Studies on the nature of interaction of iron(III) with alginates

Sreeram, Kalarical Janardhanan; Shrivastava, H. Yamini; Nair, Balachandran Unni

doi:10.1016/j.bbagen.2003.11.001

Cited by 102 publications

(46 citation statements)

References 19 publications

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“…We suggest that a slightly restricted diffusion of the xenobiotic through the Caalginate matrix could occur. Also, iron could partly replace Ca in the gel matrix ([Min and Hering, 1998] and [Sreeram et al, 2004]) avoiding its uptake by the bacteria and thus the activation of bacterial degradative enzymes. All these results show that mechanisms observed with free cells can be extrapolated to entrapped cells, i.e.…”

Section: Discussionmentioning

confidence: 99%

“…A breaking-up of alginate beads is observed with time: interactions between the units of sugar and the calcium cation responsible for the gelling are probably replaced by interactions with iron cation. This exchange of cation makes iron unavailable in alginate experiments and explains the difference of total iron concentrations between the two systems (Sreeram et al, 2004). …”

Section: Combined Bio-and/or Photodegradation Processmentioning

confidence: 99%

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2-Aminobenzothiazole degradation by free and Ca-alginate immobilized cells of Rhodococcus rhodochrous

et al. 2009

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2-Aminobenzothiazole (ABT) degradation was investigated using free and immobilized systems during photodegradation under solar light in the presence of Fe(III)-nitrilotriacetic acid (FeNTA), biodegradation by Rhodococcus rhodochrous, and during combined conditions. Ca-alginate hydrogel was chosen as a model matrix and some complementary studies were required to characterize this new system. R. rhodochrous metabolism in this type of environment was monitored by NMR spectroscopy. Neither change in intracellular pH values nor in ATP concentrations was observed by in vivo 31 P NMR, showing that no metabolic modification occurred between free and immobilized cells.1 H NMR demonstrated that alginate was not used as carbon source by R. rhodochrous. After establishing the pre-treatment protocol by SPE to eliminate solubilised alginate, ABT adsorption on beads and degradation were studied. The same pathways of transformation were observed in suspended and immobilized cell systems. Considering the ABT adsorption phenomenon on alginate beads (8%), the efficiency of the two systems was found to be comparable although the degradation rate was slightly lower with immobilized cells. The most important result was the finding that the positive effect of FeNTA on ABT degradation with immobilized cells was similar to that observed previously with free cells. All these results show that mechanisms observed with free cells can be extrapolated to entrapped cells, i.e. under conditions much closer to those usually encountered in the environment.

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Section: Discussionmentioning

confidence: 99%

Section: Combined Bio-and/or Photodegradation Processmentioning

confidence: 99%

2-Aminobenzothiazole degradation by free and Ca-alginate immobilized cells of Rhodococcus rhodochrous

et al. 2009

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“…This difference in coordination chemistry of iron(III) and iron(II) cations has been previously utilized for speciation of iron(II) and iron(III) cations in solution, for preparation of molecular switches [53], and for mechanical actuation of hydrogels [54]. Iron(III) cations form stable alginate hydrogels [55] that have been successfully used as a support for growth of cell cultures [56,57]. While iron(II) cations are also capable of cross-linking of alginate [58] this process requires substantially higher concentration of ferrous cations while 20-30 mM solutions of iron(II) salts in 0.8%-1.2% w/v sodium alginate are viscous homogeneous liquids.…”

Section: Open Accessmentioning

confidence: 99%

Photochemical Patterning of Ionically Cross-Linked Hydrogels

2013

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Iron(III) cross-linked alginate hydrogel incorporating sodium lactate undergoes photoinduced degradation, thus serving as a biocompatible positive photoresist suitable for photochemical patterning. Alternatively, surface etching of iron(III) cross-linked hydrogel contacting lactic acid solution can be used for controlling the thickness of the photochemical pattering. Due to biocompatibility, both of these approaches appear potentially useful for advanced manipulation with cell cultures including growing cells on the surface or entrapping them within the hydrogel.

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“…Uronic acids, for example, are likely to be significant for iron biogeochemistry; they are a major constituent of the natural saccharides found in surface waters, as well as in the EPS excreted by eukaryotic phytoplankton and heterotrophic and autotrophic bacteria (24, 26-29, 35, 36). The carboxylic groups of uronic acids are known to bind transition metals, including iron(III) (19,35,37). To understand the underlying mechanisms by which saccharides (including uronic acids) alter iron bioavailability to eukaryotic phytoplankton, we measured the intracellular iron uptake, chemical complexation, and solubility with and without the addition of organic ligands (two saccharides, one bacterial EPS, and one siderophore).…”

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confidence: 99%

Saccharides enhance iron bioavailability to Southern Ocean phytoplankton

Hassler

Schoemann

Nichols

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

254

218

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Iron limits primary productivity in vast regions of the ocean. Given that marine phytoplankton contribute up to 40% of global biological carbon fixation, it is important to understand what parameters control the availability of iron (iron bioavailability) to these organisms. Most studies on iron bioavailability have focused on the role of siderophores; however, eukaryotic phytoplankton do not produce or release siderophores. Here, we report on the pivotal role of saccharides-which may act like an organic ligand-in enhancing iron bioavailability to a Southern Ocean cultured diatom, a prymnesiophyte, as well as to natural populations of eukaryotic phytoplankton. Addition of a monosaccharide (>2 nM of glucuronic acid, GLU) to natural planktonic assemblages from both the polar front and subantarctic zones resulted in an increase in iron bioavailability for eukaryotic phytoplankton, relative to bacterioplankton. The enhanced iron bioavailability observed for several groups of eukaryotic phytoplankton (i.e., cultured and natural populations) using three saccharides, suggests it is a common phenomenon. Increased iron bioavailability resulted from the combination of saccharides forming highly bioavailable organic associations with iron and increasing iron solubility, mainly as colloidal iron. As saccharides are ubiquitous, present at nanomolar to micromolar concentrations, and produced by biota in surface waters, they also satisfy the prerequisites to be important constituents of the poorly defined "ligand soup," known to weakly bind iron. Our findings point to an additional type of organic ligand, controlling iron bioavailability to eukaryotic phytoplankton-a key unknown in iron biogeochemistry.trace metals | carbohydrates | organic matter | exopolymeric substances | plankton

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Studies on the nature of interaction of iron(III) with alginates

Cited by 102 publications

References 19 publications

2-Aminobenzothiazole degradation by free and Ca-alginate immobilized cells of Rhodococcus rhodochrous

2-Aminobenzothiazole degradation by free and Ca-alginate immobilized cells of Rhodococcus rhodochrous

Photochemical Patterning of Ionically Cross-Linked Hydrogels

Saccharides enhance iron bioavailability to Southern Ocean phytoplankton

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