Meeting Abstract

73.8  Sunday, Jan. 6  Effects of Long-term Calorie Restriction of the Host on Establishment, Survival and Resistance to Oxidative Stress of the Intestinal Nematode Heligmosomoides bakeri KRISTAN, Deborah M.*; ACOSTA, Wendy; California State University San Marcos dkristan@csusm.edu

Long-term calorie restriction (CR) has many physiological benefits, including enhanced immune function. Despite immune benefits, long-term CR increases susceptibility of laboratory mice (Mus musculus) to Heligmosomoides bakeri. It was not known if increased worm burden was due to increased establishment of larvae or to better adult worm survival. Further, because CR affects production of reactive oxygen species (ROS) by the host which are used against the parasites, we examined H. bakeri susceptibility to ROS. Mice were either given 40% CR or were fed ad libitum (AL) for 5 months, and then were infected with H. bakeri. Fourth stage larvae or adult worms were counted on day 6 or 24 post-inoculation, respectively. Establishment of larvae did not change with host CR, but CR mice had 37% more adult worms than AL hosts. On the day of dissection, 20 male and 20 female worms per host were placed in individual wells of a 48-well plate that contained either control media or 1mM hydrogen peroxide (H₂O₂) media. H. bakeri motility was assessed to indicate worm resistance to H₂O₂. Motility of larvae was not affected by host CR, but decreased with H₂O₂ exposure where male larvae were more susceptibility than female larvae. Adult males also were more susceptible than adult females to H₂O₂ and motility of all adults decreased with H₂O₂ exposure. In contrast to larvae, adult worms from CR hosts were more resistant to H₂O₂ than adult worms from AL hosts. Enhanced adult worm resistance to H₂O₂ when living in a CR host may partially explain why CR hosts harbor more H. bakeri adults than AL hosts even though host CR did not affect larval establishment.