26
|
Espinoza-Moraga M, Singh K, Njoroge M, Kaur G, Okombo J, De Kock C, Smith PJ, Wittlin S, Chibale K. Synthesis and biological characterisation of ester and amide derivatives of fusidic acid as antiplasmodial agents. Bioorg Med Chem Lett 2017; 27:658-661. [DOI: 10.1016/j.bmcl.2016.11.077] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 11/23/2016] [Accepted: 11/24/2016] [Indexed: 11/16/2022]
|
27
|
Cavallo AV, Smith PJ, Morley S, Morsi AW. Non-Vascularized Free Toe Phalanx Transfers in Congenital Hand Deformities – the Great Ormond Street Experience. ACTA ACUST UNITED AC 2017; 28:520-7. [PMID: 14599822 DOI: 10.1016/s0266-7681(03)00084-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Many options of varying complexity are available for the management of congenital short digits resulting from aphalangia in symbrachydactyly and constriction ring syndrome. We have used non-vascularized free toe phalanx transfers for these children when a vascularized toe transfer has been contraindicated. We describe our technique and experience with 22 children who underwent a total of 64 transfers of the proximal (35) or middle (29) toe phalanges (average 3 per child). The mean age at initial surgery was 15 months, and the mean follow-up was 5 years. Duration of time until epiphyseal closure could not be determined accurately, but total digital elongation averaged 6 mm. Complications of this technique include joint instability, premature epiphyseal closure and, in one patient, infection and graft loss. Donor site deformity was determined according to measured growth deficit and toe function. This technique is a simple option for digital elongation and, if performed in the appropriate age group in short fingered and monodactylous subtypes of symbrachydactyly, has the potential to allow growth and function with minimal donor site deficit.
Collapse
|
28
|
Stringer T, Seldon R, Liu N, Warner DF, Tam C, Cheng LW, Land KM, Smith PJ, Chibale K, Smith GS. Antimicrobial activity of organometallic isonicotinyl and pyrazinyl ferrocenyl-derived complexes. Dalton Trans 2017; 46:9875-9885. [DOI: 10.1039/c7dt01952a] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Isonicotinyl and pyrazinyl ferrocenyl-derived complexes were evaluatedin vitrofor antimycobacterial and antiparasitic activity.
Collapse
|
29
|
Smith PJ, Wang HT, York WS, Peña MJ, Urbanowicz BR. Designer biomass for next-generation biorefineries: leveraging recent insights into xylan structure and biosynthesis. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:286. [PMID: 29213325 PMCID: PMC5708106 DOI: 10.1186/s13068-017-0973-z] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/20/2017] [Indexed: 05/02/2023]
Abstract
Xylans are the most abundant noncellulosic polysaccharides in lignified secondary cell walls of woody dicots and in both primary and secondary cell walls of grasses. These polysaccharides, which comprise 20-35% of terrestrial biomass, present major challenges for the efficient microbial bioconversion of lignocellulosic feedstocks to fuels and other value-added products. Xylans play a significant role in the recalcitrance of biomass to degradation, and their bioconversion requires metabolic pathways that are distinct from those used to metabolize cellulose. In this review, we discuss the key differences in the structural features of xylans across diverse plant species, how these features affect their interactions with cellulose and lignin, and recent developments in understanding their biosynthesis. In particular, we focus on how the combined structural and biosynthetic knowledge can be used as a basis for biomass engineering aimed at developing crops that are better suited as feedstocks for the bioconversion industry.
Collapse
|
30
|
Adams M, de Kock C, Smith PJ, Chibale K, Smith GS. Evaluation of Ferrocenyl-Containing Benzothiazoles as Potential Antiplasmodial Agents. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201601000] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
31
|
Zuma NH, Smit FJ, de Kock C, Combrinck J, Smith PJ, N'Da DD. Synthesis and biological evaluation of a series of non-hemiacetal ester derivatives of artemisinin. Eur J Med Chem 2016; 122:635-646. [DOI: 10.1016/j.ejmech.2016.07.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 07/11/2016] [Accepted: 07/12/2016] [Indexed: 01/31/2023]
|
32
|
Baartzes N, Stringer T, Okombo J, Seldon R, Warner DF, de Kock C, Smith PJ, Smith GS. Mono- and polynuclear ferrocenylthiosemicarbazones: Synthesis, characterisation and antimicrobial evaluation. J Organomet Chem 2016. [DOI: 10.1016/j.jorganchem.2016.06.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
33
|
Smith PJ, Blumenthal JA. Response to "Does Sleep Play a Role in the Relationship Among Depression, Anxiety, and Mortality in Lung Transplanted Patients?". Am J Transplant 2016; 16:2495. [PMID: 27105775 DOI: 10.1111/ajt.13836] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
|
34
|
Smith PJ, Steadman KJ. Antioxidant supplementation and cancer patients receiving curative-intent chemotherapy. Med J Aust 2016; 204:185-185e1. [PMID: 26985844 DOI: 10.5694/mja15.01196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 12/11/2015] [Indexed: 11/17/2022]
|
35
|
Wicht KJ, Combrinck JM, Smith PJ, Hunter R, Egan TJ. Identification and SAR Evaluation of Hemozoin-Inhibiting Benzamides Active against Plasmodium falciparum. J Med Chem 2016; 59:6512-30. [PMID: 27299916 DOI: 10.1021/acs.jmedchem.6b00719] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Quinoline antimalarials target hemozoin formation causing a cytotoxic accumulation of ferriprotoporphyrin IX (Fe(III)PPIX). Well-developed SAR models exist for β-hematin inhibition, parasite activity, and cellular mechanisms for this compound class, but no comparably detailed investigations exist for other hemozoin inhibiting chemotypes. Here, benzamide analogues based on previous HTS hits have been purchased or synthesized. Only derivatives containing an electron deficient aromatic ring and capable of adopting flat conformations, optimal for π-π interactions with Fe(III)PPIX, inhibited β-hematin formation. The two most potent analogues showed nanomolar parasite activity, with little CQ cross-resistance, low cytotoxicity, and high in vitro microsomal stability. Selected analogues inhibited hemozoin formation in Plasmodium falciparum causing high levels of free heme. In contrast to quinolines, introduction of amine side chains did not lead to benzamide accumulation in the parasite. These data reveal complex relationships between heme binding, free heme levels, cellular accumulation, and in vitro activity of potential novel antimalarials.
Collapse
|
36
|
Ta VD, Carter RM, Esenturk E, Connaughton C, Wasley TJ, Li J, Kay RW, Stringer J, Smith PJ, Shephard JD. Dynamically controlled deposition of colloidal nanoparticle suspension in evaporating drops using laser radiation. SOFT MATTER 2016; 12:4530-6. [PMID: 27094902 DOI: 10.1039/c6sm00465b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Dynamic control of the distribution of polystyrene suspended nanoparticles in evaporating droplets is investigated using a 2.9 μm high power laser. Under laser radiation a droplet is locally heated and fluid flows are induced that overcome the capillary flow, and thus a reversal of the coffee-stain effect is observed. Suspension particles are accumulated in a localised area, one order of magnitude smaller than the original droplet size. By scanning the laser beam over the droplet, particles can be deposited in an arbitrary pattern. This finding raises the possibility for direct laser writing of suspended particles through a liquid layer. Furthermore, a highly uniform coating is possible by manipulating the laser beam diameter and exposure time. The effect is expected to be universally applicable to aqueous solutions independent of solutes (either particles or molecules) and deposited substrates.
Collapse
|
37
|
Baartzes N, Stringer T, Chellan P, Combrinck JM, Smith PJ, Hutton AT, Smith GS. Synthesis, characterization, antiplasmodial evaluation and electrochemical studies of water-soluble heterobimetallic ferrocenyl complexes. Inorganica Chim Acta 2016. [DOI: 10.1016/j.ica.2016.02.058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
38
|
Smith PJ, Clavarino AM, Long JE, Anstey CM, Steadman KJ. Complementary and alternative medicine use by patients receiving curative-intent chemotherapy. Asia Pac J Clin Oncol 2016; 12:265-74. [DOI: 10.1111/ajco.12490] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/20/2016] [Indexed: 11/28/2022]
|
39
|
Smith PJ. Commentary: Old Perceptions Were Too Limited. INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2016; 54:81-82. [PMID: 27028248 DOI: 10.1352/1934-9556-54.2.81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
|
40
|
Blackie MA, Feng TS, Smith PJ, Chibale K. Synthesis of novel β-lactams and in vitro evaluation against the human malaria parasite Plasmodium falciparum. ARKIVOC 2016. [DOI: 10.3998/ark.5550190.p009.465] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
41
|
Abstract
Cognitive decline is an increasingly important public health problem, with more than 100 million adults worldwide projected to develop dementia by 2050. Accordingly, there has been an increased interest in preventive strategies that diminish this risk. It has been recognized that lifestyle factors including dietary patterns, may be important in the prevention of cognitive decline and dementia in later life. Several dietary components have been examined, including antioxidants, fatty acids, and B vitamins. In addition, whole dietary eating plans, including the Mediterranean diet (MeDi), and the Dietary Approaches to Stop Hypertension (DASH) diet, with and without weight loss, have become areas of increasing interest. Although prospective epidemiological studies have observed that antioxidants, fatty acids, and B vitamins are associated with better cognitive functioning, randomized clinical trials have generally failed to confirm the value of any specific dietary component in improving neurocognition. Several randomized trials have examined the impact of changing 'whole' diets on cognitive outcomes. The MeDi and DASH diets offer promising preliminary results, but data are limited and more research in this area is needed.
Collapse
|
42
|
Joubert J, Kapp E, Taylor D, Smith PJ, Malan SF. Polycyclic amines as chloroquine resistance modulating agents in Plasmodium falciparum. Bioorg Med Chem Lett 2016; 26:1151-5. [DOI: 10.1016/j.bmcl.2016.01.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/15/2016] [Accepted: 01/18/2016] [Indexed: 10/22/2022]
|
43
|
Kredo T, Mauff K, Workman L, Van der Walt JS, Wiesner L, Smith PJ, Maartens G, Cohen K, Barnes KI. The interaction between artemether-lumefantrine and lopinavir/ritonavir-based antiretroviral therapy in HIV-1 infected patients. BMC Infect Dis 2016; 16:30. [PMID: 26818566 PMCID: PMC4728832 DOI: 10.1186/s12879-016-1345-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 01/12/2016] [Indexed: 12/16/2022] Open
Abstract
Background Artemether-lumefantrine is currently the most widely recommended treatment of uncomplicated malaria. Lopinavir–based antiretroviral therapy is the commonly recommended second-line HIV treatment. Artemether and lumefantrine are metabolised by cytochrome P450 isoenzyme CYP3A4, which lopinavir/ritonavir inhibits, potentially causing clinically important drug-drug interactions. Methods An adaptive, parallel-design safety and pharmacokinetic study was conducted in HIV-infected (malaria-negative) patients: antiretroviral-naïve and those stable on lopinavir/ritonavir-based antiretrovirals. Both groups received the recommended six-dose artemether-lumefantrine treatment. The primary outcome was day-7 lumefantrine concentrations, as these correlate with antimalarial efficacy. Adverse events were solicited throughout the study, recording the onset, duration, severity, and relationship to artemether-lumefantrine. Results We enrolled 34 patients. Median day-7 lumefantrine concentrations were almost 10-fold higher in the lopinavir than the antiretroviral-naïve group [3170 versus 336 ng/mL; p = 0.0001], with AUC(0-inf) and Cmax increased five-fold [2478 versus 445 μg.h/mL; p = 0.0001], and three-fold [28.2 versus 8.8 μg/mL; p < 0.0001], respectively. Lumefantrine Cmax, and AUC(0-inf) increased significantly with mg/kg dose in the lopinavir, but not the antiretroviral-naïve group. While artemether exposure was similar between groups, Cmax and AUC(0-8h) of its active metabolite dihydroartemisinin were initially two-fold higher in the lopinavir group [p = 0.004 and p = 0.0013, respectively]. However, this difference was no longer apparent after the last artemether-lumefantrine dose. Within 21 days of starting artemether-lumefantrine there were similar numbers of treatment emergent adverse events (42 vs. 35) and adverse reactions (12 vs. 15, p = 0.21) in the lopinavir and antiretroviral-naïve groups, respectively. There were no serious adverse events and no difference in electrocardiographic QTcF- and PR-intervals, at the predicted lumefantrine Tmax. Conclusion Despite substantially higher lumefantrine exposure, intensive monitoring in our relatively small study raised no safety concerns in HIV-infected patients stable on lopinavir-based antiretroviral therapy given the recommended artemether-lumefantrine dosage. Increased day-7 lumefantrine concentrations have been shown previously to reduce the risk of malaria treatment failure, but further evidence in adult patients co-infected with malaria and HIV is needed to assess the artemether-lumefantrine risk : benefit profile in this vulnerable population fully. Our antiretroviral-naïve patients confirmed previous findings that lumefantrine absorption is almost saturated at currently recommended doses, but this dose-limited absorption was overcome in the lopinavir group. Trial registration Clinical Trial Registration number NCT00869700. Registered on clinicaltrials.gov 25 March 2009 Electronic supplementary material The online version of this article (doi:10.1186/s12879-016-1345-1) contains supplementary material, which is available to authorized users.
Collapse
|
44
|
Swart M, Evans J, Skelton M, Castel S, Wiesner L, Smith PJ, Dandara C. An Expanded Analysis of Pharmacogenetics Determinants of Efavirenz Response that Includes 3'-UTR Single Nucleotide Polymorphisms among Black South African HIV/AIDS Patients. Front Genet 2016; 6:356. [PMID: 26779253 PMCID: PMC4703773 DOI: 10.3389/fgene.2015.00356] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 12/10/2015] [Indexed: 01/11/2023] Open
Abstract
Introduction: Efavirenz (EFV) is a non-nucleoside reverse transcriptase inhibitor prescribed as part of first-line highly active antiretroviral therapy (HAART) in South Africa. Despite administration of fixed doses of EFV, inter-individual variability in plasma concentrations has been reported. Poor treatment outcomes such as development of adverse drug reactions or treatment failure have been linked to EFV plasma concentrations outside the therapeutic range (1–4 μg/mL) in some studies. The drug metabolizing enzyme (DME), CYP2B6, is primarily responsible for EFV metabolism with minor contributions by CYP1A2, CYP2A6, CYP3A4, CYP3A5, and UGT2B7. DME coding genes are also regulated by microRNAs through targeting the 3′-untranslated region. Expanded analysis of 30 single nucleotide polymorphisms (SNPs), including those in the 3′-UTR, was performed to identify pharmacogenetics determinants of EFV plasma concentrations in addition to CYP2B6 c.516G>T and c.983T>C SNPs. Methods: SNPs in CYP1A2, CYP2B6, UGT2B7, and NR1I2 (PXR) were selected for genotyping among 222 Bantu-speaking South African HIV-infected patients receiving EFV-containing HAART. This study is a continuation of earlier pharmacogenetics studies emphasizing the role of genetic variation in the 3′-UTR of genes which products are either pharmacokinetic or pharmacodynamic targets of EFV. Results: Despite evaluating thirty SNPs, CYP2B6 c.516G>T and c.983T>C SNPs remain the most prominent predictors of EFV plasma concentration. Conclusion: We have shown that CYP2B6 c.516G>T and c.983T>C SNPs are the most important predictors of EFV plasma concentration after taking into account all other SNPs, including genetic variation in the 3′-UTR, and variables affecting EFV metabolism.
Collapse
|
45
|
Kuter D, Mohunlal R, Fitzroy SM, Asher C, Smith PJ, Egan TJ, de Villiers KA. Insights into the initial stages of lipid-mediated haemozoin nucleation. CrystEngComm 2016. [DOI: 10.1039/c6ce00866f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lipid-mediated haemozoin nucleation, as probed by molecular dynamics, proceeds via aggregation of ferrihaem π–π dimers at a lipid–aqueous interface.
Collapse
|
46
|
Ekengard E, Kumar K, Fogeron T, de Kock C, Smith PJ, Haukka M, Monari M, Nordlander E. Pentamethylcyclopentadienyl-rhodium and iridium complexes containing (N^N and N^O) bound chloroquine analogue ligands: synthesis, characterization and antimalarial properties. Dalton Trans 2016; 45:3905-17. [DOI: 10.1039/c5dt03739e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rhodium and iridium cyclopentadienyl complexes have been examined for anti-malarial activity. Three rhodium complexes are especially active.
Collapse
|
47
|
Adams M, Barnard L, de Kock C, Smith PJ, Wiesner L, Chibale K, Smith GS. Cyclopalladated organosilane–tethered thiosemicarbazones: novel strategies for improving antiplasmodial activity. Dalton Trans 2016; 45:5514-20. [DOI: 10.1039/c5dt04918k] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ferrocenyl- and aryl-derived cyclopalladated organosilane thiosemicarbazone complexes were synthesised via C–H bond activation and evaluated for antiplasmodial activity.
Collapse
|
48
|
Adams M, Stringer T, de Kock C, Smith PJ, Land KM, Liu N, Tam C, Cheng LW, Njoroge M, Chibale K, Smith GS. Bioisosteric ferrocenyl-containing quinolines with antiplasmodial and antitrichomonal properties. Dalton Trans 2016; 45:19086-19095. [DOI: 10.1039/c6dt03175g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bioisosteric (C, Si) ferrocenyl-containing quinolines and ferrocenylamines were prepared and evaluated as antiplasmodial and antitrichomonal agents.
Collapse
|
49
|
Stringer T, De Kock C, Guzgay H, Okombo J, Liu J, Kanetake S, Kim J, Tam C, Cheng LW, Smith PJ, Hendricks DT, Land KM, Egan TJ, Smith GS. Mono- and multimeric ferrocene congeners of quinoline-based polyamines as potential antiparasitics. Dalton Trans 2016; 45:13415-26. [DOI: 10.1039/c6dt02685k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of mono- and multimeric polyamine-containing ferrocenyl complexes bearing a quinoline motif were prepared.
Collapse
|
50
|
van Schalkwyk DA, Nash MN, Shafik SH, Summers RL, Lehane AM, Smith PJ, Martin RE. Verapamil-Sensitive Transport of Quinacrine and Methylene Blue via the Plasmodium falciparum Chloroquine Resistance Transporter Reduces the Parasite's Susceptibility to these Tricyclic Drugs. J Infect Dis 2015; 213:800-10. [PMID: 26503982 DOI: 10.1093/infdis/jiv509] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/15/2015] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND It is becoming increasingly apparent that certain mutations in the Plasmodium falciparum chloroquine resistance transporter (PfCRT) alter the parasite's susceptibility to diverse compounds. Here we investigated the interaction of PfCRT with 3 tricyclic compounds that have been used to treat malaria (quinacrine [QC] and methylene blue [MB]) or to study P. falciparum (acridine orange [AO]). METHODS We measured the antiplasmodial activities of QC, MB, and AO against chloroquine-resistant and chloroquine-sensitive P. falciparum and determined whether QC and AO affect the accumulation and activity of chloroquine in these parasites. We also assessed the ability of mutant (PfCRT(Dd2)) and wild-type (PfCRT(D10)) variants of the protein to transport QC, MB, and AO when expressed at the surface of Xenopus laevis oocytes. RESULTS Chloroquine resistance-conferring isoforms of PfCRT reduced the susceptibility of the parasite to QC, MB, and AO. In chloroquine-resistant (but not chloroquine-sensitive) parasites, AO and QC increased the parasite's accumulation of, and susceptibility to, chloroquine. All 3 compounds were shown to bind to PfCRT(Dd2), and the transport of QC and MB via this protein was saturable and inhibited by the chloroquine resistance-reverser verapamil. CONCLUSIONS Our findings reveal that the PfCRT(Dd2)-mediated transport of tricyclic antimalarials reduces the parasite's susceptibility to these drugs.
Collapse
|