RESUMO
In a previous study on bifidobacterial distribution in New World monkeys, six strains belonging to the Bifidobacteriaceae were isolated from faecal samples of baby common marmosets (Callithrix jacchus L.). All the isolates were Gram-positive-staining, anaerobic, asporogenous and fructose-6-phosphate phosphoketolase-positive. Comparative analysis of 16S rRNA gene sequences revealed relatively low levels of similarity (maximum identity 96 %) to members of the genus Bifidobacterium, and placed the isolates in three independent clusters: strains of cluster I (MRM_5.9T and MRM_5.10) and cluster III (MRM_5.18T and MRM_9.02) respectively showed 96.4 and 96.7 % 16S rRNA gene sequence similarity to Bifidobacterium callitrichos DSM 23973T, while strains of cluster II (MRM_8.14T and MRM_9.14) showed 95.4 % similarity to Bifidobacterium stellenboschense DSM 23968T. Phylogenetic analysis of partial hsp60 and clpC gene sequences supported an independent phylogenetic position of each cluster from each other and from the related type strains B. callitrichos DSM 23973T and B. stellenboschense DSM 23968T. Clusters I, II and III respectively showed DNA G+C contents of 64.9-65.1, 56.4-56.7 and 63.1-63.7âmol%. The major cellular fatty acids of MRM_5.9T were C14 : 0, C16 : 0 and C18 : 1ω9c dimethylacetal, while C16 : 0 was prominent in strains MRM_5.18T and MRM_8.14T, followed by C18 : 1ω9c and C14 : 0. Biochemical profiles and growth parameters were recorded for all the isolates. Based on the data provided, the clusters represent three novel species, for which the names Bifidobacterium myosotis sp. nov. (type strain MRM_5.9T = DSM 100196T = JCM 30796T), Bifidobacterium hapali sp. nov. (type strain MRM_8.14T = DSM 100202T = JCM 30799T) and Bifidobacterium tissieri sp. nov. (type strain MRM_5.18T = DSM 100201T = JCM 30798T) are proposed.
Assuntos
Callithrix/microbiologia , Fezes/microbiologia , Filogenia , Aldeído Liases/metabolismo , Animais , Proteínas de Bactérias/genética , Técnicas de Tipagem Bacteriana , Composição de Bases , Bifidobacterium/classificação , Bifidobacterium/genética , Bifidobacterium/isolamento & purificação , Chaperonina 60/genética , DNA Bacteriano/genética , Ácidos Graxos/química , Proteínas de Choque Térmico/genética , Dados de Sequência Molecular , Peptidoglicano/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
The species Bifidobacterium longum is currently divided into three subspecies, B. longum subsp. longum, B. longum subsp. infantis and B. longum subsp. suis. This classification was based on an assessment of accumulated information on the species' phenotypic and genotypic features. The three subspecies of B. longum were investigated using genotypic identification [amplified-fragment length polymorphism (AFLP), multilocus sequence analysis (MLSA) and multilocus sequence typing (MLST)]. By using the AFLP and the MLSA methods, we allocated 25 strains of B. longum into three major clusters corresponding to the three subspecies; the cluster comprising the strains of B. longum subsp. suis was further divided into two subclusters differentiable by the ability to produce urease. By using the MLST method, the 25 strains of B. longum were divided into eight groups: four major groups corresponding to the results obtained by AFLP and MLSA, plus four minor disparate groups. The results of AFLP, MLSA and MLST analyses were consistent and revealed a novel subspeciation of B. longum, which comprised three known subspecies and a novel subspecies of urease-negative B. longum, for which the name B. longum subsp. suillum subsp. nov. is proposed, with type strain Su 851(T)=DSM 28597(T)=JCM 19995(T).