Transmembrane permeability channels across the outer membrane of Haemophilus influenzae type b

Vachon, Vincent; Lyew, Darwin; Coulton, James W.

doi:10.1128/jb.162.3.918-924.1985

Cited by 89 publications

(40 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Differences in the size of the porin channels appear to account for some of the differences observed in the minimum inhibitory concentrations of various gramnegative bacteria. For example, Huemophilus influenzae is thought to be much more susceptible to p-lactam antibiotics than E. coli due to the presence of larger porin channels (44). Specific mutations of gene(s) coding for the porin proteins can further impair the entry of hydrophobic penicillins into the cell and result in an increase in the minimum inhibitory concentration of the antibiotic for the organism.…”

Section: Resistance To Tetracycline Antibioticsmentioning

confidence: 99%

The acquisition of antibiotic resistance in the periodontal microflora

Walker¹

1996

Periodontology 2000

188

159

View full text Add to dashboard Cite

Section: Resistance To Tetracycline Antibioticsmentioning

confidence: 99%

The acquisition of antibiotic resistance in the periodontal microflora

Walker¹

1996

Periodontology 2000

188

159

View full text Add to dashboard Cite

“…The purification scheme for porin of Hib strain ATCC9795 as described by Vachon et at. (1985) yielded a single species of protein when stained with Coomassie Brilliant Blue.…”

Section: Monoclonal Antibodies Against Hib Porinmentioning

confidence: 99%

“…We have studied the Hib porin extensively and have shown that it has a molecular mass exclusion limit to solutes greater than 1400Da (Vachon et at., 1985). a cross-sectional diameter of 0.9 nm (as determined by reconstitution into black lipid membranes; Vachon etai, 1986), and a trimeric organization in the outer membrane (Vachon et at.. 1988).…”

Section: Introductionmentioning

confidence: 99%

Monoclonal antibodies specific to porin of Haemophilus influenzae type b: localization of their cognate epitopes and tests of their biological activities

Srikumar

Chin

Vachon

et al. 1992

Molecular Microbiology

View full text Add to dashboard Cite

The major outer membrane protein of Haemophilus influenzae type b (Hib) is porin (Mr 38,000, 341 amino acids). To identify antigenic determinants on Hib porin that might be exposed at the bacterial cell surface, seven mouse monoclonal anti-Hib porin antibodies were generated. The monoclonal antibodies were tested for their binding to intact cells by flow cytometry; all but one bound to the cell surface. Digestions of Hib porin with cyanogen bromide, hydroxylamine or trypsin generated fragments, the identities of which were confirmed by microsequencing of the amino termini. Following electrophoresis and immunoblotting of the fragments, the specificities of the monoclonal antibodies for their cognate sequences were determined. The porin gene ompP2 was expressed in the baculovirus expression vector system; the recombinant porin was recognized by all of the monoclonal antibodies. Deletions were created by omega mutagenesis of ompP2, generating proteins truncated after amino acids 139, 174, 182, and 264. These deletion proteins were tested for reactivities with the monoclonal antibodies, thereby establishing the boundaries of three antigenic determinants that were recognized by the monoclonals: domain (i), amino acids 104-139; domain (ii) amino acids 162-174; and domain (iii), amino acids 267-341. The biological activities of monoclonal antibodies that were representative of these three classes were tested for their bactericidal activity in complement-mediated lysis of whole cells. The monoclonal antibodies were also tested for their immunoprotective properties in the infant rat model of bacteraemia. Although the monoclonal antibodies were surface-binding, they were neither bactericidal nor protective.

show abstract

“…Reconstituted outer membranes of gram-negative bacteria for example have exclusion limits to passive diffusion that range between 600 and 3000 g mol-'. [33][34][35] This suggests that only oligomeric tannins can effectively penetrate bacteria. Penetration is also an important factor involved in the interactions of tannins with complex proteins.…”

Section: Detoxification Of Bark Tanninsmentioning

confidence: 99%

Oxidative detoxification of aqueous bark extracts. Part I: Autoxidation

Field¹,

Lettinga²,

Habets

1990

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

The aqueous extracts of bark were studied as a model for wet debarking wastewater. These extracts are known to contain a high concentration of methanogenic toxic tannins. The objective of this study was to modify the native bark tannins (oligomers) with oxidative methods in order to decrease their methanogenic toxicity. The tannins were polymerized by autoxidation, forming colored high-molecular-weight tannins that were non-toxic to methanogenic bacteria. The autoxidation of pine bark extracts provided complete detoxification. In the case of spruce bark, which was responsible for extracts of higher toxicity, the detoxification was either partial or complete depending on the specific sample of spruce bark porn which the extract was prepared. The autoxidation of birch bark did not result in significant detoxification. Although the oligomeric tannins were effectively polymerized, birch bark extracts contain non-tannin toxins which were not affected by the autoxidation and evidence that highly toxic intermediates were formed during the high pH autoxidation of birch bark extracts is presented.Autoxidative detoxification offers an interesting approach for pretreating coniferous bark wastewaters. The oxidation reactions of the pretreatment serve to detoxify the largely non-BOD tannin paction. Thus the methanogenic * Present address: Department of Chemical Engineering, Universidad Autonoma de Barcelona, 08193Bellaterra (Barcelona), Spain. 15 J . Chem. Tech. Biotechnol. 0268-2575/90/$03.50 0 1990 Society of Chemical Industry. Printed in Great Britain J . A. Field, G . Lettinga, L. H . A . Hahets bacteria are not inhibited during the anaerobic wastewater treatment for removing BOD.

show abstract

Transmembrane permeability channels across the outer membrane of Haemophilus influenzae type b

Cited by 89 publications

References 29 publications

The acquisition of antibiotic resistance in the periodontal microflora

The acquisition of antibiotic resistance in the periodontal microflora

Monoclonal antibodies specific to porin of Haemophilus influenzae type b: localization of their cognate epitopes and tests of their biological activities

Oxidative detoxification of aqueous bark extracts. Part I: Autoxidation

Contact Info

Product

Resources

About