Search

Bivalves, a highly diverse and the most evolutionarily successful class of invertebrates native to aquatic habitats, provide valuable molecular resources for understanding the evolutionary adaptation and aquatic ecology. Here, we reported a high-quality chromosome-level genome assembly of the razor clam Sinonovacula constricta using Pacific Bioscience single-molecule real-time sequencing, Illumina paired-end sequencing, 10X Genomics linked-reads and Hi-C reads. The genome size was 1,220.85 Mb, containing scaffold N50 of 65.93 Mb and contig N50 of 976.94 Kb. A total of 899 complete (91.92%) and seven partial (0.72%) matches of the 978 metazoa Benchmarking Universal Single-Copy Orthologs were determined in this genome assembly. And Hi-C scaffolding of the genome resulted in 19 pseudochromosomes. A total of 28,594 protein-coding genes were predicted in the S. constricta genome, of which 25,413 genes (88.88%) were functionally annotated. In addition, 39.79% of the assembled genome was composed of repetitive sequences, and 4,372 noncoding RNAs were identified. The enrichment analyses of the significantly expanded and contracted genes suggested an evolutionary adaptation of S. constricta to highly stressful living environments. In summary, the genomic resources generated in this work not only provide a valuable reference genome for investigating the molecular mechanisms of S. constricta biological functions and evolutionary adaptation, but also facilitate its genetic improvement and disease treatment. Meanwhile, the obtained genome greatly improves our understanding of the genetics of molluscs and their comparative evolution.

The small athecate dinoflagellate Karlodinium zhouanum is a species recently described in the coastal waters of China. K. zhouanum is morphologically similar to Karlodinium veneficum, a typical ichthyotoxic blooming karlotoxin‐producing species, and it is impossible to distinguish between these two species based on light microscopy. In this study, strains of K. zhouanum isolated from the East China Sea were studied. By analyzing toxins, toxicity, lipid characteristics and typical molecular and physiological traits of this species, K. zhouanum was shown to be nontoxic to brine shrimp and widely spread over the coastal waters of China. No karlotoxin‐like toxin was detected by liquid chromatography‐mass spectrometry (LC–MS). Instead of gymnodinosterol, the critical sterol in toxic K. veneficum, 27(nor)‐24S‐4α‐Methyl‐5α‐ergosta‐8(14)‐en‐3β‐ol (NEE) was dominant in K. zhouanum, while gymnodinosterol was absent. These sterol characteristics may provide not only support for the species separation between toxic and nontoxic species of Karlodinium but also environmental survey tools to differentiate the contribution of nontoxic Karlodinium strains, which has been unclear until now.

The ionic conductivity and small size of the hydrogen ion make it an ideal charge carrier for hydrogen-ion energy storage (HES); however, high-voltage two-electrode configurations are difficult to construct as the result of the lack of efficient cathodic energy storage. Herein, the high potential fast anionic redox at the cathode of reduced graphene oxide (rGO) was applied by introducing redox additive electrolytes. By coupling the storing hydrogen ion in the Ti3 C2 Tx at the anode, a HES with a voltage of 1.8 V and a plateau voltage at 1.2 V was constructed. Compared with 2.2 Wh kg-1 for the low-voltage Ti3 C2 Tx //Ti3 C2 Tx , the specific energy of asymmetric rGO//Ti3 C2 Tx reaches 34.4 Wh kg-1 . Furthermore, it possesses an energy density of 23.7 Wh kg-1 at high power density of 22.5 kW kg-1 . Thus, this study provides a novel guideline for constructing high-voltage fast HES full cells.

Steryl glycosides (SGs) are sterol conjugates found in various plants, especially in those making up human diets. It has been demonstrated that SGs have potential health benefits, and they could be used as food supplements in a variety of food matrixes. Marine microalgae are a potential resource for human food and ingredients. In this study, gas chromatography-triple quadrupole mass spectrometry (GC-QQQ-MS) was used to characterize unknown SGs in eight microalgae belonging to different classes (Isochrysis galbana 3011, Pavlova viridis, Platymonas helgolandica, Conticribra weissflogii, Thalassiosira pseudonana, Nitzschia closterium, Gymnodinium sp., and Karlodinum veneficum).; Results: The SGs were first extracted from lyophilized algae with chloroform-methanol, purified by solid-phase extraction and analyzed as trimethylsilyl derivatives. Nine SGs have been identified. In particular, new SGs like occelasteryl glycoside and stellasteryl glycoside were found in Gymnodinium sp., 24-methylene cholesteryl glycoside was detected in P. helgolandica, and 4,24-dimethylcholestan-3-yl glycoside was identified as the main constituent of microalga K. veneficum. The results also showed that the compositions of SGs in different microalgae varied, with a range of 5.234 to 0.036 g kg-1 , and microalga P. viridis contained the most abundant SGs.; Conclusion: GC-QQQ-MS is a powerful tool to detect SGs with different structures from a variety of microalgae. The compositions of SGs in different microalgae varied greatly. Microalgae are a good source of highly valued SGs. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.

RATIONALE Diacylgycerol-N-trimethylhomoserine (DGTS) and diacylglycerylhydroxymethyl-N,N,N-trimethyl-β-alanine (DGTA) are structural isomers that are the most commonly described betaine lipids in microalgae. The structural differentiation and precise identification of DGTS and DGTA in microalgae need to be established during mass spectrometry analysis. METHODS Total lipid was extracted from Amphora spp. with CHCl3 /CH3 OH (1:1, v/v). The qualitative analysis of DGTS and DGTA in Amphora spp. was carried out using Li+ /H+ dual mode by ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry operating in MSE mode (UPLC/QTOF MSE ). RESULTS Characteristic fragment ions [C10 H22 O5 N]+ at m/z 236.15 and [C7 H14 O2 N]+ at m/z 144.10 from the [M + H]+ precursor ion can be used for the qualitative analysis of both DGTA and DGTS, whereas the loss of m/z 87 and 74 from the [M + Li]+ precursor ion are specific for DGTS, and the loss of m/z 103 from the [M + Li]+ precursor ion is only for DGTA. As a result, 9 DGTSs and 16 DGTAs with different fatty acids were identified simultaneously in Amphora spp. Semi-quantitative analysis of DGTS and DGTA in Amphora spp. showed that the contents of DGTS ranged from 0.003 to 0.438 nmol mg-1 dw, and that of DGTA from 0.004 to 0.414 nmol mg-1 dw. CONCLUSIONS This is the first report to achieve the ambiguous structural identification of DGTS and DGTA by UPLC/QTOF MSE using dual Li+ /H+ adduct ion mode, which has remained a challenge in the past. It could provide new insights into their phylogeny and be helpful to characterize the natural phytoplankton communities as intact polar lipid biomarkers. Copyright © 2017 John Wiley & Sons, Ltd.

SUMMARY This study provides evidence that flg22, the most conserved 22-amino acid peptide in the N-terminal part of bacterial flagellin can trigger the defense responses of Pyropia haitanensis (Bangiales, Rhodophyta). The defense responses are a chain of events including release of H2O2 and free unsaturated fatty acids C20:4, consumption of C18:3, and the chemical or enzymatic oxidation of both C20 and C18 polyunsaturated fatty acids. Oxidized C20 and C18 fatty acids lead to the production of corresponding hydroperoxy and hydroxylated derivatives, such as 9-hydroperoxy octadecadienoic acid, 8-hydroperoxy eicosapentaenoic acid, and 8-hydroxyl eicosapentaenoic acid, which could be further oxidatively metabolized to yield saturated aldehydes and ketone. Changes of three typical hormones jasmonate, methyl jasmonate, and salicylic acid were observed. Contrary to the increase of jasmonate and methyl jasmonate, salicylic acid was decreased. The expression of key enzymes of oxylipin pathway PhLOX and PhLOX2 were upregulated. However, some defense and antioxidant related genes including PhHsp 70, Phsod , and PhRboh were downregulated markedly at the early stage of flg22 challenge. Overall, our results imply that red algae have evolved a similar defense response and may share the conservative-recognizing receptor for flg22 as in higher plants.

A method using high-performance liquid chromatography coupled with tandem mass spectrometry was developed for simultaneous determination of organic acids in microalgae. o-Benzylhydroxylamine was used to derivatize the analytes, and stable isotope-labeled compounds were used as internal standards for precise quantification. The proposed method was evaluated in terms of linearity, recovery, matrix effect, sensitivity, and precision. Linear calibration curves with correlation coefficients of >0.99 were obtained over the concentration range of 0.4–40 ng mL−1 for glycolic acid, 0.1–10 ng mL−1 for malic acid and oxaloacetic acid, 0.02–2 ng mL−1 for succinic acid and glyoxylic acid, 4–400 ng mL−1 for fumaric acid, 20–2000 ng mL−1 for isocitric acid, 2–200 ng mL−1 for citric acid, 100–10000 ng mL−1 for cis-aconitic acid, and 1–100 ng mL−1 for α-ketoglutaric acid. Analyte recoveries were between 80.2 and 115.1% and matrix effect was minimal. Low limits of detection (0.003–1 ng mL−1) and limits of quantification (0.01–5 ng mL−1) were obtained except cis-aconitic acid. Variations in reproducibility for standard solution at three different concentrations levels were < 9%. This is the first report of the simultaneous analysis of ten organic acids in microalgae, which promotes better understanding of their growth state and provides reference value for high yield microalgae culture. This article is protected by copyright. All rights reserved

The diatom Conticribra weissflogii is a microalga with high nutrition value, rich in docosahexaenoic acids (DHA) and eicosapentaenoic acids (EPA). In order to study the effect of culture conditions on the changes of lipid compositions, the intact lipid structural profiles and fatty acids in C. weissflogii were monitored under static and aerated culture conditions. The results showed that, lipids identified in C. weissflogii were neutral lipid triacylglycerols (TAG), betaine lipid diacylglycerylcarboxy‐N‐hydroxymethyl‐choline (DGCC), phosphatidylcholine (PC) and four classes of photosynthetic glycerolipids. The profiles of lipid metabolites of C. weissflogii were different between two culture modes, with the following characteristics under aerated conditions: TAGs increased significantly, whereas the levels of sulfoquinovosyl diacylglycerol (SQDG), monogalactosyldiacylglycerol (MGDG), and DGCC decreased. Furthermore, higher contents of EPA‐rich TAG and EPA/DHA‐rich DGCC were detected at the end of stationary phase, while EPA/DHA‐rich PC, EPA‐rich MGDG and EPA‐rich digalactosyldiacylglycerol (DGDG) were obtained in the exponential phase under static conditions. Meanwhile, the contents of almost all classes of the essential fatty acids (EFAs)‐enriched lipids increased at onset of stationary phase under aerated conditions. Taken together, given that the high levels of EFAs are required for artificial rearing of marine organisms, aeration is critically important for increasing the production rate and the contents of EFA molecules and therefore increasing the nutritional value of the microalgae.

Phytohormones have attracted wide attention due to their important biological functions. However, their detection is still a challenge because of their complex composition, low abundance and diverse sources. In this study, a novel method of high-performance liquid chromatography with electrospray ionization tandem mass spectrometry was developed and validated for the simultaneous determination of ten phytohormones including indole-3-acetic acid, isopentenyladenine, isopentenyl adenosine, trans-zeatin riboside, zeatin, strigolactones, abscisic acid, salicylic acid, gibberellin A3, and jasmonic acid in Sargassum horneri (S. horneri). The phytohormones were extracted from freeze-dried S. horneri with methanol/water/methanoic acid (15:4:1, v/v/v) analyzed on a Hypersil Gold C18 column and detected by electrospray ionization tandem triple quadrupole mass spectrometry in the multiple reaction monitoring mode. The experimental conditions for the extraction and analysis of phytohormones were optimized and validated in terms of reproducibility, linearity, sensitivity, recovery, accuracy, and stability. Distributions of the phytohormones in the stems, blades, and gas bladder of the S. horneri in drift, fixed, and semi-fixed growing states were investigated for the first time. The observed contents of the phytohormones in S. horneri range from not detected to 5066.67 ng/g (fresh weight). Most phytohormones are distributed mainly in the stems of S. horneri in drift and semi-fixed states.

Engineering large and functional tissue constructs with complex structures (e.g., external ear or nose) for reparation and reconstruction of tissue defects remains one of the major challenges in regenerative medicine, which demands abundant cell sources, advanced biofabrication schemes, and satisfactory integration with the host for long-term efficacy post implantation. Here the 'Microtissue Assembly in 3D-Printed-template-Scaffold' (3D-MAPS), as a platform technology to rapidly fabricate centimeter-sized functional tissue constructs with complex structures, is developed. 3D-MAPS facilitates bottom-up assembly of large-scale manufactured microtissues within the 3D-printed hollow polymeric templates with pre-defined architectures. The assembly and fusion of 2×106 mesenchymal stem cell-based microtissues within the defined 3D-printed template is further enhanced by addition of a natural protein crosslinker (i.e., transglutaminase (TGase)), and thereby achieves construction of centimeter-sized tissue with high cell viability and mechanical stability in vitro within 30 min. Further in vivo implantation of the 3D-MAPS-fabricated ear-like tissue construct in rabbit models assisted by flap prefabrication technique results in increased structural vascular support and strengthened functional survival. Thus, the TGase-enhanced 3D-MAPS demonstrates its potential and feasibility as a powerful biofabrication platform for tissue engineering application.

The shrimp Rimicaris exoculata is the most abundant species in hydrothermal vents. Lipids, the component of membranes, play an important role in maintaining their function normally in such extreme environments. In order to understand the lipid adaptation of R. exoculata (HV shrimp) to hydrothermal vents, we compared its lipid profile with the coastal shrimp Litopenaeus vannamei (EZ shrimp) which lives in the euphotic zone, using ultra performance liquid chromatography electrospray ionization-quadrupole time-of-flight mass spectrometry. As a result, the following lipid adaptation can be observed. (1) The proportion of 16:1 and 18:1, and non-methylene interrupted fatty acid (48.9 and 6.2 %) in HV shrimp was higher than that in EZ shrimp (12.7 and 0 %). While highly-unsaturated fatty acids were only present in the EZ shrimp. (2) Ceramide and sphingomyelin in the HV shrimp were enriched in d14:1 long chain base (96.5 and 100 %) and unsaturated fatty acids (67.1 and 57.7 %). While in the EZ shrimp, ceramide and sphingomyelin had the tendency to contain d16:1 long chain base (68.7 and 75 %) and saturated fatty acids (100 and 100 %). (3) Triacylglycerol content (1.998 ± 0.005 nmol/mg) in the HV shrimp was higher than that in the EZ shrimp (0.092 ± 0.005 nmol/mg). (4) Phosphatidylinositol and diacylglycerol containing highly-unsaturated fatty acids were absent from the HV shrimp. (5) Lysophosphatidylcholine and lysophosphatidylethanolamine were rarely detected in the HV shrimp. A possible reason for such differences was the result of food resources and inhabiting environments. Therefore, these lipid classes mentioned above may be the biomarkers to compare the organisms from different environments, which will be benefit for the further exploitation of the hydrothermal environment.

The two morphologically similar microalgae NMBluh014 and NMBluh-X belong to two different strains of Nannochloropsis oceanica. They possess obviously different feeding effects on bivalves, but are indistinguishable by 18S rRNA and morphological features. In this work, lipidomic analysis followed by principal component analysis and orthogonal projections to latent structures discriminant analysis provided a clear distinction between these strains. Metabolites that definitively contribute to the classification were selected as potential biomarkers. The most important difference in polar lipids were sulfoquinovosyldiacylglycerol (containing 18:1/16:0 and 18:3/16:0) and monogalactosyldiacylglycerol (containing 18:3/16:3 and 20:5/14:0), which were detected only in NMBluh-X. Additionally, an exhaustive qualitative and quantitative profiling of the neutral lipid triacylglycerol (TAG) in the two strains was carried out. The predominant species of TAG containing 16:1/16:1/16:1 acyl groups was detected only in NMBluh-X with a content of ~93.67 ± 11.85 nmol · mg(-1) dry algae at the onset of stationary phase. Meanwhile, TAG containing 16:0/16:0/16:0 was the main TAG in NMBluh014 with a content of 40.25 ± 3.92 nmol · mg(-1) . These results provided the most straightforward evidence for differentiating the two species. The metabolomic profiling indicated that NMBluh-X underwent significant chemical and physiological changes during the growth process, whereas NMBluh014 did not show such noticeable time-dependent metabolite change. This study is the first using Ultra Performance Liquid Chromatography coupled with Electrospray ionization-Quadrupole-Time of Flight Mass Spectrometry (UPLC-Q-TOF-MS) for lipidomic profiling with multivariate statistical analysis to explore lipidomic differences of plesiomorphous microalgae. Our results demonstrate that lipidomic profiling is a valid chemotaxonomic tool in the study of microalgal systematics.

Injectable hydrogels with pH and glucose triggered drug release capability were synthesized based on biocompatible phenylboronic modified chitosan and oxidized dextran through the formation of covalent imine bond and phenylboronate ester. Rheological characterization demonstrated that the gelation rate was rapid, and the moduli of the hydrogels were able to be tuned with chemical composition as well as pH and glucose concentration of the polymer solution. Anticancer drugs could be incorporated inside the hydrogel through the in situ gel forming process and undergo a controlled release by altering pH or glucose concentration. The hydrogels had good biocompatibility with viable and proliferated cells cultured in the three dimensional matrix, and the cell proliferation was suppressed when a small amount of DOX was added, which is benefit for the application of the hydrogels as smart anticancer drug delivery system. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1235–1244

RATIONALE: The precise identification of fatty acids at the sn-2 position of triacylglycerols (TAGs), especially for positional regioisomers (AAB/ABA), needs to be established during mass spectrometry analysis. The detailed structural information about TAGs is significant not only for the assessment of biofuel quality, but also for the tracing of biosynthetic precursors. METHODS: Total lipid was extracted from T. pseudonana by a modified Bligh and Dyer method. The qualitative analysis of TAGs in T. pseudonana was carried out using ultra-performance liquid chromatography/electrospray ionizationquadrupole time-of-flight mass spectrometry (UPLC/ESI-Q-TOF-MS). The raw LC/MS data were analyzed using MassLynx software (version 4.1, Waters). RESULTS: The acyl group at the sn-2 position of the TAGs has been identified unequivocally by [M+Li-R1/3COOHR2CH=CHCOOH] + and the abundance of [M+Li-R1/3COOH-R2CH=CHCOOH] + can be used to confirm whether the TAG isomers are co-eluted. In total, twelve TAGs were identified in T. pseudonana based on the fragmentation patterns discussed above. The data indicated that only C16 fatty acids were located at the sn-2 position, which was important to trace the biosynthetic precursors of TAGs. CONCLUSIONS: We put forward a hypothesis that TAGs in T. pseudonana are only derived from lipids in chloroplasts through prokaryotic biosynthesis pathway based on the precise information of sn-2 fatty acids, which is significant not only for the assessment of biofuel quality, but also for the tracing of biosynthetic precursors. Copyright © 2013 John Wiley & Sons, Ltd.

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantitative determination of phytohormones and betaines in algae. The results showed that phytohormones and betaines were separated with high efficiency on Hypersil Gold C18 and Cnwsil SCX columns. Mass spectrometric detection was performed using positive or negative electrospray ionization in selective reaction monitoring mode (SRM). Linearity of the method was good with correlation coefficients (r 2 )>0.9951 in the range of 0.005-5mg/L. The limits of detection were from 0.004 to 0.86 μg/L and the limits of quantification were in the range from 0.01 to 2.8 μg/L for the investigated phytohormones and betaines. The obtained recoveries varied between 61.33 and 90.39%, and the relative standard deviations were

In this study, the influence of kinematically constrained thermal cycling (heating, isothermal holding and cooling) on the recovery stress in annealed nickel titanium wire was investigated. A 4% pre-strained nickel titanium wire was heated to temperatures (150, 200, 250 and 300 °C) much higher than the austenite finish temperature. It was observed that the maximum recovery stress obtained at different conditions decreases significantly after the first thermal cycle and reduces gradually with further increasing the number of thermal cycles. It was also seen that the recovery stress increases with time during isothermal holding at 150 °C. During isothermal holding at other temperatures, the recovery stress shows an exponential decrease, and the decrease rate of the recovery stress depends on the isothermal holding temperature. The higher isothermal holding temperature is the more the recovery stress decreases. The decrease rate reduces with increasing the number of thermal cycles.

RATIONALE Glycosphingolipids (GSLs) are important components of the cell membrane; however, little is known about GSLs in microalgae. We analyzed GSLs in three strains of Skeletonema microalgae by liquid chromatography coupled with mass spectrometry. METHODS Total lipid was extracted from Skeletonema microalgae. Separation of lipids was achieved via reversed-phase liquid chromatography, and mass spectrometric analysis of the lithium adduct of GSLs was conducted to determine their structures. RESULTS Two types of novel glycosphingolipids were identified from three strains of Skeletonema microalgae. The N-acyl groups were primarily long-chain saturated or monoenoic fatty acids (monounsaturated fatty acids) with 16C and 20 to 24C. The sphingoid long-chain bases (LCB) were sphingosine, sphingadienine and sphingatrienine. The saccharide polar head groups of glycosphingolipids were disaccharide (heptose-hexose) or trisaccharide (heptose-hexose-hexose). Semi-quantitative analysis of GLSs in the three strains of microalgae showed that GSL contents ranged from 0.09 to 8.79 nmol/mg dry microalgae powder. CONCLUSIONS A qualitative method was developed for the identification of GSLs in microalgae. Two types of novel GSLs were identified from three strains of Skeletonema, which might have important biological functions. It could also provide a reliable tool for chemotaxonomy of microalgae. Copyright © 2013 John Wiley & Sons, Ltd.

A facile method based on liquid chromatography coupled with electrospray ionization tandem triple quadrupole mass spectrometry working in selected reaction monitoring mode has been established to analyze toxins in the algae and water samples. Twelve types of toxins (anatoxin, cylindrospermopsin, dinophysistoxin-1, nodularin, okadaic acid, microcystins) were efficiently separated under optimized liquid chromatography coupled with mass spectrometry conditions in the selected reaction monitoring mode. Correlation coefficients of the calibration curves, all felt in the range of 0.9958-0.9998, indicated good linearity. The detection limits of toxins in this method were all lower than 0.20 ng/mL and the quantification limits were in the range from 0.04 to 0.60 ng/mL. Except for anatoxin, cylindrospermopsin, and nodularin, the other toxins' recoveries varied from 55.45 to 140.85%. And the relative standard deviations of interday and intraday precision were at 8.61% (n = 5). The high-performance liquid chromatography (HPLC)/electrospray ionization (ESI)-mass spectrometery (MS) method was also successfully applied to analyze the algae and water samples. Owing to its exclusive selectivity and excellent sensitivity, the developed method is a tool for comprehensive analyses of the 12 types of toxins at nanogram levels.

With the rapid development of mobile electronics and electric vehicles, future electrochemical capacitors (ECs) need to store as much energy as possible in a rather limited space. As the core component of ECs, dense electrodes that have a high volumetric energy density and superior rate capability are the key to achieving improved energy storage. Here, the significance of and recent progress in the high volumetric performance of dense electrodes are presented. Furthermore, dense yet porous electrodes, as the critical precondition for realizing superior electrochemical capacitive energy, have become a scientific challenge and an attractive research focus. From a pore-engineering perspective, insight into the guidelines of engineering the pore size, connectivity, and wettability is provided to design dense electrodes with different porous architectures toward high-performance capacitive energy storage. The current challenges and future opportunities toward dense electrodes are discussed and include the construction of an orderly porous structure with an appropriate gradient, the coupling of pore sizes with the solvated cations and anions, and the design of coupled pores with diverse electrolyte ions.

A method has been established by which to determine aldoses and ketoses in plant material simultaneously. Monosaccharides were extracted by sonication with 80% ethanol and sugar oximes formed by treatment of the resultant extract with hydroxylamine and pyridine at 90C. After reaction, one aliquot of the product was derivatised with acetic anhydride at 90C, whilst a second aliquot was silylated with HMDS and TMCS at 80C. Both reaction mixtures were analysed by GC-MS in the SIM mode. Quantivation was linear within the range 1–4 mg/mL and the detection limit for monosaccharides was 5–25 ng/mL. The absolute recoveries were between 73.0 and 90.2% and the RSDs were 3.1–10.0%. This method was applied to analyse the free monosaccharides in Lyceum barbarum L.; eight monosaccharides were present in amounts between 0.26 and 368.65 mg/mg. Copyright © 2006 John Wiley & Sons, Ltd.

To assess the contribution of NaCl to seafood tastiness, 23Na and 35Cl nuclear magnetic resonance (NMR) spectroscopy was used to determine the mobility of sodium and chloride ions in intact snow crab (Chionoecetes japonicus) leg meat. The T1 (longitudinal relaxation time) values of both 23Na and 35Cl, obtained from inverse recovery experiments, show an evident variance with different heat-processing methods. Heating tends to inhibit both sodium and chloride ion mobility. 35Cl NMR spectra indicate that chloride exists in two different chemical states, one derived from free ions and the other from organic base complexes. © 2000 Society of Chemical Industry