• Biotechnology and Bioprocess Engineering:BBE
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• 제8권6호
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• pp.322-330
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• 2003

The unicellular green alga Haematococcus pluvialis has recently attracted great inter-est due to its large amounts of ketocarotenoid astaxanthin, 3,3'-dihydroxy-${\beta}$,${\beta}$-carotene-4,4'-dione, widely used commercially as a source of pigment for aquaculture. In the life cycle of H. pluvialis, astaxanthin biosynthesis is associated with a remarkable morphological change from green motile vegetative cells into red immotile cyst cells as the resting stage. In recent years we have studied this morphological process from two aspects: defining conditions governing astaxanthin biosynthesis and questioning the possible function of astaxanthin in protecting algal cells against environmental stress. Astaxanthin accumulation in cysts was induced by a variety of environmental conditions of oxidative stress caused by reactive oxygen species, intense light, drought, high salinity, and high temperature. In the adaptation to stress, abscisic acid induced by reactive oxygen species, would function as a hormone in algal morphogenesis from veget ative to cyst cells. Furthermore, measurements of both in vitro and in vivo antioxidative activities of astaxanthin clearly demonstrated that tolerance to excessive reactive oxygen species is greater in astaxanthin-rich cysts than in astaxanthin-poor cysts or astaxanthin-less vegetative cells. Therefore, reactive oxygen species are involved in the regulation of both algal morph O-genesis and carotenogenesis, and the accumulated astaxanthin in cysts can function as a protective agent against oxidative stress damage. In this study, the physiological roles of astaxanthin in stress response and cell protection are reviewed.

• Journal of Plant Biology
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• 제15권1호
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• pp.13-22
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• 1972

In the present paper, seven marine algae collected from the coasts of Korea are described. The two blue-green algae, Coccochloris stagnina Sprengel and Entophysalis conferta (Kuetz.) Drouet and Daily, one brown alga, Ralfsia verrucosa(Aresch.) J. Ag., and the two red algae, Enelittosiphonia hakodatensis (Yendo) Segi and Symphyocladia pennata Okamura, are recorded newly in our country. The other two blue-green algae, Anacystis dimidiata (Kuetz.) Drouet and Daily and Phormidium tenue (Meneghini) Gomont, are recorded for the first time marine water in our country.

• 한국동물학회:학술대회논문집
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• 한국동물학회 2000년도 한국생물과학협회 학술발표대회
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• pp.200.1-200
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• 2000

No Abstract, See Full Text

• 한국식물학회:학술대회논문집
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• 한국식물학회 2000년도 춘계학술발표대회:발표눈문요지록
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• pp.26-26
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• 2000

• 환경생물
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• 제42권1호
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• pp.127-134
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• 2024

2022년 11월 전남 해남 송지해변에서 녹조류의 대량발생이 일어났다. 해변에서는 악취가 발생하였고, 녹조류가 녹색의 두꺼운 매트처럼 해변을 넓게 덮고 있었다. 종동정 결과는 범세계분포종인 녹조류 참깃털말로 나타났다. 참깃털말의 대량발생이 일어난 송지해변과 인근 지역의 해수 중 영양염 농도를 비교한 결과, 용존무기질소와 용존무기인 농도는 각각 1.067 및 0.461 mg L^-1로 남서해안 평균 영양염에 비해 6배 및 19배 높게 나타났다. 이 연구에서는 국내에서 처음으로 나타난 참깃털말의 대량발생 양상에 대하여 보고하였으며, 이는 해수 중 영양염 농도와 밀접한 관계가 있는 것으로 나타났다. 따라서 참깃털말 등의 녹조류 대량발생을 제어하기 위해서는 연안으로 유입되는 육상의 영양염 농도에 대한 관리가 필요할 것으로 사료된다.

• ALGAE
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• 제31권4호
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• pp.363-371
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• 2016

To examine the effects of two endophytic algae, Mikrosyphar zosterae (brown alga) and Ulvella ramosa (green alga), on the host Chondrus ocellatus (red alga), culture experiments were conducted. Four treatments were made: endophyte-free (Chondrus only), endophyte-M (Chondrus + Mikrosyphar), endophyte-U (Chondrus + Ulvella), and endophytes-M U (Chondrus + Mikrosyphar + Ulvella). After 3 weeks, the relative growth rates (RGRs) of frond lengths and the number of newly formed bladelets were examined. M. zosterae formed wart-like dots on C. ocellatus fronds, whereas U. ramosa made dark spots. The RGRs of frond lengths of C. ocellatus were significantly greater in the endophyte-free and endophyte-M treatment groups than in the endophyte-U and endophytes-M U treatment groups, indicating that the growth of host C. ocellatus was inhibited more by the green endophyte U. ramosa than the brown endophyte M. zosterae. The number of newly produced bladelets was greater in the endophyte-U and endophytes-M U groups than in the endophyte-free and endophyte-M treatment groups. These results indicate that the two endophytes inhibit growth of the host C. ocellatus. The negative effects of U. ramosa on C. ocellatus growth were more severe than those caused by M. zosterae. Furthermore, U. ramosa destroyed the apical meristems of C. ocellatus, whereas M. zosterae did not. On the other hand, C. ocellatus showed compensatory growth in the form of lateral branch production as U. ramosa attacked its apical meristems.

• Journal of Microbiology and Biotechnology
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• 제10권3호
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• pp.300-306
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• 2000

The rate of apparent nitric oxide (NO) release, as measured in the exhaust gas of green alga, Scenedesmus obliquus, depended on the light intensity and pH. It doubled after lowering the temperature from $25^{\circ}C{\;}to{\;}15^{\circ}C$ and strongly decreased from $35^{\circ}C{\;}to{\;}42^{\circ}C$. The Scenedesmus cells, deficient in nitrogen or phosphorus, demonstrated a significant increase in NO production following their transfer to nitrate- and phosphate-rich media. The addition of herbicides (DCMU and glyphosate) or toxic concentrations of $Cu^{2+}{\;}or{\;}Fe^{3+}$ produced strong NO peaks, resembling those that occurred after sudden darkening. An increase in the $Ni^{2+}$ concentration to 20 ppm resulted in a gradual increase of NO release from the initial ~1.5 ppbv to>20 ppbv, whereas $Cd^{2+}$ instantaneously suppressed the NO by the cultures of Scenedesmus was not altered by L-NNA, an inhibitor of nitric oxide synthase (NOS), or by its substrate, L-arginine. This seems to exclude the role of NOS in the NO formation under study. Accordingly, it can be assumed that the rate of NO formation is mainly a function of dynamic nitrite pool sizes and environmental factors significantly affect the NO production in algae.

• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1333-1341
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• 2009

Haematococcus pluvial is, a green alga, accumulates astaxanthin (3,3'-dihydroxy-$\beta$,$\beta$'-carotene-4,4'-dione) upto 2-3% on a dry weight basis. In the present study, identification of carotenoids from Haematococcus cyst cell extract by HPLC and LC-MS (APCI) and their antioxidant properties were evaluated in in vitro model systems. The extract exhibited 89% and 78% antioxidant activities in the $\beta$-carotene linoleate model and the hydroxyl radical scavenging model, at 9 ppm of total carotenoid, respectively. The extract also showed 80%, 85%, and 79% antioxidant activities against lipid peroxidation in the kidney, brain, and liver of rats. Low-density lipoprotein oxidation induced by $Cu^{2+}$ ions was also protected (45%, 64%, and 75%) by the extract in a dose-dependent manner with different carotenoid levels. Thiobarbituric acid reactive substances concentration in the blood, liver, and kidney of rats were also significantly (p<0.005) decreased in H. pluvialis-treated rats. The potent antioxidant activity is attributable to various carotenoids present in the extract.

• 공업화학
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• 제33권2호
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• pp.222-228
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• 2022

As a possible feedstock for biodiesel, the marine green alga Tetraselmis sp. was cultivated under different conditions of phototrophic, mixotrophic and heterotrophic cultures. Glycerol, a byproduct from biodiesel production process, was used as the carbon source of mixotrophic and heterotrophic culture. The effects of glycerol supply and nitrate-repletion were compared for different trophic conditions. Mixotrophic cultivation exhibited higher biomass productivity than that of phototrophic and heterotrophic cultivation. Maximum lipid productivity of 55.5 mg L^-1 d^-1 was obtained in the mixotrophic culture with 5 g L^-1 of glycerol and 8.8 mM of nitrate due to the enhancement of both biomass and lipid accumulation. The major fatty acid methyl esters (FAME) in the produced biodiesel were palmitic acid (C16:0), oleic acid (C18:1), linoleic acid (C18:2), and linolenic acid (C18:3). The degree of unsaturation was affected by different culture conditions. The biodiesel properties predicted by correlation equations based on the FAME profiles mostly complied with the specifications from the US, Europe and Korea, with the exception of the cold-filter plugging point (CFPP) criterion of Korea.

• 생태와환경
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• 제40권4호
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• pp.537-545
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• 2007

The heavy metal removal capacity of filamentous green alga Cladophora sp. cultured together with wet-mixed solidified soil (loess) was tested. A Cladophora sp. was cultured for 5d, with added Chu No. 10 medium, in stream water contaminated by high concentration of heavy metals from a closed mine effluent. Heavy metal ion concentrations of the medium and in algal tissue were measured every day during the experiment. Dissolved metals (Al, Cd, Cu, Fe, Mn, Zn) in medium were rapidly removed (over 90% elimination) within 1-2d when alga and loess were added. Dissolved heavy metals dropped by only 10% when algae were cultured without loess. The Cladophora sp. accumulated much more heavy metals when cultured with loess than when the alga was cultured alone. Cladophora sp. exhibited a maximum uptake capacity for Al ($17,000{\mu}g^{-1}$ algal dry weight). The metal bioremoval capacities of the algae were in the order Al, Fe, Cu, Mn, Zn and Cd. The heavy metal removal capacity of Cladophora sp. showed significant increases when wet-mixed solidified soil was added to culture media.