Antioxidants

Research

18 pages, 9829 KiB

Open AccessArticle

Effects of Methyl Farnesoate on the Growth and Antioxidant Capacity of Neocaridina denticulata

by Ying Chen, Xiaojuan Sun, Jiahao Du, Jingjie Hu, Zhenmin Bao and Zhe Qu

Antioxidants 2025, 14(6), 635; https://doi.org/10.3390/antiox14060635 - 25 May 2025

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Sesquiterpenoid hormones are widely present in arthropods and play crucial roles in growth, molting and reproduction. Methyl farnesoate (MF) functions similarly to juvenile hormone (JH) in crustaceans, playing a broad regulatory role in their growth and development. However, compared to insects, systematic studies [...] Read more.

Sesquiterpenoid hormones are widely present in arthropods and play crucial roles in growth, molting and reproduction. Methyl farnesoate (MF) functions similarly to juvenile hormone (JH) in crustaceans, playing a broad regulatory role in their growth and development. However, compared to insects, systematic studies on the mechanisms of sesquiterpenoid hormones in crustaceans are still lacking. Neocaridina denticulata, a small freshwater shrimp known for its fast growth, high reproductive capacity and ease of maintenance, is an ideal model organism for crustacean research. To investigate the effects of MF on the growth and development of juvenile N. denticulata, MF feeding experiments were conducted and the changes at the phenotypic and molecular levels were examined. In this experiment, the basal diet was used as a control, with 40 μg/kg, 4 μg/kg and 0.4 μg/kg of MF added to the feed. The MF-enriched diets were fed to juvenile N. denticulata and the growth in body length was measured every 10 days. After 40 days of feeding experiment, the activities of amylase (AMS), lipase (LPS), trypsin (Try), superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GSH-PX) were assessed, and transcriptome analysis was performed. We found that MF showed an initial inhibitory effect on body length (day 30), but by day 40, the low-concentration group exhibited significantly enhanced growth compared to the control, indicating a dose- and time-dependent effect. Activities of AMS, LPS, Try and SOD generally decreased, whereas MDA levels and GSH-PX activity increased after 40 days of MF exposure. Moreover, transcriptomic analysis revealed that MF regulated various biological processes including growth, metabolism and immune responses. High concentration group appeared to restrict growth via modulation of exoskeleton-related and cellular stress genes. Medium concentration group enhanced growth by optimizing metabolic and signaling pathways. Low concentration group preferentially up-regulated genes related to muscle function, potentially supporting locomotion and competitive ability. This study provides new insights into the regulatory mechanism of sesquiterpenoid hormones in crustaceans and their potential applications in aquaculture in the future. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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20 pages, 5769 KiB

Open AccessArticle

Antioxidant Capacity and Disease Resistance Enhanced by Dietary D-Glucuronolactone Supplementation in Chinese Soft-Shelled Turtles (Pelodiscus sinensis)

by Tong Zhou, Wenyi Wu, Mingyang Xue, Yong Zhou, Hongwei Liang and Wei Liu

Antioxidants 2025, 14(5), 534; https://doi.org/10.3390/antiox14050534 - 29 Apr 2025

Viewed by 351

Abstract

D-glucuronolactone (DGL), a hepatoprotective compound widely used in clinical and energy products, was evaluated for its effects on Chinese soft-shelled turtles (Pelodiscus sinensis) through an 8-week feeding trial with dietary supplementation (0, 200, and 400 mg kg⁻¹). DGL did [...] Read more.

D-glucuronolactone (DGL), a hepatoprotective compound widely used in clinical and energy products, was evaluated for its effects on Chinese soft-shelled turtles (Pelodiscus sinensis) through an 8-week feeding trial with dietary supplementation (0, 200, and 400 mg kg⁻¹). DGL did not alter survival or feed intake, but induced dose-dependent growth improvements, including increased final body weight, weight gain rate, specific growth rate, and muscle/liver glycogen, alongside reduced feed conversion ratio and muscle and liver fat. Serum analysis showed decreased activities of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and reduced low-density lipoprotein cholesterol, total cholesterol, and triacylglycerols. Antioxidant indices revealed elevated catalase and superoxide dismutase (SOD) activities in serum and intestine, coupled with reduced malondialdehyde, though hepatic SOD activity declined. Histologically, 400 mg kg⁻¹ DGL alleviated liver lesions without impacting intestinal morphology. Molecular analyses demonstrated upregulated muscle mTOR signaling genes (mTOR, IGF1, S6K1) but downregulated hepatic/intestinal mTOR and IGF1 expression. DGL also suppressed inflammatory cytokines (TNF-α, IL-1β, IL-10) in liver and intestine. Challenge tests with Aeromonas hydrophila confirmed the enhanced disease resistance in DGL-supplemented turtles. These findings highlight DGL’s potential as a nutritional strategy to enhance growth, antioxidant capacity, and health in intensive turtle farming. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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27 pages, 12816 KiB

Open AccessArticle

Differential Cell Death Pathways Induced by Oxidative Stress in Multi-Organs of Amur Grayling (Thymallus grubii) Under Gradient Ammonia Stress

by Cunhua Zhai, Yutao Li, Ruoyu Wang, Ying Zhang and Bo Ma

Antioxidants 2025, 14(4), 499; https://doi.org/10.3390/antiox14040499 - 21 Apr 2025

Viewed by 526

Abstract

Ammonia nitrogen is a common contaminant in aquatic environments, and its potential toxicity to organisms has attracted extensive attention. However, few studies have comprehensively evaluated the negative impacts of ammonia stress on cold-water fish. In this study, liver, gill, and intestine specimens of [...] Read more.

Ammonia nitrogen is a common contaminant in aquatic environments, and its potential toxicity to organisms has attracted extensive attention. However, few studies have comprehensively evaluated the negative impacts of ammonia stress on cold-water fish. In this study, liver, gill, and intestine specimens of Amur grayling (Thymallus grubii) from three treatment groups (control (0 mg/L), low ammonia (43.683 mg/L), and high ammonia (436.8 mg/L)), were collected for histological observation, biochemical examination, and transcriptomic, metabolomic, and intestinal microbiome analysis. Our results showed that excessive ammonia nitrogen blocked the normal immune function and compromised the integrity of liver and gill tissues through oxidative stress-mediated differential cell death pathways. Meanwhile, the multi-omics analysis revealed that ammonia exposure predominantly altered the carbohydrate, lipid, and amino acid metabolism modes. In addition, it was also demonstrated that ammonia nitrogen stress affected the composition of intestinal microbiota taxa. This study provides insights into the potential risks and hazards of ammonia stress on cold fish in natural waters and provides a reference for the environment control of the water quality in aquaculture. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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14 pages, 4506 KiB

Open AccessArticle

Effects of Ammonia Stress on the Antioxidant, Ferroptosis, and Immune Response in the Liver of Golden Pompano Trachinotus ovatus

by Yafei Duan, Meng Xiao, Ruijie Zhu, Yuxiu Nan, Yukai Yang, Xiaohua Huang and Dianchang Zhang

Antioxidants 2025, 14(4), 419; https://doi.org/10.3390/antiox14040419 - 31 Mar 2025

Viewed by 457

Abstract

Ammonia is the main harmful environmental substance affecting fish culture. The liver is the immune and metabolic organ of fish, and its physiological homeostasis will affect the health of the organism. In this study, healthy golden pompano Trachinotus ovatus juveniles were exposed to [...] Read more.

Ammonia is the main harmful environmental substance affecting fish culture. The liver is the immune and metabolic organ of fish, and its physiological homeostasis will affect the health of the organism. In this study, healthy golden pompano Trachinotus ovatus juveniles were exposed to 5 mg/L (A5) and 10 mg/L (A10) ammonia-N stress for 7 days and then the variation characteristics of the physiological homeostasis of the liver were analyzed at multiple biological levels. After ammonia stress, the liver showed obvious morphological changes and stress responses. Specifically, the oxidative stress indexes, such as the activities of the anti-superoxide anion generation capacity (ASC) and superoxide dismutase (SOD), were elevated in the A5 and A10 groups, while the glutathione peroxidase (GPx) activity and glutathione (GSH) content were disturbed; the relative expression levels of the Nrf2 and NQO1 genes were increased in the A10 group, while the expressions of the Keap1 and HO1 were decreased in the A5 and A10 groups. Ferroptosis related genes, such as the relative expressions of NOX1, NCOA4, and FPN1 were increased in the A5 and A10 groups, PTGS2 and FTH1 were decreased in the A5 group but elevated in the A10 group, and p53, GPx4, SLC7A11, and NFS1 were only increased in the A10 group. Inflammation related genes, such as TNFα, IL1β, and IL8 relative expression levels, were increased in the A10 group, IL10 was increased in the A5 and A10 groups, while TGFβ was decreased in the A5 group but increased in the A10 group. Immune related genes, such as the expression levels of IgM and IgT, were increased in the A5 group but decreased in the A10 group. The integrated biomarker responses revealed that the hepatotoxicity of ammonia was concentration-dependent, and there was a high correlation between oxidative stress, ferroptosis, inflammation, and immune function changes. These results reveal the hepatotoxicity of ammonia stress on T. ovatus. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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19 pages, 10474 KiB

Open AccessArticle

The Effects of Acute Temperature Changes on Transcriptomic Responses in the Liver of Leopard Coral Groupers (Plectropomus leopardus)

by Yilan Guo, Chaofan Jin, Cun Wei, Kangning Zhong, Yurui Gao, Peiyu Li, Zhe Qu, Zhenmin Bao, Bo Wang and Jingjie Hu

Antioxidants 2025, 14(2), 223; https://doi.org/10.3390/antiox14020223 - 15 Feb 2025

Viewed by 769

Abstract

The leopard coral grouper (Plectropomus leopardus) is a commercially significant tropical marine species. With the ongoing effects of global climate change, increasing attention has been focused on leopard coral grouper’s susceptibility to extreme cold weather. This study investigates the effects of [...] Read more.

The leopard coral grouper (Plectropomus leopardus) is a commercially significant tropical marine species. With the ongoing effects of global climate change, increasing attention has been focused on leopard coral grouper’s susceptibility to extreme cold weather. This study investigates the effects of acute cold exposure and temperature recovery on the liver of P. leopardus. Histological observations and enzyme activity assays revealed that temperature fluctuations caused significant disruptions to normal liver physiology, including lipid accumulation and alterations in antioxidant levels. Transcriptomic analysis of liver tissue identified 2744 differentially expressed genes (DEGs) across three experimental groups: 25 °C (control), 13 °C (cold exposure), and rewarming at 25 °C (R-25 °C). Functional enrichment analysis revealed that these DEGs were significantly associated with biological processes such as lipid metabolism and antioxidant defense, as well as pathways related to metabolism, fatty acid biosynthesis, and ferroptosis. Furthermore, dynamic regulation of lipid metabolism, immune responses, and oxidative stress pathways was observed in response to both cold stress and rewarming. Notably, several redox-related DEGs were identified, and their interactions with lipid metabolism were further explored. Additionally, representative DEGs associated with antioxidants and lipid metabolism, such as got1, gpx1a, gpt, and g6pcla.2, were validated by qRT-PCR and fluorescence in situ hybridization (FISH). Taken together, this study provides a systematic analysis of the effects of acute cold exposure and temperature recovery stress on the liver of the leopard coral grouper, laying the groundwork for further research on the temperature stress responses in teleost species. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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18 pages, 7306 KiB

Open AccessArticle

The Regulation of γ-Aminobutyric Acid on Antioxidative Defense Response of Pacific Oyster upon High-Temperature Stress

by Ranyang Liu, Lei Gao, Xueshu Zhang, Pingan Ge, Ling Wang, Keli Zhou, Chuanyan Yang, Lingling Wang and Linsheng Song

Antioxidants 2025, 14(2), 222; https://doi.org/10.3390/antiox14020222 - 15 Feb 2025

Viewed by 684

Abstract

Recent studies have found that high temperatures cause oxidative stress and even mass mortality in Pacific oysters (Crassostrea gigas). The role of γ-aminobutyric acid (GABA) in improving antioxidative defense in aquatic animals is increasingly of interest. In the present study, the [...] Read more.

Recent studies have found that high temperatures cause oxidative stress and even mass mortality in Pacific oysters (Crassostrea gigas). The role of γ-aminobutyric acid (GABA) in improving antioxidative defense in aquatic animals is increasingly of interest. In the present study, the oxidative stress of Pacific oysters to high-temperature stress was examined, and the regulation of GABA on the antioxidative defense was further investigated. Following 6 h of exposure to 28 °C seawater, a significant increase in the mRNA expression levels of nuclear factor-E2-related factor 2 (Nrf2), superoxide dismutase (SOD), and catalase (CAT), as well as the activities of SOD and CAT, was observed in the gill, compared to those at 0 h. An increase of glutamate decarboxylase (GAD), GABA receptor (GABA_AR-α and GABA_BR-B) mRNA levels, and GABA contents were also detected after 28 °C exposure compared to those at 0 h. Furthermore, the activities and mRNA expression levels of SOD and CAT were significantly upregulated after GABA treatment, while decreased after either GAD inhibitor or GABA receptor inhibitor treatment under high-temperature stress. Meanwhile, the enhanced effects of GABA on antioxidant enzyme activities were reduced when Nrf2 was inhibited by ML385, accompanied by an increase in MDA content. After high-temperature stress, compared with the GABA treatment group, the activities and mRNA expression levels of SOD and CAT were significantly upregulated by GSK-3β inhibitor treatment. Meanwhile, the elevation of antioxidant enzyme activities by GABA was attenuated by the AKT inhibitor treatment. Collectively, GABA first activated GABA receptors under high-temperature stress and then increased the activities of SOD and CAT and reduced MDA content by AKT/GSK-3β and Nrf2 pathways to protect the oysters against oxidative damage upon stress. The present results offer new insights for understanding the regulation mechanisms of antioxidative defense by the neuroendocrine system in molluscs. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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22 pages, 5902 KiB

Open AccessArticle

Molecular Response and Metabolic Reprogramming of the Spleen Coping with Cold Stress in the Chinese Soft-Shelled Turtle (Pelodiscus sinensis)

by Liqin Ji, Qing Shi, Yisen Shangguan, Chen Chen, Junxian Zhu, Zhen Dong, Xiaoyou Hong, Xiaoli Liu, Chengqing Wei, Xinping Zhu and Wei Li

Antioxidants 2025, 14(2), 217; https://doi.org/10.3390/antiox14020217 - 14 Feb 2025

Viewed by 835

Abstract

The Chinese soft-shelled turtle (Pelodiscus sinensis), as a type of warm-water reptile, could be induced to massive death by sharp temperature decline. Hence, the mechanism of spleen tissue responding to cold stress in the P. sinensis was investigated. The present results [...] Read more.

The Chinese soft-shelled turtle (Pelodiscus sinensis), as a type of warm-water reptile, could be induced to massive death by sharp temperature decline. Hence, the mechanism of spleen tissue responding to cold stress in the P. sinensis was investigated. The present results showed that the superoxide dismutase (SOD) activity declined from 4 to 16 days post-cold-stress (dps), while the catalase (CAT) and glutathione peroxidase (GSH-Px) activities increased, from 4 to 8 dps in the 14 °C (T14) and 7 °C (T7) stress groups. The spleen transcriptome in the T7 group and the control group (CG) at 4 dps obtained 2625 differentially expressed genes (DEGs), including 1462 upregulated and 1663 downregulated genes. The DEGs were enriched mainly in the pathways “intestinal immune network for IgA production” (Pigr, Il15ra, Tnfrsf17, Aicda, and Cd28), “toll-like receptor signaling pathway” (Mapk10, Tlr2, Tlr5, Tlr7, and Tlr8), and “cytokine–cytokine receptor interaction” (Cx3cl1, Cx3cr1, Cxcl14, Cxcr3, and Cxcr4). The metabolomic data showed that esculentic acid, tyrosol, diosgenin, heptadecanoic acid, and 7-ketodeoxycholic acid were obviously increased, while baccatin III, taurohyocholate, parthenolide, enterolactone, and tricin were decreased, in the CG vs. T7 comparison. Integrated analysis of the two omics revealed that “glycine, serine and threonine metabolism”, “FoxO signaling pathway”, and “neuroactive ligand–receptor interaction” were the main pathways responding to the cold stress. Overall, this work found that low temperature remarkably influenced the antioxidant enzyme activities, gene expression pattern, and metabolite profile in the spleen, indicating that immunity might be weakened by cold stress in P. sinensis. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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16 pages, 3658 KiB

Open AccessArticle

Molecular and Physiological Responses of Litopenaeus vannamei to Nitrogen and Phosphorus Stress

by Qianqian Zhao, Cun Wei, Jiangling Dou, Yue Sun, Qifan Zeng and Zhenmin Bao

Antioxidants 2025, 14(2), 194; https://doi.org/10.3390/antiox14020194 - 8 Feb 2025

Cited by 1 | Viewed by 767

Abstract

Environmental stressors such as nitrogen and phosphorus play a critical role in regulating the growth and physiological functions of Litopenaeus vannamei, a key species in aquaculture. This study investigates the effects of nitrogen and phosphorus stress on shrimp growth, oxidative stress, tissue [...] Read more.

Environmental stressors such as nitrogen and phosphorus play a critical role in regulating the growth and physiological functions of Litopenaeus vannamei, a key species in aquaculture. This study investigates the effects of nitrogen and phosphorus stress on shrimp growth, oxidative stress, tissue damage, and molecular mechanisms. Exposure to increasing concentrations of nitrogen and phosphorus significantly reduced growth rates. Oxidative stress markers, including superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (T-AOC), and malondialdehyde (MDA), indicated heightened oxidative damage under both stress conditions, with nitrogen stress causing more severe responses than phosphorus stress. Histopathological analysis revealed substantial damage to the gills and hepatopancreas, organs essential for respiration and metabolism. Transcriptomic analysis identified differentially expressed genes (DEGs) enriched in apoptosis, lysosome, sphingolipid metabolism, and phagosome pathways, suggesting shared molecular responses to nitrogen and phosphorus stress. The results demonstrate that L. vannamei initiates oxidative and immune responses to cope with environmental stressors, but the adaptive capacity remains limited. These findings provide a foundation for understanding the stress tolerance mechanisms in shrimp and inform future strategies for breeding high-resistance strains in aquaculture. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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26 pages, 25856 KiB

Open AccessArticle

TORC1 Regulates Thermotolerance via Modulating Metabolic Rate and Antioxidant Capacity in Scallop Argopecten irradians irradians

by Longfei Chu, Ancheng Liu, Jiaxi Chang, Junhao Zhang, Xiujiang Hou, Xinghai Zhu, Qiang Xing and Zhenmin Bao

Antioxidants 2024, 13(11), 1359; https://doi.org/10.3390/antiox13111359 - 6 Nov 2024

Cited by 1 | Viewed by 1055

Abstract

Target of rapamycin complex 1 (TORC1) is a key regulator of metabolism in eukaryotes across multiple pathways. Although TORC1 has been extensively studied in vertebrates and some invertebrates, research on this complex in scallops is limited. In this study, we identified the genes [...] Read more.

Target of rapamycin complex 1 (TORC1) is a key regulator of metabolism in eukaryotes across multiple pathways. Although TORC1 has been extensively studied in vertebrates and some invertebrates, research on this complex in scallops is limited. In this study, we identified the genes encoding TORC1 complex subunits in the scallop Argopecten irradians irradians through genome-wide in silico scanning. Five genes, including TOR, RAPTOR, LST8, DEPTOR, and PRAS40, that encode the subunits of TORC1 complex were identified in the bay scallop. We then conducted structural characterization and phylogenetic analysis of the A. i. irradians TORC1 (AiTORC1) subunits to determine their structural features and evolutionary relationships. Next, we analyzed the spatiotemporal expressions of AiTORC1-coding genes during various embryo/larvae developmental stages and across different tissues in healthy adult scallops. The results revealed stage- and tissue-specific expression patterns, suggesting diverse roles in development and growth. Furthermore, the regulation of AiTORC1-coding genes was examined in temperature-sensitive tissues (the mantle, gill, hemocyte, and heart) of bay scallops exposed to high-temperature (32 °C) stress over different durations (0 h, 6 h, 12 h, 24 h, 3 d, 6 d, and 10 d). The expression of AiTORC1-coding genes was predominantly suppressed in the hemocyte but was generally activated in the mantle, gill, and heart, indicating a tissue-specific response to heat stress. Finally, functional validation was performed using the TOR inhibitor rapamycin to suppress AiTORC1, leading to an enhanced catabolism, a decreased antioxidant capacity, and a significant reduction in thermotolerance in bay scallops. Collectively, this study elucidates the presence, structural features, evolutional relationships, expression profiles, and roles in antioxidant capacity and metabolism regulation of AiTORC1 in the bay scallop, providing a preliminary understanding of its versatile functions in response to high-temperature challenges in marine mollusks. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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16 pages, 2604 KiB

Open AccessArticle

Carnosine Synthase (TsATPGD) Alleviates Lipid Peroxidation Under Transcriptional Control by an Nfe2-like Gene in Tridacna Squamosa

by Zhuo Yang, Nai-Kei Wong, Fan Mao, Siwei Wu, Wenjie Yi, Ziniu Yu and Yang Zhang

Antioxidants 2024, 13(11), 1351; https://doi.org/10.3390/antiox13111351 - 4 Nov 2024

Viewed by 1201

Abstract

As an important mollusk in reef ecosystems, Tridacna squamosa forms pro-survival symbiotic relationships that hinge on an exquisite redox equilibrium between the host and the photosynthetic symbiont, zooxanthellae. The exact regulatory mechanisms thereof remain poorly understood. In this study, a novel Nfe2-like transcription [...] Read more.

As an important mollusk in reef ecosystems, Tridacna squamosa forms pro-survival symbiotic relationships that hinge on an exquisite redox equilibrium between the host and the photosynthetic symbiont, zooxanthellae. The exact regulatory mechanisms thereof remain poorly understood. In this study, a novel Nfe2-like transcription factor in T. squamosa was identified and characterized with respect to its antioxidant and cytoprotective roles. Gene structure and phylogenetic analysis reveal that T. squamosa possesses a single transcription factor TsNfe2l in contrast to mammalian Nfe2l1 (Nrf1) and Nfe2l2 (Nrf2), belonging to protein members of the bZIP-NFE2 subfamily and functionally resembling the mammalian Nfe2l1. A conserved bZIP domain permits its binding to the antioxidant response element (ARE) in vitro and in HEK293T cells. Further analyses such as promoter prediction suggest that TsNfe2l target genes engage mainly in the regulation of multiple enzymes involved in antioxidation and allied pathways. Notably, TsNfe2l transcriptionally upregulates carnosine synthase (TsATPGD), which subsequently produces L-carnosine abundantly to shield cells from oxidative damage. Moreover, the blockage of TsNfe2l nucleic acid binding reduced the expression of TsATPGD and L-carnosine content in the gill, resulting in elevated lipid peroxidation. Collectively, our findings establish novel molecular insight into TsNfe2l as a critical regulator of redox homeostasis in T. squamosa through carnosine synthesis. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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16 pages, 4146 KiB

Open AccessArticle

Effects of Nitrite Stress on the Antioxidant, Immunity, Energy Metabolism, and Microbial Community Status in the Intestine of Litopenaeus vannamei

by Yafei Duan, Guowei Zhong, Yuxiu Nan, Yukai Yang, Meng Xiao and Hua Li

Antioxidants 2024, 13(11), 1318; https://doi.org/10.3390/antiox13111318 - 29 Oct 2024

Cited by 6 | Viewed by 1487

Abstract

Nitrite is the main environmental pollutant that endangers shrimp culture. Intestinal health is essential for the disease resistance of shrimp. In this study, Litopenaeus vannamei shrimps were separately exposed to 1 and 5 mg/L of nitrite stress for 48 h, and then the [...] Read more.

Nitrite is the main environmental pollutant that endangers shrimp culture. Intestinal health is essential for the disease resistance of shrimp. In this study, Litopenaeus vannamei shrimps were separately exposed to 1 and 5 mg/L of nitrite stress for 48 h, and then the variations in intestinal health were investigated from the aspects of histology, antioxidant, immunity, energy metabolism, and microbial community status. The results showed that nitrite stress damaged intestinal mucosa, and 5 mg/L of nitrite induced more obvious physiological changes than 1 mg/L. Specifically, the relative expression levels of antioxidant (ROMO1, Nrf2, SOD, GPx, and HSP70), ER stress (Bip and XBP1), immunity (proPO, Crus, ALF, and Lys), inflammation (JNK and TNF-α), and apoptosis (Casp-3 and Casp-9) genes were increased. Additionally, intestinal energy metabolism was activated by inducing glucose metabolism (HK, PK, PDH, and LDH), lipid metabolism (AMPK and FAS), tricarboxylic acid cycle (MDH, CS, IDH, SDH, and FH), and electron transfer chain (NDH, CytC, COI, CCO, and AtpH) gene transcription. Further, the homeostasis of intestinal microbiota composition was also disturbed, especially the abundance of some beneficial genera (Clostridium sensu stricto 1, Faecalibacterium, Romboutsia, and Ruminococcaceae UCG-010). These results reveal that nitrite stress could damage the intestinal health of L. vannamei by destroying mucosal integrity, inducing oxidation and ER stress, interfering with physiological homeostasis and energy metabolism, and disrupting the microbial community. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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18 pages, 6589 KiB

Open AccessArticle

Microplastic-Enhanced Cadmium Toxicity: A Growing Threat to the Sea Grape, Caulerpa lentillifera

by Weilong Zhou, Haolong Zheng, Yingyin Wu, Junyi Lin, Xiaofei Ma, Yixuan Xing, Huilong Ou, Hebert Ely Vasquez, Xing Zheng, Feng Yu and Zhifeng Gu

Antioxidants 2024, 13(10), 1268; https://doi.org/10.3390/antiox13101268 - 18 Oct 2024

Cited by 1 | Viewed by 1844

Abstract

The escalating impact of human activities has led to the accumulation of microplastics (MPs) and heavy metals in marine environments, posing serious threats to marine ecosystems. As essential components of oceanic ecosystems, large seaweeds such as Caulerpa lentillifera play a crucial role in [...] Read more.

The escalating impact of human activities has led to the accumulation of microplastics (MPs) and heavy metals in marine environments, posing serious threats to marine ecosystems. As essential components of oceanic ecosystems, large seaweeds such as Caulerpa lentillifera play a crucial role in maintaining ecological balance. This study investigated the effects of MPs and cadmium (Cd) on the growth, physiology, biochemistry, and Cd accumulation in C. lentillifera while elucidating the underlying molecular regulatory mechanisms. The results demonstrated that exposure to MPs alone significantly promoted the growth. In contrast, exposure to Cd either alone or in combination with MPs significantly suppressed growth by reducing stem and stolon length, bud count, weight gain, and specific growth rates. Combined exposure to MPs and Cd exhibited the most pronounced inhibitory effect on growth. MPs had negligible impact while Cd exposure either alone or combined with MPs impaired antioxidant defenses and exacerbated oxidative damage; with combined exposure being the most detrimental. Analysis of Cd content revealed that MPs significantly increased Cd accumulation in algae intensifying its toxic effects. Gene expression analysis revealed that Cd exposure down-regulated key genes involved in photosynthesis, impairing both photosynthetic efficiency and energy conversion. The combined exposure of MPs and Cd further exacerbated these effects. In contrast, MPs alone activated the ribosome pathway, supporting ribosomal stability and protein synthesis. Additionally, both Cd exposure alone or in combination with MPs significantly reduced chlorophyll B and soluble sugar content, negatively impacting photosynthesis and nutrient accumulation. In summary, low concentrations of MPs promoted C. lentillifera growth, but the presence of Cd hindered it by disrupting photosynthesis and antioxidant mechanisms. Furthermore, the coexistence of MPs intensified the toxic effects of Cd. These findings enhance our understanding of how both MPs and Cd impact large seaweed ecosystems and provide crucial insights for assessing their ecological risks. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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16 pages, 3824 KiB

Open AccessArticle

Comparative Analyses of Dynamic Transcriptome Profile of Heart Highlight the Key Response Genes for Heat Stress in Zhikong Scallop Chlamys farreri

by Xinyuan Wang, Zujing Yang, Cheng Peng, Haitao Yu, Chang Cui, Qiang Xing, Jingjie Hu, Zhenmin Bao and Xiaoting Huang

Antioxidants 2024, 13(10), 1217; https://doi.org/10.3390/antiox13101217 - 10 Oct 2024

Cited by 2 | Viewed by 1287

Abstract

Heat stress resulting from global climate change has been demonstrated to adversely affect growth, development, and reproduction of marine organisms. The Zhikong scallop (Chlamys farreri), an important economical mollusk in China, faces increasing risks of summer mortality due to the prolonged [...] Read more.

Heat stress resulting from global climate change has been demonstrated to adversely affect growth, development, and reproduction of marine organisms. The Zhikong scallop (Chlamys farreri), an important economical mollusk in China, faces increasing risks of summer mortality due to the prolonged heat waves. The heart, responsible for transporting gas and nutrients, is vital in maintaining homeostasis and physiological status in response to environmental changes. In this study, the effect of heat stress on the cardiac function of C. farreri was investigated during the continuous 30-day heat stress at 27 °C. The results showed the heart rate of scallops increased due to stress in the initial phase of high temperature exposure, peaking at 12 h, and then gradually recovered, indicating an acclimatization at the end of the experiment. In addition, the levels of catalase (CAT), superoxide dismutase (SOD), and total antioxidant capacity (T-AOC) exhibited an initial increase followed by recovery in response to heat stress. Furthermore, transcriptome analysis of the heart identified 3541 differentially expressed genes (DEGs) in response to heat stress. Subsequent GO and KEGG enrichment analysis showed that these genes were primarily related to signal transduction and oxidative stress, such as the phosphatidylinositol signaling system, regulation of actin cytoskeleton, MAPK signaling pathway, FoxO signaling pathway, etc. In addition, two modules were identified as significant responsive modules according to the weighted gene co-expression network analysis (WGCNA). The upregulation of key enzymes within the base excision repair and gap junction pathways indicated that the heart of C. farreri under heat stress enhanced DNA repair and maintained cellular integrity. In addition, the variable expression of essential signaling molecules and cytoskeletal regulators suggested that the heart of C. farreri modulated cardiomyocyte contraction, intracellular signaling, and heart rate through complex regulation of phosphorylation and calcium dynamics in response to heat stress. Collectively, this study enhances our understanding of cardiac function and provides novel evidence for unraveling the mechanism underlying the thermal response in mollusks. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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17 pages, 8177 KiB

Open AccessArticle

Antioxidant Capacity, Enzyme Activities Related to Energy Metabolism, and Transcriptome Analysis of Crassostrea hongkongensis Exposed to Hypoxia

by Pingping He, Wei Li, Pinyuan Wei, Linyuan Jiang, Junliang Guan, Yuan Ma, Li Zhang, Yongxian Chen, Yusi Zheng, Xingzhi Zhang and Jinxia Peng

Antioxidants 2024, 13(9), 1063; https://doi.org/10.3390/antiox13091063 - 30 Aug 2024

Cited by 1 | Viewed by 1568

Abstract

Crassostrea hongkongensis (C. hongkongensis) is one of the three most commonly cultivated oyster species in China. Seasonal hypoxia is one of the most serious threats to its metabolism, reproductive behavior, and survival. To investigate the effects of hypoxia stress on the [...] Read more.

Crassostrea hongkongensis (C. hongkongensis) is one of the three most commonly cultivated oyster species in China. Seasonal hypoxia is one of the most serious threats to its metabolism, reproductive behavior, and survival. To investigate the effects of hypoxia stress on the antioxidant capacity and energy metabolism of C. hongkongensis, the total antioxidant capacity (T-AOC), glycogen content, and enzyme activities (phosphofructokinase, PFK; pyruvate kinase, PK; phosphoenolpyruvate carboxykinase, PEPCK) of oysters were determined under normoxic (DO 6 ± 0.2 mg/L) and hypoxic (DO 1.5 mg/L) conditions at 0 h, 6 h, 48 h, and 72 h. We also determined the T-AOC, glycogen content, and enzyme activities of oysters under reoxygenation (recovered to normoxia for 24 h). To further examine the potential molecular regulatory mechanism of hypoxic adaptation, a transcriptome analysis was conducted on the gill of C. hongkongensis under normoxia (N, 72 h), hypoxia (H, 72 h), and reoxygenation (R). After being exposed to hypoxia for 6 h, the T-AOC, glycogen content, and enzyme activities of PK, PFK, and PEPCK in C. hongkongensis were significantly decreased. However, after prolonging the duration of hypoxia exposure for 72 h, the T-AOC, glycogen content, and enzyme activities increased compared to that of 48 h. After 24 h reoxygenation, the T-AOC, glycogen content, and enzyme activity of PK and PFK returned to close to initial levels. In addition, a transcriptome analysis discovered 6097 novel genes by mapping the C. hongkongensis genome with the clean reads. In total, 352 differentially expressed genes (DEGs) were identified in the H vs. N comparison group (235 upregulated and 117 downregulated genes). After recovery to normoxia, 292 DEGs (134 upregulated and 158 downregulated genes) were identified in the R vs. N comparison group, and 632 DEGs were identified (253 upregulated and 379 downregulated genes) in the R vs. H comparison group. The DEGs included some hypoxia-tolerant genes, such as phosphoenolpyruvate carboxykinase (PEPCK), mitochondrial (AOX), tyramine beta-hydroxylase (TBH), superoxide dismutase (SOD), glutathione S-transferase (GST), and egl nine homolog 1 isoform X2 (EGLN1). Additionally, DEGs were significantly enriched in the KEGG pathways that are involved in hypoxia tolerance, including the metabolism of xenobiotics by cytochrome P450 pathways and the HIF-1 signaling pathway. Then, we selected the five hypoxic-tolerant candidate DEGs for real-time quantitative polymerase chain reaction (RT-qPCR) validation, and the results were consistent with the transcriptome sequencing data. These discoveries have increased our understanding of hypoxia tolerance, recovery ability after reoxygenation, and molecular mechanisms governing the responses to hypoxia in C. hongkongensis. Full article

(This article belongs to the Special Issue The Role of Oxidative Stress in Aquaculture)

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