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981.
Deriving C4 photosynthetic parameters from combined gas exchange and chlorophyll fluorescence using an Excel tool: theory and practice 下载免费PDF全文
The higher photosynthetic potential of C4 plants has led to extensive research over the past 50 years, including C4‐dominated natural biomes, crops such as maize, or for evaluating the transfer of C4 traits into C3 lineages. Photosynthetic gas exchange can be measured in air or in a 2% Oxygen mixture using readily available commercial gas exchange and modulated PSII fluorescence systems. Interpretation of these data, however, requires an understanding (or the development) of various modelling approaches, which limit the use by non‐specialists. In this paper we present an accessible summary of the theory behind the analysis and derivation of C4 photosynthetic parameters, and provide a freely available Excel Fitting Tool (EFT), making rigorous C4 data analysis accessible to a broader audience. Outputs include those defining C4 photochemical and biochemical efficiency, the rate of photorespiration, bundle sheath conductance to CO2 diffusion and the in vivo biochemical constants for PEP carboxylase. The EFT compares several methodological variants proposed by different investigators, allowing users to choose the level of complexity required to interpret data. We provide a complete analysis of gas exchange data on maize (as a model C4 organism and key global crop) to illustrate the approaches, their analysis and interpretation. © 2015 John Wiley & Sons Ltd 相似文献
982.
James E. Evans Howard Tieckelmann Edwin W. Naylor Robert Guthrie 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1979,163(1):29-36
A rapid procedure for the isolation, separation, identification and measurement of urinary pyrimidine bases and nucleosides by high-performance liquid chromatography (HPLC) is presented. The initial isolation of these compounds from urine was accomplished with small disposable ion-exchange columns. HPLC was performed on a silica gel column with a mobile phase composed of methylene chloride, methanol and 1 M aqueous ammonium formate buffer. Peaks were recorded at both 254 nm and 280 nm and the response ratio was used in conjunction with the elution volume for compound identification. The minimum detectable amount (signal-to-noise ratio = 2) ranged from 0.2 ng for uracil to 2.2 ng for cytidine. Linearity and recovery for thymine, uracil, uridine, pseudouridine, orotic acid and orotidine added to urine was demonstrated over almost a 103 concentration range. The potential application of this method for the study of inborn errors in the urea cycle is discussed. 相似文献
983.
Brett A. Larson Prof. Howard A. Bern Richard J. Lin Richard S. Nishioka 《Cell and tissue research》1987,247(2):233-239
Summary A double immunofluorescence method was devised to localize simultaneously urotensin-I (UI) and -II (UII) immunoreactivities in the caudal neurosecretory system of the goby, Gillichthys mirabilis. In a sequential fashion, sections of the posterior spinal cord and urophysis were treated with antiserum to corticotropin-releasing factor (CRF) that cross-reacts with UI, fluorescein-conjugated sheep anti-rabbit IgG, biotinylated anti-UII and rhodamine-conjugated avidin. UI and UII immunoreactivities appeared to coexist in some neurons and in most fibers and urophysial tissue; the remainder of the fibers and urophysis and the majority of neurons were immunoreactive for CRF/ UI only. No convincing evidence of immunoreactivity for UII only was found. A few nonreactive cells were seen, but these may not be neurosecretory neurons. The two immunoreactive cell types were not segregated topographically, and the intensity of perikaryal immunofluorescence for CRF/UI was variable. To explain these results a hypothesis that all caudal neurosecretory cells may synthesize both UI and UII and that immunoreactive differences may reflect different states of cellular activity, is suggested. This sequential double immunofluorescence method offers several advantages over other techniques and is especially useful for co-localization studies when primary antisera from different species are not available. 相似文献
984.
985.
Masterson LA Spanswick VJ Hartley JA Begent RH Howard PW Thurston DE 《Bioorganic & medicinal chemistry letters》2006,16(2):252-256
The design, synthesis and evaluation of four novel pyrrolo[2,1-c][1,4]benzodiazepine (PBD) prodrugs (1a,b and 2a,b; ) for potential use in carboxypeptidase G2 (CPG2)-based antibody-directed enzyme prodrug therapy (ADEPT) is reported. Although all four prodrugs were shown to be less cytotoxic than the released parent PBDs 3 and 4, the urea prodrugs 1b and 2b were found to be too unstable for use in ADEPT, whereas carbamates 1a and 2a are both stable in an aqueous environment and are good substrates for CPG2. 相似文献
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987.
988.
The impact of cold-water immersion on power production in the vertical jump and the benefits of a dynamic exercise warm-up 总被引:1,自引:0,他引:1
Dixon PG Kraemer WJ Volek JS Howard RL Gomez AL Comstock BA Dunn-Lewis C Fragala MS Hooper DR Häkkinen K Maresh CM 《Journal of strength and conditioning research / National Strength & Conditioning Association》2010,24(12):3313-3317
The purpose of this study was to examine the influence of a cold treatment and a dynamic warm-up on lower body power in the form of a countermovement vertical jump (CMVJ). Nine physically active men, who were either current or ex-National Collegiate Athletic Association (NCAA) Division 1 athletes, consented to participate in the study. Using a balanced, randomized presentation and a within-subject design, each subject performed 4 environmental and warm-up protocols (i.e., ambient temperature without warm-up, ambient temperature with warm-up, cold without warm-up, or cold with warm-up). Two sets of 3 maximal effort CMVJs were performed on a force plate at each testing time point. For each protocol, the subjects completed a pretest set of CMVJ (pretreatment [PRE]), were then exposed to 1 of the 2 temperature treatments, completed another set of CMVJ (initial [IT]), then either went through a 15-minute warm-up, or were asked to sit in place. Then a final set of CMVJs was completed (posttreatment [PT]). The primary finding in this study was that warm-up was effective in offsetting the negative effects of cold exposure on CMVJ power. There was a significant main effect for Time (PRE > PT > IT), and there was a significant (p ≤ 0.05) main effect for Trial (AMB = AMBWU > COLDWU > COLD). Because athletic competitions happen in various colder climates, it is important to make sure that a proper warm-up be completed to maximize the athlete's power output. The results of this study demonstrate that when athletes are exposed to cold conditions, it is recommended that before practice or play, a dynamic warm-up be employed to optimize performance. 相似文献
989.
Kouroush Sadegh Zadeh Howard C Elman Hubert J Montas Adel Shirmohammadi 《Biomedical engineering online》2007,6(1):24