Molecular Adaptation Research Articles

Physiological and molecular adaptation response of soybean seedlings under osmotic stress

Physiological and molecular adaptation response of soybean seedlings under osmotic stress

Disrupted hypothalamic transcriptomics and proteomics in a mouse model of type 2 diabetes exposed to recurrent hypoglycaemia

Aims/hypothesisRepeated exposures to insulin-induced hypoglycaemia in people with diabetes progressively impairs the counterregulatory response (CRR) that restores normoglycaemia. This defect is characterised by reduced secretion of glucagon and other counterregulatory hormones. Evidence indicates that glucose-responsive neurons located in the hypothalamus orchestrate the CRR. Here, we aimed to identify the changes in hypothalamic gene and protein expression that underlie impaired CRR in a mouse model of defective CRR.MethodsHigh-fat-diet fed and low-dose streptozocin-treated C57BL/6N mice were exposed to one (acute hypoglycaemia [AH]) or multiple (recurrent hypoglycaemia [RH]) insulin-induced hypoglycaemic episodes and plasma glucagon levels were measured. Single-nuclei RNA-seq (snRNA-seq) data were obtained from the hypothalamus and cortex of mice exposed to AH and RH. Proteomic data were obtained from hypothalamic synaptosomal fractions.ResultsThe final insulin injection resulted in similar plasma glucose levels in the RH group and AH groups, but glucagon secretion was significantly lower in the RH group (AH: 94.5±9.2 ng/l [n=33]; RH: 59.0±4.8 ng/l [n=37]; p<0.001). Analysis of snRNA-seq data revealed similar proportions of hypothalamic cell subpopulations in the AH- and RH-exposed mice. Changes in transcriptional profiles were found in all cell types analysed. In neurons from RH-exposed mice, we observed a significant decrease in expression of Avp, Pmch and Pcsk1n, and the most overexpressed gene was Kcnq1ot1, as compared with AH-exposed mice. Gene ontology analysis of differentially expressed genes (DEGs) indicated a coordinated decrease in many oxidative phosphorylation genes and reduced expression of vacuolar H+- and Na+/K+-ATPases; these observations were in large part confirmed in the proteomic analysis of synaptosomal fractions. Compared with AH-exposed mice, oligodendrocytes from RH-exposed mice had major changes in gene expression that suggested reduced myelin formation. In astrocytes from RH-exposed mice, DEGs indicated reduced capacity for neurotransmitters scavenging in tripartite synapses as compared with astrocytes from AH-exposed mice. In addition, in neurons and astrocytes, multiple changes in gene expression suggested increased amyloid beta (Aβ) production and stability. The snRNA-seq analysis of the cortex showed that the adaptation to RH involved different biological processes from those seen in the hypothalamus.Conclusions/interpretationThe present study provides a model of defective counterregulation in a mouse model of type 2 diabetes. It shows that repeated hypoglycaemic episodes induce multiple defects affecting all hypothalamic cell types and their interactions, indicative of impaired neuronal network signalling and dysegulated hypoglycaemia sensing, and displaying features of neurodegenerative diseases. It also shows that repeated hypoglycaemia leads to specific molecular adaptation in the hypothalamus when compared with the cortex.Data availabilityThe transcriptomic dataset is available via the GEO (http://www.ncbi.nlm.nih.gov/geo/), using the accession no. GSE226277. The proteomic dataset is available via the ProteomeXchange data repository (http://www.proteomexchange.org), using the accession no. PXD040183.Graphical

Growing strong muscle for better performance and weight loss

Growing strong muscle for better performance and weight loss Physical activity and exercise have beneficial effects on overall fitness and health. However, exercise-induced increases in metabolism require specific molecular adaptation of the muscle cells. This project aims to understand the molecular processes in the muscle during the adaptation to cold, exercise and obesity, thereby defining novel mechanisms of protein homeostasis with regard to the gene switch Nfe2l1.

Chromosome-level genome assembly of the deep-sea snail Phymorhynchus buccinoides provides insights into the adaptation to the cold seep habitat

BackgroundThe deep-sea snail Phymorhynchus buccinoides belongs to the genus Phymorhynchus (Neogastropoda: Raphitomidae), and it is a dominant specie in the cold seep habitat. As the environment of the cold seep is characterized by darkness, hypoxia and high concentrations of toxic substances such as hydrogen sulfide (H2S), exploration of the diverse fauna living around cold seeps will help to uncover the adaptive mechanisms to this unique habitat. In the present study, a chromosome-level genome of P. buccinoides was constructed and a series of genomic and transcriptomic analyses were conducted to explore its molecular adaptation mechanisms to the cold seep environments.ResultsThe assembled genome size of the P. buccinoides was approximately 2.1 Gb, which is larger than most of the reported snail genomes, possibly due to the high proportion of repetitive elements. About 92.0% of the assembled base pairs of contigs were anchored to 34 pseudo‐chromosomes with a scaffold N50 size of 60.0 Mb. Compared with relative specie in the shallow water, the glutamate regulative and related genes were expanded in P. buccinoides, which contributes to the acclimation to hypoxia and coldness. Besides, the relatively high mRNA expression levels of the olfactory/chemosensory genes in osphradium indicate that P. buccinoides might have evolved a highly developed and sensitive olfactory organ for its orientation and predation. Moreover, the genome and transcriptome analyses demonstrate that P. buccinoides has evolved a sulfite-tolerance mechanism by performing H2S detoxification. Many genes involved in H2S detoxification were highly expressed in ctenidium and hepatopancreas, suggesting that these tissues might be critical for H2S detoxification and sulfite tolerance.ConclusionsIn summary, our report of this chromosome-level deep-sea snail genome provides a comprehensive genomic basis for the understanding of the adaptation strategy of P. buccinoides to the extreme environment at the deep-sea cold seeps.

Plant Responses of Maize to Two formae speciales of Sporisorium reilianum Support Recent Fungal Host Jump.

Host jumps are a major factor for the emergence of new fungal pathogens. In the evolution of smut fungi, a putative host jump occurred in Sporisorium reilianum that today exists in two host-adapted formae speciales, the sorghum-pathogenic S. reilianum f. sp. reilianum and maize-pathogenic S. reilianum f. sp. zeae. To understand the molecular host-specific adaptation to maize, we compared the transcriptomes of maize leaves colonized by both formae speciales. We found that both varieties induce many common defense response-associated genes, indicating that both are recognized by the plant as pathogens. S. reilianum f. sp. reilianum additionally induced genes involved in systemic acquired resistance. In contrast, only S. reilianum f. sp. zeae induced expression of chorismate mutases that function in reducing the level of precursors for generation of the defense compound salicylic acid (SA), as well as oxylipin biosynthesis enzymes necessary for generation of the SA antagonist jasmonic acid (JA). In accordance, we found reduced SA levels as well as elevated JA and JA-Ile levels in maize leaves inoculated with the maize-adapted variety. These findings support a model of the emergence of the maize-pathogenic variety from a sorghum-specific ancestor following a recent host jump.

Integrating Non-photochemical Quenching (NPQ) Measurements for Identifying Flood-Tolerant Soybean Genotypes in the Era of Climate Change

Climate change has negatively affected agriculture worldwide, including soybean production. Studies have shown that rising temperatures and extreme weather events like droughts and floods significantly reduce soybean yields. Developing flood-tolerant soybean genotypes is crucial for ensuring food security. Conventional breeding programs are limited by laborious and imprecise visual rating methods for flooding tolerance identification. High-throughput platforms for plant phenotyping using imaging techniques offer potential solutions, but they lack information on underlying physiological mechanisms. Non-photochemical quenching (NPQ) is a molecular adaptation in photosynthesis that dissipates excess light energy, protecting plants from damage. This study aimed to integrate NPQ measurements into high-throughput phenotyping procedures to identify flooding-tolerant soybean genotypes. The study evaluated 160 soybean genotypes for flooding tolerance, identifying those with higher grain yield potential. Subsequently, ten genotypes were selected for monitoring NPQ responses under flooded conditions. Results showed that genotypes with higher grain yields also exhibited superior NPQ performance, suggesting a positive correlation between flooding tolerance and energy dissipation capacity. Among these genotypes, 58I60 RSF IPRO, 64HO130 I2X and BRS 525 displayed superior potential and could be further exploited in breeding efforts, considering their grain yield capacity, plant leaf area, and photoprotective capacity under flooding conditions. These findings suggest that integrating NPQ measurements into high-throughput phenotyping platforms can aid in identifying flood-tolerant soybean genotypes for breeding programs, leading to more resilient crops in the face of climate change. Further field studies are warranted to validate these hypotheses and improve crop models for future climate scenarios.

Profiling the genes associated with osmoadaptation and their variation by seasonally in Tuz Lake

Hypersaline environments are one of the extreme habitats in the world. Microorganisms living in a hypersaline environment have developed various molecular adaptation strategies to overcome these extreme conditions. The study aims to investigate the genes associated with osmoadaptation seasonal variation in Tuz Lake by PICRUSt2. Dada2 pipelines were applied for filtering, dereplication, chimera identification, and merging paired-end reads to construct table.qza and rep_seqs.qza files. Therefore, the PICRUSt2 was applied to analyze the metabolic function of archaeal and bacterial diversity in Tuz Lake by using table.qza and rep_seqs.qza files. As a result of metabolic functions based on 16S rDNA amplicon data, the genes related to potassium accumulation played an important role in osmoregulation in Tuz Lake, where the archaea population was dominant. Furthermore, bacteriorhodopsin, halorhodopsin, and sensory rhodopsin functions were determined. The abundance of bacteriorhodopsin and halorhodopsin were increased in summer and spring, respectively.

Molecular interaction network of plant-herbivorous insects

The interactions between plants and herbivorous insects are complex and involve multiple factors, driving species formation and leading to the beginning of co-evolution and diversification of plant and insect molecules. Various molecular processes regulate the interactions between plants and herbivorous insects. Here, we discuss the molecular patterns of plant perception of herbivorous insect feeding through activation of early signaling components, crosstalk of plant defense network composed of multiple plant hormones, and various adaptive changes in insect responses to plant defenses. Both plant defenses and insect counter-defenses are molecular adaptation processes to each other. Molecular models of plant-herbivorous insect interactions can more intuitively help us to understand the co-evolutionary arms race between plants and herbivorous insects. These results will provide detailed evidence to elucidate and enrich the interaction network of plant-herbivorous insects.

Molecular adaptation and codon usage bias analysis of Heterodera glycines and Heterodera avenae in saffron (Crocus sativus) corms from Jammu and Kashmir

This study explores the prevalence, distribution, and codon usage bias of nematode species, primarily Heterodera glycines and Heterodera avenae, within saffron corms. Nematode analysis identified H. glycines and H. avenae as the predominant species. Geographical locations exhibited distinct cyst infestation levels, with H. avenae showing higher prevalence. The study reveals the preference of these nematodes for saffron corms, raising concerns for saffron production and suggesting the implementation of monitoring and management strategies. Additionally, the study analyzes the codon usage bias (CUB) of saffron and its associated nematode pathogens. Codon usage bias analysis revealed an AT bias in Crocus sativus and its pathogens. Codon Adaptation Index (CAI) values suggested pathogen adaptation to the host. Correlation analysis highlighted the interplay of nucleotide composition, mutational pressure, and natural selection in codon usage patterns. Amino acid frequency and codon context analyses provided insights into evolution and physiological functions. Furthermore, the study observed a mutual codon preference between the host and pathogens for certain amino acids, highlighting specific interactions at the molecular level. This study provides valuable information for understanding the molecular biology of plant-nematode interactions, and its findings can be useful for developing effective management strategies against these pests in saffron production and other crops such as crop rotation, use of resistant cultivars, and application of nematode-suppressive amendments.

Mutation and Selection Induce Correlations between Selection Coefficients and Mutation Rates.

AbstractThe joint distribution of selection coefficients and mutation rates is a key determinant of the genetic architecture of molecular adaptation. Three different distributions are of immediate interest: (1) the "nominal" distribution of possible changes, prior to mutation or selection; (2) the "de novo" distribution of realized mutations; and (3) the "fixed" distribution of selectively established mutations. Here, we formally characterize the relationships between these joint distributions under the strong-selection/weak-mutation (SSWM) regime. The de novo distribution is enriched relative to the nominal distribution for the highest rate mutations, and the fixed distribution is further enriched for the most highly beneficial mutations. Whereas mutation rates and selection coefficients are often assumed to be uncorrelated, we show that even with no correlation in the nominal distribution, the resulting de novo and fixed distributions can have correlations with any combination of signs. Nonetheless, we suggest that natural systems with a finite number of beneficial mutations will frequently have the kind of nominal distribution that induces negative correlations in the fixed distribution. We apply our mathematical framework, along with population simulations, to explore joint distributions of selection coefficients and mutation rates from deep mutational scanning and cancer informatics. Finally, we consider the evolutionary implications of these joint distributions together with two additional joint distributions relevant to parallelism and the rate of adaptation.

A Large-Scale Candidate-Gene Association Mapping for Drought Tolerance and Agronomic Traits in Sugarcane.

Dissection of the genetic loci controlling drought tolerance traits with a complex genetic inheritance is important for drought-tolerant sugarcane improvement. In this study, we conducted a large-scale candidate gene association study of 649 candidate genes in a sugarcane diversity panel to identify genetic variants underlying agronomic traits and drought tolerance indices evaluated in plant cane and ratoon cane under water-stressed (WS) and non-stressed (NS) environments. We identified 197 significant marker-trait associations (MTAs) in 141 candidate genes associated with 18 evaluated traits with the Bonferroni correction threshold (α = 0.05). Out of the total, 95 MTAs in 78 candidate genes and 62 MTAs in 58 candidate genes were detected under NS and WS conditions, respectively. Most MTAs were found only in specific water regimes and crop seasons. These MTAs explained 7.93-30.52% of phenotypic variation. Association mapping results revealed that 34, 59, and 104 MTAs involved physiological and molecular adaptation, phytohormone metabolism, and drought-inducible genes. They identified 19 pleiotropic genes associated with more than one trait and many genes related to drought tolerance indices. The genetic and genomic resources identified in this study will enable the combining of yield-related traits and sugar-related traits with agronomic value to optimize the yield of sugarcane cultivars grown under drought-stressed and non-stressed environments.

Diatom adhesive trail proteins acquired by horizontal gene transfer from bacteria serve as primers for marine biofilm formation.

Biofilm-forming benthic diatoms are key primary producers in coastal habitats, where they frequently dominate sunlit intertidal substrata. The development of gliding motility in raphid diatoms was a key molecular adaptation that contributed to their evolutionary success. However, the structure-function correlation between diatom adhesives utilized for gliding and their relationship to the extracellular matrix that constitutes the diatom biofilm is unknown. Here, we have used proteomics, immunolocalization, comparative genomics, phylogenetics and structural homology analysis to investigate the evolutionary history and function of diatom adhesive proteins. Our study identified eight proteins from the adhesive trails of Craspedostauros australis, of which four form a new protein family called Trailins that contain an enigmatic Choice-of-Anchor A (CAA) domain, which was acquired through horizontal gene transfer from bacteria. Notably, the CAA-domain shares a striking structural similarity with one of the most widespread domains found in ice-binding proteins (IPR021884). Our work offers new insights into the molecular basis for diatom biofilm formation, shedding light on the function and evolution of diatom adhesive proteins. This discovery suggests that there is a transition in the composition of biomolecules required for initial surface colonization and those utilized for 3D biofilm matrix formation.

Phylotranscriptomics supports numerous polyploidization events and phylogenetic relationships in Nicotiana.

Nicotiana L. (Solanaceae) is of great scientific and economic importance, and polyploidization has been pivotal in shaping this genus. Despite many previous studies on the Nicotiana phylogenetic relationship and hybridization, evidence from whole genome data is still lacking. In this study, we obtained 995 low-copy genes and plastid transcript fragments from the transcriptome datasets of 26 Nicotiana species, including all sections. We reconstructed the phylogenetic relationship and phylogenetic network of diploid species. The incongruence among gene trees showed that the formation of N. sylvestris involved incomplete lineage sorting. The nuclear-plastid discordance and nuclear introgression absence indicated that organelle capture from section Trigonophyllae was involved in forming section Petunioides. Furthermore, we analyzed the evolutionary origin of polyploid species and dated the time of hybridization events based on the analysis of PhyloNet, sequence similarity search, and phylogeny of subgenome approaches. Our results highly evidenced the hybrid origins of five polyploid sections, including sections Nicotiana, Repandae, Rusticae, Polydicliae, and Suaveolentes. Notably, we provide novel insights into the hybridization event of section Polydicliae and Suaveolentes. The section Polydicliae formed from a single hybridization event between maternal progenitor N. attenuata and paternal progenitor N. undulata; the N. sylvestris (paternal progenitor) and the N. glauca (maternal progenitor) were involved in the formation of section Suaveolentes. This study represents the first exploration of Nicotiana polyploidization events and phylogenetic relationships using the high-throughput RNA-seq approach. It will provide guidance for further studies in molecular systematics, population genetics, and ecological adaption studies in Nicotiana and other related species.

Population dynamics and molecular adaption of Tetranychus cinnabarinus to long term thermal stress.

Global warming is a general trend of current era. Temperature is one of the most important non-biological factors that affects the development, life cycle and distribution of arthropods, which are a major component of agriculture pests. This study focused on life table parameters and the molecular adaption of Tetranychus cinnabarinus under long-term thermal stress. The life tables of T. cinnabarinus were constructed at room temperature (26°C) and high temperature (34°C). Results showed that although life span of mites was shortened, the developmental periods of egg, larva, nymph were accelerated and the peak egg laying period came earlier under high temperature, which resulted in faster expansion of pest mite population. RNA-seq was used to reveal the thermal adaption mechanism according to differentially expressed genes. Combined with transcriptome data and qPCR verification, MAPK, CAT, HSP20, and HSP70 were found highly expressed at 34°C, which were associated with thermal adaption of T. cinnabarinus. RNAi analysis proved that expression of HSP20 was closely related to survival of mites under high temperature. These results indicated that long-term high temperature treatment was beneficial to the expansion of the T. cinnabarinus population. The genes involved in heat tolerance of T. cinnabarinus such as MAPK-HSP pathway provides ideas for subsequent control measures. This article is protected by copyright. All rights reserved.

Transcriptomics and metabolomics reveal the molecular and metabolic adaptation to heat stress in Manila clam Ruditapes philippinarum

Temperature is an important environmental factor affecting metabolism, growth and life activities of marine bivalves. To reveal the molecular and metabolic responses to heat stress, comparative transcriptomics and metabolomics were performed in the commercially important bivalve, Manila clam Ruditapes philippinarum. Comparative transcriptomics revealed a total of 3980 differential genes (DEGs) mainly involved in energy metabolism, protein processing, glycerolphospholipid metabolism, inoxidizability and anti-apoptosis. Comparative metabolomic analysis identified 293 differential metabolites (DEMs) in the heat-stressed clams, including Acetyl-CoA, Beta-D-Glucose, phosphatidylcholine and free amino acids. For the heat-stress clams, they showed the significantly increased enzyme activities of AKP and ACP, as well as antioxidant-related enzyme activities (SOD and CAT) and oxidative damage substance (MDA). The changes in gene expression of glycolysis-related genes (GLUT1, GLK, HK1 and GPI6) and metabolites (Beta-D-Glucose and Acetyl-CoA) reflect the adjusted energy metabolism in the heat-stressed clams. The protein processing in endoplasmic reticulum may play the important roles in the stability of cell membrane structure during heat adaptation. The increased contents of glycerophospholipid (PC) may be essential to maintain the stability and permeability of cell membrane in the heat-stressed clams. Molecular chaperones (HSP70 and HSP90) may participate in the degradation of misfolded proteins to maintain cell homeostasis during the heat stress. To defense the heat stress, clams also initiate the protection and defense mechanisms by activating antioxidant system, innate immune system and anti-apoptotic system. These findings will shed new lights on molecular and metabolic adaptation to heat stress in the intertidal mollusks in a warming climate at the global scale.

An Insight into Occurrence, Biology, and Pathogenesis of Rice Root-Knot Nematode Meloidogyne graminicola.

Rice (Oryza sativa L.) is one of the most widely grown crops in the world, and is a staple food for more than half of the global total population. Root-knot nematodes (RKNs), Meloidogyne spp., and especially M. graminicola, seem to be significant rice pests, which makes them the most economically important plant-parasitic nematode in this crop. RKNs develop a feeding site in galls by causing host cells to differentiate into hypertrophied, multinucleate, metabolically active cells known as giant cells. This grazing framework gives the nematode a constant food source, permitting it to develop into a fecund female and complete its life cycle inside the host root. M. graminicola effector proteins involved in nematode parasitism, including pioneer genes, were functionally characterized in earlier studies. Molecular modelling and docking studies were performed on Meloidogyne graminicola protein targets, such as β-1,4-endoglucanase, pectate lyase, phospholipase B-like protein, and G protein-coupled receptor kinase, to understand the binding affinity of Beta-D-Galacturonic Acid, 2,6,10,15,19,23-hexamethyltetracosane, (2S)-2-amino-3-phenylpropanoic acid, and 4-O-Beta-D-Galactopyranosyl-Alpha-D-Glucopyranose against ligand molecules of rice. This study discovered important molecular aspects of plant-nematode interaction and candidate effector proteins that were regulated by M. graminicola-infected rice plants. To the best of our knowledge, this is the first study to describe M. graminicola's molecular adaptation to host parasitism.

Integrating Transcriptional, Metabolic, and Physiological Responses to Drought Stress in Ilex paraguariensis Roots.

The appearance of water stress episodes triggers leaf abscission and decreases Ilex paraguariensis yield. To explore the mechanisms that allow it to overcome dehydration, we investigated how the root gene expression varied between water-stressed and non-stressed plants and how the modulation of gene expression was linked to metabolite composition and physiological status. After water deprivation, 5160 differentially expressed transcripts were obtained through RNA-seq. The functional enrichment of induced transcripts revealed significant transcriptional remodelling of stress-related perception, signalling, transcription, and metabolism. Simultaneously, the induction of the enzyme 9-cis-expoxycarotenoid dioxygenase (NCED) transcripts reflected the central role of the hormone abscisic acid in this response. Consequently, the total content of amino acids and soluble sugars increased, and that of starch decreased. Likewise, osmotic adjustment and radical growth were significantly promoted to preserve cell membranes and water uptake. This study provides a valuable resource for future research to understand the molecular adaptation of I. paraguariensis plants under drought conditions and facilitates the exploration of drought-tolerant candidate genes.

Involvement of insulin-like growth factor binding proteins (IGFBPs) and activation of insulin/IGF-like signaling (IIS)-target of rapamycin (TOR) signaling cascade in pacific white shrimp, Litopenaeus vannamei exposed to acute low-salinity

Acute low-salinity induces multiple stress responses and significantly impact the health of aquatic animals. However, the molecular regulation network and metabolic adaptation of low salinity stress in aquatic organisms remain unclear. The insulin-like growth factor binding proteins (IGFBPs) and insulin/IGF-like signaling (IIS)-target of rapamycin (TOR) signaling cascade are evolutionarily conserved regulators known to play crucial roles in response to various stressors. In this study, we used the euryhaline Pacific white shrimp (Litopenaeus vannamei) as a model organism to investigate the involvement of IGFBP and IIS-TOR signaling cascade in acute low-salinity response. We found seven LvIGFBPs and evaluated 18s as one of most stable internal reference genes under acute low salinity stress. The expression of LvIGFBP4, LvSIBD1, and LvSIBD2 was significantly increased after 6-hours 5‰ salinity treatment. LvSIBD2 was specifically expressed on the surface of gill branch axis. Acute low-salinity significantly induced the phosphorylation of Akt and S6K in the gill but not in the muscle. We found acute low-salinity increased the levels of total essential amino acids, including leucine and arginine, while decreasing the total non-essential amino acid levels in the gill. Furthermore, glucose and key metabolites in glycolysis and tricarboxylic acid cycle (TCA cycle) were increased, indicating remodeling of energy metabolism occurred. These results demonstrate the involvement of IGFBP and IIS-TOR signaling cascade in acute low-salinity response and provide new insights into understanding the mechanism of osmoregulation in euryhaline crustacean species.

High copper promotes cell wall remodeling and oxidative stress in Histoplasma capsulatum, as revealed by proteomics

Histoplasma experiences nutritional stress during infection as a result of immune cells manipulating essential nutrients, such as metal ions, carbon, nitrogen, and vitamins. Copper (Cu) is an essential metallic micronutrient for living organisms; however, it is toxic in excess. Microbial pathogens must resist copper toxicity to survive. In the case of Histoplasma, virulence is supported by high-affinity copper uptake during late infection, and copper detoxification machinery during early macrophage infection. The objective of this study was to characterize the global molecular adaptation of Histoplasma capsulatum to copper excess using proteomics. Proteomic data revealed that carbohydrate breakdown was repressed, while the lipid degradation pathways were induced. Surprisingly, the production of fatty acids/lipids was also observed, which is likely a result of Cu-mediated damage to lipids. Additionally, the data showed that the fungus increased the exposition of glycan and chitin on the cell surface in high copper. Yeast upregulated antioxidant enzymes to counteract ROS accumulation. The induction of amino acid degradation, fatty acid oxidation, citric acid cycle, and oxidative phosphorylation suggest an increase in aerobic respiration for energy generation. Thus, H. capsulatum's adaptive response to high Cu is putatively composed of metabolic changes to support lipid and cell wall remodeling and fight oxidative stress.

Ocean acidification increases copper accumulation and exacerbates copper toxicity in Amphioctopus fangsiao (Mollusca: Cephalopoda): A potential threat to seafood safety

Ocean acidification (OA) and trace metal pollutants coexist to exert combined effects on the functions and services of marine ecosystems. Increasing atmospheric carbon dioxide has caused a decrease in the pH of the ocean, affecting the bioavailability and speciation of trace metals and consequently altering metal toxicity in marine organisms. As an important trace metal functioned in hemocyanin, the richness of Copper (Cu) in octopuses is remarkable. Therefore, the biomagnification and bioaccumulation capacities of Cu in octopuses may be a non-negligible risk of contamination. Here, Amphioctopus fangsiao was continuously exposed to acidified seawater (pH 7.8) and copper (50 μg/L) to investigate the combined effect of ocean acidification and Cu exposure on marine mollusks. Our results showed that A. fangsiao could adapt well to ocean acidification after 21 days of the rearing experiment. However, the accumulation of Cu in A. fangsiao intestine increased significantly in acidified seawater under high levels of Cu stress. In addition, Cu exposure can influence the physiological function of A. fangsiao, including growth and feeding. This study also demonstrated that Cu exposure disturbed glucolipid metabolism and induced oxidative damage to intestine tissue, and ocean acidification further exacerbated these toxic effects. The obvious histological damage and microbiota alterations were also caused by Cu stress and its combined effect with ocean acidification. At the transcription level, we found numerous differentially expressed genes (DEGs) and significantly enriched KEGG pathways, involving glycolipid metabolism, transmembrane transport, glucolipid metabolism, oxidative stress, mitochondrial, protein and DNA damage, all revealing the strong toxicological synergetic effect of Cu and OA exposure and the molecular adaptation mechanism of A. fangsiao. Collectively, this study demonstrated that octopuses may withstand future ocean acidification conditions, however, the complex interactions of future OA and trace metal pollution need to be emphasized. OA can influence the toxicity of trace metals, inducing a potential threat to marine organism safety.