Rhodotorulic Acid from Species of Leucosporidium, Rhodosporidium, Rhodotorula, Sporidiobolus , and Sporobolomyces , and a New Alanine-Containing Ferrichrome from Cryptococcus melibiosum

Abstract

An examination of 142 strains within 19 genera of yeasts and yeastlike organisms for formation of hydroxamic acids in low-iron culture showed production of hydroxamates by two unclassified strains and by 52 strains among the genera Aessosporon (3 of 3 strains), Cryptococcus (1 of 43), Leucosporidium (3 of 11), Rhodosporidium (4 of 4), Rhodotorula (27 of 39), Sporidiobolus (2 of 2), and Sporobolomyces (12 of 13). Crystalline rhodotorulic acid was isolated in amounts sufficient to account for most or all of the measured hydroxamate in culture supernatants of 16 strains representative of the five last-mentioned hydroxamate-producing genera. A new alanine-containing ferrichrome was isolated from one strain of Cryptococcus melibiosum. Rhodotorulic acid was a major metabolic product of many of the positive strains when grown in low-iron media, and iron was shown to repress its synthesis and excretion into the culture medium. The taxonomic significance of production of hydroxamic acids is described in connection with the position of these yeast species in the subclass Heterobasidiomycetidae. Numerous nonporphyrin iron-chelating natural products have been isolated from low-iron cultures of bacteria, actinomycetes, and fungi [16, 26-28; J. B. Neilands Microbial iron transport compounds. In G. Eichhorn (ed.), Inorganic Biochemistry, Elsevier Publishing Co., Amsterdam, the Netherlands, in press]. Most of these compounds contain three secondary hydroxamic acid groups; collectively, they are termed siderochromes. Those members which are antibiotics (i.e., albomycin) and those with growthfactor or antibiotic-antagonist activities (i.e., ferrichrome), or both, are called sideromycins and sideramines, respectively (3). Sideramines MATERIALS AND METHODS Cultures were maintained on 4% malt extract agar (Difco) or on 5 to 10% Dry Diamalt 20 (Fleischmann) with 2% agar. Growth was generally much more vigorous on the latter medium. Most of the strains were obtained from the yeast collection of the Depart

Haem iron‐transport system in enterohaemorrhagic Escherichia coli O157:H7

“…EDL933, however, did not utilize or produce aerobactin. Bioassays and the ferric perchlorate assay for hydroxamate siderophores (Atkin et al, 1970) were negative. We therefore screened for the presence of other iron-transport systems which might function within the host.…”

“…Chemical assays were used to detect synthesis of siderophores by E. coli O157:H7 strain EDL933. The strain was grown for two passages in Tris-buffered M9 medium (Sambrook et al, 1989), and the supernatant was tested using the Arnow assay for catechol siderophores (Arnow, 1937) and the ferric perchlorate assay for hydroxamates (Atkin et al, 1970). Bioassays to detect production of siderophores, and to assess the ability of EDL933 to use siderophores or other iron complexes for growth in low-iron medium were performed as follows.…”

A new approach to isolating siderophore-producing actinobacteria

“…Siderophore production was confirmed using the chrome azurol sulphate (CAS) assay (Renshaw et al 2003). The presence of a catecholic compound was further verified by Arnow's assay (Arnow 1937); hydroxamate producers were identified using the colorimetric assay of Atkin et al (1970).…”

Cadmium‐induced changes in the production of siderophores by a plant growth promoting strain of Pseudomonas fulva

“…After 1 h of stirring, absorbance was measured at λ = 520 nm using a UV-Vis Spectrophotometer (NanoDrop 2000). The results were analyzed based on a standard curve for deferoxamine methanesulfonate salt (Desferal, Sigma-Aldrich, Germany) ranging from 5 to 250 mM [28,29] and presented as μg ml −1 . 6 ] dissolved in 0.1 M HCl) were stirred.…”