-
Journal of Biomolecular Structure &... 2016Mycobacterium tuberculosis complex (MTBC) is notorious for causing diseases, such as tuberculosis. Tuberculosis caused by M. tuberculosis remains a global public health...
Mycobacterium tuberculosis complex (MTBC) is notorious for causing diseases, such as tuberculosis. Tuberculosis caused by M. tuberculosis remains a global public health concern. Two prophages, phiRv1 and phiRv2, can be found among most MTBC genomes. However, no precise functions have been assigned for the two prophages. In this paper, to find out the function of these two prophages, the distribution and function of phiRv1 and phiRv2 in MTBC genomes were analyzed from multiple omics data. We found that complex insertion, deletion, and reorganization appeared on the locus of two prophages in MTBC genomes; some genes of the two prophages can be translated and are functional from proteomic data; the expression of other prophage genes, such as Rv1577c, Rv2650c, Rv2652c, Rv2659c, and Rv2658c, can vary with environmental stresses and might enhance the fitness of MTBC. These data will facilitate our in-depth understanding of their function.
Topics: Gene Expression Regulation, Bacterial; Genome, Bacterial; Mycobacterium tuberculosis; Oxidative Phosphorylation; Prophages; Proteomics; Stress, Physiological; Transcriptome
PubMed: 25855385
DOI: 10.1080/07391102.2015.1022602 -
BMC Genomics Jun 2024Despite Spirochetales being a ubiquitous and medically important order of bacteria infecting both humans and animals, there is extremely limited information regarding...
BACKGROUND
Despite Spirochetales being a ubiquitous and medically important order of bacteria infecting both humans and animals, there is extremely limited information regarding their bacteriophages. Of the genus Treponema, there is just a single reported characterised prophage.
RESULTS
We applied a bioinformatic approach on 24 previously published Treponema genomes to identify and characterise putative treponemal prophages. Thirteen of the genomes did not contain any detectable prophage regions. The remaining eleven contained 38 prophage sequences, with between one and eight putative prophages in each bacterial genome. The prophage regions ranged from 12.4 to 75.1 kb, with between 27 and 171 protein coding sequences. Phylogenetic analysis revealed that 24 of the prophages formed three distinct sequence clusters, identifying putative myoviral and siphoviral morphology. ViPTree analysis demonstrated that the identified sequences were novel when compared to known double stranded DNA bacteriophage genomes.
CONCLUSIONS
In this study, we have started to address the knowledge gap on treponeme bacteriophages by characterising 38 prophage sequences in 24 treponeme genomes. Using bioinformatic approaches, we have been able to identify and compare the prophage-like elements with respect to other bacteriophages, their gene content, and their potential to be a functional and inducible bacteriophage, which in turn can help focus our attention on specific prophages to investigate further.
Topics: Prophages; Phylogeny; Treponema; Genomics; Genome, Bacterial; Computational Biology; Genome, Viral; Bacteriophages
PubMed: 38824509
DOI: 10.1186/s12864-024-10461-5 -
Journal of Theoretical Biology Dec 2019Lysogens are bacterial cells that have survived after genomically incorporating the DNA of temperate bacteriophages infecting them. If an infection results in lysogeny,...
Lysogens are bacterial cells that have survived after genomically incorporating the DNA of temperate bacteriophages infecting them. If an infection results in lysogeny, the lysogen continues to grow and divide normally, seemingly unaffected by the integrated viral genome known as a prophage. However, the prophage can still have an impact on the host's phenotype and overall fitness in certain environments. Additionally, the prophage within the lysogen can activate the lytic pathway via spontaneous prophage induction (SPI), killing the lysogen and releasing new progeny phages. These new phages can then lyse or lysogenize other susceptible nonlysogens, thereby impacting the competition between lysogens and nonlysogens. In a scenario with differing growth rates, it is not clear whether SPI would be beneficial or detrimental to the lysogens since it kills the host cell but also attacks nonlysogenic competitors, either lysing or lysogenizing them. Here we study the evolutionary dynamics of a mixture of lysogens and nonlysogens and derive general conditions on SPI rates for lysogens to displace nonlysogens. We show that there exists an optimal SPI rate for bacteriophage λ and explain why it is so low. We also investigate the impact of stochasticity and conclude that even at low cell numbers SPI can still provide an advantage to the lysogens. These results corroborate recent experimental studies showing that lower SPI rates are advantageous for phage-phage competition, and establish theoretical bounds on the SPI rate in terms of ecological and environmental variables associated with lysogens having a competitive advantage over their nonlysogenic counterparts.
Topics: Computer Simulation; Lysogeny; Models, Biological; Probability; Prophages; Stochastic Processes
PubMed: 31525321
DOI: 10.1016/j.jtbi.2019.110005 -
The Journal of General and Applied... Sep 2022Site-specific recombination (SSR) systems are employed in many genetic mobile elements, including temperate phages, for their integration and excision. Recently, they...
Site-specific recombination (SSR) systems are employed in many genetic mobile elements, including temperate phages, for their integration and excision. Recently, they have also been used as tools for applications in fields ranging from basic to synthetic biology. SPβ is a temperate phage of the Siphoviridae family found in the laboratory standard Bacillus subtilis strain 168. SPβ encodes a serine-type recombinase, SprA, and recombination directionality factor (RDF), SprB. SprA catalyzes recombination between the attachment site of the phage, attP, and that of the host, attB, to integrate phage genome into the attB site of the host genome and generate attL and attR at both ends of the prophage genome. SprB works in conjunction with SprA and switches from attB/attP to attL/R recombination, which leads to excision of the prophage. In the present study, we took advantage of this highly efficient recombination system to develop a site-specific integration and excision plasmid vector, named pSSβ. It was constructed using pUC plasmid and the SSR system components, attP, sprA and sprB of SPβ. pSSβ was integrated into the attB site with a significantly high efficiency, and the resulting pSSβ integrated strain also easily eliminated pSSβ itself from the host genome by the induction of SprB expression with xylose. This report presents two applications using pSSβ that are particularly suitable for gene complementation experiments and for a curing system of SPβ prophage, that may serve as a model system for the removal of prophages in other bacteria.
Topics: Bacillus subtilis; Bacteriophages; DNA; Integrases; Prophages; Recombination, Genetic
PubMed: 35387911
DOI: 10.2323/jgam.2021.10.004 -
Viruses May 2021Bacteriophages are natural biological entities that limit the growth and amplification of bacteria. They are important stimulators of evolutionary variability in... (Review)
Review
Bacteriophages are natural biological entities that limit the growth and amplification of bacteria. They are important stimulators of evolutionary variability in bacteria, and currently are considered a weapon against antibiotic resistance of bacteria. Nevertheless, apart from their antibacterial activity, phages may act as modulators of mammalian immune responses. In this paper, we focus on temperate phages able to execute the lysogenic development, which may shape animal or human immune response by influencing various processes, including phagocytosis of bacterial invaders and immune modulation of mammalian host cells.
Topics: Animals; Bacteriophages; Eukaryotic Cells; Host Microbial Interactions; Humans; Immunity; Immunomodulation; Lysogeny; Prophages
PubMed: 34071422
DOI: 10.3390/v13061013 -
BMC Microbiology Nov 2022Lactic acid bacteria (LAB) are used as starters in a wide variety of food fermentations. While the number of reports of phages infecting other LAB steadily increased...
BACKGROUND
Lactic acid bacteria (LAB) are used as starters in a wide variety of food fermentations. While the number of reports of phages infecting other LAB steadily increased over the years, information about phage associated with Latilactobacillus sakei, a frequently used meat starter, remains scarce.
RESULTS
In this study, a predictive genomic analysis of 43 Latilactobacillus sakei genomes revealed the presence of 26 intact, eleven questionable and 52 incomplete prophage sequences across all analysed genomes with a range of one to five predicted prophage sequences per strain. Screening 24 sakei strains for inducible prophages by utilising UV light or mitomycin C, we identified seven lysogenic strains showing lysis after induction during subsequent growth monitoring. Electron microscopic analysis revealed fully assembled virions in the purified lysates of four samples, thus confirming successful prophage induction. All virions featured icosahedral, isomeric heads and long, most likely non-contractile tails indicating siphoviruses. By performing phylogenetic analyses with various marker genes as well as full prophage sequences, we displayed a remarkably high diversity of prophages, that share a similar gene module organisation and six different chromosomal integration sites were identified. By sequencing viral DNA purified from lysates of Latilactobacillus sakei TMW 1.46, we demonstrate that simultaneous induction of multiple prophages is possible.
CONCLUSIONS
With this work, we not only provide data about the incidence of prophages harboured by the meat starter Latilactobacillus sakei, we also demonstrated their potential to impact growth of their host after induction, as well as forming seemingly fully assembled virions.
Topics: Prophages; Phylogeny; Genome, Bacterial; Lysogeny; Bacteriophages
PubMed: 36348293
DOI: 10.1186/s12866-022-02675-y -
Microbial Pathogenesis Apr 2022Vibrio species are geographically spread in marine habitats. Their virulence is often associated with the acquisition of mobile genetic elements such as phages. These... (Review)
Review
Vibrio species are geographically spread in marine habitats. Their virulence is often associated with the acquisition of mobile genetic elements such as phages. These phages can lysogenize the host cell by stably integrating their genomes into the host genome as prophages using the host or phage-encoded recombinases. Prophage-encoded virulence genes are then transferred to the host cell, which increases the population-level diversity and enhances bacterial survival. Prophages can also switch to a lytic cycle in response to environmental factors or host-quorum sensing. However, despite the importance of prophages as carriers of virulence factors, there are no reviews on the diversity and the lysis regulation of prophages in vibrios. Hence, the aim of this review was to highlight the pathogenicity of Vibrio's temperate phages, study their integration mechanisms, and their lysogeny regulation.
Topics: Bacteriophages; Lysogeny; Prophages; Vibrio; Virulence
PubMed: 35307601
DOI: 10.1016/j.micpath.2022.105490 -
Genes Feb 2022Whole-genome sequencing of a soil isolate , strain 7P, and its streptomycin-resistant derivative, 3-19, showed genome sizes of 3,609,117 bp and 3,609,444 bp,...
Whole-genome sequencing of a soil isolate , strain 7P, and its streptomycin-resistant derivative, 3-19, showed genome sizes of 3,609,117 bp and 3,609,444 bp, respectively. Annotation of the genome showed 3794 CDS (3204 with predicted function) and 3746 CDS (3173 with predicted function) in the genome of strains 7P and 3-19, respectively. In the genomes of both strains, the prophage regions Bp1 and Bp2 were identified. These include 52 ORF of prophage proteins in the Bp1 region and 38 prophages ORF in the Bp2 region. Interestingly, more than 50% of Bp1 prophage proteins are similar to the proteins of the in . The DNA region of Bp2 has 15% similarity to the DNA of the phage. Degradome analysis of the genome of both strains revealed 148 proteases of various classes. These include 60 serine proteases, 48 metalloproteases, 26 cysteine proteases, 4 aspartate proteases, 2 asparagine proteases, 3 threonine proteases, and 2 unclassified proteases. Likewise, three inhibitors of proteolytic enzymes were found. Comparative analysis of variants in the genomes of strains 7P and 3-19 showed the presence of 81 nucleotide variants in the genome 3-19. Among them, the missense mutations in the , , genes and in the upstream region of the gene were revealed. These nucleotide polymorphisms may have affected the streptomycin resistance and overproduction of extracellular hydrolases of the 3-19 strain. Finally, a plasmid DNA was found in strain 7P, which is lost in its derivative, strain 3-19. This plasmid contains five coding DNA sequencing (CDS), two regulatory proteins and three hypothetical proteins.
Topics: Bacillus pumilus; Nucleotides; Peptide Hydrolases; Prophages; Streptomycin
PubMed: 35327964
DOI: 10.3390/genes13030409 -
Virus Research Jan 2018A plethora of tools exist for identifying phage sequences in bacterial genomes, single cell amplified genomes, and host-associated and environmental metagenomes. Yet... (Review)
Review
A plethora of tools exist for identifying phage sequences in bacterial genomes, single cell amplified genomes, and host-associated and environmental metagenomes. Yet because the genetics of phages and their hosts are closely intertwined, distinguishing viral from bacterial signal remains an ongoing challenge. Further the size, quantity and fragmentary nature of modern 'omics datasets ushers in a new set of computational challenges. Here, we detail the promises and pitfalls of using currently available gene-centric or k-mer based tools for identifying prophage sequences in genomes and prophage and viral contigs in metagenomes. Each of these methods offers a unique piece of the puzzle to elucidating the intriguing signatures of phage-host coevolution.
Topics: Algorithms; Bacteria; Bacteriophages; Biological Coevolution; Computational Biology; Databases, Genetic; Datasets as Topic; Genome, Bacterial; Genome, Viral; Metagenomics; Prophages; Sequence Analysis, DNA; Sequence Analysis, RNA
PubMed: 29100906
DOI: 10.1016/j.virusres.2017.10.019 -
MBio Apr 2023Both temperate and obligately lytic phages have crucial roles in the biology of staphylococci. While superinfection exclusion among closely related temperate phages is a...
Both temperate and obligately lytic phages have crucial roles in the biology of staphylococci. While superinfection exclusion among closely related temperate phages is a well-characterized phenomenon, the interactions between temperate and lytic phages in staphylococci are not understood. Here, we present a resistance mechanism toward lytic phages of the genus , mediated by the membrane-anchored protein designated Pdp encoded by Staphylococcus aureus prophages, mostly of the Sa2 integrase type. The prophage accessory gene is strongly linked to the lytic genes for holin and ami2-type amidase and typically replaces genes for the toxin Panton-Valentine leukocidin (PVL). The predicted Pdp protein structure shows the presence of a membrane-binding α-helix in its N-terminal part and a cytoplasmic positively charged C terminus. We demonstrated that the mechanism of action of Pdp does not prevent the infecting kayvirus from adsorbing onto the host cell and delivering its genome into the cell, but phage DNA replication is halted. Changes in the cell membrane polarity and permeability were observed from 10 min after the infection, which led to prophage-activated cell death. Furthermore, we describe a mechanism of overcoming this resistance in a host-range mutant, which was selected on an S. aureus strain harboring prophage 53 encoding Pdp, and in which a chimeric gene product emerged via adaptive laboratory evolution. This first case of staphylococcal interfamily phage-phage competition is analogous to some other abortive infection defense systems and to systems based on membrane-destructive proteins. Prophages play an important role in virulence, pathogenesis, and host preference, as well as in horizontal gene transfer in staphylococci. In contrast, broad-host-range lytic staphylococcal kayviruses lyse most S. aureus strains, and scientists worldwide have come to believe that the use of such phages will be successful for treating and preventing bacterial diseases. The effectiveness of phage therapy is complicated by bacterial resistance, whose mechanisms related to therapeutic staphylococcal phages are not understood in detail. In this work, we describe a resistance mechanism targeting kayviruses that is encoded by a prophage. We conclude that the defense mechanism belongs to a broader group of abortive infections, which is characterized by suicidal behavior of infected cells that are unable to produce phage progeny, thus ensuring the survival of the host population. Since the majority of staphylococcal strains are lysogenic, our findings are relevant for the advancement of phage therapy.
Topics: Humans; Prophages; Staphylococcus aureus; Lysogeny; Staphylococcal Infections; Staphylococcus; Staphylococcus Phages; Membrane Proteins
PubMed: 36779718
DOI: 10.1128/mbio.02490-22