Red Sea Cucumber Research Articles

Effect of food on specific dynamic action (SDA) of green and red types of sea cucumber (Apostichopus japonicus Selenka)

Specific dynamic action (SDA), the energy expended on all physiological processes that is associated with meal digestion and absorption, is strongly affected by food type. Effects of formulated diet (FMD), macroalgae (ALG) and sea mud (SMD) diets on the postprandial metabolic response of the green type and the red type of sea cucumber (Apostichopus japonicus) were studied in order to understand their feeding physiology. Food offered to A. japonicus was different in protein, lipid content and energy but not in meal mass. SDA of A. japonicus resulted in a 1.3–2.7 folds of increase in oxygen consumption that can persist for up to 4.8–31.7 h after digesting three different diets. In a given type of sea cucumber, the magnitude of SDA was the highest when fed with FMD, medium with ALG, and the lowest with SMD, which is probably due to the differences in diet components and protein contents. The red type sea cucumber showed greater SDA magnitude than the green type with each diet treatment, which might result from the difference in factorial scope between the two types of sea cucumber. However, the smallest magnitude or even no difference was observed between the two types of A. japonicus in SMD group, perhaps owing to the poor nutrition and digestion of sea mud.

홍해삼(Stichopus japonicus) 치삼의 성장 및 면역증강을 위한 면역증강사료첨가제의 개발

The juvenile red variant of the sea cucumber Stichopus japonicus is distributed worldwide. It is a valuable food source in Korea, China, and Japan. Major issues in farming the juvenile red variant sea cucumber include growth rates and disease resistance. In recent years, studies have focused on feed additives to enhance immune system and health. In this study, we used a common diet (CD), a nutritional diet (ND; mixed nutritional supplements), and an immunity diet (ID; mixed probiotics, spirulina, and levan) and compared the growth rates and immunity of juvenile red variant sea cucumbers fed the experimental diets for 12 weeks. The growth and survival rates in the ID group were significantly increased (P>0.05). This suggests that the feed additives positively influenced immunity and growth in the ID group. However, the immune activity was exhibit a stabilizing effect, and further investigation of immune effects is required.

Size and abundance of Red Striped sea cucumber Thelenota rubralineata in Cagayancillo, Palawan, Philippines

On 22 April 2015 at around 14:00 – 15:00 hours, six divers/researchers composed of representatives from Tubbataha Management Office, World Wildlife Fund for Nature and Western Philippines University explored the reef walls in Bandila, Cagayancillo, Palawan,Philippines. At a depth of about 15 m, two Thelenota rubralineata (Figure 1) measuring 35 and 40 cm were encountered on a small patch of sand. Subsequently, three individuals measuring 40, 38 and 30 cm, respectively were noted on an adjoining patch of sand and rock at 20 m deep. Thelenota rubralineata (family Stichopodidae) with its striking patterns of crimson line on white background is considered one of the most beautiful macrobenthic reef invertebrates. They are widely distributed in the Indo-Pacific Region but considered a rare species (Lane 1999; Kinch 2005). They are seldom encountered in the reefs of Palawan (Jontila et al. 2014; Dolorosa 2015), possibly because of the nature and depths of their habitats, and effects of harvesting. Since its description in 1991 (Massin and Lane 1991), not much has been detailed about its biology (Conand et al. 2013). According to Kerr (2006) the species can reach a maximum length of 50 cm. An individual measuring 50 cm in length was also reported in Tubbataha Reefs Natural Park (TRNP), but the density was very low (0.19 ind.ha-1) compared with other sea cucumber species (Dolorosa 2015). The estimated area covered during the dive was about 6,000 m2 (600 x 10 m) thus suggesting a density of about 8 individuals per hectare. However, the sighting was only in one out of seven dives covering a total area of at least 9,0000 m2. An average density of at least one individual per 220 m2 (or 45.45 ind.ha-1) was reported only in Bunaken Marine Reserves, Sulawesi (Lane 1999) but densities in other areas are less than 1 individual per hectare (Conand et al. 2013). Together with many other sea cucumber species, Thelenota rubralineata is exploited in the Philippines (Schoppe 2000; Jontila et al.2014) and in its known distribution range (Lane 1999; Kinch 2005; Purcell etal. 2012). Sea cucumbers are prone to overharvesting (Schoppe 2000; Hasan 2005; Hasan and Abd El-Rady 2012; Purcell et al. 2012, 2013) and this could affect the people mainly dependent on their fishery. Monitoring the natural recovery of populations in marine protected areas and studies involving breeding and restocking of this species is suggested. Given its beauty, the tourism value of the species is important and could exceed its dried market value, thus there is a need to protect the species, at least at the local level.

Effects of water depth and substrate color on the growth and body color of the red sea cucumber, Apostichopus japonicus

Three color variants of the sea cucumber, Apostichopus japonicus are recognized, the red one is highly valued in the market. When the red variant is cultured in ponds in China, its body color changes from red to celadon in 3–6 months. The effects of water depth and substrate color on the growth and body color of this animal were investigated. Juveniles of red A. japonicus were cultured in cages suspended at a range of water depths (20, 50, 100, 150 and 200 cm). The specific growth rate of red sea cucumbers was significantly higher in animals cultured at deeper water layers compared with those grown at shallowers. Body weights were greatest for sea cucumbers cultured at a depth of 150 cm and their survival rates were highest at a depth of 200 cm. A scale to evaluate the color of red sea cucumbers (R value) was developed using a Pantone standard color card. All stocked animals in the 9-month trial retained a red color, however the red body color was much more intense in sea cucumbers cultured at shallower depths, while animals suspended in deeper layers became pale. In a separate trial, A. japonicus were cultured in suspended cages with seven different colored substrates. Substrate color had a significant effect on the growth and body-color of red A. japonicus. The yield were greatest for A. japonicus cultured on a yellow substrate, followed by green > white > orange > red > black and blue. All sea cucumbers in the 7-month trial retained a red color, although the red was most intense (highest R value) in animals cultured on a blue substrate and pale (lowest R value) for animals cultured on a green substrate.

Harvesters׳ perspectives on the management of British Columbia׳s giant red sea cucumber fishery

In recent decades, sea cucumber fisheries have rapidly expanded worldwide to meet rising demand in Asian markets. Catch trends have often followed a boom-and-bust trajectory and skyrocketing sea cucumber value has often spurred fishery development that outpaced adequate biological research for informed stock assessment. Currently, the dive fishery for Giant red sea cucumber (Parastichopus californicus) in British Columbia, Canada is considered moderately exploited. However, basic population parameters such as recruitment and mortality rates are still largely unknown, creating important sources of uncertainty in the fishery׳s stock assessment model. This study presents the results of an interview-based survey of experienced commercial harvesters׳ (1) perceptions of local trends in sea cucumber abundance, size, and fishing effort (CPUE), and (2) perceptions of management efficacy. The majority of harvesters perceived abundance (14/20) and CPUE (15/20) to have declined over their careers, and half of the harvesters reported decreased sea cucumber size. The harvesters most commonly cited overfishing as the most pressing problem facing the fishery (13/20), and the majority felt that Fisheries and Oceans Canada (DFO) needed to lower licence and/or area quotas to avoid further declines. Despite many knowledge gaps in the fishery, almost all harvesters (16/20) perceived that they are not adequately consulted and their concerns are not adequately considered by DFO. These results suggest a disjoint between DFO forecasts and perceived local sea cucumber trends, and highlight that the fishery may lack a resource-rights framework with adequate checks to decouple fishing pressure from increasing global market value and demand. Maintaining the long-term health of the BC sea cucumber fishery may depend on working more closely with harvesters to inform future management decisions and, ideally, moving towards a harvester-owned-and-operated licencing system that can better integrate the feedback that comes from attachment to place.

Genetic differences between wild and hatchery populations of red sea cucumber (Stichopus japonicus) inferred from microsatellite markers: implications for production and stocking programs design

Red sea cucumber Stichopus japonicus is the most important and valuable commercial sea cucumber species in Korea. Its farming and stock enhancement started in the early 2000s and is still rapid expansion in Korea. Therefore, the analyses of genetic status of wild and hatchery populations are necessary to maintain the genetic diversity of this valuable marine resource. In this study, possible genetic similarity and differences between the wild population and hatchery population in Jeju, Korea were accessed using multiplex assays with eight highly polymorphic microsatellite loci. High levels of polymorphism were observed between the two populations. A total of 93 different alleles were found. Although a considerable loss of unique alleles and relatively high inbreeding coefficient value were observed in the hatchery samples, no statistically significant reductions were found in heterozygosity or allelic diversity in the hatchery population, compared with the wild population. However, significant genetic heterogeneity was found between two populations. These results suggest that genetic drift has probably promoted differentiation between populations, and stocking intensity in wild populations may correlate with loss of genetic integrity. Therefore, the sustainable exploitation plans of the fishery resource should be developed by applying basic genetic principles combined with molecular monitoring. This genetic baseline information of Korean red sea cucumber has important implications for designing of genetically sustainable restocking programs and more efficient conservation management guidelines for these valuable genetic materials.

Behavior of the Galapagos fishing fleet and its consequences for the design of spatial management alternatives for the red spiny lobster fishery

The two most profitable fisheries in the Galapagos Islands, red spiny lobster (Panulirus penicillatus) and sea cucumber (Isostichopus fuscus), are facing steep declines in abundance and may be on the verge of collapse. This state of affairs has emerged in part because of command and control fisheries policies that neglected the importance of the behavior of the fishing fleet itself. Here we attempt to describe and explain the factors influencing the fishing behavior of the Galapagos red spiny lobster fishing fleet. We estimated a set of econometric models based on a random utility maximization process to forecast how changes in the immediate circumstances (economic, biological, climatic and oceanographic) impact voluntary fishing choices via the personal costs and benefits of various decisions. We focused on the factors that affect not only the decision to participate in fishing but also the decision of where to fish. We then use these models to determine the revenue elasticities for each fishing zone and to analyze the overall response of the Galapagos fleet to hypothetical closures of fishing zones. Our results provide some empirical benchmarks from which it is possible to identify in advance problems related to the spatial management of the red spiny lobster fishery and their potential solutions. For example, we found that fisherman from San Cristobal Island have a strong preference for fishing sites on Floreana Island, which is geographically closer to Santa Cruz Island. This could lead to conflicts between the San Cristobal and Santa Cruz fishing fleets if rights-based fishery management were implemented. We expect that our analysis will be valuable to policy makers when designing new types of management plans for Galapagos fisheries.

Comparison of oxygen consumption rate and ammonia-N excretion rate between green type and red typeApostichopus japonicus

Experimental ecological method was used to compare the oxygen consumption rate and ammoniaN excretion rate betw een red type and green type Apostichopus japonicus,aiming at the investigation on the optimum environmental range for reproduction and culture conditioning of this species. Sea cucumbers w ere taken to the laboratory,acclimated for 10 d at five temperatures( 7,12,17,22 and 27 ℃),six salinities( 23,26,29,32,35 and 38) and five light colors( w hite,red,yellow,green and blue). The uniform size individuals w ere separately sampled from the red and green A. Japonicus. The results show ed that: 1) Oxygen consumption rate( OCR) and ammonia-N excretion rate( AER) w ere positively correlative to the temperature for both types A. japonicus. Under the test temperatures( 7- 27 ℃),the increasing OCR values of the red and green types sea cucumbers covered the range of 7. 58- 25. 94 and 13. 12- 25. 61 μg /( g · h)respectively. OCR for the red type w as significantly higher than the green one at 7 ℃ and 27 ℃,how ever,it significantly low er than the green one at 22 ℃( P 0. 05). 2) The AER for red type w as positively correlative to the temperature,w hile for the green one AER reached the maximum at 17 ℃ and then it declined w ith the increasing of temperature. The AER for the red and green types w ere 0. 62- 2. 57 and 0. 90- 2. 22 μg /( g·h),respectively. AER for the red type w as significantly higher than that of the green one at7 ℃,and it significantly low er than the green one at 27 ℃. 3) At test salinities of 26 to 38,both of the OCR and AER show ed a shape of ‘M 'w ith the increasing of salinity. OCR for the red and green ones w ere in range of 15. 72 to 21. 32 μg /( g·h),14. 83 to 21. 80 μg /( g ·h),and AER w as 1. 47 to 2. 83 μg /( g ·h),1. 40 to 2. 00 μg /( g·h),respectively. OCR of red type w as significantly low er than that of the green one in range of salinity 23 to 32( P 0. 05),w hereas AER only w as significantly higher at salinity of 29betw een the tw o types A. japonicus( P 0. 05). 4) Under different light color treatments OCR values for the red type and the green type covered range of 14. 33- 21. 37 and 15. 73- 21. 59 μg /( g · h),and AER covered 4. 00- 8. 86 and 6. 38- 8. 22 μg /( g · h),respectively. The OCR and AER w ere significantly different under w hite light treatment betw een the tw o types A. japonicus( P 0. 05). This study demonstrated that the red type A. japonicus could tolerate higher temperature and w as sensitive to low er temperature,w hile the green type show ed an opposite tendency; The optimum salinity range for tw o types A. japonicus w as 29-32; The green type may have broader light spectrum compared w ith the red type A. japonicus. Above all,the adaptability of the red and the green type A. japonicus to experimental conditions w ere w ell consistent w ith their natural habitats.

Chemical composition of the giant red sea cucumber, Parastichopus californicus, commercially harvested in Alaska

Giant red sea cucumbers, Parastichopus californicus, are commercially harvested in the U.S. Pacific Northwest; however, the nutritional and chemical properties of its edible muscle bands and body wall have not been fully elucidated. In particular are the fatty acid profiles of P. californicus tissues, which have not been documented. Sea cucumbers were delivered live and muscle bands and body wall freeze dried, vacuum packed, and stored at –30°C until analyzed. Proximate composition of freeze-dried tissues varied greatly with muscle bands being composed of 68% protein, 12% ash, 9% carbohydrate, and 5% lipids, while the body wall was composed of 47% protein, 26% ash, 15% carbohydrate, and 8% lipids. The hydroxyproline, proline, and glycine contents of the body wall were much higher than those in muscle bands, consistent with the larger amount of connective tissue. Calcium, magnesium, sodium, and iron contents were higher in the body wall than those in muscle bands, whereas the opposite was observed for zinc content. Total long-chain n-3 fatty acid contents were 19% and 32% of total fatty acids in body wall and muscle bands, respectively. Muscle bands had higher content of eicosapentaenoic acid (20:5n-3) than body wall at 22.6% and 12.3%, respectively. High content of arachidonic acid (20:4n-6) was recorded in both body wall (7.1%) and muscle bands (9.9%). Overall, the fatty acid profiles of body wall and muscle bands of P. californicus resemble those described for other species; however, the distribution and occurrence of certain fatty acids is unique to P. californicus, being representative of the fatty acid composition of temperate-polar marine organisms. The chemical characterization of freeze-dried edible tissues from P. californicus demonstrated that these products have valuable nutritional properties. The body wall, a food product of lower market value than muscle bands, could be better utilized for nutraceutical and pharmaceutical applications.

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.

Comparative study on nutrient composition and growth of green and red sea cucumber,Apostichopus japonicus(Selenka, 1867), under the same culture conditions

Comparative study on nutrient composition and growth of green and red sea cucumber,<i>A</i><i>postichopus japonicus</i>(Selenka, 1867), under the same culture conditions

Pepsin-solubilised collagen (PSC) from Red Sea cucumber (Stichopus japonicus) regulates cell cycle and the fibronectin synthesis in HaCaT cell migration

Pepsin-solubilised collagen (PSC) from Red Sea cucumber (Stichopus japonicus) was studied with respect to its wound-healing effects on a human keratinocyte (HaCaT) cell line. Disaggregated collagen fibres were treated with 0.1M NaOH for 24h and digested with pepsin for 72h to reach maximum yield of 26.6%. The results of an in vitro wound-healing test showed that migration of HaCaT cells was 1.5-fold faster on PSC-coated plates than on untreated plates. The migration rate of sea cucumber PSC was similar to that of rat PSC, but five times higher than that of bovine gelatin. HaCaT cells grown on PSC-coated plates revealed increased fibronectin synthesis (6-fold and 3-fold compared to gelatin and rat PSC, respectively). Additionally, sea cucumber PSCs induced HaCaT cell proliferation by decreasing the G1 phase by 5% and maintaining a larger population (8%) of cells in mitosis. Collagen from Red Sea cucumber might be useful as an alternative to mammalian collagen in the nutraceutical and pharmaceutical industries.

Biological effects of various solvent fractions derived from Jeju Island red sea cucumber (Stichopus japonicas)

Red variants of S. Japonicas show unique ecological characteristics and are indigenous to Jeju Island in South Korea. Various biological activities of red sea cucumber extracts (RSCEs) were evaluated. In comparison with positive controls, anti-oxidant activity of RSCEs was very low. In HL-60 and HT-29 cells, chloroform and ethyl acetate (EtOAc) fractions showed higher than 80 and 60% growth inhibition, respectively. Nuclear condensation and increased pro-apoptotic signaling revealed that RSCEs triggered apoptosis. EtOAc fractions also showed strong anti-inflammatory effects at sub-lethal concentrations in lipolysaccharide-stimulated RAW264.7 cells and suppressed more than 90% of nitric oxide (NO) and prostaglandin 2 productions at 50 μg/mL by inhibiting inducible NO synthase and cydooxygenase-2. Water-soluble fractions showed good antibacterial effects against Staphylococcus aureus and Staphylococcus epidermidis.

Effect of salinity on growth and energy budget of red and green colour variant sea cucumberApostichopus japonicus(Selenca)

Sea cucumber, Apostichopus japonicus (Selenca), tolerates salinity fluctuations inhabiting intertide zone. This study deals with growth, food intake, food conversion and the bioenergetic responses of the red variant (wet weight of 2.60 ± 0.11g) and green variant (wet weight of 2.56 ± 0.08 g) A. japonicus to different salinities of 22, 26, 30, 34, and 38 psu at 16.5 ± 0.5°C. The results showed that salinity had a significant effect on specific growth rate (SGR) of both green and red variants A. japonicus (P 0.05). Values of adaptable salinity scope for green and red variants sea cucumber survival are 18.5~39 psu and 20.9~38.6 psu respectively. The average energy budget formula of sea cucumber at 30 psu was: 100C = 6G +42F +3U+49R (C, energy ingested; G, energy for growth; F, energy loss as faeces; U, energy used for ammonia excretion; R, energy loss for respiration). The sea cucumber had maximum energy ingested (C) and highest proportion of energy for growth (G) at 30 psu, and then decreased when salinity is above or below this salinity. Both red and green variants of A. japonicus deposited for growth were very low, and the energy loss in faeces and energy for respiration accounted for the majority of assimilation energy. The result clearly showed that the optimum condition for farming green and red variants A. japonicus, both with respect growth and energy allocation, is the salinity scope of 26 ~ 30 psu.

Optimization of Hydrolysis Conditions for the Production of the Angiotensin-I Converting Enzyme Inhibitory Peptides from Sea Cucumber Collagen Hydrolysates

The effects of different hydrolysis conditions on the angiotensin-I converting enzyme (ACE) inhibitory properties of giant red sea cucumber (Parastichopus californicus) collagen hydrolysates were investigated. Optimal conditions predicted by central composite rotatable design (CCDR) modeling for producing ACE inhibitory peptides were found to be 54.9°C, 1.76 h and an enzyme to substrate (E/S) ratio of 0.064. Compared with experiments performed under these optimal conditions, the predicted degree of hydrolysis (DH) and ACE inhibitory activities had error rates of 3 to 6%. Under optimum conditions, the molecular weights of collagen hydrolysates were less than 6.5 kDa. Lineweaver-Burk plots suggest that the collagen hydrolysates acted as competitive inhibitors with an inhibition constant (Ki) value of 0.706 mg/mL.

Use of Pacific OysterCrassostrea gigas(Thunberg, 1793) Shell to Collect Wild Juvenile Sea CucumberParastichopus californicus(Stimpson, 1857)

Although sea cucumbers have been successfully cultivated for restocking, very little is known about wild juvenile sea cucumber (JSC) settlement, recruitment, growth, population dynamics, natural mortality, or their ecological role. For fishery managers to develop management practices that accelerate the recovery of overfished areas and to increase the survival rate of restocked organisms, they need an understanding of spatial and temporal trends in JSC distribution and abundance, as well as cost-effective recruitment monitoring techniques. We show that wild juvenile giant red sea cucumber (Parastichopus californiens) can be collected using a commercial oyster cultch bag filled with Pacific oyster (Crassostrea gigas) shell. From the collection results, it is clear that location, depth, and substrate influence the settlement of JSC. Using JSC collectors will enable further identification of trends in sea cucumber recruitment and will give a better understanding of the distribution and behavior of JSC in various environments.

Amino acid composition and functional properties of giant red sea cucumber (Parastichopus californicus) collagen hydrolysates

Giant red sea cucumber (Parastichopus californicus) is an under-utilized species due to its high tendency to autolysis. The aim of this study was to evaluate the functional properties of collagen hydrolysates from this species. The degree of hydrolysis (DH), amino acid composition, SDS-PAGE, emulsion activity index (EAI), emulsion stability index (ESI), foam expansion (FE), and foam stability (FS) of hydrolysates were investigated. The effects of pH on the EAI, ESI FE and FS of hydrolysates were also investigated. The results indicated that the β and α1 chains of the collagen were effectively hydrolyzed by trypsin at 50°c with an Enzyme/Substrate (E/S) ration of 1:20 (w:w). The DH of collagen was up to 17.3% after 3 h hydrolysis with trypsin. The hydrolysates had a molecular weight distribution of 1.1–17 kDa, and were abundant in glycine (Gly), proline (Pro), glutamic acid (Glu), alanine (Ala) and hydroxyproline (Hyp) residues. The hydrolysates were fractionated into three fractions ( 10 kDa), and the fraction of 3–10 kDa exhibited a higher EAI value than the fraction of > 10 kDa (P 10 kDa had higher FE and FS values than other fractions (P 10 kDa showed higher FE value, respectively. They are hoped to be utilized as functional ingredients in food and nutraceutical industries.

Effect of collagen purified from red sea cucumber (Stichopus japonicus) in Jeju on growth of human fibroblast cells

Pepsin-solubilized collagen (PSC) from red sea cucumber (Stichopus japanicus) was purified to study the effects on human fibroblast cell line. PSC(1.92g) was purified out of 100g of sea cucumber body. SDS-PAGE analysis of purified PSC indicated that collagen from sea cucumber was α1ß type collagen type I. The PSC did not have cytotoxicity on various cell Iines. The treatment of PSC to human fibroblast cells increase the mRNA of MMP-1 gene not that of MMP-2 compared to untreated control. However, in case of MMP-2, mRNA is decreased upon PSC treatment. Treatment of PSC suppressed the synthesis of collagen in vivo. Unlike to fibroblast, keratinocyte reduced the MMP-2 production upon PSC treatment.

Purification and Characterization of Pepsin-Solubilized Collagen from Skin and Connective Tissue of Giant Red Sea Cucumber (Parastichopus californicus)

Pepsin-solubilized collagen (PSC) was extracted from giant red sea cucumbers ( Parastichopus californicus ) and characterized for denaturation temperature (T(d)), maximum transition temperature (T(m)), enzyme-digested peptide maps, and gel-forming capability. SDS-PAGE showed that PSCs from giant red sea cucumber skin and connective tissue were both type I collagens, consisting of three alpha(1) chains of approximately 138 kDa each. The amino acid composition and peptide maps of PSCs digested by V8 protease were different from those of calf skin type I collagen. The T(d) and T(m) are 18.5 and 33.2 degrees C, respectively, for skin PSC and are 17.9 and 32.7 degrees C, respectively, for connective tissue PSC. Both skin and connective tissue PSCs exhibited good gel-forming capability at pH 6.5 and at an ionic strength of 300 mM salt (NaCl). Collagen isolated from giant red sea cucumbers might be used as an alternative to mammalian collagen in the food and pharmaceutical industries.

Genetic variability analysis in five populations of the sea cucumber Stichopus (Apostichopus) japonicus from China, Russia, South Korea and Japan as revealed by microsatellite markers

AbstractThe genetic structure of populations of the sea cucumber Stichopus (Apostichopus) japonicus was investigated using 10 microsatellite markers. In all, 152 individuals from five natural populations were collected from Aomori, Japan (JA and JR), Yosu, South Korea (KY), Dalian, China (CD) and Vladivostock, Russia (RV). A total of 145 alleles were found at 10 loci. The number of alleles per locus ranged from 9 at PSC03 to 20 at SCZ06, with an average of 14.5. Average Ho and He ranged from 0.260 (JR) to 0.434 (JA) and from 0.654 (RV) to 0.778 (KY), respectively. No significant differences at A, Ho and He were found, indicating similar genetic diversity in the five populations. A single allele was found at the PSC05 locus in the RV population. Of the 50 loci, 42 significantly deviated from Hardy–Weinberg equilibrium, all showing heterozygote deficiency. The genetic distances were all relatively great, ranging from 0.497 (between JA and KY) to 1.029 (between KY and JR). This suggests the five populations are genetically distinct. Cluster analysis indicated that JA, KY and CD form one branch and RV and JR another in the UPGMA tree. A hypothesis is proposed for the evolution of the Japanese red sea cucumbers and the genetic relationship among the populations.