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Biomedical subjects

P B Applewhite

Publications and source records attributed to P B Applewhite.

At least 19 recordsLinked to original sources
PubMed1977

Protein synthesis inhibition alters Drosophila mating behavior.

Fruit fly Drosophila pseudoobscura virgin AR females mate preferentially with AR males given a choice between AR and or males. However, AR females which mated with or males when young show a significant change in sexual selection in favor of or over AR males in subsequent simultaneous choice tests. Ingestion of food moistened with 4 ml cycloheximide (400 microng/ml) produces 75% protein synthesis inhibition in the female flies. Females exposed to cycloheximide (CXM) immediately after their initial copulation with or males resemble virgin flies in their choice of mates, and mate preferentially with AR males. Females exposed to CXM before their initial copulatory experience with or males resemble or-experienced but untreated (no CXM) flies in their choice of mates, and mate preferentially with or males. The change in sexual preference shown by females with prior copulatory experience resembles learning in that it is subject to disruption by CXM in ways analogous to those reported in the literature.

Animals↗
PubMed1974

Potassium flux and leaf movement in Samanea saman. I. Rhythmic movement.

Samanea leaflets usually open in white light and fold together when darkened, but also open and dose with a circadian rhythm during prolonged darkness. Leaflet movement results from differential changes in the turgor and shape of motor cells on opposite sides of the pulvinus; extensor cells expand during opening and shrink during closure, while flexor cells shrink during opening and expand during closure but change shape more than size. Potassium in both open and closed pulvini is about 0.4 N. Flame photometric and electron microprobe analyses reveal that rhythmic and light-regulated postassium flux is the basis for pulvinar turgor movements. Rhythmic potassium flux during darkness in motor cells in the extensor region involves alternating predominance of inwardly directed ion pumps and leakage outward through diffusion channels, each lasting ca 12 h. White light affects the system by activating outwardly directed K(+) pumps in motor cells in the flexor region.

Biological Transport, Active↗
PubMed1973

Protein synthesis during endogenous rhythmic leaflet movement in Albizzia.

A rhythm was found in protein synthesis accompanying rhythmic leaflet opening and closing in the dark in the plant Albizzia. More protein was synthesized during the opening of the leaflets than during the closing. Furthermore, an inhibitor of protein synthesis, cycloheximide, prevented rhythmic opening of leaflets but had no effect on rhythmic closing. It is suggested that protein synthesis is involved in the movement across membranes of K(+) ions that cause turgor changes and leaflet movement.

Circadian Rhythm↗