scholarly journals Microcin E492, a low-molecular-weight peptide antibiotic which causes depolarization of the Escherichia coli cytoplasmic membrane.

1985 ◽  
Vol 27 (4) ◽  
pp. 666-669 ◽  
Author(s):  
V de Lorenzo ◽  
A P Pugsley
Keyword(s):  
Escherichia Coli ◽  
Molecular Weight ◽  
Cytoplasmic Membrane ◽  
Low Molecular Weight ◽  
Peptide Antibiotic

Interference with Murein Turnover Has No Effect on Growth but Reduces β-Lactamase Induction in Escherichia coli

1999 ◽  
Vol 181 (23) ◽  
pp. 7192-7198 ◽  
Author(s):  
Angelika R. Kraft ◽  
Julia Prabhu ◽  
Astrid Ursinus ◽  
Joachim-Volker Höltje
Keyword(s):  
Escherichia Coli ◽  
Molecular Weight ◽  
Enterobacter Cloacae ◽  
Low Molecular Weight ◽  
Specific Inhibition ◽  
Triple Mutant ◽  
Induced Expression ◽  
Lytic Transglycosylases ◽  
Reduced Rate ◽  
Specific Inhibitors

ABSTRACT Physiological studies of a mutant of Escherichia colilacking the three lytic transglycosylases Slt70, MltA, and MltB revealed that interference with murein turnover can prevent AmpC β-lactamase induction. The triple mutant, although growing normally, shows a dramatically reduced rate of murein turnover. Despite the reduction in the formation of low-molecular-weight murein turnover products, neither the rate of murein synthesis nor the amount of murein per cell was increased. This might be explained by assuming that during growth in the absence of the major lytic transglycosylases native murein strands are excised by the action of endopeptidases and directly reused without further breakdown to muropeptides. The reduced rate of murein turnover could be correlated with lowered cefoxitin-induced expression of β-lactamase, present on a plasmid carrying theampC and ampR genes from Enterobacter cloacae. Overproduction of MltB stimulated β-lactamase induction, whereas specific inhibition of Slt70 by bulgecin repressedampC expression. Thus, specific inhibitors of lytic transglycosylases can increase the potency of penicillins and cephalosporins against bacteria inducing AmpC-like β-lactamases.

Monoclonal antibodies against the capsular K antigen of Escherichia coli (09: K30(A): H12): characterisation and use in analysis of K antigen organisation on the cell surface

1988 ◽  
Vol 34 (10) ◽  
pp. 1159-1165 ◽  
Author(s):  
Mary K. Homonylo ◽  
Sheila J. Wilmot ◽  
Joseph S. Lam ◽  
Leslie A. MacDonald ◽  
Christopher Whitfield
Keyword(s):  
Escherichia Coli ◽  
Molecular Weight ◽  
Monoclonal Antibodies ◽  
Cell Surface ◽  
Molecular Probes ◽  
Low Molecular Weight ◽  
Gel Chromatography ◽  
E Coli ◽  
Capsular Antigen ◽  
K Antigen

Monoclonal antibodies were produced against the capsular antigen of Escherichia coli serotype K(A)30, using a mouse hybridoma system. The antibodies also recognised the chemically identical capsular polysaccharide produced by Klebsiella K20. Chemical modification of the K30 polysaccharide indicated that the glucuronic acid residues found in the E. coli K30 capsular antigen were important in the epitope recognised by these antibodies. Use of the antibodies as molecular probes revealed the presence of two discrete forms of the K30 antigen. One form was comprised of high molecular weight polysaccharide, present as a surface capsular layer. The second form of the antigen was of low molecular weight and was associated with lipopolysaccharide fractions from cell surface polysaccharide extracts. Separation of lipopolysaccharide fractions using gel chromatography in the presence of detergent showed that the low molecular weight K-antigenic fraction comigrated with a lipopolysaccharide lipid A core fraction present in encapsulated E. coli K30 bacteria but absent in acapsular mutants.

Bactericidal action of peptide antibiotic AS-48 against Escherichia coli K-12

1989 ◽  
Vol 35 (2) ◽  
pp. 318-321 ◽  
Author(s):  
A. Gálvez ◽  
E. Valdivia ◽  
M. Martínez ◽  
M. Maqueda
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Cell Growth ◽  
Mode Of Action ◽  
Cytoplasmic Membrane ◽  
Peptide Antibiotic ◽  
Biosynthetic Pathways ◽  
Bactericidal Action ◽  
Cell Wall Synthesis ◽  
K 12

Peptide antibiotic AS-48 exerts a bactericidal mode of action on exponential cultures of Escherichia coli K-12 through a multi-hit kinetics interaction. AS-48 causes a parallel and gradual cessation of all biosynthetic pathways monitored (protein, RNA, DNA, and cell wall synthesis), the rate of incorporation of labeled precursors, the rate of O2 consumption, and cell growth. These effects have been attributed to alterations of cytoplasmic membrane functions.Key words: Escherichia coli, peptide antibiotic, bactericide.

scholarly journals Non-Invasive Physical Plasma Enhances the Membrane Permeability to Low Molecular Weight Compounds and Subsequently Leads to the Loss of Cellular ATP and the Devitalization of Epithelial Cancer Cells

2021 ◽  
Vol 11 (21) ◽  
pp. 9801
Author(s):  
Caroline Sander ◽  
Andreas Nitsch ◽  
Holger H. H. Erb ◽  
Eva K. Egger ◽  
Lyubomir Haralambiev ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Molecular Weight ◽  
Cancer Cells ◽  
Cytoplasmic Membrane ◽  
Reactive Oxygen ◽  
Cell Physiology ◽  
Low Molecular Weight ◽  
Non Invasive ◽  
Low Molecular Weight Compounds ◽  
Physical Plasma

Non-invasive physical plasma (NIPP) achieves biomedical effects primarily through the formation of reactive oxygen and nitrogen species. In clinical use, these species interact with cells of the treated tissue, affecting the cytoplasmic membrane first. The present study investigated the permeability of the cytoplasmic membrane of breast cancer cells with different fluorescent dyes after NIPP treatment and determined the subsequent effects on cell viability. After NIPP treatment and the associated formation of reactive oxygen species, low molecular weight compounds were able to pass through the cytoplasmic membrane in both directions to a higher extent. Consequently, a loss of cellular ATP into the extracellular space was induced. Due to these limitations in cell physiology, apoptosis was induced in the cancer cells and the entire cell population exhibited decreased cell growth. It can be concluded that NIPP treatment disturbs the biochemical functionality of the cytoplasmic membrane of cancer cells, which massively impairs their viability. This observation opens a vast application horizon of NIPP therapy to treat precancerous and malignant diseases beyond breast cancer therapy.

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