Two genes of nitrate transporters SaNRT2.1 and SaNRT2.5, putative orthologs of high-affinity nitrate transporter genes AtNRT2.1 and AtNRT2.5 from Arabidopsis thaliana, were cloned from the ...euhalophyte Suaeda altissima. Phylogenetic bioinformatic analysis demonstrated that the proteins SaNRT2.1 and SaNRT2.5 exhibited higher levels of homology to the corresponding proteins from the plants of family Amaranthaceae; the similarity of amino acid sequences between proteins SaNRT2.1 and SaNRT2.5 was lower (54%). Both SaNRT2.1 and SaNRT2.5 are integral membrane proteins forming 12 transmembrane helices as predicted by topological modeling. An attempt to demonstrate nitrate transporting activity of SaNRT2.1 or SaNRT2.5 by heterologous expression of the genes in the yeast Hansenula (Ogataea) polymorpha mutant strain Δynt1 lacking the only yeast nitrate transporter was not successful. The expression patterns of SaNRT2.1 and SaNRT2.5 were studied in S. altissima plants that were grown in hydroponics under either low (0.5 mM) or high (15 mM) nitrate and salinity from 0 to 750 mM NaCl. The growth of the plants was strongly inhibited by low nitrogen supply while stimulated by NaCl; it peaked at 250 mM NaCl for high nitrate and at 500 mM NaCl for low nitrate. Under low nitrate supply, nitrate contents in S. altissima roots, leaves and stems were reduced but increased in leaves and stems as salinity in the medium increased. Potassium contents remained stable under salinity treatment from 250 to 750 mM NaCl. Quantitative real-time PCR demonstrated that without salinity, SaNRT2.1 was expressed in all organs, its expression was not influenced by nitrate supply, while SaNRT2.5 was expressed exclusively in roots—its expression rose about 10-fold under low nitrate. Salinity increased expression of both SaNRT2.1 and SaNRT2.5 under low nitrate. SaNRT2.1 peaked in roots at 500 mM NaCl with 15-fold increase; SaNRT2.5 peaked in roots at 500 mM NaCl with 150-fold increase. It is suggested that SaNRT2.5 ensures effective nitrate uptake by roots and functions as an essential high-affinity nitrate transporter to support growth of adult S. altissima plants under nitrogen deficiency.
Transgenic tobacco plants overexpressing the choline oxidase gene from
showed an increase in resistance at the level of primary and secondary biosynthesis of metabolites, removing the damage ...characteristic of salinity and stabilizing the condition of plants. We used 200 mM NaCl, which inhibits the growth of tobacco plants at all stages of development. Leaves of transgenic and wild-type (WT) plants
were used for biochemical, cytological and molecular biological analysis. However, for transgenic lines cultivated under normal conditions (without salinity), we noted juvenile characteristics, delay in flowering, and slowing down of development, including the photosynthetic apparatus. This caused changes in the amount of chlorophyll, a delay in the plastid grana development with the preservation of prolamellar bodies. It also caused changes in the amount of sugars and indirectly downstream processes. A significant change in the activity of antioxidant enzymes and a change in metabolism is probably compensated by the regulation of a number of genes, the expression level of which was also changed. Thus, the tolerance of transgenic tobacco plants to salinity, which manifested itself as a result of the constitutive expression of
, demonstrates an advantage over WT plants, but in the absence of salinity, transgenic plants did not have such advantages due to juvenilization.
A promising spiropyridobenzopyran–indoline molecular platform for the development of ionochromic systems with a high potential for metal cation chemosensor applications is developed. Evidence for ...this conclusion is provided the established characteristics and properties of 6-bromo-substituted spiropyridobenzopyran–indoline, including ionochromism accompanied by a chromogenic effect in the form of a red shift that reaches 200 nm. The obtained Zn(II), Ni(II), Cu(II), Co(II), and Cd(II) complexes are characterized by a high stability with constants of 10
5.6
–10
8.6
and 10
5.0
–10
6.9
for the first and second steps, respectively. The possibilities to obtain selective sensors are associated with the fluorescence detected in the Zn(II) and Cd(II) complexes only. The photostability of the studied complexes, on the one hand, and the high spectral contrast of complex formation of the dynamic 6-bromo-substituted spiropyridobenzopyran–indoline systems on the other, open up the possibility of using chemosensors based on these molecular platforms in the naked-eye colorimetric mode.
Indoline spiropyran containing an σ-acceptor chlorine atom in 6′ position of the 2
H
-chromene part of the molecule was synthesized and studied. The use of 1,2,3,3-tetramethyl-3
H
-indolium ...perchlorate as a starting compound made it possible to achieve higher product yields as compared to previous studies. The molecular structure of the compound was established by single crystal X-ray diffraction analysis. The features of the crystal structure and intermolecular interactions were investigated using CrystalExplorer17 software package. The photochromic behavior in acetonitrile solution was studied for the first time. It was found that the merocyanine form of spiropyran is characterized by an absorption maximum at 592 nm, which is 37 nm closer to the range of the “biological window” in comparison with the nitro-substituted analog.
The reaction of fluorescein-substituted 2-hydroxybenzaldehyde with 3
H
-indolium perchlorate has led to the formation of 1,3-dihydrospiroindole-2,2′-chromene bearing a fluorescein fragment at ...position 8 of chromene. In a solution, the obtained compound has existed in the cyclic form and has exhibited photochromic properties. Adding transition metal perchlorates to the spiropyran solution has led to intense coloration due to the complex formation. Zinc and cadmium complexes of the spiropyran have exhibited red fluorescence and negative photochromism.
New indoline spiropyrans containing chlorine and bromine atoms in position 5 of the indoline moiety of the molecule as a substituent were synthesized and studied. The structures of the synthesized ...compounds were confirmed by NMR and IR spectroscopy. The molecular structure of the chlorine-substituted derivative was determined by X-ray diffraction analysis, and intermolecular interactions in the crystal were studied using the CrystalExplorer21.5 software package. The spectral kinetic studies revealed photochromic properties of novel spiropyrans in an acetonitrile solution. The photoelectrochemical characteristics of dye-sensitized solar cells (DSSC) made from the synthesized compounds before and after UV irradiation were studied in comparison.
As a result of an analysis of published works, a database on paleotemperatures in the Arctic and Subarctic regions based on marine invertebrate skeletons, marine palynomorphs, dinosaur teeth, ...analysis of the ability of reptiles to lay eggs at low temperatures, terrestrial floral assemblages (CLAMP-analysis), the presence of coal interbeds in continental deposits within the Arctic region, and on membrane lipids of glycerol and dialkylglycerol tetraether in marine sediments and glendonite was assembled. Based on the obtained data, a paleotemperature curve for the Cretaceous–Cenozoic stage of geological history of the Arctic region was constructed. The general trends of this curve are in consistent with the global paleotemperature curve (Scotese, 2015) (with the exception of the cooling period in the Tortonian due to local factors). In total, 16 climatic cycles in the climatic history of the Arctic, including 16 climatic minima (including the glaciation in the Northern Hemisphere) and 15 climatic maxima have been established.
—The lithological and geochemical characteristics of the Meso-Cenozoic interval of the Leskinskaya borehole section (the mouth of the Yenisei River) and its paleogeographic and paleoclimatic ...characteristics are given.
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•Spiropyran complexes undergo negative photochromism.•Negative photochromism is quantitatively characterized by the photokinetic method.•Cd2+, Mn2+ and Zn2+ complexes are effective ...photochromic systems.
8-(1,3-Benzoxazol-2-yl) substituted spirobenzopyrans 1A appear as a chromogenic system susceptible of switching between positive and negative photochromism under complexation with metal ions. The thermal and photochemical reactions accompanying metal ion-induced transformation of spiropyrans 1A to the complexes formed by their photoinduced merocyanine isomers 1B were investigated. In the dark, the colorless spiropyrans interact with Mn2+, Cd2+ and Zn2+ transition metal ions to yield deeply colored 1:1 complexes possessing fluorescence, while Co2+, Ni2+, Cu2+ ions prefer to form non-fluorescent complexes with two merocyanines. Under irradiation with visible light solutions of the merocyanine-metal complexes undergo photobleaching. This effect was quantified using photokinetic method.
New benzoxazolyl-substituted spiroindoline-benzopyrans with electron-withdrawing groups in the indoline fragment were obtained. These compounds exhibit positive P- and T-type photochromism. ...Structural correlations of the spectrokinetic properties depending on the variation of substituents in the indoline part of the spiropyran molecules were established. Electronwithdrawing groups were found to cause a bathochromic shift of the long-wavelength absorption maxima of the merocyanine isomers as compared to the unsubstituted spiropyran and decrease their lifetime. Conversely, an introduction of electron-donating groups results in a hypso chromic shift of the absorption maxima and an increase in the lifetime of the colored isomers of spiropyrans. Electron-withdrawing substituents at the position 5 of the indoline fragment cause the increase of the colorability of the spiropyrans.
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