생태와 환경 Vol. 50 No. 1 (p.137-147)

낙동강에서 분리된 Aphanizomenon flos-aquae (Cyanophyceae) 균주의 목 표 유 전자를 이용한 잠재적 독 소 생성능 및 계통학적 분 석

Analysis of Potential Toxigenicity and Phylogeny using Target Genes in Aphanizomenon flos-aquae (Cyanophyceae) strains isolated from the Nakdong River.
키워드 :
cyanobacteria,cylindrospermopsin,saxitoxin,16S rRNA,nostocales

초록

The identity of toxin producers remains only hypothesis unless there were identified by strain isolation and analytical confirmation of both the cyanotoxin production and the genetic identity of the monoculture. The purposes of this study were to identify a morphologic and phylogenetic classification in Aphanizomenon flos-aquae strains isolated from the Nakdong River and to investigate the potential ability of the strains to produce toxins such as saxitoxin and cylindrospermopsin using target genes. The 16S rRNA and sxtA, sxtI, cyrA, cyrJ genes were analyzed on two strains (DGUC001, DGUC003) isolated from the Nakdong River. Morphological features of the strains were observed a shape of aggregated trichomes in parallel fascicles which can reach up to macroscopic size and a hyaline terminal cell without aerotope. In addition, the 16S rRNA phylogenetic analyses showed that the strains were identified as the same species with high genetic similarity of 98.4% and grouped within a monospecific andsupported cluster I of Aphanizomenon flosaquae selected from GenBank of the NCBI. The cyrA and cyrJ genes encoding for the cylindrospermopsinbiosynthesis were not detected in the present study. The sxtA gene was in detected both the two strains, whereas the sxtI gene which had been suggested as a suitable molecular marker to detect saxitoxin-producing cyanobacteria was not found both the strains. Thus, the two strains isolated from Nakdong River were identified as the same species of Aphanizomenon flos-aquae Ralfs ex Bornet et Flahault 1888, the two strains were confirmed as potential non-producing strains of the saxitoxin and cylindrospermopsin.