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1.
Gradual reduction of the amount of cells constituting postmitotic tissues appears to be one of the most reliable mechanisms
realizing the program of aging. A signal starting the program of cellular death (PCD) in a part of cellular population can
be an excess of a threshold level of PCD inductor production as a result of stochastic processes. Speed of aging is regulated
by the proportion of average PCD inductor production, variability of this rate and the size of a threshold level of the PCD
induction. The developed model allows to study the progress of these processes and their modulation by antioxidants in silico. 相似文献
2.
T. F. Ibragimov M. G. Levkovich V. A. Saprykina Kh. M. Shakhidoyatov 《Chemistry of Natural Compounds》2010,46(5):767-770
N-Chloroacetylcytisine was synthesized by acylation of (–)-cytisine. Stable Z- and E-conformers with respect to rotational isomerism around the N-12–CO bond were found in PMR spectra at room temperature. The
point at which PMR resonances of the Z- and E-conformers coalesced upon heating was measured. The transition barrier between the conformers was estimated. 相似文献
3.
Background
The compounds 1,4-napthoquinone (1,4-NQ), bis-(2,4-dinitrophenyl)sulfide (2,4-DNPS), 4-nitrobenzothiadiazole (4-NBT), 3-dimethylaminopropiophenone (3-DAP) and menadione (MD) were tested for antimalarial activity against both chloroquine (CQ)-sensitive (D6) and chloroquine (CQ)-resistant (W2) strains of Plasmodium falciparum through an in vitro assay and also for analysis of non-covalent interactions with P. falciparum thioredoxin reductase (PfTrxR) through in silico docking studies.Results
The inhibitors of PfTrxR namely, 1,4-NQ, 4-NBT and MD displayed significant antimalarial activity with IC50 values of?<?20 μM and toxicity against 3T3 cell line. 2,4-DNPS was only moderately active. In silico docking analysis of these compounds with PfTrxR revealed that 2,4-DNPS, 4-NBT and MD interact non-covalently with the intersubunit region of the enzyme.Conclusions
In this study, tools for the identification of PfTrxR inhibitors using phenotyphic screening and docking studies have been validated for their potential use for antimalarial drug discovery project.4.
A. V. Lezov G. E. Polushina A. A. Lezov P. S. Vlasov N. S. Domnina 《Polymer Science Series A》2011,53(2):93-101
The hydrodynamic and conformational properties of molecules of poly(N,N-diallyl-N,N-dimethylammonium chloride) and N,N-diallyl-N,N-dimethylammonium chloride-maleic acid copolymers of different compositions in solutions with various ionic-strength and pH
values, as well as of the polyelectrolyte complex based on the copolymer with dodecyl sulfate anions in chloroform, are studied.
For poly(N,N-diallyl-N,N-dimethylammonium chloride) molecules in a 1 M NaCl solution, the Kuhn segment length and the hydrodynamic diameter of the
chain are estimated as A = 3.9 nm and d = 0.48 nm, respectively. In acidic solutions with pH 3.5, the copolymers demonstrate behavior typical for polyelectrolytes.
In an alkaline solution with pH 13, when 1 M NaCl is added to the solution of the copolymer containing 29 mol % maleic acid
units, there is an antipolyelectrolyte effect that manifests itself as an increase in the intrinsic viscosity of the copolymer
and in the hydrodynamic radius of its molecules. It is found that an increase in the fraction of maleic acid units in the
copolymer from 12 to 42 mol % brings about a reduction in the equilibrium rigidity of its macromolecules from 4.1 to 2.2 nm.
The equilibrium rigidity of polyelectrolyte-complex molecules is higher than that of initial copolymer molecules owing to
steric interactions arising between the aliphatic chains of dodecyl sulfate anions. In an electric field, the molecules of
the complex are oriented owing to the induced dipole moment resulting from the displacement of dodecyl sulfate anions along
the chain contour. 相似文献
5.
A. I. Vorob’eva M. S. Babaev L. V. Spirikhin N. M. Shishlov S. V. Kolesov 《Russian Journal of Applied Chemistry》2016,89(1):160-164
A copolymer of N,N-diallyl-N,N-dimethylammonium chloride with maleic acid of constant composition was prepared under the conditions of radical initiation. The possibility of the functionalization of the copolymer with drugs containing amino groups by polymer-analogous transformations was examined. Conditions were found for preparing conjugates of the copolymer with isoniazid. The structures and the quantitative compositions of the conjugates were determined by 13С NMR spectroscopy, and the possibility of preparing conjugates with controlled drug content was demonstrated. 相似文献
6.
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8.
Eberhard Reimann Rainer Hertel Jürgen Krauss 《Monatshefte für Chemie / Chemical Monthly》2008,139(6):673-684
Alkylation of Reissert compounds derived from 3-methylisoquinolines with several 2-cyanobenzylbromides followed by hydrolytic cleavage provided the corresponding 1-benzyl-3-methylisoquinolines. Treatment of the latter with methylmagnesiumiodide caused cyclization to the title compounds rather than formation of 2-acetylbenzylisoquinolines. 相似文献
9.
V. Guerrero-Torres M. Rios-Lozano J. A. Badillo-Corona I. Chairez C. Garibay-Orijel 《Applied biochemistry and biotechnology》2016,179(8):1418-1434
The aim of this study was to design a robust parameter identification algorithm to characterize the effect of gene deletion on Escherichia coli (E. coli) MG1655. Two genes (pta and poxB) in the competitive pathways were deleted from this microorganism to inhibit pyruvate consumption. This condition deviated the E. coli metabolism toward the Krebs cycle. As a consequence, the biomass, substrate (glucose), lactic, and acetate acids as well as ethanol concentrations were modified. A hybrid model was proposed to consider the effect of gene deletion on the metabolism of E. coli. The model parameters were estimated by the application of a least mean square method based on the instrument variable technique. To evaluate the parametric identifier method, a set of robust exact differentiators, based on the super-twisting algorithm, was implemented. The hybrid model was successfully characterized by the parameters obtained from experimental information of E. coli MG1655. The significant difference between parameters obtained with wild-type strain and the modified (with deleted genes) justifies the application of the parametric identification algorithm. This characterization can be used to optimize the production of different byproducts of commercial interest. 相似文献
10.
O. G. Strukov V. B. Kondrat’ev Z. V. Vlasova V. A. Petrunin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2017,91(1):100-105
Conformers of the biologically active compounds CH3P(O)(OR)(SCH2CH2NR 2 ′ ), where (I) R = i-C4H9, R′ = C2H5 and (II) R = C2H5, R′ = i-C3H7, are calculated within the AM1 level of theory. The elongated and twisted forms with maximum and minimum distances between a nitrogen atom and those of a phosphorus tetrahedron, respectively, and bearing a syn and anti oriented alkoxy group relative to a phosphoryl oxygen, are studied. It is found that the differences between the energy, electronic, and geometric parameters of these forms are apparent in differences between their properties, e.g., the ability to participate in complexation and protonation, reactions that to some extent simulate the interaction between a substance and a biological object. 相似文献
11.
D. T. Asilbekova F. M. Tursunkhodzhaeva A. M. Nigmatullaev 《Chemistry of Natural Compounds》2009,45(3):322-324
The composition of lipids from the aerial parts of two species of halophytes from the family Chenopodiaceae, Halostachys caspica C. A. Mey. and Halocharis hispida Bge. was determined. Neutral lipids (NL, 62.1 and 54.2%, respectively) dominated the total lipids (TL) of these plants. More
than a third of the NL were esters of aliphatic alcohols and phytosterols (FAE). Fatty acids 16:0, 18:1, and 18:2 dominated
the acids of FAE; 16:0, 18:1, and 18:3, the phospholipids. The principal fatty acids of glycolipids were unsaturated acids
(68.3 and 75.1%) with linolenic acid dominating (44.9 and 43.5%).
Presented at the 7th International Symposium on the Chemistry of Natural Compounds, Tashkent, October 16–18, 2007.
Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 276–278, May–June, 2009. 相似文献
12.
Background
Adenylation of nicotinate mononucleotide to nicotinate adenine dinucleotide is the penultimate step in NAD+ synthesis. In Escherichia coli, the enzyme nicotinate mononucleotide adenylyltransferase is encoded by the nadD gene. We have earlier made an initial characterization in vivo of two mutant enzymes, NadD72 and NadD74. Strains with either mutation have decreased intracellular levels of NAD+, especially for one of the alleles, nadD72. 相似文献13.
U. S. Makhmudov Sh. B. Rakhimov B. Tashkhodzhaev M. G. Levkovich V. I. Vinogradova 《Chemistry of Natural Compounds》2008,44(2):208-212
The molecular structures of N-(o-and p-hydroxybenzyl)cytisine were investigated by NMR spectroscopy, x-ray structure analysis, and molecular modeling. It was found
that NMR resonances of the OH and aromatic protons in N-(o-hydroxybenzyl)cytisine were doubled because of the presence of two conformers in solution.
__________
Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 165–168, March–April, 2008. 相似文献
14.
A number of (Z)-N,N-dialkyl- and (Z)-N-acyl-N-alkyl-O-methylnicotinamide oximes was synthesized. Their configuration was confirmed by the NOESY experiment. Evaluation of fungicidal
activity of compounds obtained was performed. 相似文献
15.
Sunisa Suwancharoen Orawan Chonvanich Sophon Roengsumran Surachai Pornpakakul 《Chemistry of Natural Compounds》2012,48(4):583-586
A new seco-kaurane type diterpenoid, ent-3,4-seco-17-oxo-kaur-4(19),15(16)-dien-3-oic acid, and a known compound, ent-3,4-seco-kaur-4(19),16(17)-dien-3-oic acid, were isolated from the stem bark of Croton oblongifolius. The structures of these compounds were established on the basis of spectroscopic data. 相似文献
16.
P. A. Storozhenko Z. V. Belyakova O. A. Starikova V. M. Nosova T. I. Shulyat’eva A. S. Frenkel’ M. V. Pecherskii 《Russian Journal of General Chemistry》2008,78(5):892-897
N-Metallation of bromoanilines with ethylmagnesium bromide followed by a reaction with trimethylchlorosilane provided N-mono and N-bis(trimethylsilyl)bromoanilines depending on the structure of substrate. The metallation of bissilylated bromoanilines with butyllithium permitted the introduction of a trimethylsilyl substituent in the aromatic ring. Previously unknown 2-bromo-N,N-bis(trimethylsilyl)aniline, 2,6-dibromo-N-trimethylsilylaniline, 2,6-dibromo-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilylaniline, 2-bromo-6-trimethylsilyl-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilyl-N-trimethylsilylaniline, 2,4,6-tribromo-N-trimethylsilylaniline, and 2,4,6-tribromo-N,N-bis(trimethylsilyl)aniline were prepared. The structures of the compounds obtained were established by the chromato-mass spectrometry and 1H, 13C, and 29Si NMR spectroscopy. 相似文献
17.
E. A. Dikusar V. I. Potkin D. A. Rudakov T. D. Zvereva S. K. Petkevich M. M. Ogorodnikova A. P. Yuvchenko M. P. Bei 《Russian Journal of General Chemistry》2012,82(3):413-416
A method of preparative synthesis of o(m)-carborane-containing azomethines via the condensation of o(m)-carboranyl-C-methylene-4-formylbenzoates with aliphatic, cycloaliphatic, and aromatic amines was developed. 相似文献
18.
In neutral zinc the 4p
2 configuration lies above the 3d
104s ionization limit and its levels become perturbers in the continuum. Lines have been identified in the Zn I spectrum for the
multiplet, whereas no lines have been found for transitions to 4p
2 1
D or 1
S. In this paper, cross sections for photoionization from 4s4p levels are reported that reveal the positions and widths of the 4p
2 resonances. Calculations were performed using the multiconfiguration Hartree-Fock (MCHF) and B-spline R-matrix (BSR) method. Results from Breit–Pauli calculations that ignore the background continua are also presented. Included
in the latter are energies for the levels and transition data (transition energies, line strengths, f-values, and A-rates) for all E1 transitions between these
levels. Transition energies and the agreement in the length and velocity values, particularly for allowed transitions, indicate
the accuracy of the computational model. Line widths are compared with other estimates.
Contribution to the Serafin Fraga Memorial Issue. 相似文献
19.
V. I. Rakhlin R. G. Mirskov T. A. Podgorbunskaya M. G. Voronkov 《Russian Journal of General Chemistry》2007,77(9):1512-1518
The review is devoted to N-halohexamethyldisilazanes, perspective but scantily studied halogenating agents. Methods of preparation, physiochemical characteristics, and synthetic potential are considered. Mechanisms of a number of reactions are presented. 相似文献
20.
(S)-Asparagine and (S)-glutamine ortho-carboranyl derivatives with free amino and carboxy groups in the α-position were synthesized. By an example of N γ-(1,2-dicarba-closo-dodecarboran-3-yl)-(S)-glutamine it was demonstrated that the developed synthetic approach carboranyl derivatives of amino acids allowed the preparation of optically pure isomers. 相似文献