Physical Sciences and Mathematics | Open Access Articles

Uncovering Adaptive Versus Acclimatized Alterations In Standard Metabolic Rate In Brown Bullhead (Ameiurus Nebulosus), Tood A. Leadley, Anne Mcleod, Timothy B. Johnson, Daniel D. Heath, Ken G. Drouillard

Great Lakes Institute for Environmental Research Publications

Standard metabolic rates (SMR) were measured in Brown Bullheads collected from two locations of the Detroit River, North America, representative of highly contaminated and uncontaminated areas. Measurements of SMR were completed within 10 d of fish collections (acute trials), for fish held in a common pond environment for 1 year (clearance trials) and for F1 generation fish raised in the pond environment (F1 study). SMRs were significantly higher (26%) in fish from the contaminated area during acute trials. Both populations showed large decreases in SMR (49 to 52 %) following clearance, however, differences between populations were still evident. There were …

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Α-Tocopherol Is Well Designed To Protect Polyunsaturated Phospholipids: Md Simulations, Xiaoling Leng, Jacob J. Kinnun, Drew Marquardt, Mikel Ghefli, Norbert Kučerka, John Katsaras, Jeffrey Atkinson, Thad A. Harroun, Scott E. Feller, Stephen R. Wassall

Chemistry and Biochemistry Publications

The presumptive function for alpha-tocopherol (αtoc) in membranes is to protect polyunsaturated lipids against oxidation. Although the chemistry of the process is well established, the role played by molecular structure that we address here with atomistic molecular-dynamics simulations remains controversial. The simulations were run in the constant particle NPT ensemble on hydrated lipid bilayers composed of SDPC (1-stearoyl-2-docosahexaenoylphosphatidylcholine, 18:0-22:6PC) and SOPC (1-stearoyl-2-oleoylphosphatidylcholine, 18:0-18:1PC) in the presence of 20 mol % αtoc at 37°C. SDPC with SA (stearic acid) for the sn-1 chain and DHA (docosahexaenoic acid) for the sn-2 chain is representative of polyunsaturated phospholipids, while SOPC with OA (oleic …

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A Comparison Of The Bioaccumulation Potential Of Mercury And Polychlorinated Biphenyls In Goldfish (Carassius Auratus), Jiajia Li, Ken G. Drouillard, Brian Braunfireun, Douglass G. Haffner

Great Lakes Institute for Environmental Research Publications

Both mercury (Hg) and polychlorinated biphenyls (PCBs) demonstrate food web biomagnification in aquatic ecosystems, yet their toxicokinetics have not been simultaneously contrasted within a common fish species. This study quantifies uptake and elimination rates of Hg and PCBs in goldfish. Fish were exposed to contaminated food containing PCBs and Hg to determine dietary chemical assimilation efficiencies (AEs) and elimination coefficients (k_tot). To test first-order kinetics, three exposure regimes were established by varying the proportion of contaminated fish incorporated into the food. Dietary AEs were 98 ± 10, 75 ± 12, and 40 ± 9% for MeHg, THg, and …

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Neutron Scattering At The Intersection Of Heart Health Science And Biophysics, Drew Marquardt, Richard J. Alsop, Maikel C. Rheinstädter, Thad A. Harroun

Chemistry and Biochemistry Publications

There is an urgent quest for improved heart health. Here, we review how neutron radiation can provide insight into the molecular basis of heart health. Lower cholesterol, a daily intake of aspirin and supplemental vitamin E are argued to all improve heart health. However, the mechanisms behind these common regimens, and others, are not entirely understood. It is not clear why a daily intake of aspirin can help some people with heart disease, and the benefits of vitamin E in the treatment of reperfusion injury have been heavily debated. The molecular impact of cholesterol in the body is still a …

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Asymmetric Lipid Membranes: Towards More Realistic Model Systems, Drew Marquardt, Barbara Geier, Georg Pabst

Chemistry and Biochemistry Publications

Despite the ubiquity of transbilayer asymmetry in natural cell membranes, the vast majority of existing research has utilized chemically well-defined symmetric liposomes, where the inner and outer bilayer leaflets have the same composition. Here, we review various aspects of asymmetry in nature and in model systems in anticipation for the next phase of model membrane studies.

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Pcb Food Web Dynamics Quantify Nutrient And Energy Flow In Aquatic Ecosystems, Anne M. Mcleod, Gord Paterson, Ken G. Drouillard, Douglas G. Haffner

Great Lakes Institute for Environmental Research Publications

Measuring in situ nutrient and energy flows in spatially and temporally complex aquatic ecosystems represents a major ecological challenge. Food web structure, energy and nutrient budgets are difficult to measure, and it is becoming more important to quantify both energy and nutrient flow to determine how food web processes and structure are being modified by multiple stressors. We propose that polychlorinated biphenyl (PCB) congeners represent an ideal tracer to quantify in situ energy and nutrient flow between trophic levels. Here, we demonstrate how an understanding of PCB congener bioaccumulation dynamics provides multiple direct measurements of energy and nutrient flow in …

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Substrate-Assisted And Enzymatic Pretransfer Editing Of Nonstandard Amino Acids By Methionyl-Trna Synthetase, Grant B. Fortowsky, Daniel J. Simard, Mohamed M. Aboelnga, James W. Gauld

Chemistry and Biochemistry Publications

Aminoacyl-tRNA synthetases (aaRSs) are cen- tral to a number of physiological processes, including protein biosynthesis. In particular, they activate and then transfer their corresponding amino acid to the cognate tRNA. This is achieved with a generally remarkably high fidelity by editing against incorrect standard and nonstandard amino acids. Using docking, molecular dynamics (MD), and hybrid quantum mechanical/molecular mechanics methods, we have inves- tigated mechanisms by which methionyl-tRNA synthetase (MetRS) may edit against the highly toxic, noncognate, amino acids homocysteine (Hcy) and its oxygen analogue, homo- serine (Hse). Substrate-assisted editing of Hcy-AMP in which its own phosphate acts as the mechanistic …

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Aspirin Inhibits Formation Of Cholesterol Rafts In Fluid Lipid Membranes, Richard J. Alsop, Laura Toppozini, Drew Marquardt, Norbert Kučerka, Thad A. Harroun, Maikel C. Rheinstädter

Chemistry and Biochemistry Publications

Aspirin and other non-steroidal anti-inflammatory drugs have a high affinity for phospholipid membranes, altering their structure and biophysical properties. Aspirin has been shown to partition into the lipid head groups, thereby increasing membrane fluidity. Cholesterol is another well known mediator of membrane fluidity, in turn increasing membrane stiffness. As well, cholesterol is believed to distribute unevenly within lipid membranes leading to the formation of lipid rafts or plaques. In many studies, aspirin has increased positive outcomes for patients with high cholesterol. We are interested if these effects may be, at least partially, the result of a non-specific interaction between aspirin …

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Hierarchical Analysis Of Genetic Structure In The Habitat-Specialist Eastern Sand Darter (Ammocrypta Pellucida), Robert Ginson, Ryan P. Walter, Nicholas E. Mandrak, Courtney L. Beneteau, Daniel D. Heath

Great Lakes Institute for Environmental Research Publications

Quantifying spatial genetic structure can reveal the relative influences of contemporary and historic factors underlying localized and regional patterns of genetic diversity and gene flow - important considerations for the development of effective conservation efforts. Using 10 polymorphic microsatellite loci, we characterize genetic variation among populations across the range of the Eastern Sand Darter (Ammocrypta pellucida), a small riverine percid that is highly dependent on sandy substrate microhabitats. We tested for fine scale, regional, and historic patterns of genetic structure. As expected, significant differentiation was detected among rivers within drainages and among drainages. At finer scales, an unexpected lack of …

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Benefits Of Turbid River Plume Habitat For Lake Erie Yellow Perch (Perca Flavescens) Recruitment Determined By Juvenile To Larval Genotype Assignment, Lucia B. Carreon-Martinez, Ryan P. Walter, Timothy B. Johnson, Stuart A. Ludsin, Daniel D. Heath

Great Lakes Institute for Environmental Research Publications

Nutrient-rich, turbid river plumes that are common to large lakes and coastal marine ecosystems have been hypothesized to benefit survival of fish during early life stages by increasing food availability and (or) reducing vulnerability to visual predators. However, evidence that river plumes truly benefit the recruitment process remains meager for both freshwater and marine fishes. Here, we use genotype assignment between juvenile and larval yellow perch (Perca flavescens) from western Lake Erie to estimate and compare recruitment to the age-0 juvenile stage for larvae residing inside the highly turbid, south-shore Maumee River plume versus those occupying the less turbid, more …

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Particle Backtracking Improves Breeding Subpopulation Discrimination And Natal-Source Identification In Mixed Populations, Michael E. Fraker, Eric J. Anderson, Reed M. Brodnik, Lucia Carreon-Martinez, Kristen M. Devanna, Brian J. Fryer, Daniel D. Heath, Julie M. Reichert, Stuart A. Ludsin

Great Lakes Institute for Environmental Research Publications

We provide a novel method to improve the use of natural tagging approaches for subpopulation discrimination and source-origin identification in aquatic and terrestrial animals with a passive dispersive phase. Our method integrates observed site-referenced biological information on individuals in mixed populations with a particle-tracking model to retrace likely dispersal histories prior to capture (i.e., particle backtracking). To illustrate and test our approach, we focus on western Lake Erie's yellow perch (Perca flavescens) population during 2006-2007, using microsatellite DNA and otolith microchemistry from larvae and juveniles as natural tags. Particle backtracking showed that not all larvae collected near a presumed hatching …

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Effect Of Cod: So42- Ratio, Hrt And Linoleic Acid Concentration On Mesophilic Sulfate Reduction: Reactor Performance And Microbial Population Dynamics, Chungman Moon, Rajesh Singh, Sathyanarayan S. Veeravalli, Saravanan R. Shanmugam, Subba Rao Chaganti, Jerald A. Lalman, Daniel D. Heath

Great Lakes Institute for Environmental Research Publications

Biological sulfate (SO42-) reduction was examined in anaerobic sequential batch reactors (ASBRs) operated under different hydraulic retention times (HRTs) ranging from 12 to 36 h and COD (Chemical Oxygen Demand)/SO42- ratios of 2.4, 1.6 and 0.8. Competition between SO42- reducing bacteria (SRBs), methane producing archaea (MPAs) and homoacetogens (HACs) was examined in controls and cultures treated with linoleic acid (LA). The ASBR performance was influenced by the COD/SO42- ratio in control cultures with a SO42- reduction of 87% at a COD/SO42- ratio of 0.8. At a 12 h HRT, in both control and LA treated cultures, greater than 75% SO42- …

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The Effects Of Inbreeding On Sperm Quality Traits In Captive-Bred Lake Trout, Salvelinus Namaycush (Walbaum, 1972), K. Johnson, Ian A.E. Butts, J. L. Smith, C. C. Wilson, Trevor E. Pitcher

Great Lakes Institute for Environmental Research Publications

The effects of inbreeding in both captive and wild-caught species and populations have been reported to affect a wide variety of life history traits. Recently, the effects of inbreeding on reproductive traits such as sperm quality have become a subject of particular interest for conservation biology, evolutionary ecology, and management of captive populations. This study investigated the effects of inbreeding on sperm quality in a captive population of experimentally inbred and outbred lake trout, Salvelinus namaycush. It was found for moderately to highly inbred males (males with half-sib and full-sib parents, respectively), that sperm quality traits (velocity, motility, linearity, longevity, …

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Full-Text Articles in Physical Sciences and Mathematics

Uncovering Adaptive Versus Acclimatized Alterations In Standard Metabolic Rate In Brown Bullhead (Ameiurus Nebulosus), Tood A. Leadley, Anne Mcleod, Timothy B. Johnson, Daniel D. Heath, Ken G. Drouillard

Great Lakes Institute for Environmental Research Publications

Α-Tocopherol Is Well Designed To Protect Polyunsaturated Phospholipids: Md Simulations, Xiaoling Leng, Jacob J. Kinnun, Drew Marquardt, Mikel Ghefli, Norbert Kučerka, John Katsaras, Jeffrey Atkinson, Thad A. Harroun, Scott E. Feller, Stephen R. Wassall

Chemistry and Biochemistry Publications

A Comparison Of The Bioaccumulation Potential Of Mercury And Polychlorinated Biphenyls In Goldfish (Carassius Auratus), Jiajia Li, Ken G. Drouillard, Brian Braunfireun, Douglass G. Haffner

Great Lakes Institute for Environmental Research Publications

Neutron Scattering At The Intersection Of Heart Health Science And Biophysics, Drew Marquardt, Richard J. Alsop, Maikel C. Rheinstädter, Thad A. Harroun

Chemistry and Biochemistry Publications

Asymmetric Lipid Membranes: Towards More Realistic Model Systems, Drew Marquardt, Barbara Geier, Georg Pabst

Chemistry and Biochemistry Publications

Pcb Food Web Dynamics Quantify Nutrient And Energy Flow In Aquatic Ecosystems, Anne M. Mcleod, Gord Paterson, Ken G. Drouillard, Douglas G. Haffner

Great Lakes Institute for Environmental Research Publications

Substrate-Assisted And Enzymatic Pretransfer Editing Of Nonstandard Amino Acids By Methionyl-Trna Synthetase, Grant B. Fortowsky, Daniel J. Simard, Mohamed M. Aboelnga, James W. Gauld

Chemistry and Biochemistry Publications

Aspirin Inhibits Formation Of Cholesterol Rafts In Fluid Lipid Membranes, Richard J. Alsop, Laura Toppozini, Drew Marquardt, Norbert Kučerka, Thad A. Harroun, Maikel C. Rheinstädter

Chemistry and Biochemistry Publications

Hierarchical Analysis Of Genetic Structure In The Habitat-Specialist Eastern Sand Darter (Ammocrypta Pellucida), Robert Ginson, Ryan P. Walter, Nicholas E. Mandrak, Courtney L. Beneteau, Daniel D. Heath

Great Lakes Institute for Environmental Research Publications

Benefits Of Turbid River Plume Habitat For Lake Erie Yellow Perch (Perca Flavescens) Recruitment Determined By Juvenile To Larval Genotype Assignment, Lucia B. Carreon-Martinez, Ryan P. Walter, Timothy B. Johnson, Stuart A. Ludsin, Daniel D. Heath

Great Lakes Institute for Environmental Research Publications

Particle Backtracking Improves Breeding Subpopulation Discrimination And Natal-Source Identification In Mixed Populations, Michael E. Fraker, Eric J. Anderson, Reed M. Brodnik, Lucia Carreon-Martinez, Kristen M. Devanna, Brian J. Fryer, Daniel D. Heath, Julie M. Reichert, Stuart A. Ludsin

Great Lakes Institute for Environmental Research Publications

Effect Of Cod: So42- Ratio, Hrt And Linoleic Acid Concentration On Mesophilic Sulfate Reduction: Reactor Performance And Microbial Population Dynamics, Chungman Moon, Rajesh Singh, Sathyanarayan S. Veeravalli, Saravanan R. Shanmugam, Subba Rao Chaganti, Jerald A. Lalman, Daniel D. Heath

Great Lakes Institute for Environmental Research Publications

The Effects Of Inbreeding On Sperm Quality Traits In Captive-Bred Lake Trout, Salvelinus Namaycush (Walbaum, 1972), K. Johnson, Ian A.E. Butts, J. L. Smith, C. C. Wilson, Trevor E. Pitcher

Great Lakes Institute for Environmental Research Publications