This review paper briefly explains the meaning and characteristics of endocrine disrupting compounds (EDCs). EDCs comprise various types of natural and synthetic chemical compounds that can impede the reproductive action of the endocrine system in animals and humans. Further discussion is on bisphenol A (BPA), one of the examples of EDCs that is extensively used in industries nowadays. It acts as a monomer, which is desired in the production of polycarbonate plastics and epoxy resins. BPA later ends up in environmental compartments (air, water, sediment). In spite of this, BPA is not categorized as a persistent compound and it will be degraded either by photolysis or bacteria. It can only exist between three and five days in the environment. The concentration of BPA varies in different locations depending on the temperature, pH, source and time of sampling. BPA has been frequently debated due to its toxicity and carcinogenicity towards animals and humans. This paper also explains several extraction procedures and analytical methods concerning how to identify BPA in either aqueous or solid samples. However, an additional review is needed in respect of how to handle, reduce the level of BPA in the environment and understand the details concerning the existence of BPA.
In this study, the substrate specificity and the inhibition kinetics of various types of insecticides to the acetylcholinesterase (AChE) from a local fish; Puntius schwanenfeldii were investigated. The substrate specificity determination was done using three thiocholine substrates, which were ATC, PTC and BTC. The results showed that he partially purified cholinesterase from Puntius schwanenfeldii that preferred ATC is a true AChE. The Km and Vmax values of AChE for these substrates were 16.61 mmol and 286.5 U/mg for ATC, 19.92 mmol and 245.3 U/mg for PTC, and 48.64 mmol and 219.6 U/mg for BTC, respectively. The IC50 values for the carbamates bendiocarb, carbaryl, propoxur, carbofuran and methomyl were 0.838, 7.045, 29.441, 1.411 and 8.335 mg/L, respectively, which were comparable to the IC50 values for carbamates from several AChE from fish.
The Malacca river runs through the Malacca UNESCO heritage site where a number of historical buildings are located. The river itself runs through several industrial sites that increase the chances of the water being polluted. Water pollution including heavy metals, in the long run, can damage the reputation of the site. Hence monitoring of the water quality needs to be done periodically. As the cost of instrumental monitoring is costly, biomonitoring using enzyme is being intensely developed worldwide. In this study, a rapid inhibitive enzyme assay using the molybdenum-reducing enzyme from the bacterium Serratia sp. strain DRY6 sensitive to the heavy metals mercury, copper, silver, and chromium was developed as a method for a rapid monitoring of heavy metals. The IC¬50 values for mercury, copper, silver and chromium were 0.268, 0.352, 0.393 and 0.499 mg L-1, while the LOD values were 0.166, 0.071, 0.033 and 0.064 mg L-1, respectively. The IC50 values for these heavy metals are comparable and in several cases, more sensitive than established assays. Water samples from various locations in the Melaka river were tested for the presence of heavy metals using the developed assay. Enzyme activity was found to be inhibited in one sampling location, but the concentration of metal ions on the site was found to be below the Maximum Permissible Limit according to Malaysian Environmental Quality standard. The assay for heavy metals can be completed in less than 10 minutes and can be carried out at ambient temperature. The assay is rapid and simple and can be used as a first screening method or even near real-time method for routine monitoring of heavy metals.
Human activities in a large array of industrial and agricultural sectors produce chemical contaminants which are chiefly hydrocarbons of various types that are potentially toxic and carcinogenic to aquatic and terrestrial organisms. Globally, millions of tons of these pollutants are generated annually, and in some areas, they are released indiscriminately to the environment. In order to overcome this problem, microbiological decontamination or bioremediation has been suggested. Bioremediation has been argued to be an efficient, economic, and adaptable alternative to physicochemical remediation. However, to date, such claims of successful bioremediation are often not supported by evidence from toxicity studies. In this regard, luminescent bacteria have been employed in some hydrocarbon remediation experiments to denote reduction in toxicity. In this review, the utilization of luminescence bacteria as toxicity monitoring agent for hydrocarbon remediation is discussed.
Acrylamide is a monomer to polyacrylamide; a polymer with diverse application in basic research, industries and agriculture. The monomer is highly toxic while the polymeric form is slowly degraded to its monomeric form in the environment. In this mini review, the toxicity, uses, pollution and biodegradation of this important monomer are discussed. An important aspect of this review is to highlight the application of microorganisms as remediating agent for the removal of this compound from the environment.
The mistletoe fig (Ficus deltoidea) is frequently found in several areas of the world, and primarily functions as houseplant or an ornamental shrub. The plant is discovered indigenous generally in Asia tropical region for example Indonesia, Philippines, Malaysia, and Thailand. Scientific studies on the effect of plant growth regulators on cells production from this plant are vital as optimization of cells production may result in effective production of secondary products characterization and output. The growth of cell suspension cultures from this plant shows sigmoidal property. In this work, we model the effect of the plant growth regulator 2,4-dichlorophenoxyacetic acid (2,4-D) on the growth kinetics of the cells from this plant according to the modified Gompertz model. The coefficient of determination showed good agreement between experimental and predicted data with values ranging from 0.97-0.98. The results showed that 2,4-D at 2 mg/L was optimal for achieving the highest cells growth rate. It is anticipated that the growth parameter constants extracted from the modelling exercise will be helpful in the future for additional secondary modelling on the effect of media conditions as well as other factors on cells growth.
Chikungunya is an acute febrile illness caused by chikungunya virus (CHIKV). In this study, the envelope E1 gene of CHIKV was cloned and expressed in a baculovirus system. The recombinant E1 protein with N-term 6-His residues protein was successfully expressed and purified as confirmed by SDS-PAGE and western blot analysis. The seroreactivity of the recombinant protein was evaluated in immunoassay for anti-CHIKV IgM and IgG antibodies. The recombinant antigen showed 69% sensitivity and 100% specificity for anti-CHIKV IgG by dot blot assay. Detection of anti-CHIKV IgM by dot assay showed 79% sensitivity and 100% specificity. No cross reactivity of the antigen was observed with anti-dengue virus serum samples. The results strongly support that the recombinant E1 protein has potential to be used as diagnostic antigen. The used of the antigen in a dot blot assay gives an advantage for laboratory detection without the need of any specialised equipment.
Monoclonal antibodies (mAbs) are unique and specific drug molecules targeting the treatment of various diseases such as arthritis, immune disorders, infectious diseases, and cancer etc. Different methods such as antibody coupled affinity chromatography, hydrophobic interaction chromatography, etc., can be applied to purify mAbs from various sources. This article provides a simple, cost effective, preparative native-polyacrylamide gel electrophoresis (n-PAGE)technique to purify mAbs expressed in H-192 cells (Hybridoma murine cell lines) against an antigen i.e. 17-alpha-hydroxyprogesterone (17-OHP), which further can have diagnostic application to detect Congenital Adrenal Hyperplasia (CAH). Furthermore, different parameters such as concentration and volume of the feedstock (medium containing antibodies), pore size of gel, height of resolving gel etc. were optimized to obtain the maximum purity and yield of mAbs.
MeSH terms: Adrenal Hyperplasia, Congenital; Animals; Antibodies, Monoclonal; Arthritis; Cell Line; Chromatography, Affinity; Hybridomas; Immune System Diseases; Neoplasms; 17-alpha-Hydroxyprogesterone; Mice; Hydrophobic and Hydrophilic Interactions; Native Polyacrylamide Gel Electrophoresis
Palm kernel cake (PKC), a by-product of the palm oil industry is limited in its use as a feed ingredient for poultry due to its high fibre and lignin content. The presence of these antinutritive components is the result of shells contaminating the by-product. The nutritive value of PKC has to be improved in order to increase its inclusion rate in poultry diet. In this study, PKC was subjected to a separation method using static cling and electrostatic separation to removethe shells present in PKC. Response surface methodology based on Box-Behnken design was used to optimize the separation method with moisture content (8 to 18%), particle size distribution (0.5 to 2.5 mm) and feed rate (20 to 200 g/min) as the independent variables evaluated. According to the regression coefficients and significance of the quadratic polynomial model, the optimum separation parameters were as follows: 13% PKC moisture content;
In response to the globalization of drug development, regulatory inspection of Good Clinical Practice (GCP) has recently been conducted not only by International Conference on Harmonisation (ICH) regions but also non-ICH regions. To promote the international implementation of GCP, consistent understanding and interpretation of its concept among regions are important. This article summarizes the background and past activities of the E6 Discussion Group, established under the Regulators Forum.
MeSH terms: United States; United States Food and Drug Administration; Internationality
Investigation on in vivo effects of copper (Cu) on the ultrastructure of P. javanicus liver was
carried out using transmission electron microscopy (TEM). The addition of sublethal
concentration of 5 mg/L of Cu caused abnormalities on the bile canaliculi (BC) including
dilation and elongation compared to control and at lower concentrations of copper with a normal
round shape form. Findings from this study support an alternative histological assessment of the
effects of Cu concentration on P. javanicus liver.
MeSH terms: Bile Canaliculi; Copper; Dilatation; Liver; Microscopy, Electron, Transmission
Observations on the effects of copper on the liver proteome of Puntius javanicus based on the
one dimensional PAGE was carried out. The liver was dissected from each fish, which was
separately treated with different concentrations of copper sulfate ranging from 0.1 to 5.0 mg/L.
The livers were extracted and one dimensional PAGE was performed under nonreducing
(native) and reducing (SDS)-PAGE. Several bands were resolved in the native PAGE with
probable candidates for the effect of copper observed showing an increased in the expression
and downregulation strongly associated with increasing copper concentrations. This study
showed that high concentrations of copper significantly alters P. javanicus liver at the proteome
level, and preliminary screening based on one dimensional PAGE is considered rapid and
simple to assess the toxicity effect of copper before more advanced and extensive assesment
with a second dimensional PAGE is carried out.
The 3D structure of the insecticidal protein Cry1Ba4 produced by B. thuringiensis subsp.
Entomocidus HD-9 was determined using homology modelling. From the model built, we have
been able to identify the possible sites for structure modification by site-directed mutagenesis.
The mutation was introduced at the conserved region of -helix 7 by substituting the
hydrophobic motif that comprises alanine 216, leucine 217 and phenylalanine 218 with arginine.
Wild and mutant Cry1Ba4 genes were cloned into pET200/D-TOPO and expressed in the
expression host. The result suggests that mutant Cry1Ba4 protein was less toxic to the larvae
Plutella xylostella compared to the wild-type. In conclusion, alteration in the structure of
Domain I had left an impact on the toxicity of Cry1Ba4 against P. xylostella.
Chemical toxins and organic contaminants such as hydrocarbons and dyes are major global
contaminants with countless tones of those chemicals are created yearly with a significant
amount release to the environment. In this work we screen the ability of a molybdenum-reducing
bacterium isolated from contaminated soil to decolorize various azo and triphenyl methane dyes
independent of molybdenum reduction. Biochemical analysis resulted in a tentative identification
of the bacterium as Enterobacter sp. strain Zeid-6. The bacterium was able to decolorize the azo
dye Orange G. The bacterium reduces molybdate to Mo-blue optimally at pH between 5.5 and
8.0 and temperatures of between 30 and 37 oC. Other requirements include a phosphate
concentration of 5 mM and a molybdate concentration of 20 mM. The absorption spectrum of the
Mo-blue produced was similar to previous Mo-reducing bacterium, and closely resembles a
reduced phosphomolybdate. Molybdenum reduction was inhibited by copper, lead, mercury and
silver which showed 36.8, 16.9, 64.9 and 67.6% inhibition to Mo-reducing activity of
Enterobacter sp. strain Zeid-6, respectively. The resultant molybdenum blue spectrum closely
resembles the spectrum of molybdenum blue from the phosphate determination method. The
ability of this bacterium to detoxify molybdenum and decolorize azo dye makes this bacterium
an important tool for bioremediation.
The volume of contaminated rivers in Malaysia continues to keep rising through the years. The
cost of instrumental monitoring is uneconomical and prohibits schedule monitoring of
contaminants particularly heavy metals. In this work, a rapid enzyme assay utilizing the
molybdenum-reducing enzyme as an inhibitive assay, prepared in crude form from the
molybdenum-reducing bacterium Serratia sp. strain DRY5 has been developed for monitoring
the heavy metals mercury, silver, copper and chromium in contaminated waters in the Juru
Industrial Estate. The crude enzyme extract transformed soluble molybdenum
(phosphomolybdate) into a deep blue solution, which is inhibited by heavy metals such as
mercury, silver, copper and chromium. The IC50 and Limits of Detection (LOD) values for
mercury, copper, silver and cadmium were 0.245, 0.298, 0.367, 0.326, and 0.124, 0.086, 0.088
and 0.094 mg L-1, respectively. The assay is rapid, and can be carried out in less than 10 minutes.
In addition, the assay can be carried out at ambient temperature. The IC50 values for these heavy
metals are more sensitive than several established assays. Water samples from various locations
in the month of November from the Juru Industrial Estate (Penang) were tested for the presence
of heavy metals using the developed assay. Enzyme activity was nearly inhibited for water
samples from several locations. The presence of heavy metals was confirmed instrumentally
using Atomic Emission Spectrometry and a Flow Injection Mercury System. The assay is rapid
and simple and can be used as a first screening method for large scale monitoring of heavy
The pollution of heavy metals and toxic xenobiotics has become a central issue worldwide.
Bioremediation of these toxicants are being constantly carried out using novel microbes.
Molybdenum reduction to molybdenum blue is a detoxification process and mathematical
modelling of the reduction process can reveal important parameters such as specific reduction
rate, theoretical maximum reduction and whether reduction at high molybdenum concentration
affected the lag period of reduction. The used of linearization method through the use of natural
logarithm transformation, although popular, is inaccurate and can only give an approximate
value for the sole parameter measured; the specific growth rate. In this work, a variety of
models for such as logistic, Gompertz, Richards, Schnute, Baranyi-Roberts, Von Bertalanffy,
Buchanan three-phase and more recently Huang were utilized for the first time to obtain values
for the above parameters or constants. The modified Gompertz model was the best model in
modelling the Mo-blue production curve from Serratia marcescens strain DR.Y10 based on
statistical tests such as root-mean-square error (RMSE), adjusted coefficient of determination
(R2), bias factor (BF), accuracy factor (AF) and corrected AICc (Akaike Information Criterion).
Parameters obtained from the fitting exercise were maximum Mo-blue production rate (μm), lag
time (l) and maximal Mo-blue production (Ymax) of X (h-1), Y (h) and Z (nmole Mo-blue),
respectively. The application of primary population growth models in modelling the Moblue
production rate from this bacterium has become a successful undertaking. The model
may also be used in other heavy metals detoxification processes. The parameters
constants extracted from this work will be a substantial help for the future development
of further secondary models.
Water contamination by herbicides and chelating agents is increasing mainly due to the
increasing agricultural activities. Water contamination by these compounds has become a
concern due to their adverse effects to the environment and humans. Seven sampling sites of
water sources in Selangor and Johor were chosen for the study. Contamination level of
Mecoprop (MCCP), Nitrilotriacetic acid (NTA) and Ethylenediaminetetraacetic acid (EDTA) in
these water body areas was determined by using Gas Chromatography-Electron Capture
Detector (GC-ECD). Our results indicated that water samples of Sungai Melot in Selangor
showed the highest presence of EDTA. MCCP was detected at a high level at Sungai Sarang
Buaya, Johor while NTA showed similar level of concentration at three different sites, Ladang
10, Ladang Sayur and Mardi, Selangor.
The trend of global under-five child mortality rate showed a steady decrease at -3.14% per year
approaching the United Nations millennium development goals target (-4.0% reduction per year
from 1990-2015). This rate is usually inversely proportional to the nations GDP. However, the
progress in the recent years (2006-2012) in Malaysia has raised a disturbing concern with an
annual average increment of +0.81% per year. Thus, there is an urgent need to identify the
reasons of such risky ecosystem. By analyzing recorded data on river pollution from 2007-
2012, we found that river pollution has high correlation with the gross domestic products, not at
the same year, but for two years prior that indicates a lag time. We also found that under-five
child mortality has strong correlation with the river pollutions. The development-pollutionhealth
triangular cycle needs to be put in a balanced to ensure the nation prosperity and
sustainability of the nation.
Quinolines compounds are toxic pollutants. Their biodegradation by microbes represents a tool
for bioremediation. The growth of Klebsiella penumoniae on 2-methylquinoline shows typical
sigmoidal bacterial growth curves. Since there exists a variety of models for describing the
growth profile of microorganism such as logistic, Gompertz, Richards, Schnute, Baranyi-
Roberts, Von Bertalanffy, Buchanan three-phase and more recently Huang models, the growth
curves exhibit under such conditions would be an excellent study for finding the best model.
The Huang model was chosen as the best model based on statistical tests such as root-meansquare
error (RMSE), adjusted coefficient of determination (R2), bias factor (BF), accuracy
factor (AF) and corrected AICc (Akaike Information Criterion). Novel constants obtained from
the modelling exercise would be used for further secondary modelling.
Protein function depends greatly on its structure. Based on this principle, it is vital to study the
protein structure in order to understand its function. This study attempts to build the predicted
model of lipase gene in Rhodococcus sp. NAM81 using homology modelling method. The
predicted structure was then used to investigate the function of protein through several
bioinformatic tools. The DNA sequence of lipase gene was obtained from the Rhodococcus sp.
NAM81 genome scaffold. Blastx analysis showed 100% identity to the target enzyme andthe
appropriate template for homology modelling was determined using Blastp analysis. The 3D
protein structure was built using two homology modelling software, EsyPred3D and Swiss
Model Server. Both structures built obtained LGScore of greater than 4, which means they are
extremely good models according to ProQ validation criteria. Both structures also satisfied the
Ramachandran plot structure validation analysis. The predicted structures were 100% matched
with each other when superimposed with DaliLite pairwise. This shows that both structure
validation servers agreed on the same model. Structure analysis using ProFunc had found seven
motifs and active sites that indicate similar function of this protein with other known proteins.
Thus, this study has successfully produced a good 3D protein structure for the target enzyme.