Search PubMed⌕ Search

Biomedical subjects

D M Stark

Publications and source records attributed to D M Stark.

44 records · Page 3Linked to original sources
PubMed1969

Estimation and identification of Streptococcus dysgalactiae protective antibody in sera of rabbits and cattle.

Rabbit and cow anti-Streptococcus dysgalactiae sera were tested by bacterial agglutination, complement fixation, hemagglutination, and immunodiffusion for the presence of antibody. The results of these tests were compared with mouse-protection studies on the same serum to estimate which in vitro test would best reflect the in vivo protective capacity of serum. Identification of the antibody constituents responsible for the mouse protection, hemagglutination, and complement fixation titers were established by reacting whole and diluted antisera with mercaptoethanol before and after testing. Results indicate that the complement fixation test may be a more accurate indicator of IgG protective bovine and rabbit antibody, whereas the hemagglutination test may more readily reflect a wider range of protective antibody levels and IgM. The complement fixation test showed some shared responses to IgG and IgM in both the rabbit and cow, whereas the IgM components seemed to be the predominant factor influencing hemagglutination titers in the rabbit and more so in the bovine. Mouse protection tests with mercaptoethanol-treated cow and rabbit sera indicate that the protective capacity of these antisera is shared between IgM and IgG components.

Agglutination Tests↗
PubMedDate not supplied

Progress and problems in evaluating and validating alternative assays in toxicology.

Various techniques have been proposed and subsequently developed as potential replacements for whole-animal topical toxicology assays. Comparisons of in vitro and in vivo endpoints, the solubility of test agents, solvent effects, interactions between components of complex test samples and the standardization of data presentation are factors that influence not only individual laboratory results but interlaboratory reproducibility and the acceptance of newly developed alternative methods. Representative alternative test systems for evaluating topical toxicity are discussed. Examples of problems, data and solutions based on the authors' experience and on experience in other laboratories are reviewed. Specific problems in choosing endpoints, comparing results, recognizing responses of different types of target cell, evaluating the influences of support media in culture and interpreting published animal-based data are included.

Animals↗
PubMedDate not supplied

PHA production, from bacteria to plants.

The genes encoding the polyhydroxyalkanoate (PHA) biosynthetic pathway in Ralstonia eutropha (3-ketothiolase, phaA or bktB; acetoacetyl-CoA reductase, phaB; and PHA synthase, phaC) were engineered for plant plastid targeting and expressed using leaf (e35S) or seed-specific (7s or lesquerella hydroxylase) promoters in Arabidopsis and Brassica. PHA yields in homozygous transformants were 12-13% of the dry mass in homozygous Arabidopsis plants and approximately 7% of the seed weight in seeds from heterozygous canola plants. When a threonine deaminase was expressed in addition to bktB, phaB and phaC, a copolyester of 3-hydroxybutyrate and 3-hydroxyvalerate was produced in both Arabidopsis and Brassica.

Acetyl-CoA C-Acyltransferase↗