• Natural Product Sciences
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• v.8 no.3
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• pp.103-107
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• 2002

Four known sesquiterpenes, laurinterol (1), isolaurinterol (2), aplysinal (3) and aplysin (4) were isolated from the Korean red alga Laurencia okamurae off Cheju Island, Korea. Their structures were identified by comparison with the literature data. Compounds 1-4 showed potent cytotoxicity against A549, SK-OV-3, SKMEL-2, XF498, and HTl5 cell lines with $EC_{50}$ values ranging from 1.2 to 17.6 ${\mu}g/ml$.

• Korean Journal of Environmental Agriculture
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• v.29 no.2
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• pp.184-188
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• 2010

A cyanobacteria species, Anabaena sp. PCC 7120, was tested to assess its biotransformation ability on two widely used insecticides, aldrin and chlorpyrifos-methyl, in the culture medium. The blue-green alga metabolized aldrin mainly to dieldrin by an epoxidation reaction with the participation of cytochrome P450-dependent monooxygenase in the cyanobacteria. The blue-green alga also produced chlorpyrifosmethyl oxon as a primary metabolite from chlorpyrifos-methyl via a desulfuration reaction, presumably conducted by cytochrome P450-dependent monooxygenase. Therefore, two insecticides might be possibly dissipated by cytochrome P450-dependent monooxygenases in the blue-green algae in the contaminated environments.

• Korean Journal of Environmental Biology
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• v.37 no.3
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• pp.293-298
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• 2019

A marine ulvalean species (Chlorophyta) was collected from the eastern coast of Korea. This species is morphologically characterized by a distromatic, dark to medium green and mostly irregularly orbicular or irregularly expanded thallus with entire or undulate margin without serrations. Vegetative cells are irregularly polygonal with distinctly rounded corners in shape, and have chloroplast completely covering the outer cell wall and one to two pyrenoids per cell. In a phylogenetic tree based on ITS (Internal Transcribed Spacer) sequences, this Korean alga nests in the same clade with Ulva sublittoralis, as a sister clade of U. californica, U. flexuosa and U. tanneri, which share the irregularly orbicular or expanded thallus normally without teeth cells. The genetic divergence between them is intraspecific within Ulva. Accordingly, it is identified as U. sublittoralis based on the morphological and molecular data. This is the first record of Ulva sublittoralis in the Korean marine algal flora.

• Fisheries and Aquatic Sciences
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• v.12 no.2
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• pp.86-89
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• 2009

2,3,6-Tribromo-4,5-dihydroxybenzyl methyl ether (TDB) from the methanolic extract of the red alga Symphyocladia latiuscula exhibits major antioxidant activity. In this study, the activity of TDB against oxidative damage in deoxyribose and DNA was investigated in vitro for potential applications in preventing mutagenesis caused by DNA damage. TDB inhibited the oxidation of deoxyribose at concentrations of up to $1{\mu}g$/mL in the presence of $Fe^{+3}$-EDTA/$H_2O_2$. Furthermore, TDB showed no pro oxidant activity as determined by absence of the reduction of bleomycin-$Fe^{+3}$ to bleomycin-$Fe^{+2}$, which leads to DNA damage. Based on these results, TDB demonstrated considerable antioxidant activity without prooxidant properties.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.745-751
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• 2015

The ecological characteristics of Silvetia siliquosa, an endangered brown alga, were investigated from January to December 2013 in Jindo, South Korea. The S. siliquosa population formed widespread patches on natural rock. Receptacles were observed from March to August when seawater temperatures ranged from 8-26℃. A maturation peak was detected in June, when seawater temperatures were 23.4℃. After embryo release, the alga bleached and only the discoidal holdfast remained after August. Developmental initiation of the thallus occurred at temperatures above 8℃, and receptacle formation required approximately 196 degree-days. This is the first study to examine a S. siliquosa population throughout the entire year in a natural habitat.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.1
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• pp.77-82
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• 2013

Phyllodictyon anastomosans (Harvey) Kraft et M.J. Wynne and Saccharina ochotensis (Miyabe) E.E. Lane C. Mayes, Druehl et G.W. Saunders are first recorded in Korea. A pantropical green alga, P. anastomosans was collected on a rock wall in the subtital zone of Jeju Island. This species has very tiny fan-shaped and netted thalli that are green in color. A cold temperate brown alga, P. ochotensis has very thick and leathery thalli that are deep brown in color. Morphological characteistics and habitats of these species are described with taxonomic accounts.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.5
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• pp.509-520
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• 1992

AIGaAs /GaAs HBT OR /NOR gate. which can be used for high speed digital system was designed. Equivalent circuit parameters of HBT were obtained from Gummel-Poon's model and direct extraction method. Simulation results with PSPI CE showed that propagation delay time and cutoff toggle frequency of designed gate were 25ps and 200Hz, respectively. the designed gate exhibited superior properties to the recently reported HBT ECL and MESFET SCFL when considering the fan-out characteristics and noise margin.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.11a
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• pp.198-200
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• 2001

Grager-Induced colony formation was examined using strains of green alga Scenedemus dimorphus (Turpin) Kutzing. Alga was cultured in a medium with or without filtered water in which Daphnia magna or Moina macrocopa had been reared. Colony formation was obviously promoted in S. dimorphus by exposure to zooplankton filtered water (ZFW), showing in proportion to the volume of zooplankton filtered water in cultured media. The particle volume as well as the number of cells per one colony of S. dimorphus increased between 24 and 48 hours after exposure to ZFW, which were caused by an infochemical released from from Daphnia or Moina probably as a part of defense mechanism against zooplankton grazing.

• ALGAE
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• v.22 no.2
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• pp.125-129
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• 2007

Conventional methods for the isolation and purification of mRNA from Zygnema were unsuccessful because of its high amount of pigments and RNA interactive molecules. In particular, pigments were difficult to remove using conventional protocols because they interacted with RNA during pulverization of the materials. This resulted in total degeneration of RNA in two to three hours. To alleviate this problem, we developed an isolation method that utilized DEAE-cellulose resin. The pigments bound to DEAE anion exchange resin and separated from the RNA. Purified total RNA showed an yield of 50 μg per 100 mg of tissue with this method. The amplified 2nd strand cDNA was distributed 300 bp and over.

• ALGAE
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• v.22 no.2
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• pp.87-93
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• 2007

Three ecotypes of the freshwater red alga Compsopogon coeruleus (Balbis) Montagne were recorded from different freshwater and brackish water habitats of Orissa state in the east coast of India. These three had persistent differences in their branching pattern, e.g. (i) acute angle between main axis and lateral branch, (ii) equal or near to right angle between main axis and lateral branch, and (iii) short spine-like outgrowth instead of a branch in older filaments, besides having differences in the length, breadth and thickness of cortex of the thallus. Morphological observation of these taxa, and the ecological characteristics of the habitat of their occurrence is presented.