OBJECTIVES The purpose of this study was to determine whether two different strains of mice, that are reproductively unresponsive to photoperiod, adjust immune function in response to photoperiod. SETTING AND DESIGN Adult male C3H/HeN (C3H) and C57BL/6 (C57) mice were each placed into either a long (LD 16:8) or short (LD 8:16) photoperiod for 10 weeks (n = 15/ group). METHODS Blood was coll...

BACKGROUND: There is not enough information about theeffects of heat stress and photoperiod on different lobes structure.OBJECTIVES: The present study aims at determining thehistological changes and the rate of changes in each lobes of ratprostate, affected by photoperiod changes and heat stress.METHODS:To this end, 15 adult male wistar rats were divided tothree groups: 1. the control group in ...

Bark storage proteins (BSPs) accumulate in the inner bark parenchyma of many woody plants during autumn and winter. We investigated the effect of a short-day (SD) photoperiod on the accumulation of the 32-kilodalton bark storage protein of poplar (Populus deltoides Bart. ex Marsh.) under controlled environmental and natural growing conditions. Sodium dodecyl sulfate-polyacrylamide gel electroph...

The selfing plant Arabidopsis thaliana has been proposed to be well suited for linkage disequilibrium (LD) mapping as a means of identifying genes underlying natural trait variation. Here we apply LD mapping to examine haplotype variation in the genomic region of the photoperiod receptor CRYPTOCHROME2 and associated flowering time variation. CRY2 DNA sequences reveal strong LD and the existence...

The temporal organization of some physiological parameters in rabbits by evaluating the circatrigintan rhythms of some haematochemical and haematological parameters, and of rectal temperature, in New Zealand white rabbits was studied. For 30 days before the study the animals all followed the same pattern of daily activity with the natural photoperiod for that season, and were fed on hay ad libi...

To investigate the changes in ovarian maturity in the tropical walking catfish, 15 females and 15 males (7 months old) were maintained under constant warm water temperature (23-25•Ž) and natural photoperiod until the age of 31 months old. Blood and ovarian oocytes were sampled monthly. Histological observation of the oocytes revealed that 10-31 months old females always possessed mature oocytes...

This study examines whether the photostimulation of sexual activity in young bucks improves reproductive performance "male effect" comparison to adult males. The experimental design was a 2 × with variables: age and photoperiodic treatment bucks. Ninety-three anoestrous does were distributed into four groups depending on kind male used: (1.26 years old, n = 6) or old (5.15 6). Half each group m...

With widespread planting of Bt cotton and an associated reduction in the use of broad-spectrum insecticides, the mirid bugs Apolygus lucorum (Meyer-Dür) and Adelphocoris suturalis Jakovlev (Hemiptera: Miridae) become major pests of cotton in northern China in recent years. Both species overwinter as diapausing eggs that may enhance ability to survive the cold winter. The effects of photoperiod...

Seasonal changes in day length enhance or suppress immune function in individuals of several mammalian species. Siberian hamsters (Phodopus sungorus) are long-day breeders that adjust reproductive physiology and behavior, body mass, and immune function following exposure to short photoperiods. Photoperiods of intermediate-duration, encountered in nature by juvenile hamsters born in early-spring...