In vitro incorporation of 2′-deoxyadenosine and 3′-deoxyadenosine into yeast tRNAPhe using tRNA nucleotidyl transferase,and properties of tRNAPhe-C-C-2′dA and tRNAPhe-C-C-3′dA

2′-Deoxyadenosine and 3′-deoxyadenosine (cordycepin) can be incorporated into the 3′-terminal position of tRNA^Phe by tRNA nucleotidyl transferase. tRNA^Phe-C-C-2′dA and tRNA^Phe-C-C-3′dA, missing the cis-diol group at the 3′-terminal end are resistant to periodate oxidation and are not able to form borate complexes. In aminoacylation experiments only the tRNA^Phe-C-C-3′dA proved to be chargeable.     

Selective Utilization of Pyrimidine Deoxyribonucleosides for Deoxyribonucleic Acid Synthesis in Pneumococcus

When pyrimidine deoxyribonucleosides are supplied to growing cultures of Diplococcus pneumoniae, they are selectively used for incorporation into deoxyribonucleic acid (DNA). Differently labeled molecules of deoxyuridine, thymidine, and deoxycytidine were used to study the precursor pathways of this organism. Each of these preformed pyrimidine deoxynucleosides is incorporated intact (i.e., without cleavage of the glycosidic bond) and is predominantly recoverable as DNA thymidine. During the utilization of deoxycytidine and deoxyuridine by pneumococci, large proportions of the available precursor are converted to free thymidine, which is secreted back into the growth medium. The biochemical pathways for selective incorporation into DNA and the regulation of concentrations of intracellular thymidine compounds by excretion of free thymidine are discussed.     

Beiträge zur funktionellen Morphologie der Neurohypophyse

Zusammenfassung Beidseitige Adrenalektomie und Hypophysektomie führen bei der Ratte zu gleichartigen histologischen Veränderungen in der Zona externa infundibuli. In beiden Fällen treten in der normalerweise weitgehend goniorinegativen Zona externa infundibuli große Mengen gomoripositiver Granula auf. Sie scheinen Fasern anzugehören, die senkrecht zur Längsachse des Infundibulum verlaufen.Die Befunde werden als weiterer Hinweis dafür betrachtet, daß die gomoripositiven Substanzen der Zona externa infundibuli eine Bedeutung für die Steuerung der Nebennierenrindenfunktion haben.

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Studies on the functional morphology of the neurohypophysisII. Comparison of histological changes in the median eminence of the rat after bilateral adrenalectomy and hypophysectomy

Summary Bilateral adrenalectomy and hypophysectomy in the rat produce similar histological changes in the outer layer of the median eminence. In both cases, abundant gomoripositive granules are observed in the outer layer, which normally reacts gomorinegative. The gomoripositive granules seem to belong to fibres running vertically through the infundibulum.These findings are regarded as a further indication, that the gomoripositive substances of the outer layer of the median eminence play a significant role in controlling adrenocortical function.

     

Incomplete bacteriophage-like particles in ultraviolet-irradiated haemophilus

Incomplete phagelike particles were found in competent and incompetent cells of Haemophilus influenzae Rd (transformable) lysed after exposure to ultraviolet radiation.     

Energetics of the budding cycle of Saccharomyces cerevisiae during glucose limited aerobic growth

Summary A method for the estimation of the yield on energy (Y _ATP) and of the efficiency of oxidative phosphorylation, in vivo (P/O ratio) is described, which is based on the measurement of effective gas exchange values ( and ) and of the yield coefficient Y of continuously growing populations of baker's yeast which vary in the degree of fermentation and respiration. For Y _ATP a value of 12.0±0.5 and for P/O ratio one of 1.1±0.05 was found and seems to be independent of the type of glucose catabolism (under glucose limitation).The gas exchange of populations of Saccharomyces cerevisiae synchronized at different growth rates was determined. The specific oxygen uptake and carbon dioxide formation rate, Q _{O 2}, and Q _{CO 2}, are shown to depend on the state of the cells in the budding cycle. Increase in gas metabolism and therefore increased energy generation coincides with the initiation of budding. The longer the generation time g the more expressed are these oscillations of energy formation over the budding cycle. The relationship between the course of energy generation and energy storage and the sequence of budding and single cell phase over the division cycle is discussed.     

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