• Journal of Life Science
• /
• v.21 no.8
• /
• pp.1199-1203
• /
• 2011

The present study evaluated the beneficial effects of polycalcium (a mixture of Polycan and calcium lactate-gluconate 1:9 [g/g]) on osteoporosis using in vitro assays. Cell proliferation and alkaline phosphatase activities of osteoblasts (human primary osteoblasts) and osteoclast differentiation of RAW264.7 cells (murine osteoclast progenitor cells) treated with different concentrations of polycalcium for various periods were assessed. Osteoblast proliferation was stimulated and prevented RANKL-induced osteoclast differentiation of RAW264.7 cells. These results support the development of ideal anti-osteoporotic agents, such as polycalcium, that exhibit properties that accelerate bone formation and inhibit bone resorption.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.17 no.1
• /
• pp.25-31
• /
• 2012

The frequency and abundance of jellyfish, presumably related with climate change, fisheries overexploitation, marine pollution including land reclamation and dyke construction, are increasing worldwide. This feature has attracted interest and concerns from general public and public officials, and government is seeking how the damages could be prevented or reduced down. Korean government, having recent huge blooms of jellyfish, engaged in reducing and/or countermeasuring jellyfish damages. Korean research themes include ecology and physiology of blooming jellyfish species, understanding of the blooming mechanism, and focus on the eradication of blooming jellyfish, without governmental integrative management plan. EU is undertaking scientific projects focused on understanding of the mechanism and control of jellyfish blooms, and establishment of an integrative management. In USA, government has established the code on jellyfish management for conserving and protecting the fish and shellfish resources and one of its department is specially assigned to monitor jellyfish appearance, undertake research, and prepare management plan. Japan also assigned a department and research institute for jellyfish research. Their main interest is to predict jellyfish drifting and mass bloom. Compared to Korea, USA, EU and Japan emphasize integrative management that includes ecological understanding, public education and outreaches, communication and control, if possible, of jellyfish blooms, based on scientific data. We suggest then, 1) establishment of an integrative scientific system consisting of policy and scientific experts to prepare inter-ministrial integrative management plan to effectively combat jellyfish blooms and to maximize the scientific result; 2) concept change from harmful to exploitable marine animal in policy making and research; and 3) active education and information service for people. We expect that these suggestions can be useful for jellyfish management and policy making on another harmful marine organisms.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.17 no.2
• /
• pp.125-131
• /
• 1984

The horn fish, Hemiramphus sajori TEMMINCK et SCHLEGEL, is widely distributed in the coastal waters of Korea, Japan and Taiwan. On April 13, 1983, mature adults of the horn fish were collected from Changson channel, Namhae. The authors carried out artificial insemination on the field, and incubated the eggs and reared larvae in the laboratory. And these larvae were reared for about two weeks in glass jars, fed brine shrimp nauplii. The eggs of this species are demersal and adhesive, with 4 to 6 filaments at the animal pole and a filament at the vegetal pole. The diameter of these eggs varies 1.80 to 2.00 mm. The hatching took place in ca. 376 hours after fertilization. During the incubation period water temperature fluctuated between $13.5^{\circ}C\;and\;20.0^{\circ}C$. The newly hatched larvae were elongate in shape $7.40{\sim}8.00$ mm in total length with $40+16{\sim}17=56{\sim}57$ myomers. Many melanophore were distributed on the head, both sides of dorsal body contour, peritoneum and ventral line of the tail part. Four days after hatching, the larvae were from 9.00 to 9.65 mm in total length, at this tims the larvae absorbed the yolk completely, and became postlarvae. Fourteen days after hatching, the larvae attained 13.25 mm in total length, with 14 rays of the dorsal fin, 13 rays of the anal fin, and 4 rays of pectoral fin. The lower jaw has somewhat projected.

• Fisheries and Aquatic Sciences
• /
• v.19 no.1
• /
• pp.4.1-4.7
• /
• 2016

This study evaluated the dietary lysine requirement by measuring the plasma free lysine concentrations in rainbow trout, Oncorhynchus mykiss after dorsal aorta cannulation. A basal diet containing 36.6 % crude protein (29.6 % crystalline amino acids mixture, 5 % casein and 2 % gelatin) was formulated to one of the seven L-amino acid based diets containing graded levels of lysine (0.72, 1.12, 1.52, 1.92, 2.32, 2.72 or 3.52 % dry diet). A total of 35 fish averaging $512{\pm}6.8g$ ($mean{\pm}SD$) were randomly distributed into seven groups with five fish in each group. After 48 h of feed deprivation, each group of fish was fed one of the experimental diets by intubation at 1 % body weight. Blood samples were taken at 0, 5 and 24 h after intubation. Post-prandial plasma free lysine concentrations (PPlys, 5 h after intubation) of fish fed diets containing ${\geq}2.32%$ lysine were higher than those of fish fed diets containing ${\leq}1.92%$ lysine. Post-absorptive free lysine concentrations (PAlys, 24 h after intubation) of fish fed diets containing 2.32 and 3.52 % lysine were higher than those of fish fed diets containing ${\leq}1.52%$ lysine. The brokenline regression analysis on the basis of PPlys and PAlys indicated that the lysine requirement of rainbow trout could be 2.34 and 2.20 % in diet. Therefore, these results strongly suggested that the dietary lysine requirement based on the broken-line model analyses of PPlys and PAlys could be greater than 2.20 % but less than 2.34 % (corresponding to be $6.01%{\leq},but{\leq}6.39%$ in dietary protein basis, respectively) in rainbow trout. Also, these results shown that the quantitative estimation of lysine requirement by using PPlys and PAlys could be an acceptable method in fish.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.4
• /
• pp.555-562
• /
• 2012

PCR was performed to analyze the ${\beta}$-lactamase genes carried by ampicillin-resistant Vibrio spp. strains isolated from marine environments in Korea between 2006 and 2009. All 36 strains tested showed negative results in PCR with the primers designed from the nucleotide sequences of various known ${\beta}$-lactamase genes. This prompted us to screen new ${\beta}$-lactamase genes. A novel ${\beta}$-lactamase gene was cloned from Vibrio alginolyticus KV3 isolated from the aquaculture water of Geoje Island of Korea. The determined nucleotide sequence (VAK-3 ${\beta}$-lactamase) revealed an open reading frame (ORF) of 852 bp, encoding a protein of 283 amino acids (aa), which displayed low homology to any other ${\beta}$-lactamase genes reported in public databases. The deduced 283 aa sequence of VAK-3, consisting of a 19 aa signal peptide and a 264 aa mature protein, contained highly conserved peptide segments specific to class A ${\beta}$-lactamases including the specific amino acid residues STFK (62-65), SDN (122-124), E (158), and RTG (226-228). Results from PCR performed with primers specific to the VAK-3 ${\beta}$-lactamase gene identified 3 of the 36 isolated strains as V. alginolyticus, Vibrio cholerae, and Photobacterium damselae subsp. damselae, indicating the utilization of various ${\beta}$-lactamase genes including unidentified ones in ampicillin-resistant Vibrio spp. strains from the marine environment. In a mating experiment, none of the isolates transfered the VAK-3 ${\beta}$-lactamase gene to the Escherichia coli recipient. This lack of mobility, and the presence of a chromosomal acyl-CoA flanking sequence upstream of the VAK-3 ${\beta}$-lactamase gene, led to the assumption that the location of this new ${\beta}$-lactamase gene was in the chromosome, rather than the mobile plasmid. Antibiotic susceptibility of VAK-3 ${\beta}$-lactamase was indicated by elevated levels of resistance to penicillins, but not to cephalosporins in the wild type and E. coli harboring recombinant plasmid pKV-3, compared with those of the host strain alone. Phylogenetic analysis showed that VAK-3 ${\beta}$-lactamase is a new and separate member of class A ${\beta}$-lactamases.

• Korean Journal of Environmental Biology
• /
• v.37 no.4
• /
• pp.474-482
• /
• 2019

Disease monitoring in wild aquatic animals is necessary to obtain information about disease occurrence, disease agents, and the transmission of diseases between wild and cultured species. In this study, we monitored viral diseases in wild marine fish and crustacea caught by trawl in Korea in April and October 2018. We monitored the viral diseases in 977 fish from 39 different species and 287 crustacea from 14 different species. In fish, we collected kidney and spleen to detect viral hemorrhagic septicemia virus (VHSV), red sea bream iridovirus (RSIV), marine birnavirus (MABV), hirame rhabdovirus (HRV), and lymphocystis disease virus (LCDV). In crustacea, we monitored white spot syndrome virus (WSSV), infectious hypodermal and hematopoietic necrosis virus (IHHNV), taura syndrome virus (TSV), infectious myonecrosis virus (IMNV), yellowhead disease virus (YHDV), and white tail disease virus (WTDV) using pleopods, pereiopods, gills, muscle, and hepatopancreases. Although none of the viral diseases tested in this study were detected in the samples, these results will help disease control between aquaculture species and wild aquatic animals.

• Animal cells and systems
• /
• v.14 no.1
• /
• pp.45-51
• /
• 2010

Genetic variation was surveyed at the mitochondrial control region (766bp) to test for the presence of genetic stock structure in the small yellow croaker, Larimichthys polyactis from the Yellow and East China Seas. Individuals of the small yellow croaker could not be distinguished on the basis of its location, as demonstrated using the neighbor-joining (NJ) method, unweighted pair-group method, arithmetic average (UPGMA) and the minimum spanning network (MSN). Analysis of molecular variance revealed no significant differences among collections of the small yellow croaker taken from the four locations (two locations each in Korea and China). Neutrality tests and a mismatch distribution analysis indicated that this species has recently expanded. Our findings suggest either that the small yellow croaker has a high migration capability that enables it to overcome the effects of genetic drift, or that this species expanded relatively recently and has not yet had sufficient time to differentiate.

• Korean Journal of Ichthyology
• /
• v.32 no.2
• /
• pp.110-114
• /
• 2020

A single specimen (40.5 mm in SL) of Clariger chionomaculatus was collected at 4 m depth on mud bottom from off Geojedo Island, Korea. This species is characterized by having an elongated body without scales, several barbels below eyes, I, 12~15 second dorsal fin rays, I, 12~14 anal fin rays; 19~20 pectoral fin rays with one free soft ray on upper part, and a unique color pattern with numerous white blotches on dorsal part of body. Because it has been known from Japan only to date, we describe in detail C. chionomaculatus as the first record from Korea. A new Korean name, "Huin-jeom-wae-mang-dug", is proposed for the species.

• Animal cells and systems
• /
• v.13 no.3
• /
• pp.339-344
• /
• 2009

This study aims to find out the effect of heavy metals, as is the case of EDCs (endocrine disrupting chemicals), on reproductive endocrine disruption of aquatic animals. In the present experiment zinc, which is a heavy metal well known for its androgenous activity, was used. The experimental period was 24 weeks, starting in November during the inactive stage of the clam's reproductive cycle. The experimental groups were composed of one control condition and three zinc exposure conditions (0.64, 1.07, and 1.79 mg/L). The sex ratio (F:M) was 1:1.06 in the control group and 1:1.70 in all the exposed group, illustrating the tendency for higher proportion of males with increases in zinc concentration. Gonad maturity was higher in 1.07, and 1.79 mg/L groups compared to the control group, with higher maturity observed in males than females. Intersex individuals made up 24.7% of the exposed group, while females exhibited a higher ratio than the males with increasing zinc concentration. The results of this study indicate that zinc functions as an androgenic effector on the reproduction of Gomphina veneriformis.

• Animal cells and systems
• /
• v.13 no.3
• /
• pp.351-356
• /
• 2009

Ciliates are undoubtedly one of the most diverse protozoans that play a significant role in ecology. However, molecular examination, based on comparing the DNA sequences, has been done on a limited number of the species. Because most ciliates are uncultivable and their population sizes are often too small, it is usually difficult to obtain sufficient genomic DNA required for PCR based experiments. In the present study, we evaluated the effectiveness of four commercial DNA extraction procedures that extract high quality genomic DNA from a single ciliate cell. It was discovered that RED Extract-N-$Amp^{TM}$ PCR kit is the best method for removing PCR-inhibiting substances and minimizing DNA loss during purification. This method can also amplify more than 25 reactions of PCR. In addition, this technique was applied to single cells of 19 species belonged to 7 orders under 5 classes that isolated from mixed natural populations. Their small subunit ribosomal DNA (SSU rDNA) was successfully amplified. In summary, we developed a simple technique for the high-yield extraction of purified DNA from a single ciliate cell that may be more useful for rare ciliates, such as tiny and uncultivable marine microbes.