• Journal of Marine Bioscience and Biotechnology
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• v.6 no.1
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• pp.31-40
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• 2014

The production of astaxanthin in the microalga Haematococcus pluvialis has been investigated using a sequential methodology based on the application of two types of statistical designs. The employed preliminary experiment was a fractional factorial design $2^6$ in which the factors studied were: excessive irradiance and nitrate starvation, phosphate deficiency, acetate supplementation, salt stress, and elevated temperature. The experimental results indicate that the amount of astaxanthin accumulation in the cells can be enhanced by excessive irradiance and nitrate starvation whereas the other factors tested did not yield any enhancement. In the subsequent experiment, a central composite design was applied with four variables, light intensity, nitrate, phosphate, and acetate, at five levels each. The optimal conditions for the highest astaxanthin production were found to be $1040{\mu}E/(m^2{\cdot}s)$ light intensity, 0.04 g/L nitrate, 0.31 g/L phosphate, 0.05 g/L acetate concentration.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.1
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• pp.80-83
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• 2006

Allergy, meaning 'heightened reactivity' of a host on being exposed to an antigen, is an immediate reaction which included anaphylaxis following contact with an antigen. An anaphylatic reaction is caused by the release of pharmacological mediators, like histamine, from mast cells. The potential anti-allergic activities of 27 seaweed and 19 salt marsh extracts collected from the coast of Korea were tested against the inhibition of histamine release in rat peritoneal mast cells (RPMCs). Among them, three salt marsh plants (Persicaria lapathifolia, Ixeris tamagawaensis, and Salsola komarovil) significantly showed more than 75% of inhibition of the histamine release at a concentration of $100{\mu}g/mL$, and also three salt marsh (Messerschmidia sibirica, Rosa rugosa, and Portulaca oleraceae) and three seaweed (Colpomenia bullosa, Derbesia marina, and Sargassum thunbergil) extracts exhibited moderately inhibition effects when compared to the control.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.356-366
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• 2021

Two marine actinobacterial isolates, RG3 and RG8, were identified using 16Sr DNA as Streptomyces althioticus RG3 and Streptomyces californicus RG8 and submitted to the database of genetic information with accession numbers MW661230 and MW661234, respectively; they were found to have emulsification indexes of 60 ± 2.5% and 53 ± 2.2%, respectively. The biosurfactants obtained were stable at a temperature of 35℃ for both strains; they were stable at 10% NaCl, in the case of S. althioticus RG3 and at 10-15% NaCl in the case of Str.californicus RG8; both strains produced the most biosurfactant when exposed to alkaline conditions. We characterized the biosurfactants, including features such as their chemical composition, using Fourier transform infrared spectroscopy analysis. The antimicrobial activity of the biosurfactant extracts was evaluated using the well diffusion method against Vibrio alginolyticus MK170250, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 4027, and Staphylococcus aureus ATCC 25923. S. althioticus RG3 biosurfactants were found to have better antimicrobial activity than those of Str. californicus RG8, indicating that they may be used in pharmaceutical industries and in the manufacture of antifouling products.

• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.43-53
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• 2019

The anticancer activity of guava (Psidium guajava L.) leaf extract (GLE) occurs via the induction of apoptosis in cancer cells. However, the mechanism behind GLE-induced apoptosis in the human hepatocellular carcinoma cell line HepG2 remains unclear. In the present study, we investigated the apoptotic effects and mechanism of action of GLE in cultured HepG2 cells. The results showed that GLE induced reactive oxygen species (ROS) synthesis and disrupted the mitochondrial membrane potential (${\Delta}{\Psi}m$). Moreover, GLE increased the expression of apoptotic pathway proteins, such as the cleaved forms of caspase-3, -8, and -9; the translocation of Bax and cytochrome c (cyt-c) from the mitochondria to the cytosol; and the downregulation of Bcl-2. In addition, p53 protein expression was increased upon GLE treatment. These observations indicate that the GLE-induced apoptosis in HepG2 cells is mediated by mitochondrial ROS generation, followed by caspase activation and cyt-c release, suggesting that GLE may be a promising candidate for the development of novel drugs for the treatment of liver cancers.

• Journal of Marine Bioscience and Biotechnology
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• v.12 no.2
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• pp.91-98
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• 2020

Stichopus japonicas (red sea cucumbers) inhabit the coastal sea surrounding Jeju Island, South Korea, and are thought to have various medicinal properties. In this study, we investigated the anticancer activity of a red sea cucumber (S. japonicus) collected from Jeju Island. We obtained the red sea cucumber extract (RSCE), and observed that it inhibited the tumor cell growth and increased reactive oxygen species (ROS) production associated with the induction of apoptosis through the mitogen-activated protein kinase (MAPK) pathway in murine colon carcinoma cells (CT-26). Treatment with RSCE and N-acetylcysteine, which is a ROS scavenger, increased ROS production and apoptosis via the regulation by the MAPK pathway on the ERK and JNK compared with the nontreated group. Therefore, RSCE promotes ROS-mediated suppression of the ERK and JNK activation, and subsequently inhibits cancer progression, suggesting that RSCE may be beneficial in treating colon carcinoma.

• Journal of Marine Bioscience and Biotechnology
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• v.12 no.2
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• pp.115-122
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• 2020

Eisenia bicyclis, a perennial macroalga is a primary producer of in the ocean, It has been identified as a key species that plays a vital role in maintaining the ecosystem stability. Also, it is an important target in marine afforestation projects and useful marine organisms. In addition, E. bicyclis is used as a health food for humans. This study investigated the effect of water temperature, light (photon irradiance), and duration of light (photoperiod) on the growth of gametophytes and young sporophytes of E. bicyclis. The germination and growth of the zoospores of E. bicyclis were examined at five temperatures (5℃, 10℃, 15℃, 20℃ and 25℃), four intensities of photon irradiance (10, 20, 40, and 80 μmol m-2s-1), and photoperiods (14:10 and 10:14 light/dark cycles). The zoospores released from mature plant germinated into the gametophytes under all experimental conditions. The gametophytes were able to grow at water temperature 5℃-25℃ and mature at 10℃-20℃. The optimal range of water temperature for the maturation of the gametophyte was 15℃-20℃. At 25℃, E. bicyclis gametophytes grew rapidly but did not mature. The optimal culture conditions for the growth of young sporophytes grew slowly in low temperature and photon irradiances.

• Journal of Marine Bioscience and Biotechnology
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• v.14 no.1
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• pp.51-60
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• 2022

A green alga specimen was collected from the eastern coast of Korea. This species shared the typical features of genus Ulva and was characterized by irregularly shaped thalli, relatively small and thick thallus, entire undulate margins without serrations, and one or two pyrenoids per cell. In a phylogenetic tree, based on sequences of the nuclear-encoded internal transcribed spacer region, it nests as a sister clade to a few species including Ulva ohnoi, which has a relatively large thallus. This Korean algal specimen differs from the species forming the same subclades, including U. ohnoi, Ulva fasciata, Ulva reticulata, and Ulva gigantean, and has a relatively small (3-8 cm) and thick (60-100 ㎛) thallus. Of these species, U. ohnoi, originally described from Japan, is similar to the Korean alga as it had a thick thallus of 30-90 ㎛, but it has microscopic serrations on the thallus margin, unlike the Korean alga. The genetic distance between the Korean alga species and the aforementioned species was determined to be 1.8%-4.8%, indicating an inter-specific divergence level at the genus Ulva. Herein, Ulva grossa sp. nov. (Ulvales, Chlorophyta) from Korea is described based on the morphological and molecular analyses.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.1
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• pp.60-67
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• 2007

For the first time in Vietnam, morphological and molecular studies of a species belonging to Bacillariophyceae collected in Northern coast of Vietnam are presented. Observations with microscope showed that this species belong to genus: Pseudo-nitzschia and seem like P. pungens. Sequence data from the partial 18S small subunit ribosomal RNA gene (18S rDNA) and the internal transcribed spacer 1 - 5.8S - internal transcribed 2 have been used to determine clearly and generate a phylogenetic framework of the obtained sequences to previously reported sequences in GenBank. These results allowed us to highlight described species of Bacillariophyceae in Northern coast of Vietnam. Furthermore, accumulation of molecular study would be helpful for the identification of scientific name of harmful algal species and further taxonomic studies in Vietnam.

• Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.273-277
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• 2013

Vibriosis caused by Vibrio anguillarum and edwardsiellosis caused by Edwardsiella tarda are septicemic diseases of many commercially important freshwater and marine fishes, and threaten the aquaculture industry in Korea. Early diagnosis and accurate identification of these two bacterial species could help to prevent these diseases and minimize the damage to cultured marine species. This study designed a duplex polymerase chain reaction (PCR) method for the simultaneous detection of two major fish pathogens: V. anguillarum and E. tarda. Each pair of oligonucleotide primers exclusively amplified the target groEL gene of the specific microorganism. Twenty-two Vibrio and ten non-Vibrio enteric species were used to check the specificity of the primers, which were found to be highly specific for the target species, even among closely related species. The detection limit was 400 pg for V. anguillarum and 4 ng for E. tarda when mixed purified DNA was used as the template. This assay showed high specificity and sensitivity in the simultaneous detection of V. anguillarum and E. tarda from artificially inoculated seawater and fish.

• Proceedings of the Zoological Society Korea Conference
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• 2001.10a
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• pp.259.1-259
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• 2001

No Abstract, See Full Text