Calcium Export from Neurons and Multi-Kinase Signaling Cascades Contribute to Ouabain Neuroprotection in Hyperhomocysteinemia

Pathological homocysteine (HCY) accumulation in the human plasma, known as hyperhomocysteinemia, exacerbates neurodegenerative diseases because, in the brain, this amino acid acts as a persistent N-methyl-d-aspartate receptor agonist. We studied the effects of 0.1–1 nM ouabain on intracellular Ca2+ signaling, mitochondrial inner membrane voltage (φmit), and cell viability in primary cultures of rat cortical neurons in glutamate and HCY neurotoxic insults. In addition, apoptosis-related protein expression and the involvement of some kinases in ouabain-mediated effects were evaluated. In short insults, HCY was less potent than glutamate as a neurotoxic agent and induced a 20% loss of φmit, whereas glutamate caused a 70% decrease of this value. Subnanomolar ouabain exhibited immediate and postponed neuroprotective effects on neurons. (1) Ouabain rapidly reduced the Ca2+ overload of neurons and loss of φmit evoked by glutamate and HCY that rescued neurons in short insults. (2) In prolonged 24 h excitotoxic insults, ouabain prevented neuronal apoptosis, triggering proteinkinase A and proteinkinase C dependent intracellular neuroprotective cascades for HCY, but not for glutamate. We, therefore, demonstrated here the role of PKC and PKA involving pathways in neuronal survival caused by ouabain in hyperhomocysteinemia, which suggests existence of different appropriate pharmacological treatment for hyperhomocysteinemia and glutamate excitotoxicity

Development of Fruit Diseases of Microbial Origin During Storage at Treatment with Antioxidant Compositions

Present study addresses scientific substantiation of appropriateness of conducting after-harvesting treatment with antioxidant compositions for preventing the development of pathogenic microflora on the surface of fruits during long-term storage. We examined the fruits of apple of the varieties Idared, Golden Delicious, Simirenko Renet, the fruits of pear of the varieties Victoria, Izyuminka Crimea and Cure, the fruits of plum of the varieties Voloshka, Stanley, and Ugorka Italian. The fruits were treated by immersion in the following antioxidant compositions: ACM is a mixture of dimethylsulfoxide, ionol and polyethylene glycols; AARL is a mixture of ascorbic acid, rutine and lecithin; DL is a mixture of dimethylsulfoxide, ionol and lecithin. Control fruits were treated with water. Exposure is 10 seconds. Storage was maintained at a temperature of 0±1 ºC, at relative air humidity 90–95 %. It was established that during preparation of fruits for storing, the largest mean population of epiphytic microflora was registered on the surface of plums and pears with medium term of ripening. The species composition of epiphytic microflora was dominated by spores of mesophilic aerobic and facultative anaerobic microorganisms. Their mean population on the surface of apples was 9.6•103 cfu/g, on the surface of plums – 18•103 cfu/g. Treating all kinds of fruit with AOC significantly decreased speed of growth of both MAFAnM and micromycetes. It is shown that the application of composition reduced the level of daily losses from microbiological diseases over the entire period of storage by 2...3.5 times. The largest positive effect was obtained when applying the composition based on dystynol and lecithin. By performing a multi-factor analysis, it was revealed that the level of daily losses from microbiological diseases during storage was affected by the dominant influence of factors of generic features of fruit raw materials (factor A) and treatment with antioxidant compositions (factor D). The shares of influence are, respectively, 24 and 21