进食对家蝇成虫肠道共生细菌组成和数量的影响

Effects of feeding on the composition and quantity of intestinal symbiotic bacteria in houseflies (Musca domestica)

目的了解进食对家蝇成虫肠道共生菌数量和种类的影响。方法刚羽化的家蝇随机分为正常喂食组和未喂食组,每天分雌、雄取样,解剖肠道后,分离其肠道内细菌,直到全部死亡。家蝇肠道共生细菌采用传统方法分离培养。挑取形态有差异的单菌落,于LB培养基中摇菌过夜,提取DNA,进行16srDNA基因扩增,扩增产物测序,并在NCBI中进行序列比对,鉴定到属,计数家蝇不同虫态肠道中分离到的细菌菌属数,分析其变化。结果在家蝇成蝇肠道内共分离到共生菌17属,其中正常进食成蝇分离到12属,未进食成蝇肠离到10属,两组共有细菌6属,分别为普罗威登斯菌属、葡萄球菌属、香味菌属、克雷伯菌属、假单胞菌属和不动杆菌属。正常喂食的家蝇肠道中特有的细菌有7属,分别为苍白杆菌属、鞘氨醇杆菌属、肠球菌属、寡养单胞菌属、土壤杆菌、代尔夫特菌属和漫游球菌属;未喂食家蝇肠道中特有的细菌有4属,分别为白色杆菌属、肠杆菌属、短状杆菌属和微杆菌属。正常喂食组不同日龄雌虫和雄虫肠道中分离到的共生细菌菌属数量差异有统计学意义(F值分别为5.57和3.57,P<0.05或P<0.01);未进食组不同日龄雌虫和雄虫肠道中分离到的共生细菌菌属数量差异无统计学意义(F值分别为0.17和0.92,P>0.05)。结论进食不但可影响家蝇的寿命,还可影响家蝇成虫体内的肠道共生细菌的组成,推测其肠道共生细菌可能部分来自于食物和生活环境。

Objective To ascertain the effects of diet on the composition of symbiotic bacteria in the gut of adult Musca domestica. Methods Newly emerged adult houseflies were randomly divided into two groups. One group was fed with brown sugar and water and the other group was given no food or water. The two groups of houseflies were divided into males and females every day until all the flies died. The gut was dissected with a sterile blade and bacteria were isolated using conventional methods. Single colonies with a differing morphology were isolated and cultured on LB medium. DNA of different bacteria were extracted and the 16S rDNA gene was amplified and sequenced. The sequenced gene fragments were aligned with data from the NCBI database to determine the genus of different bacteria. Results Seventeen genera of bacteria were isolated from adult houseflies. Twelve genera were isolated from fed houseflies and 10 genera were isolated from non-fed houseflies. Six genera of bacteria were isolated from both groups of houseflies, including Providencia, Staphylococcus, Myroides, Klebsiella, Pseudomonas, and Acinetobacter. The bacteria Ochrobactrum, Sphingobacteri urn, Enterococcus, Stenotrophomonas, Agrobacterium, Del ftia, and Vagococcus were only isolated from fed Musca dora estica adults. The bacteria Leucobacter, Enterobacter, Brachybacterium, and Microbacterium were only isolated from non fed adults. The number of genera of bacteria isolated from fed female adults （F--5.57, P= 0. 004） differed significantly from the number isolated from male adults （F=3.57, P=0.02） of different ages （in days）, but the number of genera of bacteria isolated from non-fed female adults （F=0.17, P=0.92） did not differ significantly from the number isolated from male adults （F=1. 07, P=0.42） of different ages （in days）. Conclusion Feeding affects the longevity of Musca domestica adults and it also affects the symbiotic bacteria found in those adults. Presumably, some of the symbiotic bacteria found in Musca domestica adults come from the diet of those houseflies and their living conditions.