Chromatin granules

After administration of mercuric chloride to adult rat kidneys, several changes were found, for example, pars recta of the proximal tubular segment showing fragmentation and disruption of the plasma membrane, basophilic staining, vesiculation and disruption of endoplasmic reticulum and other cytoplasmic membranes, mitochondrial swelling, loss of mitochondrial dense granules and condensation of nuclear chromatin [223-225]. 

Lymphocytes White blood cells formed in the body s lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each) those with characteristics of neither major class are called null cells. [NIH]... 

Fig. 4. An apoptotic peripheral blood eosinophil observed under EM. The apoptotic cell displays the characteristic condensation of nuclear chromatin into large, electron-dense masses surrounding the central, relatively electron-lucent nuclear matrix. The swelling and breakage of plasma and perinuclear membranes and the release of the contents of granules from swollen, enlarged, electron-lucent granule containers within secretory cells are also observed. A single osmiophilic lipid body is found in the cytoplasm (x 18,500) (D6). Reproduced with permission from Dvorak, A. M., Images in clinical medicine, an apoptotic eosinophil. N. Engl. J. Med. 340, 437 (1999).

Neutrophil. A granular leukocyte, having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules. Neutrophils have the properties of chemotaxis adherence to immune complexes, and phagocytosis. 

The final principal component of the cell is the nucleus. This is located in the center of the cell and is surrounded by a double membrane, the outer layer being derived from the ER of the cytoplasm and the inner layer coming from the nucleus itself. The two leaflets of the double membrane are fused in places, producing nuclear pores that enable the transfer of macromolecules from the cytoplasm to the nucleus. Two important components of the nucleus are chromatin and the nucleolus. Chromatin represents polymers of DNA complexed with protein. The nucleolus is a complex substructure, composed of ribonucleoprotein granules, that controls the synthesis of RNA destined to form the ribosomes of the cytoplasm. Cells engaged heavily in protein synthesis have... 

When we examine a cell in its resting stage we find the nucleus more or less spherical in shape, surrounded by a nuclear membrane and containing a nuclear network, nuclear sap and one or more nucleoli. The nuclear network consists of a colorless network of linin adhering to which are numerous minute granules called chromatin which take the stain of a basic dye. Surrounding the nucleus is the cytoplasm. 

Flgure 12.1 Electron micrograph of an apoptotic human neutrophil showing the characteristic chromatin aggregation, prominent nucleolus and dilated cytoplasmic vacuoles. Note that the cell membrane is intact and the granule structure appears normal. (EM taken by Jan Henson), (x 11 000). 

Fig. 3. An apoptotic pancreatic acinar cell from a rat treated with 1-cyano-2-hydroxy-3-butene. The cell has a rounded morphology and has lost all but a few of its zymogen granules ( ). There is early condensation of nuclear chromatin (small arrows) around the margins of the nuclear envelope and the nucleolus (nu) is partially segregated from the chromatin. Most mitochondria (M) are normal in morphology, although one swollen one (large arrow) with microhemiation is present. Bar = 5 pm.

A cytoplasmic extract consists of a crude egg lysate containing cytosol, membrane vesicles (MVs), ribosomes, and occasional mitochondria, but is free of pronuclei, essentially all yolk granules, and other large cytoplasmic inclusions. Unfertilized egg extracts support only partial chromatin decondensation (Cameron and Poccia, 1994), whereas extracts from fertilized eggs support full chromatin decondensation and nuclear envelope assembly (Zhang and Ruderman, 1993 Cameron and Poccia, 1994 Collas and Poccia, 1995a,b). 

Fig. 9. The RNP granules in the Balbiani rings of the Chironomus salivary gland. A. the region of a Balbiani ring numerous particles are visible B., C. the particles in the region of chromosome one can see the joining strands between the particles and chromatin material D. E. the particles moving across the pores of the nuclear membrane. A, X22,500 B, X49,500 C to E, X90,000. (From Stevens and Swift. 1966. J. Cell Biol., 31 55-77.)...

Fig. 11. A. Typical aspect of a cluster of interchromatin granules in normal rat liver nucleus. Glutaraldehyde>Epon, EDTA method chr, bleached chromatin ->, perichromatin granules fibrils ig interchromatin granules. X42,300. B. Cluster of interchromatin granules in the nucleus of an adrenal cortex cell from normal rat. Glutaraldehyde-Epon, EDTA method. The granules are irregularly shaped and have a striking tendency to form chainlike aggregates. small rods may be found,...

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