Tyre wear particles may be the largest source of microplastic to the natural environment, yet information on their biological impacts is inadequate. Two key estuarine invertebrates; the clam ...Scrobicularia plana and the ragworm Hediste diversicolor were exposed to 10% tyre particles in sediment for three days. Both species consumed the particles, although S. plana consumed 25x more than H. diversicolor (967 compared with 35 particles.g−1 wet weight, respectively). We then investigated the impact of 21 days exposure to different concentrations of tyre particles in estuarine sediments (0.2, 1, and 5% dry weight sediment) on aspects of the health of S. plana and H. diversicolor. Reductions in feeding and burial rates were observed for S. plana but not H. diversicolor, whilst both species showed a decrease in protein content in response to the greatest tyre particle concentration (5%), linked to an 18% decrease in energy reserves for H. diversicolor. Five percent tyre particle exposure led to an increase in total glutathione in the tissues of H. diversicolor, whilst lipid peroxidation decreased in the digestive glands of S. plana, possibly due to an increase in cell turnover. This study found that S. plana's health was impacted at lower concentrations than H. diversicolor, likely due to its consumption of large quantities of sediment. At the high exposure concentration (5%), the health of both invertebrates was impacted. This study did not separate the effects caused by the microplastic particles versus the effects of the chemical additives leaching from these particles, but our results do indicate that future studies should investigate effects in isolation and in combination, to determine the main drivers of toxicity.
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•Tyre wear particles are a contaminant of emerging concern.•Scrobicularia plana consumed more tyre particles than Hediste diversicolor.•Both burrowing and feeding rate were impaired in S. plana.•High concentrations of tyre particles decreased protein content in both species.•Antioxidant capacity (cellular glutathione) was upregulated in H. diversicolor.
The causes of the physiological effects of microplastic pollution, potentially harming reef-building corals, are unclear. Reasons might include increased energy demands for handling particles and ...immune reactions. This study is among the first assessing the effects of long-term microplastic exposure on coral physiology at realistic concentrations (200 polyethylene particles L−1). The coral species Acropora muricata, Pocillopora verrucosa, Porites lutea, and Heliopora coerulea were exposed to microplastics for 11 months, and energy reserves, metabolites, growth, and photosymbiont state were analyzed. Results showed an overall low impact on coral physiology, yet species-specific effects occurred. Specifically, H. coerulea exhibited reduced growth, P. lutea and A. muricata showed changes in photosynthetic efficiency, and A. muricata variations in taurine levels. These findings suggest that corals may possess compensatory mechanisms mitigating the effects of microplastics. However, realistic microplastic concentrations only occasionally affected corals. Yet, corals exposed to increasing pollution scenarios will likely experience more negative impacts.
•Coral physiology remained largely unaffected by long-term microplastic exposure.•Microplastics occasionally had subtle, species-specific effects on coral physiology.•Increased taurine levels may initiate the translocation of carbon fixation products.•Reduced growth may be a trade-off mitigating the increased energy needs.•Altered photosynthetic efficiency may provide additional energy for compensation.
Immune function is an energetically costly physiological activity that potentially diverts calories away from less immediately essential life tasks. Among developing organisms, the allocation of ...energy toward immune function may lead to tradeoffs with physical growth, particularly in high-pathogen, low-resource environments. The present study tests this hypothesis across diverse timeframes, branches of immunity, and conditions of energy availability among humans. Using a prospective mixed-longitudinal design, we collected anthropometric and blood immune biomarker data from 261 Amazonian forager-horticulturalist Shuar children (age 4–11 y old). This strategy provided baseline measures of participant stature, s.c. body fat, and humoral and cell-mediated immune activity as well as subsample longitudinal measures of linear growth (1 wk, 3 mo, 20 mo) and acute inflammation. Multilevel analyses demonstrate consistent negative effects of immune function on growth, with children experiencing up to 49% growth reduction during periods of mildly elevated immune activity. The direct energetic nature of these relationships is indicated by (i) the manifestation of biomarker-specific negative immune effects only when examining growth over timeframes capturing active competition for energetic resources, (ii) the exaggerated impact of particularly costly inflammation on growth, and (iii) the ability of children with greater levels of body fat (i.e., energy reserves) to completely avoid the growth-inhibiting effects of acute inflammation. These findings provide evidence for immunologically and temporally diverse body fat-dependent tradeoffs between immune function and growth during childhood. We discuss the implications of this work for understanding human developmental energetics and the biological mechanisms regulating variation in human ontogeny, life history, and health.
The fat body plays major roles in the life of insects. It is a dynamic tissue involved in multiple metabolic functions. One of these functions is to store and release energy in response to the energy ...demands of the insect. Insects store energy reserves in the form of glycogen and triglycerides in the adipocytes, the main fat body cell. Insect adipocytes can store a great amount of lipid reserves as cytoplasmic lipid droplets. Lipid metabolism is essential for growth and reproduction and provides energy needed during extended nonfeeding periods. This review focuses on energy storage and release and summarizes current understanding of the mechanisms underlying these processes in insects.
•Laboratory study on field-relevant exposure to mosquito control agent Bti.•Long-term exposure alters sensitivity of populations to Bti.•Phenotypic adaptation of populations in emergence time and ...nutrient content.•Reduced effect of Bti on lipid content of pre-exposed populations.•Food quality affects emergence time, protein and lipid content.
Insects with aquatic larval and terrestrial adult life stages are a key component of coupled aquatic-terrestrial ecosystems. Thus, stressors applied to water bodies adversely affecting those larvae have the potential to influence the riparian zone through altered emergence, with differences in prey availability, timing, or nutrition. In this study, the common model organism Chironomus riparius, a species of Chironomidae (Diptera), was used. This selection was further motivated by its wide distribution in European freshwaters and its importance as prey for terrestrial predators. A stressor of high importance in this context is the globally used mosquito control agent Bacillus thuringiensis var. israelensis (Bti) which has been shown to affect Chironomidae. Here, we investigated the ability of chironomid populations to adapt to a regularly applied stressor, leading to a reduced impact of Bti. Therefore, the initial sensitivity of laboratory populations of C. riparius was investigated under the influence of field-relevant Bti treatments (three doses × two application days) and different food sources (high-quality TetraMin vs. low-quality Spirulina). Following a chronic exposure to Bti over six months, the sensitivity of pre-exposed and naïve populations was re-evaluated. Food quality had a strong impact on emergence timing and nutrient content. In addition, alterations in emergence time as well as protein and lipid contents of chronically exposed populations indicated a selection for individuals of advantageous energetics, potentially leading to a more efficient development while combating Bti. Signs of adaptation could be confirmed in five out of 36 tested scenarios suggesting adaptation to Bti at the population level. Adaptive responses of one or several species could theoretically (via eco-evolutionary dynamics) result in a community shift, favouring the prevalence of Bti-tolerant species. (In)direct effects of Bti and the adaptive responses at both population and community levels could affect higher trophic levels and may determine the fate of meta-ecosystems.
The increasing use of rare earth elements (REEs) in electric and electronic equipment has been associated with the presence of these elements in aquatic systems. The present study aimed to evaluate ...the toxicity of two REEs, Lanthanum (La) and Gadolinium (Gd), towards the mussel species Mytilus galloprovincialis. For this, the toxicity was assessed after a short-term exposure (14 days) to an environmentally relevant concentration of each element (10 μg/L), followed by a recovery period (14 days) in the absence of any contaminant. The measured biomarkers included energy-related parameters, activity of antioxidant and biotransformation enzymes, indicators of oxidative damage, levels of oxidized glutathione and neurotoxicity. After exposure mussels accumulated more La (0.54 μg/g) than Gd (0.15 μg/g). After recovery higher concentration decrease was observed for Gd (≈40% loss) compared to La exposed mussels (≈30% loss) which may be associated with lower detoxification capacity of mussels previously exposed to La. Mussels increased their metabolism (i.e., higher electron transport system activity) only after the exposure to Gd. Exposure to La and Gd resulted into lower energy expenditure, while when both elements were removed glycogen and protein concentrations decreased to values observed in non-contaminated mussels. Antioxidant and biotransformation capacity was mainly increased in the presence of Gd. This defense response avoided the occurrence of cellular damage but still loss of redox balance was found regardless the contaminant, which was re-established after the recovery period. Neurotoxicity was only observed in the presence of Gd with no effects after the recovery period. Results showed that a short-term exposure to La and especially to Gd can exert deleterious effects that may compromise specific biochemical pathways in aquatic species, such as M. galloprovincialis, but under low concentrations organisms can be able to re-establish their biochemical status to control levels after a recovery period.
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•Higher bioaccumulation of Lanthanum (La) than Gadolinium (Gd).•Reduced energy reserves usage after exposure, with increasing use after recovery.•Higher antioxidant and biotransformation capacity after Gd exposure.•No cellular damage regardless the element and the experimental period.•Loss of redox balance after Gd exposure, restoring redox balance after recovery.
Human-induced changes in the environment have increased the number of stressors impacting aquatic organism. In the light of climate change and plastic pollution, thermal stress and microplastics (MP) ...have become two of the most intensively studied stressors in aquatic ecosystems. Previous studies, however, mostly evaluated the impacts of thermal and MP stress in isolation, thereby neglecting joint effects.
To examine the combined effects of both, we exposed the freshwater mussel Dreissena polymorpha to irregular polystyrene MP (6.4, 160, 4000, 100,000 p mL−1) at either 14, 23 or 27 °C for 14 days and analyzed mortality, mussel activity and clearance rate, energy reserves, oxidative stress and the immunological state. Further, we exposed the mussels to diatomite (natural particle equivalent, 100,000 p mL−1) at each of the three water temperatures to compare MP and natural particle toxicity.
An increase in water temperature has a pronounced effect on D. polymorpha and significantly affects the activity, energy reserves, oxidative stress and immune function. In contrast, the effects by MP are limited to a change in the antioxidative capacity without any interactive effects between MP and thermal exposure. The comparison of the MP with a diatomite exposure revealed only limited influence of the particle type on the response of D. polymorpha to high concentrations of suspended particles.
The results indicate that MPs have minor effects on a freshwater mussel compared to thermal stress, neither alone nor as interactive effect. Limited MP toxicity could be based on adaptation mechanism of dreissenids to suspended solids. Nonetheless, MP may contribute to environmental impacts of multiple anthropogenic stressors, especially if their levels increase in the future. Therefore, we suggest integrating MP into the broader context of multiple stressor studies to understand and assess their joint impacts on freshwater ecosystems.
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•Thermal stress induces stronger effects than microplastics in Dreissena polymorpha.•Thermal stress affects behavior, metabolism and immune function.•Microplastics only affect the antioxidative capacity.•Microplastic and diatomite effects only differ for the antioxidative capacity.
To maintain optimal fitness, a cell must balance the risk of inadequate energy reserve for response to a potentially fatal perturbation against the long-term cost of maintaining high concentrations ...of ATP to meet occasional spikes in demand. Here we apply a game theoretic approach to address the dynamics of energy production and expenditure in eukaryotic cells. Conventionally, glucose metabolism is viewed as a function of oxygen concentrations in which the more efficient oxidation of glucose to CO2 and H2O produces all or nearly all ATP except under hypoxic conditions when less efficient (2 ATP/ glucose vs. about 36ATP/glucose) anaerobic metabolism of glucose to lactic acid provides an emergency backup. We propose an alternative in which energy production is governed by the complex temporal and spatial dynamics of intracellular ATP demand. In the short term, a cell must provide energy for constant baseline needs but also maintain capacity to rapidly respond to fluxes in demand particularly due to external perturbations on the cell membrane. Similarly, longer-term dynamics require a trade-off between the cost of maintaining high metabolic capacity to meet uncommon spikes in demand versus the risk of unsuccessfully responding to threats or opportunities. Here we develop a model and computationally explore the cell's optimal mix of glycolytic and oxidative capacity. We find the Warburg effect, high glycolytic metabolism even under normoxic conditions, is represents a metabolic strategy that allow cancer cells to optimally meet energy demands posed by stochastic or fluctuating tumor environments.
Pubertal molt is critical for the reproductive process of mud crab Scylla paramamosain, during which female crabs molt and mate with males, and subsequently, ovarian development is initiated. Since ...fasting occurs during pubertal molt, the mechanism underlying how the internal energy reserves support crabs' survival is unclear. In this study, the hepatopancreas and ovaries were collected for metabolomics analyses. The results show 11 carbohydrate and 4 lipid metabolic pathways were remarkably modulated in hepatopancreas, suggesting carbohydrates and lipids may be the main energy reserves in hepatopancreas postmolt. Further analysis showed that the levels of glucose, glucose 6-phosphate, glucose 1-phosphate, and fructose 6-phosphate were increased, indicating glycolysis was upregulated for energy supply. Meanwhile, 65 lipids were significantly changed, including 16 glycerophospholipids and 33 fatty acids, suggesting lipids might be another main energy supplier in the hepatopancreas. In the ovary, 7 carbohydrate and 1 lipid metabolic pathways were obviously affected, and 12 carbohydrates and 23 lipids were also significantly changed postmolt. Differently from the changes in the hepatopancreas, the glucose level was significantly decreased in the ovary, whereas the levels of eight glycerophospholipids and four unsaturated fatty acids were increased in the ovary but decreased in the hepatopancreas, suggesting lipids might be major energy reserves for ovarian development, and they were possibly exported from hepatopancreas. Moreover, the obvious changes in seven fatty acyl carnitines in the ovary indicate they were consumed via β-oxidation postmolt. Taken together, carbohydrates and fatty acyl carnitines were clearly the major energy reserves in pubertal molt. The hepatopancreas played a central role in the supply of energy reserves and nutrients. Numerous glycerophospholipids and unsaturated fatty acids may have accumulated in the ovary for the biosynthesis of egg yolk during ovarian development. This study suggests that proper increases in carbohydrate and lipid levels in crab feed ahead of pubertal molt may alleviate the effects of fasting and enhance successful reproduction.
•Metabolites were notably modulated in both hepatopancreas and ovary postmolt.•Carbohydrates were major energy reserves in hepatopancreas during pubertal molt.•Fatty acyl carnitines were major energy reserves in ovary during pubertal molt.•Glycerophospholipids and unsaturated fatty acids were gathered in ovary postmolt.
Lipoic acid (LA) has been an antioxidant with proven benefits in different species of productive interest. However, there is evidence of the effect of LA as a growth repressor and, consequently, of ...zootechnical performance. This study evaluated the effect of the co-administration of LA and short-chain fatty acid, sodium acetate (SA), as an additional source of energy on the utilization of yolk nutrients in Artemia sp. nauplii. A factorial experiment was designed with four levels of LA (0.0, 0.05, 0.5, and 5.0 μM) and four levels of SA (0.0, 2.0, 4.0, and 8.0 mM). Over 24 h, with sampling every 6 h, the total ammoniacal nitrogen (TAN) concentration in water, the concentration of protein, triglycerides, glucose, and the antioxidant capacity (ACAP) was evaluated in the artemia. The electron transporter system (ETS) activity and production of reactive oxygen species (ROS) in vivo were also recorded. Both LA and SA decreased TAN production. At 18 h, LA caused significant decreases in glucose content at the concentrations of 0.5 and 5.0 μM. On the other hand, SA preserved protein values in a dose-dependent manner at 12 h. Regarding ACAP, the LA showed ambivalent effects on this parameter, promoting a higher ACAP at 6 h; however, it promoted a more pro-oxidant state in the metanauplii at 24 h. While the ETS activity increased at 6 h, as an effect of the SA and LA administered separately, the co-administration of LA and SA revealed a possible antagonism that caused a decrease in the ETS activity by the action of LA. As for ROS, a decrease in production rates was found with the administration of LA, which was more noticeable at LA concentrations within the 0 and 2 mM levels of SA from 18 h onwards. Finally, the final energy content showed a scenario of the preservation of the energy reserves of artemia nauplii with the addition of SA. As expected, the LA negatively affected the energy content of the animals; however, the treatment with the highest energy content was the one that received 0.05 μM LA and 8.0 mM SA, suggesting the possibility of using these compounds together in order to compensate the side-effects of LA.
•Lipoic acid and sodium acetate can modify Artemia sp. yolk nutrient use via energy metabolism modulation.•Lipoic acid can deplete nutrients in Artemia sp. nauplii dose-dependently, promoting glucose use for energy, potentially sparing protein.•Sodium acetate may preserve Artemia sp. nutrition, possibly as an energy substrate and yolk nutrient catabolism inhibitor.•Lipoic acid and sodium acetate co-administration can synergistically preserve protein and energy in Artemia sp. nauplii.
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