Two ferric ion-binding compounds, designated staphyloferrin A and B, were detected in the culture filtrates of staphylococci grown under iron-deficient conditions. Staphyloferrin A was isolated from cultures of Staphylococcus hyicus DSM 20459. The structural elucidation of this highly hydrophilic, acid-labile compound revealed a novel siderophore, N 2 , N 5 -di-(l-oxo-3-hydroxy-3,4-dicarboxybutyl)-~-ornithine, which consists of one ornithine and two citric acid residues linked by two amide bonds. The two citric acid components of staphyloferrin A provide two tridentate pendant ligands, comprising of a /I-hydroxy, P-carboxy-substituted carboxylic acid derivative, for octahedral metal chelation. The CD spectrum of the staphyloferrin A ferric complex indicates a predominant A configuration about the ferric ion center. The uptake of ferric staphyloferrin A by S. hyicus obeys MichaelisMenten kinetics ( K , = 0.246 pM; v,,, = 82 pmol . mg-. min-I), indicating active transport of this siderophore.The staphyloferrin A transport system is different from that of the ferrioxamines as shown by an antagonism test. Production of staphyloferrin A is strongly iron-dependent and is stimulated by supplementation of the medium with either D-or L-ornithine. ~~-[S-'~C]ornithine was incorporated into staphyloferrin A, demonstrating that ornithine is an intermediate in staphyloferrin A biosynthesis.Iron, the fourth most abundant element of the earths crust, is required by all aerobic microorganisms and plays an important role in membrane-bound electron-transport chains as well as in cytoplasmic redox enzymes. In an aerobic environment iron is present in the Fe(II1) oxidized form, which polymerizes into insoluble ferric oxyhydroxides under physiological conditions [l, 21. In mammals, iron is bound to proteins such as lactoferrin and transferrin, and is therefore inaccessible, by direct means, to microorganisms [3]. Thus, microorganisms have developed different strategies to provide themselves with iron. The most common and well-investigated strategy is the high-affinity Fe( 111) uptake via siderophores. During iron deficiency, microorganisms excrete low-molecular-mass iron(II1)-chelating compounds (siderophores) in their iron-free form. After ferric ion chelation, the complexes are actively taken up by specific transport systems [4]. Several hundred siderophores from prokaryotes and eukaryotes are now known, which can structurally be assigned to the major classes of hydroxamate-and catecholate-type siderophores.

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A highly hydrophilic compound was isolated from low iron culture broth of Staphylococcus hyicus DSM 20459 which exhibits siderophore activity to the producer and 37 other staphylococci. The previously unknown metabolite was designated staphyloferrin A and constists of two molecules of citric acid, each linked to d‐ornitine by an amide bond. Using an iron‐pair HPLC‐system we detected staphyloferrin A and a second iron regulated compound (staphyloferrin B) in the culture fluid of several Staphylococcus strains. We found no evidence that staphylococci synthesize catecholor hydroxamate‐type siderophores.

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A strain that produces new lipopeptide antibiotics is a new species of the genus Actinoplanes for which we propose the name Actinoplanes friuliensis (type strain: HAG 010964). The strain is an actinoplanete actinomycete having cell wall II composition and forming sporangia. Comparisons with Actinoplanes spp. which have similarities with our isolate, including fatty acid analysis, showed that the isolate belongs to a new species. Taxonomic studies and fermentation are presented.