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Excessive reactive oxygen species (ROS) may lead to oxidative damage and metabolic disorder. The pathogenesis of human bowel inflammation is closely related to oxidative damage of intestinal epithelial cells caused by ROS. This study aimed to explore the high-value utilization of the byproducts of sea cucumber in antioxidant food for colitis prevention. The technology of protease hydrolysis combined with Cordyceps militaris fermentation was used to obtain fermented sea cucumber viscera protease hydrolysates (FSVHs). The results revealed that FSVH could enhance antioxidant capacity and alleviate oxidative damage and apoptosis by activating the Nrf2/HO-1 pathway and triggering the self-protection immune mechanisms. Moreover, the FSVH supplementation could upregulate antioxidant-related metabolic pathways of Caco-2 cells such as glutathione metabolism, confirming the enhanced antioxidant capacity of damaged cells. In summary, FSVH could exert protective effects on Caco-2 cells in response to oxidative damage, providing a promising prospect for sea cucumber resource utilization and colitis prevention. [ABSTRACT FROM AUTHOR]

Salinity is an important environmental factor in microbial ecology for affecting the microbial communities in diverse environments. Understanding the salinity adaptation mechanisms of a microbial community is a significant issue, while most previous studies only covered a narrow salinity range. Here, variations in seawater prokaryotic communities during the whole salt drying progression (salinity from 3% to 25%) were investigated. According to high‐throughput sequencing results, the diversity, composition, and function of seawater prokaryotic communities varied significantly along the salinity gradient, expressing as decreased diversity, enrichment of some halophilic archaea, and powerful nitrate reduction in samples with high salt concentrations. More importantly, a sudden and dramatic alteration of prokaryotic communities was observed when salinity reached 16%, which was recognized as the change point. Combined with the results of network analysis, we found the increasing of complexity but decreasing of stability in prokaryotic communities when salinity exceeded the change point. Moreover, prokaryotic communities became more deterministic when salinity exceeded the change point due to the niche adaptation of halophilic species. Our study showed that substantial variations in seawater prokaryotic communities along an extremely wide salinity gradient, and also explored the underlying mechanisms regulating these changes. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effects of Bacillus licheniformis and combined herbs extracts on the physiological and immune characteristics, intestinal microbiota, and vibriosis resistance of sea cucumber Apostichopus japonicus. The sea cucumbers were fed with basal diets supplemented with B. licheniformis (B group), combined herbs extracts (C group), or both (BC group). The BC group exhibited the better growth performance and higher digestive and immune enzyme activities, whereas the lowest parameters appeared in the control group. This revealed that dietary B. licheniformis and combined herbs extracts in combination could improve digestion, food intake, phosphatase-responsiveness, and oxidation resistance more efficiently compared with the other groups. The BC group was also more capable of regulating intestinal flora balance of sea cucumbers by increasing the beneficial bacteria related to energy synthesis and metabolic conversion, and inhibiting the potential pathogens associated with organic damage and metabolic disorders. Furthermore, the BC group showed greater ability of improving disease resistance by reducing the cumulative mortality rates and the counts of Vibrio splendidus. These results collectively demonstrated that dietary B. licheniformis and combined herbs extracts could improve the physiological and immune parameters, optimize the microbial community, and enhance the resistance to vibriosis of sea cucumbers, and the health-promoting effects were more obvious by supplying them in combination. [ABSTRACT FROM AUTHOR]

Summary: Nowadays, the true economic and nutritional value of food is underpinned by both origin and quality traits, more often expressed as increased quality benefits derived from the origin source. Gut microbiota contribute to food metabolism and host health, therefore, it may be suitable as a qualifying indicator of origin and quality of economic species. Here, we investigated relationships between the gut microbiota of the sea cucumber (Apostichopus japonicus), a valuable aquaculture species in Asia, with their origins and quality metrics. Based on data from 287 intestinal samples, we generated the first biogeographical patterns for A. japonicus gut microbiota from origins across China. Importantly, A. japonicus origins were predicted using the random forest model that was constructed using 20 key gut bacterial genera, with 97.6% accuracy. Furthermore, quality traits such as saponin, fat and taurine were also successfully predicted by random forest models based on gut microbiota, with approximately 80% consistency between predicted and true values. We showed that substantial variations existed in the gut microbiota and quality variables in A. japonicus across different origins, and we also demonstrated the great potential of gut microbiota to track A. japonicus origins and predict their quality traits. [ABSTRACT FROM AUTHOR]

Apostichopus japonicus is an important invertebrate that is widely used as a tonic food in Asian countries. The purpose of this study is to purify and identify a class of compound, the saponins, from the body wall of A. japonicus, and to establish a new method to determine the quantity of saponins in the sea cucumber. In this study, the saponins of A. japonicus, cladoloside A (CA), were obtained from 80% ethanol extract by column chromatography for the first time and were characterized using the spectral method. The resulting purified saponins were then profiled using 1HNMR, 13CNMR, and ESI-MS, which revealed the CA molecular formula of C53H82O2 and contained a triterpenoid backbone, a methylglucopyranosyl moiety, a quinovopyranosyl, and two xylopyranosyls. A method for the quantitative determination of CA, comprising microwave-assisted extraction, high-performance liquid chromatography, and diode array detector method, was established. Extraction efficiency was optimized by changing microwave power, extraction solvent, volume, time, and temperature. Results showed that under the optimum conditions (extraction time of 10 min, temperature of 45°C, and solvent of 25 mL 70% ethanol under 400 W), the detection limit of CA was 0.0015 mg mL−1, and the recoveries of CA from samples at spiking levels of 10, 20, and 50 µg g−1 ranged from 90.1%–104%. The proposed method was successfully applied to analyze the saponins in different tissues of A. japonicus collected in different seasons. The method developed in this study can provide quantitative technical support for the quality control of A. japonicus. [ABSTRACT FROM AUTHOR]

Effects of dietary Lactobacillus acidophilus and tussah immunoreactive substances (TIS) on disease resistance of sea cucumber (Apostichopus japonicus) against Vibrio splendidus were investigated. Sea cucumbers were fed with a basal diet in the control group (CK group) or were supplemented with L. acidophilus (L group), TIS (T group) or both (LT group). The challenge test with V. splendidus was conducted after the feeding trial. The cumulative mortality rate in the LT group was significantly lower, while the highest mortality occurred in the control group. The LT group showed better digestive and immune parameters compared with the other treatments. Dietary L. acidophilus and TIS in combination could effectively enhance digestive function and food uptake, depress oxidative damage and improve the organismal defence capability. Regarding gut microbiota profiles, the LT group was more capable of inhibiting potentially opportunistic pathogens and regulating intestinal flora balance compared with the other groups. The administration of L. acidophilus and TIS in the diet could effectively improve disease resistance against V. splendidus of sea cucumbers by improving the immune and digestive enzyme activities and modulating intestinal microflora, signalling a potential role in the development and production of aquatic feed. [ABSTRACT FROM AUTHOR]

A new double asymmetric μ1,1-azido bridged binuclear copper(II) complex, [Cu2(μ1,1-N3)2(Him2-py)2(N3)2] (Him2-py = 2-(2'-pyridyl)-4,4,5,5-tetramethylimidazoline-1-hydroxy), has been synthesized and characterized structurally and magnetically. The crystal structure shows this complex is binuclear with copper(II) in a distorted square-pyramidal geometry, bridged by double asymmetric end-on azide ligands. The variable temperature magnetic susceptibility analyses reveal weak antiferromagnetic interaction mediated by the bridge. [ABSTRACT FROM AUTHOR]