Eylem Seç
The affinity of staphylococcal alpha-lysin (alpha-toxin) for erythrocytes
Başlık:
The affinity of staphylococcal alpha-lysin (alpha-toxin) for erythrocytes
Yazar:
Phimister, Graeme M., author.
ISBN:
9780438057302
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (224 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Advisors: J. H. Freer.
Özet:
Alpha-lysin was prepared from the culture supernatant fluid of Staphylococcus aureus Wood 46, by ammonium sulphate precipitation, chromatography on controlled-pore glass and electrofocusing in an LKB 110 ml electrofocusing column pH 6.5-12, in a sorbitol density gradient. Alpha-lysin focused with a pI of 8.5 and had a specific haemolytic activity of 104 MHD/mg in agreement with published data. Contamination of the purified alpha-lysin by beta-lysin was estimated at <0.015% (w/w), by delta-lysin at <0.7% (w/w) and by protease at <0.06% (w/w). The purified a-lysin gave a single line in immunodiffusion tests against serum containing antibodies to a wide spectrum of staphylococcal extracellular products. When high amounts of protein were applied to the gel, minor contaminants were detectable in the purified lysin by sodium dodecyl sulphate polyacrylamide gel electrophoresis. The molecular weight was estimated to be 34,000 daltons, by sodium dodecyl sulphate polyacrylamide gel electrophoresis, a figure in agreement with published data. Only the purified alpha-lysin, and not any minor contaminants were iodinated by the lactoperoxidase method. The iodinated alpha-lysin retained full haemolytic activity. This preparation was used to study factors affecting binding to fixed and unfixed rabbit and horse erythrocytes. A relatively constant percentage of the added lysin bound to both cell types, although more lysin was bound per rabbit erythrocyte than per horse erythrocyte. More lysin bound to fixed cells than to unfixed cells. The percentage of added lysin that bound to red blood cells was independent of temperature, pH, cell and lysin concentration. Neither native lysin nor concanavalin A competed with 125I-labelled alpha-lysin in binding to erythrocytes. Zinc ions, which inhibit haemolysis of erythrocytes by alpha-lysin, increased binding of the lysine to erythrocytes. These effects were reversed by L-histidine. No saturation of rabbit erythrocyte binding sites was evident using lysin concentrations which gave up to 6 x 10e6 molecules of lysin bound per cell. Native lysin bound to unfixed rabbit cells at both 37°C and 4°C, but no haemolysis was evident below 16-18°C. Above this temperature range, lysis increased rapidly to 100%, with increasing temperature. The release of sequestered glucose by alpha-lysin from liposomes prepared from rabbit and horse erythrocyte lipids was studied. Twice as much glucose was released from rabbit lipid liposomes as from horse lipid liposomes by the same concentration of lysin. The rate of release from rabbit lipid liposomes was twice as fast as from horse lipid liposomes. The amount of glucose released from rabbit lipid liposomes was the same at 37°C and 4°C while glucose was only released from horse lipid liposomes at 37°C. These investigations indicate that alpha-lysin can bind to natural and artificial membranes via a relatively non-specific mechanism. The absence of highly specific binding sites in sensitive cells suggest that differences in sensitivity to alpha-lysin depends upon post-binding events in the membrane, rather than differences in the affinity of cell surfaces for the lysin.
Notlar:
School code: 0547
Konu Başlığı:
Tüzel Kişi Ek Girişi:
Mevcut:*
Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(684589.1) | 684589-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
On Order
Liste seç
Bunu varsayılan liste yap.
Öğeler başarıyla eklendi
Öğeler eklenirken hata oldu. Lütfen tekrar deneyiniz.
:
Select An Item
Data usage warning: You will receive one text message for each title you selected.
Standard text messaging rates apply.