• Research in Plant Disease
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• v.28 no.1
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• pp.26-31
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• 2022

Pseudomonas syringae pv. actinidiae (Psa) is the causal agent responsible for the bacterial canker disease of kiwifruit plants. Psa strains are divided into five different biovars based on genetic and biochemical characteristics. Among them, biovar 2 and 3 strains of Psa were isolated and have been causing widespread damages in Korea. One of the most effective ways to control Psa is to use an antibiotic such as streptomycin. However, Psa strains resistant to this antibiotic were isolated in Korea, and an earlier study revealed that the resistance in the biovar 2 is associated with strA-strB genes. This study aimed to determine the molecular resistance mechanism of Psa biovar 3 strains to streptomycin. Sequencing the rpsL gene encoding ribosomal protein S12 from three streptomycin-resistant strains screened in the laboratory revealed that a spontaneous mutation occurred either at codon 43 or 88. Meanwhile, in four streptomycin-resistant strains of Psa biovar 3 isolated from two kiwifruit orchards, a single nucleotide in codon 43 of the rpsL, which is AAA in streptomycin-sensitive strain, was substituted for AGA causing an amino acid change from lysine to arginine. The resistant mechanism in all biovar 3 strains obtained in Korea was identified as a mutation of the rpsL gene.

• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.182-190
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• 2003

As DNA microarrays are widely used recently, the amount of microarray data is exponentially increasing. Until now, however, no domestic system is available for the efficient management of such data. Because the number of experimental data in a specific laboratory is limited, it is necessary to avoid redundant experiments and to accumulate the results using a shared data management system for microarrays. In this paper, a system named WEMA (WEb management of Micro Arrays) was designed and implemented to manage and process the microarray data. WEMA system was designed to include the basic feature of MIAME (Minimal Information About a Microarray Experiment), and general data units were also defined in the system in order to systematically manage the data. The WEMA system has three main features: efficient management of microarray data, integration of input/ouput data, and metafile processing. The system was tested with actual microarray data produced by a molecular biology laboratory, and we found that the biologists could systematically manage and easily analyze the microarray data. As a consequence, the researchers could reduce the cost of data exchange and communication.

• Development and Reproduction
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• v.13 no.4
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• pp.271-280
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• 2009

Human placenta is abundant source of adult stem cells. Especially, amniotic epithelial cells have stem cell characteristics, expressing surface markers normally present on embryonic stem cells and germ cells. However, culturing and expanding amniotic epithelial cells in vitro without feeder cells are difficult due to endogenous characteristics of epithelial cells. In the present study, amniotic epithelial cells are isolated and proliferated in several passages by applying dithiothreitol and a Rho-associated kinase inhibitor in culture media. The cultured amniotic epithelial cells showed the epithelial and stem cell characteristics. In conclusion, human placenta-derived amniotic epithelial stem cells can be a major source of stem cells for medical treatment of various diseases without any controversial issues.

• Journal of Information Management
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• v.40 no.1
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• pp.217-234
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• 2009

In computer-based virtual lab, a bioscience researcher who wants to obtain bio information first uses a biodiversity-related database to retrieve information on species, ecology and distribution of an organism. The researcher also needs to access gene/protein databases such as GenBank or PDB to find information on the organism's genetic sequence and protein structure. Furthermore, the researcher should search for academic papers containing the information on the organism so that his research is based on comprehensive and accurate information. This series of activities often undermines research efficiency as it takes a lot of time and causes inconvenience on the part of researchers. To solve such inconvenience, we analyzed various methods for integrated search and chosen schema integration. In addition, we analyzed each databases and extracted metadata for designing schema integration. This paper introduces a biological information retrieval system(BIRS) using schema integration and it's interface that will increase research efficiency for bioscience.

• Development and Reproduction
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• v.12 no.2
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• pp.133-139
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• 2008

The eggs of Luciogobius grandis attached beneath the small stone were collected at Ocheon-dong, Yeosu-city from February to May, 2006. We carried them to the laboratory of Chonnam National University to investigate their development. The fertilized eggs were elliptical in shape (mean long axis: $2.06{\pm}0.23\;mm$; mean short axis: $0.74{\pm}0.04\;mm$) and transparent. There were filaments on the egg membrane. Their hatching was occurred at 120hrs 54mins after the morula stage at $18.4{\sim}21.0^{\circ}C$ (mean $19.4^{\circ}C$). The newly hatched larvae were $3.30{\pm}0.07\;mm$ (n=30) in total length (TL), with $34{\sim}36$ myotomes, and their mouth and auns were already open. Their melanophores were appeared over the gas globule, around the anus and a part of caudal peduncle. At 9 days after hatching, the larvae was $5.06{\pm}0.18\;mm$ (n=30) in TL and transformed to postlarval stage with yolk absorption. At 29 days after hatching, the larvae attained full fin ray count and reached the juvenile stage with $11.46{\pm}0.12\;mm$ (n=30) in TL.

• Development and Reproduction
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• v.10 no.1
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• pp.41-45
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• 2006

The spawning behavior of Liobagrus obesus was observed at Kumgang river, Yeongdong-gun, Chungcheongbuk-do from Apirl to July 2004. The fertilized eggs collected by dip net and skimming net were carried to the laboratory of Chonnam National University, and then egg, larvae and juvenils development were studied. Hatching of the embryo began about at 225 hrs 15 mins after morula stage in water temperature of $19.5{\sim}24.9^{\circ}C$(mean $22.8^{\circ}C$). The newly-hatched larvae were $7.30{\sim}7.90mm$(mean 7.66mm) in total length (TL), their mouth and anus were already opened with 14+28=42 myotomes. Sixteen days after hatching, the postlarvae were $13.00{\sim}14.05mm$(mean 13.48mm) TL, the yolk sac was completely absorbed. The juvenile stage was reached when all fin-rays were formed at 24 days after hatching, and $15.31{\sim}17.20mm$(mean 16.31mm) TL.

• Development and Reproduction
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• v.10 no.1
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• pp.47-54
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• 2006

The Tridentiger obscurus were collected of Ocheon-dong and Dolsan-do in Yeosu from Apirl to July 2003, and were carried to the laboratory to investigate their development of spawning habit, egg development, larvae and juveniles. The fertilized eggs were measured $0.86{\sim}1.07{\times}0.53{\sim}0.74\;mm$ in diameter. Hatching of the embryo began about 154 hrs 40 mins after fertilization in water temperature of $18.4{\sim}23.2^{\circ}C$(mean $21.2^{\circ}C$). The newly-hatched larvae were $2.72{\sim}2.87mm$(mean 2.83mm) in total length (TL), their mouth and anus were opened, and the yolk sac was completely absorbed. At 21 days after hatching, the postlarvae were $5.32{\sim}7.23mm$(mean 6.02mm) TL, and the tip of the caudal notochord was flexed $45^{\circ}$ upward. The juveniles stage was reached when all fin-rays were formed at 45 day after hatching, and $11.62{\sim}14.32mm$(mean 13.45mm) TL.

• Journal of Plant Biotechnology
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• v.38 no.2
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• pp.125-129
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• 2011

Environmental risk assessment (RA) is essential prior to the environmental release of GM crops. RA, however, costs at least 7 to 15 million US dollars and requires several years to complete field tests. Therefore, it is strongly suggested that developers of GM crops must consider all criteria for RA at the beginning stage of the development if it aims for commercialization. Previous review papers have pointed out that the "death valley" for the commercialization of GM crops is the screening stage of early GM events since many candidates are given up due to insufficient data on the molecular characterization of a GM event such as inserted gene's copy number, position of inserted site of a chromosome, flanking sequence of recombinant T-DNA, rearrangement of chromosome, and knock out of endogenous gene of host plant. Recently, Rural Development Administration (RDA) in South Korea has launched a Grand National Project named as "Next Generation of BioGreen 21 Project" from 2011 to 2020 and research funding for the development of global GM crops has been allocated to accelerate the commercialization of GM crops. In this regard, I strongly suggest that researchers involved in the development of GM crops for commercialization must conduct RA by themselves at the screening stage of pre-GM event based on the data for molecular characterization.

• Development and Reproduction
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• v.5 no.1
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• pp.59-71
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• 2001

Since the first radioimmunoassay (RIA) was developed in 1970s, many conventional RIAs and non-isotopic immunoassays (NIA) had been developed in which the degree of precision, accuracy, specificity and practicability have progressively increased. Recently ultrasensitive assay method at femtogram to determine testosterone in serum, saliva and feces is required for the study of sexual dysfunctions in male and female, monitoring the psychological stress and conditions, aging process such as menopause and partial androgen deficiency in aging male, the hormonal changes of small experimental animals etc. This review discussed the recentd evelopments of steroid assay methods, based upon the testosterone assay results of authors far 20 years, and the problems associated the assay set-up, the characterizations and applications of the established procedures, and desifls of assay, reliablity criteria, and the practical aspects of assay set-up and application, based upon the data of the authors. The present study demonstrates the general problems methods to be consider in order to set up the highly sensitive assay methods and to increase the assay quality and the necessity of assay quality control program. To improve the assay quality of each laboratory and to compare the assay results in homeland, the national QC programs should be organized.

• Development and Reproduction
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• v.4 no.1
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• pp.115-123
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• 2000

A few enzymeimmunoassay (EfA) for testosterone (T) have been reported but was not suitable for all biological samples. The present study was designed to develop a rapid, ultrasensitive EIA and to apply this technique for study the physiological changes of T in biological samples. Saliva samples were collected at 06:00～09:00 hour during one menstrual cycle from 18 normally menstruating women and on 09:00～10:00 hour from 20 normal men. The present study shows an established EIA for testosterone, using horseradish peroxidase (HRP), which was covalently bonded to testosterone-3-carboxymethyloxime (T-3-CMO). One batch of T-antisera was also covalently linked to microcrystalline cellulose particles by a mixed anhydride method in order to facilitate separation of bound and free steroids. The established EIA was validated in terms of sensitivity, accuracy, specificity, precisions etc., comparing with conventional radioimmunoassay. The sensitivity of the established EIA was less than 25 pg/tube. The correlation coefficients between the expected T-values and observed T-values measured by EIA or RIA were r=0.985 and r=0.941 respectively. The cross reactivity of antiserum in EIA was a little higher than that of RIA, especially by 5 ${\alpha}$-DHT. The intra- and inter-assay precisions of the present EIA were similar to those of RIA. The present study also demonstrates that the normal T-values in saliva of Korean male ＆ female samples are 265.65${\pm}$15.80 pmol／l and 109.74${\pm}$ 12.01 pmol／l, respectively. The present EIA seems to be established and suitable for use in the endocrinological studies. The advantages of this EIA system also might make the present T-EIA an ideal procedure for use in a routine assay of ordinary laboratory with a conventional spectrophotometer.