The Clock gene clone and its circadian rhythms in Pelteobagrus vachelli

The Clock gene,a key molecule in circadian systems,is widely distributed in the animal kingdom. We isolated a 936-bp partial c DNA sequence of the C lock gene( Pva- clock) from the darkbarbel catfish P elteobagrus vachelli that exhibited high identity with C lock genes of other species of fish and animals(65%–88%). The putative domains included a basic helix-loop-helix(b HLH) domain and two period-ARNT-single-minded(PAS) domains,which were also similar to those in other species of fish and animals. P va- Clock was primarily expressed in the brain,and was detected in all of the peripheral tissues sampled. Additionally,the pattern of P va- Clock expression over a 24-h period exhibited a circadian rhythm in the brain,liver and intestine,with the acrophase at zeitgeber time 21:35,23:00,and 23:23,respectively. Our results provide insight into the function of the molecular C lock of P. vachelli.

Role of circadian gene Clock during differentiation of mouse pluripotent stem cells

Biological rhythms controlled by the circadian clock are absent in embryonic stem cells （ESCs）. However, they start to develop during the differentiation of pluripotent ESCs to downstream cells. Conversely, biological rhythms in adult somatic cells disappear when they are reprogrammed into induced pluripotent stem cells （iPSCs）. These studies indicated that the development of biological rhythms in ESCs might be closely associated with the maintenance and differentiation of ESCs. The core circadian gene Clock is essential for regulation of biological rhythms. Its role in the development of biological rhythms of ESCs is totally unknown. Here, we used CRISPR/CAS9-mediated genetic editing techniques, to completely knock out the Clock expression in mouse ESCs. By AP, teratoma formation, quantitative real-time PCR and Immunofluorescent staining, we did not find any dif- ference between Clock knockout mESCs and wild type mESCs in morphology and pluripotent capability under the pluripotent state. In brief, these data indicated Clock did not influence the maintaining of pluripotent state. However, they exhibited decreased proliferation and increased apoptosis. Furthermore, the biological rhythms failed to develop in Clock knockout mESCs after spontaneous differentiation, which indicated that there was no compensational factor in most peripheral tissues as described in mice models before （DeBruyne et ah, 2007b）. After spontaneous differentiation, loss of CLOCK protein due to Clock gene silencing induced spontaneous differentiation of mESCs, indicating an exit from the pluripotent state, or its differentiating ability. Our findings indicate that the core circadian gene Clock may be essential during normal mESCs differentiation by regulating mESCs proliferation, apoptosis and activity.

Recent advances on the circadian gene PER2 and metabolic rhythm of lactation of mammary gland

Due to regulation by circadian rhythm, the lactation of the mammary gland has rhythmicity. As one of prominent members of period protein family which regulates biological rhythms, PER2 plays an important role in developing the milk duct and maintaining the polarity and the morphology of the mammary epithelium; at the same time, it is also closely related with the metabolism of milk protein and milk fat. This paper summarized recent researches on PER2 gene and related researches on mammary gland development and metabolism to provide some information for the studies of the theory and technology on physiological functions of the mammary gland and milk quality control.

Organ-specific alterations in circadian genes by vertical sleeve gastrectomy in an obese diabetic mouse model

Current therapies for obesity and related complications have been shown to have limited benefits,including unsatisfactory weight loss and poor metabolic improvement.With recent developments in bariatric surgery,promising advancements have been made in clinical and scientific research,particularly in the management of obesity and diabetes.Vertical sleeve gastrectomy(VSG)has become increasingly popular due to its safety,simplicity,

Genes related to circadian rhythm are involved in regulating tuberization time in potato

Early tuberization,a short period from stolon occurrence to tuber formation,is one of the major characteristics of a good early-maturing potato cultivar,while the regulatory mechanism of tuberization time(TT)is still unclear.In this study,two tetraploid cultivars,Zhongshu 3(Z3)and Zhongshu 18(Z18),with short and long TT respectively,were examined to reveal regulatory genes related to TT using RNA sequencing of tissue samples taken during stolon occurrence,stolon swelling and tuber formation.Cluster analysis showed that the gene expression patterns at the stolon swelling and tuber formation stages were significantly different from those at stolon occurrence in both Z3 and Z18.Therefore,we screened the differentially expressed genes(DEGs)at stolon swelling and tuber formation and compared them to those at stolon occurrence.A total of 3085 DEGs were specifically identified and analyzed according to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment,and DEGs involved in starch and sucrose metabolism,plant hormone signal transduction and plant circadian clock were significantly enriched.The circadian clock genes were significantly differentially expressed between Z3 and Z18,revealing an important role for the plant circadian pathway in regulating TT.Furthermore,three candidate genes,StGI,StPRR and StEFM involved in circadian regulation and significantly differentially expressed between Z3 and Z18,were discovered and confirmed by qRT-PCR.The results provide valuable information for understanding the regulatory mechanisms of potato TT and represent a step toward breeding early-maturing potato cultivars.

Effects of 72 Hours Sleep Deprivation on Liver Circadian Clock Gene Expression and Oxidative Stress in Rats

Objective: To investigate the effects of 72 hours continuous sleep deprivation (SD) on circadian clock gene expression and oxidative stress in the rat liver. Methods: Twenty healthy male Sprague-Dawley rats were divided into 2 groups (n = 10 each) using a random number table: normal control group (group C), sleep deprivation group (group SD). Group SD was treated with a modified multiple platform water environment method. After 72 hours sleep deprived, the levels of AST (Aspartate transaminase ) and ALT (Alanine aminotransferase) in serum were determined. The contents of malondialdehyde (MDA), the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the liver tissue of the rats were examined in both two groups. The expression levels of CLOCK, BMAL1 and CRY1 protein in liver tissue were examined by Western blotting. Results: Compared with group C, the content of MDA, and the levels of AST and ALT in serum were significantly increased (P Conclusion: 72 hours continuous sleep deprivation can downregulate the expression of circadian clock gene and promote oxidative stress in rats.

Effect of Xiaoaiping on the expression of circadian clock genes in human hepatoma HepG2 cells

Objective： Investigation of the effect of Xiaoaiping on the expression of circadian clock genes in human hepatoma HepG2 cells. Methods： Selecting the HepG2 cells in the logarithmic growth phase and assigning them to Xiaoaiping injection （XAP） group and control group. The two groups were treated with 75 mg/mL XAP or the same dose of normal saline. After 72 h of treatment, real-time PCR was used to detect the expression of circadian clock genes in HepG2 cells and Western Blot technology was used to detect the expression of related proteins. Results： The mRNA expression levels of PER1, NPAS2, NR1D1, and DEC1 in the XAP group was significantly higher than that in the control group （P〈 0.05）, while the mRNA expression levels of PER3, BMAL1, DEC2, and RORA were significantly lower in the XAP group than in the control group （P 〈 0.05）, and there was no significant difference between the mRNA expression levels of PER2, CRY1, CRY2, and TIM. Of course, the proteins＇ expression levels of the genes we had detected such as PERle3, CRYI-2, CLOCK, BMAL1 by Western Blot were consistent with the real-time PCR results above. Conclusion： XAP affects the expression of circadian clock genes in HepG2 cells.

Molecular insights into the circadian clock in marine diatoms

The circadian clock is a fundamental endogenous mechanism of adaptation that coordinates the physiology and behavior of most organisms with diel variations in the external environment to maintain temporal homeostasis.Diatoms are the major primary producers in the ocean.However,little is known about the circadian clock in marine diatoms compared with other organisms.Here,we investigated circadian clock genes,their expression patterns,and responses to environmental stimuli such as light,nitrogen and phosphorus in two marine diatoms,Skeletonema costatum and Phaeodactylum tricornutum,using a combination of q RT-PCR and bioinformatic analysis.We identified 17 and 18 circadian clock genes in P.tricornutum and S.costatum,respectively.Despite significant evolutionary differences,these genes were similar to those of the higher plant Arabidopsis.We also established a molecular model for the marine diatom circadian clock comprising an input pathway,core oscillator,output pathway,and valve effector.Notably,the expression patterns of core clock genes(circadian clock associated 1(CCA1),late elongated hypocotyl(LHY)and timing of cab 1(TOC1))in both species differed from those of terrestrial plants.Furthermore,the expression of these genes was influenced by variations in ambient light,nitrogen and phosphorus availability.Although marine diatoms and higher plants share common circadian clock components,their clock genes have diverged throughout evolution,likely as a result of adapting to contrasting environments.

circadian clock circuitry in colorectal cancer

Colorectal cancer is the most prevalent among digestive system cancers.Carcinogenesis relies on disrupted control of cellular processes,such as metabolism,proliferation,DNA damage recognition and repair,and apoptosis.Cell,tissue,organ and body physiology is characterized by periodic fluctuations driven by biological clocks operating through the clock gene machinery.Dysfunction of molecular clockworks and cellular oscillators is involved in tumorigenesis,and altered expression of clock genes has been found in cancer patients.Epidemiological studies have shown that circadian disruption,that is,alteration of bodily temporal organization,is a cancer risk factor,and an increased incidence of colorectal neoplastic disease is reported in shift workers.In this review we describe the involvement of the circadian clock circuitry in colorectal carcinogenesis and the therapeutic strategies addressing temporal deregulation in colorectal cancer.

Effects of Chronotherapy of Benazepril on the Diurnal Profile of RAAS and Clock Genes in the Kidney of 5/6 Nephrectomy Rats

Summary： This study investigated the effects of benazepril administered in the morning or evening on the diurnal variation of renin-angiotensin-aldosterone system （RAAS） and clock genes in the kidney. The male Wistar rat models of 5/6 subtotal nephrectomy （STNx） were established. Animals were ran- domly divided into 4 groups： sham STNx group （control）, STNx group, morning benazepril group （MB） and evening benazepril group （EB）. Benazepril was intragastfically administered at a dose of 10 mg/kg/day at 07：00 and 19：00 in the MB group and EB group respectively for 12 weeks. All the animals were synchronized to the light：dark cycle of 12：12 for 12 weeks. Systolic blood pressure （SBP）, 24-h urinary protein excretion and renal function were measured at 11 weeks. Blood samples and kidneys were collected every 4 h throughout a day to detect the expression pattern of renin activity （RA）, angio- tensin Ⅱ （Ang Ⅱ ） and aldosterone （Aid） by radioimmunoassay （RIA） and the mRNA expression profile of clock genes （bmall, dbp and per2） by real-time PCR at 12 weeks. Our results showed that no signifi- cant differences were noted in the SBP, 24-h urine protein excretion and renal function between the MB and EB groups. There were no significant differences in average Aid and RA content of a day between the MB group and EB group. The expression peak of bmall mRNA was phase-delayed by 4 to 8 h, and the diurnal variation of per2 and dbp mRNA diminished in the MB and EB groups compared with the control and STNx groups. It was concluded when the similar SBP reduction, RAAS inhibition and clock gene profile were achieved with optimal dose of benazepril, morning versus evening dosing of benazepril has the same renoprotection effects.

柴胡皂苷A调节cAMP/PKA/CREB信号通路对失眠大鼠的改善作用及机制研究

目的基于cAMP/PKA/CREB通路探讨柴胡皂苷A对失眠大鼠的改善作用及机制。方法将75只SD大鼠随机分为空白组、模型组、柴胡皂苷A低剂量组(0.625 mg·kg^(-1))、柴胡皂苷A高剂量组(2.500 mg·kg^(-1))、艾司唑仑组(0.1 mg·kg^(-1)),每组15只。采用腹腔注射苯丙氨酸(PCPA,0.1 mg·kg^(-1))复制失眠大鼠模型。观察大鼠一般情况及昼夜节律;采用戊巴比妥钠翻正实验测定大鼠睡眠潜伏期及睡眠持续时间;观测大鼠睡眠时相,记录慢波睡眠第1期(SWS1)、慢波睡眠第2期(SWS2)、快速眼球运动睡眠期(REMS)时长以及总睡眠时长(TST);qRT-PCR法测定下丘脑节律基因Clock、Bmal1 mRNA及钟控基因Rev-erbα、RorαmRNA的表达水平;免疫荧光法测定海马组织NeuN表达水平;ELISA法测定脑组织中的cAMP水平;Western Blot法测定脑组织中Clock、Bmal1、Rev-erbα、Rorα及cAMP/PKA/CREB通路相关蛋白表达水平。结果与空白组比较,模型组大鼠昼伏夜出的节律紊乱,极度兴奋,易激惹,睡眠减少;睡眠潜伏期明显延长(P<0.05),睡眠持续时间及SWS1、SWS2、REMS、TST均明显缩短(P<0.05);神经元排列紊乱,NeuN阳性神经元IOD值明显降低(P<0.05);脑组织Clock、Bmal1、Rev-erbα、RorαmRNA及蛋白表达水平明显降低(P<0.05);脑组织cAMP、p-PKA/PKA、p-CREB/CREB蛋白表达水平明显降低(P<0.05)。与模型组比较,给药组大鼠的攻击性明显减弱,昼伏夜出有节律性,活动减少,睡眠增多;睡眠潜伏期明显缩短(P<0.05),睡眠持续时间及SWS1、SWS2、REMS、TST均明显延长(P<0.05);神经元排列紊乱情况有所恢复,NeuN阳性神经元IOD值明显升高(P<0.05);脑组织Clock、Bmal1、Rev-erbα、RorαmRNA及蛋白表达水平明显升高(P<0.05);脑组织cAMP、p-PKA/PKA、p-CREB/CREB蛋白表达水平明显升高(P<0.05)。结论柴胡皂苷A可能通过激活cAMP/PKA/CREB通路改善失眠大鼠的昼夜节律。

Hypoxia-inducible factor-1αin myocardial infarction

Hypoxia-inducible factor 1(HIF1)has a crucial function in the regulation of oxygen levels in mammalian cells,especially under hypoxic conditions.Its importance in cardiovascular diseases,particularly in cardiac ischemia,is because of its ability to alleviate cardiac dysfunction.The oxygen-responsive subunit,HIF1α,plays a crucial role in this process,as it has been shown to have cardioprotective effects in myocardial infarction through regulating the expression of genes affecting cellular survival,angiogenesis,and metabolism.Furthermore,HIF1αexpression induced reperfusion in the ischemic skeletal muscle,and hypoxic skin wounds in diabetic animal models showed reduced HIF1αexpression.Increased expression of HIF1αhas been shown to reduce apoptosis and oxidative stress in cardiomyocytes during acute myocardial infarction.Genetic variations in HIF1αhave also been found to correlate with altered responses to ischemic cardiovascular disease.In addition,a link has been established between the circadian rhythm and hypoxic molecular signaling pathways,with HIF1αfunctioning as an oxygen sensor and circadian genes such as period circadian regulator 2 responding to changes in light.This editorial analyzes the relationship between HIF1αand the circadian rhythm and highlights its significance in myocardial adaptation to hypoxia.Understanding the changes in molecular signaling pathways associated with diseases,specifically cardiovascular diseases,provides the opportunity for innovative therapeutic interventions,especially in low-oxygen environments such as myocardial infarction.

生物钟基因Bmal1、Per2在血液肿瘤细胞株Raji、Hut-78、OCI-LY8及HL-60中的昼夜表达规律

目的通过检测生物钟基因Bmal1、Per2在血液肿瘤细胞株Raji、Hut-78、OCI-LY8及HL-60细胞中不同时间点的mRNA表达情况,探讨其与血液肿瘤发生发展的可能关系。方法血液肿瘤细胞株Raji、Hut-78、LY-8、HL-60经血清休克法诱导节律后,RT-PCR法检测生物钟基因Bmal1及Per2在不同时间点的mRNA转录水平,以时间为变量分别对其转录量进行余弦函数拟合,通过余弦函数预测基因转录高峰及低谷时段。结果Bmal1和Per2基因表达在OCI-LY8、Hut-78、HL-60细胞中呈现昼夜节律(P<0.05);Raji细胞内Bmal1基因无节律性表达(P>0.05),而Per2基因呈昼夜节律表达(P<0.05)。结论生物钟基因Per2和(或)Bmal1在多种血液肿瘤细胞株内呈昼夜节律性表达,其可能参与血液肿瘤的发生发展。

生物节律与子痫前期的相关性

子痫前期(preeclampsia,PE)是一种常见的妊娠并发症,危害母婴健康,更是一个严重的国际公共卫生问题。尽管已证实PE的高危因素包括肥胖、糖尿病和妊娠前高血压等,但其发病机制仍未完全阐明。哺乳动物中绝大多数的生理过程由生物节律调控,生物节律的破坏被证实与众多疾病相关,如心血管疾病、糖尿病和乳腺癌等。尽管PE具有一系列时间生物节律的特征性表现,如PE患者的血压24 h节律变异性、“反勺状”血压与更严重的靶器官损伤有关、夜间服用阿司匹林的预防保护作用更优异等,但生物节律的变异是否为PE的危险因素,抑或PE本身是否与异常的生物节律相关,目前尚未明确。综述生物节律与PE的相关性,包括胎盘的钟基因表达及其与PE的关系、血压的生物节律、PE预防的时间治疗学、生物节律的破坏与PE风险性,以启示今后深入研究生物节律/钟基因与PE之间潜在关联的必要性。

摩腹联合电针透穴法对失眠大鼠生物钟相关基因及神经递质表达的影响

目的探讨摩腹联合电针透穴法对失眠大鼠生物钟基因Clock、BMAL1、PER1表达及神经递质乙酰胆碱(ACh)、谷氨酸(Glu)含量的影响及可能的作用机制。方法50只SD雄性大鼠随机分为正常组、模型组、摩腹组、电针透穴组和联合组,每组10只。除正常组外,采用腹腔注射对氯苯丙氨酸建立失眠大鼠模型。摩腹组进行腹部按摩,电针透穴组采用平刺法,百会透神庭、三阴交透阴陵泉(双侧)、神门透内关(双侧),电针仪疏密波,频率1Hz/20Hz,联合组摩腹后进行电针透穴治疗,各组均1次/d,连续7d,正常组和模型组不予干预。HE染色观察下丘脑组织神经元细胞形态变化,RT-qPCR检测下丘脑组织Clock、BMAL1、PER1 mRNA表达,免疫组化染色检测下丘脑组织Clock、BMAL1、PER1表达,Western blot检测下丘脑组织Clock、BMAL1、PER1蛋白表达,ELISA检测血清ACh、Glu含量。结果与正常组比较,模型组大鼠入睡潜伏期延长,睡眠持续时间缩短,下丘脑组织细胞结构破坏严重、呈空泡样变化,神经元细胞数量减少,下丘脑组织Clock、BMAL1mRNA和蛋白表达升高,PER1mRNA和蛋白表达降低,血清ACh、Glu含量增加,差异均有统计学意义(P<0.05);与模型组比较,摩腹组、电针透穴组和联合组均能缩短入睡潜伏期,延长睡眠持续时间,改善下丘脑神经元细胞形态,降低下丘脑组织Clock、BMAL1mRNA和蛋白表达,上调PER1mRNA和蛋白表达,减少血清ACh、Glu含量,差异均有统计学意义(P<0.05),以联合组作用最显著(P<0.05)。结论摩腹联合电针透穴法能改善大鼠失眠状况,其机制可能与调控生物钟基因Clock、BMAL1、PER1mRNA和蛋白表达及神经递质含量有关。

生物钟基因调控妊娠并发症及其对子代发育的影响

母体的昼夜节律信号与生物钟基因相互作用可以影响胎盘及胎儿的发育,引发妊娠期糖尿病、子痫前期、流产、早产、子代发育异常等结局。该文综述了生物钟基因与母体、胎盘及胎儿之间的联系,以及如何诱导母胎界面不良妊娠结局的发生,从而预测相关风险对子代的影响,提高临床妊娠并发症的风险管理和疾病控制及预防方案的准确性,为人类生殖健康提供重要指引。

时钟基因调控低氧训练肥胖大鼠白色脂肪组织棕色化

背景:低氧训练可以促进机体脂肪的降解,外界环境变化可影响动物昼夜节律,但昼夜节律变化对脂肪组织棕色化及脂肪降解的调控机制尚不明确。目的:阐明时钟基因对低氧训练大鼠附睾脂肪组织棕色化的调控机制。方法:喂养高脂饲料构建肥胖大鼠模型,造模成功后抽取40只肥胖大鼠随机分为4组,即常氧安静组、低氧安静组、常氧训练组、低氧训练组,每组10只,进行4周的干预。安静组大鼠不实施干预;低氧组大鼠全天生活在氧浓度为13.6%的低氧仓中;训练组第1周为适应性训练,后3周训练速度和时长保持不变。测量肥胖大鼠体质量、体长和肾周脂肪质量;并使用血脂生化检测试剂盒检测肥胖大鼠血清中三酰甘油、总胆固醇、低密度脂蛋白胆固醇以及高密度脂蛋白胆固醇水平;油红O染色观察肝脏脂肪含量变化;苏木精-伊红染色评价各组大鼠附睾脂肪组织棕色化变化;转录组测序技术结合生物信息学分析脂肪组织中转录组水平变化;采用qRT-PCR检测附睾脂肪组织中PGC-1α、Beclin1、KLF2、Perilipin1 mRNA的表达变化情况。结果与结论:①低氧训练干预使营养性肥胖大鼠体质量、脂体比、Lees’s指数、血清总胆固醇、三酰甘油以及低密度脂蛋白胆固醇浓度显著降低(P<0.01),高密度脂蛋白胆固醇浓度显著升高(P<0.01);②油红O染色和苏木精-伊红染色显示,相比于常氧安静组、低氧安静组和常氧训练组,低氧训练更能有效促进大鼠肝脏组织中脂肪动员和附睾旁脂肪组织棕色化;③转录组测序结果显示,低氧训练时钟基因Dbp、Nr1d1、Sik1以及脂肪组织棕色化基因Ppargc1a(PGC-1α)等表达显著上调(P<0.05),而Arntl(Bmal1)显著下调(P<0.05),同时伴随物质代谢相关基因的表达增强;④qRT-PCR结果证实低氧训练时脂肪组织棕色化基因PGC-1α和脂代谢基因Perilipin1表达量均显著升高(P<0.01);⑤结果证实时钟基因在低氧训练促进脂肪组织棕色化过程中起到重要作用。

改善昼夜节律紊乱减轻糖尿病大鼠心肌缺血/再灌注损伤

目的 探讨间断补充睡眠能否减轻昼夜节律紊乱加重的糖尿病大鼠心肌缺血/再灌注损伤。方法 给大鼠腹腔注射1%链脲佐菌素(STZ)30 mg/kg及高脂高糖饮食构建糖尿病模型。造模成功的40只糖尿病大鼠,随机分为4组,每组10只:假手术组(Sham组)、缺血/再灌注组[I/R组,结扎左冠状动脉前降支(LDA)30 min,再灌注120 min]、昼夜节律紊乱组(Crd组,每日持续24 h光照并提供食物)、间断补充睡眠组(Dss组,夜间每光照3 h关闭1.5 h补充睡眠)。三苯基四氮唑(TTC)染色法计算心肌梗死体积;ELISA测定血清中肌酸激酶同工酶(CK-MB)活性、肌钙蛋白Ⅰ(cTnⅠ)含量;Western blot测定心肌生物钟基因Bmal1、Rev-erbα的表达量。结果 与Sham组相比,I/R组心肌梗死体积明显增大,血清CK-MB活性和cTnⅠ含量明显升高,心肌组织Bmall表达下调,Rev-erbα上调(P<0.05);与I/R组相比,Crd组心肌梗死体积增大,血清CK-MB活性和cTnⅠ含量升高,心肌组织钟基因Bmal1表达下调、Rev-erbα表达上调(P<0.05);与Crd组相比,Dss组心肌梗死体积减小,血清cTnⅠ含量和CK-MB活性降低,钟基因Bmal1表达上调、Rev-erbα表达下调(P<0.05)。结论 间断补充睡眠可减轻由昼夜节律紊乱加重的糖尿病大鼠心肌缺血/再灌注损伤。

华南鲤昼夜摄食节律与agrp基因表达水平相关性研究

鱼类的摄食节律表现出种间甚至种内差异。为阐明华南鲤(Cyprinus carpio rubrofuscus)的昼夜摄食节律,为其室内标准化养殖方法的建立提供科学依据,研究了在自然光照下华南鲤的昼夜摄食节律以及刺鼠相关蛋白(Agouti-related protein,AgRP)基因表达水平与摄食昼夜节律的关系。采用分段连续投喂的方法对春分和秋分时节广州地区华南鲤的昼夜摄食量进行测定,运用实时荧光定量PCR(Quantitative real-time PCR,qRT-PCR)技术检测agrp基因在华南鲤脑、前肠、中肠和后肠中的昼夜表达节律特点。结果显示,春分和秋分时节华南鲤摄食量有相似的昼夜节律。春分时华南鲤的摄食量在8:00最低,分别在12:00和24:00出现摄食高峰;秋分时华南鲤的摄食量也在8:00最低,分别在12:00和20:00出现摄食高峰。qRT-PCR结果表明,agrp1和agrp2基因的表达量都具有昼夜节律。agrp1和agrp2在脑中的表达量分别在8:00和20:00最高,24:00和4:00最低。agrp1基因在前肠、中肠和后肠的表达量分别在16:00、20:00和24:00最高,8:00最低;agrp2基因在前、中、后肠的表达量分别在16:00、24:00、24:00最高,在12:00、4:00、20:00最低。综上,华南鲤摄食量最低时agrp1基因在脑中的表达量最高以促进后续摄食行为,在2次摄食高峰之间(12:00—20:00)agrp1基因在前、中、后肠的表达量依次出现最高点,其变化趋势与食物在肠道中的运动过程一致,推测agrp1基因可能参与了华南鲤摄食昼夜节律的调控;而agrp2基因的表达水平与摄食节律无相关的变化趋势,推测agrp2基因在进化过程中可能出现了功能分化。