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61.
Blocking the QB‐binding site of photosystem II by tenuazonic acid,a non–host‐specific toxin of Alternaria alternata,activates singlet oxygen‐mediated and EXECUTER‐dependent signalling in Arabidopsis 下载免费PDF全文
SHIGUO CHEN CHANHONG KIM JE MIN LEE HYUN‐AH LEE ZHANGJUN FEI LIANGSHENG WANG KLAUS APEL 《Plant, cell & environment》2015,38(6):1069-1080
Necrotrophic fungal pathogens produce toxic compounds that induce cell death in infected plants. Often, the primary targets of these toxins and the way a plant responds to them are not known. In the present work, the effect of tenuazonic acid (TeA), a non–host‐specific toxin of Alternaria alternata, on Arabidopsis thaliana has been analysed. TeA blocks the QB‐binding site at the acceptor side of photosystem II (PSII). As a result, charge recombination at the reaction centre (RC) of PSII is expected to enhance the formation of the excited triplet state of the RC chlorophyll that promotes generation of singlet oxygen (1O2). 1O2 activates a signalling pathway that depends on the two EXECUTER (EX) proteins EX1 and EX2 and triggers a programmed cell death response. In seedlings treated with TeA at half‐inhibition concentration 1O2‐mediated and EX‐dependent signalling is activated as indicated by the rapid and transient up‐regulation of 1O2‐responsive genes in wild type, and its suppression in ex1/ex2 mutants. Lesion formation occurs when seedlings are exposed to higher concentrations of TeA for a longer period of time. Under these conditions, the programmed cell death response triggered by 1O2‐mediated and EX‐dependent signalling is superimposed by other events that also contribute to lesion formation. 相似文献
62.
Differences in single-copy nuclear-DNA sequences among 13 species of
passerine birds were measured using DNA-DNA hybridization. A matrix of
pairwise dissimilarity values (delta mode distances) was constructed from
analysis of fitted thermal dissociation curves. A least-squares method of
phylogenetic estimation was used to construct two topologies from the
distance matrix, one constraining branch lengths of sister taxa to be equal
and the other permitting such lengths to vary. These topologies were
identical in the pattern of branching of taxa, and the difference in their
sums of squares was not statistically significant, suggesting that rates of
DNA evolution in sister groups of nine- primaried oscines are equal. A
nonparametric test for nonrandom variation in distances of sister groups to
outgroup taxa revealed no statistically significant deviation from random
variation that would be expected as a result of measurement error. However,
the level of measurement error was such that rates of DNA evolution in
sister taxa could vary by as much as 10% without being detected with the
statistical methods used here.
相似文献
63.
脑电信号数据压缩及棘波识别的小波神经网络方法 总被引:1,自引:0,他引:1
本文在对小波神经网络及其算法研究的基础上,提出了一种对脑电信号压缩表达和痫样脑电棘波识别的新方法。实验结果显示,小波网络在大量压缩数据的同时,能够较好的恢复原有信号,另外,在脑电信号的时频谱等高线图上,得到了易于自动识别的棘波和棘慢复合波特征,说明此方法在电生理信号处理和时频分析方面有着光明的应用前景。 相似文献
64.
14-3-3 proteins double the number of outward-rectifying K+ channels available for activation in tomato cells 总被引:1,自引:0,他引:1
Booij PP Roberts MR Vogelzang SA Kraayenhof R De Boer AH 《The Plant journal : for cell and molecular biology》1999,20(6):673-683
Outward-rectifying K+ channels are modulated in response to environmental stimuli by a range of intracellular factors, such as cytoplasmic Ca2+, pH, kinases and phosphatases. Here we report that voltage-dependent outward-rectifying K+ channels in tomato cells are also targets for modulation by 14-3-3 proteins. In whole-cell patch-clamp experiments, recombinant 14-3-3 protein (tomato isoform TFT7) was introduced into tomato cell protoplasts via the patch pipette. As a result the steady-state outward K+ current increased twofold and this increase was not dependent upon the presence of cytoplasmic ATP. A phosphorylated peptide that contained a phosphorylated 14-3-3 target-binding motif (RSTS*TP), derived from nitrate reductase, blocked the effect of 14-3-3, thus showing the specific nature of 14-3-3 action. Kinetic parameters of the conductance, like (de)activation kinetics, voltage dependence of gating and activation potential, were not significantly different between control and 14-3-3 infused cells. Analysis of single-channel activity and whole-cell noise indicated that the single-channel conductance was not affected by 14-3-3 infusion. We conclude that 14-3-3 proteins recruit 'sleepy' channels into a voltage-activatable state. The molecular mechanism underlying the 1 : 1 ratio of constitutively active and 14-3-3 recruited channels is discussed in the light of known functions of 14-3-3 dimers. 相似文献
65.
66.
Hanka Venselaar Tim AH te Beek Remko KP Kuipers Maarten L Hekkelman Gert Vriend 《BMC bioinformatics》2010,11(1):548
Background
Many newly detected point mutations are located in protein-coding regions of the human genome. Knowledge of their effects on the protein's 3D structure provides insight into the protein's mechanism, can aid the design of further experiments, and eventually can lead to the development of new medicines and diagnostic tools. 相似文献67.
Timm Konold Yoon Hee Lee Michael J Stack Claire Horrocks Robert B Green Melanie Chaplin Marion M Simmons Steve AC Hawkins Richard Lockey John Spiropoulos John W Wilesmith Gerald AH Wells 《BMC veterinary research》2006,2(1):1-20
Background
Given the theoretical proposal that bovine spongiform encephalopathy (BSE) could have originated from sheep scrapie, this study investigated the pathogenicity for cattle, by intracerebral (i.c.) inoculation, of two pools of scrapie agents sourced in Great Britain before and during the BSE epidemic. Two groups of ten cattle were each inoculated with pools of brain material from sheep scrapie cases collected prior to 1975 and after 1990. Control groups comprised five cattle inoculated with sheep brain free from scrapie, five cattle inoculated with saline, and for comparison with BSE, naturally infected cattle and cattle i.c. inoculated with BSE brainstem homogenate from a parallel study. Phenotypic characterisation of the disease forms transmitted to cattle was conducted by morphological, immunohistochemical, biochemical and biological methods.Results
Disease occurred in 16 cattle, nine inoculated with the pre-1975 inoculum and seven inoculated with the post-1990 inoculum, with four cattle still alive at 83 months post challenge (as at June 2006). The different inocula produced predominantly two different disease phenotypes as determined by histopathological, immunohistochemical and Western immunoblotting methods and biological characterisation on transmission to mice, neither of which was identical to BSE. Whilst the disease presentation was uniform in all scrapie-affected cattle of the pre-1975 group, the post-1990 inoculum produced a more variable disease, with two animals sharing immunohistochemical and molecular profile characteristics with animals in the pre-1975 group.Conclusion
The study has demonstrated that cattle inoculated with different pooled scrapie sources can develop different prion disease phenotypes, which were not consistent with the phenotype of BSE of cattle and whose isolates did not have the strain typing characteristics of the BSE agent on transmission to mice. 相似文献68.
Studies of the influence of fish aquaculture on benthic freshwater nematode assemblages are scarce, but could provide a way of gauging environmental effects. The abundance and diversity of nematode assemblages in response to Oreochromis niloticus aquaculture were investigated in Kafr El-Sheikh Governorate, Egypt, from July to November 2014 under conditions of irrigation (reference), fish farm pond with high Tilapia density, and fish farm pond effluent canal without fish. The nematode genera Adoncholaimus, Punctodora, Labronema, Oncholaimus and Odontolaimus were present at all sites. Environmental factors were not related to nematode distribution patterns. Tilapia predation and/or disturbance may explain reduced nematode abundance, especially of the largest genera, Adoncholaimus, Punctodora and Labronema at the fish farm site. The absence of fish from the drainage site allowed intergeneric nematode competitive exclusion, benefitting the largest nematodes and reducing diversity indices. 相似文献
69.
RD Calixto R Verlengia AH Crisp TB Carvalho MD Crepaldi AA Pereira AK Yamada GR da Mota CR Lopes 《Biology of sport / Institute of Sport》2014,31(4):289-294
This study aimed to compare the effects of different velocities of eccentric muscle actions on acute blood lactate and serum growth hormone (GH) concentrations following free weight bench press exercises performed by resistance-trained men. Sixteen healthy men were divided into two groups: slow eccentric velocity (SEV; n = 8) and fast eccentric velocity (FEV; n = 8). Both groups performed four sets of eight eccentric repetitions at an intensity of 70% of their one repetition maximum eccentric (1RMecc) test, with 2-minute rest intervals between sets. The eccentric velocity was controlled to 3 seconds per range of motion for SEV and 0.5 seconds for the FEV group. There was a significant difference (P < 0.001) in the kinetics of blood lactate removal (at 3, 6, 9, 15, and 20 min) and higher mean values for peak blood lactate (P = 0.001) for the SEV group (9.1 ± 0.5 mM) compared to the FEV group (6.1 ± 0.4 mM). Additionally, serum GH concentrations were significantly higher (P < 0.001) at 15 minutes after bench press exercise in the SEV group (1.7 ± 0.6 ng · mL−1) relative to the FEV group (0.1 ± 0.0 ng · mL−1). In conclusion, the velocity of eccentric muscle action influences acute responses following bench press exercises performed by resistance-trained men using a slow velocity resulting in a greater metabolic stress and hormone response. 相似文献
70.
Femke AH van der Linden Jolijn J Kragt Margarethe van Bon Martin Klein Alan J Thompson Henk M van der Ploeg Chris H Polman Bernard MJ Uitdehaag 《BMC neurology》2008,8(1):2