Manganese induced changes in growth, chlorophyll content and antioxidants activity in seedlings of broad bean (Vicia faba L.).

The effect of manganese(Mn) on broad bean (Vicia faba L.) was studied with regard to growth, Mn accumulation in root and shoot, chlorophyll, proline content and peroxidase activity. Seeds were treated with Mn (10, 20, 40, 80,120,160 μM) and grown hydroponically up to 15 days. Manganese level in both root and shoot increased progressively in response to increasing concentration and it was high in roots (13 fold) over the shoots (8 fold). The reductions in root (52%) and shoot (62.92%) development were evident for the maximum Mn concentration (160 μM). The chlorophyll amount gradually declined with increasing Mn concentrations and attained its maximum (42%) at 160 μM. By contrast, the guaiacol peroxidase activity was high (71%) along with the accompanying rise in proline content (75%) in shoots of the highest Mn concentration (160 μM). However, there was about 2 fold increase in total glutathione content at 40 μM than the basal level and further declined to 21.65 Cg g-1 fresh wt. at 160 μM Mn. The alterations in overall reflected Mn concentration- dependent changes in the parameters studied. The results suggest that the plant Vicia faba L. copes with Mn exposure through enhanced production of antioxidants.

Nitric Oxide-Mediated Cytotoxicity of Manganese in Basal Ganglia Neuronal Cells / 예방의학회지

OBJECTIVES: We have investigated to manifest whether manganese-induced neurotoxicity is mediated by nitric oxide(NO) in the rat primary neuronal cultures and assess the effect of Mn2+ on the N-methyl-D aspartate(NMDA) receptors. METHODS: We have used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)assay to examine the effect of cytotoxicity of MnCl2 in neuronal cells . NO production was determined by measuring nirites, a stable oxidation product of NO. The neurons in the rat that contains neuronal nitric oxide synthase(nNOS) were examined by immunofluorescence and confocal microscopy. The effects of Mn2+ on the NMDA receptors was assesed by the whole cell voltage clamp technique. RESULTS: We showed that the NO release and NOS expression were increased with 500uM MnCl2 treatment and an NOS inhibitors, NG-nitro-L-arginine , prevented neurotoxicity elicited by manganese. In the electrophysiological study, Mn2+ does not block or activate the NMDA receptors and not pass through the NMDA receptors in a neurons of basal ganglia. CONCLUSIONS: It is concluded that manganese neurotoxicity in basal ganglia was partially mediated by nitric oxide in the cell culture model.