In response to Tim Wakefield, who wrote: I am looking for some advice on lectin protocols. I am currently binding a FITC-conjugated lectin to the symbiosome membrane surrounding an endosymbiotic algal cell that has been extracted from the anemone host cell. I have had good success in binding the lectins to the membrane, but have had NO success in inhibiting the binding through the use of a competing sugar. According to published literature, the addition of a competing sugar to the lectin solution prior to the addition of the algal cells should prohibit binding to the membrane. Well, it just isn't happening. I have tried varying the concentration of lectin and sugar and this does not seem to have an effect. The lectin that I am currently working with is succinylated-Concanavalin A and it's competing sugar, mannose. A very potent inhibitor of Con-A (not succinylated) is alpha manno-pyranoside and worked just fine at a concentration of 0.1M sugar to 10-50 g/ml Con A when incubatedtogether for 30 min before application. Sometimes incubation time is the problem. Con A has been known to bind by ionic mechanisms also and then the sugar wouldn't work - but I don't know if that would happen with s-Con A. - lots of luck. Libby Gretz Univ. of Virginia [log in to unmask]