- Highly selective turn-on red fluorescence probes for visualization of the G-quadruplexes DNA in living cells
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Studies on small molecule fluorescent probes for detecting G-quadruplexes DNA have bring about an extensive attention in recent years. In this paper, we designed and synthesized three benzothiazole derivatives named 2a-2c under moderate reaction conditions and investigated their interactions with DNA (single-stranded, duplex, i-motif and G-quadruplex) and distribution in living cell. Three compounds present a large Stokes shift (~90 nm) and a weak red fluorescence emission, and they exhibit a good selectivity and sensitive turn-on fluorescence response for the promoter G-quadruplex DNA (bcl-2, c-myc and c-kit 2) and mitochondria G-quadruplex (KSS). The affinity of 2a and 2b with N-alkyl side chain group to DNA is stronger than that of 2c with an anion group, therefore, they also increase the stability of the G-quadruplex structure. 2b induces the conformational change of both bcl-2 and KSS G-quadruplexes, while all compounds induce the folding of bcl-2 from the coiled structure to the hybrid G-qrudruplex. Three compounds interact with the G-quadruplex DNA mainly by end-stacking mode. Furthermore, MTT assays and confocal fluorescence images show that these compounds can enter the living HepG2 cells with low cytotoxicity. 2a-2c are mainly located in the mitochondrion and interacted with mitochondria G-quadruplex DNA, while only weak fluorescence can be found in cell nucleus. In a word, 2a-2c can be implied in image of G-quadruplex DNA in living cells.
- Kang, Yongqiang,Wei, Chunying
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- Stability and Self-Association of styryl hemicyanine dyes in water studied by 1H NMR spectroscopy
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The stability in water of five styryl hemicyanine dyes containing benzoxazole, benzothiazole, benzoselenazole and oxazolopyridne rings with different substituents at different pH values has been investigated. All compounds are stable at acidic and neutral pH, however, at basic pH the oxazole dyes undergo a ring opening reaction. The stability at basic pH is increased by substituting the benzooxazolium with oxazolopyridium function in the oxazole dyes 3a and 3e. 1H and 1H DOSY solution NMR spectroscopy prove that slight structural changes result in significant differences in the process of self-association. The association constants for dimerization have been determined by curve fitting the concentration dependent 1H NMR spectra based on the isodesmic model. Van't Hoff analysis has been used to determine the thermodynamic parameters of the self-association process. The aggregation in water decreases with decreasing electronegativity and increasing the charge delocalization in the row (E)-2-(4-(dimethylamino)styryl)-3-methylbenzo[d]oxazol-3-ium iodide (3a), (E)-2-(4-(dimethylamino)styryl)-3-methylbenzo[d]thiazol-3-ium iodide (3b), (E)-2-(4-(dimethylamino)styryl)-3-methylbenzo[1,3-d]selenazol-3-ium iodide (3d) in the oxazole/thiazole/selenazole analogues. Introducing methyl groups in the benzothiazole ring enhances stacking effects in water due to stronger hydrophobic character. This derivative is characterized by the highest self-association constant (ka = 299 L mol?1) and the lowest Gibbs energy (ΔG = -14 kJ mol?1). Substituting the phenyl with pyridyl ring in the oxazole analogue enhances significantly the solubility in water and thus decreases the self-association constant. Concentration dependent 1H ROESY spectra provide information about the orientation of the molecules in the stack.
- Boecker, Marcel,Haese, Constantin,Mondeshki, Mihail,Vasilev, Aleksey
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- Benzothiazolium Derivative-Capped Silica Nanocomposites for β-Amyloid ImagingIn Vivo
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Alzheimer’s disease (AD) is a neurodegenerative disease, and β-amyloid (Aβ) is believed to be a causative factor in AD pathology. The abnormal deposition of Aβ is believed to be responsible for progression of AD. In order to facilitate the imaging of Aβin vivo, suitable probe molecules with a near-infrared emission wavelength that can penetrate the blood-brain barrier (BBB) were utilized. The commercial fluorescent probe thioflavin-T (ThT) is used to image Aβ; however, because of its short emission wavelength and poor BBB penetration, ThT can only be usedin vitro. With this research, based on ThT, we design three fluorescent probes (SZIs) having a longer emission wavelength in order to image Aβ aggregates. SZIs with different numbers of double bonds respond to Aβ aggregates. The SZIs have a structure similar to ThT, and as such, the SZIs are also unable to penetrate the BBB. To deal with the problem, we develop nanocomposites (MSN-Lf@SZIs) to deliver SZIs into the brain of AD mouse and image Aβ successfully. These new nanocomposites are able to deliver the dyes into the brain and facilitate Aβ imagingin vivo.
- Ma, Lijun,Yang, Shu,Ma, Yufan,Chen, Yuzhi,Wang, Zhenguo,James, Tony D.,Wang, Xuefei,Wang, Zhuo
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p. 12617 - 12627
(2021/09/30)
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- Design and Synthesis of Novel c-di-GMP G-Quadruplex Inducers as Bacterial Biofilm Inhibitors
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The formation of biofilms by clinical pathogens typically leads to chronic and recurring antibiotic-resistant infections. High cellular levels of cyclic diguanylate (c-di-GMP), a ubiquitous secondary messenger of bacteria, have been proven to be associate
- Chen, Wei-Min,Lin, Jing,Lin, Qian-Wen,Liu, Jun,Wang, Zi-Qiang,Xuan, Teng-Fei,Yu, Hai-Tao
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p. 11074 - 11089
(2021/08/20)
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- Engineering of Nucleic Acids and Synthetic Cofactors as Holo Sensors for Probing Signaling Molecules in the Cellular Membrane Microenvironment
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The comprehensive understanding of the mechanisms underlying the interaction of cells with their membrane microenvironment is of great value for fundamental biological research; however, tracking biomolecules on cell surfaces with high temporal and spatial resolution remains a challenge. Herein, a modular strategy is presented for the construction of cell surface DNA-based sensors by engineering DNA motifs and synthetic cofactors. In this strategy, a stimuli-reactive organic molecule is employed as the cofactor for the DNA motif, and the self-assembly of them forms a FRET-based holo DNA-based sensor. With the use of the DNA-based sensors, the versatility of this modular strategy has been demonstrated in the ratiometric imaging of the cellular extrusion process of endogenous signaling molecules, including sulfur dioxide derivatives and nitric oxide.
- Feng, Guangfu,Luo, Xingyu,Lu, Xu,Xie, Shiyi,Deng, Lu,Kang, Wenyuan,He, Fang,Zhang, Jiaheng,Lei, Chunyang,Lin, Bin,Huang, Yan,Nie, Zhou,Yao, Shouzhuo
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p. 6590 - 6594
(2019/05/14)
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- Fast (hetero)aryl-benzothiazolium ethenes photoswitches activated by visible-light at room temperature
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A series of novel photochromic cationic stilbenes dyes bearing different aromatic systems were easily synthesized from (hetero)aromatic aldehydes. The photoisomerization of the double bond can be achieved through irradiation with ultraviolet or visible light, for few seconds, leading to the Z isomers that return much faster to the initial state than common stilbenes. Benzothiazolium dyes with electron donating substituents exhibited very fast thermal back reactions (1 s). Pyrrole-benzothiazolium dye showed a higher lifetime of the Z isomer, in different solvents, including water (0.45-7.1 min). This cationic diarylethene can be switched between the E-Z states using visible light, in few minutes at room temperature, with a noticeable change in the visible spectrum.
- Coelho, Paulo J.,Castro, M. Cidália R.,Raposo, M. Manuela M.
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p. 163 - 169
(2015/03/30)
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- Photostability of D-π-A nonlinear optical chromophores containing a benzothiazolium acceptor
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For the practical application of second-order NLO materials, not only a high molecular quadratic hyperpolarizability β but also good thermal, chemical, and photochemical stabilities are required. Most of the state-of-the-art chromophores with high NLO res
- Cigan, Marek,Gaplovsky, Anton,Sigmundova, Ivica,Zahradnik, Pavol,Dedic, Roman,Hromadova, Magdalena
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supporting information; experimental part
p. 450 - 459
(2012/01/03)
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- Synthesis and study of novel benzothiazole derivatives with potential nonlinear optical properties
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The synthesis of new benzothiazole push-pull systems as candidates for NLO-phores is described. Spectral (UV/VIS and solvatochromic) and theoretical studies (electronic properties based on semiempirical AM1 and PM3 methods) of the prepared compounds were carried out. The structure and physico-chemical parameters affecting the push-pull character and intramolecular charge transfer (ICT) of the studied compounds have been investigated and compounds with enhanced hyperpolarizability β have been predicted. The benzothiazolium salts were found to be much more effective NLO-phores in comparison with the corresponding neutral benzothiazoles. The 4-NPh2 group is the most effective donor. The extension of conjugated bridge improves the studied NLO characteristics. An additional acceptor group bonded to the heterocycle causes a red shift of λmax but does not increase hyperpolarizability.
- Sigmundova, Ivica,Zahradnik, Pavol,Loos, Dusan
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p. 1069 - 1093
(2008/12/22)
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