Search

Acid soluble basement membrane collagen (ABMC) was prepared by extraction of the anterior lens capsules from bovine calf eyes in 0.5 M acetic acid in the presence of the protease inhibitors leupeptin and pepstatin. Thermal aggregates formed from soluble basement membrane collagen were facilitated by heating (28°C) the collagen solutions in 0.5 M phosphate buffer. The effects of endotoxins derived from Salmonella minnesota R595, Chromobacterium violaceum and Rhodopseudomonas viridis on the assembly at basement membrane collagen were ascertained by analysis of turbidity curves (340 nm) obtained during aggregation in vitro. All of the endotoxins tested were noted to inhibit the final level of turbidity and to prolong the lag period for thermal assembly. Plotting the increase in turbidity against the logarithm of time or analyzing the turbidity curves as first-order reaction indicated that what was altered was the rate of assembly of fibrils in collagen treated with endotoxin, rather than the mechanism of assembly of these fibrils. These conclusions arc supported by Arrhenius plots of basement membrane aggregations in vitro in the presence and absence of endotoxins. [ABSTRACT FROM AUTHOR]