Query: Holothuria tubulosa

title: Contribution of sea cucumber Holothuria tubulosa on organic load reduction from fish farming operation
abstract: An investigation was carried out in the field and in the laboratory in order to evaluate the contribution of sea cucumber Holothuria tubulosa on organic load reduction from fish farming in the Eastern Mediterranean. Five experimental cages and three double systems of seawater aquaria were used for this purpose. The mean reduction of OM and OC was 30.73% and 58.58% respectively. Moreover, the mean absorption efficiency of OM and OC during transit in the intestine of H. tubulosa was 43.40% and 54.65% respectively. One way ANOVA indicated significant differences on OM and OC accumulation rate between holothurians and control (p

title: Bioaccumulation of perfluoroalkyl substances in marine echinoderms: Results of laboratory scale experiments with Holothuria tubulosa Gmelin, 1791.
abstract: Bioaccumulation of six perfluoroalkyl substances (PFAS) was assessed using the marine echinoderm Holothuria tubulosa Gmelin, 1791. Batch experiments were conducted to establish the relationship between concentrations in water, sediment and biota over 197 days. The sample treatment for the determination of compounds involves steps of lyophilization, solvent extraction and clean up of the extracts with dispersive sorbents. PFAS were then analysed by liquid chromatography tandem mass spectrometry. During contaminant exposure, detectable levels of compounds were found in all samples collected. Mean concentrations of selected PFAS were higher in sediments than in water samples. This fact is explained by the strong adsorption of these compounds into sediments. Sediment water distribution coefficients (log Kd) were in the range 0.11 (PFBuA) to 2.46 (PFOA) Beside this, PFAS accumulation was observed in Holothuria tubulosa organisms. The uptake of PFAS was very rapid, reaching the maximum between 22 and 38 days of assay. Bioaccumulation factors (mean log BAF: 1.16 4.39) and biota sediment accumulation factors (mean log BSAF: 1.37 2.89) indicated a high bioaccumulation potential for the target compounds. Both parameters increased with perfluoroalkyl chain length (R2 0.93; p 0.05) In organ specific distributions of PFAS, greater concentrations were found in intestine than in gonads. Also, male specimens showed higher concentration levels than female (student t test: tcal 2.788, ttab 2.262; p 0.05) These data provide a detailed accounting of PFAS fate and distribution in the marine environment highlighting accumulation at lower trophic levels, a potential source for contamination in higher organisms.

title: A Synthetic Derivative of Antimicrobial Peptide Holothuroidin 2 from Mediterranean Sea Cucumber (Holothuria tubulosa) in the Control of Listeria monocytogenes
abstract: Due to the limited number of available antibiotics, antimicrobial peptides (AMPs) are considered antimicrobial candidates to fight difficult to treat infections such as those associated with biofilms. Marine environments are precious sources of AMPs, as shown by the recent discovery of antibiofilm properties of Holothuroidin 2 (H2) an AMP produced by the Mediterranean sea cucumber Holothuria tubulosa. In this study, we considered the properties of a new H2 derivative, named H2d, and we tested it against seven strains of the dangerous foodborne pathogen Listeria monocytogenes. This peptide was more active than H2 in inhibiting the growth of planktonic L. monocytogenes and was able to interfere with biofilm formation at sub minimum inhibitory concentrations (MICs) Atomic level molecular dynamics (MD) simulations revealed insights related to the enhanced inhibitory activity of H2d, showing that the peptide is characterized by a more defined tertiary structure with respect to its ancestor. This allows the peptide to better exhibit an amphipathic character, which is an essential requirement for the interaction with cell membranes, similarly to other AMPs. Altogether, these results support the potential use of our synthetic peptide, H2d, as a template for the development of novel AMP based drugs able to fight foodborne that are resistant to conventional antibiotics.

title: Cytotoxic Potential of the Coelomic Fluid Extracted from the Sea Cucumber Holothuria tubulosa against Triple Negative MDA MB231 Breast Cancer Cells
abstract: Growing evidence has demonstrated that the extracts of different holothurian species exert beneficial effects on human health. Triple negative breast cancers (TNBC) are highly malignant tumors that present a poor prognosis due to the lack of effective targeted therapies. In the attempt to identify novel compounds that might counteract TNBC cell growth, we studied the effect of the exposure of the TNBC cell line MDA MB231 to total and filtered aqueous extracts of the coelomic fluid obtained from the sea cucumber Holoturia tubulosa, a widespread species in the Mediterranean Sea. In particular, we examined cell viability and proliferative behaviour, cell cycle distribution, apoptosis, autophagy, and mitochondrial metabolic/cell redox state. The results obtained indicate that both total and fractionated extracts are potent inhibitors of TNBC cell viability and growth, acting through both an impairment of cell cycle progression and mitochondrial transmembrane potential and a stimulation of cellular autophagy, as demonstrated by the increase of the acidic vesicular organelles and of the intracellular protein markers beclin 1, and total LC3 and LC3 II upon early exposure to the preparations. Identification of the water soluble bioactive component(s) present in the extract merit further investigation aiming to develop novel prevention and/or treatment agents efficacious against highly metastatic breast carcinomas.

title: Spawning and rearing of Holothuria tubulosa: A new candidate for aquaculture in the Mediterranean region
abstract: Holothuria tubulosa (Gmelin, 1788) has recently shown an increased demand in Asian markets, becoming one of the intensively exploited holothurian species in the Mediterranean Sea. A risk is that over harvesting is likely affecting both the species' natural stocks and the benthic communities. In this scenario, sea ranching and restocking through aquaculture could assist in mitigating its overexploitation. This study is the first to demonstrate the successful artificial breeding and rearing of H. tubulosa, and its consequent potential as a new species for the Mediterranean aquaculture industry. Here we describe the spawning induction, larval development and early juvenile growth in hatchery cultures, aimed at developing a spawning and rearing protocol for this species. The trials were conducted from July to October in both 2014 and 2015. Holothuria tubulosa was induced to spawn by testing four different methods. Thermal stimulation plus thermal shock emerged as the most efficient method to obtain active and healthy gametes. Larval development in H. tubulosa progressed through five stages, reaching the juvenile stage in 27 days. Two different microalgal feeding regimens were tested for larval breeding. Under the best feeding conditions, 7% of the larvae metamorphosed into settled juveniles, adhering to artificial substrates previously conditioned with benthic biofilm. Our results indicate that H. tubulosa shows good performance in hatchery rearing during the larval phases, indicating that this species could be a new candidate for aquaculture in the Mediterranean region, both for production and restocking proposes.

title: Fucosylated chondroitin sulfates from the sea cucumbers Holothuria tubulosa and Holothuria stellati.
abstract: Two polysaccharides HT and HS were isolated from the sea cucumbers Holothuria tubulosa and Holothuria stellati, respectively. Purification of the natural polymers was performed by consecutive ion exchange and gel permeation chromatography. The molar ratio of the monosaccharides and sulfate GlcA:GalNAc:Fuc:SO3Na was determined as 12:14:17:57 for HT and 12:12:16:60 for HS indicating that both polysaccharides are fucosylated chondroitin sulfates. Detailed structural characterization of HT and HS was performed using the 1D and 2D NMR spectroscopic methods. The main chain of HT and HS was shown to consist of alternating 4) b d GlcA (1 and 3) b d GalNAc (1 sequence, where the latter unit was sulfated at O 4 or both at O 4 and O 6. The ratio of GalNAc4S:GalNAc4S6S was determined as 1:4 for HT and 1:4.5 for HS. Three types of sulfated fucosyl branches Fucp2S4S, Fucp3S4S and Fucp4S attached to O 3 of glucuronic acid residues were found in a ratio of 3:3:1 for HT and 2:2:1 for HS.

title: Cytotoxic activity of Holothuria tubulosa (Echinodermata) coelomocytes
abstract: The immune system of marine invertebrates, in particular that of holothurians, still requires further study. Our research showed that coelomocyte cells contained in the coelomic fluid of the sea cucumber, Holothuria tubulosa, are able to lyse, in vitro, red blood cells in rabbits and sheep. A plaque forming assay showed spherule cells to be the effector cells, able to release cytotoxic molecules after xenogenic cell contact. The coelomocyte lysate supernatant, analysed by polyacrylamide gel electrophoresis overlay technique, using rabbit and sheep erythrocytes, showed two different haemolytic protein patterns: one calcium dependent and the other calcium independent. The fractions of each pattern were resolved on a polyacrylamide gel and calcium dependent and independent coelomocyte lysate patterns were compared. HighlightsCoelomocytes of Holothuria tubulosa, are able to lyse, in vitro, red blood cells in rabbits and sheep.Coelomocytes are able to release cytotoxic molecules after xenogenic cell contact causing plaque lysis.Cytotoxic molecules are proteins showing a different lysis pattern in presence or in absence of calcium ions.

title: Multi residue analysis of 36 priority and emerging pollutants in marine echinoderms (Holothuria tubulosa) and marine sediments by solid liquid extraction followed by dispersive solid phase extraction and liquid chromatography tandem mass spectrometry analysis.
abstract: Marine echinoderms are filter feeding invertebrates widely distributed along the coasts, and which are therefore extensively exposed to anthropogenic xenobiotics. They can serve as good sentinels for monitoring a large variety of contaminants in marine ecosystems. In this context, a multi residue analytical method has been validated and applied to Holothuria tubulosa specimens and marine sediments for the determination of 36 organic compounds, which belong to some of the most problematic groups of emerging and priority pollutants (perfluoroalkyl compounds, estrogens, parabens, benzophenones, plasticizers, surfactants, brominated flame retardants and alkylphenols) Lyophilization of samples prior to solvent extraction and clean up of extracts with C18, followed by liquid chromatography tandem mass spectrometry analysis, is proposed. A Box Behnken design was used for optimization of the most influential variables affecting the extraction and clean up steps. For validation, matrix matched calibration and recovery assay were applied. Linearity r2) higher than 99% recoveries between 80% and 114% (except in LAS and NP1EO) RSD (precision) lower than 15% and limits of quantification between 0.03 and 12.5ngg 1 dry weight (d.w. were achieved. The method was applied to nine samples of Holothuria collected along the coast of Granada (Spain) and to marine sediments around the animals. The results demonstrated high bioaccumulation of certain pollutants. A total of 25 out of the 36 studied compounds were quantified, being surfactants, alkylphenols, perfluoroalkyl compounds, triclocarban and parabens the most frequently detected. Nonylphenol was found in the highest concentration (340 and 323ngg 1 d.w. in sediment and Holothuria samples, respectively)

title: Preferential assimilation of seagrass detritus by two coexisting Mediterranean sea cucumbers: Holothuria polii and Holothuria tubulosa
abstract: Holothuria polii and Holothuria tubulosa are two of the most commercially exploited sea cucumbers of the Mediterranean Sea. As deposit feeders, they represent an important component of the benthic community. Hence, knowledge of their feeding behaviour is crucial for understanding their function in terms of benthic ecology and sediment dynamics. Using information obtained from stable isotope analysis, the food selectivity/assimilation, temporal variations in diet and trophic niche of H. polii and H. tubulosa were investigated. Analysis of carbon and nitrogen isotopic ratios in body wall tissue showed a preferential assimilation of seagrass detritus among multiple food sources, with a total contribution to the diet ranging from 63% to 74% The temporal changes in d13C and d15N values followed the seagrass isotopic dynamics with depleted values in winter and enriched values in summer. Additionally, d13C and d15N measurements were used to outline the species' trophic niche width. The two species coexist, showing an overlap on the d13C axis and a partial degree of niche segregation on the d15N axis. Our results provide an overview on the feeding activity of H. polii and H. tubulosa, providing evidence of their crucial role on the seagrass detrital pathways for Mediterranean coastal ecosystems.

title: Seasonal variations of digestive enzymes in sea cucumbers (Holothuria tubulosa, G. 1788) under culture conditions.
abstract: Sea cucumber, Holothuria tubulosa (Gmelin, 1788) is an economically valuable species due to its rich nutrients content that being exported in Turkey. However, culture of this species is difficult due to a lack of knowledge. The main objective of this study is to investigate seasonal activities of main digestive enzymes (protease, lipase, and amylase) for nutritional requirements. In this sense, sea cucumbers were stocked in the glass aquarium and sediment was 10 cm. It was replaced monthly and enriched (1% of the living individual weight) by dried Sargassum sp. Total protease and amylase enzymes have shown higher activity compared to lipase. All three enzyme activities were maximum in the summer and minimum in the winter. In summer, the highest measured total protease, amylase, and lipase activity values were 6.45 0.66, 6.77 0.72, and 2.78 0.32 U/mg per protein, respectively. In winter, the lowest total protease, amylase, and lipase activity values were measured as 2.03 0.16, 1.14 0.14, and 0.12 0.01 U/mg per protein, respectively. As a conclusion of the study, seasonal expression of the main digestive enzymes was strictly dependent on water temperatures and food abundance and also it was ideal to feed this species with food containing high protein and carbohydrate under appropriate temperatures for commercial culture.