Kunttu Heidi M T, Suomalainen Lotta-Riina, Jokinen E Ilmari, Valtonen E Tellervo
University of Jyväskylä, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 Jyväskylä, Finland.
Microb Pathog. 2009 Jan;46(1):21-7. doi: 10.1016/j.micpath.2008.10.001. Epub 2008 Oct 17.
Four different colony morphologies were produced by Flavobacterium columnare strains on Shieh agar plate cultures: rhizoid and flat (type 1), non-rhizoid and hard (type 2), round and soft (type 3), and irregularly shaped and soft (type 4). Colonies produced on AO agar differed from these to some extent. The colony types formed on Shieh agar were studied according to molecular characteristics [Amplified Fragment Length Polymorphism (AFLP), Automated Ribosomal Intergenic Spacer Analysis (ARISA), and whole cell protein SDS-PAGE profiles], virulence on rainbow trout fingerlings, and adhesion on polystyrene and fish gills. There were no molecular differences between colony types within one strain. Type 2 was the most adherent on polystyrene, but type 1 was the most virulent. Adhesion of F. columnare strains used in this study was not connected to virulence. From fish infected with colony type 1, three colony types (types 1, 2 and 4) were isolated. Contrary to previous studies, our results suggest that strong adhesion capacity may not be the main virulence factor of F. columnare. Colony morphology change might be caused by phase variation, and different colony types isolated from infected fish may indicate different roles of the colony morphologies in the infection process of columnaris disease.
根状和平坦型（1型）、非根状和坚硬型（2型）、圆形和柔软型（3型）以及不规则形状和柔软型（4型）。在AO琼脂上产生的菌落与这些菌落有所不同。根据分子特征[扩增片段长度多态性（AFLP）、自动核糖体基因间隔区分析（ARISA）和全细胞蛋白SDS-PAGE图谱]、对虹鳟鱼苗的毒力以及在聚苯乙烯和鱼鳃上的黏附情况，研究了在谢氏琼脂上形成的菌落类型。同一菌株内的菌落类型之间没有分子差异。2型在聚苯乙烯上的黏附性最强，但1型的毒力最强。本研究中使用的柱状黄杆菌菌株的黏附与毒力无关。从感染1型菌落的鱼中分离出了三种菌落类型（1型、2型和4型）。与先前的研究相反，我们的结果表明，强黏附能力可能不是柱状黄杆菌的主要毒力因子。菌落形态变化可能是由相变引起的，从感染鱼中分离出的不同菌落类型可能表明菌落在柱状病感染过程中的不同作用。
