2021 Physical Sciences

The pre-recorded talks and posters on this page showcase the work of students who received NC Space Grant research funding for the 2019-20 and 2020-21 academic years. The menu at right provides links to pre-recorded talks and posters by other funded students on additional topics.

Jaden Miller 

2020-2021 NC Space Grant Undergraduate Research Scholar
Appalachian State University
Undergraduate Student (Junior), Applied Physics

Laser-Based Position Detection in Optical Tweezers

The Biophysics and Optical Sciences Facility (BiyOSeF) houses a custom-built optical tweezer (OT) system. An OT system uses focused laser light to confine and manipulate nano- to micrometer-scale particles. When trapping such particles, position detection techniques are employed to verify the effectiveness of a trap. First, the optimal sample slide position in the microscope is established. Once the slide is positioned, the exact location of the particle in the trap is determined using laser-based position detection systems. Laser incidence on a particle in a trap results in a diffraction pattern, which encounters a position sensing detector (PSD) that provides position data in units of volts. The voltage data is converted into nanometers and analyzed for the true particle position data. We present here an overview of the methods and instrumentation of the OT system.

Faculty Advisor: Brooke Hester

Amanda Smythers 

2020-2021 NC Space Grant Graduate Research Fellow
The University of North Carolina at Chapel Hill
Graduate Student (Ph.D.), Chemistry

Translational regulation of tardigrade extremotolerance unveiled by proteomics 

Tardigrades are eight-legged microscopic invertebrates capable of surviving desiccation, radiation, and other extreme stressors. The crucial adaptation enabling tardigrade survival is their ability to temporarily suspend metabolism via cryptobiosis, an ametabolic state often accompanied by a ‘tun’ form through which tardigrades undergo morphological changes. These changes include the retraction of their limbs, water loss of up to 98%, the synthesis of cryotolerant disaccharides, and protein rearrangement. However, despite these distinct physiological changes, genetic approaches have unveiled minor differences in tardigrades upon initiation of cryobiotic states as well as an absence of highly conserved gene networks known to mediate environmental stress stimuli in higher order organisms. This indicates that either translational and/or post-translational regulation is responsible for the mechanisms enabling survival to extreme external stressors, and that proteins hold the key to tardigrade extremotolerance. In this study, we explored the translational response of tardigrades to cryptobiosis by integrating global proteomic analysis with biochemical characterization. By optimizing a detergent-free extraction method, we were able to quantify 2,400 tardigrade proteins, a 59% increase from previously published work. This enabled thorough investigation of proteomic regulation following cryptobiosis induction, and unveiled a coordinated network of protein regulation that upregulated proteins related to oxidative stress and mitochondrial respiration while downregulated proteins related to calcium flux and apoptosis. This work supports a role for redox metabolism in tardigrade tun induction, and was further validated through the quantification of reactive oxygen species via electron paramagnetic spectroscopy and confocal fluorescent microscopy. Together, these data provide a framework for future investigations of redox response in tardigrades.

Faculty Advisor: Leslie M. Hicks