Structural and functional recovery of electropermeabilized skeletal muscle in-vivo after treatment with surfactant poloxamer 188

A critical requirement for cell survival after trauma is sealing of breaks in the cell membrane [M. Bier, S.M. Hammer, D.J. Canaday, R.C Lee, Kinetics of sealing for transient electropores in isolated mammalian skeletal muscle cells, Bioelectromagnetics 20 (1999) 194-201; R.C. Lee, D.C. Gaylor, D. Bhatt, D.A. Israel, Role of cell membrane rupture in the pathogenesis of electrical trauma, J. Surg. Res. 44 (1988) 709-719; R.C. Lee, J.F. Burke, E.G. Cravalho (Eds.), Electrical Trauma: The Pathophysiology, Manifestations, and Clinical Management, Cambridge University Press, 1992; B.I. Tropea, R.C. Lee, Thermal injury kinetics in electrical trauma, J. Biomech. Engr. 114 (1992) 241-250; F. Despa, D.P. Orgill, J. Newalder, R.C Lee, The relative thermal stability of tissue macromolecules and cellular structure in burn injury, Burns 31 (2005) 568-577; T.A. Block, J.N. Aarsvold, K.L. Matthews II, R.A. Mintzer, L.P. River, M. Capelli-Schellpfeffer, R.L. Wollman, S. Tripathi, C.T. Chen, R.C. Lee, The 1995 Lindberg Award. Nonthermally mediated muscle injury and necrosis in electrical trauma, J. Burn Care and Rehabil. 16 (1995) 581-588; K. Miyake, P.L. McNeil, Mechanical injury and repair of cells, Crit. Care Med. 31 (2003) S496-S501; R.C. Lee, L.P. River, F.S. Pan, R.L. Wollmann, Surfactant-induced sealing of electropermeabilized skeletal muscle membranes in vivo, Proc. Natl. Acad. Sci. 89 (1992) 4524-4528; J.D. Marks, C.Y. Pan, T. Bushell, W. Cromie, R.C. Lee, Amphiphilic, tri-block copolymers provide potent membrane-targeted neuroprotection, FASEB J. 15 (2001) 1107-1109; B. Greenebaum, K. Blossfield, J. Hannig, C.S. Carrillo, M.A. Beckett, R.R. Weichselbaum, R.C. Lee, Poloxamer 188 prevents acute necrosis of adult skeletal muscle cells following high-dose irradiation, Burns 30 (2004) 539-547; G. Serbest, J. Horwitz, K. Barbee, The effect of poloxamer-188 on neuronal cell recovery from mechanical injury, J. Neurotrauma 22 (2005) 119-132]. The triblock copolymer surfactant Poloxamer 188 (P188) is known to increase the cell survival after membrane electroporation [R.C. Lee, L.P. River, F.S. Pan, R.L. Wollmann, Surfactant-induced sealing of electropermeabilized skeletal muscle membranes in vivo, Proc. Natl. Acad. Sci. 89 (1992) 4524-4528; Z. Ababneh, H. Beloeil, C.B. Berde, G. Gambarota, S.E. Maier, R.V. Mulkern, Biexponential parametrization of T2 and diffusion decay curves in a rat muscle edema model: Decay curve components and water compartments, Magn. Reson. Med. 54 (2005) 524-531]. Here, we use a rat hind-limb model of electroporation injury to determine if the intravenous administration of P188 improves the recovery of the muscle function. Rat hind-limbs received a sequence of either 0, 3, 6, 9, or 12 electrical current pulses (2 A, 4 ms duration, 10 s duty cycle). Magnetic resonance imaging (MRI) analysis, muscle water content and compound muscle action potential (CMAP) amplitudes were compared. Electroporation injury manifested edema formation and depression of the CMAP amplitudes. P188 (one bolus of 1 mg/ml of blood) was administrated 30 or 60 min after injury. Animals receiving P188 exhibited reduced tissue edema (p < 0.05) and increased CMAP amplitudes (p < 0.03). By comparison, treatment with 10 kDa neutral dextran, which produces similar serum osmotic effects as P188, had no effect on post-electroporation recovery. Noteworthy, the present results suggest that a single intravenous dose of P188 is effective to restore the structural integrity of damaged tissues with intact circulation.     

Poloxamer 188 Protects Neurons against Ischemia/Reperfusion Injury through Preserving Integrity of Cell Membranes and Blood Brain Barrier

Poloxamer 188 (P188), a multiblock copolymer surfactant, has been shown to protect against ischemic tissue injury of cardiac muscle, testes and skeletal muscle, but the mechanisms have not been fully understood. In this study, we explored whether P188 had a protective effect against cerebral ischemia/reperfusion injury and its underlying mechanisms. The in vivo results showed that P188 significantly reduced the infarct volume, ameliorated the brain edema and neurological symptoms 24 h after ischemia/reperfusion. In the long-term outcome study, P188 markedly alleviated brain atrophy and motor impairments and increased survival rate in 3 weeks of post stroke period. Additionally, P188 protected cultured hippucampal HT22 cells against oxygen–glucose deprivation and reoxygenation (OGD/R) injury. The ability in membrane sealing was assessed with two fluorescent membrane-impermeant dyes. The results showed that P188 treatment significantly reduced the PI-positive cells following ischemia/reperfusion injury and repaired the HT22 cell membrane rupture induced by Triton X-100. In addition, P188 inhibited ischemia/reperfusion-induced activation of matrix metalloproteinase (MMP)-9 and leakage of Evans blue. Therefore, the present study concludes that P188 can protect against cerebral ischemia/reperfusion injury, and the protection involves multi-mechanisms in addition to the membrane resealing.     

Book reviews

Book reviewed in this article:
P ractical D iagnosis of V iral I nfections (1992). Edited by G.J. Galasso, R.J. Whitley and T.C. Merigan.
M anual of C linical V irology (1992). By D.L. Wiedbrauk and S.L.G. Johnston.
C andidiasis : P athogenesis , D iagnosis and T reatment (2nd E dition ) (1993). Edited by G.P. Bodey.
F ungal D iseases of the L ung (2nd E dition ) (1993). Edited by G.A. Sarosi and S.F. Davies.
P robiotics : T he S cientific B asis (1992). Edited by R. Fuller.
T he S ulfate -R educing B acteria : C ontemporary P erspectives (1993). Edited by J.M. Odom and R. Singleton Jr.
D iagnosis of H uman V iruses by P olymerase C hain R eaction T echnology (1992). Edited by Y. Becker and G. Durai.
T he E cology of A quatic H yphomycetes (1992). Edited by F. Barlocher.     

Books

A ndrew R.J. (ed.) 1991. Neural and Behavioral Plasticity: the use of the domestic chick as a model
B eissinger , S.R. & S nyder , N.F.R. (eds) 1992. New World Parrots in Crisis: Solutions from Conservation Biology
B erthold , P. (ed.) 1991. Orientation in Birds
B urger , J. & G ochfeld . M. 1991. The Common Tern: its breeding biology and social behaviour. Pp. xvii + 413,121 figs incl. numerous black-and-white photographs, 59 text tables, 4 appendix tables. New York: Columbia University Press
D avis . L.S. & D arby , J.T. (eds) 1990. Penguin Biology
D ickinson , E.C., K ennedy , R.S. & P arkes , K.C. 1991. The Birds of the Philippines: an annotated check-list
D wenger .R. 1991. DasRebhuhn Perrfixperdix. 2nd edition
F inlayson , C. 1992. Birds of the Strait of Gibraltar
G osler , A. (ed.) 1991. The Hamlyn Photographic Guide to Birds of the World
G retton , A. 1991. The Ecology and Conservation of the Slender-billed Curlew
S mith , S.M. I 991. The Black-capped Chickadee: behavioural ecology and natural history. Pp. xi, 362. many figures and tables. Ithaca: Cornell University Press. $51.15 (hbk). ISBN 0–8014-2 382-1. $29.75 (pbk) ISBN 0–8014-9793-0.
S tap . D. 1991. A Parrot Without a Name: The search for the last unknown birds on earth.
T rodd , P., & K ramer D. 1991. The Birds of Bedfordshire
V aughan . R. 1992. In Search of Arctic Birds. Pp. xIII, 431, many monochrome photographs and drawings. London     

Function of the N-terminal calcium-binding sites in cardiac/slow troponin C assessed in fast skeletal muscle fibers

Fast skeletal troponin C (sTnC) has two low affinity Ca(2+)-binding sites (sites I and II), whereas in cardiac troponin C (cTnC) site I is inactive. By modifying the Ca2+ binding properties of sites I and II in cTnC it was demonstrated that binding of Ca2+ to an activated site I alone is not sufficient for triggering contraction in slow skeletal muscle fibers (Sweeney, H.L., Brito, R. M.M., Rosevear, P.R., and Putkey, J.A. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 9538-9542). However, a similar study using sTnC showed that Ca2+ binding to site I alone could partially activate force production in fast skeletal muscle fibers (Sheng, Z., Strauss, W.L., Francois, J.M., and Potter, J.D. (1990) J. Biol. Chem. 265, 21554-21560). The purpose of the current study was to examine the functional characteristics of modified cTnC derivatives in fast skeletal muscle fibers to assess whether or not either low affinity site can mediate force production when coupled to fast skeletal isoforms of troponin (Tn) I and TnT. Normal cTnC and sTnC were compared with engineered derivatives of cTnC having either both sites I and II active, or only site I active. In contrast to what is seen in slow muscle, binding of Ca2+ to site I alone recovered about 15-20% of the normal calcium-activated force and ATPase activity in skinned fast skeletal muscle fibers and myofibrils, respectively. This is most likely due to structural differences between TnI and/or TnT isoforms that allow for partial recognition and translation of the signal represented by binding Ca2+ to site I of TnC when associated with fast skeletal but not slow skeletal muscle.     

Books

Books reviewed in this article:
B aker . K. 1993. Identification Guide to European Non-passerines.
B arnard . C., G ilbert , F. & M c G regor
B askett , T.S., S ayre . M.W., T omlinson , R.E. & M irarchi .
B ezzel . E. 1993. Kompendium der Vögel Mitteleuropas.
B right , M. 1993. The Private Life of Birds.
C ook , M. 1992. The Birds of Moray and Nairn.
D avison . G.W.H. 1992. Birds of Mount Kinabalu. Borneo.
E rritzoe . J. 1993. The Buds of CITES and How to Identify Them.
F arner , D.S., K ing , J.R. & P arkes , K.C.
G ibbons , D.W., R eid , J.B. & C hapman . R.A. (eds). 1993. The New Atlas of Breeding Birds in Britain and Ireland.
H illman , J.C.
H uxley . E.
J ackson . C.E. 1993. Great Bird Paintings of the World.
J ohnsgard . P.A. 1993. Cormorants, Darters and Pelicans of the World.
M adge . S. & B urn , H. 1994. Crows and Jays. A Guide to the Crows, Jays and Magpies of the World.
N icolai . B. (ed.).
P ower , D.M. (ed.).
P riklonskiy . S.G. (ed.).
R alph . R. 1993. William MacGillivray.
R obinson , D. & C hapman , A.
S harp . P.J. 1993. Avian Endocrinology.
S mith , K.W., D fe , C.W., F earnside . J.D., F letcher , E.W. & S mith , R.N.
S olomon . D. & W illiams , J.
S ørensen , S., B loch . D. & L angvad . S.
Z immerman , J.L.     

Book reviews

Book reviewed in this article:
N eutralization of A nimal V iruses (1993). By N.J. Dimmock.
Bacillus subtilis and O ther G ram -P ositive B acteria : B iochemistry , P hysiology and M olecular G enetics (1993).
C hilled F oods : A C omprehensive G uide (1992). Edited by C. Dennis and M. Stringer.
M edical M icrobiology (1992). Edited by D. Greenwood, R. Slack and J. Peutherer.
B acteriocins of L actic A cid B acteria (1993). Edited by D.G. Hoover and L.R. Steenson.
Bacillus thuringiensis , an E nvironmental B iopesticide : T heory and P ractice (1993). Edited by P.F. Entwistle, J.S. Cory, M.J. Bailey and S. Higgs.
P ediatric I nfectious D isease (1993). Edited by D. Engelhard, M.I. Marks and D. Branski.     

The hereditary hemochromatosis protein, HFE, specifically regulates transferrin-mediated iron uptake in HeLa cells

HFE is the protein product of the gene mutated in the autosomal recessive disease hereditary hemochromatosis (Feder, J. N., Gnirke, A., Thomas, W., Tsuchihashi, Z., Ruddy, D. A., Basava, A., Dormishian, F., Domingo, R. J., Ellis, M. C., Fullan, A., Hinton, L. M., Jones, N. L., Kimmel, B. E., Kronmal, G. S., Lauer, P., Lee, V. K., Loeb, D. B., Mapa, F. A., McClelland, E., Meyer, N. C., Mintier, G. A., Moeller, N., Moore, T., Morikang, E., Prasss, C. E., Quintana, L., Starnes, S. M., Schatzman, R. C., Brunke, K. J., Drayna, D. T., Risch, N. J., Bacon, B. R., and Wolff, R. R. (1996) Nat. Genet. 13, 399-408). At the cell surface, HFE complexes with transferrin receptor (TfR), increasing the dissociation constant of transferrin (Tf) for its receptor 10-fold (Gross, C. N., Irrinki, A., Feder, J. N., and Enns, C. A. (1998) J. Biol. Chem. 273, 22068-22074; Feder, J. N., Penny, D. M., Irrinki, A., Lee, V. K., Lebron, J. A., Watson, N. , Tsuchihashi, Z., Sigal, E., Bjorkman, P. J., and Schatzman, R. C. (1998) Proc. Natl. Acad. Sci. U S A 95, 1472-1477). HFE does not remain at the cell surface, but traffics with TfR to Tf-positive internal compartments (Gross et al., 1998). Using a HeLa cell line in which the expression of HFE is controlled by tetracycline, we show that the expression of HFE reduces 55Fe uptake from Tf by 33% but does not affect the endocytic or exocytic rates of TfR cycling. Therefore, HFE appears to reduce cellular acquisition of iron from Tf within endocytic compartments. HFE specifically reduces iron uptake from Tf, as non-Tf-mediated iron uptake from Fe-nitrilotriacetic acid is not altered. These results explain the decreased ferritin levels seen in our HeLa cell system and demonstrate the specific control of HFE over the Tf-mediated pathway of iron uptake. These results also have implications for the understanding of cellular iron homeostasis in organs such as the liver, pancreas, heart, and spleen that are iron loaded in hereditary hemochromatotic individuals lacking functional HFE.     

Calculation of free-Mg2+ concentration in adenosine 5'-triphosphate containing solutions in vitro and in vivo

We have attempted to resolve the differences between the levels of free Mg2+ in muscle calculated by Wu et al. [Wu, S. T., Pieper, G. M., Salhany, J. M., & Eliot, R. S. (1981) Biochemistry 20, 7399-7403] (2.5 mM in guinea pig heart) and by Gupta and Moore [Gupta, R. K., & Moore, R. D. (1980) J. Biol. Chem. 255, 3987-3993] (0.6 mM in frog skeletal muscle) on the basis of substantially identical measurements by 31P NMR of the phosphate peaks in the spectrum of MgATP2-. The differences depend on the methods of calculation, including which reactions in which multiple equilibria are being considered. Biochemists and physical chemists customarily use different working definitions of the stability constant for MgATP2- in particular. Wu et al. used in their calculations, without reconciliation, methods involving three different operational definitions of the chelation equilibria involved. An algorithm for calculating Mg2+ and total ATP, which can be carried out with a hand calculator, is described here. With it, we calculated Mg2+ levels that agree with those determined by Gupta et al. [Gupta, R. K., Benkovic, J. L., & Rose, Z. B. (1978) J. Biol. Chem. 253, 6165-6171] with their in vitro systems. We therefore agree with the finding of Gupta and Moore that the Mg2+ level in skeletal and cardiac muscle is 0.6 mM.     

Book Reviews

Book reviewed in this article:
L egionella : C urrent S tatus and E merging P erspectives (1993). Edited by J.M. Barbaree, R.F. Breiman and A.P. Dufour.
Pseudomonas: M olecular B iology and B iotechnology (1992). Edited by E. Galli, S. Silver and B. Witholt.
A dvances in B iochemical E ngineering / B iotechnology 45 (1992). Edited by A. Fiechter.
A dvances in M icrobial E cology (1993). Edited by K.C. Marshall.
T he B iology of H alophilic B acteria (1993). Edited by R.H. Vreeland and L.I. Hochstein.
B akterienviren (1992). By S. Klaus, D. Krüger and J. Meyer.     

Books

Book reviewed in this article: Berndt , R.K. & Busche , G. (eds). 1993. Vogelwelt Schleswig-Hoisteins. Band 4: Entenvagel I1 (Kolbenente-Ruderente). Bildstein . K.L. 1993. White Ibis, wetland wanderer. Birkan , M., Pm , G.R., Aebischher , N.J. & Dowell , S.D. (eds). 1992. Perdix VI. First International Symposium on Partridges, Quails and Francolins. Gibier Faune Sauvage. Birkhead , T. 1993. Great Auk Islands. A field biologist in the Arctic. Butler . D. & Merton , D. 1992. The Black Robin: Saving the world's most endangered bird. Clancey , P.A. 1992. Kingfishers of Sub-Saharan Africa. Standard edition. Committee on the Scientific Bases for the Preservation of the Hawaiian Crow . 1992. The Scientific Bases for the Preservation of the Hawaiian Crow. Cramp , S. & Perrins , C.M. (eds). 1993. Handbook of the Birds of Europe, the Middle East and North Africa: The Birds of the Western Palearctic. Sonograms reprinted from Volume VII. Flycatchers to Shrikes. De Blieu . J. 1991. Meant to be Wild. The Struggle to Save Endangered Species through Captive Breeding. Einarsson , P. 1991. Guide to the Birds Iceland. A Practical Handbook for Identification. Eldredge , N. 1992. Systematics, Ecology and the Biodiversity Crisis. Gosler , A. 1993. The Great Tit. Hammond , N. & Pearson . B. 1993. Birds of Prey. Knystautas , A. 1993. Birds of Russia. Lack , P. & Ferguson . D. (eds). 1993. The Birds of Buckinghamshire. Lindsey , T.R. 1992. Encylopaedia of Australian Animals. Birds. Mac Kinnon , J. & Phillipps , K. 1993. A Field Guide to the Birds of Borneo, Sumatra, Java. and Bali. Mc Farlane . R.W. 1992. A Stillness in the Pines. The Ratcliffe , D. 1993. The Peregrine Faicon. 2nd ed. Shrubb . M. 1993. The Kestrel. Sinclair . I., Hockey . P., Tarboton , W., Hayman . P. & Arlott , N. 1993. Illustrated Guide to the Birds of Southern Africa. Andrews , J. & Carter . S. (eds). 1993. Britain's Birds in 1990–91: The conservation and monitoring review. Bond , J.T & Hume . K. 1993. Birds: An artist's view. Carter , R.M. 1993. Finding Birds in South Carolina. Choremi . J., Choulis . D. & Spnhakis , V. 1993. The Birds of the Island of Chios Greece. Dennis , N. & Tarboton . W. 1993. Waterbirds. Birds of Southern Africa's Wetlands. Duckworth . D., Genoways , H.H. & Rose . C.L. 1991. Preserving Natural Science Collections: Chronicle of our environmental heritage. Epple , W., Holzinger , J. & Schmid , G. (cds). 1992. Artenschutzsym-posiuni Wendehals. Lambert , F.A. 1993. The Status of and Trade in North Moluccan Parrots with Particular Emphasis on Cacatua alba. Lorius garrulus and Eos squamatn. Moser . M. & van Vessem , J. (eds). 1993. Wetland and Waterfowl Conservation in South and West Asia. Olney . P.J.S. & Ellis , P. (eds). 1992. International Zoo Yearbook. Perrins , C.M., Le Breton , J-D. & Hirons , G.J.M. 1993. Bird Population Studies: Relevance to conservation and management. Ruge . K., Heidinger , C. & Havelka , P. (eds). 1993. Artenschutzsym-posium Spechte. ?tastny , K. & Bej?ek , V. (eds). 1990. Bird Census and Atlas Studies. Taylor . M. & Canberra Ornithologists Grow . 1992. Birds of the Australian Capital Territory, an Atlas. Walraven . E. 1992. Rescue and Rehabilitation of Oiled Birds: Field manual. Wilson , R.T. (ed.). 1993. Birds and the African Environment. Proceedings of the Eighth Pan–African Ornithological Congress. Won , P. 1993. [A Field Guide to the Birds of Korea]. World Conservation Centre . 1993. World Checklist of Threatened Birds. Jeffery Boswall     

Also Received

Books Reviewed in this article: Barker , R.D. & Vestjens , W.J.M. 1991. The Food of Australian Birds. Beatty , J. 1992. Sula: the seabird hunters of Lewis. Bruun , B., Delin , H. & Svensson , L. 1992. Birds of Britain and Europe. Cowell . S. Adatia , R. & Gibson . B. 1992. Who's Who in the Environment—England. Dimentman , C., Bromley . H.J. & Por , F.D. 1992. Lake Hula: reconstruction of the fauna and hydrobiology of a lost lake. Eagle , R. 1991. Seton Gordon, the Life and Times of a Highland Gentleman. Ford . E. 1992. Falconry: art and practice. Foschi , U.F. & Gellini , S. 1992. Avifauna e Ambiente in Provincia di Fork le comunita di uccelli come indicatori ecologici. Guest , J.P. Elphick , D., Hunter . J.S.A. & Norman . D. 1992. The Breeding Bird Atlas of Cheshire and Wirral. Hayes , L.B. & Hayes , M.L. 1987. Raising Game Birds. Hayes , L. B. 1992. The Chinese Painted Quail, ‘the Button Quail’: their breeding and care Hollands , D. 1991. Birds of the Night, Owls, Frogmouths and Nightjars of Australia. Ironmonger . J. 1992. The Good Zoo Guide. Kiew , R. (ed.) 1991. the State of Nature Conservation in Malaysia. La Bastille , A. 1990. Mama Poc: an ecologist's account of the extinction of a species. Lambert , M. 1992. Birds by Colour. Layton . L. 1991. Songbirds in Singapore: the growth of a pastime. Liversidge , R. 1991. The Birds around Us. Love , J.A. 1989. Eagles. Mellanby , K. 1992. The DDT Story. Pp. 112. Farnham: British Crop Protection Council. Newman , K., Johnston -Stewart , N. & Medland , B. 1992. Birds of Malawi. A supplement to Newman's Birds of Southern Africa. Ogilvie , M. 1992. The Birds of Islay: including when and where to find them. Orr , O.H. 1992. Saving American Birds: T. Gilbert Pearson and the founding movement of the Audubon Society. Ortiz Crespo , F., Greenfield , P.J. & Matheus , J.C. 1990. Aves del Ecuador Continente y Archipielago de Galápagos/Birds of Ecuador Paine , J.R. & World Conservation Monitoring Centre. 1991. IUCN Directory of Protected Areas in Oceania. Petersen , M.R., Weir , D.N. & Dick , M.H. 1991. Birds of Kilbuck and Ahklun Mountain Region, Alaska. Riddle , G. 1991. Seasons with the Kestrel. Simpson , M.B., Jr. 1992. Birds of the Blue Ridge Mountains. Stallcup , R. 1990. Ocean Birds of the Nearshore Pacific. Strange , I.J. 1992. A Field Guide to the Wildlife of the Falkland Islands and South Georgia. Trollope , J. 1992. Seed-eating Birds, Their Care and Breeding: finches and allied species—doves, quail and hemipodes. Village , A. 1992. Falcons.     

Ca2+ Binding/Permeation via Calcium Channel,CaV1.1, Regulates the Intracellular Distribution of the Fatty Acid Transport Protein,CD36, and Fatty Acid Metabolism

Ca²⁺ permeation and/or binding to the skeletal muscle L-type Ca²⁺ channel (Ca_V1.1) facilitates activation of Ca²⁺/calmodulin kinase type II (CaMKII) and Ca²⁺ store refilling to reduce muscle fatigue and atrophy (Lee, C. S., Dagnino-Acosta, A., Yarotskyy, V., Hanna, A., Lyfenko, A., Knoblauch, M., Georgiou, D. K., Poché, R. A., Swank, M. W., Long, C., Ismailov, I. I., Lanner, J., Tran, T., Dong, K., Rodney, G. G., Dickinson, M. E., Beeton, C., Zhang, P., Dirksen, R. T., and Hamilton, S. L. (2015) Skelet. Muscle 5, 4). Mice with a mutation (E1014K) in the Cacna1s (α₁ subunit of Ca_V1.1) gene that abolishes Ca²⁺ binding within the Ca_V1.1 pore gain more body weight and fat on a chow diet than control mice, without changes in food intake or activity, suggesting that Ca_V1.1-mediated CaMKII activation impacts muscle energy expenditure. We delineate a pathway (Ca_v1.1→ CaMKII→ NOS) in normal skeletal muscle that regulates the intracellular distribution of the fatty acid transport protein, CD36, altering fatty acid metabolism. The consequences of blocking this pathway are decreased mitochondrial β-oxidation and decreased energy expenditure. This study delineates a previously uncharacterized Ca_V1.1-mediated pathway that regulates energy utilization in skeletal muscle.     

A 1H NMR study of a ternary peptide complex that mimics the interaction between troponin C and troponin I.

The troponin I peptide N alpha-acetyl TnI (104-115) amide (TnIp) represents the minimum sequence necessary for inhibition of actomyosin ATPase activity of skeletal muscle (Talbot, J.A. & Hodges, R.S. 1981, J. Biol. Chem. 256, 2798-3802; Van Eyk, J.E. & Hodges, R.S., 1988, J. Biol. Chem. 263, 1726-1732; Van Eyk, J.E., Kay, C.M., & Hodges, R.S., 1991, Biochemistry 30, 9974-9981). In this study, we have used 1H NMR spectroscopy to compare the binding of this inhibitory TnI peptide to a synthetic peptide heterodimer representing site III and site IV of the C-terminal domain of troponin C (TnC) and to calcium-saturated skeletal TnC. The residues whose 1H NMR chemical shifts are perturbed upon TnIp binding are the same in both the site III/site IV heterodimer and TnC. These residues include F102, I104, F112, I113, I121, I149, D150, F151, and F154, which are all found in the C-terminal domain hydrophobic pocket and antiparallel beta-sheet region of the synthetic site III/site IV heterodimer and of TnC. Further, the affinity of TnIp binding to the heterodimer (Kd = 192 +/- 37 microM) was found to be similar to TnIp binding to TnC (48 +/- 18 microM [Campbell, A.P., Cachia, P.J., & Sykes, B.D., 1991, Biochem. Cell Biol. 69, 674-681]). The results indicate that binding of the inhibitory region of TnI is primarily to the C-terminal domain of TnC. The results also indicate how well the synthetic peptide heterodimer mimics the C-terminal domain of TnC in structure and functional interactions.     

Graphics for Statistics and Data Analysis with R by KEEN,K. J.

Graphics for Statistics and Data Analysis with R (K. J. Keen) Michael Friendly Hidden Markov Models for Time Series: An Introduction Using R (W. Zucchini and I. L. MacDonald) Peter Guttorp Bayesian Adaptive Methods for Clinical Trials (S. M. Berry, B. P. Carlin, J. J. Lee, J. J. and P. Muller) Say Beng Tan SAS and R Data Management, Statistical Analysis, and Graphics (K. Kleinman and N. Horton) Juan P. Steibel Numerical Analysis for Statisticians, 2nd edition (K. Lange) Maria Rizzo Statistical Methods for Disease Clustering (T. Tango) Lance A. Waller Brief Reports by the Editor Survival Analysis Using SAS: A Practical Guide (P. D. Allison) Design and Analysis of Quality of Life Studies in Clinical Trials (D. L. Fairclough) Nonparametric Statistical Inference (J. D. Gibbons and S. Chakraborti) Stochastic Processes: An Introduction (P. W Jones and P. Smith)
     

Interaction of the heavy chain of gizzard myosin heads with skeletal F-actin

To probe the molecular properties of the actin recognition site on the smooth muscle myosin heavy chain, the rigor complexes between skeletal F-actin and chicken gizzard myosin subfragments 1 (S1) were investigated by limited proteolysis and by chemical cross-linking with 1-ethyl-3-[3-(dimethyl-amino)propyl]carbodiimide. Earlier, these approaches were used to analyze the actin site on the skeletal muscle myosin heads [Mornet, D., Bertrand, R., Pantel, P., Audemard, E., & Kassab, R. (1981) Biochemistry 20, 2110-2120; Labbé, J.P., Mornet, D., Roseau, G., & Kassab, R. (1982) Biochemistry 21, 6897-6902]. In contrast to the case of the skeletal S1, the cleavage with trypsin or papain of the sensitive COOH-terminal 50K-26K junction of the head heavy chain had no effect on the actin-stimulated Mg2+-ATPase activity of the smooth S1. Moreover, actin binding had no significant influence on the proteolysis at this site whereas it abolished the scission of the skeletal S1 heavy chain. The COOH-terminal 26K segment of the smooth papain S1 heavy chain was converted by trypsin into a 25K peptide derivative, but it remained intact in the actin-S1 complex. A single actin monomer was cross-linked with the carbodiimide reagent to the intact 97K heavy chain of the smooth papain S1. Experiments performed on the complexes between F-actin and the fragmented S1 indicated that the site of cross-linking resides within the COOH-terminal 25K fragment of the S1 heavy chain. Thus, for both the striated and smooth muscle myosins, this region appears to be in contact with F-actin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reviews

Book reviewed in this article:
Plant Molecular Biology. Molecular Genetic Analysis of Plant Development and Metabolism. Ed. by G loria C oruzzi & P ere P uigdomégnech
Vacuum Methods in Electron Microscopy. By W. C. B igelow . Practical Methods in Electron Microscopy. Vol 15. Series Editor: Audrey M. G lauert .
The Fungi. By M ichael J. C arlile & S arah C. W atkinson .
Aspects of Tropical Mycology. Symposium of the British Mycological Society held at the University of Liverpool, April 1992. Edited by S. I saac , J. C. F rankland , R. W atling & A. J. S. W halley .
Belalong, A Tropical Rainforest. By T he E arl O f C ranbrook & D avid S. E dwards .
Ecology and Management of Invasive Riverside Plants. Ed. by L. C. D e W aal , L. E. C hild , P. M. W ade & J. H. B rock