To investigate how excess excitation energy is dissipated in a ribulose-1,5-bisphospate carboxylase/oxygenase activase antisense transgenic rice with net photosynthetic rate (PN) half of that of wild type parent, we measured the response curve of PN to intercellular CO2 concentration (Ci), electron transport rate (ETR), quantum yield of open photosystem 2 (PS2) reaction centres under irradiation (Fv'/Fm'), efficiency of total PS2 centres (ΦPS2), photochemical (qP) and non-photochemical quenching (NPQ), post-irradiation transient increase in chlorophyll (Chl) fluorescence (PITICF), and P700+ re-reduction. Carboxylation efficiency dependence on Ci, ETR at saturation irradiance, and Fv'/Fm', ΦPS2, and qP under the irradiation were significantly lower in the mutant. However, NPQ, energy-dependent quenching (qE), PITICF, and P700+ re-reduction were significantly higher in the mutant. Hence the mutant down-regulates linear ETR and stimulates cyclic electron flow around PS1, which may generate the ΔpH to support NPQ and qE for dissipation of excess excitation energy. and S.-H. Jin ... [et al.].
The structure, expression and function of the transient receptor potential vanilloid 1 (TRPV1) receptor were intensively studied since the cloning in 1997 and TRPV1 receptors are now considered to act as transducers and molecular integrators of nociceptive stimuli in the periphery. In contrast, spinal TRPV1 receptors were studied less extensively and their role in pain modulation is still not fully understood. This short review is a follow up on our previous summary in this area ( Spicarova and Palecek 2008). The aim was to review preferentially the most recent findings concerning the role of the spinal TRPV1 receptors, published within the last five years. The update is given on the expression and function of the spinal TRPV1 receptors, their activation by endogenous agonists, interaction between the endocannabinoid and endovanillod system and possible role of the spinal TRPV1 receptors in pathological pain states. There is now mounting evidence that TRPV1 receptors may be an important element in modulation of nociceptive information at the spinal cord level and represent an interesting target for analgesic therapy., D. Spicarova, V. Nerandzic, J. Palecek., and Obsahuje bibliografii a bibliografické odkazy
Clusia is a widely distributed neotropical genus with 321 currently described species. This remarkable genus is the only one known to contain trees sensu stricto with CAM photosynthesis. To survey the occurrence of CAM in Clusia species from Colombia, we determined the leaf stable carbon isotope composition (δ13C) of 568 specimens from 114 species deposited in 12 Colombian herbaria. In the vast majority of specimens, δ13C values indicated that C3 photosynthesis was the principal contributor to carbon gain. δ13C values typical of strong CAM (less negative than -20‰) were observed in only five species, in four of them for the first time. All samples with CAM-type isotopic signatures were collected below 1,000 m a.s.l., whereas species with predominantly C3 occurred from sea level to 3,500 m a.s.l. Together with information already available in the literature, we conclude that CAM is present in 22% (35/156) of the species of Clusia investigated thus far.
Polarografická metoda umožňuje studium řady fyzikálněchemických problémů. Jsou uvedeny příklady z oblasti výzkumu struktury fázového rozhraní elektroda/roztok, adsorpce na povrchu elektrody, elektrochemického fotoefektu, fázových přechodů povrchových filmů, přenosu elektronu na molekulární vzdálenosti a oscilačních elektrochemických systémů., Polarography is a suitable method for solving numerous problems of physical chemistry. Examples from the following fields are given: structure of electrode/solution interfaces, adsorption on electrode surface, electrochemical photo-effect, phase transition of surface films, electron transfer over molecular distances, and electrochemical oscillating systems., Lubomír Pospíšil., and Obsahuje bibliografii
Pozměňování či falzifikace psaných textů jsou bezesporu staré jako sám vynález písma. Důvody pro takové jednání byly různé, nicméně skutečné stáří, respektive autenticita, daného rukopisu mají velký dopad na jeho význam, ať již pro historii, nebo - v případě současných rukopisů - z hlediska právního. U některých historických rukopisů je otázka jejich datování řešena s použitím spektroskopických technik, jejichž hlavní výhodou je nedestruktivnost nebo minimální invazivnost, neohrožující samu existenci zkoumaného dokumentu. V článku jsou zmíněny nejčastější spektroskopické metody používané k těmto účelům, včetně příkladů konkrétních studovaných rukopisů., The alteration or falsification of written texts is undoubtedly old as invention of scripture itself. The reasons for such behaviour are different, but the actual age or authenticity of the manuscript had a great impact on its signification, whether for history or, in the case of contemporary manuscripts, from a legal point of view. For historical manuscripts, the question of their dating is solved using spectroscopic techniques whose main advantage is non-destructiveness or minimal invasiveness, not endangering the very existence of the document under study. In the article the most frequent spectroscopic methods used for these purposes are mentioned and examples of particular studied manuscripts are given., Karel Nesměrák., and Obsahuje bibliografické odkazy