Biology Commons^™

Phytochrome B Integrates Light And Temperature Signals In Arabidopsis, Martina Legris, Cornelia Klose, E Sethe Burgie, Cecilia Costigliolo Rojas Rojas, Maximiliano Neme, Andreas Hiltbrunner, Philip A. Wigge, Eberhard Schäfer, Richard D. Vierstra, Jorge J. Casal

Biology Faculty Publications & Presentations

Ambient temperature regulates many aspects of plant growth and development, but its sensors are unknown. Here, we demonstrate that the phytochrome B (phyB) photoreceptor participates in temperature perception through its temperature-dependent reversion from the active Pfr state to the inactive Pr state. Increased rates of thermal reversion upon exposing Arabidopsis seedlings to warm environments reduce both the abundance of the biologically active Pfr-Pfr dimer pool of phyB and the size of the associated nuclear bodies, even in daylight. Mathematical analysis of stem growth for seedlings expressing wild-type phyB or thermally stable variants under various combinations of light and temperature revealed …

The Variation Of Productivity And Its Allocation Along A Tropical Elevation Gradient: A Whole Carbon Budget Perspective, Yadvinder Malhi, Cécile A. J. Girardin, Gregory R. Goldsmith, Christopher E. Doughty, Norma Salinas, Daniel B. Metcalfe, Walter Huaraca Huasco, Javier E. Silva-Espejo, Jhon Del Aguilla-Pasquell, Filio Farfán Amézquita, Luiz E.O.C. Aragão, Rossella Guerrieri, Françoise Yoko Ishida, Nur Bahar, William Farfan-Rios, Oliver L. Phillips, Patrick Meir, Miles Silman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

• Why do forest productivity and biomass decline with elevation? To address this question, research to date generally has focused on correlative approaches describing changes in woody growth and biomass with elevation.
  
  
• We present a novel, mechanistic approach to this question by quantifying the autotrophic carbon budget in 16 forest plots along a 3300 m elevation transect in Peru.
  
  
• Low growth rates at high elevations appear primarily driven by low gross primary productivity (GPP), with little shift in either carbon use efficiency (CUE) or allocation of net primary productivity (NPP) between wood, fine roots and canopy. The lack of trend in …

Paradoxical Acclimation Responses In The Thermal Performance Of Insect Immunity., Laura V Ferguson, David E Heinrichs, Brent J Sinclair

Biology Publications

Winter is accompanied by multiple stressors, and the interactions between cold and pathogen stress potentially determine the overwintering success of insects. Thus, it is necessary to explore the thermal performance of the insect immune system. We cold-acclimated spring field crickets, Gryllus veletis, to 6 °C for 7 days and measured the thermal performance of potential (lysozyme and phenoloxidase activity) and realised (bacterial clearance and melanisation) immune responses. Cold acclimation decreased the critical thermal minimum from -0.5 ± 0.25 to -2.1 ± 0.18 °C, and chill coma recovery time after 72 h at -2 °C from 16.8 ± 4.9 to 5.2 …

Paradoxical Acclimation Responses In The Thermal Performance Of Insect Immunity., Laura V Ferguson, David E Heinrichs, Brent J Sinclair

Biology Publications

Winter is accompanied by multiple stressors, and the interactions between cold and pathogen stress potentially determine the overwintering success of insects. Thus, it is necessary to explore the thermal performance of the insect immune system. We cold-acclimated spring field crickets, Gryllus veletis, to 6 °C for 7 days and measured the thermal performance of potential (lysozyme and phenoloxidase activity) and realised (bacterial clearance and melanisation) immune responses. Cold acclimation decreased the critical thermal minimum from -0.5 ± 0.25 to -2.1 ± 0.18 °C, and chill coma recovery time after 72 h at -2 °C from 16.8 ± 4.9 to 5.2 …

Depression In Thermal Performance Of Age-Structured Spirodela Polyrhiza Due To The Presence Of Rhopalosiphum Nymphaeae, Mitchell Matis, Chad Brassil, Colby J. Tanner

UCARE Research Products

Thermal performance curves are keys components of population ecology. We performed this study to determine the effects of aphids on duckweed age-structured models across temperature. Results show a depression in birth rates and maturation of rates of duckweed in the presence of aphids. Regression analysis shows that this depression in maturation and birth is directly proportional to aphid growth rates across temperatures. This hints of the idea of modeling duckweed and aphid growth via nested thermal performance curves.

Dynamics And Thermal Sensitivity Of Ballistic And Non-Ballistic Feeding In Salamanders, Stephen M, Deban, Jeffrey A. Scales

Integrative Biology Faculty and Staff Publications

Low temperature reduces the performance of muscle-powered movements, but in movements powered by elastic recoil mechanisms, this effect can be mitigated and performance can be increased. To better understand the morphological basis of high performance and thermal robustness of elastically powered movements, we compared feeding dynamics at a range of temperatures (5-25°C) in two species of terrestrial plethodontid salamanders, Plethodon metcalfi and Ensatina eschscholtzii, which differ in tongue muscle architecture and the mechanism of tongue projection. We found that Ensatina is capable of ballistic projection with a mean muscle mass-specific power of 2100 W kg(-1), revealing an elastic mechanism. Plethodon, …

Optogenetic Stimulation Of Drosophila Heart Rate At Different Temperatures And Ca2+ Concentrations, Yuechen Zhu, Henry Uradu, Zana R. Majeed, Robin L. Cooper

Biology Faculty Publications

Optogenetics is a revolutionary technique that enables noninvasive activation of electrically excitable cells. In mammals, heart rate has traditionally been modulated with pharmacological agents or direct stimulation of cardiac tissue with electrodes. However, implanted wires have been known to cause physical damage and damage from electrical currents. Here, we describe a proof of concept to optically drive cardiac function in a model organism, Drosophila melanogaster. We expressed the light sensitive channelrhodopsin protein ChR2.XXL in larval Drosophila hearts and examined light‐induced activation of cardiac tissue. After demonstrating optical stimulation of larval heart rate, the approach was tested at low temperature …

Similar Metabolic Rate-Temperature Relationships After Acclimation At Constant And Fluctuating Temperatures In Caterpillars Of A Sub-Antarctic Moth., Steven L Chown, Tanya M Haupt, Brent J Sinclair

Biology Publications

Temperature compensation in whole-animal metabolic rate is one of the responses thought, controversially, to characterize insects from low temperature environments. Temperature compensation may either involve a change in absolute values of metabolic rates or a change in the slope of the metabolic rate - temperature relationship. Moreover, assessments of compensation may be complicated by animal responses to fluctuating temperatures. Here we examined whole animal metabolic rates, at 0 °C, 5 °C, 10 °C and 15 °C, in caterpillars of the sub-Antarctic moth, Pringleophaga marioni Viette (Tineidae), following one week acclimations to 5 °C, 10 °C and 15 °C, and fluctuating …

Human Gut Bacteria Are Sensitive To Melatonin And Express Endogenous Circadian Rhythmicity, Jiffin K. Paulose, John M. Wright, Akruti G. Patel, Vincent M. Cassone

Biology Faculty Publications

Circadian rhythms are fundamental properties of most eukaryotes, but evidence of biological clocks that drive these rhythms in prokaryotes has been restricted to Cyanobacteria. In vertebrates, the gastrointestinal system expresses circadian patterns of gene expression, motility and secretion in vivo and in vitro, and recent studies suggest that the enteric microbiome is regulated by the host’s circadian clock. However, it is not clear how the host’s clock regulates the microbiome. Here, we demonstrate at least one species of commensal bacterium from the human gastrointestinal system, Enterobacter aerogenes, is sensitive to the neurohormone melatonin, which is secreted into the …