scholarly journals The erythrocyte membrane properties of beta thalassaemia heterozygotes and their consequences for Plasmodium falciparum invasion

2022 ◽  
Author(s):  
Viola Introini ◽  
Alejandro Marin-Menendez ◽  
Guilherme Nettesheim ◽  
Yen-Chun Lin ◽  
Silvia N Kariuki ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Protein ◽  
Malaria Prevalence ◽  
Membrane Properties ◽  
Membrane Tension ◽  
Protective Properties ◽  
Beta Thalassaemia ◽  
Selective Pressures ◽  
Bending Modulus ◽  
Surface Protein Expression

Malaria parasites such as Plasmodium falciparum have exerted formidable selective pressures on the human genome. Of the human genetic variants associated with malaria protection, beta thalassaemia (a haemoglobinopathy) was the earliest to be associated with malaria prevalence. However, the malaria protective properties of beta thalassaemic erythrocytes remain unclear. Here we studied the mechanics and surface protein expression of beta thalassaemia heterozygous erythrocytes, measured their susceptibility to P. falciparum invasion, and calculated the energy required for merozoites to invade them. We found invasion-relevant differences in beta thalassaemic cells versus matched controls, specifically: elevated membrane tension, reduced bending modulus, and higher levels of expression of the major invasion receptor basigin. However, these differences acted in opposition to each other with respect to their likely impact on invasion, and overall we did not observe beta thalassaemic cells to have lower P. falciparum invasion efficiency for any of the strains tested.

scholarly journals Genetic diversity of Plasmodium falciparum in Grande Comore Island

2020 ◽  
Author(s):  
Nasserdine Papa Mze ◽  
Hervé Bogreau ◽  
Cyrille K. Diedhiou ◽  
Vendela Herdell ◽  
Silai Rahamatou ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Falciparum ◽  
Public Health Problem ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Malaria Prevalence ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Grande Comore ◽  
Union Of The Comoros

Abstract Background Despite several control interventions resulting in a considerable decrease in malaria prevalence in the Union of the Comoros, the disease remains a public health problem with high transmission in Grand Comore compared to neighboring islands. In this country, only a few studies investigating the genetic diversity of Plasmodium falciparum have been performed so far. For this reason, this study aims to examine the genetic diversity of P. falciparum by studying samples collected in Grande Comore in 2012 and 2013, using merozoite surface protein 1 (msp1), merozoite surface protein 2 (msp2) and single nucleotide polymorphism (SNP) genetic markers.Methods A total of 151 positive rapid diagnostic test (RDT) samples from Grande Comore were used to extract parasite DNA. Allelic families K1, Mad20 and RO33 of the msp1 gene as well as allelic families IC3D7 and FC37 of the msp2 gene were determined by using nested PCR. Additionally, 50 out of 151 samples were genotyped to study 24 SNPs by using high resolution melting (HRM).Results Two allelic families were predominant, the K1 family of msp1 gene (55%) and the FC27 family of msp2 gene (47.4%). Among 50 samples genotyped for 24 SNPs, 42 (84%) yielded

scholarly journals Getting in shape and swimming: the role of cortical forces and membrane heterogeneity in eukaryotic cells

2017 ◽  
Author(s):  
Hao Wu ◽  
Marco Avila Ponce de León ◽  
Hans G. Othmer
Keyword(s):  
Cell Movement ◽  
Membrane Properties ◽  
Membrane Tension ◽  
Actin Cortex ◽  
Bending Modulus ◽  
Motile Cells ◽  
Cell Shapes ◽  
Direction Of Movement ◽  
Shape Changes

AbstractRecent research has shown that motile cells can adapt their mode of propulsion to the mechanical properties of the environment in which they find themselves – crawling in some environments while swimming in others. The latter can involve movement by blebbing or other cyclic shape changes, and both highly-simplified and more realistic models of these modes have been studied previously. Herein we study swimming that is driven by membrane tension gradients that arise from flows in the actin cortex underlying the membrane, and does not involve imposed cyclic shape changes. Such gradients can lead to a number of different characteristic cell shapes, and our first objective is to understand how different distributions of membrane tension influence the shape of cells in a quiescent fluid. We then analyze the effects of spatial variation in other membrane properties, and how they interact with tension gradients to determine the shape. We also study the effect of fluid-cell interactions and show how tension leads to cell movement, how the balance between tension gradients and a variable bending modulus determine the shape and direction of movement, and how the efficiency of movement depends on the properties of the fluid and the distribution of tension and bending modulus in the membrane.Dedicated to the memory of Karl P. Hadeler, a pioneer in the field of Mathematical Biology and a friend and mentor to many.

scholarly journals Genetic diversity of Plasmodium falciparum in Grande Comore Island

2020 ◽  
Author(s):  
Nasserdine Papa Mze ◽  
Hervé Bogreau ◽  
Cyrille K. Diedhiou ◽  
Vendela Herdell ◽  
Silai Rahamatou ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Falciparum ◽  
Public Health Problem ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Malaria Prevalence ◽  
Grande Comore ◽  
Union Of The Comoros ◽  
Msp2 Gene ◽  
Msp1 Gene

Abstract Background Despite several control interventions resulting in a considerable decrease in malaria prevalence in the Union of the Comoros, the disease remains a public health problem with high transmission in Grand Comore compared to neighboring islands. In this country, only a few studies investigating the genetic diversity of Plasmodium falciparum have been performed so far. For this reason, this study aims to examine the genetic diversity of P. falciparum by studying samples collected in Grande Comore in 2012 and 2013, using merozoite surface protein 1 ( msp1 ), merozoite surface protein 2 ( msp2 ) and single nucleotide polymorphism (SNP) genetic markers. Methods A total of 151 positive rapid diagnostic test (RDT) samples from Grande Comore were used to extract parasite DNA. Allelic families K1, Mad20 and RO33 of the msp1 gene as well as allelic families IC3D7 and FC37 of the msp2 gene were determined by using nested PCR. Additionally, 50 out of 151 samples were genotyped to study 24 SNPs by using high resolution melting (HRM). Results Two allelic families were predominant, the K1 family of msp1 gene (55%) and the FC27 family of msp2 gene (47.4%). Among 50 samples genotyped for 24 SNPs, 42 (84%) yielded interpretable results. Out of these isolates, 36 (85%) were genetically unique and 6 (15%) grouped into two clusters. The genetic diversity of Plasmodium falciparum calculated from msp gene ( msp1 and msp 2) and SNPs was 0.82 and 0.6 respectively. Conclusion In summary, a large genetic diversity of P. falciparum was observed in Grande Comore. This may favor persistence of malaria, and might be one of the reasons for the high malaria transmission compared to neighboring islands. Further surveillance of P. falciparum isolates, mainly through environmental management / vector control, is warranted until complete elimination is attained.

scholarly journals Protocol to measure the membrane tension and bending modulus of cells using optical tweezers and scanning electron microscopy

2021 ◽  
Vol 2 (1) ◽  
pp. 100283
Author(s):  
Pedro Pompeu ◽  
Pedro S. Lourenço ◽  
Diney S. Ether ◽  
Juliana Soares ◽  
Jefte Farias ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Tweezers ◽  
Membrane Tension ◽  
Bending Modulus ◽  
Scanning Electron

The Deformation of an Erythrocyte Under the Radiation Pressure by Optical Stretch

2006 ◽  
Vol 128 (6) ◽  
pp. 830-836 ◽  
Author(s):  
Yong-Ping Liu ◽  
Chuan Li ◽  
Kuo-Kang Liu ◽  
Alvin C. K. Lai
Keyword(s):  
Radiation Pressure ◽  
Experimental Situation ◽  
Numerical Data ◽  
Shear Stiffness ◽  
Cell Deformation ◽  
Membrane Properties ◽  
Optimization Approach ◽  
Bending Modulus ◽  
Average Shear ◽  
Good Agreement

In this paper, the mechanical properties of erythrocytes were studied numerically based upon the mechanical model originally developed by Pamplona and Calladine (ASME J. Biomech. Eng., 115, p. 149, 1993) for liposomes. The case under study is the erythrocyte stretched by a pair of laser beams in opposite directions within buffer solutions. The study aims to elucidate the effect of radiation pressure from the optical laser because up to now little is known about its influence on the cell deformation. Following an earlier study by Guck et al. (Phys. Rev. Lett., 84, p. 5451, 2000; Biophys. J., 81, p. 767, 2001), the empirical results of the radiation pressure were introduced and imposed on the cell surface to simulate the real experimental situation. In addition, an algorithm is specially designed to implement the simulation. For better understanding of the radiation pressure on the cell deformation, a large number of simulations were conducted for different properties of cell membrane. Results are first discussed parametrically and then evaluated by comparing with the experimental data reported by Guck et al. An optimization approach through minimizing the errors between experimental and numerical data is used to determine the optimal values of membrane properties. The results showed that an average shear stiffness around 4.611×10-6Nm−1, when the nondimensional ratio of shear modulus to bending modulus ranges from 10 to 300. These values are in a good agreement with those reported in literature.

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