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Articles 1 - 11 of 11
Full-Text Articles in Life Sciences
Can We Predict Ectotherm Responses To Climate Change Using Thermal Performance Curves And Body Temperatures?, Brent J Sinclair, Katie E Marshall, Mary A Sewell, Danielle L Levesque, Christopher S Willett, Stine Slotsbo, Yunwei Dong, Christopher D G Harley, David J Marshall, Brian S Helmuth, Raymond B Huey
Can We Predict Ectotherm Responses To Climate Change Using Thermal Performance Curves And Body Temperatures?, Brent J Sinclair, Katie E Marshall, Mary A Sewell, Danielle L Levesque, Christopher S Willett, Stine Slotsbo, Yunwei Dong, Christopher D G Harley, David J Marshall, Brian S Helmuth, Raymond B Huey
Biology Publications
Thermal performance curves (TPCs), which quantify how an ectotherm's body temperature (Tb ) affects its performance or fitness, are often used in an attempt to predict organismal responses to climate change. Here, we examine the key - but often biologically unreasonable - assumptions underlying this approach; for example, that physiology and thermal regimes are invariant over ontogeny, space and time, and also that TPCs are independent of previously experienced Tb. We show how a critical consideration of these assumptions can lead to biologically useful hypotheses and experimental designs. For example, rather than assuming that TPCs are fixed during ontogeny, one …
Effects Of Acute And Chronic Interval Sprint Exercise Performed On A Manually Propelled Treadmill On Upper Limb Vascular Mechanics In Healthy Young Men., T Dylan Olver, Steph M Reid, Alan R Smith, Mair Zamir, Peter W R Lemon, M Harold Laughlin, J Kevin Shoemaker
Effects Of Acute And Chronic Interval Sprint Exercise Performed On A Manually Propelled Treadmill On Upper Limb Vascular Mechanics In Healthy Young Men., T Dylan Olver, Steph M Reid, Alan R Smith, Mair Zamir, Peter W R Lemon, M Harold Laughlin, J Kevin Shoemaker
Kinesiology Publications
Interval sprint exercise performed on a manually propelled treadmill, where the hands grip the handle bars, engages lower and upper limb skeletal muscle, but little is known regarding the effects of this exercise modality on the upper limb vasculature. We tested the hypotheses that an acute bout of sprint exercise and 6 weeks of training induces brachial artery (BA) and forearm vascular remodeling, favoring a more compliant system. Before and following a single bout of exercise as well as 6 weeks of training three types of vascular properties/methodologies were examined in healthy men: (1) stiffness of the entire upper limb …
Sex Allocation And The Emergence Of Helping In Cooperatively Breeding Species., Josh D Dunn, Teodora Vujicic, Geoff Wild
Sex Allocation And The Emergence Of Helping In Cooperatively Breeding Species., Josh D Dunn, Teodora Vujicic, Geoff Wild
Applied Mathematics Publications
In cooperative breeding systems individuals invest in the reproductive success of others. In this paper, we study the emergence of cooperative breeding systems in which reproductively active breeders receive investment from reproductively non-active helpers. Our goal is to understand how the division of an investment between male and female components of breeder fitness (i.e. the helper sex-allocation strategy) influences the emergence of cooperative breeding itself. Using mathematical models, we arrive at expressions for the inclusive-fitness advantage of helpful behaviour that generalize previous work. These expressions assume an ecologically stable environment, and that breeders make evolutionarily stable sex-allocation decisions. We find …
Molecular Effects Of Cancer-Associated Somatic Mutations On The Structural And Target Recognition Properties Of Keap1., Halema Khan, Ryan C Killoran, Anne Brickenden, Jingsong Fan, Daiwen Yang, Wing-Yiu Choy
Molecular Effects Of Cancer-Associated Somatic Mutations On The Structural And Target Recognition Properties Of Keap1., Halema Khan, Ryan C Killoran, Anne Brickenden, Jingsong Fan, Daiwen Yang, Wing-Yiu Choy
Biochemistry Publications
Kelch-like ECH-associated protein 1 (Keap1) plays an important regulatory role in the nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent oxidative stress response pathway. It functions as a repressor of Nrf2, a key transcription factor that initiates the expression of cytoprotective enzymes during oxidative stress to protect cells from damage caused by reactive oxygen species. Recent studies show that mutations of Keap1 can lead to aberrant activation of the antioxidant pathway, which is associated with different types of cancers. To gain a mechanistic understanding of the links between Keap1 mutations and cancer pathogenesis, we have investigated the molecular effects of a …
Cross-Tolerance And Cross-Talk In The Cold: Relating Low Temperatures To Desiccation And Immune Stress In Insects., Brent J Sinclair, Laura V Ferguson, Golnaz Salehipour-Shirazi, Heath A Macmillan
Cross-Tolerance And Cross-Talk In The Cold: Relating Low Temperatures To Desiccation And Immune Stress In Insects., Brent J Sinclair, Laura V Ferguson, Golnaz Salehipour-Shirazi, Heath A Macmillan
Biology Publications
Multiple stressors, both abiotic and biotic, often are experienced simultaneously by organisms in nature. Responses to these stressors may share signaling pathways ("cross-talk") or protective mechanisms ("cross-tolerance"). Temperate and polar insects that must survive the winter experience low temperatures accompanied by additional abiotic stressors, such as low availability of water. Cold and desiccation have many similar effects at a cellular level, and we present evidence that the cellular mechanisms that protect against cold stress also protect against desiccation, and that the responses to cold and dehydration likely evolved as cross-tolerance. By contrast, there are several lines of evidence suggesting that …
Identification Of Cold-Responsive Genes In A New Zealand Alpine Stick Insect Using Rna-Seq., Luke T Dunning, Alice B Dennis, Duckchul Park, Brent J Sinclair, Richard D Newcomb, Thomas R Buckley
Identification Of Cold-Responsive Genes In A New Zealand Alpine Stick Insect Using Rna-Seq., Luke T Dunning, Alice B Dennis, Duckchul Park, Brent J Sinclair, Richard D Newcomb, Thomas R Buckley
Biology Publications
The endemic New Zealand alpine stick insect Micrarchus nov. sp. 2 regularly experiences sub-zero temperatures in the wild. 454-based RNA-Seq was used to generate a de novo transcriptome and differentiate between treatments to investigate the genetic basis of cold tolerance. Non cold-treated individuals were compared to those exposed to 0°C for 1 h followed by a 1 h recovery period at 20°C. We aligned 607,410 Roche 454 reads, generating a transcriptome of 5235 contigs. Differential expression analysis ranked candidate cold responsive genes for qPCR validation by P-value. The top nine up-regulated candidates, together with eight a priori targets identified from …
A Model Of Intracellular Θ Phase Precession Dependent On Intrinsic Subthreshold Membrane Currents., L Stan Leung
A Model Of Intracellular Θ Phase Precession Dependent On Intrinsic Subthreshold Membrane Currents., L Stan Leung
Physiology and Pharmacology Publications
A hippocampal place cell fires at an increasingly earlier phase in relation to the extracellular theta rhythm as a rodent moves through the place field. The present report presents a compartment model of a CA1 pyramidal cell that explains the increase in amplitude and the phase precession of intracellular theta oscillations, with the assumption that the cell receives an asymmetric ramp depolarization (<10 >mV) in the place field and rhythmic inhibitory and/or excitatory synaptic driving. Intracellular subthreshold membrane potential oscillations (MPOs) increase in amplitude and frequency, and show phase precession within the place field. Theta phase precession and MPO power …
The Proton-Translocating A Subunit Of F0f1-Atp Synthase Is Allocated Asymmetrically To The Peripheral Stalk., Monika G Düser, Yumin Bi, Nawid Zarrabi, Stanley D Dunn, Michael Börsch
The Proton-Translocating A Subunit Of F0f1-Atp Synthase Is Allocated Asymmetrically To The Peripheral Stalk., Monika G Düser, Yumin Bi, Nawid Zarrabi, Stanley D Dunn, Michael Börsch
Biochemistry Publications
The position of the a subunit of the membrane-integral F0 sector of Escherichia coli ATP synthase was investigated by single molecule fluorescence resonance energy transfer studies utilizing a fusion of enhanced green fluorescent protein to the C terminus of the a subunit and fluorescent labels attached to specific positions of the epsilon or gamma subunits. Three fluorescence resonance energy transfer levels were observed during rotation driven by ATP hydrolysis corresponding to the three resting positions of the rotor subunits, gamma or epsilon, relative to the a subunit of the stator. Comparison of these positions of the rotor sites with those …
Domain Compliance And Elastic Power Transmission In Rotary F(O)F(1)-Atpase., Hendrik Sielaff, Henning Rennekamp, André Wächter, Hao Xie, Florian Hilbers, Katrin Feldbauer, Stanley D Dunn, Siegfried Engelbrecht, Wolfgang Junge
Domain Compliance And Elastic Power Transmission In Rotary F(O)F(1)-Atpase., Hendrik Sielaff, Henning Rennekamp, André Wächter, Hao Xie, Florian Hilbers, Katrin Feldbauer, Stanley D Dunn, Siegfried Engelbrecht, Wolfgang Junge
Biochemistry Publications
The 2 nanomotors of rotary ATP synthase, ionmotive F(O) and chemically active F(1), are mechanically coupled by a central rotor and an eccentric bearing. Both motors rotate, with 3 steps in F(1) and 10-15 in F(O). Simulation by statistical mechanics has revealed that an elastic power transmission is required for a high rate of coupled turnover. Here, we investigate the distribution in the F(O)F(1) structure of compliant and stiff domains. The compliance of certain domains was restricted by engineered disulfide bridges between rotor and stator, and the torsional stiffness (kappa) of unrestricted domains was determined by analyzing their thermal rotary …
Probing The Functional Tolerance Of The B Subunit Of Escherichia Coli Atp Synthase For Sequence Manipulation Through A Chimera Approach., Yumin Bi, Joel C Watts, Pamela Krauss Bamford, Lee-Ann K Briere, Stanley D Dunn
Probing The Functional Tolerance Of The B Subunit Of Escherichia Coli Atp Synthase For Sequence Manipulation Through A Chimera Approach., Yumin Bi, Joel C Watts, Pamela Krauss Bamford, Lee-Ann K Briere, Stanley D Dunn
Biochemistry Publications
A dimer of 156-residue b subunits forms the peripheral stator stalk of eubacterial ATP synthase. Dimerization is mediated by a sequence with an unusual 11-residue (hendecad) repeat pattern, implying a right-handed coiled coil structure. We investigated the potential for producing functional chimeras in the b subunit of Escherichia coli ATP synthase by replacing parts of its sequence with corresponding regions of the b subunits from other eubacteria, sequences from other polypeptides having similar hendecad patterns, and sequences forming left-handed coiled coils. Replacement of positions 55-110 with corresponding sequences from Bacillus subtilis and Thermotoga maritima b subunits resulted in fully functional …
The Stator Complex Of The A1a0-Atp Synthase--Structural Characterization Of The E And H Subunits., Erik Kish-Trier, Lee-Ann K Briere, Stanley D Dunn, Stephan Wilkens
The Stator Complex Of The A1a0-Atp Synthase--Structural Characterization Of The E And H Subunits., Erik Kish-Trier, Lee-Ann K Briere, Stanley D Dunn, Stephan Wilkens
Biochemistry Publications
Archaeal ATP synthase (A-ATPase) is the functional homolog to the ATP synthase found in bacteria, mitochondria and chloroplasts, but the enzyme is structurally more related to the proton-pumping vacuolar ATPase found in the endomembrane system of eukaryotes. We have cloned, overexpressed and characterized the stator-forming subunits E and H of the A-ATPase from the thermoacidophilic Archaeon, Thermoplasma acidophilum. Size exclusion chromatography, CD, matrix-assisted laser desorption ionization time-of-flight mass spectrometry and NMR spectroscopic experiments indicate that both polypeptides have a tendency to form dimers and higher oligomers in solution. However, when expressed together or reconstituted, the two individual polypeptides interact with …