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Integrated multi-trophic aquaculture, or IMTA, attempts to reduce or eliminate nutrient loading by introducing lower trophic organisms to consume waste matter. These organisms should be capable of consuming bottom detritus with dissolved and particulate organic matter such as feces and unconsumed feed from upper trophic species. The viability of sea cucumber integration into land-based aquaculture production facilities was investigated and discussed. The focus of the study was on the role of the sea cucumber as an ecosystem service. Consumption of nutrient-loaded waste is essential in reducing eutrophication and maintaining an ecological balance. I worked with Kauai Sea Farm’s (KSF) Dave Anderson (MAS MBC ’16), investigated and compiled the most recent findings in integrating sea cucumbers into their aquaculture farm at Nomilo Fishpond with a focus on sediment analysis and comparison of biomass of sea cucumbers used in this study.The primary goal of this preliminary study was to investigate the potential benefit of integrating sea cucumbers into existing aquaculture systems to clean up and reduce waste and at the same time improve environmental outcomes. This study highlights the viability of sea cucumber integration into land-based aquaculture farms, which addresses the value of waste reprocessing,and will significantly impact the future success of aquaculture farms.Please see media created in support of this project here: https://storymaps.arcgis.com/stories/13539350ebe648baa3b3ab1a1fb61e8a

Sex-determining mechanism is still ambiguous for sea cucumber Holothuria scabra which only manifests gonochorism in gonad. In this study, proteomic analysis was employed to delineate sex-related proteins and genes in gonads of H. scabra, subsequently validated through Quantitative real-time polymerase chain reaction (qRT-PCR). A total of 5,313 proteins were identified via proteome sequencing. Among these, 817 proteins exhibited expression in both the ovary and testis, with 445 proteins displaying up-regulation and 372 proteins showing down-regulation (ovary vs testis). Furthermore, 136 and 69 proteins were identified as ovary-specific and testis-specific Differentially Abundant Proteins (DAPs), respectively. And 9 DAP coding genes which play crucial role in ovary and testis were verified by qRT-PCR. Notably, 24 ovary-bias proteins enriched in ribosome pathway strongly indicated the crucial role of ribosome in ovary. This study serves to furnish novel evidence pertaining to sex differences in H. scabra. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) are involved in various physiological and pathological processes in both vertebrates and invertebrates. However, most studies on circRNAs have focused on their roles as endogenous competitive RNAs. Here, we report a novel function of circRNA derived from the Fibrinogen-like protein 1 gene (circ-FGL1) that inhibits coelomocyte apoptosis via competing with the deubiquitinase AjOTUB1 to bind AjMyc in Apostichopus japonicus during Vibrio splendidus infection. The results showed that circ-FGL1 is significantly downregulated in coelomocytes of V. splendidus-induced A. japonicus and negatively regulates coelomocyte apoptosis through the AjBax-AjCyt c pathway. Mechanistically, the deubiquitinase AjOTUB1 and circ-FGL1 could interact with the transcription factor protein AjMyc in the same region with circ-FGL1/AjMyc having greater affinity. Under normal conditions, high levels of circ-FGL1 bind directly to AjMyc, inhibiting the deubiquitylation of AjMyc by AjOTUB1 and leading to the degradation of AjMyc. After V. splendidus infection, AjMyc disassociates from the depressed expression of circ-FGL1, promoting its deubiquitylation by binding to the induced deubiquitinase AjOTUB1 to inhibit its degradation. AjMyc is then transferred to nucleus and promotes the transcription of AjCyt c and AjBax to induce coelomocyte apoptosis. The new finding will expand our present outstanding on the functional role of circRNAs and suggests new therapeutic targets for the treatment of echinoderms during bacterial invasion. Author summary: Apostichopus japonicus, a sea cucumber belonging to the phylum Echinodermata, represents an exceptional model for scientific research due to its unique evolutionary position between invertebrates and vertebrates. As a class rich in active substances with significant nutritional and medicinal value, sea cucumbers face threats from various pathogens, especially skin ulcer syndrome infected by Vibrio splendidus, which have caused substantial economic losses in A. japonicus aquaculture. A. japonicus counteract pathogen invasion through innate immunity and programmed cell death. Apoptosis, in particular, is the predominant mechanism for regulating cell death in echinoderms and has important implications for pathogen-induced immune homeostasis. Here, we identified circ-FGL1 as an antiapoptotic circRNA and found that circ-FGL1 interacts preferentially with the AjMyc protein, leading to the promotion of AjMyc degradation via ubiquitination under the normal conditions. After V. splendidus infection, induced AjOTUB1, a deubiquitinase, interacts with AjMyc at the same region as circ-FGL1 and facilitates the deubiquitination of AjMyc. AjMyc is then transferred to the nucleus, where it promotes the transcription of AjCyt c/AjBax, ultimately inducing coelomocyte apoptosis. Our study offers potential new therapeutic targets for treating in echinoderms during bacterial invasion. [ABSTRACT FROM AUTHOR]

Practical Application 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.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. [ABSTRACT FROM AUTHOR]

COVID-19 is a pandemic that has an impact on all aspects of life. This pandemic is caused by the SARS-CoV-2 virus, which has a fast pathogenesis cycle, so alternatives are needed, such as incredibly natural and marine ingredients that can be used as drug candidates. Holothuria atra is an animal candidate that has great potential. This study aims to describe the potential of H. atra as an antiviral candidate for COVID-19 through in silico analysis. The research began with extracts and GC-MS tests to identify the compound content in H. atra. Molecular docking analysis, Lipinski druglikeness, and toxicity predictions were carried out to determine the potential of the compound as an antiviral candidate for COVID-19 through inhibition of RNA-dependent RNA-polymerase protein (RdRp) and human Angiotensin Converting Enzym-2 (hACE2). The research results showed that there were five volatile compounds in the methanol extract of H. atra with one potential compound as a COVID-19 antiviral, namely Cyclohexanone, 2,6-bis((4-methoxyphenyl)methylene)-. Lipinski's druglikeness analysis and toxicity prediction provide support as a COVID-19 antiviral. Further research, such as in vitro and in vivo testing, can be carried out to give an overview of living cells and its activity as an antiviral for COVID-19. [ABSTRACT FROM AUTHOR]

The autolysis during live sea cucumber transportation is the main concern for the industry. This study aims to determine the effectiveness of ascorbic acid (AA) in reducing autolysis during the storage of live sea cucumbers. The live sea cucumbers were exposed for 5 days to seawater containing different concentrations of AA: 0, 5, 10, 15, 20, 25, 30, and 35 mg/L. Stored sea cucumber evaluation factors, including individual appearance, sensory score, histologic section, seawater ammonia nitrogen content, and free protein content, were tested. The reactive oxygen species (ROS) and malondialdehyde (MDA) accumulation, activity change of catalase (CAT), glutathione peroxidase (GSH-PX), and superoxide dismutase (SOD), and genes expression level change of succinate dehydrogenase (SDH), lactate dehydrogenase (LDH), SOD, and GSH-PX were compared after storage. The results showed that the AA addition of 25 mg/mL led to a good live sea cucumber condition. The sensory score for AA treatment reached 79.8% of the fresh group, and its stored seawater contained the lowest levels of ammonia nitrogen and soluble protein among all treatment groups. Although the villi in the 25 mg/L treatment group showed slight breakage, they maintained a relatively intact structure with clear cytoplasm and nuclei. The lowest ROS and MDA levels were observed in the intestine and respiratory tree of the 25 mg/L treatment group. The addition of 25 mg/L of AA maximized the activities of CAT, GSH-PX, and SOD. Moreover, the expression of SDH, LDH, SOD, and GSH-PX genes was upregulated 8.8-fold, 5.8-fold, 5.1-fold, and 16-fold compared with the fresh group, respectively. Live sea cucumbers can be transported with 25 mg/L AA treatment, which prevents autolysis-induced deterioration. [ABSTRACT FROM AUTHOR]

Target strength (TS) is an acoustic property of individual marine organisms and a critical factor in acoustic resource assessments. However, previous studies have primarily focused on measuring TS at narrowband, typical frequencies, which cannot meet the requirements of broadband acoustic technology research. Additionally, for marine fish, conducting in situ TS measurements is challenging due to environmental constraints. Rapidly freezing and preserving fish samples for transfer to the laboratory is a common method currently used. However, the impact of freezing preservation during transportation on the swimbladder morphology and TS of swimbladder-bearing fish remains unclear. This study investigated the differences in swimbladder morphology and TS of Chub mackerel (Scomber japonicus) before and after freezing. Then, we compared different TS measurement methods through ex situ TS measurements (45–90 kHz, 160–260 kHz) and the Kirchhoff-ray mode model (KRM) simulations (1–300 kHz) and studied the broadband scattering characteristics of Chub mackerel based on the KRM model. The results showed that the morphology of the swimbladder was reduced after freezing, with significant changes in swimbladder height and volume. However, the trends of TS were not consistent and the changes were small. The difference between the KRM model and ex situ measurements was −0.38 ± 1.84 dB, indicating good applicability of the KRM. Based on the KRM results, the TS exhibited significant directivity, with fluctuations gradually decreasing and stabilizing as frequency increased. In the broadband mode, the relationship between TS and body length (L) of Chub mackerel was TS = 20log(L) − 66.76 (30 > L/λ >10). This study could provide a reference for acoustic resource estimation and species identification of Chub mackerel in the Northwest Pacific Ocean. [ABSTRACT FROM AUTHOR]

Increasing consumer demand for healthier and tastier food options has spurred interest in identifying novel salty-enhancing peptides. This study aimed to extract novel salty-enhancing peptides from the collagen of sea cucumber. The model of the transmembrane channel-like 4 (TMC4) salt taste receptor was constructed by AlphaFold2 de novo modeling, and the interaction between peptides and salt taste receptor was studied by molecular dynamics (MD) simulation. The results revealed that 99.4% of amino acid residues in the Ramachandran Plot of the TMC4 model resided within the allowed region, thereby substantiating the rationality of the model. The molecular docking results indicated that Gln 279, Glu 92, and Lys 278 may be the key amino acids binding to the TMC4 receptor. The CSRH and KDINNRF showed significant enhancement in saltiness compared to the control group (2.62 ± 0.04), with saltiness values of 3.01 ± 0.00 and 2.86 ± 0.04, respectively. In addition, MD simulation results showed that TMC4 saltiness receptors formed stable RMSD and Rg with salty-enhancing peptides at 0–25 ns simulation time. This study verified that CSRH and KDINNRF are effective salty-enhancing peptides, and also provided a theoretical basis for the discovery of new salty-enhancing peptide resources in marine organisms. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to determine the reproductive cycle and spawning frequency of the sea cucumber Holothuria tubulosa in the northeastern Aegean Sea. Methods: The study covered a period of 12 months, beginning in October 2018 and concluding in September 2019. During this period, sea cucumber samples were collected monthly. Macroscopic and histological examinations of gonadal tubules were conducted to provide credible information for fishery management and aquaculture. Result: The sex ratio of the sampled population was 1:1.3, with 95 males and 130 females. The drained body weights at 50% maturity were 70.90 g for females and 70.80 g for males. The total length at 50% maturity was estimated at 18.58 cm for females and 18.05 cm for males. Gonad maturation was initiated in March and progressed to spawning stages between July and August. From September to February, the gonads were in postspawning and recovery stages. A strong linear correlation was determined between the gonad index and the seawater temperature in the area. Conclusion: The information provided is expected to improve stock management, enforce fishery regulations, and support controlled breeding programs. These measures aim to preserve the natural populations of Holothuria tubulosa and guarantee the long‐term viability of the species in the wild. Impact statementThe Holothuria tubulosa is the most abundant commercial sea cucumber species found in the Mediterranean Sea, particularly in the Aegean Sea. This species plays an important ecological role in nutrient regeneration and surface sediment mineralization in the benthic zone; however, there is significant catch pressure on natural stocks. This study revealed the reproductive cycle of this Mediterranean Sea cucumber species, offering crucial data for sustainable fisheries and aquaculture. By understanding their breeding patterns, we can better manage wild populations and develop controlled breeding programs, ensuring the long‐term survival of the species and supporting healthy marine ecosystems. [ABSTRACT FROM AUTHOR]

Sea cucumbers are well demarcated for their valuable role in the food, pharmaceutical, nutraceutical, and cosmeceutical sectors. The demand for well-processed dried sea cucumber retaining quality is prioritized by local markets and industries. There are several techniques for the pre-processing of fresh sea cucumbers, including traditional and modern methods, such as salting, boiling, high-pressure processing, high-pressure steaming, and vacuum cooking, among others, in order to inactivate enzymes and microbial attacks. Further, pre-treated sea cucumbers require post-processing before human consumption, transportation, or industry uses such as hot air, freeze, cabinet, sun, or smoke drying. However, despite the ease, traditional processing is associated with several challenges hampering the quality of processed products. For instance, due to high temperatures in boiling and drying, there is a higher chance of disrupting valuable nutrients, resulting in low-quality products. Therefore, the integration of traditional and modern methods is a crucial approach to optimizing sea cucumber processing to obtain valuable products with high nutritional values and retain bioactive compounds. The value of dried sea cucumbers relies not only on species and nutritional value but also on the processing methods in terms of retaining sensory attributes, including colour, appearance, texture, taste, and odour. Therefore, this review, for the first time, provides insight into different pre- and post-treatments, their perspective, challenges, and how these methods can be optimized for industry use to obtain better-quality products and achieve economic gains from sea cucumber. [ABSTRACT FROM AUTHOR]

Background: The holothurians, commonly known as sea cucumbers, are marine organisms that possess significant dietary, nutritional, and medicinal value. However, the National Center for Biotechnology Information (NCBI) currently possesses only approximately 70 complete mitochondrial genome datasets of Holothurioidea, which poses limitations on conducting comprehensive research on their genetic resources and evolutionary patterns. In this study, a novel species of sea cucumber belonging to the genus Benthodytes, was discovered in the western Pacific Ocean. The genomic DNA of the novel sea cucumber was extracted, sequenced, assembled and subjected to thorough analysis. Results: The mtDNA of Benthodytes sp. Gxx-2023 (GenBank No. OR992091) exhibits a circular structure spanning 17,386 bp, comprising of 13 protein-coding genes (PCGs), 24 non-coding RNAs (2 rRNA genes and 22 tRNA genes), along with two putative control regions measuring 882 bp and 1153 bp, respectively. It exhibits a high AT% content and negative AT-skew, which distinguishing it from the majority of sea cucumbers in terms of environmental adaptability evolution. The mitochondrial gene homology between Gxx-2023 and other sea cucumbers is significantly low, with less than 91% similarity to Benthodytes marianensis, which exhibits the highest level of homology. Additionally, its homology with other sea cucumbers is below 80%. The mitogenome of this species exhibits a unique pattern in terms of start and stop codons, featuring only two types of start codons (ATG and ATT) and three types of stop codons including the incomplete T. Notably, the abundance of AT in the Second position of the codons surpasses that of the First and Third position. The gene arrangement of PCGs exhibits a relatively conserved pattern, while there exists substantial variability in tRNA. Evolutionary analysis revealed that it formed a distinct cluster with B. marianensis and exhibited relatively distant phylogenetic relationships with other sea cucumbers. Conclusions: These findings contribute to the taxonomic diversity of sea cucumbers in the Elasipodida order, thereby holding significant implications for the conservation of biological genetic resources, evolutionary advancements, and the exploration of novel sea cucumber resources. [ABSTRACT FROM AUTHOR]

Sea cucumber has emerged as a crucial economic species in aquaculture in China because of its remarkable nutritional and medicinal value. However, wild sea cucumber populations have experienced a decline due to overfishing and environmental factors, underscoring the urgent need for genetic resource conservation and biotechnology innovation within the sea cucumber aquaculture and breeding industry. The development of the sea cucumber industry is still impeded by challenges and difficulties. Nevertheless, significant progress has been made through the utilization of molecular markers, which have effectively addressed a number of fisheries and aquaculture issues. In recent years, diverse types of molecular markers including mitochondrial DNA, microsatellites, and SNP markers have been developed and extensively applied in various aspects of sea cucumber research. These markers play vital roles in genetic sex identification, germplasm resource evaluation, population structure assessment, as well as marker-assisted breeding in marine ranching and sea cucumber aquaculture and breeding industry. This review provides an overview of the fundamental principles, functions, and characteristics associated with various markers employed across various sea cucumber species while also discussing their applications within different aspects of the sea cucumber fisheries, aquaculture, and breeding industry. [ABSTRACT FROM AUTHOR]

Monitoring methods for beta-lactam (β-lactam) antibiotics, especially for ampicillin (AMP), with simple operation and sensitivity for realtime applications are highly required. To address this need, antioxidant carbon dots (E-CDs) with excellent fluorescence properties were synthesized using citric acid and ethylenediamine as raw materials. With a quantum yield of 81.97%, E-CDs exhibited a specific and sensitive response to ˙OH. The quenched fluorescence of E-CDs by the formed ˙OH could be restored through a competition reaction with AMP. Leveraging the signal-quenching strategy of E-CDs, H2O2, and Fe2+, a fluorescence signal-on strategy was developed using AMP as the fluorescence recovery agent for the sensitive detection of AMP. The mechanism of the quenching of E-CDs by ˙OH was attributed to the damaging effect of ˙OH on E-CDs. Under optimal conditions, the detection limit of this method for AMP was determined to be 0.38 μg mL−1. This method was successful in drug quality control and the spiked detection of AMP in lake water, milk, and sea cucumber, presenting a viable option for convenient and rapid antibiotic monitoring methods. [ABSTRACT FROM AUTHOR]

Simple Summary: Starfish are the natural enemies of shellfish. In many areas, especially in Qingdao, China, shellfish aquaculture has been adversely affected by starfish predation for many years, resulting in serious economic losses. To facilitate strategies for the protection of shellfish from starfish, this review analyzes the reasons for the proliferation of starfish and proposes governance suggestions for the control and utilization of starfish. Starfish are keystone species as predators in benthic ecosystems, but when population outbreaks occur, this can have devastating consequences ecologically. Furthermore, starfish outbreaks and invasions can have adverse impact economically by impacting shellfish aquaculture. For example, an infestation of starfish in Qingdao led to a 50% reduction in sea cucumber production and an 80% reduction in scallop production, resulting in an economic loss of approximately RMB 100 million to oyster and other shellfish industries. Addressing the imperative need to proactively mitigate starfish invasions requires comprehensive research on their behavior and the underlying mechanisms of outbreaks. This review scrutinizes the historical patterns of outbreaks among diverse starfish species across various regions, delineates the factors contributing to the proliferation of Asterias amurensis in Chinese waters, articulates preventive and remedial strategies, and outlines the potential for the sustainable utilization of starfish. [ABSTRACT FROM AUTHOR]

Madagascar's seagrass meadows are among the least-studied ecosystems in the western Indian Ocean region. To facilitate sustainable management, understanding the traditional uses of seagrass areas in relation to current management policies is necessary. This study assessed the uses of, and policies relevant to, seagrass ecosystems off southwestern Madagascar. We interviewed 131 community members in five coastal villages around the Bay of Ranobe in Toliara Province. Answers to the survey revealed a good level of awareness of seagrass, though 55% of respondents perceived the status of the seagrass areas as deteriorating. Opinions varied on the source or degree of threats to seagrass, but 74.8% of respondents suggested destructive fishing methods or other factors, including natural phenomena and animal grazing. The responses highlight that seagrass meadows serve as areas important for fishing, seaweed cultivation or sea cucumber farming, and the passage of boat/pirogue transportation. There are currently no tangible policies that directly protect or manage the seagrass areas regarding these activities, although some national regulations and local management initiatives are indirectly relevant, notably no-take zones and the local-level codes known as Dina. Development and implementation of a national management plan for seagrass ecosystems is a key gap. This demands the collection of scientific data to support decision-making to ensure long-term provision of the services provided by seagrass meadows. The involvement of coastal communities in the management of seagrass ecosystems will be necessary for the success of any new policies. [ABSTRACT FROM AUTHOR]

The Sox gene family, a collection of transcription factors widely distributed throughout the animal kingdom, plays a crucial role in numerous developmental processes. Echinoderms occupy a pivotal position in many research fields, such as neuroscience, sex determination and differentiation, and embryonic development. However, to date, no comprehensive study has been conducted to characterize and analyze Sox genes in echinoderms. In the present study, the evolution and expression of Sox family genes across 11 echinoderms were analyzed using bioinformatics methods. The results revealed a total of 70 Sox genes, with counts ranging from 5 to 8 across different echinoderms. Phylogenetic analysis revealed that the identified Sox genes could be categorized into seven distinct classes: the SoxB1 class, SoxB2 class, SoxC class, SoxD class, SoxE class, SoxF class and SoxH class. Notably, the SoxB1, SoxB2, and SoxF genes were ubiquitously present in all the echinoderms studied, which suggests that these genes may be conserved in echinoderms. The spatiotemporal expression patterns observed for Sox genes in the three echinoderms indicated that various Sox members perform distinct functional roles. Notably, SoxB1 is likely involved in echinoderm ovary development, while SoxH may play a crucial role in testis development in starfish and sea cucumber. In general, the present investigation provides a molecular foundation for exploring the Sox gene in echinoderms, providing a valuable resource for future phylogenetic and genomic studies. [ABSTRACT FROM AUTHOR]

Marine organisms are vast sources of bioactive components, with holothorians, or sea cucumbers being one of these sources. Therefore, sea cucumber specimens were examined as a promising source of natural substances that can be used as antibacterial, antifungal, anti-inflammatory, antioxidant, antiviral, and antitumor agents. Holothuria papillifera was collected from Zaafarana, Ras Ghareb, and Altur stations and employed as a biological weapon against some pathogens. H. papillifera extracts showed high activity as antibacterial extracts against Staph. aureus and Enterococcus faecalis (Gram+ve), Escherichia coli, Salmonella typhi, and Klebsiella pneumoniae (Gram-ve). It also exhibited positive antifungal efficacy against Candida albicans and revealed moderate activity against liver cancer cells and a weak activity against breast cancer cells. Alternatively, H. papillifera crude extract has weak antiviral activity against CoxB4 and very weak antiviral efficacy against HAV (hepatitis A virus). Moreover, our results proved that H. papillifera extract had anti-inflammatory effects and exhibited antioxidant power. In conclusion, H. papillifera has broad antimicrobial activity against many pathogens, as well as antioxidant, antitumor, anti-inflammatory, among others. It is recommended to explain and characterize the composition of the bioactive compounds of H. papillifera to be included in the pharmaceutical industry. [ABSTRACT FROM AUTHOR]

Sea cucumbers, members of the echinoderm class Holothuroidea, are marine invertebrates with ecological significance and substantial commercial value. With approximately 1700 species, these organisms contribute to marine ecosystems through nutrient cycling and face various threats, including overfishing and habitat loss. Despite their importance, they are extensively exploited for diverse applications, from seafood to pharmaceuticals. This study investigates sea cucumbers' nutritional profile and bioactive elements, emphasizing their role as sources of essential compounds with potential health benefits. The demand for sea cucumbers, especially in dried form, is significant, prompting exploration into various drying techniques. Examining the global trade in sea cucumbers highlights their economic importance and the conservation challenges they face. Conservation efforts, such as awareness campaigns and international collaboration, are evaluated as essential steps in combating illicit trade and promoting the sustainable stewardship of sea cucumber populations. Practical Application: Around 1700 species of sea cucumbers were identified as vital ecological scavengers in the Holothuroidea class. High commercial value due to their health benefits, particularly their demonstrated inhibitory effect against various types of cancer. "Beche‐de‐mer" holds a 90% market share and is regarded as a luxury food item in Southeast Asian countries. Due to overexploitation, the species is classified as Schedule I under the Wildlife Protection Act (WPA) in India, prompting the implementation of a blanket ban on their harvesting to ensure its conservation. [ABSTRACT FROM AUTHOR]

We aimed to explore the anti-obesity mechanism from the microbiome, metabolome, and transcriptome viewpoints, focusing on the sulfated polysaccharides found in the cooking liquid of Apostichopus japonicus (CLSPAJ) to explore the potential mediators of the anti-obesity effects in mice fed a high-fat diet (HFD). The mice treated with CLSPAJ showed a decrease in obesity and blood lipid levels. Gut microbiome dysbiosis caused by the HFD was reversed after CLSPAJ supplementation, along with increased levels of indole-3-ethanol, N-2-succinyl-L-glutamic acid 5-semialdehyde, and urocanic acid. These increases were positively related to the increased Akkermansia, Lactobacillus, Roseburia, and Phascolarctobacterium. Transcriptome analysis showed that B cell receptor signaling and cytochrome P450 xenobiotic metabolism were the main contributors to the improvement in obesity. Metabolome–transcriptome analysis revealed that CLSPAJ reversal of obesity was mainly due to amino acid metabolism. These findings suggest that CLSPAJ could be a valuable prebiotic preparation for preventing obesity-related diseases. [ABSTRACT FROM AUTHOR]

A 70-day feeding experiment was performed to investigate the effects of dietary vitamin E at different addition levels (0, 100, 200, and 400 mg/kg) on the growth, collagen content, antioxidant capacity, and expressions of genes related to the transforming growth factor beta (TGF-β)/Sma- and Mad-related protein (SMAD) signaling pathway in sea cucumbers (Apostichopus japonicus). The results showed that the A. japonicus in the group with 200 mg/kg vitamin E exhibited significantly higher growth rates, hydroxyproline (Hyp) and type III collagen contents, and superoxide dismutase (SOD) activity, as well as the upregulation of genes related to Tenascin, SMAD1, and TGF-β. Additionally, the A. japonicus in the group with 100 mg/kg vitamin E exhibited significantly higher body-wall indexes, denser collagen arrangements, improved texture quality, higher activities of glutathione peroxidase (GSH-Px) and peroxidase (POD), as well as the upregulation of genes related to collagen type I alpha 2 chain (COL1A2), collagen type III alpha 1 chain (COL3A1), and Sp-Smad2/3 (SMAD2/3). In contrast, the A. japonicus in the group with 400 mg/kg vitamin E showed a decrease in the growth rates, reduced Hyp contents, increased type I collagen contents, collagen fiber aggregation and a harder texture, along with the downregulation of genes related to the TGF-β/SMAD signaling pathway. Furthermore, the A. japonicus in the group with 400 mg/kg exhibited oxidative stress, reflected by the lower activities of SOD, GSH-Px, and POD. These results indicated that A. japonicus fed diets with the addition of 100–200 mg/kg vitamin E had improved collagen retention and texture quality by increasing the activities of antioxidant enzymes and the expressions of genes in the TGF-β/SMAD signaling pathway. However, the excessive addition of vitamin E (400 mg/kg) induced oxidative stress, which could increase the collagen degradation and fibrosis and pose a threat to the growth and texture quality of A. japonicus. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive checklist of sea cucumber species found in Biluhu Timur waters, Tomini Bay, Gorontalo, Indonesia, across the new moon and full moon lunar phases. The survey identified eight species across five genera, including Actinopyga miliaris, A. mauritiana, Holothuria scabra, and H. leucospilota, noting significant distribution patterns influenced by lunar cycles and different biomes at three stations. Actinopyga miliaris and A. mauritiana, both classified as Vulnerable, were more active in the seagrass biome of Station I during the full moon. H. leucospilota, classified as Least Concern, was highly prevalent in the sandy substrate biome of Station II during the new moon, indicating a strong ecological association with that habitat. Stichopus horrens, classified as Data Deficient, showed notable activity in the coral reef biome of Station III. Environmental parameters such as water temperature, salinity, and pH were measured at each station to understand the conditions influencing these species. This study highlights the importance of lunar phases, biomes, and environmental variables on sea cucumber distribution. The findings underscore the need for conservation efforts that consider these factors to protect species vulnerable to overfishing and habitat degradation. Further research should include genetic analysis and expanded temporal and spatial scales to develop effective conservation strategies and sustainable management practices

As a kind of green and high quality feed, fermented feed has the activity of promoting growth and improving immunity in aquaculture. The aim of this study was to develop a new liquid fermented feed for the culture of sea cucumber Apostichopus japonicus and evaluate its nutritional value and function. After the commercial feed of the sea cucumber was fermented by Corynebacterium glutamicum, the contents of crude protein, free amino acids, palmitoleic acid, linoleic acid, arachidonic acid, and the total content of polyunsaturated fatty acids were significantly increased. By feeding the fermented food, the weight gain rate, special growth rate and feed conversion rate of the sea cucumber were significantly increased, and the mortality rate was significantly reduced in the challenge test. The cellulase activity in the gut of the sea cucumber fed with the fermented feed was significantly increased, while the activities of alkaline phosphatase, acid phosphatase, total nitric oxide synthase, catalase, and lysozyme in the coelomic fluid were significantly increased. The fermented feed changed the gut microbiota of the sea cucumber and significantly reduced the relative abundance of Vibrio, which was the main pathogen causing skin ulcer syndrome. Transcriptome analysis revealed 4492 differentially expressed genes that can be enriched in biological processes such as immune system processes and immune responses, and affect the growth performance and immune regulation of the sea cucumber through metabolic pathways such as ribosomal biogenesis. Further gene expression analysis showed that the upregulation of genes such as NFκBI, TLR, TLR3, TRAF6, MyD88, and p38 activated the TLR signaling pathway and enhances the immune response of the sea cucumber. Therefore, C. glutamicum fermented feed can promote the growth of the sea cucumber, enhance non-specific immunity, and resist pathogen infection, making it a highly promising feed for application. [ABSTRACT FROM AUTHOR]

Background and objectives: The high incidence and mortality rate of breast cancer indicates that managing this disease is still problematic. A number of studies have shown that sea cucumbers, marine invertebrates, contain anticancer compounds. This study aimed to determine the effects of Holothuria scabra (sea cucumber) methanol extract on histopathological features, interleukin-6 (IL-6) concentration, and nuclear factor kappa B (NF-κB) expression in the breast cancer mice model. Methods: The body of H. scabra without internal organs was extracted with methanol. Thirty female Mus musculus C57BL6 mice were randomly divided into a control group, a breast cancer mice model group, and three treatment groups, which were breast cancer mice models administered with three various doses H. scabra methanol extract (0.33 (T1); 0.66 (T2); and 0.99 g/Kg BW (T3)) for 12 weeks. The breast cancer mice model was treated with a high-fat diet and 1 mg/kg BW 7, 12-dimethylbenz[a]anthracene subcutaneous injection into one of the breasts. Examination of IL-6 concentration was conducted by ELISA and NF-κB gene expression by qRT-PCR. Results: The results showed an improvement in histopathological features as revealed by the lower Nottingham scores in the T2 (5.17±0.75) and T3 groups (3.00±0.89) compared to positive control group 7.00±1.26 (p

The present study explores rare but taxonomically and geographically widespread cases of anterior body axial bifurcation in adult sea cucumbers (Echinodermata: Holothuroidea). One individual of Holothuria (Halodeima) grisea, a common intertidal species along the Atlantic coast of Brazil, was studied externally and internally. Individuals of Apostichopus californicus from the northeastern Pacific coast of Washington (USA), H. (Mertensiothuria) leucospilota in the Indian Ocean off La Réunion, H. (Panningothuria) forskali from the Atlantic coast of Spain, and Parastichopus tremulus from the northeastern Atlantic off Norway were also reported to display similar anterior body axial bifurcation. In each of these species, the anterior body presented two mouths with their respective crown of tentacles. In vivo observations of H. (Halodeima) grisea showed that the two tentacle crowns and mouths were independently functional. Micro‐computed tomography (μCT) revealed that the anterior region of the body (up to the pharynx) was duplicated. Internally, two aquapharyngeal bulbs were found, each with their own calcareous ring (one with two plates missing), madreporite, and Polian vesicles. The body presented a normal set of five longitudinal muscle bands, some of which bifurcated orally to support more than one calcareous ring plate. This is the first report of such abnormalities in Holothuroidea and hypotheses that may explain such phenomenon are discussed. [ABSTRACT FROM AUTHOR]

The sandfish Holothuria (Metriatyla) scabra, is a high-value tropical sea cucumber harvested from wild stocks for over four centuries in multi-species fisheries across its Indo-Pacific distribution, for the global bê che-de-mer (BDM) trade. Within Southeast Asia, the Philippines is an important centre of the BDM trade, however overharvesting and largely open fishery management have resulted in declining catch volumes. Sandfish mariculture has been developed to supplement BDM supply and assist restocking efforts; however, it is heavily reliant on wild populations for broodstock supply. Consequently, to inform fishery, mariculture, germplasm and translocation management policies for both wild and captive resources, a high-resolution genomic audit of 16 wild sandfish populations was conducted, employing a proven genotyping-bysequencing approach for this species (DArTseq). Genomic data (8,266 selectively-neutral and 117 putatively-adaptive SNPs) were used to assess finescale genetic structure, diversity, relatedness, population connectivity and local adaptation at both broad (biogeographic region) and local (within-biogeographic region) scales. An independent hydrodynamic particle dispersal model was also used to assess population connectivity. The overall pattern of population differentiation at the country level for H. scabra in the Philippines is complex, with nine genetic stocks and respective management units delineated across 5 biogeographic regions: (1) Celebes Sea, (2) North and (3) South Philippine Seas, (4) South China and Internal Seas and (5) Sulu Sea. Genetic connectivity is highest within proximate marine biogeographic regions (mean Fst=0.016), with greater separation evident between geographically distant sites (Fst range=0.041-0.045). Signatures of local adaptation were detected among six biogeographic regions, with genetic bottlenecks at 5 sites, particularly within historically heavilyexploited locations in the western and central Philippines. Genetic structure is influenced by geographic distance, larval dispersal capacity, species-specific larval development and settlement attributes, variable ocean current-mediated gene flow, source and sink location geography and habitat heterogeneity across the archipelago. Data reported here will inform accurate and sustainable fishery regulation, conservation of genetic diversity, direct broodstock sourcing for mariculture and guide restocking interventions across the Philippines. [ABSTRACT FROM AUTHOR]

Recently, phosphorylation has been applied to peptides to enhance their physiological activity, taking advantage of its modification benefits and the extensive study of functional peptides. In this study, water-soluble peptides (WSPs) of sea cucumber ovum were phosphorylated in order to improve the latter's calcium binding capacity and calcium absorption. Enzymatic hydrolysis methods were screened via ultraviolet-visible absorption spectroscopy (UV–Vis), the fluorescence spectrum, and calcium chelating ability. Phosphorylated water-soluble peptides (P-WSPs) were characterized via high-performance liquid chromatography, the circular dichroism spectrum, Fourier transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, surface hydrophobicity, and fluorescence spectroscopy. The phosphorus content, calcium chelation rate and absorption rate were investigated. The results demonstrated that phosphorylation enhanced the calcium chelating capacity of WSPs, with the highest capacity reaching 0.96 mmol/L. Phosphate ions caused esterification events, and the carboxyl, amino, and phosphate groups of WSPs and P-WSPs interacted with calcium ions to form these bonds. Calcium-chelated phosphorylated water-soluble peptides (P-WSPs-Ca) demonstrated outstanding stability (calcium retention rates > 80%) in gastrointestinal processes. Our study indicates that these chelates have significant potential to develop into calcium supplements with superior efficacy, bioactivity, and stability. [ABSTRACT FROM AUTHOR]

To explore animal diversity, new experimentally tractable organisms must be established. Echinoderms include five groups of marine animals that have been used as developmental models for over a century thanks to their low costs, high fecundity, optically clear larvae and genetic tractability. An additional advantage of echinoderms is that their larval forms display diverse morphologies. This rich diversity enables comparative studies to investigate the evolutionary relationships among cell types, tissues, and organs. However, reproducible protocols to obtain gametes, detailed information on embryogenesis, and genomic tools have been optimized only for selected species of sea urchins and sea stars. To address this gap, we established the abundant Mediterranean sea cucumber Holothuria tubulosa as a new experimental system. Here we describe a method to reliably obtain gametes and make embryonic cultures multiple times from the same animal and characterize unique larval tissues combining immunohistochemistry and high-resolution microscopy. This work represents a step forward in our understanding of holothurian development and establishes H. tubulosa as an emerging experimental system for evo-devo and other biological disciplines. [ABSTRACT FROM AUTHOR]

A unifying feature of echinoderm larvae is the development of a left anterior coelom, which consists of an undivided left axocoel and hydrocoel. Although the axocoel is a key deuterostome trait, the presence of this coelom in holothurians has been the subject of debate. Here, we focus on the development of the coelom in a basal holothuroid, the apodid Chiridota gigas (F. Chiridotidae). The dorsal pore and dorsal duct develop first, just after gastrulation, followed by expansion into an axohydrocoel in the auricularia. The left somatocoel was first evident adjacent to the stomach ~30 days post‐fertilization. The axohydrocoel differentiated into two distinct parts: the hydrocoel adjacent to the stomach, and a thin‐walled axocoel that was mid‐dorsal between the hydrocoel and the dorsal pore. This left axocoel extended to both the anterior and posterior but did not cross the larval midline. Out‐folding of the hydrocoel to form the primary tentacles was first observed at 58 days. Transition to a doliolaria with four‐rings was rapid (24 hr) and similar to the transition in other holothurians, with the hydrocoel encircling the esophagus. This transition involved a posterior shift of elements of the auricularia ciliary band and associated nervous system. The ciliary band of the auricularia was rearranged to form transverse bands of the doliolaria larva, and at the same time, the serotonergic cells and fibers that had been at the anterior end moved with the portions of the ciliary band with which they were associated. These serotonergic cells and fibers were still present in the pentactula. The first pentactula was observed at 66 days. Coelom development in C. gigas showed two differences from that in other holothurians, including the development of the left axocoel and the extension of the anterior coelom into the preoral lobe. Description of the full larval development in C. gigas also revealed highly variable morphology in the late auricularia stage, which may aid in identifying apodid holothurians from plankton samples. [ABSTRACT FROM AUTHOR]

The sea cucumber Holothuria inornata is a species whose populations are at risk. This study aims to investigate its reproduction, embryonic and larval development, and the settlement of H. inornata under an algae-based diet. Twenty breeders were utilized, which underwent a 1.5-h desiccation followed by a thermal shock (27 to 32 °C). Embryonic development stage was recorded, and from the auricularia larval stage, three treatments were evaluated: A: Chaetoceros muelleri and Isochrysis galbana (1:1 ratio); B: C. muelleri, I. galbana, Tetraselmis suecica, and Pavlova lutheri (1:1:1:1 ratio); and C: Chaetoceros muelleri, I. galbana, T. suecica, P. lutheri, Navicula sp. (LPU-6) (1:1:1:1:1 ratio), with a larval density of 100 larvae L−1 in triplicate. The embryonic development in H. inornata lasts for 3 days, five larval stages were recorded: (1) Auricularia (days 3–8, 300 to 520 μm), (2) late auricularia (days 8–11, 520 to 670 μm), (3) doliolaria (days 11–13, 460 to 550 μm), (4) late doliolaria (days 13–16, 400 to 440 μm), and (5) pentacula (days 15–19, 650 to 900 μm). The post-settlement survival rate was 0% under treatment A, 2.38 ± 0.16% under treatment B, and 3.79 ± 0.41% under treatment C. Based on these findings, we concluded that H. inornata specie spawn through a combined desiccation-thermal shock process with a larval period of up to 19 days, and subsequently produce juvenile individuals in captivity with a varied microalgae diet. [ABSTRACT FROM AUTHOR]

Simple Summary: Holothuria tubulosa is a widespread edible Mediterranean species of sea cucumber. In an attempt to identify new compounds that might exert an anti-diabetic effect, the aqueous extract from the coelomic fluid (CFE) of H. tubulosa was prepared and tested for its extracellular glucose-lowering activity on hepatic cells in culture. Here, we have identified some cellular and molecular aspects of the beneficial effect of the CFE that stimulates glucose consumption/uptake and glycogen storage inducing the increased synthesis and translocation to the cell surface of the glucose transporters GLUT-2 and -4. These marine-derived natural material is worth further exploration aimed at developing novel alternative agents against diabetes mellitus and beneficial supplements for the formulation of functional food. The cell-free aqueous extract from the coelomic fluid of Holothuria tubulosa was prepared and examined for its glucose-lowering effect on HepG2 cells in vitro. In particular, employing a combination of cytochemical, flow cytometric, PCR, and protein blot techniques, we evaluated its role on glucose internalization and storage and on the upregulation and surface translocation of the two glucose transporters GLUT-2 and -4. The changes in expression, synthesis, and/or activation of the GLUT2-related transcription factor hepatocyte nuclear factor-1 alpha (HNF1α) and the GLUT-4-translocation regulatory factors insulin receptor substrate-1 (IRS-1) and AKT were also studied. Our results showed the improved glucose response by HepG2 cells, leading to an evident increase in glucose consumption/uptake and glycogen storage upon exposure. Moreover, the extract induced molecular reprogramming involving the upregulation of (i) IRS1 gene expression, (ii) the transcription and translation levels of HNF1α, AKT, and GLUT-4, (iii) the phosphorylation level of AKT, (iv) the synthesis of GLUT-2 protein, and (v) the translocation of GLUT-2 and -4 transporters onto the plasma membrane. Cumulatively, our results suggest that the coelomic fluid extract from H. tubulosa can be taken into consideration for the development of novel treatment agents against diabetes mellitus. [ABSTRACT FROM AUTHOR]

Enzymatic hydrolysis is a green approach for nutrient bioconversion of sea cucumber body wall to recover sulfated polysaccharides. However, formation of high level of advanced glycation end products (AGEs) can potentially negate health benefits of the functional food. In this study, UV-assisted autolysis was employed to optimize nutrient bioconversion of Stichopus horrens body wall using extreme UV dosage (324,000-648,000 J/m2), different autolysis temperatures (40–60 °C) and time (3–5 h). Parallel biochemical changes indicate that UV irradiation promoted the activation of endogenous enzymes, leading to the proteolysis of the body wall and the subsequent dissolution of sulfated polysaccharides. Changes in the amide band I region of the Fourier-transform infrared (FTIR) spectra of autolyzed body wall residue reflected the loss of α-helix secondary structures of collagen which exacerbated at autolysis temperatures beyond 50 °C. The maximum yield of sulfated polysaccharides and antioxidant activities were obtained at the condition (486,000 J/m2 of UV dosage, 60 ℃, and 4 h of autolysis) by the optimization using the central composite design. The nutritional composition and safety aspect of the autolysate was compared with hydrolysate from enzymatic hydrolysis and hot water extract. Quantification of 5-hydroxymethylfurfural (HMF) showed that UV-assisted autolysis could mitigate HMF formation (0.12 mg/kg) by 97.6% compared to enzymatic hydrolysis (5.13 mg/kg) and 42.9% compared to hot water extraction (0.21 mg/kg). The UV-assisted autolysis with metal ion further enhanced the extraction process of sulfated polysaccharides from sea cucumber body wall and reduction of the processing contaminants. Thus, UV-assisted autolysis offers a safer alternative for the nutrient bioconversion of sea cucumber body wall, particularly for the development of functional foods. [ABSTRACT FROM AUTHOR]

Artificial reefs have been advocated and implemented as management tools for aquaculture, species conservation and habitat replacement. However, the shelter capacity of artificial reefs and its influencing factors are still not well understood. In this study, we identified factors that may limit the shelter capacity of artificial reefs for sea cucumber (Apostichopus japonicas) with a laboratory experiment. We investigated how water flow and food availability affect the shelter capacity and conducted shelter utilization experiments to determine whether sea cucumber sheltering behavior was density dependent. The results revealed that shelter capacity of artificial reefs in high velocity is significantly higher than that of artificial reefs in low velocity or no velocity. The artificial reefs that were provided food had significantly higher shelter capacity than those that did not have food. The densities did not affect the sheltering capacity of artificial reefs in the laboratory experiment. There was a logarithmic relationship between the shelter capacity and shelter availability assessed by the exposed surface area of the artificial reefs. In conclusion, abundant food resources and high water flow may have a positive effect on the shelter capacity of artificial reefs. [ABSTRACT FROM AUTHOR]

Background: The family Synallactidae comprises mostly deep-sea forms and is the least-studied large taxon amongst deep-sea cucumbers. They are part of the abyssal megafauna and play an important role in modifying the sediment landscape and structuring the communities that live within it. The family embraces the genus Synallactes, which contains approximately twenty-five species from the Pacific, Atlantic (six species), Indian (seven species) and Antarctic Oceans (one species). New information: Synallactes mcdanieli sp. nov. is described from the Northeast Pacific, Knight Inlet, British Columbia, Canada to Kodiak Island, Gulf of Alaska, USA, at depths from 21 to 438 m. This new species is unique amongst the species of the genus Synallactes because of the number and arrangement of dorsal papillae, number of Polian vesicles, together with the entire ossicle arrangement. In addition, this species has the shallowest bathymetric distribution ever recorded for this genus. [ABSTRACT FROM AUTHOR]

Holothuria atra (Echinodermata: Holothuroidea) is a type of invertebrate animal that lives on the bottom of the rocky coast and has the potential as a nutritious food raw material for humans and pharmaceutical raw materials. The study aims to determine the microplastic types, microplastic functional groups and simulate the distribution pattern of ingested microplastics in the digestive system of H. atra based on hydrodynamic activity. Microplastic separation was conducted by extraction using the flotation method based on predetermined criteria. Functional group test of microplastic polymers ingested in intestines of sea cucumbers using FT‐IR (Frontier Transform Infrared‐Spectroscopy) Analysis. Hydrodynamic modeling analysis used secondary data: bathymetric, currents, wind direction, and tidal prediction data. The results of sampling of H. atra sea cucumbers at four observation locations, where ten individual sea cucumbers were taken from each location, showed that microplastic waste exposed in the intestines of sea cucumbers obtained an average value of 14,166 individuals‐1, with a particle length range of 0.214–3.978 mm. The highest abundance was from the type of fiber, followed by fragments, pellets, and films. FTIR test results indicate the presence of several functional microplastic groups that are digested in the intestine, including polyamide (PA)/nylon‐6, polyethylene (PE), polypropylene (PP), and polystyrene (PS). The movement of currents carrying microplastic waste particles is dominated to the west and south of Karimunjawa Island, potentially endangering the habitats of sea cucumbers and other animals in the waters of the surrounding small islands. It is recommended that stakeholders establish plastic waste protocols, waste facilities and treatment, and strict supervision of tourists entering the Karimunjawa tourism environment. [ABSTRACT FROM AUTHOR]

Due to the dramatic reduction of sea cucumber Isostichopus badionotus populations in the Yucatan Peninsula by overfishing and poaching, aquaculture has been encouraged as an alternative to commercial catching and restoring wild populations. However, the scarcity of broodstock, the emergence of a new disease in the auricularia larvae stage, and the development of skin ulceration syndrome (SUS) in the culture have limited aquaculture development. This study presents the changes in the intestine and skin microbiota observed in early and advanced stages of SUS disease in cultured juvenile I. badionotus obtained during an outbreak in experimental culture through 16S rRNA gene sequencing and histological evidence. Our results showed inflammation in the intestines of juveniles at both stages of SUS. However, more severe tissue damage and the presence of bacterial clusters were detected only in the advanced stages of SUS. Differences in the composition and structure of the intestinal and skin bacterial community from early and advanced stages of SUS were detected, with more evident changes in the intestinal microbial communities. These findings suggest that SUS was not induced by a single pathogenic bacterium. Nevertheless, a decrease in the abundance of Vibrio and an increase in Halarcobacter (syn. Arcobacter) was observed, suggesting that these two bacterial groups could be keystone genera involved in SUS disease. [ABSTRACT FROM AUTHOR]

We conducted experiments with various growing conditions, both at sea and indoors, to explore the growth potential of Holothuria (Panningothuria) forskali Delle Chiaje, 1823 juveniles. Sea trials involved co-culture with European abalones (EA) or placement underneath European flat oysters (EO) or Pacific oysters (PO), using juveniles of 6–8 g initial weight. In sea-based conditions around summer (Apr–Sep), sea cucumbers grew best in EO at 0.94% d−1, followed by EA (0.88% d−1), both being in deep water (8–12 m), while sea cucumbers in the foreshore of a mega-tidal environment (PO) had the lowest growth (0.24% d−1). The indoor trial (IM) was performed with smaller individuals (≈0.3 g) and yielded a remarkable growth of 2.76% d−1 during summer (May–Sep). All experiments resulted in high survival rates, exceeding 80%. Additionally, we analysed fatty acid, amino acid, and stable isotope compositions of sea cucumbers' body walls, along with the pigment composition of their stomach contents. These analyses provided evidence that juveniles had distinct diets in each rearing condition, all differing from the diet of adults found in the wild. Our results also demonstrate that sea cucumbers do not compete for food resources in the shellfish production, which is crucial for their integration into multi-trophic aquaculture systems. However, whether sea cucumbers may have benefitted from the organic matter from shellfish faeces and pseudofaeces and/or grew on the biofilm growing on the cage walls remains to be elucidated. [ABSTRACT FROM AUTHOR]

Holothuria scabra, a commercially valuable yet ecologically vulnerable tropical holothuroid, has experienced a severe decline in its wild populations, especially in China. Genomic resources are crucial for the development of effective genomic breeding projects and stock conservation strategies to restore these natural populations. Until now, a high-quality, chromosome-level reference genome for H. scabra has not been available. Here, we employed Oxford Nanopore and Hi-C sequencing technologies to assemble and annotate a high-quality, chromosome-level reference genome of H. scabra. The final genome comprised 31 scaffolds with a total length of 1.19 Gb and a scaffold N50 length of 53.52 Mb. Remarkably, 1,191.67 Mb (99.95%) of the sequences were anchored to 23 pseudo-chromosomes, with the longest one spanning 79.75 Mb. A total of 34,418 protein-coding genes were annotated in the final genome, with BUSCO analysis revealing 98.01% coverage of metazoa_odb10 genes, marking a significant improvement compared to the previous report. These chromosome-level sequences and annotations will provide an essential genomic basis for further investigation into molecular breeding and conservation management of H. scabra. [ABSTRACT FROM AUTHOR]

The bakalili tradition has an impact on the exploitation rate of marine avertebrates and the economy of the Labuhan Bajo coastal community. The purpose of this study is to determine and analyze the targets, capture methods and utilization in the bakalili tradition. This study used interviews with respondents and direct surveys on the coast of Labuan Bajo. The results showed that the definition of bakalili is the activity of searching and catching organisms (clams, snails, sea cucumbers and others) at low tide in the intertidal zone. The bakalili activity is carried out from adolescence to the elderly. The bakalili activity is dominated by people who are female. Most of the sources of habit of this bakalili tradition are from families that have been carried out for generations with the aim of consumption and sale. The type of organism and the main focus of fishing is clams. The fishing method uses wooden tools with nails, knives and sickles. Most respondents stated that stock conditions were stable. On average, fishermen earn an income of Rp1,500,000 per month. [ABSTRACT FROM AUTHOR]

Sea cucumbers were stored live in 25% oxygen or 25 mg/mL of ascorbic acid for 7 days, for comparison purposes. The condition of the individuals was assessed through the sensory scores, bacterial communities, and biochemical indexes. The oxygen treatment extended preservation by 2 days compared to ascorbic acid. After 7 days, the total volatile basic nitrogen and the microbial content in all sea cucumbers were within acceptable limits. The actin degradation rate reached 1.3416 ± 0.03%, and cathepsin B and L increased by 94.6% and 59.1%, respectively, in the Control group. The quality decline of sea cucumbers during storage was caused by autolysis rather than spoilage organisms. (1) The evidence indicates autolysis occurred during sea cucumber storage, with 94.6% and 59.1% improvement in cathepsin B and L, respectively, and actin degradation of 1.3416 ± 0.03%. (2) The quality decline of sea cucumbers during storage was caused by autolysis rather than spoilage organisms. (3) The score evaluation revealed that the preservation time was two days longer with oxygen treatment (25%) than with ascorbic acid treatment (25 mg/mL). [ABSTRACT FROM AUTHOR]

The Salento peninsula in southern Italy (Mediterranean Sea) is a strip of land between the Adriatic and the Ionian Seas, both characterized by local regimes of currents, different geological and physical backgrounds, and quite diversified fauna. In this area, specimens of the sea cucumber Holothuria tubulosa (Brünnich, 1768) (Echinodermata) were collected at four stations in the spring and autumn of 2020 to investigate a possible symbiotic association with the inquiline fish Carapus acus (Brünnich, 1768). Among the collected holothurians, five pearlfish specimens were found in the body cavity of four H. tubulosa collected at 10 m of depth, in autumn, at "Grotta Verde" in Marina di Andrano, Lecce (Ionian Sea). More than half of the sea cucumbers from the latter station hosted the symbiont, suggesting the presence of a shallow population of C. acus inhabiting this coastal area. Furthermore, morphometric analysis carried out on the collected fish helped to shed light on the population dynamics characterizing this neglected species. This is the first report of C. acus from Apulian waters, allowing us to unite previously disjoined areas and providing essential baseline knowledge for planning future in-depth analysis of this difficult-to-study fish in a geographical area that is strategic in terms of the conservation of Mediterranean biodiversity. Furthermore, the range of preferred host species is extended, as C. acus was previously known to prefer other sea cucumber species such as Parastichopus regalis (Cuvier, 1817) instead of H. tubulosa. Finally, the finding of C. acus in a single station and in only one season is not trivial and delivers baseline useful information for future conservation purposes. [ABSTRACT FROM AUTHOR]

Sea cucumber Apostichopus japonicus is an ideal model organism for marine invertebrate aestivation; it annually enters a "sleeping state" for nearly 3 months when ambient water temperature range is 25–30 °C. The natural fasting is accompanied by remodeling the intestinal biota and function, which is a part of host biology and could affect the gut microbiota. We investigatesd the impact of annual aestivation on gut microbiota using high-throughput sequencing of 16S rRNA amplicons. Results reveal a notable alteration in the composition of gut bacteria during aestivation during which various indigenous families and genera that exhibit a preference for dietary glycans (e.g., family Rhodobacteraceae and Flavobacteriaceae) decreased, while the taxa capable of utilizing substrates derived from the host (e.g., genus Akkermansia and Prevotella) increased, and so did certain opportunistic pathogenic bacteria. Moreover, the investigation delved into the gut morphology and immunity response of A. japonicus and reveal that the intestine of A. japonicus undergoes substantial atrophy and degeneration during aestivation. However, there was an observed augmentation in the levels of acid and neutral mucin within mucous cells, as well as an enhanced immune defense response (as evidenced by increased gene expression of AjTLR3, LITAF, Ajp105, and LYZ). These results imply that the composition of sea cucumber gut microbiota differed between aestivation and active periods, which potentially affects the intestinal functions of the host and the symbiotic relationship between host and its microbiota over the active-aestivation cycle. [ABSTRACT FROM AUTHOR]

Manganese superoxide dismutase (MnSOD) is an antioxidant that exists in mitochondria and can effectively remove superoxide anions in mitochondria. In a dark, high-pressure, and low-temperature deep-sea environment, MnSOD is essential for the survival of sea cucumbers. Six MnSODs were identified from the transcriptomes of deep and shallow-sea sea cucumbers. To explore their environmental adaptation mechanism, we conducted environmental selection pressure analysis through the branching site model of PAML software. We obtained night positive selection sites, and two of them were significant (97F→H, 134K→V): 97F→H located in a highly conservative characteristic sequence, and its polarity change might have a great impact on the function of MnSOD; 134K→V had a change in piezophilic ability, which might help MnSOD adapt to the environment of high hydrostatic pressure in the deepsea. To further study the effect of these two positive selection sites on MnSOD, we predicted the point mutations of F97H and K134V on shallow-sea sea cucumber by using MAESTROweb and PyMOL. Results show that 97F→H, 134K→V might improve MnSOD's efficiency of scavenging superoxide anion and its ability to resist high hydrostatic pressure by moderately reducing its stability. The above results indicated that MnSODs of deep-sea sea cucumber adapted to deep-sea environments through their amino acid changes in polarity, piezophilic behavior, and local stability. This study revealed the correlation between MnSOD and extreme environment, and will help improve our understanding of the organism's adaptation mechanisms in deep sea. [ABSTRACT FROM AUTHOR]

Caspase (CASP) is a protease family that plays a vital role in apoptosis, development, and immune response. Herein, we reported the identification and characterization of two CASPs, AjCASPX1 and AjCASPX2, from the sea cucumber Apostichopus japonicus, an important aquaculture species. AjCASPX1/2 share similar domain organizations with the vertebrate initiator caspases CASP2/9, including the CARD domain and the p20/p10 subunits with conserved functional motifs. However, compared with human CASP2/9, AjCASPX1/2 possess unique structural features in the linker region between p20 and p10. AjCASPX1, but not AjCASPX2, induced marked apoptosis of human cells by activating CASP3/7. The recombinant proteins of AjCASPX2 and the CARD domain of AjCASPX2 were able to bind to a wide range of bacteria, as well as bacterial cell wall components, and inhibit bacterial growth. AjCASPX1, when expressed in Escherichia coli, was able to kill the host bacteria. Under normal conditions, AjCASPX1 and AjCASPX2 expressions were most abundant in sea cucumber muscle and coelomocytes, respectively. After bacterial infection, both AjCASPX1 and AjCASPX2 expressions were significantly upregulated in sea cucumber tissues and cells. Together, these results indicated that AjCASPX1 and AjCASPX2 were initiator caspases with antimicrobial activity and likely functioned in apoptosis and immune defense against pathogen infection. [ABSTRACT FROM AUTHOR]

In many tropical nations, coastal communities seek to manage their sea cucumber fisheries by establishing locally managed marine areas on their traditional fishing grounds. These managed areas can protect spawning stocks, however the extent to which they help to replenish nearby sea cucumber fisheries is debated, as nothing is known about the scales at which sea cucumber larvae disperse. In this study, we used genetic parentage analyses and statistical modelling to provide the first empirical measure of larval dispersal patterns for a sea cucumber species. We analysed tissue samples from 765 adult and 827 juvenile sandfish (Holothuria scabra) collected from five traditional fishing grounds of the Titan tribe, from Manus Province, Papua New Guinea. All adults were sampled from the Pere fishing grounds (the larval source area), with juveniles sampled from the Pere, Mbunai, Tawi, Timonai and Mbuke fishing grounds. Parentage analysis identified 15 juveniles that were the offspring of parents sampled from Pere fishing grounds, with six of these juveniles located in the same fishing grounds as their parents. The best-fit larval dispersal kernel predicted that the average H. scabra larvae travelled 15 km from its spawning location, with 50% of larvae settling within 6.7 km of their parents and 95% of larvae settling within 59 km of their parents. These results suggest that the Titan tribes' desire to protect their H. scabra spawning stocks by establishing a network of locally managed marine areas across 65 km of continuous coastline is a culturally appropriate strategy, which has merit from both an ecological and fisheries standpoint. [ABSTRACT FROM AUTHOR]

With the continuous rise of the sea cucumber aquaculture industry in China, the tropical sea cucumber aquaculture industry is also improving. However, research on the gut microorganisms of tropical sea cucumbers in captivity is scarce. In this study, high-throughput sequencing methods were used to analyze the gut microbial composition of Stichopus monotuberculatus and Holothuria scabra in the dry season and wet season of artificial environments. The results showed that 66 phyla were obtained in all samples, of which 59 phyla were obtained in the dry season, and 45 phyla were obtained in the wet season. The Tax4Fun analysis showed that certain gut bacterial communities affect the daily metabolism of two sea cucumber species and are involved in maintaining gut microecological balance in the gut of two sea cucumber species. In addition, compared with differences between species, PCoA and UPGMA clustering analysis showed the gut prokaryotes of the same sea cucumber species varied more in different seasons, indicating that the influence of environment was higher than the feeding choices of sea cucumbers under relatively closed conditions. These results revealed the gut bacterial community composition of S. monotuberculatus and H. scabra and the differences in gut bacterial structure between two sea cucumber species in different seasons were compared, which would provide the foundation for tropical sea cucumber aquaculture in the future. [ABSTRACT FROM AUTHOR]

Sea cucumbers are widely known for their powerful regenerative abilities, which allow them to regenerate a complete digestive tract within a relatively short time following injury or autotomy. Recently, even though the histological changes and cellular events in the processes of intestinal regeneration have been extensively studied, the molecular machinery behind this faculty remains unclear. In this study, tandem mass tag (TMT)-based quantitation was utilized to investigate protein abundance changes during the process of intestine regeneration. Approximately 538, 445, 397, 1012, and 966 differential proteins (DEPs) were detected (p < 0.05) between the normal and 2, 7, 12, 20, and 28 dpe stages, respectively. These DEPs also mainly focus on pathways of cell proliferation and apoptosis, which were further validated by 5-Ethynyl-2′-deoxyuridine (EdU) or Tunel-based flow cytometry assay. These findings provide a reference for a comprehensive understanding of the regulatory mechanisms of various stages of intestinal regeneration and provide a foundation for subsequent research on changes in cell fate in echinoderms. [ABSTRACT FROM AUTHOR]

Sea cucumbers are the second most diverse class among echinoderms. They are characterized by an elongated body and dermal ossicles in the body wall. Among the included groups in that class, the order Holothuriida encompasses many species of commercial interest. Faced with the threats of biodiversity loss resulting from the climate crisis and the advancement of cities, this study provides an overview of recent research involving the Holothuriida of the Brazilian Coast. Searches were carried out in the main periodical databases, using appropriate keywords, targeting publications on the subject in the period between 2000 and 2023. In total, 69 publications were found, most of them corresponding to scientific articles in international journals. Most of the studies come from the Northeast region in Brazil (56.52%). Regarding lines of research, those involving taxonomy and molecular analysis were the most prevalent. Over these 20 years, seven species constituted new occurrences. Of note are the studies focused on Holothuria (Halodeima) grisea, which makes up 39.13% of papers. Despite progress, little is known about morphological variations, genetic distance between populations, population densities, and on reproductive biology of species. Brazil has a vast, heterogeneous coastal area, with unique characteristics to which the species are adapted. The findings reinforce the importance to expand studies aiming on knowing the biodiversity, reproductive biology, and population densities of species. Such data are essential for the creation of public policies aimed at the conservation of species of Holothuriida and their habitats. [ABSTRACT FROM AUTHOR]