• Correlation of Electrophysiological and Gene Transcriptional Dysfunctions in Single Cortical Parvalbumin Neurons After Noise Trauma

  Wang, Weihua; Deng, Di; Jenkins, Kyle; Zinsmaier, Alexander K.; Zhou, Qiang; Bao, Shaowen; Department of Physiology, College of Medicine, University of Arizona; Department of Ecology & Evolutionary Biology, University of Arizona (Elsevier BV, 2022-02)

  Parvalbumin-expressing (PV+) interneurons in the sensory cortex form powerful inhibitory synapses on the perisomatic compartments and axon initial segments of excitatory principal neurons (PNs), and perform diverse computational functions. Impaired PV+ interneuron functions have been reported in neural developmental and degenerative disorders. Expression of the unique marker parvalbumin (PV) is often used as a proxy of PV+ interneuron functions. However, it is not entirely clear how PV expression is correlated with PV+ interneuron properties such as spike firing and synaptic transmission. To address this question, we characterized electrophysiological properties of PV+ interneurons in the primary auditory cortex (AI) using whole-cell patch clamp recording, and analyzed the expression of several genes in samples collected from single neurons using the patch pipettes. We found that, after noise induced hearing loss (NIHL), the spike frequency adaptation increased, and the expression of PV, glutamate decarboxylase 67 (GAD67) and Shaw-like potassium channel (KV3.1) decreased in PV+ neurons. In samples prepared from the auditory cortical tissue, the mRNA levels of the target genes were all pairwise correlated. At the single neuron level, however, the expression of PV was significantly correlated with the expression of GAD67, but not KV3.1, maximal spike frequency, or spike frequency adaptation. The expression of KV3.1 was correlated with spike frequency adaptation, but not with the expression of GAD67. These results suggest separate transcriptional regulations of PV/GAD67 vs. KV3.1, both of which are modulated by NIHL.
• "Did You Leave the Wire in?" A Striking Case of Linear Pulmonary Cement Embolism

  Rao, Shishir; Chopra, Madhav; Puthalapattu, Swathy; Department of Medicine, Critical Care Medicine, University of Arizona; Division of Pulmonary, Critical Care Medicine, University of Arizona (American Thoracic Society, 2021)
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  Transformational ecology and climate change

  Jackson, Stephen T.; Department of Geosciences, University of Arizona (American Association for the Advancement of Science (AAAS), 2021-09-03)
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  Managing for RADical ecosystem change: applying the Resist‐Accept‐Direct (RAD) framework

  Lynch, Abigail J; Thompson, Laura M; Beever, Erik A; Cole, David N; Engman, Augustin C; Hawkins Hoffman, Cat; Jackson, Stephen T; Krabbenhoft, Trevor J; Lawrence, David J; Limpinsel, Douglas; et al. (Wiley, 2021-07-08)

  Ecosystem transformation involves the emergence of persistent ecological or social–ecological systems that diverge, dramatically and irreversibly, from prior ecosystem structure and function. Such transformations are occurring at increasing rates across the planet in response to changes in climate, land use, and other factors. Consequently, a dynamic view of ecosystem processes that accommodates rapid, irreversible change will be critical for effectively conserving fish, wildlife, and other natural resources, and maintaining ecosystem services. However, managing ecosystems toward states with novel structure and function is an inherently unpredictable and difficult task. Managers navigating ecosystem transformation can benefit from considering broader objectives, beyond a traditional focus on resisting ecosystem change, by also considering whether accepting inevitable change or directing it along some desirable pathway is more feasible (that is, practical and appropriate) under some circumstances (the RAD framework). By explicitly acknowledging transformation and implementing an iterative RAD approach, natural resource managers can be deliberate and strategic in addressing profound ecosystem change.
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  More than one way to kill a spruce forest: The role of fire and climate in the late‐glacial termination of spruce woodlands across the southern Great Lakes

  Jensen, Allison M.; Fastovich, David; Watson, Ben I.; Gill, Jacquelyn L.; Jackson, Stephen T.; Russell, James M.; Bevington, Joseph; Hayes, Katherine; Lininger, Katherine B.; Rubbelke, Claire; et al. (Wiley, 2020-11)

  In the southern Great Lakes Region, North America, between 19,000 and 8,000 years ago, temperatures rose by 2.5-6.5 degrees C and spruce Picea forests/woodlands were replaced by mixed-deciduous or pine Pinus forests. The demise of Picea forests/woodlands during the last deglaciation offers a model system for studying how changing climate and disturbance regimes interact to trigger declines of dominant species and vegetation-type conversions. The role of rising temperatures in driving the regional demise of Picea forests/woodlands is widely accepted, but the role of fire is poorly understood. We studied the effect of changing fire activity on Picea declines and rates of vegetation composition change using fossil pollen and macroscopic charcoal from five high-resolution lake sediment records. The decline of Picea forests/woodlands followed two distinct patterns. At two sites (Stotzel-Leis and Silver Lake), fire activity reached maximum levels during the declines and both charcoal accumulation rates and fire frequency were significantly and positively associated with vegetation composition change rates. At these sites, Picea declined to low levels by 14 kyr BP and was largely replaced by deciduous hardwood taxa like ash Fraxinus, hop-hornbeam/hornbeam Ostrya/Carpinus and elm Ulmus. However, this ecosystem transition was reversible, as Picea re-established at lower abundances during the Younger Dryas. At the other three sites, there was no statistical relationship between charcoal accumulation and vegetation composition change rates, though fire frequency was a significant predictor of rates of vegetation change at Appleman Lake and Triangle Lake Bog. At these sites, Picea declined gradually over several thousand years, was replaced by deciduous hardwoods and high levels of Pinus and did not re-establish during the Younger Dryas. Synthesis. Fire does not appear to have been necessary for the climate-driven loss of Picea woodlands during the last deglaciation, but increased fire frequency accelerated the decline of Picea in some areas by clearing the way for thermophilous deciduous hardwood taxa. Hence, warming and intensified fire regimes likely interacted in the past to cause abrupt losses of coniferous forests and could again in the coming decades.

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