两种枝顶孢霉胞内细菌的分离鉴定及种群演替  

Isolation,identification and preliminary investigation of population succession of two endocellular bacteria from Acremonium strictum Gams.

作　　者：何培新[1] 刘伟[1] 张长铠[2] 

机构地区：[1]郑州轻工业学院食品与生物工程学院,郑州450002 [2]山东大学微生物技术国家重点实验室,济南250100

出　　处：《生态学报》2010年第8期2056-2062,共7页Acta Ecologica Sinica

基　　金：中国科学院知识创新工程重要方向资助项目(KSCXZ-YM-N-46-02-04)

摘　　要：分离、鉴定了枝顶孢霉(Acremonium strictum Gams.)2种胞内细菌,探讨了细菌在其宿主真菌菌丝细胞内的种群演替规律。结果表明,2种胞内细菌分别为不动杆菌Epbas6菌株(Acinetobacter sp.Epbas6)和地衣芽孢杆菌(Bacillus licheniformis)。镜检分析和原始分离物菌落统计表明,不动杆菌和地衣芽孢杆菌的比例为77.5∶1;然而,4℃保藏6个月的真菌分离物中不动杆菌的数量大大减少,地衣芽孢杆菌占据优势,二者的比例变为1∶50.45;而保藏12个月的真菌分离物中只有地衣芽孢杆菌。根据2种细菌的16SrDNA保守序列设计引物,分别扩增了保藏6个月和12个月的枝顶孢霉分离物,发现保藏6个月的分离物能够扩增出2种细菌的保守序列,而保藏12个月的分离物只能扩增出地衣芽孢杆菌保守序列。研究结果说明在枝顶孢霉人工培养和菌种保藏过程中,2种细菌在其宿主真菌菌丝细胞内发生着复杂的生态互作,存在着动态种群演替过程。Endocellular bacteria being localized or living inside hyphae or spores have been reported for a few fungi and the interactions between bacteria and their host fungus may have potentially beneficial functions.Acremonium strictum Gams.is a filamentous,cosmopolitan fungus with genetically diverse taxon and ecologically diverse distribution.As a polyphagous fungicolous fungus,it is able to overgrow many other fungi though it shows commensalism interactions with Psilocybe fasciata,a psychoactive mushroom as a companion fungus.Two types of bacteria,a coccobacillus and a long bacillus were accidentally observed to be released from the disruptive gap near the dilatate tip of hyphal cell of A.strictum by scanning electron microscope when studying the interactions between P.fasciata and A.strictum.The existence of these endobacteria was further confirmed by fluorescence microscopy.In the present study,two endocellular bacteria,Acinetobacter sp.Epbas6 and Bacillus licheniformis,were isolated from hyphae of A.strictum and identified on the basis of their morphological and biochemical characteristics combined with sequence analysis of 16S rDNA.The pattern of population succession of these two bacteria during their host strain storage was also preliminarily investigated.The ratio of these two bacteria was about 77.5 to 1 based on micrographical and statistic analysis of colony numbers from the original isolates.However,in isolates of fungus preserved at 4℃ for 6 months,B.licheniformis predominated over Acinetobacter sp.Epbas6 with the ratio being 50.45 to 1.Only B.licheniformis was observed in isolates of A.strictum preserved at 4℃ for 12 months.Consistent with above results,the 16S rDNA sequences of both bacteria were able to be detected by multiplex PCR using specific primers from the isolate of A.strictum preserved at 4℃ for 6 months while only that of B.licheniformis was amplified from the isolate preserved at 4℃ for 12 months.These results suggest that a complex interaction might exist between the two endocellula

关 键 词：枝顶孢霉 胞内细菌 不动杆菌Epbas6 地衣芽孢杆菌 种群演替 

分 类 号：Q938[生物学—微生物学]