Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.4.1 (myosin ATPase)
 1,140 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Post-hatching growth of lateral muscle in a teleost fish, Sparus aurata (L) was studied morphometrically to identify and quantify muscle fibre hyperplasia and hypertrophy, and by in vivo nuclear labelling with 5-bromo-deoxyuridine to identify areas of myoblast proliferation. Muscle fibre types were identified principally by myosin ATPase histochemistry and immunostaining, and labelled nuclei were identified at light and electronmicroscope level by immunostaining with a specific monoclonal antibody. Hyperplastic growth was slow at hatching, but then increased to a maximum at the mid-point of larval life. Larval hyperplastic growth occurred by apposition of new fibres along proliferation zones, principally just under the lateral line and in the apical regions of the myotome, but also just under the superficial monolayer at intermediate positions. The first of these zones gave rise to slow and pink muscle fibres, in a process which continued through into postlarval life. The other zones added new fibres to the fast-white muscle layer in a process which was exhausted by the end of larval life. Post-larvally, between 60 and 90 days posthatching, a new hyperplastic process started in the fast-white muscle as nuclei proliferated and new muscle fibres were formed throughout the whole layer. This process resulted in a several-fold increase in the number of fast-white fibres over a few weeks, and then waned to very low levels in juveniles. Hyperplasia by apposition continued for some time postlarvally on the deep surface of the superficial monolayer, but at this stage gave rise to slow fibres only. Hypertrophic growth occurred at all ages, but was the dominant mechanism of muscle growth only in the juvenile and adult stages. Mechanisms giving rise to these different growth processes in fish muscle are discussed, and compared with muscle development in higher vertebrates.
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PMID:Differentiation and growth of muscle in the fish Sparus aurata (L): II. Hyperplastic and hypertrophic growth of lateral muscle from hatching to adult. 755 95

Hypertrophic responses to stretch are attenuated in slow-tonic muscles from old quail, relative to young birds. It is not known if the age-associated differences would be similar in fast-twitch muscles after stretch. This study compared the effect of 30 days of stretch overload on slow beta fibers and fast-alpha fibers in patagialis (PAT) muscles from young adult (YA) quail aged 12 weeks, old adult (OA) quail aged 52 weeks and the oldest (OO) quail, aged 90 weeks. The PAT muscle was stretched for 7, 14, 21, or 30 days by a sleeve that was attached to one wing. Birds received a subcutaneously implanted 5'-bromo-2'-deoxyuridine (BrdU) pellet that provided a constant release of 0.22mg BrdU/g body wt/day to label nuclei that had undergone DNA synthesis during stretch. Fiber cross-sectional area (CSA) was determined by planimetry from slow beta and fast-alpha fibers after identification by myosin ATPase. Harris hematoxylin was used to identify muscle nuclei. Muscle mass increased by 44.1 +/- 3.1, 32.6 +/- 3.9 and 25.7 +/- 4.3% in YA, OA and OO birds, respectively. Slow-beta fiber hypertrophy was observed at day 7 of stretch in all birds; however, YA birds had greater hypertrophy than the older birds. Fast-alpha fibers were unaffected by stretch. No significant difference was observed between PAT muscles from OA and OO birds. Total fiber number was not significantly elevated in the PAT muscle from any age group after 30 days of stretch. Activated satellite cells were not detected in stretched muscles of either young or old birds. This suggests that the increase in mean slow-beta fiber CSA was potentiated by existing myonuclei rather than by recruiting additional nuclei.
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PMID:Adaptations of myonuclei to hypertrophy in patagialis muscle fibers from aged quail. 881 1