Dialysis And Ultrafiltration Of A Heat-Stable Enterotoxin From Escherichia Coli

Effect of Klebsiella pneumoniae enterotoxin on intestinal transport in the rat.

“…Subsequent purification procedures, employing Sephadex column chromatography, have yielded a fraction of this material that induces net water secretion in the rat jejunum at a dosage of 0.5 jug/ml.2 Klebsiella enterotoxin bears a number of resemblances to E. coli ST. Both are heat-stable and, in contrast to other enterotoxins (6), have a low molecular weight (5,39), ST prepared by the same process and used in a similar dosage as in the present study evokes net water secretion in the ileum of calves (40). Whereas the effect of choleragen and E. coli LT on intestinal transport is not evident for several hours (26,41), Klebsiella toxin and ST act promptly.…”

Separation and Purification of Enterotoxins From a Strain Escherichia Coli Pathogenic for Pigs

“…The high-MW toxin produced in our studies had a MW slightly lower than that found by Larivikre (1971) and Jacks et al (1973) whilst our low-MW toxin was very similar to that found by Kohler (1971), especially if the weight of 333 suggested by ultraviolet absorbence was correct. Likewise our medium-MW toxins had weights within the range stated by Bywater (1972), viz., 104-103. One of our toxins had a MW of 9.5 x 103 yet would not pass a PM.10 membrane, but it should be pointed out that the MW was only just below that excluded by this type of filter.…”

“…Some investigators (Larivikre, 1971 ;Jacks et al, 1973) have suggested that most enterotoxic activity is associated with a MW of about 106, whilst others (Kohler, 1968(Kohler, , 1971bSmith and Gyles, 1970a) have stated that only low-MW toxin is found in culture supernates; Kohler (1971b) has presented data that suggest that the MW is just below that of sucrose. Bywater (1972), using a pathogenic strain of E. coli from a calf, suggested that there was no high-MW toxin but that most of the activity was associated with MW values within the range 104-103, and only a little with values of < 103. However, his results showed some increase in activity in the PM.10 retentate which might have been caused by high-MW toxin; furthermore, some high-MW activity might have been lost during precipitation by acetone, a solvent which in our experience (unpublished observation) has resulted in poor recovery of activity.…”

“…Enterotoxins that are more accurately defined and of greater purity are needed so that (1) results obtained by workers in different laboratories can be properly compared (2) the importance of enterotoxin in scouring can be further elucidated, and (3) the development of a method of assay more reliable than that made in ligated segments of intestine may be facilitated. Attempts to concentrate and purify enterotoxins produced in culture supernates by pathogenic E. coli have given contradictory results (Kohler, 1968(Kohler, , 1971b; Smith and Gyles, 1970a;Larivikre, 1971 ;Bywater, 1972;Jacks et al, 1973). This may be because different enterotoxins are produced by different strains (Truszczynski and Ciosek, 1972) or because a single strain may produce enterotoxins with a variety of molecular weights; a further possibility is that the method of culture influences which of the various enterotoxic components predominates.…”

Conditions for the Production of Escherichia Coli Enterotoxin in a Defined Medium

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CONFUSION exists about the chemical and physico-chemical characteristics of enterotoxins produced in culture supernates by strains of Escherichia coli pathogenic for pigs and reported upon by Smith and Halls (1967), Kohler (1968), Larivi6re (1971), andBywater (1972). We considered that some of the apparent anomalies might be attributed to the presence of peptides and polypeptides in the media used for bacterial growth, namely " syncase " medium (Finkelstein, Norris and Dutta, 1964;Kohler, 1968) and semisolid nutrient agar (Smith and Halls, 1967).

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