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排序方式: 共有168条查询结果,搜索用时 62 毫秒
91.
Dr. Moustafa Malki Dr. Santiago Casado Dr. María Francisca López Dr. Renaud Caillard Dr. F. Javier Palomares Dr. José A. Martín Gago Dr. Cristina Vaz‐Domínguez Dr. Angel Cuesta Prof. Ricardo Amils Prof. Víctor M. Fernández Dr. Marisela Velez Dr. Antonio L. De Lacey Dr. David Olea 《Chemphyschem》2013,14(6):1237-1244
The biofilm formation of a strain of the extremophile bacterium Acidiphilium sp., capable of donating electrons directly to electrodes, was studied by different surface characterization techniques. We develop a method that allows the simultaneous study of bacterial biofilms by means of fluorescence microscopy and atomic force microscopy (AFM), in which transparent graphitic flakes deposited on a glass substrate are used as a support for the biofilm. The majority of the cells present on the surface were viable, and the growth of the biofilms over time showed a critical increase of the extracellular polymeric substances (EPS) as well as the formation of nanosized particles inside the biofilm. Also, the presence of Fe in Acidiphilium biofilms was determined by X‐ray photoelectron spectroscopy (XPS), whereas surface‐enhanced infrared absorption spectroscopy indicated the presence of redox‐active proteins. 相似文献
92.
Hiranthi Jayasuriya KithsiriB. Herath Chaowei Zhang DeborahL. Zink Angela Basilio Olga Genilloud MariaTeresa Diez Francisca Vicente Ignacio Gonzalez Oscar Salazar Fernando Pelaez Richard Cummings Sookhee Ha Jun Wang SheoB. Singh 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2007,119(25):4768-4772
93.
Fernando J. S. Oliveira Leonardo Vazquez Norberto P. De Campos Francisca P. de Fran?a 《Applied biochemistry and biotechnology》1996,131(1-3):727-737
Biosurfactants production by a strain of Pseudomonas aeruginosa using palm oil as a sole carbon source was investigated. The experiments were carried out in 500-mL conical flasks containing
100 mL of mineral media supplemented with palm oil as the sole carbon source. The P. aeruginosa FR strain was able to reduce surface tension of three tested inorganic media. Rotation velocities from 100 to 150 rpm provided
free-cell fermented media with the lowest surface tension of approx 33 mN/m. Emulsification index results of even 100% were
achieved when diesel was used as oil phase. Eight surface-active compounds produced by the bacterium were identified by mass
spectrometry. 相似文献
94.
The synthesis and characterization of three heteronuclear Pt(2)Pd(2) (4, 5) and PtPd(2) (6) complexes of the model nucleobase 9-methyladenine (9-MeA) is reported. The compounds were prepared by reacting [Pt(NH(3))(3)(9-MeA-N7)](ClO(4))(2) (1) with [Pd(en)(H(2)O)(2)](ClO(4))(2) at different ratios r between Pt and Pd, with the goal to probe Pd(II) binding to any of the three available nitrogen atoms, N1, N3, N6 or combinations thereof. Pd(II) coordination occurs at N1 and at the deprotonated N6 positions, yet not at N3. 4 and 5 are isomers of [{(en)Pd}(2){N1,N6-9-MeA(-)-N7)Pt(NH(3))(3)}(2)](ClO(4))(6)·nH(2)O, with a head-head orientation of the two bridging 9-MeA(-) ligands in 4 and a head-tail orientation in 5. 6 is [{(en)Pd}(2)(OH)(N1,N6-9MeA(-)-N7)Pt(NH(3))(3)](ClO(4))(4)·4H(2)O, hence a condensation product between [Pt(NH(3))(3)(9-MeA-N7)](2+) and a μ-OH bridged dinuclear (en)Pd-OH-Pd(en) unit, which connects the N1 and N6 positions of 9-MeA(-) in an intramolecular fashion. 4 and 5, which slowly interconvert in aqueous solution, display distinct structural differences such as significantly different intramolecular Pd···Pd contacts (3.124 0(16) ? in 4; 2.986 6(14) ? in 5), among others. Binding of (en)Pd(II) to the exocyclic N6 atom in 4 and 5 is accompanied by a large movement of Pd(II) out of the 9-MeA(-) plane and a trend to a further shortening of the C6-N6 bond as compared to free 9-MeA. The packing patterns of 4 and 5 reveal substantial anion-π interactions. 相似文献
95.
Enzymatic catalysis has become a common tool in both academia and industrial chemistry. The efforts of chemists over recent decades have led to the rationalization of the mechanism of action of biocatalysts, which have been routinely incorporated into many synthetic sequences. Nowadays, a further step consists in expanding the application of enzymes to the modification of complex molecular scaffolds common to many pharmaceutical leads isolated from nature. Regioselective enzymatic acylation is a process which has been profitably applied for this purpose in recent times, leading to new drugs with improved activity, stability and pharmacokinetic properties. This tutorial review provides an overview of this subject employing two classes of enzymes, hydrolases and acyltransferases, in the recently concluded decade although some representative older studies are commented upon, if required. We shall place special emphasis on those examples in which the novel acylated derivatives have improved the activity or properties of the parental molecules. 相似文献
96.
Painted in 1925 or 1926, over an older composition, La salle d'armes, is among the first Magritte's surrealist paintings. It is also one of the only four Magritte's using enamels reported in the René Magritte Catalog Raisonné. This paper presents the material and technical study conducted on this double painting. The complementary imaging and analytical methods applied for this purpose provided substantial information on both, the visible image and the hidden one. Concerning the latter, for instance, the obtained results permitted to identify a cubo-futurist oil painting from the very early 1920s. 相似文献
97.
98.
Aike C. da Silva Fernando J. S. de Oliveira Diogo S. Bernardes Francisca P. de França 《Applied biochemistry and biotechnology》2009,153(1-3):58-66
The aim of this work was to optimize the bioremediation of crude oil-contaminated sand sediment through the biostimulation technique. The soil was obtained in the mid-tide zone of Guanabara Bay, Rio de Janeiro, Brazil and was artificially contaminated with crude oil at 14 g kg?1. Bioremediation optimization was performed using an experimental design and statistical analysis of the following factors: supplementation with commercial biosurfactant Jeneil® IBR 425 and commercial mineral NPK fertilizer. The response variable used was the biodegradation of the heavy oil fraction, HOF. The analysis of the studied factors and their interactions was executed using contour plots, Pareto diagram and ANOVA table. Experimental design results indicated that the supplementation with fertilizer at 100:25:25 C/N/P ratio and biosurfactant at 2 g kg?1 yielded biodegradation of HOF at about 30% during 30 days of process. Some experiments were carried out using the experimental design results, yielding 65% of biodegradation of HOF and 100% of n- alkanes between C15 and C30 during 60 process days. Intrinsic biodegradation test was carried out, yielding 85% of biodegradation of n-alkanes between C15 and C30 during 30 days of process. 相似文献
99.
Rodney Lacret Daniel Oves-Costales Ignacio Pérez-Victoria Mercedes de la Cruz Caridad Díaz Francisca Vicente 《Natural product research》2019,33(1):66-73
A new medermycin derivative, MDN-0171 (1), and two known structurally related compounds, medermycin (2) and antibiotic G15-F (3) were isolated from the acetone extract of culture broths of the marine-derived Streptomyces albolongus strain CA-186053. Their structures were determined using a combination of spectroscopic techniques, including 1D and 2D NMR and electrospray-time of flight mass spectrometry (ESI-TOF MS). Compounds 2 and 3 accounted for the antimicrobial activity (against methicillin-resistant Staphylococcus aureus and Escherichia coli) previously detected in the crude extract of this actinomycete. 相似文献
100.
María Gonzlez-Rodríguez Clara Ruiz-Fernndez Vera Francisco Djedjiga Ait Eldjoudi Yousof Ramadan Farrag AbdElHafez Alfonso Cordero-Barreal Jesus Pino Francisca Lago Manuel Campos-Toimil Glaucimeire Rocha Carvalho Thiago Melo Costa Pereira Oreste Gualillo 《Molecules (Basel, Switzerland)》2021,26(4)
Virola is the largest genus of Myristicaceae in America, comprising about 60 species of medium-sized trees geographically spread from Mexico to southern Brazil. The plant species of this genus have been widely used in folk medicine for the treatment of several ailments, such as rheumatic pain, bronchial asthma, tumors in the joints, intestinal worms, halitosis, ulcers, and multiple infections, due to their pharmacological activity. This review presents an updated and comprehensive summary of Virola species, particularly their ethnomedicinal uses, phytochemistry, and biological activity, to support the safe medicinal use of plant extracts and provide guidance for future research. The Virola spp.’s ethnopharmacology, including in the treatment of stomach pain and gastric ulcers, as well as antimicrobial and tryponosomicidal activities, is attributable to the presence of a myriad of phytoconstituents, such as flavonoids, tannins, phenolic acids, lignans, arylalkanones, and sitosterol. Hence, such species yield potential leads or molecular scaffolds for the development of new pharmaceutical formulations, encouraging the elucidation of not-yet-understood action mechanisms and ascertaining their safety for humans. 相似文献