Partial repression of siderophore-mediated iron transport in Azotobacter vinelandii grown with mineral iron

1988 ◽  
Vol 34 (5) ◽  
pp. 675-679 ◽  
Author(s):  
William J. Page ◽  
Gregory A. Grant
Keyword(s):  
Molecular Weight ◽  
Outer Membrane ◽  
Iron Transport ◽  
Mineral Content ◽  
Azotobacter Vinelandii ◽  
Outer Membrane Proteins ◽  
Additional Component ◽  
Transport Activity ◽  
Fe Uptake ◽  
Mineral Concentrations

Azotobacter vinelandii grown in iron-limited medium containing increased amounts of the minerals olivine or glauconite produced decreased amounts of siderophores and iron-repressible outer membrane proteins. These minerals caused a relatively rapid repression of the pyoverdin-type siderophore, azotobactin, and a slower repression of the catechol siderophores, azotochelin and aminochelin. A 77 000 molecular weight outer membrane protein also was repressed with increased mineral content of the medium, but coordinate repression with any one siderophore was not evident. Cells grown with increased mineral concentrations progressively lost siderophore-mediated iron-transport activity. This loss in activity had the greatest effect on azotobactin-mediated 55Fe uptake, but catechol siderophore mediated 55Fe uptake also was depressed. These results suggested that an additional component was required for maximal iron-transport activity promoted by all the siderophores of A. vinelandii.

Variability of Low-Molecular-Weight, Heat-Modifiable Outer Membrane Proteins of Neisseria meningitidis

1980 ◽  
Vol 30 (3) ◽  
pp. 642-648
Author(s):  
J. T. Poolman ◽  
S. De Marie ◽  
H. C. Zanen
Keyword(s):  
Molecular Weight ◽  
Outer Membrane ◽  
High Molecular Weight ◽  
Outer Membrane Proteins ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Low Molecular Weight ◽  
Molecular Weights ◽  
Sds Page ◽  
Index Cases

Analysis of major outer membrane protein (MOMP) profiles of various meningococci by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (SDS-PAGE) revealed the presence of 0 to 2 low-molecular-weight, heat-modifiable MOMPs (molecular weight, 25,000 to 32,000) and 1 to 3 high-molecular-weight MOMPs (molecular weight, 32,000 to 46,000). Heat modifiability was investigated by comparing MOMP profiles after heating in SDS solutions at 100°C for 5 min or at 40°C for 1 h. Low-molecular-weight MOMPs shifted to higher apparent molecular weights after being heated at 100°C. Heat modifiability of high-molecular-weight MOMPs varied among strains; whenever modified these proteins shifted to lower apparent molecular weights after complete denaturation. Variability of low-molecular-weight, heat-modifiable MOMPs was demonstrated when MOMP profiles were compared of (i) isolates from index cases and associated cases and carriers among contacts, (ii) different isolates from the same individual, and (iii) isolates from a small epidemic caused by serogroup W-135. In some cases high-molecular-weight MOMPs revealed quantitative differences among related strains. The observed variability and quantitative differences indicate that MOMP serotyping and typing on the basis of SDS-PAGE profiles (PAGE typing) need careful reevaluation.

P1 bacteriophage and tellurite sensitivity in Klebsiella pneumoniae and Escherichia coli

1984 ◽  
Vol 30 (6) ◽  
pp. 830-836 ◽  
Author(s):  
Juan Tomás ◽  
Miguel Regué ◽  
Ramón Parés ◽  
Juan Jofre ◽  
William W. Kay
Keyword(s):  
Escherichia Coli ◽  
Molecular Weight ◽  
Klebsiella Pneumoniae ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Protein S ◽  
The Other ◽  
E Coli ◽  
P1 Receptor ◽  
Spontaneous Mutants

Klebsiella pneumoniae and Escherichia coli respond inversely toward P1 bacteriophage or [Formula: see text]. Klebsiella pneumoniae is resistant to both antagonists and E. coli is sensitive. However, P1 cmts lysogens (P1 cmts resistant) of K. pneumoniae became sensitive to tellurite and when cured from P1 cmts regained resistance. Escherichia coli spontaneous mutants selected for resistance to either P1 or [Formula: see text] were collaterally resistant to the other. As well, [Formula: see text] enhanced the adsorption of P1 vir to both E. coli and K. pneumoniae. Several outer membrane proteins were enhanced in the K. pneumoniae lysogens and were reduced in E. coli lysogens; one of which was the same molecular weight (77 000) in both bacteria. When partially purified it enhanced the plaque efficiency of P1 vir. Lipopolysaccharide (LPS) from E. coli C600 inactivated P1 vir, but neither the P1 lysogens nor LPS derived from the lysogens inactivated P1 vir. Escherichia coli P1 lysogens produced only heptose-deficient LPS. It is suggested that both LPS and outer membrane protein(s) comprise the P1 receptor. [Formula: see text] may interact with one or both components.

Determination of Low Molecular weight Immunogenic Omp28 Protein and Gene of Salmonella typhimurium

2019 ◽  
Vol 8 (5) ◽  
pp. 172-177
Author(s):  
Rajeev Kumar ◽  
S. P. Singh ◽  
Mahesh Kumar ◽  
Anil Kumar
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Outer Membrane ◽  
Close Agreement ◽  
Outer Membrane Proteins ◽  
Low Molecular Weight ◽  
Predicted Amino Acid Sequence ◽  
Calculated Molecular Weight ◽  
Amplicon Size

Outer membrane of Gram-negative bacteria has complex profile of proteins. The outer membrane proteins (OMPs) isolated from S. typhimurium by urea-EDTA extraction method and analysed through SDS-PAGE showed a complex electrophoretic profile having more than 15 low molecular weight proteins with molecular masses ranging between 3.5 and 43 kDa. The most important outer membrane protein (Omp28) of S. typhimurium with submolecular masses of 12.32kDa of main protein was recovered. The gene responsible for expression of this protein was also amplified through PCR and sequenced, showed 341bp amplicon size and predicted amino acid sequence of this pro-tein was determined. The Antigenic index was calculated from amino acid sequence of same gene and found 2.2 (0.1-2.2) suggesting highly antigenic in nature. The experimentally determined values are close agreement with the theoretically calculated molecular weight 12.32 kDa and pI: 9.61 from the gene sequence of this protein. The antigenic natures of predicted protein values are close agreement with experimental determent of Omp28 of S. typhimurium a possible formula for vaccine developmental of genus Salmonella.

Resolution of Basic Gonococcal Outer Membrane Proteins by Nonequilibrium pH Gradient Electrophoresis

1980 ◽  
Vol 30 (3) ◽  
pp. 773-780
Author(s):  
Robert B. Jones ◽  
Patricia A. Jemison ◽  
Wilbert J. Newhall ◽  
Richard A. Haak
Keyword(s):  
Molecular Weight ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Isoelectric Focusing ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Sodium Dodecyl ◽  
Ph Gradient ◽  
Gradient Electrophoresis

Outer membrane proteins from opaque and transparent colonial variants of strain F62 of Neisseria gonorrhoeae were analyzed by two-dimensional electrophoresis with isoelectric focusing in the first dimension and sodium dodecyl sulphate-polyacrylamide gel electrophoresis in the second. Most of the higher-molecular-weight proteins focused sharply in the acidic region of the gel. In contrast, the principal outer membrane protein, a 31,000-molecular-weight protein, and the opacity-associated proteins remained near the origin (at the basic end of the gel) without focusing. However, when the samples were loaded on the acidic end of an isoelectric focusing gel and subjected to nonequilibrium pH gradient electrophoresis, these proteins behaved as basic proteins. In addition, three distinct opacity-associated heat-modifiable proteins could be identified. No other differences in the protein composition of outer membranes from opaque and transparent variants were apparent. Amino acid analysis of the principal outer membrane protein indicated that its net positive charge may result from partial amidation of its acidic residues. The unexpected observation that the major surface proteins of the gonococcus are basic may have implications for intragonococcal adhesion and for gonococcal interactions with mammalian cells.

scholarly journals Cross-linking analysis of the outer membrane proteins of Neisseria gonorrhoeae

1980 ◽  
Vol 28 (3) ◽  
pp. 785-791 ◽  
Author(s):  
W J Newhall ◽  
W D Sawyer ◽  
R A Haak
Keyword(s):  
Molecular Weight ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Neisseria Gonorrhoeae ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Polyacrylamide Gel Electrophoresis ◽  
Cross Linking ◽  
Protein Aggregate

The organization of outer membrane proteins of Neisseria gonorrhoeae was investigated by using two-dimensional dodecyl sulfate-polyacrylamide gel electrophoresis and cross-linking agents. A naturally occurring protein aggregate, which may be composed of two proteins of 50,000 molecular weight, was detected in all strains. Treatment of whole cells with cross-linking agents yielded several additional complexes, suggesting that other proteins are arranged in the outer membrane as near neighbors. The principal outer membrane protein (molecular weight, 34,000) cross-linked (i) to itself to form a complex whch appeared to be trimeric, (ii) to the 28,000-molecular-weight outer membrane protein to form a bimolecular comlex, and (iii) to the 28,000-molecular-weight outer membrane protein in a 3:1 ratio. The formation of these complexes was independent of (i) colony type, (ii) colony opacity, (iii) pH during growth, and (iv) presence of markers for drug resistance or hypersensitivity.

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