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Physiology

2015

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Articles 1 - 29 of 29

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

Alternative Use Of Dna Binding Domains By The Neurospora White Collar Complex Dictates Circadian Regulation And Light Responses, Bin Wang, Xiaoying Zhou, Jennifer J. Loros, Jay C. Dunlap Dec 2015

Alternative Use Of Dna Binding Domains By The Neurospora White Collar Complex Dictates Circadian Regulation And Light Responses, Bin Wang, Xiaoying Zhou, Jennifer J. Loros, Jay C. Dunlap

Open Dartmouth: Faculty Open Access Scholarship

In the Neurospora circadian system, the White Collar complex (WCC) of WC-1 and WC-2 drives transcription of the circadian pacemaker gene frequency (frq), whose gene product, FRQ, as a part of the FRQ-FRH complex (FFC), inhibits its own expression. The WCC is also the principal Neurospora photoreceptor; WCC-mediated light induction of frq resets the clock, and all acute light induction is triggered by WCC binding to promoters of light-induced genes. However, not all acutely light-induced genes are also clock regulated, and conversely, not all clock-regulated direct targets of WCC are light induced; the structural determinants governing the shift from WCC ...


Endothelial Protein Kinase Map4k4 Promotes Vascular Inflammation And Atherosclerosis, Rachel J. Roth Flach, Athanasia Skoura, Anouch Matevossian, Laura V. Danai, Wei Zheng, Christian Cortes, Samit K. Bhattacharya, Myriam Aouadi, G. Nana Hagan, Joseph Yawe, Pranitha Vangala, Lorena Garcia Menendez, Marcus P. Cooper, Timothy P. Fitzgibbons, Leonard Buckbinder, Michael P. Czech Dec 2015

Endothelial Protein Kinase Map4k4 Promotes Vascular Inflammation And Atherosclerosis, Rachel J. Roth Flach, Athanasia Skoura, Anouch Matevossian, Laura V. Danai, Wei Zheng, Christian Cortes, Samit K. Bhattacharya, Myriam Aouadi, G. Nana Hagan, Joseph Yawe, Pranitha Vangala, Lorena Garcia Menendez, Marcus P. Cooper, Timothy P. Fitzgibbons, Leonard Buckbinder, Michael P. Czech

Program in Molecular Medicine Publications and Presentations

Signalling pathways that control endothelial cell (EC) permeability, leukocyte adhesion and inflammation are pivotal for atherosclerosis initiation and progression. Here we demonstrate that the Sterile-20-like mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4), which has been implicated in inflammation, is abundantly expressed in ECs and in atherosclerotic plaques from mice and humans. On the basis of endothelial-specific MAP4K4 gene silencing and gene ablation experiments in Apoe(-/-) mice, we show that MAP4K4 in ECs markedly promotes Western diet-induced aortic macrophage accumulation and atherosclerotic plaque development. Treatment of Apoe(-/-) and Ldlr(-/-) mice with a selective small-molecule MAP4K4 inhibitor also markedly reduces atherosclerotic ...


A New Method For Shear Wave Speed Estimation In Shear Wave Elastography, Aaron J. Engel, Gregory R. Bashford Dec 2015

A New Method For Shear Wave Speed Estimation In Shear Wave Elastography, Aaron J. Engel, Gregory R. Bashford

Biomedical Imaging and Biosignal Analysis Laboratory

Visualization of mechanical properties of tissue can aid in noninvasive pathology diagnosis. Shear wave elastography (SWE) measures the elastic properties of soft tissues by estimation of local shear wave propagation speed. In this paper, a new robust method for estimation of shear wave speed is introduced which has the potential for simplifying continuous filtering and real-time elasticity processing. Shear waves were generated by external mechanical excitation and imaged at a high frame rate. Three homogeneous phantoms of varying elastic moduli and one inclusion phantom were imaged. Waves propagating in separate directions were filtered and shear wave speed was estimated by ...


Homozygous Knockout Of The Piezo1 Gene In The Zebrafish Is Not Associated With Anemia, Boris E. Shmukler, Nicholas C. Huston, Jonathan N. Thon, Chih-Wen Ni, George Kourkoulis, Nathan D. Lawson, Barry H. Paw, Seth L. Alper Dec 2015

Homozygous Knockout Of The Piezo1 Gene In The Zebrafish Is Not Associated With Anemia, Boris E. Shmukler, Nicholas C. Huston, Jonathan N. Thon, Chih-Wen Ni, George Kourkoulis, Nathan D. Lawson, Barry H. Paw, Seth L. Alper

Molecular, Cell and Cancer Biology Publications

We have now examined the erythroid phenotype in this zebrafish strain carrying a ZFN genomic knockout of piezo1. Genotyping was performed as previously described. In contrast to the anemic phenotype observed in zebrafish subjected to morpholino knockdown of piezo, the genomic ZFN knockout of piezo1 did not segregate either with anemia in the 3-dpf embryo or with dysmorphic erythrocyte morphology in the adult fish.


Direct Visualization Of Hiv-1 Replication Intermediates Shows That Capsid And Cpsf6 Modulate Hiv-1 Intra-Nuclear Invasion And Integration, Christopher R. Chin, Jill Perreira, George Savidis, Jocelyn M. Portmann, Aaron M. Aker, Eric M. Feeley, Miles C. Smith, Abraham L. Brass Nov 2015

Direct Visualization Of Hiv-1 Replication Intermediates Shows That Capsid And Cpsf6 Modulate Hiv-1 Intra-Nuclear Invasion And Integration, Christopher R. Chin, Jill Perreira, George Savidis, Jocelyn M. Portmann, Aaron M. Aker, Eric M. Feeley, Miles C. Smith, Abraham L. Brass

Microbiology and Physiological Systems Publications and Presentations

Direct visualization of HIV-1 replication would improve our understanding of the viral life cycle. We adapted established technology and reagents to develop an imaging approach, ViewHIV, which allows evaluation of early HIV-1 replication intermediates, from reverse transcription to integration. These methods permit the simultaneous evaluation of both the capsid protein (CA) and viral DNA genome (vDNA) components of HIV-1 in both the cytosol and nuclei of single cells. ViewHIV is relatively rapid, uses readily available reagents in combination with standard confocal microscopy, and can be done with virtually any HIV-1 strain and permissive cell lines or primary cells. Using ViewHIV ...


Hcm1 Integrates Signals From Cdk1 And Calcineurin To Control Cell Proliferation, Heather E. Arsenault, Jagoree Roy, Claudine E. Mapa, Martha S. Cyert, Jennifer A. Benanti Oct 2015

Hcm1 Integrates Signals From Cdk1 And Calcineurin To Control Cell Proliferation, Heather E. Arsenault, Jagoree Roy, Claudine E. Mapa, Martha S. Cyert, Jennifer A. Benanti

Molecular, Cell and Cancer Biology Publications

Cyclin-dependent kinase (Cdk1) orchestrates progression through the cell cycle by coordinating the activities of cell-cycle regulators. Although phosphatases that oppose Cdk1 are likely to be necessary to establish dynamic phosphorylation, specific phosphatases that target most Cdk1 substrates have not been identified. In budding yeast, the transcription factor Hcm1 activates expression of genes that regulate chromosome segregation and is critical for maintaining genome stability. Previously we found that Hcm1 activity and degradation are stimulated by Cdk1 phosphorylation of distinct clusters of sites. Here we show that, upon exposure to environmental stress, the phosphatase calcineurin inhibits Hcm1 by specifically removing activating phosphorylations ...


Cfap54 Is Required For Proper Ciliary Motility And Assembly Of The Central Pair Apparatus In Mice, Casey W. Mckenzie, Branch Craige, Tiffany V. Kroeger, Rozzy Finn, Todd A. Wyatt, Joseph H. Sisson, Jacqueline A. Pavlik, Lara Strittmatter, Gregory M. Hendricks, George B. Witman, Lance Lee Sep 2015

Cfap54 Is Required For Proper Ciliary Motility And Assembly Of The Central Pair Apparatus In Mice, Casey W. Mckenzie, Branch Craige, Tiffany V. Kroeger, Rozzy Finn, Todd A. Wyatt, Joseph H. Sisson, Jacqueline A. Pavlik, Lara Strittmatter, Gregory M. Hendricks, George B. Witman, Lance Lee

Cell and Developmental Biology Publications

Motile cilia and flagella play critical roles in fluid clearance and cell motility, and dysfunction commonly results in the pediatric syndrome primary ciliary dyskinesia (PCD). CFAP221, also known as PCDP1, is required for ciliary and flagellar function in mice and Chlamydomonas reinhardtii, where it localizes to the C1d projection of the central microtubule apparatus and functions in a complex that regulates flagellar motility in a calcium-dependent manner. We demonstrate that the genes encoding the mouse homologues of the other C. reinhardtii C1d complex members are primarily expressed in motile ciliated tissues, suggesting a conserved function in mammalian motile cilia. The ...


Weekly Treatment Of 2-Hydroxypropyl-Beta-Cyclodextrin Improves Intracellular Cholesterol Levels In Ldl Receptor Knockout Mice, Sofie M.A. Walenbergh, Tom Houben, Tim Hendrikx, Mike L.J. Jeurissen, Patrick J. Van Gorp, Nathalie Vaes, Steven W.M. Olde Damink, Fons Verheyen, Ger H. Koek, Dieter Lutjohann, Alena Grebe, Eicke Latz, Ronit Shiri-Sverdlov Sep 2015

Weekly Treatment Of 2-Hydroxypropyl-Beta-Cyclodextrin Improves Intracellular Cholesterol Levels In Ldl Receptor Knockout Mice, Sofie M.A. Walenbergh, Tom Houben, Tim Hendrikx, Mike L.J. Jeurissen, Patrick J. Van Gorp, Nathalie Vaes, Steven W.M. Olde Damink, Fons Verheyen, Ger H. Koek, Dieter Lutjohann, Alena Grebe, Eicke Latz, Ronit Shiri-Sverdlov

Open Access Articles

Recently, the importance of lysosomes in the context of the metabolic syndrome has received increased attention. Increased lysosomal cholesterol storage and cholesterol crystallization inside macrophages have been linked to several metabolic diseases, such as atherosclerosis and non-alcoholic fatty liver disease (NAFLD). Two-hydroxypropyl-beta-cyclodextrin (HP-B-CD) is able to redirect lysosomal cholesterol to the cytoplasm in Niemann-Pick type C1 disease, a lysosomal storage disorder. We hypothesize that HP-B-CD ameliorates liver cholesterol and intracellular cholesterol levels inside Kupffer cells (KCs). Hyperlipidemic low-density lipoprotein receptor knockout (Ldlr(-/-)) mice were given weekly, subcutaneous injections with HP-B-CD or control PBS. In contrast to control injections, hyperlipidemic mice ...


Determination Of Fatty Acid Oxidation And Lipogenesis In Mouse Primary Hepatocytes, Thomas E. Akie, Marcus P. Cooper Aug 2015

Determination Of Fatty Acid Oxidation And Lipogenesis In Mouse Primary Hepatocytes, Thomas E. Akie, Marcus P. Cooper

GSBS Student Publications

Lipid metabolism in liver is complex. In addition to importing and exporting lipid via lipoproteins, hepatocytes can oxidize lipid via fatty acid oxidation, or alternatively, synthesize new lipid via de novo lipogenesis. The net sum of these pathways is dictated by a number of factors, which in certain disease states leads to fatty liver disease. Excess hepatic lipid accumulation is associated with whole body insulin resistance and coronary heart disease. Tools to study lipid metabolism in hepatocytes are useful to understand the role of hepatic lipid metabolism in certain metabolic disorders. In the liver, hepatocytes regulate the breakdown and synthesis ...


Hydrophobic Surfactant Proteins Strongly Induce Negative Curvature, Mariya Chavarha, Ryan W. Loney, Shankar B. Rananavare, Stephen B. Hall Jul 2015

Hydrophobic Surfactant Proteins Strongly Induce Negative Curvature, Mariya Chavarha, Ryan W. Loney, Shankar B. Rananavare, Stephen B. Hall

Chemistry Faculty Publications and Presentations

The hydrophobic surfactant proteins SP-B and SP-C greatly accelerate the adsorption of vesicles containing the surfactant lipids to form a film that lowers the surface tension of the air/water interface in the lungs. Pulmonary surfactant enters the interface by a process analogous to the fusion of two vesicles. As with fusion, several factors affect adsorption according to how they alter the curvature of lipid leaflets, suggesting that adsorption proceeds via a rate-limiting structure with negative curvature, in which the hydrophilic face of the phospholipid leaflets is concave. In the studies reported here, we tested whether the surfactant proteins might ...


Inducible Deletion Of Protein Kinase Map4k4 In Obese Mice Improves Insulin Sensitivity In Liver And Adipose Tissues, Laura V. Danai, Rachel J. Roth Flach, Joseph V Virbasius, Lorena Garcia Menendez, Dae Young Jung, Jong Hun Kim, Jason K. Kim, Michael P. Czech Jul 2015

Inducible Deletion Of Protein Kinase Map4k4 In Obese Mice Improves Insulin Sensitivity In Liver And Adipose Tissues, Laura V. Danai, Rachel J. Roth Flach, Joseph V Virbasius, Lorena Garcia Menendez, Dae Young Jung, Jong Hun Kim, Jason K. Kim, Michael P. Czech

Program in Molecular Medicine Publications and Presentations

Studies in vitro suggest that mitogen-activated protein kinase kinase kinase kinase 4 (Map4k4) attenuates insulin signaling, but confirmation in vivo is lacking since Map4k4 knockout is lethal during embryogenesis. We thus generated mice with floxed Map4k4 alleles and a tamoxifen-inducible Cre/ERT2 recombinase under the control of the ubiquitin C promoter to induce whole-body Map4k4 deletion after these animals reached maturity. Tamoxifen administration to these mice induced Map4k4 deletion in all tissues examined, causing decreased fasting blood glucose concentrations and enhanced insulin signaling to AKT in adipose tissue and liver but not in skeletal muscle. Surprisingly, however, mice generated with ...


Biological Significance Of Photoreceptor Photocycle Length: Vivid Photocycle Governs The Dynamic Vivid-White Collar Complex Pool Mediating Photo-Adaptation And Response To Changes In Light Intensity, Arko Dasgupta, Chen-Hui Chen, Changhwan Lee, Amy S. Gladfelter, Jay C. Dunlap, Jennifer J. Loros May 2015

Biological Significance Of Photoreceptor Photocycle Length: Vivid Photocycle Governs The Dynamic Vivid-White Collar Complex Pool Mediating Photo-Adaptation And Response To Changes In Light Intensity, Arko Dasgupta, Chen-Hui Chen, Changhwan Lee, Amy S. Gladfelter, Jay C. Dunlap, Jennifer J. Loros

Open Dartmouth: Faculty Open Access Scholarship

Most organisms on earth sense light through the use of chromophore-bearing photoreceptive proteins with distinct and characteristic photocycle lengths, yet the biological significance of this adduct decay length is neither understood nor has been tested. In the filamentous fungus Neurospora crassa VIVID (VVD) is a critical player in the process of photoadaptation, the attenuation of light-induced responses and the ability to maintain photosensitivity in response to changing light intensities. Detailed in vitro analysis of the photochemistry of the blue light sensing, FAD binding, LOV domain of VVD has revealed residues around the site of photo-adduct formation that influence the stability ...


Discovering The Sequence Specificity Of Human Dyrk2 And Dyrk4, Julie Klaric May 2015

Discovering The Sequence Specificity Of Human Dyrk2 And Dyrk4, Julie Klaric

University Scholar Projects

Protein phosphorylation is a post-translational modification (PTM) that is ubiquitous in regulating cellular processes. It is the most common PTM used in signal translation. Protein kinases are the class of enzymes that catalyze the transfer of a phosphate group from ATP to a specific amino acid on a substrate protein. In eukaryotes, kinases generally add a phosphate to serine, threonine, or tyrosine residues. Short linear patterns in the amino acid sequence of the substrate protein help guide the protein kinase to the correct residue to be phosphorylated. However, these patterns, or “motifs,” as well as the complete list of substrates ...


The Development Of Skeletal Muscle In Young Horses: An Ultrasonography And Satellite Cell Approach, Emma K. Lavigne May 2015

The Development Of Skeletal Muscle In Young Horses: An Ultrasonography And Satellite Cell Approach, Emma K. Lavigne

Honors Scholar Theses

Muscle growth in young horses is characterized by an increase in muscle cross-sectional area, which can be accomplished through the activation and differentiation of satellite cells. Satellite cells can be stimulated or inhibited in response to different cytokines and growth factors and are key mediators of muscle hypertrophy and regeneration. The aim of this study was to investigate the growth of the longissimus dorsi (LD) muscle in horses under 5 years of age and to obtain preliminary data on satellite cell behavior in foals. The area, width, height, and subcutaneous fat were measured using ultrasonography at 6-month increments over the ...


A Major Role Of Insulin In Promoting Obesity-Associated Adipose Tissue Inflammation, David J. Pedersen, Adilson L Guilherme, Laura V. Danai, Lauren Heyda, Anouch Matevossian, Jessica L. Cohen, Sarah M. Nicoloro, Juerg R. Straubhaar, Hye Lim Noh, Dae Young Jung, Jason K. Kim, Michael P. Czech May 2015

A Major Role Of Insulin In Promoting Obesity-Associated Adipose Tissue Inflammation, David J. Pedersen, Adilson L Guilherme, Laura V. Danai, Lauren Heyda, Anouch Matevossian, Jessica L. Cohen, Sarah M. Nicoloro, Juerg R. Straubhaar, Hye Lim Noh, Dae Young Jung, Jason K. Kim, Michael P. Czech

Open Access Articles

OBJECTIVE: Adipose tissue (AT) inflammation is associated with systemic insulin resistance and hyperinsulinemia in obese rodents and humans. A longstanding concept is that hyperinsulinemia may promote systemic insulin resistance through downregulation of its receptor on target tissues. Here we tested the novel hypothesis that insulin also impairs systemic insulin sensitivity by specifically enhancing adipose inflammation.

METHODS: Circulating insulin levels were reduced by about 50% in diet-induced and genetically obese mice by treatments with diazoxide or streptozotocin, respectively. We then examined AT crown-like structures, macrophage markers and pro-inflammatory cytokine expression in AT. AT lipogenesis and systemic insulin sensitivity was also monitored ...


Highly Selective In Vivo Labeling Of Subcutaneous White Adipocyte Precursors With Prx1-Cre, Joan Sanchez-Gurmaches, Wen-Yu Hsiao, David A. Guertin Apr 2015

Highly Selective In Vivo Labeling Of Subcutaneous White Adipocyte Precursors With Prx1-Cre, Joan Sanchez-Gurmaches, Wen-Yu Hsiao, David A. Guertin

Program in Molecular Medicine Publications and Presentations

The origins of individual fat depots are not well understood, and thus, the availability of tools useful for studying depot-specific adipose tissue development and function is limited. Cre drivers that selectively target only brown adipocyte, subcutaneous white adipocyte, or visceral white adipocyte precursors would have significant value because they could be used to selectively study individual depots without impacting the adipocyte precursors or intrinsic metabolic properties of the other depots. Here, we show that the majority of the precursor and mature subcutaneous white adipocytes in adult C57Bl/6 mice are labeled by Prx1-Cre. In sharp contrast, few to no brown ...


Presynaptic C-Jun N-Terminal Kinase 2 Regulates Nmda Receptor-Dependent Glutamate Release, Robert Nistico, Fulvio Florenzano, Dalila Mango, Caterina Ferraina, Massimo Grilli, Silvia Di Prisco, Annalisa Nobili, Stefania Saccucci, Marcello D'Amelio, Michela Morbin, Mario Marchi, Nicola B. Mercuri, Roger J. Davis, Anna Pittaluga, Marco Feligioni Mar 2015

Presynaptic C-Jun N-Terminal Kinase 2 Regulates Nmda Receptor-Dependent Glutamate Release, Robert Nistico, Fulvio Florenzano, Dalila Mango, Caterina Ferraina, Massimo Grilli, Silvia Di Prisco, Annalisa Nobili, Stefania Saccucci, Marcello D'Amelio, Michela Morbin, Mario Marchi, Nicola B. Mercuri, Roger J. Davis, Anna Pittaluga, Marco Feligioni

Davis Lab Publications

Activation of c-Jun N-terminal kinase (JNK) signaling pathway is a critical step for neuronal death occurring in several neurological conditions. JNKs can be activated via receptor tyrosine kinases, cytokine receptors, G-protein coupled receptors and ligand-gated ion channels, including the NMDA glutamate receptors. While JNK has been generally associated with postsynaptic NMDA receptors, its presynaptic role remains largely unexplored. Here, by means of biochemical, morphological and functional approaches, we demonstrate that JNK and its scaffold protein JIP1 are also expressed at the presynaptic level and that the NMDA-evoked glutamate release is controlled by presynaptic JNK-JIP1 interaction. Moreover, using knockout mice for ...


Myosin-Binding Protein C Corrects An Intrinsic Inhomogeneity In Cardiac Excitation-Contraction Coupling, Michael J. Previs, Benjamin L. Prosser, Ji Young Mun, Samantha Beck Previs, James Gulick, Kyounghwan Lee, Jeffrey Robbins, Roger Craig, W J. Lederer, David M. Warshaw Feb 2015

Myosin-Binding Protein C Corrects An Intrinsic Inhomogeneity In Cardiac Excitation-Contraction Coupling, Michael J. Previs, Benjamin L. Prosser, Ji Young Mun, Samantha Beck Previs, James Gulick, Kyounghwan Lee, Jeffrey Robbins, Roger Craig, W J. Lederer, David M. Warshaw

Cell and Developmental Biology Publications

The beating heart exhibits remarkable contractile fidelity over a lifetime, which reflects the tight coupling of electrical, chemical, and mechanical elements within the sarcomere, the elementary contractile unit. On a beat-to-beat basis, calcium is released from the ends of the sarcomere and must diffuse toward the sarcomere center to fully activate the myosin- and actin-based contractile proteins. The resultant spatial and temporal gradient in free calcium across the sarcomere should lead to nonuniform and inefficient activation of contraction. We show that myosin-binding protein C (MyBP-C), through its positioning on the myosin thick filaments, corrects this nonuniformity in calcium activation by ...


Fhl1 Reduces Dystrophy In Transgenic Mice Overexpressing Fshd Muscular Dystrophy Region Gene 1 (Frg1), Sandra J. Feeney, Meagan J. Mcgrath, Absorn Sriratana, Stefan M. Gehrig, Gordon S. Lynch, Colleen E. D'Arcy, John T. Price, Catriona A. Mclean, Rossella Ginevra Tupler, Christina A. Mitchell Feb 2015

Fhl1 Reduces Dystrophy In Transgenic Mice Overexpressing Fshd Muscular Dystrophy Region Gene 1 (Frg1), Sandra J. Feeney, Meagan J. Mcgrath, Absorn Sriratana, Stefan M. Gehrig, Gordon S. Lynch, Colleen E. D'Arcy, John T. Price, Catriona A. Mclean, Rossella Ginevra Tupler, Christina A. Mitchell

Open Access Articles

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal-dominant disease with no effective treatment. The genetic cause of FSHD is complex and the primary pathogenic insult underlying the muscle disease is unknown. Several disease candidate genes have been proposed including DUX4 and FRG1. Expression analysis studies of FSHD report the deregulation of genes which mediate myoblast differentiation and fusion. Transgenic mice overexpressing FRG1 recapitulate the FSHD muscular dystrophy phenotype. Our current study selectively examines how increased expression of FRG1 may contribute to myoblast differentiation defects. We generated stable C2C12 cell lines overexpressing FRG1, which exhibited a myoblast fusion defect upon differentiation. To ...


Drug-Resistant Hiv-1 Protease Regains Functional Dynamics Through Cleavage Site Coevolution, Nevra Ozer, Aysegul Ozen, Celia A. Schiffer, Turkan Haliloglu Feb 2015

Drug-Resistant Hiv-1 Protease Regains Functional Dynamics Through Cleavage Site Coevolution, Nevra Ozer, Aysegul Ozen, Celia A. Schiffer, Turkan Haliloglu

University of Massachusetts Medical School Faculty Publications

Drug resistance is caused by mutations that change the balance of recognition favoring substrate cleavage over inhibitor binding. Here, a structural dynamics perspective of the regained wild-type functioning in mutant HIV-1 proteases with coevolution of the natural substrates is provided. The collective dynamics of mutant structures of the protease bound to p1-p6 and NC-p1 substrates are assessed using the Anisotropic Network Model (ANM). The drug-induced protease mutations perturb the mechanistically crucial hinge axes that involve key sites for substrate binding and dimerization and mainly coordinate the intrinsic dynamics. Yet with substrate coevolution, while the wild-type dynamic behavior is restored in ...


Theoretical Investigation Of Intra- And Inter-Cellular Spatiotemporal Calcium Patterns In Microcirculation, Jaimit B. Parikh Jan 2015

Theoretical Investigation Of Intra- And Inter-Cellular Spatiotemporal Calcium Patterns In Microcirculation, Jaimit B. Parikh

FIU Electronic Theses and Dissertations

Microcirculatory vessels are lined by endothelial cells (ECs) which are surrounded by a single or multiple layer of smooth muscle cells (SMCs). Spontaneous and agonist induced spatiotemporal calcium (Ca2+) events are generated in ECs and SMCs, and regulated by complex bi-directional signaling between the two layers which ultimately determines the vessel tone. The contractile state of microcirculatory vessels is an important factor in the determination of vascular resistance, blood flow and blood pressure. This dissertation presents theoretical insights into some of the important and currently unresolved phenomena in microvascular tone regulation. Compartmental and continuum models of isolated EC and ...


Uncoupling Lifespan And Healthspan In Caenorhabditis Elegans Longevity Mutants, Ankita Bansal, Lihua Julie Zhu, Kelvin Yen, Heidi A. Tissenbaum Jan 2015

Uncoupling Lifespan And Healthspan In Caenorhabditis Elegans Longevity Mutants, Ankita Bansal, Lihua Julie Zhu, Kelvin Yen, Heidi A. Tissenbaum

Molecular, Cell and Cancer Biology Publications

Aging research has been very successful at identifying signaling pathways and evolutionarily conserved genes that extend lifespan with the assumption that an increase in lifespan will also increase healthspan. However, it is largely unknown whether we are extending the healthy time of life or simply prolonging a period of frailty with increased incidence of age-associated diseases. Here we use Caenorhabditis elegans, one of the premiere systems for lifespan studies, to determine whether lifespan and healthspan are intrinsically correlated. We conducted multiple cellular and organismal assays on wild type as well as four long-lived mutants (insulin/insulin-like growth factor-1, dietary restriction ...


Functional Transcranial Doppler Ultrasound For High Temporal Resolution Measurement Of Lateralization In Visual Memory And Visual Search Cognitive Tasks, B. Hage, M. Alwatban, E. Barney, M. Mills, M. Dodd, E. Truemper, Gregory R. Bashford Jan 2015

Functional Transcranial Doppler Ultrasound For High Temporal Resolution Measurement Of Lateralization In Visual Memory And Visual Search Cognitive Tasks, B. Hage, M. Alwatban, E. Barney, M. Mills, M. Dodd, E. Truemper, Gregory R. Bashford

Biomedical Imaging and Biosignal Analysis Laboratory

Functional transcranial Doppler ultrasound (fTCD) is a noninvasive sensing modality that measures blood flow velocities in cerebral arteries (CBFV) with high temporal resolution. Few studies have examined the relationship of CBFV change during visual search and visual memory cognitive tasks. Here a protocol to compare lateralization between these two similar tasks using fTCD is demonstrated. Thirteen healthy volunteers were shown visual scenes on a computer and performed visual search and visual memory tasks while CBFV in the bilateral middle cerebral arteries was monitored with fTCD. Each subject completed 40 trials, consisting of baseline, calibration, instruction, and task periods. Lateralization was ...


Enabling Real-Time Ultrasound Imaging Of Soft Tissue Mechanical Properties By Simplification Of The Shear Wave Motion Equation, Aaron J. Engel, Gregory R. Bashford Jan 2015

Enabling Real-Time Ultrasound Imaging Of Soft Tissue Mechanical Properties By Simplification Of The Shear Wave Motion Equation, Aaron J. Engel, Gregory R. Bashford

Biomedical Imaging and Biosignal Analysis Laboratory

Ultrasound based shear wave elastography (SWE) is a technique used for non-invasive characterization and imaging of soft tissue mechanical properties. Robust estimation of shear wave propagation speed is essential for imaging of soft tissue mechanical properties. In this study we propose to estimate shear wave speed by inversion of the firstorder wave equation following directional filtering. This approach relies on estimation of first-order derivatives which allows for accurate estimations using smaller smoothing filters than when estimating second-order derivatives. The performance was compared to three current methods used to estimate shear wave propagation speed: direct inversion of the wave equation (DIWE ...


Oxygenation Properties And Isoform Diversity Of Snake Hemoglobins, Jay F. Storz, Chandrasekhar Natarajan, Hideaki Moriyama, Federico G. Hoffmann, Tobias Wang, Angela Fago, Hans Malte, Johannes Overgaard, Roy E. Weber Jan 2015

Oxygenation Properties And Isoform Diversity Of Snake Hemoglobins, Jay F. Storz, Chandrasekhar Natarajan, Hideaki Moriyama, Federico G. Hoffmann, Tobias Wang, Angela Fago, Hans Malte, Johannes Overgaard, Roy E. Weber

Jay F. Storz Publications

Available data suggest that snake hemoglobins (Hbs) are characterized by a combination of unusual structural and functional properties relative to the Hbs of other amniote vertebrates, including oxygenation-linked tetramer-dimer dissociation. However, standardized comparative data are lacking for snake Hbs, and the Hb isoform composition of snake red blood cells has not been systematically characterized. Here we present the results of an integrated analysis of snake Hbs and the underlying α- and β-type globin genes to characterize 1) Hb isoform composition of definitive erythrocytes, and 2) the oxygenation properties of isolated isoforms as well as composite hemolysates. We used species from ...


Human Anatomy And Physiology Preparatory Course, Carlos Liachovitzky Jan 2015

Human Anatomy And Physiology Preparatory Course, Carlos Liachovitzky

Open Educational Resources

The overall purpose of this preparatory course textbook is to help students familiarize with some terms and some basic concepts they will find later in the Human Anatomy and Physiology I course.

The organization and functioning of the human organism generally is discussed in terms of different levels of increasing complexity, from the smallest building blocks to the entire body. This Anatomy and Physiology preparatory course covers the foundations on the chemical level, and a basic introduction to cellular level, organ level, and organ system levels. There is also an introduction to homeostasis at the beginning.


Clique Topology Reveals Intrinsic Geometric Structure In Neural Correlations, Chad Giusti, Eva Pastalkova, Carina Curto, Vladimir Itskov Jan 2015

Clique Topology Reveals Intrinsic Geometric Structure In Neural Correlations, Chad Giusti, Eva Pastalkova, Carina Curto, Vladimir Itskov

Faculty Publications, Department of Mathematics

Detecting meaningful structure in neural activity and connectivity data is challenging in the presence of hidden nonlinearities, where traditional eigenvalue-based methods may be misleading. We introduce a novel approach to matrix analysis, called clique topology, that extracts features of the data invariant under nonlinear monotone transformations. These features can be used to detect both random and geometric structure, and depend only on the relative ordering of matrix entries. We then analyzed the activity of pyramidal neurons in rat hippocampus, recorded while the animal was exploring a 2D environment, and confirmed that our method is able to detect geometric organization using ...


Picosecond To Terahertz Perturbation Of Interfacial Water And Electropermeabilization Of Biological Membranes, P. Thomas Vernier, Zachary A. Levine, Ming-Chak Ho, Shu Xiao, Iurii Semenov, Andrei G. Pakhomov Jan 2015

Picosecond To Terahertz Perturbation Of Interfacial Water And Electropermeabilization Of Biological Membranes, P. Thomas Vernier, Zachary A. Levine, Ming-Chak Ho, Shu Xiao, Iurii Semenov, Andrei G. Pakhomov

Bioelectrics Publications

Non-thermal probing and stimulation with subnanosecond electric pulses and terahertz electromagnetic radiation may lead to new, minimally invasive diagnostic and therapeutic procedures and to methods for remote monitoring and analysis of biological systems, including plants, animals, and humans. To effectively engineer these still-emerging tools, we need an understanding of the biophysical mechanisms underlying the responses that have been reported to these novel stimuli. We show here that subnanosecond (≤500 ps) electric pulses induce action potentials in neurons and cause calcium transients in neuroblastoma-glioma hybrid cells, and we report complementary molecular dynamics simulations of phospholipid bilayers in electric fields in which ...


Introduction To Fifth Special Issue On Electroporation-Based Technologies And Treatments, Damijan Miklavčič, Lluis M. Mir, P. Thomas Vernier Jan 2015

Introduction To Fifth Special Issue On Electroporation-Based Technologies And Treatments, Damijan Miklavčič, Lluis M. Mir, P. Thomas Vernier

Bioelectrics Publications

This special issue of the Journal of Membrane Biology contains reports on recent developments in the field of electroporation by participants in the International Workshop and Postgraduate Course on Electroporation-Based Technologies and Treatments held in November 2014 in Ljubljana. This was the eighth session of what is now an annual event, first organized in 2003.