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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]

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]

The sea cucumber Apostichopus japonicus is an economically important marine organism, and its aquaculture has rapidly developed in China. The very large market demand puts forward higher requirements for the economically efficient breeding of sea cucumbers. Sex and the associated reproductive processes have been reported to affect the physiological characteristics of sea cucumbers. However, little is known about the metabolism differences that related to sex and the associated reproductive processes and their potential effects on the efficiency of A. japonicus aquaculture. In this study, ultra-performance liquid chromatography was applied to investigate the variations in metabolic profiles in cell-free coelomic fluids (CCFs) of sea cucumbers of different sexes and reproductive states. A total of 4435 metabolites were detected, and the metabolic profiles of A. japonicus were significantly affected by both sexes and reproductive process. The differentially abundant metabolites in CCFs of A. japonicus of different sexes and reproductive states were also screened and analyzed. The findings revealed that unsaturated fatty acid synthesis and phenylalanine metabolism were the most significantly changed pathways. Moreover, the weakest ability to synthesize capsaicin using phenylalanine was found in A. japonicus after spawning. Our study provides new insights into the metabolic response of A. japonicus during the reproductive process, and also provides valuable references for the economically efficient breeding of A. japonicus. [Display omitted] • Metabolomes in sea cucumbers with different sexes and reproductive states were compared. • Both sex and reproductive processes are associated with the metabolic profiles of sea cucumbers. • Female sea cucumbers had higher levels of unsaturated fatty acids than males. • Post-spawning sea cucumbers had the weakest ability to synthesize capsaicin. [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]

Bioassay-guided fractionation of the ethanolic extract of the stem bark of Albizia julibrissin led to the isolation of ten new oleanane-type triterpenoid saponins, julibrosides J 37 –J 46 ( 1 – 10 ), along with six known analogues ( 11 – 16 ). In addition, 11 prosapogenins ( 17 – 27 ) were prepared by mild or strong alkaline hydrolysis of the total saponin. The structures of 1 − 27 were determined by spectroscopic and chemical means, and their cytotoxicities against four human cancer cell lines, BGC-823, A549, HCT-116, and HepG2 were evaluated. Compounds 5 – 16 exhibited significant inhibitory activity with IC 50 values ranging from 2.59 to 9.30 μM, and 8 turned out to be the most active compound with all IC 50 values < 5 μM. A preliminary structure-activity relationship of these saponins clearly indicated that the outer monoterpenoid moiety (MT′) is a crucial substituent for cytotoxicity, and the linkage sites of the MT′ unit greatly influenced the activity. It could also be inferred that the existence of 16-OH of the aglycone almost has no effect on cytotoxicity and the N -acetyl-glucosamine moiety at C-3 seems to enhance activity. [ABSTRACT FROM AUTHOR]

The sea cucumber Apostichopus japonicus is one of the most dominant and economically important aquaculture species in China. Saponin, which possesses notable biological and pharmacological properties, is a key determinant of the nutritional and health value of A. japonicus. In the present study, we amplified the full-length cDNA of a phosphomevalonate kinase (PMK) gene (named AjPMK) using rapid amplification of cDNA ends (RACE). Subsequently, we engineered a recombinant AjPMK (rAjPMK) protein and assessed its enzymatic activity by enzyme-linked immunosorbent assay (ELISA). Proteins that interact with rAjPMK were screened and identified via pull-down assay combined with liquid chromatography with tandem mass spectrometry (LC-MS/MS). We found that the full-length cDNA of AjPMK contained 1354 bp and an open reading frame (ORF) of 612 bp. The AjPMK protein was predicted not to contain a signal peptide but to contain a phosphonolate kinase domain seen in higher eukaryotes and a P-loop with a relatively conserved nucleoside triphosphate hydrolase domain. The molecular weight of the AjPMK protein was estimated to be 23.81 kDa, and its isoelectric point was predicted to be 8.72. Phylogenetic analysis showed that AjPMK had a closer evolutionary relationship with genes from starfish than with those of other selected species. Besides, we found that rAjPMK synthesized mevalonate-5-diphosphate, interacted either directly or indirectly with crucial pattern recognition receptors (PRRs) and was regulated by immune-related processes, including antioxidative reactions, stress resistance responses and enzyme hydrolysis. Moreover, AjPMK also interacted with farnesyl pyrophosphate synthase, an enzyme reported to be involved in saponin biosynthesis. Together, our findings implied that AjPMK may be directly involved in saponin biosynthesis and the regulation of various innate immune processes. • A phosphomevalonate kinase (PMK) gene was identified in sea cucumber Apostichopus japonicus. • AjPMK is involved in sea cucumber saponin biosynthesis. • AjPMK might be regulated by multiple immune processes. [ABSTRACT FROM AUTHOR]

The mariculture environment is a sink of microplastics (MPs) due to its enclosed nature and mass use of plastics. Nanoplastics (NPs) are MPs with a diameter <1 μm that have a more toxic effect on aquatic organisms than other MPs. However, little is known about the underlying mechanisms of NP toxicity on mariculture species. Here, we performed a multi-omics investigation to explore gut microbiota dysbiosis and associated health problems induced by NPs in juvenile sea cucumber Apostichopus japonicus, a commercially and ecologically important marine invertebrate. We observed significant differences in gut microbiota composition after 21 days of NP exposure. Ingestion of NPs significantly increased core gut microbes, especially Rhodobacteraceae and Flavobacteriaceae families. Additionally, gut gene expression profiles were altered by NPs, especially those related to neurological diseases and movement disorders. Correlation and network analyses indicated close relationships between transcriptome changes and gut microbiota variation. Furthermore, NPs induced oxidative stress in sea cucumber intestines, which may be associated with intraspecies variation in Rhodobacteraceae in the gut microbiota. The results suggested that NPs were harmful to the health of sea cucumbers, and they highlighted the importance of the gut microbiota in the responses to NP toxicity in marine invertebrates., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Apostichopus japonicus (sea cucumber) is one of the most valuable aquaculture species in China; however, different diseases can limit its economic development. Recently, a novel disease, body vesicular syndrome (BVS), was observed in A. japonicus aquaculture. Diseased animals displayed no obvious phenotypic characteristics; however, after boiling at the postharvest stage, blisters, lysis, and body ruptures appeared. In this study, a multiomics strategy incorporating analysis of the gut microbiota, the pond microbiome, and A. japonicus genotype was established to investigate BVS. Detailed analyses of differentially expressed proteins (DEPs) and metabolites suggested that changes in cell adhesion structures, caused by disordered fatty acid β-oxidation mediated by vitamin B5 deficiency, could be a putative BVS mechanism. Furthermore, intestinal dysbacteriosis due to microbiome variations in pond water was considered a potential reason for vitamin B5 deficiency. Our BVS index, based on biomarkers identified from the A. japonicus gut microbiota, was a useful tool for BVS diagnosis. Finally, vitamin B5 supplementation was successfully used to treat BVS, suggesting an association with BVS etiology. IMPORTANCE Body vesicular syndrome (BVS) is a novel disease in sea cucumber aquaculture. As no phenotypic features are visible, BVS is difficult to confirm during aquaculture and postharvest activities, until animals are boiled. Therefore, BVS could lead to severe economic losses compared with other diseases in sea cucumber aquaculture. In this study, for the first time, we systematically investigated BVS pathogenesis and proposed an effective treatment for the condition. Moreover, based on the gut microbiota, we established a noninvasive diagnostic method for BVS in sea cucumber.

The core plays a crucial role in achieving high performance of linear hole transport materials (HTMs) toward the perovskite solar cells (PSCs). Most studies focused on the development of fused heterocycles as cores for HTMs. Nevertheless, nonfused heterocycles deserve to be studied since they can be easily synthesized. In this work, we reported a series of low-cost triphenylamine HTMs (M101-M106) with different nonfused cores. Results concluded that the introduced core has a significant influence on conductivity, hole mobility, energy level, and solubility of linear HTMs. M103 and M104 with nonfused oligothiophene cores are superior to other HTMs in terms of conductivity, hole mobility, and surface morphology. PSCs based on M104 exhibited the highest power conversion efficiency of 16.50% under AM 1.5 sun, which is comparable to that of spiro-OMeTAD (16.67%) under the same conditions. Importantly, the employment of M104 is highly economical in terms of the cost of synthesis as compared to that of spiro-OMeTAD. This work demonstrated that nonfused heterocycles, such as oligothiophene, are promising cores for high performance of linear HTMs toward PSCs.