scholarly journals Comparative Genomic Analysis of Mycobacteriaceae Reveals Horizontal Gene Transfer-Mediated Evolution of the CRISPR-Cas System in the Mycobacterium tuberculosis Complex

mSystems ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Anoop Singh ◽  
Mohita Gaur ◽  
Vishal Sharma ◽  
Palak Khanna ◽  
Ankur Bothra ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Common Ancestor ◽  
Genomic Analysis ◽  
Comparative Genomic Analysis ◽  
Comparative Genomic ◽  
Last Common Ancestor ◽  
Content Type ◽  
Type Iii

ABSTRACT Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) genes are conserved genetic elements in many prokaryotes, including Mycobacterium tuberculosis, the causative agent of tuberculosis. Although knowledge of CRISPR locus variability has been utilized in M. tuberculosis strain genotyping, its evolutionary path in Mycobacteriaceae is not well understood. In this study, we have performed a comparative analysis of 141 mycobacterial genomes and identified the exclusive presence of the CRISPR-Cas type III-A system in M. tuberculosis complex (MTBC). Our global phylogenetic analysis of CRISPR repeats and Cas10 proteins offers evidence of horizontal gene transfer (HGT) of the CRISPR-Cas module in the last common ancestor of MTBC and Mycobacterium canettii from a Streptococcus-like environmental bacterium. Additionally, our results show that the variation of CRISPR-Cas organization in M. tuberculosis lineages, especially in the Beijing sublineage of lineage 2, is due to the transposition of insertion sequence IS6110. The direct repeat (DR) region of the CRISPR-Cas locus acts as a hot spot for IS6110 insertion. We show in M. tuberculosis H37Rv that the repeat at the 5′ end of CRISPR1 of the forward strand is an atypical repeat made up partly of IS-terminal inverted repeat and partly CRISPR DR. By tracing an undetectable spacer sequence in the DR region, the two CRISPR loci could theoretically be joined to reconstruct the ancestral single CRISPR-Cas locus organization, as seen in M. canettii. This study retracing the evolutionary events of HGT and IS6110-driven genomic deletions helps us to better understand the strain-specific variations in M. tuberculosis lineages. IMPORTANCE Comparative genomic analysis of prokaryotes has led to a better understanding of the biology of several pathogenic microorganisms. One such clinically important pathogen is M. tuberculosis, the leading cause of bacterial infection worldwide. Recent evidence on the functionality of the CRISPR-Cas system in M. tuberculosis has brought back focus on these conserved genetic elements, present in many prokaryotes. Our study advances understanding of mycobacterial CRISPR-Cas origin and its diversity among the different species. We provide phylogenetic evidence of acquisition of CRISPR-Cas type III-A in the last common ancestor shared between MTBC and M. canettii, by HGT-mediated events. The most likely source of HGT was an environmental Firmicutes bacterium. Genomic mapping of the CRISPR loci showed the IS6110 transposition-driven variations in M. tuberculosis strains. Thus, this study offers insights into events related to the evolution of CRISPR-Cas in M. tuberculosis lineages.

scholarly journals Comparative Genomic Analysis of Closely Related Acetobacter pasteurianus Strains Provides Evidence of Horizontal Gene Transfer and Reveals Factors Necessary for Thermotolerance

2020 ◽  
Vol 202 (8) ◽  
Author(s):  
Minenosuke Matsutani ◽  
Nami Matsumoto ◽  
Hideki Hirakawa ◽  
Yuh Shiwa ◽  
Hirofumi Yoshikawa ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Genomic Analysis ◽  
Comparative Genomic Analysis ◽  
Comparative Genomic ◽  
Gene Repertoire ◽  
Content Type ◽  
Acetobacter Pasteurianus ◽  
Respiratory Chains

ABSTRACT Acetobacter pasteurianus is an industrial strain used for the vinegar production. Many A. pasteurianus strains with different phenotypic characteristics have been isolated so far. To understand the genetic background underpinning these phenotypes, a comparative genomic analysis of A. pasteurianus strains was conducted. Based on bioinformatics and experimental results, we report the following. (i) The gene repertoire related to the respiratory chains showed that several horizontal gene transfer events occurred after the divergence of these strains, indicating that the respiratory chain in A. pasteurianus has the diversity to adapt to its environment. (ii) There is a clear difference in thermotolerance even between 12 closely related strains. NBRC 3279, NBRC 3284, and NBRC 3283, in particular, which have only 55 mutations in total, showed differences in thermotolerance. The Na+/H+ antiporter gene nhaK2 was mutated in the thermosensitive NBRC 3279 and NBRC 3284 strains and not in the thermotolerant NBRC 3283 strain. The Na+/H+ antiporter activity of the three strains and expression of nhaK2 gene from NBRC 3283 in the two thermosensitive strains showed that these mutations are critical for thermotolerance. These results suggested that horizontal gene transfer events and several mutations have affected the phenotypes of these closely related strains. IMPORTANCE Acetobacter pasteurianus, an industrial vinegar-producing strain, exhibits diverse phenotypic differences such as respiratory activity related to acetic acid production, acetic acid resistance, or thermotolerance. In this study, we investigated the correlations between genome sequences and phenotypes among closely related A. pasteurianus strains. The gene repertoire related to the respiratory chains showed that the respiratory components of A. pasteurianus has a diversity caused by several horizontal gene transfers and mutations. In three closely related strains with clear differences in their thermotolerances, we found that the insertion or deletion that occurred in the Na+/H+ antiporter gene nhaK2 is directly related to their thermotolerance. Our study suggests that a relatively quick mutation has occurred in the closely related A. pasteurianus due to its genetic instability and that this has largely affected its phenotype.

scholarly journals Horizontal Gene Transfer Clarifies Taxonomic Confusion and Promotes the Genetic Diversity and Pathogenicity of Plesiomonas shigelloides

mSystems ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Zhiqiu Yin ◽  
Si Zhang ◽  
Yi Wei ◽  
Meng Wang ◽  
Shuangshuang Ma ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Evolutionary Dynamics ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
Content Type ◽  
Pan Genome ◽  
Long Time ◽  
Taxonomic Confusion

The taxonomic position of P. shigelloides has been the subject of debate for a long time, and until now, the evolutionary dynamics and pathogenesis of P. shigelloides were unclear. In this study, pan-genome analysis indicated extensive genetic diversity and the presence of large and variable gene repertoires. Our results revealed that horizontal gene transfer was the focal driving force for the genetic diversity of the P. shigelloides pan-genome and might have contributed to the emergence of novel properties. Vibrionaceae and Aeromonadaceae were found to be the predominant donor taxa for horizontal genes, which might have caused the taxonomic confusion historically. Comparative genomic analysis revealed the potential of P. shigelloides to cause intestinal and invasive diseases. Our results could advance the understanding of the evolution and pathogenesis of P. shigelloides, particularly in elucidating the role of horizontal gene transfer and investigating virulence-related elements.

scholarly journals An Evolutionary Link between Natural Transformation and CRISPR Adaptive Immunity

mBio ◽  
2012 ◽  
Vol 3 (5) ◽  
Author(s):  
Peter Jorth ◽  
Marvin Whiteley
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Bacterial Diversity ◽  
Natural Transformation ◽  
Bacterial Species ◽  
Comparative Genomic ◽  
Content Type ◽  
Immune Systems ◽  
Adaptive Immune ◽  
Adaptive Immune Systems

ABSTRACTNatural transformation by competent bacteria is a primary means of horizontal gene transfer; however, evidence that competence drives bacterial diversity and evolution has remained elusive. To test this theory, we used a retrospective comparative genomic approach to analyze the evolutionary history ofAggregatibacter actinomycetemcomitans, a bacterial species with both competent and noncompetent sister strains. Through comparative genomic analyses, we reveal that competence is evolutionarily linked to genomic diversity and speciation. Competence loss occurs frequently during evolution and is followed by the loss of clustered regularly interspaced short palindromic repeats (CRISPRs), bacterial adaptive immune systems that protect against parasitic DNA. Relative to noncompetent strains, competent bacteria have larger genomes containing multiple rearrangements. In contrast, noncompetent bacterial genomes are extremely stable but paradoxically susceptible to infective DNA elements, which contribute to noncompetent strain genetic diversity. Moreover, incomplete noncompetent strain CRISPR immune systems are enriched for self-targeting elements, which suggests that the CRISPRs have been co-opted for bacterial gene regulation, similar to eukaryotic microRNAs derived from the antiviral RNA interference pathway.IMPORTANCEThe human microbiome is rich with thousands of diverse bacterial species. One mechanism driving this diversity is horizontal gene transfer by natural transformation, whereby naturally competent bacteria take up environmental DNA and incorporate new genes into their genomes. Competence is theorized to accelerate evolution; however, attempts to test this theory have proved difficult. Through genetic analyses of the human periodontal pathogenAggregatibacter actinomycetemcomitans, we have discovered an evolutionary connection between competence systems promoting gene acquisition and CRISPRs (clustered regularly interspaced short palindromic repeats), adaptive immune systems that protect bacteria against genetic parasites. We show that competentA. actinomycetemcomitansstrains have numerous redundant CRISPR immune systems, while noncompetent bacteria have lost their CRISPR immune systems because of inactivating mutations. Together, the evolutionary data linking the evolution of competence and CRISPRs reveals unique mechanisms promoting genetic heterogeneity and the rise of new bacterial species, providing insight into complex mechanisms underlying bacterial diversity in the human body.

scholarly journals The Complete Genome of the Atypical Enteropathogenic Escherichia coli Archetype Isolate E110019 Highlights a Role for Plasmids in Dissemination of the Type III Secreted Effector EspT

2019 ◽  
Vol 87 (10) ◽  
Author(s):  
Tracy H. Hazen ◽  
David A. Rasko
Keyword(s):  
Escherichia Coli ◽  
Complete Genome ◽  
Genomic Analysis ◽  
Host Cells ◽  
Comparative Genomic ◽  
Content Type ◽  
E Coli ◽  
Type Iii ◽  
Severe Diarrhea ◽  
Typical Epec

ABSTRACT Enteropathogenic Escherichia coli (EPEC) is a leading cause of moderate to severe diarrhea among young children in developing countries, and EPEC isolates can be subdivided into two groups. Typical EPEC (tEPEC) bacteria are characterized by the presence of both the locus of enterocyte effacement (LEE) and the plasmid-encoded bundle-forming pilus (BFP), which are involved in adherence and translocation of type III effectors into the host cells. Atypical EPEC (aEPEC) bacteria also contain the LEE but lack the BFP. In the current report, we describe the complete genome of outbreak-associated aEPEC isolate E110019, which carries four plasmids. Comparative genomic analysis demonstrated that the type III secreted effector EspT gene, an autotransporter gene, a hemolysin gene, and putative fimbrial genes are all carried on plasmids. Further investigation of 65 espT-containing E. coli genomes demonstrated that different espT alleles are associated with multiple plasmids that differ in their overall gene content from the E110019 espT-containing plasmid. EspT has been previously described with respect to its role in the ability of E110019 to invade host cells. While other type III secreted effectors of E. coli have been identified on insertion elements and prophages of the chromosome, we demonstrated in the current study that the espT gene is located on multiple unique plasmids. These findings highlight a role of plasmids in dissemination of a unique E. coli type III secreted effector that is involved in host invasion and severe diarrheal illness.

Comparative genomic analysis of Mycobacterium tuberculosis Beijing-like strains revealed specific genetic variations associated with virulence and drug resistance

2017 ◽  
Vol 54 ◽  
pp. 314-323 ◽  
Author(s):  
Juan Germán Rodríguez-Castillo ◽  
Camilo Pino ◽  
Luis Fernando Niño ◽  
Juan Carlos Rozo ◽  
Claudia Llerena-Polo ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Genomic Analysis ◽  
Genetic Variations ◽  
Comparative Genomic Analysis ◽  
Comparative Genomic

scholarly journals Comparative Genomic Analysis Provides Insights into the Evolution and Genetic Diversity of Community-Genotype Sequence Type 72 Staphylococcus aureus Isolates

mSystems ◽  
2021 ◽  
Author(s):  
Wangxiao Zhou ◽  
Ye Jin ◽  
Yanzi Zhou ◽  
Yuan Wang ◽  
Luying Xiong ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Staphylococcus Aureus ◽  
Genomic Analysis ◽  
Comparative Genomic Analysis ◽  
Sequence Type ◽  
Comparative Genomic ◽  
Health Issues ◽  
Content Type ◽  
Genome Wide Analysis ◽  
Genome Wide

Understanding the evolution and dissemination of community-genotype ST72 Staphylococcus aureus isolates is important, as isolates of this lineage have rapidly spread into hospital settings and caused serious health issues. In this study, we first carried out genome-wide analysis of 107 global ST72 isolates to characterize the evolution and genetic diversity of the ST72 lineage.

scholarly journals Draft Genome Sequence of Listeria monocytogenes CIIMS-NV-3, a Strain Isolated from Vaginal Discharge of a Woman from Central India

2019 ◽  
Vol 8 (6) ◽  
Author(s):  
Pooja M. Kishnani ◽  
Nitin V. Kurkure ◽  
Sukhadeo B. Barbuddhe ◽  
Swapnil P. Doijad ◽  
Trinad Chakraborty ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Genome Sequence ◽  
Draft Genome ◽  
Genomic Analysis ◽  
Central India ◽  
Vaginal Swab ◽  
Comparative Genomic Analysis ◽  
Draft Genome Sequence ◽  
Comparative Genomic ◽  
Content Type

We present here the draft genome sequence of Listeria monocytogenes CIIMS-NV-3, a serovar 4b strain isolated from the vaginal swab of a female patient from central India. The availability of this genome may provide useful information on virulence characteristics for comparative genomic analysis.

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