CAT1基因在尼罗罗非鱼肌肉和肝的节律性表达研究

Study on the Rhythmic Expression of CAT1 Gene in the Muscle and Liver of Nile tilapia

为了探究碱性氨基酸转运载体(CAT1)基因在尼罗罗非鱼(Oreochromis niloticus)饥饿0、7 d肌肉和肝的昼夜表达规律,实验分别在尼罗罗非鱼饥饿0,7 d 06:00、09:00、12:00、15:00、18:00、21:00和24:00、第2天03:00、06:00,分别对应区时(Zone time,ZT)ZT0、ZT3、ZT6、ZT9、ZT12、ZT15、ZT18、ZT21、ZT24采样,采样在一昼夜内完成。每组随机取3尾鱼进行解剖,取其肌肉和肝样品分析。结果表明:CAT1基因在正常投喂的尼罗罗非鱼肌肉表达具有显著性时间差异(p<0.05),呈现昼低夜高的节律性振荡(p<0.3),达到峰值的时间为ZT 0.72。饥饿7 d后,虽然在各时间点上CAT1基因表达有显著性差异(p<0.05),但无昼夜节律性(p>0.3);CAT1基因表达为在光周期先升后降,在暗周期先降后升,峰值相位在光照阶段,为ZT 7.44。在尼罗罗非鱼肝中,CAT1基因在正常投喂时表达具有显著性时间差异(p<0.05),呈现节律性振荡(p<0.3),CAT1基因表达为在光周期先降后升,在暗周期则先升后降,峰值相位在黑暗阶段,达到峰值的时间为ZT 16.56。饥饿7 d后,在各时间点上CAT1基因表达无显著性时间差异(p>0.05),且表达无昼夜节律性(p>0.3);CAT1基因表达为在光周期先降后升,在暗周期则先升后降,峰值相位在黑暗阶段,为ZT 21.60。以上结果说明CAT1基因在尼罗罗非鱼肌肉和肝表达的昼夜节律不同。

The circadian expression of alkaline amino acid transporters(CAT1)gene in the muscle and liver of tilapia(Oreochromis niloticus)was studied under the 12 h-light and 12 h-dark(LD)cycle condition.Muscles and liver of tilapia(Oreochromis niloticus)were collected at ZT0(06:00),ZT3(09:00),ZT6(12:00),ZT9(15:00),ZT12(18:00),ZT15(21:00),ZT18(24:00),ZT21(03:00,2 nd day),ZT24(06:00,2 nd day)(Zone time,ZT)with three fishes at each time point.The samples were analyzed and the main results were that the expression of CAT1 gene showed significant time difference(p<0.05)in the muscle of tilapia at initial.The rhythm oscillation(p<0.3)showed was low in the daytime and high at night,in which the peak time was ZT 0.72.Although there were significant differences at different time points(p<0.05)after the fish were starved for 7 days,there was no circadian rhythm(p>0.3).The expression of CAT1 gene increased first and then decreased during the light cycle,however,the expression of CAT1 gene decreased first and then elevated during the dark period,in which the peak phase was in the illumination stage,ZT 7.44.In the liver of tilapia,the expression of CAT1 gene showed significant time difference(p<0.05)and rhythmic oscillation(p<0.3)at initial.The expression of CAT1 gene decreased first and then elevated during the light cycle,however,the expression of CAT1 gene increased first and then decreased during the dark period,in which the peak phase was in the dark stage,ZT 16.56.After the fish were starved for7 days,the expression of CAT1 gene showed no significant difference(p>0.05)at different time points and no circadian rhythm(p>0.3).The expression of CAT1 gene decreased first and then elevated during the light cycle,however,the expression of CAT1 gene increased first and then decreased during the dark period,in which the peak phase was in the dark stage,ZT 21.60.We conclude that the circadian rhythms of CAT1 gene in the muscle and liver of tilapia were different each other.