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Full-Text Articles in Life Sciences

Environmental Pseudomonads Inhibit Cystic Fibrosis Patient-Derived Pseudomonas Aeruginosa, Payel Chatterjee, Elizabeth Davis, Fengan Yu, Sarah James, Julia H. Wildschutte, Daniel D. Wiegmann, David H. Sherman, Robert M. Mckay, John J. Lipuma, Hans Wildschutte Jan 2017

Environmental Pseudomonads Inhibit Cystic Fibrosis Patient-Derived Pseudomonas Aeruginosa, Payel Chatterjee, Elizabeth Davis, Fengan Yu, Sarah James, Julia H. Wildschutte, Daniel D. Wiegmann, David H. Sherman, Robert M. Mckay, John J. Lipuma, Hans Wildschutte

Great Lakes Institute for Environmental Research Publications

Pseudomonas aeruginosa is an opportunistic pathogen which is evolving resistance to many currently used antibiotics. While much research has been devoted to the roles of pathogenic P. aeruginosa in cystic fibrosis (CF) patients, less is known of its ecological properties. P. aeruginosa dominates the lungs during chronic infection in CF patients, yet its abundance in some environments is less than that of other diverse groups of pseudomonads. Here, we sought to determine if clinical isolates of P. aeruginosa are vulnerable to environmental pseudomonads that dominate soil and water habitats in one-to-one competitions which may provide a source of inhibitory factors. …


Identification, Enumeration And Diversity Of Nitrifying Planktonic Archaea And Bacteria In Trophic End Members Of The Laurentian Great Lakes, Maitreyee Mukherjee, Anirban Ray, Anton F. Post, Robert Michael Mckay, George S. Bullerjahn Feb 2016

Identification, Enumeration And Diversity Of Nitrifying Planktonic Archaea And Bacteria In Trophic End Members Of The Laurentian Great Lakes, Maitreyee Mukherjee, Anirban Ray, Anton F. Post, Robert Michael Mckay, George S. Bullerjahn

Great Lakes Institute for Environmental Research Publications

Oligotrophic Lake Superior and mesotrophic Lake Erie are trophic end members of the hydrologically connected Laurentian Great Lakes system, and as such exhibit different profiles of dissolved nitrogen species. Nitrification in Lake Superior has led to increasing nitrate concentrations over the past century, as opposed to Erie, where nitrate inventories have declined due to denitrification. In this study, we examined the abundance and diversity of nitrifying microbes involved in the oxidation of ammonia to nitrite, and nitrite to nitrate. By in situ hybridization methods, we enumerated the major planktonic ammonia oxidizing bacteria (AOB) and archaea (AOA) during a July 2011 …


Latitudinal Variation In Ecological Opportunity And Intraspecific Competition Indicates Differences In Niche Variability And Diet Specialization Of Arctic Marine Predators, David J. Yurkowski, Steven Ferguson, Emily S. Choy, Lisa L. Loseto, Tanya M. Brown, Derek Cg Muir, Christina Ad Semeniuk, Aaron T. Fisk Jan 2016

Latitudinal Variation In Ecological Opportunity And Intraspecific Competition Indicates Differences In Niche Variability And Diet Specialization Of Arctic Marine Predators, David J. Yurkowski, Steven Ferguson, Emily S. Choy, Lisa L. Loseto, Tanya M. Brown, Derek Cg Muir, Christina Ad Semeniuk, Aaron T. Fisk

Great Lakes Institute for Environmental Research Publications

Individual specialization (IS), where individuals within populations irrespective of age, sex, and body size are either specialized or generalized in terms of resource use, has implications on ecological niches and food web structure. Niche size and degree of IS of near-top trophic-level marine predators have been little studied in polar regions or with latitude. We quantified the largescale latitudinal variation of population- and individual-level niche size and IS in ringed seals (Pusa hispida) and beluga whales (Delphinapterus leucas) using stable carbon and nitrogen isotope analysis on 379 paired ringed seal liver and muscle samples and 124 paired beluga skin and …


Employing Individual Measures Of Baseline Glucocorticoids As Population-Level Conservation Biomarkers: Considering Within-Individual Variation In A Breeding Passerine, Christine L. Madliger, Oliver P. Love Jan 2016

Employing Individual Measures Of Baseline Glucocorticoids As Population-Level Conservation Biomarkers: Considering Within-Individual Variation In A Breeding Passerine, Christine L. Madliger, Oliver P. Love

Great Lakes Institute for Environmental Research Publications

Labile physiological variables, such as stress hormones [i.e. glucocorticoids (GCs)], allow individuals to react to perturbations in their environment and may therefore reflect the effect of disturbances or positive conservation initiatives in advance of population-level demographic measures. Although the application of GCs as conservation biomarkers has been of extensive interest, few studies have explicitly investigated whether baseline GC concentrations respond to disturbances consistently across individuals. However, confirmation of consistent responses is of paramount importance to assessing the ease of use of GCs in natural systems and to making valid interpretations regarding population-level change (or lack of change) in GC concentrations. …


Temporal Overlap And Repeatability Of Feather Corticosterone Levels: Practical Considerations For Use As A Biomarker, Christopher M. Harris, Christine L. Madliger, Oliver P. Love Jan 2016

Temporal Overlap And Repeatability Of Feather Corticosterone Levels: Practical Considerations For Use As A Biomarker, Christopher M. Harris, Christine L. Madliger, Oliver P. Love

Great Lakes Institute for Environmental Research Publications

The measurement of corticosterone (CORT) levels in feathers has recently become an appealing tool for the conservation toolbox, potentially providing a non-invasive, integrated measure of stress activity throughout the time of feather growth. However, because the mechanism of CORT deposition, storage and stability in feathers is not fully understood, it is unclear how reliable this measure may be, especially when there is an extended interval between growth and feather collection. We compared CORT levels of naturally grown feathers from tree swallows (Tachycineta bicolor) that were moulted and regrown concurrently and therefore expected to have similar CORT levels. Specifically, we compared …


Determination Of The Gut Retention Of Plastic Microbeads And Microfibers In Goldfish 1 (Carassius Auratus), Stefan Grigorakis, Sherri A. Mason, Ken G. Drouillard Jan 2016

Determination Of The Gut Retention Of Plastic Microbeads And Microfibers In Goldfish 1 (Carassius Auratus), Stefan Grigorakis, Sherri A. Mason, Ken G. Drouillard

Great Lakes Institute for Environmental Research Publications

Microplastics are ubiquitous pollutants in aquatic habitats and commonly found in the gut contents of fish yet relatively little is known about the retention of these particles by fish. In this study, goldfish were fed a commercial fish food pellet amended with 50 particles of one of two microplastics types, microbeads and microfibers. Microbeads were obtained from a commercial facial cleanser while microfibers were obtained from washed synthetic textile. Following consumption of the amended pellet, fish were allowed to feed to satiation on non-amended food followed by fasting for periods ranging from 1.5 h to 6 days. Fish sacrificed at …


Global Solutions To Regional Problems: Collecting Global Expertise To Address The Problem Of Harmful Cyanobacterial Blooms. A Lake Erie Case Study, George S. Bullerjahn, Robert M. Mckay, Timothy W. Davis, David B. Baker, Gregory L. Boyer, Lesley V. D'Anglada, Gregory J. Doucette, Jeff C. Ho, Elena G. Irwin, Catherine L. Kling, Raphael M. Kudela, Rainer Kurmayer, Anna M. Michalak, Joseph D. Ortiz, Timothy G. Otten, Hans W. Paerl, Boqiang Qin, Brent L. Sohngen Jan 2016

Global Solutions To Regional Problems: Collecting Global Expertise To Address The Problem Of Harmful Cyanobacterial Blooms. A Lake Erie Case Study, George S. Bullerjahn, Robert M. Mckay, Timothy W. Davis, David B. Baker, Gregory L. Boyer, Lesley V. D'Anglada, Gregory J. Doucette, Jeff C. Ho, Elena G. Irwin, Catherine L. Kling, Raphael M. Kudela, Rainer Kurmayer, Anna M. Michalak, Joseph D. Ortiz, Timothy G. Otten, Hans W. Paerl, Boqiang Qin, Brent L. Sohngen

Great Lakes Institute for Environmental Research Publications

In early August 2014, the municipality of Toledo, OH (USA) issued a ‘do not drink’ advisory on their water supply directly affecting over 400,000 residential customers and hundreds of businesses (Wilson, 2014). This order was attributable to levels of microcystin, a potent liver toxin, which rose to 2.5 μg L−1 in finished drinking water. The Toledo crisis afforded an opportunity to bring together scientists from around the world to share ideas regarding factors that contribute to bloom formation and toxigenicity, bloom and toxin detection as well as prevention and remediation of bloom events. These discussions took place at an NSF- …


Close Proximity Detection Interference With Acoustic Telemetry: The Importance Of Considering Tag Power Output In Low Ambient Noise Environments, Steven Thomas Kessel, Nigel Edward Hussey, Dale Mitchell Webber, Samuel Harvey Gruber, Joy Michelle Young, Malcolm John Smale, Aaron T. Fisk Mar 2015

Close Proximity Detection Interference With Acoustic Telemetry: The Importance Of Considering Tag Power Output In Low Ambient Noise Environments, Steven Thomas Kessel, Nigel Edward Hussey, Dale Mitchell Webber, Samuel Harvey Gruber, Joy Michelle Young, Malcolm John Smale, Aaron T. Fisk

Great Lakes Institute for Environmental Research Publications

When employing acoustic telemetry to study aquatic species, understanding the functional dynamics of the monitoring system is essential for effective study design, data interpretation, and analysis. Typically, researchers are concerned with maximum effective detection range and consequently tend to employ the largest most powerful tags the study species can carry without considerable energetic burden. In ideal acoustic conditions of low ambient noise environments, low attenuation, and reflective structure, higher powered tags can be detected at larger distances from the receiver, but they can also be subject to the phenomenon ‘Close Proximity Detection Interference’ (CPDI). This occurs when reflective barriers, such …


Abundance And Diversity Of Ammonia-Oxidizing Archaea And Bacteria In Sediments Of Trophic End Members Of The Laurentian Great Lakes, Erie And Superior, Annette Bollmann, George S. Bullerjahn, Robert Michael Mckay May 2014

Abundance And Diversity Of Ammonia-Oxidizing Archaea And Bacteria In Sediments Of Trophic End Members Of The Laurentian Great Lakes, Erie And Superior, Annette Bollmann, George S. Bullerjahn, Robert Michael Mckay

Great Lakes Institute for Environmental Research Publications

Ammonia oxidation is the first step of nitrification carried out by ammonia-oxidizing Archaea (AOA) and Bacteria (AOB). Lake Superior and Erie are part of the Great Lakes system differing in trophic status with Lake Superior being oligotrophic and Lake Erie meso- to eutrophic. Sediment samples were collected from both lakes and used to characterize abundance and diversity of AOA and AOB based on the ammonia monooxygenase (amoA) gene. Diversity was accessed by a pyro-sequencing approach and the obtained sequences were used to determine the phylogeny and alpha and beta diversity of the AOA and AOB populations. In Lake Erie copy …


Spatial Variability In Iron Nutritional Status Of Large Diatoms In The Sea Of Okhotsk With Special Reference To The Amur River Discharge, K. Suzuki, A. Hattori-Saito, Y. Sekiguchi, J. Nishioka, M. Shigemitsu, T. Isada, H. Liu, R. M.L. Mckay May 2014

Spatial Variability In Iron Nutritional Status Of Large Diatoms In The Sea Of Okhotsk With Special Reference To The Amur River Discharge, K. Suzuki, A. Hattori-Saito, Y. Sekiguchi, J. Nishioka, M. Shigemitsu, T. Isada, H. Liu, R. M.L. Mckay

Great Lakes Institute for Environmental Research Publications

The Sea of Okhotsk is known as one of the most biologically productive regions among the world's oceans, and its productivity is supported in part by the discharge of iron (Fe)-rich water from the Amur River. However, little is known about the effect of riverine-derived Fe input on the physiology of the large diatoms which often flourish in surface waters of the productive continental shelf region. We conducted diatom-specific immunochemical ferredoxin (Fd) and flavodoxin (Fld) assays in order to investigate the spatial variability of Fe nutritional status in the microplankton-sized (20-200 1/4m; hereafter micro-sized) diatoms. The Fd index, defined as …


The Last Frontier: Catch Records Of White Sharks (Carcharodon Carcharias) In The Northwest Pacific Ocean, Heather M. Christianson, Victor Lin, Sho Tanaka, Anatoly Velikanov, Henry F. Mollet, Sabine T. Wintner, Sonja V. Fordham, Aaron T. Fisk, Nigel E. Hussey Apr 2014

The Last Frontier: Catch Records Of White Sharks (Carcharodon Carcharias) In The Northwest Pacific Ocean, Heather M. Christianson, Victor Lin, Sho Tanaka, Anatoly Velikanov, Henry F. Mollet, Sabine T. Wintner, Sonja V. Fordham, Aaron T. Fisk, Nigel E. Hussey

Great Lakes Institute for Environmental Research Publications

White sharks are highly migratory apex predators, globally distributed in temperate, sub-tropical, and tropical waters. Knowledge of white shark biology and ecology has increased recently based on research at known aggregation sites in the Indian, Atlantic, and Northeast Pacific Oceans; however, few data are available for the Northwest Pacific Ocean. This study provides a meta-analysis of 240 observations of white sharks from the Northwest Pacific Ocean between 1951 and 2012. Records comprise reports of bycatch in commercial fisheries, media accounts, personal communications, and documentation of shark-human interactions from Russia (n = 8), Republic of Korea (22), Japan (129), China (32), …


Seasonal Changes In Microbial Community Structure And Activity Imply Winter Production Is Linked To Summer Hypoxia In A Large Lake, Steven W. Wilhelm, Gary R. Lecleir, George S. Bullerjahn, Robert M. Mckay, Matthew A. Saxton, Michael R. Twiss, Richard A. Bourbonniere Feb 2014

Seasonal Changes In Microbial Community Structure And Activity Imply Winter Production Is Linked To Summer Hypoxia In A Large Lake, Steven W. Wilhelm, Gary R. Lecleir, George S. Bullerjahn, Robert M. Mckay, Matthew A. Saxton, Michael R. Twiss, Richard A. Bourbonniere

Great Lakes Institute for Environmental Research Publications

Carbon and nutrient cycles in large temperate lakes such as Lake Erie are primarily driven by phototrophic and heterotrophic microorganisms, although our understanding of these is often constrained to late spring through summer due to logistical constraints. During periods of > 90% ice cover in February of 2008, 2009, and 2010, we collected samples from an icebreaker for an examination of bacterial production as well as microbial community structure. In comparison with summer months (August 2002 and 2010), we tested hypotheses concerning seasonal changes in microbial community diversity and production. Bacterial production estimates were c. 2 orders of magnitude higher (volume …


Variable Δ15n Diet-Tissue Discrimination Factors Among Sharks: Implications For Trophic Position, Diet And Food Web Models, Jill A. Olin, Nigel E. Hussey, Alice Grgicak-Mannion, Mark W. Fritts, Sabine T. Wintner, Aaron T. Fisk Oct 2013

Variable Δ15n Diet-Tissue Discrimination Factors Among Sharks: Implications For Trophic Position, Diet And Food Web Models, Jill A. Olin, Nigel E. Hussey, Alice Grgicak-Mannion, Mark W. Fritts, Sabine T. Wintner, Aaron T. Fisk

Great Lakes Institute for Environmental Research Publications

The application of stable isotopes to characterize the complexities of a species foraging behavior and trophic relationships is dependent on assumptions of δ15N diet-tissue discrimination factors (∆15N). As ∆15N values have been experimentally shown to vary amongst consumers, tissues and diet composition, resolving appropriate speciesspecific ∆15N values can be complex. Given the logistical and ethical challenges of controlled feeding experiments for determining ∆ 15N values for large and/or endangered species, our objective was to conduct an assessment of a range of reported ∆ 15N values that can hypothetically serve as surrogates for describing the predator-prey relationships of four shark species …


Diatom Assemblages Promote Ice Formation In Large Lakes, N. A. D'Souza, Y. Kawarasaki, J. D. Gantz, R. E. Lee, B. F.N. Beall, Y. M. Shtarkman, Z. A. Koçer, S. O. Rogers, H. Wildschutte, G. S. Bullerjahn, R. M.L. Mckay Aug 2013

Diatom Assemblages Promote Ice Formation In Large Lakes, N. A. D'Souza, Y. Kawarasaki, J. D. Gantz, R. E. Lee, B. F.N. Beall, Y. M. Shtarkman, Z. A. Koçer, S. O. Rogers, H. Wildschutte, G. S. Bullerjahn, R. M.L. Mckay

Great Lakes Institute for Environmental Research Publications

We present evidence for the directed formation of ice by planktonic communities dominated by filamentous diatoms sampled from the ice-covered Laurentian Great Lakes. We hypothesize that ice formation promotes attachment of these non-motile phytoplankton to overlying ice, thereby maintaining a favorable position for the diatoms in the photic zone. However, it is unclear whether the diatoms themselves are responsible for ice nucleation. Scanning electron microscopy revealed associations of bacterial epiphytes with the dominant diatoms of the phytoplankton assemblage, and bacteria isolated from the phytoplankton showed elevated temperatures of crystallization (T c) as high as -3 °C. Ice nucleation-active bacteria were …


Rates And Controls Of Nitrification In A Large Oligotrophic Lake, Gaston E. Small, George S. Bullerjahn, Robert W. Sterner, Benjamin F.N. Beall, Sandra Brovold, Jacques C. Finlay, Robert M.L. Mckay, Maitreyee Mukherjee Jan 2013

Rates And Controls Of Nitrification In A Large Oligotrophic Lake, Gaston E. Small, George S. Bullerjahn, Robert W. Sterner, Benjamin F.N. Beall, Sandra Brovold, Jacques C. Finlay, Robert M.L. Mckay, Maitreyee Mukherjee

Great Lakes Institute for Environmental Research Publications

Recent discoveries have altered prevailing paradigms concerning the conditions under which nitrification takes place and the organisms responsible for nitrification in aquatic ecosystems. In Lake Superior, nitrate (NO-3) concentrations have increased fivefold in the past century. Although previous evidence indicated that most NO-3 is generated by nitrification within the lake, important questions remain concerning the magnitude and controls of nitrification, and which microbial groups are primarily responsible for this process. We measured water-column nitrification rates in the western basin of Lake Superior during five research cruises from November 2009 to March 2011. Using in situ bottle incubations at 10 depths, …


What Causes The Decrease In Haematocrit During Egg Production?, T. D. Williams, W. O. Challenger, J. K. Christians, M. Evanson, O. Love, F. Vezina Jun 2004

What Causes The Decrease In Haematocrit During Egg Production?, T. D. Williams, W. O. Challenger, J. K. Christians, M. Evanson, O. Love, F. Vezina

Great Lakes Institute for Environmental Research Publications

1. Anaemia has been reported in wild animals, typically associated with traumatic events or ill health. However, female birds routinely become 'anaemic' during egg-laying; we sought to determine the causes of this reduction in haematocrit. 2. Haematocrit in female European Starlings (Sturnus vulgaris Linnaeus) decreased between pre-breeding and egg-laying in 3 out of 4 years (the decrease was marginally non-significant in the fourth year). This was independent of changes in ambient temperature altering the metabolic requirements for thermoregulation. 3. There was a positive relationship between haematocrit and plasma levels of the yolk precursor vitellogenin among egg-laying birds, supporting the hypothesis …