Identification of receptors for bacterial lectins by blotting techniques

This chapter discusses the identification of receptors for bacterial lectins by blotting techniques. Because of the phenomenon of phase variation in the production of adhesins, however, the bacteria must be grown under conditions that are optimal for phenotypic expression of the adhesin. Also, for application to nitrocellulose strips, the bacteria must be suspended in a buffer that is optimal for adhesin activity. The latter can be determined by testing the ability of the bacteria to adhere to suitable target cells. Autoradiography is the most sensitive means to detect the receptors on the blots. Exposures can be repeated until optimal signals are obtained. However, the resolution of enzyme-linked assays appears to be superior to that of autoradiography. Whenever possible, the specificity of the binding should be ascertained. In the case of the bacterial surface lectins, this is readily done by establishing whether binding of the probe to the blotted glycoproteins is inhibited by the mono- or oligosaccharides for which the bacteria are specific. Another way is to test the effect of treatment of blots in situ with carbohydrate modifying reagents, such as glycosidases or periodate.