Host plant-derived allelochemicals and metal components are associated with oxidative predominance and antioxidant plasticity in the larval tissues of silkworm, Antheraea mylitta: Further evidence of joint effects hypothesis.

Tasar silkworm, Antheraea mylitta is a polyphagous insect that primarily feeds on Terminalia arjuna, Terminalia tomentosa and Shorea robusta. However, larval rearing on S. robusta results in poor performance for the reasons unexplored. Oxidative burden imposed by host plants is presumed to be a determining factor for larval fitness. With this hypothesis we have analyzed the foliar constituents of the respective host plants, the levels of oxidative stress and antioxidant protection in the larval tissues in response to their altered feeding on different host plants for different durations (2 and 10 days). Results indicate that S. robusta leaves contain the highest amount of tannin and redox active metals compared to those of other host plants. Consequently, hemolymph and midgut tissues of the larvae shifted to S. robusta exhibited oxidative predominance. Increased activities of superoxide dismutase, catalase and glutathione S-transferase in the larval tissues indicated an adaptive response to host plant driven oxidative assault. Our in vitro study also strongly supplements the in vivo findings indicating S. robusta foliages as a strong inducer of lipid peroxidation (LPx). Copper and Iron were found to be more potent in inducing LPx in the midgut tissues of the larvae compared to Zinc and Manganese. This study for the first time demonstrates the combined implications of host plant derived allelochemicals and elements on oxidative stress and antioxidant plasticity in this insect. The overall findings also brace up the newly emerging concept on joint effects hypothesis (organic and elemental defence) for enhanced plant defence.

Trace elemental distribution in the scalp hair of bipolars using PIXE technique.

Trace metals play a significant role in neurological disorders. There is very limited information available on the role of macro and trace elements in bipolar disorders. The objective of this investigation was to identification, quantification of essential trace elements in the scalp hair samples of the patients and compare with those of normal subjects. We made a hypothesis about the role played by essential trace metals whose concentrations are significantly different to those of normals in the disease process. The analysis was carried out in the scalp hair samples of 26 male and 26 female patients suffering from bipolar disorder (BD) by Particle Induced X-ray Emission Technique (PIXE). The concentration of Cu (p < 0.002) was found to be higher in the hair samples of male bipolar disorder patients while the concentrations of Mn (p < 0.001), Fe (p < 0.005), Zn (p < 0.0001) and Se (p < 0.005) were found to be lower than those in normal subjects. The concentration of Cu (p < 0.0001) was higher in the hair samples of female bipolar patients but depressed levels of Fe (p < 0.005), Ni (p < 0.05), Zn (p < 0.00001) and Se (p < 0.05) were observed compared to controls. Cu/Zn ratio was found to be higher in the hair samples of male and female patients compared with normals. While the imbalance of certain trace elements leads to generation of more free radicals, the imbalance of some other trace elements causes changes in dopamine (neurotransmitter) activity. It is essential to monitor before and periodically during treatment the levels of essential trace elements for effective treatment of bipolar disorder.