The kinetics of bacteriochlorophyll fluorescence in intact cells of the purple nonsulfur bacterium Rhodobacter sphaeroides were measured under continuous and pulsed actinic laser diode (808 nm wavelength and maximum 2 W light power) illumination on the micro- and millisecond timescale. The fluorescence induction curve was interpreted in terms of a combination of photochemical and triplet fluorescence quenchers and was demonstrated to be a reflection of redox changes and electron carrier dynamics. By adjustment of the conditions of single and multiple turnovers of the reaction center, we obtained 11 ms-1 and 120 μs-1 for the rate constants of cytochrome c23+ detachment and cyclic electron flow, respectively. The effects of cytochrome c2 deletion and chemical treatments of the bacteria and the advantages of the fluorescence induction study on the operation of the electron transport chain in vivo were discussed., G. Sipka, M. Kis, J. L. Smart, P. Maróti., and Obsahuje bibliografické odkazy
The aim of this study was to investigate whether haemocytes of Galleria mellonella (Lepidoptera: Pyralidae) larvae produce reactive oxygen species (ROS) like human blood phagocytes. The production of ROS was measured first using luminol-enhanced chemiluminescence of un-stimulated and stimulated (four activators with different modes of action) haemolymph or isolated haemocytes. However, spontaneous and activated production of ROS remained at the background level. In subsequent experiments an ultrasensitive fluorescence method using Amplex Red reagent to detect hydrogen peroxide (H2O2) was used. After optimization, Amplex Red was successfully used for determining H2O2 production by both un-stimulated and stimulated haemocytes. To determine the affect of pH and ions on the measurement, several diluent solutions were tested. This revealed that Ca2+ and Mg2+ ions are less important for the reaction in insect than mammalian cells. Among the activators tested, phorbol myristate acetate (PMA) and calcium ionophore (Ca-I) had the best stimulatory effect on insect samples, while opsonised zymosan particles (OZP) was the best activator for human phagocytes. In conclusion, the haemocytes of G. mellonella produce H2O2 as an important innate immunity factor, but under different conditions and in different amounts, which probably results in them being less effective in killing microbes than human phagocytes. and Ondřej Vašíček, Ivana Papežíková, Pavel Hyršl.
Photosynthetic organs are often characterized by anthocyanins being accumulated either in the epidermal or in the mesophyll cells making these tissues to turn reddish-brown in colour. It has been hypothesized that these pigments protect underlying chloroplasts from light-stress because they absorb photons of the photosynthetically active waveband. However, the photoprotective role of anthocyanins has not been undoubtedly shown on a broad range of species. In this study, green and anthocyanic areas of leaves of Pelargonium × hortorum, the latter possessing variable levels of anthocyanins, were compared using pigment analysis and pulse amplitude modulated in vivo chlorophyll (Chl) fluorescence. Quenching analysis of the induction and dark relaxation curves of slow Chl fluorescence kinetics showed that at photoinhibitory conditions [by applying above-saturation light intensity of 1,600 μmol(quantum) m-2 s-1 white light at low (4°C) temperature], anthocyanic areas were at least equally sensitive to photoinhibition as green leaf areas. In fact, the level of photoinhibition tended to be proportional to the level of anthocyanin accumulation suggesting that this characteristic was indicative of the photoinhibitory risk. The results of the present study clearly show that anthocyanins in leaf areas of Pelargonium do not afford a photoprotective advantage., G. Liakopoulos, I. Spanorigas., and Obsahuje bibliografii
Brassinosteroids (BRs), an important class of plant steroidal hormones, play a significant role in the amelioration of various biotic and abiotic stresses. 24-epibrassinolide (EBR), an active brassinosteroid, was applied exogenously in different concentrations to characterize a role of BRs in tolerance of melon (Cucumis melo L.) to high temperature (HT) stress and to investigate photosynthetic performance of HT-stressed, Honglvzaocui (HT-tolerant) and Baiyuxiang (HTsensitive), melon variety. Under HT, Honglvzaocui showed higher biomass accumulation and a lower index of heat injury compared with the Baiyuxiang. The exogenous application of 1.0 mg L-1 EBR, the most effective concentration, alleviated dramatically the growth suppression caused by HT in both ecotypes. Similarly, EBR pretreatment of HTstressed plants attenuated the decrease in relative chlorophyll content, net photosynthetic rate, stomatal conductance, stomatal limitation, and water-use efficiency (WUE), as well as the maximal quantum yield of PSII photochemistry (Fv/Fm), the efficiency of excitation capture of open PSII center, the effective quantum yield of PSII photochemistry (ΦPSII), photochemical quenching coefficient, and the photon activity distribution coefficients of PSI (α). EBR pretreatment further inhibited the increase in intracellular CO2 concentration, leaf transpiration rate, minimal fluorescence of dark-adapted state, nonphotochemical quenching, thermal dissipation, and photon activity distribution coefficients of PSII. Results obtained here demonstrated that EBR could alleviate the detrimental effects of HT on the plant growth by improving photosynthesis in leaves, mainly reflected as up-regulation of photosynthetic pigment contents and photochemical activity associated with PSI. and Y. P. Zhang ... [et al.].
In the past decade, utilization of nanostructured materials has increased intensively in a wide range of applications. Titanium dioxide nanoparticles (TiO2 NPs), for instance, can be applied for the inactivation of various pathogens through photo-induced generation of reactive oxygen species. Although TiO2 NPs with high antimicrobial activity are of great importance, in practice, their phytotoxic effects have not yet been fully clarified. In this study, we investigated the potential phytotoxicity of TiO2 NPs on grapevine (Vitis vinifera L.) under field conditions. After foliar exposure, two particularly stress-sensitive parameters, photosynthetic function and the flavonol profile, were examined. Micro- and macroelement composition of the leaves was also studied by ICP-AES measurements. We found that TiO2 NPs significantly decreased the net CO2 assimilation and increased stomatal conductance, indicating metabolic (nonstomatal) inhibition of the photosynthesis. The lower electron transport rate and lower nonphotochemical quenching in treated leaves are indicative of diminished photoprotective processes., P. Teszlák, M. Kocsis, A. Scarpellini, G. Jakab, L. Kőrösi., and Obsahuje bibliografii
Despite the elimination of the original forest and frequent cultivation using slash and burn, a large spread in leaf δ13C was recorded in weeds, crops, and bush fallow species, reflecting a forest environment rather than a broken canopy or open environment., A. De Rouw, J .F. Maxwell, C. Girardin., and Obsahuje bibliografii
Forenzní entomologie představuje oblast aplikované biologie, která propojuje přírodní vědy a právní systém. Tento obor lze rozdělit na tři hlavní oblasti: problematiku škůdců potravin a zemědělských produktů, oblast parazitů lidí a zvířat (zejména otázku myiáz) a patrně nejznámější a nejčastěji využívanou oblast stanovení doby smrti člověka, resp. post mortem intervalu (PMI). Jeho základem je přirozený proces degradace mrtvých obratlovců v přírodě, kdy během sukcese tělo postupně kolonizují mouchy, brouci a další bezobratlí. Znalost těchto procesů nám dává možnost určit dobu kolonizace, a tím i PMI s přesností na den i několik týdnů po smrti člověka. Avšak pole působnosti forenzní entomologie je natolik široké, že článek přináší pouze malé nahlédnutí do základů tohoto multidisciplinárního oboru. Proto není překvapením, že přes všechny naše dosavadní znalosti a poznatky forenzní entomologie, každý den přináší stále nové otázky a odpovědi., Forensic entomology is a field of applied biology in which natural science and the judicial system interact. It can be divided into three main areas: the issue of pests, the field of human and animal parasites, mainly a phenomenon called myiasis, and probably the best known and most frequently used area of estimating the period of time since human death or post mortem interval (PMI). It is based on the natural process of degradation of animal cadavers and human corpses when during the process of succession flies, beetles and other invertebrates subsequently colonize a corpse. Good knowledge of the processes allows us to determine the time of colonization as well as PMI within a day even several weeks after the human death. However, the scope of forensic entomology is so wide that this article provides only a small insight into the foundations of this multidisciplinary field. Therefore it is not surprising that despite all of our current knowledge forensic entomology presents new questions and answers every day., and Hana Šuláková.
The aim of the present study was to find groups of moths suitable for estimating changes in the abundance and richness of local and regional biodiversity in a temperate forest. We captured macro-moths from May to October over a 5-year period (2005–2009) at various sites in Mt. Jirisan National Park (JNP) in southern Korea. Six taxa were selected based on a strong correlation between the number of species in these taxa and total number of species of large moths: Ennominae (Enn), Arctiinae (Arc), Hermininae (Her), Notodontidae (Not), Drepanidae (Dre) and Ophiderinae (Oph). Of these, combinations of four groups were found to have the best predictive capability. We determined whether these indicator groups could be used to reveal mean differences in species abundance according to spatial (forest type, altitude) and temporal variables (monsoon season) since moth composition and abundances were closely related with these variables. The mean differences in the groups of moths in the two types of forest (Arc, Dre, Enn, Not), two altitudes (Dre, Enn, Her, Oph) and two seasons (Dre, Enn, Oph) were significant. Overall, it was revealed that a set of four groups, including two taxa (Dre and Enn), could be used to show differences in local and regional biodiversity of moths in southern Korean temperate forest., Jeong-Seop An, Sei-Woon Choi., and Obsahuje seznam literatury
Dnešní terestrické ekosystémy jsou do značné míry produktem koevoluce rostlin a hmyzu, který představuje vůbec nejpočetnější a nejrozmanitější skupinu živočichů. Počátky tohoto vzájemného působení lze vysledovat stovky milionů let do minulosti, přičemž postupně docházelo k nárůstu jeho komplexity. Nejčastějšími doklady těchto složitých vztahů jsou fosilizované listy nebo jejich otisky, vykazující často specifické i nespecifické poškození, jako jsou miny nebo hálky, stopy po ovipozici, popřípadě nejrůznější typy okusů. Kvalitativní a kvantitativní analýza těchto stop má velký význam při studiu evolučních procesů v rámci výše uvedených skupin organismů. Detekované změny v dynamice trofických vztahů mezi hmyzem a jeho rostlinnými hostiteli pomáhají zpřesnit představu o vlivu měnícího se prostředí na okolní biotu, jakož i poskytují vodítko pro stanovování průběhu klimatických změn v čase., Contemporary terrestrial ecosystems are largely a product of the coevolution of plants and insects, which are the most prevalent and diverse group of animals. The origin of these interactions can be traced hundreds of millions of years back followed by a gradual increase in their complexity. The most common evidence of these complex relationships is represented by the fossilized leaves, often having specific and non-specific damage such as the mines, galls, traces of oviposition, or various types of feeding. Qualitative and quantitative analyses of these ichnofossils are of great importance with regard to the study of the evolutionary processes occurring among these groups of organisms. The detected changes in the dynamics of trophic relationships between insects and their host plants help to clarify ideas regarding the impact on the developing environment and organisms, and provide evidence for the recognition of trends in climate changes in the past., and Stanislav Knor, Jakub Prokop.