PubMed Health⌕ Search

Biomedical subjects

W E Robbins

Publications and source records attributed to W E Robbins.

At least 37 records · Page 2Linked to original sources
PubMed1967

Vitamin A deficiency: effect on retinal structure of the moth Manduca sexta.

Sphingid moths (Manduca sexta) were reared for several generations on an artificial diet deficient in vitamin A and its precursors. Retinal tissue from depleted moths was removed for histological examination. There was extensive histolysis in the retinal epithelium and underlying nervous and connective tissues. This pathology correlated with severe visual impairment, even though normal growth, metamorphosis, and reproduction occurred. In the adult this pathology could be reversed when the larvae were reared only on tobacco (its usual host) or on the artificial diet supplemented with beta-carotene or vitamin A palmitate.

Animals↗
PubMed1967

Insect hormones: alpha ecdysone and 20-hydroxyecdysone in bracken fern.

The two major molting hormones of insects, alpha ecdysone and 20-hydroxyecdysone, were isolated in crystalline form from dry pinnae of the bracken fern, Pteridium aquilinum (L.) Kuhn. Three unidentified substances with molting hormone activity were also detected. Bracken is the first plant found to contain both of the major insect ecdysones, and it is the first known plant source of alpha ecdysone.

Chromatography, Thin Layer↗
PubMed1967

Conversion of beta sitosterol to cholesterol blocked in an insect by hypocholesterolemic agents.

Two vertebrate hypocholesterolemic agents (triparanol and 22,25-diazacholesterol) block the conversion of beta-sitosterol to cholesterol in the larva of the tobacco hornworm, Manduca sexta (Johannson). A primary site of inhibitory action is the terminal step in this conversion-the reduction of desmosterol (24-dehydrocholesterol) to cholesterol. This is also the site at which these compounds inhibit de novo cholesterol biosynthesis in higher animals. Both agents severely inhibit growth and maturation of the tobacco hornworm.

Animals↗