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Synthetic Pyrethroid Insecticide (synthetic + pyrethroid_insecticide)
Selected AbstractsClutch morphology and the timing of exposure impact the susceptibility of aquatic insect eggs to esfenvalerateENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2008Katherine R. Palmquist Abstract We investigated Baetis spp. (mayfly), Hesperoperla pacifica (stonefly), and Brachycentrus americanus (caddisfly) susceptibility at the egg stage to esfenvalerate, a synthetic pyrethroid insecticide. Eggs were obtained from the field or from field-collected gravid females at sites near Corvallis (OR, USA) and the Metolius River at Camp Sherman (OR, USA) for static exposures under controlled conditions for temperature and light. Eggs were exposed to esfenvalerate for 48 h at concentrations ranging from 0.025 to 4.0 ,g/L. No effect on mortality or posthatch growth was detected in H. pacifica eggs exposed to esfenvalerate concentrations up to 1.0 ,g/L. Exposure to 0.07 ,g/L of esfenvalerate, however, caused a significant increase in Baetis spp. egg mortality, and exposure of near-eclosion eggs to lower concentrations (0.025 and 0.05 ,g/L) resulted in behavioral effects and reduced survivorship in newly hatched Baetis nymphs. Early stage B. americanus eggs were 10-fold more sensitive to esfenvalerate when removed from the gelatinous clutch before exposure, an indication that the gelatin affords protection from toxicant exposure. Exposures of near-hatch B. americanus clutches to esfenvalerate concentrations ranging between 0.035 and 0.2 ,g/L, however, resulted in significant clutch death within clutches resulting from behavioral aberrations of first-instar larvae. The results of the present study suggest that aquatic insect egg clutch morphology can be a strong influence on susceptibility of embryos to esfenvalerate exposure. [source] Evaluation of cytogenetic effects of lambda-cyhalothrin on human lymphocytesJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 5 2005Rambabu Naravaneni Abstract The genotoxic and cytotoxic potential of lambda-cyhalothrin (LCT), a synthetic pyrethroid insecticide, was investigated on human lymphocytes cultured in vitro. Utilizing the trypan blue dye exclusion technique assay, the LC50 of LCT was found to be 28 , M. Based on the LC50 value, it is seen that LCT was highly toxic to lymphocyte cultures, among other pyrethroid group of pesticides. Chromosomal aberrations induced by LCT were determined using metaphase plate-spreads of lymphocytes. The chromosomal analysis was recorded using Medi-Image software technology. The analysis revealed that more satellite associations and gaps were found, which were statistically significant (p < 0.05) when compared to controls. Comet assay was used to assess the possibility of LCT to induce the damage in DNA, where the increase in comet tail length relates to the extent of DNA single strand breaks. The results presented here indicate that in vitro assays could be used as indicators of cytotoxicity and genotoxicity of the pesticide. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 19:304,310, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20095 [source] Inheritance of beta-cypermethrin resistance in the housefly Musca domestica (Diptera: Muscidae)PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 2 2008Lan Zhang Abstract BACKGROUND: Beta-cypermethrin, a synthetic pyrethroid insecticide, was applied frequently in the control of health pests including houseflies, Musca domestica L., in China. However, different levels of resistance to beta-cypermethrin were monitored in field strains of houseflies. A strain of M. domestica, 4420-fold resistant to beta-cypermethrin after continuous 25 generations of selection, was used in this paper to determine the mode of inheritance of pyrethroid resistance. RESULTS: The estimated realized heritability (h2) of beta-cypermethrin resistance was 0.30 in this resistant strain. Results of bioassays showed no significant difference in values of LD50 and slope of log dose-probit lines between reciprocal progenies F1 and F,1, and yielded values of , 0.10 (F1) and , 0.11 (F,1) for the degree of dominance (D). Chi-square analysis from responses of self-bred and backcross progenies (F2, BC1 and BC2 respectively) indicated that the null hypothesis, a single gene responsible for resistance, was accepted. The minimum number of independent segregation genes was 0.93 for F1 by Lande's method. CONCLUSION: It was concluded that beta-cypermethrin resistance in the housefly was inherited as a single, major, autosomal and incompletely recessive factor. These results would provide the basic information for pest management programmes. Copyright © 2007 Society of Chemical Industry [source] An in vitro study on reproductive toxicology of Deltamethrin on rat spermatozoaANDROLOGIA, Issue 4 2010F. Ben Abdallah Summary Recent findings indicate that synthetic pyrethroid insecticide may induce toxic manifestations by enhancing the production of reactive oxygen species and disrupting the balance between pro-oxidants and antioxidants as a result of lipid peroxidation (LP) of cell membranes. The aim of the study was to examine the potency of Deltamethrin (Del) to induce oxidative stress response in rat spermatozoa in vitro. Spermatozoa were incubated with different concentrations (0, 10, 50, 100 and 200 ,m) of Del for 3 h at 37 °C. After that, sperm parameters (motility, viability and abnormal morphology), malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) levels were determined. We found that in vitro exposure to Del caused a significant decline of sperm motility and viability and increase of abnormal sperm morphology, MDA, SOD and CAT levels at different concentrations of Del. This study demonstrated that Del caused deterioration in sperm motility and viability, and induction in LP, abnormal morphology of spermatozoa and antioxidants enzyme activities. [source] Susceptibility of four field populations of the diamondback moth Plutella xylostella L. (Lepidoptera: Yponomeutidae) to six insecticides in the Sydney region, New South Wales, AustraliaAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 4 2008Vincent Y Eziah Abstract Concerns about the failure of insecticides to control the diamondback moth (DBM) Plutella xylostella in the Sydney region of New South Wales, Australia, necessitated the current investigation to establish the susceptibility of four field populations of the DBM to six insecticides. These include two each of organophosphates (OPs), and synthetic pyrethroid insecticides as well as two new products with different modes of action, spinosad and indoxacarb, currently recommended for DBM control in the region. Topical application of the insecticides to the third-instar larvae showed high resistance to pyrethroids (permethrin and esfenvalerate) of 35.0- to 490.0-fold. Resistance to the OPs (methamidophos and chlorpyrifos) and indoxacarb ranged from 12.1- to 36.2-fold and from 11.4- to 34.6-fold, respectively. However, the field populations were susceptible to spinosad (resistance factors only two- to threefold compared with the susceptible strain). A 2 h pre-treatment of the esfenvalerate-resistant strain with the synergists piperonyl butoxide and diethyl maleate increased the toxicity of esfenvalerate by 30.0- and 1.9-fold, respectively, suggesting the involvement of esterases and/or monooxygenases as the key mechanism(s) of insecticide resistance with glutathione S-transferases playing a minor role. [source] | |||||||||||||