Photocatalytic Bactericidal Mechanism of Nanoscale TiO2 Films on Escherichia coli

2011 ◽  
Vol 11 (9) ◽  
pp. 7621-7626 ◽  
Author(s):  
Danmei Pan ◽  
Zhibing Zhan ◽  
Dagui Chen ◽  
Zhicheng Wu ◽  
Aiying Pang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bactericidal Mechanism

scholarly journals Relationship between mechano-bactericidal activity and nanoblades density on chemically strengthened glass

2021 ◽  
Vol 11 (1) ◽  
pp. 138-146
Author(s):  
Yuan Xie ◽  
Yuanhua He ◽  
Xiantao Chen ◽  
Daqin Bu ◽  
Xiaolong He ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bactericidal Activity ◽  
Civil Aviation ◽  
Ultrasonic Cleaning ◽  
Strengthened Glass ◽  
Alkaline Etching ◽  
Bactericidal Mechanism ◽  
Etching Method ◽  
Bactericidal Properties ◽  
New Generation

Abstract Establishing the correlation between the topography and the bactericidal performance is the key to improve the mechano-bactericidal activity. However, due to the complexity of the mechano-bactericidal mechanism, the correlation between density and bactericidal performance is still not clear. Based on this, a series of nanoblades (NBs) with various density but similar thickness and height were prepared on the chemically strengthened glass (CSG) substrate by a simple alkaline etching method. The mechano-bactericidal properties of NBs on CSG (NBs@CSG) surfaces exposed to Escherichia coli were evaluated. The results show that with the NB density increasing, the mechano-bactericidal performance of the surface increased first and then decreased. Besides, the bactericidal performance of NBs@CSG is not affected after four consecutive ultrasonic cleaning bactericidal experiments. This article can provide guidance for the design of the new generation of mechano-bactericidal surfaces. In addition, this technology is expected to be applied to the civil aviation cabin window lining.

scholarly journals Photocatalytic Protein Damage by Silver Nanoparticles Circumvents Bacterial Stress Response and Multidrug Resistance

mSphere ◽  
2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Tianyuan Shi ◽  
Qiuxia Wei ◽  
Zhen Wang ◽  
Gong Zhang ◽  
Xuesong Sun ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Drug Resistance ◽  
Silver Nanoparticles ◽  
Protein Aggregation ◽  
Antibacterial Properties ◽  
Resistance Mechanisms ◽  
Resistant Bacteria ◽  
Bacterial Cells ◽  
Content Type ◽  
Bactericidal Mechanism

ABSTRACT Silver nanoparticles (AgNPs) are known for their broad-spectrum antibacterial properties, especially against antibiotic-resistant bacteria. However, the bactericidal mechanism of AgNPs remains unclear. In this study, we found that the bactericidal ability of AgNPs is induced by light. In contrast to previous postulates, visible light is unable to trigger silver ion release from AgNPs or to promote AgNPs to induce reactive oxygen species (ROS) in Escherichia coli. In fact, we revealed that light excited AgNPs to induce protein aggregation in a concentration-dependent manner in E. coli, indicating that the bactericidal ability of AgNPs relies on the light-catalyzed oxidation of cellular proteins via direct binding to proteins, which was verified by fluorescence spectra. AgNPs likely absorb the light energy and transfer it to the proteins, leading to the oxidation of proteins and thus promoting the death of the bacteria. Isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics revealed that the bacteria failed to develop effective resistance to the light-excited AgNPs. This direct physical mechanism is unlikely to be counteracted by any known drug resistance mechanisms of bacteria and therefore may serve as a last resort against drug resistance. This mechanism also provides a practical hint regarding the antimicrobial application of AgNPs—light exposure improves the efficacy of AgNPs. IMPORTANCE Although silver nanoparticles (AgNPs) are well known for their antibacterial properties, the mechanism by which they kill bacterial cells remains a topic of debate. In this study, we uncovered the bactericidal mechanism of AgNPs, which is induced by light. We tested the efficacy of AgNPs against a panel of antimicrobial-resistant pathogens as well as Escherichia coli under conditions of light and darkness and revealed that light excited the AgNPs to promote protein aggregation within the bacterial cells. Our report makes a significant contribution to the literature because this mechanism bypasses microbial drug resistance mechanisms, thus presenting a viable option for the treatment of multidrug-resistant bacteria.

scholarly journals Antibacterial and Antimembrane Activities of Cecropin A in Escherichia coli

2000 ◽  
Vol 44 (3) ◽  
pp. 602-607 ◽  
Author(s):  
Loraine Silvestro ◽  
Jeffrey N. Weiser ◽  
Paul H. Axelsen
Keyword(s):  
Escherichia Coli ◽  
Bactericidal Activity ◽  
Membrane Permeabilization ◽  
Lipid Vesicle ◽  
Cecropin A ◽  
Vesicle Membranes ◽  
Bactericidal Mechanism ◽  
Concentration Dependences

ABSTRACT The ability of cecropin A to permeabilize and depolarize the membranes of Escherichia coli ML-35p bacteria has been compared to its bactericidal activity in an extension of earlier studies performed on synthetic lipid vesicle membranes (L. Silvestro, K. Gupta, J. H. Weiser, and P. H. Axelsen, Biochemistry 36:11452–11460, 1997). Our results indicate that differences in the concentration dependences of membrane permeabilization and depolarization seen in synthetic vesicles are not manifested in whole bacteria. The concentration dependences of both phenomena roughly correlate with bactericidal activity, suggesting that the bactericidal mechanism of cecropin A is related to membrane permeabilization.

Structural organization of escherichia coli ribosomes as determined by immuno electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 166-167 ◽  
Author(s):  
G. Stöffler ◽  
R.W. Bald ◽  
J. Dieckhoff ◽  
H. Eckhard ◽  
R. Lührmann ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Ribosomal Subunit ◽  
Spatial Arrangement ◽  
Small Subunit ◽  
Antibody Binding ◽  
Immuno Electron Microscopy

A central step towards an understanding of the structure and function of the Escherichia coli ribosome, a large multicomponent assembly, is the elucidation of the spatial arrangement of its 54 proteins and its three rRNA molecules. The structural organization of ribosomal components has been investigated by a number of experimental approaches. Specific antibodies directed against each of the 54 ribosomal proteins of Escherichia coli have been performed to examine antibody-subunit complexes by electron microscopy. The position of the bound antibody, specific for a particular protein, can be determined; it indicates the location of the corresponding protein on the ribosomal surface.The three-dimensional distribution of each of the 21 small subunit proteins on the ribosomal surface has been determined by immuno electron microscopy: the 21 proteins have been found exposed with altogether 43 antibody binding sites. Each one of 12 proteins showed antibody binding at remote positions on the subunit surface, indicating highly extended conformations of the proteins concerned within the 30S ribosomal subunit; the remaining proteins are, however, not necessarily globular in shape (Fig. 1).

Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

1967 ◽  
Vol 25 ◽  
pp. 96-97
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Electron Microscope ◽  
Uranyl Acetate ◽  
E Coli ◽  
Receptor Sites ◽  
Rigid Cell Wall ◽  
Host Cell Surface ◽  
Bacterial Viruses ◽  
Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

Infection of Escherichia coli with bacteriophages

1969 ◽  
Vol 27 ◽  
pp. 370-371
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Nucleic Acid ◽  
Cell Surface ◽  
Virus Type ◽  
Infection Process ◽  
Adsorption Site ◽  
The Other ◽  
Specific Receptors ◽  
Bacterial Receptors

The first step in the infection of a bacterium by a virus consists of a collision between cell and bacteriophage. The presence of virus-specific receptors on the cell surface will trigger a number of events leading eventually to release of the phage nucleic acid. The execution of the various "steps" in the infection process varies from one virus-type to the other, depending on the anatomy of the virus. Small viruses like ØX 174 and MS2 adsorb directly with their capsid to the bacterial receptors, while other phages possess attachment organelles of varying complexity. In bacteriophages T3 (Fig. 1) and T7 the small conical processes of their heads point toward the adsorption site; a welldefined baseplate is attached to the head of P22; heads without baseplates are not infective.

The Nature of the Intramembrane Particle

1980 ◽  
Vol 38 ◽  
pp. 688-691
Author(s):  
A.J. Verkleij
Keyword(s):  
Escherichia Coli ◽  
Tight Junction ◽  
Gap Junction ◽  
The Other ◽  
Fracture Face ◽  
Band 3 Protein ◽  
Satisfactory Explanation ◽  
Freeze Fracturing ◽  
Intramembrane Particle ◽  
Luminal Membrane

Freeze-fracturing splits membranes into two helves, thus allowing an examination of the membrane interior. The 5-10 rm particles visible on both monolayers are widely assumed to be proteinaceous in nature. Most membranes do not reveal impressions complementary to particles on the opposite fracture face, if the membranes are fractured under conditions without etching. Even if it is considered that shadowing, contamination or fracturing itself might obscure complementary pits', there is no satisfactory explanation why under similar physical circimstances matching halves of other membranes can be visualized. A prominent example of uncomplementarity is found in the erythrocyte manbrane. It is wall established that band 3 protein and possibly glycophorin represents these nonccmplanentary particles. On the other hand a number of membrane types show pits opposite the particles. Scme well known examples are the ";gap junction',"; tight junction, the luminal membrane of the bladder epithelial cells and the outer membrane of Escherichia coli.

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