scholarly journals Scanning ion conductance microscopy reveals differences in the ionic environments of gram positive and negative bacteria

2020 ◽  
Author(s):  
Kelsey Cremin ◽  
Bryn Jones ◽  
James Teahan ◽  
Gabriel N. Meloni ◽  
David Perry ◽  
...  
Keyword(s):  
Cell Wall ◽  
Surface Charge ◽  
Wall Structure ◽  
Current Response ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Fem Model ◽  
Ion Conductance ◽  
E Coli ◽  
Scanning Ion Conductance Microscopy

AbstractThis paper reports on the use of scanning ion conductance microscopy (SICM) to locally map the ionic properties and charge environment of two live bacterial strains: the gramnegative Escherichia coli and the gram-positive Bacillus subtilis. SICM results find heterogeneities across the bacterial surface, and significant differences among the grampositive and -negative bacteria. The bioelectrical environment of the B. subtilis was found to be considerably more negatively charged compared to E. coli. SICM measurements, fitted to a simplified finite element method (FEM) model, revealed surface charge values of −80 to −140 mC m−2 for the gram-negative E. coli. The gram-positive B. subtilis show a much higher conductivity around the cell wall, and surface charge values between −350 and −450 mC m−2 were found using the same simplified model. SICM was also able to detect regions of high negative charge near B. subtilis, not detected in the topographical SICM response and attributed to extracellular polymeric substance. To further explore how the B. subtilis cell wall structure can influence the SICM current response, a more comprehensive FEM model, accounting for the physical properties of the gram-positive cell wall, was developed. The new model provides a more realistic description of the cell wall and allowed investigation of the relation between its key properties and SICM currents, building foundations to further investigate and improve understanding of the gram-positive cellular microenvironment.Abstract Figure

Die gemeinsame Wurzel der Lyse von Escherichia coli durch Penicillin oder durch Phagen

1957 ◽  
Vol 12 (7) ◽  
pp. 421-427 ◽  
Author(s):  
W. Weidel ◽  
J. Primosigh
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Building Blocks ◽  
Diaminopimelic Acid ◽  
Wall Structure ◽  
Gram Positive ◽  
E Coli ◽  
Growing Cell ◽  
Cell Wall Disruption ◽  
Entire Cell

One of the two layers of the E. coli B cell wall is shown to possess the chemical composition typical of a gram-positive microorganism. It is this layer which lends support and strength to the entire cell wall structure, its rigidity depending up on the incorporation of building blocks made up from alanine, glutamic acid, diaminopimelic acid, muramic acid and glucosamine.Phage enzyme is an agent capable of removing these stabilizing units from the „gram-positive “ layer, thereby causing it to collapse. Penicillin appears to prevent the biosynthetic incorporation of the same stabilizing units into growing cell walls, thus producing eventually the effect of cell wall disruption in a basically similar way.The rather manifold aspects of these findings are discussed at some length.

scholarly journals Mapping Surface Charge of Individual Microdomains with Scanning Ion Conductance Microscopy

2018 ◽  
Vol 5 (20) ◽  
pp. 2986-2990 ◽  
Author(s):  
Cheng Zhu ◽  
Lushan Zhou ◽  
Myunghoon Choi ◽  
Lane A. Baker
Keyword(s):  
Surface Charge ◽  
Ion Conductance ◽  
Scanning Ion Conductance Microscopy

Gauging surface charge distribution of live cell membrane by ionic current change using scanning ion conductance microscopy

Nanoscale ◽  
2021 ◽  
Author(s):  
Feng Chen ◽  
Jin He ◽  
Prakash Manandhar ◽  
Yizi Yang ◽  
Peidang Liu ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Surface Charge ◽  
Charge Distribution ◽  
Ionic Current ◽  
Live Cells ◽  
Ion Conductance ◽  
Physiological Conditions ◽  
Scanning Ion Conductance Microscopy ◽  
Surface Charge Distribution ◽  
Current Change

The distribution of surface charge and potential of cell membrane plays an indispensable role in cellular activities. However, probing surface charge of live cells in physiological conditions, until recently, remains...

scholarly journals Antibacterial Activity of Tannic Acid and Tannic Acid/Amphiphilic Cationic Polymer Mixtures

2020 ◽  
Vol 32 (6) ◽  
pp. 1491-1496
Author(s):  
Fatimah M. Alzahrani ◽  
Stephen G. Yeates ◽  
Michelle Webb ◽  
Hind Ali Alghamdi
Keyword(s):  
Antibacterial Activity ◽  
Tannic Acid ◽  
Cationic Polymer ◽  
Polymer Mixture ◽  
Klebsiella Pneumonia ◽  
Cationic Polymers ◽  
Polymer Mixtures ◽  
Bacterial Strains ◽  
Gram Positive ◽  
E Coli

In this study, the antibacterial activity of tannic acid/amphiphilic cationic polymer (poly{2-[(methacryloyloxy)ethyl]trimethyl-ammonium chloride}, PMADQUAT) and tannic acid mixtures was examined on the strains of Gram-positive (S. aureus) and Gram-negative (E. coli CI2, E. coli K12, Klebsiella pneumonia and P. aeruginosa) bacteria. Tannic acid exhibited the antibacterial activity against all the studied bacterial strains. The ester linkage between glucose and gallic acid is vital for the antimicrobial activity of tannic acid. Tannic acid inhibited the growth of S. aureus and E. coli K12 (1 wt%) and reduced the growth of P. aeruginosa to 23%. Mixing cationic polymers having different structures (statistical copolymer, homopolymer and diblock polymer) with tannic acid lead to an increase in antibacterial activity of tannic acid and the stability and clarity of mixtures was higher than that of a pure tannic acid solution. Tannic acid/diblock polymer and tannic acid/homopolymer mixtures (0.1 wt%) were excellent for inhibiting the growth of planktonic E. coli K12 bacteria, and a low concentration (0.0001 wt%) of tannic acid/diblock polymer reduced its growth to 19%. By contrast, the tannic acid/statistical polymer mixture (0.0001 wt%) was excellent for inhibiting the growth of Gram-positive S. aureus bacteria.

Evolution of Our Experience in Diagnosis and Therapy for Urinary Infections

2009 ◽  
Vol 76 (2) ◽  
pp. 140-143
Author(s):  
R. Pizzorno ◽  
A. Simonato ◽  
M. Esposito ◽  
T. Montanaro ◽  
M. Mussap ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Empirical Therapy ◽  
Enterococcus Species ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Diagnosis And Therapy ◽  
Urinary Infections ◽  
Spectrum Activity

The therapy for urinary infections is advised according to the antibiogram; the symptoms request an empirical therapy based on urinary infections knowledge and drugs spectrum activity. We considered the urinoculture performed on 3834 patients, 3012 male and 822 female, hospitalized in our Institute in the period between 01/01/2005 and 31/10/2006; 444 of these were positive (12.7 % - 451 bacterial strains). Table 1: bacterial strains isolaed. We reported some evaluations obtained by antibiogram. E. coli strains Ciprofloxacin sensitive resulted in 60% of cases. Enterococcus species and Enterococcus faecalis strains Ampicillin sensitive resulted in 96.4% and 100% of cases, respectively. In this study there is a Gram negative prevalence, whereas we had previously observed an equivalence between Gram negative and Gram positive (p 0.001). These data are useful for empirical therapy.

scholarly journals Spectral Studies and Antibacterial Activity of Vanadium(III) Complexes of Heterocyclic Hydrazones

2020 ◽  
Vol 32 (5) ◽  
pp. 1059-1063
Author(s):  
D. Kasimbi ◽  
K. Hussain Reddy ◽  
N. Devanna
Keyword(s):  
Analytical Techniques ◽  
Spectral Studies ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Tridentate Ligands ◽  
Structure Comparison ◽  
Gram Negative ◽  
E Coli ◽  
Physico Chemical ◽  
Uv Visible

Vanadium(III) complexes having the composition VLCl3 [where L = 2-acetylpyridine acetoylhydrazone (APAH), 2-acetylpyridine benzoylhydrazone (APBH), 2-acetylthiophene acetoylhydrazone (ATAH) and 2-acetylthiophene benzoylhydrazone (ATBH)] have been investigated using physico-chemical and analytical techniques. Molar conductivity data suggested that the complexes are neutral. Structures of all the vanadium(III) complexes are determined based on infrared and UV-visible spectral data. Electronic spectra of vanadium(III) complexes show three peaks suggesting octahedral structure. Comparison of vibrational spectra of hydrazones and complexes suggest that the hydrazones act as neutral tridentate ligands. The ligands and their vanadium derivatives are screened for their bacteria destroying activity against pathogenic bacterial strains viz. Gram-negative E. coli, Gram-positive Bacillus, Gram-positive Staphylococcus aureus and Gram-negative P. aureoginosa. Bacteria destroying activities of present complexes are comparable to the activity of the streptomycin. Complexes show more activity than their respective ligands in the case of Gram-positive Bacillus and Gram-negative P. aureoginosa.

scholarly journals Interactions between Penicillin-Binding Proteins (PBPs) and Two Novel Classes of PBP Inhibitors, Arylalkylidene Rhodanines and Arylalkylidene Iminothiazolidin-4-ones

2004 ◽  
Vol 48 (3) ◽  
pp. 961-969 ◽  
Author(s):  
Astrid Zervosen ◽  
Wei-Ping Lu ◽  
Zhouliang Chen ◽  
Ronald E. White ◽  
Thomas P. Demuth ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Cell Wall Synthesis ◽  
Bacterial Strains ◽  
Gram Negative ◽  
Penicillin Binding Proteins ◽  
E Coli ◽  
Peptidoglycan Biosynthesis ◽  
Vancomycin Resistant ◽  
Inhibitory Activities

ABSTRACT Several non-β-lactam compounds were active against various gram-positive and gram-negative bacterial strains. The MICs of arylalkylidene rhodanines and arylalkylidene iminothiazolidin-4-ones were lower than those of ampicillin and cefotaxime for methicillin-resistant Staphylococcus aureus MI339 and vancomycin-resistant Enterococcus faecium EF12. Several compounds were found to inhibit the cell wall synthesis of S. aureus and the last two steps of peptidoglycan biosynthesis catalyzed by ether-treated cells of Escherichia coli or cell wall membrane preparations of Bacillus megaterium. The effects of the arylalkylidene rhodanines and arylalkylidene iminothiazolidin-4-one derivatives on E. coli PBP 3 and PBP 5, Streptococcus pneumoniae PBP 2xS (PBP 2x from a penicillin-sensitive strain) and PBP 2xR (PBP 2x from a penicillin-resistant strain), low-affinity PBP 2a of S. aureus, and the Actinomadura sp. strain R39 and Streptomyces sp. strain R61 dd-peptidases were studied. Some of the compounds exhibited inhibitory activities in the 10 to 100 μM concentration range. The inhibition of PBP 2xS by several of them appeared to be noncompetitive. The dissociation constant for the best inhibitor (Ki = 10 μM) was not influenced by the presence of the substrate.

scholarly journals Fast Nanoscale Surface Charge Mapping with Pulsed-Potential Scanning Ion Conductance Microscopy

2016 ◽  
Vol 88 (22) ◽  
pp. 10854-10859 ◽  
Author(s):  
Ashley Page ◽  
David Perry ◽  
Philip Young ◽  
Daniel Mitchell ◽  
Bruno G. Frenguelli ◽  
...  
Keyword(s):  
Surface Charge ◽  
Ion Conductance ◽  
Scanning Ion Conductance Microscopy

scholarly journals Synthesis and Antimicrobial Evaluations of Sulfur Inserted Fluoro-Benzimidazoles

2021 ◽  
Vol 33 (7) ◽  
pp. 1525-1529
Author(s):  
Parmesh Kumar Dwivedi ◽  
Devdutt Chaturvedi
Keyword(s):  
Antimicrobial Agents ◽  
Bacterial Strains ◽  
Substituted Anilines ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
New Compounds ◽  
Derivatives Of ◽  
Multiple Step

A new series of fluorinated sulfur inserted benzimidazole analogues Za-i were synthesized and characterized. The new compounds were screened for their antimicrobial and antioxidant potential. The synthesized compounds were obtained by multiple step synthesis, initiating from the synthesis of 5-(difluoromethoxy)-1H-benzimidazole-2-thiol X. The compounds Ya-i prepared by reacting differently substituted anilines with chloroacetylchloride and triethylamine in DMF. Finally, the compound X was reacted with different derivatives of 2-chloro-N-phenylacetamide resulting in formation of titled compounds Za-i. The synthesized compounds (Za-Zi) were characterized by spectral analysis viz.1H & 13C NMR, mass spectra, elemental analysis and IR. The in vitro antimicrobial potential against Gram-positive (S. aureus and E. faecalis) and Gram-negative bacterial (E. coli and P.aeruginosa) strains as well as fungi (A. niger and C. albicans) was recorded for the obtained compounds. Some of the compounds exhibited encouraging results (in MIC) against Gram-positive and Gram-negative bacterial strains. These studies thus suggest that the designed sulfur inserted fluoro-benzimidazoles scaffold may serve as new promising template for further amplification as antimicrobial agents.

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