Integrative Biology Commons^™

The Contribution Of Marine Aggregate-Associated Bacteria To The Accumulation Of Pathogenic Bacteria In Oysters: An Agent-Based Model, Andrew M. Kramer, J. Evan Ward, Fred C. Dobbs, Melissa L. Pierce, John M. Drake

Integrative Biology Faculty and Staff Publications

Bivalves process large volumes of water, leading to their accumulation of bacteria, including potential human pathogens (e.g., vibrios). These bacteria are captured at low efficiencies when freely suspended in the water column, but they also attach to marine aggregates, which are captured with near 100% efficiency. For this reason, and because they are often enriched with heterotrophic bacteria, marine aggregates have been hypothesized to function as important transporters of bacteria into bivalves. The relative contribution of aggregates and unattached bacteria to the accumulation of these cells, however, is unknown. We developed an agent-based model to simulate accumulation of vibrio-type bacteria …

Adaptive Plasticity And Epigenetic Variation In Response To Warming In An Alpine Plant, Adrienne B. Nicotra, Deborah L. Segal, Gemma L. Hoyle, Aaron W. Schrey, Koen J. Verhoeven, Christina L. Richards

Integrative Biology Faculty and Staff Publications

Environmentally induced phenotypic plasticity may be a critical component of response to changing environments. We examined local differentiation and adaptive phenotypic plasticity in response to elevated temperature in half-sib lines collected across an elevation gradient for the alpine herb, Wahlenbergia ceracea. Using Amplified Fragment Length Polymorphism (AFLP), we found low but significant genetic differentiation between low- and high-elevation seedlings, and seedlings originating from low elevations grew faster and showed stronger temperature responses (more plasticity) than those from medium and high elevations. Furthermore, plasticity was more often adaptive for plants of low-elevation origin and maladaptive for plants of high elevation. With …

Ebola Cases And Health System Demand In Liberia, John M. Drake, Rajreni B. Kaul, Laura W. Alexander, Suzanne M. O’Regan, Andrew M. Kramer, J. Tomlin Pulliam, Matthew J. Ferrari, Andrew W. Park

Integrative Biology Faculty and Staff Publications

In 2014, a major epidemic of human Ebola virus disease emerged in West Africa, where human-to-human transmission has now been sustained for greater than 12 months. In the summer of 2014, there was great uncertainty about the answers to several key policy questions concerning the path to containment. What is the relative importance of nosocomial transmission compared with community-acquired infection? How much must hospital capacity increase to provide care for the anticipated patient burden? To which interventions will Ebola transmission be most responsive? What must be done to achieve containment? In recent years, epidemic models have been used to guide …

Immigration Can Destabilize Tri-Trophic Interactions: Implications For Conservation Of Top Predators, Kevin L. S. Drury, Jesse D. Suter, Jacob B. Rendall, Andrew M. Kramer, John M. Drake

Integrative Biology Faculty and Staff Publications

Top predators often have large home ranges and thus are especially vulnerable to habitat loss and fragmentation. Increasing connectance among habitat patches is therefore a common conservation strategy, based in part on models showing that increased migration between subpopulations can reduce vulnerability arising from population isolation. Although three-dimensional models are appropriate for exploring consequences to top predators, the effects of immigration on tri-trophic interactions have rarely been considered. To explore the effects of immigration on the equilibrium abundances of top predators, we studied the effects of immigration in the three-dimensional Rosenzweig-MacArthur model. To investigate the stability of the top predator …

Ebola Cases And Health System Demand In Liberia, John M. Drake, Rajreni B. Kaul, Laura W. Alexander, Suzanne M. O’Regan, Andrew M. Kramer, J. Tomlin Pulliam, Matthew J. Ferrari, Andrew W. Park

Integrative Biology Faculty and Staff Publications

In 2014, a major epidemic of human Ebola virus disease emerged in West Africa, where human-to-human transmission has now been sustained for greater than 12 months. In the summer of 2014, there was great uncertainty about the answers to several key policy questions concerning the path to containment. What is the relative importance of nosocomial transmission compared with community-acquired infection? How much must hospital capacity increase to provide care for the anticipated patient burden? To which interventions will Ebola transmission be most responsive? What must be done to achieve containment? In recent years, epidemic models have been used to guide …

Nitrogen Inputs And Losses In Response To Chronic Co2 Exposure In A Subtropical Oak Woodland, B. A. Hungate, B. D. Duval, P. Dijkstra, D. W. Johnson, M. E. Ketterer, Peter Stiling, W. Cheng, J. Millman, A. Hartley, D. B. Stover

Integrative Biology Faculty and Staff Publications

Rising atmospheric CO₂ concentrations may alter the nitrogen (N) content of ecosystems by changing N inputs and N losses, but responses vary in field experiments, possibly because multiple mechanisms are at play. We measured N fixation and N losses in a subtropical oak woodland exposed to 11 years of elevated atmospheric CO₂ concentrations. We also explored the role of herbivory, carbon limitation, and competition for light or nutrients in shaping the response of N fixation to elevated CO₂. Elevated CO₂ did not significantly alter gaseous N losses, but lower recovery and deeper distribution in the …

Assessing The In Situ Fertilization Status Of Two Marine Copepod Species, Temora Longicornis And Eurytemora Herdmani; How Common Are Unfertilized Eggs In Nature?, Rachel S. Lasley-Rasher, Andrew M. Kramer, Victoria Burdett-Coutts, Jeannette Yen

Integrative Biology Faculty and Staff Publications

We utilized an egg staining technique to measure the in situ fertilization success of two marine copepod species, Temora longicornis and Eurytemora herdmani from May to October 2008 in coastal Maine and correlated fertilization success with environmental conditions in their habitat. T. longicornis is a free spawning species that releases eggs into the ambient seawater after mating. In contrast, E. herdmani carries eggs in an egg sac until they hatch. The proportion of fertilized eggs within E. herdmani egg sacs was significantly higher than the freely spawned clutches of T. longicornis. This may be a result of the asymmetrical costs …

Time To Competitive Exclusion, Andrew M. Kramer, John M. Drake

Integrative Biology Faculty and Staff Publications

A predictive theory of population extinction for natural populations requires integrating the effects of stochasticity with the interactions engaged in with populations of other species. The theory of competitive exclusion predicts that inferior competitors for a limiting resource will be driven to extinction, but the effects of resource competition on time to extinction have not been examined. We studied a stochastic version of Tilman's resource competition model to examine two species competition-driven extinction. Simulations showed that competitive imbalance, population size and demographic rates of the “inferior” competitor were the most important determinants of mean extinction time, while factors including resource …

Blood-Brain Barrier Alterations Provide Evidence Of Subacute Diaschisis In An Ischemic Stroke Rat Model, Svitlana Garbuzova-Davis, Maria C. O. Rodrigues, Diana G. Hernandez-Ontiveros, Naoki Tajiri, Aric Frisna-Deyo, Sean M. Boffeli, Jerry V. Abraham, Mibel Pabon, Andrew Wagner, Hiroto Ishikawa, Kazutaka Shinozuka, Edward M. Haller, Paul Sanberg, Yuji Kaneko, Cesario Borlongan

Integrative Biology Faculty and Staff Publications

Background: Comprehensive stroke studies reveal diaschisis, a loss of function due to pathological deficits in brain areas remote from initial ischemic lesion. However, blood-brain barrier (BBB) competence in subacute diaschisis is uncertain. The present study investigated subacute diaschisis in a focal ischemic stroke rat model. Specific focuses were BBB integrity and related pathogenic processes in contralateral brain areas.

Methodology/Principal Findings: In ipsilateral hemisphere 7 days after transient middle cerebral artery occlusion (tMCAO), significant BBB alterations characterized by large Evans Blue (EB) parenchymal extravasation, autophagosome accumulation, increased reactive astrocytes and activated microglia, demyelinization, and neuronal damage were detected in the striatum, …

Iron Modulates Cell Survival In A Ras- And Mapk-Dependent Manner In Ovarian Cells, K. A. Bauckman, Edward M. Haller, I. Flores, M. Nanjundan

Integrative Biology Faculty and Staff Publications

Ovarian cancer is a leading cause of cancer death in women in the United States. While the majority of ovarian cancers are serous, some rarer subtypes (i.e. clear cell) are often associated with endometriosis, a benign gynecological disease. Iron is rich in the cyst fluid of endometriosis-associated ovarian cancers and induces persistent oxidative stress. The role of iron, an essential nutrient involved in multiple cellular functions, in normal ovarian cell survival and ovarian cancer remains unclear. Iron, presented as ferric ammonium citrate (FAC), dramatically inhibits cell survival in ovarian cancer cell types associated with Ras mutations, while it is without …

Bacterial Colonization And Extinction On Marine Aggregates: Stochastic Model Of Species Presence And Abundance, Andrew M. Kramer, M. Maille Lyons, Fred C. Dobbs, John M. Drake

Integrative Biology Faculty and Staff Publications

Organic aggregates provide a favorable habitat for aquatic microbes, are efficiently filtered by shellfish, and may play a major role in the dynamics of aquatic pathogens. Quantifying this role requires understanding how pathogen abundance in the water and aggregate size interact to determine the presence and abundance of pathogen cells on individual aggregates. We build upon current understanding of the dynamics of bacteria and bacterial grazers on aggregates to develop a model for the dynamics of a bacterial pathogen species. The model accounts for the importance of stochasticity and the balance between colonization and extinction. Simulation results suggest that while …

Mitochondrial Dna Assessment Of The Phylogeography Of The Gopher Tortoise, Joshua R. Ennen, Brian R. Kreiser, Carl P. Qualls, Daniel Gaillard, Matthew Aresco, Roger Birkhead, Tracey Tuberville, Earl D. Mccoy, Henry R. Mushinsky, Thomas W. "Bill" Hentges, Aaron W. Schrey

Integrative Biology Faculty and Staff Publications

Identifying geographic barriers that define genetic structure within a species is crucial in formulating an effective conservation plan. The identification of appropriate management units is critical for the protection and recovery of the gopher tortoise Gopherus polyphemus, which have declined across their entire range. Previous molecular work at various spatial scales has identified distinct population assemblages of the gopher tortoise. The goal of this study was to assess the genetic structure in gopher tortoises through a more complete sampling of the federally listed as threatened portion of the range and evaluate the extent of genetic isolation imposed by several …

Demasculinization And Feminization Of Male Gonads By Atrazine: Consistent Effects Across Vertebrate Classes, Krista A. Mccoy

Integrative Biology Faculty and Staff Publications

Atrazine is the most commonly detected pesticide contaminant of ground water, surface water, and precipitation. Atrazine is also an endocrine disruptor that, among other effects, alters male reproductive tissues when animals are exposed during development. Here, we apply the nine so-called “Hill criteria” (Strength, Consistency, Specificity, Temporality, Biological Gradient, Plausibility, Coherence, Experiment, and Analogy) for establishing cause–effect relationships to examine the evidence for atrazine as an endocrine disruptor that demasculinizes and feminizes the gonads of male vertebrates. We present experimental evidence that the effects of atrazine on male development are consistent across all vertebrate classes examined and we present a …

Blood-Brain Barrier Impairment In An Animal Model Of Mps Iii B, Svitlana N. Garbuzova-Davis, Michael Louis, Edward M. Haller, Hiranya M. Derasari, Ashley E. Rawls, Paul R. Sanberg

Integrative Biology Faculty and Staff Publications

Background: Sanfilippo syndrome type B (MPS III B) is caused by a deficiency of α-N-acetylglucosaminidase enzyme, leading to accumulation of heparan sulfate within lysosomes and eventual progressive cerebral and systemic multiple organ abnormalities. However, little is known about the competence of the blood-brain barrier (BBB) in MPS III B. BBB dysfunction in this devastating disorder could contribute to neuropathological disease manifestations.

Methodology/Principal Findings: In the present study, we investigated structural (electron microscope) and functional (vascular leakage) integrity of the BBB in a mouse model of MPS III B at different stages of disease, focusing on brain structures known to experience …

Evidence Of Compromised Blood-Spinal Cord Barrier In Early And Late Symptomatic Sod1 Mice Modeling Als, Svitlana N. Garbuzova-Davis, Samuel Saporta, Edward M. Haller, Irina Kolomey, Steven P. Bennett, Huntington Potter, Paul R. Sanberg

Integrative Biology Faculty and Staff Publications

Background: The blood-brain barrier (BBB), blood-spinal cord barrier (BSCB), and blood-cerebrospinal fluid barrier (BCSFB) control cerebral/spinal cord homeostasis by selective transport of molecules and cells from the systemic compartment. In the spinal cord and brain of both ALS patients and animal models, infiltration of T-cell lymphocytes, monocyte-derived macrophages and dendritic cells, and IgG deposits have been observed that may have a critical role in motor neuron damage. Additionally, increased levels of albumin and IgG have been found in the cerebrospinal fluid in ALS patients. These findings suggest altered barrier permeability in ALS. Recently, we showed disruption of the BBB and …

Assessment Of Biogeochemical Deposits In Landfill Drainage Systems, Audrey D. Levine, Valerie J. Harwood, Antonio J. Cardoso, Lisa R. Rhea, Bina S. Nayak, Barbara M. Dodge, Mindy L. Decker, George Dzama, Lawrence Jones, Edward Haller

Integrative Biology Faculty and Staff Publications

Design, operation, and closure practices for Class I municipal solid waste (MSW) landfills are based on RCRA Subtitle D requirements for control of leachates and gases generated during the life of the landfill. Because leachate is generated as a result of water percolating through the landfill and waste consolidation, it contains dissolved and suspended materials that reflect the characteristics of the material it contacts. Over the past two decades significant changes have occurred in the characteristics of the waste streams that are disposed in landfills. In addition, many Florida municipalities have implemented Waste-to-Energy (WTE) systems. The WTE ash is either …

In Situ Of Interferon On Human Glioma Protein Kinase C-Α And -Β Ultrastructural Localization, Mildred Acevedo-Duncan, John Collins, Ruonana Zhang, Edward M. Haller, Charles E. Chalfant, Denise R. Cooper

Integrative Biology Faculty and Staff Publications

Transmission electron microscopy was used to determine how immunogold labeling of PKC-alpha or -beta is modulated by the antitumor drug IFN (HuIFN alpha-2b) in the cytoplasm, membrane structures, and nucleus of rapidly dividing and confluent human glioma U-373 cells. Results showed that except for nuclear localization, there were no specific cytoplasmic organelles that PKC-alpha or -beta translocated to following HuIFN alpha-2b treatment. Electron micrographs of PKC-beta in proliferating cells depicted 1.34-fold more PKC-beta in the nucleus than in the cytoplasm and a 1-min HuIFN alpha-2b (500 units/ml) treatment transiently increased PKC-beta immunoreactivity in the cytoplasm (1.95-fold) and nucleus (1.97-fold). In …

What Controls Tropical Reef Fish Populations: Recruitment Or Benthic Mortality? An Example In The Caribbean Reef Fish Haemulon Flavolineatum, M. J. Shulman, John C. Ogden

Integrative Biology Faculty and Staff Publications

Recruitment from a planktonic larval stage has been proposed to be an important factor in limiting populations of marine organisms, particularly tropical reef fishes. We monitored recruitment and population densities of juvenile size classes In French grunt Haemulon flavolineatum (Haemulidae) from October 1978 through December 1980 In a portion of Tague Bay, St. Croix, U. S. Virgin Islands. Within our study area, 95 % of new recruits settled onto the sand and seagrass lagoon floor and within a few weeks migrated to nearby reefs; the remaining 5'10 settled directly onto reef structures. Mean annual recruitment rate was 1.8 recruits per …

Recruitment Patterns In Young French Grunts, Haemulon Flavolineatum (Family Haemulidae), At St. Croix, Virgin Islands., William N. Mcfarland, E. B. Brothers, John C. Ogden, Myra J. Shulman, E. L. Bermingham, N. M. Kotachian-Prentiss

Integrative Biology Faculty and Staff Publications

No abstract provided.

Herbivory Effects On Thalassia Testudinum Leaf Growth And Nitrogen Content, J. C. Zieman, R. L. Iverson, John C. Ogden

Integrative Biology Faculty and Staff Publications

The pattern of turtle grazing on Thalassia testudinum in St. Croix seagrass beds begins with the establishment of a grazing plot by initial removal of leaf blades, followed by repeated grazing of several centimeter-long leaf blades within a maintained grazing area. Plants within the grazed area exhibit increased specific growth rate as a consequence of increased light flux to unepiphytized leaf bases. Leaf width is reduced in the grazed area as a consequence of grazing stress. The leaf bases contain a higher proportion of nitrogen and a lower lignin content than the leaf tips, in addition to lacking epiphytes. Our …

Scale And Community Structure Of Coral Reef Fishes: A Long-Term Study Of A Large Artificial Reef, John C. Ogden, J. P. Ebersole

Integrative Biology Faculty and Staff Publications

he fish community of a large artificial reef made In 1960 of 800 concrete blocks in a seagrass bed on the south coast of St. John, U.S. Virgin Islands, was studied by comparing a series of visual censuses (1975-1979) with each other and with a 1962 total-poison station collection (Randall, 1963). Discounting the presence of some cryptic species in the poison station that would not normally be seen in visual censuses (N = 10), as well as discounting seagrass-bed residents and roaming species only transient on the reef (N = 13), all of the censuses and the poison station (range …

Grazing And Control Of Coral Reef Community Structure By Diadema Antillarum Philippi (Echinodermata: Echinoidea): A Preliminary Study, P. Sammarco, J. S. Levinton, John C. Ogden

Integrative Biology Faculty and Staff Publications

The grazing activities of the tropical echinoid Diadema antillarum Philippi can markedly influence the structure of the shallow-water epibenthic coral reef community. The elimination of an entire Diadema population from a patch reef in St. Croix, U.S. Virgin Islands resulted in a great increase in macro-algal biomass, alterations in species composition, shifts in dominance, an increase in species numbers, and a decrease in equitability. The increase noted in number of species may be indicative of either initial pre-competitive phases of succession or the creation of a new habitat- the micro-canopy. Experiments involving the caging of Diadema have shown that the …