Telomeres are nucleoprotein complexes protecting chromosome ends in most eukaryotic organisms. In addition to chromosome ends, telomeric-like motifs can be accumulated in centromeric, pericentromeric and intermediate (i.e., between centromeres and telomeres) positions as so-called interstitial telomeric repeats (ITRs). We mapped the distribution of (TTAGGG)n repeats in the karyotypes of 30 species from nine families of turtles using fluorescence in situ hybridization. All examined species showed the expected terminal topology of telomeric motifs at the edges of chromosomes. We detected ITRs in only five species from three families. Combining our and literature data, we inferred seven independent origins of ITRs among turtles. ITRs occurred in turtles in centromeric positions, often in several chromosomal pairs, in a given species. Their distribution does not correspond directly to interchromosomal rearrangements. Our findings support that centromeres and non-recombining parts of sex chromosomes are very dynamic genomic regions, even in turtles, a group generally thought to be slowly evolving. However, in contrast to squamate reptiles (lizards and snakes), where ITRs were found in more than half of the examined species, and birds, the presence of ITRs is generally rare in turtles, which agrees with the expected low rates of chromosomal rearrangements and rather slow karyotype evolution in this group.

• Klíčová slova
• FISH, ITRs, ITSs, evolution, in situ hybridization, interstitial telomeric repeats, interstitial telomeric sequences, karyotype, telomeres, turtles,
• MeSH
• centromera genetika   MeSH
• hadi genetika   MeSH
• hybridizace in situ fluorescenční MeSH
• ještěři genetika   MeSH
• karyotyp MeSH
• pohlavní chromozomy genetika   MeSH
• repetitivní sekvence nukleových kyselin genetika   MeSH
• telomery genetika   MeSH
• želvy genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Epigenetic mechanisms are involved in regulation of crucial cellular processes in eukaryotic organisms. Data on the epigenetic features of plant telomeres and their epigenetic regulation were published mostly for Arabidopsis thaliana, in which the presence of interstitial telomeric repeats (ITRs) may interfere with genuine telomeres in most analyses. Here, we studied the epigenetic landscape and transcription of telomeres and ITRs in Nicotiana tabacum with long telomeres and no detectable ITRs, and in Ballantinia antipoda with large blocks of pericentromeric ITRs and relatively short telomeres. Chromatin of genuine telomeres displayed heterochromatic as well as euchromatic marks, while ITRs were just heterochromatic. Methylated cytosines were present at telomeres and ITRs, but showed a bias with more methylation toward distal telomere positions and different blocks of B. antipoda ITRs methylated to different levels. Telomeric transcripts TERRA (G-rich) and ARRET (C-rich) were identified in both plants and their levels varied among tissues with a maximum in blossoms. Plants with substantially different proportions of internally and terminally located telomeric repeats are instrumental in clarifying the chromatin status of telomeric repeats at distinct chromosome locations.

• Klíčová slova
• Ballantinia antipoda, DNA methylation, Nicotiana tabacum, chromatin, epigenetics, histone modifications, telomere,
• Publikační typ
• časopisecké články MeSH

BACKGROUND AND AIMS: Most crucifer species (Brassicaceae) have small nuclear genomes (mean 1C-value 617 Mb). The species with the largest genomes occur within the monophyletic Hesperis clade (Mandáková et al., Plant Physiology174: 2062-2071; also known as Clade E or Lineage III). Whereas most chromosome numbers in the clade are 6 or 7, monoploid genome sizes vary 16-fold (256-4264 Mb). To get an insight into genome size evolution in the Hesperis clade (~350 species in ~48 genera), we aimed to identify, quantify and localize in situ the repeats from which these genomes are built. We analysed nuclear repeatomes in seven species, covering the phylogenetic and genome size breadth of the clade, by low-pass whole-genome sequencing. METHODS: Genome size was estimated by flow cytometry. Genomic DNA was sequenced on an Illumina sequencer and DNA repeats were identified and quantified using RepeatExplorer; the most abundant repeats were localized on chromosomes by fluorescence in situ hybridization. To evaluate the feasibility of bacterial artificial chromosome (BAC)-based comparative chromosome painting in Hesperis-clade species, BACs of arabidopsis were used as painting probes. KEY RESULTS: Most biennial and perennial species of the Hesperis clade possess unusually large nuclear genomes due to the proliferation of long terminal repeat retrotransposons. The prevalent genome expansion was rarely, but repeatedly, counteracted by purging of transposable elements in ephemeral and annual species. CONCLUSIONS: The most common ancestor of the Hesperis clade has experienced genome upsizing due to transposable element amplification. Further genome size increases, dominating diversification of all Hesperis-clade tribes, contrast with the overall stability of chromosome numbers. In some subclades and species genome downsizing occurred, presumably as an adaptive transition to an annual life cycle. The amplification versus purging of transposable elements and tandem repeats impacted the chromosomal architecture of the Hesperis-clade species.

• Klíčová slova
• Bunias, Hesperis, Matthiola, Brassicaceae, Genome size evolution, Lineage III, chromosome organization, interstitial telomeric repeats (ITRs), repetitive DNA, retrotransposons, tandem repeats,
• MeSH
• Brassicaceae * MeSH
• délka genomu MeSH
• fylogeneze MeSH
• genom rostlinný * MeSH
• hybridizace in situ fluorescenční MeSH
• molekulární evoluce MeSH
• proliferace buněk MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The nature of neural codes is central to neuroscience. Do neurons encode information through relatively slow changes in the firing rates of individual spikes (rate code) or by the precise timing of every spike (temporal code)? Here we compare the loss of information due to correlations for these two possible neural codes. The essence of Shannon's definition of information is to combine information with uncertainty: the higher the uncertainty of a given event, the more information is conveyed by that event. Correlations can reduce uncertainty or the amount of information, but by how much? In this paper we address this question by a direct comparison of the information per symbol conveyed by the words coming from a binary Markov source (temporal code) with the information per symbol coming from the corresponding Bernoulli source (uncorrelated, rate code). In a previous paper we found that a crucial role in the relation between information transmission rates (ITRs) and firing rates is played by a parameter s, which is the sum of transition probabilities from the no-spike state to the spike state and vice versa. We found that in this case too a crucial role is played by the same parameter s. We calculated the maximal and minimal bounds of the quotient of ITRs for these sources. Next, making use of the entropy grouping axiom, we determined the loss of information in a Markov source compared with the information in the corresponding Bernoulli source for a given word length. Our results show that in the case of correlated signals the loss of information is relatively small, and thus temporal codes, which are more energetically efficient, can replace rate codes effectively. These results were confirmed by experiments.

• Klíčová slova
• Shannon information theory, firing rate, information source, information transmission rate, neural coding,
• MeSH
• akční potenciály * MeSH
• informační teorie * MeSH
• Markovovy řetězce * MeSH
• modely neurologické * MeSH
• nejistota * MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

The crystallization of poorly soluble drug molecules with an excipient into new solid phases called cocrystals has gained a considerable popularity in the pharmaceutical field. In this work, the cocrystal approach was explored for a very poorly water soluble antifungal active, itraconazole (ITR), which was, for the first time, successfully converted into this multicomponent solid using an aromatic coformer, terephthalic acid (TER). The new cocrystal was characterized in terms of its solid-state and structural properties, and a panel of pharmaceutical tests including wettability and dissolution were performed. Evidence of the cocrystal formation was obtained from liquid-assisted grinding, but not neat grinding. An efficient method of the ITR-TER cocrystal formation was ball milling. The stoichiometry of the ITR-TER phase was 2:1 and the structure was stabilized by H-bonds. When comparing ITR-TER with other cocrystals, the intrinsic dissolution rates and powder dissolution profiles correlated with the aqueous solubility of the coformers. The rank order of the dissolution rates of the active pharmaceutical ingredient (API) from the cocrystals was ITR-oxalic acid > ITR-succinic acid > ITR-TER. Additionally, the ITR-TER cocrystal was stable in aqueous conditions and did not transform to the parent drug. In summary, this work presents another cocrystal of ITR that might be of use in pharmaceutical formulations.

• Klíčová slova
• cocrystal, crystal structure, dissolution, itraconazole, mechanochemistry, solid-state, terephthalic acid, thermal analysis, wettability,
• Publikační typ
• časopisecké články MeSH

Cryptococcus neoformans is an opportunistic fungal pathogen that can cause life-threatening invasive fungal infections. As its prevalence and drug resistance continue to rise, cryptococcosis requires new treatment options. Tapping into the potential antifungal effects of traditional drugs or combination therapy has become one of the options. This study was the first to examine the interaction of hydroxychloroquine (HCQ) and itraconazole (ITR) on Cryptococcus neoformans in vitro and in vivo. Our results showed that HCQ alone and in combination with ITR exhibited antifungal activity against C. neoformans planktonic cells. When HCQ was combined with ITR, the minimal inhibitory concentration (MIC) value of HCQ decreased to 32 μg/mL, and the MIC value of ITR decreased from 0.25 μg/mL to 0.06-0.25 μg/mL. The time-killing curve showed that the combined application of HCQ and ITR significantly shortened the killing time, dynamically defining the antifungal activity. The minimum biofilm clearance concentration (MBEC) of HCQ was only 32 μg/mL, which was significantly lower than the MIC of HCQ for planktonic cells. When combined with ITR, the MBEC of ITR decreased from 128 μg/mL to 2-1 μg/mL, and the MBEC of HCQ decreased from 32 μg/mL to 4 μg/mL, indicating a synergistic antifungal biofilm effect. In comparison to ITR alone, the combination of HCQ and ITR treatment increased the survival of C. neoformans-infected Galleria mellonella larvae and decreased the fungal burden of infected larvae. Mechanistic investigations revealed that HCQ might damage C. neoformans cell membranes, impact the structure of fungal cells, cause extracellular material leakage, and have a potent affinity for attaching to the C. neoformans genomic DNA. In conclusion, HCQ has potential clinical application in the treatment of cryptococcosis.

• Klíčová slova
• Antifungal activity, Cryptococcus neoformans, Hydroxychloroquine, Itraconazole, Synergism,
• MeSH
• antifungální látky farmakologie   terapeutické užití   MeSH
• Cryptococcus neoformans * MeSH
• hydroxychlorochin farmakologie   terapeutické užití   MeSH
• itrakonazol farmakologie   MeSH
• kryptokokóza * farmakoterapie   mikrobiologie   MeSH
• mikrobiální testy citlivosti MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antifungální látky MeSH
• hydroxychlorochin MeSH
• itrakonazol MeSH

To date, the majority of zeolites have been prepared by the solvothermal route using organic structure directing agents. Two new zeolites with structural codes PCR and OKO were recently prepared from UTL germanosilicate by removal of the double-four ring (D4R) connecting the dense two-dimensional layers [Nature Chem. 2013, 5, 628]. The corresponding experimental protocol, Assembly-Disassembly-Organization-Reassembly (ADOR), is explored in this contribution with an in silico investigation. The structure and properties of hypothetical zeolites that could be obtained from zeolites with IWW, IWV, IWR, ITR, and ITH topologies using the ADOR protocol are reported based on a computational investigation. A total of 20 new structures are presented together with their characteristics.

• Klíčová slova
• density functional calculations, in silico studies, structure, synthesis, zeolites,
• Publikační typ
• časopisecké články MeSH

In this work, we describe laser modification of poly(methyl methacrylate) films doped with Fast Red ITR, followed by dopant exclusion from the bulk polymer. By this procedure, the polymer can be modified under extremely mild conditions. Creation of surface ordered structure was observed already after application of 15 pulses and 12 mJ cm(-2) fluence. Formation of grating begins in the hottest places and tends to form concentric semi-circles around them. The mechanism of surface ordered structure formation is attributed to polymer ablation, which is more pronounced in the place of higher light intensity. The smoothness of the underlying substrate plays a key role in the quality of surface ordered structure. Most regular grating structures were obtained on polymer films deposited on atomically 'flat' Si substrates. After laser patterning, the dopant was removed from the polymer by soaking the film in methanol.

• Klíčová slova
• Grating, Laser, Modification, Polymer, Surface,
• Publikační typ
• časopisecké články MeSH

While the pivotal role of linker histone H1 in shaping nucleosome organization is well established, its functional interplays with chromatin factors along the epigenome are just starting to emerge. Here we show that, in Arabidopsis, as in mammals, H1 occupies Polycomb Repressive Complex 2 (PRC2) target genes where it favors chromatin condensation and H3K27me3 deposition. We further show that, contrasting with its conserved function in PRC2 activation at genes, H1 selectively prevents H3K27me3 accumulation at telomeres and large pericentromeric interstitial telomeric repeat (ITR) domains by restricting DNA accessibility to Telomere Repeat Binding (TRB) proteins, a group of H1-related Myb factors mediating PRC2 cis recruitment. This study provides a mechanistic framework by which H1 avoids the formation of gigantic H3K27me3-rich domains at telomeric sequences and contributes to safeguard nucleus architecture.

• Klíčová slova
• 3D chromosome organization, Arabidopsis, CP: Molecular biology, CP: Plants, H3K27me3, Polycomb, TRB, Telomere Repeat Binding protein, chromatin accessibility, linker histone H1, telomere,
• MeSH
• Arabidopsis * genetika   metabolismus   MeSH
• chromatin MeSH
• histony metabolismus   MeSH
• PRC2 metabolismus   MeSH
• proteiny huseníčku * genetika   metabolismus   MeSH
• proteiny vázající telomery metabolismus   MeSH
• savci metabolismus   MeSH
• telomery genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chromatin MeSH
• histony MeSH
• PRC2 MeSH
• proteiny huseníčku * MeSH
• proteiny vázající telomery MeSH