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Syst Appl Microbiol ; 35(1): 1-6, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22154623


The phylogenetic relationship among the three genera of the family Streptomycetaceae was examined using the small and large subunit ribosomal RNA genes, and the gyrB, rpoB, trpB, atpD and recA genes. The total stretches of the analyzed ribosomal genes were 4.2kb, and those of five protein coding genes were 4.5 kb. The resultant phylogenetic trees confirmed that each genus formed an independent clade in the majority of cases. The G+C contents of rRNA genes were 56.9-58.9 mol%, and those of protein coding genes were 65.4-72.4 mol%, the latter being closer to those of the genomic DNAs. The average nucleotide sequence identity between the organisms were 94.1-96.4% for rRNA genes and 85.7-90.6% for protein coding genes, thus indicating that protein coding genes can give higher resolution than rRNA genes. In addition, the protein coding gene trees were more stable than the rRNA gene trees, supported by higher bootstrap values and other treeing algorithms. Moreover, the genome data of six Streptomyces species indicated that many protein coding genes exhibited higher correlations with genome relatedness. The combined gene sequences were also shown to give a better resolution with higher stability than any single genes, though not necessarily more correlated with genome relatedness. It is evident from this study that the rRNA gene based phylogeny can be misleading, and also that protein coding genes have a number of advantages over the rRNA genes as the phylogenetic markers including a high correlation with the genome relatedness.

Proteínas de Bactérias/genética , Genes de RNAr , Filogenia , Streptomycetaceae/classificação , Streptomycetaceae/genética , Composição de Bases , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Dados de Sequência Molecular , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico
Int J Syst Evol Microbiol ; 61(Pt 11): 2654-8, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21148671


A Gram-reaction-negative, yellow-pigmented, gliding, rod-shaped, aerobic bacterium (RA5-111(T)) was isolated from foreshore soil. The taxonomic status of the novel isolate was determined using a polyphasic approach. On the basis of 16S rRNA gene sequence similarities, strain RA5-111(T) could be assigned to the genus Gramella, with sequence similarities of 97.7, 97.3 and 96.2 % to the type strains of Gramella echinicola, Gramella portivictoriae and Gramella marina, respectively. Chemotaxonomic and phenotypic characteristics also supported the affiliation of strain RA5-111(T) with the genus Gramella. The genomic DNA G+C content was 39.1 mol%. The isolate contained MK-6 as the predominant menaquinone, iso-C(15 : 0), iso-C(17 : 0) 3-OH and a summed feature (iso-C(15 : 0) 2-OH and/or C(16 : 1)ω7c) as major fatty acids, and phosphatidylethanolamine and unknown phospholipids as the polar lipids. DNA-DNA relatedness, phenotypic, genotypic and chemotaxonomic data clearly indicate that the isolate represents a novel species of the genus Gramella, for which the name Gramella gaetbulicola sp. nov. is proposed. The type strain is RA5-111(T) ( = KCTC 23022(T) = JCM 16528(T) = NBRC 106272(T)).

Flavobacteriaceae/classificação , Flavobacteriaceae/isolamento & purificação , Microbiologia do Solo , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/metabolismo , Flavobacteriaceae/genética , Flavobacteriaceae/metabolismo , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética
J Microbiol ; 48(5): 566-72, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21046333


Microbial communities in hot pepper (Capsicum annuum L.) cultivation fields under different cultivation methods were investigated by terminal restriction fragment length polymorphism (T-RFLP) analysis. Rhizosphere soil and leaf samples were collected from control, conventional and nature-friendly cultivation fields between May and July, 2009. Two Bacillus subtilis strains were applied to nature-friendly cultivation fields as biocontrol agents during the sampling period. Relative abundances of bacteria and plant pathogenic fungi related T-RFs were also measured to monitor the effect of biocontrol agents on potential plant pathogenic fungi. In the principal component analysis (PCA) based on T-RFLP profiles, the microbial communities from rhizosphere soil samples in July, including bacteria and fungi, showed distinct difference between nature-friendly cultivation fields and other cultivation fields. However, there was no correlation between cultivation methods and leaf microbial communities at any sampling period. Changes in the abundance of bacteria related T-RF in the rhizosphere of nature-friendly cultivation fields were observed clearly two months after application of biocontrol agent, while the abundance of plant pathogenic fungi related T-RFs significantly decreased.

Capsicum/microbiologia , Metagenoma , Controle Biológico de Vetores/métodos , Raízes de Plantas/microbiologia , Rizosfera , Microbiologia do Solo , Biodiversidade , Impressões Digitais de DNA , Folhas de Planta/microbiologia , Polimorfismo de Fragmento de Restrição