Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ampicillin-resistant strains of Shigella dysenteriae type 1 isolated in epidemics in Mexico, Central America, and Bangla Desh were examined for the presence of plasmid deoxyribonucleic acid (DNA) by gel electrophoresis. All strains contained a heterogeneous population of plasmids. Transfer experiments to Escherichia coli K-12 indicated that the ampicillin resistance determinant (Ap(r)) was located on a 5.5-megadalton (Mdal) plasmid identical in all Shiga strains examined, as judged by DNA hybridization and by its molecular properties. This 5.5-Mdal plasmid contained the ampicillin transposon (TnA) sequences. There was not a high degree of homology between the Shiga Ap(r) plasmid DNA and DNA obtained from Ap(r)Salmonella typhi strains isolated from typhoid epidemics in Mexico, previous to the dysentery outbreaks. Although low, the degree of reassociation observed indicated that probably part of the TnA sequence was present in S. typhi DNA. The DNA hybridization experiments showed, in addition, that there was a high degree of homology among Ap(r) plasmids isolated from different enterobacteria, and this identity was confirmed by restriction endonuclease activity. These results together with their similarities in molecular and replicative properties indicate that the Ap(r) plasmids, as was suggested for the Sm(r) Su(r) plasmids, possibly evolved once and then epidemiologically spread in the Enterobacteriaceae.
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PMID:Characterization of an R-plasmid associated with ampicillin resistance in Shigella dysenteriae type 1 isolated from epidemics. 32 94

Restriction endonuclease analysis (REA) was used to type eight well-characterised strains of Treponema hyodysenteriae originating from the U.K., Canada and the U.S.A., and 16 isolates from cases of swine dysentery in Western Australia (W.A.). Several of the W.A. isolates were also serotyped by the method of Baum and Joens (1979), and the two typing techniques were compared. REA typing was more discriminatory than serotyping, being able to distinguish strains within serotypes. The new technique was neither more difficult nor more time-consuming to perform than serotyping. Within the 16 W.A. isolates, three different REA patterns were identified, with common patterns found on different farms. The eight overseas strains had seven different REA patterns, all of which could be distinguished from the patterns of the W.A. isolates.
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PMID:Typing of Treponema hyodysenteriae by restriction endonuclease analysis. 275 76

A group of transfer derepressed R factors (pKMR plasmids) was identified with the methods of conjugation and transformation in 2 antibiotic resistant strains of the dysentery bacillus, i. e. Shigella flexneri 3c and Sh. sonnei isolated from patients with acute dysentery. The antibiotic resistance in S. flexneri was controlled by plasmid pKMR 202-2 (Sm Tc Cm Km Su) with a molecular weight of 59 MD and that in Sh. sonnei was controlled by 2 plasmids, i. e. pKMR 203-2 (Ap Sm Tc Cm Km Su) and pKMR 203-3 (Ap Tc Cm Su) with molecular weights of 99 and 65 MD, respectively. When treated with restriction endonuclease BamH 1 plasmids pKMR 203-2 and pKMR 203-3 had each only one fragment with the similar molecular weight (7.7 MD). At the same time plasmid pKMR 202-3 differed from plasmid pKMR 202-2 only by the presence of an additional fragment BamH 1 with a molecular weight of 7.7 MD. The other 6 fragments of both plasmids had similar molecular weight. The data suggest that though plasmids pKMR 202-2 and pKMR 203-3 differ in their phenotypic features, they are closely related and possible belong to the same Inc-group. It was also shown that plasmid pKMR 202-2 segregated on transformation with formation of a nonconjugative plasmid pKMR 202-1 with a molecular weight of 16.6 MD.
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PMID:[Physicochemical characteristics of transfer derepressed pKMR plasmids]. 703 38

A PCR assay for the detection of Serpulina hyodysenteriae in diagnostic specimens was developed on the basis of sequence analysis of a recombinant clone designated pRED3C6. Clone pRED3C6, which contained a 2.3-kb DNA fragment unique to S. hyodysenteriae, was identified by screening a plasmid library of S. hyodysenteriae isolate B204 genomic DNA in Escherichia coli by colony immunoblot with the mouse monoclonal antibody 10G6/G10, which was produced against cell-free supernatant antigens from the same isolate. Southern blot analysis of HindIII-digested genomic DNA of S. hyodysenteriae serotypes 1 through 7 and of four weakly beta-hemolytic intestinal spirochetes, including Serpulina innocens, with the 2.3-kb DNA fragment of pRED3C6 indicated that the cloned sequence was present exclusively in the seven serotypes of S. hyodysenteriae. An oligonucleotide primer pair for PCR amplification of a 1.55-kb fragment and an internal oligonucleotide probe were designed and synthesized on the basis of sequence analysis of the 2.3-kb DNA fragment of pRED3C6. Purified genomic DNAs from reference isolates of S. hyodysenteriae serotypes 1 through 9, S. innocens, weakly beta-hemolytic intestinal spirochetes belonging to genotypic groups distinct from those of reference Serpulina spp., other cultivable reference isolates of the order Spirochaetales, and enteric bacteria including Escherichia coli, Salmonella spp., Campylobacter spp., and Bacteroides vulgatus were amplified with the oligonucleotide primer pair in a hot-start PCR. The 1.55-kb products were obtained only in the presence of genomic DNA from each of the nine serotypes of S. hyodysenteriae. The specificity of the 1.55-kb products for S. hyodysenteriae was confirmed on the basis of production of a restriction endonuclease pattern of the PCR products identical to the predicted restriction map analysis of pRED3C6 and positive hybridization signal with the S. hyodysenteriae-specific internal oligonucleotide probe. By using total DNA obtained from normal swine feces inoculated with decreasing concentrations of S. hyodysenteriae cells, the sensitivity of the PCR assay was calculated to be between 1 and 10 organisms per 0.1 g of feces. The PCR assay was 1,000 times more sensitive than conventional culture of dysenteric feces on selective medium. There was complete agreement between the results of PCR assays and anaerobic culture on selective agar medium with diagnostic specimen (n = 9) obtained from six farms on which there were cases with clinical signs suggestive of swine dysentery. Detection of S. hyodysenteriae by PCR amplification of DNA has great potential for rapid identification of S. hyodysenteriae in diagnostic specimens.
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PMID:Rapid detection of Serpulina hyodysenteriae in diagnostic specimens by PCR. 807 94

Transfer of shigella R-plasmids in vivo has seldom been demonstrated. Strains of Shigella dysenteriae type 1 and Shigella flexneri type 5b were isolated from a Bulgarian traveller who visited Vietnam and developed dysentery, which was treated with trimethoprim/sulfamethoxazole (TMP/SMZ) for a short time. Both species of shigellae are unusual in Bulgaria where strains of S. sonnei predominate. Both shigella strains were multiresistant to the same antimicrobial agents. Each strain contained a 48-kilobase plasmid that conferred the entire resistance phenotype to a susceptible Escherichia coli. Restriction endonuclease patterns of plasmid DNA from the respective strains were identical. Transmissible plasmids of the same resistance phenotypes and restriction patterns were isolated from the patient's colonic E. coli. Transconjugants hybridized to a dihydrofolate reductase type I-DNA probe. These studies support the hypothesis that R-plasmid transfer may occur between non-pathogenic, faecal strains and pathogenic shigellae, a process that may have been facilitated by inadequate treatment with TMP/SMZ at the onset of the illness.
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PMID:In vivo R-plasmid transfer in a patient with a mixed infection of shigella dysentery. 814 99

Pulsed-field gel electrophoresis (PFGE) has been used successfully to discriminate between strains of many different bacterial species. In this study, digestion of bacterial DNA with the restriction endonuclease NotI and PFGE were evaluated for the typing of isolates of Shigella dysenteriae type 1, an important cause of epidemic dysentery. There were 27 isolates from four outbreaks of dysentery, and 44 isolates from endemic dysentery cases and a laboratory culture collection. The epidemic isolates yielded two types each with two subtypes, whereas the endemic isolates and culture collection yielded eight types with numerous subtypes. These findings suggest that S. dysenteriae 1 can be typed by PFGE.
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PMID:Evaluation of pulsed-field gel electrophoresis for typing of Shigella dysenteriae type 1. 1045 Oct 2

Pulsed-field gel electrophoresis (PFGE) was applied as a molecular typing tool for the spirochaete Serpulina hyodysenteriae, the agent of swine dysentery. Analysis of a collection of 40 mainly Australian isolates, previously characterized by other methods, divided these into 23 PFGE types. This confirmed that there are many strains of the spirochaete in Australia. PFGE was more discriminatory for strain typing than both multilocus enzyme electrophoresis and serotyping. It had similar discriminatory power to restriction endonuclease analysis, but the results of PFGE were easier to interpret. When applied to 29 isolates collected from 4 farms over periods of up to 8 years, 2 PFGE patterns were found on 3 farms, and a single pattern on the other. In each case a new strain had apparently emerged as a variant of an original parent strain. PFGE was found to be a powerful technique for investigating the molecular epidemiology of swine dysentery outbreaks.
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PMID:Analysis of Serpulina hyodysenteriae strain variation and its molecular epidemiology using pulsed-field gel electrophoresis. 1048 49

The purpose of this study was to develop and apply a multilocus sequence typing (MLST) scheme to study the molecular epidemiology of Brachyspira hyodysenteriae, the aetiological agent of swine dysentery. Sequences of seven conserved genomic loci were examined in 111 B. hyodysenteriae strains. Fifty-eight of these previously had been analysed by multilocus enzyme electrophoresis (MLEE), and for some the results of pulsed field gel electrophoresis (PFGE), restriction endonuclease analysis (REA) and/or serotyping also were available. The discriminatory power of these methods was compared. The strains were divided into 67 sequence types (STs) and 46 amino acid types (AATs) by MLST. The Index of Association value was significantly different from zero, indication that the population was clonal. Eleven clonal complexes (Cc) comprising between 2 and 10 STs were recognised. A population snapshot based on AATs placed 77.5% of the isolates from 30 of the AATs into one major cluster. The founder type AAT9 included 13 strains from nine STs that were isolated in Australia, Sweden, Germany and Belgium, including one from a mallard. The MLST results were generally comparable to those produced by MLEE. The MLST system had a similar discriminatory power to PFGE, but was more discriminatory than REA, MLEE or serotyping. MLST data provided evidence for likely transmission of strains between farms, but also for the occurrence of temporal "micro-evolution" of strains on individual farms. Overall, the MLST system proved to be a useful new tool for investigating the molecular epidemiology and diversity of B. hyodysenteriae.
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PMID:Multilocus sequence typing as a tool for studying the molecular epidemiology and population structure of Brachyspira hyodysenteriae. 1936 14