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191.
A new reactive graft copolymer, poly(tetramthylene glycol) - graft-w-propyl sodiumsulfonate-poly(ethylene glycol) (PTMG-g-PEG-CH_2CH_2CH_2SO_3~-Na~+), was synthesizedby the cationic polymerization of a-w-bifunctional PEG macromonomer (O?CH_2—PEG——CH_2 CH_2 CH_2 SO_3 Na) and THF. The obtained copolymer exhibits the expected structureas indicated by the result of characterization. Two amino acids (L-arginine, L-tyrosine)were covalently attached to the copolymer after converting the sulfonate group to sulfonylchloride. So the new reactive graft copolymer (PTMG-g-PEG-CH_2CH_2CH_2SO_3~-Na~+) isexpected to be very useful in attachment of potentially bioactive moieties to polymer viaa hydrophilic PEG spacer. 相似文献
192.
F. Schaller W. Schwarz H.-D. Hausen K. W. Klinkhammer J. Weidlein 《无机化学与普通化学杂志》1997,623(9):1455-1466
Base-free Tris(trimethylsilyl)methyl Derivatives of Lithium, Aluminium, Gallium, and Indium Base-free LiR* (R*=-C(SiMe3)3) has been prepared from R*Cl and Li-metal in toluene at 85?90°C and used to synthesize the metallanes R*MMe2 with M = Al, Ga and In, respectively. The NMR (1H, 13C, 29Si) and the vibrational spectra of these trisyl compounds have been discussed. AlCl3 and LiR*(ratio 1 : 1) forms the metallate metallate Li[R*AlCl3]. The triclinic unit cell (space group P1 ) consists of a centrosymmetric assoziate, formed by four Li[R*AlCl3]- units with Al? Cl…?Li bridges, two pairs of Li-atoms differing in their chlorine-coordination and two disordered toluene molecules, inserted in the crystal lattice (R1wR2 =0,0444/0,1072). The reaction of GaCl3 with LiR* (I :1) gives the unusual sesquichloride (R*Ga(Cl1,33)Me0,67)3 in moderate yield. The X-ray structure determination shows a Ga3Cl3-skeleton with chairconformation and disordered, terminal gallium ligands (R1/wR2= 0,0646/0,2270). 相似文献
193.
Polyol Metal Complexes. 27. Bis-Diolato Antimonates(III ) with Guanosine as the Diol The complex anions of K3[SbIII(Guo1,2′,3′H?3)2] · 10 H2O ( 1 ) and [Co(NH3)6][SbIII(Guo1,2′,3′H?3)2] · 9 H2O ( 2 ) are four-coordinate homoleptic bis(diolato)antimonate(III ) species. The guanosine trianions act as carbohydrate ligands through their cis-furanoidic ribosyl moiety, thus forming no nucleobase–metal bonds. 相似文献
194.
An electrochemical biosensor for the specific detection of short DNA sequences from the E. coli pathogen is described. This hybridization device relies on the immobilization of a 25-mer oligonucleotide probe, from the E. coli lacZ gene, onto a screen-printed carbon electrode. Chronopotentiometric detection of the Co(bpy)3+3 indicator is used for monitoring the hybridization event. Numerous variables of the assay protocol, including those of the probe immobilization step, the hybridization event, and the indicator association/detection, are characterized and optimized. Hybridization times of 2- and 30-min are sufficient for detecting 300- and 50 ng/mL, respectively, of the E. coli DNA target. Applicability to analysis of untreated environmental water samples is illustrated. Such single-use electrochemical sensors hold great promise for decentralized environmental and food testing for the E. coli pathogen. 相似文献
195.
Silvie Rimpelov Michal Kol Hynek Strnad Tom Ruml Libor Vítek Helena Gbelcov 《Molecules (Basel, Switzerland)》2021,26(12)
Statins have been widely used for the treatment of hypercholesterolemia due to their ability to inhibit HMG-CoA reductase, the rate-limiting enzyme of de novo cholesterol synthesis, via the so-called mevalonate pathway. However, their inhibitory action also causes depletion of downstream intermediates of the pathway, resulting in the pleiotropic effects of statins, including the beneficial impact in the treatment of cancer. In our study, we compared the effect of all eight existing statins on the expression of genes, the products of which are implicated in cancer inhibition and suggested the molecular mechanisms of their action in epigenetic and posttranslational regulation, and in cell-cycle arrest, death, migration, or invasion of the cancer cells. 相似文献
196.
Alexandr Zalessky Yuriy Fedotov Elizaveta Yashkina Viktor Nadtochenko Andreyan N. Osipov 《Molecules (Basel, Switzerland)》2021,26(13)
To assess the prospects for using intense femtosecond laser radiation in biomedicine, it is necessary to understand the mechanisms of its action on biological macromolecules, especially on the informational macromolecule—DNA. The aim of this work was to study the immunocytochemical localization of DNA repair protein foci (XRCC1 and γH2AX) induced by tightly focused femtosecond laser radiation in human cancer A549 cells. The results showed that no XRCC1 or γH2AX foci tracks were observed 30 min after cell irradiation with femtosecond pulses of 1011 W∙cm−2 peak power density. An increase in the pulse power density to 2 × 1011 W∙cm−2 led to the formation of linear tracks consisting both of XRCC1 and γH2AX protein foci localized in the places where the laser beam passed through the cell nuclei. A further increase in the pulse power density to 4 × 1011 W∙cm−2 led to the appearance of nuclei with total immunocytochemical staining for XRCC1 and γH2AX on the path of the laser beam. Thus, femtosecond laser radiation can be considered as a tool for local ionization of biological material, and this ionization will lead to similar effects obtained using ionizing radiation. 相似文献
197.
Silvija Mara
i Petra Grb
i Suresh Shammugam Marijana Radi Stojkovi Kreimir Paveli Mirela Sedi Sandra Kraljevi Paveli Silvana Rai-Mali 《Molecules (Basel, Switzerland)》2021,26(22)
The novel 1,2,3-triazolyl-appended N- and O-heterocycles containing amidine 4–11 and amidoxime 12–22 moiety were prepared and evaluated for their antiproliferative activities in vitro. Among the series of amidine-substituted heterocycles, aromatic diamidine 5 and coumarine amidine 11 had the most potent growth-inhibitory effect on cervical carcinoma (HeLa), hepatocellular carcinoma (HepG2) and colorectal adenocarcinoma (SW620), with IC50 values in the nM range. Although compound 5 was toxic to non-tumor HFF cells, compound 11 showed certain selectivity. From the amidoxime series, quinoline amidoximes 18 and 20 showed antiproliferative effects on lung adenocarcinoma (A549), HeLa and SW620 cells emphasizing compound 20 that exhibited no cytostatic effect on normal HFF fibroblasts. Results of CD titrations and thermal melting experiments indicated that compounds 5 and 10 most likely bind inside the minor groove of AT-DNA and intercalate into AU-RNA. Compounds 6, 9 and 11 bind to AT-DNA with mixed binding mode, most probably minor groove binding accompanied with aggregate binding along the DNA backbone. 相似文献
198.
Yang Xin Amir Ardalan Zargariantabrizi Guido Grundmeier Adrian Keller 《Molecules (Basel, Switzerland)》2021,26(16)
DNA origami nanostructures (DONs) are promising substrates for the single-molecule investigation of biomolecular reactions and dynamics by in situ atomic force microscopy (AFM). For this, they are typically immobilized on mica substrates by adding millimolar concentrations of Mg2+ ions to the sample solution, which enable the adsorption of the negatively charged DONs at the like-charged mica surface. These non-physiological Mg2+ concentrations, however, present a serious limitation in such experiments as they may interfere with the reactions and processes under investigation. Therefore, we here evaluate three approaches to efficiently immobilize DONs at mica surfaces under essentially Mg2+-free conditions. These approaches rely on the pre-adsorption of different multivalent cations, i.e., Ni2+, poly-l-lysine (PLL), and spermidine (Spdn). DON adsorption is studied in phosphate-buffered saline (PBS) and pure water. In general, Ni2+ shows the worst performance with heavily deformed DONs. For 2D DON triangles, adsorption at PLL- and in particular Spdn-modified mica may outperform even Mg2+-mediated adsorption in terms of surface coverage, depending on the employed solution. For 3D six-helix bundles, less pronounced differences between the individual strategies are observed. Our results provide some general guidance for the immobilization of DONs at mica surfaces under Mg2+-free conditions and may aid future in situ AFM studies. 相似文献
199.
200.
Cyclodextrin-Containing Polymers for Gene Delivery 总被引:2,自引:0,他引:2
Mark E. Davis Nathalie C. Bellocq 《Journal of inclusion phenomena and macrocyclic chemistry》2002,44(1-4):17-22
Cyclodextrin-containing polymers are now being explored as vehicles for delivering nucleic acids into cells. The structures of the cyclodextrin-containing polycations affect the nucleic acid delivery efficiencies and their toxicities. Of interest is the fact that the cyclodextrin-containing polymers reveal lower toxicities than polymers that lack the cyclodextrins. The cyclodextrins endow the nucleic acid delivery vehicles with the ability to be modified by compounds that form inclusion complexes with the cyclodextrins, and these modifications can be performed without disruption of the polymer-nucleic acid interactions. Thus, cyclodextrin-containing polymers provide unique properties for gene delivery. 相似文献