Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 5 of 5

Full-Text Articles in Entire DC Network

Interaction Of Stretch Feedback And Beat Regularity In Response To Amgseflamide In The Heart Of Homarus Americanus, William Allen Jan 2020

Interaction Of Stretch Feedback And Beat Regularity In Response To Amgseflamide In The Heart Of Homarus Americanus, William Allen

Honors Projects

Central pattern generators (CPGs) are neural circuits whose component neurons possess intrinsic properties and synaptic connections that allow them to generate rhythmic motor outputs in the absence of descending inputs. The cardiac ganglion (CG) is a nine-cell CPG located in the American lobster, Homarus americanus. Stretch of the myocardium feeds back to the CG through mechano-sensitive dendrites and is thought to play a role in maintaining regularity in the beating pattern of the heart. The novel peptide AMGSEFLamide has been observed to induce irregular beating patterns when applied at high concentrations. This study investigated the interaction between stretch-related feedback …


The Role Of Behavioral Diversity In Determining The Extent To Which The Cardiac Ganglion Is Modulated In Three Species Of Crab, Grace Bukowski-Thall Jan 2020

The Role Of Behavioral Diversity In Determining The Extent To Which The Cardiac Ganglion Is Modulated In Three Species Of Crab, Grace Bukowski-Thall

Honors Projects

Central pattern generators (CPGs) are neural networks that generate the rhythmic outputs that control behaviors such as locomotion, respiration, and chewing. The stomatogastric nervous system (STNS), which contains the CPGs that control foregut movement, and the cardiac ganglion (CG), which is a CPG that controls heartbeat, are two commonly studied systems in decapod crustaceans. Neuromodulators are locally or hormonally released neuropeptides and amines that change the output patterns of CPGs like the STNS and CG to allow behavioral flexibility. We have hypothesized that neuromodulation provides a substrate for the evolution of behavioral flexibility, and as a result, systems exhibiting more …


Living Upstream: Kennebec River Influence On Nutrient Regimes And Phytoplankton Communities In Harpswell Sound, Siena Brook Ballance Jan 2020

Living Upstream: Kennebec River Influence On Nutrient Regimes And Phytoplankton Communities In Harpswell Sound, Siena Brook Ballance

Honors Projects

Phytoplankton underpin marine trophic systems and biogeochemical cycles. Estuarine and coastal phytoplankton account for 40-50% of global ocean primary productivity and carbon flux making it critical to identify sources of variability. This project focuses on the Kennebec River and Harpswell Sound, a downstream, but hydrologically connected coastal estuary, as a case study of temperate river influence on estuarine nutrient regimes and phytoplankton communities. Phytoplankton pigments and nutrients were analyzed from water samples collected monthly at 8 main-stem rivers stations (2011-2013) and weekly in Harpswell Sound (2008-2017) during ice-free months. Spatial bedrock and land use impacts on river nutrients were investigated …


Responses Of Central Pattern Generators In The American Lobster Stns To Multiple Members Of A Novel Neuropeptide Family, Benjamin Harley Wong Jan 2020

Responses Of Central Pattern Generators In The American Lobster Stns To Multiple Members Of A Novel Neuropeptide Family, Benjamin Harley Wong

Honors Projects

Neuropeptides are important modulators of neural activity, allowing neural networks, such as the central pattern generators (CPGs) that control rhythmic movements, to alter their output and thus generate behavioral flexibility. Isoforms of a neuropeptide family vary in physical structure, allowing potentially distinct functional neuromodulatory effects on CPG systems. While some familial neuropeptide isoforms can differentially affect a system, others in the same family may elicit indistinguishable effects. Here, we examined the effects elicited by members of a novel family of six peptide hormone isoforms (GSEFLamides: I-, M-, AL-, AM-, AV-, and VM-GSEFLamide) on the pyloric filter and gastric mill CPGs …


Mechanisms Underlying Variable Responses To The Neuropeptide C-Type Allatostatin (Ast-C) Across Isoforms And Among Individuals In The American Lobster, Homarus Americanus, Audrey J. Muscato Jan 2020

Mechanisms Underlying Variable Responses To The Neuropeptide C-Type Allatostatin (Ast-C) Across Isoforms And Among Individuals In The American Lobster, Homarus Americanus, Audrey J. Muscato

Honors Projects

Central pattern generators (CPGs) produce patterned outputs independent of sensory input. The cardiac neuromuscular system of the American lobster (Homarus americanus) is driven by a CPG called the cardiac ganglion (CG), which is composed of nine neurons, making it a model system of study. Modulation of CPGs allows for functional flexibility. One neuropeptide family that modulates the CG is C-type allatostatin (AST-C I-III). Previous research has shown variation in the responses of the CG across the three isoforms and among individuals. First, we investigated why AST-C I and III elicit responses that are more similar to each other than they …