Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

The confirmation at the DNA level of the existence of clonal variants within Escherichia coli O2 and O18 serotypes has been shown by Southern hybridization analysis of restriction endonuclease digested genomic DNA and subsequent probing with contiguous subclones of the E. coli O101 rfb region. The O101 rfb subclones are believed to represent a conserved region of DNA (Heuzenroeder et al. Molec. Microbiol, in press) and identify serotype variants by means of restriction fragment length polymorphisms (RFLP) within homologous DNA of O2 and O18 E. coli. A number of different restriction enzymes have been used singly and in combination to digest the genomic DNA, thereby allowing construction of restriction maps of the region displaying homology to the O101 rfb region subclones. This analysis further substantiates previously defined evolutionary relationships between O2 and O18 E. coli. These simple probes appear to be able to provide the same clonal information as a battery of isoenzyme, outer membrane protein (OMP) and lipopolysaccharide (LPS) analyses.
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PMID:Demonstration of clonal variation amongst O-antigen serotype variants of Escherichia coli O2 and O18 using DNA probes to the rfb region of the E. coli strain B41 (O101:K99/F41). 247 Jun 38

Although most of the rat-liver AP (apurinic/apyrimidinic) endonuclease is in chromatin, some activity is found in microsomes. A quantitative assay of the microsomal AP endonuclease is described. The enzyme is a peripheral membrane protein that is located on the outside surface of microsomes. All the binding sites on the microsomes appear to have the same affinity for the AP endonuclease, suggesting the presence of receptors for the enzyme. The AP endonuclease is displaced from its membrane attachment by submicromolar concentrations of the karyophilic signal of SV-40 T antigen. The AP endonuclease receptors are likely to be on the cytosolic side of the endoplasmic reticulum. It is suggested that binding of the protein to these receptors might be the first step of the transport mechanism that enables the AP endonuclease to penetrate into the nucleus. The same mechanism utilizing the same receptors might be used by other karyophilic proteins, including SV-40 T antigen.
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PMID:The rat-liver microsomal AP endonuclease. The endoplasmic reticulum is presented as a net thrown into the cytosol to capture newly synthesized karyophilic proteins. 247 70

The outer membrane protein (OMP) composition (OMP typing) of 46 fecal Aeromonas strains from hybridization groups (HGs) 1 (A. hydrophila; n = 10), 4 (A. caviae; n = 16), and 8 (A. veronii; n = 20) were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a phenotypic typing method. Almost every isolate of HG-1 and HG-8 had a unique OMP profile, in contrast to isolates of HG-4, which were separated into five different OMP types. It was possible to recognize HGs 1, 4, and 8 by OMP profiles. Twenty-three Aeromonas strains from HGs 1 (n = 5), 4 (n = 10), and 8 (n = 8) were tested by whole-cell DNA restriction endonuclease analysis (REA) as a genetic typing method. All strains tested by REA (with SmaI) had different DNA digestion patterns. Although additional DNA-rRNA hybridization analyses with SmaI and 16S and 23S rRNAs from Escherichia coli showed a reduction in the number of restriction bands to 8 to 13 hybridized fragments, the discriminative value was less when compared with that obtained by REA. The individual differences found by REA were used to analyze whether patients remained colonized by the same Aeromonas strain. Of 11 patients with diarrhea, 2 had a different isolate on repeat culture. In addition, one of nine tested fecal samples contained two Aeromonas isolates with different REA patterns. These results indicate that during diarrheal disease the intestinal tract may be colonized simultaneously with different Aeromonas isolates.
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PMID:Typing of Aeromonas strains by DNA restriction endonuclease analysis and polyacrylamide gel electrophoresis of cell envelopes. 247 93

EPEC adherence factor (EAF) plasmids from three strains of enteropathogenic Escherichia coli (EPEC) - E2347/69 (O127:H6), E20517 (O111:H2) and E24582 (O142:H6) - were examined. The EAF plasmids were all marked with ampicillin resistance by transposition of Tn801 to give pDEP1, pDEP2 and pDEP11, respectively. All three plasmids showed incompatibility with an FIme and an FIV plasmid and had some similarity in restriction enzyme digest patterns. Plasmid pDEP1 differed from pDEP2 and pDEP11 in being autotransferring and fertility-inhibition positive. An EAF probe consisting of a 1 kb BamHI-SalI restriction endonuclease fragment of the prototype EAF-associated plasmid pMAR2 hybridized to similar-sized SalI-BamHI fragments of pDEP1 and pDEP11 but to a different-sized fragment of plasmid pDEP2. Loss of the EAF plasmids from EPEC strains resulted in a marked reduction in the ability of these strains to adhere to HEp-2 cells. The EAF-plasmid-negative variants did not express a 94 kDa outer-membrane protein (OMP). When these EAF plasmids were reintroduced into EAF-plasmid-negative EPEC strains a high level of adherence equivalent to that of the parent EPEC strains was restored and a 94 kDa OMP was usually expressed. However, when EAF plasmids were transferred into E. coli K12 or non-EPEC E. coli the host strains either did not adhere or adhered poorly to the HEp-2 cells. These transconjugants did not express a 94 kDa OMP.
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PMID:Properties of adherence factor plasmids of enteropathogenic Escherichia coli and the effect of host strain on expression of adherence to HEp-2 cells. 257 33

An 820 bp AccI-PstI fragment of the 60 kDa cysteine rich outer membrane protein (CrP) gene from C. trachomatis serovar L1 was used as a probe to locate the 60 kDa CrP gene of a recent serovar B trachoma isolate (Jali 20/OT). The probe hybridized to a single 1.8 kb SpeI fragment in Southern blot analyses of different restriction endonuclease digests of C. trachomatis serovar B DNA. This fragment was ligated into Lambda Zap II arms and Bluescript SK(-) recombinants, released by infection with the helper phage R408, were used as template for DNA sequence determination. Sequence analysis demonstrated a very high level of homology between the Jali 20/OT 60 kDa CrP and the previously published serovar L1 60 kDa CrP with only 8 out of 507 amino acid substitutions between the two proteins.
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PMID:Chlamydia trachomatis 60 kDa cysteine rich outer membrane protein: sequence homology between trachoma and LGV biovars. 261 91

It is assumed that the causative bacteria in children suffering from otitis media reach the middle ear via the eustachian tube. The purpose of this investigation was to use endonuclease restriction of bacterial chromosomal DNA to compare isolates of nontypable (NT) Haemophilus influenzae obtained from the nasopharynx and from middle ear (ME) effusions of patients with otitis media. Strains of NT H. influenzae were isolated from the nasopharynx (NP) and affected ME from a group of 13 unrelated children with otitis media with effusion (OME). For 12 of these children, identical strains were isolated from the NP and ME in a first episode of OME. Each of these 12 sets differed from the other 11. Six of these children suffered from a second episode of OME with NT H. influenzae. Five of these children with recurrence again had identical NP and ME strains. These results suggest that at the time of an episode of OME, there is one predominant strain of NT H. influenzae that colonizes both the NP and ME. The strains of NT H. influenzae isolated from all six of the second episodes were different from strains from the first episode, indicating turnover of the predominant strain in the NT H. influenzae population between episodes. When we investigated three siblings with concurrent episodes of OME, we found that they shared several similar strains of NT H. influenzae, thereby demonstrating that within a family, transmission of NT H. influenzae from child to child is possible. These results from DNA fingerprinting were essentially identical when compared with results from outer membrane protein subtyping performed on the same set of strains. The analysis of endonuclease restriction patterns of total genomic DNA provides a sensitive measure of genetic dissimilarity between strains and represents an easily applicable method for epidemiological and transmission studies of bacterial infections associated with NT H. influenzae.
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PMID:Determination of the epidemiology and transmission of nontypable Haemophilus influenzae in children with otitis media by comparison of total genomic DNA restriction fingerprints. 278 38

Several molecular techniques were used for comparison of the novel Chlamydia agent, TWAR, with Chlamydia trachomatis and Chlamydia psittaci. Unlike all serotypes of C. trachomatis and most strains of C. psittaci, the eight TWAR isolates examined did not contain extrachromosomal DNA. TWAR was readily distinguished from C. trachomatis or C. psittaci by restriction endonuclease analysis, whereas identical or nearly identical restriction patterns were observed among the TWAR isolates. Southern blot analysis with a gene encoding a portion of the C. trachomatis serovar L2 major outer membrane protein as the probe showed that TWAR, like C. psittaci, contained sequences homologous to this gene. However, while the hybridization patterns were identical for all TWAR isolates, they differed from those of any of the other Chlamydia species tested. A PstI gene bank containing TWAR DNA was constructed in pUC19. Random fragments were purified and used for probing Chlamydia chromosomal digests. All of the five probes tested were TWAR specific, with the TWAR isolates showing identical patterns of homology. Qualitative studies of the DNA homology revealed that TWAR did not have significant homology to any of the Chlamydia strains assayed. Collectively, these results demonstrate that the TWAR isolates represent a single strain or closely allied genotypes and are clearly distinct from any of the other chlamydiae tested.
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PMID:Characterization of the new Chlamydia agent, TWAR, as a unique organism by restriction endonuclease analysis and DNA-DNA hybridization. 282 63

The structural gene for the major outer membrane protein (MOMP) from Chlamydia trachomatis was cloned and sequenced. A lambda gt11 recombinant (lambda gt11/L2/33) that contains a portion of the MOMP coding sequence was used to probe a lambda 1059 library constructed from DNA obtained from C. trachomatis serovar L2. Selected lambda 1059 recombinants were mapped with endonuclease restriction enzymes. The MOMP gene was mapped to the 5' end of a BamHI fragment of approximately 9 kilobases. Contiguous endonuclease restriction fragments identified within this region permitted the selection of specific fragments for subcloning and DNA sequencing. The MOMP gene consisted of a 1,182-base-pair open reading frame that encoded 394 amino acids and ended with three stop codons. The known amino-terminal amino acid was preceded by 22 amino acids whose sequence was compatible with a leader or signal sequence. The primary structure of MOMP determined from the translated DNA sequence demonstrated nine cysteine residues and a remarkably homogeneous distribution of charged and hydrophobic residues.
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PMID:Sequence analysis of the major outer membrane protein gene from Chlamydia trachomatis serovar L2. 294 65

Native Alaskans have a high incidence of disease caused by invasive Haemophilus influenzae type b and represent an isolated population for epidemiological study. We used plasmid DNA analysis and subtyping of outer membrane proteins as markers to characterize 29 ampicillin-resistant, invasive strains and seven ampicillin-resistant, noninvasive strains of this organism from distinct geographic regions. All 36 strains produced beta-lactamase; 34 strains transferred resistance by conjugation. Seven of the 36 strains harbored detectable plasmid DNA: four had a molecular mass of 40 MDa, and three had a molecular mass of 3 MDa. Furthermore, 20 transconjugants had a similar large plasmid, and four had a similar small plasmid. Ten of 12 transconjugants with either the large, small, or undetectable plasmid DNA were able to retransfer resistance. Transformation of resistance was successful with two large plasmids. DNA-DNA hybridization studies revealed that 33 of 36 strains had DNA homology. Restriction endonuclease digestion of 10 large plasmids revealed five patterns; identity was evident within a geographic region, and similarity existed between regions. Seven restricted plasmids demonstrated an identical pattern with a small beta-lactamase probe. Ampicillin resistance in these isolates from Alaska is primarily due to a common, 40-MDa conjugative plasmid that mediates beta-lactamase production, a finding which differs from that for ampicillin-resistant plasmids isolated elsewhere in the United States. Despite variable outer membrane protein profiles of the distinct strains of H. influenzae type b, the plasmids shared significant DNA homology. It appears that a common genetic element was responsible for the dissemination of this phenotype for resistance in Alaska.
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PMID:Molecular epidemiology of plasmid-mediated ampicillin resistance in Haemophilus influenzae type b isolates from Alaska. 298 65

Vibrio strains isolated from diseased turbot in an experimental fish farm on the Atlantic coast of northwest Spain were identified as Vibrio anguillarum. The isolates shared many biochemical characteristics with V. anguillarum strains obtained from other sources, and harboured a plasmid species that showed extensive homology with plasmid pJM1, carried by V. anguillarum strain 775 isolated from an epizootic in North America. Restriction endonuclease analysis showed that the two plasmids were very similar albeit not identical. The presence of the plasmid in the turbot isolates was associated with their ability to cause disease in fish. Plasmid-carrying bacteria could also grow under conditions of iron limitation. Two outer membrane proteins, of 86 and 79 kDal, were induced, and a similar siderophore activity to that produced by V. anguillarum 775 was also detected under these conditions. The 86 kDal outer membrane protein cross-reacted immunologically with antiserum raised against the outer membrane protein OM2 produced by strain 775. Nonvirulent plasmidless derivatives were unable to grow under iron-limiting conditions, and were also unable to produce either siderophore activity or the 86 kDal outer membrane protein, suggesting the plasmid-mediated nature of these components.
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PMID:Plasmids mediating iron uptake in Vibrio anguillarum strains isolated from turbot in Spain. 299 66


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