The nanocrystalline phosphor NaGd
0.7
Eu
0.3
F
4
with the most intensive luminescence among NaGd
1–
x
Eu
x
F
4
(
x
= 0–1) compounds was obtained by hydrothermal synthesis. The unit cell parameters ...and nanoparticle size were determined. The cytotoxicity, luminescent, and magnetic properties were characterized.
The present study evaluates the cytotoxicity of a previously synthesized conjugate of betulinic acid (BA) with the penetrating cation F16 on breast adenocarcinoma (MCF-7) and human fibroblast (HF) ...cell lines, and also shows the mechanism underlying its membranotropic action. It was confirmed that the conjugate exhibits higher cytotoxicity compared to native BA at low doses also blocking the proliferation of both cell lines and causing cell cycle arrest in the G
/G
phase. We show that the conjugate indeed has a high potential for accumulation in mitochondria, being visualized in these organelles, which is most pronounced in cancer cells. The effect of the conjugate was observed to be accompanied by ROS hyperproduction in both cancerous and healthy cells, despite the lower base level of ROS in the latter. Along with this, using artificial liposomes, we determined that the conjugate is able to influence the phase state of lipid membranes, make them more fluid, and induce nonspecific permeabilization contributing to the overall cytotoxicity of the tested agent. We conclude that the studied BA-F16 conjugate does not have significant selective cytotoxicity, at least against the studied breast cancer cell line MCF-7.
The combination of the same organic tecton 1, a meta-pyridyl appended tetramercaptotetrathiacalix4arene in 1,3-alternate conformation offering four pyridyl units and eight thioether groups, with ...three silver salts AgX (X = BF4(-), NO3(-) and SbF6(-)) leads, under identical conditions (concentration, temperature and solvent system), to the formation of different silver coordination networks. Both the connectivity and the dimensionality of the three silver coordination networks depend on the nature of the anion used as a counter ion. Whereas the weakly coordinating BF4(-) anion does not participate in the formation of the non-tubular 1D coordination network, the coordinating NO3(-) anion is bound to the metal cation and this leads to the formation of a tubular 1D silver coordination network. In both cases, the eight S atoms of the tecton 1 do not take part in the binding of the cation. In marked contrast, when the SbF6(-) anion is used as a counter ion, the organic tecton 1 behaves as a tetrakismonodentate through its four meta-pyridyl moieties and as a bischelating unit of the SCCS type leading thus to the formation of a porous 3D diamondoid-type network.
The present studies were conducted to address cellular mechanisms responsible for regulating steroidogenic acute regulatory
protein (StAR) expression and progesterone synthesis at maturational stages ...corresponding to both the time of hen follicle
selection, as well as before and after the LH surge in preovulatory follicle granulosa cells. A recently published report
has established that mitogen-activated protein (MAP) kinase signaling induced by transforming growth factor α (TGFα) treatment
blocks FSH-induced differentiation and StAR expression in cultured hen granulosa cells, whereas inhibitors of MAP kinase signaling
enhance FSH-induced differentiation. The present in vitro studies demonstrate that in addition to MAP kinase signaling, activation
of protein kinase C (PKC) blocks both FSH-induced StAR expression and the initiation of progesterone production in prehierarchal
follicle granulosa cells, whereas the pharmacologic inhibitor of PKC, GF109203X, potentiates FSH-induced StAR expression and,
as a consequence, the initiation of progesterone synthesis. Moreover, we demonstrate in granulosa cells collected from preovulatory
follicles that although an acute increase in progesterone production in response to LH treatment requires rapid transcription
and translation of StAR, the magnitude of progesterone production is rate-limited by one or more factors other than StAR (e.g.,
the P450 cholesterol side-chain enzyme). Finally, the rapid turnover of StAR protein, such as occurs following the withdrawal
of LH, provides an additional mechanism for the tight regulation of progesterone production that occurs during the hen ovulatory
cycle, and explains the rapid loss of steroidogenesis in the postovulatory follicle. In summary, data reported herein support
the proposal that paracrine/autocrine factors (including but not necessarily limited to TGFα) prevent premature expression
of StAR in prehierarchal follicle granulosa cells by more than one receptor-mediated signaling pathway. Furthermore, subsequent
to follicle selection into the preovulatory hierarchy, StAR transcription and translation is necessary but not sufficient
for the full potentiation of the preovulatory surge of serum progesterone.
A series of thiacalix4arene derivatives blocked in the 1,3-alternate conformation and bearing four carboxylic acids have been designed and synthesized. These compounds, owing to the H-bond donor (OH ...moiety) and acceptor (C&z.dbd; O group) nature of the carboxylic acid moieties, behave as self-complementary tectons and lead to the formation of tubular 1D H-bonded networks in the crystalline phase. Upon deprotonation of the self-complementary neutral compounds, i.e. transformation of carboxylic acid moieties into carboxylates, anionic tectons are generated. Due to their propensity to form H-bonded networks in the presence of a dicationic H-bond donor tecton of the cyclic bis-amidinium type, designed to behave as a molecular staple interconnecting two carboxylates moieties, 1- and 2-D H-bonded networks are formed under self-assembly conditions.
Relevance.
The main source of the natural pigment betanin is table beet, known for its medicinal and antioxidant properties, earliness and long shelf life, rich in bioactive compounds, minerals and ...vitamins. This research was induced by the lack of information required by breeders to increase betanin content in beet. Metabolite profiling is an effective way to assess the interplay between individual metabolites and betanin content in table beet.
Materials and methods
. The material was selected from the the N.I. Vavilov Institute of plant industry (VIR) collection. Biochemical analysis was based on VIR’s guidelines, and metabolite profiling on gas chromatography, coupled with mass spectrometry.
Results.
17 free amino acids were found in the beet root extract. The greatest number of positive correlations with other amino acids (r˃0.72) was found in tyrosine, alanine and phenylalanine. A significant (r = –0.66) negative correlation was observed between betanin and succinic acid, credibly associated with betalamic acid. Sucrose predominated among carbohydrates (95%). Sucrose and maltose showed a weak positive correlation with betanin. Unsaturated oleic and saturated palmitic acids dominated among fatty acids (52% and 20% of total fatty acids, respectively). Earlier-ripening and cold-resistant table beet accessions showed a predominance of unsaturated fatty acids and lower betanin content. The disclosed interactions are important for betanin-rich red beet breeding.
Three p-H-thiacalix4arene pyridyl appended coordinating tectons (2-4) in a 1,3-alternate conformation have been prepared and structurally characterised in the solid state. These compounds are ...positional isomers differing only by the position of the nitrogen atom on the pyridyl ring. Their combinations with HgCl2 lead to the formation of 1- and 2-D neutral mercury coordination networks. Whereas for tecton 2 (ortho isomer) a 2D architecture resulting from the bridging of consecutive tectons by the mononuclear HgCl2 unit is obtained, for tecton 3 (meta isomer) again a 2D network is formed. However, in that case, the interconnection of consecutive organic tectons 3 takes place through a binuclear Hg2Cl4 species. Finally, in the case of tecton 4 (para position), a 1D ribbon type double chain arrangement resulting from the bridging of consecutive tectons by trinuclear Hg3Cl6 units followed by the interconnection of two chains through the fusion of the trinuclear centres into a hexanuclear node is observed.
A series of four new Dy12 dodecanuclear clusters based on azobenzene derivative ligands of salicylic acid (L1–L4) has been synthesized and characterized in the crystalline phase using X-ray ...diffraction on single crystal and powder, IR spectroscopy, elemental analysis, and DSC–TGA methods. It was revealed that all obtained clusters exhibit the formation of the similar metallic cluster nodes, as vertex-sharing heterocubanes, obtained from four Dy3+ cations, three bridging hydroxyl groups, and O atoms from the salicylic ligands. The coordination geometry around the Dy(III) centers has been carefully analyzed. Whereas Dy12-L1 and Dy12-L2 with L1 and L2 containing Me and OMe groups in para positions of the phenyl rings, respectively, form similar porous 3D diamond-like molecular networks due to CH−π interactions, for Dy12-L3 with L3 bearing NO2-electron-withdrawing group, the generation of 2D molecular grids assembled by π–π staking is observed, and for Dy12-L4 with L4 bearing phenyl substituent, 3D hexagonal channels have been generated. The complexes Dy12-L1, Dy12-L2, and Dy12-L3 exhibit a zero-field slow magnetic relaxation effect. After UV irradiation of Dy12-L1, a decrease of the magnetic anisotropy energy barrier displaying the possibility of control over magnetic properties by the external stimulus has been observed.
The interest in functional supramolecular systems for the design of innovative materials and technologies, able to fundamentally change the world, is growing at a high pace. The huge array of ...publications that appeared in recent years in the global literature calls for systematization of the structural trends inherent in the formation of these systems revealed at different molecular platforms and practically useful properties they exhibit. The attention is concentrated on the topics related to functional supramolecular systems that are actively explored in institutes and universities of Russia in the last 10–15 years, such as the chemistry of host–guest complexes, crystal engineering, self-assembly and self-organization in solutions and at interfaces, biomimetics and molecular machines and devices.
The bibliography includes 1714 references.
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