Biochemistry of malaria parasite infected red blood cells by X-ray microscopy

S Kapishnikov,K Matuschewski,J Als-Nielsen,P Cloetens,F Awamu Ndonglack,Y Yang,E Pereiro,L Leiserowitz

doi:10.1038/s41598-017-00921-2

Abstract

Red blood cells infected by the malaria parasite Plasmodium falciparum are correlatively imaged by tomography using soft X-rays as well as by scanning hard nano-X-ray beam to obtain fluorescence maps of various elements such as S and Fe. In this way one can deduce the amount of Fe bound either in hemoglobin or in hemozoin crystals in the digestive vacuole of the malaria parasite as well as determine the hemoglobin concentrations in the cytosols of the red blood cell and of the parasite. Fluorescence map of K shows that in the parasite’s schizont stage the K concentration in the red blood cell cytosol is diminished by a factor of seven relative to a pristine red blood cell but the total amount of K in the infected red blood cell is the same as in the pristine red blood cell.

Highlights

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The new aspect of our method is that it combines cryo soft X-ray tomography with mapping of atomic elements in different compartments, in particular of Fe, S and K
We emphasize that S is present in the amino acids cysteine or methionine, whereas Fe is coordinated to the heme molecule

Summary

16 Number of atoms in all compartments

By segmentation of the cryo-SXT data one can determine 〈tC〉 · NM It follows from equation (2) by summation over (i, j) ∈ M within the mask that. The so-called segmentation, obtained from the soft X-ray tomography, associates each voxel (i, j, k) with a certain compartment, for example the digestive vacuole (DV), the entire parasite (P), the entire cell (RBC) or outside the cell (O). Each of these compartments, for example the parasite, is given by a three-dimensional, binary matrix, MP(i, j, k), where an element is 1 if (i, j, k) belongs to the parasite, and 0 otherwise.

Discussion

Findings

Methods