A comparative proteomic analysis was utilized to evaluate similarities and differences in membrane samples derived from the cariogenic bacterium Streptococcus mutans, including the wild-type strain and four mutants devoid of protein translocation machinery components, specifically ?ffh, ?yidC1, ?yidC2, or ?ffh/yidC1. The purpose of this work was to determine the extent to which the encoded proteins operate individually or in concert with one another and to identify the potential substrates of the respective pathways. Ffh is the principal protein component of the signal recognition particle (SRP), while yidC1 and yidC2 are dual paralogs encoding members of the YidC/Oxa/Alb family of membrane-localized…
Streptococcus mutans LAB761 has been isolated from dental plaque collected from a child with severe caries. We report here the complete genome sequence of S. mutans strain LAB761, which has a chromosome of 2.0 Mb. The genome sequence reported herein contains several loci encoding double-glycine-motif peptides and lantibiotic and nonlantibiotic bacteriocins.
A novel facultative anaerobic and Gram-stain-positive coccus, designated strain ChDC F135T, was isolated from human subgingival dental plaque of periodontitis lesion and was characterized by polyphasic taxonomic analysis. The 16S rRNA gene (16S rDNA) sequence of strain ChDC F135T was closest to that of Streptococcus sinensis HKU4T (98.2%), followed by Streptococcus intermedia SK54T (97.0%), Streptococcus constellatus NCTC11325T (96.0%), and Streptococcus anginosus NCTC 10713T (95.7%). In contrast, phylogenetic analysis based on the superoxide dismutase gene (sodA) and the RNA polymerase beta-subunit gene (rpoB) showed that the nucleotide sequence similarities of strain ChDC F135T were highly similar to the corresponding genes of…
A novel facultative anaerobic, Gram-stain-negative coccus, designated strain ChDC B345T, was isolated from human pericoronitis lesion and was characterized by polyphasic taxonomic analysis. The 16S ribosomal RNA gene (16S rDNA) sequence revealed that the strain belonged to the genus Streptococcus. The 16S rDNA sequence of strain ChDC B345T was most closely related to those of Streptococcus mitis NCTC 12261T (99.5%) and Streptococcus pseudopneumoniae ATCC BAA-960T (99.5%). Complete genome of strain ChDC B345T was 1,972,471 bp in length and the G?+?C content was 40.2 mol%. Average nucleotide identity values between strain ChDC B345T and S. pseudopneumoniae ATCC BAA-960T or S. mitis NCTC 12261T were…
The use of bacteriophages represents a valid alternative to conventional antimicrobial treatments, overcoming the widespread bacterial antibiotic resistance phenomenon. In this work, we evaluated whether biomimetic hydroxyapatite (HA) nanocrystals are able to enhance some properties of bacteriophages. The final goal of this study was to demonstrate that biomimetic HA nanocrystals can be used for bacteriophage delivery in the context of bacterial infections, and contribute – at the same time – to enhance some of the biological properties of the same bacteriophages such as stability, preservation, antimicrobial activity, and so on.Phage isolation and characterization were carried out by using Mitomycin C…
Three Lactobacillus plantarum strains ATG-K2, ATG-K6, and ATG-K8 were isolated from Kimchi, a Korean traditional fermented food, and their probiotic potentials were examined. All three strains were free of antibiotic resistance, hemolysis, and biogenic amine production and therefore assumed to be safe, as supported by whole genome analyses. These strains demonstrated several basic probiotic functions including a wide range of antibacterial activity, bile salt hydrolase activity, hydrogen peroxide production, and heat resistance at 70°C for 60 s. Further studies of antimicrobial activities against Candida albicans and Gardnerella vaginalis revealed growth inhibitory effects from culture supernatants, coaggregation effects, and killing effects…
Respiratory ammonification and denitrification are two evolutionarily unrelated dissimilatory nitrogen (N) processes central to the global N cycle, the activity of which is thought to be controlled by carbon (C) to nitrate (NO3-) ratio. Here we find that Intrasporangium calvum C5, a novel dual-pathway denitrifier/respiratory ammonifier, disproportionately utilizes ammonification rather than denitrification when grown under low C concentrations, even at low C:NO3- ratios. This finding is in conflict with the paradigm that high C:NO3- ratios promote ammonification and low C:NO3- ratios promote denitrification. We find that the protein atomic composition for denitrification modules (NirK) are significantly cost minimized for C…
In this PacBio User Group Meeting presentation, PacBio scientist Meredith Ashby shared several examples of analysis — from full-length 16S sequencing to shotgun sequencing — showing how SMRT Sequencing enables accurate representation for metagenomics and microbiome characterization, in some cases even without fully assembling genomes. New updates will provide users with a dedicated microbial assembly pipeline, optimized for all classes of bacteria, as well as increased multiplexing on the Sequel II System, now with 48 validated barcoded adapters. That throughput could reduce the cost of microbial analysis substantially.
Understanding interactions among plants and the complex communities of organisms living on, in and around them requires more than one experimental approach. A new method for de novo metagenome assembly, PacBio HiFi sequencing, has unique strengths for determining the functional capacity of metagenomes. With HiFi sequencing, the accuracy and median read length of unassembled data outperforms the quality metrics for many existing assemblies generated with other technologies, enabling cost-competitive recovery of full-length genes and operons even from rare species. When paired with the ability to close the genomes of even challenging isolates like Xanthomonas, the PacBio Sequel II System is…
Recent work comparing metagenomic sequencing methods indicates that a comprehensive picture of the taxonomic and functional diversity of complex communities will be difficult to achieve with short-read technology alone. While the lower cost of short reads has enabled greater sequencing depth, the greater contiguity of long-read assemblies and lack of GC bias in SMRT Sequencing has enabled better gene finding. However, since long-read assembly requires high coverage for error correction, the benefits of unbiased coverage have in the past been lost for low abundance species. SMRT Sequencing performance improvements and the introduction of the Sequel II System has enabled a…
Recent work comparing metagenomic sequencing methods indicates that a comprehensive picture of the taxonomic and functional diversity of complex communities will be difficult to achieve with one sequencing technology alone. While the lower cost of short reads has enabled greater sequencing depth, the greater contiguity of long-read assemblies and lack of GC bias in SMRT Sequencing has enabled better gene finding. However, since long-read assembly typically requires high coverage for error correction, these benefits have in the past been lost for low-abundance species. The introduction of the Sequel II System has enabled a new, higher throughput, assembly-optional data type that…
While the utility of Single Molecule, Real-Time (SMRT) Sequencing for de novo assembly and finishing of bacterial isolates is well established, this technology has not yet been widely applied to shotgun sequencing of microbial communities. In order to demonstrate the feasibility of this approach, we sequenced genomic DNA from the Microbial Mock Community B of the Human Microbiome Project
The constituents and intra-communal interactions of microbial populations have garnered increasing interest in areas such as water remediation, agriculture and human health. One popular, efficient method of profiling communities is to amplify and sequence the evolutionarily conserved 16S rRNA sequence. Currently, most targeted amplification focuses on short, hypervariable regions of the 16S sequence. Distinguishing information not spanned by the targeted region is lost and species-level classification is often not possible. SMRT Sequencing easily spans the entire 1.5 kb 16S gene, and in combination with highly-accurate single-molecule sequences, can improve the identification of individual species in a metapopulation. However, when amplifying…
The constituents and intra-communal interactions of microbial populations have garnered increasing interest in areas such as water remediation, agriculture and human health. Amplification and sequencing of the evolutionarily conserved 16S rRNA gene is an efficient method of profiling communities. Currently, most targeted amplification focuses on short, hypervariable regions of the 16S sequence. Distinguishing information not spanned by the targeted region is lost, and species-level classification is often not possible. PacBio SMRT Sequencing easily spans the entire 1.5 kb 16S gene in a single read, producing highly accurate single-molecule sequences that can improve the identification of individual species in a metapopulation.However,…