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International Journal of Electrochemical Science
Electrochemical behaviour of apoferritin encapsulating of silver(I) ions and its application for treatment of Staphylococcus aureus
Dospivová, D.; Hynek, D.; Kopel, P.; Bezděková, A.; Sochor, J.; Křížková, S.; Adam, V.; Trnková, L.;Hubálek, J.;Babula, P.; Provazník, I.; Vrba, R.;Kizek, R.
CEITEC Research Group: Submicron Systems and Nanodevices
Research Programme 1: Advanced Nanotechnologies and Microtechnologies
Summary
Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for several difficult-to-treat infections in humans. Therefore, it is not surprising that other ways how to treat these bacteria are looked for. Silver(I) ions and silver nanoparticles exhibited the highest antimicrobial activity against MRSA but their transporting to the place of needs and in situ determination is an issue. The aim of this work was electrochemical determination of silver(I) ions using four types of modified carbon paste electrodes (CPEs) with different content of carbon nanoparticles. CPE made from expanded carbon was the most sensitive one. Therefore, we optimized the experimental conditions as time of accumulation 60 s, deposition potential 0.5 V and 0.2 M acetate buffer, pH = 5.0 to obtain detection limit (3 S/N) of 5 nM for silver(I) ions. Further, we studied the encapsulation of silver(I) ions into apoferritin as a possible way for transportation of these ions. Primarily we optimized the encapsulation conditions to prepare the most stable complex, which was subsequently utilized for treatment of S. aureus. Based on the results obtained it can be concluded that silver(I) ions remain enclosed in the apoferritin structure until decomposition of apoferritin by bacterial enzymatic apparatus occurs.
Spectrochimica Acta Part B
Application of laser-induced breakdown spectroscopy to the analysis of algal biomass for industrial biotechnology
Pořízka, P.; Prochazka, D.; Pilát, Z.; Krajcarová, L.;Kaiser, J.; Malina, R.; Novotný, J.; Zemánek, P.; Ježek, J.; Šerý, M.; Bernatová, S.; Krzyžánek, V.; Dobranská, K.; Novotný, K.; Trtílek, M.; Samek, O.
CEITEC Research Group: X-ray Micro CT and Nano CT
Research Programme 1: Advanced Nanotechnologies and Microtechnologies
Summary
We report on the application of laser-induced breakdown spectroscopy (LIBS) to the determination of elements distinctive in terms of their biological significance (such as potassium, magnesium, calcium, and sodium) and to the monitoring of accumulation of potentially toxic heavy metal ions in living microorganisms (algae), in order to trace e.g. the influence of environmental exposure and other cultivation and biological factors having an impact on them. Algae cells were suspended in liquid media or presented in a form of adherent cell mass on a surface (biofilm) and, consequently, characterized using their spectra. In our feasibility study we used three different experimental arrangements employing double-pulse LIBS technique in order to improve on analytical selectivity and sensitivity for potential industrial biotechnology applications, e.g. for monitoring of mass production of commercial biofuels, utilization in the food industry and control of the removal of heavy metal ions from industrial waste waters.
Journal of the American Ceramic Society
Optimization of Fine Alumina Gelcasting Using In Situ Dynamic Rheology
Bera, O.; Trunec, M.
CEITEC Research Group: Advanced Ceramics Materials
Research Programme 2: Advanced Materials
Summary
In situ dynamic rheology was used to investigate the polymerization process of gelcasting suspensions based on fine alumina and water solution of methacrylamide and methylene bisacrylamide monomers. Small-strain oscillatory shear measurements were able to detect the progress of the whole gelation process from the liquid suspension to the elastic gel. The parameters describing the gelation kinetics and final gel properties such as idle time, total gelation time, and equilibrium complex viskosity were correlated with the initiator/accelerator concentration, linear to cross-linking monomer ratio, polymerization temperature, and alumina loading. A strong catalytic effect of fine alumina particles on the decomposition of ammonium persulfáte into free radicals was established. The catalytic activity of alumina powder was controlled by ions adsorbed on the partije surface. The catalytic effect of alumina in the presence of the Dolapix CE 64 dispersant made the polymerization process independent of the accelerator concentration and enabled the gelation of concentrated ceramic suspensions at and below room temperature without any accelerator. The variations of the polymerization process in the range of investigated gel compositions did not affect the particle packing in green bodls and the densities of sintered ceramic bodies were similar.
Journal of Physics: Condensed Matter
Dynamic stability of fcc crystals under isotropic loading from first principles
Řehák, P.; Černý, M.; Pokluda, J.
CEITEC Research Group: Advanced Metallic Materials and Metal Based Composited
Research Programme 2: Advanced Materials
Summary
Lattice dynamics and stability of four fcc crystals (Al, Ir, Pt and Au) under isotropic (hydrostatic) tensile loading are studied from first principles using the linear response method and the harmonic approximation. The results reveal that, contrary to former expectations, strengths of all the studied crystals are limited by instabilities related to soft phonons with finite or vanishing wavevectors. The critical strains associated with such instabilities are remarkably lower than those related to the volumetric instability. On the other hand, the corresponding reduction of the tensile strength is by 20% at the most. An analysis of elastic stability conditions is also performed and the results obtained by means of both approaches are compared.
Nucleic Acids Research
Polymorphism of human telomeric quadruplex structure controlled by DNA concentration: A Raman study
Palacky, J.; Vorlickova, M.; Kejnovska, I.; Mojzes, P.
CEITEC Research Group: CD Spectroscopy of Nucleic Acids and Proteins
Research Programme 3: Structural Biology
Summary
DNA concentration has been recently suggested to be the reason why different arrangements are revealed for K+-stabilized human telomere quadruplexes by experimental methods requiring DNA concentrations differing by orders of magnitude. As Raman spectroscopy can be applied to DNA samples ranging from those accessible by absorption and CD spectroscopies up to extremely concentrated solutions, gels and even crystals; it has been used here to clarify polymorphism of a core human telomeric sequence G3(TTAG3)3 in the presence of K+ and Na+ ions throughout wide range of DNA concentrations. We demonstrate that the K+-structure of G3(TTAG3)3 at low DNA concentration is close to the antiparallel fold of Na+-stabilized quadruplex. On the increase of G3(TTAG3)3 concentration, a gradual transition from antiparallel to intramolecular parallel arrangement was observed, but only for thermodynamically equilibrated K+-stabilized samples. The transition is synergically supported by increased K+ concentration. However, even for extremely high G3(TTAG3)3 and K+ concentrations, an intramolecular antiparallel quadruplex is spontaneously formed from desalted non-quadruplex single-strand after addition of K+ ions. Thermal destabilization or long dwell time are necessary to induce interquadruplex transition. On the contrary, Na+ stabilized G3(TTAG3)3 retains its antiparallel folding regardless of the extremely high DNA and/or Na+ concentrations, thermal destabilization or annealing.
PLoS Computational Biology
Charge Profile Analysis Reveals That Activation of Pro-apoptotic Regulators Bax and Bak Relies on Charge Transfer Mediated Allosteric Regulation
Ionescu, C.M.; Svobodova Varekova, R.; Prehn, J.H.M.; Huber, H.J.;Koca J.
CEITEC Research Group: Computational Chemistry
Research Programme 3: Structural Biology
Summary
Apoptosis is a physiological form of cell death that is fundamental for development, growth and homeostasis in multi-cellular organisms. Deviations in the apoptosis machinery are known to be involved in cancer, neurodegenerative disorders, and autoimmune diseases. The proteins Bax and
Bak are essential for executing apoptosis, yet the mechanism of their activation is not properly understood at the structural level. In order to understand this mechanism, we developed a straightforward and accessible methodology based on the estimation of atomic partial charges and subsequently inter- and intra-molecular charge transfer. This methodology allows to identify the key residues involved in the fast activation of proteins during signal transduction. We thus were able to identify the specific interactions responsible for the exposure of the functional sites of Bax upon binding of an activator peptide. These sites are present also in Bak, and represent potential drug targets.
Mandáková T., Mummenhoff K., Al-Shehbaz I.A., Mucina L., Mühlhausen A., Lysak M.A.
CEITECResearch Group: Plant Cytogenomics
Research Programme 4: Genomics and proteomics of plant systems
Summary
The unigeneric tribe Heliophileae includes ca. 90Heliophila species, all endemic to southern Africa. The tribe ismorphologically the most diverse crucifer lineage in every aspect of habit, foliage, flower and fruit morphology. Despite this diversity, virtually nothing was known about its origin and genome evolution. Comparative chromosome painting analyses in several species with different chromosome number revealed that all Heliophila species, and probably the entire tribe Heliophileae, experienced an ancient whole-genome triplication (WGT) event. The WGT has been followed by chromosome rearrangements resulting in species-specific reduction of chromosome numbers towards extant quasi-diploid genomes (diploidization process). The WGT might have contributed to diversification and species radiation in Heliophileae. To our knowledge, this is the first study to document polyploidy as a potential major mechanism for the radiation of a Cape plant lineage.
Plant Cell
Spatiotemporal Regulation of Lateral Root Organogenesis in Arabidopsis by Cytokinin
Bielach A., Podlešáková K., Marhavý P., Duclercq J., Cuesta C., Müller B., Grunewald W., Tarkowski P., Benková E.,
CEITEC Research Group:Hormonal Crosstalk in Plant Development
Research Programme 4: Genomics and Proteomics of Plant Systems
Summary
The architecture of a plant’s root system, established postembryonically, results from both coordinated root growth and lateral root branching. The plant hormones auxin and cytokinin are central endogenous signaling molecules that regulate lateral root organogenesis positively and negatively, respectively. Tight control and mutual balance of their antagonistic activities are particularly important during the early phases of lateral root organogenesis to ensure continuous lateral root initiation (LRI) and proper development of lateral root primordia (LRP). Here, we show that the early phases of lateral root organogenesis, including priming and initiation, take place in root zones with a repressed cytokinin response. Accordingly, ectopic overproduction of cytokinin in the root basal meristem most efficiently inhibits LRI. Enhanced cytokinin responses in pericycle cells between existing LRP might restrict LRI near existing LRP and, when compromised, ectopic LRI occurs.
Experimental Hematology
Gene expression profiling of acute graft-vs-host disease after hematopoietic stem cell transplantation
Verner, J.; Kabathova, J.; Tomancova, A.; Pavlova, S.; Tichy, B.; Mraz, M.; Brychtova, Y.; Krejci, M.; Zdrahal, Z.; Trbusek, M.; Volejnikova, J.; Sedlacek, P.; Doubek, M.; Mayer, J., Pospisilova, S.
CEITEC Research Group: Medical Genomics
Research Programme 5: Molecular Medicine
Summary
Acute graft-vs-host disease (aGVHD) is a frequent, life-threating complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Despite that, there are no reliable molecular markers reflecting the onset or clinical course of aGVHD. We performed a pilot study on gene expression profiling in peripheral blood mononuclear cells taken from 15 patients with haematological malignancies who underwent allo-HSCT and developed aGVHD. Based on survival rates after aGVHD, patients were divided into two groups – favourable (all patients alive; median follow-up 40 months) vs unfavourable group (all patients died; median survival 2 months). Two-hundred and eighty genes differentially expressed between these two groups were identified; among them, genes responsible for cytokine signalling, inflammatory response, and regulation of cell cycle were over-represented; interleukin-8, G0S2, ANXA3, and NR4A2 were upregulated in the unfavourable group, CDKN1C was downregulated in the same group. Interestingly, the same genes were also described as overexpressed in connection with autoimmune diseases. This indicates an involvement of similar immune regulatory pathways also in aGVHD. Our data support use of gene expression profiling at aGVHD onset for a prediction of its outcomes.
Cell Division
Cyclin K goes with Cdk12 and Cdk13
Kohoutek, J.,Blazek, D.
CEITEC Research Group: Inherited Diseases II – Transcriptional Regulation
Research Programme 5:Molecular Medicine
Summary
The cyclin-dependent kinases (Cdks) regulate many cellular processes, including the cell cycle, neuronal development, transcription, and posttranscriptional processing. To perform their functions, Cdks bind to specific cyclin subunits to form a functional and active cyclin/Cdk complex. This review is focused on Cyclin K, which was originally considered an alternative subunit of Cdk9, and on its newly identified partners, Cdk12 and Cdk13. We briefly summarize research devoted to each of these proteins. We also discuss the proteins’ functions in the regulation of gene expression via the phosphorylation of serine 2 in the C-terminal domain of RNA polymerase II, contributions to the maintenance of genome stability, and roles in the onset of human disease and embryo development.
The International Journal of Neuropsychopharmacology
The effects of methamphetamine self-administration on behavioural sensitization in the olfactory bulbectomy rat model of depression
Kucerova, J.; Pistovcakova, J.; Vrskova, D.; Dusek, L.; Sulcova, A.
CEITEC Research Group: Experimental and Applied Neuropsychopharmacology
Research Programme 6: Brain and mind research
Summary
In this study the effect of repeated administration of methamphetamine on i.v. drug self-administration in an olfactory bulbectomy model of depression in rats was investigated in order to propose and validate a rat model of comorbid depression and addiction.
Exp Brain Res – Experimental Brain Research
The role of the right dorsolateral prefrontal cortex in the Tower of London task performance: repetitive transcranial magnetic stimulation study in patients with Parkinson’s disease.
Srovnalova H., Marecek R., Kubikova R., Rektorova I.
CEITEC Research Group: Applied Neuroscience
Research Programme 6: Brain and Mind Research
Summary
Using repetitive transcranial stimulation (rTMS), the authors demonstrated the causal role of the right dorsolateral prefrontal cortex in solving the Tower of London task, i.e. the cognitive task that evaluates spatial-planning, attention, and executive functions.
Antimicrobial Agents and Chemotherapy
Dogs of Nomadic Pastoralists in Northern Kenya Are Reservoirs of Plasmid-Mediated Cephalosporin- and Quinolone-Resistant Escherichia coli, Including Pandemic Clone B2-O25-ST131
Albrechtova, K., Dolejska, M., Cizek, A., Tausova, D. Bebora, L., Literak, I.
CEITEC Research Group:Molecular Bacteriology
Research Programme 7:Molecular Veterinary Medicine
Summary
Resistance in Escherichia coli isolates colonizing gastrointestinal tracts of dogs, cats, and their owners in Northern Kenya was investigated with an emphasis on extended-spectrum beta-lactamases (ESBLs). Totals of 47 (22%, n = 216), 2 (4%, n = 50), and 4 (17%, n = 23) CTX-M-15-producing E. coli isolates were obtained from dogs, cats, and humans, respectively. CTX-M-15-producing E. coli isolates with identical PFGE profiles were detected in animals and humans living in the same area.
