Incorporation Of Radioactive Phosphorus Research Articles

Effect of infection with iridovirus type 6 on invertebrate cell phospholipids

Summary Iridovirus type 6 induced a modification in the phospholipids of invertebrate cells early in the infection cycle. This was shown by following the incorporation of radioactive phosphorus into the whole-cell phospholipids and analysing the percentages of the different phospholipid components after viral infection. We compared the results obtained on different permissive and non-permissive invertebrate cell lines. These results showed, with the whole-cell cultures used, that the viral infection led to a decrease in the phosphorus incorporation into the cell phospholipids and to a stimulation of the cell phosphatidylcholine synthesis.

A Method for Eliminating the Contribution of Agrobacterium tumefaciens to Studies of Nucleic Acid Biosynthesis in Crown Gall Tumors

A procedure is described that permits the use of radiotracer methods for examining crown gall tumors in the presence of the initiating agent Agrobacterium tumefaciens. On the basis of sensitivity testing using the disc diffusion technique and the minimum inhibitory concentration procedure and incorporation of radioactive phosphorus into nucleic acids, it was determined that A. tumefaciens was most sensitive to tetracycline, oxytetracycline, and methacycline. It was further demonstrated that nucleic acid synthesis in tumor tissue from four representative plants including tomato (Lycopersicum esculentum L.), Bryophyllum daigremontiana (Hamet and Perrier), pinto beans (Phaseolus vulgaris L.), and carrot (Daucus carota L.) was unaffected by a concentration of tetracycline (50 mug/ml) which completely inhibited nucleic acid synthesis in the bacterium. On this basis a procedure is described which first eliminates surface contamination and then uses tetracycline to nullify the contribution of A. tumefaciens in radioactive studies using tumors initiated by this bacterium.

Maturation of chloroplast rRNA in Euglena gracilis

The incorporation of radioactive phosphorus into RNA of greening Euglena labels 21 S and 25 S cytoplasmic rRNA, 16 S and 23 S chloroplast rRNA (0.55 and 1.1 × 10 6 dalton), and two minor “p 16” and “p 23” chloroplast species, slightly larger than 16 S and 23 S RNA (0.62 and 1.2 × 10 6 dalton). Their role of precursors for 16 S and 23 S RNA has been demonstrated by quantitative conversion of “p 16” to 16 S RNA.

無蛋白食飼育時の筋肉核酸量およびその<sup>32</sup>P取込み量の経時的変化

無蛋白食飼育時の筋肉核酸量およびその<sup>32</sup>P取込み量の経時的変化

Nucleotide metabolism in Ehrlich ascites carcinoma cells

Incubation of Ehrlich ascites tumour cells with radioactive glucose leads to rapid labelling of the nucleotides of RNA. Most of the label ( > 90%) is associated with the ribose moiety and the extent of labelling of the CMP of RNA is less than one-tenth that of the other three nucleotides. When 32P 1 is used as a precursor the specific activities of the four nucleotides are quite similar. It is proposed that the interconversion of nucleoside and nucleotide plays a major role in the incorporation of radioactive phosphorus into RNA. Preliminary studies suggest that inhibition of uridine kinase by CTP may be important in regulating pyrimidine nucleotide levels and possibly nucleic acid synthesis.

Phospholipid metabolism in mitochondria and microsomes of rabbit liver during development

The protein, total phospholipid, phosphatidyl inositol, sphingomyelin, phosphatidyl choline, phosphatidyl serine, and phosphatidyl ethanolamine concentrations of mitochondria and microsomes have been determined m the liver of −12, −9, 0, +2, +9, and +14-day-old rabbits. The pattern of growth and development of the liver and liver mitochondria and microsomes was demonstrated by increased wet weight of the liver, by increased mitochondrial and microsomal protein concentration per whole tissue, and by increased mitochondrial and microsomal phospholipid phosphorus per whole tissue. The protein concentration per g of wet tissue was observed to increase in both mitochondria and microsomes after birth. The concentration of total and individual phospholipid phosphorus per mg of mitochondrial protein does not change during development and would suggest that the pattern of mitochondrial phospholipids has been established prior to the development interval studied (−12 to +14 days). This observation would suggest that the duplicating machinery for the phospholipids of membranes of rabbit-liver mitochondria has already been developed 12 days before birth. However, this is not true for the microsomes. The concentration of phospholipid phosphorus per mg of microsomal protein showed an increase in the amount of total phospholipid and phosphatidyl choline before birth and phosphatidyl ethanolamine and phosphatidyl inositol after birth. The incorporation of radioactive phosphorus into the phospholipid fractions of mitochondria and microsomes seemed to indicate a relatively constant rate of synthesis during development.

The incorporation of radioactive phosphorus into individual liver phosphatides of rats

1. 1. The incorporation of isotopic orthophosphate ( 32P) into individual rat-liver phosphatides in vivo has been studied over a 22-h period. 2. 2. The two phosphatides which were most heavily labeled at the earliest time studied (5 min) were cardiolipin and phosphatidylinositol. 3. 3. Phosphatidylethanolamine rapidly incorporated 32P reaching its peak relative specific activity 10 min after isotope administration, and remained heavily labeled throughout the 22-h period. 4. 4. The incorporation of 32P into lecithin was extremely slow and exhibited a higher relative specific activity than that for phosphatidylethanolamine only at the later time intervals (16 h). 5. 5. Sphingomyelin was the only phosphatide which exhibited a biphasic pattern of 32P incorporation. 6. 6. Ethionine produced radical changes in 32P incorporation into rat-liver phosphatides. A striking elevation in 32P uptake into lecithin and a sharp drop in labeling phosphatidyl ethanolamine was observed in animals receiving ethionine 24 h previously.

Incorporation of radioactive phosphorus in heart muscle of rats with implanted brain tumors in various stages of development

The character of radiophosphorus incorporation into the phosphorus-containing fraction of the cardiac muscle was studied during various stages of the development of transplanted glial tumors in rats. An intensified P32 accumulation was ascertained radiometrically in the cardiac muscle at the initial period (the 5th day) of development of the tumor implant chiefly at the expense of its incorporation into the phospholipids. Later, on the 10th and 14th–15th days of tumor development, there was a progressive reduction in P32 content in the cardiac muscle and in its phosphorus-containing fractions, with some rise in the intensity of P32 incorporation into the acid soluble fraction. The results of histoautoradiographic investigations corresponded to the radiometric findings.

Studies on the Phosphorus Metabolism in Tabacco Plant (Part 2) : Incorporation of Radioactive Phosphorus into Phosphorus Compounds during the Ripening Stage of Tabacco Leaves

Studies on the Phosphorus Metabolism in Tabacco Plant (Part 2) : Incorporation of Radioactive Phosphorus into Phosphorus Compounds during the Ripening Stage of Tabacco Leaves

The incorporation of radioactive phosphorus in the leucocyte during the extrusion of protein induced by staphylococcal leucocidin.

Incubation with leukocidin stimulates the incorporation of P/sup 32/ into the adenosine tri- and di-phosphate and guanosine tri- and di-phosphate of the leukocyte. Incubation with leukocidin does not increase the permeability of the leukocyte to orthophosphate and in the presence of P/sup 32/ does not increase the radioactivity of the intracellular orthophosphate. In the presence of fluoride, iodoacetate, or arsenate the incorporation of P/sup 32/ into the lipids and nucleotides of the leukocidin-treated leukocyte is partially inhibited. The extrusion of BETA -glucuronidase is not affected under these conditions. Omission of calcium from the medium stimulates the incorporation of P/sup 32/ into the lipids of the leukocidin-treated leukocyte and reduces the amount of incorporation into the nucleotides. Either component of leukocidin adsorbed on the leukocyte can be neutralized by antibody. Addition of antibody to the leukocidin-treated leukocyte does not inhibit the incorporation of P/sup 32/ into the nucleotides. Treatment with leukocidin decreases the rate of loss of radioactivity from the nucleotides of leukocytes labeled with P/sup 32/ and suspended in a medium of low specific radioactivity. Treatment with leukocidin reduces the amount of STAC/sup 14/!adenine incorporated into adenosine triphosphate and the amount of STAC/sup 14/!acetate incorporated into the lipids of themore » cell. It is suggested that the stimulation of incorporation of P/sup 32/ in the leukocidin-treated leukocyte does not result from- an increased rate of turnover of any phosphorus compound of the cell but can result from direct utilization at the cell surface of the external orthophosphate. (auth)« less

STUDIES ON GRANULATION TISSUE

A morphological and biochemical study of granulation tissue in wound healing was reported, using the circular excised wound of the dorsal skin of male adult mice.Argyrophilic fibrils appeared first on the 6th day after the excision. After the 8th and subsequent days, prominent fibrogenesis was marked. Ribonucleic acid was most intensely demonstrated on the 8th and the 10th day. Alkaline phosphatase was observed only in the fibrotic area after the 8th day.Neutral salt soluble collagen may not integrate in the newly deposited argyrophilic collagen fibrils in the 8th day granulation tissue. The neutral salt soluble collagen would exist in a dispersed or submicroscopic fibrillar state in the granulation tissue.Acid soluble collagen might represent the bulk of newly deposited col-lagen fibrils.PAS positivity of collagen fibers gradually decreased with maturation of fibers.Biochemical study revealed that the neutral salt soluble collagen already appeared on the 6th day in considerable amounts. All collagen fractions gradually increased thereafter, and remarkable accumulation of insoluble collagen was recognized on the 10th and the 12th day. The ratio of neutral salt soluble and insoluble collagen to the total collagen changed inversely. Acid soluble collagen showed no remarkable change.The content of desoxyribo- and ribonucleic acid increased up to the 8th day and then gradually decreased in the granulation tissue.It has been shown that the incorporation of radioactive phosphorus into the nucleic acids made two peaks. The first was noted on the 4th day, when the leucocytic infiltration was prominent, and the second was on the 8th and the 10th day, when the active proliferation of fibroblasts and synthesis of collagen precursor were remarkable.The possible significance of these results is discussed.

Incorporation of radioactive phosphorus into the ribonucleic acid of subfractions derived from guinea-pig-liver microsomes.

Incorporation of radioactive phosphorus into the ribonucleic acid of subfractions derived from guinea-pig-liver microsomes.

Incorporation of phosphorus-32 and mutagenesis during spermatogenesis in Drosophila.

RADIOACTIVE isotopes may be used as a source of radiation not only for tracing biological processes but also for influencing them. The following is a summary of the results of some experiments utilizing a combination of these two principles, in that the incorporation of radioactive phosphorus has been followed during spermatogenesis in Drosophila melanogaster, and at the same time the genetic effect of the radioactive decay of the phosphorus atoms has been measured. The genetic and metabolic effects of the decay of phosphorus-32 have been investigated by several authors in different materials: in Drosophila1–4, in Habrobracon5, and in micro-organisms6.

Phosphorus metabolism of the adrenal gland: effect of cold stress on the labeling of phospholipid and RNA nucleotides with radioactive inorganic phosphate.

PREVIOUSLY it was reported that exposure of rats to a cold environment (3± 1δ C) for both short periods (2, 3, 6 hours) and somewhat longer ones (2, 4, 8, 16 days) caused an increase in the incorporation of radioactive phosphorus (P32) into the inorganic phosphate, 20-minute hydrolyzable phosphorus, and total acid-soluble phosphorus of the adrenal gland, without concomitant change in phosphorus concentration. Evidence was presented for the view that this could be explained by an increase in the rate at which inorganic P32 passes from the extracellular to the cellular portion of the gland (Nicholls and Rossiter, 1955a). Furthermore, there is good evidence that the early (2 or 3 hours in the cold) response in the adrenal phosphorus metabolism is caused by the release of endogenous ACTH from the pituitary, and that the later response (8 days in the cold) is, in part at least, associated with an increase in the activity of the thyroid gland (Nicholls and Rossiter, 1955b).

Distribution and Incorporation of Radioactive Phosphorus in the Douglas-Fir Beetle12

The distribution of P32 in different parts of the body of Douglas- fir beetle, Dendroctonus pseudotsuffae Hopkins, and its incorporation into phosphorylated intermediates was studied. Most phosphate esters which are known to be intermediates of glycolysis were found to be present in the beetle.

The Incorporation of Radioactive Phosphorus into Influenza Virus

Summary Studies have been presented on the labelling of influenza virus with P32 during propagation in the allantoic cavity of chick embryos. The labelled virus has been purified routinely by 2 cycles of adsorption onto and elution from chicken red cells with intermittent dialysis against large volumes of phosphate buffered saline solution. The degree of radioactivity of the virus progeny could be improved by an increase in the dose of P32 used, by prolongation of the interval between injection of the isotope and infection, and by a reduction in the age of the embryos employed. The ratio between counts per minute and hemagglutinin units of the yields could be increased further by the use of deembryonated eggs instead of intact chick embryos. It has not been possible to separate the radioactivity from the virus particles by various biological, physical and chemical means. Chemical fractionation of labelled virus revealed most of the radioactivity in the lipid and nucleic acid fractions.

The incorporation of radioactive phosphorus in the influenza virus and its distribution in serologically active virus fractions.

1. When the D.S.P. strain of influenza virus A is grown in eggs into which 100 μc. of radioactive inorganic phosphate has been introduced the virus incorporates32P into its structure.2. Some 20–25% of the virus32P is found in the virus phospholipid; the remainder is combined with the virus protein and is probably present in the virus nucleic acid.3. When the virus is disintegrated by ether treatment with the liberation of separate red-cell agglutinating and complement-fixing ‘soluble antigen’ particles the non-lipid32P is found to be associated with the soluble antigen fraction and not with the haemagglutinin.4. It is suggested that the complement-fixing soluble antigen is a nucleoprotein while the haemagglutinin is a phosphorus-free protein.

Influenza Virus in Allantoic Sac Tissue Culture

Summary The use of allantoic sacs in suspended cell tissue cultures for the growth of influenza viruses has been investigated. Influenza A and B viruses grow readily in such cultures, with either Hanks-Simms' solution or Tyrode's solution as diluents. In the presence of the former solution, viral titers (influenza A) in tissue cultures reach a maximum slightly more slowly and decline more slowly than in Tyrode's solution. Step-wise curves of multiplication of virus are readily demonstrable without recourse to dilution or interference techniques. A complete cycle of multiplication of influenza A virus in this system requires approximately 18 hours, and increases the titer about 100-fold. Frequent changes of the nutrient fluid and the addition of embryo extracts do not increase the capacity of the tissue to support viral growth. The titer of hemagglutinin in such cultures is affected by the amount of tissue in the cultures and by the size of the inoculum. Quantitative study of the pentose and desozy-pentose nucleic acids of the cultures showed a progressive decrease in the former during the incubation of a tissue culture and insignificant alterations in the latter. Viral growth in such cultures may have increased the rate of decline of PNA more rapidly than in uninfected cultures, but had no consistent effect on DNA. Tyrode's and Hanks-Simms' solutions exerted similar effects on nucleic acid concentrations. The incorporation of radioactive phosphorus into nucleic acids of both types by the tissue cultures was rapid. There were no consistent effects on the pattern of uptake of phosphate by the tissue cultures as a consequence of viral multiplication in the cultures. The data indicate that multiplication of tissue cells was not prominent in these cultures, and that a net degradative effect predominated. Uptake of radioactive phosphorus offers a more reliable indication of sufficient viability of tissue cells to support viral growth in suspended cell cultures than do increases in nucleic acid concentration. In the presence of cortisone, both infected and uninfected cultures were characterized by the appearance of numerous cystic blebs of tissue, arising from the culture fragments of allantoic sac. Such outpouchings were less common in control cultures. No consistent effect of cortisone on the concentrations of pentose nucleic acid (PNA) or of desoxypentose nucleic acid (DNA) in the cultured tissues was demonstrable. The rate of incorporation of radioactive phosphate into PNA was slightly accelerated both in infected and uninfected cultures, but incorporation of phosphate into DNA was not significantly altered by the hormone. Cortisone did not affect viral multiplication significantly.

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

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

Phosphorus compounds in the cell. III. The incorporation of radioactive phosphorus into the ribonucleotide fraction of liver tissue.

Phosphorus compounds in the cell. III. The incorporation of radioactive phosphorus into the ribonucleotide fraction of liver tissue.