scholarly journals Suppression of drug resistance reveals a genetic mechanism of metabolic plasticity in malaria parasites

2017 ◽  
Author(s):  
Ann M. Guggisberg ◽  
Philip M. Frasse ◽  
Andrew J. Jezewski ◽  
Natasha M. Kafai ◽  
Aakash Y. Gandhi ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Malaria Parasite ◽  
Glycolytic Enzyme ◽  
Genetic Mechanism ◽  
Growth Defect ◽  
Loss Of Function ◽  
Malaria Parasites ◽  
Metabolic Plasticity ◽  
Glycolytic Intermediates ◽  
Metabolic Regulators

ABSTRACTIn the malaria parasite Plasmodium falciparum, synthesis of isoprenoids from glycolytic intermediates is essential for survival. The antimalarial fosmidomycin (FSM) inhibits isoprenoid synthesis. In P. falciparum, we identify a loss-of-function mutation in HAD2 (PF3D7_1226300) as necessary for FSM resistance. Enzymatic characterization reveals that HAD2, a member of the haloacid dehalogenase-like hydrolase (HAD) superfamily, is a phosphatase. Harnessing a growth defect in resistant parasites, we select for suppression of HAD2-mediated FSM resistance and uncover hypomorphic suppressor mutations in the locus encoding the glycolytic enzyme phosphofructokinase (PFK9). Metabolic profiling demonstrates that FSM resistance is achieved via increased steady-state levels of MEP pathway and glycolytic intermediates and confirms reduced PFK9 function in the suppressed strains. We identify HAD2 as a novel regulator of malaria parasite metabolism and drug sensitivity and uncover PFK9 as a novel site of genetic metabolic plasticity in the parasite. Our study informs the biological functions of an evolutionarily conserved family of metabolic regulators and reveals a previously undescribed strategy by which malaria parasites adapt to cellular metabolic dysregulation.IMPORTANCEUnique and essential aspects of parasite metabolism are excellent targets for development of new antimalarials. An improved understanding of parasite metabolism and drug resistance mechanisms are urgently needed. The antibiotic fosmidomycin targets the synthesis of essential isoprenoid compounds from glucose and is a candidate for antimalarial development. Our study identifies a novel mechanism of drug resistance and further describes a family of metabolic regulators in the parasite. Using a novel forward genetic approach, we also uncover mutations that suppress drug resistance in the glycolytic enzyme PFK9. Thus, we identify an unexpected genetic mechanism of adaptation to metabolic insult that influences parasite fitness and tolerance to antimalarials.

scholarly journals Suppression of Drug Resistance Reveals a Genetic Mechanism of Metabolic Plasticity in Malaria Parasites

mBio ◽  
2018 ◽  
Vol 9 (6) ◽  
Author(s):  
Ann M. Guggisberg ◽  
Philip M. Frasse ◽  
Andrew J. Jezewski ◽  
Natasha M. Kafai ◽  
Aakash Y. Gandhi ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Malaria Parasite ◽  
Glycolytic Enzyme ◽  
Genetic Mechanism ◽  
Growth Defect ◽  
Malaria Parasites ◽  
Content Type ◽  
Metabolic Plasticity ◽  
Glycolytic Intermediates ◽  
Metabolic Regulators

ABSTRACT In the malaria parasite Plasmodium falciparum, synthesis of isoprenoids from glycolytic intermediates is essential for survival. The antimalarial fosmidomycin (FSM) inhibits isoprenoid synthesis. In P. falciparum, we identified a loss-of-function mutation in HAD2 (P. falciparum 3D7_1226300 [PF3D7_1226300]) as necessary for FSM resistance. Enzymatic characterization revealed that HAD2, a member of the haloacid dehalogenase-like hydrolase (HAD) superfamily, is a phosphatase. Harnessing a growth defect in resistant parasites, we selected for suppression of HAD2-mediated FSM resistance and uncovered hypomorphic suppressor mutations in the locus encoding the glycolytic enzyme phosphofructokinase 9 (PFK9). Metabolic profiling demonstrated that FSM resistance is achieved via increased steady-state levels of methylerythritol phosphate (MEP) pathway and glycolytic intermediates and confirmed reduced PFK9 function in the suppressed strains. We identified HAD2 as a novel regulator of malaria parasite metabolism and drug sensitivity and uncovered PFK9 as a novel site of genetic metabolic plasticity in the parasite. Our report informs the biological functions of an evolutionarily conserved family of metabolic regulators and reveals a previously undescribed strategy by which malaria parasites adapt to cellular metabolic dysregulation. IMPORTANCE Unique and essential aspects of parasite metabolism are excellent targets for development of new antimalarials. An improved understanding of parasite metabolism and drug resistance mechanisms is urgently needed. The antibiotic fosmidomycin targets the synthesis of essential isoprenoid compounds from glucose and is a candidate for antimalarial development. Our report identifies a novel mechanism of drug resistance and further describes a family of metabolic regulators in the parasite. Using a novel forward genetic approach, we also uncovered mutations that suppress drug resistance in the glycolytic enzyme PFK9. Thus, we identify an unexpected genetic mechanism of adaptation to metabolic insult that influences parasite fitness and tolerance of antimalarials.

scholarly journals Adaptive Drug Resistance in Malaria Parasite: A Threat to Malaria Elimination Agenda?

2021 ◽  
Author(s):  
Moses Okpeku
Keyword(s):  
Drug Resistance ◽  
Malaria Elimination ◽  
Malaria Parasite ◽  
Disease Burden ◽  
Drug Application ◽  
African Region ◽  
Malaria Parasites ◽  
Sub Saharan ◽  
Host Development

Malaria is a global disease of importance, especially in the sub-Saharan African region, where malaria accounts for great losses economically and to life. Fight to eliminate this disease has resulted in reduced disease burden in many places where the diseases is endemic. Elimination strategies in most places is focus on the use of treated nets and drug application. Exposure of malaria parasites to anti-malaria drugs have led to the evolution of drug resistance in both parasites and host. Development of drug resistance vary but, studies on adaptive drug resistance has implications and consequences. Our knowledge of this consequences are limited but important for the pursuit of an uninterrupted malaria elimination agenda. This chapter draws our attention to this risks and recommends interventions.

scholarly journals Replication of Plasmodium in reticulocytes can occur without hemozoin formation, resulting in chloroquine resistance

2015 ◽  
Vol 212 (6) ◽  
pp. 893-903 ◽  
Author(s):  
Jing-wen Lin ◽  
Roberta Spaccapelo ◽  
Evelin Schwarzer ◽  
Mohammed Sajid ◽  
Takeshi Annoura ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Drug Development ◽  
Antimalarial Drug ◽  
Malaria Parasite ◽  
Chloroquine Resistance ◽  
Malaria Parasites ◽  
Human Malaria ◽  
Complete Development

Most studies on malaria-parasite digestion of hemoglobin (Hb) have been performed using P. falciparum maintained in mature erythrocytes, in vitro. In this study, we examine Plasmodium Hb degradation in vivo in mice, using the parasite P. berghei, and show that it is possible to create mutant parasites lacking enzymes involved in the initial steps of Hb proteolysis. These mutants only complete development in reticulocytes and mature into both schizonts and gametocytes. Hb degradation is severely impaired and large amounts of undigested Hb remains in the reticulocyte cytoplasm and in vesicles in the parasite. The mutants produce little or no hemozoin (Hz), the detoxification by-product of Hb degradation. Further, they are resistant to chloroquine, an antimalarial drug that interferes with Hz formation, but their sensitivity to artesunate, also thought to be dependent on Hb degradation, is retained. Survival in reticulocytes with reduced or absent Hb digestion may imply a novel mechanism of drug resistance. These findings have implications for drug development against human-malaria parasites, such as P. vivax and P. ovale, which develop inside reticulocytes.

scholarly journals A cornucopia of research resources for the fourth rodent malaria parasite species

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Jane M. Carlton
Keyword(s):  
Malaria Parasite ◽  
Parasite Species ◽  
First Century ◽  
Model Systems ◽  
Rodent Malaria Parasite ◽  
Malaria Parasites ◽  
Rodent Malaria ◽  
Human Malaria ◽  
Plasmodium Vinckei ◽  
Research Resources

AbstractThe study of human malaria caused by species of Plasmodium has undoubtedly been enriched by the use of model systems, such as the rodent malaria parasites originally isolated from African thicket rats. A significant gap in the arsenal of resources of the species that make up the rodent malaria parasites has been the lack of any such tools for the fourth of the species, Plasmodium vinckei. This has recently been rectified by Abhinay Ramaprasad and colleagues, whose pivotal paper published in BMC Biology describes a cornucopia of new P. vinckei ‘omics datasets, mosquito transmission experiments, transfection protocols, and virulence phenotypes, to propel this species firmly into the twenty-first century.

scholarly journals Malaria parasite detection in thick blood smear microscopic images using modified YOLOV3 and YOLOV4 models

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Fetulhak Abdurahman ◽  
Kinde Anlay Fante ◽  
Mohammed Aliy
Keyword(s):  
Object Detection ◽  
Malaria Parasite ◽  
Blood Smear ◽  
Clustering Algorithm ◽  
State Of The Art ◽  
Detection Accuracy ◽  
Small Object ◽  
Thick Blood Smear ◽  
Malaria Parasites ◽  
Microscopic Images

Abstract Background Manual microscopic examination of Leishman/Giemsa stained thin and thick blood smear is still the “gold standard” for malaria diagnosis. One of the drawbacks of this method is that its accuracy, consistency, and diagnosis speed depend on microscopists’ diagnostic and technical skills. It is difficult to get highly skilled microscopists in remote areas of developing countries. To alleviate this problem, in this paper, we propose to investigate state-of-the-art one-stage and two-stage object detection algorithms for automated malaria parasite screening from microscopic image of thick blood slides. Results YOLOV3 and YOLOV4 models, which are state-of-the-art object detectors in accuracy and speed, are not optimized for detecting small objects such as malaria parasites in microscopic images. We modify these models by increasing feature scale and adding more detection layers to enhance their capability of detecting small objects without notably decreasing detection speed. We propose one modified YOLOV4 model, called YOLOV4-MOD and two modified models of YOLOV3, which are called YOLOV3-MOD1 and YOLOV3-MOD2. Besides, new anchor box sizes are generated using K-means clustering algorithm to exploit the potential of these models in small object detection. The performance of the modified YOLOV3 and YOLOV4 models were evaluated on a publicly available malaria dataset. These models have achieved state-of-the-art accuracy by exceeding performance of their original versions, Faster R-CNN, and SSD in terms of mean average precision (mAP), recall, precision, F1 score, and average IOU. YOLOV4-MOD has achieved the best detection accuracy among all the other models with a mAP of 96.32%. YOLOV3-MOD2 and YOLOV3-MOD1 have achieved mAP of 96.14% and 95.46%, respectively. Conclusions The experimental results of this study demonstrate that performance of modified YOLOV3 and YOLOV4 models are highly promising for detecting malaria parasites from images captured by a smartphone camera over the microscope eyepiece. The proposed system is suitable for deployment in low-resource setting areas.

scholarly journals Genome sequence, transcriptome, and annotation of rodent malaria parasite Plasmodium yoelii nigeriensis N67

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Cui Zhang ◽  
Cihan Oguz ◽  
Sue Huse ◽  
Lu Xia ◽  
Jian Wu ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Malaria Parasite ◽  
Vaccine Development ◽  
De Novo ◽  
Gene Families ◽  
Plasmodium Yoelii ◽  
Control Measures ◽  
Effective Control ◽  
Malaria Parasites ◽  
Rodent Malaria

Abstract Background Rodent malaria parasites are important models for studying host-malaria parasite interactions such as host immune response, mechanisms of parasite evasion of host killing, and vaccine development. One of the rodent malaria parasites is Plasmodium yoelii, and multiple P. yoelii strains or subspecies that cause different disease phenotypes have been widely employed in various studies. The genomes and transcriptomes of several P. yoelii strains have been analyzed and annotated, including the lethal strains of P. y. yoelii YM (or 17XL) and non-lethal strains of P. y. yoelii 17XNL/17X. Genomic DNA sequences and cDNA reads from another subspecies P. y. nigeriensis N67 have been reported for studies of genetic polymorphisms and parasite response to drugs, but its genome has not been assembled and annotated. Results We performed genome sequencing of the N67 parasite using the PacBio long-read sequencing technology, de novo assembled its genome and transcriptome, and predicted 5383 genes with high overall annotation quality. Comparison of the annotated genome of the N67 parasite with those of YM and 17X parasites revealed a set of genes with N67-specific orthology, expansion of gene families, particularly the homologs of the Plasmodium chabaudi erythrocyte membrane antigen, large numbers of SNPs and indels, and proteins predicted to interact with host immune responses based on their functional domains. Conclusions The genomes of N67 and 17X parasites are highly diverse, having approximately one polymorphic site per 50 base pairs of DNA. The annotated N67 genome and transcriptome provide searchable databases for fast retrieval of genes and proteins, which will greatly facilitate our efforts in studying the parasite biology and gene function and in developing effective control measures against malaria.

scholarly journals Assessment of the Drug Susceptibility of Plasmodium falciparum Clinical Isolates from Africa by Using a Plasmodium Lactate Dehydrogenase Immunodetection Assay and an Inhibitory Maximum Effect Model for Precise Measurement of the 50-Percent Inhibitory Concentration

2006 ◽  
Vol 50 (10) ◽  
pp. 3343-3349 ◽  
Author(s):  
Halima Kaddouri ◽  
Serge Nakache ◽  
Sandrine Houzé ◽  
France Mentré ◽  
Jacques Le Bras
Keyword(s):  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Lactate Dehydrogenase ◽  
Active Metabolite ◽  
Inhibitory Concentration ◽  
Drug Susceptibility ◽  
Maximum Effect ◽  
Malaria Parasites ◽  
Effect Model

ABSTRACT The extension of drug resistance among malaria-causing Plasmodium falciparum parasites in Africa necessitates implementation of new combined therapeutic strategies. Drug susceptibility phenotyping requires precise measurements. Until recently, schizont maturation and isotopic in vitro assays were the only methods available, but their use was limited by technical constraints. This explains the revived interest in the development of replacement methods, such as the Plasmodium lactate dehydrogenase (pLDH) immunodetection assay. We evaluated a commercially controlled pLDH enzyme-linked immunosorbent assay (ELISA; the ELISA-Malaria antigen test; DiaMed AG, Cressier s/Morat, Switzerland) to assess drug susceptibility in a standard in vitro assay using fairly basic laboratory equipment to study the in vitro resistance of malaria parasites to major antimalarials. Five Plasmodium falciparum clones and 121 clinical African isolates collected during 2003 and 2004 were studied by the pLDH ELISA and the [8-3H]hypoxanthine isotopic assay as a reference with four antimalarials. Nonlinear regression with a maximum effect model was used to estimate the 50% inhibitory concentration (IC50) and its confidence intervals. The two methods were observed to have similar reproducibilities, but the pLDH ELISA demonstrated a higher sensitivity. The high correlation (r = 0.98) and the high phenotypic agreement (κ = 0.88) between the two methods allowed comparison by determination of the IC50s. Recently collected Plasmodium falciparum African isolates were tested by pLDH ELISA and showed drug resistance or decreased susceptibilities of 62% to chloroquine and 11.5% to the active metabolite of amodiaquine. No decreased susceptibility to lumefantrine or the active metabolite of artemisinin was detected. The availability of this simple and highly sensitive pLDH immunodetection assay will provide an easier method for drug susceptibility testing of malaria parasites.

scholarly journals Identification of the bud emergence gene BEM4 and its interactions with rho-type GTPases in Saccharomyces cerevisiae.

1996 ◽  
Vol 16 (8) ◽  
pp. 4387-4395 ◽  
Author(s):  
D Mack ◽  
K Nishimura ◽  
B K Dennehey ◽  
T Arbogast ◽  
J Parkinson ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Synthetic Lethality ◽  
Cell Polarization ◽  
Growth Defect ◽  
Nucleotide Exchange ◽  
Loss Of Function ◽  
Multicopy Suppressor ◽  
Bud Emergence ◽  
Multicopy Suppressors ◽  
Multiple Copies

The Rho-type GTPase Cdc42p is required for cell polarization and bud emergence in Saccharomyces cerevisiae. To identify genes whose functions are linked to CDC42, we screened for (i) multicopy suppressors of a Ts- cdc42 mutant, (ii) mutants that require multiple copies of CDC42 for survival, and (iii) mutations that display synthetic lethality with a partial-loss-of-function allele of CDC24, which encodes a guanine nucleotide exchange factor for Cdc42p. In all three screens, we identified a new gene, BEM4. Cells from which BEM4 was deleted were inviable at 37 degrees C. These cells became unbudded, large, and round, consistent with a model in which Bem4p acts together with Cdc42p in polarity establishment and bud emergence. In some strains, the ability of CDC42 to serve as a multicopy suppressor of the Ts- growth defect of deltabem4 cells required co-overexpression of Rho1p, which is an essential Rho-type GTPase necessary for cell wall integrity. This finding suggests that Bem4p also affects Rho1p function. Bem4p displayed two-hybrid interactions with Cdc42p, Rho1p, and two of the three other known yeast Rho-type GTPases, suggesting that Bem4p can interact with multiple Rho-type GTPases. Models for the role of Bem4p include that it serves as a chaperone or modulates the interaction of these GTPases with one or more of their targets or regulators.

scholarly journals Pooled Sequencing and Rare Variant Association Tests for Identifying the Determinants of Emerging Drug Resistance in Malaria Parasites

2015 ◽  
Vol 32 (4) ◽  
pp. 1080-1090 ◽  
Author(s):  
Ian H. Cheeseman ◽  
Marina McDew-White ◽  
Aung Pyae Phyo ◽  
Kanlaya Sriprawat ◽  
François Nosten ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Rare Variant ◽  
Malaria Parasites ◽  
Rare Variant Association ◽  
Association Tests ◽  
Pooled Sequencing

scholarly journals OVERVIEW OF MALARIA PARASITE AND ITS PREVENTION IN INDIA

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Adil Raza ◽  
Megha Chaudhary ◽  
Sonika Devi
Keyword(s):  
Red Blood Cells ◽  
Peripheral Blood ◽  
Blood Cells ◽  
Malaria Parasite ◽  
Plasmodium Species ◽  
Peripheral Blood Smear ◽  
Infected Mosquito ◽  
Protozoan Parasites ◽  
Malaria Parasites ◽  
Genus Plasmodium

Background: Malaria is a systematic disease caused by a parasite called Plasmodium which is transmitted into the human blood via female Anopheles mosquito. Malaria in humans is caused by four species of protozoan parasites of the genus Plasmodium: P. falciparum, P. vivax, P. ovale, and P. malariae. The parasite enters the human body through a mosquito bite and travel to the very crucial organ, the liver, where they multiply and come back to the bloodstream and destroy red blood cells. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases it can cause yellow skin, seizures, coma, or death. Symptoms usually begin ten to fifteen days after being bitten by an infected mosquito. In those who have recently survived an infection, reinfection usually causes milder symptoms. Objectives: Isolation of different species of malaria parasites. The prevalence of malaria parasite in India. Methods: The procedure follows these steps: collection of peripheral blood, staining of smear with Leishman’s stain and examination of red blood cells for malaria parasites under the microscope. Results: We observed the plasmodium species in peripheral blood smear. Conclusion: Worldwide, the number of cases of malaria caused by Plasmodium falciparum, the most dangerous species of the parasite, is on the rise.

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