Chromatin irregular

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]... 

Theoretical models of chromatin fibers and their simulated AFM images support the view that extended chromatin fibers are irregular three-dimensional arrays of nucleosomes connected by straight linkers... 

Bacterial chromosomes are also extensively compacted into the nucleoid, but the chromosome appears to be much more dynamic and irregular in structure than eukaryotic chromatin, reflecting the shorter cell cycle and very active metabolism of a bacterial cell. 

DNA in eukaryotic chromosomes exists in a highly compacted form known as chromatin, a complex of DNA with a great variety of proteins. Five proteins called histones are present in large amounts (see table 25.2) and are believed to form a regularly repeating structural motif. The remaining proteins are present in smaller amounts and are irregularly distributed. 

The basic structural unit of chromatin is the nucleosome, in which 146 bp of DNA are wrapped 1.65 turns around the histone octamer (H2A, H2B, H3, H4)2. The co-crystal structure, a histone-octamer-DNA complex, shows that the DNA wraps tightly around a cylinder-like core of the histones. The DNA is arranged such that interactions between the N-terminal tails ofhistones and adjacent nucleosomes are possible. Furthermore, the DNA wrapping around the histone core is irregular, providing some flexibility in the structure, which may be relevant for remodeling of the nucleosome during transcription. 

The lung is an unusual site of involvement of mantle cell lymphoma, even in cases of advanced disease. The lymphoma is characterized by a monomorphic population of small- to intermediate-sized lymphoid cells with mild to marked irregular nuclei and relatively mature chromatin pattern without prominent nucleoli. There... 

Richmond and Phillips (1975) found in the case of Botrytis cinerea that the conidia of the fungi produced distorted germ tubes in the presence of benomyl. In most of the fungi, cell division differed from classical mitosis, the normal states of which were not seen clearly in any of the treated material. Chromosomes became visible at the prophase-metaphase, but they did not completely separate. Finally, the chromatin became stretched into long threads, daughter nuclei did not separate completely and chromatin was often present as irregular shaped masses. 

Soluble chromatin has been studied by a great variety of biophysical, biochemical, and imaging techniques (van Holde, 1979), and limitations in the interpretation of biophysical measurements on chromatin in solution have been discussed (van Holde and Zlatanova, 1995). It was pointed out that, because assemblies of nucleosomes tend to form irregular rather than symmetrical structures, their detailed conformation cannot be determined from such data. Direct imaging has the potential to describe the conformation of individual chromatin assemblies, regardless of their uniformity. 

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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