منابع مشابه
Isolated Chromosomes
The chromatin threads, which we described briefly several years ago (1), have since then been studied carefully both morphologically and chemically. We now consider these microscopic threads of chromatin to be isolated chromosomes (2). From certain animal cells such masses of isolated chromosomes can be prepared that, with respect to quantity of material available, no special methods are requir...
متن کاملAn Electron Microscope Study of Isolated Chromosomes.
HE limitation in the penetrating power of electrons is one of the most T serious obstacles in the study of chromosomes by electron microscopy. Chromosomes are generally larger than 0.2p in diameter and are nearly opaque to electron penetration. At various stages of the nuclear cycle, however, chromosomes change their size and shape. Dividing chromosomes are generally largest and “resting” chrom...
متن کاملThe Composition and Structure of Isolated Chromosomes
1. The preparation of isolated chromosomes from liver, kidney, and pancreas has been described. 2. It has been shown that there is no gross cytoplasmic contamination in these preparations. 3. In a microscopic study of isolated chromosomes the same chromosomes have been found in different tissues of the same organism. Since individuality is one of the main characteristics of chromosomes, there c...
متن کاملThe Chemical Composition of Isolated Chromosomes
By means of 1 M NaCl isolated lymphocyte chromosomes can be separated into two fractions, each of which contains nucleoprotein. The fraction soluble in M NaCl consists largely of desoxyribose nucleohistone, and constitutes 90 to 92 per cent of the mass of the chromosome. The insoluble residue (the residual chromosome is a coiled thread containing some 12 to 14 per cent of ribose nucleic and abo...
متن کاملUltrastructure of polytene chromosomes of Drosophila isolated by microdissection.
Drosophila polytene chromosomes prepared by a new micromanipulative procedure, which avoids acid squashing, have been examined at the ultrastructural level in the electron microscope. Puffs at 2B, 68C, 74EF, 75B and 85EF, have been examined in some detail, along with the chromocentre and various interbands. The ultrastructure of these chromosomes, which have never been exposed to acid protein d...
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ژورنال
عنوان ژورنال: Journal of General Physiology
سال: 1947
ISSN: 1540-7748,0022-1295
DOI: 10.1085/jgp.31.1.1