Biology

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This collection includes scholarly output from both faculty and students in the Biology department.

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Drosophila klaroid encodes a SUN domain protein required for Klarsicht localization to the nuclear envelope and nuclear migration in the eye
(Taylor & Francis, 2007-04) Kracklauer, Martin P.; Banks, Susan M. L.; Xie, Xuanhua; Wu, Yaning; Fischer, Janice A.
KASH (Klarsicht/Anc-1/Syne homology) domain proteins are cytoskeleton-associated proteins localized uniquely to the outer nuclear membrane. Klarsicht is a KASH protein required for nuclear migration in differentiating cells of the Drosophila eye. The C-terminal KASH domain of Klarsicht resides in the perinuclear space, and the cytoplasmic moiety connects to the microtubule organizing center. In C. elegans and vertebrate cells, SUN (Sad1/UNC-84) domain proteins reside in the inner nuclear membrane and tether KASH proteins to the outer nuclear membrane. Is there a Drosophila SUN protein that performs a similar function, and if so, is it like Klarsicht, obviously essential for [...]
Auxilin is essential for Delta signaling
(Company Of Biologists Limited, 2008-03) Eun, Suk Ho; Banks, Susan M. L.; Fischer, Janice A.
Endocytosis regulates Notch signaling in both signaling and receiving cells. A puzzling observation is that endocytosis of transmembrane ligand by the signaling cells is required for Notch activation in adjacent receiving cells. A key to understanding why signaling depends on ligand endocytosis lies in identifying and understanding the functions of crucial endocytic proteins. One such protein is Epsin, an endocytic factor first identified in vertebrate cells. Here, we show in Drosophila that Auxilin, an endocytic factor that regulates Clathrin dynamics, is also essential for [...]
On deterministic and stochastic models of kleptoparasitism
(Taylor & Francis, 2009) Crowe, Mary L.; Fitzgerald, Meghan R.; Remington, D. L.; Rychtář, Jan
Kleptoparasitism, the stealing of food items, is a common biological phenomenon that has been studied mostly with the help of deterministic dynamics for infinite populations. The infinite population assumption takes the models far from the biological reality. In this paper we provide a review of the main theoretical works on kleptoparasitism and then focus on the stochastic dynamics of kleptoparasitic individuals in finite populations. We solve the dynamics analytically for populations of 2 and 3 individuals. With the help of numerical solution of the dynamics, we were able to conclude that the behavior of the uptake rate in the population is mostly determined by the uptake rates at populations of 2 and 3 individuals. If the individuals do better in a pair, then the uptake rate is a decreasing function of the population size. If the individuals do better in a triplet than in a pair, then the uptake rate is a zigzag function with lows for even population sizes and ups for uneven population sizes.
Game theoretic model of brood parasitism in a dung beetle Onthophagus taurus
(Springer Netherlands, 2009-08) Crowe, Mary L.; Fitzgerald, Meghan R.; Remington, D. L.; Ruxton, G. D.; Rychtář, Jan
We present a game theoretic model of brood parasitism in the dung beetle Onthophagus taurus. Female O. taurus engage in brood parasitism when they attack a brood ball made by another female, destroy the existing egg and place one of their own eggs to develop within the existing dung ball. Brood parasitism is more costly than other forms of kleptoparasitism because an individual loses the total investment in an offspring. In this paper, we outline the behaviors involved in brood ball production and provide time estimates of those behaviors. The model is then used to predict when it is beneficial to steal the brood ball created by another female and when it is beneficial for a female to create her own. We also investigate how long a female should guard her eggs.
Science and religion : understanding the issues / Nancy Morvillo.
(Wiley-Blackwell Publishing, 2010-03-18) Morvillo, Nancy
Review: "Addressing the complex issues at the interface of science and religion, this introductory textbook examines a range of basic scientific topics and their theological responses, including methodology, cosmology, evolution, and contemporary bio-ethical and environmental concerns. To shed light on the various issues at the crossroads of religion and science, the text also delves into the past to examine ideas from early scientists and theologians that have helped shape current thinking. While diverse viewpoints are considered, the focus of the text is on theological responses to science from a Christian perspective, and emphasizes areas where science and religion merge, rather than where they conflict." "Taking a balanced approach to the main debates, each chapter is accompanied by discussion questions and a list of biblical passages and relevant primary readings by a wide range of scientists and theologians. Timely, and without engaging in advocacy, Science and Religion: Understanding the Issues is an accessible introduction to the fascinating interface of science and theology."--BOOK JACKET.
The stochastic modelling of kleptoparasitism using a Markov process
(Elsevier, 2010-05) Broom, Mark; Crowe, Mary L.; Fitzgerald, Meghan R.; Rychtář, Jan
Kleptoparasitism, the stealing of food items from other animals, is a common behaviour observed across a huge variety of species, and has been subjected to significant modelling effort. Most such modelling has been deterministic, effectively assuming an infinite population, although recently some important stochastic models have been developed. In particular the model of Yates and Broom (Stochastic models of kleptoparasitism. J. Theor. Biol. 248 (2007), 480-489) introduced a stochastic version following the original model of Ruxton and Moody (The ideal free distribution with kleptoparasitism. J. Theor. Biol. 186 (1997), 449-458), and whilst they generated results of interest, they did not solve the model explicitly. In this paper, building on methods used already by van der Meer and Smallegange (A stochastic version of the Beddington-DeAngelis functional response: Modelling interference for a finite number of predators. J. Animal Ecol. 78 (2009) 134-142) we give an exact solution to the distribution of the population over the states for the Yates and Broom model and investigate the effects of some key biological parameters, especially for small populations where stochastic models can be expected to differ most from their deterministic equivalents.
The functions of auxilin and Rab11 in Drosophila suggest that the fundamental role of ligand endocytosis in notch signaling cells is not recycling
(Public Library of Science, 2011-03-23) Banks, Susan M. L.; Cho, Bomsoo; Eun, Eun; Lee, Ji-Hoon; Windler, Sarah L; Xie, Xuanhua; Bilder, David; Fischer, Janice A.
Notch signaling requires ligand internalization by the signal sending cells. Two endocytic proteins, epsin and auxilin, are essential for ligand internalization and signaling. Epsin promotes clathrin-coated vesicle formation, and auxilin uncoats clathrin from newly internalized vesicles. Two hypotheses have been advanced to explain the requirement for ligand endocytosis. [...]
Ecology of the Eastern Ribbonsnake (Thamnophis sauritus) in southern Alabama with evidence of seasonal multiple broods
(Herpetological Conservation and Biology, 2011-12) Langford, Gabriel J.; Borden, Joel A.; Nelson, David H.
Studies are lacking on the ecology of the Eastern Ribbonsnake (Thamnophis sauritus), especially in the southern United States. We describe some aspects of the sexual dimorphism, sex ratio, feeding habits, reproductive biology, and seasonal activity of the Eastern Ribbonsnake in a southern Alabama Tupelo-Gum swamp from 2003-2005. We captured 339 Eastern Ribbonsnakes 379 times; females were significantly longer than males, but males had longer tails. Snakes were active year-round, and the longest straight-line distance travelled by any snake was 1,050 m. Snakes consumed only frogs (Hyla spp. and Lithobates spp.); a shift occurred when juveniles switched from feeding on tadpoles to adult frogs. We found females had an extended reproductive season, producing broods April-October. Two females double brooded during the 2004 reproductive season, with 99 and 118 days between broods. The average brood size for Eastern Ribbonsnakes from six females that produced eight broods was 14 ± 3.18 (range 9-19). A reduction in brood size occurred in both females that produced multiple broods, but no decrease in neonate snout-vent length was detected between broods. Overall, our study provides needed natural history data from a southern location and the first evidence for multiple broods in a wild, temperate snake.
Population genomics of resource exploitation: insights from gene expression profiles of two Daphnia ecotypes fed alternate resources
(Blackwell Pub. Ltd, 2012-02) Dudycha, Jeffry L.; Brandon, Christopher S.; Deitz, Kevin C.
Consumer-resource interactions are a central issue in evolutionary and community ecology because they play important roles in selection and population regulation. Most consumers encounter resource variation at multiple scales, and respond through phenotypic plasticity in the short term or evolutionary divergence in the long term. The key traits for these responses may influence resource acquisition, assimilation, and/or allocation. To identify relevant candidate genes, we experimentally assayed genome-wide gene expression in pond and lake Daphnia ecotypes exposed to alternate resource environments. [...]
Evidence for the Southward Migration of Mud Banks in Florida Bay
(Elsevier, 2012-05-15) Taylor, Kristian H.; Purkis, Samuel J.
The latticework of shallow polygonal mud banks encircling deeper ponds is a key morphological characteristic of Florida Bay. Composed of lime mud produced largely by calcareous algae and epibionts, these banks limit water exchange between the interior Bay and ocean waters from both the Gulf of Mexico and the Atlantic. They also influence salinity and benthic habitat distribution. It has been proposed that the position of mud banks may be dynamic, migrating southwards with time, but no long-term study has examined the spatial arrangement of banks within Florida Bay over sufficiently long timescales to ascertain movement. Using time-separated bathymetry surveys and aerial photography datasets spanning a period of many decades, this study establishes that indeed the bank positions are temporally dynamic. The work was conducted using geographic information systems (GIS), with all data referenced to the position of relatively stable islands. The analysis reveals a southward migration trend (headings ranging from 280[degrees] to 240[degrees]) with rates averaging 1.27m/year. For the first time in Florida Bay, the migration and vector of movement for mud banks have been documented. Despite the southward movement, mud bank morphology remained consistent. It is speculated that strong winter winds out of the north/northeast provide the mechanism for such migration.
Proving the "proof": Interdisciplinary undergraduate research positively impacts students
(Springer, 2012-11-03) Crowe, Mary L.; Rychtář, Jan; Rueppell, O.; Chhetri, M.; Remington, D. L.
The math biology program at UNCG has been running since 2006 when we first received the funding from NSF. Every year, we provided integrated research projects at the interface of biology and mathematics to eight UNCG undergraduate students who worked in interdisciplinary teams. Up to date, our project resulted in 32 peer-reviewed publications and over 200 presentations; this demonstrates the extent to which undergraduate research can produce genuine scientific advancement. Moreover, our program also prepared UNCG students for rigorous interdisciplinary graduate studies and career opportunities and set them on a path toward productive careers as twenty-one century scientists and educators. We hope our experience will motivate and encourage others to pursue similar efforts.
A field test of optional unrelated question randomized response models: Estimates of risky sexual behaviors
(Springer, 2012-11-03) Gill, Tracy Spears; Tuck, Anna; Gupta, Sat; Crowe, Mary L.; Figueroa, Jennifer
Recently Gupta et al. (Involve J Math, 2013) introduced optional unrelated question randomized response models for both the binary response and quantitative response to sensitive survey questions. Asymptotic normality was established for the mean estimator of the sensitive variable and for the prevalence estimator of the sensitive characteristic. Asymptotic normality was also established for the sensitivity level estimator in each case using first order approximation. These mathematical results were validated using computer simulations. In this paper, the binary and quantitative response models are utilized in surveys of sensitive behaviors to verify that these results hold true in fieldwork applications. The two sensitive questions of interest in the survey are "Have you ever been told by a healthcare professional that you have a sexually transmitted disease?" and "How many sexual partners have you had in the last 12 months?" The target population was undergraduate students enrolled at UNC Greensboro during the 2012-2013 academic year. Subjects were asked these questions by optional unrelated question RRT, check-box survey method, and by direct face-to-face interview. The results of these three methods are compared to each other, as well as to existing published information on these two sensitive behaviors. Estimates provided by the optional unrelated question randomized response models are in line with the mathematical results in Gupta et al. (Involve J Math, 2013). This study also provides the first estimate of sensitivity level through a fieldwork survey.
Transmission, host specificity, and seasonal occurrence of cyrtosomum penneri (nematoda: Atractidae) in lizards from Florida
(Allen Press, 2013) Langford, Gabriel J.; Willobee, Brent A.; Isidoro, Luiz F.
Experimental infections and field-collected lizards were used to investigate issues of transmission, host specificity, and seasonal occurrence in the nematode Cyrtosomum penneri (Cosmocercoidea: Atractidae). Anolis sagrei (87 males, 42 females) were captured from the Florida Southern College campus, Polk County, Florida, from October 2010 to September 2011, and 8,803 C. penneri were collected from their intestines. During the breeding season all sexually mature (SVL ≥34 mm) A. sagrei were infected, whereas juvenile lizards.
Co-Occurrence of Haematoloechus complexus and Rhabdias joaquinensis in the Plains Leopard Frog from Nebraska
(Allen Press, 2013) Langford, Gabriel J.; Vhora, M. Suhail; Bolek, Matthew G.; Janovy, John Jr.
Species of Haematoloechus and Rhabdias both are ubiquitous lung parasites of frogs, yet surprisingly little research has been conducted on the interactions between these worms. In a small Nebraska stream, 256 Rhabdias joaquinensis and 225 Haematoloechus complexus were found in the lungs of Lithobates (=Rana) blairi. Thirty-six of the 44 (82%) frogs were co-infected with H. complexus and R. joaquinensis whereas 5 (11%) frogs were infected with only 1 species and 3 (7%) frogs were uninfected. Tests for association between H. complexus and R. joaquinensis found a significant positive relationship between the 2 parasites. Significant positive relationships in intensity of infection were found when both lungs were combined but not when lungs were considered individually. Tests for association between H. complexus and R. joaquinensis found no relationship between the worms in the anterior and posterior portions of the lungs. These data suggest that H. complexus and R. joaquinensis do not competitively exclude each other from the lungs of L. blairi in southeastern Nebraska.
Effect of density and extra dung on brood parasitism in the dung beetle, Onthophagus Taurus
(Springer US, 2013-03) Crowe, Mary L.; Raspet, Erin; Rychtář, Jan; Gupta, Sat
Kleptoparasitism has not been well documented in insects and intraspecific brood parasitism is even less well known. This study examines the effect of extra resources and density on the probability of kleptoparasitism in the bull headed dung beetle Onthophagus taurus. A high level (>60 %) of kleptoparasitism was found across all treatments and suggest that although density may not affect the probability to kleptoparasitize, it may influence brood ball production. This study also documents for the first time that male O. taurus kleptoparasitize.
Ecological constraints on sensory systems: compound eye size in Daphnia is reduced by resource limitation
(Springer, 2014-08) Brandon, Christopher S.; Dudycha, Jeffry L.
Eye size is an indicator of visual capability, and macroevolutionary patterns reveal that taxa inhabiting dim environments have larger eyes than taxa from bright environments. This suggests that the light environment is a key driver of variation in eye size. Yet other factors not directly linked with visual tasks (i.e., non-sensory factors) may influence eye size. We sought to jointly investigate the roles of sensory (light) and non-sensory factors (food) in determining eye size and ask whether non-sensory factors could constrain visual capabilities. We tested environmental influences on eye size in four species of the freshwater crustacean Daphnia, crossing bright and dim light levels with high and low resource levels. We measured absolute eye size and eye size relative to body size in early and late adulthood. In general, Daphnia reared on low resources had smaller eyes, both absolutely and relatively. In contrast to the dominant macroevolutionary pattern, phenotypic plasticity in response to light was rarely significant. These patterns of phenotypic plasticity were true for overall diameter of the eye and the diameter of individual facets. We conclude that non-sensory environmental factors can influence sensory systems, and in particular, that resource availability may be an important constraint on visual capability.
Acute increase of α-synuclein inhibits synaptic vesicle recycling evoked during intense stimulation
(Molecular Biology of the Cell (MBoC), 2014-10) Busch, David J.; Oliphint, Paul A.; Walsh, Rylie B.; Banks, Susan M. L.; Woods, Wendy S.; George, Julia M.; Morgan, Jennifer R.
Parkinson's disease is associated with multiplication of the α-synuclein gene and abnormal accumulation of the protein. In animal models, α-synuclein overexpression broadly impairs synaptic vesicle trafficking. However, the exact steps of the vesicle trafficking pathway affected by excess α-synuclein and the underlying molecular mechanisms remain unknown. Therefore we acutely increased synuclein levels at a vertebrate synapse and performed a detailed ultrastructural analysis of the effects on presynaptic membranes. At stimulated synapses (20 Hz), excess synuclein caused a loss of synaptic vesicles and an expansion of the plasma membrane, indicating an impairment of vesicle recycling. The N-terminal domain (NTD) of synuclein, which folds into an α-helix, was sufficient to reproduce these effects. In contrast, α-synuclein mutants with a disrupted N-terminal α-helix (T6K and A30P) had little effect under identical conditions. Further supporting this model, another α-synuclein mutant (A53T) with a properly folded NTD phenocopied the synaptic vesicle recycling defects observed with wild type. Interestingly, the vesicle recycling defects were not observed when the stimulation frequency was reduced (5 Hz). Thus excess α-synuclein impairs synaptic vesicle recycling evoked during intense stimulation via a mechanism that requires a properly folded N-terminal α-helix.
Elucidating the life history and ecological aspects of Allodero hylae (Annelida: Clitellata: Naididae), a parasitic oligochaete of invasive Cuban tree frogs in Florida
(Allen Press, 2015) Andrews, Jessee M.; Childress, Jasmine N.; Iakovidis, Triantafilos J.; Langford, Gabriel J.
Given their ubiquitous nature, it is surprising that more oligochaete annelid worms (Annelida: Clitellata) have not adopted an endoparasitic lifestyle. Exceptions, however, are the understudied members of the genus Dero (Allodero) that parasitize the ureters of tree frogs and toads. This study experimentally explores the life cycle and host specificity of Allodero hylae, the worm's use of chemical cues in host searching, and its seasonal prevalence and abundance over a year-long collection period on the Florida Southern College campus. A total of 2,005 A. hylae was collected from the ureter, urinary bladder, or expressed urine of wild Osteopilus septentrionalis; a significant positive correlation was found between host snout–vent length and parasite intensity for female but not male hosts. Monthly prevalence of A. hylae reached a peak of 58% in April, but never dropped below 20% in any month; mean abundance peaked March–May, whereas few worms were recovered in December and January. Confirming a parasitic lifestyle, wild-collected hosts with intense infections, typically >40 worms, showed obvious dilatation of the ureter wall, and some young-of-the-year O. septentrionalis exposed to A. hylae in the laboratory were killed by the apparent rupture of the host's ureter. The worm has a direct life cycle: worms expelled in the host's urine are capable of locating and re-infecting other hosts within aquatic microhabitats such as bromeliad tanks, and worms can survive for weeks in a free-living environment, even undergoing a morphological change. Further, chemotaxis assays found a positive response to a tree frog attractant for worms recently removed from hosts. Overall, this study provides the first multifaceted investigation on the life history and ecology of any Allodero spp., which offers new insights into an understudied endoparasitic oligochaete.
Selection on incremental variation of eye size in a wild population of Daphnia
(Blackwell Science, 2015-11) Brandon, Christopher S.; James, T.; Dudycha, Jeffry L.
Several studies of eye morphology have analysed macroevolutionary patterns in the diversity of eyes, and although these studies are often linked to environment or behaviour, they provide only indirect evidence of selection. Specific data to show the microevolutionary potential for adaptation by natural selection in eye morphology have been lacking. We document directional selection on eye size, an important determinant of visual capabilities, in a wild population of the freshwater microcrustacean Daphnia. We show that [...] (© 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.)
Ecological factors responsible for the geographic distribution of Rhabdias joaquinensis: where do lungworms infect anurans in nature?
(Allen Press, 2016-03) Langford, Gabriel J.; Janovy, John Jr.
The lungworm Rhabdias joaquinensis (Nematoda: Rhabdiasidae) is a common parasite of anurans in eastern Nebraska, yet absent from the same hosts in western Nebraska. This study investigated the ecology of the lungworm’s free-living stages that reside in host feces and surrounding soils to establish the worm’s free-living niche in eastern Nebraska. Using a comparative method, this study also investigated the absence of lungworms in western Nebraska’s Sandhills. Soil composition, moisture, and temperature were experimentally varied in the laboratory to assess their effects on juvenile development and survival. Field mesocosm and host defecation experiments were used to determine where in nature lungworms survive and eventually infect frogs and toads and to discover if vegetation facilitates lungworm transmission to hosts. The results found loam soils were amenable to lungworm development, whereas soils with high clay or sand content produced few infective lungworms. Soil moisture <50 % did not support lungworm development. Infective juveniles successfully developed between 5 and 35 °C, albeit at different rates, whereas only a limited number of non-infective worms developed at 40 °C. Field studies found that shoreline environments supported lungworm development, and the majority of lungworm infections appear to occur within a zone of infection adjacent to shorelines in eastern Nebraska. The prevalence in vegetation mesocosms was 100 %, and a significantly higher mean abundance was found in toads from containers with vegetation than without. Overall, these experiments suggest that the spatial distribution of R. joaquinensis in Nebraska is constrained by the worm’s ability to survive and reproduce in a soil matrix.

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