Iron and manganese complexes with derivatives of bis(2-pyridylmethyl)-1,2-ethanediamine (bispicen) have previously been found to be efficient catalysts for hydrocarbon oxygenation. Methylation can potentially impact the conformation of the ligand around the metal center and the electronic character of the bound metal ion; each of these, in turn, impacts reactivity. Reported are mononuclear mang...

Euglena gracilis (Klebs) cultures were grown under conditions where limitation in supply of manganese limited chlorophyll content much more than growth. Although the initial rates of photosynthetic oxygen evolution were not affected by the level of manganese, photoinhibition in high intensity light was markedly influenced. All cultures showed first order kinetics for photoinhibition, with the h...

We report an in situ soft chemical synthesis of a novel hybrid material, cellulose-nanoscale-manganese oxide composite (C-NMOC), and its application for Pb(II) removal from aqueous solutions. For comparison, detailed Pb(II) adsorption studies were also performed with nanoscale-manganese oxide powder (NMO), prepared through a similar route. Various spectroscopic and microscopic techniques were u...

UNLABELLED Several species of the bacterial genus Shewanella are well-known dissimilatory reducers of manganese under anaerobic conditions. In fact, Shewanella oneidensis is one of the most well studied of all metal-reducing bacteria. In the current study, a number of Shewanella strains were tested for manganese-oxidizing capacity under aerobic conditions. All were able to oxidize Mn(II) and to...

hydrous manganese dioxide nanoclusters are prepared by the oxidation of manganese (ii) ions with ammonium persulfate and used as a new sorbent for ag+ ion removal from aqueous medium. the synthesized compound is characterized using scanning electron microscopy, dynamic light scattering, energy dispersive analysis of x-rays, x-ray diffraction and bet surface measurements. scanning electron micro...

Electron spin echo electron-nuclear double resonance (ESE-ENDOR) experiments performed on a broad radical electron paramagnetic resonance (EPR) signal observed in photosystem II particles depleted of Ca2+ indicate that this signal arises from the redox-active tyrosine YZ. The tyrosine EPR signal width is increased relative to that observed in a manganese-depleted preparation due to a magnetic i...

Manganese is an essential element required by cyanobacteria, as it is an essential part of the oxygen-evolving center of photosystem II. In the presence of atmospheric oxygen, manganese is present as manganese oxides, which have low solubility and consequently provide low bioavailability. It is unknown if cyanobacteria are able to utilize these manganese sources, and what mechanisms may be empl...

Clickable ligands like N,N'-bis((pyridin-2-yl)methyl)prop-2-yn-1-amine (L(1)) and N-((1-methyl-1H-imidazol-2-yl)methyl)-N-(pyridin-2-ylmethyl)prop-2-yn-1-amine (L(2)) have been used to synthesise a series of manganese(ii) complexes for grafting onto appropriate solid supports. These ligands mimic the 2-His-1-carboxylate facial chelation present in the active site of the manganese-dependent diox...

Photosystem II complexes were solubilized with the detergent sulfobetaine 12 from thylakoid membranes of the thermophilic cyanobacterium Synechococcus sp. and purified by two sucrose gradient centrifugations and by chromatography on a Mono Q column. In such pho­ tosystem II complexes having a photosynthetic O, evolving activity of 2938 |amol 0 2 evolved/ mg chlorophyll x h, an L-arginine metabo...

The effects of zinc and manganese on the reductive dissolution of hematite by the dissimilatory metal-reducing bacterium (DMRB) Shewanella putrefaciens CN32 were studied in batch culture. Experiments were conducted with hematite (2.0 g L 1) in 10 mM PIPES (pH 6.8), and H2 as the electron donor under nongrowth conditions (108 cell mL 1), spiked with zinc (0.02–0.23 mM) or manganese (0.02–1.8 mM)...