John M. Sternfeld, Professor

University of California at San Diego, B.S.
Princeton University, Ph.D.

• Principles of Biology I
• Methods in Laboratory Biology
• Cell Biology
• Developmental Biology

The work in my lab is concerned with developmental aspects of the cellular slime mold, Dictyostelium. At one point in its life cycle this organism consists of single amoeboid cells feeding on bacteria. When the food source is exhausted the cells seek each other out and form a multicellular mass consisting of only a few cell types. The proportion and position of the cell types is precisely controlled as the cell mass, called a slug, migrates across the substrate. Depending on the environmental conditions, the slug can migrate for days or stop and form a fruiting structure with spores on top of a slender stalk. The spores then can germinate into amoebae to start the life cycle again.

Over the last year, some students and I have been looking into some very different aspects of Dictyostelium growth and development. For instance, we have begun an examination of conditions that affect the movement of the organism in its natural habitat of soil. Other students have been trying to determine the cause of rather regularly spaced marks left by the slug as it migrates. My major focus has been on the mechanism of elevation of the spores up the stalk. The spores are not motile themselves, yet they move up the stalk as the fruiting body forms.

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