Bioenergetics Research Projects:

Based on a review of the literature, there have never been functional chloroplasts isolated from any ferns. Studies of fern chloroplasts in situ indicate that fern chloroplasts have some unique properties. They are readily and rapidly moved about and reoriented within the cell, by a process that is energy dependent and evidence indicates that actin and a "myosin-like" molecule are involved. Most of the attempts that we have made thus far to prepare isolated chloroplasts from fern have lead to an aggregated mass rather than a suspension of individual chloroplasts. Our hypothesis has been that residual actin is binding the chloroplasts together and we have attempted to change the solutions and conditions to break this bonding. Some non- aggregated chloroplast suspensions have been obtained, but they have not shown the expected electron transport activity. The goal is to find conditions that will allow isolation of good chloroplasts and then to study light-dependent reactions and energetics in those chloroplasts.

Research suggestions:

1. A priority is to isolate chloroplasts capable of photophosphorylation from ferns. Some of the questions that remain are: What is the best way to open the cells and release the chloroplasts without damaging the chloroplasts? Can we establish the appropriate conditions to measure electron transport (Hill reaction activity) by oxygen evolution, reduction of acceptors, partial reactions, etc? What are the effects of inhibitors and reaction conditions? There are a lot of fairly easy parallels that can be made to the existing information on spinach chloroplasts.
2. Characterization of ATPases from ferns. There must be at least several different ATPases present. Mitochondrial and chloroplast ATPase of the classical five subunit kind will undoubtedly be present and could be isolated and characterized. The sequence homology of the DNA for the subunits, and whether the peptides have a nuclear or cytoplasmic origin could be determined. Various ion-pumping ATPases from fern, comparable to those found in or on the membranes of other plants, could bestudied as well.