title: Purified colicin as cytotoxic agent of neoplasia: comparative study with crude colicin.
abstract: Purification of a bacteriocin, colicin, from Escherichia coli HSC10, is described. A 1,800 fold purified colicin was obtained and found to be an acidic polypeptide with a molecular weight of 82,000 daltons. The effect of colicin on bacterial and mammalian cells during the transition from a crude to a pure preparation is given. A turbidimetric assay for bacterial growth inhibition and 3H-thymidine uptake inhibition for measuring the effect on mammalian cells, was used. Colicin HSC10 caused DNA loss from the bacteriocin-sensitive mammalian cells, which increased with dose and time of exposure. Therefore, flow-cytometry, which detects DNA loss from the bacteriocin-affected mammalian cells, was also used to evaluate the bacteriocin potency. Similar quantitative results were obtained to those using 3H-thymidine uptake inhibition, in terms of microgram protein of pure colicin required to affect adversely 50% of the cells. The bacteriocins were found to retain their activity following freezing and thawing, both as crude and pure preparations, against both bacterial and mammalian cells.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D003087:Colicins / Q000032:analysis / Q000302:isolation & purification / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000032:analysis* / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005354:Fibrosarcoma; D005615:Freezing; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008970:Molecular Weight; D013936:Thymidine / Q000378:metabolism
chemical_list: D000596:Amino Acids; D003087:Colicins; D008070:Lipopolysaccharides; D004247:DNA; D013936:Thymidine