The spatio-temporal regulation of gene expression determines the fate and function of various cells and tissues and, as a consequence, the correct development and functioning of complex organisms. Certain mechanisms of gene activity regulation provide adequate cell responses to changes in environmental factors. Aside from gene expression disorders that lead to various pathologies, alterations of expression of particular genes were shown to significantly decrease or increase the lifespan in a wide range of organisms from yeast to human. Drosophila fruit fly is an ideal model system to explore mechanisms of longevity and aging due to low cost, easy handling and maintenance, large number of progeny per adult, short life cycle and lifespan, relatively low number of paralogous genes, high evolutionary conservation of epigenetic mechanisms and signalling pathways, and availability of a wide range of tools to modulate gene expression in vivo. Here, we focus on the organization of the evolutionarily conserved signaling pathways whose components significantly influence the aging process and on the interconnections of these pathways with gene expression regulation.

The effect of grinding at ambient temperature and at 77 K (CryoMill Retsch) on the polymorphic transitions in α- and ε- chlorpropamide has been compared. The result of grinding of α-chlorpropamide at room temperature could not be interpreted as a mere formation of traces of the ε-polymorph. The diffraction patterns suggested the presence of small amounts of some unknown polymorph, possibly in a mixture with other polymorph(s). Possibly, mechanical treatment gave a defect nanostructured phase with alternating domains. Cryogrinding of α-chlorpropamide did not result in polymorphic transitions. In contrast, cryogrinding of the ε-polymorph was much more efficient than grinding at ambient temperature: almost no changes could be observed at ambient temperature, whereas cryogrinding gave the α-form. The observed phenomena could be interpreted taking into account that at low temperatures the ε-polymorph undergoes a polymorphic transition into another polymorph— the ε′-form. Without grinding, the ε′-form transforms back to the ε-polymorph when heated back to ambient temperature. If grinding takes place in the temperature range of the ε- to ε′-polymorphic transition, the transformation to the α-form occurs. One phase transition, induced by low temperature, facilitates another one, induced by mechanical treatment. The reason for this interesting phenomenon is to be sought in the similarity of the crystal packing of molecules with different molecular conformations in the ε- and ε′-forms, and of the similarity of the molecular conformations despite different crystal packing in the ε′- and α-forms.

Modern views of the development and structural organization of the female reproductive system in Drosophila melanogasterare reviewed. Special emphasis is placed on the generation and development of...