Biomaterial Database

Ultrastructural and functional variations in the spermatid nucleolus during spermiogenesis in the mouse. 1985

C Mirre, and B Knibiehler

The localization, structure, and activity of the nucleolus-organizers (NORs) were studied during spermiogenesis in the mouse by light and electron microscopy procedures including NOR-silver-staining and actinomycin D treatment. After the two meiotic divisions the NORs resume their activity during the Golgi phase of spermatid differentiation (steps 1-3), and the nucleolus displays a specific 'padlock' structure containing the fibrillar components of an active nucleolus. This activity drops during the cap phase (steps 4-7) during which the nucleolus undergoes a segregation process of its components. No nucleolar structure is visible during the acrosomal and maturation phases of spermatid differentiation.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D009697	Nucleolus Organizer Region	The chromosome region which is active in nucleolus formation and which functions in the synthesis of ribosomal RNA.	Nucleolar Organizer,Nucleolar Organizers,Nucleolus Organizer Regions,Organizer Region, Nucleolus,Organizer Regions, Nucleolus,Organizer, Nucleolar,Organizers, Nucleolar,Region, Nucleolus Organizer,Regions, Nucleolus Organizer
D002466	Cell Nucleolus	Within most types of eukaryotic CELL NUCLEUS, a distinct region, not delimited by a membrane, in which some species of rRNA (RNA, RIBOSOMAL) are synthesized and assembled into ribonucleoprotein subunits of ribosomes. In the nucleolus rRNA is transcribed from a nucleolar organizer, i.e., a group of tandemly repeated chromosomal genes which encode rRNA and which are transcribed by RNA polymerase I. (Singleton & Sainsbury, Dictionary of Microbiology & Molecular Biology, 2d ed)	Plasmosome,Cell Nucleoli,Nucleoli, Cell,Nucleolus, Cell,Plasmosomes
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013087	Spermatids	Male germ cells derived from the haploid secondary SPERMATOCYTES. Without further division, spermatids undergo structural changes and give rise to SPERMATOZOA.	Spermatoblasts,Spermatid,Spermatoblast
D013091	Spermatogenesis	The process of germ cell development in the male from the primordial germ cells, through SPERMATOGONIA; SPERMATOCYTES; SPERMATIDS; to the mature haploid SPERMATOZOA.	Spermatocytogenesis,Spermiogenesis
D051379	Mice	The common name for the genus Mus.	Mice, House,Mus,Mus musculus,Mice, Laboratory,Mouse,Mouse, House,Mouse, Laboratory,Mouse, Swiss,Mus domesticus,Mus musculus domesticus,Swiss Mice,House Mice,House Mouse,Laboratory Mice,Laboratory Mouse,Mice, Swiss,Swiss Mouse,domesticus, Mus musculus