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K Vosbeck

Publications and source records attributed to K Vosbeck.

48 records · Page 3Linked to original sources
PubMed1983

Properties of pili from Escherichia coli SS142 that mediate mannose-resistant adhesion to mammalian cells.

We isolated pili from Escherichia coli SS142. These pili had a diameter of 6 nm and an average length of 400 nm. They were composed of subunits with a molecular weight of 18,000. Their amino acid composition was determined; methionine and proline were not detected. The isolated pili retained mannose-resistant hemagglutinating activity. Proteolytic digestion and glutaraldehyde fixation led to partial or complete loss of the hemagglutinating activity of the pili without causing any detectable damage to their supramolecular structure, which was only disintegrated by treatment with hot sodium dodecyl sulfate. The hemagglutinating activity of E. coli SS142 was inhibited by the glycoproteins fetuin and Tamm-Horsfall protein, as well as by the glycolipids phytyl lactoside, dansyl-sphingosine lactoside, and digalactosyl diglyceride. Isolated pili inhibited the adhesion of the homologous strain E. coli SS142 to Intestine 407 cell monolayers, but did not inhibit the adhesion of E. coli strain B-413, B-506, or 2699. This indicates that E. coli SS142 binds to a receptor different from those recognized by the other strains and that mannose-resistant adhesion to tissue culture cells can be classified into different subtypes.

Adhesiveness↗
PubMed1982

Swainsonine prevents the processing of the oligosaccharide chains of influenza virus hemagglutinin.

Swainsonine, an indolizidine alkaloid, inhibits the alpha-mannosidase that is involved in glycoprotein processing. Thus, in cultured animal cells, this alkaloid causes an increase in the surface content of high mannose glycoproteins and a decrease in the amount of complex type glycoproteins (Elbein, A. D., Solf, R., Dorling, P. R., and Vosbeck, K. (1982) Proc. Natl. Acad. Sci. U. S. A., 78, 7393-7397). In this report, the effect of swainsonine on the synthesis virus hemagglutinins was examined. Primary calf kidney cultures were infected with influenza virus and viral replication was allowed to proceed in the absence or presence of swainsonine. Several hours after the addition of swainsonine, [2-3H]mannose or [6-3H]glucosamine were added to label the hemagglutinins and the mature virus particles were isolated. Virus particles raised in the presence of this alkaloid had the same infectivity and hemagglutination titer as virus particles from control cells. However, when the hemagglutinins were examined on sodium dodecyl sulfate gels, the major hemagglutinin (HA0) and its subunits, HA1 and HA2, from swainsonine-treated cells, migrated faster, indicating that they were of lower molecular weights. The labeled hemagglutinins were digested with pronase and the resulting glycopeptides were chromatographed on Bio-Gel P-4. Both the mannose-labeled and glucosamine-labeled glycopeptides from swainsonine-treated virus migrated more slowly on these columns than those of controls cells, suggesting that they were altered in structure. Furthermore, when the glycopeptides were digested with endoglucosaminidase H, 90% of the glycopeptides from swainsonine-treated cells were susceptible to this enzyme, whereas only 30% of those from control cells were digested. The major oligosaccharide released from inhibited cells by endoglucosaminidase H was digestible with alpha-mannosidase, whereas that of control cells was resistant to this enzyme. However, the control cell glycopeptide was digested by a combination of neuraminidase, beta-galactosidase, beta-N-acetylhexosaminidase, and alpha-mannosidase. These data show that swainsonine prevents the formation of complex glycoproteins and gives rise to increased amounts of high-mannose glycoproteins.

Alkaloids↗
PubMed1982

An assay for measuring specific adhesion of an Escherichia coli strain to tissue culture cells.

Escherichia coli SS142 has been found to adhere specifically to the human epithelioid tissue culture cell line Intestine 407, but not to other tissue culture cells. This paper describes an accurate, reproducible and objective method of assessing the rate of adhesion of radiolabelled bacteria to these cellular monolayers. Adhesion was found to be linear with time for 60 min and with bacterial concentrations up to 10(9) bacteria/ml. The binding appeared to be irreversible. Adhesion was not affected by changes in the composition of the medium, its pH or ionic strength, or by the assay temperature within physiological limits, but was diminished at very high ionic strength or low temperature. It increased with increasing cell density of the monolayers. Under appropriate conditions the assay could be used for comparative determinations of the rate of adhesion of different, or differently treated bacteria.

Cell Count↗
PubMed1982

Effects of low concentrations of antibiotics on Escherichia coli adhesion.

We have previously shown that subinhibitory concentrations of antibiotics may influence the adhesion of Escherichia coli SS142 to human epithelioid tissue culture cells. This report shows that these effects are not limited to E. coli SS142 or to our tissue culture system. Most of the 10 E. coli strains studied showed decreased adhesion to Intestine 407 tissue culture cells after growth in 25% of the minimum inhibitory concentration of streptomycin, tetracycline, trimethoprimsulfametrole, chloramphenicol, and clindamycin. Nalidixic acid at 25% of the minimum inhibitory concentration caused an increase of adhesion. The hemagglutinating activity of the five hemagglutinating strains and the adhesiveness of E. coli SS142 to human buccal cells were similarly affected by low concentrations of the above-mentioned antibiotics. We conclude that E. coli adhesion to human epithelioid tissue culture cells is a valid model of bacterial adhesion because of its high accuracy and reproducibility.

Anti-Bacterial Agents↗
PubMed1981

Swainsonine: an inhibitor of glycoprotein processing.

Swainsonine, an indolizidine alkaloid, inhibits the processing of asparagine-linked glycoproteins in both cell-free extracts and animal cells in culture. Thus, in a liver particulate enzyme preparation, swainsonine at 0.1-1.0 microM inhibited the mannosidase that releases [3H]mannose from a high mannose glycopeptide but only slightly inhibited the release of glucose from a glucose-labeled glycopeptide. MDCK and Chinese hamster ovary cells in culture incorporate [2-3H]mannose and [6-3H]glucosamine into both high mannose and complex types of oligosaccharides. When these cells were incubated with swainsonine and then labeled with mannose or glucosamine, there was a dramatic decrease in the amount of label in the complex type of glycopeptide and a substantial increase in the radioactivity in the high mannose type. This change was monitored by the increase in radioactivity that became susceptible to digestion by endoglucosaminidase H with increasing concentrations of swainosine. The endoglucosaminidase H-released oligosaccharide(s) from swainsonine-treated cells was larger and more homogeneous than that from controls and eluted from Bio-Gel P-4 at the position of Man9GlcNAc. Several tissue culture cell lines were grown in the presence of swainsonine to determine its effect on cell surface glycoproteins. Cells grown in the alkaloid showed an increased capacity to bind Escherichia coli B886, a bacterium that binds to high mannose glycoproteins. These cells also showed an increasing binding of [3H]concanavalin A.

Alkaloids↗
PubMed1981

Escherichia coli adhesion to Saccharomyces cerevisiae and mammalian cells: role of piliation and surface hydrophobicity.

A number of Escherichia coli strains isolated from patients with urinary tract infections, bacteremia, or diarrhea were studied with respect to their (i) capacity to agglutinate human AB, bovine, and guinea pig erythrocytes as well as yeast (Saccharomyces cerevisiae) cells; (ii) adhesion to monolayers of cells from human intestine (intestine 407; ATCC CCL6), monkey kidney (Vero; ATCC CCL81), feline embryo (Flow no. 05-552), and porcine kidney (PK1; ATCC CRL1392) and of primary rat kidney cell cultures; and (iii) surface hydrophobicity as measured by hydrophobic interaction chromatography. No correlation could be found between the capacity of the bacteria to adhere to the different cultured mammalian cells and their agglutination patterns. The results indicated not only a complexity of bacterial receptors on the eucaryotic cells, but also a multiplicity of bacterial adhesions as expressed by the selectivity of bacterial binding. Binding of bacteria was found to be attributed to the presence of pili on the bacterial surface. It was observed that the bacteria were differently piliated: some had only common type I or related pili which gave rise to mannose-sensitive (MS) adhesion or agglutination (MS pili), some had only pili which gave rise to mannose-resistant (MR) adhesion or agglutination (MR pili), and some had both MS and MR pili. Bacteria with MS pili were more hydrophobic than those with MR pili or with none at all.

Agglutination↗
PubMed1981

Bacterial adhesion in the pathogenesis of infective endocarditis. Effect of subinhibitory antibiotic concentrations on streptococcal adhesion in vitro and the development of endocarditis in rabbits.

Bacterial adhesion to the constituents of nonbacterial thrombotic endocarditis (NBTE) is important in the pathogenesis of endocarditis. Subinhibitory concentrations (subMIC) of some antibiotics decrease bacterial adhesion to epithelial cells in vitro. We utilized an in vitro assay system to study the effect of subMIC of various antibiotics on streptococcal adhesion to a fibrin-platelet matrix (simulating NBTE). The results were (a) bacterial adhesion of Streptococcus sanguis and Streptococcus faecalis to NBTE was significantly reduced by vancomycin, penicillin, tetracycline, chloramphenicol and streptomycin (P less than 0.01 vs. controls) but not rifampin or trimethoprimsulfametrole; (b) the effect was dose-dependent and increased with duration of exposure to antibiotic; (c) reduction in bacterial adhesion did not correlate with altered retention by hydrophobic-interaction chromatography. This reduction in adhesion correlated with a diminished capacity of subMIC exposed Streptococcus sanguis (1/4 vancomycin minimum inhibitory concentration (MIC) X 4 h) to produce endocarditis in vivo. After intravenous inoculation of 10(6) colony-forming units of preincubated organisms into rabbits with traumatized aortic valves, 6 of 22 developed endocarditis vs. 17 of 22 controls (P = 0.03). These results may be relevant to prophylaxis of endocarditis since exposure of bacteria to subMIC of various antibiotics may reduce bacterial adherence both, to mucosal surfaces, and to damaged cardiac valves.

Animals↗
PubMed1976

Assay of intercellular adhesiveness using cell-coated Sephadex beads as collecting particles.

A simple, rapid and precise method, based on a previous method, for measuring relative rates of intercellular adhesion is described. DEAE-Sephadex beads were treated with nitrocellulose in order to allow cells to grow on their surfaces. Balb/c 3T3 and Balb/c 3T12 cells were used to characterize the assay. They formed confluent cell layers on nitrocellulose-treated DEAE-Sephadex. These cell-coated beads were employed to collect 32P-labelled cells from single cell suspensions. Since they formed statistically uniform, large collecting surfaces, the collection of labelled cells was markedly improved as compared to the original assay. The cell-coated beads collected a large percentage of the labelled cells in a short time. The percentage of cells collected was independent of the concentration of labelled cells in the assay mixture, and the collection was linear for approximately 60 min. The variability between replicate assays was usually +/- 5%. The assay allows the rapid and precise determination of intercellular adhesion in large numbers of individual samples. These features make it useful to screen for effects of different treatments on intercellular adhesions.

Cadmium↗
PubMedDate not supplied

Effects of subminimal inhibitory concentrations of antibiotics on adhesiveness of Escherichia coli in vitro.

The adhesion of radiolabeled Escherichia coli (strain SS142) to monolayers of Intestine 407, a human epithelioid tissue culture cell line, was investigated. In this assay the adhesion of bacteria grown in the presence of subminimal inhibitory concentrations of tetracycline, clindamycin,, or trimethoprim-sulfametrole was reduced in a manner that was dose dependent. In contrast, at such concentrations nalidixic acid enhanced the adhesion of this bacterial strain, and other antibiotics-e.g., penicillin G, ampicillin, mecillinam, cephacetrile, cephalexin, cefotaxime, chloramphenicol, and streptomycin-did not affect its adhesiveness.

Adhesiveness↗
PubMedDate not supplied

Neutralization of interleukin-1 beta activity in vivo with a monoclonal antibody alleviates collagen-induced arthritis in DBA/1 mice and prevents the associated acute-phase response.

Interleukin-1 (IL-1) has been implicated in the development and progression of a variety of acute and chronic inflammatory diseases. Due to its pro-inflammatory and tissue-degrading activities, IL-1 is regarded as a major mediator of chronic inflammatory joint diseases, including rheumatoid arthritis in man, adjuvant arthritis in rats and collagen-induced arthritis in mice. However, conclusive experimental evidence for the crucial role of IL-1 in the development of joint destruction has not been presented as yet. In the present study, we investigated the effect of a neutralizing monoclonal mouse antibody against mouse IL-1 beta (IgG1 isotype) on the development and progression of collagen-induced arthritis in DBA/1 mice. The antibody was injected intraperitoneally 3 times a week, either from day 3 or from day 21 after primary immunization, to day 60. In the positive control group an arthritis incidence of 80% was observed after 60 days. The injection of a control antibody of the same isotype did not influence the incidence of arthritis, whereas injection of anti-IL-1 beta from day 21 reduced the arthritis incidence to about 30%. Injection of anti-IL-1 beta starting at day 3 totally prevented both the development of arthritis and the associated increase of the acute phase protein serum amyloid P (SAP). Anti-collagen antibody titers, which increased significantly after immunization, were not influenced by the injection of anti-IL-1 beta antibodies, in spite of the suppressive effect on arthritis development.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute-Phase Reaction↗