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81.
Transgenicwheat plants (variety Frisal) constitutively expressing a number of potentialantifungal proteins alone or in combinations were generated and tested forincreased resistance to Blumeria graminis f.sp. tritici(powdery mildew) in a detached leaf infection assay. The most significativerateof protection was obtained with an apoplastic ribosome-inactivation proteinfrombarley seed. Apoplastic Barnase was less efficient and individual plant linesharbouring a barley seed chitinase and -1,3-glucanase showed linespecificphenotypes from increased resistance to increased susceptibility. Combinationbycrossing of three barley seed proteins did not lead to significant improvementof protection.  相似文献   
82.
The effects of experimental parameters including soil type, curing duration, inoculum size, and biomass and nutrients concentration on soil strengthening due to calcite precipitation by Sporosarcina pasteurii PTCC 1645 were investigated. The laboratory-scale mixing experiments on remolded samples were designed by the Taguchi method. Soil type proved to be the most incorporating factor, followed by curing time and nutrient concentration. The main effect and the interactions of the parameters were presented and the optimal conditions were obtained. This suggests the importance of local conditions including soil type on any future large-scale, in situ application.  相似文献   
83.
Ubiquinone (UQ) formation in BY-2 tobacco cells was especially promoted by a high concentration of 2,4-D. 2,4,5-T, MCP and NAA also promoted UQ formation in these cells. The UQ content in the cells cultured at high concentrations of 2,4-D was higher than that of controls throughout the culture period. The addition of 2,4-D at an early period in cell growth was very effective in promoting UQ formation, but addition at the stationary phase was ineffective. Cell growth was improved by adding phosphate to the medium but UQ content was decreased. UQ content decreased slowly during subculturing, whereas cell growth recovered gradually.  相似文献   
84.
A newly developed modulation fluorometer is described which operates with 1 sec light pulses from a light-emitting diode (LED) at 100 KHz. Special amplification circuits assure a highly selective recording of pulse fluorescence signals against a vast background of non-modulated light. The system tolerates ratios of up to 1:107 between measuring light and actinic light. Thus it is possible to measure the dark fluorescence yield and record the kinetics of light-induced changes. A high time resolution allows the recording of the rapid relaxation kinetic following a saturating single turnover flash. Examples of system performance are given. It is shown that following a flash the reoxidation kinetics of photosystem II acceptors are slowed down not only by the inhibitor DCMU, but by a number of other treatments as well. From a light intensity dependency of the induction kinetics the existence of two saturated intermediate levels (I1 and I2) is apparent, which indicates the removal of three distinct types of fluorescence quenching in the overall fluorescence rise from F0 to Fmax.Abbreviations QA and QB consecutive electron acceptors of photosystem II - PS II photosystem II - P 680 reaction center chlorophyll of photosystem II - F0 minimum fluorescence yield following dark adaptation - Fmax maximum fluorescence yield - DCMU 3-(3, 4-dichlorophenyl)-1, 1-dimethyl-urea - DCCD N,N-dicyclohexylcarbodiimide - PQ plastoquinone - DAD diaminodurene Dedicated to Prof. L.N.M. Duysens on the occasion of his retirement.  相似文献   
85.
目的:探寻军医大学学员内隐层面对自我和他人坚毅性评价的特点及脑电特征,为全面、客观的评估个体的坚毅性提供理论依据和客观指标。方法:使用E-Prime2.0参照经典内隐联想范式编制内隐联想-坚毅测验,对100名军医大学学员施测坚毅量表(Grit O),选取高、低坚毅水平被试(各20名)进行内隐联想-坚毅测验,并记录脑电,分析两组被试的内隐效应及主要脑电成分。结果:计算内隐效应D值,t检验显示高坚毅组(0.55±0.36)显著低于低坚毅组(0.87±0.49),t=-2.257,P0.05,Cohen'd=0.74。两组被试均诱发明显的N400和LPP,高坚毅组中N400在任务状态下主效应显著,F(1,17)=8.528,P0.05,η2=0.334,且在电极位置上主效应显著,F(10,170)=8.207,P0.001,η2=0.326。LPP在任务状态下主效应显著,F(1,17)=5.471,P0.05,η2=0.243,且在电极位置上主效应显著,F(10,170)=18.479,P0.001,η2=0.521;低坚毅组中N400在任务状态下主效应显著,F(1,17)=10.051,P0.05,η2=0.372,且在电极位置上主效应显著,F(10,170)=8.223,P0.001,η2=0.326,LPP在任务状态下主效应不显著。结论:1.军医大学学员坚毅性评价的内隐效应显著,即均倾向于认为自我的坚毅性高,他人的坚毅性低,通过问卷法评估坚毅性时应考虑坚毅评价的内隐效应。2.高、低坚毅性军医大学学员坚毅性内隐评价时的主要脑电成分N400、LPP存在差异,N400可作为坚毅性内隐评价符合程度的判断指标。3.内隐效应及N400可以作为对军医大学学员坚毅性评价时的客观指标。  相似文献   
86.
Several types of cryostimulation have been recently proposed to rapidly lower skin temperature therefore gaining a possible neuro/muscular recovery after strenuous exercise or, more generally, in sports. Local cryostimulation may be a viable and relatively portable tool to obtain physiological benefits in previously-efforted muscular districts. However, cohesive and standardized cryo-exposure protocols are lacking as well as the righteous procedure to efficaciously combine duration, treatments and temperature in relation to desirable effects on muscular strength. In this randomized-controlled study, fifty young women were tested for maximum isometric handgrip strength, before and after exhausting contractions.Following the fatiguing protocol, the intervention group (cryo, n = 25, 24.7 ± 2.5 years, BMI 21.7 ± 1.8 kg/m2) underwent a 6-min local cryostimulation (−160 °C) on the extensor-flexor muscles of the dominant arm, while control-matched peers sat rested in a thermo-neutral room (22 ± 0.5 °C). Handgrip tests were repeated at baseline (T0), after cryostimulation (T1), and 15 min after T1 (T2). Throughout the protocol, the AUC of the strength performance was significantly higher in the cryo- compared to control group (P = 0.006). In particular, following fatigue and cryostimulation, the cryo group preserved higher strength at T1 with respect to controls (26.8 ± 2.8 vs 23.9 ± 2.8 kg, Bonferroni's post-hoc, P < 0.01). Likewise, ventral and dorsal temperature, recorded with a thermal camera, were lower in cryo- than control group (P < 0.0001).In conclusion, a brief session of local cryostimulation may acutely preserve maximal isometric force in young women following a fatiguing protocol. These findings may have implications in orchestrating strategies of district muscular recovery.  相似文献   
87.
大比例尺土壤保持服务制图分级方法研究   总被引:2,自引:1,他引:2  
张丹红  王效科  张路  黄斌斌 《生态学报》2021,41(4):1391-1401
科学地编制生态系统服务空间分布图,有助于识别生态系统优先保护热点及空缺,能够为国土安全规划提供基础信息。但由于缺乏统一科学的生态系统服务分级方法,生态系统服务分布图的展示效果和制图效率都受到限制。不恰当的分级制图会误导决策者对生态系统服务空间分布特征的判断,增加生态保护决策的不确定性。以构建生态服务制图分级标准为目标,对我国6个典型县区的土壤保持服务数据展开1:25万比例尺制图分级案例研究。采用分级精度、面积均衡性、极差一致性、空间自相关一致性4个分级质量评价指标评价并比较了目前地图编制中常用的自然断点法、几何间隔法、累积比例法、等差法、分位数法5种分级算法的分级制图效果。结果表明,6个县区有相似的土壤保持服务分布特征:低值区覆盖面积大,高值区覆盖面积小。各县区土壤保持服务制图最优分级方法有差异:延庆区、丰满区最优分级方法为自然断点法;永靖县、天山区、安宁市最优分级方法为累积比例法;富阳区最优分级方法为几何间隔法。各分级方法中,累积比例法在6个县区综合制图效果最优或接近最优,适用性最好,能够较好的刻画各县区的土壤保持服务空间分布特征。本文提出的分级评价方法及其结果,可为生态系统土壤保持服务制图规范化和自动化提供科学依据。  相似文献   
88.
Parental effects are a major source of phenotypic plasticity and may influence offspring phenotype in concert with environmental demands. Studies of “environmental epigenetics” suggest that (1) DNA methylation states are variable and that both demethylation and remethylation occur in post‐mitotic cells, and (2) that remodeling of DNA methylation can occur in response to environmentally driven intracellular signaling pathways. Studies of mother‐offspring interactions in rodents suggest that parental signals influence the DNA methylation, leading to stable changes in gene expression. If parental effects do indeed enhance the “match” between prevailing environmental demands and offspring phenotype, then the potential for variation in environmental conditions over time would suggest a mechanism that requires active maintenance across generations through parental signaling. We suggest that parental regulation of DNA methylation states is thus an ideal candidate mechanism for parental effects on phenotypic variation.  相似文献   
89.
DNA ligases are essential guardians of genome integrity by virtue of their ability to recognize and seal 3′-OH/5′-phosphate nicks in duplex DNA. The substrate binding and three chemical steps of the ligation pathway are coupled to global and local changes in ligase structure, involving both massive protein domain movements and subtle remodeling of atomic contacts in the active site. Here we applied solution NMR spectroscopy to study the conformational dynamics of the Chlorella virus DNA ligase (ChVLig), a minimized eukaryal ATP-dependent ligase consisting of nucleotidyltransferase, OB, and latch domains. Our analysis of backbone 15N spin relaxation and 15N,1H residual dipolar couplings of the covalent ChVLig-AMP intermediate revealed conformational sampling on fast (picosecond to nanosecond) and slow timescales (microsecond to millisecond), indicative of interdomain and intradomain flexibility. We identified local and global changes in ChVLig-AMP structure and dynamics induced by phosphate. In particular, the chemical shift perturbations elicited by phosphate were clustered in the peptide motifs that comprise the active site. We hypothesize that phosphate anion mimics some of the conformational transitions that occur when ligase-adenylate interacts with the nick 5′-phosphate.  相似文献   
90.
In three experiments, rats were trained to perform two instrumental behaviours (R1 and R2) in the presence of discriminative stimuli (Sd1 and Sd2, respectively) to obtain a common food outcome (O1). Acquisition of the two discriminations was followed by switching the outcome accompanying R2 performance from O1 to a new one (O2). Experiment 1 showed paired presentations of O2 with a lithium chloride (LiCl) injection resulted in a reduction in the R2 performance. In the subsequent two experiments, each Sd was paired with LiCl injection and its effects on outcome consumption and instrumental performance were investigated. A reduction in the O2 consumption subsequent to the Sd devaluation was found in Experiments 2 and 3. Experiment 3 revealed a reduced R2 performance in an extinction test, following the animals’ consummatory access to the outcomes in training context. These results demonstrate representation-mediated outcome devaluation in the course of the Sd devaluation.  相似文献   
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