• Korean Journal of Microbiology
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• v.37 no.4
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• pp.312-316
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• 2001

To improve the ethanol fermentability, four Saccharomyces yeast strains with efficient ethanol fermentability were subjected to rare-mating and protoplast fusion. Using these 4 strains, 5 different combinations of mating-pair or fusion-pair were constructed and their hybrids or fusants were obtained. From the statistical analysis of the results of the ethanol fermentation by the hybrids of the different mating-pair or fusion-pair, no difference was found in ethanol production, but [S. kluveri $khl{\times}S$ cerevisiae cp3] pair was shown to be the best combination which can produce high cell-viability. In fact, the clone No. 3 of the [S. kluveri $khl{\times}S$ cerevisiae cp3] pair was selected as the best strain which produced ethanol of 10.11% (w/v) or 12.81% (v/v) from 25% (w/v) glucose at $33^{\circ}C$ for 3 days with the residual sugar of 3.53% (w/v), viability of 62.65%, fermentation efficiency of 92.2%.

• Microbiology and Biotechnology Letters
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• v.29 no.4
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• pp.212-220
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• 2001

Rare mating was used to select a respiratory deficient mutant of Saccharomyces cerevisiae HDC52 strain. Glucoamylase gene of S. diastaticus K114 was developed into the RD mutant which could uptake maximum amount of non-fermentable sugars through the expression of glu- coamplyase gene and the fermentation characteristics of the developed strain HCS were investigated. The size of HCS yeast and HBD52 yeast strain were 13 $\mu\textrm{m}$ and 10$\mu\textrm{m}$ respectively. HCS strain which can uptake maximum amount of non-fermentable sugar through the expression of glucoamylase gene was developed. By karyotype anal- ysis. HCS stain but not RD mutant HBC52 showed a band of 1150 kb chromosome DNA This band should include glcoamylase gene from Saccharomyces diataticus K114 THis strain has glucoamylase which can degrade starch By transduction and contrnuance of glucoamylase gene HCS strain gegraded strach and formed halo. Also, HCS strain maintained the character after 50 generations. Glucoamylase activities of Saccharomyces diastaticus K114 and HCS yeast strains are 9.5 and 2.7~3.4(unit/ml) HCS and HBC52 strain showed similar sugar fermentation patterns and low flocculation In spore and film forming test, HCS and HBC52 strain formed neither spores nor films. In the limit fermentation test, HBC52 strain showed fermentation level of 68% and HCS strain showed 76~78% As the limit attenuation of HBC52 and HCS were ($2.00^{\circ}$P) and ($0.7~0.93^{\circ}$P) This study demon- strates and HCS strain may be used for low carbohydrate beer fermentation.

• 주류공업
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• v.15 no.1
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• pp.44-57
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• 1995

• Korean Journal of Environmental Biology
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• v.37 no.1
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• pp.88-92
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• 2019

The objective of this study was to report the group mating of Asian Keelback snake, Hebius vibakari, in South Korea. On May 20, 2009, the group mating of H. vibakari was observed in the Maeng-gol do, Jindo-gun, Jeollanam-do, in the rocky area (107 m above sea level) on the ridge of the island. Six female and five male snakes made a form of mating behavior called "mating ball". Two couples showed "tail-wrestling" which is the copulation behavior in snake species. During the mating, the temperature and humidity were $25.7^{\circ}C$ and 59%, respectively. The result of this study was the first case report of the group mating in H. vibakari, a rare reptile.

• The Korean Journal of Zoology
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• v.31 no.1
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• pp.1-10
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• 1988

A syrnpatnc sample of Rana nigrnmaculata sand R plancyi (Anura) from Kwangu, Korea was investigated to clarify their taxonornic status and to estimate the degree of genic variation, genetic relatedness, and reproductive isolation between them, based on electrophoretic analysis, marphometric data, mating call, mating season, and habitat. All the characters measured including morphometric, genetic, behavioral, and ecological suggest that they are distinct species and R nigrnmaculata might have originated from R plancyi (tropical form about three and a half million years ago. An adult female was found to be Fl hybrid between two species The hybrid female possessed fettile eggs and morphologically intermediate to the parental species in head parts, hind limb, and web characters. The differences in mating call, mating behavior, breeding season, and habitat strongly suggest that postmating isolating mechanism is operating, even though very rare hybrid is found.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.317-317
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• 1997

No Abstract, See Full Text

• Microbiology and Biotechnology Letters
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• v.39 no.2
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• pp.111-118
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• 2011

For the strain improvement of the industrial polyploid yeast strain through hybridization and protoplast fusion, a dominant selection marker other than a recessive marker such as the auxotrophic marker was required for the selection of the resulting hybrids. In the present investigation, the aureobasidin A resistant gene was tested in relation to whether it can be used as the dominant selectable marker for the isolation of hybrids of the yeast Saccharomyces. The plasmid pAUR112, carrying the gene responsible for resistance to aureobasidin A, was introduced into the haploid yeast strain K114/YIp. From the rare-mating between polyploid C6 and haploid K114/YIp carrying pAUR112, many hybrids were obtained from the agar medium containing 0.5 ${\mu}g$/ml of aureobasidin A. The hybrids exhibited characteristics derived from both of the parental strains; and the cell sizes of the hybrids were larger than those of the parental strains. These results showed that the aureobasidin A resistant gene could be successfully used as the dominant selectable marker for the isolation of yeast hybrids resulting from rare-mating.

• Microbiology and Biotechnology Letters
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• v.22 no.6
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• pp.584-592
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• 1994

Several mutation procedures have been compared to obtain an ethanol-tolerant Saccha- romyces diastaticus strain secreting glucoamylase. These procedures include spontaneous mutation, EMS treatment, UV irradiation, and combination of EMS treatment and UV irradiation. All these methods were followed by adaptation of the yeast cells to gradually higher ethanol concentration. Among these procedures, the combined method of EMS treatment and UV irradiation gave the promising result, i.e. the ethanol tolerance of the yeast increased from 11.5%(v/v) to 14.0%(v/v). Respiratory deficient petite mutants of industrial and ethanol-tolerant yeast strains have been isola- ted and hybridized with haploid S. diastaticus strains. The resulting hybrids showed increased ethanol tolerance and starch-fermentability.

• Journal of Embryo Transfer
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• v.32 no.2
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• pp.53-58
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• 2017

It is very difficult to get the information about semen quality analysis in transgenic pigs because of limited numbers and research facilities. Therefore, in the present study, we analyzed the semen quality of transgenic boars generated for xenotransplantation research. Briefly, the semen samples were collected from 5 homozygous ${\alpha}1,3$-Galactosyltransferase knock-out ($GalT^{-/-}$) transgenic boars and immediately transported to the laboratory. These semen samples were decupled with DPBS and conducted to analyze semen parameters by a computer-assisted semen analysis (CASA) system. The boar semen were examined all 12 parameters such as total motility (TM), curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP), and hyperactivated (HYP), etc. In results, among the 5 $GalT^{-/-}$ boars, three boars (#134, 144, and 170) showed normal range of semen parameters, but #199 and 171 boars showed abnormal ranges of semen parameters according to standard ranges of semen parameters. Unfortunately, #171 boar showed azoospermia symptom with rare sperm counts in the original semen. Conclusively, assessment of semen parameters by CASA system is useful to pre-screening of reproductively healthy boar prior to natural mating and artificial insemination for multiplication and breeding.

• Korean Journal of Veterinary Pathology
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• v.2 no.2
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• pp.127-138
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• 1998

Transmissible venereal tumor(TVT) is a naturally occurring contagious neoplasm which can be transmitted by mechanical contact during mating in dogs and transplanted as intact viable cells to dogs and other members of canine family such as coyotes, jackals, wolves, and foxes. The incidence of this tumors tends to increase in Korean native Jindo dogs. This is probably due to the high density and unrestrained management system. With time, TVT reaches the maximum size and then tends to regress spontaneously unless individuals are immunologically compromised. It consists of different types of cells depending on the stage. In this study, 10 tumors were selected from Jindo dogs. These were histologically calssified into three stages; progressive, steady-state, and regressive. Mitotic figures were counted, and their histological appearance at each stage is compared with their DNA ploidy. Histologically, 5 tumor cases were calssed as the progressors, 3 cases as the steady-state tumors, and 2 cases as regressors. Progressors were composed of round cells with large nuclei containing conspicuous nucleoli and frequent mitotic figures. A few spindle-shaped cells and inflammatory cells including mainly lymphocytes, a few neutrophils and macrophages were also seen. In the steady-state tumors, there was an increased number of spindle shaped cells and mitotic figures were rare. Six tumors were diploid and four were aneuploid with the variation coefficient of 7.02. Two of five progressive tumors were aneuploid. Two of three steady-state tumors were aneuploid while both tumors at the regressive stage were diploid. Progressive and steady-state tumors had a much larger S/G2M fraction and a higher mitotic index than regressive tumors. Two tumors which persisted for more than one year were aneuploid. These results suggest that the progressive and steady-state tumors had more active cell division than the regressive neoplasms.