Effects of substituted aryloxyaminopropanols on photosynthesis and photosynthesizing organisms

The inhibitory activity of 22 substituted aryloxyaminopropanols having beta-lytic and local anaesthetic properties was studied from the view-point of their influences on photosynthesis in plant chloroplasts as well as growth and synthesis of chlorophyll in algae and wheat plants. The inhibitory activity increased significantly with the increasing length of alkyl-substituents of the aryloxyaminopropanol molecule. Less pronounced dependences were found with respect to the position of the substituent chain on benzene ring. The inhibitory activity was found to correlate well with the lipophilicity of the compounds studied.     

Measurement of breath-by-breath gas exchange during general anaesthesia using a single pneumotachograph

A breath-by-breath gas exchange measurement system using a single pneumotachograph suitable for use during general anaesthesia is described. The system's accuracy has been assessed by a combination of error sensitivity analysis, laboratory testing of the component measurements used to calculate gas exchange and measurements on volunteers and patients. The system is shown to have a mean accuracy of ± 2.6 ml breath⁻¹ for V_CO2 measurements, ± 7.12 ml breath⁻¹ for V_O2 and ± 5.55 ml breath⁻¹ for V_N2O measurement. The application of a lung gas stores correction using argon improved between breath variability by 50%.     

Measurement and analysis of gas exchange during exercise using a programmable calculator

Although exercise testing is useful in the diagnosis and management of cardiovascular and pulmonary diseases, a rapid comprehensive method for measurement of ventilation and gas exchange has been limited to expensive complex computer-based systems. We devised a relatively inexpensive, technically simple, and clinically oriented exercise system built around a desktop calculator. This system automatically collects and analyzes data on a breath-by-breath basis. Our calculator system overcomes the potential inaccuracies of gas exchange measurement due to water vapor dilution and mismatching of expired flow and gas concentrations. We found no difference between the calculator-derived minute ventilation, CO2 production, O2 consumption, and respiratory exchange ratio and the values determined from simultaneous mixed expired gas collections in 30 constant-work-rate exercise studies. Both tabular and graphic displays of minute ventilation, CO2 production, O2 consumption, respiratory exchange ratio, heart rate, end-tidal O2 tension, end-tidal CO2 tension, and arterial blood gas value are included for aid in the interpretation of clinical exercise tests.     

Measurement of respiratory gas exchange during artificial respiration

This paper reports a new system for the continuous measurements of respiratory gas exchange in ventilated subjects. It involves mixing some of the inspired gas with all of the expired gas and withdrawing the mixture at a constant rate through a dry gas meter that measures the flow. The inspired gas and expired gas mixtures are sampled and O2 and CO2 concentrations measured with a paramagnetic gas analyzer and a capnograph, respectively, to an accuracy of 0.01%. Evidence is presented to confirm the necessary stability and sensitivity of these instruments. It is possible to use the system with high inspired O2 concentrations, with ventilators where there is incomplete separation of inspired and expired gas, and in the presence of intermittent mandatory ventilation, positive end-expiratory pressure, and continuous airway pressure. The system was compared with the N2-dilution method and with the collection of expired gas in a Douglas bag in dog experiments and with patients in the intensive therapy unit. Excellent correlation between these methods was found in all circumstances.     

Anion exchange chromatographic separation of inositol phosphates and their quantification by gas chromatography

The direct measurement of mass of inositol trisphosphate from biologic samples is described. Separation of inositol monophosphate, bisphosphate, trisphosphate, and inositol tetrakisphosphate was achieved using anion exchange chromatography with a sodium sulfate gradient. In addition, separation of the isomers of each inositol phosphate was performed using HPLC procedures. The individual inositol phosphate fractions were subsequently dephosphorylated and desalted. The myo-inositol from each fraction was then derivatized to the hexatrimethylsilyl derivative and the myo-inositol derivatives were quantified by a novel gas chromatographic analysis using the hexatrimethylsilyl derivative of chiro-inositol as an internal concentration reference. This method is a reproducible and relatively rapid procedure for the direct quantification of inositol phosphate mass which overcomes many of the problems associated with the use of radiolabeled precursors. The method is a significant improvement over existing procedures for the quantitative determination of the mass of inositol phosphate by virtue of improved recovery, sensitivity, and technical simplicity. The applicability of this method is illustrated by the quantitative determination of inositol trisphosphate in response to norepinephrine stimulation of adult canine myocytes and cerebral cortical brain slices and by measurement of the isomers of inositol trisphosphate in isolated myocytes.     

Measurement of choline and choline metabolite concentrations using high-pressure liquid chromatography and gas chromatography-mass spectrometry

We have developed a reproducible and sensitive procedure for the isolation and measurement of choline, phosphocholine, glycerophosphocholine, phosphatidylcholine, lysophosphatidylcholine and acetylcholine in a single 100-mg sample of biological tissue. Tissues were spiked with 14C-methyl- and 2H-methyl- or 15N-choline labeled internal standards for each compound. They were extracted with chloroform/methanol/water and the aqueous and organic phases were dried. The organic phase was resuspended in chloroform/methanol (1/1, v/v) and an aliquot was applied to a silica-gel thin-layer chromatography plate. The plate was developed in chloroform/methanol/water (65/30/4, v/v). Segments which cochromatographed with external standards of phosphatidylcholine and lysophosphatidylcholine were stained, scraped, and hydrolyzed in 6 M methanolic-HCl at 80 degrees C for 60 min, liberating free choline. The aqueous phase was resuspended in methanol/water and injected onto a silica HPLC column. Choline and its metabolites were eluted using a binary nonlinear gradient of acetonitrile/ethanol/acetic acid/1 M ammonium acetate/water/0.1 M sodium phosphate (800/68/2/3/127/10, v/v changing to 400/68/44/88/400/10, v/v). Peaks were detected with an on-line radiometric detector, collected, and dried under vacuum. Each choline ester was digested in 6 M HCl at 80 degrees C to form choline. Choline was then converted to the propionyl ester and demethylated with sodium benzenethiolate. This volatile derivative was then isolated using gas chromatography and measured with a mass selective detector. Deuterated internal standards were used to correct for variations in recovery. Choline, glycerophosphocholine, phosphocholine, phosphatidylcholine, lysophosphatidylcholine, and acetylcholine were measured in rat liver, heart, muscle, kidney, plasma, red blood cells, and brain and in human plasma.(ABSTRACT TRUNCATED AT 250 WORDS)     

Enantiomeric analysis of amino acids by using comprehensive two-dimensional gas chromatography

The chiral separation of amino acids (AA) derivatised with ethyl chloroformate by using comprehensive two-dimensional gas chromatography is reported. A commercially available enantioselective capillary column (Chirasil-l-Val) has been tested as first-dimension column. Two nonenantioselective stationary phases (BPX50 and BP1) with different column lengths were combined with the enantioselective column, which represent chiral/polar and chiral/low-polarity column sets, respectively. These column sets were evaluated to determine the most useful column combination to provide improved separation efficiency of enantioselective AA analysis. Separations of AA mixtures derivatised either as their N-trifluoroacetyl methyl esters or with methyl chloroformate, performed on a chiral/low-polarity column set, are also shown. The method was demonstrated for chiral analysis of AAs in different beer samples. The major AA in the beer samples was proline with amounts ranging from around 65-95% with minor contents of glycine and the l-enantiomers of alanine, valine, leucine, and isoleucine. Small amounts of d-alanine, at about 1, 1.5, and 15% were detected in the three samples.     

顶空气相色谱法检测破伤风抗毒素中的甲苯残留量

目的建立检测破伤风抗毒素中甲苯残留量的顶空气相色谱法。方法参照《中国药典》三部(2015版)"残留溶剂测定法",采用Agilent DB-1301毛细管色谱柱(15.0 m×530μm×1.00μm)及氢火焰离子化检测器;顶空进样器各参数分别为:平衡温度70℃,平衡时间30 min,定量环温度80℃,传输线温度90℃,进样量1 m L;气相色谱仪各参数为:进样室温度100℃,柱温箱温度60℃,检测器温度220℃,载气氮气流速5 m L/min,采集时间5min;并对该方法的系统适用性、专属性、线性范围、准确度和精密度、检测限和定量限进行验证及初步应用。结果甲苯保留时间2.429 min,峰面积的RSD为1.9%,以甲苯色谱峰计算得到的理论塔板数N=12 900,甲苯色谱峰与其相邻色谱峰的分离度R=6.03。方法的专属性强,制品中的其他物质不干扰甲苯的出峰;标准曲线的范围为1.0×10-4%~2.0×10-3%,相关系数r大于0.99;加标试验的回收率分别为96.0%~102.9%、100.7%~111.0%,重复性和日间精密度RSD均小于5%。检出限为2.6×10-6%,定量限为1.0×10-5%。测定10批破伤风抗毒素成品和10批破伤风抗毒素原液,其甲苯残留量均低于检出限,远低于规定的限度0.089%。结论该方法简便、快速、准确度、灵敏度高、精密度好,适用于破伤风抗毒素类制品中甲苯残留量的检测。     

Measurement of gas exchange rates in plant tissue culture vessels

The aerial microenvironment in culture vessels has a significant effect on the growth and development of plantlets in vitro. Since the gas exchange between outside air and inner air can influence the microenvironment of culture vessel, it is necessary to measure the air exchange rate for various vessels. In this study, water vapor was used as the tracer gas, and the change of absolute humidity inside the vessel was calculated continuously by the measured values of a relative humidity sensing element. The outside environment was maintained at constant humidity level by a saturated salt solution. The RH data were transformed into absolute humidity and the specific humidity ratio. The air exchange rates of several tissue culture vessels were then calculated. The exchange rate was between 0.0145 h^–1 to 0.0376 h^–1. This technique provides an inexpensive, rapid and simple way to determine the air exchange rate of a culture vessel within a short period. The effects of the air current velocities on the exchange rates of vessels were also determined.     

Recent advances in ascorbate biosynthesis and the physiological significance of ascorbate peroxidase in photosynthesizing organisms

Ascorbate (AsA), the most abundant water-soluble redox compound in plants and eukaryotic algae, has multiple functions. There is compelling genetic evidence that the biosynthesis of AsA proceeds via a D-mannose/L-galactose pathway and is the most significant source of AsA in plants. AsA plays important roles in antioxidative defense, particularly via the AsA/glutathione cycle. AsA peroxidase (APX) plays a central role in the cycle and is emerging as a key enzyme in cellular H(2)O(2) metabolism. Plants possess diverse APX isoenzymes in cellular compartments, including the chloroplast, cytosol, and microbody. In algae, however, the number and distribution of APX proteins are quite limited. Recent progress in molecular biological analysis of APX isoenzymes has revealed elaborate mechanisms for the tissue-dependent regulation of two chloroplastic APX isoenzymes by alternative splicing, and for redox regulation of cytosolic APX gene expression in response to light stress. Furthermore, transgenic plants overexpressing a chloroplastic APX isoenzyme enable us to evaluate the behavior of the enzyme under conditions of photo-oxidative stress. Molecular physiological analysis has revealed that cytosolic APX is part of the system modulating the cellular H(2)O(2) level in redox signaling.     

Analysis of glycoprotein oligosaccharides using high-pH anion exchange chromatography

The natural heterogeneity of glycoprotein glycans requires that chromatography be an essential part of structural elucidation. The isomeric nature of oligosaccharide structure requires chromatography which is selective for not only composition, size and anomerity, but also ring substitutions and branching configurations. HPAEC is sensitive to these structural features and thus, has become an important new method for understanding the elusive function of glycoprotein glycans.