MD51 ne) grown under the conditions used has ;10 000 fiber cells at 4 d postanthesis. About 25% of these cells divide when ovules are cultured at 348C. Mitosis occurs after fiber cells differentiate, producing multicelled fibers. The basal and tip cells

  5. Nanoelectronic biosensors based on CVD grown graphene

    NASA Astrophysics Data System (ADS)

    Huang, Yinxi; Dong, Xiaochen; Shi, Yumeng; Li, Chang Ming; Li, Lain-Jong; Chen, Peng

    2010-08-01

    Graphene, a single-atom-thick and two-dimensional carbon material, has attracted great attention recently. Because of its unique electrical, physical, and optical properties, graphene has great potential to be a novel alternative to carbon nanotubes in biosensing. We demonstrate the use of large-sized CVD grown graphene films configured as field-effect transistors for real-time biomolecular sensing. Glucose or glutamate molecules were detected by the conductance change of the graphene transistor as the molecules are oxidized by the specific redox enzyme (glucose oxidase or glutamic dehydrogenase) functionalized onto the graphene film. This study indicates that graphene is a promising candidate for the development of real-time nanoelectronic biosensors.Graphene, a single-atom-thick and two-dimensional carbon material, has attracted great attention recently. Because of its unique electrical, physical, and optical properties, graphene has great potential to be a novel alternative to carbon nanotubes in biosensing. We demonstrate the use of large-sized CVD grown graphene films configured as field-effect transistors for real-time biomolecular sensing. Glucose or glutamate molecules were detected by the conductance change of the graphene transistor as the molecules are oxidized by the specific redox enzyme (glucose oxidase or glutamic dehydrogenase) functionalized onto the graphene film. This study indicates that graphene is a promising candidate for the development of real-time nanoelectronic biosensors. Electronic supplementary information (ESI) available: AFM images of graphene film before and after functionalization, transfer curves of graphene after every step, SEM image of CNT-net, and detection results using CNT-net devices. See DOI: 10.1039/c0nr00142b

  6. MATERIALS AND METHODS Cell culture

    E-print Network

    cell line hCMEC/D3 which retains the main characteristics of primary brain endothelial cells, has beenMATERIALS AND METHODS Reagents Cell culture The immortalized human brain microvessel endothelial previously described (S1). hCMEC/D3 were grown at a density of 25 000 cells per cm2 in flasks coated with 5

  7. Ultraviolet photoconductive detectors based on Ga-doped ZnO films grown by molecular-beam epitaxy

    E-print Network

    Yang, Zheng

    on in-depth studies of photoelectric properties and device performances are still few. In this paper, we study optical and photoelectric properties of Ga-doped ZnO films and the corresponding photoconductive was maintained at 550 °C during growth. Ga-doped ZnO film was grown using effusion cell temperatures of 350 °C

  8. [Development of a novel influenza vaccine derived from a continuous cell line].

    PubMed

    Kistner, O; Barrett, N; Mundt, W; Reiter, M; Schober-Bendixen, S; Eder, G; Dorner, F

    2001-01-01

    Influenza viruses for production are presently produced in embryonated hen"s eggs. This conventional standard methodology is extremely cumbersome; it requires millions of eggs and an extensive purification to reduce the amount of contaminating egg proteins and to minimise the risk of allergies against egg albumin. The shortage of eggs in a pandemic situation, the selection of egg-adapted variants and the presence of adventitious viruses has emphasised the necessity for production of Influenza vaccines on a well characterised stable cell line. Our established serum and protein free Vero cell technology has been successfully adapted to large scale production of a huge variety of Influenza virus strains. The production in 1200 liter fermenter cultures under serum free conditions gave antigen yields comparable to the conventional embryonated egg technology. The development of a rapid and efficient purification scheme resulted in a safe high purity vaccine which was at least as immunogenic as conventional egg-derived vaccines in a mouse model. Clinical trials in the UK, Poland and Austria demonstrated that the Vero cell derived influenza vaccine is well tolerated, safe and highly immunogenic in humans. PMID:11248852

  9. Plasma-Mediated Inactivation of Pseudomonas aeruginosa Biofilms Grown on Borosilicate Surfaces under Continuous Culture System

    PubMed Central

    Vandervoort, Kurt G.; Brelles-Mariño, Graciela

    2014-01-01

    Biofilms are microbial communities attached to a surface and embedded in a matrix composed of exopolysaccharides and excreted nucleic acids. Bacterial biofilms are responsible for undesirable effects such as disease, prostheses colonization, biofouling, equipment damage, and pipe plugging. Biofilms are also more resilient than free-living cells to regular sterilization methods and therefore it is indispensable to develop better ways to control and remove them. The use of gas discharge plasmas is a good alternative since plasmas contain a mixture of reactive agents well-known for their decontamination potential against free microorganisms. We have previously reported that Pseudomonas aeruginosa biofilms were inactivated after a 1-min plasma exposure. We determined that the adhesiveness and the thickness of Pseudomonas biofilms grown on borosilicate were reduced. We also reported sequential morphological changes and loss of viability upon plasma treatment. However, the studies were carried out in batch cultures. The use of a continuous culture results in a more homogenous environment ensuring reproducible biofilm growth. The aim of this work was to study plasma-mediated inactivation of P. aeruginosa biofilms grown on borosilicate in a continuous culture system. In this paper we show that biofilms grown on glass under continuous culture can be inactivated by using gas discharge plasma. Both biofilm architecture and cell culturabilty are impacted by the plasma treatment. The inactivation kinetics is similar to previously described ones and cells go through sequential changes ranging from minimal modification without loss of viability at short plasma exposure times, to major structure and viability loss at longer exposure times. We report that changes in biofilm structure leading to the loss of culturability and viability are related to a decrease of the biofilm matrix adhesiveness. To our knowledge, there has been no attempt to evaluate the inactivation/sterilization of biofilms grown in a continuous system. PMID:25302815

  10. Chloroplast Division and DNA Synthesis in Light-grown Wheat Leaves 1

    PubMed Central

    Boffey, Stephen A.; Ellis, J. Raymond; Selldén, Gun; Leech, Rachel M.

    1979-01-01

    Light-grown 7-day-old wheat seedlings (Triticum aestivum, var. Maris Dove) showed an increase of 200% in plastids per cell between 1.7 and 4.5 centimeters from the leaf base. This increase was the result of divisions of young chloroplasts at various stages of development, and was well separated in distance, and therefore in time from the region of cell division in the basal meristem. [3H]Thymidine was incorporated into plastid DNA throughout the zone of plastid division, but not above it. Images PMID:16660998

  11. In vitro anticancer activity of fucoidan from Turbinaria conoides against A549 cell lines.

    PubMed

    Marudhupandi, Thangapandi; Ajith Kumar, Thipramalai Thankappan; Lakshmanasenthil, Shanmugaasokan; Suja, Gunasekaran; Vinothkumar, Thirumalairaj

    2015-01-01

    The present study was conducted to evaluate the anticancer activity of fucoidan isolated from brown seaweed Turbinaria conoides. Extracted fucoidan contained 53 ± 0.69% of fucose and 38 ± 0.42% of sulphate, respectively. Functional groups and structural characteristics of the fucoidan were analyzed by FT-IR and NMR. In vitro anticancer effect was studied on A549 cell line. Fucoidan inhibited the growth of cancer cells in a dose-dependent manner and potent anticancer activities were 24.9-73.5% in the concentrations of 31.25-500 ?g/ml. The CTC50 value against the cancer cell was found to be 45 ?g/ml and the CTC50 value of normal Vero cell line is 325 ?g/ml. This study suggests that the fucoidan from T. conoides could be significantly improved if the active component is further purified and tested for further investigation in various cancer cell lines. PMID:25451746

  12. Phyllosphere Microbiota Composition and Microbial Community Transplantation on Lettuce Plants Grown Indoors

    PubMed Central

    Williams, Thomas R.

    2014-01-01

    ABSTRACT The aerial surfaces of plants, or phyllosphere, are microbial habitats important to plant and human health. In order to accurately investigate microbial interactions in the phyllosphere under laboratory conditions, the composition of the phyllosphere microbiota should be representative of the diversity of microorganisms residing on plants in nature. We found that Romaine lettuce grown in the laboratory contained 10- to 100-fold lower numbers of bacteria than age-matched, field-grown lettuce. The bacterial diversity on laboratory-grown plants was also significantly lower and contained relatively higher proportions of Betaproteobacteria as opposed to the Gammaproteobacteria-enriched communities on field lettuce. Incubation of field-grown Romaine lettuce plants in environmental growth chambers for 2 weeks resulted in bacterial cell densities and taxa similar to those on plants in the field but with less diverse bacterial populations overall. In comparison, the inoculation of laboratory-grown Romaine lettuce plants with either freshly collected or cryopreserved microorganisms recovered from field lettuce resulted in the development of a field-like microbiota on the lettuce within 2 days of application. The survival of an inoculated strain of Escherichia coli O157:H7 was unchanged by microbial community transfer; however, the inoculation of E. coli O157:H7 onto those plants resulted in significant shifts in the abundance of certain taxa. This finding was strictly dependent on the presence of a field-associated as opposed to a laboratory-associated microbiota on the plants. Phyllosphere microbiota transplantation in the laboratory will be useful for elucidating microbial interactions on plants that are important to agriculture and microbial food safety. PMID:25118240

  13. 78 FR 45898 - Vidalia Onions Grown in Georgia; Continuance Referendum

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-30

    ...AMS-FV-13-0037; FV13-955-2 CR] Vidalia Onions Grown in Georgia; Continuance Referendum...conducted among eligible producers of Vidalia onions grown in Georgia to determine whether...that regulates the handling of Vidalia onions produced in the production area....

  14. 29 CFR 780.813 - “County where cotton is grown

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false âCounty where cotton is grown.â 780.813 Section 780...STANDARDS ACT Employment in Ginning of Cotton and Processing of Sugar Beets, Sugar-Beet...Section 13(b)(15) County Where Cotton Is Grown in Commercial Quantities...

  15. Vapor grown silicon dioxide improves transistor base-collector junctions

    NASA Technical Reports Server (NTRS)

    Carley, D. R.; Duclos, R. A.

    1966-01-01

    Vapor grown silicon dioxide layer protects base-collector junction in silicon planar transistors during the emitter diffusion process. This oxide fills in any imperfections that exist in the thermally grown oxide layer and is of greater thickness than that layer. This process is used to deposit protective silicon dioxide coatings on optical surfaces.

  16. Thermoelectic properties of CVD grown large area graphene

    Microsoft Academic Search

    Andriy Sherehiy

    2010-01-01

    This thesis is based on experimental work on thermoelectric properties of CVD grown large area graphene. The thermoelectric power (TEP) of CVD (Chemical Vapor Deposition) grown large area graphene transferred onto a Si\\/SiO 2_substrate was measured by simply attaching two miniature thermocouples and a resistive heater. Availability of such large area graphene facilitates straight forward TEP measurement without the use

  17. 78 FR 77367 - Almonds Grown in California; Continuance Referendum

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-23

    ...AMS-FV-13-0082; FV14-981-1 CR] Almonds Grown in California; Continuance Referendum...be conducted among eligible growers of almonds in California to determine whether they...marketing order that regulates the handling of almonds grown in California. DATES: The...

  18. Theoretical and experimental study of the formation of grown-in and as-grown microdefects in dislocation-free silicon single crystals grown by the Czochralski method

    Microsoft Academic Search

    N. A. Verezub; A. I. Prostomolotov; M. V. Mezhennyi; M. G. Mil’vidskii; V. Ya. Reznik

    2005-01-01

    A complex theoretical and experimental investigation is performed, including the following stages. (i) Simulation of the processes\\u000a of the recombination of intrinsic point defects and the formation of grown-in microdefects in dislocation-free Si single crystals\\u000a 200 mm in diameter grown in modern commercial heating units. The simulation takes into account the thermal history of the\\u000a defect growth. Modified designs of

  19. Isolation of "Candidatus Rickettsia andeanae" (Rickettsiales: Rickettsiaceae) in embryonic cells of naturally infected Amblyomma maculatum (Ixodida: Ixodidae).

    PubMed

    Ferrari, F A G; Goddard, J; Moraru, G M; Smith, W E C; Varela-Stokes, A S

    2013-09-01

    The Gulf Coast tick, Amblyomma maculatum Koch, has become increasingly important in public health for its role as a vector of the recently recognized human pathogen, Rickettsia parkeri. More recently, these ticks were also found to harbor a novel spotted fever group rickettsia, "Candidatus Rickettsia andeanae." First identified in Peru, and subsequently reported in ticks collected in the United States, Chile, and Argentina, "Ca. R. andeanae" remains largely uncharacterized, in part because of the lack of a stable isolate. Although the isolation of "Ca. R. andeanae" was recently described in DH82, Vero, and Drosophila S2 cells, its stability in these cell lines was not shown. To evaluate "Ca. R. andeanae" transmission and pathogenicity in vertebrates, as well as further describe biological characteristics of this candidate species to fulfill criteria for its establishment as a new species, availability of a stable isolate is essential. Here we describe the propagation of "Ca. R. andeanae" by using a primary culture derived from naturally infected A. maculatum embryos. Subsequent passage of the "Ca. R. andeanae" isolate to ISE6 (Ixodes scapularis embryonic) and Vero (African green monkey kidney epithelial) cell lines demonstrated limited propagation of the rickettsiae. Treatment of the infected primary cells with tetracycline resulted in cultures negative for "Ca. R. andeanae" by polymerase chain reaction and microscopy. Establishment of an isolate of "Ca. R. andeanae" will promote further investigation into the significance of this tick-associated rickettsia, including its role in spotted fever and interactions with the sympatric species, R. parkeri in A. PMID:24180118

  20. Heterostructure solar cells

    NASA Technical Reports Server (NTRS)

    Chang, K. I.; Yeh, Y. C. M.; Iles, P. A.; Morris, R. K.

    1987-01-01

    The performance of gallium arsenide solar cells grown on Ge substrates is discussed. In some cases the substrate was thinned to reduce overall cell weight with good ruggedness. The conversion efficiency of 2 by 2 cm cells under AMO reached 17.1 percent with a cell thickness of 6 mils. The work described forms the basis for future cascade cell structures, where similar interconnecting problems between the top cell and the bottom cell must be solved. Applications of the GaAs/Ge solar cell in space and the expected payoffs are discussed.

  1. Rickettsial phospholipase A2 as a pathogenic mechanism in a model of cell injury by typhus and spotted fever group rickettsiae.

    PubMed

    Walker, D H; Feng, H M; Popov, V L

    2001-12-01

    Phospholipase A2 activity by typhus group rickettsiae causes hemolysis in vitro. Rickettsial phospholipase A2 has been proposed to mediate entry into the host cell, escape from the phagosome, and cause injury to host cells by both typhus and spotted fever group rickettsiae. In a rickettsial contact-associated cytotoxicity model, the interaction of Rickettsia prowazekii or R. conorii with Vero cells caused temperature-dependent release of 51Cr from the cells. Treatment of rickettsiae, but not the cells, with a phospholipase A2 inhibitor (bromophenacyl bromide) or with antibody to king cobra venom inhibited cell injury. Rickettsial treatment with bromophenacyl bromide inhibited the release of free fatty acids from the host cell. Neither the inhibitor nor antivenom impaired rickettsial active transport of L-lysine. Thus, host cell injury was mediated by a rickettsial phospholipase A2-dependent mechanism. PMID:11792002

  2. VHL Induces Renal Cell Differentiation and Growth Arrest through Integration of Cell-Cell and Cell-Extracellular Matrix Signaling

    PubMed Central

    Davidowitz, Eliot J.; Schoenfeld, Alan R.; Burk, Robert D.

    2001-01-01

    Mutations in the von Hippel-Lindau (VHL) gene are involved in the family cancer syndrome for which it is named and the development of sporadic renal cell cancer (RCC). Reintroduction of VHL into RCC cells lacking functional VHL [VHL(?)] can suppress their growth in nude mice, but not under standard tissue culture conditions. To examine the hypothesis that the tumor suppressor function of VHL requires signaling through contact with extracellular matrix (ECM), 786-O VHL(?) RCC cells and isogenic sublines stably expressing VHL gene products [VHL(+)] were grown on ECMs. Cell-cell and cell-ECM signalings were required to elicit VHL-dependent differences in growth and differentiation. VHL(+) cells differentiated into organized epithelial sheets, whereas VHL(?) cells were branched and disorganized. VHL(+) cells grown to high density on collagen I underwent growth arrest, whereas VHL(?) cells continued to proliferate. Integrin levels were up-regulated in VHL(?) cells, and cell adhesion was down-regulated in VHL(+) cells during growth at high cell density. Hepatocyte nuclear factor 1?, a transcription factor and global activator of proximal tubule-specific genes in the nephron, was markedly up-regulated in VHL(+) cells grown at high cell density. These data indicate that VHL can induce renal cell differentiation and mediate growth arrest through integration of cell-cell and cell-ECM signals. PMID:11154273

  3. APIVT-Grown Silicon Thin Layers and PV Devices: Preprint

    SciTech Connect

    Wang, T. H.; Ciszek, T. F.; Page, M. R.; Bauer, R. E.; Wang, Q.; Landry, M. D.

    2002-05-01

    Large-grained (5-20 ..mu..m) polycrystalline silicon layers have been grown at intermediate temperatures of 750-950C directly on foreign substrates without a seeding layer by iodine vapor transport at atmospheric pressure with rates as high as 3 mm/min. A model is constructed to explain the atypical temperature dependence of growth rate. We have also used this technique to grow high-quality epitaxial layers on heavily doped CZ-Si and on upgraded MG-Si substrates. Possible solar cell structures of thin-layer polycrystalline silicon on foreign substrates with light trapping have been examined, compared, and optimized by two-dimensional device simulations. The effects of grain boundary re-combination on device performance are presented for two grain sizes of 2 and 20 mm. We found that 104 cm/s recombination velocity is adequate for 20-m m grain-sized thin silicon, whereas a very low recombination velocity of 103 cm/s must be accomplished in order to achieve reasonable performance for a 2- mm grain-sized polycrystalline silicon device.

  4. Optical characteristics of silicon nanowires grown from tin catalyst layers on silicon coated glass.

    PubMed

    Ball, Jeremy; Centeno, Anthony; Mendis, Budhika G; Reehal, H S; Alford, Neil

    2012-08-27

    The optical characteristics of silicon nanowires grown on Si layers on glass have been modeled using the FDTD (Finite Difference Time Domain) technique and compared with experimental results. The wires were grown by the VLS (vapour-liquid-solid) method using Sn catalyst layers and exhibit a conical shape. The resulting measured and modeled absorption, reflectance and transmittance spectra have been investigated as a function of the thickness of the underlying Si layer and the initial catalyst layer, the latter having a strong influence on wire density. High levels of absorption (>90% in the visible wavelength range) and good agreement between the modeling and experiment have been observed when the nanowires have a relatively high density of ~4 wires/µm2. The experimental and modeled results diverge for samples with a lower density of wire growth. The results are discussed along with some implications for solar cell fabrication. PMID:23037078

  5. Irrigation frequency alters nutrient uptake in container-grown Rhododendron plants grown with different rates of nitrogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of irrigation frequency (same amount of water per day given at different times) on nutrient uptake of container-grown evergreen Rhododendron ‘P.J.M. Compact’ (PJM) and ‘English Roseum’ (ER) and deciduous Rhododendron ‘Gibraltar’ (AZ) grown with different rates of nitrogen (N) fertilize...

  6. Auxin Transport Is Required for Hypocotyl Elongation in Light-Grown but Not Dark-Grown Arabidopsis1

    E-print Network

    Estelle, Mark

    Auxin Transport Is Required for Hypocotyl Elongation in Light-Grown but Not Dark-Grown Arabidopsis1, Bloomington, Indiana 47405 Many auxin responses are dependent on redistribution and/or polar transport of indoleacetic acid. Polar transport of auxin can be inhibited through the application of phytotropins such as 1

  7. The UL13 protein kinase and the infected cell type are determinants of posttranslational modification of ICP0.

    PubMed

    Ogle, W O; Ng, T I; Carter, K L; Roizman, B

    1997-09-01

    The herpes simplex virus infected-cell protein 0 (ICP0) acts as a promiscuous transactivator of genes introduced into eukaryotic cells by transfection or infection. The protein is highly posttranslationally modified by phosphorylation and nucleotidylylation. We have examined the electrophoretic mobility and phosphorylation of ICP0 in Vero and rabbit skin cells infected with wild-type virus or viruses from which the UL13 gene (DeltaUL13) encoding a protein kinase or the alpha22/US1.5 genes (Deltaalpha22/DeltaUS1.5) encoding putative transcriptional factors has been deleted. We report the following: (i) The accumulation of ICP0 and the electrophoretic mobility of ICP0 were dependent on the nature of the infected cell type and the presence of UL13. ICP0 encoded by wild-type virus accumulated to maximum levels earlier in infected Vero cells and its electrophoretic mobility was slower than that made in rabbit skin cells. In both Vero and rabbit skin cells infected with the DeltaUL13 virus, the prevailing ICP0 form migrated faster than that accumulating in the corresponding cells infected with wild-type virus. (ii) The alteration in electrophoretic mobility of ICP0 made in cells infected with DeltaUL13 virus was due to the absence of the UL13 protein and not to failure of posttranslational modification of Deltaalpha22/DeltaUS1.5 proteins inasmuch as the mobility of ICP0 in cells infected with Deltaalpha22/DeltaUS1.5 virus could not be differentiated from that of wild-type infected cells. (iii) ICP0 is extensively phosphorylated in infected cells even in the absence of UL13 protein. ICP0 is, however, a substrate for the UL13 kinase inasmuch as ICP0 was phosphorylated in mixtures of immune complexes of ICP0 and UL13. Complexes containing ICP0 only or infected cell lysate proteins reacting with preimmune serum from the rabbit immunized with UL13 protein failed to phosphorylate ICP0. (iv) In the absence of UL13, ICP22 is overproduced-an imbalance attributed to UL13. Thus, ICP22 regulates both the utilization of splice acceptor sites and the longevity of ICP0 mRNA (K. L. Carter and B. Roizman, 1996, Proc. Natl. Acad. Sci. USA 93, 12535-12540); UL13 is involved in the posttranslational modification of ICP0 and is required for both posttranslational processing and control of abundance of ICP22. PMID:9281521

  8. Successful transfer of plasmid DNA into in vitro cells transfected with an inorganic plasmid-Mg/Al-LDH nanobiocomposite material as a vector for gene expression

    NASA Astrophysics Data System (ADS)

    Jaffri Masarudin, Mas; Yusoff, Khatijah; Rahim, Raha Abdul; Zobir Hussein, Mohd

    2009-01-01

    The delivery of a full plasmid, encoding the green fluorescent protein gene into African monkey kidney (Vero3) cells, was successfully achieved using nanobiocomposites based on layered double hydroxides. This demonstrated the potential of using the system as an alternative DNA delivery vector. Intercalation of the circular plasmid DNA, pEGFP-N2, into Mg/Al-NO3- layered double hydroxides (LDH) was accomplished through anion exchange routes to form the nanobiocomposite material. The host was previously synthesized at the Mg2+ to Al3+ molar ratio Ri = 2 and subsequently intercalated with plasmid DNA. Size expansion of the interlamellae host from 8.8 Å in LDH to 42 Å was observed in the resulting nanobiocomposite, indicating stable hybridization of the plasmid DNA. The powder x-ray diffraction (PXRD) results, supplemented with Fourier-transform infrared (FTIR) spectroscopy, compositional and electrophoresis studies confirmed the encapsulation episode of the biomaterial. In order to elucidate the use of this resulting nanobiocomposite as a delivery vector, an MTT assay was performed to determine any cytotoxic effects of the host towards cells. The intercalated pEGFP-N2 anion was later successfully recovered through acidification with HNO3 after treatment with DNA-degrading enzymes, thus also showing the ability of the LDH host to protect the intercalated biomaterial from degradation. Cell transfection studies on Vero3 cells were then performed, where cells transfected with the nanobiocomposite exhibited fluorescence as early as 12 h post-treatment compared to naked delivery of the plasmid itself.

  9. Acid tolerance and gad mRNA levels of Escherichia coli O157:H7 grown in foods.

    PubMed

    Yokoigawa, Kumio; Takikawa, Akiko; Okubo, Yoko; Umesako, Seiichi

    2003-05-15

    We examined the acid tolerance and gad mRNA levels of Escherichia coli O157:H7 (three strains) and nonpathogenic E. coli (strains K12, W1485, and B) grown in foods. The E. coli cells (approximately 30,000 cells) were inoculated on the surface of 10 g of solid food samples (asparagus, broccoli, carrot, celery, cucumber, eggplant, ginger, green pepper, onion, potato, radish, tomato and beef) and in 10 ml of cow's milk, cultured statically at 10-25 degrees C for 1-14 days, and subjected to an acid challenge at 37 degrees C for 1 h in LB medium (pH 3.0). When grown at 20 and 25 degrees C in all foods, except for tomato and ginger, the strains showed a stationary-phase specific acid tolerance. The acid tolerance of the O157 strains changed depending on the types of foods (3-10% survival), but was clearly lower than that of the cells grown in EC medium (more than 90% survival). Tomato and ginger induced relatively high acid tolerances (10-30% survival) in the O157 strains irrespective of the growth phase, probably because of their acidity. No remarkable difference was observed in the acid tolerance between the O157 and nonpathogenic strains grown in all foods. When grown at 10 and 15 degrees C in the foods and EC medium, none of the strains showed the stationary-phase specific acid tolerance. In beef, broccoli, celery, potato and radish, the acid tolerance showed a tendency to decrease with the prolonged cultivation time. In other foods, the acid tolerance was almost constant (about 0.1% survival) irrespective of the growth stage. The mRNA level of glutamate decarboxylase genes (gadA and gadB) correlated to the acid tolerance level when the E. coli cells were grown at 25 degrees C, but was very low even in the stationary phase when the E. coli cells were grown at 15 degrees C or below. PMID:12593923

  10. Tyrosyl kinases acquired from anchorage-independent cells by a membrane- enveloped virus

    Microsoft Academic Search

    G. M. Clinton; JOELLE FINLEY-WHELAN

    1984-01-01

    Tyrosyl kinase activity in vesicular stomatitis virus (VSV) acquired from host cells that differ in morphology was investigated. VSV grown in baby hamster kidney (BHK) cells with rounded morphology and a high efficiency of colony formation in soft agar (Rous sarcoma virus (RSV)-transformed and suspension BHK cells) was compared with VSV grown in BHK cells with a flattened morphology and

  11. Heart tissue grown in NASA Bioreactor

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Lisa Freed and Gordana Vunjak-Novakovic, both of the Massachusetts Institute of Technology (MIT), have taken the first steps toward engineering heart muscle tissue that could one day be used to patch damaged human hearts. Cells isolated from very young animals are attached to a three-dimensional polymer scaffold, then placed in a NASA bioreactor. The cells do not divide, but after about a week start to cornect to form a functional piece of tissue. Functionally connected heart cells that are capable of transmitting electrical signals are the goal for Freed and Vunjak-Novakovic. Electrophysiological recordings of engineered tissue show spontaneous contractions at a rate of 70 beats per minute (a), and paced contractions at rates of 80, 150, and 200 beats per minute respectively (b, c, and d). The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. 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. 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 MIT.

  12. Effect of dilution rate on lipopolysaccharide and serum resistance of Neisseria gonorrhoeae grown in continuous culture.

    PubMed Central

    Morse, S A; Mintz, C S; Sarafian, S K; Bartenstein, L; Bertram, M; Apicella, M A

    1983-01-01

    Growth of Neisseria gonorrhoeae strain FA171 in continuous culture under glucose-limiting conditions resulted in a growth-rate-dependent change in the lipopolysaccharide (LPS). The evidence for this change is an alteration in the mobility of purified alkali-treated LPS on sodium dodecyl sulfate-polyacrylamide gels and a quantitative difference in the amount of the LPS serotype antigen. The LPS from cells grown at a low dilution rate (0.12 h-1) contained ca. eightfold less serotype antigen than the LPS from cells grown at a high dilution rate (0.56 h-1). The decrease in LPS serotype antigen was associated with an increase in sensitivity to the bactericidal activity of normal human serum and an increase in cell surface hydrophobicity. An increase in the amount of serotype antigen was associated with a reduction in the accessibility of a monoclonal antibody to a core LPS determinant, an increase in resistance to normal human serum, and a decrease in cell surface hydrophobicity. The microheterogeneity of gonococcal LPS with respect to the content of serotype antigen may result from an alteration in the metabolism of glucose. Images PMID:6408006

  13. The NS3 protein of rice hoja blanca virus suppresses RNA silencing in mammalian cells.

    PubMed

    Schnettler, Esther; Hemmes, Hans; Goldbach, Rob; Prins, Marcel

    2008-01-01

    The NS3 protein of the tenuivirus rice hoja blanca virus (RHBV) has previously been shown to represent the viral RNA interference (RNAi) suppressor and is active in both plant and insect cells by binding short interfering RNAs (siRNAs) in vitro. Using a firefly luciferase-based silencing assay it is described here that NS3 is also active in mammalian cells. This activity is independent of the inducer molecule used. Using either synthetic siRNAs or a short hairpin RNA construct, NS3 was able to significantly suppress the RNAi-mediated silencing of luciferase expression in both monkey (Vero) and human (HEK293) cells. These results support the proposed mode of action of NS3 to act by sequestering siRNAs, the key molecules of the RNAi pathway conserved in all eukaryotes. The possible applications of this protein in modulating RNAi and investigating the proposed antiviral RNAi response in mammalian cell systems are discussed. PMID:18089758

  14. Herpesvirus simiae (B virus): replication of the virus and identification of viral polypeptides in infected cells.

    PubMed

    Hilliard, J K; Eberle, R; Lipper, S L; Munoz, R M; Weiss, S A

    1987-01-01

    The events and products of replication of Herpesvirus simiae (B virus) in Vero cells were studied. The time course of the synthetic events of DNA replication and protein synthesis were found to be similar to the processes of the herpes simplex viruses and SA 8. Infectious progeny virus were detected by 4 hours post infection and were first found extracellularly between 6 and 8 hours post infection (PI). As in the case of SA 8, all cell lines tested were permissive for lytic infection by B virus. Analyses of B virus-infected cells by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) revealed approximately 50 infected cell polypeptides (ICP) ranging in molecular weight from about 26,000 to 239,000 daltons. The kinetics of synthesis of the ICPs were also identified. At least nine glucosamine-containing glycopeptides were noted ranging from 133,000 to 29,000 daltons. PMID:3030236

  15. Carbon Nanotube Microarrays Grown on Nanoflake Substrates

    NASA Technical Reports Server (NTRS)

    Schmidt, Howard K.; Hauge, Robert H.; Pint, Cary; Pheasant, Sean

    2013-01-01

    This innovation consists of a new composition of matter where single-walled carbon nanotubes (SWNTs) are grown in aligned arrays from nanostructured flakes that are coated in Fe catalyst. This method of growth of aligned SWNTs, which can yield well over 400 percent SWNT mass per unit substrate mass, exceeds current yields for entangled SWNT growth. In addition, processing can be performed with minimal wet etching treatments, leaving aligned SWNTs with superior properties over those that exist in entangled mats. The alignment of the nanotubes is similar to that achieved in vertically aligned nanotubes, which are called "carpets. " Because these flakes are grown in a state where they are airborne in a reactor, these flakes, after growing SWNTs, are termed "flying carpets. " These flakes are created in a roll-to-roll evaporator system, where three subsequent evaporations are performed on a 100-ft (approx. =30-m) roll of Mylar. The first layer is composed of a water-soluble "release layer, " which can be a material such as NaCl. After depositing NaCl, the second layer involves 40 nm of supporting layer material . either Al2O3 or MgO. The thickness of the layer can be tuned to synthesize flakes that are larger or smaller than those obtained with a 40-nm deposition. Finally, the third layer consists of a thin Fe catalyst layer with a thickness of 0.5 nm. The thickness of this layer ultimately determines the diameter of SWNT growth, and a layer that is too thick will result in the growth of multiwalled carbon nanotubes instead of single-wall nanotubes. However, between a thickness of 0.5 nm to 1 nm, single-walled carbon nanotubes are known to be the primary constituent. After this three-layer deposition process, the Mylar is rolled through a bath of water, which allows catalyst-coated flakes to detach from the Mylar. The flakes are then collected and dried. The method described here for making such flakes is analogous to that which is used to make birefringent ink that is coated on U.S. currency. After deposition, the growth is carried out in a hot-filament chemical vapor deposition apparatus. A tungsten hot filament placed in the flow of H2 at a temperature greater than 1,600 C creates atomic hydrogen, which serves to reduce the Fe catalyst into a metallic state. The catalyst can now precipitate SWNTs in the presence of growth gases. The gases used for the experiments reported are C2H2, H2O, and H2, at rates of 2, 2, and 400 standard cubic centimeters per minute (sccm), respectively. In order to retain the flakes, a cage is constructed by spot welding stainless steel or copper mesh to form an enclosed area, in which the flakes are placed prior to growth. This allows growth gases and atomic hydrogen to reach the flakes, but does not allow the flakes, which rapidly nucleate SWNTs, to escape from the cage.

  16. Diamond films grown from fullerene precursors

    SciTech Connect

    Gruen, D.M.; Zuiker, C.D.; Krauss, A.R.

    1995-07-01

    Fullerene precursors have been shown to result in the growth of diamond films from argon microwave plasmas. In contradistinction to most diamond films grown using conventional methane-hydrogen mixtures, the fullerene-generated films are nanocrystalline and smooth on the nanometer scale. They have recently been shown to have friction coefficients approaching the values of natural diamond. It is clearly important to understand the development of surface morphology during film growth from fullerene precursors and to elucidate the factors leading to surface roughness when hydrogen is present in the chemical vapor deposition (CVD) gas mixtures. To achieve these goals, we are measuring surface reflectivity of diamond films growing on silicon substrates over a wide range of plasma processing conditions. A model for the interpretation of the laser interferometric data has been developed, which allows one to determine film growth rate, rms surface roughness, and bulk losses due to scattering and absorption. The rms roughness values determined by reflectivity are in good agreement with atomic force microscope (AFM) measurements. A number of techniques, including high-resolution transmission electron microscopy (HRTEM) and near-edge x-ray absorption find structure (NEXAFS) measurements, have been used to characterize the films. A mechanism for diamond-film growth involving the C{sub 2} molecule as a growth species will be presented. The mechanism is based on (1) the observation that the optical emission spectra of the fullerene- containing plasmas are dominated by the Swan bands of C{sub 2} and (2) the ability of C{sub 2} to insert directly into C-H and C-C bonds with low activation barriers, as shown by recent theoretical calculations of reactions of C{sub 2} with carbon clusters.

  17. 7 CFR 989.157 - Raisins produced from grapes grown outside of California.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Raisins produced from grapes grown outside of California. 989...OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN IN CALIFORNIA Administrative Rules... § 989.157 Raisins produced from grapes grown outside of California....

  18. 7 CFR 989.157 - Raisins produced from grapes grown outside of California.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Raisins produced from grapes grown outside of California. 989...OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN IN CALIFORNIA Administrative Rules... § 989.157 Raisins produced from grapes grown outside of California....

  19. 7 CFR 989.157 - Raisins produced from grapes grown outside of California.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Raisins produced from grapes grown outside of California. 989...OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN IN CALIFORNIA Administrative Rules... § 989.157 Raisins produced from grapes grown outside of California....

  20. 7 CFR 989.157 - Raisins produced from grapes grown outside of California.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Raisins produced from grapes grown outside of California. 989...OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN IN CALIFORNIA Administrative Rules... § 989.157 Raisins produced from grapes grown outside of California....

  1. 7 CFR 989.157 - Raisins produced from grapes grown outside of California.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Raisins produced from grapes grown outside of California. 989...OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN IN CALIFORNIA Administrative Rules... § 989.157 Raisins produced from grapes grown outside of California....

  2. 78 FR 24981 - Irish Potatoes Grown in Washington; Decreased Assessment Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-29

    ...AMS-FV-13-0010; FV13-946-1 IR] Irish Potatoes Grown in Washington; Decreased...which regulates the handling of Irish potatoes grown in Washington. Assessments...regulating the handling of Irish potatoes grown in Washington,...

  3. 78 FR 48285 - Irish Potatoes Grown in Washington; Decreased Assessment Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-08

    ...AMS-FV-13-0010; FV13-946-1 FIR] Irish Potatoes Grown in Washington; Decreased...administers the marketing order for Irish potatoes grown in Washington. Decreasing...regulating the handling of Irish potatoes grown in Washington,...

  4. 76 FR 18001 - Irish Potatoes Grown in Washington; Decreased Assessment Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-01

    ...AMS-FV-11-0012; FV11-946-2 IR] Irish Potatoes Grown in Washington; Decreased...which regulates the handling of Irish potatoes grown in Washington. Assessments...regulating the handling of Irish potatoes grown in Washington,...

  5. Heart tissue grown in NASA Bioreactor

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Lisa Freed and Gordana Vunjak-Novakovic, both of the Massachusetts Institute of Technology (MIT), have taken the first steps toward engineering heart muscle tissue that could one day be used to patch damaged human hearts. Cells isolated from very young animals are attached to a three-dimensional polymer scaffold, then placed in a NASA bioreactor. The cells do not divide, but after about a week start to cornect to form a functional piece of tissue. Here, a transmission electron micrograph of engineered tissue shows a number of important landmarks present in functional heart tissue: (A) well-organized myofilaments (Mfl), z-lines (Z), and abundant glycogen granules (Gly); and (D) intercalcated disc (ID) and desmosomes (DES). The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. 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. 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: MIT

  6. The effects of confluency on cell mechanical properties.

    PubMed

    Efremov, Yu M; Dokrunova, A A; Bagrov, D V; Kudryashova, K S; Sokolova, O S; Shaitan, K V

    2013-04-01

    Mechanical properties of cells depend on various external and internal factors, like substrate stiffness and surface modifications, cell ageing and disease state. Some other currently unknown factors may exist. In this study we used force spectroscopy by AFM, confocal microscopy and flow cytometry to investigate the difference between single non-confluent and confluent (in monolayer) Vero cells. In all cases the stiffness values were fitted by log-normal rather than normal distribution. Log-normal distribution was also found for an amount of cortical actin in cells by flow cytometry. Cells in the monolayer were characterized by a significantly lower (1.4-1.7 times) Young's modulus and amount of cortical actin than in either of the single non-confluent cells or cells migrating in the experimental wound. Young's modulus as a function of indentation speed followed a weak power law for all the studied cell states, while the value of the exponent was higher for cells growing in monolayer. These results show that intercellular contacts and cell motile state significantly influence the cell mechanical properties. PMID:23453395

  7. Method for fabricating silicon cells

    DOEpatents

    Ruby, D.S.; Basore, P.A.; Schubert, W.K.

    1998-08-11

    A process is described for making high-efficiency solar cells. This is accomplished by forming a diffusion junction and a passivating oxide layer in a single high-temperature process step. The invention includes the class of solar cells made using this process, including high-efficiency solar cells made using Czochralski-grown silicon. 9 figs.

  8. Method for fabricating silicon cells

    DOEpatents

    Ruby, Douglas S. (Albuquerque, NM); Basore, Paul A. (Albuquerque, NM); Schubert, W. Kent (Albuquerque, NM)

    1998-08-11

    A process for making high-efficiency solar cells. This is accomplished by forming a diffusion junction and a passivating oxide layer in a single high-temperature process step. The invention includes the class of solar cells made using this process, including high-efficiency solar cells made using Czochralski-grown silicon.

  9. Cryopreservation of in vitro grown shoot tips

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter in Plant Cell Culture, Development and Biotechnology describes student laboratory exercises for cryopreservation of the growing shoot tips of plants in liquid nitrogen. It includes two exercises involving step by step protocols for use with shoot tips. Vitrification (fast freezing) an...

  10. Nanotransfer and nanoreplication using deterministically grown sacrificial nanotemplates

    SciTech Connect

    Melechko, Anatoli V. (Oak Ridge, TN); McKnight, Timothy E. (Greenback, TN); Guillorn, Michael A. (Ithaca, NY); Ilic, Bojan (Ithaca, NY); Merkulov, Vladimir I. (Knoxville, TN); Doktycz, Mitchel J. (Knoxville, TN); Lowndes, Douglas H. (Knoxville, TN); Simpson, Michael L. (Knoxville, TN)

    2011-08-23

    Methods, manufactures, machines and compositions are described for nanotransfer and nanoreplication using deterministically grown sacrificial nanotemplates. An apparatus, includes a substrate and a nanoreplicant structure coupled to a surface of the substrate.

  11. GUIDELINES AND ACCEPTABLE POSTHARVEST PRACTICES FOR ORGANICALLY GROWN PRODUCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic foods are produced using agricultural practices that emphasize renewable resources and conservation of soil and water. Horticultural crops are grown and processed without synthetic fertilizers, pesticides, ingredients and processing aids. Crops or ingredients derived from genetic engineeri...

  12. Survival of Potentially Pathogenic Human-Associated Bacteria in the Rhizosphere of Hydroponically Grown Wheat

    NASA Technical Reports Server (NTRS)

    Morales, Anabelle; Garland, Jay L.; Lim, Daniel V.

    1996-01-01

    Plants may serve as reservoirs for human-associated bacteria (H-AB) in long-term space missions containing bioregenerative life support systems. The current study examined the abilities of five human-associated potential pathogens, Pseudomonas aeruginosa, Pseudomonas cepacia, Staphylococcus aureus, Streptococcus pyogenes, and Escherichia coli, to colonize and grow in the rhizosphere of hydroponically grown wheat, a candidate crop for life support. All of these bacteria have been recovered from past NASA missions and present potential problems for future missions. The abilities of these organisms to adhere to the roots of axenic five-day-old wheat (Triticum aestivum L. cv. Yecora rojo) were evaluated by enumeration of the attached organisms after a one hour incubation of roots in a suspension (approximately 10(exp 8 cu/ml)) of the H-AB. Results showed that a greater percentage of P. aeruginosa cells adhered to the wheat roots than the other four H-AB. Similarly incubated seedlings were also grown under attempted axenic conditions for seven days to examine the potential of each organism to proliferate in the rhizosphere (root colonization capacity). P. cepacia and P. aeruginosa showed considerable growth. E. coli and S. aureus showed no significant growth, and S. pyogenes died off in the wheat rhizosphere. Studies examining the effects of competition on the survival of these microorganisms indicated that P. aeruginosa was the only organism that survived in the rhizosphere of hydroponically grown wheat in the presence of different levels of microbial competition.

  13. Sizing Up the Cell

    NSDL National Science Digital Library

    Bruce Edgar (Fred Hutchinson Cancer Research Center; )

    2009-07-10

    This perspective discusses new information and experimental methods used in the study of the kinetics of cell growth and its influence on cell division. The coordination of cell growth and division is responsible for fundamental characteristics of cells such as their size: Fast growth with slow division makes big cells, whereas slow growth with fast division makes small cells. Yet despite decades of effort, the kinetics of cell growth and its influence on cell division have remained elusive topics, at least for animal cells. Is cell growth linear (constant) or exponential (proportional to cell size)? Does cell division occur after cells have grown beyond a minimum size, or is there rather some â??age of consentâ? for division, or both? A report by Tzur et al. combines a new experimental method with careful mathematical analysis to answer these questions for cultured mammalian lymphoblasts.

  14. Retargeting Clostridium difficile Toxin B to Neuronal Cells as a Potential Vehicle for Cytosolic Delivery of Therapeutic Biomolecules to Treat Botulism

    PubMed Central

    Krautz-Peterson, Greice; Zhang, Yongrong; Chen, Kevin; Oyler, George A.; Feng, Hanping; Shoemaker, Charles B.

    2012-01-01

    Botulinum neurotoxins (BoNTs) deliver a protease to neurons which can cause a flaccid paralysis called botulism. Development of botulism antidotes will require neuronal delivery of agents that inhibit or destroy the BoNT protease. Here, we investigated the potential of engineering Clostridium difficile toxin B (TcdB) as a neuronal delivery vehicle by testing two recombinant TcdB chimeras. For AGT-TcdB chimera, an alkyltransferase (AGT) was appended to the N-terminal glucosyltransferase (GT) of TcdB. Recombinant AGT-TcdB had alkyltransferase activity, and the chimera was nearly as toxic to Vero cells as wild-type TcdB, suggesting efficient cytosolic delivery of the AGT/GT fusion. For AGT-TcdB-BoNT/A-Hc, the receptor-binding domain (RBD) of TcdB was replaced by the equivalent RBD from BoNT/A (BoNT/A-Hc). AGT-TcdB-BoNT/A-Hc was >25-fold more toxic to neuronal cells and >25-fold less toxic to Vero cells than AGT-TcdB. Thus, TcdB can be engineered for cytosolic delivery of biomolecules and improved targeting of neuronal cells. PMID:21941543

  15. Steady state protein levels in Geobacter metallireducens grown with Iron (III) citrate or nitrate as terminal electron acceptor.

    SciTech Connect

    Ahrendt, A. J.; Tollaksen, S. L.; Lindberg, C.; Zhu, W.; Yates, J. R., III; Nevin, K. P.; Lovley, D.; Giometti, C. S.; Biosciences Division; The Scripps Research Inst.; Univ. of Massachusetts

    2007-01-01

    Geobacter species predominate in aquatic sediments and submerged soils where organic carbon sources are oxidized with the reduction of Fe(III). The natural occurrence of Geobacter in some waste sites suggests this microorganism could be useful for bioremediation if growth and metabolic activity can be regulated. 2-DE was used to monitor the steady state protein levels of Geobacter metallireducens grown with either Fe(III) citrate or nitrate to elucidate metabolic differences in response to different terminal electron acceptors present in natural environments populated by Geobacter. Forty-six protein spots varied significantly in abundance (p<0.05) between the two growth conditions; proteins were identified by tryptic peptide mass and peptide sequence determined by MS/MS. Enzymes involved in pyruvate metabolism and the tricarboxylic acid (TCA) cycle were more abundant in cells grown with Fe(III) citrate, while proteins associated with nitrate metabolism and sensing cellular redox status along with several proteins of unknown function were more abundant in cells grown with nitrate. These results indicate a higher level of flux through the TCA cycle in the presence of Fe(III) compared to nitrate. The oxidative stress response observed in previous studies of Geobacter sulfurreducens grown with Fe(III) citrate was not seen in G. metallireducens.

  16. Large-scale defect accumulations in Czochralski-grown silicon

    Microsoft Academic Search

    V. P. Kalinushkin; A. N. Buzynin; V. A. Yuryev; O. V. Astafiev

    2011-01-01

    Czochralski-grown silicon crystals were studied by the techniques of the low-angle mid-IR-light scattering and electron-beam-induced current. The large-scale accumulations of electrically-active impurities detected in this material were found to be different in their nature and formation mechanisms from the well-known impurity clouds in a FZ-grown silicon. A classification of the large-scale impurity accumulations in CZ Si is made and point

  17. Photoemission electronic states of epitaxially grown magnetite films

    Microsoft Academic Search

    R. Zalecki; A. Ko?odziejczyk; J. Korecki; N. Spiridis; M. Zaj?c; A. Koz?owski; Z. K?kol; D. Antolak

    2007-01-01

    The valence band photoemission spectra of epitaxially grown 300? single crystalline magnetite films were measured by the angle-resolved ultraviolet photoemission spectroscopy (ARUPS) at 300K. The samples were grown either on MgO(001) (B termination) or on (001) Fe (iron-rich A termination), thus intentionally presenting different surface stoichiometry, i.e. also different surface electronic states. Four main features of the electron photoemission at

  18. Thermal behaviour of strontium tartrate single crystals grown in gel

    Microsoft Academic Search

    M. H. Rahimkutty; K. Rajendra Babu; K. Sreedharan Pillai; M. R. Sudarsana Kumar; C. M. K. Nair

    2001-01-01

    Thermal behaviour of strontium tartrate crystals grown with the aid of sodium metasilicate gel is investigated using thermogravimetry\\u000a (TG) and differential thermal analysis (DTA). Effect of magnetic field and dopant (Pb)2+ on the crystal stability is also studied using thermal analysis. This study reveals that water molecules are locked up in\\u000a the lattice with different strengths in the grown crystals.

  19. Glycolate metabolism in low and high CO sub 2 -grown chlorella pyrenoidosa and Pavlova lutheri as determined by sup 18 O-labeling

    SciTech Connect

    de Veau, E.J.; Burris, J.E. (Pennsylvania State Univ., University Park (USA))

    1989-11-01

    Photorespiration in Chlorella pyrenoidosa Chick. was assayed by measuring {sup 18}O-labeled intermediates of the glycolate pathway. Glycolate, glycine, serine, and excreted glycolate were isolated and analyzed on a gas chromatograph/mass spectrometer to determine isotopic enrichment. Rates of glycolate synthesis were determined from {sup 18}O-labeling kinetics of the intermediates, pool sizes, derived rate equations, and nonlinear regression techniques. Glycolate synthesis was higher in high CO{sub 2}-grown cells than in air-grown cells when both were assayed under the same O{sub 2} and CO{sub 2} concentrations. Synthesis of glycolate, for both types of cells, was stimulated by high O{sub 2} levels and inhibited by high CO{sub 2} levels. Glycolate synthesis in 1.5% CO{sub 2}-grown Chlorella, when exposed to a 0.035% CO{sub 2} atmosphere, increased from about 41 to 86 nanomoles per milligram chlorophyll per minute when the O{sub 2} concentration was increased from 21 to 40%. Glycolate synthesis in air-grown cells increased from 2 to 6 nanomoles per milligram chlorophyll per minute under the same gas levels. Synthesis was undetectable when either the O{sub 2} concentration was lowered to 2% or the CO{sub 2}-concentration was raised to 1.5%. Glycolate excretion was also sensitive to O{sub 2} and CO{sub 2} concentrations in 1.5% CO{sub 2}-grown cells and the glycolate that was excreted was {sup 18}O-labeled. Air-grown cells did not excrete glycolate under any experimental condition. Indirect evidence indicated that glycolate may be excreted as a lactone in Chlorella. Photorespiratory {sup 18}O-labeling kinetics were determined for Pavlova lutheri, which unlike Chlorella and higher plants did not directly synthesize glycine and serine from glycolate. This alga did excrete a significant proportion of newly synthesized glycolate into the media.

  20. Defect Density Characterization of Detached-Grown Germanium Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Cobb, S. D.; Volz, M. P.; Szoke, J.; Szofran, F. R.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Several (111)-oriented, Ga-doped germanium crystals were grown in pyrolytic boron nitride (pBN) containers by the Bridgman and the detached Bridgman growth techniques. Growth experiments in closed-bottom pBN containers resulted in nearly completely detached-grown crystals, because the gas pressure below the melt can build up to a higher pressure than above the melt. With open-bottom tubes the gas pressure above and below the melt is balanced during the experiment, and thus no additional force supports the detachment. In this case the crystals grew attached to the wall. Etch pit density (EPD) measurements along the axial growth direction indicated a strong improvement of the crystal quality of the detached-grown samples compared to the attached samples. Starting in the seed with an EPD of 6-8 x 10(exp 3)/square cm it decreased in the detached-grown crystals continuously to about 200-500/square cm . No significant radial difference between the EPD on the edge and the middle of the crystal exists. In the attached grown samples the EPD increases up to a value of about 2-4 x 10(exp 4)/square cm (near the edge) and up to 1 x 10(exp 4)/square cm in the middle of the sample. Thus the difference between the detached- and the attached-grown crystals with respect to the EPD is approximately two orders of magnitude.

  1. Comparative effectiveness of a clinostat and a slow-turning lateral vessel at mimicking the ultrastructural effects of microgravity in plant cells

    NASA Technical Reports Server (NTRS)

    Moore, R.

    1990-01-01

    The object of this research was to determine how effectively the actions of a clinostat and a fluid-filled, slow-turning lateral vessel (STLV) mimic the ultrastructural effects of microgravity in plant cells. We accomplished this by qualitatively and quantitatively comparing the ultrastructures of cells grown on clinostats and in an STLV with those of cells grown at 1 g and in microgravity aboard the Space Shuttle Columbia. Columella cells of Brassica perviridis seedlings grown in microgravity and in an STLV have similar structures. Both contain significantly more lipid bodies, less starch, and fewer dictyosomes than columella cells of seedlings grown at 1 g. Cells of seedlings grown on clinostats have significantly different ultrastructures from those grown in microgravity or in an STLV, indicating that clinostats do not mimic microgravity at the ultrastructural level. The similar structures of columella cells of seedlings grown in an STLV and in microgravity suggest that an STLV effectively mimics microgravity at the ultrastructural level.

  2. Synthesis and characterization of pectin derivative with antitumor property against Caco-2 colon cancer cells.

    PubMed

    Almeida, Elizângela A M S; Facchi, Suelen P; Martins, Alessandro F; Nocchi, Samara; Schuquel, Ivânia T A; Nakamura, Celso V; Rubira, Adley F; Muniz, Edvani C

    2015-01-22

    New pectin derivative (Pec-MA) was obtained in specific reaction conditions. The presence of maleoyl groups in Pec-MA structure was confirmed by (1)H NMR and FTIR spectroscopy. The substitution degree of Pec-MA (DS=24%) was determined by (1)H NMR. The properties of Pec-MA were investigated through WAXS, TGA/DTG, SEM and zeta potential techniques. The Pec-MA presented amorphous characteristics and higher-thermal stability compared to raw pectin (Pec). In addition, considerable morphological differences between Pec-MA and Pec were observed by SEM. The cytotoxic effect on the Caco-2 cells showed that the Pec-MA significantly inhibited the growth of colon cancer cells whereas the Pec-MA does not show any cytotoxic effect on the VERO healthy cells. This result opens new perspectives for the manufacture of biomaterials based on Pec with anti-tumor properties. PMID:25439878

  3. Stability of the glycoprotein gene of avian metapneumovirus (Canada goose isolate 15a/01) after serial passages in cell cultures.

    PubMed

    Chockalingam, Ashok K; Chander, Yogesh; Halvorson, David A; Goyal, Sagar M

    2010-06-01

    The glycoprotein (G) gene sequences of avian metapneumovirus (aMPV) subtypes A, B, C, and D are variable in size and number of nucleotides. The G gene of early U.S. turkey isolates of aMPV-C have been reported to be 1798 nucleotides (nt) (585 aa) in length, whereas the G genes of more recent turkey isolates have been reported to be 783 nucleotides. In some studies, the G gene of aMPV-C turkey isolates was found to be truncated to a smaller G gene of 783 nt (261 aa) upon serial passages in Vero cells. This is believed to be due to the deletion of 1015 nt near the end of the open reading frame. The purpose of this study was to determine variation, if any, in the G gene of an aMPV-C isolated from a wild bird (Canada goose [Branta canadensis]) following serial passages in Vero cells. No size variation was observed for up to 50 passages, except for a few amino acid changes in the extracellular domain at the 50th passage level. The G gene of this wild bird isolate appears to be unique from subtype C metapneumoviruses of turkeys. PMID:20608539

  4. Usutu virus growth in human cell lines: induction of and sensitivity to type I and III interferons.

    PubMed

    Scagnolari, Carolina; Caputo, Beniamino; Trombetti, Simona; Cacciotti, Giulia; Soldà, Annalisa; Spano, Lucia; Villari, Paolo; della Torre, Alessandra; Nowotny, Norbert; Antonelli, Guido

    2013-04-01

    The mechanisms of Usutu virus (USUV) pathogenesis are largely unknown. The aim of this study was to evaluate the sensitivity of USUV to interferon (IFN) and the capacity of USUV to stimulate IFN production. Initial experiments were conducted to characterize the susceptibility of human cell lines to USUV infection and to evaluate the single-growth cycle replication curve of USUV. Results indicate that USUV is able to infect a variety of human cell lines, completing the replication cycle in Hep-2 and Vero cells within 48 h. Pre-treatment of cells with types I and III IFNs significantly inhibited the replication of USUV. However, the inhibitory effects of IFNs were considerably less if IFN was added after viral infection had been initiated. Also, USUV weakly induced types I and III IFNs. PMID:23255619

  5. Comparative Studies on Cellular Behaviour of Carnation (Dianthus caryophyllus Linn. cv. Grenadin) Grown In Vivo and In Vitro for Early Detection of Somaclonal Variation

    PubMed Central

    Yaacob, Jamilah Syafawati; Taha, Rosna Mat; Khorasani Esmaeili, Arash

    2013-01-01

    The present study deals with the cytological investigations on the meristematic root cells of carnation (Dianthus caryophyllus Linn.) grown in vivo and in vitro. Cellular parameters including the mitotic index (MI), chromosome count, ploidy level (nuclear DNA content), mean cell and nuclear areas, and cell doubling time (Cdt) were determined from the 2?mm root tip segments of this species. The MI value decreased when cells were transferred from in vivo to in vitro conditions, perhaps due to early adaptations of the cells to the in vitro environment. The mean chromosome number was generally stable (2n = 2x = 30) throughout the 6-month culture period, indicating no occurrence of early somaclonal variation. Following the transfer to the in vitro environment, a significant increase was recorded for mean cell and nuclear areas, from 26.59 ± 0.09??m2 to 35.66 ± 0.10??m2 and 142.90 ± 0.59??m2 to 165.05 ± 0.58??m2, respectively. However, the mean cell and nuclear areas of in vitro grown D. caryophyllus were unstable and fluctuated throughout the tissue culture period, possibly due to organogenesis or rhizogenesis. Ploidy level analysis revealed that D. caryophyllus root cells contained high percentage of polyploid cells when grown in vivo and maintained high throughout the 6-month culture period. PMID:23766703

  6. Low temperature-induced accumulation of eicosapentaenoic acids in Marchantia polymorpha cells

    Microsoft Academic Search

    Makoto Saruwatari; Susumu Takio; Kanji Ono

    1999-01-01

    The composition of fatty acids in suspension-cultured cells from the liverwort Marchantia polymorpha L. grown at 25 and 15°C was analyzed. The liverwort cells grown at 25°C contained approximately 18% linolenic acid (18:3?3), 11% arachidonic acid (20:4?6) and 3% eicosapentaenoic acid (20:5?3) as percentages of total fatty acids. When the cells were grown at 15°C, the relative amounts of 18:3

  7. Defect studies in 4H- Silicon Carbide PVT grown bulk crystals, CVD grown epilayers and devices

    NASA Astrophysics Data System (ADS)

    Byrappa, Shayan M.

    Silicon Carbide [SiC] which exists as more than 200 different polytypes is known for superior high temperature and high power applications in comparison to conventional semiconductor materials like Silicon and Germanium. The material finds plethora of applications in a diverse fields due to its unique properties like large energy bandgap, high thermal conductivity and high electric breakdown field. Though inundated with superior properties the potential of this material has not been utilized fully due to impeding factors such as defects especially the crystalline ones which limit their performance greatly. Lots of research has been going on for decades to reduce these defects and there has been subsequent improvement in the quality as the diameter of SiC commercial wafers has reached 150mm from 25mm since its inception. The main focus of this thesis has been to study yield limiting defect structures in conjunction with several leading companies and national labs using advanced characterization tools especially the Synchrotron source. The in depth analysis of SiC has led to development of strategies to reduce or eliminate the density of defects by studying how the defects nucleate, replicate and interact in the material. The strategies discussed to reduce defects were proposed after careful deliberation and analysis of PVT grown bulk crystals and CVD grown epilayers. Following are some of the results of the study: [1] Macrostep overgrowth mechanism in SiC was used to study the deflection of threading defects onto the basal plane resulting in stacking faults. Four types of stacking faults associated with deflection of c/c+a threading defects have been observed to be present in 76mm, 100mm and 150mm diameter wafers. The PVT grown bulk crystals and CVD grown epilayers in study were subjected to contrast studies using synchrotron white beam X-ray topography [SWBXT]. The SWBXT image contrast studies of these stacking faults with comparison of calculated phase shifts for postulated fault vectors by macrostep overgrowth of surface outcrops, has revealed faults to be of four types of which one of the following are discussed in detail which is the Shockley faults. The fault vector were determined by taking into account the contrast from stacking faults in SWBXT undergoing phase shift as the X-ray wave fields cross the fault plane. The deflected dislocations onto the basal plane were responsible for the stacking faults and were observed to be detrimental to the devices grown on them as they replicate to the epilayer. In the wafers studied at different stages of the SiC crystal boule resulted in reduction of threading defects as they at certain stage get deflected out of the crystal causing drop of defects density. [2] A novel technique known as the Ray Tracing Simulation was used to determine the sense of c/c+a dislocations obtained via Grazing-Incidence X-ray Topography. Determination of the complete sense and burgers vector of these dislocations was very important to augment our proposed models on stacking faults associated with these defects. Orientation contrast mechanism in X- ray diffraction topography was previously determined to be the dominant factor in SiC by our group and the same principles were used for the simulation. The results were surmised after extensive comparison between experimental and simulation images for the c+2a defects. [3] With the BPD density down to a record level of few hundred per square centimeter in several wafers in multiple regions made it possible to observe the conversion of sessile Threading Edge Dislocations [TED] to glissile BPDs with this repeating multiple times. Previously the high density of Basal Plane Dislocations [BPD] prevented from discerning the details accurately in the SiC images taken by SWBXT. The contribution of SWBXT in accurately categorizing the nature of dislocations in SiC has enabled the crystal growth community to incorporate strategies to mitigate their influence. One of them has been recognizing BPDs as deformation induced defects which have led to the development of

  8. YIELD COMPARISON OF INDICA AND US CULTIVARS GROWN IN THE SOUTHERN UNITED STATES AND BRAZIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two subspecies of cultivated rice (Oryza sativa L.) are indica, grown in tropical areas like southern China, and japonica, grown in temperate areas. Tropical japonicas are the japonica subgroup grown in the southern US. When indica rices are grown in the southern US and compared to tropical japoni...

  9. Radiation effects on p+n InP junctions grown by MOCVD

    NASA Technical Reports Server (NTRS)

    Messenger, Scott R.; Walters, Robert J.; Panunto, M. J.; Summers, Geoffrey P.

    1994-01-01

    The superior radiation resistance of InP over other solar cell materials such as Si or GaAs has prompted the development of InP cells for space applications. The early research on radiation effects in InP was performed by Yamaguchi and co-workers who showed that, in diffused p-InP junctions, radiation-induced defects were readily annealed both thermally and by injection, which was accompanied by significant cell recovery. More recent research efforts have been made using p-InP grown by metalorganic chemical vapor deposition (MOCVD). While similar deep level transient spectroscopy (DLTS) results were found for radiation induced defects in these cells and in diffused junctions, significant differences existed in the annealing characteristics. After injection annealing at room temperature, Yamaguchi noticed an almost complete recovery of the photovoltaic parameters, while the MOCVD samples showed only minimal annealing. In searching for an explanation of the different annealing behavior of diffused junctions and those grown by MOCVD, several possibilities have been considered. One possibility is the difference in the emitter structure. The diffused junctions have S-doped graded emitters with widths of approximately 0.3 micrometers, while the MOCVD emitters are often doped with Si and have widths of approximately 300A (0.03 micrometers). The difference in the emitter thickness can have important effects, e.g. a larger fraction of the total photocurrent is generated in the n-type material for thicker emitters. Therefore the properties of the n-InP material may explain the difference in the observed overall annealing behavior of the cells.

  10. Growth and photosynthetic responses of wheat plants grown in space

    NASA Technical Reports Server (NTRS)

    Tripathy, B. C.; Brown, C. S.; Levine, H. G.; Krikorian, A. D.

    1996-01-01

    Growth and photosynthesis of wheat (Triticum aestivum L. cv Super Dwarf) plants grown onboard the space shuttle Discovery for 10 d were examined. Compared to ground control plants, the shoot fresh weight of space-grown seedlings decreased by 25%. Postflight measurements of the O2 evolution/photosynthetic photon flux density response curves of leaf samples revealed that the CO2-saturated photosynthetic rate at saturating light intensities in space-grown plants declined 25% relative to the rate in ground control plants. The relative quantum yield of CO2-saturated photosynthetic O2 evolution measured at limiting light intensities was not significantly affected. In space-grown plants, the light compensation point of the leaves increased by 33%, which likely was due to an increase (27%) in leaf dark-respiration rates. Related experiments with thylakoids isolated from space-grown plants showed that the light-saturated photosynthetic electron transport rate from H2O through photosystems II and I was reduced by 28%. These results demonstrate that photosynthetic functions are affected by the microgravity environment.

  11. Seedborne fungal contamination: consequences in space-grown wheat

    NASA Technical Reports Server (NTRS)

    Bishop, D. L.; Levine, H. G.; Kropp, B. R.; Anderson, A. J.; Hood, E. E. (Principal Investigator)

    1997-01-01

    Plants grown in microgravity are subject to many environmental stresses that may promote microbial growth and result in disease symptoms. Wheat (cv. Super Dwarf) recovered from an 8-day mission aboard a NASA (National Aeronautics and Space Administration) space shuttle showed disease symptoms, including girdling of leaf sheaths and chlorosis and necrosis of leaf and root tissues. A Neotyphodium species was isolated from the seed and leaf sheaths of symptomatic wheat used in the spaceflight mission. Certain isozymes of a peroxidase unique to extracts from the microgravity-grown plants were observed in extracts from earth-grown Neotyphodium-infected plants but were not present in noninfected wheat. The endophytic fungus was eliminated from the wheat seed by prolonged heat treatment at 50 degrees C followed by washes with water at 50 degrees C. Plants from wheat seed infected with the Neotyphodium endophyte were symptomless when grown under greenhouse conditions, whereas symptoms appeared after only 4 days of growth in closed containers. Disease spread from an infected plant to noninfected plants in closed containers. Dispersion via spores was found on asymptomatic plants at distances of 7 to 18 cm from infected plants. The size and shape of the conidia, mycelia, and phialide-bearing structures and the ability to grow rapidly on carbohydrates, especially xylose, resembled the characteristics of N. chilense, which is pathogenic on orchard grass, Doctylis glomerati. The Neotyphodium wheat isolate caused disease symptoms on other cereals (wheat cv. Malcolm, orchard grass, barley, and maize) grown in closed containers.

  12. Oxygen Uptake and Hydrogen-Stimulated Nitrogenase Activity from Azorhizobium caulinodans ORS571 Grown in a Succinate-Limited Chemostat

    PubMed Central

    Allen, George C.; Grimm, Daniel T.; Elkan, Gerald H.

    1991-01-01

    Succinate-limited continuous cultures of an Azorhizobium caulinodans strain were grown on ammonia or nitrogen gas as a nitrogen source. Ammonia-grown cells became oxygen limited at 1.7 ?M dissolved oxygen, whereas nitrogen-fixing cells remained succinate limited even at dissolved oxygen concentrations as low as 0.9 ?M. Nitrogen-fixing cells tolerated dissolved oxygen concentrations as high as 41 ?M. Succinate-dependent oxygen uptake rates of cells from the different steady states ranged from 178 to 236 nmol min?1 mg of protein?1 and were not affected by varying chemostat-dissolved oxygen concentration or nitrogen source. When equimolar concentrations of succinate and ?-hydroxybutyrate were combined, oxygen uptake rates were greater than when either substrate was used alone. Azide could also used alone as a respiratory substrate regardless of nitrogen source; however, when azide was added following succinate additions, oxygen uptake was inhibited in ammonia-grown cells and stimulated in nitrogen-fixing cells. Use of 25 mM succinate in the chemostat resevoir at a dilution rate of 0.1 h?1 resulted in high levels of background respiration and nitrogenase activity, indicating that the cells were not energy limited. Lowering the reservoir succinate to 5 mM imposed energy limitation. Maximum succinate-dependent nitrogenase activity was 1,741 nmol of C2H4h?1 mg (dry weight)?1, and maximum hydrogen-dependent nitrogenase activity was 949 nmol of C2H4 h?1 mg (dry weight)?1. However, when concentration of 5% (vol/vol) hydrogen or greater were combined with succinate, nitrogenase activity decreased by 35% in comparison to when succinate was used alone. Substitution of argon for nitrogen in the chemostat inflow gas resulted in “washout,” proving that ORS571 can grow on N2 and that there was not a nitrogen source in the medium that could substitute. PMID:16348585

  13. Totipotency and embryogenesis in plant cell and tissue cultures

    Microsoft Academic Search

    Indira K. Vasil; Vimla Vasil

    1972-01-01

    Summary  An important development in the field of plant cell and tissue culture has been the demonstration in the past decade of the\\u000a totipotency of higher plant cells. Isolated single cells were first successfully grown on a nurse tissue separated by a filter\\u000a paper and gave rise to a callus tissue. Later, completely isolated single cells of tobacco were grown in

  14. Developing cell culture-derived pandemic vaccines.

    PubMed

    Barrett, P Noel; Portsmouth, Daniel; Ehrlich, Hartmut J

    2010-02-01

    The growing prospect of avian influenza viruses achieving sustained interhuman transmission, combined with the recent emergence of a novel swine-origin A/H1N1 influenza strain, has brought the issue of influenza vaccine production capacity into sharp focus. It is becoming increasingly clear that traditional egg-based manufacturing processes may be insufficient to meet global vaccine demands in a pandemic situation that is caused by a highly pathogenic influenza virus. This review introduces the concepts of modern, cell culture-derived influenza vaccines and their manufacture, and explains the advantages of these vaccines in terms of both speed and efficiency of production as well as immunogenic efficacy. Vaccine production technologies using the mammalian cell lines Vero, MDCK and PER.C6, as well as the baculovirus/insect cell platform, are described in detail. Clinical data are provided from cell culture-derived vaccines that are at an advanced stage of development, and insights are provided into recent developments in the preclinical evaluation of more experimental technologies. PMID:20140813

  15. Proton translocation coupled to dimethyl sulfoxide reduction in anaerobically grown Escherichia coli HB101

    SciTech Connect

    Bilous, P.T.; Weiner, J.H.

    1985-07-01

    Proton translocation coupled to dimethyl sulfoxide (DMSO) reduction was examined in Escherichia coli HB101 grown anaerobically on glycerol and DMSO. Rapid acidification of the medium was observed when an anaerobic suspension of cells, preincubated with glycerol, was pulsed with DMSO, methionine sulfoxide, nitrate, or trimethylamine N-oxide. The DMSO-induced acidification was sensitive to the uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone (60 microM) and was inhibited by the quinone analog 2-n-heptyl-4-hydroxy-quinoline-N-oxide (5.6 microM). Neither sodium azide nor potassium cyanide inhibited the DMSO response. An apparent----H+/2e- ratio of 2.9 was obtained for DMSO reduction with glycerol as the reductant. Formate and H2(g), but not lactate, could serve as alternate electron donors for DMSO reduction. Cells grown anaerobically on glycerol and fumarate displayed a similar response to pulses of DMSO, methionine sulfoxide, nitrate, and trimethylamine N-oxide with either glycerol or H2(g) as the electron donor. However, fumarate pulses did not result in acidification of the suspension medium. Proton translocation coupled to DMSO reduction was also demonstrated in membrane vesicles by fluorescence quenching. The addition of DMSO to hydrogen-saturated everted membrane vesicles resulted in a carbonyl cyanide p-trifluoromethoxyphenyl-hydrazone-sensitive fluorescence quenching of quinacrine dihydrochloride. The data indicate that reduction of DMSO by E. coli is catalyzed by an anaerobic electron transport chain, resulting in the formation of a proton motive force.

  16. Ultrastructural observation of altered chloroplast morphology in space-grown Brassica rapa cotyledons.

    PubMed

    Jiao, S; Hilaire, E; Paulsen, A Q; Guikema, J A

    1999-07-01

    Photosynthesis will be indispensable in a bioregenerative life-support systems for long space missions. It is critical understand the effects of space on this complex process, especially the loss of gravity. Past has noted changes in plant growth and development; differences about cell size, shape, division, and differentiation; and plastid distribution and structure alterations. The amyloplast-containing columelar cells in root tips were carefully examined since they are likely gravity-sensing sites. Changes on photosynthetic physiology and chloroplast structure have been reported. Both increases and decreases of chlorophyll and carotenoid contents were reported. Structural changes of thylakoid membranes in chloroplasts were observed in pea and Arabidopsis grown in space or clinorotation. Recently, a decrease of CO2 assimilation rate and of electron transport rate of both PSI and PSII on thylakoid membranes were reported in space-grown wheat. These imply an overall decrease of photosynthetic activities, and implicate thylakoid-old structural changes. For example, PSI activity, and its reaction center subunits (PsaA, PsaB, and PsaC) and the LHCIs, were decreased under microgravity. Here, we further examined cellular morphology and ultrastructural features of the chloroplast and its thylakoid membranes by electron microscopy and in situ immunolocalization. PMID:11543043

  17. Quantitative analysis of live cells using digital holographic microscopy

    NASA Astrophysics Data System (ADS)

    Lewis, Tan Rongwei; Qu, Weijuan; Chee, Oi Choo; Singh, Vijay Raj; Asundi, Anand

    2009-12-01

    During the life time of a cell, it goes through changes to the plasma membrane as well as its internal structures especially distinctive during processes like cell division and death. Different types of microscope are used to fulfill the observation of the cell's variation. In our experiment, Vero cells have been investigated by using phase contrast microscopy and digital holographic microscopy (DHM). A comparison of the images obtained for cell division is presented here. The conventional phase contrast microscope provided a good imaging method in the real time analysis of cell division. The off-axis digital hologram recorded by the DHM system can be reconstructed to obtain both the intensity image and phase contrast image of the test object. These can be used for live cell imaging to provide multiple results from a single equipment setup. The DHM system, besides being a qualitative tool, is able to provide quantitative results and 3D images of the cell division process. The ability of DHM to provide quantitative analysis makes it an ideal tool for life science applications.

  18. Quantitative analysis of live cells using digital holographic microscopy

    NASA Astrophysics Data System (ADS)

    Lewis, Tan Rongwei; Qu, Weijuan; Chee, Oi Choo; Singh, Vijay Raj; Asundi, Anand

    2010-03-01

    During the life time of a cell, it goes through changes to the plasma membrane as well as its internal structures especially distinctive during processes like cell division and death. Different types of microscope are used to fulfill the observation of the cell's variation. In our experiment, Vero cells have been investigated by using phase contrast microscopy and digital holographic microscopy (DHM). A comparison of the images obtained for cell division is presented here. The conventional phase contrast microscope provided a good imaging method in the real time analysis of cell division. The off-axis digital hologram recorded by the DHM system can be reconstructed to obtain both the intensity image and phase contrast image of the test object. These can be used for live cell imaging to provide multiple results from a single equipment setup. The DHM system, besides being a qualitative tool, is able to provide quantitative results and 3D images of the cell division process. The ability of DHM to provide quantitative analysis makes it an ideal tool for life science applications.

  19. Epitaxial strontium titanate films grown by atomic layer deposition on SrTiO{sub 3}-buffered Si(001) substrates

    SciTech Connect

    McDaniel, Martin D.; Posadas, Agham; Ngo, Thong Q.; Dhamdhere, Ajit; Smith, David J.; Demkov, Alexander A.; Ekerdt, John G. [Department of Chemical Engineering, University of Texas at Austin, 1 University Station C0400, Austin, Texas 78712 (United States); Department of Physics, University of Texas at Austin, 1 University Station C1600, Austin, Texas 78712 (United States); Department of Chemical Engineering, University of Texas at Austin, 1 University Station C0400, Austin, Texas 78712 (United States); Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States); Department of Physics, University of Texas at Austin, 1 University Station C1600, Austin, Texas 78712 (United States); Department of Chemical Engineering, University of Texas at Austin, 1 University Station C0400, Austin, Texas 78712 (United States)

    2013-01-15

    Epitaxial strontium titanate (STO) films have been grown by atomic layer deposition (ALD) on Si(001) substrates with a thin STO buffer layer grown by molecular beam epitaxy (MBE). Four unit cells of STO grown by MBE serve as the surface template for ALD growth. The STO films grown by ALD are crystalline as-deposited with minimal, if any, amorphous SiO{sub x} layer at the STO-Si interface. The growth of STO was achieved using bis(triisopropylcyclopentadienyl)-strontium, titanium tetraisopropoxide, and water as the coreactants at a substrate temperature of 250 Degree-Sign C. In situ x-ray photoelectron spectroscopy (XPS) analysis revealed that the ALD process did not induce additional Si-O bonding at the STO-Si interface. Postdeposition XPS analysis also revealed sporadic carbon incorporation in the as-deposited films. However, annealing at a temperature of 250 Degree-Sign C for 30 min in moderate to high vacuum (10{sup -6}-10{sup -9} Torr) removed the carbon species. Higher annealing temperatures (>275 Degree-Sign C) gave rise to a small increase in Si-O bonding, as indicated by XPS, but no reduced Ti species were observed. X-ray diffraction revealed that the as-deposited STO films were c-axis oriented and fully crystalline. A rocking curve around the STO(002) reflection gave a full width at half maximum of 0.30 Degree-Sign {+-} 0.06 Degree-Sign for film thicknesses ranging from 5 to 25 nm. Cross-sectional transmission electron microscopy revealed that the STO films were continuous with conformal growth to the substrate and smooth interfaces between the ALD- and MBE-grown STO. Overall, the results indicate that thick, crystalline STO can be grown on Si(001) substrates by ALD with minimal formation of an amorphous SiO{sub x} layer using a four-unit-cell STO buffer layer grown by MBE to serve as the surface template.

  20. SERS-applicable silver nanoisland film grown under protective coating

    NASA Astrophysics Data System (ADS)

    Reduto, I.; Chervinskii, S.; Matikainen, A.; Baklanov, A.; Kamenskii, A.; Lipovskii, A.

    2014-10-01

    We have used recently developed out-diffusion technique of growing silver nanoisland films on glass surface to grow silver nanoislands under TiO2 layer deposited on the glass. After covering the surface of silver ion-exchanged glasses with TiO2 film using atomic layer deposition technique and subsequent thermal processing of the samples in hydrogen their optical absorption spectra demonstrate the absorption peak corresponding to surface plasmon resonance in grown silver nanoislands. The spectral position of the peak is shifted relatively to the peak observed in the spectra of the nanoisland film grown on the surface of ion exchanged and annealed glass samples without dielectric cover. The applicability of the silver nanoislands grown under several nm thick protective TiO2 coating in surface-enhanced Raman scattering spectroscopy is demonstrated.

  1. Entrapment of Bacteria in Fluid Inclusions in Laboratory-Grown Halite

    NASA Astrophysics Data System (ADS)

    Adamski, James C.; Roberts, Jennifer A.; Goldstein, Robert H.

    2006-08-01

    Cells of the bacterium Pseudomonas aeruginosa, which were genetically modified to produce green fluorescent protein, were entrapped in fluid inclusions in laboratory-grown halite. The bacteria were used to inoculate NaCl-saturated aqueous solutions, which were allowed to evaporate and precipitate halite. The number, size, and distribution of fluid inclusions were highly variable, but did not appear to be affected by the presence of the bacteria. Many of the inclusions in crystals from inoculated solutions contained cells in populations ranging from two to 20. Microbial attachment to crystal surfaces was neither evident nor necessary for entrapment. Cells occurred exclusively within fluid inclusions and were not present in the crystal matrix. In both the inclusions and the hypersaline solution, the cells fluoresced and twitched, which indicates that the bacteria might have remained viable after entrapment. The fluorescence continued up to 13 months after entrapment, which indicates that little degradation of the bacteria occurred over that time interval. The entrapment, fluorescence, and preservation of cells were independent of the volume of hypersaline solution used or whether the solutions were completely evaporated prior to crystal extraction. The results of this study have a wide range of implications for the long-term survival of microorganisms in fluid inclusions and their detection through petrography. The results also demonstrate the preservation potential for microbes in hypersaline fluid inclusions, which could allow cells to survive harsh conditions of space, the deep geologic past, or burial in sedimentary basins.

  2. Entrapment of bacteria in fluid inclusions in laboratory-grown halite.

    PubMed

    Adamski, James C; Roberts, Jennifer A; Goldstein, Robert H

    2006-08-01

    Cells of the bacterium Pseudomonas aeruginosa, which were genetically modified to produce green fluorescent protein, were entrapped in fluid inclusions in laboratory-grown halite. The bacteria were used to inoculate NaCl-saturated aqueous solutions, which were allowed to evaporate and precipitate halite. The number, size, and distribution of fluid inclusions were highly variable, but did not appear to be affected by the presence of the bacteria. Many of the inclusions in crystals from inoculated solutions contained cells in populations ranging from two to 20. Microbial attachment to crystal surfaces was neither evident nor necessary for entrapment. Cells occurred exclusively within fluid inclusions and were not present in the crystal matrix. In both the inclusions and the hypersaline solution, the cells fluoresced and twitched, which indicates that the bacteria might have remained viable after entrapment. The fluorescence continued up to 13 months after entrapment, which indicates that little degradation of the bacteria occurred over that time interval. The entrapment, fluorescence, and preservation of cells were independent of the volume of hypersaline solution used or whether the solutions were completely evaporated prior to crystal extraction. The results of this study have a wide range of implications for the long-term survival of microorganisms in fluid inclusions and their detection through petrography. The results also demonstrate the preservation potential for microbes in hypersaline fluid inclusions, which could allow cells to survive harsh conditions of space, the deep geologic past, or burial in sedimentary basins. PMID:16916282

  3. Shock initiation experiments on ratchet grown PBX 9502

    SciTech Connect

    Gustavsen, Richard L [Los Alamos National Laboratory; Thompson, Darla G [Los Alamos National Laboratory; Olinger, Barton W [Los Alamos National Laboratory; Deluca, Racci [Los Alamos National Laboratory; Bartram, Brian D [Los Alamos National Laboratory; Pierce, Timothy H [Los Alamos National Laboratory; Sanchez, Nathaniel J [Los Alamos National Laboratory

    2010-01-01

    This study compares the shock initiation behavior of PBX 9502 pressed to less than nominal density (nominal density is 1.890 {+-} 0.005 g/cm{sup 3}) with PBX 9502 pressed to nominal density and then ''ratchet grown'' to low density. PBX 9502 is an insensitive plastic bonded explosive consisting of 95 weight % dry-aminated tri-amino-tri-nitro-benzene (TATB) and 5 weight % Kel-F 800 plastic binder. ''Ratchet growth'' - an irreversible increase in specific volume - occurs when an explosive based on TATB is temperature cycled. The design of our study is as follows: PBX 9502, all from the same lot, received the following four treatments. Samples in the first group were pressed to less than nominal density. These were not ratchet grown and used as a baseline. Samples in the second group were pressed to nominal density and then ratchet grown by temperature cycling 30 times between -54 C and +80 C. Samples in the final group were pressed to nominal density and cut into 100 mm by 25.4 mm diameter cylinders. During thermal cycling the cylinders were axially constrained by a 100 psi load. Samples for shock initiation experiments were cut perpendicular (disks) and parallel (slabs) to the axial load. The four sample groups can be summarized with the terms pressed low, ratchet grown/no load, axial load/disks, and axial load/slabs. All samples were shock initiated with nearly identical inputs in plate impact experiments carried out on a gas gun. Wave profiles were measured after propagation through 3, 4, 5, and 6 mm of explosive. Side by side comparison of wave profiles from different samples is used as a measure of relative sensitivity. All reduced density samples were more shock sensitive than nominal density PBX 9502. Differences in shock sensitivity between ratchet grown and pressed to low density PBX 9502 were small, but the low density pressings are slightly more sensitive than the ratchet grown samples.

  4. Anatomical features of pepper plants (Capsicum annuum L.) grown under red light-emitting diodes supplemented with blue or far-red light

    NASA Technical Reports Server (NTRS)

    Schuerger, A. C.; Brown, C. S.; Stryjewski, E. C.

    1997-01-01

    Pepper plants (Capsicum annuum L. cv., Hungarian Wax) were grown under metal halide (MH) lamps or light-emitting diode (LED) arrays with different spectra to determine the effects of light quality on plant anatomy of leaves and stems. One LED (660) array supplied 90% red light at 660 nm (25nm band-width at half-peak height) and 1% far-red light between 700-800nm. A second LED (660/735) array supplied 83% red light at 660nm and 17% far-red light at 735nm (25nm band-width at half-peak height). A third LED (660/blue) array supplied 98% red light at 660nm, 1% blue light between 350-550nm, and 1% far-red light between 700-800nm. Control plants were grown under broad spectrum metal halide lamps. Plants were gron at a mean photon flux (300-800nm) of 330 micromol m-2 s-1 under a 12 h day-night photoperiod. Significant anatomical changes in stem and leaf morphologies were observed in plants grown under the LED arrays compared to plants grown under the broad-spectrum MH lamp. Cross-sectional areas of pepper stems, thickness of secondary xylem, numbers of intraxylary phloem bundles in the periphery of stem pith tissues, leaf thickness, numbers of choloplasts per palisade mesophyll cell, and thickness of palisade and spongy mesophyll tissues were greatest in peppers grown under MH lamps, intermediate in plants grown under the 660/blue LED array, and lowest in peppers grown under the 660 or 660/735 LED arrays. Most anatomical features of pepper stems and leaves were similar among plants grown under 660 or 660/735 LED arrays. The effects of spectral quality on anatomical changes in stem and leaf tissues of peppers generally correlate to the amount of blue light present in the primary light source.

  5. Solution Grown Antimony Doped Zinc Oxide Films

    NASA Astrophysics Data System (ADS)

    Riley, Conor T.

    Zinc oxide is an extensively studied semiconducting material due to its versatile properties applicable to many technologies such as electronics, optoelectronics, sensing and renewable energy. Although zinc oxide films have been created for device fabrication, the methods used to synthesize them are expensive and unrealistic for affordable commercial devices. In addition, zinc oxide is intrinsically n-type making the realization of stable p-type materials a great challenge for light emitting diodes, solar cells and UV lasing. In this thesis zinc oxide films are created using low cost solution methods. To accomplish this, a previously unreported surfactant, tert-butanol, is used. Several controlled experiments vary the concentration of tert-butanol, zinc and oxygen sources to demonstrate the ability of tert-butanol to create low cost films. Further, small amounts of antimony glycolate are added to the reaction solution, to create antimony doped zinc oxide films on sapphire and silicon substrates. Although hall measurements indicate that the films are n-type, a discussion of antimony activation provides a feasible path for the realization of low cost, p-type zinc oxide films.

  6. GaNAsP: An intermediate band semiconductor grown by gas-source molecular beam epitaxy

    SciTech Connect

    Kuang, Y. J. [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States)] [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States); Yu, K. M.; Walukiewicz, W. [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Kudrawiec, R. [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States) [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Institute of Physics, Wroclaw University of Technology, Wybrzeze, Wyspianskiego 27, 50-370 Wroclaw (Poland); Luce, A. V. [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States) [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Ting, M. [Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States)] [Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States); Tu, C. W. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)] [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

    2013-03-18

    Dilute nitride GaNAsP thin films were grown via a GaAsP metamorphic buffer on GaP(100) substrate with gas-source molecular beam epitaxy. The compositions of this III-V-V-V compound were determined by channeling Rutherford backscattering spectroscopy and nuclear reaction analysis. Photoreflectance shows two distinctive transitions from the valence band to the split conduction bands due to N incorporation. Photoluminescence and optical absorption show the fundamental bandgap of Ga(N)AsP is largely tailored by the small amount of N. The observed multiband characteristics and the bandgap tunability of GaNAsP are two merits that fit into the intermediate-band solar cell roadmap, and GaNAsP of high crystal quality provides a strong candidate for intermediate band solar cell materials.

  7. Evaluation of cells and biological reagents for adventitious agents using degenerate primer PCR and massively parallel sequencing.

    PubMed

    McClenahan, Shasta D; Uhlenhaut, Christine; Krause, Philip R

    2014-12-12

    We employed a massively parallel sequencing (MPS)-based approach to test reagents and model cell substrates including Chinese hamster ovary (CHO), Madin-Darby canine kidney (MDCK), African green monkey kidney (Vero), and High Five insect cell lines for adventitious agents. RNA and DNA were extracted either directly from the samples or from viral capsid-enriched preparations, and then subjected to MPS-based non-specific virus detection with degenerate oligonucleotide primer (DOP) PCR. MPS by 454, Illumina MiSeq, and Illumina HiSeq was compared on independent samples. Virus detection using these methods was reproducibly achieved. Unclassified sequences from CHO cells represented cellular sequences not yet submitted to the databases typically used for sequence identification. The sensitivity of MPS-based virus detection was consistent with theoretically expected limits based on dilution of virus in cellular nucleic acids. Capsid preparation increased the number of viral sequences detected. Potential viral sequences were detected in several samples; in each case, these sequences were either artifactual or (based on additional studies) shown not to be associated with replication-competent viruses. Virus-like sequences were more likely to be identified in BLAST searches using virus-specific databases that did not contain cellular sequences. Detected viral sequences included previously described retrovirus and retrovirus-like sequences in CHO, Vero, MDCK and High Five cells, and nodavirus and endogenous bracovirus sequences in High Five insect cells. Bovine viral diarrhea virus, bovine hokovirus, and porcine circovirus sequences were detected in some reagents. A recently described parvo-like virus present in some nucleic acid extraction resins was also identified in cells and extraction controls from some samples. The present study helps to illustrate the potential for MPS-based strategies in evaluating the presence of viral nucleic acids in various sample types, including cell culture substrates and vaccines. PMID:25454874

  8. Nanoscale Ice: Spectroscopic Ellipsometry of Epitaxially-Grown Crystals

    NASA Astrophysics Data System (ADS)

    Cumiskey, A.; Grippaldi, J.; Magee, N. B.

    2011-12-01

    A new laboratory technique has been developed to examine the surface characteristics and kinetics of ice crystals at the nanoscale. Uncertainties remain regarding the fundamental physics of nucleation and depositional growth in atmospheric ice crystals. These molecular-scale uncertainties propagate upward into modeling outcomes at all scales of atmospheric interest: particle models, cloud models, mesoscale models, and climate models. Molecular-scale growth mechanisms and kinetics have been mainly inferred from bulk and particle-scale experiments as well as crystal-growth theory. The precarious nature of the ice surface resisted the first generation of direct nanoscale probing technologies, but new in-situ techniques including ESEM, AFM, and ellipsometry promise to divulge a wealth of new knowledge. Spectroscopic ellipsometry measures changes in the polarization state of light as it reflects off the surface of a thin film. This non-destructive technique is capable of measuring layer thicknesses as small as a single monolayer (~1 Å) and up to thicknesses of ~10 ?m. Other physical parameters including index of refraction and surface roughness are also accessible. At the TCNJ Cloud Physics Laboratory, a Horiba Scientific Auto-SE ellipsometer (440 - 1000 nm spectral range) has been adapted for in-situ measurements of ice crystals. The ice crystals are grown epitaxially on various horizontal substrates in a custom-built static diffusion chamber. The diffusion chamber is housed within a vacuum chamber and an optical path is provided from the ellipsometer light source to sample stage and back to the ellipsometer analyzer at 75° from normal. The diffusion chamber is cooled in two stages, with initial cooling accomplished with a fluid-chilled block and final chilling controlled by two independent thermoelectric cells. A wide range of temperatures, pressures, and saturation ratios are accessible: from 0°C to -30°C, 50mb to atmospheric pressure, and from subsaturated to greater that 200% RHi. Temperature and moisture profiles are continuously determined by platinum resistance thermometers. Optimization of cooling efficiencies are under way and should permit extension of temperature range to -60°C. Ongoing efforts are targeted at kinetic measurements of thickness changes in order to identify growth thresholds as a function of ambient conditions and nucleation mechanism.

  9. Formation of Odontoblast-Like Cells from Cultured Human Dental Pulp Cells on Dentin In Vitro

    Microsoft Academic Search

    George T.-J. Huang; Kristina Shagramanova; Selina W. Chan

    2006-01-01

    Recent characterization of human dental pulp stem cells has shed new light on the understanding of the odontoblastic lineage. The purpose of the study was to characterize human adult dental pulp cells isolated and cultured in vitro and to examine the cell differentiation potential grown on dentin. We observed that some pulp cells isolated with an enzyme-digestion approach proliferated at

  10. Interactions of Prostate Cancer Cells to Human Microvascular Endothelial Cells Under Shear Stress Conditions

    Microsoft Academic Search

    Hao Xu; N. Kalu; P. Raghavan; M. H. Kim; Kytai Truong Nguyen

    2007-01-01

    The interactions between prostate cancer cells with endothelial cells in the microvessels play an important role in prostate tumor metastasis. However, not many studies have been conducted to investigate the adhesion of prostate cancer cells on vascular endothelium and related mechanisms and modulators. In this study, human microvascular endothelial cells (HMEC) grown on glass slides were exposed to two different

  11. Ultrastructural study of long-term canine distemper virus infection in tissue culture cells.

    PubMed Central

    Narang, H K

    1982-01-01

    The morphogenesis of canine distemper virus was studied in Vero cell cultures for 43 days post-inoculation. Active replication of the virus was observed by electron microscopy and assay from 12 h after inoculation on, and peak production was observed on days 5, 14, and 22. From day 28 on, constant but smaller amounts of infectious virus were detected. Two ultrastructural types of intracytoplasmic nucleoprotein filaments were observed; although they first appeared at different times, their subsequent chronological patterns of development were similar. The cells apparently became free of virus by a mechanism of vacuolation. Intranuclear filaments were seen about day 11 and appeared to increase in number thereafter, whereas the infectious titer declined. Possible mechanisms of persistence are discussed in the light of these findings. Images PMID:7076301

  12. African swine fever virus infects macrophages, the natural host cells, via clathrin- and cholesterol-dependent endocytosis.

    PubMed

    Galindo, Inmaculada; Cuesta-Geijo, Miguel Angel; Hlavova, Karolina; Muñoz-Moreno, Raquel; Barrado-Gil, Lucía; Dominguez, Javier; Alonso, Covadonga

    2015-03-16

    The main cellular target for African swine fever virus (ASFV) is the porcine macrophage. However, existing data about the early phases of infection were previously characterized in non-leukocyte cells such as Vero cells. Here, we report that ASFV enters the natural host cell using dynamin-dependent and clathrin-mediated endocytosis. This pathway is strongly pH-dependent during the first steps of infection in porcine macrophages. We investigated the effect of drugs inhibiting several endocytic pathways in macrophages and compared ASFV with vaccinia virus (VV), which apparently involves different entry pathways. The presence of cholesterol in cellular membranes was found to be essential for a productive ASFV infection while actin-dependent endocytosis and the participation of phosphoinositide-3-kinase (PI3K) activity were other cellular factors required in the process of viral entry. These findings improved our understanding of the ASFV interactions with macrophages that allow for successful viral replication. PMID:25662020

  13. Characterization of cell lines stably transfected with rubella virus replicons

    SciTech Connect

    Tzeng, Wen-Pin; Xu, Jie [Department of Biology, Georgia State University, P.O. Box 4010, Atlanta GA 30302-4010 (United States)] [Department of Biology, Georgia State University, P.O. Box 4010, Atlanta GA 30302-4010 (United States); Frey, Teryl K., E-mail: tfrey@gsu.edu [Department of Biology, Georgia State University, P.O. Box 4010, Atlanta GA 30302-4010 (United States)

    2012-07-20

    Rubella virus (RUBV) replicons expressing a drug resistance gene and a gene of interest were used to select cell lines uniformly harboring the replicon. Replicons expressing GFP and a virus capsid protein GFP fusion (C-GFP) were compared. Vero or BHK cells transfected with either replicon survived drug selection and grew into a monolayer. However, survival was {approx}9-fold greater following transfection with the C-GFP-replicon than with the GFP-expressing replicon and while the C-GFP-replicon cells grew similarly to non-transfected cells, the GFP-replicon cells grew slower. Neither was due to the ability of the CP to enhance RNA synthesis but survival during drug selection was correlated with the ability of CP to inhibit apoptosis. Additionally, C-GFP-replicon cells were not cured of the replicon in the absence of drug selection. Interferon-alpha suppressed replicon RNA and protein synthesis, but did not cure the cells, explaining in part the ability of RUBV to establish persistent infections.

  14. Gravity, chromosomes, and organized development in aseptically cultured plant cells

    NASA Technical Reports Server (NTRS)

    Krikorian, Abraham D.

    1993-01-01

    The objectives of the PCR experiment are: to test the hypothesis that microgravity will in fact affect the pattern and developmental progression of embryogenically competent plant cells from one well-defined, critical stage to another; to determine the effects of microgravity in growth and differentiation of embryogenic carrot cells grown in cell culture; to determine whether microgravity or the space environment fosters an instability of the differentiated state; and to determine whether mitosis and chromosome behavior are adversely affected by microgravity. The methods employed will consist of the following: special embryogenically competent carrot cell cultures will be grown in cell culture chambers provided by NASDA; four cell culture chambers will be used to grow cells in liquid medium; two dishes (plant cell culture dishes) will be used to grow cells on a semi-solid agar support; progression to later embryonic stages will be induced in space via crew intervention and by media manipulation in the case of liquid grown cell cultures; progression to later stages in case of semi-solid cultures will not need crew intervention; embryo stages will be fixed at a specific interval (day 6) in flight only in the case of liquid-grown cultures; and some living cells and somatic embryos will be returned for continued post-flight development and 'grown-out.' These will derive from the semi-solid grown cultures.

  15. Generation of dendritic cell-based vaccines for cancer therapy

    Microsoft Academic Search

    G Reinhard; A Märten; S M Kiske; F Feil; T Bieber; I G H Schmidt-Wolf; IGH Schmidt-Wolf

    2002-01-01

    Dendritic cells play a major role in the generation of immunity against tumour cells. They can be grown under various culture conditions, which influence the phenotypical and functional properties of dendritic cells and thereby the consecutive immune response mainly executed by T cells. Here we discuss various conditions, which are important during generation and administration of dendritic cells to elicit

  16. Ancient maize from Chacoan great houses: Where was it grown?

    Microsoft Academic Search

    Larry Benson; Linda Cordell; Kirk Vincent; Howard Taylor; John Stein; G. Lang Farmer; Kiyoto Futa

    2003-01-01

    In this article, we compare chemical (87Sr\\/86Sr and elemental) analyses of archaeological maize from dated contexts within Pueblo Bonito, Chaco Canyon, New Mexico, to potential agricultural sites on the periphery of the San Juan Basin. The oldest maize analyzed from Pueblo Bonito probably was grown in an area located 80 km to the west at the base of the Chuska

  17. SPECTRAL REFLECTANCE OF ALFALFA GROWN UNDER DIFFERENT WATER TABLE DEPTHS

    Microsoft Academic Search

    Y. Y. Aldakheel; A. H. Assaedi; M. A. Al-Abdussalam

    The main objective of this study is to determine the growth response and water use effeciency of alfalfa (Medicago sativa L.) grown in the field under four water table levels and two rates of water supply under the climatic condition of Al-Hassa oasis in Saudi Ara- bia. The potential use and management of water table depth, to function as sub-irrigation

  18. PRODUCTION AND NUTRIENT REMOVAL BY PERIPHYTON GROWN IN DAIRY MANURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Growing algae to scrub nutrients from manure presents an alternative to the current practice of land application and provides utilizable algal biomass as an end product. Previous studies in our laboratory on manure from two different dairy farms showed that removal by periphyton grown on ATS (algal...

  19. Original article Foliar senescence in maize plants grown

    E-print Network

    Paris-Sud XI, Université de

    Original article Foliar senescence in maize plants grown under different water regimes Arturo) Abstract - The leaf ontogeny of potted maize plants subjected to severe water stress was carried out and water-stressed plants received 100 and 50 % of the water evapotranspired, respectively. After 30 days

  20. Yield performance of cowpea plant introductions grown in calcareous soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cowpea or Southernpea [Vigna unguiculata (L.) Walp.] is an important legume crop used as a feed for livestock, as a green vegetable and for consumption of its dry beans which provide 22-25% protein. The crop is very sensitive to alkaline soil conditions. When grown at a soil pH of 7.5 or higher, co...