基于眼柄微结构的克氏原螯虾生长分析

甲壳类的蜕壳生长机制使其能够记录生物学信息的钙化组织周期性消失。一直以来,甲壳类年龄和生长的研究都是一个比较棘手的问题。本文观察和分析了采集于上海浦东新区南汇新城镇河道的克氏原螯虾(Procambarus clarkii)的眼柄微结构,并研究了其眼柄上的生长纹与体长、体质量的关系。结果显示,克氏原螯虾眼柄切片的横截面和纵切面均可观察到其微结构由表层、色素层、钙化层和膜层等4部分组成;眼柄内存在明暗相间的生长纹,样本生长纹的数目范围为8~31个;生长纹间距由色素层与钙化层的交界处到钙化层与膜层的交界处呈现出由宽到窄的变化趋势。克氏原螯虾眼柄的生长纹数目与其体长、体质量的Logistic关系式分别为L=(96.66)/(1+e~(-0.25(t-2.54)))、W=(22.48)/(1+e~(-0.41(t-11.78)))。     

An Analytical Model for Predicting the Carrying Capacity of Submerged Biofilters Used in Aquaculture

Laboratory data and information from the literature were used to develop an equation that models ammonia removal by submerged biofilters. The equation is based on the half-order/zero-order kinetics model and fixed biofilm nitrification, which indicates that the nitrification rate is a linear function of the ammonia concentration at ammonia concentrations <2.0 mg/l. Input data for the equation include easily gathered information of flow rate, biofilter size, maximum permissible ammonia level, biofilter influent and biofilter effluent ammonia concentrations, temperature, and ammonia production rate. The equation can be used to determine the carrying capacity of the submerged biofilters, to estimate biofilter sizes needed to support various fish loads, and to investigate the effects of changes in biofilter system parameters on carrying capacity. Comparisons of the predicted and actual carrying capacities of several experimental biofilters indicated that the equation accurately predicted carrying capacity under most conditions. Studies of the sensitivity of the equation to changes in system parameters demonstrated that flow rate limits biofilter performance and suggested an approach for determining cost-effective flow rates for biofilter operation.     

Haemolymph metabolic variables in relation to eyestalk ablation and gonad development of Pacific white shrimp Litopenaeus vannamei Boone

The present study analyses some biochemical variables in haemolymph proposed as predictive indicators of the maturation capability following eyestalk ablation. Haemolymph of captive females was obtained before and 8 days after eyestalk ablation, and levels of haemocyanin, total proteins, glucose, lactate, cholesterol, triacylglycerides and vitellogenin were determined. Biochemical variables were also analysed in the hepatopancreas at the end of the experiment. Females were grouped as immature (previtellogenic stage) and mature (vitellogenic and cortical stages) based on histological analysis done 8 days after eyestalk ablation. To analyse haemolymph variables before eyestalk ablation in relation to maturation capability, immature females were classified as those with a low maturation capability and mature females as those with a high maturation capability. Females of high maturation capability had significantly higher vitellogenin levels before eyestalk ablation than females of low maturation capability. No significant differences were found for the other biochemical variables. Vitellogenin was also higher in mature than in immature females at the end of the experiment. These results indicate that vitellogenin levels in haemolymph could be used as possible predictive criteria of maturation capability, possibly because they reflect the degree of ovarian development at the time of eyestalk ablation.     

中华绒螯蟹眼柄神经内分泌系统的组织学研究

应用组织切片技术于光镜下研究了中华绒螯蟹眼柄神经内分泌系统的组织形态结构,眼柄神经内分泌系统的主要组成部分为Ｘ器官－窦腺复合体Ｘ器官位于视端髓的外缘,其内具有Ｉ型和Ⅱ型两种类型神经分泌细胞,窦腺位于视内髓与视端髓交界处的背部,与Ｘ器官处于不同侧,由窦腺壁与中央血窦腔组成,窦腺壁由神经分泌细胞的末梢及神经质细胞交织而成。此外,在窦腺周围还存在的Ⅲ型和Ⅳ型神经分泌细胞及一群未知细胞团。     

Enhancement of reproductive performance in shrimp Litopenaeus vannamei (Boone, 1931) by supplementation of Ulva clathrata meal in maturation diet in two commercial hatcheries

The effect of supplementing dehydrated seaweed Ulva clathrata (20 g/kg) in the squid fraction of a formulated fresh diet on the reproductive performance of Litopenaeus vannamei broodstock was evaluated in two commercial hatcheries (A and B). The origin of broodstock, use of ablation on females, tank/culture conditions (for maturation, spawning, and larval rearing) were different between hatcheries. Daily mortality was higher (p < .01) for females in the control group compared to Ulva‐fed group of hatchery A, where females were ablated. No differences in mortality were found for unablated females in hatchery B, or with males from either hatchery. In hatchery A, broodstock fed Ulva produced more eggs (an increase in +5% compared to control, p < .05) and nauplii per female (+18%, p < .01). In hatchery B, broodstock fed Ulva produced significantly more eggs (+26%, p < .05) and nauplii per day (+33%, p < .05). In hatcheries A and B, eggs from broodstock fed Ulva had increased hatching rates (+13 and +7%, respectively, p < .001 in both cases). The number of spawns per day had a tendency to be higher in broodstock fed Ulva in both hatcheries, but the difference did not reach statistical significance (+14% for hatchery A and +20% for hatchery B). Dehydrated U. clathrata appears therefore as a functional additive in L. vannamei maturation diets that enhances the reproductive performance at commercial scale, regardless of the management conditions.     

三疣梭子蟹细胞Cdk7基因克隆及其在卵巢发育中的表达

本实验应用RACE技术克隆获得了三疣梭子蟹(Portunus trituberculatus)周期蛋白依赖性激酶7(Cdk7)基因c DNA序列全长。基因5′和3′非编码区域(UTR)以及开放阅读框的长度分别是23 bp、178 bp和1056 bp,预测编码一个含有351个氨基酸,分子量为39.91 k D的蛋白质,包含一个丝氨酸/苏氨酸催化保守结构域和T-loop结构。同源性分析表明,三疣梭子蟹CDK7氨基酸序列与其他物种Cdk7相似度较高,说明Cdk7基因具有很好的保守性。实时荧光定量PCR结果显示,三疣梭子蟹Cdk7基因在卵巢组织中的表达量显著高于其他组织(P0.05)。Cdk7基因在卵巢发育不同时期的表达量存在差异,其在I期和Ⅱ期的表达量显著高于其他时期(P0.05)。去除眼柄后该基因在卵巢组织中的表达呈现先升高后降低的趋势,并于第4天达到最大值。本研究的结果表明,Cdk7基因参与了三疣梭子蟹卵巢发育调控,为深入开展三疣梭子蟹和其他甲壳动物性腺发育调控机理研究提供了重要信息。     

红螯螯虾XO-SG神经细胞的原代培养

本研究采用酶解的方法获得红螯螯虾眼柄XO-SG复合体的单个神经细胞,并依据显微观察对XO-SG神经细胞进行分类,同时利用Leibovitz's L-15等作为基础培养基离体培养解离的神经细胞。目的是建立虾类XO-SG神经细胞的分类标准并确定合适的培养条件,便于在体内外开展神经内分泌系统的调控研究。结果显示,根据神经细胞形态特点,红螯螯虾XO-SG神经内分泌细胞分为6种类型,不同类型的细胞在细胞大小以及显微结构上存在明显差异;建立了红螯螯虾眼柄XO-SG神经元的体外原代培养方法,细胞在改良的L-15培养基中存活状态良好,原代培养的神经细胞可以在体外存活14 d。离体培养过程中,不同类型神经细胞的再生速率存在差异,部分细胞在第2天就出现再生的轴突或树突。再生过程基本可以持续7 d,随后细胞开始萎缩凋亡。本研究为红螯螯虾眼柄神经细胞的分类以及利用神经细胞在体外开展虾类的内分泌代谢和调节机制研究提供了基础依据和研究平台。     

Stimulation of ovarian growth by methyl farnesoate and eyestalk ablation in penaeoidean model shrimp,Sicyonia ingentis Burkenroad, 1938

The effect of methyl farnesoate (MF) administration on the vitellogenesis of the penaeoidean shrimp, Sicyonia ingentis, was studied. The short‐ and long‐term treatment effects as well as the effect of two MF injection regimens (0.1 and 1.0 μg MF/injection) were evaluated. The studies were also carried out to understand the pattern of vitellogenesis in eyestalk ablated adult and juvenile shrimps. A combination of endpoints, haemolymph vitellogenin (Vg) levels, gonadosomatic index (GSI) and histology, was used to study the effect of these treatments. The GSI increased in all the MF‐treated shrimp compared with the control shrimps. Although haemolymph Vg levels declined over the experimental period in all the treatments, the Vg levels decreased significantly only in the short‐term treatment with 1.0 μg MF. Similarly, haemolymph protein level also declined over the experimental period in all the treatment groups. However, except in the long‐term treatment with 0.1 μg MF, all treatments showed a significant decrease in haemolymph protein level. Conversely, in all eyestalk ablated adults and juveniles, haemolymph Vg, total protein and GSI increased over the experimental period, all of which were higher than the concurrent control. The discrepancy in the vitellogenic pattern between MF‐treated and eyestalk ablated shrimp was possibly due to the difference in the ovarian phase of the initial control. Although unilateral eyestalk ablation failed to induce vitellogenesis in juveniles, bilateral ablation induced vitellogenesis, which indicates that juveniles are competent to undergo vitellogenesis.     

中华绒螯蟹眼柄视神经节发育特征的初步研究

应用组织切片技术于光镜下研究了中华绒螯蟹不同阶段的眼柄神经节的发育特征及其神经分泌细胞.根据细胞的大小、形态以及细胞质染色的深浅,将眼柄神经分泌细胞分为4 种类型;并讨论了这4种细胞在河蟹不同阶段的变化.     

诱导池养斑节对虾的性腺发育与产卵

室内条件下,采用切除、烫灼眼柄及蓝、绿色光源光照,可有效诱导池养斑节对虾的卵巢获得不同程度发育或成熟产卵,有效率分别为64.8％和15.5％,总有效率达80.3％。亲虾个体大小及水温与卵巢发育或产卵的关系密切。体重70克以上的亲虾卵巢易催熟,性腺发育成熟大多出现在水温较高的 5—9月份(平均水温 25.0—29.5℃),尤其产卵仅在这些月份发生。亲虾产卵量较少(每尾 3—11万个/次)。室内环境下亲虾无自然交配,卵子不能孵化,仅其中一次产卵中,进行了人工交配孵化出无节幼体。