Phosphorus compounds in the cell. 4. The incorporation of radioactive phosphorus into liver cell fractions

Smellie, R. M. S.; McIndoe, W. M.; Logan, R.; Davidson, James; Dawson, I. M. P.

doi:10.1042/bj0540280

Cited by 80 publications

(10 citation statements)

References 13 publications

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“…The amount of P3* incorporated into the total RNA is 17.8 times greater than that in DNA. This phenomenon generally has been found for resting cells (Smellie et at., 1953). I n the experimental period studied, from 0 to 7 hours, it was found that the cell number, composition with regard to DNA and RNA, and the pattern of incorporation of the isotope did not vary significantly.…”

Section: The Nucleic Acid Composition Of Normal Hela Cells and Their supporting

confidence: 76%

“…The amounts of nuclear RNA and cytoplasmic RNA were quite similar. The uptake of P32 into various nucleic acid fractions follows the pattern of cells from other species described previously (Marshak, 1948, Smellie et al, 1953. The highest rate of incorporation is seen in the nuclear RNA, followed by the cytoplasmic RNA, and DNA.…”

Section: The Nucleic Acid Composition Of Normal Hela Cells and Their supporting

confidence: 75%

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Nucleic Acid Metabolism of Virus‐infected Hela Cells*

Maassab

Ackermann

1959

Annals of the New York Academy of Sciences

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The study of the chemistry of virus-infected cells cannot yet claim a molecular interpretation for the genesis of the viral cytopathic effect. However, many striking observations have been made that must be accounted for in any molecular theory of viral cytopathology. From the viewpoint of comparative virology, the most consistent viral-induced aberrations involve the nucleic acids. The findings that we describe here concern the several classes of these important compounds, their relations to the cell architecture, and their dynamics relative to a single cycle of infection. These experiments with HeLa cells and poliovirus are part of a continuing investigation and are contributions made in collaboration with our colleagues. Some results have been published; others have not been made available previously.Part of the record in the literature (Payne et al., 1958) describes how a single cycle of infection of monolayers of HeLa cells may be effected with high concentrations of poliovirus. It suffices here to say that interpretations at the cellular level of the present observations made on multicellular cultures have been justified.The first experiments concern the stability of the cell structure after infection, particularly in regard to those elements that will be considered in the metabolic studies. Transudation PhenomenonHeLa cells are readily labeled with P3* by allowing them to grow in a medium containing radioactive inorganic phosphate. The P32 is incorporated into a number of large molecules and structures such as the nucleic acids, microsomes, and mitochondria. When such labeled cells are transferred to unlabeled maintenance medium (Scherer, 1953) and incubated, some of the radioactive phosphorus leaks from the cell. Initially, the process is rapid, but it soon subsides and, by 5 hours, an equilibrium seems to be established between this exchangeable phosphate of the cell and that of the medium. After this time the P32 of the medium ceases to rise and remains constant (FIGURE 1).When poliovirus is added to such a culture of labeled cells, the process of P 3 2 exchange closely parallels that of the control until the sixth hour of infection. At this time, the curves for the release of Pa2 diverge (FIGURE 1). Progressively, the transudation of labeled cellular elements is accelerated in the infected culture. A preliminary examination of this transudate shows it to be composed of both acid-soluble and acid-insoluble elements. The soluble fraction is a complex mixture of nucleotides, nucleosides, and inorganic phosphate.

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Section: The Nucleic Acid Composition Of Normal Hela Cells and Their supporting

confidence: 76%

Section: The Nucleic Acid Composition Of Normal Hela Cells and Their supporting

confidence: 75%

Nucleic Acid Metabolism of Virus‐infected Hela Cells*

Maassab

Ackermann

1959

Annals of the New York Academy of Sciences

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“…There are in the cytological and cytochemical literature a number of less detailed morphological observations on microsomes isolated either from liver (33,59,(61)(62)(63) or from other animal tissues (33,59). According to these observations the microsomes are small vesicles (59,61), granules (59), particles (62), or aggregates of particles (63) ranging in size from 10 to 250 m#.…”

Section: Liv~ii Micro Som_esmentioning

confidence: 99%

“…According to these observations the microsomes are small vesicles (59,61), granules (59), particles (62), or aggregates of particles (63) ranging in size from 10 to 250 m#. Some observers found the microsome population rather homogeneous (62,63), whereas others stressed its heterogeneity (59). It is assumed that discrepancies between these conclusions and the findings here reported are due primarily to differences in preparatory techniques for electron microscopy.…”

Section: Liv~ii Micro Som_esmentioning

confidence: 99%

Liver Microsomes

Palade

Siekevitz

1956

The Journal of Cell Biology

891

223

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Rat liver, liver homogenates, and microsome fractions separated therefrom were examined systematically in the electron microscope in sections of OsO4-fixed, methacrylate-embedded tissue and pellets. It was found that most microsomes are morphologically identical with the rough surfaced elements of the endoplasmic reticula of hepatic cells. They appear as isolated, membrane-bound vesicles, tubules, and cisternae which contain an apparently homogeneous material of noticeable density, and bear small, dense particles (100 to 150 A) attached to their outer aspect. In solutions of various osmolar concentrations they behave like osmometers. The findings suggest that they derive from the endoplasmic reticulum by a generalized pinching-off process rather than by mechanical fragmentation. The microsome fractions contain in addition relatively few vesicles free of attached particles, probably derived from the smooth surfaced parts of the endoplasmic reticula. Dense, peribiliary bodies represent a minor component of the same fractions. The microsomes derived from 1 gm. wet weight liver pulp contained (averages of 10 experiments) 3.09 mg. protein N, 3.46 mg. RNA (RNA/protein N = 1.12), and 487 µg. phospholipide P. They displayed DPNH-cytochrome c reductase activity and contained an alcohol-soluble hemochromogen. The microsome preparations proved resistant to washing and "aging." Treatment with versene and incubation with ribonuclease (30 minutes at 37°C.) resulted in appreciable losses of RNA and in partial or total disappearance of attached particles. Treatment with deoxycholate (0.3 to 0.5 per cent, pH = 7.5) induced a partial clarification of the microsome suspensions which, upon centrifugation, yielded a small pellet of conglomerated small, dense particles (100 to 150 A) with only occasionally interspersed vesicles. The pellet contained ∼80 to 90 per cent of the RNA and ∼20 per cent of the protein N of the original microsomes. The supernatant accounted satisfactorily for the materials lost during deoxycholate treatment. The findings suggest that the microsomal RNA is associated with the small particles whereas most of the protein and nearly all of the phospholipide, hemochromogen, and DPNH-cytochrome c reductase activity are associated with the membrane or content of the microsomes.

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“…This heterogeneity reveals itself either as differences among various fractions of the whole cellular R N A (6), or as differences between nuclear and cytoplasmic R N A (7-9), or as differences among the RNA's of various cytoplasmic fractions, e.g. the mitochondrial, microsomal, and final supernatant fractions (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). Our work extends this line of inquiry towards recently recognized cell fractions and subfractions, many of which consist of ribonucleoprotein (RNP) particles.…”

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confidence: 99%

A Cytochemical Study on the Pancreas of the Guinea Pig

Siekevitz

Palade

1959

The Journal of Cell Biology

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Five ribonucteoprotein (RNP) fractions were isolated from the postmitochondrial supernatant of the pancreas of the guinea pig. Two were obtained from the microsomes which, by deoxycholate (DOC) treatment, were subdivided into a DOC-soluble and a DOC-insoluble fraction. The latter was taken to represent attached RNP particles. Two other fractions obtained from the microsomal supernatant supposedly represent free RNP particles existing as such in the cytoplasm, while a third fraction resisted sedimentation for 20 hours at 105,000 g and is considered to be a soluble nucleoprotein. These fractions exhibited different RNA/ protein ratios and also different RNA turnover patterns, as determined after in vivo labelling with adenine-8-C 14. However, little discernible differences could be detected in the nucleotide composition of the RNA moieties of these RNP fractions.Amino acid-"activating" enzymes were found to occur in the fraction containing the soluble nucleoproteins.The discussion focuses on the relationships between these fractions and protein synthesis in the pancreas, using data given in this and a previous paper, and data contained in the literature.In a detailed cytochemical investigation of the pancreas of the guinea pig (1-5), we have found that it is possible to separate several cytologically distinct types of nucleoprotein particles (2, 5) derived mostly from the cytoplasm of the exocrine cells of this organ. Since we have already studied (5) the in vivo turnover of the proteins of these particles, we have decided to determine, also in vivo, the turnover of their nucleic acid moiety.In this paper we present our findings on this point together with additional data pertaining to the chemical composition of the particles.The metabolic heterogeneity of the ribonudeic acid (RNA) at cellular and subcellular levels has

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Phosphorus compounds in the cell. 4. The incorporation of radioactive phosphorus into liver cell fractions

Cited by 80 publications

References 13 publications

Nucleic Acid Metabolism of Virus‐infected Hela Cells*

Nucleic Acid Metabolism of Virus‐infected Hela Cells*

Liver Microsomes

A Cytochemical Study on the Pancreas of the Guinea Pig

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