氨氮对脊尾白虾幼体存活生长及体内RNA/DNA比值的影响

以脊尾白虾(Exopalaemon carinicauda)糠虾幼体为实验材料,用氯化铵模拟水体中氨氮进行毒性试验.结果表明,氨氮对糠虾幼体24、48、72和96 h的半致死浓度(LC50)分别为27.51、23.15、19.46和10.28 mg/L.糠虾幼体体内毒性蓄积程度随实验时间逐步增强.在6 d的糠虾幼体蜕壳...     

珠江口脊尾白虾的一些生物学观察

脊尾白虾Palaemon(Exopalaemon)carinicauda是珠江口咸淡水水域中重要的经济虾类,具有广温性、广盐性、广食性的特点,对酸碱度变化适应较强,耐低氧,繁殖力强,生长快,有的地方已作为一种养殖对象。鉴于此,笔者于1986—1988年在珠江口的福永、西乡、沙井对其生物学进行了一些观察。材料和方法每月(有时季度)在河口地带和池塘捞取30—50尾脊尾白虾,用解剖镜和显微镜进行形态和食性等观察,并计数卵数。为观察白虾对水环境因子的适应性,变化水温观察白虾对温度的适应能力,以比重计测海水比重再换算为盐度观测白虾对盐度的适应能力,并以比色法测…     

脊尾白虾肠道微生物菌群结构

【目的】研究海水池塘养殖条件下的脊尾白虾肠道微生物菌群组成及多样性。【方法】采用PCR-RFLP技术,以直接提取的脊尾白虾肠道细菌总DNA为模板进行16S rRNA 基因扩增,产物与T载体连接建立质粒文库,从RFLP建立的文库中筛选出不同细菌来源的克隆子,将测定的差异克隆子16S rRNA片段序列与GenBank数据库进行比对。【结果】从脊尾白虾肠道的菌群文库中共获得114个克隆子,Hae Ⅲ和Msp I双酶切得到11种差异克隆子;对差异克隆子测序后,其中8个差异序列与已知细菌具有较高的同源性,分别是假单胞菌属(Pseudomonas)、肠杆菌属(Enterobater)、冰冻小杆菌属(Frigoribacterium)、褐杆菌属(Phaeobacter)、弧菌属(Vibrio)、赤杆菌属(Erythrobacter)、气单胞菌属(Aeromonas)、葡萄球菌属(Staphylococcus)和其他未培养细菌。【结论】初步揭示了脊尾白虾肠道微生物菌群结构的组成,为开发脊尾白虾专用微生态制剂提供基础资料。     

浙江乐清湾脊尾白虾的繁殖和世代的初步研究

脊尾白虾分布很广,普见我国沿海,是我国特有的三种经济虾类之一,也是人工养殖对虾的主要竞争生物。 本文探讨了浙江乐清湾所产脊尾白虾的繁殖习性和种群世代;并提出了减少或控制人工养殖对虾塘内脊尾白虾的混生数量,从而提高人工养殖对虾产量以及发展脊尾白虾人工养殖的关键性措施。     

脊尾白虾生理性体温调节的初步观察

爬行类动物在升温和降温时不同的心率变化(心率滞后)是其进行生理性体温调节的重要机制.在与爬行类系统进化关系较远的甲壳类动物脊尾白虾 Exopalaemon carinicauda 的研究中发现,在升温和降温时也出现心率滞后现象,这对温度敏感的甲壳类动物的体温调节十分有利,同时对其体温调节的可能生理机制进行了讨论.     

盐度渐变与骤变对脊尾白虾渗透、代谢及免疫相关酶活力的影响

为探讨盐度变化对脊尾白虾(Exopalaemon carinicauda)渗透、代谢及免疫相关酶活力的影响,实验设置了盐度渐变和骤变两个实验。渐变实验,设置5、10、15、20、25、30、33(CK)、40和45共9个盐度梯度;骤变实验,盐度从33突变至0、5、15、25和45,检测血清ATP酶(包括Na+/K+-ATP酶和总ATP酶)、碱性磷酸酶(AKP)、酸性磷酸酶(ACP)及超氧化物歧化酶(SOD)活力。结果表明,渐变情况下,盐度为5时,ATP酶活力出现最高值,然后随着盐度的升高表现出先降低后升高的趋势。总ATP酶活力在盐度为15—30之间较稳定,并在此范围内达到最低值。AKP和ACP活力几乎不受盐度渐变的影响。SOD活力随盐度的升高,先上升后下降,并在盐度为33时达到最大值。骤变情况下,ATP酶活力随时间波动较大,AKP和SOD随时间波动较小,而ACP几乎不受影响。结果说明,盐度骤变对脊尾白虾酶活力的影响较盐度渐变明显,ATPase和SOD活力更易随盐度而变化,代谢酶(AKP、ACP)受盐度变化的影响较小,说明渗透调节和免疫相关酶活力对盐度变化反应敏感,养殖过程中应尽量保持盐度稳定。     

盐度对脊尾白虾亲虾抱卵及其子代生长发育的影响

选用室内人工培育的性腺已发育到Ⅱ期的脊尾白虾亲虾,经逐级淡化后,盐度稳定在2、5、10、15、20、25、30,研究了盐度对雌虾抱卵、胚胎发育及子代生长发育的影响.结果表明： 在试验盐度范围内脊尾白虾性腺均可发育成熟,但在盐度2时无法完成抱卵,最适抱卵盐度为10~20;在抱卵盐度范围内,胚胎均可正常发育,盐度对胚胎发育速率影响显著,15、20、25盐度下的孵化时间显著低于其他盐度组;盐度对脊尾白虾幼体后的变态和存活无显著影响,但对仔虾的个体干质量影响显著,15和20盐度下仔虾的干质量显著高于其他盐度组;盐度对20日龄脊尾白虾的生长影响显著,其特定生长率随着盐度升高而逐渐增大,在盐度20时达到最大,之后开始降低;鳃Na⁺-K⁺ ATPase的mRNA相对表达量在高盐或低盐时均较高,表达量最低时的理论盐度为17.5,可能为脊尾白虾的等渗点.研究表明,脊尾白虾亲虾可在较广盐度范围内繁殖,20日龄脊尾白虾在其理论等渗点附近具有较快的生长速度.
     

脊尾白虾组织蛋白酶L基因的克隆及其表达分析

根据本实验室构建的脊尾白虾(Exopalaemon carinicauda)血细胞全长cDNA文库获得的EST序列,利用RACE技术克隆获得脊尾白虾组织蛋白酶L基因的cDNA全长,命名为EcCatL基因.该序列全长1136 bp,包括5'非编码区24 bp,开放阅读框960 bp和3'非编码区152 bp,开放阅读框共编码319个氨基酸,预测相对分子量为35.30×103,理论等电点为5.27.同源性分析表明,脊尾白虾组织蛋白酶LEcCatL氨基酸序列与其它甲壳动物高度保守,与变色小长臂虾(Palaemonetes varians)及北极甜虾(Pandalus borealis) CatL的同源性分别为92％和76％.系统进化分析表明,EcCatL基因氨基酸序列与变色小长臂虾的CatL聚为一支.荧光定量PCR分析结果表明,EcCatL基因在血细胞、鳃、肝胰腺、肌肉、卵巢、肠、胃及眼柄中均有表达,其中肝胰腺中的相对表达量最高.感染鳗弧菌及WSSV后6h和12h,脊尾白虾血细胞和肝胰腺中EcCatL的表达量较对照组均极显著增加(P＜0.01),且具有明显的时间差异性,表明EcCatL基因在脊尾白虾免疫反应中具有重要作用.     

通径分析在脊尾白虾育种形态性状选择中的应用

选择胶州湾134只野生脊尾白虾（Exopalaemon carinicauda）,对其体长、全长、头胸甲长及体重等24项性状进行测量,采用相关分析和通径分析的方法,分析了形态性状对体重的影响效果,并构建形态性状与体重的多元回归方程.结果表明,各形态性状与体重的相关系数均达到了极显著水平（P<0.01）;全长、头胸甲宽、头胸甲高、第一腹长、第二腹高、第三腹宽对体重的通径系数达到显著水平（P<0.05）;所选形态性状与体重的复相关指数R²=0.954;多元回归分析建立了全长、头胸甲宽、头胸甲高、第一腹长、第二腹高、第三腹宽对体重的回归方程Y=-2.783+0.014X₁+0.130X4+0.095X₁₃+0.126X5+0.045X6+0.149X11.试验结果为脊尾白虾良种选育研究提供了理想的测度指标.     

食物条件对日本蟳幼体存活与变态的影响

This paper studied the effects of different kind and density of baits and different starvation duration on Charybdis japonica larvae. The results showed that the preferable baits of zoaea-1 were Chaetoceros sp. and Isochysisgalbana, and their proper feeding density were 20 × 10^4 cell· ml^-1. The preferable bait of the larvae after zoaea-1 was Artemia salina nauplius, and its proper feeding density for zoaea-2 and zoaea-3 was 2 - 3 ind· ml^-1. The point of no-return for zoaea-1 of Charybdisjapoptica was about 66 hours. 18 hours starvation did not affect the growth of the larvae, but their livability would be decreased, and their metamorphism would be suspended along with the starvation duration.     

孵化温度对黄喉拟水龟胚胎发育和幼体特征的影响

用3个恒定温度(24、26和28℃)孵化黄喉拟水龟南方种群卵,检测孵化温度对孵化期、孵化成功率和孵出幼体特征的影响。孵化温度显著影响孵化期和孵化成功率、以及幼体的性别、大小和早期生长。黄喉拟水龟幼体的性别取决于孵化温度(属TSDⅠa型),26℃和28℃孵出幼体偏雄性,30℃孵出幼体都是雌性。随着孵化温度的升高,孵化期呈非线性缩短,而孵化成功率略微增加。较高温度下孵出的幼体较大且具有较好的功能表现,但生长较慢。低温孵出幼体较小,但胚后生长速率较快。低温孵出幼体较小可能与胚胎发育期长、总代谢消耗大有关;而生长速率快则可能是因为低温产生的雄性幼体生长快于高温产生的雌性幼体。与已报道的黄喉拟水龟北方种群卵孵化结果相比较,26℃和28℃条件下南方种群卵的孵化期和产生1∶1性比的关键温度较大。这种地理上的变异可能反映不同种群对当地热环境适应性上的差异。     

The effect of temperature on the growth,development and survival of Macropetasma africanus (Balss) (Penaeoidea:Penaeidae) larvae reared in the laboratory

Macropetasma africanus (Balss) has been successfully spawned and its larvae reared under controlled laboratory conditions. The relationship between egg number (E) and female total length (L) was E = 18.59 L^2.11. An experiment was designed to test the effect of temperature on larval development, survival and growth. Temperature effected larval development time, from 13–15 days at 25°C, to 25 days at 15°C (nauplius 1 to post-larva). Mortality was low for the naupliar stages at 25, 22 and 18°C, while at 15°C only 52% of the larvae reached nauplius 6. Mortality was highest from nauplius 6 to protozoea 1 (17, 21, and 18% at 25, 22, and 18°C, respectively), but decreased considerably for all temperatures once the mysis stage was reached. Overall survival rates from nauplius 1 to post-larva decreased with decreasing temperature (65, 54, 48, and 39% at 25, 22, 18, and 15°C respectively). Temperature also significantly affected larval growth. At 25°C mean total length was significantly (P < 0.05) larger than at 15°C (protozoea 2 to post-larva), while from protozoea 3 to post-larva total length differences were significantly different (P < 0.05) between 18 and 25°C. M. africanus has a major spawning peak in summer, suggesting that there may be a selective advantage to reproducing during the warmer months.     

Effects of parasitism by Asobara tabida (Hymenoptera: Braconidae) on the development,survival and activity of Drosophila melanogaster larvae

The impact of parasitism by Asobara tabida on Drosophila melanogaster larval development, survival features and larval activity has been investigated using two strains of the parasitoid. The successful parasitism rate of the A1 strain was four times greater than that of the WOPV strain. Both strains induced equivalent mortality rates but hosts parasitized by A1 predominantly died as pupae. The time necessary for the host pupariation and emergence, and the larval weight at 72, 96 and 120 h post-parasitization were measured. Parasitized larvae exhibited longer periods of development and lower weights than controls, especially when parasitized by A1. These results suggest that hosts underwent physiological costs varying with respect to the outcome of the parasitic relationship. Of the parasitoid factors possibly responsible for these costs, we examined venoms for their impact on host mortality. Artificial injections of WOPV venoms induced higher mortality rates than did A1 venoms. Venoms were also found responsible for the induction of a transient paralysis, naturally occuring after parasitization. Again, the strongest effect was observed after parasitization by WOPV or injections of its venoms. This study gives new insights into the intriguing features of A. tabida and constitutes the first report of the paralysing properties of the venoms.     

温度对褐飞虱发育、存活和产卵影响的关系模型

设置系列恒温19、22、25、28、31、34℃,测定了温度对褐飞虱发育、存活和产卵的影响,建立了温度对褐飞虱生物学参数影响的关系模型。试验结果表明:(1)褐飞虱卵和若虫的发育历期在28℃下最短。除22℃以外,短翅型雌若虫的发育历期长于雄若虫的发育历期。(2)34℃下,褐飞虱卵未成功孵化,推测34℃是褐飞虱发育的限制性高温。不同温度下若虫的存活率为:25℃22℃28℃19℃31℃;低温主要导致低龄若虫死亡,而高温则主要导致高龄若虫死亡。(3)不同温度下产卵前期为19℃31℃22℃25℃28℃。产卵期22℃时最长。短翅型雌虫寿命随着温度降低而延长,产卵量在28℃时最大(256粒),19℃时最低(108粒)。(4)采用温度(x)与褐飞虱各生物学参数(y)间进行回归分析,获得一系列关系模型;其中,卵历期(y=0.079 x2-4.462 x+70.536),若虫历期(y=0.233 x2-12.886 x+189.878),产卵前期(y=0.068 x2-3.614 x+49.88)和短翅型雌成虫寿命(y=-0.622 x+35.03)与温度间具有显著的回归关系。     

Structure and development of the style base in Abildgaardia, Bulbostylis, and Fimbristylis (Cyperaceae,Cyperoideae, Abildgaardieae)

The Abildgaardieae tribe within the family Cyperaceae comprises six or seven genera, among which Abildgaardia, Bulbostylis and Fimbristylis pose a challenge regarding their morphological delimitation. Molecular phylogenetic analyses including species of Abildgaardieae are rare, but in most of those studies, Abildgaardia and Fimbristylis appear as more closely related to each other than to the Bulbostylis genus. Duration of the style base has been one of the most widely used characters for delimiting these three genera. The style base is a persistent structure in most species of Bulbostylis and deciduous in Abildgaardia and Fimbristylis. The reasons why the style base may persist or fall off have been scarcely discussed. The assumption that abscission layers are present in the style base of all three genera and the fact that tracheids have been observed in the style base of Bulbostylis suggest that this structure might have histological complexity. In view of this, a complete ontogenetic and anatomical study of the gynoecium has been carried out for all these three genera. It turned out that the style base is histologically simple in Abildgaardia, Bulbostylis and Fimbristylis and shows similar structure and development in all three genera. The fact that the style base has a shorter duration in Abildgaardia and Fimbristylis than in Bulbostylis might be related to the lower number of sclerotised cells that make up such structures in the mature fruit of the former two genera. Abscission of the style and style base may be the result of much simpler reasons than the differentiation of an abscission layer, resulting merely from mechanical shear force effects. Differences among genera have been observed in the shape of the style base and the development of the style. The histological simplicity of the style base is consistent with the homoplastic appearance of this structure in genera that are not closely related (e.g. Rhynchospora). Because of this, while the presence of the thickened style base seems to be a synapomorphy in species of Abildgaardieae, its persistence on or detachment from the fruit might have emerged repeatedly during this clade evolution and might not be a suitable character for genera delimitation.     

On the roles of Notch, Delta, kuzbanian, and inscuteable during the development of Drosophila embryonic neuroblast lineages

The generation of cellular diversity in the nervous system involves the mechanism of asymmetric cell division. Besides an array of molecules, including the Par protein cassette, a heterotrimeric G protein signalling complex, Inscuteable plays a major role in controlling asymmetric cell division, which ultimately leads to differential activation of the Notch signalling pathway and correct specification of the two daughter cells. In this context, Notch is required to be active in one sibling and inactive in the other. Here, we investigated the requirement of genes previously known to play key roles in sibling cell fate specification such as members of the Notch signalling pathway, e.g., Notch (N), Delta (Dl), and kuzbanian (kuz) and a crucial regulator of asymmetric cell division, inscuteable (insc) throughout lineage progression of 4 neuroblasts (NB1-1, MP2, NB4-2, and NB7-1). Notch-mediated cell fate specification defects were cell-autonomous and were observed in all neuroblast lineages even in cells born from late ganglion mother cells (GMC) within the lineages. We also show that Dl functions non-autonomously during NB lineage progression and clonal cells do not require Dl from within the clone. This suggests that within a NB lineage Dl is dispensable for sibling cell fate specification. Furthermore, we provide evidence that kuz is involved in sibling cell fate specification in the central nervous system. It is cell-autonomously required in the same postmitotic cells which also depend on Notch function. This indicates that KUZ is required to facilitate a functional Notch signal in the Notch-dependent cell for correct cell fate specification. Finally, we show that three neuroblast lineages (NB1-1, NB4-2, and NB7-1) require insc function for sibling cell fate specification in cells born from early GMCs whereas insc is not required in cells born from later GMCs of the same lineages. Thus, there is differential requirement for insc for cell fate specification depending on the stage of lineage progression of NBs.     

Evaporative water loss and energy metabolic in two small mammals,voles (Eothenomys miletus) and mice (Apodemus chevrieri), in Hengduan mountains region

Evaporative water loss (EWL) and energy metabolism were measured at different temperatures in Eothenomys miletus and Apodemus chevrieri in dry air. The thermal neutral zone (TNZ) of E. miletus was 22.5–30 °C and that of A. chevrieri was 20–27.5 °C. Mean body temperatures of the two species were 35.75±0.5 and 36.54±0.61 °C. Basal metabolic rates (BMR) were 1.92±0.17 and 2.7±0.5 ml O₂/g h, respectively. Average minimum thermal conductance (C_m) were 0.23±0.08 and 0.25±0.06 ml O₂/g h °C. EWL in E. miletus and A. chevrieri increased with the increase in temperature; the maximal EWL at 35 °C was 4.78±0.6 mg H₂O/g h in E. miletus, and 5.92±0.43 mg H₂O/g h in A. chevrieri. Percentage of evaporative heat loss to total heat production (EHL/HP) increased with the increase in temperature; the maximal EHL/HP was 22.45% at 30 °C in E. miletus, and in A. chevrieri it was 19.96% at 27.5 °C. The results may reflect features of small rodents in the Hengduan mountains region: both E. miletus and A. chevrieri have high levels of BMR and high levels of total thermal conductance, compared with the predicted values based on their body masses, while their body temperatures are relatively low. EWL plays an important role in temperature regulation.