C-terminal fusion of eGFP to the bradykinin B-2 receptor strongly affects down-regulation but not receptor internalization or signaling

A functional comparison was made between the wildtype bradykinin B, receptor (B(2)wt) and the chimera B(2)eGFP (enhanced green-fluorescent protein fused to the C-terminus of B(2)Wt), both stably expressed in HEK 293 cells. There was almost no difference in terms of ligand-inducible receptor phosphorylation and internalization, signal transduction (accumulation of inositol phosphates) or expression and affinity. However, stimulation for up to 8 h with 10 mu M bradykinin (BK) resulted in a strong decrease in surface receptors (by 60% within 5 h) in B(2)Wt, but not in B(2)eGFP. When the expression levels of both constructs where comparably reduced using a weaker promoter, long-term stimulation resulted in a reduction in surface receptors for B(2)wt(low) to less than 20% within 1 h, whereas the chimera B(2)eGFP(low) still displayed 50% binding activity after 2 h. A 1-h incubation in the absence of BK resulted in a recovery of 60% of the binding in B(2)wt(low) after 1-h stimulation with BK, but of only 20% after 7-h stimulation. In contrast, B(2)eGFP(low) levels were restored to more than 70%, even after 7-h stimulation. These data indicate that although the fusion of eGFP to B(2)wt does not affect its ligand-induced internalization, it strongly reduces the down-regulation, most likely by promoting receptor recycling over degradation

Applying a social-ecological systems approach to human-bear encounters across the Pacific Rim: advancing resilient human-wildlife management strategies

Thesis (M.S.) University of Alaska Fairbanks, 2014.Wildlife management is challenged with addressing human resource needs while simultaneously conserving wildlife populations. Conflicts between humans and wildlife have increased across Northern countries with the expansion of human communities and environmental changes. Lack of information exists about reasons for such occurrences. This study explores adaptive capacity and resilience in coupled human-wildlife systems through the analysis of social and ecological factors contributing to perceptions of negative and positive human-bear (Ursus spp.) encounters. I first developed a theory to evaluate human perceptions and behaviors during human-wildlife encounters. Secondly I adopted an interdisciplinary framework to analyze human-bear encounters in urbanizing regions of south Sakhalin Island, Russian Far-East, and southcentral Alaska, USA. These case studies facilitate an analysis of perception development across spatial and social scales while incorporating approaches of both social and ecological sciences. Hunting, tourism and overall anthropogenic impacts are central to bear management, whereas cultural and social interests are perceived to not be considered in bear management decision-making across study regions. In Alaska, political interests are prevalent in bear management, whereas on Sakhalin, economic interests, including illegal animal trade and poaching prevail. Across study regions the perception of an encounter with a bear was dependent on the socio-economic situation of the individual having the encounter. The higher a person's socio-economic status was, the higher was their probability to perceive bear encounters as positive. Further, spatial and social scales across which perceptions vary are identified. Scales include urban-non-urban areas, wildland-urban interfaces, and a recreation-subsistence interest divide. Outside of urban areas, people's interests in recreation versus subsistence affect their perceptions toward bear encounters. Subsistence collectors of fish, game or plants are more likely to have negative encounters. Within urban areas, increased experience with encountering bears and length of residency are associated with positive encounters, whereas closeness to residences while not in sheltered environments increases negative encounters. These findings constitute spatial and social barriers and benefits to individualistic perception formation during human-bear encounters. Their identification advances resilience in researched human-wildlife systems and helps us to understand the adaptive capacities within these communities. The successful spatially-explicit integration of social and ecological variables promotes the opportunities for integrating human dimensions in wildlife management.General Acknowledgements -- Chapter 2: Integrating complexity in the management of human-wildlife encounters -- Chapter 3: Understanding local peoples' perceptions toward bear management in Northern urbanizing regions -- Chapter 4: Spatial explicit perception mapping: socio-economic circumstances to impact perceptions and spatial pattern of human-bear encounters across scale -- Chapter 5: The impact of spatially explicit ecological and social variables on the development of perceptions during bear encounters in southcentral Alaska -- Chapter 6: General conclusions and future recommendations -- Appendices