Contact-dependent acquisition of transferrin-bound iron by two strains of Haemophilus parasuis

1995 ◽  
Vol 41 (1) ◽  
pp. 70-74 ◽  
Author(s):  
N. Charland ◽  
C. G. D'silva ◽  
R. A. Dumont ◽  
D. F. Niven
Keyword(s):  
Type Strain ◽  
Iron Acquisition ◽  
Outer Membrane Proteins ◽  
Transferrin Receptors ◽  
Haemophilus Parasuis ◽  
Isolation And Identification ◽  
Isolation Technique ◽  
Affinity Isolation ◽  
Sds Page ◽  
Bovine Transferrin

Two strains of Haemophilus parasuis, namely, the type strain (ATCC 19417) and strain E751, were investigated with respect to iron acquisition. Both strains produced iron-repressible outer membrane proteins and could acquire iron from porcine transferrin but not from porcine lactoferrin. Neither strain used bovine transferrin, and human transferrin was used to only a very limited extent, if at all. In all cases, iron acquisition from transferrin required direct contact between the organisms and the protein. An affinity isolation technique based on biotinylated porcine transferrin plus streptavidin-agarose, followed by SDS-PAGE, allowed the isolation and identification of two potential porcine transferrin binding polypeptides (94 and 60 kDa) from total membranes derived from the type strain grown under iron-restricted conditions but only one (96 kDa) from strain E751. Each of these polypeptides was iron repressible and was not isolated when biotinylated human or bovine transferrin was used instead of biotinylated porcine transferrin. It is concluded that both strains acquire transferrin-bound iron by means of siderophore-independent mechanisms and that the isolated polypeptides represent porcine transferrin receptor components.Key words: Haemophilus parasuis, iron, transferrin, receptors.

Production of transferrin receptors byHistophilus ovis: three of five strains require two signals

2001 ◽  
Vol 47 (5) ◽  
pp. 417-423 ◽  
Author(s):  
Andrew Ekins ◽  
Donald F Niven
Keyword(s):  
Solid Phase ◽  
Iron Acquisition ◽  
Isolation Procedure ◽  
Transferrin Receptors ◽  
Binding Assays ◽  
Surface Receptors ◽  
Iron Restriction ◽  
Affinity Isolation ◽  
Solid Phase Binding ◽  
Bovine Transferrin

Five strains of Histophilus ovis (9L, 642A, 714, 5688T, and 3384Y) were investigated with respect to iron acquisition. All strains used ovine, bovine, and goat transferrins (Tfs), but not porcine or human Tfs, as iron sources for growth. In solid phase binding assays, total membranes from only two (9L and 642A) of the five strains, grown under iron-restricted conditions, were able to bind Tfs (ovine, bovine, and goat, but not porcine or human). However, when the organisms were grown under iron-restricted conditions in the presence of bovine transferrin (Tf), total membranes from all strains exhibited Tf binding (as above); competition experiments demonstrated that all three Tfs (ovine, bovine, and goat) were bound by the same receptor(s). Membranes from organisms grown under iron-replete conditions in the presence or absence of bovine Tf failed to bind any of the test Tfs. An affinity-isolation procedure allowed the isolation of two putative Tf-binding polypeptides (78 and 66 kDa) from total membranes of strains 9L and 642A grown under iron-restricted conditions, and from membranes of all strains if the growth medium also contained Tf. It is concluded that all strains tested acquire Tf-bound iron by means of siderophore-independent mechanisms involving surface receptors analogous to the Tf-binding proteins (TbpA and TbpB) found in comparable organisms; although iron restriction alone is sufficient to promote the expression of these proteins by strains 9L and 642A, their production by strains 714, 5688T, and 3384Y appears to require two signals, iron restriction and the presence of Tf.Key words: Histophilus ovis, iron acquisition, transferrins, receptors, regulation.

scholarly journals Preparation and Characterization of Neisseria meningitidis Mutants Deficient in Production of the Human Lactoferrin-Binding Proteins LbpA and LbpB

1998 ◽  
Vol 180 (12) ◽  
pp. 3080-3090 ◽  
Author(s):  
Robert A. Bonnah ◽  
Anthony B. Schryvers
Keyword(s):  
Neisseria Meningitidis ◽  
Binding Proteins ◽  
Binding Protein ◽  
Iron Acquisition ◽  
Outer Membrane Proteins ◽  
Mammalian Host ◽  
Human Pathogens ◽  
Sequence Comparisons ◽  
Isolation Technique

ABSTRACT Pathogenic members of the family Neisseriaceae produce specific receptors facilitating iron acquisition from transferrin (Tf) and lactoferrin (Lf) of their mammalian host. Tf receptors are composed of two outer membrane proteins, Tf-binding proteins A and B (TbpA and TbpB; formerly designated Tbp1 and Tbp2, respectively). Although only a single Lf-binding protein, LbpA (formerly designated Lbp1), had previously been recognized, we recently identified additional bacterial Lf-binding proteins in the human pathogens Neisseria meningitidis and Moraxella catarrhalis and the bovine pathogen Moraxella bovis by a modified affinity isolation technique (R. A. Bonnah, R.-H. Yu, and A. B. Schryvers, Microb. Pathog. 19:285–297, 1995). In this report, we characterize an open reading frame (ORF) located immediately upstream of theN. meningitidis B16B6 lbpA gene. Amino acid sequence comparisons of various TbpBs with the product of the translated DNA sequence from the upstream ORF suggests that the region encodes the Lf-binding protein B homolog (LbpB). The LbpB from strain B16B6 has two large stretches of negatively charged amino acids that are not present in the various transferrin receptor homologs (TbpBs). Expression of the recombinant LbpB protein as a fusion with maltose binding protein demonstrated functional Lf-binding activity. Studies with N. meningitidis isogenic mutants in which thelbpA gene and the ORF immediately upstream oflbpA (putative lbpB gene) were insertionally inactivated demonstrated that LbpA, but not LbpB, is essential for iron acquisition from Lf in vitro.

Transferrin receptors on ruminant pathogens vary in their interaction with the C-lobe and N-lobe of ruminant transferrins

1994 ◽  
Vol 40 (7) ◽  
pp. 532-540 ◽  
Author(s):  
Ronghua Yu ◽  
Anthony B. Schryvers
Keyword(s):  
Pasteurella Multocida ◽  
Iron Acquisition ◽  
Receptor Protein ◽  
Receptor Interaction ◽  
Binding Assays ◽  
Single Receptor ◽  
Affinity Isolation ◽  
Moraxella Bovis ◽  
Receptor Binding Specificity ◽  
Bovine Transferrin

The interaction between ruminant transferrins and receptor proteins on the surface of the ruminant pathogens Pasteuerella haemolytica, Haemophilus somnus, Pasteurella multocida, Haemophilus agnii, and Moraxella bovis was evaluated by a combination of binding assays and affinity isolation procedures. Membranes isolated from P. haemolytica, P. multocida, and H. agnii were capable of binding sheep, goat, and cattle transferrins whereas binding by membranes from H. somnus and M. bovis was specific for bovine transferrin. Proteolytically derived bovine transferrin C-lobe was capable of inhibiting the interaction between bovine transferrin and both Tbpl and Tbp2 from P. haemolytica and M. bovis but only Tbpl from H. somnus and P. multocida. Proteolytically derived N-lobe inhibited the binding of P. multocida and H. somnus Tbp2 to bovine transferrin and the binding of bovine transferrin to the single receptor protein identified in H. agnii. The implications of these results regarding the nature of the ligand–receptor interaction and similarities of this interaction with ligand–receptor interactions in different species are discussed.Key words: iron acquisition, transferrin receptor, binding specificity, Pasteurella, ruminants.

Advanced Fault Isolation Technique Using Electro-Optical Terahertz Pulse Reflectometry (EOTPR) for 2D and 2.5D Flip-Chip Package

2012 ◽  
Author(s):  
Lihong Cao ◽  
Manasa Venkata ◽  
Meng Yeow Tay ◽  
Wen Qiu ◽  
J. Alton ◽  
...  
Keyword(s):  
Time Domain ◽  
Flip Chip ◽  
Time Domain Reflectometry ◽  
Fault Isolation ◽  
Experimental Results ◽  
Terahertz Pulse ◽  
Isolation And Identification ◽  
Isolation Technique ◽  
Non Destructive

Abstract Electro-optical terahertz pulse reflectometry (EOTPR) was introduced last year to isolate faults in advanced IC packages. The EOTPR system provides 10μm accuracy that can be used to non-destructively localize a package-level failure. In this paper, an EOTPR system is used for non-destructive fault isolation and identification for both 2D and 2.5D with TSV structure of flip-chip packages. The experimental results demonstrate higher accuracy of the EOTPR system in determining the distance to defect compared to the traditional time-domain reflectometry (TDR) systems.

Immunogenicity and protective efficacy of recombinant Haemophilus parasuis SH0165 putative outer membrane proteins

Vaccine ◽  
2013 ◽  
Vol 31 (2) ◽  
pp. 347-353 ◽  
Author(s):  
Shulin Fu ◽  
Minmin Zhang ◽  
Juan Xu ◽  
Jiwen Ou ◽  
Yan Wang ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Protective Efficacy ◽  
Outer Membrane Proteins ◽  
Haemophilus Parasuis

scholarly journals N-Acetylcysteine Selectively Antagonizes the Activity of Imipenem in Pseudomonas aeruginosa by an OprD-Mediated Mechanism

2015 ◽  
Vol 59 (6) ◽  
pp. 3246-3251 ◽  
Author(s):  
Jerónimo Rodríguez-Beltrán ◽  
Gabriel Cabot ◽  
Estela Ynés Valencia ◽  
Coloma Costas ◽  
German Bou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Bacterial Species ◽  
Outer Membrane Proteins ◽  
Antibiotic Activity ◽  
Simultaneous Treatment ◽  
Content Type ◽  
Sds Page

ABSTRACTThe modulating effect ofN-acetylcysteine (NAC) on the activity of different antibiotics has been studied inPseudomonas aeruginosa. Our results demonstrate that, in contrast to previous reports, only the activity of imipenem is clearly affected by NAC. MIC and checkerboard determinations indicate that the NAC-based modulation of imipenem activity is dependent mainly on OprD. SDS-PAGE of outer membrane proteins (OMPs) after NAC treatments demonstrates that NAC does not modify the expression of OprD, suggesting that NAC competitively inhibits the uptake of imipenem through OprD. Similar effects on imipenem activity were obtained withP. aeruginosaclinical isolates. Our results indicate that imipenem-susceptibleP. aeruginosastrains become resistant upon simultaneous treatment with NAC and imipenem. Moreover, the generality of the observed effects of NAC on antibiotic activity was assessed with two additional bacterial species,Escherichia coliandAcinetobacter baumannii. Caution should be taken during treatments, as the activity of imipenem may be modified by physiologically attainable concentrations of NAC, particularly during intravenous and nebulized regimes.

scholarly journals A Plasmid-Encoded FetMP-Fls Iron Uptake System Confers Selective Advantages to Salmonella enterica Serovar Typhimurium in Growth under Iron-Restricted Conditions and for Infection of Mammalian Host Cells

2020 ◽  
Vol 8 (5) ◽  
pp. 630
Author(s):  
Vanesa García ◽  
Ana Herrero-Fresno ◽  
Rosaura Rodicio ◽  
Alfonso Felipe-López ◽  
Ignacio Montero ◽  
...  
Keyword(s):  
Iron Content ◽  
Salmonella Enterica ◽  
Iron Uptake ◽  
Type Strain ◽  
Wild Type Strain ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Iron Acquisition ◽  
Clinical Strain ◽  
Wild Type ◽  
Serovar Typhimurium

The resistance plasmid pUO-StVR2, derived from virulence plasmid pSLT, is widespread in clinical isolates of Salmonella enterica serovar Typhimurium recovered in Spain and other European countries. pUO-StVR2 carries several genes encoding a FetMP-Fls system, which could be involved in iron uptake. We therefore analyzed S. Typhimurium LSP 146/02, a clinical strain selected as representative of the isolates carrying the plasmid, and an otherwise isogenic mutant lacking four genes (fetMP-flsDA) of the fetMP-fls region. Growth curves and determination of the intracellular iron content under iron-restricted conditions demonstrated that deletion of these genes impairs iron acquisition. Thus, under these conditions, the mutant grew significantly worse than the wild-type strain, its iron content was significantly lower, and it was outcompeted by the wild-type strain in competition assays. Importantly, the strain lacking the fetMP-flsDA genes was less invasive in cultured epithelial HeLa cells and replicated poorly upon infection of RAW264.7 macrophages. The genes were introduced into S. Typhimurium ATCC 14028, which lacks the FetMP-Fls system, and this resulted in increased growth under iron limitation as well as an increased ability to multiply inside macrophages. These findings indicate that the FetMP-Fls iron acquisition system exceeds the benefits conferred by the other high-affinity iron uptake systems carried by ATCC 14028 and LSP 146/02. We proposed that effective iron acquisition by this system in conjunction with antimicrobial resistance encoded from the same plasmid have greatly contributed to the epidemic success of S. Typhimurium isolates harboring pUO-StVR2.

scholarly journals Leuconostoc durionis sp. nov., a heterofermenter with no detectable gas production from glucose

2005 ◽  
Vol 55 (3) ◽  
pp. 1267-1270 ◽  
Author(s):  
J. J. Leisner ◽  
M. Vancanneyt ◽  
R. Van der Meulen ◽  
K. Lefebvre ◽  
K. Engelbeen ◽  
...  
Keyword(s):  
Dna Hybridization ◽  
Type Strain ◽  
Sequence Similarity ◽  
Gene Sequencing ◽  
16S Rrna Gene Sequencing ◽  
Gas Production ◽  
Rrna Gene ◽  
Nearest Neighbour ◽  
Sds Page ◽  
Rrna Gene Sequencing

Three lactic acid bacterial (LAB) strains obtained from a Malaysian acid-fermented condiment, tempoyak (made from pulp of the durian fruit), showed analogous but distinct patterns after screening by SDS-PAGE of whole-cell proteins and comparison with profiles of all recognized LAB species. 16S rRNA gene sequencing of one representative strain showed that the taxon belongs phylogenetically to the genus Leuconostoc, with its nearest neighbour being Leuconostoc fructosum (98 % sequence similarity). Biochemical characteristics and DNA–DNA hybridization experiments demonstrated that the strains differ from Leuconostoc fructosum and represent a single, novel Leuconostoc species for which the name Leuconostoc durionis sp. nov. is proposed. The type strain is LMG 22556T (=LAB 1679T=D-24T=CCUG 49949T).

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