热带太平洋深海微生物的若干生理生态特征

Physiological and ecological characteristics of the deep-sea microorganisms in tropical Pacific Ocean

从2001年春、秋季于热带太平洋区采集到的深海样品中共分离到110株微生物,从中挑取31株进行形态特征和对环境理化因子适应特征的研究,同时利用Biolog微生物自动鉴定系统进行菌种鉴定和碳源代谢分析.结果表明:31株微生物中2株为酵母,21株为革兰氏阳性细菌,8株为革兰氏阴性细菌,来自底质的细菌菌株阳性菌占优势,而海水、蓝藻中阴性菌居多;温度、盐度、pH适应性试验表明,严格意义上的狭适性微生物不到总数的1/3,而具有较宽生态幅的广适性微生物占有相当大的比例.另一方面,耐冷菌、中度嗜盐菌和抗碱菌在这些微生物中的比例很高,同时,来自蓝藻的菌株大多数在4℃下不生长,而来自上覆水和底质的菌株可在4℃生长,这些都体现了微生物对生存环境的响应.31株微生物经Biolog鉴定12株得出鉴定结果.15株革兰氏阳性细菌对95种碳源的利用能力分析表明,不同菌株可利用碳源的数目从3种到46种不等,差异很大,体现了深海微生物营养类型的极大多样性;同时,发现有8种碳源可被一半以上的受试菌株所利用,这些碳源均是微生物各类代谢途径中的重要中间代谢物.

31 cultures of the 110 microbial strains, which were isolated from deep--sea samples taken in tropical Pacific Ocean in Summer and Autumn, 2001, were selected for this research. The characters of their morphologies and of their adapting to the physical and chemical factors were studied, and the identification of these strains and their carbon-utilizing patterns were performed by Biolog Microstation System. The results demonstrated that the tested strains consisted of 2 yeasts, 21 Gram-positive bacteria and 8 Gram-negative bacteria, of which the Gram-positive bacteria were dominant in the sediment samples while the Gram-negative bacteria were in the majority in the samples of sea waters and blue--green algaes. The adaptability of these strains for different environmental factors （temperature, salinity and pH） was studied and it was found that less than 1/3 of the tested strains showed stenotropic adaption to the environmental factors, while a large proportion of the cultures was eurytropic microorganisms with wide ecological amplitude. On the other hand, among these microorganisms, psychotrophs, moderate halophiles and alkalitolerant bacteria were in very high percentages. Furthermore most of the strains from blue-green algae samples could not, but those from over-laid water and sediment samples were able to, grow at 4 ℃. All these results incarnated the response of microorganisms to their living environments. 12 strains of the total tested microorganisms could be given the taxonomic results by the database of Biolog Microstation System. According to the carbon-utilizing spectra of the 15 strains of Gram-positive bacteria vs 95 types of organic carbons in Boilog GP2 Microplates, the numbers of the utilizable carbon sources showed a great range from 3 to 46 single organic carbons for each strain, embodying the great diversity of nutrition types in deep sea microorganisms. Among the utilizable carbons, 8 types could be used by more than half of the tested Gram-positive bacteria. These organic carbon sources are the important intermediate metabolite in all kinds of metabolic pathway for microorganisms.