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Bacterial Strains (bacterial + strain)
Terms modified by Bacterial Strains Selected AbstractsThe Bactericidal Effects of Electrolyzed Oxidizing Water on Bacterial Strains Involved in Hospital InfectionsARTIFICIAL ORGANS, Issue 6 2004Nina V. Vorobjeva Abstract:, The study is designed to investigate bactericidal actions of electrolyzed oxidizing water on hospital infec-tions. Ten of the most common opportunistic pathogens are used for this study. Cultures are inoculated in 4.5 mL of electrolyzed oxidizing (EO) water or 4.5 mL of sterile deionized water (control), and incubated for 0, 0.5, and 5 min at room temperature. At the exposure time of 30 s the EO water completely inactivates all of the bacterial strains, with the exception of vegetative cells and spores of bacilli which need 5 min to be killed. The results indicate that electrolyzed oxidizing water may be a useful disinfectant for hospital infections, but its clinical application has still to be evaluated. [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] Detection of oral streptococci with collagen-binding properties in saliva specimens from mothers and their childrenINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 4 2010RYOTA NOMURA International Journal of Paediatric Dentistry 2010; 20: 254,260 Background., Approximately 10,20% of Streptococcus mutans strains have been reported to possess collagen-binding properties, whereas other species in the oral cavity with those properties remain to be elucidated. Aim., To identify strains with collagen-binding properties and analyse their characteristics in comparison with S. mutans. Design., A total of 110 expectorated saliva specimens were collected from 55 pairs of mothers and their children. Bacterial strains with collagen-binding properties were isolated and the species specified. In addition, strains with collagen-binding properties isolated from mother,child pairs were analysed using molecular biological approaches. Results., The detection frequency of strains with collagen-binding properties was shown to be 40.9%, among which S. salivarius was the most frequently detected, followed by S. mutans. The collagen-binding activity of the S. mutans group was the highest, followed by S. salivarius. In addition, S. mutans and S. salivarius strains from 3 and 1 mother,child pairs, respectively, were shown to be the same clones. Conclusions., Our results indicate that S. mutans and S. salivarius are major species with collagen-binding properties in the oral cavity, and that strains with such properties may be related to mother,child transmission. [source] Identification and characterization of enterococci from bryndza cheeseLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2006D. Jurkovi Abstract Aims:, To identify enterococci isolated from sheep milk cheese , bryndza, and to compare differences in the composition of enterococcal microflora affected by the season, and to evaluate the potential presence of vancomycin resistance and virulence determinants. Methods and Results:, Bacterial strains were isolated during analysis of bryndza cheese and identified on the genus and species level by phenotypic methods and with commercial biochemical sets. The identification of the species, Enterococcus faecium, Ent. durans and Ent. faecalis, was confirmed by PCR using species-specific primers for ddl genes. PCR was also used for assessment of presence of vanA and vanB genes and virulence determinants gelE, agg and cytolysin genes namely: cylLL, cylLS, cylM, cylB and cylA. Among 308 Enterococcus sp. strains, 177 isolates were proved to be Ent. faecium, 59 to be Ent. durans and 41 to be Ent. faecalis. Vancomycin resistance genes vanA and vanB were not detected. Agar plate testing confirmed their absence. Gene gelE, however, was found in 20 Ent. faecalis isolates, but only 13 of them showed gelatinase-positive phenotype. Seven isolates had five cytolysin genes, but none of the isolates exhibited a positive haemolytic phenotype. Four isolates possessed the agg gene. The prevalence of Ent. faecium species was highest in samples from the winter season harvest. Conclusions:,Ent. faecium is the dominant enterococcal species in bryndza cheese and the most prevalent in the winter season product. None of the Enterococcus sp. strains was proved to have vanA or vanB genes and the vancomycin resistance. Significance and Impact of the Study:, To our knowledge, this is the first report of enterococcal microflora in bryndza cheese and its evaluation for the presence of vanA and vanB genes as well as virulence determinants. [source] Industrial Potential of Organic Solvent Tolerant BacteriaBIOTECHNOLOGY PROGRESS, Issue 3 2004Yogita N. Sardessai Most bacteria and their enzymes are destroyed or inactivated in the presence of organic solvents. Organic solvent tolerant bacteria are a relatively novel group of extremophilic microorganisms that combat these destructive effects and thrive in the presence of high concentrations of organic solvents as a result of various adaptations. These bacteria are being explored for their potential in industrial and environmental biotechnology, since their enzymes retain activity in the presence of toxic solvents. This property could be exploited to carry out bioremediation and biocatalysis in the presence of an organic phase. Because a large number of substrates used in industrial chemistry, such as steroids, are water-insoluble, their bioconversion rates are affected by poor dissolution in water. This problem can be overcome by carrying out the process in a biphasic organic-aqueous fermentation system, wherein the substrate is dissolved in the organic phase and provided to cells present in the aqueous phase. In bioprocessing of fine chemicals such as cis -diols and epoxides using such cultures, organic solvents can be used to extract a toxic product from the aqueous phase, thereby improving the efficiency of the process. Bacterial strains reported to grow on and utilize saturated concentrations of organic solvents such as toluene can revolutionize the removal of such pollutants. It is now known that enzymes display striking new properties in the presence of organic solvents. The role of solvent-stable enzymes in nonaqueous biocatalysis needs to be explored and could result in novel applications. [source] Vectorization of Harungana madagascariensis Lam. ex Poir. (Hypericaceae) ethanolic leaf extract by using PLG-nanoparticles: antibacterial activity assessmentDRUG DEVELOPMENT RESEARCH, Issue 1 2005B. Moulari Abstract This study was undertaken to compare the in vitro and ex vivo antibacterial activity of an ethanolic Harungana madagascariensis leaf extract (HLE) incorporated into poly (D,L -lactide-co,glycolide) nanoparticles (HLE -PLG-NP). Two concentrations of HLE (500 and 1,000,µg/mL) for the in vitro study and one concentration (500 µg/mL) for the ex vivo study were compared using two gram-positive bacterial strains (Micrococcus luteus and Staphylococcus epidermidis), and one gram-negative bacterial strain (Moraxella sp.). The ex vivo antibacterial activity was evaluated on S. epidermidis CIP 55109 (SE) using an artificial contamination method. SE was inoculated for 12 h onto human skin fragment surfaces treated for 5,min either with HLE loaded, unloaded PLG-NP, or HLE solution. In vitro, the two preparations inhibited completely the growth of all bacterial strains at 1,000,µg/mL. However, the HLE -PLG-NP had a significant antibacterial activity against SE (18.4±1.8,0.4±0.2 CFU/mL, P<0.05), and a marked antibacterial effect against M. luteus (ML) and Moraxella sp. (Msp) compared to HLE solution at 500 µg/mL. Ex vivo, HLE -PLG-NP at 500,µg/mL reduced viable bacteria (6.3,4.8 log10), compared to the HLE solution (6.3,5.5 log10) after 4 h artificial contamination (P<0.05). A thin layer chromatography study of both HLE solution and HLE -PLG-NP showed that among the seven components found on the chromatogram of the HLE solution, only two were present on the nanoparticles, one including a flavonoid heteroside fraction responsible for the antibacterial properties. The incorporation of the HLE into a colloidal carrier improved antibacterial performance. Drug Dev. Res. 65:26,33, 2005. © 2005 Wiley-Liss, Inc. [source] Just how does the cII selection system work in MutaÔMouse?ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 4 2001Roy R. Swiger Abstract The lambda CII protein is an essential component in the lytic vs. lysogeny decision a bacteriophage makes upon infection of a host at low temperatures. The protein interacts with numerous phage promoters modulating the expression of the CI repressor, thus providing the mechanism for lysogenization soon after infection. The Big Blue® and MutaÔMouse are two widely used in vivo mutational model systems. The assays rely on retrievable lambda-based transgenes housing mutational targets (lacI or lacZ, respectively). The transgenes provide an elegant vehicle for the quantification of mutations sustained in virtually any tissue of the rodent. The use of the bacteriophage cII locus as an alternative, or additional mutational target for use with the Big Blue® rodent system was first reported by Jakubczak et al. ([1996]: Proc Natl Acad Sci USA 93:9073,9078). More recently, this selection assay has been applied successfully to the MutaÔMouse (Swiger et al. [1999]: Environ Mol Mutagen 33:201,207). The use of an Hfl bacterial strain and low temperature allows the determination of mutations sustained at the cII locus in either system, with high fidelity. The cII selection assay in the Big Blue® relies on the presence of the lambda repressor protein CI. In contrast, the recombinant construct used to make the MutaÔMouse transgene lacks functional CI protein. Nevertheless, we report an excellent system for quantifying mutations at the cII locus in MutaÔMouse. Just how does cII selection work in the MutaÔMouse? Written in the context of lambda recombinant genetics, this paper explores the question further. Environ. Mol. Mutagen. 37:290,296, 2001 © 2001 Wiley-Liss, Inc. [source] Microbiological evaluation of toxicity of three polycyclic aromatic hydrocarbons and their decomposition products formed by advanced oxidation processesENVIRONMENTAL TOXICOLOGY, Issue 3 2003Teresa Jamroz Abstract The toxicity of benzo[a]pyrene, chrysene, and fluorene and their decomposition products formed by advanced oxidation processes (AOPs) was investigated using biotests with Escherichia coli and Vibrio fischeri. The polycyclic aromatic hydrocarbons (PAHs) were not highly toxic to either bacterial strain; the toxicity of their degradation products depended on the method of chemical processing. Inhibition of more than 27% was observed with products formed by oxidation of the PAHs, by AOP methods without hydrogen peroxide. Toxicity as high as 100% was observed after the combined action of hydrogen peroxide and other oxidizing agents. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 187,191, 2003 [source] Arsenic Binding to Iron(II) Minerals Produced by An Iron(III)-Reducing Aeromonas Strain Isolated from Paddy SoilENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2009Xin-Jun Wang Abstract An iron-reducing bacterial strain was isolated from a paddy soil and identified as a member of the Aeromonas group by 16S rRNA gene sequence analysis. When the cells were growing with dissolved Fe(III) as the electron acceptor in the presence of As(V), Fe(II) minerals (siderite and vivianite) were formed and dissolved. As was removed efficiently from solution. When the cells were growing with the Fe(III) hydroxide mineral (ferrihydrite) as the electron acceptor in the presence of As(V), ferrihydrite was reduced and dissolved As(V) concentrations decreased sharply. The present study results demonstrated first that members of the Aeromonas group can reduce Fe(III) in paddy soils and second that iron reduction does not necessarily lead to arsenic mobilization. However, As immobilization can occur in environments that contain significant concentrations of counterions such as bicarbonate and phosphate. [source] Degradation products of a phenylurea herbicide, diuron: Synthesis, ecotoxicity, and biotransformationENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2001Céline Tixier Abstract The degradation products of diuron (photoproducts and metabolites), already described in the literature, were synthesized in order to carry out further investigations. Their ecotoxicity was determined using the standardized Microtox® test, and most of the derivatives presented a nontarget toxicity higher than that of diuron. Therefore, the biotransformation of these compounds was tested with four fungal strains and a bacterial strain, which were known to be efficient for diuron transformation. With the exception of the 3,4-dichlorophenylurea, all the degradation products underwent other transformations with most of the strains tested, but no mineralization was observed. For many of them, the biodegradation compound for which the toxicity was important was 3,4-dichlorophenylurea. This study underlines the importance of knowing the nature of the degradation products, which has to be kept in mind while analyzing natural water samples or soil samples. [source] Expression of mitochondrial HMGCoA synthase and glutaminase in the colonic mucosa is modulated by bacterial speciesFEBS JOURNAL, Issue 1 2004Claire Cherbuy The expression of the colonic mitochondrial 3-hydroxy 3-methyl glutaryl CoA (mHMGCoA) synthase, a key control site of ketogenesis from butyrate, is lower in germ-free (GF) than in conventional (CV) rats. In contrast, the activity of glutaminase is higher. The objective of this study was to investigate whether the intestinal flora can affect gene expression through short chain fatty acid (SCFA) and butyrate production. GF rats were inoculated with a conventional flora (Ino-CV) or with a bacterial strain producing butyrate (Clostridium paraputrificum, Ino- Cp) or not (Bifidobacterium breve, Ino- Bb). In the Ino-CV rats, mHMGCoA synthase expression was restored to the CV values 2 days after the inoculation, i.e. concomitantly with SCFA production. In the Ino- Cp group, but not in the Ino- Bb group, mHMGCoA synthase and glutaminase were expressed at the level observed in the CV rats. These data suggest that the intestinal flora, through butyrate production, could control the expression of colonic mHMGCoA synthase and glutaminase. These modifications in gene expression by butyrate in vivo seem unrelated to a modification of histone acetylation. [source] Mucilaginibacter dorajii sp. nov., isolated from the rhizosphere of Platycodon grandiflorumFEMS MICROBIOLOGY LETTERS, Issue 2 2010Byung-Chun Kim Abstract A Gram-negative, nonmotile and rod-shaped bacterial strain was isolated from the rhizosphere of Platycodon grandiflorum in a study of bacterial diversity, and its taxonomic position was investigated by a genotypic and phenotypic analysis. This isolate, designated as DR-f4, grew at 4,30 °C (optimally at 20,25 °C) and in the presence of 0,1% (w/v) NaCl. It contained MK-7 as the predominant menaquinone. The isolate had activities of catalase, oxidase and ,-galactosidase and hydrolyzed aesculin, casein, carboxymethyl-cellulose, starch and l -tyrosine. The major cellular fatty acids were summed feature 3 (C16:1,7c and/or iso-C15:0 2OH) and iso-C15:0. The DNA G+C content was 42.6 mol%. This isolate belonged to the genus Mucilaginibacter based on phylogenetic analysis using 16S rRNA gene sequences. The nearest phylogenetic neighbors of strain DR-f4T were Mucilaginibacter lappiensis ANJL12T and Mucilaginibacter rigui WPCB133T, with 16S rRNA gene sequence similarity levels of 96.9% and 96.4%, respectively. The genotypic and phenotypic evidence suggests that strain DR-f4T should be classified as a novel species, for which the name Mucilaginibacter dorajii sp. nov. is proposed. The type strain for the novel species is DR-f4T (=KACC 14556T=JCM 16601T). [source] CD4+ T lymphocytes mediate colitis in HLA-B27 transgenic rats monoassociated with nonpathogenic Bacteroides vulgatusINFLAMMATORY BOWEL DISEASES, Issue 3 2007Frank Hoentjen MD Abstract Background: HLA-B27/,2 microglobulin transgenic (TG) rats develop spontaneous colitis when raised under specific pathogen-free (SPF) conditions or after monoassociation with Bacteroides vulgatus (B. vulgatus), whereas germ-free TG rats fail to develop intestinal inflammation. SPF HLA-B27 TG rnu/rnu rats, which are congenitally athymic, remain disease free. These results indicate that commensal intestinal bacteria and T cells are both pivotal for the development of colitis in TG rats. However, it is not known if T cells are also required in the induction of colitis by a single bacterial strain. The aim of this study was therefore to investigate the role of T cells in the development of colitis in B. vulgatus,monoassociated HLA-B27 TG rats. Methods: HLA-B27 TG rnu/rnu and rnu/+ rats were monoassociated with B. vulgatus for 8,12 weeks. CD4+ T cells from mesenteric lymph nodes (MLNs) of B. vulgatus,monoassociated rnu/+ TG donor rats were transferred into B. vulgatus,monoassociated rnu/rnu TG recipients. Results:B. vulgatus,monoassociated rnu/+ rats showed higher histologic inflammatory scores and elevated colonic interferon-, mRNA, cecal myeloperoxidase, and cecal IL-1, levels compared to those in rnu/rnu TG rats that did not contain T cells. After transfer of CD4+ cells from colitic B. vulgatus,monoassociated rnu/+ TG donor rats, B. vulgatus,monoassociated rnu/rnu TG recipients developed colitis that was accompanied by B. vulgatus- induced IFN-, production by MLN cells in vitro and inflammatory parameters similar to rnu/+ TG rats. Conclusions: These results implicate CD4+ T cells in the development of colitis in HLA-B27 TG rats monoassociated with the nonpathogenic bacterial strain B. vulgatus. (Inflamm Bowel Dis 2007) [source] Nutritional evaluation of fermented black gram (Phaseolus mungo) seed meal in compound diets for rohu, Labeo rohita (Hamilton), fingerlingsJOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2007S. Ramachandran Summary Six isonitrogenous (approximately 35% crude protein) and isocaloric (approximately 4.0 kcal g,1) diets were formulated incorporating raw and fermented black gram, Phaseolus mungo, seed meal at 20%, 30% and 40% levels by weight into a fishmeal-based control diet fed to rohu, Labeo rohita, fingerlings (mean weight, 1.81 ± 0.21 g) for 80 days for a study of fish performance. A particular bacterial strain (Bacillus sp.) isolated from the intestine of adult common carp (Cyprinus carpio) reared in the wild having significant amylolytic, cellulolytic, lipolytic and proteolytic activities was used for fermentation of seed meal for 15 days at 37 ± 2°C. Fermentation of P. mungo seed meal was effective in significantly reducing the crude fibre content and antinutritional factors such as tannins and phytic acid, and enhancing available free amino acids and fatty acids. In terms of growth, feed conversion ratio and protein efficiency ratio, the 30% fermented black gram seed meal incorporated diet resulted in a significantly (P < 0.05) better performance of rohu fingerlings. In general, growth and feed utilization efficiencies of diets containing fermented seed meal were superior to diets containing raw seed meal. The apparent protein digestibility (APD) values decreased with increasing levels of raw seed meal in the diets. The APD for raw seed meal was lower at all levels of inclusion in comparison to those for the fermented seed meals. The maximum deposition of protein in the carcass was recorded in fish fed the diet containing 40% fermented seed meal. The results indicate that fermented black gram seed meal can be incorporated in carp diets up to the 30% level compared to the 10% level of raw seed meal. [source] Utilization of oligo- and polysaccharides at microgram-per-litre levels in freshwater by Flavobacterium johnsoniaeJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2010E.L.W. Sack Abstract Aims:, To obtain a bacterial strain that can be used to quantify biodegradable polysaccharides at concentrations of a few micrograms per litre in freshwater. Methods and Results:,Flavobacterium johnsoniae strain A3 was isolated from tap water supplemented with laminarin, pectin or amylopectin at 100 ,g C l,1 and river Rhine water. The organism utilized 14 of 23 oligo- and polysaccharides, and 1 of 9 monosaccharides, but none of the sugar acids, sugar alcohols, carboxylic acids or aromatic acids tested at 10 ,g C l,1. Amino acids promoted growth of strain A3, but not in coculture with assimilable organic carbon (AOC) test strain Pseudomonas fluorescens P17, which utilized these compounds more rapidly than strain A3. Compounds released by strain P17 and AOC test strain Spirillum sp. NOX grown on acetate promoted the growth of strain A3 at Nmax values of , 2 × 105 CFU ml,1 of strain P17 and , 5 × 105 CFU ml,1 of strain NOX. Significant growth of strain A3 was observed in surface water and in tap water in the presence of strain P17 (Nmax P17 < 2 × 105 CFU ml,1). Conclusions:, Strain A3 utilizes oligo- and polysaccharides at microgram-per-litre levels. In surface water and in tap water, the organism was able to utilize compounds that were not utilized by strain P17. These compounds may include oligo- and/or polysaccharides. Significance and Impact of the Study:, Phytoplanktonic and bacterial polysaccharides can constitute an important biodegradable fraction of natural organic matter in water and may promote growth of heterotrophic bacteria during water treatment and drinking water distribution. Strain A3 can be used to quantify a group of compounds that includes oligo- and polysaccharides at microgram-per-litre levels in freshwater. [source] Characterization of specific egg yolk immunoglobulin (IgY) against mastitis - causing Staphylococcus aureusJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2008Y.-H. Zhen Abstract Aims:, To evaluate the in vitro activity of egg yolk immunoglobulin (IgY) against mastitis-causing Staphylococcus aureus. Methods and Results:, Specific IgY was produced by immunizing hens with formaldehyde-killed Staph. aureus, using a bacterial strain known to cause mastitis. The IgY, of 94% purity, was obtained from yolks by water dilution, salt precipitations, ultrafiltration and gel filtration. ELISA indicated that the IgY produced was specific to the antigen and five Staph. aureus isolates obtained from mastitic cows. The growth of Staph. aureus was inhibited by specific IgY at concentrations from 1 to 10 mg ml,1 in a dose-dependent manner. The phagocytosis of Staph. aureus by milk macrophages was enhanced in the presence of specific IgY with the highest phagocytic percentage being 30% higher than that without IgY (P < 0·05). Conclusions:, The specific IgY against mastitis-causing Staph. aureus inhibited the growth of Staph. aureus and enhanced the phagocytosis of Staph. aureus by milk macrophages. Significance and Impact of the Study:, Specific IgY would be a potential treatment for bovine mastitis. [source] Isolation and characterization of a bacterial strain of the genus Ochrobactrum with methyl parathion mineralizing activityJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2006X.-H. Qiu Abstract Aims:, To isolate and characterize a methyl parathion (MP)-mineralizing bacterium, and to elucidate the degradative pathway of MP and localize the responsible degrading genes. Methods and Results:, A bacterial strain, designated B2, capable of mineralizing MP was isolated from the MP-polluted soil. Analysis of the 16S rRNA gene sequence and phenotypic analysis suggested that strain B2 had a close relationship with Ochrobactrum anthropi. B2 could totally degrade MP and four metabolites [p -nitrophenol (PNP), 4-nitrocatechol (4-NC), 1,2,4-benzenetriol (BT) and hydroquinone (HQ)] were identified by HPLC and gas chromatography-mass spectrometry analyses. Plasmid curing of strain B2 resulted in the loss of ability of B2 to degrade PNP, but not the ability to hydrolyse MP. Conclusions:,Ochrobactrum sp. B2 can mineralize MP rapidly via PNP, 4-NC, BT and HQ pathway. B2 harbours a plasmid encoding the ability to degrade PNP, while MP-hydrolysing activity is encoded on the bacterial chromosome. Significance and Impact of the Study:, This new bacterial strain (B2) capable of mineralizing MP will be useful in a pure-culture remediation process of organophosphate pesticides and their metabolites such as nitroaromatics. [source] Acinetobacter bioreporter assessing heavy metals toxicityJOURNAL OF BASIC MICROBIOLOGY, Issue 5 2006Desouky Abd-El-Haleem Dr. This work was conducted to employ a whole cell-based biosensor to monitor toxicity of heavy metals in water and wastewater. An isolate of industrial wastewater bacterium, Acinetobacter sp. DF4, was genetically modified with lux reporter gene to create a novel bioluminescent bacterial strain, designated as DF4/PUTK2. This bioreporter can investigate the toxicity through light inhibition due to cell death or metabolic burden and the specific stress effects of the tested soluble materials simultaneously. The use of Acinetobacter DF4/PUTK2 as a bioluminescent reporter for heavy metal toxicity testing and for the application of wastewater treatment influent toxicity screening is presented in this study. Among eight heavy metals tested, the bioluminescence of DF4/PUTK2 was most sensitive to Zn, Cd, Fe, Co, Cr followed by Cu in order of decreasing sensitivity. The same pattern of sensitivity was observed when several contaminated water and wastewater effluents were assayed. This work suggested that luxCDABE -marked Acinetobacter bacterium DF4/PUTK2 can be used to bioassay the ecotoxicity of wastewater and effluent samples contaminated with heavy metals. Using this assay, it is possible to pre-select the more toxic samples for further chemical analysis and to discard wastewater samples with low or no inhibition because they are not toxic to the environment. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Batch and continuous studies on treatment of pulp mill wastewater by Aeromonas formicansJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2001K Gupta Abstract Batch and continuous studies have been conducted on the treatment of black liquor from a kraft pulp and paper mill by a bacterial strain, Aeromonas formicans. The results of batch studies revealed that the strain was able to remove 71% and 78% of COD and lignin respectively, while the colour removal efficiency was around 86% in 10 days of retention time. The analysis of lignin degradation products by gas chromatography after 20 days of incubation revealed the formation of some phenolic acids, which were responsible for the decrease in pH during batch studies. The removal efficiencies of COD, colour and lignin obtained in continuous reactor studies were 73, 88 and 77% respectively for an 8 day detention period and these efficiencies were almost the same as obtained in batch studies. © 2001 Society of Chemical Industry [source] Increase of Conjugated Linoleic Acid Content in Milk by Fermentation with Lactic Acid BacteriaJOURNAL OF FOOD SCIENCE, Issue 5 2002Y.J. Kim ABSTRACT: The objectives of this study were to identify the factors and procedures responsible for increasing the conjugated linoleic acid (CLA) content in fermented milk. Fourteen lactic acid bacteria were screened for CLA-producing ability using sunflower oil (containing 70% linoleic acid) as a substrate. Among the screened strains, Lactococcus lactis I-01 showed the highest CLA-producing ability. The optimal concentration of sunflower oil for CLA production was 0.1 g/L in whole milk, which accounted for 0.25% of total milk fat. Our results demonstrated that CLA formation in fermented milk could be affected by numerous factors such as bacterial strain, cell number, optimal substrate concentration, and the period of incubation at neutral pH. [source] Antioxidative capacity produced by Bifidobacterium - and Lactobacillus acidophilus -mediated fermentations of konjac glucomannan and glucomannan oligosaccharidesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2008Cheng-Hsin Wang Abstract BACKGROUND: Konjac glucomannan (KGM) has been shown to stimulate the growth of bifidobacteria and lactobacilli in the human and rat colon. This study investigated the antioxidative effects produced after 48 h in vitro fermentation of unhydrolysed KGM and two hydrolysed KGM fractions (KH1 and KH2 with degree of polymerisation 10 and 5 respectively) by Bifidobacterium adolescentis, B. bifidum, B. breve, B. longum and Lactobacillus acidophilus respectively. The inhibitory effect on conjugated diene formation, ferric-chelating capacity, ,,,-diphenyl-,-picrylhydrazyl (DPPH) radical-scavenging ability and thiobarbituric acid-reactive substances (TBARS) concentration produced by these fermentations were compared with those of oligofructose (OF) fermentation. RESULTS: The fermentation of KGM by each bacterial strain produced higher ferric-chelating capacity of the culture supernatant compared with KH2 or OF fermentation. In contrast, the fermentation of KGM by each bacterial strain led to lower inhibition of conjugated diene formation and lower radical-scavenging ability compared with KH2 fermentation. The fermentation of KH2 produced the lowest amount of TBARS. CONCLUSION: The fermentation of unhydrolysed KGM by colonic lactic acid bacteria in vitro produced antioxidative capacity mainly by preventing the initiation of ferrous ion-induced peroxidation, whereas the fermentation of konjac oligosaccahrides did so by increasing the radical-scavenging ability and eliminating lipid peroxide formation. Copyright © 2008 Society of Chemical Industry [source] The influence of malolactic fermentation and Oenococcus oeni strain on glycosidic aroma precursors and related volatile compounds of red wineJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2006Maurizio Ugliano Abstract Free and glycosidically bound volatile compounds of red wine were measured after malolactic fermentation (MLF) with four different commercial starter cultures of Oenococcus oeni. MLF resulted in a significant decrease in the concentration of total glycosides, expressed as phenol-free glycosyl glucose. Gas chromatographic analyses of wine enzyme hydrolysates showed that the extent of hydrolysis of glycosides during MLF was dependent on both bacterial strain and chemical structure of the substrate. The highest decrease was observed for glycosidic precursors of primary terpene alcohols. Glycoside-related aroma compounds such as linalool, farnesol, and ,-damascenone were increased after MLF with all the bacterial strains tested. Two of the strains were also able to release significant amounts of vinylphenols during MLF. Copyright © 2006 Society of Chemical Industry [source] pFARs, Plasmids free of antibiotic resistance markers, display high-level transgene expression in muscle, skin and tumour cellsTHE JOURNAL OF GENE MEDICINE, Issue 4 2010Corinne Marie Abstract Background Nonviral gene therapy requires a high yield and a low cost production of eukaryotic expression vectors that meet defined criteria such as biosafety and quality of pharmaceutical grade. To fulfil these objectives, we designed a novel antibiotic-free selection system. Methods The proposed strategy relies on the suppression of a chromosomal amber mutation by a plasmid-borne function. We first introduced a nonsense mutation into the essential Escherichia coli thyA gene, resulting in thymidine auxotrophy. The bacterial strain was optimized for the production of small and novel plasmids free of antibiotic resistance markers (pFARs) and encoding an amber suppressor t-RNA. Finally, the potentiality of pFARs as eukaryotic expression vectors was assessed by monitoring luciferase activities after electrotransfer of LUC-encoding plasmids into various tissues. Results The introduction of pFARs into the optimized bacterial strain restored normal growth to the auxotrophic mutant and allowed an efficient production of monomeric supercoiled plasmids. The electrotransfer of LUC-encoding pFAR into muscle led to high luciferase activities, demonstrating an efficient gene delivery. In transplanted tumours, transgene expression levels were superior after electrotransfer of the pFAR derivative compared to a plasmid carrying a kanamycin resistance gene. Finally, in skin, whereas luciferase activities decreased within 3 weeks after intradermal electrotransfer of a conventional expression vector, sustained luciferase expression was observed with the pFAR plasmid. Conclusions Thus, we have designed a novel strategy for the efficient production of biosafe plasmids and demonstrated their potentiality for nonviral gene delivery and high-level transgene expression in several tissues. Copyright © 2010 John Wiley & Sons, Ltd. [source] Identification and Repair of Positive Binding Antibodies Containing Randomly Generated Amber Codons from Synthetic Phage Display LibrariesBIOTECHNOLOGY PROGRESS, Issue 3 2006Warren D. Marcus Phage display technology allows for the rapid isolation and characterization of monoclonal antibodies that have vast potential for therapeutic and diagnostic applications. However, the panning process, which utilizes a host strain that suppresses termination by the amber codon, has an inherent bias toward clones containing randomly generated amber stop codons, complicating identification of positive binding antibodies when the antibody genes are finally expressed in a nonsupressor host. Here, we perform biopanning against a Histone 2A peptide using streptavidin- or anti-biotin-coated beads. After four rounds, a dominant clone is characterized but contains a spurious amber stop codon. A protocol is given that readily corrects the amber codon, allowing for soluble antibody production once the phagemid is transformed into a nonsuppressor bacterial strain. This work also highlights the ability to isolate antibodies against a protein antigen by using only a small peptide (15 amino acids) representing a portion of the antigen. [source] Helicobacter pylori,host cell interactions mediated by type IV secretionCELLULAR MICROBIOLOGY, Issue 7 2005Kevin M. Bourzac Summary Helicobacter pylori is a human-specific gastric pathogen that colonizes over half the world's population. Infection with this bacterium is associated with a spectrum of gastric pathologies ranging from mild gastritis to peptic ulcers and gastric cancer. A strong predictor of severe disease outcome is infection with a bacterial strain harbouring the cag (cytotoxin associated gene) pathogenicity island (PAI), a 40 kb stretch of DNA that encodes homologues of several components of a type IV secretion system (TFSS). One gene within the cag PAI, cagA, has been shown to encode a substrate for the TFSS which is translocated into host cells and causes multiple changes in host cell signalling. Here we review recent advances in the characterization of type IV secretion, the activities of CagA and CagA-independent effects of the TFSS, which are contributing to our understanding of H. pylori pathogenesis. [source] Molecular epidemiology of the nasal colonization by methicillin-susceptible Staphylococcus aureus in Swiss childrenCLINICAL MICROBIOLOGY AND INFECTION, Issue 9 2010C. Mégevand Clin Microbiol Infect 2010; 16: 1414,1420 Abstract Nasal carriage of Staphylococcus aureus contributes to an increased risk of developing an infection with the same bacterial strain. Genetic regulatory elements and toxin-expressing genes are virulence factors associated with the pathogenic potential of S. aureus. We undertook an extensive molecular characterization of methicillin-susceptible S. aureus (MSSA) carried by children. MSSA were recovered from the nostrils of children. The presence of Panton-Valentine leukocidin (PVL), exfoliatins A and B (exfoA and exfoB), and the toxic-shock staphylococcal toxin (TSST-1) and agr group typing were determined by quantitative PCR. A multiple-locus variable-number of tandem repeat analysis (MLVA) assay was also performed for genotyping. Five hundred and seventy-two strains of MSSA were analysed. Overall, 30% were positive for toxin-expressing genes: 29% contained one toxin and 1.6% two toxins. The most commonly detected toxin gene was tst, which was present in 145 (25%) strains. The TSST-1 gene was significantly associated with the agr group 3 (OR 56.8, 95% CI 32.0,100.8). MLVA analysis revealed a large diversity of genetic content and no clonal relationship was demonstrated among the analysed MSSA strains. Multilocus sequence typing confirmed this observation of diversity and identified ST45 as a frequent colonizer. This broad diversity in MSSA carriage strains suggests a limited selection pressure in our geographical area. [source] Topical antibiotics: therapeutic value or ecologic mischief?DERMATOLOGIC THERAPY, Issue 5 2009James Q. Del Rosso ABSTRACT Based on antibiotic prescribing data from 2003, dermatologists account annually for 8,9 million prescriptions for oral antibiotics, and 3,4 million prescriptions for topical antibiotics. Overall, much of the emphasis on concerns related to emergence of clinically significant antibiotic-resistant bacterial strains focuses on use of systemic antibiotics, however, topical antibiotic use may also have potential implications. The following article discusses the perspectives of the authors related to the potential therapeutic benefits and ecologic implications ("ecologic mischief") of topical antibiotic therapy for specific indications encountered in ambulatory dermatology practice. [source] Vectorization of Harungana madagascariensis Lam. ex Poir. (Hypericaceae) ethanolic leaf extract by using PLG-nanoparticles: antibacterial activity assessmentDRUG DEVELOPMENT RESEARCH, Issue 1 2005B. Moulari Abstract This study was undertaken to compare the in vitro and ex vivo antibacterial activity of an ethanolic Harungana madagascariensis leaf extract (HLE) incorporated into poly (D,L -lactide-co,glycolide) nanoparticles (HLE -PLG-NP). Two concentrations of HLE (500 and 1,000,µg/mL) for the in vitro study and one concentration (500 µg/mL) for the ex vivo study were compared using two gram-positive bacterial strains (Micrococcus luteus and Staphylococcus epidermidis), and one gram-negative bacterial strain (Moraxella sp.). The ex vivo antibacterial activity was evaluated on S. epidermidis CIP 55109 (SE) using an artificial contamination method. SE was inoculated for 12 h onto human skin fragment surfaces treated for 5,min either with HLE loaded, unloaded PLG-NP, or HLE solution. In vitro, the two preparations inhibited completely the growth of all bacterial strains at 1,000,µg/mL. However, the HLE -PLG-NP had a significant antibacterial activity against SE (18.4±1.8,0.4±0.2 CFU/mL, P<0.05), and a marked antibacterial effect against M. luteus (ML) and Moraxella sp. (Msp) compared to HLE solution at 500 µg/mL. Ex vivo, HLE -PLG-NP at 500,µg/mL reduced viable bacteria (6.3,4.8 log10), compared to the HLE solution (6.3,5.5 log10) after 4 h artificial contamination (P<0.05). A thin layer chromatography study of both HLE solution and HLE -PLG-NP showed that among the seven components found on the chromatogram of the HLE solution, only two were present on the nanoparticles, one including a flavonoid heteroside fraction responsible for the antibacterial properties. The incorporation of the HLE into a colloidal carrier improved antibacterial performance. Drug Dev. Res. 65:26,33, 2005. © 2005 Wiley-Liss, Inc. [source] Critical aspects of analysis of Micrococcus luteus, Neisseria cinerea, and Pseudomonas fluorescens by means of capillary electrophoresisELECTROPHORESIS, Issue 18-19 2004Verena Hoerr Abstract Within the frame of our study we investigated Microccocus luteus, Neisseria cinerea, and Pseudomonas fluorescens by means of capillary zone electrophoresis (CZE). They form chains and clusters on a different scale, which can be reflected in the electropherograms. A low buffer concentration of Tris-borate and Na2 EDTA containing a polymeric matrix of 0.0125% poly(ethylene) oxide (PEO) was used. Key factors were the standardization and optimization of CE conditions, buffer solution, and pretreatment of bacterial samples, which are not transferable to different bacterial strains, in general. The different compositions of the cell wall of on the one hand Gram-positive (M. luteus) and Gram-negative (N. cinerea) cocci and on the other hand Gram-negative, rod-shaped bacteria (P.fluorescens), are probably responsible for the different pretreatment conditions. [source] Screening, Characterization and Application of Cyanide-resistant Nitrile HydratasesENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 6 2004T. Gerasimova Abstract Two new bacterial strains, Pseudomonas marginales MA32 and Pseudomonas putida MA113, containing nitrile hydratases resistant to cyanide were isolated from soil samples by an enrichment procedure. In contrast to known nitrile hydratases, which rapidly lose activity at low to moderate cyanide concentrations, the enzymes described in this paper tolerate up to 50 mM cyanide. They show a broad substrate spectrum including not only small substrates like acrylonitrile but also nitriles with longer side chains and even nitriles with quarternary alpha-carbon atoms. Both characteristics are essential for the transformation of ketone cyanohydrins, which are much more instable and therefore releasing much higher amounts of prussic acid than cyanohydrins formed from aldehydes. P. marginales MA32 was used as a whole cell biocatalyst for the hydration of acetone cyanohydrin to ,-Hydroxyisobutyramide, which is a precursor of methacrylamide, an important pre-polymer. After optimization of the process conditions a maximum amide concentration of more than 1.6 M could be reached within 5 hours with 5,g/L biocatalyst referred to cell dry weight. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||