• Journal of Environmental Science International
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• v.31 no.10
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• pp.861-868
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• 2022

The Namdae stream in Gangneung-si is one of the rivers where salmon stock is mainly maintained by natural spawning rather than artificial seedlings. There are structures including weir, and fish distribution and movement characteristics can be different by these structures. In this study, we investigated the distribution and behavioral characteristics of salmon by sighting survey within 12 km immediately upstream of the river mouth between October 2021 and February 2022. As a result, salmon distributed within 9 km from rivermouth. There were more salmon in the lower reaches of Doosan weir than in the upper reaches of that. The main spawning ground for salmon was between 7-9 km from rivermouth and around the lower part of Doosan weir. Salmon behaved for spawning in the gravel-bed area and undercut slope of the mainstream, such as mating, digging the riverbed, and competition among males. Salmon moved more slowly in the gravel-bed area than sand-bed area. Doosan weir hinders the spawning migration of salmon by frequent flow changes and terraced fishway. This study provides primary information to understand the ecological changes of salmon by environmental changes in the Namdae stream.

• The Korean Journal of Zoology
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• v.18 no.3
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• pp.141-146
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• 1975

The purposes of this study were to investigate the frequencies of acatalasemia and hypocatalasemia in Korean population to compare with those of Japanese, Chinese and chiefly Taiwan population. The results obtained were as followings; 1. In south area of Korea, Jeonju, Gwangju, Busan and Daegu, a total of 3,629 individuals were tested. No acatalasemia was found but 0.26% of hypocatalasemia in Jeonju, 0% in Gwangju, 0.21% in Busan and 0.06% in Daegu were found. 2. The frequency of hypocatalasemia in south area of Korea was found to be lower than in middle area. 3. The frequency of hypocatalasemia in this study was similar to that of Chinese(in Taiwan) and higher than that of Japanese. 4. The reason of the geographical differences in the freqency of the hypocatalasemia was considered to be due to the natural selection. And the reason of the higher frequency of Korean population living in Japan was considered that originally the frequency of Korean population is higher, and the maintenace of this higher degree is obliged to the assortative mating beteen them.

• Korean Journal of Animal Reproduction
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• v.24 no.2
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• pp.171-178
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• 2000

To improve the pig farm management and efficiency of swine industry by inducing the farrowing to day-time from night, In the first experiment, reproduction records of purebred and crossbred pigs were collected and analyzed to estimate the $\varepsilon$ ffec 잉 of factors affecting day and night farrowing. The general linear model was used to estimate the least square means of the factors affecting various reproductive characteristics. And also, chi-square tests were used to examine the independence of the reproductive traits and environmental factors using the SAS (1992). The comparisons between pure and crossbred pigs for total number born, percentage of number born alive, gestation length, time length for farrowing were determined. The results indicated that the gestation length of crossbred (115.11 d) was slightly longer than that of purebred (114.89 d, p＜0.05). For the seasonal effects on total number born, the largest was found in spring and no differences were found among summer, fall and winter. The average gestation length was 1 day longer in spring and winter than in summer and fall. The total number born and number born alive were smaller in first, second, and greater or equal to sixth parity than other parities. And also, the percentage of no. born alive was least in greater or equal to sixth parity. For the effect of mating methods, natural and artificial insemination, on total number born and number born alive, no differences between the two methods were found. However, the percentage of number born alive for natural mating was 98.06% and was higher than artificial insemination(93.75%). The time length for farrowing was I hour were found for the 6 hrs of farrowing time. In general situation of pig farms, day-time farrowing was 34.8% and night farrowing was 65.2%, indicating that night farrowing was almost double of the night farrowing.

• Korean Journal of Microbiology
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• v.30 no.2
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• pp.88-95
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• 1992

The genetically engineered microorganisms (GEMS) could be released accidentally or ii)rexperimental purposes, as the genetic engineering, technique ha:. become very popular inany laboratories of biological sciences. But there have been littlt: informations on transkrbehavior of the genetically ~nodified genes in the natural en\ironmentx. In this stutly.antibiotic resistant bacteria were isolated from nat.ural waters. and then GEM strains wereconstructed i'rom the natural isolate (NI) by ~noclification oi' the Km' plasmitl. Thetransferability of the plasmids in the GEM and NI strains were examinetl by con-jugationin Luria-Bertani broth :it 30$^{\circ}$C. Also the cff'ccts 01' mating strain and pH on their transferfrequency and rearrangement of the plasmids in tl-~ec o~ijugantsM ere comp:irati\ely stuclictl.I'hc transkr frequency of Km' plasmid in donor of GEM and N1 strains wah similar a.;about 10 ' when co~ljugation was conducted wit11 M'I'I strain is recipient at pH 7. butthat of 1)KCOOI was lowered to 1.2X 10 '. And when the lab. stlain was uhccl as recipient.the transfer tendency of the plasmid was about same in both (;EM and NI strains usedas donor. All thc tionor 5trains. except for I)KC601. showecl the Ilighcs~ frequency of about10 ' at pH 7 and the frequcncics were lowered at both pH 5 and 9. Hut the mocliliedKm' plasmid in the cloned strain of DKC601 was transferred hy very low frequency of10 "at pH 5 ant1 7 comparing to other GEM strains. especiall! any co~~.jugantws ere notobtained at pH 4 and 9 even after conjugation for 6 hours. Rearrangement of the plasmidstranskrred into the lab. strain was not found in the conjugants. I\ulcornerut a lot of rearrangclncntwas ohservecl nlhen they were transferred into the NI strain. Such a rearrangement wasmore severe when donor was GEM strain rather then NI strain Hut such ;r phenomenonwas less affected by p!-l values.r phenomenon was less affected by p!-l values.

• Korean journal of applied entomology
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• v.46 no.2
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• pp.201-212
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• 2007

This study was conducted to investigate the biology of three species, Tipula latemarginata Alexander, T. nova Walker and T. aino Alexander, of the Genus Tipula in Korea. Field surveys for the biology of the species were carried out at the three sites of Neaseong Stream area in Bongwha County from January 2001 to December 2005. Also many individuals of the species were reared in laboratory to investigate the biology. The larval habitats of the species were streams, rivers, paddy fields, damp earth or leaky revetments. The Tipula larvae were herbivorous. Newly-hatched first instar larvae fed on soft algae, and the larvae gradually fed on leaves, stems and roots of a variety of plants or hard leaf litters, as they grew. During the molting of the larvae their body kept moving from left to right and up and down. Molting usually took not more than 2 hours, and about four hours after molting, the larvae started to eat heavily. The Tipula larvae in aquatic places moved to drier land for pupation and went through short prepupal stage lasting 1-2 days for pupation at fourth instar larval stage. When emerging, the Tipula pupae placed their head and thorax on the earth, but the other parts in the earth. Emergence from the pupal case required about 20 min. to one hour. Mating of Tipula adults took place within 5-7min. after emergence and the duration of mating was about 40 min. The female adults of the species laid eggs by walking with 3 pairs of legs over the damp earth or algal beds. Their body was positioned vertically on the ground with their wings spread $120^{\circ}$ and legs landed on the surface. The oviposition usually took place from one day to 4 days after emergence and the number of eggs carried by female adults were an average of 501-760 per individual. Tipula adults didn't normally feed, and drank water only occasionally. For a few days after emergence, the adults reared in the laboratory rarely drank water. As they neared to death, however, they frequently drank water. The longevity of adults reared in the laboratory with only water during the summer was ca. 4-9 days and males usually survived a little longer than females. The longevity of T. nova was increased 3 times or more as much by feeding them 3% sugar water. Male adults of T. latemarginata outnumbered female adults by 2.6 : 1 in the fields.

• The Journal of Natural Sciences
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• v.4
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• pp.103-142
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• 1991

These studies were carried out to select somatic hybrid using selectable marker genes of Nicotiana glauca transformed by NPTII gene and Solanum tuberosum transformed by T- DNA, and to study characteristics of transformant. The results are summarized as follows. 1. Crown gall tumors and hairy roots were formed on potato tuber disc infected by A. tumefaciens Ach5 and A. rhizogenes ATCC15834. These tumors and roots could be grown on the phytohormone free media. 2. Callus formation from hairy root was prompted on the medium containing 2, 4 D 2mg/I with casein hydrolysate lg/l. 3. The survival ratio of crown gall tumor callus derived from potato increased on the medium containing the activated charcoal 0. 5-2. 0mg/I because of the preventions on the other hand, hairy roots were necrosis on the same medium. 4. Callus derived from hairy root were excellently grown for a short time by suspension culture on liquid medium containing 2, 4-D 2mg/I and casein hydrolysate lg/l. 5. The binary vector pGA643 was mobilized from E. coli MC1000 into wild type Agrobacteriurn tumefaciens Ach5, A. tumefaciens $A_4T$ and disarmed A. tuniefaciens LBA4404 using a triparental mating method with E. ccli HB1O1/pRK2013. Transconjugants were obtained on the minimal media containing tetracycline and kanamycin. pGA643 vectors were confirmed by electrophoresis on 0.7% agarose gel. 6. Kanamycin resistant calli were selected on the media supplemented with 2, 4-D 0.5mg/1 and kanamycin $100\mug$/ml after co- cultivating with tobacco stem explants and A. tumefaciens LBA4404/pGA643, and selected calli propagated on the same medium. 7. The multiple shoots were regenerated from kanamycin resistant calli on the MS medium containing BA 2mg/l. 8. Leaf segments of transformed shoot were able to grow vigorusly on the medium supplemented with high concentration of kanamycin $1000\mug$/ml. 9. Kanamycin resistant shoots were rooting and elongated on medium containing kanamycin $100\mug$/ml, but normal shoot were not. 10. For the production of protoplast from potato calli transformed by T-DNA and mesophyll tissue transformed by NPTII gene, the former was isolated in the enzyme mixture of 2.0% celluase Onozuka R-10, 1.0% dricelase, 1.0% macerozyme. and 0.5M mannitol, the latter was isolated in the enzyme mixture 1.0% Celluase Onozuka R-10, 0.3% macerozyme, and 0.7M mannitol. 11. The optimal concentrationn of mannitol in the enzyme mixture for high protoplast yield was 0.8M at both transformed tobacco mesophyll and potato callus. The viabilities of protoplast were shown above 90%, respectively. 12. Both tobacco mesophyll and potato callus protoplasts were fused by using PEG solution. Cell walls were regenerated on hormone free media supplemented with kanamycin after 5 days, and colonies were observed after 4 weeks culture.

• Journal of Embryo Transfer
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• v.26 no.1
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• pp.79-84
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• 2011

This study was performed to identify the differentially methylated region (DMR) and to examine the mRNA expression of the imprinted H19 gene in day 35 of SCNT pig fetuses. The fetus and placenta at day 35 of gestation fetuses after natural mating (Control) or of cloned pig by somatic cell nuclear transfer (SCNT) were isolated from a uterus. To investigate the mRNA expression and methylation patterns of H19 gene, tissues from fetal liver and placenta including endometrial and extraembryonic tissues were collected. The mRNA expression was evaluated by real-time PCR and methylation pattern was analyzed by bisulfite sequencing method. Bisulfite analyses demonstrated that the differentially methylated region (DMR) was located between -1694 bp to -1338 bp upstream from translation start site of the H19 gene. H19 DMR (-1694 bp to -1338 bp) exhibits a normal mono allelic methylation pattern, and heavily methylated in sperm, but not in oocyte. In contrast to these finding, the analysis of the endometrium and/or extraembryonic tissues from SCNT embryos revealed a complex methylation pattern. The DNA methylation status of DMR Region In porcine H19 gene upstream was hypo methylated in SCNT tissues but hypermethylated in control tissues. Furthermore, the mRNA expression of H19 gene in liver, endometrium, and extraembryonic tissues was significantly higher in SCNT than those of control (p<0.05). These results suggest that the aberrant mRNA expression and the abnormal methylation pattern of imprinted H19 gene might be closely related to the inadequate fetal development of a cloned fetus, contributing to the low efficiency of genomic reprogramming.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.519-527
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• 2014

Deutzia paniculata is an endemic species, which is geographically restricted within southern part of Korea. Four populations of D. paniculata were sampled across its natural range, from the smallest population, Mt. Dalum, which held less than 100 individuals, to the largest, Mt. Unmum, over 3,500 individuals. Artificial pollination study showed that D. paniculata had an obligate outcross breeding system. Major pollinators were two bee species, Lasioglossum exiliceps and Allograpta balteata (de Geer). The breeding system and patterns of allozyme variation of D. paniculata were investigated to understand the population biology and to explain on reserve designs and management proposals relevant to this species. D. paniculata held relatively low genetic variation at the eight allozyme loci surveyed. Measures of genetic variation in this species alleles per locus ($A_s=1.33$), proportion of polymorphic loci (P=23.85%), and expected heterozygosity ($H_{es}=0.110$) were similar to values reported for endemic species. Mt. Dalum population (DAL) was composed with one clone based on allozyme data. Individuals of D. paniculata were frequently included in root connected clusters. Population genetic structure between and within four populations was probably the result of shrinking effective population size and the extinctions of intervening populations. For the conservation of genetic diversity, maximum number of different genotype need to be protected based on genetic structure and mating system.

• Development and Reproduction
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• v.21 no.2
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• pp.157-165
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• 2017

One of the reasons to causing blood coagulation in the tissue of xenografted organs was known to incompatibility of the blood coagulation and anti-coagulation regulatory system between TG pigs and primates. Thus, overexpression of human CD73 (hCD73) in the pig endothelial cells is considered as a method to reduce coagulopathy after pig-to-non-human-primate xenotransplantation. This study was performed to produce and breed transgenic pigs expressing hCD73 for the studies immune rejection responses and could provide a successful application of xenotransplantation. The transgenic cells were constructed an hCD73 expression vector under control porcine Icam2 promoter (pIcam2-hCD73) and established donor cell lines expressing hCD73. The numbers of transferred reconstructed embryos were $127{\pm}18.9$. The pregnancy and delivery rate of surrogates were 8/18 (44%) and 3/18 (16%). The total number of delivered cloned pigs were 10 (2 alive, 7 mummy, and 1 died after birth). Among them, three live hCD73-pigs were successfully delivered by Caesarean section, but one was dead after birth. The two hCD73 TG cloned pigs had normal reproductive ability. They mated with wild type (WT) MGH (Massachusetts General Hospital) female sows and produced totally 16 piglets. Among them, 5 piglets were identified as hCD73 TG pigs. In conclusion, we successfully generated the hCD73 transgenic cloned pigs and produced their litters by natural mating. It can be possible to use a mate for the production of multiple transgenic pigs such as ${\alpha}-1,3-galactosyltransferase$ knock-out /hCD46 for xenotransplantation.

• Journal of Veterinary Clinics
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• v.23 no.2
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• pp.123-128
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• 2006

Production of cloned pigs by somatic cell nuclear transfer (SCNT) has unlimited value for developing critical biotechnology such as xenotransplantation. Various efforts have been made to establish this technology, and several litters of live piglets have been produced after transfer of SCNT embryos. However, the efficiency is very low compared to piglet production by artificial insemination or natural mating. So far, most studies have been limited to in vitro production of SCNT embryos. This study was conducted to standardize a surrogate recipient (gilts) for transfer of SCNT embryos to improve pregnancy rate. Potential surrogate gilts over 7 months of age were checked for their estrous status by observing external signs; vaginal fluid, vulva redness, vulva swelling, and standing response to back pressure. Viscosity of vaginal fluid was evaluated and classified as none (0), medium (1), and strong (2). Vulva redness and swelling was respectively assessed by none or shrink (0), medium (1), strong (2). Back pressure was estimated by an immediate move (0), standing less than 10 sec (1), and standing over 10 see (2). And then ovulation status of each surrogate was classified as pre-ovulation (PO-17 surrogates), just prior to ovulation (JPO-20 surrogates), in ovulation (IO-12 surrogates), just after ovulation (JAO-14 surrogates) and after ovulation (AO-24 surrogates) at the time of surgery for embryo transfer (ET). Real-time ultrasonographic scanners have been used for pregnancy diagnosis by observing amniotic vesicles. The first pregnancy diagnosis was done on Day 30 after ET and then repeated 2-week interval. In the results, SCNT embryos transferred into JPO surrogates gave better pregnancy rates (45%) than others (4% to 11%) on Day 30 after ET. These result indicates that surrogate gilts in a status just prior to ovulation can offer optimal condition to establish pregnancy by transfer of SCNT pig embryos.