Publications by authors named "Wai-Hung Lo"

With our recent success in developing a recombinant human arginase drug against broad-spectrum cancer cell lines, we have explored the potential of a recombinant arginase mutant (BCA-M) for human cervical cancer treatment. Our studies demonstrated that BCA-M significantly inhibited the growth of human cervical cancer cells in vitro regardless of argininosuccinate synthetase (ASS) and argininosuccinate lyase (ASL) expression. Drug susceptibilities correlate well with the expressions of major urea cycle genes and completeness of L-arginine regeneration pathways.

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L-arginine (L-Arg) depletion induced by randomly PEGylated arginine deiminase (ADI-PEG20) can treat arginosuccinate synthase (ASS)-negative cancers, and ADI-PEG20 is undergoing phase III clinical trials. Unfortunately, ASS-positive cancers are resistant to ADI-PEG20. Moreover, the yield of ADI production is low because of the formation of inclusion bodies.

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L-Arginine (L-Arg) depletion has attracted great attention in cancer therapy. Although two types of arginine-depleting enzymes, arginine deiminase (ADI) and human arginase I, are undergoing clinical trials, random site of PEGylation, low efficacy of heavy metal as co-factor, and immunogenicity limit the performance of these drugs and cause difficulty in a homogeneous production. Here we screened ten catalytic metal ions and have successfully produced a site-specific mono-PEGylated human arginase I mutant by conjugating the Cys residue to PEG-maleimide to minimize the decrease in activity and produce a homogeneous product.

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In this work, we examined the performance of 2D titanate nanosheets for dye adsorption. Their adsorption capacity for methylene blue (MB) is up to 3937 mg g, which is more than 10 times higher than active carbon and occupies the highest place among all the reports.

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  • A new nanosensor has been created using hen lysozyme amyloid fibrils to detect chromium (Cr) effectively.
  • The sensor utilizes acidified diphenylcarbazide (DPC) as a colorimetric probe to indicate the presence of chromium.
  • It can identify Cr at very low concentrations (parts per billion) without needing complicated sample preparation or expensive equipment.
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  • Recombinant human arginase (rhArg) is being studied as a treatment for cancer by depriving cancer cells of arginine, particularly those lacking ornithine carbamoyl transferase (OCT) and argininosuccinate synthetase (ASS).
  • Quantitative PCR analysis revealed low OCT expression but high ASS expression in three human prostate cancer cell lines (LNCaP, PC-3, DU-145), all showing significant sensitivity to rhArg.
  • Exposure to rhArg led to cytotoxic effects without significant apoptosis, indicating potential involvement of autophagy in the cell death process, making rhArg a promising option for prostate cancer therapy.
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This article presents an overview with critical analysis of technical applicability of advanced oxidation process (AOP) in removing chelating agents from aqueous solution. Apart from the effect of metals for chelating agents as a major influencing factor, selected information such as pH, oxidant's dose, concentrations of pollutants and treatment performance is presented. The performance of individual AOP is compared.

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Melanoma has been shown to require arginine for growth, thus providing a potential Achilles' heel for therapeutic exploitation. Our investigations show that arginine depletion, using a recombinant form of human arginase I (rhArg), efficiently inhibits the growth of mammalian melanoma cell lines in vitro. These cell lines are consistently deficient in ornithine transcarbamylase (OTC) expression, correlating with their sensitivity to rhArg.

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  • The study evaluated how well H(2)O(2) oxidation and its combination with granular activated carbon (GAC) can treat leachate from a landfill with low biodegradability.
  • The integrated treatment with H(2)O(2) and GAC showed significantly better removal of contaminants (82% COD and 59% NH(3)-N) compared to using H(2)O(2) alone (33% COD and 4.9% NH(3)-N) or GAC alone (58% COD).
  • Even though the treated leachate did not meet local discharge limits for COD and NH(3)-N, the integrated approach improved the biodegradability ratio by 350%, allowing
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  • Hepatocellular carcinoma (HCC) often lacks the enzyme argininosuccinate synthetase (ASS), making it auxotrophic for arginine, and while arginine-depleting enzyme arginine deiminase (ADI) helps ASS-deficient tumors, many ASS-positive HCC cells remain resistant to it despite needing arginine for growth.
  • Direct evidence shows that recombinant human arginase (rhArg) effectively inhibits ASS-positive HCC cells, whereas ADI has little impact; the lack of ornithine transcarbamylase (OTC) in these cells correlates with their sensitivity to rhArg treatment.
  • Pretesting for ASS and OTC expression in tumors could predict responsiveness to arginine-depleting therapies
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Polyhydroxyalkanoates (PHAs) are polyesters of hydroxyalkanoates synthesized by numerous bacteria as intracellular carbon and energy storage compounds and accumulated as granules in the cytoplasm of cells. In this work, we constructed two recombinant plasmids, pBE2C1 and pBE2C1AB, containing one or two PHA synthse genes, respectively. The two plasmids were inserted into Bacillus subtilis DB104 to generate modified strains, B.

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Laboratory experiments were undertaken to investigate the treatment performances of ozonation alone and/or its combination with granular activated carbon (GAC) adsorption for raw leachate from the NENT landfill (in Hong Kong). To improve its removal of recalcitrant contaminants from the leachate, the surface of GAC was oxidized with ozone prior to treatment. With respect to ozone dose and pH, the removal of COD and/or NH(3)-N from ozonation alone and combined ozone-GAC adsorption were evaluated and compared to those of other physico-chemical treatments in some reported studies.

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  • The paper reviews various physico-chemical techniques for treating landfill leachate, focusing on methods like coagulation-flocculation, chemical precipitation, ammonium stripping, membrane filtration, and adsorption.
  • It evaluates the advantages and limitations of these techniques by comparing operating conditions, treatment efficiencies, and characteristics of the leachate, revealing that no single method is universally effective for removing persistent compounds.
  • Combined treatments, particularly using membrane filtration with biological methods, have shown high effectiveness in removing chemical oxygen demand (COD) and ammonium nitrogen (NH3-N), emphasizing the need to select methods based on leachate characteristics, technical feasibility, costs, and regulatory requirements.
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  • The article evaluates the effectiveness and cost of low-cost adsorbents made from agricultural waste and industrial by-products in removing heavy metals from contaminated water, comparing them to activated carbon.
  • The study reviews 102 published papers and reveals that many agricultural waste adsorbents outperform activated carbon in terms of adsorption capacity for specific heavy metals like chromium and nickel.
  • Overall, low-cost adsorbents emerge as promising alternatives for treating metal-contaminated wastewater, with factors like effectiveness, cost, and specific adsorbent properties influencing selection for practical applications.
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An air-stable catalyst system Ir-(P-Phos) catalyst was found to be highly effective in the asymmetric hydrogenation of quinoline derivatives. The catalyst immobilized in DMPEG was efficiently recovered and reused eight times, retaining reactivity and enantioselectivity.

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  • Plastic waste is a significant global environmental issue, driving increased interest in biodegradable plastics.
  • In this study, three Escherichia coli strains were transformed to produce polyhydroxyalkanoates (PHA), with E. coli HMS174 yielding the most P(HB-HV) at 10.27 g/L and 43% PHA content.
  • The research highlights the importance of selecting the right E. coli strain for effective PHA production, indicating potential industrial and medical applications for the resulting biopolymer.
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Sphaerotilus natans is a sheathed bacterium existing in the activated sludge of wastewater treatment plants. It is one of the filamentous bacteria causing the bulking and foaming difficulties of activated sludge. Isolating the strain and culturing it in an axenic environment could not only provide the metabolic knowledge of the strains that would be useful in the development of wastewater treatment methods, but also could enable us to gain an understanding of the mechanism by which poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (poly[3-HB-co-3-HV]) is produced by this strain.

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A series of N-protected peptide alcohols were synthesized using amino alcohols with unprotected hydroxy groups as amino components by the catalysis of subtilisin or alpha-chymotrypsin in organic solvents. N-protected aromatic amino acid esters were more suitable as acyl donors for subtilisin. The influences of different N-protecting groups, organic solvents, and content of water on synthesis of N-protected peptide alcohols were systematically studied.

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