Determining Mechanical Properties of Escherichia Coli by Nanoindentation

2012 ◽  
Vol 1424 ◽  
Author(s):  
C. A. Wright ◽  
C.J. Sullivan ◽  
B. Crawford ◽  
L.D. Britt ◽  
M.A. Mamun ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Mechanical Properties ◽  
Cell Wall ◽  
Contact Area ◽  
Solute Concentration ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
A Cell ◽  
Afm Cantilever

ABSTRACTEscherichia coli, like other gram-negative bacteria, is protected from the surrounding harsh environment by a cell wall consisting of the peptidoglycan and outer membrane. Whereas the cytoplasmic membrane is the selective barrier, the cell wall provides mechanical strength for the cell. As bacteria navigate various environments, osmotic pressure can change dramatically due to changes in local solute concentration. The peptidoglycan together with the cellular proteins mitigates the osmotic stress that would otherwise cause lysis. The mechanical properties of E. coli cells and its individual layers have been largely indeterminable until the recent development of probe-based measurement tools. Since their invention, scientists have reported significant data measuring elasticity, modulus, and stiffness using atomic force microscopy (AFM). Fundamentally, in order to determine these mechanical properties through probe-based techniques, the contact area and load should be well defined. The load can be precisely calculated through the AFM cantilever spring constant. However, the silicon tip contact area can only be estimated, potentially leading to compounding uncertainties. Therefore, we developed a methodology to determine nanomechanical properties of E. coli using a nanoindenter.

scholarly journals Variation of Burkholderia cenocepacia cell wall morphology and mechanical properties during cystic fibrosis lung infection, assessed by atomic force microscopy

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
A. Amir Hassan ◽  
Miguel V. Vitorino ◽  
Tiago Robalo ◽  
Mário S. Rodrigues ◽  
Isabel Sá-Correia
Keyword(s):  
Mechanical Properties ◽  
Cystic Fibrosis ◽  
Atomic Force Microscopy ◽  
Cell Wall ◽  
Adaptive Evolution ◽  
Burkholderia Cenocepacia ◽  
Force Microscopy ◽  
Atomic Force ◽  
Morphology And Mechanical Properties

Abstract The influence that Burkholderia cenocepacia adaptive evolution during long-term infection in cystic fibrosis (CF) patients has on cell wall morphology and mechanical properties is poorly understood despite their crucial role in cell physiology, persistent infection and pathogenesis. Cell wall morphology and physical properties of three B. cenocepacia isolates collected from a CF patient over a period of 3.5 years were compared using atomic force microscopy (AFM). These serial clonal variants include the first isolate retrieved from the patient and two late isolates obtained after three years of infection and before the patient’s death with cepacia syndrome. A consistent and progressive decrease of cell height and a cell shape evolution during infection, from the typical rods to morphology closer to cocci, were observed. The images of cells grown in biofilms showed an identical cell size reduction pattern. Additionally, the apparent elasticity modulus significantly decreases from the early isolate to the last clonal variant retrieved from the patient but the intermediary highly antibiotic resistant clonal isolate showed the highest elasticity values. Concerning the adhesion of bacteria surface to the AFM tip, the first isolate was found to adhere better than the late isolates whose lipopolysaccharide (LPS) structure loss the O-antigen (OAg) during CF infection. The OAg is known to influence Gram-negative bacteria adhesion and be an important factor in B. cenocepacia adaptation to chronic infection. Results reinforce the concept of the occurrence of phenotypic heterogeneity and adaptive evolution, also at the level of cell size, form, envelope topography and physical properties during long-term infection.

Comparative Study of AFM and FESEM for Imaging the Single Cell of Escherichia Coli Bacteria

2015 ◽  
Vol 34 ◽  
pp. 61-66
Author(s):  
Kamarulazizi Ibrahim ◽  
Mohammad Hafiz Khalid ◽  
Mohamed Hassan Eisa ◽  
Mohd Nazalan Najimudin ◽  
Mohammad A. Al Rajhi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Comparative Study ◽  
Single Cell ◽  
Food Poisoning ◽  
Rapid Identification ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Identification Of Bacteria ◽  
Escherichia Coli Bacteria

In this work, a comparative study using atomic force microscopy (AFM) and field emission–scanning electron microscopy (FESEM) has been carried out to assess the morphology of single cellEscherichia colibacteria (E-coli).E-colibacteria are a major concern for public health. Attention was focused on the certain strains ofE-colibacteria, because some strains can be toxic and cause food poisoning. TheE-colibacteria have attracted much research interest because this bacterium is easily to get, cheap and rapid reproductively. Imaging ofE-colirecently, was improved by using high resolution microscopy. Current techniques for detection such as, AFM and FESEM has attracted great interest and emerging as a potentially powerful whole-organism fingerprinting tool for the rapid identification of bacteria. The obtained results of AFM and FESEM techniques have been compared to show the image quality of single cellE-coli.

scholarly journals Atomic Force Microscopy Study of the Effect of Antimicrobial Peptides on the Cell Envelope of Escherichia coli

2005 ◽  
Vol 49 (10) ◽  
pp. 4085-4092 ◽  
Author(s):  
M. Meincken ◽  
D. L. Holroyd ◽  
M. Rautenbach
Keyword(s):  
Escherichia Coli ◽  
Atomic Force Microscopy ◽  
Morphological Changes ◽  
Cell Envelope ◽  
Microscopy Study ◽  
Target Cells ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Before And After

ABSTRACT The influences of the antibacterial magainin 2 and PGLa from the African clawed frog (Xenopus laevis) and the hemolytic bee venom melittin on Escherichia coli as the target cell were studied by atomic force microscopy (AFM). Nanometer-scale images of the effects of the peptides on this gram-negative bacterium's cell envelope were obtained in situ without the use of fixing agents. These high-resolution AFM images of the surviving and intact target cells before and after peptide treatment showed distinct changes in cell envelope morphology as a consequence of peptide action. Although all three peptides are lytic to E. coli, it is clear from this AFM study that each peptide causes distinct morphological changes in the outer membrane and in some cases the inner membrane, probably as a consequence of different mechanisms of action.

Motion of a Cell Wall Polysaccharide Observed by Atomic Force Microscopy

2000 ◽  
Vol 33 (15) ◽  
pp. 5680-5685 ◽  
Author(s):  
A. Patrick Gunning ◽  
Alan R. Mackie ◽  
Andrew R. Kirby ◽  
Paul Kroon ◽  
Gary Williamson ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Cell Wall ◽  
Cell Wall Polysaccharide ◽  
Force Microscopy ◽  
Atomic Force ◽  
A Cell

scholarly journals A cell wall-associated gene network shapes leaf boundary domains

2021 ◽  
Author(s):  
Nathalie Bouré ◽  
Alexis Peaucelle ◽  
Magali Goussot ◽  
Bernard Adroher ◽  
Ludivine Soubigou-Taconnat ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Growth ◽  
Gene Network ◽  
Force Microscopy ◽  
Atomic Force ◽  
Wall Stiffness ◽  
A Cell ◽  
Wall Loosening ◽  
Building Plant ◽  
Molecular Framework

Boundary domains delimit and organize organ growth throughout plant development almost relentlessly building plant architecture and morphogenesis. Boundary domains display reduced growth and orchestrate development of adjacent tissues in a non-cell autonomous manner. How these two functions are achieved remains elusive despite the identification of several boundary-specific genes. Here, we show using morphometrics at the organ and cellular levels that leaf boundary domain development requires SPINDLY (SPY), an O-fucosyltransferase, to act as cell growth repressor. Further we show that SPY acts redundantly with the CUP-SHAPED COTYLEDON transcription factors (CUC2 and CUC3), which are major determinants of boundaries development. Accordingly at the molecular level, CUC2 and SPY repress a common set of genes involved in cell wall loosening providing a molecular framework for the growth repression associated with boundary domains. Atomic force microscopy (AFM) confirmed that young leaf boundary domain cells have stiffer cell walls than marginal outgrowth. This differential cell wall stiffness was reduced in spy mutant. Taken together our data reveal a concealed CUC2 cell wall associated gene network linking tissue patterning with cell growth and mechanics.

Micromechanical Properties of Spruce Tissues Using Static Nanoindentation and Modulus Mapping

2015 ◽  
Vol 732 ◽  
pp. 115-118
Author(s):  
Zdeněk Prošek ◽  
Jaroslav Topič ◽  
Pavel Tesárek ◽  
Kateřina Indrová ◽  
Václav Nežerka ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Physical And Mechanical Properties ◽  
Mapping Technique ◽  
Force Microscopy ◽  
Micromechanical Properties ◽  
Atomic Force ◽  
Combination Of Methods ◽  
Dynamic Nanoindentation

This paper discusses characterization of physical and mechanical properties of tissues of Norway spruce. Cell wall is composed of several layers, which is, due to their small size, difficult to characterize. For this reason, the work uses a combination of methods, atomic force microscopy (AFM) and nanoindentation. AFM is used to determine the topography of samples and nanoindentation to determine micromechanical properties of wood tissues. Prepared samples of glue laminated timber were tested by quasi-static and dynamic nanoindentation (modulus mapping technique) method.

scholarly journals Bridged filaments of histone-like nucleoid structuring protein pause RNA polymerase and aid termination in bacteria

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Matthew V Kotlajich ◽  
Daniel R Hron ◽  
Beth A Boudreau ◽  
Zhiqiang Sun ◽  
Yuri L Lyubchenko ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Dna Supercoiling ◽  
Direct Effects ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Transcriptional Pausing ◽  
Noncoding Transcription ◽  
Stimulation Of

Bacterial H-NS forms nucleoprotein filaments that spread on DNA and bridge distant DNA sites. H-NS filaments co-localize with sites of Rho-dependent termination in Escherichia coli, but their direct effects on transcriptional pausing and termination are untested. In this study, we report that bridged H-NS filaments strongly increase pausing by E. coli RNA polymerase at a subset of pause sites with high potential for backtracking. Bridged but not linear H-NS filaments promoted Rho-dependent termination by increasing pause dwell times and the kinetic window for Rho action. By observing single H-NS filaments and elongating RNA polymerase molecules using atomic force microscopy, we established that bridged filaments surround paused complexes. Our results favor a model in which H-NS-constrained changes in DNA supercoiling driven by transcription promote pausing at backtracking-susceptible sites. Our findings provide a mechanistic rationale for H-NS stimulation of Rho-dependent termination in horizontally transferred genes and during pervasive antisense and noncoding transcription in bacteria.

scholarly journals Humidity-Dependent Bacterial Cells Functional Morphometry Investigations Using Atomic Force Microscope

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Hike Nikiyan ◽  
Alexey Vasilchenko ◽  
Dmitry Deryabin
Keyword(s):  
Cell Wall ◽  
Relative Humidity ◽  
Morphological Properties ◽  
Wall Structure ◽  
Bacterial Cells ◽  
Wall Roughness ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Wide Range

The effect of a relative humidity (RH) in a range of 93–65% on morphological and elastic properties ofBacillus cereusandEscherichia colicells was evaluated using atomic force microscopy. It is shown that gradual dehumidification of bacteria environment has no significant effect on cell dimensional features and considerably decreases them only at 65% RH. The increasing of the bacteria cell wall roughness and elasticity occurs at the same time. Observed changes indicate that morphological properties ofB. cereusare rather stable in wide range of relative humidity, whereasE. coliare more sensitive to drying, significantly increasing roughness and stiffness parameters at RH 84% RH. It is discussed the dependence of the response features on differences in cell wall structure of gram-positive and gram-negative bacterial cells.

scholarly journals Atomic Force Microscopy Stiffness Tomography on Living Arabidopsis thaliana Cells Reveals the Mechanical Properties of Surface and Deep Cell-Wall Layers during Growth

2012 ◽  
Vol 103 (3) ◽  
pp. 386-394 ◽  
Author(s):  
Ksenija Radotić ◽  
Charles Roduit ◽  
Jasna Simonović ◽  
Patricia Hornitschek ◽  
Christian Fankhauser ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals The Mechanical Properties of E. coli Type 1 Pili Measured by Atomic Force Microscopy Techniques

2006 ◽  
Vol 91 (10) ◽  
pp. 3848-3856 ◽  
Author(s):  
Eric Miller ◽  
Tzintzuni Garcia ◽  
Scott Hultgren ◽  
Andres F. Oberhauser
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Type 1 Pili ◽  
Microscopy Techniques
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