Determination of l-glutamate in various commercial soy sauce products using flow injection analysis with a modified electrode

A flow injection analysis (FIA) system with a modified electrode has been developed and optimized for determination of l-glutamate using l-glutamate oxidase (GLOD) (EC 1.4.3.11). GLOD was immobilized on controlled-pore glass using glutaraldehyde. The optimal potential applied on the working electrode was +700mV against a platinum (Pt) reference electrode. The optimal pH and flow rate of the carrier buffer were 7.4 and 1.5ml/min, respectively. A modified electrode was integrated into the FIA system in order to eliminate electroactive interference and it was used to determine l-glutamate in 39 samples of Thai commercial soy sauce products. The results obtained were compared with those obtained from enzymatic assay using glutamate dehydrogenase and those from a chromatographic assay using an amino acid analyser. Good correlations were observed amongst these methods. The results indicated that use of an FIA system with a modified electrode was able to eliminate electroactive interference and was applicable to the determination of l-glutamate in food samples. The modified FIA was faster and simpler than the more common methods of enzymatic and chromatographic analysis.     

Anxiolytic effect of motilin and reversal with GM-109, a motilin antagonist, in mice

There have been few reports on the effects of the brain-gut peptide motilin on the central nervous system (CNS). We administered motilin intracerebroventricularly to mice and investigated the effect of motilin on anxiety using an elevated plus-maze. Motilin produced a significant decrease in anxiety with an inverted U-shaped dose response. To determine whether the anxiolytic effect of motilin was mediated via motilin receptors in the brain, the effect of GM-109, a novel motilin receptor antagonist, was investigated. GM-109 showed a significant and dose-dependent antagonism on the motilin-induced anxiolytic effect. GM-109 administered alone had no effect on anxiety. These results suggest that motilin receptors are present in the brain and may have a role in anxiety and emotion.     

内皮素-1前体基因反义寡核苷酸对正常和高血压大鼠血流动力学的影响

我们筛选出针对内皮素－１（ＥＴ－１）前体基因反义硫代寡核苷酸片断（ＥＴＡＳＯＤＮ）,已证明ＥＴＡＳＯＤＮ能显著抑制培养内皮细胞ＥＴ－１的生成,本应用该片断,对下沉和腹主动脉狭窄－高盐摄入型高血压大鼠侧脑室进行注射,记录注射前后血流动力学指标、注射后侧脑室周围组织中ＥＴ－１的含量及分布,ＥＴＡＳＯＤＮ对正常和高血压大鼠的影响,发现高血压大鼠脑干ＥＴ－１含量明显高于正常大鼠;ＥＴＡＳＯＤＮ能降低高血压     

Use of a micro-expanded bed containing immobilised lysozyme for cell disruption in flow injection analysis

A method for cell disruption in Flow Injection Analysis (FIA) systems has been developed. The principle involves on-line cell disruption by means of immobilised lysozyme followed by an ultrasonic treatment. In order to avoid flow problems in the analytical system, the lysozyme was immobilised to Streamline^reg that was used in an expanded bed in the flow system. Samples of suspensions of Micrococcus lysodeikticus were treated and the success of the treatment was evaluated in terms of released protein and as a decrease in the optical density at 450 nm. The new technology offers a powerful tool in flow injection analyses for quantification of intracellular compounds. The concept of integration, i.e. combining cell disruption with handling of cell debris and assay procedure in one continuous flow process facilitates its use and increases the probability of reaching reproducible and reliable results.     

A low temperature microbial biosensor using immobilised psychrophilic bacteria

A psychrophilic bacteria, Deinococcus radiodurans, was used to construct a biosensor to be used in a flow injection system. The transducer used was an O₂ electrode. The response of this cell-based electrode was studied towards a number of sugars. The temperature dependence of the electrode response correlated well with the behavior of the cells. Thus, the optimum temperature for measurement of glucose (0.55 mM) was about +5°C. Since the organism used is psychrophilic, a response time at this low temperature is similar to what is achieved with mesophilic organisms at room temperature. This is the first biosensor constructed using a psychrophilic microorganism.     

Determination of procaine hydrochloride using flow injection inhibitory chemiluminescence

A new flow injection chemiluminescent method has been developed for the determination of procaine hydrochloride, based on the inhibition of the chemiluminescence reaction of luminol–hydrogen peroxide by procaine hydrochloride. The influence of several surfactants and β‐cyclodextrin on the chemiluminescence intensity were studied. It was found that β‐cyclodextrin enhanced the decrease in chemiluminescence intensity. The method is simple, convenient and sensitive, with a detection limit (3 σ) of 0.08 µg/mL. The decreased chemiluminescence intensity is linear, with the concentration of procaine hydrochloride in the range 0.2–100.0 µg/mL and 100.0–400.0 µg/mL. The relative standard deviation for 10 repeated measurements were 4.5% and 3.4% for 1.0 and 20.0 µg/mL procaine hydrochloride, respectively. The method has been successfully applied to the determination of procaine hydrochloride in injection solutions of this drug. Copyright © 2003 John Wiley & Sons, Ltd.     

Determination of parathion residues in rice samples using a flow injection chemiluminescence method

A sensitive ?ow injection chemiluminescence method is described for the determination of parathion pesticide, based upon its direct chemiluminescence reaction with luminol and hydrogen peroxide in the presence of non‐ionic surfactant polyethylene glycol 400. Under the selected experimental conditions, the concentration of parathion is proportional to the CL intensity in the range 0.02–1.0 mg/L. The detection limit was 0.008 mg/L and the relative standard deviation was 2.8% for 0.2 mg/L parathion solution (n = 11). This method was successfully applied to the determination of parathion residue in rice samples. Copyright © 2003 John Wiley & Sons, Ltd.     

Hydrazine-induced post-chemiluminescence phenomenon of permanganate-luminol reaction and its applications.

The post-chemiluminescence phenomenon arising from the permanganate-luminol reaction induced by hydrazine and isoniazid was investigated. When hydrazine or isoniazid was injected into the mixture after the end of the reaction of permanganate with alkaline luminol, a new chemiluminescence (CL) reaction was initiated and strong CL signal was detected. A possible CL mechanism is suggested, based upon the studies of the kinetic characteristics of the CL reaction, the UV-visible spectra, the CL spectra and some other experiments. The present reactions allow the determination of 0.1-10.0 mg/L hydrazine and 0.02-1.0 mg/L isoniazid, with detection limits of 0.03 mg/L and 0.006 mg/L, respectively. The method was applied to the determination of isoniazid in pharmaceutical preparations.     

Flow injection assays with chemiluminescence and bioluminescence detection — A review

This paper reviews publicaions that combine the technique of flow injection (FI) with chemiluminescence (CL) and bioluminescence (BL) detection, from the earliest papers in 1979/80 to mid-1992, and refers exclusively to reactions occurring in solution. Airsegmented systems and liquid chromatography with CL detection are not considered unless FI has been used to pre-optimize the system. The applications have been categorized in terms of the type of CL reaction; there are separate entries for luminol, peroxyoxalate, other CL reactions and BL reactions. Each of the four sections includes a table of applications that lists the analyte, the nature of the reaction, the sample matrix and the limit of detection.     

鼠神经生长因子联合神经节苷脂钠注射液对癫痫大鼠认知功能、血清NSE及海马神经元的影响及机制分析

摘要 目的：探讨鼠神经生长因子联合神经节苷脂钠注射液对癫痫大鼠认知功能、血清NSE及海马神经元的影响。方法：选择SD雄性大鼠50只,随机分为5组,包括空白组、模型组、A组、B组、C组。空白组大鼠腹腔注射等容量的生理盐水,其余组使用腹腔注射氯化锂-毛果芸香碱的方法建立癫痫大鼠模型。空白组、模型组大鼠用微量注射器注射20 μL无菌生理盐水,A组同时间点给大鼠腹腔注射2000 AU/kg鼠神经生长因子;B组同时间点给大鼠腹腔注射20 μL神经节苷脂钠;C组给大鼠腹腔注射2000 AU/kg鼠神经生长因子联合20 ?滋L神经节苷脂钠。进行Morris水迷宫试验、空间探索试验,检测血清NSE水平与海马神经组织的神经元,检测血清NSE水平、海马神经组织的神经元存活率及核因子kB p56、TLR-4、MyD88蛋白水平。结果：模型组第1、2、3、4、5 d时的游泳总距离、逃避潜伏期较其他四组高,空白组较A组、B组、C组高,B组、A组较C组高（P<0.05）,B组、A组对比无差异（P>0.05）;模型组的平台穿越次数、探索有效时间比率较空白组、A组、B组、C组低,空白组较A组、B组、C组低,B组、A组较C组低（P<0.05）,B组、A组对比无差异（P>0.05）;模型组的血清NSE水平、核因子kB p56、TLR-4、MyD88蛋白水平较空白组、A组、B组、C组低,海马组织中神经元存活率较高,空白组较A组、B组、C组低,海马组织中神经元存活率较高,B组、A组较C组低,海马组织中神经元存活率较高（P<0.05）,B组、A组的NSE水平、海马组织中神经元存活率、核因子kB p56、TLR-4、MyD88蛋白水平对比无差异（P>0.05）。结论：鼠神经生长因子联合神经节苷脂钠注射液可改善癫痫大鼠的认知功能,减轻海马组织炎症反应,可能与其可降低血清NSE及海马组织核因子kB p56、TLR-4、MyD88水平有关。