Chromatin Sentence Examples
The chromatin is practically identical with nuclein.
If, from whatever cause, any of the chromatin loops belonging to the functional order be lost the descendants of such a cell, being unable to restore these loops, will be minus the functional attributes associated with the lost elements.
The chromatin substance increases in amount; the thread stains moie deeply, and in most cases presents a homogeneous appearance.
It forms a part of the 1mm or plastin network of the nucleus and may become impregnated with varying quantities of chromatin stored up for use in the formation of the chromosomes and other nuclear activities.
The eukaryotic solution to the compaction problem is called chromatin, a complex of DNA and structural proteins.Advertisement
Each chromosome is really a very long molecule of DNA wound up and coiled around special proteins to form chromatin.
On the spreads, different states of dispersed chromatin have been revealed.
The problem is a very difficult one and cannot be regarded as definitely settled, but it is difficult to understand why all this additional complexity in the division of the nucleus should be necessary if the final result is only a quantitative separation of the chromatin.
Insulators are DNA elements that defend genes from surrounding chromatin by setting the boundaries of independent chromatin domains.
The existing concept - that open chromatin is an absolute requirement for gene activity - is not supported by this study.Advertisement
The chromatin diminution is the elimination of an inactive chromatin from a genome.
This would in effect establish a boundary between inactive condensed chromatin and active open chromatin.
The study of chromatin condensation is a major focus of our apoptosis studies.
The thickness of the axial chromatin fibril is 6-10 nm.
We have employed yeast genetics along with biochemical approaches to uncover remodeling of extensive chromatin domains.Advertisement
Chromatin containing acetylated histones is open and accessible to transcription factors, and the genes are potentially active.
Jacqueline is currently supported by the AICR to study the control of DNA methylation by a chromatin insulator.
The nuclei of the cells show pleomorphism, with variation in size, shape and chromatin staining pattern.
Some observers consider that it represents a longitudinal half of the original segment of the spireme, others that it is a half of the segment produced by transverse division by means of which a true qualitative separation of the chromatin is brought about.
On the other hand, the complex structure of the nucleus with its separate units, the chromosomes, and possibly even smaller units represented by the chromatin granules, and the means taken through the complex phenomena of mitosis to ensure that an exact and equal division of the chromosomes shall take place, emphasizes the importance of the nucleus in heredity.Advertisement
The only evidence we have in pathology of living structures in which apparently a differentiation into cell-body and nucleus does not exist, is in the case of bacteria, but then there comes the question whether they may not possess chromatin distributed through their substance, in the form of metachromatic points, as is the case in some infusoria (Trachelocerca, Gruber).
When fixed and stained this granular mass is resolved into a more or less distinct granular network which consists of a substance called Linin, only slightly stained by the ordinary nuclear stains, and, embedded in it, a more deeply stainable substance called Chromatin.
He thinks it may possibly originate in the vacuolization of the central region, and the accumulation of chromatin granules therein.
It is thought that the loops are formed by special DNA-binding proteins that are attached to specific regions of the 30 nm chromatin fiber.
The Structure of the Nucleus.In the living condition the resting nucleus appears to consist of a homogeneous ground substance containing a large number of small chromatin granules and one or more large spherical granulesnucleolithe whole being surrounded by a limiting membrane which separates it from the cytoplasm.Advertisement
The central body seems to consist merely of a spongy mass of slightly stainable substance, more or less impregnated with chromatin, which divides by constriction.
The chromatin is distributed throughout the cytoplasm in the form of granules which may be regarded as a distributed nucleus corresponding to what Hertwig has designated, in protozoa, chromidia.
Oertel finds an explanation of this want of complete celldifferentiation, loss of function, and acquired vegetative activity in the non-homogeneous character of the nuclear chromatin elements of the cell, and maintains that the different properties of the cell are carried and handed down by the different orders of chromatin loops.
That these granules consist of a material similar to the chromatin of the nucleus of higher forms is very doubtful, and the comparison with the nucleus of more highly organized cells rests on a very slender basis.
As they pass into this position they undergo a longitudinal splitting by which the chromatin in each chromosome becomes divided into equal halves.
It is clear, however, that an equal quantitative division and distribution of the chromatin to the daughter cells is brought about; and if, as has been suggested, the chromatin consists of minute particles or units which are the carriers of the hereditary characteristics, the nuclear division also probably results in the equal division and distribution of one half of each of these units to each daughter cell.
Oertel thinks that in man we have these two different functions carried on by the one nucleus containing both chromatin orders.
In the yeast cell the nucleus is represented by a homogenous granule, probably of a nucleolar nature, surrounded and perhaps to some extent impregnated by chromatin and closely connected with a vacuole which often has chromatin at its periphery, and contains one or more volutin granules which appear to consist of nucleic acid in combination with an unknown base.
Chromatin is contained in the central part together with granules known as volutin, the function of which is unknown.