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Beneficial effects of dietary restriction on cerebral cortical synaptic terminals: Preservation of glucose and glutamate transport and mitochondrial function after exposure to amyloid β-peptide, iron, and 3-nitropropionic acid

Abstract : Recent studies have shown that rats and mice maintained on a dietary restriction (DR) regimen exhibit increased resistance of neurons to excitotoxic, oxidative, and metabolic insults in experimental models of Alzheimers, Parkinsons, and Huntingtons diseases and stroke. Because synaptic terminals are sites where the neurodegenerative process may begin in such neurodegenerative disorders, we determined the effects of DR on synaptic homeostasis and vulnerability to oxidative and metabolic insults. Basal levels of glucose uptake were similar in cerebral cortical synaptosomes from rats maintained on DR for 3 months compared with synaptosomes from rats fed ad libitum. Exposure of synaptosomes to oxidative insults (amyloid β‐peptide and Fe2+) and a metabolic insult (the mitochondrial toxin 3‐nitropropionic acid) resulted in decreased levels of glucose uptake. Impairment of glucose uptake following oxidative and metabolic insults was significantly attenuated in synaptosomes from rats maintained on DR. DR was also effective in protecting synaptosomes against oxidative and metabolic impairment of glutamate uptake. Loss of mitochondrial function caused by oxidative and metabolic insults, as indicated by increased levels of reactive oxygen species and decreased transmembrane potential, was significantly attenuated in synaptosomes from rats maintained on DR. Levels of the stress proteins HSP‐70 and GRP‐78 were increased in synaptosomes from DR rats, consistent with previous data suggesting that the neuroprotective mechanism of DR involves a “preconditioning” effect. Collectively, our data provide the first evidence that DR can alter synaptic homeostasis in a manner that enhances the ability of synapses to withstand adversity.

Molecular Imprinting Technology in Quartz Crystal Microbalance (QCM) Sensors.

Molecularly imprinted polymers (MIPs) as artificial antibodies have received considerable scientific attention in the past years in the field of (bio)sensors since they have unique features that distinguish them from natural antibodies such as robustness, multiple binding sites, low cost, facile preparation and high stability under extreme operation conditions (higher pH and temperature values, etc.). On the other hand, the Quartz Crystal Microbalance (QCM) is an analytical tool based on the measurement of small mass changes on the sensor surface. QCM sensors are practical and convenient monitoring tools because of their specificity, sensitivity, high accuracy, stability and reproducibility. QCM devices are highly suitable for converting the recognition process achieved using MIP-based memories into a sensor signal. Therefore, the combination of a QCM and MIPs as synthetic receptors enhances the sensitivity through MIP process-based multiplexed binding sites using size, 3D-shape and chemical function having molecular memories of the prepared sensor system toward the target compound to be detected. This review aims to highlight and summarize the recent progress and studies in the field of (bio)sensor systems based on QCMs combined with molecular imprinting technology.

Resuable Pectinase Nano Polymeric Particles

Pectinase or pectinolytic enzymes are the group of enzymes that degrade the pectin substances.They have great importance in food industry especially for the production of clear fruit juice. In this study, a new method has been developed for hydrolysis of pectin by using nano pectinase particles in hydrolysis of pectin. At the first step of the study, nano pectinase particles have been synthesized according to Amino Acid (monomer) Decorated and Light Underpinning Conjugation Approach (ANADOLUCA) method and characterized by transmission electron microscopy (TEM) and zeta sizer. In the second step, the hydrolysis of pectin has been investigated using newly synthesized nano pectinase particles and free pectinase enzyme separately and compared to each other. The different conditions that affect the hydrolysis of pectin such as pH, thermal stability, storage stability and reusability have been investigated. Then, the activity of nanopectinase particles and free pectinase enzyme has been analyzed in terms of Michaelis- Menten parameters comparatively. In addition to these studies, the reusability data of nano pectinase particles has been showed a great potential as reusable catalyst when compared to free enzyme. So, the newly synthesized nano pectinase particles are very attractive for hydrolysis of pectin substances and they will have a great usage area in industrial process.