Gene transfer agents, bacteriophages, and bacteriocins of Rhodopseudomonas capsulata

Wall, Judy D.; Weaver, Paul F.; Gest, Howard

doi:10.1007/bf00447140

Cited by 118 publications

(74 citation statements)

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“…The defective prophages of R. capsulatus and Methanococcus voltae resemble small bacteriophages, package short (4.4-to 4.5-kb) random segments of their host bacterial DNAs, and perform generalized transduction (3,16,32,37,56). The characteristics of VSH-1 and the well-studied GTA from R. capsulatus are compared in Table 2.…”

Section: Discussionmentioning

confidence: 99%

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Identification of Genes of VSH-1, a Prophage-Like Gene Transfer Agent of Brachyspira hyodysenteriae

et al. 2005

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VSH-1 is a mitomycin C-inducible prophage of the anaerobic spirochete Brachyspira hyodysenteriae. Purified VSH-1 virions are noninfectious, contain random 7.5-kb fragments of the bacterial genome, and mediate generalized transduction of B. hyodysenteriae cells. In order to identify and sequence genes of this novel gene transfer agent (GTA), proteins associated either with VSH-1 capsids or with tails were purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The N-terminal amino acid sequences of 11 proteins were determined. Degenerate PCR primers were designed from the amino acid sequences and used to amplify several VSH-1 genes from B. hyodysenteriae strain B204 DNA. A clone library of B. hyodysenteriae B204 DNA was subsequently screened by Southern hybridization methods and used to identify and sequence overlapping DNA inserts containing additional VSH-1 genes. VSH-1 genes spanned 16.3 kb of the B. hyodysenteriae Brachyspira hyodysenteriae is an anaerobic spirochete and the etiologic agent of swine dysentery, a severe, mucohemorrhagic intestinal disease afflicting animals in the postweaning period of growth (20). B. hyodysenteriae cells contain a defective prophage, VSH-1, which is induced when mitomycin C is added to cultures of growing cells (27). This prophage has been purified and characterized previously (28). VSH-1 particles resemble virions in morphology but, with a head diameter of 45 nm and a tail length of 64 nm, are substantially smaller.VSH-1 virions contain random 7.5-kb fragments of host genomic DNA (28), making it difficult to identify VSH-1 genes. Purified virions are "noninfectious," that is, they do not lyse spirochete cells when added to cultures of B. hyodysenteriae or of other Brachyspira species. VSH-1 transfers bacterial genes between B. hyodysenteriae cells (28, 52) and has likely contributed to the recombinant population structure of B. hyodysenteriae (55). This generalized transduction activity of VSH-1 is useful for constructing B. hyodysenteriae mutant strains (35).VSH-1 is the first natural gene transfer mechanism to be described for a spirochete.The ability to recognize VSH-1-specific genes would be a major advance for investigating intracellular and intercellular activities of VSH-1 and for evaluating its ecological significance to its host bacterium. To overcome the inability to identify distinct VSH-1 genes carried by virions, structural protein genes were identified from the sequences of VSH-1 head and tail proteins. Genes for endolysin and holin proteins, proteins enabling the release of bacteriophage from bacterial cells, were discovered during nucleotide sequence analyses. Recombinant endolysin was shown to degrade peptidoglycan. Based on its genome and biological properties, VSH-1 resembles prophagelike gene transfer agents (GTA) reported for other bacteria (3,32,37,46,56). MATERIALS AND METHODSSeparation of VSH-1 whole virions and tailless heads. VSH-1 particles were harvested from B. hyodysenteriae strain B204 cultures (400 ml) in NT broth 7 to 8 h after...

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Section: Discussionmentioning

confidence: 99%

“…Recombinant endolysin was shown to degrade peptidoglycan. Based on its genome and biological properties, VSH-1 resembles prophagelike gene transfer agents (GTA) reported for other bacteria (3,32,37,46,56). …”

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confidence: 99%

Identification of Genes of VSH-1, a Prophage-Like Gene Transfer Agent of Brachyspira hyodysenteriae

et al. 2005

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“…The plasmids and strains used are listed in Table 1. R. capsulatus cultures were grown aerobically or phototrophically in either yeast extract-peptone-salts (YPS) (44) or RCV minimal medium (2) at 30°C. P. denitrificans was grown aerobically in Sistrom's succinic acid minimal medium A (SIS) (4) or Luria broth (LB) (33) at 30°C.…”

Section: Methodsmentioning

confidence: 99%

Long-Chain Acyl-Homoserine Lactone Quorum-Sensing Regulation of Rhodobacter capsulatus Gene Transfer Agent Production

et al. 2002

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Many proteobacteria use acyl-homoserine lactones as quorum-sensing signals. Traditionally, biological detection systems have been used to identify bacteria that produce acyl-homoserine lactones, although the specificities of these detection systems can limit discovery. We used a sensitive approach that did not require a bioassay to detect production of long-acyl-chain homoserine lactone production by Rhodobacter capsulatus and Paracoccus denitrificans. These long-chain acyl-homoserine lactones are not readily detected by standard bioassays. The most abundant acyl-homoserine lactone was N-hexadecanoyl-homoserine lactone. The longchain acyl-homoserine lactones were concentrated in cells but were also found in the culture fluid. An R. capsulatus gene responsible for long-chain acyl-homoserine lactone synthesis was identified. A mutation in this gene, which we named gtaI, resulted in decreased production of the R. capsulatus gene transfer agent, and gene transfer agent production was restored by exogenous addition of N-hexadecanoyl-homoserine lactone. Thus, long-chain acyl-homoserine lactones serve as quorum-sensing signals to enhance genetic exchange in R. capsulatus.Many proteobacteria use acyl-homoserine lactone (acyl-HSL) signals in cell density-dependent gene regulation (9,11,45). Acyl-HSLs act as intercellular signals that allow bacterial species to monitor their population density and activate specific sets of genes at high cell densities. This type of cell density-dependent gene regulation, also called quorum sensing, was first described in the marine bacterium Vibrio fischeri (6, 21), which uses an acyl-HSL to activate luminescence gene expression. The V. fischeri quorum-sensing regulatory elements are LuxI and LuxR (8). The LuxI protein is the acyl-HSL synthase responsible for production of the N-3-oxohexanoyl-HSL. LuxR is a transcription factor that activates luminescence gene expression when bound by the acyl-HSL signal (8,9,11,12,23).Acyl-HSL signaling controls a number of bacterial processes, including virulence factor production, secondary metabolite production, and biofilm development in Pseudomonas aeruginosa (25,27,46) and conjugal transfer in Agrobacterium tumefaciens (10,29,49). Generally, LuxR and LuxI homologs serve as signal receptors and signal generators, respectively. Depending on the system, the signal varies in acyl group length and substitution (11), and these acyl side chain differences confer signal specificity (7, 35). Differences in acyl chain lengths are also a factor in signal permeability. Short-chain acyl-HSLs, like N-3-oxohexanoyl-HSL (3OC6-HSL) and butanoyl HSL, can diffuse freely through the cell membrane (14, 26). While still diffusible, long-chain acyl-HSLs like the P. aeruginosa signal N-3-oxododecanoyl-HSL (3OC12-HSL) appear to partition to the cell membrane. The MexAB-OprD efflux pump and perhaps other efflux pumps can aid in 3OC12-HSL export (26).Rhodobacter capsulatus and Paracoccus denitrificans are members of the ␣ group of the Proteobacteria. These free-living organi...

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“…RNA phage 06 of Pseudomonas is a typical example of an encapsulated prokaryotic virus whose particle is incorporated into the recipient cell during infection (Calender 1988). The gene transfer agent (GTA) of Rhodopseudomonas is reported to be encapsulated (Wall et al 1975, Solioz & Marrs 1977. Transformasomes from Haemophilus are reported to produce membranous material which is capable of encapsulating exogenous DNA in the surroundings of the cell (Kahn et al 1983).…”

Section: Morphology Of Vlpsmentioning

confidence: 99%

“…These rod-shaped marine strains were classified as members of the Superfamily IV by 16s-rRNA analysis (De Ley 1991), and by having ubiquinone-l0 as the sole component of coenzyrne Q (abbreviated as ubiquinone-10-possessing marine bacteria: QlOMB). Spontaneous releases of VLPs from eubacterial strains have been seldom reported, and are considered as being quite unusual, although some similar phenomena in archaeand photosynthetic bacteria were mentioned by Reiter et al (1987), Shaefer et al (1974), Solioz & Marrs (1977, Wall et al (1975), Wood et al (1989), andSchleper et al (1992). Recently, a high occurrence of spontaneously induced temperate phages together with high frequency of a generalized transducing trait in natural isolates of Salmonella have been reported (Schicklmaier & Schmieger 1995).…”

Section: Introductionmentioning

confidence: 95%

Generalized gene transfer by virus-like particles from marine bacteria

Chiura¹

1997

Aquat. Microb. Ecol.

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Spontaneous VLP (virus-like particle) production and VLP-mediated gene transfer into Escherichia coli AB1157 as recipient was demonstrated. Five marine isolates (Alc 096, Alc 233, Alc 252, Agrobacterium kieliense and Flavobacterium sp. 11604) were investigated for their potential to produce VLP as well as for the gene transfer capability of these VLPs to the E. col1 recipient. These strains are classified as ubiquinone-10-possessing marine bacteria (QIOMB) in the 16s-rRNA Superfamily IV VLPs were obtained from 100 h cultured broth of all strains examined. VLP-host ratio after 100 h growth culture was: Alc 233, 1.54; Alc 252, 1.26; Alc 096, 1.06; Flavobacterjum sp. 11604, 0.69; and A. kieliense, 0.06. These ratios were smaller than those found in the marine environment. However, the spontaneously produced VLP number can be considered as high because the reported numbers are relatively low from coliphage h (0.005) and phage Mu (-0.0001). VLP-mediated gene transfer was examined using an auxotrophic mutant of E. coli (AB1157) with 4 amino acid deficiencies (leu, pro, his, arg)as recipient at multiplicity of infection (MOI) of 0.1. Through this treatment, VLPs showed lethal effect on the recipient. The survival rate of control was: Alc 096, 7%; Alc 252, 8 % ; A. kieliense, 17%; Flavobacterium sp. 11604,31%; and Alc 233,40%. At the same time, all the purified VLPs derived from these 5 strains successfully transferred genes to rescue genetlc defects of the recipi.ent. Overall average efficiency of VLP-mediated gene transfer at MO1 of 0.1 was estimated to be between 2.62 X' 10-3 and 3.58 X 10-'per VLP particle. Loci of employed genetic markers were dispersed on the E. coli chromosome with mutual distance of 121, 1154, 1397 and 364 kb between them. Since VLPs from different sources showed similar gene transfer efficiency in respect to the genet~c marker rescued, it is suggested that VLPs from QlOMB transferred genes as generalized transduction. These results indicate that the VLPs produced by certain marine bacteria may be an important element for both non-specific generalzed horizontal gene transfer towards a broad range of bacterial hosts and population control in the marine environment.

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Gene transfer agents, bacteriophages, and bacteriocins of Rhodopseudomonas capsulata

Cited by 118 publications

References 11 publications

Identification of Genes of VSH-1, a Prophage-Like Gene Transfer Agent of Brachyspira hyodysenteriae

Identification of Genes of VSH-1, a Prophage-Like Gene Transfer Agent of Brachyspira hyodysenteriae

Long-Chain Acyl-Homoserine Lactone Quorum-Sensing Regulation of Rhodobacter capsulatus Gene Transfer Agent Production

Generalized gene transfer by virus-like particles from marine bacteria

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