Chromatin

The Cell Nucleus: Chromatin, Part A is a collection of papers that deals with the fundamental research involving cellular responses to environmental stimuli and stress. One paper describes the ultra-structural organization of chromosomes and certain eukaryotic chromatin fractions as seen by a scanning electron microscope. The researcher investigating chromatin three-dimension ultra-structure is presented with two choices to address the technical limitations of SEM at different levels, namely, (1) electron microscope modality and (2) specimen preparation procedures. Another paper explains the extensive postmortem changes in properties occurring in nuclear preparations during purification and handling. The analysis of the digestion products when mammalian nuclei are digested with endogenous and exogenous nucleases can show the organization structure of the cell nucleus. When treated with Ca-Mg or micrococcal endo-nuclease, the different nuclear or chromatic preparations present near identical digestion patterns. Another paper reviews the occurrence of phase-specific nuclear proteins in the Physarum mitotic cycle, as well as their possible role in the control of DNA replication order in Physarum. The collection can prove valuable to bio-chemists, cellular biologists, micro-biologists, developmental biologists, and scientists involved in cellular investigations.