There are some microbes especially gurmicrobiota that perform different functions from food digestion to defence against pathogenic bacteria. They also produce some enzymes, antimicrobial peptides etc.
Dear Khalid, Can you please elaborate on your question a bit more. What kind of data do you have? Or is it just one protein that you are interested in.
I am planning to work on local honey bee races Apis mellifera jemenitica. These bees are more resistant to high temperature and drought conditions here in kingdom of Saudi Arabia as compared to imported bees(Apis mellifera carnica). There is possibility that some exogenous protein may be responsible for these resistance. Therefore i need some detailed procedure how to differentiate extra-cellular proteins.