X-linked Alport syndrome is a hereditary glomerulonephritis in which progressive loss of kidney function is often accompanied by progressive loss of hearing. Ultrastructural defects in glomerular basement membranes (GBM) of Alport syndrome patients implicate an altered structural protein as the cause of nephritis. The product of COL4A5, the alpha 5(IV) collagen chain, is a specific component of GBM within the kidney, and the gene maps to the same X chromosomal region as does Alport syndrome. Three structural aberrations were found in COL4A5, in intragenic deletion, a Pst I site variant, and an uncharacterized abnormality, which appear to cause nephritis and deafness, with allele-specific severity, in three Alport syndrome kindreds in Utah.

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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