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.
By use of plastic or rubber admixtures in the stamped charges, it is possible to affect the properties of tar, in contrast to the calorific value of resulting coking gas; further, it was found that the reactivity- and strength parameters of the obtained blast-furnace coke are good or acceptable. Unused plastics or rubber can economize on part of the coal used in a stamped charge. Additions of both light and heavy plastics can be used up to 5 % of a charge weight; in the case of rubber it is not advisable to exceed 2 wt.-% in a charge. In contradiction to the other methods, which process the unused plastics of up to a content of 1 % in a charge, it is possible, in the case of used stamping method, to process even 2 % or more., Pavel Straka., and Obsahuje bibliografické odkazy
The abnormal proliferation of vascular smooth muscle cells (VSMC) is thought to play a role in the pathogenesis of atherosclerosis. Adipocytes produce several bioactive paracrine substances that can affect the growth and migration of VSMCs. Our study focuses on the direct effect of the bioactive substances in conditioned media (CM) that was obtained by incubation with primary adipocyte-derived cell lines, including cell lines derived from both preadipocytes and from more mature cells, on the proliferation rate of human aortic smooth muscle cells (HAoSMCs). We used a Luminex assay to measure the adipokine content of the CM and showed that there was a higher concentration of monocyte chemoattractant protein-1 in renal preadipocyte-CM compared with the HAoSMC control (p<0.5). The addition of both renal preadipocyte- and epicardial adipocyte-CM resulted in the elevated production of vascular endothelial growth factor compared with the control HASoSMC CM (p<0.001). The adiponectin content in renal adipocyte-CM was increased compared to all the remaining adipocyte-CM (p<0.01). Moreover, the results showed a higher proliferation rate of HAoSMCs after co-culture with epicardial adipocyte-CM compared to the HAoSMC control (p<0.05). These results suggest that bioactive substances produced by adipocytes have a stimulatory effect on the proliferation of VSMCs., J. Ždychová, S. Čejsková, I. Králová Lesná, A. Králová, J. Malušková, L. Janoušek, L. Kazdová., and Obsahuje bibliografii
On the basis of laboratory and industrial experiments it was found that rubber can be treated by co-gasification with brown coal, namely in the process of the oxygen-steam pressure gasification in a moving bed (Lurgi gasification process). Considering the very low reactivity of the residual char from rubber, the optimal content of the rubber particles in the mixture being gasified should probably not exceed 10 wt.-%, but short-term increases in the proportion of these particles (up to 20 wt.-%) will not cause technological problems or significant economic losses., Pavel Straka, Vlastimil Kříž and Zdeněk Bučko., and Obsahuje bibliografii
Photosynthesis, photorespiration, and chlorophyll (Chl) fluorescence in green and red Berberis thunbergii leaves were studied with two different measuring radiations, red (RR) and "white" (WR). The photosynthetic and photorespiration rates responded differently to the different radiation qualities, which indicate that the carboxylase and oxygenase activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) were affected. Differences in photosynthetic rate between the two color leaves were less under RR than under WR. However, this reduced difference in photosynthetic rate was not correlated with the stomatal response to the measuring radiation qualities. Compared with the WR, the RR reduced the differences in dark-adapted minimum and maximum fluorescence, steady-state fluorescence, light-adapted maximum fluorescence, and actual photochemical efficiency (ΦPS2) of photosystem 2 (PS2), but enlarged the difference in non-photochemical quenching between the two color leaves. Differences in both maximum quantum yield of PS2 and ratio of ΦPS2 to quantum yield of CO2 fixation between the two color leaves were similar under the two measuring radiations. To exclude disturbance of radiation attenuation caused by anthocyanins, it is better to use RR to compare the photosynthesis and Chl fluorescence in green versus red leaves. and P.-M. Li ... [et al.].
Gas exchanges and leaf water potential (Ψw) of six-years-old trees of fourteen Prunus amygdalus cultivars, grafted on GF-677, were studied in May, when fruits were in active growing period, and in October, after harvesting. The trees were grown in the field under rain fed conditions. Predawn Ψw showed lower water availability in October compared with May. The lowest Ψw values at midday in May increased gradually afterwards, while in October they decreased progressively until night, suggesting a higher difficulty to compensate the water lost by transpiration. However, relative water content (RWC) measured in the morning was similar in both periods, most likely due to some rainfall that occurred in September and first days of October that could be enough to re-hydrate canopy without significantly increasing soil water availability. The highest net photosynthetic rate (PN) was found in both periods early in the morning (08:00-11:00). Reductions in PN from May to October occurred in most cultivars except in José Dias and Ferrastar. In all cultivars a decrease in stomatal conductance (gs) was observed. Photosynthetic capacity (Pmax) did not significantly change from spring to autumn in nine cultivars, revealing a high resistance of photosynthetic machinery of this species to environmental stresses, namely high temperature and drought. Osmotic adjustment was observed in some cultivars, which showed reductions of ca. 23 % (Duro d' Estrada, José Dias) and 15 % (Tuono) in leaf osmotic potential (Ψπ). Such decreases were accompanied by soluble sugars accumulation. The Portuguese cultivar José Dias had a higher photosynthetic performance than the remaining genotypes. and M. C. Matos ... [et al.].
Most organisms inhabiting earth feed directly or indirectly on the products synthesized by the reaction of photosynthesis, which at the current atmospheric CO2 levels operates only at two thirds of its peak efficiency. Restricting the photorespiratory loss of carbon and thereby improving the efficiency of photosynthesis is seen by many as a good option to enhance productivity of food crops. Research during last half a century has shown that several plant species developed CO2-concentrating mechanism (CCM) to restrict photorespiration under lower concentration of available CO2. CCMs are now known to be operative in several terrestrial and aquatic plants, ranging from most advanced higher plants to algae, cyanobacteria and diatoms. Plants with C4 pathway of photosynthesis (where four-carbon compound is the first product of photosynthesis) or crassulacean acid metabolism (CAM) may consistently operate CCM. Some plants however can undergo a shift in photosynthetic metabolism only with change in environmental variables. More recently, a shift in plant photosynthetic metabolism is reported at high altitude where improved efficiency of CO2 uptake is related to the recapture of photorespiratory loss of carbon. Of the divergent CO2 assimilation strategies operative in different oraganisms, the capacity to recapture photorespiratory CO2 could be an important approach to develop plants with efficient photosynthetic capacity. and S. K. Vats, S. Kumar, P. S. Ahuja
This article summarises the current knowledge of the rabbit coccidia and the disease they cause. Various aspects, such as life cycles, localisation in the host, pathology and pathogenicity, immunity and control, are discussed.