Kudlanka nábožná (Mantis religiosa) je příklad teplomilného druhu, který v posledních letech začal expandovat i do severnějších oblastí Evropy. Na základě studia mitochondriálních markerů se ukázalo, že v rámci Evropy kudlanky náleží do tří odlišných genetických linií. Tyto linie (západoevropská, středoevropská a východoevropská) se postupně po poslední době ledové šířily na sever z různých glaciálních refugií. Tuto teorii také podporují paleoklimatická data a distribuční modely možného šíření kudlanek po poslední době ledové., The Praying Mantis (Mantis religiosa) is an example of a thermophilic species, which has recently been expanding northwards across Europe. Based on the study of mitochondrial genes, it has been shown, that the European M. religiosa belong to three different genetic lineages (West-, Central- and East-European). These lineages have been gradually spreading northwards from different glacial refugias after the last glacial period. This theory has also been supported using paleoclimatic data and distribution models of the potential spread of M. religiosa after the last glacial period., and Jakub Vitáček, Petr Janšta.
Species–area relationships and nestedness patterns were studied in three groups of small terrestrial vertebrates (mammals, reptiles, amphibians) on 14 landbridge islands of the eastern Adriatic. Islands ranged in surface area between 15 and 410 km2 and contained from eight to 36 species from a total species pool of 48. Reptiles were the most species rich group (S = 28), and had more species than mammals (S = 13) and amphibians (S = 7) combined. Island surface area predicted species richness best in reptiles (r2 = 0.79) and most poorly in amphibians (r2 = 0.52). Mammals showed a significantly lower slope of the species–area curve than amphibians and reptiles, and thus accumulated species counts with increase in area at the lowest rate. Nestedness patterns in all groups were significantly more organised than expected by chance. Amphibian nested structure points to extinction dominated and well insularised populations with no subsequent recolonisations. Frequent unexpected presences and absences in the nestedness patterns of mammals and reptiles suggest complex biogeographic histories for these two groups, with several factors putatively in operation: heterogeneity in habitats and the original source fauna, post- isolation immigrations and differential extinction rate due to human-caused habitat degradation.
Noble gases are known for their inertness. They do not react chemically with any element at normal temperature and pressure. Through that, some of them are known to be biologically active by their sedative, hypnotic and analgesic properties. Common inhalation anesthetics are characterized by some disadvantages (toxicity, decreased cardiac output, etc). Inhalation of xenon introduces anesthesia and has none of the above disadvantages, hence xenon seems to be the anesthetic gas of the future (with just one disadvantage - its cost). It is known that argon has similar anesthetic properties (under hyperbaric conditions), which is much cheaper and easily accessible. The question is if this could be used in clinical practice, in anesthesia of patients who undergo treatment in the hyperbaric chamber. Xenon was found to be organ-protective. Recent animal experiments indicated that xenon decreases infarction size after ischemic attack on brain or heart. The goal of our study is to check if hyperbaric argon has properties similar to those of xenon., J. Růžička, J. Beneš, L. Bolek, V. Markvartová., and Obsahuje bibliografii
Selenium is a trace element that is essential for living organism. Its beneficial effect is, however, expressed in a very narrow dosage range: the high and low doses of selenium are connected with pathological manifestations. The toxicity depends on the chemical form of selenium, state of organism, interactions with heavy metals and on the stage of ontogenetic development. Whereas one dose of sodium selenite (20 μmol/kg b.w.) is lethal in adult rats, suckling rats are entirely resistant. However, within one week after administration of the same dose, cataract of eye lens developed. The highest incidence of cataract was observed in 10-day-old animals and it decreased until day 20. From postnatal day 20 to day 40 the rats were resistant to both the lethal and cataractogenic effects of selenium. The incidence of cataract may be suppressed by premature weaning, lower hydration of suckling, change of water soluble/water insoluble lens protein ratio, thyroxine treatment, and by interaction with mercury. By means of its oxidative and reduction properties, selenium is involved in the maintenance of the cell redox homeostasis. Typical example is its possible cardioprotective effect: selenium decreased number of arrhythmias, reduced infarct size and improved the contractile recovery after ischemia/reperfusion injury. Selenium supplementation may thus increase cardiac tolerance to ischemic damage., I. Ošťádalová., and Obsahuje seznam literatury
A new generator of two successive shock waves focused to a common focal point has been developed. Cylindrical pressure waves created by multichannel electrical discharges on two cylindrical composite anodes are focused by a metallic parabolic reflector - cathode, and near the focus they are transformed to strong shock waves. Schlieren photos of the focal region have demonstrated that mutual interaction of the two waves results in generation of a large number of secondary short-wavelength shocks. Interaction of the focused shockwaves with liver tissues and cancer cell suspensions was investigated. Localized injury of rabbit liver induced by the shock waves was demonstrated by magnetic resonance imaging. Histological analysis of liver samples taken from the injured region revealed that the transition between the injured and the healthy tissues is sharp. Suspension of melanoma B16 cells was exposed and the number of the surviving cells rapidly decreased with increasing number of shocks and only 8 % of cells survived 350 shocks. Photographs of cells demonstrate that even small number of shocks results in perforation of cell membranes., J. Beneš, P. Šunka, J. Králová, J. Kašpar, P. Poučková., and Obsahuje bibliografii
The parallel course of the excretion rates of bromide and sodium ions was demonstrated in adult male and female rats administered simultaneously with potassium 82Br-bromide and 24Na-sodium chloride. The animals were exposed to various intakes of sodium ions accompanied with five different anions: Br-, Cl-, HCO3-, ClO4-, and SCN-. Regardless of the anion accompanying the sodium ion, the excretion rates of 82Br- and 24Na+ ions were proportional to the magnitude of sodium intake in the animals. Hence, we have proved our hypothesis that the biological half-life of bromide depends on the magnitude of sodium intake rather than on the intake of chloride.