马杜霉素对不同虫株柔嫩艾美耳球虫超微结构的影响

鸡体内用5mg/kg马杜霉素作用于柔嫩艾美耳球虫（Eimeria tenella)敏感虫株和抗药虫株，比较裂殖生殖阶段超微结构的差异。敏感株型裂殖体体积变小，所生成裂殖子的数目变小，裂殖子膨胀，裂殖子间（带虫空泡内）微管膨胀，结构模糊，有髓鞘样结构出现；限制膜外突和细胞质分离形成空隙，膜结构模糊，有破损；细胞浆空泡化，出现附加体和髓鞘样结构；少数细胞核的外膜外突和内膜分离，有的部位的核膜模糊、破损。首次发现裂殖子顶体结构发生异常变化，棒状体消失，微线数目减少或者消失；线粒体表现为形态改变，嵴脱落，内部形成空泡、膜状结构和髓鞘样结构，线粒体的嵴与长辆平行排列，且贯穿线粒体。抗药虫株没有发现异常变化。推理抗生素类抗球虫药的作用机理为破坏虫体结构和抑制虫体的生理机能两个方面；球虫对该类药物产生抗药性的机制是基因突变和药物选择的结果。     

柔嫩艾美耳球虫裂殖生殖阶段超微结构的研究

利用透射电镜对柔嫩艾美耳球虫（Eimeria tenella)裂殖生殖阶段的超微结构进行了观察描述。其第二次裂殖生殖方式为外裂殖生殖，裂殖子侵入宿主细胞后，裂殖子逐渐变圆形成裂殖体，此过程中裂殖子的棒状体首先消失，引后锥体和极环消失、最后微浅、淀粉颗粒和折光体消失。裂殖体长大后，细胞膜下陷，将裂殖体分成几个部分，随后裂殖体进行核分裂成多核裂殖体，此后在靠近细胞核处细胞膜加厚外突，临近部位的细胞膜凹陷，同时近突起部位内膜复合体加厚形成极环，随着时间的推移逐渐形成幼稚裂殖子，幼稚裂殖子后部与残体相连，此过程中裂殖子的锥、极环、微线、棒状体、淀粉颗粒、折光体依次逐渐形成。裂殖子成熟的标志为从残体脱离，裂殖子的膜下微管24根纵向贯穿裂殖子直达顶端和极环相连，裂殖子内部由锥体、锥体前环1、锥体前环2、极环、微线、线粒体、折光体和3－多个棒状体等组成。     

菲莱氏温扬球虫裂体生殖的发育过程及超微结构

菲莱氏温扬球虫（ＷｅｎｙｏｎｅｌａｐｈｉｌｉｐｌｅｖｉｎｅｉＬｅｉｂｏｖｉｔｚ，１９６８）的裂体生殖过程是在具皱褶膜的纳虫空泡中进行的。发育早期的滋养体外被单层界膜，胞质中含一些退化的运动期虫体特有的细胞器（如微线体等），以及丰富的内质网、线粒体、高尔基体等。裂殖子以外出芽方式形成于裂殖体表面。裂殖子外被３层单位膜，中层和内层组成内膜复合体。裂殖子中部表膜上有１～２个微孔。类锥体由５～６圈微管组成，内有１对棒状体颈部，２根锥体内微管和若干微线体。类锥体前为Ｒ１、Ｒ２。棒状体起于顶孔，止于虫体中部，分细的颈部和膨大的体部，虫体前部有大量微线体。膜下微管为２２根。核位于虫体后部，每代成熟裂殖子均有数个致密体和大量支链淀粉粒。     

药物对柔嫩艾美尔球虫内生阶段超微结构影响的研究

本文对柔嫩艾美尔球虫(Eimeria tenella)在鸡体内正常发育的超微结构和分别用三种抗球虫药物处理情况下超微结构的变化进行了观察和比较研究,注意到125ppm尼卡巴嗪(Nicarbazin)能引起裂殖生殖阶段的滋养体或初生裂殖体及裂殖子的线粒体、内质网等膜结构系统和核的异常变化;168ppm磺胺喹恶啉(SQ)对滋养体、初生裂殖体及裂殖子、大配子和卵囊壁的形成均有影响,对裂殖生殖阶段的影响主要表现为核膜的增生复制等一系列核的异常变化;对配子生殖阶段的影响表现为Ⅰ型和Ⅱ型卵囊壁形成颗粒(WFB_1和WFB_2)的异常变化;80ppm盐霉素(Salinomycin)对上皮内淋巴细胞(IEL)中的子孢子及粘膜中成熟裂殖子的影响表现为表皮的分离或破裂及胞浆内微线粒(MN)和多糖颗粒(PG)等的轮廓模糊。由药物引起的其他一些超微结构的异常变化也作了观察和描述。     

黄艾美球虫侵犯宿主组织的超微研究

利用透射电镜和扫描电镜相结合的技术对黄艾美球虫（E.flavescens）人工感染后的子孢子移动过程及被虫体寄生的宿主细胞形态学变化和粘膜形态学变化进行了观察。子孢子在进入小肠腺上皮过程中需白细胞介导，在白细胞内可发育成球形的滋养体，观察到有两个子孢子侵入同一白细胞的现象，但分别存在于各自的带虫空泡中，黄艾美球虫引起的肠粘膜损伤主要发生于感染177小时之后，其损伤主要表现在绒毛大片脱落，结缔组织裸露，表面可见到大量破损的孔洞及大量肠杆菌，被虫体寄生的腺上皮细胞基部膨胀，微绒毛脱落，细胞核膨大并部分包被虫体，有些细胞核裂解为二。     

斯氏艾美耳球虫细胞化学的研究

本文用组织化学技术对斯氏艾美耳球虫内生阶段和子孢子的细胞化学进行了研究。结果发现,多糖存在于第二代裂殖体、大配子体、大配子、合子、未孢子化卵囊和子孢子内。脂肪存在于第二代A型裂殖体、大配子、合子、未孢子化卵囊及子孢子内。整个内生发育阶段的虫体和子孢子均含有蛋白质。两型裂殖体、大、小配子体、合子和子孢子内均有Feugan反应阳性的DNA存在,而RNA存在于整个内生阶段和子孢子中。内生阶段虫体和子孢子均有ACP和SDH,然而ALP只存在于内生阶段,子孢子缺乏。     

表达黄色荧光蛋白和乙胺嘧啶抗性基因的转基因柔嫩艾美耳球虫的发育和致病性分析

为了研究外源基因表达对转基因柔嫩艾美耳球虫(Eimeria tenella)生物学特性的影响,对转基因球虫(TE1)和BJ株(野生强毒)的发育和致病性进行比较分析.结果显示,相对于BJ株,转基因球虫TE1株繁殖力下降约4倍,低剂量感染时致病性下降明显,但是高剂量感染时依然保持较强的致病性.另外,在荧光显微镜下发现,TE1有滋养体、第一代裂殖体/裂殖子、第二代裂殖体/裂殖子和大小配子体等内生发育虫体.孢子化卵囊内4个孢子囊并非全部表达黄色荧光蛋白.这些结果说明黄色荧光蛋白和乙胺嘧啶抗性基因的表达在一定程度上降低了转基因柔嫩艾美耳球虫致病性和繁殖力.在柔嫩艾美耳球虫合子减数分裂过程中,存在同源或异源染色体重组现象.     

贝氏隐孢子虫在丝毛乌骨鸡体内发育的扫描电镜观察

使用扫描电镜观察了贝氏隐孢子虫(Cryptosporidium baileyi) 在丝毛乌骨鸡体内内生发育虫体的三维形态。大量球形虫体嵌于微绒毛丛中。滋养体呈球形,直径1.54～1.76 μm 。裂殖体呈桔瓣形或旋涡形排列,直径2.4～3.0 μm ,内含8 个香蕉形裂殖子,大小为4 μm ×0.65 μm 。成熟大配子体直径为3.5 μm 。带虫空泡内、外侧基部均可观察到梳状结构,根据带虫空泡的结构将其分为2 类,其中一类为裂殖子或小配子的带虫空泡,另一类为卵囊的带虫空泡。     

柔嫩艾美耳球虫马杜拉霉素抗药株与敏感株的mRNA差异显示

利用柔嫩艾美耳球虫马杜霉素敏感虫株裂殖子和抗药虫株裂殖子为材料,对马杜霉素敏感虫株和抗药虫株进行差异显示PCR,共回收34条电泳差异片段,反向Northern点杂交鉴定4个片段为真正差异片段,并对4个片段进行测序、B1ast同源性比较.来自于马杜霉素抗药虫株裂殖子的ACD3-2序列与柔嫩艾美耳球虫微线-5同源性99%,说明AcD3-2序列是该基因的部分序列,微线-5蛋白与虫体融解宿主细胞膜、入侵、运动和溢出有关,在第二代裂殖子时期,抗药性虫株该序列发生转录,而在敏感虫株中沉默;HCD1序列来自马杜霉素敏感虫株,与柔嫩艾美耳球虫表面抗原16和17序列同源性分别为83%和86%,说明与这2个基因同源.AGD5片段来自抗药虫株,HAD8-2序列来自敏感虫株,通过比较这2条序列可能为新序列.     

贝氏隐孢子虫内生发育虫体的扫描电镜观察

贝氏隐孢子虫内生发育各阶段虫体寄生于气管和法氏囊的微绒毛丛中 ,鸭对贝氏隐孢子虫的易感性低于鸡和丝毛乌骨鸡。滋养体呈球形 ,平均直径 1 3μm ;typeⅠ裂殖体 ,平均直径 2 4μm～ 3 0 μm ,内含 8个裂殖子 ,呈逆时针旋涡状或呈桔瓣状排列 ;typeⅡ裂殖体内含 4个裂殖子 ,两种类型裂殖体的裂殖子之间填充着颗粒状残体并包围着一个大的球形残体。成熟裂殖子逸出的方式分为 4种类型。裂殖子大小为 3 0× 0 6 μm ,呈香蕉形。大配子体呈球形直径 3 3μm～ 4 2 μm ,小配子体直径为 3μm～ 3 6 μm。小配子呈子弹状 ,大小为 1 2 μm× 0 3μm ,并观察到成熟小配子的释放方式。带虫空泡可分为无球形残体和有球形残体两类 ,根据观察结果推测带虫空泡基部的梳状结构不具备营养器官的功能 ,营养器官应为带虫空泡的底部     

马鹿冻精解冻后精子超微结构观察

实验利用透射电镜技术和扫描电镜技术对冷冻/解冻后的塔里木马鹿精子的超微结构进行了观察。结果表明:电镜下观察,塔里木马鹿精子头部呈扁平的卵圆形,长约5.95μm。颈部很短且不明显,长约0.45μm,宽为0.62μm。尾部中段横切面近圆形,直径约为0.58μm,轴丝为9×2+2型;线粒体鞘螺旋段为64～70转。尾部末段仅见质膜包围,9束微管和1对中央微管,形成9+2微管结构。冷冻/解冻后塔里木马鹿部分精子结构发生了变化,一些精子肿胀、质膜皱褶、扭曲,部分质膜损坏或溃散;顶体轻度肿胀,顶体外膜凸凹不平,形成突起。冷冻对头部破坏程度较小。     

Effect of bovine adenovirus 3 on mitochondria

Viruses alter the structure and the function of mitochondria for survival. Electron microscopy analysis of the cells infected with bovine adenovirus 3 revealed extensive damage to the inner mitochondrial membrane characterized by dissolution of the cristae and amorphous appearance of mitochondrial matrix with little or no damage to the outer mitochondrial membrane. There were fewer cristae with altered morphology. Potential patches of protein synthesis machinary around mitochondria could be observed at 12 hours post infection (hpi). At 24 hpi, the multi vascular bodies were evident throughout the infected cell. ATP production, mitochondrial Ca²⁺ and mitochondrial membrane potential (MMP) peaked at 18 hpi but decreased significantly at 24 hpi. This decrease coincided with the increased production of superoxide (SO) and reactive oxygen species (ROS), at 24 hpi indicating acute oxidative stress in the cells and suggesting a complete failure of the cellular homeostatic machinary. The results reveal an intericate relationship between Ca²⁺ homeostasis, the ATP generation ability of cells, SO and ROS production, and regulation of MMP following infection by bovine adenovirus 3.     

Secretion of virulence factors by Escherichia coli.

In order to interact with their host, pathogenic strains of E. coli need to secrete some virulence factors which can modify the metabolism of host cells, contributing to disease. Since E. coli is a Gram-negative bacteria, this secretion process involves the crossing of both the inner and the outer membranes. E. coli uses mainly four secretion mechanisms called type I, type II, type III and type IV secretion systems. In the type I secretion system, the secretion machinery is composed of three proteins forming a channel through the inner and outer membranes. It is a one-step mechanism. The secretion signal is present in the carboxyterminal region of the secreted protein but without proteolytic cleavage. In E. coli, the best studied type I secreted protein is haemolysin. In type II and type IV secretion systems, the crossing of the inner membrane involves the sec machinery with the cleavage of an aminoterminal signal sequence. The crossing of the outer membrane involves the formation of a pore either by other proteins (type II) or by the carboxyterminal region of the protein (type IV). The A-B toxins, such as heat labile enterotoxin, are secreted by the first mechanism and members of the IgA proteases are secreted by the second. The type III secretion system involves at least 20 proteins including cytoplasmic, inner membrane and outer membrane proteins. The originality of this system is the ability to inject secreted bacteria into the cytosol of the host cells. Such a system is found in attaching and effacing E. coli and in diffusely adhering E. coli.     

兔精液冷冻复温后超微结构变化和低渗膨胀实验

实验从精子超微结构的变化对冷冻解冻精子的损伤进行研究。结果表明冷冻复温后兔的一些精子不同程度出现了质膜膨胀、变薄、皱褶及损伤；顶体肿胀、顶体外膜、内膜囊泡化或不连续，及顶体完全脱落；部分精子中段质膜破损。线粒体裸露、断裂、电子密度降低或部分丢失；少数主段末段质膜破损，抽丝断裂、散开。实验验证HOST（hypoosmotic swelling test)适合于兔精子膜功能活性检测。     

The preparation of nucleated erythrocyte ghosts from avian erythrocytes

A method is described for the preparation of erythrocyte ghosts, which are haemoglobin‐depleted, from domestic fowl and turkey erythrocytes. These erythrocyte ghosts retain their ellipsoid shape and their nuclei, which are shown to possess the typical double nuclear membrane. In the cytoplasmic compartment of the ghosts, mitochondria have been clearly observed. There is little or no indication of endoplasmic reticulum. Filamentous structures have been seen adhering to the outer nuclear membrane, the mitochondria and the inner surface of the plasma membrane. These filaments may extend between the plasma membrane and the surfaces of the nucleus and mitochondria, thereby providing a form of structural anchorage for these organelles. It is a consistent observation that the nucleus of the intact erythrocyte and its ghost always occupies a central position, so some structure must be holding the nucleus otherwise one would expect to occasionally find it positioned off‐centre. Significantly, very few of the filament structures are observed at the extremities of the avian erythrocyte ghost, well away from the nucleus.     

伪狂犬病病毒Ra株体外感染ST细胞超微结构的研究

本研究以伪狂犬病病毒(pseudorabies virus, PRV)Ra株体外感染ST细胞为生物模型,通过透射电镜对PRV的增殖规律和致细胞病变的显微结构进行观察。结果显示,PRV能诱导ST细胞发生明显病变,细胞的病变程度与PRV感染时间密切相关。PRV Ra株感染ST细胞,病毒吸附于ST细胞表面,以膜融合内陷的方式进入细胞和细胞核内,在细胞核内复制,出现包涵体结构,以出芽方式离开细胞核,在高尔基体等细胞内膜结构处完成病毒粒子的囊膜化过程。感染前期,病毒通过膜融合方式被释放到细胞外,完成细胞间病毒的传播;感染后期,细胞溶解,大量释放病毒粒子。感染细胞超微结构的变化主要体现为:线粒体肿胀、数目减少,嵴面积减少,核内出现包涵体,细胞融合,细胞内空泡化严重,溶细胞现象。     

Development of the Retina in the Porcine Fetus A Light Microscopic Study

Morphogenesis of the porcine retina was studied using light microscopy from 4 weeks of gestation until birth (18 to 310 mm crown-rump length), and compared with the adult stage (6 months). Tissue samples were examined from the posterior and peripheral parts of the retina. At 18 mm the retina consists of an inner marginal layer and an outer layer of neuroblastic cells. At 18-40 mm the latter layer is divided into an inner and an outer neuroblastic layer by the transient layer of Chievitz. Subsequently, the development of the different retinal layers begins at the inner retinal border and moves progressively outwards; it also spreads from the posterior to the peripheral part of the neural retina. Many cells of the inner neuroblastic layer are prospective ganglionic cells which migrate inwards, thus forming the ganglion cell layer and the inner plexiform layer at 90 mm. At 120 mm, primitive horizontal cells appear within the outer neuroblastic layer. Separation of this layer into the inner nuclear, outer plexiform and outer nuclear layers is first evident at 180 mm. At this stage all retinal layers are present, except the layer of the photoreceptor cells which is not widespread until at 220 mm. The inner and outer segments of the photoreceptor cells lengthen considerably during the last month of gestation. During the late fetal stage the nerve fiber layer, the inner and outer plexiform layers and the layer of rods and cones all continue to increase in thickness. Concurrently, the ganglion cell layer and the inner and outer nuclear layers have reached their maximal thickness and become thinner. After the total thickness of the neural retina amounts to approximately 180 microns at two to three weeks before birth, it then thins to approximately 160 microns in the adult stage.     

副猪嗜血杆菌广东分离株外膜蛋白P5基因的克隆及蛋白结构预测

根据GenBank上发表的副猪嗜血杆菌(HPS)外膜蛋白基因的核苷酸序列设计并合成1对特异性引物,从广东省HPS分离株外膜蛋白P5基因中扩增出与预期设计的1116bp大小相符的片段,将扩增产物连接到pMD18-T载体上,进行序列测定和分析。结果表明,克隆出HPS广东分离株的目的基因,核苷酸长为1116bp,共编码371个氨基酸,与已发表的HPS(SH0165)外膜蛋白基因核苷酸序列同源性100%,氨基酸同源性100%。生物学预测分析结果显示,HPS外膜蛋白是一种混合型结构蛋白,含有α-螺旋、β-折叠、β-转角和无规则卷曲,其β-转角和无规则卷曲区域可能形成抗原表位;其N端含有1个信号肽,最佳切割位点在21～22个氨基酸;有15个抗原决定簇;无跨膜区;同源建模分析,未见相似三维结构。