Affinity chromatography purification of Clostridium perfringens enterotoxin

Scaled-up production and purification of Clostridium perfringens type A enterotoxin

Methods for small-scale production of Clostridium perfringens type A enterotoxin were unsuitable for large-scale culture of this organism. Rapid, efficient harvesting of 40 1 batch culture of Cl. perfringens was achieved by tangential flow micro-filtration with the Millipore Pellicon cassette system. Enterotoxin-containing extracts were prepared by passing concentrated suspensions of the harvested cells through a French pressure cell. The overall yield of purified enterotoxin was 38.8%. The toxin gave a single band on native polyacrylamide gels but formed high molecular weight aggregates in the presence of sodium dodecyl sulphate. These aggregates frequently occurred during storage of non-sterile enterotoxin preparations but could be separated from the monomer toxin by gel filtration on Sephadex G-100. Purified monomer enterotoxin had biological activities of 119.3 micrograms/kg mouse lethal dose when injected intraperitoneally and 3333 capillary permeability increasing units/mg protein in guinea pig skin. Thirty micrograms of the enterotoxin caused fluid accumulation in ligated rabbit ileal loops. Aggregated enterotoxin had no demonstrable biological or immunological activity.

Purification by high performance liquid chromatography of Clostridium perfringens type A enterotoxin prepared from high toxin producers selected by a toxin-antitoxin halo

High enterotoxin-producing substrains of Clostridium perfringens type A were selected reproducibly as colonies having toxin-antitoxin haloes on agar plates of Duncan-Strong medium containing antitoxin serum. Enterotoxin from these substrains was subjected to rapid purification by high performance liquid chromatography (HPLC). For this, the toxin was extracted by sonication from sporulating bacteria grown in Duncan-Strong sporulation medium, fractionated by ammonium sulfate (40% saturation) precipitation and differential solubilization and then purified by HPLC: gel permeation chromatography through a G2000SW column and ion-exchange chromatography on a Mono Q column. Purified toxin preparations had a similar specific activity (4.2 X 10(2) mouse MLD/mg protein) and homogeneity on polyacrylamide gel-electrophoresis to preparations obtained by conventional gel permeation through a Sephadex-G200 column. By further HPLC on a Mono Q column, minor nontoxin proteins were separated from the toxin without loss of the toxicity on a protein basis. The final yield of the purified toxin was about 15% of that in the bacterial extract. The two HPLC procedures each took only one hour.

Preparative polyacrylamide gel electrophoresis purification of Clostridium perfringens enterotoxin

Preparative polyacrylamide gel electrophoresis has been used to purify the enterotoxin of Clostridium perfringens from Sephadex G-100 extracts. Purified toxin of high specific activity was eluted in 1 to 3 h, depending upon the length of the acrylamide gel used. Recovery of biological activity with this technique ranged from 80 to 90%. The purity and physical characteristics of the toxin were similar to those previously reported for the protein purified by other methods. Use of preparative electrophoresis will enable the production of larger amounts of high-specific-activity toxin in a shorter time than other currently available procedures. This method was also used to isolate a form of enterotoxin that has a mobility, relative to bromophenol blue tracking dye, of 0.87 to 0.90 in 7% acrylamide gels.

Evidence for stable messenger ribonucleic acid during sporulation and enterotoxin synthesis by Clostridium perfringens type A

Stable messenger ribonucleic acid (mRNA) was shown to be involved in both enterotoxin synthesis and synthesis of other spore coat proteins in Clostridium perfringens. When used at a concentration that inhibited [14C]uracil incorporation, rifampin, a specific inhibitor of deoxyribonucleic acid-dependent RNA polymerase, prevented incorporation of a mixture of labeled amnoo acids by 3-h sporulating cells. At that time, enterotoxin protein was first detectable and cells were primarily at stage II or III of sporulation. When rifampin or streptolydigin was added to 5-h sporulating cells, which were primarily at stage IV or V and had significant toxin levels, incorporation of labeled amino acids continued through 30 min despite its presence. Rifampin also failed to prevent the specific synthesis of enterotoxin, a structural protein of the spore coat. The half-life of enterotoxin RNA was estimated to be at least 58 min. When cell extracts from 5-h sporulating cells that had been exposed to 3H-labeled amino acids for 10 min were subjected to electrophoresis on polyacrylamide gels and the gels were subsequently analyzed for radioactivity, two major peaks of radioactivity were obtained. The two peaks corresponded to enterotoxin and another spore coat protein(s). Similar results were obtained when the cells had been preincubated for 60 min with rifampin before label addition, indicating the functioning of stable mRNA.

An enterotoxin produced by Clostridium perfringens type D. Purification by affinity chromatography

Clostridium perfringens type D 9867 produced enterotoxin immunologically identical to that produced by types A and C which are responsible for C. perfringens food poisoning. Enterotoxin from type C 5386 and type D 9867 was produced in Duncan og Strong sporulation medium (DS medium). The supernatant fluid from DS-cultures was used for purification of the enterotoxin by affinity chromatography on a monospecific anti-enterotoxin-coupled CNBr activated-Sepharose 4B and activated CH-Sepharose 4B column. The enterotoxin purified by this one-step procedure proved to be of a purity comparable to that obtained by conventional methods, and possessed lethal activity in mice.