Mark R. Adelman, Ph.D.
Associate Professor of Anatomy, Physiology & Genetics
Uniformed Services University of the Health Sciences
Although I've worked on other subjects (see my CV if you are interested), most of my research has been focussed on trying to understand how cells move. And my favorite system for studies of motility has been, and remains, the acellular slime mold,
Physarum Polycephalum. If you aren't already familiar with this wonderful organism, please take a moment to check out our Website!
As stated, my primary interest in Physarum is related to the astonishing range of motile behaviors that it manifests at different points in its life cycle. Early in my career, drawn by the rapid and oscillatory protoplasmic streaming that occurs in the striking "veins" of hungry plasmodia, I engaged in the isolation and characterization of plasmodial actin and myosin. My studies and those of others in the 1960's and 70's demonstrated that such proteins, previously presumed to be expressed only in muscle cells, were definitely present in Physarum, and - as shown by many other labs - in a wide range of non-muscle cells of "higher" organisms, as well as in various protozoa and other single-celled organisms. In the intervening decades such terms as "non-muscle actin and myosin" have come into, and passed out of, vogue as it has become obvious that essentially all eucaryotes contain the genomic information coding for such proteins and indeed are likely to express them under a variety of situations.
More recently my studies of motility in Physarum have focussed on the amoeboid gametes and their fascinating ability to undergo the so-called amoeboflagellate transformation. I have been especially interested in the actin/myosin of the myxamoebae, the tubulin/dynein of the myxoflagellates, and what happens to the two "opposite" sets of proteins during the rapid and reversible RAFT (Repeat Amoeboflagellate Transformation).
This section is still under construction, but - for now - I include here links to three sorts of images resulting from my studies: the first showing the distribution of actin and tubulin in an amoeboflagellate cell as revealed by double-label fluorescence microscopy, the second showing the three-dimensional distribution of actin in such a cell, revealed by confocal microscopy coupled to three dimensional reconstruction, and the third, a series brief video clips showing various stages of amoeboflagellates undergoing the RAFT in real time.
Most recently, intrigued by the possibility of using "traditional" histological stains as fluorescent probes in confocal microscopy, I have captured some interesting images of the nuclei in shake-cultured microplasmodia, labelled with Nuclear Fast Red, and again displayed by three dimensional reconstruction.
Last modified:Friday, December 5, 2003