Long-term fasting and realimentation in hypogean and epigean isopods: a proposed adaptive strategy for groundwater organisms

2002 ◽  
Vol 205 (14) ◽  
pp. 2079-2087 ◽  
Author(s):  
Frédéric Hervant ◽  
David Renault
Keyword(s):  
Metabolic Response ◽  
Large Body ◽  
Adaptive Strategy ◽  
Energy System ◽  
Adaptive Responses ◽  
Rapid Restoration ◽  
Surface Dwelling ◽  
Unpredictable Environment ◽  
Lipid Stores

SUMMARYThe effects of long-term fasting and subsequent refeeding on digestive physiology and energy metabolism were investigated in a subterranean aquatic crustacean, Stenasellus virei, and in a morphologically similar surface-dwelling species, Asellus aquaticus. Metabolic response to food deprivation was monophasic in A. aquaticus, with an immediate,large decrease in all energy reserves. In contrast, S. vireidisplayed three successive periods of phosphageno-glucidic, lipidic and,finally, proteo-lipidic-dominant catabolism over the course of the nutritional stress. To represent the responses of subterranean crustaceans to food stress and renutrition, a sequential energy strategy was hypothesized, suggesting that four successive phases (called stress, transition, adaptation and recovery) can be distinguished. Based on these results, a general adaptive strategy for groundwater organisms was proposed. Their remarkable resistance to long-term fasting may be partly explained by (1) a depressed metabolism,during which they mainly subsist on lipid stores, (2) a prolonged state of glycogen- and protein-sparing, (3) low energetic requirements and (4) large body stores. In addition, these groundwater species displayed high recovery abilities during refeeding, showing an optimal utilization of available food and a rapid restoration of their body reserves. These adaptive responses might be considered for numerous subterranean organisms as an efficient energy-saving strategy in a harsh and unpredictable environment where fasting(and/or hypoxic) periods of variable duration alternate with sporadic feeding events (and/or normoxic periods). Therefore, food-limited and/or hypoxia-tolerant groundwater species appear to be good examples of animals representing a low-energy system.

scholarly journals Behavioural, physiological and metabolic responses to long-term starvation and refeeding in a blind cave-dwelling (Proteus anguinus) and a surface-dwelling (Euproctus asper) salamander

2001 ◽  
Vol 204 (2) ◽  
pp. 269-281 ◽  
Author(s):  
F. Hervant ◽  
J. Mathieu ◽  
J. Durand
Keyword(s):  
Food Deprivation ◽  
Metabolic Response ◽  
Energy System ◽  
Energy Reserves ◽  
Energy Strategy ◽  
Quick Recovery ◽  
Proteus Anguinus ◽  
Surface Dwelling ◽  
Blind Cave

The effects of long-term starvation and subsequent refeeding on haematological variables, behaviour, rates of oxygen consumption and intermediary and energy metabolism were studied in morphologically similar surface- and cave-dwelling salamanders. To provide a hypothetical general model representing the responses of amphibians to food stress, a sequential energy strategy has been proposed, suggesting that four successive phases (termed stress, transition, adaptation and recovery) can be distinguished. The metabolic response to prolonged food deprivation was monophasic in the epigean Euproctus asper (Salamandridae), showing an immediate, linear and large decrease in all the energy reserves. In contrast, the hypogean Proteus anguinus (Proteidae) displayed successive periods of glucidic, lipidic and finally lipido-proteic-dominant catabolism during the course of food deprivation. The remarkable resistance to long-term fasting and the very quick recovery from nutritional stress of this cave organism may be explained partly by its ability to remain in an extremely prolonged state of protein sparing and temporary torpor. Proteus anguinus had reduced metabolic and activity rates (considerably lower than those of most surface-dwelling amphibians). These results are interpreted as adaptations to a subterranean existence in which poor and discontinuous food supplies and/or intermittent hypoxia may occur for long periods. Therefore, P. anguinus appears to be a good example of a low-energy-system vertebrate.

scholarly journals Comparative study on the metabolic responses of subterranean and surface-dwelling amphipods to long-term starvation and subsequent refeeding

1999 ◽  
Vol 202 (24) ◽  
pp. 3587-3595
Author(s):  
F. Hervant ◽  
J. Mathieu ◽  
H. Barre
Keyword(s):  
Food Deprivation ◽  
Metabolic Response ◽  
Starvation Period ◽  
Competitive Advantages ◽  
Adaptive Responses ◽  
Gammarus Fossarum ◽  
Surface Dwelling ◽  
Subterranean Species ◽  
Large Decline

The effects of long-term starvation and subsequent refeeding on intermediary and energy metabolism were investigated in two subterranean aquatic crustaceans, Niphargus rhenorhodanensis and Niphargus virei, and in a morphologically similar surface-dwelling species, Gammarus fossarum. The metabolic response to prolonged food deprivation was monophasic in G. fossarum, showing an immediate, linear and large decline in all of the energy reserves. In contrast, both subterranean organisms displayed successive periods of glucidic, proteo-glucidic then lipidic-dominant catabolism during food deprivation. In both subterranean species, lipids (51 % of the energy consumed during a 180-day starvation period) and proteins (44 %) were the most metabolized substrates in terms of total energy, whereas glycogen (5 %) contributed little energy. G. fossarum displayed a different energetic strategy: proteins comprised 56 % of the energy losses during a 28-day starvation period, total lipids some 39 % and glycogen reserves only 5 %. We propose an energy strategy for food-limited subterranean crustaceans involving the possession of (1) higher amounts of stored arginine phosphate, triglycerides and glycogen and (2) lower utilization rates of stored metabolites than G. fossarum and numerous other surface-dwelling crustaceans, making the fueling of food deprivation possible for a longer time. In addition, these species had a faster and more efficient assimilation of available nutrients during recovery from food deprivation, enabling preparation for a new nutritional stress. These specific adaptive responses might be considered, for N. virei and N. rhenorhodanensis, as an efficient energy-saving strategy for an environment where extended starvation periods alternate with sporadic feeding events, therefore improving their competitive advantages.

scholarly journals Metabolic response of Botryococcus braunii to high bicarbonate dosages and other conditions: analysis of photosynthetic performance, productivity, and lipidomic profile

2021 ◽  
Author(s):  
Néstor David Giraldo ◽  
Sandra Marcela Correa ◽  
Andrés Arbeláez ◽  
Felix L. Figueroa ◽  
Rigoberto Ríos-Estepa ◽  
...  
Keyword(s):  
Nutrient Limitation ◽  
Metabolic Response ◽  
Neutral Lipids ◽  
Biomass Productivity ◽  
Botryococcus Braunii ◽  
Photosynthetic Performance ◽  
Lipid Productivity ◽  
Cellular Growth ◽  
Adaptive Responses ◽  
Nitrogen And Phosphorus

AbstractIn this study the metabolic responses of Botryococcus braunii were analyzed upon different inorganic carbon dosages and nutrient limitation conditions in terms of lipid and biomass productivity, as well as photosynthetic performance. The nutritional schemes evaluated included different levels of sodium bicarbonate and nitrogen and phosphorus starvation, which were contrasted against standard cultures fed with CO2. Bicarbonate was found to be an advantageous carbon source since high dosages caused a significant increase in biomass and lipid productivity, in addition to an enhanced photosynthetic quantum yield and neutral lipids abundance. This contrasts to the commonly used approach of microalgae nutrient limitation, which leads to high lipid accumulation at the expense of impaired cellular growth, causing a decline in overall lipid productivity. The lipidome analysis served to hypothesize about the influence of the nutritional context on B. braunii structural and storage lipid metabolism, besides the adaptive responses exhibited by cells that underwent nutrient stress.

scholarly journals Advancement in long-distance bird migration through individual plasticity in departure

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jesse R. Conklin ◽  
Simeon Lisovski ◽  
Phil F. Battley
Keyword(s):  
Bird Migration ◽  
Population Level ◽  
Breeding Site ◽  
Environmental Constraints ◽  
Adaptive Responses ◽  
Long Distance ◽  
Direct Observations ◽  
Breeding Resources ◽  
Plastic Responses

AbstractGlobally, bird migration is occurring earlier in the year, consistent with climate-related changes in breeding resources. Although often attributed to phenotypic plasticity, there is no clear demonstration of long-term population advancement in avian migration through individual plasticity. Using direct observations of bar-tailed godwits (Limosa lapponica) departing New Zealand on a 16,000-km journey to Alaska, we show that migration advanced by six days during 2008–2020, and that within-individual advancement was sufficient to explain this population-level change. However, in individuals tracked for the entire migration (50 total tracks of 36 individuals), earlier departure did not lead to earlier arrival or breeding in Alaska, due to prolonged stopovers in Asia. Moreover, changes in breeding-site phenology varied across Alaska, but were not reflected in within-population differences in advancement of migratory departure. We demonstrate that plastic responses can drive population-level changes in timing of long-distance migration, but also that behavioral and environmental constraints en route may yet limit adaptive responses to global change.

scholarly journals Long-Lasting Hyperexcitability Induced by Depolarization in the Absence of Detectable Ca2+ Signals

2009 ◽  
Vol 101 (3) ◽  
pp. 1351-1360 ◽  
Author(s):  
Kumud K. Kunjilwar ◽  
Harvey M. Fishman ◽  
Dario J. Englot ◽  
Roger G. O'Neil ◽  
Edgar T. Walters
Keyword(s):  
Protein Synthesis ◽  
Neuronal Injury ◽  
Adaptive Responses ◽  
Neuronal Responses ◽  
Local Protein Synthesis ◽  
Neuronal Viability ◽  
Nerve Ganglion ◽  
Dissociated Cell Culture ◽  
Activity Dependent

Learning and memory depend on neuronal alterations induced by electrical activity. Most examples of activity-dependent plasticity, as well as adaptive responses to neuronal injury, have been linked explicitly or implicitly to induction by Ca2+ signals produced by depolarization. Indeed, transient Ca2+ signals are commonly assumed to be the only effective transducers of depolarization into adaptive neuronal responses. Nevertheless, Ca2+-independent depolarization-induced signals might also trigger plastic changes. Establishing the existence of such signals is a challenge because procedures that eliminate Ca2+ transients also impair neuronal viability and tolerance to cellular stress. We have taken advantage of nociceptive sensory neurons in the marine snail Aplysia, which exhibit unusual tolerance to extreme reduction of extracellular and intracellular free Ca2+ levels. The axons of these neurons exhibit a depolarization-induced memory-like hyperexcitability that lasts a day or longer and depends on local protein synthesis for induction. Here we show that transient localized depolarization of these axons in an excised nerve–ganglion preparation or in dissociated cell culture can induce short- and intermediate-term axonal hyperexcitability as well as long-term protein synthesis–dependent hyperexcitability under conditions in which Ca2+ entry is prevented (by bathing in nominally Ca2+ -free solutions containing EGTA) and detectable Ca2+ transients are eliminated (by adding BAPTA-AM). Disruption of Ca2+ release from intracellular stores by pretreatment with thapsigargin also failed to affect induction of axonal hyperexcitability. These findings suggest that unrecognized Ca2+-independent signals exist that can transduce intense depolarization into adaptive cellular responses during neuronal injury, prolonged high-frequency activity, or other sustained depolarizing events.

scholarly journals Analysing long-term opportunities for offshore energy system integration in the Danish North Sea

2021 ◽  
pp. 100067
Author(s):  
Russell McKenna ◽  
Matteo D'Andrea ◽  
Mario Garzón González
Keyword(s):  
North Sea ◽  
System Integration ◽  
Energy System

scholarly journals Evaluating long-term model-based scenarios of the energy system

2020 ◽  
Vol 32 ◽  
pp. 100551
Author(s):  
Matthew Binsted ◽  
Gokul Iyer ◽  
Ryna Cui ◽  
Zarrar Khan ◽  
Kalyn Dorheim ◽  
...  
Keyword(s):  
Energy System ◽  
Model Based ◽  
Term Model

MIXED CONFORMING ELEMENTS FOR THE LARGE-BODY LIMIT IN MICROMAGNETICS

2013 ◽  
Vol 24 (01) ◽  
pp. 113-144 ◽  
Author(s):  
MARKUS AURADA ◽  
JENS M. MELENK ◽  
DIRK PRAETORIUS
Keyword(s):  
Mixed Finite Element ◽  
Large Body ◽  
Mixed Finite Element Method ◽  
Adaptive Strategy ◽  
Posteriori Error ◽  
Higher Order ◽  
Three Dimensions ◽  
Macroscopic Model ◽  
Error Estimator ◽  
Discrete Problem

We introduce a stabilized conforming mixed finite element method for a macroscopic model in micromagnetics. We show well-posedness of the discrete problem for higher order elements in two and three dimensions, develop a full a priori analysis for lowest order elements, and discuss the extension of the method to higher order elements. We introduce a residual-based a posteriori error estimator and present an adaptive strategy. Numerical examples illustrate the performance of the method.

Improved Representation of the European Power Grid in Long Term Energy System Models: Case Study of JRC-EU-TIMES

2015 ◽  
pp. 201-222 ◽  
Author(s):  
Wouter Nijs ◽  
Sofia Simoes ◽  
Alessandra Sgobbi ◽  
Pablo Ruiz-Castello ◽  
Christian Thiel ◽  
...  
Keyword(s):  
Power Grid ◽  
Energy System ◽  
System Models ◽  
Term Energy

scholarly journals Is “transgenerational response” a hidden cause of failed corporate turnarounds and chronic underperformance?

2017 ◽  
Vol 45 (3) ◽  
pp. 23-29
Author(s):  
John Oliver
Keyword(s):  
Financial Performance ◽  
Case Studies ◽  
Corporate Culture ◽  
Ceo Turnover ◽  
Business Leaders ◽  
Adaptive Responses ◽  
Content Type ◽  
Organizational Policies ◽  
And Performance

Purpose CEO turnover and chronic corporate underperformance are examined through the lens of Transgenerational Response. Design/methodology/approach The criteria for investigating Transgenerational Response in corporations consisted of identifying a Critical Corporate Incident, the number of corporate generations and the resultant corporate financial performance. Findings The evidence presented in the case studies illustrates how a Critical Corporate Incident has produced the consequential effect of chronic financial performance in the years following the incident. Research limitations/implications These case studies have not presented the “actual” adaptive responses, inherited attitudes and behaviours that have subsequently embedded themselves in a new corporate culture, post the Critical Corporate Incident, to the detriment of the long-term health and performance of each firm. Practical implications Examining CEO turnover and chronic corporate underperformance through the lens of Transgenerational Response means that business leaders can identify how a historic event has affected the performance of their firm in subsequent generations. With this knowledge in hand, they will be able to examine the inherited attitudes and behaviours, organizational policies, strategy and adaptive cultural routines that have combined to consolidate the firms chronic under performance. Originality/value This is a highly original, evidence based, idea that has the potential to reshape our current understanding of CEO turnover and underperforming firms. It will help business leaders identify how a historic event has affected the performance of a firm in subsequent generations.

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