Genome analysis of two Lactobacillus plantarum strains, LLY-606 and pc-26, for evaluating their potential as probiotics.

Lactobacillus plantarum was not only one of the most popular probiotics, but also one of the most versatile lactic acid bacteria. L. plantarum LLY-606 and L. plantarum pc-26 are strains isolated from human gut that are intended to be explored as probiotics. In this study, the genome sequences of LLY-606 and pc-26 were sequenced, and multiple genes related to probiotic properties were analyzed. First, the pathogenicity of these strains was evaluated, and antibiotic resistance genes were surveyed at the whole genome level to determine their primary safety. And then, genes for stress response, plantaricin (pln) biosynthesis, extracellular polysaccharide (EPS) biosynthesis, and bile salt hydrolase (BSH) were analyzed to evaluate their industrial utilization, adhesive capacity, and survival ability in gut, which were properties fundamental for probiotic strains. The physiological features assured by these genes were assayed in vitro. The strains were then evaluated in vivo for their ability to lower cholesterol, and they were both found to be effective in improving hypercholesterolemia in golden hamsters. In this study, a genetic pre-evaluation was conducted through genome analysis combined with in vitro physiological assay, and the probiotic properties of these strains were verified in vivo.

A Comprehensive Genome Survey Provides Novel Insights into Bile Salt Hydrolase (BSH) in Lactobacillaceae.

Bile salt hydrolase (BSH) is a well-known enzyme that has been commonly characterized in probiotic bacteria, as it has cholesterol-lowering effects. However, its molecular investigations are scarce. Here, we build a local database of BSH sequences from Lactobacillaceae (BSH⁻SDL), and phylogenetic analysis and homology searches were employed to elucidate their comparability and distinctiveness among species. Evolutionary study demonstrates that BSH sequences in BSH⁻SDL are divided into five groups, named BSH A, B, C, D and E here, which can be the genetic basis for BSH classification and nomenclature. Sequence analysis suggests the differences between BSH-active and BSH-inactive proteins clearly, especially on site 82. In addition, a total of 551 BSHs from 107 species are identified from 451 genomes of 158 Lactobacillaceae species. Interestingly, those bacteria carrying various copies of BSH A or B can be predicted to be potential cholesterol-lowering probiotics, based on the results of phylogenetic analysis and the subtypes that those previously reported BSH-active probiotics possess. In summary, this study elaborates the molecular basis of BSH in Lactobacillaceae systematically, and provides a novel methodology as well as a consistent standard for the identification of the BSH subtype. We believe that high-throughput screening can be efficiently applied to the selection of promising candidate BSH-active probiotics, which will advance the development of healthcare products in cholesterol metabolism.

Updated foxtail millet genome assembly and gene mapping of nine key agronomic traits by resequencing a RIL population.

Foxtail millet (Setaria italica) provides food and fodder in semi-arid regions and infertile land. Resequencing of 184 foxtail millet recombinant inbred lines (RILs) was carried out to aid essential research on foxtail millet improvement. A total 483 414 single nucleotide polymorphisms were determined. Bin maps were constructed based on the RILs' recombination data. Based on the high-density bin map, we updated Zhanggu reference with 416 Mb after adding 16 Mb unanchored scaffolds and Yugu reference with some assembly error correction and 3158 gaps filled. Quantitative trait loci (QTL) mapping of nine agronomic traits was done based on this RIL population, five of which were controlled by a single gene. Meanwhile, two QTLs were found for plant height, and a candidate gene showed 89% identity to the known rice gibberellin-synthesis gene sd1. Three QTLs were found for the trait of heading date. The whole genome resequencing and QTL mapping provided important tools for foxtail millet research and breeding. Resequencing of the RILs could also provide an effective way for high-quality genome assembly and gene identification.

Omics-based interpretation of synergism in a soil-derived cellulose-degrading microbial community.

Reaching a comprehensive understanding of how nature solves the problem of degrading recalcitrant biomass may eventually allow development of more efficient biorefining processes. Here we interpret genomic and proteomic information generated from a cellulolytic microbial consortium (termed F1RT) enriched from soil. Analyses of reconstructed bacterial draft genomes from all seven uncultured phylotypes in F1RT indicate that its constituent microbes cooperate in both cellulose-degrading and other important metabolic processes. Support for cellulolytic inter-species cooperation came from the discovery of F1RT microbes that encode and express complimentary enzymatic inventories that include both extracellular cellulosomes and secreted free-enzyme systems. Metabolic reconstruction of the seven F1RT phylotypes predicted a wider genomic rationale as to how this particular community functions as well as possible reasons as to why biomass conversion in nature relies on a structured and cooperative microbial community.