• ALGAE
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• 제22권2호
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• pp.131-139
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• 2007

The expression of genes responding to cold stress in a freshwater alga, Spirogyra varians, was studied by using differential expression gene (DEG) method. A gene strongly up-regulated in 4°C was isolated and designated as SVCR2 (Spirogyra varians cold regulated) gene. The cDNA encoding SVCR2 was cloned using λZAP cDNA library of Spirogyra varians. The deduced amino acid had a sequence similarity with trans-membrane protein in Arabidopsis thaliana (Q9M2D2, 52.7%). Northern blot analysis demonstrated that transcript level of SVCR2 increased about 10 fold under low temperature (4°C), compared with that cultured at warm (20°C) conditions. The expression of SVCR2 was also affected by light conditions. When the plants were exposed to high light (HL) (1200 μmol photon m–2 s–1), the expression of SVCR2 began within 2 hrs. This gene expression lasted for 4 hrs and decreased afterwards. Under the blue light (470 nm) condition, the expression of this gene was induced in same way as HL treatment, even under less than 100 μmol photon m–2 s–1. But red light (650 nm) and UV-A irradiation did not affect the expression of SVCR2.

• 생명과학회지
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• 제8권2호
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• pp.173-180
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• 1998

미세 조류의 항균성 탐색을 위해 베를린 공대 생물공학 연구실에서 좀 균주을 분양받아 독일 현지 연구실에서 연구를 행하였다. 6종의 미세 조류로부터 항균성 시험 시료응 획득하기위해 먼저 배양데 따른 미세 죠류 배양액의 변화를 pH와 균제량으로 관찰하였고, 이를 토대로 시험 시료를 대주중식기와 정기기 두 구간으로 나누어 채취하였다. 얻어진 시료를 균체와 균체 상층액으로 분리하여 각족 용매를 이용하여 분획을 행하여 4-7종의 획분들 얻었거 이들이 가지는 항균 활성을 시험하였다. BGA(blue green algae) 4종류 중에서 Lsp(lyngbya sp.)와 Tsp(Tetraselmis sp.)에서 항균활성이 관측되었는데, 특히 균체외 상층액의 dthyl acetate 추출 획분이 서균과 특히 곰팡이에 대해 강력한 항균 활성이 있는 것으로 확인되었고, 그뢰 2종의 BGA 와 2종의 규조류(diatoms)에서는 항균 활성 획분이 확인되지 않았다.

• Ocean and Polar Research
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• 제43권3호
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• pp.127-140
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• 2021

At the estuaries of Bonggang and Miryong streams in the Korean southern coast, the spatiotemporal distribution and habitat environment of a nerite snail, Clithon retropictum (Gastropoda: Neritidae), which has been assigned as a legally protected species of Korea, were explored. Physicochemical environmental factors such as water temperature, salinity, tidal level distribution as well as biotic environments (chlorophyll-a concentration and epilithic microalgae composition) were monitored every month. The relationships between the environmental factors and spatiotemporal distribution of the nerite snail population were analyzed. Water temperature, salinity, and water level varied by season and lunar tidal rhythm. The spatiotemporal distribution of the nerite snail was mostly related to water salinity. Among epilithic algae which were the priority prey of snails, blue-green algae and green algae dominated in summer and autumn, while diatoms predominated during winter and spring. Chlorophyll-a concentration was highly and positively correlated with the population density of the nerite snail. The correlation coefficients were different depending on the taxon (Family) of epilithic algae. The mean population density was 302.2 inds m^-2 and 271.8 inds m^-2 in Bonggang Stream and Miryong Stream, respectively. The egg capsules of the nerite snail in the two habitats were observed from March (in Bonggang Stream) or April (in Miryong Stream) to August, and newly hatched juveniles recruited in the habitats from August were assessed with regard to frequency distributions of shell width. The occurrence of large-sized snails in upper stream reaches of both Bonggang and Miryong indicated the movement of spats from the mouth to the upper reaches during the whole life cycle.

• Journal of Plant Biology
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• 제34권2호
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• pp.165-173
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• 1991

본 연구기간 중 인천항 선거내에서 생육하는 해조군집을 1990년 1월부터 12월 사이에 종조성, 우점종 그리고 수직분포를 정성, 정량적인 방법으로 조사하였다. 조사기간 중 6월에 blooming에 의한 큰 교란을 받아 기존하던 해조군집이 완전히 파괴되는 사건이 발생하여 새로운 저층에 대한 군집의 착생과정을 밝힐 수 있는 좋은 계기를 얻게 되었다. 본 조사에서 채집 동정된 해조류는 남조류 18종, 녹조류 13종, 갈조류 6종 그리고 홍조류 8종으로 총 45종이었다. 단위면적당 평균현존량은 교란 전에는 $53.50-188.00\;g-dry\;wt/m^2$ 이였고, 교란 후에도 $0.57-2.62\;g-dry\;wt/m^2$ 이였다. 우점종은 교란전에는 Polysiphonia morrowii와 Ceramium fastigiramosum의 2종이었고, 교란 후 초기 착생종으로 Lyngbya semiplena, Lyngbya lutea 및 Lyngbya rivulariarum 3종으로 대표됨이 밝혀졌다.

• 한국습지학회지
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• 제13권3호
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• pp.643-655
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• 2011

본 연구는 소양호 상류 유역의 지류 하천을 대상으로 부착조류의 생물학적 지수의 수질 대표성을 검토하였으며 총체적인 수질환경평가를 시도하였다. 북한강 상류의 4개 수계에 대한 하천(북천-한계천, 내린천, 인북천, 소양강)에서 배수구역을 중심으로 총 9개 지점을 조사 지점으로 선정하여 현장조사를 하였다. 하천 주변의 토지 이용은 농경지중심과 임야 중심으로 뚜렷한 분포차이를 보였고, 소양강 상류 하천 유역은, 농경지 중심 지역에서는 오염된 수역의 대표종인 남조강이 높은 출현률을 보였고, 임야 중심 지역에서는 남조강, 녹조강, 규조강이 비교적 고르게 출현하였다. 따라서 오염원의 분포와 부착조류의 현존량 및 군집 분포는 밀접한 연관이 있으며, BOD, SS 그리고 종다양도, 균등도의 생물지수들은 조사지점 대부분에서 유사한 값을 보였으며, 국내 하천에서 소양강 상류 하천 조사 지점의 하천 수질에 대해 전체적으로 빈부수성이며 양호하다는 단편적인 결과를 나타내었다. 따라서 하천수질과 영양 상태에 대한 평가에 사용되는 기존 생물지수 및 하천등급판정기준은 수체 내 영양염류에 민감하여 부영양화 판정에 효과적인 부착조류의 생지화학적 특성을 충분히 활용하지 못하였다.

• Fisheries and Aquatic Sciences
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• 제23권6호
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• pp.15.1-15.14
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• 2020

Background: Large rivers are ecological treasures with high human value, but most have experienced decades of degradation from industrial and municipal sewage, row-crop agricultural practices, and hydrologic alteration. We reviewed published analyses of long-term fish diversity publications from three intensively managed large river ecosystems to demonstrate the conservation potential of large river ecosystems. Results: We show how the incorporation of recent advances in river concepts will allow a better understanding of river ecosystem functioning and conservation. Lastly, we focus on the Wabash River ecosystem based on high conservation value and provide a list of actions to maintain and support the ecosystem. In the Wabash River, there were originally 66 species of freshwater mussels, but now only 30 species with reproducing populations remain. Although there were multiple stressors over the last century, the largest change in Wabash River fish biodiversity was associated with rapid increases in municipal nutrient loading and invasive bigheaded carps. Conclusions: Like similarly neglected large river systems worldwide, the Wabash River has a surprising amount of ecological resilience and recovery. For instance, of the 151 native fish species found in the 1800s, only three species have experienced local extinctions, making the modern assemblage more intact than many comparable rivers in the Mississippi River basin. However, not all the changes are positive or support the idea of recovery. Primary production underpins the productivity of these ecosystems, and the Wabash River phytoplankton assemblages shifted from high-quality green algae in the 1970s to lower less nutritional blue-green algae as nutrient and invasive species have recently increased. Our recommendations for the Wabash River and other altered rivers include the restoration of natural hydrology for the mainstem and tributaries, nutrient reductions, mechanisms to restore historical hydrologic patterns, additional sediment controls, and improved local hydraulics.

• 생태와환경
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• 제40권4호
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• pp.576-580
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• 2007

Phytoplankton community dynamics were studied from 2004 to 2006 with two and four weeks interval at mid to lower part of the Nakdong River (Waegwan: RK 194, Goryeong: RK 157, Jukpo: RK 112, Namji: RK 75 and Hanam: RK 63: RK: distance from the Estuarine Barrage), South Korea. Annual averages of water temperature was about $16^{\circ}C$, and dissolved oxygen was ranged between 10.0 and 11.5 mg $L^{-1}$ (percent saturation, 106.5 to 112.8%). Diatoms were dominant group with over 60% of phytoplankton abundance in all study sites (Waegwan: 64%, Goryeong: 69%, Jukpo: 73%, Namji: 79%, and Hanam: 83%). However, the occasional dominances of other groups such as green algae and blue-green algae were observed from March to October. Stephanodiscus hantzschii was dominant species and the relative abundances were highat all study sites (48-72%). The ratio of S. hantzschiiltotal phytoplankton abundance were showed a clear increasing tendency toward the estuarine barrage: i.e. 0.31 at Waegwan, 0.39: Goryeong, 0.50: Jukpo, 0.56: Namji, 0.60: Hanam. The results of this study provide the information that the phytoplankton community structure in a regulated river system is basically affected by the physical properties such as water velocity and retention time, resulting in single species dominance by the stagnancy of river flow.

• Journal of Microbiology and Biotechnology
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• 제25권1호
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• pp.109-118
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• 2015

Open raceway ponds are cost-efficient for mass cultivation of microalgae compared with photobioreactors. Although low-cost options like wastewater as nutrient source is studied to overcome the commercialization threshold for biodiesel production from microalgae, a cost analysis on the use of wastewater and other incremental increases in productivity has not been elucidated. We determined the effect of using wastewater and wavelength filters on microalgal productivity. Experimental results were then fitted into a model, and cost analysis was performed in comparison with control raceways. Three different microalgal strains, Chlorella vulgaris AG10032, Chlorella sp. JK2, and Scenedesmus sp. JK10, were tested for nutrient removal under different light wavelengths (blue, green, red, and white) using filters in batch cultivation. Blue wavelength showed an average of 27% higher nutrient removal and at least 42% higher chemical oxygen demand removal compared with white light. Naturally, the specific growth rate of microalgae cultivated under blue wavelength was on average 10.8% higher than white wavelength. Similarly, lipid productivity was highest in blue wavelength, at least 46.8% higher than white wavelength, whereas FAME composition revealed a mild increase in oleic and palmitic acid levels. Cost analysis reveals that raceways treating wastewater and using monochromatic wavelength would decrease costs from 2.71 to 0.73 $/kg biomass. We prove that increasing both biomass and lipid productivity is possible through cost-effective approaches, thereby accelerating the commercialization of low-value products from microalgae, like biodiesel.

• 한국문화재보존과학회:학술대회논문집
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• 한국문화재보존과학회 2005년도 제22회 학술대회 발표 논문집
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• pp.100-103
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• 2005

Lichens play an important role in breaking down rocks physically and chemically. Physical weathering occurs mechanically through hyphae and rhizines growing into the rocks. Lichen substances such as oxalic acid, acidic polysaccharides and depsides may assist altering rocks chemically. These actions partly contribute to soil formation but prove harmful for the substratum. Some people do not like to keep lichens on stained glassof churches or on gravestones mainly because of its unglamorous appearance. A biocide, 'Koretrel', is very effective in removing lichens and blue-green algae from the surface of concrete. After spraying 'Koretrel' in the open air, lichens (Caloplaca sp., Endocarpon petrolepideum, Physciella melanchra, Phaeophyscia hispidula, etc.) growing on buildings died within three months and peeled off fromthe substratum. One year after treatment, concrete surfaces were almost lichen free for three or four years. The biocide makesuse of a kind of lichen substance and harmless both for substances and environment. Our recent experiments show that it is also useful for water grasses growing on the surface of an aqueduct of a hydroelectric power station.

• Journal of Microbiology and Biotechnology
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• 제18권10호
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• pp.1655-1658
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• 2008

Cyanobacteria, blue-green algae, are a rich source of bioactive secondary metabolites with many potential applications. The ubiquitin-proteasome proteolytic system plays an important role in selective protein degradation and regulates cellular events including apoptosis. Cancer cells are more sensitive to the proapoptotic effects of proteasome inhibition than normal cells. Thus, proteasome inhibitors can be potential anticancer agents. Cyanobacteria have been shown to be a rich source of highly effective inhibitors of proteases. A proteasome inhibitor was screened from an extract of the culture of Scytonema hofmanni on the basis of its inhibitory activity, which led to the isolation of nostodione A with an $IC_{50}$ value of 50${\mu}M$. Its structure was determined by spectroscopic methods such as $^{1}H$-NMR and ESI-MS spectral analyses.