Displaying publications 41 - 60 of 385 in total

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  1. Letchumanan D, Sok SPM, Ibrahim S, Nagoor NH, Arshad NM
    Biomolecules, 2021 04 12;11(4).
    PMID: 33921379 DOI: 10.3390/biom11040564
    Plants are rich in phytoconstituent biomolecules that served as a good source of medicine. More recently, they have been employed in synthesizing metal/metal oxide nanoparticles (NPs) due to their capping and reducing properties. This green synthesis approach is environmentally friendly and allows the production of the desired NPs in different sizes and shapes by manipulating parameters during the synthesis process. The most commonly used metals and oxides are gold (Au), silver (Ag), and copper (Cu). Among these, Cu is a relatively low-cost metal that is more cost-effective than Au and Ag. In this review, we present an overview and current update of plant-mediated Cu/copper oxide (CuO) NPs, including their synthesis, medicinal applications, and mechanisms. Furthermore, the toxic effects of these NPs and their efficacy compared to commercial NPs are reviewed. This review provides an insight into the potential of developing plant-based Cu/CuO NPs as a therapeutic agent for various diseases in the future.
    Matched MeSH terms: Copper/chemistry*
  2. Halmi, M.I.E., Baskaran Gunasekaran, Othman, A.R., Shukor, M.Y., Kamaruddin, K., Dahalan, F.A., et al.
    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: Copper
  3. Othman, A.R., Rahman, M.F., Shukor, M.Y., Abu Zeid, I.M., Ariffin, F.
    MyJurnal
    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.
    Matched MeSH terms: Copper
  4. Halmi, M.I.E., Khayat, M.E., Rahman, M.F.A., Gunasekaran, B., Masdor, N.A.
    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: Copper
  5. Mohd Khalizan Sabullah, Azlan Jualang Gansau, Mohd Rosni Sulaiman, Fisal Ahmad
    MyJurnal
    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.
    Matched MeSH terms: Copper; Copper Sulfate
  6. Mohd Khalizan Sabullah, Azlan Jualang Gansau, Mohd Yunus Shukor, Baskaran Gunasekaran, Nor Arifin Shamaan, Mohd Rosni Sulaiman
    MyJurnal
    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.
    Matched MeSH terms: Copper
  7. Abo-Shakeer, L.K.A., Rahman, M.F.A., Yakasai, H., Syed, M.A., Shukor M.Y., Bakar, N.A., et al.
    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: Copper
  8. Tan WS, Ting AS
    Bioresour Technol, 2014 May;160:115-8.
    PMID: 24405651 DOI: 10.1016/j.biortech.2013.12.056
    This study evaluated the use of alginate-immobilized bentonite to remove Cu(II) as an alternative to mitigate clogging problems. The adsorption efficacy (under the influence of time, pH and initial Cu(II) concentration) and reusability of immobilized-bentonite (1% w/v bentonite) was tested against plain alginate beads. Results revealed that immobilized bentonite demonstrated significantly higher sorption efficacy compared to plain alginate beads with 114.70 and 94.04 mg Cu(II) adsorbed g(-1) adsorbent, respectively. Both sorbents were comparable in other aspects where sorption equilibrium was achieved within 6 h, with optimum pH between pH 4 and 5 for adsorption, displayed maximum adsorption capacity at initial Cu(II) concentrations of 400 mg l(-1), and demonstrated excellent reusability potential with desorption greater than 90% throughout three consecutive adsorption-desorption cycles. Both sorbents also conformed to Langmuir isotherm and pseudo-second order kinetic model. Immobilized bentonite is therefore recommended for use in water treatments to remove Cu(II) without clogging the system.
    Matched MeSH terms: Copper/isolation & purification*
  9. Tan WS, Ting AS
    Bioresour Technol, 2012 Nov;123:290-5.
    PMID: 22940332 DOI: 10.1016/j.biortech.2012.07.082
    Cu(II) removal efficacies of alginate-immobilized Trichoderma asperellum using viable and non-viable forms were investigated with respect to time, pH, and initial Cu(II) concentrations. The reusability potential of the biomass was determined based on sorption/desorption tests. Cu(II) biosorption by immobilized heat-inactivated T. asperellum cells was the most efficient, with 134.22mg Cu(II) removed g(-1) adsorbent, compared to immobilized viable cells and plain alginate beads (control) with 105.96 and 94.04mg Cu(II) adsorbed g(-1) adsorbent, respectively. Immobilized non-viable cells achieved equilibrium more rapidly within 4h. For all biosorbents, optimum pH for Cu(II) removal was between pH 4 and 5. Reusability of all biosorbents were similar, with more than 90% Cu(II) desorbed with HCl. These alginate-immobilized cells can be applied to reduce clogging and post-separation process incurred from use of suspended biomass.
    Matched MeSH terms: Copper/isolation & purification*; Copper/pharmacology
  10. Aziz HA, Adlan MN, Ariffin KS
    Bioresour Technol, 2008 Apr;99(6):1578-83.
    PMID: 17540556
    This paper presents the results of research on heavy metals removal from water by filtration using low cost coarse media which could be used as an alternative approach to remove heavy metals from water or selected wastewater. A series of batch studies were conducted using different particle media (particle size 2.36-4.75 mm) shaken with different heavy metal solutions at various pH values to see the removal behaviour for each metal. Each solution of cadmium (Cd), lead (Pb), zinc (Zn), nickel (Ni), copper (Cu) and chromium (Cr(III)) with a concentration of 2 mg/L was shaken with the media. At a final pH of 8.5, limestone has significantly removed more than 90% of most metals followed by 80% and 65% removals using crushed bricks and gravel, respectively. The removal by aeration and settlement methods without solid media was less than 30%. Results indicated that the removal of heavy metals was influenced by the media and not directly by the pH. Investigations on the removal behaviour of these metals indicated that rough solid media with the presence of carbonate were beneficial for the removal process. Adsorption and precipitation as metals oxide and probably as metals carbonate were among the two mechanisms that contributed to the removal of metals from solution.
    Matched MeSH terms: Copper/chemistry*
  11. Ho MC, Wu TY
    Bioresour Technol, 2020 Apr;301:122684.
    PMID: 31954964 DOI: 10.1016/j.biortech.2019.122684
    In this study, a novel Type II deep eutectic solvent (DES) namely, choline chloride:copper(II) chloride dihydrate (ChCl:CuCl2·2H2O) was used to pretreat oil palm fronds (OPFs). The sequential pretreatment with alkaline hydrogen peroxide (0.25 vol%, 90 min) at ambient conditions and a Type II DES (90 °C, 3 h) at a later stage resulted in a delignification of 55.14% with high xylan (80.79%) and arabinan (98.02%) removals. The characterizations of pretreated OPFs confirmed the excellent performance of DES in OPF fractionation. Thus, the application of a Type II DES at ambient pressure and relatively lower temperature was able to improve the lignin and hemicellulose removals from OPFs.
    Matched MeSH terms: Copper
  12. Stepien M, Hughes DJ, Hybsier S, Bamia C, Tjønneland A, Overvad K, et al.
    Br J Cancer, 2017 Feb 28;116(5):688-696.
    PMID: 28152549 DOI: 10.1038/bjc.2017.1
    BACKGROUND: Copper and zinc are essential micronutrients and cofactors of many enzymatic reactions that may be involved in liver-cancer development. We aimed to assess pre-diagnostic circulating levels of copper, zinc and their ratio (Cu/Zn) in relation to hepatocellular carcinoma (HCC), intrahepatic bile duct (IHBD) and gall bladder and biliary tract (GBTC) cancers.

    METHODS: A nested case-control study was conducted within the European Prospective Investigation into Cancer and Nutrition cohort. Serum zinc and copper levels were measured in baseline blood samples by total reflection X-ray fluorescence in cancer cases (HCC n=106, IHDB n=34, GBTC n=96) and their matched controls (1:1). The Cu/Zn ratio, an indicator of the balance between the micronutrients, was computed. Multivariable adjusted odds ratios and 95% confidence intervals (OR; 95% CI) were used to estimate cancer risk.

    RESULTS: For HCC, the highest vs lowest tertile showed a strong inverse association for zinc (OR=0.36; 95% CI: 0.13-0.98, Ptrend=0.0123), but no association for copper (OR=1.06; 95% CI: 0.45-2.46, Ptrend=0.8878) in multivariable models. The calculated Cu/Zn ratio showed a positive association for HCC (OR=4.63; 95% CI: 1.41-15.27, Ptrend=0.0135). For IHBC and GBTC, no significant associations were observed.

    CONCLUSIONS: Zinc may have a role in preventing liver-cancer development, but this finding requires further investigation in other settings.

    Matched MeSH terms: Copper/blood*
  13. Ali MF, Heng LY, Ratnam W, Nais J, Ripin R
    Bull Environ Contam Toxicol, 2004 Sep;73(3):535-42.
    PMID: 15386176
    Matched MeSH terms: Copper*
  14. Low KS, Lee CK, Lee TS
    Bull Environ Contam Toxicol, 1996 Mar;56(3):405-12.
    PMID: 8825962
    Matched MeSH terms: Copper/metabolism*
  15. Low KS, Lee CK, Ow-Wee ST
    Bull Environ Contam Toxicol, 1995 Aug;55(2):270-5.
    PMID: 7579934
    Matched MeSH terms: Copper/metabolism; Copper/chemistry
  16. Mokhtar MB, Awaluddin AB, Fong CW, Woojdy WM
    Bull Environ Contam Toxicol, 1994 Jan;52(1):149-54.
    PMID: 8130410
    Matched MeSH terms: Copper*
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