锯缘青蟹精子发生的超微结构

采用透射电镜观察锯缘青蟹精子发生过程中超微结构的变化,结果表明：精原细胞椭圆形,染色质分布于核膜周围,胞质中具嵴少的线粒体,内质网小泡等。初级精母细胞染色质呈非浓缩状,胞质中具众 内质网小泡,特殊的膜系及晶格状结构。次级精母细胞核质间出现由内质小泡聚集成的腔。     

锯缘青蟹精子超微结构的研究

利用光镜和电镜观察了锯缘青蟹成熟精子的形态和超微结构。精子呈陀螺形，无鞭毛，在较宽的一端环生着１０余辐射臂。精子由球状的顶体、核杯以及核衍生的辐射臂三部分组成。顶体包括顶体管和顶体囊，后者包绕在顶体管的中央管周围，并可分为头帽带，内层和外层区。顶体被杯状的核包裹，仅头帽露于精子表面。成熟的精子中，位于核杯和顶体管之间的核膜出现局部断续或消失，中心粒和一些胞器出现的核杯腔中。     

锯缘青蟹窦腺显微和超微结构研究

借助光学和电子显微镜观察据缘青蟹（Ｓｃｙｌｌａ ｓｅｒｒａｔａ）窦腺的形态结构。窦腺位于眼柄视神经节内髓背侧近外髓处。窦腺呈羹状;腺体壁山神经分泌细胞的末梢和神经胶质细胞组成。神经末梢内充满了电子致密的神经分泌颗粒。根据颗粒的大小、形态及电子致密度等特征,可以区分出４种类型的神经末梢。一些末梢中的多形性颗粒可能是由Ⅱ型末梢中的颗粒转变而成的。一些现象表明,神经分泌物质可以通过胞吐作用或一种类似“顶浆分泌”的方式释放,从而说明神经激素的释放可能是多途径的．     

锯缘青蟹嗅觉器官的保护性形态特征

用光镜和扫描电镜对锯缘青蟹嗅觉器官保护性的形态学结构进行了研究。内鞭基部具一个半圆锥形凹面 ,它使内、外鞭间形成约 4 0°的基本夹角。化感刚毛与着生面呈 30°～ 5 0°角 ,其小于两鞭间 4 0°～ 90°的可变张角。这种空间关系能有效地避免内鞭折断化感刚毛的可能 ,因而内鞭在化感刚毛前方形成了天然保护屏障。化感刚毛良好的柔韧性、基部的念珠状结构以及中部分节等特征可能在避免自身折断或变形方面具有作用。另外 ,外鞭顶段迎水面的杆状刚毛和刺状刚毛、内鞭迎水面上以及底节远侧端的刺状刚毛所处的位置 ,均是化感刚毛的重要门户 ,因此推测这些触觉性的刚毛可能有利于化感刚毛避开来自上、下及前方的絮状污物     

锯缘青蟹精子顶体反应的研究

采用正交实验法研究了诱导锯缘青蟹精子产生顶体反应的最佳条件。结果表明：从纳精囊中获得的精子,用离子载体Ａ23187(64μg/ml）诱导,在ＣaCl2浓度为0.25％,pH为9.0的人工海水中４０分钟,可以得到最大的顶体反应率（82.5%）。在此基础上采用光镜和电镜观察顶体反应过程中显微和超微结构的变化。顶体反应过程可大致分为两个时相,第一时相为顶体囊外翻;第二时相为顶体管前伸。本文还对顶体反应的作用进行了初步探讨。     

锯缘青蟹卵黄发生期卵母细胞和卵泡细胞之间的结构变化

通过电镜研究了锯缘青蟹二次卵巢发育过程中卵黄发生期（分为初期和后期）卵母细胞表面的结构和胞质的变化。卵黄发生初期分为：内源性卵黄发生阶段和有卵泡细胞直接参与的外源性卵黄合成阶段,前者特征为：在卵母细胞中充满了内质网泡,在泡内有不同程度的卵黄物质合成,此时在卵母细胞的表面区域,可见很多卵泡细胞向卵母细胞表面迁移,并包围卵母细胞。后者其特征是在卵母细胞的表面,有大量的胞饮小泡出现在卵膜的内面,随着两细胞表面膜的逐步融合和胞饮作用加强最后形成链锁状结构,胞质中靠近卵质周围有卵黄体的积极合成和大更换 脂肪滴积累,在此阶段的后期,卵泡细胞质已基本吸收完毕,卵泡细胞膜和卵母细胞膜融合,某些界面已无膜结构。卵黄发生后期在亲蟹孵出幼体后的第11d至第27d基本结束,此期也主要以外源性卵黄发生为主,在卵母细胞的周围,卵泡细胞迅速扩大,其间分布着大量的大小不同的囊泡和线粒体,在接近卵母细胞表面,还常可见大量的脂肪滴存在。卵泡细胞与卵母细胞间其膜结构完全消失,从而可使滤泡大片细胞质直接融入卵母细胞中,以后随着卵黄发生的进一步发展,卵母细胞与卵泡细胞的交界面逐步形成一个网状的膜结构屏障,同时在卵巢中可见正在降解的卵母细胞,在卵黄发生近结束以后,在卵母细胞的表面,逐步形成两层卵膜,这时的卵母细胞质中几乎充满了卵黄体和脂肪滴。     

锯缘青蟹精巢发育的组织学观察

组织学观察表明,锯缘青蟹（Scylla serrata)精巢发育周期可以分为精原细胞期,精母细胞期,精子细胞期,精子期和休止期5个时期。在划分精巢发育期的基础上,结合生精小管直径的成熟节段比例这2个指标,可以较准确地反映锯缘青解精巢的发育状况。而成熟节段比例可以作为锯缘青蟹精巢发育的表征指标。     

孵育温度对锯缘青蟹幼体质量的影响

研究了锯缘青蟹抱卵蟹培育和胚胎发育及孵化温度对刚孵化第 1期状幼体 ( Z1)干重 ( DW)和比能值 ( EC,J/mg)以及对幼体发育和存活的影响 .研究结果表明 :胚胎发育随孵育温度的升高而加快 ,但孵育温度与刚孵化幼体的干重和能量 ( E,J/ind)没有明确的相关性 ;而抱卵蟹培育和胚胎发育期间孵育温度的日温差对刚孵化青蟹幼体的干重和能量有明显的影响 ,并对幼体的存活和进一步发育产生影响。当孵育温度日温差≥ 2℃时 ,胚胎发育不整齐 ,孵化不同步 ,死卵或孵出原状幼体的比例高 ;孵化出的第 1期状幼体一般都无法蜕皮进入第 2期。孵育温度日温差与刚孵化幼体的干重或能量的相关性不确定 ,但当孵育温度日温差≥ 2℃时 ,刚孵化的状幼体的个体干重和能量的乘积 ( DW× E) <0 .74 6的几率显著增加 ,幼体可养活的几率极小 ,( DW× E)可作为判断刚孵化的第 1期状幼体能否正常生长发育的指标     

汕头牛田洋沿海围垦区锯缘青蟹病害爆发的环境因素

锯缘青蟹(Scylla serrata)是汕头市的传统特色和优势养殖品种,也是拥有3万多亩海水养殖池塘的牛田洋围垦区的主养品种。近年来,每年9-11月份,牛田洋的青蟹病害严重,经济损失较大。为探讨青蟹发病与养殖环境的关系,于2007年4月至12月份对牛田洋养殖区的水体理化因子和生物因子进行连续监测研究,结果发现:各因子呈现出明显的季节性变化。在发病前的7-8月份,青蟹处于较高水温(≥28℃)和较低盐度(≤6)环境中。在发病期(9-11月份),各种环境因子恶化,其中铵态氮(NH4+-N)和亚硝态氮(NO2--N)在9月份达到峰值,分别为235.63μg·L-1和27.75μg·L-1;硝态氮(NO3--N)(10.85μg·L-1)、无机磷(PO34—P)(39μg·L-1)及生物因子(水体异养菌157.93×105cfu·L-1、弧菌116.75×103cfu·L-1,干重底泥异养菌157.93×105cfu·g-1、弧菌141.65×103cfu·g-1)在10月份达到峰值。结果说明:水体理化因子的恶化和条件致病微生物的大量增生是青蟹病害爆发的重要原因。     

锯缘青蟹主要过敏原的纯化与鉴定

以锯缘青蟹为研究对象,从免疫鉴定、分离纯化、抗体制备和免疫学分析等方面对其主要过敏原进行研究。首先利用过敏者血清的免疫印迹法,确定锯缘青蟹的主要过敏原为分子量约38kD的蛋白。然后通过制备丙酮粉、等电点沉淀、硫酸铵沉淀及加热处理对分子量为38kD的主要过敏蛋白进行了高度纯化。该蛋白的pI约为4.5,与虾的原肌球蛋白Pena1性质相近,证实了锯缘青蟹的主要过敏原为原肌球蛋白。通过免疫新西兰大白兔,制备了原肌球蛋白的抗血清,采用Protein A Sepharose亲和层析柱对动物抗体进行了纯化。该抗血清效价高,经4×105倍稀释后仍能与抗原进行反应。该抗体与甲壳类动物及软体动物的原肌球蛋白具有较强的免疫交叉反应,可用于食品过敏原检测。       

Histochemical characteristics of spermatophore layers of Scylla serrata (Forskal) (Decapoda: Portunidae)

The spermatophores of S. serrata are protected by an outer thick chitinous layer and an inner thin non-chitinous one. Both layers are rich in acid mucopolysaccharides containing sulphated (outer layer) and carboxylic groups (inner layer). The proteins of the two layers show much tryptophan, but lack tyrosyl, sulfhydryl and disulphide groups. No phenols or phenol oxidases could be detected histochemically in either layer, suggesting the absence of phenolic tanning in the spermatophore. The physical properties, as revealed from treatment with acids and alkali, indicate the resistant nature of the outer layer; the inner layer easily shrinks or disrupts under such treatment. The outer layer, though resistant, is readily permeable to low molecular weight dye substances employed in permeability experiments. The mechanism of sperm release is recorded and discussed. It is suggested that, in S. serrata, the dehiscence of spermatophore may be caused by imbibing of low molecular weight substances by the sperm mass substances of the spermatophore while the latter is inside the spermatheca.     

Identification of polymorphic microsatellite loci in the mud crab Scylla serrata (Brachyura: Portunidae)

Five microsatellite loci are identified and characterized from the genome of Scylla serrata, a widespread and commercially important species of coastal marine crab. The loci were detected by randomly screening for di‐ and tri‐nucleotide repeat units within a partial genomic library developed for the species. The five loci consist of dinucleotide repeats and are both co‐dominant and polymorphic within the species. A sample (N = 36) of S. serrata from one Australian population has an average observed heterozygosity of 0.875 and provides no evidence of either linkage among loci or significant deviation from random mating expectations across loci. PCR products for each of the five loci were also observed from a small sample of three other species within the Scylla genus. These markers may provide genetic information that will be useful for both aquaculture and studies of natural populations of the genus.     

WSSV对锯缘青蟹的致病性及血清酶指标影响

锯缘青蟹(Scylla serrata)俗称青蟹,是我国重要的海水养殖蟹类.近年来,浙江、福建、广东等青蟹主要养殖地区出现了严重的青蟹病害.对浙江省养殖青蟹的发病原因和流行病学调查发现,白斑综合征病毒(white spotsyndrome virus,WSSV)与青蟹发病存在较大相关性.为进一步研究WSSV对青蟹的致病性和发病机理,作者采用白斑综合征病毒的除菌过滤液,以1:10-1:10000稀释度注射感染青蟹,结果表明1:10、1:100感染组的青蟹死亡率达100%,1:1000感染组死亡率为66.7%,1:10000感染组死亡率为38.9%.根据攻毒悬液的病毒浓度计算出WSSV对青蟹的LD50为1.19×104拷贝/只(7.93×103拷贝/g组织);取WSSV感染青蟹血淋巴进行PCR检测,攻毒死亡青蟹的WSSV检出率为100%,表明WSSV对青蟹有很强的致病力.分析病毒感染濒死蟹的血清酚氧化酶(PO)、过氧化物酶(POD)、超氧化物歧化酶(SOD)、碱性磷酸酶(ALP)、谷丙转氨酶(GPT)、符草转氨酶(GOT)等主要酶指标,发现病毒感染青蟹的PO、POD和SOD活力明显低于对照组,而ALP、GPT和GOT的活力则明显高于对照组;用WSSV单克隆抗体对感染蟹进行免疫组化分析,发现WSSV主要侵染青蟹的鳃、甲壳下表皮、心脏、肠、胃等组织的上皮细胞,尤其以鳃上皮细胞损害最为严重.     

Cuticle Ultrastructure Changes in the Crab Scylla serrata Over the Molt Cycle

Morphological and chemical studies on the cuticle during the molt cycle of the crab Scylla serrata were performed in order to understand the layer formation. Cuticle ultrastructure was studied by scanning electron microscopy (SEM). Energy-dispersive, X-ray diffraction, and X-ray fluorescence analysis were used for identification of the elements and phases in the inner surface of the cuticle. In the first stage (A) of cuticle formation, a thin pellicle organized as an irregular fragmented structure is built. It is composed mainly of alpha-chitin/protein beta-keratin-like complexes where heterogeneous mineral nucleation occur. It is impregnated by ferric concretions, responsible for the brown colour of the carapace. At the beginning of the mineralization process, a spheroidal inorganic phase appears consisting of dicalcium phosphate dihydrate (DCPD) Ca/P=1.00, octacalcium phosphate (OCP) Ca/P=1.33 associated with hydromagnesite and bromapatite traces. During further cuticle development in the remaining A stage and in the beginning of the B stage, calcite and magnesian calcite are formed from the precursor calcium phosphate phase. The next development in the C stages is characterized by intense calcareous thickening consisting mainly of calcite and of magnesian calcite, which become the major mineral fraction of the cuticle. Organic-inorganic complex precipitations exhibit different aspects as spongiform, filamentary helicoidal, and concentric radial arrangements during C1, C2, and C3, respectively. During different stages of the cuticle formation in Scylla serrata, these mineral deposits may partially result from the balance among different organic contents, mainly between alpha-chitin and protein beta-keratin-like compounds. On the other hand, the calcium crystallization on apatite and calcite polymorphic structures may be influenced by variations of physico-chemical factors in the cuticle compartment. J. Exp. Zool. 293:414-426, 2002.     

DNA damage and cell necrosis induced by naphthalene due to the modulation of biotransformation enzymes in an estuarine crab Scylla serrata

The sublethal effect of naphthalene (2.5, 5, and 10 mg L(-1)) was studied in an estuarine crab Scylla serrata with reference to macromolecular changes. Biotransformation enzymes such as cytochrome P450, cytochrome b(5), NADPH cytochrome P450 reductase, aryl hydrocarbon hydroxylase, glutathione-S-transferase, and UDP-glucuronyl transferase were elevated in the hepatopancreas of naphthalene-exposed crabs in comparison with control. Remarkable amount of DNA damage and cell necrosis was observed in hepatopancreas, hemolymph, and ovary of the crabs exposed to naphthalene, when compared with control. For all the parameters studied, a concentration-dependent gradient of the changes was observed. The expression of DNA damage and cell necrosis suggests an increased production of oxidants during naphthalene metabolism.     

三疣梭子蟹光感受器的形态和超微结构

用电子显微镜观察了三疣梭子蟹（Portunus trituberulatus）的光感受器。扫描电镜观察结果显示三疣梭子蟹复眼为半球形。复眼表面积约为25．12mm^2,组成的小眼为长六边形,面积约为24μm^2。复眼除背面有一拇指状的区域无小眼外,其余部分都由小眼组成。透射电镜观察显示,11个小网膜细胞组成了复眼的感光系统,分成上下两部分。4个小网膜细胞位于晶锥的两侧,组成了感光部分的远端,位于晶锥之下,7个小网膜细胞组成感光系统的主体,上下部位有重叠。两部分的小网膜结构上基本相同,都含有线粒体、多囊体、内质网、色素颗粒等,但是上部的小网膜细胞没有扳膜体,而且胞质比较致密,膜下储泡囊的空腔较小,里面有膜状结构。三疣梭子蟹感光系统有二种类型的感光细胞,可能具有不同的功能。