alpha-chymotrypsin and decamethrin

Deltamethrin degradation was assessed by measuring deltamethrin reduction with GC-MS and UV-Vis spectrophotometry following incubation of various concentrations (4.96-24.80 microM) of deltamethrin with alpha-chymotrypsin from bovine pancreas. The retention times of crude products of deltamethrin metabolic reactions were 37.968 min, 37.415 min, 36.490 min, and 35.895 min. The UV-Vis spectrophotometric peak absorbance of deltamethrin was at 264 nm, and the peak absorbance of deltamethrin metabolic products were at 250 nm and 296 nm, respectively. Michaelis-Menten metabolic rate constants (V(max) and K(m)) were calculated by nonlinear regression for chymotrypsin using GraphPad Prism 4.0, the V(max) was 97.97+/-26.57 nmol/L/min and K(m) was 7.84+/-3.83 microM. The larvicidal bioassay tests indicated that the mixture from the degradation reaction showed LC(50) increased significantly (P<0.05). This is the first report demonstrating deltamethrin metabolism by chymotrypsin.

Topics: Animals; Cattle; Chymotrypsin; Gas Chromatography-Mass Spectrometry; Hydrolysis; Insecticides; Larva; Lethal Dose 50; Nitriles; Pyrethrins; Regression Analysis; Spectrophotometry, Ultraviolet

Two serine proteinase genes were isolated from Culex pipiens pallens as significantly up-regulated genes in a deltamethrin-resistant strain through a combination of suppression substractive hybridization and gene expression profiling by macroarrays. These two genes were found to be expressed at least threefold higher in the resistant strain than in the susceptible one. By using rapid amplification of cDNA ends to screen the constructed cDNA library, we cloned these two sequences. There were 909 bp with an open reading frame of 786 bp in the sequence of trypsin cDNA (GenBank/NCBI AF468495), the deduced protein had 261 amino acids, which was most similar to the trypsin gene of Anopheles gambiae. There were 992 bp with an open reading frame of 816 bp in the chymotrypsin cDNA (GenBank/NCBI AY034060), and its deduced amino acid sequence had 271 amino acids, which was most similar to the chymotrypsin-like protein from Aedes aegypti. The two genes were stably expressed in mosquito C6/36 cells, and the expected 29 and 30 kDa bands were shown with Western blot, respectively. In these cells, after deltamethrin treatment, they had protective effects on the viability. The results indicate that trypsin and chymotrypsin were more highly expressed in the deltamethrin-resistant strain, and was related to insecticide resistance in mosquitoes, Cx. pipiens pallens.

Topics: Amino Acid Sequence; Animals; Base Sequence; Chymotrypsin; Culex; Drug Resistance; Gene Expression Regulation; Insecticides; Molecular Sequence Data; Nitriles; Pyrethrins; Serine Endopeptidases; Species Specificity; Trypsin

The effects of pyrethroid pesticides (deltamethrin, permethrin and cypermethrin) and an organophosphate ester (methidation) on the activities of carp trypsin, alpha-chymotrypsin, carboxypeptidase A and lipase were studied. The enzymes were isolated from the gastrointestinal tract and the effects of the pesticides were investigated during incubation for 5 min. The activity of trypsin was influenced only slightly by the presence of deltamethrin and methidation, whereas permethrin and cypermethrin caused significant inhibition. The pyrethroid pesticides at lower concentrations resulted in a slight activation of alpha-chymotrypsin. Methidation inhibited the alpha-chymotrypsin activity by about 20%. These pesticides modified the lipase activity to a lesser extent; the highest inhibition was measured with cypermethrin. The carboxypeptidase A activity was inhibited by both pyrethroid pesticides and methidation. The results suggest that these pesticides might interact with the active conformation of the studied hydrolytic enzymes, resulting in changes in their activities.

Topics: Animals; Carboxypeptidases; Carboxypeptidases A; Carps; Chymotrypsin; Digestion; Industrial Waste; Insecticides; Lipase; Nitriles; Organothiophosphorus Compounds; Permethrin; Pyrethrins; Trypsin; Water Pollution, Chemical

Acute (LD50) and short-term (14 days) toxicological examinations were performed in animal experiments on the interaction of a synthetic pyrethroid Decis 2,5 EC (25 g deltamethrin/l) and of ethylene-bisdithiocarbamate/Dithane M-45 (80% mancozeb), using a 1:5 deltamethrin/mancozeb mixture. LD50 value of the mixture was similar to that of the more toxic Decis. In the short-term examination, some pathologically high AST and ALT values were observed in the treated groups and the deltamethrin content of fatty tissue samples increased parallel with the increase of Decis consumption. The chymotrypsin and lipase activities in the small intestinal mucosa and gamma-GT and LAP activities in the content of the bowels were reduced in several treated groups. The administration of Dithane in a dose in accordance with 20% of the LD50 value (3125 mg/kg b.m.) proved to be more toxic than expected and caused the death of the animals.

Topics: Adipose Tissue; Alanine Transaminase; Animals; Aspartate Aminotransferases; Chymotrypsin; Diet; Drug Interactions; gamma-Glutamyltransferase; Intestinal Mucosa; Lethal Dose 50; Leucyl Aminopeptidase; Lipase; Male; Maneb; Nitriles; Pyrethrins; Rats; Rats, Inbred Strains; Thiocarbamates; Zineb