Biology Commons^™

Global Climate Change And The Southern Ocean: How Antarctic Fishes Physiologically Respond To A Changing Environment From The Cellular To The Organismal Level, Laura A. Enzor

Theses and Dissertations

Studies have projected that future changes in sea surface temperature and pCO2 levels will impact higher latitudes to a greater extent than in temperate regions. For notothenioid fishes of the Southern Ocean, evolution in extremely stable, cold waters has resulted in several adaptations which have left these fishes poorly prepared for global climate change. I have analyzed the metabolic and cellular response of Trematomus bernacchii, Pagothenia borchgrevinki and Trematomus newnesi to a long-term, multi-stressor scenario relevant to the predicted changes in the Southern Ocean. By combining whole animal respirometry with cellular level analysis of energy allocation, osmoregulatory mechanisms and cellular …

A Distinct Tethering Step Is Vital For Vacuole Membrane Fusion, Michael Zick, William T. Wickner

Dartmouth Scholarship

Past experiments with reconstituted proteoliposomes, employing assays that infer membrane fusion from fluorescent lipid dequenching, have suggested that vacuolar SNAREs alone suffice to catalyze membrane fusion in vitro. While we could replicate these results, we detected very little fusion with the more rigorous assay of lumenal compartment mixing. Exploring the discrepancies between lipid-dequenching and content-mixing assays, we surprisingly found that the disposition of the fluorescent lipids with respect to SNAREs had a striking effect. Without other proteins, the association of SNAREs in trans causes lipid dequenching that cannot be ascribed to fusion or hemifusion. Tethering of the SNARE-bearing proteoliposomes was …

Increasing Energetic Cost Of Biosynthesis During Growth Makes Refeeding Deleterious, Chen Hou

Biological Sciences Faculty Research & Creative Works

Diet restriction (DR) enhances animals' health maintenance, but refeeding reverses its beneficial effects. However, to what degree refeeding reverses the beneficial effects of DR remains controversial. Here, I develop a theoretical model for reconciling the results of refeeding studies and understanding the dynamic and reversible mechanism underlying the effects of diet on health from the energetic viewpoint. By illustrating the negative correlation between health maintenance and the energetic cost of growth in animals under different diet regimes, the model explains why, in some cases, refed animals have better health and live longer than freely fed controls. More importantly, the model …

New Frontiers For The Nfil3 Bzip Transcription Factor In Cancer, Metabolism And Beyond, Megan Keniry, Robert K. Dearth, Michael W. Persans, Ramon Parsons

Biology Faculty Publications and Presentations

The bZIP transcription factor NFIL3 (Nuclear factor Interleukin 3 regulated, also known as E4 binding protein 4, E4BP4) regulates diverse biological processes from circadian rhythm to cellular viability. Recently, a host of novel roles have been identified for NFIL3 in immunological signal transduction, cancer, aging and metabolism. Elucidating the signaling pathways that are impacted by NFIL3 and the regulatory mechanisms that it targets, inhibits or activates will be critical for developing a clearer picture of its physiological roles in disease and normal processes. This review will discuss the recent advances and emerging issues regarding NFIL3-mediated transcriptional regulation of CEBPb and …

Antimicrobial And Antiinsectan Phenolic Metabolites Of Dalea Searlsiae, Gil Belofsky, Mario Aronica, Eric Foss, Jane Diamond, Felipe Santana, Jacob Darley, Patrick F. Dowd, Christina M. Coleman, Daneel Ferreira

All Faculty Scholarship for the College of the Sciences

Continued interest in the chemistry of Dalea spp. led to investigation of Dalea searlsiae, a plant native to areas of the western United States. Methanol extractions of D. searlsiae roots and subsequent chromatographic fractionation afforded the new prenylated and geranylated flavanones malheurans A–D (1–4) and known flavanones (5 and 6). Known rotenoids (7 and 8) and isoflavones (9 and 10) were isolated from aerial portions. Structure determination of pure compounds was accomplished primarily by extensive 1D- and 2D-NMR spectroscopy. The absolute configurations of compounds 1–5, 7 …

Lipid Dependence In Ras-Driven Tumors, Darin Salloum

Dissertations, Theses, and Capstone Projects

Over past decade, metabolic alterations in cancer cells have received a substantial amount of interest. It had been established that cancer cells undergo a significant amount of metabolic alterations, and some of these alterations are similar to those in normal highly proliferative cells. However, it is becoming more apparent that many of the metabolic alterations are specific to particular oncogenic signaling pathways. Although altered metabolic machinery makes cancer cells more efficient at promoting growth when nutrients are supplied at the sufficient amounts, the dependency of cancer cells on particular metabolic reprogramming deems cancer cells susceptible to disruptions within metabolic network. …

Metabolic Checkpoints In Cancer Cell Cycle, Mahesh Saqcena

Dissertations, Theses, and Capstone Projects

Growth factors (GFs) as well as nutrient sufficiency regulate cell division in metazoans. The vast majority of mutations that contribute to cancer are in genes that regulate progression through the G1 phase of the cell cycle. A key regulatory site in G1 is the growth factor-dependent Restriction Point (R), where cells get permissive signals to divide. In the absence of GF instructions, cells enter the quiescent G0 state. Despite fundamental differences between GF signaling and nutrient sensing, they both have been confusingly referred to as R and therefore by definition considered to be a singular event in G1. Autonomy from …

Determining The Standard Metabolic Rate Of The Mantis Shrimp, Squilla Empusa: The First Step In Calculating The Heat Increment Of Feeding, Emeline Marie Kelley

Biology Theses

The heat increment of feeding (HI_F) is the metabolic response following a feeding period. There is an increase in metabolism following a meal. The heat increment of feeding of the mantis shrimp, Squilla empusa, has not been studied before, although almost half of the published invertebrate HI_F studies have been on crustaceans.

The standard metabolic rate is the minimum metabolic rate of a postabsorptive ectotherm, at rest, during its non-active period, at a defined temperature. The standard metabolic rate (SMR) of the mantis shrimp was measured using indirect calorimetry, measuring the dissolved oxygen concentrations of the …

The Lipogenic Phenotype Of Her2/Neu-Positive Breast Cancer Cells, Jan Martin Baumann

Legacy Theses & Dissertations (2009 - 2024)

Recent work has shown that HER2/neu-positive breast cancer cells rely on a unique Warburg-like metabolism for survival and aggressive behavior. These cells are dependent on fatty acid (FA) synthesis, show markedly increased levels of stored fats and disruption of the synthetic process results in apoptosis. Supplementation of the growth media with physiological concentrations of saturated FAs induces cell death, whereas HER2-normal cells are not affected. This is particularly interesting in the context of new epidemiological data showing that a diet rich in saturated FAs is positively correlated with the development of HER2-negative disease, but not HER2/neu-positive disease.

Energy Tradeoffs Between Food Assimilation, Growth, Metabolism And Maintenance, Lihong Jiao

Masters Theses

"The effect of metabolic rate (MR) on organisms' health maintenance is a long-standing puzzle and empirical data on this issue is contradictory. A theoretical model was developed for understanding animal's energy budget under the food condition of Ad libitum (AL) and food restriction. This model offers a framework for understanding the role of MR and health maintenance mechanism from the perspective of energy tradeoff between food assimilation, growth, metabolism and maintenance. Hornworm (Manduca sexta larva) has been selected as an model to test the energetic tradeoff under different food supply and ambient temperatures. The changes in energy budget can …