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The elucidation of precise structure of fucoidan is essential for understanding their structure-function relationship and promoting the development of marine drugs. In this work, we firstly reported the oligosaccharide mapping of fucoidan from Holothuria floridana using a combination of hydrothermal depolymerization, hydrophilic interaction liquid chromatography (HILIC) coupled with electrospray mass spectrometry (ESI-FTMS) and high energy collision-induced dissociation (HCD-MS/MS) and 2D NMR analysis. With careful selection of fully deprotonated molecular ions of fucoidan oligosaccharides and their NaBD 4 reduced alditols, HILIC-ESI-HCD-MS/MS provided structurally relevant glycosidic product ions with no sulfate loss for definitive assignment of sequence and sulfation pattern of all the oligosaccharides and their isomers from dp2 to dp7 from hydrothermal depolymerization. The oligosaccharide mapping clarified the structure of fucoidan with various oligosaccharide domains with 2,4-di-O-sulfated and 2-O sulfated fucose residues., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

An HILIC-ESI-MS/MS method was established to analyze ganglioside (GLS) in sea cucumbers. In total, 17 GLS subclasses were detected in six sea cucumber species. The basic sea cucumber GLSs (SC-GLSs) were elucidated as NeuGc2-6Glc1-1Cer (SC-GM 4 ). The polymerization degree of the sialic acid (Sia) of SC-GLSs can be up to 4, and the linkage among Sias was mostly determined to be 2-8 or 2-11. Neu5Gc, sulfated and fucosylated NeuGc prevalently existed in SC-GLSs. Moreover, a new SC-GLSs structure with phosphoinositidyled Sia was first observed in Bohadschia marmorata. For the first time, we demonstrated that the content of SC-GD 4 , which is the dominant GLS in sea cucumbers, was 27-67%. Minor GLSs characterized as SC-GT 2 (Neu5GcMe) and SC-GQ 2 (Neu5GcMe) were also discovered. Additionally, SC-GD 4 and SC-GD 4 (1S) could significantly promote the differentiation of PC12 cells with structure-selectivity (p < 0.05). Our results provide insights into SC-GLSs to elucidate their Sia substituent and core saccharide chain linkage., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The focus of this paper was to investigate the potential of distinguishing sea cucumbers from different production methods (farmed vs wild-caught) and different seasons (autumn vs summer) at the proteomic level. Based on biological mass spectrometry with sequential window acquisition of all the theoretical fragment ion mass spectra (SWATH) acquisition mode, the proteomes of Apostichopus japonicus under farmed and wild production methods were profiled and relatively quantified. The SWATH data were mined by chemometric tools aiming to screen protein biomarkers for the traceability of sea cucumbers in terms of production methods as well as harvesting seasons, respectively. In the end, 4 production-method-sensitive proteins regardless of harvesting seasons and 12 season-sensitive proteins regardless of production methods were unveiled. The protein biomarkers were visually validated by hierarchical clustering heatmap analysis, and gene ontology annotation of biomarkers provided more insight for understanding the intrinsic linkage between the traceability and function of Apostichopus japonicus. [Display omitted] • The proteome of A. japonicus from different methods and seasons were investigated. • Four production-sensitive and 12 season-sensitive protein biomarkers were obtained. • The sensitive protein biomarkers were functionally annotated by GO analysis. • The intrinsic linkage between the protein and production origins was revealed. [ABSTRACT FROM AUTHOR]

• Proteome changes of A. japonicus after heat treatments were measured by SWATH-MS. • 24 and 13 proteins were indicators for heat treatment and three heat procedures. • Majority of the differentiating proteins were function relevant by GO annotation. The effects of heat treatment on the proteome of Apostichopus japonicus have been evaluated using label-free quantitative proteomics by ultrahigh performance liquid chromatography-quadrupole/time of flight (UHPLC-Q/TOF) mass spectrometry with sequential window acquisition of all the theoretical fragment ion (SWATH) acquisition mode. Chemometric tools are integrated to reveal proteomic changes by mining the protein quantitation data from fresh and differently heat-treated samples. SWATH allows the quantitation of 548 proteins, of which 24 proteins are significantly sensitive to heat treatment and 13 proteins vary significantly responding to different heat procedures (boiling, steaming, and microwave heating), and 5 of them are sharing proteins. Gene ontology (GO) annotation of the differentiating proteins highlights most of them are relevant to molecular functions. The results can be favorable to evaluate the effects of heat treatment on the nutrition and function of processed sea cucumbers and facilitate the selection of an optimal thermal treatment. [ABSTRACT FROM AUTHOR]