Combined effects of salinity, temperature and hypoxia on Daphnia magna metabolism

Chemometrics combined with comprehensive two-dimensional gas chromatography-mass spectrometry for the identification of Baijiu vintage

The identification of baijiu vintage is crucial for quality assessment and economic value determination. However, its complex composition and multifaceted influences pose significant technical challenges, necessitating research into its aging mechanisms and the development of related identification methods. This study utilized Chemometrics in conjunction with GC × GC-TOFMS for Baijiu Vintage identification. Data compression achieved a reduction of over 1000-fold without compromising key information, enabling analysis on many samples and get their changing regular in a big matrix by MCR. Subsequently, MCR-ALS facilitated the extraction of physical and chemical meaningful information related to baijiu vintage. Key MCR principal components suitable for qualitative and quantitative assessments were selected using CARS-PLS. The regression model demonstrated errors of less than one year. Furthermore, a PLS-DA model provided 30 MCR principal components as potential markers. The research results provide technical support for baijiu vintage identification and lay the groundwork for studying the changing patterns of flavor compounds in baijiu.

Environmental metabolomics uncovers oxidative stress, amino acid dysregulation, and energy impairment in Daphnia magna with exposure to industrial effluents

Anthropogenic activities are regarded as point sources of pollution entering freshwater bodies worldwide. With over 350,000 chemicals used in manufacturing, wastewater treatment and industrial effluents are comprised of complex mixtures of organic and inorganic pollutants of known and unknown origins. Consequently, their combined toxicity and mode of action are not well understood in aquatic organisms such as Daphnia magna. In this study, effluent samples from wastewater treatment and industrial sectors were used to examine molecular-level perturbations to the polar metabolic profile of D. magna. To determine if the industrial sector and/or the effluent chemistries played a role in the observed biochemical responses, Daphnia were acutely (48 h) exposed to undiluted (100%) and diluted (10, 25, and 50%) effluent samples. Endogenous metabolites were extracted from single daphnids and analyzed using targeted mass spectrometry-based metabolomics. The metabolic profile of Daphnia exposed to effluent samples resulted in significant separation compared to the unexposed controls. Linear regression analysis determined that no single pollutant detected in the effluents was significantly correlated with the responses of metabolites. Significant perturbations were uncovered across many classes of metabolites (amino acids, nucleosides, nucleotides, polyamines, and their derivatives) which serve as intermediates in keystone biochemical processes. The combined metabolic responses are consistent with oxidative stress, disruptions to energy metabolism, and protein dysregulation which were identified through biochemical pathway analysis. These results provide insight into the molecular processes driving stress responses in D. magna. Overall, we determined that the metabolic profile of Daphnia could not be predicted by the chemical composition of environmentally relevant mixtures. The findings of this study demonstrate the advantage of metabolomics in conjunction with chemical analyses to assess the interactions of industrial effluents. This work further demonstrates the ability of environmental metabolomics to characterize molecular-level perturbations in aquatic organisms exposed to complex chemical mixtures directly.

Metabolism response mechanism in the gill of Oreochromis mossambicus under salinity, alkalinity and saline-alkalinity stresses

Saline-alkalinity is one of the important ecological parameter that has an impact function on the physiological metabolism, osmoregulation, survival, growth, development and distribution of teleost fish. Oreochromis mossambicus, a species of euryhaline that can withstand a wide variety of salinities, may be used as a research model animal in environmental studies. In order to detect the metabolism responses and mechanisms of different osmotic stresses tolerance in the gills of O. mossambicus, in present study, the metabolic responses of O. mossambicus subjected to salinity (25 g/L, S_S), alkalinity (4 g/L, A_S) and saline-alkalinity stress (salinity: 25 g/L, alkalinity: 4 g/L; SA_S) with the control environment (freshwater, C_S) were investigated by LC-MS/MS-based metabolomics. The metabolism results indicated that numerous metabolites were identified between the stress groups and the control group. In addition, under three osmotic stresses, the amino acid and carbohydrate metabolism, levels of amino acids, osmolytes and energy substances, such as L-lysine, arachidonic acid, docosahexaenoic acids, creatine and taurine, were significantly affected and changed in the metabolism of the gills of O. mossambicus. The metabolism data indicated that signal transduction and regulation pathways, including FoxO signaling pathway, mTOR signaling pathway and prolactin signaling pathway, were enriched in the gill during adaptation to high salinity, alkalinity and saline-alkalinity stress. The results of this study provide more comprehensive and reliable data for the osmotic pressure regulation mechanism and biological response of euryhaline teleost, and provide reliable scientific basis for the breeding and research of high salinity tolerance population, and further promote the development and utilization of saline-alkalinity water resources.

Effects of temperature and combinational exposures on lipid metabolism in aquatic invertebrates

Studies of changes in fatty acids in response to environmental temperature changes have been conducted in many species, particularly mammals. However, few studies have considered aquatic invertebrates, even though they are particularly vulnerable to changes in environmental temperature. In this review, we summarize the process by which animals synthesize common fatty acids and point out differences between the fatty acid profiles of vertebrates and those of aquatic invertebrates. Unlike vertebrates, some aquatic invertebrates can directly synthesize polyunsaturated fatty acids (PUFAs), which can be used to respond to temperature changes. Various studies have shown that aquatic invertebrates increase the degree of saturation in their fatty acids through an increase in saturated fatty acid production or a decrease in PUFAs as the temperature increases. In addition, we summarize recent studies that have examined the complex effects of temperature and combinational stressors to determine whether the degree of saturation in aquatic invertebrates is influenced by other factors. The combined effects of carbon dioxide partial pressure, food quality, starvation, salinity, and chemical exposures have been confirmed, and fatty acid profile changes in response to high temperature were greater than those from combinational stressors.

The interplay between prior selection, mild intermittent exposure, and acute severe exposure in phenotypic and transcriptional response to hypoxia

Hypoxia has profound and diverse effects on aerobic organisms, disrupting oxidative phosphorylation and activating several protective pathways. Predictions have been made that exposure to mild intermittent hypoxia may be protective against more severe exposure and may extend lifespan. Here we report the lifespan effects of chronic, mild, intermittent hypoxia, and short‐term survival in acute severe hypoxia in four clones of Daphnia magna originating from either permanent or intermittent habitats. We test the hypothesis that acclimation to chronic mild intermittent hypoxia can extend lifespan through activation of antioxidant and stress‐tolerance pathways and increase survival in acute severe hypoxia through activation of oxygen transport and storage proteins and adjustment to carbohydrate metabolism. Unexpectedly, we show that chronic hypoxia extended the lifespan in the two clones originating from intermittent habitats but had the opposite effect in the two clones from permanent habitats, which also showed lower tolerance to acute hypoxia. Exposure to chronic hypoxia did not protect against acute hypoxia; to the contrary, Daphnia from the chronic hypoxia treatment had lower acute hypoxia tolerance than normoxic controls. Few transcripts changed their abundance in response to the chronic hypoxia treatment in any of the clones. After 12 h of acute hypoxia treatment, the transcriptional response was more pronounced, with numerous protein‐coding genes with functionality in oxygen transport, mitochondrial and respiratory metabolism, and gluconeogenesis, showing upregulation. While clones from intermittent habitats showed somewhat stronger differential expression in response to acute hypoxia than those from permanent habitats, contrary to predictions, there were no significant hypoxia‐by‐habitat of origin or chronic‐by‐acute treatment interactions. GO enrichment analysis revealed a possible hypoxia tolerance role by accelerating the molting cycle and regulating neuron survival through upregulation of cuticular proteins and neurotrophins, respectively.

Environmental Metabolomics Promises and Achievements in the Field of Aquatic Ecotoxicology: Viewed through the Pharmaceutical Lens

Scientists often set ambitious targets using environmental metabolomics to address challenging ecotoxicological issues. This promising approach has a high potential to elucidate the mechanisms of action (MeOAs) of contaminants (in hazard assessments) and to develop biomarkers (in environmental biomonitoring). However, metabolomics fingerprints often involve a complex mixture of molecular effects that are hard to link to a specific MeOA (if detected in the analytical conditions used). Given these promises and limitations, here we propose an updated review on the achievements of this approach. Metabolomics-based studies conducted on the effects of pharmaceutical active compounds in aquatic organisms provide a relevant means to review the achievements of this approach, as prior knowledge about the MeOA of these molecules could help overcome some shortcomings. This review highlighted that current metabolomics advances have enabled more accurate MeOA assessment, especially when combined with other omics approaches. The combination of metabolomics with other measured biological endpoints has also turned out to be an efficient way to link molecular effects to (sub)-individual adverse outcomes, thereby paving the way to the construction of adverse outcome pathways (AOPs). Here, we also discuss the importance of determining MeOA as a key strategy in the identification of MeOA-specific biomarkers for biomonitoring. We have put forward some recommendations to take full advantage of environmental metabolomics and thus help fulfil these promises.

Pesticide-induced metabolic changes are amplified by food stress

In natural ecosystems, long-term detrimental effects of pesticides may occur at very low concentrations, below those considered safe by the governmental risk assessment. Mechanisms potentially responsible for this unexpected sensitivity include environmental stress-factors such as food deficiency. To understand this so called "effect-paradox", we investigated how food stress interacts with insecticide-induced biochemical fingerprints. Therefore, we measured metabolomic perturbations in Daphnia magna following a 24 h exposure to esfenvalerate under high and low food conditions. In total, 160 metabolites covering the groups of amino acids, fatty acids, lipids, and sugars were analyzed. At 0.001 μg/L esfenvalerate - a factor of >200 below the acute lethal concentration (LC₅₀) - the endogenous metabolome was significantly affected. Further, the effect under low food conditions was considerably stronger compared to high food conditions. Individual metabolites showed up to 7-fold stronger effects under low food conditions. In general, the metabolomic changes were largely dose-specific and increased over seven days after contamination. We conclude that the metabolic profiles are altered for at least seven days after a pulse exposure, and therefore might be a key process to understanding population level changes at ultra-low pesticide concentrations in the field.

The potential environmental risks of the utilization of composts from household food waste

Modern technologies (especially with the help of autonomous measurement and control systems) introduced automatic composters for the disposal of household food waste production. Environmental risks connected with the utilization of these composts can be characterized by the high electrical conductivity caused by a presence of sodium chloride in food. Electrical conductivity influences the ecotoxicity of the composts. The presence of pesticides in composted food also represents an important environmental problem. The following pesticides were found in compost samples from household food waste: 1,3,5-triazine, methyl trithion, bifenthrin, bifenox, carbophenothion, pirimicarb, dioxacarb, desmetryn. Pesticide content in composts varied from 0.3 to 16.3 μg/kg, the average value being 30.4 ± 10.1 μg/kg dry matter. The higher decomposition was found of "modern" pesticides in the composters. The removal of salts can ensure that inhibition will be < 30% while washing with the ratio of 1:3 will result in the inhibition < 5%. However, this way of processing is not effective for other organisms-Poecilia reticulata (mortality 100%) and Daphnia magna (immobilisation 100%) using this procedure as well as washing of the compost in the ratio 3:1.

Resurrecting the metabolome: Rapid evolution magnifies the metabolomic plasticity to predation in a natural Daphnia population

Populations rely on already present plastic responses (ancestral plasticity) and evolution (including both evolution of mean trait values, constitutive evolution, and evolution of plasticity) to adapt to novel environmental conditions. Because of the lack of evidence from natural populations, controversy remains regarding the interplay between ancestral plasticity and rapid evolution in driving responses to new stressors. We addressed this topic at the level of the metabolome utilizing a resurrected natural population of the water flea Daphnia magna that underwent a human-caused increase followed by a reduction in predation pressure within ~16 years. Predation risk induced plastic changes in the metabolome which were mainly related to shifts in amino acid and sugar metabolism, suggesting predation risk affected protein and sugar utilization to increase energy supply. Both the constitutive and plastic components of the metabolic profiles showed rapid, probably adaptive evolution whereby ancestral plasticity and evolution contributed nearly equally to the total changes of the metabolomes. The subpopulation that experienced the strongest fish predation pressure and showed the strongest phenotypic response, also showed the strongest metabolomic response to fish kairomones, both in terms of the number of responsive metabolites and in the amplitude of the multivariate metabolomic reaction norm. More importantly, the metabolites with higher ancestral plasticity showed stronger evolution of plasticity when predation pressure increased, while this pattern reversed when predation pressure relaxed. Our results therefore highlight that the evolution in response to a novel pressure in a natural population magnified the metabolomic plasticity to this stressor.

Ecological and toxicological assessments of anthropogenic contaminants based on environmental metabolomics

There has long been a great concern with growing anthropogenic contaminants and their ecological and toxicological effects on living organisms and the surrounding environment for decades. Metabolomics, a functional readout of cellular activity, can capture organismal responses to various contaminant-related stressors, acquiring direct signatures to illustrate the environmental behaviours of anthropogenic contaminants better. This review entails the application of metabolomics to profile metabolic responses of environmental organisms, e.g. animals (rodents, fish, crustacean and earthworms) and microorganisms (bacteria, yeast and microalgae) to different anthropogenic contaminants, including heavy metals, nanomaterials, pesticides, pharmaceutical and personal products, persistent organic pollutants, and assesses their ecotoxicological impacts with regard to literature published in the recent five years. Contaminant-induced metabolism alteration and up/down-regulation of metabolic pathways are revealed in typical organisms. The obtained insights of variations in global metabolism provide a distinct understanding of how anthropogenic contaminants exert influences on specific metabolic pathways on living organisms. Thus with a novel ecotechnique of environmental metabolomics, risk assessments of anthropogenic contaminants are profoundly demonstrated.

The main effects of elevated CO2 and soil-water deficiency on 1H NMR-based metabolic fingerprints of Coffea arabica beans by factorial and mixture design

The metabolic response of Coffea arabica trees in the face of the rising atmospheric concentration of carbon dioxide (CO₂) combined with the reduction in soil-water availability is complex due to the various (bio)chemical feedbacks. Modern analytical tools and the experimental advance of agronomic science tend to advance in the understanding of the metabolic complexity of plants. In this work, Coffea arabica trees were grown in a Free-Air Carbon Dioxide Enrichment dispositive under factorial design (2²) conditions considering two CO₂ levels and two soil-water availabilities. The ¹H NMR mixture design-fingerprinting effects of CO₂ and soil-water levels on beans were strategically investigated using the principal component analysis (PCA), analysis of variance (ANOVA) - simultaneous component analysis (ASCA) and partial least squares-discriminant analysis (PLS-DA). From the ASCA, the CO₂ factor had a significant effect on changing the ¹H NMR profile of fingerprints. The soil-water factor and interaction (CO₂ × soil-water) were not significant. ¹H NMR fingerprints with PCA, ASCA and PLS-DA analysis determined spectral profiles for fatty acids, caffeine, trigonelline and glucose increases in beans from current CO₂, while quinic acid/chlorogenic acids, malic acid and kahweol/cafestol increased in coffee beans from elevated CO₂. PLS-DA results revealed a good classification performance between the significant effect of the atmospheric CO₂ levels on the fingerprints, regardless of the soil-water availabilities. Finally, the PLS-DA model showed good prediction ability, successfully classifying validation data-set of coffee beans collected over the vertical profile of the plants and included several fingerprints of different extracting solvents. The results of this investigation suggest that the association of experimental design, mixture design, PCA, ASCA and PLS-DA can provide accurate information on a series of metabolic changes provoked by climate changes in products of commercial importance, in addition to minimizing the extra work necessary in classic analytical approaches, encouraging the development of similar strategies.

Critical knowledge gaps and relevant variables requiring consideration when performing aquatic ecotoxicity assays

The increasing diversity and complexity of contaminants released in the environment continuously lead to new challenges when applying ecotoxicity assays. This paper comprises a review concerning exposure assessment and highlights important variables that should be taken into account when investigating aquatic media toxicity under both laboratory or field conditions. Thus, to reflect as much as possible what occurs in nature, ecotoxicity assays must carefully consider these variables in their experimental design. This includes contaminant properties, the selected bioindicators and biomarkers, the dose mode/regime, concentration vs. load, exposure to single vs. multiple contaminants and exposure of single vs. multiple species. Many of these, however, are not usually taken into account, leading to critical knowledge gaps in this area, discussed in detail herein.

Interaction of clopidogrel and fufang danshen dripping pills assay in coronary heart disease based on non-target metabolomics

ETHNOPHARMACOLOGICAL RELEVANCE

Clopidogrel is the recommended treatment by current clinical practice guidelines to prevent adverse cardiovascular events in patients with coronary heart disease (CHD), but this treatment regimen still fails and 5-40% patients display inadequate antiplatelet responses. Fufang Danshen Dripping Pill (FDDP), a Chinese patient drug, was used as the combination with clopidogrel to improve the therapeutic effect. However, the mechanism of the interaction between clopidogrel and FDDP has not been elucidated.

MATERIALS AND METHODS

We have used non-targeted metabolism method based on GC-MS and LC-MS for the investigation of drug interactions between clopidogrel and FDDP. 63 patients were divided into four groups with different dosage regimen and the serum samples were collected for the analysis.

RESULTS

We have found 5 and 55 differential metabolites between health volunteer group and CHD patients group, respectively. The contents of these differential metabolites had diverse changes in clopidogrel group, FDDP group, and drug combination group, indicating that the clopidogrel and FDDP combination can adjust the glycometabolism, lipid metabolism, and phospholipid metabolism, sequentially made the content of downstream related metabolites towards to the health volunteer group.

CONCLUSION

This work has explained the mechanism of the interaction between clopidogrel and FDDP from the point of view of metabolic product change, and revealed the potential metabolic pathways it affects, which provided the new ideas for clinical medication.

Functional responses of Daphnia magna to zero-mean flow turbulence

Daphnia are important to understanding the biogeochemistry of aquatic ecosystems, mainly because of their ability to filter bacteria, algae and inorganic particles as well. Although there are many studies on the general effects that biotic and abiotic stressors, increased temperature and hypoxia, salinity, metals, pharmaceuticals, pesticides, etc., have on Daphnia populations, little is known about the impact elevated turbulence has. Here, we show that turbulence affects Daphnia magna survival, swimming behaviour and filtering capacity. Our data demonstrate that altering their habitat by induced mixing from turbulence, induces an increased filtering capacity of the Daphnia magna individuals, provided the level of background turbulence (defined by the dissipation of turbulent kinetic energy) is lower than ε = 0.04 cm² s⁻³. The filtering capacity reduced exponentially with increasing ε, and at ε > 1 cm² s⁻³ both mobility and filtration were suppressed and eventually led to the death of all the Daphnia magna individuals.

Metabolic responses in the gills of tongue sole (Cynoglossus semilaevis) exposed to salinity stress using NMR-based metabolomics

Salinity is an important environmental factor affecting fish physiology. Tongue sole (Cynoglossus semilaevis) is a euryhaline species that can survive in a wide range of salinity, and might be used as a promising model animal for environmental science. In this study, by using the nuclear magnetic resonance (¹H NMR)-based metabolomics, amino acids analysis and real-time quantitative PCR assay, we investigated the metabolic responses in the gills and plasma of tongue sole subjected to hypo- (0 ppt, S0) and hyper-osmotic stress (50 ppt, S50) from isosmotic environment (30 ppt, S30). The results showed that the metabolic profiles of S50 were significantly different from those of S0 and S30 groups, and a clear overlap was found between the latter two groups. Ten metabolites were significantly different between the salt stress groups and the isosmotic group. Taurine and creatine elevated in both S0 and S50 groups. Choline decreased in S50 group while increased in S0 group. Amino acids and energy compounds were higher in the gills of S50 group. The metabolic network showed that ten metabolic pathways were all found in S50 group, while seven pathways were observed in S0 group. Meanwhile, the transcript levels of the Tau-T and ATP synthase in the gills increased with increasing salinity. Aspartate and methionine exhibited significant differences in the plasma among the groups, but did not show differences in the gills. Comparatively, glutamate exhibited significant differences both in the plasma and the gills. Overall, these findings provide a preliminary profile of osmotic regulation in euryhaline fish.

Effects of salinity changes on aquatic organisms in a multiple stressor context

Under global change, the ion concentration of aquatic ecosystems is changing worldwide. Many freshwater ecosystems are being salinized by anthropogenic salt inputs, whereas many naturally saline ones are being diluted by agricultural drainages. This occurs concomitantly with changes in other stressors, which can result in additive, antagonistic or synergistic effects on organisms. We reviewed experimental studies that manipulated salinity and other abiotic stressors, on inland and transitional aquatic habitats, to (i) synthesize their main effects on organisms' performance, (ii) quantify the frequency of joint effect types across studies and (iii) determine the overall individual and joint effects and their variation among salinity-stressor pairs and organism groups using meta-analyses. Additive effects were slightly more frequent (54%) than non-additive ones (46%) across all the studies (n = 105 responses). However, antagonistic effects were dominant for the stressor pair salinity and toxicants (44%, n = 43), transitional habitats (48%, n = 31) and vertebrates (71%, n = 21). Meta-analyses showed detrimental additive joint effects of salinity and other stressors on organism performance and a greater individual impact of salinity than the other stressors. These results were consistent across stressor pairs and organism types. These findings suggest that strategies to mitigate multiple stressor impacts on aquatic ecosystems should prioritize restoring natural salinity concentrations.This article is part of the theme issue 'Salt in freshwaters: causes, ecological consequences and future prospects'.

Culture conditions and nutrition requirements for the mycelial growth of Isaria farinosa (Hypocreales: Cordycipitaceae) and the altitude effect on its growth and metabolome

Isaria farinosa is a pathogen of alpine Thitarodes larvae that are hosts for the Chinese medicinal fungus, Ophiocordyceps sinensis. A matrix analysis indicated that the optimal culture conditions for the mycelial growth of I. farinosa are a 50-mL liquid broth in a 250-mL flask at more than 100-rpm rotation and 15–25 °C. Illumination does not affect the mycelial growth. The optimal nutrition requirements are D-(+)-galactose and D-(−)-fructose as carbon resources and D-cysteine as well as yeast powder, peptone, and beef extract as nitrogen resources at a carbon-to-nitrogen ratio of 1:1 to 1:7. The mineral component and vitamins also significantly increase the mycelial growth of I. farinosa. Based on the optimal culture conditions and nutrition requirements for the mycelial growth of I. farinosa, the effects of altitude on mycelial growth and its metabolome were evaluated using quadrupole-time-of-flight/mass spectrometry, principal component analysis and partial least squares discriminant analysis. The altitude did not affect the mycelial production but significantly regulated its metabolome. The study presents a new approach to better select a method for producing more useful metabolites and highlights the necessity of establishing standards for culturing methods related to altitude to preserve fungal quality; additionally, the results indicate that the use of a fermenter may meet the demands of large-scale mycelial production.

Daphnia magna filtration efficiency and mobility in laminar to turbulent flows

Daphnia are filter feeder organisms that prey on small particles suspended in the water column. Since Daphnia individuals can feed on wastewater particles, they have been recently proposed as potential organisms for tertiary wastewater treatment. However, analysing the effects of hydrodynamics on Daphnia individuals has scarcely been studied. This study focuses then, on quantifying the filtration and swimming velocities of D. magna individuals under different hydrodynamic conditions. Both D. magna filtration and movement responded differently if the flow was laminar or if it was turbulent. In a laminar-dominated flow regime Daphnia filtration was enhanced up to 2.6 times that of a steady flow, but in the turbulent-dominated flow regime D. magna filtration was inhibited. In the laminar flow regime D. magna individuals moved freely in all directions, whereas in the turbulent flow regime they were driven by the streamlines of the flow. A model based on Daphnia-particle encountering revealed that the filtration efficiency in the laminar regime was driven by the length of the D. magna individuals and the shear rate imposed by the system.