金乌贼(Sepia esculenta)精子超微结构和低温损伤电镜观察

利用扫描和透射电镜技术研究了金乌贼成熟精子的超微结构,以及超低温冷冻对精子超微结构和形态的影响。结果表明,金乌贼精子为鞭毛型精子,外部附有光滑的裙边状被膜,分为头部、中部和尾部三部分。头部由顶体和细胞核组成,顶体位于细胞核前端,呈"囊"状。细胞核为长纺锤状。中部是由线粒体和垂直的中心粒构成,线粒体大小不一,多层分布。尾部细长,轴丝为典型的"9+2"结构。经超低温冷冻的精子被膜上出现很多凹陷;头部顶体破裂,大量的内容物流出,细胞核膜分离;线粒体解离,嵴变形;尾部缠绕在一起,少数鞭毛出现脱落。     

红鳍东方鲀精子超低温保存前后的超微结构观察

应用透射电镜技术,研究超低温保存前后红鳍东方鲀(Takifugu rubripes)精子的超微结构。观察发现,受冷冻损伤精子的被膜膨胀、破裂、脱落;线粒体内嵴变形,结构模糊,甚至消失;鞭毛在基部或主段、末段断裂,或被膜膨胀脱落。结果表明,经超低温保存后,部分红鳍东方鲀精子由于膜结构及鞭毛轴丝损伤导致精子活力下降。     

点带石斑鱼的精子活力及超低温冷冻前后精子超微结构的比较

研究了盐度、pH对点带石斑鱼(Epinephelus malabaricus)精子活力的影响;同时对超低温冷冻前后点带石斑鱼精子的超微结构进行了比较观察。研究结果表明:(1)该鱼精子活力的适宜盐度范围为15-35,盐度为15时,精子寿命最长为26 min;最适pH值范围为6.5-8.0,当pH值为7.5时,精子的寿命最长为4 min;(2)超低温冷冻保存前,正常的点带石斑鱼精子由头部、中段和尾部3部分组成,精子头部呈球圆形或近圆形,直径约1.8 m;中段不明显,可见线粒体;鞭毛细长,约15 m,尾部主要结构是轴丝,为典型"9+2"微管结构;(3)超低温冷冻保存后,点带石斑鱼精子的形态结构损伤明显,主要表现为质膜褶皱、破裂,细胞质外漏,线粒体膨胀破损,脱落和鞭毛断裂等特征。     

日本蟳精子结构及环境因子对精子存活率的影响

以光镜和电镜观察了日本蟳精子的形态结构,对雄体贮精囊和雌体纳精囊中的精子结构进行了比较,并研究了pH,盐度对日本蟳精子存活率的影响规律,结果表明:日本蟳精子为非鞭毛型,主要由顶体、核杯、膜复合体和辐射臂等组成,其中顶体呈球形或近球形,可分成头帽、顶体管和顶体囊三部分。核杯包裹整个顶体外围,染色质呈细丝状或颗粒状。辐射臂向精子四周发出,内含核质,没有运动能力。雄体贮精囊中的精子包裹在椭球形精荚中,而雌体纳精囊中的精子呈弥散状,精子顶体管中有囊泡状结构、中心体位置前移、胞质透明区扩大,而且有些精子已崩解。精巢表面pH为6.5±0.2,精液pH为7.0±0.2,精子密度平均为(3.47×10⁹±0.42×10⁹)个/cm³。精子的适宜pH为7~9,最适pH为8;适宜盐度为20~30,最适盐度为25。     

日本蟳精子结构及环境因子对精子存活率的影响

以光镜和电镜观察了日本蟳精子的形态结构,对雄体贮精囊和雌体纳精囊中的精子结构进行了比较,并研究了pH,盐度对日本蟳精子存活率的影响规律,结果表明:日本蟳精子为非鞭毛型,主要由顶体、核杯、膜复合体和辐射臂等组成,其中顶体呈球形或近球形,可分成头帽、顶体管和顶体囊三部分。核杯包裹整个顶体外围,染色质呈细丝状或颗粒状。辐射臂向精子四周发出,内含核质,没有运动能力。雄体贮精囊中的精子包裹在椭球形精荚中,而雌体纳精囊中的精子呈弥散状,精子顶体管中有囊泡状结构、中心体位置前移、胞质透明区扩大,而且有些精子已崩解。精巢表面pH为6.5±0.2,精液pH为7.0±0.2,精子密度平均为(3.47×109±0.42×109)个/cm3。精子的适宜pH为7～9,最适pH为8;适宜盐度为20～30,最适盐度为25。     

入卵过程中太平洋牡蛎精子超微结构的变化

本文研究了精子入卵过程中太平洋牡蛎精子超微结构的变化规律。研究表明 ,精子入卵过程分为 4个时期 :顶体反应期、穿卵前期、穿卵期和融合期。顶体反应期 ,精子顶体物质释放 ,顶体致密部分向外延伸 ,形成 1层保护膜 ,亚顶体腔开始向顶端突起 ;穿卵前期 ,亚顶体腔前突形成顶体锥 ,并向卵膜释放亚顶体物质 ,精子外膜后移 ;穿卵期 ,精子核及线粒体进入卵膜形成的受精锥 ,线粒体数量减少 ,顶体突消失 ,精子外膜和尾部脱落 ;融合期 ,精子核进入卵内与质膜融合 ,核解体。     

文蛤(Meretrix meretrix)精子的超微结构及精子入卵过程的电镜观察

利用透射电镜和扫描电镜对文蛤精子的超微结构及精子入卵过程进行了详细观察。结果显示,文蛤精子为典型的原生型,由头部、中段和尾部三部分组成,全长45—50μm。头部呈狭茧形,长约3.0μm,由顶体和细胞核组成,顶体呈倒"V"字形,前端有短柱状的凸起;细胞核为稍弯曲的圆柱形,内含高度浓缩的染色质,无核前窝,有核后窝。中段较短,仅0.6—0.7μm,由线粒体围绕中心粒复合体构成,5个圆球形的线粒体呈单层梅花状排列,内部为双层膜折叠成的片层状结构;中心粒复合体由近端中心粒和远端中心粒组成,而远端中心粒延伸出尾鞭的轴丝。尾部为细丝状鞭毛,长约42—45μm,内部的轴丝呈典型的"9+2"结构,外周有波浪状质膜包被。用扫描电镜观察了文蛤精子的入卵过程,大致将其分为顶体反应期、穿卵期和卵膜修复期。受精后2min,精子发生顶体反应,顶体泡破裂释放溶解酶使卵膜变得疏松,亚顶体腔中伸出的顶体丝先穿透卵膜;受精后4—6min,在精、卵的共同作用下,精子头部和中段逐渐穿过卵膜进入卵内,在卵膜上形成一个直径约1.5μm的孔道,而精子尾部则留于卵外;受精后8—10min,精子尾部脱落,受精形成的孔道被卵膜的微绒毛修复。另外对多种双壳贝类精子超微结构和线粒体入卵等问题进行了探讨。     

体内受精许氏平鲉(Sebastes schlegelii)和体外受精大菱鲆(Scophthalmus maximus)精子结构及生理特性比较

为了解硬骨鱼许氏平鲉精子体内受精以及精子在雌性体内保持长期存活的特性,本研究应用扫描电镜与透射电镜对体内受精卵胎生硬骨鱼许氏平鲉与体外受精卵生大菱鲆的精子进行超微结构观察,并使用计算机精子分析系统比较精子激活后运动参数差异。结果显示,这两种鱼的精子均由头部,中段和尾部构成,无顶体,尾部轴丝为“9+2”微管结构。许氏平鲉精子特点：头部呈短棒状,细胞核呈长锥状;中段不对称,约30—40个线粒体呈垛叠状紧密排列在中段;轴丝质膜延伸形成的侧鳍较为发达。大菱鲆精子特点：头部呈椭圆形,头部和鞭毛结构松散,含有大量囊泡状结构;精子中段较短,向外突出的线粒体包裹鞭毛形成“半袖套”结构且尾部鞭毛侧鳍不发达。许氏平鲉精子密度和体外激活寿命均显著高于大菱鲆精子,而激活后精子的平均曲线速度（VCL）、平均直线运动速度（VSL）、平均路径速度（VAP）显著低于大菱鲆精子。研究表明,上述精子结构差异主要表现在精子头部与中段：体内受精硬骨鱼精子大多具有细长的头部,发达的中段,线粒体数量较多;体外受精硬骨鱼具有圆形或椭圆形的头部,中部不明显,线粒体较少。     

我国海域耳鲍(Haliotis asinisne)精子发生的超微结构研究

应用透射电子显微镜技术研究了我国海域耳鲍精子发生的全过程。结果表明,耳鲍精原细胞呈近椭圆形,染色质分布较均匀,线粒体较少;初级精母细胞较大,染色质凝聚成小块状,线粒体增多;次级精母细胞较初级精母细胞小,线粒体较多,部分线粒体发生融合,呈扁囊状。分化早期精细胞染色质凝聚成团块状,多数贴附于核膜内面,胞质中出现前顶体颗粒。分化中期精细胞染色质继续凝聚成较大的团块,线粒体在核的一端融合,形成数量少、体积大的线粒体,前顶体颗粒形成圆形外膜明显的前顶体。分化后期精核由近圆形变成长桶状,核内染色质凝聚并均质化,前顶体泡化发育成顶体,鞭毛形成,精细胞分化成精子。成熟精子为鞭毛型精子,由头部、中段和尾部(鞭毛)3部分组成。     

皱纹盘鲍(Haliotis discus hannai)精子的超微结构

皱纹盘鲍（Ｈａｌｉｏｔｉｓｄｉｓｃｕｓｈａｎｎａｉ）的精子属于“原始型”,由顶体（２．２μｍ×１．０μｍ）、细胞核（３．１μｍ×０．８３μｍ）、中段（０．７４μｍ×１．４μｍ）和鞭毛（５２μｍ×０．２２μｍ）组成。顶体弹头状,由两部分组成：（１）顶体的前端是一呈卵形的高电子密度的部分;（２）顶体的后端为一呈翼状的低电子密度的部分。细胞核呈长柱状。在顶体凹陷和细胞核凹陷之间为顶体下腔,内有微丝束结构。中段包括５或６个线粒体,一对中心粒及一些泡状结构。鞭毛为典型的“９＋２”结构。     

大黄鱼(Pseudosciaena crocea)精子冷冻前后的活力及超微结构变化

采用两步降温法超低温冷冻保存大黄鱼精子,并用透射电镜技术研究了精子的超微结构损伤.结果表明,大黄鱼冻精的激活率、运动时间及寿命与鲜精相比无显著差异.鲜精中28.5％的精子形态结构异常,冻精中37％的精子形态结构异常.形态结构正常的精子表现为质膜与核膜结构完整、无膨胀现象,袖套、轴丝及中心粒结构正常,线粒体形态完整、嵴较发达;形态结构异常的精子表现为质膜破裂、脱落,质膜膨胀,核膜破裂、脱落,核局部受损伤,线粒体膨胀、嵴退化或消失,线粒体移位或脱落.结果显示,以Cortland溶液为稀释液,10％ DMSO为抗冻剂,对大黄鱼精子具有较好的抗冻保护作用.     

A Finite Element Method for Cracked Components of Structures

1 .IntroductionOffshoreplatformsarelargescalesteelorconcretestructures.Theyexperiencevariouskindsofdamagessuchasdents ,corrosionpits ,cracks ,deformation ,etc .,afteryearsofenvironmentalimpactofwinds ,waves ,currents ,soilreactions ,earthquakesandice (DuanandLiu ,1 995) .Thesafetyofthestructureshasalwaysbeenthemostimportantissueconcerned ,anditdependsontheassessmentoftheintegrityofthestructures,orspecificallyontheassessmentofthedamagesinthestructures .Riclesetal.( 1 994)experimentallyinvestig…     

斑节对虾 弧菌病的病理学研究

对患有典型弧菌病症状的养殖斑节对虾进行了病理学研究，取病虾血淋巴制作血涂片，并取鳃、肝胰腺、肌肉等组织作组织病理和超微病理观察，同时取肌注感染后的患病对虾测定血淋巴中超氧化物歧化酶（SOD）的活力，结果显示，患病对虾的血细胞数目急剧减少，胞质浓染，透明细胞很难找到，血细胞形态多样，有的伸出伪足或形成异样突起，患病对虾锶、肝胰腺、心脏、肌肉以及胃肠等组织内均出现程度不同的炎症反应，以肝胰腺最为严重，组织中充满大量的浓染血细胞，细胞肿胀，细胞核核质边聚，线粒体肿胀，变性、严重时整个细胞呈溶解状态，此外，在鳃和肝胰腺组织中还发现溶酶体增多的现象，肌注感染2h后，感染对虾的SOD活力即开始显著下降，之后缓慢回升，至48h恢复大部分活力。     

In vitro acute cytotoxicity of the neonicotinoid insecticide acetamiprid to FG cells, the gill cell line of flounder Paralichthy olivaceus

1 IntroductionAcetamiprid (( E)-N1-[( 6-chlor-3-pyridyl )methyl]-N2-cyano-N1-methylacetamidine), a cyano-substituted neonicotinoid compound ( Kagabu,1999), is a relatively newclass of insectide, exhibi-ting a broad insecticidal spectrum ( Matsunaka,2000; …     

In vitro acute cytotoxicity of the neonicotinoid insecticide acetamiprid to FG cells, the gill cell line of flounder Paralichthy olivaceus

The in vitro acute cytotoxicity of the neonicotinoid insecticide acetamiprid to FG cell line, derived from the gill of flounder Paralichthys olizaceus, was tested by the three widely used endpoint bioassays-neutral red （NR） assay, tetrazolium （MTT） assay and cell protein assay. It was found that acetamiprid was increasingly toxic to FG cells at concentrations of 1 μg/cm^3 or above, and the inhibitory concentration 50% values for NR, MTF, and cell protein assays were 38.38, 36.27 and 32.03 μg/cm^3, respectively. This appeared to be the first report on the in vitro cytotoxicity of acetamiprid to non-mammalian vertebrate cells. Ultrastructural examination revealed that for the cells exposed to 60 μg/cm^3 acetamiprid for 48 h, their mitochondria were severely damaged with the cristae swelled up or disrupted, while their nuclei and rough endoplasmic reticlum （RER） appeared to be still normal. This suggests that mitochondria are possibly the primary target of acetamiprid.     

Stress Variation Model of Bond Stress-Slip Relationship Between Steel Bar and Concrete

Based on the experimental data, a stress variation model of the bond stress-slip relationship between steel bar and concrete is established. The characteristic of the model is that the boundary conditions are satisfied very well; the effects of the material properties, the concrete cover, the crack spacing and the distance from the cracked cross section are considered. Good agreement between measured and calculated bond stress-slip relationship is found. This model is useful for the study of the stiffness, deformation and crack width of reinforced concrete members, and for the nonlinear analysis of reinforced concrete structures by the finite element method.     

极端循环载荷下船体裂纹箱型梁的极限强度

旨在了解箱型梁在极端循环载荷下的极限强度特性。利用非线性有限元方法来研究裂纹箱型梁的极限弯矩,分析了5种裂纹模型,探讨了裂纹类型、裂纹位置和裂纹长度的影响。考虑了两种载荷形式应用生死单元法对双向循环弯曲下裂纹扩展进行了模拟;并将由循环载荷引起的累积塑性损伤和疲劳裂纹损伤均考虑在内。无论单向循环还是双向循环,单裂纹模型的极限弯矩均小于双裂纹模型的极限弯矩;单边裂纹是最危险的裂纹类型。进一步分析了极端循环载荷下裂纹箱型梁的极限强度折减机理,得出了极限强度折减归因于这两种损伤的耦合作用的结论,并通过其他箱型梁验证了其适用性。     

Effect of parental exposure to trenbolone and the brominated flame retardant BDE-47 on fertility in rainbow trout (Oncorhynchus mykiss)

We exposed sexually maturing male rainbow trout (Oncorhynchus mykiss) to BDE-47 (a polybrominated diphenyl ether) and female rainbow trout to trenbolone (an anabolic steroid). Male trout were orally exposed for 17 days to 55 microg/kg/day BDE-47 and female trout continuously exposed for 60-77 days to a measured trenbolone water concentration of 35 ng/L. After the exposure, eggs and semen were collected and in vitro fertilization trials performed using a sperm:egg ratio of 300,000:1. In the BDE-47 study, eggs from control females were fertilized with semen from exposed males, while in the trenbolone study, eggs from exposed females were fertilized with semen from control males. All treatments were evaluated at two-three early developmental time-points representing first cleavage (0.5 day), embryonic keel (9 days), and eyed stages (19 days), respectively. The results indicated that BDE-47 exposure did not alter fertility as embryonic survival was similar between control and exposed groups. Trenbolone exposure also did not alter embryo survival. However, in the embryos fertilized with eggs from trenbolone exposed females, a noticeable delay in developmental progress was observed. On day 19 when eye development is normally complete, the majority of the embryos either lacked eyes or displayed under-developed eyes, in contrast to control embryos. This finding suggests steroidal androgen exposure in sexually maturing female rainbow trout can impact developmental timing of F1 offspring.     

氯盐干湿环境下受弯横向裂缝对钢筋混凝土耐久性影响

为了研究持续开裂状态下横向裂缝对钢筋混凝土结构耐久性的影响特性,开展了8根受弯开裂钢筋混凝土梁构件的盐溶液干湿循环试验;借助无损检测技术和破损实测方法,分别对氯离子侵入量、钢筋半电池电位、腐蚀电流密度以及平均锈蚀率等进行了对比分析。研究结果表明,裂缝的存在将提高混凝土的渗透性,裂缝处及周围混凝土内的氯离子含量明显增大;对于一定裂缝分布状况的钢筋混凝土试验梁,内部钢筋的腐蚀电位、腐蚀电流密度以及平均锈蚀率均高于裂缝自愈及无裂缝的试验梁,并受到保护层厚度与裂缝开展状态的影响,其影响规律可用单位长度内的平均裂缝宽度与保护层厚度的比值wm/c来进行综合评价。综合试验结果,初步建议海洋干湿侵蚀环境下钢筋混凝土构件的最大裂缝宽度wmax宜小于0.003 3 c,相关结论可为海洋混凝土结构的耐久性设计提供参考。     

Cryopreservation of amphioxus (Branchiostoma belcheri) spermatozoa

Amphioxus, Branchiostoma belcheri, a closest relative of vertebrates, is at a high risk of extinction due to a combination of low effective population size, altered native habitats and environmental pollution, yet little is known about cryopreservation of its gametes. This study deals with the cryopreservation of amphioxus semen. The main findings are that (1) the extender of Yao et al. is the best one among the four extenders examined; (2) the appropriate ratio of semen to extender of Yao et al. plus cryoprotectant is from 1:5 to 1:7; (3) dimethyl sulfoxide (DMSO) and methanol are the better cryoprotectants than glycerol, with DMSO giving the best results; (4) the eggs fertilized with post-thaw spermatozoa are capable of developing to at least hatching stage, and the highest hatching rate is (12.4±3.0)%. This is the first report on freezing and thawing of amphioxus spermatozoa, providing a simple and practical protocol for cryopreservation of amphioxus spermatozoa and laying a foundation for safeguarding this endangered species.