• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.211-216
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• 2001

The growth of Selenastrum capricornutum in culture was investigated as a function of ionic copper concentrations to verify the toxicity and physiological variation. In a $Cu^{++}$ excess culture (E: $Cu^{++}$ of $130{\mu}g/l$), the growth rate (K)(0.32) was lower than that of the control culture (C: $Cu^{++}$ of $0.065{\mu}g/l$) (0.61) after 8 days and the exponential growth rate ($R_E$) was also found to be lower in culture E (1.1) than culture C (2.9). On the contrary, the K of S. capricornutum in trace $Cu^{++}$ culture ($T_1$ and $T_2$, 0.72) after 6 days tended to be more increased than culture C (0.68). From 8 to 14 days of culture, the amounts of chlorophyllls a and b were increased in culture C (chlorophyll a, $106->126{\mu}g/g$ dry wt; chlorophyll b, $158->208{\mu}g/g$ dry wt; chlorophyll b were decreased in culture E (chlorophyll a, $309->235{\mu}g/g$ dry wt; chlorophyll b, $405->352{\mu}g/g$ dry wt). The amounts of chlorophylls in ionic copper trace culture ($T_1$ and $T_2$) [(chl a/b) of $T_1$: $384/620\;{\mu}g/g$ dry wt; (chl a/b) of $T^2$:$320/467{\mu}g/g$ dry wt] were increased more than the culture C($260/387{\mu}g/g$ dry wt). Howeveer, when photosynthetic rates were normalized to the dry weight of algae, the control culture continued to showed higher values than the treated culture ($T_1$). An appropriate amount of ionic copper ($T_1:\;26\;{\mu}g/l$) stimulated the grwoth of S. capricornutum than the ionic copper content of $13\;{\mu}g/l$ ($T_2$), while the excess amount of ionic copper ($130\;{\mu}g/l$) resulted in the highest toxicity to the growth of S. capricornutum.

• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.122-128
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• 1998

Characteristic changes in chlorophyll fluorescence from thalli of red alga, Porphyra, under high salt stress and during subsequent recovery were investigated, and the differences in the sensitivity to the stress among four species of Porphyra with different intertidal distributions were compared. By the treatment of NaCl with $9\%$ or higher concentrations, photochemical efficiency (Fv/Fm) decreased in a biphasic pattern: a rapid decrease was observed within 1­3 h and followed by a slow decline. The decrease of Fv/Fm was mainly due to the increase of Fo without significant increases of Fm. When the thalli treated with $15\%$ NaCl for 6 h were returned to natural sea water for recovery, the increase of Fv/Fm also showed a biphasic pattern: a rapid increase of Fv/Fm was observed within 2 h and followed by a slow increase. Differences in the sensitivity to salt stress among the four species could be found during recovery after the treatment of severe salt stress. After the treatment of $20\%$ NaCl for 6 h, Fv/Fm decreased below 0.3 in all of the four Porphyra species, and the species living in upper parts of the intertidal zone (P. suborbiculata and P. pseudolinearis) could recover better compared with the species in lower parts of the intertidal zone (P. seriata and P. yezoensis), during recovery for 24 h. The species collected from the coast of the South Sea seemed to be more tolerant than those in the East Sea.

• Biomolecules & Therapeutics
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• v.24 no.6
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• pp.650-658
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• 2016

Chronic alcohol consumption causes alcoholic liver disease, which is associated with the initiation of dysregulated lipid metabolism. Recent evidences suggest that dysregulated cholesterol metabolism plays an important role in the pathogenesis of alcoholic fatty liver disease. Ecklonia stolonifera (ES), a perennial brown marine alga that belongs to the family Laminariaceae, is rich in phlorotannins. Many studies have indicated that ES has extensive pharmacological effects, such as antioxidative, hepatoprotective, and antiinflammatory effects. However, only a few studies have investigated the protective effect of ES in alcoholic fatty liver. Male Sprague-Dawley rats were randomly divided into normal diet (ND) (fed a normal diet for 10 weeks) and ethanol diet (ED) groups. Rats in the ED group were fed a Lieber-DeCarli liquid diet (containing 5% ethanol) for 10 weeks and administered ES extract (50, 100, or 200 mg/kg/day), silymarin (100 mg/kg/day), or no treatment for 4 weeks. Each treatment group comprised of eight rats. The supplementation with ES resulted in decreased serum levels of triglycerides (TGs), total cholesterol, alanine aminotransferase, and aspartate aminotransferase. In addition, there were decreases in hepatic lipid and malondialdehyde levels. Changes in liver histology, as analyzed by Oil Red O staining, showed that the ES treatment suppressed adipogenesis. In addition, the ES treatment increased the expression of fatty acid oxidation-related genes (e.g., PPAR-${\alpha}$ and CPT-1) but decreased the expression of SREBP 1, which is a TG synthesis-related gene. These results suggest that ES extract may be useful in preventing fatty acid oxidation and reducing lipogenesis in ethanol-induced fatty liver.

• ALGAE
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• v.31 no.2
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• pp.167-174
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• 2016

Biological response of cells to variable conditions should affect the expression level of certain genes. Quantification of these changes in target genes needs stable internal controls. Real-time quantitative polymerase chain reaction (PCR) has traditionally used reference or ‘housekeeping’ genes, that are considered to maintain equal expression in different conditions, to evaluate changes in target genes between samples and experimental conditions. Recent studies showed that some housekeeping genes may vary considerably in certain biological samples. This has not been evaluated in red algae. In order to identify the optimal internal controls for real-time PCR, we studied the expression of eleven commonly used housekeeping genes; elongation factor 1-alpha, glyceraldehyde-3-phosphate dehydrogenase, β-actin, polyubiquitin, 30S ribosomal gene, 60S ribosomal gene, beta-tubulin, alpha-tubulin, translation initiation factor, ubiquitin-conjugating enzyme, and isocitrate dehydrogenase in different life-history stages of Bostrychia moritziana. Our results suggest that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and 30S ribosomal gene, have the most stable gene expression levels between the different life history stages (male, female, carposporophyte, and tetrasporophyte), while the other genes are not satisfactory as internal controls. These results suggest that the combinations of GAPDH and 30S would be useful as internal controls to assess expression level changes in genes that may control different physiological processes in this organism or that may change in different life history stages. These results may also be useful in other red algal systems.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.3
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• pp.262-277
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• 2018

We seasonally examined marine macroalgal community structures and ocean environmental characteristics in subtidal zones at five sites on and around Jeju Island, Korea, from February 2013 to November 2015. A total of 186 macroalgal species were identified, including 18 green, 33 brown, and 135 red algae. During the study period, the number of species was highest at Gapado Island (125 species) followed by Bukchon (123 species), Sagye (122 species), Sinheung (122 species) and Sinchang (97 species). Ecklonia cava, Peyssonnelia caulifera, Synarthrophyton chejuense, Corallina aberrans and Corallina crassisima occurred at all study sites and in all seasons. The average annual biomass of seaweed was $1,125.10g\;wet\;wt./m^2$ and ranged from $899.77g/m^2$ at Sinheung to $1,452.00g/m^2$ at Gapado. A brown alga E. cava was the most dominant species, accounting for 49.84% ($560.78g/m^2$) of the total seaweed biomass. Subdominant species were C. aberrans and C. crassissima, comprising 6.83% ($76.79g/m^2$) and 5.98% ($67.28g/m^2$) of total biomass, respectively. Cluster analysis revealed three distinct groups: the Sagye/Sinheung group (group A), the Bukchon/Sinchang group (group B), and the Gapado group (group C), indicating significantdifferences in macroalgal communities between sites.

• ALGAE
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• v.35 no.2
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• pp.189-200
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• 2020

Pyropia yezoensis has been used as functional food in East Asia, especially in Korea and Japan, for more than five hundred years. This study aims to evaluate the antioxidant effect of polyphenols and proteins-rich extracts from P. yezoensis (PPPs) against 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced oxidative cell damage. Among six Korean local strains obtained from Jinhae (JiH), Haenam (HN), Jangheung (JaH), Jindo (JD), Wando (WD), and Sinan (SA) areas, the extracts of P. yezoensis from SA and JD are relatively higher in polyphenols and proteins contents. SA showed the lowest IC₅₀ scavenging activities against 1,1-diphenyl-2-picryl-hydrazyl and alkyl radicals and displayed protective effects against reactive oxygen species (ROS) in AAPH-induced Vero cells. Especially, the PPPs extracts from SA and JD showed protective activities against AAPH-induced apoptosis, as observed by nuclear staining with Hoechst 33342. Furthermore, in vivo studies of the SA extract in zebrafish showed significantly reduced ROS generation, lipid peroxidation, and cell damage. This is the first study, to our knowledge, to evaluate the antioxidant bioactivity of PPP in the Korean Peninsula using a zebrafish model. Due to SA and JD both located in the west coast of Korea, we deduced that the chemical content of the different PPP extracts was mildly influenced by their geographic location, and this alga has potential of protective activity against AAPH-induced ROS both in vitro and in vivo.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.3
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• pp.164-171
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• 2005

Codium fragile (Suringar) Hariot, an edible green alga is farmed in Korea by natural blooming zygotes attachment. Experiments were conducted to reveal the conditions for artificial seed production of C. fragile by sexual and asexual reproduction. Growth was compared between zygotes attachment (sexual reproduction) and isolated utricles with medullary filaments (asexual reproduction). Zygotes and isolated utricles with medullary filaments were cultured under different light conditions (10, 20, 40, 60 and $100\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and temperatures (5, 10, 15, 20 and $25^{\circ}C$) under 16:8LD. Maximum growth of zygote was $261.3{\pm}21.0\;{\mu}m$ under $15^{\circ}C$ and $20\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ after 13 days culture. Maximum regeneration of isolated medullary filament was $8.1{\pm}1.7\;mm$ per one isolated utricle under $20^{\circ}C$ and $100\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ after 15 days culture. After intermediate culture during two months in the field, morphogenesis occurred in both sexual and asexual reproduction, and growth of young thalli was not significantly different (p>0.05) between the both reproduction methods. Even though seed production of C. fragile is possible in both sexual and asexual reproduction, the mass artificial seed production of asexual reproduction is much more effective than that of sexual reproduction that is too much affected by maturity.

• Archives of Pharmacal Research
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• v.27 no.12
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• pp.1226-1232
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• 2004

Extracts from seventeen seaweeds were determined for tyrosinase inhibitory activity using mushroom tyrosinase with L-tyrosine as a substrate. Only one of them, Ecklonia stolonifera OKAMURA (Laminariaceae) belonging to brown algae, showed high tyrosinase inhibitory activity. Bioassay-guided fractionation of the active ethyl acetate (EtOAc) soluble fraction from the methanolic extract of E. stolonifera, led us to the isolation of phloroglucinol derivatives [phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5)]. Compounds 1~5 were found to inhibit the oxidation of L-tyrosine catalyzed by mushroom tyrosinase with $IC_{50}$ values of 92.8, 126, 33.2, 177, and 2.16 ${\mu}g$ /mL, respectively. It was compared with those of kojic acid and arbutin, well-known tyrosinase inhibitors, with $IC_{50}$ values of 6.32 and 112 ${\mu}g$ / mL, respectively. The inhibitory kinetics analyzed from Lineweaver-Burk plots, showed compounds 1 and 2 to be competitive inhibitors with $K_i$ of $2.3{\times}10^{-4}\;and\;3.1{times}10^{-4}$ M, and compounds 3~5 to be noncompetitive inhibitors with $K_i$ of $1.9{\times}10^{-5},\;1.4{\times}10^{-3}\;and\;1.5{\times}10^{-5}$ M, respectively. This work showed that phloroglucinol derivatives, natural compounds found in brown algae, could be involved in the control of pigmentation in plants and other organisms through inhibition of tyrosinase activity using L-tyrosine as a substrate.

• Preventive Nutrition and Food Science
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• v.17 no.2
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• pp.122-128
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• 2012

Gelidium (G.) elegans is a red alga inhabiting intertidal areas of North East Asia. We examined anti-oxidative and anti-inflammatory effects of G. elegans, depending on drying and extraction conditions, by determining reactive oxygen species (ROS) and nitric oxide (NO) in 3T3-L1 and RAW 264.7 cells. Extraction yields of samples using hot air drying (HD) and far-infrared ray drying (FID) were significantly higher than those using natural air drying (ND). The 70% ethanol extracts showed the highest total phenol and flavonoid contents compared to other extracts (0, 30, and 50% ethanol) under tested drying conditions. The scavenging activity on 2,2-diphenyl- 1-picrylhydrazyl (DPPH) and nitrite correlated with total phenol or flavonoid content in the extracts. The greatest DPPH scavenging effect was observed in 70% ethanol extract from FID and HD conditions. The production of ROS and NO in 3T3-L1 and macrophage cells greatly decreased with the 70% ethanol extraction derived from FID. This study suggests that 70% ethanol extraction of G. elegans dried by FID is the most optimal condition to obtain efficiently antioxidant compounds of G. elegans.

• ALGAE
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• v.29 no.2
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• pp.101-109
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• 2014

Small red algae, especially those previously referred to as 'primitive' are often overlooked, but can be quite abundant. These 'primitive' red algae are now placed in several classes distinct from the Florideophyceae, for example the Stylonematophyceae. A brownish-red filamentous alga was collected from a sandy tide pool at Cape Tribulation, Queensland, Australia. Cultured specimens were identified as Bangiopsis and conformed to the morphological characters of the genus (multicellular base, erect filaments branched or unbranched, uniseriate to multiseriate-tubular, single multilobed purple-red to red-brown plastid with central pyrenoid, vegetative cells released directly as spores). Molecular data of two plastid genes (rbcL, psbA) support placement of the Australian isolate and isolates from India in Bangiopsis. The genetic variation between these isolates and isolates from Puerto Rico previously attributed to B. subsimplex indicates that these should be considered as a separate species. As the type locality is in the Atlantic Ocean, French Guiana, and not far from Puerto Rico, and the Puerto Rican isolate has been used often in phylogenetic analyses, we propose that the Indian and Pacific Ocean isolates be designated a new species, B. franklynottii, to acknowledge Ott's many years of research on inconspicuous freshwater and marine red algae. Our research also highlights the lack of careful descriptions in many of the records of this genus and the lack of morphological characters to distinguish species. Especially within the morphologically simple red algae, morphological distinctness does not necessarily reflect evolutionary divergences.