A rapid method of oxymyoglobin purification

Oxymyoglobin was isolated from bovine Longissimus lumborum muscle by precipitation with ammonium sulfate and purification in rapid conditions with only one chromatographic step on Mono-Q HR column with a HPLC system. Purity of oxymyoglobin was controlled by SDS-polyacrylamide gel electrophoresis and isoelectrofocusing.     

A simple and rapid method for isolating cassava leaf linamarase suitable for cassava cyanide determination

A simple method was developed for isolating cassava leaf linamarase. It involved homogenising the leaves in a buffer containing polyvinylpolypyrrolidone, followed by ammonium sulphate precipitation, filtration and partial purification of the enzyme by hydrophobic interaction chromatography. All stages of the enzyme preparation were carried out at room temperature and it was completed within 90 min. A linamarin-indicator strip for checking the activity of the enzyme preparation was also developed. This isolation technique which has been developed into a simple kit should be suitable for laboratories in developing countries where the enzyme is needed to determine the cyanogenic potential of cassava and its products. © 1997 SCI.     

乳酸菌质粒DNA高效快速提取方法的建立

采用酶裂解和碱裂解相结合的方法,并参考质粒DNA提取原理,建立了一种高效快速的乳酸菌质粒DNA提取方法.结果表明,在乳酸菌中可获得一个到多个高质量的质粒DNA,分子大小不等,浓度10mg/mL左右,1.8＜A260/A280＜2.0.该方法减少了通常乳酸菌质粒DNA提取方法的提取和纯化步骤,减少了乳酸茵质粒DNA提取时间和损失,是一种高效快速的乳酸茵质粒DNA提取方法.     

大蒜中大蒜素含量简便测定法

采用一种快速简便的分光光度法测定大蒜中的大蒜素含量.研究测定过程中半胱氨酸反应浓度、反应时间、反应温度及反应体系pH值等因素对测定结果的影响.优选出最佳测定条件,提高测定的准确性和重现性.     

大孔吸附树脂对茄皮红色素的分离纯化研究

运用静态吸附与解吸试验对5种大孔吸附树脂进行筛选,然后通过单因素试验、正交试验和方差分析确定大孔树脂吸附茄子皮红色素的最佳操作条件.结果表明,HPD-100树脂对茄子皮红色素的吸附和解吸性能较好,确定的最佳吸附条件为A2B2C2,即料液浓度(以吸光度计)为0.435Abs,上柱速率为3.0 BV/h,pH值为2.53.     

超声波辅助水解法制备高纯度大豆异黄酮工艺研究

以低纯度商品大豆异黄酮为原料,利用超声波辅助酸水解技术制备高纯度大豆异黄酮甙元产品。通过实验,比较系统深入研究超声波功率、超声波处理时间、反应温度、水解酸度等因素对水解效果影响,并最终得到超声波辅助水解最佳工艺参数。实验结果表明,超声波处理对大豆异黄酮甙水解有一定促进作用,超声波辅助水解大豆异黄酮最佳工艺条件为:超声波功率80W,水解时间1h,反应温度70℃,酸度为1M;通过超声波辅助水解提取后,所得产品纯度由原来25.3%提高至93.20%。     

Simple and rapid microbiological method for determination of residual antibacterials in meat

A simple and rapid screening method using bioassay for the simultaneous analysis of antibacterials (penicillins, cephalosporins, macrolides, tetracyclines, quinolones, etc.) in meat has been developed. A 5 g sample was homogenized with 5 mL of methanol, and the homogenate was centrifuged for 10 min with 3,000 rpm. The pulp disk method with Bacillus subtilis BGA (Antibiotic Medium 5 (pH 8) and 8 (pH 6)), Micrococcus luteus ATCC 9341 and Geobacillus stearothermophilus as test organisms was employed for the assay of the antibacterials. Typical antibacterials (penicillin G, ampicillin, cefapirin, cefalexin, erythromycin, spiramycin, oxytetracycline, chlortetracycline, streptomycin, dihydrostreptomycin, enrofloxacin and oxolinic acid) were detected at levels of ca. 0.005-2.5 microg/g in meat. Therefore, we recommend this proposed screening method for routine analysis of residual antibacterials in livestock products.     

Insertional chromatin immunoprecipitation: A method for isolating specific genomic regions

We established a novel method, insertional chromatin immunoprecipitation (iChIP), for isolation of specific genomic regions. In iChIP, specific genomic domains are immunoprecipitated with antibody against a tag, which is fused to the DNA-binding domain of an exogenous DNA-binding protein, whose recognition sequence is inserted into the genomic domains of interest. The iChIP method will be a useful tool for dissecting chromatin structure of genomic region of interest.     

纺织品卫生整理抗菌防臭检验法

简要介绍了纺织品进行抗菌防臭整理的意义和主要的防菌剂。重点介绍了抗菌防臭卫生整理加工的检验操作过程及方法：AATCC尝试法,改良法等。     

A rapid, sensitive and economic method for the detection, quantification and confirmation of aflatoxins

Summary A rapid, sensitive and economic method for the detection, quantification and confirmation of aflatoxins is described. Aflatoxins B₁, B₂, G₁, and G₂, are extracted by methanol/water (85+15) and partitioned into methylene dichloride. The methylne dichloride solution is cleaned up on a polypropylene column, filled with 0.5 g silica gel 60. The aflatoxins are eluted with cloroform-acetone (90:10) and are detected using bidirectional thin-layer chromatography (TLC) with aluminium silica gel foil. The mean recovery of aflatoxins B₁, B₂, G₁, and G₂, in corn samples was 73, 78, 80, and 64%, respectively; the limit of detection was 0.5 g/kg. The results can also be confirmed by derivative formation using trifluoroacetic acid on the TLC plate. The method has been applied to a wide range of foods with good results.

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Eine schnelle, empfindliche und kostengünstige Methode zum Nachweis, zur Bestimmung und Bestätigung von Aflatoxinen

Zusammenfassung Es wird eine schnelle, empfindliche und kostengünstige Methode zum Nachweis, Bestimmung und Bestätigung von Aflatoxinen beschrieben. Die Aflatoxine B₁, B₂, G₁ und G₂ werden mit Methanol/Wasser (85+15) extrahiert und in Dichlormethan überführt. Der Dichlormethanextrakt wird auf einer mit 0,5 g Kieselgel 60 gefüllten Polypropylensäule gereinigt. Die Aflatoxine werden mit Chloroform/Aceton (90+10) eluiert und mit zweidimensionaler DC auf Kieselgel-Alufolien nachgewiesen. Die mittleren Wiederfmdungsraten für die Aflatoxine B₁, B₂, G₁ und G₂ in Maismehl betragen 73, 78, 80 und 64%, die Nachweisgrenzen liegen durchschnittlich bei 0,5 g/kg. Zur Bestätigung verdächtiger Befunde kann auf der Platte mit Trifluoressigsäure derivatisiert werden. Die Methode ist bisher an einer Vielzahl von verschiedenen Lebensmitteln mit gutem Erfolg getestet worden.

     

一种快速测定酶活性的方法

目的探讨快速测定酶活性的方法。方法直接用生物传感分析仪测相对的酶活性,并与测定绝对酶活性的方法相对照,探讨它们之间的关系。结果直接用生物传感分析仪测相对酶活性可判断乳酸氧化酶的活性,与测定绝对酶活性的方法相比,它们存在着线性关系。结论直接用生物传感分析仪测相对酶活性是一种快速判断酶活性值的方法。它还可以测定谷氨酸氧化酶、葡萄糖氧化酶等的酶活性。     

1种快速检测微藻油脂的新方法

微藻油脂是一种非常重要的生物能源,微藻产油能力及油脂含量变化的快速分析在能源微藻的产业化过程中有着很重要的意义。文中以实验室分离的1株栅藻为研究对象,以有机溶剂提取法作为参照,利用磷酸香草醛反应法监测了在不同的糖浓度、氮浓度和磷浓度下栅藻油脂含量的变化。同时,对其他微藻,如小球藻、小环藻、脆杆藻等应用磷酸香草醛反应法进行总脂量分析。结果表明,磷酸香草醛反应法可以快速准确地检测微藻油脂的含量。     

Simple and rapid analytical method for the simultaneous determination of cetrimonium chloride and alkyl alcohols in hair conditioners

A simple method for the simultaneous determination of a cationic surfactant (cetrimonium chloride) and four non-ionic surfactants (1-tetradecanol, 1-hexadecanol, 1-octadecanol and 1-eicosanol) has been developed. Direct extraction of the analytes from the sample with methanol and a subsequent separation using reversed-phase high-performance liquid chromatography with refractive index detection are the steps followed in the procedure. The column used was a Luna C18 and the mobile phase consisted of a 0.1 M KClO₄ solution prepared on a 95:5 mixture of methanol and water. This solution was adjusted to pH 2.8 with phosphoric acid. Recoveries close to 100% were obtained in spiked commercial hair conditioner samples for the surfactants assayed using this method. Limits of detection were 10.4, 16.7 and 22.9 mg kg⁻¹ of cetrimonium chloride, 1-hexadecanol, 1-hexadecanol and 1-1-octadecanol respectively. The methodology was successfully applied to nine commercial hair conditioners of several types and different brands. All hair conditioners but one contained at least two of the surfactants included in this study.     

A rapid, sensitive and economic method for the detection, quantification and confirmation of aflatoxins.

A rapid, sensitive and economic method for the detection, quantification and confirmation of aflatoxins is described. Aflatoxins B1, B2, G1, and G2, are extracted by methanol/water (85 + 15) and partitioned into methylene dichloride. The methylene dichloride solution is cleaned up on a polypropylene column, filled with 0.5 g silica gel 60. The aflatoxins are eluted with chloroform-acetone (90:10) and are detected using bidirectional thin-layer chromatography (TLC) with aluminium silica gel foil. The mean recovery of aflatoxins B1, B2, G1, and G2 in corn samples was 73, 78, 80, and 64%, respectively; the limit of detection was 0.5 micrograms/kg. The results can also be confirmed by derivative formation using trifluoroacetic acid on the TLC plate. The method has been applied to a wide range of foods with good results.     

A simple, rapid and sensitive method for monitoring contamination of aseptically processed tomato paste

A simple, rapid and sensitive method for the detection of microbial contamination of the system of aseptically processing tomato paste has been developed. The method involves the rapid growth of any lactobacilli present in the product and detection of metabolites produced by these micro-organisms. The metabolites used are acetoin, diacetyl, carbon dioxide and lactic acid. It was found that with this method it is possible to detect the presence of both homofermentative and heterofermentative lactobacilli within 10–25 hr, depending on the level of contamination.     

A rapid,simple and sensitive fluorescence method for the assay of angiotensin-I converting enzyme

A fluorescent assay for angiotensin-I converting enzyme (ACE; EC 3.4.15.1) is described. It is based in the hydrolysis of the internally quenched fluorescent substrate o-aminobenzoylglycyl-p-nitrophenylalanylproline by the action of ACE. The fluorescence generated by the liberation of the product (the o-aminobenzoylglycine group) is read in a microtiter-plate multiscan fluorometer. The different conditions for the assay have been optimised for linearity, sensitivity and precision. Maximal enzyme activity was reached in the pH range 8.0–8.5 and 0.5–0.75 M NaCl concentration in the assay mixture. Kinetics of the enzyme reaction displayed a K_m = 109 μM, obtaining an optimal substrate concentration of 0.3 mM in the assay mixture. The assay was adequate for the study of ACE inhibition by captopril and several peptides and it also showed a very good correlation with a well-established method [Biochemical Pharmacology, 20(7) (1971) 1637]. The method has important advantages, being the availability of reagents, its simplicity and the capacity to process a high number of samples in a short time, most outstanding.     

Simple and rapid cell growth assay using tetrazolium violet coloring method for screening of organic solvent tolerant bacteria

Tolerance to organic solvents is an important characteristic for selecting bacteria that are useful for producing commodity chemicals. An assay method for tolerance should be easy to perform and differences in tolerance should be reproducible. We propose a cell growth assay using tetrazolium violet and image analysis for assessing tolerance. When five microorganisms including Escherichia coli were tested, the organic solvent tolerance (OST) of microorganisms used was rapidly and qualitatively assessed and the degrees of OST coincided with those from the conventional method using solvent overlaid-solid medium. Moreover, the proposed method was applicable to the estimation of OST for cyclohexane resistant E. coli OST3410 using various organic solvent mixtures.     

A simple and rapid turbidimetric method for determining catechins in beverages

We have developed a simple and rapid turbidimetric method to determine catechins based on the fact that many polyphenols produce hydrogen peroxide in an alkaline environment and that hydrogen peroxide oxidises cerium to generate cerium oxide precipitates. Four catechins (epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate) aggregated with these precipitates to form massive precipitates with increased turbidity. The catechins solution (0.18 mL) was mixed with 0.02 mL of 1% CeCl₃ solution, and absorbance (650 nm) was measured immediately after agitation for 3 min using a spectrophotometer. Absorbance was strongly correlated (0.99) with the concentration of each catechin compound. For commercially bottled green tea, the estimated catechin content determined using this turbidimetric method showed better correlation with the content determined by high‐performance liquid chromatography than that determined using ferrous tartrate method, which is the official Japanese method for determining the tannin content of green tea.     

Simple and rapid methods for detecting Salmonella enteritidis in raw eggs

The Centers for Disease Control and Prevention estimates there were 300,000 cases of Salmonella enteritidis (SE) in 1997. Egg products were associated with many of the cases. To address this problem, many producers implemented flock surveillance of the SE situation at their facilities. A rapid and simple method for detecting SE from poultry samples is critical for the effective implementation of such testing strategies. A lateral flow device for the detection of SE utilized in this study was manufactured by Neogen, Lansing, MI. The test panel is a presumptive qualitative test system that detects only members of Group D1 Salmonella species. A series of studies were conducted to optimize the test procedure for raw eggs with different sample preparations. A novel antigen extraction method was developed for use with the test panel kit. The detection limit of the test panel kit was increased approximately tenfold when the extraction method was used. Detection of SE was 100% in raw egg pools inoculated with 10 SE cells per ml of egg and incubated at a 1:10 ratio in buffered peptone water (BPW) or tetrathionate brilliant green broth (TBG) for 24 h at 37 degrees C. The developed lateral flow test kit could provide a simple, rapid, and inexpensive method for egg producers and processors to test specifically for Salmonella group D1 serovars, such as SE, in egg samples.     

A rapid method for selectively determining small amounts of niacin,riboflavin and thiamine in foods

Niacin, riboflavin and thiamine (as thiochrome) were determined in enzymic hydrolysates of foods by high performance liquid chromatography. Paired ion chromatography, combined with ultraviolet and fluorescent spectroscopy, allowed for highly selective and sensitive detection of the vitamins.The results of the assays were similar to the more time-consuming manual methods but the accuracy and sensitivity were much higher using fluorescent detection.