Rune Stjernholm

Carbohydrate metabolism in leukocytes: VIII. Metabolic activities of the macrophage

Abstract Macrophages from the guinea pig have been shown to have a high glucose utilization and a high aerobic lactate production. The extent of pentose cycle activity has been determined by two different methods and found to account for 3–6% of the total glucose utilization and between 20 and 50% of the oxygen uptake during phagocytosis. The remaining oxygen consumption may be due to Krebs cycle activity. Acetate is oxidized to about 1 μmole per hour per 10 8 cells. Further evidence for an active Krebs cycle was shown in experiments with labeled propionate. Labeling patterns found in lactate derived from propionate suggest that alternate mechanisms for propionate utilization are present in the macrophage.

METABOLISM OF METHYLMALONYL-COA AND THE ROLE OF BIOTIN AND B12 COENZYMES.

The role of methylmalonyl isomerase in metabolism was first elucidated by Flavin et aZ.l in 1955 during their study of propionate metabolism by animal tissue. For orientation we will first consider the role the isomerase reaction plays in this pathway and then its similar role in the formation of propionate by the propionic acid bacteria. Ochoa and coworkers have shown that propionate is metabolized in animal tissue by the following reactions:

Biocytin as a constituent of methylmalonyl-oxaloacetic transcarboxylase and propionyl CoA carboxylase of bacterial origin☆

Abstract Propionyl-CoA carboxylase containing tritium-labeled biotin has been partially purified from Mycobacterium smegmatis . After preliminary purification the purity of the enzyme can be followed by specific radioactivity. The propionyl-CoA carboxylase of bacterial origin differs from the same enzyme isolated from animal tissues. It has a broader pH range and a greater substrate affinity. Biocytin (ϵ- N -biotinyl- l -lysine) containing tritium-labeled biotin has been isolated and purified from preparations of oxaloacetic transcarboxylase of Propionibacterium shermanii and of propionyl-CoA carboxylase of M. smegmatis . 3

Carbohydrate metabolism in leucocytes. V. The metabolism of five-carbon substrates in polymorphonuclear leucocytes of rabbit.

Abstract The utilization in vitro of d -arabinose-1-C 14 and -5-C 14 , l -arabinose-1-C 14 , d -lyxose-1-C 14 , and ribitol-1-C 14 by polymorphonuclear leucocytes of rabbits has been investigated. Two indicators of metabolism, glycogen and lactic acid, were isolated and their C 14 distributions determined by degradation. On the basis of the tracer pattern it has been shown that these five-carbon substrates are metabolized via the transketolase-transaldolase sequence to fructose 6-phosphate followed by the Embden-Meyerhof pathway to lactic acid.

Interaction of Viruses with Human Lymphocytes

Publisher Summary This chapter discusses interaction of viruses with human lymphocytes. Lymphocytes have been shown to be the major cell type involved in the cell-mediated ImR, and their importance in the hosts defense against certain viral infections is illustrated by the severe infections produced by vaccinia and herpes viruses in patients with congenital thymic deficiency syndromes. Atypical lymphocytes appear in the circulation of infected individuals in many illnesses. In at least three, namely, infectious mononucleosis, Burkitts lymphoma, and infection with cytomegalovirus, a herpes-like virus has been associated with lymphocytes. A study has demonstrated blastoid transformation of normal lymphocytes after infecting leukocyte cultures with EB virus, the virus originally isolated from cultures of peripheral leukocytes taken from patients with Burkitts lymphoma. During the course of certain viral infections in both experimental animals and man, a transient depletion of circulating lymphocytes occurs. The chapter also highlights a study in which the lymphocytopenia was related to increased titers of virus in the blood and spleen.

Differential degradation of d- and l-glycerol-1-C14 by Aerobacter aerogenes☆

Abstract A degradation procedure has been developed, which allows determination of the isotope concentration in each of the carbon atoms of the glycerol molecule separately. The method involves bacterial fermentation of glycerol with Aerobacter aerogenes.

Metabolic deviations of polymorphonuclear leukocytes in rheumatoid arthritis

SummaryPolymorphonuclear leukocytes of normal individuals and of patients with rheumatoid arthritis were incubated in serum containing14C-labeled propionic acid. The overall metabolism was studied by determination of radioactivity in the respiratory CO2, lipids, proteins, amino acids and lactate. The metabolism of polymorphonuclear leukocytes of the arthritic group differed from that of normal individuals in the following respects. They converted less14C-propionic acid into metabolic products, particularly CO2 and protein. Leukocytes of normal subjects convert14C-propionate into aspartic acid and glutamic acid, while leukocytes of patients with rheumatoid arthritis also convert propionate into β-alanine.It appears that polymorphonuclear leukocytes of patients with rheumatoid arthritis and of normal individuals possess aKrebs cycle. Leukocytes of the arthritic group and of normal subjects show a similar14C-distribution pattern in the lactate when incubated 2-14C-propionate. It is concluded that the formation of lactic acid from 2-14C-propionate may proceed to a small extent by an alternate pathway (acrylyl-CoA). The identification of labeled β-alanine was found only in the arthritic group and may be unique for rheumatoid arthritis.ZusammenfassungPolymorphkernige Leukozyten von Normalpersonen und von Patienten mit primär chronischer Polyarthritis wurden in Serum inkubiert, das14C-markierte Propionsäure enthielt. Der Gesamtstoffwechsel wurde mittels der Bestimmung der Radioaktivität in respiratorischem CO2, Lipoiden, Proteinen, Aminosäuren und Laktat untersucht. Der Stoffwechsel von polymorphkernigen Leukozyten in der arthritischen Gruppe unterschied sich von dem der Normalpersonen in folgender Hinsicht: Sie setzten weniger14C-Propionsäure in Stoffwechselprodukte um, insbesondere CO2 und Protein. Leukozyten von Normalpersonen setzen14C-Propionsäure in Asparaginsäure und Glutaminsäure um, während die Leukozyten von Patienten mit primär chronischer Polyarthritis Propionsäure auch in β-Alanin umsetzen.Es scheint, daß die polymorphkernigen Leukozyten von Patienten mit primär chronischer Polyarthritis und von Normalpersonen einen Krebs-Zyklus besitzen. Leukozyten der arthritischen Gruppe und von Normalpersonen zeigen ein ähnliches Verteilungsschema von14C in Laktat nach Inkubation mit 2-14C-Propionat. Es wird daraus geschlossen, daß die Bildung von Milchsäure aus 2-14C-Propionat zu einem geringen Grade auf einem anderen Weg erfolgt (Acrylyl-CoA). Die Identifizierung von markiertem β-Alanin war nur in der arthritischen Gruppe möglich und kann für primär chronische Polyarthritis spezifisch sein.