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81.
Allison Leyton Michael Araya Fadia Tala Liset Flores María Elena Lienqueo Carolina Shene 《Molecules (Basel, Switzerland)》2021,26(8)
Seaweed processing generates liquid fraction residual that could be used as a low-cost nutrient source for microbial production of metabolites. The Rhodotorula strain is able to produce antimicrobial compounds known as sophorolipids. Our aim was to evaluate sophorolipid production, with antibacterial activity, by marine Rhodotorula rubra using liquid fraction residual (LFR) from the brown seaweed Macrocystis pyrifera as the nutrient source. LFR having a composition of 32% w/w carbohydrate, 1% w/w lipids, 15% w/w protein and 52% w/w ash. The best culture condition for sophorolipid production was LFR 40% v/v, without yeast extract, artificial seawater 80% v/v at 15 °C by 3 growth days, with the antibacterial activity of 24.4 ± 3.1 % on Escherichia coli and 21.1 ± 3.8 % on Staphylococcus aureus. It was possible to identify mono-acetylated acidic and methyl ester acidic sophorolipid. These compounds possess potential as pathogen controllers for application in the food industry. 相似文献
82.
A self-propelled object coupled with an enzyme reaction between urease and urea was investigated at the air/aqueous interface. A plastic object that was fixed to a urease-immobilized filter paper was used as a self-propelled object, termed a urease motor, placed on an aqueous urea solution. The driving force of the urease motor is the difference in the surface tension around the object. Oscillatory motion or no motion was triggered depending on the initial pH of the urea solution. Both the frequency and maximum speed of the oscillatory motion varied depending on the initial pH of the water phase. The mechanisms underlying the oscillatory motion and no motion were discussed in relation to the bell-shaped enzyme activity of urease in the enzyme reaction and the surface tension around the urease motor. 相似文献
83.
本文合成了配合物[Cu(pcba)2·(phen)(H2O)] (pcba =对氯苯甲酸,phen = 1,10-邻菲罗啉),该配合物属于三斜晶系,P1空间群,晶胞参数为a=0.790 98(2) nm,b=1.072 40(4) nm,c=1.487 19(6) nm,α=100.613(3)°,β=95.239(3)°,γ=108.334(3)°,Z=2,Dc=1.638 g·cm-3,F(000)=582,最终结构残差因子R1=0.035 9,wR2=0.089 1。采用紫外及荧光研究了配合物和人血清蛋白(HSA)的相互作用方式。结果表明,配合物静态猝灭HSA荧光,可求得配合物与HSA的猝灭常数Ksv=2.35×105 L·mol-1,猝灭速率常数Kq=2.35×1013 L·mol-1·s-1,结合常数为Ka=2.14×1013 L·mol-1,结合位点n=2.37。同时,研究了配合物对胃癌细胞A549、宫颈癌细胞Hela和肝癌细胞HepG2的抗增殖能力。 相似文献
84.
Li-Hua Su Tian-Ze Li Yun-Bao Ma Chang-An Geng Xiao-Yan Huang Xin Zhang Zhen Gao Ji-Jun Chen 《中国化学》2022,40(1):104-114
Inspired by the intriguing structures and remarkable activities of sesquiterpenoid dimers,12 new sesquiterpenoid dimers,artematrovirenolides A—D(1—4)and artematrolides S—Z(8—12),were isolated from the EtOAc fraction of Artemisia atrovirens through a bioactivity-guided approach.Their structures were elucidated by comprehensive spectroscopic data and absolute configuration was assigned based on single crystal X-ray diffraction data and ECD calculations.Structurally,all compounds are presumably formed via[4+2]cycloaddition involving three connecting model.Compounds 1—4 are four novel hetero-dimeric[4+2]Diels-Alder adducts dimerized from a rotundane-type unit and a guaiane-type monomer,and compounds 5—12 are eight new homo-dimeric[4+2]adducts derived from two guaianolide moieties.A putative biosynthetic pathway for compounds 1—4 was also proposed.Compounds 4,6,7,and 10 demonstrated moderate cytotoxicity against HepG2,SMMC-7721,and Huh7 cell lines with IC50 values ranging from 9.3 to 62.3μmol/L.Interestingly,compounds 5 and 11 manifested cytotoxicity with IC50 values of 13.6 and 12.8(HepG2),18.5 and 13.1(SMMC-7721),and 16.5 and 19.4μmol/L(Huh7),respectively,which were equivalent to the positive control,sorafenib.This investigation suggests that compounds 5 and 11 might be considered as potent antihepatoma candidates and deserve further structural modification and mechanism study. 相似文献
85.
Dr. Jana Hudecová Dr. Josef Kapitán Prof. Martin Dračínský Pavel Michal Dr. Václav Profant Prof. Petr Bouř 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(59):e202202045
The histidine residue has an exceptional affinity for metals, but solution structure of its complexes are difficult to study. For zinc and nickel complexes, Raman and Raman optical activity (ROA) spectroscopy methods to investigate the link between spectral shapes and the geometry were used. The spectra were recorded and interpreted on the basis of ionic equilibria, molecular dynamics, ab initio molecular dynamics, and density functional theory. For zwitterionic histidine the dominant tautomer was determined by the decomposition of experimental spectra into calculated subspectra. An octahedral structure was found to prevail for the ZnHis2 complex in solution, in contrast to a tetrahedral arrangement in the crystal phase. The solution geometry of NiHis2 is more similar to the octahedral structure found by X-ray. The Raman and ROA structural determinations of metal complexes are dependent on extensive computations, but reveal unique information about the studied systems. 相似文献
86.
《Mendeleev Communications》2022,32(3):357-359
Mild and ‘green’ ultrasound-assisted reaction of chitin with 3-(chloromethyl)[1,2,4]selenadiazolo[4,5-a]pyridin-4-ium bromide in water affords novel selenium-containing cationic chitin derivatives. The thus obtained chitin derivatives are water soluble and are characterized by high in vitro antifungal activity comparable with conventional antifungal drug Amphotericin B. 相似文献
87.
《印度化学会志》2023,100(6):101010
A new azo derivative 3-((4-H1benzo[d]imidazole-2-yl)-4-hydroxy benzaldehyde was prepared by reaction of benzimidazole derivative with 4-hydroxy benzaldehyde. The all-final compounds were diagnosis and determined the structure of these compounds using a variety of spectroscopic methods, including 1H-NMR, FT-IR, UV-Vis, mass spectrometry magnetic susceptibility and atomic absorption spectroscopy. The results showed that all metal ion complexes have an octahedral shape. Antimicrobial activity of the ligand and its metal ion complex had been tested against some selected microorganism such Streptococcus pyogenes a species of Gram-positive and Pseudomonas aeruginosa is a common bacterium gram-negative, all prepared compounds displayed a strong antibacterial activity. Taken together, the results of the current study indicated that the new Azo derivative and their divalent metal ion complexes could be used as a future strategy for other biomedical applications. 相似文献
88.
Dielectrophoresis (DEP) is an AC electrokinetic effect that is proven to be effective for the immobilization of not only cells, but also of macromolecules, for example, antibodies and enzyme molecules. In our previous work, we have already demonstrated the high catalytic activity of immobilized horseradish peroxidase after DEP. To evaluate the suitability of the immobilization method for sensing or research in general, we want to test it for other enzymes, too. In this study, glucose oxidase (GOX) from Aspergillus niger was immobilized on TiN nanoelectrode arrays by DEP. Fluorescence microscopy showed the intrinsic fluorescence of the immobilized enzymes flavin cofactor on the electrodes. The catalytic activity of immobilized GOX was detectable, but a fraction of less than 1.3% of the maximum activity that was expected for a full monolayer of immobilized enzymes on all electrodes was stable for multiple measurement cycles. Therefore, the effect of DEP immobilization on the catalytic activity strongly depends on the used enzyme. 相似文献
89.
《Mendeleev Communications》2023,33(2):240-242
A series of new cationic amphiphiles based on diethanolamine esters with Gly, βAla, GABA, Lys, Orn amino acid residues in the hydrophilic block were prepared. The sample containing the Lys residue showed the best activity against gram-positive and gram-negative bacteria. For model membranes comprising combinations of DOPC, DOPG and DOPE phospholipids, the sample can electrostatically bind to the surface of a bacterial cell and destroy it by formation of through defects. 相似文献
90.
《Mendeleev Communications》2023,33(2):249-251
The reactions between Ph3As and ω-bromoalkanoic acids with the length of polymethylene fragment n = 5, 7, 9 afford quaternary arsonium salts. Their treatment with alkali gives biologically active arsenobetaines. Solvent-free reactions of Ph3P or Ph3As with 2,3-dibromopropionic acid lead to the corresponding arsonium and phosphonium salts bearing (CH2)2COOH substituent. 相似文献