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Various Strains (various + strain)
Selected AbstractsVisualization of Surface-specific Antigens in Various Strains of Enterotoxigenic E. coliANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005S. Lüdi Proteinaceous surface antigens of enterotoxigenic E. coli (ETEC) appear as pili, and are important virulence factors as they allow bacteria to attach to the small intestinal mucosa. Surface antigens are classified as colonization factor antigens (CFA) and coli surface antigens (CS). Known groups include CFA/I, CFA/II (consisting of CS1, CS2 and CS3), CA/III and CFA/IV (consisting of CS4, CS5 and CS6). The goal of the present study was to examine the morphology of pili by transmission electron microscopy (TEM) and to localize specific surface antigens by immunolabelling. Using different strains of E. coli grown under various culture conditions, pili were visualized by negative staining and corresponding surface antigens were demonstrated by immunogold-labelling using both polyclonal and monoclonal antibodies. Expression of pili was dependent on culture conditions and sample handling. In contrast to CFA/I and CS3, CS6 pili were not detectable after negative staining. Selected antibodies, however, allowed surface antigens to be demonstrated unequivocally. These results will be of value in investigating the expression of colonizing factors in genetically modified bacterial strains. [source] Search of Microorganisms that Degrade PAHs under Alkaline ConditionsENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 4 2004A. Gerbeth Abstract Bacterial strains were enriched from building rubble contaminated with polycyclic aromatic hydrocarbons (PAHs). These strains were studied as an inoculum in bioremediation processes with contaminated building rubble. The selection criteria for the bacteria were broad profiles in PAH degradation, stable expression of the traits and tolerance to alkaline conditions. Various strains of Micrococcus sp., Dietzia sp., Rhodococcus sp. and Pseudomonas sp. met the selection criteria. In general, degradative activity was limited at higher pH values. Strains of Micrococcus were suitable for practical use as complete degradation of various PAHs was observed at pH values exceeding 10. Strains of Dietzia sp. showed broad PAH degradation profile, but in some cases degradation came to a halt leaving some of the PAHs unutilized. With Dietzia sp. this could be due to inhibitory effects from the accumulation of toxic PAH metabolic products and/or growth-limiting media conditions. [source] Thermomyces lanuginosus: properties of strains and their hemicellulasesFEMS MICROBIOLOGY REVIEWS, Issue 1 2003Suren Singh Abstract The non-cellulolytic Thermomyces lanuginosus is a widespread and frequently isolated thermophilic fungus. Several strains of this fungus have been reported to produce high levels of cellulase-free ,-xylanase both in shake-flask and bioreactor cultivations but intraspecies variability in terms of ,-xylanase production is apparent. Furthermore all strains produce low extracellular levels of other hemicellulases involved in hemicellulose hydrolysis. Crude and purified hemicellulases from this fungus are stable at high temperatures in the range of 50,80°C and over a broad pH range (3,12). Various strains are reported to produce a single xylanase with molecular masses varying between 23 and 29 kDa and pI values between 3.7 and 4.1. The gene encoding the T. lanuginosus xylanase has been cloned and sequenced and is shown to be a member of family 11 glycosyl hydrolases. The crystal structure of the xylanase indicates that the enzyme consists of two ,-sheets and one ,-helix and forms a rigid complex with the three central sugars of xyloheptaose whereas the peripheral sugars might assume different configurations thereby allowing branched xylan chains to be accepted. The presence of an extra disulfide bridge between the ,-strand and the ,-helix, as well as to an increase in the density of charged residues throughout the xylanase might contribute to the thermostability. The ability of T. lanuginosus to produce high levels of cellulase-free thermostable xylanase has made the fungus an attractive source of thermostable xylanase with potential as a bleach-boosting agent in the pulp and paper industry and as an additive in the baking industry. [source] Cellular and molecular mechanisms of bleomycin-induced murine scleroderma: current update and future perspectiveEXPERIMENTAL DERMATOLOGY, Issue 2 2005Toshiyuki Yamamoto Abstract:, Scleroderma is a fibrotic condition characterized by immunologic abnormalities, vascular injury and increased accumulation of matrix proteins in the skin. Although the aetiology of scleroderma is not fully elucidated, a growing body of evidence suggests that extracellular matrix overproduction by activated fibroblasts results from complex interactions among endothelial cells, lymphocytes, macrophages and fibroblasts, via a number of mediators. Cytokines, chemokines and growth factors secreted by inflammatory cells and mesenchymal cells (fibroblasts and myofibroblasts) play an important role in the fibrotic process of scleroderma. Recently, we established a murine model of scleroderma by repeated local injections of bleomycin. Dermal sclerosis was induced in various mouse strains, although the intensity of dermal sclerosis varied among various strains. Histopathological and biochemical analysis demonstrated that this experimental murine scleroderma reflected a number of aspects of human scleroderma. Further investigation of the cellular and molecular mechanisms of inflammatory reaction, fibroblast activation and extracellular matrix deposition following dermal injury by bleomycin treatment will lead to the better understanding of the pathophysiology and the exploration of effective treatment against scleroderma. This review summarizes recent progress of the cellular and molecular events in the pathogenesis of bleomycin-induced scleroderma; moreover, further perspective by using this mouse model has been discussed. [source] Risk and control of waterborne cryptosporidiosisFEMS MICROBIOLOGY REVIEWS, Issue 2 2002Joan B. Rose Abstract Cryptosporidium remains at the forefront of studies on waterborne disease transmission and abatement. The impact of environmental land use patterns which contribute animal and human waste, climatic precipitation leading to a strong association with outbreaks, and community infrastructure and water treatment are now recognized as contributing factors in the potential for waterborne spread of the protozoan. Advances in detection methodologies, including the ability to genotype various strains of this organism, have shown that human wastes are often the source of the contamination and cell culture techniques have allowed insight into the viability of the oocyst populations. Currently water treatment has focused on UV and ozone disinfection as most promising for the inactivation of this protozoan pathogen. [source] Evidence for a cost of immunity when the crustacean Daphnia magna is exposed to the bacterial pathogen Pasteuria ramosaJOURNAL OF ANIMAL ECOLOGY, Issue 6 2007TOM J. LITTLE Summary 1The deployment of the immune system has the obvious potential to ameliorate infection outcomes, but immune responses can also harm hosts by either damaging host tissues or monopolizing resources, leading to enhanced mortality. To gain insight into such a ,cost of immunity' when the crustacean Daphnia magna is challenged with the bacterium Pasteuria ramosa, we measured survivorship among hosts that resisted infection following exposure to various strains and doses of the parasite. 2In the first of two experiments, these exposures were: single exposures with relatively non-aggressive strains, double exposures with non-aggressive strains, and exposure to aggressive strains. Mortality increased across this gradient of exposure. In a second experiment, we varied the dose of the most aggressive P. ramosa strain and found that resisting infection when a large dose was applied resulted in greater mortality than when a medium or low dose was applied. 3Assuming that resistance is accomplished with an immune response, and that more aggressive parasites and/or larger doses of parasites are more immunostimulatory, these data are compatible with a cost of immunity. Indeed, in terms of survival, resisting parasites can be more harmful than infection. [source] Ralstonia pickettii in environmental biotechnology: potential and applicationsJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2007M.P. Ryan Summary Xenobiotic pollutants such as toluene and trichloroethylene are released into the environment by various industrial processes. Ralstonia pickettii possess significant biotechnological potential in the field of bioremediation and has demonstrated the ability to breakdown many of these toxic substances. Here, we provide a description of the major compounds that various strains of R. pickettii are capable of degrading and a brief review of their breakdown pathways and an argument for its use in bioremediation. [source] Effects of hydrogen peroxide on light emission by various strains of marine luminescent bacteriaJOURNAL OF BASIC MICROBIOLOGY, Issue 3 2004Andrey M. Katsev Light-emitting bacteria are the most abundant and widespread luminescent organisms. Most species of such bacteria live in marine environments. However, until recently, biological role of bacterial luminescence remained unknown. Recent studies indicated that light produced in bacterial cells may stimulate DNA repair. Therefore, it is not surprising that agents that cause DNA damage induce expression of lux genes. Moreover, it was proposed previously that bacterial luciferases may be involved in detoxification of reactive oxygen species. Recently, this hypothesis was confirmed experimentally. Here we investigated effects of hydrogen peroxide on light emission by various strains of luminescent bacteria. We found that luminescence of strains with luciferase of fast kinetics of reaction decreased at considerably lower concentrations of H2O2 than that of strains with luciferase of the slow kinetics. The action (either direct or indirect) of luciferases as anti-oxidants seemed to be independent of activity of catalase, which was found to be different in various strains. Therefore, it seems that luciferases of the slow kinetics are more efficient in detoxification of reactive oxygen species than those of the fast kinetics. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Metabolism of fungicidal cyanooximes, cymoxanil and analogues in various strains of Botrytis cinereaPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 2 2009Frédérique Tellier Abstract BACKGROUND: The metabolism of cymoxanil [1-(2-cyano-2-methoxyiminoacetyl)-3-ethylurea] and fungicidal cyanooxime analogues was monitored on three phenotypes of Botrytis cinerea Pers. ex Fr. differing in their sensitivity towards cymoxanil. For this purpose, labelled [2- 14C]cymoxanil was added either to the culture medium of these strains or to its cell-free extract. RESULTS: In the culture medium of the most sensitive strain, four main metabolites were detected. Three were isolated and identified. Cymoxanil was quickly metabolised by at least three concurrent enzymatic pathways: (i) cyclisation leading, after hydrolysis, to ethylparabanic acid, (ii) reduction giving demethoxylated cymoxanil, (iii) hydrolysis followed by reduction and then acetylation leading to N -acetylcyanoglycine. In the cell-free extract of the same strain, only the first and the second of these enzymatic reactions occurred. By comparing the metabolic profile of the most sensitive strain with that of the less sensitive ones, it was shown that the decrease in sensitivity to cymoxanil correlates with a reduced acetylcyanoglycine formation. Among all metabolites, only N -acetylcyanoglycine is active against the most sensitive strain. Moreover, in a culture of this strain, two other fungicidal cyanooximes were also metabolised into this metabolite. CONCLUSION: The formation of N -acetylcyanoglycine may play an important role in the fungitoxicity of cymoxanil and cyanooxime derivatives. Copyright © 2008 Society of Chemical Industry [source] Placental macrophage contact induces complete replicative cycle of human immunodeficiency virus in latently infected syncytiotrophoblast cells: role of interleukine-6 and tumor necrosis factor-,AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 3 2002Ferenc D. Tóth The phenotypic mixing between human immunodeficiency virus type 1 (HIV-1) and vesicular stomatitis virus (VSV) has been exploited to assay the susceptibility of human term syncytiotrophoblast cells to penetration by various strains of HIV-1. VSV (HIV-1IIIB) and VSV (HIV-1Ba-L) pseudotypes were found to enter syncytiotrophoblasts. Infection of syncytiotrophoblasts was mediated by envelope glycoproteins of IIIB and Ba-L strains of HIV-1. Although certain strains of HIV-1 could enter syncytiotrophoblasts, the cells did not exhibit permissiveness for HIV-1. The next studies tested the possibility that placental macrophages might induce replication of HIV-1 carried in syncytiotrophoblast cells and that infected syncytiotrophoblasts would be capable of transmitting virus into neighbouring macrophages. For this purpose, the macrophage-tropic Ba-L strain of HIV-1 was used. Interactions between syncytiotrophoblasts and macrophages activated HIV-1 from latency in syncytiotrophoblast cells, which delivered HIV-1 to cocultured macrophages. The stimulatory effect of coculture on HIV-1 gene expression was mediated by marked tumor necrosis factor-, and interleukin-6 release from macrophages, an effect caused by contact between the different placental cells. Results suggest an interactive role for the syncytiotrophoblast layer and placental macrophages in the dissemination of HIV-1 among placental tissue. [source] Advanced molecular immunoassay system for immunobiotic lactic acid bacteria using a transfectant of Toll-like receptor 2ANIMAL SCIENCE JOURNAL, Issue 2 2007Masanori TOHNO ABSTRACT Toll-like receptor 2 (TLR2) is a receptor for a variety of microbial components, and it also mediates activation signals in the cell relating to the innate immune system. In order to evaluate the precise molecular immunoregulation by various strains of lactic acid bacteria (LAB) via TLR2, the swine TLR2 (sTLR2)-expressing transfectant was constructed using human embryonic kidney (HEK) 293 cells. It is demonstrated that intact immunobiotic LAB can induce immune responses through TLR2, and that different nuclear factor-,B (NF-,B) activities of various strains can be accurately detected by sTLR2-expressing HEK293 cells. Furthermore, cellular activation of NF-,B via TLR2 is reflected in enhanced binding and uptake of LAB. The sTLR2-expressing HEK293 cells were also useful for characterizing the expression pattern of type I helper T (Th1) and type II helper T (Th2) cytokines by the stimulation of immunobiotic LAB. These results suggest that sTLR2-expressing HEK293 cells may be useful in certain molecular immunoassay systems for producing new physiologically functional foods with intestinal immunomodulatory abilities, such as the maintenance of Th1/Th2 polarization. [source] Synthesis and antimicrobial activities of sulfonohydrazide-substituted 8-hydroxyquinoline derivative and its oxinatesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 5 2010Ritu B. Dixit Abstract Looking at the pharmacological importance of 8-hydroxyquinolines and sulfonamides, in the present study, a novel bi-dentate ligand 4-amino- N,-[(8-hydroxyquinoline-5-yl)methyl] benzenesulfonohydrazide (AHQMBSH) having above both moieties within a single molecular framework was synthesized by the reaction of N -acetamidobenzene sulfonohydrazide with 5-chloromethyl-8-hydroxyquinoline hydrochloride. Its metal(II) oxinates were also prepared with Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) salts. All the above compounds were investigated by physicochemical analyses, thermogravimetric analysis and spectroscopic techniques. Antimicrobial activities for the above prepared compounds were carried out using the agar-plate method against various strains of bacteria (Staphylococcus aureus, Bacillus subtillis, Pseudomonas aerugionsa, Escherichia coli) and fungi (Aspergillus niger and Aspergillus flavous). The results show a significant increase in antimicrobial and antifungal activities of AHQMBSH compared with the parent 8-hydroxyquinoline and sulfonamides. Copyright © 2010 John Wiley & Sons, Ltd. [source] Co-fermentation with Pichia kluyveri increases varietal thiol concentrations in Sauvignon BlancAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2009N. ANFANG Abstract Background and Aims:, Volatile varietal thiols are one class of yeast metabolite that add aroma/flavour to Sauvignon Blanc, particularly to the Marlborough style from New Zealand. While various strains of Saccharomyces cerevisiae are known to liberate such thiols, there are no data examining whether non- Saccharomyces species effect concentrations of these thiols in wine. Methods and Results:, We screened a variety of New Zealand wine yeast isolates and found some that were able to liberate either 3-mercaptohexan-1-ol (3MH) or 3-mercaptohexyl acetate (3MHA). We show that co-fermentation with specific commercial strains and an isolate of Pichia kluyveri from New Zealand, at a 1:9 starting ratio, significantly enhances the 3MHA concentrations in Sauvignon Blanc compared with single species ferments. Conclusions:, Co-fermentation with this isolate of P. kluyveri may provide a means to elevate 3MHA concentrations in Sauvignon Blanc; the mechanism behind this increase is unknown. Significance of the Study:, Techniques that allow the predictable manipulation of varietal thiols potentially provide tools for winemakers to alter wine style without the use of genetically modified organisms. [source] Induction of scratching behaviour and dermatitis in various strains of mice cohabiting with NC/Nga mice with chronic dermatitisBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2006Y. Hashimoto Summary Background, NC/Nga (NC) mice with similar pathological and behavioural features as seen in human atopic dermatitis are used as a model of the disease. Under normal circumstances, spontaneous and persistent scratching occurs in NC mice and this can lead to the onset of skin inflammation. Objectives, We examined the induction of scratching behaviour in NC, BALB/c, ICR and C3H/HeN mice, and of dermatitis in NC and BALB/c mice, by cohabitation with mice with dermatitis. Methods, NC, BALB/c, ICR and C3H/HeN mice were kept together with NC mice with chronic dermatitis (CNV-NC) for 2 weeks, and the numbers of scratching episodes were counted. NC and BALB/c mice were also kept together with CNV-NC mice for 24 weeks and the skin severity score was assessed. The score was assessed for a further 8 weeks after separation of these mice. Results, The number of scratching episodes in NC, BALB/c, ICR and C3H/HeN mice was increased by cohabitation with CNV-NC mice. Cohabitation with CNV-NC mice led to dermatitis in both NC and BALB/c mice. The number of scratching episodes and the skin severity score in BALB/c mice were about half of those in NC mice. When cohabitation with CNV-NC mice stopped, the number of scratching episodes and the skin severity score decreased in BALB/c mice, but not in NC mice. Changes in the histopathological data of BALB/c mice supported the severity of skin inflammation. Conclusions, Our study demonstrates that scratching behaviour and dermatitis can be induced in various strains of mice by cohabitation with CNV-NC mice, and that cessation of cohabitation leads to a recovery in BALB/c mice but not in NC mice. [source] Growth of Brucella abortus in macrophages from resistant and susceptible mouse strainsCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 2 2000J. Sathiyaseelan C57Bl/10 mice have a superior ability to control chronic infections with virulent strains of the intracellular bacteria Brucella abortus compared with BALB/c mice. While a number of differences in the cytokines produced by lymphocytes following infection of these two strains of mice have been shown, macrophages have not been evaluated for their role in conveying relative resistance. The importance of macrophages in control of brucella infections is demonstrated by the observations that intracellular survival of various strains of B. abortus directly correlates with their virulence in vivo, and the ability of macrophages to control brucellae in vitro has been shown to correlate with a brucella-resistant phenotype in ruminants. While both BALB/c and C57Bl are Nramp -susceptible mouse strains, additional differences in macrophage function outside of the Nramp1 gene effects could influence susceptibility to brucellosis. The studies conducted here comparing the ability of macrophages from C57Bl/10 and BALB/c mice indicate that the macrophages from resistant mice did not control intracellular growth of B. abortus strain 2308 more efficiently than those from the susceptible mice, either in the absence of, or following, interferon-gamma activation or iron supplementation. A number of different conditions for culturing macrophages were evaluated to rule out the influence of antibiotics on the conclusions drawn from the results. [source] | ||||||||||||||||