scholarly journals Sham, Sam, And Bacterial Communication

1997 ◽  
Vol 5 (8) ◽  
pp. 8-9
Author(s):  
Lee van Hook

A scanning acoustic microscope (SAM) - a nanomicrophone using a piezoelectric crystal, may be used to examine bacterial colonies, not just materials specimens to detect phonons and listen to propagating microfractures.Since bacterial cell walls are rigid structures, they undergo mechanical distortions when channels open and dose. This causes them to squeak and pop, each channel having its own sound. Channels and receptor molecules are all of different sizes and shapes, and therefore deform the cell wall in unique ways. This means that each channel makes a unique (if faint) sound when it passes a molecule through itself and this activity can be delected, Transport rates of uptake and excretion for the various compounds car then be calculated trom the intensity of the sounds.

1969 ◽  
Vol 47 (1) ◽  
pp. 71-74 ◽  
Author(s):  
Carolyn L. Marshall ◽  
A. J. Wicken ◽  
A. D. Brown

The outer layer of the cell envelope of Halobacterium halobium was isolated after suspending the envelope in either 1 M NaCl or 0.02 M MgCl2. Chemical analysis of the isolated, solubilized outer layer showed it to consist of protein or glycoprotein with about 3% RNA. No free or bound lipid was detected. No cytochromes were present in the outer layer. Components commonly associated with bacterial cell walls were absent.Chemical composition together with the marked instability of the outer layer in a slight ion deficit are not consistent with a function of this layer as a "cell wall" of the organism.


2000 ◽  
Vol 68 (6) ◽  
pp. 3535-3540 ◽  
Author(s):  
Egle Šimelyte ◽  
Marja Rimpiläinen ◽  
Leena Lehtonen ◽  
Xiang Zhang ◽  
Paavo Toivanen

ABSTRACT To study what determines the arthritogenicity of bacterial cell walls, cell wall-induced arthritis in the rat was applied, using four strains of Lactobacillus. Three of the strains used proved to induce chronic arthritis in the rat; all were Lactobacillus casei. The cell wall of Lactobacillus fermentum did not induce chronic arthritis. All arthritogenic bacterial cell walls had the same peptidoglycan structure, whereas that of L. fermentum was different. Likewise, all arthritogenic cell walls were resistant to lysozyme degradation, whereas the L. fermentum cell wall was lysozyme sensitive. Muramic acid was observed in the liver, spleen, and lymph nodes in considerably larger amounts after injection of an arthritogenicL. casei cell wall than following injection of a nonarthritogenic L. fermentum cell wall. The L. casei cell wall also persisted in the tissues longer than theL. fermentum cell wall. The present results, taken together with those published previously, underline the possibility that the chemical structure of peptidoglycan is important in determining the arthritogenicity of the bacterial cell wall.


2009 ◽  
Vol 75 (12) ◽  
pp. 3891-3895 ◽  
Author(s):  
Jia Li ◽  
Xiaomin Hu ◽  
Jianpin Yan ◽  
Zhiming Yuan

ABSTRACT The binding affinities and specificities of six truncated S-layer homology domain (SLH) polypeptides of mosquitocidal Bacillus sphaericus strain C3-41 with the purified cell wall sacculi have been assayed. The results indicated that the SLH polypeptide comprised of amino acids 31 to 210 was responsible for anchoring the S-layer subunits to the rigid cell wall layer via a distinct type of secondary cell wall polymer and that a motif of the recombinant SLH polypeptide comprising amino acids 152 to 210 (rSLH152-210) was essential for the stable binding of the S-layer with the bacterial cell walls. The quantitative assays revealed that the KD (equilibrium dissociation constant) values of rSLH152-210 and rSLH31-210 with purified cell wall sacculi were 1.11 × 10−6 M and 1.40 × 10−6 M, respectively. The qualitative assays demonstrated that the SLH domain of strain C3-41 could bind only to the cell walls or the cells treated with 5 M guanidinium hydrochloride of both toxic and nontoxic B. sphaericus strains but not to those from other bacteria, indicating the species-specific binding of the SLH polypeptide of B. sphaericus with bacterial cell walls.


1967 ◽  
Vol 167 (1009) ◽  
pp. 446-447 ◽  

Although we have heard a lot about the mode of binding of low molecular weight, soluble, lysozyme substrates, we have heard little about the mode of action of lysozyme on its natural insoluble substrate, the bacterial cell wall; so I want to bring a biological flavour into this discussion. Lysozyme was the name given by Fleming (1922) to the powerful bacteriolytic agent found in various cells and secretions; it was particularly active against a new bacterial species which he named Micrococcus lysodeikticus . The walls of this species still provide us with one of the best substrates for the study of lysozyme action. Salton showed that there is a considerable spectrum of activity of lysozyme in solubilizing walls of other species of bacteria. For example, walls of M. lysodeikticus are attacked rapidly by a concentration of enzyme of 1 μg/ml., Bacillus megaterium walls need 50 μg/ml., while walls of B. cereus are hardly changed visibly by 50 μg/ml. Consideration of the structure of the basal mucopeptide unit of bacterial cell walls, illustrated by Dr Perkins, shows that there are many ways in which structural differences could be introduced. Knowledge of the effects of some of these differences on lysozyme sensitivity may help in elucidating the mode of action of lysozyme on the complete bacterial cell wall.


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