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 first outbreak of infections caused by an SHV-5 producing strain of Klebsiella pneumoniae is reported. Within a period of 1 year and 9 months, multiresistant K. pneumoniae strains caused severe infections, mostly of the lower respiratory tract, in 22 patients. The strains were resistant to penicillins, third-generation cephalosporins, aztreonam, chloramphenicol, tetracycline and co-trimoxazole. The resistance determinants were transferable to Escherichia coli. All isolates produced a beta-lactamase with a pI of 8.2. Ceftazidime was hydrolyzed at this band. These characteristics, together with the resistance phenotype, are identical to those of a reference strain producing the beta-lactamase SHV-5. The K. pneumoniae strains of all patients were identical in their capsular serotype (K1), plasmid pattern and plasmid fingerprint after digestion with Dra I restriction endonuclease. We conclude that this outbreak was caused by the spread of one clone of K. pneumoniae producing SHV-5 beta-lactamase among patients of different wards. Our results indicate a real risk for failure of therapy by third-generation cephalosporins in intensive care patients due to SHV-5 producing pathogens.
Infection
PMID:Spread of Klebsiella pneumoniae producing SHV-5 beta-lactamase among hospitalized patients. 844 75

Infection of cultured mammalian cells with the Leporipoxvirus Shope fibroma virus (SFV) causes the induction of a novel uracil DNA glycosylase activity in the cytoplasms of the infected cells. The induction of this activity, early in infection, correlates with the early expression of the SFV BamHI D6R open reading frame which possesses significant protein sequence similarity to eukaryotic and prokaryotic uracil DNA glycosylases. The SFV BamHI D6R open reading frame and the homologous HindIII D4R open reading frame from the Orthopoxvirus vaccinia virus were cloned under the regulation of a phage T7 promoter and expressed in Escherichia coli as insoluble high-molecular-weight aggregates. During electrophoresis on sodium dodecyl sulfate-polyacrylamide gels, the E. coli-expressed proteins migrate with an apparent molecular mass of 25 kDa. The insoluble protein aggregate generated by expression in E. coli was solubilized in urea and, following a subsequent refolding step, displayed the ability to excise uracil residues from double-stranded plasmid DNA substrates, with the subsequent formation of apyrimidinic sites. The viral enzyme, like all other characterized uracil DNA glycosylases, is active in the presence of high concentrations of EDTA, is substrate inhibited by uracil, and does not display any endonuclease activity. Attempts to inactivate the HindIII D4R gene of vaccinia virus by targeted insertion of a dominant xanthine-guanine phosphoribosyltransferase selection marker or direct insertion of a frame-shifted oligonucleotide were uniformly unsuccessful demonstrating that, unlike the uracil DNA glycosylase described for herpesviruses, the poxvirus enzyme is essential for virus viability.
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PMID:A poxvirus-encoded uracil DNA glycosylase is essential for virus viability. 847 56

Infection with Helicobacter hepaticus causes chronic active hepatitis in certain strains of mice and is associated with hepatocellular carcinoma in A/JCr mice. Like the gastric helicobacters, H. pylori and H. mustelae, H. hepaticus possesses a high level of urease activity. However, the H. hepaticus urease structural gene sequences have not been previously determined, and the role of the urease enzyme in colonization and in pathogenesis is not known. PCR was used to amplify a portion of the urease structural genes from H. hepaticus genomic DNA. Amplified DNA fragments were cloned, and the nucleotide sequence was determined. The deduced amino acid sequence of the partial H. hepaticus ureA gene product was found to exhibit 60% identity and 75% similarity to the predicted H. pylori UreA. The deduced amino acid sequence of a partial H. hepaticus ureB gene product exhibited 75% identity and 87% similarity to the predicted H. pylori UreB. Diversity among H. hepaticus isolates was evaluated by means of a restriction fragment length polymorphism (RFLP) assay. The 1.6-kb fragments within the ureAB open reading frames, amplified from 11 independent isolates, were digested with the restriction endonuclease HhaI. Three distinct RFLP patterns were observed. Identical RFLP profiles were noted in sequential isolates of one strain of H. hepaticus during an 18 month in vivo colonization study, suggesting that the urease genes of H. hepaticus are stable. The urease genes among H. hepaticus strains were also well conserved, showing 98.8 to 99% nucleotide sequence identity among three isolates analyzed. These findings indicate that H. hepaticus has urease structural genes which are homologous to those of the gastric Helicobacter species and that these gene sequences can be used in a PCR and RFLP assay for diagnosis of this important murine pathogen.
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PMID:Development of a PCR-restriction fragment length polymorphism assay using the nucleotide sequence of the Helicobacter hepaticus urease structural genes ureAB. 970 72

Pulsed field gel electrophoresis of restriction endonuclease digested genomic DNA from a collection of clinical isolates of Rhodococcus equi was used to compare strain diversity on different Thoroughbred horse farms over time. Restricted diversity was found among the isolates tested, as the same strains were detected on multiple farms and in multiple years. Marked variation occurred in strain prevalence with some strains being represented by single isolates, and the most prevalent by 26 isolates. There were dominant strains on some farms and the prevalence of some strains differed between farms. Infection with multiple strains was noted in some cases where multiple isolates from a single foal were examined.
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PMID:Diversity of isolates of Rhodococcus equi from Australian thoroughbred horse farms. 1006 85

Aeromonas trota is recognized as an important enteropathogen, and its haemolysin (aerolysin) is purported to be one of the virulence factors. Rapid detection and identification of A. trota is important for early and specific diagnosis of the infectious diseases that it causes. Synthetic oligonucleotide primers were used in a polymerase chain reaction (PCR) technique to amplify a species-specific sequence of the aerA gene, which encodes the aerolysin of A. trota. A DNA fragment of 622 bp was amplified from both lysed cells and isolated DNA from A. trota. The identity of the amplified 622 bp fragment was confirmed by digestion with BamH I restriction endonuclease, which produced the predicted 557 and 65 bp fragments. The lower limit for detection of the aerA gene by PCR amplification was 10 pg of total DNA or 10-15 cells ml-1. Primer specificity for A. trota was determined by the PCR assay with cells of 55 strains of Aeromonas sppincluding all of the 14 currently recognized DNA hybridization groups. A strain of Aeromonas enteropelogenes that had been reclassified as A. trota was also PCR positive. The method described here can be used to detect aerolysin-producing A. trota (hybridization group 13) strains from environmental and clinical samples without the use of selective media or additional biochemical tests.
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PMID:Identification of Aeromonas trota (hybridization group 13) by amplification of the aerolysin gene using polymerase chain reaction. 1020 99

Several different epidemiologic typing methods have been applied in studies of microbial pathogens. These methods include the more traditional nonmolecular approaches as well as the more sophisticated molecular typing methods. Application of traditional epidemiologic typing methods, such as antibiogram, serotyping, biotyping, and phage typing, have occasionally been useful in describing the epidemiology of infectious diseases. However, these methods have generally been considered to be too variable, labor intensive, and slow to be of practical value in epidemiologic investigations. In response to these limitations, several techniques have been adopted from the molecular biology field for use as epidemiologic typing methods and have been applied in studies of bacteria, fungi, viruses, and protozoa. The most widely used molecular typing methods are the DNA-based methods, such as plasmid profiling, restriction endonuclease analysis of plasmid and genomic DNA, Southern hybridization analysis using specific DNA probes, and chromosomal DNA profiling using either pulsed-field gel electrophoresis or polymerase chain reaction-based methods. The various molecular typing methods may be applied to the investigation of outbreaks of infections or may be used in the context of epidemiologic surveillance. For outbreak investigation, typing methods are used to compare isolates from a suspected outbreak to delineate clonally related and unrelated strains with the goal of short-term control of transmission. In the context of epidemiologic surveillance, molecular typing methods may be used to monitor geographic spread and prevalence shifts of epidemic and endemic clones with the goal of long-term evaluation of preventive strategies or for the detection and monitoring of emerging and reemerging infections. The specific typing method selected may vary with the task at hand; however, the typing studies must always be used to supplement, rather than replace, careful epidemiologic investigation.
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PMID:Molecular epidemiology in the care of patients. 1053 97

Influenza is worldwide one of the deadliest infectious diseases. Lethal influenza mutants can unpredictably arise, as in the 1918 pandemic, or in the 1997 Hong Kong influenza outbreak. Vaccines are today the only protective prophylactic agents, and development of potent new anti-influenza drugs of therapeutic effectiveness appears urgent. It is the aim of the present review, to summarize and discuss the different investigational approaches to this goal. In Medline- and several internet virology database-searches, numerous citations were compiled, and selected according to their relevance to the different topics discussed. The antiviral agents are classified according to their target in the viral replication cycle: proteolytic activation of haemagglutinin, attachment of the virus to specific cell-surface receptors, endocytosis and fusion with the endosomal membrane, uncoating of the nucleocapsid, multiplication, i.e. synthesis of viral RNA and mRNA, and release of the new virus generation from the host cell surface. Potential drugs, directed towards each of these replication steps are described with respect to their mechanism of action, antiviral activity, toxic side effects and induction of resistance. The most promising candidates for safe and potent new influenza drugs, are antiviral agents, directed towards a virus-specific, well conserved target, such as inhibitors of virus-cell fusion, inhibitors of RNA transcriptase and endonuclease, and inhibitors of neuraminidase. It can be hoped that in the near future potent and therapeutically effective anti-influenza drugs will be available.
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PMID:Influenza chemotherapy: a review of the present state of art and of new drugs in development. 1120 14

Modern molecular genetics relies on the ability to map the positions of genes on chromosomes, relative to known DNA markers. The first such DNA markers described were Restriction Fragment Length Polymorphisms, but any restriction endonuclease used for RFLP mapping is just one member of a restriction-modification pair. For each restriction endonuclease, there is a companion methyltransferase (MTase) that has the same DNA sequence specificity. Therefore, in principle, it should be possible to use MTases rather than restriction enzymes to detect polymorphic sites in DNA. We have used sequence-specific DNA MTases to detect polym orphisms in closely related viral pathogens. If at least one MTase recognition site is present in PCR-amplified DNA, then methyl groups are incorporated; if no MTase site is present, then methyl groups are not incorporated. When several different sequence-specific DNA MTase reactions are carried out, the pattern of methyl incorporation defines a DNA MTase genotype. DNA MTase Genotyping (DMG) can be used to rapidly diagnose heritable or infectious diseases, to immunochemically detect DNA at defined 2 to 8 base pair sites, or to characterize the amplicons by constructing ordered maps.
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PMID:Genotyping of DNA using sequence-specific methyltransferases followed by immunochemical detection. 1268 Jun 4

A retrospective epidemiologic study was conducted to evaluate the application of an objective quantitative algorithm for estimating genetic similarity from restriction endonuclease analysis data. The analysis was performed to assist the determination of chronologic trends in an Aujeszky's disease viral epidemic in a geographic region. DNA from each viral isolate obtained during the epidemic was digested with 4 restriction endonucleases and molar ratio labeled to generate separate fragment patterns that were simultaneously compared using the algorithm. The resultant estimates of genetic similarity were then used in conjunction with time of virus isolation and specific geographic location of the outbreaks to identify the probable sources of infection and the patterns of spread among swine herds. This type of quantitative analysis enabled a more precise and objective approach than previously has been applied to the interpretation of restriction endonuclease data, thereby demonstrating the benefit of this methodology for the investigation of infectious disease outbreaks.
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PMID:Application of a quantitative algorithm to restriction endonuclease analysis of Aujeszky's disease (pseudorabies) virus from a geographically localized outbreak. 1296 55

Interleukin-1 (IL1) is a potent endogenous pyrogen and inducer of the acute phase response, and these innate immune responses are an important part of the human host's initial reaction to infection by the malaria parasite. In addition, several single-nucleotide polymorphisms (SNPs) in this region have previously been demonstrated to be associated with susceptibility to infectious disease. Therefore, a possible association with malaria susceptibility was investigated. A total of 13 polymorphic markers were used in a two-stage screening strategy to genotype a Gambian case-control study group by either restriction endonuclease digestion or the Sequenom MassARRAY assay. This involved an initial screen of 188 severe cases and 188 mild controls, and if there was a significant association with a malaria phenotype (P<0.05); this was followed by screening of the remaining 1044 samples. Two markers showed significant association with malaria: interleukin-1 alpha +4845 G --> T (P=0.035 for mild malaria versus controls) and interleukin-1 beta +3953 C --> T (P=0.030 for mild malaria versus severe malaria). Haplotypes constructed using the SNPHAP programme were not associated with any of the malaria phenotypes investigated. In summary, if IL1 variants are involved in malaria susceptibility in the Gambia at all, then the effects are small.
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PMID:Interleukin-1 gene cluster polymorphisms and susceptibility to clinical malaria in a Gambian case-control study. 1467 70


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