• Toxicological Research
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• v.11 no.2
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• pp.295-302
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• 1995

Menadione-ghitathione conjugate (MEN-SG), a metabolite of menadione, is known to be a redoxcycler in rat hepatocyte subcellular fraction. Therefore, it was assumed that MEN-SG could exert cytotoxlclty to ral platelets, another target tissue of menadione. We first synthesized MEN-SG, the identity of which was verified by mass, $^1{H}$-NMR and UV-visible spectra. In addition, the stability of MEN-SG was investigated in biological assay system. MEN-SG was degraded in a time-dependent manner in DMSO which had been used as a vehicle and thus, tris-HCl buffer was used as a vehicle of MEN-SG despite the low solubility in it. Perchloric acid as well as platelets itself did not affect the stability of MEN-SG. Our next attempt was the evaluation of cytotoxicity of MEN-SG in rat platelets. MEN-SG did not induce cytotoxicity to rat platelets measured by two different methods, LDH release and turbidity changes. The extents of oxygen consumption by MEN-SG in intact platelets were significantly lower than those by menadione, though it had been observed that oxygen consumptions by menadione and MENSG were similar in subcellular fractioas of platelets. These results suggest that MEN-SG is not toxic to rat platelets despite its redox cycling capacity and glutathione conjugation reaction of menadione could be regarded as a detoxification process.

• Toxicological Research
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• v.24 no.3
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• pp.219-225
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• 2008

A screening study of the acute toxicity of organic arsenics such as arsenobetaine and arsenocholine, a product of arsenic methylation metabolite, and inorganic arsenic was carried out to examine hematological and serum biochemical parameters in cynomolgus monkeys(Macaca fascicularis). We found soft and liquid feces, and vomiting in all treated groups with inorganic and organic arsenics. The monkeys in inorganic arsenic-treated group showed a significant increase in vomiting frequency compared with those in three organic arsenics-treated groups. These results suggest that inorganic arsenic might be more toxic than three other organic arsenics tested. The monkeys in inorganic arsenic-treated group showed a decrease in platelet and an increase in monocyte on day 4 and the monkeys in arsenocholine-treated group showed an increase in reticulocyte percentage on day 8. The monkeys in inorganic-treated group also showed decreases in AST and ALT values and the monkeys in arsenobetaine-treated group showed a decrease in AST value and an increase in T-CHO value. However, these hematological and biochemical changes were within the physiological ranges, showing that the single dose of inorganic and organic arsenics did not affect at least hematological and serum biochemical parameters. The present study of toxicity with single dose of arsenics provides valuable indicators for longer term study of toxicity of repeated doses of arsenics in primates.

• Korean Journal of Veterinary Research
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• v.34 no.4
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• pp.821-831
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• 1994

Phenytoin(PHT), a commonly prescribed anticonvulsant, has been known as a teratogen in experimental animals and human. However, PHT has strain-specific teratogenic effects for mice and human. Dimethyl sulfoxids(DMSO) has been known to antagonize the teratogenic effects of secalonic acid D, a toxic mold metabolite that has similar teratogenic effects to PHT. Therefore, this study was performed to examine the embryopathic effects of PHT in terms of treatment period and the antiteratogenic effect of DMSO in ICR mice. PHT(75mg/kg, BW) was administered intrapetitoneally on day 10, 10-11 and 10-12 of gestation with or without DMSO(2ml/kg, BW), and the fetal malformation was observed on day 18. Major malformation of fetuses treated with PHT on day 10, 10-11 and 10-12 of gestation was cleft palate, and the percentages of fetus with cleft palate were 14.5%, 31.7% and 51.7%, respectively. Also, there was a significant decrease of cleft palate from 51.7% in PHT alone group to 30.8% in PHT plus DMSO group. Our findings suggest that cleft palate is one of major malformation by PHT treatment in ICR mouse and DMSO has strong antiteratogenic effect.

• The Plant Pathology Journal
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• v.34 no.2
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• pp.126-138
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• 2018

Rice blast caused by Magnaporthe oryzae is a major disease. In the present study, we aimed to identify and evaluate the novel bacterial isolates from rice rhizosphere for biocontrol of M. oryzae pathogen. Sixty bacterial strains from the rice plant's rhizosphere were tested for their biocontrol activity against M. oryzae under in vitro and in vivo. Among them, B. amyloliquefaciens had significant high activity against the pathogen. The least disease severity and highest germination were recorded in seeds treated with B. amyloliquefaciens UASBR9 (0.96 and 98.00%) compared to untreated control (3.43 and 95.00%, respectively) under in vivo condition. These isolates had high activity of enzymes in relation to growth promoting activity upon challenge inoculation of the pathogen. The potential strains were identified based on 16S rRNA gene sequencing and dominance of these particular genes were associated in Bacillus strains. These strains were also confirmed for the presence of antimicrobial peptide biosynthetic genes viz., srfAA (surfactin), fenD (fengycin), spaS (subtilin), and ituC (iturin) related to secondary metabolite production (e.g., AMPs). Overall, the results suggested that application of potential bacterial strains like B. amyloliquefaciens UASBR9 not only helps in control of the biological suppression of one of the most devastating rice pathogens, M. grisea but also increases plant growth along with a reduction in application of toxic chemical pesticides.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.18 no.1
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• pp.18-22
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• 2018

Carbamoyl phosphate synthetase I (CPS1) deficiency is a rare autosomal recessive urea cycle disorder that causes hyperammonemic crisis. CPS1 is the first enzyme encoded by the CPS1 gene, which catalyzes the first step of the urea cycle. In CPS1 deficiency, ammonia, the toxic metabolite produced by the interruption of the urea cycle, is accumulated in the blood and brain, leading to hyperammonemic encephalopathy and irreversible brain damage. Here, we report a fatal case of neonatal-onset CPS1 deficiency in a 4-day-old girl presenting with recurrent seizures, who was revealed to be homozygous for c.1529delG ($p.Gly510Alafs^*5$).

• Korean Journal of Environmental Agriculture
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• v.7 no.2
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• pp.117-123
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• 1988

This study was initiated to understand the mechanism of selective toxicity of diazinon and carbofuran to killifish and loach. Conventional LC50 was calculated from fish test. IC50 with acetylcholinesterase activity was estimated using whole body and wet brain homogenate of the two fish species. Acetylcholinesterase activity of killifish was approximately twice as high as that of loach. The selective toxicity of diazinon to killifish and loach was partly (14 : 4) explained by the IC50 of diazoxon, a toxic metabolite of diazinon. IC50 of carbofuran also partly (14 : 3.4) contributed to the selectivity. These result suggested that the enzymatic method might be utilized as a screening tool for the chemicals affecting fish species of environmental concern with certain limitations which should be overcome in future studies.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2005.12a
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• pp.38-45
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• 2005

The egg bags of Korean salamander(Hynobius leechii) were collected from farmlands in Gyeongsangnam-do area. The assumed breeding time, numerical variation of embryos in each egg bag, mortality and the rates of abnormalities were investigated. The toxicity of benomyl, the metabolite carbendazim and BIC which were frequently spread in agricultural area and caused spontaneous embryonic malformation was investigated. The assumed breeding time between the end of February and the end of March has the difference about a month because of a habitat and it takes about 2 or 3 weeks from laying eggs to hatching. The length of each egg bag and the number of embryos were very varied in each area. It is due to geographical variation. Among egg bags in total study area, only 406 of egg bags(17.70% of total egg bags) developed all of embryos to normal larvae, and 78.49% of total embryos were normally developed. The patterns of spontaneous embryonic malformation were 26 species from A to Z and the abnormal patterns in individual were 8 species and above. the geographical differences about the abnormal pattern were identified and 11 habitats categorized 4 groups. The most frequent abnormality in Gyeongsangnam-do area is the dysplasia of external gill. The caudal dysplasia, abdominal blister and dysplasia of fin were also frequently observed. Individuals showing severe external defect were histologically studied and they showed retinal hypo-pigmentation, thyroid carcinoma, somatic muscular dysplasia, degeneration of cephalic neuron and various organ dysplasia. Benomyl and carbendazim were treated by 10pM$^{\sim}$10uM and BIC was treated by 1$^{\sim}$40ppm to know the effect of toxicity about toxic substance of salamander. After benomyl was treated, a survival rate was sharply dropped from 2 to 8 days. $LC_{100}$ identified in $1{\mu}M$, $LC_{50}$ identified between 100nM and $1{\mu}M$. $EC_{50}$ was assumed between 10nM and 100nM. The prevalent external malformation was abdomen swelled abnormally and histo-pathological effects were abdomen, neural tube and lens hernia. This suggests that benomyl is the toxicitic substance which inhibits the development of digestive system and nervous system. The result of treated carbendazim was similar to that of the treated benomyl. The survival rate is sharply dropped between 2 and 6 days. $LC_{100}$ was identified $1{\mu}M$ and $LC_{50}$ was identified between 10nM and 100nM. This shows that cabendazim has stronger lethal toxicity than benomyl. Ventral blister, eye dysplasia and cephalic dysplasia in the individual of external malformation mean that cabendazim affected nervous system much more than benomyl. Because the toxicity of BIC affected less in the beginning but affected more in the near hatching period, the period causing toxicity is somewhat different. $LC_{100}$ identified near 40ppm and $LC_{50}$ identified near 25ppm. The external defect shows mainly ventral blister and histo-pathological results show intestinal deformities. This result suggests the BIC inhibited strongly the development of digestive system. These abnormal developments may be caused by antimitotic action, inhibition of tubulin complex, destruction of microtubule, inhibitions of neurulation and closing of neural fold, and by the inhibition of movement of neural crest cells of benomyl. These abnormal developments may be caused by the rupture of epithelium, the loss of microtubule, the reduction of spindle size, the inhibition of spindle assembly formation, the destruction of spindle poles of carbendazim. These abnormal developments may be caused cytotoxicity by inhibition of the synthesis of a number of macromolecules and similar reaction the inhibition of benomyl.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2119-2128
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• 2017

Citrinin (CIT) is a toxic secondary metabolite produced by fungi belonging to the Penicillium, Aspergillus, and Monascus spp. This toxin has been detected in many agricultural products. In this study, a strain Y3 with the ability to eliminate CIT was screened and identified as Cryptococcus podzolicus, based on the sequence analysis of the internal transcribed spacer region. Neither uptake of CIT by cells nor adsorption by cell wall was involved in CIT elimination by Cryptococcus podzolicus Y3. The extracellular metabolites of Cryptococcus podzolicus Y3 stimulated by CIT or not showed no degradation for CIT. It indicated that CIT elimination was attributed to the degradation of intracellular enzyme(s). The degradation of CIT by C. podzolicus Y3 was dependent on the type of media, yeast concentration, temperature, pH, and initial concentration of CIT. Most of the CIT was degraded by C. podzolicus Y3 in NYDB medium at 42 h but not in PDB medium. The degradation rate of CIT was the highest (94%) when the concentration of C. podzolicus Y3 was $1{\times}10^8cells/ml$. The quantity of CIT degradation was highest at $28^{\circ}C$, and there was no degradation observed at 3$5^{\circ}C$. The study also showed that acidic condition (pH 4.0) was the most favorable for CIT degradation by C. podzolicus Y3. The degradation rate of CIT increased to 98% as the concentration of CIT was increased to $20{\mu}g/ml$. The toxicity of CIT degradation product(s) toward HEK293 was much lower than that of CIT.

• Korean Journal of Weed Science
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• v.17 no.2
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• pp.199-206
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• 1997

Chlorsulfuron, an acetolactate-synthase-inhibiting sulfonylurea herbicide, induces many metabolic and physiological changes in susceptible plants. The objective of this study was to determine to what extent chlorsulfuton-induced phytotoxicity was due to a shortage of final products(the branched-chain amino acids valine, leucine, and isoleucine) or to an accumulation of a toxic metabolite(2-ketobutyrate), or both, in a susceptible species. Chlorsulfuron-treated canola seedlings showed growth inhibition and injury symptoms that included chlorosis, downward leaf rolling, and accumulation of anthocyanins. Supplementation with valine, leucine, and isoleucine prevented the chlorsulfuron-induced growth inhibition and injury symptoms only partially, suggesting that factor(s) other than a shortage of the branched-chain amino acids also are involved in the phytotoxicity. Canola seedlings treated with 2-ketobutyrate showed reduced growth, but they showed different changes in metabolites than seedlings treated with chlorsulfuron. The results suggest that 2-ketobutyrate is not involved in chlorsulfuron-induced phytotoxicity. We conclude that chlorsulfuron-induced phytotoxicity is due at least in part to a shortage of branched-chain amino acids.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7195-7200
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• 2014

Background: The aim of this study was to evaluate how CYP2C19 affects icotinib and metabolite' exposure, and to determine whether the exposure and EGFR genotype influences survival time, tumor metastasis and adverse drug reactions. Materials and Methods: 274 NSCLC patients who accepted 125mg icotinib/t.i.d. were chosen from a phase III study. Blood samples were obtained in $672^{nd}$ ($4^{th}$ week) and $1,680^{th}$ hours ($10^{th}$ week), and plasma was used to quantify the concentration of icotinib and blood cells were sampled to check the genotypes. Clinical data were also collected at the same time, including EGFR genotypes. Plasma concentrations were assessed by HPLC-MS/MS and genotype by sequencing. All data were analyzed through SPSS 17.0 and SAS 9.2. Results: CYP 2C19 genotypes affected bio-transformation from icotinib to M24 and M26, especially in poor-metabolisers. Higher icotinib concentrations (>1000 ng/mL) not only increased patient PFS and OS but also reduced tumor metastasis. Patients with mutant EGFR experienced a higher median PFS and OS (234 and 627 days), especially those with the 19del genotype demonstrating higher PR ratio. Patients who suffered grade II skin toxicity had a higher icotinib exposure than those with grade I skin toxicity or no adverse effects. Liver toxic reactions might occur in patients with greater M20 and M23 plasma concentrations. Conclusions: CYP2C19 polymorphisms significantly affect icotinib, M24 and M26 exposure. Patients with mutant EGFR genotype and higher icotinib concentration might have increased PFS and OS and lower tumor metastasis. Liver ADR events and serious skin effects might be respectively induced by greater M20, M23 and icotinib concentrations.