• 생태와환경
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• 제47권4호
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• pp.292-301
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• 2014

Akinete germination may be a starting point of some akinete-producing cyanobacterial blooms in eutrophic freshwater systems. This study examined germinability of akinete of a cyanobacterium Anabaena circinalis isolated from the sediment of the North Han River (Cheongpyung Dam), Korea, under several environmental factors such as temperature ($5{\sim}25^{\circ}C$), light ($0{\sim}100{\mu}mol\;photons\;m^{-2}\;s^{-1}$), nutrients (nitrogen and phosphorus) and pH (5~12). The high germination rate appeared at high temperature: >55% at $25^{\circ}C$, followed by 15% at $15^{\circ}C$, $10^{\circ}C$ and 10% at $5^{\circ}C$. Low light intensity was favorable for akinete germination. Over 45% of germination occurred at low light intensities (5, 15 and $30{\mu}mol\;photons\;m^{-2}\;s^{-1}$), while less than 10% of germination occurred at both 50 and $100{\mu}mol\;photons\;m^{-2}\;s^{-1}$. No germination occurred in the dark condition. Akinete germination rate increased with nutrient (phosphorus and nitrogen) enrichment, and nitrogen addition showed greater effect on the germination compared to phosphorus addition. Akinetes germinated well at neutral or slightly alkaline pH condition (pH 7 and pH 8: >55%), but no germination was observed at pH 11~12. The present study demonstrates some favorable ambient conditions of Anabaena circinalis germination, which could provide useful information to study the germination conditions of other Anabaena species or akinete-forming algae and predict its bloom in eutrophic freshwaters.

• 한국환경생물학회:학술대회논문집
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• 한국환경생물학회 2001년도 학술대회
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• pp.87-87
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• 2001

• 한국동물학회:학술대회논문집
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• 한국동물학회 2001년도 한국생물과학협회 학술발표대회
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• pp.148.4-149
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• 2001

• 생태와환경
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• 제47권1호
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• pp.1-12
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• 2014

남조류는 겨울철에 휴면포자의 형태로 퇴적층에서 존재하다가 적합한 환경조건이 되었을 때 다시 영양세포로 전환된다. 이렇게 전환된 영양세포는 성장에 적합한 환경이 되었을 때 대량증식 하게 되어 수체 내에서 우점한다. 이전까지의 국내 대부분의 연구는 수체 내 영양세포의 변동과 환경인자와의 관계 또는 영양세포에 대한 생리생태적 연구부분에 국한되었다. 하지만, 휴면포자에서 영양세포로 진행되는 부분에 대한 연구가 조류 대량증식의 궁극적인 기작이 되므로 휴면포자에 대한 연구는 조류의 생활사를 이해하는 데에도 매우 중요하다. 또한 다른 조류들간의 변동 및 천이의 연구를 위해서도 필수적이다.

• 생태와환경
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• 제48권4호
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• pp.287-295
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• 2015

본 연구는 2014년 9월과 2015년 3월에 채수한 팔당호 3지점의 현장수 (PD-1, PD-2 및 PD-3)를 이용하여 북한강에서 우점하는 A. circinalis의 휴면포자 발아 및 성장 잠재력을 평가하였다. 질소와 인 농도는 팔당댐앞 (PD-1)과 광동교 (PD-3)에 비교하여 금남리 (PD-2)에서 좀 더 높게 나타났다. 팔당호 3지점의 총질소에 대한 영양상태지수 (TSI)는 65~85의 범위로 나타났으며, 부영양 또는 과영양 상태로 평가되었다. 또한 총인에 대한 영양상태지수(TSI) 값은 49~68의 범위로서, 중영양 또는 부영양 상태로 평가되었다. 휴면포자 발아 잠재력은 영양염 농도가 높은 금남리 지점 (PD-2)에서 좀 더 높게 나타났으며, 영양세포 성장 잠재력도 영양염 농도가 높은 현장수에서 증가하였다.

• 생태와환경
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• 제56권1호
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• pp.94-103
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• 2023

휴면포자와 같은 남조류의 휴면세포는 남조류의 초기발생 및 대발생의 중요한 씨앗세포이다. 이러한 중요성으로 인해 퇴적층에 존재하는 휴면세포를 분리하기 위해서 다양한 방법들이 시도되었다. Ludox는 해양퇴적물의 세포분리에 주로 활용되는 용액이지만 담수에서는 정확한 사용법을 찾기 어렵다. 본 연구에서는 가장 많이 사용되는 두 가지 Ludox방법(퇴적물 직접처리, 퇴적물 증류수 현탁처리)을 비교하고, 담수 퇴적물에서 남조류 휴면세포의 분리 및 유전자 증폭 효율이 높은 방법을 제안하였다. 퇴적물에서 발견된 휴면세포는 대부분 염주말목의 휴면포자로써 Dolichospermum, Cylindrospermum, Aphanizomenon의 휴면포자 형태와 유사하였다. 퇴적물을 증류수에 현탁하여 처리한 시료보다 퇴적물 그대로 사용한 시료에서 20배 더 많은 휴면포자가 발견되었으며 증류수로 현탁된 퇴적물에서는 분리되지 않은 세포가 대부분 pellet 퇴적물 표층에서 발견되었다. Ludox를 통해 층 분리된 휴면포자는 수층의 특정 깊이에서 밀집하기보다는 주로 상층과 하층에 넓게 퍼져있었다. 퇴적물을 그대로 사용한 시료에서 mibC, Geo, 16S rDNA 유전자 모두 증폭산물이 확인되었으나 퇴적물을 증류수로 현탁한 시료에서는 모든 유전자의 증폭산물이 발견되지 않았다. 따라서 담수 퇴적물에서 남조류의 휴면세포를 분리하는 경우에는 5~10 g의 퇴적물을 전처리 없이 그대로 사용하며, 퇴적물량 4배 부피의 Ludox를 첨가할 때 세포 분리 및 유전자 증폭 효율이 높았다. 본 연구에서 제시하는 Ludox 처리방법은 담수퇴적층에 존재하는 남조류 휴면세포를 분리하기 위한 방법으로써 다른 생물군에서는 동일한 효율이 나타나지 않을 수 있다. 따라서 다른 생물군의 분리에 Ludox를 적용하기 위해서는 퇴적물 전처리 방법 및 대상생물이 존재하는 수층을 파악하는 사전실험이 반드시 필요하다.

• 한국물환경학회지
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• 제32권3호
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• pp.261-270
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• 2016

We analyzed cyanobacterial community including akinete, resting cell, and benthic cyanobacteria in sediment of Bukhan, Namhan-River, Paldang-Lake, and Kyeongan-Stream and compared the physicochemical factors for water and pore water. We also performed cyanobacteria growth potential test through incubating sediment. As a result of physicochemical analysis, the concentrations of nutrients were similar for each depth of Bukhan-River. For Namhan-River and Lake Paldang sites, the concentrations of TP and DTN in bottom and deep water had higher levels. DTN in water body composed of NO3-N(73%) while DTN in pore water composed of NH3-N(77.8%). Benthic cyanobacteria in the sediment such as Oscillatoria tenuis, O. limosa, Phormidium tenue, Pseudanabaena limnetica, and Lyngbya sp. were dominant (between 0.0∼243.3×10³ cells/g, w/w). Cell densities of cyanobacteria in sediment depth of 0∼2 cm in most sites were higher compared to those in other depths. The cell density of cyanobacteria in sediment correlated with pH, conductivity, BOD5, TP, DTP, and chl. a. Increased phytoplankton and organic matters were found to be able to inhibit the growth of benthic cyanobacteria. Results of cyanobacteria growth potential test after incubating sediment revealed that harmful cyanobacteria (Anabaena, Aphanizomenon, Microcystis, and Oscillatoria) appeared at 7 days post culturing. Base on these results, the methods used in this study are considered to be able to determine the appearance of harmful cyanobacteria.

• Journal of Ecology and Environment
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• 제40권3호
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• pp.144-152
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• 2016

Background: The purpose of this study is to describe the morphological characteristics of the Aphanizomenon spp. and related species from the natural samples collected in the Nakdong River of South Korea. Results: Morphological characteristics in the four species classified into the genera Aphanizomenon Morren ex Bornet et Flahault 1888 and Cuspidothrix Rajaniemi et al. 2005 were observed by light microscopy. The following four taxa were identified: Aphanizomenon flos-aquae Ralfs ex Bornet et Flahault, Aphanizomenon klebahnii Elenkin ex Pechar, Aphanizomenon skujae $Kom{\acute{a}}rkov{\acute{a}}-Legnerov{\acute{a}}$ et Cronberg, and Cuspidothrix issatschenkoi ($Usa{\check{c}}ev$) Rajaniemi et al. Aph. flos-aquae and Aph. klebahnii always formed in fascicles; the others only occurred in solitary. Aph. flos-aquae was similar to Aph. klebahnii, whereas these species differed from each other by the size and shape of fascicles, which was macroscopic in Aph. flos-aquae and microscopic in the Aph. klebahnii. One of their characteristics was that trichomes are easily disintegrating during microscopic examination. C. issatschenkoi could be clearly distinguished from other species by hair-shaped terminal cell. Its terminal cell was almost hyaline and markedly pointed. Young populations of the species without heterocytes run a risk of a misidentification. Aph. skujae was characterized by akinete. Morphological variability of akinetes from natural samples collected in the Nakdong River was rather smaller than those reported by previous study. Conclusions: C. issatschenkoi are described for the first time in the Nakdong River. In addition, Aph. klebahnii and Aph. skujae are new to South Korea.

• 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.

• ALGAE
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• 제37권1호
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• pp.1-14
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• 2022

Cyanobacteria are distributed worldwide, and many new cyanobacterial species are discovered in tropical region. The Nostoc-like genus Amazonocrinis has been separated from the genus Nostoc based on polyphasic methods. However, species diversity within this genus remains poorly understood systematically because only one species (Amazonocrinis nigriterrae) has been described. In this study, two novel strains (NUACC02 and NUACC03) were isolated from moist rice field soil in Thailand. These two strains were characterized using a polyphasic approach, based on morphology, 16S rRNA phylogenetic analysis, internal transcribed spacer secondary structure and ecology. Phylogenetic analyses based on 16S rRNA gene sequences confirmed that the two novel strains formed a monophyletic clade related to the genus Amazonocrinis and were distant from the type species A. nigriterrae. The 16S rRNA gene sequence similarity (<98.1%) between novel strains and all other closely related taxa including the Amazonocrinis members exceeded the cutoff for species delimitation in bacteriology, reinforcing the presence of a new Amazonocrinis species. Furthermore, the novel strains possessed unique phenotypic characteristics such as the presence of the sheath, necridia-like cells, larger cell dimension and akinete cell arrangement in long-chains and the singularity of D1-D1', Box-B, V2, and V3 secondary structures that distinguished them from other Amazonocrinis members. Considering all the results, we described our two strains as Amazonocrinis thailandica sp. nov. in accordance with the International Code of Nomenclature for Algae, Fungi and Plants.