Integrated microbiomics and metabolomics analysis reveals the influence of gut microbiota on the growth and metabolism of sea cucumber seedlings.

AIMS: This study explores the impact of gut microbiota on body metabolites and the growth rate of sea cucumber seedlings. METHODS AND RESULTS: A comprehensive analysis using metabolomics and microbiomics was conducted to ascertain the gut microbiota and body metabolites in sea cucumber seedlings exhibiting varying growth rates. Distinct changes in the intestinal flora were observed in correlation with different growth rates of sea cucumber seedlings. The microbial communities of faster-growing seedlings exhibited greater diversity and evenness of taxa. For example, the abundance of genera Rhodococcus, Woeseia, Lysobacter, Desulfuromonadia_Sva1033, and Flavobacteriaceae_NS5_marine_group was more than 24 times higher in the fast-growing group compared to the slow-growing group. Metabolomics analysis revealed an association between high growth rates of cucumber seedlings and discrepancies in metabolites, such as amino acids, lipids, and carbohydrates. Isorenieratene, possibly synthesized by Rhodococcus, was more than 2.5 times more abundant in the fast-growing group than the slow-growing group. Slow-growing seedlings showed considerable enrichment of environmental pollutants, such as antibiotics and drugs, while their colonies were devoid of bacteria capable of degrading such pollutants. In addition, significant differences were observed between groups in the biosynthesis of amino acids, metabolism of arginine and proline, biosynthesis of unsaturated fatty acids, and metabolism of linoleic acid. Moreover, significant correlations between the microbial genera and sea cucumber metabolites were identified through correlation analysis. CONCLUSIONS: Significant differences exist in the gut microbiota and metabolite composition among seedlings with varying growth rates. Microbes residing in the gut have the potential to influence the growth of seedlings through modulation of their metabolism.

Neiella holothuriorum sp. nov., isolated from the gut of a sea cucumber Apostichopus japonicus.

A Gram-stain negative, aerobic, rod-shaped bacterium, designated 126T, was isolated from the intestinal content of a sea cucumber, Apostichopus japonicus, in China. Strain 126T was found to grow optimally at 25-28 °C and pH 7.5-8.0 in marine 2216 E medium, with tolerance of 1-7% (w/v) NaCl. Strain 126T is motile by means of one to several polar flagella. The dominant fatty acids of strain 126T were identified as C16:1 ω7c/C16:1 ω6c (29.5%), C18:1 ω7c/C18:1 ω6c (19.8%) and C16:0 (16.7%). The respiratory quinone was found to be Q-8. The polar lipid profile was found to be mainly composed of phosphatidylglycerol and phosphatidylethanolamine. The total length of the draft genome is approximately 4.2 × 106 bp, encoding 3655 genes and 3576 coding sequences. The G + C content of the genomic DNA is 48.0%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 126T belongs to the genus Neiella and is closely related to Neiella marina J221T (96.5%). Genomic comparisons of 126T to N. marina J221T revealed that they had similar genome size, G + C content and complement of clusters of orthologous groups. However, average nucleotide identity and digital DNA-DNA hybridization values between strains126T and N. marina J221T was 75.5% and 19.7%, which could distinguish the strains. On the basis of these phenotypic and genotypic data, strain 126T is concluded to represent a novel species, for which the name Neiella holothuriorum sp. nov. is proposed. The type strain is 126T (= GDMCC 1.2530T = KCTC 82829T).

Characterization and Caco-2 Cell Transport Assay of Chito-Oligosaccharides Nano-Liposomes Based on Layer-by-Layer Coated.

Chito-oligosaccharides (COSs) were encapsulated by the film-ultrasonic method into three nano-liposomes, which were uncoated liposomes (COSs-Lip), chitosan-coated liposomes (CH-COSs-Lip), and sodium alginate (SA)/chitosan (CH)-coated liposomes (SA/CH-COSs-Lip). The physicochemical and structural properties, as well as the stability and digestive characteristics, of all three nano-liposomes were assessed in the current study. Thereafter, the characteristics of intestinal absorption and transport of nano-liposomes were investigated by the Caco-2 cell monolayer. All nano-liposomes showed a smaller-sized distribution with a higher encapsulation efficiency. The ζ-potential, Z-average diameter (Dz), and polydispersity index (PDI) demonstrated that the stability of the SA/CH-COSs-Lip had much better stability than COSs-Lip and CH-COSs-Lip. In addition, the transport of the nano-liposomes via the Caco-2 cell monolayer indicated a higher transmembrane transport capacity. In summary, the chitosan and sodium alginate could serve as potential delivery systems for COSs to fortify functional foods and medicines.

Production of the angiotensin I converting enzyme inhibitory peptides and isolation of four novel peptides from jellyfish (Rhopilema esculentum) protein hydrolysate.

BACKGROUND: Angiotensin I converting enzyme (ACE) plays an important role in regulating blood pressure in the human body. ACE inhibitory peptides derived from food proteins could exert antihypertensive effects without side effects. Jellyfish (Rhopilema esculentum) is an important fishery resource suitable for production of ACE inhibitory peptides. The objective of this study was to optimize the hydrolysis conditions for production of protein hydrolysate from R. esculentum (RPH) with ACE inhibitory activity, and to isolate and identify the ACE inhibitory peptides from RPH. RESULTS: Rhopilema esculentum protein was hydrolyzed with Compound proteinase AQ to produce protein hydrolysate with ACE inhibitory activity, and the hydrolysis conditions were optimized using response surface methodology. The optimum parameters for producing peptides with the highest ACE inhibitory activity were as follows: hydrolysis time 3.90 h, hydrolysis temperature 58 °C, enzyme:substrate ratio 2.8% and pH 7.60. Under these conditions, the ACE inhibitory rate reached 32.21%. In addition, four novel ACE inhibitory peptides were isolated, and their amino acids sequences were identified as Val-Gly-Pro-Tyr, Phe-Thr-Tyr-Val-Pro-Gly, Phe-Thr-Tyr-Val-Pro-Gly-Ala and Phe-Gln-Ala-Val-Trp-Ala-Gly, respectively. The IC50 value of the purified peptides for ACE inhibitory activity was 8.40, 23.42, 21.15 and 19.11 µmol L(-1) . CONCLUSION: These results indicate that the protein hydrolysate prepared from R. esculentum might be a commercial competitive source of ACE inhibitory ingredients to be used in functional foods. © 2015 Society of Chemical Industry.

Structural characterization of a P-selectin and EGFR dual-targeting fucoidan from Sargassum fusiforme.

In this study, we obtained fucoidans SFP, SHP, STP, and FVP from Sargassum fusiforme, Sargassum horneri, Sargassumthunbergii, and Fucus vesiculosus, respectively. Chitosan/fucoidan nanoparticles (Cs/F NPs) were prepared using the fucoidans mentioned above. SFP NPs and SHP NPs showed strong binding abilities to P-selectin and epithelial growth factor receptor (EGFR). Given the yields from the alga, SFP was first selected to explore the structural characteristics of the P-selectin and EGFR dual-targeting fucoidan. SFP had an estimated molecular weight of 739 kDa and was mainly composed of galactose (26.57%, mol%) and fucose (66.81%), with minor amounts of mannose (2.54%), glucosamine (0.42%), and glucose (3.66%). Galactose and fucose accounted for thevast majority. Further investigation, including methylation analysis, one- and two-dimensional nuclear magnetic resonance, and mass spectroscopy, was performed to reveal the fine structure of SFP. The results indicated that SFP mainly consisted of â†’ 3)-α-l-Fucp-(1→, →4)-α-l-Fucp-(1→, →3,4)-α-l-Fucp-(1→, →3)-ß-d-Galp-(1→, and minor â†’ 6)-ß-d-Galp-(1→, partially sulfated at the C-4 of â†’ 3)-α-l-Fucp-(1→, C-3 of â†’ 4)-α-l-Fucp-(1→, C-3 of â†’ 6)-ß-d-Galp-(1→, and C-6 of â†’ 3)-ß-d-Galp-(1 â†’ . Sulfated fuco- and galactofuco-segments formed the branches.

[The study of the secondary metabolites from fungus Paecilomyces sp].

OBJECTIVE: To get active secondary metabolites from the fungus Paecilomyces sp.. METHODS: The strain Paecilomyces sp. was further grown in solid-substrate fermentation cultures, the metabolites were got by application of different separation techniques, such as silica gel, Sephadex LH-20 column chromatography, and reversed-phase high performance liquid chromatography. Their structures were identified by comprehensive spectroscopic methods. RESULTS: Four compounds were isolated and identified as Cerebroside C (1), Cerebroside D (2), 2-Hydroxybenzyl alcohol (3), 2-(4-Hydroxyphenyl) ethanol. CONCLUSION: Four compounds are isolated from Paecilomyces sp. for the first time.

Hypolipidemic effect of soluble dietary fibers prepared from Asparagus officinalis and their effects on the modulation of intestinal microbiota.

The soluble dietary fiber from Asparagus officinalis (ASDF) was successively prepared using enzymolysis combined with spray-drying technology. High-performance liquid chromatography analysis showed that ASDF contained two polysaccharide fractions with the average molecular weight of 2.77 × 105 and 6.44 × 103 Da, and was composed of mannose, rhamnose, galacturonic acid, glucose, galactose, and arabinose with a molecular ratio of 19.93:1.02:1.94:32.17:1.00:1.91, respectively. ASDF showed potential in vitro antioxidant activities. The oral administration of ASDF significantly reduced the levels of total cholesterol, triglyceride, and low-density lipoprotein cholesterol in HD-induced mice serum. Furthermore, 16S rRNA gene sequencing analysis showed that ASDF significantly affected the composition of intestinal microbiota, especially reducing the Firmicutes/Bacteroidotetes ratio and the relative abundances of Desulfobacterota, Proteobacteria, Actinobacteriota and increasing that of Muribaculaceae, Bacteroides, and Alloprevotella. These results demonstrated that the intake of ASDF could regulate intestinal microbiota and serum lipid levels in hyperlipidemic conditions.

A fucoidan from Sargassum fusiforme with novel structure and its regulatory effects on intestinal microbiota in high-fat diet-fed mice.

A fucoidan SFP, having novel structure, was extracted from Sargassum fusiforme. It had a molecular weight of 703 kDa and was composed of fucose and galactose with the ratio of 73.16:26.84 (mol%). Structural analyses showed that it mainly consisted of 1,3-, 1,4-, 1,3,4-linked-α-l-Fucp and 1,3-, 1,6-linked-ß-d-Galp, with partial sulfation at C-4, C-3 of fucose units and C-6, C-3 of galactose units. The branches consisted of sulfated fucosyl and galactofucosyl oligosaccharides. The regulatory effects of SFP on the intestinal microbiota in high-fat diet-fed mice were investigated. The high-dosage SFP exhibited good hypolipidemic effects, especially in regulating the high-densitylipoproteincholesterol, non-esterified fatty acid levels and lipase activity. It also significantly decreased the ratio of phyla Firmicutes/Bacteroidetes (P < 0.05). Besides, SFP had certain effects on the richness and diversity of intestinal microbiota. Therefore, SFP exhibited novel structure and certain beneficial effects on the disorder of intestinal microbiota in high-fat diet-fed mice.

[Study on the second metabolisms from fungus HS-1 Epicoccum spp. from the sea cucumber in Yellow Sea].

OBJECTIVE: To get active metabolites from the microbes associated with sea cucumber. METHODS: Fungus was isolated from the sea cucumber, and the species was identified by molecular biology, and then was cultivated in GYP medium, and the metabolites were got by chromatography. Their structures were identified by comprehensive spectroscopic methods. RESULTS: Fungus HS-1 Epicocum sp. was isolated from the sea cucumber in Weihai, Yellow Sea. Four compounds were got as 5-methyl-6-hydroxy-8-methyoxy-3-methylisochroman (1), 8-hydroxy-3-methylisochroman-1-one (2), peroxy-ergosterol (3) and succinic acid (4). CONCLUSION: Fungus HS-1 Epicocum spp. is first isolated from the sea cucumber sample, this research provides new idea for further development of sea cucumber.

Hot water pretreatment-induced significant metabolite changes in the sea cucumber Apostichopus japonicus.

Hot water pretreatment of sea cucumbers potentially changes nutritional benefits. This study aimed to quantify hot water pretreatment-induced changes in metabolite profiles of sea cucumber body walls. ICP-OES, GC-MS, and LC-MS analyses of untreated- (UT-BW), hot water-treated body walls (HW-BW) of Apostichopus japonicus, and the hot water extract (HW-E) determined significant losses of minerals (25-50% w/w), protein (~11% w/w), carbohydrate (33% w/w), saponins (~41% w/w), and spermidine (100%), a potential antipsychotic from hot water-treated samples. Multivariate comparisons of HW-BW with UT-BW and HW-BW with HW-E showed increases in amino acids and fatty acids, suggesting hot water-induced degradation or transformation or easier extraction of protein, lipid or other components. Presence of 80 to 88.5% of compounds in the HW-E and lower DHA, EPA and glycerophospholipids levels in HW-BW suggested extraction of these metabolites. These data indicate that novel processing technologies are required to preserve the full nutritional benefits of sea cucumbers.

[The secondary metabolites of the mangrove endophytic fungi ZZF13 and Guignardia sp. 4382 from the South China Sea].

OBJECTIVE: The secondary metabolites of the fungus ZZF13 isolated from the leaves of the mangrove sample Kandelia candel in Zhanjiang and Guignardia sp. 4382 isolated from bark of Kandelia candel (endophyte) of Mai Po, Hong Kong were studied. METHODS: The compounds were isolated by siliga gel, and their structures were identified by IR, MS and NMR. RESULTS: Four compounds were isolated from the culture of this strain. Their structures were identified as Bacillpsporin C (1), 5-carboxymellein (2), 5-methylmellein (3) and 1-(2,6-dihydroxyphenyl) butanone (4). CONCLUSION: The compounds 2 - 4 are isolated from the Guignardia sp. of Marine fungi for the first time.

Three new oleanane-type triterpenoid saponins from the seeds of Celosia cristata L.

Phytochemical investigation of the 1-butanol soluble fraction of 60% ethanol extract of the seeds of Celosia cristata L. led to the identification of three new oleanane-type triterpenoid saponins. Using 1D and 2D NMR experiment methods, ESI-MS analysis and acid hydrolysis, their structures were identified as 3-O-[ß-D-xylopyranosyl-(1 â†’ 3)-ß-D-glucuronopyranosyl]-2ß-hydroxy-oleanolic acid-28-O-ß-D-glucopyranoside (1), 3-O-[ß-D-xylopyranosyl-(1 â†’ 3)-ß-D-glucuronopyranosyl]-2ß, 23-dihydroxy-oleanolic acid-28-O-ß-D-glucopyranoside (2) and 3-O-[ß-D-glucopyranosyl-(1 â†’ 4)-ß-D-glucopyranosyl]-2-hydroxyl-medicagenic acid-28-O-ß-D-glucopyranosyide (3), respectively.

Cellulase-assisted extraction, characterization, and bioactivity of polysaccharides from Polygonatum odoratum.

Cellulase-assisted extraction of polysaccharides from Polygonatum odoratum (CPP) was optimized by response surface methodology (RSM) and the extracted CPP's preliminary chemical characteristics, as well as antioxidant and immunomodulatory activities were also investigated. The optimal extraction parameters comprised an extraction temperature of 58.21 °C, an extraction time of 3.18 h, pH value of 5.8, and cellulase amount of 6.0%. Under these conditions, the relative yield was 15.76%, higher than the yield achieved with hot water extracted polysaccharide (HPP). Chemical composition analysis demonstrated that CPP and HPP consisted of mannose, glucosamine, rhamnose, glucose, galactose, and arabinose with a molecular ratio of 7.80:1.08:1.63:65.93:3.58:1.00 and 11.22:0.23:0.23:17.59:2.73:9.10, respectively. The molecular weight distribution of CPP was lower and more homogeneous compared with HPP. CPP exhibited stronger antioxidant activities than HPP, including DPPH radical scavenging activity and reducing power. Both CPP and HPP could significantly promote the proliferation and neutral red phagocytosis of RAW 264.7 macrophage cells in vitro. These results indicate that the cellulase-assisted extraction method influenced the physicochemical characteristics, and consequently, the functional activities of polysaccharides, suggesting the cellulose-assisted method may be a viable option for extraction polysaccharides from P. odoratum.

Angiotensin converting enzyme (ACE) inhibitory, antihypertensive and antihyperlipidaemic activities of protein hydrolysates from Rhopilema esculentum.

Angiotensin-converting enzyme (ACE) inhibitory, antihypertensive and antihyperlipidaemic activities of protein hydrolysates (RPH) from the jellyfish Rhopilema esculentum were investigated. R. esculentum was hydrolysed sequentially with pepsin and papain, and then the hydrolysate was ultrafiltered with a 2000 Da cut-off membrane. It was found that RPH contained high levels of Gly, Glu, Pro, Asp and Ala, having potential ACE inhibitory activity in vitro with an IC(50) of 1.28 mg/ml. It was also found that systolic blood pressure was reduced markedly in spontaneously hypertensive rats after single and chronic oral administration of RPH, indicating that RPH had an antihypertensive effect. In addition, oral administration of RPH decreased total serum cholesterol and triglyceride, and increased high-density lipoprotein cholesterol in rats fed with high-fat diet. These results indicate that RPH may prove to be a promising functional food for the prevention and treatment of hypertension and hyperlipidaemia.

Antioxidant and antihyperlipidemic activities of polysaccharides from sea cucumber Apostichopus japonicus.

Polysaccharides (AJP) were prepared from Apostichopus japonicus by protease hydrolysis method. Antioxidant activity in vitro and antihyperlipidemic activity in vivo was investigated. Chemical composition analysis indicated that AJP was mainly composed of glucosamine, galactosamine, glucuronic acid, mannose, glucose, galactose and fucose, with an average molecular weight of about 36.2 kDa. The antioxidant capacities of AJP were, respectively, evaluated by the assays of scavenging DPPH, hydroxyl and superoxide radicals, and reducing power in vitro. It showed potent free radical scavenging activities and reducing power. Serum total cholesterol (TC), triglyceride (TG) and low-density lipoprotein (LDL-C) decreased significantly and high-density lipoprotein cholesterol (HDL-C) increased significantly after treatment of hyperlipidemic Wistar rats with AJP. These results suggest that AJP may prove to be a potential candidate of the natural antioxidants as a therapeutic agent for hyperlipidemia.

Isolation and characterization of a new benzofuran from the fungus Alternaria sp. (HS-3) associated with a sea cucumber.

A new compound, 4-acetyl-5-hydroxy-3, 6, 7-trimethylbenzofuran-2(3H)-one (1), together with two known compounds, 2-carboxy-3-(2-hydroxypropanyl) phenol (2) and 5-methyl- 6-hydroxy-8-methyoxy-3-methylisochroman (3) were isolated from the fungus Alternaria sp. (HS-3) associated with a sea cucumber from the Yellow Sea in China. Their structures were elucidated by spectral methods.

Antioxidant activity of chito-oligosaccharides on pancreatic islet cells in streptozotocin-induced diabetes in rats.

AIM: To investigate the antioxidant activity of chito-oligosaccharides (COSs) on pancreatic islet cells in diabetic rats induced by streptozotocin. METHODS: The antioxidant effect of COSs on pancreatic islet cells was detected under optical microscopy and with colorimetric assay and gel electrophoresis. The activities of glutathione peroxidase and superoxide dismutase, total antioxidant capacity, and content of malondialdehyde in serum and tissue slices of pancreas were examined after 60 d to determine the effect of COSs in streptozotocin-induced diabetes in rats. RESULTS: COSs can prohibit the apoptosis of pancreatic islet cells. All concentrations of COSs can improve the capability of total antioxidant capacity and activity of superoxide dismutase and decrease the content of malondialdehyde drastically. Morphological investigation in the pancreas showed that COSs have resulted in the reduction of islets, loss of pancreatic cells, and nuclear pyknosis of pancreatic cells. CONCLUSION: COSs possess various biological activities and can be used in the treatment of diabetes mellitus.