Acta Universitatis upsaliensis. Comprehensive summaries of Uppsala dissertations from the Faculty of Science and Technology. 253, ISSN 1104-232X
60 s. : il. ; 24 cm
- Conspectus
- Biochemie. Molekulární biologie. Biofyzika
- NML Fields
- biochemie
- biologie
- mikrobiologie, lékařská mikrobiologie
The adhesion of TiO(2) (anatase structure) nanoparticles to kaolinite substrate was investigated using molecular modeling. Universal force field computation, density function theory computation, and a combination of both two approaches were used. This study enabled the adhesion energy for the TiO(2)/kaolinite nanocomposite to be estimated, and revealed the preferred orientation of the TiO(2) nanoparticles on the kaolinite substrate. The results of all three levels of computation were compared in order to show that the accuracy of universal force field computations is sufficient in this context. The role of nanoparticle size and the importance of the nanoparticle-substrate bonding contribution are presented here and discussed. A comparison of the molecular modeling results with scanning electron microscopy observations showed that the results of the modeling were consistent with the experimental data, and that this approach can be used to help characterize nanocomposites of the nanoparticle/phyllosilicate substrate type.
- MeSH
- Kaolin chemistry MeSH
- Crystallography MeSH
- Quantum Theory MeSH
- Molecular Conformation MeSH
- Models, Molecular MeSH
- Nanoparticles chemistry ultrastructure MeSH
- Nanocomposites chemistry ultrastructure MeSH
- Computer Simulation MeSH
- Surface Properties MeSH
- Thermodynamics MeSH
- Titanium chemistry MeSH
- Particle Size MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
12, 202 s.
Posturálna stabilita je predpokladom dobrého výkonu predovšetkým v streleckej časti súťaže v modernom päťboji. Cieľom štúdie bolo popísať úroveň posturálnej stability moderných päťbojárov a posúdiť jej zmeny z hľadiska charakteru postojových úloh. Súbor tvorili moderní päťbojári (ženy n = 5, muži n = 7, vek 18,7±2,6 rokov), ktorí v aktuálnej sezóne patrili do širšieho reprezentačného výberu Českej republiky. Indikátory posturálnej stability (PS) boli posudzované z merania na tlakovej plošine FootScan. PS sme posudzovali v testoch úzky stoj s a bez zrakovej kontroly (USOO a USZO), flamengo stoj na pravej (FP), resp. ľavej nohe (FL) a flamengo stoj na moli - tanovej podložke na pravej (MFP), resp. ľavej nohe (MFL) prostredníctvom parametrov celkovej dráhy CoP (TT w ) a veľkosti výchylok v medio-laterálnom (∆ x ) a ante - roosterionálnom smere (∆ y ). V diagnostike PS sme v porovnaní testu USOO a USZO v parametri (TT w ) zazna - menali štatisticky a vecne významne rozdiely (p < 0,05; d > 0,8). Pri komparácii vý - sledkov testov FP a FL sme nezaznamenali signifikantné rozdiely (p > 0,05). Podobné výsledky sme dosiahli aj v porovnaní indikátorov v testoch MFP a MFL. Pri komparácii PS v stoji FP a MFP, resp. FL a MFL sme dospeli k rovnakým výsledkom, kedy sme zaznamenali štatisticky a vecne významný rozdiel v sledovanom parametri TT w (p < 0,05; d > 0,8), v prípade porovnania FP a MFP aj v parametri ∆ y . U sledovaných probandov je znateľná podmienenosť posturálnej stability od kvality a množstva aferentných informácií z periférie.
Postural stability is a condition of high quality performance, especially in shooting discipline in modern pentathlon. The aim of the study was to describe the level of postural stability of modern pentathletes and to assess its changes in terms of the type of stances. The research group consisted of modern pentathletes (female n = 5, male n = 7, age 18.7±2.6 years), who were members of wider national team of the Czech Republic in that season. Indicators of postural stability (PS) were assessed from measurement on FootScan force plate. PS was measured in narrow stance with and without sight control (USOO and USZO), flamingo stance on the right (FP) and left leg (FL) and flamingo stance on a foam surface on the right (MFP) and left leg (MFL) using parameters of CoP’s total travelled way (TT w ) and body sways in the lateral (∆ x ) and sagittal plane (∆ y ). Comparison of USOO and USZO revealed both statistically and effect size significant differences in TT w parameter (p < 0.05; d > 0.8). w hen comparing results of FP and FL tests we did not find any significant differences (p > 0.05). Similar results were achieved in comparison of indicators in MFP and MFL tests. In comparison of PS in FP and MFP stances, or FL and MFL, respectively, we found similar results when we recorded statistically and effect size significant difference in TT w parameter (p < 0.05; d > 0.8) and in case of FP and MFP in ∆ y parameter, too. In the tested participants, there is obvious determinacy of postural stability by quality and amount of afferent information form peripheral structures.
- Keywords
- stabilita, centrum tlakových sil, aferentní informace, Footscan,
- MeSH
- Adult MeSH
- Humans MeSH
- Posture physiology MeSH
- Postural Balance * physiology MeSH
- Sports physiology MeSH
- Pressure MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Slovakia MeSH
The sliding clamp, PCNA, plays a central role in DNA replication and repair. In the moving replication fork, PCNA is present at the leading strand and at each of the Okazaki fragments that are formed on the lagging strand. PCNA enhances the processivity of the replicative polymerases and provides a landing platform for other proteins and enzymes. The loading of the clamp onto DNA is performed by the Replication Factor C (RFC) complex, whereas its unloading can be carried out by an RFC-like complex containing Elg1. Mutations in ELG1 lead to DNA damage sensitivity and genome instability. To characterize the role of Elg1 in maintaining genomic integrity, we used homology modeling to generate a number of site-specific mutations in ELG1 that exhibit different PCNA unloading capabilities. We show that the sensitivity to DNA damaging agents and hyper-recombination of these alleles correlate with their ability to unload PCNA from the chromatin. Our results indicate that retention of modified and unmodified PCNA on the chromatin causes genomic instability. We also show, using purified proteins, that the Elg1 complex inhibits DNA synthesis by unloading SUMOylated PCNA from the DNA. Additionally, we find that mutations in ELG1 suppress the sensitivity of rad5Δ mutants to DNA damage by allowing trans-lesion synthesis to take place. Taken together, the data indicate that the Elg1-RLC complex plays an important role in the maintenance of genomic stability by unloading PCNA from the chromatin.
- MeSH
- Chromatin metabolism MeSH
- DNA Helicases genetics MeSH
- DNA biosynthesis MeSH
- Methyl Methanesulfonate toxicity MeSH
- Mutation MeSH
- Genomic Instability * MeSH
- DNA Damage * MeSH
- Proliferating Cell Nuclear Antigen metabolism MeSH
- Recombination, Genetic MeSH
- Saccharomyces cerevisiae Proteins chemistry genetics metabolism MeSH
- Structural Homology, Protein MeSH
- Suppression, Genetic MeSH
- Carrier Proteins chemistry genetics metabolism MeSH
- Structure-Activity Relationship MeSH
- Publication type
- Journal Article MeSH
DNA is a fundamentally important molecule for all cellular organisms due to its biological role as the store of hereditary, genetic information. On the one hand, genomic DNA is very stable, both in chemical and biological contexts, and this assists its genetic functions. On the other hand, it is also a dynamic molecule, and constant changes in its structure and sequence drive many biological processes, including adaptation and evolution of organisms. DNA genomes contain significant amounts of repetitive sequences, which have divergent functions in the complex processes that involve DNA, including replication, recombination, repair, and transcription. Through their involvement in these processes, repetitive DNA sequences influence the genetic instability and evolution of DNA molecules and they are located non-randomly in all genomes. Mechanisms that influence such genetic instability have been studied in many organisms, including within human genomes where they are linked to various human diseases. Here, we review our understanding of short, simple DNA repeats across a diverse range of bacteria, comparing the prevalence of repetitive DNA sequences in different genomes. We describe the range of DNA structures that have been observed in such repeats, focusing on their propensity to form local, non-B-DNA structures. Finally, we discuss the biological significance of such unusual DNA structures and relate this to studies where the impacts of DNA metabolism on genetic stability are linked to human diseases. Overall, we show that simple DNA repeats in bacteria serve as excellent and tractable experimental models for biochemical studies of their cellular functions and influences.
- MeSH
- Bacteria genetics MeSH
- DNA genetics ultrastructure MeSH
- Genome, Bacterial genetics MeSH
- Genome, Human genetics MeSH
- Nucleic Acid Conformation MeSH
- Humans MeSH
- Microsatellite Repeats genetics MeSH
- Genomic Instability genetics MeSH
- Repetitive Sequences, Nucleic Acid genetics MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
