The Biochemical Basis of Muscle Contraction1
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The Myosin Interacting-Heads Motif Present in Live Tarantula Muscle Explains Tetanic and Posttetanic INAUGURAL ARTICLE Phosphorylation Mechanisms
The myosin interacting-heads motif present in live tarantula muscle explains tetanic and posttetanic INAUGURAL ARTICLE phosphorylation mechanisms Raúl Padróna,1,2, Weikang Mab,1, Sebastian Duno-Mirandac,3, Natalia Koubassovad, Kyoung Hwan Leea,4, Antonio Pintoc, Lorenzo Alamoc, Pura Bolañose, Andrey Tsaturyand, Thomas Irvingb, and Roger Craiga aDivision of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655; bBiophysics Collaborative Access Team, Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616; cCentro de Biología Estructural, Instituto Venezolano de Investigaciones Científicas, Caracas 1020A, Venezuela; dInstitute of Mechanics, Moscow State University, 119992 Moscow, Russia; and eCentro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas 1020A, Venezuela This contribution is part of the special series of Inaugural Articles by members of the National Academy of Sciences elected in 2018. Contributed by Raúl Padrón, April 7, 2020 (sent for review December 6, 2019; reviewed by H. Lee Sweeney and Rene Vandenboom) Striated muscle contraction involves sliding of actin thin filaments frozen-hydrated tarantula thick filaments showed that the helices along myosin thick filaments, controlled by calcium through thin of heads on the filaments were formed by a two-headed assem- filament activation. In relaxed muscle, the two heads of myosin blage that we called the myosin interacting-heads motif (IHM) interact with each other on the filament surface to form the (8, 9), formed by the interaction of a blocked head (BH) and a interacting-heads motif (IHM). A key question is how both heads free head (FH) (10) with the subfragment-2 (8) (Fig. -
Characterization of Cecal Smooth Muscle Contraction in Laying Hens
veterinary sciences Communication Characterization of Cecal Smooth Muscle Contraction in Laying Hens Katrin Röhm 1, Martin Diener 2 , Korinna Huber 1 and Jana Seifert 1,* 1 Institute of Animal Science, University of Hohenheim, 70593 Stuttgart, Germany; [email protected] (K.R.); [email protected] (K.H.) 2 Institute of Veterinary Physiology and Biochemistry, Justus-Liebig University, 35392 Gießen, Germany; [email protected] * Correspondence: [email protected] Abstract: The ceca play an important role in the physiology of the gastrointestinal tract in chickens. Nevertheless, there is a gap of knowledge regarding the functionality of the ceca in poultry, especially with respect to physiological cecal smooth muscle contraction. The aim of the current study is the ex vivo characterization of cecal smooth muscle contraction in laying hens. Muscle strips of circular cecal smooth muscle from eleven hens are prepared to investigate their contraction ex vivo. Contraction is detected using an isometric force transducer, determining its frequency, height and intensity. Spontaneous contraction of the chicken cecal smooth muscle and the influence of buffers (calcium-free buffer and potassium-enriched buffer) and drugs (carbachol, nitroprusside, isoprenaline and Verapamil) affecting smooth muscle contraction at different levels are characterized. A decrease in smooth muscle contraction is observed when a calcium-free buffer is used. Carbachol causes an increase in smooth muscle contraction, whereas atropine inhibits contraction. Nitroprusside, isoprenaline and Verapamil result in a depression of smooth muscle contraction. In conclusion, the present results confirm a similar contraction behavior of cecal smooth muscles in laying hens as Citation: Röhm, K.; Diener, M.; shown previously in other species. -
Back-To-Basics: the Intricacies of Muscle Contraction
Back-to- MIOTA Basics: The CONFERENCE OCTOBER 11, Intricacies 2019 CHERI RAMIREZ, MS, of Muscle OTRL Contraction OBJECTIVES: 1.Review the anatomical structure of a skeletal muscle. 2.Review and understand the process and relationship between skeletal muscle contraction with the vital components of the nervous system, endocrine system, and skeletal system. 3.Review the basic similarities and differences between skeletal muscle tissue, smooth muscle tissue, and cardiac muscle tissue. 4.Review the names, locations, origins, and insertions of the skeletal muscles found in the human body. 5.Apply the information learned to enhance clinical practice and understanding of the intricacies and complexity of the skeletal muscle system. 6.Apply the information learned to further educate clients on the importance of skeletal muscle movement, posture, and coordination in the process of rehabilitation, healing, and functional return. 1. Epithelial Four Basic Tissue Categories 2. Muscle 3. Nervous 4. Connective A. Loose Connective B. Bone C. Cartilage D. Blood Introduction There are 3 types of muscle tissue in the muscular system: . Skeletal muscle: Attached to bones of skeleton. Voluntary. Striated. Tubular shape. Cardiac muscle: Makes up most of the wall of the heart. Involuntary. Striated with intercalated discs. Branched shape. Smooth muscle: Found in walls of internal organs and walls of vascular system. Involuntary. Non-striated. Spindle shape. 4 Structure of a Skeletal Muscle Skeletal Muscles: Skeletal muscles are composed of: • Skeletal muscle tissue • Nervous tissue • Blood • Connective tissues 5 Connective Tissue Coverings Connective tissue coverings over skeletal muscles: .Fascia .Tendons .Aponeuroses 6 Fascia: Definition: Layers of dense connective tissue that separates muscle from adjacent muscles, by surrounding each muscle belly. -
Muscle Physiology Dr
Muscle Physiology Dr. Ebneshahidi Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Skeletal Muscle Figure 9.2 (a) Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the muscular system . 1. Locomotion . 2. Vasoconstriction and vasodilatation- constriction and dilation of blood vessel Walls are the results of smooth muscle contraction. 3. Peristalsis – wavelike motion along the digestive tract is produced by the Smooth muscle. 4. Cardiac motion . 5. Posture maintenance- contraction of skeletal muscles maintains body posture and muscle tone. 6. Heat generation – about 75% of ATP energy used in muscle contraction is released as heat. Copyright. © 2004 Pearson Education, Inc., publishing as Benjamin Cummings . Striation: only present in skeletal and cardiac muscles. Absent in smooth muscle. Nucleus: smooth and cardiac muscles are uninculcated (one nucleus per cell), skeletal muscle is multinucleated (several nuclei per cell ). Transverse tubule ( T tubule ): well developed in skeletal and cardiac muscles to transport calcium. Absent in smooth muscle. Intercalated disk: specialized intercellular junction that only occurs in cardiac muscle. Control: skeletal muscle is always under voluntary control‚ with some exceptions ( the tongue and pili arrector muscles in the dermis). smooth and cardiac muscles are under involuntary control. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Innervation: motor unit . a) a motor nerve and a myofibril from a neuromuscular junction where gap (called synapse) occurs between the two structures. at the end of motor nerve‚ neurotransmitter (i.e. acetylcholine) is stored in synaptic vesicles which will release the neurotransmitter using exocytosis upon the stimulation of a nerve impulse. Across the synapse the surface the of myofibril contains receptors that can bind with the neurotransmitter. -
Genome-Wide Identification, Characterization and Expression
G C A T T A C G G C A T genes Article Genome-Wide Identification, Characterization and Expression Profiling of myosin Family Genes in Sebastes schlegelii Chaofan Jin 1, Mengya Wang 1,2, Weihao Song 1 , Xiangfu Kong 1, Fengyan Zhang 1, Quanqi Zhang 1,2,3 and Yan He 1,2,* 1 MOE Key Laboratory of Molecular Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; [email protected] (C.J.); [email protected] (M.W.); [email protected] (W.S.); [email protected] (X.K.); [email protected] (F.Z.); [email protected] (Q.Z.) 2 Laboratory of Tropical Marine Germplasm Resources and Breeding Engineering, Sanya Oceanographic Institution, Ocean University of China, Sanya 572000, China 3 Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China * Correspondence: [email protected]; Tel.: +86-0532-82031986 Abstract: Myosins are important eukaryotic motor proteins that bind actin and utilize the energy of ATP hydrolysis to perform a broad range of functions such as muscle contraction, cell migration, cytokinesis, and intracellular trafficking. However, the characterization and function of myosin is poorly studied in teleost fish. In this study, we identified 60 myosin family genes in a marine teleost, black rockfish (Sebastes schlegelii), and further characterized their expression patterns. myosin showed divergent expression patterns in adult tissues, indicating they are involved in different types and Citation: Jin, C.; Wang, M.; Song, W.; compositions of muscle fibers. Among 12 subfamilies, S. schlegelii myo2 subfamily was significantly Kong, X.; Zhang, F.; Zhang, Q.; He, Y. -
Acanthamoeba Is an Evolutionary Ancestor of Macrophages: a Myth Or Reality? Ruqaiyyah Siddiqui Aga Khan University
eCommons@AKU Department of Biological & Biomedical Sciences Medical College, Pakistan February 2012 Acanthamoeba is an evolutionary ancestor of macrophages: A myth or reality? Ruqaiyyah Siddiqui Aga Khan University Naveed Ahmed Khan Aga Khan University Follow this and additional works at: http://ecommons.aku.edu/pakistan_fhs_mc_bbs Part of the Biochemistry Commons Recommended Citation Siddiqui, R., Khan, N. (2012). Acanthamoeba is an evolutionary ancestor of macrophages: A myth or reality?. Experimental Parasitology, 130(2), 95-97. Available at: http://ecommons.aku.edu/pakistan_fhs_mc_bbs/16 Experimental Parasitology 130 (2012) 95–97 Contents lists available at SciVerse ScienceDirect Experimental Parasitology journal homepage: www.elsevier.com/locate/yexpr Minireview Acanthamoeba is an evolutionary ancestor of macrophages: A myth or reality? ⇑ Ruqaiyyah Siddiqui a, Naveed Ahmed Khan a,b, a Aga Khan University, Stadium Road, Karachi, Pakistan b School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, England, UK article info abstract Article history: Given the remarkable similarities in cellular structure (morphological and ultra-structural features), Received 26 October 2011 molecular motility, biochemical physiology, ability to capture prey by phagocytosis and interactions with Received in revised form 17 November 2011 microbial pathogens, here we pose the question whether Acanthamoeba and macrophages are evolution- Accepted 19 November 2011 ary related. This is discussed in the light of evolution and functional aspects such as the astonishing Available online 28 November 2011 resemblance of many bacteria to infect and multiply inside human macrophages and amoebae in analo- gous ways. Further debate and studies will determine if Acanthamoeba is an evolutionary ancestor of Keywords: macrophages. Is this a myth or reality? Acanthamoeba Ó 2011 Elsevier Inc. -
Primary Human Chondrocytes Respond to Compression with Phosphoproteomic Signatures That Include Microtubule Activation ⇑ Donald L
Journal of Biomechanics 97 (2019) 109367 Contents lists available at ScienceDirect Journal of Biomechanics journal homepage: www.elsevier.com/locate/jbiomech www.JBiomech.com Primary human chondrocytes respond to compression with phosphoproteomic signatures that include microtubule activation ⇑ Donald L. Zignego a, Jonathan K. Hilmer b, Brian Bothner b, William J. Schell a, Ronald K. June a, a Department of Mechanical & Industrial Engineering, Montana State University, United States b Department of Chemistry and Biochemistry, Montana State University, United States article info abstract Article history: Chondrocytes are responsible for maintaining the cartilage that helps joints bear load and move Accepted 22 September 2019 smoothly. These cells typically respond to physiological compression with pathways consistent with matrix synthesis, and chondrocyte mechanotransduction is essential for homeostasis. In osteoarthritis (OA), chondrocyte mechanotransduction appears to be dysregulated, yet the mechanisms remain poorly Keywords: understood. The objective of this study is to document the phosphoproteomic responses of primary Chondrocyte biology osteoarthritic chondrocytes to physiological sinusoidal compression. We show that OA chondrocytes Cartilage biomechanics respond to physiological compression by first activating proteins consistent with cytoskeletal remodeling Mechanobiology and decreased transcription, and then later activating proteins for transcription. These results show that Mechanotransduction Cartilage repair several microtubule-related proteins respond to compression. Our results demonstrate that compression Osteoarthritis is a relevant physiological stimulus for osteoarthritic chondrocytes. Future analyses may build on these results to find differences in compression-induced phosphoproteins between normal and OA cells that lead to druggable targets to restore homeostasis to diseased joints. Ó 2019 Elsevier Ltd. All rights reserved. 1. Introduction (Jaalouk and Lammerding, 2009). -
STRUCTURE of PARAMECIUM Dr Poonam Kumari Dept of Zoology (BSC PART I PAPER I)
STRUCTURE OF PARAMECIUM Dr Poonam kumari Dept Of Zoology (BSC PART I PAPER I) It is a single-celled eukaryote belonging to kingdom Protista and is a well-known genus of ciliate protozoa. Paramecium is a unicellular organism with a shape resembling the sole of a shoe. It ranges from 50 to 300um in size which varies from species to species. It is mostly found in a freshwater environment. Structure (Morphology) (1) Size: Paramecium is an microscopic, a cellular elongated organism visible to the baked eye as a whitish or greyish spot. The size varies in different species, in length from 80 to 350 and diameter 170 to 290 . The greatest diameter of the cylindrical body is about two third of its entire length. Usually the individuals of the same species may show minor morphological and physiological differences. (2) Shape: Paramecium is a slipper shaped, cigar shaped, or spindle shaped animalcule. Its shape is usually constant and a symmetrical, because slipper like shape. The body is elongated, blunt and rounded at the anterior end and somewhat pointed of the posterior end. In cross section it is circular with greatest diameter behind the centre of body. The anterior half of the body is slightly twisted. The body is distinguished into an oral or ventral surface and an aboral or dorsal surface. The structure is more complicated due to the development of certain organelles in the acellular body. (3) Oral groove: The ventral surface of body bears a prominent, oblique and shallow depression is called oral groove, it arise from the middle of body and extends to the left side of anterior end. -
EE Just's "Independent Irritability"
ESSAY Molecular Reproduction & Development 76:966–974 (2009) E.E. Just’s ‘‘Independent Irritability’’ Revisited: The Activated Egg as Excitable Soft Matter STUART A. NEWMAN* Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York SUMMARY Ernest Everett Just’s experimental work on post-fertilization events in invertebrate eggs led him to posit a dynamic and directive role for the zygotic ‘‘ectoplasm’’ (cortical Just was correct in his estimation cytoplasm), in subsequent development. His perspective was neglected during the of the ‘‘informational’’ role of the years that followed his early death not only because of his well-documented margina- ectoplasm’s dynamics. lization as an African-American in U.S. science, but because his ideas were at odds with the growing gene-centrism of developmental biology in the latter half of the 20th century. This essay reviews experimental work that shows that the egg cortex in many animal groups is a chemically and mechanically active medium that sustains both spatiotemporal calcium ion transients and periodic deformations in the time leading up * Corresponding author: to cleavage. These wave phenomena are seen to play regulatory roles in germ plasm Department of Cell Biology and localization and gene expression, and influence the reliability and success of devel- Anatomy opmental outcomes. Just resisted vitalistic explanations for the active processes he New York Medical College Basic Science Building observed and inferred regarding the egg cortical cytoplasm, but recognized that the Valhalla, NY 10595. physics and chemistry of his time were inadequate to account for these phenomena E-mail: [email protected] and anticipated that expansions of these fields would be necessary to explain them. -
Cytoskeleton and Cell Motility
Cytoskeleton and Cell Motility 1. (28 pts) Amoeba proteus, a single-celled eukaryote, moves by means of psudopods attaching to and detaching from the substratum. Locomotion seems to be correlated with the forward flow of fluid cytoplasm (endoplasm) into an advancing pseudopod through a surrounding, gel-like ectoplasmic tube. The ectoplasm forms at the pseudopodial tip in a region called the Fountain Zone. As the amoeba advances the ectoplasmic tube “liquifies” at the posterior end to form endoplasm. These features are illustrated in the figure below. Both locomotion and cytoplasmic streaming are inhibited by cytochalasin B. Consider everything you’ve learned so far and answer all the following questions. A. (4 pts) When amoeba undergoes cell division, it stops streaming and rounds up into a spherical cell. Describe how this change in shape and behavior comes about and why it might be a necessary precondition for division. B. (6 pts) Briefly describe how cytoplasmic streaming is most likely organized and generated at the cellular and molecular levels. C. (5 pts) Briefly describe an additional experiment or observation that would test your hypothesis and indicate clearly what the results would show. CCM - 1 Cytoskeleton and Cell Motility D. (8 pts) Describe clearly, with the aid of a well-labeled diagram, how streaming within a pseudopod could result in movement of the amoeba across the substratum. E. (5 pts) Describe how your streaming mechanism might be regulated such that the amoeba might change its streaming pattern to form phagocytic pseudopods around a ciliate it had touched. Now evaluate some past answers to these questions, in light of your own essays. -
Structure and Development of the Egg of the Glossiphoniid Leech Theromyzon Rude: Characterization of Developmental Stages and Structure of the Early Uncleaved Egg
Development 100, 211-225 (1987) 211 Printed in Great Britain © The Company of Biologists Limited 1987 Structure and development of the egg of the glossiphoniid leech Theromyzon rude: characterization of developmental stages and structure of the early uncleaved egg JUAN FERNANDEZ, NANCY OLEA and CECILIA MATTE Departamento de Biologia, Facultad de Ciendas, Untversidad de Chile, Casilla 653, Santiago, Chile Summary Some aspects of the reproductive biology of the meridional bands, during stage le, lead to accumu- glossiphoniid leech, Theromyzon rude, under labora- lation of ooplasm at both egg poles. In this manner, tory conditions, and the staging and structure of its the teloplasm or pole plasm forms. Completion of the uncleaved egg were studied. Sexually mature animals first cleavage furrow, by the end of stage If, is form breeding communities and fertilization occurs in preceded by dorsoventral flattening of the egg and the ovLsacs, presumably around the time of egg rearrangement of its teloplasm and perinuclear laying. Opposition may be postponed for hours or plasm. Structure of the early uncleaved egg has been days, but the eggs in the ovisacs remain blocked at studied with transmission and scanning electron mi- first meiotic metaphase. Development of the croscopy of intact or permeabilized preparations. The uncleaved egg, from the time of oviposit ion to com- plasmalemma forms numerous long and some short pletion of the first cleavage division, has been sub- microvilli evenly distributed across the egg surface. divided into six stages. At 20 °C, the six developmental The ectoplasm includes many vesicles, mitochondria, stages take 5-6 h. Characterization of' the stages is granules and an elaborate network of filament based on observations of both live and fixed/cleared bundles. -
Spinal Reflexes
Spinal Reflexes Lu Chen, Ph.D. MCB, UC Berkeley 1 Simple reflexes such as stretch reflex require coordinated contraction and relaxation of different muscle groups Categories of Muscle Based on Direction of Motion Flexors Æ reduce the angle of joints Extensors Æ increase the angle of joints Categories of Muscle Based on Movement Agonist Æmuscle that serves to move the joint in the same direction as the studied muscle Antagonist Æ muscle that moves the joint in the opposite direction 2 1 Muscle Spindles •Small encapsulated sensory receptors that have a Intrafusal muscle spindle-like shape and are located within the fibers fleshy part of the muscle •In parallel with the muscle fibers capsule •Does not contribute to the overall contractile Sensory force endings •Mechanoreceptors are activated by stretch of the central region Afferent axons •Due to stretch of the whole muscle Efferent axons (including intrafusal f.) •Due to contraction of the polar regions of Gamma motor the intrafusal fibers endings 3 Muscle Spindles Organization 2 kinds of intrafusal muscle fibers •Nuclear bag fibers (2-3) •Dynamic •Static •Nuclear chain fibers (~5) •Static 2 types of sensory fibers •Ia (primary) - central region of all intrafusal fibers •II (secondary) - adjacent to the central region of static nuclear bag fibers and nuclear chain fibers Intrafusal fibers stretched Sensory ending stretched, (loading the spindle) increase firing Muscle fibers lengthens Sensory ending stretched, (stretched) increase firing Spindle unloaded, Muscle fiber shortens decrease firing 4 2 Muscle Spindles Organization Gamma motor neurons innervate the intrafusal muscle fibers. Activation of Shortening of the polar regions gamma neurons of the intrafusal fibers Stretches the noncontractile Increase firing of the center regions sensory endings Therefore, the gamma motor neurons provide a mechanism for adjusting the sensitivity of the muscle spindles.