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Research Interests

My research interests are very broad including the molecular and environmental basis of aging, stress responses in social insects, and biology education. The current focus of my work is the insect homologue of Extra-Cellular Superoxide Dismutase that I discovered in the ant Lasius niger. I am supervising undergraduate students exploring various aspects of aging in Drosohpila including the interactions of genetic background, Wolbachia infection, social environment, and oxidative stress on lifepsan.


Extra-Cellular Superoxide Dismutase

I am currently characterizing the extra-cellular SOD in Drosophila melanogaster. The Superoxide Dismutase family of antioxidants has long been thought involved in aging by protecting various cellular compartments from oxidative damage. Recently, the evidence is suggesting that it not a general protective role (proposed by the free radical theory of aging), but more likely an involvement in reactive oxygen signalling that mediates the effects on aging. The next steps after understanding how the superoxide dismutases work together, or separately, will be to investigate how they might affect lifespan through cellular signalling.

How Genetic Background and Environment Affects Aging

My undergraduate research students and my Biology of Aging Class (Bio 339) studying how genetic background affects aging under different conditions. We use two wild caught lines that have different lifespans (one from the Plattsburgh side of Lake Champlain, and one from the Burlington side). So far we have noted different effects on lifespan with infection by Wolbachia, by oxidative stress, and responses to various treatments that have been shown to affect aging including social environment. Three of these projects were presented with posters at the Allied Genetics Conference in Orlando Florida (July 2016). Florian Capobianco (poster) , Presila Bejo (poster) and I presented work by three students (Terrel Segre, Jason Tromblee and Joanna Binns) who could not attend (poster). Work on these questions in my lab is continuing with Sean Michael Nandkumar (Wolbachia and oxidative stress), Terrel Segre (social effects on lifespan) and Dara Cunnignham who has a new angle looking at inherited epigenetic effects.


Kin-Selected Conflict and the Evolution of Lifespan and aging

The conventional view of the evolution of aging is incomplete, because it omits social effects. Normally an individual's death benefits only the unrelated conspecifics who gain access to the resources it leaves behind. But in a population made up of groups of relatives, death of one individual can benefit its related group-mates. This affects the evolution of lifespan and aging through kin selection. An example is the case of a parent whose death releases a resource such as a nest or territory, required by an offspring to breed (resource inheritance). Eventually this benefits the offspring, creating an incentive for the parent to die prematurely, but there is a twist; parent and offspring do not always 'agree' on the exact timing of parental death and resource handover. There can be offspring/parent conflicts in social insect systems such as in Bumble bees where a queen can gain more fitness by dying and allowing the offspring to reproduce than by remaining alive.
Along with Andrew Bourke at the University of East Anglia we tested the hypothesis that kin-selected conflict over resource inheritance affects lifespan and aging using the bumble bee Bombus terrestris as our experimental system. The Bourke lab first carried out behavioural experiments studying conflicts in the timing of inheritance from queen to worker. We predict that evolution will favour rapid aging in the queens only when transfer of the nest is favoured from her perspective. In Southampton, Gabrielle Lockett did a post doctoral project testing genes known to be indicators of aging in other social insects act likewise in these queens. NERC_logo.jpgThe project is now over and one paper is out (Lockett et al., 2016) and another manuscript is in prep describing results relevant to understanding how famial and social relationships affect the evolution of aging.


Trade-Offs Immunity, aging, and Neurodegeneration

Kirstin Williamson recently earned her Ph.D on a project with Dr.’s Amrit Mudher, Lex Kraaijeveld, and I. We used a fly model to investigate the link between stress, immunity levels and neurodegeneration. Fruit flies (Drosophila melanogaster) in nature vary in their immunity against parasites and pathogens and this immunity has been shown to carry costs. We used this naturally-occurring variation in Drosophila immunity by establishing genetic lines with high and low levels of immunity to parasitism. The results are now being written up and hopefully will be published soon. Jointly funded by:

lableled fly neuron

Social Insect Molecular Stress Responses From Climate Change

We just wrapped up a REU NSF funded study on the interaction of the heatshock response and environmental stressors anticipated from global climate change. This supplemental project using a local ant as the model organism was done with Sara Cahan and Nick Gotelli at UVM. The PSU student recruited (Skyler Resendez) spent two months at UVM in the Cahan lab developing and running experiments with graduate student Andrew Nguyen and UVM undergraduate Kerri Pinder. The results were presented at the ESA meeting in November in Austin Texas (poster abstract).
NSF logo
In the meanwhile, two undergradutes at PSU, Brian Whyte and Samantha Tremblay also worked on the contribution of social behavior on how ants respond to thermal stress.


How does the LRRK2 gene cause familial Parkinson's disease?

This project was born out of efforts to broaden our 4th year cell biology course lab (Bio 401) to include C. elegans as a model system. The students have developed a novel protocol to assess the effects of various chemicals on worms carrying a copy of the normal and mutant human LRRK2 gene that is associated with an inherited form of Parkinson's disease. The project is now being pursued both in the class and as part of an independent undergraudate research project.


Teaching Research and Development

I am also very interested in education theory and practice. Evolution is one particularly challenging topic that has caught my attention. Rich Edwards, David Milliard, Nicola Asamoah, Matt Taylor, and other collaborators at Southampton are developed a web application (Maptime) to make Google map timelines of deep time as described in Parker 2011. I also worked with Rich Edwards setting up a popular website showing how to construct UPGMA trees from distance matrices.

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