294 research outputs found

    Food Habits and Dietary Overlap of Newly Settled Red Drum (Sciaenops ocellatus) and Atlantic Croaker (Micropogonias undulatus) from Texas Seagrass Meadows

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    Food habits and dietary overlap of newly settled larval and juvenile red drum and Atlantic croaker were examined during the period when the two species co-occur in seagrass nurseries. A total of 274 red drum (4.00 - 19.99 mm SL) and 205 Atlantic croaker (8.00 - 17.99 mm SL) were used for this analysis. Of the red drum stomachs examined, 8.4% were empty while 28.8% of Atlantic croaker stomachs contained no food. Major prey items identified for both species were calanoid copepods, harpacticoid copepods and mysid shrimp across all size classes. Ontogenetic trophic niche shifts were detected for red drum and Atlantic croaker. Type and quantity of food ingested by red drum were similar across all stations (Aransas Bay Station: 1H, 2T and 3H) examined. Atlantic croaker ingested the same types of prey at all stations, but contained varying quantities of food throughout the study area. In general, high dietary overlap was observed between red drum and Atlantic croaker with most overlap values (Schoener’s index) exceeding 70%

    Helicobacter pylori Lipopolysaccharide Is Synthesized via a Novel Pathway with an Evolutionary Connection to Protein N-Glycosylation

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    Lipopolysaccharide (LPS) is a major component on the surface of Gram negative bacteria and is composed of lipid A-core and the O antigen polysaccharide. O polysaccharides of the gastric pathogen Helicobacter pylori contain Lewis antigens, mimicking glycan structures produced by human cells. The interaction of Lewis antigens with human dendritic cells induces a modulation of the immune response, contributing to the H. pylori virulence. The amount and position of Lewis antigens in the LPS varies among H. pylori isolates, indicating an adaptation to the host. In contrast to most bacteria, the genes for H. pylori O antigen biosynthesis are spread throughout the chromosome, which likely contributed to the fact that the LPS assembly pathway remained uncharacterized. In this study, two enzymes typically involved in LPS biosynthesis were found encoded in the H. pylori genome; the initiating glycosyltransferase WecA, and the O antigen ligase WaaL. Fluorescence microscopy and analysis of LPS from H. pylori mutants revealed that WecA and WaaL are involved in LPS production. Activity of WecA was additionally demonstrated with complementation experiments in Escherichia coli. WaaL ligase activity was shown in vitro. Analysis of the H. pylori genome failed to detect a flippase typically involved in O antigen synthesis. Instead, we identified a homolog of a flippase involved in protein N-glycosylation in other bacteria, although this pathway is not present in H. pylori. This flippase named Wzk was essential for O antigen display in H. pylori and was able to transport various glycans in E. coli. Whereas the O antigen mutants showed normal swimming motility and injection of the toxin CagA into host cells, the uptake of DNA seemed to be affected. We conclude that H. pylori uses a novel LPS biosynthetic pathway, evolutionarily connected to bacterial protein N-glycosylation

    Fish assemblages associated with artificial reefs assessed using multiple gear types in the northwest Gulf of Mexico

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    Quantitative surveys of fishes associated with artificial reefs in the northwest Gulf of Mexico were conducted over a 4-yr period (2014-2017). Artificial reefs surveyed were comprised of three types: concrete structures, rig jackets, and decommissioned ships. All reefs were surveyed using vertical long line ( VLL), fish traps, and Adaptive Resolution Imaging Sonar (ARIS 1800). Mean fish abundance did not significantly differ using VLL [1.7 ind set(-1) (SD 2.2)] among the three reef types. However, relative abundance among all fishes collected was significantly highest on rig reefs using traps [6.2 ind soak(-1) (SD 3.8)], while results from sonar surveys indicated that the mean relative fish density was highest on concrete reefs [15.3 fish frame(-1) (SD 26.8)]. Red snapper (n = 792), followed by gray triggerfish (n = 130), pigfish (n = 70), tomtate (n = 69), and hardhead catfish (n = 57) were the most numerically abundant species using VLL and traps; red snapper comprised 90.7% of total catch using VLL and 43.9% using traps. Mean Brillouin\u27s diversity (HB) was highest on ships using VLL [0.41 (SD 0.14)] and highest on rigs using traps [0.87 (SD 0.58)] compared to the lowest diversity found on concrete [VLL 0.07 (SD 0.11); traps 0.36 (SD 0.32)]. Findings from this study can be used to inform the planning of future artificial reefs and their effect on the assemblages of reef-associated fishes. Additionally, these results highlight the value of using multiple gear types to survey reef fish assemblages associated with artificial reefs

    Natural geochemical markers reveal environmental history and population connectivity of common cuttlefish in the Atlantic Ocean and Mediterranean Sea

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    Natural markers (delta C-13 and delta O-18 stable isotopes) in the cuttlebones of the European common cuttlefish (Sepia officinalis) were determined for individuals collected across a substantial portion of their range in the Northeast Atlantic Ocean (NEAO) and Mediterranean Sea. Cuttlebone delta C-13 and delta O-18 were quantified for core and edge material to characterize geochemical signatures associated with early (juvenile) and recent (sub-adult/adult) life-history periods, respectively. Regional shifts in cuttlebone delta C-13 and delta O-18 values were detected across the 12 sites investigated. Individuals collected from sites in the NEAO displayed more enriched delta C-13 and delta O-18 values relative to sites in the Mediterranean Sea, with the latter also showing salient differences in both markers among western, central and eastern collection areas. Classification success based on cuttlebone delta C-13 and delta O-18 values to four geographical regions (NEAO, western, central and eastern Mediterranean Sea) was relatively high, suggesting that environmental conditions in each region were distinct and produced area-specific geochemical signatures on the cuttlebones ofS. officinalis. A modified delta C-13 and delta O-18 baseline was developed from sites proximal to the Strait of Gibraltar in both the NEAO and Mediterranean Sea to assess potential mixing through this corridor. Nearly, all (95%) of delta C-13 and delta O-18 signatures ofS. officinaliscollected in the area of the NEAO closest to the Strait of Gibraltar (Gulf of Cadiz) matched the signatures of specimens collected in the western Mediterranean, signifying potential movement and mixing of individuals through this passageway. This study extends the current application of these geochemical markers for assessing the natal origin and population connectivity of this species and potentially other taxa that inhabit this geographical area.Portuguese Foundation for Science and Technology: IF/00576/2014info:eu-repo/semantics/publishedVersio

    Sex-Based Differences in Outcomes After Hip Arthroscopic Surgery for Femoroacetabular Impingement: A Systematic Review

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    A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author's publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.Background: While sex-based differences in outcomes after hip arthroscopic surgery for femoroacetabular impingement syndrome (FAIS) are often recorded, no studies have been dedicated to analyzing the literature as a whole. Purpose: To investigate whether sex is a predictor of outcomes in studies evaluating hip arthroscopic surgery for FAIS. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We searched the PubMed, Embase, Cochrane, Ovid, and PubMed Central databases for English-language studies that evaluated sex-specific outcomes in human populations. The search terms used were as follows: (“Hip Arthroscopy”) AND (“Femoroacetabular Impingement” OR “FAI”) AND (“Sex” OR “Gender” OR “Male” OR “Female”). Studies with evidence levels 2 through 4 were included. The studies were then screened, followed by data extraction. Modified Harris Hip Score (mHHS) outcomes and return-to-sport (RTS) rates were recorded. These were analyzed using random-effects meta-analysis. Heterogeneity was calculated using the I2 statistic. Results: Of 256 full-text articles screened, 48 articles were included in this analysis; of these, 14 studies (29%) concluded that female sex was a negative predictor of postoperative outcomes, while 6 studies (13%) found female sex to be positive predictor. The remaining 28 studies (58%) found no sex-based differences in postoperative outcomes. Of 7 studies (416 male and 519 female) included in the mHHS analysis, 2 studies concluded that male patients had significantly higher postoperative mHHS scores. Of 6 studies (502 male and 396 female) included in the RTS analysis, 1 study concluded that male patients had a significantly higher RTS rate. Conclusion: Almost one-third of the included studies determined that female sex was a negative predictor of postoperative outcomes, 13% found female sex to be a positive predictor, and 58% found no sex-based differences. Our study illustrates an insufficiency of high-level evidence supporting sex-specific differences in outcomes after hip arthroscopic surgery, but findings indicated that the postoperative mHHS score and RTS rate may be influenced by sex

    Listening In on the Past: What Can Otolith δ18O Values Really Tell Us about the Environmental History of Fishes?

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    Oxygen isotope ratios from fish otoliths are used to discriminate marine stocks and reconstruct past climate, assuming that variations in otolith δ18O values closely reflect differences in temperature history of fish when accounting for salinity induced variability in water δ18O. To investigate this, we exploited the environmental and migratory data gathered from a decade using archival tags to study the behaviour of adult plaice (Pleuronectes platessa L.) in the North Sea. Based on the tag-derived monthly distributions of the fish and corresponding temperature and salinity estimates modelled across three consecutive years, we first predicted annual otolith δ18O values for three geographically discrete offshore sub-stocks, using three alternative plausible scenarios for otolith growth. Comparison of predicted vs. measured annual δ18O values demonstrated >96% correct prediction of sub-stock membership, irrespective of the otolith growth scenario. Pronounced inter-stock differences in δ18O values, notably in summer, provide a robust marker for reconstructing broad-scale plaice distribution in the North Sea. However, although largely congruent, measured and predicted annual δ18O values of did not fully match. Small, but consistent, offsets were also observed between individual high-resolution otolith δ18O values measured during tag recording time and corresponding δ18O predictions using concomitant tag-recorded temperatures and location-specific salinity estimates. The nature of the shifts differed among sub-stocks, suggesting specific vital effects linked to variation in physiological response to temperature. Therefore, although otolith δ18O in free-ranging fish largely reflects environmental temperature and salinity, we counsel prudence when interpreting otolith δ18O data for stock discrimination or temperature reconstruction until the mechanisms underpinning otolith δ18O signature acquisition, and associated variation, are clarified

    Cascade and anti-Cascade Polarization Measurements at 800 GeV/c

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    The polarization of neutral Cascade and anti-Cascade hyperons produced by 800 GeV/c protons on a BeO target at a fixed targeting angle of 4.8 mrad is measured by the KTeV experiment at Fermilab. Our result of 9.7% for the neutral Cascade polarization shows no significant energy dependence when compared to a result obtained at 400 GeV/c production energy and at twice our targeting angle. The polarization of the neutral anti-Cascade is measured for the first time and found to be consistent with zero. We also examine the dependence of polarization on transverse production momentum.Comment: 4 page PR

    Population Connectivity of Pelagic Megafauna in the Cuba-Mexico-United States Triangle

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    The timing and extent of international crossings by billfishes, tunas, and sharks in the Cuba-Mexico-United States (U.S.) triangle was investigated using electronic tagging data from eight species that resulted in \u3e22,000 tracking days. Transnational movements of these highly mobile marine predators were pronounced with varying levels of bi- or tri-national population connectivity displayed by each species. Billfishes and tunas moved throughout the Gulf of Mexico and all species investigated (blue marlin, white marlin, Atlantic bluefin tuna, yellowfin tuna) frequently crossed international boundaries and entered the territorial waters of Cuba and/or Mexico. Certain sharks (tiger shark, scalloped hammerhead) displayed prolonged periods of residency in U.S. waters with more limited displacements, while whale sharks and to a lesser degree shortfin mako moved through multiple jurisdictions. The spatial extent of associated movements was generally associated with their differential use of coastal and open ocean pelagic ecosystems. Species with the majority of daily positions in oceanic waters off the continental shelf showed the greatest tendency for transnational movements and typically traveled farther from initial tagging locations. Several species converged on a common seasonal movement pattern between territorial waters of the U.S. (summer) and Mexico (winter)
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