• Journal of Preventive Medicine and Public Health
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• v.23 no.3 s.31
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• pp.358-368
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• 1990

To investigate the possibility of utilizing of sister chromatid exchange(SCE) analysis in lymphocytes as an indicator which could evaluate the effects of mutagenicity after in vivo exposure to hexavalent chromium, this study was conducted using some of chromium plating workers occupationally exposed to hexavalent chromium, chromium trioxide ($CrO_3$) in Taegu city. The study population was 12 Cr platers with perforation of nasal septum, 12 Cr platers without perforation of nasal septum and 20 controls. The SCE in peripheral blood lymphocytes of the subjects was analyzed and blood chromium concentration was estimated using the atomic absorption spectrophotometer (IL551) equipped with furnace atomizer (IL755). The mean SCE frequencies for Cr platers with and without perforation of nasal septum were statistically higher than those for control. The difference in SCE frequencies by age, smoking habits were not statistically significant both in Cr platers and controls. There was no difference in SCE frequencies by career of Cr platers workers. In Cr platers, the correlation between the mean SCE frequencies and chromium concentration in blood was not statistically significant. Using the transformation $y=(sum\;SCE)^{\frac{1}{2}}+(sum\;SCE+1)^{\frac{1}{2}}$, when the data was studied by multiple regression, it appeared that the influence of the occupation was the most important. Age, smoking, occupation and CrB(blood chromium concentration) together explain only 32.3% of interpersonal variation on SCE. The results in this study suggest tt a genetic risk due to occupationally exposure to hexavalent chromium is clearly inferable and thus, SCE analysis in human lymphocytes may be used indicator of biological toxic effects of chromium. Further, populatio analysis stuies are required before SCE frequency can be used as a mutagenic indicator in human population.

• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.37-44
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• 2005

Microspores were isolated from pepper (Capsicum annuum L.) anthers by using a micro-blender and cultured in modified NLN medium at $25^{\circ}C$. The influence of pretreatment period at $32^{\circ}C$, adding the 2-hydroxynicotinic acid to a pretreatment medium, and co-pretreatment anthers with microscopes on the induction of embryo were examined. Globular and torpedo embryos were observed from 3 weeks after culture. Embryo development was not synchronized within culture. After 4 weeks in culture, in addition to globular and torpedo embryos, cotyledonary embryos were observed. Normal cotylodonary embryos developed into plantlets when transferred to a solid hormone free B5 medium containing $2\%$ sucrose. Embryo yields were significantly higher after 1- and 2-day pretreatment at $32^{\circ}C$. However the development of embryo ceased at the globular or heart stage. In contrast, embryo yields were lower after 3- to 6-day pretreatment at $32^{\circ}C$ and embryo developed at the cotyledonary stage. After adding the 2-hydroxynicotinic acid to anther pretreatment solution, embryo yields were slightly increased. However most embryos occurred were at the globular or heart stage. Co-pretreatment of microspores with anthers was deleterious for embryo induction and development. AS far as we know, this is the first report of success in obtaining high frequency of embryogenesis and plantlets formation from isolated microspores of pepper. Although the culture conditions have to be optimized further, this promising microspore culture system can be used for genetic transformation, selection for dominant and recessive traits as well as for the production of homozygous doubled haploid plants.

• Journal of Plant Biotechnology
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• v.50
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• pp.248-254
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• 2023

This study was conducted to establish an efficient plant regeneration system in 'Dayu', a Korean variety of Perilla frutescens developed for seed oil production, in conjunction with the previously studied variety 'Namcheon'. The healthiest callus was formed on the hypocotyl explants cultured on a medium containing 0.1 mg/L NAA and 0.5 mg/L BA, outperforming the leaf and cotyledon samples. In both dark and long-day conditions, Dayu consistently exhibited significantly higher shoot regeneration rates compared with Namcheon. The highest shoot regeneration rates in Dayu were observed from the hypocotyl explants cultured on 0.1 mg/L NAA and 0.5 mg/L BA media, with shoot regeneration rates of 84.4% and 86.7% under dark and long-day conditions, respectively. Various combinations of plant growth regulators were tested to establish the optimal shoot regeneration conditions for Dayu hypocotyl explants. The results demonstrated that the highest shoot regeneration rate (90%) was achieved when 0.5 mg/L of BA was added to the medium without NAA. Among the regenerated shoots, 70.5% were normal plants, while 19.3% were abnormal. The addition of NAA or an increase in its concentration led to a higher occurrence of abnormal plants. After the regenerated shoots were transferred to 1/2 MS medium, roots were observed within 10-15 days. By day 30, they had developed into complete plants. The results obtained from the regeneration experiments with the perilla variety Dayu can valuably inform molecular breeding reliant on transformation techniques such as genome-editing and genetic modification technology.