Worm Breeder's Gazette 9(2): 104

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Action Spectra and Absence of Photoreactivation in C. elegans

C. Keller, J. Calkins, P. Hartman, and C.S. Rupert

Action spectra for UV radiation inactivation of reproduction in C.  
elegans have been obtained for N2 and rad-3.  Larvae were irradiated 
and tested individually for their abilities to reproduce.  Use of a 
tunable dye laser radiation source permitted more detail (14 
wavelengths between 254nm and 320nm) than available in the spectra for 
other multicellular organisms.  Overall sensitivity of N2 was similar 
to that of wild-type Escherichia coli; that of rad-3 was 30-fold 
higher between 265nm and 310nm, but its relative sensitivity increased 
below 265nm and decreased above 310nm.
Photoreactivation is a DNA repair process in which pyrimidine dimers 
are enzymatically split in situ.  The capacity to photoreactivate UV 
radiation-induced damage in C.  elegans was tested in two ways.  First,
animals were exposed to a series of fluences at either 254nm or 313nm 
and survival was scored with and without subsequent exposure to 
photoreactivating light.  Animals in a variety of developmental stages 
were tested, including embryos, L1's, L3's and adults.  Second, cell 
extracts were tested for their abilities to produce photoreactivation 
of UV radiation-inactivated bacterial transforming DNA in vitro.  
Photoreactivation was not detected in either set of experiments.  C.  
elegans thus joins the rather limited list of organisms which lack 
this capacity.