Further properties of P-2 R-factors of <i>Pseudomonas aeruginosa</i> and their relationship to other plasmid groups

Shahrabadi, M Shamsi; Bryan, L. E.; Elzen, H. M. Van Den

doi:10.1139/m75-086

Cited by 33 publications

(21 citation statements)

References 5 publications

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“…Results of incompatibility studies reported here assigned R772 to the P-1 group (Stanisich, 1974;Bradley & Rutherford, 1975;Shahrabadi et al, 1975;Bryan et al, 1973;Jacoby, 1974; although its incompatibility interactions with R751 are llot typical of members of this group. Plasmids RP4, R702 or R1033, for example, interact reciprocally with R751, eliminating and being eliminated by it Smith et al, 1975).…”

Section: Discussionmentioning

confidence: 60%

Properties of R Plasmid R772 and the Corresponding Pilus-specific Phage PR772

Coetzee

Lecatsas

Coetzee

et al. 1979

Journal of General Microbiology

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R plasmid R772 was isolated from a strain of Proteus mirabilis and is a self-transmissible P-1 incompatibility group plasmid having a molecular weight of about 27 x lo6. It renders bacterial hosts resistant to kanamycin. Phage PR772 was isolated as a phage dependent on the presence of R772 in bacterial hosts. It is hexagonal-shaped with a diameter of 53 nm, has a thick inner membrane and no tail. Vaguely defined appendages are sometimes apparent at some vertices and the phage possesses double-stranded DNA. The DNA has a guanine plus cytosine molar content of 48':d. The phage is sensitive to chloroform and has a buoyant density of 1.26 g ~m -~. These observations suggested that the inner membrane of the phage could contain lipid. Phage PR772 differs in morphology from the doublestranded DNA plasmid-specific phages PR4 and PRRl which adsorb to tips and sides, respectively, of sex pili coded for by P-1 incompatibility group plasmids. Phage PR772 formed clear plaques which varied in diameter. Serologically, phages PR772 and PR4 are possibly related though very distantly, but the two phages have identical host ranges. Phage PR772 adsorbed by one of its apices to tips of sex pili coded for by plasmid R772 in Escherichia coli. It also formed plaques on Salmonella typhimurium, Proteus morganii and Providence strains harbouring this plasmid as well as strains of E. coli carrying plasmids of incompatibility groups N or W. The phage produced areas of partial clearing on lawns of P. mirabilis PM5006 harbouring plasmid R772, the P-1 incompatibility group plasmid RP4, the W group plasmid RSa or the N group plasmid N3, and on lawns of Providence strain P29 carrying plasmid RP4.

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Section: Discussionmentioning

confidence: 60%

Properties of R Plasmid R772 and the Corresponding Pilus-specific Phage PR772

Coetzee

Lecatsas

Coetzee

et al. 1979

Journal of General Microbiology

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“…Aminoglycoside transport seems to respond to the magnitude of the proton-motive force generated by respiration. In addition, initial aminoglycoside entry under (3,14).…”

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confidence: 99%

Mechanism of Aminoglycoside Antibiotic Resistance in Anaerobic Bacteria: Clostridium perfringens and Bacteroides fragilis

Bryan

Kowand

Elzen

1979

Antimicrob Agents Chemother

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166

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Cell-free amino acid incorporation using ribosomes from strains of either Clostridium perfringens or Bacteroides fragilis was shown to be susceptible to inhibition by streptomycin and gentamicin. Ribosomes bound dihydrostreptomycin as effectively as ribosomes from Escherichia coli. No inactivation of streptomycin or gentamicin was detected by cell extracts of either anaerobic bacterial species. B. fragilis, grown without added hemin, menadione, and fumarate, and C. perfringens did not show any time-dependent accumulation of dihydrostreptomycin or gentamicin at concentrations tested. Decreased resistance to aminoglycosides and time-dependent uptake of dihydrostreptomycin at 500 ,ug/ml was observed with B. fragilis grown with hemin, menadione, and fumarate. With the last additions, cytochrome b was detected by cytochrome spectra of B.fragilis. These results demonstrate that anaerobic bacteria unable to carry out oxygen-or nitrate-dependent electron transport are resistant to streptomycin and gentamicin because of failure to transport aminoglycosides. The induction of fumarate-dependent electron transport in B. fragilis is associated with some aminoglycoside transport that is of poor efficiency relative to bacteria with electron transport to oxygen or nitrate.The strictly anaerobic bacteria Clostridium perfringens and Bacteroides fragilis are resistant to aminoglycosides. Streptomycin and gentamicin are not effectively transported into facultatively anaerobic bacteria under anaerobic conditions (2, 3). They are transported, although less effectively, if nitrate is provided in place of oxygen as a terminal electron acceptor in Escherichia coli and Pseudomonas aeruginosa (H. M. Van Den Elzen and L. E. Bryan, unpublished data). Recently a model has been proposed for the entry of aminoglycosides into bacteria (4) which could account for these observations. The model proposes that initial aminoglycoside entry (energy-dependent phase I [4]) is most effectively driven by energy obtained from electron transport using oxygen (or, alternatively, nitrate) as a terminal electron acceptor. This energy is used to create a receptor state for aminoglycoside binding and transport by a component of the cytoplasmic membrane. This component could be a transport carrier utilized by some other solute (or solutes) or, less likely, specific for aminoglycosides. The possibility of this type of carrier seems unlikely, in our opinion, because of the inability to demonstrate transport competition during energy-dependent phase I with a series of compounds structurally related to aminoglycosides and streptomycin.

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“…Plasmids of this incompatibility group can be transferred between different species of Pseudomonds but cannot be transferred to members of the Enterobacteriaceae (Shahrabadi, Bryan & Van Den Elzen, 1975). The ability of RPLII to transfer to A .…”

Section: Resultsmentioning

confidence: 99%