• Journal of Microbiology and Biotechnology
• /
• 제25권10호
• /
• pp.1614-1620
• /
• 2015

Plasmid-cured derivative strains of Bacillus anthracis are frequently used in laboratory studies. Plasmid incompatibility, which does not increase the risk of chromosomal mutation, is a useful method for plasmid curing. However, in bacteria containing multiple plasmids, it often requires the sequential introduction of multiple, specific incompatibility plasmids. This lengthy process renders the traditional plasmid incompatibility method inefficient and mutation-prone. In this study, we successfully cured plasmids pXO1 and pXO2 from B. anthracis A16 simultaneously using only one recombinant incompatible plasmid, pKORT, to obtain a plasmid-free strain, designated A16DD. This method may also be useful for the simultaneous, one-step curing of multiple plasmids from other bacteria, including Bacillus thuringiensis and Yersinia pestis.

• 대한의생명과학회지
• /
• 제21권4호
• /
• pp.165-171
• /
• 2015

Microbial pathogens are responsible for most of the rapidly-spreading deadly infectious diseases against humans. Thus, there is an urgent need for efficient and rapid detection methods for infectious microorganisms. The detection methods should not only be targeted and specific, but they have to be encompassing of potential changes of the pathogen as it evolves and mutates quickly during an epidemic or pandemic. The existing diagnostics such as the antibody-based ELISA immunoassay and PCR methods are too selective and narrowly focused; they are insufficient to capture newly evolved mutant strains of the pathogen. Here, we introduce a fresh perspective on some new technologies, including aptamers and next generation sequencing for pathogen detection. These technologies are not in their infancy; they are reasonably mature and ready, and they hold great promise for unparalleled applications in pathogen detection.

• 대한한의학방제학회지
• /
• 제14권1호
• /
• pp.141-167
• /
• 2006

The genotoxicity of water extract of Bojungikkeehapdaechilki-tang was tested by In Vitro Chromosome Aberration Test. Bacterial Reverse Mutation Assay and Micronucleus test according to OECD Guidelines and KFDA Guidelines. The obtained results were as follows : 1. Chromosome Aberration Test: In Vitro Chromosome Aberration Test of Bojungikkeehapdaechilki-tang extracts was carried out using cultured Chinese hamster lung cells in the presence and absence of metabolic activation system(S-9 mix). No significant changes in the number of aberrant metaphases having structural and number of aberrations were detected in Bojungikkeehapdaechilki-tang extracts treated groups. 2. Bacterial Reveres Mutation Assay: Bojungikkeehapdaechilki-tang extracts was evaluated for its potential to induce reverse mutation in the histidine auxotroph strains of Salmonella typhimurium such as TA100, TA1535, TA98 and TAl537 and the tryptophan auxotroph strain of Escherichia coli WP2 uvrA. No significant changes in the number of revertant colonies compared to its negative control were detected in Bojungikkeehapdaechilki-tang extracts treated groups against all 5 strains. 3. Micronucleus test: Micronucleus test of Bojungikkeehapdaechilki-tang extracts were performed using specific pathogen free 7-week old male ICR mouse. No significant changes in the number of micronucleated polychromatic erythrocytes among 2000 polychromatic erythrocytes compared to negative control were detected in all Bojungikkeehapdaechilki-tang extracts treated groups. In summarized above-mentioned results, it is concluded that Bojungikkeehapdaechilki-tang extracts have not genotoxicity against In Vitro Chromosome Aberration Test, Bacterial Reverse Mutation Assay and Micronucleus test.

• 한국연초학회지
• /
• 제17권1호
• /
• pp.27-32
• /
• 1995

A new flue-cured tobacco mutant line BU 8832-85 was developed at Taegu Experiment Station, Korea Ginseng and Tobacco Research Institute in 1994. KF 8832-85 was resulted from a cross of flue-cured cultivars NC 95$\times$NC 2326, and developed by a pedigree system of breeding ; initial selection was made by plant type and resistance to bacterial wilt(BW) disease(heudomonas solanaceamm) in the F2 generation under the natural field conditions infested with the pathogen. One white flowered plant was occurred by spontaneous mutation in a certain line among the F3 generatioin while the others were pink. Six plants from the seeds by selfing were selected at the field infested with the pathogen among 240 populations with white flowering in the F4, KF 8832-85 was selected based on yield and leaf quality trials among 6 lines in Fs generation. BCF 8832-85 was compared with its Parent for certain agronomic and chemical characteristics at Taegu Experiment Station in 1993 and 1994. The results showed that KF 8832-85 have white flower, the stalk height was approximately that of NC 2326 but averaged about loom taller than NC 95. It produced ground suckers as much as NC 95, and did not breakdown leaf at the same as WC 2326. KF 8832-85 have high resistance to bacterial wilt disease. Yield of KF 8832-85 was 10 and 18% higher then that of NC 2326 and WC 95, respectively. Price per Kg was equal to that of NC 2326. The contents of nicotine and reducing sugar did not differ significantly from NC 95, while total nitrogen was significantly lower than NC 95. Therefore, the new mutant line is genetically stable for agronomic and chemical characteristics and provides a source of bacterial wilt disease resistance for use in breeding resistant flue-cured cultivars. Key words : Mutant line, White flower, Spontaneous mutation.

• Asian-Australasian Journal of Animal Sciences
• /
• 제16권9호
• /
• pp.1247-1253
• /
• 2003

Selection for increased milk production in dairy cows has often resulted in a higher incidence of disease and thus incurred a greater health costs. Considerable interests have been shown in breeding dairy cattle for disease resistance in recent years. This paper discusses the limitations of breeding dairy cattle for genetic resistance in six parts: 1) complexity of disease resistance, 2) difficulty in estimating genetic parameters for planning breeding programs against disease, 3) undesirable relationship between production traits and disease, 4) disease as affected by recessive genes, 5) new mutation of the pathogens, and 6) variable environmental factors. The hidden problems of estimating genetic and phenotypic parameters involving disease incidence were examined in terms of categorical nature, non-independence, heterogeneity of error variance, non-randomness, and automatic relationship between disease and production traits. In light of these limitations, the prospect for increasing genetic resistance by conventional breeding methods would not be so bright as we like. Since the phenomenon of disease is the result of a joint interaction among host genotype, pathogen genotype and environment, it becomes essential to adopt an integrated approach of increasing genetic resistance of the host animals, manipulating the pathogen genotypes, developing effective vaccines and drugs, and improving the environmental conditions. The advances in DNA-based technology show considerable promise in directly manipulating host and pathogen genomes for genetic resistance and producing vaccines and drugs for prevention and medication to promote the wellbeing of the animals.

• Biomolecules & Therapeutics
• /
• 제10권4호
• /
• pp.268-273
• /
• 2002

Mutagenic potential of HM10411 (recombinant human granulocyte colony stimulating factor) was evaluated by bacterial reverse mutation test, in vitro chromosome aberration test and in vivo micronucleus test. The bacterial reverse mutation test was performed using the histidine auxotroph strains of Salmonella typhimurium TA100, TA1535, TA98, TA1537 and tryptophan auxotroph strain of Escherichia coli WP2 uvrA. The negative results of the bacterial reverse mutation test suggest that HM10411 does not induce mutation, in the genome of Salmonella typhimurium and E. coli under the conditions used. In addition, it has little clastogenicity either in vitro chromosome aberration test or in vivo micronucleus test. For in vitro chromosomal aberration test, Chinese hamster lung(CHL) cells were exposed to HM10411 of 23, 46 or 92 $\mu\textrm{g}$/ml for 6 or 24 hours in the absence and for 6 hours in the presence of metabolic activation system. There was no significant increase in the number of aberrant metaphase in HM 10411-treated groups at any dose levels both in the presence and absence of metabolic activation system. The micronucleus test was carried out using specific pathogen free(SPF) 7-week old male ICR mice, The test item, HM10411 was intraperitoneally administered at 1150, 2300 or 4600 $\mu\textrm{g}$/kg once a day for 2 consecutive days. There was no significant increase in the frequencies of micronucleated polychromatic erythrocytes(PCEs) at any treated groups compared with negative control group. Therefore, these results demonstrate that the test item, HM10411, was not mutagenic under the condition of these studies.

• 혜화의학회지
• /
• 제10권2호
• /
• pp.1-10
• /
• 2002

In review of "invigorating spleen and supplementing qi" of clinical and experimental studies on malignant tumor, we obtained the conclusions as follows 1. Asthenic splenic qi is an important factor in mutation, occurrence and development of tumor. 2. The anti-tumor mechanism of "invigorating spleen and supplementing qi" is improvement of immune suveillance, controling cell proliferating period and enhancing body metabolism. 3. "Invigorating spleen and supplementing qi" is often used with "nourishing kidney" or "expelling pathogen" for treating cnacer. 4. In experimental studies, "invigorating spleen and supplementing qi" has effects on inhibiting occurrence and development of tumor, protecting mutation, inhibiting recurrence and metastasis, immune activity, enhancing metabolism, promoting bone marrow hemopoietic cell proliferation, increasing anti-tumor effect and protecting normal cells. 5. In clinical studies, "invigorating spleen and supplementing qi" has effects on prolonging the survival period of cancer patients, improving clinical symptoms and quality of life of cancer patients, degrading the side effects of western therapie(operation, chemotherapy and radiotherapy). 6. "Invigorating spleen and supplementing qi" is an extensive discipline of syndrome differentiation used to inhibit occurence, development, recurrence and metastasis.

• The Plant Pathology Journal
• /
• 제39권5호
• /
• pp.417-429
• /
• 2023

Ralstonia solanacearum species complex (RSSC) is a soil borne plant pathogen causing bacterial wilt on various important crops, including Solanaceae plants. The bacterial pathogens within the RSSC produce exopolysaccharide (EPS), a highly complicated nitrogencontaining heteropolymeric polysaccharide, as a major virulence factor. However, the biosynthetic pathway of the EPS in the RSSC has not been fully characterized. To identify genes in EPS production beyond the EPS biosynthetic gene operon, we selected the EPS-defective mutants of R. pseudosolanacearum strain SL341 from Tn5-inserted mutant pool. Among several EPSdefective mutants, we identified a mutant, SL341P4, with a Tn5-insertion in a gene encoding a putative NDP-sugar epimerase, a putative membrane protein with sugar-modifying moiety, in a reverse orientation to EPS biosynthesis gene cluster. This protein showed similar to other NDP-sugar epimerases involved in EPS biosynthesis in many phytopathogens. Mutation of the NDP-sugar epimerase gene reduced EPS production and biofilm formation in R. pseudosolanacearum. Additionally, the SL341P4 mutant exhibited reduced disease severity and incidence of bacterial wilt in tomato plants compared to the wild-type SL341 without alteration of bacterial multiplication. These results indicate that the NDP-sugar epimerase gene is required for EPS production and bacterial virulence in R. pseudosolanacearum.

• 한국식물학회:학술대회논문집
• /
• 한국식물학회 1999년도 제13회 식물생명공학심포지움 New Approaches to Understand Gene Function in Plants and Application to Plant Biotechnology
• /
• pp.41-44
• /
• 1999

Magnaporthe grisea (Hebert) Barr (anamorph: Pyricularia grisea) is a typical heterothallic Ascomycete and the causal agent of rice blast, one of the most destructive diseases on rice (Oryza sativa L.) worldwide. The interactions between cells of the pathogen and those of the host involve a complex of biological influences which can lead to blast disease. The early stages of infection process in particular may be viewed as a sequence of discrete and critical events. These include conidial attachment, gemination, and the formation of an appressorium, a dome-shaped and melanized infection structure. Disruption of this process at any point will result in failure of the pathogen to colonize host tissues. This may offer a new avenue for developing innovative crop protection strategies. To recognize and capture such opportunities, understanding the very bases of the pathogenesis at the cellular and molecular level is prerequisite. Much has been learned about environmental cues and endogenous signaling systems for the early infection-related morphogenesis in M. grisea during last several years. The study of signal transduction system in phytopathogenic filamentous fungi offers distinct advantages over traditional mammalian systems. Mammalian systems often contain multiple copies of important genes active in the same tissue under the same physiological processes. Functional redundancy, alternate gene splicing, and specilized isoforms make defining the role of any single gene difficult. Fungi and animals are closely related kingdoms [3], so inferences between these organisms are often justified. For many genes, fungi frequently possess only a single copy, thus phenotype can be attributed directly to the mutation or deletion of any particular gene of interest.

• 한국식물학회:학술대회논문집
• /
• 한국식물학회 1985년도 워크샵 및 심포지엄 북한산국립공원의 식생
• /
• pp.19-22
• /
• 1985

Magnaporthe grisea (Hebert) Barr (anamorph: Pyricularia grisea) is a typical heterothallic Ascomycete and the causal agent of rice blast, one of the most destructive diseases on rice (Oryza sativa L.) worldwide. The interactions between cells of the pathogen and those of the host involve a complex of biological influences which can lead to blast disease. The early stages of infection process in particular may be viewed as a sequence of discrete and critical events. These include conidial attachment, gemination, and the formation of an appressorium, a dome-shaped and melanized infection structure. Disruption of this process at any point will result in failure of the pathogen to colonize host tissues. This may offer a new avenue for developing innovative crop protection strategies. To recognize and capture such opportunities, understanding the very bases of the pathogenesis at the cellular and molecular level is prerequisite. Much has been learned about environmental cues and endogenous signaling systems for the early infection-related morphogenesis in M. grisea during last several years. The study of signal transduction system in phytopathogenic filamentous fungi offers distinct advantages over traditional mammalian systems. Mammalian systems often contain multiple copies of important genes active in the same tissue under the same physiological processes. Functional redundancy, alternate gene splicing, and specilized isoforms make defining the role of any single gene difficult. Fungi and animals are closely related kingdoms [3], so inferences between these organisms are often justified. For many genes, fungi frequently possess only a single copy, thus phenotype can be attributed directly to the mutation or deletion of any particular gene of interest.