Giving bodies to ghosts: locating molecules in the very place where they exert their biological roles.

This paper reviews some of the goals of our investigations published over the years on Rivista di Istochimica Normale e Patologica, Basic and Applied Histochemistry, and the European Journal of Histochemistry - EJH. In a series of papers, we published some of the basic cytochemical features of the sperm cytodifferentiation process for the first time. This was a conceptual and practical prerequisite to the in situ quantitative evaluation of sperm DNA content. We showed that the discrepancy between the expected 1:2 ratio when comparing sperm versus somatic cell DNA content (sperm DNA content is always far low from the theoretical value) is due to DNA losses caused by the hydrochloric treatment entailed by the Feulgen reaction. The knowledge of the specific losses that occur during the various steps of the Feulgen reaction has allowed us to use it critically in Genome Size studies to highlight: - sperm aneuploidy in chromosomally derived subfertility; - the broad variability range of Mammalian genome sizes; - that termites are roaches (after decades of discussion on this topic). In addition, in a seminal paper on human oocytes, we showed (by transmission electron microscopy) a specific chromatin and cytoplasmic organization (both essential for further embryo development) linked to oocyte maturation arrest, a datum quite relevant to treating unmet therapeutic needs in human and veterinary reproduction.