Black Sea Cucumber Research Articles

Molecular Networking-Based Analysis of Cytotoxic Saponins from Sea Cucumber Holothuria atra.

The saponin composition of a specimen of black sea cucumber, Holothuria atra collected in the Persian Gulf was studied by a combined approach including LC-MS/MS, Molecular Networking, pure compound isolation, and NMR spectroscopy. The saponin composition of Holothuria atra turned out to be more complex than previously reported. The most abundant saponins in the extract (1–4) were isolated and characterized by 1D- and 2D-NMR experiments. Compound 1 was identified as a new triterpene glycoside saponin, holothurin A5. The side chain of the new saponin 1, unprecedented among triterpene glycosides, is characterized by an electrophilic enone function, which can undergo slow water or methanol addition under neutral conditions. The cytotoxic activity of compounds 1–4, evaluated on the human cervix carcinoma HeLa cell line, was remarkable, with IC50 values ranging from 1.2 to 2.5 µg/mL.

The complete mitochondrial genomes from three body color variants of sea cucumbers, Apostichopus japonicus (Selenka, 1867)

To study the intraspecific variation of the sea cucumber, Apostichopus japonicus, we sequenced three complete mitochondrial genomes, especially from different body color variants (green, black, and red) of Apostichopus japonicus in Geomum-do, Republic of Korea. The full lengths of green, black, and red sea cucumber mitochondrial genomes are 16,106 bp, 16,096 bp, and 16,107 bp, respectively. They all contain 37 genes (13 protein-coding genes, 2 rRNAs, and 22 tRNAs), and have an average 38.0% of GC ratio. Two hundred thirty eight single nucleotide polymorphisms and 26 insertion and deletions were identified among three sea cucumber mitochondrial genomes. The phylogenetic analysis of A. japonicus with additional 14 available A. japonicus and two Parastichopus mitochondrial genomes were used as outgroups shows somewhat distinct three clades with body color patterns. Furthermore, there is no clear phylogenetic separation among Korean, Chinese, and Japanese individuals. These data will provide new insights and to facilitate the rapid growth of the sea cucumber aquaculture industry and its breeding programs.

Anti-Parkinson activity of bioactive substances extracted from Holothuria leucospilota

Parkinson’s disease (PD) is a well-known neurodegenerative disorder characterized by dopaminergic (DA) neuron loss and α-synuclein aggregation. Recent study revealed that the extracts from sea cucumber, Holothuroidea spp., exhibited neuroprotective and lifespan extension effects in Caenorhabditis elegans model. Interestingly, the black sea cucumber, Holothuria leucospilota, possesses body wall and a specialized organ called cuvierian tubules containing high amount of bioactive compounds. In this study, the neuroprotective effects of the body wall (BW) and cuvierian tubules (CT) from this sea cucumber against PD were evaluated using C. elegans as a model. H. leucospilota were extracted using ethanol (ET), ethyl acetate (EA), butanol (BU) and aqueous (AQ) fractions. Extracts from these fractions were used to treat the 6-OHDA-induced BZ555 and α-synuclein expressing NL5901 strains of C. elegans. Treatment with ET, EA, BU and AQ fractions of H. leucospilota extracts could significantly prevent degeneration of DA neurons in 6-OHDA-induced worms, improve food-sensing behavior mediated by DA neurons, and up-regulate cat-2 and sod-3 gene expressions. These results indicate the neuroprotective activity of the extracts which may be attributed to the anti-oxidant activity of the bioactive compounds. Moreover, α-synuclein aggregation was significantly reduced together with the recovery of lipid deposition upon the treatment with H. leucospilota extracts. In addition, treatment with H. leucospilota extracts was able to increase the lifespan of 6-OHDA-induced N2. NMR analysis revealed the major chemical components in the effective EA fractions were terpenoids, steroids, saponins, and glycosides. In summary, H. leucospilota extracts exhibited anti-Parkinson effect in both toxin-induced and transgenic C. elegans models of PD. Further study will be performed to elucidate the most effective anti-PD molecules which will lead to the development of anti-PD drug.

In vitro oocyte maturation by radial nerve extract and early development of the black sea cucumber (Holothuria leucospilota)

The popularity of sea cucumbers has led to overexploitation of wild populations and increasing need to develop their aquaculture. In vitro induction of oocyte maturation followed by fertilization represents an innovative approach that could help increase their production. The inducers of oocyte maturation are naturally synthesised within neural tissue, which in sea cucumbers includes longitudinal radial nerves and a circumoral nerve ring. In this study, we showed that reproductive maturation of the black sea cucumber (Holothuria leucospilota Brandt, 1835) in South-East Queensland, Australia, peaked in December, based on biometric analysis of gonads. Radial nerve extract (RNE; 233 μg/ml) prepared from reproductive mature females induced in vitro oocyte maturation at 98.9% efficiency, based on germinal vesicle breakdown. RNE-matured oocytes were fertilized (99%) with conspecific sperm and larvae developed to late auricularia stage (25 days post-fertilization). The NGIWYamide neuropeptide (cubifrin), which induces oocyte maturation in the sea cucumber Apostichopus japonicus, could not induce oocyte maturation in H. leucospilota. These results provide information that could be used for large-scale artificial breeding of H. leucospilota, and a platform towards the identification of the bioactive RNE factor(s).

Megadenus atrae n. sp., an endoparasitic eulimid gastropod (Mollusca) from the black sea cucumber Holothuria atra Jaeger (Aspidochirotida: Holothuriidae) in the Indo-West Pacific.

An eulimid gastropod, Megadenus atrae n. sp., endoparasitic in the cloacal chamber of the black sea cucumber Holothuria atra Jaeger is described from Okinawa, Japan, as the fifth species of the genus. Conspecific specimens have also been found from southeast India, northeast Australia and New Caledonia. The generic assignment is justified by the presence of (i) a thick, long proboscis that bears a large fold (pseudopallium) near the base and a collar-like structure at the middle, (ii) a thin, globose shell that is covered by the pseudopallium, and (iii) sexual dimorphism with the female generally larger than the male. The new species is distinguishable from the four previously described congeners by its cauldron-shaped pseudopallium, moderately-developed collar of the proboscis and rounded basal lip of the shell. The comparisons of the size and sex of solitary and paired individuals support a previous hypothesis that the species of Megadenus Rosén, 1910 are protandrous with environmental sex determination. The present species occurs mostly as monogamous pairs despite its very low population density, implying that the presence of a conspecific individual acts as a cue for larval settlement. Both mechanisms would increase individual reproductive success in such permanent parasites with low prevalence and abundance as the species of Megadenus.

Anticancer potency of black sea cucumber (Holothuria atra) from Mentawai Islands, Indonesia

Introduction: The source of bioactive compounds believed to have strong anticancer potency is derived from sea cucumber. Black sea cucumber (Holothuria atra) is a dominant species in Mentawai Islands, West Sumatera, Indonesia. Key factor compound that acts as anticancer in sea cucumber extract is tritepenoid also known as Frondoside A. The purpose of this study was to determine the effectiveness of the active compound taken from black sea cucumber as anticancer. Methods: Methods used was experimental laboratory. Anticancer activity of black sea cucumber was determined by using the MTT assay cytotoxic test to measure the IC50. Cytotoxic test was conducted with Supris clone-1 (SP-C1) derived from cloned lymphadenopathy of patients with oral squamous cell carcinoma on lingual part. Results: It was found that the compounds contained in black sea cucumber has strong anticancer activity (IC50 = 5.25 μL/mL) against SP-C1. Conclusion: Black sea cucumber extract has strong cytotoxic effects against cancer cells SP-C1, therefore black sea cucumber extract potentially developed as a new source of cancer medicine.

The distribution of macrobenthic epifauna in the Far Eastern Marine Reserve based on remote underwater video data

The spatial distribution of epifauna in the Far Eastern Marine Reserve was examined using a remotely operated vehicle. The abundance and distribution patterns of the sea stars Patiria pectinifera, Distolasterias nipon, and Asterias amurensis, as well as those of brittle stars, the black sea cucumber Cucumaria japonica, the sea urchin Strongylocentrotus intermedius, the ascidian Halocynthia aurantium, hermit crabs, and the Japanese scallop Mizuhopecten yessoensis were determined in the South Section of the Reserve. The average biomass of five dominant epifaunal species ranged from 51.0 to 87.4% of the average biomass of the softbottom communities.

THE OCCURENCE & DISTRIBUTION OF TWO BLACK SEA CUCUMBER SPECIES IN POMBO ISLAND, CENTRAL MALUKU (INDONESIA)

The so called “black sea cucumber” are found in Indonesia as several species including Holothuria atra, H. leucospilota, H. coluber, H. excellens and H. turriscelsa. The local community of Wainure village near Pombo Island in central Maluku had reported that most sea cucumbers inhabiting the island are the black sea cucumbers or locally known as “teripang hitam.” They are occasionally consumed but not exploited excessively by the locals. The goals of this study are to identify the species of black sea cucumbers inhabiting Pombo Island and map their distribution to understand the microhabitats of black sea cucumber. Two field surveys conducted in March and April 2014 collected more than 550 individuals of black sea cucumbers that belong to two species Holothuria (Halodeima) atra Jaeger, 1833, and Holothuria (Mertensiothuria) leucospilota Brandt, 1835. Furthermore, distribution maps of these two species show that they are found only along the SE to SW coast of the island. Such distribution may relate to the availability of marine vegetation, as well as boulders and stones that provide shelters to the organism. The distribution maps also show that H. atra has a wider distribution than H. leucospilota in Pombo Island. This may be due to the semi-cryptic habit of H. Leucospilota’s (i.e. hiding its posterior body under rocks or crevices), making its distribution restricted to areas that provide ample shelters.

Comparison on proximate composition and nutritional profile of red and black sea cucumbers (Apostichopus japonicus) from Ulleungdo(Island) and Dokdo(Island), Korea

The proximate composition, fatty acid, and amino acid profile of the body wall and viscera of each red and black sea cucumber (Apostichopus japonicus) from Ulleungdo(Island) and Dokdo(Island) in Korea were compared. Moisture, ash, crude protein, and crude lipid contents ranged between 80.26–91.49, 2.57–6.85, 1.13–3.99, and 0.14–2.12%, respectively. The fatty acid values varied depending on the species and the regions of collection. The anteiso C17:0, C16:1Δ9, C17:1Δ7, C18:1Δ11, and C16:2Δ7 were only observed in the body wall. Among the tested fatty acids, the C18:1Δ11 was specific in red sea cucumber, and C20:4Δ6 (17.7%) and C20:5Δ3 (17.6%) were the predominant polyunsaturated fatty acids (PUFA) in all samples. The contents of the C18:0 dimethyl acetal (C18:0 DMA), C16:1Δ7, C16:1Δ5, and C18:1Δ5 were compared in details. Total amino acids (TAA) of body wall were 1.3–1.9 times higher than those of viscera. Glutamic acid and aspartic acid constituted the major TAA of sea cucumbers. The ratio of essential amino acids (EAA): nonessential amino acids (NEAA) on TAA ranged from 1.15 to 0.67 of sea cucumbers. Viscera of red sea cucumber from Dokdo(Island) were rich in free amino acids (FAA) and showed a high content in leucine.

Contamination levels for lead, cadmium and mercury in marine gastropods, echinoderms and tunicates

As part of a specific monitoring programme, total lead (Pb), cadmium (Cd) and mercury (Hg) concentrations in marine gastropods (common winkle, common whelk, abalone and murex), echinoderms (purple sea urchin and black sea cucumber) and tunicates (an ascidian species) were investigated by the French National Reference Laboratory (NRL) for trace elements in foodstuffs of animal origin. These elements were analysed by atomic absorption spectrometry in order to evaluate the safety of these species for human consumption. The highest levels of Hg and Cd were found in murexes, 0.185 mg kg −1 and 0.853 mg kg −1, respectively; whereas the highest level of Pb was detected in ascidians (0.505 mg kg −1). Hg and Pb concentrations were always below the maximum levels set by the European legislation (0.5 mg Hg kg −1 and 1.5 mg Pb kg −1 wet mass) and for Cd, only 2 samples of murex (2.09 ± 0.42 mg kg −1 and 2.33 ± 0.46 mg kg −1) exceeded the maximum level set by French legislation of 2.0 mg kg −1 wet mass.

Heavy metal accumulation in tissue/organs of a sea cucumber, Holothuria leucospilota

Holothuria leucospilota Brandt, the large black sea cucumber, is a non-selective deposit feeder, and is commonly found in the bottom of shallow waters in Hong Kong, where the sediments are often polluted with heavy metals. This study was designed to test the possibility of heavy metal accumulation by the sea cucumber at two sites in Hong Kong. Atomic absorption spectrophotometer was used to measure Cu and Zn concentrations in various tissue/organs of the animal as well as in the sediments. The result indicated that H. leucospilota accumulated zinc in the longitudinal muscle bands (97.27–98.07 ppm in dry weight) and in the respiratory tree (83.92–89.64 ppm in dry weight). Copper concentrations in these two organs were much lower than that of zinc. After the animals were kept in the aquarium without sediment for40 days, zinc concentration of the longitudinal muscle and respiratory tree decreased by 48% and 39%respectively whereas copper concentration remained unchanged. The concentrations of zinc and copper in the sediment at the two sites differed significantly but the metal level in the animals from the two sites were similar, suggesting that this sea cucumber was not an ideal bioindicator of heavy metal pollution in the sediment.