• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.51 no.1
• /
• pp.79-85
• /
• 2015

Three specimens of larvae (5.2~7.8 mm in standard length (SL)), of the family Scombridae, were collected from the southeastern waters off Jeju Island in August, 2014. These specimens were identified to Katsuwonus pelamis have melanophores distributed on the 1st dorsal-fin spines and post ventral margin on caudal peduncle. An analysis of the cytochrome oxidase submit I (COI) sequences (652 base pairs) of mitochondrial DNA showed that our specimens must be K. pelamis, because their sequences were concordant with those of the adult K. pelamis (genetic distance= 0.000~0.002), followed by Auxis rochei (genetic distance= 0.061~0.063) and Euthynnus affinis (genetic distance= 0.077~0.079). During the larval stage, K. pelamis differed from Thunnus spp. species in melanophores distribution period of 1st dorsal-fin spines, lower jaws and ventral margin on caudal peduncle. In conclusion, occurrence of K. pelamis larvae means Korean waters are potential spawning ground of K. pelamis.

• Biomolecules & Therapeutics
• /
• v.13 no.4
• /
• pp.220-226
• /
• 2005

The present study was performed to evaluate combination effect of 7$\beta$-hydroxycholesterol (7$\beta$-OHC) and $\gamma$-radiation in NCI-H460 human lung cancer cells. 7$\beta$-OHC in combination with $\gamma$-irradiation has an enhanced effect in decreasing clonogenic survival and increasing cellular DNA damage. Pretreatment of cells with 7$\beta$-OHC enhanced radiation-induced apoptosis. Apoptosis of the cells by combined treatment of 7$\beta$-OHC and $\gamma$-irradiation was associated with reactive oxygen species generation and loss of mitochondrial membrane potential, resulting in the activation of caspase 9 and caspase 3. The combined treatment also resulted in an increased G1 cell cycle distribution. These results indicate that 7$\beta$-OHC shows the additive effect of radiation sensitivity in human lung carcinoma cells in vitro.

• Parasites, Hosts and Diseases
• /
• v.56 no.5
• /
• pp.453-461
• /
• 2018

The aim of this study is to delineate 'admixed hybrid' and 'introgressive' Fasciola genotypes present in the Fasciola population in Vietnam. Adult liver flukes collected from ruminants in 18 Provinces were morphologically sorted out by naked eyes for small (S), medium (M) and large (L) body shapes; and human samples (n=14) from patients. Nuclear ribosomal (rDNA) ITS1 and ITS2, and mitochondrial (mtDNA) nad1 markers were used for determination of their genetic status. Total 4,725 worm samples of ruminants were tentatively classified by their size: 6% (n=284) small (S)-, 13% (n=614) medium (M)-, and 81% (n=3,827) large (L)-forms. All the representative (n=120, as 40 each group) and 14 human specimens, possessed maternal mtDNA of only F. gigantica and none of F. hepatica. Paternally, all (100%) of the L-(n=40) and 77.5% (n=31) of the M-flukes had single F. gigantica rDNA indicating 'pure' F. gigantica. A majority (90%, n=36) of the S- and 15% (n=6) of the M-worms had single F. hepatica rDNA, indicating their introgressive; the rest (10%, n=4) of the S- and 7.5% (n=3) of the M-flukes had mixture of both F. gigantica and F. hepatica rDNAs, confirming their admixed hybrid genetic status. Fourteen human samples revealed 9 (64%) of pure F. gigantica, 3 (22%) of introgressive and 2 (14%) of admixed hybrid Fasciola spp. By the present study, it was confirmed that the small worms, which are morphologically identical with F. hepatica, are admixed and/or introgressive hybrids of Fasciola spp., and able to be the pathogens of human fascioliasis.

• Journal of Ecology and Environment
• /
• v.44 no.3
• /
• pp.185-195
• /
• 2020

Background: The flathead grey mullet Mugil cephalus has the widest distribution among mugilid species. Recent studies based on mitochondrial DNA sequences showed that the species comprises at least 14 different groups, three of which occur in the northwest Pacific. We analyzed the otolith microchemistry of M. cephalus at several locations in Korea to improve understanding of migration pattern and population origin. Results: We collected 123 sagittal otoliths from seven locations and determined their concentrations of eight elements (⁷Li, ²⁴Mg, ⁵⁵Mn, ⁵⁷Fe, ⁶⁰Ni, ⁶³Cu, ⁸⁸Sr, and ¹³⁸Ba) using laser ablation inductively coupled plasma mass spectrometry. Mean otolith elemental ratios differed significantly among the locations. The Sr:Ca, Fe:Ca, and Ba:Ca ratios were significantly higher than others, and useful chemical signatures for investigating the habitat use of M. cephalus populations. We identified five diverse and complicated migration patterns using the otolith data that we collected: estuarine resident (type I), freshwater migrant (type II), estuarine migrant (type III), seawater resident (type IV), and seawater migrant (type V). A canonical discriminant analysis plot revealed separation of two groups (type II in the Yellow Sea vs. other types in remaining locations). Two locations on Jeju Island, despite their close proximity, had fish with quite different migration patterns, corroborating previous molecular studies that distinguished two groups of fishes. Conclusion: We successfully showed that the migration patterns of the Korean mullet varied by location. Only fish from the western sector of Jeju had a unique migration pattern, which is likely confined population in this area. Among the eight otolith elements measured, the Sr:Ca ratio was found to be the best indicator of migration pattern and population origin.

• ALGAE
• /
• v.30 no.3
• /
• pp.217-222
• /
• 2015

Pythium species (Pythiales, Oomycetes) are well known as the algal pathogen that causes red rot disease in Pyropia / Porphyra species (Bangiales, Rhodophyta). Accurate species identification of the pathogen is important to finding a scientific solution for the disease and to clarify the host-parasite relationship. In Korea, only Pythium porphyrae has been reported from Pyropia species, with identifications based on culture and genetic analysis of the nuclear internal transcribed spacer (ITS) region. Recent fungal DNA barcoding studies have shown the low taxonomic resolution of the ITS region and suggested the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene as an alternative molecular marker to identify Pythium species. In this study, we applied an analysis of both the ITS and cox1 regions to clarify the taxonomic relationships of Korean Pythium species. From the results, the two closely related Pythium species (P. chondricola and P. porphyrae) showed the same ITS sequence, while the cox1 marker successfully discriminated P. chondricola from P. porphyrae. This is the first report of the presence of P. chondricola from the infected blade of Pyropia yezoensis in Asia. This finding of the algal pathogen provides important information for identifying and determining the distribution of Pythium species. Further studies are also needed to confirm whether P. chondricola and P. porphyrae are coexisting as algal pathogens of Pyropia species in Korea.

• Journal of Applied Biological Chemistry
• /
• v.58 no.4
• /
• pp.383-387
• /
• 2015

A duplex polymerase chain reaction (PCR) detection method was developed to authenticate the use of cat and rabbit in food and to prevent unlawful distribution of illegally butchered meat in both domestic and imported food market. Species-specific primers were designed targeting mitochondrial cytochrome b gene. The sizes of PCR products were 191 bp for cat and 101 bp for rabbit, which were relatively small for better application of the detection method on processed foods. Specificities of primers were verified using 21 animal species including cat and rabbit. Limit of detection was examined by serial dilution of the sample DNA and confirmed as 0.005 ng for rabbit and 0.0005 ng for cat using Bioanalyzer. The developed duplex PCR method showed specificity and sensitivity in the identification of two target species.

• Korean Journal of Veterinary Research
• /
• v.57 no.2
• /
• pp.89-95
• /
• 2017

This study was conducted to determine the effects of biophoton treatment during in vitro maturation (IVM) and/or in vitro culture (IVC) on oocyte maturation and embryonic development in pigs. An apparatus capable of generating homogeneous biophoton energy emissions was placed in an incubator. Initially, immature pig oocytes were matured in the biophoton-equipped incubator in medium 199 supplemented with cysteine, epidermal growth factor, insulin, and gonadotrophic hormones for 22 h, after which they were matured in hormone-free medium for an additional 22 hr. Next, IVM oocytes were induced for parthenogenesis (PA) or provided as cytoplasts for somatic cell nuclear transfer (SCNT). Treatment of oocytes with biophoton energy during IVM did not improve cumulus cell expansion, nuclear maturation, intraoocyte glutathione content, or mitochondrial distribution of oocytes. However, biophoton-treated oocytes showed higher (p < 0.05) blastocyst formation after PA than that in untreated oocytes (50.7% vs. 42.7%). In an additional experiment, SCNT embryos produced from biophoton-treated oocytes showed a greater (p < 0.05) number of cells in blastocysts (52.6 vs. 43.9) than that in untreated oocytes. Taken together, our results demonstrate that biophoton treatment during IVM improves developmental competence of PA- and SCNT-derived embryos.

• Animal cells and systems
• /
• v.3 no.4
• /
• pp.393-397
• /
• 1999

Length variations in human mitochondrial DNA (mtDNA) offer useful markers in the study of female aspects of human population history. One such length variation is a 9-bp deletion in the small noncoding segment located between the COII and Iysine tRNA genes (COII/tRNA/$^{Lys}$ intergenic region) which usually contain two tandemly arranged copies of a 9-bp sequence (ccccctcta) in human mtDNA. The mtDNA 9-bp deletion and polymorphic variants of expanded 9-bp repeat motif in the intergenic COII/tRNA$^{Lys}$ region have been found at varying frequencies among different human ethnic groups. We have examined the length variation of the mtDNA COII/tRNA$^{Lys}$ intergenic region from a total of 813 individuals in east Asian populations. The occurrence of the 9-bp deletion was found to be relatively homogeneous in northeast Asian populations (Chinese, 14.2%; Japanese, 14.3%: Koreans, 15.5%), with the exception of Mongolians (5.1%). In contrast, Indonesians (25.0%) and Vietnamese (23.2%) of the southeast Asian populations appeared to have relatively high frequencies of the 9-bp deletion. We identified the existence of a new expanded 9-bp repeat motif which likely resulted from a slipped mispairing insertion of six more cytosines in the intergenic COII$^{Lys}$ region. It was present at low frequencies in the Korean (2/349) and Japanese populations (2/147). Based on the results of this study, the Korean population may reflect a close genetic affinity with the Japanese and Chinese populations than the others surveyed east Asian populations.

• Development and Reproduction
• /
• v.2 no.1
• /
• pp.39-43
• /
• 1998

The synthesis of steroid hormone starts from cholesterol. Steroidogenic acute regulatory protein(StAR) transfers cholesterol acutely from the outer mitochondrial membranes to the inner in the early step of steroidogenesis. Many kinds of steroid hormones are mainly synthesized in adrenal grand, ovary and testis. The purpose of this study is to determine the distribution of StAR mRNA in the rat ovary and adrenal gland and to confirm the functions of StAR in these organs. In the ovary, StAR mRNAs were strongly expressed in the corpus luteum, where progesterone is synthesized, and these were weakly expressed in the theca layer of follicles, where androgen is synthesized. However, StAR mRNAs were not detected in the estrogen producing granulosa cells of growing follicles. In the corpus luteum, StAR mRNAs were strongly loclized in the zona fasciculata and zona reticularis, where glucocorticoid is mainly synthesized. StAR mRNAs were weakly expressed in the zona gromerulosa, where mineralcorticoid is synthesized. StAR mRNAs were not detected in the adrenal medulla. In our results, StAR mRNAs were expressed differentially in the steroidogenic cells of ovary and adrenal gland according to the types of steroid hormones, and the statges of corpus luteum development. We conclude that StAR is involved in the steroidogenesis at the very early step of steroid synthesis cascade.

• Animal Systematics, Evolution and Diversity
• /
• v.28 no.4
• /
• pp.279-290
• /
• 2012

Plecoglossus altivelis (ayu) is an amphidromous fish widely distributed in Northeastern Asia from the East China Sea to the northern Japanese coastal waters, encompassing the Korean Peninsula within its range. The shore lines of northeastern region in Asia have severely fluctuated following glaciations in the Quaternary. In the present study, we investigate the population genetic structure and historical demographic change of P. altivelis at a population level in East Asia. Analysis of molecular variance (AMOVA) based on 244 mitochondrial control region DNA sequences clearly showed that as the sampling scope extended to a larger geographic area, genetic differentiation began to become significant, particularly among Northeastern populations. A series of hierarchical AMOVA could detect the genetic relationship of three closely located islands between Korea and Japan that might have been tightly connected by the regional Tsushima current. Neutrality and mismatch distribution analyses revealed a strong signature of a recent population expansion of P. altivelis in East Asia, estimated at 126 to 391 thousand years ago during the late Pleistocene. Therefore it suggests that the present population of P. altivelis traces back to its approximate demographic change long before the last glacial maximum. This contrasts our a priori expectation that the most recent glacial event might have the most crucial effect on the present day demography of marine organisms through bottleneck and subsequent increase of effective population size in this region.