Critical electrolyte concentration of silk gland chromatin of the sugarcane borer Diatraea saccharalis, induced using agrochemicals

Abstract

ABSTRACT. The sugarcane borer Diatraea saccharalis is widely known as the main pest of sugarcane crop, causing increased damage to the entire fields. Measures to control this pest involve the use of chemicals and biological control with Cotesia flavipes wasps. In this study, we evaluated the insecticides fipronil (Frontline; 0.0025%), malathion (Malatol Bio Carb; 0.4%), cipermetrina (Galgotrin; 10%), and neem oil (Natuneem; 100%) and the herbicide nicosulfuron (Sanson 40 SC; 100%) in the posterior region silk glands of 3rd-and 5th-instar D. saccharalis by studying the variation in the critical electrolyte concentration (CEC). Observations of 3rd-instar larvae indicated that malathion, cipermetrina, and neem oil induced increased chromatin condensation that may consequently disable genes. Tests with fipronil showed no alteration in chromatin condensation. With the use of nicosulfuron, there was chromatin and probable gene decompaction. In the 5th-instar larvae, the larval CEC values indicated that malathion and neem oil induced increased chromatin condensation. The CEC values for 5th-instar larvae using cipermetrina, fipronil, and nicosulfuron Agrochemical-induced CEC in sugarcane borer indicated chromatin unpacking. These observations led us to conclude that the quantity of the pesticide does not affect the mortality of these pests, can change the conformation of complexes of DNA, RNA, and protein from the posterior region of silk gland cells of D. saccharalis, activating or repressing the expression of genes related to the defense mechanism of the insect and contributing to the selection and survival of resistant individuals.

Toxicity and effects of the neonicotinoid thiamethoxam on Scaptotrigona bipunctata lepeletier, 1836 (Hymenoptera: Apidae)

“…Santos et al conducted CEC tests with salivary glands of third and fifth instars larvae of Diatraea saccharalis submitted to oral contamination with the insecticides (fipronil, malathion, cypermethrin, and neem oil). In this study, several changes were detected in the chromatin structure.…”

“…In addition to the isoenzymes analyzes, changes in chromatin integrity are an important tool to identify the presence of external agents . Therefore, nuclear basophilia has been studied in order to analyze the levels of DNA‐protein complexation in the chromatin, based on the use of the cationic dye Toluidine Blue (TB) .…”

Effects of combined fungicide in stingless bees Scaptotrigona bipunctata

“…Changes in chromatin integrity are a useful tool to identify the presence of external agents in the body (Santos et al, 2014). Thus, nuclear basophilia can be established and used to estimate the levels of DNA-protein complexation in the chromatin, using the cationic dye Toluidine Blue (TB) (Vidal, 1987).…”

“…It is essential to measure the effectiveness of agrochemicals used in crops on target and non-target insects, such as bees. Changes in chromatin integrity can be used to identify the presence of external agents (Santos et al, 2014).…”

Comparative toxicity of fipronil, malathion, and thiamethoxam on the stingless bee Tetragonisca fiebrigi (Schwarz, 1938)

“…Chromatin modification can also be used to identify the effects of external factors (Catae, Roat, Oliveira, Nocelli, & Malaspina, 2014;Santos et al, 2014;Moreira et al, 2018). This is achieved by analyzing the critical electrolyte concentration (CEC), using a technique developed by Vidal and Mello (1989).…”