Insulin-like growth factor (IGF) performance in ovarian function and applications in reproductive biotechnologies.

The role of the insulin-like growth factor (IGF) system has attracted close attention. The activity of IGF binding proteins (IGFBPs) within the ovary has not been fully elucidated to date. These proteins bind to IGF with an equal, or greater, affinity than to the IGF1 receptor, thus being in the main position to regulate IGF signalling, in addition to extending the half-life of IGFs within the bloodstream and promoting IGF storage in specific tissue niches. IGF1 has an important part in cell proliferation, differentiation and apoptosis. Considering the importance of IGFs in oocyte maturation, this review sought to elucidate aspects including: IGF production mechanisms; constituent members of their family and their respective functions; the role that these factors play during folliculogenesis, together with their functions during oocyte maturation and apoptosis, and their performance during luteal development. This review also explores the role of IGFs in biotechnological applications, focusing specifically on animal genetic gain.

Multilevel Toxicity Evaluations of Polyethylene Microplastics in Zebrafish (Danio rerio).

Microplastics in freshwater environments pose a serious threat to living beings. Polyethylene microplastics (PE-MP) are the type most used around the world as microbeads in personal care products, and they have been found in aquatic organisms. The behavior and toxicity of fluorescent PE-MP spheres with an average diameter of 58.9 µm were studied in adult, juvenile and embryo zebrafish (Danio rerio). The adults were studied for genotoxicity, cytotoxicity, histology and biochemical markers. Juveniles underwent a follow-up in the gastrointestinal (GI) tract with histologic observations, and embryos were studied for embryotoxicity with the FET-test. In adults, micronucleus test and comet assays found neither genotoxicity after acute exposure for 96 h at concentrations of 0.0, 12.5, 50 and 100 mg.L-1, nor cytotoxicity through the nuclear abnormalities test. Acetylcholinesterase (AChE), Glutathione-S-Transferase (GST) and Lactate Dehydrogenase (LDH) activities were measured in adults exposed for 96 h. The AChE and GST activities were significantly changed, while no changes occurred for LDH. In conclusion, these PE-MP spheres did not cause serious toxic effects in zebrafish because there was no internalization. The observed biochemical changes in AChE and GST may be associated with GI microbiological dysbiosis, previously reported. The PE-MP spheres in the intestine of juveniles remained present for 12-15 days on average after the post-exposure clearance study, showing a slow depuration. The histological analysis, in adults, found no internalization of these microbeads, with complete depuration. The PE-MP spheres did not cross the chorion barrier, showing no embryotoxic effects after exposures at 0.0, 6.25, 12.5, 50.0 or 100.0 mg.L-1 for 96 h.

In the screening of alternative insecticides to control Aedes aegytpti larvae 2-methylanthraquinone showed no genotoxicity and low toxicity to zebrafish (Danio rerio).

The threats posed by insecticide resistance to Aedes aegypti in the context of controlling dengue have led to an urgent search for an environmentally safer alternative chemical with more effective larvicidal properties. Among many molecules tested, 2-methylanthraquinone showed the lowest LC50 for A. aegypti in a previous study and the highest LC50 for zebrafish embryos. Embryos were exposed at concentrations of 1.0, 2.19, 4.78, 10.46, 22.87, 50.0 and 100.0 mg/L, and malformations and mortality were significantly observed only at the highest exposures of 50 and 100 mg/L after 96 h. Micronucleus test and comet assay in zebrafish adults were both negative after exposures at 6.25, 12.5, 25.0, 50.0 and 100.0 mg/L for 96 h. Several biochemical biomarkers were analyzed in adults, and 2-methylanthraquinone did not interfere with acetylcholinesterase activity. The lactate dehydrogenase activity was higher at concentrations of 25 and 100 mg/L. Glutathione-S-Transferase (GST) activities were tested in the gill and body (muscle tail). The gill was more sensitive than body for GST activity after exposure to 2-methylanthraquinone, showing the highest activities, and 2-methylanthraquinone showed low toxicity to a non-target organism.