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51.
Elter A Hartel A Sieben C Hertel B Fischer-Schliebs E Lüttge U Moroni A Thiel G 《The Journal of biological chemistry》2007,282(12):8786-8792
The genome of Arabidopsis thaliana contains unusual members of the glutathione S-transferase (GST) superfamily with a cysteine in place of a serine at the active site. Four of these genes (at-dhar 1-4) have an appreciable homology to intracellular Cl- channels (CLICs) from vertebrates and invertebrates. Transient expression of AtDHAR1 as wild type protein or as a chimera with GFP in mammalian HEK293 or Chinese hamster ovary cells generated a distinct inward rectifying conductance with a characteristic biphasic kinetics but no apparent ion selectivity. Analysis of the subcellular localization of AtDHRA1::GFP showed that the bulk of the protein was located as soluble form in the cytoplasm; however, an appreciable fraction of it could also be found in association with the non-soluble microsomal fraction. These data suggest that plant members of the GST superfamily have similar to those from animals multiple functions. The increase of ion conductance by AtDHAR1 is better explained by a CLIC-like channel activity than by a modification of endogenous channel proteins. 相似文献
52.
In this methods paper, one-dimensional moisture penetration into thin films of sugar glass exposed to different relative humidity
was measured by use of FT-near infrared microspectroscopy working in a spectrum range of wavelength from 1.35 to 2.50 μm.
The peak height ratio of characteristic peaks for H—OH (primarily water) and O—H (primarily sugar) bands, respectively, were
highly correlated to moisture content for both sucrose and lactose systems and were used for calibration of moisture content.
Moisture content along one-dimensional locations was accurately measured using microscopic mapping. Sorption penetration profiles
of moisture content vs. penetration depth were obtained. Depending on the sorption time and storage conditions, moisture penetration
profiles typically showed a fairly sharp boundary between intact glass in the interior and a high moisture content surface
layer, which slowly moved into the sample interior over time. Crystallization was observed to occur at the surface under certain
conditions when insufficient inhibitors were present. In these cases, a moisture peak was seen to penetrate into the glass.
Microspectroscopic mapping proved to be an excellent technique for studying moisture penetration behavior and kinetics, providing
quantitative data for future diffusion modeling.
Support source: NIRCGP grant from USDA. 相似文献
53.
Laura M. E. Sutcliffe Pter Batry Urs Kormann Andrs Bldi Lynn V. Dicks Irina Herzon David Kleijn Piotr Tryjanowski Iva Apostolova Raphaël Arlettaz Ainars Aunins Stphanie Aviron Ligita Baleentien Christina Fischer Lubos Halada Tibor Hartel Aveliina Helm Iordan Hristov Sven D. Jelaska Mitja Kaligari
Johannes Kamp Sebastian Klimek Pille Koorberg Jarmila Kostiukov Anik Kovcs‐Hostynszki Tobias Kuemmerle Christoph Leuschner Regina Lindborg Jacqueline Loos Simona Maccherini Riho Marja Orsolya Mth Inge Paulini Vnia Proena Jos Rey‐Benayas F. Xavier Sans Charlotte Seifert Jarosaw Stalenga Johannes Timaeus Pter Trk Chris van Swaay Eneli Viik Teja Tscharntke 《Diversity & distributions》2015,21(6):722-730
A large proportion of European biodiversity today depends on habitat provided by low‐intensity farming practices, yet this resource is declining as European agriculture intensifies. Within the European Union, particularly the central and eastern new member states have retained relatively large areas of species‐rich farmland, but despite increased investment in nature conservation here in recent years, farmland biodiversity trends appear to be worsening. Although the high biodiversity value of Central and Eastern European farmland has long been reported, the amount of research in the international literature focused on farmland biodiversity in this region remains comparatively tiny, and measures within the EU Common Agricultural Policy are relatively poorly adapted to support it. In this opinion study, we argue that, 10 years after the accession of the first eastern EU new member states, the continued under‐representation of the low‐intensity farmland in Central and Eastern Europe in the international literature and EU policy is impeding the development of sound, evidence‐based conservation interventions. The biodiversity benefits for Europe of existing low‐intensity farmland, particularly in the central and eastern states, should be harnessed before they are lost. Instead of waiting for species‐rich farmland to further decline, targeted research and monitoring to create locally appropriate conservation strategies for these habitats is needed now. 相似文献
54.
Lee R Nasonova E Hartel C Durante M Ritter S 《Radiation and environmental biophysics》2011,50(3):371-381
The relationship between heavy-ion-induced cell cycle delay and the time-course of aberrations in first-cycle metaphases or
prematurely condensed G2-cells (G2-PCC) was investigated. Lymphocytes of the same donor were irradiated with X-rays or various charged particles (carbon, iron,
xenon, and chromium) covering an LET range of 2–3,160 keV/μm. Chromosome aberrations were measured in samples collected at
48, 60, 72, and 84 h postirradiation. Linear-quadratic functions were fitted to the data, and the fit parameters α and β were
determined. At any sampling time, α values derived from G2-cells were higher than those from metaphases. The α value derived from metaphase analysis at 48 h increased with LET, reached
a maximum around 155 keV/μm, and decreased with a further rise in LET. At the later time-points, higher α values were estimated
for particles with LET > 30 keV/μm. Estimates of α values from G2-cells showed a similar LET dependence, yet the time-dependent increase was less pronounced. Altogether, our data demonstrate
that heavily damaged lymphocytes suffer a prolonged G2-arrest that is clearly LET dependent. For this very reason, the standard analysis of aberrations in metaphase cells 48 h
postirradiation will considerably underestimate the effectiveness of high-LET radiation. Scoring of aberrations in G2-PCC at 48 h as suggested by several authors will result in higher aberration yields. However, when particles with a very
high-LET value (LET > 150 keV/μm) are applied, still a fraction of multiple damaged cells escape detection by G2-analysis 48 h postirradiation. 相似文献
55.
Bruno Gomes Carla A Sousa Maria T Novo Ferdinando B Freitas Ricardo Alves Ana R Côrte-Real Patrícia Salgueiro Martin J Donnelly António PG Almeida João Pinto 《BMC evolutionary biology》2009,9(1):262-15
Background
Culex pipiens L. is the most widespread mosquito vector in temperate regions. This species consists of two forms, denoted molestus and pipiens, that exhibit important behavioural and physiological differences. The evolutionary relationships and taxonomic status of these forms remain unclear. In northern European latitudes molestus and pipiens populations occupy different habitats (underground vs. aboveground), a separation that most likely promotes genetic isolation between forms. However, the same does not hold in southern Europe where both forms occur aboveground in sympatry. In these southern habitats, the extent of hybridisation and its impact on the extent of genetic divergence between forms under sympatric conditions has not been clarified. For this purpose, we have used phenotypic and genetic data to characterise Cx. pipiens collected aboveground in Portugal. Our aims were to determine levels of genetic differentiation and the degree of hybridisation between forms occurring in sympatry, and to relate these with both evolutionary and epidemiological tenets of this biological group. 相似文献56.
57.
Styrofoam Cup-Membrane Assembly for Studying Microorganism-Root Interactions 总被引:1,自引:1,他引:0 下载免费PDF全文
An assembly consisting of Styrofoam cups with membranes of varying porosities was developed to study microorganism-root interactions. The assembly permitted uniform distribution of a bacterium in soil and was simple, easy to use, and disposable. In tests with the bacterium Pseudomonas solanacearum, little difference in P. solanacearum survival was observed in the rhizosphere or nonrhizosphere of tomato. 相似文献
58.
59.
Xanthophyll-cycle kinetics as well as the relationship between the xanthophyll de-epoxidation state and Stern-Volmer type nonphotochemical chlorophyll (Chl) fluorescence quenching (qN) were investigated in barley (Hordeum vulgare L.) leaves comprising a stepwise reduced antenna system. For this purpose plants of the wild type (WT) and the Chl b-less mutant chlorina 3613 were cultivated under either continuous (CL) or intermittent light (IML). Violaxanthin (V) availability varied from about 70% in the WT up to 97 to 98% in the mutant and IML-grown plants. In CL-grown mutant leaves, de-epoxidation rates were strongly accelerated compared to the WT. This is ascribed to a different accessibility of V to the de-epoxidase due to the existence of two V pools: one bound to light-harvesting Chl a/b-binding complexes (LHC) and the other one not bound. Epoxidation rates (k) were decreased with reduction in LHC protein contents: kWT > kmutant >> kIML plants. This supports the idea that the epoxidase activity resides on certain LHC proteins. Irrespective of huge zeaxanthin and antheraxanthin accumulation, the capacity to develop qN was reduced stepwise with antenna size. The qN level obtained in dithiothreitol-treated CL- and IML-grown plants was almost identical with that in untreated IML-grown plants. The findings provide evidence that structural changes within the LHC proteins, mediated by xanthophyll-cycle operation, render the basis for the development of a major proportion of qN. 相似文献
60.
A new deepsea monognathid species,Monognathus berteli, is described based on one specimen collected pelagically in the northwestern Indian Ocean at 1440–1018 meters of depth.
LikeM. taningi andM. bertini, it belongs to the short-skulled species-group and has very long pectoral fins, but differs from these species by several
meristic characters. The described specimen has a very long caudal filament (53% SL) which is not known from otherMonognathus. However, the fragile filament is not used as a diagnostic character since it could easily be broken. 相似文献