复合酸化剂对鲤生长及消化酶活性的影响

在鲤鱼(Cyprinus carpio)基础饲料中,分别添加不同梯度的复合酸化剂(质量分数分别为0、0.2%、0.3%),研究复合酸化剂对其生长和消化酶活性的影响。结果表明:1)添加复合酸化剂显著(P<0.05)提高鲤鱼的相对增重率、特定生长率、饵料转化效率、饲料蛋白质效率以及饲料蛋白质沉积率等生长性能指标;2)添加质量分数0.3%的复合酸化剂时,鲤鱼肝胰脏、前肠和中肠的蛋白酶活性显著提高(P<0.05),酸化剂组的淀粉酶和脂肪酶活性有升高的趋势,但与对照组差异不显著;3)鱼体的粗蛋白质、粗脂肪、粗灰分、水分、肥满度及内脏比等品质指标在各组间差异不显著。综上所述,鲤鱼饲料中添加以柠檬酸、乳酸、磷酸等为主的复合酸化剂,可显著提高鲤鱼肝胰脏、前肠和中肠的蛋白酶活性,促进鲤鱼生长。     

谷氨酰胺二肽对日本对虾血清生化指标、肝胰腺细胞凋亡及肠粘膜形态的影响

采用饲养对比试验方法,研究了谷氨酰胺二肽（Gin二肽）对日本对虾血清生化指标、肝胰腺细胞凋亡和肠绒毛的影响及对虾体健康的作用。结果表明,饲喂Gin二肽各组的PO、LSZ、ACP含量均显著（P〈0．05）高于对照组,添加0.5％和1．0％Gin二肽组的SOD和ALP含量也显著（P〈0．05）高于对照组：添加1．0％Gin二肽的TP含量显著（P〈0．05）高于其它各组。血清TP、PA、UN、CHO、PO、LSZ、SOD、ALP、ACP和LDH等各项指标均随Gin二肽添加量的提高而呈现增加趋势。试验建立了流式细胞术检测对虾肝胰腺细胞凋亡率的方法;肝胰腺细胞凋亡率随着日粮Gin二肽添加量的增加而显著降低（P〈0．05）。肠道切片显微观测结果表明,添加1．0％的Gin二肽能显著增加日本对虾肠绒毛高度（P〈0．05）。饲料中添加Gin二肽可显著提高日本对虾血清中的溶菌酶、抗氧化酶及磷酸酶活性,降低肝胰腺细胞凋亡率,增加肠绒毛高度,改善虾体健康状况。     

A sulfotransferase specific to N-21 of gonyautoxin 2/3 from crude enzyme extraction of toxic dinoflagellate Alexandrium tamarense CI01

Sulfotransferase (ST) is the first enzyme discovered in association with paralytic shellfish poisoning (PSP) toxin biosynthesis in toxic dinoflagellates. This study investigates the ST activity in crude enzyme extraction of a toxic dinoflagellate species, Alexandrium tamarense CI01. The results show that crude enzyme can transfer a sulfate group from 3’-phosphoadenosine 5’-phosphosulfate (PAPS) to N-21 in the carbamoyl group of gonyautoxin 2/3 (GTX2/3) to produce C1/C2, but is inactive toward STX to produce GTX5. The crude enzyme is optimally active at pH 6.0 and 15°C. The activity is enhanced by Co2 , Mg2 , Mn2 and Ca2 individually, but is inhibited by Cu2 . Moreover, the activity shows no difference when various sulfur compounds are used as sulfate donors. These results demonstrate that the ST specific to GTX2/3 is present in the cells of A. tamarense CI01 and is involved in PSP toxin biosynthesis. In addition, the ST from different dinoflagellates is species-specific, which explains well the various biosynthesis pathways of the PSP toxins in toxic dinoflagellates.     

草鱼、鲤鱼肠道、肝胰脏消化酶活性的初步研究

用两种不同蛋白质和糖类水平的饲料喂养草鱼、鲤鱼夏花及一龄鱼种，通过对两种鱼肝胰脏及肠道的消化酶活性测定发现，在一定温度条件下，随着水温升高，两种鱼肠道及肝胰脏的蛋白酶和淀粉酶比活均升高；鱼类摄食后六小时酶比活明显大于摄食后二十四小时的酶比活，在水温２５℃条件下，用两种不同饲料分别饲养草鱼、鲤鱼六周后发现：随着饲料蛋白质水平的提高，草鱼、鲤鱼肝胰脏中蛋白酶比活明显升高鲤，而总肠变化不显著；随饲料中糖量水平的提高，草鱼肝胰脏及肠道的淀粉酶比活明显升高，而鲤鱼差异不显著．草鱼，鲤鱼肠道蛋白酶比活以后肠最高，中肠次之，前肠最小。而肠道淀粉酶比活性却随饲料成分而发生差异。两种鱼肝胰脏消化酶活性均为一龄鱼种大于夏花阶段，这与组织切片的观察结果相符。     

Stress Responses to Rapid Temperature Changes of the Juvenile Sea Cucumber （Apostichopusjaponicus Selenka）

Activities of hexokinase （HK）, pyruvate kinase （PK）, superoxide dismutase （SOD） and catalase （CAT） and Hsp70 level were measured to evaluate the response of the commercially important sea cucumber （Apostichopus japonicus Selenka） to rapid temperature changes in laboratory. Animals were subjected to a higher temperature （from 10 to 20℃） （Tinc treatment） or to a lower temperature （from 20 to 10℃） （Tddec treatment） for 72 h. At 1, 3, 12, 24, 72 h of exposure, animals were removed and prepared for further analysis. Results showed that the effect of acute temperature changes on enzyme activities was significant. In Tinc treatment, activities of SOD and CAT increased immediately. The significant enhancement of SOD and CAT activities suggested that oxidative stress increases significantly when ambient temperature increasing from 10 to 20℃. The up-regulation of Flsp70 in Tinc and Tdec treatments indicated that Hsp70 was a bioindicator of thermal stress in the sea cucumber, and the expression pattern depended on the thermal treatment.     

松江鲈(Trachidermus fasciatus)泛素结合酶E2-D2基因的分子克隆及组织表达分析

泛素结合酶(UbcE2)是蛋白泛素化过程中所必需的酶,在泛素转移和底物的特异性识别方面发挥着重要的作用。本实验利用RACE技术克隆获得了全长为993bp的松江鲈泛素结合酶E2-D2基因cDNA序列(命名为TfUbcE2-D2),其开放阅读框为444bp,编码147个氨基酸。通过SMART预测得知,TfUbcE2-D2含有一个UBCc结构域。同源比对结果表明该基因与其他物种的同源性为92.31%。实时荧光定量PCR显示,TfUbcE2-D2广泛表达于松江鲈各组织,在肾脏中的相对表达量最高,其次为鳃。鳗弧菌(Vibrio anguillarum)刺激后,TfUbcE2-D2在血液、脾脏、肝脏和鳃中表达均上调,其中,脾脏和鳃中的表达量上调约40倍。由以上实验结果推测,TfUbcE2-D2可能参与松江鲈的先天免疫防御。     

不同光照周期对刺参摄食节律和消化生理的影响

在实验室条件下,研究了全光照(24L︰0D)、半光照半黑暗(12L︰12D)、全黑暗(0L︰24D)3种光照周期下刺参(Apostichopus japonicus)的摄食节律、摄食率以及3种消化酶(脂肪酶、淀粉酶、胰蛋白酶)活力的昼夜变化规律。结果显示:(1)在全光照条件下,刺参极少活动,24 h内的摄食比例较低(6%~10%);在半光照半黑暗条件下,刺参光照阶段运动不活跃,摄食比例较低(0~10%),黑暗阶段运动极其活跃,摄食比例较高;在全黑暗条件下,刺参一直处于较活跃状态,24 h内的摄食比例都较高。3种光照条件下,刺参的摄食高峰都出现在00:00~02:00,且刺参夜晚的摄食比例显著高于白天(P0.05);(2)刺参的日摄食率从全光照、半光照半黑暗到全黑暗依次增加,3种光照周期条件下刺参夜晚的摄食率极显著高于白天的摄食率(P0.01);(3)3种光照周期下,刺参3种消化酶活力的最大值都出现在22:00~02:00,消化酶活力的最大值比摄食高峰早0~4 h。研究结果表明,光照对刺参的摄食节律和消化酶活力昼夜变化都有显著影响,刺参具有提前分泌消化酶为即将到来的摄食做好准备的调节机制。     

三种红树根部组织抗氧化酶活性对水淹胁迫的响应

以自然种群高程分布为根据, 选择对潮汐浸泡耐性存在一定差异的白骨壤(Avicennia marina)、桐花树(Aegiceras corniculatum)和木榄(Bruguiera gymnorrhiza)为实验树种。对3种红树幼苗进行为期0d、1d、3d、5d、7d、14d的水淹处理, 测定其根部组织的过氧化物酶(peroxidase, POD)活性、超氧化物歧化酶(superoxide dismutase, SOD)活性、抗坏血酸氧化酶(ascorbic acid oxidase, APX)活性和过氧化氢酶(catalase, CAT)活性。水淹处理会导致植物根部组织受低氧胁迫从而破坏活性氧(reactive oxygen species, ROS)生产和消除的平衡, ROS大量累积给植物带来氧化损伤。实验测定与清除ROS有关的酶指标, 结果表明POD活性在1d至14d的水淹周期内随时间呈现上升趋势, 这可能与POD参与活性氧以及乙醇、乳酸等有毒物质的反应有关。CAT、SOD、APX活性均呈现应激上升后下降趋势, 由此推断该系列抗氧化酶在水淹胁迫发生前中期对消除红树植物根部组织大量产生的活性氧具有重要意义。抗氧化酶系在3种红树植物中的表达存在一定差异, 但整体仍呈相似的变化趋势。通过层次聚类法对各项酶活性指标分析后发现, 白骨壤抗氧化酶系的活性模式与木榄和桐花树的存在一定差异, 但没有发现木榄与桐花树抗氧化酶系统表达模式的明显差异。本研究旨在更好地了解红树林对水淹胁迫的生理适应机制, 为红树林生态系统保护与管理提供理论依据。     

南极菲尔德斯半岛潮间带沉积物细菌的多样性及分离菌产酶测定

摘要:南极菲尔德斯半岛具有多种不同特征的生态地理微环境,如长城科考站、企鹅岛、生物湾与黄金湾流域、半岛南部、碧玉滩等。这些区域因水文地质、动植物分布、人类活动程度等不同而具有明显的生态地理差异。本研究从这些微环境海岸潮间带采集了7份代表性沉积物样品,采用16S rRNA基因高通量测序方法,对其细菌类群的多样性以及环境理化因子的影响进行了比较分析;同时采用常规可培养鉴定方法,对样品的分离菌株产酶状况进行了初步测定。结果表明：整体上看,所有样品的细菌类群主要分布在45门、104纲、442属当中,表现出比较高的多样性。其中,优势菌门Proteobacteria主要分布在半岛南部、碧玉滩和生物湾潮间带沉积物物中,优势菌门Bacteroidetes主要分布在企鹅岛两侧和黄金湾潮间带沉积物,长城站潮间带沉积物的优势门为Firmicutes。相似生态微环境的潮间带沉积物具有不同的优势菌门和纲;而不同生态微环境潮间带沉积物却具相同的优势菌门和纲。有机氮（TON）、NH4+-N、NO3--N、PO43--P、NO2--N含量与企鹅岛两侧、生物湾、黄金湾潮间带沉积物的菌群多样性具有相关性,其中TON对生物湾样品的影响最大,而有机碳（TOC）对所有样品的影响较小。分离菌株的产酶实验表明：在企鹅岛、生物湾、黄金湾等动物频繁出没的潮间带样品中,蕴藏着一批产淀粉酶、酪蛋白酶、脂肪酶、七叶苷酶、过氧化氢酶能力较强菌株,这为今后进一步的应用开发提供了宝贵的低温产酶菌株来源。 关键词: 菲尔德斯半岛; 潮间带沉积物; 细菌类群多样性; 产酶菌株     

Effects of Pseudoalteromonas sp. BC228 on digestive enzyme activity and immune response of juvenile sea cucumber (Apostichopus japonicus)

A marine bacterium, Pseudoalteromonas sp. BC228 was supplemented to feed in a feeding experiment aiming to determine its ability of enhancing the digestive enzyme activity and immune response of juvenile Apostichopus japonicus. Sea cucumber individuals were fed with the diets containing 0(control), 105, 107 and 109 CFU g-1 diet of BC228 for 45 days. Results showed that intestinal trypsin and lipase activities were significantly enhanced by 107 and 109 CFU g-1 diet of BC228 in comparison with control(P 0.01). The phagocytic activity in the coelomocytes of sea cucumber fed the diet supplemented with 107 CFU g-1 diet of BC228 was significantly higher than that of those fed control diet(P 0.05). In addition, 105 and 107 CFU g-1 diet of BC228 significantly enhanced lysozyme and phenoloxidase activities in the coelomic fluid of sea cucumber, respectively, in comparison with other diets(P 0.01). Sea cucumbers, 10 each diet, were challenged with Vibrio splendidus NB13 after 45 days of feeding. It was found that the cumulative incidence and mortality of sea cucumber fed with BC228 containing diets were lower than those of animals fed control diet. Our findings evidenced that BC228 supplemented in diets improved the digestive enzyme activity of juvenile sea cucumber, stimulated its immune response and enhanced its resistance to the infection of V. splendidus.