The current work is focused on numerical and experimental studies of woven fabric composites modified by hybridisation with biological (cellulosic) filler materials. The mechanical performance of the composites is characterized under tensile, bending and impact loads and the effect of hybridisation is observed with respect to pure and nonhybrid composites. Numerical models are developed using computational tools to predict mechanical performance under tensile loading. The computational prediction results are compared and validated with relevant experimental results. This research is aimed at understanding the mechanical performance of basalt-epoxy composites partially reinforced with micro-/nano-sized bio-fillers from cellulose and intended for various application areas. Different weave structures, e.g., plain, twill, matt, etc., were investigated with respect to the mechanical properties of the hybrid composites. The effects of hybridizing with cellulose particles and different weave patterns of the basalt fabric are studied. In general, the use of high-strength fibres such as basalt along with cellulosic fillers representing up to 3% of the total weight improves the mechanical performance of the hybrid structures. The thermomechanical performance of the hybrid composites improved significantly by using basalt fabric as well as by addition of 3% weight of cellulosic fillers. Results reveal the advantages of hybridisation and the inclusion of natural cellulosic fillers in the hybrid composite structures. The material developed is suitable for high-end applications in components for construction that demand advanced mechanical and thermomechanical performance. Furthermore, the inclusion of biodegradable fillers fulfills the objectives of sustainable and ecological construction materials.

• Klíčová slova
• basalt woven fabrics, cellulosic/bio-fillers, hybrid composites, mechanical properties, modulus,
• Publikační typ
• časopisecké články MeSH

Hybrid sterility is a reproductive isolation barrier between diverging taxa securing the early steps of speciation. Hybrid sterility is ubiquitous in the animal and plant kingdoms, but its genetic control is poorly understood. In our previous studies, we have uncovered the sterility of hybrids between musculus and domesticus subspecies of the house mouse, which is controlled by the Prdm9 gene, the X-linked Hstx2 locus, and subspecific heterozygosity for genetic background. To further investigate this form of genic-driven chromosomal sterility, we constructed a simplified hybrid sterility model within the genome of the domesticus subspecies by swapping domesticus autosomes with their homologous partners from the musculus subspecies. We show that the "sterility" allelic combination of Prdm9 and Hstx2 can be activated by a musculus/domesticus heterozygosity of as few as two autosomes, Chromosome 17 (Chr 17) and Chr 18 and is further enhanced when another heterosubspecific autosomal pair is present, whereas it has no effect on meiotic progression in the pure domesticus genome. In addition, we identify a new X-linked hybrid sterility locus, Hstx3, at the centromeric end of Chr X, which modulates the incompatibility between Prdm9 and Hstx2. These results further support our concept of chromosomal hybrid sterility based on evolutionarily accumulated divergence between homologous sequences. Based on these and previous results, we believe that future studies should include more information on the mutual recognition of homologous chromosomes at or before the first meiotic prophase in interspecific hybrids, as this may serve as a general reproductive isolation checkpoint in mice and other species.

• Klíčová slova
• Mus musculus, chromosome, genomes, hybrid, meiosis, speciation,
• MeSH
• genom MeSH
• histonlysin-N-methyltransferasa * genetika   MeSH
• hybridizace genetická * MeSH
• infertilita genetika   MeSH
• myši MeSH
• reprodukční izolace MeSH
• vznik druhů (genetika) MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• histonlysin-N-methyltransferasa * MeSH
• prdm9 protein, mouse MeSH Prohlížeč

Hybrid sterility is one of the reproductive isolation mechanisms leading to speciation. Prdm9, the only known vertebrate hybrid-sterility gene, causes failure of meiotic chromosome synapsis and infertility in male hybrids that are the offspring of two mouse subspecies. Within species, Prdm9 determines the sites of programmed DNA double-strand breaks (DSBs) and meiotic recombination hotspots. To investigate the relation between Prdm9-controlled meiotic arrest and asynapsis, we inserted random stretches of consubspecific homology on several autosomal pairs in sterile hybrids, and analyzed their ability to form synaptonemal complexes and to rescue male fertility. Twenty-seven or more megabases of consubspecific (belonging to the same subspecies) homology fully restored synapsis in a given autosomal pair, and we predicted that two or more DSBs within symmetric hotspots per chromosome are necessary for successful meiosis. We hypothesize that impaired recombination between evolutionarily diverged chromosomes could function as one of the mechanisms of hybrid sterility occurring in various sexually reproducing species.

• Klíčová slova
• Prdm9, chromosomes, evolutionary biology, gene expression, genomics, homology-dependent meiotic chromosome pairing, mouse, speciation, synaptonemal complex,
• MeSH
• biologická evoluce * MeSH
• chiméra genetika   MeSH
• chromozomy genetika   MeSH
• dvouřetězcové zlomy DNA MeSH
• histonlysin-N-methyltransferasa genetika   MeSH
• hybridizace genetická MeSH
• infertilita genetika   MeSH
• meióza genetika   MeSH
• mužská infertilita genetika   MeSH
• myši MeSH
• párování chromozomů genetika   MeSH
• rekombinace genetická MeSH
• reprodukční izolace MeSH
• synaptonemální komplex genetika   MeSH
• vznik druhů (genetika) MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• histonlysin-N-methyltransferasa MeSH
• prdm9 protein, mouse MeSH Prohlížeč

Yeast two-hybrid system was modified to allow easy detection of prokaryotic protein-protein interactions. Three plasmids (pGBR1, pGBR2, pGBR3) with the ClaI restriction site shifted in the three possible reading frames in fusion with GAL4 activating domain were constructed. The modified plasmids were used for identification of protein partners of FtsZ from Bacillus subtilis. Among partners of FtsZ the FtsA protein and a globular part of the SpoIIE protein were identified. The protein interactions were quantified by measurements of beta-galactosidase activity in yeast cells using 4-methylumbelliferyl beta-D-galactopyranoside as fluorogenic substrate.

• MeSH
• Bacillus subtilis genetika   metabolismus   MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• beta-galaktosidasa metabolismus   MeSH
• cytoskeletální proteiny * MeSH
• genomová knihovna MeSH
• plazmidy genetika   MeSH
• techniky dvojhybridového systému * MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální proteiny MeSH
• beta-galaktosidasa MeSH
• cytoskeletální proteiny * MeSH
• FtsZ protein, Bacteria MeSH Prohlížeč

Analysis of protein-protein interactions (PPI) is key for the understanding of most protein assemblies including structural maintenance of chromosomes (SMC) complexes. SMC complexes are composed of SMC proteins, kleisin, and kleisin-interacting subunits. These subunits interact in specific ways to constitute and regulate the closed structure of the complexes. Specifically, kleisin molecules bridge the SMC dimers and the kleisin-interacting subunits modulate stability of the bridge. Here we describe a multicomponent version of a yeast two-hybrid (Y2H) method and its application for analysis of the bridging role of the Nse4 kleisin in the SMC5/6 complex. Using this technique, we also show a stabilizing effect of KITE (kleisin-interacting tandem winged-helix element) proteins on SMC5/6.

• Klíčová slova
• KITE proteins, Kleisin bridge, Multicomponent yeast two-hybrid (Y2H) system, Non-SMC Element (Nse) subunits, Protein–protein interactions, SMC5/6, Structural maintenance of chromosomes (SMC) complexes,
• MeSH
• chromozomy hub fyziologie   MeSH
• mapy interakcí proteinů fyziologie   MeSH
• multiproteinové komplexy metabolismus   MeSH
• podjednotky proteinů metabolismus   MeSH
• proteiny buněčného cyklu metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny metabolismus   MeSH
• Saccharomyces cerevisiae metabolismus   MeSH
• techniky dvojhybridového systému MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• multiproteinové komplexy MeSH
• podjednotky proteinů MeSH
• proteiny buněčného cyklu MeSH
• Saccharomyces cerevisiae - proteiny MeSH

The Dobzhansky-Muller model of incompatibilities explains reproductive isolation between species by incorrect epistatic interactions. Although the mechanisms of speciation are of great interest, no incompatibility has been characterized at the gene level in mammals. The Hybrid sterility 1 gene (Hst1) participates in the arrest of meiosis in F(1) males of certain strains from two Mus musculus subspecies, e.g., PWD from M. m. musculus and C57BL/6J (henceforth B6) from M. m. domesticus. Hst1 has been identified as a meiotic PR-domain gene (Prdm9) encoding histone 3 methyltransferase in the male offspring of PWD females and B6 males, (PWD×B6)F(1). To characterize the incompatibilities underlying hybrid sterility, we phenotyped reproductive and meiotic markers in males with altered copy numbers of Prdm9. A partial rescue of fertility was observed upon removal of the B6 allele of Prdm9 from the azoospermic (PWD×B6)F(1) hybrids, whereas removing one of the two Prdm9 copies in PWD or B6 background had no effect on male reproduction. Incompatibility(ies) not involving Prdm9(B6) also acts in the (PWD×B6)F(1) hybrids, since the correction of hybrid sterility by Prdm9(B6) deletion was not complete. Additions and subtractions of Prdm9 copies, as well as allelic replacements, improved meiotic progression and fecundity also in the progeny-producing reciprocal (B6×PWD)F(1) males. Moreover, an increased dosage of Prdm9 and reciprocal cross enhanced fertility of other sperm-carrying male hybrids, (PWD×B6-C3H.Prdm9)F(1), harboring another Prdm9 allele of M. m. domesticus origin. The levels of Prdm9 mRNA isoforms were similar in the prepubertal testes of all types of F(1) hybrids of PWD with B6 and B6-C3H.Prdm9 despite their different prospective fertility, but decreased to 53% after removal of Prdm9(B6). Therefore, the Prdm9(B6) allele probably takes part in posttranscriptional dominant-negative hybrid interaction(s) absent in the parental strains.

• MeSH
• alely MeSH
• chiméra * genetika   fyziologie   MeSH
• fertilita genetika   MeSH
• genetická epistáze * MeSH
• histonlysin-N-methyltransferasa genetika   MeSH
• hybridizace genetická MeSH
• mapování chromozomů MeSH
• meióza MeSH
• mužská infertilita genetika   MeSH
• myši MeSH
• reprodukční izolace MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• histonlysin-N-methyltransferasa MeSH
• prdm9 protein, mouse MeSH Prohlížeč

Parasite hybrid zones resulting from host secondary contact have never been described in nature although parasite hybridization is well known and secondary contact should affect them similarly to free-living organisms. When host populations are isolated, diverge and recontact, intimate parasites (host specific, direct life cycle) carried during isolation will also meet and so may form parasite hybrid zones. If so, we hypothesize these should be narrower than the host's hybrid zone as shorter parasite generation time allows potentially higher divergence. We investigate multilocus genetics of two parasites across the European house mouse hybrid zone. We find each host taxon harbours its own parasite taxa. These also hybridize: Parasite hybrid zones are significantly narrower than the host's. Here, we show a host hybrid zone is a suture zone for a subset of its parasite community and highlight the potential of such systems as windows on the evolutionary processes of host-parasite interactions and recombinant pathogen emergence.

• Klíčová slova
• Mus musculus, Pneumocystis murina, Syphacia obvelata, hybrid parasites, secondary contact hybrid zones, suture zone,
• MeSH
• fylogeneze MeSH
• genetické markery MeSH
• genotyp MeSH
• hlístice genetika   MeSH
• hybridizace genetická * MeSH
• mitochondriální DNA genetika   MeSH
• myši genetika   parazitologie   MeSH
• paraziti genetika   MeSH
• Pneumocystis genetika   MeSH
• populační genetika * MeSH
• zvířata MeSH
• Check Tag
• myši genetika   parazitologie   MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Německo MeSH
• Názvy látek
• genetické markery MeSH
• mitochondriální DNA MeSH

The karyotype of HY 5/3--4 hybrid cells formed by fusion of diploid and heteroploid murine cells (LS/BLxR-AG/20) consisted of 60--75 chromosomes (modal number 72). The G-banding technique made it possible to identify the origin of the chromosomes; it is concluded that due to chromosomal segregation the hybrid genome lost preferentially the chromosomes derived from the diploid parental line LS/BL. Even after long-term culture in vitro, the chromosomal complement of hybrid cells retained all bi-armed chromosomes and most of the telocentrics, derived from the heteroploid parental cells.

• MeSH
• buněčné linie MeSH
• chromozomy * MeSH
• diploidie MeSH
• hybridní buňky MeSH
• karyotypizace MeSH
• lidé MeSH
• myši MeSH
• ploidie MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Hybrid advantage, described as the superiority of hybrids in some traits over their parents and termed the "heterosis effect," is widely documented in the case of reciprocal crosses of parental species (i.e., hybrids representing the F1 generation). In fish, high survival, fast growth and better health status have been widely documented in F1 hybrids. Nonetheless, the effects of interspecific hybridization on vigour, physiology and immunity-related traits in fish are largely unknown, especially concerning native systems of coexisting parental and hybrid genomes in the same habitat. The present study examined the potential physiological and immune aspects of hybrid heterosis by comparing condition status (measured especially by indexes), haematological profile, glucose concentration and selected parameters of non-specific and specific immunity between the evolutionarily divergent non-congeneric cyprinoid species Abramis brama and Rutilus rutilus and their hybrids representing the F1 generation, all of them caught in nature. Clear differences were documented for vigour-related, physiological and immune parameters between the two divergent species. Hybrids generally tended to express intermediate characters of the measured traits, likely generated by the evolutionary divergence of the hybridizing species; nonetheless, for some traits, hybrids exhibited a character that was more similar to one parental species than to the other. This was interpreted as the heterozygote advantage for F1 hybrids. It is suggested that a maternally inherited genetic background may potentially influence the expression of some branches of non-specific immunity or other aspects related to the fish health status.

• Klíčová slova
• cyprinoid fish, heterosis effect, hybridization, immunity, vigour,
• MeSH
• biologická evoluce * MeSH
• Cyprinidae genetika   MeSH
• fenotyp MeSH
• heterozygot MeSH
• hybridizace genetická * MeSH
• hybridní efekt * MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Micro/nano biomimetic systems that convert energy from the surroundings into mechanical motion have emerged as promising tools to enhance the efficiencies of different biomedical and environmental processes. The inclusion of multiple engines into the same device has become a promising strategy to achieve dual/triple stimuli responses. Such hybrid micro/nanoswimmers combining different propulsion forces exhibit advanced motion behaviors and different physical features that are interesting not only to achieve strong propulsion capabilities in complex environments but also to modulate their movement according to the intended use. The development of hybrid systems that can be actuated by both light and biocompatible fuels is of particular interest. This minireview covers the main types of photoactive/biocatalytic micro/nanoswimmers developed so far. Their main photoresponsive and enzymatic components are discussed along with the most representative designs. The applicability of such hybrid machines for analyte sensing, antibacterial and therapeutical uses is also described. The remaining challenges and opportunities are then explored.

• Klíčová slova
• Enzymes, Hybrid systems, Micro/nanoswimmers, Photobiocatalysis, Photocatalysis,
• MeSH
• biokatalýza * MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH