Effect of styrene oxide and diethyl maleate on expression of cytochrome P450 family 1 and glutathione store in mouse liver

Purpose: To determine the effect of the glutathione (GSH) suppressors styrene oxide (SO) and diethyl maleate (DEM) on the hepatic expression of cytochrome P450 family 1 (Cyp1) isoforms that are related to carcinogenesis including Cyp1a1, Cyp1a2, and Cyp1b1. Methods: Seven-week-old ICR mice were intraperitoneally injected with SO (150 and 300 mg/kg/day), DEM (175 and 350 mg/kg/day), or N-acetylcysteine (NAC; 300 and 600 mg/kg/day) for 7, 14, or 28 days. Plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, hepatic Cyp1 expression, total glutathione, reduced glutathione (GSH), and oxidized glutathione (GSSG) were determined. Results: ALT and AST levels were markedly increased by SO and DEM while GSH/GSSG ratio was decreased by SO in all treatments (p < 0.05), while high dose (350 mg/kg/day) DEM significantly suppressed GSH/GSSG ratio at 28 days (p < 0.05). The expressions of Cyp1a1, Cyp1a2, and Cyp1b1 were induced by SO and DEM, corresponding with induction of ethoxy/methoxy-resorufin O- dealkylase activities. Conclusion: The Cyp1 family metabolizes procarcinogens to carcinogenic DNA adducts; exposure to the industrial solvents, SO and DEM, raises the risk of carcinogenesis via GSH depletion coupled with Cyp1 induction.

Function Analysis of P450 and GST Genes to Imidacloprid in Aphis craccivora (Koch)

Aphis craccivora (Koch) is an economically important pest that affects legumes in worldwide. Chemical control is still the primary efficient method for A. craccivora management. However, the mechanism underlying insecticide resistance in A. craccivora has not been elucidated. A previous study observed that piperonyl butoxide (PBO) and diethyl maleate (DEM) significantly synergized imidacloprid in A. craccivora field populations, indicating that cytochrome P450 (P450) and glutathione S-transferase (GST) genes may play pivotal roles in imidacloprid resistance. In this study, 38 P450 genes and 10 GST genes were identified in A. craccivora through transcriptomic analysis. The expression levels of these P450 and GST genes were measured in susceptible (SUS) strains of A. craccivora under imidacloprid treatment with LC15, LC50, and LC85 doses. The expression levels of CYP18A1, CYP6CY21, CYP6DA1, CYP6DA2, CYP4CJ1, CYP4CJ2, and CYP380C6 were up-regulated in the three treatments. Most of these genes belong to CYP3 and CYP4 Clans. In addition, the expression levels of all P450 and GST genes in A. craccivora were also measured in the Juye (JY) and Linqing (LQ) field populations. The expression levels of CYP6DA2, CYP4CJ1, and CYP380C6 were up-regulated in the SUS strain after imidacloprid treatment at three doses, and these genes were overexpressed in the JY population. Furthermore, the sensitivity of A. craccivora to imidacloprid was significantly increased after knockdown of CYP380C6 and CYP6DA2 through RNA interference. These results may help to elucidate the mechanisms underlying of imidacloprid resistance in A. craccivora.

One-pot producing diethyl maleate via catalytic conversion of raw lignocellulosic biomass

Conversion of lignocellulose into a value-added chemical with high selectivity is of great significance but a big challenge due to the structural diversities of biomass components. Here, we reported an...

Assessment of Resistance to Organophosphates and Pyrethroids in Aedes aegypti (Diptera: Culicidae): Do Synergists Affect Mortality?

Aedes aegypti (L.) is the primary vector of Zika, dengue, yellow fever, and chikungunya viruses. Insecticides used in mosquito control can help prevent the spread of vector-borne diseases. However, it is essential to determine insecticide resistance (IR) status before control measures are undertaken. Only the most effective insecticides should be used to avoid ineffective control and/or promotion of IR. Pyrethroids and organophosphates are the most commonly used insecticides for mosquito control. Here, the efficacy of two active ingredients (AIs; permethrin [pyrethroid], chlorpyrifos [organophosphate]), two formulated products (FPs; Biomist [AI: permethrin]) and (Mosquitomist [AI: chlorpyrifos]), and three synergists (piperonyl butoxide, diethyl maleate, S-S-S-tributyl phosphorotrithioate) was evaluated in two Ae. aegypti colonies (pyrethroid resistant and susceptible). Mosquitomist was most effective against the pyrethroid-resistant colony (100% mortality at diagnostic time). Pre-exposure to synergists did not increase the efficacy of AIs against the pyrethroid-resistant colony. Further research is needed to discover how synergists may affect the efficacy of insecticides when used on pyrethroid-resistant mosquitoes.

RESISTANCE MECHANISMS TO ACETAMIPRID IN GERMAN COCKROACH BLATTELLA GERMANICA (L.) (BLATTODEA: ECTOBIIDAE)

The spectrum of resistance to various groups of insecticides of several laboratory strains of German cockroach, Blattella germanica, from different geographically remote regions of Russia is presented. Studies have been carried out on the synergistic effects of desynchronized use of piperonyl butoxide (PBO), S, S, Stributylphosphorotrithioate (DEF), diethyl maleate (DEM) and verapamil (Ver) in combination with 5-7 concentrations of acetamiprid to determine possible resistance mechanisms. The studies were performed on three strains (M1, Moscow; OBN, Obninsk; U1, Yekaterinburg) in comparison with the standard laboratory susceptible strain S-NIID. Acetamiprid resistance was reduced using PBO, DEF, and Ver which indicates the involvement of P450 monooxygenases, esterases, and ABC transporters in this phenomenon. DEM turned out to be less effective. Insecticide multi-resistance is widespread in German cockroaches in Russia.

Synthesis of Unsaturated Esters by Cross-Metathesis of Terpenes and Natural Rubber Using Ru-Alkylidene Catalysts

This study reports the cross-metathesis of bicyclic &#946;-pinene, acyclic cis-3- methylpent-2-ene terpenes and the natural rubber with functionalized olefins, a route for the functionalization of the carbon-carbon double bond of natural products to obtain aliphatic unsaturated esters. The production of unsaturated esters from &#946;-pinene and cis-3- methylpent-2-ene via cross-metathesis reaction with dimethyl maleate and diethyl maleate in the presence of the ruthenium-alkylidene [Ru(Cl)2(=CHPh)(1,3-bis(2,4,6- trimethylphenyl)-2-imidazolidinylidene)(PCy3)] (I), [Ru(Cl)2(=CH(o-isopropoxyphenylmethylene))( 1,3-bis(2,4,6-trimethylphenyl) -2-imidazolidinylidene)] (II) and rutheniumvinylidene [RuCl2(=C=CH(p-C6H4CF3))(PCy3)2] (III) was carried out. Results showed that the reaction of &#946;-pinene with diethyl maleate using II catalyst produced unsaturated esters with 43 % selectivity. I and III catalysts showed low activity toward the cross-metathesis of &#946;-pinene and dimethyl maleate. A survey about the cross-metathesis of acyclic cis-3-methylpent-2-ene with diethyl maleate by II catalyst was also studied. The formation of ethyl but-2-enoate and ethyl-3-methylpent-2-enoate products was highly selective by 63 %. The unsaturated esters formation from the cross-metathesis degradation of natural rubber (99.9 % cis-polyisoprene) with dimethyl maleate and diethyl maleate using I-III catalysts was accomplished as well. I and II catalysts showed high activity in the degradation of natural rubber with diethyl maleate to produce the low molecular weight of oligomers unsaturated ester products (Mn = 1 x 103 g mol-1) with isoprene units of m = 10 – 27 and yields ranging from 68 to 94 %.