Contraction dynamics and power production of pink muscle of the scup (Stenotomus chrysops).

1996 ◽  
Vol 199 (12) ◽  
pp. 2703-2712 ◽  
Author(s):  
D J Coughlin ◽  
G Zhang ◽  
L C Rome
Keyword(s):  
Fibre Orientation ◽  
Maximum Velocity ◽  
Power Production ◽  
Velocity Of Shortening ◽  
Red Muscle ◽  
Oscillatory Power ◽  
Myotomal Muscle ◽  
Longitudinal Fibre ◽  
Stenotomus Chrysops

Although the contribution of red muscle to sustained swimming in fish has been studied in detail in recent years, the role of pink myotomal muscle has not received attention. Pink myotomal muscle in the scup (Stenotomus chrysops) lies just medial to red muscle, has the same longitudinal fibre orientation and is recruited along with the red muscle during steady sustainable swimming. However, pink muscle has significantly faster rates of relaxation, and the maximum velocity of shortening of pink muscle (7.26 +/- 0.18 muscle lengths s-1, N = 9, at 20 degrees C, and 4.46 +/- 0.15 muscle lengths s-1, N = 6, at 10 degrees C; mean +/- S.E.M.) is significantly faster than that of red muscle. These properties facilitate higher mass-specific maximum oscillatory power production relative to that of red muscle at frequencies similar to the tailbeat frequency at maximum sustained swimming speeds in scup. Additionally, pink muscle is found in anatomical positions in which red muscle is produces very little power during swimming: the anterior region of the fish, which undergoes the lowest strain during swimming. Pink muscle produces more oscillatory power than red muscle under low-strain conditions (+/- 2-3%) and this may allow pink muscle to supplement the relatively low power generated by red muscle in the anterior regions of swimming scup.

scholarly journals The influence of temperature on muscle function in the fast swimming scup. II. The mechanics of red muscle

1992 ◽  
Vol 163 (1) ◽  
pp. 281-295 ◽  
Author(s):  
L. C. Rome ◽  
A. Sosnicki ◽  
I. H. Choi
Keyword(s):  
Isometric Force ◽  
Maximum Velocity ◽  
Design Constraint ◽  
Velocity Of Shortening ◽  
Red Muscle ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
The Mean ◽  
Important Design

To understand better how scup can swim twice as fast as carp with its red muscle, we measured the mechanical properties of red muscle bundles in scup. The values of the mean maximum velocity of shortening (Vmax) at 10 degrees C (3.32 muscle lengths s-1) and at 20 degrees C (5.55 muscle lengths s-1; Q10 = 1.69) were nearly the same as those in carp. Isometric force, however, was approximately 50% greater (183 kN m-2; Q10 = 1.08). The maximal power generation was correspondingly about 50% greater in scup than in carp (71 W kg-1 at 10 degrees C and 134 W kg-1 at 20 degrees C; Q10 = 1.88). The larger power output of its muscle may be important in the faster swimming of the scup. In addition, the fact that scup use a less undulatory style of swimming means that, when they are swimming twice as fast, their red muscle shortens at the same velocity (V) and with the same V/Vmax (0.37, i.e. where maximum power is generated) as that of carp. The importance of V/Vmax is further shown by the comparison of scup swimming at different temperatures. The 1.69-fold higher Vmax at 20 degrees C than at 10 degrees C enables scup to swim with a 1.67-fold faster V at 20 degrees C. Thus, at both 10 degrees C and 20 degrees C, red muscle is used only over the same narrow range of V/Vmax (0.17-0.37), where experiments on isolated muscle suggest that power and efficiency are maximal. Therefore, V/Vmax appears to be an important design constraint that limits the range of velocities over which muscle is used in vivo, both at different temperatures and in fast- and slow-locomoting species.

scholarly journals Power Output and Force-Velocity Relationship of Live Fibres from White Myotomal Muscle of the Dogfish, Scyliorhinus Canicula

1988 ◽  
Vol 140 (1) ◽  
pp. 187-197 ◽  
Author(s):  
N. A. CURTIN ◽  
R. C. WOLEDGE
Keyword(s):  
Power Output ◽  
Maximum Velocity ◽  
Muscle Fibres ◽  
Fish Length ◽  
Skinned Fibres ◽  
Step Method ◽  
Velocity Relationship ◽  
Velocity Of Shortening ◽  
Force Velocity ◽  
Myotomal Muscle

The relationship between force and velocity of shortening and between power and velocity were examined for myotomal muscle fibre bundles from the dogfish. The maximum velocity of shortening, mean value 4.8 ± 0.2 μms−1 half sarcomere−1 (±S.E.M., N = 13), was determined by the ‘slack step’ method (Edman, 1979) and was found to be independent of fish length. The force-velocity relationship was hyperbolic, except at the high-force end where the observations were below the hyperbola fitted to the rest of the data. The maximum power output was 91 ± 14 W kg−1 wet mass (±S.E.M., N = 7) at a velocity of shortening of 1.3 ± 0.13μms−1 halfsarcomere−1 (±S.E.M., N = 7). This power output is considerably higher than that previously reported for skinned fibres (Bone et al. 1986). Correspondingly the force-velocity relationship is less curved for intact fibres than for skinned fibres. The maximum swimming speed (normalized for fish length) predicted from the observed power output of the muscle fibres decreased with increasing fish size; it ranged from 12.9 to 7.8 fish lengths s−1 for fish 0155–0.645m in length.

Nitric oxide effects on shortening velocity and power production in the rat diaphragm

1996 ◽  
Vol 80 (3) ◽  
pp. 1065-1069 ◽  
Author(s):  
R. J. Morrison ◽  
C. C. Miller ◽  
M. B. Reid
Keyword(s):  
Nitric Oxide ◽  
Isometric Force ◽  
Maximum Velocity ◽  
Power Production ◽  
Ringer Solution ◽  
Fiber Bundles ◽  
Rat Diaphragm ◽  
Shortening Velocity ◽  
No Donor ◽  
Velocity Of Shortening

The present experiments tested nitric oxide (NO) effects on shortening velocity and power production in maximally activated rat diaphragm. Diaphragm fiber bundles (n = 10/group) were incubated at 37 degrees C in Krebs-Ringer solution containing no added drug (control), the NO synthase inhibitor N omega-nitro-L-arginine (L-NNA; 10 mM), the NO donor sodium nitroprusside (SNP; 1 mM), or a combination (L-NNA + SNP) Loaded shortening velocity was measured via the load-clamp technique over a range of afterloads. Force-velocity data were fitted to the Hill equation to determine maximum velocity of shortening (Vmax). Unloaded shortening velocity was measured in control and L-NNA-treated bundles (n = 12/group) by using the slack test. Maximal isometric force and unloaded shortening velocity were not altered by L-NNA. In contrast, L-NNA decreased maximum velocity of shortening (P < 0.05), loaded shortening velocity (P < 0.0001), and power production (P < 0.0001). All L-NNA effects were prevented by coincubating fiber bundles with L-NNA + SNP. SNP alone had no effect on any variable. These data indicate that endogenous NO is essential for optimal myofilament function during active shortening.

Metabolic biochemistry of water- vs. air-breathing fishes: muscle enzymes and ultrastructure

1978 ◽  
Vol 56 (4) ◽  
pp. 736-750 ◽  
Author(s):  
P. W. Hochachka ◽  
M. Guppy ◽  
H. E. Guderley ◽  
K. B. Storey ◽  
W. C. Hulbert
Keyword(s):  
White Muscle ◽  
Large Diameter ◽  
Oxidative Capacity ◽  
The Body ◽  
Muscle Enzymes ◽  
Air Breathing ◽  
Red Muscle ◽  
Phosphofructokinase Activity ◽  
Metabolic Biochemistry ◽  
Myotomal Muscle

To delineate what modifications in muscle metabolic biochemistry correlate with transition to air breathing in fishes, the myotomal muscles of aruana, an obligate water breather, and Arapaima, a related obligate air breather, were compared using electron microscopy and enzyme methods. White muscle in both species maintained a rather similar ultrastructure, characterized by large-diameter fibers, very few mitochondria, and few capillaries. However, aruana white muscle displayed nearly fivefold higher levels of pyruvate kinase, threefold higher levels of muscle-type lactate dehydrogenase, and a fourfold higher ratio of fructose diphosphatase –phosphofructokinase activity; at the same time, enzymes in aerobic metabolism occurred at about one-half the levels in Arapaima. Red muscle was never found in the myotomal mass of aruana, but in Arapaima, red muscle was present and seemed fueled by glycogen, lipid droplets never being observed. From these and other data, it was concluded that in myotomal muscle two processes correlate with the transition to air breathing in Amazon osteoglossids: firstly, an emphasis in oxidative metabolism, and secondly, a retention of red muscle. However, compared with more active water-breathing species, Arapaima sustains an overall dampening of enzyme activities in its myotomal muscle, which because of the large myotome mass explains why its overall metabolic rate is relatively low. By keeping the oxidative capacity of its myotomal muscle low, Arapaima automatically conserves O2 either for a longer time or for other more O2-requiring organs in the body, a perfectly understandable strategy for an air-breathing, diving fish, comparable with that observed in other diving vertebrates. A similar comparison was also made of two erythrinid fishes, one that skimmed the O2-rich surface layers of water and one that obtained three quarters of its O2 from water, one quarter from air. Ultrastructural and enzyme data led to the unexpected conclusion that the surface skimmer sustained a higher oxidative capacity in its myotomal muscles than did the facultative air breather.

Comparative force-velocity relation and analyses of myosin of dog atria and ventricles

1982 ◽  
Vol 243 (3) ◽  
pp. H391-H397 ◽  
Author(s):  
J. Wikman-Coffelt ◽  
H. Refsum ◽  
G. Hollosi ◽  
L. Rouleau ◽  
L. Chuck ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Calcium Concentration ◽  
Maximum Velocity ◽  
Calcium Sensitivity ◽  
Myofibrillar Proteins ◽  
Maximal Velocity ◽  
Velocity Of Shortening ◽  
Force Velocity ◽  
Normal Calcium ◽  
Actin Concentration

The isolated muscle and purified myofibrillar proteins of canine atria and ventricles were compared relative to force-velocity relations and rate of adenosine 5'-triphosphatase (ATPase) activity as a function of calcium concentrations. The maximal stress development of isolated trabeculae of canine atria was similar to that of canine right ventricular papillary muscles when analyzed at saturating calcium concentrations (7.5 mM); however, stress was less in the atria when studied at normal calcium concentrations (2.5 mM). The maximal velocity of shortening of atrial trabeculae was about 2.3 times higher than that of ventricular muscle. Regulated actomyosin characterized from the myofibrillar proteins of the two tissues gave directionally similar calcium sensitivity. The maximum velocity of shortening for actin-activated atrial myosin of the dog was approximately 1.8 times higher when the latter was analyzed as a function of actin concentration. Both maximal tension of isolated muscle and regulated actomyosin ATPase activity were dependent on calcium concentration.

scholarly journals Switching on an Environmentally Friendly and Affordable Light in Africa: Evaluation of the Role of Natural Gas

2019 ◽  
Vol 11 (1) ◽  
pp. 60-77
Author(s):  
Ishmael Ackah ◽  
Freda Opoku ◽  
Sarah Anang
Keyword(s):  
Natural Gas ◽  
Value Chain ◽  
Descriptive Analysis ◽  
Environmentally Friendly ◽  
Power Production ◽  
Energy Sources ◽  
Minimal Impact ◽  
Gas Potential ◽  
Desk Review

The purpose of this article is to review the dynamics of natural gas resources in Africa and evaluate how it can help solve the power challenges of the continent. This article develops from a descriptive analysis and desk review on natural gas and power. The key finding is that despite the increased discovery of natural gas in Africa, it has had minimal impact on power production. This study provides a descriptive overview and is limited to only natural gas. It does not consider how other energy sources can contribute to solving Africa’s power challenges. This article draws the attention of both policymakers and the investment community to the opportunities in the ‘natural gas-power’ value chain and the need to invest in gas infrastructure. An overview of the power challenges and natural gas potential of Africa is provided.

Optimal shortening velocities for in situ power production of rat soleus and plantaris muscles

1997 ◽  
Vol 273 (3) ◽  
pp. C1057-C1063 ◽  
Author(s):  
S. J. Swoap ◽  
V. J. Caiozzo ◽  
K. M. Baldwin
Keyword(s):  
Power Production ◽  
Sprague Dawley ◽  
Maximal Power ◽  
Cycle Frequency ◽  
Optimal Velocity ◽  
Velocity Of Shortening ◽  
Loop Technique ◽  
Length Changes ◽  
Work Loop

Force-velocity (FV) relationships have been used previously to calculate maximal power production and to identify an optimal velocity of shortening (V(opt)-fv) to produce such power in skeletal muscle. The cyclical nature of muscle position during locomotion for muscles such as the soleus and plantaris is such that either constant force or velocity is rarely attained. In the present study, the work loop technique, a technique developed to measure maximal attainable power output from muscles undergoing cyclic length changes, was undertaken to determine whether simulating in vivo function alters the power-velocity relationship of the soleus and plantaris and, in particular, the velocity of shortening that produces maximal power (V(opt)-wl). FV relationships were determined for both soleus (n = 4) and plantaris (n = 4) muscles in situ from adult female Sprague-Dawley rats by measuring shortening velocities during afterloaded isotonic contractions. The velocity that produced maximal power using FV relationships, V(opt)-fv, was 54.6 +/- 0.7 mm/s for the plantaris vs. 20.2 +/- 1.2 mm/s for the soleus. Then, the work loop technique was employed to measure net power from these same muscles at multiple cycling frequencies (1.5 to 4.0 Hz for the soleus; 4.0 to 8.0 Hz for the plantaris). Multiple power-velocity curves were generated (one at each cycle frequency) by varying the strain (1-8 mm). Thus, at each cycle frequency, V(opt)-wl could be identified. For both the plantaris and soleus, V(opt)-wl at each cycle frequency was not different from their respective V(opt)-fv value. Thus both fast and slow skeletal muscles have inherent optimal shortening velocities, identifiable with FV relationships, that dictate their respective maximal attainable mechanical power production using the work loop technique.

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