2-Butoxytetrahydrofuran, Isolated from Holothuria scabra, Attenuates Aggregative and Oxidative Properties of α-Synuclein and Alleviates Its Toxicity in a Transgenic Caenorhabditis elegans Model of Parkinson's Disease.

Aggregative α-synuclein and incurring oxidative stress are pivotal cascading events, leading to dopaminergic (DAergic) neuronal loss and contributing to clinical manifestations of Parkinson's disease (PD). Our previous study demonstrated that 2-butoxytetrahydrofuran (2-BTHF), isolated from Holothuria scabra (H. scabra), could inhibit amyloid-ß aggregation and its ensuing toxicity, which leads to Alzheimer's disease. In the present study, we found that 2-BTHF also attenuated the aggregative and oxidative activities of α-synuclein and lessened its toxicity in a transgenic Caenorhabditis elegans (C. elegans) PD model. Such worms treated with 100 µM of 2-BTHF showed substantial reductions in α-synuclein accumulation and DAergic neurodegeneration. Mechanistically, 2-BTHF, at this concentration, significantly decreased aggregation of monomeric α-synuclein and restored locomotion and dopamine-dependent behaviors. Molecular docking exhibited potential bindings of 2-BTHF to HSF-1 and DAF-16 transcription factors. Additionally, 2-BTHF significantly increased the mRNA transcripts of genes encoding proteins involved in proteostasis, including the molecular chaperones hsp-16.2 and hsp-16.49, the ubiquitination/SUMOylation-related ubc-9 gene, and the autophagy-related genes atg-7 and lgg-1. Transcriptomic profiling revealed an additional mechanism of 2-BTHF in α-synuclein-expressing worms, which showed upregulation of PPAR signaling cascades that mediated fatty acid metabolism. 2-BTHF significantly restored lipid deposition, upregulated the fat-7 gene, and enhanced gcs-1-mediated glutathione synthesis in the C. elegans PD model. Taken together, this study demonstrated that 2-BTHF could abrogate aggregative and oxidative properties of α-synuclein and attenuate its toxicity, thus providing a possible therapeutic application for the treatment of α-synuclein-induced PD.

Comparative Analysis of Gut Bacterial Community Composition in Two Tropical Economic Sea Cucumbers under Different Seasons of Artificial Environment.

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.

A Distinct Saponin Profile Drives an Olfactory-Mediated Aggregation in the Aquacultivated Sea Cucumber Holothuria scabra.

Intraspecific chemical communication between echinoderms has often been limited to prespawning aggregation. However, sea cucumber farmers have long observed year-round adult aggregation as a potential source of disease propagation and the suboptimal use of available sea pen acreage and food resources. In this study, through spatial distribution statistics, we demonstrated the significant aggregation of the aquacultivated sea cucumber Holothuria scabra both as adults in large sea-based pens and as juveniles in laboratory-based aquaria, proving that aggregation in these animals is not only observed during spawning. The role of chemical communication in aggregation was investigated using olfactory experimental assays. Our study established that the sediment that H. scabra feeds on as well as the water preconditioned by conspecifics induced positive chemotaxis in juvenile individuals. More specifically, through comparative mass spectrometry, a distinct triterpenoid saponin profile/mixture was identified to be a pheromone allowing sea cucumber intraspecific recognition and aggregation. This "attractive" profile was characterized as containing disaccharide saponins. This "attractive" aggregation-inducing saponin profile was, however, not conserved in starved individuals that were no longer attractive to other conspecifics. In summary, this study sheds new light on the pheromones in echinoderms. It highlights the complexity of the chemical signals detected by sea cucumbers and suggests a role of saponins well beyond that of a simple toxin.

The presence and distribution of gamma-aminobutyric acid and dopamine during the developmental stages of the sea cucumber, Holothuria scabra, with emphasis on settlement organs.

In the sea cucumber, Holothuria scabra, the competent larvae require main settlement organs (SOs), including the ciliary bands (CiBs), tentacles (Ts), podia (PDs), and cues from neurotransmitters, including gamma-aminobutyric acid (GABA) and dopamine (DA), for successful settlement. In the present study, we investigated the spatial distribution of GABA and DA in the developmental stages of H. scabra, with special emphasis on SOs by detecting immunoreactivity (-ir) against these two neurotransmitters. Strong GABA-ir and DA-ir cells and fibers were specifically detected in several SO structures, including CiBs, CiB cells (CiBCs), and long cilia (LCi), of H. scabra larvae. Additionally, we found intense GABA-ir and DA-ir cells in the epithelial lining of bud-papillae (BP) and mesothelium (Me) in the stem (S) region of Ts in larvae and juveniles. Intense GABA-ir and DA-ir were observed in the epineural nerve plexus (ENP) and hyponeural nerve plexus (HNP) of Ts in H. scabra pentactula and juvenile stages. Staining for these two neurotransmitters was particularly intense in the PDs and their nerve fibers. We also found significant changes in the numbers of GABA-ir and DA-ir-positive cells and intensities in the CiBs, Ts, and PDs during the developmental stages. Taken together, we are the first to report on the existence and distribution of GABAergic and dopaminergic systems in structures associated with the settlement. Our findings provide new and important insights into the possible functions of these two neurotransmitters in regulating the settlement of this sea cucumber species.

2-Butoxytetrahydrofuran and Palmitic Acid from Holothuria scabra Enhance C. elegans Lifespan and Healthspan via DAF-16/FOXO and SKN-1/NRF2 Signaling Pathways.

Extracts from a sea cucumber, Holothuria scabra, have been shown to exhibit various pharmacological properties including anti-oxidation, anti-aging, anti-cancer, and anti-neurodegeneration. Furthermore, certain purified compounds from H. scabra displayed neuroprotective effects against Parkinson's and Alzheimer's diseases. Therefore, in the present study, we further examined the anti-aging activity of purified H. scabra compounds in a Caenorhabditis elegans model. Five compounds were isolated from ethyl acetate and butanol fractions of the body wall of H. scabra and characterized as diterpene glycosides (holothuria A and B), palmitic acid, bis (2-ethylhexyl) phthalate (DEHP), and 2-butoxytetrahydrofuran (2-BTHF). Longevity assays revealed that 2-BTHF and palmitic acid could significantly extend lifespan of wild type C. elegans. Moreover, 2-BTHF and palmitic acid were able to enhance resistance to paraquat-induced oxidative stress and thermal stress. By testing the compounds' effects on longevity pathways, it was shown that 2-BTHF and palmitic acid could not extend lifespans of daf-16, age-1, sir-2.1, jnk-1, and skn-1 mutant worms, indicating that these compounds exerted their actions through these genes in extending the lifespan of C. elegans. These compounds induced DAF-16::GFP nuclear translocation and upregulated the expressions of daf-16, hsp-16.2, sod-3 mRNA and SOD-3::GFP. Moreover, they also elevated protein and mRNA expressions of GST-4, which is a downstream target of the SKN-1 transcription factor. Taken together, the study demonstrated the anti-aging activities of 2-BTHF and palmitic acid from H. scabra were mediated via DAF-16/FOXO insulin/IGF and SKN-1/NRF2 signaling pathways.

De novo genome assembly and annotation of Holothuria scabra (Jaeger, 1833) from nanopore sequencing reads.

BACKGROUND: Holothuria scabra is a costly gourmet and traditional Chinese tonic medicine. However, the lack of high-quality genome information hinders the genetic, phylogenetic, and bioactivator researches. OBJECTIVE: To construct high-quality genomic data of H. scabra and conduct genome-wide phylogenetic analysis. METHODS: The whole genome of a male H. scabra was sequenced based on Nanopore MinION platform, and the sequence was assembled by wtdbg2. Transcriptome sequencing was used to aid the gene annotation. Repeat sequences, non-coding RNA, pseudogene and gene functional annotation were analyzed. 750 single-copy gene families from ten species were applied to construct phylogenetic tree for evolutionary analysis by using the ML method. RESULTS: The H. scabra genome of 1.18 Gb (N50 = 1557,492 bp) with 500.42 Mb of putative repetitive sequences was assembled from a male H. scabra individual, and 16,642 protein-coding genes, 951 pseudogenes, 1791 motifs and 45,400 domains from the generated assembly were identified. The divergence time between H. scabra and its ancestor was estimated approximately 192.6 million years ago. H. scabra and A. japonicas joined together while sea urchin and sea star diverged about 440 Mya ago. Some key genes involved in notochord and gill slits development, skeleton degeneration and nervous system, as well as homeobox genes differ between H. scabra and Apostichopus japonicas. CONCLUSION: We report the first whole genome of H. scabra with expectation that this will be a valuable resource for genetic, phylogenetic, breading, molecular biology and bioactivator studies of sea cucumbers and other invertebrates.

Global knowledge on the commercial sea cucumber Holothuria scabra.

Holothuria scabra is one of the most intensively studied holothuroids, or sea cucumbers (Echinodermata: Holothuroidea), having been discussed in the literature since the early 19th century. The species is important for several reasons: (1) it is widely distributed and historically abundant in several shallow soft-bottom habitats throughout the Indo-Pacific, (2) it has a high commercial value on the Asian markets, where it is mainly sold as a dried product (beche-de-mer) and (3) it is the only tropical holothuroid species that can currently be mass-produced in hatcheries. Over 20 years have elapsed since the last comprehensive review on H. scabra published in 2001. Research on H. scabra has continued to accumulate, fuelled by intense commercial exploitation, and further declines in wild stocks over the entire distribution range. This review compiles data from over 950 publications pertaining to the biology, ecology, physiology, biochemical composition, aquaculture, fishery, processing and trade of H. scabra, presenting the most complete synthesis to date, including scientific papers and material published by local institutions and/or in foreign languages. The main goal of this project was to summarize and critically discuss the abundant literature on this species, making it more readily accessible to all stakeholders aiming to conduct fundamental and applied research on H. scabra, or wishing to develop aquaculture, stock enhancement and management programs across its geographic range.

Microplastic ingestion by the sandfish Holothuria scabra in Lampung and Sumbawa, Indonesia.

This study investigated the abundances and characteristics of microplastics in sediments and sandfish (Holothuria scabra) in Lampung and Sumbawa, Indonesia. Microplastics were found in 89.02% of all sandfish samples, with an average abundance of 2.01 ± 1.59 particles individual-1. The abundance of microplastics was 58.42 ± 24.33 particles kg-1 in surface sediments. Furthermore, there was a positive relationship between the abundance of microplastics in sandfish and sediments. Fragments and fibers with small-sized microplastics (300-1000 µm) were the most abundant types found in sandfish and sediments. Fourier-transform infrared (FTIR) analysis showed that polyethylene (30.08%), polypropylene (30.08%), polyurethane (12.20%), and polyethylene terephthalate (8.94%) were the most abundant polymers in the samples. Our results strongly indicate that microplastics in Lampung and Sumbawa originate from the fragmentation of large plastics. Better solid waste management in Indonesia is needed to reduce plastic waste leakage, which could become microplastics.

Identification and localization of growth factor genes in the sea cucumber, Holothuria scabra.

The sea cucumber Holothuria scabra is both an economically important species in Asian countries and an emerging experimental model for research studies in regeneration and medicinal bioactives. Growth factors and their receptors are known to be key components that guide tissue repair and renewal, yet validation of their presence in H. scabra has not been established. We performed a targeted in silico search of H. scabra transcriptome data to elucidate conserved growth factor family and receptor genes. In total, 42 transcripts were identified, of which 9 were validated by gene cloning and sequencing. The H. scabra growth factor genes, such as bone morphogenetic protein 2A (BMP 2A), bone morphogenetic protein 5-like (BMP5-like), neurotrophin (NT) and fibroblast growth factor 18 (FGF18), were selected for further analyses, including phylogenetic comparison and spatial gene expression using RT-PCR and in situ hybridization. Expression of all genes investigated were widespread in multiple tissues. However, BMP 2A, BMP5-like and NT were found extensively in the radial nerve cord cells, while FGF18 was highly expressed in connective tissue layer of the body wall. Our identification and expression analysis of the H. scabra growth factor genes provided the molecular information of growth factors in this species which may ultimately complement the research in regenerative medicine.

Intracellular Pathways of Holothuroid Oocyte Maturation Induced by the Thioredoxin Trx-REES.

In holothuroids, oocyte maturation is stopped in ovaries at the prophase I stage of meiosis. In natural conditions, the blockage is removed during the spawning by an unknown mechanism. When oocytes are isolated by dissection, the meiotic release can be successfully induced by a natural inducer, the REES (i.e., Rough Extract of Echinoid Spawn) that is used in aquaculture to obtain viable larvae in mass. A thioredoxin has recently been identified in the REES as the molecule responsible for holothuroid oocyte maturation. As a redox-active protein, thioredoxin is thought to reduce target proteins within the oocyte membrane and initiate an intracellular reaction cascade that leads to the unblocking of the oocyte meiosis. Our results allow us to understand additional steps in the intracellular reaction cascade induced by the action of thioredoxin on oocytes. Pharmacological agents known to have activating or inhibiting actions on oocyte maturation have been used (Forskolin, Isobutylmethylxanthine, Hypoxanthine, 6-dimethyaminopurine, Lavendustin, Genistein, Roscovitine, Cycloheximide). The effects of these agents were analysed on oocytes of the holothuroid Holothuria tubulosa incubated with or without REES and were compared to those obtained with another reducing agent, the dithiothreitol. Our results demonstrated that, at the opposite of dithiothreitol-induced oocyte maturation, thioredoxin-induced oocyte maturation is cAMP independent, but dependent of the presence of calcium in the seawater. Both pathways of induction require the activation of protein serine/threonine kinases.

Diterpene glycosides from Holothuria scabra exert the α-synuclein degradation and neuroprotection against α-synuclein-Mediated neurodegeneration in C. elegans model.

ETHNOPHARMACOLOGICAL RELEVANCE: Holothuria (Metriatyla) scabra Jaeger (H. scabra), sea cucumber, is the marine organism that has been used as traditional food and medicine to gain the health benefits since ancient time. Although our recent studies have shown that crude extracts from H. scabra exhibited neuroprotective effects against Parkinson's disease (PD), the underlying mechanisms and bioactive compounds are still unknown. AIM OF THE STUDY: In the present study, we examined the efficacy of purified compounds from H. scabra and their underlying mechanism on α-synuclein degradation and neuroprotection against α-synuclein-mediated neurodegeneration in a transgenic Caenorhabditis elegans PD model. MATERIAL AND METHODS: The H. scabra compounds (HSEA-P1 and P2) were purified and examined for their toxicity and optimal dose-range by food-clearance and lifespan assays. The α-synuclein degradation and neuroprotection against α-synuclein-mediated neurodegeneration were determined using transgenic C. elegans model, Punc-54::α-syn and Pdat-1:: α-syn; Pdat-1::GFP, respectively, and then further investigated by determining the behavioral assays including locomotion rate, basal slowing rate, ethanol avoidance, and area-restricted searching. The underlying mechanisms related to autophagy were clarified by quantitative PCR and RNAi experiments. RESULTS: Our results showed that HSEA-P1 and HSEA-P2 significantly diminished α-synuclein accumulation, improved motility deficits, and recovered the shortened lifespan. Moreover, HSEA-P1 and HSEA-P2 significantly protected dopaminergic neurons from α-synuclein toxicity and alleviated dopamine-associated behavioral deficits, i.e., basal slowing, ethanol avoidance, and area-restricted searching. HSEA-P1 and HSEA-P2 also up-regulated autophagy-related genes, including beclin-1/bec-1, lc-3/lgg-1, and atg-7/atg-7. RNA interference (RNAi) of these genes in transgenic α-synuclein worms confirmed that lc-3/lgg-1 and atg-7/atg-7 were required for α-synuclein degradation and DAergic neuroprotection activities of HSEA-P1 and HSEA-P2. NMR and mass spectrometry analysis revealed that the HSEA-P1 and HSEA-P2 contained diterpene glycosides. CONCLUSION: These findings indicate that diterpene glycosides extracted from H. scabra decreases α-synuclein accumulation and protects α-synuclein-mediated DAergic neuronal loss and its toxicities via lgg-1 and atg-7.

Methanolic Extract from Sea Cucumber, Holothuria scabra, Induces Apoptosis and Suppresses Metastasis of PC3 Prostate Cancer Cells Modulated by MAPK Signaling Pathway.

Sea cucumber, Holothuria scabra, is a well-known traditional Asian medicine that has been used for suppressing inflammation, promoting wound healing, and improving immunity. Moreover, previous studies demonstrated that the extract from H. scabra contains many bioactive compounds with potent inhibitory effect on tumor cell survival and progression. However, the effect of the methanolic extract from the body wall of H. scabra (BWMT) on human prostate cancer cells has not yet been investigated. In this study, we aimed to investigate the effects and underlying mechanism of BWMT on prostate cancer cell viability and metastasis. BWMT was obtained by maceration with methanol. The effect of BWMT on cell viability was assessed by MTT and colony formation assays. The intracellular ROS accumulation was evaluated using a DCFH-DA fluorescence probe. Hoechst 33342 staining and Annexin V-FITC/PI staining were used to examine the apoptotic-inducing effect of the extract. A transwell migration assay was performed to determine the anti-metastasis effect. BWMT significantly reduced cell viability and triggered cellular apoptosis by accumulating intracellular ROS resulting in the upregulation of JNK and p38 signaling pathways. In addition, BWMT also inhibited the invasion of PC3 cells by downregulating MMP-2/-9 expression via the ERK pathway. Consequently, our study provides BWMT from H. scabra as a putative therapeutic agent that could be applicable against prostate cancer progression.

Neuroprotective and Neurorestorative Effects of Holothuria scabra Extract in the MPTP/MPP+-Induced Mouse and Cellular Models of Parkinson's Disease.

Extracts from Holothuria scabra (HS) have been shown to possess anti-inflammation, anti-oxidant and anti-cancer activities. More recently, it was shown to have neuroprotective potential in Caenorhabditis elegans PD model. Here, we assessed whether HS has neuroprotective and neurorestorative effects on dopaminergic neurons in both mouse and cellular models of PD. We found that both pre-treatment and post-treatment with HS improved motor deficits in PD mouse model induced with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) as determined by grid walk test. This was likely mediated by HS protective and restorative effects on maintaining the numbers of dopaminergic neurons and fibers in both substantia nigra pars compacta (SNpc) and striatum. In a cellular model of PD, HS significantly attenuated 1-methyl-4-phenylpyridinium (MPP+)-induced apoptosis of DAergic-like neurons differentiated from SH-SY5Y cells by enhancing the expression of Bcl-2, suppressing the expression of cleaved Caspase 3 and preventing depolarization of mitochondrial membrane. In addition, HS could stimulate the expression of tyrosine hydroxylase (TH) and suppressed the formation of α-synuclein protein. Taken together, our in vivo and in vitro findings suggested that HS is an attractive candidate for the neuroprotection rather than neurorestoration in PD.

An ethyl-acetate fraction of Holothuria scabra modulates inflammation in vitro through inhibiting the production of nitric oxide and pro-inflammatory cytokines via NF-κB and JNK pathways.

Sea cucumber, Holothuria scabra, is an echinoderm marine animal that has long been used as a traditional therapeutic in various diseases due to its chemical composition and protein enrichment. Many researchers have extensively studied the efficacy of sea cucumber extracts for many health benefits in recent years. Inflammation is a complex process involved in pro-/anti-inflammatory cytokine products. However, the role of the H. scabra extracts in anti-inflammation and its molecular regulations has not been apparently elucidated yet. In this study, we investigated the anti-inflammatory effect of H. scabra extracts by using lipopolysaccharide (LPS) from E. coli to induce an inflammatory response in RAW264.7 macrophage. It was found that ethyl acetate fraction of H. scabra extracts (EAHS) inhibited pro-inflammatory cytokines synthesis at both the transcriptional and translational levels, notably nitric oxide (NO), inducible nitric oxide synthase (iNOS), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), and prostaglandin E2 (PGE2). In addition, EAHS was able to downregulate IκB/NF-κB, and JNK expressions. These effects may be influenced by high contents of phenolic compound and triterpene glycosides in EAHS. Therefore, EAHS might have the potential to be developed as a natural anti-inflammatory agent.

Acclimation capability inferred by metabolic performance in two sea cucumber species from different latitudes.

The notion that thermal specialists from tropical regions live closer to their temperature limits than temperate eurytherms, seems too generalized. Species specific differences in physiological and biochemical stress reactions are linked to key components of organism fitness, like metabolic capacity, which indicates that acclimation potential across latitudes might be highly diverse rather than simplistic. In this study the exposure of a tropical (Holothuria scabra) and a temperate (Holothuria forskali) sea cucumber species to identical cold- and warm-acclimation stress was compared using the key metabolic parameters, respiration rate, enzyme activity (ETS, LDH, IDH), and energy reserve fractions (lipid, carbohydrate and protein). Results show much broader respiratory adjustments, as response to temperature change, in H. scabra (2-30 µgO2*gww-1*h-1) compared to H. forskali (1.5-6.6 µgO2*gww-1*h-1). Moreover, the tropical species showed clearly pronounced up and down regulation of metabolic enzymes and shifts in energy reserves, due to thermal acclimation, while the same metabolic indicators remained consistent in the temperate species. In summary, these findings indicate enhanced metabolic plasticity in H. scabra at the cost of elevated energy expenditures, which seems to favor the tropical stenotherm in terms of thermal acclimation capacity. The comparison of such holistic metabolic analyses between conspecifics and congeners, may help to predict the heterogeneous effects of global temperature changes across latitudinal gradients.

Holothuria scabra extracts possess anti-oxidant activity and promote stress resistance and lifespan extension in Caenorhabditis elegans.

Holothuria scabra is a sea cucumber that is mostly found in the Indo-Pacific region including Thailand. Extracts from many sea cucumbers possess pharmacological activities proposed to benefit human health. In this study, we investigated the anti-oxidant and anti-ageing activities of extracts from H. scabra by using Caenorhabditis elegans as a model organism. Parts of H. scabra were solvent-extracted and divided into nine fractions including whole body-hexane (WBHE), whole body-ethyl acetate (WBEA), whole body-butanol (WBBU), body wall-hexane (BWHE), body wall-ethyl acetate (BWEA), body wall-butanol (BWBU), viscera-hexane (VIHE), viscera-ethyl acetate (VIEA), and viscera-butanol (VIBU). All fractions of the extracts were tested for anti-oxidant activities by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays and for anti-ageing effects by lifespan assays using C. elegans as a model. The results showed anti-oxidant properties in all fractions with the highest activity shown by the DPPH assay in WBBU (EC50 = 3.12 ±â€¯0.09 mg/ml), and by the ABTS assay in WBHE (EC50 = 0.31 ±â€¯0.10 mg/ml). In lifespan assays the highest anti-ageing effect was detected in WBBU- and BWEA-treated C. elegans with increased mean lifespans of 8.12% and 4.77%, respectively. Furthermore, WBBU and BWEA-treated C. elegans exhibited significantly higher resistance against heat shock and paraquat-induced oxidative stresses than controls. By using LC-MS/MS, both extracts were characterized to contain triterpene glycosides as the main bioactive components. To explore mechanisms of H. scabra extracts on longevity and stress resistance, worms with genetic mutations in anti-ageing pathways were analyzed and showed that WBBU and BWEA did not prolong the lifespan of daf-16, age-1, sir-2.1, jnk-1, sek-1, and osr-1 mutants, suggesting that these genetic pathways are involved in mediating the anti-ageing effects of the H. scabra extracts. Moreover, WBBU and BWEA enhanced the nuclear translocation of the FoxO/DAF-16 transcription factor, and increased mRNA expression of this gene and its downstream targets sod-3, hsp12.3, and hsp16.2. In conclusion, this study strongly demonstrates anti-oxidant and anti-ageing properties of H. scabra extracts containing triterpene glycosides, which, in the C. elegans model, may be mediated via the insulin/IGF-1 signaling (IIS)-DAF-16 pathway.

Distribution and dynamic expression of serotonin and dopamine in the nervous system and ovary of Holothuria scabra during ovarian maturation.

In the present study, the distribution and dynamic expression of serotonin and dopamine in the nervous system and ovary of the sea cucumber, Holothuria scabra, during different ovarian stages were investigated. We found that serotonin-immunoreactivity was more intense in the neurons and neuropils of the outer ectoneural part, the inner hyponeural part, and the wall of hyponeural canal of radial nerve cord during the mature stages of ovarian cycle, whereas dopamine-immunoreactivity was detected at a higher intensity in these tissues during the early stages. Both neurotransmitters were detected in the ectoneural part of the nerve ring. In the ovary, serotonin intensity was more intense in the cytoplasm of late oocytes, while dopamine-immunoreactivity was more intense in the early stages. The changes in the levels serotonin in the radial nerve cord and oocytes are incremental towards the late stages of ovarian maturation. In contrast, dopamine levels in the nervous tissues and oocytes were more intense in early stages and became decremental towards the late stages. These findings suggest that serotonin and dopamine may have opposing effects on ovarian development in this sea cucumber species.

Separation, purification, structures and anticoagulant activities of fucosylated chondroitin sulfates from Holothuria scabra.

In this study, a new fucosylated chondroitin sulfate (HsG) with an average molecular weight of 69.1 kDa was isolated from sea cucumber Holothuria scabra. We investigated the structure of the HsG by adopting monosaccharide composition analysis, disaccharide composition analysis, IR,1H and13C NMR spectra and methylation analysis. According to methylation results of desulfated/carboxyl-reduced polysaccharides and the analysis of unsaturated disaccharides generated through the enzymolysis of the defucosed polysaccharides, it is shown that each branch is formed by one fucopyranosyl residue, wherein 55.7% of the fucopyranosyl residues are linked to the O-6 position of the N-acetylgalactosamine moiety, 21.2% of the fucopyranosyl residues are linked to the O-3 position of ß-d-glucuronic acid, 13.0% of the fucopyranosyl residues are linked to the O-4 positions of the N-acetylgalactosamine moiety, and 10.1% of the fucopyranosyl residues are not linked to sulfate groups on the backbone. The backbone →4)GlcUAß(1 → 3)GalNAcß(1→ and sulfated fucose branches were composed of the ß-d-glucuronic acid, N-acetyl-ß-d- galactosamine, α-l-fucose and sulfate groups by the molar ratio of 1:1.72:2.34:3.29. The anticoagulant activities of the HsG was evaluated and compared with heparin. The result showed that the HsG could prolong the activated partial thromboplastin time.

Holothuria scabra extracts exhibit anti-Parkinson potential in C. elegans: A model for anti-Parkinson testing.

OBJECTIVES: Parkinson's disease (PD) is associated with aggregation of α-synuclein and selective death of dopaminergic (DA) neurons in the substantia nigra, thereby leading to cognitive and motor impairments. Nowadays, the drugs commonly used for PD treatment, such as levodopa, provide only symptomatic relief. Therefore, seeking new drugs against PD, especially from plants and marine organisms, is one of the major research areas to be explored. This study aimed to investigate the anti-Parkinson activity of the extracts from the sea cucumber, Holothuria scabra, by using Caenorhabditis elegans as a model. METHODS: H. scabra was solvent-extracted and subdivided into six fractions including whole body-ethyl acetate (WBEA), body wall-ethyl acetate (BWEA), viscera-ethyl acetate (VIEA), whole body-butanol (WBBU), body wall-butanol (BWBU), and viscera-butanol (VIBU). The extracts were tested in C. elegans BZ555 strain expressing the green fluorescent protein (GFP) specifically in the DA neurons and NL5901 strain expressing human α-synuclein in the muscle cells. RESULTS: WBEA, BWEA, and WBBU fractions of H. scabra extracts at 500 µg/ml significantly attenuated DA neuron-degeneration induced by selective cathecholamine neurotoxin 6-hydroxydopamine (6-OHDA) in the BZ555 strain. Moreover, the extracts also reduced α-synuclein aggregation and restored lipid content in NL5901, as well as improved food-sensing behavior and prolonged lifespan in the 6-OHDA-treated wild-type strain. DISCUSSION: The study indicated that the H. scabra extracts have anti-Parkinson potential in the C. elegans model. These findings encourage further investigations on using the H. scabra extract, as well as its active constituent compounds, as a possible preventive and/or therapeutic intervention against PD.

Transcriptomic discovery and comparative analysis of neuropeptide precursors in sea cucumbers (Holothuroidea).

Neuropeptides synthesized and released by neuronal cells play important roles in the regulation of many processes, e.g. growth, feeding, reproduction, and behavior. In the past decade, next-generation sequencing technologies have helped to facilitate the identification of multiple neuropeptide genes in a variety of taxa, including arthropods, molluscs and echinoderms. In this study, we extend these studies to Holothuria scabra, a sea cucumber species that is widely cultured for human consumption. In silico analysis of H. scabra neural and gonadal transcriptomes enabled the identification of 28 transcripts that encode a total of 26 bilaterian and echinoderm-specific neuropeptide precursors. Furthermore, publicly available sequence data from another sea cucumber, Holothuria glaberrima, allowed a more in-depth comparative investigation. Interestingly, two isoforms of a calcitonin-type peptide precursor (CTPP) were deduced from the H. scabra transcriptome - HscCTPP-long and HscCTPP-short, likely the result of alternative splicing. We also identified a sea cucumber relaxin-type peptide precursor, which is of interest because relaxin-type peptides have been shown to act as gonadotropic hormones in starfish. Two neuropeptides that appear to be holothurian-specific are GLRFA, and GN-19. In H. scabra, the expression of GLRFA was restricted to neural tissues, while GN-19 expression was additionally found in the longitudinal muscle and intestinal tissues. In conclusion, we have obtained new insights into the neuropeptide signaling systems of holothurians, which will facilitate physiological studies that may enable advances in the aquaculture of sea cucumbers.