Structure analysis of Eledone cirrhosa by CLSM and SFM

CLSM (Confocal Laser Scanning Microscopy) and SFM (Scanning Force Microscopy) can be considered in use as high-powered biophysical tools for investigating the very delicate and complex way in which structure and function are related in biological systems. Organisational motifs underlying the structure of important biostructures can be imaged in a hydrated state in living samples or under conditions that are very close to living or physiological states. Among these biostructures, helically organised ones, such as chromatin-DNA, play a fundamental role in the way in which a cell functions. We are studying the structure of the sperm head of the octopus Eledone cirrhosa by means of CSLM and SFM. In particular we aim to study at different resolution levels the sperm head and its constituents and to use the very same sample as a large copy of chromatin itself. Earlier studies concluded that the rigid helical structure of the sperm head is due to its chromatin; probably this is true also for the shape of the head itself as found for several animal species. These studies reported that DNA begins to form 10 nm fibers during spermiogenesis and the fibers condenses further as the process evolves, but no model was obtained to describe the final arrangement of DNA. The possibility of performing such high resolution experiments could give useful hints to solve this problem.