This study explores Mn biogeochemistry in a stratified, ferruginous lake, a modern analogue to ferruginous oceans. Intense Mn cycling occurs in the chemocline where Mn is recycled at least 15 times before sedimentation. The product of biologically catalyzed Mn oxidation in Lake Matano is birnessite. Although there is evidence for abiotic Mn reduction with Fe(II), Mn reduction likely occurs thro...

Manganese (Mn), upon absorption, is primarily sequestered in tissue and intracellular compartments. For this reason, blood Mn concentration does not always accurately reflect Mn concentration in the targeted tissue, particularly in the brain. The discrepancy between Mn concentrations in tissue or intracellular components means that blood Mn is a poor biomarker of Mn exposure or toxicity under m...

Manganese (Mn) is an important mineral element required in trace amounts for development of the human body, while over- or chronic-exposure can cause serious organ toxicity. The current study was designed to evaluate the protective role of quercetin (Qct) against Mn-induced toxicity in the liver, kidney, lung, and hematological parameters in acute and subchronic rat models. Male Sprague Dawley ...

Soluble manganese(III) [Mn(III)] has been thought to disproportionate to soluble Mn(II) and particulate Mn(IV)O2 in natural waters, although it persists as complexes in laboratory solutions. We report that, in the Black Sea, soluble Mn(III) concentrations were as high as 5 micromolar and constituted up to 100% of the total dissolved Mn pool. Depth profiles indicated that soluble Mn(III) was pro...

Manganese (Mn) is an essential trace element for plants. Recently, the genes responsible for uptake of Mn in plants were identified in Arabidopsis and rice. However, the mechanism of Mn distribution in plants has not been clarified. In the present study we identified a natural resistance-associated macrophage protein (NRAMP) family gene in rice, OsNRAMP3, involved in Mn distribution. OsNRAMP3 e...

Manganese (Mn) is an essential nutrient for intracellular activities; it functions as a cofactor for a variety of enzymes, including arginase, glutamine synthetase (GS), pyruvate carboxylase and Mn superoxide dismutase (Mn-SOD). Through these metalloproteins, Mn plays critically important roles in development, digestion, reproduction, antioxidant defense, energy production, immune response and ...

Reactive Mn(IV) oxide minerals are ubiquitous in the environment and control the bioavailability and distribution of many toxic and essential elements and organic compounds. Their formation is thought to be dependent on microbial enzymes, because spontaneous Mn(II) to Mn(IV) oxidation is slow. Several species of marine Bacillus spores oxidize Mn(II) on their exosporium, the outermost layer of t...

This study was aimed at investigating the bioefficacy of organic compared with inorganic manganese (Mn) for eggshell quality. An amino acid-Mn complex or Mn sulfate monohydrate was used as the organic or inorganic Mn source. A total of six hundred forty-eight 50-wk-old layers (Hy-Line Brown) were divided into 9 groups; each group consisted of 6 replicates with 12 layers each. The feeding trial ...