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Strains Isolated (strain + isolated)
Kinds of Strains Isolated Selected AbstractsCYTOTOXICITY ASSESSMENT OF BACILLUS STRAINS ISOLATED FROM STREET-VENDED FOODS IN JOHANNESBURG, SOUTH AFRICAJOURNAL OF FOOD SAFETY, Issue 2 2002F.M. MOSUPYE ABSTRACT Twenty-one isolates each of Bacillus (B.) cereus, B. licheniformis and B. subtilis from street foods, collected in central Johannesburg, were randomly selected to test for cytotoxicity against McCoy 5A Mouse cells using a 3-(4,5-dimethylthizol-2-yl)-2,5-diphenyltetrazolium bromide assay, and observation by confocal scanning laser microscopy (CSLM) and scanning electron microscopy (SEM). Forty-eight percent of B. cereus, 33% of B. licheniformis and 19% of B. subtilis strains produced cytotoxic compounds. For B. cereus strains, all supernatants exhibiting cytotoxic effects were inactivated by heat treatment at 121C for 15 min. By contrast, 24% of B. licheniformis and 10% of B. subtilis supernatants exhibited cytotoxic effects following heat treatment. CSLM and SEM showed that McCoy cells treated with cytotoxic supernatants exhibited leakage and necrosis. Presence of B. cereus, B. licheniformis and B. subtilis in street foods in high numbers may pose potetnial safety risks due to production of cytotoxic compounds. [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] The occurrence of Campylobacter in river water and waterfowl within a watershed in southern Ontario, CanadaJOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2010M.I. Van Dyke Abstract Aims:, Quantitative PCR and a culture method were used to investigate Campylobacter occurrence over 3 years in a watershed located in southern Ontario, Canada that is used as a source of drinking water. Methods and Results:, Direct DNA extraction from river water followed by quantitative PCR analysis detected thermophilic campylobacters at low concentrations (<130 cells 100 ml,1) in 57,79% of samples taken from five locations. By comparison, a culture-based method detected Campylobacter in 0,23% of samples. Water quality parameters such as total Escherichia coli were not highly correlated with Campylobacter levels, although higher pathogen concentrations were observed at colder water temperatures (<10°C). Strains isolated from river water were primarily nalidixic acid-susceptible Campylobacter lari, and selected isolates were identified as Campylobacter lari ssp. concheus. Campylobacter from wild birds (seagulls, ducks and geese) were detected at a similar rate using PCR (32%) and culture-based (29%) methods, and although Campylobacter jejuni was isolated most frequently, C. lari ssp. concheus was also detected. Conclusions:,Campylobacter were frequently detected at low concentrations in the watershed. Higher prevalence rates using quantitative PCR was likely because of the formation of viable but nonculturable cells and low recovery of the culture method. In addition to animal and human waste, waterfowl can be an important contributor of Campylobacter in the environment. Significance and Impact of the Study:, Results of this study show that Campylobacter in surface water can be an important vector for human disease transmission and that method selection is important in determining pathogen occurrence in a water environment. [source] Optimization of culture conditions for glucose oxidase production by a Penicillium chrysogenum SRT 19 strainENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 1 2010Ragini G. Bodade Abstract The enzyme glucose oxidase (GOD) has been used for a variety of biotechnological applications in food and pharmaceutical industries. In this study, the optimization of extracellular GOD production was carried out in a Penicillium chrysogenum SRT 19 strain isolated from contaminated and decaying cheese samples. Maximum GOD production was attained at pH 6 and 20°C in fermentation broth after 72,h of incubation. The effects of metal ions and sugars were screened for the induction of higher GOD production. The results revealed that glucose and lactose give the highest production of enzyme (0.670 and 0.552,U/mL, respectively) as compared with other sugars (sucrose, cellulose, mannitol and fructose). Out of the seven metal ions studied, CaCO3 (1.123,U/mL) and FeSO4 (0.822,U/mL) act as modulators, while MgSO4 (0.535,U/mL), CuSO4 (0.498,U/mL), HgCl2 (0.476,U/mL), ZnSO4 (0.457,U/mL) and BaSO4 (0.422,U/mL) yield lower production. The study therefore suggests that a strain of P. chrysogenum SRT 19 can be used as a new strain for GOD production. [source] Novel natural parabens produced by a Microbulbifer bacterium in its calcareous sponge host Leuconia niveaENVIRONMENTAL MICROBIOLOGY, Issue 6 2009Elodie Quévrain Summary A broad variety of natural parabens, including four novel structures and known ethyl and butyl parabens, were obtained from culture of a Microbulbifer sp. bacterial strain isolated from the temperate calcareous marine sponge Leuconia nivea (Grant 1826). Their structures were elucidated from spectral analysis, including mass spectrometry and 1D and 2D nuclear magnetic resonance. Their antimicrobial activity evaluated against Staphylococcus aureus was characterized by much higher in vitro activity of these natural paraben compounds 3,9 than commercial synthetic methyl and propyl parabens, usually used as antimicrobial preservatives. Compounds 4 and 9 revealed a bacteriostatic effect and compounds 6 and 7 appeared as bactericidal compounds. Major paraben compound 6 was also active against Gram positive Bacillus sp. and Planococcus sp. sponge isolates and was detected in whole sponge extracts during all seasons, showing its persistent in situ production within the sponge. Moreover, Microbulbifer sp. bacteria were visualized in the sponge body wall using fluorescence in situ hybridization with a probe specific to L4-n2 phylotypes. Co-detection in the sponge host of both paraben metabolites and Microbulbifer sp. L4-n2 indicates, for the first time, production of natural parabens in a sponge host, which may have an ecological role as chemical mediators. [source] A strain isolated from gas oil-contaminated soil displays chemotaxis towards gas oil and hexadecaneENVIRONMENTAL MICROBIOLOGY, Issue 10 2003Mariana P. Lanfranconi Summary In this report we describe the isolation of a strain from soil contaminated with gas oil by taking bacteria from a chemotactic ring on gas oil-containing soft agar plates. Partial 16 S rDNA sequencing of the isolated strain showed 99.1% identity with Flavimonas oryzihabitans. It was not only able to degrade different aliphatic hydrocarbons but it was also chemotactic towards gas oil and hexadecane, as demonstrated by the use of three different chemotaxis methods, such as agarose plug and capillary assays and swarm plate analysis. In addition, the strain was chemotactic to a variety of carbon sources that serve as growth substrates, including glucose, arabinose, mannitol, glycerol, gluconate, acetate, succinate, citrate, malate, lactate and casaminoacids. This is the first report on chemotaxis of a hydrocarbon-degrading bacterium towards a pure alkane, such as hexadecane. The fact that environmental isolates show chemotaxis towards contaminant/s present in the site of isolation suggests that chemotaxis might enhance biodegradation by favouring contact between the degrading microorganism and its substrate. [source] Mouse toxicity of Anabaena flos-aquae from Lake Dianchi, ChinaENVIRONMENTAL TOXICOLOGY, Issue 1 2009Xiaojie Pan Abstract Some species of the genera Anabaena can produce various kinds of cyanotoxins, which may pose risks to environment and human health. Anabaena has frequently been observed in eutrophic freshwater of China in recent years, but its toxicity has been reported only in a few studies. In the present study, the toxicity of an Anabaena flos-aquae strain isolated from Lake Dianchi was investigated. Acute toxicity testing was performed by mouse bioassay using crude extracts from the lyophilized cultures. The mice exposed to crude extracts showed visible symptoms of toxicity and died within 10,24 h of the injection. Serum biochemical parameters were evaluated by the use of commercial diagnostic kits. Significant alterations were found in the serum biochemical parameters: alkaline phosphatase (AKP), ,-glutamyl transpeptidase (,-GT), aspartate amino transferase (AST), alanine amino transferase (ALT), AST/ALT ratio, total protein content, albumin content, albumin/globulin (A/G) ratio, blood urea nitrogen (BUN), serum creatinine (Ssr), and total antioxidative capacity (T-AOC). Histopathological observations were carried out with hematoxylin and eosin (HE) stain under light microscope. Severe lesions were seen in the livers, kidneys, and lungs of the mice injected with crude extracts. The alterations of biochemical parameters were in a dose-dependent manner, and the severities of histological lesions were in the same manner. Based on biochemical and histological studies, this research firstly shows the presence of toxin-producing Anabaena species in Lake Dianchi and the toxic effects of its crude extracts on mammals. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009. [source] Regulation of pyrimidine formation in Pseudomonas oryzihabitansJOURNAL OF BASIC MICROBIOLOGY, Issue 5 2007Thomas P. West Dr. Abstract The regulation of pyrimidine formation in the opportunistic human pathogen Pseudomonas oryzihabitans was investigated at the level of enzyme synthesis and at the level of activity for the pyrimidine biosynthetic pathway enzyme aspartate transcarbamoylase. Although pyrimidine supplementation of succinate-grown P. oryzihabitans cells produced little effect on the de novo pyrimidine biosynthetic pathway enzyme activities, pyrimidine limitation experiments undertaken using an orotidine 5,-monophosphate decarboxylase mutant strain isolated from P. oryzihabitans ATCC 43272 indicated that repression of enzyme synthesis by pyrimidines was occurring. Following pyrimidine limitation of the succinate-grown decarboxylase mutant strain cells, aspartate transcarbamoylase and dihydroorotase activities were found to increase by about 3-fold while dihydroorotate dehydrogenase and orotate phosphoribosyltransferase activities were also observed to increase relative to their activities in the mutant strain cells grown on excess uracil. At the level of enzyme activity, aspartate transcarbamoylase in P. oryzihabitans was strongly inhibited by pyrophosphate, ADP, ATP and GTP in the presence of saturating substrate concentrations. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Yersinia pseudotuberculosis infection in breeding monkeys: detection and analysis of strain diversity by PCRJOURNAL OF MEDICAL PRIMATOLOGY, Issue 3 2002T. Kageyama In the last three decades, several monkeys reared in outdoor/indoor,outdoor breeding colonies and cages of the Primate Research Institute, Kyoto University, died of yersiniosis caused by Yersinia pseudotuberculosis, necessitating introduction of a method to detect the bacteria rapidly and thus allow preventive measures to be undertaken. A rapid nested polymerase chain reaction (PCR) method for identification of Y. pseudotuberculosis in fecal samples and a random amplified polymorphic DNA (RAPD)-PCR approach for distinguishing between bacterial strains were therefore developed. Yersinia pseudotuberculosis isolates from monkey specimens were found to be classifiable into several types. To determine the source of infection, hundreds of fecal samples of wild rats, pigeons, and sparrows were collected from around the breeding colonies and cages, and subjected to PCR analyses. Yersinia pseudotuberculosis was detected in 1.7% of the fecal samples of wild rats. The DNA fingerprints of the bacteria revealed by RAPD-PCR were the same as that of one strain isolated from macaques, suggesting the wild rat to be a possible source of infection. [source] Neutralizing antibody response variation against dengue 3 strainsJOURNAL OF MEDICAL VIROLOGY, Issue 10 2008Mayling Alvarez Abstract To evaluate the neutralizing antibody activity of a human sera panel against seven strains of the homotypic virus. Sera were collected from DENV-3 immune individuals. Two DENV-3 genotypes and strains isolated at different time-points during the 2000 and 2001,2002 Havana epidemics were included. A panel of 20 late convalescent sera collected 16,18 months after acute illness from DF and DHF patients are studied. These individuals were infected during the 2001,2002 Havana DENV-3 epidemic. All but four sera collected from DF cases had a secondary DENV-1/DENV-3 infection. Sera neutralizing antibody titer against the seven DENV-3 strains were determined by plaque reduction neutralization technique. Sera samples were tested simultaneously. Studied sera showed higher levels of neutralizing antibodies to DENV-3 strains of genotype III compared to genotype V. Interesting, higher levels of neutralizing antibodies were detected to DENV-3 strain isolated at the end of the epidemic 2001,2002. An increased tendency of GMT of neutralizing antibodies according to epidemic evolution was observed for the 2001,2002 outbreak. In general, antibody levels in sera collected from DF cases were higher. Differences in the neutralization capacity of immune DENV-3 sera tested against two homologous genotypes including strains of the same genotype are demonstrated. Observed results suggest that virus changed in the course of the epidemic. The implications of this finding in terms of dengue pathogenesis and vaccine development need to be considered. J. Med. Virol. 80:1783,1789, 2008. © 2008 Wiley-Liss, Inc. [source] Genetic characterization of the M RNA segment of a Balkan Crimean-Congo hemorrhagic fever virus strain,JOURNAL OF MEDICAL VIROLOGY, Issue 3 2005Anna Papa Abstract Crimean-Congo hemorrhagic fever (CCHF) virus causes one of the most severe diseases in humans, with a mortality rate of up to 30%. It is transmitted to humans by the bite of hard ticks or by contact with blood or tissues from human patients or infected livestock. Balkan Peninsula is an endemic region of the disease, and sporadic cases or even outbreaks are observed every year. The M RNA segment encodes for the glycoprotein precursor of two surface glycoproteins Gn and Gc. Up to now complete M RNA CCHF virus sequences have been published from strains isolated in Nigeria, China, Pakistan, Tajikistan, and Russia. In the present study, the genetic characterization of the complete nucleotide sequence of the M RNA segment of a Balkan CCHF virus strain, Kosovo/9553/2001, isolated in summer of 2001 from a human fatal case in Kosovo is reported. This is the first published complete M nucleotide sequence of a CCHF virus strain isolated in Balkans. It was found that the Balkan strain is similar to the Russian strain, both strains differing from all other completely sequenced CCHF virus strains by approximately 22% at the nucleotide level forming an independent clade in the phylogenetic tree. J. Med. Virol. 75:466,469, 2005. © 2005 Wiley-Liss, Inc. [source] Evaluation of PetrifilmÔ EC method for enumeration of E. coli from soilLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2010A.D. Samarajeewa Abstract Aims:, To evaluate the suitability of commercially available PetrifilmÔ EC plates for enumeration of Escherichia coli from soil. Methods and Results:, A confirmed E. coli strain isolated from liquid swine manure was inoculated into sterilized sandy clay loam and loam soils at the concentrations of 102, 103, 105 CFU g,1 of soil. The efficiency of recovery on PetrifilmÔ EC plates for soils spiked with E. coli was compared with standard membrane filtration techniques on m-FC basal medium supplemented with 3-bromo-4-chloro-5-indoyl-,- d -glucopyranoside (BCIG) and most probable numbers (MPN) techniques in E. coli medium with 4-methylumbelliferyl-,- d -glucuronide (EC-MUG) broth. PetrifilmÔ EC and m-FC (BCIG) methods were then assessed for the ability to recover E. coli from field soils applied with swine manure. No significant differences (P > 0·05) were observed between PetrifilmÔ EC, m-FC (BCIG) and MPN methods for the recovery of E. coli from spiked samples, irrespective of soil type. However, recovery of E. coli from manure-applied field soil samples showed a significant difference (P < 0·05) between the PetrifilmÔ EC method and the m-FC method in enumerating E. coli possibly as a result of false positives on m-FC. Conclusion:, The PetrifilmÔ EC method is suitable for the enumeration of E. coli from soil with a detection limit of 10 CFU g,1 soil. Significance and Impact of the Study:, The commercially available PetrifilmÔ EC method is comparatively low cost, easy to use method for the enumeration of E. coli from soil without the need for further confirmation tests. [source] A vancomycin-dependent VanA-type Enterococcus faecalis strain isolated in Japan from chicken imported from ChinaLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2005K. Tanimoto Abstract Aims:, The characterization of KC122.1, which is a vancomycin-dependent VRE (Vancomycin-resistant enterococci) (Enterococcus faecalis) and the first case in Japan of a VRE isolate obtained from chicken meat imported from China. Methods and Results:, PCR amplification of vanA, vanS and ddl gene and direct sequencing of the PCR products were performed. KC122.1 was a VanA-type VRE showing high-level vancomycin resistance and low-level teicoplanin resistance, and its vanS gene had three point mutations. The ddl gene of KC122.1 was sequenced and two changes were found at the ninth codon (GCC,GAC) and the stop codon (TAA,CAA). The latter change was also found in the laboratory strain E. faecalis FA2-2. Conclusions:, Three point mutations in vanS resulted in high-level vancomycin resistance and low-level teicoplanin resistance. The change at the ninth codon resulted in the inactivation of the ddl gene and vancomycin-dependent growth. An eight amino acid extension at the C-terminal did not impair the function of the d -Ala : d -Ala ligase. Significance and Impact of the study:, This is the first example of the isolation of VRE from chicken meat imported from China and the first vancomycin-dependent VRE from a nonhuman source. [source] Complete assignment of the NMR spectra of [D -Leu1]-microcystin-LR and analysis of its solution structureMAGNETIC RESONANCE IN CHEMISTRY, Issue 9 2002Jan Schripsema Abstract [D -Leu1]-microcystin-LR is a recently discovered microcystin. We report the isolation of this microcystin analogue from a Microcystis aeruginosa strain isolated from the Lagoa de Iquipari, Rio de Janeiro, Brazil. The 1H and 13C NMR spectra were completely assigned in both MeOH- d4 and DMSO- d6. Further, the solution structure of this compound was investigated with the use of two-dimensional NMR and the amide proton temperature dependence, and was compared with those of its analogs, microcystin-RR and microcystin-LR. Copyright © 2002 John Wiley & Sons, Ltd. [source] Low p38 MAPK and JNK activation in cultured hepatocytes of DRH rats; a strain highly resistant to hepatocarcinogenesisMOLECULAR CARCINOGENESIS, Issue 9 2007Satoshi Honmo Abstract DRH rats are a hepatocarcinogenesis-resistant strain isolated from hepatocarcinogenesis-sensitive Donryu rats, and the liver of DRH shows less histological damage and fewer/smaller neoplastic hepatic lesions by the treatment with hepatocarcinogens. To investigate the mechanism of the resistance, the properties of hepatocytes of DRH and Donryu were compared. In primary culture, DRH hepatocytes exhibited higher proliferation and less apoptosis than Donryu hepatocytes in the presence of EGF and insulin. However, such difference was not correlated to the degree of DNA damage associated with cell culture or cell cycle checkpoint function. Although the mitogen-activated protein kinases [EGF receptor (EGFR) and extracellular signal regulating kinases (ERK1/2)] were activated to the same degree, the stress-activated protein kinases [p38 mitogen-activated protein kinase (p38) and c- jun N-terminal kinase (JNK)] were activated to a lesser degree in the DRH hepatocytes. Treatment with 2-acetylaminofluorene (2-AAF) in vivo also resulted in less JNK and p38 activation in the DRH livers. Furthermore, apoptosis signal-regulating kinase 1 (ASK1) was inhibited by the lysate from the DRH but not by the Donryu hepatocytes. The low activation of the stress-activated protein kinases may be linked to the resistance to cellular stress, which may underlie the hepatocarcinogenesis-resistance in DRH rats. © 2007 Wiley-Liss, Inc. [source] Effect of temperature on growth of the cyanobacterium Aphanizomenon flos-aquae in Lake Biwa and Lake YogoPHYCOLOGICAL RESEARCH, Issue 4 2001Shigeo Tsujimura SUMMARY The water bloom-forming cyanobacterium Aphanizomenon flos-aquae Ralfs ex Bornet et Flahault (Nos-tocales, Cyanophyceae) appeared in Lake Biwa and Lake Yogo in 1999 for the first time. The morphological characteristics were described using natural samples. In contrast to the other water bloom-forming cyanobacteria such as Microcystis and Anabaena in Lake Biwa and Lake Yogo, the small summer population of A. flos-aquae is apt to grow in winter, suggesting the low temperature preference or tolerance of this species. In order to clarify the effect of temperature on the growth, culture experiments were conducted using an axenic strain isolated from Lake Biwa. The strain could grow at above 8°C with an optimum temperature ranging from 23 to 29°C, and survived even at 5°C for at least 25days under low light conditions. Although these results confirmed the ability of the bloom formation during late autumn and winter, it is still unclear why the Aphanizomenon bloom occurred at temperatures of ca 10°C in December and not immediately after the disappearance of Microcystis and/or Anabaena bloom during autumn. [source] Staphylococcus aureus as source of catheter-related bloodstream infection evaluated by PFGE and rep-PCR typing in a Brazilian hospital,APMIS, Issue 11 2008GERALDO SADOYAMA Staphylococci are a common cause of catheter-related bloodstream infection (CR-BSI), and epidemiological typing is an important tool for effective infection control. This study evaluated by PFGE and rep-PCR whether Staphylococcus aureus strains isolated from skin and catheter tips were related to specimens isolated from blood. A prospective observational study, carried out in a clinical surgical ward at a Brazilian hospital between September 2000 and November 2002, investigated non-tunneled central venous catheters from 179 patients. S. aureus isolates were mainly obtained from blood (41.4%), while coagulase-negative staphylococci strains were more often isolated from the skin at the catheter insertion site (49.7%) and from the catheter tip (57.5%). Among the 21 strains isolated from 9 patients at 2 or 3 sites simultaneously, 9 were methicillin-resistant S. aureus (MRSA) and 12 were methicillin-susceptible S. aureus (MSSA). Seven patients harbored the same S. aureus strain isolated from the skin, blood and/or catheter tip cultures. MRSA isolates belonged to one PFGE pattern (type A- subtypes A1, A2 and A3), and to two rep-PCR patterns (a and b). MSSA isolates were distinguished in five PFGE (B to F) and in three rep-PCR (c, d and e) patterns. Both PFGE and rep-PCR methods indicated that the skin at the catheter insertion site was the origin of CR-BSI caused by S. aureus. [source] Identification of gut-associated amylase, cellulase and protease-producing bacteria in three species of Indian major carpsAQUACULTURE RESEARCH, Issue 10 2010Arun Kumar Ray Abstract Isolation and enumeration of amylase, cellulase and protease-producing autochthonous bacteria in the proximal intestine (PI) and distal intestine (DI) of three species of Indian major carps, catla (Catla catla), mrigal (Cirrhinus mrigala) and rohu (Labeo rohita), were investigated using the conventional culture-based technique. Population levels of amylolytic strains were the highest in the PI of catla and the lowest in the DI of rohu. The highest viable count of cellulase and protease-producing bacteria was recorded in the DI and PI of mrigal respectively. Among the bacteria isolated, 10 strains (five from PI and five from DI) were selected as potent enzyme producers according to a quantitative enzyme assay. The chosen strains were further identified by 16S rRNA gene sequence analysis. The five strains isolated from catla showed high similarity to Citrobacter sp. clone W2, Enterobacter sp. JA24, Bacillus coagulans strain TR, uncultured bacterial clone Hel3bc04 and Bacillus cereus strain UST2006-BC004. The four strains isolated from mrigal were most closely related to Bacillus sp. KCd2, uncultured bacterial clone Hel3bd09, B. cereus strain BU040901-020 and Citrobacter freundii strain YRL11, while the strain isolated from rohu probably belonged to Bacillus sp. GV. [source] Mitogenic effect contributes to increased virulence of Streptococcus suis sequence type 7 to cause streptococcal toxic shock-like syndromeCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2008H. Zheng Summary Streptococcus suis serotype 2 sequence type 7 strains emerged in 1996 and caused a streptococcal toxic shock-like syndrome in 1998 and 2005 in China. Evidence indicated that the virulence of S. suis sequence type 7 had increased, but the mechanism was unknown. The sequence type 7 strain SC84, isolated from a patient with streptococcal toxic shock-like syndrome during the Sichuan outbreak, and the sequence type 1 strain 31533, a typical highly pathogenic strain isolated from a diseased pig, were used in comparative studies. In this study we show the mechanisms underlying cytokine production differed between the two types of strains. The S. suis sequence type 7 strain SC84 possesses a stronger capacity to stimulate T cells, naive T cells and peripheral blood mononuclear cell proliferation than does S. suis sequence type 1 strain 31533. The T cell response to both strains was dependent upon the presence of antigen-presenting cells. Histo-incompatible antigen-presenting cells were sufficient to provide the accessory signals to naive T cell stimulated by the two strains, indicating that both sequence type 7 and 1 strains possess mitogens; however, the mitogenic effect was different. Therefore, we propose that the difference in the mitogenic effect of sequence type 7 strain SC84 compared with the sequence type 1 strain 31533 of S. suis may be associated with the clinical, epidemiological and microbiological difference, where the ST 7 strains have a larger mitogenic effect. [source] Phylogenetic analysis of Porphyromonas species isolated from the oral cavity of Australian marsupialsENVIRONMENTAL MICROBIOLOGY, Issue 9 2008Deirdre Mikkelsen Summary Porphyromonas species are frequently isolated from the oral cavity and are associated with periodontal disease in both animals and humans. Black, pigmented Porphyromonas spp. isolated from the gingival margins of selected wild and captive Australian marsupials with varying degrees of periodontal disease (brushtail possums, koalas and macropods) were compared phylogenetically to Porphyromonas strains from non-marsupials (bear, wolf, coyote, cats and dogs) and Porphyromonas gingivalis strains from humans using 16S rRNA gene sequence analysis. The results of the phylogenetic analysis identified three distinct groups of strains. A monophyletic P. gingivalis group (Group 1) contained only strains isolated from humans and a Porphyromonas gulae group (Group 2) was divided into three distinct subclades, each containing both marsupial and non-marsupial strains. Group 3, which contained only marsupial strains, including all six strains isolated from captive koalas, was genetically distinct from P. gulae and may constitute a new Porphyromonas species. [source] The rhizosphere as a reservoir for opportunistic human pathogenic bacteriaENVIRONMENTAL MICROBIOLOGY, Issue 11 2005Gabriele Berg Summary During the last years, the number of human infections caused by opportunistic pathogens has increased dramatically. One natural reservoir of opportunistic pathogens is the rhizosphere, the zone around roots that is influenced by the plant. Due to a high content of nutrients, this habitat is a ,microbial hot-spot', where bacterial abundances including those with strong antagonistic traits are enhanced. Various bacterial genera, including Burkholderia, Enterobacter, Herbaspirillum, Ochrobactrum, Pseudomonas, Ralstonia, Staphylococcus and Stenotrophomonas, contain root-associated strains that can encounter bivalent interactions with both plant and human hosts. Mechanisms responsible for colonization of the rhizosphere and antagonistic activity against plant pathogens are similar to those responsible for colonization of human organs and tissues, and pathogenicity. Multiple resistances against antibiotics are not only found with clinical strains but also with strains isolated from the rhizosphere. High competition, the occurrence of diverse antibiotics in the rhizosphere, and enhanced horizontal gene transfer rates in this microenvironment appear to contribute to the high levels of natural resistances. While opportunistic bacteria from the rhizosphere have some properties in common, each of these emerging pathogens has its own features, which are discussed in detail for Burkholderia, Ochrobactrum and Stenotrophomonas. [source] Ecotype diversity in the marine picoeukaryote Ostreococcus (Chlorophyta, Prasinophyceae)ENVIRONMENTAL MICROBIOLOGY, Issue 6 2005Francisco Rodríguez Summary The importance of the cyanobacteria Prochlorococcus and Synechococcus in marine ecosystems in terms of abundance and primary production can be partially explained by ecotypic differentiation. Despite the dominance of eukaryotes within photosynthetic picoplankton in many areas a similar differentiation has never been evidenced for these organisms. Here we report distinct genetic [rDNA 18S and internal transcribed spacer (ITS) sequencing], karyotypic (pulsed-field gel electrophoresis), phenotypic (pigment composition) and physiological (light-limited growth rates) traits in 12 Ostreococcus strains (Prasinophyceae) isolated from various marine environments and depths, which suggest that the concept of ecotype could also be valid for eukaryotes. Internal transcribed spacer phylogeny grouped together four deep strains isolated between 90 m and 120 m depth from different geographical origins. Three deep strains displayed larger chromosomal bands, different chromosome hybridization patterns, and an additional chlorophyll (chl) c -like pigment. Furthermore, growth rates of deep strains show severe photo-inhibition at high light intensities, while surface strains do not grow at the lowest light intensities. These features strongly suggest distinct adaptation to environmental conditions encountered at surface and the bottom of the oceanic euphotic zone, reminiscent of that described in prokaryotes. [source] Phenotypic and genotypic characterization of encapsulated Escherichia coli isolated from blooms in two Australian lakesENVIRONMENTAL MICROBIOLOGY, Issue 5 2005Michelle L. Power Summary Escherichia coli has long been used as an indicator organism for water quality assessment. Recently there has been an accumulation of evidence that suggests some strains of this organism are able to proliferate in the environment, a characteristic that would detract from its utility as an indicator of faecal pollution. Phenotypic and genotypic characterization of E. coli isolated from blooms in two Australian lakes, separated by a distance of approximately 200 km, identified that the blooms were dominated by three E. coli strains. A major phenotypic similarity among the three bloom strains was the presence of a group 1 capsule. Genetic characterization of a conserved region of the cps gene cluster, which encodes group 1 capsules, identified a high degree of genetic variation within the bloom isolates. This differs from previously described encapsulated E. coli strains which are highly conserved at the cps locus. The phenotypic or genotypic profiles of the bloom strains were not identified in 435 E. coli strains isolated from vertebrates. The occurrence of these encapsulated strains suggests that some E. coli have evolved a free-living lifestyle and do not require a host in order to proliferate. The presence of the same three strains in bloom events in different geographical regions of a temperate climate, and at different times, indicates that free-living E. coli strains are able to persist in these water reservoirs. This study provides further evidence of circumstances where caution is required in using E. coli as an indicator organism for water quality. [source] Genetic diversity of the toxic cyanobacterium Microcystis in Lake MikataENVIRONMENTAL TOXICOLOGY, Issue 3 2005Mitsuhiro Yoshida Abstract The aim of the present study was to clarify the bloom dynamics and community composition of hepatotoxin microcystin-producing and non-microcystin-producing Microcystis genotypes in the environment. In Lake Mikata (Fukui, Japan) from April 2003 to January 2004, seasonal variation in the number of cells with microcystin (mcy) genotypes and the genetic diversity of the total population were investigated using quantitative competitive PCR and a 16S rDNA clone library, respectively. Using competitive PCR, cells with mcyA genotypes were quantified in August and October, and the ratio of the number of these mcyA genotypes to colony-forming Microcystis cells was 0.37 and 2.37, respectively. The 16S rDNA clones obtained could be divided into 12 ribotypes: a,l. Sixty-one Microcystis strains isolated from Lake Mikata during the sampling period were subjected to toxicity tests using HPLC and ELISA, PCR-based detection of the mcyA gene, and sequence analysis of the 16S rDNA. All isolates could be differentiated into 11 ribotypes (a, b, d, f, h, i, and m,q). Ribotypes b, f, i, m, n, and p had at least one strain that was a microcystin producer. In natural communities ribotypes b and f accounted for 85% of the 16S rDNA clones in August, and ribotypes b and i accounted for 24% of the clones in October. Thus, in some bloom stages the presence of microcystin genotypes identified using the 16S rDNA clone library correlated with that of mcy genotypes determined using competitive PCR. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 229,234, 2005. [source] Detection and quantification of microcystins from cyanobacteria strains isolated from reservoirs and ponds in MoroccoENVIRONMENTAL TOXICOLOGY, Issue 1 2002B. Oudra Abstract In Morocco, the occurrence of toxic cyanobacteria blooms is confirmed in some water bodies used for recreational and/or as drinking water reservoirs. According to WHO recommendations, the establishment of a monitoring program for microcystins is a necessity. This paper presents toxicological studies of 19 toxic cyanobacteria strains of Microcystis, Synechocystis, Pseudanabaena, and Oscillatoria. These strains were isolated from various water bodies including natural lakes, reservoirs, and ponds located in central regions of Morocco. The isolation, culture, and biomass production of these strains was made on Z8 or BG13 media under laboratory controlled conditions. The hepatotoxicity of cyanobacterial lyophilized material was confirmed by mouse bioassays. The amount of microcystins produced by each strain was determined by the enzyme-linked immunosorbent assay (ELISA). The detection and identification of microcystin variants was performed by high performance liquid chromatography (HPLC) with photodiode array detection. Almost all strains showed medium to high toxicity, the estimated LD50 i.p mice bioassay ranged between 28 to 350 mg/kg body weight. The concentrations of microcystins varied between 2.16 to 944 ,g/g and 26.8 to 1884 ,g/g dry weight determined by ELISA and HPLC, respectively. The screening of bloom-forming and microcystin producer cyanobacteria strains in these fresh water bodies leads us to propose the need for the establishment of a survey of cyanobacteria and a cyanotoxin-monitoring program. © 2002 by Wiley Periodicals, Inc. Environ Toxicol 17: 32,39, 2002 [source] Selection and identification of bacterial strains with methyl- tert -butyl ether, ethyl- tert -butyl ether, and tert -amyl methyl ether degrading capacitiesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2008Jessica Purswani Abstract Nine bacterial strains isolated from two hydrocarbon-contaminated soils were selected because of their capacity for growth in culture media amended with 200 mg/L of one of the following gasoline oxygenates: Methyl- tert -butyl ether (MTBE), ethyl- tert -butyl ether (ETBE), and tert -amyl methyl ether (TAME). These strains were identified by amplification of their 16S rRNA gene, using fD1 and rD1 primers, and were tested for their capacity to grow and biotransform these oxygenates in both mineral and cometabolic media. The isolates were classified as Bacillus simplex, Bacillus drentensis, Arthrobacter sp., Acinetobacter calcoaceticus, Acinetobacter sp., Gordonia amicalis (two strains), Nocardioides sp., and Rhodococcus ruber. Arthrobacter sp. (strain MG) and A. calcoaceticus (strain M10) consumed 100 (cometabolic medium) and 82 mg/L (mineral medium) of oxygenate TAME in 21 d, respectively, under aerobic conditions. Rhodococcus ruber (strain E10) was observed to use MTBE and ETBE as the sole carbon and energy source, whereas G. amicalis (strain T3) used TAME as the sole carbon and energy source for growth. All the bacterial strains transformed oxygenates better in the presence of an alternative carbon source (ethanol) with the exception of A. calcoaceticus (strain M10). The capacity of the selected strains to remove MTBE, ETBE, and TAME looks promising for application in bioremediation technologies. [source] Microevolutionary analysis of the nematode genus Pristionchus suggests a recent evolution of redundant developmental mechanisms during vulva formationEVOLUTION AND DEVELOPMENT, Issue 4 2001Jagan Srinivasan SUMMARY To identify the mechanisms by which molecular variation is introduced into developmental systems, microevolutionary approaches to evolutionary developmental biology have to be taken. Here, we describe the molecular and developmental characterization of laboratory strains of the nematode genus Pristionchus, which lays a foundation for a microevolutionary analysis of vulva development. We describe 13 laboratory strains of the Pristionchus genus that are derived from natural isolates from around the world. Mating experiments and ITS sequence analysis indicated that these 13 strains represent four different species: the gonochoristic species P. lheritieri and three hermaphroditic species, P. pacificus, P. maupasi, and an as yet undescribed species Pristionchus sp., respectively. P. pacificus is represented by five different strains isolated from California, Washington, Hawaii, Ontario, and Poland. Developmental differences during vulva formation are observed between strains from different species but also between strains of P. pacificus, like the strains from California and Poland. In particular, redundant developmental mechanisms present during vulva formation in P. pacificus var. California are absent in other strains. Amplified restriction fragment length polymorphism (AFLP) analyses of the P. pacificus strains revealed that the American strains are highly polymorphic. In contrast, the developmentally distinct strain from Poland is identical to the Californian strain, suggesting that the developmental differences rely on a small number of changes in developmental control genes rather than the accumulation of changes at multiple loci. [source] Biofilms in chronic bacterial prostatitis (NIH-II) and in prostatic calcificationsFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2010Sandra Mazzoli Abstract The prevalence of inflammatory conditions of the prostate gland is increasing. In Italy, there is a high incidence of prostatitis (13.3%), also accompanied by prostatic calcifications. Cat NIH-II chronic bacterial prostatitis (CBPs) are the most frequent. Their aetiology theoretically involves the whole range of bacterial species that are able to form biofilms and infect prostate cells. The aim of our study was to isolate potential biofilm-producing bacteria from CBP patients, to evaluate their ability to produce in vitro biofilms, and to characterize intraprostatic bacteria and prostatic calcifications using scanning electron microscopy. The 150 clinical bacterial strains isolated from chronic prostatitis NIH-II patients were: 50 Enterococcus faecalis; 50 Staphylococcus spp.; 30 Escherichia coli; 20 gram-negative miscellanea. Quantitative assay of biofilm production and adhesion was performed according to the classic Christensen microwell assay. Isolates were classified as nonproducers, weak, moderate or strong producers. The majority of E. coli, gram-negative bacteria, Staphylococci and Enterococci strains were strong or medium producers: 63,30%, 75,15%, 46,36%, and 58,14%, respectively. Prostatic calcifications consisted of bacteria-like forms similar to the species isolated from biological materials and calcifications of patients. Our study proves, for the first time, that bacterial strains able to produce biofilms consistently are present in CBP. Additionally, prostatic calcifications are biofilm-related. [source] Leptospira interrogans is recognized through DC-SIGN and induces maturation and cytokine production by human dendritic cellsFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2008Narintorn Gaudart Abstract Leptospirosis is a global zoonotic disease, caused by pathogenic Leptospira species including Leptospira interrogans, that causes public health and livestock problems. Pathogenesis, immune response and cellular receptors for Leptospira are not well understood. Interaction of dendritic cells (DCs) with L. interrogans serovar Autumnalis L-643 and BL-6 isolated from leptospirosis patients, and both virulent and avirulent serovar Pyrogenes 2317 strains isolated from animal were investigated. Carbohydrate analysis using lectins showed that all of these leptospires contained high mannose components as a common backbone and DC-SIGN was involved in leptospires' attachment. Interaction of the L. interrogans strains with DCs induced maturation, but had different effects on IL-10, IL-12p70 and tumor necrosis factor (TNF)-, production. Both virulent and avirulent Pyrogenes 2317 and Autumnalis BL-6 but not L-643 strains induced IL-12p70 and TNF-, production, but minimal IL-10 secretion. These data demonstrated that L. interrogans binds DC-SIGN and induces DCs maturation and cytokine production, which should provide new insights into cellular immune processes during leptospirosis. [source] Effect of suramin on the human pathogen Candida albicans: implications on the fungal development and virulenceFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2007Lys Adriana Braga-Silva Abstract Candida albicans is an opportunistic pathogen that is of growing medical importance because it causes superficial, mucosal and systemic infections in susceptible individuals. Here, the effect of suramin, a polysulfonated naphthylurea derivative, on C. albicans development and virulence was evaluated. Firstly, it was demonstrated that suramin (500 ,M) arrested its growth, showing a fungicidal action dependent on cell number. Suramin treatment caused profound changes in the yeast ultrastructure as shown by transmission electron microscopy. The more important changes were the enlargement of the fungi cytoplasmic vacuoles, the appearance of yeasts with an empty cytoplasm resembling ghost cells and a reduction in cell wall thickness. Suramin also blocked the transformation of yeast cells to the germ-tube and the interaction between C. albicans and epithelial cells. In order to ascertain that the action of suramin on C. albicans growth is a general feature instead of being strain-specific, the effects of suramin on 14 oral clinical strains isolated from healthy children and HIV-positive infants were analyzed. Interestingly, the strains of C. albicans isolated from HIV-positive patients were more resistant to suramin than strains isolated from healthy patients. Altogether, the results produced here show that suramin interfered with essential fungal processes, such as growth, differentiation and interaction with host cells. [source] | ||||||||||||||||||||||||||||||||||||||||