香港巨牡蛎与长牡蛎种间配子兼容性

为了评估香港巨牡蛎与长牡蛎的配子兼容性,于2010年7月,以性腺成熟的香港巨牡蛎和长牡蛎为材料,研究了环境因子温度(16、20、24、28、32℃)、盐度(10、15、20、25、30)及内在因子精子浓度(100、101、102、103、104个/μL)、个体差异(240次杂交实验)对其受精率的影响,并计算了以上条件下的F50临界值。结果表明:香港巨牡蛎卵子可以与长牡蛎精子受精,但相反方向不能受精,存在着单向受精现象。温度是影响长牡蛎配子兼容性主要因子,盐度是影响香港巨牡蛎的主要因子,而温度、盐度交互作用是影响种间配子兼容性的最主要因子。种间配子温度、盐度的F50临界值分别为20.90℃、14.7。精子浓度及单对杂交中的个体差异均显著影响配子兼容性,精子浓度的F50临界值为2.40个/μL;在240次杂交实验中,有91次受精率不足50%,说明个体差异比例的F50临界值37.92%。从其内在因子来看,长牡蛎平均受精率最高(96.83%),配子兼容性较好;对于香港巨牡蛎(70.98%)与种间配子(58.70%)而言,受精水平相对较低,且存在着较大的个体差异。     

锈赤扁谷盗成虫趋光行为研究

【目的】研究灯光诱捕技术防治锈赤扁谷盗Cryptolestes ferrugineus(Stephens)的可行性。【方法】在实验室条件下测定了锈赤扁谷盗成虫对不同光源的趋光反应。【结果】锈赤扁谷盗成虫对实验所选取的光源都有一定的趋性。在可见光中,对主波长为575 nm的光源的趋性最强,对430、495、620、530和450 nm光源的趋性依次降低。在紫外光中,对主波长为385 nm的光源的趋性显著高于对主波长为365、375和395 nm的光源;1~10日龄的锈赤扁谷盗成虫,随日龄的增加,成虫趋光性先增强后有所减弱;雌虫的趋光性高于雄虫,且交配状态会影响雌虫和雄虫的趋光性。交配会抑制雄虫的趋光性,但是交配后的雌虫的趋光性增强;短期饥饿处理和灯光经历对害虫趋光性无显著影响。【结论】锈赤扁谷盗成虫对光波长的选择偏好性证实了其灯光诱捕技术的可行性。     

温度和盐度对缢蛏浮游幼虫发育的影响

本文叙述了在室内控制条件下,温度和盐度单因子及其结合对缢蛏浮游幼虫的影响。缢蛏浮游幼虫生长发育的适温范围为17°—32℃,其中以25°—27℃为最好。对高温和低温有较强的耐力,致死温度的上限为40℃左右,变态的下限水温为15℃左右,幼虫适盐范围是4.50—28.30‰,其中以12.40‰为最适宜,但幼虫对低盐度的耐力比对较高盐度的耐力强。 温度对缢蛏浮游幼虫期的长短、增长速度和存活率的影响,要比盐度对它的影响显著,而盐度对缢蛏幼虫变态率的影响却比温度重要些。温度与盐度对缢蛏浮游幼虫发育影响的相关性不明显。     

温度和盐度对缢蛏浮游幼虫发育的影响

本文叙述了在室内控制条件下,温度和盐度单因子及其结合对缢蛏浮游幼虫的影响。缢蛏浮游幼虫生长发育的适温范围为17°—32℃,其中以25°—27℃为最好。对高温和低温有较强的耐力,致死温度的上限为40℃左右,变态的下限水温为15℃左右,幼虫适盐范围是4.50—28.30‰,其中以12.40‰为最适宜,但幼虫对低盐度的耐力比对较高盐度的耐力强。 温度对缢蛏浮游幼虫期的长短、增长速度和存活率的影响,要比盐度对它的影响显著,而盐度对缢蛏幼虫变态率的影响却比温度重要些。温度与盐度对缢蛏浮游幼虫发育影响的相关性不明显。     

香港巨牡蛎和长牡蛎幼虫及稚贝的表型性状

为了评估香港巨牡蛎和长牡蛎在北方沿海的早期表型性状,于2010年7月,以2009年6月在青岛繁育的两种牡蛎为材料,在大连研究了温度(Mt:(22±1.0)℃及Ht:(28±1.0)℃)、盐度(S₂₀:20±1.0及S₃₀:30±1.0)及中间育成环境(ID:室内及OD:室外)对两种牡蛎幼虫及稚贝表型性状的影响。结果表明:香港巨牡蛎壳宽显著大于长牡蛎(P<0.05),壳高及怀卵量显著小于长牡蛎(P<0.05),壳长、鲜重及壳重两者间无显著差异(P>0.05)。在温度和盐度相同情况下,长牡蛎卵径、受精率、孵化率及D形幼虫均大于香港巨牡蛎;香港巨牡蛎幼虫浮游前期生长较慢,而后快于长牡蛎。两种牡蛎幼虫存活能力在15日龄时高温组>中温组;相同温度下,香港巨牡蛎中盐组>高盐组,长牡蛎高盐组>中盐组。幼虫变态期间,较低的温度延迟了变态时间,降低了变态率,使得两种幼虫变态规格大型化。温度是影响幼虫生长、存活、变态的最主要因素,其次为盐度,交互作用几乎尚未起到作用。中间育成阶段,室外比室内培育效果更好,且香港巨牡蛎稚贝壳高在60日龄以后显著大于长牡蛎(P<0.05),环境是影响稚贝生长的最主要因素;无论室内还是室外两种牡蛎稚贝的存活率均在90%以上,且各实验组间无显著差异(P>0.05)。     

盐度和温度对不同规格虎斑乌贼幼体的耗氧率、排氨率和窒息点的影响

为探究体重、盐度和温度对不同规格的虎斑乌贼(Sepia pharaonis)幼体耗氧率、排氨率以及其窒息点的影响。采用单因子试验设计和密闭静水法, 对不同体重下(0.212、0.385、0.476、0.597、0.754和0.946 g)虎斑乌贼幼体的耗氧率和排氨率, 以及不同体重(0.476、0.673、1.341、3.873和4.205 g)幼体的窒息点进行了测定, 同时研究了不同盐度(19‰、22‰、25‰、28‰和31‰)和温度(18、21、24、27和30℃)对不同规格[A: 体重(0.366±0.042) g, B: 体重(0.556±0.038) g, C: 体重(0.844±0.051) g]的虎斑乌贼幼体耗氧率(R_O)和排氨率(R_N)的影响。结果表明: (1)虎斑乌贼幼体体重对耗氧率和排氨率均影响显著(P<0.05)。随着幼体体重的增长, 耗氧率和排氨率显著下降, 个体越小耗氧率和排氨率越大; (2)盐度对幼体的耗氧率和排氨率有显著影响(P<0.05), 均随着盐度的增加呈先下降后上升的趋势, 其中, A规格和B规格的幼体在盐度25‰时, 耗氧率和排氨率显著低于盐度19‰、22‰和31‰时的3个试验组(P<0.05), 而与盐度28‰时无显著差异(P>0.05); C规格幼体的耗氧率在盐度28‰时显著低于盐度19‰组(P<0.05), 而排氨率在盐度25‰时显著低于盐度19‰和31‰两组(P<0.05)。盐度对A规格幼体的氧氮比(O/N)值有显著影响(P<0.05), 而对B规格和C规格的幼体无显著影响(P>0.05)。(3)温度对不同规格幼体的耗氧率和排氨率有显著影响(P<0.05), 均随温度的增长, 呈先上升后下降的趋势。其中, A规格和C规格幼体的耗氧率在27℃时, 显著高于18和30℃两组(P<0.05), B规格的在水温24℃时显著高于18和30℃(P<0.05); A规格和B规格幼体的排氨率分别在24和27℃时, 显著高于其他温度组(P<0.05), C规格的在温度27℃时, 显著高于18和30℃两组(P<0.05); 温度对A规格幼体的O/N值有显著影响(P<0.05), 而对B规格和C规格的幼体无显著影响(P>0.05)。(4)虎斑乌贼幼体的窒息点为0.84—1.62 mg/L, 随着体重的增加而逐渐降低。     

近零磁场对褐飞虱翅型分化、趋光性及飞行能力的影响

【目的】地磁场(geomagnetic field,GMF)不是恒定不变的,而是随时间和空间时刻变化的。目前,动物对磁场变化的响应研究主要集中于迁徙性动物地磁定向导航中的磁感受方面,而迁徙性动物迁出地和迁入地之间地磁场强度差异对动物生理和行为潜在的磁场效应尚不明确。【方法】迁飞性昆虫褐飞虱Nilaparvata lugens试虫采自江苏省农业科学院试验田。本文采用亥姆霍兹线圈室内模拟近零磁场(near-zero magnetic field,NZMF)和GMF,调查了褐飞虱成虫在NZMF和GMF下的翅型分化、趋光性和飞行能力。【结果】结果表明,与GMF相比,NZMF显著提高了褐飞虱雄成虫短翅型比例(6. 4%)(P <0. 05),但对雌成虫长翅型比例影响不显著(P> 0. 05);对于长翅雌成虫,NZMF显著提高了其2日龄成虫的上灯比例(55%)(P <0. 05),但显著降低了其4日龄成虫的上灯比例(22%)(P <0. 05),对趋光性的影响总体呈现出随着龄期先增强后减弱的效应。NZMF对长翅雄成虫趋光性的影响也呈现出相同的效应,但对各日龄成虫的影响不显著(P> 0. 05); NZMF显著缩短了2日龄长翅雄成虫的飞行时间(46%)(P <0. 05),并显著提高了长翅雌成虫(65%)和长翅雄成虫(101%)的飞行速度(P <0. 05)。此外,GMF对照组的褐飞虱长翅雄成虫飞行速度显著低于长翅雌成虫(96%),而NZMF处理组中二者无显著差异。【结论】结果说明,近零磁场可提高褐飞虱成虫短翅比例,对长翅成虫趋光性的影响呈现出基于龄期增长先增强后减弱的效应,并在未影响长翅成虫飞行距离的情况下,改变了其飞行策略,即提高飞行速度,同时缩短飞行时间。     

梨小食心虫对LED光的趋性及影响因素的研究

为了明确梨小食心虫Grapholita molesta Busck对LED光的趋性及果园利用LED光诱捕梨小食心虫的效果,为开发基于梨小食心虫趋光行为的新防治手段提供依据。本研究通过室内观察梨小食心虫成虫对不同波长的4种LED光及白光的趋性及暗适应时间、性别、日龄和光照强度对趋光性的影响,进一步调查了LED光对田间梨小食心虫成虫的诱捕效果。结果表明:在室内条件下,梨小食心虫成虫对520 nm的绿光趋性最强。1⁵日龄成虫中,以3日龄成虫趋光性最强,且雌虫趋光性显著高于雄虫。在暗适应0.55日龄成虫中,以3日龄成虫趋光性最强,且雌虫趋光性显著高于雄虫。在暗适应0.5³.0 h范围内,梨小食心虫成虫的趋光性表现为"抛物线形",以暗适应2.0 h时趋光性最强,并显著高于其它暗适应处理时间。在550、650、750、850 lx光照强度下,以650 lx光强时的趋光性最强。田间诱捕结果表明,不同颜色的LED灯对梨小食心虫的诱捕效果均不理想,不适于梨小食心虫的防治。     

昆虫趋光性及其机理的研究进展

依据目前已有资料 ,从行为学、生理学及田间应用调查等方面概述了近几十年昆虫趋光性的国内外研究进展。其中 ,行为学与生理学研究较多 ,且两者结果基本一致 ,相互补充 ,为趋光性机制的假说提供了可靠的依据。关于昆虫趋光性机制的假说较多 ,其中报道较多的是光干扰假说、光定向行为假说和生物天线假说 3种 ,现在较为普遍接受的是前两者。光干扰假说是指刺眼作用干扰昆虫的正常活动导致趋光 ,而光定向行为假说则指昆虫趋光是由于光定向行为所致     

光谱和性别对几种金龟子趋光行为的影响

本研究采用不同波长的LED新型绿色光源对几种金龟子雌雄性的趋光行为进行研究,结果表明:棕色鳃金龟Holotrichia titanis Reitter、铅灰鳃金龟H.plumbeaHope、铜绿丽金龟Anomala corpulenta Motschulsky的趋光反应率分别为68%、84%、90%,显著高于暗黑鳃金龟H.parallela Motschulsky和大黑鳃金龟H.oblita Hope;棕色鳃金龟和铅灰鳃金龟趋光谱较广;主峰为405nm和465nm的单色光对所有试虫均有较强的诱集力。雌性大黑鳃金龟和暗黑鳃金龟的趋光性强于雄虫;但雌雄差异对棕色鳃金龟、铅灰鳃金龟和铜绿丽金龟的趋光性无显著影响。     

Effects of temperature and salinity on haemocyte activities of the Pacific oyster, Crassostrea gigas (Thunberg)

The Pacific oyster, Crassostrea gigas, is extensively cultivated and represents an important economic activity. Oysters are reared in estuarine areas, subjected to various biotic and abiotic factors. One of the limiting factors in aquaculture is mortality outbreaks, which may limit oyster production, and the causes of these outbreaks are not completely understood. In this context, the effects of temperature and salinity on Pacific oyster, C. gigas, haemocytes, were studied. Haemocytes are the invertebrate blood cells and thus have been shown to be involved in defence mechanisms. Flow cytometry was used for monitoring several haemocyte parameters. An increase of temperature induced an increase of haemocyte mortality, in both in vitro and in vivo experiments. Temperature modulated aminopeptidase activity. An in vitro decrease of salinity was associated with cell mortality. During the course of in vivo experiments, an increase of phagocytic activity was reported at 15 per thousand and 50 per thousand. Environmental physical parameters may modulate haemocyte activities.     

Polymorphism of metallothionein genes in the Pacific oyster Crassostrea gigas as a biomarker of response to metal exposure.

Quantification of metallothioneins (MTs) is classically associated with a cellular response to heavy metal contamination and is used in the monitoring of disturbed ecosystems. Despite the characterization of several MT genes in marine bivalves, only a few genetic studies have used MT genes as potential biomarkers of pollution. The aim of this study was to assess whether MT gene polymorphism could be used to monitor exposure of the Pacific oyster Crassostrea gigas to heavy metals and to develop specific genetic markers for population genetic studies in relation to environmental stress. The polymorphism of two exons of the C. gigas MT gene CgMT1 were studied using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) in both field populations exposed to various metals concentrations and in experimentally exposed populations. High frequencies of two SSCP types in exons 2 and 3 of the CgMT1 gene have found to be significantly associated with tolerance to metals in experimental and field oyster populations. The use of MT1 gene polymorphism in C. gigas as in the present study should therefore be of high ecological relevance. In conclusion, the analysis of the types in these two CgMT1 gene exons, which can confer a greater tolerance to heavy metals, can constitute a good biomarker of effect of the presence of heavy metals in ecosystems.     

Evaluation of biomarkers in oyster larvae in natural and polluted conditions

Crassostrea gigas D-shaped larvae were subjected to different conditions of temperature and salinity for 24 h and four biomarkers (acetylcholinesterase (AChE) activity, thiobarbituric acid reactive substances (TBARS) levels, glutathione S-transferase (GST) and catalase (CAT) activities) were measured. AChE activity decreased when salinity increased from 25 to 30 and 35 psu at 20 and 25 degrees C. Temperature did not seem to have an influence on AChE activity. TBARS levels increased as a function of salinity when the temperature was maintained at 20 degrees C, whereas at 25 degrees C no effect of salinity could be observed. Variations in GST and CAT activities were not significant with salinity and temperature except that catalase activity was higher at 25 degrees C than at 20 degrees C. Exposure experiments were conducted at 23 degrees C and 30 psu with carbofuran (100 and 1000 microg/l) and malathion (100 and 300 microg/l). There was an inhibition of AChE activity with carbofuran, and a toxic effect shown by an increase in TBARS levels counteracted by increases in GST and CAT activities which protected the larvae. When two pairs of adults producing larvae were taken into consideration, significant differences in biomarker levels were noted between the larval offspring of each pair. Malathion induced a decrease in AChE activity and an increase in CAT activity.     

在沉积物暴露条件下2种海洋贝类对Cu、Pb 的富集动力学研究

首次通过构建海水-底泥-生物体体系,应用半静态双箱动力学模型室内模拟了沉积物暴露条件下文蛤(Meretrix meretrix)和缢蛏(Sinonovacula constricta)对Cu、Pb的生物富集实验,通过对富集与排出过程中文蛤体内重金属污染物的动态监测和对富集与排出过程监测结果的非线性拟合,得到了文蛤和缢蛏富集重金属的吸收速率常数K1、排出速率常数K2、生物富集因子BCF、富集平衡浓度CAmax、生物学半衰期B1/2等动力学参数。拟合结果得到的Cu、Pb各动力学参数分别为:文蛤K1为4.63—69.41,K2为0.05—0.08,CAmax为9.83—40.57,BCF为60.77—1444.56,B1/2为9.09—14.43;缢蛏K1为4.27—122.92。K2为0.05—0.07。CAmax为5.12—32.84。BCF为65.68—2112.02。B1/2为9.81—14.15。对模型的拟合优度检验结果显示,在沉积物暴露条件下文蛤和缢蛏对重金属Cu、Pb的生物富集数据符合双箱模型,模型的拟合优度良好。比较结果得出:吸收速率常数K1及生物富集因子BCF均随着外部水体金属暴露浓度的增大而减小;CAmax均随着外部水体金属暴露浓度的增大而增大;文蛤和缢蛏对Cu富集能力大于Pb;Cu在文蛤和缢蛏体内的生物学半衰期B1/2大于Pb;理论平衡状态下文蛤和缢蛏体内Cu、Pb的含量CAmax随着外部水体中金属暴露浓度的增大而增大,且呈显著正相关,实验结果表明在沉积物暴露条件下双箱动力学模型在一定条件下是可以应用于文蛤和缢蛏的富集动力学研究的,但仍需要进一步开展在不同条件下实验研究分析。     

Response of haemocyte lysosomes to bacterial inoculation in the oysters Ostrea edulis L. and Crassostrea gigas (Thunberg) and the scallop Pecten maximus (L)

Data are presented that demonstrate the application of the neutral red retention assay (NRR) to monitor the effects of a bacterial inoculation on the haemocyte lysosomes of the European flat oyster Ostrea edulis, Pacific oyster Crassostrea gigas and scallop Pecten maximus. Bivalves were acclimated to three temperature regimes (5, 15 and 25 degrees C), at constant salinity for 7 days in the laboratory. Once baseline responses to acclimation temperature had been established, the effects of an in vivo inoculation on haemocyte lysosomal stability were assessed using the NRR assay. Lysosomal membrane stability was reduced in the presence of bacteria for all three species of bivalve, but destabilisation of C. gigas haemocyte lysosomes appeared to be most sensitive to the presence of the bacterium Listonella anguillarum. For all three bivalve species, the reduction in lysosomal stability appeared to be proportional to the growth of the bacterial inoculate. Using appropriate controls, the NRR assay was demonstrated to have great potential as a tool with which to make rapid initial assessments of the immune status of bivalve molluscs.     

Toxicity to bivalve hemocytes of pathogenic vibrio cytoplasmic extract

Using a chemiluminescence (CL) test, it had been previously demonstrated that Vibrio pectenicida, which is pathogenic to Pecten maximus larvae, was able to inhibit completely the CL activity of P. maximus hemocytes and partially inhibit those of Crassostrea gigas. Conversely, a Vibrio sp. strain, S322, pathogenic to C. gigas larvae was more active in reducing the CL activity of oyster hemocytes than of scallop hemocytes. Using this same CL biotest, V. pectenicida and S322 cytoplasmic extracts were shown to reproduce CL inhibition while the cytoplasmic extract of a nonpathogenic strain (U1, Pseudoalteromonas) was without effect. Moreover, cytoplasmic extract as well as live V. pectenicida cells provoked, within a few hours, death of P. maximus hemocytes adhering to a glass slide. After partial purification, it was shown that toxic activities of V. pectenicida cytoplasmic extract was due to a toxin, named VHKT (for vibrio hemocyte-killer toxin), which is heat stable, acid and protease resistant, and less than 3 kDa in molecular weight. Attempts to purify VHKT by reverse-phase (C18) HPLC separated activity into the fraction eluted by water at a retention time of 4.02 min.     

The extracellular metalloprotease of Vibrio tubiashii is a major virulence factor for pacific oyster (Crassostrea gigas) larvae

Vibrio tubiashii is a recently reemerging pathogen of larval bivalve mollusks, causing both toxigenic and invasive disease. Marine Vibrio spp. produce an array of extracellular products as potential pathogenicity factors. Culture supernatants of V. tubiashii have been shown to be toxic to oyster larvae and were reported to contain a metalloprotease and a cytolysin/hemolysin. However, the structural genes responsible for these proteins have yet to be identified, and it is uncertain which extracellular products play a role in pathogenicity. We investigated the effects of the metalloprotease and hemolysin secreted by V. tubiashii on its ability to kill Pacific oyster (Crassostrea gigas) larvae. While V. tubiashii supernatants treated with metalloprotease inhibitors severely reduced the toxicity to oyster larvae, inhibition of the hemolytic activity did not affect larval toxicity. We identified structural genes of V. tubiashii encoding a metalloprotease (vtpA) and a hemolysin (vthA). Sequence analyses revealed that VtpA shared high homology with metalloproteases from a variety of Vibrio species, while VthA showed high homology only to the cytolysin/hemolysin of Vibrio vulnificus. Compared to the wild-type strain, a VtpA mutant of V. tubiashii not only produced reduced amounts of protease but also showed decreased toxicity to C. gigas larvae. Vibrio cholerae strains carrying the vtpA or vthA gene successfully secreted the heterologous protein. Culture supernatants of V. cholerae carrying vtpA but not vthA were highly toxic to Pacific oyster larvae. Together, these results suggest that the V. tubiashii extracellular metalloprotease is important in its pathogenicity to C. gigas larvae.     

非生物因子对河蚬重金属富集量的影响

对影响长江口滨岸带河蚬体内重金属富集量的4个主要非生物因子依次进行分析。结果表明,较高温度有助于河蚬对Cu、Zn、Cr、Ni的吸收;盐度对河蚬的重金属累积量影响比较复杂,仅在秋季表现出一定相关性,春季盐度影响不大;河蚬体内Cu含量与沉积物粒径存在显著正相关,Zn与沉积物中有机质含量存在一定正相关,Pb与沉积物中有机质含量存在着负相关;河蚬体内重金属元素两两间的相关性明显,多种元素间的相互作用机理值得进一步探讨。