The effects of different luminance levels and light sources to emmetropization in the chick were investigaed. One-day-old, forty chicks were reared under condition of unilateral visual deprivation with translucent goggle. Under normal light cycles (12-h light/12-h dark), three kinds of luminance levels and two light sources (incandescent lamp vs fluorescent lamp) were used. Three weeks after hatching, refractive error, axial length, equator diameter and corneal diameter of the eyes were measured. The deprived eyes exhibited severe myopia of -11.94 diopters (p<0.001) and refractive changes were mainly related with axial elongations. Refractive error of 1000 lux group was less myopic than 2000 lux group (p<0.05). The fellow eyes didn't show significant difference between groups. No significant changes were noted between different light source groups. The experiment suggests that different degrees of illumination under normal light/dark environment can cause different refractive changes; More studies will be needed to show that the ideal luminance condition for emmetropization in our enviroment be present.
Lighting* ; Myopia ; Photoperiod ; Refractive Errors*

Rice is a major cereal crop for China. The development of the "three-line" hybrid rice system based on cytoplasmic male sterility in the 1970s (first-generation) and the "two-line" hybrid rice system based on photoperiod- and thermo-sensitive genic male-sterile lines (second-generation) in the 1980s has contributed significantly to rice yield increase and food security in China. Here we describe the development and implementation of the "third-generation" hybrid rice breeding system that is based on a transgenic approach to propagate and utilize stable recessive nuclear male sterile lines, and as such, the male sterile line and hybrid rice produced using such a system is non-transgenic. Such a system should overcome the intrinsic problems of the "first-generation" and "second-generation" hybrid rice systems and hold great promise to further boost production of hybrid rice and other crops.
China ; Oryza ; genetics ; growth & development ; Photoperiod ; Plant Breeding ; methods

A 'circadian rhythm' is a self-sustained biological rhythm (cycle) that repeats itself approximately every 24 hours. Circadian rhythms are generated by an internal clock, or pacemaker, and persist even in the absence of environmental time cues, collectively termed 'zeitgebers.' Although organisms generate circadian rhythms internally, they are entrained by environmental stimuli, particularly the light-dark cycle. Measurement of the endogenous melatonin rhythm provides relatively reliable surrogate way of assessing the timing of the internal circadian clock. Also, core body temperature and cortisol can be used as markers of circadian rhythms. The sleep-wake cycle, body temperature, and melatonin rhythm have a stable internal phase relationship in humans and other diurnal species. They play an important role in controlling daily behavioral rhythms including task performance, blood pressure, and synthesis and secretion of several hormones. In this review, we address not only the properties, methods of measurement, and markers of circadian rhythms, but also the physiological and psychological importance of human circadian rhythms.
Blood Pressure ; Body Temperature ; Circadian Clocks ; Circadian Rhythm* ; Cues ; Humans ; Hydrocortisone ; Melatonin ; Photoperiod ; Task Performance and Analysis

The animal time structure is a basic fact of life, no matter if one wants to study it or not. The time- dependent, mostly rhythmic, and thus to a certain degree predictable, variations of biochemical and physiological functions and of sensitivity and resistance to many environmental agents are often quite large and offer not only new insight into animal physiology and pathology but also diagnostic possibilities and therapeutic advantages. Chronobiology, chronophysiology and its subspecialities, like chronopharmacology and chronotherapy, will certainly play an important role in the clinical medicine of the future. Successful application of chronobiology to veterinary clinical medicine, however, depends critically on a thorough knowledge of its basic principles.
Animals ; Animals, Domestic/*physiology ; Behavior, Animal/*physiology ; Biological Clocks/*physiology ; Circadian Rhythm/*physiology ; Humans ; Photoperiod ; Seasons

In the present study, the effects of different photoperiods on stress, immunity, and hematological parameters in ICR mice were evaluated. Fifty male ICR mice 7 weeks old (body weight, 27.3 +/- 2.5 g) were divided into five groups: DP-0 (0/24-h light/dark cycle), DP-6 (6/18-h light/dark cycle), DP-12 (12/12-h light/dark cycle), DP-18 (18/ 6-h light/dark cycle), and DP-24 (24/0-h light/dark cycle). During the experimental period, no significant differences in body weight or feed intake were observed between the groups. Hematological analysis revealed that white blood cell, red blood cell, and hemoglobin values for the DP-0 group were significantly different compared to those of the other groups. After 28 days, no significant difference in serum cortisol concentration was observed among the groups, but serum cortisol levels increased in a light exposure-dependent manner. Total serum immunoglobulin G (IgG) concentrations of the DP-0 and PD-6 groups were significantly increased compared to those of the other groups (P < 0.05), and serum total IgG levels decreased in a light exposure-dependent manner. Results of the present study indicated that various photoperiods affect hematological parameters and total serum IgG levels in ICR mice while having no significant effects on body weight, feed intake, or cortisol levels.
Animals ; Body Weight ; Erythrocytes ; Humans ; Hydrocortisone ; Immunoglobulin G ; Leukocytes ; Male ; Mice ; Mice, Inbred ICR* ; Photoperiod*

Photoperiod plays an important role in transformation from vegetative growth to reproductive growth in plants. CONSTANS (CO), as a unique gene in the photoperiod pathway, responds to changes of day length to initiate flowering in the plant. In this study, the expression level of FaCONSTANS (FaCO) gene under long-day, short-day, continuous light and continuous darkness conditions was analyzed by real-time quantitative PCR. We constructed the over-expression vector p1300-FaCO and infected into Arabidopsis thaliana by Agrobacterium-mediated method. We constructed the silencing vector p1300-FaCO-RNAi and infected into Festuca arundinacea by Agrobacterium-mediated method. The expression of FaCO gene was regulated by photoperiod. The over-expression of FaCO promoted flowering in wild type of Arabidopsis thaliana under long day condition and rescued the late flowering phenotype in co-2 mutant of Arabidopsis thaliana. Silencing FaCO gene in Festuca arundinacea by RNAi showed late-flowering phenotype or always kept in the vegetative growth stage. Our understanding the function of FaCO in flowering regulation will help further understand biological function of this gene in Festuca arundinacea.
Arabidopsis/metabolism* ; Arabidopsis Proteins/genetics* ; Festuca/metabolism* ; Flowers/genetics* ; Gene Expression Regulation, Plant ; Photoperiod

The responsive patterns of phytochrome gene family members to photoperiod and abiotic stresses were comparatively analyzed and the favorable natural variation sites of these genes were identified. This would help understand the mechanism of phytochrome gene family in photoperiod-regulated growth and development and abiotic stress response. In addition, it may facilitate the molecular marker assisted selection of key traits in foxtail millet. In this study, we used RT-PCR to clone three phytochrome genes SiPHYA, SiPHYB and SiPHYC from ultra-late maturity millet landrace variety 'Maosu'. After primary bioinformatics analysis, we studied the photoperiod control mode and the characteristics of these genes in responding to five abiotic stresses including polyethylene glycol (PEG)-simulated drought, natural drought, abscisic acid (ABA), high temperature and NaCl by fluorescence quantitative PCR. Finally, we detected the mutation sites of the three genes among 160 foxtail millet materials and performed haplotype analysis to determine the genes' functional effect. We found that the cloned cDNA sequences of gene SiPHYA, SiPHYB and SiPHYC were 3 981, 3 953 and 3 764 bp respectively, which contained complete coding regions. Gene SiPHYB and SiPHYC showed closer evolutionary relationship. Photoperiod regulated all of the three genes, but showed more profound effects on diurnal expression pattern of SiPHYB, SiPHYC than that of SiPHYA. Under short-day, when near heading, the expression levels of SiPHYA and SiPHYB were significantly lower than that under long-day, indicating their roles in suppressing heading of foxtail millet under long-day. SiPHYB and SiPHYC were responsive to PEG-simulated drought, natural drought, ABA and high temperature stresses together. SiPHYA and SiPHYB responded differently to salt stress, whereas SiPHYC did not respond to salt stress. Re-sequencing of 160 foxtail millet materials revealed that SiPHYB was highly conservative. Two missense mutations of SiPHYA, such as single nucleotide polymorphism (SNP) 7 034 522^C→T and SNP7 036 657^G→C, led to delaying heading and increasing plant height. One missense mutation of SiPHYC, such as SNP5 414 823^G→T, led to shortening heading under short-day and delaying heading under long-day, as well as increasing plant height and panicle length regardless of photo-thermal conditions. Photoperiod showed different regulatory effects on SiPHYA, SiPHYB and SiPHYC. SiPHYB and SiPHYC jointly responded to various abiotic stresses except for the salt stress. Compared with the reference genotype, mutation genotypes of SiPHYA and SiPHYC delayed heading and increased plant height and panicle length.
Gene Expression Regulation, Plant ; Photoperiod ; Phytochrome/metabolism* ; Plant Proteins/metabolism* ; Setaria Plant/metabolism* ; Stress, Physiological/genetics*

PURPOSE: Stress, depending on its intensity and duration, results in either adaptive or maladaptive physiological and psychological changes in humans. Also, it was found that stressful experiences increase the signs of behavioral despair in rodents. On the other hand, exercise and melatonin treatment is believed to have many beneficial effects on health. Thus, this study was designed to evaluate the anti-depressant effects of physical activity and melatonin against chronic stress-induced depression in rats. METHODS: Adult male Sprague-Dawley(SD) rats(200-250g, 7 weeks of age) were subjected to depression induced by chronic stress. Chronic depression was induced with forced-swim stress (FSS) and repeated change of light-dark cycle for 4 weeks. In the last 2 weeks, some rats were confined in a cage enriched with a running wheel, seesaw and chewed a ball from 19:00 to 07:00 every day. Melatonin was injected intra-peritoneally (I.P), and the rats received intraperitoneal injections of melatonin (15 mg/kg). The Forced Swim Test (FST) was performed to evaluate the immobility behaviors of rats for a 5 min test. RESULTS: It was found that, the immobility time in FST was significantly (p<.05) lower in physical exercise (M=58.83+/-22.73) and melatonin (M=67.33+/-37.73) than in depressive rats (M=145.93+/-63.16) without physical activity. Also, TPH positive cell in dorsal raphe was significantly (p<.05) higher in exercise (M=457.38+/-103.21) and melatonin (M=425.38+/-111.56) than in depressive rats (M=258.25+/-89.13). CONCLUSION: This study suggests that physical activity and melatonin produces antidepressant-like effect on stress-induced depression in rats. So, physical exercise and melatonin may be a good intervention in depression patients.
Adult ; Animals ; Depression* ; Exercise ; Hand ; Humans ; Injections, Intraperitoneal ; Male ; Melatonin* ; Models, Animal* ; Motor Activity* ; Photoperiod ; Rats* ; Rodentia ; Running

BACKGROUND: The circadian rhythm of circulating melatonin is regulated by the endogenous oscillators, the suprachi-asmatic nuclei, and entrained by the light-dark cycle of the environment, but it seems that the rhythm can be affected by variable lesions outside the retina-pineal pathway. We intended to know how acute cerebral infarction affects on the cir-cadian rhythm of plasma melatonin secretion. METHODS: Plasma melatonin level was measured from 64 patients with acute cerebral infarction. On admission, blood samples were collected by venipuncture at 2AM, 4AM, 10AM, and 2PM and melatonin level was measured by radioimmunoassay. The state of consciousness of each patient was assessed clini-cally and the infarction site and size were evaluated clinically and radiographically. RESULTS: Among 64 patients with acute cerebral infarction, dramatic blunting or obliteration of nocturnal melatonin surge in the blood was found in 29 patients. The circadian rhythm of melatonin secretion was absent in 12 of 35 alert patients, in 10 of 20 drowsy patients, and in 5 of 7 stuporous patients. Melatonin secretion into plasma was markedly decreased in all 2 comatose patients. Of 14 patients with brainstem lesions, 8 patients showed decreased melatonin levels with the absence of a nocturnal rise, although most of them were alert. CONCLUSIONS: This study suggests that brainstem and the initial mental state might contribute to the regulation of the circadian rhythm of plasma melatonin even though the lesion does not involve the retina-pineal pathway, but further extensive study is required to elucidate it. (J Korean Neurol Assoc 19(4):359~363, 2001)
Biological Clocks ; Brain Stem ; Cerebral Infarction* ; Circadian Rhythm* ; Coma ; Consciousness ; Humans ; Infarction ; Melatonin* ; Phlebotomy ; Photoperiod ; Pineal Gland ; Plasma ; Radioimmunoassay ; Stupor

OBJECTIVES: This study was designed to test the hypothesis that delayed recovery from disrupted circadian rhythm is associated with both manic and depressive episodes in bipolar disorder. METHODS: Twenty-two male mice (age of five weeks, weight 28–30 gm) underwent three days of light-dark cycle disruption and 10 days of recovery phase. Sleep and wake state were checked every five minutes during the entire experimental period. After recovery phase, quinpirole (0.5 mg/kg, s.c.) was injected into the mice and open field locomotor activities were checked. Five days after the open field test, immobility time during the last 4 min in 6 min of forced swimming test was measured. Animals which recovered sleep-wake cycle within six days after light-dark cycle disruption were assigned to the early recovery group (n=14), and those that failed to recover in six days were assigned to the delayed recovery group (n=8). The locomotor activities and the immobility times of the two groups were compared by Mann-Whiney U test at two-tailed significance level of 0.05. RESULTS: The locomotor activities of the delayed recovery group were higher (mean rank=16.19) than those of the early recovery group (mean rank=8.82, U=18.5, p=0.008). The immobility times did not differ by recovery time (U=32.0 p=0.110). CONCLUSION: The results suggest that delayed recovery from circadian rhythm disruption raises the risk of manic symptoms rather than depressive symptoms.
Animals ; Animals* ; Bipolar Disorder ; Circadian Rhythm ; Depression ; Humans ; Male ; Mice* ; Models, Animal* ; Motor Activity ; Photoperiod ; Physical Exertion ; Quinpirole