Intranasal exposure to manganese induces activation of calpains in rat striatum

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Abstract

Abstract. Chronic manganese (Mn) exposure causes a variety of psychiatric and motor disturbances, termed manganism. Here, we provide an evidence to support the involvement of the calcium-dependent proteases, calpains, in the pathogenesis of manganism in a rat model. 20 male rats were divided randomly into two groups: the control group and the Mn exposure group. The rats in the Mn exposure group received intranasal injection of 1 mg/rat MnCl 2 ×4H 2 O once a day for 90 days. The control group rats received intranasal injection of physiological saline the same way. The levels of Mn in the striatum (Str) were assessed using atomic absorption spectroscopy. Mn levels were found to be significantly higher in the experimental group of rats than in the control group. Further, the involvement of calpain-1 and calpain-2 was monitored in the Str. The activity of calpain-1/2 was determined by casein zymography. It was revealed, that Mn induced an increase of the activity of calpain-2 in the Str, where the activity of calpain-1 was also increased. We have also shown that Mn directly activates calpain-1 like calcium but not calpain-2. We propose that calpains can be potential therapeutic targets for manganism. 

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Manganese Toxicity Upon Overexposure: a Decade in Review.

Stefanie L O'Neal, Wei-Wei Zheng (2015)

Exposure to manganese (Mn) causes clinical signs and symptoms resembling, but not identical to, Parkinson's disease. Since our last review on this subject in 2004, the past decade has been a thriving period in the history of Mn research. This report provides a comprehensive review on new knowledge gained in the Mn research field. Emerging data suggest that beyond traditionally recognized occupational manganism, Mn exposures and the ensuing toxicities occur in a variety of environmental settings, nutritional sources, contaminated foods, infant formulas, and water, soil, and air with natural or man-made contaminations. Upon fast absorption into the body via oral and inhalation exposures, Mn has a relatively short half-life in blood, yet fairly long half-lives in tissues. Recent data suggest Mn accumulates substantially in bone, with a half-life of about 8-9 years expected in human bones. Mn toxicity has been associated with dopaminergic dysfunction by recent neurochemical analyses and synchrotron X-ray fluorescent imaging studies. Evidence from humans indicates that individual factors such as age, gender, ethnicity, genetics, and pre-existing medical conditions can have profound impacts on Mn toxicities. In addition to body fluid-based biomarkers, new approaches in searching biomarkers of Mn exposure include Mn levels in toenails, non-invasive measurement of Mn in bone, and functional alteration assessments. Comments and recommendations are also provided with regard to the diagnosis of Mn intoxication and clinical intervention. Finally, several hot and promising research areas in the next decade are discussed.

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Characterization of silver nanoparticles synthesized by using marine isolate Streptomyces albidoflavus.

Girija Shankar Guntuku, Sudheer Kumar Yannam, Reddy Shetty Prakasham … (2012)

Silver nanoparticles production by the green chemistry approach was investigated using an isolated marine actinomycetes strain. The isolated strain was identified as Streptomyces albidoflavus based on chemotaxonomic and ribotyping properties. The strain revealed production of silver nanoparticles both extracellular and intracellularly. Surface Plasmon Resonance analysis with the function of time revealed that particle synthesis by this strain is reaction time dependent. The produced particles were spherical shaped and monodispersive in nature and showed a single surface plasmon resonance peak at 410 nm. Size distribution histograms indicated production of 10-40- nm-size nanoparticles with a mean size of 14.5 nm. FT-IR spectra of nanopartilces showed N-H, C-H, and C-N stretching vibrations, denoting the presence of amino acid/ peptide compounds on the surface of silver nanoparticles produced by S. albidoflavus. Synthesized nanoparticles revealed a mean negative zeta potential and electrophoretic mobility of -8.5 mV and -0.000066 cm2/Vs, respectively. The nanoparticles produced were proteinaceous compounds as capping agents with -8.5 mV zeta potential and revealed antimicrobial activity against both Gram-negative and -positive bacterial strains. Owing to their small size, these particles have greater impact on industrial application spectra.

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Micro-dissection of rat brain for RNA or protein extraction from specific brain region.

Kin Chiu, Benson Wui-Man Lau, Ho-Tak Lau … (2007)

Micro-dissection of rat brain into various regions is extremely important for the study of different neurodegenerative diseases. This video demonstrates micro-dissection of four major brain regions include olfactory bulb, frontal cortex, striatum and hippocampus in fresh rat brain tissue. Useful tips for quick removal of respective regions to avoid RNA and protein degradation of the tissue are given.