• MeSH
• chromozomy MeSH
• enteroendokrinní buňky MeSH
• hybridní buňky MeSH
• karyotypizace MeSH
• myši MeSH
• techniky in vitro MeSH
• Check Tag
• myši MeSH

• MeSH
• brožury MeSH
• prostituce MeSH
• sexuálně přenosné nemoci MeSH

• Konspekt
• Hygiena. Lidské zdraví
• NLK Obory
• dermatovenerologie

• MeSH
• diabetes mellitus 1. typu genetika   imunologie   MeSH
• genetika MeSH
• HLA antigeny analýza   genetika   klasifikace   MeSH
• rodina MeSH
• Publikační typ
• srovnávací studie MeSH

• MeSH
• Arthrodermataceae ultrastruktura   MeSH
• mikrobiální genetika analýza   MeSH
• růst analýza   MeSH

The onset of an early development is, in mammals, characterized by profound changes of multiple aspects of cellular morphology and behavior. These are including, but not limited to, fertilization and the merging of parental genomes with a subsequent transition from the meiotic into the mitotic cycle, followed by global changes of chromatin epigenetic modifications, a gradual decrease in cell size and the initiation of gene expression from the newly formed embryonic genome. Some of these important, and sometimes also dramatic, changes are executed within the period during which the gene transcription is globally silenced or not progressed, and the regulation of most cellular activities, including those mentioned above, relies on controlled translation. It is known that the blastomeres within an early embryo are prone to chromosome segregation errors, which might, when affecting a significant proportion of a cell within the embryo, compromise its further development. In this review, we discuss how the absence of transcription affects the transition from the oocyte to the embryo and what impact global transcriptional silencing might have on the basic cell cycle and chromosome segregation controlling mechanisms.

• MeSH
• buněčný cyklus genetika   MeSH
• chromatin genetika   MeSH
• embryo savčí fyziologie   MeSH
• embryonální vývoj genetika   MeSH
• genetická transkripce genetika   MeSH
• lidé MeSH
• segregace chromozomů genetika   MeSH
• umlčování genů fyziologie   MeSH
• vývojová regulace genové exprese genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

• MeSH
• Aspergillus MeSH
• mikrobiální genetika MeSH

In several species, including Xenopus, mouse and human, two members of cyclin A family were identified. Cyclin A2, which is ubiquitously expressed in dividing cells and plays role in DNA replication, entry into mitosis and spindle assembly, and cyclin A1, whose function is less clear and which is expressed in spermatocytes, leukemia cells and in postmitotic multiciliated cells. Deletion of the gene showed that cyclin A1 is essential for male meiosis, but nonessential for female meiosis. Our results revealed, that the cyclin A1 is not only dispensable in oocytes, we show here that its expression is in fact undesirable in these cells. Our data demonstrate that the APC/C and proteasome in oocytes are unable to target sufficiently cyclin A1 before anaphase, which leads into anaphase arrest and direct inhibition of separase. The cyclin A1-induced cell cycle arrest is oocyte-specific and the presence of cyclin A1 in early embryos has no effect on cell cycle progression or chromosome division. Cyclin A1 is therefore not only an important cell cycle regulator with biased expression in germline, being essential for male and damaging for female meiosis, its persistent expression during anaphase in oocytes shows fundamental differences between APC/C function in oocytes and in early embryos.

• MeSH
• anafáze * MeSH
• cyklin A1 fyziologie   MeSH
• cyklin A2 fyziologie   MeSH
• fluorescenční mikroskopie MeSH
• meióza MeSH
• metafáze MeSH
• mikroinjekce MeSH
• myši MeSH
• oocyty cytologie   MeSH
• proteasomový endopeptidasový komplex fyziologie   MeSH
• segregace chromozomů * MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In direct compression of tablets, it is crucial to maintain content uniformity within acceptable margins, especially in formulations with low drug loading. To assure it, complex and multistep mixing processes are utilized in the industry. In this study, we suggest the use of a simple segregation test to evaluate mixing process performance and mixture segregation to produce tablets having satisfying content uniformity while keeping the process as simple and low cost as possible. Eventually, the formulation propensity to segregation can be evaluated using process analytical technology (PAT) to adjust the mixing process parameters to changing source drug properties. In this study, that approach was examined on a model drug with a broad batch-to-batch variability in particle size and shape. Excipients were chosen so that the resulting blend composition mimicked some marketed formulations. For each drug batch, two formulation blends were prepared through different preparation processes (one simple and one complex) and subsequently subjected to segregation tests. From those, segregation coefficients were obtained to compare segregation tendencies and homogeneity robustness between the drug batches and the blend preparation methods. The inter-particulate interactions were substantially influenced by the drug particle morphology and size and resulted in different segregation behavior. Based on these findings, a simple segregation test proved to be a useful tool for determining the suitability of different batches of the model drug to be used in a certain formulation. Moreover, for a particular batch A, the test revealed a potential for mixing process simplification and therefore process intensification and cost reduction.

• MeSH
• farmaceutická technologie metody   MeSH
• pomocné látky chemická syntéza   MeSH
• prášky, zásypy, pudry MeSH
• příprava léků metody   MeSH
• tablety MeSH
• tlak MeSH
• velikost částic * MeSH
• Publikační typ
• časopisecké články MeSH

Bacillus subtilis, a Gram-positive bacterium commonly found in soil, is an excellent model organism for the study of basic cell processes, such as cell division and cell differentiation, called sporulation. In B. subtilis the essential genetic information is carried on a single circular chromosome, the correct segregation of which is crucial for both vegetative growth and sporulation. The proper completion of life cycle requires each daughter cell to obtain identical genetic information. The consequences of inaccurate chromosome segregation can lead to formation of anucleate cells, cells with two chromosomes, or cells with incomplete chromosomes. Although bacteria miss the classical eukaryotic mitotic apparatus, the chromosome segregation is undeniably an active process tightly connected to other cell processes as DNA replication and compaction. To fully understand the chromosome segregation, it is necessary to study this process in a wider context and to examine the role of different proteins at various cell life cycle stages. The life cycle of B. subtilis is characteristic by its specific cell differentiation process where, two slightly different segregation mechanisms exist, specialized in vegetative growth and in sporulation.

• MeSH
• Bacillus subtilis genetika   izolace a purifikace   MeSH
• chromozomální proteiny, nehistonové genetika   izolace a purifikace   MeSH
• financování organizované využití   MeSH
• grampozitivní sporulující bakterie genetika   izolace a purifikace   růst a vývoj   MeSH
• histony genetika   izolace a purifikace   MeSH
• rac proteiny vázající GTP genetika   izolace a purifikace   MeSH
• segregace chromozomů genetika   MeSH
• translokace genetická genetika   MeSH

The coexistence of ecologically similar species (i.e. species utilizing the same resource) is a major topic in ecology. Communities are assembled either through the biotic interactions of ecologically similar species, e.g. competition, or by the abiotic separation of species along gradients of environmental conditions. Here, we investigated the temporal segregation, succession and seasonality of dung-inhabiting Coleoptera and Diptera that utilize an identical resource in exactly the same way. The data were collected from two temperate pastures, one in the United Kingdom and the second in the Czech Republic. There was no evident temporal separation between ecologically similar coleopterous or dipterous taxa during succession. In contrast, these two orders were almost perfectly separated seasonally in both combined and site-specific datasets. Flies were most abundant in the summer, and beetles were more abundant in the spring and autumn. Ecologically similar beetles and flies also displayed seasonal separation in both combined and site-specific data. Analyses within site-specific data sets revealed such a separation at both the order and species level. Season is therefore the main temporal axis separating ecologically similar species of dung-inhabiting insects in temperate habitats, while succession aggregates species that may have similar environmental tolerances (to e.g. dung moisture). This separation between ecologically similar taxa of beetles and flies may be attributable to either competition-based niche separation or to temperature tolerance-based habitat filtering, since flies have peak activity in warmer months while beetles have peak activity in cooler months.

• MeSH
• brouci klasifikace   MeSH
• Diptera klasifikace   MeSH
• druhová specificita MeSH
• roční období MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH