Ultrastructure of <i>tba-1(ju89)</i> Motor Neuron Synapses.

<p>The ultrastructure of one adult wild-type and two <i>ju89</i> adult mutant worm were examined by EM (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009655#s4" target="_blank">Methods</a>). 1500 continuous sections of 50 nm each were collected from 1 wild-type adult animal and 400 sections from each of two <i>ju89</i> adult mutant worms. Sections were collected in the anterior of each animal between the nerve ring and the vulva. Inhibitory GABAergic motor neurons form synapses directly onto dorsal and ventral muscles; excitatory cholinergic motor neurons form dyadic synapses with muscles and a GABAergic motor neuron dendrite. Representative GABAergic motor neuron synapses with body wall muscle arms in (A) wild-type and (C) mutant <i>tba-1(ju89)</i> animals, and cholinergic motor neuron synapses in (B) wild-type and (D) <i>ju89</i> worms. Fewer synaptic vesicles are visible in both types of synapses in the mutants. (E) The number of synaptic vesicles per active zone (p<.05), (F) length of the active zone in nm (p<.05), and (G) number of synaptic vesicles/active zone length for the cholinergic motor neuron synapses in one animal are shown. Cholinergic synapse size is reduced in the <i>ju89</i> mutant. Error bars: S.E.M.