scholarly journals Variations in the Morphology, Mechanics and Adhesion of Persister and Resister E. coli Cells in Response to Ampicillin: AFM Study

Antibiotics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 235 ◽  
Author(s):  
Samuel C. Uzoechi ◽  
Nehal I. Abu-Lail
Keyword(s):  
Surface Area ◽  
Bacterial Cells ◽  
Persister Cells ◽  
Bacterial Surface ◽  
E Coli ◽  
Surface Areas ◽  
Atomic Force ◽  
Grafting Density ◽  
New Antibiotics ◽  
Surface Biopolymers

Persister bacterial cells are great at surviving antibiotics. The phenotypic means by which they do that are underexplored. As such, atomic force microscope (AFM) was used to quantify the contributions of the surface properties of the outer membrane of multidrug resistance (MDR)-Escherichia coli Strains (A5 and A9) in the presence of ampicillin at minimum inhibitory concentration (MIC) (resistant cells) and at 20× MIC (persistent cells). The properties quantified were morphology, root mean square (RMS) roughness, adhesion, elasticity, and bacterial surface biopolymers’ thickness and grafting density. Compared to untreated cells, persister cells of E. coli A5 increased their RMS, adhesion, apparent grafting density, and elasticity by 1.2, 3.4, 2.0, and 3.3 folds, respectively, and decreased their surface area and brush thickness by 1.3 and 1.2 folds, respectively. Similarly, compared to untreated cells, persister cells of E. coli A9 increased their RMS, adhesion and elasticity by 1.6, 4.4, and 4.5 folds, respectively; decreased their surface area and brush thickness by 1.4 and 1.6 folds, respectively; and did not change their grafting densities. Our results indicate that resistant and persistent E. coli A5 cells battled ampicillin by decreasing their size and going through dormancy. The resistant E. coli A9 cells resisted ampicillin through elongation, increased surface area, and adhesion. In contrast, the persistent E. coli A9 cells resisted ampicillin through increased roughness, increased surface biopolymers’ grafting densities, increased cellular elasticities, and decreased surface areas. Mechanistic insights into how the resistant and persistent E. coli cells respond to ampicillin’s treatment are instrumental to guide design efforts exploring the development of new antibiotics or renovating the existing antibiotics that may kill persistent bacteria by combining more than one mechanism of action.

scholarly journals Comparison of Escherichia coli surface attachment methods for single-cell microscopy

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yao-Kuan Wang ◽  
Ekaterina Krasnopeeva ◽  
Ssu-Yuan Lin ◽  
Fan Bai ◽  
Teuta Pilizota ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Single Cell ◽  
Super Resolution ◽  
Bacterial Cells ◽  
Surface Attachment ◽  
Bacterial Physiology ◽  
E Coli ◽  
Single Cell Imaging ◽  
Atomic Force

AbstractFor in vivo, single-cell imaging bacterial cells are commonly immobilised via physical confinement or surface attachment. Different surface attachment methods have been used both for atomic force and optical microscopy (including super resolution), and some have been reported to affect bacterial physiology. However, a systematic comparison of the effects these attachment methods have on the bacterial physiology is lacking. Here we present such a comparison for bacterium Escherichia coli, and assess the growth rate, size and intracellular pH of cells growing attached to different, commonly used, surfaces. We demonstrate that E. coli grow at the same rate, length and internal pH on all the tested surfaces when in the same growth medium. The result suggests that tested attachment methods can be used interchangeably when studying E. coli physiology.

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 Persister cells mediate tolerance to metal oxyanions in Escherichia coli

Microbiology ◽  
2005 ◽  
Vol 151 (10) ◽  
pp. 3181-3195 ◽  
Author(s):  
Joe J. Harrison ◽  
Howard Ceri ◽  
Nicole J. Roper ◽  
Erin A. Badry ◽  
Kimberley M. Sproule ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Viable Cell ◽  
Small Population ◽  
Water Soluble ◽  
Bacterial Cells ◽  
Persister Cells ◽  
Term Survival ◽  
E Coli ◽  
Cell Counts ◽  
High Concentrations

Bacterial cultures produce subpopulations of cells termed ‘persisters’, reputedly known for high tolerance to killing by antibiotics. Ecologically, antibiotics produced by competing microflora are only one potential stress encountered by bacteria. Another pressure in the environment is toxic metals that are distributed ubiquitously by human pollution, volcanic activity and the weathering of minerals. This study evaluated the time- and concentration-dependent killing of Escherichia coli planktonic and biofilm cultures by the water-soluble metal(loid) oxyanions chromate (), arsenate (), arsenite (), selenite (), tellurate () and tellurite (). Correlative to previous reports in the literature, control antibiotic assays indicated that a small proportion of E. coli biofilm populations remained recalcitrant to killing by antibiotics (even with 24 h exposure). In contrast, metal oxyanions presented a slow, bactericidal action that eradicated biofilms. When exposed for 2 h, biofilms were up to 310 times more tolerant to killing by metal oxyanions than corresponding planktonic cultures. However, by 24 h, planktonic cells and biofilms were eradicated at approximately the same concentration in all instances. Coloured complexes of metals and chelators could not be generated in biofilms exposed to or , suggesting that the extracellular polymeric matrix of E. coli may have a low binding affinity for metal oxyanions. Viable cell counts at 2 and 24 h exposure revealed that, at high concentrations, all of the metal oxyanions had killed 99 % (or a greater proportion) of the bacterial cells in biofilm populations. It is suggested here that the short-term survival of <1 % of the bacterial population corresponds well with the hypothesis that a small population of persister cells may be responsible for the time-dependent tolerance of E. coli biofilms to high concentrations of metal oxyanions.

Atomic Force Microscopy Studies of the Interaction of Antimicrobial Peptides with Bacterial Cells

2017 ◽  
Vol 70 (2) ◽  
pp. 130 ◽  
Author(s):  
Anna Mularski ◽  
Frances Separovic
Keyword(s):  
Atomic Force Microscopy ◽  
Antimicrobial Peptides ◽  
Turgor Pressure ◽  
Living Cells ◽  
Bacterial Cells ◽  
Diverse Range ◽  
Bacterial Surface ◽  
Force Microscopy ◽  
Atomic Force ◽  
Conventional Antibiotics

Antimicrobial peptides (AMPs) are promising therapeutic alternatives to conventional antibiotics. Many AMPs are membrane-active but their mode of action in killing bacteria or in inhibiting their growth remains elusive. Recent studies indicate the mechanism of action depends on peptide structure and lipid components of the bacterial cell membrane. Owing to the complexity of working with living cells, most of these studies have been conducted with synthetic membrane systems, which neglect the possible role of bacterial surface structures in these interactions. In recent years, atomic force microscopy has been utilized to study a diverse range of biological systems under non-destructive, physiologically relevant conditions that yield in situ biophysical measurements of living cells. This approach has been applied to the study of AMP interaction with bacterial cells, generating data that describe how the peptides modulate various biophysical behaviours of individual bacteria, including the turgor pressure, cell wall elasticity, bacterial capsule thickness, and organization of bacterial adhesins.

scholarly journals Persister Cells Resuscitate via Ribosome Modification by 23S rRNA Pseudouridine Synthase RluD

2019 ◽  
Author(s):  
Sooyeon Song ◽  
Thomas K. Wood
Keyword(s):  
Escherichia Coli ◽  
Small Rna ◽  
23S Rrna ◽  
Bacterial Cells ◽  
Persister Cells ◽  
E Coli ◽  
Pseudouridine Synthase ◽  
Dormant Cells ◽  
Wide Range ◽  
Persister Cell

ABSTRACTUpon a wide range of stress conditions (e.g., nutrient, antibiotic, oxidative), a subpopulation of bacterial cells known as persisters survive by halting metabolism. These cells resuscitate rapidly to reconstitute infections once the stress is removed and nutrients are provided. However, how these dormant cells resuscitate is not understood well but involves reactivating ribosomes. By screening 10,000 compounds directly for stimulating Escherichia coli persister cell resuscitation, we identified that 2-{[2-(4-bromophenyl)-2-oxoethyl]thio}-3-ethyl-5,6,7,8-tetrahydro[1]benzothieno[2,3-d]pyrimidin-4(3H)-one (BPOET) stimulates resuscitation. Critically, by screening 4,267 E. coli proteins, we determined that BPOET activates hibernating ribosomes via 23S rRNA pseudouridine synthase RluD, which increases ribosome activity. Corroborating the increased waking with RluD, production of RluD increased the number of active ribosomes in persister cells. Also, inactivating the small RNA RybB which represses rluD led to faster persister resuscitation. Hence, persister cells resuscitate via activation of RluD.

scholarly journals Imaging live bacteria at the nanoscale: comparison of immobilisation strategies

2019 ◽  
Author(s):  
Georgina Benn ◽  
Alice L. B. Pyne ◽  
Maxim G. Ryadnov ◽  
Bart W Hoogenboom
Keyword(s):  
Cell Envelope ◽  
Bacterial Cells ◽  
Label Free ◽  
Bacterial Surface ◽  
Force Microscopy ◽  
Correlative Imaging ◽  
Atomic Force ◽  
Live Bacteria ◽  
Surface Functionalisation ◽  
Bacterial Adsorption

AbstractAtomic force microscopy (AFM) provides an effective, label-free technique enabling the imaging of live bacteria under physiological conditions with nanometre precision. However, AFM is a surface scanning technique, and the accuracy of its performance requires the effective and reliable immobilisation of bacterial cells onto substrates. Here, we compare the effectiveness of various chemical approaches to facilitate the immobilisation of Escherichia coli onto glass cover slips in terms of bacterial adsorption, viability and compatibility with correlative imaging by fluorescence microscopy. We assess surface functionalisation using gelatin, poly-L-lysine, Cell-Tak™, and Vectabond®. We describe how bacterial immobilisation, viability and suitability for AFM experiments depend on bacterial strain, buffer conditions and surface functionalisation. We demonstrate the use of such immobilisation by AFM images that resolve the porin lattice on the bacterial surface; local degradation of the bacterial cell envelope by an antimicrobial peptide (Cecropin B); and the formation of membrane attack complexes on the bacterial membrane.

scholarly journals Gene Amplification Uncovers Large Previously Unrecognized Cryptic Antibiotic Resistance Potential in E. coli

2021 ◽  
Author(s):  
Stacy A. Suarez ◽  
Adam C. Martiny
Keyword(s):  
Antibiotic Resistance ◽  
Gene Amplification ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Bacterial Cells ◽  
Adaptive Resistance ◽  
E Coli ◽  
New Antibiotics

Predicting where new antibiotic resistance genes will rise is a challenge and is especially important when new antibiotics are developed. Adaptive resistance allows sensitive bacterial cells to become transiently resistant to antibiotics.

scholarly journals Proteome dynamics in persisting and resuscitating bacterial cells

2020 ◽  
Author(s):  
Maja Semanjski ◽  
Fabio Gratani ◽  
Till Englert ◽  
Viktor Beke ◽  
Nicolas Nalpas ◽  
...  
Keyword(s):  
Abc Transporters ◽  
Treatment Time ◽  
Bacterial Cells ◽  
Persister Cells ◽  
Time Resolved ◽  
E Coli ◽  
Associated Proteins ◽  
Label Incorporation ◽  
Insight Into

AbstractBacterial persister cells become transiently tolerant to antibiotics by restraining their growth and metabolic activity. Detailed molecular characterization of bacterial persistence is hindered by low count of persisting cells and the need for their isolation. Here we used sustained addition of stable isotope-labeled lysine to selectively label the proteome of hipA-induced persisting and hipB-induced resuscitating E. coli cells in minimal medium after antibiotic treatment. Time-resolved, 24-hour measurement of label incorporation allowed detection of over 500 newly synthetized proteins in persister cells, demonstrating low but widespread protein synthesis. Many essential proteins were newly synthesized and several ribosome-associated proteins showed unusually high synthesis levels, pointing to their roles in maintenance of persistence. At the onset of resuscitation, cells synthesized ABC transporters, restored translation machinery and resumed metabolism by inducing glycolysis and biosynthesis of amino acids. This dataset provides an unprecedented insight into the processes governing persistence and resuscitation of bacterial cells.

scholarly journals Nano- and Macroscale Imaging of Cholesterol Linoleate and Human Beta Defensin 2-Induced Changes in Pseudomonas aeruginosa Biofilms

Antibiotics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1279
Author(s):  
Brent A. Beadell ◽  
Andy Chieng ◽  
Kevin R. Parducho ◽  
Zhipeng Dai ◽  
Sam On Ho ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Cells ◽  
Biofilm Inhibition ◽  
Bacterial Surface ◽  
Force Microscopy ◽  
Novel Treatments ◽  
Atomic Force ◽  
Biofilm Production ◽  
Extracellular Structures ◽  
Induced Changes

The biofilm production of Pseudomonas aeruginosa (PA) is central to establishing chronic infection in the airways in cystic fibrosis. Epithelial cells secrete an array of innate immune factors, including antimicrobial proteins and lipids, such as human beta defensin 2 (HBD2) and cholesteryl lineolate (CL), respectively, to combat colonization by pathogens. We have recently shown that HBD2 inhibits biofilm production by PA, possibly linked to interference with the transport of biofilm precursors. Considering that both HBD2 and CL are increased in airway fluids during infection, we hypothesized that CL synergizes with HBD2 in biofilm inhibition. CL was formulated in phospholipid-based liposomes (CL-PL). As measured by atomic force microscopy of single bacteria, CL-PL alone and in combination with HBD2 significantly increased bacterial surface roughness. Additionally, extracellular structures emanated from untreated bacterial cells, but not from cells treated with CL-PL and HBD2 alone and in combination. Crystal violet staining of the biofilm revealed that CL-PL combined with HBD2 effected a significant decrease of biofilm mass and increased the number of larger biofilm particles consistent with altered cohesion of formed biofilms. These data suggest that CL and HBD2 affect PA biofilm formation at the single cell and community-wide level and that the community-wide effects of CL are enhanced by HBD2. This research may inform future novel treatments for recalcitrant infections in the airways of CF patients.

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