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Biomedical subjects

A Lewin

Publications and source records attributed to A Lewin.

At least 127 records · Page 7Linked to original sources
PubMed1977

Restriction cleavage map of mitochonrial DNA from the yeast Saccharomyces cerevisiae.

Mitochondrial DNA (mtDNA) from the yeast Saccharomyces cerevisiae was cleaved by restriction endonucleases Eco RI, Hpa I, Bam HI, Hind III, Pst I, and Sal I, yielding 10, 7, 5, 6, 1, and 1 fragments, respectively. A physical ordering of the restriction sites on yeast mtDNA has been derived. Yeast mtDNA cannot be isolated as intact molecules, and it contains nicks and gaps which complicate the use of conventional fragment mapping procedures. Nevertheless, the position of each of the restriction sites was obtained primarily by reciprocal redigestion of isolated restriction fragments. This procedure was supplemented by co-digestion of mtDNA with a multisite enzyme and a single-site enzyme (i.e., Sal I or Pst I) which provided a unique orientation for overlapping fragments cleaved by Sal I or Pst I. The data obtained from these approaches were confirmed by analysis of double and triple enzyme digests. Analysis of partial digest fragments was used for positioning of the smallest Eco RI fragment. A comparison of mtDNA from four grande strains (MH41-7B, 19d, TR3-15A, and MH32-12D) revealed similar, but slightly varying restriction patterns, with an identical genome size for each of approximately 5 X 10(-7) d or 75 kb. A fifth grande strain, D273-10B from S. cerevisiae, revealed restriction patterns different from those of the above strains, with a smaller genome size of 70 kb.

DNA Restriction Enzymes↗
PubMed1976

The measurement of jaw movement. Part I.

A new method of recording the movements of a point on the mandible appears to be a valuable addition to the many means which are available for attempting to fathom the secrets of jaw movements. While in its present form this method does not fully describe any of the movements of the jaws, the over-all patterns recorded may be of significance.

Dental Articulators↗
PubMed1976

The measurement of jaw movement. Part II.

To summarize, the principles and the application of an apparatus have been described which without appreciable physical restraint provides graphic representations of the movements of a point on the mandible in three conventional anatomic planes-sagittal, coronal, and horizontal. The apparatus also provides data which permit an estimation of the magnitude and direction of movement of a point on the jaw during function in relation to time. This information prepares the way for the calculation of the path of the selected point in space, as well as its mean velocity and acceleration.

Humans↗
PubMed1975

Restriction endonuclease analysis of mitochondrial DNA from grande and genetically characterized cytoplasmic petite clones of Saccharomyces cerevisiae.

Digestion of grande mitochondrial DNA (mtDNA) BY EcoRI restriction endonuclease gives rise to nine fragments with a total molecular weight of 51.8 x 10(6). HindIII digestion yields six fragments with a similar total molecular weight. Specific restriction fragments can be detected despite the fact that yeast mtDNA consists of a heterogeneous distribution of randomly broken molecules. Digestion patterns of 10 genetically characterized petite clones containing various combinations of five antiobiotic resistance markers indicate that the petite mtDNA predominantly represents deletion of the grande genome. The petite mtDNAs contained up to seven EcoRI restriction fragments which comigrate with grande restriction fragments, and at least one fragment that did not correspond to any in the grande. Some strains contained multiple fragments with mobility different from that of grande; these fragments were usually present in less than molar concentrations. The genetic markers were associated with individual sets of restriction fragments. However, several internal inconsistencies prevent the construction of a definitive genetic fragment map. These anomalies, together with the digestion patterns, provide strong evidence that, in addition to single contiguous deletion, other changes such as multiple deletion and heterogeneity of mtDNA populations are present in some of the petite mtDNAs.

DNA Restriction Enzymes↗