In recent decades, considerable efforts have been made to understand the mechanism of memory, cognition, and relevant neurodegenerative diseases in the human brain. Several studies have shown the importance of microtubule proteins in the memory mechanism and memory dysfunction. Microtubules possess dynamicity, which is essential for functions of neuronal networks. Microtubule-associated proteins, i.e., tau, play vital roles in microtubule stability. On the other hand, the ferromagnetic mineral magnetite (Fe(3)O(4)) has been detected in the normal human brain, and elevated levels of magnetite are also observed in the brains of Alzheimer's disease patients. Therefore, we propose that a relationship between microtubule organization in axons and brain magnetite nanoparticles is possible. In this study we found alterations of microtubule polymerization in the presence of increasing concentrations of magnetite through transmission electron microscopy images and a turbidimetry method. Structural changes of microtubule and tau protein, as an essential microtubule-associated protein for tubulin assembly, were detected via circular dichroism spectroscopy, intrinsic fluorescence, and 8-anilino-1-naphthalenesulfonic acid fluorometry. We predicted three possible binding sites on tau protein and one possible binding site on tubulin dimer for magnetite nanoparticles. Magnetite also causes the morphology of PC12 cells to change abnormally and cell viability to decrease. Finally, we suggest that magnetite changes microtubule dynamics and polymerization through two paths: (1) changing the secondary and tertiary structure of tubulin and (2) binding to either tubulin dimer or tau protein and preventing tau-tubulin interaction.

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Background:Physical exercises can influence some anthropometric and fitness components differently. The aim of present study was to evaluate how a relatively long-term training program in 11-14-year-old male Iranian students affects their anthropometric and motor performance measures.Methods:Measurements were conducted on the anthropometric and fitness components of participants (n = 28) prior to and following the program. They trained 20 weeks, 1.5 h/session with 10 min rest, in 4 times trampoline training programs per week. Motor performance of all participants was assessed using standing long jump and vertical jump based on Eurofit Test Battery.Results:The analysis of variance (ANOVA) repeated measurement test showed a statistically significant main effect of time in calf girth P = 0.001, fat% P = 0.01, vertical jump P = 0.001, and long jump P = 0.001. The ANOVA repeated measurement test revealed a statistically significant main effect of group in fat% P = 0.001. Post hoc paired t-tests indicated statistical significant differences in trampoline group between the two measurements about calf girth (t = −4.35, P = 0.001), fat% (t = 5.87, P = 0.001), vertical jump (t = −5.53, P = 0.001), and long jump (t = −10.00, P = 0.001).Conclusions:We can conclude that 20-week trampoline training with four physical activity sessions/week in 11–14-year-old students seems to have a significant effect on body fat% reduction and effective results in terms of anaerobic physical fitness. Therefore, it is suggested that different training model approach such as trampoline exercises can help students to promote the level of health and motor performance.

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Recently, the hypothesis in which memory and information would be stored as magnetic forms in astrocytes is expanding and neuromagnetic interactions between neurons and neighboring astrocytes in neocortex have potential to be the basis of memory formation. It has been proposed that all sorts of information may be maintained in form of neuronal activity-associated magnetic fields (NAAMFs) and thereby alterations of magnetic fields in the brain may potentially affect the memory function. On the other hand, microtubules (MTs), the most essential elements of cytoskeleton, are crucial in regulation of spine development and morphology, brain cognitive behavior, consciousness and information storage. Because of MT dynamic nature, it can produce local magnetic field in neurons through vibration. According to size, number, structure and function of microtubule proteins, they are the most eligible components of neurons to be affected by endogenous and exogenous magnetic fields. In this study we tried to investigate the possible effects of exogenous static magnetic fields (SMFs) on memory through examining the structural and functional changes in MT dynamic activity and neural cell morphology. MT activity results revealed that MT polymerization process was not attained to steady state at the right time in the presence of SMF at 300 mT and the ascending slope at the steady state phase was found as abnornmal. In addition, MT structure was relatively changed. On the influence of SMF, PC12 neuron-liked cells' spines decreased significantly and their morphology altered to pyramidal form.