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.

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.

The binding ofProteus mirabilisnonagglutinating fimbriae to ganglio-series asialoglycolipids and lactosyl ceramide

2000 ◽  
Vol 46 (10) ◽  
pp. 961-966 ◽  
Author(s):  
Kok K Lee ◽  
Blair A Harrison ◽  
Roger Latta ◽  
Eleonora Altman
Keyword(s):  
Monoclonal Antibodies ◽  
Proteus Mirabilis ◽  
Bacterial Adhesion ◽  
Solid Phase ◽  
Mdck Cells ◽  
Upper Urinary Tract ◽  
Binding Assays ◽  
Surface Receptors ◽  
Solid Phase Binding ◽  
Asialo Gm1

Proteus mirabilis is a common opportunistic Gram-negative uropathogen that infects the upper urinary tract. We have examined the role of the nonagglutinating fimbriae (NAF) of P. mirabilis in mediating bacterial adhesion to cell surface receptors. Purified NAF of P. mirabilis were demonstrated to bind to a number of glycolipids, including asialo-GM1, asialo-GM2, and lactosyl ceramide (LacCer) in solid-phase binding assays and in thin layer chromatography (TLC) overlay assays. Furthermore, preincubation of the biotinylated NAF (Bt-NAF) with anti-NAF monoclonal antibodies resulted in inhibition of NAF binding to immobilized asialo-GM1, asialo-GM2, and LacCer. In adherence assays, P. mirabilis binding to Madin-Darby canine kidney (MDCK) cells was inhibited by murine anti-asialo-GM1 monoclonal antibodies H2G10 to about 50% of the binding level in the absence of the antibody, specific for the terminal β-galactopyranosyl residue of asialo-GM1 (Harrison et al. 1998). The results of this study suggest that NAF of P. mirabilis recognize a GalNAcβ1-4Gal moiety present in the ganglio-series of asialoglycolipids, and that the terminal β-galactopyranosyl -containing glycoconjugates play a role in NAF-mediated adherence of P. mirabilis to MDCK cells. Similarly to other bacteria, P. mirabilis NAF was also shown to express the LacCer specificity.Key words: bacterial adhesion, Proteus mirabilis, fimbriae, receptors, glycosphingolipids.

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.

scholarly journals Haemophilus somnus Possesses Two Systems for Acquisition of Transferrin-Bound Iron

2004 ◽  
Vol 186 (13) ◽  
pp. 4407-4411 ◽  
Author(s):  
Andrew Ekins ◽  
Fariborz Bahrami ◽  
Ada Sijercic ◽  
Deborah Maret ◽  
Donald F. Niven
Keyword(s):  
Solid Phase ◽  
Phase Variation ◽  
Pcr Amplification ◽  
Single Component ◽  
Receptor Expression ◽  
Binding Assays ◽  
Affinity Isolation ◽  
Haemophilus Somnus ◽  
Competition Binding ◽  
Solid Phase Binding

ABSTRACT Haemophilus somnus strain 649 was found to acquire iron from ovine, bovine, and goat transferrins (Tfs). Expression of Tf receptors, as evaluated by solid-phase binding assays, required the organisms to be grown under iron-restricted conditions in the presence of Tf. Competition binding assays revealed the presence of two distinct Tf-binding receptor systems, one specific for bovine Tf and the other capable of binding all three ruminant Tfs. Affinity isolation procedures using total membranes yielded three putative bovine Tf-binding polypeptides and one putative ovine and goat Tf-binding polypeptide. PCR amplification followed by DNA sequence analyses revealed that H. somnus strain 649 possesses genes that encode a bipartite TbpA-TbpB receptor along with a homolog of the Histophilus ovis single-component TbpA receptor. Expression of TbpB and the single-component TbpA would appear to be subject to a form of phase variation involving homopolymeric nucleotide tracts within the structural genes.

Ability of PknA, a mycobacterial eukaryotic-type serine/threonine kinase, to transphosphorylate MurD, a ligase involved in the process of peptidoglycan biosynthesis

2008 ◽  
Vol 415 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Meghna Thakur ◽  
Pradip K. Chakraborti
Keyword(s):  
Protein Kinases ◽  
Solid Phase ◽  
Morphological Changes ◽  
Binding Assays ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Peptidoglycan Biosynthesis ◽  
Vitro Binding ◽  
Solid Phase Binding

Eukaryotic-type serine/threonine protein kinases in bacteria have been implicated in controlling a host of cellular activities. PknA is one of eleven such protein kinases from Mycobacterium tuberculosis which regulates morphological changes associated with cell division. In the present study we provide the evidence for the ability of PknA to transphosphorylate mMurD (mycobacterial UDP-N-acetylmuramoyl-L-alanine:D-glutamate-ligase), the enzyme involved in peptidoglycan biosynthesis. Its co-expression in Escherichia coli along with PknA resulted in phosphorylation of mMurD. Consistent with these observations, results of the solid-phase binding assays revealed a high-affinity in vitro binding between the two proteins. Furthermore, overexpression of m-murD in Mycobacterium smegmatis yielded a phosphorylated protein. The results of the present study therefore point towards the possibility of mMurD being a substrate of PknA.

Comparative analysis of the transferrin and lactoferrin binding proteins in the family Neisseriaceae

1989 ◽  
Vol 35 (3) ◽  
pp. 409-415 ◽  
Author(s):  
Anthony B. Schryvers ◽  
B. Craig Lee
Keyword(s):  
Binding Proteins ◽  
Solid Phase ◽  
Bacterial Species ◽  
Binding Activity ◽  
Intact Cells ◽  
Human Transferrin ◽  
Affinity Isolation ◽  
Lactoferrin Receptor ◽  
Solid Phase Binding ◽  
Branhamella Catarrhalis

Intact cells of several bacterial species were tested for their ability to bind human transferrin and lactoferrin by a solid-phase binding assay using horseradish peroxidase conjugated transferrin and lactoferrin. The ability to bind lactoferrin was detected in all isolates of Neisseria and Branhamella catarrhalis but not in isolates of Escherichia coli or Pseudomonas aeruginosa. Transferrin-binding activity was similarly detected in most isolates of Neisseria and Branhamella but not in E. coli or P. aeruginosa. The expression of transferrin- and lactoferrin-binding activity was induced by addition of ethylenediamine di-o-phenylacetic acid and reversed by excess FeCl3, indicating regulation by the level of available iron in the medium. The transferrin receptor was specific for human transferrin and the lactoferrin receptor had a high degree of specificity for human lactoferrin in all species tested. The transferrin- and lactoferrin-binding proteins were identified after affinity isolation using biotinylated human transferrin or lactoferrin and streptavidin–agarose. The lactoferrin-binding protein was identified as a 105-kilodalton protein in all species tested. Affinity isolation with biotinylated transferrin yielded two or more proteins in all species tested. A high molecular mass protein was observed in all isolates, and was of similar size (approximately 98 kilodaltons) in all species of Neisseria but was larger (105 kilodaltons) in B. catarrhalis.Key words: iron, Neisseria, transferrin, lactoferrin, receptor.

Ultrastructural Evidence for Proteoglycans Mediating an Attachment of Type VI Collagen to Banded Collagen Fibrils

1997 ◽  
Vol 3 (S2) ◽  
pp. 153-154
Author(s):  
Douglas R. Keene ◽  
Catherine C. Ridgway ◽  
Renato V. Iozzo
Keyword(s):  
Dermatan Sulfate ◽  
Core Protein ◽  
Solid Phase ◽  
Collagen Fibrils ◽  
Binding Assays ◽  
Connective Tissues ◽  
Type Vi Collagen ◽  
Dermatan Sulfate Proteoglycan ◽  
Individual Type ◽  
Solid Phase Binding

Immunolocalizaton studies of type VI collagen in skin have previously demonstrated that type VI collagen forms a flexible network that anchors large interstitial structures such as nerves, blood vessels, and collagen fibers into the surrounding connective tissues matrix. The purpose of this study is to determine if individual type VI collagen microfilaments might be connected to banded collagen fibrils, thereby stabilizing the network.Solid phase binding assays suggest a specific, high affinity interaction between the core protein of the dermatan sulfate proteoglycan decorin and type VI collagen, and immunocytochemical studies in fetal and neonate rabbit cornea suggest an association of decorin with type VI microfilaments. Other studies in skin and perichondrium have localized decorin to a region between the d and e bands of banded collagen fibrils. However, no direct documentation has demonstrated a specific structural interaction between type VI microfilaments and banded collagen fibrils. We, therefore, sought to determine if type VI microfilaments cross banded collagen fibrils between the “d” and “e” bands.

scholarly journals Fibulin-1 mediates platelet adhesion via a bridge of fibrinogen

Blood ◽  
1996 ◽  
Vol 88 (7) ◽  
pp. 2569-2577 ◽  
Author(s):  
S Godyna ◽  
M Diaz-Ricart ◽  
WS Argraves
Keyword(s):  
Extracellular Matrix ◽  
Vascular Injury ◽  
Whole Blood ◽  
Platelet Adhesion ◽  
Solid Phase ◽  
Blood Perfusion ◽  
General Mechanism ◽  
Binding Assays ◽  
Solid Phase Binding ◽  
Coated Surfaces

Fibulin-1 is a component of the extracellular matrix that surrounds vascular smooth muscle. This observation, along with the recent finding that fibulin-1 can bind fibrinogen (J Biol Chem 270:19458, 1995), prompted investigation into the potential role of fibulin-1 as a thrombogenic agent. In perfusion chamber assays, platelets in whole blood under flow conditions attached and spread on surfaces coated with fibulin-1. This adhesion was completely blocked by fibulin-1 antibodies. Platelets free of plasma did not attach to fibulin-1 coated surfaces; however, with the addition of fibrinogen, platelet adhesion to fibulin-1 took place. When detergent extracts of platelets were subjected to fibulin-1-Sepharose affinity chromatography, the integrin alpha IIb beta 3 was selected. Solid phase binding assays using purified components showed that integrin alpha IIb beta 3 could not bind directly to fibulin-1 but in the presence of fibrinogen the integrin bound to fibulin-1-coated surfaces. Monoclonal alpha IIb beta 3 antibodies capable of blocking its interaction with fibrinogen completely blocked platelet adhesion to fibulin-1 in both whole blood perfusion and static adhesion assays. The results show that fibulin-1 can support platelet attachment via a bridge of fibrinogen to the platelet integrin alpha IIb beta 3. When fibroblast monolayers containing extracellular matrix-incorporated fibulin-1 were used as adhesion substrates, platelet adhesion in the presence of fibrinogen could be inhibited by 30% using antibodies to fibulin-1. Following vascular injury, fibulin-1 present in the extracellular matrix of the vessel wall may therefore interact with plasma fibrinogen and promote platelet adhesion, leading to the formation of a platelet plug. Thus, fibulin-1 joins the list of matrix proteins including collagens I and IV and fibronectin that mediate platelet adhesion via a plasma protein bridge. This bridging phenomenon may represent a general mechanism by which platelets interact with exposed subendothelial matrices following vascular injury.

Immobilized whole algal cells for solid-phase binding assays

1986 ◽  
Vol 86 (2) ◽  
pp. 171-177 ◽  
Author(s):  
Paul Bubrick ◽  
Leon Goldstein ◽  
Asher Frensdorff
Keyword(s):  
Solid Phase ◽  
Binding Assays ◽  
Solid Phase Binding

Interaction between the pili of Pseudomonas aeruginosa PAK and its carbohydrate receptor β-D-GalNAc(1->4) β-D-Gal analogs

1998 ◽  
Vol 44 (3) ◽  
pp. 307-311 ◽  
Author(s):  
Frank Schweizer ◽  
Hailong Jiao ◽  
Ole Hindsgaul ◽  
Wah Y Wong ◽  
Randall T Irvin
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Inhibitory Concentration ◽  
Binding Assay ◽  
Solid Phase ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Surface Receptors ◽  
Order Of Magnitude ◽  
Epithelial Cell Surface ◽  
Solid Phase Binding

Pseudomonas aeruginosa employs pili to mediate adherence to epithelial cell surface receptors. Previously, it has been shown that the pilus adhesin of P. aeruginosa PAK binds to the ganglioside asialo-GM1. In particular, it was found that the carbohydrate sequence β-D-GalNAc(1->4) β-D-Gal is the minimal carbohydrate receptor sequence of asialo-GM1. To study the binding specificity of P. aeruginosa, O-modified and N-modified sugar analogs, where each hydroxyl group was substituted either by O-methyl or O-propyl and the acetamido group was changed to a propionamido group, were synthesized. The sugar analogs were evaluated as inhibitors in a competitive solid phase binding assay. The results demonstrate that the pili of P. aeruginosa PAK accepts a variety of sugar analogs possessing the sequence β-D-GalNAc(1->4) β-D-Gal. Most sugar analogs bind with a similar order of magnitude (50% inhibitory concentration (IC50) = 60-130 μM) except for the 2-O-propyl derivative 7 (IC50 = 8 ± 4 μM) compared with an IC50 of 79 ± 18 μM for the native compound. The significant increase in binding affinity of 2-O-propyl derivative 7 suggests that improved inhibitors of adhesion may be prepared by introducing a hydrophobic side chain at the 2-position of galactose.Key words: Pseudomonas aeruginosa, pili, adhesion, carbohydrate.

Sign in / Sign up

Export Citation Format

Share Document