Mycobacteria have been reported to cause a wide range of human diseases. We present the first whole-genome study of a Non-Tuberculous Mycobacterium, Mycobacterium sp. UM_CSW (referred to hereafter as UM_CSW), isolated from a patient diagnosed with bronchiectasis. Our data suggest that this clinical isolate is likely a novel mycobacterial species, supported by clear evidence from molecular phylogenetic, comparative genomic, ANI and AAI analyses. UM_CSW is closely related to the Mycobacterium avium complex. While it has characteristic features of an environmental bacterium, it also shows a high pathogenic potential with the presence of a wide variety of putative genes related to bacterial virulence and shares very similar pathogenomic profiles with the known pathogenic mycobacterial species. Thus, we conclude that this possible novel Mycobacterium species should be tightly monitored for its possible causative role in human infections.
The oral streptococci are spherical Gram-positive bacteria categorized under the phylum Firmicutes which are among the most common causative agents of bacterial infective endocarditis (IE) and are also important agents in septicaemia in neutropenic patients. The Streptococcus mitis group is comprised of 13 species including some of the most common human oral colonizers such as S. mitis, S. oralis, S. sanguinis and S. gordonii as well as species such as S. tigurinus, S. oligofermentans and S. australis that have only recently been classified and are poorly understood at present. We present StreptoBase, which provides a specialized free resource focusing on the genomic analyses of oral species from the mitis group. It currently hosts 104 S. mitis group genomes including 27 novel mitis group strains that we sequenced using the high throughput Illumina HiSeq technology platform, and provides a comprehensive set of genome sequences for analyses, particularly comparative analyses and visualization of both cross-species and cross-strain characteristics of S. mitis group bacteria. StreptoBase incorporates sophisticated in-house designed bioinformatics web tools such as Pairwise Genome Comparison (PGC) tool and Pathogenomic Profiling Tool (PathoProT), which facilitate comparative pathogenomics analysis of Streptococcus strains. Examples are provided to demonstrate how StreptoBase can be employed to compare genome structure of different S. mitis group bacteria and putative virulence genes profile across multiple streptococcal strains. In conclusion, StreptoBase offers access to a range of streptococci genomic resources as well as analysis tools and will be an invaluable platform to accelerate research in streptococci. Database URL: http://streptococcus.um.edu.my.
Mycobacterium cosmeticum is a nontuberculous Mycobacterium recovered from different water sources including household potable water and water collected at nail salon. Individual cases of this bacterium have been reported to be associated with gastrointestinal tract infections. Here we present the first whole-genome study and comparative analysis of two new clinically-derived Mycobacterium sp. UM_RHS (referred as UM_RHS after this) and Mycobacterium sp. UM_NYF (referred as UM_NYF after this) isolated from patients in Indonesia and Malaysia respectively to have a better understanding of the biological characteristic of these isolates. Both strains are likely Mycobacterium cosmeticum as supported by the evidence from molecular phylogenetic, comparative genomic and Average Nucleotide Identity (ANI) analyses. We found the presence of a considerably large number of putative virulence genes in the genomes of UM_RHS and UM_NYF. Interestingly, we also found a horizontally transferred genomic island carrying a putative dsz operon proposing that they may have potential to perform biodesulfization of dibenzothiophene (DBT) that may be effective in cost reduction and air pollution during fuel combustion. This comparative study may provide new insights into M. cosmeticum and serve as an important reference for future functional studies of this bacterial species.
Mycobacteria a genus of Actinobacteria are widespread in nature ranging from soil-dwelling saprophytes to human and animal pathogens. The rate of growth has been a classifying factor for the Mycobacterium spp., dividing them into the rapid growers and the slow growers. Here we have performed a comparative genome study of mycobacterial species in order to get better understanding of their evolution, particularly to understand the distinction between the rapid and slow growers. Our study shows that the slow growers had generally gained and lost more genes compared to the rapid growers. The slow growers might haved eventually lost genes (LivFGMH operon, shaACDEFG genes and MspA porin) that could contribute to the slow growth rate of the slow growers. The genes gained and lost in mycobacteria had eventually helped these bacteria to adapt to different environments and have led to the evolution of the present day rapid and slow growers. Our results also show high number of Mycobacterium abscessus specific genes (811 genes) and some of them are associated with the known bacterial quorum sensing genes that might be important for Mycobacterium abscessus to adapt and survive in variety of unfavorable environments. Mycobacterium abscessus also does not contains genes involved in the bacterial defense system and together with the quorum sensing genes may have contributed to the high gene gain rate of Mycobacterium abscessus.
It is now well established that eukaryote genomes have a common architectural organization into topologically associated domains (TADs) and evidence is accumulating that this organization plays an important role in gene regulation. However, the mechanisms that partition the genome into TADs and the nature of domain boundaries are still poorly understood. We have investigated boundary regions in the Drosophila genome and find that they can be identified as domains of very low H3K27me3. The genome-wide H3K27me3 profile partitions into two states; very low H3K27me3 identifies Depleted (D) domains that contain housekeeping genes and their regulators such as the histone acetyltransferase-containing NSL complex, whereas domains containing moderate-to-high levels of H3K27me3 (Enriched or E domains) are associated with regulated genes, irrespective of whether they are active or inactive. The D domains correlate with the boundaries of TADs and are enriched in a subset of architectural proteins, particularly Chromator, BEAF-32, and Z4/Putzig. However, rather than being clustered at the borders of these domains, these proteins bind throughout the H3K27me3-depleted regions and are much more strongly associated with the transcription start sites of housekeeping genes than with the H3K27me3 domain boundaries. While we have not demonstrated causality, we suggest that the D domain chromatin state, characterised by very low or absent H3K27me3 and established by housekeeping gene regulators, acts to separate topological domains thereby setting up the domain architecture of the genome.
Mycobacterium spp. are renowned for being the causative agent of diseases like leprosy, Buruli ulcer and tuberculosis in human beings. With more and more mycobacterial genomes being sequenced, any knowledge generated from comparative genomic analysis would provide better insights into the biology, evolution, phylogeny and pathogenicity of this genus, thus helping in better management of diseases caused by Mycobacterium spp.With this motivation, we constructed MycoCAP, a new comparative analysis platform dedicated to the important genus Mycobacterium. This platform currently provides information of 2108 genome sequences of at least 55 Mycobacterium spp. A number of intuitive web-based tools have been integrated in MycoCAP particularly for comparative analysis including the PGC tool for comparison between two genomes, PathoProT for comparing the virulence genes among the Mycobacterium strains and the SuperClassification tool for the phylogenic classification of the Mycobacterium strains and a specialized classification system for strains of Mycobacterium abscessus. We hope the broad range of functions and easy-to-use tools provided in MycoCAP makes it an invaluable analysis platform to speed up the research discovery on mycobacteria for researchers. Database URL: http://mycobacterium.um.edu.my.
Mycobacterium iranicum is a newly reported mycobacterial species. We present the first comparative study of M. iranicum UM_TJL and other mycobacteria. We found M. iranicum to have a close genetic association with environmental mycobacteria infrequently associated with human infections. Nonetheless, UM_TJL is also equipped with many virulence genes (some of which appear to be the consequence of transduction-related gene transfer) that have been identified in established human pathogens. Taken all together, our data suggest that M. iranicum is an environmental bacterium adapted for pathogenicity in the human host. This comparative study provides important clues and forms the basis for future functional studies on this mycobacterium.
Mycobacterium abscessus (Ma) is an emerging human pathogen that causes both soft tissue infections and systemic disease. We present the first comparative whole-genome study of Ma strains isolated from patients of wide geographical origin. We found a high proportion of accessory strain-specific genes indicating an open, non-conservative pan-genome structure, and clear evidence of rapid phage-mediated evolution. Although we found fewer virulence factors in Ma compared to M. tuberculosis, our data indicated that Ma evolves rapidly and therefore should be monitored closely for the acquisition of more pathogenic traits. This comparative study provides a better understanding of Ma and forms the basis for future functional work on this important pathogen.
Pangolins are scale-covered mammals, containing eight endangered species. Maintaining pangolins in captivity is a significant challenge, in part because little is known about their genetics. Here we provide the first large-scale sequencing of the critically endangered Manis javanica transcriptomes from eight different organs using Illumina HiSeq technology, yielding ~75 Giga bases and 89,754 unigenes. We found some unigenes involved in the insect hormone biosynthesis pathway and also 747 lipids metabolism-related unigenes that may be insightful to understand the lipid metabolism system in pangolins. Comparative analysis between M. javanica and other mammals revealed many pangolin-specific genes significantly over-represented in stress-related processes, cell proliferation and external stimulus, probably reflecting the traits and adaptations of the analyzed pregnant female M. javanica. Our study provides an invaluable resource for future functional works that may be highly relevant for the conservation of pangolins.
In this study, we first performed whole exome sequencing of DNA from 10 untreated and clinically annotated fresh frozen nasopharyngeal carcinoma (NPC) biopsies and matched bloods to identify somatically mutated genes that may be amenable to targeted therapeutic strategies. We identified a total of 323 mutations which were either non-synonymous (n = 238) or synonymous (n = 85). Furthermore, our analysis revealed genes in key cancer pathways (DNA repair, cell cycle regulation, apoptosis, immune response, lipid signaling) were mutated, of which those in the lipid-signaling pathway were the most enriched. We next extended our analysis on a prioritized sub-set of 37 mutated genes plus top 5 mutated cancer genes listed in COSMIC using a custom designed HaloPlex target enrichment panel with an additional 88 NPC samples. Our analysis identified 160 additional non-synonymous mutations in 37/42 genes in 66/88 samples. Of these, 99/160 mutations within potentially druggable pathways were further selected for validation. Sanger sequencing revealed that 77/99 variants were true positives, giving an accuracy of 78%. Taken together, our study indicated that ~72% (n = 71/98) of NPC samples harbored mutations in one of the four cancer pathways (EGFR-PI3K-Akt-mTOR, NOTCH, NF-κB, DNA repair) which may be potentially useful as predictive biomarkers of response to matched targeted therapies.
Streptococcus gordonii and Streptococcus sanguinis are pioneer colonizers of dental plaque and important agents of bacterial infective endocarditis (IE). To gain a greater understanding of these two closely related species, we performed comparative analyses on 14 new S. gordonii and 5 S. sanguinis strains using various bioinformatics approaches. We revealed S. gordonii and S. sanguinis harbor open pan-genomes and share generally high sequence homology and number of core genes including virulence genes. However, we observed subtle differences in genomic islands and prophages between the species. Comparative pathogenomics analysis identified S. sanguinis strains have genes encoding IgA proteases, mitogenic factor deoxyribonucleases, nickel/cobalt uptake and cobalamin biosynthesis. On the contrary, genomic islands of S. gordonii strains contain additional copies of comCDE quorum-sensing system components involved in genetic competence. Two distinct polysaccharide locus architectures were identified, one of which was exclusively present in S. gordonii strains. The first evidence of genes encoding the CylA and CylB system by the α-haemolytic S. gordonii is presented. This study provides new insights into the genetic distinctions between S. gordonii and S. sanguinis, which yields understanding of tooth surfaces colonization and contributions to dental plaque formation, as well as their potential roles in the pathogenesis of IE.
On record, there are 17 species in the Yersinia genus, of which three are known to be pathogenic to human. While the chromosomal and pYV (or pCD1) plasmid-borne virulence genes as well as pathogenesis of these three species are well studied, their genomic evolution is poorly understood. Our study aims to predict the key evolutionary events that led to the emergence of pathogenic Yersinia species by analyzing gene gain-and-loss, virulence genes, and "Clustered regularly-interspaced short palindromic repeats". Our results suggest that the most recent ancestor shared by the human pathogenic Yersinia was most probably an environmental species that had adapted to the human body. This might have led to ecological specialization that diverged Yersinia into ecotypes and distinct lineages based on differential gene gain-and-loss in different niches. Our data also suggest that Y. pseudotuberculosis group might be the donor of the ail virulence gene to Y. enterocolitica. Hence, we postulate that evolution of human pathogenic Yersinia might not be totally in parallel, but instead, there were lateral gene transfer events. Furthermore, the presence of virulence genes seems to be important for the positive selection of virulence plasmid. Our studies provide better insights into the evolutionary biology of these bacteria.
Many oral bacteria form macroscopic clumps known as coaggregates when mixed with a different species. It is thought that these cell-cell interactions are critical for the formation of mixed-species biofilms such as dental plaque. Here, we assessed the impact of coaggregation between two key initial colonizers of dental plaque, Streptococcus gordonii and Veillonella parvula, on gene expression in each partner. These species were shown to coaggregate in buffer or human saliva. To monitor gene regulation, coaggregates were formed in human saliva and, after 30 minutes, whole-transcriptomes were extracted for sequencing and Dual RNA-Seq analysis. In total, 272 genes were regulated in V. parvula, including 39 genes in oxidoreductase processes. In S. gordonii, there was a high degree of inter-sample variation. Nevertheless, 69 genes were identified as potentially regulated by coaggregation, including two phosphotransferase system transporters and several other genes involved in carbohydrate metabolism. Overall, these data indicate that responses of V. parvula to coaggregation with S. gordonii are dominated by oxidative stress-related processes, whereas S. gordonii responses are more focussed on carbohydrate metabolism. We hypothesize that these responses may reflect changes in the local microenvironment in biofilms when S. gordonii or V. parvula immigrate into the system.
In Drosophila, protein trap strategies provide powerful approaches for the generation of tagged proteins expressed under endogenous control. Here, we describe expression and functional analysis to evaluate new Ubx and hth protein trap lines generated by the Cambridge Protein Trap project. Both protein traps exhibit spatial and temporal expression patterns consistent with the reported endogenous pattern in the embryo. In imaginal discs, Ubx-YFP is expressed throughout the haltere and 3rd leg imaginal discs, while Hth-YFP is expressed in the proximal regions of haltere and wing discs but not in the pouch region. The Ubx (CPTI000601) line is semilethal as a homozygote. No T3/A1 to T2 transformations were observed in the embryonic cuticle or the developing midgut. The homozygous survivors, however, exhibit a weak haltere phenotype with a few wing-like marginal bristles on the haltere capitellum. Although hth (CPTI000378) is completely lethal as a homozygote, the hth (CPTI000378) /hth (C1) genotype is viable. Using a hth deletion (Df(3R)BSC479) we show that hth (CPTI000378) /Df(3R)BSC479 adults are phenotypically normal. No transformations were observed in hth (CPTI000378), hth (CPTI000378) /hth (C1), or hth (CPTI000378) /Df(3R)BSC479 embryonic cuticles. We have successfully characterised the Ubx-YFP and Hth-YFP protein trap lines demonstrating that the tagged proteins show appropriate expression patterns and produce at least partially functional proteins.
To facilitate the ongoing research of Vibrio spp., a dedicated platform for the Vibrio research community is needed to host the fast-growing amount of genomic data and facilitate the analysis of these data. We present VibrioBase, a useful resource platform, providing all basic features of a sequence database with the addition of unique analysis tools which could be valuable for the Vibrio research community. VibrioBase currently houses a total of 252 Vibrio genomes developed in a user-friendly manner and useful to enable the analysis of these genomic data, particularly in the field of comparative genomics. Besides general data browsing features, VibrioBase offers analysis tools such as BLAST interfaces and JBrowse genome browser. Other important features of this platform include our newly developed in-house tools, the pairwise genome comparison (PGC) tool, and pathogenomics profiling tool (PathoProT). The PGC tool is useful in the identification and comparative analysis of two genomes, whereas PathoProT is designed for comparative pathogenomics analysis of Vibrio strains. Both of these tools will enable researchers with little experience in bioinformatics to get meaningful information from Vibrio genomes with ease. We have tested the validity and suitability of these tools and features for use in the next-generation database development.