COATS FROM MYXOCOCCUS XANTHUS: CHARACTERIZATION AND SYNTHESIS DURING MYXOSPORE DIFFERENTIATION

Abstract

An extracellular coat from glycerol-induced myxospore of Myxococcus xanthus has been isolated and characterized. Coats were examined chemically and using both transmission and scanning electron microscopy. On a dry weight basis, approximately 75 % of the coat is polysaccharide composed entirely of galactosamine and glucose. The reminder of the coat is protein (14 %), glycine (8 %) and organic phosphorus (less than 1 %). Coats remained morphologically intact despite boiling in 10 M urea, sodium lauryl sulfate plus B-mercaptoethanol, or extraction with warm phenol. Coats also resisted digestion with a variety of proteolytic and polysaccharide degrading enzymes. Synthesis of myxospore coat begins approximately 1 hour after the addition of glycerol to a culture. One portion of the coat is complete by 5 - 6 hours but additional material consisting primarily of glucose is added after 8 hours.