Salmonella Phages Examined in the Electron Microscope

Ackermann, Hans-W.

doi:10.1007/978-1-59745-512-1_11

Cited by 16 publications

(14 citation statements)

References 40 publications

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“…E scherichia coli and S. enterica have significantly different distributions of phage genera ( P < 0.0001, χ 2 test), with the latter lacking Inoviruses, Epsilon15-like, Mu-like, and phiC31-like prophages. However, a wide diversity of viruses, including filamentous phages, were previously observed in Salmonella (Ackermann 2007), suggesting that a larger sampling will partially correct for this effect. The most noticeable difference between the species is the very high fraction of Lambda-like prophages in E. coli (50%) relative to S. enterica (23%) ( P < 10 −6 , χ 2 test).…”

Section: Resultsmentioning

confidence: 99%

The Adaptation of Temperate Bacteriophages to Their Host Genomes

Bobay

Rocha

Touchon

2012

Molecular Biology and Evolution

176

174

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Rapid turnover of mobile elements drives the plasticity of bacterial genomes. Integrated bacteriophages (prophages) encode host-adaptive traits and represent a sizable fraction of bacterial chromosomes. We hypothesized that natural selection shapes prophage integration patterns relative to the host genome organization. We tested this idea by detecting and studying 500 prophages of 69 strains of Escherichia and Salmonella. Phage integrases often target not only conserved genes but also intergenic positions, suggesting purifying selection for integration sites. Furthermore, most integration hotspots are conserved between the two host genera. Integration sites seem also selected at the large chromosomal scale, as they are nonrandomly organized in terms of the origin–terminus axis and the macrodomain structure. The genes of lambdoid prophages are systematically co-oriented with the bacterial replication fork and display the host high frequency of polarized FtsK-orienting polar sequences motifs required for chromosome segregation. matS motifs are strongly avoided by prophages suggesting counter selection of motifs disrupting macrodomains. These results show how natural selection for seamless integration of prophages in the chromosome shapes the evolution of the bacterium and the phage. First, integration sites are highly conserved for many millions of years favoring lysogeny over the lytic cycle for temperate phages. Second, the global distribution of prophages is intimately associated with the chromosome structure and the patterns of gene expression. Third, the phage endures selection for DNA motifs that pertain exclusively to the biology of the prophage in the bacterial chromosome. Understanding prophage genetic adaptation sheds new lights on the coexistence of horizontal transfer and organized bacterial genomes.

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Section: Resultsmentioning

confidence: 99%

The Adaptation of Temperate Bacteriophages to Their Host Genomes

Bobay

Rocha

Touchon

2012

Molecular Biology and Evolution

176

174

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“…As such, they were classified as ViI-like phages. Phages AYO111A, AYO145A, and AYO145B shared similar morphology, with the icosahedral heads of the former 2 being slightly smaller than the latter, resembling those of phage Felix O1, in which the head measured 73 nm in diameter and the noncontractile tail was 113 nm by 17 nm long (Ackermann 2007). Interestingly, Fig.…”

Section: Phage Morphologymentioning

confidence: 93%

Feces of feedlot cattle contain a diversity of bacteriophages that lyse non-O157 Shiga toxin-producing Escherichia coli

et al. 2015

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This study aimed to isolate and characterize bacteriophages that lyse non-O157 Shiga toxin-producing Escherichia coli (STEC) from cattle feces. Of 37 non-O157 STEC-infecting phages isolated, those targeting O26 (AXO26A, AYO26A, AYO26B), O103 (AXO103A, AYO103A), O111 (AXO111A, AYO111A), O121 (AXO121A, AXO121B), and O145 (AYO145A, AYO145B) were further characterized. Transmission electron microscopy showed that the 11 isolates belonged to 3 families and 6 genera: the families Myoviridae (types rV5, T4, ViI, O1), Siphoviridae (type T5), and Podoviridae (type T7). Genome size of the phages as determined by pulsed-field gel electrophoresis ranged from 38 to 177 kb. Excluding phages AXO26A, AYO103A, AYO145A, and AYO145B, all other phages were capable of lysing more than 1 clinically important strain from serogroups of O26, O91, O103, O111, O113, O121, and O128, but none exhibited infectivity across all serogroups. Moreover, phages AYO26A, AXO121A, and AXO121B were also able to lyse 4 common phage types of STEC O157:H7. Our findings show that a diversity of non-O157 STEC-infecting phages are harbored in bovine feces. Phages AYO26A, AYO26B, AXO103A, AXO111A, AYO111A, AXO121A, and AXO121B exhibited a broad host range against a number of serogroups of STEC and have potential for the biocontrol of STEC in the environment.

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“…Bringing Hans-Wolfgang Ackermann's [ 12 ] list of Salmonella phages observed by electron microscopy up to date, we now have almost 250 morphologically characterized viruses. Among the tailed viruses of the order Caudovirales [ 13 ] the breakdown is as follows: Myoviridae (phages with contractile tails), 64; Siphoviridae (viruses with long noncontractile tails), 94; and Podoviridae (short noncontractile tails), 71.…”

Section: Introductionmentioning

confidence: 99%

Salmonella Phages and Prophages: Genomics, Taxonomy, and Applied Aspects

Switt

Sulakvelidze

Wiedmann

et al. 2014

Methods in Molecular Biology

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Since this book was originally published in 2007 there has been a significant increase in the number of Salmonella bacteriophages, particularly lytic virus, and Salmonella strains which have been fully sequenced. In addition, new insights into phage taxonomy have resulted in new phage genera, some of which have been recognized by the International Committee of Taxonomy of Viruses (ICTV). The properties of each of these genera are discussed, along with the role of phage as agents of genetic exchange, as therapeutic agents, and their involvement in phage typing.

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Salmonella Phages Examined in the Electron Microscope

Cited by 16 publications

References 40 publications

The Adaptation of Temperate Bacteriophages to Their Host Genomes

The Adaptation of Temperate Bacteriophages to Their Host Genomes

Feces of feedlot cattle contain a diversity of bacteriophages that lyse non-O157 Shiga toxin-producing Escherichia coli

Salmonella Phages and Prophages: Genomics, Taxonomy, and Applied Aspects

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