Double-sandwich enzyme-linked immunosorbent assay for determination of Escherichia coli heat-labile porcine enterotoxins.

A "double-sandwich" ELISA for the detection and measurement of a heat-labile enterotoxin produced by porcine enterotoxigenic strains of Escherichia coli (LTp) is described. In contrast with other heat-labile toxins, LTp did not bind to agarose gels and exhibited a very low affinity for GM1 in the classical GM1-ELISA technique. The similarity of LTp with cholera toxin was confirmed by immunoblotting.

Influence of major minerals on rumen microbiota.

The supply of minerals needed to meet rumen microbe requirements should match the amount of energy available for fermentation. Therefore, we attempt to assess microbial requirements for phosphorus (P), sulfur (S) and magnesium (Mg) in terms of fermentable organic matter at the rumen level (OMF) or in terms of digestible matter in the total tract (OMD). In vivo, about 5 g of P and 1.

Na-Stimulated Transport of l-Methionine in Brevibacterium linens CNRZ 918.

The transport of l-methionine by the gram-positive species Brevibacterium linens CNRZ 918 is described. The one transport system (K(m) = 55 muM) found is constitutive for l-methionine, stereospecific, and pH and temperature dependent. Entry of l-methionine into cells is controlled by the internal methionine pool.