Energy metabolism and the fate of lactate during recovery from exercise in the Australian freshwater crayfish Cherax destructor

1986 ◽  
Vol 37 (5) ◽  
pp. 641 ◽  
Author(s):  
G Head ◽  
J Baldwin
Keyword(s):  
Oxygen Consumption ◽  
Recovery Period ◽  
High Energy ◽  
Freshwater Crayfish ◽  
Muscle Lactate ◽  
Cherax Destructor ◽  
Time Required ◽  
Australian Freshwater ◽  
Tail Muscle ◽  
Subsequent Disappearance

Recovery following tail flipping by C. destructor involves regeneration of arginine phosphate and ATP in the tail muscle and the removal of lactate. High-energy phosphate reserves return to pre-exercise levels after 60 min, which corresponds with the time required for behavioural recovery. During recovery, the oxygen consumption rate increases and lactate accumulates in the tail muscle. The subsequent disappearance of lactate from this muscle and appearance of elevated levels of lactate in the external medium indicate that tail muscle lactate is excreted rather than metabolized. It is estimated that 40% of the 22.5 �mol ATP per gram of tail muscle required for regenerating arginine phosphate and ATP is obtained from anaerobic glycolysis. The remainder is provided by oxidative phosphorylation associated with elevated oxygen consumption during the initial 35 min of the recovery period.

Phylogeny of the Australian freshwater crayfish Cherax destructor-complex (Decapoda : Parastacidae) inferred from four mitochondrial gene regions

2005 ◽  
Vol 19 (3) ◽  
pp. 209 ◽  
Author(s):  
Thuy T. T. Nguyen ◽  
Christopher M. Austin
Keyword(s):  
16S Rrna ◽  
Cytochrome Oxidase ◽  
Mitochondrial Gene ◽  
Large Subunit ◽  
Strong Support ◽  
Interspecific Variation ◽  
Rrna Gene ◽  
Freshwater Crayfish ◽  
Cherax Destructor ◽  
Australian Freshwater

The phylogenetic relationships among 32 individuals of Australian freshwater crayfish belonging to the Cherax destructor-complex were investigated using a dataset comprising sequences from four mitochondrial gene regions: the large subunit rRNA (16S rRNA), cytochrome oxidase I (COI), adenosine triphosphatase 6 (ATPase 6), and cytochrome oxidase III (COIII). A total of 1602 bp was obtained, and a combined analysis of the data produced a tree with strong support (bootstrap values 94–100%) for three divergent lineages, verifying the phylogenetic hypotheses of relationships within the C. destructor species-complex suggested in previous studies. Overall, sequences from the 16S rRNA gene showed the least variation compared to those generated from protein coding genes, which presented considerably greater levels of divergence. The level of divergence within C. destructor was found to be greater than that observed in other species of freshwater crayfish, but interspecific variation among species examined in the present study was similar to that reported previously.

Transient changes in muscle high-energy phosphates during moderate exercise

1993 ◽  
Vol 75 (2) ◽  
pp. 648-656 ◽  
Author(s):  
G. D. Marsh ◽  
D. H. Paterson ◽  
J. J. Potwarka ◽  
R. T. Thompson
Keyword(s):  
Oxygen Consumption ◽  
Steady State ◽  
Recovery Period ◽  
High Energy ◽  
Second Order ◽  
Moderate Intensity ◽  
High Energy Phosphates ◽  
Order Model ◽  
Time Constants ◽  
First Order

The purpose of this study was to use 31P-nuclear magnetic resonance spectroscopy to examine changes in wrist flexor muscle metabolism during the transitions from rest to steady-state exercise (on-transient) and back to rest (off-transient). Five healthy young males (mean age 25 +/- 2 yr) performed a series of square-wave exercise tests, each consisting of 5 min of moderate-intensity work followed by a 5-min recovery period. The subjects repeated this protocol six times, and each individual's results were pooled before analysis. ATP and intracellular pH did not change significantly during exercise or recovery. Phosphocreatine (PCr) declined progressively at the onset of exercise, reaching a plateau after approximately 2 min. A reciprocal increase in Pi occurred during the onset of exercise. During the recovery period PCr was resynthesized, whereas Pi returned to resting levels. The data were plotted as a function of time and fit with both first- and second-order exponential growth or decay models; however, the second-order model did not significantly improve the fit of the data. Time constants for the first-order model of the on- and off-transient responses for both PCr and Pi were approximately 30 s. These values are nearly identical to the time constants for oxygen consumption during submaximal exercise that have been reported previously by several authors. The results of this study show that the metabolism of muscle PCr during steady-state exercise and recovery can be accurately described by a monoexponential model and, further, suggest that a first-order proportionality exists between metabolic substrate utilization and oxygen consumption.

Effects of extreme pH on the physiology of the Australian 'yabby' Cherax destructor: acute and chronic changes in haemolymph oxygen levels, oxygen consumption and metabolic levels

1995 ◽  
Vol 198 (2) ◽  
pp. 409-418 ◽  
Author(s):  
B Ellis ◽  
S Morris
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Oxygen Transport ◽  
Consumption Rate ◽  
Lactate Concentration ◽  
Acid Water ◽  
Freshwater Crayfish ◽  
Glucose Levels ◽  
Cherax Destructor ◽  
Growth And Reproduction

Respiration and metabolism of the freshwater crayfish Cherax destructor were investigated with respect to the acidification and alkalization of its environment. Crayfish were exposed for up to 504 h (21 days) to pH 4.5, pH 7.1 (control) or pH 8.0 water and oxygen consumption rate, haemolymph oxygen transport and haemolymph glucose and lactate concentrations were determined. The effect of reducing environmental [Ca2+] in acid water from 500 to 50 µmol l-1 was also examined. In acid water (500 µmol l-1 Ca2+), oxygen uptake by Cherax was reduced by 79 % after 504 h (21 days) compared with 'control' animals (pH 7.1, 500 µmol l-1 Ca2+). Haemolymph lactate concentration (mean 0.6 mmol l-1) remained constant, indicating that anaerobiosis was not important, while glucose concentrations were regulated within the range of control values (0.32±0.01 mmol l-1). The arterial-venous CO2 difference of Cherax haemolymph decreased after 288 h and PaO2 increased from 11.1±0.5 mmHg to 42.4±1.0 mmHg between 96 h and 288 h. Decreased oxygen uptake and delivery without compensatory increases in anaerobiosis or glucose levels describe a hypometabolic response to low pH. The hypometabolic response of Cherax was greater in alkaline water as shown by a 53 % reduction in O2 uptake rate compared with a 44 % reduction in acid-exposed (500 µmol l-1 Ca2+) animals after 96 h. This decrease in M(dot)O2 of alkaline-exposed animals was correlated with decreased haemolymph glucose levels (from 0.32±0.01 at 0 h to 0.06±0.01 mmol l-1 at 96 h). Lowering the [Ca2+] of the water both increased the magnitude of the effects of acid exposure and elicited further changes in haemolymph oxygen transport. The maintenance of high haemolymph PO2 during pH stress appears to reduce the involvement of haemocyanin, since this promotes decreased a­v CO2. Hypometabolism probably permits Cherax to conserve resources that might otherwise be used, however, for growth and reproduction. The implications for the fitness of the animal are discussed.

Physical Properties, Sensory Receptors and Tactile Reflexes of the Antenna of the Australian Freshwater Crayfish Cherax Destructor

1989 ◽  
Vol 141 (1) ◽  
pp. 197-217 ◽  
Author(s):  
DAVID C. SANDEMAN
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Sensory Nerve ◽  
The Body ◽  
Mechanical Resistance ◽  
Freshwater Crayfish ◽  
Sensory Axons ◽  
Cherax Destructor ◽  
The Individual ◽  
Australian Freshwater

1. The antennal flagellum of the crayfish Cherax destructor is very flexible, tapered and is almost as long as the body in mature animals. It consists of a series of short segments, oval in cross-section, that take the form of flattened rings at the base and slender tubes at the tip. There are no muscles in the flagellum. 2. The flagellum's mechanical resistance to being bent is not the same in all directions. It is most easily bent dorsally and least easily bent medially, when held stretched out horizontally in front of the animal. The resistance to bending is 10 times less than that of Astacus. 3. The individual segments of the flagellum form curved articulating surfaces that may assist in reducing torsional movement of the flagellum when it is bent and, together with the tapered form, provide the flagellum with unique mechanical properties. 4. Four main types of hairs are found on the flagellum. They are distributed in a specific manner, and total about 7000 hairs on the flagellum of a mature animal. Cross-sections through the sensory nerve reveal only about 2000 axons. Methylene blue applied to fresh preparations stains dendrites to all smooth hairs but never to procumbent feathered hairs. 5. Physiological recordings from the sensory axons of the flagellar nerve allowed the characterization of the sensory hair response to displacement. Recordings were also made from slowly adapting receptors, sensitive to bending the flagellum in particular directions, but not related to mechanoreceptive hairs. 6. Intracellular recordings from identified extensor and flexor motoneurones revealed the ordered projection of the inputs from the receptor hairs, and also provided a model that correlates specific receptor inputs with particular antennal reflexes, and links the unique mechanical properties of the flagellum with the detection of the distance of near objects.

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