Biology Commons^™

Draft Genome Sequence Of Staphylococcus Succinus Strain Gn1, Isolated From A Basement Floor In Milwaukee, Wi, Grant P. Nickolson, Nasim Maghboli Balasjin, Christopher Marshall

Biological Sciences Faculty Research and Publications

A strain of Staphylococcus succinus was sampled from the floor of the basement of a house and isolated in an undergraduate classroom in Milwaukee, WI. Here, we report the draft genome sequence of this strain.

Lianas Have More Acquisitive Traits Than Trees In A Dry But Not In A Wet Forest, Jose A. Medina-Vega, Frans Bongers, Lourens Poorter, Stefan A. Schnitzer, Frank J. Sterck

Biological Sciences Faculty Research and Publications

1. Lianas are increasing in relative abundance and biomass in many tropical forests. We tested the hypothesis that lianas conform to the fast and acquisitive end of the continuum of plant strategies, allowing lianas to acquire resources faster than trees.
2. We assessed functional traits representative of the leaf (LES) and wood economics spectrum (WES), including plant hydraulics, in 16 liana and 16 tree species in the canopy of two tropical forests at the extremes of the climatic and geological gradient across the Isthmus of Panama.
3. For both forests, we observed a trade-off between the construction of more productive leaves with rapid …

Lianas Do Not Reudce Tree Biomass Accumulation In Young Successional Tripical Dry Forests, Sergio Estrada Villegas, Jefferson S. Hall, Michiel Van Breugel, Stefan A. Schnitzer

Biological Sciences Faculty Research and Publications

Young successional tropical forests are crucial in the global carbon cycle because they can quickly sequester large quantities of atmospheric carbon. However, lianas (woody vines) can significantly decrease biomass accumulation in young regenerating forests. Lianas are abundant in tropical dry forests, and thus we hypothesized that lianas reduce biomass accretion in dry forests. Lianas may be particularly detrimental to the growth of young trees, which are vulnerable to competition from lianas. Alternatively, lianas may have a stronger negative effect on the largest trees because lianas seek the high-light environment at the top of the forest canopy. We tested these hypotheses …

A Graphical Null Model For Scaling Biodiversity–Ecosystem Functioning Relationships, Kathryn E. Barry, Gabriella A. Pinter, Joseph W. Strini, Karrisa Yang, Istvan G. Lauko, Stefan A. Schnitzer, Adam T. Clark, Jane Cowles, Akira S. Mori, Laura Williams, Peter B. Reich, Alexandra J. Wright

Biological Sciences Faculty Research and Publications

1. Global biodiversity is declining at rates faster than at any other point in human history. Experimental manipulations at small spatial scales have demonstrated that communities with fewer species consistently produce less biomass than higher diversity communities. Understanding the consequences of the global extinction crisis for ecosystem functioning requires understanding how local experimental results are likely to change with increasing spatial and temporal scales and from experiments to naturally assembled systems.
2. Scaling across time and space in a changing world requires baseline predictions. Here, we provide a graphical null model for area scaling of biodiversity–ecosystem functioning relationships using observed macroecological patterns: …

Unifying Ecosystem Responses To Disturbance Into A Single Statistical Framework, Nathan P. Lemoine

Biological Sciences Faculty Research and Publications

Natural ecosystems are currently experiencing unprecedented rates of anthropogenic disturbance. Given the potential ramifications of more frequent disturbances, it is imperative that we accurately quantify ecosystem responses to severe disturbance. Specifically, ecologists and managers need estimates of resistance and recovery from disturbance that are free of observation error, not biased by temporal stochasticity and that standardize disturbance magnitude among many disparate ecosystems relative to normal interannual variability. Here, I propose a statistical framework that estimates all four components of ecosystem responses to disturbance (resistance, recovery, elasticity and return time), while resolving all of the issues described above. Coupling autoregressive time …

Lianas Explore The Forest Canopy More Effectively Than Trees Under Drier Conditions, Jose A. Medina-Vega, Frans Bongers, Stefan A. Schnitzer, Frank J. Sterck

Biological Sciences Faculty Research and Publications

1. Lianas rely on trees for support and access to high-light positions in the forest canopy, but the implications for how lianas explore the canopy compared to trees remain understudied. We present an in situ forest canopy study to test the hypotheses that: (1) lianas favour leaf display over stem investment compared to trees and (2) lianas have greater potential to colonize non-shaded, high-light areas effectively than trees.
2. We compared branches of 16 liana species with those of 16 sympatric tree species in the canopy of two lowland tropical forests with contrasting rainfall regimes in Panama using 40–50 m tall canopy …

Biotic And Abiotic Drivers Of Plant–Pollinator Community Assembly Across Wildfire Gradients, Joseph A. Lamanna, Laura A. Burkle, R. Travis Belote, Jonathan A. Myers

Biological Sciences Faculty Research and Publications

1. Understanding how abiotic disturbance and biotic interactions determine pollinator and flowering-plant diversity is critically important given global climate change and widespread pollinator declines. To predict responses of pollinators and flowering-plant communities to changes in wildfire disturbance, a mechanistic understanding of how these two trophic levels respond to wildfire severity is needed.
2. We compared site-to-site variation in community composition (β-diversity), species richness and abundances of pollinators and flowering plants among landscapes with no recent wildfire (unburned), mixed-severity wildfire and high-severity wildfire in three sites across the Northern Rockies Ecoregion, USA. We used variation partitioning to assess the relative contributions …

Sex Chromosome Turnover In Bent-Toed Geckos (Cyrtodactylus), Shannon E. Keating, Madison Blumer, L. Lee Grismer, Aung Lin, Stuart V. Nielsen, Myint Kyaw Thura, Perry L. Wood Jr., Evan S.H. Quah, Tony Gamble

Biological Sciences Faculty Research and Publications

Lizards and snakes (squamates) are known for their varied sex determining systems, and gecko lizards are especially diverse, having evolved sex chromosomes independently multiple times. While sex chromosomes frequently turnover among gecko genera, intrageneric turnovers are known only from Gekko and Hemidactylus. Here, we used RADseq to identify sex-specific markers in two species of Burmese bent-toed geckos. We uncovered XX/XY sex chromosomes in Cyrtodactylus chaunghanakwaensis and ZZ/ZW sex chromosomes in Cyrtodactylus pharbaungensis. This is the third instance of intrageneric turnover of sex chromosomes in geckos. Additionally, Cyrtodactylus are closely related to another genus with intrageneric turnover, Hemidactylus. …

Unraveling The Relative Role Of Light And Water Competition Between Lianas And Trees In Tropical Forests: A Vegetation Model Analysis, Félicien Meunier, Hans Verbeeck, Betsy Cowdery, Stefan A. Schnitzer, Chris M. Smith-Martin, Jennifer S. Powers, Xiangtao Xu, Martijn Slot, Hannes P.T. De Deurwaerder, Matteo Detto, Damien Bonal, Marcos Longo, Louis S. Santiago, Michael Dietze

Biological Sciences Faculty Research and Publications

1. Despite their low contribution to forest carbon stocks, lianas (woody vines) play an important role in the carbon dynamics of tropical forests. As structural parasites, they hinder tree survival, growth and fecundity; hence, they negatively impact net ecosystem productivity and long-term carbon sequestration.
2. Competition (for water and light) drives various forest processes and depends on the local abundance of resources over time. However, evaluating the relative role of resource availability on the interactions between lianas and trees from empirical observations is particularly challenging. Previous approaches have used labour-intensive and ecosystem-scale manipulation experiments, which are infeasible in most situations.
3. We propose …

Sperm Fate Is Promoted By The Mir-44 Microrna Family In The Caenorhabditis Elegans Hermaphrodite Germline, Katherine Ann Maniates, Benjamin S. Olson, Allison L. Abbott

Biological Sciences Faculty Research and Publications

Posttranscriptional regulation of gene expression, typically effected by RNA-binding proteins, microRNAs (miRNAs), and translation initiation factors, is essential for normal germ cell function. Numerous miRNAs have been detected in the germline; however, the functions of specific miRNAs remain largely unknown. Functions of miRNAs have been difficult to determine as miRNAs often modestly repress target mRNAs and are suggested to sculpt or fine tune gene expression to allow for the robust expression of cell fates. In Caenorhabditis elegans hermaphrodites, cell fate decisions are made for germline sex determination during larval development when sperm are generated in a short window before the …

Early Olfactory, But Not Gustatory Processing, Is Affected By The Selection Of Heritable Cognitive Phenotypes In Honey Bee, Meghan M. Bennett, Chelsea N. Cook, Brian H. Smith, Hong Lei

Biological Sciences Faculty Research and Publications

Associative learning enables animals to predict rewards or punishments by their associations with predictive stimuli, while non-associative learning occurs without reinforcement. The latter includes latent inhibition (LI), whereby animals learn to ignore an inconsequential ‘familiar’ stimulus. Individual honey bees display heritable differences in expression of LI. We examined the behavioral and neuronal responses between honey bee genetic lines exhibiting high and low LI. We observed, as in previous studies, that high LI lines learned a familiar odor more slowly than low LI bees. By measuring gustatory responses to sucrose, we determined that perception of sucrose reward was similar between both …

A Comparison Of The Foraging Biology Of Two Tropical Gecko Species In Disturbed Areas, Charles Cummings, Tony Gamble, Michael Wells

Biological Sciences Faculty Research and Publications

The traditional foraging mode dichotomy in lizards has been one of ambush predators vs. wide ranging predators. Each mode has been associated with its own suite of other complementary characteristics, including metabolic rates, sensory capacities, as well as predator and prey species. While foraging mode within lizard families is often consistent, few studies have compared the foraging modes of sympatric members of a clade in which one species is nocturnal and the other diurnal. Hemidactylus frenatus, an introduced, nocturnal house gecko, and Gonatodes albogularis, a native, diurnal species, inhabit disturbed habitats in Costa Rica. Using traditional movement-based indices, moves per …

Improving Collaborations Between Empiricists And Modelers To Advance Grassland Community Dynamics In Ecosystem Models, Kevin R. Wilcox, Kimberly J. Komatsu, Meghan L. Avolio, Nathan P. Lemoine

Biological Sciences Faculty Research and Publications

No abstract provided.

The Response Of Lianas To 20 Yr Of Nutrient Addition In A Panamanian Forest, Stefan A. Schnitzer, Sergio Estrada Villegas, S. Joseph Wright

Biological Sciences Faculty Research and Publications

Over the past two decades, liana density and basal area have been increasing in many tropical forests, which has profound consequences for forest diversity and functioning. One hypothesis to explain increasing lianas is elevated nutrient deposition in tropical forests resulting from fossil fuels, agricultural fertilizer, and biomass burning. We tested this hypothesis by surveying all lianas ≥1 cm in diameter (n = 3,967) in 32 plots in a fully factorial nitrogen (N), phosphorus (P), and potassium (K) addition experiment in a mature tropical forest in central Panama. We conducted the nutrient-addition experiment from 1998 until present and we first …

Lianas Maintain Insectivorous Bird Abundance And Diversity In A Neotropical Forest, Stefan A. Schnitzer, Nicole L. Michel, Jennifer S. Powers, W. Douglas Robinson

Biological Sciences Faculty Research and Publications

The spatial habitat heterogeneity hypothesis posits that habitat complexity increases the abundance and diversity of species. In tropical forests, lianas add substantial habitat heterogeneity and complexity throughout the vertical forest profile, which may maintain animal abundance and diversity. The effects of lianas on tropical animal communities, however, remain poorly understood. We propose that lianas have a positive effect on animals by enhancing habitat complexity. Lianas may have a particularly strong influence on the forest bird community, providing nesting substrate, protection from predators, and nutrition (food). Understory insectivorous birds, which forage for insects that specialize on lianas, may particularly benefit. Alternatively, …

Challenges Facing Young Scientists In Academia And Industry In The United States From The Lens Of A Millennial Academic, Joseph R. Clark

Biological Sciences Faculty Research and Publications

Rising to the challenge: Pictured from left to right: Salma L. Nuñez, Albert Reyes and Lisandra Santiago-Capeles, Ph.D. The challenges that young scientists face in academia and industry in the United States are discussed. Prof. Joseph Clark provides insight about how social media, funding, diversity, natural disasters, COVID-19 and student loan debt are impacting young scientists. A discussion of strategies to meet these challenges and support young scientists are presented.

Multi-Scale 3d Cryo-Correlative Microscopy For Vitrified Cells, Gong-Her Wu, Patrick G. Mitchell, Jesus G. Galaz-Montoya, Corey W. Hecksel, Emily M. Sontag, Vimal Gangadharan, Jeffrey Marshman, David Mankus, Margaret E. Bisher, Abigail K.R. Lytton-Jean, Judith Frydman, Kirk Czymmek, Wah Chiu

Biological Sciences Faculty Research and Publications

Three-dimensional (3D) visualization of vitrified cells can uncover structures of subcellular complexes without chemical fixation or staining. Here, we present a pipeline integrating three imaging modalities to visualize the same specimen at cryogenic temperature at different scales: cryo-fluorescence confocal microscopy, volume cryo-focused ion beam scanning electron microscopy, and transmission cryo-electron tomography. Our proof-of-concept benchmark revealed the 3D distribution of organelles and subcellular structures in whole heat-shocked yeast cells, including the ultrastructure of protein inclusions that recruit fluorescently-labeled chaperone Hsp104. Since our workflow efficiently integrates imaging at three different scales and can be applied to other types of cells, it could …

Temporal Variability In Production Is Not Consistently Affected By Global Change Drivers Across Herbaceous-Dominated Ecosystems, Meghan L. Avolio, Kevin R. Wilcox, Kimberly J. Komatsu, Nathan P. Lemoine, William D. Bowman, Scott L. Collins, Alan K. Knapp, Sally E. Koerner, Melinda D. Smith, Sara G. Baer, Katherine Gross, Forest Isbell, Jennie R. Mclaren, Peter B. Reich, Katherine Suding, K. Blake Suttle, David Tilman, Zhuwen Xu, Qiang Yu

Biological Sciences Faculty Research and Publications

Understanding how global change drivers (GCDs) affect aboveground net primary production (ANPP) through time is essential to predicting the reliability and maintenance of ecosystem function and services in the future. While GCDs, such as drought, warming and elevated nutrients, are known to affect mean ANPP, less is known about how they affect inter-annual variability in ANPP. We examined 27 global change experiments located in 11 different herbaceous ecosystems that varied in both abiotic and biotic conditions, to investigate changes in the mean and temporal variability of ANPP (measured as the coefficient of variation) in response to different GCD manipulations, including …

Survivor Microbial Populations In Post-Chlorinated Wastewater Are Strongly Associated With Untreated Hospital Sewage And Include Ceftazidime And Meropenem Resistant Populations, Rachelle E. Beattie, Troy Skwor, Krassimira R. Hristova

Biological Sciences Faculty Research and Publications

Wastewater treatment plant (WWTP) effluent has been implicated in the spread of antibiotic resistant bacteria (ARB), including pathogens, as the WWTP environment contains multiple selective pressures that may increase mutation rates, pathogen survivability, and induce gene transfer between bacteria. In WWTPs receiving hospital sewage, this selective effect may be more pronounced due to increased concentrations of antibiotics, ARB, and clinical pathogens from hospital sewage. To determine the extent to which hospital sewage contributes to the microbial community of disinfected wastewater which is released into the environment, we used 16S rRNA sequencing of hospital sewage, WWTP influent, primary effluent, Post-Chlorinated Effluent, …

Freshwater Sediment Microbial Communities Are Not Resilient To Disturbance From Agricultural Land Runoff, Rachelle E. Beattie, Aditya Bandla, Sanjay Swarup, Krassimira R. Hristova

Biological Sciences Faculty Research and Publications

Microorganisms are critically important for the function of surface water ecosystems but are frequently subjected to anthropogenic disturbances at either acute (pulse) or long-term (press) scales. Response and recovery of microbial community composition and function following pulse disturbance is well-studied in controlled, laboratory scale experiments but is less well-understood in natural environments undergoing continual press disturbance. The objectives of this study were to determine the drivers of sediment microbial compositional and functional changes in freshwaters receiving continual press disturbance from agricultural land runoff and to evaluate the ability of the native microbial community to resist disturbance related changes as a …

Effects Of Low-Level Artificial Light At Night On Kentucky Bluegrass And Introduced Herbivore, Morgan Crump, Cassandra Brown, Robert J. Griffin-Nolan, Lisa Angeloni, Nathan P. Lemoine, Brett Seymoure

Biological Sciences Faculty Research and Publications

Increasing evidence suggests that artificial light at night (ALAN) can negatively impact organisms. However, most studies examine the impacts of ALAN on a single species or under high levels of artificial light that are infrequent or unrealistic in urban environments. We currently have little information on how low levels of artificial light emanating from urban skyglow affect plants and their interactions with herbivores. We examined how low levels of ALAN affect grass and insects, including growth rate, photosynthesis, and stomatal conductance in grass, and foraging behavior and survival in crickets. We compared growth and leaf-level gas exchange of Kentucky Bluegrass …

The Role Of System Xc- In Cognition: The Importance Of Neuron-Astrocyte Signaling, Evan Michael Hess

Dissertations (1934 -)

The biological basis of human intelligence is largely a mystery, but likely required evolutionary adaptations to achieve the information processing capacity needed to expand the complexity of cognition among species. The link between evolutionary expansion of signaling complexity in the brain and cognition has largely focused on neuronal mechanisms, in part because information processing has historically been attributed to these cells. However, astrocytes are emerging as a second type of brain cell that is capable of processing information due to their capacity to release glutamate and, thereby, regulate neural circuits. Hence, a modern question is whether astrocytes contributed to the …

Chronic Variable Stress Induces Avolition And Disrupts Corticoaccumbens Encoding Of Approach Cues, Mitchell Spring

Dissertations (1934 -)

Disorders in the ability to process, evaluate, and interact with rewards are hallmarks of a range of mental illnesses. Such disorders are multi-faceted and arise from altered activity throughout diffuse brain regions. Chronic variable stress (CVS) is an oft-used tool for modeling reward-related disorders in preclinical research because it impairs the function of multiple brain regions and causes a range of severe hedonic and motivational deficits. While much research has focused on the former, the latter is poorly characterized. A panel of behavioral tests was used to characterize the effect of CVS exposure on different facets of reward related behaviors …

Can Functional Traits Explain Plant Coexistence? A Case Study With Tropical Lianas And Trees, Felipe N. A. Mello, Sergio Estrada Villegas, David M. Defilippis, Stefan A. Schnitzer

Biological Sciences Faculty Research and Publications

Organisms are adapted to their environment through a suite of anatomical, morphological, and physiological traits. These functional traits are commonly thought to determine an organism’s tolerance to environmental conditions. However, the differences in functional traits among co-occurring species, and whether trait differences mediate competition and coexistence is still poorly understood. Here we review studies comparing functional traits in two co-occurring tropical woody plant guilds, lianas and trees, to understand whether competing plant guilds differ in functional traits and how these differences may help to explain tropical woody plant coexistence. We examined 36 separate studies that compared a total of 140 …

The Defining Genomic And Predicted Metabolic Features Of The Acetobacterium Genus, Daniel E. Ross, Christopher Marshall, Djuna Gulliver, Harold D. May, R. Sean Norman

Biological Sciences Faculty Research and Publications

Acetogens are anaerobic bacteria capable of fixing CO₂ or CO to produce acetyl coenzyme A (acetyl-CoA) and ultimately acetate using the Wood-Ljungdahl pathway (WLP). Acetobacterium woodii is the type strain of the Acetobacterium genus and has been critical for understanding the biochemistry and energy conservation in acetogens. Members of the Acetobacterium genus have been isolated from a variety of environments or have had genomes recovered from metagenome data, but no systematic investigation has been done on the unique and various metabolisms of the genus. To gain a better appreciation for the metabolic breadth of the genus, we sequenced the …

The Actin Cytoskeletal Network Plays A Role In Yeast Prion Transmission And Contributes To Prion Stability, Jane E. Dorweiler, Mitchell J. Oddo, Douglas R. Lyke, Jacob A. Reilly, Brett T. Wisniewski, Emily E. Davis, Abigail M. Kuborn, Stephen J. Merrill, Anita L. Manogaran

Biological Sciences Faculty Research and Publications

Chaperone networks are required for the shearing and generation of transmissible propagons from pre‐existing prion aggregates. However, other cellular networks needed for maintaining yeast prions are largely uncharacterized. Here, we establish a novel role for actin networks in prion maintenance. The [PIN ⁺] prion, also known as [RNQ ⁺], exists as stable variants dependent upon the chaperone machinery for the transmission of propagons to daughter cells during cell division and cytoplasmic transfer. Loss of the Hsp104 molecular chaperone leads to the growth of prion particles until they are too large to be transmitted. Here, we isolated …

The Negative Effect Of Lianas On Tree Growth Varies With Tree Species And Season, Alejandro Venegas-Gonzalez, Felipe N. A. Mello, Stefan A. Schnitzer, Ricardo G. Cesar, Mario Tomazello-Filho

Biological Sciences Faculty Research and Publications

Lianas reduce tree growth, reproduction, and survival in tropical forests. Liana competition can be particularly intense in isolated forest fragments, where liana densities are high, and thus, host tree infestation is common. Furthermore, lianas appear to grow particularly well during seasonal drought, when they may compete particularly intensely with trees. Few studies, however, have experimentally quantified the seasonal effects of liana competition on multiple tree species in tropical forests. We used a liana removal experiment in a forest fragment in southeastern Brazil to test whether the effects of lianas on tree growth vary with season and tree species identity. We …

Conserved Zz/Zw Sex Chromosomes In Caribbean Croaking Geckos (Aristelliger: Sphaerodactylidae), Shannon E. Keating, Aaron H. Griffing, Stuart V. Nielsen, Daniel P. Scantlebury, Tony Gamble

Biological Sciences Faculty Research and Publications

Current understanding of sex chromosome evolution is largely dependent on species with highly degenerated, heteromorphic sex chromosomes, but by studying species with recently evolved or morphologically indistinct sex chromosomes we can greatly increase our understanding of sex chromosome origins, degeneration and turnover. Here, we examine sex chromosome evolution and stability in the gecko genus Aristelliger. We used RADseq to identify sex‐specific markers and show that four Aristelliger species, spanning the phylogenetic breadth of the genus, share a conserved ZZ/ZW system syntenic with avian chromosome 2. These conserved sex chromosomes contrast with many other gecko sex chromosome systems by showing …

Bk Potassium Currents Contribute Differently To Action Potential Waveform And Firing Rate As Rat Hippocampal Neurons Mature In The First Postnatal Week, Michael Hunsberger, Michelle Mynlieff

Biological Sciences Faculty Research and Publications

The large-conductance calcium-activated potassium (BK) channel is a critical regulator of neuronal action potential firing and follows two distinct trends in early postnatal development: an increase in total expression and a shift from the faster activating STREX isoform to the slower ZERO isoform. We analyzed the functional consequences of developmental trends in BK channel expression in hippocampal neurons isolated from neonatal rats aged 1 to 7 days. Following overnight cultures, action potentials and currents were recorded using whole cell patch-clamp electrophysiology. These neurons undergo a steady increase in excitability during this time, and the effect of blockade of BK channel …

The Structure And Symmetry Of The Radial Spoke Protein Complex In Chlamydomonas Flagella, Emiliya Poghosyan, Ioan Iacovache, Lenka Faltova, Alexander Leitner, Pinfen Yang, Dennis R. Diener, Ruedi Aebersold, Benoit Zuber, Takashi Ishikawa

Biological Sciences Faculty Research and Publications

The radial spoke is a key element in a transducer apparatus controlling the motility of eukaryotic cilia. The transduction biomechanics is a long-standing question in cilia biology. The radial spoke has three regions – a spoke head, a bifurcated neck and a stalk. Although the neck and the stalk are asymmetric, twofold symmetry of the head has remained controversial. In this work we used single particle cryo-electron microscopy (cryo-EM) analysis to generate a 3D structure of the whole radial spoke at unprecedented resolution. We show the head region at 15 Å (1.5 nm) resolution and confirm twofold symmetry. Using distance …