After the formulation of the photosynthetic unit (PSU) concerning the cooperation of 2400 chlorophyll molecules in the reduction of one molecule of C02 by Emerson and Arnold in 1932, the search for a morphological expression of the functional unit began. The quantasome hypothesis is an attempt to relate the structure visible in the electron microscope, the quantasome, and the PSU. The term 'quantasome' was introduced by Park and Calvin as a name for grana subunits. The quantasomes were regarded as the main integral parts of the grana lamellae in the protein lipid layers. Yet it soon became clear that a morphological mit such as the quantasomes did not exist. Nevertheless, the term was still used in various applications till the eighties.
The Czech dissident movement included thinkers who searched for a morally pure, parallel polis, and who felt comfortable within its isolation. The philosophers of Charter 77 (Jan Patočka and Ladislav Hejdánek especially), by contrast, rejected the idea of being morally superior to their opponents. It is interesting to consider where Václav Havel stands at this crossroads. Havel very much cooperated with the above-mentioned philosophers and was inspired by them in his own writing and agency. On the other hand, Havel undoubtedly performed a certain moral-existential concept of dissent. In this paper I examine Havel’s existential concept. In particular, after distinguishing between two existential approaches in Havel’s writings, I analyse two fundamental philosophical critiques of Havel in the work of Ladislav Hejdánek. According to Hejdánek, Havel 1) identifies intellectuals with non-politicians, i.e. he is governed by the incorrect dualism of the political versus the non-political, and 2) is self-focused and moralising, i.e. he keeps too much within his own self (subjectivity) and “a given” (existent, objective) world. Given this critique, I will systematise Hejdánek’s objections and suggested solutions. In the first case, I see the solution in a more detailed distinction: we should distinguish between politics and non-politics (intellectuals) but also non-political politics. In the second case, we should look for the essence (focal point) of man not in his morality but outside it: man should orient himself “out of his self”.
This paper discusses the strengths and weaknesses of pan-European datasets, in particular ECHP and EU-SILC, for research in housing. Although ‘housing’ is a complex topic when studied from a European comparative perspective, I argue that there is no inherent reason why housing should be less amenable to cross-national research than other equally complex topics in comparative social science research, such as research into family change and stability, or the impact of educational systems on social stratification. Given appropriate theory, conceptualisation and contextualisation, along with strong methodologies, meaningful and informative research in housing with ECHP and EU-SILC are possible. There are however a number of limitations, which are mainly related to the fact that both datasets are geared towards the ‘production’ of a ‘system of social indicators’ informing European and national governments. Because of these limitations, ECHP and in particular EU-SILC are less attractive and less useful for academic research then they could potentially be.
The aim of this study was to check what decide about breeding success in red- backed shrike Lanius collurio: nest-site concealment or parent’s aggressive behaviour. The study was carried out in eastern Poland in 1999–2003, on study plot consisted of 855 ha of extensively agricultural landscape. The effect of nest site concealment and defence of brood by parents on breeding success was determined. In observations only natural nests were used. During the two of 10 days periods after commence of egg laying, no effect of index nest concealment and index of parents aggressiveness was observed. However, in first seven days of life of nestlings, was noticed that breeding success was depended on aggressiveness of parents, in relation to index nest concealment. The results showed behavior (aggression) as an important factor in breeding success of the red-backed shrike.
Epileptic afterdischarges (ADs) elicited by electrical stimulation of sensorimotor cortical area were used as a model to study the role of neurotransmitter systems in cortical seizures in three age groups of developing rats. Drugs augmenting inhibition mediated by GABAA receptors were found to suppress ADs in all age groups, their activity was usually more marked in younger than in 25-day-old rat pups. Drugs potentiating GABAB receptors exhibit lower efficacy and more complicated developmental profile than GABAA-ergic drugs. Effects of an antagonist of GABAB receptor – marked prolongation of ADs in all three age groups – suggest an important role of GABAB receptors in arrest of cortical seizures. Drugs affecting glutamate receptors exhibit variable effects, usually better expressed in older animals than in 12-day-old ones. No specific role for ionotropic as well as metabotropic glutamate receptors could be predicted. Activation of adenosinergic inhibitory modulatory system also exhibited anticonvulsant action in the present model. All three neurotransmitter systems probably participate in mechanisms of generation, maintenance and arrest of cortical seizures., P. Mareš, H. Kubová., and Obsahuje bibliografii a bibliografické odkazy
The quality of stored blood can be deteriorated by hemolysis caused by free radicals. The purpose of this study was to elucidate whether neutrophile leukocytes are the source of free radicals in stored blood as in hemodialyzed patients. Resuspensions with low (LL) or high (HL) leukocyte concentrations were prepared from samples of twenty healthy volunteers. The samples were incubated for 10 days at 4 °C and then for one day at 37 °C. Markers of hemolysis and free radical metabolism were examined before and after incubation in LL and HL samples. In spite of the difference of leukocytes counts in LL and HL resuspensions (p<0.0001), the pre-incubation values of all laboratory parameters were practically identical. In post-storage samples, superoxide dismutase and glutathione peroxidase activities did not differ in either group. Reduced glutathione in erythrocytes and extracellular antioxidant capacity were insignificantly lower in HL resuspensions, but the increase of malondialdehyde was much more pronounced in the HL samples (p<0.0001). The degree of hemolysis, expressed as the extracellular increase of potassium (p<0.001), hemoglobin (p<0.05) and lactate dehydrogenase (p<0.05), was higher in the HL samples. Our results support the hypothesis that leukocytes participate in free radical production in stored blood., J. Racek, R. Herynková, V. Holeček, J. Faltysová, I. Krejčová., and Obsahuje bibliografii
The carbon dioxide concentrating system in C4 photosynthesis allows high net photosynthetic rates (PN) at low internal carbon dioxide concentrations (Ci), permitting higher PN relative to stomatal conductance (gs) than in C3 plants. This relation would be reflected in the ratio of Ci to external ambient (Ca) carbon dioxide concentration, which is often given as 0.3 or 0.4 for C4 plants. For a Ca of 360 µmol mol-1 that would mean a Ci about 110-140 µmol mol-1. Our field observations made near midday on three weedy C4 species, Amaranthus retroflexus, Echinochloa crus-galli, and Setaria faberi, and the C4 crop Sorghum bicolor indicated mean values of Ci of 183-212 µ mol mol-1 at Ca = 360 µmol mol-1. Measurements in two other C4 crop species grown with three levels of N fertilizer indicated that while midday values of Ci at high photon flux were higher at limiting N, even at high nitrogen Ci averaged 212 and 196 µmol mol-1 for Amaranthus hypochondriacus and Zea mays, respectively. In these two crops midday Ci decreased with increasing leaf to air water vapor pressure difference. Averaged over all measurement days, the mean Ci across all C4 species was 198 µmol mol-1, for a Ci/Ca ratio of 0.55. Prior measurements on four herbaceous C3 species using the same instrument indicated an average Ci/Ca ratio of 0.69. Hence midday Ci values in C4 species under field conditions may often be considerably higher and more similar to those of C3 species than expected from measurements made on plants in controlled environments. Reducing gs in C4 crops at low water vapor pressure differences could potentially improve their water use efficiency without decreasing PN.
Polycystic ovary syndrome (PCOS), the most common endocrinopathy in women (with a prevalence of 5-10 %), is characterized by hormonal and metabolic imbalance. Complexity of symptoms of close relatives of women with PCOS and genetic autosomal trait initiated a hypothesis about the existence of a male equivalent of PCOS. Premature alopecia was suggested as one of the signs of a male phenotype of this syndrome. The present study investigated a group of 30 men, in which premature hair loss started before 30 years of age. In all patients, their hormonal profile was determined. It was possible to form two subgroups. The first one showed similar hormonal changes as women with PCOS, the other had either no anomalies in steroid spectrum or just only lower level of sexual hormones binding globulin (SHBG). Both subgroups did not differ in either BMI or age. In all men with premature alopecia insulin tolerance test was also carried out and the occurrence of allele 3 INS VNTR was investigated, which is one of the candidate genes for PCOS. The subgroup with hormonal changes resembling those of women with PCOS showed a significantly higher insulin resistance than the group without these changes. About one third of the premature balding men showed the combination of hormonal shifts and higher insulin resistance. This frequency corresponds to the prevalence of PCOS in women. There was no significant difference between the two subgroups in the occurrence of allele 3 INS VNTR.
High temperature is a common constraint during anthesis and grain-filling stages of wheat leading to huge losses in yield. In order to understand the mechanism of heat tolerance during monocarpic senescence, the present study was carried out under field conditions by allowing two well characterized Triticum aestivum L. cultivars differing in heat tolerance, Hindi62 (heat-tolerant) and PBW343 (heat-susceptible), to suffer maximum heat stress under late sown conditions. Senescence was characterized by measuring photosynthesis related processes and endoproteolytic activity during non-stress environment (NSE) as well as heat-stress environment (HSE). There was a faster rate of senescence under HSE in both the genotypes. Hindi62, having pale yellow flag leaf with larger area, maintained cooler canopy under high temperatures than PBW343. The tolerance for high temperature in Hindi62 was clearly evident in terms of slower green-leaf area degradation, higher stomatal conductance, higher stability in maximum PSII efficiency, Rubisco activity and Rubisco content than PBW343. Both the genotypes exhibited lower endopeptidase activity under HSE as compared to NSE and this difference was more apparent in Hindi62. Serine proteases are the predominant proteases responsible for protein degradation under NSE as well as HSE. Flag leaf of both the genotypes exhibited high-molecular-mass endoproteases (78 kDa and 67 kDa) isoforms up to full grain maturity which were inhibited by specific serine protease inhibitor in both the environments. In conclusion, the heat-tolerant Hindi62 exhibited a slower rate of senescence than the heat-susceptible PBW343 during HSE, which may contribute towards heat stability. and S. Chauhan ... [et al.].
We tested the hypothesis that males of meadow pipits (Anthus pratensis) respond differentially to simulated territorial intrusions (song playback + bird model) by conspecific, related (tree pipit, Anthus trivialis), and unrelated individuals (willow warbler, Phylloscopus trochilus), and evaluated the effect of playback order. All tested males responded aggressively to the conspecific playback; reactions to heterospecific stimuli occurred only after previous excitation by the conspecific song and dummy, and were usually weaker. Apparently, although males were able to discriminate between playbacks, excitation by intrusion of a conspecific rival elicited an aggressive reaction to otherwise neutral stimuli. Reactions to heterospecific playbacks closely following the conspecific one did not differ significantly between congeneric and unrelated species. The response to a subsequent heterospecific stimulus, however, was taxon-dependent: congeneric species elicited a significantly stronger reaction than an unrelated one. We presume that this was due to the morphological similarity between pipits, and that the more intensive reaction could have been caused by stronger visual stimulus from the respective model. We discuss the potential benefits as well as limitations of using models (dummies) in playback experiments, and suggest that overexcitation by previous stimuli should be considered during experimental setup and data analysis in studies focusing both on interspecific aggressiveness and on neighbour-stranger interactions.