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排序方式: 共有253条查询结果,搜索用时 31 毫秒
141.
Urquiola C Vieites M Aguirre G Marín A Solano B Arrambide G Noblía P Lavaggi ML Torre MH González M Monge A Gambino D Cerecetto H 《Bioorganic & medicinal chemistry》2006,14(16):5503-5509
New vanadium complexes of the type [V(IV)O(L)(2)], where L are 3-aminoquinoxaline-2-carbonitrile N(1),N(4)-dioxide derivatives, were prepared as an effort to obtain new anti-trypanosomal agents improving the bioactivity of the free ligands. Complexation to vanadium of the quinoxaline ligands leads to excellent antiprotozoal activity, similar to that of the reference drugs nifurtimox and benznidazole and in all cases higher than that of the corresponding free ligands. In addition, it is for the first time that the V((IV))O-quinoxaline complexes are reported as a family of anti-Trypanosoma cruzi agents. Finally, the anti-trypanosomal activity of these vanadium complexes could be explained on the basis of their lipophilicity and the electronic characteristics of the quinoxaline substituents. 相似文献
142.
143.
Karl Rumbold Hugo JJ van Buijsen Karin M Overkamp Johan W van Groenestijn Peter J Punt J van der Mari?t Werf 《Microbial cell factories》2009,8(1):64
Background
Increasingly lignocellulosic biomass hydrolysates are used as the feedstock for industrial fermentations. These biomass hydrolysates are complex mixtures of different fermentable sugars, but also inhibitors and salts that affect the performance of the microbial production host. The performance of six industrially relevant microorganisms, i.e. two bacteria (Escherichia coli and Corynebacterium glutamicum), two yeasts (Saccharomyces cerevisiae and Pichia stipitis) and two fungi (Aspergillus niger and Trichoderma reesei) were compared for their (i) ability to utilize monosaccharides present in lignocellulosic hydrolysates, (ii) resistance against inhibitors present in lignocellulosic hydrolysates, (iii) their ability to utilize and grow on different feedstock hydrolysates (corn stover, wheat straw, sugar cane bagasse and willow wood). The feedstock hydrolysates were generated in two manners: (i) thermal pretreatment under mild acid conditions followed by enzymatic hydrolysis and (ii) a non-enzymatic method in which the lignocellulosic biomass is pretreated and hydrolyzed by concentrated sulfuric acid. Moreover, the ability of the selected hosts to utilize waste glycerol from the biodiesel industry was evaluated. 相似文献144.
Jacques M Mathieu John Schloendorn Bruce E Rittmann Pedro JJ Alvarez 《Microbial cell factories》2009,8(1):21-18
Catabolic insufficiency in humans leads to the gradual accumulation of a number of pathogenic compounds associated with age-related
diseases, including atherosclerosis, Alzheimer's disease, and macular degeneration. Removal of these compounds is a widely
researched therapeutic option, but the use of antibodies and endogenous human enzymes has failed to produce effective treatments,
and may pose risks to cellular homeostasis. Another alternative is "medical bioremediation," the use of microbial enzymes
to augment missing catabolic functions. The microbial genetic diversity in most natural environments provides a resource that
can be mined for enzymes capable of degrading just about any energy-rich organic compound. This review discusses targets for
biodegradation, the identification of candidate microbial enzymes, and enzyme-delivery methods. 相似文献
145.
146.
M. Belén Tarallo Antonio Monge Ronny R. Ribeiro Roberto C. Mercader Clarice Q.F. Leite Dinorah Gambino 《Journal of inorganic biochemistry》2010,104(11):1164-1170
In the search for new therapeutic tools against tuberculosis two novel iron complexes, [Fe(L-H)3], with 3-aminoquinoxaline-2-carbonitrile N1,N4-dioxide derivatives (L) as ligands, were synthesized, characterized by a combination of techniques, and in vitro evaluated. Results were compared with those previously reported for two analogous iron complexes of other ligands of the same family of quinoxaline derivatives. In addition, the complexes were studied by cyclic voltammetry and EPR spectroscopy. Cyclic voltammograms of the iron compounds showed several cathodic processes which were attributed to the reduction of the metal center (Fe(III)/Fe(II)) and the coordinated ligand. EPR signals were characteristic of magnetically isolated high-spin Fe(III) in a rhombic environment and arise from transitions between mS = ± 1/2 (geff ~ 9) or mS = ± 3/2 (geff ~ 4.3) states. Mössbauer experiments showed hyperfine parameters that are typical of high-spin Fe(III) ions in a not too distorted environment. The novel complexes showed in vitro growth inhibitory activity on Mycobacterium tuberculosis H37Rv (ATCC 27294), together with very low unspecific cytotoxicity on eukaryotic cells (cultured murine cell line J774). Both complexes showed higher inhibitory effects on M. tuberculosis than the “second-line” therapeutic drugs. 相似文献
147.
A Rapid and effective method for RNA extraction from different tissues of grapevine and other woody plants 总被引:1,自引:0,他引:1
Introduction – RNA quality and integrity are critical for many studies in plant molecular biology. High‐quality RNA extraction from grapevine and other woody plants is problematic due to the presence of polysaccharides, polyphenolics and other compounds that bind or co‐precipitate with the RNA. Objective – To develop an optimised cetyltrimethylammonium bromide (CTAB)‐based protocol, to reduce the time and cost of extraction without reducing quality and yield of RNA extracted from polysaccharide‐rich tissues of several plants. Methodology – Several changes were introduced to the original CTAB protocol. All centrifugation steps were carried out at 4°C, the sample weight was decreased and the concentrations of PVP‐40 and LiCl were increased reducing incubation time prior to RNA precipitation. This rapid CTAB protocol was compared with six different RNA extraction methods from three grapevine tissues, namely, in vitro plantlets, and leaves and mature canes from actively growing field vines. Results – The rapid CTAB method gave high‐quality RNA in only 3 h at low cost with efficiency equal to or higher than that obtained with other time‐consuming and expensive protocols. The procedure was applied to RNA extraction from other grapevine tissues and other woody species including olive, lemon, poplar, chestnut, apple, pear, peach, cherry, apricot, plum and kiwi fruit. RNA of high quality could be isolated from all tissues and from all species. Conclusion – The study has shown that the improvement of a CTAB‐based protocol allows the rapid isolation of high‐quality RNA from grapevine and many woody species. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
148.
149.
Romancino DP Dalmazio S Cervello M Montana G Virruso L Bonura A Gambino R Di Carlo M 《Mechanisms of development》2000,99(1-2):113-121
COLL1alpha mRNA is asymmetrically distributed in the Paracentrotus lividus egg. Here we examine the involvement of the cytoskeleton in the localization process of collagen mRNA. The use of drugs such as colchicine and cytochalasin B reveals a perturbation of localization collagen mRNA. Moreover, the presence of specific cis-and trans-acting factors involved in cytoskeleton binding and the localization process was investigated. By Northwestern experiment we found that the 3'UTR of COLL1alpha mRNA is also able to bind two proteins of 54 and 40 kDa in a cellular fraction containing the cytoskeleton. Finally, we found that the protein of 54 kDa is LP54, a protein that binds the 3'UTRs of P. lividus maternal bep messengers and is necessary for their localization. 相似文献
150.
Comparison of the evolutionary dynamics of symbiotic and housekeeping loci: a case for the genetic coherence of rhizobial lineages 总被引:6,自引:1,他引:5
In prokaryotes, lateral gene transfer across chromosomal lineages may be
mediated by plasmids, phages, transposable elements, and other accessory
DNA elements. However, the importance of such transfer and the evolutionary
forces that may restrict gene exchange remain largely unexplored in native
settings. In this study, tests of phylogenetic congruence are employed to
explore the range of horizontal transfer of symbiotic (sym) loci among
distinct chromosomal lineages of native rhizobia, the nitrogen-fixing
symbiont of legumes. Rhizobial strains isolated from nodules of several
host plant genera were sequenced at three loci: symbiotic nodulation genes
(nodB and nodC), the chromosomal housekeeping locus glutamine synthetase II
(GSII), and a portion of the 16S rRNA gene. Molecular phylogenetic analysis
shows that each locus generally subdivides strains into the same major
groups, which correspond to the genera Rhizobium, Sinorhizobium, and
Mesorhizobium. This broad phylogenetic congruence indicates a lack of
lateral transfer across major chromosomal subdivisions, and it contrasts
with previous studies of agricultural populations showing broad transfer of
sym loci across divergent chromosomal lineages. A general correspondence of
the three rhizobial genera with major legume groups suggests that host
plant associations may be important in the differentiation of rhizobial nod
and chromosomal loci and may restrict lateral transfer among strains. The
second major result is a significant incongruence of nod and GSII
phylogenies within rhizobial subdivisions, which strongly suggests
horizontal transfer of nod genes among congenerics. This combined evidence
for lateral gene transfer within, but not between, genetic subdivisions
supports the view that rhizobial genera are "reproductively isolated" and
diverge independently. Differences across rhizobial genera in the
specificity of host associations imply that the evolutionary dynamics of
the symbiosis vary considerably across lineages in native settings.
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