pH胁迫对中国明对虾抗氧化系统酶活力及基因表达的影响

研究了pH胁迫对中国明对虾(Fenneropenaeus chinensis)抗氧化系统的影响,将中国明对虾暴露于pH7.0、9.0的水体中148 h,于胁迫后0、3、12、24、48、72、96、120、148 h测定鳃、肝胰腺、肌肉和血淋巴总抗氧化活力(T-AOC)、抗超氧阴离子活力、过氧化氢酶(CAT)活力和CA...     

氨氮胁迫对三疣梭子蟹酚氧化酶原系统和免疫指标的影响

以三疣梭子蟹(Portunus trituberculatus)为研究对象,研究氨氮胁迫对其酚氧化酶原系统和免疫指标的影响.实验分0mg/L、1 mg,L、5mg,L、20mg,L氨氮处理组,分别于0h、6h、12 h、24 h、48 h取样并进行相关指标测定.结果表明:氨氮胁迫对三疣梭子蟹血淋巴多巴胺含量、血细胞数量、血细胞酚氧化酶原(proPO)活力和mRNA表达以及抗菌、溶菌活力的影响显著(P<0.05).各处理组血淋巴多巴胺含量于6 h达到最大值,12 h后恢复至对照组水平;各处理组血细胞数量均呈明显下降趋势,除20mg/L氨氮处理组半颗粒细胞、总细胞数量表现为逐渐下降趋势外,其他处理组3类血细胞和总细胞数量分别于12h或24h时降至最低值,然后保持稳定.各处理组上述指标分别呈明显下降、升高、下降和峰值变化趋势,其中1mg/L处理组血细胞proPO活力在12 h后恢复至对照组水平,而mRNA表达与对照组差异不显著,其他处理组血细胞proPO活力和mRNA表达分别于12h、6h后保持稳定;各处理组抗菌活力于6h或12h达到最小值,然后恢复至对照组水平,而溶菌活力在24 h后趋于稳定,且1 mg/L处理组与对照组无明显差异.各处理组血细胞数量、proPO活力、溶菌活力在稳定后均与氨氮浓度呈明显的负相关性,而血细胞proPO mRNA表达呈显著正相关性.由此可见,三疣梭子蟹在氨氮胁迫下血细胞数量、proPO活力和mRNA表达以及免疫指标表现出明显的时间剂量效应性,具有显著的免疫毒性效应.本研究旨在为三疣梭子蟹养殖水环境调控和病害防治提供基础依据.     

福瑞鲤对氨氮胁迫的生理响应

以福瑞鲤(Cyprinus carpio)为材料,研究不同浓度氨氮(0、10、20和30 mg/L)处理对幼鱼鳃组织中抗氧化系统和Na~+/K~+-ATP酶活力的影响。结果显示,氨氮胁迫6 h诱导H_2O_2含量、总抗氧化能力(T-AOC)和超氧化物歧化酶(SOD)活性迅速显著升高,并在胁迫24 h时达到最高水平。胁迫96 h后,各处理组H2O2含量、SOD活性和总抗氧化能力均低于对照组水平,MDA含量显著增加。氨氮胁迫后,Na~+/K~+-ATP酶基因转录水平和蛋白活性呈先降低后升高又降低的变化趋势,参与胁迫过程中渗透压的调控。研究结果表明,低浓度氨氮胁迫后,福瑞鲤鳃组织通过调节细胞抗氧化能力,提高Na~+/K~+-ATP酶活性,有效改善鱼体的抗氨氮胁迫能力,但是高浓度氨氮胁迫对鳃组织造成氧化损伤。     

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。     

氨氮胁迫下凡纳滨对虾对副溶血弧菌的易感性

为探讨养殖水体中总氨氮胁迫对凡纳滨对虾(Litopenaeus vannamei)"急性肝胰腺坏死综合征(Acute Hepatopancreatic Necrosis Syndrome,AHPNS)"发生的影响,设置了1个对照组和4个不同质量浓度氨氮实验组:2.5、5.0、7.5、10.0 mg/L实验组,胁迫20 d后腹肌注射副溶血弧菌(Vibrio parahaemolyticus)进行感染。凡纳滨对虾感染后6–24 h,除对照组外,各实验组均出现死亡高峰。24 h后,5.0、7.5和10 mg/L实验组对虾累积死亡率均高于2.5 mg/L组,且在同一取样时间各实验组对虾累积死亡率随着氨氮浓度的升高而升高,48 h后各实验组对虾不再死亡,其累计死亡率分别为0、8%、12%、20%和36%。PO活性呈现先升高再降低的趋势,对照组、2.5和5.0 mg/L实验组PO活性差异性不显著(P0.05),7.5和10 mg/L实验组除12 h外均显著低于对照组(P0.05)。SOD活性呈现先升高后下降的趋势,7.5和10 mg/L实验组SOD活性在感染后除24 h外均显著高于对照组(P0.05),而2.5 mg/L实验组与对照组差异性不显著(P0.05)。对照组和2.5 mg/L实验组对虾LSZ活性在各取样时间点差异性不显著(P0.05),7.5和10 mg/L实验组对虾LSZ活性在3 h、6 h、24 h、48 h时间点显著低于对照组(P0.05)。感染6 h后各实验组对虾肝胰腺中Lv LT m RNA表达量开始上升,24 h后开始下调,至72 h恢复至原水平。实验结果表明,氨氮胁迫能降低凡纳滨对虾的非特异性免疫酶活性,影响对虾肝胰腺中Lv LT m RNA对病原刺激的应答反应,增加对副溶血弧菌的易感性,为预防凡纳滨对虾AHPNS的暴发,养殖水体中总氨氮浓度应控制在1.96 mg/L以下。     

氨氮胁迫对凡纳滨对虾肠道免疫相关指标的影响

为研究急性氨氮胁迫对凡纳滨对虾(Litopenaeus vannamei)肠道免疫功能的影响,将对虾暴露于氨氮浓度为20 mg·L^-1的海水中72 h,测定了不同时间点肠道中抗病原感染指标如酸性磷酸酶(ACP)、碱性磷酸酶(ALP)、溶菌酶(Lys)、酚氧化酶原(proPO)以及抗氧化功能指标如总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)、热休克蛋白70(HSP70)、热休克蛋白90(HSP90)等变化。结果显示,与对照组相比,氨氮胁迫后:1)ACP和ALP活性均于6 h显著升高(P<0.05),随后于48～72 h显著低于对照组(P<0.05);Lys活性于24 h显著升高至最大值(P<0.05),随后于72 h显著低于对照组(P<0.05)。2)T-AOC和SOD活性均于6 h和12 h显著高于对照组(P<0.05),随后于48 h和72 h显著降低(P<0.05)。3)HSP70基因表达水平于24 h显著升高至最大值,随后虽有降低,但仍显著高于对照组(P<0.05);HSP90和proPO基因表达水平均于12...     

pH、氨氮胁迫对中国对虾HSP90基因表达的影响

研究了pH、氨氮胁迫对中国对虾Fenneropenaeus chinensis血细胞、肝胰腺、鳃和肌肉组织HSP90基因时空表达的影响.分别将中国对虾暴露于pH7.0、9.0的水体中148h和不同氨氮浓度的水体中96h,结果表明,pH（7.0,9.0）胁迫条件下中国对虾鳃、肌肉和血细胞HSP90基因表达均上调,肝胰腺HSP90基因表达对两种pH胁迫差异明显：pH7.0胁迫条件下,HSP90基因表达3h达峰值后明显降低;pH 9.0胁迫时,HSP90基因表达水平逐渐升高,整个胁迫过程中均显著高于对照组（P＜0.05）,说明中国对虾肝胰腺组织是高pH胁迫的响应器官.6mg/L氨氮浓度组鳃和肌肉组织HSP90基因表达水平24h达最高值,分别为对照组的5.46和1.55倍;各胁迫组肝胰腺和血细胞HSP90基因表达水平分别于6h和48h达到最高值,为对照组的1.33～2.08倍和2.20～5.45倍.肝胰腺组织对氨氮胁迫表现敏感,短时间内（6h）通过上调HSP90基因表达水平保护细胞;鳃组织HSP90基因表达波动范围最大,说明鳃组织需要更高表达量的HSP90保护细胞.当氨氮浓度持续48～96h维持在2～6mg/L,各组织HSP90基因表达水平显著降低.     

氨氮胁迫对锦绣龙虾代谢酶和抗氧化酶活力的影响

为了研究急性氨氮胁迫对锦绣龙虾(Panulirus ornatus)抗氧化系统及氨氮代谢机制的影响,通过设置对照[(0.24±0.07)mg/L]、低浓度[(1.04±0.08)mg/L]、中浓度[(9.75±0.21)mg/L]和高浓度[(19.87±0.46)mg/L]氨氮胁迫方法对锦绣龙虾进行48 h急性实验,测...     

硫化物胁迫对凡纳滨对虾血细胞的毒性影响

硫化物是水产养殖过程中常见的水体污染物之一。为探讨水体硫化物胁迫对虾类血细胞的毒性影响,以不同浓度(0.5 mg/L,2.0 mg/L)的硫化物对凡纳滨对虾(Litopenaeus vannamei)进行胁迫,于胁迫后6、12、24和48 h取血淋巴,应用流式细胞术测定血细胞的总数(THC)、活性氧(ROS)含量、一氧化氮(NO)含量以及凋亡率。结果显示,经0.5 mg/L硫化物胁迫48 h后,对虾THC显著下降至11.78×10~6个/mL,为对照组的72.7%(P0.05),ROS含量为对照组的225.2%(P0.05),血细胞凋亡率显著上升至7.42%(P0.05);经2.0 mg/L硫化物胁迫6 h开始,对虾THC呈现显著的下降(P0.05),血细胞ROS含量和凋亡率显著提高(P0.05);表明硫化物胁迫刺激对虾血细胞产生大量ROS,诱导血细胞凋亡,从而导致THC下降,这一过程可能是硫化物导致虾类细胞免疫下降的重要机制;随着硫化物浓度的升高,其细胞毒性作用明显提高。血细胞NO含量在2.0 mg/L硫化物胁迫12和48 h时显著升高(P0.05),推测NO可能在硫化物胁迫防御调控中起着信号因子的作用。     

氨氮短期胁迫与恢复对克氏原螯虾的影响

为探究氨氮胁迫与恢复对克氏原螯虾抗氧化和免疫酶活性及组织结构的影响,将体质量(6.33±0.73)g的克氏原螯虾暴露于0、20、40、60、80 mg/L 5个氨氮质量浓度下,比较胁迫48 h时及恢复48 h后,各组肝胰腺、鳃和血清的抗氧化和免疫酶活性以及各组肝胰腺和肌肉组织结构的变化。试验结果显示：氨氮对克氏原螯虾幼虾24、48、72、96 h的半致死质量浓度分别为359.37、238.09、196.34、162.00 mg/L,安全质量浓度为16.20 mg/L。胁迫48 h后,除20 mg/L试验组外,其余试验组肝胰腺的总超氧化物歧化酶活性较对照组显著增强,80 mg/L组鳃的总抗氧化能力显著降低、过氧化氢酶活性显著增强,80 mg/L组血清的总超氧化物歧化酶活性显著增强;恢复48 h后,60 mg/L组肝胰腺和鳃的丙二醛含量较对照组显著上升,80 mg/L组鳃的过氧化氢酶活性较对照组显著增强,60 mg/L组血清的总抗氧化能力较对照组显著上升,其他试验组酶活性均恢复至对照组水平。氨氮胁迫48 h,随着氨氮质量浓度的升高,肝胰腺管腔逐渐变形、转运泡增大,鳃的呼吸上皮细胞开始脱落、...     

Hemolymph Oxyhemocyanin and Protein Levels and Acid-Base Balance in the Tiger Shrimp Penaeus monodon Exposed to Copper Sulfate

Abstract.— Subadult tiger shrimp Penaeus monodon (30.15 ± 2.19 g) were exposed individually in sea water of 25%o to 0 (control), 1.11, 4.76, 10.06 and 19.09 mg/L copper for 24 h. Hemolymph pH, PO₂ (partial oxygen pressure), PCO₂ (partial carbon dioxide pressure), HCO₃, oxyhemocyanin and protein levels were determined. Hemolymph PO₂ increased, whereas hemolymph pH, PCO₂, HC0₃-, oxyhemocyanin. protein and the ratio of oxyhemocyanidprotein levels decreased with increasing concentrations of ambient copper in the range of 1.11 to 19.09 ma/L. It is concluded that P. monodon following 24-h exposure to ambient copper as low as 4.76 mg/L shows a reduction of oxyhemocyanin, protein, and the ratio of oxyhemocyanin to protein, and develops metabolic acidosis in the hemolymph.     

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。     

Haemolymph nitrogenous constituents and nitrogen efflux rates of juvenile shrimp, Penaeus paulensis (Perez-Farfante), exposed to ambient ammonia-N

The effects of increased levels of ambient ammonia-N (7, 20 and 50 mg L^–1) on some blood nitrogenous constituents, and on ammonia-N and urea-N efflux rates of Penaeus paulensis are reported. Haemolymph urea, protein and haemocyanin levels, and the haemocyanin:protein ratio were not significantly altered in any of the situations tested. Sudden exposure to 20 mg L^–1 caused a transient increase in haemolymph ammonia-N levels, and induced pH and uric acid-N levels to increase after 24 h of exposure. A similar transient increase in haemolymph ammonia-N levels occurred during recovery, and the original pH and uric acid-N levels were restored within 30 min. The haemolymph ammonia-N and uric acid-N levels of shrimp held in 50 mg L^–1 for 24 h were higher than those held in low ammonia-N sea water at all times (control). Increased ammonia-N effluxes were found to occur upon recovery, but urea-N effluxes were not different from those of control shrimp. The amounts of ammonia-N which accumulated in the haemolymph of shrimp at high ambient ammonia-N levels were considerably lower than those excreted during the recovery period. Such findings indicate that some of the accumulating haemolymph ammonia-N was transformed into other compounds or stored elsewhere. Possible mechanisms involved are discussed.     

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.     

Detoxification Pathways in Response to Environmental Ammonia Exposure of the Cuttlefish,Sepia pharaonis: Glutamine and Urea Formation

To investigate the ammonia detoxification pathways of the cuttlefish, Sepia pharaonis, the effects of environmental ammonia nitrogen exposure (control, 1, 3, and 6 mg/L) on nitrogen metabolism were quantified in the hemolymph, liver, and gills. The levels of glutamine synthetase, glutamate dehydrogenase, and arginase activities and ammonia, glutamine, and urea concentrations in the hemolymph, liver, and gills significantly increased upon exposure to 3 and 6 mg/L ammonia nitrogen and exhibited a dose‐dependent relationship with the ammonia exposure concentration. These results suggest two main pathways of metabolic ammonia detoxification in S. pharaonis exposed to ammonia in this study: (1) conversion of ammonia to urea, which is stored temporarily or excreted, via the ornithine‐urea cycle and (2) conversion of ammonia to glutamine, which can be stored in the body or used for other anabolic processes.     

Effect of dietary vitamin C supplementation on the oxygen consumption, ammonia-N excretion and Na/K ATPase of Macrobrachium nipponense exposed to ambient ammonia

The 96-h LC₅₀ of ammonia-N and the effects of dietary vitamin C on oxygen consumption, ammonia-N excretion and Na⁺/K⁺ ATPase activity of Macrobrachium nipponense exposed to ambient ammonia were investigated. The results showed that the 96-h LC₅₀ of ammonia-N was 36.6 mg l⁻¹ for the freshwater prawn, M. nipponense, at pH 8.0. When prawns were exposed to high ambient ammonia-N concentrations, the oxygen consumption rate increased and ammonia excretion decreased. Dietary vitamin C supplementation led to higher oxygen consumption and lower ammonia excretion. Na⁺/K⁺ ATPase activity increased with increased ambient ammonia-N exposure in the range of 0–18.3 mg l⁻¹, and then was reduced at ambient ammonia-N 36.6 mg l⁻¹. Na⁺/K⁺ ATPase activities of prawns fed a vitamin C-supplemented diet were significantly lower than those of prawns fed a diet which was not supplemented with vitamin C.     

氨态氮和亚硝态氮对日本沼虾酚氧化酶活力及血蓝蛋白含量的影响

在水温(24±1)℃下分别测定了日本沼虾暴露在0、2.2、4.2、8.7、17.8、36.6 mg/L氨氮和0、2.0、3.2、5.0、7.9、13.3 mg/L亚硝酸盐后血淋巴中酚氧化酶活力和血蓝蛋白含量的变化。试验结果表明,随着氨氮和亚硝酸盐浓度的升高,酚氧化酶活力先升后降,在氨氮质量浓度为8.7 mg/L、亚硝酸盐质量浓度为5.0 mg/L时,酚氧化酶活力最高。在氨氮质量浓度为2.2 mg/L、亚硝酸盐质量浓度为2.0 mg/L时,血蓝蛋白含量显著高于对照组。日本沼虾血淋巴中酚氧化酶活力和血蓝蛋白含量没有相关性。