急性拥挤胁迫对草鱼肌肉泛素-蛋白酶体系统活性的影响

泛素-蛋白酶体系统(theubiquitin-proteasomesystem,UPS)是细胞内调节蛋白质代谢的重要系统。在水温(17.0±0.5)℃下,将草鱼(Ctenopharyngodon idellus)暴露于100 kg/m2的养殖密度条件进行急性拥挤胁迫。在胁迫0 h、1 h、6 h、12 h、24 h和48 h以及取消胁迫后(养殖密度10 kg/m2)的6 h和168 h采集血清和背部肌肉样品,检测血清皮质醇水平、肌肉质构特性以及nrf2、hsp70和UPS相关基因表达,并定量测定了肌肉组织泛素化蛋白水平。结果表明,拥挤胁迫导致血清皮质醇含量显著上升,肌肉硬度和凝聚性显著性下降,以上各指标在取消胁迫后168 h恢复到对照水平,弹性、胶黏性、咀嚼性和回复性在恢复168h时反而高于对照组水平; hsp70和nrf2的表达量在胁迫48 h时显著高于对照组,后期恢复到对照水平;肌肉ub、psma2、psmc1、mafbx和chip的mRNA表达量在胁迫过程中显著性上升,胁迫后恢复168 h,还是表现出较高的表达量;处理组泛素化蛋白水平在胁迫6 h和12 h时显著升高,在恢复168 h时显著降低。研究表明,急性拥挤胁迫使草鱼产生明显的应激反应,对肌肉质构特性产生了显著性影响,同时提高了肌肉UPS的活性。经过168h的恢复,鱼体逐渐恢复到正常生理水平,但机体UPS活性仍呈现出被激活状态。急性拥挤胁迫对草鱼生理功能和肌肉质构特性的有害影响是可逆的,建议恢复时间大于168 h以帮助鱼体重新建立UPS的稳态。     

亚硝酸盐氮胁迫对鳙血液生化指标以及组织HSP70 mRNA表达水平的影响

为了探讨亚硝酸盐氮胁迫对鳙[初均重:(180.05±0.092)g]血液生化指标和组织热休克蛋白70基因表达水平的影响,实验选用170尾鳙,暴露于48.634 mg/L亚硝酸盐氮96 h后,进行96 h恢复实验。并在胁迫0、6、12、24、48、72和96 h以及恢复12、24、48、72和96 h时采集样品。结果显示,胁迫6 h后,血清皮质醇含量和谷丙转氨酶活性显著升高;胁迫12 h后,血清中葡萄糖含量显著升高;胁迫24 h后,血清总胆固醇含量开始显著降低;胁迫48 h后,血清总蛋白和甘油三酯含量开始显著降低,三碘甲状腺原氨酸含量和谷草转氨酶活性则显著升高;胁迫72 h后,血清低密度脂蛋白和高密度脂蛋白含量开始显著降低。恢复96 h后,鱼体血清生理指标大多都已恢复至胁迫前水平,而组织热休克蛋白70 mRNA表达水平的差异显示,头肾抗亚硝酸盐氮响应最快,其次为鳃和肠道,而脾脏热休克蛋白70 mRNA表达水平在恢复12 h时显著升高;恢复96 h后,除鳃组织外,肾脏、肠道和脾脏的热休克蛋白70 mRNA表达量均恢复至胁迫前水平。研究表明,亚硝酸盐氮对鳙的蛋白质代谢、脂质代谢和糖代谢均产生影响,并且诱导部分组织热休克蛋白70 mRNA的表达,而鳙对水体中高浓度的亚硝酸盐氮应激6 h即可产生快速应答,并启动防损伤自我保护机制,促进新陈代谢水平,保护机体免受应激损伤。     

邻苯二甲酸二丁酯对红鳍笛鲷幼鱼的胁迫效应

为了探讨邻苯二甲酸二丁酯(DBP)对红鳍笛鲷(Lutjanus erythropterus)幼鱼的胁迫效应,于DBP暴露后0、6、12、24、48和96 h时检测红鳍笛鲷鳃、肝和脑组织中超氧化物歧化酶(SOD)、丙二醛(MDA)和乙酰胆碱酯酶(AChE)活性。结果表明,DBP对红鳍笛鲷的24 h、48 h和96 h LC50分别为7.10 mg/L、6.98 mg/L和6.66 mg/L,安全质量浓度为2.04 mg/L。随着浓度增加,鳃组织中的SOD酶活性表现为先升高后下降,具有明显的时间效应;肝组织中的SOD酶活性在0.5 mg/L和2.0 mg/L浓度组交替表现为升高和降低,与对照组比较有显著性差异(P<0.05);而0.125 mg/L浓度组肝SOD没有明显变化。鳃组织中MDA含量在DBP暴露6 h后显著性增加(P<0.05),之后随时间延长而下降;DBP暴露6 h和12 h后,0.5 mg/L和2.0 mg/L浓度组肝组织中的MDA含量都显著升高(P<0.05),之后随时间延长MDA含量下降并趋于稳定。与对照组比较,DBP暴露48 h后,红鳍笛鲷脑组织中AChE酶活性显著升高(P<0.01),96 ...     

亚硝酸钠(NaNO2)对鲫鱼肝脏Na+/K+-ATPase和Mg2+-ATPase活性的影响

采用室内模拟方法,研究了亚硝酸钠对鲫鱼肝脏中Na /K -ATPase和Mg2 -ATPase活性的影响,共设4个亚硝酸钠浓度处理组(0.5mg/L、1.0mg/L、2.0mg/L和3.0mg/L),分别在染毒后24h、48h、72h和96h测定肝脏Na /K -ATPase和Mg2 -ATPase活性。结果表明,各NaNO2浓度处理组的Na /K -ATPase和Mg2 -ATPase活性均表现出相似的变化关系:在染毒后24h,所有浓度组活性升高,在暴露后48h和72h时活性下降。暴露后96h,各处理组的Na /K -ATPase和Mg2 -ATPase活性又开始增加,并高于对照组酶活性,但Na /K -ATPase与对照组差异不显著,且随着NaNO2浓度的增大,酶活性逐渐降低,而Mg2 -ATPase各浓度处理组在暴露后96h,活性增加并显著高于对照组,二者均呈现出浓度-效应的负相关。以上结果表明Na /K -ATPase和Mg2 -ATPase在离子调节中共同作用,以对亚硝酸钠应激作出反应,有可能成为水体中亚硝酸盐氮胁迫的一个合适的生物指示剂。     

不同质量浓度铅对草鱼鱼种抗氧化性能的影响

将草鱼暴露于不同水平(0、72、144、288 mg/L)的硝酸铅水溶液中,分别于12、24、48、96 h测定草鱼肝、鳃组织中谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量.试验结果表明,当鱼经不同质量浓度Pb2+处理24 h后,其肝脏的GSH-Px活性表现为诱导效应;而鳃在低质量浓度(72 mg/L)Pb2+处理也表现诱导效应,但高质量浓度Pb2+(144、288 mg/L)处理24 h后,其GSH-Px活性表现为抑制效应.与肝GSH-Px相比,草鱼肝SOD经Pb2+处理后其活性抑制更加明显,表明肝SOD对Pb2+的毒性反应比肝GSH-Px敏感.同时,草鱼经不同质量浓度Pb2+处理12 h后,肝与鳃的MDA含量均比对照组明显增加.上述研究结果表明,水体铅可能通过诱导草鱼肝脏与鳃发生氧化损伤而发挥毒性作用,并进一步损伤机体结构及其生理功能.     

亚硝酸盐对凡纳滨对虾血细胞毒性及p53基因表达的影响

随着水产动物集约化养殖的迅猛发展,水质污染问题日益加剧,环境中亚硝酸盐的含量不断上升,成为水产养殖中诱发爆发性疾病的重要环境因子。为探讨亚硝酸盐对凡纳滨对虾（Litopenaeus vannamei）血细胞的毒性以及 p53 mRNA 的影响,通过预试验以及前期资料获取亚硝酸盐对凡纳滨对虾的毒性效应,选取0 mg／L 对照组和20 mg／L 浓度组,用流式细胞术检测血细胞活性氧（ROS）、一氧化氮（NO）含量和非特异性酯酶活性,运用荧光定量 PCR 技术检测 p53基因表达量变化。结果显示,在亚硝酸盐应激12 h 后,对虾血细胞的 NO 含量与对照组相比有显著升高（P ＜0．05）,在应激24、48、72 h 后有极显著的升高（P ＜0．01）;ROS 含量在应激12、48、72 h 时有极显著升高（P ＜0．01）,在应激24 h 时与对照组相比有显著的升高（P ＜0．05）。非特异性酯酶活性在应激24、48、72 h 显著下降（P ＜0．05）,p53的表达水平在应激48 h 和72 h 后显著升高（P ＜0．05）。研究表明,亚硝酸盐应激诱导对虾血细胞产生了过量的 NO 和 ROS,造成氧化胁迫作用,诱导凋亡相关基因的表达,最终导致细胞凋亡。     

亚硝酸钠对鲫鱼肝脏过氧化氢酶活性的影响

采用室内模拟方法,研究了不同亚硝酸钠浓度(0.5mg/L、1.0mg/L、2.0mg/L和3.0mg/L)处理不同时间后对鲫鱼肝脏过氧化氢酶(CAT)活性的影响。实验结果表明:在处理后24h,各浓度处理组的CAT活性增加;当处理时间延长时,2.0mg/L和3.0mg/L处理组CAT活性受到抑制,抑制程度与其剂量高低和暴露时间的长短呈正相关,表现出显著的浓度-效应和时间-效应关系;而0.5mg/L和1.0mg/L处理组CAT活性在暴露后48h显著升高,在96h时下降至稍低于对照组。结果表明,CAT活性对亚硝酸钠胁迫较为敏感,提示有可能成为水体中亚硝酸盐氮浓度升高的一个合适的生物指示剂。     

氨氮胁迫对青鱼幼鱼鳃丝Na+/K+-ATP酶、组织结构及血清部分生理生化指标的影响

氨氮是诱发鱼病的主要环境因子,以初始体质量(7.00 0.14)g的青鱼幼鱼为研究对象,研究氨氮胁迫对其鳃丝Na+/K+-ATP酶、组织结构及血清部分生理生化指标的影响。实验设置低(对照组0 mg/L)、中(10 mg/L)和高(20 mg/L)3个氨氮浓度处理组,将暂养在自然淡水(对照)中的青鱼幼鱼分别放入各实验梯度中,进行0、6、12、24、48和96 h氨氮胁迫。结果表明:与对照组相比,中、高氨氮组鳃丝Na+/K+-ATP酶活性分别在12 h和6 h降至最低,然后升高,48 h达最大值,96 h后与对照组水平相当。鳃组织光镜观察表明,中氨氮组鳃小片基部泌氯细胞数量12 h有所增加,24 h呼吸上皮细胞出现部分脱落,96 h泌氯细胞出现空泡化,部分鳃小片充血;而高氨氮组鳃小片基部泌氯细胞数量6 h呈增加趋势,12 h呼吸上皮细胞部分脱落,24 h大面积脱落,96 h鳃小片基部严重充血。血清皮质醇和血糖含量在胁迫12 h均升高至最大,含量与氨氮浓度呈正相关,48 h恢复至对照组水平。氨氮胁迫下,血清总超氧化物歧化酶(SOD)活力呈先升高后降低的趋势,6 h时显著高于对照组(P<0.05),中氨氮组12 h后与对照组差异不显著,而高氨氮组96 h时显著低于对照组(P<0.05)。过氧化氢酶(CAT)活力12 h内均呈先降低后升高趋势,48 h均恢复至对照组水平。氨氮胁迫前期,血清总抗氧化力和谷胱甘肽均呈下降趋势,丙二醛和谷丙转氨酶活力呈升高趋势。谷胱甘肽和谷丙转氨酶活力在96 h恢复至对照组水平,而丙二醛96 h仍显著高于对照组,高氨氮组总抗氧化力显著低于对照组(P<0.05)。由此可见,氨氮胁迫初期,鱼体抗氧化系统受到严重干扰。随着胁迫时间延长,鱼体进行适应性生理调节,但机体抗氧化能力下降,鳃组织已受到损伤。     

急性氨氮暴露对大弹涂鱼炎性反应相关基因表达的影响

为研究急性氨氮胁迫对大弹涂鱼炎性反应相关基因表达的影响,实验挑选初始体质量为(15.14±0.05) g的健康大弹涂鱼幼鱼180尾,进行96 h的急性氨氮胁迫实验。结果显示,大弹涂鱼96 h氨氮半致死浓度为8.99 mg/L总氨氮(0.11 mg/L非离子氨,T-AN);氨氮胁迫后TNF基因的mRNA表达量分别于12和96 h时显著上调,96 h时表达量达到0 h时的2倍;IL-1基因的mRNA表达量12 h时显著上调,为0 h时表达量的6倍;氨氮胁迫后IL-6基因的mRNA表达量分别于12和96 h时显著上调,表达量达到0 h时的1.5倍;氨氮胁迫后IL-8基因的mRNA表达量在24 h时出现显著下调。研究表明,大弹涂鱼96 h氨氮半致死浓度为8.99 mg/L总氨氮;半致死浓度的氨氮胁迫48 h后,TNF、IL-1、IL-6和IL-8基因的mRNA表达量持续升高,推测过度炎性应激可能是导致鱼类氨中毒死亡的原因之一。     

低浓度Cd2+胁迫对青鱼组织SOD活性和MT诱导的影响

采用静水试验方法,研究了Cd2+对青鱼的急性毒性效应以及Cd2+安全浓度胁迫对青鱼鳃丝、肌肉和肝脏的超氧化物歧化酶(SOD)和金属硫蛋白(MT)的影响。结果表明:Cd2+对青鱼的96 h LC50为1.434 mg/L,Cd2+对青鱼的生态毒性为高毒。在0.143 mg/L(安全浓度)Cd2+胁迫下,各组织中SOD活性和MT含量在6 h、12 h内显著上升,呈现出一定时间-效应关系,以暴露6 h时最为显著(P0.05);暴露12 h后,MT的含量基本上趋于平衡,而SOD活性却是快速下降,表明了12 h后该浓度Cd2+污染胁迫对SOD活性的抑制作用。整个试验期间,对照组青鱼各组织中的SOD活性和MT含量大小顺序皆为肝脏鳃丝肌肉,同种组织内相对比较稳定;肌肉中的SOD活性要显著低于鳃丝和肝脏,而肝脏中的MT含量要显著高于肌肉和鳃丝。     

Acute Toxicity and Sublethal Effects of Nitrite on Selected Hematological Parameters and Tissues in Dark-banded Rockfish, Sebastes inermis

Acute toxicity and sublethal effects of nitrite in dark‐banded rockfish, Sebastes inermis (83.3 ± 7.2 g), were studied under static conditions for a period of 96 h. The acute toxicity of nitrite evaluated for the 96‐h lethal concentration (LC₅₀) was 700 mg/L. The sublethal effects on selected hematological parameters of S. inermis, such as total erythrocyte count (TEC), hemoglobin, plasma glucose, and serum protein content, were measured after 0, 6, 12, 24, 48, 72, and 96 h of exposure to 0, 50, 100, 200, 400, and 700 mg/L of nitrite. Sublethal nitrite caused progressive reduction in the TEC, hemoglobin, and serum protein content in fish depending on the nitrite concentration and exposure period. The 96‐h exposure resulted in a 14–42% reduction in TEC and 25–33% reduction in hemoglobin content for 100–700 mg/L of nitrite compared to the control. A dose‐related reduction in plasma glucose (25.7–34.2%) was observed for concentrations of 200–700 mg/L of nitrite during 48 h of exposure, followed by an increase through 96 h. A significant reduction in serum protein (7.3–12.6%) was observed for 200–700 mg/L of nitrite after 96 h of exposure. Abnormal histological changes in skin, gill, liver, and kidney tissue were observed in fish exposed to 700 mg/L of nitrite after 96 h of exposure compared to the control. Although no mortality of S. inermis occurred at 500 mg/L of nitrite, all hematological parameters adversely responded to a nitrite dose of 200 mg/L for 96 h. These results showed that although acute toxicity concentration of nitrite in S. inermis is higher than 700 mg/L, sublethal concentrations of nitrite also negatively affect hematological parameters.     

盐度胁迫对大鳞鲃抗氧化酶和血清皮质醇的影响

为阐明盐度胁迫对大鳞鲃(Luciobarbus capito)肝、肾和鳃组织抗氧化系统及血清皮质醇的影响,本研究设置4个NaCl盐度组(3、6、9和12 g/L)和1个淡水对照组,检测分析了不同盐度胁迫下曝露3、6、12、24、48、96 h和7 d大鳞鲃肝、肾和鳃组织中酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、谷胱甘肽过氧化物酶(GSH-Px)的活性和丙二醛(MDA)含量的变化,以及血清中皮质醇浓度的变化。结果显示,在相同盐度胁迫下,大鳞鲃的肝、肾和鳃组织中ACP、AKP、GSH-Px抗氧化酶的活力、MDA含量以及血清皮质醇含量随胁迫时间的延长均呈先上升后下降、随后趋于稳定的变化趋势,在胁迫开始24 h内各指标达到峰值,并在48 h开始逐渐趋于平稳;胁迫初期,相同曝露时间,大鳞鲃的肝、肾和鳃组织中3种抗氧化酶活力、MDA含量及血清皮质醇含量均与盐度呈显著正相关性。大鳞鲃在盐度胁迫过程中,ACP、AKP活力和MDA含量在肾组织的范围分别为1.42~2.15 U/g prot、1.01~1.87金氏单位/g prot和13.05~57.27 nmol/mg prot;肝组织中分别为1.27~1.96 U/g prot、0.31~0.86金氏单位/g prot和17.02~55.98 nmol/mg prot;鳃组织则为0.98~1.96 U/g prot、0.13~0.84金氏单位/g prot和8.33~53.93 nmol/mg prot,肾组织中ACP、AKP活力和MDA含量均高于肝、鳃组织;而GSH-Px的活力在肝、肾和鳃组织的范围分别为44.41~114.77、16.52~67.59和9.07~48.00活力单位,肝组织中GSH-Px活力显著高于肾和鳃组织。此外,血清皮质醇在盐度胁迫过程中的含量变化范围为197.00~355.50 ng/L。综上所述,在12 g/L的高盐胁迫下大鳞鲃通过自身调节,各项指标仍可恢复正常,表明其对盐度环境有较强的适应能力。     

Physiological and Biochemical Responses of Nile Tilapia (Oreochromis niloticus) Exposed to Aqueous Extracts of Neem (Azadirachta indica)

In this study, the physiological and biochemical response of Nile tilapia (Oreochromis niloticus) after 96 and 24 h exposure to aqueous extracts of neem (Azadirachta indica) in extract concentrations ranging from 0 to 32,000 mg/l was evaluated. After 96 h and 24 h exposure, the LC₅₀ of neem extract was estimated at 3,200 and 6,800 mg/l, respectively. Plasma cortisol increased beyond pre-treatment levels at neem extract concentrations above 2,000 mg/l over 96 h and above 4,000 mg/l over 24 h. Blood glucose increased at neem extract concentrations above 1,000 and 5,000 mg/l at 24 and 96 h, respectively. Neem extract concentration had little effect on serum sodium and plasma chloride. Hematocrit was higher than the control at neem extract concentrations above 1,000 mg/l in the 96 h exposure and above 2,000 mg/l in the 24 h exposure. Plasma ammonia increased significantly at neem extract concentrations above 2,000 mg/l for both the 96 h and 24 h tests. Immediately after beginning treatment, cortisol levels increased significantly at neem extract concentrations above 2,000 mg/l in the 96 h test and 4,000 mg/l in the 24 h toxicity test. Exposure to neem extract interfered with the antioxidant defense system of the fish by reducing liver catalase activity. Even though extracts of neem are less toxic at low concentration, concentrations exceeding 3,200 mg/l influence physiological and biochemical disturbances in fish.     

LAS与Cu2+单一及复合污染对泥鳅肝脏SOD、CAT活性的影响

采用暴露试验法研究了十二烷基苯磺酸钠（LAS）与Cu^2＋单一及复合污染对泥鳅肝脏超氧化物歧化酶（SOD）、过氧化氢酶（CAT）活性的影响。试验结果表明，单一LAS处理96h后，SOD活性变化不显著，CAT在LAS为20．0mg／L时被显著诱导（P〈0．05）；单一的Cu^2＋处理96h后，泥鳅肝脏SOD、CAT活性受到显著影响（P〈0．05），随着质量浓度的增加，表现为先诱导后抑制；LAS、Cu^2＋复合处理条件下，LAS为10．0mg／L时，CAT、SOD活性分别在Cu^2＋质量浓度为0．05、0．10mg／L时达到最低值，LAS为20．0mg／L时，CAT、SOD活性有所回升，但其活性仍低于对照组，且差异均达到显著水平（P〈0．01）。通过比较，发现泥鳅肝脏CAT活性变化更能反映出污染物对泥鳅的毒性作用。     

Alterations in serum electrolytes, antioxidative enzymes and haematological parameters of Labeo rohita on short-term exposure to sublethal dose of nitrite

An experiment was conducted to study the effects of short-term exposure to sublethal levels of nitrite on electrolyte regulation, antioxidative enzymes and haematological parameters in Labeo rohita juveniles. The fishes were exposed to graded levels of nitrite (0-15?mg?l(-1)) for different duration (0, 12, 24, 48 and 96?h). The 96-h LC(50) value for L. rohita (avg. wt, 66.5?±?0.5?g) was found to be 11.28?mg?l(-1). Activities of antioxidative enzymes (catalase and superoxide dismutase), acetylcholine esterase (AChE) and methaemoglobin reductase, serum electrolytes (sodium, potassium and chloride), haematological parameters and blood glucose level significantly varied (P?相似文献   

Joint Action of Ammonia and Nitrite on Tiger Prawn Penaeus monodon Postlarvae

Tiger prawn Penaeus monodon postlarvae (PL6) were exposed to a mixture of ammonia and nitrite by the static renewal method. When the toxicity ratio of the ammonia-nitrite mixture was 1:1, the 48 h, 72 h and 96 h LC50 values were 2.20, 1.43 and 0.84 toxicity units which were equivalent to 12.66 mg/L ammonia-N (0.60 mg/L NH₃-N) plus 14.91 mg/L nitrite-N, 8.23 mg/L ammonia-N (0.39 mg/L NH₃-N) plus 9.69 mg/L nitrite-N, and 4.83 mg/L ammonia-N (0.23 mg/ L NH₃-N) plus 5.69 mg/L nitrite-N. When the toxicity ratio of the ammonia-nitrite mixture was 51, the 48 h, 72 h and 96 h LC50 values were 2.50, 1.56 and 0.85 toxicity units which were equivalent to 23.98 mg/L ammonia-N (1.13 mg/L NH₃-N) plus 5.65 mg/L nitrite-N; 14.96 mg/L ammonia-N (0.71 mg/L NH₃-N) plus 3.52 mg/L nitrite-N, and 8.15 mg/L ammonia-N (0.39 mg/ L NH, N) plus 1.92 mg/L nitrite-N. A mixture of ammonia and nitrite exerted greater toxicity than high concentrations of either ammonia or nitrite alone. The combined effect of ammonia and nitrite on P. monodon postlarvae was antagonistic for 48 and 72 hours exposure, but synergistic after 96 hours exposure.     

Acute effects of ammonia exposure on the plasma and haematological parameters and histological structure of the juvenile blunt snout bream,Megalobrama amblycephala,and post‐exposure recovery

In this study, we investigated the toxic effects of ammonia‐N on the plasma and haematological parameters and histological structure of blunt snout bream (Megalobrama amblycephala) juveniles. The fish (initial weight, 14.79 ± 0.01 g) were randomly sorted into six tanks (200 L), and each tank was stocked with 40 fish for culture. The juveniles were exposed to two ammonia‐N levels—0 mg/L (control group) and 25 mg/L (experimental group)—and sampled at 0, 6, 12, 24, 48 and 72 hr, and then they underwent 96 hr of post‐exposure recovery. The results showed that ammonia‐N had significant effects on the plasma and haematological parameters. The treatment group showed increased cortisol, plasma ammonia and haematocrit levels and white blood cell count with increasing exposure time, up to 24 hr, and then the levels and count decreased. A significantly higher plasma glucose level was observed in the treatment group at 12 hr. After 96 hr of post‐exposure recovery, all parameter levels decreased to the control levels. The fish displayed histopathological alterations in the gills, liver and kidney. The results indicate that the severity of the lesions clearly differed among the organs, with the liver showing the most extensive damage, followed by the gills and kidney. Adverse effects to physiological indicators and histological structure increased with increasing exposure time before 24 hr. The fish showed self‐regulation; however, the histological structure could not recover fully, the gill tissue showed irreversible changes and the kidney tissue exhibited the worst recovery ability.     

亚硝态氮对中华鳑鲏的急性毒性及短期影响

静水试验条件下研究了亚硝态氮对体质量(0.636±0.09) g的中华鳑鲏急性毒性及短期胁迫下对其体内两种酶活性的影响。在水温25℃、溶解氧6.3 mg/L、pH 7.4时,测定亚硝态氮对中华鳑鲏的24 h半致死质量浓度,并设置高、中、低3个亚硝态氮质量浓度组[1.28、0.64、0.43 mg/L(1/10×24 h半致死质量浓度、1/20×24 h半致死质量浓度、1/30×24 h半致死质量浓度)],于0、24、48、72 h采集血样,测定血清中过氧化氢酶和碱性磷酸酶的活性。试验结果表明,亚硝态氮对中华鳑鲏的24 h半致死质量浓度为12.76 mg/L。在亚硝态氮胁迫作用下,中华鳑鲏血清中过氧化氢酶活性先显著上升,48 h后开始下降;碱性磷酸酶活性变化则是先显著下降,在48 h恢复,然后再下降。碱性磷酸酶活性在24 h和72 h均受到明显抑制。亚硝态氮质量浓度和暴露时间两者之间存在显著交互作用,碱性磷酸酶可以作为亚硝态氮毒性检测的生物标记物。     

盐酸小檗碱对草鱼补体系统及补体c3作用的研究

为了探究盐酸小檗碱(berberine hydrochloride)对草鱼(Ctenopharyngodon idellus)补体c3的作用机理,用含0、0.06%、0.12%、0.24%盐酸小檗碱饲料投喂草鱼,在第7 d、14 d检测血清中补体c3含量,在第14 d检测肝脏中补体c3 mRNA表达量及急性感染嗜水气单胞菌(Aeromonas hydrophila)后存活情况。并进一步对盐酸小檗碱体内药代动力学和补体消耗试验进行了研究。结果显示;摄食盐酸小檗碱的草鱼血清中补体c3含量和肝脏补体c3 mRNA表达量均显著性增加(P0.05/P0.05),草鱼的存活率与对照组相比也有显著性提高(P0.01)。补体消耗试验结果显示,当盐酸小檗碱在血清中浓度小于5 mg/L时与对照组相比补体消耗不显著,当盐酸小檗碱浓度大于5 mg/L时,补体消耗达到显著性差异(P0.05),表明此时盐酸小檗碱与补体c3直接结合,激活补体。药代动力学实验发现,灌服盐酸小檗碱后,出现双峰现象,两峰值分别是0.243 mg/L和0.117 mg/L,此浓度远远低于与补体c3直接结合量最低量(5 mg/L)。结果表明,盐酸小檗碱对草鱼补体c3的作用机理可能是通过上调补体c3mRNA的表达增加补体c3数量,而非通过直接结合补体c3来改变其活性。