Neutrophils biosynthesize leukotoxin, 9, 10-epoxy-12-octadecenoate.

An epoxy derivative of linoleate, 9,10-epoxy-12-octadecenoate, was demonstrated to be biosynthesized by neutrophils from various sources such as canine and human blood, and guinea-pig peritonea. It was nominated as leukotoxin from its 'toxic' activity onto mitochondrial respiration. From the reaction mixture of leukocytes with linoleate, an isomer of leukotoxin, 12,13-epoxy-9-octadecenoate, and a 'non-toxic' hydroxy derivative of linoleate, 9-hydroxy-12-octadecenoate, were detected. Such a cascade reaction of linoleate by leukocytes was discussed. Biosynthesis of leukotoxin by neutrophils was substantially enhanced by the presence of calcium ion and calcium-ionophore, A23187. Neutrophils contained leukotoxin, ca. 7 f moles/cell, which was extractable by 60% ethanol, but little of the isomer.

Biosynthesis of 16 alpha, 17 alpha-epoxy-oestratrienol in rat liver microsomes.

After incubation of 1,3,5(10),16-oestratetraenol, a 16-dehydrosteroid, with rat liver microsomes, 16 alpha, 17 alpha-epoxy-oestratrienol was isolated as metabolite. The compound was detected by the use of mass fragmentography after purification of the incubation extract by thin-layer chromatography. Since the epoxide is rapidly hydrolysed by a hepatic epoxide hydratase, only very small concentrations of this metabolite were present in the incubation extract. When styrene oxide was added to the incubation mixture as inhibitor of the epoxide hydratase, the yield of the steroid epoxide increased considerably. Final identification of the oestrogen epoxide was performed by recording mass spectra and by comparison with authentic reference material.

[Molecular aspects of carcinogenesis (author's transl)]. / Molekulare Aspekte der Karzinogenese.

The mechanism of carcinogenesis is not yet understood. There is increasing evidence justifying the assumption that an unifying concept of carcinogenesis should be possible at the molecular level. New insights into the molecular mechanism of carcinogenesis were mainly obtained in studies on both chemical and viral carcinogenesis. In the present paper, selected results of these studies are reviewed. It is concluded that the interaction of different carcinogenic agents with the cellular DNA results in alterations of DNA. Only some of these alterations, however, seem to be relevant to carcinogenesis. Alterations of DNA can be caused by reaction of electrophilic agents with DNA constituents, by increased infidelity of DNA replication, by integration of viral genomes or by recombination events involving integrated proviruses.

Accumulation of 1-trans-2,3-epoxysuccinic acid and succinic acid by Paecilomyces varioti.

The biogenic acids 1-trans-2,3-epoxysuccinic acid and succinic acid accumulate in decationized refiner's blackstrap molasses shake cultures of Paecilomyces varioti Bainier. The maximum accumulation of 1-trans-2,3-epoxysuccinic acid occurred in a medium which contained Cu2+ and Fe3+ at concentrations of 1.0 and 2.0 mM, respectively. The maximum accumulation of succinic acid occurred in a culture medium which contained Cu2+ at a concentration of 0.01 mM and Fe3+ at a concentration of 1.0 mM.

PR toxin production in different Penicillium roqueforti strains.

Different Penicillium roqueforti strains from the American Type Culture Collection were tested for the production of PR toxin. All four strains were able to produce the toxin on semisynthetic medium at 24 degrees C after certain periods of incubation. The yields were correlated with the pH of the medium. Timing of the harvest influenced both the yield and purification of the toxin.