Quercus robur (L.) and Q. petraea (Matt.) Liebl. are European oak species that often grow in forest soils with high soluble manganese (Mn2+) concentrations. We tested the effects of Mn2+ at concentrations of 0.0024 mM (control), 0.24 mM (typical of acidic forest soils) and 1.2 mM (typical of forest soils under strongly reducing conditions) on the growth, tissue anatomy, foliar element concentra...

antioxidant are the agents which dispose / scavenge the reactive oxygen species, minimize the oxidative stress / lipid peroxidation and ultimately improve the fertilizing potential of the spermatozoa. currently, many antioxidants are under investigation and manganese is one of them in reducing the oxidative stress both in male and female. the antioxidative action of manganese (mn2+) on various ...

Arseniopleite, ideally (Ca,Na) (Na,Pb2+) Mn2+ (Mn,Mg,Fe)2 As3 O12, is monoclinic, a 6.8113(6), b 13.0358(11), c 11.3245(10) Å, 100.25(3)°, V 989.5(1) Å3, I2/a, Z = 2, has been refined to an R index of 2.3% for 1280 observed (| Fo | ≥ 4 F) reflections measured with a Bruker P4 diffractometer equipped with a CCD detector and MoK X-radiation. The crystal used for the collection of the X-ray intens...

Electrothermal atomic-absorption spectroscopy was employed for measuring manganese in beta-cell-rich pancreatic islets isolated from ob/ob mice. The efflux from preloaded islets was estimated from the amounts remaining after 30 min of subsequent test incubations in the absence of Mn2+. An increase in the extracellular Mg2+ concentration promoted the Mn2+ efflux and removal of Na+ from a Ca2+-de...

Electron paramagnetic resonance of Mn2+ and Gd3+ in single crystals of Pr2Co3(N03)i2 • 24 H2O has been studied at X-band at 305 and 77 K. Mn2+ substitutes at two types of Co2 f sites whereas Gd3 substitutes at the single type of Pr3+ site in the lattice. The spin-Hamiltonian parameters have been evaluated. Observation of resolved Mn2+ and Gd3+ spectra at 305 K and their broadening on lowering t...

The effects of varying concentrations of Mn2* on the absorption of divalent cations, viz., Ca2+ and Zn2+ from 2 concentrations were studied. Mn2+ at all concentrations tested were inhibitory to Ca2+ uptake from 0.1 and 5 mM CaCl2 . However, when Ca2+ uptake was measured at concentrations ranging from 0.05 to 10 mM CaCl2, MnCl2 only at high concentration of 5 mM, inhibited Ca ab­ sorption. Zn2+ ...

Differentiation of HL60 cells by treatment with dimethyl sulphoxide induces the expression of membrane receptors for N-formylmethionyl-leucyl-phenylalanine (fMLP) and for platelet-activating factor (PAF). In these cells both agonists produced an increase in the cytosolic Ca2+ concentration ([Ca2+]i) by release of Ca2+ from the intracellular stores, followed shortly by an acceleration of the ent...

Metal ion requirements for the proliferation of Saccharomyces cerevisiae were investigated. We used bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA), a relatively acid tolerant chelator, to reduce the free metal ion concentrations in culture media. Chelatable metal ions were added back individually and in combination. In addition to a requirement for approximately 10 pM external f...

Human immunodeficiency virus (HIV) RNase H activity is essential for the synthesis of viral DNA by HIV reverse transcriptase (HIV-RT). RNA cleavage by RNase H requires the presence of divalent metal ions, but the role of metal ions in the mechanism of RNA cleavage has not been resolved. We measured HIV RNase H activity associated with HIV-RT protein in the presence of different concentrations o...