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William M Kier - One of the best experts on this subject based on the ideXlab platform.
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specialization for rapid excitation in Fast squid tentacle Muscle involves action potentials absent in slow arm Muscle
The Journal of Experimental Biology, 2020Co-Authors: William F Gilly, Corbin Renken, Joshua J C Rosenthal, William M KierAbstract:ABSTRACT An important aspect of the performance of many Fast Muscle Fiber types is rapid excitation. Previous research on the cross-striated Muscle Fibers responsible for the rapid tentacle strike in squid has revealed the specializations responsible for high shortening velocity, but little is known about excitation of these Fibers. Conventional whole-cell patch recordings were made from tentacle Fibers and the slower obliquely striated Muscle Fibers of the arms. The Fast-contracting tentacle Fibers show an approximately 10-fold greater sodium conductance than that of the arm Fibers and, unlike the arm Fibers, the tentacle Muscle Fibers produce action potentials. In situ hybridization using an antisense probe to the voltage-dependent sodium channel present in this squid genus shows prominent expression of sodium channel mRNA in tentacle Fibers but undetectable expression in arm Fibers. Production of action potentials by tentacle Muscle Fibers and their absence in arm Fibers is likely responsible for the previously reported greater twitch–tetanus ratio in the tentacle versus the arm Fibers. During the rapid tentacle strike, a few closely spaced action potentials would result in maximal activation of transverse tentacle Muscle. Activation of the slower transverse Muscle Fibers in the arms would require summation of excitatory postsynaptic potentials over a longer time, allowing the precise modulation of force required for supporting slower movements of the arms.
William F Gilly - One of the best experts on this subject based on the ideXlab platform.
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specialization for rapid excitation in Fast squid tentacle Muscle involves action potentials absent in slow arm Muscle
The Journal of Experimental Biology, 2020Co-Authors: William F Gilly, Corbin Renken, Joshua J C Rosenthal, William M KierAbstract:ABSTRACT An important aspect of the performance of many Fast Muscle Fiber types is rapid excitation. Previous research on the cross-striated Muscle Fibers responsible for the rapid tentacle strike in squid has revealed the specializations responsible for high shortening velocity, but little is known about excitation of these Fibers. Conventional whole-cell patch recordings were made from tentacle Fibers and the slower obliquely striated Muscle Fibers of the arms. The Fast-contracting tentacle Fibers show an approximately 10-fold greater sodium conductance than that of the arm Fibers and, unlike the arm Fibers, the tentacle Muscle Fibers produce action potentials. In situ hybridization using an antisense probe to the voltage-dependent sodium channel present in this squid genus shows prominent expression of sodium channel mRNA in tentacle Fibers but undetectable expression in arm Fibers. Production of action potentials by tentacle Muscle Fibers and their absence in arm Fibers is likely responsible for the previously reported greater twitch–tetanus ratio in the tentacle versus the arm Fibers. During the rapid tentacle strike, a few closely spaced action potentials would result in maximal activation of transverse tentacle Muscle. Activation of the slower transverse Muscle Fibers in the arms would require summation of excitatory postsynaptic potentials over a longer time, allowing the precise modulation of force required for supporting slower movements of the arms.
Joshua J C Rosenthal - One of the best experts on this subject based on the ideXlab platform.
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specialization for rapid excitation in Fast squid tentacle Muscle involves action potentials absent in slow arm Muscle
The Journal of Experimental Biology, 2020Co-Authors: William F Gilly, Corbin Renken, Joshua J C Rosenthal, William M KierAbstract:ABSTRACT An important aspect of the performance of many Fast Muscle Fiber types is rapid excitation. Previous research on the cross-striated Muscle Fibers responsible for the rapid tentacle strike in squid has revealed the specializations responsible for high shortening velocity, but little is known about excitation of these Fibers. Conventional whole-cell patch recordings were made from tentacle Fibers and the slower obliquely striated Muscle Fibers of the arms. The Fast-contracting tentacle Fibers show an approximately 10-fold greater sodium conductance than that of the arm Fibers and, unlike the arm Fibers, the tentacle Muscle Fibers produce action potentials. In situ hybridization using an antisense probe to the voltage-dependent sodium channel present in this squid genus shows prominent expression of sodium channel mRNA in tentacle Fibers but undetectable expression in arm Fibers. Production of action potentials by tentacle Muscle Fibers and their absence in arm Fibers is likely responsible for the previously reported greater twitch–tetanus ratio in the tentacle versus the arm Fibers. During the rapid tentacle strike, a few closely spaced action potentials would result in maximal activation of transverse tentacle Muscle. Activation of the slower transverse Muscle Fibers in the arms would require summation of excitatory postsynaptic potentials over a longer time, allowing the precise modulation of force required for supporting slower movements of the arms.
Corbin Renken - One of the best experts on this subject based on the ideXlab platform.
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specialization for rapid excitation in Fast squid tentacle Muscle involves action potentials absent in slow arm Muscle
The Journal of Experimental Biology, 2020Co-Authors: William F Gilly, Corbin Renken, Joshua J C Rosenthal, William M KierAbstract:ABSTRACT An important aspect of the performance of many Fast Muscle Fiber types is rapid excitation. Previous research on the cross-striated Muscle Fibers responsible for the rapid tentacle strike in squid has revealed the specializations responsible for high shortening velocity, but little is known about excitation of these Fibers. Conventional whole-cell patch recordings were made from tentacle Fibers and the slower obliquely striated Muscle Fibers of the arms. The Fast-contracting tentacle Fibers show an approximately 10-fold greater sodium conductance than that of the arm Fibers and, unlike the arm Fibers, the tentacle Muscle Fibers produce action potentials. In situ hybridization using an antisense probe to the voltage-dependent sodium channel present in this squid genus shows prominent expression of sodium channel mRNA in tentacle Fibers but undetectable expression in arm Fibers. Production of action potentials by tentacle Muscle Fibers and their absence in arm Fibers is likely responsible for the previously reported greater twitch–tetanus ratio in the tentacle versus the arm Fibers. During the rapid tentacle strike, a few closely spaced action potentials would result in maximal activation of transverse tentacle Muscle. Activation of the slower transverse Muscle Fibers in the arms would require summation of excitatory postsynaptic potentials over a longer time, allowing the precise modulation of force required for supporting slower movements of the arms.
Orjan Hagen - One of the best experts on this subject based on the ideXlab platform.
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growth performance Fast Muscle development and chemical composition of juvenile lumpfish cyclopterus lumpus fed diets incorporating soy and pea protein concentrates
Aquaculture Reports, 2020Co-Authors: Florence Perera Willora, Nimalan Nadanasabesan, Helene Ronquist Knutsen, Cui Liu, Mette Sorensen, Orjan HagenAbstract:Abstract Lumpfish (Cyclopterus lumpus) are widely applied as biological delousers in open net-pen farming of Atlantic salmon. As a species new to farming it is necessary to obtain a comprehensive understanding of the capacity of lumpfish to utilize plant derived feed ingredients. A feeding trial lasting for 54 days was conducted to investigate the effects of replacing fishmeal (FM) with a mix of soy protein concentrate (SPC) and pea protein concentrate (PPC) on growth, body chemical composition, and Fast Muscle Fiber cellularity in juvenile lumpfish. Four isonitrogenous and isoenergetic diets (52 % crude protein and 14 % crude lipid) were formulated; a FM based diet was used as control (CTRL), and three experimental diets containing SPC and PPC (equal proportions of 1:1), replacing FM on weight basis at 25 % (PP25) 50 % (PP50) and 75 % (PP75). The fish grew from approximately 6.9 g to an average weight of 40.2 g in 54 days. Fish fed PP50 had significantly higher body weight, length and height compared to the other dietary groups. The whole body crude protein content of fish fed PP50 was significantly higher compared to the CTRL diet, while crude lipids were lower than those on CTRL and PP25 diets. Ash and dry matter did not differ among groups. Probability density functions showed no differences in Fast Muscle Fiber size distributions amongst feeding groups. A higher percentage of smaller Fibers in all feeding groups indicated hyperplasia was the dominant mechanism of Muscle growth during the experimental period. These results suggest that a mixture of SPC and PPC can replace up to 50 % of FM in diets for juvenile lumpfish without any adverse effects on growth, chemical composition and Fast Muscle Fiber cellularity.
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Muscle growth and changes in chemical composition of spotted wolffish juveniles (Anarhichas minor) fed diets with and without microalgae (Scenedesmus obliquus)
Elsevier, 2019Co-Authors: Helene Ronquist Knutsen, Mette Sorensen, O.h. Ottesen, A.m. Palihawadana, W. Sandaa, Orjan HagenAbstract:Spotted wolffish (Anarhichas minor) is a promising new candidate for cold-water fish farming, but knowledge is needed about its physiology and its capacity to utilize alternative feed ingredients. The aim of the study was to investigate Fast Muscle growth dynamics, changes in chemical composition as well as growth performance of spotted wolffish when fed diets with or without the microalgae Scenedesmus obliquus incorporated. Juvenile spotted wolffish were fed four diets containing fishmeal as the primary source of protein (CTR diet) or microalgae (Scenedesmus obliquus) replacing 4% (AL4 diet), 8% (AL8 diet) or 12% (AL12 diet) of the fishmeal. During the 12 week experiment, fish grew from an average weight of 140 g to 250 g. The results showed indications of Fast Muscle cellularity of spotted wolffish being affected by dietary algae inclusion as the control and AL4 groups appeared to be more strongly favored by hypertrophic growth compared to the AL8 and AL12 groups. The CTR and AL4 groups tended towards increased Muscle Fiber diameters and higher proportions of larger Muscle Fibers, while the AL8 and AL12 group tended towards similar or increased proportions of smaller Muscle Fibers at the end of the trial. Probability density functions showed no difference in Fast Muscle Fiber size distributions between dietary groups. Muscle crude protein and fat content tended to increase with growth in all treatment groups and Muscle mineral content was reduced in all groups fed diets containing Scenedesmus. At the end of the trial, hepatosomatic index was reduced in all treatment groups. Dietary replacement of fishmeal with Scenedesmus also affected skin coloration, with increasing yellowness observed with increasing microalgae replacement. This study indicates that spotted wolffish has the potential to use microalgae as an alternative to fishmeal in the diet. Keywords: nutrition, sustainable aquafeed, Muscle Fiber cellularity, Muscle growth, proximate composition, histology, alternative feed ingredient
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biochemical and structural factors contributing to seasonal variation in the texture of farmed atlantic halibut hippoglossus hippoglossus l flesh
Journal of Agricultural and Food Chemistry, 2007Co-Authors: Orjan Hagen, Christel Solberg, Ellen Sirnes, Ian A. JohnstonAbstract:Factors contributing to the texture of fish flesh, including pH, water content, density of Fast Muscle Fibers, and the concentration of collagen and hydroxylysyl pyridinoline (PYD) cross-links, were investigated post-rigor in commercially farmed Atlantic halibut (Hippoglossus hippoglossus L.). The fish was sampled every quarter for a 12 month period from May 2004 to May 2005. Hydroxyproline (HYP) as a measure of collagen and PYD were determined using a high-performance liquid chromatography (HPLC) method. An ANCOVA model with fork length and season as covariates were used to explore the seasonal effects on texture, pH, Muscle Fiber density, alkaline-insoluble collagen (a-i HYP), alkaline-soluble collagen (a-s HYP), and PYD cross-links. A multiple linear regression (MLR) showed that the most important factors contributing to texture were PYD > water (%) > a-i HYP > Fiber density, while pH and a-s HYP did not show any correlation to texture. The contribution of Fast Muscle Fiber density to texture was found to vary between sexes and with the season, contributing more in males and in the spring. The most important parameter affecting texture was PYD, explaining 64% (p < 0.001) of the total variation in a linear regression analysis. It is concluded that cross-linking processes are of great importance for the rigidity and strength of the collagen in Atlantic halibut flesh. Farmed halibut should be harvested in the fall or early winter when texture and nutrition are good to obtain optimal quality.