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991.
Structure of two crystal forms of sheep β‐lactoglobulin with EF‐loop in closed conformation 下载免费PDF全文
Joanna I. Loch Marta Molenda Magdalena Kopeć Sylwia Świątek Krzysztof Lewiński 《Biopolymers》2014,101(8):886-894
Ovine β‐lactoglobulin has been isolated from whey fraction of sheep milk and crystallized. The high‐resolution structures of two crystal forms (triclinic and trigonal) obtained at pH 7.0 have been determined revealing that ovine protein, similarly to its bovine analog, is dimeric. Access to the binding site located in the eight‐stranded antiparallel β‐barrel in both structures is blocked by the EF loop that has been found in closed conformation. Similarly to bovine lactoglobulin (BLG), conformation of the EF loop is stabilized by hydrogen bond between Glu89 and Ser116 indicating that Tanford transition might occur with the same mechanism. The substitution at six positions in relation to the most abundant isoform B of BLG also affects the distribution of electrostatic potentials and the total charge. © 2014 Wiley Periodicals, Inc. Biopolymers 101: 886–894, 2014. 相似文献
992.
Aleksandra Markiewicz Magdalena Ksi??kiewicz Marzena We?nicka-Ja?kiewicz Barbara Seroczyńska Jaros?aw Skokowski Jolanta Szade Anna J. ?aczek 《PloS one》2014,9(4)
Introduction
Circulating tumor cells (CTCs) that present mesenchymal phenotypes can escape standard methods of isolation, thus limiting possibilities for their characterization. Whereas mesenchymal CTCs are considered to be more malignant than epithelial CTCs, factors responsible for this aggressiveness have not been thoroughly defined. This study analyzed the molecular profile related to metastasis formation potential of CTC-enriched blood fractions obtained by marker unbiased isolation from breast cancer patients without (N−) and with lymph nodes metastases (N+).Materials and Methods
Blood samples drawn from 117 patients with early-stage breast cancer were enriched for CTCs using density gradient centrifugation and negative selection with anti-CD45 covered magnetic particles. In the resulting CTC-enriched blood fractions, expression of CK19, MGB1, VIM, TWIST1, SNAIL, SLUG, HER2, CXCR4 and uPAR was analyzed with qPCR. Results were correlated with patients'' clinicopathological data.Results
CTCs (defined as expression of either CK19, MGB1 or HER2) were detected in 41% (20/49) of N− and 69% (34/49) of N+ patients (P = 0.004). CTC-enriched blood fractions of N+ patients were more frequently VIM (P = 0.02), SNAIL (P = 0.059) and uPAR-positive (P = 0.03). Positive VIM, CXCR4 and uPAR status correlated with >3 lymph nodes involved (P = 0.003, P = 0.01 and P = 0.045, respectively). In the multivariate logistic regression MGB1 and VIM-positivity were independently related to lymph node involvement with corresponding overall risk of 3.2 and 4.2. Moreover, mesenchymal CTC-enriched blood fractions (CK19−/VIM+ and MGB1+ or HER2+) had 4.88 and 7.85-times elevated expression of CXCR4 and uPAR, respectively, compared with epithelial CTC-enriched blood fractions (CK19+/VIM− and MGB1+ or HER2+).Conclusions
Tumors of N+ patients have superior CTC-seeding and metastatic potential compared with N- patients. These differences can be attributed to VIM, uPAR and CXCR4 expression, which endow tumor cells with particularly malignant phenotypes. 相似文献993.
Aleksandra Biedrzycka Andrzej Zalewski Magdalena Bartoszewicz Henryk Okarma Ewa Jędrzejewska 《Biological invasions》2014,16(8):1611-1625
Invasions of non-native species are of great concern as they have a devastating impact on native biodiversity and can also affect the economy of a region. Multiple introductions in several locations of a new range greatly promote the success of non-native species. The raccoon (Procyon lotor) is an omnivore whose native distribution extends from southern Canada to Panama. It has been successfully introduced in many European countries. We examined the microsatellite and mitochondrial diversity of raccoon populations in Central Europe (Germany, Poland, and Czech Republic) in order to determine their introduction sources and pathways as well as the factors affecting genetic structure in this invasive species. We found low diversity of the mtDNA control region and moderate diversity of microsatellite markers. Raccoon showed three hierarchic levels of genetic structure which separate at different levels sampled from Czech Republic, Germany and raccoon inhabiting two different habitats in Poland. In Poland the raccoon population was established through migration from Germany to Czech Republic. Analysis of the intensity of migration between two different habitat types indicated source-sink dynamics in the Polish populations of raccoons. Our results confirm the high intensity of the raccoon invasion in Central Europe and point to specific measures needed as part of an effective management strategy. 相似文献
994.
995.
Karen Gilio Imke C. A. Munnix Pierre Mangin Judith M. E. M. Cosemans Marion A. H. Feijge Paola E. J. van der Meijden Serv�� Olieslagers Magdalena B. Chrzanowska-Wodnicka Rivka Lillian Simone Schoenwaelder Shigeo Koyasu Stewart O. Sage Shaun P. Jackson Johan W. M. Heemskerk 《The Journal of biological chemistry》2009,284(49):33750-33762
Platelets are activated by adhesion to vascular collagen via the immunoglobulin receptor, glycoprotein VI (GPVI). This causes potent signaling toward activation of phospholipase Cγ2, which bears similarity to the signaling pathway evoked by T- and B-cell receptors. Phosphoinositide 3-kinase (PI3K) plays an important role in collagen-induced platelet activation, because this activity modulates the autocrine effects of secreted ADP. Here, we identified the PI3K isoforms directly downstream of GPVI in human and mouse platelets and determined their role in GPVI-dependent thrombus formation. The targeting of platelet PI3Kα or -β strongly and selectively suppressed GPVI-induced Ca2+ mobilization and inositol 1,4,5-triphosphate production, thus demonstrating enhancement of phospholipase Cγ2 by PI3Kα/β. That PI3Kα and -β have a non-redundant function in GPVI-induced platelet activation and thrombus formation was concluded from measurements of: (i) serine phosphorylation of Akt, (ii) dense granule secretion, (iii) intracellular Ca2+ increases and surface expression of phosphatidylserine under flow, and (iv) thrombus formation, under conditions where PI3Kα/β was blocked or p85α was deficient. In contrast, GPVI-induced platelet activation was insensitive to inhibition or deficiency of PI3Kδ or -γ. Furthermore, PI3Kα/β, but not PI3Kγ, contributed to GPVI-induced Rap1b activation and, surprisingly, also to Rap1b-independent platelet activation via GPVI. Together, these findings demonstrate that both PI3Kα and -β isoforms are required for full GPVI-dependent platelet Ca2+ signaling and thrombus formation, partly independently of Rap1b. This provides a new mechanistic explanation for the anti-thrombotic effect of PI3K inhibition and makes PI3Kα an interesting new target for anti-platelet therapy. 相似文献
996.
Agnieszka Bajda Dorota Konopka-Postupolska Magdalena Krzymowska Jacek Hennig Karolina Skorupinska-Tudek Liliana Surmacz Jacek Wójcik Zdzislaw Matysiak Tadeusz Chojnacki Ewa Skorzynska-Polit Maria Drazkiewicz Pawel Patrzylas Monika Tomaszewska Magdalena Kania Malgorzata Swist Witold Danikiewicz Wieslawa Piotrowska and Ewa Swiezewska 《Physiologia plantarum》2009,135(4):351-364
Infection with avirulent pathogens, tobacco mosaic virus (TMV) or Pseudomonas syringae pv. tabaci induced accumulation of polyisoprenoid alcohols, solanesol and a family of polyprenols [from polyprenol composed of 14 isoprene units (Pren-14) to -18, with Pren-16 dominating] in the leaves of resistant tobacco plants Nicotiana tabacum cv. Samsun NN. Upon TMV infection, solanesol content was increased seven- and eight-fold in the inoculated and upper leaves, respectively, while polyprenol content was increased 2.5- and 2-fold in the inoculated and upper leaves, respectively, on the seventh day post-infection. Accumulation of polyisoprenoid alcohols was also stimulated by exogenously applied hydrogen peroxide but not by exogenous salicylic acid (SA). On the contrary, neither inoculation of the leaves of susceptible tobacco plants nor wounding of tobacco leaves caused an increase in polyisoprenoid content. Taken together, these results indicate that polyisoprenoid alcohols might be involved in plant resistance against pathogens. A putative role of accumulated polyisoprenoids in plant response to pathogen attack is discussed. Similarly, the content of plastoquinone (PQ) was increased two-fold in TMV-inoculated and upper leaves of resistant plants. Accumulation of PQ was also stimulated by hydrogen peroxide, bacteria ( P. syringae ) and SA. The role of PQ in antioxidant defense in cellular membranous compartments is discussed in the context of the enzymatic antioxidant machinery activated in tobacco leaves subjected to viral infection. Elevated activity of several antioxidant enzymes (ascorbate peroxidase, guaiacol peroxidase, glutathione reductase and superoxide dismutase, especially the CuZn superoxide dismutase isoform) and high, but transient elevation of catalase was found in inoculated leaves of resistant tobacco plants but not in susceptible plants. 相似文献
997.
Véronique Gosselain Michel Coste Stéphane Campeau Luc Ector Claude Fauville François Delmas Markus Knoflacher Magdalena Licursi Frédéric Rimet Juliette Tison Loïc Tudesque Jean-Pierre Descy 《Hydrobiologia》2005,542(1):151-163
A relational database linking benthic diatom records, taxonomic nomenclature including synonyms, and corresponding environmental
data has been built in MS Access. It allowed flexible and long-term use of a relatively important amount of data (∼3000 records)
gathered in the framework of the EC-funded PAEQANN project, gathering precise and documented information both about benthic
diatoms and quantitative or semi-quantitative environmental data. Such a database has been shown to be a useful tool for the
definition of benthic diatom typology at a multi-regional scale, the prediction of the impact of environmental characteristics
on the structure of diatom communities, and additionally for a new insight on the auto-ecology of some taxa. This database
could serve as a template for further work on diatoms and, after some implementation, on other freshwater communities. It
could also be the basis for wider typology of stream diatoms, extended to other regions. 相似文献
998.
Sokolowska-Mikolajczyk M Socha M Mikolajczyk T Chyb J Szymacha J Epler P 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2005,141(4):325-331
The in vitro effects of morphine (10(-10), 10(-8), 10(-6) or 10(-5) M) or/and naltrexone (10(-6) or 10(-8) M) on LH release from male and female carp (Cyprinus carpio L.) dispersed pituitary cells (obtained from fish at the time of late gonad recrudescence) were investigated. Morphine alone at the lowest tested concentration (10(-10) M) increased LH secretion from the cells of males. On the contrary, in female cell incubations the highest concentrations of morphine (10(-6) or 10(-5) M) significantly lowered LH levels. Naltrexone alone (at both tested concentrations) had no influence on LH secretion, neither in males nor in females. However in the incubations of female cells it antagonised the influence of morphine at 10(-10) or 10(-8) M. In male cell incubations naltrexone abolished the stimulatory action of morphine at 10(-10) M. The results suggest that in the in vitro culture of carp pituitary cells LH secretion is modulated by the opioids which affect the release of this gonadotropin through the typical opioid receptors and that the mu type of these receptors is involved in this process. The effects of opioid agonist and antagonist depend on the stage of gonadal maturity and the sex of fish i.e. the actual level of sex steroids. 相似文献
999.
Adam Mieczkowski Mateusz Psurski Maciej Bagiński Bartosz Bieszczad Magdalena Mroczkowska Marcin Wilczek Joanna Czajkowska Damian Trzybiński Krzysztof Woźniak Joanna Wietrzyk 《Bioorganic & medicinal chemistry letters》2018,28(4):618-625
A series of optically pure (R)- and (S)-1,3,4,12a-tetrahydropyrazino[2,1-c][1,4]benzodiazepine-6,12(2H,11H)-dione derivatives was designed and synthesized as novel anthramycin analogues in a three-step, one-pot procedure, and tested for their antiproliferative activity on nine following cell lines: MV-4-11, UMUC-3, MDA-MB-231, MCF7, LoVo, HT-29, A-549, A2780 and BALB/3T3. The key structural features responsible for exhibition of cytotoxic effect were determined: the (S)-configuration of chiral center and the presence of hydrophobic 4-biphenyl substituent in the side chain. Introduction of bromine atom into the 8 position (8g) or substitution of dilactam ring with benzyl group (8m) further improved the activity and selectivity of investigated compounds. Among others, compound 8g exhibited selective cytotoxic effect against MV-4-11 (IC50?=?8.7?μM) and HT-29 (IC50?=?17.8?μM) cell lines, while 8m showed noticeable anticancer activity against MV-4-11 (IC50?=?10.8?μM) and LoVo (IC50?=?11.0?μM) cell lines. The cell cycle arrest in G1/S checkpoint and apoptosis associated with overproduction of reactive oxygen species was also observed for 8e and 8m. 相似文献
1000.