Genetic Exchange in Natural Microbial Communities

Veal, Duncan; Stokes, H. W.; Daggard, Grant

doi:10.1007/978-1-4684-7609-5_8

Cited by 39 publications

(17 citation statements)

References 200 publications

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“…However, if it is a widespread phenomenon, genetic recombination between unrelated bacteria could confound orthodox taxonomic interpretations. Transfer of genes between unrelated bacteria was observed as long ago as 1928 (Veal et al, 1992). Antibiotic and heavy-metal resistance and the transfer of nitrogenfixing genes have long been recognized as commonly occurring events.…”

Section: Horizontal Gene Transfermentioning

confidence: 99%

Implications of alternative classifications and horizontal gene transfer for bacterial taxonomy.

Young¹

2001

International Journal of Systematic and Evolutionary Microbiology

165

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Following the publication of the Approved Lists, there has been a tendency to regard all subsequent revisions of classification as providing improved nomenclature, to be accepted without question. This takes no account of the fact that such revisions may be based on one of three alternative concepts, phenetic, phylogenetic or polyphasic classification, sometimes leading to different, valid, but incompatible nomenclature, or that some investigations are based only on subsets of relevant taxa and on limited data, leading to incomplete and sometimes confusing revisions of nomenclature. The polyphasic approach to classification has widespread support, although there appears to be a tendency to allow comparative sequence analyses of 16S rDNA to determine classification contrary to the indications of other data. In some cases, classification is based solely on 16S rDNA data. Examples are considered. Consideration is given to the criteria by which taxa are circumscribed, particularly at the level of genus and species. It is suggested that there is a need for reconciliation of the criteria by which taxa at these levels are circumscribed. Recent studies demonstrating the widespread occurrence of horizontal gene transfer suggest that there is a need for caution in monophyletic interpretations, especially when these are based on the analysis of single sequences. Keywords : phenetic, phylogenetic, polyphasic, bacterial systematics IntroductionAlthough Staley & Krieg (1984) wrote that ' bacterial classifications are devised for microbiologists, not for the entities being classified ', bacteriologists do not necessarily agree about the aims of classification. The several systems of bacterial classification that are in vogue at present are incompatible, sometimes leading to different classifications and to different schemes of bacterial nomenclature. Unless the principles underlying different classifications are understood, these different applications of names cause bewilderment. The thrust of this article is to show that no one system of classification is supreme, each offering a different perspective on evolutionary processes and serving different purposes in systematics. One problem that particularly besets discussions on bacterial taxonomy is that some terms derived elsewhere and often in the distant past are poorly defined or are used in different ways by different writers. For example, see the history of the usage of ' polyphasic ' described below. Ambiguity and lack of precision of usage are real causes of confusion. In attempting to maintain simplicity without confusion, terms are referred to Cowan (1978) and Lincoln et al. (1998) unless further explanation is felt necessary. Terms used here are not inconsistent with Tindall (1997).In 1980, the Approved Lists (Skerman et al., 1980) recorded 1792 validly published species names in 290 genera (6n2 species per genus) (Euze! by, 1997). One expectation of modern systematics has been that the increasing numbers of methods and sophisticated tools for analysis would form co...

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Section: Horizontal Gene Transfermentioning

confidence: 99%

Implications of alternative classifications and horizontal gene transfer for bacterial taxonomy.

Young¹

2001

International Journal of Systematic and Evolutionary Microbiology

165

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“…Under the coexistence of lysogenic viruses and bacteria, viruses may be seen as partners of coevolution for the supply of complementary genetic source to the bacterial community (Levin & Lenski 1983). The packaging of genetic material in a transducing particle probably represents an evolutionary survival mechanism for bacterial genes (Stozky 1989, Veal et al 1992.…”

Section: Vlp-mediated Gene Transfer Experiments Tomentioning

confidence: 99%

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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“…Moreover, these extrachromosomal elements might play crucial roles in the adaptation of bacteria during environmental changes. Horizontal gene transfer, in fact, has a major impact on the adaptability of bacteria to different conditions of life and many plasmids carrying genes for antibiotic and/or heavy metal resistance or coding for catabolic pathways have been found (2)(3). However, limited information are so far available on plasmids isolated from cold adapted organisms (4 -6).…”

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confidence: 99%