OBJECTIVETo evaluate the toxicity of photoactivated insecticide K-01 to the larvae of Aedes albopictus and observe the histopathological changes in the larvae.

METHODSThe number of dead larvae was recorded after application of K-01 at different concentrations under different illumination conditions. The content variation of the midgut, malpighian tubules and fat bodies in the larvae was observed microscopically, and the genomic DNA of the larvae was extracted for electrophoresis to identify the target bands.

RESULTSThe maximum larvae-killing effect was achieved with 50 mg/ml K-01 applied under sunlight (100% killing 24 hours after application). Optical microscopic observation of the killed larvae revealed severe damage of the mid-intestinal cells that showed disintegration and elongation. Distinct vacuoles were observed in the fat body cells, in which red droplets were seen to assemble around the cell nuclei. The result of 0.8% agarose gel electrophoresis of the larvae genomic DNA presented typical ladder patterns, suggesting the presence of cell apoptosis.

CONCLUSIONK-01 is an effective photoactivated insecticide.

Aedes ; drug effects ; growth & development ; radiation effects ; Animals ; Insecticides ; toxicity ; Larva ; drug effects ; growth & development ; radiation effects ; Ultraviolet Rays

OBJECTIVEThis study aims to reveal the effect of total ginsenoside on the protein content and digestive enzyme activities of 4th-instar Mythimna separata larvae, including alpha-amylase and cellulose, and explore the ecological function of total ginsenoside.

METHODWhile simulating natural growing condition indoors, 4th-instar M. separata larvae were fed by poison leaf disk method. The protein content was tested by Lowry Protein Assay Kit method, the activity of alpha-amylase was measured by dinitrosalicylic acid test, and the activity of cellulase was determined by the filter paper method.

RESULTThe total ginsenoside could reduce the content of protein of 4th-instar M. separata larvae significantly, and the activity of digestive enzyme, including alpha-amylase and cellulase. The protein content, alpha-amylase and cellulase activity of treatments were obviously lower than that of the control. Inhibition ratio of alpha-amylase and cellulase activity was positively correlated with total ginsenoside concentration: i. e. 20 g x L(-1) > 10 g x L(-1) > 5 g x L(-1).

CONCLUSIONThe results suggest that the inhibition effect of total ginsenoside on protein content and digestive enzymes may be one of the causes to antifeedant and dysplasia of M. separata larvae.

Animals ; Digestion ; Ginsenosides ; pharmacology ; Insect Proteins ; metabolism ; Larva ; drug effects ; enzymology ; growth & development ; Moths ; drug effects ; enzymology ; growth & development

To evaluate the effects of pesticides to parasite eggs, Ascaris suum eggs were incubated with 5 different pesticides (1:1,500-1:2,000 dilutions of 2% emamectin benzoate, 5% spinetoram, 5% indoxacarb, 1% deltamethrin, and 5% flufenoxuron; all v/v) at 20degrees C for 6 weeks, and microscopically evaluated the egg survival and development on a weekly basis. The survival rate of A. suum eggs incubated in normal saline (control eggs) was 90+/-3% at 6 weeks. However, the survival rates of eggs treated with pesticides were 75-85% at this time, thus significantly lower than the control value. Larval development in control eggs commenced at 3 weeks, and 73+/-3% of eggs had internal larvae at 6 weeks. Larvae were evident in pesticide-treated eggs at 3-4 weeks, and the proportions of eggs carrying larvae at 6 weeks (36+/-3%-54+/-3%) were significantly lower than that of the control group. Thus, pesticides tested at levels similar to those used in agricultural practices exhibited low-level ovicidal activity and delayed embryogenesis of A. suum eggs, although some differences were evident among the tested pesticides.
Animals ; Ascaris suum/*drug effects/growth & development ; Female ; Larva/drug effects/growth & development ; Microscopy ; Pesticides/*pharmacology ; Survival Analysis ; Temperature ; Time ; Zygote/*drug effects/growth & development

OBJECTIVETo evaluate the antifeedant, insecticidal and growth inhibition activities of Solanum pseudocapsicum (S. pseudocapsicum) seed extracts against Spodoptera litura (S. litura) and Helicoverpa armigera (H. armigera).

METHODSHexane, diethyl ether, dichloromethane and ethyl acetate seed extracts were prepared and tested for antifeedant, insecticidal and growth inhibitory activities against fourth instar larvae of S. litura and H. armigera.

RESULTSEthyl acetate extract showed promising antifeedant and insecticidal activities against S. litura and H. armigera. Percentage of deformed larvae, pupae and adults were maximum in treatment of ethyl acetate extract. Percentage of successful adult emergence was deteriorated by seeds on extract treated larvae.

CONCLUSIONSEthyl acetate extracts of S. pseudocapsicum, showed higher efficiency of antifeedant, insecticidal and growth inhibition activities. Hence, it can be used to controll agricultural insect pests, S. litura and H. armigera.

Animals ; Humans ; Insecticides ; pharmacology ; Larva ; drug effects ; growth & development ; Lethal Dose 50 ; Moths ; drug effects ; growth & development ; Pest Control ; Plant Extracts ; pharmacology ; Solanaceae ; chemistry ; Spodoptera ; drug effects ; growth & development

OBJECTIVETo study the anti-feeding effect of total ginsenoside of ginseng stems and leaves on Heliothis dipsacea larvae.

METHODThe natural growing condition for lavae was simulated indoors. The anti-feeding effect of total ginsenoside on Heliothis dipsacea larvae was studied by leaf disc test.

RESULTThe total ginsenoside appeared showed a significant antifeeding effect. The Heliothis dipsacea larvae fed with the leaves of soybean treated with 2.0%, 1.0% and 0.5% total ginsenoside, respectively. At 8 h, non-selective anti-feeding rate were 93.40%, 83.42% and 75.19%, and selective anti-feeding rate were 77.53% , 73.58% and 58.86%.

CONCLUSIONThe toatal ginsenoside had significant inhibition effect on Heliothis dipsacea larvae, and inhibition effect increases as the increase of concentration ginsenoside.

Animals ; Feeding Behavior ; drug effects ; Ginsenosides ; pharmacology ; Larva ; drug effects ; growth & development ; physiology ; Moths ; drug effects ; growth & development ; physiology ; Panax ; chemistry ; Plant Extracts ; pharmacology ; Plant Leaves ; chemistry ; Plant Stems ; chemistry

ENHANCIN is an enhancing protein chiefly found in insect baculoviruses. One ENHANCIN homologue was identified, by blast method, in Agrotis Segetum granulovirus (AgseGV) genome, named enhancin-like. Sequence analysis indicated that this gene includes the conserved domains, conserved in other ENHANCIN, and it has no signal peptide or a-transmembrane helix. A proline-rich domain, which is similar to those of mammals, is present at its C-terminal. To analyze the synergistic function of AgseGV enhancin-like gene, prokaryotic expression vectors of its whole gene and the 5'-truncated fragment (1, 017bp) were constructed. Expression product of truncated fragment was purified by chromatography, and then it was used to prepare antibody. The expression product of whole gene was identified by Western blot with specific antibody and anti-His-Tag antibody. Bioassay proved that the expression product of whole gene can increase the mortality with 16.25% to 3th instar larvae of Helicoverpa armigera (HaNPV: 1.17 x 10(2) PIBS/mL), while the truncated fragment has no obvious synergistic function.
Amino Acid Sequence ; Animals ; Baculoviridae ; genetics ; metabolism ; Gene Expression ; Insect Control ; Larva ; drug effects ; growth & development ; Molecular Sequence Data ; Moths ; drug effects ; growth & development ; Pest Control, Biological ; Viral Proteins ; genetics ; isolation & purification ; metabolism ; toxicity

OBJECTIVETo assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant, Mentha piperita (M. piperita) against the larval and adult stages of Aedes aegypti (Ae. Aegypti).

METHODSThe larvicidal potential of peppermint oil was evaluated against early fourth instar larvae of Ae. aegypti using WHO protocol. The mortality counts were made after 24 and 48 h, and LC50 and LC90 values were calculated. The efficacy of peppermint oil as mosquito repellent was assessed using the human-bait technique. The measured area of one arm of a human volunteer was applied with the oil and the other arm was applied with ethanol. The mosquito bites on both the arms were recorded for 3 min after every 15 min. The experiment continued for 3 h and the percent protection was calculated.

RESULTSThe essential oil extracted from M. piperita possessed excellent larvicidal efficiency against dengue vector. The bioassays showed an LC50 and LC90 value of 111.9 and 295.18 ppm, respectively after 24 h of exposure. The toxicity of the oil increased 11.8% when the larvae were exposed to the oil for 48 h. The remarkable repellent properties of M. piperita essential oil were established against adults Ae. aegypti. The application of oil resulted in 100% protection till 150 min. After next 30 min, only 1-2 bites were recorded as compared with 8-9 bites on the control arm.

CONCLUSIONSThe peppermint essential oil is proved to be efficient larvicide and repellent against dengue vector. Further studies are needed to identify the possible role of oil as adulticide, oviposition deterrent and ovicidal agent. The isolation of active ingredient from the oil could help in formulating strategies for mosquito control.

Aedes ; drug effects ; growth & development ; Animals ; Insect Repellents ; pharmacology ; Insecticides ; pharmacology ; Larva ; drug effects ; growth & development ; Mentha piperita ; chemistry ; Mosquito Control ; methods ; Oils, Volatile ; pharmacology ; Plant Leaves ; chemistry ; Plant Oils ; pharmacology

Zebrafish was selected as model animal, and glucocorticoid dexamethasone was used as a model compound to establish a rapid and high efficient osteopenia model. Zebrafish larvae at 4 days post fertilization (dpf) were exposed to a serial concentrations of dexamethasone solutions, and 0.5% DMSO was selected as the vehicle control group. All groups were incubated in 24-well plates (28.5 degrees C) until 9 dpf. In addition, effects of 10 micromol x L(-1) dexamethasone on preventing against osteopenia induced by etidronate disodium were also investigated. Zebrafish bones at 9 dpf were stained with alizarin red. Quantitative analysis of the stained area was performed by microscopic inspection and digital imaging methods to reflect the amount of bone mineralization. Results showed that dexamethasone group at 2.5, 10 and 25 micromol x L(-1) can decrease the staining area and the staining optical density values of zebrafish head bones when compared with the vehicle control group (0.5% DMSO), which suggested that dexamethasone can significantly reduce the zebrafish mineralized bone and the bone mineral density. Results also showed that 15 and 30 microg x mL(-1) etidronate disodium can increase the mineralized matrix of zebrafish head bone and prevent against osteopenia induced by dexamethasone. In conclusion, the study indicated that zebrafish can be an idea osteopenia model induced by dexamethasone.
Animals ; Bone Density ; drug effects ; Bone Density Conservation Agents ; pharmacology ; therapeutic use ; Bone Diseases, Metabolic ; chemically induced ; prevention & control ; Calcification, Physiologic ; drug effects ; Dexamethasone ; toxicity ; Disease Models, Animal ; Etidronic Acid ; pharmacology ; therapeutic use ; Larva ; drug effects ; growth & development ; Zebrafish

Although rodents have previously been used in ecotoxicological studies, they are expensive, time-consuming, and are limited by strict legal restrictions. The present study used a zebrafish (Danio rerio) model and generated data that was useful for extrapolating toxicant effects in this system to that of humans. Here we treated embryos of the naive-type as well as a transiently transfected zebrafish liver cell line carrying a plasmid (phAhREEGFP), for comparing toxicity levels with the well-known aryl hydrocarbon receptor (AhR)-binding toxicants: 3,3',4,4',5-pentachlorobiphenyl (PCB126), 2,3,7,8-tetrachlorodibenzo-p-dioxin, and 3-methylcholanthrene. These toxicants induced a concentration-dependent increase in morphological disruption, indicating toxicity at early life-stages. The transient transgenic zebrafish liver cell line was sensitive enough to these toxicants to express the CYP1A1 regulated enhanced green fluorescent protein. The findings of this study demonstrated that the zebrafish in vivo model might allow for extremely rapid and reproducible toxicological profiling of early life-stage embryo development. We have also shown that the transient transgenic zebrafish liver cell line can be used for research on AhR mechanism studies.
Animals ; Benz(a)Anthracenes/toxicity ; Cell Line ; Green Fluorescent Proteins ; Hepatocytes/cytology/physiology ; Larva/drug effects/growth & development ; Lethal Dose 50 ; Polychlorinated Biphenyls/toxicity ; Tetrachlorodibenzodioxin/toxicity ; Water Pollutants, Chemical/*adverse effects ; Zebrafish/*physiology

OBJECTIVETo evaluate the ovicidal and larvicidal activities of aqueous and ethanolic extracts of leaves of Dichrocephala integrifolia (D. integrifolia) against the eggs (fresh and embryonnated), the first and second larval stages of Heligmosomoides bakeri. In order to verify if this medicinal plant possesses active compounds capable of inhibiting the embryonation and hatching of eggs or to induce the mortality of larvae (L1 and L2).

METHODSdried extracts were diluted in distilled FIV water to obtain five different concentrations: 625, 1,250, 2,500, 3,750 and 5,000 µg/mL. Fresh eggs obtained from artificially infected mice feces were exposed to these different concentrations for 48 h. Time of contact for embryonated eggs was 6 h while L1 and L2 larvae were exposed for 24 h. Distilled water (placebo) and 1.5% DMSO were used as negative controls.

RESULTSDistilled water, and 1.5% DMSO had no effect on embryonation, hatching and larval survival. Aqueous extracts of D. integrifolia showed a weak activity against all stages of the parasite at all concentrations tested. On the contrary, the ethanolic extract of D. integrifolia inhibited the embryonation of 87.5% of fresh eggs, the hatching of 81.1% of embryonated eggs and induced the mortality of 98.1% and 98% of L1 and L2 larvae respectively at 5,000 µg/mL.

CONCLUSIONSThe results of the present study indicate that the ethanolic extracts of D. integrifolia contained compounds with ovicidal and larvicidal properties. In spite of these results, in vivo tests, studies on toxicity and mechanism of action of active compounds are also needed to validate the utilisation of this medicinal plant by population of Dschang-Cameroon to treat gastro-intestinal parasites.

Animals ; Antinematodal Agents ; pharmacology ; therapeutic use ; Asteraceae ; chemistry ; Dose-Response Relationship, Drug ; Heligmosomatoidea ; drug effects ; growth & development ; Larva ; drug effects ; Mice ; parasitology ; Ovum ; drug effects ; Plant Extracts ; pharmacology ; therapeutic use ; Plant Leaves ; chemistry ; Rodent Diseases ; drug therapy ; Strongylida Infections ; drug therapy ; veterinary