PURPOSE The authors examined the effects of both light and circadian phase on the synthetic activity of the dopamine producing enzyme, tyrosine hydroxylase (TH), in the retina of the Midas cichlid (Cichlasoma citrinellum). METHODS TH activity was assayed in the retina-retinal pigment epithelium (RPE) complex of fish entrained to cyclic light regimens. The animals were killed throughout cyclic...

When cuttings or seedlings of Phaseolus aureus were treated proximally with malformin for 2 days in continuous white light, resistance to subsequent leaf abscission in the dark resulted. The amount of resistance diminished as the concentration of malformin decreased from 10 to 0.1 micromolar. Resistance to dark abscission persisted for 7 days in continuous light. Little resistance was obtained ...

The growth and tuberization of potatoes (Solanum tuberosum L.) maintained for 6 weeks under four different regimes of continuous irradiance were compared to plants given 12 hours light and 12 hours dark. Treatments included: (a) continuous photosynthetic photon flux of 200 micromoles per square meter per second cool-white fluorescent (CWF); (b) continuous 400 micromoles per square meter per s...

Behavioral studies are important tools for understanding the development and pathology of neurological diseases. Zebrafish are an emerging alternative model in behavioral and neurological studies as the behavioral repertoire of zebrafish (Danio rerio) is similar to humans, and nervous system structures and functions are highly conserved. In this study, we investigated alterations in day/night l...

Limited information is known on the basic biology of the recently described Phytophthora kernoviae that produces homothallic oospores. In this study, different P. kernoviae isolates were used to investigate oospore maturity, germination, and infection. All isolates produced oospores in V8 broth at 20°C in the dark by 6d. Oospores also formed at 10 and 15°C, but did not form at 25 and 28°C. Cont...

this study evaluated the effect of the intermittent light program on serum and brain melatonin concentrations, antioxidant enzyme activities, and homocysteine concentration in broiler chickens. a total of 60 one-day-old broiler chickens (cobb 500) were distributed in three light-proof controlled rooms (20 chicks per room). all birds were reared in continuous light until 3 days of age. then, chi...

The development of NADP- and NAD-dependent glyceraldehyde 3-phosphate dehydrogenase and NADH-specific glyoxylate reductase was followed in Sinapis alba cotyledons grown in the dark or under continuous red and far red light. All three enzyme activities are promoted by light, continuous far red light being more than twice as effective as continuous red light. The activities of the NADP-glyceralde...