Development of a rapid equine serological test (REST) by modified agar-gel immunodiffusion

A rapid equine serological test (REST) has been developed for detection of horse meat in a wide variety of raw meat products. The test is an adaptation of previously developed field screening immunodiffusion tests for beef, poultry, pork, and sheep detection. Results show that the REST test was specific, sensitive, and accurate in the analysis of 101 samples.     

Development of serological ovine field test (SOFT) by modified agar-gel immunodiffusion

A serological ovine field test (SOFT) has been developed for detection of lamb or sheep tissue in a wide variety of raw meat products. The test is an adaptation of previously developed field screening immunodiffusion tests for beef, poultry, and pork detection. The SOFT test was demonstrated to be specific, sensitive, and accurate in the analysis of 104 samples.     

Development of poultry rapid overnight field identification test (PROFIT)

A poultry rapid overnight field identification test (PROFIT) has been developed as a screening test which is practical, economical, and easy to perform and interpret for use in field environments to determine the presence of poultry tissue (chicken and turkey) in raw whole tissue or ground/formulated meat products. The basis of the test is an agar-gel immunodiffusion technique used with a printed template pattern and stabilized reagent paper discs. The test shows adequate sensitivity and specificity for its intended purpose. Key components are stable for at least 1 year if they are stored at refrigerator conditions. The design of the test is such that it can be made commercially available as a complete, stable, test kit suitable for use by any type of inspection program concerned with verification of poultry species in meat and/or poultry products that are subject to regulatory or quality controls.     

蔬菜废弃物快速堆肥方法研究

对蔬菜废弃物快速堆肥化利用方法进行了比较。试验设置了地下厌氧、地下好氧、地上厌氧和地上好氧4个处理,并对各处理的理化指标进行观测比较。结果表明,好氧处理较厌氧处理温度上升快,持续时间长,肥料含水率下降快,腐熟程度好;其中地上好氧处理最高堆温达52℃,高温期能够保持10 d,有机质、全氮、速效磷、速效钾含量也最高,分别达25.01 g/kg、11.00 g/kg、72.92 mg/kg和749.16 mg/kg,是一种较好的蔬菜废弃物快速堆肥方法。     

Development of a screening method for genetically modified soybean by plasmid-based quantitative competitive polymerase chain reaction

A novel type of quantitative competitive polymerase chain reaction (QC-PCR) system for the detection and quantification of the Roundup Ready soybean (RRS) was developed. This system was designed based on the advantage of a fully validated real-time PCR method used for the quantification of RRS in Japan. A plasmid was constructed as a competitor plasmid for the detection and quantification of genetically modified soy, RRS. The plasmid contained the construct-specific sequence of RRS and the taxon-specific sequence of lectin1 (Le1), and both had 21 bp oligonucleotide insertion in the sequences. The plasmid DNA was used as a reference molecule instead of ground seeds, which enabled us to precisely and stably adjust the copy number of targets. The present study demonstrated that the novel plasmid-based QC-PCR method could be a simple and feasible alternative to the real-time PCR method used for the quantification of genetically modified organism contents.     

Development of a sensitive and rapid method for the measurement of total microbial activity using fluorescein diacetate (FDA) in a range of soils

Fluorescein diacetate (FDA) hydrolysis is widely accepted as an accurate and simple method for measuring total microbial activity in a range of environmental samples, including soils. Colourless fluorescein diacetate is hydrolysed by both free and membrane bound enzymes, releasing a coloured end product fluorescein which can be measured by spectrophotometry. The current method for measuring FDA hydrolysis in soils is limited in its application. FDA activity was very low in sandy and clayey soils. The low activity observed for these soil types was made difficult to measure by the original authors’ choice of solvent for terminating the hydrolysis reaction. Acetone (50% v/v) was found to be most efficient at stopping the hydrolysis reaction. During this study acetone (50% v/v) was found to cause a decrease of approximately 37% in the absorbance of fluorescein produced by the soil samples measured. Although this colour loss is independent of initial fluorescein concentration, it makes the measurement of FDA hydrolytic activity extremely difficult in soils with low microbial activity i.e. sandy and/or clayey soils. Chloroform/methanol (2:1 v/v) was found to successfully stop the hydrolysis reaction for up to 50 min in a range of soil samples without causing the loss of colour observed with acetone. By changing the solvent used for terminating the hydrolysis reaction, low activity soils could be measured successfully. Other parameters of the hydrolysis reaction were optimised for the measurement of soil samples including effect of pH, optimum temperature of incubation, amount of soil, time of incubation, amount of substrate and preparation of suitable standards. A new, more sensitive method is proposed adapted from the original method, which provides a more accurate determination of FDA hydrolysis in a wide range of soils.     

Modified method for rapid quantitation of S-alk(en)yl-L-cysteine sulfoxide in yellow onions (Allium cepa L.)

In this study, a rapid and sensitive method to determine the flavor precursors was established on the basis of modified Kubec's gas chromatography (GC) method. For the new method, the interference of halogen was removed by adding borohydride that replaced halide as a reducing reagent, and the analysis was completed within 25 min for the determination of S-alk(en)yl-L-cysteine sulfoxides (ACSOs). In comparison with the results of high-performance liquid chromatography (HPLC), the modified GC method is much better in the separation and detection of ACSOs in yellow onion bulbs than the original method. A small amount of 2-propenyl-L-cysteine sulfoxides (2-PeCSO) was detected with the modified GC method, and propyl-L-cysteine sulfoxides (PrCSO) were not detected. The results of GC determination indicated that 2-PeCSO probably was the hydrolysate of a byproduct or an isomer of gamma-glumtyl-1-propenyl-L-cysteine sulfoxides in biosynthesis process.     

基于介电特征频率的大量元素水溶肥种类快速辨识装置研制

为实现对大量元素水溶肥种类的快速准确辨识,根据水溶肥的介电特性设计了一个传感器,并在此基础上采用特征频率法,研制了一种大量元素水溶肥快速辨识装置,主要由±5V稳压电路、单片机控制电路、激励信号发生电路、传感器、真有效值转换电路和LCD显示模块组成。以市面上常见的尿素、普钙、硫酸钾、磷酸氢二铵、磷酸二氢钾和硝酸钾6种大量元素水溶肥作为试验对象,在1 kHz~10 MHz激励信号频率范围内研究了其频率响应特性,得出了9个用于辨识6种大量元素水溶肥的激励信号特征频率,即30、40、50、600、700、800 kHz和3、4、5 MHz。根据各种水溶肥分别在9个特征频率处的响应模式,设计了对6种大量元素水溶肥的辨识策略。该装置的辨识性能采用234组不同类型和浓度的待测水溶肥进行验证试验,结果表明:该装置的辨识准确率为98.3%,完成1次辨识的平均时间为14.3s,最长不超过19.5 s,表明该装置具有良好的快速性和准确性,满足实际应用要求。     

Development of a rapid titration method for predicting optimal coagulant concentration for filled tofu

A rapid titration method was developed for predicting the optimal coagulant concentration for making filled tofu. Cooked soymilk (350 mL, 20 degrees C) in a 400 mL beaker was stirred by a magnetic stirrer to form a swirl. The quick-acting coagulant solution (20.0 Brix) was added into the soymilk at 1.0 mL/min. The swirl depth decreased when the soymilk viscosity increased as a result of increasing the concentration of coagulant in the soymilk. At a suitable stirrer speed, the swirl finally disappeared but the soymilk still maintained rotation, and then the swirl reappeared after around 1 min. The critical point of coagulant concentration (CPCC) was calculated on the basis of the volume of coagulant consumed to get the swirl to disappear. The influences of several factors on the CPCC were investigated, including coagulant addition rate, soymilk temperature, soymilk concentration, soymilk volume, stir bar length, and container size. For validation, 33 soybean samples were used to determine their CPCCs and make filled tofus. The results indicated that CPCC was a characteristic parameter of soymilk and could be used as an effective indicator for predicting optimal coagulant concentration.     

应用PCR技术鉴定绵羊胎儿成纤维细胞系性别

根据牛、羊Y－染色体性别决定区域（SRY）的同源性设计了一对PCR引物，对8个绵羊胎儿成纤维细胞系SFF1－8进行了性别鉴定。阳性对照和细胞系SFF1、2、6、7扩增得到130bp片段，阴性对照、空白对照及细胞系SFF3、4、5、8没有扩增带。通过序列测定和同源性分析，证明PCR产物为SRY基因片段，说明有130bp扩增带的细胞系为雄性；无扩增带的为雄性。结果表明，该法具有简单、快速、准确的特点，可应用于转基因克隆动物研究中对体细胞系的早期性别鉴定。     

土壤速效氮、磷、钾速测方法的改进Ⅰ.新速测方法的建立

本文对国内现行土壤速效养分速测方法进行了改进 ,包括 :饱和浸提液的制备、浸提剂的筛选、测定方法的改进等 .实验结果表明 :新方法与代表性土壤速效养分速测方法比较 ,提高了精度 ,省时 ,成本低 ,适合于基层土肥站和肥料厂开展测土施肥工作 .     

应用改进的平板检测法快速筛选解钾菌

The utility of microorganisms for solubilizing the unavailable forms of potassium(K) from soil has led to renewed interest in fabrication of rapid and sensitive plate assays for their isolation and screening. The present study developed a modified plate assay and compared it with previously reported methods for the isolation and screening of K-solubilizing bacteria. The newly developed plate assay is based on improved visualization of halo zone formation around the colonies on agar plates, through inclusion of an acid-base indicator dye, bromothymol blue(BTB), to modify the previously reported Aleksandrov medium. The halo zone exhibited a significant correlation(R = 0.939) with K released in liquid medium. The visualization of potential K solubilizers was improved using this method, which would help in detection of weak/non-acid producers based on secretion of organic acids in the medium. Organic acids in plate diffuse radially and form halo zones in response to reaction with the acid-base indicator dye BTB. Furthermore, K solubilization on plates with this method can be observed within 48–72 h, against the incubation time of 4–5 d needed in the earlier method. Therefore, the newly developed protocol for the plate assay was time saving, more sensitive, and beneficial in comparison to the previously reported Aleksandrov plate assay.     

磁电辅助快速腌制咸鸭蛋的工艺

为了实现咸蛋的快速腌制,采用磁电辅助的方法对鸭蛋进行处理,考察了不同体系场强（1～3 V/cm）、电场频率（50～200 Hz）、磁场强度（0.026～0.13 T）和磁场频率（1～5 Hz）对鸭蛋盐分和出油率的影响,结果表明：在试验条件范围内,体系电压和磁场强度越高则利于样品获得更高的盐分和出油率,在体系电压3 V/cm,磁场强度0.09 T时腌制效果较佳,腌制时交变电场和旋转磁场的较适频率值分别为100和5 Hz,蛋清、蛋黄盐分最高各自为5.73%和0.79%,蛋黄出油率则可达17.84%,较常规腌制和真空腌制有显著提高（P<0.05）,具体表现为（7 d时）：相对于常规腌制和真空腌制对照样,蛋清盐分质量分别为其4.9倍和1.2倍,而蛋黄盐分质量分数则分别为其3.1倍和1.3倍,蛋黄出油率分别提高了2.3倍和0.5倍,研究结果为咸蛋的快速腌制提供了一种新的参考方法。     

Detection of soluble Rhizobium japonicum antigens in soil by immunodiffusion

Innovative techniques for quantifying rhizobia in soil are needed. Immunodiffusion was adapted for use in evaluating four strains of Rhizobium japonicum incubated in soil. Reproducible precipitin bands were obtained using uniform soil cores 5 mm dia × 4 mm length collected with a cork borer. A flocculent of Ca(OH)₂ and MgCO₃ added to the microcores enhanced band formation. Clear distinct bands developed from populations in soil of 1 × 10⁸ cells g^?1 or greater. The complete set of bands which characterized cells cultured on artificial media did not develop from cells inoculated into soil, but at least one detectable band was always observed. Parameters of intensity value and band positioning were related to the population in the soil. Detection by immunodiffusion of a series of rhizobial populations in soil decreased with time almost linearly as the initial population decreased. Direct diffusion of antigens from soil and the development of specific precipitin bands provides a new approach to studying soil microorganisms.     

折光率法在包膜尿素养分释放快速测定中的校验与改进

以不同肥效期的15个自制包膜尿素为检测样品,以肥水质量比为1/5的恒温静水溶出法为控释尿素的培养方法,同时采用常规方法和工作曲线折光率法测定培养液中的尿素含量,并对养分释放曲线进行Richards 方程的非线性回归分析用以计算样品的肥效期,对比研究现配工作曲线折光率法与同期培养工作曲线法同常规方法测定结果之间的异同,以期为控释尿素养分释放测定提供更准确的快速测定方法。研究结果表明：系列标准尿素溶液分别培养0、1、6、7、14、21、28和56 d后,其折光率与浓度之间的关系均可用直线方程表示(决定系数≥0.998),其中同期培养曲线的预测误差为0.34～1.13 g/L,而现配曲线的预测误差为0.71～4.85 g/L,采用尿素标准溶液工作曲线检测同等培养期的尿素溶液有利于提高测定结果的准确性。与H2SO4消煮法（常规方法）相比,采用新鲜工作曲线折光率法测定控释尿素养分释放的计算结果提高10%以上,采用标准尿素溶液与包膜尿素同期培养的方法,折光率法测定结果与常规方法之间的系数为0.990。为进一步分析折光率法检测包膜尿素肥效期准确性,采用Richards方程模拟2种方法所测的释放曲线并计算养分达到75%的时间点即肥效期,结果表明,常规方法和折光率法测得15个包膜尿素的肥效期为21.9～245.9和22.0～210.1 d,两者相差最小值和最大值分别为0.2和41.4 d,相对偏差则分别为0.8%和25.1%。其中肥效期较短的包膜尿素的测定偏差较小,肥效期较长尤其是达到180 d以上的包膜尿素可能由于后期释放过于缓慢导致预算误差扩大,其误差区间为27.6～40.4 d,这属于可接受范围。说明了同期培养工作曲线折光率法可以作为常温条件下的控释尿素养分释放的速测方法,并可利用模型较准确地预测包膜尿素的肥效期。研究结果可为包膜尿素养分释放率及肥效期的快速、准确测定提供参考。     

Evaluation method of feature vector in vinegar identification by electronic nose

电子鼻检测中常用的特征鉴别能力评价方法有2种,一是对判别结果的直观分析,二是对判别正确率的统计计算。但是,当判别正确率相同时,对于不同特征间鉴别能力的差异,2种方法都不能进行准确的定量评价。为实现特征鉴别能力的准确度量,以不同种类食醋为检测对象,对检测信号提取面积斜率比、方差、积分、平均微分值、相对稳态平均值、小波能量等6种特征参量,并将特征参量与类别间的相关系数作为特征鉴别能力的度量指标。计算结果可知：面积斜率比特征参量的相关系数绝对值最小,为0.1027,积分特征参量的相关系数绝对值最大,为0.6455。表明面积斜率比特征参量的鉴别能力最低,积分特征参量的鉴别能力最高。Fisher判别结果也证明了特征参量的鉴别能力越高,其分类效果越好。因此,用特征参量与类别间的相关系数作为特征鉴别能力的度量是合适的、也是有效的。     

食醋电子鼻检测中一种特征参量评价方法

电子鼻检测中常用的特征鉴别能力评价方法有2种,一是对判别结果的直观分析,二是对判别正确率的统计计算。但是,当判别正确率相同时,对于不同特征间鉴别能力的差异,2种方法都不能进行准确的定量评价。为实现特征鉴别能力的准确度量,以不同种类食醋为检测对象,对检测信号提取面积斜率比、方差、积分、平均微分值、相对稳态平均值、小波能量等6种特征参量,并将特征参量与类别间的相关系数作为特征鉴别能力的度量指标。计算结果可知:面积斜率比特征参量的相关系数绝对值最小,为0.1027,积分特征参量的相关系数绝对值最大,为0.6455。表明面积斜率比特征参量的鉴别能力最低,积分特征参量的鉴别能力最高。Fisher判别结果也证明了特征参量的鉴别能力越高,其分类效果越好。因此,用特征参量与类别间的相关系数作为特征鉴别能力的度量是合适的、也是有效的。     

1H NMR, a rapid method to monitor organic acids during cupuassu (Theobroma grandiflorum Spreng) processing

The development of an analytical method using 1H nuclear magnetic resonance (1H NMR) spectrometry to monitor cupuassu (Theobroma grandiflorum Spreng) bean fermentation, drying, and roasting processes is reported. The analysis of organic acids and alcohols of crude water extracts of cupuassu ground kernels were monitored by HPLC and 1H NMR spectroscopy. The residual protein signals caused deleterious effects on acid and alcohol quantifications. Therefore, the analytical procedures were optimized by sample cleanup and water suppression pulse sequences in order to obtain compatible data using HPLC and 1H NMR. The quantification of lactic acid, acetic acid, and 2,3-butanediol by NMR is 5- to 10-fold faster than by HPLC, with the advantage of providing the identification of several chemical species in a single experiment. Application of these analytical conditions to some cupuassu samples revealed that this methodology can be applied to the quality profiles of fermentation and roasting processes.