Fastidious Gram‐negative bacteria: Meeting the diagnostic challenge with nucleic acid analysis

Abstract

Cop.vriahr 8 A P M I S 1995~~ MPUU8 KFN 0903-464 I Fastidious Gram-negative bacteria: Meeting the diagnostic challenge with nucleic acid analysis. APMIS 103: 609427, 1995. The extended panorama of fastidious Gram-negative bacteria (FGNB) as opportunistic etiological agents of infectious diseases in immunocompromised patients is largely due to improved medical expertise and technology. The heightened awareness of infectious diseases due to FGNB species mandates comprehensive classification and identification systems as a basis for rapid and reliable diagnostics. The most useful approaches are combinations of nucleic acid techniques such as hybridization, genetic transformation, amplification and base sequence analysis with selected conventional criteria. Among these approaches, the widely distributed feature of natural competence in these organisms facilitates the use of the biological method of genetic transformation as a valuable addition to the more common nucleic acid techniques. We describe the development of the taxonomy of FGNB through the last four decades, with particular emphasis on the families Neisseriaceae, Moraxellaceae, and Pasteurellaceae.

Microbial horizontal gene transfer and the DNA release from transgenic crop plants

“…Presently the fraction of transformable organisms among all prokaryotes is probably greatly underestimated. It should be noted also that the passive influx of DNA into cells (e.g., the 'artificial' transformation of Escherichia coli by plasmid DNA after treatment with divalent cations and temperature shifts or by electroporation as Lorenz and Wackernagel (1994) and reference B to that in Tønjum et al (1995) employed in molecular studies and gene technology; Dower et al, 1988;Hanahan, 1983) is improbable but not impossible under certain conditions in nature (Baur et al, 1996;Demanèche et al, 2001a). Unlike natural transformation, under these artificial conditions duplex DNA enters the cell and may persist if it is in the form of a plasmid while linear duplex DNA is rapidly destroyed by cellular DNases specific for degradation of linear double strands (Hanahan, 1987).…”

The RecBCD and SbcCD DNases suppress homology-facilitated illegitimate recombination during natural transformation of Acinetobacter baylyi

“…In numerous prokaryotes, natural transformation is one of the major horizontal gene transfer processes allowing the intra-and interspecific exchange of genetic information (Lorenz & Wackernagel, 1994;Tønjum et al, 1995;de Vries et al, 2004), and it is a driving force both in the generation of diversity and for evolution (Arber, 2000). During natural transformation, a competent cell binds to a double-stranded DNA molecule, introduces a doublestrand break, takes up the DNA, and transfers a single strand into the cytoplasm while the complementary strand is degraded (Dubnau & Provvedi, 2000;Chen & Dubnau, 2004).…”

The RecJ DNase strongly suppresses genomic integration of short but not long foreign DNA fragments by homology‐facilitated illegitimate recombination during transformation of Acinetobacter baylyi

“…Natural transformation is a main horizontal gene transfer process in prokaryotes that allows the intra‐ and interspecific exchange of genetic information (Lorenz and Wackernagel, 1994; Tønjum et al ., 1995) and is a driving force for the generation of genetic variation and evolution (Arber, 2000). During transformation, a DNA uptake‐competent cell binds free double‐stranded DNA, introduces a double‐stranded break into the DNA and actively transfers one strand into the cytoplasm in 3′‐5′ direction while the complementary strand is degraded (Dubnau and Provvedi, 2000; Chen and Dubnau, 2004).…”