• Proceedings of the PSK Conference
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• 2002.04a
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• pp.192.3-193
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• 2002

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.6
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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 Microbiology and Biotechnology
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• v.10 no.3
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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.

• ALGAE
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• v.25 no.4
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• pp.197-204
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• 2010

Cytoskeletal changes were observed during cell division of the green alga Zygnema cruciatum using flourescein isothiocynate (FITC)-conjugated phallacidin for F-actin staining and FITC-anti-$\alpha$-tubulin for microtubule staining. Z. cruciatum was uninucleate with two star-shaped chloroplasts. Nuclear division and cell plate formation occurred prior to chloroplast division. Actin filaments appeared on the chromosome and nuclear surface during prophase, and the F-actin ring appeared as the cleavage furrow developed. FITC-phallacidin revealed that actin filaments were attached to the chromosomes during metaphase. The F-actin ring disappeared at late metaphase. At telophase, FITC-phallacidin staining of actin filaments disappeared. FITC-anti-$\alpha$-tubulin staining revealed that microtubules were arranged beneath the protoplasm during interphase and then localized on the nuclear region at prophase, and that the mitotic spindle was formed during metaphase. The microtubules appeared between dividing chloroplasts. The results indicate that a coordination of actin filaments and microtubules might be necessary for nuclear division and chromosome movement in Z. cruciatum.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1245-1253
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• 2014

One-step sulfuric acid saccharification of the red alga Pterocladiella capillacea was optimized, and various detoxification methods (neutralization, overliming, and electrodialysis) of the acid hydrolysate were evaluated for fermentation with the thermotolerant yeast Kluyveromyces marxianus. A proximate composition analysis indicated that P. capillacea was rich in carbohydrates. A significant galactose recovery of $81.1{\pm}5%$ was also achieved under the conditions of a 12% (w/v) biomass load, 5% (v/v) sulfuric acid, $121^{\circ}C$, and hydrolysis for 30 min. Among the various detoxification methods, electrodialysis was identified as the most suitable for fermentable sugar recovery and organic acid removal (100% reduction of formic and levulinic acids), even though it failed to reduce the amount of the inhibitor 5-HMF. As a result, K. marxianus fermentation with the electrodialyzed acid hydrolysate of P. capillacea resulted in the best ethanol levels and fermentation efficiency.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.10
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• pp.4311-4317
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• 2014

Background: Nano-biotechnology is recognized as offering revolutionary changes in the field of cancer therapy and biologically synthesized gold nanoparticles are known to have a wide range of medical applications. Materials and Methods: Gold nanoparticles (GNPs) were biosynthesized with an aqueous extract of the red alga Corallina officinalis, used as a reducing and stabilizing agent. GNPs were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), energy dispersive analysis (EDX) and Fourier transform infra-red (FT-IR) spectroscopy and tested for cytotoxic activity against human breast cancer (MCF-7) cells cultured in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum, considering their cytotoxicty and effects on cellular DNA. Results: The biosynthesized GNPs were $14.6{\pm}1nm$ in diameter. FT-IR analysis showed that the hydroxyl functional group from polyphenols and carbonyl group from proteins could assist in formation and stabilization. The GNPs showed potent cytotoxic activity against MCF-7 cells, causing necrosis at high concentrations while lower concentrations were without effect as indicated by DNA fragmentation assay. Conclusions: The antitumor activity of the biosynthesized GNPs from the red alga Corallina officinalis against human breast cancer cells may be due to the cytotoxic effects of the gold nanoparticles and the polyphenolcontent of the algal extract.

• Preventive Nutrition and Food Science
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• v.12 no.2
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• pp.65-73
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• 2007

Sargassum fulvellum, a marine brown alga, is a popular low priced edible plant in Korean markets. The polysaccharide fraction of the alga was separated and investigated for its radical scavenging activities and the results compared with those of commercial fucoidans (Fucus vesiculosus and Undaria pinnatifida), BHA and ${\alpha}$-tocopherol. The polysaccharide fraction of S. fulvellum showed a promising DPPH radical scavenging activity than did other fucoidans. Moreover, the sample exhibited a dose-dependent activity on hydrogen peroxide scavenging activity in the V79-4 cell line. Interestingly, all the tested polysaccharide counterparts were more potent NO. scavengers than were the commercial antioxidants, BHA and ${\alpha}$-tocopherol. The sulfated polysaccharide of S. fulvellum had an approximate molecular weight of 529 kDa and mainly consisted of fucose and galactose, and minor amounts of mannose, rhamnose and xylose.

• ALGAE
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• v.22 no.1
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• pp.17-21
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• 2007

Sargassum filicinum Harvey, a brown alga (Phaeophyceae) native to Northeastern Asia, has been recently reported from the coast of Southern California (USA). Here we report the occurrence and range extension of this introduced species, as we found the alga at La Jolla and Rancho Packard in Todos Santos Bay, Baja California, Mexico. The first collections of S. filicinum correspond to several immature plants, found on September 8, 2005, drifting in the intertidal zone at La Jolla. Later on November 9, 2006, we found a well-established population in Rancho Packard in the middle intertidal zone to 2 m depth. Since S. filicinum is an annual monoecious species with air bladders, the risk there is a high risk of spreading rapidly along the Pacific, as in the case for S. muticum. The population in Rancho Packard extends 500 m along the coast, consisting mainly of young plants with an average length of 30 cm and a density of 5 thallus/m2. This is the first record of this invasive species for the Mexican Pacific coast, and it represents the southern limit along the Pacific coast of North America. This finding suggests that this invasive species has successfully colonized the Pacific coast of North America and its distributional range is still expanding.

• ALGAE
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• v.18 no.3
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• pp.191-197
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• 2003

Histones are important proteins that interact with the DNA double helix to form nucleosome. Two putative histone genes, GjH2A-1 and GjH2A-2 were isolated from a red alga Griffithsia japonica. The putative open reading frame of GjH2A-1 and GjH2A-2 shared high similarity with the previously reported amino acid sequences of histone H2As. They have a motif consisting of seven amino acids A-G-L-Q-F-P-V, which matches the histone H2A motif [AC]-G-L-x-F-P-V. Phylogenetic trees were constructed from amino acid sequences of 38 histone H2As. The histone H2As were divided into two groups: major H2As and H2A.F/Z variants. The major histone H2A group consisted of animals, fungi, plants + green algae, and red algae H2A subgroups. The animal histone H2A subgroup was divided into vertebrates, echinoderms, nematodes, insects, and segmented worms H2As. The putative red algal histone genes, GjH2A-1 and GjH2A-2, constituted an independent lineage. This is the first report on red algal histone genes.

• ALGAE
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• v.22 no.2
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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.