The Effects of Cranberry Consumption on Lipid and Lipoprotein Metabolism in Human Apolipoprotein A-I Transgenic Mice Fed a High Fat and High Cholesterol Diet
Investigators: Christian Caceres, Dr. Ji-Young Lee, Dr. Young-Ki Park
The development of pathological conditions including cardiovascular disease are well documented to manifest from an obese state due to high lipid burden at adipose tissue and consequent low-grade inflammation. We hypothesized that anthocyanin-rich whole cranberry powder would prevent inflammation while simultaneously modifying high- density lipoprotein (HDL) metabolism to confer cardioprotection in C57BL/6J mice expressing human apolipoprotein A-I transgene (hApoAITg). Male hApoAITg C57BL/6J mice were fed a modified AIN-93M high fat/high cholesterol diet (HF/HC; 15% fat, 0.25% cholesterol by weight) with only the treatment group receiving 5% whole cranberry powder by weight for 8 weeks. Our results suggest that CR supplementation decreases obesity-induced inflammation in adipose tissue at least in part, by modulating energy metabolism in skeletal muscle. However, additional investigations are required to conclusively determine the effect of cranberry consumption on serum lipids and HDL metabolism.
Tyrosine Phosphorylation of the Bacterial Stress Factor BipA aids in Adaptation and Pathogenicity
Investigators: Akua Owusu and Jui Chaugule
Faculty Advisors: Dr Victoria Robinson and Dr David Benson
BipA is a multi-domain prokaryotic GTPase universally conserved in pathogenic bacteria. It regulates a number of virulence events including pedestal formation, flagella mediated motility and expression of virulence genes. Most importantly, BipA null mutants are avirulent, suggesting it is a prime target for antimicrobial development. Central to the function of BipA are its GTPase activity and its association with the ribosome. An examination of the ribosome binding properties of the protein revealed that BipA has two ribosome binding modes. Under normal growth conditions, GTP-bound BipA associates with 70S ribosomes. However, under conditions of stress, ppGpp-bound BipA associates with 30S ribosomes. A study by the O’Connor group at the University of Southampton (UK) demonstrated that BipA undergoes phosphorylation on one of its tyrosine residues and perhaps this modification may play a role in its ability to regulate virulence processes. Therefore, the purpose of my project was to identify the tyrosine phosphorylation sites in EHEC BipA and then determine how this modification affects its biochemical properties particularly its GTPase activity.