Search PubMed⌕ Search

Biomedical subjects

L A Nelson

Publications and source records attributed to L A Nelson.

42 records · Page 3Linked to original sources
PubMed1966

Temperature-dependent anomalies in the growth of microorganims.

Davey, C. B. (North Carolina State University, Raleigh), Raymond J. Miller, and Larry A. Nelson. Temperature-dependent anomalies in the growth of microorganisms. J. Bacteriol. 91:1827-1830. 1966.-Water in the liquid phase (0 to 100 C) has been shown, by others, to undergo subtle changes in its physical structure at approximately 15, 30, 45, and 60 C. It has been suggested that these temperature-dependent anomalies in the structure of water may have biological implications. After incubation in a polythermostat, direct cell counts were made to determine temperature-growth interactions for the four bacteria which were used to cover the temperature range from 5 to 70 C: Pseudomonas fragi, 5 to 25 C; Streptococcus faecalis, 20 to 40 C; Bacillus coagulans, 35 to 55 C; and B. stearothermophilus 1518 smooth, 50 to 70 C. In all cases, growth was suppressed at the predicted temperatures, suggesting a strong interaction between the structure of water and biological activity.

Bacillus↗
PubMedDate not supplied

Relation between smoking and levels of DDT and dieldrin in human fat.

The adipose tissue of humans with known patterns of cigarette smoking was collected during 1973-74 and analyzed for DDT components and dieldrin. Although smokers are exposed to high levels of insecticides from smoke of cigarettes and some of these compounds can be stored in adipose tissue, it could not be demonstrated that a relationship exists between smoking habit and residual levels of DDT found in fat. Smokers seem able, through induction of enzymes by substances in tobacco smoke, to metabolize these insecticides at a rate approximately equal to the rate of their intake in the smoke. Dieldrin residues in black male subjects were found to be linearly related to the number of cigarettes smoked, but the factors governing this relationship were not obvious.

Adipose Tissue↗