The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform
Wen Xin Chen - One of the best experts on this subject based on the ideXlab platform.
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Numerical Taxonomy and 16s rdna pcr rflp analysis of rhizobial strains isolated from root nodules of cowpea and mung bean grown in different regions of china
Acta Microbiologica Sinica, 2006Co-Authors: Yongfa Zhang, Fengqin Wang, Wen Xin ChenAbstract:Seventy-nine rhizobial strains, isolated from root nodules of cowpea ( Vigna unguiculata ) and mung bean (Vigna radiata ) grown in different regions of China, were studied by a fuzzy cluster analysis of 128 phenotypic characteristics. The phenotypic characterization of these strains showed that most of these strains had high stress resistance. For instance, most of them could grow from pH 5.0 to pH 11.0. Over 85% of these strains could grow well on YMA plate at 37 degrees C and several of them even could grow after a 45 minutes hot shock at 60 degrees C. Some strains had a tolerance to high concentration of Bacitracin (400 microg/mL) . The result of the fuzzy cluster analysis showed that all the strains were clustered into 2 groups, slow growers and fast growers, at the similarity level of 63.5% . At the similarity level of 79 %, there were 7 subgroups further separated. Based upon the result of the Numerical Taxonomy, these strains together with 22 reference stains were analyzed by the 16S rDNA PCR-RFLP. Thirty-four genotype profiles were obtained from the fingerprinting of the 16S rDNA PCR-RFLP. These strains were analyzed by GelCompare II software and clustered into 7 groups at the similarity level of 91% , which were consonant with the 7 subgroups clustered at the similarity level of 79% in Numerical Taxonomy. The results of Numerical Taxonomy and 16S rDNA PCR-RFLP analysis showed that all of the seventy-nine rhizobial Bradyrhizobium, strains isolated from root nodules of cowpea and mung bean were clustered into four genera: Agrobacterium, Rhizobium and Sinorhizobium, respectively. An individual clade without any reference stains, which was composed of CCBAU 45071, CCBAU 45111-1 and CCBAU 45248, might be a new species of Rhizobium. Overall, the study results demonstrated a high phenotypic and phylogenetic diversity of rhizobial strains nodulating cowpea and mung bean grown in different geographic regions of China.
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Numerical Taxonomy and dna relatedness of tropical rhizobia isolated from hainan province china
International Journal of Systematic and Evolutionary Microbiology, 1994Co-Authors: Junlian Gao, Jianguang Sun, En Tao Wang, Wen Xin ChenAbstract:A total of 63 strains of rhizobia isolated from Hainan Province, a tropical region of the People's Republic of China, and 27 representative strains belonging to the genera Rhizobium, Bradyrhizobium, and Agrobacterium were compared by performing Numerical Taxonomy, DNA hybridization, and DNA base composition analysis to determine the relationships among these rhizobia. The results indicated that the strains isolated from Hainan Province fell into two distinct phena, the slowly growing rhizobia and the fast-growing rhizobia. The slowly growing rhizobia, which formed three subphena that seemed to be three subspecies, are Bradyrhizobium japonicum strains. The fast-growing strains belong to the genus Rhizobium and might be further divided into three specific groups. Sometimes both slowly growing rhizobia and fast-growing rhizobia were isolated from host plants belonging to the same genus or species or even from the same nodule. There was no correlation between hosts and the distribution of rhizobia in the subphena. Isolates obtained from members of the same host genus or species fell into different groups or subgroups.
Consuelo Esteve - One of the best experts on this subject based on the ideXlab platform.
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phenotypic study by Numerical Taxonomy of strains belonging to the genus aeromonas
Journal of Applied Microbiology, 2002Co-Authors: L Valera, Consuelo EsteveAbstract:Aims: This study was undertaken to cluster and identify a large collection of Aeromonas strains. Methods and Results: Numerical Taxonomy was used to analyse phenotypic data obtained on 54 new isolates taken from water, fish, snails, sputum and 99 type and reference strains. Each strain was tested for 121 characters but only the data for 71 were analysed using the `SSM' and `SJ' coefficients, and the UPGMA clustering algorithm. At SJ values of ≥ 81·6% the strains clustered into 22 phenons which were identified as Aer. jandaei, Aer. hydrophila, Aer. encheleia, Aer. veronii biogroup veronii, Aer. trota, Aer. caviae, Aer. eucrenophila, Aer. ichthiosmia, Aer. sobria, Aer. allosaccharophila, Aer. media, Aer. schubertii and Aer. salmonicida. The species Aer. veronii biogroup sobria was represented by several clusters which formed two phenotypic cores, the first related to reference strain CECT 4246 and the second related to CECT 4835. A good correlation was generally observed among this phenotypic clustering and previous genomic and phylogenetic data. In addition, three new phenotypic groups were found, which may represent new Aeromonas species. Conclusions: The phenetic approach was found to be a necessary tool to delimitate and identify the Aeromonas species. Significance and Impact of the Study: Valuable traits for identifying Aeromonas as well as the possible existence of new Aeromonas species or biotypes are indicated.
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Numerical Taxonomy and nucleic acid studies of Vibrio mediterranei
Systematic and Applied Microbiology, 1992Co-Authors: María J. Pujalte, B.a. Ortiz-conde, Sue E Steven, Consuelo Esteve, Esperanza Garay, Rita R. ColwellAbstract:Summary Vibrio mediterranei was characterized phenotypically and genotypically to determine both intraspecific and interspecific relationships. Phenotypic characterization (ninety-seven tests) of forty-six V. mediterranei strains yielded additional information for improving the species description. Unweighted pair group analysis, using arithmetic averages and the Jaccard similarity coefficient for analysis of phenotypic data for the V. mediterranei strains and twenty-two Vibrio reference strains was done. The phenon recovered by Numerical Taxonomy analysis was confirmed as a separate species by DNA/DNA hybridization. Guanine plus cytosine content was determined to be 42–45 mol% G + C. Analysis of 5S ribosomal ribonucleic acid (rRNA) sequences substantiated the assignment of V. mediterranei to the family Vibrionaceae and indicated a close phylogenetic relationship to V. pelagius and V. tubiashii.
M. C. Fusté - One of the best experts on this subject based on the ideXlab platform.
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Biochemical identification and Numerical Taxonomy of Aeromonas spp. isolated from environmental and clinical samples in Spain.
Journal of applied microbiology, 2002Co-Authors: David Miñana-galbis, Maribel Farfán, J. G. Lorén, M. C. FustéAbstract:To study the phenotypic characteristics of Aeromonas spp. from environmental and clinical samples in Spain and to cluster these strains by Numerical Taxonomy. A collection of 202 Aeromonas strains isolated from bivalve molluscs, water and clinical samples was tested for 64 phenotypic properties; 91% of these isolates were identified at species level. Aeromonas caviae was predominant in bivalve molluscs and Aerom. bestiarum in freshwater samples. Cluster analyses revealed eight different phena: three containing more than one DNA-DNA hybridization group but including strains that belong to the same phenospecies complex (Aerom. hydrophila, Aerom. sobria and Aerom. caviae), Aerom. encheleia, Aerom. trota and three containing unidentified Aeromonas strains isolated from bivalve molluscs. Aeromonas spp. are widely distributed in environmental and clinical sources. A selection of 16 of the phenotypical tests chosen allowed the identification of most isolates (91%), although some strains remain unidentified, mainly isolates from bivalve molluscs, suggesting the presence of new Aeromonas species. Numerical Taxonomy was not in total concordance with the identification of the studied strains. Numerical Taxonomy of Aeromonas strains isolated from different sources revealed the presence of potentially pathogenic Aeromonas spp., especially in bivalve molluscs, and phena with unidentified strains that suggest new Aeromonas species.
Rita R. Colwell - One of the best experts on this subject based on the ideXlab platform.
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Numerical Taxonomy and nucleic acid studies of Vibrio mediterranei
Systematic and Applied Microbiology, 1992Co-Authors: María J. Pujalte, B.a. Ortiz-conde, Sue E Steven, Consuelo Esteve, Esperanza Garay, Rita R. ColwellAbstract:Summary Vibrio mediterranei was characterized phenotypically and genotypically to determine both intraspecific and interspecific relationships. Phenotypic characterization (ninety-seven tests) of forty-six V. mediterranei strains yielded additional information for improving the species description. Unweighted pair group analysis, using arithmetic averages and the Jaccard similarity coefficient for analysis of phenotypic data for the V. mediterranei strains and twenty-two Vibrio reference strains was done. The phenon recovered by Numerical Taxonomy analysis was confirmed as a separate species by DNA/DNA hybridization. Guanine plus cytosine content was determined to be 42–45 mol% G + C. Analysis of 5S ribosomal ribonucleic acid (rRNA) sequences substantiated the assignment of V. mediterranei to the family Vibrionaceae and indicated a close phylogenetic relationship to V. pelagius and V. tubiashii.
Junlian Gao - One of the best experts on this subject based on the ideXlab platform.
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Numerical Taxonomy and dna relatedness of tropical rhizobia isolated from hainan province china
International Journal of Systematic and Evolutionary Microbiology, 1994Co-Authors: Junlian Gao, Jianguang Sun, En Tao Wang, Wen Xin ChenAbstract:A total of 63 strains of rhizobia isolated from Hainan Province, a tropical region of the People's Republic of China, and 27 representative strains belonging to the genera Rhizobium, Bradyrhizobium, and Agrobacterium were compared by performing Numerical Taxonomy, DNA hybridization, and DNA base composition analysis to determine the relationships among these rhizobia. The results indicated that the strains isolated from Hainan Province fell into two distinct phena, the slowly growing rhizobia and the fast-growing rhizobia. The slowly growing rhizobia, which formed three subphena that seemed to be three subspecies, are Bradyrhizobium japonicum strains. The fast-growing strains belong to the genus Rhizobium and might be further divided into three specific groups. Sometimes both slowly growing rhizobia and fast-growing rhizobia were isolated from host plants belonging to the same genus or species or even from the same nodule. There was no correlation between hosts and the distribution of rhizobia in the subphena. Isolates obtained from members of the same host genus or species fell into different groups or subgroups.
