Induction of the inducible form of nitric oxide synthase (iNOS) in the vascular and cardiac tissue by several inflammatory stimuli may result in the production of large amounts of nitric oxide (NO) for a sustained period. Recent data obtained in the rat aorta in which iNOS was induced by lipopolysaccharide (LPS) have demonstrated that adventitial cells represent the main site of NO production. Adventitial-derived NO can exert an immediate down-regulatory effect on smooth muscle contraction (via activation of the cyclic GMP pathway) but may also initiate longer lasting effects through the formation of NO stores within the medial layer. One candidate for such NO stores are dinitrosyl non-heme iron complexes. Low molecular weight thiols interact with preformed NO stores and promote vasorelaxation by a cyclic GMP-independent mechanism involving the activation of potassium channels. In the heart, the induction of iNOS is involved in delayed protection against ischemia-reperfusion-induced functional damages. Recent data obtained with monophosphoryl lipid A, a non-toxin derivative of LPS, strongly suggest that iNOS-derived NO in the rat heart does not act as an immediate mediator of the cardioprotection but rather as a trigger of long-term protective mechanisms. Thus, the present data reveal the important role of adventitial cells as a site of iNOS expression and activity in intact blood vessels. The induction of adaptive mechanisms in the heart and the formation of releasable NO stores in blood vessels are examples of long-term consequences of iNOS induction. These new information are relevant for a better understanding of the circumstances in which NO overproduction by iNOS may play either a beneficial or deleterious role in these tissues., B. Muller, A. L. Kleschyov, K. Gyorgy, J.-C. Stoclet., and Obsahuje bibliografii
Angiogenesis is known to be triggered by various stimuli including hypertension. It was previously found that NO-deficient hypertension is accompanied by structural remodeling of the cardiac muscle and large coronary arteries. This study was aimed to examine the qualitative subcellular alterations of capillaries in the heart of the rats treated with L-NAME (40 mg/kg/day for 4 weeks). The results showed that long-lasting inhibition of NO production induced an apparent activation of fibroblast function. This was associated with enhancement of fibrozation as well as with the induction of angiogenesis. Accordingly, fibroblasts were frequently located in the vicinity of capillary pericytes, which was followed by their detachment and migration. Moreover, besides inactive or even injured capillaries, the other ones exhibited extensive proteosynthetic activity linked to capillary growth, proliferation and migration of endothelial cells. The results strongly indicate enhanced triggering of the angiogenesis in L-NAME-induced NO-deficient hypertension., Ľ. Okruhlicová, N. Tribulová, I. Bernátová, O. Pecháňová., and Obsahuje bibliografii
Tobacco plants accumulating high levels of soluble sugars due to the cytosolic expression of an inorganic pyrophosphatase from Escherichia coli were ušed to study adaptation to the osmotic stress that these plants are continuously faced with. In the course of differential RNA screening between wild type and transgenic plants three cDNA dones could be isolated, which after sequencing were identified as pathogenesis-related proteins (PR-proteins). Two cDNAs, PRlb and PR-P, belong to the acidic PRl and PR3 groups of PR-proteins, and the third cDNA, SAR8.2, has so far been associated with systemic acquired resistance in tobacco plants. The expression of PR-proteins transcripts in generál was well correlated with the steady- state level of total soluble sugars present in the tobacco plants. The induction of PR protein transcripts resulted in an accumulation of corresponding proteins. Moreover, the complete set of acidic PR-proteins induced by potato virus Y was also present in the sugar-accumulating transgenic plants. The induction of PR-proteins might be a generál response to the osmotic stress in tobacco plants.
Our experiment was carried out in order to explore effects of plant growth regulators (PGR; thidiazuron, paclobutrazol, and ascorbic acid) on physiological traits of wheat genotypes under water surplus and deficit conditions. Study revealed that relative water content, membrane stability index, chlorophyll content, photosynthetic rate (PN), and maximal quantum yield of PSII improved with PGRs application across the genotypes both under irrigation and water stress. The response of HD 2733 genotype was more positive toward PGRs treatment as compared to other genotypes under water stress. Higher PN and chlorophyll contents were observed in HD 2987 followed by C 306 genotype under water-stress conditions. Moreover, Rubisco small subunit (SSU) expression was lower in wheat genotypes under water stress as compared to irrigated conditions. Application of PGRs led to upregulation of SSU under water stress, while no significant change was found in Rubisco level and activity under irrigated condition in dependence on PGRs treatments. Yield-related traits showed also significant reduction under water-stress conditions, while application of PGRs enhanced the yield and its components. Results indicated that the PGRs exhibited a positive interaction and synergetic effect on water stressed wheat plants in terms of photosynthetic machinery and yield., S. K. Dwivedi, A. Arora, V. P. Singh, G. P. Singh., and Obsahuje bibliografii
The basics of the laser driven inertial fusion are explained. The meaning of scaling laws governing both the direct and indirect drive is illustrated in the context of the world largest laser projects NIF (USA) and LMJ (France) aiming at igniting thermonuclear targets. Demands on power station grade laser drivers are given in the light of arrival of YAG nanoceramics as a future laser material for high power, high repetition rate pulsed laser system. Tentative predictions are made for the future of major EU laser projects HiPER and ELI., Karel Rohlena., and Obsahuje bibliografii
An ICR outbred suckling mouse model of cryptosporidiosis was used to explain some of the variability associated with experimental Cryptosporidium parvum infections in neonate mice. Fourty four groups of 12 mice each, ranging in age from 4-12 days, each received 1.0 x 104 CsCl purified oocysts per os in 5 pm PBS. At 6 days post-inoculation (PI), mice were killed by C02 overdose and individually weighed. Intestines were then homogenized and oocysts were quantified by hemacytometer. Results revealed that both age and weight have pronounced effects on numbers of oocysts produced in vivo, with larger and older mice producing higher numbers of parasites. Mice 8-9 days of age at the time of inoculation displayed the least amount of weight dependent variability, produced the highest numbers of oocysts, and were judged to be superior over other ages for pharmaceutical screening. Significant reductions in numbers of oocysts occurred in mice inoculated at 10 days of age, and only a few oocysts were found in mice inoculated at 11-12 days of age. These studies suggest that at least some data on Cryptosporidium generated from suckling mouse studies to date are probably unreliable and should be viewed skeptically.
Infections of Unicauda clavicauda (Kudo, 1920) Davis, 1944 (Myxozoa) are described from Notropis hudsonius (Clinton) in Montana. Plasmodia form beneath scales of the body and produced spores within a loosely-defined matrix. Fixed spores are oval in front view, 11-14 pm long and 9-10.5 pm wide, and contain a posterior appendage that is up to 26 pm long. The polar capsules are 4-6 pm long and 2.5-4 pm wide. The study represents the first report of U. clavicauda since the original species description and a new host and geographical record. The taxonomic history of Unicauda Davis, 1944 is summarised and it is concluded the following 10 species are valid members of the genus: U. aristichthydis Zhao et Ma, 1995, U. brachyura (Ward, 1919), U. caudatus (Gogebashvili, 1965), U clavicauda, U. crassicauda (Kudo, 1934), U. lumae Rahemo, 1976, U. macrura (Gurley, 1893), U. magna Minchew, 1981, U. pelteobagrus Ma, 1998, and U. wuhanensis Xiao et Chen, 1993. All of these species have circular, subcircular, or oval spores in frontal view and all parasitise fish of the superorder Ostariophysi. As a group they are known from temperate freshwater locations in North America, Europe and Asia. A list of 16 species described or transferred to Unicauda at one time or another, but not recognised as members of the genus in the present study, is provided.