盐度和胁迫时间对九孔鲍α-淀粉酶基因表达量的联合效应分析

采用中心复合设计和响应曲面法研究了盐度和胁迫时间对九孔鲍(Haliotis diversicolor supertexta)?-淀粉酶基因表达量影响的联合效应,旨在为九孔鲍盐度驯化及海区推广提供指导。实验设定盐度范围为22~40,时间范围为0~72 h,建立了盐度、胁迫时间与?-淀粉酶基因表达量之间关系的定量模型,并通过分析明确了盐度和胁迫时间的最优组合。结果表明,盐度对九孔鲍?-淀粉酶基因表达量影响的一次效应不显著(P0.05),而二次效应极显著(P0.01),说明盐度与九孔鲍?-淀粉酶基因表达量之间为非线性关系。随盐度升高,淀粉酶基因表达量呈先上升后下降的变化趋势,当盐度为31时淀粉酶基因表达量最大,此时九孔鲍消化能力最强。胁迫时间对淀粉酶基因表达量影响的一次效应显著(P0.05),二次效应不显著(P0.05),表明胁迫时间与九孔鲍?-淀粉酶基因表达量之间呈线性关系,即随着胁迫时间的延长,淀粉酶基因从开始低水平表达逐渐升高并恢复至正常表达水平。盐度和胁迫时间之间不存在交互作用。对实验结果建立模型可知,?-淀粉酶基因表达回归模型达极显著水平(P0.05),且失拟项不显著(P0.05),表明实验拟合出的方程有效。回归方程的决定系数为80.05%,校正系数65.80%,预测系数50.18%,表明方程拟合度较好,模型选择较为恰当,可以为不同盐度和胁迫时间诱导下的淀粉酶基因表达量变化提供参考依据。

Synergistic effects of salinity and stress duration on alpha-amylase expression in Haliotis diversicolor supertexta

Haliotis diversicolor supertexta is mainly distributed in coastal waters off southern China and is a warmwater,economically important shellfish.H.diversicolor supertexta is characterized by rapid growth,a short breeding cycle,suitability for high density cultivation,and is nutritious,so there is high demand among consumers.Guangdong is often affected by typhoons,so more rain falls there than in other provinces.Sea salinity drops when rainfall increases,and the osmotic pressure in aquatic animals varies because of salinity changes,which can result in massive mortalities of abalone.H.diversicolor supertexta is a local species in Guangdong,making it particularly susceptible.Response surface methodology (RSM) is a collection of statistical and mathematical techniques to optimize a process.This methodology generates an empirical mathematical model that defines the effect of an independent variable on a response of interest to optimize the response.RSM has been applied in ecotoxicological studies of marine bivalve larvae and to investigate the effects of environmental variables on embryonic and larval development.RSM has not been used in any gastropod nutritional studies.In this study,the synergistic effects of salinity and stress duration on alpha-amylase gene expression were assessed using central composite design and RSM.The results show that the linear effects of salinity on alpha-amylase gene expression were not significant (P＞0.05),but the linear effect of stress duration was significant (P＜0.05),suggesting that expression of the amylase gene was affected by stress duration.In addition,the quadratic effects of salinity on amylase gene expression were significant (P＜0.05),but the quadratic effects of stress duration on amylase gene expression were not significant (P＞0.05).No synergism was detected between salinity and stress duration.The RSM model equation for the relationship between amylase gene expression and the two factors was established (R2=80.05％).The Adj.R2 value was 65.80％,and the Pre.R2 values was 50.18％,suggesting a good model fit for prediction.Maximal amylase gene expression was observed when salinity was 31,and stress duration was 36 h.H.diversicolor supertexta is affected by many factors,as it is cultured in a marine environment.Additional factors should be studied in the future.