Exposure to sub-lethal dose of a combination insecticide during early embryogenesis influences the normal patterning of mesoderm resulting in incomplete closure of ventral body wall of chicks of domestic hen

Embryonic Flubendiamide Exposure Alters Expression of OTX2 and Other Early Regulators in Domestic Chick Leading to Congenital Eye Defects

Flubendiamide, a phthalic acid diamide insecticide, has been implicated in potential teratogenic effects on non-target organisms, especially during embryonic development. This study examines the impact of flubendiamide on eye development in chick embryos, a well-established model for vertebrate development. Exposure to 0.5 µg/µL of flubendiamide significantly impaired early ocular morphogenesis, resulting in severe defects such as underdeveloped optic cups and the absence of lens and corneal structures. Histopathological analysis demonstrated disrupted optic cup differentiation, while in silico docking studies revealed strong interactions between flubendiamide and key oculogenic proteins, including OTX2, PAX6, and SOX2. These interactions were associated with altered expression patterns of these critical regulators, alongside overexpression of SHH and downregulation of BMP4, BMP7, and FGF8, which are essential for optic vesicle formation and lens differentiation. Additionally, increased CASPASE-3 expression indicated enhanced apoptosis, contributing to the observed ocular anomalies. These findings suggest that flubendiamide disrupts key signaling pathways necessary for proper eye development, potentially leading to congenital eye defects. The study highlights the need for a thorough evaluation of the molecular mechanisms driving flubendiamide-induced teratogenicity to ensure safer pesticide use and protect environmental and human health.

Impacts of a glyphosate-based herbicide on the gut microbiome of three earthworm species (Alma millsoni, Eudrilus eugeniae and Libyodrilus violaceus): A pilot study

While the impact of glyphosate-based herbicides (GBHs) on earthworms has been studied, little is known about their effects on the earthworm gut microbiome. This study investigated the impact of a GBH on the gut microbial communities of three earthworm species (Alma millsoni, Eudrilus eugeniae and Libyodrilus violaceus). Earthworm species accommodated in soil were sprayed with 115.49 mL/m² of Roundup® Alphée or water. Gut microbiome composition was analysed using 16S rRNA Bacterial Tag-Encoded FLX Amplicon Pyrosequencing (bTEFAP) at the 8th week post-herbicide application. A profound shift in bacterial populationswas observed in all exposed earthworms with Proteobacteria becoming the dominant phylum. Affected bacteria were mostly from the genus Enterobacter, Pantoea and Pseudomonas, which together represented approximately 80 % of the total abundance assigned at the genus level in exposed earthworms, while they were present at a minor abundance (∼1%) in unexposed earthworms. Although consistent results were observed between the three groups of worm species, it is not possible to generalize these outcomes due to a lack of biological replicates, which does not allow for inferential statistical analysis. Nevertheless, our study is the first to report the effects of a GBH on the earthworm gut microbiome and paves the way for future more comprehensive investigations.

Assessment of acute toxicity and biochemical responses to chlorpyrifos, cypermethrin and their combination exposed earthworm, Eudrilus eugeniae

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In the present study, co-exposed administered pesticides induced a higher level of toxicity to Eudrilus eugeniae.

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Statistically significant changes were observed after 48 h exposure of CPF, cypermethrin and combination of the two, reflects the synergistic cumulative impact on the AChE and oxidative stress parameters in dose- dependent manner.

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Significant changes were observed in different body segments (Pre-Clitellar, Clitellar and Post-Clitellar) of earthworm in tissue specific pattern.

Recurrent application of chemical pesticides in the agricultural fields have adverse impact on flora and fauna of soil ecosystem. Earthworms immensely contribute in increasing the fertility of soil. They may act as a bioindicator for the ecotoxicological analysis of pesticide induced soil pollution. Earthworms, Eudrilus eugeniae were exposed to different concentrations of pesticides chlorpyrifos (OP), cypermethrin (a pyrethroid) and their combination for 48 h by paper contact toxicity method. The LC₅₀ for commercial grade of chlorpyrifos, cypermethrin and combined pesticides were determined as 0.165, 0.066 and 0.020 μg/cm², respectively. To assess the sub-lethal effect of these pesticides, E. eugeniae were exposed to 5% and 10% of LC₅₀ of the pesticides for 48 h. Variation in morpho-behavioural changes such as coiling, clitellar swelling, mucus release, bleeding and body fragmentation in earthworms were observed after exposure of both pesticides and their combination. Various biochemical estimations such as specific activity of acetylcholinesterase (AChE), superoxide dismutase (SOD), catalase (CAT), glutathione -S-transferase (GST); levels of lipid peroxidation (LPO) and reduced glutathione (GSH) were carried out in different body segments. Significant changes in these stress markers were observed at low and high sub-acute concentration of pesticides exposed earthworm, Eudrilus eugeniae. Such changes indicate potential health risk to E. eugeniae if exposed to the high concentrations of these pesticides accumulated in soil.