scholarly journals Do we really need sub-micron resolution to analyse single cell molecular features through vibrational spectroscopy? A pilot study using Plasmodium falciparum-infected Human Erythrocytes

2021 ◽  
Author(s):  
Agnieszka Banas ◽  
Krzysztof Banas ◽  
Trang Thi Thu Chu ◽  
Renugah Naidu ◽  
Paul Edward Hutchinson ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Spectroscopic Characterization ◽  
Label Free ◽  
Parasite Life Cycle ◽  
Major Life ◽  
Complex Processes ◽  
Molecular Features ◽  
Promising Tool ◽  
Heterogeneous Objects ◽  
Infected Rbcs

Abstract Malaria is one of the major life-threatening diseases to afflict humanity with an estimated 228 million cases worldwide in 2018. There exists no approved Malaria vaccine on the market yet, partly due to the complexity of the parasite life cycle and the vast repertoire of polymorphic proteins they express during different stages of development. In this work, we have tested two emerging spectroscopic approaches: Optical Photothermal Infrared (O-PTIR) spectroscopy and Atomic Force Microscopy combined with infrared spectroscopy (AFM-IR) in contrast to the more traditional Fourier Transform InfraRed (FTIR) microspectroscopy which has emerged recently as a new promising tool to provide label-free analysis of cell and tissue sections. Examples of chemical spatial distributions of selected bands and spectra for Plasmodium falciparum infected RBCs collected with the three modalities are presented and compared together with advantages and limitations of each method. Based on these results, it appears that O-PTIR and AFM-IR techniques can be explored as powerful tools for the analysis of cells and ipso facto, these methods can help in better understanding complex processes occurring within heterogeneous objects such as infected RBC due to their superior spatial resolution in comparison with traditional approaches for infrared spectroscopic characterization.

Biochemical characterization of Plasmodium falciparum CTP:phosphoethanolamine cytidylyltransferase shows that only one of the two cytidylyltransferase domains is active

2013 ◽  
Vol 450 (1) ◽  
pp. 159-167 ◽  
Author(s):  
Sweta Maheshwari ◽  
Marina Lavigne ◽  
Alicia Contet ◽  
Blandine Alberge ◽  
Emilie Pihan ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Cellular Localization ◽  
Biochemical Characterization ◽  
De Novo ◽  
Membrane Lipids ◽  
Polyclonal Antibodies ◽  
Homology Modelling ◽  
Site Directed Mutagenesis ◽  
Recombinant Enzymes ◽  
Parasite Life Cycle

The intra-erythrocytic proliferation of the human malaria parasite Plasmodium falciparum requires massive synthesis of PE (phosphatidylethanolamine) that together with phosphatidylcholine constitute the bulk of the malaria membrane lipids. PE is mainly synthesized de novo by the CDP:ethanolamine-dependent Kennedy pathway. We previously showed that inhibition of PE biosynthesis led to parasite death. In the present study we characterized PfECT [P. falciparum CTP:phosphoethanolamine CT (cytidylyltransferase)], which we identified as the rate-limiting step of the PE metabolic pathway in the parasite. The cellular localization and expression of PfECT along the parasite life cycle were studied using polyclonal antibodies. Biochemical analyses showed that the enzyme activity follows Michaelis–Menten kinetics. PfECT is composed of two CT domains separated by a linker region. Activity assays on recombinant enzymes upon site-directed mutagenesis revealed that the N-terminal CT domain was the only catalytically active domain of PfECT. Concordantly, three-dimensional homology modelling of PfECT showed critical amino acid differences between the substrate-binding sites of the two CT domains. PfECT was predicted to fold as an intramolecular dimer suggesting that the inactive C-terminal domain is important for dimer stabilization. Given the absence of PE synthesis in red blood cells, PfECT represents a potential antimalarial target opening the way for a rational conception of bioactive compounds.

scholarly journals Increased nicotinamide adenine dinucleotide content and synthesis in Plasmodium falciparum-infected human erythrocytes

Blood ◽  
1990 ◽  
Vol 75 (8) ◽  
pp. 1705-1710 ◽  
Author(s):  
CR Zerez ◽  
EF Jr Roth ◽  
S Schulman ◽  
KR Tanaka
Keyword(s):  
Plasmodium Falciparum ◽  
Nicotinic Acid ◽  
Nicotinamide Adenine Dinucleotide ◽  
Biosynthetic Pathway ◽  
Pentose Phosphate ◽  
Nicotinamide Adenine ◽  
Nicotinamide Phosphoribosyltransferase ◽  
Nad Synthesis ◽  
Infected Rbcs ◽  
Nicotinic Acid Phosphoribosyltransferase

Abstract Plasmodium falciparum-infected red blood cells (RBCs) are characterized by increases in the activity of glycolytic enzymes. Because nicotinamide adenine dinucleotide (NAD) and NAD phosphate (NADP) are cofactors in the reactions of glycolysis and pentose phosphate shunt, we have examined NAD and NADP content in P. falciparum-infected RBCs. Although NADP content was not significantly altered, NAD content was increased approximately 10-fold in infected RBCs (66% parasitemia) compared with uninfected control RBCs. To determine the mechanism for the increase in NAD content, we examined the activity of several NAD biosynthetic enzymes. It is known that normal human RBCs make NAD exclusively from nicotinic acid and lack the capacity to make NAD from nicotinamide. We demonstrate that infected RBCs have readily detectable nicotinamide phosphoribosyltransferase (NPRT), the first enzyme in the NAD biosynthetic pathway that uses nicotinamide, and abundant nicotinamide deamidase, the enzyme that converts nicotinamide to nicotinic acid, thereby indicating that infected RBCs can make NAD from nicotinamide. In addition, infected RBCs have a threefold increase in nicotinic acid phosphoribosyltransferase (NAPRT), the first enzyme in the NAD biosynthetic pathway that uses nicotinic acid. Thus, the increase in NAD content in P falciparum-infected RBCs appears to be mediated by increases in NAD synthesis from both nicotinic acid and nicotinamide.

scholarly journals Ultrasensitive and label-free biosensor for the detection of Plasmodium falciparum histidine-rich protein II in saliva

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Gita V. Soraya ◽  
Chathurika D. Abeyrathne ◽  
Christelle Buffet ◽  
Duc H. Huynh ◽  
Shah Mukim Uddin ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Elimination ◽  
Point Of Care ◽  
Turnaround Time ◽  
Label Free ◽  
Global Public Health ◽  
Interdigitated Electrode ◽  
Sensor Platform ◽  
Electrode Sensor ◽  
Phosphate Buffered Saline

AbstractMalaria elimination is a global public health priority. To fulfil the demands of elimination diagnostics, we have developed an interdigitated electrode sensor platform targeting the Plasmodium falciparum Histidine Rich Protein 2 (PfHRP2) protein in saliva samples. A protocol for frequency-specific PfHRP2 detection in phosphate buffered saline was developed, yielding a sensitivity of 2.5 pg/mL based on change in impedance magnitude of the sensor. This protocol was adapted and optimized for use in saliva with a sensitivity of 25 pg/mL based on change in resistance. Further validation demonstrated detection in saliva spiked with PfHRP2 from clinical isolates in 8 of 11 samples. With a turnaround time of ~2 hours, the label-free platform based on impedance sensors has the potential for miniaturization into a point-of-care diagnostic device for malaria elimination.

scholarly journals Combining Electrostatic, Hindrance and Diffusive Effects for Predicting Particle Transport and Separation Efficiency in Deterministic Lateral Displacement Microfluidic Devices

Biosensors ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 126
Author(s):  
Valentina Biagioni ◽  
Giulia Balestrieri ◽  
Alessandra Adrover ◽  
Stefano Cerbelli
Keyword(s):  
Particle Transport ◽  
Separation Efficiency ◽  
Lateral Displacement ◽  
Operating Conditions ◽  
Separation Performance ◽  
Label Free ◽  
Deterministic Lateral Displacement ◽  
Promising Tool ◽  
Label Free Detection ◽  
Diffusive Effects

Microfluidic separators based on Deterministic Lateral Displacement (DLD) constitute a promising technique for the label-free detection and separation of mesoscopic objects of biological interest, ranging from cells to exosomes. Owing to the simultaneous presence of different forces contributing to particle motion, a feasible theoretical approach for interpreting and anticipating the performance of DLD devices is yet to be developed. By combining the results of a recent study on electrostatic effects in DLD devices with an advection–diffusion model previously developed by our group, we here propose a fully predictive approach (i.e., ideally devoid of adjustable parameters) that includes the main physically relevant effects governing particle transport on the one hand, and that is amenable to numerical treatment at affordable computational expenses on the other. The approach proposed, based on ensemble statistics of stochastic particle trajectories, is validated by comparing/contrasting model predictions to available experimental data encompassing different particle dimensions. The comparison suggests that at low/moderate values of the flowrate the approach can yield an accurate prediction of the separation performance, thus making it a promising tool for designing device geometries and operating conditions in nanoscale applications of the DLD technique.

scholarly journals Andrographolide effect on both Plasmodium falciparum infected and non infected RBCs membranes

2015 ◽  
Vol 8 (7) ◽  
pp. 507-512 ◽  
Author(s):  
O.I. Zaid ◽  
R. Abd Majid ◽  
M.N. Sabariah ◽  
M.S. Hasidah ◽  
K. Al-Zihiry ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Infected Rbcs

scholarly journals The Association of High Prevalence of Trophozoites in Peripheral Blood with Lower Antibody Response toP. falciparumInfected Erythrocytes among Asymptomatic Children in Sudan

2016 ◽  
Vol 2016 ◽  
pp. 1-4
Author(s):  
Sara N. Mohamed ◽  
Dina A. Hassan ◽  
Abdelrahim M. El Hussein ◽  
Ihssan M. Osman ◽  
Muntasir E. Ibrahim ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Plasmodium Falciparum ◽  
Peripheral Blood ◽  
Surface Antigens ◽  
Igg Antibodies ◽  
Autologous Plasma ◽  
Variant Surface Antigens ◽  
Asymptomatic Children ◽  
Infected Rbcs ◽  
The Mean

Background. The most prominent variant surface antigens (VSAs) ofPlasmodium falciparumare the var gene-encodedPlasmodium falciparumerythrocyte membrane protein 1 (PfEMP1) family, which serves as a parasite-sequestering ligand to endothelial cells. In this study we have examined the antibody reactivity of autologous plasma from symptomatic and asymptomatic malaria infected children against the infected erythrocytes’ surface antigens using flow cytometry.Methods. Ethidium-bromide-labelled erythrocytic mature forms ofP. falciparumparasites obtained from symptomatic and asymptomatic children were sequentially incubated with autologous plasma and fluorescein isothiocyanate-conjugated (FITC) antihuman IgG. Plasma antibody reactivity was detected by flow cytometry.Results. Asymptomatic children had more prevalence of trophozoites in peripheral blood (66%) compared to symptomatic children (16%),p=0.002. The mean percentage of infected RBCs reacting with autologous sera was 89.78 among symptomatic children compared to 79.62 among asymptomatic children (p=0.09). Moreover, the mean fluorescence intensity (MFI) in the asymptomatic was significantly higher compared to symptomatic children (pvalue = 0.040).Conclusion. Variant surface antigens onPlasmodium falciparuminfected RBCs from symptomatic malaria children tend to be better recognized by IgG antibodies. This may suggest a role of some IgG antibodies in severity of malaria.

scholarly journals An open dataset of Plasmodium falciparum genome variation in 7,000 worldwide samples

2021 ◽  
Vol 6 ◽  
pp. 42
Author(s):  
◽  
Ambroise Ahouidi ◽  
Mozam Ali ◽  
Jacob Almagro-Garcia ◽  
Alfred Amambua-Ngwa ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Copy Number Variants ◽  
Open Data ◽  
Nucleotide Polymorphisms ◽  
Parasite Life Cycle ◽  
Genome Variation ◽  
Data Resource ◽  
Genomic Epidemiology ◽  
Accelerate Development ◽  
Almost All

MalariaGEN is a data-sharing network that enables groups around the world to work together on the genomic epidemiology of malaria. Here we describe a new release of curated genome variation data on 7,000 Plasmodium falciparum samples from MalariaGEN partner studies in 28 malaria-endemic countries. High-quality genotype calls on 3 million single nucleotide polymorphisms (SNPs) and short indels were produced using a standardised analysis pipeline. Copy number variants associated with drug resistance and structural variants that cause failure of rapid diagnostic tests were also analysed.  Almost all samples showed genetic evidence of resistance to at least one antimalarial drug, and some samples from Southeast Asia carried markers of resistance to six commonly-used drugs. Genes expressed during the mosquito stage of the parasite life-cycle are prominent among loci that show strong geographic differentiation. By continuing to enlarge this open data resource we aim to facilitate research into the evolutionary processes affecting malaria control and to accelerate development of the surveillance toolkit required for malaria elimination.

scholarly journals Resistance to Plasmodium falciparum in sickle cell trait erythrocytes is driven by oxygen-dependent growth inhibition

2018 ◽  
Vol 115 (28) ◽  
pp. 7350-7355 ◽  
Author(s):  
Natasha M. Archer ◽  
Nicole Petersen ◽  
Martha A. Clark ◽  
Caroline O. Buckee ◽  
Lauren M. Childs ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Growth Inhibition ◽  
Sickle Cell ◽  
Sickle Cell Trait ◽  
Low Oxygen ◽  
Partial Protection ◽  
Infected Rbcs ◽  
Specific Stage ◽  
Mechanistic Basis ◽  
Dependent Growth

Sickle cell trait (AS) confers partial protection against lethal Plasmodium falciparum malaria. Multiple mechanisms for this have been proposed, with a recent focus on aberrant cytoadherence of parasite-infected red blood cells (RBCs). Here we investigate the mechanistic basis of AS protection through detailed temporal mapping. We find that parasites in AS RBCs maintained at low oxygen concentrations stall at a specific stage in the middle of intracellular growth before DNA replication. We demonstrate that polymerization of sickle hemoglobin (HbS) is responsible for this growth arrest of intraerythrocytic P. falciparum parasites, with normal hemoglobin digestion and growth restored in the presence of carbon monoxide, a gaseous antisickling agent. Modeling of growth inhibition and sequestration revealed that HbS polymerization-induced growth inhibition following cytoadherence is the critical driver of the reduced parasite densities observed in malaria infections of individuals with AS. We conclude that the protective effect of AS derives largely from effective sequestration of infected RBCs into the hypoxic microcirculation.

A transgenic Plasmodium falciparum NF54 strain that expresses GFP–luciferase throughout the parasite life cycle

2012 ◽  
Vol 186 (2) ◽  
pp. 143-147 ◽  
Author(s):  
Ashley M. Vaughan ◽  
Sebastian A. Mikolajczak ◽  
Nelly Camargo ◽  
Viswanathan Lakshmanan ◽  
Mark Kennedy ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Life Cycle ◽  
Parasite Life Cycle

scholarly journals The Lipid Moiety of Haemozoin (Malaria Pigment) andP. falciparumParasitised Red Blood Cells Bind Synthetic and Native Endothelin-1

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Nicoletta Basilico ◽  
Silvia Parapini ◽  
Francesca Sisto ◽  
Fausta Omodeo-Salè ◽  
Paolo Coghi ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Vascular Endothelium ◽  
Blood Cells ◽  
Vascular Tone ◽  
Amino Acid Peptide ◽  
Lipid Moiety ◽  
Infected Rbcs ◽  
Malaria Pigment ◽  
Dose Dependent

Endothelin1 (ET-1) is a 21-amino acid peptide produced by the vascular endothelium under hypoxia, that acts locally as regulator of vascular tone and inflammation. The role of ET-1 inPlasmodium falciparummalaria is unknown, although tissue hypoxia is frequent as a result of the cytoadherence of parasitized red blood cell (pRBC) to the microvasculature. Here, we show that both synthetic and endothelial-derived ET-1 are removed by parasitized RBC (D10 and W2 strains, chloroquine sensitive, and resistant, resp.) and native haemozoin (HZ, malaria pigment), but not by normal RBC, delipidized HZ, or synthetic beta-haematin (BH). The effect is dose dependent, selective for ET-1, but not for its precursor, big ET-1, and not due to the proteolysis of ET-1. The results indicate that ET-1 binds to the lipids moiety of HZ and membranes of infected RBCs. These findings may help understanding the consequences of parasite sequestration in severe malaria.

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