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Biopeptides from Sipunculus nudus were reported with good ACE inhibitory activity, and the tripeptide SRP was one with the highest ACE inhibition rate. However, the disadvantage of short half-life limited the development of peptide drugs. Moreover, the distinct mechanism of the peptide inhibiting ACE remained unknown. Thus, in this study, a sustained release formulation of SRP-PLGA-MS was designed and prepared. Its long-lasting antihypertensive effect as well as improvement of vascular pathomorphology was verified in spontaneously hypertensive rat (SHR). In addition, the anti-oxidant activity of SRP in human umbilical vein endothelial cells (HUVECs) was evaluated. The results showed that SRP inhibited the production of ROS and NO, which involve the NADPH oxidase, and Keap1/Nrf2 signaling pathway. This study demonstrated that SRP-PLGA-MS had the potential to develop sustained-release drugs for hypertension treatment.

Enhancing the culture technology of Sipunculus nudus by improving the environmental conditions is a crucial means to address its scarcity. This study aimed to evaluate the effects of different environmental factors on the growth performance, survival, final biomass (FB), and digestive enzyme activity of juvenile S. nudus through three separate single-factor culture experiments. The period set for all experiments was 30 days. In the temperature experiment (five groups were set up: 15 °C, 20 °C, 25 °C, 30 °C, and 35 °C), juvenile S. nudus obtained high growth performance in the water temperature of 25–35 °C, but the survival rate (SR) of the 35 °C group was significantly lower than those of the 25 °C and 30 °C groups (P

The collagen was extracted by acid, enzymolysis and hot water methods respectively from the body wall of Sipunculus nudus, and their physicochemical properties were analyzed. The three collagen extracts were compared respectively by amino acid composition, UV spectroscopy, Fourier infrared spectroscopy and SEM scanning electron microscopy. The effects of the three collagen zynolytes on the growth viability of HaCaT cells were investigated. The results show that the extraction rate of collagen by hot water method is higher than the other two methods, and all three collagens contain the collagen characteristic amino acids Gly, Pro and Hyp. The UV and IR spectrograms show that all three collagens have obvious absorption peaks near 222 nm, and there are absorption peaks of amide A and amide B and characteristic peaks of amide Ⅰ, Ⅱ and Ⅲ, suggesting that all three collagens belong to type I collagen with a three-stranded helical structure. And the results of scanning electron microscopy show that the three-stranded helical structure of collagen extracted by acid method is more complete and maintains the original structure of collagen fibers better than that of enzymatic method and hot water method. The collagen peptides extracts have the ability to significantly increase the viability of normal and UVB-damaged HaCaT cells in the range of 50‒100 µg/mL, indicating that the enzymatic products of collagen of Sipunculus nudus have good potential applications in skin photoaging repair. [ABSTRACT FROM AUTHOR]

Simple Summary: Sipunculus nudus is a species of significant economic importance because of its high nutritional and medicinal value. It is widely distributed along coastlines worldwide, particularly in China, where a comprehensive industry exists encompassing breeding, farming, processing, and sale. Traditionally, S. nudus is cultured on sandy beaches without the need for artificial diets. The organisms rely on nutrients from the surface sediment, including microalgae and other organic matter. These worms inhabit both the intertidal and subtidal zones, enduring varying immersion periods throughout their growth process. As a result, they are exposed to different abiotic factors, such as varying irradiation times, oxygen availability, and others. In our study, we investigated the transcriptomic response of S. nudus across high, middle, and low tidal flats. We analyzed and compared the differential gene expression and relevant metabolic pathways in S. nudus from different habitats. This analysis aimed to shed light on the molecular mechanisms underpinning physiological responses to diverse environments in burrowing species. Interestingly, we observed that the differential gene expression of S. nudus primarily involved metabolic pathways associated with disease and immune responses rather than thermal stress, calcification, and pH regulation. This finding highlights the close relationship between gene expression and S. nudus' unique living habits The peanut worm (Sipunculus nudus) is an important intertidal species worldwide. Species living in the same aquaculture area might suffer different environmental impacts. To increase knowledge of the molecular mechanisms underlying the response to environmental fluctuations, we performed a transcriptome analysis of S. nudus from different intertidal zones using a combination of the SMRT platform and the Illumina sequencing platform. (1) A total of 105,259 unigenes were assembled, and 23,063 unigenes were perfectly annotated. The results of the PacBio Iso-Seq and IIIumina RNA-Seq enriched the genetic database of S. nudus. (2) A total of 830 DEGs were detected in S. nudus from the different groups. In particular, 33 DEGs had differential expression in the top nine KEGG pathways related to pathogens, protein synthesis, and cellular immune response and signaling. The results indicate that S. nudus from different zones experience different environmental stresses. (3) Several DEGs (HSPA1, NFKBIA, eEF1A, etc.) in pathways related to pathogens (influenza A, legionellosis, measles, and toxoplasmosis) had higher expression in groups M and L. HSPA1 was clearly enriched in most of the pathways, followed by NFKBIA. The results show that the peanut worms from the M and L tidal flats might have suffered more severe environmental conditions. (4) Some DEGs (MKP, MRAS, and HSPB1) were upregulated in peanut worms from the H tidal flat, and these DEGs were mainly involved in the MAPK signaling pathway. These results indicate that the MAPK pathway may play a vital role in the immune response of the peanut worm to the effects of different intertidal flats. This study provides a valuable starting point for further studies to elucidate the molecular basis of the response to different environmental stresses in S. nudus. [ABSTRACT FROM AUTHOR]

The tripeptide Leu-Pro-Lys (LPK), derived from the Sipunculus nudus protein, was synthesized and studied to investigate its potential protective effect on bone formation. The effect and mechanism of LPK were analyzed through network pharmacology, bioinformatics, and experimental pharmacology. The study found that LPK at concentrations of 25 µg/mL and 50 µg/mL significantly increased ALP activity and mineralization in C3H10 cells. LPK also increased the expression of COL1A1 and promoted bone formation in zebrafish larvae. Network pharmacology predicted 148 interaction targets between LPK and bone development, and analysis of the protein-protein interaction network identified 13 hub genes, including ESR1, MAPK8, and EGFR, involved in bone development. Through KEGG enrichment pathways analysis, it was determined that LPK promotes bone development by regulating endocrine resistance, the relaxin signaling pathway, and the estrogen signaling pathway. Molecular docking results showed direct interactions between LPK and ESR1, MAPK8, and MAPK14. Additional verification experiments using western blot assay revealed that LPK significantly upregulated the expression of genes related to bone formation, including COL1A1, OPG, RUNX2, ESR1, phosphorylated MAPK14, and phosphorylated MAPK8 in C3H10 cells. These results suggest that LPK promotes bone formation by activating the estrogen/MAPK signaling pathway. [ABSTRACT FROM AUTHOR]

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The present study aimed to investigate the effect of different microwave pre-drying times under hot-air-drying processes on the quality properties and sensory evaluation of Sipunculus nudus (S. nudus). The colour, proximate analysis, amino acid content, fat oxidation, and volatile components of dried S. nudus were determined. Microwave pre-drying could significantly (p < 0.05) increase the drying rate and shorten the drying time. The results of colour, proximate analysis, and amino acid content indicated that microwave pre-drying could improve the quality of the product, resulting in dried S. nudus with less of a loss in nutrients. The samples that underwent microwave pre-drying had a high degree of fatty acid oxidation and low monounsaturated fatty acid content, which facilitated the formation of volatile components. Additionally, the MAD-2 and MAD-3 groups had high relative contents of aldehydes and hydrocarbons, and the FD group had the highest relative content of esters found in the samples. The relative content of ketones and alcohols did not differ significantly between the different drying groups. The finding of this study has important potential for enhancing the quality and aroma of dry S. nudus products with microwave pre-drying during the drying process. [ABSTRACT FROM AUTHOR]

Sipunculus nudus is an important intertidal aquaculture species that can ingest organic matter from the surface sediment and shows a high transportation capacity in sediment. However, little is known about the influence of intertidal aquaculture species on the sediment microbial community and the exchange of microbiota between the intestine and the surrounding sediment. In this study, the microbial communities in the intestine of S. nudus and three kinds of surrounding sediments were analyzed using high-throughput sequencing of the 16S rRNA gene amplicon, and the relationships between different communities were examined. Principal coordinate analysis and ANOSIM/Adonis analysis showed that the microbial communities of worm intestine samples were significantly different from those of surrounding sediments (p < 0.05). Meanwhile, compared with the sediment samples, the microbial α-diversity was significantly lower in the intestinal samples. Although the relative abundances of Proteobacteria and Cyanobacteria were high in all samples, three phyla (Bacteroidetes, Gemmatimonadetes, and Latescibacteria) showed a great difference between the four groups, as the abundances of the three phyla were significantly lower in the intestinal samples. Moreover, several microbial interactions were found between the worm intestine and surrounding sediments. BugBase functional prediction analysis indicated that the oxygen status of the sediment and the intestine was changed by bioturbation by the worm. Therefore, the microenvironment and microbial community in sediment were affected by the activity of S. nudus in the intertidal aquaculture zone. [ABSTRACT FROM AUTHOR]

【Objective】The study aimed to investigate effects of Cu-Fe interaction on growth and physiological function of Sipunculus nudus larvae, so as to provide a reference for further development of efficient artificial compound feed for S. nudus.【Method】A 3×3 fully randomized experiment was adopted. The basic feed was divided into 9 groups with 3 levels (7.8,13.2 and 23.5 mg/kg) of copper (copper methionine) and 3 levels (61.5,120.6 and 243.7 mg/kg) of iron (iron methionine). 8100 S. nudus larvae with average body weight of (16.12±0.26) mg were randomly divided into 9 groups, with 3 replicates per group. 9 kinds of feed were fed to S. nudus for 8 weeks. Differences in the growth and physiological functions of the S. nudus were evaluated.【Result】Adding different amounts of Cu and Fe in the feed significantly influenced weight gain rate, specific growth rate, survival rate, and copper content of S. nudus (P＜0.05,the same as below), but had no significant effect on body composition, catalase (CAT) activity and iron content (P＞0.05). Additive amount of copper and iron in feed had interactive effects on weight gain rate, specific growth rate, survival rate and iron content, but had no interactive effects on the body composition, CAT activity and copper content of S. nudus. The weight gain rate and specific growth rate of S. nudus larvae were the highest when the dietary copper content was 7.8 mg/kg and iron content was 120.6 mg/kg. When copper content was constant, weight gain rate and specific growth rate increased first and then decreased with iron content increasing. When the copper content was 7.8 mg/kg, the survival rate of S. nudus juveniles was mainly affected by iron, and with the increase of iron content, the experimental groups showed a trend of first increasing and then decreasing. CAT activity of juveniles was mainly affected by feed iron content. When the iron content was 61.5 mg/kg, CAT activity of juveniles was significantly lower than other groups.【Conclusion】Interaction effect of copper and iron has a significant impact on growth, survival, and copper content of S. nudus larvae, with no significant effect on body composition, the CAT activity, and iron content. Effect of iron in feed on the growth of S. nudus larvae is greater than that of copper in feed. Taking the weight gain rate as the evaluation standard, the optimum copper and iron contents in feed of S. nudus larvae are 7.8 and 120.3 mg/kg. [ABSTRACT FROM AUTHOR]

IntroductionSipunculus nudus is the most known species in the genus Sipunculus, distributed in tropical and subtropical coastal waters.MethodsPacBio sequencing and Illumina sequencing were combined for whole-genome sequencing of S. nudus. LC-MS/MS analysis was performed for the metabolomics of S. nudus.ResultsHerein, we report a 1.75 Gb complete genome assembly with a contig N50 size of 450 kb of the S. nudus based on a strategy combining third-generation long-read sequencing and Illumina sequencing. A total of 80391 protein-coding genes are annotated in this genome. Furthermore, gene family evolution analysis shows that S. nudus belonged to Mollusca or was close to Mollusca, but distinct with Annelida. Transcriptome analysis indicates the involvement of complex developmental events in larve. KEGG pathway analysis of differentially expressed genes showed that these DEGs were mainly enriched in the pathway of amino acid metabolism, lipid metabolism and transport and catabolism. LC-MS/MS analysis shows that S. nudus was rich in a variety of nutritional and functional components, such as carnitine, free amino acids, unsaturated fatty acids, inosine and methionine sulfoxide. Combined transcriptome with LC-MS/MS analysis, the results showed that gene expression and metabolic level involved in the inosine, arginine and proline biosynthesis of S. nudus during different growth stages were significantly changed.DiscussionOur genome assembly provides an important genome resource and new insight into the relationships of Sipuncula to other spiralian phyla. Meanwhile, transcriptome and LC-MS/MS analysis reveal the systematic gene expression profiles and metabolite components of S. nudus during different growth stages, which provide new insight into the exploration and development of bioactive molecules of S. nudus.

The peanut worm (Sipunculus nudus) is an important economic and ecological fishery resource in China. To determine how S. nudus interacts with its culture environment, in this study, the diversity, composition, and interrelationships of bacterial communities in the intestine, coelomic fluid, and culture environment of S. nudus through high-throughput sequencing using the Illumina HiSeq sequencing platform. Alpha diversity analysis showed that the highest bacterial community richness and diversity were found in the sediments. Species annotation revealed that Proteobacteria dominated in all samples (48.92%–58.36%), and the other dominant phyla were highly variable, indicating a certain independence between the environment and the composition of the bacterial community of S. nudus. The coelomic fluid of S. nudus contained high concentrations of Bacillus and could be a source of potential probiotic bacteria for isolation and culture. Cluster and operational taxonomic unit Venn diagram analyses showed that the bacterial community composition in the intestine was more similar to that in the sediments compared with water. The predicted functional analysis of bacterial communities indicated that the functions of bacterial communities in the different surrounding environment were highly similar and involved in various aspects, such as membrane transport, amino acid metabolism, carbohydrate metabolism, and replication and repair. Our findings have important implications on the establishment of sustainable microecological regulation and management strategies for S. nudus culture and provide a reference for the development and utilization of probiotic bacteria.

W/O/W emulsions can be used to encapsulate both hydrophobic and hydrophilic bioactive as nutritional products. However, studies on protein stabilized gel-like W/O/W emulsions have rarely been reported, compared to the liquid state multiple emulsions. The purpose of this study was to investigate the effect of different oil–water ratios on the stability of W/O/W emulgels fabricated with salt-soluble proteins (SSPs) of Sipunculus nudus. The physical stability, structural characteristics, rheological properties, and encapsulation stability of vitamin C and β-carotene of double emulgels were investigated. The addition of W/O primary emulsion was determined to be 10% after the characterization of the morphology of double emulsion. The results of microstructure and rheological properties showed that the stability of W/O/W emulgels increased with the increasing concentration of SSPs. Additionally, the encapsulation efficiency of vitamin C and β-carotene were more than 87%, and 99%, respectively, and still could maintain around 50% retention of the antioxidant capacity after storage for 28 days at 4 °C. The aforementioned findings demonstrate that stable W/O/W emulgels are a viable option for active ingredients with an improvement in shelf stability and protection of functional activity. [ABSTRACT FROM AUTHOR]

The peanut worm (Sipunculus nudus) is an important intertidal species worldwide. Species living in the same aquaculture area might suffer different environmental impacts. To increase knowledge of the molecular mechanisms underlying the response to environmental fluctuations, we performed a transcriptome analysis of S. nudus from different intertidal zones using a combination of the SMRT platform and the Illumina sequencing platform. (1) A total of 105,259 unigenes were assembled, and 23,063 unigenes were perfectly annotated. The results of the PacBio Iso-Seq and IIIumina RNA-Seq enriched the genetic database of S. nudus. (2) A total of 830 DEGs were detected in S. nudus from the different groups. In particular, 33 DEGs had differential expression in the top nine KEGG pathways related to pathogens, protein synthesis, and cellular immune response and signaling. The results indicate that S. nudus from different zones experience different environmental stresses. (3) Several DEGs (HSPA1, NFKBIA, eEF1A, etc.) in pathways related to pathogens (influenza A, legionellosis, measles, and toxoplasmosis) had higher expression in groups M and L. HSPA1 was clearly enriched in most of the pathways, followed by NFKBIA. The results show that the peanut worms from the M and L tidal flats might have suffered more severe environmental conditions. (4) Some DEGs (MKP, MRAS, and HSPB1) were upregulated in peanut worms from the H tidal flat, and these DEGs were mainly involved in the MAPK signaling pathway. These results indicate that the MAPK pathway may play a vital role in the immune response of the peanut worm to the effects of different intertidal flats. This study provides a valuable starting point for further studies to elucidate the molecular basis of the response to different environmental stresses in S. nudus.

Non-traditional seafood, such as spoon worms (Urechis unicinctus) and peanut worms (Sipunculus nudus), serves as both delicacies and potential solutions to the global food insecurity crisis. Despite being consumed primarily in parts of China, Korea, and Japan, the nutritional values especially the complex fatty acid compositions of these marine worms are difficult to characterize. To overcome this obstacle, we employed covalent adduct chemical ionization (CACI) tandem mass spectrometry for the de novo identification of their unusual polyunsaturated fatty acids (PUFA). Through this method, we identified several PUFA with polymethylene-interrupted (PMI) double bond configurations, including 22:3(7Z,13Z,16Z), a novel PUFA derived from sciadonic acid. U. unicinctus exhibits an exceptionally low n-6/n-3 PUFA ratio of 0.15, making it a potential functional food to counterbalance the n-6/n-3 imbalance in modern diets. S. nudus boasts notably high concentrations (∼3 %, wt/wt) of branched chain fatty acids (BCFA), exceeding typical levels found in dairy products. [Display omitted] • Fatty acids of edible marine worms, spoon worm and peanut worm were characterized. • Double bond positions of unusual fatty acids were identified by GC/CACI-MS/MS. • 22:3(7Z,13Z,16Z) is the first characterized sciadonic acid metabolite. • Spoon worm is potentially a functional food for balancing high dietary n-6/n-3 ratio. • Peanut worm is rich in branched chain fatty acids (BCFA) at about 3 % of total FA. [ABSTRACT FROM AUTHOR]

Tyrosinase inhibitory peptides (TIPs) derived from food resources have attracted immense attention in the food, cosmetic, and pharmaceutical industries owing to their excellent biological safety and ease of absorption. In this study, single-factor experiment and response surface optimization were used to prepare the Sipunculus nudus gelatin enzymatic hydrolysis (SNGH) product. Subsequently, a novel tyrosinase inhibitory peptide was screened out through ultrafiltration classification, biological activity prediction, molecular docking, and molecular dynamics simulation, and its inhibitory mechanism was analyzed. The results revealed that the optimal enzymatic hydrolysis process was: the enzyme addition was 4768.87 U/g, the enzymatic hydrolysis time was 4.72 h, and the enzymatic hydrolysis temperature was 42.76 °C. A total of 287 peptides were detected in the ultrafiltration component Ⅰ (SNGH-Ⅰ) with a high tyrosinase inhibitory activity, and 161 peptides with binding energies < −7.0 kcal/mol were screened out through molecular docking. Subsequently, 91 peptides with a biological activity score >0.3 were obtained after biological activity screening. Finally, 5 possible TIPs were screened out according to their hydrophobicity, peptide score, and molecular weight. Among them, IIAPPERKY, VWDESFKVF, and FAGDDAPRAVFPS exhibited a superior tyrosinase inhibitory activity. Molecular dynamics simulations revealed that IIAPPERKY had better conformational stability and belonged to the group of reversible competitive inhibitors. • SNGH with a high tyrosinase inhibitory activity was prepared from Sipunculus nudus. • A novel stepwise virtual screening method for TIPs was established. • IIAPPERKY exhibited the best tyrosinase inhibitory activity and conformational stability. • The reversible competitive inhibition mechanism between IIAPPERKY and tyrosinase was clarified. [ABSTRACT FROM AUTHOR]

[Objective] This trial was conducted to investigate the effects of Cu-Zn Interaction on growth and physiological function of juvenile peanut worm, Sipunculus nudus Llnnaeus. It provided a reference for the development of efficient and environmentally friendly artificial compound feed for S. nudus. [Method] It was a 3 x 3 two-factor experiment. 8100 S. nudus juveniles with average body weight of (14. 32 ± 0. 21) mg were randomly divided into 9 groups, and the basic feed was divided into three groups. In each group, copper methionine with actual copper content of 5. 0, 10. 0 and 20. 0 mg/kg and zinc methionine with actual zinc content of 20. 0, 40. 0 and 80. 0 mg/kg were added respectively. 9 kinds of feeds (treatment 1 - treatment 9) were fed to S. nudus for 8 weeks. The growth and physiology of different treatments were evaluated. [Result] The interaction of trace elements Cu and Zn in the feed had significant effects on the weight gain rate, specific growth rate, survival rate, AKP, copper and zinc content of the larvae (P <0. 05, the same as below), but had no significant effect on body composition (P >0. 05, the same as below). Moreover, the additive amount of copper and zinc in feed had significant interactive effects on weight gain rate, specific growth rate, survival rate and alkaline phosphatase activity, but had no interactive effects on the body composition, copper content and zinc content of S. nudus. Test group 8 (Cu, 20. 0 mg/kg, Zn; 40. 0 mg/kg) had the highest weight gain rate and specific growth rate. The weight gain rate and specific growth rate of the treatment groups with zinc content of 40. 0 mg/kg (treatment 2, treatment S and treatment 8) were significantly higher than those of the treatment groups with zinc content of 80. 0 mg/kg ( treatment 3, treatment 6 and treatment 9). When the copper content was low (5. 0 mg/kg, 10. 0 mg/kg), the survival rate of S. nudus juveniles is mainly affected by zinc, and with the increase of zinc content, the experimental groups showed a trend of first increasing and then decreasing. When the content of copper increased to 20. 0 mg/kg, the survival rate of S. nudus was mainly affected by copper, but there was no significant difference among the groups. The alkaline phosphatase activity of S. nudus was mainly affected by zinc content in feed. When the zinc level was 20. 0 mg/kg (treatment 1, treatment 4 and treatment 7), the alkaline phosphatase activity of juveniles was significantly lower than other groups. The body contents of Cu and Zn were also affected by dietary Cu level and Zn level, which are positively correlated with the changes of Cu and Zn in feed. [Conclusion] Copper and zinc content in the feed both affect the growth, body composition, distribution and accumulation of elements in the body and alkaline phosphatase activity of S. nudus. The effect of zinc in feed on the growth of S. nudus larvae was greater than that of copper in feed. Taking the weight gain rate as the evaluation standard, the optimum copper and zinc contents in the feed of S. nudus larvae were 20. 0 and 40. 0 mg/kg, respectively, and the corresponding copper methionine addition amount was 117. 6 mg/kg and zinc methionine addition amount was 42. 1 mg/kg. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the effect of different microwave pre-drying times under hot-air-drying processes on the quality properties and sensory evaluation of Sipunculus nudus (S. nudus). The colour, proximate analysis, amino acid content, fat oxidation, and volatile components of dried S. nudus were determined. Microwave pre-drying could significantly (p < 0.05) increase the drying rate and shorten the drying time. The results of colour, proximate analysis, and amino acid content indicated that microwave pre-drying could improve the quality of the product, resulting in dried S. nudus with less of a loss in nutrients. The samples that underwent microwave pre-drying had a high degree of fatty acid oxidation and low monounsaturated fatty acid content, which facilitated the formation of volatile components. Additionally, the MAD-2 and MAD-3 groups had high relative contents of aldehydes and hydrocarbons, and the FD group had the highest relative content of esters found in the samples. The relative content of ketones and alcohols did not differ significantly between the different drying groups. The finding of this study has important potential for enhancing the quality and aroma of dry S. nudus products with microwave pre-drying during the drying process.

Sipunculus nudus is an important intertidal aquaculture species that can ingest organic matter from the surface sediment and shows a high transportation capacity in sediment. However, little is known about the influence of intertidal aquaculture species on the sediment microbial community and the exchange of microbiota between the intestine and the surrounding sediment. In this study, the microbial communities in the intestine of S. nudus and three kinds of surrounding sediments were analyzed using high-throughput sequencing of the 16S rRNA gene amplicon, and the relationships between different communities were examined. Principal coordinate analysis and ANOSIM/Adonis analysis showed that the microbial communities of worm intestine samples were significantly different from those of surrounding sediments (p < 0.05). Meanwhile, compared with the sediment samples, the microbial α-diversity was significantly lower in the intestinal samples. Although the relative abundances of Proteobacteria and Cyanobacteria were high in all samples, three phyla (Bacteroidetes, Gemmatimonadetes, and Latescibacteria) showed a great difference between the four groups, as the abundances of the three phyla were significantly lower in the intestinal samples. Moreover, several microbial interactions were found between the worm intestine and surrounding sediments. BugBase functional prediction analysis indicated that the oxygen status of the sediment and the intestine was changed by bioturbation by the worm. Therefore, the microenvironment and microbial community in sediment were affected by the activity of S. nudus in the intertidal aquaculture zone.

Biopeptides from Sipunculus nudus were reported with good ACE inhibitory activity, and the tripeptide SRP was one with the highest ACE inhibition rate. However, the disadvantage of short half-life limited the development of peptide drugs. Moreover, the distinct mechanism of the peptide inhibiting ACE remained unknown. Thus, in this study, a sustained release formulation of SRP-PLGA-MS was designed and prepared. Its long-lasting antihypertensive effect as well as improvement of vascular pathomorphology was verified in spontaneously hypertensive rat (SHR). In addition, the anti-oxidant activity of SRP in human umbilical vein endothelial cells (HUVECs) was evaluated. The results showed that SRP inhibited the production of ROS and NO, which involve the NADPH oxidase, and Keap1/Nrf2 signaling pathway. This study demonstrated that SRP-PLGA-MS had the potential to develop sustained-release drugs for hypertension treatment., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Huang, Wang, Wang, Deng, Chen, Li, Luo and Lu.)

A novel polysaccharide was extracted from Sipunculus nudus (SNP). The molecular weight (MW) of SNP was determined to be 9223 Da by high‐performance gel permeation chromatography analyses, and the structure of the SNP repeat units was determined to be →3,4‐β‐D‐GlcpNAC (1→ and →4) ‐α‐D‐Glcp (1→ in the ratio of 15:1; →2) ‐α ‐D‐Galp ‐ (1→ as a side chain; and β‐D‐Galp‐(1→ and α‐ D‐Glcp ‐ (1→ as end groups by GC‐MS analysis and NMR assays. The effect of SNP on hepatoma HepG2‐bearing mice was analysed to verify its potential in the clinical treatment of liver cancer. A total of 90 male athymic nu/nu mice were divided into therapeutic and preventive groups and fed with different amounts of SNP. The antitumour effect of SNP on HepG2‐bearing mice and mechanism of such were studied by analysing the tumour size, spleen index, thymus index, immune factors in the blood, tumour apoptosis factors, etc. The results suggest that SNP not only increased the index of immune organs in the body, but also enhanced the secretion of immune factors, including interleukin‐2, interferon gamma and tumour necrosis factor‐alpha in the serum. SNP induced the apoptosis of tumour cells via the mitochondrial apoptosis pathway, which upregulated caspase‐3, caspase‐8, caspase‐9 and BCL2‐associated X, but downregulated B‐cell lymphoma‐2 and vascular endothelial growth factor protein expression. In conclusion, SNP inhibited tumour growth by enhancing immune function and inducing tumour cell apoptosis in HepG2‐bearing mice. Therefore, SNP may be further investigated as a promising candidate for future antitumour drugs. [ABSTRACT FROM AUTHOR]

To form a stable emulsion system, the water-soluble proteins (WSPs) of Sipunculus nudus were prepared as the sole effective stabilizer for the high internal phase emulsion (HIPEs), of which the influence of the WSPs concentration and environmental stability was investigated. The HIPEs were fabricated using a simple one-pot homogenization process (10,000 rpm/min, 3 min) that involved blending the WSPs (0.1, 1, 2, 3, 4, and 5 wt%) with soybean oil (60, 65, 70, 75, 80, 85, and 90%). The microstructure and properties of stable HIPEs were characterized by particle size, ζ-potential, visual observations, optical microscopy, and dynamic rheology property measurements. As the concentration of WSPs increases, the mean particle diameter of HIPEs decreases, on the contrary, the apparent viscosity and storage modulus gradually increase. At a given emulsifier concentration (3 wt%), the stable and gel-like HIPEs were formed at the oil internal phase (ϕ) values of 70–75%, all the pH range in values from 3 to 9, and the ionic strength from 100 to 500 mM. Furthermore, the HIPEs that were stabilized formed a gel-like state that was relatively stable to heat and storage (30 days). And there was a new phenomenon that the destabilized HIPE of the freeze-thaw treatments could still return to a gel-like state again after homogenizing. The study results suggest that the WSPs of S. nudus as a natural emulsifier could be widely used in the food industry.

W/O/W emulsions can be used to encapsulate both hydrophobic and hydrophilic bioactive as nutritional products. However, studies on protein stabilized gel-like W/O/W emulsions have rarely been reported, compared to the liquid state multiple emulsions. The purpose of this study was to investigate the effect of different oil–water ratios on the stability of W/O/W emulgels fabricated with salt-soluble proteins (SSPs) of Sipunculus nudus. The physical stability, structural characteristics, rheological properties, and encapsulation stability of vitamin C and β-carotene of double emulgels were investigated. The addition of W/O primary emulsion was determined to be 10% after the characterization of the morphology of double emulsion. The results of microstructure and rheological properties showed that the stability of W/O/W emulgels increased with the increasing concentration of SSPs. Additionally, the encapsulation efficiency of vitamin C and β-carotene were more than 87%, and 99%, respectively, and still could maintain around 50% retention of the antioxidant capacity after storage for 28 days at 4 °C. The aforementioned findings demonstrate that stable W/O/W emulgels are a viable option for active ingredients with an improvement in shelf stability and protection of functional activity.

The peanut worm (Sipunculus nudus) is an economically important fishery resource in China. To determine how dietary carbohydrate and protein levels affect the growth performance of juvenile S. nudus and identify the mechanisms underlying observed patterns, five isoenergetic and isolipidic diets with different levels of carbohydrate and protein were formulated and fed to juvenile S. nudus; the experimental groups were referred to as EG1, EG2, EG3, EG4, and EG5, respectively. After 90 days of feeding, S. nudus had significantly lower survival rates when fed D5 compared with other diets (P < 0.05), and the highest survival rate was observed in EG2 individuals. The weight gain rate and specific growth rate were significantly higher in EG2 compared with the other groups (P < 0.05). Metabolomic profiling using liquid chromatography–mass spectrometry revealed 83 significantly differential metabolites (POS: 59; NEG: 24), which were identified via an in-house MS2 database. Pathway analysis indicated that the significantly different metabolites were involved in 22 metabolic pathways (POS: 9; NEG: 13), including tyrosine, phenylalanine, and tryptophan biosynthesis; phenylalanine metabolism; D-glutamate and D-glutamine metabolism; proline and arginine metabolism; aspartate, alanine, and glutamate metabolism; and aminoacyl-tRNA biosynthesis. These analyses implied that the biosynthetic capabilities of juvenile S. nudus were greater in the EG2. The results of this research enhance our understanding of the effects of dietary carbohydrate and protein levels on the growth performance of juvenile S. nudus.

In order to make clear the protein compositions of Sipunculus nudus and investigate its immune-related proteins, proteomic analysis was performed on body wall and coelomic fluid of Sipunculus nudus. A total of 1659 proteins were identified, and 539 proteins were differentially expressed in the coelomic fluid compared to those in the body wall, of which 415 proteins were up-regulated while 124 proteins were down-regulated. Gene Ontology (GO) analysis showed that the GO terms involved in the two parts of Sipunculus nudus were similar, with metabolic processes, catalytic activity and cell occupying the top categories of biological process, molecular function and cellular component, respectively. KEGG pathway analysis showed that 49 pathways in body wall and 48 in coelomic fluid were mapped respectively, and these pathways were mainly related to cellular processes, environmental information processing, genetic information processing and metabolism. The COG analysis showed that 757 proteins from body wall and 889 from coelomic fluid were classified into 26 COG categories, respectively. Pfam annotation revealed the mainly immune-related proteins contained in Sipunculus nudus , such as insulin-like growth factor binding protein, catalase, basement membrane proteoglycan, titin. Our research provides the first proteomic information of Sipunculus nudus , which contributes to the study of functional proteins in Sipunculus nudus and is of great significance for the application of Sipunculus nudus in functional foods and medicines. [Display omitted] • Proteomic was used to investigate the biological functions of Sipunculus nudus proteins. • A total of 1373 and 1566 proteins were respectively identified in BW and CF. • The identified proteins were mainly involved in catalytic activity and metabolic processes. • A solid foundation was laid for studying the functional proteins in Sipunculus nudus. [ABSTRACT FROM AUTHOR]

Germinal vesicle (GV) breakdown (GVBD) is an important event in the maturation of oocytes. This process is also a prerequisite for the fertilization of many invertebrates. In Sipunculus nudus, the gonads cannot be observed with the naked eye. Oocytes develop freely in the coelomic fluid and separated easily. Thus, they are a good material for studying invertebrate GVBD. We isolated and obtained samples of oocytes from GV and GVBD phases of S. nudus and constructed two oocyte transcriptomes. Transcriptome analysis identified 14,170 differentially expressed unigenes (DEUs). Gene Ontology (GO) enrichment analysis showed that 69 GO terms were significantly enriched, and 6 GO terms including integral component of membrane (GO: 0016021), nuclearus (GO: 0005634), protein kinase activity (GO: 0004672), protein tyrosine phosphatase activity (GO: 0004725), spindle pole (GO: 0000922) and microtubule organizing center (GO: 0005815) were closely related to GVBD. We identified 31 DEUs associated with the GVBD process including M‐phase inducer phosphatase 2 (CDC25B), 5‐hydroxytryptamine receptor (5‐HTR) and calcium‐transporting ATPase sarcoplasmic/endoplasmic reticulum type (SERCA). The results support the view that hormonal action, calcium regulation, phosphorylation and spindle microtubule action may participate in the process of GVBD. This research presented the development process of S. nudus oocytes and provided valuable materials for the GVBD in other invertebrates. [ABSTRACT FROM AUTHOR]

Larval development, especially settlement and metamorphosis, has a vital influence on commercial culture during the life cycle of marine invertebrates. Sipunculus nudus, a peanut worm, is an important economic aquaculture species. However, information about the mechanism of its larval settlement and metamorphosis is still limited. Transcriptomic analysis was performed to determine the DEGs between the pelagospheric larva and creeping larva of S. nudus. A total of 96,455 unique unigenes were obtained and 46,355 were annotated. Transcriptome analysis revealed 19,352 DEGs, including 9,923 that were upregulated and 9,429 downregulated after settlement and metamorphosis. KEGG pathway enrichment analyses revealed that these DEGs were mainly involved in the Notch signaling pathway, TNF signaling pathway, protein digestion and absorption, thyroid hormone signaling pathway, and ECM–receptor interaction, and so on. Furthermore, the changes in genes related to cytoskeleton and cell adhesion indicated that protein degradation and apoptosis during metamorphosis mediate the loss of larval cilia and ECM remodeling functions in S. nudus metamorphosis. Changes in genes related to signal transduction and nervous system suggested the cessation of larval swimming, which is involved in settlement and metamorphosis. Changes in genes related to ingestion and digestion indicated that dietary shift occurred with metamorphic transition. Changes in some genes related to stress response and immunity indicated that conditioning induced the immune response of peanut worm. The results improve understanding of the physiological traits controlling S. nudus metamorphosis and provide a solid basis for further study.

The sipunculid worm Sipunculus nudus is a widely distributed, commercially important marine mollusc. Oogenesis and sex determination/differentiation are important steps in S. nudus reproduction. However, the molecular mechanisms of oogenesis and sex determination/differentiation in S. nudus are unclear. We successfully generated a high‐quality de novo assembled and annotated transcriptome of oocytes from coelomic fluid (OC), oocytes from nephridium (ON) and spermatozeugmata from coelomic fluid (SC) of S. nudus using the Illumina sequencing platform. There were 17,720 and 17,030 differentially expressed genes (DEGs) in OC vs. ON and OC vs. SC respectively. KEGG pathway analysis showed that the DEGs in these two groups were enriched in ribosome, thyroid hormone synthesis, apelin signalling pathway and cellular senescence. Critical genes that play essential roles in sex determination/differentiation were found, including foxl2, fem‐1, dmrt1, ftz‐f1 and sox9. This may largely contribute to the understanding of the molecular mechanisms of oogenesis and sex determination/differentiation in S. nudus and laid a foundation for further in‐depth studies. [ABSTRACT FROM AUTHOR]

[Display omitted] • A glycoprotein (SGP1) was isolated from Sipunculus nudus for the first time. • SGP1 is a protein-dominate glycoprotein with O-glycosidic bonds containing 92.8% protein. • SGP1 was a predominantly β-sheet glycoprotein. • SGP1 exhibited strong immune-enhancing activity by promoting proliferation, phagocytosis and the secretions of NO, IL-1β, TNF-α and IL-6 on RAW264.7 cells. • SGP1 exerts immune-enhancing activity via NF-κB signaling pathway. Sipunculus nudus , an edible marine invertebrate, has long been used as traditional Chinese medicine in folk remedies. In order to assess the immunoregulatory activity of glycoproteins in Sipunculus nudus and conduct a structure–activity relationship, a glycoprotein (SGP1) with molecular mass of 9.26 kDa was purified from Sipunculus nudus , and its chemical structure as well as immune-enhancing activity was investigated in this study. Structure analysis revealed that SGP1, a protein-dominate glycoprotein with O-glycosidic bonds, contained 92.8 % protein and 3.1 % saccharide. GC–MS result indicated that the saccharide moieties of SGP1 basically consisted of lyxose (Lyx), xylose (Xyl) as well as glucose (Glu) at a molar proportion of 0.87:4.16:1.36. The fourier transform infrared specoscopy (FT-IR) result proved that SGP1 have a typical characteristic of glycoprotein. Besides, circular dichroism (CD) result showed that SGP1 contained 4.1 % α-helix, 42.5 % β-sheet, 21.4 % β-turn, and 32.0 % random coil, indicating it's mainly a β-sheet glycoprotein. The amino acid sequence of SGP1 shared a similarity to the Myohemerythrin (sp|Q5K473|HEMTM) with protein sequence coverage of 28.3 %. Moreover, the activity evaluation results showed that SGP1 exhibited significant immune-enhancing activity to the RAW 264.7 macrophages by promoting macrophages proliferation, enhancing phagocytic capacity, and simultaneously stimulating the secretions of nitric oxide (NO), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) via NF-κB pathways. In this study, SGP1 as a novel glycoprotein had an obvious immune-enhancing activity to macrophages, and thus could be applied in the functional foods as a potential immunopotentiator for the hypoimmune population. [ABSTRACT FROM AUTHOR]

Peanut worm, Sipunculus nudus is a cosmopolitan species found in inter-tidal sands. In this article, based on the samples collected from the Beibu Gulf, China, a mitochondrial DNA sequence by Illumina high throughput sequencing, was carried out on muscle and determined the complete mitogenome. This mitogenome of peanut worm is 15,331 base pairs in length (Accession number: MN481531) and comprises of 37 genes as in the typical mitochondrial gene arrangement of Sipunculus. Moreover, the phylogenetic analysis shows that our sample is a novel type in China and has a distantly genetic relationship with the known populations in South China Sea. This mitogenome will serve as the foundation for the molecular genetic studies of peanut worm.

Marine collagen peptides have high potential in promoting skin wound healing. This study aimed to investigate wound healing activity of collagen peptides derived from Sipunculus nudus (SNCP). The effects of SNCP on promoting healing were studied through a whole cortex wound model in mice. Results showed that SNCP consisted of peptides with a molecular weight less than 5 kDa accounted for 81.95%, rich in Gly and Arg. SNCP possessed outstanding capacity to induce human umbilical vein endothelial cells (HUVEC), human immortalized keratinocytes (HaCaT) and human skin fibroblasts (HSF) cells proliferation and migration in vitro. In vivo, SNCP could markedly improve the healing rate and shorten the scab removal time, possessing a scar-free healing effect. Compared with the negative control group, the expression level of tumor necrosis factor-α, interleukin-1β and transforming growth factor-β1 (TGF-β1) in the SNCP group was significantly down-regulated at 7 days post-wounding (p < 0.01). Moreover, the mRNA level of mothers against decapentaplegic homolog 7 (Smad7) in SNCP group was up-regulated (p < 0.01); in contrast, type II TGF-β receptors, collagen I and α-smooth muscle actin were significantly down-regulated at 28 days (p < 0.01). These results indicate that SNCP possessed excellent activity of accelerating wound healing and inhibiting scar formation, and its mechanism was closely related to reducing inflammation, improving collagen deposition and recombination and blockade of the TGF-β/Smads signal pathway. Therefore, SNCP may have promising clinical applications in skin wound repair and scar inhibition.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objectives] This study was conducted to optimize the extraction process of Sipunculus nudus polysaccharide and study the antioxidant activity of S. nudus polysaccharide. [Methods] S. nudus polysaccharide was extracted by ultrasonic microwave assisted method, during which univariate factors including solid-liquid ratio, time, temperature, ultrasonic power, microwave power were investigated, to select optimal extracting conditions, which were also verified by an response surface optimization experiment (an four-factor three-level test); and the antioxidant activity of S. nudus polysaccharide was studied by determining its DP-PH radical scavenging capacity. [Results] Through univariate factor investigation and response surface optimization test, it was found that the response surface results were consistent with univariate results. The optimized conditions were as follows: solid-liquid ratio at 1:15, ultrasonic temperature at 60 °C, ultrasonic power of 360 W and microwave power of 200 W, and the predicted polysaccharide extracting amount was 4.35 mg/g. Under the optimized extracting conditions, the average extracting amount of S. nudus polysaccharide was 4.38 mg/g, which is close to the theoretical predicted value (4.35 mg/g). And the results of this study also showed that different concentrations of polysaccharide solutions have different scavenging effects on DPPH free radical. At the polysaccharide concentration of 0.16 mg/ml, the maximum value of DPPH radical scavenging rate was 7.22%, indicating that polysaccharide has certain antioxidant capacity. [Conclusions] This method is a new trial with satisfactory results. [ABSTRACT FROM AUTHOR]

[Objectives] This study was conducted to optimize experimental conditions for extraction of polysaccharides from Sipunculus nudus. % Methods] With the Sipunculus nudus from Sanya as the experimental material, S. nudus polysaccharide was extracted by ultrasonic microwave asisted method, during which univariate factors including solid-liquid ratio, time, temperature, ultrasonic power, microwave power were investigated, to select optimal extracting conditions, which were also demonstrated and optimized by variance and response surface analysis. The optimized conditions were adopted to carry out a test, in which the absorbance of S. nudus polysaccharide was measured with an ultraviolet and visible spectrophotometer, followed by the calculation of the extracting amount of polysaccharide, and precision test and recovery test were also carried out to verify the experimental method. [ Results] The standard solutions were determined at the maximum absorption wavelength of 486 nm, and the regression equation was A - 0. 267 7C + 0.001 8, R2 - 0. 999 8. Solid-liquid ratio, time, temperature, ultrasonic power and microwave power were investigated by univariate analysis and then optimized by response surface method as follows: solid-liquid ratio at 1:20 ( gmf), time of 35 min, temperature at 50 П, ultrasonic power at 420W and microwave power at 300 W, under which the measured extracting amount of S. nudus polysaccharide wa 1.37 mg g. The RSD was 0. 985 % in precision experiment. In the repeatability test, the extracting amounts of polysaccharide were 1.41, 1.43 and 1.38 mg g for three parallel tests, respectively, with a RSD of 1.140 %. The recovery test obtained following results: for group a ( added with glucose standard )$ the recovery of S. nudus polysaccharide was in the range of 100.3% -101.4%, RSD -0.03% ; and for group b ( not added with glucose standard) : the recovery of S. nudus polysaccharide was in the range of 99. 7% - 100. 3%, RSD - 0.02% . [ Conclusions] The research method is stable and reliable. This study provides data basis and reference for follow-up study on S. nudus. [ABSTRACT FROM AUTHOR]

[Objectives] rrhis study was conducted to optimize the extraction process of Sipunculus nudus polysaccharide. [Methods] 5. nudus polysaccharide was extracted by ultrasonic water extraction, with the marine S. nudus as a raw material from Sanya City, Hainan Province, by single factor variable method, to find the optimal extraction conditions including ultrasonic power, solid-liquid ratio, ultrasonic extraction temperature, ultrasonic extraction time, ultrasonic extraction times and lye concentration. The absorbance of the polysaccharide was determined by an ultraviolet spectrophotometer, and polysaccharide yield were calculated. The antioxidant activity of scavenging hydroxyl and DPPH radicals was measured at different concentrations. [Results] The optimal extraction conditions for S. nudus polysaccharide were as follows: solid-liquid ratio at 1:11 mg/ml, extraction temperature at 60 t, three times of ultrasonic extraction, ultrasonic power of 960 W, extraction time of 1.5 h, and lye concentration of 5 %, under which the polysaccharide yield was 3.21%. The scavenging rates of hydroxyl radical and DPPH radical were 12.58% at the concentration of 0.20 mg/ml. Moreover, the scavenging rates increased significantly with the increase of concentration. [Conclusions] This method is a new trial with satisfactory results. [ABSTRACT FROM AUTHOR]

The peanut worm Sipunculus nudus is an economic important species in the fishery and aquaculture in Indo-West Pacific. However, it is a species complex consisting of cryptic species, which can be difficult to identify based on morphology. Here, we report the complete mitochondrial genome sequence of S. nudus from Beibu Bay. The mitogenome has 15,375 base pairs and made up of total of 38 genes (13 protein-coding, 23 transfer RNAs, and two ribosomal RNAs), and a putative control region. There were 5948 mutations sites between Chinese and French populations. This study adds a distinct mitogenome of S. nudus, and will provide useful genetic information for future genetic variation identification and genetic diversity evaluation of this economic valuable marine benthic invertebrate.

Three angiotensin I converting enzyme (ACE) inhibition peptides were isolated from sandworm Sipunculus nudus protein hydrolysate prepared using protamex. Consecutive purification methods, including size exclusion chromatography and reverse-phase high performance liquid chromatography (RP-HPLC), were used to isolate the ACE inhibition peptides. The amino acid sequences of the peptides were identified as Ile-Asn-Asp, Val-Glu-Pro-Gly and Leu-Ala-Asp-Glu-Phe. The IC values of the purified peptides for ACE inhibition activity were 34.72 μmol L, 20.55 μmol L and 22.77 μmol L, respectively. These results suggested that S. nudus proteins contain specific peptides that can be released by enzymatic hydrolysis. This study may provide an experimental basis for further systematic research, rational development and clinical utilization of sandworm resources. [ABSTRACT FROM AUTHOR]

Sipunculus nudus is an important economic species because of its high nutritional and medicinal values. The exploitation and utilization of S. nudus primarily occur in the coastal regions of the Beibu Gulf. However, wild resource of S. nudus is rapidly decreasing because of the overexploitation, which has led to considerable developments of artificial breeding techniques. The cultivation scale of S. nudus has increased in response to successful artificial breeding; however, methods for culturing S. nudus in tidal flats or ponds require further study. Most studies have focused on the breeding, nutrition, medical value and ecological impact of these worms. Studies on the distribution, sediment requirements, nutrition characteristics, breeding techniques and aquaculture ecology of this species are summarized in this paper to promote the development of the aquaculture industry for S. nudus. The high biomass of S. nudus in the Beibu Gulf is positively correlated with the sediment characteristics and water quality of the region. The production of peanut worm has improved to some extent through culturing; however, the nutrient value and ecological environment problems have been observed, which reflect the over exploitation of trace elements and the sediment. These problems will worsen unless they are resolved, and the release of organic materials, nitrogen and phosphorus during harvesting impacts the coastal environment. Moreover, genetic erosion is a potential risk for larvae in artificial breeding programs in tidal flats. Therefore, culturing and collecting methods should be improved and the wild resource conservation should be implemented to promote the sustainable development of the peanut worm. [ABSTRACT FROM AUTHOR]

Sipunculus nudus, an old marine species, has great potential for use as functional seafood due to its various bioactivities. Its potential antithrombotic activity pushed us to isolate the bio-active components bio-guided by tracking fibrinolytic activity. As a result, a novel protease named as SK (the kinase obtained from S. nudus) was obtained, which possessed a molecular weight of 28,003.67 Da and 15 N-terminal amino acid sequences of PFPVPDPFVWDTSFQ. SK exerted inhibitory effects on thrombus formation through improving the coagulation system with dose-effect relationship within a certain range. Furthermore, in most cases SK got obviously better effect than that of urokinase. With the help of untargeted mass spectrometry-based metabolomics profiling, arachidonic acid, sphingolipid, and nicotinate and nicotinamide mechanism pathways were found to be important pathways. They revealed that the effect mechanism of SK on common carotid arterial thrombosis induced by FeCl3 was achieved by inhibiting vessel contraction, platelet aggregation, adhesion, and release, correcting endothelial cell dysfunction and retarding process of thrombus formation. This study demonstrated SK was a promising thrombolytic agent on the basis of its comprehensive activities on thrombosis, and it should get further exploitation and utilization.

The tripeptide Leu-Pro-Lys (LPK), derived from the Sipunculus nudus protein, was synthesized and studied to investigate its potential protective effect on bone formation. The effect and mechanism of LPK were analyzed through network pharmacology, bioinformatics, and experimental pharmacology. The study found that LPK at concentrations of 25 μg/mL and 50 μg/mL significantly increased ALP activity and mineralization in C3H10 cells. LPK also increased the expression of COL1A1 and promoted bone formation in zebrafish larvae. Network pharmacology predicted 148 interaction targets between LPK and bone development, and analysis of the protein-protein interaction network identified 13 hub genes, including ESR1, MAPK8, and EGFR, involved in bone development. Through KEGG enrichment pathways analysis, it was determined that LPK promotes bone development by regulating endocrine resistance, the relaxin signaling pathway, and the estrogen signaling pathway. Molecular docking results showed direct interactions between LPK and ESR1, MAPK8, and MAPK14. Additional verification experiments using western blot assay revealed that LPK significantly upregulated the expression of genes related to bone formation, including COL1A1, OPG, RUNX2, ESR1, phosphorylated MAPK14, and phosphorylated MAPK8 in C3H10 cells. These results suggest that LPK promotes bone formation by activating the estrogen/MAPK signaling pathway., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Wang, Feng, Chen, Liang, Hou, Ouyang, Yu, Ye, Cai, Qi, Wu and Luo.)

Many polysaccharides have biological activities and have been investigated for their antitumor effects. In this study, we investigated the anti-tumor activity and anti-virus activity of SNP—the water-soluble polysaccharides extracted from Sipunculus nudus on Hepg2.2.15. Flow cytometry analysis demonstrated that SNP induced dose-dependent cell apoptosis on Hepg2.2.15. Real-time PCR and Western Blot analysis showed that SNP down-regulated the synthesis of HBsAg, HBV-DNA and enhanced the expression of pro-apoptosis proteins TNF-α, caspase-3, and Bax, while decreasing the expression of the anti-apoptosis proteins survivin, Bcl-2, and VEGF. These results suggested that SNP suppressed cell viability of Hepg2.2.15 and that could be a novel anti-tumor and anti-HBV agent. [ABSTRACT FROM AUTHOR]

To evaluate the nutritional and functional value of Sipunculus nudus, a rapid, simple and sensitive analytical method was developed using ultra-high performance liquid chromatography coupled with a triple quadrupole mass detection in multiple-reaction monitoring mode for the simultaneous quantitative determination of 25 free amino acids and 16 nucleosides and nucleobases in S. nudus within 20 min, which was confirmed to be reproducible and accurate. The limits of detection (LODs) and quantification (LOQs) were between 0.003-0.229 μg/mL and 0.008-0.763 μg/mL for the 41 analytes, respectively. The established method was applied to analyze 19 batches of S. nudus samples from four habitats with two different processing methods. The results showed that S. nudus contained a variety of free amino acids, nucleosides and nucleobases in sufficient quantity and reasonable proportion. They also demonstrated that the contents of these compounds in different parts of S. nudus were significantly discriminating, which were in the order: (highest) coelomic fluid > body wall > intestine (lowest). The method is simple and accurate, and could serve as a technical support for establishing quality control of S. nudus and other functional seafoods. Moreover, the research results also laid foundation for further exploitation and development of S. nudus. [ABSTRACT FROM AUTHOR]

Active nonvolatile taste active compounds—including free amino acids, flavor 5ʹ-nucleotides, lactic acid, succinic acid, and four kinds of inorganic ions in dried Sha-chong (Sipunculus nudus)—were analyzed. The results were then used to calculate taste activity values (TAVs) and equivalent umami concentration (EUC) to evaluate their potential contributions to depth of flavor. Our results showed that the total free amino acid content of dried Sha-chong was 56.62 mg/g; glycine, arginine, and alanine as the major free amino acids, accounting for more than 76% of the total free amino acids; 5ʹ-adenosine monophosphate (AMP) and 5ʹ-inosine monophosphate (IMP) were the main flavor 5ʹ-nucleotides (128.8 and 121.0 mg/100 g); guanosine monophosphate (GMP) was present in a small amount, only 14.6 mg/100 g. Eight amino acids—especially Gly, Arg, and Ala,—three flavor 5ʹ-nucleotides, succinic acid, sodium, potassium, phosphate, and chloride ions were of high TAV greater than 1. The EUC of dried Sha-chong was 49.12 g MSG/100 g, which meant that the dried Sha-chong has a strong umami taste and is suitable for use as umami condiment. [ABSTRACT FROM AUTHOR]

Sipunculus nudus Linnaeus polysaccharide (SNP) was purified from S. nudus L. via NaOH extraction, trichloroacetic acid deproteination, DEAE-cellulose 52 and Sephacryl S-300 chromatography. The monosaccharide analysis and molecular weight was detected with HPLC. FT-IR, 1 H spectrum and 13 C NMR spectrum were performed to detect the chemical characteristics. The antioxidant activity was assayed in vitro. The radiation protection effects were detected on mice. The results showed that SNP was composed of mannose, rhamnose, galacturonic acid, glucose, arabinose and fucose, and the average molecular weight was 680 kDa. Above the concentration of 10 mg/mL, SNP showed powerful scavenging activity on hydroxyl radical. In the animals irradiated with a 7.5 Gy γ-rays, the 90 mg/kg and the 270 mg/kg SNP groups survived significantly longer than the radiation control group. In the animals irradiated with a 4.0 Gy γ-rays, SNP showed significant protection effect. The contents of DNA in bone marrow cells were significantly increased by SNP treatment, and the micronucleus rates of 30 mg/kg and 270 mg/kg SNP groups were decrease significantly compared to the radiation control group . These findings suggest that SNP possesses marked antioxidant and bone marrow damage protection capacity which play important roles in the prevention of radiation damage. [ABSTRACT FROM AUTHOR]