• Environmental Analysis Health and Toxicology
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• v.25 no.2
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• pp.131-143
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• 2010

We performed the tests of acute and subchronic inhalation toxicity of methyl formate, which has limited toxicological data in spite of its widespread use and enhanced hazard consequent on its high volatility. The median lethal concentration ($LC_{50}$) was evaluated to be above 5,000ppm(12.27 mg/L). In the test with subchronic inhalation, there are no deaths, but with reduction of body weight, food intake, organ weight by exposure to 400 (0.98 mg/L) and 1,600 (3.92 mg/L) ppm, dose-dependently. There were statistical differences in some hematological and blood biochemical parameters as compared to control (e.g. neutrophile and lymphocyte in the 1,600 ppm group, calcium and A/G in 1,600 ppm group). Methyl formate under the exposure of 1,600 ppm showed the respiratory findings with nasal, it was confirmed that the chemical has respiratory hazard with 1,600 ppm inhalation exposure, induces nasal epithelial atrophy, olfactory cell degeneration/regeneration and the contraction of olfactory cells, etc. According to the notification with Ministry of Labor (No. 2009-68) for classification, labeling and MSDS of chemicals, it is suggested for methyl formate to be classified as category 4 in acute (10.0$4\leq20.0$ mg/L), category 2 (0.2$\leq$1.0 mg/L/6h, 90 days) in specific target organ-repeated exposure.

• Journal of Food Hygiene and Safety
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• v.33 no.3
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• pp.214-219
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• 2018

The present study was carried out to investigate the acute oral toxicity of Chamaecyparis obtusa (C. obtusa) essential oil in ICR male and female mice. Acute oral treatment with C. obtusa essential oil did not reveal any sign of toxicity or mortality in treated mice. Mouse body weights were not affected after single oral administration of C. obtusa essential oil during the 14-day observation period. In the hematological and blood biochemical analysis, all parameters of the treated group with 2,000 mg/kg body weight of the essential oil were not significantly different those of the control group. Therefore, the lethal dose 50 of the essential oil was estimated to be greater than 2,000 mg/kg body weight in mice, which indicated that the essential oil is non-toxic. In conclusion, this study suggests that C. obtusa essential oil orally safe ICR mice.

• Journal of Veterinary Science
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• v.21 no.6
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• pp.88.1-88.13
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• 2020

Background: Listeria monocytogenes is a gram-positive bacterium that causes listeriosis mainly in immunocompromised hosts. It can also cause foodborne outbreaks and has the ability to adapt to various environments. Peptide uptake in gram-positive bacteria is enabled by oligopeptide permeases (Opp) in a process that depends on ATP hydrolysis by OppD and F. Previously a putative protein Lmo2193 was predicted to be OppD, but little is known about the role of OppD in major processes of L. monocytogenes, such as growth, virulence, and biofilm formation. Objectives: To determine whether the virulence traits of L. monocytogenes are related to OppD. Methods: In this study, Lmo2193 gene deletion and complementation strains of L. monocytogenes were generated and compared with a wild-type strain for the following: adhesiveness, invasion ability, intracellular survival, proliferation, 50% lethal dose (LD₅₀) to mice, and the amount bacteria in the mouse liver, spleen, and brain. Results: The results showed that virulence of the deletion strain was 1.34 and 0.5 orders of magnitude higher than that of the wild-type and complementation strains, respectively. The function of Lmo2193 was predicted and verified as OppD from the ATPase superfamily. Deletion of lmo2193 affected the normal growth of L. monocytogenes, reduced its virulence in cells and mice, and affected its ability to form biofilms. Conclusions: Deletion of the oligopeptide transporter Lmo2193 decreases the virulence of L. monocytogenes. These effects may be related to OppD's function, which provides a new perspective on the regulation of oligopeptide transporters in L. monocytogenes.

• Toxicological Research
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• v.26 no.4
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• pp.293-300
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• 2010

tert-Butyl acetate (TBAc) is an organic solvent, which is commonly used in architectural coatings and industrial solvents. It has recently been exempted from the definition of a volatile organic compound (VOC) by the Air Resources Board (ARB). Since the use of TBAc as a substitute for other VOCs has increased, thus its potential risk in humans has also increased. However, its inhalation toxicity data in the literature are very limited. Hence, inhalation exposure to TBAc was carried out to investigate its toxic effects in this study. Adult male rats were exposed to TBAc for 4 h for 1 day by using a nose-only inhalation exposure chamber (low dose, $2370\;mg/m^3$ (500 ppm); high dose, $9482\;mg/m^3$ (2000 ppm)). Shamtreated control rats were exposed to clean air in the inhalation chamber for the same period. The animals were killed at 2, 7, and 15 days after exposure. At each time point, body weight measurement, bronchoalveolar lavage fluid (BALF) analysis, histopathological examination, and biochemical assay were performed. No treatment-related abnormal effects were observed in any group according to time course. Based on those findings, the median lethal concentration ($LC_{50}$) of TBAc was over $9482\;mg/m^3$ in this study. According to the MSDS, the 4 h $LC_{50}$ for TBAc for rats is over $2230\;mg/m^3$. We suggested that this value is changed and these findings may be applied in the risk assessment of TBAc which could be beneficial in a sub-acute study.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.27-27
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• 2021

Yacon [Samallanthus sonchifolius (Poepp. & Endl.) H. Robinson], a member of Compositae plants, has sweet taste and crisp texture. Unlike other Andean root crops such as potato and sweet potato, the cultivation area of yacon has increased recently, since it is known to have large content of fructooligosaccharides (FOS). Since there are no yacon varieties bred in Korea, we have been trying to create new genetic resources using gamma-ray. The optimal gamma-ray dosage for mutation breeding in yacon was investigated. Crown bud and green bud of yacon were exposed to doses of gamma rays from 20 Gy to 80 Gy, and subsequently planted in a greenhouse. After 50 days of sowing, the survival rates and growth decreased rapidly at doses above 40 Gy, while all of crown bud individuals died above 60 Gy. The median lethal dose (LD50) of crown bud and green bud was 22.4 and 36.6 Gy, and the median reduction doses (RD50) for plant height, fresh weights, and tuberous root weight were 20-40 Gy, respectively. A dose of 20-40 Gy was found to be optimal for mutation breeding in yacon. Considering the growth factors, the optimum doses were determined to be within the range of 20-40 Gy for the selection of useful mutant lines. M2-M3 mutant lines were obtained from 20-60 Gy gamma-ray-irradiated M1 plants through clonal propagation. These mutant lines will be used for the development of a new variety of yacon plant with high FOS and no crack tuberous root.

• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.106-110
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• 2008

This study was designed to evaluate the single dose toxicity and the protective effect of water extract of Cordyceps militaris grown upon Protaetia dreujtarsis (CMPD extract) on liver damage on carbon tetrachloride ($CCl_4$)- induced acute hepatotoxicity in Sprague-Dawley (SD) rats. The CMPD extract was once administered orally to both sexes of rats at dose of 2,000, 1,000 and 500 mg/kg body weight, the recommended maximum limit dose for acute toxicity. Neither significant toxic signs nor death was observed during the observation period. These results indicate that $LD_{50}$(lethal dose of 50%) of CMPD extract is greater than 2,000 mg/kg body weight in SD rats. To investigate also the effect of hepatoprotection of CMPD extract, SD rats were orally treated with CMPD extract (50, 25 and 12.5 mg/kg body weight) or silymarin (25 mg/kg body weight) before and after administration of $CCl_4$ (2 mL/kg body weight, 20% $CCl_4$ in olive oil). Treatment with CMPD extract or silymarin could decrease the GPT (glutamic-pyruvic transaminase) and GOT (glutamic-oxaloacetic transaminase) levels in serum when compared with $CCl_4$-treated group. Therefore, the results of this study show that CMPD extract can be proposed to protect the liver against $CCl_4$-induced hepatic damage in rats.

• Journal of Veterinary Clinics
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• v.10 no.1
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• pp.111-130
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• 1993

Lead toxicity was evaluated in forty-five cats on a balanced diet, Treated with 0(control), 10, 100(low), 1, 000, 2, 000, and 4, 000(high) ppm of lead acetate orally on a body weight basis. The objectives were to establish toxic dosage level of leaf in cats, to characterize changes in behavior and clinical pathology, and to demonstrate what blood lead concentrations correlate with the known dosages of lead. Some high dose cats showed projectile vomiting, hyperactivity, and seizures. The growth rates did not appear to be altered in any of the dosed groups. Normal blood lead concentration in cats were lower than that of humans, dogs, and cattle. Blood lead concentrations of 3 to 20$\mu\textrm{g}$/100$m\ell$ could be termed a 'subclinical' range in the cat. Clinical lead toxicity in cats may have blood lead concentrations ranging 20 to 120$\mu\textrm{g}$/100$m\ell$. Zinc protoporphyrin concentrations were proportional to lead dosages and a significant ZPP elevation, greater than 50$\mu\textrm{g}$/100$m\ell$, may be indicative of clinical lead toxicity. The enzyme aminolevulinic acid dehydratase showed an inverss dose response relationship for all lead dosages and a significant ZPP elevation, greater than 50$\mu\textrm{g}$/100$m\ell$, may be indicative of clinical lead toxicity. The enzyme aminolevulinic acid dehydratase showed an inverse dose response relationship for all lead dosages and appears to be a good indicator of lead exposure in cats. Urinary aminolevuliruc acid concentrations generally increased with lead dosage, but individual values varied. Hair lead concentrations rose proportionately to lead dosages. Lead at least in high doses appears to inhibit chemotactic activity of polymorphonuclear cells and monocytes. No consistent dose response relationships were observed in hemoglobin, RBC, WBC, neutrophil, lymphocyte, monocyte, and eosinophil counts. There were no consistent dose related changes in total protein, plasma protein, BUN, and ALT values. Reticulocyte counts did not increase significantly in most lead dosage levels, and are probably of little value in diagnosing lead toxicity in cats. The fact that no significant changes were found in nerve conduction velocities may support that there was no segmental demyelination resulting from lead ingestion. The lethal dose in cats appear to range from 60 to 150mg/kg body weight. A reliable diagnosis of lead poisoning can be made utilizing blood lead, ZPP, and ALAD, and hair lead.

• Fisheries and Aquatic Sciences
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• v.23 no.8
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• pp.20.1-20.18
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• 2020

Background: Olive flounder, Paralichthys olivaceus, is an economically important aquaculture species in Korea. Olive flounders have been heavily damaged by streptococcal infections every year and are treated with antibiotics. However, antibiotic abuse is causing the emergence of resistant strains, and to overcome this, research has shown that new antibiotics must be applied. Tylosin is a relatively safe antibiotic and has good activity against Gram-positive bacteria and mycoplasma. We studied the therapeutic effects and side effects of tylosin on Streptococcus parauberis-infected olive flounder. Methods: After artificial infection of olive flounder with S. parauberis SPOF18J3, an appropriate dose of tylosin was confirmed by intramuscular injection (I.M.) at 2.5, 5, 10, and 15 mg/kg, and oral administration at 10 and 20 mg/kg. After I.M. and oral administration dosing of tylosin, side effects were confirmed by serological analysis, histopathological analysis, and median lethal dose (LD₅₀) analysis at both an appropriate concentration and a high concentration. Statistical analysis was performed using one-way analysis of variance (ANOVA) and Tukey's test (p < 0.05). Results: The appropriate I.M. and oral administration concentration of tylosin administered to olive flounder infected with S. parauberis SPOF18J3 was found to be 10 mg/kg. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were showed not significantly different between the control group and the experimental groups. The histopathologic results showed mild inflammatory responses in muscle and tubular vacuolization and tubular atrophy appeared, but there were no significant differences between the groups. The LD₅₀ was confirmed to be 461 mg/kg. Conclusion: In this study, an effective treatment method was provided by verifying the treatment effects and side effects of tylosin in olive flounder infected with S. parauberis, which can be applied directly to aquaculture sites. In addition, these results may be used as a reference for evaluation required upon request to obtain approval for tylosin antibiotics as fishery antibiotics in Korea. After approval, it is possible that a fishery disease manager will be able to prescribe and sell the antibiotic tylosin.

• Journal of Ginseng Research
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• v.44 no.2
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• pp.222-228
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• 2020

Background: 20(S)-ginsenoside-Rg3 (C₄₂H₇₂O₁₃), a natural triterpenoid saponin, is extracted from red ginseng. The increasing use of 20(S)-ginsenoside Rg3 has raised product safety concerns. Methods: In acute toxicity, 20(S)-ginsenoside Rg3 was singly and orally administrated to Kunming mice and Sprague-Dawley (SD) rats at the maximum doses of 1600 mg/kg and 800 mg/kg, respectively. In the 26-week toxicity study, we used repeated oral administration of 20(S)-ginsenoside Rg3 in SD rats over 26 weeks at doses of 0, 20, 60, or 180 mg/kg. Moreover, a 4-week recovery period was scheduled to observe the persistence, delayed occurrence, and reversibility of toxic effects. Results: The result of acute toxicity shows that oral administration of 20(S)-ginsenoside Rg3 to mice and rats did not induce mortality or toxicity up to 1600 and 800 mg/kg, respectively. During a 26-week administration period and a 4-week withdrawal period (recovery period), there were no significant differences in clinical signs, body weight, food consumption, urinalysis parameters, biochemical and hematological values, or histopathological findings. Conclusion: The mean oral lethal dose (LD₅₀) of 20(S)-ginsenoside Rg3, in acute toxicity, is above 1600 mg/kg and 800 mg/kg in mice and rats, respectively. In a repeated-dose 26-week oral toxicity study, the no-observed-adverse-effect level for female and male SD rats was 180 mg/kg.

• FLOWER RESEARCH JOURNAL
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• v.16 no.3
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• pp.211-217
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• 2008

To build up data for mutation breeding of lily, sensitivity to irradiation of bulb, seed and pollen was investigated. The bulbs of seven cultivars including 'New Wave' were very sensitive to gamma rays. Non-irradiated bulbs produced plants with bloom as normal. However, irradiated bulbs showed retarded growth and did not flower. Bulbs of 'New Wave' and 'Tiny Dino' irradiated with 125Gy gamma rays survived, but their growth rate dropped considerably. Part or whole leaves of the other cultivars except 'New Wave' and 'Tiny Dino' withered. Moisture content of individual scale was 72~78% depending on cultivar. Bulblet formation from untreated scales was 100%. Among all irradiated scales only 'Siberia' scales showed 8.5% bulblet formation when irradiated with 50Gy gamma rays. Pollen germination as affected by gamma ray irradiation had no consistent tendency. When dosage of $F_1$ 'Augusta' seeds reached 300Gy, their survival ratio was drastically decreased. Bulblet formation in vitro was observed only in non-irradiated seeds. Lethal dose ($LD_{50}$) of seed was less than 100Gy. Height and width of $F_1$ 'Augusta' bulblets in vitro irradiated with gamma rays decreased as dosage increased regardless of the culture method. The percentage shoot formation was 100% in non-irradiated bulblets and 15~60% in irradiated ones.