Life Sciences Commons^™

Jellyfish, Forage Fish, And The World's Major Fisheries, Kelly L. Robinson, James J. Ruzicka, Mary Beth Decker, Richard D. Brodeur, Frank J. Hernandez, Javier Quiñones, E. Marcelo Acha, Shin-Ichi Uye, Hermes Mianzan, William M. Graham

Faculty Publications

A majority of the world’s largest net-based fisheries target planktivorous forage fish that serve as a critical trophic link between the plankton and upper-level consumers such as large predatory fishes, seabirds, and marine mammals. Because the plankton production that drives forage fish also drives jellyfish production, these taxa often overlap in space, time, and diet in coastal ecosystems. This overlap likely leads to predatory and competitive interactions, as jellyfish are effective predators of fish early life stages and zooplankton. The trophic interplay between these groups is made more complex by the harvest of forage fish, which presumably releases jellyfish from …

Proceedings Of The 2014 Midsouth Computational Biology And Bioinformatics Society (Mcbios) Conference, Jonathan D. Wren, Mikhail G. Dozmorov, Dennis Burian, Andy Perkins, Chaoyang Zhang, Peter Hoyt, Rakesh Kaundal

Faculty Publications

No abstract provided.

Antiviral Responses In Mouse Embryonic Stem Cells: Differential Development Of Cellular Mechanisms In Type I Interferon Production And Response, Ruoxing Wang, Jundi Wang, Dhiraj Acharya, Amber M. Paul, Fengwei Bai, Faqing Huang, Yan-Lin Guo

Faculty Publications

We have recently reported that mouse embryonic stem cells (mESCs) are deficient in expressing type I interferons (IFNs) in response to viral infection and synthetic viral RNA analogs (Wang, R., Wang, J., Paul, A. M., Acharya, D., Bai, F., Huang, F., and Guo, Y. L. (2013) J. Biol. Chem. 288, 15926–15936). Here, we report that mESCs are able to respond to type I IFNs, express IFN-stimulated genes, and mediate the antiviral effect of type I IFNs against La Crosse virus and chikungunya virus. The major signaling components in the IFN pathway are expressed in mESCs. Therefore, the basic molecular mechanisms …

Influence Of Resource Levels, Organic Compounds And Laboratory Colonization On Interspecific Competition Between The Asian Tiger Mosquito Aedes Albopictus (Stegomyia Albopicta) And The Southern House Mosquito Culex Quinquefasciatus, D.W. Allgood, Donald A. Yee

Faculty Publications

The mosquitoes Aedes albopictus (Stegomyia albopicta) (Skuse) and Culex quinquefasciatus (Say) (Diptera: Culicidae) are common inhabitants of tyres and other artificial containers, which constitute important peridomestic mosquito breeding habitats. We tested the hypotheses that interspecific resource competition between the larvae of these species is asymmetrical, that the concentration of chemicals associated with decomposing detritus affects the competitive outcomes of these species, and that wild and colonized strains of Cx. quinquefasciatus are affected differently by competition with Ae. albopictus. We conducted two laboratory competition experiments wherein we measured survivorship and estimated population growth (λ′) in both species under …

Molecular Characterization Of Two Opecoelid Trematodes From Fishes In The Gulf Of Mexico, With A Desceiption Of A New Species Of Helicometra, Michael J. Andres, Candis L. Ray, Eric E. Pulis, Stephen S. Curran, Robin M. Overstreet

Faculty Publications

The plagioporine opecoelids Helicometra fasciata (Rudolphi, 1819) Odhner, 1902, and Macvicaria crassigula (Linton, 1910) Bartoli, Bray, and Gibson, 1989 have been reported from fishes in expansive geographic regions, disjointed from their type localities. New material of M. crassigula was collected from near its type locality as well as specimens resembling Helicometra fasciata sensu lato from three triglids in the Gulf of Mexico. Comparisons of the ribosomal DNA (rDNA) sequences, comprising the partial 18S rDNA, internal transcribed spacer region (= ITS1, 5.8S, and ITS2), and partial 28S rDNA gene, from M. crassigula and Helicometra fasciata sensu lato in the Gulf of …

Gelatinous Zooplankton Biomass In The Global Oceans: Geographic Variation And Environmental Drivers, Cathy H. Lucas, Daniel O.B. Jones, Catherine J. Hollyhead, Robert H. Condon, Carlos M. Duarte, William M. Graham, Kelly L. Robinson, Kylie A. Pitt, Mark Schildhauer, Jim Regetz

Faculty Publications

Aim

Scientific debate regarding the future trends, and subsequent ecological, biogeochemical and societal impacts, of gelatinous zooplankton (GZ) in a changing ocean is hampered by lack of a global baseline and an understanding of the causes of biogeographic patterns. We address this by using a new global database of GZ records to test hypotheses relating to environmental drivers of biogeographic variation in the multidecadal baseline of epipelagic GZ biomass in the world's oceans.

Location

Global oceans.

Methods

Over 476,000 global GZ data and metadata items were assembled from a variety of published and unpublished sources. From this, a total of …

Identification And Characterization Of An Operon, Msaabcr, That Controls Virulence And Biofilm Development In Staphlococcus Aureus, Gyan S. Sahukhal, Mohamed O. Elasri

Faculty Publications

Background

Community-acquired, methicillin-resistant Staphylococcus aureus strains often cause localized infections in immunocompromised hosts, but some strains show enhanced virulence leading to severe infections even among healthy individuals with no predisposing risk factors. The genetic basis for this enhanced virulence has yet to be determined. S. aureus possesses a wide variety of virulence factors, the expression of which is carefully coordinated by a variety of regulators. Several virulence regulators have been well characterized, but others have yet to be thoroughly investigated. Previously, we identified the msa gene as a regulator of several virulence genes, biofilm development, and antibiotic resistance. We also …

Large Scale Screening Of Digeneans For Neorickettsia Endosymbionts Using Real-Time Pcr Reveals New Neorickettsia Genotypes, Host Associations And Geographic Records, Stephen Greiman, Vasyl V. Tkach, Eric Pulis, Thomas J. Fayton, Stephen S. Curran

Faculty Publications

Digeneans are endoparasitic flatworms with complex life cycles including one or two intermediate hosts (first of which is always a mollusk) and a vertebrate definitive host. Digeneans may harbor intracellular endosymbiotic bacteria belonging to the genus Neorickettsia (order Rickettsiales, family Anaplasmataceae). Some Neorickettsia are able to invade cells of the digenean's vertebrate host and are known to cause diseases of wildlife and humans. In this study we report the results of screening 771 digenean samples for Neorickettsia collected from various vertebrates in terrestrial, freshwater, brackish, and marine habitats in the United States, China and Australia. Neorickettsia were detected using a …

Interspecific Variation In Juvenile Snapper Otolith Chemical Signatures In The Northern Gulf Of Mexico, William F. Patterson Iii, Beverly K. Barnett, Michelle Zapp Sluis, James Howan Cowan Jr., Alan M. Shiller

Faculty Publications

The objective of this study was to evaluate whether age-0 lane snapper Lutjanus synagris otolith chemical signatures could serve as accurate proxies for those of its congener, red snapper L. campechanus, among northern Gulf of Mexico (GOM) nursery regions. Red (n = 90) and lane (n = 53) snappers were sampled from 3 regions of the northern GOM in fall 2005, and their otolith chemistry was analyzed with sector field-inductively coupled plasma-mass spectrometry (Ba:Ca, Mg:Ca, Mn:Ca, Sr:Ca, Li:Ca) or stable isotope ratio-mass spectrometry (δ¹³C and δ¹⁸O). Chemical signatures were significantly different among regions (MANOVA, p < 0.001) and between species (MANOVA, p = 0.029), with the species effect being driven by significant differences in 4 of the 7 constituents analyzed (ANOVA, p < 0.036). The significant region effect persisted (MANOVA, p < 0.001), but the species effect was non-significant (MANOVA, p = 0.964) when constituent values were normalized to species-specific means. Mean regional classification accuracies from linear discriminant functions computed with otolith constituent data were 84% for lane snapper and 80% for red snapper whether data were normalized or not. Maximum likelihood models parameterized with normalized lane snapper otolith chemistry data estimated red snapper regional composition reasonably well among mixed-region samples (mean error = 9.7% among models). Therefore, it appears age-0 lane snapper otolith chemical signatures can serve as accurate proxies for those of red snapper in the northern GOM. These results have broader implications for deriving natural tags based on otolith chemistry for fishes that may have low abundance in parts of their range.

Contribution Of Surface Leaf-Litter Breakdown And Forest Composition To Benthic Oxygen Demand And Ecosystem Respiration In A South Georgia Blackwater River, Andrew S. Mehring, Kevin A. Kuehn, Cynthia J. Tant, Catherine M. Pringle, R. Richard Lowrance, George Vellidis

Faculty Publications

Many North American blackwater rivers exhibit low dissolved O₂ (DO) that may be the result of benthic respiration. We examined how tree species affected O₂ demand via the quantity and quality of litter produced. In addition, we compared areal estimates of surface leaf-litter microbial respiration to sediment O₂ demand (SOD) and ecosystem respiration (ER) in stream and swamp reaches of a blackwater river to quantify contributions of surface litter decomposition to O₂ demand. Litter inputs averaged 917 and 678 g m⁻² y⁻¹ in the swamp and stream, respectively. Tree species differentially affected O_{2 …}

El Niño-Southern Oscillation Is Linked To Decreased Energetic Condition In Long-Distance Migrants, Kristina Paxton, Emily B. Cohen, Zoltán Németh, Frank R. Moore

Faculty Publications

Predicting how migratory animals respond to changing climatic conditions requires knowledge of how climatic events affect each phase of the annual cycle and how those effects carry-over to subsequent phases. We utilized a 17-year migration dataset to examine how El Niño-Southern Oscillation climatic events in geographically different regions of the Western hemisphere carry-over to impact the stopover biology of several intercontinental migratory bird species. We found that migratory birds that over-wintered in South America experienced significantly drier environments during El Niño years, as reflected by reduced Normalized Difference Vegetation Index (NDVI) values, and arrived at stopover sites in reduced energetic …

Smoq: A Tool For Predicting The Absolute Residue-Specific Quality Of A Single Protein Model With Support Vector Machine, Renzhi Cao, Zheng Wang, Yiheng Wang, Jianlin Cheng

Faculty Publications

Background: It is important to predict the quality of a protein structural model before its native structure is known. The method that can predict the absolute local quality of individual residues in a single protein model is rare, yet particularly needed for using, ranking and refining protein models.

Results: We developed a machine learning tool (SMOQ) that can predict the distance deviation of each residue in a single protein model. SMOQ uses support vector machines (SVM) with protein sequence and structural features (i.e. basic feature set), including amino acid sequence, secondary structures, solvent accessibilities, and residue-residue contacts to …

Designing And Evaluating The Multicom Protein Local And Global Model Quality Prediction Methods In The Casp10 Experiment, Renzhi Cao, Zheng Wang, Jianlin Cheng

Faculty Publications

Background: Protein model quality assessment is an essential component of generating and using protein structural models. During the Tenth Critical Assessment of Techniques for Protein Structure Prediction (CASP10), we developed and tested four automated methods (MULTICOM-REFINE, MULTICOM-CLUSTER, MULTICOM-NOVEL, and MULTICOM-CONSTRUCT) that predicted both local and global quality of protein structural models.

Results: MULTICOM-REFINE was a clustering approach that used the average pairwise structural similarity between models to measure the global quality and the average Euclidean distance between a model and several top ranked models to measure the local quality. MULTICOM-CLUSTER and MULTICOM-NOVEL were two new support vector machine-based …

Transcriptional Activation Of Antioxidants May Compensate For Selenoprotein Deficiences In Amblyomma Maculatum (Acari: Ixodidae) Injected With Selk- Or Selm- Dsrna, S. Adamson, R. Browning, P. Singh, S. Nobles, A. Villareal, Shahid Karim

Faculty Publications

The Gulf‐Coast tick, Amblyomma maculatum, possesses an elaborate set of selenoproteins, which prevent the deleterious effects from oxidative stress that would otherwise occur during feeding. In the current work, we examined the role of selenoprotein K (SelK) and selenoprotein M (SelM) in feeding A. maculatum by bioinformatics, transcriptional gene expression, RNA interference and antioxidant assays. The transcriptional expression of SelK did not vary significantly in salivary glands or midguts throughout the bloodmeal. However, there was a 58‐fold increase in transcript levels of SelM in tick midguts. Ticks injected with selK‐dsRNA or selM‐dsRNA did not reveal any observable …

Improvements In Blood Pressure Among Undiagnosed Hypertensive Participants In A Community-Based Lifestyle Intervention, Mississippi, 2010, Jamie M. Zoellner, Jessica L. Thomson, Alicia S. Landry, Charkarra Anderson-Lewis, Carol Connell, Elaine Fontenot Molaison, Kathleen Yadrick

Faculty Publications

Introduction

Effective strategies are needed to reach and treat people who lack awareness of or have uncontrolled hypertension. We used data from a community-based participatory research initiative, Hub City Steps, to quantify the prevalence of undiagnosed hypertension and determine the relationship between hypertension status at baseline and postintervention improvements in blood pressure and health-related quality of life.

Methods

Hub City Steps was a 6-month preintervention–postintervention lifestyle intervention targeting hypertension risk factors. Outcome measures were collected at baseline, 3 months, and 6 months. Generalized linear mixed models were used to test for effects by time and hypertension status.

Results

Of the …

Health Insurance Status, Psychological Processes, And Older African Americans' Use Of Preventive Care, Catherine Walker O'Neal, Kandauda A.S. Wickrama, Penny A. Ralston, Jasminka Z. Elich, Cynthia M. Harris, Catherine Coccia, Iris Young-Clark, Jennifer Lemacks

Faculty Publications

The current study examined the influence of health insurance, psychological processes (i.e. psychological competency and vulnerability), and the interaction of these two constructs on older African Americans' utilization of five preventive care services (e.g. cholesterol screening and mammogram/prostate examination) using data from 211 older African Americans (median age = 60). In addition to direct effects, the influence of health insurance sometimes varied depending on respondents' psychological competency and/or vulnerability. Policies and interventions to increase older African Americans' use of preventive health services should consider structural (e.g. health insurance) and psychological (e.g. psychological competency and vulnerability) factors along with the interaction …

Hub City Steps: A 6-Month Lifestyle Intervention Improves Blood Pressure Among A Primarily African-American Community, Jamie M. Zoellner, Carol Connell, Michael B. Modson, Jessica L. Thomson, Alicia S. Landry, Elaine Fontenot Molaison, Vickie Blakely Reed, Kathleen Yadrick

Faculty Publications

The effectiveness of community-based participatory research (CBPR) efforts to address the disproportionate burden of hypertension among African Americans remains largely untested. The objective of this 6-month, noncontrolled, pre-/post-experimental intervention was to examine the effectiveness of a CBPR intervention in achieving improvements in blood pressure, anthropometric measures, biological measures, and diet. Conducted in 2010, this multicomponent lifestyle intervention included motivational enhancement, social support provided by peer coaches, pedometer diary self-monitoring, and monthly nutrition and physical activity education sessions. Of 269 enrolled participants, 94% were African American and 85% were female. Statistical analysis included generalized linear mixed models using maximum likelihood estimation. …

Concentrations And Sources Of Polycyclic Aromatic Hydrocarbons In Surface Coastal Sediments Of The Northern Gulf Of Mexico, Zucheng Wang, Zhanfei Liu, Kehui Xu, Lawrence M. Mayer, Zulin Zhang, Alexander S. Kolker, Wei Wu

Faculty Publications

Background: Coastal sediments in the northern Gulf of Mexico have a high potential of being contaminated by petroleum hydrocarbons, such as polycyclic aromatic hydrocarbons (PAHs), due to extensive petroleum exploration and transportation activities. In this study we evaluated the spatial distribution and contamination sources of PAHs, as well as the bioavailable fraction in the bulk PAH pool, in surface marsh and shelf sediments (top 5 cm) of the northern Gulf of Mexico. Results: PAH concentrations in this region ranged from 100 to 856 ng g(-1), with the highest concentrations in Mississippi River mouth sediments followed by marsh sediments and then …

Drosophila Snap-29 Is An Essential Snare That Binds Multiple Proteins Involved In Membrane Traffic, Hao Xu, Mahmood Mohtashami, Bryan Stewart, Gabrielle Boulianne, William S. Trimble

Faculty Publications

Each membrane fusion event along the secretory and endocytic pathways requires a specific set of SNAREs to assemble into a 4-helical coiled-coil, the so-called trans-SNARE complex. Although most SNAREs contribute one helix to the trans-SNARE complex, members of the SNAP-25 family contribute two helixes. We report the characterization of the Drosophila homologue of SNAP-29 (dSNAP-29), which is expressed throughout development. Unlike the other SNAP-25 like proteins in fruit fly (i.e., dSNAP-25 and dSNAP-24), which form SDS-resistant SNARE complexes with their cognate SNAREs, dSNAP-29 does not participate in any SDS-resistant complexes, despite its interaction with dsyntaxin1 and dsyntaxin 16 in vitro. …

Structural And Functional Analyses Of A Glutaminyl Cyclase From Ixodes Scapularis Reveal Metal-Independent Catalysis And Inhibitor Binding, Kai-Fa Huang, Hui-Ling Hsu, Shahid Karim, Andrew H.-J. Wang

Faculty Publications

Glutaminyl cyclases (QCs) from mammals and Drosophila are zinc-dependent enzymes that catalyze N-terminal pyroglutamate formation of numerous proteins and peptides. These enzymes have been found to be critical for the oviposition and embryogenesis of ticks, implying that they are possible physiological targets for tick control. Here, 1.10–1.15 Å resolution structures of a metal-independent QC from the black-legged tick Ixodes scapularis (Is-QC) are reported. The structures exhibit the typical scaffold of mammalian QCs but have two extra disulfide bridges that stabilize the central β-­sheet, resulting in an increased thermal stability. Is-QC contains ∼0.5 stoichiometric zinc ions, which could …

Priming In The Microbial Landscape: Periphytic Algal Stimulation Of Litter-Associated Microbial Decomposers, Kevin A. Kuehn, Steven N. Francoeur, Robert H. Findlay, Robert K. Neely

Faculty Publications

Microbial communities associated with submerged detritus in aquatic ecosystems often comprise a diverse mixture of autotrophic and heterotrophic microbes, including algae, bacteria, protozoa, and fungi. Recent studies have documented increased rates of plant litter mass loss when periphytic algae are present. We conducted laboratory and field experiments to assess potential metabolic interactions between natural autotrophic and heterotrophic microbial communities inhabiting submerged decaying plant litter of Typha angustifolia and Schoenoplectus acutus. In the field, submerged plant litter was either exposed to natural sunlight or placed under experimental canopies that manipulated light availability and growth of periphytic algae. Litter was collected …

Culture Of Lobotes Surinamensis (Tripletail), Eric Saillant, Jason T. Lemus, James S. Franks

Faculty Publications

No abstract provided.

Importation Of Exotic Ticks And Tick-Borne Spotted Fever Group Rickettsiae Into The United States By Migrating Songbirds, Nabanita Mukherjee, Lorenza Beati, Michael Sellers, Laquita Burton, Steven Adamson, Richard G. Robbins, Frank Moore, Shahid Karim

Faculty Publications

Birds are capable of carrying ticks and, consequently, tick-transmitted microorganisms over long distances and across geographical barriers such as oceans and deserts. Ticks are hosts for several species of spotted fever group rickettsiae (SFGR), which can be transmitted to vertebrates during blood meals. In this study, the prevalence of this group of rickettsiae was examined in ticks infesting migratory songbirds by using polymerase chain reaction (PCR). During the 2009 and 2010 spring migration season, 2064 northward-migrating passerine songbirds were examined for ticks at Johnson Bayou, Louisiana. A total of 91 ticks was removed from 35 individual songbirds for tick species …

Effects Of Landscape Composition And Configuration On Migrating Songbirds: Inference From An Individual-Based Model, Emily B. Cohen, Scott M. Pearson, Frank R. Moore

Faculty Publications

The behavior of long-distance migrants during stopover is constrained by the need to quickly and safely replenish energetic reserves. Replenishing fuel stores at stopover sites requires adjusting to unfamiliar landscapes with little to no information about the distribution of resources. Despite their critical importance to the success of songbird migration, the effects of landscape composition and configuration on fuel deposition rates (FDR [g/d]), the currency of migration, has not been tested empirically. Our objectives were to understand the effects of heterogeneous landscapes on FDR of forest-dwelling songbirds during spring migration. The results of field experiments were used to parameterize a …

Interspecific Competition Of A New Invasive Mosquito, Culex Coronator, And Two Container Mosquitoes, Aedes Albopictus And Cx. Quinquefasciatus (Diptera: Culicidae), Across Different Detritus Environments, D. A. Yee, J. F. Skiff

Faculty Publications

The mosquito Culex coronator (Dyar and Knab) (Diptera: Culicidae) has undergone rapid range expansion in the United States since 2003, with its historical distribution in the southwest expanding eastward to the Atlantic coast. Although Cx. coronator nominally use small natural aquatic habitats for development, the use of containers (e.g., tires) makes it potentially important as container invasive. To determine the potential ecological effects of Cx. coronator on resident container species, we conducted a laboratory experiment to assess its competitive ability with two common tire-inhabiting species, Aedes albopictus (Skuse) and Culex quinquefasciatus (Say) (Diptera: Culicidae). Larvae were reared under a factorial …

An Insight Into The Microbiome Of The Amblyomma Maculatum(Acari: Ixodidae), Khemraj Budachetri, Rebecca E. Browning, Steven W. Adamson, Scot E. Dowd, Chien-Chung Chao, Wei-Mei Ching, Shahid Karim

Faculty Publications

The aim of this study was to survey the bacterial diversity of Amblyomma maculatum Koch, 1844, and characterize its infection with Rickettsia parkeri. Pyrosequencing of the bacterial 16S rRNA was used to determine the total bacterial population in A. maculatum. Pyrosequencing analysis identified Rickettsia in A. maculatum midguts, salivary glands, and saliva, which indicates successful trafficking in the arthropod vector. The identity of Rickettsia spp. was determined based on sequencing the rickettsial outer membrane protein A (rompA) gene. The sequence homology search revealed the presence of R. parkeri, Rickettsia amblyommii, and Rickettsia endosymbiont of …

Effects Of Coastal Urbanization On Salt-Marsh Faunal Assemblages In The Northern Gulf Of Mexico, Michael R. Lowe, Mark S. Peterson

Faculty Publications

Coastal landscapes in the northern Gulf of Mexico, specifically the Mississippi coast, have undergone rapid urbanization that may impact the suitability of salt-marsh ecosystems for maintaining and regulating estuarine faunal communities. We used a landscape ecology approach to quantify the composition and configuration of salt-marsh habitats and developed surfaces at multiple spatial scales surrounding three small, first-order salt-marsh tidal creeks arrayed along a gradient of urbanization in two river-dominated estuaries. From May 3 to June 4, 2010, nekton and macroinfauna were collected weekly at all six sites. Due to the greater abundance of grass shrimp Palaemonetes spp., brown shrimp Farfantepenaeus …