• 한국발생생물학회지:발생과생식
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• 제17권3호
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• pp.149-177
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• 2013

Living beings are surrounded by various changes exhibiting periodical rhythms in environment. The environmental changes are imprinted in organisms in various pattern. The phenomena are believed to match the external signal with organisms in order to increase their survival rate. The signals are categorized into circadian, seasonal, and annual cycles. Among the cycles, the circadian rhythm is regarded as the most important factor because its periodicity is in harmony with the levels of melatonin secreted from pineal gland. Melatonin is produced by the absence of light and its presence displays darkness. Melatonin plays various roles in creatures. Therefore, this review is to introduce the diverse potential ability of melatonin in manifold aspects in living organism.

• 수면정신생리
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• 제4권2호
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• pp.147-155
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• 1997

이제까지 제시된 수면/각성과 관련된 연구의 결과들이 아직은 부족하거나 일관성이 결여되어 있기 때문에 인간의 수면/각성 리듬에 대한 모텔은 확립되지 않았다. 주 수면시간, 서파 수면, 렘수면, 수면의 깊이, 아침에 깨어남, 각성 수준 등의 주 리듬은 일중리듬을 보여준다. 주 수면시간은 중심체온과 이전의 깨어있는 기간에 의해 결정되는 것으로 알려져 있다. 렘수면 발생의 경향은 통상적인 아침 기상시간 이후 오전 내내 높은 수준으로 남아있게 된다. 수면경향이 갖는 일중 반주기의 내인성 생물학적 특성은 모든 연령에서 독특하게 보여지는 현상이다. 오후의 졸리움이나 수면에 대한 증거는 수면잠복기 반복검사, 수면연장 연구, 비동승상태 연구, 자유질주 연구 등과 같은 여러 연구방법에서 보여진 오후의 졸리움, 수행능력, 다양한 수면장애의 병리적 특성, 그리고 시에스타 문화에서 증명된다. 일중 12 시간 수면리듬의 모델은 아직도 일중 반주기 리듬이 일중리듬이 고유한 이형식의 리듬으로 표현되는 것인지 아니면 별개의 독립적 인 현상인지에 대한 결론이 내려지지 않았기 때문에 확립되지 않았다. 수면-각성의 주기에는 하루에 3-4회, 즉 6-8 시간의 주기를 갖는 중간 단주기 리듬이 내재되어 있고, 또 성인의 야간수면은 90-120 분의 주기를 갖는 비-램 수면과 렘수면의 리듬미칼한 극단 주기적 교대를 보여준다. 그뿐 아니라 주간의 기본적인 휴식 -활동 주기는 야간의 렘 수면주기에 상응한다는 가설이 제시되기도 하였다. 수면의 단주기 리듬에 대한 연구는 전통적인 수면다원 검사, 낮잠 연구, 휴식 및 일상지속법 연구, 수면연장 연구, 보행감찰, 극 초단적 수면일정, 시간격리연구 등을 통해 시행되고 있다. 내재하는 다양한 신체의 리듬들이 어떻게, 또 어느 정도 상호작용하여 수면의 시작과 종결을 조절하며, 반일주기 수면경향의 본질은 어떠하고, 또 렘 주기와 수면과의 관계는 어떠한가에 대한 의문은 앞으로 해결해야 할 중요한 쟁점들이다.

• 한국수산과학회지
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• 제50권5호
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• pp.534-540
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• 2017

This study was conducted to determine the circadian rhythm and the effect of starvation for the health assessment of olive flounder Paralichthys olivaceus, reared under 12:12 LD (light:dark) cycle and fed 1% of their body weight once a day. The blood collection was implemented from 10 fish every 3 hours for a day, and analyzed to serval health parameters of the experimental fish. Plasma cortisol, glucose and total protein concentration reflected diel rhythms with high level of photophase and low level of scotophse despites of glutamic oxalacetic transaminase (GOT) and glutamic pyruvate transaminase (GPT) showing no rhythmicity, while electrolyte (sodium, potassium and chloride ion) concentrations arrived at the peak 18 hour and then slowly down. In the experiment of starvation, the result showed that there were no significant differences of the health parameters between the starved group and the fed. In short, our findings described the existence of circadian cortisol with glucose in flat fish, and indicated that the starvation does not almost affect the health of fish.

• 한국환경보건학회지
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• 제27권2호
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• pp.10-16
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• 2001

To evaluate an effect of circadian variation on the xylene metabolizing enzyme activities, 50% m-xylene in olive oil(0.25 $m\ell$/100g body weight) was intraperitoneally administered to the rats every other day for 6 days both in the night; 24:00 and the day; 12:00. Then animals were sacrigiced at 8hr after last injection of m-xylene. Hepatic microsomal cytochrome p450 contents were more increased both in control and xylene treated rats of night phase than those of day phase. But the activity of hepatic alcohol dehydrogenase(ADH) in control of night phase showed the similar value with that in those of day phase and xylene treated rats of day phase showed an increasing tendency of hepatic ADH activity as those of night phase showing similar activity. Furthermore, control rats of night phase than those of day phase. And by xylene treatment, enzyme activities of rats of day phase were higher tendency in rats of control but those of night phase were somewhat inhibited. Besides, xylene-treated animals of night phase showed increasing tendency of urinary methylhippuric acid concentration compared with those of day phase. On the other hand, liver weight per body weight(%), hepatic lipid peroxide content and serum xanthine oxidase activity were higher in night phase. And the activities of hepatic oxygen free radical metabolizing enzymes such as xanthine oxidase, gluthathione S-transferase, and xylene-treated rats of night phase than those of day phase. In conclusion, it can be hypothesized on the basis of the results that the accumulation rate of m-xylene intermediate metabolite, i.e. m-methylbenzaldehyde in liver tissus may be higher in night phase than in day phase and it may be responsible for higher liver toxicity in bight phase than in day phase.

• Animal cells and systems
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• 제16권5호
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• pp.357-365
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• 2012

We have examined the effect of circadian disturbances induced by night shifts (NSs) on the phenotypes of the tibiae and abdominal adipose tissues (ADTs) in a mouse model by using in vivo micro-computed tomography (micro-CT). We found that the volumes of total and visceral ADTs in the night-shifted group of mice were significantly larger (69 and 92%, respectively) than those in the control. The mean polar moment of inertia, cross-sectional thickness, and bone mineral density of the cortical bone in the night-shifted group of mice were less (13, 5, and 3%, respectively) than those in the control. Moreover, the volume and the thickness of growth plates (GPs) of the tibiae in the night-shifted mice were significantly smaller (22 and 20%, respectively) than those in the control. Taken together, our results indicate that disturbances in the mouse circadian rhythms induced by NSs affect the morphological characteristics of cortical bone, the volume and the thickness of GPs, and the volume of ADTs.

• 대한인간공학회지
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• 제19권3호
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• pp.1-12
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• 2000

The Korean version of the morningness-eveningness questionnaire (MEQ) and sleep habits inventory were administered to 1,038 Korean male daytime workers and were analyzed according to age and chronotype to determine what these factors reveal about sleep habits in view of phase difference of circadian rhythm. The mean and distribution of scores on the MEQ moved significantly toward the morning type with aging. Bedtimes and waking times were progressively later from the morning, intermediate, to evening types, and were also earlier with aging. Preferred bedtimes and waking times showed more distinct differences than did the habitual times in each chronotype. The percentage of subjects who answered that sleep length was 'short', mood upon waking was 'bad', and variabilities of bedtime and sleep length were 'large' were greater in the young and evening types than in the elder and morning types, respectively. These findings suggested that subjects were shifted toward the morning type and the phase of circadian rhythm had moved forward with aging. Preferred bedtime and waking time were a better reflection of individual circadian rhythms than habitual bedtime and waking time.

• BMB Reports
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• 제50권5호
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• pp.235-236
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• 2017

The circadian clock is an internal system that is synchronized by external stimuli, such as light and temperature, and influences various physiological and developmental processes in living organisms. In the model plant Arabidopsis, transcriptional, translational and post-translational processes are interlocked by feedback loops among morning- and evening-phased genes. In a post-translational loop, plant-specific single-gene encoded GIGANTEA (GI) stabilize the F-box protein ZEITLUPE (ZTL), driving the targeted-proteasomal degradation of TIMING OF CAB EXPRESSION 1 (TOC1) and PSEUDO-RESPONSE REGULATOR 5 (PRR5). Inherent to this, we demonstrate the novel biochemical function of GI as a chaperone and/or co-chaperone of Heat-Shock Protein 90 (HSP90). GI prevents ZTL degradation as a chaperone and facilitates ZTL maturation together with HSP90/HSP70, enhancing ZTL activity in vitro and in planta. GI is known to be involved in a wide range of physiology and development as well as abiotic stress responses in plants, but it could also interact with diverse client proteins to increase protein maturation. Our results provide evidence that GI helps proteostasis of ZTL by acting as a chaperone and a co-chaperone of HSP90 for proper functioning of the Arabidopsis circadian clock.

• Biomolecules & Therapeutics
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• 제19권3호
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• pp.308-314
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• 2011

It has been shown that circadian genes not only play an important role on circadian rhythms, but also participate in other physiological and pathological activities, such as drug dependence, cancer development and radiation injury. The Per2, an indispensable component of the circadian clock, not only modulates circadian oscillations, but also regulates organic function. In the present study, we applied mPER2-upregulated NIH3T3 cells to reveal the relationship of mPer2 and the cells damaged by ultraviolet C (UVC). NIH3T3 cells at the peak of the expression of mPer2 induced by phorbol 12-myristate 13-acetate (PMA) demonstrated little damage by UVC evaluated by MTT assay, cell growth curves and cell colony-forming assay, compared with that at the nadir of the expression of mPer2. Overexpression of mPER2, accompanied p53 upregulated, also demonstrated protective effect on NIH3T3 cells damaged by UVC. These results suggest that mPer2 plays a protective effect on cells damaged by UVC, whose mechanism may be involved in upregulated p53.

• 대한간호학회지
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• 제24권2호
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• pp.175-189
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• 1994

This study examined the daily rhythmic patterns of mood in shift workers. Ten rotating shift nurses (shift worker group) were matched with ten non-rotating student nurses (non - shift worker group) working under the same conditions at University Hospital. The subjects completed the Mood Adjective Checkist (MAC) every two or three hours from 6AM to 9-11 PM for six consecutive days. The MAC was constructed by Mansour and conversed the mood factors of Anger - Depression. Happiness, Mental, and Social. These data were analyzed by using Cosinor method. The results are summarized as follows : 1. There was no difference in mean scores for Anger - Depression, Happiness, Mental, and Social mood rhythm between the shift workers and the non - shift workers. 2. There was no difference in the amplitude of Anger - Depression, Happiness and Social mood between the two groups, but the shift workers had a higher amplitude of Mental mood. 3. The acrophases of the Anger - Depression mood were between 1:28 and 2:05, and those of Happiness, Social, and Mental mood were between 12:5 and 15:03 for both groups. There were no differences between the groups. 4. The number of the subjects with statistically significant mean cosinor rhythms for Anger-De-pression and Mental moods were higher in the shift workers than in the non-shift workers, but there were no differences between the shift workers and the non-shift workers in those of Happiness and Mental mood. This study showed that the mod manifested circadian periodicities, and a rapidly rotating shift system did not changed the circadian rhythm of mood. It is expected that this study will facilitate a better understanding of circadian rhythm in mood in the shiftworkers.

• 생명과학회지
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• 제27권10호
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• pp.1225-1231
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• 2017

암을 포함한 다양한 인간의 질병 발생이 circadian clock 유전자의 변형된 발현 양상과 깊은 연관관계를 나타내고 있다. 세포 주기와 세포 성장은 circadian rhythm과 연결되어 있으며, 이를 조절하는 clock 유전자의 비정상적인 발현은 결국 종양 발생과 암의 발달을 유발하게 된다. Circadian clock에 관한 분자적 기전은 다수의 clock activator와 clock repressor의 통합적인 조절에 따른 전사 및 번역이 포함된 음성피드백 고리로 구성되어 있다. 이러한 circadian rhythm의 자동조절 기전에 의해 전체 유전체의 약 10~15%가 전사 수준에서 영향받는 것으로 나타났다. 많은 clock 유전자들 중, Period 1 (Per1)과 Period 2 (Per2)는 clock repressor 유전자로 정상적인 생리적 리듬을 조절하는 것에 기여한다. PER1과 PER2는 cyclin, CDK, CKI를 포함하는 세포 주기 조절자의 발현에 관여함이 밝혀졌으며, 다양한 암에서 PER1과 PER2의 발현 감소가 보고되었다. 따라서, 본 논문에서는 PER1과 PER2의 circadian rhythm에서의 분자적 기능과 종양 발생과 관련된 PER1과 PER2의 하위 표적인자에 대해 살펴보고, 암 치료를 위한 새로운 치료 표적과 암의 예후를 예측하기 위한 분자 지표로써의 PER1과 PER2의 가능성에 대해 서술하고자 한다.