ABSTRACT
The effects of N,N'-dicyclohexylcarbodiimide (DCCD), non-specific inhibitor of various transport systems functioning in biological membranes, on Na+-transporting P-type ATPase of the green halotolerant microalga Dunaliella maritima were studied in the experiments with vesicular plasma membranes isolated from the alga cells. The effects of DCCD on electrogenic/ion transport function of the enzyme and its ATP hydrolase activity were investigated. Electrogenic/ion transport function of the enzyme was recorded as a Na+-dependent generation of electric potential on the vesicle membranes with the help of the potential-sensitive probe oxonol VI. It was found that unlike many other ion-transporting ATPases, the Na+-ATPase of D. maritima is insensitive to DCCD. This agent did not inhibit either ATP hydrolysis catalyzed by this enzyme or its transport activity. At the same time DCCD affected the ability of the vesicle membranes to maintain electric potential generated by the D. maritima Na+-ATPase. The observed effects can be explained based on the assumption that DCCD interacts with the Na+/H+ antiporter in the plasma membrane of D. maritima.
Subject(s)
Adenosine Triphosphatases/metabolism , Cation Transport Proteins/metabolism , Cell Membrane/metabolism , Chlorophyceae/enzymology , Dicyclohexylcarbodiimide/pharmacology , Membrane Potentials/drug effects , Microalgae/enzymology , Signal Transduction/drug effects , Adenosine Triphosphate/metabolism , Biological Transport, Active/drug effects , Hydrogen-Ion Concentration , Hydrolysis/drug effects , Ion Transport/drug effects , P-type ATPases/metabolism , ProtonsABSTRACT
One of the genes of the CLC (Chloride Channel) family, SaCLCc1, from the halophyte Suaeda altissima (L.) Pall. was cloned. To investigate the function of SaCLCc1, it was expressed in the S. cerevisiae deletion mutant Δgef1::LEU2 for the only gene of the CLC family in this organism. The growth of the transformed SaCLCc1-expressing mutant Δgef1 was restored when cells were grown in Fe2+-deficient YPEG medium, in minimal synthetic media SD and SR (pH 7.0), and in rich YPD medium containing Mn2+. The complementation of the Δgef1 mutant phenotype with the SaClCc1 gene indicates the involvement of the SaClCc1 protein in the transport of Cl- ions.
Subject(s)
Amaranthaceae/genetics , Chloride Channels/genetics , Chloride Channels/metabolism , Plant Proteins/genetics , Plant Proteins/metabolism , Salt-Tolerant Plants/genetics , Amaranthaceae/growth & development , Amino Acid Sequence , Chloride Channels/chemistry , Cloning, Molecular , Mutation , Phylogeny , Plant Proteins/chemistry , Salt-Tolerant Plants/growth & developmentSubject(s)
Adenosine Triphosphatases/chemistry , Adenosine Triphosphatases/metabolism , Cell Membrane/enzymology , Cell Membrane/metabolism , Microalgae/enzymology , Multienzyme Complexes/chemistry , Multienzyme Complexes/metabolism , Adenosine Triphosphatases/classification , Enzyme Activation , Multienzyme Complexes/analysisABSTRACT
Bioregenerative life-support systems (BLSS) are studied for developing the technology for a future biological life-support system for long-term manned space missions. Ways to utilize human liquid and solid wastes to increase the closure degree of BLSS were investigated. First, urine and faeces underwent oxidation by Kudenko's physicochemical method. The products were then used for root nutrition of wheat grown by the soil-like substrate culture method. Two means of eliminating sodium chloride, introduced into the irrigation solution together with the products of urine oxidation, were investigated. The first was based on routine electrodialysis of irrigation water at the end of wheat vegetation. Dialysis eliminated about 50% of Na from the solution. This desalinization was performed for nine vegetations. The second method was new: after wheat cultivation, the irrigation solution and the solution obtained by washing the substrate containing mineral elements not absorbed by the plants were used to grow salt-tolerant Salicornia europaea L. plants (saltwort). The above-ground biomass of this plant can be used as a food, and roots can be added to the soil-like substrate. Four consecutive wheat and Salicornia vegetations were cultivated. As a result of this wheat and Salicornia cultivation process, the soil-like substrate salinization by NaCl were considerably decreased.
