Changes in The Cytochemical Properties Of Erythrocyte Nuclei Reactivated By Cell Fusion

1969 ◽  
Vol 4 (1) ◽  
pp. 71-87 ◽  
Author(s):  
L. BOLUND ◽  
N. R. RINGERTZ ◽  
H. HARRIS
Keyword(s):  
Hela Cell ◽  
Cell Fusion ◽  
Dry Mass ◽  
Nuclear Chromatin ◽  
Red Cell ◽  
Melting Profile ◽  
Nuclear Composition ◽  
Erythrocyte Nucleus ◽  
Rna And Dna ◽  
Deoxyribonucleoprotein Complex

When the nucleus of a chick erythrocyte is introduced into the cytoplasm of a HeLa cell it resumes the synthesis of RNA and DNA. This reactivation of the red cell nucleus is associated with an increase in volume and with changes in nuclear composition. These changes have now been studied by quantitative cytochemical techniques. During the process of reactivation the dry mass of the erythrocyte nucleus shows a marked increase which takes place largely before the replication of the DNA begins. Within 24 h of cell fusion, some erythrocyte nuclei already contain an increased amount of DNA, and 48 h after fusion many of them contain twice the normal diploid amount, thus indicating that they have replicated their DNA completely. The physical properties of the nuclear deoxyribonucleoprotein complex also change. The ability of the nuclear chromatin to bind acridine orange increases 4- to 5-fold well before the synthesis of DNA begins; and changes in the melting profile of the deoxyribonucleoprotein suggest that its structure is loosened. This view is also supported by the observation that the reactivity of the erythrocyte nuclei to the Feulgen stain is altered during the early stages of reactivation.

The Reactivation of the Red Cell Nucleus

1967 ◽  
Vol 2 (1) ◽  
pp. 23-28 ◽  
Author(s):  
H. HARRIS
Keyword(s):  
Hela Cell ◽  
Cell Nucleus ◽  
Rna Synthesis ◽  
Direct Relationship ◽  
Nuclear Volume ◽  
Red Cell ◽  
Primary Event ◽  
Rna And Dna ◽  
Nuclear Enlargement ◽  
Made In

When the nucleus of a mature hen erythrocyte is introduced into the cytoplasm of a HeLa cell it resumes the synthesis of RNA and DNA. This reactivation of the red cell nucleus in the heterokaryon is associated with a marked increase in its volume. There is a direct relationship between the volume of the nucleus and the amount of RNA which it makes. The nuclear enlargement is not a consequence of increased RNA synthesis, or of DNA synthesis: enlargement is the primary event, and the increase in RNA synthesis is determined by it. The possibility is considered that changes in nuclear volume may regulate not only the amount of RNA made in the nucleus but also the areas of chromatin on which it is made.

The use of cell fusion in the analysis of gene action (Summary only)

1970 ◽  
Vol 176 (1044) ◽  
pp. 315-317 ◽  
Keyword(s):  
Cell Fusion ◽  
Rna Synthesis ◽  
Sendai Virus ◽  
Recipient Cell ◽  
Fold Increase ◽  
Dry Mass ◽  
Culture Cell ◽  
Mouse Tissue ◽  
Tissue Culture Cell ◽  
Erythrocyte Nucleus

When, under the influence of inactivated Sendai virus, the nucleus of a mature hen erythrocyte is introduced into the cytoplasm of a human or mouse tissue culture cell, it resumes the synthesis of RNA and DNA. This reactivation of the red cell nucleus in the heterokaryon is associated with a marked increase in its volume. There is a direct relation between the volume of the nucleus and the amount of RNA that it makes. The nuclear enlargement is not the consequence of increased RNA synthesis, or of DNA synthesis: enlargement is the primary event, and the increase in RNA synthesis is determined by it. During the process of reactivation, the erythrocyte nucleus shows a five- to six-fold increase in dry mass which takes place largely before the replication of DNA begins. This increase is due to the passage of cytoplasmic proteins into the erythrocyte nucleus. The physical properties of the deoxyribonucleoprotein complex in the erythrocyte nucleus change as the nucleus enlarges. The ability of the nuclear chromatin to bind acridine orange and other intercalating dyes increases four- to fivefold; and changes in the melting profile of the deoxyribonucleoprotein indicate that its structure is loosened. It appears that, as the nucleus expands, more of the chromatin passes from a condensed to a dispersed state and more of it is transcribed. At the concentrations used to induce cell fusion, Sendai virus is haemolytic and rapidly lyses the nucleated erythrocytes. Fusion then takes place between the other cells in the combination and erythrocyte ghosts. The erythrocyte nucleus is thus introduced into the cytoplasm of the recipient cell without any appreciable contribution of erythrocyte cytoplasm. The reactivation of the hen erythrocyte nucleus is therefore achieved by signals emanating from human or mouse cytoplasm.

scholarly journals Intersexual Partial Diploids of Phycomyces

Genetics ◽  
2001 ◽  
Vol 158 (2) ◽  
pp. 635-641
Author(s):  
Bina J Mehta ◽  
Enrique Cerdá-Olmedo
Keyword(s):  
Dry Mass ◽  
Sexual Cycle ◽  
Genetic Constitution ◽  
Phycomyces Blakesleeanus ◽  
Carotene Content ◽  
Sexual Interaction ◽  
Sexual Stimulation ◽  
Nuclear Composition ◽  
Opposite Sex ◽  
Β Carotene

Abstract Sexual interaction between strains of opposite sex in many fungi of the order Mucorales modifies hyphal morphology and increases the carotene content. The progeny of crosses of Phycomyces blakesleeanus usually include a small proportion of anomalous segregants that show these signs of sexual stimulation without a partner. We have analyzed the genetic constitution of such segregants from crosses that involved a carF mutation for overaccumulation of β-carotene and other markers. The new strains were diploids or partial diploids heterozygous for the sex markers. Diploidy was unknown in this fungus and in the Zygomycetes. Random chromosome losses during the vegetative growth of the diploid led to heterokaryosis in the coenocytic mycelia and eventually to sectors of various tints and mating behavior. The changes in the nuclear composition of the mycelia could be followed by selecting for individual nuclei. The results impose a reinterpretation of the sexual cycle of Phycomyces. Some of the intersexual strains that carried the carF mutation contained 25 mg β-carotene per gram of dry mass and were sufficiently stable for practical use in carotene production.

Control of compensatory lung growth by adrenal hormones

1987 ◽  
Vol 253 (4) ◽  
pp. E343-E348 ◽  
Author(s):  
D. E. Rannels ◽  
H. W. Karl ◽  
R. A. Bennett
Keyword(s):  
Dry Mass ◽  
Lung Mass ◽  
Lung Growth ◽  
Unoperated Control ◽  
Adrenal Hormones ◽  
Compensatory Lung Growth ◽  
The Right ◽  
Rna And Dna ◽  
Left Pneumonectomy

The effects of adrenalectomy and/or in vivo treatment with hydrocortisone acetate (HCA;5 mg X kg-1 X day-1) on lung growth were investigated in control and pneumonectomized rats of 250 g body wt. Left pneumonectomy (day 0) initiated rapid hyperplastic growth of the right lung, which was unaffected by HCA. Similarly, HCA had no effect on lung growth in unoperated control animals. Two weeks after pneumonectomy, right lung dry mass, protein, RNA, and DNA were equal to that in both lungs of unoperated rats. Adrenalectomy 5 days before (day -5) left pneumonectomy increased the rate and extent of right lung growth, but did not change its hyperplastic character. Continuous HCA treatment (days -5 to 14) prevented the adrenalectomy-mediated increase in postpneumonectomy lung growth. "Early" HCA dosing (days -5 to 6) of adrenalectomized-pneumonectomized animals suppressed lung growth to the pneumonectomy level, but from days 7 to 14 growth accelerated to the adrenalectomized-pneumonectomized rate. Conversely, "late" HCA, initiated when adrenalectomized-pneumonectomized animals had restored normal total lung mass (days 6 to 14), quickly reduced right lung growth to rates typical of unoperated controls. The latter effects were not observed unless continuous steroid treatment was provided throughout this interval. The data support a role for glucocorticosteroids in modulation of the accelerated compensatory lung growth initiated by partial resection of the tissue.

scholarly journals Transfer of mouse nuclear envelope specific proteins to nuclei of chick erythrocytes during reactivation in heterokaryons with mouse A9 cells

1979 ◽  
Vol 37 (1) ◽  
pp. 97-107
Author(s):  
E. Jost ◽  
A. d'Arcy ◽  
S. Ely
Keyword(s):  
Nuclear Envelope ◽  
Cell Fusion ◽  
Nuclear Pore ◽  
Specific Staining ◽  
Antigen Uptake ◽  
Protein Uptake ◽  
Immunofluorescence Studies ◽  
Specific Proteins ◽  
Liver Nuclei ◽  
Erythrocyte Nucleus

When chick erythrocyte nuclei are introduced into the cytoplasm of mouse A9 cells by cell fusion, proteins present in a fraction of the mouse nuclear envelope begin to appear in the envelope of the chick erythrocyte. The protein uptake was examined using antisera raised in chickens against the 3 major polypeptides of the nuclear pore complex-fibrous lamina fraction from rat liver nuclei. In indirect immunofluorescence studies these antisera give a strong envelope-specific staining with various mammalian but not chicken cells. Eighteen hours after cell fusion the first murine antigens can be observed in the erythrocyte nucleus. Two days after cell fusion the vast majority of the erythrocyte nuclei in cell hybrids contain some antigen and by 3 days the fluorescence of the reactivated erythrocyte nuclei reaches a level comparable to that of the mouse A9 nuclei. The rate of appearance of fluorescence in the chick nuclei depends upon the ratio of A9 cytoplasm to chick nuclei. Antigen uptake by the erythrocyte envelope is inhibited when protein synthesis is blocked suggesting that synthesis of mouse antigen, rather than a redistribution, determines the velocity or erythrocyte envelope reactivation. The early uptake of nucleospecific protein into the reactivating chick erythrocyte may not require any alteration in the nuclear envelope.

scholarly journals GROWTH CHARACTERISTICS OF POLIOVIRUS IN HELA CELLS: NUCLEIC ACID METABOLISM

1957 ◽  
Vol 106 (5) ◽  
pp. 641-648 ◽  
Author(s):  
H. F. Maassab ◽  
Philip C. Loh ◽  
W. Wilbur Ackermann
Keyword(s):  
Nucleic Acid ◽  
Hela Cell ◽  
Hela Cells ◽  
Acid Metabolism ◽  
Growth Characteristics ◽  
Nucleic Acid Metabolism ◽  
Cytoplasmic Component ◽  
Dna Contents ◽  
Infectious Cycle ◽  
Rna And Dna

The RNA and DNA contents of the nucleus and cytoplasm of the HeLa cell were determined. The rates of incorporation of P32 into the various nucleic acid fractions were established for the ordinary HeLa cell maintained under a set of standard conditions. The changes in the rates of incorporation of P32 and in the amounts of RNA and DNA which occurred subsequent to infection with poliovirus were followed throughout the infectious cycle. These changes were correlated with the intracellular appearance of the newly formed virus. A net synthesis of RNA occurred in the cytoplasmic component of the cell. The increase was detectable 2 hours before the first appearance of demonstrable virus and reached a maximum (2.5 times normal) at 6 hours. Viral increase was not maximal before the 7th hour after infection.

Heme and dry mass formation during red cell development

1956 ◽  
Vol 10 (3) ◽  
pp. 752-754 ◽  
Author(s):  
B. Lagerlöf ◽  
B. Thorell ◽  
L. Åkerman
Keyword(s):  
Dry Mass ◽  
Cell Development ◽  
Red Cell ◽  
Mass Formation

scholarly journals Synthesis of Glycosidic (β-1′′→6, 3′ and 4′) Site Isomers of Neomycin B and their Effect on RNA and DNA Triplex Stability

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 580
Author(s):  
Lotta Granqvist ◽  
Ville Tähtinen ◽  
Pasi Virta
Keyword(s):  
Profile Analysis ◽  
Starting Material ◽  
Protecting Group ◽  
Melting Profile ◽  
Straightforward Manner ◽  
Neomycin B ◽  
Glycosyl Donor ◽  
Dna Triplex ◽  
Uv Melting ◽  
Rna And Dna

Glycosidic (β-1′′→6, 3′ and 4′) site isomers of neomycin B (i.e., neobiosamine (β-1′′→6, 3′ and 4′) neamines) have been synthesized in a straightforward manner. Peracetylated neomycin azide was used as a common starting material to obtain neobiosamine glycosyl donor and 6, 3′,4′-tri-O-acetyl neamine azide that after simple protecting group manipulation was converted to three different glycosyl acceptors (i.e., 5,6,4′-, 5,3′,4′- and 5,6,3′-tri-O-acetyl neamine azide). Glycosylation between the neobiosamine glycosyl donor and the neamine-derived acceptors gave the protected pseudo-tetrasaccharides, which were converted, via global deprotection (deacetylation and reduction of the azide groups), to the desired site isomers of neomycin. The effect of these aminoglycosides on the RNA and DNA triplex stability was studied by UV-melting profile analysis.

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