Research Topics
Species | Richard BertramSummaryAffiliation: Florida State University Country: USA Publications
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Publications
Role for G protein Gbetagamma isoform specificity in synaptic signal processing: a computational studyRichard Bertram
Department of Mathematics and Kasha Laboratory of Biophysics, Florida State University, Tallahassee, Florida 32306, USA
J Neurophysiol 87:2612-23. 2002..This allows for great synapse-to-synapse variability in the distinction between signal and noise...- A mathematical model for the actions of activin, inhibin, and follistatin on pituitary gonadotrophsRichard Bertram
Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, FL 32306 4510, USA
Bull Math Biol 70:2211-28. 2008..We conclude that the actions of activin, inhibin, and follistatin are consistent with LH/FSH secretion patterns, and likely complement other factors in the production of the characteristic secretion patterns in female rats... - Filtering of calcium transients by the endoplasmic reticulum in pancreatic beta-cellsRichard Bertram
Department of Mathematics and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
Biophys J 87:3775-85. 2004..Finally, we show that a three-compartment model that includes a subspace compartment between the ER and the plasma membrane provides the best agreement with the experimental Ca2+ data... - Calcium and glycolysis mediate multiple bursting modes in pancreatic isletsRichard Bertram
Department of Mathematics and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
Biophys J 87:3074-87. 2004..We provide experimental support for this model prediction. Overall, the model can account for a diversity of islet behaviors described in the literature over the past 20 years... - Endothelin action on pituitary lactotrophs: one receptor, many GTP-binding proteinsRichard Bertram
Department of Mathematics, Florida State University, Tallahassee, FL 32306, USA
Sci STKE 2006:er2. 2006..The initial effect is stimulatory, followed later by inhibition that persists long after the agonist has been removed. Recent research has uncovered several G protein pathways that mediate these effects... - Electrical bursting, calcium oscillations, and synchronization of pancreatic isletsRichard Bertram
Department of Mathematics, Florida State University, Tallahassee, FL 32306, USA
Adv Exp Med Biol 654:261-79. 2010..Disturbance of oscillations, either at the level of the individual islet or at the level of islet synchronization, is detrimental and can play a major role in type 2 diabetes... - A phantom bursting mechanism for episodic burstingRichard Bertram
Department of Mathematics, Florida State University, Tallahassee, FL 32306 4510, USA
Bull Math Biol 70:1979-93. 2008..This mechanism could account for episodic bursting produced in endocrine cells or neurons, such as pancreatic islets or gonadotropin releasing neurons of the hypothalamus... - A mathematical study of the differential effects of two SERCA isoforms on Ca2+ oscillations in pancreatic isletsRichard Bertram
Department of Mathematics, Florida State University, Tallahassee, FL 32306, USA
Bull Math Biol 70:1251-71. 2008..Unlike SERCA3 inhibition, we demonstrate that SERCA2b inhibition has no long-term effect on cytosolic Ca2+ oscillations unless a store-operated current is activated... - A minimal model for G protein-mediated synaptic facilitation and depressionRichard Bertram
Department of Mathematics, Florida State University, Tallahassee, Florida 32306, USA
J Neurophysiol 90:1643-53. 2003..Finally, we demonstrate that relief of G protein inhibition can contribute to paired-pulse facilitation... - A simplified model for mitochondrial ATP productionRichard Bertram
Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
J Theor Biol 243:575-86. 2006.... - Interaction of glycolysis and mitochondrial respiration in metabolic oscillations of pancreatic isletsRichard Bertram
Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
Biophys J 92:1544-55. 2007..Finally, we use the model to address the recent finding that the activity of islets from some mice is uniformly fast, whereas that from islets of other mice is slow. We propose a mechanism for this dichotomy... - Endothelin action on pituitary lactotrophs: one receptor, many GTP-binding proteinsRichard Bertram
Department of Mathematics, Florida State University, Tallahassee, FL 32306, USA
Sci STKE 2006:pe4. 2006..The initial effect is stimulatory, followed later by inhibition that persists long after the agonist has been removed. Recent research has uncovered several G protein pathways that mediate these effects... - Systemic oxytocin induces a prolactin secretory rhythm via the pelvic nerve in ovariectomized ratsCleyde V Helena
Departments of Biological Science, Biomedical Research Facility, Florida State University, Tallahassee, FL, USA
Am J Physiol Regul Integr Comp Physiol 301:R676-81. 2011..In fact, OT injection failed to induce a PRL secretory rhythm in pelvic-neurectomized animals, suggesting that the integrity of the pelvic nerve is necessary for the systemic OT induction of the PRL secretory rhythm in OVX rats... - A mathematical model for the mating-induced prolactin rhythm of female ratsRichard Bertram
Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
Am J Physiol Endocrinol Metab 290:E573-82. 2006..Finally, we consider potential targets for a rhythm-terminating factor and make predictions that may be used to determine which mechanism is operational in terminating the OT- or mating-induced PRL rhythm... - The rhythmic secretion of mating-induced prolactin secretion is controlled by prolactin acting centrallyCleyde V Helena
Department of Biological Science, Florida State University, Tallahassee, Florida 32306 4340, USA
Endocrinology 150:3245-51. 2009..These results demonstrate that PRL acts centrally to induce the PRL rhythm and that PRL in the brain is essential for the maintenance but not for the initiation of the CS-induced rhythmic PRL surges... - Oxytocin action at the lactotroph is required for prolactin surges in cervically stimulated ovariectomized ratsDe nise T McKee
Department of Biological Science, Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA
Endocrinology 148:4649-57. 2007.... - Prolactin secretory rhythm of mated rats induced by a single injection of oxytocinMarcel Egli
Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
Am J Physiol Endocrinol Metab 290:E566-72. 2006..Mathematical modeling was used to illustrate the proposed network function. The experimental results further suggest an additional feedback mechanism in which certain hypothalamic OTergic neurons are influenced by PRL... - Correlation analysis a tool for comparing relaxation-type models to experimental dataMaurizio Tomaiuolo
Department of Biological Science and Program in Neuroscience, Florida State University, Tallahassee, Florida, USA
Methods Enzymol 467:1-22. 2009..Otherwise, the model must be corrected. While this tool is only one test of many required to validate a mathematical model, it is easy to implement and is noninvasive... - Low dose of dopamine may stimulate prolactin secretion by increasing fast potassium currentsJoel Tabak
Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
J Comput Neurosci 22:211-22. 2007..Thus, the stimulatory effects of DA could be mediated by a fast K+ conductance which converts tonically spiking cells to bursters. In addition, the study illustrates that.. - Metabolic and electrical oscillations: partners in controlling pulsatile insulin secretionRichard Bertram
Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
Am J Physiol Endocrinol Metab 293:E890-900. 2007..The model, however, still lacks direct confirmation and raises new issues. In this article, we highlight both the successes of the model and the challenges that it poses for the field... - A-type K(+) current can act as a trigger for bursting in the absence of a slow variableNatalia Toporikova
Department of Mathematics, Florida State University, Tallahassee, FL 32306, USA
Neural Comput 20:436-51. 2008..To our knowledge, this is the first example of a physiologically based, single-compartmental model of bursting with no slow subsystem... - From plateau to pseudo-plateau bursting: making the transitionWondimu Teka
Department of Mathematics, Florida State University, Tallahassee, USA
Bull Math Biol 73:1292-311. 2011..This suggests that the design principles for bursting in endocrine cells are just quantitative variations of those for bursting in neurons... - Variations in the response of pituitary lactotrophs to oxytocin during the rat estrous cycleJoel Tabak
Department of Biological Science, Florida State University, BRF 206, Tallahassee, Florida 32306, USA
Endocrinology 151:1806-13. 2010.... - Mathematical aspects of protein structure determination with NMR orientational restraintsJ R Quine
Department of Mathematics, Florida State University, Tallahassee, FL 32306, USA
Bull Math Biol 66:1705-30. 2004..These two processes, initial model building followed by refinement, are the two crucial steps between data collection and the final atomic model... - Synchronization of mouse islets of Langerhans by glucose waveformsXinyu Zhang
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, 32306, USA
Am J Physiol Endocrinol Metab 301:E742-7. 2011.... - Quantifying the relative contributions of divisive and subtractive feedback to rhythm generationJoel Tabak
Department of Biological Sciences, Florida State University, Tallahassee, Florida, USA
PLoS Comput Biol 7:e1001124. 2011..However, only the subtractive process plays a major role in setting the duration of the silent phase. This computational method can be used to analyze the role of negative feedback processes in a wide range of biological rhythms... - Rhythmic secretion of prolactin in rats: action of oxytocin coordinated by vasoactive intestinal polypeptide of suprachiasmatic nucleus originMarcel Egli
Department of Biological Sciecne, Florida State University, Tallahassee, Florida 32306 4340, USA
Endocrinology 145:3386-94. 2004..This hypothesis is illustrated with a mathematical model... - A calcium-based phantom bursting model for pancreatic isletsRichard Bertram
Department of Mathematics and Kasha Laboratory of Biophysics, Florida State University, Tallahassee, Florida 32306, USA
Bull Math Biol 66:1313-44. 2004..Although it is not presently a complete model of all beta-cell properties, it demonstrates the design principles that we anticipate will underlie future progress in beta-cell modeling... - Complex bursting in pancreatic islets: a potential glycolytic mechanismKeola Wierschem
Department of Mathematics, Florida State University, Tallahassee, FL 32306, USA
J Theor Biol 228:513-21. 2004..We show that the combined model can reproduce several complex bursting patterns from mouse islets published in the literature, and we illustrate how these complex oscillations are produced through the use of a fast/slow analysis... - Slow variable dominance and phase resetting in phantom burstingMargaret Watts
Department of Mathematics, Florida State University, Tallahassee, FL, USA
J Theor Biol 276:218-28. 2011..Finally, we demonstrate two mechanisms by which phase-independent resetting of a burst can be achieved, as has been shown to occur in the electrical activity of pancreatic islets... - Dual pre-motor contribution to songbird syllable variationJohn A Thompson
Program in Neuroscience and Department of Psychology, Florida State University, Tallahassee, Florida 32306 4301, USA
J Neurosci 31:322-30. 2011.... - Enzyme isoforms may increase phenotypic robustnessMaurizio Tomaiuolo
Department of Biological Science, Florida State University, Tallahassee, Florida 32306, USA
Evolution 62:2884-93. 2008..Thus, we show that controlling isoform proportion can be a powerful mechanism for reducing the effects of variations in the values of system parameters, increasing system robustness... - Mechanism for the universal pattern of activity in developing neuronal networksJoel Tabak
Dept of Biological Science, BRF 206, Florida State Univ, Tallahassee, FL 32306, USA
J Neurophysiol 103:2208-21. 2010..This work further shows that networks with widely different architectures, different cell types, and different functions all operate according to the same general mechanism early in their development... - Microfluidic system for generation of sinusoidal glucose waveforms for entrainment of islets of LangerhansXinyu Zhang
Department of Chemistry and Biochemistry and Program in Molecular Biophysics, Florida State University, Tallahassee, Florida 32306, USA
Anal Chem 82:6704-11. 2010..The system should be applicable to a wide range of cell types to aid understanding cellular responses to dynamically changing stimuli... - Fast-Activating Voltage- and Calcium-Dependent Potassium (BK) Conductance Promotes Bursting in Pituitary Cells: A Dynamic Clamp StudyJoel Tabak
Department of Biological Science and Department of Mathematics and Program in Neuroscience, Florida State University, Tallahassee, Florida 32306, and Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211
J Neurosci 31:16855-63. 2011.... - Mathematical modeling demonstrates how multiple slow processes can provide adjustable control of islet burstingMargaret Watts
Department of Mathematics, Florida State University, Tallahassee, FL, USA
Islets 3:320-6. 2011.... - Using phase relations to identify potential mechanisms for metabolic oscillations in isolated ?-cell mitochondriaRichard Bertram
Department of Mathematics and Programs in Molecular Biophysics and Neuroscience, Florida State University, Tallahassee, Florida, USA
Islets 1:87-94. 2009..This analysis shows that the observed phase relation between citrate and NAD(P) places strict limits on the potential mechanism for the metabolic oscillations in isolated mitochondria that were observed by MacDonald and co-workers... - A statistical method for quantifying songbird phonology and syntaxWei Wu
Department of Statistics, Florida State University, Tallahassee, FL 32306 4330, USA
J Neurosci Methods 174:147-54. 2008..We then apply the standard information-theoretic quantity K-L distance to measure dissimilarity in phonology across days of singing. A variant of this procedure can also be used to analyze differences in syllable syntax... - Atomic refinement with correlated solid-state NMR restraintsRichard Bertram
Department of Mathematics, Florida State University, Tallahassee, FL 32306 4510, USA
J Magn Reson 163:300-9. 2003..The software used to correlate dipolar coupling and chemical shift data and to set up energy functions and their derivatives for refinement, CNS-SS02, is available at our web site... - Auditory-dependent vocal recovery in adult male zebra finches is facilitated by lesion of a forebrain pathway that includes the basal gangliaJohn A Thompson
Program in Neuroscience, Florida State University, Tallahassee, Florida 32306 1270, USA
J Neurosci 27:12308-20. 2007..In part, auditory feedback may restore song by strengthening the VMP component of synaptic input to RA relative to the AFP component... - Simulated-annealing real-space refinement as a tool in model buildingAndrei Korostelev
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4380, USA
Acta Crystallogr D Biol Crystallogr 58:761-7. 2002.... - An improved hydrogen bond potential: impact on medium resolution protein structuresFelcy Fabiola
Kasha Laboratory of Biophysics, Florida State University, Tallahassee, Florida 32306-4380, USA
Protein Sci 11:1415-23. 2002..These findings highlight common misconceptions about hydrogen bonding in proteins, and provide explanations for why the explicit hydrogen bonding terms of some popular force field sets are often best switched off... - Intra- and inter-islet synchronization of metabolically driven insulin secretionMorten Gram Pedersen
Department of Mathematics, Technical University of Denmark, Kgs. Lyngby, Denmark
Biophys J 89:107-19. 2005..Thus, we demonstrate how intra-islet and inter-islet synchronization of insulin oscillations may be achieved... - The Ca2+ dynamics of isolated mouse beta-cells and islets: implications for mathematical modelsMin Zhang
Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond 23298, USA
Biophys J 84:2852-70. 2003..These results support our recent model and point to the important role of beta-cell electrical events in controlling [Ca(2+)](i) over diverse time scales in islets... - Glucose modulates [Ca2+]i oscillations in pancreatic islets via ionic and glycolytic mechanismsCraig S Nunemaker
Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
Biophys J 91:2082-96. 2006.... - Backbone structure of the amantadine-blocked trans-membrane domain M2 proton channel from Influenza A virusJun Hu
The National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
Biophys J 92:4335-43. 2007..In addition, spectra are shown of the amantadine-resistant mutant, S31N, in the presence and absence of amantadine... - Diffusion of calcium and metabolites in pancreatic islets: killing oscillations with a pitchforkKrasimira Tsaneva-Atanasova
Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
Biophys J 90:3434-46. 2006..We suggest that these modes are generic features of square-wave bursters and relaxation oscillators coupled through either the activation or recovery variable... - Residual bound Ca2+ can account for the effects of Ca2+ buffers on synaptic facilitationVictor Matveev
New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA
J Neurophysiol 96:3389-97. 2006..We conclude that Ca(2+) binding processes with slow unbinding times (tens to hundreds of milliseconds) constitute a viable mechanism of synaptic facilitation at some synapses and discuss the experimental evidence for such a mechanism... - Individual mice can be distinguished by the period of their islet calcium oscillations: is there an intrinsic islet period that is imprinted in vivo?Craig S Nunemaker
Department of Pharmacology and Toxicology, Virginia Commonwealth University, P.O. Box 980524, Richmond, Virginia 23298, USA
Diabetes 54:3517-22. 2005..We propose that individual mice have characteristic oscillatory [Ca2+]i patterns, which are imprinted in vivo through an unknown mechanism...
Research Grants
- CRCNS:Comput./Exp.Study:Hypothal.-Pituitary InteractionRichard Bertram; Fiscal Year: 2007..It will then lead to studies of effects of drugs of abuse on brain-pituitary function. ..