College of Sciences
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Browsing College of Sciences by Department "Integrative Biology"
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Item Correlated Oxidative Stress and Mitochondrial Abnormalities in Aging are Discontinuous with Alzheimer’s Disease(Office of the Vice President for Research, 2018) Nguyen, Richard Q.; Bach, Stephan H.; Phelix, Clyde F.; Perry, GeorgeOxidative stress and mitochondrial damage precede Alzheimer’s disease (AD) hallmark pathologies, neurofibrillarytangles (NFT), and senile plaques.Mitochondria’s exact role in oxidation of pyruvate and NADH play a critical role in oxidative damage. We conducted this study to identify the relationship of oxidized RNA, 8--OHG biomarker, and mtDNA accumulation in AD and aging individuals. Abnormalities were examined by using densitometry of hippocampal pyramidal neurons: mtDNA accumulation as a marker of mitophagy and oxidative damage by 8-OHG. Among aging individuals, 8-OHG and mtDNA accumulation were highly correlated (R2=0.87,p=0.0007). While both 8-OHG and mtDNA were at higher levels in AD individuals, they were uncorrelated (R2=0.4418,p=0.07).In AD individuals, 8-OHG was inversely correlated with amyloid-β, while in aging, there was no significant correlation. These results suggest the discontinuity of similarities between aging and AD. These findings also indicate that the onset of AD is marked by a pleotrophic change in oxidative stress, one characterized by a change from mitochondria degeneration to amyloid-β independency.Item Defense Priming and Jasmonates: A Role for Free Fatty Acids in Insect Elicitor-Induced Long Distance Signaling(2016-01-08) Li, Ting; Cofer, Tristan; Engelberth, Marie; Engelberth, JurgenGreen leaf volatiles (GLV) prime plants against insect herbivore attack resulting in stronger and faster signaling by jasmonic acid (JA). In maize this response is specifically linked to insect elicitor (IE)-induced signaling processes, which cause JA accumulation not only around the damage site, but also in distant tissues, presumably through the activation of electrical signals. Here, we present additional data further characterizing these distal signaling events in maize. Also, we describe how exposure to GLV increases free fatty acid (fFA) levels in maize seedlings, but also in other plants, and how increased fFA levels affect IE-induced JA accumulation. Increased fFA, in particular α-linolenic acid (LnA), caused a significant increase in JA accumulation after IE treatment, while JA induced by mechanical wounding (MW) alone was not affected. We also identified treatments that significantly decreased certain fFA level including simulated wind and rain. In such treated plants, IE-induced JA accumulation was significantly reduced when compared to un-moved control plants, while MW-induced JA accumulation was not significantly affected. Since only IE-induced JA accumulation was altered by changes in the fFA composition, we conclude that changing levels of fFA affect primarily IE-induced signaling processes rather than serving as a substrate for JA.Item Developmental Stages Affect the Capacity to Produce Aldehyde Green Leaf Volatiles in Zea mays and Vigna radiata(2022-02-15) Engelberth, Jurgen; Engelberth, MarieGreen leaf volatiles (GLV) are essentially produced by the green parts of plants upon damage. GLV are mainly 6-carbon molecules derived from fatty acids through the hydroperoxide lyase pathway and can serve as airborne signals to other parts of the same plant and to neighboring plants and help to protect them against biotic and abiotic stresses. However, while the biosynthesis is generally well understood, little is known about how plants regulate the production of these important signaling molecules. To better understand how the developmental stage of the plant affects aldehyde GLV production, we selected Zea mays and Vigna radiata to represent mono- and dicot plants for this analysis. We show that the capacity to produce aldehyde GLV strongly depends on the developmental stage of the plant. Major differences in the quantity, and in the quality of these compounds were found, not only in leaves from different developmental stages, but also in different areas within a leaf. The results demonstrate that the capacity to produce GLV varies significantly within a plant and the potential implications of these findings are discussed.Item Experiences in Delivering Online CS Teacher Professional Development(Association for Computing Machinery, 2024-03-07) Wilde, Jina; Beltran, Emiliano; Zawatski, Michael J.; Fernandez, Amanda S.; Prasad, Priya V.; Yuen, Timothy T.This paper describes our team's experience in designing and delivering the online teacher professional development (PD) program, Computer Science for San Antonio (CS4SA), aimed at empowering educators with computer science (CS) knowledge to increase Latinx participation in CS and STEM education within a large, urban predominantly Latinx school district in South Texas. This paper highlights the successes, challenges, and lessons learned while facilitating two cohorts of the CS PD through online platforms during the COVID-19 pandemic. As a result of this program, participants recognized the importance of integrating CS into their classroom and becoming advocates for the discipline at the high school level. Additionally, teachers, investigators, and other personnel learned important lessons for enhancing the program's impact through collaboration with district administrators and refinement of the online learning experience.Item In-Cold Exposure to Z-3-Hexenal Provides Protection Against Ongoing Cold Stress in Zea mays(2019-06-11) Engelberth, Marie; Selman, Samantha M.; Engelberth, JurgenGreen leaf volatiles (GLVs), which have mostly been described as providers of protection against insect herbivory and necrotrophic pathogen infections, were recently shown to provide significant fortification against cold stress damage. It was further demonstrated that cold-damaged maize seedlings released a significant amount of GLVs, in particular, Z-3-hexenal (Z-3-HAL). Here, we report that the in-cold treatment of maize seedlings with Z-3-HAL significantly improved cold stress resistance. The transcripts for cold-protective genes were also significantly increased in the Z-3-HAL treated maize seedlings over those found in only cold stressed plants. Consequently, the maize seedlings treated with HAL during cold showed a significantly increased structural integrity, significantly less damage, and increased growth after cold stress, relative to the non-HAL treated maize seedlings. Together, these results demonstrate the protective effect of in-cold treatment with HAL against cold damage, and suggest that the perception of these compounds during cold episodes significantly improves resistance against this abiotic stress.Item Precipitation-Driven Anthropogenic Pollutant Fluctuations Within Standing Water Sources of the Edwards Aquifer Region, Texas(SAGE Publications, 2022-06-26) Love, Cheyenne H.; Laub, Brian G.The objective of this study was to assess the contribution of urban runoff in pollutant delivery to standing water pools within the Edwards Aquifer region of Texas. Grab samples of water were collected weekly over 5 months at one urban pool, one undeveloped pool, and one control pond that received minimal runoff. Samples were tested for nitrates, total dissolved phosphorus, Escherichia coli, and other coliform bacteria. The urban site had higher nitrate, E. coli, and other coliform bacteria concentrations than the undeveloped site. Significant positive linear relationships between weekly antecedent rainfall and both nitrate and E. coli were found at the urban site but not the undeveloped site. Water quality parameters at the control site remained stable, suggesting increases in nitrate and E. coli at the urban site were caused by runoff. Using publicly available data, relationships between water quality and weekly antecedent discharge were tested at 24 additional sites varying in land use. Positive relationships for E. coli were found at several urban sites, supporting runoff as a contributor to bacterial loading. Relationships for nitrate were variable, but all additional sites had flowing water, suggesting a unique response of water quality to urban runoff at the sampled urban pool.Item The Costs of Green Leaf Volatile-Induced Defense Priming: Temporal Diversity in Growth Responses to Mechanical Wounding and Insect Herbivory(2019-01-18) Engelberth, Jurgen; Engelberth, MarieGreen leaf volatiles (GLVs) have long been associated with plant defense responses against insect herbivory. Although some of their biological activities appear to directly affect the attacking herbivore, one of the major functions of GLVs seems to be the priming of these defense responses. This priming is generally considered to impose low costs on the plant should no direct attack happen. Here, we demonstrate that priming of maize seedlings with GLVs is costly for the plants as it results in significantly reduced growth. We further demonstrate that priming very selectively affects growth responses after insect elicitor treatment and mechanical wounding depending on the age and/or the developmental stage of the treated plant. The differential growth response of maize seedlings to treatment with GLVs and subsequent herbivory-related damage sheds new light on the biological activity of these important plant volatile compounds and indicates consequences that go beyond defense.Item Variability in the Capacity to Produce Damage-Induced Aldehyde Green Leaf Volatiles among Different Plant Species Provides Novel Insights into Biosynthetic Diversity(2020-02-06) Engelberth, Jurgen; Engelberth, MarieGreen leaf volatiles (GLVs) are commonly released by plants upon damage, thereby providing volatile signals for other plants to prepare against the major causes of damage, herbivory, pathogen infection, and cold stress. However, while the biosynthesis of these compounds is generally well understood, little is known about the qualities and quantities that are released by different plant species, nor is it known if release patterns can be associated with different clades of plants. Here, we provide a first study describing the damage-induced release of major GLVs by more than 50 plant species. We found major differences in the quantity and quality of those compounds between different plant species ranging from undetectable levels to almost 100 µg per gram fresh weight. We also found major shifts in the composition that correlate directly to the quantity of emitted GLV. However, we did not find any major patterns that would associate specific GLV release with distinct clades of plants.