Temperature effects on moose (Alces alces) activity patterns in Isle Royale National Park

Moose (Alces alces) in Isle Royale National Park impact the ecosystem by browsing tree species and serving as the primary food source for wolves. As a heat-sensitive species, moose are susceptible to the impacts of climate change in the southern extent of their range which includes Isle Royale. Understanding how temperature impacts moose behavior is valuable and can be used to predict how moose may respond to changing temperature in the future. GPS enabled radio-collars with three-axis accelerometers were used to collect one year of temperature and activity data from 6 cow moose in Isle Royale National Park. The data was used to test the relationship between moose activity cycles and temperature using linear regression. Results show that moose activity patterns do change based on temperature. The relationship between temperature and moose behavior can be used to estimate moose browsing impact which determines food availability over time. Understanding the relationship between temperature and moose activity can be used to predict change in moose behavior in response to climate change, which would disrupt the successional progression of vegetation communities and alter the greater Isle Royale ecosystem in the future

Temperature effects on moose (Alces alces) activity patterns in Isle Royale National Park

Moose (Alces alces) in Isle Royale National Park impact the ecosystem by browsing tree species and serving as the primary food source for wolves. As a heat-sensitive species, moose are susceptible to the impacts of climate change in the southern extent of their range which includes Isle Royale. Understanding how temperature impacts moose behavior is valuable and can be used to predict how moose may respond to changing temperature in the future. GPS enabled radio-collars with three-axis accelerometers were used to collect one year of temperature and activity data from 6 cow moose in Isle Royale National Park. The data was used to test the relationship between moose activity cycles and temperature using linear regression. Results show that moose activity patterns do change based on temperature. The relationship between temperature and moose behavior can be used to estimate moose browsing impact which determines food availability over time. Understanding the relationship between temperature and moose activity can be used to predict change in moose behavior in response to climate change, which would disrupt the successional progression of vegetation communities and alter the greater Isle Royale ecosystem in the future

Determining species-specific false-positive rates using visual and auditory cues: a case study with sagebrush steppe songbirds

Errors in wildlife field data threaten to bias resulting abundance and occupancy estimates if not properly accounted for or minimized. Methods to account for false-positive errors in wildlife data have not been as thoroughly developed as those for false-negative errors despite false-positives being present across diverse wildlife taxa and study systems. The calibration method to account for false-positives involves assessing the field detection method to determine how often false-positive errors occur in the field data. Rates can then be incorporated into estimations based on the field data to improve estimation accuracy. This study presents an application of the calibration approach for multispecies avian abundance surveys of seven songbird species (Brewer’s Sparrow, Chestnut-collared Longspur, Horned Lark, Long-billed Curlew, Thick-billed Longspur, Vesper Sparrow, Western Meadowlark) in the sagebrush steppe and grassland ecosystem of eastern Montana. Completion of simulated avian surveys resulted in estimation of species-specific false-positive rates as well as examination of how rates may change with the availability of different identification cues. Visual identification cues (video of birds) were always available but auditory identification cues (bird vocalizations) were not always present. Approximately 15% of focal species identifications were false-positives (SD= 0.36). False-positive rates varied significantly between 15 out of 21 focal species pairs, ranging from rates of 0.003 to 0.402 (SD=0.054, SD=0.49). The availability of bird vocalizations in tandem with bird visuals did not differ significantly from false-positive rates based on visuals only (p=2e-16). These results suggest that among these species and study system false-positive rates are primarily a product of similarities in species morphology rather than vocalizations

Lower Affinity T Cells are Critical Components and Active Participants of the Immune Response

Kinetic and biophysical parameters of T cell receptor (TCR) and peptide:MHC (pMHC) interaction define intrinsic factors required for T cell activation and differentiation. Although receptor ligand kinetics are somewhat cumbersome to assess experimentally, TCR:pMHC affinity has been shown to predict peripheral T cell functionality and potential for forming memory. Multimeric forms of pMHC monomers have often been used to provide an indirect readout of higher affinity T cells due to their availability and ease of use while allowing simultaneous definition of other functional and phenotypic characteristics. However, multimeric pMHC reagents have introduced a bias that underestimates the lower affinity components contained in the highly diverse TCR repertoires of all polyclonal T cell responses. Advances in the identification of lower affinity cells have led to the examination of these cells and their contribution to the immune response. In this review we discuss the identification of high- versus low-affinity T cells as well as their attributed signaling and functional differences. Lastly mechanisms are discussed that maintain a diverse range of low- and high-affinity T cells

CD43 modulates severity and onset of experimental autoimmune encephalomyelitis.

Experimental autoimmune encephalomyelitis (EAE) is a mouse model of multiple sclerosis characterized by infiltration of activated CD4(+) T lymphocytes into tissues of the CNS. This study investigated the role of CD43 in the induction and progression of EAE. Results demonstrate that CD43-deficient mice have reduced and delayed clinical and histological disease severity relative to CD43(+/+) mice. This reduction was characterized by decreased CD4(+) T cell infiltration of the CNS of CD43(-/-) mice but similar numbers of Ag-specific T cells in the periphery, suggesting a defect in T cell trafficking to the CNS. The absence of CD43 also affected cytokine production, as myelin oligodendrocyte glycoprotein (MOG) 35-55-specific CD43(-/-) CD4(+) T cells exhibited reduced IFN-gamma and increased IL-4 production. CD43(-/-) CD4(+) MOG-primed T cells exhibited reduced encephalitogenicity relative to CD43(+/+) cells upon adoptive transfer into naive recipients. These results suggest a role for CD43 in the differentiation and migration of MOG(35-55)-specific T cells in EAE, and identify it as a potential target for therapeutic intervention

Insights into T Cell Recognition of Antigen: Significance of Two-Dimensional Kinetic Parameters

The T cell receptor (TCR) interacts with peptide-major histocompatibility complex (pMHC) to enable T cell development and trigger adaptive immune responses. For this reason, TCR:pMHC interactions have been intensely studied for over two decades. However, the details of how various binding parameters impact T cell activation remain elusive. Most measurements were made using recombinant proteins by surface plasmon resonance, a three-dimensional (3D) technique in which fluid-phase receptors and ligands are removed from their cellular environment. This approach found TCR:pMHC interactions with relatively low affinities and slow off-rates for agonist peptides. Newer generation techniques have analyzed TCR:pMHC interactions in two dimensions (2D), with both proteins anchored in apposing plasma membranes. These approaches reveal in situ TCR:pMHC interaction kinetics that are of high affinity and exhibit rapid on- and off-rates upon interaction with agonist ligands. Importantly, 2D binding parameters correlate better with T cell functional responses to a spectrum of ligands than 3D measures

Low 2-Dimensional CD4 T Cell Receptor Affinity for Myelin Sets in Motion Delayed Response Kinetics

T cells recognizing self-peptides that mediate autoimmune disease and those that are responsible for efficacious immunity against pathogens may differ in affinity for antigen due to central and peripheral tolerance mechanisms. Here we utilize prototypical self-reactive (myelin) and viral-specific (LCMV) T cells from T cell receptor (TCR) transgenic mice (2D2 and SMARTA, respectively) to explore affinity differences. The T cells responsive to virus possessed >10,000 fold higher 2D affinity as compared to the self-reactive T cells. Despite their dramatically lower affinity for their cognate ligand, 2D2 T cells respond with complete, albeit delayed, activation (proliferation and cytokine production). SMARTA activation occurs rapidly, achieving peak phosphorylation of p38 (1 minute), Erk (30 minutes), and Jun (3 hours) as well as CD69 and CD25 upregulation (3 and 6 hours, respectively), with a corresponding early initiation of proliferation. 2D2 stimulation with MOG results in altered signaling – no phospho-Erk or phospho-p38 accumulation, significantly delayed activation kinetics of Jun (12 hours), and delayed but sustained SHP-1 activity – as well as delayed CD69 and CD25 expression (12–24 hours), and slow initiation of proliferation. This delay was not intrinsic to the 2D2 T cells, as a more potent antigen with >100-fold increased 2D affinity restored rapid response kinetics in line with those identified for the viral antigen. Taken together, these data demonstrate that time can offset low TCR affinity to attain full activation and suggest a mechanism by which low affinity T cells participate in autoimmune disease