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

Single genotypic variants of HIV-I, contained in a parental cytopathic HIV-I isolate, were isolated by molecular cloning and propagated in susceptible cells. Two such HIV-I clones, designated N1T-E and N1T-A, exhibited similar restriction endonuclease maps but strikingly different biological activities. Infection of T lymphocytes or monocytes by clone N1T-E was characterized by slow kinetics and lack of significant cytopathic effects, but high reverse transcriptase activity levels in culture supernatants of chronically-infected cells. Clone N1T-A, like the parental HIV-I isolate, exhibited fast kinetics of infection in T cells and monocytes and strong cytopathicity in these cells. Full characterization of the low-cytopathic virus in comparison to the structurally similar cytopathic clone may facilitate the elucidation of the molecular basis of HIV cytopathogenicity.
 ...
PMID:Low-cytopathic infectious clone of human immunodeficiency virus type I (HIV-I). 245 68

Black-pigmented Bacteroides species are recognized as suspected pathogens of oral infections. Developments in the taxonomy of this group include description of a new asaccharolytic species, Bacteroides salivosus, and proposal for the reclassification of the asaccharolytic species into a separate genus, Porphyromonas. Studies on the pathogenicity and virulence of black-pigmented Bacteroides species have identified Bacteroides gingivalis as the most virulent species. B. gingivalis and Bacteroides intermedius have been associated with periodontal diseases; Bacteroides endodontalis is isolated specifically from infections in the oral cavity, and other black-pigmented Bacteroides species are recovered from oral mucous sites. DNA restriction endonuclease analysis was adapted for typing of B. gingivalis and B. intermedius.
Infection
PMID:Taxonomy, virulence and epidemiology of black-pigmented Bacteroides species in relation to oral infections. 273 64

Two hundred and fifty three infants were screened for cytomegalovirus (CMV) in the urine at birth and were followed up at regular intervals for one year. Twelve per cent (of 249) were excreting virus at 3 months, and 20% (of 234) at 12 months. In all cases infection was subclinical. The major factors determining risk of acquiring infection were the mother's serological state and whether the infant was breast fed. There was no association with social class, mother's age, or whether the child had been in a special care baby unit or a postnatal ward. By one year 33% (of 123) of infants of seropositive mothers had acquired CMV infection compared with 4% (of 123) born to seronegative mothers. Twenty per cent (17) of seropositive women who breast fed had virus isolated from their breast milk on at least one occasion, and 76% (13) of their infants became infected. In four mother-infant pairs comparison of CMV isolates from the mother's milk and the child's urine was made by restriction endonuclease digestion; in each pair infection had apparently occurred with the same strain of virus. All 13 infected infants followed up for three years were still shedding virus. Infection with CMV is common in infancy, and virus shedding persists for years. Congenital infection cannot be distinguished from acquired infection unless the presence of CMV in the urine is identified within three or four weeks after birth, even when clinical problems suggestive of congenital infection are present.
 ...
PMID:Early acquisition of cytomegalovirus infection. 282 27

Infection of a human lymphoblastoid B cell line (Raji cells) with type D retroviruses, originally isolated either from subhuman primates (MPMV, LV) or from permanent human cell lines (PMFV, HeLaV, HEp-2V) led to the production of type D retrovirus particles. Subsequent cocultivation of uninfected and virus-producing Raji cells was employed for the generation of sufficient amounts of covalently closed circular DNA molecules (cccDNA). Highest amounts of cccDNA were obtained after cocultivation of virus-producing Raji cells and homologous uninfected cells at a ratio of 1 to 3 for 72 hr. The cccDNAs of type D retroviruses migrated at about 4.3 kbp compared to lambda DNA/HindIII markers. Digestion of cccDNAs with restriction endonucleases which have one recognition site generated molecules of approximately 8 kbp. The restriction endonuclease site analysis of the cccDNA of type D retroviruses revealed a genomic heterogeneity among the different isolates.
 ...
PMID:Isolation and characterization of covalently closed circular proviral DNA molecules of several type D retroviruses isolated from human cell lines. 302 12

The common marmoset, Callithrix jacchus, can be infected with human varicella-zoster virus (VZV), both wild-type strain KMcC and attenuated vaccine strain Oka/Merck. Infection was accomplished with either whole-cell-associated or cell extract VZV by combined oral-nasal-conjunctival application and was characterized by substantial and persistent anti-VZV antibody responses. The infectivity of VZV for marmosets was destroyed by treatment of inocula with heat or UV light. Diluted inocula with as few as 40 PFU/ml were infectious for marmosets. The lungs were demonstrated to be a major site of viral replication; both the presence of viral antigens and signs of pneumonia were demonstrated in lung tissues. Four serial passages of VZV KMcC were carried out in C. jacchus by a process of in vitro isolation and culturing of VZV from infected lung tissue and reapplication of the cultured isolates to fresh animals. The isolated viruses were identified as VZV both serologically and by restriction endonuclease analyses. The C. jacchus infectivity model should prove useful for determining the efficacy of subunit and live recombinant VZV vaccines as well as for the study of zoster.
 ...
PMID:Successful infection of the common marmoset (Callithrix jacchus) with human varicella-zoster virus. 304 Oct 14

The gene expression of nine phages of the T7 group was compared after infection of Escherichia coli B(P1). With the exception of phage 13a which grew normally, all of them infected E. coli B(P1) abortively. Differences were found in the efficiency of host killing which ranged from 100% for phage 13a to 37% for phage A1122. Infection by T7 prevented colony formation by about 70% of the cells but they showed filamentous growth until about 2 h after infection. It was shown by SDS-polyacrylamide gel electrophoresis and autoradiography of [35S]methionine-labelled phage-coded proteins that all phages except for 13a showed measurable expression only of the early genes. No correlation was observed between killing capacity and the pattern of gene expression, and the ability to hydrolyse S-adenosyl-methionine (SAM, a cofactor for the P1 restriction endonuclease) by means of a phage-coded SAMase. Mixed infection of E. coli B(P1) with 13a and T7 yielded mixed progeny indistinguishable from that observed after mixed infection of the normal host E. coli B. Genetic crosses with amber mutants of 13a and T7 showed that the 13a marker opo+ (overcomes P one), required for growth on B(P1), is located in the early region, to the left of gene 1 (RNA polymerase gene).
 ...
PMID:Inhibition of gene expression of T7-related phages by prophage P1. 304 52

Serum samples from 247 patients with positive HIV-1 IgG serology were investigated for specific IgM antibodies. We found that 109 also reacted positively with a least one antigen in an HIV-1 IgM Western Blot and only 31 in an HIV-1 IgM enzyme-linked immunosorbent assay (ELISA). It was shown that in some of the persons, specific IgM antibodies against the gp160/120, p66, p55, gp41, p24, and p17 antigens of the virus are synthesized at some time after infection. IgM antibodies to the endonuclease-related p31 antigen were observed in one serum only. IgM antibodies against the gp160/120, p66, gp41, and p17 antigens seemed to disappear early after infection. Those against the p55 and the p24 antigens were found in 62% and 75% of investigated cases, respectively. A direct correlation between the Western Blot patterns and the IgM ELISA results was not found.
Infection
PMID:Detection of anti-HIV-1 immunoglobulin M antibodies in patients with serologically proved HIV-1 infection. 316 78

Infection control teams rely on microbiology laboratories for accurate, reproducible data to trace the spread of microorganisms in the hospital. Since few problems are recognized immediately, laboratories should save important nosocomial pathogens so that outbreak strains will be available for analysis by more sophisticated techniques, particularly since automation has reduced the amount of epidemiologically useful data generated by routine procedures. Traditional supplemental reference procedures include phage typing, biotyping, serotyping and bacteriocin typing. Recently, analysis of antibiotic resistance determinants has provided the hospital epidemiologist with additional tools. Resistant strains have been characterized by their production of specific antibiotic inactivating enzymes. Agarose gel electrophoresis and restriction endonuclease analysis of plasmid DNA have permitted precise characterization of nosocomial strains, and the spread of antibiotic resistance genes can now be followed by sensitive and specific DNA probes. DNA probes also show promise for distinguishing nosocomial strains bearing known virulence factors from strains with less pathogenic potential. Molecular genetics techniques have found an additional role in elucidating the epidemiology of nosocomial viruses, especially the herpesviruses.
 ...
PMID:New microbiological techniques for hospital epidemiology. 330 10

By means of restriction endonuclease digests and DNA/hybridisation studies we analysed ten representative methicillin-resistant Staphylococcus aureus strains of our collection for plasmid similarities and plasmid associated resistance determinants. We found that strains isolated at our laboratory contained identical or at least most similar plasmids. Isolates from another geographical origin showed different plasmid patterns. We found resistance determinants for gentamicin to be chromosomally encoded, whereas resistance to heavy metal ions and chloramphenicol was always plasmid associated. Resistance to trimethoprim, tetracycline and erythromycin was usually chromosomally mediated but could also reside on a plasmid. Our results indicate that methicillin-resistant strains from our collection may have a common origin. The clinical relevance of these results is discussed.
Infection
PMID:Plasmid fingerprinting of methicillin-resistant Staphylococcus aureus strains isolated in Hamburg. 343 80

Infection of Vero cells with African swine fever (ASF) virus resulted in a marked increase of DNase active on single-stranded DNA (ss-DNase). No increase was observed for double-stranded DNA-specific nuclease activity. In contrast to uninfected cell ss-DNase, which has a pH optimum at pH range 8.5-9, virus-induced ss-DNase is most active at pH 7. Differences in sensitivity to several ions and other modifications of the reaction mixture and considerable difference in reaction kinetics suggest that the increase in nuclease activity is due to a new virus-induced enzyme. This is strengthened by the fact that anti-ASF virus antiserum inhibits the activity of ss-DNase from infected cells but not from uninfected cells. Exclusion chromatography of the digests shows that virus-specific ss-DNase is exclusively or predominantly an endonuclease. The increase in nuclease activity of infected cells is proportional to the multiplicity of infection. Virus-specific ss-DNase is synthesized at late times after infection and its synthesis is dependent on viral DNA replication since it is not induced when infected cells are treated with cytosine arabinoside. Most of ss-DNase activity in infected cells is associated to an insoluble cytoplasmic fraction, presumably virosomes. The enzyme can also be detected in partially stripped purified virions which hydrolyze 6.9 ng DNA per microgram viral protein.
 ...
PMID:Single-stranded deoxyribonucleic acid nuclease induced by African swine fever virus and associated to the virion. 377 99


<< Previous 1 2 3 4 5 6 Next >>