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Role of Microorganisms in Improving Quality of Medicinal Aromatic Plants (MAPs)
Published in Gustavo Molina, Zeba Usmani, Minaxi Sharma, Abdelaziz Yasri, Vijai Kumar Gupta, Microbes in Agri-Forestry Biotechnology, 2023
Nirali Desai, Helly Shah, Manan Shah
Siderophores are iron-chelating low molecular weight compounds produced by some microorganisms and plant species. Siderophores promote plant growth in iron-deficient environments by solubilizing iron in ferric complexes obtained from the minerals. Bacteria like Sphingobacterium sp., Pseudomonas poae, Delftia acidovorans, Achromobacter xylosoxidans, Enterobacter endosymbiont, Bacillus sp., and Rhodococcus sp., efficiently produce siderophores and rescue plant growth from iron-stress conditions (Tian et al. 2009; Dojima and Craker 2016). Rhizobium meliloti, root-nodulating bacteria isolated from the Mucuna pruriens (a medicinal plant) produces siderophores to promote plant growth (Arora, Kang, and Maheshwari 2001).
Iron-Siderophore and Tumorigenesis
Published in Debasis Bagchi, Manashi Bagchi, Metal Toxicology Handbook, 2020
Sayantan Maitra, Dibyendu Dutta
Regulation of iron homeostasis is essential for all organisms. Free ferric iron can be lethal to cells hence its regulation is necessary. For human, the concentration of ferric ion is kept below 10–24M [5]. The production of siderophores is one of the crucial strategies evolved by bacteria, fungi, and viruses to maintain iron homeostasis. Siderophores are the natural iron chelators, having low molecular weight (400–2,000 Da) and higher affinity for ferric iron. They are produced under the condition of iron deficiency with the aim to scavenge iron, but they also form complexes with other essential elements (Mn, Co, and Ni) available in the environment in order to make them available for microbes [6,7]. Fe3+ ion is a strong Lewis acid and is readily available to form complexes with the electron-pair donors. Siderophores utilize negatively charged oxygen groups as electron donor and thus form a stable complex with iron(III) [8]. Siderophores are mainly classified into three families depending upon the presence of functional group, i.e. hydroxymates, catecholates, and carboxylates. Most of the siderophores geometrically are octahedral, coordinating iron in a thermodynamically stable hexadentate conformation [9].
Transition Metal Encapsulation by “Metallocrown” Ethers
Published in Richard P. Buck, William E. Hatfield, Mirtha UmañA, Edmond F. Bowden, Biosensor Technology Fundamentals and Applications, 2017
Myoung Soo Lah, Vincent L. Pecoraro, Martin L. Kirk, William E. Hatfield
The concept of metallocrowns arises from a marriage of synthetic inorganic chemistry and microbial metal ion sequestration agents. The siderophores are a group of low molecular weight metal ion chelating agents that employ hydroxamate or catecholate moieties to sequester and transport ferric ion into bacterial cells (4). This suggests a biomimetic approach to trivalent transition metal binding using phenolate, catecholate and hydroxamate ligands (5). Indeed, such specificity has been exploited in iron decorporation therapy in the treatment of β-thallesemia (6). One might expect metal selectivity using a ligand, such as salicylhydroxamic acid shown below, that contains two of these functional groups. Furthermore, salicylhydroxamic acid is particularly interesting as three protonation states are available (7): the singly deprotonated hydroxamate (B), the doubly deprotonated hydroximate (C) and the triply deprotonated hydroximatophenolate (D). It is this last form which can be converted into a crown ether analogue.
Mercury resistance and plant growth promoting traits of endophytic bacteria isolated from mercury-contaminated soil
Published in Bioremediation Journal, 2022
Reni Ustiatik, Yulia Nuraini, Suharjono Suharjono, Paramsothy Jeyakumar, Christopher W. N. Anderson, Eko Handayanto
A siderophore is a low molar mass biomolecule (0.5–1.5 kDa) that is produced by a microorganism (bacteria) to scavenge ferric ions through binding to specific high affinity outer membrane receptors (Silva-Stenico et al. 2005). Iron (Fe) is an essential element for plants and can exist in two forms in aqueous solution: Fe2+ and Fe3+. In a Fe limited environment, plants and microbes produce siderophores to solubilize and bind iron (Radzki et al. 2013). Screening of bacteria with siderophore producing traits is an important consideration when assessing the potential beneficial effects of bacteria inoculation on phytoremediation efficiency. The sampling site is a degraded former mining site with low soil fertility, and inoculation of bacteria that will enhance nutrient availability and uptake will be beneficial for plant growth and potentially increase Hg bioaccumulation within plant biomass.
Theoretical insight and experimental elucidation of desferrioxamine B from Bacillus sp. AS7 as a green corrosion inhibitor
Published in Corrosion Engineering, Science and Technology, 2021
S. Pérez-Miranda, L.S. Zamudio-Rivera, R. Cisneros-Dévora, R. George-Téllez, F.J. Fernández
Microbial siderophores are classified as catecholates, hydroxamates and α-carboxylates, depending on the chemical nature of their coordination sites with iron [13,14]. However, some siderophores, like yersiniabactin, are also classified as phenolates [15,16]. Others as ‘mixed’ (e.g. pyoverdine, produced by Pseudomonas species and containing both hydroxamate and catecholate functional groups) [17]. Hydroxamates are produced by fungi and bacteria, among them, actinobacteria are the primary producers of ferrioxamines [18,19], but also by other unrelated families belonging to distantly related bacterial phyla, such as the Gammaproteobacteria [20] and Alphaproteobacteria [21]. Whereas, catecholates are produced exclusively by bacteria [22,23], and comprise catechol and hydroxyl groups as ligands; α-carboxylates are produced by the group of fungal zygomycetes (Mucorales) [24] and a few bacteria, such as Rhizobium meliloti and Staphylococcus hyicus, and coordinate iron through hydroxyl and carboxyl groups [25,26].
Unravelling the necessity of conservation and recycling of rare earth elements from the perspective of global need
Published in Canadian Metallurgical Quarterly, 2022
Siderophores are small, high-affinity iron-chelating compounds secreted by microorganisms such as bacteria, fungi, and grasses. The chelator molecules are produced to hunt Fe+3 from the environment to satisfy the microorganism’s metabolic needs. They are known as the best ligands for ferric ions [85]. Siderophores have a high affinity towards desferrioxamine, which is abundant naturally. The recovery of REEs using siderophores is cost-effective, rapid, reversible, and an eco-friendly technology compared with conventional methods for the recovery of REEs which are available in small concentration from different end-of-life electronic wastes. It has a unique application for the recovery of REEs in the future and can be applied in a vast environmental field [86].