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Type Strain (type + strain)
Kinds of Type Strain Selected AbstractsA differential medium for lactic acid-producing bacteria in a mixed cultureLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2008H.M. Lee Abstract Aims:, Modified deMan-Rogosa Sharpe agar containing bromophenol blue (mMRS-BPB) was tested as a medium for counting and differentiation of each lactic acid-producing bacterium (LAB), especially in a mixed culture. Methods and Results:, Type strains of 10 LAB species (Lactobacillus acidophilus, L. brevis, L. bulgaricus, L. gasseri, L. paracasei, L. plantarum, L. reuteri, Weissella confusa, Bifidobacterium bifidum and B. infantis) and five commercial yogurts were inoculated on plate count agar with bromocresol purple, mMRS, and mMRS-BPB. Each type strain showed more clearly formed colonies on the three media under anaerobic conditions than under aerobic conditions. Especially each type strain produced colonies with specific characteristics of each species on mMRS-BPB. Commercial yogurts produced the largest number of colonies with various shapes and colours on mMRS-BPB. Conclusions:, Modified deMan-Rogosa Sharpe agar containing bromophenol blue under anaerobic conditions is appropriate for counting and differentiating each LAB in a mixed culture. Significance and Impact of the Study:, Modified deMan-Rogosa Sharpe agar containing bromophenol blue will be useful in isolation and enumeration of each LAB from fermented foods as well as intestinal microflora. [source] Isolation and properties of methanesulfonate-degrading Afipia felis from Antarctica and comparison with other strains of A. felisENVIRONMENTAL MICROBIOLOGY, Issue 1 2005S. Azra Moosvi Summary Three novel strains of methylotrophic Afipia felis were isolated from several locations on Signy Island, Antarctica, and a fourth from estuary sediment from the River Douro, Portugal. They were identified as strains of the ,-2 proteobacterium A. felis by 16S rRNA gene sequence, analysis., Two, strains, tested, were, shown to contain the fdxA gene, diagnostic for A. felis. All strains grew with methanesulfonate (and two strains with dimethylsulfone) as sole carbon substrate. Growth on methanesulfonate required methanesulfonate monooxygenase (MSAMO), using NADH as the reductant and stimulated by reduced flavin nucleotides and Fe(II). Polymerase chain reaction amplification of DNA from an Antarctic strain showed a typical msmA gene for the ,-hydroxylase of MSAMO, and both Antarctic and Portuguese strains contained mxaF, the methanol dehydrogenase large subunit gene. This is the first report of methanesulfonate-degrading bacteria from the Antarctic and of methylotrophy in Afipia, and the first description of any bacterium able to use both methanesulfonate and dimethylsulfone. In contrast, the type strain of A. felis DSM 7326T was not methylotrophic, but grew in defined mineral medium with a wide range of single simple organic substrates. Free-living Afipia strains occurring widely in the natural environment may be significant as methylotrophs, degrading C1 -sulfur compounds, including the recalcitrant organosulfur compound methanesulfonate. [source] The structure of a local population of phytopathogenic Pseudomonas brassicacearum from agricultural soil indicates development under purifying selection pressureENVIRONMENTAL MICROBIOLOGY, Issue 3 2001Johannes Sikorski Among the isolates of a bacterial community from a soil sample taken from an agricultural plot in northern Germany, a population consisting of 119 strains was obtained that was identified by 16S rDNA sequencing and genomic fingerprinting as belonging to the recently described species Pseudomonas brassicacearum. Analysis of the population structure by allozyme electrophoresis (11 loci) and random amplified polymorphic DNA,polymerase chain reaction (RAPD,PCR; four primers) showed higher resolution with the latter method. Both methods indicated the presence of three lineages, one of which dominated strongly. Stochastic tests derived from the neutral theory of evolution (including Slatkin's exact test, Watterson's homozygosity test and the Tajima test) indicated that the population had developed under strong purifying selection pressure. The presence of strains clearly divergent from the majority of the population can be explained by in situ evolution or by influx of strains as a result of migration or both. Phytopathogenicity of a P. brassicacearum strain determined with tomato plants reached the level obtained with the type strain of the known pathogen Pseudomonas corrugata. The results show that a selective sweep was identified in a local population. Previously, a local selective sweep had not been seen in several populations of different bacterial species from a variety of environmental habitats. [source] First laboratory confirmation of Xylophilus ampelinus in Slovenia,EPPO BULLETIN, Issue 1 2005T. Dreo Bacterial blight of grapevine is caused by a slow-growing bacterium Xylophilus ampelinus. It has been suspected to occur in Slovenia on the basis of visual observation of characteristic symptoms in the 1960s. In the present study, symptoms were recorded in an infected vineyard during three consecutive years (2002/2004). Samples from this vineyard were tested by nested-PCR and isolation of bacteria on media was attempted. In the first year, angular lesions on leaves were highly expressed and an isolate morphologically similar to X. ampelinus was obtained from one sample. It was purified and identified as X. ampelinus using biochemical and nutritional tests, fatty acid analysis, immuno-fluorescence, nested PCR and partial sequencing of the 16S rRNA gene. The 16S rDNA sequence showed 99,100% homology to known sequences of X. ampelinus strains, including the type strain. Pathogenicity of the isolate was confirmed in tissue-cultured and potted grapevine plants. In the following two years, symptoms of bacterial blight were only faintly expressed. Using isolation on media and nested-PCR, 23 and 17 extracts prepared from 10 and 8 grapevines, respectively, were analysed. In 2003, no positive sample was found, but X. ampelinus was again isolated and identified by colony morphology and nested-PCR in 2004. [source] Calcium and magnesium competitively influence the growth of a PMR1 deficient Saccharomyces cerevisiae strainFEMS MICROBIOLOGY LETTERS, Issue 2 2005Réka Szigeti Abstract PMR1, the Ca2+/Mn2+ ATPase of the secretory pathway in Saccharomyces cerevisiae was the first member of the secretory pathway Ca2+ ATPases (SPCA) to be characterized. In the past few years, pmr1, yeast have received more attention due to the recognition that the human homologue of this protein, hSPCA1 is defective in chronic benign pemphigus or Hailey,Hailey disease (HHD). Recent publications have described pmr1, S. cerevisiae as a useful model organism for studying the molecular pathology of HHD. Some observations indicated that the high Ca2+ sensitive phenotype of PMR1 defective yeast strains may be the most relevant in this respect. Here we show that the total cellular calcium response of a pmr1, S. cerevisiae upon extracellular Ca2+ challenge is decreased compared to the wild type strain similarly as observed in keratinocytes. Additionally, the novel magnesium sensitivity of PMR1 defective yeast is revealed, which appears to be a result of competition for uptake between Ca2+ and Mg2+ at the plasma membrane level. Our findings indicate that extracellular Ca2+ and Mg2+ competitively influence the intracellular Ca2+ homeostasis of S. cerevisiae. These observations may further our understanding of HHD. [source] Distribution of ecto 5,-nucleotidase on Mycoplasma species associated with arthritisFEMS MICROBIOLOGY LETTERS, Issue 1 2000Sheena Johnson Abstract The enzyme ecto 5,-nucleotidase (5,N) was found to be active on 8/14 strains of Mycoplasma fermentans, Km (±S.D.) 3.8±2.8 ,M 5,-AMP, and on the type strain of Mycoplasma pulmonis, Km 0.63 ,M 5,-AMP. The six M. fermentans strains lacking 5,N activity were related by restriction fragment length polymorphism typing. At pH 8.5, the type strains of Mycoplasma arthritidis, Mycoplasma buccale and Ureaplasma urealyticum showed a relatively non-specific phosphatase activity against 5,-AMP but no activity was shown by the type strains of Mycoplasma genitalium, Mycoplasma hominis, Mycoplasma orale, Mycoplasma penetrans, Mycoplasma pneumoniae and Mycoplasma salivarium at this pH. M. fermentans has been reported from rheumatoid joints, which show a raised 5,N activity on their synovial cells and in their fluid which may be associated directly or indirectly with the mycoplasma. [source] Genetic variations among Mycoplasma bovis strains isolated from Danish cattleFEMS MICROBIOLOGY LETTERS, Issue 1 2000Lughano J.M. Kusiluka Abstract The genetic heterogeneity of Mycoplasma bovis strains isolated in Denmark over a 17-year period was investigated. Forty-two field strains isolated from different geographic locations and specimens, including strains from 21 herds involved in two outbreaks of M. bovis -induced mastitis, and the type strain of M. bovis (PG45T) were assayed for variations in the BglII and MfeI restriction sites in the chromosomal DNA by using the amplified fragment length polymorphism (AFLP) fingerprinting technique. The obtained genomic fingerprints consisted of 62,68 AFLP fragments in the size range of 50,500 bp. Among the analyzed strains, 18 different AFLP profiles were detected. The similarity between individual fingerprints, calculated by Dice similarity coefficient, ranged from 0.9 to 1.0. Twenty-five strains, including 23 which were isolated during two outbreaks of M. bovis -induced mastitis which occurred 2 years apart, showed indistinguishable AFLP patterns. More genetic diversity was observed among the recent strains. The similarity of the genotypes of the field strains to that of the M. bovis type strain (PG45T) was 97.7%. The results of this study have demonstrated a remarkable genomic homogeneity of Danish strains of M. bovis that were probably epidemiologically related and which have remained stable for a considerable length of time. Furthermore, this study has demonstrated that AFLP can be used for genomic fingerprinting and discrimination of M. bovis strains. [source] A tool kit for molecular genetics of Kluyveromyces lactis comprising a congenic strain series and a set of versatile vectorsFEMS YEAST RESEARCH, Issue 3 2010Jürgen J. Heinisch Abstract A set of different marker deletions starting with a ura3 derivative of the Kluyveromyces lactis type strain CBS2359 was constructed. After a first cross to obtain a strain with the opposite mating type that also carried a leu2 allele, continuous back-crosses were used to obtain a congenic strain series with different marker combinations, including deletions in KlHIS3, KlADE2 and KlLAC4. Enzymes involved in carbohydrate metabolism were shown to behave very similarly to the original type strain and other K. lactis strains investigated previously. Moreover, a vector series of Saccharomyces cerevisiae genes flanked by loxP sites was constructed to be used as heterologous deletion cassettes in K. lactis, together with two plasmids for expression of Cre-recombinase for marker regeneration. To increase the frequency of homologous recombination, the Klku80 deletion was also introduced into the congenic strain series. A PCR-based method for determination of mating type is provided. [source] Candida carvajalis sp. nov., an ascomycetous yeast species from the Ecuadorian Amazon jungleFEMS YEAST RESEARCH, Issue 5 2009Stephen A. James Abstract In the course of a yeast biodiversity survey of different ecological habitats found in Ecuador, two yeast strains (CLQCA 20-011T and CLQCA20-014) were isolated from samples of rotten wood and fallen leaf debris collected at separate sites in the central region of the Ecuadorian Amazonia. These strains were found to represent a novel yeast species based on the sequences of their D1/D2 domain of the large-subunit (LSU) rRNA gene and their physiological characteristics. Phylogenetic analysis based on LSU D1/D2 sequences revealed this novel species to be most closely related to Candida asparagi, Candida fructus, Candida musae and two as yet undescribed Candida species, with the six yeast taxa collectively forming a distinct species group within the Clavispora clade. The species name of Candida carvajalis sp. nov. is proposed to accommodate these strains, with CLQCA 20-011T (NCYC 3509T, CBS 11361T) designated as the type strain. [source] Dynamics of in vitro acquisition of resistance by Candida parapsilosis to different azolesFEMS YEAST RESEARCH, Issue 4 2009Ana Teresa Pinto e Silva Abstract Candida parapsilosis is a common isolate from clinical fungal infectious episodes. Resistance of C. parapsilosis to azoles has been increasingly reported. To analyse the development of resistance in C. parapsilosis, four azole-susceptible clinical strains and one American Type Culture Collection type strain were cultured in the presence of fluconazole, voriconazole and posaconazole at different concentrations. The isolates developed variable degrees of azole resistance according to the antifungal used. Fluconazole was the fastest inducer while posaconazole was the slowest. Fluconazole and voriconazole induced resistance to themselves and each other, but not to posaconazole. Posaconazole induced resistance to all azoles. Developed resistance was stable; it could be confirmed after 30 days of subculture in drug-free medium. Azole-resistant isolates revealed a homogeneous population structure; the role of azole transporter efflux pumps was minor after evaluation by microdilution and cytometric assays with efflux pump blockers (verapamil, ibuprofen and carbonyl cyanide 3-chloro-phenylhydrazone). We conclude that the rapid development of azole resistance occurs by a mechanism that might involve mutation of genes responsible for ergosterol biosynthesis pathway, stressed by exposure to antifungals. [source] Multilocus sequence typing confirms synonymy but highlights differences between Candida albicans and Candida stellatoideaFEMS YEAST RESEARCH, Issue 5 2008Mette D. Jacobsen Abstract We used multi-locus sequence typing (MLST) to investigate 35 yeast isolates representing the two genome-sequenced strains plus the type strain of Candida albicans, four isolates originally identified as Candida stellatoidea type I and 28 representing type strains of other species now regarded as synonymous with C. albicans. DNA from all 32 C. albicans synonyms readily formed PCR products with the C. albicans MLST primer sets. Their sequences placed all of them within the existing C. albicans clade structure, represented by 1516 isolates. One isolate, originally received as Mycotorula sinensis, was resistant to flucytosine, but no other unusual susceptibilities were found to polyene, azole or echinocandin antifungal agents. The four isolates of C. stellatoidea type I coclustered with two other sucrose-negative isolates, originally identified as examples of Candida africana, in a group of strains highly distinct from the majority of C. albicans. Our results not only confirm the synonymity of all the isolates with C. albicans but also confirm an obvious genotypic difference in the case of C. stellatoidea type I. [source] RESEARCH ARTICLE: Farysizyma gen. nov., an anamorphic genus in the Ustilaginales to accommodate three novel epiphytic basidiomycetous yeast species from America, Europe and AsiaFEMS YEAST RESEARCH, Issue 3 2008Joăo Inácio Abstract Among many isolates that resulted from four independent surveys of yeasts associated with plants in Brazil, the USA, Portugal and Taiwan, we have characterized eighteen basidiomycetous strains, two of which were conspecific with the type strain of Rhodotorula acheniorum, whereas the remaining sixteen isolates appeared not to correspond to any previously described species. Microsatellite-PCR fingerprinting with primers M13 and (GTG)5 confirmed that the latter strains formed three genetically distinct groups. Each group was considered to represent a distinct species based on nucleotide sequences of the D1/D2 domains of the 26S rRNA gene and the internal transcribed spacer (ITS) region. Phylogenetic analyses of sequence data placed the putative novel species in a clade with R. acheniorum and the dimorphic smut fungus Farysia chardoniana. A novel anamorphic genus, Farysizyma, is created to accommodate the three undescribed species, which were named Farysizyma itapuensis, Farysizyma setubalensis and Farysizyma taiwaniana. A new combination, Farysizyma acheniorum, is proposed for R. acheniorum, which may represent the yeast-phase anamorph of Farysia thuemenii. [source] Tools for the genetic manipulation of Zygosaccharomyces rouxiiFEMS YEAST RESEARCH, Issue 8 2007Lenka Pribylova Abstract A set of tools for the genetic manipulation of the osmotolerant yeast Zygosaccharomyces rouxii was developed. Auxotrophic mutants (ura3 leu2, ura3 ade2, ura3 leu2 ade2) derived from the CBS 732 type strain were prepared. Centromeric and episomal Z. rouxii/Escherichia coli shuttle plasmids with different marker genes (ScURA3, ZrLEU2, ZrADE2) and with multiple cloning sites were constructed, together with a plasmid enabling green fluorescent protein-tagging. A system for repeatable targeted gene deletion in Z. rouxii was established, involving first the integration of a PCR-generated loxP,kanMX,loxP cassette and second the removal of kanMX from the genome using a Z. rouxii plasmid harbouring cre recombinase. [source] Pseudozyma jejuensis sp. nov., a novel cutinolytic ustilaginomycetous yeast species that is able to degrade plastic wasteFEMS YEAST RESEARCH, Issue 6 2007Hyuk-Seong Seo Abstract An ustilaginomycetous anamorphic yeast, isolated from orange leaves on Jeju island in South Korea, represents a novel Pseudozyma species according to morphologic and physiologic findings and molecular taxonomic analysis using the D1/D2 domains of the large subunit (26S) rRNA gene and the internally transcribed spacer (ITS) 1+2 regions. The name Pseudozyma jejuensis sp. nov. is proposed for this novel species, with OL71T (=KCTC 17482T=CBS 10454T) as type strain. In the present study, we have also demonstrated that Pseudozyma jejuensis OL71 is capable of producing cutinase and degrading polycaprolactone. These results suggest that Pseudozyma jejuensis or its cutinase may be useful for the biological degradation of plastic waste. [source] Identification of direct and indirect targets of the Gln3 and Gat1 activators by transcriptional profiling in response to nitrogen availability in the short and long termFEMS YEAST RESEARCH, Issue 5 2006Bart Scherens Abstract Nitrogen catabolite repression (NCR) consists in the specific inhibition of transcriptional activation of genes encoding the permeases and catabolic enzymes needed to degrade poor nitrogen sources. Under nitrogen limitation or rapamycin treatment, NCR genes are activated by Gln3 or Gat1, or by both factors. To compare the sets of genes responding to rapamycin or to nitrogen limitation, we used DNA microarrays to establishing the expression profiles of a wild type strain, and of a double gln3,,gat1, strain, grown on glutamine, after addition of rapamycin, on proline, or after a shift from glutamine to proline. Analysis of microarray data revealed 392 genes whose expression was dependent on the nitrogen source quality. 91 genes were activated in a GATA factor-dependent manner in all growth conditions, suggesting a direct role of Gln3 and Gat1 in their expression. Other genes were only transiently up-regulated (stress-responsive genes) or down-regulated (genes encoding ribosomal proteins and translational factors) upon nitrogen limitation, and this regulation was delayed in a gln3,,gat1, strain. Repression of amino acid and nucleotide biosynthetic genes after a nitrogen shift did not depend on Gcn4. Several transporter genes were repressed as a consequence of enhanced levels of NCR-responsive permeases present at the plasma membrane. [source] Rhodotorula pinicola sp. nov., a basidiomycetous yeast species isolated from xylem of pine twigsFEMS YEAST RESEARCH, Issue 2 2002Jian-Hua Zhao Abstract Three pink-colored yeast strains 3-1-3, 10-3-3 and 19-3-3 were isolated from xylem of surface-sterilized twigs of Pinus tabulaeformis collected from Dongling Mountain, Beijing, in different seasons. These strains were identified as Rhodotorula minuta (Saito) F.C. Harrison by conventional taxonomic characterization. However, molecular phylogenetic analysis based on internal transcribed spacer region (including 5.8S rDNA) and large-subunit rDNA D1/D2 domain sequences indicated that they represent a novel basidiomycetous yeast species, for which Rhodotorula pinicola is proposed (type strain: AS 2.2193T=CBS 9130T). The new species was most closely related to Rhodotorula laryngis Reiersöl in the R. minuta complex. [source] Evidence for multiple interspecific hybridization in Saccharomyces sensu stricto speciesFEMS YEAST RESEARCH, Issue 4 2002Miguel de Barros Lopes Abstract Fluorescent amplified fragment length polymorphism analysis demonstrates a high level of gene exchange between Saccharomyces sensu stricto species, with some strains having undergone multiple interspecific hybridization events with subsequent changes in genome complexity. Two lager strains were shown to be hybrids between Saccharomyces cerevisiae and the alloploid species Saccharomyces pastorianus. The genome structure of CBS 380T, the type strain of Saccharomyces bayanus, is also consistent with S. pastorianus gene transfer. The results indicate that the cider yeast, CID1, possesses nuclear DNA from three separate species. Mating experiments show that there are no barriers to interspecific conjugation of haploid cells. Furthermore, the allopolyploid strains were able to undergo further hybridizations with other Saccharomyces sensu stricto yeasts. These results demonstrate that introgression between the Saccharomyces sensu stricto species is likely. [source] Functional, genetic and chemical characterization of biosurfactants produced by plant growth-promoting Pseudomonas putida 267JOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2009Marco Kruijt Abstract Aims:, Plant growth-promoting Pseudomonas putida strain 267, originally isolated from the rhizosphere of black pepper, produces biosurfactants that cause lysis of zoospores of the oomycete pathogen Phytophthora capsici. The biosurfactants were characterized, the biosynthesis gene(s) partially identified, and their role in control of Phytophthora damping-off of cucumber evaluated. Methods and Results:, The biosurfactants were shown to lyse zoospores of Phy. capsici and inhibit growth of the fungal pathogens Botrytis cinerea and Rhizoctonia solani. In vitro assays further showed that the biosurfactants of strain 267 are essential in swarming motility and biofilm formation. In spite of the zoosporicidal activity, the biosurfactants did not play a significant role in control of Phytophthora damping-off of cucumber, since both wild type strain 267 and its biosurfactant-deficient mutant were equally effective, and addition of the biosurfactants did not provide control. Genetic characterization revealed that surfactant biosynthesis in strain 267 is governed by homologues of PsoA and PsoB, two nonribosomal peptide synthetases involved in production of the cyclic lipopeptides (CLPs) putisolvin I and II. The structural relatedness of the biosurfactants of strain 267 to putisolvins I and II was supported by LC-MS and MS-MS analyses. Conclusions:, The biosurfactants produced by Ps. putida 267 were identified as putisolvin-like CLPs; they are essential in swarming motility and biofilm formation, and have zoosporicidal and antifungal activities. Strain 267 provides excellent biocontrol activity against Phytophthora damping-off of cucumber, but the lipopeptide surfactants are not involved in disease suppression. Significance and Impact of the Study:,Pseudomonas putida 267 suppresses Phy. capsici damping-off of cucumber and provides a potential supplementary strategy to control this economically important oomycete pathogen. The putisolvin-like biosurfactants exhibit zoosporicidal and antifungal activities, yet they do not contribute to biocontrol of Phy. capsici and colonization of cucumber roots by Ps. putida 267. These results suggest that Ps. putida 267 employs other, yet uncharacterized, mechanisms to suppress Phy. capsici. [source] New variants of polar glycopeptidolipids detected in Mycobacterium simiae, including ,habana' strains, as evidenced by electrospray ionization-ion trap-mass spectrometryJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2008L. Mederos Abstract Aims:, To determine the composition of polar glycopeptidolipids (pGPLs) of Mycobacterium simiae and, particularly, those of ,habana' strains, in a search for specific markers given the immunogenic potential of ,habana' TMC 5135 in experimental tuberculosis. Methods and Results:, pGPLs were determined in free lipid extracts using electrospray ionization-ion trap-mass spectrometry (ESI-IT-MS), working in both negative- and positive-ion mode. In the case of TMC 5135, the presence of the previously characterized GPL-II (containing 2,4-di-O-CH3 glucuronic acid as distal sugar in the oligosaccharide antigenic moiety) and GPL-III (containing 4-O-CH3 glucuronic acid as distal sugar) was confirmed using MS/MS and MS/MS/MS approaches. Interestingly, some ,habana' strains presented variants of GPL-II, designated GPL-II,-A and GPL-II,-B. A di-O-CH3 -deoxy-hexose (tentatively, 2,3-di-O-CH3 -fucose) was identified as the penultimate sugar in the oligosaccharide moiety of GPL-II,-A, whereas in GPL-II,-B the penultimate sugar was fucose (tentative identification). On the contrary, the distal sugar of the oligosaccharide chain of pGPLs of Myco. simiae ATCC 25275T was identified as tri-O-CH3 -glucuronic acid (designated GPL-simT -I, with two variants: GPL-simT -I-A and GPL-simT -I-B), O-CH3 -glucuronic acid (designated GPL-simT -II) and di-O-CH3 -glucuronic acid (GPL-II,-A and GPL-II,-B). The penultimate sugar of the oligosaccharide chain of GPL-simT -I-A and GPL-simT -II was identified as di-O-CH3 -deoxy-hexose (tentatively, 2,3-di-O-CH3 fucose), and that of GPL-simT -I-B as deoxy-hexose (tentatively, fucose). In all strains studied, each [M-H], and [M+Na]+ ion was revealed as a mixture of homologous compounds varying in the number of ,O-CH3 groups present in the oligosaccharide moiety and in the length of the fatty acyl linked to the peptide. Conclusions:, The present work indicates that, within a similar general pattern of pGPLs, different strains of Myco. simiae present some variations, so that new compounds (GPL-II,-A, GPL-II,-B, GPL-simT -I-A, GPL-simT -I-B and GPL-simT -II) were defined. Noteworthy was the fact that the ,habana' strains clearly differed from the type strain of Myco. simiae. Significance and Impact of the Study:, The data obtained can be used in the delineation of the ,habana' group of Myco. simiae, including the quality control of the immunogenic strain ,habana' TMC 5135. [source] Tolerance to challenges miming gastrointestinal transit by spores and vegetative cells of Bacillus clausiiJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2006G. Cenci Abstract Aims:, To study Bacillus clausii from a pharmaceutical product (Enterogermina O/C, N/R, SIN, T) and reference strains (B. clausii and Bacillus subtilis) for eco-physiological aspects regarding the gut environment. Methods and Results:, Spores and vegetative cells were challenged in vitro miming the injury of gastrointestinal transit: pH variations, exposure to conjugated and free bile salts, microaerophilic and anaerobic growth. No relevant differences were found studying the growth at pH 8 and 10, whereas at pH 7 the yields obtained for O/C and SIN were higher than those obtained for N/R and T strains. The spores were able to germinate and grow in the presence of conjugated bile salts (up to 1%, w/v) or free bile salts (0·2%) and also exhibited tolerance for the combined acid-bile challenge. As evidenced by lag-time, growth rate and cell yield the tolerance of Enterogermina isolates for conjugated salts was comparable with that of B. clausii type strain (DSM 8716T), and resulted higher than that observed for B. subtilis (ATCC 6051T). All the considered B. clausii strains demonstrated microaerophilic growth, but only some grew anaerobically in a nitrate medium. Conclusions:, The ability of B. clausii spores to germinate after an acid challenge and grow as vegetative cells both in the presence of bile and under limited oxygen availability is consistent with the beneficial health effects evidenced for spore-forming probiotics in recent clinical studies. Significance and Impact of the Study:, The experimental evidence from this study emphasizes some functional properties of B. clausii strains regarding their use as probiotics. [source] Identification of Escherichia coli O172 O-antigen gene cluster and development of a serogroup-specific PCR assayJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2004H. Guo Abstract Aim:, To characterize the locus for O-antigen biosynthesis from Escherichia coli O172 type strain and to develop a rapid, specific and sensitive PCR-based method for identification and detection of E. coli O172. Methods and Results:, DNA of O-antigen gene cluster of E. coli O172 was amplified by long-range PCR method using primers based on housekeeping genes galF and gnd Shot gun bank was constructed and high quality sequencing was performed. The putative genes for synthesis of UDP-FucNAc, O-unit flippase, O-antigen polymerase and glycosyltransferases were assigned by the homology search. The evolutionary relationship between O-antigen gene clusters of E. coli O172 and E. coli O26 is shown by sequence comparison. Genes specific to E. coli O172 strains were identified by PCR assays using primers based on genes for O-unit flippase, O-antigen polymerase and glycosyltransferases. The specificity of PCR assays was tested using all E. coli and Shigella O-antigen type strains, as well as 24 clinical E. coli isolates. The sensitivity of PCR assays was determined, and the detection limits were 1 pg ,l,1 chromosomal DNA, 0·2 CFU g,1 pork and 0·2 CFU ml,1 water. The total time required from beginning to end of the procedure was within 16 h. Conclusion:, The O-antigen gene cluster of E. coli O172 was identified and PCR assays based on O-antigen specific genes showed high specificity and sensitivity. Significance and Impact of the Study:, An O-antigen gene cluster was identified by sequencing. The specific genes were determined for E. coli O172. The sensitivity of O-antigen specific PCR assay was tested. Although Shiga toxin-producing O172 strains were not yet isolated from clinical specimens, they may emerge as pathogens. [source] Effect of galactose and glucose on the exopolysaccharide production and the activities of biosynthetic enzymes in Lactobacillus casei CRL 87JOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2001F. Mozzi Aims: The objective of this work was to study the influence of the sugar source on exopolysaccharide (EPS) production and the activities of the enzymes involved in the synthesis of sugar nucleotides in Lactobacillus casei CRL 87. The relationship between these enzymes and EPS formation was determined. Methods and Results: The concentration of EPS was estimated by the phenol/sulphuric acid method while the chemical composition of purified EPS was investigated using gas-liquid chromatography. Biosynthetic enzyme activities were determined spectrophotometrically by measuring the formation or disappearance of NAD(P)H at 340 nm. Polysaccharide production by Lb. casei CRL 87 was 1·7 times greater on galactose than on glucose. The isolated polymer was composed of rhamnose, glucose and galactose. The activities of uridine-diphosphate (UDP)-glucose-pyrophosphorylase, thymidine-diphosphate (dTDP)-glucose-pyrophosphorylase and the dTDP-rhamnose-synthetic enzyme system were higher in galactose-grown than in glucose-grown cells. When an EPS, mutant strain was used, galactokinase activity was not detected on galactose, this sugar not being available for the formation of sugar nucleotides for further EPS production. dTDP-glucose-pyrophosphorylase and dTDP-rhamnose-synthetic enzyme system activities were lower than the values found for the wild type strain. Conclusions: The carbon source present in the culture medium affects EPS production by Lb. casei CRL 87. The greater polymer synthesis by galactose-grown cells is correlated with the higher UDP-glucose-pyrophosphorylase, dTDP-glucose-pyrophosphorylase and dTDP-rhamnose-synthetic enzyme system activities. Initial sugar metabolism is also an important step for the synthesis of EPS precursors by this strain. Significance and Impact of the Study: Knowledge of the effect of the sugar source on EPS production and the activities of biosynthetic enzymes provides information about the mechanisms of regulation of the synthesis of EPS which can contribute to improving polymer production. [source] Cover Picture: J. Basic Microbiol.JOURNAL OF BASIC MICROBIOLOGY, Issue 2 20092/200 Morphological diversity among Anabaena isolates from major agro-ecologies of India, depicting the heterogeneity in shape, size and colour of cells and trichomes. Shown are Anabaena type strain, coiled filaments (A. circinalis), pointed end cell (A. spiroides), double heterocysts (A. iyengarii), heterocysts (A. aphanizomenoides), large, oval and boat shaped akinetes (A. flos-aquae, A. anomala, A. naviculoides), in-situ germination of akinetes (A. sphaerica) and a series of akinetes (A. variabilis var. ellipsospora). Scale bar = 40 ,m (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Genetic analysis of aquabirnaviruses isolated from wild fish reveals occurrence of natural reassortment of infectious pancreatic necrosis virusJOURNAL OF FISH DISEASES, Issue 7 2009I Romero-Brey Abstract In this study, we report the sequencing of the whole genome [including the 5, and 3, non-coding regions (NCR) of both segments A and B] of seven birnavirus strains isolated from wild fish from the Flemish Cap (FC) fishery at Newfoundland, Canada. From analysis and comparison of the sequences, most of the FC isolates clustered with the North American reference strains West Buxton (WB), Dry Mill and Jasper. One strain was included in the same genotype as the European strain Ab. In addition, at least in one case cohabitation of both type strains in an individual fish was demonstrated. These results clearly suggest the acquisition of the viruses from two different sources. The prevalence of the American type is easily explained by the close proximity of this fishing bank to the American coast whereas, although surprising, the presence of the European type strain could be because of migration of fish from European waters. In one strain, segment A and B sequences were typed differently (WB and Ab, respectively). These findings indicate natural reassortment between two strains of aquabirnaviruses in a host. [source] Phenotypic, serological and genetic characterization of Flavobacterium psychrophilum strains isolated from salmonids in ChileJOURNAL OF FISH DISEASES, Issue 4 2009S Valdebenito Abstract Characterization of 20 Flavobacterium psychrophilum strains isolated from farmed Atlantic salmon and rainbow trout in Chile was done using phenotypic, antigenic and genetic techniques. Experimental infections were also performed to assess the virulence of two representative isolates and of the type strain. Biochemical and physiological analyses showed that Chilean F. psychrophilum strains, regardless of the host species, constitute a phenotypically very homogeneous group matching with previous descriptions of this pathogen. However, serological assays indicated the existence of antigenic heterogeneity with four patterns of serological reactions. The first group contained most (14 of 20) of the F. psychrophilum isolates showing cross-reaction with the antisera obtained against Atlantic salmon and rainbow trout isolates. Group 2 corresponded to four other rainbow trout isolates (1658, 1731, 1762 and 29009) that did not agglutinate with anti-1150 serum. Two minor serological groups were identified for the remaining isolates (Groups 3 and 4). Marked homogeneity was also revealed by genetic studies including 16S rRNA alleles, random amplified polymorphic DNA and REP-PCR showing that a major genetic group of F. psychrophilum may be dominant in disease outbreaks in farms. Restriction fragment length polymorphism of PCR analysis showed that gyrase genotypes B-S or B-R were found in Chilean isolates from rainbow trout and Atlantic salmon, whereas genotype A was not found. Virulence assays using Atlantic salmon indicated no relationship between the degree of pathogenicity and the host origin of the F. psychrophilum strains. [source] Nocardiosis in large yellow croaker, Larimichthys crocea (Richardson)JOURNAL OF FISH DISEASES, Issue 6 2005G-L Wang Abstract An epizootic in seawater-cage reared large yellow croaker, Larimichthys crocea, in China was caused by a Nocardia sp. from August to October 2003. The cumulative mortality rate was 15% and the diseased fish were 16 months old with individual length varying from 25 to 30 cm. Multiple, white nodules, 0.1,0.2 cm in diameter, were scattered on the heart, spleen and kidney. The morphology of isolated bacteria from Lowenstein,Jensen medium and tryptic soy agar was bead-like or long, slender, filamentous rods. Experimental infection indicated that the isolated bacterium was the pathogen responsible for the mortalities. A partial sequence of the 16S rRNA gene of the organism and the type strain of Nocardia seriolae JCM 3360T (Z36925) formed a monophyletic clade with a high sequence similarity of 99.9%. Based on the morphological, physiological, biological properties and the phylogenetic analysis, the pathogenic organism was identified as N. seriolae. This is the first report on N. seriolae -infected large yellow croaker in aquaculture. [source] Analysis of exotoxins produced by atypical isolates of Aeromonas salmonicida, by enzymatic and serological methodsJOURNAL OF FISH DISEASES, Issue 1 2003B K Gudmundsdóttir Abstract In this study, exotoxins produced by 62 Aeromonas salmonicida strains and the bacterium Haemophilus piscium were analysed. Enzymatic assays, zymograms and serological detection were used to monitor secretion by bacterial strains of the previously described exotoxins P1, GCAT and AsaP1 and also the extracellular P2 metallo-gelatinase and a serine caseinase, which is different from the P1 protease and has not yet been characterized. Based on the results, the strains were divided into five groups. One comprised the type strains for A. salmonicida ssp. masoucida, H. piscium and 36% of the atypical isolates, and another, a type strain for A. salmonicida ssp. smithia together with 14% of the atypical isolates. A second type strain of A. salmonicida ssp. smithia was grouped with 8% of the atypical isolates. The largest group contained the type strains for A. salmonicida ssp. achromogenes and 38% of the atypical isolates. The type strains for A. salmonicida ssp. salmonicida were in the last group with all the four typical strains and 4% of the atypical isolates. The combination of zymogram and serological detection used is recommended as the most reliable method for characterizing A. salmonicida strains according to their exotoxin secretion. [source] Atypical Aeromonas salmonicida infection in naturally and experimentally infected cod, Gadus morhua L.JOURNAL OF FISH DISEASES, Issue 10 2002B Magnadóttir Abstract Cod, Gadus morhua L., of wild origin, were reared at different temperatures for 12 months. During this period, moribund and newly dead fish were examined and samples collected for bacteriology and histopathology. Atypical Aeromonas salmonicida was isolated from 10 individuals reared at or above 7 °C. The isolates were homogeneous with respect to biochemical and antibiogram characters and similar to the ssp. achromogenes National Collection of Industrial and Marine Bacteria, UK, type strain 1110 and reference strains that have been isolated from salmonids and haddock in Iceland. Histopathological analysis of the naturally infected cod showed typical ulceration associated with atypical A. salmonicida infection and also widespread granulomatous formations. One-year-old cod of farmed origin, kept at 9 °C, received intraperitoneal or intramuscular injection with different doses of atypical A. salmonicida, isolated from the above wild cod. Mortalities were monitored for 28 days and the LD50 calculated. The route of bacterial injection influenced the mortality rate and LD50 value and affected, to some extent, the pathological changes observed and humoral immune parameters. Pathological changes, including haemorrhage, early stages of granuloma formation and necrotic changes, were seen in several organs. Infection appeared to induce non-specific antibody activity against trinitrophenyl (TNP)-haptenated protein and may have activated the complement system. Specific antibody response against atypical A. salmonicida was not detected. [source] A differential medium for lactic acid-producing bacteria in a mixed cultureLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2008H.M. Lee Abstract Aims:, Modified deMan-Rogosa Sharpe agar containing bromophenol blue (mMRS-BPB) was tested as a medium for counting and differentiation of each lactic acid-producing bacterium (LAB), especially in a mixed culture. Methods and Results:, Type strains of 10 LAB species (Lactobacillus acidophilus, L. brevis, L. bulgaricus, L. gasseri, L. paracasei, L. plantarum, L. reuteri, Weissella confusa, Bifidobacterium bifidum and B. infantis) and five commercial yogurts were inoculated on plate count agar with bromocresol purple, mMRS, and mMRS-BPB. Each type strain showed more clearly formed colonies on the three media under anaerobic conditions than under aerobic conditions. Especially each type strain produced colonies with specific characteristics of each species on mMRS-BPB. Commercial yogurts produced the largest number of colonies with various shapes and colours on mMRS-BPB. Conclusions:, Modified deMan-Rogosa Sharpe agar containing bromophenol blue under anaerobic conditions is appropriate for counting and differentiating each LAB in a mixed culture. Significance and Impact of the Study:, Modified deMan-Rogosa Sharpe agar containing bromophenol blue will be useful in isolation and enumeration of each LAB from fermented foods as well as intestinal microflora. [source] Role of Alicyclobacillus acidoterrestris in the development of a disinfectant taint in shelf-stable fruit juiceLETTERS IN APPLIED MICROBIOLOGY, Issue 1 2003N. Jensen Abstract Aims: This study was undertaken to identify the bacterium and metabolic products contributing to a disinfectant taint in shelf-stable fruit juice and to determine some of the growth conditions for the organism. Methods and Results: Microbiological examination of tainted and untainted fruit juice drinks detected low numbers of acid-dependent, thermotolerant, spore-forming bacteria in the tainted juices only. The presence of ,-cyclohexyl fatty acids was confirmed in two of the isolates by cell membrane fatty acid analysis. The isolates were subsequently identified as Alicyclobacillus acidoterrestris by partial 16S rDNA sequencing. Studies on the isolates showed growth at pH 2·5,6·0 and 19·5,58 °C. Gas chromatography/mass spectrometry (GC/MS) was used to identify and quantify 2,6-dibromophenol (2,6-DBP) and 2,6-dichlorophenol (2,6-DCP) in the tainted juice. Challenge studies in a mixed fruit drink inoculated with the two isolates and the type strain of A. acidoterrestris, incubated at 44,46 °C for 4 d, showed the production of both metabolites, which were confirmed and quantified by GC/MS. Conclusions: The results show that A. acidoterrestris can produce 2,6-DBP and 2,6-DCP in shelf-stable juices. Significance and Impact of the Study: This is the first report detailing experimental methodology showing that A. acidoterrestris can produce 2,6-DCP in foods. Control of storage temperatures (to <,20 °C) immediately after processing may provide an effective control measure for the fruit juice industry to prevent spoilage by A. acidoterrestris. [source] | ||||||||||||||||||||||||||||