[
European Worm Meeting,
2002]
Transformation of the worm by microinjection is now a rate-limiting step in many labs during the analysis of genes. We find microinjection still quite unreliable and cumbersome. At least in our hands the transformation rate is in average quite low, we get only one stable array per 30 injected hermaphrodites. In 1999 we demonstrated that the worm can be reliably transformed using ballistic bombardment with gold particles using a helium gun. However, the efficiency by which stable arrays were formed was still rather low, approximately one stable line per ten shots was isolated. Meanwhile we improved the method by a factor of 100; typically we now isolate 10 stable arrays per shot. One or two of these lines show a stable transmission of the transformed DNA, indicating that integration into the genome occurred. The in and outs of biolistic transformation will be discussed.
Punjabi, Nihal, Yardley, Reule, Bhagawat, Chaiti, Lee, Diane, Nguyen, Tiffany, Carmona, Javier, Kardoust, Arash, Mohnot, Kushal, Santana, Joslyn, Mendoza, Steve, Rabichow, Laura, McAdam, Meera, Fu, Daniel, Ross, Evan, Mahavni, Anika, Arisaka, Katsushi
[
International Worm Meeting,
2017]
Self-awareness is a critical aspect related to the effective navigation of a complex environment. For a given input stimulus to a sensory structure, behavioral output seems closely related to an organism's own motion. An example may be drawn from a relativistic pressure applied to a C. elegans' mechanosensory structure in time, based on two conditions. When considering a mechanical pressure driven by the worm's own motion (as if a worm struck a stationary barrier) the response is dramatically different to one of similar magnitude unrelated to the worm's motion (if a stationary worm was lightly touched with an eyebrow hair). Interestingly, these conditions apply the same force to a given sensory structure in time, but result in a much higher probability of avoidance response if the worm is stationary at the time of the input. To more closely evaluate this complex phenomenon, the well characterized, highly deterministic photo-avoidance behavior was implemented in a number of experimental wave speed conditions. We postulate that a lower avoidance response probability will be found in quickly moving C. elegans as compared to those with slow wave speeds. Gelatin concentration was altered from 1 - 4 % in order to shift the wave speed accordingly, while phototaxis stimulation acted as our input force; provided from a well-calibrated 405nm laser. A custom-built line confocal microscope supplied a triggering signal to the laser stimulus while recording worm position and orientation over experimental trials. Offline, a MatLab program was used to analyze the data and sinusoidally fit an analytic function to the worm's body in time. Wave speed and center of mass velocity were extracted from this data, and avoidance probability was investigated as an independent variable. Preliminarily, observations suggest that lower gelatin concentrations (i.e. faster wave speed) correspond with lower avoidance probability; perhaps due to a partial inhibition of the AVA interneuron through sensorimotor integration.