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181.
Pavel Vesely Luboslava Pavlikova Jiri Plachy Katerina Trejbalova Jiri Hejnar Eva Matouskova Jürgen Bereiter-Hahn 《Experimental Biology Online》1997,2(6):1-74
In spontaneously metastasizing rat RPS sarcoma cells, a 3D structure of oblique F-actin cables was observed which was associated with active cell migration in vitro. This led us to further comparative investigations of several other neoplastic and normal cell populations in vitro for F-actin structures using confocal laser scanning microscopy (CLSM). Various forms of F-actin cytoskeleton were observed and the incidence of podosome-related contact structures appeared to be associated with malignancy, interpreted as metastatic capacity. 相似文献
182.
Koen Uytterhoeven Jiri Sponer Luc Van Meervelt 《European journal of biochemistry》2002,269(12):2868-2877
Single-crystal X-ray structure determinations of the complex between the minor-groove binder distamycin and d(GGCCAATTGG) reveal two 1 : 1 binding modes which differ in the orientation of the drug molecule in the minor groove. The two crystals were grown from different crystallization conditions and found to diffract to 2.38 and 1.85 A, respectively. The structures were refined to completion using SHELXL-93, resulting in a residual R factor of 20.30% for the 2.38-A resolution structure (including 46 water molecules) and 19.74% for the 1.85-A resolution structure (including 74 water molecules). In both orientations, bifurcated hydrogen bonds are formed between the amide nitrogen atoms of the drug and AT base pairs. With a binding site of at least five base pairs, close contacts between the terminal distamycin atoms and guanine amino groups are inevitable. The detailed nature of several of these interactions was further investigated by ab initio quantum chemical methods. 相似文献
183.
David W. Macdonald Paul D. Stewart Paul J. Johnson Jiri Porkert & Christina Buesching 《Ethology : formerly Zeitschrift fur Tierpsychologie》2002,108(7):613-628
Linear or despotic dominance hierarchies are common in carnivore societies. However, in feeding experiments in the field with wild European badgers, Meles meles, we found no compelling evidence for any such hierarchies within badger groups, or even between the members of neighbouring groups. The outcome of dyadic encounters within groups was partly determined by asymmetries in weight and length, but these predictors were readily confounded by ownership. Aggression between members of neighbouring groups during encounters at feeding sites at territorial borders was extremely rare. These rather ad hoc aspects of social organization reinforce the view that badger societies are somewhat loosely structured. 相似文献
184.
Huan H. Nguyen Prosper N. Boyaka Zina Moldoveanu Miroslav J. Novak Hiroshi Kiyono Jerry R. McGhee Jiri Mestecky 《Journal of virology》1998,72(5):4534-4536
We have investigated the mechanisms involved in the clearance of viral infection at the epithelium level by analyzing the activity of influenza virus-specific cytotoxic T lymphocytes (CTL) against virus-infected CMT-93 intestinal epithelial cells. Epithelial cells infected with live influenza virus effectively present viral antigens and were lysed by both homotypic and heterotypic influenza virus-specific CD8+ T cells. These results shed new light on the control of viral infection through the elimination of virus-infected epithelial cells by virus-specific CTL and demonstrate that CMT-93 cells furnish an appropriate model for in vitro evaluation of CTL activity against virus-infected epithelial cells. 相似文献
185.
The physiological role of monocarboxylate transport in brownadipose tissue mitochondria has been reevaluated. We studied pyruvate,-ketoisovalerate, -ketoisocaproate, and phenylpyruvate uniportvia the uncoupling protein (UCP1) as a GDP-sensitive swelling inK+ salts induced by valinomycin orby monensin and carbonylcyanide-p-(trifluoromethoxy)phenylhydrazone in Na+ salts. We have demonstratedthat this uniport is inhibited by fatty acids. GDP inhibition inK+ salts was not abolished by anuncoupler, indicating a negligible monocarboxylic acid penetration viathe lipid bilayer. In contrast, the electroneutral pyruvate uptake(swelling in ammonium pyruvate or potassium pyruvate induced by changein pH) mediated by the pyruvate carrier was inhibited by its specificinhibitor -cyano-4-hydroxycinnamate but not by fatty acids.Moreover, -cyano-4-hydroxycinnamate enhanced the energization ofbrown adipose tissue mitochondria, which was monitored fluorometricallyby 2-(4-dimethylaminostyryl)-1-methylpyridinium iodide and safranin O. Consequently, we suggest that UCP1 might participate in futile cyclingof unipolar ketocarboxylates under certain physiological conditionswhile expelling these anions from the matrix. The cycle is completed ontheir return via the pyruvate carrier in anH+ symport mode. 相似文献
186.
Selective extraction of polymers from cell walls of Gram-positive bacteria (Short Communication)
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Brief heating of Bacillus Licheniformis cell walls at 100 degrees C in aqueous buffers of pH3.0-4.0 removes some polymers but not others from the mucopeptides. For example, relatively undegraded teichuronic acid can be extracted at 100 degrees C in 20min at pH3.0 whereas the teichoic acids are not removed. Similar specificity can be shown with walls from three other species of micro-organism. 相似文献
187.
188.
Procházka L Turánek J Tesarík R Knotigová P Polásková P Andrysík Z Kozubík A Zák F Sova P Neuzil J Machala M 《Archives of biochemistry and biophysics》2007,462(1):54-61
A new hydrophobic platinum(IV) complex, LA-12, a very efficient anticancer drug lacking cross-resistance with cisplatin (CDDP), is now being tested in clinical trials. Here we investigated the apoptogenic activity of LA-12 and its effect on gap-junctional intercellular communication (GJIC) in the rat liver epithelial cell line WB-F344. LA-12 induced apoptosis much more efficiently than did CDDP due to a combination of rapid penetration into the cell and attack on DNA, leading to fast activation of p53 and caspase-3. Exposure of WB-F344 cells to LA-12 led to rapid induction of the time- and dose-dependent decrease in GJIC. On the molecular level, loss of GJIC induced by LA-12 was mediated by activation of extracellular signal-regulated kinase (ERK)-1 and ERK-2, as demonstrated by the use of inhibitors of ERK activation. Inhibition of GJIC was linked to rapid hyperphosphorylation of connexin-43 and disappearance of connexon clusters from membranes, which was not observed in the case of CDDP. 相似文献
189.
Kotik Michael Vanacek Pavel Kunka Antonin Prokop Zbynek Damborsky Jiri 《Applied microbiology and biotechnology》2017,101(16):6385-6397
Applied Microbiology and Biotechnology - Haloalkane dehalogenases (HLDs) are environmentally relevant enzymes cleaving a carbon-halogen bond in a wide range of halogenated pollutants. PCR with... 相似文献
190.
Ivana Tomaskova Vaclav Bazant Roman Bleha Jan Vitamvas Sylvain Delzon Karel Stastny Jiri Vackar 《Contemporary Problems of Ecology》2017,10(2):193-202
Four tree species in the Kostelec n. ?. l. arboretum (Czech Republic) have been repeatedly damaged by Dendrocopos medius. The unique aspect of this otherwise common behavior called girdling consists in regularly visiting the same trees every spring, although there are more than 1.200 tree species within the arboretum. We monitored transpiration, leaf phenology and the chemical composition of the xylem sap of girdled and nongirdled trees. Spectral analysis revealed slightly higher amounts of sugars, especially saccharose, in Cladrastis Raf. as the most regularly girdled tree among other conditions, comparing girdled to non-girdled trees. Higher transpiration rates were not confirmed in connection with girdling—quite the opposite—Cladrastis Raf. as the most highly favored tree for girdling showed the lowest transpiration rates (in average 6 kg water per day within spring months) compared to other non-girdled trees. We presume that the birds do not choose a particular tree on the basis of any visible or chemical traits but they examine many trees within their territory. Afterwards they probably remember the position of trees whose xylem sap starts to flow early in the spring compared to other trees, as their transpiration stream is enriched with sweet organic substances that represent an advantage for the forthcoming nesting period. 相似文献