Biology subjects

Valencia, A. P.

Publications and source records attributed to Valencia, A. P..

3 recordsLinked to original sources

bioRxiv2021

Breakout Rooms, Polling, and Chat, Oh My! The Development and Validation of Online COPUS

We developed and validated a new classroom observation protocol, Online COPUS (E-COPUS), to measure teaching and learning practices in the online learning environment. We collected COPUS and E-COPUS data from 40 STEM courses before, during the transition, and continuation of emergency remote teaching (ERT). Through weekly discussions among observers, we adjusted six of the original instructor COPUS code descriptions and six of the original student code descriptions to fit the online learning environment. We trained 23 observers to conduct E-COPUS utilizing both in-person and online lecture recordings. To validate E- COPUS, we consulted an expert panel of science educators and education researchers to provide feedback on our code descriptions and complete a matching activity with our E-COPUS code descriptions. We further examined E-COPUS by analyzing the teaching and learning practices of 6 instructors across in-person and online instruction and found that the online functions of breakout rooms, polling, and the chat were utilized to promote active learning activities in the online learning environment. As we prepare for teaching in the future, it is important to have formative assessment tools designed for all course formats to support assessment and improvement of teaching practices in college STEM classrooms.

scientific communication and education↗

bioRxiv2021

High intensity muscle stimulation activates a systemic Nrf2-mediated redox stress response

IntroductionHigh intensity exercise is an increasingly popular mode of exercise to elicit similar or greater adaptive responses compared to traditional moderate intensity continuous exercise. However, the molecular mechanisms underlying these adaptive responses are still unclear. The purpose of this pilot study was to compare high and low intensity contractile stimulus on the Nrf2-mediated redox stress response in mouse skeletal muscle. MethodsAn intra-animal design was used to control for variations in individual responses to muscle stimulation by using a stimulated limb (STIM) and comparing to the contralateral unstimulated control limb (CON). High Intensity (HI - 100Hz), Low Intensity (LI - 50Hz), and Naive Control (NC - Mock stimulation vs CON) groups were used to compare these effects on Nrf2-ARE binding, Keap1 protein content, and downstream gene and protein expression of Nrf2 target genes. ResultsMuscle stimulation significantly increased Nrf2-ARE binding in LI-STIM compared to LI-CON (p = 0.0098), while Nrf2-ARE binding was elevated in both HI-CON and HI-STIM compared to NC (p = 0.0007). The Nrf2-ARE results were mirrored in the downregulation of Keap1, where Keap1 expression in HI-CON and HI-STIM were both significantly lower than NC (p = 0.008) and decreased in LI-STIM compared to LI-CON (p = 0.015). In addition, stimulation increased NQO1 protein compared to contralateral control regardless of stimulation intensity (p = 0.019). ConclusionsTaken together, these data suggest a systemic redox signaling exerkine is activating Nrf2-ARE binding and is intensity gated, where Nrf2-ARE activation in contralateral control limbs were only seen in the HI group. Other research in exercise induced Nrf2 signaling support the general finding that Nrf2 is activated in peripheral tissues in response to exercise, however the specific exerkine responsible for the systemic signaling effects is not known. Future work should aim to delineate these redox sensitive systemic signaling mechanisms.

molecular biology↗

bioRxiv2021

Metabolic function in aging retina and retinal pigment epithelium remains robust despite vision loss

PurposeCharacterize how metabolic function in the murine retina and retinal pigment epithelium-choroid-sclera (eyecup) complex is impacted by natural aging. MethodsWe examined scotopic and photopic visual function of young (3-6 months) and aged (23-26 months) C57Bl/6J mice using electroretinograms (ERGs). Metabolic changes in retina and eyecup explants were characterized by measuring uptake and usage of U-13C-glucose or U-13C-glutamine at different timepoints by gas chromatography-mass spectrometry (GC-MS), measuring oxygen consumption rate (OCR) using a perifusion apparatus, and determining ATP levels with a bioluminescence assay. ResultsScotopic and photopic ERG responses declined in aged mice. Glucose metabolism, glutamine metabolism, OCR, and ATP pools in retinal explants were mostly unaffected by the age of the mouse. In eyecups, glutamine usage in the Krebs Cycle decreased while glucose metabolism, OCR, and ATP pools remained stable. ConclusionsThe ex vivo approach in our study to examine aging glucose and glutamine metabolism in retina and RPE showed negligible impact of age on retina and an impairment of glutamine anaplerosis in eyecups. The surprising metabolic stability of these tissues ex vivo suggests age-related metabolic alterations in these tissues may not be intrinsic. Future experiments should focus on determining whether external factors including nutrient supply, oxygen availability, or other structural changes influence ocular metabolism in vivo.

biochemistry↗