The cell surface of Propionibacterium acnes: effect of specific chemical modifications on the ability of vaccines to produce splenomegaly in mice

1982 ◽  
Vol 28 (4) ◽  
pp. 375-382 ◽  
Author(s):  
Alastair T. Pringle ◽  
Cecil S. Cummins
Keyword(s):  
Cell Surface ◽  
Propionibacterium Acnes ◽  
Reticuloendothelial System ◽  
Chemical Modifications ◽  
Specific Chemical ◽  
Sodium Metaperiodate ◽  
Chemical Treatments ◽  
Strong Acids ◽  
Ionizable Groups ◽  
Phosphate Groups

The surface of Propionibacterium acnes, VPI 0009, was studied using microelectrophoresis following chemical treatments intended to modify specific charged groups. The effect of these specific chemical modifications on ability of cells to induce splenomegaly, an indicator of stimulation of the reticuloendothelial system, was also determined. There was little difference between pH mobility curves of P. acnes VPI 0009 and other strains of propionibacteria which were not able to stimulate the reticuloendothelial system. Amino and carboxyl groups were found to be the sole ionizable groups at the cell surface and modification of these groups caused a substantial decrease in the ability of cells to stimulate the reticuloendothelial system. No phosphate groups were detected. Evidence for two types of amino groups was found: one type was present on protein moieties and their modification did not affect ability to stimulate the reticuloendothelial system, whereas modification of the other type, which was present on carbohydrate moieties, caused a loss of ability to stimulate the reticuloendothelial system. Mild oxidation with sodium metaperiodate caused abolition of reticuloendothelial system stimulation, but had no effect on surface charged groups, indicating it was acting on the unsubstituted linkages of sugar residues. Treatments with strong acids caused abolition of ability to stimulate the reticuloendothelial system and this was accompanied by release of polysaccharide material.

scholarly journals A localized molecular automaton for in situ visualization of proteins with specific chemical modifications

2020 ◽  
Vol 11 (6) ◽  
pp. 1665-1671
Author(s):  
Lu Liu ◽  
Siqiao Li ◽  
Anwen Mao ◽  
Guyu Wang ◽  
Yiran Liu ◽  
...  
Keyword(s):  
Cell Surface ◽  
Specific Protein ◽  
Chemical Modifications ◽  
Specific Chemical ◽  
Propagation Algorithm ◽  
In Situ Visualization

A localized DNA automaton is reported for in situ visualization of a specific protein subtype with dual chemical modifications on the cell surface, which executes protein-confined computation according to an anticoding–coding propagation algorithm.

scholarly journals Non-protein components of the cell surface of Staphylococcus aureus

1968 ◽  
Vol 107 (6) ◽  
pp. 817-821 ◽  
Author(s):  
A. M. James ◽  
J. E. Brewer
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Surface ◽  
Teichoic Acid ◽  
Surface Damage ◽  
Sodium Metaperiodate ◽  
Maximum Value ◽  
Dependent Change ◽  
Ph Dependent ◽  
Pass Through ◽  
Protein Components

1. pH–mobility curves of various laboratory strains of Staphylococcus aureus are non-sigmoid in shape, and all pass through a maximum value in the range pH4–5. 2. The maxima in the curves are not due to incomplete washing of the cells, adsorption of buffer components or irreversible surface damage. 3. Mild oxidation of the cell-surface teichoic acid with sodium metaperiodate gives cells that have typical sigmoid pH–mobility curves, characteristic of either a simple carboxyl surface or a mixed carboxyl–amino surface. 4. The results are discussed in terms of a pH-dependent change in the configuration of the teichoic acid molecules at the surface.

scholarly journals Analysis of Cr(III) ions adsorption on the surface of algae: implications for the removal of heavy metal ions from water

2021 ◽  
Vol 4 (10(112)) ◽  
pp. 14-23
Author(s):  
Zhadra Tattibayeva ◽  
Sagdat Tazhibayeva ◽  
Wojciech Kujawski ◽  
Bolatkhan Zayadan ◽  
Kuanyshbek Мusabekov ◽  
...  
Keyword(s):  
Cell Surface ◽  
Metal Ions ◽  
Functional Groups ◽  
Ζ Potential ◽  
Adsorption Data ◽  
Abnormal Increase ◽  
Ph Range ◽  
Langmuir And Freundlich Models ◽  
Phosphate Groups ◽  
Comprehensive Study

For purposeful control of the adsorption process, a comprehensive study of the properties of the original cells and the effect of metal ions on them is necessary. In this regard, the features of the adsorption of Cr(III) ions on the cell surface of Spirulina platensis algae were studied. FTIR spectroscopy revealed that the main functional groups responsible for the binding of Cr(III) ions are carboxyl, hydroxyl, amino, and phosphate groups on the surface of algae. The adsorption data were processed using the Langmuir and Freundlich models. It is shown that the maximum adsorption of Cr(III) ions on the surface of algae cells is 31.25 mg/g. The Freundlich constant 1/n is 0.65. The study of the effect of the concentration of Cr(III) ions on the Zeta-potential of algae cells revealed an abnormal increase in the negative value of the ζ – potential at 10–5 mol/L, caused by the release of an additional amount of anionic functional groups to the surface. A further increase in the concentration of Cr(III) ions in the algae suspension leads to a decrease in the ζ – potential and recharge of the surface at C>10–2 mol/L. It was found that the adsorption of Cr(III) ions also affects the morphology of the cell surface. If before contact with Cr(III) ions, the surface of algae cells is represented as a uniform green grid, after adsorption of Cr(III) ions, the surface becomes green-brown, with swollen spirals. The study of the effect of pH on the adsorption and desorption processes shows an increase in the desorption of Cr(III) ions from the surface of algae during acidification of the medium. The adsorption reaches a maximum value in the pH range of 6–7. In the region of optimal Cr(III)/biosorbent ion ratios, the recovery rate of Cr(III) reaches 98.5–99.3 %.

scholarly journals Hydrogen-ion titration studies on erythrocyte membranes

1976 ◽  
Vol 156 (1) ◽  
pp. 159-165 ◽  
Author(s):  
C Hallam ◽  
J M Wrigglesworth
Keyword(s):  
Membrane Structure ◽  
Plasma Membranes ◽  
Sodium Dodecyl ◽  
Spectrophotometric Assay ◽  
Hydrogen Ion ◽  
Erythrocyte Membranes ◽  
Chemical Treatments ◽  
Before And After ◽  
Selective Chemical ◽  
Ionizable Groups

1. H+ titration was used to detect the presence of ionizable groups on human erythrocyte plasma membranes. Between pH2.9 and 11.3, two significant peaks of H+ association/dissociation occur in the differential from of the titration curve, one at pH3. 1. And the other at pH10.3. 2. After disruption of membrane structure by exposure to high pH or by the addition of sodium dodecyl sulphate, maxima of H+ association/dissociation were seen at pH3.1,4.3,6.5,10.3 and 10.7. 3. Spectrophotometric assay and selective chemical treatments were used to identify several of the titratable residues. 4. The degree of eleectrostatic interaction between titratable charged groups was investigated by comparing the titration characteristics of the membranes before and after modification of membrane structure.

scholarly journals Production of a toxic polypeptide as a fusion inside GroEL cavity

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Maria S. Yurkova ◽  
Elchin G. Sadykhov ◽  
Alexey N. Fedorov
Keyword(s):  
Polypeptide Chain ◽  
Scale Up ◽  
Antibacterial Peptides ◽  
Specific Chemical ◽  
Chemical Treatments ◽  
Total Replacement ◽  
Host Cell Proteins ◽  
Binding Surface ◽  
One Step ◽  
Methionine Residues

AbstractThe system is developed for efficient biosynthetic production of difficult-to-express polypeptides. A target polypeptide is produced fused into T. thermophilus GroEL chaperonin polypeptide chain in such a way that it is presented inside the GroEL cavity near the substrate binding surface. Such presentation allows alleviating potential problems of instability, toxicity or hydrophobicity of the fused peptide. Thermostability of thermophilic GroEL can be used for its one-step separation from the host cell proteins by heating. The target polypeptide may be released by any of amino acid-specific chemical treatments. In this study, GroEL was adapted for methionine-specific cleavage with cyanogen bromide by total replacement of methionine residues to facilitate further purification of the target polypeptide. The procedure is simple, robust and easy to scale-up. The capacity of this system to produce difficult-to-express polypeptides is demonstrated by production in bacterial system of one of the most potent antibacterial peptides polyphemusin I.

Chemical Modifications of Escherichia coli Ribosomal Proteins S4, S7, and S8 in Regard to Their Capacity for Binding 16 S RNA

1974 ◽  
Vol 52 (11) ◽  
pp. 1038-1043 ◽  
Author(s):  
Gérald Lemieux
Keyword(s):  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Binding Capacity ◽  
Cysteine Residue ◽  
Amino Groups ◽  
Chemical Modifications ◽  
Specific Chemical ◽  
Rna Interaction ◽  
Rna Complex ◽  
Rna Complexes

Mild specific chemical modifications were used to test the possible role of cysteines, tyrosines, and amino groups of ribosomal proteins S4, S7, and S8 for binding to 16 S RNA (Escherichia coli). The single cysteine residue present in proteins S4 and S8 is not directly involved in the binding process with RNA. The protein S7 does not contain cysteine. Total nitration of tyrosines in S4, S7, and S8 abolishes the binding capacity of these proteins. However, when the modification is done with the preformed protein–RNA complexes, some protection occurs. Two amino groups could be reacted in free S8 as well as in an S8–RNA complex. This modification does not influence protein–RNA interaction. Proteins S4, S7, and S8 in Regard to Their Capacity for Binding 16 S RNA. Can. J. Biochem. 52, modified. A new method for the stoichiometric determination of single protein–RNA complexes is presented.

scholarly journals Isolation and partial characterization of antibody- and globin-enriched complexes from membranes of dense human erythrocytes

1991 ◽  
Vol 278 (1) ◽  
pp. 57-62 ◽  
Author(s):  
R Kannan ◽  
J Yuan ◽  
P S Low
Keyword(s):  
Membrane Protein ◽  
Cell Surface ◽  
Integral Membrane Protein ◽  
Protein Band ◽  
Reticuloendothelial System ◽  
Band 3 ◽  
Isolation And Characterization ◽  
Protein Clusters ◽  
Associated Proteins

In previous studies we have described a process whereby an erythrocyte in biochemical distress can initiate its own removal by macrophages of the reticuloendothelial system. This process involves the clustering of the integral membrane protein band 3 by denatured haemoglobin and the subsequent recognition of the exofacial poles of clustered band 3 and associated proteins by autologous antibodies. To determine whether this clearance pathway might mediate normal cell turnover, the fraction of normal erythrocytes containing the 0.5% densest cells, which are known to be destined for immediate removal, was isolated and characterized biochemically. This densest fraction was found to contain 6 times more membrane-bound globin (haemichromes) and 10 times more surface-bound autologous IgG than the other fractions containing cells of lower density. To determine whether the autologous IgG was physically associated with the haemichrome-stabilized membrane protein clusters, a procedure was developed for isolation and characterization of the microscopic aggregates. The isolated aggregates were found to contain a disulphide-cross-linked mixture of several membrane proteins, predominantly haemichromes, spectrin and band 3. Although the aggregates constituted only 0.09% of the total membrane protein, they still contained approximately 55% of the total cell-surface IgG. Since in control studies anti-(blood group A) antibodies, which are distributed randomly over the surface of type A cells, could not be recovered in the aggregate, we conclude that the autologous cell-surface IgGs were physically associated with the membrane protein clusters when they were co-isolated with them in our procedure. Thus the 640-fold enrichment of autologous IgG in the aggregates compared with regions of the membrane devoid of tightly clustered protein suggests that sites of integral protein clustering either are non-specifically sticky to IgG or are viewed as foreign or ‘non-self’ by the immune system and aggressively opsonized with IgG.

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