Inactivation of Coliphage T2H by Basic Amino Acids

Watanabe, Takashi; Saito, Hajime

doi:10.1111/j.1348-0421.1978.tb00360.x

Cited by 3 publications

(3 citation statements)

References 15 publications

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“…We also see upregulation of the V. cholerae -inducible lysine decarboxylase ( Table S1 , Tab 2), and in at least one bacterial system, a lysine decarboxylase is able to use ornithine as a substrate ( 42 ). Alternatively, arginine has been found to have a deactivating effect on phage virions under certain conditions ( 43 – 45 ), and so the upregulation of arginine may be an attempt by the host cell to curb phage production.…”

Section: Resultsmentioning

confidence: 99%

A Family of Viral Satellites Manipulates Invading Virus Gene Expression and Can Affect Cholera Toxin Mobilization

et al. 2020

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Many viruses possess temporally unfolding gene expression patterns aimed at subverting host defenses, commandeering host metabolism, and ultimately producing a large number of progeny virions. High-throughput omics tools, such as RNA sequencing (RNA-seq), have dramatically enhanced the resolution of expression patterns during infection. Less studied have been viral satellites, mobile genomes that parasitize viruses. By performing RNA-seq on infection time courses, we have obtained the first time-resolved transcriptomes for bacteriophage satellites during lytic infection. Specifically, we have acquired transcriptomes for the lytic Vibrio cholerae phage ICP1 and all five known variants of ICP1’s parasite, the phage inducible chromosomal island-like elements (PLEs). PLEs rely on ICP1 for both DNA replication and mobilization and abolish production of ICP1 progeny in infected cells. We investigated PLEs’ impact on ICP1 gene expression and found that PLEs did not broadly restrict or reduce ICP1 gene expression. A major exception occurred in ICP1’s capsid morphogenesis operon, which was downregulated by each of the PLE variants. Surprisingly, PLEs were also found to alter the gene expression of CTXΦ, the integrative phage that encodes cholera toxin and is necessary for virulence of toxigenic V. cholerae. One PLE, PLE1, upregulated CTXΦ genes involved in replication and integration and boosted CTXΦ mobility following induction of the SOS response. IMPORTANCE Viral satellites are found in all domains of life and can have profound fitness effects on both the viruses they parasitize and the cells they reside in. In this study, we have acquired the first RNA sequencing (RNA-seq) transcriptomes of viral satellites outside plants, as well as the transcriptome of the phage ICP1, a predominant predator of pandemic Vibrio cholerae. Capsid downregulation, previously observed in an unrelated phage satellite, is conserved among phage inducible chromosomal island-like elements (PLEs), suggesting that viral satellites are under strong selective pressure to reduce the capsid expression of their larger host viruses. Despite conserved manipulation of capsid expression, PLEs exhibit divergent effects on CTXΦ transcription and mobility. Our results demonstrate that PLEs can influence both their hosts’ resistance to phage and the mobility of virulence-encoding elements, suggesting that PLEs can play a substantial role in shaping Vibrio cholerae evolution.

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Section: Resultsmentioning

confidence: 99%

A Family of Viral Satellites Manipulates Invading Virus Gene Expression and Can Affect Cholera Toxin Mobilization

et al. 2020

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“…Alternatively, arginine has been found to have a deactivating effect on phage virions under certain conditions [39][40][41], so the upregulation of arginine may be an attempt by the host cell to curb phage production.…”

Section: Introductionmentioning

confidence: 99%

A family of viral satellites manipulates invading virus gene expression and affects cholera toxin mobilization

Barth

Netter

Angermeyer

et al. 2020

Preprint

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Many viruses possess temporally unfolding gene expression patterns aimed at subverting host defenses, commandeering host metabolism, and ultimately producing a large number of progeny virions. High throughput -omics tools, such as RNA-seq, have dramatically enhanced resolution of expression patterns during infection. Less studied have been viral satellites, mobile genomes that parasitize viruses and have far reaching effects on host-cell fitness. By performing RNA-seq on infection time courses, we have obtained the first time-resolved transcriptomes for bacteriophage satellites during lytic infection. Specifically, we have acquired transcriptomes for the lytic Vibrio cholerae phage ICP1 and all five known variants of ICP1's parasite, the Phage Inducible Chromosomal Island-Like Elements (PLEs). PLEs rely on ICP1 for both DNA replication and mobilization, and abolish production of ICP1 progeny in infected cells. We investigated PLEs impact on ICP1 gene expression and found that PLEs did not broadly restrict or reduce ICP1 gene expression. A major exception occurred in ICP1's capsid morphogenesis operon, which was downregulated by each of the PLE variants. This transcriptional manipulation, conserved among PLEs, has also evolved independently in at least one other phage satellite, suggesting that viral satellites may be under strong selective pressure to reduce the capsid expression of their larger host viruses. Surprisingly, PLEs were also found to alter the gene expression of CTXφ, the integrative phage that encodes cholera toxin and is necessary for virulence of toxigenic V. cholerae. One PLE, PLE1, upregulated CTXφ genes involved in replication and integration, and boosted CTXφ mobility following induction of the SOS response. Our data show that PLEs exhibit conserved manipulation of their host-phage's gene expression, but divergent effects on CTXφ, revealing that PLEs can influence both their hosts' resistance to phage and the mobility of virulence encoding elements.So far, few insights have been gained into the gene expression programs of ICP1 and PLEs. PLE1 expresses its integrase in uninfected cells [22], expression of PLE1's replication initiator, RepA, is induced following infection of ICP1 [23], and the PLE's lysis modulator, LidI, is detectable by Western blot late during ICP1 infection [25]. The PLE integrase's recombination directionality factor (necessary for directing integrase excision activity) is PexA, an ICP1 protein whose native function is unknown, but whose expression can be detected by 5 minutes post infection [22]. While these limited observations have provided insight into key PLE and ICP1 genes, the gross expression patterns of ICP1 and PLEs remain unknown. Until now, we have not known the degree to which ICP1 alters cellular expression patterns, and whether PLEs alter ICP1's gene expression or reproduce and restrict ICP1 without such alterations. To address these questions, we performed RNA-seq on V. cholerae infected by ICP1 over the course of the infection cycle. We sequenced the transc...

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“…The phagocidal effect of lysine could have its cause in interactions of the &-amino groups of lysine (in the phage-inactivating arginine the guanido group) with phosphate residues of phage DNA [132, 1331. It is also supposed that basic amino acids bind to the phage tails, resulting in conformational changes of the tail structure[134]. In this connection it is interesting t o note that &-poly-L-lysine, produced by Streptmyces albulus, also display phagocidal activity [ 1351.Of the phage-bacterium interactions the adsorption of phages on the cell surface, initiating the infection process, represents a preferred point from which to attack the desired obviation of a phage multiplication.…”

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confidence: 99%

Importance of bacteriophages in fermentation processes

Wünsche

1989

Acta Biotechnologica

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Any bacterial strain can be infected by virulent phages or harbour one or more prophages. Therefore, bacteria-phage interactions are to be regarded as fundamental properties of bacteria. In current industrial fermentation processes phages can be advantageously employed for the identification of bacterial production strains (phage typing). In some cases phages are involved in the production of enzymes and special substances. The fundamental importance of phages in any technical fermentation process, however, is based on the peculiarities of their obligately parasitic life cycle. The propagation of phages in fermentation processes can cause complete (or a t least partial) lysis of the production strains and, consequently, serious disturbances in the production process and considerable economic losses. The phage problem in the fermentation industry has not yet been completely solved. For the protection of technical processes against virulent phages five measures are discussed: phage-protected sterile fermentation, employment. of alternative cultures, employment of phage-resistant mutants. employment of phage inhibitors, and employment of immobilized bacterial cells. The problem of the protection of bacterial production strains from prophage induction is more difficult and practically unsolved. Two possibilities to minimize the process risk due to temperate phages, the elimination of inducing factors during the fermentation process, and the selection of production strains which are difficult to induce, are discussed.

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Inactivation of Coliphage T2H by Basic Amino Acids

Cited by 3 publications

References 15 publications

A Family of Viral Satellites Manipulates Invading Virus Gene Expression and Can Affect Cholera Toxin Mobilization

A Family of Viral Satellites Manipulates Invading Virus Gene Expression and Can Affect Cholera Toxin Mobilization

A family of viral satellites manipulates invading virus gene expression and affects cholera toxin mobilization

Importance of bacteriophages in fermentation processes

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