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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

A Role For The Forebrain In Mediating Time-Of-Day Differences In Glucocorticoid Counterregulatory Responses To Hypoglycemia In Rats, Lori M. Gorton, Arshad M. Khan, Maryann Bohland, Graciela Sanchez-Watts, Casey M. Donovan, Alan G. Watts Sep 2007

A Role For The Forebrain In Mediating Time-Of-Day Differences In Glucocorticoid Counterregulatory Responses To Hypoglycemia In Rats, Lori M. Gorton, Arshad M. Khan, Maryann Bohland, Graciela Sanchez-Watts, Casey M. Donovan, Alan G. Watts

Arshad M. Khan, Ph.D.

No abstract provided.


Phenylalanyl-Trna Synthetase Editing Defects Result In Efficient Mistranslation Of Phenylalanine Codons As Tyrosine, Jiqiang Ling, Srujana S. Yadavalli, Michael Ibba Sep 2007

Phenylalanyl-Trna Synthetase Editing Defects Result In Efficient Mistranslation Of Phenylalanine Codons As Tyrosine, Jiqiang Ling, Srujana S. Yadavalli, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Translational quality control is monitored at several steps, including substrate selection by aminoacyl-tRNA synthetases (aaRSs), and discrimination of aminoacyl-tRNAs by elongation factor Tu (EF-Tu) and the ribosome. Phenylalanyl-tRNA synthetase (PheRS) misactivates Tyr but is able to correct the mistake using a proofreading activity named editing. Previously we found that overproduction of editing-defective PheRS resulted in Tyr incorporation at Phe-encoded positions in vivo , although the misreading efficiency could not be estimated. This raised the question as to whether or not EF-Tu and the ribosome provide further proofreading mechanisms to prevent mistranslation of Phe codons by Tyr. Here we show that, …


An Aminoacyl-Trna Synthetase: Elongation Factor Complex For Substrate Channeling In Archaeal Translation, Corinne D. Hausmann, Mette Praetorius-Ibba, Michael Ibba Sep 2007

An Aminoacyl-Trna Synthetase: Elongation Factor Complex For Substrate Channeling In Archaeal Translation, Corinne D. Hausmann, Mette Praetorius-Ibba, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Translation requires the specific attachment of amino acids to tRNAs by aminoacyl-tRNA synthetases (aaRSs) and the subsequent delivery of aminoacyl-tRNAs to the ribosome by elongation factor 1 alpha (EF-1α). Interactions between EF-1α and various aaRSs have been described in eukaryotes, but the role of these complexes remains unclear. To investigate possible interactions between EF-1α and other cellular components, a yeast two-hybrid screen was performed for the archaeon Methanothermobacter thermautotrophicus. EF-1α was found to form a stable complex with leucyl-tRNA synthetase (LeuRS; KD = 0.7 μ M). Complex formation had little effect on EF-1α activity, but increased the kcat …


Catecholaminergic Control Of Mitogen-Activated Protein Kinase Signaling In Paraventricular Neuroendocrine Neurons In Vivo And In Vitro: A Proposed Role During Glycemic Challenges, Arshad M. Khan, Todd A. Ponzio, Graciela Sanchez-Watts, B. Glenn Stanley, Glenn I. Hatton, Alan G. Watts Jul 2007

Catecholaminergic Control Of Mitogen-Activated Protein Kinase Signaling In Paraventricular Neuroendocrine Neurons In Vivo And In Vitro: A Proposed Role During Glycemic Challenges, Arshad M. Khan, Todd A. Ponzio, Graciela Sanchez-Watts, B. Glenn Stanley, Glenn I. Hatton, Alan G. Watts

Arshad M. Khan, Ph.D.

No abstract provided.


Inhibition Of Nitric Oxide And Soluble Guanylyl Cyclase Signaling Affects Olfactory Neuron Activity In The Moth, Manduca Sexta, Caroline H. Wilson, Thomas A. Christensen, Alan J. Nighorn Jun 2007

Inhibition Of Nitric Oxide And Soluble Guanylyl Cyclase Signaling Affects Olfactory Neuron Activity In The Moth, Manduca Sexta, Caroline H. Wilson, Thomas A. Christensen, Alan J. Nighorn

Health Sciences and Kinesiology Faculty Articles

Nitric oxide is emerging as an important modulator of many physiological processes including olfaction, yet the function of this gas in the processing of olfactory information remains poorly understood. In the antennal lobe of the moth, Manduca sexta, nitric oxide is produced in response to odor stimulation, and many interneurons express soluble guanylyl cyclase, a well-characterized nitric oxide target. We used intracellular recording and staining coupled with pharmacological manipulation of nitric oxide and soluble guanylyl cyclase to test the hypothesis that nitric oxide modulates odor responsiveness in olfactory interneurons through soluble guanylyl cyclase-dependent pathways. Nitric oxide synthase inhibition resulted …


Direct Comparison Of Feature Tracking And Autocorrelation For Velocity Estimation, Gregory R. Bashford, Derek J. Robinson Apr 2007

Direct Comparison Of Feature Tracking And Autocorrelation For Velocity Estimation, Gregory R. Bashford, Derek J. Robinson

Biomedical Imaging and Biosignal Analysis Laboratory

Feature tracking is an algorithm for estimating tissue motion and blood flow using pulse-echo ultrasound. It was proposed as a computationally simpler alternative to other techniques such as autocorrelation and time-domain cross correlation. The advantage of feature tracking is that it selectively extracts easily identifiable parts of the speckle signal (e.g., the local maxima), reducing the amount of information being processed. Studies on feature tracking to date have used stationary, specklegenerating targets to simulate blood flow. Also, feature tracking has not been compared with accepted commercial methods. This study directly compares feature tracking performance with the complex autocorrelation method, which …


A Proposal For Robust Temperature Compensation Of Circadian Rhythms, Christian I. Hong, Emery D. Conrad, John J. Tyson Jan 2007

A Proposal For Robust Temperature Compensation Of Circadian Rhythms, Christian I. Hong, Emery D. Conrad, John J. Tyson

Dartmouth Scholarship

The internal circadian rhythms of cells and organisms coordinate their physiological properties to the prevailing 24-h cycle of light and dark on earth. The mechanisms generating circadian rhythms have four defining characteristics: they oscillate endogenously with period close to 24 h, entrain to external signals, suffer phase shifts by aberrant pulses of light or temperature, and compensate for changes in temperature over a range of 10°C or more. Most theoretical descriptions of circadian rhythms propose that the underlying mechanism generates a stable limit cycle oscillation (in constant darkness or dim light), because limit cycles quite naturally possess the first three …


Vglut And Gad65 Expression In Physiologically Characterized Ia Afferents, Ivonne Nkoli Ukpabi Jan 2007

Vglut And Gad65 Expression In Physiologically Characterized Ia Afferents, Ivonne Nkoli Ukpabi

Browse all Theses and Dissertations

Peripheral nerve injury is known to induce several changes in the physiology and morphology of the injured afferent. These changes include hyperexcitability, decreased dorsal root potentials (DRP), loss of synaptic vesicles as well as loss of the vesicular glutamate transporter, VGLUT1. While many of the changes caused by peripheral injury revert with regeneration, others appear to be permanent. The loss of the stretch reflex for example is a puzzling outcome of recovery after peripheral nerve transection and regeneration, especially given that the electrical counterpart of the stretch reflex (the H-reflex) recovers after regeneration. We hypothesized that stretch induced transmission is …