scholarly journals Analysis of metagenome-assembled viral genomes from the human gut reveals diverse putative CrAss-like phages with unique genomic features

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Natalya Yutin ◽  
Sean Benler ◽  
Sergei A. Shmakov ◽  
Yuri I. Wolf ◽  
Igor Tolstoy ◽  
...  
Keyword(s):  
Genomic Analysis ◽  
Comparative Genomic ◽  
Human Gut ◽  
Genomic Features ◽  
Viral Genomes ◽  
Founding Member ◽  
Phage Dna ◽  
Conserved Genes ◽  
Phage Genomics ◽  
Self Splicing

AbstractCrAssphage is the most abundant human-associated virus and the founding member of a large group of bacteriophages, discovered in animal-associated and environmental metagenomes, that infect bacteria of the phylum Bacteroidetes. We analyze 4907 Circular Metagenome Assembled Genomes (cMAGs) of putative viruses from human gut microbiomes and identify nearly 600 genomes of crAss-like phages that account for nearly 87% of the DNA reads mapped to these cMAGs. Phylogenetic analysis of conserved genes demonstrates the monophyly of crAss-like phages, a putative virus order, and of 5 branches, potential families within that order, two of which have not been identified previously. The phage genomes in one of these families are almost twofold larger than the crAssphage genome (145-192 kilobases), with high density of self-splicing introns and inteins. Many crAss-like phages encode suppressor tRNAs that enable read-through of UGA or UAG stop-codons, mostly, in late phage genes. A distinct feature of the crAss-like phages is the recurrent switch of the phage DNA polymerase type between A and B families. Thus, comparative genomic analysis of the expanded assemblage of crAss-like phages reveals aspects of genome architecture and expression as well as phage biology that were not apparent from the previous work on phage genomics.

scholarly journals Unique genomic features of crAss-like phages, the dominant component of the human gut virome

2020 ◽  
Author(s):  
Natalya Yutin ◽  
Sean Benler ◽  
Sergei A. Shmakov ◽  
Yuri I. Wolf ◽  
Igor Tolstoy ◽  
...  
Keyword(s):  
Defense Mechanism ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
New Order ◽  
Human Gut ◽  
Genomic Features ◽  
Dominant Component ◽  
Phage Dna ◽  
Conserved Genes ◽  
Self Splicing

AbstractCrAssphage is the most abundant virus identified in the human gut virome and the founding member of a large group of bacteriophages that infect bacteria of the phylum Bacteroidetes and have been discovered by metagenomics of both animal-associated and environmental habitats. By analysis of circular contigs from human gut microbiomes, we identified nearly 600 genomes of crAss-like phages. Phylogenetic analysis of conserved genes demonstrates the monophyly of crAss-like phages, which can be expected to become a new order of viruses, and of 5 distinct branches, likely, families within that order. Two of these putative families have not been identified previously. The phages in one of these groups have large genomes (145-192 kilobases) and contain an unprecedented high density of self-splicing introns and inteins. Many crAss-like phages encode suppressor tRNAs that enable readthrough of UGA or UAG stop-codons, mostly, in late phage genes, which could represent a distinct anti-defense strategy. Another putative anti-defense mechanism that might target an unknown defense system in Bacteroidetes inhibiting phage DNA replication involves multiple switches of the phage DNA polymerase type between A and B families. Thus, comparative genomic analysis of the expanded assemblage of crAss-like phages reveals several unusual features of genome architecture and expression as well as phage biology that were not apparent from the previous crAssphage analyses.

scholarly journals Evidence that Human Chlamydia pneumoniae Was Zoonotically Acquired

2009 ◽  
Vol 191 (23) ◽  
pp. 7225-7233 ◽  
Author(s):  
G. S. A. Myers ◽  
S. A. Mathews ◽  
M. Eppinger ◽  
C. Mitchell ◽  
K. K. O'Brien ◽  
...  
Keyword(s):  
Chlamydia Pneumoniae ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
Human Populations ◽  
Animal Reservoir ◽  
Single Nucleotide ◽  
Phascolarctos Cinereus ◽  
Zoonotic Infections ◽  
Conserved Genes ◽  
Animal Isolate

ABSTRACT Zoonotic infections are a growing threat to global health. Chlamydia pneumoniae is a major human pathogen that is widespread in human populations, causing acute respiratory disease, and has been associated with chronic disease. C. pneumoniae was first identified solely in human populations; however, its host range now includes other mammals, marsupials, amphibians, and reptiles. Australian koalas (Phascolarctos cinereus) are widely infected with two species of Chlamydia, C. pecorum and C. pneumoniae. Transmission of C. pneumoniae between animals and humans has not been reported; however, two other chlamydial species, C. psittaci and C. abortus, are known zoonotic pathogens. We have sequenced the 1,241,024-bp chromosome and a 7.5-kb cryptic chlamydial plasmid of the koala strain of C. pneumoniae (LPCoLN) using the whole-genome shotgun method. Comparative genomic analysis, including pseudogene and single-nucleotide polymorphism (SNP) distribution, and phylogenetic analysis of conserved genes and SNPs against the human isolates of C. pneumoniae show that the LPCoLN isolate is basal to human isolates. Thus, we propose based on compelling genomic and phylogenetic evidence that humans were originally infected zoonotically by an animal isolate(s) of C. pneumoniae which adapted to humans primarily through the processes of gene decay and plasmid loss, to the point where the animal reservoir is no longer required for transmission.

scholarly journals Characterization and genomic analysis of two Staphylococcus aureus bacteriophages isolated from poultry/livestock farms

2013 ◽  
Vol 94 (11) ◽  
pp. 2569-2576 ◽  
Author(s):  
Hyunjin Yoon ◽  
Jiae Yun ◽  
Jeong-A Lim ◽  
Eunjung Roh ◽  
Kyu-Seok Jung ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Host Range ◽  
Genomic Analysis ◽  
Enzyme Treatment ◽  
Comparative Genomic ◽  
The Family ◽  
Phage Dna ◽  
Host Range Determination ◽  
Range Determination ◽  
Livestock Farms

Staphylococcus aureus is one of the most important pathogens, causing various diseases in humans and animals. As methicillin-resistant S. aureus (MRSA) has become increasingly prevalent, controlling this pathogen with standard antibiotic treatment has become challenging. Bacteriophages (phages) have attracted interest as alternative antibacterial agents to control MRSA. In this study, we isolated six S. aureus phages from soils of poultry/livestock farms. Based on the results of host range determination with 150 S. aureus strains and restriction enzyme treatment of phage DNA, two phages, designated SP5 and SP6, were selected for further characterization and genome sequencing. Both SP5 and SP6 were classified as members of the family Siphoviridae. The genome of SP5 comprises 43 305 bp and contains 63 ORFs, while the SP6 genome comprises 42 902 bp and contains 61 ORFs. Although they have different host spectra, the phage genomes exhibit high nucleotide similarity to each other. Adsorption assay results suggested that the host range determinants of the two phages are involved in both adsorption and infection. Comparative genomic analyses of the two phages provided evidence that the lysogenic/lytic control module and tail proteins may be important for host specificity.

scholarly journals Diversity, evolution, and classification of virophages uncovered through global metagenomics

Microbiome ◽  
2019 ◽  
Vol 7 (1) ◽  
Author(s):  
David Paez-Espino ◽  
Jinglie Zhou ◽  
Simon Roux ◽  
Stephen Nayfach ◽  
Georgios A. Pavlopoulos ◽  
...  
Keyword(s):  
Genomic Analysis ◽  
Comparative Genomic ◽  
Human Gut ◽  
High Quality ◽  
Double Stranded Dna ◽  
Terrestrial Subsurface ◽  
Public Collection ◽  
Reference Genomes ◽  
Core Genes

Abstract Background Virophages are small viruses with double-stranded DNA genomes that replicate along with giant viruses and co-infect eukaryotic cells. Due to the paucity of virophage reference genomes, a collective understanding of the global virophage diversity, distribution, and evolution is lacking. Results Here we screened a public collection of over 14,000 metagenomes using the virophage-specific major capsid protein (MCP) as “bait.” We identified 44,221 assembled virophage sequences, of which 328 represent high-quality (complete or near-complete) genomes from diverse habitats including the human gut, plant rhizosphere, and terrestrial subsurface. Comparative genomic analysis confirmed the presence of four core genes in a conserved block. We used these genes to establish a revised virophage classification including 27 clades with consistent genome length, gene content, and habitat distribution. Moreover, for eight high-quality virophage genomes, we computationally predicted putative eukaryotic virus hosts. Conclusion Overall, our approach has increased the number of known virophage genomes by 10-fold and revealed patterns of genome evolution and global virophage distribution. We anticipate that the expanded diversity presented here will provide the backbone for further virophage studies.

Comparisons of classification methods for viral genomes and protein families using alignment-free vectorization

2018 ◽  
Vol 17 (4) ◽  
Author(s):  
Hsin-Hsiung Huang ◽  
Shuai Hao ◽  
Saul Alarcon ◽  
Jie Yang
Keyword(s):  
Discriminant Analysis ◽  
Linear Discriminant Analysis ◽  
Nearest Neighbor ◽  
Genomic Analysis ◽  
Support Vector ◽  
Comparative Genomic ◽  
Classification Methods ◽  
Statistical Classification ◽  
Linear Discriminant ◽  
Viral Genomes

Abstract In this paper, we propose a statistical classification method based on discriminant analysis using the first and second moments of positions of each nucleotide of the genome sequences as features, and compare its performances with other classification methods as well as natural vector for comparative genomic analysis. We examine the normality of the proposed features. The statistical classification models used including linear discriminant analysis, quadratic discriminant analysis, diagonal linear discriminant analysis, k-nearest-neighbor classifier, logistic regression, support vector machines, and classification trees. All these classifiers are tested on a viral genome dataset and a protein dataset for predicting viral Baltimore labels, viral family labels, and protein family labels.

scholarly journals Thousands of previously unknown phages discovered in whole-community human gut metagenomes

2021 ◽  
Author(s):  
Sean Benler ◽  
Natalya Yutin ◽  
Dmitry Antipov ◽  
Mikhail Raykov ◽  
Sergey Shmakov ◽  
...  
Keyword(s):  
Target Genes ◽  
Functional Characterization ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
Human Gut ◽  
Host Interactions ◽  
Family Protein ◽  
Host Cell Wall ◽  
Cellular Tolerance

Abstract Background: Double-stranded DNA bacteriophages (dsDNA phages) play pivotal roles in structuring human gut microbiomes; yet, the gut virome is far from being fully characterized, and additional groups of phages, including highly abundant ones, continue to be discovered by metagenome mining. A multilevel framework for taxonomic classification of viruses was recently adopted, facilitating the classification of phages into evolutionary informative taxonomic units based on hallmark genes. Together with advanced approaches for sequence assembly and powerful methods of sequence analysis, this revised framework offers the opportunity to discover and classify unknown phage taxa in the human gut.Results: A search of human gut metagenomes for circular contigs encoding phage hallmark genes resulted in the identification of 3,738 apparently complete phage genomes that represent 451 putative genera. Several of these phage genera are only distantly related to previously identified phages and are likely to found new families. Two of the candidate families, “Flandersviridae” and “Quimbyviridae”, include some of the most common and abundant members of the human gut virome that infect Bacteroides, Parabacteroides and Prevotella. The third proposed family, “Gratiaviridae”, consists of less abundant phages that are distantly related to the families Autographiviridae, Drexlerviridae and Chaseviridae. Analysis of CRISPR spacers indicates that phages of all three putative families infect bacteria of the phylum Bacteroidetes. Comparative genomic analysis of the three candidate phage families revealed features without precedent in phage genomes. Some “Quimbyviridae” phages possess Diversity-Generating Retroelements (DGRs) that generate hypervariable target genes nested within defense-related genes, whereas the previously known targets of phage-encoded DGRs are structural genes. Several “Flandersviridae” phages encode enzymes of the isoprenoid pathway, a lipid biosynthesis pathway that so far has not been known to be manipulated by phages. The “Gratiaviridae” phages encode a HipA-family protein kinase and glycosyltransferase, suggesting these phages modify the host cell wall, preventing superinfection by other phages. Hundreds of phages in these three and other families are shown to encode catalases and iron-sequestering enzymes that can be predicted to enhance cellular tolerance to reactive oxygen species.Conclusions: Analysis of phage genomes identified in whole-community human gut metagenomes resulted in the delineation of at least three new candidate families of Caudovirales and revealed diverse putative mechanisms underlying phage-host interactions in the human gut. Addition of these phylogenetically classified, diverse and distinct phages to public databases will facilitate taxonomic decomposition and functional characterization of human gut viromes.

scholarly journals Thousands of previously unknown phages discovered in whole-community human gut metagenomes

2020 ◽  
Author(s):  
Sean Benler ◽  
Natalya Yutin ◽  
Dmitry Antipov ◽  
Mikhail Raykov ◽  
Sergey Shmakov ◽  
...  
Keyword(s):  
Target Genes ◽  
Functional Characterization ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
Human Gut ◽  
Host Interactions ◽  
Family Protein ◽  
Host Cell Wall ◽  
Cellular Tolerance

AbstractBackgroundDouble-stranded DNA bacteriophages (dsDNA phages) play pivotal roles in structuring human gut microbiomes; yet, the gut phageome is far from being fully characterized, and additional groups of phages, including highly abundant ones, continue to be discovered by metagenome mining. A multilevel framework for taxonomic classification of viruses was recently adopted, facilitating the classification of phages into evolutionary informative taxonomic units based on hallmark genes. Together with advanced approaches for sequence assembly and powerful methods of sequence analysis, this revised framework offers the opportunity to discover and classify unknown phage taxa in the human gut.ResultsA search of human gut metagenomes for circular contigs encoding phage hallmark genes resulted in the identification of 3,738 apparently complete phage genomes that represent 451 putative genera. Several of these phage genera are only distantly related to previously identified phages and are likely to found new families. Two of the candidate families, “Flandersviridae” and “Quimbyviridae”, include some of the most common and abundant members of the human gut virome that infect Bacteroides, Parabacteroides and Prevotella. The third proposed family, “Gratiaviridae”, consists of less abundant phages that are distantly related to the families Autographiviridae, Drexlerviridae and Chaseviridae. Analysis of CRISPR spacers indicates that phages of all three putative families infect bacteria of the phylum Bacteroidetes. Comparative genomic analysis of the three candidate phage families revealed features without precedent in phage genomes. Some “Quimbyviridae” phages possess Diversity-Generating Retroelements (DGRs) that generate hypervariable target genes nested within defense-related genes, whereas the previously known targets of phage-encoded DGRs are structural genes. Several “Flandersviridae” phages encode enzymes of the isoprenoid pathway, a lipid biosynthesis pathway that so far has not been known to be manipulated by phages. The “Gratiaviridae” phages encode a HipA-family protein kinase and glycosyltransferase, suggesting these phages modify the host cell wall, preventing superinfection by other phages. Hundreds of phages in these three and other families are shown to encode catalases and iron-sequestering enzymes that can be predicted to enhance cellular tolerance to reactive oxygen species.ConclusionsAnalysis of phage genomes identified in whole-community human gut metagenomes resulted in the delineation of at least three new candidate families of Caudovirales and revealed diverse putative mechanisms underlying phage-host interactions in the human gut. Addition of these phylogenetically classified, diverse and distinct phages to public databases will facilitate taxonomic decomposition and functional characterization of human gut viromes.

scholarly journals Comparative Genomic Analysis of the Biotechnological Potential of the Novel Species Pseudomonas wadenswilerensis CCOS 864T and Pseudomonas reidholzensis CCOS 865T

Diversity ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 204
Author(s):  
Dominik Rutz ◽  
David Frasson ◽  
Martin Sievers ◽  
Jochen Blom ◽  
Fabio Rezzonico ◽  
...  
Keyword(s):  
New Species ◽  
Plant Pathogens ◽  
Draft Genome ◽  
Genomic Analysis ◽  
Yield Potential ◽  
Comparative Genomic ◽  
Genomic Features ◽  
Two New Species ◽  
Genes Encoding ◽  
Potential Applications

In recent years, the use of whole-cell biocatalysts and biocatalytic enzymes in biotechnological applications originating from the genus Pseudomonas has greatly increased. In 2014, two new species within the Pseudomonas putida group were isolated from Swiss forest soil. In this study, the high quality draft genome sequences of Pseudomonas wadenswilerensis CCOS 864T and Pseudomonas reidholzensis CCOS 865T were used in a comparative genomics approach to identify genomic features that either differed between these two new species or to selected members of the P. putida group. The genomes of P. wadenswilerensis CCOS 864T and P. reidholzensis CCOS 865T were found to share genomic features for the degradation of aromatic compounds or the synthesis of secondary metabolites. In particular, genes encoding for biocatalytic relevant enzymes belonging to the class of oxidoreductases, proteases and isomerases were found, that could yield potential applications in biotechnology. Ecologically relevant features revealed that both species are probably playing an important role in the degradation of soil organic material, the accumulation of phosphate and biocontrol against plant pathogens.

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