PT  - JOURNAL ARTICLE
AU  - Takaaki Bamba
AU  - Rakan Matsui
AU  - Kazuo Watabe
TI  - Effect of Steam-Heat Treatment with/without Divalent Cations on the Inactivation of Lipopolysaccharides from Several Bacterial Species
DP  - 1996 Mar 01
TA  - PDA Journal of Pharmaceutical Science and Technology
PG  - 129--135
VI  - 50
IP  - 2
4099  - http://journal.pda.org/content/50/2/129.short
4100  - http://journal.pda.org/content/50/2/129.full
SO  - PDA J Pharm Sci Technol1996 Mar 01; 50
AB  - The inactivation of endotoxin from six species of smooth gram-negative bacteria (S-form) by steam-heat treatment was investigated using the Limulus amebocyte lysate (LAL) assay. Biphasic decreases of endotoxins from four species of bacteria were observed upon steam-heat treatment of 1 µg/ml endotoxin solution at 121°C in a steam sterilizer. A lag time, however, was observed in the inactivation profiles of V. cholerae and P. aeruginosa. Distinct differences in heat resistance were observed among the bacterial species. The decrease rate was found to be concentration-dependent, and endotoxins at low concentrations (less than 10 ng/ml) were inactivated by the treatment to below the detection limit of the LAL assay. The time-course of the decrease of endotoxin from rough strains (R-form) resembled that of the respective S-form. The inactivation of R-form, especially Rc mutant, endotoxin was markedly affected by divalent cations such as Mg2+ and Ca2+, which appear to promote reaggregation of the endotoxin.