顶复门原虫是一类专一性的胞内寄生性原虫,其种类丰富、分布广泛,包括艾美耳球虫、巴贝斯虫、隐孢子虫、疟原虫和弓形虫等.此类原虫具有保守的棒状体、致密颗粒以及微线等顶端复合器结构,这些细胞器可分泌大量的入侵相关蛋白分子介导虫体入侵宿主细胞.而棒状体蛋白是这类原虫在入侵过程中由棒状体分泌的一类蛋白,其在虫体入侵宿主细胞、纳虫空泡形成及胞内虫体的增殖调控等方面发挥着至关重要作用,是最具潜力的疫苗候选抗原.本文对棒状体蛋白的发现、组成、功能及定位进行概述,以目前研究最深入的弓形虫棒状体蛋白为主,归纳总结近年来关于棒状体蛋白作为顶复门原虫疫苗候选分子的研究进展,以期为新型抗原虫分子疫苗的研制提供理论依据.

坏死性肠炎(necrotic enteritis,NE)是家禽中最重要的肠道疫病之一,呈世界性流行,严重危害养鸡业发展.人工复制鸡坏死性肠炎病例是研究该病发病机制及筛选有效药物的重要手段,然而在实际试验过程中,通常受实验动物、感染菌株、诱导病原等多方面因素影响而难以成功复制病例.鉴于此,现综述了影响鸡坏死性肠炎病例成功复制的关键因素,包括攻毒使用的实验动物、菌株毒素、菌株培养条件、诱导病因等,同时探讨了如何通过调整这些因素来改善人工复制鸡坏死性肠炎病例的严重程度,分析了鸡坏死性肠炎病例的病变评分系统,以期为鸡坏死性肠炎的实验室研究及综合防控提供理论基础.

Abstract Background Poultry necrotic enteritis (NE) is an economically important disease caused by C. perfringens. The disease causing ability of this bacterium is linked with the production of a wide variety of toxins. Among them, necrotic enteritis B-like (NetB) toxin is reported to be involved in the pathogenesis of NE; in addition there is some circumstantial evidence that tpeL toxin may enhance virulence, but this is yet to be definitely shown. The situation becomes more complicated in the presence of a number of predisposing factors like co-infection with coccidia, type of diet and use of high protein diet. These co-factors alter the intestinal environment, thereby favoring the production of more toxins, leading to a more severe disease. The objective of this study was to develop a successful animal model that would induce clinical signs and lesions of NE using C. perfringens type G strains obtained from field outbreaks. A separate trial was simultaneously considered to establish the role of dietary factor with coccidial co-infection in NE. Results The results have shown that use of net-B positive C. perfringens without predisposing factors induce moderate to severe NE (Av. Lesion score 1.79 ± 1.50). In a separate trial, addition of fish meal to a feed of C. perfringens challenged birds produced higher number of NE cases (Av. Lesion score 2.17 ± 1.28). However, use of less virulent E. necatrix strain along with fish meal in conjunction with net-B positive strain did not alter the severity of NE lesions in specific pathogen free chicken (Av. Lesion score 2.21 ± 1.13). Conclusions This study suggests that virulent C. perfringens type G strains can induce NE lesions in the absence of other predisposing factors. Birds in the clostridia challenged group showed moderate to severe NE lesions. Use of less virulent coccidia strain contributed to a lesser extent in increasing the severity of disease. Maize based diet along with fishmeal (1:1) increased the severity of lesions but statistically it was non-significant. The NE lesions in all experimental groups were found to be present more frequently in the duodenum. In this way, this study provided an effective model for in vivo production of NE in poultry birds.

为了调查广东粤北地区产气荚膜梭菌的分子流行病学,研究其对于粤北地区养鸡业的危害,以及鸡坏死性肠炎在粤北地区的流行情况.本研究从粤北地区(韶关、清远)15个规模化养鸡场150栋鸡舍共计采集3 000份新鲜粪便样本,分别将每栋鸡舍20份粪样混为1份样品提取核酸,并针对产气荚膜梭菌所特有的cpa毒素基因及7种毒素型的特异性毒素基因分别进行荧光定量PCR检测,结果共检测出cpa毒素阳性样品32份,占总样品的21.33％.cpa阳性样品的其他毒素基因检测均为阴性,表明所检测32份阳性样本均为A型产气荚膜梭菌.结果 表明A型产气荚膜梭菌在粤北地区养鸡场普遍存在,可能是粤北地区鸡坏死性肠炎的重要病原.

鸡坏死性肠炎是由产气荚膜梭菌引起的一种严重危害养鸡业发展的肠道细菌病.为明确珠三角地区鸡群中产气荚膜梭菌的流行情况及其对当地养鸡业可能带来的危害,本研究在珠三角地区10个规模化养鸡场100栋鸡舍,共采集2500份粪便样品,分别将每栋鸡舍25份粪样混为1份样品提取核酸,针对产气荚膜梭菌α毒素(CPα)编码基因cpa及7种毒素型的特异性毒素基因分别进行荧光定量PCR(Real?time PCR)检测.结果显示:在珠三角地区所采集的粪样中,共检测出α毒素阳性样品35份,占总样品的35％,阳性检出率35％.对α毒素阳性样品进行其他毒素基因的Real?time PCR检测,结果均为阴性,说明所检测35份阳性样品均为A型产气荚膜梭菌.结果表明珠三角地区养鸡场广泛流行A型产气荚膜梭菌,感染率为35％.本论文研究结果为珠三角地区鸡群中A型产气荚膜梭菌的流行规律研究及防控提供临床数据.