Czech White-Nose Syndrome Team together with international collaborators discovered mechanisms of tolerance that protect Palearctic bats from white-nose syndrome (WNS), the disease that caused mass die-off in North America. The discovery raises hope for a better future of bats in North American ecosystems. White-nose syndrome (WNS) is caused by a generalist pathogen Pseudogymnoascus destructans with the worst possible characteristics of an infectious fungal agent. The generalist nature of the WNS fungus means that it can infect any bat hibernating in a contaminated cave or mine and, moreover, it may remain viable and virulent, waiting for its hosts until the next hibernation period. Harmless to humans, the WNS fungus kills hibernating North American bats in winter. However, loss of voracious insectivorous bats from agricultural ecosystems may result in economic costs required for increased pest control. Without mass die-offs of bats harbouring the WNS agent in Europe, the response to disease is an enigma. To study the survival crossroads, the Czech WNS Team focused on the relationship between pathogen quantity and disease under natural conditions. High disease prevalence together with high fungal loads in absence of bat population declines in Eurasia indicates disease tolerance mechanisms, where hosts limit harm inflicted by the pathogen but do not hinder its growth. The tolerance mechanisms revealed by the Czech WNS Team is a function of bat adaptation to the presence of the pathogen. and Natália Martínková.
Článek přináší přehled současných znalostí o fylogenezi mnohobuněčných živočichů, tak jak vycházejí ze současného fylogenomického výzkumu. Zvláštní pozornost je věnována skupinám s konfliktním postavením (Ctenophora, Xenacoelomorpha, Bryozoa) a skupinám, o jejichž postavení dosud nevíme téměř nic (Dendrogramma, Dicyemida, Orthonectida)., We present an overview of current knowledge on the phylogeny of multicellular animals, based on current phylogenomic research. This overview pays special attention to groups with uncertain positions (Ctenophora, Xenacoelomorpha, Bryozoa) and groups whose position is still largely unknown (Dendrogramma, Dicyemida, Orthonectida)., and Jan Zrzavý.
a1_Attention should be paid to ozone (O3) sensitivity of greening plant since ground-level O3 concentrations are increasing especially in urban and suburban area. We studied the ecophysiological responses to elevated O3 of four shrub species [Euonymus bungeanus Maxim. (EB), Photinia × fraseri (PF), Chionanthus retusus Lindl. & Paxt. (CR) and Cornus alba L. (CA)], which are often used for garden greening in China. Saplings of those species were exposed to high O3 concentration (70 nmol mol-1, 7 h d-1 for 65 d) in open-top growth chambers. Responses to O3 were assessed by gas exchanges, chlorophyll (Chl) fluorescence and dry mass. We found that elevated O3 significantly decreased lightsaturated net photosynthetic rate (PNsat), transpiration rate (E) and stomatal conductance (gs). The ratio of intercellular CO2 to ambient CO2 concentration (Ci/Ca) did not reduce under O3 fumigation which suggested that the O3-induced depressions of P Nsat under O3 fumigation were probably due to limitation of mesophyll processes rather than stomatal limitation. High O3 exposure also significantly depressed the maximum efficiency of photosystem II (PSII) photochemistry in the dark-adapted state (Fv/Fm) which meant the O3-induced photoinhibition. Both root dry mass and root/shoot ratios were significantly decreased under ozone fumigation, but the total mass was unchanged. The responses of gas exchange such as PNsat in these four shrubs to O3 exposure were species-specific. Highest loss of PNsat was observed in EB (-49.6%), while the CR had the lowest loss (-36.5%). Moreover, the O3-exposed CR showed similar gs as CF, reflecting that its O3 flux might be unchanged under elevated O3 environment. Ozone drastically decreased actual quantum yield of PSII (ΦPSII) and electron transport rate (ETR) in EB while increased ΦPSII and ETR in CR., a2_Furthermore, the relative losses in P Nsat positively correlated with the relative decreases in ΦPSII and ETR which indicated that the impairment of photosynthesis was probably affected by the light reaction process. The light reaction of EB was impaired most seriously but that of CR was not damaged. All results indicated that EB was probably the most sensitive shrub species to O3 while CR the most tolerant one. Therefore, CR might be an ideal choice for greening in ozone-polluted areas., L. Zhang ... [et al.]., and Obsahuje bibliografii
a1_Low light availability under a forest canopy often limits plant growth; however, sudden increase in light intensity may induce photoinhibition of photosynthesis. The aim of this study was to evaluate the ecophysiological changes that occur in potted plants of Minquartia guianensis and Swietenia macrophylla during the acclimation process to full sunlight. We used six full-sun independent acclimation periods (30, 60, 90, 120, 150, and 180 days) and a control kept in the shade. Shading was obtained by placing plants under the canopy of a small forest. The Fv/Fm ratio, net photosynthetic rate (PN), the maximum carboxylation velocity of Rubisco (Vcmax), maximum electron transport rate (Jmax), specific leaf area (SLA), and growth were assessed at the end of each of the six acclimation periods. Plant exposure to full sunlight caused a sudden decrease in the Fv/Fm ratio (photoinhibition) particularly in Minquartia. Photooxidation (necrotic patches) of the leaf tissue was observed in upper leaves of Minquartia. The higher PN values were observed in Swietenia under full sun, about 12 μmol(CO2) m-2 s-1. Vcmax25 values were higher after 90 days of acclimation, about 14 μmol(CO2) m-2 s-1 for Minquartia, and 35 μmol(CO2) m-2 s-1 for Swietenia. At the end of a 180-d acclimation period Jmax25 was 35 μmol(electron) m-2 s-1 for Minquartia and 60 μmol(electron) m-2 s-1 for Swietenia. SLA was higher in Swietenia than in Minquartia. In Minquartia, monthly rate of leaf production per plant (MRLP) was positive (0.22 leaf month-1) after four months in the open. Whereas, in Swietenia MRLP was positive (0.56 leaf month-1) after an acclimation period of two months. After six months in the open, height growth rates were 3.5 and 28 mm month-1 for Minquartia and Swietenia, respectively., a2_The greater acclimation capacity of Swietenia was associated to an enhanced photosynthetic plasticity under full sun. In Minquartia, transition to full-sun conditions and lack of physiological adjustment resulted in severe photoinhibition and loss of leaves., G. F. C. Azevedo, R. A. Marenco., and Obsahuje bibliografii
Užovka stromová (Zamenis longissimus) patří mezi kriticky ohrožené druhy naší fauny. V České republice se průkazně vyskytuje pouze ve třech oblastech, přičemž nejzranitelnější je populace v údolí řeky Ohře v západních Čechách, izolovaná stovky kilometrů od souvislého areálu druhu. V letech 2005-07 jsme v Poohří provedli systematický výzkum hadů pod záštitou Fakulty životního prostředí České zemědělské univerzity v Praze a Agentury ochrany přírody a krajiny ČR. Jedinci užovky stromové byli po odchycení změřeni, zváženi, označeni pomocí zástřihů na břišních štítcích (odebrané části štítků posloužily pro analýzu DNA) a detailně vyfotografováni se zaměřením na individuální charakter ošupení (folidózu) hlavy. Na základě zpětných odchytů pak byla odhadována početnost zdejší populace. Během tříletého sledování jsme takto označili a zdokumentovali celkem 432 exemplářů užovky stromové. Jeden ze současných projektů záchranného programu pro užovku stromovou zahrnuje i další odhad početnosti spojený s individuálním značením. Tato aktivita se opakuje zhruba po 10 letech a cílem je zaznamenat změny v početnosti jedinců. V dubnu 2015 se podařilo opětovně odchytit samce označeného v prvním výzkumu pod pořadovým číslem 54. Během výzkumů jsme ho chytili 10x (5x v r. 2005, 2x v r. 2006, 2x v r. 2007 a 1x v r. 2015). To umožnilo zodpovězení i nastolení různých otázek souvisejících např. s věkem a rychlostí růstu., The Aesculapian snake (Zamenis longissimus) is a critically endangered species of Czech fauna. In the Czech Republic it demonstrably occurs in three areas. Its population is most vulnerable in the Ohře river valley in western Bohemia, systematic research into which is presented here. During our three-year research we determined and documented the size and weight of 432 Aesculapian snakes, as well as performing DNA analysis and taking photographs of the individual nature of the scaliness involved. An estimate was made of population figures based on repeated captures., and Karel Janoušek, Radka Musilová, Vít Zavadil.
Jezerní sedimenty jsou ideálním přírodním archivem, který zachycuje minulé změny nejen samotného jezera, ale i okolního prostředí. Jsou zároveň jedinečné tím, že se v nich zachovávají zbytky těl různých organismů, z čehož lze zrekonstruovat druhové složení celého jezerního ekosystému. Zjištěné druhy nám také poskytují informace o životním prostředí v minulosti. Díky postupnému usazování jezerního sedimentu v průběhu holocénu tak můžeme zaznamenat nejen dlouhodobý vývoj rostlinných společenstev, ale i přírodních podmínek v horizontu tisíců let. V jezeře Šúr se během pozdního glaciálu vyskytovaly vodní rostliny rdesty, stolístky a parožnatky. Od časného holocénu se začaly objevovat na živiny a teplo náročnější druhy, jako např. šejdračka bahenní či růžkatce a během středního holocénu v jezeře expandovala kotvice plovoucí a lekníny. Na konci středního holocénu a během pozdního holocénu postupně došlo k zaplnění jezera organickým materiálem a vzniku ostřicové slatiny a posléze olšového lesa., Lake sediments are natural archives of past changes not only in the lake itself, but also in its surroundings. They preserve remains of numerous organisms, from which the species composition of the entire lake ecosystem can be reconstructed, providing information about the past environment. Thanks to gradual deposition of sediment in the lake Šúr (western Slovakia) during the Holocene period, both the long-term development of plant communities and the environmental conditions over thousands of years can be reconstructed. During the succession, aquatic communities were replaced by sedge fen and alder forest., and Anna Potůčková.
The current laboratory study was designed to evaluate the effect of abiotic and biotic factors such as temperature, light intensity, relative humidity and host age on biological and ecological characteristics of Aphelinus asychis (Walker) parasitizing Aphis gossypii (Glover). The traits studied were developmental duration, mortality, sex ratio, longevity, fecundity and host feeding. A. asychis can completely develop and reproduce at temperatures 18°C and 30°C, light intensities of 1000 and 7000 lux and relative humidities of 30% and 60%. Temperature had a significant effect on the developmental duration as well as on the percentage and longevity of females, while mortality from mummification to emergence, fecundity and host feeding were only slightly affected. Relative humidity only affected the developmental duration of A. asychis. Light intensity had mostly affected the biological and ecological traits of A. asychis. High light intensity resulted in a shorter developmental duration, higher incidence of females and longer life span of the female parasitoid. A high tolerance to climatic variations and life cycle well adapted to this aphid host are properties that make it likely that A. asychis could be used for the biological control of the cotton aphid in greenhouses.
Příspěvek se věnuje způsobu života čichavce líbajícího (Helostoma temminkii), jednoho ze zajímavých druhů labyrintních ryb. Popisuje způsob jejich života a také jejich využití. Jde o sladkovodní konzumní ryby, jejichž domovinou je jihovýchodní Asie. Své místo zaujaly také v akvaristice. Málo známý je i zajímavý způsob rozmnožování čichavce líbajícího chovaného v zajetí, který zachycují fotografické záběry při nočním tření., This article describes lifestyle and the use of the Kissing Gourami (Helostoma temminkii), one of the labyrinth fish. These edible freshwater fish native to south-east Asia are occasionally seen in aquaristics. The interesting way in which the Kissing Gourami breeds in captivity has only rarely been documented by photos because of its night time spawning., and Jaroslav Eliáš.