Nathan C. Stewart

Learn More
We conducted a large-scale gene expression screen using the 3,200 cDNA probe microarray developed specifically for Ursus americanus to detect expression differences in liver and skeletal muscle that occur during winter hibernation compared with animals sampled during summer. The expression of 12 genes, including RNA binding protein motif 3 (Rbm3), that are(More)
Hibernation is an adaptive strategy to survive in highly seasonal or unpredictable environments. The molecular and genetic basis of hibernation physiology in mammals has only recently been studied using large scale genomic approaches. We analyzed gene expression in the American black bear, Ursus americanus, using a custom 12,800 cDNA probe microarray to(More)
Resumen.—La molécula de hemoglobina juega un papel clave en el transporte de oxígeno. Hemoglobinas con gran afinidad por el oxígeno son adaptativas en ambientes hipóxicos. Para ampliar nuestro conocimiento acerca de la adaptación a la hipoxia de altura, se extrajo ARN de la médula ósea de seis espécimenes de Lophonetta specularioides de los Andes centrales(More)
Species of the bear family (Ursidae) are important organisms for research in molecular evolution, comparative physiology and conservation biology, but relatively little genetic sequence information is available for this group. Here we report the development and analyses of the first large scale Expressed Sequence Tag (EST) resource for the American black(More)
Physical inactivity reduces mechanical load on the skeleton, which leads to losses of bone mass and strength in non-hibernating mammalian species. Although bears are largely inactive during hibernation, they show no loss in bone mass and strength. To obtain insight into molecular mechanisms preventing disuse bone loss, we conducted a large-scale screen of(More)
Vadim B. Fedorov, Anna V. Goropashnaya, Øivind Tøien, Nathan C. Stewart, Andrew Y. Gracey, Celia Chang, Shizhen Qin, Geo Pertea, John Quackenbush, Louise C. Showe, Michael K. Showe, Bert B. Boyer, and Brian M. Barnes Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska; University of Southern California, Los Angeles, California;(More)
Hibernation is an energy-saving adaptation that involves a profound suppression of physical activity that can continue for 6-8 months in highly seasonal environments. While immobility and disuse generate muscle loss in most mammalian species, in contrast, hibernating bears and ground squirrels demonstrate limited muscle atrophy over the prolonged periods of(More)
  • 1