• MeSH
• antifungální látky * analýza   biosyntéza   MeSH
• chemické jevy MeSH
• chemie MeSH
• Streptomyces metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antifungální látky * MeSH

Smart self-organising systems attract considerable attention in the scientific community. In order to control and stabilise the liquid crystalline behaviour, and hence the self-organisation, the polymerisation process can be effectively used. Mesogenic units incorporated into the backbones as functional side chains of weakly cross-linked macromolecules can become orientationally ordered. Several new calamitic reactive mesogens possessing the vinyl terminal group with varying flexible chain lengths and with/without lateral substitution by the methyl (methoxy) groups have been designed and studied. Depending on the molecular structure, namely, the type and position of the lateral substituents, the resulting materials form the nematic, the orthogonal SmA and the tilted SmC phases in a reasonably broad temperature range, and the structure of the mesophases was confirmed by X-ray diffraction experiments. The main objective of this work is to contribute to better understanding of the molecular structure-mesomorphic property relationship for new functional reactive mesogens, aiming at further design of smart self-assembling macromolecular materials for novel sensor systems.

• Klíčová slova
• liquid crystal, reactive mesogen, self-assembling behaviour, smectic phases, vinyl group,
• Publikační typ
• časopisecké články MeSH

Blood group B glycosphingolipids (B-GSLs) are substrates of the lysosomal alpha-galactosidase A (AGAL). Similar to its major substrate-globotriaosylceramide (Gb3Cer)-B-GSLs are not degraded and accumulate in the cells of patients affected by an inherited defect of AGAL activity (Fabry disease-FD).The pancreas is a secretory organ known to have high biosynthesis of blood group GSLs. Herein, we provide a comprehensive overview of the biochemical and structural abnormalities in pancreatic tissue from two male FD patients with blood group B. In both patients, we found major accumulation of a variety of complex B-GSLs carrying predominantly hexa- and hepta-saccharide structures. The subcellular pathology was dominated by deposits containing B-glycoconjugates and autofluorescent ceroid. The contribution of Gb3Cer to the storage was minor. This abnormal storage pattern was specific for the pancreatic acinar epithelial cells. Other pancreatic cell types including those of islets of Langerhans were affected much less or not at all.Altogether, we provide evidence for a key role of B-antigens in the biochemical and morphological pathology of the exocrine pancreas in FD patients with blood group B. We believe that our findings will trigger further studies aimed at assessing the potential pancreatic dysfunction in this disease.

• MeSH
• ABO systém krevních skupin metabolismus   MeSH
• acinární buňky metabolismus   ultrastruktura   MeSH
• beta-buňky metabolismus   ultrastruktura   MeSH
• Fabryho nemoc krev   metabolismus   patologie   MeSH
• galaktosa analýza   metabolismus   MeSH
• glykosfingolipidy chemie   metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• pankreas metabolismus   ultrastruktura   MeSH
• studie případů a kontrol MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ABO systém krevních skupin MeSH
• galaktosa MeSH
• glykosfingolipidy MeSH

N-terminal acetyltransferases (NATs) belong to the superfamily of acetyltransferases. They are enzymes catalysing the transfer of an acetyl group from acetyl coenzyme A to the N-terminus of polypeptide chains. N-terminal acetylation is one of the most common protein modifications. To date, not much is known on the molecular basis for the exclusive substrate specificity of NATs. All NATs share a common fold called GNAT. A characteristic of NATs is the β6β7 hairpin loop covering the active site and forming with the α1α2 loop a narrow tunnel surrounding the catalytic site in which cofactor and polypeptide meet and exchange an acetyl group. We investigated the dynamics-function relationships of all available structures of NATs covering the three domains of Life. Using an elastic network model and normal mode analysis, we found a common dynamics pattern conserved through the GNAT fold; a rigid V-shaped groove formed by the β4 and β5 strands and splitting the fold in two dynamical subdomains. Loops α1α2, β3β4 and β6β7 all show clear displacements in the low frequency normal modes. We characterized the mobility of the loops and show that even limited conformational changes of the loops along the low-frequency modes are able to significantly change the size and shape of the ligand binding sites. Based on the fact that these movements are present in most low-frequency modes, and common to all NATs, we suggest that the α1α2 and β6β7 loops may regulate ligand uptake and the release of the acetylated polypeptide.

• Klíčová slova
• Acetylation, Ligand specificity, N-terminal acetyltransferases, Normal modes analysis, Protein dynamics,
• Publikační typ
• časopisecké články MeSH

Retrotransposons are ubiquitous in the plant genomes and are responsible for their plasticity. Recently, we described a novel family of gypsy-like retrotransposons, named Retand, in the dioecious plant Silene latifolia possessing evolutionary young sex chromosomes of the mammalian type (XY). Here we have analyzed long terminal repeats (LTRs) of Retand that were amplified from laser microdissected X and Y sex chromosomes and autosomes of S. latifolia. A majority of X and Y-derived LTRs formed a few separate clades in phylogenetic analysis reflecting their high intrachromosomal similarity. Moreover, the LTRs localized on the Y chromosome were less divergent than the X chromosome-derived or autosomal LTRs. These data can be explained by a homogenization process, such as gene conversion, working more intensively on the Y chromosome.

• MeSH
• chromozomy rostlin genetika   MeSH
• DNA primery genetika   MeSH
• DNA rostlinná genetika   MeSH
• fylogeneze MeSH
• genová konverze MeSH
• hybridizace in situ fluorescenční MeSH
• koncové repetice * MeSH
• modely genetické MeSH
• molekulární evoluce MeSH
• retroelementy * MeSH
• sekvence nukleotidů MeSH
• Silene genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA primery MeSH
• DNA rostlinná MeSH
• retroelementy * MeSH

Stratified and precision nutrition refers to disease management or prevention of disease onset, based on dietary interventions tailored to a person's characteristics, biology, gut microbiome, and environmental exposures. Such treatment models may lead to more effective management of inflammatory bowel disease (IBD) and reduce risk of disease development. This societal position paper aimed to report advances made in stratified and precision nutritional therapy in IBD. Following a structured literature search, limited to human studies, we identified four relevant themes: (a) nutritional epidemiology for risk prediction of IBD development, (b) food-based dietary interventions in IBD, (c) exclusive enteral nutrition (EEN) for Crohn's disease (CD) management, and (d) pre- and probiotics for IBD management. There is scarce literature upon which we can make recommendations for precision or stratified dietary therapy for IBD, both for risk of disease development and disease management. Certain single-nucleotide polymorphisms related to polyunsaturated fatty acid (PUFA) metabolism may modify the effect dietary PUFA have in increasing the risk of IBD development. Non-colonic CD, mild-to-moderate CD, and high microbiota richness may predict success of EEN and may be used both for prediction of treatment continuation, but also for early cessation in nonresponders. There is currently insufficient evidence to make recommendations for precision or stratified dietary therapy for patients with established IBD. Despite the great interest in stratified and precision nutrition, we currently lack data to support conclusive recommendations. Replication of early findings by independent research groups and within structured clinical interventions is required.

• Klíčová slova
• exclusive enteral nutrition (EEN), inflammatory bowel disease (IBD), precision nutrition, prediction, stratified nutrition,
• MeSH
• Crohnova nemoc * terapie   MeSH
• dítě MeSH
• idiopatické střevní záněty * terapie   MeSH
• indukce remise MeSH
• lidé MeSH
• pomocný zdravotnický personál MeSH
• translační biomedicínský výzkum MeSH
• veřejné mínění MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

In contrast to the reaction of vinyl(alkynyl)silanes with 9-BBN-H, leading to the quantitative formation of 5-R-4-(9-BBN)-2,3-dihydro-1H-siloles, treatment of bis(alkynyl)silanes bearing one terminal alkynyl group with 2 equiv of 9-BBN-H followed by methanolysis afforded 5-R-4-(9-BBN)-2,5-dihydro-1H-siloles with yields of 85-90% (by NMR integration). The reaction proceeds via a double 1,2-hydroboration of the terminal triple bond with the formation of the geminal diborane followed by ring closure via intramolecular 1,1-carboboration of the remaining alkynyl fragment. Depending on the nature of the substituent R in position 5, the allylic BBN group locates in position 3 (R = Ph) or position 5 (R = SiHMe2, SiMe3) to give 2,3- or 2,5-dihydrosiloles, respectively. The protodeborylation of the allylic BBN group with MeOH of both 3,4-(9-BBN)2-2,3-dihydro- and 4,5-(9-BBN)2-2,5-dihydrosiloles results in the exclusive formation of 4-(9-BBN)-2,5-dihydrosiloles. In all cases, the formation of 10-12% of 2-R-2,4-(9-BBN)2-2,3-dihydrosilole minor isomers has been observed, which occurs from vicinal diboranes formed as side products by a second hydroboration of the terminal triple bond. Similarly, treatment of the tri- and tetraalkynes containing a terminal triple bond with 2 equiv of 9-BBN-H followed by treatment with methanol resulted in the high-yield formation of 1,2,6,6a-tetrahydro-1,6-disilapentalenes and 2,6,7,7a-tetrahydro-1,6,7-trisila-1H-cyclopenta[a]pentalenes, respectively.

• Publikační typ
• časopisecké články MeSH

Retrotransposons are "copy-and-paste" insertional mutagens that substantially contribute to mammalian genome content. Retrotransposons often carry long terminal repeats (LTRs) for retrovirus-like reverse transcription and integration into the genome. We report an extraordinary impact of a group of LTRs from the mammalian endogenous retrovirus-related ERVL retrotransposon class on gene expression in the germline and beyond. In mouse, we identified more than 800 LTRs from ORR1, MT, MT2, and MLT families, which resemble mobile gene-remodeling platforms that supply promoters and first exons. The LTR-mediated gene remodeling also extends to hamster, human, and bovine oocytes. The LTRs function in a stage-specific manner during the oocyte-to-embryo transition by activating transcription, altering protein-coding sequences, producing noncoding RNAs, and even supporting evolution of new protein-coding genes. These functions result, for example, in recycling processed pseudogenes into mRNAs or lncRNAs with regulatory roles. The functional potential of the studied LTRs is even higher, because we show that dormant LTR promoter activity can rescue loss of an essential upstream promoter. We also report a novel protein-coding gene evolution-D6Ertd527e-in which an MT LTR provided a promoter and the 5' exon with a functional start codon while the bulk of the protein-coding sequence evolved through a CAG repeat expansion. Altogether, ERVL LTRs provide molecular mechanisms for stochastically scanning, rewiring, and recycling genetic information on an extraordinary scale. ERVL LTRs thus offer means for a comprehensive survey of the genome's expression potential, tightly intertwining with gene expression and evolution in the germline.

• MeSH
• endogenní retroviry MeSH
• genetická transkripce MeSH
• koncové repetice * MeSH
• křečci praví MeSH
• lidé MeSH
• molekulární evoluce * MeSH
• myši MeSH
• oocyty cytologie   metabolismus   MeSH
• promotorové oblasti (genetika) MeSH
• regulace genové exprese * MeSH
• retroelementy * MeSH
• skot MeSH
• zvířata MeSH
• zygota cytologie   metabolismus   MeSH
• Check Tag
• křečci praví MeSH
• lidé MeSH
• myši MeSH
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• retroelementy * MeSH

• MeSH
• acetáty metabolismus   MeSH
• alanin metabolismus   MeSH
• glutamáty metabolismus   MeSH
• glutaráty metabolismus   MeSH
• hydrogenuhličitany metabolismus   MeSH
• kolorimetrie MeSH
• malonáty metabolismus   MeSH
• propionáty metabolismus   MeSH
• pyruváty metabolismus   MeSH
• radioizotopy uhlíku MeSH
• Streptomyces aureofaciens metabolismus   MeSH
• sukcináty metabolismus   MeSH
• tetracyklin biosyntéza   MeSH
• uracil metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetáty MeSH
• alanin MeSH
• glutamáty MeSH
• glutaráty MeSH
• hydrogenuhličitany MeSH
• malonáty MeSH
• propionáty MeSH
• pyruváty MeSH
• radioizotopy uhlíku MeSH
• sukcináty MeSH
• tetracyklin MeSH
• uracil MeSH

Ogre elements are a group of LTR retrotransposons recently discovered in legume plants, where they constitute almost 40% of the genome in some species. They are exceptional in their size (reaching 25 kb) and possess several specific features, including an intron within a polyprotein-coding region, and an extra open reading frame (ORF1) encoding a protein of unknown function located upstream of the gag gene. Although these features make Ogres interesting for further research, identification of additional elements from a broader range of plant taxa has been complicated by the divergence of their sequences, preventing their detection using similarity-based searches. Here we report the results of structure-based computational searches for Ogre elements in available plant genomic sequences, which proved to be more efficient and revealed occurrences of Ogres in three families of dicot plants (Leguminosae, Solanaceae and Salicaceae). In addition, a representative set of 85 elements was retrieved from a model legume species Medicago truncatula. All identified full-length elements were used for comparative analysis, which showed that in spite of only little conservation of their nucleotide sequences, their protein domains were highly conserved, including several regions within ORF1. Further, the elements shared the same functional regions, including a primer binding site complementary to tRNA(arg), a conserved motif within a polypurine tract, and a putative intron between the pro and rt/rh coding domains. These findings, together with analysis of their phylogenetic relationship to other retrotransposons based on similarities of rt domains suggest that Ogre elements from different plant taxa have a common origin and thus constitute a distinct group of Ty3/gypsy retrotransposons.

• MeSH
• DNA rostlinná genetika   MeSH
• fylogeneze MeSH
• introny MeSH
• koncové repetice MeSH
• otevřené čtecí rámce MeSH
• retroelementy * MeSH
• rostliny klasifikace   genetika   MeSH
• sekvence nukleotidů MeSH
• sekvenční homologie nukleových kyselin MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA rostlinná MeSH
• retroelementy * MeSH