诺氟沙星对海月水母螅状体Hsp70基因、GTP结合蛋白基因和氧化应激蛋白基因表达的影响

摘要

诺氟沙星(norfloxacin,NFLX)广泛应用于水产养殖中的鱼类细菌性疾病治疗.为探讨诺氟沙星对海洋生物的毒性作用,选择海月水母螅状体为受试生物,考察了不同浓度诺氟沙星和不同暴露时间对GTP结合蛋白(GTP binding protein)、氧化应激蛋白(oxidative stress protein)和热休克70 kDa蛋白(heat shock 70 kDa protein,Hsp 70)表达量的影响.结果表明,NFLX对海月水母螅状体的48 h的半致死浓度(48 h-LC50)是415.1 mg·L-1,NFLX对海月水母螅状体的毒性属于低毒.随着NFLX浓度的升高和培养时间的延长,Hsp 70基因在第7天浓度300 mg·L-1时表达量受到显著性诱导(P＜0.05),较对照组升高9.1倍;GTP结合蛋白基因和氧化应激蛋白基因的表达量都呈现先急剧升高后降低的趋势.2个基因均在第1天受到显著性诱导(P＜0.05),分别在NFLX浓度100 mg·Lt和300 mg· L-1时表达量达到最大值,较对照组升高10.15倍和50.5倍.Hsp 70基因、GTP结合蛋白基因和氧化应激蛋白基因在实验期间都对NFLX表现出较好的响应.%Norfloxacin is widely used in the bacterial disease treatments in aquaculture.In order to study the norfloxacin toxicity to marine organisms,Aurelia autita polyps was exposed to NFLX to investigate its toxicity effects on the gene expression of GTP-binding protein,oxidative stress protein and heat shock 70 kDa protein.The results indicated LC50 of NFLX at 48 h was 415.1 mg·L-1,showing low toxicity to Aurelia aurita polyps.Hsp70 gene expression proliferated significantly with increasing time and concentration of NFLX,reaching the highest value at the seventh day at the NFLX concentration of 300 mg·L-1,which was up to 9.1-fold higher than the control group (P＜ 0.05).The gene expression of GTP binding protein and oxidative stress protein both sharply increased at the initial stages and gradually decreased.And they were significantly induced at the first day (P ＜ 0.05),reaching the highest value which were up to 10.15-fold and 50.5-fold higher than the control groups at the NFLX concentrations of 100 mg· L-1 and 300 mg·L-1,respectively.The genes of Hsp70,GTP binding protein and oxidative stress protein showed good responses to NFLX in the experimental period.