Biomaterial Database

The relationship of adenosine triphosphatase activity to tension and power output of insect flight muscle. 1975

J Pybus, and R T Tregear

1. On a simple model of actomyosin interaction, the tension cost (ATP hydrolysed/unit tension) and the frequency of low amplitude oscillation optimum for work production are both determined by the rate of detachment from the actin filament of the myosin crossbridge. To test this model, the two parameters were measured under different conditions using glycerol-extracted Lethocerus cordofanus dorsal longitudinal flight muscle fibres. 2. The ATPase activity of the static muscle rose by an amount approximately proportional to the rise in tension as the muscle was stretched. 3. When the muscle fibres were sinusoidally oscillated at 5-10 Hz by 2% of their resting length they produced a large amount of mechanical power and hydrolysed approximately twice as much ATP per unit mean tension as they did when static. The ATPase activity was linearly related to the mean tension during oscillation. 4. The experiments were repeated at temperatures between 12 and 30 degrees C and the tension cost and the optimal frequency of oscillation of the fibres were found to rise with temperature. 5. Removal of phosphate from the incubating medium reduced both the tension cost and the optimal working frequency. Addition of pyrophosphate or sulphate reduced both parameters still further. 6. From these results the tension cost of static muscle was shown to be proportional to its optimal working frequency. 7. ATPase activity rose monotonically with power production at work-producing frequencies and at moderate degrees of stretch. A high absolute efficiency was found under a wide range of conditions. 8. The proportionality between tension cost and optimal frequency is evidence for the proposed model of actomyosin interaction.

UI	MeSH Term	Description	Entries
D007313	Insecta	Members of the phylum ARTHROPODA composed or organisms characterized by division into three parts: head, thorax, and abdomen. They are the dominant group of animals on earth with several hundred thousand different kinds. Three orders, HEMIPTERA; DIPTERA; and SIPHONAPTERA; are of medical interest in that they cause disease in humans and animals. (From Borror et al., An Introduction to the Study of Insects, 4th ed, p1).	Insects,Insect
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D010710	Phosphates	Inorganic salts of phosphoric acid.	Inorganic Phosphate,Phosphates, Inorganic,Inorganic Phosphates,Orthophosphate,Phosphate,Phosphate, Inorganic
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011756	Diphosphates	Inorganic salts of phosphoric acid that contain two phosphate groups.	Diphosphate,Pyrophosphate Analog,Pyrophosphates,Pyrophosphate Analogs,Analog, Pyrophosphate
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D003470	Culture Media	Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.	Media, Culture
D004734	Energy Metabolism	The chemical reactions involved in the production and utilization of various forms of energy in cells.	Bioenergetics,Energy Expenditure,Bioenergetic,Energy Expenditures,Energy Metabolisms,Expenditure, Energy,Expenditures, Energy,Metabolism, Energy,Metabolisms, Energy