Comparative genomics of the Bifidobacterium brevetaxon

Bifidobacteria constitute a specific group of commensal bacteria typically found in the gastrointestinal tract (GIT) of humans and other mammals. Bifidobacterium breve strains are numerically prevalent among the gut microbiota of many healthy breastfed infants. In the present study, we investigated glycosulfatase activity in a bacterial isolate from a nursling stool sample, B. breve UCC2003. Two putative sulfatases were identified on the genome of B. breve UCC2003. The sulfated monosaccharide N-acetylglucosamine-6-sulfate (GlcNAc-6-S) was shown to support the growth of B. breve UCC2003, while N-acetylglucosamine-3-sulfate, N-acetylgalactosamine-3-sulfate, and N-acetylgalactosamine-6-sulfate did not support appreciable growth. By using a combination of transcriptomic and functional genomic approaches, a gene cluster designated ats2 was shown to be specifically required for GlcNAc-6-S metabolism. Transcription of the ats2 cluster is regulated by a repressor open reading frame kinase (ROK) family transcriptional repressor. This study represents the first description of glycosulfatase activity within the Bifidobacterium genus. IMPORTANCEBifidobacteria are saccharolytic organisms naturally found in the digestive tract of mammals and insects. Bifidobacterium breve strains utilize a variety of plant-and host-derived carbohydrates that allow them to be present as prominent members of the infant gut microbiota as well as being present in the gastrointestinal tract of adults. In this study, we introduce a previously unexplored area of carbohydrate metabolism in bifidobacteria, namely, the metabolism of sulfated carbohydrates. B. breve UCC2003 was shown to metabolize N-acetylglucosamine-6-sulfate (GlcNAc-6-S) through one of two sulfatase-encoding gene clusters identified on its genome. GlcNAc-6-S can be found in terminal or branched positions of mucin oligosaccharides, the glycoprotein component of the mucous layer that covers the digestive tract. The results of this study provide further evidence of the ability of this species to utilize mucin-derived sugars, a trait which may provide a competitive advantage in both the infant gut and adult gut. The genus Bifidobacterium represents one of the major components of the intestinal microbiota of breastfed infants (1-5) while also typically constituting between 2% and 10% of the adult intestinal microbiota (6-11). Bifidobacteria are saccharolytic microorganisms whose ability to colonize and survive in the large intestine is presumed to depend on the ability to metabolize complex carbohydrates present in this environment (12, 13). Certain bifidobacterial species, including Bifidobacterium longum subsp. longum, Bifidobacterium adolescentis, and Bifidobacterium breve, utilize a range of plant/diet-derived oligosaccharides such as raffinose, arabinoxylan, galactan, and cellodextrins (14-20). Bifidobacterial metabolism of human milk oligosaccharides (HMOs) is also well described, with the typically infant-derived species B. longum subsp. infantis and Bifidobacterium bifidum ...

Section: Resultssupporting

confidence: 53%

Glycosulfatase-Encoding Gene Cluster in Bifidobacterium breve UCC2003

Egan

Jiang

Motherway

et al. 2016

“…All type strains belonging to the Bifidobacterium genus and several previously characterized strains belonging to species present on the qualified presumption of safety (QPS) list (11,13,19,(40)(41)(42)(43)(44) were used in this study (Tables 1 and 2). Cultures were grown under anaerobic conditions (2.99% H 2 , 17.01% CO 2 , and 80% N 2 ) in a chamber (Concept 400; Ruskin) on De Man-Rogosa-Sharpe (MRS) broth (Scharlau Chemie, Barcelona, Spain) supplemented with 0.05% (wt/vol) L-cysteine hydrochloride and were incubated at 37°C.…”

Section: Methodsmentioning

confidence: 99%

Prevalence of Antibiotic Resistance Genes among Human Gut-Derived Bifidobacteria

Duranti

Lugli

Mancabelli

et al. 2017

Self Cite

“…The reconstruction of the pan-genome of this taxon revealed a wide genetic variability for genes previously characterized as being involved in the utilization of the carbohydrates ribose, sucrose, and raffinose, as well as the plant-derived polysaccharides starch, galactan, and cellodextrin (73).…”

Section: Figmentioning

confidence: 99%

“…Notably, the core genome of B. breve encompasses genes that are predicted to encode enzymes involved in the uptake and utilization of host-derived mono/oligosaccharides, in particular those derived from mucin and HMOs (73). Examples include gene clusters predicted to be involved in the metabolism of sialic acid, lacto-N-biose, fucose, and N-linked glycans.…”

Section: Figmentioning

confidence: 99%

Genomics of the Genus Bifidobacterium Reveals Species-Specific Adaptation to the Glycan-Rich Gut Environment

Milani

Turroni

Duranti

et al. 2016

Self Cite

183

136

b Bifidobacteria represent one of the dominant microbial groups that occur in the gut of various animals, being particularly prevalent during the suckling period of humans and other mammals. Their ability to compete with other gut bacteria is largely attributed to their saccharolytic features. Comparative and functional genomic as well as transcriptomic analyses have revealed the genetic background that underpins the overall saccharolytic phenotype for each of the 47 bifidobacterial (sub)species representing the genus Bifidobacterium, while also generating insightful information regarding carbohydrate resource sharing and crossfeeding among bifidobacteria. The abundance of bifidobacterial saccharolytic features in human microbiomes supports the notion that metabolic accessibility to dietary and/or host-derived glycans is a potent evolutionary force that has shaped the bifidobacterial genome.