共查询到18条相似文献，搜索用时 250 毫秒
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丝腺是利用桑叶中的蛋白质和氨基酸成分转化为丝物质的器官。丝腺位于消化管腹面两侧左右成对长管状腺体是屈曲的,稚蚕期位于消化管的腹面,自五龄期渐渐扩至消化管的两侧,背面压着消化管,为体内最大最长的器官,据有人调查五龄丝腺细胞最大的时期全长达300—330毫米,前部丝腺的闹度相当于蚁蚕的阔度40倍,长度的12倍,厚度11倍,中部丝腺为蚁蚕的阔度的109倍,长度52倍,厚度31倍,后部丝腺为蚁蚕阔度的132倍,长度的26倍,厚度的14倍。 相似文献
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一、已_2胚子的特点 1.蚕类胚子生理上的反转蚕类催青开始到蚁蚕孵化期间胚胎有一个反转运动,这个反转是指胚子由腹面向外侧(卵的表面),背面屈曲的状态,变为腹面向内侧屈曲,同时从囊的腹侧移向背侧的运动,这个时期叫反转期。反转不仅在形态 相似文献
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孙晓会 《畜牧兽医科技信息》2018,(4)
正球虫的功能性单位是孢子,一种能动的呈香蕉形或雪茄形的细胞,顶端尖后端圆。球虫靠孢子在宿主体内移动并侵入上皮细胞内,并且子孢子代表着球虫每个生活史的起点和终点。与生活史中特殊阶段的关系由前缀来表示。子孢子是在孢子化卵囊中出现的感染形态。大小配子体融合后形成卵囊,卵囊减数分裂形成子孢子。子孢子侵入宿主细胞后通过一种复分裂即裂殖生殖形成许多裂殖子,速殖子分裂快,慢殖子分裂慢,如此等等。 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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《广东蚕业》1993,(4)
著者等报告了从一种夜蛾(Spodoptera depravate Butler)的微孢子虫(Nosema sp.)在昆虫组织培养细胞内发育的过种中,当所谓成熟孢子形成之前形成极丝卷曲数少的异型孢子,此类孢子能自行发芽并在细胞内建立感染且能持续进行(Iwano & Ishihara,1989)。其后又报告了家蚕微粒子病病原(Nosema bombycis)在同一培养细胞内与Nosema sp.相同的也在形态(极丝卷曲数少)和形成期(感染后到出现的时间)有差异的两种孢子(Iwano & Ishihara,1991)。本研究确认感染家蚕幼虫的N.bombycis在寄主体内也和昆虫培养细胞内一样,形成异型的两种孢子,特别对短极丝型孢子的生物学及在养蚕方面的意义进行了考察。 相似文献
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微孢子虫侵染研究进展 总被引：4，自引：0，他引：4
微孢子虫种类繁多,侵染寄主过程十分复杂,pH值、离子种类及浓度、温度、射线等都能激活孢子发芽侵入寄主.近年来微孢子虫侵染机理研究已从激活因子推进到孢子生理生化的研究.研究表明:微孢子虫孢内糖类物质浓度的变化与孢子内压升高,诱发极丝的弹出密切相关;同时,微孢子虫孢子的表面蛋白、极膜和极管蛋白(PTP)在孢子侵染寄主过程中扮演着重要角色. 相似文献
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Thelohanellus kitauei Egusa et Nakajima, 1981, was described from common carp Cyprinus carpio L. in Japan. In China, a myxosporean infecting the intestinal tissue of the same host species was described as Thelohanellus xinyangensis Xie, Gong, Xiao, Guo, Li et Guo, 2000, despite many similarities to T. kitauei. To examine the potential conspecificity of these species, a morphological and molecular investigation of T. xinyangensis was conducted. Comparing myxospore morphology, the mean spore length and width of each species is not identical between species, but ranges of dimensions overlap. These data are more suggestive of intraspecific variation than distinct species. Comparison of relative ratios of spore length to polar capsule length and spore width to polar capsule width of T. xinyangensis and T. kitauei reveal no differences and scanning electron microscopy reveals a smooth spore surface of T. xinyangensis, which is consistent with that of T. kitauei. Most convincingly, DNA sequences of the small subunit ribosomal RNA (ssrRNA) gene of the two species were identical. From the morphological and molecular biological data, we propose T. xinyangensis from the intestine of common carp is not a distinct species and is synonymous with T. kitauei. 相似文献
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以鲤吉陶单极虫孢子的可溶性抗原 ,采用 B淋巴细胞杂交瘤融合技术制备了 4A8、6 B8、7B93株杂交瘤细胞 ,并用该抗原免疫新西兰白兔制备了高免血清。通过对虫体进行抗原检测、定位和 Western- blot试验 ,结果发现 :4A8、6 B8、7B9和多抗经间接 EL ISA可检出抗原的最低质量浓度分别为 0 .14、0 .2 0、0 .32和 0 .86 mg/ L;IFA定位显示 ,单、多抗检出的抗原都定位于虫壁 ,其中 4A8的抗原主要位于虫体后部 (胚核附近 ) ,6 B8和 7B9的抗原主要位于虫体前部 (极囊附近 )和极丝 ;Western- blot试验表明 ,4A8结合的抗原相对分子质量为 72 0 0 0 ,多抗结合的抗原相对分子质量分别为 5 80 0 0、70 0 0 0、880 0 0 ,3株单抗和多抗均为抗 T.kitauei的抗体 ,4A8具有明显的种、期特异性 ;自然感染该虫的鲤鱼血清中查不到循环抗体。 相似文献
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This paper describes the parasite Henneguya corruscans n. sp. which infects the gills of Pseudoplatystoma corruscans Spix and Agassiz, 1829 found in the Paraná River, Brazil. The parasites belong to the interlamellar-epithelial type as defined by Molnár (2002) [Molnár, K., 2002. Site preference of fish myxosporeans in the gills. Dis. Aquat. Org. 48, 197–207]. The spores examined had thin, smooth walls with symmetric valves; the total length of the spores was 27.6 (25–29) μm. The spore body was ellipsoidal in frontal view and biconvex in lateral view and they measured 14.3 (13–15) μm long by 5 μm wide and 4 μm in thickness. The polar capsules were small and elongated, equally sized, with a rounded posterior extremity and tapering anteriorly, and they corresponded more or less the half the length of the spore body; they were 6.8 (6–7) μm long by 2 μm wide, and the polar filament formed 5–6 coils obliquely to the axis of the polar capsule. The tail was 13.7 (12–15) μm long and bifurcated shortly after the end of the spore body. The importance of the infection for the farming of P. corruscans is discussed. 相似文献
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为更深入地了解猪链球菌病的病理学特征,本文运用病理解剖学和组织病理学的观察方法,对3头8月龄人工致死的猪链球菌病猪进行了病理学研究。结果表明:死猪耳廓、颈下、腹下和四肢末端皮肤可见紫红色出血斑点;全身多器官肿大、出血,脾脏出血点隆起,边缘"锯齿"样突起,并有出血梗死区,切面略突出;关节肿胀,切开后可见大量黄色渗出物,关节窝有骨骼样赘生物是本病的主要特征。组织学表现为脏器组织呈现不同程度的出血以及嗜中性粒细胞浸润,各脏器还出现特有的病变。 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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The development of the parotid gland was examined in 36 bovine embryos and foetuses with a crown-rump-length (CRL) from 28 up to 1000 mm by light, transmission electron microscopical and actin-immunohistochemical methods. The anlage of the parotid gland in an embryo with 28 mm CRL can be found at the lateral angle of the primitive oral cavity as a local thickening of the epithelium. During the second month, the differentiation of primary ducts and endbuds starts and a lumen develops in the primary ducts. At the end of the second month a lumen appears in the terminal endbuds. In the immature endpiece cells first secretory granules can be seen from a CRL of 240 mm. In the third month differentiation between intra- and inter-lobular ducts is possible. Immature myoepithelial cells present as a basal layer of flattened cells between the epithelial cells and the basement membrane at the end of the second month. During further development they increase in number, become more flattened and form long cellular processes. At the end of the fourth month isolated actin filament bundles are formed, which were also detected by an antibody against smooth muscle actin. The actin filaments condense continuously until they fill the cell processes completely at the end of foetal development. 相似文献