scholarly journals Thermal acclimation leads to variable muscle responses in two temperate labrid fishes

2020 ◽  
Vol 223 (24) ◽  
pp. jeb235226
Author(s):  
Clinton J. Moran ◽  
Kamryn E. Jebb ◽  
Leksi Travitz ◽  
David J. Coughlin ◽  
Shannon P. Gerry
Keyword(s):  
Muscle Power ◽  
Fiber Type ◽  
Poor Performance ◽  
Fish Distribution ◽  
Abiotic Factor ◽  
Cold Temperatures ◽  
Heavy Chains ◽  
Physiological Processes ◽  
As Species ◽  
Effects Of Temperature

ABSTRACTTemperature can be a key abiotic factor in fish distribution, as it affects most physiological processes. Specifically, temperature can affect locomotor capabilities, especially as species are exposed to temperatures nearing their thermal limits. In this study, we aimed to understand the effects of temperature on muscle in two labrids that occupy the Northwest Atlantic Ocean. When exposed to cold temperatures in autumn, cunner (Tautogolabrus adspersus) and tautog (Tautoga onitis) go into a state of winter dormancy. Transitions into dormancy vary slightly, where tautog will make short migrations to overwintering habitats while cunner overwinter in year-round habitats. To understand how muscle function changes with temperature, we held fish for 4 weeks at either 5 or 20°C and then ran muscle kinetic and workloop experiments at 5, 10 and 20°C. Following experiments, we used immunohistochemistry staining to identify acclimation effects on myosin isoform expression. Muscle taken from warm-acclimated cunner performed the best, whereas there were relatively few differences among the other three groups. Cunner acclimated at both temperatures downregulated the myosin heavy chain, suggesting a transition in fiber type from slow-oxidative to fast-glycolytic. This change did not amount to a detectable difference in muscle power production and kinetics. However, overall poor performance at cold temperatures could force these fishes into torpor to overwinter. Tautog, alternatively, retained myosin heavy chains, which likely increases locomotor capabilities when making short migrations to overwintering habitats.

scholarly journals Insects and low temperatures: from molecular biology to distributions and abundance

2002 ◽  
Vol 357 (1423) ◽  
pp. 849-862 ◽  
Author(s):  
J. S. Bale
Keyword(s):  
Cold Hardiness ◽  
Abiotic Factor ◽  
Thermal Thresholds ◽  
Physiological Processes ◽  
As Species ◽  
Pest Outbreaks ◽  
Rapid Cold Hardening ◽  
Establishment Potential ◽  
And Function ◽  
The Tropics

Insects are the most diverse fauna on earth, with different species occupying a range of terrestrial and aquatic habitats from the tropics to the poles. Species inhabiting extreme low–temperature environments must either tolerate or avoid freezing to survive. While much is now known about the synthesis, biochemistry and function of the main groups of cryoprotectants involved in the seasonal processes of acclimatization and winter cold hardiness (ice–nucleating agents, polyols and antifreeze proteins), studies on the structural biology of these compounds have been more limited. The recent discovery of rapid cold–hardening, ice–interface desiccation and the daily resetting of critical thermal thresholds affecting mortality and mobility have emphasized the role of temperature as the most important abiotic factor, acting through physiological processes to determine ecological outcomes. These relationships are seen in key areas such as species responses to climate warming, forecasting systems for pest outbreaks and the establishment potential of alien species in new environments.

Sexually dimorphic expression of myosin heavy chains in the adult mouse masseter

2000 ◽  
Vol 89 (1) ◽  
pp. 251-258 ◽  
Author(s):  
Jane M. Eason ◽  
Gail A. Schwartz ◽  
Grace K. Pavlath ◽  
Arthur W. English
Keyword(s):  
Adult Mouse ◽  
Fiber Type ◽  
Masticatory Muscles ◽  
Sexually Dimorphic ◽  
Heavy Chains ◽  
Tissue Sections ◽  
Type Composition ◽  
Sexually Dimorphic Expression ◽  
Dimorphic Expression

Little is known regarding the role of androgenic hormones in the maintenance of myosin heavy chain (MHC) composition of rodent masticatory muscles. Because the masseter is the principal jaw closer in rodents, we felt it was important to characterize the influence of androgenic hormones on the MHC composition of the masseter. To determine the extent of sexual dimorphism in the phenotype of masseter muscle fibers of adult (10-mo-old) C57 mice, we stained tissue sections with antibodies specific to type IIa and IIb MHC isoforms. Females contain twice as many fibers containing the IIa MHC as males, and males contain twice as many fibers containing the IIb MHC as females. There is a modest amount of regionalization of MHC phenotypes in the mouse masseter. The rostral portions of the masseter are composed mostly of type IIa fibers, whereas the midsuperficial and caudal regions contain mostly type IIb fibers. Using immunoblots, we showed that castration results in an increase in the expression of type IIa MHC fibers in males. Ovariectomy has no effect on the fiber type composition in females. We conclude that testosterone plays a role in the maintenance of MHC expression in the adult male mouse masseter.

scholarly journals The effect of temperature and thermal acclimation on the sustainable performance of swimming scup

2007 ◽  
Vol 362 (1487) ◽  
pp. 1995-2016 ◽  
Author(s):  
Lawrence C Rome
Keyword(s):  
Steady State ◽  
Relaxation Rate ◽  
Power Output ◽  
Muscle Power ◽  
Thermal Acclimation ◽  
The Body ◽  
Effect Of Temperature ◽  
Cold Temperatures ◽  
Duty Cycles ◽  
Red Muscle

There is a significant reduction in overall maximum power output of muscle at low temperatures due to reduced steady-state (i.e. maximum activation) power-generating capabilities of muscle. However, during cyclical locomotion, a further reduction in power is due to the interplay between non-steady-state contractile properties of muscle (i.e. rates of activation and relaxation) and the stimulation and the length-change pattern muscle undergoes in vivo . In particular, even though the relaxation rate of scup red muscle is slowed greatly at cold temperatures (10°C), warm-acclimated scup swim with the same stimulus duty cycles at cold as they do at warm temperature, not affording slow-relaxing muscle any additional time to relax. Hence, at 10°C, red muscle generates extremely low or negative work in most parts of the body, at all but the slowest swimming speeds. Do scup shorten their stimulation duration and increase muscle relaxation rate during cold acclimation? At 10°C, electromyography (EMG) duty cycles were 18% shorter in cold-acclimated scup than in warm-acclimated scup. But contrary to the expectations, the red muscle did not have a faster relaxation rate, rather, cold-acclimated muscle had an approximately 50% faster activation rate. By driving cold- and warm-acclimated muscle through cold- and warm-acclimated conditions, we found a very large increase in red muscle power during swimming at 10°C. As expected, reducing stimulation duration markedly increased power output. However, the increased rate of activation alone produced an even greater effect. Hence, to fully understand thermal acclimation, it is necessary to examine the whole system under realistic physiological conditions.

scholarly journals Changes in Muscle Power and Muscle Morphology with Different Volumes of Fast Eccentric Half-Squats

Sports ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 164 ◽  
Author(s):  
Evangelia Zacharia ◽  
Polyxeni Spiliopoulou ◽  
Spyridon Methenitis ◽  
Angeliki-Nikoletta Stasinaki ◽  
Nikolaos Zaras ◽  
...  
Keyword(s):  
Muscle Power ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Power Performance ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Muscle Morphology ◽  
Strength Performance ◽  
Type Composition ◽  
Before And After

The aim of the study was to evaluate power performance and muscle morphology adaptations in response to 5 weeks of fast-eccentric squat training (FEST) performed twice per week, with three different training volumes. Twenty-five moderately trained females were assigned into three groups performing eight repetitions of FEST of either four sets (4 × 8 group; N = 9), 6 sets (6 × 8 group; N = 8) or eight sets (8 × 8 group, N = 8). Before and after the intervention, countermovement jumping height (CMJh) and power (CMJp), half squat maximal strength (1-RM), quadriceps cross-sectional area (QCSA) and vastus lateralis (VL) architecture and fiber type composition were evaluated. Significant increases (p < 0.05) were found for all groups, with no differences among them in 1-RM (4 × 8: 14.8 ± 8.2%, 6 × 8: 13.1 ± 9.2% and 8 × 8: 21.6 ± 7.0%), CMJh (4 × 8: 12.5 ± 8.5%, 6 × 8: 11.3 ± 9.3% and 8 × 8: 7.0 ± 6.2%), CMJp (4 × 8: 9.1 ± 6.0%, 6 × 8: 7.1 ± 5.2% and 8 × 8: 5.0 ± 3.9%) and QCSA (4 × 8: 7.7 ± 4.7%, 6 × 8: 9.0 ± 6.8% and 8 × 8: 8.2 ± 6.5%). Muscle fiber type distribution remained unaltered after training in all groups. VL fascicle length increased and fascicle angle decreased only in 6 × 8 and 8 × 8 groups. In conclusion, four sets of eight fast-eccentric squats/week increase lower body power and strength performance and maintain type IIX muscle fibers after 5 weeks, at least in moderately trained females.

Morphology, Physiology, Behavior, and Ecology of Perca fluviatilis L. and P. flavescens Mitchill

1977 ◽  
Vol 34 (10) ◽  
pp. 1504-1514 ◽  
Author(s):  
J. E. Thorpe
Keyword(s):  
Yellow Perch ◽  
Perca Fluviatilis ◽  
Gonadal Development ◽  
Light Responses ◽  
Total Food ◽  
As Species ◽  
Fish Predators ◽  
Spawning Time ◽  
Effects Of Temperature ◽  
First Maturity

A review of literature on Perca fluviatilis and P. flavescens indicated one difference (in the position of the predorsal bone) sufficient to maintain their separateness as species. Otherwise they are overwhelmingly equivalent biologically. Their distributions are limited by the same effects of temperature, current speed, salinity, and dissolved oxygen. They are similar in gonadal development and age at first maturity; in the effects of water temperature and latitude on spawning time, and of environmental fertility on fecundity; in spawning behavior, fecundity, and the course of larval development. Growth capacities are similar and their expression subject to population density and temperature in the same way. Both species are adapted to a diet of small live animals, but will take whatever is available; cannibalism is characteristic, and may begin at the same early feeding stage. The two species show similarities in diurnal periodicity of feeding and in total food consumption. They also have the same pattern of development of light responses, of schooling, of activity and of daily and seasonal migrations. Within the fish community they fulfill the same role as converters of invertebrate foods into a form suitable for consumption by terminal fish predators, especially Stizostedion spp., influencing the population dynamics of their predators in similar ways. Key words: Percidae, morphology, physiology, ecology, Perca, life history, growth, reproduction, yellow perch, Eurasian perch

scholarly journals ACTN3 (R577X) genotype is associated with fiber type distribution

2007 ◽  
Vol 32 (1) ◽  
pp. 58-63 ◽  
Author(s):  
Barbara Vincent ◽  
Katrien De Bock ◽  
Monique Ramaekers ◽  
Els Van den Eede ◽  
Marc Van Leemputte ◽  
...  
Keyword(s):  
Muscle Fiber ◽  
Muscle Power ◽  
Control Function ◽  
Stop Codon ◽  
Fiber Type ◽  
Premature Stop Codon ◽  
Muscle Fiber Type ◽  
Vastus Lateralis Muscle ◽  
Type Distribution ◽  
Fiber Type Distribution

α-Actinin-3 is a Z-disc structural protein found only in type II muscle fibers. The X allele of the R577X polymorphism in the ACTN3 gene results in a premature stop codon and α-actinin-3 deficiency in XX homozygotes. Associations between the R577X polymorphism and the muscle-power performance of elite athletes have been described earlier. About 45% of the fiber type proportions are determined by genetic factors. The ACTN3 variant could be one of the contributing genes in the heritability of fiber type distribution through its interaction with calcineurin. The aim of this study was to quantify the association between the polymorphism and muscle fiber type distribution and fast-velocity knee extension strength. Ninety healthy young men (18–29 y) were genotyped for ACTN3 R577X. Knee extensor strength was measured isometrically (45°) and at different dynamic velocities (100–300°/s) on a programmable dynamometer. Twenty-two XX and twenty-two RR subjects underwent a biopsy of the right vastus lateralis muscle. Fiber type composition was determined by immunohistochemistry. Homozygotes for the R allele show significantly higher relative dynamic quadriceps torques at 300°/s, compared with XX carriers ( P < 0.05). Fiber type characteristics differed significantly between the two genotype groups. The percentage surface and number of type IIx fibers were greater in the RR than the XX genotype group ( P < 0.05), and α-actinin-3 protein content is systematically higher in type IIx compared with type IIa fibers (staining intensity ratio IIx to IIa = 1.17). This study shows that the mechanism, by which the ACTN3 polymorphism has its effect on muscle power, might rely on a control function of fiber type proportions.

scholarly journals Histochemical, biochemical, and ultrastructural analyses of single human muscle fibers, with special reference to the C-fiber population.

1992 ◽  
Vol 40 (4) ◽  
pp. 563-568 ◽  
Author(s):  
R S Staron ◽  
R S Hikida
Keyword(s):  
Fiber Type ◽  
Vastus Lateralis ◽  
Oxidative Capacity ◽  
Vastus Lateralis Muscle ◽  
Type I ◽  
Fiber Types ◽  
Heavy Chains ◽  
C Fibers ◽  
C Fiber ◽  
Ph Range

A muscle biopsy from the vastus lateralis muscle of a strength-trained woman was found to contain an unusual fiber type composition and was analyzed by histochemical, biochemical, and ultrastructural techniques. Special attention was given to the C-fibers, which comprised over 15% of the total fiber number in the biopsy. The mATPase activity of the C-fibers remained stable to varying degrees over the pH range normally used for routine mATPase histochemistry. Although a continuum existed, the C-fibers were histochemically subdivided into three main fiber types: IC, IIC, and IIAC. The IC fibers were histochemically more similar to the Type I, the IIAC were more similar to the Type IIA, and the IIC were darkly stained throughout the pH range. Biochemical analysis revealed that all C-fibers coexpressed myosin heavy chains (MHC) I and IIa in variable ratios. The histochemical staining intensity correlated with the myosin heavy chain composition such that the Type IC fibers contained a greater ratio of MHCI/MHCIIa, the IIAC contained a greater ratio of MHCIIa/MHCI, and the Type IIC contained equal amounts of these two heavy chains. Ultrastructural data of the C-fiber population revealed an oxidative capacity between fiber Types I and IIA and suggested a range of mitochondrial volume percent from highest to lowest such that I greater than IC greater than IIC greater than IIA-C greater than IIA. Under physiological conditions, it appears that the IC fibers represent Type I fibers that additionally express some fast characteristics, whereas the Type IIAC are Type IIA fibers that additionally express some slow characteristics. Fibers expressing a 50:50 mixture of MHCI and MHCIIa (IIC fibers) were rarely found. It is not known whether C-fibers represent a distinct population between the fast- and slow-twitch fibers that is specifically adapted to a particular usage or whether they are transforming fibers in the process of going from fast to slow or slow to fast.

scholarly journals Testing the reliability of standard and complementary DNA barcodes for the monocot subfamily Alooideae from South Africa

Genome ◽  
2017 ◽  
Vol 60 (4) ◽  
pp. 337-347 ◽  
Author(s):  
Barnabas H. Daru ◽  
Michelle van der Bank ◽  
Abubakar Bello ◽  
Kowiyou Yessoufou
Keyword(s):  
Dna Barcode ◽  
Poor Performance ◽  
Species Level ◽  
Discriminatory Power ◽  
Species Boundaries ◽  
Species Discrimination ◽  
Data Set ◽  
As Species ◽  
History Of ◽  
Combined Data

Although a standard DNA barcode has been identified for plants, it does not always provide species-level specimen identifications for investigating important ecological questions. In this study, we assessed the species-level discriminatory power of standard (rbcLa + matK) and complementary barcodes (ITS1 and trnH-psbA) within the subfamily Alooideae (Asphodelaceae), a large and recent plant radiation, whose species are important in horticulture yet are threatened. Alooideae has its centre of endemism in southern Africa, with some outlier species occurring elsewhere in Africa and Madagascar. We sampled 360 specimens representing 235 species within all 11 genera of the subfamily. With three distance-based methods, all markers performed poorly for our combined data set, with the highest proportion of correct species-level specimen identifications (30%) found for ITS1. However, when performance was assessed across genera, the discriminatory power varied from 0% for all single markers and combinations in Gasteria to 63% in Haworthiopsis, again for ITS1, suggesting that DNA barcoding success may be related to the evolutionary history of the lineage considered. Although ITS1 could be a good barcode for Haworthiopsis, the generally poor performance of all markers suggests that Alooideae remains a challenge. As species boundaries within Alooideae remain controversial, we call for continued search for suitable markers or the use of genomics approaches to further explore species discrimination in the group.

Relief Tanks: Parameters to Consider When Designing Relief Systems and Connections to Tanks

2020 ◽  
Author(s):  
Emma Perez
Keyword(s):  
Cold Weather ◽  
Transient Pressure ◽  
Relief Valve ◽  
Cold Temperatures ◽  
Oil Storage ◽  
Effects Of Temperature ◽  
Relief System ◽  
And Storage ◽  
Proper Operation ◽  
Stagnant Fluid

Abstract Oil Storage facilities (terminals) are usually designed with a pressure rating lower than the rating of the pipeline transporting the fluids. During abnormal operations, terminal piping can be subject to unexpected transient pressure surges that can exceed the allowed values. Mitigations are required a common one is installing a relief system. When a relief valve is installed, it is connected to a tank and the location of this relief tank is critical for the proper operation of the relief system and the overall mitigation of pressure surges. Relief design needs to take into account the length and layout of the piping. Facilities in the northern hemisphere contain pipes installed above ground and prone to experiencing cold temperatures during winter months. If the fluid is stagnant in these pipes, the cold weather increases the viscosity of the fluid. If the relief valve activates, the fluid that has been stagnant in the pipe needs to be pushed out of the pipe and into the tank. This requires a high pressure from the system and is directly affected by the distance of the pipe and the properties of the stagnant fluid. This paper will show how transient pressures change for length of pipe and for varied viscosities of the stagnant fluid. With these findings, engineers can improve their understanding of the effects of temperature and length on surge pressures and they can design safer systems for liquid transportation and storage.

Sign in / Sign up

Export Citation Format

Share Document