佛坪自然保护区大熊猫蛔虫感染调查及蛔虫进化分析

发布时间：2018-03-31 10:45

本文选题：大熊猫　切入点：施氏贝蛔虫　出处：《东北林业大学》2015年硕士论文

【摘要】：大熊猫是我国特有的珍贵濒危动物,是野生动物保护中的旗舰物种,被誉为“活化石”,现存的主要栖息地是四川、陕西和甘肃的山区。蛔虫是大熊猫最为常见的寄生虫,危害极大。本研究扩增了大熊猫蛔虫的ITS和5.8S序列,并结合已有的18S基因序列研究其在蛔虫目中的进化地位,并对佛坪自然保护区野生大熊猫蛔虫病的流行进行了为期一年的监测,评估温度、露点、海拔、竹型等非生物因子对其的影响。2012年,在陕西省佛坪国家级自然保护区共采集193份大熊猫粪便样品。采用饱和食盐水漂浮法对样品中的虫卵进行分离,并通过形态学鉴定虫卵。结果显示101份为阳性,并且鉴定为施氏贝蛔虫。此外,采用分子生物学手段扩增获得了阳性样品中施氏贝蛔虫的ITS-1、5.8S和ITS-2基因片段。基于5.8S和ITS-2基因序列的进化分析结果表明大熊猫蛔虫属于贝蛔属,与转移拜林蛔虫亲缘关系最近。基于ITS-1和18S基因序列的进化分析表明蛔虫与宿主存在紧密的协同进化关系,动物蛔虫进化存在两个起源点,即哺乳动物单独起源于一个点,鸟类起源于另外一个点。利用麦克马斯计数法进行粪样中虫卵的检测,结果显示,佛坪自然保护区大熊猫施氏贝蛔虫的年度感染率为52.3%(101/193),全年平均感染强度89.27个/g,单个个体感染强度最高达到1147个/g。从4月份开始感染强度与感染率开始上升,6、7月份达到顶峰,后逐渐下降。此外,流行病学监测结果显示施氏贝蛔虫流行存在季节与区域差异：春夏季蛔虫的感染率(71.0%、77.4%)显著高于秋冬季蛔虫的感染率(22.5%、18.4%),春夏季蛔虫的平均感染强度(167.74个/g、119.81个/g)显著高于秋冬季的平均感染强度(9.25个/g、2.89个/g),巴山木竹林区大熊猫蛔虫平均感染强度(125.0个/g)显著高于秦岭箭竹区域(50.8个/g)。相关性分析表明：温度与感染强度呈正相关(r=0.328,p0.01),温度高于15℃后,施氏贝蛔虫的感染率与感染强度都显著增高；露点与感染强度呈正相关(r=0.328,p0.01)；海拔与感染强度呈负相关(r=-0.224,p0.01)。
[Abstract]:Giant panda is a rare and endangered animal in China and a flagship species in wildlife conservation. It is known as a "living fossil". The main habitat is Sichuan, Shaanxi and Gansu mountains.Ascaris lumbricoides are the most common parasites in giant pandas and are extremely harmful.In this study, the ITS and 5.8S sequences of Ascaris lumbricoides were amplified, and their evolutionary status in the order Ascaris lumbricoides was studied in combination with the existing 18s gene sequence, and the epidemic of Ascaris lumbricoides in wild pandas in Foping Nature Reserve was monitored for one year.Temperature, dew point, altitude, bamboo type and other abiotic factors were evaluated. In 2012, 193 samples of giant panda feces were collected in Foping National Nature Reserve, Shaanxi Province.The eggs in the samples were separated by saturated salt floatation, and the eggs were identified by morphology.The results showed that 101 samples were positive and identified as Ascaris skrjabii.In addition, the ITS-1 5.8S and ITS-2 gene fragments of Ascaris skrjabini in positive samples were amplified by molecular biology.The phylogenetic analysis based on 5.8S and ITS-2 gene sequences showed that the giant panda ascariasis belongs to the genus Ascaris, which is closely related to Ascaris suum.The evolutionary analysis based on ITS-1 and 18s gene sequences shows that there is a close coevolution relationship between Ascaris lumbricoides and its host. There are two origin points in the evolution of Ascaris lumbricoides in animals, that is, mammals originate from one point alone and birds from another point.The results showed that the annual infection rate of Giant Panda Ascaris Schermani in Foping Nature Reserve was 52.3% 101 / 1931%, with an average infection intensity of 89.27 / g and the highest infection intensity of 1147 / g / g per individual in the whole year.The infection intensity and infection rate began to rise in April and peaked in July and then declined gradually.In addition,The average infection intensity of the giant panda ascariasis in the bamboo forest area of Bashan Mountain (125.0 / g) was significantly higher than that in the Qinling Bamboo region (50.8 / g).
【学位授予单位】：东北林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S858.93

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