~ ~ ~~~~The generalized transducing phage Pf 16h2 has been used to confirm linkage relationships of chromosomal markers of Pseudomonas putida previously determined from their time-of-entry in Hfr crosses, and to map new auxotrophic mutations. By means of spot matings using Hfr donors of known origin of transfer, catabolic markers forming part of a closely linked group of operons referred to as a superoperonic cluster have been shown to be chromosomally located and their map positions determined. R-prime-mediated interspecific complementation has been used to equate functionally 21 auxotrophic loci in P. putida and P. aeruginosa, and the distribution of these loci on the two genetic maps has been compared. While both maps reveal that auxotrophic markers are largely restricted to about 40% of the chromosome and that auxotrophic markers of similar phenotype are not clustered, there is evidence of at least seven chromosomal rearrangements since divergence from a presumed common ancestor.
Derivatives of the Pseudomonas aeruginosa plasmid R91-5, loaded with the transposon TnSOl, were transferred to P. putida PPN. Over 90% of exconjugants, which arose at a frequency of ca. 10-6 per donor cell, exhibited high-frequency (>10-2 per donor cell) polarized transfer of chromosomal markers. In one instance it was demonstrated by transduction that the plasmid had been inserted into a gene required for serine biosynthesis. The integrated nature of the plasmid in this and other P. putida (R91-5: :TnSOI) derivatives was supported by the failure to detect covalently closed circular DNA in these strains. The transfer origins of six different Hfr donors have been characterized genetically, and time-of-entry kinetics obtained from interrupted matings have enabled the construction of a circular genetic map 103 min in length and containing 35 markers. The genetic map of P. putida PPN shows significant. differences in marker order to that of P. aeruginosa PAO. (pMO196:HfrC) pur-400 (pMO22:HfrD) pur-400 str-404 (pMO22:HfrE) 8 This studyb This study 20 This study This study This study 20 This study This study This study This study This study This study This study This study This study This study This study This study This study This study This study This study This study This study This study This study This study This study This study This study This study This study Nalr derivative of the ATCC12633 strain MAPIO (30) This study Exconjugant from the cross PAO5(pMO22) x PPN1007 Exconjugant from the cross PAO5(pMO22) x PPN1007 Exconjugant from the cross PAO5(pMO196) x PPN1O21 Exconjugant from the cross PAO5(pMO22) x PPN1007 Exconjugant from the cross PAO5(pMO22) x PPN1O94 J. BACTERIOL.
The banding profiles generated by Bam H1 restriction endonuclease cleavage of bacterial DNA from clinical and reference isolates of Histophilus ovls, Haemophilus somnus and related bacteria were compared. H. ovis, H. somnus and Haemophilus agni isolates were found to have distinct similarities in banding profiles characterised by 10 common bands between 2.0 and 9.6 kilobases (kb). The close taxonomic relationship of these isolates was reinforced by these findings. The reference isolates examined In this study -Actinobacillus lignieresii, Actinobaclllus semlnis, H. agni, H. somnus, H. ovis, Haemophilus influenzae, Haemophilus parainfluenzae, Haemophilus parahaemolyficuscould be distinguished from each other on the basis of their characteristic banding profiles.Aciinobacillus sp were obsewed to have more bands between 2 and 23 kb compared with the H. ovis and Haemophilus sp isolates studied.Analysis of isolates from an experimental infection trial illustrated the potential of restriction endonuclease analysis in molecular epidemiological applications. It was possible to demonstrate by this means that the post-challenge isolates had identical banding profiles to the challenge (or infecting) isolate which had a distinctly different banding profile from that of pre-challenge H. ovis isolates. Furthermore, restriction endonuclease analysis of H. ovis isolates obtained from follow-up investigations of a recurrent problem of epididymitis in unmated rams, indicated that the H. ovis isolates implicated in epididymitis, were present as a single strain in a number of sheep over a period of time. This suggested that the mechanism of transmission was by perinatal preputial contamination. Aust Vet J 6 3 389-393 Results Barn HI Profiles of H. ovis and Closely Related BacteriaExamples o f the banding profiles obtained from Bam HI digests o f DNA from H. ovis (Australian) and H . somnus (North American) isolates are shown in Figure 1. The profiles o f the H . somnus isolates (lanes 2 and 3) are different from $ Seakem-LE Agarose, SUMMARY Wet chemical tests have deficiencies when applied to mixtures containing silica, which are common in the uroliths of some domestic animals. Consequently, the applicability of an infrared spectroscopic method was tested on 104 uroliths obtained from cattle, sheep, goats, horses, pigs, dogs, a chicken and a rabbit during diagnostic investigations. The following components were satisfactorily identified: silica, calcium oxalate, calcium carbonate, calcium phosphate, magnesium ammonium phosphate, magnesium phosphate and urates. The Infrared characteristics of these compounds and their mixtures are described. Aust Vet J 63: 393-396
A simple method of detection of FP plasmids with chromosome-mobilizing ability in Pseudomonas aeruginosa has been developed.
A number of enhanced chromosome mobilizing (ECM) plasmids derived from the wide host range plasmid R68 have been used to construct R-prime plasmids carrying a maximum of two map minutes of the Pseudomonas putida PPN chromosome, using Pseudomonas aeruginosa PAO as the recipient. For one ECM plasmid, pMO61, the ability to form R-primes did not correlate with the ability to mobilize chromosomes in intrastrain crosses, suggesting that different mechanisms are involved. Physical analysis of one R-prime showed that 3.5 kb of chromosomal DNA had been inserted between the tandem IS21 sequences carried by the parent ECM plasmid.
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