An overview of siderophores for iron acquisition in microorganisms living in the extreme

Abstract

Siderophores are iron-chelating molecules produced by microbes when intracellular iron concentrations are low. Low iron triggers a cascade of gene activation, allowing the cell to survive due to the synthesis of important proteins involved in siderophore synthesis and transport. Generally, siderophores are classified by their functional groups as catecholates, hydroxamates and hydroxycarboxylates. Although other chemical structural modifications and functional groups can be found. The functional groups participate in the iron-chelating process when the ferri-siderophore complex is formed. Classified as acidophiles, alkaliphiles, halophiles, thermophiles, psychrophiles, piezophiles, extremophiles have particular iron requirements depending on the environmental conditions in where they grow. Most of the work done in siderophore production by extremophiles is based in siderophore concentration and/or genomic studies determining the presence of siderophore synthesis and transport genes. Siderophores produced by extremophiles are not well known and more work needs to be done to elucidate chemical structures and their role in microorganism survival and metal cycling in extreme environments.

Metal-ion-induced expression of gene fragments from subseafloor micro-organisms in the Kumano forearc basin, Nankai Trough

“…Siderophores are produced by micro‐organisms in a variety of environments (De Serrano et al . ) and bind gallium (Gascoyne et al . ; Chitambar ); however, available sequence data suggests only that the potential promoter region leads to gene induction in the presence of Ga 3+ and Fe 3+ , and the inserted sequence in the Ga‐4 clone was too short to include information on the downstream gene.…”

The “Green” FMOs: Diversity, Functionality and Application of Plant Flavoproteins

“…These hydroxamates are precursors in the biosynthesis of siderophores; low molecular-weight iron chelators, which are secreted to then be imported in their iron-loaded form [37]. Iron is involved in several pivotal cellular processes, such as oxygen transport, respiration, nitrogen fixation, photosynthesis, and synthesis of DNA, fatty acids, and amino acids [38,39].…”

Siderophore Production by Rhizosphere Biological Control Bacteria Brevibacillus brevis GZDF3 of Pinellia ternata and Its Antifungal Effects on Candida albicans

“…The siderophore production was determined by CAS liquid test. The cell growth and siderophore production were measured as a function of fermentation time at 0, 6,12,18,24,30,36,42,48,54, and 60 h. The pH was adjusted to 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, and 10.0, respectively. Fermentation temperature was set from 23°C to 37°C.…”