In contrast to lactoferrin, desferrioxamine and deferiprone, DIBI provided almost complete inhibition of the growth of both C. albicans and C. vini over a 4-day incubation period. Candida albicans has been reported to use iron from the ferriproteins haemin, haemoglobin and myoglobin (Han, 2005), and to acquire iron from transferrin (Knight et al., 2005). However, the slight increase of the maximum specific

growth yields observed in the presence of some chelators in this study was not significant enough to support chelator-assisted iron acquisition. In a long-term study with reduced, subinhibitory concentrations (0.17 g L−1), DIBI did allow delayed and gradual growth of both yeasts, which was comparable to inhibition by EDTA for C. albicans and to BPS in C. vini. In contrast to EDTA and BPS, which are known to readily chelate other transition metals (Ueno et al., 1992), DIBI was shown to be iron-selective and its inhibitory activity was shown to be Dasatinib supplier Fe reversible. Accordingly, DIBI appeared to be a more potent iron scavenger than any of the other clinically

relevant chelators examined. This work presents the first evidence of the iron requirements of C. vini, a nonpathogenic food spoilage organism, and the inhibition of www.selleckchem.com/products/PF-2341066.html C. vini and the opportunistic pathogen C. albicans by several strong chelators. The differences observed with respect to the ability of C. vini and C. albicans to grow under iron-restricted conditions were consistent with the respective environmental niches and pathogenicity. Protein kinase N1 The present work provides a foundation for future studies that may investigate the possible synergistic effects of iron withdrawal in combination with

antifungal preservative addition. The authors thank Chelation Partners for supplying the FEC-1 chelating adsorbent and the DIBI chelator. “
“Sinorhizobium meliloti associates with Medicago and Melilotus species to develop nitrogen-fixing symbioses. The agricultural relevance of these associations, the worldwide distribution of acid soils, and the remarkable acid sensitivity of the microsymbiont have all stimulated research on the responses of the symbionts to acid environments. We show here that an adaptive acid-tolerance response (ATR) can be induced in S. meliloti, as shown previously for Sinorhizobium medicae, when the bacteria are grown in batch cultures at the slightly acid pH of 6.1. In marked contrast, no increased tolerance to hydrogen ions is obtained if rhizobia are grown in a chemostat under continuous cultivation at the same pH. The adaptive ATR appears as a complex process triggered by an increased hydrogen-ion concentration, but operative only if other – as yet unknown – concomitant factors that depend on the culture conditions are present (although not provided under continuous cultivation). Although the stability of the ATR and its influence on acid tolerance has been characterized in rhizobia, no data have been available on the effect of the adapted state on symbiosis.