共查询到20条相似文献，搜索用时 46 毫秒
1.
迄今描述的艾美耳科和住肉孢子虫科球虫的裂殖生殖为单态，作者发现斯氏艾美耳球虫的裂殖生殖具多态性，其方式有：子孢子型裂殖体以内单多生殖方式产生下代裂殖子；双或多核的裂殖子型裂殖体或以内二多生殖方式或以外单多生殖方式产生下代裂殖子；单核裂殖子型裂殖体以外多生生列殖方式下代裂殖子；经典型裂殖体以内单多和外单多混生方式产生下代裂殖子。这种裂殖体以多态的方式产生下代裂殖子的现象称为裂殖生殖的多态现象。依据前 相似文献
2.
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。 相似文献
3.
1球虫病多发的原因
1.1温度、湿度合适
鸡感染球虫后，球虫在肉鸡消化道内经过一段时间的裂殖生殖，所产生的裂殖子进行配子生殖，最后形成卵囊，随粪便排出体外。新鲜排出的球虫卵囊无感染性，但在一定的条件下（最适温度为22～30℃；湿度20％～30％；充足氧气等）完成孢子生殖，就形成了具有感染力的孢子化卵囊。 相似文献
4.
1球虫病多发的原因
1．1温度、湿度合适
鸡感染球虫后，球虫在肉鸡消化道内经过一段时间的多次裂殖生殖，所产生的裂殖子进行配子生殖，最后形成卵囊，随粪便排出体外。球虫卵囊本无感染性，但在一定的条件下（温度8℃～35℃，最适为22℃～30℃；湿度60％～75％；充足氧气等）完成孢子生殖，就形成了具有感染力的孢子化卵囊。这种卵囊一旦被鸡大量食入，就会造成球虫病发作。而夏秋季节，温度、湿度合适，正有利于球虫的繁殖。所以，夏秋季是肉鸡球虫的多发季节。 相似文献
5.
本文评价了柔嫩艾美尔球虫第二代裂殖子的免疫原性。试验采用弗氏完全佐剂乳化的裂殖子抗原及从组织中分离得的活游离殖子，以不同剂量的不同时间接种健康小鸡，随后用同源球虫进行攻击。效果评价指标为：（１）比较各抗原组的鸡只死亡率及盲肠病变记分；（２）各抗原组鸡只的增重差异。结果表明，柔嫩艾美尔球虫第二代裂殖子抗原不能刺激鸡体产生保护性免疫力；具有活力的裂殖子接种于健康鸡盲肠能诱发部分免疫力，但较自然感染者为 相似文献
6.
为了研究鸡艾美耳属球虫不同种在入侵细胞早期对凋亡诱导抑制的差异,将柔嫩艾美耳球虫(Eimeria tenlla)和堆型艾美耳球虫(E.acervulina)纯化的裂殖子入侵马-达氏牛肾细胞(MDBK细胞)1.5 h后,对被入侵的细胞计数并计算入侵率;加入含6%乙醇的完全培养基对细胞诱导凋亡3 h,检测细胞凋亡率。结果表明,E.tenlla裂殖子和E.acervulina裂殖子入侵率为21%和43%;凋亡诱导组的凋亡率是36.98%;柔嫩艾美耳球虫凋亡诱导组的凋亡率是25.77%;堆型艾美耳球虫凋亡诱导组的凋亡率是28.92%。柔嫩艾美耳球虫凋亡诱导组与凋亡诱导组之间差异极显著(P<0.01);堆型艾美耳球虫凋亡诱导组与凋亡诱导组之间差异极显著(P<0.01)。柔嫩艾美耳球虫凋亡诱导组与堆型艾美耳球虫凋亡诱导组之间差异显著(P<0.05)。结果提示,E.acervulina裂殖子入侵细胞并起到明显的抑制细胞凋亡作用,在入侵早期也许有类似于E.tenlla裂殖子抑制凋亡的机制;与E.tenlla裂殖子的抑制率相比略低,这可能与它的个体大小、致病能力有关。 相似文献
7.
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。 相似文献
8.
本研究旨在观察斯氏艾美耳球虫裂殖生殖阶段特异性表面抗原Es-SAG13和Es-SAG14的原核表达产物对兔的免疫保护效果.利用相对荧光定量PCR分析Es-SAGs在未孢子化卵囊时期、孢子化卵囊时期、裂殖生殖时期和配子生殖时期的转录水平,并对裂殖生殖阶段特异性表达的Es-SAG进行原核表达;然后将40只45日龄无球虫幼兔... 相似文献
9.
本文报道了柔嫩艾美耳球虫第二代裂殖子的分离纯化方法。依次通过酶消化、离心洗涤、红细胞裂解、Percoll密度梯度离心等手段对鸡柔嫩艾美耳球虫第二代裂殖子进行了分离纯化,结果表明,该法效果好,回收率高,操作程序较简单,所获得的裂殖子杂质极少,其纯度适用于进行分子生物学方面的研究。 相似文献
10.
本文从孢子生殖、裂殖生殖和配子生殖三个发育阶段对鸡球虫的内生发育研究作一系统的阐述,以期对球虫生活史有较全面的认识。 相似文献
11.
In late December 1983, 2 800 veterinarians across Canada were sent a questionnaire in order to assess the status of heartworm disease in Canada in 1983 and 26% of them responded. Veterinarians reported that 59 504 dogs were blood-tested to check for microfilariae and 771 dogs (1.30% of those tested) were found with Dirofilaria immitis. Heartworm disease was diagnosed in all provinces except New Brunswick and Newfoundland but most (733) of the cases were in Ontario. Heartworm disease was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 31% of the cases were observed with clinical signs of heartworm disease and 64% had a history of not having left Canada. Southwestern Ontario continues to be the focus of the infection and most of the dogs there had not left the province previously. 相似文献
13.
In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%). Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada. 相似文献
14.
In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%). 相似文献
15.
In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection. 相似文献
17.
In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium. 相似文献
18.
In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated. Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively. 相似文献
19.
In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%). 相似文献
20.
In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%). Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada. 相似文献
|
