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Biomedical subjects

C Hamelin

Publications and source records attributed to C Hamelin.

68 records · Page 4Linked to original sources
PubMed1975

Characterization of mucoid mutants of Escherichia coli K-12 isolated after exposure to ozone.

Seventy mucoid mutants retaining the phenotypic properties of the ultraviolet-induced lon strains of Escherichia coli K-12 were isolated after treatment of strain MQ259 (lon+) with ozone. They produce mucoid colonies at 37 C on minimal agar, are abnormally sensitive to radiation, and tend to grow in long aseptate filaments after irradiation with ultraviolet light. Results indicate also that ozone sensitivity, radiosensitivity, and mucoidy are pleiotropic properties of the lon gene.

Agar↗
PubMedDate not supplied

Reliable identification of herpes simplex viruses by DNA restriction endonuclease analysis with EcoRI.

A simple procedure that permits the rapid identification of clinical isolates of herpes simplex virus (HSV, type 1 or type 2) on the basis of stable and type-specific differences in the EcoRI restriction endonuclease patterns of the HSV-1 and HSV-2 genomes was tested for reliability. Complete concordance was first obtained for 298 HSV isolates typed by standard laboratory procedures and by analysis of the DNA profiles. Two other HSV isolates showing intermediate biologic, immunologic, and/or biochemical properties were unambiguously identified by restriction endonuclease analysis of their genomes. Identical diagnostic results were also obtained by independent laboratories for another series of 150 HSV isolates after analysis of the EcoRI digestion products. As compared with other restriction enzymes, little intratypic variation in the DNA fragments selected for immediate identification of the isolates was found with EcoRI. The procedure used here, which does not require the purification and/or the radiolabeling of viral DNA, thus appears as most appropriate for the unambiguous typing of large numbers of HSV clinical isolates.

DNA Restriction Enzymes↗
PubMedDate not supplied

DNA topoisomerase activity associated with simian virus 40 nucleoprotein complexes.

Simian virus 40 (SV40) chromatin extracted from nuclei of infected monkey cells (CV1) was sedimented in neutral sucrose gradients, before and after digestion with bovine pancreatic RNase I-A or DNase I. DNA topoisomerase (TI) activity was found associated with RNase-resistant, DNase-sensitive SV40 nucleoprotein complexes. After polyacrylamide gel electrophoresis, a number of proteins with a molecular mass between 40 and 70 kDa were seen at the level of viral DNA peaks, some of which may represent catalytically active breakdown products of the TI enzyme. Large protein complexes were observed under the electron microscope in association with the viral chromosomes and appear to correspond to the SV40 DNA replication complex, including TI. Our results suggest that TI activity is indeed associated with the viral minichromosomes undergoing replication in vivo.

Animals↗
PubMedDate not supplied

[Intracellular changes induced by the canine infectious laryngotracheitis virus (CAV-2)].

Canine infectious laryngotracheitis virus, an adenovirus designated CAV-2, induces numerous changes in the nucleus and cytoplasm of canine kidney cells (MDCK). The following features could be observed on ultrathin sections examined in the electron microscope: a shift of the nucleolus towards the nuclear membrane and a compression of the latter by the virus particles; the release of virions into the cytoplasm following the tearing or evagination of the nuclear membrane; the attachment of virus particles onto the numerous microtubules of the infected cell. Microfilaments appear to be involved into the vectorial movement of virus particles towards the cytoplasmic membrane in the final phase of infection.

Adenoviridae↗