The coenzyme A-synthesizing protein complex (CoA-SPC) is a multienzyme complex of Saccharomyces cerevisiae (Bakers' yeast), which has a molecular weight in excess of 200,000 as determined by Sephadex G-200 column chromatography. This multienzyme complex, which is insoluble in the crude yeast cell lysate, has been purified 229-fold. A cellular component of the yeast cell lysate, referred to as t-Factor, with a molecular weight of 400-1000 and chloride ion are involved in the solubilization of CoA-SPC. The CoA-SPC requires L-cysteine, D-pantothenic acid and ATP as substrates. The terminal CoA-SPC-bound intermediate is dephospho-CoA, which is subsequently phosphorylated and released from the complex as CoA. The sequence of reactions for the synthesis of CoA by the CoA-SPC differs significantly from those previously proposed for other systems. It could be that the reaction sequence is unique for the yeast cell.
Summary.-A transplantable reticulum-cell sarcoma induced by Rauscher virus (RV) in (C57BL/6 x DBA/2)F1 (BDF1) mice was grown in tissue culture. Four separate cell lines were established, all of which grew predominantly in suspension. The doubling time of the cells from these cultures ranged from 17 to 32 h. Each culture continued to replicate RV, as indicated by the infectivity in newborn mice of all fluids tested up to the 75th passage. Since the morphological appearance of the cells in vitro was consistent with that of proerythroblasts, all cultures were tested for their ability to differentiate along the erythrocytic line under the influence of dimethylsulphoxide (DMSO). One of the cultures produced small quantities of haemoglobin independently of DMSO. Another was shown to produce haemoglobin, as well as to take up 59Fe and incorporate it into haem, only in the presence of DMSO. The 2 remaining cultures failed to produce haemoglobin, either spontaneously or in the presence of DMSO. Cells from each of the RV-induced cultures, when inoculated back into BDF1 mice, induced typical reticulum-cell sarcomas, without in vivo evidence of erythroid differentiation. In contrast, 2 morphologically identical but non-infectious cell lines derived from Friend virus-induced reticulumcell sarcomas did not show erythroid differentiation in vivo or in vitro, either in the absence or presence of DMSO.
Abdel-Wahab et al.: Study of the Dependence of Photosynthetic Yields on the Water and Mineral Supply, Part 3 Aus der Aufnahme des Nitratstickstoffs aus dem Dungemittel folgt, daB in der ersten Vegetationsperiode der Ausnutzungskoeffizient von etwa 25% in der Variante NPK auf Werte von 36 bis 66% ansteigt, wenn man Stimulationsdosen von Phenolderivaten einfuhrt. Wendet man Inhibitionsdosen an, so sinkt dies:r Koeffizient bis auf 12% (0,1 mgDNP), . 3 % (1 mg DNP) oder sogar unter 1 % (1 mg DNOK). 2 ) Bis zur Reife wird der aus dem Dungemittel stammende Nitratstickstoff bei der Variante NPK (ohne Zufugung von Phenolderivaten) in einem Mengenverhaltnis von etwa 40% aufgenommen. Bei den Varianten mit Zufugung von Phenolderivaten hat der Ausnutzungskoeffizient Werte zwischen 31 und 42%. Ausnahmen stellen die Dosen von 1 mg/GefaB DNP (tjso; = 2%) und DNOK 07 NO ,-< 1 %) dar, wobei die Aufnahme des Nitratstickstoffs bis zuletzt stark gehemmt bleibt. *) Der letztgenannte Wert ist unwahrscheinlich klein. Der Versuch soil im folgenden Jahr wiederholt werden.Bei der Reife ergibt sich demnach im Durchschnitt folgende Bilanz der Verwendung des Nitratstickstoffs: Etwa 40% werden von der Pflanze aufgenommen, unter 1 % verbleibt in einer von der Pflanze aufnehmbaren Form fur die nachste Pfianzenkultur im Boden (Bestimmung, die mit Hilfe der Senfkultur gemacht wurde), der Rest (etwa 60%) wird wahrend der Vegetationsperiode des Hafers in nichtaufnehmbare Formen umgewandelt oder geht durch Verfluchtigung verloren.(The Middle Eastern Regional Radioisotope Centre for Arab Countries in Co-operation with the International Atomic Energy Agency, Dokki, Cairo/U.A.R.)
1.P 32 and C 14 have been used together to identify and trace the photosyiithates ofZea mays during the seedling stage. By this double labelling technique and single labelling with C li O2 and HiP 32 O^., carbohydrates, amino acids, andphosphoproteins were identified on paper chromatograms. Tables and figures summarise the results obtained under different mineral deficiency. These results indicate the effects of the absence ofP, Mg, K, N, Ca, and trace elements on both respiration and photosynthesis.
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