scholarly journals Probing Changes in Ca2+-Induced Interaction Forces between Calmodulin and Melittin by Atomic Force Microscopy

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 906
Author(s):  
Sheng Huang ◽  
Jianhua Wang ◽  
Heng Sun ◽  
Yuna Fu ◽  
Yan Wang
Keyword(s):  
Atomic Force Microscopy ◽  
Biological Macromolecules ◽  
Dependent Manner ◽  
Adhesion Forces ◽  
Concentration Dependent Manner ◽  
Force Microscopy ◽  
Calmodulin Binding ◽  
Atomic Force ◽  
Relationship Of ◽  
Configuration Changes

Mechanobiology studies the means by which physical forces and mechanical properties change intra- or inter- biological macromolecules. Calmodulin (CaM) is involved in physiological activities and various metabolic processes in eukaryotic cells. Although the configuration changes in the interaction between calmodulin and melittin have been studied, the biomechanical relationship of their interaction has rarely been explored. Here, we measured the adhesion forces between calmodulin and melittin in solutions of gradient concentration of calcium ions using atomic force microscopy (AFM). We found that the specific (Fi) and nonspecific (F0) adhesion forces between single melittin and calmodulin in a PBS solution were 69.4 ± 5.0 and 29.3 ± 8.9 pN, respectively. In the presence of 10−7 to 10−3 M Ca2+ PBS solution, the Fi increased significantly to 93.8 ± 5.0, 139.9 ± 9.0, 140.4 ± 9.7, 171.5 ± 9.0, and 213.3 ± 17.8 pN, indicating that the unbinding force between melittin and calmodulin increased in the presence of Ca2+ in a concentration-dependent manner. These findings demonstrated that biomechanical studies based on AFM could help us better understand the melittin/calmodulin-binding processes in the presence of calcium and help us design and screen peptide drugs based on calmodulin.

Nanoscale adhesion forces between the fungal pathogen Candida albicans and macrophages

2016 ◽  
Vol 1 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Sofiane El-Kirat-Chatel ◽  
Yves F. Dufrêne
Keyword(s):  
Atomic Force Microscopy ◽  
Candida Albicans ◽  
Immune Cells ◽  
Fungal Pathogen ◽  
Fungal Pathogens ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force

We establish atomic force microscopy as a new nanoscopy platform for quantifying the forces between fungal pathogens and immune cells.

scholarly journals A modular atomic force microscopy approach reveals a large range of hydrophobic adhesion forces among bacterial members of the leaf microbiota

2019 ◽  
Vol 13 (7) ◽  
pp. 1878-1882 ◽  
Author(s):  
Maximilian Mittelviefhaus ◽  
Daniel B. Müller ◽  
Tomaso Zambelli ◽  
Julia A. Vorholt
Keyword(s):  
Atomic Force Microscopy ◽  
Large Range ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force

Atomic force microscopy measurement of leukocyte-endothelial interaction

2004 ◽  
Vol 286 (1) ◽  
pp. H359-H367 ◽  
Author(s):  
Xiaohui Zhang ◽  
Aileen Chen ◽  
Dina De Leon ◽  
Hong Li ◽  
Eisei Noiri ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Inflammatory Diseases ◽  
Leukocyte Adhesion ◽  
Umbilical Vein ◽  
Quantitative Measure ◽  
Dependent Manner ◽  
Average Force ◽  
Force Microscopy ◽  
Atomic Force ◽  
Umbilical Vein Endothelial Cells

Leukocyte adhesion to vascular endothelium is a key initiating step in the pathogenesis of many inflammatory diseases. In this study, we present real-time force measurements of the interaction between monocytic human promyelocytic leukemia cells (HL-60) cells and a monolayer of human umbilical vein endothelial cells (HUVECs) by using atomic force microscopy (AFM). The detachment of HL-60-HUVEC conjugates involved a series of rupture events with force transitions of 40–100 pN. The integrated force of these rupture events provided a quantitative measure of the adhesion strength on a whole cell level. The AFM measurements revealed that HL-60 adhesion is heightened in the borders formed by adjacent HUVECs. The average force and mechanical work required to detach a single HL-60 from the borders of a tumor necrosis factor-α-activated HUVEC layer were twice as high as those of the HUVEC bodies. HL-60 adhesion to the monolayer was significantly reduced by a monoclonal antibody against β1-integrins and partially inhibited by antibodies against selectins ICAM-1 and VCAM-1 but was not affected by anti-αVβ3. Interestingly, adhesion was also inhibited in a dose-dependent manner (IC50≈ 100 nM) by a cyclic arginine-glycine-aspartic acid (cRGD) peptide. This effect was mediated via interfering with the VLA-4-VCAM-1 binding. In parallel measurements, transmigration of HL-60 cells across a confluent HUVEC monolayer was inhibited by the cRGD peptide and by both anti-β1and anti-αVβ3antibodies. In conclusion, these data demonstrate the role played by β1-integrins in leukocyte-endothelial adhesion and transmigration and the role played by αVβ3in transmigration, thus underscoring the high efficacy of cRGD peptide in blocking both the adhesion and transmigration of monocytes.

scholarly journals Adhesion force mapping on wood by atomic force microscopy: influence of surface roughness and tip geometry

2016 ◽  
Vol 3 (10) ◽  
pp. 160248 ◽  
Author(s):  
X. Jin ◽  
B. Kasal
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Wood Surface ◽  
Adhesion Force ◽  
Data Interpretation ◽  
Natural Fibre ◽  
Force Distribution ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force

This study attempts to address the interpretation of atomic force microscopy (AFM) adhesion force measurements conducted on the heterogeneous rough surface of wood and natural fibre materials. The influences of wood surface roughness, tip geometry and wear on the adhesion force distribution are examined by cyclic measurements conducted on wood surface under dry inert conditions. It was found that both the variation of tip and surface roughness of wood can widen the distribution of adhesion forces, which are essential for data interpretation. When a common Si AFM tip with nanometre size is used, the influence of tip wear can be significant. Therefore, control experiments should take the sequence of measurements into consideration, e.g. repeated experiments with used tip. In comparison, colloidal tips provide highly reproducible results. Similar average values but different distributions are shown for the adhesion measured on two major components of wood surface (cell wall and lumen). Evidence supports the hypothesis that the difference of the adhesion force distribution on these two locations was mainly induced by their surface roughness.

Adhesion Forces between LewisX Determinant Antigens as Measured by Atomic Force Microscopy

2001 ◽  
Vol 40 (16) ◽  
pp. 3052-3055 ◽  
Author(s):  
Christophe Tromas ◽  
Javier Rojo ◽  
Jesús M. de la Fuente ◽  
Africa G. Barrientos ◽  
Ricardo García ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Atomic force microscopy of DNA and bacteriophage in air, water and propanol: the role of adhesion forces

1993 ◽  
Vol 21 (5) ◽  
pp. 1117-1123 ◽  
Author(s):  
Y.L. Lyubchenko ◽  
P.I. Oden ◽  
D. Lampner ◽  
S.M. Lindsay ◽  
K.A. Dunker
Keyword(s):  
Atomic Force Microscopy ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Challenges of Working with Active Pharmaceutical Ingredients to Measure Adhesion Forces by Atomic Force Microscopy

2011 ◽  
Vol 17 (S2) ◽  
pp. 1128-1129
Author(s):  
A Vogt ◽  
J Reddel
Keyword(s):  
Atomic Force Microscopy ◽  
Active Pharmaceutical Ingredients ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Pharmaceutical Ingredients ◽  
Atomic Force

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

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