scholarly journals Dissection of Plasmodium falciparum developmental stages with multiple imaging methods

2020 ◽  
Author(s):  
Katharina Preißinger ◽  
Beáta Vértessy ◽  
István Kézsmárki ◽  
Miklós Kellermayer
Keyword(s):  
Plasmodium Falciparum ◽  
Developmental Stages ◽  
Imaging Study ◽  
Close Correlation ◽  
Parasite Development ◽  
Force Microscopy ◽  
Global Challenge ◽  
Atomic Force ◽  
Multiple Imaging ◽  
Infected Rbcs

Efficient malaria treatment is a global challenge, requiring in-depth view into the maturation of malaria parasites during the intraerythrocytic cycle. Exploring structural and functional variations of the parasites through the intraerythrocytic stages and their impact on red blood cell (RBCs) is a cornerstone of antimalarial drug development. In order to trace such changes in fine steps of parasite development, we performed an imaging study of RBCs infected by Plasmodium falciparum, using atomic force microscopy (AFM) and total internal reflection fluorescence microscopy (TIRF), further supplemented with bright field microscopy for the direct assignment of the stages. This multifaceted imaging approach allows to reveal structure–functionality relations via correlations of the parasite maturation with morphological and fluorescence properties of the stages. We established identification patterns characteristic to the different parasite stages based on the height profile of infected RBCs, as obtained by AFM, which show close correlation with typical fluorescence (TIRF) maps of RBCs. Furthermore, we found that hemozoin crystals exhibit a strong optical contrast by quenching fluorescence. We demonstrate that these topographic and optical features also provide a tool to locate the hemozoin crystals within the RBCs and, in turn, to follow their growth.

scholarly journals Stage-Dependent Topographical and Optical Properties of Plasmodium Falciparum-Infected Red Blood Cells

2021 ◽  
Author(s):  
Katharina Preißinger ◽  
Beáta Vértessy ◽  
István Kézsmárki ◽  
Miklós Kellermayer ◽  
Petra Molnár
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Imaging Study ◽  
Close Correlation ◽  
Functional Changes ◽  
Force Microscopy ◽  
Atomic Force ◽  
Infected Rbcs ◽  
Bright Field Microscopy

Abstract Efficient malaria treatment is a major healthcare challenge. Addressing this challenge requires in-depth understanding of malaria parasite maturation during the intraerythrocytic cycle. Exploring the structural and functional changes of the parasite through the intraerythrocytic stages and their impact on red blood cells (RBCs) is a cornerstone of antimalarial drug development. In order to precisely trace such changes, we performed a thorough imaging study of RBCs infected by Plasmodium falciparum, by using atomic force microscopy (AFM) and total internal reflection fluorescence microscopy (TIRF) supplemented with bright field microscopy for stage assignment. This multifaceted imaging approach allows to reveal structure–function relations via correlations of the parasite maturation with morphological and fluorescence properties of the stages. We established diagnostic patterns characteristic to the parasite stages based on the topographical profile of infected RBCs, which show close correlation with their fluorescence (TIRF) map. Furthermore, we found that hemozoin crystals exhibit a strong optical contrast, possibly due to the quenching of fluorescence. The topographical and optical features provide a tool for locating the hemozoin crystals within the RBCs and following their growth.

Molecular factors that are associated with early developmental arrest of intraerythrocytic Plasmodium falciparum

2013 ◽  
Vol 59 (7) ◽  
pp. 485-493 ◽  
Author(s):  
Hiroko Asahi ◽  
Mohammed Essa Marghany Tolba ◽  
Masanobu Tanabe ◽  
Hiroshi Ohmae
Keyword(s):  
Plasmodium Falciparum ◽  
Fatty Acid ◽  
Developmental Stages ◽  
Copper Ions ◽  
Copper Ion ◽  
Merozoite Surface Protein ◽  
Parasite Development ◽  
Ring Stage ◽  
Critical Function ◽  
Developmental Arrest

Malaria continues to be a devastating disease. We investigated the factors that control intraerythrocytic development of the parasite Plasmodium falciparum by using a chemically defined medium (CDM) containing non-esterified fatty acid(s) (NEFA) and phospholipids with specific fatty acid moieties, to identify substances crucial for parasite development. Different NEFAs in the CDM played distinct roles by altering the development of the parasite at various stages, with effects ranging from complete growth to growth arrest at the ring stage. We used genome-wide transcriptome profiling to identify genes that were differentially expressed among the different developmental stages of the parasite, cultured in the presence of various NEFAs. We predicted 26 transcripts that were associated with the suppression of schizogony, of which 5 transcripts, including merozoite surface protein 2, a putative DEAD/DEAH box RNA helicase, serine repeat antigen 3, a putative copper channel, and palmitoyl acyltransferase, were particularly associated with blockage of trophozoite progression from the ring stage. Furthermore, the involvement of copper ions in developmental arrest was detected by copper-ion-chelating methods, implying a critical function of copper homeostasis in the early growth stage of the parasite. These results should help to elucidate the mechanisms behind the development of P. falciparum.

scholarly journals Epitaxial Stabilization of Single-Crystal Multiferroic YCrO3 Thin Films

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2085
Author(s):  
Yogesh Sharma ◽  
Elizabeth Skoropata ◽  
Binod Paudel ◽  
Kyeong Tae Kang ◽  
Dmitry Yarotski ◽  
...  
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Magnetic Transition ◽  
Close Correlation ◽  
Layer By Layer ◽  
Epitaxial Thin Films ◽  
X Ray Diffraction ◽  
Magnetic Transition Temperature ◽  
Force Microscopy ◽  
Atomic Force

We report on the growth of stoichiometric, single-crystal YCrO3 epitaxial thin films on (001) SrTiO3 substrates using pulsed laser deposition. X-ray diffraction and atomic force microscopy reveal that the films grew in a layer-by-layer fashion with excellent crystallinity and atomically smooth surfaces. Magnetization measurements demonstrate that the material is ferromagnetic below 144 K. The temperature dependence of dielectric permittivity shows a characteristic relaxor-ferroelectric behavior at TC = 375–408 K. A dielectric anomaly at the magnetic transition temperature indicates a close correlation between magnetic and electric order parameters in these multiferroic YCrO3 films. These findings provide guidance to synthesize rare-earth, chromite-based multifunctional heterostructures and build a foundation for future studies on the understanding of magnetoelectric effects in similar material systems.

Continuous force-displacement relationships for the human red blood cell at different erythrocytic developmental stages ofPlasmodium falciparummalaria parasite

2004 ◽  
Vol 844 ◽  
Author(s):  
John P. Mills ◽  
Lan Qie ◽  
Ming Dao ◽  
Kevin S. W. Tan ◽  
Chwee Teck Lim ◽  
...  
Keyword(s):  
Blood Cell ◽  
Optical Tweezers ◽  
Red Blood Cell ◽  
Mechanical Response ◽  
Developmental Stages ◽  
Three Dimensional ◽  
Parasite Development ◽  
Human Red Blood Cells ◽  
Infected Rbcs ◽  
Order Of Magnitude

ABSTRACTPrior work involving either aspiration of infected cells into micropipette under suction pressure or deformation in laminar shear flow revealed that the malaria parasitePlasmodium (P.) falciparumcould result in significant stiffening of infected human red blood cells (RBCs). In this paper, we present optical tweezers studies of progressive changes to nonlinear mechanical response of infected RBCs at different developmental stages ofP. falciparum.From early ring stage to late trophozoite and schizont stages, up to an order of magnitude increase in shear modulus was found under controlled mechanical loading by combining experiments with three-dimensional computational simulations. These results provide novel approaches to study changes in mechanical deformability in the advanced stages of parasite development in the erythrocyte, and suggest a significantly greater stiffening of the red blood cell due toP. falciparuminvasion than that considered from previous studies.

scholarly journals Cathodoluminescence Wavelength Imaging Study of Clustering in InAs/GaAs Self-Assembled Quantum Dots

2000 ◽  
Vol 618 ◽  
Author(s):  
D. H. Rich ◽  
C. Zhang ◽  
I. Mukhametzhanov ◽  
A. Madhukar
Keyword(s):  
Quantum Dots ◽  
Spatial Scale ◽  
Size Distribution ◽  
Imaging Study ◽  
Island Growth ◽  
Spectral Lineshape ◽  
Force Microscopy ◽  
Self Organized ◽  
Atomic Force ◽  
Self Assembled

ABSTRACTCathodoluminescence wavelength imaging (CLWI) of InAs/GaAs self-assembled quantum dots (SAQDs) was performed to study the spatial variation in the spectral lineshape of the broadened quantum dot (QD) ensemble. The lineshape was found to vary on a scale of ∼μm, revealing attendant variations in the size distribution of SAQD clusters on this spatial scale. Energy variations in clusters of SAQDs are found to exhibit a spatial correlation with the efficiency of luminescence and the activation energy for thermal re-emission of carriers. A reduction in the energy variation of the QD clusters occurs when the thickness of the spacer layers in vertically self-organized samples is reduced or the number of stacks is increased. SAQDs were also prepared by punctuated island growth (PIG), in which deposition of the total desired amount is broken into two or more stages each separated by time delays. CLWI reveals a reduced variation in the energy of the dominant CL emission on a ∼μm spatial scale, correlating with a narrower size distribution of larger QDs for PIG, as measured in atomic force microscopy.

scholarly journals Atomic defect classification of the H–Si(100) surface through multi-mode scanning probe microscopy

2020 ◽  
Vol 11 ◽  
pp. 1346-1360 ◽  
Author(s):  
Jeremiah Croshaw ◽  
Thomas Dienel ◽  
Taleana Huff ◽  
Robert Wolkow
Keyword(s):  
Surface Defects ◽  
Hydrogen Atoms ◽  
Force Microscopy ◽  
Surface Hydrogen ◽  
Atomic Force ◽  
Multiple Imaging ◽  
Tunnelling Microscopy ◽  
Imaging Mode

The combination of scanning tunnelling microscopy (STM) and non-contact atomic force microscopy (nc-AFM) allows enhanced extraction and correlation of properties not readily available via a single imaging mode. We demonstrate this through the characterization and classification of several commonly found defects of the hydrogen-terminated silicon (100)-2 × 1 surface (H–Si(100)-2 × 1) by using six unique imaging modes. The H–Si surface was chosen as it provides a promising platform for the development of atom scale devices, with recent work showing their creation through precise desorption or placement of surface hydrogen atoms. While samples with relatively large areas of the H–Si surface are routinely created using an in situ methodology, surface defects are inevitably formed reducing the area available for patterning. By probing the surface using the different interactivity afforded by either hydrogen- or silicon-terminated tips, we are able to extract new insights regarding the atomic and electronic structure of these defects. This allows for the confirmation of literature assignments of several commonly found defects, as well as proposed classifications of previously unreported and unassigned defects. By combining insights from multiple imaging modes, better understanding of their successes and shortcomings in identifying defect structures and origins is achieved. With this, we take the first steps toward enabling the creation of superior H–Si surfaces through an improved understanding of surface defects, ultimately leading to more consistent and reliable fabrication of atom scale devices.

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