Gradient in cytoplasmic pressure in germline cells controls overlying epithelial cell morphogenesis.

It is unknown how growth in one tissue impacts morphogenesis in a neighboring tissue. To address this, we used the Drosophila ovarian follicle, in which a cluster of 15 nurse cells and a posteriorly located oocyte are surrounded by a layer of epithelial cells. It is known that as the nurse cells grow, the overlying epithelial cells flatten in a wave that begins in the anterior. Here, we demonstrate that an anterior to posterior gradient of decreasing cytoplasmic pressure is present across the nurse cells and that this gradient acts through TGFß to control both the triggering and the progression of the wave of epithelial cell flattening. Our data indicate that intrinsic nurse cell growth is important to control proper nurse cell pressure. Finally, we reveal that nurse cell pressure and subsequent TGFß activity in the stretched cells combine to increase follicle elongation in the anterior, which is crucial for allowing nurse cell growth and pressure control. More generally, our results reveal that during development, inner cytoplasmic pressure in individual cells has an important role in shaping their neighbors.

Variations in basement membrane mechanics are linked to epithelial morphogenesis.

The regulation of morphogenesis by the basement membrane (BM) may rely on changes in its mechanical properties. To test this, we developed an atomic force microscopy-based method to measure BM mechanical stiffness during two key processes in Drosophila ovarian follicle development. First, follicle elongation depends on epithelial cells that collectively migrate, secreting BM fibrils perpendicularly to the anteroposterior axis. Our data show that BM stiffness increases during this migration and that fibril incorporation enhances BM stiffness. In addition, stiffness heterogeneity, due to oriented fibrils, is important for egg elongation. Second, epithelial cells change their shape from cuboidal to either squamous or columnar. We prove that BM softens around the squamous cells and that this softening depends on the TGFß pathway. We also demonstrate that interactions between BM constituents are necessary for cell flattening. Altogether, these results show that BM mechanical properties are modified during development and that, in turn, such mechanical modifications influence both cell and tissue shapes.

Consumers' Perceptions about Edible Insects' Nutritional Value and Health Effects: Study Involving 14 Countries.

Insects have been consumed for time immemorial in many regions of the globe. However, in other parts, they are not traditionally eaten. Because they are a more sustainable source of animal protein and provide valuable nutrients as well as bioactive compounds with beneficial effects on the human body, their consumption is encouraged. Knowledge can serve as a tool for better acceptance of insects as food. In this context, the present work investigated the knowledge about the nutritional value and health effects of edible insects in different countries. Data were collected by employing a questionnaire survey translated into the different languages of all participating countries and were treated using statistical tools. A total of 7222 responses were obtained. The results indicated that for many issues, the participants manifested a neutral opinion (neither agree nor disagree), but the participants who manifested agreement/disagreement were generally well informed. They were also able to identify untrue facts and answer accordingly by disagreeing. Factor analysis showed four groups of questions: nutritive value, negative perception and risks, safety and benefits of insects and contamination and harmful components. Finally, significant differences were observed according to the sociodemographic variables studies (sex, age, education, living environment and country), with age and country being the most influential of the sociodemographic factors on knowledge. Therefore, increasing knowledge is envisaged as an essential factor in augmenting the recognition of edible insects as a nutritional food, presenting health benefits apart from being a more sustainable source of animal protein when compared with beef or pork meats.

Survival of heat stress with and without heat hardening in Drosophila melanogaster: interactions with larval density.

Survival of a potentially lethal high temperature stress is a genetically variable thermal adaptation trait in many organisms. Organisms cope with heat stress by basal or induced thermoresistance. Here, we tested quantitative trait loci (QTL) for heat stress survival (HSS) in Drosophila melanogaster, with and without a cyclic heat-hardening pre-treatment, for flies that were reared at low (LD) or high (HD) density. Mapping populations were two panels of recombinant inbred lines (RIL), which were previously constructed from heat stress-selected stocks: RIL-D48 and RIL-SH2, derived from backcrosses to stocks of low and high heat resistance, respectively. HSS increased with heat hardening in both LD and HD flies. In addition, HSS increased consistently with density in non-hardened flies. There was a significant interaction between heat hardening and density effects in RIL-D48. Several QTL were significant for both density and hardening treatments. Many QTL overlapped with thermotolerance QTL identified for other traits in previous studies based on LD cultures only. However, three new QTL were found in HD only (cytological ranges: 12E-16F6; 30A3-34C2; 49C-50C). Previously found thermotolerance QTL were also significant for flies from HD cultures.