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51.
Núbia Boechat Alcione S Carvalho Kelly Salom?o Solange L de Castro Carlos F Araujo-Lima Francisco VC Mello Israel Felzenszwalb Claudia AF Aiub Taline Ramos Conde Helena PS Zamith Rolf Skupin Günter Haufe 《Memórias do Instituto Oswaldo Cruz》2015,110(4):492-499
Nitroimidazoles exhibit high microbicidal activity, but mutagenic, genotoxic and
cytotoxic properties have been attributed to the presence of the nitro group.
However, we synthesised nitroimidazoles with activity against the trypomastigotes of
Trypanosoma cruzi, but that were not genotoxic. Herein,
nitroimidazoles (11-19) bearing different substituent groups were investigated for
their potential induction of genotoxicity (comet assay) and mutagenicity
(Salmonella/Microsome assay) and the correlations of these
effects with their trypanocidal effect and with megazol were investigated. The
compounds were designed to analyse the role played by the position of the nitro group
in the imidazole nucleus (C-4 or C-5) and the presence of oxidisable
groups at N-1 as an anion receptor group and the role of a methyl group at C-2.
Nitroimidazoles bearing NO2 at C-4 and CH3 at C-2 were not genotoxic compared to
those bearing NO2 at C-5. However, when there was a CH3
at C-2, the position of the NO2 group had no influence on the genotoxic activity.
Fluorinated compounds exhibited higher genotoxicity regardless of the presence of CH3
at C-2 or NO2 at C-4 or C-5. However, in compounds 11 (2-CH3; 4-NO2; N-CH2OHCH2Cl)
and 12 (2-CH3; 4-NO2; N-CH2OHCH2F), the fluorine atom had no influence on
genotoxicity. This study contributes to the future search for new and safer
prototypes and provide. 相似文献
52.
53.
Background
Small molecular cofactors or ligands play a crucial role in the proper functioning of cells. Accurate annotation of their target proteins and binding sites is required for the complete understanding of reaction mechanisms. Nicotinamide adenine dinucleotide (NAD+ or NAD) is one of the most commonly used organic cofactors in living cells, which plays a critical role in cellular metabolism, storage and regulatory processes. In the past, several NAD binding proteins (NADBP) have been reported in the literature, which are responsible for a wide-range of activities in the cell. Attempts have been made to derive a rule for the binding of NAD+ to its target proteins. However, so far an efficient model could not be derived due to the time consuming process of structure determination, and limitations of similarity based approaches. Thus a sequence and non-similarity based method is needed to characterize the NAD binding sites to help in the annotation. In this study attempts have been made to predict NAD binding proteins and their interacting residues (NIRs) from amino acid sequence using bioinformatics tools. 相似文献54.
Background
The nucleus, a highly organized organelle, plays important role in cellular homeostasis. The nuclear proteins are crucial for chromosomal maintenance/segregation, gene expression, RNA processing/export, and many other processes. Several methods have been developed for predicting the nuclear proteins in the past. The aim of the present study is to develop a new method for predicting nuclear proteins with higher accuracy. 相似文献55.
Hemicellulases and auxiliary enzymes for improved conversion of lignocellulosic biomass to monosaccharides 总被引:1,自引:0,他引:1
Dahai Gao Nirmal Uppugundla Shishir PS Chundawat Xiurong Yu Spencer Hermanson Krishne Gowda Phillip Brumm David Mead Venkatesh Balan Bruce E Dale 《Biotechnology for biofuels》2011,4(1):5
Background
High enzyme loading is a major economic bottleneck for the commercial processing of pretreated lignocellulosic biomass to produce fermentable sugars. Optimizing the enzyme cocktail for specific types of pretreated biomass allows for a significant reduction in enzyme loading without sacrificing hydrolysis yield. This is especially important for alkaline pretreatments such as Ammonia fiber expansion (AFEX) pretreated corn stover. Hence, a diverse set of hemicellulases supplemented along with cellulases is necessary for high recovery of monosaccharides. 相似文献56.
L-threose is a product of ascorbate oxidation and degradation. By virtue of its free aldehyde group it can form Schiff-bases with tissue proteins, altering their normal function. In this study, we have examined the possibility of its detoxification to L-threitol by aldose reductase in the lens. The rat lens enzyme present in fresh homogenate as well as after 100 fold purification was found to utilize L-threose with a km of 7.1 × 10–4 M. The specificity of the reaction was affirmed by its inhibition with sorbinil and quercetin, the well known aldose reductase inhibitors. Further studies on the role of this enzyme in preventing toxicity due to degradation products of ascorbate are in progress. 相似文献
57.
58.
With the cancellation of fenamiphos in the near future, alternative nematode management tactics for plant-parasitic nematodes (PPN) on golf courses need to be identified. The use of entomopathogenic nematodes (EPN) has been suggested as one possible alternative. This paper presents the results of 10 experiments evaluating the efficacy of EPN at managing PPN on turfgrasses and improving turf performance. These experiments were conducted at various locations throughout Florida over the course of a decade. In different experiments, different EPN species were tested against different species of PPN. Separate experiments evaluated multiple rates and applications of EPN, compared different EPN species, and compared single EPN species against multiple species of PPN. In a few trials, EPN were associated with reductions in certain plant-parasite species, but in other trials were associated with increases. In most trials, EPN had no effect on plant parasites. Because EPN were so inconsistent in their results, we conclude that EPN are not acceptable alternatives to fenamiphos by most turf managers in Florida at this time. 相似文献
59.
Prevention of lens protein glycation by taurine 总被引:5,自引:0,他引:5
Modifications in lens protein structure and function due to nonenzymic glycosylation and oxidation have been suggested to play a significant role in the pathogenesis of sugar and senile cataracts. The glycation reaction involves an initial Schiff base formation between the protein NH2 groups and the carbonyl group of a reducing sugar. The Schiff base then undergoes several structural modifications, via some oxidative reactions involving oxygen free radicals. Hence certain endogenous tissue components that may inhibit the formation of protein-sugar adduct formation may have a sparing effect against the cataractogenic effects of sugars and reactive oxygen. The eye lens is endowed with significant concentration of taurine, a sulfonated amino acid, and its precursor hypotaurine. It is hypothesized that taurine and hypotaurine may have this purported function of protecting the lens proteins against glycation and subsequent denaturation, in addition to their other functions. The results presented herein suggest that these compounds are indeed capable of protecting glycation competitively by forming Schiff bases with sugar carbonyls, and thereby preventing the glycation of lens proteins per se. In addition, they appear to prevent oxidative damage by scavenging hydroxyl radicals. This was apparent by their preventive effect against the formation of the thiobarbituric acid reactive material generated from deoxy-ribose, when the later was exposed to hydroxyl radicals generated by the action of xanthine oxidase on hypoxanthine in presence of iron. 相似文献
60.
Pyruvate is a well-known scavenger of hydrogen peroxide (H2O2). In addition, it scavenges superoxide radical (O2). However, evidence on its intracellular antioxi-dant function is meager at present. Hence, we have examined the effectivekiess of this metabolite and its ethyl ester against intracellular oxidative damage to the lens under organ culture. Menadione, a redoxcycling quinone, was used to generate the reactive oxygen species (ROS). It was found to inhibit lens metabolism as evidenced by a decrease of ATP. Additionally, tissue oxidation was apparent by loss of glutathione (GSH), and increase in the level of oxidized glutathione (GSSG), coupled with increase of the urea soluble proteins (water insoluble). The overall physiological damage was apparent by the inhibition of the Na+-K+-ATPase dependent cation pump, as evidenced by a decreased rubidium transport. These deleterious effects were attenuated by pyruvate and ethyl-pyruvate. The later was found to be more effective. 相似文献