High-quality draft genome sequence of Bifidobacterium longum E18, isolated from a healthy adult

Bifidobacteria are important gastrointestinal commensals of a number of animals, including humans, and various beneficial effects on host health have been attributed to them. Here, we announce the noncontiguous finished genome sequence of Bifidobacterium longum E18, isolated from a healthy adult, which reveals traits involved in its interaction with the host

Improved adhesive properties of recombinant bifidobacteria expressing the <it>Bifidobacterium bifidum</it>-specific lipoprotein BopA

<p>Abstract</p> <p>Background</p> <p>Bifidobacteria belong to one of the predominant bacterial groups in the intestinal microbiota of infants and adults. Several beneficial effects on the health status of their human hosts have been demonstrated making bifidobacteria interesting candidates for probiotic applications. Adhesion of probiotics to the intestinal epithelium is discussed as a prerequisite for colonisation of and persistence in the gastrointestinal tract.</p> <p>Results</p> <p>In the present study, 15 different strains of bifidobacteria were tested for adhesion. <it>B. bifidum</it> was identified as the species showing highest adhesion to all tested intestinal epithelial cell (IEC) lines. Adhesion of <it>B. bifidum</it> S17 to IECs was strongly reduced after treatment of bacteria with pronase. These results strongly indicate that a proteinaceous cell surface component mediates adhesion of <it>B. bifidum</it> S17 to IECs. <it>In silico</it> analysis of the currently accessible <it>Bifidobacterium</it> genomes identified <it>bopA</it> encoding a lipoprotein as a <it>B. bifidum</it>-specific gene previously shown to function as an adhesin of <it>B. bifidum</it> MIMBb75. The <it>in silico</it> results were confirmed by Southern Blot analysis. Furthermore, Northern Blot analysis demonstrated that <it>bopA</it> is expressed in all <it>B. bifidum</it> strains tested under conditions used to cultivate bacteria for adhesion assays. The BopA gene was successfully expressed in <it>E. coli</it> and purified by Ni-NTA affinity chromatography as a C-terminal His₆-fusion. Purified BopA had an inhibitory effect on adhesion of <it>B. bifidum</it> S17 to IECs. Moreover, <it>bopA</it> was successfully expressed in <it>B. bifidum</it> S17 and <it>B. longum/infantis</it> E18. Strains overexpressing <it>bopA</it> showed enhanced adhesion to IECs, clearly demonstrating a role of BopA in adhesion of <it>B. bifidum</it> strains.</p> <p>Conclusions</p> <p>BopA was identified as a <it>B. bifidum</it>-specific protein involved in adhesion to IECs. <it>Bifidobacterium</it> strains expressing <it>bopA</it> show enhanced adhesion. Our results represent the first report on recombinant bifidobacteria with improved adhesive properties.</p

Complete Genome Sequence of Bifidobacterium bifidum S17▿

Here, we report on the first completely annotated genome sequence of a Bifidobacterium bifidum strain. B. bifidum S17, isolated from feces of a breast-fed infant, was shown to strongly adhere to intestinal epithelial cells and has potent anti-inflammatory activity in vitro and in vivo. The genome sequence will provide new insights into the biology of this potential probiotic organism and allow for the characterization of the molecular mechanisms underlying its beneficial properties

Comparative genomics of the Bifidobacterium breve taxon

BACKGROUND: Bifidobacteria are commonly found as part of the microbiota of the gastrointestinal tract (GIT) of a broad range of hosts, where their presence is positively correlated with the host's health status. In this study, we assessed the genomes of thirteen representatives of Bifidobacterium breve, which is not only a frequently encountered component of the (adult and infant) human gut microbiota, but can also be isolated from human milk and vagina. RESULTS: In silico analysis of genome sequences from thirteen B. breve strains isolated from different environments (infant and adult faeces, human milk, human vagina) shows that the genetic variability of this species principally consists of hypothetical genes and mobile elements, but, interestingly, also genes correlated with the adaptation to host environment and gut colonization. These latter genes specify the biosynthetic machinery for sortase-dependent pili and exopolysaccharide production, as well as genes that provide protection against invasion of foreign DNA (i.e. CRISPR loci and restriction/modification systems), and genes that encode enzymes responsible for carbohydrate fermentation. Gene-trait matching analysis showed clear correlations between known metabolic capabilities and characterized genes, and it also allowed the identification of a gene cluster involved in the utilization of the alcohol-sugar sorbitol. CONCLUSIONS: Genome analysis of thirteen representatives of the B. breve species revealed that the deduced pan-genome exhibits an essentially close trend. For this reason our analyses suggest that this number of B. breve representatives is sufficient to fully describe the pan-genome of this species. Comparative genomics also facilitated the genetic explanation for differential carbon source utilization phenotypes previously observed in different strains of B. breve