On the dependence of nuclear oxidative phosphorylation on glycolysis in isolated rat thymus nuclei

Résumé Les expériences présentées montrent qu'il est possible d'inhiber au maximum la glycolyse des noyaux isolés du thymus de rat, sans influencer la respiration et la synthèse d'ATP. Elles suggèrent ainsi que, dans ces noyaux, la phosphorylation oxydative ne dépend pas forcément de la glycolyse.     

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.     

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, tailor-made catalytic antibodies, and on the technique of in vitro mutagenesis are also described.     

Mesenchymal stem cells from preterm to term newborns undergo a significant switch from anaerobic glycolysis to the oxidative phosphorylation

We evaluated the energy metabolism of human mesenchymal stem cells (MSC) isolated from umbilical cord (UC) of preterm (< 37 weeks of gestational age) and term (≥ 37 weeks of gestational age) newborns, using MSC from adult bone marrow as control. A metabolic switch has been observed around the 34th week of gestational age from a prevalently anaerobic glycolysis to the oxidative phosphorylation. This metabolic change is associated with the organization of mitochondria reticulum: preterm MSCs presented a scarcely organized mitochondrial reticulum and low expression of proteins involved in the mitochondrial fission/fusion, compared to term MSCs. These changes seem governed by the expression of CLUH, a cytosolic messenger RNA-binding protein involved in the mitochondria biogenesis and distribution inside the cell; in fact, CLUH silencing in term MSC determined a metabolic fingerprint similar to that of preterm MSC. Our study discloses novel information on the production of energy and mitochondrial organization and function, during the passage from fetal to adult life, providing useful information for the management of preterm birth.     

Red blood cell glycolysis and potassium type in sheep

Summary Based on the observations made on human and dog red blood cells, it was recently proposed that the response of red cell glycolysis to variations in the levels of specific cations is an evolutionary adaptation in response to a specific cellular environment. We have now examined the effect of K⁺ and Na⁺ on the activity of pyruvate kinase (PK) in the red blood cells from 2 genetically different types of sheep high potassium (HK) and low potassium (LK). The results indicate that K⁺ stimulate glucose consumption and the activity of PK in both types of sheep. It thus appears that red cell PK from LK sheep does not fit into the concept of cellular environment and PK activity.This work was supported by grants from the National Health and Medical Research Council of Australia, the Clive and Vera Ramaciotti New South Wales Foundation and the Helena Rubenstein Foundation, Inc.     

The effect of bisphosphonates on glycolysis in cultured calvaria cells and their homogenate

Rat calvaria cells previously cultured for 7 days in the presence of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) or dichloromethylenebisphosphonate (Cl2MBP), showed a decrease in the glycolytic pathway. When glycolysis was analyzed under anaerobic conditions, this effect was not observed. The inhibition by the bisphosphonates occurred to a similar degree regardless of whether lactate production was measured in whole cells or in cell homogenates. Bisphosphonates added directly to the homogenate had no inhibitory effect. Thus, the effect is not a direct one and is unlikely to be due to a soluble mediator in the cytoplasm.     

Effect of hypoxia on glycolysis in isolated fetal rat heart]

Glycolysis was assessed in the isolated foetal Rat in hypoxia. Measurements were made of glucose uptake, lactate output, C14 glucose incorporation into glycogen and tissular levels of ATP, PCr, glycogen and lactate. Glycolysis was stimulated by hypoxia to a greater extent in the young foetal heart of 16.5 days post coitum than in the foetal heart at term. Thus high energy phosphates were maintained at a higher level in the younger heart. The results are discussed in relation to the high resistance to hypoxia of the foetal heart.     

Fat formation and glycolysis in tissue culture action of hydrocortisone

Zusammenfassung Fettsäuresynthese wird durch die Anwesenheit eines glykolytischen reduzierenden Systems gefördert. Die auffallende Tendenz normaler Gewebskulturzellen zur Fettanhäufung im Zytoplasma scheint mit dem charakteristisch hohen Fermentationsstoffwechsel der Gewebskulturen zusammenzuhängen. Die Steigerung der Fettbildung durch Hydrocortison in hoher Konzentration mag auch in Zusammenhang stehen mit dessen Eigenschaft, Spaltungsstoffwcchsel zu fördern.

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Reported in part at 8th Annual Meeting of Tissue Culture Association at the University of Baltimore, Md., April 17, 1957.

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Supported by U. S. Public Health Service grant.     

Electron spin resonance investigations on ferricytochromec compounds

Zusammenfassung Ferricytochromc aus Pferdeherz wurde bei einer Temperatur von 77°K mit der Methode der Elektronenspinresonanz untersucht. Aus den Elektronenspinresonanzspektren ist zu entnehmen, dass Ferricytochromc bei neutralem und alkalischem pH ein Lowspin-Komplex ist, bei stark saurem pH ist es dagegen ein Mischkomplex der High- und Low-spin-Form. Ferricytochrom-c-Fluorid ist ein reiner High-spin-Komplex; dagegen sind die Azid- und Zyanidkomplexe Low-spin-Komplexe.     

Hematological and serological investigations in heteroparabiosis

Zusammenfassung In der Heteroparabiose Maus-Hamster kommt eine parabiotische Intoxikation und hämolytische Anämie bei der Maus in 88% der Fälle zustande. Eine Immunisation der Maus mit Hamsterhauttransplantaten, die 10–12 Tage vor der Parabiose unternommen wird, kann die Erscheinung der Anämie bis auf 18% der Fälle herabsetzen. In Heteroparabiosen, die mit starker hämolytischer Anämie bei der Maus verliefen, wurde stets die Anwesenheit der Hämagglutinine und unvollständiger Antikörper im Serum des parabiotischen Hamsters festgestellt.     

ERR-spectroscopic changes on enzymatic depolymerization of spin-labelled amylose

Summary The ESR-spectra of nitroxyl-labelled amyloses (molecular weight 14,000) show anisotropic effects. Depolymerization with -amylase alters the spectra, and the rate of change is dependent on concentration of enzyme.     

Clinical investigations on the relation between macromolecular transport and chemical sensitization

Zusammenfassung Die Makromoleküle der am langsamsten transportierenden Individuen reagierten auf die Läppchenproben sämtlich negativ, ein positives Ergebnis wurde nur bei den schneller transportierenden Personen erhalten.     

Effect of methotrexate on glycolysis of leukemia L 1210 cells cultivated in vitro]

Methotrexate, at non lethal doses, alters the glycolysis of leukaemic L 1210 cells. Glucose uptake and lactate excretion are increased but lactate/glucose ratio remains constant. The activity of glycolytic enzymes in the cytoplasm is increased and the level of intracellular ATP is greatly enhanced.     

The modifying effects of oxytocin on stress-induced changes in post-mortem muscle glycolysis in pigs

Summary The effect of ante-mortem i.m. administration of oxytocin on post-mortem muscle metabolism in Pietrain pigs was examined. Treatment with oxytocin significantly retarded post-mortem glycolysis and stopped the production of pale, soft, exudative meat.