Biology Commons^™

A Double-Edged Sword? Liana Wood Decomposes Faster Than Tree Wood, Denis Mburu Njoroge, Aphrodis Munyaneza, Juan Zuo, Gbadamassi G. O. Dossa, Douglas Schaefer, Rhett D. Harrison, Stefan A. Schnitzer, J. Hans C. Cornelissen

Biological Sciences Faculty Research and Publications

Lianas are increasing in many forests and show higher stem turnover rates and different chemical profiles compared with trees. However, liana deadwood decomposition dynamics have been overlooked. We redress this omission and hypothesize that liana wood decomposes faster than tree wood due to its larger vessels and higher nutrient content than trees, resulting in greater activity of both microbial and invertebrate decomposers. We tested this hypothesis in a common-garden decomposition experiment with deadwood of two size classes (2.5 and 4 cm diameter) belonging to 12 liana and 12 tree species in tropical China. Liana wood decomposed 28.6% faster than tree …

Editorial: Cellular Contributors And Consequences Of Protein Misfolding And Aggregation, Anoop Arunagiri, Emily M. Sontag, Verena Kohler, Arunkumar Venkatesan

Biological Sciences Faculty Research and Publications

No abstract provided.

Divergent Genetic Architecture Of Cold Stress Tolerance In Aus And Tropical Japonica Rice, Georgia C. Eizenga, Yami Santamaria, Aaron K. Jackson, Huy Phan, Melissa H. Jia, Quynh P.-H. Grunden, Jeremy D. Edwards, Ed Himelblau, Michael Schläppi

Biological Sciences Faculty Research and Publications

Introduction: 

Exploring natural genetic variation to facilitate breeding of improved rice seedling cold tolerance will allow the crop to be planted earlier in the growing season, taking advantage of spring rainfall and decreasing exposure to high summer nighttime temperatures, which reduce grain quality.

Methods: 

To uncover genomic regions in rice that manage cold stress tolerance response mechanisms in the cold-sensitive aus (AUS) and the relatively cold-tolerant tropical japonica (TRJ) subpopulations, and to identify cold tolerance genes, AUS and TRJ recombinant inbred line populations developed from crosses between cold-tolerant and cold-sensitive parents were used for quantitative trait locus (QTL) mapping of …

Consumers Stabilize Grassland Ecosystem Functions By Destabilizing Belowground Communities Under Abiotic Stress, Jane M. Lucas, Michelle L. Budny, Nathan P. Lemoine

Biological Sciences Faculty Research and Publications

Consumers play a critical role in mediating plant and ecosystem responses to abiotic stress, yet their influence on belowground processes under changing environmental conditions remains underexplored. Insect consumers are vital components of grassland ecosystems that can shape ecosystem function and stability by mitigating how plant and microbial communities respond to abiotic stress, like drought. This study investigates how small-bodied consumers influence the magnitude and stability of grassland belowground functions across gradients of abiotic stress. We conducted a fully factorial field experiment manipulating consumer presence and induced drought over a growing season. Our results reveal that the presence of consumers stabilizes …

Biophysical Processes Of Morphogenesis In Lizard Lungs, Kaleb Hill, Aaron H. Griffing, Michael A. Palmer, Bezia Lemma, Aria S. Lupo, Tony Gamble, Natalia A. Shylo, Andrej Kosmrlj, Paul A. Trainor, Celeste M. Nelson

Biological Sciences Faculty Research and Publications

Background

The lungs of squamate reptiles (lizards and snakes) are highly diverse, exhibiting single chambers, multiple chambers, transitional forms with two to three chambers, along with a suite of other anatomical features, including finger-like epithelial projections into the body cavity known as diverticulae. During embryonic development of the simple, sac-like lungs of anoles, the epithelium is pushed through the openings of a pulmonary smooth muscle mesh by the forces of luminal fluid pressure. This process of stress ball morphogenesis generates the faveolar epithelium typical of squamate lungs.

Results

Here, we compared embryonic lung development in brown anoles, leopard geckos, and …

Does Increasing Canopy Liana Density Decrease The Tropical Forest Carbon Sink?, Stefan A. Schnitzer, David M. Defilippis

Biological Sciences Faculty Research and Publications

The ongoing decline in the American tropical forest carbon sink has serious ramifications for atmospheric carbon levels and global climate change. Increasing liana abundance may explain the decaying carbon sink because lianas reduce canopy tree growth and survival, which limits forest carbon storage. However, canopy lianas, not solely understory lianas, would have to be increasing for this hypothesis to be credible because canopy lianas compete especially intensely with canopy trees. We examined the change in canopy lianas over 10 years on Barro Colorado Island (BCI), Panama to test two main hypotheses. (1) Canopy lianas are increasing on BCI. (2) Increasing …

Hcmv Infection Of Terminally Differentiated Neurons Disrupts Microtubule Organization, Resulting In Neurite Retraction, Jacob W. Adelman, Andrew T. Sukowaty, Kaitlyn J. Partridge, Jessica E. Gawrys, Allison Akins, Scott S. Terhune, Allison D. Ebert

Biological Sciences Faculty Research and Publications

Human cytomegalovirus (HCMV) is a prolific human herpesvirus that infects most individuals by adulthood. While typically asymptomatic in adults, congenital infection can induce serious neurological symptoms, including hearing loss, visual deficits, cognitive impairment, and microcephaly in 10%–15% of cases. HCMV has been shown to infect most neural cells, with our group recently demonstrating this capacity in stem cell-derived forebrain neurons. Infection of neurons induces deleterious effects on calcium dynamics and electrophysiological function paired with gross restructuring of neuronal morphology. Here, we utilize an induced pluripotent stem cell-derived model of the human forebrain to demonstrate how HCMV infection induces syncytia, drives …

Memories Of Trees Past: Coexistence Implications Of Legacy Conspecific Density Dependence, Lukas J. Magee, Daniel J.B. Smith, David Bauman, Po-Ju Ke, Helene C. Muller-Laudau, Kristina J. Anderson-Teixeira, Jessica Shue, David A. Orwig, Sean M. Mcmahon, Stephanie Bohlman, Raelene M. Crandall, Ben Weinstein, Sergio Marconi, Jeremy W. Lichstein, James F. Gillooly, Robert Bagchi, Joseph A. Lamanna, Daniel J. Johnson

Biological Sciences Faculty Research and Publications

The Janzen-Connell Hypothesis posits that plant species diversity is maintained by a reduction in seedling survival near living conspecific trees relative to heterospecifics–known as negative conspecific density dependence (CDD). CDD facilitates coexistence if stronger than heterospecific density dependence (HDD). However, whether and how long CDD persists after trees die is unknown. In a three-year study across three forests, we monitored seedling survival near living and dead trees, both conspecific and heterospecific, across a seven-year chrono-sequence since tree death. CDD persisted for at least 5 years after tree death (‘legacy CDD’), and most species showed stronger CDD relative to HDD through …

Lianas Reduce Tree Height With Negative Consequences For Carbon Storage And Growth Estimates, Xingyan Cao, Frieke Van Coillie, Sruthi M. Krishna Moorthy, Kasper Coppieters, Barbara D'Hont, Stefan A. Schnitzer, Geertje M. F. Van Der Heijden, Hans Verbeeck, Félicien Meunier

Biological Sciences Faculty Research and Publications

1. Current evidence suggests that liana (woody vine) competition with trees could be threatening the carbon sink by reducing carbon uptake and storage in tropical forests. Previous studies investigating forest demography in liana removal experiments have, however, assumed similar allometries for trees, regardless of the amount of lianas they support. Yet, recent observations suggest that liana load may alter tree shape and structure, including height, which could result in an underestimation of the liana effects on forest carbon stocks and tree growth.
2. In this study, we used terrestrial laser scanning (TLS) in a liana removal experiment in Gigante Peninsula, Panama, collected …

Hsp70 Chaperones, Ssa1 And Ssa2, Limit Poly(A) Binding Protein Aggregation, Hannah E. Buchholz, Sean A. Martin, Jane E. Dorweiler, Claire M. Radtke, Adam S. Knier, Natalia B. Beans, Anita L. Manogaran

Biological Sciences Faculty Research and Publications

Molecular chaperones play a central role in maintaining protein homeostasis. The highly conserved Hsp70 family of chaperones have major functions in folding of nascent peptides, protein refolding, and protein aggregate disassembly. In yeast, loss of two Hsp70 proteins, Ssa1 and Ssa2, is associated with decreased cellular growth and shortened lifespan. While heterologous or mutant temperature-sensitive proteins form anomalous large cytoplasmic inclusions in ssa1Δssa2Δ strains, it is unclear how endogenous wild-type proteins behave and are regulated in the presence of limiting Hsp70s. Using the wild-type yeast Poly A binding protein (Pab1), which is involved in mRNA binding and forms stress granules …

Effects Of Soluble Electron Shuttles On Microbial Iron Reduction And Methanogenesis, Bhim Sen Thapa, Theodore M. Flynn, Zena D. Jensvold, Kenneth M. Kemner, Margaret F. Sladek, Edward J. O'Loughlin, Christopher W. Marshall

Biological Sciences Faculty Research and Publications

In many aquatic and terrestrial ecosystems, iron (Fe) reduction by microorganisms is a key part of biogeochemical cycling and energy flux. The presence of redox-active electron shuttles in the environment potentially enables a phylogenetically diverse group of microbes to use insoluble iron as a terminal electron acceptor. We investigated the impact that different electron shuttles had on respiration, microbial physiology, and microbial ecology. We tested eight different electron shuttles, seven quinones and riboflavin, with redox potentials between 0.217 and −0.340 V. Fe(III) reduction coupled with acetate oxidation was observed with all shuttles. Once Fe(III) reduction began to plateau, a rapid …

Understanding How Chaperones Influence Protein Aggregation, Hannah Buchholz

Dissertations (1934 -)

Cells depend on properly folded proteins to function and remain healthy. If proteins adopt a nonnative conformation, they may have an increased propensity to clump together or aggregate, which can compromise cell viability. Unwanted aggregates are linked to a class of diseases called proteinopathies, which include fatal disorders such as Alzheimer’s disease and amyotrophic lateral sclerosis (ALS). Fortunately, cellular factors, known as molecular chaperones, help maintain protein homeostasis by limiting and disassembling protein aggregates. However, the mechanisms that underlie how chaperones modify protein aggregation are poorly understood. The goal of this dissertation is to explore the molecular mechanisms used by …

When Can We Detect Lianas From Space? Toward A Mechanistic Understanding Of Liana-Infested Forest Optics, Stefan A. Schnitzer

Biological Sciences Faculty Research and Publications

Lianas, woody vines acting as structural parasites of trees, have profound effects on the composition and structure of tropical forests, impacting tree growth, mortality, and forest succession. Remote sensing could offer a powerful tool for quantifying the scale of liana infestation, provided the availability of robust detection methods. We analyze the consistency and global geographic specificity of spectral signals—reflectance across wavelengths—from liana-infested tree crowns and forest stands, examining the underlying mechanisms of these signals. We compiled a uniquely comprehensive database, including leaf reflectance spectra from 5424 leaves, fine-scale airborne reflectance data from 999 liana-infested canopies, and coarse-scale satellite reflectance data …

Local Stabilising Density Effects In The Context Of Ecological Disturbance And Community Assembly, Cole J. Doolittle, Joseph A. Lamanna

Biological Sciences Faculty Research and Publications

The maintenance of species diversity in ecological communities has many promising explanations, including certain types of local biotic interactions that generate differential effects on the performance of conspecific and heterospecific individuals. To date, most studies of these local biotic interactions have focused on relatively stable systems, such as mature forests or undisturbed grasslands. However, many ecosystems are far from a stable state, especially under accelerating global climate change. Here, we present a synthesis of local differences between conspecific and heterospecific interactions following disturbances—and how disturbances may alter the strength and scaling of these effects to population growth and species diversity. …

The Influence Of Historical Climate Cycles On The Diversification And Demography Of Species From The Neotropical Lizard Group Anolis Chrysolepis, Tony Gamble

Biological Sciences Faculty Research and Publications

Historical shifts in climate have significantly influenced the establishment of ecosystems and the evolution of species. Phylogeographical studies integrated with niche modelling can provide insights into divergence events and demography. This study explores the evolutionary history, demographic patterns, and spatiotemporal dynamics of seven South American lizard species of the Anolis chrysolepis species group, which has been proposed to be strongly impacted by Pleistocene climatic fluctuations under the Refugia Hypothesis. We utilized mitochondrial and nuclear DNA sequences to delineate lineages, estimate divergence times, and examine demographic dynamics. Ecological niche models were employed to assess historical range shifts and identify climatic stability …

Frequency-Dependent Assembly Processes Determine The Coexistence And Relative Abundance Of Tropical Plant Species, David M. Defilippis, Joseph A. Lamanna, Stefan A. Schnitzer

Biological Sciences Faculty Research and Publications

Testing the extent to which ecological communities are structured by deterministic (niche-based) assembly processes, resulting in predictable species abundance and composition, is a fundamental goal of ecology. Here we use a 10-year dataset of 55,156 lianas comprising 86 species in an old-growth tropical forest in Panama to test whether community assembly is consistent with niche-based assembly processes. We find that species diversity and community composition was maintained because species conformed to four general requirements of coexistence theory: (1) species have negative conspecific frequency-dependent feedback that control their local population size; (2) species have a stronger negative effect on their own …

The Mc4r Agonist, Setmelanotide, Is Associated With An Improvement In Hypercapnic Chemosensitivity And Weight Loss In Male Mice, Sarah N. Framnes-Deboer, Deanna M. Arble, Athena Rivera

Biological Sciences Faculty Research and Publications

Obesity increases the risk of respiratory diseases that reduce respiratory chemosensitivity, such as Obesity Hypoventilation Syndrome and sleep apnea. Recent evidence suggests that obesity-related changes in the brain, including alterations in melanocortin signaling via the melanocortin-4 receptor (MC4R), may underly altered chemosensitivity. Setmelanotide, an MC4R agonist, causes weight loss in both humans and animal models. However, it is unknown the extent to which setmelanotide affects respiratory chemosensitivity independent of body weight loss. The present study uses diet-induced obese, male C57bl/6 J mice to determine the extent to which acute setmelanotide treatment affects the hypercapnic ventilatory response (HCVR). We find that …

Hydrolysis Of The Acetyl-Coa Allosteric Activator By Staphylococcus Aureus Pyruvate Carboxylase, Amanda J. Laseke, Jeremy R. Lohman, Martin St. Maurice

Biological Sciences Faculty Research and Publications

Pyruvate carboxylase (PC) catalyzes the carboxylation of pyruvate to oxaloacetate which serves as an important anaplerotic reaction to replenish citric acid cycle intermediates. In most organisms, the PC-catalyzed reaction is allosterically activated by acetyl-coenzyme A. It has previously been reported that vertebrate PC can catalyze the hydrolysis of acetyl-CoA, offering a potential means for the enzyme to attenuate its allosteric activation. However, in the years since this initial report, there has been no further investigation of this phenomenon. The allosteric binding site for acetyl-CoA is now well characterized, enabling more detailed studies on acetyl-CoA hydrolysis at the allosteric site. Here, …

Identification Of Diverse Bacteriophages Associated With Bees And Hoverflies, Rohan A. Bandoo, Simona Kraberger, Cahit Ozturk, Michael C. Lund, Qiyun Zhu, Chelsea N. Cook, Brian Smith, Arvind Varsani

Biological Sciences Faculty Research and Publications

Bacteriophages are the most numerous, ubiquitous, and diverse biological entities on the planet. Prior studies have identified bacteriophages associated with pathogenic and commensal microbiota of honeybees. In this study we expand on what is known about bacteriophages from the lineages Caudoviricetes, Inoviridae, and Microviridae, which are associated with honeybees (Apidae, Apis mellifera), solitary bees of the genus Nomia (Halictidae, Nomia), and hoverflies (Syrphidae). The complete genomes of seven caudoviruses, seven inoviruses, and 288 microviruses were assembled from honeybees (n = 286) and hoverflies in Arizona (n = 2). We used bacterial host predictive …

Elephant Megacarcasses Increase Local Nutrient Pools In African Savanna Soils And Plants, Courtney G. Reed, Michelle L. Budny, Johan T. Du Toit, Ryan Helcoski, Joshua P. Schimel, Izak P.J. Smit, Tercia Strydom, Aimee Tallian, Dave I. Thompson, Helga Van Coller, Nathan P. Lemoine, Deron E. Burkepile

Biological Sciences Faculty Research and Publications

African elephants (Loxodonta africana) are the largest extant terrestrial mammals, with bodies containing enormous quantities of nutrients. Yet, we know little about how these nutrients move through the ecosystem after an elephant dies. Here, we investigated the initial effects (1–26 months postmortem) of elephant megacarcasses on savanna soil and plant nutrient pools in the Kruger National Park, South Africa. We hypothesized that (H1) elephant megacarcass decomposition would release nutrients into soil, resulting in higher concentrations of soil nitrogen (N), phosphorus (P), and micronutrients near the center of carcass sites; (H2) carbon (C) inputs into the soil would stimulate …

Global Decoupling Of Functional And Phylogenetic Diversity In Plant Communities, Stefan A. Schnitzer

Biological Sciences Faculty Research and Publications

Plant communities are composed of species that differ both in functional traits and evolutionary histories. As species’ functional traits partly result from their individual evolutionary history, we expect the functional diversity of communities to increase with increasing phylogenetic diversity. This expectation has only been tested at local scales and generally for specific growth forms or specific habitat types, for example, grasslands. Here we compare standardized effect sizes for functional and phylogenetic diversity among 1,781,836 vegetation plots using the global sPlot database. In contrast to expectations, we find functional diversity and phylogenetic diversity to be only weakly and negatively correlated, implying …

Diabetes Potentiates The Emergence And Expansion Of Antibiotic Resistance, John C. Shook, Benjamin P. Darwitz, Kaleb J. Tyson, Amanda Z. Velez, Sophia K. Bridwell, Joshua B. Parsons, Sarah E. Rowe, Christopher Marshall, Brian P. Conlon, Lance R. Thurlow

Biological Sciences Faculty Research and Publications

Individuals with diabetes mellitus frequently develop severe skin and soft tissue infections (SSTIs) that are recalcitrant to antibiotic treatment. We examined how diabetes affects the emergence of antibiotic resistance in a Staphylococcus aureus SSTI. We determined that S. aureus evolves antibiotic resistance rapidly in diabetic mice, while resistance did not occur in nondiabetic mice over the course of infection. Diabetes-associated immune cell dysfunction plays a minor role in the emergence of resistance, while hyperglycemia plays a dominant role facilitating the expansion and takeover of resistant mutants in diabetic infections. Furthermore, vancomycin intermediate resistant isolates display a pronounced fitness defect in …

The Rad6-Like Ubiquitin Conjugase Gene Osubc7 Has A Positive Role In The Early Cold Stress Tolerance Response Of Rice, Huy Phan, Michael Schläppi

Biological Sciences Faculty Research and Publications

Background/Objectives: Cold stress poses a significant threat to Asian rice cultivation, disrupting important physiological processes crucial for seedling establishment and overall plant growth. It is, thus, crucial to elucidate genetic pathways involved in cold stress tolerance response mechanisms. Methods: We mapped OsUBC7, a Radiation-sensitive 6 (RAD6)-type homolog of rice, to a low-temperature seedling survivability (LTSS) QTL and used genomics, molecular genetics, and physiological assays to assess its role in plant resilience against low-temperature stress. Results: OsUBC7 is cold responsive and has higher expression levels in cold-tolerant japonica than cold-sensitive indica. Overexpression of OsUBC7 enhances LTSS of indica and freezing tolerance …

Editorial: Women In Antimicrobials, Resistance And Chemotherapy: 2023, Cindy Shuan Ju Teh, Krassimira R. Hristova, Ana R. Freitas

Biological Sciences Faculty Research and Publications

No abstract provided.

Loss Of Endogenous Circadian Clock Function In Mice Alters Respiratory Cycle Timing In A Time Of Day- And Sex-Specific Manner, Aaron A. Jones, Deanna M. Arble

Biological Sciences Faculty Research and Publications

Resting breathing and ventilatory chemoreflexes are regulated in a 24-hr manner by the endogenous circadian clock. However, it is unclear how circadian biology influences different phases of the breath-to-breath respiratory cycle which are predominantly controlled by pontomedullary regions of the brainstem. Here, we performed whole-body plethysmography during quiet wakefulness in young adult male and female mice lacking the core clock gene Brain and Muscle Arnt-like 1 (BMAL1) to determine the extent to which the molecular clock affects respiratory cycle timing and ventilatory airflow mechanics. Breath waveform analysis revealed that male BMAL1 knockout (KO) mice exhibit time of day-specific differences in …

Long-Term Increases In Wing Length Occur Independently Of Changes In Climate And Climate-Driven Shifts In Body Size, Tiffany Dias, Nathan P. Lemoine, Scott W. Yanco, Marketa Zimova, Rachael A. Bay, Brian C. Weeks

Biological Sciences Faculty Research and Publications

Recent widespread reductions in body size across species have been linked to increasing temperatures; simultaneous increases in wing length relative to body size have been broadly observed but remain unexplained. Size and shape may change independently of one another, or these morphological shifts may be linked, with body size mediating or directly driving the degree to which shape changes. Using hierarchical Bayesian models and a morphological time series of 27 366 specimens from five North American migratory passerine bird species, we tested the roles that climate and body size have played in shifting wing length allometry over four decades. We …

Cumulative Effects Of H+ And PI On Force And Power Of Skeletal Muscle Fibres From Young And Older Adults, Christopher W. Sundberg, Laura E. Teigen, Sandra K. Hunter, Robert H. Fitts

Biological Sciences Faculty Research and Publications

The cellular causes of the age-related loss in power output and increased fatigability are unresolved. We previously observed that the depressive effects of hydrogen (H+) (pH 6.2) and inorganic phosphate (Pi) (30 mm) did not differ in muscle fibres from young and older men. However, the effects may have been saturated in the severe fatigue-mimicking condition, potentially masking age differences in the sensitivity of the cross-bridge to these metabolites. Thus, we compared the contractile mechanics of muscle fibres from the vastus lateralis of 13 young (20–32 years, seven women) and 12 older adults (70–90 years, six women) in conditions mimicking …

Environmental Light Controls The Daily Organization Of Breathing By Activating Brn3b-Expressing Intrinsically Photosensitive Retinal Ganglion Cells In Mice, Aaron A. Jones, Allison R. Spears, Deanna M. Arble

Biological Sciences Faculty Research and Publications

Rhythmic, daily fluctuations in minute ventilation are controlled by the endogenous circadian clock located in the suprachiasmatic nucleus (SCN). While light serves as a potent synchronizer for the SCN, it also influences physiology and behavior by activating Brn3b-expressing, intrinsically photosensitive retinal ganglion cells (ipRGCs). It is currently unclear the extent to which the external light environment shapes daily ventilatory patterns independent of the SCN. To determine the relative influence of environmental light versus circadian timing on the organization of daily rhythms in minute ventilation, we used whole-body plethysmography to measure the breathing of mice housed on a non-entraining T28 cycle …

Toe Pad Morphology And Adhesion In The Miniaturized Gecko, Chatogekko Amazonicus (Gekkota: Sphaerodactylidae), Aaron H. Griffing, Juan D. Daza, Stuart V. Nielsen, Fernanda P. Werneck, Patrik F. Viana, Tony Gamble

Biological Sciences Faculty Research and Publications

Chatogekko amazonicus is a miniaturized gecko from northern South America and is among the smallest of toe pad bearing lizards. The toe pads of C. amazonicus are miniscule, between 18% and 27% of the plantar surface area. We aimed to investigate the relationship between adhesive toe pad morphology, body size, and adhesive capabilities. Using scanning electron microscopy, we determine that the adhesive pads of C. amazonicus exhibit branched setae similar to those of other geckos, but that are generally much smaller. When compared with other gecko taxa, we show that C. amazonicus setae occupy a similar range of seta length: …

Role Of Male Gonad-Enriched Micrornas In Sperm Production In Caenorhabditis Elegans, Lu Lu, Allison L. Abbott

Biological Sciences Faculty Research and Publications

Germ cell development and gamete production in animals require small RNA pathways. While studies indicate that microRNAs (miRNAs) are necessary for normal sperm production and function, the specific roles for individual miRNAs are largely unknown. Here, we use small RNA sequencing (RNA-seq) of dissected gonads and functional analysis of new loss-of-function alleles to identify functions for miRNAs in the control of fecundity and sperm production in Caenorhabditis elegans males and hermaphrodites. We describe a set of 29 male gonad-enriched miRNAs and identify a set of individual miRNAs (mir-58.1 and mir-235) and a miRNA cluster (mir-4807-4810.1) that …