Novel Putative Transposable Element Associated with the Subtype E5 Botulinum Toxin Gene Cluster of Neurotoxigenic Clostridium butyricum Type E Strains from China

Previously, a whole-genome comparison of three Clostridium butyricum type E strains from Italy and the United States with different C. botulinum type E strains indicated that the bont/e gene might be transferred between the two clostridia species through transposition. However, transposable elements (TEs) have never been identified close to the bont/e gene. Herein, we report the whole genome sequences for four neurotoxigenic C. butyricum type E strains that originated in China. An analysis of the obtained genome sequences revealed the presence of a novel putative TE upstream of the bont/e gene in the genome of all four strains. Two strains of environmental origin possessed an additional copy of the putative TE in their megaplasmid. Similar putative TEs were found in the megaplasmids and, less frequently, in the chromosomes of several C. butyricum strains, of which two were neurotoxigenic C. butyricum type E strains, and in the chromosome of a single C. botulinum type E strain. We speculate that the putative TE might potentially transpose the bont/e gene at the intracellular and inter-cellular levels. However, the occasional TE occurrence in the clostridia genomes might reflect rare transposition events.

Comparative Genomics and Specific Functional Characteristics Analysis of Lactobacillus acidophilus

Lactobacillus acidophilus is a common kind of lactic acid bacteria usually found in the human gastrointestinal tract, oral cavity, vagina, and various fermented foods. At present, many studies have focused on the probiotic function and industrial application of L. acidophilus. Additionally, dozens of L. acidophilus strains have been genome sequenced, but there has been no research to compare them at the genomic level. In this study, 46 strains of L. acidophilus were performed comparative analyses to explore their genetic diversity. The results showed that all the L. acidophilus strains were divided into two clusters based on ANI values, phylogenetic analysis and whole genome comparison, due to the difference of their predicted gene composition of bacteriocin operon, CRISPR-Cas systems and prophages mainly. Additionally, L. acidophilus was a pan-genome open species with a difference in carbohydrates utilization, antibiotic resistance, EPS operon, surface layer protein operon and other functional gene composition. This work provides a better understanding of L. acidophilus from a genetic perspective, and offers a frame for the biotechnological potentiality of this species.

Genomic Comparison of Insect Gut Symbionts from Divergent Burkholderia Subclades

Stink bugs of the superfamilies Coreoidea and Lygaeoidea establish gut symbioses with environmentally acquired bacteria of the genus Burkholderia sensu lato. In the genus Burkholderia, the stink bug-associated strains form a monophyletic clade, named stink bug-associated beneficial and environmental (SBE) clade (or Caballeronia). Recently, we revealed that members of the family Largidae of the superfamily Pyrrhocoroidea are associated with Burkholderia but not specifically with the SBE Burkholderia; largid bugs harbor symbionts that belong to a clade of plant-associated group of Burkholderia, called plant-associated beneficial and environmental (PBE) clade (or Paraburkholderia). To understand the genomic features of Burkholderia symbionts of stink bugs, we isolated two symbiotic Burkholderia strains from a bordered plant bug Physopellta gutta (Pyrrhocoroidea: Largidae) and determined their complete genomes. The genome sizes of the insect-associated PBE (iPBE) are 9.5 Mb and 11.2 Mb, both of which are larger than the genomes of the SBE Burkholderia symbionts. A whole-genome comparison between two iPBE symbionts and three SBE symbionts highlighted that all previously reported symbiosis factors are shared and that 282 genes are specifically conserved in the five stink bug symbionts, over one-third of which have unknown function. Among the symbiont-specific genes, about 40 genes formed a cluster in all five symbionts; this suggests a “symbiotic island” in the genome of stink bug-associated Burkholderia.

Whole Genome Comparison of Pakistani Corona Virus with Chinese and US Strains along with its Predictive Severity of COVID-19

Recently submitted 784 SARS-nCoV2 whole genome sequences from NCBI Virus database were taken for constructing phylogenetic tree to look into their similarities. Pakistani strain MT240479 (Gilgit1-Pak) was found in close proximity to MT184913 (CruiseA-USA), while the second Pakistani strain MT262993 (Manga-Pak) was neighboring to MT039887 (WI-USA) strain in the constructed cladogram in this article. Afterward, four whole genome SARS-nCoV2 strain sequences were taken for variant calling analysis, those who appeared nearest relative in the earlier cladogram constructed a week time ago. Among those two Pakistani strains each of 29,836 bases were compared against MT263429 from (WI-USA) of 29,889 bases and MT259229 (Wuhan-China) of 29,864 bases. We identified 31 variants in both Pakistani strains, (Manga-Pak vs USA=2del+7SNPs, Manga-Pak vs Chinese=2del+2SNPs, Gilgit1-Pak vs USA=10SNPs, Gilgit1-Pak vs Chinese=8SNPs), which caused alteration in ORF1ab, ORF1a and N genes with having functions of viral replication and translation, host innate immunity and viral capsid formation respectively. These novel variants are assumed to be liable for low mortality rate in Pakistan with 385 as compared to USA with 63,871 and China with 4,633 deaths by May 01, 2020. However functional effects of these variants need further confirmatory studies. Moreover, mutated N & ORF1a proteins in Pakistani strains were also analyzed by 3D structure modelling, which give another dimension of comparing these alterations at amino acid level. In a nutshell, these novel variants are assumed to be linked with reduced mortality of COVID-19 in Pakistan along with other influencing factors, these novel variants would also be useful to understand the virulence of this virus and to develop indigenous vaccines and therapeutics.

A gene based bacterial whole genome comparison toolkit

Most of the computational biology analysis is made comparing genomic features. The nucleotide and amino acid sequence alignments are frequently used in gene function identification and genome comparison. Despite its widespread use, there are limitations in their analysis capabilities that need to be considered but are often overlooked or unknown by many researchers. This paper presents a gene based whole genome comparison toolkit which can be used not only as an alternative and more robust way to compare a set of whole genomes, but, also, to understand the tradeoff of the use of sequence local alignment in this kind of comparison. A study case was performed considering fifteen whole genomes of the Xanthomonas genus. The results were compared with the 16S rRNA-processing protein RimM phylogeny and some thresholds for the use of sequence alignments in this kind of analysis were discussed.