Bifidobacteria are probiotic bacteria with multiple health-promoting properties for human being. The global market for probiotics, especially for bifidobacteria is booming. However, the entire market is still at an ea...Bifidobacteria are probiotic bacteria with multiple health-promoting properties for human being. The global market for probiotics, especially for bifidobacteria is booming. However, the entire market is still at an early stage as there is nearly no fine products developed yet except the whole bacterial cells. The maturation of metabolomics technologies make it possible to study complex mixture with high-throughput, comprehensive maps and libraries. Therefore, we prospect that metabolomics studies mainly based on liquid/gas chromatography-mass spectrometry (LC/GC-MS) can deepen our understanding in detail during the study of metabolic mechanisms of bifidobacteria. These studies can be conducted at three phases, including non-targeted, targeted metabolomic analysis of bifidobacteria, and specific metabolites production through metabolic engineering and fermentation. Metabolomic studies of bifidobacteria will allow us to fully explore their metabolic mechanisms and to utilize metabolites that contribute to human health. In particular, bifidobacteria derived conjugated linoleic acids and bacteriocins are two kinds of fined products that may have great potentials in the future and can be used as food additives.展开更多
Surface layer (S-layer) proteins are one of the most commonly observed cell envelope components in both Archaea and Bacteria. It has versatile functions and holds considerable application potential in biotechnology. B...Surface layer (S-layer) proteins are one of the most commonly observed cell envelope components in both Archaea and Bacteria. It has versatile functions and holds considerable application potential in biotechnology. Bifidobacteria are representative probiotics conferring health promoting properties. However, there is little study of S-layer in bifidobacteria yet. The distribution and characteristics of S-layer in bifidobacteria are unknown. In this study, search for S-layer protein in the identical protein groups in NCBI yielded 49 hits belonging to bifidobacteria. These proteins were annotated as either “S-layer (domain) protein” or “putative S-layer (y) domain protein” that distributed among 26 species of Bifidobacterium genus. Multiple alignments suggest S-layer proteins are relatively conservative. Phylogenetic analysis of 24 S-layer (domain) protein sequences groups them into three distinct clusters, with the majority species in Cluster-2. S-layer (domain) protein has a universe motif DUF4381, though its function is unknown. Meanwhile, two other motifs CARDB and EphA2_TM involved in cell adhesion and cell signaling respectively, presented in most S-layer (domain) protein in bifidobacteria. All S-layer proteins have a typical N-terminal Sec-dependent signal peptide and a C-terminal trans-membrane region. Homological modeling of representative S-layer proteins from each cluster revealed a few unique structural features. All representative S-layer proteins have a plenty of β-meander motif that exclusively composed by β-barrel structural architectures linked together by hairpin loops.展开更多
文摘Bifidobacteria are probiotic bacteria with multiple health-promoting properties for human being. The global market for probiotics, especially for bifidobacteria is booming. However, the entire market is still at an early stage as there is nearly no fine products developed yet except the whole bacterial cells. The maturation of metabolomics technologies make it possible to study complex mixture with high-throughput, comprehensive maps and libraries. Therefore, we prospect that metabolomics studies mainly based on liquid/gas chromatography-mass spectrometry (LC/GC-MS) can deepen our understanding in detail during the study of metabolic mechanisms of bifidobacteria. These studies can be conducted at three phases, including non-targeted, targeted metabolomic analysis of bifidobacteria, and specific metabolites production through metabolic engineering and fermentation. Metabolomic studies of bifidobacteria will allow us to fully explore their metabolic mechanisms and to utilize metabolites that contribute to human health. In particular, bifidobacteria derived conjugated linoleic acids and bacteriocins are two kinds of fined products that may have great potentials in the future and can be used as food additives.
文摘Surface layer (S-layer) proteins are one of the most commonly observed cell envelope components in both Archaea and Bacteria. It has versatile functions and holds considerable application potential in biotechnology. Bifidobacteria are representative probiotics conferring health promoting properties. However, there is little study of S-layer in bifidobacteria yet. The distribution and characteristics of S-layer in bifidobacteria are unknown. In this study, search for S-layer protein in the identical protein groups in NCBI yielded 49 hits belonging to bifidobacteria. These proteins were annotated as either “S-layer (domain) protein” or “putative S-layer (y) domain protein” that distributed among 26 species of Bifidobacterium genus. Multiple alignments suggest S-layer proteins are relatively conservative. Phylogenetic analysis of 24 S-layer (domain) protein sequences groups them into three distinct clusters, with the majority species in Cluster-2. S-layer (domain) protein has a universe motif DUF4381, though its function is unknown. Meanwhile, two other motifs CARDB and EphA2_TM involved in cell adhesion and cell signaling respectively, presented in most S-layer (domain) protein in bifidobacteria. All S-layer proteins have a typical N-terminal Sec-dependent signal peptide and a C-terminal trans-membrane region. Homological modeling of representative S-layer proteins from each cluster revealed a few unique structural features. All representative S-layer proteins have a plenty of β-meander motif that exclusively composed by β-barrel structural architectures linked together by hairpin loops.
