Iron-regulated outer membrane proteins and non-siderophore-mediated iron acquisition by Paracoccus denitrificans

1988 ◽  
Vol 51 (1) ◽  
pp. 33-36
Author(s):  
S Sechan Wee
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Paracoccus Denitrificans ◽  
Iron Acquisition ◽  
Outer Membrane Proteins

Growth characteristics and expression of iron-regulated outer-membrane proteins of chemostat-grown biofilm cells of Pseudomonas aeruginosa

1991 ◽  
Vol 37 (10) ◽  
pp. 737-743 ◽  
Author(s):  
H. Anwar ◽  
J. L. Strap ◽  
J. W. Costerton
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Membrane Proteins ◽  
Dilution Rate ◽  
Outer Membrane ◽  
Iron Uptake ◽  
Iron Acquisition ◽  
Outer Membrane Proteins ◽  
Uptake System ◽  
Planktonic Cells

An in vitro chemostat system was used to study the growth and the expression of iron-regulated outer-membrane proteins (IROMPs) by biofilm cells of Pseudomonas aeruginosa cultivated under conditions of iron limitation. The population of the planktonic cells decreased when the dilution rate was increased. At a dilution rate of 0.05 h−1 the populations of planktonic cells of both mucoid and nonmucoid P. aeruginosa were 3 × 109 cells/mL. This value dropped to 5 × 106 cells/mL when the dilution rate was increased to 1.0 h−1. The reverse was observed for the biofilm cells. The number of biofilm cells colonising the silicone tubing increased when the dilution rate was increased. The number of biofilm cells of the mucoid strain at steady state was 2 × 108 cells/cm (length) when the dilution rate was fixed at 0.05 h−1. The figure increased to 8 × 109 cells/cm when the dilution rate was increased to 1.0 h−1. The population of biofilm cells of the nonmucoid strain was 9 × 107 cells/cm (length) when the dilution rate was 0.05 h−1. It increased to 2 × 109 cells/cm when the dilution rate was set at 1.0 h−1. The expression of IROMPs was induced in the biofilm cells of both mucoid and nonmucoid strains when the dilution rates were 0.05 and 0.2 h−1. IROMPs were reduced but still detectable at the dilution rate of 0.5 h−1. However, the expression of IROMPs was repressed when the dilution rate was increased to 1.0 h−1. The data suggest that the biofilm cells of P. aeruginosa switch on the expression of IROMPs to assist iron acquisition when the dilution rate used for the chemostat run is below 0.5 h−1. The high affinity iron uptake system is not required by the biofilm cells when the dilution rate is increased because the trace amount of iron present in the chemostat is sufficient for the growth of adherent biofilm cells. Key words: Pseudomonas aeruginosa, chemostat, iron, outer-membrane proteins, biofilm.

scholarly journals Iron-regulated outer membrane proteins and non-siderophore-mediated iron acquisition byParacoccus denitrificans

1988 ◽  
Vol 51 (1) ◽  
pp. 33-36 ◽  
Author(s):  
Sechan Wee ◽  
Sharon Hardesty ◽  
Murty V.V.S. Madiraju ◽  
Brian J. Wilkinson
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Iron Acquisition ◽  
Outer Membrane Proteins

scholarly journals The Conservation of Low Complexity Regions in Bacterial Proteins Depends on the Pathogenicity of the Strain and Subcellular Location of the Protein

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 451
Author(s):  
Pablo Mier ◽  
Miguel A. Andrade-Navarro
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Bacterial Species ◽  
Outer Membrane Proteins ◽  
Subcellular Location ◽  
Low Complexity ◽  
Extracellular Proteins ◽  
Bacterial Strains ◽  
Bacterial Proteins ◽  
Protein Subcellular Location

Low complexity regions (LCRs) in proteins are characterized by amino acid frequencies that differ from the average. These regions evolve faster and tend to be less conserved between homologs than globular domains. They are not common in bacteria, as compared to their prevalence in eukaryotes. Studying their conservation could help provide hypotheses about their function. To obtain the appropriate evolutionary focus for this rapidly evolving feature, here we study the conservation of LCRs in bacterial strains and compare their high variability to the closeness of the strains. For this, we selected 20 taxonomically diverse bacterial species and obtained the completely sequenced proteomes of two strains per species. We calculated all orthologous pairs for each of the 20 strain pairs. Per orthologous pair, we computed the conservation of two types of LCRs: compositionally biased regions (CBRs) and homorepeats (polyX). Our results show that, in bacteria, Q-rich CBRs are the most conserved, while A-rich CBRs and polyA are the most variable. LCRs have generally higher conservation when comparing pathogenic strains. However, this result depends on protein subcellular location: LCRs accumulate in extracellular and outer membrane proteins, with conservation increased in the extracellular proteins of pathogens, and decreased for polyX in the outer membrane proteins of pathogens. We conclude that these dependencies support the functional importance of LCRs in host–pathogen interactions.

scholarly journals Amikacin and bacteriophage treatment modulates outer membrane proteins composition in Proteus mirabilis biofilm

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agnieszka Maszewska ◽  
Magdalena Moryl ◽  
Junli Wu ◽  
Bin Liu ◽  
Lu Feng ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Proteus Mirabilis ◽  
Protein Biosynthesis ◽  
Outer Membrane Proteins ◽  
Wild Strain ◽  
Elongation Factor ◽  
Resistance Mechanisms ◽  
Trna Synthetases ◽  
Cytoplasmic Proteins

AbstractModification of outer membrane proteins (OMPs) is the first line of Gram-negative bacteria defence against antimicrobials. Here we point to Proteus mirabilis OMPs and their role in antibiotic and phage resistance. Protein profiles of amikacin (AMKrsv), phage (Brsv) and amikacin/phage (AMK/Brsv) resistant variants of P. mirabilis were compared to that obtained for a wild strain. In resistant variants there were identified 14, 1, 5 overexpressed and 13, 5, 1 downregulated proteins for AMKrsv, Brsv and AMK/Brsv, respectively. Application of phages with amikacin led to reducing the number of up- and downregulated proteins compared to single antibiotic treatment. Proteins isolated in AMKrsv are involved in protein biosynthesis, transcription and signal transduction, which correspond to well-known mechanisms of bacteria resistance to aminoglycosides. In isolated OMPs several cytoplasmic proteins, important in antibiotic resistance, were identified, probably as a result of environmental stress, e.g. elongation factor Tu, asparaginyl-tRNA and aspartyl-tRNA synthetases. In Brsv there were identified: NusA and dynamin superfamily protein which could play a role in bacteriophage resistance. In the resistant variants proteins associated with resistance mechanisms occurring in biofilm, e.g. polyphosphate kinase, flagella basal body rod protein were detected. These results indicate proteins important in the development of P. mirabilis antibiofilm therapies.

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