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Salt stress was shown to cause changes in the activity and isozyme composition of mitochondrial malate dehydrogenase (MDH) in leaves of amaranth (C4-type); these changes were manifested in the induction of an additional MDH isoform. Exposure of spinach plants (C3-type) to a NaCl solution did not cause significant changes in the isozyme composition and activity of the enzymes studied. Succinate dehydrogenase (SDH) activity in amaranth leaves under salt stress conditions increased several times, while the isoenzyme composition of SDH remained unchanged. The levels of gene transcripts in leaves of amaranth and spinach clearly correlated with changes in the MDH and SDH activity. Salt stress enhanced expression of the mdh-mtx (mitochondrial) and mdh-cyt (cytoplasmic) genes in amaranth leaves during the whole experiment. In the case of the sdha gene, a decrease in the content of transcripts was observed that clearly correlated with the reduction in SDH activity.

Immunostimulatory properties of extracellular heat shock proteins 70 kDa (HSP70) became interesting for investigators a long time ago. However, in recent years a series of works showing a significant relation of the immunostimulating effects of recombinant HSP70 to contamination of the protein samples with bacterial endotoxins (lipopolysaccharide, LPS) has been published. The authors showed that intensive elimination of LPS from the protein samples resulted in inversion of immunostimulating effects of HSP70 to immunosuppressive activity of the protein. Nevertheless, at present the conception of immunostimulating, proinflammatory action of extracellular HSP70 is the most common. In this work, we studied immunomodulatory effects of exogenous HSP70 in a mouse model of allergic inflammation of airways. We also analyzed the dynamics of the level of the extracellular pool of HSP70 in the site of inflammation. The results demonstrated a considerable content of extracellular HSP70 in bronchoalveolar lavages with dynamics reflecting the stages of development of the induced inflammation. Oropharyngeal injection of exogenous HSP70 in the acute phase of allergic inflammation of airways resulted in significant suppression of the inflammatory process, which conforms to published data demonstrating an immunosuppressive activity of the extracellular pool of HSP70.

In maize (Zea mays L., cv. Voronezhskaya-76) seedlings subjected to salinity, the values of indicators of stress response development (contents of proline and lactate, activity of peroxidase) were higher in the cells of mesophyll than in the bundle sheath. At short-term NaCl (150 mM) action, the main reactions of the total adaptation syndrome were located in the cell of mesophyll. At salinity, substantial rearrangements of the isoenzyme composition of the malate dehydrogenase (MDH) system main enzymes occurred, which determined cell energization, the synthesis of reducing equivalents, maintenance of the osmotic balance, and functioning of the Hatch-Slake cycle. The changes in some intermediate concentrations and MDH-system enzyme functioning occurring under stress conditions permit a suggestion that, in maize tissues subjected to salt stress, an additional metabolic pathway related to aspartate synthesis and transport is induced.