Protein Profiling of Several Malaysian Freshwater Fish by Two-Dimensional Electrophoresis

A proteornics approach using 2D-PAGE was initiated to investigate protein expression in fish organs especially hepatopancreas, with the aim of providing fish protein expression maps that are seriously lacking in the literature. Two dimensional electrophoresis maps of hepatopancreas from Jelawat (Leptobarbus hoevenii), Catfish (Clarias batrachus), Red tilapia (Oreochromis mossambicus), Patin (Pangasius pangasius) and Lampam Jawa (Puntius gonionotus); all Malaysian freshwater fish species were constructed. The soluble protein sample was analyzed by two dimensional electrophoresis, using immobilized pH gradient strip (pH 3-10) and 15% gel acrylamide. 200 protein spots from Red Tilapia and 44 spots from Catfish were observed. Compari sons of similarities in terms of protein spots in the fish species were made using ruler measurements and superimposing the electropherogram of one fish species with the other to confirm spots coordinate similarities. The maximum matching found in terms of pI and molecular weight coordinate is limited to a maximum of three fish species. Patin-Lampam Jawa-Jelawat and Lampam Jawa-Red tilapia-Jelawat share the most number of spots at 8 spots. At the two-fish comparison level, the highest number of same spots was found in Red tilapia-Jelawat (33 spots) followed by Lampam Jawa-Jelawat (25 spots), Lampam Jawa-Red tilapia (20 spots), Patin-Lampam Jawa (17 spots), Patin-Red tilapia, Patin- Jelawat and Lampam Jawa-Catfish; all with 12 same spots

The impact of the key audit matters (KAMS) disclosures on investor’s decision making / Norazura Masdor and Amanuddin Shamsuddin

In 2015, Malaysia implemented the ISA701 - Communicating Key Audit Matters (KAMs) in the Independent Auditor’s Report to the Malaysian Public Listed Companies (PLCs). The Standard was first observed for audits of financial statements for financial periods ending on or after Dec 15, 2016. Thus, this paper examined the impact of KAMs disclosure on investors’ decision-making. This study explored whether this new requirement is associated with an increase in the investors’ decision usefulness based on the auditor’s report. This study employed critical content analysis on the samples that consisted of 337 PLCs in Bursa Malaysia for the year ended December 2016. Share prices were used as dependent variables to represent investors’ responsiveness when KAMs disclosed in audit reports. The share prices cover three periods of analysis; average seven days before event date (audit report date), at event date, and average seven days after event date. Independent variables include KAMs and control variables are profitability, leverage and size. Findings from the study suggest that the mandating of KAM’s disclosure has no informational value to the investors of Malaysian PLCs. Nevertheless, the paper did not offer a comprehensive analysis of KAMs issues; rather it focused on the impact of KAMs disclosure on investors’ reaction on the first year of implementation. However, the paper encourages reflections on contemporary practices and offers some suggestions for reform in the near future

Near real-time biomonitoring of copper from an industrial complex effluent discharge site using a plant protease inhibitive assay

In this work, a temporal monitoring work for heavy metals from an effluent discharge point in the Juru Industrial Estate was carried out using the protease extracted from garlic (Allium sativum) as the principal bioassay system. Casein-Coomassie-dye binding assay method has utilized this purpose. The periodic sampling results for one day of a location in the Juru Industrial Estate showed temporal variation of copper concentration coinciding with garlic protease inhibition with the highest concentrations of copper occurring between 12.00 and 16.00 hours of between 3 and 3.5 mg/L copper. The crude proteases extracted from Allium sativum successfully detect temporal variation of copper form this location. In conclusion, this assay method has the potential to be a rapid, sensitive, and economic inhibitive assay for the large-scale biomonitoring works for the heavy metal copper from this area

Preliminary screening of plant proteases as a potential source for the development of an inhibitive assay for heavy metals

Heavy metals pollution has become a great threat to the world. Since instrumental methods are expensive and need skilled technician, a simple and fast method is needed to determine the presence of heavy metals in the environment. In this work, a preliminary study was carried out on the applicability of various local plants as a source of protease for the future development of the inhibitive enzyme assay for heavy-metals. The crude proteases preparation was assayed using casein as a substrate in conjunction with the Coomassie dye-binding assay. The crude protease from the kesinai plant was found to be the most potent plant protease. The crude enzyme exhibited broad temperature and pH ranges for activity and will be developed in the future as a potential inhibitive assay for heavy metals

Testing the normality of residuals on regression model for the growth of Moraxella sp. B on monobromoacetic acid

Bioremediation of monobromoacetic acid, a haloacetic acid, continues to be recommended as a cheaper and achievable method in comparison to physical and chemical techniques. In a prior work, we model the growth of the bacterium Moraxella sp. B on monobromoacetic acid from published literature to acquire crucial growth constants. We learned that the Buchanan-three-phase model via nonlinear regression using the least square method was the most effective model to describe the growth curve. Nevertheless, the use of statistical tests to choose the best model relies heavily on the residuals of the curve to be statistically robust. More often than not, the residuals must be tested for conformation to normal distribution. In order for these assumptions to be met, we perform statistical diagnosis tests such as the Kolmogorov-Smirnov, Wilks-Shapiro and D'agostino-Pearson tests

Near-real-time Biomonitoring of Heavy Metals Using the Xenoassay® System

Heavy metals have widespread industrial uses and have been found in increasing quantities as contaminants in all components of the biosphere. Water and sediment of rivers near industrial areas such as the Juru River in Penang and Langat River in Selangor are polluted with heavy metals. Thus, rapid and fast methods to detect the presence of heavy metals in the environment are necessary. Existing instrumental methods such as atomic absorption and emission spectrometry are very sensitive but the sole use of these instruments for heavy metal detection is extremely expensive, needs a skillful person to operate and is not amenable to near-real-time analysis. The best scenario for routine biomonitoring of heavy metals is the marriage between instrument- and bioassays. Currently, the USEPA has recognized whole cell-based bioassays such as as PolytoxTM and Microtox® for the detection of heavy metals. Unfortunately these cell-based assays cannot be used as real-time or near real-time assays in the field as they require bulky incubators. Near-real-time monitoring of heavy metals giving results in less than one hour is very useful in environmental CSI (Criminal Scene Investigation) or ECSI where temporal and spatial concentrations of heavy metals in running waters are a challenge to environmentalists to pinpoint heavy metals POS (point of source) for legal purposes. Enzyme-based inhibitive assays are simple, rapid and fast and could be developed for near real-time assays. We have developed an inhibitive assay system –Xenoassay® based on proteases for the assay of heavy metals. The system could detect the heavy metals mercury, cadmium, lead, copper, zinc and silver at the sub parts per million level. Field trial near-real-time assay capability shows promising results

The development of an inhibitive determination method for zinc using a serine protease

A new inhibitive heavy metals determination method using trypsin has been developed. The enzyme was assayed using the casein-Coomassie-dye-binding method. In the absence of inhibitors, casein was hydrolysed to completion and the Coomassie-dye was unable to stain the protein and the solution became brown. In the presence of metals, the hydrolysis of casein was inhibited and the solution remained blue. The bioassay was able to detect zinc and mercury with IC50 (concentration causing 50% inhibition) values of 5.78 and 16.38 mg l-1 respectively.The limits of detection (LOD), for zinc and mercury were 0.06 mg l-1 (0.05-0.07, 95% confidence interval) and 1.06 mg l-1 (1.017-1.102, 95% confidence interval), respectively. The limits of quantitation (LOQ) for zinc and mercury were 0.61 mgl-1 (0.51-0.74 at a 95% confidence interval)and 1.35 mg l-1 (1.29-1.40 at a 95% confidence interval), respectively. The IC50 value for zinc was much higher than the IC50 values for papain and Rainbow trout, but was within the range of Daphnia magna and MicrotoxTM. The IC50 value for zinc was only lower than those for immobilized urease. Other toxic heavy metals, such as lead, silver, arsenic, copper and cadmium, did not inhibit the enzyme at 20 mg l-1. Using this assay,we managed to detect elevated zinc concentrations in several environmental samples. Pesticides, such as carbaryl, flucythrinate, metolachlor, glyphosate, diuron, diazinon, endosulfan sulphate, atrazine, coumaphos, imidacloprid, dicamba and paraquat, showed no effect on the activity of trypsin relative to control (One-way ANOVA, F12, 26 = 0.3527, p> 0.05). Of the 17 xenobiotics tested, only (sodium dodecyl sulphate) SDS gave positive interference with 150 % activity higher than that of the control at 0.25% (v/v)

An inhibitive determination method for heavy metals using bromelain, a cysteine protease

A heavy-metal assay has been developed using bromelain, a protease. The enzyme is assayed using casein as a substrate with Coomassie dye to track completion of hydrolysis of casein. In the absence of inhibitors, casein is hydrolysed to completion, and the solution is brown. In the presence of metal ions such as Hg2+ and Cu2+, the hydrolysis of casein is inhibited, and the solution remains blue. Exclusion of sulfhydryl protective agent and ethylenediaminetetraacetic in the original assay improved sensitivity to heavy metals several fold. The assay is sensitive to Hg2+ and Cu2+, exhibiting a dose-response curve with an IC50 of 0.15 mg 1(-1) for Hg2+ and a one-phase binding curve with an IC50 of 0.23 mg 1(-1) for Cu2+. The IC50 value for Hg2+ is found to be lower to several other assays such as immobilized urease and papain assay, whilst the IC50 value for Cu2+ is lower than immobilized urease, 15-min Microtox, and rainbow trout

Isolation and characterization of a molybdenum-reducing and amide-degrading Burkholderia sp. strain NENI-11 in soils from West Sumatra, Indonesia

A molybdenum-reducing bacterium isolated from contaminated soil was able to utilize acrylamide as the electron donor source, and was able utilize acrylamide, acetamide and propionamide for growth. Reduction was optimal at pH between 6.0 to 6.3, at temperatures of between 30 and 37 oC, glucose as the electron donor, phosphate at 5.0 mM, and sodium molybdate at 15 mM. The absorption spectrum of the Mo-blue indicates it is a reduced phosphomolybdate. Molybdenum reduction was inhibited by mercury (ii), silver (i) and chromium (vi) at 2 p.p.m. by 91.9, 82.7 and 17.4 %, respectively. Biochemical analysis resulted in a tentative identification of the bacterium as Burkholderia cepacia strain Neni-11. The growth of this bacterium modelled according to the modified Gompertz model. The growth parameters obtained were maximum specific growth rates of 1.241 d-1, 0.971 d-1, 0.85 d-1 for acrylamide, propionamide and acetamide, respectively, while the lag periods of 1.372 d, 1.562 and 1.639 d were observed for acrylamide, propionamide and acetamide, respectively. The ability of this bacterium to detoxify molybdenum and grown on toxic amides makes this bacterium an important tool for bioremediation