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1. Lignin oxidation by laccase isozymes from Trametes versicolor and role of the mediator 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) in kraft lignin depolymerization.

Author

Bourbonnais R, Paice MG, Reid ID, Lanthier P, and Yaguchi M

Subjects
Amino Acid Sequence, Benzothiazoles, Biopolymers metabolism, Fungal Proteins isolation & purification, Hot Temperature, Isoenzymes isolation & purification, Laccase, Molecular Sequence Data, Oxidation-Reduction, Oxidoreductases isolation & purification, Wood, Fungal Proteins metabolism, Isoenzymes metabolism, Lignin metabolism, Oxidoreductases metabolism, Polyporaceae enzymology, Sulfonic Acids pharmacology
Abstract

Two laccase isozymes (I and II) produced by the white-rot fungus Trametes versicolor were purified, and their reactivities towards various substrates and lignins were studied. The N-terminal amino acid sequences of these enzymes were determined and compared to other known laccase sequences. Laccase II showed a very high sequence similarity to a laccase which was previously reported to depolymerize lignin. The reactivities of the two isozymes on most of the substrates tested were similar, but there were some differences in the oxidation rate of polymeric substrates. We found that the two laccases produced similar qualitative effects on kraft lignin and residual lignin in kraft pulp, with no evidence of a marked preference for depolymerization by either enzyme. However, the presence of the mediator 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) prevented and reversed the polymerization of kraft lignin by either laccase. The delignification of hardwood and softwood kraft pulps with the two isozymes and the mediator was compared; either laccase was able to reduce the kappa number of pulp, but only in the presence of 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate).

Published
1995
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2. Cloning, sequence analysis, and expression of ligninolytic phenoloxidase genes of the white-rot basidiomycete Coriolus hirsutus.

Author

Kojima Y, Tsukuda Y, Kawai Y, Tsukamoto A, Sugiura J, Sakaino M, and Kita Y

Subjects
Alleles, Amino Acid Sequence, Base Sequence, Basidiomycota enzymology, Cloning, Molecular, Gene Expression, Laccase, Molecular Sequence Data, Oligonucleotide Probes, Restriction Mapping, Sequence Homology, Nucleic Acid, Basidiomycota genetics, Genes, Fungal, Isoenzymes genetics, Oxidoreductases genetics
Abstract

Two cDNAs and two genomic DNAs coding for the allelic forms of the ligninolytic phenoloxidase were isolated from the white-rot fungus Coriolus hirsutus. The cloned genes were identified in genetic libraries by hybridization screening using four deoxyoligonucleotide probes which corresponded to the partial amino acid sequence of the purified enzyme. Each cDNA encoded the full-length of the phenoloxidase, a protein consisting of 499 amino acid residues, and its putative signal peptide of 21 amino acid residues. The nucleotide sequences of the two alleles differed by 18 single base changes within the open reading frames resulting in one amino acid substitution. Ten small introns interrupted both genomic DNAs as indicated by direct comparison with the corresponding cDNAs. Putative eukaryotic regulatory sequences, "CAAT" and "TATA," were observed in the 5'-flanking region of both genomic DNAs. Each of the phenoloxidase cDNAs was successfully expressed in an active form in Saccharomyces cerevisiae using the useful yeast expression vector YEp51.

Published
1990

3. Plasmepsin II–III copy number accounts for bimodal piperaquine resistance among Cambodian Plasmodium falciparum

Author

Bopp, S, Magistrado, P, Wong, W, Schaffner, S, Mukherjee, A, Lim, P, Dhorda, M, Amaratunga, C, Woodrow, C, Ashley, E, White, N, Dondorp, A, Fairhurst, R, Ariey, F, Menard, D, Wirth, D, Volkman, S, Harvard T.H. Chan School of Public Health, Broad Institute of MIT and Harvard (BROAD INSTITUTE), Harvard Medical School [Boston] (HMS)-Massachusetts Institute of Technology (MIT)-Massachusetts General Hospital [Boston], National Institutes of Health [Bethesda] (NIH), WWARN Asia Regional Centre [Bangkok, Thailand], Mahidol University [Bangkok], Mahidol Oxford Tropical Medicine Research Unit, University of Oxford-Mahidol University [Bangkok], Myanmar Oxford Clinical Research Unit [Yangon, Myanmar], Centre for Tropical Medicine and Global Health [Oxford, UK], Nuffield Department of Medicine [Oxford, UK] (Big Data Institute), University of Oxford-University of Oxford, Mahidol Oxford Tropical Medicine Research Unit (MORU), University of Oxford-Mahidol University [Bangkok]-Wellcome Trust, Institut Cochin (IC UM3 (UMR 8104 / U1016)), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Biologie des Interactions Hôte-Parasite - Biology of Host-Parasite Interactions, Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Simmons college, This work was supported in part by the Intramural Research Program of the National Institute of Allergy and Infectious Diseases, National Institutes of Health., We thank Courtney Edison for slide reading and subcloning the KH001_053 isolate., The computations in this paper were run on the Odyssey cluster supported by the FAS Division of Science, Research Computing Group at Harvard University. N.J.W., C.J.W. were supported by Bill and Melinda Gates Foundation Global Health Grant Number OPP1040463, which also funded culture adaptation of the parasites described herein. Additional support was provided to DFW by the Bill and Melinda Gates Foundation Global Health Grant Number OPP1053604. This document is an output from a project of the Tracking Resistance to Artemisinin Collaboration funded by the UK Department for International Development (DFID) for the benefit of developing countries. However, the views expressed and information contained in it are not necessarily those of or endorsed by DFID, which can accept no responsibility for such views or for any reliance place on them., University of Oxford [Oxford]-Mahidol University [Bangkok], University of Oxford [Oxford]-University of Oxford [Oxford], Wellcome Trust-Mahidol University [Bangkok]-University of Oxford [Oxford], and Institut Pasteur [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Infectious-disease epidemiology, DNA Copy Number Variations, Whole Genome Sequencing, Cell Survival, Science, Plasmodium falciparum, Drug Resistance, Gene Dosage, Protozoan Proteins, Article, Malaria, Target validation, Isoenzymes, Antimalarials, parasitic diseases, Quinolines, Aspartic Acid Endopeptidases, Humans, lcsh:Q, [SDV.MP.PAR]Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, lcsh:Science, Cambodia, Antiparasitic agents
Abstract

Multidrug resistant Plasmodium falciparum in Southeast Asia endangers regional malaria elimination and threatens to spread to other malaria endemic areas. Understanding mechanisms of piperaquine (PPQ) resistance is crucial for tracking its emergence and spread, and to develop effective strategies for overcoming it. Here we analyze a mechanism of PPQ resistance in Cambodian parasites. Isolates exhibit a bimodal dose–response curve when exposed to PPQ, with the area under the curve quantifying their survival in vitro. Increased copy number for plasmepsin II and plasmepsin III appears to explain enhanced survival when exposed to PPQ in most, but not all cases. A panel of isogenic subclones reinforces the importance of plasmepsin II–III copy number to enhanced PPQ survival. We conjecture that factors producing increased parasite survival under PPQ exposure in vitro may drive clinical PPQ failures in the field., Piperaquine (PPQ) resistance of Plasmodium is an increasing problem. Here, Bopp et al. find a bimodal dose−response curve of Cambodian isolates exposed to PPQ, with the area under the curve correlating with in vitro PPQ resistance, and show the importance of Plasmepsin II–III copy number to PPQ resistance.

Published
2018