muramidase and imidacloprid

The aim of this study was to assess acute health effects on planters caused by planting conifer seedlings treated with two insecticides, with active ingredients imidacloprid and cypermethrin, in comparison with untreated seedlings.. The investigation was a double-blind crossover study, which included a follow-up of 19 planters over a 3-week period. During Week 1, the 19 planters handled untreated conifer seedlings while they planted imidacloprid- and cypermethrin-treated seedlings during study Week 2 and 3, respectively. Signs and symptoms of acute health effects were documented by a questionnaire, administered by the field staff, during these 3 weeks. Inflammation markers in the nasal mucous membrane were also measured as an objective test. Exposure to cypermethrin was further assessed by measuring 3-phenoxybenzoic acid (3-PBA) in urine. No validated biomarker was available to assess internal exposure to imidacloprid.. No clear, acute adverse health effects could be found in planters during the week of exposure to conifer seedlings treated with imidacloprid (Merit Forest) or cypermethrin (Forester), as compared to during the week of planting untreated seedlings. During the week of cypermethrin exposure, the individuals had 3-PBA values that were 12-54% higher (P < 0.05), depending on the worker, than those observed during the untreated week. There were no statistically significant correlations between the raised levels of 3-PBA and self-reported health problems. These results have been obtained during planting in late summer/early autumn and with good use of protective clothing.. No clear, acute adverse health effects could be found in planters after exposure to conifer seedlings treated with imidacloprid (Merit Forest) or cypermethrin (Forester), as compared with planting untreated seedlings. The metabolite, 3-PBA, was found in low levels in urine and was increased after exposure to cypermethrin. However, no clear relationships could be found between exposure and reported symptoms or between elevated 3-PBA levels and reported symptoms.

Topics: Adult; Air Pollutants, Occupational; Albuminuria; Animals; Benzoates; Biomarkers; Cross-Over Studies; Double-Blind Method; Environmental Monitoring; Female; Follow-Up Studies; Forestry; Humans; Imidazoles; Inhalation Exposure; Insecticides; Logistic Models; Male; Middle Aged; Muramidase; Neonicotinoids; Nitro Compounds; Occupational Diseases; Occupational Exposure; Protective Clothing; Pyrethrins; Skin Absorption; Tracheophyta

Since the introduction of imidacloprid in the early 1990s, it has become one of the most widely applied insecticides, and currently represents about 20% of the global pesticide market (Tomizawa, M.; Casida, J. E. J. Agric. Food Chem 2011, 59, 2883-2886). In the context of this study, our major aim was to comprehensively scrutinize the nature of imidacloprid with two typical model proteins, lysozyme and albumin, by means of circular dichroism (CD), steady-state and time-resolved fluorescence, and molecular modeling at the molecular level. Far-UV CD verified that the spatial structure of both proteins was altered with a distinct reduction of α helix in the presence of imidacloprid suggesting unfolding of the protein (i.e., protein damage). The data of steady-state and time-resolved fluorescence showed that the conjugation of imidacloprid with lysozyme yielded quenching by a static mechanism (KSV = 3.841 × 10(4) M(-1)), while combined static and dynamic properties existed for albumin tryptophan (Trp)-214 fluorescence. Molecular modeling simulations displayed that the imidacloprid binding site was near to the Trp-62 and Trp-63 residues of lysozyme, and it was located at the subdomain IIA (warfarin-azapropazone site) of albumin. Furthermore, the primary forces between protein and imidacloprid are hydrogen bond, hydrophobic, and π-π interactions, but the affinity of lysozyme with imidacloprid is much lower than albumin, probably because the affinity distinctions stem from discrepancy in the three-dimensional structure of the two globular proteins. The results presented here will help to further understand the credible mechanism by which the toxicological implication of neonicotinoid insecticides is palliated by carrier protein.

Topics: Binding Sites; Circular Dichroism; Fluorescence; Hydrogen Bonding; Hydrophobic and Hydrophilic Interactions; Imidazoles; Insecticides; Linear Models; Models, Molecular; Muramidase; Neonicotinoids; Nitro Compounds; Protein Binding; Protein Structure, Secondary; Serum Albumin; Tryptophan