https://hdl.handle.net/20.500.14178/908 2026-04-21T10:42:14Z 2026-04-21T10:42:14Z Bruštíková, Kateřina Forstová, Jitka Holajová, Barbora Huerfano Meneses, Sandra https://hdl.handle.net/20.500.14178/3736 2026-04-14T01:00:16Z 2026-01-01T00:00:00Z

Remodeling of the cellular membrane architecture in response to BK polyomavirus infection Bruštíková, Kateřina; Forstová, Jitka; Holajová, Barbora; Huerfano Meneses, Sandra BK polyomavirus (BKPyV) is a human pathogen that causes severe disease in immunocompromised individuals. Although discovered in the 1970s, important gaps in our understanding of BKPyV biology persist. Key unresolved areas include the precise molecular mechanisms governing viral latency and reactivation, the specific host and viral factors determining the virus tropism towards the urinary track, and the intricate virus-host interactions that drive clinical pathogenesis. These unresolved biological questions have stalled the development of targeted therapeutics; as a result, no specific antiviral therapy is currently available for BKPyV-related diseases. In this review, we examined findings from both experimental models and clinical samples that investigate how BKPyV remodels host organelles and the molecular pathways underlying these alterations. We focus on BKPyV-driven changes in cellular membranes, including endoplasmic reticulum remodeling, mitochondrial disruption, the formation of endoplasmic reticulum-derived tubuloreticular structures, vacuoles, and autophagosomes, as well as the accumulation of lipid droplets. Collectively, these organelle-specific modifications highlight membrane remodeling as a central feature of BKPyV replication and pathogenesis. Addressing the key knowledge gaps in the molecular basis of virus-induced membrane remodeling will be critical for guiding the development of effective antiviral strategies.

2026-01-01T00:00:00Z Březina, Jiří Brabec, Tomáš Machač, David Vobořil, Matouš Ballek, Ondřej Pačes, Jan Sýkora, Vojtěch Jančovičová, Kristína Valter, Evgeny Kováčová, Katarína Manning, Jasper Tahtahová, Valerie Čepková, Adéla Dobešová, Martina Dobeš, Jan Kubovčiak, Jan Kolář, Michal Kašpárek, Petr Sedlacek, Radislav Štepánek, Ondřej Černý, Jan Tsukita, Sachiko Malissen, Bernard Anderson, Graham Filipp, Dominik https://hdl.handle.net/20.500.14178/3734 2026-04-14T01:00:09Z 2026-01-01T00:00:00Z

Claudin 1 – mediated positioning of DC1 to mTECs is essential for maintenance of central tolerance Březina, Jiří; Brabec, Tomáš; Machač, David; Vobořil, Matouš; Ballek, Ondřej; Pačes, Jan; Sýkora, Vojtěch; Jančovičová, Kristína; Valter, Evgeny; Kováčová, Katarína; Manning, Jasper; Tahtahová, Valerie; Čepková, Adéla; Dobešová, Martina; Dobeš, Jan; Kubovčiak, Jan; Kolář, Michal; Kašpárek, Petr; Sedlacek, Radislav; Štepánek, Ondřej; Černý, Jan; Tsukita, Sachiko; Malissen, Bernard; Anderson, Graham; Filipp, Dominik Central tolerance, which relies on the presentation of self-antigens by mTECs and DCs, prevents autoimmunity by eliminating self-reactive T cells. While mTECs produce self-antigens autonomously, DCs acquire them from mTECs via cooperative antigen transfer (CAT). We previously showed that mTEC and DC subsets exhibit preferential pairing in CAT, providing a rationale for the existence of molecular determinants underpinning this pairing and its outcome. Here, we compared the transcriptomes of CAT-experienced and CAT-inexperienced DCs and identified Claudin 1 as a molecule involved in CAT and type 1 DC (DC1) maturation. DC1-specific ablation of Claudin 1 resulted in decreased CAT to late mature DC1s and dramatically diminished DC1 maturation. These phenotypes correlated with the displacement of DC1s from mTECs and their decreased expression of MHCII pathway genes. This translated into impaired Treg selection and clonal deletion, ultimately manifesting in symptoms of multiorgan autoimmunity and shortened lifespan. Collectively, our results identify thymic DC1-derived Claudin 1 as a regulator of immune tolerance.

2026-01-01T00:00:00Z Martinovská, Aneta Mudrák, Ondřej Frouz, Jan https://hdl.handle.net/20.500.14178/3732 2026-04-09T01:00:18Z 2025-01-01T00:00:00Z

Effects of Bioturbation by Earthworms on Litter Flammability in Young and Mature Afforested Stands Martinovská, Aneta; Mudrák, Ondřej; Frouz, Jan The quantity, quality, and accumulation rate of plant litter play a key role in forest floor flammability and, by extension, fire regimes. The varying foliage properties of different tree species also determine litter's decomposition and its accumulation on the forest floor. The removal of litter by soil fauna, i.e., bioturbation, depends on both the dominant tree species and the successional stage of the forest stand. This research involved laboratory mesocosm experiments aiming to determine the effects of litter quality and earthworm activity on the flammability of the forest floor material at different successional ages. The mesocosms simulated the planting of four tree species (the broadleaf species Alnus glutinosa (L.) Gaertn. (Black alder) and Quercus robur L. (English oak) and the conifers Picea omorika (Pan & ccaron;i & cacute;) Purk. (Serbian spruce) and Pinus nigra J.F. Arnold (Austrian pine)) at a reclamation site near Sokolov (NW Czechia). The mesocosms contained litter from these different tree species, placed directly on overburden soil (immature soil) or on well-developed Oe and A layers (mature soil), inoculated or not inoculated with earthworms, and incubated for 4 months. The surface material in the mesocosms was then subjected to simulated burn events, and the fire path and soil temperature changes were recorded. Burn testing showed that litter type (tree species) and soil maturity significantly influenced flammability. Pine had longer burning times and burning paths and higher post-burn temperatures than those of the other tree species. The immature soil with earthworms had significantly shorter burning times, whereas in the mature soil, earthworms had no effect. We conclude that earthworms have a significant, immediate effect on the litter flammability of immature soils.

2025-01-01T00:00:00Z Novotný, Petr Šída, Otakar Mikšík, Daniel Mráz, Patrik https://hdl.handle.net/20.500.14178/3726 2026-04-01T01:00:25Z 2025-01-01T00:00:00Z

Informatorium pro Repozitář skenů a fotografií herbářových položek Novotný, Petr; Šída, Otakar; Mikšík, Daniel; Mráz, Patrik Herbářové sbírky mají ve svých depozitech velké množství herbářových položek, které je možné studovatprezenčně, nebo po jejich zapůjčení. Jejich digitalizace a následné zpřístupnění prostřednictvím onlineplatforem umožní daleko širší využití, a zároveň to slouží jako jakási pojistka pro případ "kdyby se něconedejbože stalo"; takové zpřístupnění rovněž významně snižuje riziko poškození fyzického herbářovéhomateriálu plynoucího z manipulace s ním či z jeho přepravy. Digitalizace herbářových dokladů probíhá vedvou rovinách - jednak se digitalizují vlastní údaje o nálezu (přepis schedy) a také se fotí či skenují vlastnípoložky neboli specimeny. Oba tyto přístupy umožňují (mezi)národním výzkumníkům udělat si rámcovoupředstavu o datech dostupných v daném herbáři a vzájemně se doplňují. V okamžiku kdy herbář začněpořizovat skeny specimenů ve velkém rozlišení, tak záhy vzniká otázka, kde je uložit, spravovat a jak jezpřístupnit odborné veřejnosti. Odpověď na otázku "proč" tedy zní "aby bylo pro české herbáře snadné archivovata následně zpřístupňovat obrazové doklady herbářových položek", aniž by dílčí instituce museliřešit úložné místo, konektivitu a technické otázky interoperability s globálními agregátory.; Herbarium collections have a large number of herbarium items in their deposits, which can be studied in person or after borrowing them. Their digitization and subsequent access via online platforms will enable much wider use, and at the same time it serves as a kind of insurance in case "if something God forbid happens"; such access also significantly reduces the risk of damage to physical herbarium material resulting from its handling or transportation. The digitization of herbarium documents takes place on two levels - first, the actual data on the find is digitized (transcription of the schedule) and the actual items or specimens are also photographed or scanned. Both of these approaches allow (inter)national researchers to get a general idea of the data available in a given herbarium and complement each other. The moment the herbarium starts taking high-resolution scans of specimens, the question soon arises of where to store them, manage them and how to make them available to the professional public. The answer to the question "why" is therefore "to make it easy for Czech herbaria to archiveand subsequently make available image evidence of herbarium items", without sub-institutions having todeal with storage space, connectivity and technical issues of interoperability with global aggregators.

2025-01-01T00:00:00Z