Palacki University

Olomouc, Czech Republic

Palacki University

Olomouc, Czech Republic
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Ghanem M.E.,Catholic University of Leuven | Albacete A.,CSIC - Center of Edafology and Applied Biology of the Segura | Albacete A.,University of Graz | Smigocki A.C.,U.S. Department of Agriculture | And 9 more authors.
Journal of Experimental Botany | Year: 2011

Salinity limits crop productivity, in part by decreasing shoot concentrations of the growth-promoting and senescence-delaying hormones cytokinins. Since constitutive cytokinin overproduction may have pleiotropic effects on plant development, two approaches assessed whether specific root-localized transgenic IPT (a key enzyme for cytokinin biosynthesis) gene expression could substantially improve tomato plant growth and yield under salinity: transient root IPT induction (HSP70::IPT) and grafting wild-type (WT) shoots onto a constitutive IPT-expressing rootstock (WT/35S::IPT). Transient root IPT induction increased root, xylem sap, and leaf bioactive cytokinin concentrations 2- to 3-fold without shoot IPT gene expression. Although IPT induction reduced root biomass (by 15%) in control (non-salinized) plants, in salinized plants (100mM NaCl for 22d), increased cytokinin concentrations delayed stomatal closure and leaf senescence and almost doubled shoot growth (compared with WT plants), with concomitant increases in the essential nutrient K+ (20%) and decreases in the toxic ion Na+ (by 30%) and abscisic acid (by 20-40%) concentrations in transpiring mature leaves. Similarly, WT/35S::IPT plants (scion/rootstock) grown with 75mM NaCl for 90d had higher fruit trans-zeatin concentrations (1.5- to 2-fold) and yielded 30% more than WT/non-transformed plants. Enhancing root cytokinin synthesis modified both shoot hormonal and ionic status, thus ameliorating salinity-induced decreases in growth and yield. © 2010 The Author.

Liu J.-L.,Sun Yat Sen University | Bao X.,Sun Yat Sen University | Herchel R.,Palacki University | Leng J.-D.,Sun Yat Sen University | And 2 more authors.
Australian Journal of Chemistry | Year: 2010

Two ideal triangular Ni3 compounds [Ni3( 1,3-N3)3(2,2′-bpy)3]X 33H2O (X ≤ ClO4 - (1) and BF 4 - (2); 2,2′-bpy ≤ 2,2′-bipyridine) have, for the first time, been structurally and magnetically characterized, and represent a good model for us to understand the magnetic behaviours in extended azide-bridged nickel(II) complexes with trinuclear subunits. © 2010 CSIRO.

Reifova R.,Charles University | Reif J.,Charles University | Reif J.,Palacki University | Antczak M.,Adam Mickiewicz University | Nachman M.W.,University of Arizona
BMC Evolutionary Biology | Year: 2011

Abstract. Background: Ecological character displacement is a process of phenotypic differentiation of sympatric populations caused by interspecific competition. Such differentiation could facilitate speciation by enhancing reproductive isolation between incipient species, although empirical evidence for it at early stages of divergence when gene flow still occurs between the species is relatively scarce. Here we studied patterns of morphological variation in sympatric and allopatric populations of two hybridizing species of birds, the Common Nightingale (Luscinia megarhynchos) and the Thrush Nightingale (L. luscinia). Results: We conducted principal component (PC) analysis of morphological traits and found that nightingale species converged in overall body size (PC1) and diverged in relative bill size (PC3) in sympatry. Closer analysis of morphological variation along geographical gradients revealed that the convergence in body size can be attributed largely to increasing body size with increasing latitude, a phenomenon known as Bergmann's rule. In contrast, interspecific interactions contributed significantly to the observed divergence in relative bill size, even after controlling for the effects of geographical gradients. We suggest that the divergence in bill size most likely reflects segregation of feeding niches between the species in sympatry. Conclusions: Our results suggest that interspecific competition for food resources can drive species divergence even in the face of ongoing hybridization. Such divergence may enhance reproductive isolation between the species and thus contribute to speciation. © 2011 Reifová et al; licensee BioMed Central Ltd.

Ding Z.,Ghent University | Ding Z.,Shandong University | Wang B.,University of Fribourg | Moreno I.,Andrés Bello University | And 19 more authors.
Nature Communications | Year: 2012

Auxin is a key coordinative signal required for many aspects of plant development and its levels are controlled by auxin metabolism and intercellular auxin transport. Here we find that a member of PIN auxin transporter family, PIN8 is expressed in male gametophyte of Arabidopsis thaliana and has a crucial role in pollen development and functionality. Ectopic expression in sporophytic tissues establishes a role of PIN8 in regulating auxin homoeostasis and metabolism. PIN8 co-localizes with PIN5 to the endoplasmic reticulum (ER) where it acts as an auxin transporter. Genetic analyses reveal an antagonistic action of PIN5 and PIN8 in the regulation of intracellular auxin homoeostasis and gametophyte as well as sporophyte development. Our results reveal a role of the auxin transport in male gametophyte development in which the distinct actions of ER-localized PIN transporters regulate cellular auxin homoeostasis and maintain the auxin levels optimal for pollen development and pollen tube growth. © 2012 Macmillan Publishers Limited. All rights reserved.

Ibrahimi M.H.,University of Tirana | Papajani V.,University of Tirana | Zeljkovic S.C.,Palacki University | Matevski V.,Ss. Cyril and Methodius University of Skopje
Journal of Essential Oil-Bearing Plants | Year: 2014

Abstract: Thymus jankae Cel. and Thymus pulegioides L. subsp. montanus (W.K.) Ronn growing wild in Kosovo have been analyzed for their volatile chemical profile using GC-MS technique. The essential oil of the plants was obtained by hydrodistillation with Clevenger apparatus. Essential oil of two samples of T. jankae Cel. resulted with yields of 0.60 % and 0.72 % respectively, while T. pulegioides L. essential oil yield was 1.58 % on dried weight. Exactly fifty-eight compounds were identified in all three samples. Two chemotypes resulted from the studied T. jankae Cel. essential oil samples: thymol chemotype with 45.78 % of thymol, and β-caryophyllene/caryophyllene oxide chemotype, with 33.25 % and 21.83 %, respectively. The chemical profile of the essential oil sample of T. pulegioides L. resulted with geraniol as the main constituent, with 34.52 % in total. Presented results confirm the influence of environmental and phenological conditions on the chemical composition. © 2014, © 2014 Har Krishan Bhalla & Sons.

Soural M.,Palacki University | Hlavac J.,Palacki University | Funk P.,Palacki University | D-ubak P.,Palacki University | Hajd-ch M.,Palacki University
ACS Combinatorial Science | Year: 2011

A structure-activity relationship of some derivatives of 2-phenylsubstituted- 3-hydroxyquinolin-4(1H)-one-7-carboxamides was systematically studied using combinatorial solid-phase synthesis and in vitro cytotoxic activity screening on representative cancer lines. The effect of substituent type in position 2 as well as of the carboxamide group was investigated via synthesis of generic libraries constructed with respect to polarity and bulkiness of appropriate substituents. The process of development afforded a set of compounds with significant cytotoxic activity. Subsequently, corresponding 2-phenylsubstituted-3-hydroxyquinolin-4(1H)-one-6-carboxamides and 2-phenylsubstituted-3-hydroxyquinolin-4(1H)-one-8-carboxamides were prepared to evaluate the influence of the carboxamide group position on the resulting biological activity. © 2010 American Chemical Society.

Rac M.,Palacki University | Sedlaova M.,Palacki University | Pospisil P.,Palacki University
Scientific Reports | Year: 2015

In this study, evidence is provided on the formation of electronically excited species in human multiple myeloma cells U266 in the growth medium exposed to hydrogen peroxide (H2O2). Two-dimensional imaging of ultra-weak photon emission using highly sensitive charge coupled device camera revealed that the addition of H2O2 to cell suspension caused the formation of triplet excited carbonyls 3(R = O)∗. The kinetics of 3(R = O)∗ formation in the real time, as measured by one-dimensional ultra-weak photon emission using low-noise photomultiplier, showed immediate enhancement followed by a slow decay. In parallel to the formation of 3 (R = O)∗, the formation of singlet oxygen (1O2) in U266 cells caused by the addition of H2O2 was visualized by the imaging of 1O2 using the green fluorescence of singlet oxygen sensor green detected by confocal laser scanning microscopy. Additionally, the formation of 1O2 after the addition of H2O2 to cell suspension was detected by electron paramagnetic resonance spin-trapping spectroscopy using 2,2,6,6-tetramethyl-4-piperidone. Presented results indicate that the addition of H2O2 to cell suspension results in the formation of 3(R = O)∗ and 1O2 in U266 cell suspension. The contribution of the cell-free medium to the formation of electronically excited species was discussed.

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