Displaying publications 41 - 60 of 768 in total

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  1. Mining resettlement and rural development in Malaysia
    Khalid HN
    Asia Pac J Rural Dev, 1992 Jul;2(1):75-93.
    PMID: 12344616
    Matched MeSH terms: Metals*
  2. Fulltext Seasonal variation of heavy metals and metallothionein contents in Asian swamp eels, Monopterus albus (Zuiew, 1793) from Tumpat, Kelantan, Malaysia
    Sow AY, Ismail A, Zulkifli SZ, Amal MN, Hambali K
    BMC Pharmacol Toxicol, 2019 Jan 29;20(1):8.
    PMID: 30696486 DOI: 10.1186/s40360-019-0286-x
    BACKGROUND: Levels of toxic metal exposure in indigenous inhabitants are key bioindicators of the severity of environmental contamination. This study measured the seasonal variation of heavy metals and metallothionein (MT) contents in Asian swamp eels (Monopterus albus) from a paddy field situated in Tumpat, Kelantan, Malaysia, to identify prevalence, patterns and associations and togain insight on the suitability of MT as a biomarker for metal exposure.

    METHODS: Gill, muscle and liver tissues of M. albus (n = 50) sampled during the ploughing, seedling, growing and harvesting phases of rice growing were collected. The concentrations of copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), and cadmium (Cd) in these tissues were determined by flame atomic absorption spectrometry. MT from each sample was isolated and purified, and subsequently quantitated using UV spectrophotometry. Associations between metal and MT concentrations, season and tissue type were evaluated using Pearson correlation and ANOVA with post-hoc Tukey HSD analysis.

    RESULTS: Zn was present in higher quantities in gill and liver tissues, while Cu levels were elevated solely in liver. Patterns of non-essential metal accumulation were varied: Cd was detected in low concentrations in all tissues, while Pb and Ni were abundant in gill tissues across all seasons. MT concentration in liver tissue was consistently higher than that found in muscle or gill tissue, except during the growing phase. Moreover, significant correlations (P 

    Matched MeSH terms: Metals, Heavy/analysis*
  3. Fulltext Heavy Metal Adsorption onto Kappaphycus sp. from Aqueous Solutions: The Use of Error Functions for Validation of Isotherm and Kinetics Models
    Rahman MS, Sathasivam KV
    Biomed Res Int, 2015;2015:126298.
    PMID: 26295032 DOI: 10.1155/2015/126298
    Biosorption process is a promising technology for the removal of heavy metals from industrial wastes and effluents using low-cost and effective biosorbents. In the present study, adsorption of Pb(2+), Cu(2+), Fe(2+), and Zn(2+) onto dried biomass of red seaweed Kappaphycus sp. was investigated as a function of pH, contact time, initial metal ion concentration, and temperature. The experimental data were evaluated by four isotherm models (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich) and four kinetic models (pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models). The adsorption process was feasible, spontaneous, and endothermic in nature. Functional groups in the biomass involved in metal adsorption process were revealed as carboxylic and sulfonic acids and sulfonate by Fourier transform infrared analysis. A total of nine error functions were applied to validate the models. We strongly suggest the analysis of error functions for validating adsorption isotherm and kinetic models using linear methods. The present work shows that the red seaweed Kappaphycus sp. can be used as a potentially low-cost biosorbent for the removal of heavy metal ions from aqueous solutions. Further study is warranted to evaluate its feasibility for the removal of heavy metals from the real environment.
    Matched MeSH terms: Metals, Heavy/toxicity; Metals, Heavy/chemistry*
  4. Fulltext Health Risk Assessment of Heavy Metals from Smoked Corbicula fluminea Collected on Roadside Vendors at Kelantan, Malaysia
    Dee KH, Abdullah F, Md Nasir SNA, Appalasamy S, Mohd Ghazi R, Eh Rak A
    Biomed Res Int, 2019;2019:9596810.
    PMID: 31663001 DOI: 10.1155/2019/9596810
    Corbicula fluminea serves as traditional food to the local people in Kelantan, Malaysia. Concerns regarding river contamination, smoking method, and associated adverse effects on public health had been increasing. Hence, this study aims to measure the level of heavy metals (Cd, Cu, Mn, Pb, and Zn) and assess human health risk in C. fluminea consumption at Kelantan. Heavy-metal analysis was done using flame atomic absorption spectrophotometry, while human health risk was assessed using provisional tolerable weekly intake (PTWI), target hazard quotient (THQ), and hazard index (HI). The estimated weekly intake (EWI) for all metals was found within PTWI, while THQ for Cd, Cu, Mn, Pb, and Zn was 0.12, 0.06, 0.04, 0.41, and 0.03, respectively. The HI was calculated at 0.61 which is less than 1, considered as the safe consumption level. Therefore, C. fluminea consumption in this study was found safe from the health risk of noncarcinogenic effect over a lifetime.
    Matched MeSH terms: Metals, Heavy/chemistry*
  5. Comparison between procaine and isocarboxazid metabolism in vitro by a liver microsomal amidase-esterase
    Moroi K, Sato T
    Biochem Pharmacol, 1975 Aug 15;24(16):1517-21.
    PMID: 8
    Matched MeSH terms: Metals/pharmacology
  6. Properties of a cyclic 3'5'-nucleotide phosphodiesterase from Vigna mungo
    Lee CH, Abidin UZ
    Biochem. Int., 1989 Oct;19(4):745-53.
    PMID: 2559728
    Cyclic AMP phosphodiesterase (PDE) partially purified from roots of Vigna mungo exhibited optimum activity at pH 5.5 to 6.0 and maximum enzyme activity at 50 degrees C. Levels of PDE activity in roots remained relatively constant from the first to the eleventh day after germination; on the twelfth day there was a 400% increase in PDE activity. The enzyme was stable for at least 48 hours at 28 degrees C, retaining 92% of its original activity. Plant growth hormones including gibberellic acid, indoleacetic acid and kinetin at 1.0 and 10.0 microM concentrations did not have any significant effect on enzyme activity. Nucleotides tested including cyclic 2'3' AMP, cyclic 2'3' GMP completely abolished enzyme activity at 1.0mM while cyclic 3'5' GMP, cyclic 3'5' GMP, 2'deoxy 5' ATP, 2'deoxy 5'GTP and 5'ADP were also inhibitory to the enzyme. The enzyme was stimulated by Mg2+, Fe2+ and NH4+ while Cu2+ and Fe3+ were inhibitory. Theophylline, caffeine, phosphate, pyrophosphate and EDTA were inhibitory to the enzyme.
    Matched MeSH terms: Metals/pharmacology
  7. Phytotreatment of soil contaminated with used lubricating oil using Hibiscus cannabinus
    Abioye OP, Agamuthu P, Abdul Aziz AR
    Biodegradation, 2012 Apr;23(2):277-86.
    PMID: 21870160 DOI: 10.1007/s10532-011-9506-9
    Soil contamination by hydrocarbons, especially by used lubricating oil, is a growing problem in developing countries, which poses a serious threat to the environment. Phytoremediation of these contaminated soils offers environmental friendly and a cost effective method for their remediation. Hibiscus cannabinus was studied for the remediation of soil contaminated with 2.5 and 1% used lubricating oil and treated with organic wastes [banana skin (BS), brewery spent grain (BSG) and spent mushroom compost (SMC)] for a period of 90 days under natural conditions. Loss of 86.4 and 91.8% used lubricating oil was recorded in soil contaminated with 2.5 and 1% oil and treated with organic wastes respectively at the end of 90 days. However, 52.5 and 58.9% oil loss was recorded in unamended soil contaminated with 2.5 and 1% oil, respectively. The plant did not accumulate hydrocarbon from the soil but shows appreciable accumulation of Fe and Zn in the root and stem of H. cannabinus at the end of the experiment. The first order kinetic rate of uptake of Fe and Zn in H. cannabinus was higher in organic wastes amendment treatments compared to the unamended treatments, which are extremely low. The results of this study suggest that H. cannabinus has a high potential for remediation of hydrocarbon and heavy metal contaminated soil.
    Matched MeSH terms: Metals, Heavy/analysis
  8. The cadmium tolerance and bioaccumulation mechanism of Tetratostichococcus sp. P1: insight from transcriptomics analysis
    Sahabudin E, Kubo S, Yuzir MAM, Othman N, Nadia Md Akhir F, Suzuki K, et al.
    Bioengineered, 2024 Dec;15(1):2314888.
    PMID: 38375815 DOI: 10.1080/21655979.2024.2314888
    Cadmium (Cd) has become a severe issue in relatively low concentration and attracts expert attention due to its toxicity, accumulation, and biomagnification in living organisms. Cd does not have a biological role and causes serious health issues. Therefore, Cd pollutants should be reduced and removed from the environment. Microalgae have great potential for Cd absorption for waste treatment since they are more environmentally friendly than existing treatment methods and have strong metal sorption selectivity. This study evaluated the tolerance and ability of the microalga Tetratostichococcus sp. P1 to remove Cd ions under acidic conditions and reveal mechanisms based on transcriptomics analysis. The results showed that Tetratostichococcus sp. P1 had a high Cd tolerance that survived under the presence of Cd up to 100 µM, and IC50, the half-maximal inhibitory concentration value, was 57.0 μM, calculated from the change in growth rate based on the chlorophyll content. Long-term Cd exposure affected the algal morphology and photosynthetic pigments of the alga. Tetratostichococcus sp. P1 removed Cd with a maximum uptake of 1.55 mg g-1 dry weight. Transcriptomic analysis revealed the upregulation of the expression of genes related to metal binding, such as metallothionein. Group A, Group B transporters and glutathione, were also found upregulated. While the downregulation of the genes were related to photosynthesis, mitochondria electron transport, ABC-2 transporter, polysaccharide metabolic process, and cell division. This research is the first study on heavy metal bioremediation using Tetratostichococcus sp. P1 and provides a new potential microalga strain for heavy metal removal in wastewater.[Figure: see text]Abbreviations:BP: Biological process; bZIP: Basic Leucine Zipper; CC: Cellular component; ccc1: Ca (II)-sensitive cross complementary 1; Cd: Cadmium; CDF: Cation diffusion facilitator; Chl: Chlorophyll; CTR: Cu TRansporter families; DAGs: Directed acyclic graphs; DEGs: Differentially expressed genes; DVR: Divinyl chlorophyllide, an 8-vinyl-reductase; FPN: FerroportinN; FTIR: Fourier transform infrared; FTR: Fe TRansporter; GO: Gene Ontology; IC50: Growth half maximal inhibitory concentration; ICP: Inductively coupled plasma; MF: molecular function; NRAMPs: Natural resistance-associated aacrophage proteins; OD: Optical density; RPKM: Reads Per Kilobase of Exon Per Million Reads Mapped; VIT1: Vacuolar iron transporter 1 families; ZIPs: Zrt-, Irt-like proteins.
    Matched MeSH terms: Metals, Heavy*
  9. Fulltext Treatment of river water of Sg. Pusu by using magnesium oxide (MGO) coated with chitosan
    Nik Nur Syafika Pahri, Nur Huda Syazwani Jafri, Husna Ahmad Tajuddin, Yusilawati Ahmad Nor
    Biological and Natural Resources Engineering Journal, 2019;2(1):10-25.
    MyJurnal
    Effective treatment of wastewater is crucial in order to achieve a sustainable development. For instance, highly efficient treatment processes with low capital requirements are the major prerequisite for implementation of the advanced wastewater treatment operations. Among various available treatment methods, the application of coagulation-flocculation process by using natural coagulant; chitosan has vast advantages such as low operating cost, environmental friendly and highly effective in the wastewater treatment operations. The application of nanotechnology in numerous treatment techniques are considered as the most significant advances in water and wastewater treatment practices. The utilization of magnesium oxide (MgO) as nano-adsorbent has recently gained attention as a potential treatment method in water remediation particularly for treating effluents with high amount of organic dyes and heavy metals due to its high treatment efficiency, low cost, versatility and environment compatibility. The purpose of this study was to determine the effectiveness of coagulation-flocculation process when using novel coagulant in which MgO coated with chitosan by investigating the percentage removal of several significant parameters which were turbidity, chemical oxygen demand (COD) and suspended solid. The removal efficiencies were determined throughout a series of experiments carried out using a standard jar test procedure in which three different coagulants; chitosan, MgO coated with chitosan and MgO were tested on water samples taken from Sg. Pusu. In addition, a set of experiments was designed using response surface methodology (RSM) in order to optimize adsorption of chitosan into MgO. The experiments were conducted at various concentrations of chitosan (10-30 mg/ml) and selected MgO dosage ranges (10-30 mg). From the obtained results, it was found that chitosan-MgO coagulant has good removal efficiencies of turbidity, chemical oxygen demand (COD) and suspended solids at 92%, 91%, and 98% respectively from the optimization of adsorption of chitosan-MgO. The MgO coated with chitosan is the best coagulant in this study compared to chitosan and MgO alone because of the ability of treating the river water with up to 90 % removal for all the main parameters. The results showed that coagulation-flocculation is effective as a treatment for treating river water.
    Matched MeSH terms: Metals, Heavy
  10. Levels of metallic elements and their potential relationships to cognitive function among elderly from Federal Land Development Authority (FELDA) settlement in Selangor Malaysia
    Ghazali AR, Kamarulzaman F, Normah CD, Ahmad M, Ghazali SE, Ibrahim N, et al.
    Biol Trace Elem Res, 2013 Jun;153(1-3):16-21.
    PMID: 23475372 DOI: 10.1007/s12011-013-9642-7
    Exposure to toxic metals and excessive amount of trace elements is a risk factor of cognitive decline. Continuous monitoring of these elements by the use of metabolically inactive tissues such as fingernails may help in taking preventive measures to delay the cognitive decline process. In this study, the cognitive function of 54 elderlies (60-72 years old) from FELDA Sungai Tengi, Selangor, was evaluated using the Malay version of Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA). The levels of arsenic (As), cadmium (Cd), copper (Cu), manganese (Mn), lead (Pb), and zinc (Zn) in fingernail were detected using Inductively Coupled Plasma-Mass Spectrometry. Results showed that (92.6 %) our population was cognitively impaired based on the MoCA with mean score of 18.07 ± 5.11. The mean level of elements in fingernails for As, Cd, Cu, Mn, Pb, and Zn were 16.68 ± 3.52, 4.26 ± 0.91, 4.81 ± 1.16, 1.00 ± 0.23, 1.83 ± 0.47, and 40.86 ± 10.81 μg/g, respectively. Significant inverse correlations were observed between MoCA with age (r = -0.543, p 
    Matched MeSH terms: Metals/analysis; Metals/toxicity*
  11. Fulltext Hummingbird-Leaves-Reared Black Soldier Fly Prepupae: Assessment of Nutritional and Heavy Metal Compositions
    Kuppusamy G, Kong CK, Segaran GC, Tarmalingam E, Herriman M, Ismail MF, et al.
    Biology (Basel), 2020 Sep 05;9(9).
    PMID: 32899563 DOI: 10.3390/biology9090274
    Black soldier fly (BSF) larva is an attractive animal feed replacer due to its noticeable nutritional content. However, the conventional rearing method often resulted in BSF with undesirably high heavy metal residues that are harmful to animals. In this work, putrefied Sesbania grandiflora (S. Grandiflora) leaves were employed as feed to rear BSF larvae. The resultant BSF prepupae were found to contain 43.5% protein and 16.7% fat, reflecting a comparable protein content and a 2-fold reduction in crude fat than those reared using conventional kitchen waste. Moreover, high quantities of arginine (25.4 g/kg dry matter basis (DM)), carnitine (32.9 g/kg DM), and short-chain fatty acids, including lauric (40.00%), palmitic (19.20%), and oleic (12.10%) acids, have also been noticed in the BSF prepupae. Furthermore, the BSF larvae have been recorded with 0.185 mg/kg chromium, 0.380 mg/kg selenium, and mercury below the detection limit, which is far lower than those reared using conventional kitchen and agricultural wastes (≈1.7 mg/kg chromium, 1.2 mg/kg selenium, and 0.2 mg/kg mercury). Overall, the study shows that the nutritional quality of BSF prepupae is extensively improved when using S. Grandiflora as their feed. The resultant BSF prepupae may serve as an alternative feed for animal rearing.
    Matched MeSH terms: Metals, Heavy
  12. Synthesis and evaluation of antibacterial activity of transition metal-oleoyl amide complexes
    Farhan N, Al-Maleki AR, Sarih NM, Yahya R
    Bioorg Chem, 2023 Nov;140:106786.
    PMID: 37586131 DOI: 10.1016/j.bioorg.2023.106786
    Recent studies show that some metal ions, injure microbial cells in various ways due to membrane breakdown, protein malfunction, and oxidative stress. Metal complexes are suited for creating novel antibacterial medications due to their distinct mechanisms of action and the variety of three-dimensional geometries they can acquire. In this Perspective, the present study focused on new antibacterial strategies based on metal oleoyl amide complexes. Thus, oleoyl amides ligand (fatty hydroxamic acid and fatty hydrazide hydrate) with the transition metal ions named Ag (I), Co (II), Cu (II), Ni (II) and Sn (II) complexes were successfully synthesized in this study. The metals- oleoyl amide were characterized using elemental analysis, and fourier transforms infrared (FTIR) spectroscopy. The antibacterial effect of metals- oleoyl amide complexes was investigated for Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) by analysing minimum inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and scanning electron microscopy (SEM). The results showed that metal-oleoyl amide complexes have high antibacterial activity at low concentrations. This study inferred that metal oleoyl amide complexes could be utilised as a promising therapeutic antibacterial agent.
    Matched MeSH terms: Metals
  13. Acidophilic microorganisms in remediation of contaminants present in extremely acidic conditions
    Razia S, Hadibarata T, Lau SY
    Bioprocess Biosyst Eng, 2023 Mar;46(3):341-358.
    PMID: 36602611 DOI: 10.1007/s00449-022-02844-3
    Acidophiles are a group of microorganisms that thrive in acidic environments where pH level is far below the neutral value 7.0. They belong to a larger family called extremophiles, which is a group that thrives in various extreme environmental conditions which are normally inhospitable to other organisms. Several human activities such as mining, construction and other industrial processes release highly acidic effluents and wastes into the environment. Those acidic wastes and wastewaters contain different types of pollutants such as heavy metals, radioactive, and organic, whose have adverse effects on human being as well as on other living organisms. To protect the whole ecosystem, those pollutants containing effluents or wastes must be clean properly before releasing into environment. Physicochemical cleanup processes under extremely acidic conditions are not always successful due to high cost and release of toxic byproducts. While in case of biological methods, except acidophiles, no other microorganisms cannot survive in highly acidic conditions. Therefore, acidophiles can be a good choice for remediation of different types of contaminants present in acidic conditions. In this review article, various roles of acidophilic microorganisms responsible for removing heavy metals and radioactive pollutants from acidic environments were discussed. Bioremediation of various acidic organic pollutants by using acidophiles was also studied. Overall, this review could be helpful to extend our knowledge as well as to do further relevant novel studies in the field of acidic pollutants remediation by applying acidophilic microorganisms.
    Matched MeSH terms: Metals, Heavy*
  14. Fulltext A rapid inhibitive enzyme assay for monitoring heavy metals pollution in the Juru Industrial Estate
    Halmi, M.I.E., Baskaran Gunasekaran, Othman, A.R., Shukor, M.Y., Kamaruddin, K., Dahalan, F.A., et al.
    Bioremediation Science and Technology Research, 2015;3(2):7-12.
    MyJurnal
    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
    metals.
    Matched MeSH terms: Metals, Heavy
  15. Fulltext Near real-time biomonitoring of copper from an industrial complex effluent discharge site using a plant protease inhibitive assay
    Halmi, M.I.E., Khayat, M.E., Rahman, M.F.A., Gunasekaran, B., Masdor, N.A.
    Bioremediation Science and Technology Research, 2016;4(1):10-13.
    MyJurnal
    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 largescale
    biomonitoring works for the heavy metal copper from this area.
    Matched MeSH terms: Metals, Heavy
  16. Fulltext Partial purification of the molybdenum-reducing enzyme from Bacillus pumilus strain Lbna
    Abo-Shakeer, L.K.A., Yakasai, M.H., Rahman, M.F., Syed, M.A., Bakar, N.A., Othman, A.R.
    Bioremediation Science and Technology Research, 2016;4(1):14-17.
    MyJurnal
    Molybdenum is an emerging pollutant. Bioremediation of this heavy metal is possible by the
    mediation of Mo-reducing bacteria. These bacteria contain the Mo-reducing enzymes that can
    conver toxic soluble molybdenum into molybdenum blue; a less soluble and less toxic form of the
    metal. To date only the enzyme has been purified from only one bacterium. The aim of this study is
    to purify the Mo-reducing enzyme from a previously isolated Mo-reducing bacterium Bacillus
    pumilus strain Lbna using ammonium sulphate fractionation followed by ion exchange and then
    gel filtration. Two clear bands were obtained after the gel filtration step with molecular weights
    of 70 and 100 kDa. This indicates that further additional purification methods need to be used
    to get a purified fraction. Hence, additional steps of chromatography such as hydroxyapatite or
    chromatofocusing techniques can be applied in the future.
    Matched MeSH terms: Metals, Heavy
  17. Fulltext Assay for heavy metals using an inhibitive assay based on the acetylcholinesterase from Channa striatus
    Zulkifli, A.F., Tham, L.G., Perumal, N., Azzeme, A., Shukor, M.Y., Shaharuddin, N.A., et al.
    Bioremediation Science and Technology Research, 2017;5(1):7-11.
    MyJurnal
    Acetylcholinesterase (AChE) is usually used as an inhibitive assay for insecticides. A lesser
    known property of AChE is its inhibition by heavy metals. In this work we evaluate an AChE
    from brains of striped snakehead (Channa striatus) wastes from aquaculture industry as an
    inhibitive assay for heavy metals. We discovered that the AChE was inhibited almost completely
    by Hg2+, Ag2+ and Cu2+ during an initial screening. When tested at various concentrations, the
    heavy metals exhibited exponential decay type inhibition curves. The calculated IC50 for the
    heavy metals Hg2+, Ag2+, Pb2+, Cu2+ and Cr6+ were 0.08432, 0.1008, 0.1255, 0.0871, and 0.1771,
    respectively. The IC50 for these heavy metals are comparable and some are lower than the IC50
    values from the cholinesterases from previously studied fish. The assay can be carried out in less
    than 30 minutes at ambient temperature.
    Matched MeSH terms: Metals, Heavy
  18. Fulltext Kinetic studies of the partially purified molybdenum-reducing enzyme from Bacillus pumilus strain Lbna
    Abo-Shakeer, L.K.A., Rahman, M.F.A., Yakasai, H., Syed, M.A., Shukor M.Y., Bakar, N.A., et al.
    Bioremediation Science and Technology Research, 2017;5(1):18-23.
    MyJurnal
    Bacterial based remediation of environmental toxicants is a promising innovative technology
    for molybdenum pollution. To date, the enzyme responsible for molybdate reduction to Moblue
    from bacteria show that the Michaelis-Menten constants varies by one order of magnitude.
    It is important that the constants from newer enzyme sources be characterized so that a
    comparison can be made. The aim of this study is to characterize kinetically the enzyme from a
    previously isolated Mo-reducing bacterium; Bacillus pumilus strain Lbna. The maximum
    activity of this enzyme occurred at pH 5.5 and in between 25 and 35 oC. The Km and Vmax of
    NADH were 6.646 mM and 0.057 unit/mg enzyme, while the Km and Vmax of LPPM were 3.399
    mM and 0.106 unit/mg enzyme. The results showed that the enzyme activity for Bacillus
    pumilus strain Lbna were inhibited by all heavy metals used. Zinc, copper, silver, chromium,
    cadmium and mercury all caused more than 50% inhibition to the Mo-reducing enzyme activity
    with copper being the most potent with an almost complete inhibition of enzyme activity
    observed.
    Matched MeSH terms: Metals, Heavy
  19. Fulltext Phenol removal via cellular immobilization: a review
    Aisami Abubakar, Mohd Yunus Shukor
    Bioremediation Science and Technology Research, 2017;5(2):1-7.
    MyJurnal
    Environmental pollution is one of the major concerns in the 21st century; where billions of tonnes
    of harmful chemicals are produced by industries such as petroleum, paints, food, rubber, and
    plastic. Phenol and its derivatives infiltrate the ecosystems and have become one of the top major
    pollutants worldwide. This review covers the major aspects of immobilization of phenoldegrading
    bacteria as a method to improve phenol bioremediation. The use of various forms of
    immobilization matrices is discussed along with the advantages and disadvantages of each of the
    immobilization matrices especially when environmental usage is warranted. To be used as a
    bioremediation tool, the immobilized system must not only be effective, but the matrices must be
    non-toxic, non-polluting and if possible non-biodegradable. The mechanical, biological and
    chemical stability of the system is paramount for long-term activity as well as price is an
    important factor when the very large scale is a concern. The system must also be able to tolerate
    high concentration of other toxicants especially heavy metals that form as co-contaminants, and
    most immobilized systems are geared towards this last aspect as immobilization provides
    protection from other contaminants.
    Matched MeSH terms: Metals, Heavy
  20. Fulltext Assay for heavy metals using an inhibitive assay based on the acetylcholinesterase from Clarias batrachus
    Abubakar M. Umar, Tham, Lik Gin, Natarajan Perumal, Nur Adeela Yasid, Hassan Mohd Daud, Mohd Yunus Shukor
    Bioremediation Science and Technology Research, 2016;4(2):6-10.
    MyJurnal
    Acetylcholinesterase (AChE) is usually used as an inhibitive assay for insecticides. A lesserknown
    property of AChE is its inhibition by heavy metals. In this work, we evaluate an AChE
    from brains of Clarias batrachus (catfish) exposed to wastes from aquaculture industry as an
    inhibitive assay for heavy metals. We discovered that the AChE was inhibited completely by
    Hg2+, Ag2+, Pb2+, Cu2+, Cd2+, Cr6+ and Zn2+ during initial screening. When tested at various
    concentrations, the heavy metals exhibited exponential decay type inhibition curves. The
    calculated IC50 (mg/L) for the heavy metals Ag2+, Cu2+, Hg2+, Cr6+ and Cd2+ were 0.088, 0.078,
    0.071, 0.87 and 0.913, respectively. The IC50 for these heavy metals are comparable, and some
    are lower than the IC50 values from the cholinesterases from previously studied fish. The assay
    can be carried out in less than 30 minutes at ambient temperature.
    Matched MeSH terms: Metals, Heavy
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