nuclear magnetic resonance spectra
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Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7556
Author(s):  
Shengsheng Lu ◽  
Jianan Hu ◽  
Xi Xie ◽  
Runhong Zhou ◽  
Fangfang Li ◽  
...  

A new aliphatic acid, compound 1, together with six known metabolites, including nonactic acid (2), homononactic acid (3), ethyl homononactate (4), homononactylhomononactate (5), valinomycin (6), and cyclo-(Pro-Leu) (7), was isolated from the culture broth of Streptomyces sp. BM-8, an actinobacterial strain isolated from the feces of Equus quagga. The structures of these compounds were established by analyses of spectroscopic data, including 1D and 2D nuclear magnetic resonance spectra (NMR), as well as by HR-ESI-MS spectrometry and chemical derivative analyses. Additionally, a serial analogue of nonactic acid and homononacticacid (8–21) was synthesized. The cytotoxicity of 1–21 wastested against a panel of cancer cell lines, such as HT-29, MCF-7, A375 and K562, with MTT assay. In addition, the cytotoxicity tests revealed that 1 was less cytotoxic toward a panel of cancerous cells, as compared with valinomycin (6).


2021 ◽  
Author(s):  
Ivan Korendovych ◽  
Sagar Bhattacharya ◽  
Eleanora Margheritis ◽  
Katsuya Takahashi ◽  
Alona Kulesha ◽  
...  

Abstract Directed evolution can rapidly achieve dramatic improvements in the properties of a protein or bestow entirely new functions on it. We have discovered a strong correlation between the probability of finding a productive mutation at a particular position of a protein and a chemical shift perturbation in Nuclear Magnetic Resonance spectra upon addition of an inhibitor for the chemical reaction it promotes. In a proof-of-concept study we converted myoglobin, a non-enzymatic protein, into the most active Kemp eliminase reported to date using only three mutations. The observed levels of catalytic efficiency are on par with the levels shown by natural enzymes. This simple approach, that requires no a priori structural or bioinformatic knowledge, is widely applicable and will unleash the full potential of directed evolution.


2021 ◽  
Author(s):  
◽  
Anton Francis Erasmuson

<p>In a program aimed at developing a chemically derived vaccine against sporidesmin-A, the toxin which causes the pasture disease facial eczema, two haptens have been prepared, coupled to protein carriers, and tested for immunogenicity. The hapten, 2-amino-5-chloro-3,4-dimethoxybenzyl alcohol has been synthesised from vanillin and the general synthetic methods developed in the course of this work have been used to prepare a large number of related vanillin derivatives for use in cross-hapten studies. The carbon-13 nuclear magnetic resonance spectra of 16 vanillin derivatives have been obtained, and two independent methods of deducing vanillin substitution patterns have been developed. 5-chloro-6, 7-dimethoxy-N-methyl-lH-indole has been prepared by a new route and its 3-oxoacetic acid derivative has been synthesized for use as a hapten. The Vilsmeier-Haack intermediate, l-methyl-3-(N,N-dimethylimonio) methyl-lH-indole chloride was isolated and a number of possible synthetic routes from it to pyrroloindoles were explored. The vanillin and indole haptens have been coupled to protein carriers to form antigens which generated a low antibody response. However, the use of mycobacterium phlei as a carrier greatly increased the antibody response but the antibodies produced did not interact strongly with sporidesmin-A.</p>


2021 ◽  
Author(s):  
◽  
Anton Francis Erasmuson

<p>In a program aimed at developing a chemically derived vaccine against sporidesmin-A, the toxin which causes the pasture disease facial eczema, two haptens have been prepared, coupled to protein carriers, and tested for immunogenicity. The hapten, 2-amino-5-chloro-3,4-dimethoxybenzyl alcohol has been synthesised from vanillin and the general synthetic methods developed in the course of this work have been used to prepare a large number of related vanillin derivatives for use in cross-hapten studies. The carbon-13 nuclear magnetic resonance spectra of 16 vanillin derivatives have been obtained, and two independent methods of deducing vanillin substitution patterns have been developed. 5-chloro-6, 7-dimethoxy-N-methyl-lH-indole has been prepared by a new route and its 3-oxoacetic acid derivative has been synthesized for use as a hapten. The Vilsmeier-Haack intermediate, l-methyl-3-(N,N-dimethylimonio) methyl-lH-indole chloride was isolated and a number of possible synthetic routes from it to pyrroloindoles were explored. The vanillin and indole haptens have been coupled to protein carriers to form antigens which generated a low antibody response. However, the use of mycobacterium phlei as a carrier greatly increased the antibody response but the antibodies produced did not interact strongly with sporidesmin-A.</p>


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5272
Author(s):  
Rong Zhong ◽  
Hui Hu ◽  
Yanfang Zhou

A trifunctional photoinitiator based on commercial photoinitiators 2-hydroxy-2-methylpropiophenone (Irgacure1173) and 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (Irgacure2959) was synthesized by an esterization reaction. Its structure was characterized by UV-Vis spectrometry, Infrared Transformed Fourier, Proton Nuclear Magnetic Resonance Spectra, 13 Carbon Nuclear Magnetic Resonance Spectra, Mass Spectrometry, and Thermogravimetry. In addition, its photoinitiating activity was investigated. The results showed that the novel photoinitiator had good photoinitiating activity and thermal stability compared to commercial photoinitiators. The migration of the residual photoinitiator in the cured film was lower than that of 1173 and 2959.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jiayi Liu ◽  
Juan Hua ◽  
Bo Qu ◽  
Xuanyue Guo ◽  
Yangyang Wang ◽  
...  

Essential oils (EOs) are often the source of insecticidal substances of high efficiency and low toxicity. From gas chromatograph-mass spectrometer, column chromatography, and nuclear magnetic resonance spectra analyses, twenty terpenes were identified from the EOs of Artemisia nakaii. These comprised mostly monoterpenes (49.01%) and sesquiterpenes (50.76%). The terpenes at the highest concentrations in the EOs of A. nakaii were feropodin (200.46 ± 1.42 μg/ml), (+)-camphor (154.93 ± 9.72 μg/ml), β-selinene (57.73 ± 2.48 μg/ml), and 1,8-cineole (17.99 ± 1.06 μg/ml), calculated using area normalization and external standards. The EOs were tested for biological activity and showed strong fumigant toxicity and significant antifeedant activity against the larvae of Spodoptera litura. Furthermore, the monoterpenes 1,8-cineole and (+)-camphor displayed significant fumigant activity against S. litura, with LC50 values of 7.00 ± 0.85 and 18.16 ± 2.31 μl/L, respectively. Antifeedant activity of the sesquiterpenes feropodin and β-selinene was obvious, with EC50 values of 12.23 ± 2.60 and 10.46 ± 0.27 μg/cm2, respectively. The EOs and β-selinene were also found to inhibit acetylcholinesterase, with IC50 values of 37.75 ± 3.59 and 6.88 ± 0.48 μg/ml, respectively. These results suggest that monoterpenes and sesquiterpenes from the EOs of A. nakaii could potentially be applied as a botanical pesticides in the control of S. litura.


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