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Biomedical subjects

M Gough

Publications and source records attributed to M Gough.

77 records · Page 5Linked to original sources

Second locus of bacteriophage P22 necessary for the maintenance of lysogeny.

A temperature-sensitive allele of a locus of phage P22, known to be involved in establishment of lysogeny, has been isolated. This mutant, P22 ts mnt, forms stable lysogens at 30 C which are induced by heating to 43 C. This shows that this locus is involved in the maintenance of lysogeny. The ts mnt locus is about 18 recombination units away from the c region. The wild allele, mnt(+), is dominant over mnt and is responsible for a cytoplasmically diffusible product.

Chromosome Mapping↗

Methylated bases in the host-modified deoxyribonucleic acid of Escherichia coli and bacteriophage lambda.

Gough, Michael (Brown University, Providence, R.I.), and Seymour Lederberg. Methylated bases in the host-modified deoxyribonucleic acid of Escherichia coli and bacteriophage lambda. J. Bacteriol. 91:1460-1468. 1966.-The deoxyribonucleic acid (DNA) from strains of Escherichia coli and phage lambda was examined to determine whether the types or amounts of methionine-derived methylated bases present correlated with the host-specific modification of that DNA. The DNA of strain C600 (which has K-12 modification specificity) and of a modificationless mutant of C600 are similar in their content of 5-methylcytosine and 6-methylaminopurine. Strains Bc251 and its P1-lysogen differ in P1-controlled specificity, but they have the same content of 6-methylaminopurine, and both lack 5-methylcytosine in their DNA. Phage lambda contains the same methylated bases as its host of origin, but in reduced amounts and in different proportions. Although minor amounts of these methylated bases may have importance as a result of their location, the presence of the majority of these methylated bases is irrelevant to the specificity of host modification of DNA.

Alkylation↗

The potential use of laser capture microdissection to selectively obtain distinct populations of cells for proteomic analysis--preliminary findings.

Proteomics-based studies offer a powerful complementary approach to DNA/RNA-based investigations and are now being applied to investigate aspects of many diseases including cancer. However, the heterogeneous nature of tissue samples often makes interpretation difficult. We have undertaken a study into the potential use of a novel laser capture microdissection (LCM) system to isolate cells of interest for subsequent proteomic analysis. Retrieval of selected cells is achieved by activation of a transfer film placed in contact with a tissue section, by a laser beam (30 or 60 microm diameter) which is focused on a selected area of tissue using an inverted microscope. The precise area of film targeted by the laser bonds to the tissue beneath it and these cells are then lifted free of surrounding tissue. Although the technique has been shown to be readily compatible with subsequent analysis of nucleic acids, little information is yet available regarding the application of protein-based analyses to the captured tissue. We report here preliminary data regarding the potential use of the LCM system in combination with two-dimensional electrophoresis to examine protein profiles of selected tissue areas. Electrophoretic profiles of proteins from normal and malignant renal tissue samples showed little change following LCM, nine selected proteins showed identical mass spectrometric sequencing profiles, and two selected proteins retained antigenicity. Dissection of epithelial tissue from a sample of normal human cervix resulted in enrichment of some proteins compared with analysis of the whole tissue. LCM will be a valuable adjunct to proteomic studies although further detailed validation is necessary.

Amino Acid Sequence↗