Thaumetopoea pityocampa is the most important pine defoliator in the Mediterranean basin. Despite being attacked by a number of natural enemies, populations occur frequently at high density in several areas.
Egg parasitism was studied in 27 pine and cedar forests in Algeria, in relation to the host density (tents per tree) and the proportion of forest cover in the landscape.
Egg parasitism varied from 2% to 25%, accounted by two parasitoid species, the specialist Baryscapus servadeii and the generalist Ooencyrtus pityocampae.
Tent density was negatively correlated with parasitism by B. servadeii but not with that of O. pityocampae. Conversely, parasitism by O. pityocampae increased with the proportion of forest and agricultural cover, but not in the case of B. servadeii.
Maximum summer temperature showed no correlation with parasitism rates. Still, temperature frequently exceeded 40 °C during the period of adult parasitoid activity.
The low performance of the egg parasitoids at the southern edge of the host range could be explained by the reduced fecundity of the host, climate effects, and phenological mismatching between the parasitoids and the egg development. These and other factors potentially involved the need to be further explored with a long-term study of population dynamics.
Proanthocyanidins are phenolic compounds abundant in the diet, commonly found in grapes and derivatives, foods known for their health-promoting benefits. There is previous evidence showing the antidiabetic activity of proanthocyanidins, however, their mechanisms of action have not been fully elucidated. This study evaluated the capacity of grape seed proanthocyanidins extract (GSPE) to modulate oxidative stress, nitric oxide levels, mitochondrial dysfunction, apoptosis, and sirtuin expression in endothelial cells EA.hy926 under high glucose condition. In addition, the possible toxic effects of GSPE was evaluated in a zebrafish embryos model. The results showed that GSPE was able to enhance cell viability and avoid the disturbance in redox metabolism induced by high glucose. Moreover, GSPE was able to avoid mitochondria dysfunction and the increased in p53 and poly-(ADP-ribose) polymerase expression induced by high glucose exposition. These effects were attributed to the increase in expression of sirtuin 3, a protein able to regulate mitochondrial function. GSPE in an effective concentration did not show toxic effects in zebrafish embryos model. Taken together, these data elucidate the key molecular target of GSPE for future pharmacological interventions in diabetic patients.
AbstractThe development of new treatments for malignant melanoma, which has the worst prognosis among skin neoplasms, remains a challenge. The tumor microenvironment aids tumor cells to grow and resist to chemotherapeutic treatment. One way to mimic and study the tumor microenvironment is by using three-dimensional (3D) co-culture models (spheroids). In this study, a melanoma heterospheroid model composed of cancer cells, fibroblasts, and macrophages was produced by liquid-overlay technique using the agarose gel. The size, growth, viability, morphology, cancer stem-like cells population and inflammatory profile of tumor heterospheroids and monospheroids were analyzed to evaluate the influence of stromal cells on these parameters. Furthermore, dacarbazine cytotoxicity was evaluated using spheroids and two-dimensional (2D) melanoma model. After finishing the experiments, it was observed the M2 macrophages induced an anti-inflammatory microenvironment in heterospheroids; fibroblasts cells support the formation of the extracellular matrix, and a higher percentage of melanoma CD271 was observed in this model. Additionally, melanoma spheroids responded differently to the dacarbazine than the 2D melanoma culture as a result of their cellular heterogeneity and 3D structure. The 3D model was shown to be a fast and reliable tool for drug screening, which can mimic the in vivo tumor microenvironment regarding interactions and complexity.Graphic abstract相似文献
