scholarly journals Characterization of pfmdr1, pfcrt, pfK13, pfubp1, and pfap2mu in travelers returning from Africa with Plasmodium falciparum infections reported in China from 2014–2018

Author(s):  
Jun Feng ◽  
Dongmei Xu ◽  
Xiangli Kong ◽  
Kangming Lin ◽  
He Yan ◽  
...  

The artemisinin-based combination therapies (ACTs) used to treat Plasmodium falciparum in Africa are threatened by the emergence of parasites in Asia carrying variants of the Kelch 13 (K13) locus with delayed clearance in response to ACTs. Single nucleotide polymorphisms (SNPs) in other molecular markers, such as ap2mu and ubp1, were associated with artemisinin resistance in rodent malaria and clinical failure in African malaria patients. Here, we characterized the polymorphisms in pfmdr1, pfcrt, pfK13, pfubp1 and pfap2mu among African isolates reported in Shandong and Guangxi provinces in China. Among 144 patients with P. falciparum returning from Africa in 2014–2018, pfmdr1 N86Y (8.3%) and pfcrt K76T (2.1%) were the major mutant alleles. The most common genotype for pfcrt was I74E75T76 (8.3%), followed by E75T76 (2.1%). For K13 polymorphisms, a limited number of mutated alleles were observed, and A578S was the most frequently detected allele in 3 isolates (2.1%). A total of 27.1% (20/144) of the isolates were found to contain pfubp1 mutations, including 6 nonsynonymous and 2 synonymous mutations. The pfubp1 genotypes associated with ART resistance were D1525E (10.4%) and E1528D (8.3%). Furthermore, 11 SNPs were identified in pfap2mu, and S160N was the major polymorphism (4.2%). Additionally, 4 different types of insertions were found in pfap2mu, and the codon AAT, encoding aspartic acid, was more frequently observed at codons 226 (18.8%) and 326 (10.7%). Moreover, 4 different types of insertions were observed in pfubp1 at codon 1520, which was the most common (6.3%). These findings indicate a certain degree of variation in other potential molecular markers, such as pfubp1 and pfap2mu, and their roles either in the parasite’s mechanism of resistance or the mode of action should be evaluated or elucidated further.

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Najia Karim Ghanchi ◽  
Bushra Qurashi ◽  
Hadiqa Raees ◽  
Mohammad Asim Beg

Abstract Background K13 propeller (k13) polymorphism are useful molecular markers for tracking the emergence and spread of artemisinin resistance in Plasmodium falciparum. Polymorphisms are reported from Cambodia with rapid invasion of the population and almost near fixation in south East Asia. The study describes single nucleotide polymorphisms in Kelch protein propeller domain of P. falciparum associated with artemisinin resistance from Southern Pakistan. Methods Two hundred and forty-nine samples were collected from patients with microscopy confirmed P. falciparum malaria attending Aga Khan University Hospital during September 2015-April 2018. DNA was isolated using the whole blood protocol for the QIAmp DNA Blood Kit. The k13 propeller gene (k13) was amplified using nested PCR. Double-strand sequencing of PCR products was performed using Sanger sequencing methodology. Sequences were analysed with MEGA 6 and Bio edit software to identify specific SNP combinations. Results All isolates analysed for k13 propeller allele were observed as wild-type in samples collected post implementation of ACT in Pakistan. C580Y, A675V, Y493H and R539T variants associated with reduced susceptibility to artemisinin-based combination therapy (ACT) were not found. Low frequency of M476I and C469Y polymorphisms was found, which is significantly associated with artemisinin resistance. Conclusion Low frequencies of both nonsynonymous and synonymous polymorphisms were observed in P. falciparum isolates circulating in Southern Pakistan. The absence of known molecular markers of artemisinin resistance in this region is favourable for anti-malarial efficacy of ACT. Surveillance of anti-malarial drug resistance to detect its emergence and spread need to be strengthened in Pakistan.


2019 ◽  
Vol 63 (10) ◽  
Author(s):  
Ruimin Zhou ◽  
Chengyun Yang ◽  
Suhua Li ◽  
Yuling Zhao ◽  
Ying Liu ◽  
...  

ABSTRACT Angola was the main origin country for the imported malaria in Henan Province, China. Antimalarial drug resistance has posed a threat to the control and elimination of malaria. Several molecular markers were confirmed to be associated with the antimalarial drug resistance, such as pfcrt, pfmdr1, pfdhfr, pfdhps, and K13. This study evaluated the drug resistance of the 180 imported Plasmodium falciparum isolates from Angola via nested PCR using Sanger sequencing. The prevalences of pfcrt C72V73M74N75K76, pfmdr1 N86Y184S1034N1042D1246, pfdhfr A16N51C59S108D139I164, and pfdhps S436A437A476K540A581 were 69.4%, 59.9%, 1.3% and 6.3%, respectively. Three nonsynonymous (A578S, M579I, and Q613E) and one synonymous (R471R) mutation of K13 were found, the prevalences of which were 2.5% and 1.3%, respectively. The single nucleotide polymorphisms (SNPs) in pfcrt, pfmdr1, pfdhfr, and pfdhps were generally shown as multiple mutations. The mutant prevalence of pfcrt reduced gradually, but pfdhfr and pfdhps still showed high mutant prevalence, while pfmdr1 was relatively low. The mutation of the K13 gene was rare. Molecular surveillance of artemisinin (ART) resistance will be used as a tool to evaluate the real-time efficacy of the artemisinin-based combination therapies (ACTs) and the ART resistance situation.


2010 ◽  
Vol 55 (1) ◽  
pp. 94-100 ◽  
Author(s):  
Kazuyuki Tanabe ◽  
Sedigheh Zakeri ◽  
Nirianne Marie Q. Palacpac ◽  
Manada Afsharpad ◽  
Milijaona Randrianarivelojosia ◽  
...  

ABSTRACTRecent reports on the decline of the efficacy of artemisinin-based combination therapies (ACTs) indicate a serious threat to malaria control. The endoplasmic/sarcoplasmic reticulum Ca2+-ATPase ortholog ofPlasmodium falciparum(PfSERCA) has been suggested to be the target of artemisinin and its derivatives. It is assumed that continuous artemisinin pressure will affect polymorphism of the PfSERCA gene (serca) if the protein is the target. Here, we investigated the polymorphism ofsercain parasite populations unexposed to ACTs to obtain baseline information for the study of potential artemisinin-driven selection of resistant parasites. Analysis of 656 full-length sequences from 13 parasite populations in Africa, Asia, Oceania, and South America revealed 64 single nucleotide polymorphisms (SNPs), of which 43 were newly identified and 38 resulted in amino acid substitutions. No isolates showed L263E and S769N substitutions, which were reportedly associated with artemisinin resistance. Among the four continents, the number of SNPs was highest in Africa. In Africa, Asia, and Oceania, common SNPs, or those with a minor allele frequency of ≥0.05, were less prevalent, with most SNPs noted to be continent specific, whereas in South America, common SNPs were highly prevalent and often shared with those in Africa. Of 50 amino acid haplotypes observed, only one haplotype (3D7 sequence) was seen in all four continents (64%). Forty-eight haplotypes had frequencies of less than 5%, and 40 haplotypes were continent specific. The geographical difference in the diversity and distribution ofsercaSNPs and haplotypes lays the groundwork for assessing whether some artemisinin resistance-associated mutations and haplotypes are selected by ACTs.


2019 ◽  
Vol 63 (7) ◽  
Author(s):  
Karryn Gresty ◽  
Karen Anderson ◽  
Cielo Pasay ◽  
Norman C. Waters ◽  
Qin Cheng

ABSTRACT The South Pacific countries Solomon Islands, Vanuatu, and Papua New Guinea (PNG) adopted artemisinin-based combination therapies (ACTs) in 2008. We examined Kelch 13 and Kelch 12 genes in parasites originating from these countries before or at ACT introduction. Four Kelch 13 and two Kelch 12 novel sequence polymorphisms, not associated with artemisinin resistance, were observed in parasites from Solomon Islands and Vanuatu. No polymorphisms were observed in PNG parasites. The findings provide useful baseline information.


Author(s):  
Tine Kliim Nydahl ◽  
Samuel Yao Ahorhorlu ◽  
Magatte Ndiaye ◽  
Manoj Kumar Das ◽  
Helle Hansson ◽  
...  

The emergence of artemisinin-resistant Plasmodium falciparum parasites in Southeast Asia threatens malaria control and elimination. The interconnectedness of parasite populations may be essential to monitor the spread of resistance. Combining a published barcoding system of geographically restricted single-nucleotide polymorphisms (SNPs), mainly mitochondria of P. falciparum with SNPs in the K13 artemisinin resistance marker, could elucidate the parasite population structure and provide insight regarding the spread of drug resistance. We explored the diversity of mitochondrial SNPs (bp position 611-2825) and identified K13 SNPs from malaria patients in the districts of India (Ranchi), Tanzania (Korogwe), and Senegal (Podor, Richard Toll, Kaolack, and Ndoffane). DNA was amplified using a nested PCR and Sanger-sequenced. Overall, 199 K13 sequences (India: N = 92; Tanzania: N = 48; Senegal: N = 59) and 237 mitochondrial sequences (India: N = 93; Tanzania: N = 48; Senegal: N = 96) were generated. SNPs were identified by comparisons with reference genomes. We detected previously reported geographically restricted mitochondrial SNPs (T2175C and G1367A) as markers for parasites originating from the Indian subcontinent and several geographically unrestricted mitochondrial SNPs. Combining haplotypes with published P. falciparum mitochondrial genome data suggested possible regional differences within India. All three countries had G1692A, but Tanzanian and Senegalese SNPs were well-differentiated. Some mitochondrial SNPs are reported here for the first time. Four nonsynonymous K13 SNPs were detected: K189T (India, Tanzania, Senegal); A175T (Tanzania); and A174V and R255K (Senegal). This study supports the use of mitochondrial SNPs to determine the origin of the parasite and suggests that the P. falciparum populations studied were susceptible to artemisinin during sampling because all K13 SNPs observed were outside the propeller domain for artemisinin resistance.


2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Fang Huang ◽  
Biraj Shrestha ◽  
Hui Liu ◽  
Lin-Hua Tang ◽  
Shui-Sen Zhou ◽  
...  

Abstract Background The emergence and spread of artemisinin resistance in Plasmodium falciparum poses a threat to malaria eradication, including China’s plan to eliminate malaria by 2020. Piperaquine (PPQ) resistance has emerged in Cambodia, compromising an important partner drug that is widely used in China in the form of dihydroartemisinin (DHA)-PPQ. Several mutations in a P. falciparum gene encoding a kelch protein on chromosome 13 (k13) are associated with artemisinin resistance and have arisen spread in the Great Mekong subregion, including the China–Myanmar border. Multiple copies of the plasmepsin II/III (pm2/3) genes, located on chromosome 14, have been shown to be associated with PPQ resistance. Methods The therapeutic efficacy of DHA-PPQ for the treatment of uncomplicated P. falciparum was evaluated along the China–Myanmar border from 2010 to 2014. The dry blood spots samples collected in the efficacy study prior DHA-PPQ treatment and from the local hospital by passive detection were used to amplify k13 and pm2. Polymorphisms within k13 were genotyped by capillary sequencing and pm2 copy number was quantified by relative-quantitative real-time polymerase chain reaction. Treatment outcome was evaluated with the World Health Organization protocol. A linear regression model was used to estimate the association between the day 3 positive rate and k13 mutation and the relationship of the pm2 copy number variants and k13 mutations. Results DHA-PPQ was effective for uncomplicated P. falciparum infection in Yunnan Province with cure rates > 95%. Twelve non synonymous mutations in the k13 domain were observed among the 268 samples with the prevalence of 44.0% and the predominant mutation was F446I with a prevalence of 32.8%. Only one sample was observed with multi-copies of pm2, including parasites with and without k13 mutations. The therapeutic efficacy of DHA-PPQ was > 95% along the China–Myanmar border, consistent with the lack of amplification of pm2. Conclusion DHA-PPQ for uncomplicated P. falciparum infection still showed efficacy in an area with artemisinin-resistant malaria along the China–Myanmar border. There was no evidence to show PPQ resistance by clinical study and molecular markers survey. Continued monitoring of the parasite population using molecular markers will be important to track emergence and spread of resistance in this region.


2021 ◽  
Author(s):  
Weijia Cheng ◽  
Kai Wu ◽  
Xiaonan Song ◽  
Wang Wei ◽  
Weixing Du ◽  
...  

Abstract BackgroundMolecular markers for monitoring resistance could help improve malaria treatment policies. Delayed clearance of Plasmodium falciparum by Artemisinin-based Combination Therapies (ACTs) has been reported in several countries. In addition to the PfKelch13 (pfk13), new drug resistance genes, the ubiquitin-specific protease 1 (pfubp1) and the eadaptor protein complex 2 mu subunit (pfap2mu) have been identified as being linked to ACTs. This study investigated the prevalence of single-nucleotide polymorphisms (SNPs) in clinical P. falciparum isolates pfubp1 and pfap2mu imported from Africa and Southeast Asia (SEA) to Wuhan, China, to provide baseline data for antimalarial resistance monitoring in this region.MethodsPeripheral Blood samples were collected in Wuhan, China, from August 2011 to December 2019. The SNPs of Pfubp1 and pfap2mu of P. falciparum were determined by nested PCR and Sanger sequencing. ResultsIn total, 296 samples were collected. Subsequently, 92.23% (273/296) were successfully amplified and sequenced for the Pfubp1. There were 60.07% (164/273) wild strains and 39.93% (109/273) mutant strains. For the pfap2mu gene, it was divided into three fragments for amplification, 82.77% (245/296), 90.20% (267/296) and 94.59% (280/296) were sequenced successfully respectively. Genotypes reportedly associated with ACTs resistance detected in this study included pfubp1 D1525E as well as E1528D and pfap2mu S160N. The mutation prevalence rates were 10.99% (30/273), 13.19% (36/273) and 11.24% (30/267), respectively. These are all focused on Congo, Nigeria and Angola. And known delayed-clearance parasite mutation has also been found in SEA.ConclusionsThe existence of mutation sites of known clearance genes detected in the isolates in this study, including D1525E and E1528D in the pfubp1 gene, and S160N in the pfap2mu gene, further proved the risk of ACTs resistance. Constant vigilance is therefore needed to protect the effectiveness of ACTs, and to prevent the spread of drug-resistant P. falciparum. Further studies in malaria-endemic countries are needed to further validate potential genetic markers for monitoring parasite populations in Africa and SEA.


2018 ◽  
Vol 5 (9) ◽  
pp. 2651-2657
Author(s):  
Titilope M. Dokunmu ◽  
Grace I. Olasehinde ◽  
David O. Oladejo ◽  
Cynthia U. Adjekukor ◽  
Adesola E. Akinbohun ◽  
...  

Introduction: Plasmodium falciparum has developed resistance to artemisinin drugs in Southeast Asia, and its reduced sensitivity has been reported in other regions. This study aims to determine parasite susceptibility to the bioactive form of artemisinin derivatives- dihydroartemisinin (DHA)-, and to detect the K13 polymorphism in isolates from an endemic area of Nigeria. Methods: Ex-vivo response in 55 parasites isolates obtained from malaria-positive patients were exposed to pulse DHA concentration and cultured for 66 hours ex-vivo. Parasite ring stage survival (RSAex-vivo) relative to unexposed matched control was determined by microscopy, and parasite growth was compared using Mann-Whitney U-test at a significance level of P<0.05. The Kelch propeller gene was amplified using specific primers, then sequenced and analyzed for single nucleotide polymorphisms (SNPs), which were compared to reference PF3D7_1343700. Results: Overall, 151 of 375 (40.2%) individuals were positive during the study period. In 55 selected isolates, there was increased growth in unexposed wells but growth was inhibited in DHA-exposed wells, with growth rate between 14.9 – 96.7%. The mean RSAex-vivo value was 0.18 ± 0.09%, 95% CI (0.15-0.20). There was no significant mutation of the K13 gene in the parasite isolates evaluated. Conclusions: Plasmodium falciparum isolates from this endemic area show high sensitivity to dihydroartemisinin ex-vivo, with no mutations conferring artemisinin resistance. Continuous monitoring of parasite susceptibility to artemisinin combination drugs should be intensified to reduce chances of artemisinin resistance in endemic areas.


2021 ◽  
Author(s):  
Weijia Cheng ◽  
Kai Wu ◽  
Xiaonan Song ◽  
Wang Wei ◽  
Weixing Du ◽  
...  

Abstract BackgroundMolecular markers for monitoring resistance could help improve malaria treatment policies. Delayed clearance of Plasmodium falciparum by Artemisinin-based Combination Therapies (ACTs) has been reported in several countries. In addition to the PfKelch13 (pfk13), new drug resistance genes, the ubiquitin-specific protease 1 (pfubp1) and the eadaptor protein complex 2 mu subunit (pfap2mu) have been identified as being linked to ACTs. This study investigated the prevalence of single-nucleotide polymorphisms (SNPs) in clinical Plasmodium falciparum isolates pfubp1 and pfap2mu imported from Africa and Southeast Asia (SEA) to Wuhan, China, to provide baseline data for antimalarial resistance monitoring in this region.MethodsPeripheral Blood samples were collected in Wuhan, China, from August 2011 to December 2019. The SNPs of Pfubp1 and pfap2mu of P. falciparum were determined by nested PCR and Sanger sequencing. ResultsIn total, 296 samples were collected. Subsequently, 92.23% (273/296) were successfully amplified and sequenced for the Pfubp1. There were 60.07% (164/273) wild strains and 39.93% (109/273) mutant strains. For the pfap2mu gene, it was divided into three fragments for amplification, 82.77% (245/296), 90.20% (267/296) and 94.59% (280/296) were sequenced successfully respectively. Genotypes reportedly associated with ACTs resistance detected in this study included pfubp1 D1525E as well as E1528D and pfap2mu S160N. The mutation prevalence rates were 10.99% (30/273), 13.19% (36/273) and 11.24% (30/267), respectively. ConclusionsThe existence of mutation sites of known clearance genes detected in the isolates in this study, including D1525E and E1528D in the pfubp1 gene, and S160N in the pfap2mu gene, further proved the risk of ACTs resistance. Constant vigilance is therefore needed to protect the effectiveness of ACTs, and to prevent the spread of drug-resistant P. falciparum. Further studies in malaria-endemic countries are needed to further validate potential genetic markers for monitoring parasite populations in Africa and SEA.


Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1386
Author(s):  
Soyun Kim ◽  
Keunho Yun ◽  
Han Yong Park ◽  
Ju Young Ahn ◽  
Ju Yeon Yang ◽  
...  

Red radish (Raphanus sativus L.) cultivars are a rich source of health-promoting anthocyanins and are considered a potential source of natural colorants used in the cosmetic industry. However, the development of red radish cultivars via conventional breeding is very difficult, given the unusual inheritance of the anthocyanin accumulation trait in radishes. Therefore, molecular markers linked with radish color are needed to facilitate radish breeding. Here, we characterized the RsTT8 gene isolated from four radish genotypes with different skin and flesh colors. Sequence analysis of RsTT8 revealed a large number of polymorphisms, including insertion/deletions (InDels), single nucleotide polymorphisms (SNPs), and simple sequence repeats (SSRs), between the red-fleshed and white-fleshed radish cultivars. To develop molecular markers on the basis of these polymorphisms for discriminating between radish genotypes with different colored flesh tissues, we designed four primer sets specific to the RsTT8 promoter, InDel, SSR, and WD40/acidic domain (WD/AD), and tested these primers on a diverse collection of radish lines. Except for the SSR-specific primer set, all primer sets successfully discriminated between red-fleshed and white-fleshed radish lines. Thus, we developed three molecular markers that can be efficiently used for breeding red-fleshed radish cultivars.


Sign in / Sign up

Export Citation Format

Share Document