Biology Commons^™

Gabaergic Synaptic Scaling Is Triggered By Changes In Spiking Activity Rather Than Transmitter Receptor Activation, Carlos Gonzalez-Islas, Zahraa Sabra, Ming-Fai Fong, Pernille Bülow, Nicholas Au Yong, Kathrin Engisch, Peter Wenner

Biological Sciences Faculty Publications

Homeostatic plasticity represents a set of mechanisms that are thought to recover some aspect of neural function. One such mechanism called AMPAergic scaling was thought to be a likely candidate to homeostatically control spiking activity. However, recent findings have forced us to reconsider this idea as several studies suggest AMPAergic scaling is not directly triggered by changes in spiking. Moreover, studies examining homeostatic perturbations in vivo have suggested that GABAergic synapses may be more critical in terms of spiking homeostasis. Here we show results that GABAergic scaling can act to homeostatically control spiking levels. We find that increased or decreased …

Size Regulation Within The Germline Of The Developing Egg Chamber, Zoe Gladd Herdman

Undergraduate Honors Thesis Collection

The relationship between the size of a cell and the size of its intracellular structures must be precisely regulated for proper development and functioning of the mature organism; however, the mechanisms that establish and maintain this relationship are not known. Much of the work on organelle size scaling has focused on individual cells or organelles, with some looking at how size scaling is maintained during development. However, it is not known whether the size of multiple organelles is coordinately regulated, and how cell size and organelle size are regulated within a syncytium or group of connected cells. Because many cell …

Ecological Correlates Of Alligator Snapping Turtle Bite Performance, Ashley Herrin Gagnon

MSU Graduate Theses

The Alligator Snapping Turtle (Macrochelys temminckii) is one of many turtle species facing conservation challenges. Nearly extirpated in the 1980s, it is currently the subject of a head-start initiative, of which, any lasting behavioral or physiological effects were—until now—unknown! To evaluate the ability of captive-reared individuals to excel in natural habitats, and to foresee any future research or conservation challenges regarding this animal, I explored a suite of variables that influence bite performance and behaviors including captive or free-ranging status, and environmental conditions including body temperature and season. My results indicated that free-ranging M. temminckii outperform those residing …

The Allometry Of Daily Energy Expenditure In Hummingbirds: An Energy Budget Approach, Anushu Shankar, Donald R. Powers, Liliana M. Dávalos, Catherine H. Graham

Faculty Publications - Department of Biological & Molecular Science

1. Within-clade allometric relationships represent standard laws of scaling between energy and size, and their outliers provide new avenues for physiological and ecological research. According to the metabolic-level boundaries hypothesis, metabolic rates as a function of mass are expected to scale closer to 0.67 when driven by surface-related processes (e.g. heat or water flux), while volume-related processes (e.g. activity) generate slopes closer to one.

2. In birds, daily energy expenditure (DEE) scales with body mass (M) in the relationship log (DEE)=2.35+0.68×log (M), consistent with surface-level processes driving the relationship. However, taxon-specific patterns differ from the scaling slope of all birds. …

Integrating Morphology And Kinematics In The Scaling Of Hummingbird Hovering Metabolic Rate And Efficiency, Derrick J. E. Groom, M. Cecilia B. Toledo, Donald R. Powers, Bret W. Tobalske, Kenneth C. Welch Jr.

Faculty Publications - Department of Biological & Molecular Science

Wing kinematics and morphology are influential upon the aerodynamics of flight. However, there is a lack of studies linking these variables to metabolic costs, particularly in the context of morphological adaptation to body size. Furthermore, the conversion efficiency from chemical energy into movement by the muscles (mechanochemical efficiency) scales with mass in terrestrial quadrupeds, but this scaling relationship has not been demonstrated within flying vertebrates. Positive scaling of efficiency with body size may reduce the metabolic costs of flight for relatively larger species. Here, we assembled a dataset of morphological, kinematic, and metabolic data on hovering hummingbirds to explore the …

The Interaction Of Scale And Temperature In Elastically Powered Movements, Jeffrey P. Olberding

USF Tampa Graduate Theses and Dissertations

For many animals, rapid movements place high power demands on underlying muscles. Storage of muscle energy in elastic structures and the subsequent rapid release of that energy can effectively amplify muscle power. Elastic recoil can also confer thermal robustness to performance in behaviors occurring at variable temperatures. Muscle contractile performance tends to decrease at lower temperatures, but elastic recoil is less affected by temperature. Here I examine the impacts of temperature and scale in systems using elastic recoil and I explore possible interactive effects on movement performance.

I explored the role that muscle contractile properties play in the differences in …

Flight Mechanics And Control Of Escape Manoeuvres In Hummingbirds. Ii. Aerodynamic Force Production, Flight Control And Performance Limitations, Bo Cheng, Bret W. Tobalske, Donald R. Powers, Tyson L. Hedrick, Yi Wang, Susan M. Wethington, George T.C. Chiu, Xinyan Deng

Faculty Publications - Department of Biological & Molecular Science

The superior manoeuvrability of hummingbirds emerges from complex interactions of specialized neural and physiological processes with the unique flight dynamics of flapping wings. Escape manoeuvring is an ecologically relevant, natural behaviour of hummingbirds, from which we can gain understanding into the functional limits of vertebrate locomotor capacity. Here, we extend our kinematic analysis of escape manoeuvres from a companion paper to assess two potential limiting factors of the manoeuvring performance of hummingbirds: (1) muscle mechanical power output and (2) delays in the neural sensing and control system. We focused on the magnificent hummingbird (Eugenes fulgens, 7.8 g) and the black-chinned …

Performance And Scaling Of A Novel Locomotor Structure: Adhesive Capacity Of Climbing Gobiid Fishes, Richard W. Blob, Takashi Maie, Heiko L. Schoenfuss

R. W. Blob

Many species of gobiid fishes adhere to surfaces using a sucker formed from fusion of the pelvic fins. Juveniles of many amphidromous species use this pelvic sucker to scale waterfalls during migrations to upstream habitats after an oceanic larval phase. However, adults may still use suckers to re-scale waterfalls if displaced. If attachment force is proportional to sucker area and if growth of the sucker is isometric, then increases in the forces that climbing fish must resist might outpace adhesive capacity, causing climbing performance to decline through ontogeny. To test for such trends, we measured pressure differentials and adhesive suction …

Wrinkling In Buckling And A Thin Sheet, Narayanan Menon

Patterns Around Us

Module 1: Euler Buckling

Learning Objectives:

• What is an instability? A sudden change in behaviour in response to a small change in conditions.

• Instabilities usually involve a change in symmetry from a more symmetric situation to a less symmetric one

• The mechanism for an instability usually involves two competing forces (one force stabilizing the symmetric state, and the other one destabilizing it), with one suddenly winning the contest

• These competing forces in thin objects are often the forces of compression (destabilizing force - favors buckling or wrinkling) and of bending (stabilizing force).

Understanding by data collapse, the power of using …

The Effects Of Scaling On Bite Force And Suction Index In The Eastern Hellbender (Cryptobranchus Alleganiensis), Nicholas Patrick Larghi

USF Tampa Graduate Theses and Dissertations

The hellbender (Cryptobranchus alleganiensis) is a salamander that grows over a large range of body sizes (2-74 cm total length) making it an ideal organism for examining the effects of body size on morphology and performance. The goal of this study is to investigate the morphology changes over ontogeny and change in

feeding ability. Cryptobranchus feeds on small aquatic insects as juveniles and shifts to crayfish as they get larger. Morphology can be expected to change as an organism grows larger, and because morphology and performance are closely linked, this morphological change can result in a change in …

Performance And Scaling Of A Novel Locomotor Structure: Adhesive Capacity Of Climbing Gobiid Fishes, Richard W. Blob, Takashi Maie, Heiko L. Schoenfuss

Publications

Many species of gobiid fishes adhere to surfaces using a sucker formed from fusion of the pelvic fins. Juveniles of many amphidromous species use this pelvic sucker to scale waterfalls during migrations to upstream habitats after an oceanic larval phase. However, adults may still use suckers to re-scale waterfalls if displaced. If attachment force is proportional to sucker area and if growth of the sucker is isometric, then increases in the forces that climbing fish must resist might outpace adhesive capacity, causing climbing performance to decline through ontogeny. To test for such trends, we measured pressure differentials and adhesive suction …

Scaling Of Feeding Performance In Panther Grouper, Cromileptes Altivelis, Candace R. Read

Mahurin Honors College Capstone Experience/Thesis Projects

Fishes demonstrate the greatest change throughout ontogeny in body size of all vertebrates, some becoming twelve times their original length. Panther groupers, Cromileptes altivelis, are no exception. This vast size change influences other aspects of their lives including their feeding behavior, the prey they consume, and the capabilities of the mechanisms they use to capture prey. The change in the feeding performance of the panther grouper, Cromileptes altivelis, was quantified through buccal pressure recordings and high-speed videography. From this data, we can deduce that the larger juvenile was able to generate greater negative pressure within the mouth. It appears that …

Energetic Basis Of Colonial Living In Social Insects, Chen Hou, Michael Kaspari, Hannah B. Vander Zanden, James F. Gillooly

Biological Sciences Faculty Research & Creative Works

Understanding the ecology and evolution of insect societies requires greater knowledge of how sociality affects the performance of whole colonies. Metabolic scaling theory, based largely on the body mass scaling of metabolic rate, has successfully predicted many aspects of the physiology and life history of individual (or unitary) organisms. Here we show, using a diverse set of social insect species, that this same theory predicts the size dependence of basic features of the physiology (i.e., metabolic rate, reproductive allocation) and life history (i.e., survival, growth, and reproduction) of whole colonies. The similarity in the size dependence of these features in …

Integrating Spatial And Temporal Approaches To Understanding Species Richness, Ethan P. White, S. K. Morgan Ernest, Peter B. Adler, Allen H. Hurlbert, S. Kathleen Lyons

School of Biological Sciences: Faculty Publications

Understanding species richness patterns represents one of the most fundamental problems in ecology. Most research in this area has focused on spatial gradients of species richness, with a smaller area of emphasis dedicated to understanding the temporal dynamics of richness. However, few attempts have been made to understand the linkages between the spatial and temporal patterns related to richness. Here, we argue that spatial and temporal richness patterns and the processes that drive them are inherently linked, and that our understanding of richness will be substantially improved by considering them simultaneously. The species–time–area relationship provides a case in point: successful …

Revisiting A Model Of Ontogenetic Growth: Estimating Model Parameters From Theory And Data, Melanie E. Moses, Chen Hou, William H. Woodruff, Geoffrey B. West, Jeffery C. Nekola, Wenyun Zuo, James H. Brown

Biological Sciences Faculty Research & Creative Works

The ontogenetic growth model (OGM) of West et al. provides a general description of how metabolic energy is allocated between production of new biomass and maintenance of existing biomass during ontogeny. Here, we reexamine the OGM, make some minor modifications and corrections, and further evaluate its ability to account for empirical variation on rates of metabolism and biomass in vertebrates both during ontogeny and across species of varying adult body size. We show that the updated version of the model is internally consistent and is consistent with other predictions of metabolic scaling theory and empirical data. The OGM predicts not …

Genome Size Scaling Through Phenotype Space, Charles A. Knight, Jeremy M. Beaulieu

Biological Sciences

Background and Aims Early observations that genome size was positively correlated with cell size formed the basis of hypothesized consequences of genome size variation at higher phenotypic scales. This scaling was supported by several studies showing a positive relationship between genome size and seed mass, and various metrics of growth and leaf morphology. However, many of these studies were undertaken with limited species sets, and often performed within a single genus. Here we seek to generalize the relationship between genome size and the phenotype by examining eight phenotypic traits using large cross-species comparisons involving diverse assemblages of angiosperm and gymnosperm …

The Long And Winding Road: Influences Of Intracellular Metabolite Diffusion On Cellular Organization And Metabolism In Skeletal Muscle, Stephen T. Kinsey, Kristin M. Hardy, Bruce R. Locke

Biological Sciences

A fundamental principle of physiology is that cells are small in order to minimize diffusion distances for O₂ and intracellular metabolites. In skeletal muscle, it has long been recognized that aerobic fibers that are used for steady state locomotion tend to be smaller than anaerobic fibers that are used for burst movements. This tendency reflects the interaction between diffusion distances and aerobic ATP turnover rates, since maximal intracellular diffusion distances are ultimately limited by fiber size. The effect of diffusion distance on O₂ flux in muscle has been the subject of quantitative analyses for a century, but the …

A Reaction–Diffusion Analysis Of Energetics In Large Muscle Fibers Secondarily Evolved For Aerobic Locomotor Function, Kristin M. Hardy, Bruce R. Locke, Marilia Da Silva, Stephen T. Kinsey

Biological Sciences

The muscles that power swimming in the blue crab, Callinectes sapidus, grow hypertrophically, such that in juvenile crabs the cell diameters are

Does Intracellular Metabolite Diffusion Limit Post-Contractile Recovery In Burst Locomotor Muscle?, Stephen T. Kinsey, Pragyansri Pathi, Kristin M. Hardy, Amanda Jordan, Bruce R. Locke

Biological Sciences

Post-metamorphic growth in the blue crab entails an increase in body mass that spans several orders of magnitude. The muscles that power burst swimming in these animals grow hypertrophically, such that small crabs have fiber diameters that are typical of most cells (600μm). Thus, as the animals grow, their muscle fibers cross and greatly exceed the surface area to volume ratio (SA:V) and intracellular diffusion distance threshold that is adhered to by most cells. Large fiber size should not impact burst contractile function, but post-contractile recovery may be limited by low SA:V and excessive intracellular diffusion distances. A number of …