Synapses at last.

Finally, after years of tedious work, we have our first very high quality thin section series through synapses in Pristionchus pacificus. This image is of the nerve ring in the pharynx, which controls many aspects of feeding behavior in the nematode and is like a mini-brain. It is very difficult to obtain such data and few groups have done it, so this is no small victory for me. We have a long way to go though, as the “real” brain of the animal is still hundreds of sections away, but if things continue to go well we could finish this in January or early February. The triangular white structure you see in the middle is the lumen of the pharynx, through which all of the food passes. In fact, there is rather conveniently a bacteria in the center in the process of being swallowed by the worm. Clusters of black spheres in the smaller cells are synaptic vesicles, and the black blotches on the cell membrane adjacent to the synaptic vesicles are pre-synaptic densities.. on the other side of each synaptic density is the cell each neuron is “talking” to. The two irregularly shaped holes near the pharynx lumen are gland cell ducts, that fuse with the lumen a few microns from this image and likely secrete digestive enzymes. Filamentous structures radiating out from the lumen are muscle cell filaments, used to open and close the lumen. Beautiful, isn’t it?