Showing 1 - 10 of 21 Items

- Embargo End Date: 2027-05-16
Date: 2024-01-01
Creator: Everett Horch
Access: Embargoed
Date: 2015-03-01
Creator: Aidan W. Short, David B. Carlon
Access: Open access
- A new wave of green crabs Carcinus maenus is sweeping through the Gulf of Maine (GOM). While first reports of green crabs in the GOM date from the early 1900s, populations in southern GOM have exploded in the last five years. In the Casco Bay region, this unusually high abundance is associated with poor commercial shellfish landings and the decline of eel grass habitat (Zostera marina). To determine the mechanistic roles green crabs play in direct and indirect ecological interactions, it is important to understand diet breadth, and how feeding preferences change in response to ecological context. Since green crabs are omnivorous, traditional approaches to diet analysis via hard parts suffer from substantial bias. We are using DNA barcoding and next generation sequencing (NGS) to analyze green crab diets from a longitudinal sampling design in Casco Bay. In addition to a temporal dimension, our design includes two habitats: clam flats and eel grass beds. We have now sampled ~ 1000 crabs and have processed 460 individual stomachs from a range of sizes and both sexes. Here we will present: our sampling design, our NGS pipeline, and preliminary analysis from a lobster-specific (Homarus americanus) probe. Presenting author status: Undergraduate Preferred presentation type: Poster Preferred topics: 3. Biological invasions; 18. Molecular ecology Benthic Ecology Meeting, 2015 Quebec City, Canada Aidan Short was an undergraduate student at Bowdoin College when this research was conducted.
Date: 2024-01-01
Creator: Grant Griesman
Access: Open access
- Central pattern generators (CPGs) are neuronal networks that produce rhythmic motor output in the absence of sensory stimuli. Invertebrate CPGs are valuable models of neural circuit dynamics and neuromodulation because they continue to generate fictive activity in vitro. For example, the cardiac ganglion (CG) of the Jonah crab (Cancer borealis) and American lobster (Homarus americanus) contains nine electrochemically coupled neurons that fire bursts of action potentials to trigger a heartbeat. The CG is modulated by neuropeptides, amines, small molecule transmitters, gases, and mechanosensory feedback pathways that enable flexibility and constrain output. One such modulator, the SLY neuropeptide family, was previously shown to be expressed in hormonal release sites and within the CG itself and has unusual processing features. However, its physiological effect was unknown. Here, I performed dose-response experiments in the crab and lobster whole heart and isolated CG to determine the threshold concentration of SLY neuropeptides to which these systems respond. The crab isoform had strong, excitatory effects in the crab whole heart and weakly modulated the crab CG. The lobster isoform weakly modulated the lobster whole heart and CG. Surprisingly, the crab isoform exerted large, variable effects on the lobster system, which suggests that SLY neuropeptides, their receptors, and their signaling pathways may be evolutionarily conserved across these two species. This research contributes to our understanding of how neural circuits can generate flexible output in response to modulation. It may also offer insight into processes influenced by peptidergic neurotransmission in the nervous systems of other animals, including mammals.

Date: 2013-05-01
Creator: Patrick J Lariviere
Access: Access restricted to the Bowdoin Community

- Restriction End Date: 2028-06-01
Date: 2023-01-01
Creator: Ean Lev Small
Access: Access restricted to the Bowdoin Community

Date: 2020-01-01
Creator: Frances DeCamp Hobart Zorensky
Access: Access restricted to the Bowdoin Community

- Embargo End Date: 2027-05-16
Date: 2024-01-01
Creator: Sarah Conant
Access: Embargoed

Date: 2019-05-01
Creator: Natasha Ann Belsky
Access: Access restricted to the Bowdoin Community

Date: 2014-05-01
Creator: Divya Hoon
Access: Access restricted to the Bowdoin Community

Date: 2021-01-01
Creator: Sheikh Omar Kunjo
Access: Access restricted to the Bowdoin Community