H. Bickel

Über eisenhaltige Wachstumsfaktoren, die Sideramine, und ihre Antagonisten, die eisenhaltigen Antibiotika Sideromycine

A new group of iron-containing metabolites, with growth stimulating properties for a number of microorganisms, has been isolated from streptomycetes and namedferrioxamines. It is proposed to include them, together with some known substances, like ferrichrome, coprogen and the terregens factor, which either contain or bind iron, in a new class of growth factors, thesideramines. The biological property of the sideramines is counteracted by iron-containing antibiotics from streptomycetes, thesideromycins. They comprise, besides known products like grisein and albomycin, two new groups of antibiotics, among them the highly potentferrimycins.

Zur Kenntnis von Levorin A und Candicidin

A sample of Russian provenance of the antifungal antibiotic levorin A, containing 30,000 microbiological units of activity/mg, was shown to consist of several components. Three components, designated levorin A1, A2 and A3, were isolated and shown to be distinguishable by their partition coefficients in the system chloroform-methanol-borate buffer pH 8.4 (2:2:1). An enriched sample of the antifungal antibiotic candicidin, prepared from a commercial preparation of American provenance, showed a very similar pattern of distribution as levorin A did in 600 transfers. Levorin A2, the main component of the levorin A sample, was not distinguishable within the error limits of the applied tests, from the main component of the enriched candicidin sample.

A new group of rifamycin derivatives displaying activity against rifampicin-resistant mutants ofStaphylococcus aureus

Unter einer grossen Anzahl semi-synthetischer Rifamycinderivate wurde eine Gruppe strukturell verwandter Verbindungen gefunden, die neben ihrer hohen Wirksamkeit (MIC ∼ 0,002-0,01 Μg/ml) gegenüber rifampicinsensiblen, grampositiven Keimen in vitro auch eine gute Wirkung (MIC ∼ 1–10 (Μg/ml) gegenüber rifampicinresistenten, grampositiven Keimen aufweisen. Die Resistenzrate grampositiver rifampicinresistenter und -sensibler Keime ist bezüglich dieser Verbindungen mindestens 100mal kleiner als bei Rifampicin. Die Wirkung gegenüber resistenten Keimen scheint nicht auf einer Beeinflussung der DNA-abhängigen RNA-Polymerase zu beruhen. Eine Struktur-Wirkungs-Beziehung wird angegeben.