Retroviry jsou RNA viry, které se replikují v hostitelské buňce. Využívají enzymu reverzní transkriptázy, která přepisuje jejich RNA do DNA. Tato DNA je pak enzymem integrázou začleňována do hostitelského genomu. Pokud dojde k integraci retroviru v germinální linii, může se tento retrovirus stát součástí lidského genomu. V lidském genomu tyto retrovirové elementy (Human Endogenous Retroviruses = HERVs) tvoří až 8 % DNA. Donedávna se vědci domnívali, že HERVy jsou neaktivní, tzn. neinfikují další buňky. Během evoluce byly mnohokrát mutovány a pozbyly schopnosti genové exprese. Převažoval také názor, že HERVy nejsou ani trankribovány - nejsou přepisovány do mRNA. Ze současných výzkumů však vyplývá, že HERVy jsou hojně přepisovány v mnoha různých tkáních lidského těla. Někdy mohou z této mRNA dokonce vznikat krátké peptidy, které pak mohou buňku ovlivňovat. Jak rozsáhlý je význam transkripce, je nyní předmětem dalších zkoumání., A retrovirus is an RNA virus using its own reverse transcriptase and integrase to produce DNA from its genome and incorporate it into the host’s genome. When a retrovirus is integrated in a germ line, it can become a part of the host genome. In human genome these elements occupy about 8 % of DNA and are called human endogenous retroviruses (HERVs). During evolution they mutated and lost their function to infect other cells. They were considered inactive (not expressed), however, transcription of HERVs in many different tissues in most human cells has recently been proved., and Mirka Famfulíková, Jan Pačes.
Parliamentary elections in May 2010 ended with unexpected and somewhat revolutionary results: they brought heavy losses to all traditional established parties within the Czech party system, which appeared to be relatively stable since the second half of 1990s, two lesser parliamentary parties were eliminated from the Chamber of Deputies, and two new political parties emerged among successful subjects surpassing quite easily the existing electoral clause of five percent. The text analyzes these results, as well as some attitudes of Czech public identified by exit poll and other sociological surveys and post-election development, and it tries to answer the question, whether the elections in 2010 meant any deep and lasting shift in long-term development of the party system in the Czech Republic or whether it was rather an incidental anomaly without persistent impact on the party system, which will gradually restore itself more or less in the shape that characterized it for one and half of decade before the elections in 2010., Jan Červenka., and Obsahuje seznam literatury
V souvislosti s ukončením procesu hodnocení výzkumné činnosti pracovišť Akademie věd České republiky za léta 2005-09 se hodně času věnovalo diskuzím nad budoucím směrováním Akademie věd ČR. Základním cílem je zvýšení vědeckého výkonu Akademie věd a jejích jednotlivých ústavů vytvořením koherentního programu AV ČR jako celku, který by zahrnoval aktuální trendy světové vědy a vývoje poznání a zároveň reagoval na základní společenské výzvy v oblasti vědy a výzkumu. Přípravu této strategie lze vnímat jako pokračování pohybu Akademie věd ve směru nastoupeném po mimořádném Akademickém sněmu v červnu 2009, kdy byla v novodobé historii České republiky poprvé ohrožena její existence., In connection with the completion of the evaluation process for research activities at our institutes for 2005-09, we have devoted a great deal of time to discussions of the future direction of AS CR. The fundamental aim is to raise the scientific performance of AS CR and its institutes by creating a coherent programme for AS CR as a whole, reflecting current trends in world science and development of knowledge and at the same time reacting to the essential social challenges in science and research. I perceive the preparation of the Strategy as a continuation of the shift in direction taken after the extraordinary Academy Assembly in June 2009, when its existence was in jeopardy for the first time in the modern history of the Czech Republic., and Jiří Drahoš.
Článek vychází z pozorování výskytu kobylky malé (Phaneroptera nana) v centru Prahy. Představuje blíže tento druh, jeho rozšíření, prazskou mikropopulaci a poznatky z chovu v insektáriu., This article is based on observations of the Mediterranean Katydid (Phaneroptera nana) in the centre of Prague. It presents the species, its spread, its Prague micropopulation and information on insectarium breeding in some detail., and Pavel Pecina.
Střevlík uherský (Carabus hugaricus hungaricus) je druhem dlouhostébelných panonských stepí. Patří mezi zvláště chráněné brouky a je rovněž druhem evropsky významným. V České republice přežívá už pouze na Pouzdřanské stepi a na Pálavě. V článku shrnujeme výsledky výzkumů jeho stanovištních preferencí, demografie a mobility, diskutujeme možnosti jeho ochrany a zároveň se dotýkáme bolestivého tématu ochranářské péče o lokality tohoto druhu., The Carabus hungaricus ground beetle is a highly endangered, dry-grassland specialist listed in the EU Habitats Directive. In the Czech Republic, the beetle survives on the last two sites including the Pouzdřany steppe, and the Pálava hills. Here we report results of extensive mark-recapture studies of this species, including its habitat preference, demography, and dispersal abilities. Furthermore, we discuss the options for its conservation and conservation management of the two inhabited sites., Lukáš Čížek ... [et al.]., and Pokračování čl. na str. CXV kuléru Živy 5/2014
Phoridae (scuttle flies) are widely distributed, occur in many types of habitats and are ecologically versatile, which makes them an excellent bioindicator group for evaluating faunal diversity. The structure of scuttle fly communities was compared in two Mediterranean habitats in the Montseny Natural Park (Catalonia, Spain) that differ in vegetation and microclimate: beech forest and highland scrubland. 3684 male individuals belonging to 135 species of scuttle flies were identified. Scuttle flies were more abundant in beech forest than scrubland. Observed and estimated species richness were lower in scrubland than in beech forest, while diversity was similar in both habitats. Community evenness was greater in scrubland than beech forest. Therefore, the percentage of dominant and subdominant species was higher in scrubland than beech forest, while the percentage of rare species was higher in beech forest than scrubland. Scuttle fly species composition was significantly different in the two habitats, but it was similar among plots within the same habitat. Megaselia pectoralis (Wood, 1910) and Megaselia subpleuralis (Wood, 1909) were the dominant species in beech forest, while Megaselia pusilla (Meigen, 1830), Megaselia pumila (Meigen, 1830), Megaselia superciliata (Wood, 1910) and Megaselia diversa (Wood, 1909) were the dominant species in scrubland. Trophic specialization was higher in beech forest than scrubland. Saprophages were the dominant trophic group in beech forest, while fungivores and polyphages were dominant in scrubland. The high biodiversity of scuttle flies recorded in the Montseny Natural Park indicates that there is also a high diversity of other taxa there and that these Mediterranean mountains are of high conservation status., Carlos García-Romera, José A. Barrientos., and Obsahuje bibliografii
Using the FLAC3D numerical simulation method, the characteristics of mining stress evolution, fault activation patterns, and fault energy evolution characteristics are simulated and analyzed in the process of the footwall and hanging wall working face heading to a normal fault. The study shows that the fault cut off the mining stress propagation of overlying strata, and the stress blocking effect due to the fault is evident. When working faces head towards a fault, the abutment pressure and the vertical stress of the surrounding rock increase first and subsequently decrease. The abutment pressure of the coal wall and fault is highest when the distances to the fault are 40 m and 30 m for the footwall and hanging wall working faces, respectively. Moreover, the hanging wall mining stress is higher than the footwall mining stress. Fault activation in high-located strata precedes that in low-located strata when working faces head towards the normal fault. Energy is gradually accumulated before unstable fault events take place because of mining, and fault instability quickly releases a lot of energy. The mining stress concentration and fault activation due to faults easily result in rock bursts and mine seismicity, Wu Quan-sen, Jiang Li-shuai and Wu Quan-lin., and Obsahuje bibliografické odkazy