The influence of the fungicide folcidin on the distribution and metabolism of32P in gherkin plants

High accumulation of³²P was observed in the leaves of intact gherkin plants 9 days after their roots had been treated with 0.005% suspension of the systemic fungicide Folcidin 50WP (cypendazole),i.e. 8 days after the roots had been exposed to labelled phosphate. Folcidin also influenced phosphorus metabolism in the plants. High biologic cytokinin-like activity of the fungicide was established when using a callus cytokinin bioassay.     

Membrane lipids composition and metabolism during early embryonic development. Phospholipid subcellular distribution and 32P labeling

Phospholipid composition and 32P metabolism were studied in oocytes and early developing embryos of the toad, Bufo arenarum, Hensel. The content and distribution of phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidic acid, sphingomyelin, phosphatidylserine, and diphosphatidylglycerol in embryos, whole oocytes, and the subcellular fractions of both were determined. Phosphatidylcholine and phosphatidylethanolamine were the major constituents of yolk platelet. Diphosphatidylglycerol was confined to the mitochondrial fraction, where it represented about 7% of the total phosphoacylglycerols. Relatively large amounts of sphingomyelin were found in microsomal and postmicrosomal supernatants. After in vivo labeling with 32P, the early development of individual phospholipids in subcellular fractions and in whole eggs was followed. The greatest uptake was found in mitochondrial and yolk platelet fractions. A steady increase in the amount of 32P present in phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol was seen in the whole embryo from oocyte to late gastrula stage and in all subcellular fractions. Phosphatidic acid exhibited a slight decrease in specific activity, except in the yolk platelet fraction. This high 32P incorporation would indicate a rapid and uneven polar headgroup turnover determined by phospholipid class and subcellular fraction. At the same time, the phospholipid content of the subcellular fractions studied remained unchanged during early embryogenesis. Moreover, 32P was actively incorporated into the individual phospholipids in the absence of measurable net synthesis.     

The effect of internal exposure to 90Sr on hematopoietic stem cells in CBA mice

After acute intake of 90Sr the changes of d-9 CFUs number in mice (CBA) bone marrow, spleen and peripheral blood were investigated. The obtained results indicated similar quantitative changes in bone marrow and spleen CFUs on exposure to the 90Sr when radiation doses did not cause the decrease in life-time (1.11 kBq/g). Sarcomogeneous doses of 90Sr (29.6 kBq/g) resulted in drastic changes of hemopoietic system: spleen haematopoiesis activation and suppression of bone marrow functions. On the first day after 90Sr injection (29.6 kBq/g) the increase in number of peripheral blood CFUs (circulating pool) was observed.     

The geterogenity of 137Cs and 90Sr distribution and dose loading on critical tissues of main seedling root

It is shown, that the roots of plants concentrate 137Cs and 90Sr from water solutions in different zones: 137Cs--mainly in a meristem zone, 90Sr--in a stretching zone. The similar character of radionuclide distribution was established regarding water and soil cultures. The real dose loading on critical tissues of main root have appeared to be much higher than it was expected from the assumption of uniform distribution of radionuclides in tissues.     

The effect of pesticides on the development in rats of osteosarcomas induced by 90Sr]

In experiments with rats the authors have assessed the development of remote effects of radiation (90Sr) combined with chronic exposure to chlorophos and lindane within a wide range of doses. It has been shown that chronically administered chlorophos and lindane have no carcinogenic and cocarcinogenic effects.     

The kinetics of 90Sr: genotypic determining

The genotypic component of the variability (intrafamily correlation) of body mass, mass of thigh-bones and concentration of 90Sr in bone tissue were evaluated in the progeny of the laboratory mice of CBA line which were in the conditions of normal or slow development of skeleton since their birthday and which got a single injection of 90Sr in the late ontogenesis. The evaluation was made with the control of the effects of sex and age membership of animals and also taking into account the conditions of their development. Significant intrafamily correlation of the concentration of 90Sr was revealed. It can be compared with the morphological signs, which are the evidence of existence of genotypic determinacy of the kinetics of 90Sr.     

Diffusion von45Ca,85Sr und32P in Hydroxylapatit

Zusammenfassung Es wurde der Transport von⁴⁵Ca,⁸⁵Sr und³²P in polykristallinen Sinterkörpern von synthetischem Hydroxylapatit im Temperaturbereich 1000 bis 1400 °C untersucht. Nach sorgfältiger Berücksichtigung von Korngrenzen-Diffusionseffekten ergaben sich für die Diffusion von⁴⁵Ca und⁸⁵Sr gleiche Werte für die Aktivierungsenthalpien und Frequenzfaktoren, und zwar beipH₂O<30 Torr:Q=3,50 ± 0,02 eV;D ₀=41 ± 5 cm²s^–1 und beipH₂O=230 Torr:Q=3,55 ± 0,02 eV;D ₀=20 ± 3 cm²s^–1 Die Abhängigkeit des Kationen-Diffusionskoeffizienten vom Wasserdampfpartialdruck ist vermutlich dadurch bedingt, daß im untersuchten Temperaturbereich feste Lösungen von Hydroxylapatit und Oxyapatit entstehen und Leerstellen im OH^–-Teilgitter den Kationentransport beschleunigen. Der³²P-Transport wurde nur bei 1360 °C undpH₂O < 30 Torr gemessen. Der Diffusionskoeffizient ist um einen Faktor 400 ± 50 kleiner als der entsprechende Diffusionskoeffizient der Kationen.Die Ergebnisse der Diffusionsuntersuchungen werden in Verbindung mit einer einfachen Modellvorstellung zum Retentionsmechanismus der Erdalkalien im Skelett diskutiert.

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Diffusion of⁴⁵Ca,⁸⁵Sr, and³²P in hydroxyapatite

Summary The transport of⁴⁵Ca,⁸⁵Sr, and³²P in polycrystalline sinter pellets of synthetic hydroxyapatite has been investigated in the temperature range 1000 to 1400 °C. After subtraction of activity transports by grain boundary diffusion processes, equal values of activation enthalpy and frequency factor were found for the lattice diffusion of⁴⁵Ca and⁸⁵Sr: atpH₂O<30 Torr:Q=3,50 ± 0,02 eV,D ₀=41 ± 5 cm²s^–1 and atpH₂O=230 Torr:Q=3,55 ± 0,02 eV,D ₀=20 ± 3 cm²s^–.The dependence of the cation diffusion coefficient on the partial vapour pressure is probably caused by formation of solid solutions of hydroxyapatite and oxyapatite where vacancies of the OH^– sublattice accelerate the cation transport. The diffusion of³²P was investigated only atT=1360 °C andpH₂O<30 Torr. The value obtained is smaller by a factor of 400 ± 50 then the cation diffusion coefficient.The results of the diffusion experiments are discussed in the light of a simple model for the retention mechanism of the alkaline earth metals in the skeleton.

     

The uptake and metabolism of [32P]pyrophosphate by mouse calvaria in vitro

In order to study the uptake and metabolism of PP(i) by bone, (32)PP(i) was added to the medium surrounding explanted mouse calvaria maintained in organ culture. Most of the PP(i) was hydrolysed during incubation, but there was a measurable entry of intact PP(i) into bone. When (32)P(i) was added to the medium, synthesis of PP(i) and organic phosphates from P(i) was observed in bone. There was no detectable passage of PP(i) from bone into the medium. These results are discussed in terms of two models of pyrophosphate hydrolysis and exchange. Some quantitative estimates about the fate of PP(i) in bone were made.     

P32 distribution in phosphorus fractions of phosphorus-sensitive and -tolerant soybeans

Summary P³² incorporation into various phosphorylated compounds of roots, stems, and leaves was studied with P-sensitive (Clark) and P-tolerant (L9) varieties of soybeans. With increasing P concentration in the pretreatment solution, more P³² was incorporated into the inorganic phosphate fraction, mainly in which form P seemed to be transported from roots to leaves. P³² percentage of inorganic phosphate also showed a continuous decrease with absorption time. The rate of phosphorylation, as manifested by the ratio of P³² percentage or specific activities of the organic acid-soluble P to that of inorganic-P, was higher with the P-tolerant variety than with the P-sensitive one. The rate of RNA synthesis also seemed to be higher with the tolerant variety. Paper No. 7082, Scientific Journal Series, Minnesota Agricultural Experiment Station.