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

采用FISH方法从富营养化湖泊中分离溶藻菌，分析其遗传特性。从日本9个富营养化湖泊中分离到29株溶藻菌。泰国和中国也使用包括铜绿微囊藻（ies -90）在内的琼脂板作为细菌的底物。从分离的细菌中。提取DNA，分析16S rDNA序列，将细菌分为三组。该菌属细胞长度为2 μ m以上（线程状态为5次p m以上）的A群，其16S rDN A序列与黄单胞菌非常相似，鸟嘌呤-胱氨酸含量高达68 ~ 70%。在(A)群菌株中，从泰国北部和曼谷分离的3株菌株的16S rDNA序列一致，虽然在序列上存在部分差异，但从日本和内蒙古分离的菌株的序列相似。另一类细菌(B)为短棒状，鸟嘌呤-胞嘧啶含量约为59 ~ 62%，从16S rDNA序列来看，与mendocina假单胞菌相近。通过对藻类分解菌共有的特定DNA序列的研究，发现该菌缺少21个碱基对的DNA序列，属于接近解藻菌的黄单胞菌。结果表明，基于这些DNA序列，FISH方法能够从原位样品中特异性检测出溶藻菌。

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.