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91.
Phenotypic and Target-Directed Screening Yields New Acaricidal Alternatives for the Control of Ticks
Tatiana Saporiti Mauricio Cabrera Josefina Bentancur María Elisa Ferrari Nallely Cabrera Ruy Prez-Montfort Francisco J. Aguirre-Crespo Jorge Gil Ulises Cuore Dimitris Matiadis Marina Sagnou Guzmn Alvarez 《Molecules (Basel, Switzerland)》2022,27(24)
Rhipicephalus microplus, the “common cattle tick”, is the most important ectoparasite in livestock worldwide due to the economic and health losses it produces. This tick is a vector for pathogens of several tick-borne diseases. In Latin American countries, damages reach approximately USD 500 million annually due to tick infections, as well as tick-borne diseases. Currently, resistant populations for every chemical group of acaricides have been reported, posing a serious problem for tick control. This study aims to find new alternatives for controlling resistant ticks with compounds derived from small synthetic organic molecules and natural origins. Using BME26 embryonic cells, we performed phenotypic screening of 44 natural extracts from 10 Mexican plants used in traditional medicine, and 33 compounds selected from our chemical collection. We found 10 extracts and 13 compounds that inhibited cell growth by 50% at 50 µg/mL and 100 µM, respectively; the dose-response profile of two of them was characterized, and these compounds were assayed in vitro against different life stages of Rhipicephalus microplus. We also performed a target-directed screening of the activity of triosephosphate isomerase, using 86 compounds selected from our chemical collection. In this collection, we found the most potent and selective inhibitor of tick triosephosphate isomerase reported until now. Two other compounds had a potent acaricidal effect in vitro using adults and larvae when compared with other acaricides such as ivermectin and Amitraz. Those compounds were also selective to the ticks compared with the cytotoxicity in mammalian cells like macrophages or bovine spermatozoids. They also had a good toxicological profile, resulting in promising acaricidal compounds for tick control in cattle raising. 相似文献
92.
Inma P. Cabrera Pablo Cordero Emilio Muñoz-Velasco Manuel Ojeda-Aciego Bernard De Baets 《Mathematical Methods in the Applied Sciences》2020,43(9):5673-5680
Fuzzy-directed graphs are often chosen as the data structure to model and implement solutions to several problems in the applied sciences. Galois connections have also shown to be useful both in theoretical and in practical problems. In this paper, the notion of relational Galois connection is extended to be applied between transitive fuzzy directed graphs. In this framework, the components of the connection are crisp relations satisfying certain reasonable properties given in terms of the so-called full powering. 相似文献
93.
J. M. Navarrete G. Muller T. Martinez L. Cabrera I. Gracia L. Fabila V. M. Urbina 《Czechoslovak Journal of Physics》2006,56(1):D695-D696
The favorable effects of fulvic acids as fertilizers are very well known and they have been used long time ago in their natural
state in dead leaves. Their extraction from natural sources is rather expensive, but the production of very similar carbon
amino saccharides by sugar oxidation has been industrially applied in Mexico. Good properties of this commercial product as
fertilizer have been proved empirically in different crops as well as at laboratory level, by the efficient absorption of
radioactive labeled mineral ions in vegetables when they are carried by this synthetic organic matter in aqueous solution.
Now, its effect has been tested by filtration of radioactively labeled 45Ca2+ and 32PO
4
3−
ions from drinking water to blood serum through mice liver and kidneys. The results indicate that the filtration and diffusion
of these mineral ions also improved, the same that in vegetables, in the presence of the synthetic carbon amino saccharides
highly soluble in water. These results suggest the appropriateness of further research to evaluate their possible use either
as a dietary complement or as auxiliaries in the treatment of liver and kidney diseases. 相似文献
94.
95.
De Abreu-García J. A. Niu X. Cabrera L. A. 《Journal of Optimization Theory and Applications》1998,99(2):331-358
In this paper, robustness bounds for the perturbations of continuous-time systems to ensure the stability of their discretized counterparts are developed. Both zero-order hold and P-step matrix integrators are considered. The effect of the sampling time on the robustness bounds is studied via examples. To determine how well a simulated system will retain the robustness properties of the continuous-time system being simulated, a new criterion for the selection of the simulation method and time step is introduced. Both implicit and explicit robustness measures for sampled-data systems are obtained. 相似文献
96.
T. Martinez J. Lartigue M. Navarrete P. Avila C. Lopez L. Cabrera V. Vilchis 《Journal of Radioanalytical and Nuclear Chemistry》1997,216(1):37-39
Metallic pollutants were measured in dwellings in Mexico City by instrumental neutron activation analysis (INAA) and X-ray fluorescence techniques. Monitoring was performed in the west side of the city and in the winter season. In general the average concentration of contaminants collected, when compared with the average concentrations reported in a previous paper, have increased with time and in the particular case of lead and mercury some samples are above the indicative WHO maximum levels. 相似文献
97.
If we change the sign of p ? m columns (or rows) of an m × m positive definite symmetric matrix A, the resultant matrix B has p negative eigenvalues. We give systems of inequalities for the eigenvalues of B and of the matrix obtained from B by deleting one row and column. To obtain these, we first develop characterizations of the eigenvalues of B which are analogous to the minimum-maximum properties of the eigenvalues of a symmetric A, i.e. the Courant-Fischer theorem. These results arose from studying probability distributions on the hyperboloid of revolution . By contrast, the familiar results are associated with the sphere x21 + ? + x2m = 1. 相似文献
98.
Manuel Salmón Armando Cabrera Nieves Zavala Georgina Espinosa-Pérez Jorge Cárdenas Rubén Gaviño Raymundo Cruz 《Journal of chemical crystallography》1995,25(11):759-762
3,4,5-Trimethoxybenzyl alcohol was cyclooligomerized with a bentonite clay used as a catalyst. Results of the crystal structure analysis of the racemic (±) nonamethoxy[1,1,1]orthocyclophane trimer, C30H36O9, are described. The structure was determined by X-ray diffraction at 293 K and shown to belong to the triclinic space group P
. The compound possesses a distorted crown conformation with unusual C–H...O intermolecular interactions, and with a crystal packing not observed before in other related derivatives. The racemic mixture was also discriminated in its two enantiomeric isomers, using proton NMR and Eu(III) as a chiral shift reagent. 相似文献
99.
100.
Perez A Vilkas MJ Cabrera CR Ishikawa Y 《The journal of physical chemistry. B》2005,109(49):23571-23578
A density functional theory study of the elementary steps that lead to the removal of CO(ads(Pt)) over alloyed and sequentially deposited Pt/Ru bimetallic nanoclusters is presented. The reaction energies and activation barriers for the H2O(ads(Ru)) dissociation and CO(ads(Pt)) + OH(ads(Ru)) reaction are estimated in solid-gas interface and in a microsolvated environment to determine which surface morphology is more tolerant to COads poisoning. On the basis of the energetics, the sequentially deposited Pt/Ru nanocluster is predicted to be a much more promising anode catalyst than the alloy cluster surface in fuel cell applications. 相似文献