Progress toward clonable inorganic nanoparticles

Abstract

Pseudomonas moraviensis stanleyae was recently isolated from the roots of the Selenium (Se) hyperaccumulator plant Stanleya pinnata. This bacterium tolerates normally lethal concentrations of SeO32− in liquid culture, where it also produces Se nanoparticles. Structure and cellular ultrastructure of the Se nanoparticles as determined by cellular electron tomography shows the nanoparticles as intracellular, of narrow dispersity, symmetrically irregular and without any observable membrane or structured protein shell. Protein mass spectrometry of a fractionated soluble cytosolic material with selenite reducing capability identified nitrite reductase and glutathione reductase homologues as NADPH dependent candidate enzymes for the reduction of selenite to zerovalent Se nanoparticles. In vitro experiments with commercially sourced glutathione reductase revealed that the enzyme can reduce SeO32− (selenite) to Se nanoparticles in an NADPH-dependent process. The disappearance of the enzyme as determined by protein assay during nanoparticle formation suggests that glutathione reductase is associated with or possibly entombed in the nanoparticles whose formation it catalyzes. Chemically dissolving the nanoparticles releases the enzyme. The size of the nanoparticles varies with SeO32− concentration, varying in size form 5nm diameter when formed at 1.0 μM [SeO32−] to 50nm maximum diameter when formed at 100 μM [SeO32−]. In aggregate, we suggest that glutathione reductase possesses the key attributes of a clonable nanoparticle system: ion reduction, nanoparticle retention and size control of the nanoparticle at the enzyme site.

Green synthesis and biotransformation of amorphous Se nanospheres to trigonal 1D Se nanostructures: impact on Se mobility within the concept of radioactive waste disposal

“…Many authors have reported the synthesis of SeNPs coated by organic layers mainly composed of proteins, lipids and polysaccharides. 18,60 Ni et al 61 reported the first 3D electron tomographic analysis of SeIJIV) reduction by the cells of Pseudomonas moraviensis stanleyae providing new insights into the interactions at the nanoparticle/protein interface. They identified the first polypeptide playing a major role in the reduction of SeIJIV) and formation of intracellular of SeNPs.…”

The Metalloid Reductase of Pseudomonas Moravenis Stanleyae Conveys Nanoparticle Mediated Metalloid Tolerance

“…12 We recently reported on the ability of glutathione reductase (GSHR) to enzymatically reduce selenite (SeO 3 2-) to zerovalent red selenium in a nicotinamide adenine dinucleotide phosphate (NADPH) dependent reaction. 13 Similar, although diminished activity, was observed for the same enzyme in reducing tellurite (TeO 3 2-) to elemental Te. Our prior work identified selenite reductase activity in Pseudomonas moravenis stanleyae.…”

“…13 We examined the GRLMR for similar behavior. Selenium particles were synthesized in vitro and were separated from the solution using centrifugation.…”

“…13 In the present study, we characterize a homologous metalloid reductase from the seleno-specialist P. moravenis. We find that the substrate selectivity of the metalloid reductase (K M ) shows a substantially larger preference for GS-Se-SG relative to all other reported glutathione reductase enzymes.…”

A review of nature-based solutions for resource recovery in cities

“…As a solution to its scarcity, Se could be recovered from industrial, secondary resources, such as effluents of flue gas desulphurisation (FGD), using cost-effective and environmental-friendly biotechnological approaches (Cordoba & Staicu 2018). Various bacterial groups can metabolise Se to generate cellular energy (i.e., Downloaded from http://iwaponline.com/bgs/article-pdf/2/1/138/740604/bgs0020138.pdf ATP) through anaerobic respiration, in parallel with the production of solid Se nanoparticles (Ni et al 2015), as displayed in Figure 2.…”