Meet us at Arablab 2023

NanoWorld AG CEO Manfred Detterbeck is @arablab which is currently being held from 19 – 21 September 2023 at Dubai World Trade Centre.  Will we meet you there too?

Opening hours:

19 – 20 Sept: 10.00 – 18.00

21 Sept: 10.00 – 17.00

NanoWorld AFM probes CEO Manfred Detterbeck at Arablab 2023 in Dubai this week. Don't hesitate to catch up with him on the news on AFM probes when you meet him.
NanoWorld CEO Manfred Detterbeck at Arablab 2023

Cell surface fluctuations regulate early embryonic lineage sorting

In development, lineage segregation is coordinated in time and space. An important example is the mammalian inner cell mass, in which the primitive endoderm (PrE, founder of the yolk sac) physically segregates from the epiblast (EPI, founder of the fetus). While the molecular requirements have been well studied, the physical mechanisms determining spatial segregation between EPI and PrE remain elusive.*

In the article “Cell surface fluctuations regulate early embryonic lineage sorting” Ayaka Yanagida, Elena Corujo-Simon, Christopher K. Revell, Preeti Sahu, Giuliano G. Stirparo, Irene M. Aspalter, Alex K. Winkel, Ruby Peters, Henry De Belly, Davide A.D. Cassani, Sarra Achouri     Raphael Blumenfeld, Kristian Franze, Edouard Hannezo, Ewa K. Paluch, Jennifer Nichols and Kevin J. Chalut investigate the mechanical basis of EPI and PrE sorting. *

The authors find that rather than the differences in static cell surface mechanical parameters as in classical sorting models, it is the differences in surface fluctuations that robustly ensure physical lineage sorting.*

These differential surface fluctuations systematically correlate with differential cellular fluidity, which Ayaka Yanagida et al. propose together constitute a non-equilibrium sorting mechanism for EPI and PrE lineages. By combining experiments and modeling, A. Yanagida et al. identify cell surface dynamics as a key factor orchestrating the correct spatial segregation of the founder embryonic lineages.*

The surface tension of cells was measured using an Atomic Force Microscopy (AFM) based technique with a commercially available stand-alone platform for cell adhesion and cytomechanics studies mounted on an inverted confocal microscope.*

pEPI (epiblast , EPI, founder of the fetus) and pPrE (primitive endoderm, founder of the yolk sac ) tension measurements were performed using NanoWorld ARROW-TL1Au tipless silicon AFM cantilevers (nominal spring constant of 0.03 N/m).*
Sensitivity was calibrated by acquiring a force curve on a glass coverslip. Spring constant was calibrated by the thermal noise fluctuation method. Z-length parameter and setpoint force were set at 30 μm and 10 nN, respectively. Constant height mode was selected. The measurement was carried on by lowering the tipless AFM cantilever onto an empty area next to a target cell. Once the cantilever retracted (by roughly 30 μm), it was positioned above the target cell and run a compression for 200 seconds. During the constant height compression, the force acting on the AFM cantilever was recorded. After initial force relaxation, the resulting force value was used to extract surface tension.*

ES cells tension measurements were performed using the same commercial platform for cell adhesion and cytomechanics studies and a DSD2 Differential Spinning Disk both mounted on an inverted microscope.*

NanoWorld tipless silicon AFM cantilevers of the ARROW-TL1 type were chosen (nominal spring constant of 0.03 N/m). Sensitivity was calibrated by acquiring a force curve on glass. Spring constant was calibrated by the thermal noise fluctuation method. Z-length parameter and setpoint force were set at 80 μm and 4 nN, respectively. Constant height mode was selected. The measurement was carried on by lowering the tipless AFM cantilever onto an empty area next to a target cell. Once the AFM cantilever retracted (by roughly 80 μm), it was positioned above the target cell and a compression was run for 50 seconds. During the constant height compression, the force acting on the AFM cantilever was recorded. After initial force relaxation, the resulting force value was used to extract surface tension. A confocal stack was acquired using a ×40/1.1 NA water immersion objective.*

Figure 4 from Ayaka Yanagida et al. “Cell surface fluctuations regulate early embryonic lineage sorting”:Differences in ezrin-mediated surface fluctuations regulate cell sorting (A) Representative images of constitutively active Ezrin-IRES-mCherry (CA-EZR) ES cells, showing a high degree of pERM variability in the low mCherry-expressing ES cells. Surface fluctuations of single CA-EZR cells without Dox and WT H2B-BFP, and CA-EZR ES cells with or without Dox in 2i+LIF. L, M, and H indicate low, medium, and high expression of mCherry as assessed by the 3-quantiles of expression in the mCherry-expressing cells. Surface fluctuations were normalized by the mean of the Dox− surface fluctuations in each of the experiments or the mean of the WT H2B-BFP surface fluctuations. p values were calculated using one-way ANOVA, with the p values above each group representing the outcome of pairwise comparison with Dox−, and the p value above all values in CA-EZR Dox+ condition representing the comparison of all groups. (B) The surface tension of dissociated Dox-treated CA-EZR ES cells measured using the AFM technique presented in Chugh et al., 2017 is plotted against the intensity of mCherry to show that there is no correlation between CA-EZR expression and surface tension. On the right is the surface tension of dissociated WT H2B-BFP ES cells and Dox-treated CA-EZR ES cells. p value was calculated by two-way ANOVA using cell type and experimental replicate as variables. (C) θ of the homotypic doublets that can be formed from CA-EZR ES cells with or without Dox. (D) Representative images of CA-EZR ES cells and WT H2B-BFP ES cells aggregated with or without Dox. The line drawn through the center of the aggregates represents the line over which we found an intensity profile in (E). (E) Representative comparison of BFP and mCherry line scan signals in the CA-EZR and H2B-BFP ES cells aggregates with or without Dox, using the line across the images in (D). (F) Schematic showing how the radial average (dipole moment) R is calculated, along with model examples of R for distributions shown. (G) R of aggregates of CA-EZR and H2B-BFP ES cells. pEPI (epiblast , EPI, founder of the fetus) and pPrE (primitive endoderm, founder of the yolk sac ) tension measurements were performed using NanoWorld ARROW-TL1Au tipless silicon AFM cantilevers. ES cells tension measurements were performed using NanoWorld tipless silicon AFM cantilevers of the ARROW-TL1 type were chosen (nominal spring constant of 0.03 N/m).
Figure 4 from Ayaka Yanagida et al. “Cell surface fluctuations regulate early embryonic lineage sorting”:
Differences in ezrin-mediated surface fluctuations regulate cell sorting
(A) Representative images of constitutively active Ezrin-IRES-mCherry (CA-EZR) ES cells, showing a high degree of pERM variability in the low mCherry-expressing ES cells. Surface fluctuations of single CA-EZR cells without Dox and WT H2B-BFP, and CA-EZR ES cells with or without Dox in 2i+LIF. L, M, and H indicate low, medium, and high expression of mCherry as assessed by the 3-quantiles of expression in the mCherry-expressing cells. Surface fluctuations were normalized by the mean of the Dox− surface fluctuations in each of the experiments or the mean of the WT H2B-BFP surface fluctuations. p values were calculated using one-way ANOVA, with the p values above each group representing the outcome of pairwise comparison with Dox−, and the p value above all values in CA-EZR Dox+ condition representing the comparison of all groups.
(B) The surface tension of dissociated Dox-treated CA-EZR ES cells measured using the AFM technique presented in Chugh et al., 2017
is plotted against the intensity of mCherry to show that there is no correlation between CA-EZR expression and surface tension. On the right is the surface tension of dissociated WT H2B-BFP ES cells and Dox-treated CA-EZR ES cells. p value was calculated by two-way ANOVA using cell type and experimental replicate as variables.
(C) θ of the homotypic doublets that can be formed from CA-EZR ES cells with or without Dox.
(D) Representative images of CA-EZR ES cells and WT H2B-BFP ES cells aggregated with or without Dox. The line drawn through the center of the aggregates represents the line over which we found an intensity profile in (E).
(E) Representative comparison of BFP and mCherry line scan signals in the CA-EZR and H2B-BFP ES cells aggregates with or without Dox, using the line across the images in (D).
(F) Schematic showing how the radial average (dipole moment) R is calculated, along with model examples of R for distributions shown.
(G) R of aggregates of CA-EZR and H2B-BFP ES cells.

*Ayaka Yanagida, Elena Corujo-Simon, Christopher K. Revell, Preeti Sahu, Giuliano G. Stirparo, Irene M. Aspalter, Alex K. Winkel, Ruby Peters, Henry De Belly, Davide A.D. Cassani, Sarra Achouri     Raphael Blumenfeld, Kristian Franze, Edouard Hannezo, Ewa K. Paluch, Jennifer Nichols and Kevin J. Chalut
Cell surface fluctuations regulate early embryonic lineage sorting
Cell, Volume 185, Issue 5, 3 March 2022, Pages 777-793.e20
DOI: https://doi.org/10.1016/j.cell.2022.01.022

The article “Cell surface fluctuations regulate early embryonic lineage sorting” by Ayaka Yanagida, Elena Corujo-Simon, Christopher K. Revell, Preeti Sahu, Giuliano G. Stirparo, Irene M. Aspalter, Alex K. Winkel, Ruby Peters, Henry De Belly, Davide A.D. Cassani, Sarra Achouri     Raphael Blumenfeld, Kristian Franze, Edouard Hannezo, Ewa K. Paluch, Jennifer Nichols and Kevin J. Chalut is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third-party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/.

Antimicrobial Peptide Mastoparan-AF Kills Multi-Antibiotic Resistant Escherichia coli O157:H7 via Multiple Membrane Disruption Patterns and Likely by Adopting 3–11 Amphipathic Helices to Favor Membrane Interaction

The emergence of multiple antibiotic-resistant bacteria, notably, pan-resistant Gram-negative pathogens, which are equipped with an outer membrane barrier of low permeability to antibiotics, has become an important challenge in recent decades following the overuse of antibiotics in humans and animals. *

In particular, the foodborne enteric pathogen Escherichia coli O157:H7 has caused severe or deadly illness cases worldwide. *

Among E. coli O157 isolates, serotype O157:H7 is the most common enteric pathogen isolated from patients with bloody diarrhea and it is also frequently found in non-bloody diarrhea samples. Many of its clinical isolates from humans and animals as well as isolates from contaminated food have been found to develop resistance to several antibiotics. *

Following the first isolation of mastoparan, the most abundant peptide in the hornet or wasp venom, from Vespula lewisii, many homologs of mastoparan were isolated from various hornets and solitary wasps. *

Mastoparan homologs are cationic tetradecapeptides with membrane permeabilizing activity and antimicrobial activity on various bacteria, mast cell degranulation activity, and hemolytic activity. *

In the article “Antimicrobial Peptide Mastoparan-AF Kills Multi-Antibiotic Resistant Escherichia coli O157:H7 via Multiple Membrane Disruption Patterns and Likely by Adopting 3–11 Amphipathic Helices to Favor Membrane Interaction” Chun-Hsien Lin, Ching-Lin Shyu, Zong-Yen Wu, Chao-Min Wang, Shiow-Her Chiou, Jiann-Yeu Chen, Shu-Ying Tseng, Ting-Er Lin, Yi-Po Yuan, Shu-Peng Ho, Kwong-Chung Tung, Frank Chiahung Mao, Han-Jung Lee and Wu-chun Tu investigate the antimicrobial activity and membrane disruption modes of the antimicrobial peptide mastoparan-AF against hemolytic Escherichia coli O157:H7.*

Based on the physicochemical properties, mastoparan-AF may potentially adopt a 3–11 amphipathic helix-type structure, with five to seven nonpolar or hydrophobic amino acid residues forming the hydrophobic face. E. coli O157:H7 and two diarrheagenic E. coli veterinary clinical isolates, which are highly resistant to multiple antibiotics, are sensitive to mastoparan-AF, with minimum inhibitory and bactericidal concentrations (MIC and MBC) ranging from 16 to 32 μg mL−1 for E. coli O157:H7 and four to eight μg mL−1 for the latter two isolates. *

Mastoparan-AF treatment, which correlates proportionally with membrane permeabilization of the bacteria, may lead to abnormal dents, large perforations or full opening at apical ends (hollow tubes), vesicle budding, and membrane corrugation and invagination forming irregular pits or pores on E. coli O157:H7 surface. In addition, mRNAs of prepromastoparan-AF and prepromastoparan-B share a 5′-poly(A) leader sequence at the 5′-UTR known for the advantage in cap-independent translation. *

This is the first report about the physicochemical adaptation of 3–11 amphipathic helices among mastoparans or antimicrobial peptides. *

Considering that E. coli O157:H7 and clinical isolates are highly resistant to multiple classes of antibiotics, mastoparan-AF, with little or mild effect on animal RBCs, could be an effective and alternative treatment to combat hemolytic E. coli O157:H7 and other pathogenic E. coli.*

The topography of bacteria was measured by a commercial atomic force microscope using NanoWorld Pointprobe® NCSTR AFM probes with a typical resonance frequency of 160 kHz and a typical spring constant of 7.4 N/m, respectively. For image quality, the scan rates of the tip were 0.3–0.6 Hz, with a resolution set of 512 by 256 pixels, and the feedback control parameters were optimized. *

Figure 5 from «Antimicrobial Peptide Mastoparan-AF Kills Multi-Antibiotic Resistant Escherichia coli O157:H7 via Multiple Membrane Disruption Patterns and Likely by Adopting 3–11 Amphipathic Helices to Favor Membrane Interaction» by Chun-Hsien Lin et al.:The topology of mastoparan-AF treated-hemolytic E. coli O157:H7 analyzed by AFM. (A) Two-dimensional (2D) and (B) three-dimensional (3D) images show smooth cell surfaces of untreated hemolytic E. coli O157:H7. (C) A 2D image of mastoparan-AF (32 μg mL−1)-treated hemolytic E. coli O157:H7. Abnormal perforations and dents on the surface of bacteria are indicated by arrows and arrowheads, respectively. The 3D images focusing on two highlighted areas of (C), respectively, reveal (D) a rough cell surface and (E) a hollow tube resulting from perforations at apical ends. (F) A 3D image shows a mastoparan-AF-treated bacterium with a budding vesicle. (G) A 3D image shows mastoparan-AF-treated bacteria with a wrinkled or rough surface. (H) Magnification of portion of (G) displays, in high resolution, the surface roughness of a mastoparan-AF-treated bacterium. The topography of bacteria was measured by a commercial atomic force microscope using NanoWorld Pointprobe® NCSTR AFM probes with a typical resonance frequency of 160 kHz and a typical spring constant of 7.4 N/m, respectively. For image quality, the scan rates of the tip were 0.3–0.6 Hz, with a resolution set of 512 by 256 pixels, and the feedback control parameters were optimized. *
Figure 5 from «Antimicrobial Peptide Mastoparan-AF Kills Multi-Antibiotic Resistant Escherichia coli O157:H7 via Multiple Membrane Disruption Patterns and Likely by Adopting 3–11 Amphipathic Helices to Favor Membrane Interaction» by Chun-Hsien Lin et al.:
The topology of mastoparan-AF treated-hemolytic E. coli O157:H7 analyzed by AFM. (A) Two-dimensional (2D) and (B) three-dimensional (3D) images show smooth cell surfaces of untreated hemolytic E. coli O157:H7. (C) A 2D image of mastoparan-AF (32 μg mL−1)-treated hemolytic E. coli O157:H7. Abnormal perforations and dents on the surface of bacteria are indicated by arrows and arrowheads, respectively. The 3D images focusing on two highlighted areas of (C), respectively, reveal (D) a rough cell surface and (E) a hollow tube resulting from perforations at apical ends. (F) A 3D image shows a mastoparan-AF-treated bacterium with a budding vesicle. (G) A 3D image shows mastoparan-AF-treated bacteria with a wrinkled or rough surface. (H) Magnification of portion of (G) displays, in high resolution, the surface roughness of a mastoparan-AF-treated bacterium.

*Chun-Hsien Lin, Ching-Lin Shyu, Zong-Yen Wu, Chao-Min Wang, Shiow-Her Chiou, Jiann-Yeu Chen, Shu-Ying Tseng, Ting-Er Lin, Yi-Po Yuan, Shu-Peng Ho, Kwong-Chung Tung, Frank Chiahung Mao, Han-Jung Lee and Wu-chun Tu
Antimicrobial Peptide Mastoparan-AF Kills Multi-Antibiotic Resistant Escherichia coli O157:H7 via Multiple Membrane Disruption Patterns and Likely by Adopting 3–11 Amphipathic Helices to Favor Membrane Interaction
Membranes 2023, 13(2), 251
DOI: https://doi.org/10.3390/membranes13020251

The article “Antimicrobial Peptide Mastoparan-AF Kills Multi-Antibiotic Resistant Escherichia coli O157:H7 via Multiple Membrane Disruption Patterns and Likely by Adopting 3–11 Amphipathic Helices to Favor Membrane Interaction” by Chun-Hsien Lin, Ching-Lin Shyu, Zong-Yen Wu, Chao-Min Wang, Shiow-Her Chiou, Jiann-Yeu Chen, Shu-Ying Tseng, Ting-Er Lin, Yi-Po Yuan, Shu-Peng Ho, Kwong-Chung Tung, Frank Chiahung Mao, Han-Jung Lee and Wu-chun Tu is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third-party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/.