• 한국환경과학회지
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• 제27권1호
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• pp.27-38
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• 2018

This study was carried out in the Bukhan River in the summer of 2014 and 2015, to identify the relationship between geosmin and the morphological changes in Anabaena. Identification of Anabaena was conducted using morphological and molecular analyses. Anabaena in this study was similar to Anabaena circinalis, A. crass, and A. spiroides with regard to regular coils, vegetative cell, akinete shape, and size, hoever, it was distinguishabl from A. crass and A. spiroides because of its larger trichome coil size. Additionally, the sequences of phycocyanin (PC) gene from Anabaena showed a 99% genetic similarity with A. circinalis NIES-1647 strain. The coil diameter of trichome ranged from 106 to $899{\mu}m$, and the diameter and abundance showed an insignificant positive correlation (r=0.544, p<0.05). The result of relationship between the coil diameter and the cell number per 360-degree rotation was kept at $33.8{\pm}5.2$ cells per $100{\mu}m$ diameter despite variable diameter. The average geosmin concentrations in 2014 and 2015 were investigated to be 99 ng/L and 35 ng/L, respectively. A. circinalis cell density contributed considerably to the change in geosmin and was positively correlated with geosmin concentration (2014; r=0.599, p<0.01, 2015; r=0.559, p<0.01). Our results suggest that geosmin and coil diameter could be estimated with the help of cell density.

• 미생물학회지
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• 제45권3호
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• pp.268-274
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• 2009

건강보조식품 등으로 이용되는 Arthrospira platensis는 세계적으로 대량생산되고 있으나 생산공정 중 수확단계에서 많은 비용이 소요된다. 본 연구에서는 부상을 이용한 효과적인 수확을 위해 균주의 개량을 시도하였으며, 개량균주의 생리적 물리적 특성을 파악하고자 하였다. Ethyl methanesulfonate (EMS)를 모균주 A. platensis KCTC AG20590에 0.24%의 농도로 10, 20, 30분씩 처리하여, 형태 및 부상성이 우수한 균주 A. platensis M20CJK3 균주를 분리하였다. A. platensis M20CJK3은 느슨한 형태에서 촘촘한 형태로 세포사(trichome)의 길이 및 코일간 간격이 감소하였으며, 생장 및 $CO_2$ 고정능이 각각 15%, 17% 향상되었다. 또한, 개량균주의 부상성은 모균주에 비해 2배 이상 향상되었다. 이차원 전기영동 분석을 통해 모균주와 개량균주의 단백질 발현양상을 비교분석한 결과 광합성 관련 색소의 구조와 광전자전달계에 관련된 단백질의 발현 양상이 차이를 보였다. 본 연구에서 개발된 A. platensis M20CJK3은 고밀도 대량배양 및 수확에 유리하며, A. platensis 유전자 연구의 유용한 모델 균주로 활용될 수 있을 것으로 사료된다.

• ALGAE
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• 제33권2호
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• pp.143-156
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• 2018

Dolichospermum is a filamentous and heterocytous cyanobacterium that is one of the commonly occurring phytoplanktons in the Han River of Korea. Morphological observations led to the identification of D. planctonicum-like filaments in seasonal water samples. In the present study, we successfully isolated these filaments using culture methods, and examined its morphology using light and scanning electron microscopy. The morphology of the D. planctonicumlike species differed from that of typical D. planctonicum; it had thin cylindrical-shaped akinetes, which were narrower towards the ends than at the center. This morphology is firstly described in the genus Dolichospermum. In addition, the akinetes in the filament developed solitarily and were distant from the heterocytes. Phylogenetic analysis of the 16S rRNA sequences showed that our Dolichospermum clustered with D. planctonicum and D. circinale, which have coiled trichome. However, phylogenetic analysis of the gene encoding rivulose-1,5-bisphosphate carboxylase (rbcLX) clearly separated our species from other Dolichospermum, forming a unique clade. Additionally, structures of D. planctonicum and D. hangangense strains were different type in Box-B and V3 region. These results demonstrated that the new Dolichospermum species was unique in morphology and molecular traits. Therefore, we propose this to be a new species belonging to genus Dolichospermum with the name Dolichospermum hangangense sp. nov.