Topic
Ring centriole
About: Ring centriole is a research topic. Over the lifetime, 5 publications have been published within this topic receiving 124 citations.
Papers
TL;DR: Chromatin condensation begins with the formation of fibrous strands, then to lamellar plates which become folded and later twisted around the flagellar shaft, which eventually fuse to form a homogeneously dense nuclear tube.
Abstract: The fine structure of the spermatogonium, spermatocyte and spermatid of a marine snail, Littorina sitkana is described. The ring centriole (annulus) is formed from the distal centriole and it migrates to the base of the mitochondrial region where it lies in a joint-like structure which is formed by an area of invaginated plasma membrane. The distal and proximal centrioles are at first perpendicular to each other but the proximal centriole rotates to a position coaxial with the distal centriole and fuses with it. The peripheral doublet fibers are continuous between the two centrioles but the central fibers originate only in the distal centriole. The acrosome differentiates from the proacrosomal granule which is derived from a Golgi body. Microtubules, present at this stage, may assist acrosomal formation. Chromatin condensation begins with the formation of fibrous strands, then to lamellar plates which become folded and later twisted around the flagellar shaft. In the final stages the lamellae appear in cross section as concentric rings which eventually fuse to form a homogeneously dense nuclear tube.
60 citations
TL;DR: Electron micrographs from this study demonstrate several stages in the formation of the nuclear cap and acrosome by the Golgi system and Mitchondria, which at low magnifications appear to be “empty,” is shown by high magnification to contain dilated intracristal spaces.
Abstract: Electron micrographs from this study demonstrate several stages in the formation of the nuclear cap and acrosome by the Golgi system Formation of small vesicles from Golgi membranes, coalescence of these vesicles into the nuclear cap with concomitant fusion of contained granules to form the acrosome, is confirmed Mitchondria, which at low magnifications appear to be “empty,” are shown by high magnification to contain dilated intracristal spaces In many cases cristae are arranged parallel to the mitochondrial surface
In later spermiogenesis, appearance of the caudal sheath or manchette, proximal centriole, and terminal annulus (“ring centriole”) precede formation of the middlepiece and flagellum The presence of a series of parallel “annulated” membranes has been described The exact nature of these membranes, which appear to connect with the cisternae of the endoplasmic reticulum, remains to be investigated
56 citations
TL;DR: The cytoplasmic components of the male germ-cells of the rat and the mouse were examined by phase-contrast microscopy and most of the structures seen in fixed and stained preparations were identified.
Abstract: 1. The cytoplasmic components of the male germ-cells of the rat and the mouse were examined by phase-contrast microscopy. Most of the structures seen in fixed and stained preparations were identified. 2. The localized Golgi material of spermatocytes and spermatids consists of rods and filaments. The mitochondria are granular. 3. The archoplasmic vacuole, proacrosome, developing acrosome, proximal and distal centrioles, and the axial filament were visible. A structure which may be an accessory body was observed in spermatocytes and spermatids. The manchette was visible in late spermatids of the rat but not in those of the mouse. 4. Examination of spermatozoa revealed the acrosome, the post-nuclear cap, the mitochondrial sheath, the ring centriole, and the protoplasmic bead. A granule was sometimes visible in the neck region.
11 citations
TL;DR: Atypical spermatogonia, two cell lines develop in the testis of Strombus gigas with atypical spermatozoa that are spindle-shaped and the cytoplasm contains large dark granules, but no remnants of the vesicles with double membranes.
Abstract: Summary As in many prosobranchs, two cell lines develop in the testis of Strombus gigas. The typical spermatogenesis is similar to that described in many species. The spermatic cell development is characterized by cell divisions. Typical spermatogenesis leads to a mature spermatozoa with a column-shaped nucleus. The acrosome consists of an acrosomal rod covered by an acrosomal cone and topped by a hemispherical vesicle. The middle piece is made up of nine mitochondria helically arranged around the axoneme. A ring centriole is present between the middle piece and the flagellum. The tail contains the axoneme and glycogen granules. During atypical spermatogenesis no division of the cells is observed. The cytoplasm of atypical spermatogonia increases in size while the nucleus degenerates. In the cytoplasm dark granules and vesicles with double membranes develop. The mature atypical spermatozoa are spindle-shaped. The cytoplasm contains large dark granules, but no remnants of the vesicles with double membranes...
8 citations
TL;DR: The matrix of the proximal centriole contains an electron opaque granule which finally gives rise to the post nuclear cap, and in the late spermatids, merges with the postnuclear cap and forms a centrioles ring to which the flagellum is attached.
Abstract: SYNOPSIS
The centriole region of the rat consists of a proximal centriole, a ring centriole, and a post nuclear cap. The matrix of the proximal centriole contains an electron opaque granule which finally gives rise to the post nuclear cap. The ring centriole, in the late spermatids, merges with the post nuclear cap and forms a centriole ring to which the flagellum is attached.
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 1994 | 1 |
| 1976 | 1 |
| 1966 | 1 |
| 1962 | 1 |
| 1950 | 1 |