Ciliar activity is a dynamic process requiring high speed visualization techniques to study wave form and functional processes. Almost all biological organisms rely on ciliar/flagellar activity in some way. Clams with a complex array of cilia on the gills to intercept particulate matter and direct the food toward the buccal cavity afford one type of model system to study ciliar activities. We have used a combination of traditional light and electron microscopy techniques coupled to data captured from rapid video acquisition from a real time laser confocal microscope to study ciliar waveform, cilia/ particle interaction, and particle transport to better understand the actual interactions that might occur in a realm of rapidly varying Reynold's number. To date we are the only laboratory studying living tissues in real time using these types of techniques to describe complex biological process. fundamental data gathered in this system will ultimately be applicable to such wide ranging biological phenomena as fertilization and cilia/particle interactions in trachea and lungs of mammals.
A second major interest in my laboratory focuses on fertilization events in invertebrate animals. The union of sperm and egg marks a critical event in the life history of sexual organisms. This specific event triggers the developmental process that will produce a new individual. Gametes and gamete interaction can be studied by following many different morphological, biochemical, and physiological events. The very early events of fertilization form the central impetus in my laboratory and are studied using a combination of techniques including electrophysiology, confocal microscopy, ion substitution, and other advanced light and electron microscopy techniques.
The combination of morphological and electrophysiological approaches is used to address questions on gamete interaction including the timing of gamete fusion, ion requirements for successful fertilization in freshwater and marine organisms, and temporal relationships of electrophysiological and morphological events during gamete interaction. The focus in each case is to answer such questions as mechanisms of egg activation, role of the cytoskeleton in sperm entry, pronuclear formation, and positioning of the cleavage furrow, and blocks to extranumerary sperm entry. Research in my lab generally relies on invertebrate model organisms including sea urchins, freshwater mussels, and penaeoid shrimp.
Silverman, H., J.W. Lynn, P.G. Benninger, and T.H. Dietz. 1999. The role of latero-frontal cirri in particle capture by the gills of Mytilus edulis. Biol. Bull. 197:368-376.
Silverman, H., J. W. Lynn and T. H. Dietz. 1999. In vitro studies of particle capture and transport in suspension-feeding bivalves. Limnol. Oceanog. (in press).
Silverman, H., S. J. Nichols, J. S. Cherry, E. Achberger, J. W. Lynn and T. H. Dietz. 1997. Clearance of laboratory–cultured bacteria by freshwater bivalves: Differences between lentic and lotic unionids. Can. J. Zool. 75: 1857–1866.
Silverman, H., J. W. Lynn, and T. H. Dietz. 1996. Particle capture by the gills of Dreissena polymorpha: Structure and function of latero–frontal cirri. Biol. Bull. 191: 42–56.