Development of detection method for algal-lytic bacteria in eutrophic lakes.

为了用FISH法检测溶藻细菌，从富营养化湖泊中分离到溶藻细菌菌株，并对其遗传特性进行了分析。从日本9个富营养化湖泊中分离到29株溶藻细菌。泰国和中国也使用包括铜绿微囊藻(NIES-90)在内的琼脂平板作为细菌的底物。来自与世隔绝的巴特里亚。提取DNA，对16S rDNA序列进行分析，将其分为3组。A组细菌的16S RDNA序列与黄单胞菌非常相似，其细胞长度为2μm以上(有时为5 pm以上的线状状态)，鸟嘌呤-环鸟苷含量很高，为68-70%。在A组分离株中，泰国北部和曼谷分离的3株细菌的16S rDNA序列一致，但日本和内蒙古分离株的16S rDNA序列基本相同。另一类细菌(B)为短杆状细菌，鸟嘌呤-胞嘧啶含量约为59-62%，在16S rDNA序列上与假单胞菌等假单胞菌相近。通过对藻类分解细菌共有的特定DNA序列的研究，发现细菌不存在与溶藻细菌相近的黄单胞菌，该DNA序列由21个碱基对组成。根据这些DNA序列，用FISH方法从现场样品中特异性地检测到溶藻细菌的可能性。

For detection of algal-lyiic bacteria by FISH method, such bacterial strains were isolated from eutrophic lakes, and analysed genetic property. Total of 29 strains of algal-lyiic bacteria were isolated from 9 eutrophic lakes in Japan. Thailand and also China by using agar plates including Microcystis aeruginosa (NIES-90) as substrate for the bacteria. From the isolated bacte ria. DNA was extracted and the 16S rDNA sequence was analysed to classify the bacteria into three groups. The 16S rDN A sequence of the bacteria belonging to a group (A), of which cell length was 2 μ m over (the thread state of at times 5 p m over) and the guanine-cyiosine content was very high with 68-70%, was very similar to those of Xanthomonas. Amon g the bacterial strain of group (A), 16S rDNA sequences of 3 strains isolated from north Thailand and Bangkok agreed, an d although difference is partially seen on the sequences, the sequences of isolates from Japan and Inner Mongolia were simi lar. Bacteria belonging to another group (B), which were short rods, guanine-cytosine contents were about 59-62%, seemed to be near of Pseudomonas such as Pseudomonas mendocina from the sequence for 16S rDNA. As a result of research for the specific DNA sequence which are common to the algae decomposition bacteria, DNA sequence that consists of 21 base pairs was found out that absent to the bacteria belong Xanthomonas which is near to the algal-lyiic bacteria. The possibilit y that is able to detect the algal-lytic bacteria specifically from in situ samples by the FISH method on the basis of these DNA sequence was shown.