{"title":"Thermal Stability of Contractile Proteins in Bat Wing Muscles Explains Differences in Temperature Dependence of Whole-Muscle Shortening Velocity.","authors":"Andrea D Rummel, Sharon M Swartz, Richard L Marsh","doi":"10.1086/722449","DOIUrl":null,"url":null,"abstract":"<p><p>AbstractMuscle contractile properties are dependent on temperature: cooler temperatures generally slow contractile rates. Contraction and relaxation are driven by underlying biochemical systems, which are inherently sensitive to temperature. <i>Carollia perspicillata</i>, a small Neotropical bat, experiences large temperature differentials among body regions, resulting in a steep gradient in temperature along the wing. Although the bats maintain high core body temperatures during flight, the wing muscles may operate at more than 10°C below body temperature. Partially compensating for these colder operating temperatures, distal wing muscles have lower temperature sensitivities in their contractile properties, including shortening velocity, relative to the proximal pectoralis. Shortening velocity is correlated with the activity of myosin ATPase, an enzyme that drives the cross-bridge cycle. We hypothesized that the thermal properties of myofibrillar ATPase from the pectoralis and forearm muscles of the bat wing would correlate with the temperature sensitivity of those muscles. Using myofibrillar ATPases from the proximal and distal muscles, we measured enzyme activity across a range of temperatures and enzyme thermal stability after heat incubation across a range of time points. We found that forearm muscle myofibrillar ATPase was significantly less thermally stable than pectoralis myofibrillar ATPase but that there was no significant difference in the acute temperature dependence of enzyme activity between the two muscles.</p>","PeriodicalId":54609,"journal":{"name":"Physiological and Biochemical Zoology","volume":"96 2","pages":"100-105"},"PeriodicalIF":1.8000,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physiological and Biochemical Zoology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1086/722449","RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
AbstractMuscle contractile properties are dependent on temperature: cooler temperatures generally slow contractile rates. Contraction and relaxation are driven by underlying biochemical systems, which are inherently sensitive to temperature. Carollia perspicillata, a small Neotropical bat, experiences large temperature differentials among body regions, resulting in a steep gradient in temperature along the wing. Although the bats maintain high core body temperatures during flight, the wing muscles may operate at more than 10°C below body temperature. Partially compensating for these colder operating temperatures, distal wing muscles have lower temperature sensitivities in their contractile properties, including shortening velocity, relative to the proximal pectoralis. Shortening velocity is correlated with the activity of myosin ATPase, an enzyme that drives the cross-bridge cycle. We hypothesized that the thermal properties of myofibrillar ATPase from the pectoralis and forearm muscles of the bat wing would correlate with the temperature sensitivity of those muscles. Using myofibrillar ATPases from the proximal and distal muscles, we measured enzyme activity across a range of temperatures and enzyme thermal stability after heat incubation across a range of time points. We found that forearm muscle myofibrillar ATPase was significantly less thermally stable than pectoralis myofibrillar ATPase but that there was no significant difference in the acute temperature dependence of enzyme activity between the two muscles.
期刊介绍:
Physiological and Biochemical Zoology: Ecological and Evolutionary Approaches primarily publishes original research in animal physiology and biochemistry as considered from behavioral, ecological, and/or evolutionary perspectives. Studies at all levels of biological organization from the molecular to the whole organism are welcome, and work that integrates across levels of organization is particularly encouraged. Studies that focus on behavior or morphology are welcome, so long as they include ties to physiology or biochemistry, in addition to having an ecological or evolutionary context.
Subdisciplines of interest include nutrition and digestion, salt and water balance, epithelial and membrane transport, gas exchange and transport, acid-base balance, temperature adaptation, energetics, structure and function of macromolecules, chemical coordination and signal transduction, nitrogen metabolism and excretion, locomotion and muscle function, biomechanics, circulation, behavioral, comparative and mechanistic endocrinology, sensory physiology, neural coordination, and ecotoxicology ecoimmunology.