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Full-Text Articles in Life Sciences

The Effect Of Testosterone On The Spring Migratory Phenotype Of A North American Songbird (Zonotrichia Albicollis), Caitlin L. Vandermeer Dec 2013

The Effect Of Testosterone On The Spring Migratory Phenotype Of A North American Songbird (Zonotrichia Albicollis), Caitlin L. Vandermeer

Electronic Thesis and Dissertation Repository

In passerines, the endocrine modulators responsible for seasonal changes in migratory behaviour and physiology are unclear. Spring photoperiods alter androgen levels, influencing muscle mass and fat deposition rates to power migration, as well as enhance nocturnal migratory restlessness activity (Zugunruhe). My study compared physiological indicators and migratory restlessness in castrated and intact white-throated sparrows (Zonotrichia albicollis) following photoperiod and hormone manipulation. Nocturnal restlessness activity was highest in migratory intact males or migratory castrated males that received testosterone replacement. Liver mass decreased in all photostimulated migratory groups regardless of testosterone treatment. Likewise, oxidative enzyme activity was unrelated to testosterone, but was ...


Connecting The Dots: Understanding Migration In The Context Of Other Periods Of The Annual Cycle, Kristina Lee Paxton Dec 2013

Connecting The Dots: Understanding Migration In The Context Of Other Periods Of The Annual Cycle, Kristina Lee Paxton

Dissertations

Migration is a fundamental characteristic of the life history of many organisms. Large-scale seasonal movements expose migratory species to an array of differing environmental conditions such that the ecology, behavior, and life history strategies of migratory species must balance selection pressures associated with each phase of the annual cycle. Therefore, scientists increasingly realize that to understand the ecology of a migratory species in any one phase of the annual cycle requires an understanding of how other phases may interact with and influence the period of interest. That said, following individuals throughout the year poses a serious challenge.

The focus of ...


Adhesion Molecule Regulation Of Regulatory T Cell Migration, Jessica Jean Loppnow Aug 2013

Adhesion Molecule Regulation Of Regulatory T Cell Migration, Jessica Jean Loppnow

Theses and Dissertations

Regulatory T (Treg) cells mediate tumor immune evasion by suppressing anti-tumor effector T cell responses in peripheral lymphoid tissues and within the tumor. While elevated Treg cell numbers have been shown to correlate with increased tumor growth, mechanisms that regulate their distribution within secondary lymphoid tissue and tumor tissue are not well understood. L-selectin, an adhesion molecule constitutively expressed on all classes of leukocytes, functions early in the adhesion cascade and regulates the migration of lymphocytes to lymph nodes through high endothelial venules. In addition, L-selectin can mediate migration of lymphocytes to sites of inflammation by binding to ligands present ...


The Effect Of Exogenous Leptin On Dendritic Cell Migration And Interactions With T Cells, Amanda L. Gonzales Jan 2013

The Effect Of Exogenous Leptin On Dendritic Cell Migration And Interactions With T Cells, Amanda L. Gonzales

Open Access Theses & Dissertations

Obesity is a complex, chronic disease that has reached epidemic proportions in the United States and shows no indication of receding. It is a state of chronic low-grade inflammation that is initiated by morphological changes in large accumulations of adipose tissue. Leptin is a pleiotropic hormone secreted by adipose tissue, presenting a possible link between obesity and inflammation. In this study, we assessed the effect of leptin on bone marrow-derived (BM) dendritic cells (DC) (BM-DC) function, antigen presenting cells vital for the activation of naí¯ve T cells. Previous data produced in our laboratory established that the addition of leptin ...