Reaction step requiring protein synthesis in DNA synthesis in sea urchin embryos

Summary In the acid-soluble fraction extracted from embryos treated with cycloheximide, thymidine triphosphate was largely accumulated and DNA polymerase activity decreased, while both activities of thymidine kinase and thymidylate kinase remained unchanged.     

New developments in enzymatic peptide synthesis

This review article describes new enzymatic methods developed for the efficient and irreversible synthesis of peptides based on native and modified proteases, and for the synthesis of polypeptides containing D- and/or unnatural amino acids. Potential opportunities for future developments in the field based on new enzymes, tailormade catalytic antibodies, and on the technique of in vitro mutagenesis are also described.     

Catalase synthesis and destruction in starvation

Zusammenfassung In der Leber hungernder Ratten verliefen Auf- und Abbaugeschwindigkeit der Katalase während der ersten 5 Tage im wesentlichen wie bei den Kontrolltieren. Durch die Verkleinerung der Leber wurde bei den Hungertieren total weniger Katalase in derselben Zeitspanne synthetisiert. Nach 5 Tagen fiel die Geschwindigkeit der Katalase-Synthese pro g Leber allmählich bis zum Tod der Tiere ab.

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Presented in part at the Fifth International Congress on Nutrition, Washington (D.C.) September 1960.     

Endogenous inhibitor of ecdysone synthesis in crabs

Summary Attempts to isolate the molt-inhibiting hormone (MIH) of crustaceans from crab eyestalks (ES) resulted in the characterization of xanthurenic acid as an inhibitor of ecdysone biosynthesis in the cultured Y-organ-complex (YOC) homogenate. It was also found that 3-hydroxyl-l-kynurenine present in the ES is transformed into xanthurenic acid in the YOC and body fluid. Its mode of inhibitory action in ecdysone biosynthesis is probably inactivation of cytochrome P-450.Acknowledgments. We thank Prof. M. Oka (Nagasaki University) and Dr J. Cappuzo (Oceanographic Inst.) for information on Y-organ and molting stages, Dr J. Termini and Mr J. Cesarelli (Columbia University) for organ excision of blue crabs and experiments in the early stage of this study, the Japan Sea Farming Association for aqua culture of crabs, Prof. Y. Umebachi (Kanazawa University) for a gift of 3-OH-l-Kyn, and Mr J. Rudloe (Gulf Specimen Co.) for collection and shipping of some selected crabs. This study was partially supported by NIH grant AI 10 187 (to K. N., at Columbia University).     

Cholesterol synthesis in freshly isolated human leukocytes

Summary Cholesterol synthesis has been studied in human leukocytes shortly after the isolation from healthy subjects. Not delipidated human serum reduced the cholesterol synthesis when added to the incubation medium. A similar effect was obtained when the leukocytes were incubated in the presence of physiological concentrations of low density lipoproteins.     

Albumin synthesis in regenerating rat liver cells

Riassunto Gli autori hanno studiatoin vitro il problema della sintesi dell'albumina in sezioni di fegato normale e rigenerante di ratto. La quantità di albumina prodotta durante l'incubazione non presenta notevoli variazioni nelle due situazioni studiate. Al contrario l'incorporazione di glicina marcata nella albumina del fegato rigenerante risulta nettamente aumentata rispetto a quella del fegato normale. Tale comportamento viene interpretato come espressione di un ricambio albuminico più elevato nel fegato rigenerante che nel normale.

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This investigation was aided by a grant from C.N.R., Roma, and was made during a tenure by one of us (G. G.) of a Scholarship from C.N.R., Roma.     

Noradrenaline synthesis in human fetal heart.

The capacity of noradrenaline synthesis was investigated in 6 isolated human fetal hearts (13-23 gestational week). The mean rate of transforming perfused labelled tyrosine to noradrenaline in atrial, ventricular, and mediastinal tissue was 0.175, 0.168, and 0.108 mug/g tissue/h, respectively.     

Ethanol and liver protein synthesis in vivo

Summary Ethanol was administered i.p. to adult roosters during hormonally induced vitellogenin synthesis. At moderate doses, ethanol had no influence on the synthesis of vitellogenin nor did it cause alterations in the size distribution of liver polyribosomes.This was supported in part by a grant from the Foundation for Alcohol Studies, Finland.     

Stereoselectivity in peptide synthesis under simple conditions

Zusammenfassung Die Umsetzung vond,l-Leucin mit verschiedenenl-Aminosäuren und Dicyanamid als Kondensationsmittel zu Oligopeptiden verläuft nicht stereoselektiv. Die Bedeutung dieser Beobachtung in bezug auf den Ursprung des Lebens wird diskutiert.     

Thyroid hormone synthesis during hypothermia in rats

Zusammenfassung Tiefe und oberflächliche Hypothermie an Ratten reduziert die Radiojodfixation der Schilddrüse. Markierte Jodtyrosine werden dedektiert, während Jodtyronine fehlen.     

Endogenous inhibitor of ecdysone synthesis in crabs

Attempts to isolate the molt-inhibiting hormone (MIH) of crustaceans from crab eyestalks (ES) resulted in the characterization of xanthurenic acid as an inhibitor of ecdysone biosynthesis in the cultured Y-organ-complex (YOC) homogenate. It was also found that 3-hydroxy-L-kynurenine present in the ES is transformed into xanthurenic acid in the YOC and body fluid. Its mode of inhibitory action in ecdysone biosynthesis is probably inactivation of cytochrome P-450.