High Metabolic Energy Research Articles

Changes of proteome and phosphoproteome trigger embryo–larva transition of honeybee worker (Apis mellifera ligustica)

The development of the last day embryo to the first instar larva is an essential process in the honeybee life cycle. However, the molecular mechanism of this life transition is still unknown. The proteome and phosphoproteome of last day embryos (72 h) and first instar larvae (24h, post hatching) were analyzed using 2-DE, multiplex fluorescent staining, mass spectrometry, bioinformatics, and qRT-PCR. Sixty-five proteins and 34 phosphoproteins changed their expression across the shift of embryos to larvae. The embryo stronger expression of proteins related to energy metabolism, development and amino acid metabolism suggests its high metabolic energy demand during active embryogenesis. While, the newly hatched larvae escalated the expression of proteins related to cytoskeleton, biosynthesis, protein folding, fatty acid and oxidative metabolism, particularly the higher phosphorylation of cytoskeleton and biosynthesis indicates their roles to ensure the fast growing larvae. These differences in protein expression level illustrate that specific protein functions are restricted to particular developmental stage. Our data suggest the essential changes of proteome and phosphoproteome to trigger the transition of embryo to larvae. This unravels the molecular event behind the first life cycle transition of honeybees and is potentially helpful for future reverse genetic studies in this model insect.

Temperature-dependent alterations in metabolic enzymes and proteins of three ecophysiologically different species of earthworms

The effects of varying temperatures (12 - 44° C) on the specific activity of cytoplasmic malate dehydrogenase ((cMDH), mitochondrial malate dehydrogenase (mMDH) and lactate dehydrogenase (LDH) of some earthworms (Metaphire posthuma, Perionyx sansibaricus and Lampito mauritii) were studied. The effects of different temperatures on supernatant and mitochondrial protein contents were also investigated. The specific activities of cMDH, mMDH and LDH of the earthworms decreased gradually as a function of increasing temperature from 12 to 44°C. Higher metabolic energy was needed to maintain the activity at low temperatures. Hence, the earthworms showed increased enzyme specific activity at low temperatures. However, the protein content increased upto 28°C. Afterwards, with the increase in the temperature from 28 to 42°C, the proteins in the earthworms showed a significant decrease. The temperature-associated changes in the protein content could be explained by the fact that protein synthesizing capacity was hampered above and below the optimum temperature range. The most pronounced effects of varying temperatures were on P. sansibaricus. It might be due to the epigeic nature of the earthworm species. Then minimum effect was on the endogeic earthworm M. posthuma. Virtually, the differences in the enzymes physiology were associated with the differences in the ecological categories of the earthworms. This clearly demonstrate a possible link between the physiology and ecology at aerobic (cMDH, mMDH) and anaerobic (LDH) levels in the tropical earthworms.

Effect of Harvest Treatment on Biochemical Properties of Farmed Chinook Salmon (Oncorhynchus tshawytscha) Tissue during Frozen and Thawed Storage

Two different harvest procedures were employed to investigate whether the method of harvest has an effect upon deteriorative processes that occur during the frozen storage of Chinook salmon (Oncorhynchus tshawytscha) white muscle tissue. These 2 harvest methods, termed "rested"--involving sedation with the aquatic anesthetic AQUI-S and "exercised"--a simulated conventional harvest not involving sedation, contrasted levels of activity of the animal prior to and upon slaughter. Rested and exercised harvesting protocols produced tissue in significantly different postmortem physiological states prior to freezing. Rested, postharvest tissue maintained high metabolic energy stores of ATP and glycogen within the tissue, with low concentrations of tissue and plasma lactate. Exercised tissue exhibited near depleted concentrations of ATP and glycogen and a marked lactate accumulation. In both treatments, no significant change in metabolite levels was seen over a 6-mo storage period at -19 degrees C when tissue was frozen immediately postharvest. Transfer of tissue from frozen temperatures (-80 and -19 degrees C), to refrigerated (-1 and +4 degrees C, respectively) resulted in rapid glycolysis, depleting tissue ATP and glycogen stores and increasing tissue lactate concentrations. Metabolic activity was more significant in rested tissue owing to the larger concentrations of metabolic energy stores and occurred at temperatures between -3 and -1.5 degrees C. During frozen storage (-19 degrees C), there was an increase in the secondary lipid oxidation product TBARS, but harvest treatment had no effect. However, following transfer from frozen to refrigerated (+4 and -1 degrees C) storage, rested tissue showed a significant ability to retard the development of TBARS products.

Wide home ranges for widely foraging lizards

Space usage by animals may be influenced by a range of factors. In this study we investigate whether foraging behaviour affects the home range size of lizards. Two distinct tactics of foraging have been recognized in predators: sit-and-wait foraging (SW) and active foraging (AF). Foraging activity level of a data set of lizard species, mainly compiled from literature, is compared with their home range sizes. Two opposite predictions can be made about foraging in connection with home range area: on the one hand, SW species may exhibit larger home ranges due to their mating system; on the other hand, AF species have higher metabolic energy and thus food requirements and can be expected to have larger home ranges that have to yield this food. This study shows that percentage of the time moving (as an index of foraging mode) correlates positively with home range, even after correcting for body mass, and these patterns remain when phylogenetic relationships are taken into account. We thus conclude that home range areas parallel activity levels in lizards.

Aging Effects on the Metabolic and Cognitive Energy Cost of Interlimb Coordination

Many everyday motor tasks have high metabolic energy demands, and some require extended practice to learn the required coordination between limbs. Eight older (73.1 +/- 4.4 years) and 8 younger (23.3 +/- 5.9) men practiced a high-energy two-hand coordination task with both 180 degrees and 90 degrees target relative phase. The older group showed greater performance error in both conditions, and performance at 90 degrees was strongly attracted to antiphase coordination (180 degrees). In a retention test one week following the acquisition trials, the older group had learned the 180 degrees condition but did not learn the 90 degrees condition. Metabolic energy cost was not different between groups, but the older men showed higher heart rate and both conditions imposed greater cognitive demands as revealed in auditory probe reaction time. Older adults' motor learning may be inhibited by elevated heart rate at the same oxygen cost, increased cognitive cost, and an attraction toward more established low-energy in-phase or antiphase coordination.

Effect of Tiangui recipe on serum leptin and pituitary gonadotropin in androgen-sterilized ratson serum leptin and pituitary gonadotropin in androgen-sterilized rats

Objective: To explore the effect of Tiangui Recipe (TGR) on obesity and reproductive function in androgen-sterilized rats (ASR).Methods: ASR model was established by subcutaneous injection of testosterone propionate to SD female rats at the age of 9 days. Change of serum leptin, follicular stimulating hormone (FSH) and luteinizing hormone (LH) in model rats aged 115 days before and after feeding them with TGR was measured by radioimmunoassay (RIA). Meanwhile, criteria of energy state, including diurnal food intake, retroperitoneal fat depot weight and body weight, were measured and evaluated.Results: ASR had the characteristics of high metabolic rate, energy imbalance and obesity. Serum level of leptin increased and FSH, LH decreased significantly (P<0.01) in model rats as compared with the normal rats. Significant positive correlation between leptin level and body weight (r=0.8977, P<0.001) was observed, and negative correlation was seen between FSH, LH and leptin (r = -0.7517, P<0.001; r= -0.8444, P<0.001, respectively). The endocrine changes of ASR all returned to normal range after the TGR treatment.Conclusion: Obesity and concerned hypogonadotrophic hypogonadal anovulation were expressed in ASR. TGR may play an important role in reducing weight and inducing ovulation.

New and old in pediatric exercise physiology.

Researchers in pediatric exercise physiology sometimes overlook previously published findings that are similar, or even identical, to their own. The intent of this review is to provide examples for the above pattern. These examples relate to the following topics: 1) is the O2 uptake plateau a necessary criterion for the establishment of maximal O2 uptake in children? 2) children's greater utilization of fat during prolonged exercise, 3) children's lower maximal blood lactate levels, 4) the higher metabolic energy cost of locomotion in children and the possible causes for this phenomenon, and 5) the lower cardiac output and stroke volume in children, at any given O2 uptake.

Effect of Tiangui Recipe on serum leptin and pituitary gonadotropin in androgen-sterilized rats

To explore the effect of Tiangui Recipe (TGR) on obesity and reproductive function in androgen-sterilized rats (ASR). ASR model was established by subcutaneous injection of testosterone propionate to SD female rats of 9 days age. Change of serum leptin, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in model rats of 115 days old before and after feeding TGR was measured by radioimmunoassay (RIA). Meanwhile, criteria of energy state, including diurnal food intake, retroperitoneal fat depot weight and body weight, were measured and evaluated. ASR had the characteristics of high metabolic rate, energy imbalance and obesity. Serum level of leptin increased and FSH, LH decreased significantly (P < 0.01) in model rats as compared with the normal rats. Significant positive correlation between leptin level and body weight (r = 0.8977, P < 0.001) was observed, and negative correlation was seen between FSH, LH and leptin (r = -0.7517, P < 0.001; r = -0.8444, P < 0.001, respectively). The endocrinous changes of ASR all returned to normal range after the TGR treatment. Obesity and concerned hypogonadotropic hypogonadal anovulation were expressed in ASR. TGR may play an important role in reducing weight and inducing ovulation.

From environmental fluctuations and energy availability to evolutionary change and speciation

Evolutionary patterns can be considered in terms of two interacting continuums (a) the magnitude of environmental fluctuations of physical variables especially climatic, and (b) the availability of metabolic energy beyond basic needs for maintenance and survival (Parsons, 1991) so giving four extreme combinations:(1) widely fluctuating environments, low metabolic energy availability. This situation is a feature of species borders where the energetic costs of environmental perturbations restrict normal physiological processes so that ecological range expansions are precluded. Provided extinctions do not occur, species would alter their ranges to track longer term climatic changes as described in the historical and fossil records.(2) widely fluctuating environments, high metabolic energy availability. This combination favors opportunists and colonists. Furthermore, following a relaxation of stress intensity after a mass extinction there could be a burst of speciation in such generalist species.(3) stable environments, low metabolic energy availabilty. This combination represents deep sea and cave environments where low metabolic rate is an adaptation to accomodate stresses such as anoxia and low resource availability. Consequently the capacity for evolutionary change is low in these habitats which tend to contain relict species.(4) stable environments, high metabolic energy availability. On energetic grounds speciation is theoretically possible, but high vulnerability to any stressful perturbation would be restrictive in practice since some stress is the norm in natural populations.The potential for evolutionary change and speciation is low in these four extremes, however in intermediate habitats the potential is higher as implied in (2) when stress intensity is relaxed. The intermediate habitats would be characterized by moderately fluctuating environments where the metabolic cost of stress would not preclude adaptive change. Furthermore, the stress levels in such habitats should lead to sufficient underlying genetic variability to be permissive of adaptive responses to environmental change (Parsons, 1991). This paradigm may apply to speciation in tropical rain forests. A fossil analogy would be marine invertebrates in frequently disturbed onshore habitats.