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家蚕微孢子虫(Nosema bombycis)向家蚕BmN细胞接种与增殖的观察 总被引：9，自引：3，他引：6
利用DIPA活体荧光染色的方法对家蚕微孢子虫 (Nosemabombycis)的体外发芽、侵染、增殖的过程进行了观察。结果表明 :侵染过程从发芽开始持续到感染后 2 4h ,感染初期的芽体具有二核性 ,随后合二为一 ,感染后 2 4h进入裂殖体增殖阶段形成多核裂殖体 ,感染后 5 4h出现孢子母细胞、短极丝孢子及孢内发芽现象 ,感染后 6 0h出现二次感染体及趋于成熟的孢子 ,感染后 96h开始形成大量的成熟孢子、空孢壳及二次感染体的再分裂 ,此时在感染家蚕BmN细胞中 ,难于明确划分家蚕微孢子虫的各发育阶段。 相似文献
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从家蚕体内分离得到一株新的病原性微孢子虫,编号为GXM1。光学显微镜下观察GXM1微孢子虫为长卵圆形,大小(1.85±0.15)μm×(4.19±0.18)μm,在生活史的各发育阶段均为双核,以二分裂方式增殖,发育速度缓慢,发育周期约8～10 d。GXM1微孢子虫与家蚕微孢子虫(Nb)的抗血清产生阳性凝聚反应。利用透射电子显微镜观察到GXM1微孢子虫的超微结构具双核,极丝11～12圈,极丝倾斜角约45°。以上生物学性状显示GXM1微孢子虫具有微孢子虫属(Nosema)的基本分类特征。依据GXM1微孢子虫与其它昆虫微孢子虫的SSU rRNA基因序列构建的系统发育树,以及序列相似性和遗传距离分析,进一步证实GXM1微孢子虫属于Nosema属。GXM1微孢子虫对蚁蚕的半数感染浓度(IC50)为6.06×105mL-1,对家蚕的胚种传染率可达23.28%,是一株具有较强致病性和危害性的家蚕病原性微孢子虫。 相似文献
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在朱砂蛾幼虫(Tyria jacobaeae)63%的群体中发现了Nosema tyriae.sp.感染发生于肠壁、丝腺、脂肪体中,可以说感染面相当广但致病性很低。裂殖体增殖(merogony)和孢子生殖(sporogony)在偶核期(diplokaryotic stages)进行双分裂(bina-ry fission)方式繁殖。新鲜孢子延伸到前末端,大小为4.7×2.0um。将产孢体(sporont)表面和寄主细胞的细胞质联系在一起的20nm长的微管的超微结构引起了人们的兴趣,在孢子中,一种圆形极囊,包含了纵向紧密排列的细胞膜和横向松散排列的细胞膜,以及单列上有10.5-14圈极丝。N.tyriae和来源于家蚕(Bombyx mori)的桑蚕微孢子虫(Nosema bombycis)的16SrRNA基因只有六个核苷酸不同。N.tyriae对家蚕微孢子虫的单克隆抗体表现出中度的阳性反应。N.tyriae对家蚕具有感染性但毒性比N.bombycis要低。但是用N.bombycis的特异性引物扩增N.tyr-iae DNA却未得到扩增产物,两者的孢子形状也各不相同。另一种仅对其中一条家蚕幼虫具有轻微感染性的双核微孢子虫Nosema sp.具有更短的发育期,孢子大小为3.8×2.0um(固定)。超微结构上也极为不同,它的裂殖体(meront)和产孢体(sporont)中的细胞质囊泡均有大量致密的膜。从该微孢子虫感染的幼虫组织中可以观察到两种微管排列:一种具有约15圈极丝成不规则的成簇排列,或是以12圈极丝排成一列。由于该幼虫是和被N.tyriae感染的幼虫一起保存的,所以这两种孢子很可能是来自双重感染。 相似文献
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家蚕微孢子虫孢壁蛋白SWP25、SWP30、SWP32的表达谱分析 总被引：1，自引：1，他引：0
研究家蚕微孢子虫(Nosema bombycis,Nb)的孢壁蛋白对于揭示家蚕微孢子虫感染宿主的分子机制具有重要意义。对已完成精细定位的家蚕微孢子虫孢壁蛋白SWP25、SWP30、SWP32在家蚕中肠组织中的表达谱进行了分析。RT-PCR结果表明,SWP32在感染后24 h就可以检测到其转录本,SWP25、SWP30的转录本在感染后36 h可检测到,提示SWP32可能在孢子裂殖体阶段就需要发挥作用;3种孢壁蛋白在感染3 d后其转录本均达到较高水平,并在感染过程中持续保持,在感染后第10天仍能明显检出。3种孢壁蛋白在感染3 d后转录本量明显增加的现象与家蚕微孢子虫的生活史相符合,即:孢子母细胞在此阶段迅速增加并向成熟孢子转化,成熟孢子的孢壁在这一时期形成。3种孢壁蛋白的表达能在感染早期阶段的家蚕中肠组织中被检出,为进一步探讨3种蛋白的功能提供了线索,也为开发基于这3种蛋白的分子生物学及免疫学特异性的家蚕微粒子病早期诊断技术提供了理论依据。 相似文献
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2种野外昆虫来源微孢子虫的超微结构及生活史观察 总被引：1，自引：0，他引：1
将从湖南蚕区野外昆虫菜粉蝶(Pieris rapae)、桑尺蠖(Phthonandria atrilineata)分离到的2种微孢子虫感染家蚕,观察微孢子虫的寄生组织、生活史以及原代微孢子虫与在蚕体侵染繁殖的第1代微孢子虫的超微结构,作为探讨家蚕微粒子病发生与野外昆虫微孢子虫的关系的病原生物学依据之一。用Giemsa染色镜检观察的结果显示,2种来源的微孢子虫可在家蚕幼虫体内全面寄生,在中肠、丝腺、马氏管、脂肪体、生殖腺、肌肉组织、气管丛等组织中均能检出。电子显微镜观察2种来源的微孢子虫的超微结构,并与家蚕微孢子虫(Nosema bombycis,Nb)比较,结果显示在家蚕体内继代的源自菜粉蝶和桑尺蠖的微孢子虫的超微结构特征与Nb基本一致,孢子壁由3层组成,极体分为前后2部分,极丝同型,核成对出现,核形不规则,核膜双层,粗面内质网附含大量的核糖体,孢子后部有后极泡。2种来源的微孢子虫在家蚕体内的发育过程较为相似,所有时期的核都成对出现,以二分裂方式增殖,发育周期分别为72、96 h。 相似文献
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The development of Babesia occultans in the salivary glands of adult Hyalomma marginatum rufipes was studied with the electron microscope. Sporogony involved a process of multiple fission in which sporozoites formed from the periphery of a polymorphous sporont. Different stages of development were found concurrently in individual acini as well as within individual acinar cells. Mature sporozoites were found on Day 3 post-tick attachment and measures 3.0-3.5 X 1.5 micron. The apical complex consisted of a polar ring and 4-6 rhoptries. Micronemes were concentrated anteriorly and 1 or 2 spherical bodies were identified in each sporozoite. The general pattern of development was similar to that described in several other Babesia spp. but distinct morphologic differences were noted. 相似文献
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我国蝗虫微孢子虫超微结构与致病特性研究 总被引：2，自引：0，他引：2
从我国东亚飞蝗上分离出微孢子虫病原物圆形裂殖体(Meront),除单核、双核和四核外,还在本菌株观察到六核、八核等多核裂殖体。超微结构生活史观察,裂殖体细胞质膜很薄,与寄主细胞紧密相接,其细胞内含许多核糖体、囊泡和大量光滑内质网、双核、四核裂殖体,均呈双核相伴排列,以及正进行细胞质分裂的裂殖体和产孢体(Sporont);产孢体细胞壁加厚明显区别于裂殖体。整个生活史均为双核相伴排列。产孢体表面有多层电子致密物质呈短线条沉积。成熟孢子极膜层为指纹状片层结构,极丝圈18～20个。该病原物主要感染脂肪体和唾腺,并能引起寄生死亡,其死亡率有随接种剂量的增高而增大的趋势,而且3龄比4龄更敏感。接种后群体饲养比单头饲养死亡率高。病虫比健虫生育期延长2～3天,产卵能力下降,接种后24天病虫食物消耗比健虫减少35～75%。 相似文献
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中国广东家蚕微粒子孢子在Antheraea eucalypti细胞系的感染增殖 总被引：5，自引：0，他引：5
将中国广东的Ｎｏｓｅｍａ ｂｏｍｂｙｃｉｓ ＣＧＳ,用０２ｍｏｌ／ＬＫＯＨ 处理后,接种感染Ａ．ｅｕｃａｌｙｐｔｉ 细胞系。孢子的发芽率达８７％ ,在Ａ．ｅｕｃａｌｙｐｔｉ 细胞初期感染率为２７ ％ 。发育各阶段具２ 核,可观察到短极丝孢子和二次感染体形成,孢子芽母细胞按二分裂形成２ 个双核的孢子芽,具典型 Ｎｏｓｅｍａ 属特征。Ｎｏｓｅｍａｂｏｍｂｙｃｉｓ ＣＧＳ 生物学特性、血清学类型与日本Ｎｏｓｅｍａ ｂｏｍｂｙｃｉｓ ＮＩＳ００１ 大致相同,但孢子大小、裂殖体的形态、在Ａ．ｅｕｃａｌｙｐｔｉ 细胞寄生的细胞感染率、每个细胞的产孢数,２ 种微孢子虫却有差异。 相似文献
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Mori K Takahashi-Iwanaga H Iwanaga T 《The Japanese journal of veterinary research》2000,48(2-3):137-146
We found frequent and unique parasitism by an unidentified myxosporean in the kidney of the arctic lamprey, Lampetra japonica, living in Japan. Trophozoites (pseudoplasmodia with or without sporoblasts) existed predominantly in the lumina of proximal urinary tubules, but were rarely found in any other regions of the kidney. Since no mature spores were produced in the trophozoites, exact identification of the species was impossible. Two parasitic forms were recognized in proximal urinary tubules: one adhering to the epithelial cells of renal tubules, and the other free-floating in the lumina of tubules. Ultrastructurally, the attaching trophozoites developed microvilli-like projections towards the apical surface of epithelial cells and vigorously interdigitated with microvilli of the brush border. In contrast, the whole surface of the floating trophozoite was smooth without any cell projections. The developed projections in the former type of trophozoite may contribute to their firm attachment to the epithelial cells and/or to absorption of nutrients via the epithelial cells. Against the myxosporean infection, the lamprey as the host exhibited a local immune reaction by disposition of numerous lymphocytes and macrophages into the epithelium of urinary tubules. 相似文献
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Arroyo LG Weese JS Staempfli HR 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2004,18(5):734-738
Despite empirical clinical association of infection with Clostridium difficile with colitis in horses, a causal link has not been confirmed. The objective of this study was to develop a model of C. difficile-associated diarrhea in foals with normal transfer of passive immunity. Nine 1-day-old pony foals were inoculated intragastrically with spores or vegetative cells of C. difficile. Five foals were challenged with spores, with 2 receiving 10(5) colony-forming units (CFUs) and concurrently 3 receiving 10(7) CFUs once daily for 3 days. Clindamycin was administered orally to disrupt gastrointestinal flora. A further 4 foals were challenged by orogastric administration of 10(10) CFUs of vegetative cells once daily for 3 days or until diarrhea developed. This group did not receive clindamycin. Spore and vegetative cell preparations were negative for toxins of C. difficile and common enteropathogens. Clinical signs varied from mild abdominal discomfort and pasty feces to colic and watery diarrhea in 8 of 9 foals. Four of 5 foals challenged with spores developed mild diarrhea, whereas all foals challenged with vegetative cells developed moderate to severe diarrhea. C. difficile was isolated from feces of all foals between 24 and 72 hours after inoculation and toxins A or B or both were detected in the feces of all foals by an enzyme-linked immunosorbent assay. We concluded that spores and vegetative cells of C. difficile are capable of colonizing the gastrointestinal tract, producing toxins, and inducing clinical signs similar to those encountered in naturally occurring cases. This study fulfilled Koch's postulates for C. difficile-associated diarrhea in foals and provides a model for consistent reproduction of the disease for future studies. 相似文献
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Electron Microscopy of Intestinal Epithelial Cells of Piglets Infected with a Transmissible Gastroenteritis Virus 总被引：1，自引：1，他引：0 
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下载免费PDF全文 An electron microscopic study of intestinal epithelial cells of neonatal piglets infected with transmissible gastroenteritis (TGE) virus revealed a unique parasite-host cell interaction. Entry of the TGE virus into intestinal epithelial cells of newborn piglets is mediated through a network of cytoplasmic tubules of plasmalemma origin. the tubules, called microcanaliculi, are morphologically distinct from endoplasmic reticulum and Golgi. In uninfected animals similar tubules appear to be responsible for the indiscriminate uptake of large quantities of macromolecules from colostrum during the first few days of life.
Thin-section profiles of plasmalemma invaginations resembled tubules or canals and frequently contained viral particles. TGE viral particles developed and accumulated within cytoplasmic vacuoles. Initially the vacuoles were continuous with the microcanaliculi formed by deep plasmalemma invagination. Mature viral particles were 60 to 85 mu in diameter with an electron dense doughnut-shaped nucleoid surrounded by a trilaminar membrane which resembled the vacuolar wall. Abundant evidence of viral effects was observed in absorbtive epithelial cells of the jejunum and ileum but not of the duodenum.
The ability of absorbtive intestinal epithelial cells to form deep cytoplasmic tubular invaginations is temporally related to the pathogenesis of TGE and may explain in part why pigs usually are fatally affected by TGE only during the neonatal period.
相似文献17.
Membrane Alterations in Bull Spermatozoa after Freezing and Thawing and after In Vitro Fertilization
A. Krogen&#x;s K. Andersen Berg A. L. Hafne E. Engeland 《Acta veterinaria Scandinavica》1994,35(1):17
Membrane alterations in bull spermatozoa after freezing and thawing and after the process of in vitro capacitation and fertilization were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Even if the majority of the spermatozoa exhibited intact membranes after freezing and thawing (90%), one could distinguish between 3 types of membrane defects depending of the different structures involved. The first type showed loss of plasmalemma over the entire acrosome. In the second category the anterior part of the outer acrosomal membrane exhibited a pronounced extension, but was covered by a partly intact plasmalemma. The last category consisted of spermatozoa with extensive vesiculation and disruption of plasmalemma and the outer acrosomal membrane. This type of defect could not easily be distinguished from a true acrosome reaction. The cumulus cells showed an active phagocytosis of both intact and acrosome reacted spermatozoa. 相似文献
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伪狂犬病病毒弱毒株LY株的分离鉴定 总被引：3，自引：1，他引：2
从辽阳某猪场的10日龄仔猪中分离到1株病毒,经纯化后测得其毒价为107.29TCID50/mL.细胞中和试验表明,该病毒能被猪伪狂犬病病毒标准阳性血清所中和.电镜下可见到典型的疱疹病毒粒子,具有囊膜及外周纤突.所分离的病毒对氯仿、胰蛋白酶、乙醚敏感,在pH5.0～9.0下稳定,56℃ 30 min可以灭活.应用特异性引物,通过PCR能扩增出伪狂犬病病毒1 240 bp的gD基因.分离病毒对3日龄乳鼠有一定的致病力,但对家兔、3～5日龄仔猪及妊娠母猪都有很高的安全性.用不同剂量的病毒培养液肌肉注射于3～5日龄仔猪,14 d后用105.7TCID50伪狂犬病病毒强毒攻击,所有试验仔猪均可得到有效保护.用分离毒免疫母猪,其后代可获高滴度的母源抗体,15日龄的仔猪能抵抗105.7TCID50强毒的攻击.试验的结果初步说明,所分离的病毒为伪狂犬病病毒(命名为PRV LY株),并可能是一株弱毒株,而且具有很好的免疫保护作用. 相似文献