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  • Articles  (15)
  • Ca2+ release
  • Ca2+ uptake
  • Nonlinear waves
  • Ocean heat content
  • 2020-2024  (1)
  • 2005-2009  (4)
  • 1990-1994  (8)
  • 1980-1984  (2)
Collection
  • Articles  (15)
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Keywords
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Years
Year
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  • 1
    Electronic Resource
    Electronic Resource
    Sulfhydryl oxidation induces calcium release from fragmented sarcoplasmic reticulum even in the presence of glutathione (1993)
    Springer
    Cellular and molecular life sciences 49 (1993), S. 282-284 
    Details
    ISSN: 1420-9071
    Keywords: Sarcoplasmic reticulum ; Ca2+ release ; sulfhydryl oxidation ; alcian blue ; plumbagin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Alcian blue and plumbagin induced transient Ca2+ release from fragmented sarcoplasmic reticulum. Dithiothreitol (DTT) and glutathione (GSH) partially blocked Ca2+ release induced by these oxidizing compounds. Pretreatment of alcian blue and plumbagin with DTT or GSH for more than 1 min was required to abolish the ability of the oxidizing compounds to release Ca2+. Mg2+ and ruthenium red completely blocked alcian blue-and plumbagin-induced Ca2+ release. These results suggest that oxidation of sulfhydryls on Ca2+ release channels induces Ca2+ release even in the presence of GSH in situ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01923402
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of retinoic acid on liver transglutaminase activity and carbon tetrachloride-induced liver damage in mice (1992)
    Springer
    Cellular and molecular life sciences 48 (1992), S. 386-388 
    Details
    ISSN: 1420-9071
    Keywords: Retinoic acid ; transglutaminase ; liver damage ; carbon tetrachloride ; serum alanine transaminase ; Ca2+ uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Transglutaminase (TGase) activity in the cytosol fraction of the mouse liver increased following intraperitoneal injection of retinoic acid. Retinoic acid inhibited the carbon tetrachloride-induced increase in serum alanine transaminase activity. These findings suggest that TGase is involved in the effect of retinoic acid on carbon tetrachloride-induced liver damage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01923436
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  • 3
    Electronic Resource
    Electronic Resource
    Impaired calcium uptake by cardiac sarcoplasmic reticulum and its underlying mechanism in endotoxin shock (1991)
    Springer
    Molecular and cellular biochemistry 108 (1991), S. 9-17 
    Details
    ISSN: 1573-4919
    Keywords: endotoxin shock ; heart sarcoplasmic reticulum ; Ca2+ transport ; ATP-dependent ; Ca2+ uptake ; membrane phosphorylation ; dephosphorylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Effects of endotoxin administration on the ATP-dependent Ca2+ uptake by canine cardiac sarcoplasmic reticulum (SR) were investigated. Results obtained 4 h after endotoxin administration show that ATP-dependent Ca2+ uptake by cardiac SR was decreased by 27–43% (p 〈 0.05). Kinetic analysis indicates that the Vmax values for Ca2+ and for ATP were significantly decreased while the S0.5 and the Hill coefficient values were not affected during endotoxin shock. Magnesium (1–5 mM) stimulated while vanadate (25–50 μM) inhibited the ATP-dependent Ca2+ uptake, but the Mg2+-stimulated and the vanadate-inhibited activities remained significantly lower in the endotoxin-treated animals. Phosphorylation of SR by the exogenously added catalytic subunit of the cAMP-dependent protein kinase or by the addition of calmodulin stimulated the ATP-dependent Ca2+ uptake activities both in the control and endotoxin-injected dogs. However, the phosphorylation-stimulated activities remained significantly lower in the endotoxin-injected dogs. Dephosphorylation of SR decreased the ATP-dependent Ca2+ uptake, but the half-time required for the maximal dephosphorylation was reduced by 31% (p 〈 0.05) 4 h post-endotoxin. These data indicate that endotoxin administration impairs the ATP-dependent Ca2+ uptake in canine cardiac SR and the endotoxininduced impairment in the SR calcium transport is associated with a mechanism involving a defective phosphorylation and an accelerated dephosphorylation of SR membrane protein. Since ATP-dependent Ca2+ uptake by cardiac SR plays an important role in the regulation of the homeostatic levels of the contractile calcium, our findings may provide a biochemical explanation for myocardial dysfunction that occurs during endotoxin shock.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239537
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  • 4
    Electronic Resource
    Electronic Resource
    Heart sarcolemmal Ca2+ transport in endotoxin shock: I. Impairment of ATP-dependent Ca2+ transport (1992)
    Springer
    Molecular and cellular biochemistry 112 (1992), S. 125-133 
    Details
    ISSN: 1573-4919
    Keywords: endotoxin shock ; dog heart ; cardiac sarcolemma ; Ca2+ transport ; Ca2+ uptake ; Ca2+-ATPase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Effects of endotoxin administration on the ATP-dependent Ca2+ transport in canine cardiac sarcolemma were investigated. The results show that the sidedness of the sarcolemmal vesicles was not affected but the ATP-dependent Ca2+ transport in cardiac sarcolemma was decreased by 22 to 46% (p 〈 0.05) at 4 h following endotoxin administration. The kinetic analysis indicates that the Vmax for ATP and for Ca2+ were decreased by 50% (p 〈 0.01) and 32% (p 〈 0.01), respectively, while the Km values for ATP and Ca2+ were not significantly affected after endotoxin administration. Magnesium (1–5 mM) stimulated while vanadate (0.25–3.0 μM) inhibited the ATP-dependent Ca2+ transport, but the Mg2+-stimulated and the vanadate-inhibitable activities remained significantly lower in the endotoxin-treated animals. These data demonstrate that endotoxin administration impairs the ATP-dependent Ca2+ transport in canine cardiac sarcolemma and that the impairment is associated with a mechanism not affecting the affinity towards ATP and Ca2+. Additional experiments show that the Ca2+ sensitivity of the Ca2+-ATPase activity was indifferent between the control and endotoxic groups suggesting that endotoxic injury impairs Ca2+ pumping without affecting Ca2+-ATPase activity. Since sarcolemmal ATP-dependent Ca2+ transport plays an important role in the regulation of cytosolic Ca2+ homeostasis, an impairment in the sarcolemmal ATP-dependent Ca2+ transport induced by endotoxin administration may have a pathophysiological significance in contributing to the development of myocardial dysfunction in endotoxin shock.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227569
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  • 5
    Electronic Resource
    Electronic Resource
    Stabilization of rat cardiac sacroplasmic reticulum Ca2+ uptake activity and isolation of vesicles with improved calcium uptake activity (1990)
    Springer
    Molecular and cellular biochemistry 99 (1990), S. 41-52 
    Details
    ISSN: 1573-4919
    Keywords: cardiac sarcoplasmic reticulum ; Ca2+-ATPase ; Ca2+ uptake ; rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summmary The Ca2+ uptake activity of rat cardiac sacroplasmic reticulum (CSR) in ventricular homogenates is highly unstable, and this instability probably accounts for the low specific activity of Ca2+ uptake in previously reported fractions of isolated rat CSR. The instability was observed at either 0° or 37°, but the Ca2+ uptake activity was relatively stable at 25°. The decay of Ca2+ uptake activity at 0° could not be prevented by either PMSF or leupeptin, but dithiothreitol exerted some protective effects. Sodium metabisulfite prevented decay of the Ca2+ uptake activity of homogenates kept on ice but not of homogenates kept at 37°. We also found that release of the CSR from the cellular debris required homogenization in high KCI. This distinguishes rat CSR from canine CSR. Isolated CSR was produced by a combination of differential centrifugation and discontinuous sucrous gradient centrifugation. The average rate of the sustained oxalate-supported calcium uptake in the resulting CSR fraction was 0.36 μmol/min-mg in the absence of CSR calcium channel blockers and 0.67 μmol/min/mg in the presence of 10 μM ruthenium red. Thus, this preparation has the advantage of containing both the releasing and non-releasing fractions of the CSR. The Ca2+-ATPase rates averaged 1.07 μmol/min/mg and 0.88 μmol/min-mg in the absence and presence of ruthenium red, respectively. Although these rates are higher than previously reported rates, this CSR preparation should still be considered a ‘crude’ preparation. A major distinction between the rat CSR and dog CSR was the lower content of Ca2+-ATPase in rat CSR, as judged by SDS-PAGE. Preparations of CSR isolated by this method may be useful in evaluating alterations in CSR function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01261392
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  • 6
    Electronic Resource
    Electronic Resource
    Osmotic changes of sarcoplasmic reticulum vesicles during Ca2+ uptake (1983)
    Springer
    The journal of membrane biology 76 (1983), S. 165-171 
    Details
    ISSN: 1432-1424
    Keywords: sarcoplasmic reticulum ; Ca2+-ATPase ; Ca2+ transport ; Ca2+ release ; osmotic swelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The ATP-dependent accumulation of Ca2+ by sarcoplasmic reticulum vesicles at 37° C reaches a peak after approximately 100 sec. The Ca2+-loading level then declines until a steady-state level is reached which is 20% less than the peak value. This spontaneous release of Ca2+ is enhanced by inclusion of maleate in the Ca2+ uptake medium. Increasing the extravesicular osmolarity by the addition of sucrose to the Ca2+ uptake medium prevents spontaneous Ca2+ release and increases the steady-state Ca2+-loading capacity of sarcoplasmic reticulum vesicles. Swelling of sarcoplasmic reticulum vesicles during Ca2+ uptake in medium containing sucrose is indicated by changes in the light-scattering intensity. These experiments indicate that the capacity of sarcoplasmic reticulum vesicles to accumulate Ca2+ is limited by the osmotic gradient generated by the increase in intravesicular Ca2+. Swelling of sarcoplasmic reticulum vesicles during Ca2+ uptake causes spontaneous Ca2+ release.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02000616
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  • 7
    Electronic Resource
    Electronic Resource
    Excitation-contraction coupling in a pre-vertebrate twitch muscle: The myotomes of Branchiostoma lanceolatum (1992)
    Springer
    The journal of membrane biology 129 (1992), S. 237-252 
    Details
    ISSN: 1432-1424
    Keywords: muscle ; excitation-contraction coupling ; ryanodine receptor ; Ca2+ current ; dihydropyridine receptor ; Ca2+ release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The segmented trunk muscle (myotome muscle) of the lancelet (Branchiostoma lanceolatum), a pre-vertebrate chordate, was studied in order to gain information regarding the evolution of excitation-contraction (EC) coupling. Myotome membrane vesicles could be separated on isopycnic sucrose gradients into two main fractions, probably comprising solitary microsomes and diads of plasma membrane and sarcoplasmic reticulum, respectively. Both fractions bound the dihydropyridine PN 200/110 and the phenylalkylamine (−)D888 (devapamil) while specific ryanodine binding was observed in the diad preparation only. Pharmacological effects on Ca2+ currents measured under voltage-clamp conditions in single myotome fibers included a weak block by the dihydropyridine nifedipine and a shift of the voltage dependences of inactivation and restoration to more negative potentials by (−)D888. After blocking the Ca2+ current by cadmium in voltage-clamped single fibers, the contractile response persisted and a rapid intramembrane charge movement could be demonstrated. Both responses exhibited a voltage sensitivity very similar to the one of the voltage-activated Ca2+ channels. Our biochemical and electrophysiological results indicate that the EC coupling mechanism of the protochordate myotome cell is similar to that of the vertebrate skeletal muscle fiber: Intracellular Ca2+ release, presumably taking place via the ryanodine receptor complex, is under control of the cell membrane potential. The sarcolemmal Ca2+ channels might serve as voltage sensors for this process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232906
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  • 8
    Electronic Resource
    Electronic Resource
    Mechanism of calcium release from skeletal sarcoplasmic reticulum (1982)
    Springer
    The journal of membrane biology 66 (1982), S. 193-201 
    Details
    ISSN: 1432-1424
    Keywords: sarcoplasmic reticulum ; Ca2+ release ; excitation-contraction coupling ; muscular contraction ; valinomycin ; ruthenium red
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Ca2+-induced Ca2+ release at the terminal cisternae of skeletal sarcoplasmic reticulum was demonstrated using heavy sarcoplasmic reticulum vesicles. Ca2+ release was observed at 10 μm Ca2+ in the presence of 1.25mm free Mg2+ and was sensitive to low concentrations of ruthenium red and was partially inhibited by valinomycin. These results suggest that the Ca2+-induced Ca2+ release is electrogenic and that an inside negative membrane potential created by the Ca2+ flux opens a second channel that releases Ca2+. Results in support of this formulation were obtained by applying a Cl− gradient or K+ gradient to sarcoplasmic reticulum vesicles to initiate Ca2+ release. Based on experiments the following hypothesis for the excitation-contraction coupling of skeletal muscle was formulated. On excitation, small amounts of Ca2+ enter from the transverse tubule and interact with a Ca2+ receptor at the terminal cisternae and cause Ca2+ release (Ca2+-induced Ca2+ release). This Ca2+ flux generates an inside negative membrane potential which opens voltage-gated Ca2+ channels (membrane potential-dependent Ca2+ release) in amounts sufficient for contraction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01868494
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  • 9
    Electronic Resource
    Electronic Resource
    Endogenous, Ca2+-dependent cysteine-protease cleaves specifically the ryanodine receptor/Ca2+ release channel in skeletal muscle (1994)
    Springer
    The journal of membrane biology 142 (1994), S. 281-288 
    Details
    ISSN: 1432-1424
    Keywords: Ryanodine receptor ; Ca2+ release channel ; Calpain ; Junctional sarcoplasmic reticulum ; Ca2+ release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The association of an endogenous, Ca2+-dependent cysteine-protease with the junctional sarcoplasmic reticulum (SR) is demonstrated. The activity of this protease is strongly stimulated by dithiothreitol (DTT), cysteine and β-mercaptoethanol, and is inhibited by iodoacetamide, mercuric chloride and leupeptin, but not by PMSF. The activity of this thiol-protease is dependent on Ca2+ with half-maximal activity obtained at 0.1 μm and maximal activity at 10 μm. Mg2+ is also an activator of this enzyme (CI50=22 μm). These observations, together with the neutral pH optima and inhibition by the calpain I inhibitor, suggest that this enzyme is of calpain I type. This protease specifically cleaves the ryanodine receptor monomer (510 kD) at one site to produce two fragments with apparent molecular masses of 375 and 150 kD. The proteolytic fragments remain associated as shown by purification of the cleaved ryanodine receptor. The calpain binding site is identified as a PEST (proline, glutamic acid, serine, threonine-rich) region in the amino acid sequence GTPGGTPQPGVE, at positions 1356–1367 of the RyR and the cleavage site, the calmodulin binding site, at residues 1383–1400. The RyR cleavage by the Ca2+-dependent thiol-protease is prevented in the presence of ATP (1–5 mm) and by high NaCl concentrations. This cleavage of the RyR has no effect on ryanodine binding activity but stimulates Ca2+ efflux. A possible involvement of this specific cleavage of the RyR/Ca2+ release channel in the control of calpain activity is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233435
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of cold shock and phospholipase A2 on intact boar spermatozoa and sperm head plasma membranes (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 26 (1990), S. 143-149 
    Details
    ISSN: 1040-452X
    Keywords: Fertility ; Ca2+ uptake ; Head plasma membrane ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Head plasma membranes (HPM) isolated from cryopreserved boar spermatozoa show an excessive fluidization (Buhr et al., Gamete Res 23:441-449, 1989), which might be involved in the loss of fertility. The current study assessed the ability of cold shock (5°C) and phospholipase A2 (PA2) to duplicate these effects on membrane structure and to affect 45Ca2+ uptake and gross morphological characteristics of whole, fresh boar sperm. The HPM from cold-shocked sperm showed a significantly greater rate of fluidization over time than did HPM from control sperm. Addition of PA2 (bee or snake venom, 0.1 or 10.0 ng/ml) to HPM from control sperm caused fluidization similar to cold shocking, but to a lesser degree (P 〈 0.05). Cold-shocked intact sperm exhibited severe acrosomal disruption, loss of motility, and increased 45Ca2+ uptake relative to control sperm. Addition of PA2 (bee or snake venom, 0.1, 1.0., 10.0, and 1,000 ng/ml) to control sperm had not effect on gross morphology or motility while maintaining or increasing sperm extrusion of 45Ca2+. Therefore, although PA2 can, to some extent, duplicate the effects of cold shock on HPM molecular organization, its lipid hydrolytic action is insufficient to cause all the gross disruptions of severe thermal shock. Both PA2 and cold shock disrupted HPM structure, but only cold shock increased 45Ca2+ uptake, suggesting that cold shock may be increasing 45Ca2+ uptake in areas other than the head. Cold shock disrupts sperm on three levels; membrane molecular organization, intracellular Ca2+ regulation, and gross morphology/motility.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080260208
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  • 11
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    Long nonlinear internal waves (2006)
    Annual Reviews
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    Publication Date: 2022-05-25
    Description: Author Posting. © Annual Reviews, 2006. This article is posted here by permission of Annual Reviews for personal use, not for redistribution. The definitive version was published in Annual Review of Fluid Mechanics 38 (2006): 395-425, doi:10.1146/annurev.fluid.38.050304.092129.
    Description: Over the past four decades, the combination of in situ and remote sensing observations has demonstrated that long nonlinear internal solitary-like waves are ubiquitous features of coastal oceans. The following provides an overview of the properties of steady internal solitary waves and the transient processes of wave generation and evolution, primarily from the point of view of weakly nonlinear theory, of which the Korteweg-de Vries equation is the most frequently used example. However, the oceanographically important processes of wave instability and breaking, generally inaccessible with these models, are also discussed. Furthermore, observations often show strongly nonlinear waves whose properties can only be explained with fully nonlinear models.
    Description: KRH acknowledges support from NSF and ONR and an Independent Study Award from the Woods Hole Oceanographic Institution. WKM acknowledges support from NSF and ONR, which has made his work in this area possible, in close collaboration with former graduate students at Scripps Institution of Oceanography and MIT.
    Keywords: Solitary waves ; Nonlinear waves ; Stratified flow ; Physical Oceanography
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 12
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    Internal tide and nonlinear internal wave behavior at the continental slope in the northern south China Sea (2006)
    IEEE
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © IEEE, 2004. This article is posted here by permission of IEEE for personal use, not for redistribution. The definitive version was published in IEEE Journal of Oceanic Engineering 29 (2004): 1105-1130, doi:10.1109/JOE.2004.836998.
    Description: A field program to measure acoustic propagation characteristics and physical oceanography was undertaken in April and May 2001 in the northern South China Sea. Fluctuating ocean properties were measured with 21 moorings in water of 350- to 71-m depth near the continental slope. The sea floor at the site is gradually sloped at depths less than 90 m, but the deeper area is steppy, having gradual slopes over large areas that are near critical for diurnal internal waves and steep steps between those areas that account for much of the depth change. Large-amplitude nonlinear internal gravity waves incident on the site from the east were observed to change amplitude, horizontal length scale, and energy when shoaling. Beginning as relatively narrow solitary waves of depression, these waves continued onto the shelf much broadened in horizontal scale, where they were trailed by numerous waves of elevation (alternatively described as oscillations) that first appeared in the continental slope region. Internal gravity waves of both diurnal and semidiurnal tidal frequencies (internal tides) were also observed to propagate into shallow water from deeper water, with the diurnal waves dominating. The internal tides were at times sufficiently nonlinear to break down into bores and groups of high-frequency nonlinear internal waves.
    Description: This work was supported in part by grants from the U.S. Office of Naval Research, Physical Oceanography and Ocean Acoustics Programs, and by the National Science Council of Taiwan.
    Keywords: Baroclinic tides ; Internal waves ; Nonlinear waves
    Repository Name: Woods Hole Open Access Server
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  • 13
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    Nonlinear adjustment of a localized layer of buoyant, uniform potential vorticity fluid against a vertical wall (2007)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Elsevier B.V., 2006. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Dynamics of Atmospheres and Oceans 41 (2006): 149-171, doi:10.1016/j.dynatmoce.2006.02.001.
    Description: The nonlinear evolution of a localized layer of buoyant, uniform potential vorticity fluid of uniform depth H, width w0 and length L released adjacent to a wall in a rotating system is studied using reduced-gravity shallow-water theory and numerical modeling. In the interior, far from the two ends of the layer, the initial adjustment gives, after ignoring inertia-gravity waves, a geostrophic flow of width w∞ and layer velocities parallel to the wall directed in the downstream direction (defined by Kelvin wave propagation). This steady geostrophic flow serves as the initial condition for a semigeostrophic solution using the method of characteristics. At the downstream end, the theory shows that the fluid intrudes along the wall as rarefaction terminating at a nose of vanishing width and depth. However, in a real fluid the presence of the lower layer leads to a blunt gravity current head. The theory is amended by introducing a gravity current head condition that has a blunt bore joined to the rarefaction by a uniform gravity current. The upstream termination of the initial layer produces a Kelvin rarefaction that propagates downstream, decreasing the layer depth along the wall, and initiating upstream flow adjacent to the wall. The theoretical solution compares favorably to numerical solutions of the reduced-gravity shallow-water equations. The agreement between theory and numerical solutions occurs regardless of whether the numerical runs are initiated with an adjusted geostrophic solution or with the release of a stagnant layer. The latter case excites inertia-gravity waves that, despite their large amplitude and breaking, do not significantly affect the evolution of the geostrophic flow. At times beyond the validity of the semigeostrophic theory, the numerical solutions evolve into a stationary arrays of vortices. The vortex formation can be interpreted as the finite-amplitude manifestation of a linear instability of the new flow established by the passage of the Kelvin wave. The Kelvin wave ultimately reduces the flux into the downstream gravity current and the vortices retain buoyant in the neighborhood of the initial layer.
    Description: This work was supported by NSF Grant OCE-0325102.
    Keywords: Geostrophic adjustment ; Gravity currents ; Kelvin waves ; Nonlinear waves ; Vortices
    Repository Name: Woods Hole Open Access Server
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  • 14
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    Design and function of superfast muscles : new insights into the physiology of skeletal muscle (2005)
    Annual Reviews
    Details
    Publication Date: 2022-05-25
    Description: First published online as a Review in Advance on October 24, 2005. (Some corrections may occur before final publication online and in print)
    Description: Author Posting. © Annual Reviews, 2005. This article is posted here by permission of Annual Reviews for personal use, not for redistribution. The definitive version was published in Annual Review of Physiology 68 (2006): 22.1-22.29, doi:10.1146/annurev.physiol.68.040104.105418.
    Description: Superfast muscles of vertebrates power sound production. The fastest, the swimbladder muscle of toadfish, generates mechanical power at frequencies in excess of 200 Hz. To operate at these frequencies, the speed of relaxation has had to increase approximately 50-fold. This increase is accomplished by modifications of three kinetic traits: (a) a fast calcium transient due to extremely high concentration of sarcoplasmic reticulum (SR)-Ca2+ pumps and parvalbumin, (b) fast off-rate of Ca2+ from troponin C due to an alteration in troponin, and (c) fast cross-bridge detachment rate constant (g, 50 times faster than that in rabbit fast-twitch muscle) due to an alteration in myosin. Although these three modifications permit swimbladder muscle to generate mechanical work at high frequencies (where locomotor muscles cannot), it comes with a cost: The high g causes a large reduction in attached force-generating cross-bridges, making the swimbladder incapable of powering low-frequency locomotory movements. Hence the locomotory and sound-producing muscles have mutually exclusive designs.
    Description: This work was made possible by support from NIH grants AR38404 and AR46125 as well as the University of Pennsylvania Research Foundation.
    Keywords: Parvalbumin ; Ca2+ release ; Ca2+ uptake ; Cross-bridges ; Adaptation ; Sound production ; Whitman Center
    Repository Name: Woods Hole Open Access Server
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  • 15
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    The Arctic Ocean’s Beaufort Gyre (2023)
    Annual Reviews
    Details
    Publication Date: 2023-02-28
    Description: © The Author(s), 2023. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Timmermans, M.-L., & Toole, J. The Arctic Ocean’s Beaufort Gyre. Annual Review of Marine Science, 15(1), (2023): 223-248, https://doi.org/10.1146/annurev-marine-032122-012034.
    Description: The Arctic Ocean's Beaufort Gyre is a dominant feature of the Arctic system, a prominent indicator of climate change, and possibly a control factor for high-latitude climate. The state of knowledge of the wind-driven Beaufort Gyre is reviewed here, including its forcing, relationship to sea-ice cover, source waters, circulation, and energetics. Recent decades have seen pronounced change in all elements of the Beaufort Gyre system. Sea-ice losses have accompanied an intensification of the gyre circulation and increasing heat and freshwater content. Present understanding of these changes is evaluated, and time series of heat and freshwater content are updated to include the most recent observations.
    Description: Support was provided by the National Science Foundation Office of Polar Programs and the Office of Naval Research.
    Keywords: Arctic Ocean ; Beaufort Gyre ; Circulation ; Sea ice ; Freshwater ; Ocean heat content
    Repository Name: Woods Hole Open Access Server
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