Genomická a transkriptomická studia u dvou druhů bublinatky (Utricularia gibba a bublinatky obecné - Utricularia vulgaris) přinesla průlomové poznatky. Ukázala, že miniaturní genom Utricularia gibba obsahuje zhruba stejný počet genů jako jiné kvetoucí rostliny a u některých genových rodin došlo k výrazné expanzi. To se týká např. genů zodpovědných za tvorbu kutikuly nebo za reakci na chitin, což souvisí s životním stylem této vodní masožravé rostliny. Současná nepřítomnost genů souvisejících s vývojem a funkcí kořene u obou druhů bublinatky naznačuje ztrátu „kořenových” genů u společného předka těchto druhů., Genomic and transcriptomic studies in Utricularia gibba and U. vulgaris have led to important discoveries. It was found that the miniature genome of U. gibba contained about the same number of genes as other angiosperms and that some gene families even expanded. For example, the genes responsible for cuticle development or the response to chitin are more numerous than in other plants, which may be related to the aquatic carnivorous lifestyle. Coincident absence of the genes associated with root development and function in U. gibba and U. vulgaris indicates the loss of the root genes already in their common ancestor., and Helena Štorchová.
Travinné ekosystémy jsou významnou součástí středoevropské krajiny. Polopřirozená travinná společenstva dnes tvoří v Evropě místa s vysokou biodiverzitou, jsou velmi náchylná k degradaci a k jejich efektivní ochraně je nutné znát vlivy různých typů managementu. Neodmyslitelnými obyvateli těchto ekosystémů jsou také zástupci rovnokřídlého hmyzu (Orthoptera), kteří zde hrají důležitou roli v potravní síti. Zároveň jsou vhodným indikátorem změn stanovištních podmínek, a to zejména struktury vegetace, čehož lze využít při zjišťování dopadů různých managementových opatření. Jedním z nejběžnějších a zároveň pro hmyz nejméně vhodných typů péče je dnes mechanizovaná seč. Nevhodná péče o travinné ekosystémy může ovlivňovat druhovou bohatost jak v měřítku lokálním tak i v měřítku krajiny. Snížení negativního dopadu seče ve prospěch biodiverzity lze docílit několika způsoby - např. zmírněnou intenzitou zásahu, a to posunutím nebo vynecháním první seče, nebo ponecháním neposečených ploch., Grasslands are an important part of the Central European landscape. Seminatural grasslands are considered to be biodiversity hotspots in Europe, with high conservation value. However, they are very unstable, and for their effective conservation it is necessary to know how different management systems affect the progression of the ecosystem. Orthopterans play an important role in the food web and they are also a good indicator of changes in habitat conditions, particularly in the vegetation structure, which can be used in determining the impact of different types of conservation management. Nowadays, one of the most common and least insect-friendly type of care is mechanized hay harvesting. Improper care can affect the species richness (both, on the local and landscape scale). The negative impact of mowing can be reduced in favour of biodiversity in several ways, as described (e.g., mitigating the intensity of the process by delaying or omitting the first mowing, or leaving uncut refuges)., and Oto Kaláb.
Článek shrnuje současné znalosti o taxonomickém postavení, rozšíření a ekologii žížaly Allolobophora hrabei a o jejím vlivu na stepní ekosystémy. A. hrabei dnes chybí na většině lokalit, kde se historicky vyskytovala a je nutno ji považovat za ohrožený druh. Na místech s dostatečně velkou populací může významně ovlivňovat půdní vlastnosti i společenstva ostatních půdních organismů., This contribution summarizes current knowledge about the taxonomic position, distribution and ecology of the earthworm Allolobophora hrabei and its role in fragile fragments of central European steppe ecosystems. Nowadays, A. hrabei should be classified endangered as it is absent at most of its historical sites. Nevertheless, it may significantly affect both soil parameters and other soil organisms at the sites inhabited by larger populations., and Václav Pižl.
Příspěvek shrnuje dosavadní poznatky o skupině mořských bezobratlých - nohatkách (Pantopoda). Přibližuje jejich ekologii, morfologii, rozmnožování a fylogenezi. Zároveň ukazuje preparáty nohatek uložené ve sbírkách Národního muzea v Praze., This contribution summarizes the current knowledge about the sea spiders (Pantopoda). It is focused mainly on their ecology, morphology, reproduction and phylogeny. The review is also accompanied by figures of the specimens deposited in the National Museum in Prague., and Petr Dolejš.
During shock, prognosis of a patient depends largely on intestinal barrier function. The potency of gut epithelium to represent an obstacle to toxins is determined by the blood supply. All established methods of mucosal function determination necessitate the functional involvement of bloodstream. Microdialysis allows monitoring of extracellular substances in the gut submucosa, but its potential use for gut barrier integrity assessment is unknown. Twelve rats underwent perfusion of the descending colon either with 20 % ethanol or control medium (vehicle). Both media contained equal amounts of a radioactive tracer substance (51Cr-EDTA). Mucosal permeability for 51Cr-EDTA was assessed by microdialysate to luminal perfusate activity ratios. Sampling was performed using the colon submucosal microdialysis technique. The group subjected to ethanol treatment had profound macro- and microscopical alterations in perfused colonic segment associated with a significant increase in tracer permeability during ethanol exposure (2.354±0.298 % for ethanol as opposed to 0.209±0.102 % for control group, p<0.01), which remained elevated for 60 min after cessation of ethanol administration (3.352±0.188 % for ethanol compared to 0.140± 0.0838 % for the control group, p<0.001). Submucosal microdialysis with radioactive tracer substance can be considered a feasible and advantageous alternative of gut barrier function estimation. Parallel monitoring of local tissue chemistry with this method remains a challenge in the future., N. Cibiček, H. Živná, Z. Zadák, J. Kulíř, E. Čermáková, V. Palička., and Obsahuje bibliografii a bibliografické odkazy
Tomato (Lycopersicon esculentum Mill. cv. Pearson) plants were grown in growth chambers for 25 days with cadmium (Cd) and then exposed briefly to ozone (O3). Gas exchange, chlorophyll a fluorescence, and pigment composition were analysed in leaves at the end of the treatment to assess the effects of a single pollutant and their combination on photosynthesis. The CO2 assimilation rate was dramatically reduced in plants subjected to the combined treatment, while the single effect of Cd appeared less severe than that of O3. The decline of CO2 photoassimilation found in all
O3-exposed plants was attributed to both stomatal and nonstomatal limitations. Tomato plants seemed to detoxify Cd to a great extent, but this resulted in growth suppression. In response to O3 exposure, the plants protected their photosystems by heat dissipation of excess energy via the xanthophyll cycle. Cd combined with O3 affected adversely this cycle resulting in an increase in photosynthetic performance under the same experimental light conditions., E. Degl’Innocenti, A. Castagna, A. Ranieri, L. Guidi., and Obsahuje bibliografii
Drought stress is one of the main environmental factors limiting plant growth and productivity of many crops. Elevated carbon dioxide concentration (eCO2) can ameliorate, mitigate, or compensate for the negative impact of drought on plant growth and enable plants to remain turgid and functional for a longer period. In order to investigate the combined effects of eCO2 and drought stress on photosynthetic performance and leaf structures, we analyzed photosynthetic characteristics and structure and ultrastructure of cucumber leaves. The decline in net photosynthetic rate under moderate drought stress occurred due to stomatal limitation alone, while under severe drought stress, it was the result of stomatal and nonstomatal limitations. Conversely, eCO2 improved photosynthetic performance under moderate drought stress, increased the lengths of the palisade cells and the number of chloroplasts per palisade cell under severe drought stress, and significantly increased the grana thickness under moderate drought stress. Additionally, eCO2 significantly decreased stomatal density, stomatal widths and stomatal aperture on the abaxial surface of leaves under moderate drought stress. In conclusion, eCO2 can alleviate the negative effects of drought stress by improving the drought resistance of cucumber seedlings through stomatal modifications and leaf structure., B. B. Liu, M. Li, Q. M. Li, Q. Q. Cui, W. D. Zhang, X. Z. Ai, H. G. Bi., and Obsahuje bibliografii
Geitlerinema amphibium (BA-13), mat-forming cyanobacterium from the southern Baltic Sea, was grown at three irradiances [5, 65, and 125 μmol(photon) m-2 s-1] and three temperatures (15, 22.5, and 30°C). To determine the effect of the investigated factors and their interaction on culture concentration, pigment content, and photosynthetic parameters of cyanobacterium, factorial experiments and two-way analysis of variance (ANOVA) were carried out. Both chlorophyll (Chl) a and phycobilins (PB) were influenced by the irradiance and temperature, but stronger effect was noted in the case of the former one. Chl a and PB concentration per 100 μm of filament dropped above 4-fold with the increasing irradiance. The ratios between individual carotenoids [β-carotene, zeaxanthin, and myxoxanthophyll (Myx)] and Chl a increased significantly with an increase in the irradiance. The greatest fluctuations were observed in the ratio of Myx to Chl a (above 10-fold). Thus, Myx was suggested as the main photoprotective carotenoid in G. amphibium. Based on photosynthetic light response (PI) curves, two mechanisms of photoacclimation in G. amphibium were recognized: a change of photosynthetic units (PSU) number and a change of PSU size. These two mechanisms constituted the base of significant changes in photosynthetic rate and its parameters, such as the compensation point (PC), the initial slope of photosynthetic curve (α), saturation irradiance (EK), maximal photosynthetic rate (Pmax), and dark respiration rate (RD). The greatest changes were observed in PC values (about 15-fold within the range of the factors tested). Studied parameters showed a wide range of changes, which might indicate G. amphibium ability to acclimatize well to irradiance and temperature, and indirectly might explain the successful growth of cyanobacterium in dynamically changing environmental conditions., S. Jodłowska, A. Latała., and Obsahuje bibliografii
The chilling and light stresses were experimentally created to explore photosynthesis of Fraxinus mandshurica seedlings in northeast China. Net photosynthetic rate, stomatal conductance, and transpiration rate decreased significantly with the decline of temperature and light. Significant interaction effects of light and chilling were observed on gas exchange of photosynthesis. The minimal fluorescence yield of the dark-adapted state (F0) increased with increasing light and decreasing temperature. Both high and low light stresses induced the decreases of the maximal quantum yield of PSII photochemistry (Fv/Fm), photochemical quenching coefficient (qP), nonphotochemical quenching (NPQ), and electron transport rate. Decline of Fv/Fm and increased F0 were observed under decreasing temperatures. Decreased NPQ and qP at frost temperature suggest that F. mandschurica failed to dissipate excess light energy. No interactive effects of chilling and light on chlorophyll fluorescence parameters suggests that F. mandschurica seedlings might be adapted to combined stresses of light and chilling., X. F. Li, L. Jin, C. Y. Zhu, Y. J. Wen, Y. Wang., and Obsahuje bibliografii