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21.
Pawlikowska-Pawlega B Gruszecki WI Misiak L Paduch R Piersiak T Zarzyka B Pawelec J Gawron A 《Biochimica et biophysica acta》2007,1768(9):2195-2204
Quercetin is a naturally occurring flavonoid that has a lot of beneficial properties to human health. In this report, using the spin label technique, the influence of quercetin on the fluidity of multilamellar DPPC liposomes was studied. The polarity of the environment preferred by quercetin was also examined by determining the dependence of the position of electronic absorption maxima on dielectric properties of different environments. Autofluorescence of quercetin was also used to examine its distribution in cells. An additional aim of the study was to find how quercetin presence affects human skin fibroblasts. The results showed that incorporation of quercetin at physiological pH into DPPC liposomes caused changes in the partition coefficient of the Tempo spin label between water and polar head group phases. By determining the electronic absorption maxima, we observed that the chromophore of quercetin is localized in the polar head region. Fluorescence microscopy of HSF cells showed quercetin presence in the membrane, cytoplasm and inside the nucleus. Ultrastructural observation revealed some changes, especially in membranous structures, after flavonol treatment. From the results we have concluded that quercetin present in the membrane and other structures can cause changes within cells crucial for its pharmacological activity. 相似文献
22.
Maciej Polak Aleksandra Anna Zasada Ewa Mosiej Katarzyna Krysztopa-Grzybowska Lucjan Witkowski Magdalena Rzeczkowska Katarzyna Piekarska Anna Lutyńska 《Microbes and infection / Institut Pasteur》2019,21(3-4):170-175
The introduction of pertussis vaccination in the 1950s resulted in a significant decrease in the incidence of disease. However, since the 1990s many highly vaccinated countries have observed the re-emergence of the disease. One of the causes of this phenomenon might be related to the adaptation of Bordetella pertussis to vaccination. The purpose of the presented study was an investigation of the emergence and spread of vaccine antigen-deficient B. pertussis isolates in Poland and genomic characterization of the currently circulating pathogen population using PFGE, MLVA and MAST. The results revealed that all tested isolates expressed Ptx, FHA and ACT antigens but 15.4% (4/26) of isolates from 2010 to 2016 were Prn-deficient. Moreover, one TcfA-deficient isolate was collected in 2015. The genotyping showed a genetic distinction between the isolates circulating in 2010–2016 and isolates from previous periods. The majority of currently circulating isolates belonged to PFGE group IV (96.2%), type MT27 (73.1%), and carried ptxA1-ptxC2-ptxP3-prn2-tcfA2-fim2-1-fim3-1 alleles (61.5%). The unique genetic structure of the B. pertussis population in Poland has changed since 2010 and became similar to that observed in countries with aP vaccination. This could be a result of increasing use of aP vaccines (60% of primary vaccination in 2013) over wP vaccines, which have been broadly used for primary vaccination in Poland for decades. 相似文献
23.
Bożena Pawlikowska-Pawlęga Lucjan E. Misiak Anna Jarosz-Wilkołazka Barbara Zarzyka Roman Paduch Antoni Gawron Wieslaw I. Gruszecki 《生物化学与生物物理学报:生物膜》2014
With application of EPR and 1H NMR techniques genistein interaction with liposomes formed with egg yolk lecithin and with erythrocyte membranes was assessed. The present study addressed the problem of genistein localization and its effects on lipid membrane fluidity and protein conformation. The range of microscopic techniques was employed to study genistein effects on HeLa cells and human erythrocytes. Moreover, DPPH bioassay, superoxide anion radical test and enzymatic measurements were performed in HeLa cells subjected to genistein. The gathered results from both EPR and NMR techniques indicated strong ordering effect of genistein on the motional freedom of lipids in the head group region and the adjacent hydrophobic zone in liposomal as well as in red blood cell membranes. EPR study of human ghost showed also the changes in the erythrocyte membrane protein conformation. The membrane effects of genistein were correlated with the changes in internal membranes arrangement of HeLa cells as it was noticed using transmission electron microscopic and fluorescent techniques. Scanning electron and light microscopy methods showed that one of the aftermaths of genistein incorporation into membranes was creation of echinocytic form of the red blood cells with reduced diameter. Genistein improved redox status of HeLa cells treated with H2O2 by lowering radicals' level. 相似文献
24.
The cytomegalovirus (CMV) genome encodes four clusters of genes expressed immediately after infection--i.e.: UL36-38, UL122-123, TRS1-IRS1, and US3. The general function of these genes is associated with inhibition of cellular mechanisms of antiviral response. Although several biological processes have been mapped onto specific gene products, the knowledge of the molecular mechanism of their activity remains fragmentary. Here, we report the application of protein structure prediction methods in assigning the function to a glycosylated domain encoded by UL37 of CMV (gpUL37, UL37x3). The discerned similarity clearly points out that this domain represents a novel type of a major histocompatibility complex (MHC)-like protein, and consequently may play a central role in an additional mechanism of escape from antiviral response. 相似文献
25.
Plewczynski D Tkacz A Wyrwicz LS Rychlewski L Ginalski K 《Journal of molecular modeling》2008,14(1):69-76
We present here the recent update of AutoMotif Server (AMS 2.0) that predicts post-translational modification sites in protein
sequences. The support vector machine (SVM) algorithm was trained on data gathered in 2007 from various sets of proteins containing
experimentally verified chemical modifications of proteins. Short sequence segments around a modification site were dissected
from a parent protein, and represented in the training set as binary or profile vectors. The updated efficiency of the SVM
classification for each type of modification and the predictive power of both representations were estimated using leave-one-out
tests for model of general phosphorylation and for modifications catalyzed by several specific protein kinases. The accuracy
of the method was improved in comparison to the previous version of the service (Plewczynski et al., “AutoMotif server: prediction
of single residue post-translational modifications in proteins”, Bioinformatics 21: 2525–7, 2005). The precision of the updated
version reached over 90% for selected types of phosphorylation and was optimized in trade of lower recall value of the classification
model. The AutoMotif Server version 2007 is freely available at . Additionally, the reference dataset for optimization of prediction of phosphorylation sites, collected from the UniProtKB
was also provided and can be accessed at . 相似文献
26.
Kowalski J Banach M Barylski M Irzmanski R Pawlicki L 《Cellular & molecular biology letters》2008,13(2):230-239
The aim of this study was to evaluate the effect of carvedilol on the enzymatic antioxidative defence and plasma antioxidative
activity in patients with stable angina. The study comprised 30 patients, aged 37–49 years with stable angina. Patients received
carvedilol in escalating doses of 12.5 mg/24 h, 25 mg/24 h, and 50 mg/24 h for 4 weeks each. The control group was matched
for age and gender, and consisted of 12 healthy volunteers, aged 39-49 years. Blood samples were collected from the cubital
vein before and 4, 8 and 12 weeks after the therapy from the patients and once from the control group. For all the subjects,
the superoxide dismutase (SOD-1), glutathione peroxidase (GSH-Px), catalase (CAT) activities in the erythrocytes and the antioxidant
activity of the blood plasma were determined. The enzymatic antioxidative defence was significantly decreased in patients
with stable angina in comparison to the healthy subjects. During the carvedilol therapy, an increase in the SOD-1, GSH-Px
and CAT activities was observed. Moreover, 8 and 12 weeks after carvedilol therapy, the GSH-Px activity did not differ significantly
from that observed in the group of healthy subjects. Carvedilol also increased the plasma antioxidative activity in patients
with stable angina, but its level remained significantly lower than in the control group. In conclusion, carvedilol enhances
antioxidant defense mechanisms in patients with chronic stable angina pectoris. 相似文献
27.
John Sowell Kimberly A. Agnew-Heard J. Christian Mason Charles Mama Lucjan Strekowski Gabor Patonay 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2001,755(1-2)
This paper demonstrates the use of a near-infrared (NIR) dye as a non-covalent label for human serum albumin (HSA). The dye is a water soluble, heptamethine cyanine dye. The utility of the dye as a tracer illustrating the binding of various drugs to HSA is demonstrated via affinity capillary electrophoresis with near-infrared laser-induced fluorescence detection (ACE-NIR-LIF). Additionally, the factors affecting the separation of relevant species were investigated. The change in quantum yield of the dye upon complexation with HSA was calculated. Spectrophotometric measurements were conducted to study the stoichiometry of the dye albumin complex. 相似文献
28.
The heterogeneous nuclear ribonucleoprotein (hnRNP) K homology (KH) domain is an evolutionarily conserved module that binds short ribonucleotide sequences. KH domains most often are present in multiple copies per protein. In vitro studies of hnRNP K and other KH domain bearing proteins have yielded conflicting results regarding the relative contribution of each KH domain to the binding of target RNAs. To assess this RNA-binding we used full-length hnRNP K, its fragments and the yeast ortholog as baits in the yeast three-hybrid system. The results demonstrate that in this heterologous in vivo system, the three KH domains bind RNA synergistically and that a single KH domain, in comparison, binds RNA weakly. 相似文献
29.
Emilia Andrzejewska-Golec Silke Ofterdinger-Daegel Ihsan Calis Lucjan Światek 《Plant Systematics and Evolution》1993,185(1-2):85-89
Within the genusPlantago, subg.Psyllium is characterized by the accumulation of the iridoids plantarenaloside and bartsioside. The latter compound was identified as constituent ofP. sempervirens for the first time. The structures of iridoids were determined by UV, IR,13C-NMR and1H-NMR. Both compounds are of chemotaxonomic value, as they are typical only of subg.Psyllium withinPlantago. The distribution of plantarenaloside within subg.Psyllium suggests the heterogeneity of this taxon. 相似文献
30.
Interaction of unfused tricyclic aromatic cations with DNA: a new class of intercalators 总被引:1,自引:0,他引:1
W D Wilson F A Tanious R A Watson H J Barton A Strekowska D B Harden L Strekowski 《Biochemistry》1989,28(5):1984-1992
Unfused tricyclic aromatic ring systems 1-6 with one or two cationic side chains have been synthesized and their interactions with DNA and synthetic polymers probed with a variety of techniques. Molecular mechanics calculations indicate that the torsional angle between ring planes in the minimum energy conformation of the tricyclic molecules can range from 0 degree to as high as 50 degrees depending on the type of rings and substituents. Viscometric titrations with linear and supercoiled DNA, linear dichroism, and NMR studies indicated that all compounds with torsional angles of approximately 20 degrees or less bind to DNA by intercalation. The more highly twisted intercalators caused significant perturbation of DNA structure. Unfused intercalators with twist angles of approximately 20 degrees have reduced binding constants, suggesting that they could not form an optimum interaction with the DNA base pairs. Unfused intercalators with twist less than 20 degrees formed strong complexes with DNA. The structures of these unfused intercalators are more analogous to typical groove-binding molecules, and an analysis of their interaction with DNA provides a better understanding of the subtle differences between intercalation and groove-binding modes for aromatic cations. The results indicate that intercalation and groove-binding modes should be viewed as two potential wells on a continuous energy surface. The results also suggest design strategies for intercalators that can optimally complement DNA base pair propeller twist or that can induce bends in DNA at the intercalation site. 相似文献