Homology modeling of wild type and pyrimethamine/cycloguanil-cross resistant mutant type Plasmodium falciparum dihydrofolate reductase. A model for antimalarial chemotherapy resistance

2001 ◽  
Vol 91 (3) ◽  
pp. 305-317 ◽  
Author(s):  
Osvaldo Andrade Santos-Filho ◽  
Ricardo Bicca de Alencastro ◽  
Jose Daniel Figueroa-Villar
Keyword(s):  
Plasmodium Falciparum ◽  
Homology Modeling ◽  
Dihydrofolate Reductase ◽  
Chemotherapy Resistance ◽  
Resistant Mutant ◽  
Wild Type ◽  
Mutant Type ◽  
Antimalarial Chemotherapy

scholarly journals Kenyan Plasmodium falciparum Field Isolates: Correlation between Pyrimethamine and Chlorcycloguanil Activity In Vitro and Point Mutations in the Dihydrofolate Reductase Domain

1998 ◽  
Vol 42 (1) ◽  
pp. 164-169 ◽  
Author(s):  
A. Nzila-Mounda ◽  
E. K. Mberu ◽  
C. H. Sibley ◽  
C. V. Plowe ◽  
P. A. Winstanley ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Dihydrofolate Reductase ◽  
Drug Response ◽  
Point Mutations ◽  
Distinct Group ◽  
Wild Type ◽  
Field Isolates ◽  
Vitro Data ◽  
In Vitro Data

ABSTRACT Sixty-nine Kenyan Plasmodium falciparum field isolates were tested in vitro against pyrimethamine (PM), chlorcycloguanil (CCG), sulfadoxine (SD), and dapsone (DDS), and their dihydrofolate reductase (DHFR) genotypes were determined. The in vitro data show that CCG is more potent than PM and that DDS is more potent than SD. DHFR genotype is correlated with PM and CCG drug response. Isolates can be classified into three distinct groups based on their 50% inhibitory concentrations (IC50s) for PM and CCG (P< 0.01) and their DHFR genotypes. The first group consists of wild-type isolates with mean PM and CCG IC50s of 3.71 ± 6.94 and 0.24 ± 0.21 nM, respectively. The second group includes parasites which all have mutations at codon 108 alone or also at codons 51 or 59 and represents one homogeneous group for which 25- and 6-fold increases in PM and CCG IC50s, respectively, are observed. Parasites with mutations at codons 108, 51, and 59 (triple mutants) form a third distinct group for which nine- and eightfold increases in IC50s, respectively, of PM and CCG compared to the second group are observed. Surprisingly, there is a significant decrease (P < 0.01) of SD and DDS susceptibility in these triple mutants. Our data show that more than 92% of Kenyan field isolates have undergone at least one point mutation associated with a decrease in PM activity. These findings are of great concern because they may indicate imminent PM-SD failure, and there is no affordable antimalarial drug to replace PM-SD (Fansidar).

Molecular modeling of wild-type and antifolate resistant mutant Plasmodium falciparum DHFR

2002 ◽  
Vol 98 (3) ◽  
pp. 287-300 ◽  
Author(s):  
Reinaldo Teixeira Delfino ◽  
Osvaldo Andrade Santos-Filho ◽  
José Daniel Figueroa-Villar
Keyword(s):  
Plasmodium Falciparum ◽  
Molecular Modeling ◽  
Resistant Mutant ◽  
Wild Type

scholarly journals Molecular Surveillance of Antimalarial Resistance Pfcrt, Pfmdr1 and Pfk13 Polymorphisms in African Plasmodium Falciparum Imported Parasites to Wuhan, China

2020 ◽  
Author(s):  
Cheng Weijia ◽  
Xiaonan Song ◽  
Huabing Tan ◽  
Kai Wu ◽  
Jian Li
Keyword(s):  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Mixed Type ◽  
Antimalarial Drugs ◽  
Wild Type ◽  
Mutant Type ◽  
Molecular Surveillance ◽  
Severe Problem ◽  
Antimalarial Resistance ◽  
Effective Drugs

Abstract Background: The development of drug resistance in Plasmodium falciparum becomes a severe problem for malaria control globally. Before finding a practical solution, monitoring the susceptibility of P. falciparum resistance-related genes is crucial. It will offer valuable information on the drug resistance in malaria-endemic areas and guides the rational clinical use of antimalarial drugs.Methods：Filter paper blood was taken from patients with positive P. falciparum during 2017-2019 in Wuhan, China. The target fragments from pfcrt, pfmdr1, and k13 propeller (pfk13) genes of P. falciparum were amplified and sequenced. Subsequently, the polymorphisms of pfcrt, pfmdr1, and pfk13 and the haplotypes of Pfcrt and Pfmdr1 were analyzed.Results: Totally, 106 samples were collected. Subsequently, 98.11% (104/106), 100% (106/106), and 86.79% (92/106) of these samples were successfully amplified and sequenced for the pfcrt, pfmdr1, and pfk13 genes, respectively. The prevalence of Pfcrt K76T, Pfmdr1 N86Y, and Pfmdr1 Y184F mutation were 9.62%, 4.72%, and 47.17%, respectively. At codons 72-76 of pfcrt gene locus were showed three haplotypes, including CVMNK (wild-type), CVIET (mutation type), CV M/I N/E K/T (mixed type), with 87.50%, 9.62%, and 2.88% prevalence, respectively. For the pfmdr1 gene, including NY (wild type), NF and YF (mutant type), N Y/F, Y Y/F, and N/Y Y/F (mixed type), accounted for 34.91%, 43.40%, 3.77%, 15.09%, 0.94%, and 1.89%, respectively. A total of eleven Pfcrt/Pfmdr1 combined haplotypes, including six types of combined haplotypes, and five combined haplotypes with mixed-type, For pfk13, no mutation was detected. Conclusions: The wild-type SNPs and haplotypes for the pfcrt, and pfmdr1 genes become predominant in the current study. It indicates these isolates entirely or partly recovery their susceptibility to antimalarial drugs, including chloroquine, amodiaquine, and mefloquine. Moreover, it demonstrates these drugs can continue to be effective drugs for P. falciparum malaria cases treatment in Africa. Although no mutation is detected in pfk13, continuous molecular surveillance is still urgently necessary.

scholarly journals Molecular Characterization and Diagnosis of QoI Resistance in Cucumber and Eggplant Fungal Pathogens

2007 ◽  
Vol 97 (11) ◽  
pp. 1458-1466 ◽  
Author(s):  
H. Ishii ◽  
K. Yano ◽  
H. Date ◽  
A. Furuta ◽  
Y. Sagehashi ◽  
...  
Keyword(s):  
Cytochrome B ◽  
Fungal Pathogens ◽  
Protective Efficacy ◽  
Resistant Mutant ◽  
Amino Acid Position ◽  
Cytochrome B Gene ◽  
Detection Sensitivity ◽  
Wild Type ◽  
Mutant Type ◽  
Qoi Resistance

The molecular mechanism of QoI fungicide resistance was studied using isolates of cucumber Corynespora leaf spot fungus (Corynespora cassiicola) and the eggplant leaf mold (Mycovellosiella nattrassii). In both pathogens, a mutation at position 143 from glycine to alanine (G143A) was detected in the cytochrome b gene that encodes for the fungicide-targeted protein. Moreover, the nucleotide sequence at amino acid position 143 was converted from GGT or GGA in sensitive (wild-type) to GCT or GCA in resistant (mutant-type) isolates. The methods of polymerase chain reaction restriction fragment length polymorphism commonly used for QoI resistance monitoring were employed successfully, leading to the amplified gene fragment from resistant isolates being cut with the restriction enzyme ItaI. However, heteroplasmy (the coexistence of wild-type and mutated alleles) was found when the resistant isolates of C. cassiicola, M. nattrassii, and Colletotrichum gloeosporioides (strawberry anthracnose fungus) were subcultured in the presence or absence of QoI fungicides. QoI resistance of cucumber powdery and downy mildew isolates persisted for a few years following the removal of the selection pressure imposed by the fungicide under both laboratory and commercial greenhouse conditions. The proportion of mutated sequences in cytochrome b gene decreased over time in the pathogen population. The protective efficacy of the full dose of azoxystrobin decreased when the populations of powdery and downy mildews contained resistant isolates at 10%. Using FMBIO, a fluorescence bio-imaging analyzer, the mutant allele from the QoI-resistant isolates could be detected at the level of 1%, whereas the detection sensitivity of ethidium-bromide-stained gels was ≈10 times lower.

scholarly journals Prevalence of Mutations Associated with Higher Levels of Sulfadoxine-Pyrimethamine Resistance in Plasmodium falciparum Isolates from Car Nicobar Island and Assam, India

2006 ◽  
Vol 50 (11) ◽  
pp. 3934-3938 ◽  
Author(s):  
Anwar Ahmed ◽  
Vanshika Lumb ◽  
Manoj K. Das ◽  
Vas Dev ◽  
Wajihullah ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Dihydrofolate Reductase ◽  
Drug Policy ◽  
Uttar Pradesh ◽  
Nicobar Island ◽  
Wild Type

ABSTRACT To assess sulfadoxine and pyrimethamine resistance (SPR), we describe here the dihydropteroate synthetase (DHPS) mutations among the Plasmodium falciparum isolates in which dihydrofolate reductase (DHFR) mutations had recently been described by us (A. Ahmed, M. K. Das, V. Dev, M. A. Saifi, Wajihullah, and Y. D. Sharma, Antimicrob. Agents Chemother. 50:1546-1549, 2006). A majority of isolates from Car Nicobar island showed double DHPS mutations, whereas a majority of isolates from Uttar Pradesh (U.P.) and Assam contained the wild-type DHPS. Based on DHFR-DHPS mutations, the expected level of SPR was lowest in U.P., higher in Assam, and highest in Car Nicobar, suggesting that a region-wise drug policy is needed in India.

Discovery of traditional Chinese medicine derived compounds as wild type and mutant Plasmodium falciparum dihydrofolate reductase inhibitors: Induced fit docking and ADME studies

2020 ◽  
Vol 17 ◽  
Author(s):  
Opeyemi Iwaloye ◽  
Olusola Olalekan Elekofehinti ◽  
Babatomiwa Kikiowo ◽  
Toyin Mary Fadipe ◽  
Moses Orimoloye Akinjiyan ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Dihydrofolate Reductase ◽  
Active Sites ◽  
Wild Type ◽  
Induced Fit Docking ◽  
Induced Fit ◽  
Lipinski’S Rule ◽  
Drug Candidates

Background: In a bid to come up with effective compounds as inhibitors in antimalarial treatment, we built a library containing about 2,000 traditional Chinese medicine(TCM)-derived compounds retrieved from TCM Data-base@Taiwan. The active sites of both the wild type and mutant Plasmodium falciparum dihydrofolate reductase (pfDHFR) were explored using computational tools. pfDHFR, one of the prime drug targets in the prevention of malaria infection induced by the female anopheles mosquito has continued to coffer resistance to drugs (antifolates) due to mutation in some of the key amino acid residues crucial for its inhibition. Results: We utilized virtual throughput screening and glide XP docking to screen the compounds, and 8 compounds were found to have promising docking score with both the wild type and mutant pfDHFR. They were further subjected to induced fit docking (IFD) to affirm their inhibitory potency. The ADME properties and biological activity spectrum of the com-pounds were also considered. Inspection of the inhibition profile of the compounds demonstrated that a number of the com-pounds form intermolecular interaction with ASP54, ILE14, LEU164, SER108/ASN108, ARG122 and ASP58. Majority of the compounds are considered to be drug candidates due to their antiprotozoal activities and accordance with Lipinski’s rule of five (ROF). Conclusion: The outcome of the present study should further be investigated to attest the efficacy of these compounds as better drug candidates than the antifolates.

scholarly journals Conflicting Requirements of Plasmodium falciparum Dihydrofolate Reductase Mutations Conferring Resistance to Pyrimethamine-WR99210 Combination

2007 ◽  
Vol 51 (12) ◽  
pp. 4356-4360 ◽  
Author(s):  
Deanpen Japrung ◽  
Ubolsree Leartsakulpanich ◽  
Sudsanguan Chusacultanachai ◽  
Yongyuth Yuthavong
Keyword(s):  
Plasmodium Falciparum ◽  
Dihydrofolate Reductase ◽  
Enzyme Inhibitor ◽  
Random Mutagenesis ◽  
Wild Type ◽  
Resistance Mutations ◽  
Inhibitor Binding ◽  
Drug Classes ◽  
Antifolate Resistance ◽  
Resistance Mutants

ABSTRACT Plasmodium falciparum strains bearing quadruple mutations of dihydrofolate reductase-thymidylate synthase (PfDHFR-TS) at codons 51, 59, 108, and 164 are highly resistant to pyrimethamine (PYR), a diaminopyrimidine, but sensitive to WR99210 (WR), a cycloguanil analog, suggesting different enzyme-inhibitor binding interactions. A combination of these inhibitors to delay the onset of antifolate resistance is proposed. Using error-prone PCR, libraries of random mutants of wild-type PfDHFR and PfDHFR-TS were generated and used to transform Escherichia coli, and transformants were then selected for PYR or WR resistance. Mutants highly resistant to either PYR or WR were also generated from libraries obtained from further random mutagenesis of quadruple mutants (QM) with mutations in PfDHFR or PfDHFR-TS. For reversion mutants carrying altered residues I51N, N108S, and L164I, a further mutation of D54N was required to achieve resistance against WR, but these mutants regained sensitivity to PYR. When a combination of PYR and WR was used, fewer resistant mutants were generated from both mutant libraries using the QM gene templates. The effectiveness of the drug combination in reducing the appearance of resistance mutations is likely due to conflicting requirements for mutations conferring resistance to the two drugs. Thus, a combination of inhibitors from these two drug classes should be effective in impeding the emergence of P. falciparum resistance to antifolates.

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