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)

Plasmid isolation was used to refine the epidemiologic analysis for 168 shigellosis cases in Pima County, Ariz. Plasmids of less than 20 kb were used for comparison of plasmid profiles. Plasmid patterns for each species were distinct. A total of 57 of 74 (77%) Shigella flexneri strains could be placed into seven plasmid patterns, 70 of 79 (89%) Shigella sonnei strains could be placed into seven patterns, 12 Shigella boydii strains could be placed into six patterns, and each of 3 Shigella dysenteriae strains differed. There was a correlation between plasmid patterns and serotypes for S. flexneri, and multiple plasmid patterns were found in serotypes 1, 2, and 6, offering a refinement beyond serotyping. In previous studies we found an association between Mexican travel and an S. sonnei 5.1-kb plasmid. When this plasmid was used as a probe, strong homology was seen with numerous small plasmids in all Shigella species: restriction endonuclease analysis revealed a 1.1-kb AvaI-AvaII fragment common to various plasmids of S. sonnei. S. flexneri, and S. boydii independent of species. Of 34 Pima County Shigella isolates from the mid-1970s. 8 showed plasmid patterns similar to those of the recent isolates. Some plasmids from S. sonnei, S. flexneri, and S. boydii strains isolated in the 1970s also contained the AvaI-AvaII fragment. The conservation of this specific fragment in our population for more than 12 years suggests that it may contain genes important in virulence or survival.
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PMID:Molecular epidemiology of Shigella infections: plasmid profiles, serotype correlation, and restriction endonuclease analysis. 184 48

The natural occurrence of small Hsd (host specificity for DNA) plasmids was demonstrated in restriction endonuclease-producing strains of Salmonella typhi, Shigella boydii, and Escherichia coli. The five Hsd plasmids isolated were between 5.0 and 12.2 kilobases long. The copy number of all the Hsd plasmids was high (more than 10 copies per cell). Introduction of these small plasmids into E. coli strain 0 drastically lowered the efficiency of plating of the lambda.0 phages (the efficiency of plating was less than 5 X 10(-5) PFU-1). High restriction endonuclease activities were detected in the Hsd plasmid-positive strains because of the elevated copy numbers of the hsdR+ gene. The advantages of using E. coli strains containing the small Hsd plasmids for purification of type II restriction endonucleases are discussed.
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PMID:Occurrence of small Hsd plasmids in Salmonella typhi, Shigella boydii, and Escherichia coli. 300 23

Virulent isolates of Shigella dysenteriae and Shigella boydii harboured a 140 Mdal plasmid which was either absent or deleted in spontaneously avirulent strains. Together with previous data concerning S. sonnei, S. flexneri and enteroinvasive Escherichia coli, the present results established the general role of extrachromosomal elements in the virulence of such enteroinvasive species. Among different species, these virulence plasmids showed unrelated endonuclease cleavage patterns, whereas hybridization experiments showed that homologous sequences were present throughout the molecules. These plasmids may therefore have derived from a common ancestor molecule which overcame evolutionary alterations in restriction sites. Furthermore, intraspecies and intraserotype comparison of these plasmids by endonuclease cleavage demonstrated highly conserved sequences. The consequences of these data for evolution, epidemiology and diagnosis of Shigella and enteroinvasive E. coli are discussed.
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PMID:Molecular comparison of virulence plasmids in Shigella and enteroinvasive Escherichia coli. 635 23

A strategy for the detection, identification, and differentiation of enteroinvasive Escherichia coli (EIEC) and Shigella spp. has been developed. The strategy includes (i) a multiplex PCR for the amplification of two virulence genes, i.e., iuc (222 bp) and ipaH (629 bp); (ii) amplification of the ial gene (a 1,038-bp amplicon) located within a large plasmid; and (iii) restriction fragment length polymorphism (RFLP) of the ial gene amplicon. The multiplex PCR provided three patterns. Pattern 1 (iuc-/ ipaH+) was found in 10 (67%) of 15 EIEC strains tested, pattern 2 (iuc+/ipaH-) in only 2 (4.4%) of 46 non-EIEC isolates, whereas pattern 3 (iuc+/ipaH+) was observed in all Shigella spp. and also in 5 (33%) of 15 EIEC strains tested. The pattern 3 EIEC strains were all positive for the ial gene. The PCR-RFLP of the ial gene amplicon using the endonuclease AclI was used to differentiate Shigella spp. from the EIEC strains that belonged to pattern 3. The ial gene was present in 21 (38%) of 56 and 6 (40%) of 15 Shigella spp. and EIEC strains tested, respectively. The PCR-RFLP of the ial gene amplicon divided the strains in two types. Type 1 did not contain the restriction enzyme site and was found in 6 (100%) of 6 EIEC strains, 4 (80%) of 5 Shigella boydii, and 4 (100%) of 4 Shigella dysenteriae strains tested. Type 2, which gave two fragments of 286 and 752 bp, was observed in 5 (83%) of 6 Shigella fiexneri strains and 6 (100%) of 6 Shigella sonnei strains. Detection, identification, and differentiation of Shigella spp. and EIEC were achieved by analyses of the PCR patterns and RFLP types. To our knowledge, this is the first study to demonstrate a simple and rapid method for detecting, identifying, and differentiating, at the molecular level, Shigella spp. and EIEC strains. This method will have tremendous utility as an epidemiological tool and in helping to develop policies, risk assessments, and national and international methods for Shigella spp.
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PMID:Molecular strategies for the detection, identification, and differentiation between enteroinvasive Escherichia coli and Shigella spp. 1572 63