• Korean journal of applied entomology
• /
• v.36 no.3
• /
• pp.277-282
• /
• 1997

Chemosterilant effect of chlorpyrifos-methyl (CPM) on the beet armyworm, Spodoptera e.rigua (Hubner) was investigated, using topical application. Egg fecundity and fertility were analyzed in the adults reared from the fifth instar larvae which were treated with sublethal doses of CPM. Though CPM reduced fecundity a little, it gave significant negative effect on egg fertility in a dose-dependent manner. Genetic analysis was performed by reciprocal crosses between treated (100 Wgllarva) and untreated individuals and showed a dominant lethal effect of CPM on egg fecundity and fertility. This results indicate that chlorpyrifos-methyl may act as a chemosterilant as well as a well-known neurotoxicant, and suggest that it can be used in genetic control program.

• Fisheries and Aquatic Sciences
• /
• v.13 no.2
• /
• pp.112-117
• /
• 2010

Altered mRNA expression of two metallothionein isoforms (MT-IA and MT-IB) in response to acute heavy metal exposure was examined in mud loach, Misgurnus mizolepis, fry using a real-time RTPCR assay. Sublethal exposure (1 or 5 ${\mu}M$) to Cd, Cr, Fe, Mn, Ni, and Zn resulted in highly variable transcriptional responses of the two MT isoforms to the heavy metal ions, including upregulation, a steady state, and downregulation. Overall, the most potent inducer of both MT isoforms was Cd (up to 6-fold). Another exposure experiment using a series of doses of Cu revealed that the stimulation patterns of the two MT isoforms differed: MT-IA transcription was soon saturated at higher concentrations (about 2-fold at 1-4 ${\mu}M$ of Cu), whereas the activation of MT-IB was more dependent on the treatment dose (increased up to 5-fold at 3 ${\mu}M$). The isoform-specific allotment of constitutive and inducible functions was not as clear in fry as in adult tissues. Coordinated interaction between the MT-IA and MT-IB isoforms was hypothesized based on the finding that MT-IA represented a primary action under 'less stressful' or 'sublethal' conditions, whereas the activation of MT-IB became important under 'more stressful' or 'lethal' circumstances in this species.

• Applied Biological Chemistry
• /
• v.35 no.5
• /
• pp.367-374
• /
• 1992

This study was performed to investigate effects of probable detoxifying enzyme activity and toxicity by pesticides and their combinations in the fresh water fish. Seven pesticides including IBP, isoprothiolane, cartap, ridomil, chlorothalonil, captafol and endosulfan were subjected to investigate for their acute toxicites and synergism possibilities. The $LC_{50}$ value of endosulfan was the lowest at showing 0.0079 ppm and that of metalaxyl was the highest as showing 40 ppm over. The synergism effects of relative pesticides were observed in the combinations of isoprothiolane+IBP and isoprothiolane+cartap. The changes of glycogen contents in fish liver were assayed for 5 pesticides and its highest inhibition effect of glycogen showed in IBP treated fish. The activity of probable detoxifying enzymes including carboxylesterase (CE), glutathion S-transferase (GST) and lactate dehydrogenase (LDH) were assayed in carp liver at dose of sublethal concentrations. Effects of pesticides on changes in each enzyme activities were as follows: carboxylesterase (CE) activities were the highest in IBP and gtutathion S-transferase (GST) activities were the highest in iosoprothiolane+IBP. Both activities of carboxylesterase (CE) and glutahtion S-transferase (GST) were increased by 5 chemicals. The highest LDH activity showed in isoprothiolane treated fish, while the lowest activity was observed in isoprothiolane+cartap. Sublethal exposure to cartap and isoprothiolane+cartap in carp exerted various effects on LDH activity.

• Korean journal of applied entomology
• /
• v.35 no.1
• /
• pp.52-57
• /
• 1996

This experiment was carried out to evaluate the effect of sublethal doses of BPMC, etofenprox,and buprofezin on N. lugens. and its predator C. lividipennis. Buprofezin was found to be the most toxic to N. lugens and the most safe to C. lividipennis among the three insecticides, based on LD50 values. Selective toxicity index calculated by dividing LDSo value of C. lividipennis by that of N. lugens indicated that buprofezin was very safe to C. lividipennis, showing selective toxicity of 2703.3. Longevity and fecundity of N. lugens treated with LDIU and LDm of buprofezin and BPMC were not significantly different with those of untreated brown planthoppers. However, egg hatchability' of N. lugens was greatly reduced when treated with LDm of buprofezin, having the highest inhibition rate of 17.7%. Hatchability of eggs from insects treated with BPMC was similar to that of control. The oviposited peak of treated hoppers appeared late as compared to the untreated which showed the peak at early part of the ovipositional period. The longevity and fecundity of C. lividipennis treated with BPMC were significantly reduced as compared with the untreated. Etofenprox also induced fecundity reduction when treated with LDlo, and LDm. However, C. lividipennis treated with sublethal doses of buprofezin showed no redution in logevity and fecundity. From these results, it may be said that buprofezin can be used to control brown planthopper without disrupting of C. lividipennis population in the rice field.

• The Korean Journal of Pesticide Science
• /
• v.9 no.4
• /
• pp.374-379
• /
• 2005

Sublethal dose effect of imidacloprid on green peach aphid (Myzus persicae) was investigated. Nymphs of green peach aphid newly produced were counted on 4 days after sub-lethal dose treatment of imidacloprid. Numbers of nymph were not significantly different between $LC_1$ treatment and untreated control. Their numbers of nymph were 8.8 and 12.7 at $LC_1$ and untreated control, respectively. When they were tented at $LC_{10}$, $LC_{30}$ and $LC_{50}$. their numbers of newly produced nymph were 6.0, 5.1 and 3.9 and reduction rates were 52.7%, 59.8% and 69.3% at each treatment compare to untreated control. Reduction rates of newly laid nymph were proportional to the concentrations of imidacloprid treated. Repellent effect of aphid to imidacloprid was bigger in dipping than in watering method. Secretion amount had negative correlation with imidacloprid concentration in dipping method and suppression of secretion went up to 96%. In watering method, amount of secretion did not show any difference between insecticide concentration, but suppression, compared to untreated control, was over 97%.

• Journal of Yeungnam Medical Science
• /
• v.4 no.1
• /
• pp.89-96
• /
• 1987

Carbon tetrachloride and Dimethylnitrosamine, both potent hepatotoxic agents, affect the hepatic lobules with fatty changes and central necrosis, and hemorrhagic necrosis. To study the effects on morphologic changes of the hepatic lobules in cases of single and repeated treatment of both hepatotoxins, sublethal doses of carbon tetrachloride, 0.4ml/kg, and dimethylnitrosamine, 40mg/kg of rats were given intraperitoneally single, twice and triple. With interval of 3 days, and the results were as follows : 1. The fatty changes and central necrosis of the hepatic lobules were milder and more quickly disappeared in the rats with twice or triple treatment than single administration of carbon tetrachloride, and regenerative changes of hepatic and sinusoidal cells achieved fater in the rats with repeated administration of carbon tetrachloride than those with single treatment. 2. The hemorrhagic necrosis of the hepatic lobules was not significantly influenced by the times of DMN treatment, but the hyperplastic changes showed more active to animals, with multiple administration of DMN.

• The Journal of Korean Medicine
• /
• v.16 no.2 s.30
• /
• pp.299-311
• /
• 1995

The studies were investigated in the coma time and the survival time induced by KCN, the duration of breathing after decapitation, the survival time following ligation of both common carotid arteries and the survival time after it is treated for normobaric bypoxia with a nitrogen gas, a carbon dioxide gas or a vaccum in mice. The results were as follows: 1. In histotoxic anoxia, Moschus(0.4mg／kg, p.o) demonstrated a protective effect on coma induced by a sublethal dose of KCN(1.8mg／kg, i.v.) in mice. 2. Mice subjected to a lethal dose of KCN(3.0mg／kg, i.v.) did not die by administration of Moschus. 3. Moschus was significantly extended the duration of breathing after decapitation in mice. 4. Moschus showed a significant extension of survival time in mice following ligation of both common carotid arteries. 5. In the normobaric hypoxia with a nitrogen gas, Moschus showed a significant extension of survival time in mice. 6. In the normobaric hypoxia with a carbon dioxide gas, Moschus showed a significant shortness of survival time in mice. 7. In the normobaric hypoxia with a vaccum, Moschus showed a significant extension of survival time in mice. From the above results, it is suggested that Moschus demonstrated protective effects on the brain damages induced by cerebral anoxia.

• Korean Journal of Environmental Agriculture
• /
• v.8 no.1
• /
• pp.47-54
• /
• 1989

This study was conducted to investigate insecticide toxicities to a honeybee, Apis cerana F. being raised in Korea and its detoxifying enzyme activities. In order to determine the appropriate usage of insecticides, median effective dose and detoxifying enzyme activities to seven insecticides were observed. Various detoxifying enzymes, including microsomal oxidases, glutathione S-transferases, esterases, and DDT-dehydrochlorinase were assayed in the midguts of adult worker bees as the enzyme source. Of the insecticides used, $LC_{50}$ value in DDT treatment was the highest as 19ppm, and that in EPN treatment was the lowest as 0.75ppm. Sublethal exposures of honeybees to various insecticides had some effects on microsomal enzyme activities. Aldrin epoxidase activity was inhibited by malathion and demeton S-methyl treatment. N-demethylase activity was induced by carbaryl treatment. Of the glutathione S-transferases, aryltransferase(DCNB conjugation) activity was significantly induced by diazinon, and moderately induced by malathion. Of the esterases, ${\alpha}-NA$ esterase activity was moderately inhibited by malathion and permethrin. Carboxylesterase and acetylcholinesterase activity were not affected by the sublethal exposure of honeybee to the insecticides. Sublethal exposure of honeybee to the insecticides had no effect on DDT- dehydrochlorinase activity, except carbaryl, malathion and demeton S-methyl were inhibited.

• Toxicological Research
• /
• v.3 no.2
• /
• pp.89-96
• /
• 1987

To test the efficacies of thiosulfate in cyanide poisoning with or without oxygen, after the administration of sublethal dose of potassium cyanide, serial arterial blood samples were collected during 60 minutes in 15 rabbits. Cyanide ion concentrations were measured by Conway cell microdiffusion method, and arterial oxygen tensions were also observed. Comparison of elimination constants showed that arterial blood cyanide ion concentration decreased most rapidly in the thiosulfate with oxygen-administered group. The elimination of cyanide ion by the action of thiosulfate in acutely poisoned rabbit accelerated probably due to oxygen and elimination pattern seems to occur by first-order elimination kinetics.

• Toxicological Research
• /
• v.17 no.4
• /
• pp.287-296
• /
• 2001

The acute oral LD5O toxicity values of isazofos, pyraclofos, diazinon and methomyl were determined for Japanese quail based on OECD guideline. The $LD_{50}$ of isazofos, pyraclofos and diazinon was 16.26 mg/kg, and 7.11mg/kg body weight In female respectively. And the $LD_{50}$ of each chemical in male was 21.44, 35.64, 8.28 mg/kg body weight respectively. Diazinon was the most susceptible compounds to Japanese quail in both sexes. The $LD_{50}$ of methomyl was 21.24 mg/kg body weights in female, and 28.28 mg/kg body weight in male respectively. Diazinon, isazofos and methomyl were more toxic In the female than male. The symptoms of poisoning were similar in quails administrated with each chemicals. The clinical sign in Japanese quail were ataxia, salivation, diarrhea, ruffled feather and convulsion at dead point. There were severe hemorrhage and catarrhal inflammation from duodenum to ileum In all compounds. In Japanese quail treated with organophosphorus and carbamate compounds, brain acetylcholinesterase was inhibited by 88-96. The recovery was not observed after 5 h in sublethal dose.