Biological Sciences
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Item Traumatic Brain Injury: Assessing The Pathogenic Impact Of Chronic Smoking And Potential Countermeasures(2022-11-04) Sivandzade, Farzane; Cucullo, Luca; Al-Shabrawey, Mohamed; Liu ZijuanTraumatic brain injury is among the most prevalent causes of cerebrovascular and neurological damage worldwide. Premorbid conditions such as smoking could exacerbate post-traumatic brain injury damage and impact recovery due to vascular endothelial dysfunction. Cigarette smoke produces reactive oxygen species (ROS) and oxidative stress (OS), driving endothelial dysfunction and damaging the blood-brain barrier (BBB) endothelium. Interestingly, these pathogenic modulators of BBB impairment are similar to those initiated by hyperglycemia. Thus, this work investigated the pathophysiological mechanisms underlying traumatic brain injury (TBI) exacerbation following chronic smoking and vaping exposure to determine key pathological parameters leading to loss of BBB function and integrity. I also assessed the effectiveness of metformin and rosiglitazone to prevent/reduce the loss of BBB function and integrity and protect the brain from the exacerbation of post-TBI likely promoted by the chronic exposure to tobacco smoke (TS) or electronic cigarette (EC) vape and unravel the corresponding mechanism (s) of action. For this purpose, I used both in vitro (primary brain microvascular endothelial cells) and in vivo mice models (male and C57BL/6J mice) subjected to TS/EC and TBI, with/without antidiabetic treatments. The outcomes of these studies would define the complex interplay between smoking and TBI and lead to new approaches for alleviating TBI outcomes.Item The New Zealand Mud Snail (Potamopyrgus Antipodarum) Ecology And Management Of A Global Invader(2022-07-28) Gist, Jeremy A.; Tiegs, Scott; Berven, Keith; Luttenton, Mark; Strayer, DavidThe New Zealand mud snail (Potamopyrgus antipodarum; NZMS) is among the most globally widespread aquatic invaders, colonizing at least 40 countries across 6 continents. NZMS have recently colonized rivers of the Laurentian Great Lakes region. where little is known about their impacts on the native communities of the ecosystems they invade. In chapter one, I present the results of a systematic review of 245 articles, and outline NZMS impacts, distribution, population dynamics, vectors of spread, and management. The invasion success of NZMS stems from their opportunistic traits allowing them to tolerate broad ranges of environmental conditions. However, optimal conditions for successful establishment are evident. NZMS can become exceptionally abundant and impact multiple facets of aquatic ecosystems, though populations can fluctuate seasonally and over longer time scales, likely due to environmental constraints. In chapter two, I tested the efficacy of three different chemical reagents for NZMS decontamination on recreational fishing gear and combined these results with results of a self-administered public survey gauging the level of willingness individuals have to participate in a given NZMS decontamination technique. The greatest mortality of NZMS was caused by Formula 409, and participants of the survey revealed Formula 409 to be the chemical they'd be most willing to use. Chapter three outlines an investigation of the effects of NZMS on the diets and condition of fish in a recently invaded stream, the Au Sable River (Michigan, USA). Trout consumed NZMS throughout the duration of the study, while sculpin minimally consumed NZMS. Of the 83 trout collected, 60% contained NZMS in their stomachs. Age 2 trout that consumed NZMS exhibited reduced condition relative to those that contained fewer NZMS. Lastly, chapter four consists of a study to characterize NZMS population dynamics and their effects on native benthic invertebrates in the Au Sable River. NZMS populations exhibited pronounced seasonality with peak densities typically occurring during the Summer and Autumn of each year. NZMS numerically dominated the benthic community and were associated with differences in the overall benthic community composition. The results of these studies highlight how NZMS can affect native communities and higher consumers in rivers of the Great Lakes region and contribute to a more robust understanding of the global NZMS invasion, such that undesired impacts can be minimized or averted.