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221.
MicroRNA-451 Regulates LKB1/AMPK Signaling and Allows Adaptation to Metabolic Stress in Glioma Cells
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Michal Horsák Jana ?kodová Jan My?ák Tomá? ?ejka Vojen Lo?ek Jaroslav ?. Hlavá? 《Biologia》2010,65(6):1012-1018
Pupilla pratensis (Clessin, 1871) was recently confirmed as a distinct species based on morphological, ecological and molecular evidence. The
main purpose of this study is to publish the first reliable data on the occurrence of P. pratensis in the Czech Republic and Slovakia. The second goal is to analyse conchometry of P. pratensis, P. muscorum (L., 1758), and P. alpicola (Charpentier, 1837) to find out whether it is possible to reliably distinguish these species solely based on shell measurements.
For multidimensional analysis of shell measurement variation we used principal components analysis (PCA). We documented six
populations of P. pratensis in the Czech Republic and one in SW Slovakia. The revision of voucher material showed that all previously reported records
of P. alpicola from the Czech Republic belonged in fact to P. pratensis. This requires the exclusion of P. alpicola from the list of Czech molluscs. Based on multidimensional analysis of shell measurements it was possible to distinguish
P. pratensis from P. muscorum with no overlapping specimens. Pupilla alpicola was almost completely different from P. muscorum with only few overlapping specimens, contrary to P. pratensis which was mostly impossible to distinguish from P. alpicola based on analysed shell measurements. Shell width was the best single shell measurement for distinguishing P. pratensis and P. muscorum. Shell measurements of two Swedish populations of P. pratensis did not differ from shell variation of Czech and Slovak populations. However, Scandinavian populations displayed some differences
from central European populations in apertural barriers which are discussed in detail. Czech and Slovak populations of P. pratensis occurred in calcium-rich fen meadows which perfectly matches with site characteristics reported from Scandinavia. We assume
that the observed morphometric differences between P. pratensis and P. muscorum can be useful for distinguishing the species also outside the Czech territory and for palaeoecological studies where only
empty shells are available. Since these species occupy ecologically different habitats their reliable identification in fossil
material can improve the reconstructions of past environments. 相似文献
227.
Michal Dabrowski Norbert Dojer Malgorzata Zawadzka Jakub Mieczkowski Bozena Kaminska 《BMC systems biology》2010,4(1):86
Background
It is often desirable to separate effects of different regulators on gene expression, or to identify effects of the same regulator across several systems. Here, we focus on the rat brain following stroke or seizures, and demonstrate how the two tasks can be approached simultaneously. 相似文献228.
Aucina A Rudawska M Leski T Skridaila A Riepsas E Iwanski M 《Applied and environmental microbiology》2007,73(15):4867-4873
We report the effects of pine and oak litter on species composition and diversity of mycorrhizal fungi colonizing 2-year-old Pinus sylvestris L. seedlings grown in a bare-root nursery in Lithuania. A layer of pine or oak litter was placed on the surface of the nursery bed soil to mimic natural litter cover. Oak litter amendment appeared to be most favorable for seedling survival, with a 73% survival rate, in contrast to the untreated mineral bed soil (44%). The concentrations of total N, P, K, Ca, and Mg were higher in oak growth medium than in pine growth medium. Relative to the control (pH 6.1), the pH was lower in pine growth medium (5.8) and higher in oak growth medium (6.3). There were also twofold and threefold increases in the C content of growth medium with the addition of pine and oak litter, respectively. Among seven mycorrhizal morphotypes, eight different mycorrhizal taxa were identified: Suillus luteus, Suillus variegatus, Wilcoxina mikolae, a Tuber sp., a Tomentella sp., Cenococcum geophilum, Amphinema byssoides, and one unidentified ectomycorrhizal symbiont. Forest litter addition affected the relative abundance of mycorrhizal symbionts more than their overall representation. This was more pronounced for pine litter than for oak litter, with 40% and 25% increases in the abundance of suilloid mycorrhizae, respectively. Our findings provide preliminary evidence that changes in the supply of organic matter through litter manipulation may have far-reaching effects on the chemistry of soil, thus influencing the growth and survival of Scots pine seedlings and their mycorrhizal communities. 相似文献
229.
Michal Hájek Lubomír Tichý Brandon S. Schamp David Zelený Jan Roleek Petra Hájková Iva Apostolova Daniel Dít 《Oikos》2007,116(8):1311-1322
The Evolutionary species pool hypothesis (ESPH) predicts that historically more common habitats will be richer in species because they have had greater opportunity for the evolution of suitably adapted species. We explored the relationship between mire species richness and pH, an important environmental variable in mires, in two regions that differ in habitat pH distribution: the West Carpathians and Bulgaria. Mire habitats in both the West Carpathians and Bulgaria demonstrate support for the ESPH prediction that habitats with more common pH values host more species. We also explored the influence of habitat history by examining the distribution of generalists and specialists along gradients of habitat pH, using extensive community-level vegetation data from European mires in these two regions. We found a striking pattern with the distribution of pH-specialists having three distinct peaks in both regions, whereas the total species pool peaked in near neutral pH habitats in both regions. Because the peaks in specialist richness do not correspond to regional pH distribution patterns, we hypothesize that historical explanations may be important, and that habitats currently rich in pH-specialists may have historically acted as pleniglacial refugia for many mire species. Our findings support the general predictions of the ESPH, but further suggest that historical processes such as patterns of glacial refugia, may significantly influence contemporary species distributions and the diversity of plant species in mire habitats. 相似文献
230.
Marian Pavelka Manuel Acosta Michal V. Marek Werner Kutsch Dalibor Janous 《Plant and Soil》2007,292(1-2):171-179
The parameter Q10 is commonly used to express the relationship between soil CO2 efflux and soil temperature. One advantage of this parameter is its application in a model expression of respiration losses
of different ecosystems. Correct specification of Q10 in these models is indispensable. Soil surface CO2 efflux and soil temperature at different depths were measured in a 21-year-old Norway spruce stand and a mountain grassland
site located at the Experimental Ecological Study Site Bily Kriz, Beskydy Mts. (NE Czech Republic), using automated gasometric
systems. A time-delay and goodness-of-fit between soil CO2 efflux and soil temperature at different measuring depths were determined. Wide ranges of values for the time-delay of CO2 efflux in response to temperature, Q10 and the determination coefficient (R2) between CO2 efflux and temperature were obtained at the both sites. The values of Q10 and the CO2 time-delay increased with depth, while the R2 of the CO2-temperature relationship significantly decreased. Soil temperature records obtained close to the soil surface showed the
highest values of R2 and the lowest value of the time-delay at both sites. Measurement of soil temperature at very shallow soil layer, preferably
at the soil surface, is highly recommended to determine useable values of Q10. We present a new procedure to normalize Q10 values for soil temperatures measured at different depths that would facilitate comparison of different sites. 相似文献