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Carrero JC, Curay-Herrera V, Chacón-Niño L, Krengel F, Guzmán-Gutiérrez SL, Silva-Miranda M, González-Ramírez LC, Bobes RJ, Espitia C, Reyes-Chilpa R, Laclette JP. Potent Anti-amoebic Effects of Ibogaine, Voacangine and the Root Bark Alkaloid Fraction of Tabernaemontana arborea. PLANTA MEDICA 2023; 89:148-157. [PMID: 35338475 DOI: 10.1055/a-1809-1157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Plants of Tabernaemontana species have several pharmacological activities including antimicrobial effects. Amoebiasis continues to be a public health problem, with increasing evidence of resistance to metronidazole. In this study, we assessed the effect of the alkaloid fraction of T. arborea root bark and the alkaloids ibogaine and voacangine on the viability and infectivity of Entamoeba histolytica trophozoites. Cultures were exposed to 0.1 - 10 µg/mL for 24, 48 and 72 h, and viability was then determined using a tetrazolium dye reduction assay and type of cellular death analyzed by flow cytometry. Results showed that the alkaloid fraction, but mainly ibogaine and voacangine alkaloids, exhibited potent dose-dependent anti-amoebic activity at 24 h post-exposure (IC50 4.5 and 8.1 µM, respectively), comparable to metronidazole (IC50 6.8 µM). However, the effect decreased after 48 and 72 h of exposure to concentrations below 10 µg/mL, suggesting that the alkaloids probably were catabolized to less active derivatives by the trophozoites. The treatment of trophozoites with the IC50 s for 24 h induced significant morphological changes in the trophozoites, slight increase in granularity, and death by apoptonecrosis. The capacity of T. arborea alkaloids to inhibit the development of amoebic liver abscesses in hamsters was evaluated. Results showed that even when the treatments reduced the number of amoebic trophozoites in tissue sections of livers, they were unable to limit the formation of abscesses, suggesting their rapid processing to inactive metabolites. This work leaves open the possibility of using Tabernaemontana alkaloids as a new alternative for amoebiasis control.
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Affiliation(s)
- Julio César Carrero
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Violeta Curay-Herrera
- Escuela Profesional de Ciencias Biológicas, Facultad de Ciencias, Universidad de Piura, Piura, Perú
| | - Lysette Chacón-Niño
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Felix Krengel
- Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad de México, México
| | | | - Mayra Silva-Miranda
- CONACyT-Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Luisa-Carolina González-Ramírez
- Grupo de Investigación "Análisis de Muestras Biológicas y Forenses", Carrera Laboratorio Clínico, Facultad de Ciencias de la Salud, Universidad Nacional de Chimborazo, Riobamba, Ecuador
| | - Raúl J Bobes
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Clara Espitia
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Ricardo Reyes-Chilpa
- Departamento de Productos Naturales, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Juan-Pedro Laclette
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
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Mechanistic basis for multidrug resistance and collateral drug sensitivity conferred to the malaria parasite by polymorphisms in PfMDR1 and PfCRT. PLoS Biol 2022; 20:e3001616. [PMID: 35507548 PMCID: PMC9067703 DOI: 10.1371/journal.pbio.3001616] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 03/31/2022] [Indexed: 01/16/2023] Open
Abstract
Polymorphisms in the Plasmodium falciparum multidrug resistance protein 1 (pfmdr1) gene and the Plasmodium falciparum chloroquine resistance transporter (pfcrt) gene alter the malaria parasite’s susceptibility to most of the current antimalarial drugs. However, the precise mechanisms by which PfMDR1 contributes to multidrug resistance have not yet been fully elucidated, nor is it understood why polymorphisms in pfmdr1 and pfcrt that cause chloroquine resistance simultaneously increase the parasite’s susceptibility to lumefantrine and mefloquine—a phenomenon known as collateral drug sensitivity. Here, we present a robust expression system for PfMDR1 in Xenopus oocytes that enables direct and high-resolution biochemical characterizations of the protein. We show that wild-type PfMDR1 transports diverse pharmacons, including lumefantrine, mefloquine, dihydroartemisinin, piperaquine, amodiaquine, methylene blue, and chloroquine (but not the antiviral drug amantadine). Field-derived mutant isoforms of PfMDR1 differ from the wild-type protein, and each other, in their capacities to transport these drugs, indicating that PfMDR1-induced changes in the distribution of drugs between the parasite’s digestive vacuole (DV) and the cytosol are a key driver of both antimalarial resistance and the variability between multidrug resistance phenotypes. Of note, the PfMDR1 isoforms prevalent in chloroquine-resistant isolates exhibit reduced capacities for chloroquine, lumefantrine, and mefloquine transport. We observe the opposite relationship between chloroquine resistance-conferring mutations in PfCRT and drug transport activity. Using our established assays for characterizing PfCRT in the Xenopus oocyte system and in live parasite assays, we demonstrate that these PfCRT isoforms transport all 3 drugs, whereas wild-type PfCRT does not. We present a mechanistic model for collateral drug sensitivity in which mutant isoforms of PfMDR1 and PfCRT cause chloroquine, lumefantrine, and mefloquine to remain in the cytosol instead of sequestering within the DV. This change in drug distribution increases the access of lumefantrine and mefloquine to their primary targets (thought to be located outside of the DV), while simultaneously decreasing chloroquine’s access to its target within the DV. The mechanistic insights presented here provide a basis for developing approaches that extend the useful life span of antimalarials by exploiting the opposing selection forces they exert upon PfCRT and PfMDR1.
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Guevara‐Pulido J, Jiménez RA, Morantes SJ, Jaramillo DN, Acosta‐Guzmán P. Design, Synthesis, and Development of 4‐[(7‐Chloroquinoline‐4‐yl)amino]phenol as a Potential SARS‐CoV‐2 Mpro Inhibitor. ChemistrySelect 2022; 7:e202200125. [PMID: 35601684 PMCID: PMC9111044 DOI: 10.1002/slct.202200125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/01/2022] [Indexed: 12/15/2022]
Abstract
A series of chloroquine analogs were designed to search for a less toxic chloroquine derivative as a potential SARS‐CoV‐2 Mpro inhibitor. Herein, an ANN‐based QSAR model was built to predict the IC50 values of each analog using the experimental values of other 4‐aminoquinolines as the training set. Subsequently, molecular docking was used to evaluate each analog's binding affinity to Mpro. The analog that showed the greatest affinity and lowest IC50 values was synthesized and characterized for its posterior incorporation into a polycaprolactone‐based nanoparticulate system. After characterizing the loaded nanoparticles, an in vitro drug release assay was carried out, and the cytotoxicity of the analog and loaded nanoparticles was evaluated using murine fibroblast (L929) and human lung adenocarcinoma (A549) cell lines. Results show that the synthesized analog is much less toxic than chloroquine and that the nanoparticulate system allowed for the prolonged release of the analog without evidence of adverse effects on the cell lines used; therefore, suggesting that the analog could be a potential therapeutic option for COVID‐19.
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Roux AT, Maharaj L, Oyegoke O, Akoniyon OP, Adeleke MA, Maharaj R, Okpeku M. Chloroquine and Sulfadoxine-Pyrimethamine Resistance in Sub-Saharan Africa-A Review. Front Genet 2021; 12:668574. [PMID: 34249090 PMCID: PMC8267899 DOI: 10.3389/fgene.2021.668574] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/20/2021] [Indexed: 12/20/2022] Open
Abstract
Malaria is a great concern for global health and accounts for a large amount of morbidity and mortality, particularly in Africa, with sub-Saharan Africa carrying the greatest burden of the disease. Malaria control tools such as insecticide-treated bed nets, indoor residual spraying, and antimalarial drugs have been relatively successful in reducing the burden of malaria; however, sub-Saharan African countries encounter great challenges, the greatest being antimalarial drug resistance. Chloroquine (CQ) was the first-line drug in the 20th century until it was replaced by sulfadoxine-pyrimethamine (SP) as a consequence of resistance. The extensive use of these antimalarials intensified the spread of resistance throughout sub-Saharan Africa, thus resulting in a loss of efficacy for the treatment of malaria. SP was replaced by artemisinin-based combination therapy (ACT) after the emergence of resistance toward SP; however, the use of ACTs is now threatened by the emergence of resistant parasites. The decreased selective pressure on CQ and SP allowed for the reintroduction of sensitivity toward those antimalarials in regions of sub-Saharan Africa where they were not the primary drug for treatment. Therefore, the emergence and spread of antimalarial drug resistance should be tracked to prevent further spread of the resistant parasites, and the re-emergence of sensitivity should be monitored to detect the possible reappearance of sensitivity in sub-Saharan Africa.
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Affiliation(s)
- Alexandra T. Roux
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville, South Africa
| | - Leah Maharaj
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville, South Africa
| | - Olukunle Oyegoke
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville, South Africa
| | - Oluwasegun P. Akoniyon
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville, South Africa
| | - Matthew Adekunle Adeleke
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville, South Africa
| | - Rajendra Maharaj
- Office of Malaria Research, South African Medical Research Council, Cape Town, South Africa
| | - Moses Okpeku
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville, South Africa
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Discovery and development of 2-aminobenzimidazoles as potent antimalarials. Eur J Med Chem 2021; 221:113518. [PMID: 34058708 DOI: 10.1016/j.ejmech.2021.113518] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 04/11/2021] [Accepted: 04/22/2021] [Indexed: 11/30/2022]
Abstract
The emergence of Plasmodium falciparum resistance to frontline antimalarials, including artemisinin combination therapies, highlights the need for new molecules that act via novel mechanisms of action. Herein, we report the design, synthesis and antimalarial activity of a series of 2-aminobenzimidazoles, featuring a phenol moiety that is crucial to the pharmacophore. Two potent molecules exhibited IC50 values against P. falciparum 3D7 strain of 42 ± 4 (3c) and 43 ± 2 nM (3g), and high potency against strains resistant to chloroquine (Dd2), artemisinin (Cam3.IIC580Y) and PfATP4 inhibitors (SJ557733), while demonstrating no cytotoxicity against human cells (HEK293, IC50 > 50 μM). The most potent molecule, possessing a 4,5-dimethyl substituted phenol (3r) displayed an IC50 value of 6.4 ± 0.5 nM against P. falciparum 3D7, representing a 12-fold increase in activity from the parent molecule. The 2-aminobenzimidazoles containing a N1-substituted phenol represent a new class of molecules that have high potency in vitro against P. falciparum malaria and low cytotoxicity. They possessed attractive pharmaceutical properties, including low molecular weight, high ligand efficiency, high solubility, synthetic tractability and low in vitro clearance in human liver microsomes.
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Ahmad SJ, Mohamad Zin N, Mazlan NW, Baharum SN, Baba MS, Lau YL. Metabolite profiling of endophytic Streptomyces spp. and its antiplasmodial potential. PeerJ 2021; 9:e10816. [PMID: 33777509 PMCID: PMC7971094 DOI: 10.7717/peerj.10816] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 12/30/2020] [Indexed: 12/20/2022] Open
Abstract
Background Antiplasmodial drug discovery is significant especially from natural sources such as plant bacteria. This research aimed to determine antiplasmodial metabolites of Streptomyces spp. against Plasmodium falciparum 3D7 by using a metabolomics approach. Methods Streptomyces strains' growth curves, namely SUK 12 and SUK 48, were measured and P. falciparum 3D7 IC50 values were calculated. Metabolomics analysis was conducted on both strains' mid-exponential and stationary phase extracts. Results The most successful antiplasmodial activity of SUK 12 and SUK 48 extracts shown to be at the stationary phase with IC50 values of 0.8168 ng/mL and 0.1963 ng/mL, respectively. In contrast, the IC50 value of chloroquine diphosphate (CQ) for antiplasmodial activity was 0.2812 ng/mL. The univariate analysis revealed that 854 metabolites and 14, 44 and three metabolites showed significant differences in terms of strain, fermentation phase, and their interactions. Orthogonal partial least square-discriminant analysis and S-loading plot putatively identified pavettine, aurantioclavine, and 4-butyldiphenylmethane as significant outliers from the stationary phase of SUK 48. For potential isolation, metabolomics approach may be used as a preliminary approach to rapidly track and identify the presence of antimalarial metabolites before any isolation and purification can be done.
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Affiliation(s)
- Siti Junaidah Ahmad
- Faculty of Health Sciences, University of Sultan Zainal Abidin, Kuala Nerus, Terengganu, Malaysia.,Center for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Noraziah Mohamad Zin
- Center for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Noor Wini Mazlan
- Analytical and Environmental Chemistry, Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, Kuala Nerus, Terengganu, Malaysia
| | | | - Mohd Shukri Baba
- Department of Biomedical Science, Kulliyyah of Allied Health Sciences, International Islamic University, Kuantan, Pahang, Malaysia
| | - Yee Ling Lau
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
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Nqoro X, Jama S, Morifi E, Aderibigbe BA. 4-Aminosalicylic Acid-based Hybrid Compounds: Synthesis and In vitro Antiplasmodial Evaluation. LETT DRUG DES DISCOV 2021. [DOI: 10.2174/1570180817999200802031547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Background:
Malaria is a deadly and infectious disease responsible for millions of death
worldwide, mostly in the African region. The malaria parasite has developed resistance to the currently
used antimalarial drugs, and it has urged researchers to develop new strategies to overcome
this challenge by designing different classes of antimalarials.
Objectives:
A class of hybrid compounds containing 4-aminosalicylic acid moiety was prepared via
esterification and amidation reactions and characterized using FTIR, NMR and LC-MS. In vitro antiplasmodial
evaluation was performed against the asexual NF54 strain of P. falciparum parasites.
Methods:
In this research, known 4-aminoquinoline derivatives were hybridized with 4-
aminosalicylic acid to afford hybrid compounds via esterification and amidation reactions. 4-
aminosalicylic acid, a dihydrofolate compound inhibits DNA synthesis in the folate pathway and is
a potential pharmacophore for the development of antimalarials.
Results:
The LC-MS, FTIR, and NMR analysis confirmed the successful synthesis of the compounds.
The compounds were obtained in yields in the range of 63-80%. The hybrid compounds
displayed significant antimalarial activity when compared to 4-aminosalicylic acid, which exhibited
poor antimalarial activity. The IC50 value of the most potent hybrid compound, 9 was 9.54±0.57 nm.
Conclusion:
4-aminosalicylic has different functionalities, which can be used for hybridization with
a wide range of compounds. It is a potential pharmacophore that can be utilized for the design of
potent antimalarial drugs. It was found to be a good potentiating agent when hybridized with 4-
aminoquinoline derivatives suggesting that they can be utilized for the synthesis of a new class of
antimalarials.
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Affiliation(s)
- Xhamla Nqoro
- Department of Chemistry, University of Fort Hare, Alice Campus,South Africa
| | - Siphesihle Jama
- Department of Chemistry, University of Fort Hare, Alice Campus,South Africa
| | - Eric Morifi
- School of Chemistry, Mass Spectrometry Division, University of the Witwatersrand, Johannesburg Private Bag X3, WITS, 2050,South Africa
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Martin RE. The transportome of the malaria parasite. Biol Rev Camb Philos Soc 2019; 95:305-332. [PMID: 31701663 DOI: 10.1111/brv.12565] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 10/02/2019] [Accepted: 10/04/2019] [Indexed: 12/15/2022]
Abstract
Membrane transport proteins, also known as transporters, control the movement of ions, nutrients, metabolites, and waste products across the membranes of a cell and are central to its biology. Proteins of this type also serve as drug targets and are key players in the phenomenon of drug resistance. The malaria parasite has a relatively reduced transportome, with only approximately 2.5% of its genes encoding transporters. Even so, assigning functions and physiological roles to these proteins, and ascertaining their contributions to drug action and drug resistance, has been very challenging. This review presents a detailed critique and synthesis of the disruption phenotypes, protein subcellular localisations, protein functions (observed or predicted), and links to antimalarial drug resistance for each of the parasite's transporter genes. The breadth and depth of the gene disruption data are particularly impressive, with at least one phenotype determined in the parasite's asexual blood stage for each transporter gene, and multiple phenotypes available for 76% of the genes. Analysis of the curated data set revealed there to be relatively little redundancy in the Plasmodium transportome; almost two-thirds of the parasite's transporter genes are essential or required for normal growth in the asexual blood stage of the parasite, and this proportion increased to 78% when the disruption phenotypes available for the other parasite life stages were included in the analysis. These observations, together with the finding that 22% of the transportome is implicated in the parasite's resistance to existing antimalarials and/or drugs within the development pipeline, indicate that transporters are likely to serve, or are already serving, as drug targets. Integration of the different biological and bioinformatic data sets also enabled the selection of candidates for transport processes known to be essential for parasite survival, but for which the underlying proteins have thus far remained undiscovered. These include potential transporters of pantothenate, isoleucine, or isopentenyl diphosphate, as well as putative anion-selective channels that may serve as the pore component of the parasite's 'new permeation pathways'. Other novel insights into the parasite's biology included the identification of transporters for the potential development of antimalarial treatments, transmission-blocking drugs, prophylactics, and genetically attenuated vaccines. The syntheses presented herein set a foundation for elucidating the functions and physiological roles of key members of the Plasmodium transportome and, ultimately, to explore and realise their potential as therapeutic targets.
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Affiliation(s)
- Rowena E Martin
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
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A Variant PfCRT Isoform Can Contribute to Plasmodium falciparum Resistance to the First-Line Partner Drug Piperaquine. mBio 2017; 8:mBio.00303-17. [PMID: 28487425 PMCID: PMC5424201 DOI: 10.1128/mbio.00303-17] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Current efforts to reduce the global burden of malaria are threatened by the rapid spread throughout Asia of Plasmodium falciparum resistance to artemisinin-based combination therapies, which includes increasing rates of clinical failure with dihydroartemisinin plus piperaquine (PPQ) in Cambodia. Using zinc finger nuclease-based gene editing, we report that addition of the C101F mutation to the chloroquine (CQ) resistance-conferring PfCRT Dd2 isoform common to Asia can confer PPQ resistance to cultured parasites. Resistance was demonstrated as significantly higher PPQ concentrations causing 90% inhibition of parasite growth (IC90) or 50% parasite killing (50% lethal dose [LD50]). This mutation also reversed Dd2-mediated CQ resistance, sensitized parasites to amodiaquine, quinine, and artemisinin, and conferred amantadine and blasticidin resistance. Using heme fractionation assays, we demonstrate that PPQ causes a buildup of reactive free heme and inhibits the formation of chemically inert hemozoin crystals. Our data evoke inhibition of heme detoxification in the parasite’s acidic digestive vacuole as the primary mode of both the bis-aminoquinoline PPQ and the related 4-aminoquinoline CQ. Both drugs also inhibit hemoglobin proteolysis at elevated concentrations, suggesting an additional mode of action. Isogenic lines differing in their pfmdr1 copy number showed equivalent PPQ susceptibilities. We propose that mutations in PfCRT could contribute to a multifactorial basis of PPQ resistance in field isolates. The global agenda to eliminate malaria depends on the continued success of artemisinin-based combination therapies (ACTs), which target the asexual blood stages of the intracellular parasite Plasmodium. Partial resistance to artemisinin, however, is now established in Southeast Asia, exposing the partner drugs to increased selective pressure. Plasmodium falciparum resistance to the first-line partner piperaquine (PPQ) is now spreading rapidly in Cambodia, resulting in clinical treatment failures. Here, we report that a variant form of the Plasmodium falciparum chloroquine resistance transporter, harboring a C101F mutation edited into the chloroquine (CQ)-resistant Dd2 isoform prevalent in Asia, can confer PPQ resistance in cultured parasites. This was accompanied by a loss of CQ resistance. Biochemical assays showed that PPQ, like CQ, inhibits the detoxification of reactive heme that is formed by parasite-mediated catabolism of host hemoglobin. We propose that novel PfCRT variants emerging in the field could contribute to a multigenic basis of PPQ resistance.
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Influence of LAR and VAR on Para-Aminopyridine Antimalarials Targetting Haematin in Chloroquine-Resistance. PLoS One 2016; 11:e0160091. [PMID: 27483471 PMCID: PMC4970729 DOI: 10.1371/journal.pone.0160091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 07/13/2016] [Indexed: 11/23/2022] Open
Abstract
Antimalarial chloroquine (CQ) prevents haematin detoxication when CQ-base concentrates in the acidic digestive vacuole through protonation of its p-aminopyridine (pAP) basic aromatic nitrogen and sidechain diethyl-N. CQ export through the variant vacuolar membrane export channel, PFCRT, causes CQ-resistance in Plasmodium falciparum but 3-methyl CQ (sontochin SC), des-ethyl amodiaquine (DAQ) and bis 4-aminoquinoline piperaquine (PQ) are still active. This is determined by changes in drug accumulation ratios in parasite lipid (LAR) and in vacuolar water (VAR). Higher LAR may facilitate drug binding to and blocking PFCRT and also aid haematin in lipid to bind drug. LAR for CQ is only 8.3; VAR is 143,482. More hydrophobic SC has LAR 143; VAR remains 68,523. Similarly DAQ with a phenol substituent has LAR of 40.8, with VAR 89,366. In PQ, basicity of each pAP is reduced by distal piperazine N, allowing very high LAR of 973,492, retaining VAR of 104,378. In another bis quinoline, dichlorquinazine (DCQ), also active but clinically unsatisfactory, each pAP retains basicity, being insulated by a 2-carbon chain from a proximal nitrogen of the single linking piperazine. While LAR of 15,488 is still high, the lowest estimate of VAR approaches 4.9 million. DCQ may be expected to be very highly lysosomotropic and therefore potentially hepatotoxic. In 11 pAP antimalarials a quadratic relationship between logLAR and logResistance Index (RI) was confirmed, while log (LAR/VAR) vs logRI for 12 was linear. Both might be used to predict the utility of structural modifications.
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Richards SN, Nash MN, Baker ES, Webster MW, Lehane AM, Shafik SH, Martin RE. Molecular Mechanisms for Drug Hypersensitivity Induced by the Malaria Parasite's Chloroquine Resistance Transporter. PLoS Pathog 2016; 12:e1005725. [PMID: 27441371 PMCID: PMC4956231 DOI: 10.1371/journal.ppat.1005725] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 06/03/2016] [Indexed: 01/23/2023] Open
Abstract
Mutations in the Plasmodium falciparum ‘chloroquine resistance transporter’ (PfCRT) confer resistance to chloroquine (CQ) and related antimalarials by enabling the protein to transport these drugs away from their targets within the parasite’s digestive vacuole (DV). However, CQ resistance-conferring isoforms of PfCRT (PfCRTCQR) also render the parasite hypersensitive to a subset of structurally-diverse pharmacons. Moreover, mutations in PfCRTCQR that suppress the parasite’s hypersensitivity to these molecules simultaneously reinstate its sensitivity to CQ and related drugs. We sought to understand these phenomena by characterizing the functions of PfCRTCQR isoforms that cause the parasite to become hypersensitive to the antimalarial quinine or the antiviral amantadine. We achieved this by measuring the abilities of these proteins to transport CQ, quinine, and amantadine when expressed in Xenopus oocytes and complemented this work with assays that detect the drug transport activity of PfCRT in its native environment within the parasite. Here we describe two mechanistic explanations for PfCRT-induced drug hypersensitivity. First, we show that quinine, which normally accumulates inside the DV and therewithin exerts its antimalarial effect, binds extremely tightly to the substrate-binding site of certain isoforms of PfCRTCQR. By doing so it likely blocks the normal physiological function of the protein, which is essential for the parasite’s survival, and the drug thereby gains an additional killing effect. In the second scenario, we show that although amantadine also sequesters within the DV, the parasite’s hypersensitivity to this drug arises from the PfCRTCQR-mediated transport of amantadine from the DV into the cytosol, where it can better access its antimalarial target. In both cases, the mutations that suppress hypersensitivity also abrogate the ability of PfCRTCQR to transport CQ, thus explaining why rescue from hypersensitivity restores the parasite’s sensitivity to this antimalarial. These insights provide a foundation for understanding clinically-relevant observations of inverse drug susceptibilities in the malaria parasite. In acquiring resistance to one drug, many pathogens and cancer cells become hypersensitive to other drugs. This phenomenon could be exploited to combat existing drug resistance and to delay the emergence of resistance to new drugs. However, much remains to be understood about the mechanisms that underlie drug hypersensitivity in otherwise drug-resistant microbes. Here, we describe two mechanisms by which the Plasmodium falciparum ‘chloroquine resistance transporter’ (PfCRT) causes the malaria parasite to become hypersensitive to structurally-diverse drugs. First, we show that an antimalarial drug that normally exerts its killing effect within the parasite’s digestive vacuole is also able to bind extremely tightly to certain forms of PfCRT. This activity will block the natural, essential function of the protein and thereby provide the drug with an additional killing effect. The second mechanism arises when a cytosolic-acting drug that normally sequesters within the digestive vacuole is leaked back into the cytosol via PfCRT. In both cases, mutations that suppress hypersensitivity also abrogate the ability of PfCRT to transport chloroquine, thus explaining why rescue from hypersensitivity restores the parasite’s sensitivity to this antimalarial. These insights provide a foundation for understanding and exploiting the hypersensitivity of chloroquine-resistant parasites to several of the current antimalarials.
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Affiliation(s)
- Sashika N. Richards
- Research School of Biology, Australian National University, Canberra, Australia
| | - Megan N. Nash
- Research School of Biology, Australian National University, Canberra, Australia
| | - Eileen S. Baker
- Research School of Biology, Australian National University, Canberra, Australia
| | - Michael W. Webster
- Research School of Biology, Australian National University, Canberra, Australia
| | - Adele M. Lehane
- Research School of Biology, Australian National University, Canberra, Australia
| | - Sarah H. Shafik
- Research School of Biology, Australian National University, Canberra, Australia
| | - Rowena E. Martin
- Research School of Biology, Australian National University, Canberra, Australia
- * E-mail:
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Pulcini S, Staines HM, Lee AH, Shafik SH, Bouyer G, Moore CM, Daley DA, Hoke MJ, Altenhofen LM, Painter HJ, Mu J, Ferguson DJP, Llinás M, Martin RE, Fidock DA, Cooper RA, Krishna S. Mutations in the Plasmodium falciparum chloroquine resistance transporter, PfCRT, enlarge the parasite's food vacuole and alter drug sensitivities. Sci Rep 2015; 5:14552. [PMID: 26420308 PMCID: PMC4588581 DOI: 10.1038/srep14552] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/14/2015] [Indexed: 12/30/2022] Open
Abstract
Mutations in the Plasmodium falciparum chloroquine resistance transporter, PfCRT, are the major determinant of chloroquine resistance in this lethal human malaria parasite. Here, we describe P. falciparum lines subjected to selection by amantadine or blasticidin that carry PfCRT mutations (C101F or L272F), causing the development of enlarged food vacuoles. These parasites also have increased sensitivity to chloroquine and some other quinoline antimalarials, but exhibit no or minimal change in sensitivity to artemisinins, when compared with parental strains. A transgenic parasite line expressing the L272F variant of PfCRT confirmed this increased chloroquine sensitivity and enlarged food vacuole phenotype. Furthermore, the introduction of the C101F or L272F mutation into a chloroquine-resistant variant of PfCRT reduced the ability of this protein to transport chloroquine by approximately 93 and 82%, respectively, when expressed in Xenopus oocytes. These data provide, at least in part, a mechanistic explanation for the increased sensitivity of the mutant parasite lines to chloroquine. Taken together, these findings provide new insights into PfCRT function and PfCRT-mediated drug resistance, as well as the food vacuole, which is an important target of many antimalarial drugs.
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Affiliation(s)
- Serena Pulcini
- Institute for Infection and Immunity, St. George's, University of London, London SW17 0RE, UK
| | - Henry M Staines
- Institute for Infection and Immunity, St. George's, University of London, London SW17 0RE, UK
| | - Andrew H Lee
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA
| | - Sarah H Shafik
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Guillaume Bouyer
- Institute for Infection and Immunity, St. George's, University of London, London SW17 0RE, UK.,Sorbonne Universités, UPMC Univ. Paris 06, UMR 8227, Integrative Biology of Marine Models, Comparative Physiology of Erythrocytes, Station Biologique de Roscoff, Roscoff, France.,CNRS, UMR 8227, Integrative Biology of Marine Models, Comparative Physiology of Erythrocytes, Station Biologique de Roscoff, Roscoff, France
| | - Catherine M Moore
- Institute for Infection and Immunity, St. George's, University of London, London SW17 0RE, UK
| | - Daniel A Daley
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA
| | - Matthew J Hoke
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA
| | - Lindsey M Altenhofen
- Department of Biochemistry and Molecular Biology and Center for Malaria Research, Pennsylvania State University, State College, Pennsylvania 16802, USA
| | - Heather J Painter
- Department of Biochemistry and Molecular Biology and Center for Malaria Research, Pennsylvania State University, State College, Pennsylvania 16802, USA
| | - Jianbing Mu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville MD 20852, USA
| | - David J P Ferguson
- Nuffield Department of Clinical Laboratory Sciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Manuel Llinás
- Department of Biochemistry and Molecular Biology and Center for Malaria Research, Pennsylvania State University, State College, Pennsylvania 16802, USA
| | - Rowena E Martin
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA.,Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, NY 10032, USA
| | - Roland A Cooper
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA.,Department of Natural Sciences and Mathematics, Dominican University of California, San Rafael, CA 94901, USA
| | - Sanjeev Krishna
- Institute for Infection and Immunity, St. George's, University of London, London SW17 0RE, UK
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13
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Role of Different Pfcrt and Pfmdr-1 Mutations in Conferring Resistance to Antimalaria Drugs in Plasmodium falciparum. Malar Res Treat 2014; 2014:950424. [PMID: 25506039 PMCID: PMC4243603 DOI: 10.1155/2014/950424] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Accepted: 08/30/2014] [Indexed: 01/28/2023] Open
Abstract
Emergence of drugs resistant strains of Plasmodium falciparum has augmented the scourge of malaria in endemic areas. Antimalaria drugs act on different intracellular targets. The majority of them interfere with digestive vacuoles (DVs) while others affect other organelles, namely, apicoplast and mitochondria. Prevention of drug accumulation or access into the target site is one of the mechanisms that plasmodium adopts to develop resistance. Plasmodia are endowed with series of transporters that shuffle drugs away from the target site, namely, pfmdr (Plasmodium falciparum multidrug resistance transporter) and pfcrt (Plasmodium falciparum chloroquine resistance transporter) which exist in DV membrane and are considered as putative markers of CQ resistance. They are homologues to human P-glycoproteins (P-gh or multidrug resistance system) and members of drug metabolite transporter (DMT) family, respectively. The former mediates drifting of xenobiotics towards the DV while the latter chucks them outside. Resistance to drugs whose target site of action is intravacuolar develops when the transporters expel them outside the DVs and vice versa for those whose target is extravacuolar. In this review, we are going to summarize the possible pfcrt and pfmdr mutation and their role in changing plasmodium sensitivity to different anti-Plasmodium drugs.
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14
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Jonet A, Dassonville-Klimpt A, Sonnet P, Mullié C. Side chain length is more important than stereochemistry in the antibacterial activity of enantiomerically pure 4-aminoalcohol quinoline derivatives. J Antibiot (Tokyo) 2013; 66:683-6. [PMID: 23820616 DOI: 10.1038/ja.2013.71] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 05/28/2013] [Accepted: 05/29/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Alexia Jonet
- Laboratoire des Glucides FRE-CNRS 3517, Equipe Théra, Faculté de Pharmacie, Amiens, France
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15
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Dassonville-Klimpt A, Cézard C, Mullié C, Agnamey P, Jonet A, Da Nascimento S, Marchivie M, Guillon J, Sonnet P. Absolute Configuration and Antimalarial Activity of erythro-Mefloquine Enantiomers. Chempluschem 2013; 78:642-646. [PMID: 31986621 DOI: 10.1002/cplu.201300074] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 06/17/2013] [Indexed: 11/11/2022]
Abstract
Mefloquine (MQ), an antimalarial drug, is used as a racemate of (-)- and (+)-enantiomers, which display biological differences. The question concerning their exact configuration remains a matter of debate. The absolute configuration of the two MQ enantiomers as well as their biological activity has been established, thus confirming the importance of the stereochemistry in the design of MQ analogues that have fewer adverse side effects.
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Affiliation(s)
- Alexandra Dassonville-Klimpt
- Laboratoire des Glucides, CNRS FRE 3517, UFR de Pharmacie, Université de Picardie Jules Verne, 1, rue des Louvels, 80037 Amiens cedex 01 (France), Fax: (+33) 322827469
| | - Christine Cézard
- Laboratoire des Glucides, CNRS FRE 3517, UFR de Pharmacie, Université de Picardie Jules Verne, 1, rue des Louvels, 80037 Amiens cedex 01 (France), Fax: (+33) 322827469
| | - Catherine Mullié
- Laboratoire des Glucides, CNRS FRE 3517, UFR de Pharmacie, Université de Picardie Jules Verne, 1, rue des Louvels, 80037 Amiens cedex 01 (France), Fax: (+33) 322827469
| | - Patrice Agnamey
- Laboratoire des Glucides, CNRS FRE 3517, UFR de Pharmacie, Université de Picardie Jules Verne, 1, rue des Louvels, 80037 Amiens cedex 01 (France), Fax: (+33) 322827469
| | - Alexia Jonet
- Laboratoire des Glucides, CNRS FRE 3517, UFR de Pharmacie, Université de Picardie Jules Verne, 1, rue des Louvels, 80037 Amiens cedex 01 (France), Fax: (+33) 322827469
| | - Sophie Da Nascimento
- Laboratoire des Glucides, CNRS FRE 3517, UFR de Pharmacie, Université de Picardie Jules Verne, 1, rue des Louvels, 80037 Amiens cedex 01 (France), Fax: (+33) 322827469
| | - Mathieu Marchivie
- CNRS FRE 3396-Pharmacochimie, UFR de Pharmacie, Université Bordeaux Segalen, 33076 Bordeaux cedex (France)
| | - Jean Guillon
- CNRS FRE 3396-Pharmacochimie, UFR de Pharmacie, Université Bordeaux Segalen, 33076 Bordeaux cedex (France)
| | - Pascal Sonnet
- Laboratoire des Glucides, CNRS FRE 3517, UFR de Pharmacie, Université de Picardie Jules Verne, 1, rue des Louvels, 80037 Amiens cedex 01 (France), Fax: (+33) 322827469
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Gorka AP, de Dios A, Roepe PD. Quinoline drug-heme interactions and implications for antimalarial cytostatic versus cytocidal activities. J Med Chem 2013; 56:5231-46. [PMID: 23586757 DOI: 10.1021/jm400282d] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Historically, the most successful molecular target for antimalarial drugs has been heme biomineralization within the malarial parasite digestive vacuole. Heme released from catabolized host red blood cell hemoglobin is toxic, so malarial parasites crystallize heme to nontoxic hemozoin. For years it has been accepted that a number of effective quinoline antimalarial drugs (e.g., chloroquine, quinine, amodiaquine) function by preventing hemozoin crystallization. However, recent studies over the past decade have revealed a surprising molecular diversity in quinoline-heme molecular interactions. This diversity shows that even closely related quinoline drugs may have quite different molecular pharmacology. This paper reviews the molecular diversity and highlights important implications for understanding quinoline antimalarial drug resistance and for future drug design.
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Affiliation(s)
- Alexander P Gorka
- Department of Chemistry, Department of Biochemistry, Cellular, and Molecular Biology, and Center for Infectious Diseases, Georgetown University , 37th and O Streets, NW, Washington, D.C. 20057, United States
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17
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Relative to quinine and quinidine, their 9-epimers exhibit decreased cytostatic activity and altered heme binding but similar cytocidal activity versus Plasmodium falciparum. Antimicrob Agents Chemother 2012; 57:365-74. [PMID: 23114754 DOI: 10.1128/aac.01234-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 9-epimers of quinine (QN) and quinidine (QD) are known to exhibit poor cytostatic potency against P. falciparum (Karle JM, Karle IL, Gerena L, Milhous WK, Antimicrob. Agents Chemother. 36:1538-1544, 1992). We synthesized 9-epi-QN (eQN) and 9-epi-QD (eQD) via Mitsunobu esterification-saponification and evaluated both cytostatic and cytocidal antimalarial activities. Relative to the cytostatic activity of QN and QD, we observed a large decrease in cytostatic activity (higher 50% inhibitory concentration [IC(50)s]) against QN-sensitive strain HB3, QN-resistant strain Dd2, and QN-hypersensitive strain K76I, consistent with previous work. However, we observed relatively small changes in cytocidal activity (the 50% lethal dose), similar to observations with chloroquine (CQ) analogues with a wide range of IC(50)s (see the accompanying paper [A. P. Gorka, J. N. Alumasa, K. S. Sherlach, L. M. Jacobs, K. B. Nickley, J. P. Brower, A. C. de Dios, and P. D. Roepe, Antimicrob. Agents Chemother. 57:356-364, 2013]). Compared to QN and QD, the 9-epimers had significantly reduced hemozoin inhibition efficiency and did not affect pH-dependent aggregation of ferriprotoporphyrin IX (FPIX) heme. Magnetic susceptibility measurements showed that the 9-epimers perturb FPIX monomer-dimer equilibrium in favor of monomer, and UV-visible (VIS) titrations showed that eQN and eQD bind monomer with similar affinity relative to QN and QD. However, unique ring proton shifts in the presence of zinc(II) protoporphyrin IX (ZnPIX) indicate that binding of the 9-epimers to monomeric heme is via a distinct geometry. We isolated eQN- and eQD-FPIX complexes formed under aqueous conditions and analyzed them by mass, fluorescence, and UV-VIS spectroscopies. The 9-epimers produced low-fluorescent adducts with a 2:1 stoichiometry (drug to FPIX) which did not survive electrospray ionization, in contrast to QN and QD complexes. The data offer important insight into the relevance of heme interactions as a drug target for cytostatic versus cytocidal dosages of quinoline antimalarial drugs and further elucidate a surprising structural diversity of quinoline antimalarial drug-heme complexes.
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18
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Ecker A, Lewis RE, Ekland EH, Jayabalasingham B, Fidock DA. Tricks in Plasmodium's molecular repertoire--escaping 3'UTR excision-based conditional silencing of the chloroquine resistance transporter gene. Int J Parasitol 2012; 42:969-74. [PMID: 23023047 DOI: 10.1016/j.ijpara.2012.09.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2012] [Revised: 08/18/2012] [Accepted: 09/17/2012] [Indexed: 11/25/2022]
Abstract
In the human malaria parasite Plasmodium falciparum, the major determinant of chloroquine resistance, P. falciparum chloroquine resistance transporter (pfcrt), likely plays an essential role in asexual blood stages, thus precluding conventional gene targeting approaches. We attempted to conditionally silence the expression of its ortholog in Plasmodium berghei (pbcrt) through Flp recombinase-mediated excision of the 3'untranslated region (UTR) during mosquito passage. However, parasites maintained pbcrt expression despite 3'UTR excision. Characterisation of these pbcrt mRNAs, by 3'rapid amplification of cDNA ends, identified several replacement 3'UTR sequences. Our observations demonstrate the astounding genetic plasticity of this parasite when faced with the loss of an essential gene.
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Affiliation(s)
- Andrea Ecker
- Department of Microbiology and Immunology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
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