Development of Bioaffinity Chromatography for Uricase Purification

The uricase inhibitors urate, xanthine, oxonate and cyanurate were tried as ligands, for preparing bioaffinity support for chromatographic separation of uricase. Only derivatised purines showed inhibitory properties, whereas derivatised s-triazines seemed to lose their absorptive capacity. Chromatographic separation on a bioaffinity support produced higher yield and better purification of Uricase than conventional chromatographic technique

Immobilised Glutamate Dehydrogenase: Possible Use In Automated Analysis.

Glutamate dehydrogenase was immobilised onto nylon tube and the activity of the enzyme tube investigated. Two different spacer molecules and two coupling techniques were utilised for immobilising the enzyme. Relatively low activity was retained on the tube, but when the enzyme tube was incorporated into a continuous flow system, and used to assay standard ammonia solution, there was adequate response for measurement. The study indicated the potential use ofimmobilised glutamate dehydrogenase in routine analytical operation

Pemerangkapan Thiobacillus denitrificans di dalam gel agaros bagi penurunan nitrate

Thiobacillus denitrificans telah diperangkap hidup-hidup ke dalam gel agaros. Keupayaan sel-sel yang terperangkap untuk menurun nitrat telah dikesan melalui keaktifan enzim nitrat reduktase. Keaktifan enzim yang tinggi telah didapati dari sel-sel yang terperangkap dan pada amnya enzim tersebut telah bertindak serupa saperti di dalam sel-sel yang bebas. Sel-sel yang terperangkap telah berupaya untuk menurun nitrat kepada nitrit apabila larutan nitrat disalurkan ke dalam reaktor berbentuk tiub yang mengandungi sel-gel

Spectrophotometric determination of benzoic acid based on inhibitive effect on tyrosinase enzyme

A simple method for detection of benzoic acid in food products has been developed based on inhibitive effect on tyrosinase enzyme. A mixture of tyrosinase, phenol and 3-methyl-2-benzothiazolinone hydrazone (MBTH) gave a maroon coloured solution which was bleached upon addition of benzoic acid. The wavelength at maximum absorbance was determined as 504 nm. The biosensor demonstrated optimum activity at pH 7. The relative standard deviation (RSD) of the reproducibility of this method was very good with RSD value of 1.91 %. The dynamic range of benzoic acid concentration was found to be between 50-700 ppm with the detection limit of 109 ppm. The kinetic parameters Michaelis-Menten constant (KM) and maximum absorbance (Absmax) in the absence and in the presence of benzoic acid were also evaluated. The kinetic analyses show that the inhibition of benzoic acid on the tyrosinase activity is reversible and competitive with an inhibition constant of 90.9 ppm. The proposed method was compared with HPLC and satisfactory agreement was achieved

‘SELF-IE’ MODULE: A COUNSELING PSYCHOLOGY INTERVENTION TO SUPPORT SELF-CHANGE AND WORK-PERFORMANCE ENHANCEMENT OF LOW-PERFORMING CIVIL SERVANTS

Purpose of the study: This study aims to examine the impact of a psychoeducational module known as the ‘SELF-IE’ module in helping low-performing civil servants. It is measured through the self-change variables of emotional stability, psycho-spirituality, and behavioral adjustment among respondents, who attended 2017 Self-Change and Well-Being Programme that used the ‘SELF-IE’ module as the intervention. Methodology: This is a quasi-experimental study, in which the impact of the ‘SELF-IE’ module was determined by measuring the mean differences of the variables for both experimental and control groups. Data were collected from a total of 68 respondents using the Personal Well-Being Questionnaire (PWQ) consisting of 60 items divided into five different sections. Main Findings: There is a significant mean difference in all three measured variables (emotional stability, psycho-spirituality, and behavioral adjustment) between both experimental and control groups, which means that the intervention using the ‘SELF-IE’ module has a positive impact in self-change of the respondents in those variables. Applications of this study: The result of this study can provide useful information to help improve any self-development program for employees’ particularly in public organizational settings. The information should be beneficial for organizational counselors or industrial psychologists, and human resources or training managers. Novelty/Originality of this study: This study specifically enhances the human assessment performance in the Public Service Department (PSD), whereby the development of the ‘SELF-IE’ module has improved the current module used in public organizations’ employee assistance program (EAP)

Analysis and classification of myocardial infarction tissue from echocardiography images based on texture analysis

Texture analysis is an important characteristic for automatic visual inspection for surface and object identification from medical images and other type of images. This paper presents an application of wavelet extension and Gray level cooccurrence matrix (GLCM) for diagnosis of myocardial infarction tissue from echocardiography images. Many of applications approach have provided good result in different fields of application, but could not implemented at all when texture samples are small dimensions caused by low quality of images. Wavelet extension procedure is used to determine the frequency bands carrying the most information about the texture by decomposition images into multiple frequency bands and to form an image approximation with higher resolution. Thus, wavelet extension procedure offers the ability to robust feature extraction in images. The gray level co-occurrence matrices are computed for each sub-band. The feature vector of testing image and other feature vector as normal image classified by Mahalanobis distance to decide whether the test image is infarction or not

A tapered fibre optics biosensor for histamine detection

Purpose: This paper aims to estimate the level of histamine in fish and fish products, as it is very important because of their implication in fish poisoning in humans; hence, ascertaining histamine levels in the aforementioned serves as a chemical index for spoilage. Design/methodology/approach: A technique was developed to immobilize an ordered multilayer of diamine oxidase (DAO) by means of chemical cross-linking on the biconical taper surface stepwisely alternating between chitosan, glutaraldehyde and the enzyme. A spectrophotometric signal results from horseradish peroxidase catalyzed reduction of H2O2, a secondary product of the oxidative deamination of histamine monitored at 450 nm. Findings: The biosensor showed a linear response range up to 1.5 mM, a good sensitivity of 0.64 mM-1 with detection and quantification limits towards histamine of 0.086 mM (15.8 ppm) and 0.204 mM (37.7 ppm) and a linear response range of 0-1.5 mM. It showed a response and recovery time of 14 sec and operational stability up to 40 repeated analyses without significant loss of sensitivity. Practical implications: The developed biosensor has a good potential for use in the quantitative determination of histamine in seafood. Originality/value: The paper described an outcome of an experimental work on tapered fibre optics (taper)-based biosensor coated with DAO embedded into a chitosan membrane to measure histamine

Purification and immobilisation of uricase for use in automated analysis

A procedure for the purification of uricase from porcine liver is described, utilising the technique of bioaffinity chromatography as a major purification step. Bioaffinity support is prepared by coupling of urate to bisoxirane-activated Sepharose 4B. Purified uricase shows a single protein band corresponding to the activity band, when applied to polyacrylamide disc-gel electrophoresis. A single protein band but no activity band is obtained by SDS-acrylamide disc-gel electrophoresis. The enzyme has a pH optimum in the range of 8.9-9.1, with a Vmax of 12.6 U.mg-1, a Km of 1 X 10-5M and a molecular weight of 13 x 104. Each enzyme molecule comprises 4 subunits of molecular weight 3 32-34 X 103 each. Nylon tube is directly activated by alkaline glutaraldehyde solution to generate reactive centres for enzyme immobilisation. The optimal conditions for activation are studied. Purified uricase is immobilised to PEI-glutaraldehyde-nylon tube with about 20% activity retention. The derivatised enzyme has a pH optimum in the range of 9.0-9.2 and a Km of about 4 times that of the soluble enzyme. Immobilised uricase is incorporated into a continuous flow Auto-Analyser for use in the automated analysis of serum urate. For this purpose, the immobilised enzyme shows good storage and operational stability. Linear calibration plots can be obtained for a urate range of 2-20 mg.100ml-1the method exhibiting a high degree of precision and accuracy. The results obtained also compare favourably with an established method of urate assay which employs soluble uricase