Sea Cucumber Research Articles

Machine learning for potential anti-cancer discovery from black sea cucumbers

<p>Despite being an abundant marine organism in Indonesia, black sea cucumbers <em>(Holothuria atra)</em> is still underutilised due to its slightly bitter taste. This study aims to identify potential anti-cancer compounds from black sea cucumbers using machine learning (ML) to perform drug discovery. ML models were used to predict interactions between compounds from the organism with cancer-related proteins. Following prediction, all compounds were computationally validated through molecular docking. The validated compounds were then screened using absorption, distribution, metabolism, excretion, and toxicity (ADMET) Lab 2.0 to assess their druglike properties. The results showed that ML predicted seven out of 86 compounds were interacted with cancer-related proteins. Computational validation from the results showed that four out of seven compounds demonstrated stable interaction with proteins where only one compound meet the criteria of drug-like compound. The framework of ML and computational validation highlighted in this study shows a great promise in the future of drug discovery specifically for marine organisms. Since computational method only works in prediction realms, wet lab validation and clinical trials are imperative before the drug candidate can be produced as actual anti-cancer drug.</p>

A Multi-Scale Convolutional Hybrid Attention Residual Network for Enhancing Underwater Image and Identifying Underwater Multi-Scene Sea Cucumber

A Multi-Scale Convolutional Hybrid Attention Residual Network for Enhancing Underwater Image and Identifying Underwater Multi-Scene Sea Cucumber

Development of Reliable Male-Specific Molecular Markers for Genetic Sex Identification in Sea Cucumber Apostichopus japonicus.

Apostichopus japonicus is an important marine aquaculture species in China, with high nutritional and economic value. In A. japonicus, there is no obvious sexual dimorphism in external appearance, and sex differentiation primarily relies on the observation of mature gonads after dissection, which leads to difficulties in sex identification. The confusion in sex identification greatly reduces breeding efficiency in the sea cucumber industry. Therefore, developing a reliable sex-specific marker is crucial. In this study, we identified 586 male-specific sequences through whole-genome assembly and sequence alignment, but did not identify any female-specific sequences, inferring an XY-type sex determination system in sea cucumbers. We developed a set of male-specific molecular markers to establish an accurate, stable, and widely adaptable genetic sex identification technique for A. japonicus. The male-specific molecular markers were validated with 100% accuracy in sea cucumber populations from six different geographical regions in China. In conclusion, this study provides further evidence for the XY-type sex determination system in A. japonicus and establishes an effective genetic sex identification method for multi-geographic populations, which benefits future study on reproductive biology and has significant implications in sea cucumber aquaculture industry.

Reproductive biology of the commercial sea cucumber Holothuria (Roweothuria) poli, in the Central Aegean Sea, Greece

Holothuria poli is one of the most in-demand sea cucumber species and has attracted the interest of markets in Mediterranean regions. The present study is the first attempt to determine the reproductive cycle of H. poli in a coastal area of the Central Aegean Sea. Samples of H. poli as well as environmental and biometric data were collected monthly for 1 year. The sample population exhibited a female predominance, a size at first maturation of 156.3 mm and a distinctive reproductive pattern that reached its mature stage in the summer months. These findings contribute to the overall understanding of the reproductive physiology of the species and provide information for the sustainable management of sea cucumber stocks in the Hellenic Seas.

Identification and molecular mechanism of the anti-inflammatory effect of sea cucumber peptides: Network pharmacology, molecular docking and animal experiments

Ulcerative colitis (UC) is a chronic inflammatory bowel disease for which there is currently no efficacious therapeutic drug with fewer side effects. Therefore, the development of approaches for the prevention of UC from natural food sources is urgently needed. In this study, mice were pre-fed with sea cucumber peptides prior to dextran sodium sulfate (DSS) induction. Results showed that sea cucumber peptides decreased pro-inflammatory cytokine (IL-4 and IL-10) levels and remissions of main clinic symptoms in a dose-dependent manner. The composition of peptides was identified, and the anti-inflammatory molecular mechanism was evaluated by silico prediction. The molecular weight of the peptides was 243–1800 Da and composed of 3–18 amino acid residues. Online activity assessment and molecular docking prediction revealed that tripeptides of FGI, FLI, FLL, GFL, GFM, IGF and LDF exhibited strong anti-inflammatory activity. Particularly, LDF showed the highest potency, with a binding energy of −5.37 kJ/mol. Network pharmacology analysis of UC related diseases indicated that active peptides interact with colitis disease targets, primarily proto-oncogene tyrosine-protein kinase Src (SRC), E3 ubiquitin-protein ligase XIAP (XIAP) and angiotensin-converting enzyme (ACE). The results suggest that sea cucumber peptides have potential as a novel nutraceutical option for colitis relief.

Genetic structure of a population of “peanutfish” (“dragonfish”) sea cucumbers using mitochondrial COI sequences in Marau, Guadalcanal, Solomon Islands

Genetic structure of a population of “peanutfish” (“dragonfish”) sea cucumbers using mitochondrial COI sequences in Marau, Guadalcanal, Solomon Islands

Physicochemical Properties, Functionalities, and Antioxidant Activity of Protein Extracts from New Zealand Wild Sea Cucumbers (Australostichopus mollis).

This study investigated the physicochemical properties, functionalities, and antioxidant capacities of protein extracts from wild sea cucumber Australostichopus mollis collected from four distinct locations in New Zealand. Protein was extracted from sea cucumber body walls using trypsin enzymatic extraction, followed by cold acetone precipitation. The amino acid analysis revealed high glycine (189.08 mg/g), glutamic acid (119.45 mg/g), and aspartic acid (91.91 mg/g) concentrations in all samples. The essential amino acid indexes of the protein extracts (62.96, average) were higher than the WHO/FAO standard references, indicating the excellent protein quality of A. mollis. Furthermore, protein extracts from A. mollis demonstrated superior emulsifying activity (202.3-349.5 m2/g average) compared to commercial soy and whey protein isolates under all tested pH conditions, and enhanced foaming capacity (109.9-126.4%) and stability (52.7-72%) in neutral and acidic conditions. The extracts also exhibited good solubility, exceeding 70% across pH 3-11. Antioxidant capacities (ABTS and DPPH free radical scavenging activity and ferric reducing antioxidant power) were identified in A. mollis protein extracts for the first time, with clear variations observed among different locations. These findings elucidate the advantageous functional properties of protein extracts from wild New Zealand A. mollis and highlight their potential application as high-quality antioxidant food ingredients.

Identification of novel anti-obesity saponins from the ovary of sea cucumber (Stichopus japonicus)

The potential anti-obesity effects of sea cucumber extract have been reported. However, the individual saponins responsible for these effects are yet to be isolated and characterized. This study aimed to identify the most effective sea cucumber body part for inhibiting lipid accumulation in adipocytes and to elucidate the compounds responsible for this effect using nuclear magnetic resonance (NMR) techniques. Sea cucumber ovary 80 % ethanol extract (SCOE) demonstrated remarkable efficacy in inhibiting adipocyte differentiation compared to other sea cucumber body parts with 50 % or 80 % ethanol extracts. SCOE anti-obesity effect was evaluated in C57BL/6 mice fed a high-fat diet, which revealed significant reductions in body weight, serum lipids, adipose tissue, and liver weight. Using column chromatography, eight saponins were isolated from the SCOE, four of which exhibited potent inhibitory effects on adipocyte differentiation. Of these, three active saponins, holotoxins A, B, and D1, were newly identified. These findings highlight the potential of SCOE and its saponins as effective anti-obesity agents.

Effects of dietary fermented attachments of suspension cage as a replacement for sea mud on growth and intestinal health of sea cucumber Apostichopus japonicus

In the suspension cage culture process, regular cleaning to remove epiphytic organisms from the cage is essential to prevent economic losses due to the sinking of the cage. However, after cleaning, many of attachments from the suspension cage accumulate in the tidal flats, causing environmental pollution and resource wastage. Moreover, because sea cucumbers (Apostichopus japonicus) are sedimentary food organisms, sea mud is typically added to their feed to varying degrees. However, long-term excavation of sea mud can destroy the marine environment. Therefore, developing an alternative new raw feed material to replace sea mud in sea cucumber feed is necessary to promote sustainable development of the A. japonicus aquaculture industry. The aim of this study was to explore the feasibility of using fermented attachments of suspension cage (FASC) as a raw feed material for A. japonicus. Different FASC concentrations (0, 25, 50, 75, and 100 %) were used in A. japonicus feed for 60 d. Replacing Sea mud with 100 % FASC significantly improved sea cucumber growth, reduced the feed coefficient, significantly increased the activity of intestinal digestive enzymes, improved intestinal structure, and enriched intestinal microbiome diversity. Furthermore, expressions of growth genes mapk-7 and fgfr-1 significantly increased in the 100 % FASC treatment compared with that in the control, and that of negative growth regulator gene gdf-8 was inhibited. The results suggested the potential of FASC as a new raw feed material for A. japonicus.

Seizing a venue linking opportunity: China’s strategy to advance its sea cucumber interests in global environmental governance

This study explores how China strategically advances its position and interacts with institutional contexts to shape environmental negotiations. By employing process-tracing methods and conducting expert interviews on the case of sea cucumber negotiations, we find that China intends to garner international support in a policy venue (CITES) while actively engaging in another policy venue that better aligns with China's interests (FAO). Building upon existing studies on institutional change and negotiation strategy, we highlight two aspects of a venue-linking framework, including the institutional settings enabling countries to deploy such a strategy in environmental negotiations and the actors’ capacity to seize the opportunity. In doing so, we show how China has strategically engaged in multiple policy venues to advance its preferences through a particular, more amenable venue. Our findings offer new empirical insights into how China navigates the complex political dynamics in global environmental governance when multiple policy venues with overlapping jurisdictions are involved.

Anti-enterovirus 71 activity of native fucosylated chondroitin sulfates and their derivatives

Enterovirus 71 (EV71) is recognized as a major causative agent of hand, foot, and mouth disease (HFMD), posing a significant global public health concern due to its widespread impact and resulting in a major public health issue worldwide. Despite its prevalence, current clinical therapy lacks effective antiviral agents. Fucosylated chondroitin sulfates (FCS) derived from sea cucumber exhibits a range of biological activities including potent antiviral effects. This study provides compelling evidence of the potent antiviral efficacy of FCS against EV71. To further elucidate the impact of structural variations on the anti-EV71 activity, native FCSs with diverse sulfation patterns and a varity of FCS derivatives were prepared and analyzed. Notably, this study presents the detailed structural characterization of FCSs from the sea cucumbers Holothuria scabra Jaege and Holothuria fuscopunctata. Analysis of the structure-activity relationships revealed that molecular weight, sulfated fucose branches, and sulfation pattern were all crucial factors contributing to the potent inhibitory effects of FCS against EV71. Interestingly, molecular weight emerged as the most significant structural determinant of the antiviral potency. These findings suggest the promising potential of utilizing FCS as an innovative EV71 entry inhibitor for the treatment of HFMD.

Total arsenic and arsenic species in selected seafoods: Analysis using high-performance liquid chromatography- inductively coupled plasma mass spectrometry and health risk assessment

The objective of the present study was to determine the inorganic and organic arsenic species and assess the actual risk of selected seafood produced in Sri Lanka in terms of inorganic arsenic species. A total of 80 samples, comprising 75 seafood samples and 5 freshwater samples, including mollusks, echinoderms, and crustaceans, were analyzed for their total arsenic (TA) levels and arsenic species. TA levels in seafood were determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) after microwave digestion. Arsenic species, including arsenobetaine (AsB), arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA), were selectively separated and quantified using High-Performance Liquid Chromatography (HPLC) coupled to ICP-MS, following water bath extraction with 30 mmol/L nitric acid. The TA levels in seafood ranged from 0.036 to 11.686 mg kg-1. The spike recovery values for the five arsenic species lay within 80 % to 120 %, and the chromatographic recovery percentages ranged from 85.5 % to 123.6 %. In most samples, 100 % AsB was detected. Sea cucumber and both marine and freshwater giant river prawns showed AsB percentages of the total arsenicals at 83.2 %, 39.7 %, and 21.3 %, respectively. DMA was found in sea cucumber and marine giant river prawn at levels of 0.065 mg kg-1 and 0.048 mg kg-1, respectively, while MMA was not detected in any samples. AsIII was found in marine water giant river prawn and freshwater giant river prawn at levels of 0.010 mg kg-1 and 0.044 mg kg-1, respectively. AsV was only found in marine giant river prawn at a concentration of 0.193 mg kg-1. No other samples contained detectable levels of inorganic arsenicals. The Target Hazard Quotient (THQ) values for marine and freshwater giant river prawn were 0.90 and 0.2, respectively, indicating no significant health risks since the THQ values were <1. Therefore, our study suggests that consuming the studied seafood does not pose any health risks in terms of arsenic.

MiR-210, not let-7, regulates Akt gene expression against Vibrio splendidus infection in the sea cucumber Apostichopus japonicus

The immune regulatory roles of microRNAs (miRNAs) have recently attracted considerable attention. Bioinformatics prediction revealed that both let-7 and miR-210 provide potential binding sites for the Akt (rac-alpha serine/threonine-protein kinase) gene sequence in the sea cucumber Apostichopus japonicus (termed AjAkt). In this study, we first used a dual-luciferase reporter assay and functional validation techniques to verify the interactions between these two miRNAs (let-7 and miR-210) and AjAkt, and then investigated the functions of the validated miRNA/mRNA pair as part of the innate immune response against Vibrio splendidus infection. We found that AjAkt interacts with miR-210 rather than let-7, and miR-210 negatively regulates the expression of AjAkt. From 8 to 48 h after infection with V. splendidus, opposite trends were observed in the expression levels of miR-210 and AjAkt (mRNA and protein) in coelomocytes, suggesting that the miR-210/AjAkt pair is involved in immune regulation during this period after infection. Both AjAkt silencing and miR-210 overexpression enhanced the phagocytic capacity and reduced the infectivity of A. japonicus after pathogen infection, suggesting that the miR-210/AjAkt pair may regulate the innate immune response of A. japonicus by altering phagocytic capacity. The findings of this study enrich our knowledge of the role of miRNA/mRNA pairs in immune regulation in sea cucumbers and provide insights into the molecular mechanisms of the innate immune response in marine echinoderms.

Pemantauan Kepadatan Megabentos Target Pada Terumbu Karang di Perairan Leato Selatan Kecamatan Dumbo Raya Provinsi Gorontalo

Megabenthos target associated with coral reefs include spiny starfish, blue starfish, sea urchins, sea cucumber, clams, Drupella spp., trocha snail, and lobsters which is ecologically used as an indicator for monitoring the healt condition of coral reefs and is benefical for the community’s economy.The aim of this research is to determine the density level and distribution pattern of megabenthos target on coral reefs in the waters of South Leato, Dumbo Raya Subdistrict, Gorontalo Province. Method used in collecting megabenthos data is with Bentos Belt Transect. Observation results show that the megabenthos target found in South Leato waters were seven types consisting of sea cucumber, clams, trocha snail, spiny starfish, Drupella spp., sea urchins, and blue starfish. The megabenthos target density range values obtained are 0,007 – 0,435 ind/m2, and for morisita index values ranging 0 - 0,6655 id with the distribution pattern of the megabenthos target found all being unifom.

Novel heterologously expressed protein, AjPSPLP-3, derived from Apostichopus japonicus exhibits cell proliferation and migration activities

Developing more effective bioactive ingredients of natural origin is imperative for promoting wound healing. Sea cucumbers have long enjoyed a good reputation as both food delicacies and traditional medicines. In this study, we heterogeneously expressed a Apostichopus japonicus derived novel protein AjPSPLP-3, which exhibits a theoretical molecular weight of 13.034 kDa, through fusion with maltose binding protein (MBP). AjPSPLP-3 contains a strict CXXCXC motif, nine extremely conserved cysteine residues and two highly conserved cysteine residues. The predicted structure of AjPSPLP-3 consists of random coil and nine β-sheets, Cys30-Cys67, Cys38-Cys58, Cys53-Cys90, Cys56-Cys66, and Cys81-Cys102 participating in the formation of five pairs of disulfide bonds. In vitro experiments conducted on HaCaT cells proved that AjPSPLP-3 and MBP-fused AjPSPLP-3 significantly contribute to HaCaT cells proliferation and migration without exhibiting hemolytic activity on murine erythrocytes. Specifically, treatment with 10 μmol/L MBP-fused AjPSPLP-3 protein increased the viability of HaCaT cells by 12.28 % (p < 0.001), while treatment with 10 μmol/L AjPSPLP-3 protein increased viability of HaCaT cells by 6.01 % (p < 0.01). Furthermore, wound closure of MBP-fused AjPSPLP-3 and AjPSPLP-3 were 22.51 % (p < 0.01) and 7.32 % (p < 0.05) higher than that of the control groups in HaCaT cells following 24 h of incubation.

Sea Cucumber Viscera Processed by Protease Hydrolysis Combined with Cordyceps militaris Fermentation Protect Caco-2 Cells against Oxidative Damage via Enhancing Antioxidant Capacity, Activating Nrf2/HO-1 Pathway and Improving Cell Metabolism.

Excessive reactive oxygen species (ROS) may lead to oxidative damage and metabolic disorder. The pathogenesis of human bowel inflammation is closely related to oxidative damage of intestinal epithelial cells caused by ROS. This study aimed to explore the high-value utilization of the byproducts of sea cucumber in antioxidant food for colitis prevention. The technology of protease hydrolysis combined with Cordyceps militaris fermentation was used to obtain fermented sea cucumber viscera protease hydrolysates (FSVHs). The results revealed that FSVH could enhance antioxidant capacity and alleviate oxidative damage and apoptosis by activating the Nrf2/HO-1 pathway and triggering the self-protection immune mechanisms. Moreover, the FSVH supplementation could upregulate antioxidant-related metabolic pathways of Caco-2 cells such as glutathione metabolism, confirming the enhanced antioxidant capacity of damaged cells. In summary, FSVH could exert protective effects on Caco-2 cells in response to oxidative damage, providing a promising prospect for sea cucumber resource utilization and colitis prevention.

Faster-YOLOv5: real-time deep learning for sea cucumber defect recognition and classification

To tackle the challenges of precise recognition and classification of sea cucumbers in food processing, including issues like external lighting conditions, hardware limitations, and slow inference speeds, we propose a lightweight Faster-YOLOv5 network for the recognition and classification of common sea cucumber defects. Firstly, we utilize the GhostNetV2 network fused with the Mixed Local Channel Attention (MLCA) mechanism as the backbone, enhancing model feature representation and lightweight characteristics to ensure efficient operation in resource-limited environments. Additionally, by introducing an Auxiliary Head (Aux head), we bolster training stability and efficiency, guiding the model to focus on intermediate feature learning, thereby improving generalization and accuracy in detecting various target categories. Lastly, the MPDIoU loss function is employed to optimize the intersection over union between predicted and ground truth bounding boxes, aiming to reduce false detection rates and accelerate model training convergence. The experimental results demonstrate that the network achieves a precision of 96.83% and an mAP@0.5 of 95.12% in sea cucumber recognition, with an inference speed of 82.71 frames per second. This method balances accuracy and inference speed, offering a viable solution for similar problems.

Extraction of Omega-3 Fatty Acids from Atlantic Sea Cucumber (Cucumaria frondosa) Viscera Using Supercritical Carbon Dioxide.

This study explores the potential of Cucumaria frondosa (C. frondosa) viscera as a natural source of omega-3 FAs using supercritical carbon dioxide (scCO2) extraction. The extraction conditions were optimized using a response surface design, and the optimal parameters were identified as 75 °C and 45 MPa, with a 20 min static and a 30 min dynamic extraction, and a 2:1 ethanol to feedstock mass ratio. Under these conditions, the scCO2 extraction yielded higher FAs than the solvent-based Bligh and Dyer method. The comparative analysis demonstrated that scCO2 extraction (16.30 g of FAs/100 g of dried samples) yielded more fatty acids than the conventional Bligh and Dyer method (9.02 g, or 13.59 g of FAs/100 g of dried samples with ultrasonic assistance), indicating that scCO2 extraction is a viable, green alternative to traditional solvent-based techniques for recovering fatty acids. The pre-treatment effects, including drying methods and ethanol-soaking, were investigated. Freeze-drying significantly enhanced FA yields to almost 100% recovery, while ethanol-soaked viscera tripled the FA yields compared to fresh samples, achieving similar EPA and DHA levels to hot-air-dried samples. These findings highlight the potential of sea cucumber viscera as an efficient source of omega-3 FA extraction and offer an alternative to traditional extraction procedures.

A review on the processing technique, physicochemical, and bioactive properties of marine collagen.

Collagens are conventionally derived from bovine and porcine sources. However, these sources were commonly associated with infectious diseases such as bovine spongiform encephalopathy, foot and mouth disease, autoimmune and allergic reactions, and religious constraints. The significant amount of collagen available in marine species, especially fish skins, scales, fins, and bones, shows that marine species can be a potential alternative source to mammalian collagen. Therefore, this review aims to give a clearer outlook on the processing techniques of marine collagen and its physicochemical and bioactive properties as a potential alternative to mammalian collagen. The two most suitable extraction methods for marine collagen are pepsin-soluble extraction and ultrasound-assisted extraction. Additionally, marine collagen's physicochemical and bioactive properties, such as antioxidants, wound healing, tissue engineering, and cosmetic biomaterial have been thoroughly discussed in this review. PRACTICAL APPLICATION: Collagen extracted from marine sources showed its potential in physicochemical and bioactive properties, including antioxidants and wound-healing capabilities, as an alternative to mammalian collagen. The significant amount of collagen found in marine species, particularly in fish skins, scales, bones, and sea cucumbers, suggests that marine sources could be a viable alternative to land mammal collagen due to their abundance and accessibility. The ultrasound-assisted extraction technique has improved the extracted marine collagen's physicochemical and bioactivity properties and quality properties.

Nanoplastics exposure simplifies the network structure of sea cucumber (Apostichopus japonicus) gut microbiota and improves cluster randomness

Nanoplastics (NPs) are abundant in ocean environments, leading to environmental pollution and notable disruptions to the physiological functions of marine animals. To investigate the toxic effects of NPs on echinoderms, specifically sea cucumbers (Apostichopus japonicus), they were exposed to varying concentrations of NPs (0, 102, 104 particles/L) for 14 d. Subsequently, the 102 particles/L exposure group was purified for 35 d to elucidate the impact of both NPs exposure and purification on the intestinal bacteria structure and function. The results showed that the richness and variety of intestinal bacteria in sea cucumbers significantly reduced under NPs exposure, and then they could be restored to the pre-exposure treatment state after 35 d of purification. With the increase of NPs exposure concentration in the environment, the intestinal core bacteria gradually changed from Firmicutes and Proteobacteria to Pseudoalteromonas and Vibrio. The KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway database annotated that the gut microbiota of sea cucumbers was significantly downregulated in the glycosylation, carbohydratic and amino acid metabolic pathways (P < 0. 05), exogenous substance biodegradation and metabolism, DNA replication and repair pathways were significantly up-regulated (P < 0.05) under the exposure of NPs. In addition, nanoplastics exposure simplified the symbiotic network relationships of the gut bacteria, reduced the selective effect of host on the intestinal bacteria, and increased stochasticity. In conclusion, waterborne NPs can adversely affect the structure and function of sea cucumber intestinal bacteria, with these effects persisting for a duration. However, as the purification time lengthens, these adverse effects gradually diminish. This study aims to provide some theoretical basis for the biotoxic effects of NPs.