群体微囊藻附生细菌特性

附生细菌在微囊藻水华暴发过程中可能发挥了重要作用,但是,缺少关于微囊藻附生细菌特性的研究报道.本文从4种群体微囊藻(铜绿微囊藻、惠氏微囊藻、水华微囊藻和坚实微囊藻)中分离得到了18种附生细菌,分别隶属于六大类群:α-变形菌纲、β-变形菌纲、γ-变形菌纲、放线菌纲、纤维粘网菌纲和黄杆菌纲.BIOLOG板分析显示除了α-变形菌纲中的2种细菌以及放线菌纲中的1种细菌以外,其余细菌都能够利用10种以上的碳源.18种附生细菌中有12种具有趋化性,12种具有疏水性,14种具有自聚能力.除了黄杆菌纲菌株都具有亲水性外,其余5大类群菌株都含有疏水性种类.六大类群中都含有具有趋化性和自聚能力的种类.每种微囊藻中的大多数附生细菌种类都能利用10种以上的碳源,都具有疏水性.每种微囊藻中至少有一组细菌表现出共聚能力.除了水华微囊藻外,其余3种微囊藻中附生细菌的大多数种类都具有趋化性.除了惠氏微囊藻外,其余3种微囊藻的附生细菌中大多数种类都具有自聚能力.结果显示细菌旺盛的代谢潜力、趋化性、疏水性、自聚能力和共聚能力可能有利于附生细菌定殖于微囊藻群体.

Characterization of epiphytic bacteria associated with colonial Microcystis

Epiphytic bacteria associated with colonial Microcystis may play an important role in the development of cyanobacterial bloom. However, information on characterization of Microcystis-associated bacteria is limited. In this study, eighteen Microcystis-associated bacteria which belonged to six bacterial groups: Alpha proteobacterium, Beta proteobacterium, Gamma proteobacterium, Actinobacteria, Cytophagia and Flavobacteriia, were isolated from four Microcystis species (M. wesenbergii, M. flos-aquae, M. firma and M. aeruginosa). Analysis by BIOLOG plate indicated that except for two isolates of Alpha proteobacterium and one isolate of Actinobacteria, the other isolates were capable of utilizing more than 10 carbon sources. Among 18 bacterial isolates, 12 isolates showed chemotaxis, 12 isolates displayed hydrophobicity, and 14 isolates exhibited autoaggregation ability. Except for Flavobacteriia, other five groups contained hydrophobic bacterial isolates. All six groups contained bacterial isolates with chemotaxis and autoaggregation ability. Most of bacterial isolates associated with each Microcystis species were capable of utilizing more than 10 carbon sources, and exhibited hydrophobicity. For each Microcystis species, there was at least one group of bacterial isolates exhibiting coaggregation ability. Except for M. flos-aquae, most of bacterial isolates associated with each of other three Microcystis species showed chemotaxis. The results indicated that active metabolic potential, chemotaxis, hydrophobicity, and the abilities of autoaggregation and coaggregation might help the bacteria colonize the Microcystis colonies.