Imaging of Caenorhabditis elegans neurons by second-harmonic generation and two-photon excitation fluorescence

Second-harmonic generation (SHG) and two-photon exci- tation fluorescence (TPEF) are relatively new and promising tools for the detailed imaging of biological samples and processes at the mi- croscopic level. By exploiting these nonlinear phenomena phototox- icity and photobleaching effects on the specimens are reduced dra- matically. The main target of this work was the development of a compact inexpensive and reliable experimental apparatus for nonlin- ear microscopy measurements. Femtosecond laser pulses were uti- lized for excitation. We achieved high-resolution imaging and map- ping of Caenorhabditis elegans (C. elegans) neurons and muscular structures of the pharynx, at the microscopic level by performing SHG and TPEF measurements. By detecting nonlinear phenomena such as SHG and TPEF it is feasible to extract valuable information concerning the structure and the function of nematode neurons. © 2005 Society of