Discrimination of dried sea cucumber (Apostichopus japonicus) products from different geographical origins by sequential windowed acquisition of all theoretical fragment ion mass spectra (SWATH-MS)-based proteomic analysis and chemometrics

Differentiation of three commercial tuna species through GC-Q-TOF and UPLC-Q/Orbitrap mass spectrometry-based metabolomics and chemometrics

Food fraud is common in the tuna industry because of the economic benefits involved. Ensuring the authenticity of tuna species is crucial for protecting both consumers and tuna stocks. In this study, GC-Q-TOF and UPLC-Q/Orbitrap mass spectrometry-based metabolomics were used to investigate the metabolite profiles of three commercial tuna species (skipjack tuna, bigeye tuna and yellowfin tuna). A total of 22 and 77 metabolites were identified with high confidence using GC-Q-TOF and UPLC-Q/Orbitrap mass spectrometry, respectively. Further screening via chemometrics revealed that 38 metabolites could potentially serve as potential biomarkers. Hierarchical cluster analysis showed that the screened metabolite biomarkers successfully distinguished the three tested tuna species. Furthermore, a total of 27 metabolic pathways were identified through enrichment analysis based on the Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathways.

Discrimination of three commercial tuna species through species-specific peptides: From high-resolution mass spectrometry discovery to MRM validation

The risk of tuna adulteration is high driven by economic benefits. The authenticity of tuna is required to protect both consumers and tuna stocks. Given this, the study is designed to identify species-specific peptides for distinguishing three commercial tropical tuna species. The peptides derived from trypsin digestion were separated and detected using ultrahigh-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF/MS) in data-dependent acquisition (DDA) mode. Venn analysis showed that there were differences in peptide composition among the three tested tuna species. The biological specificity screening through the National Center for Biotechnology Information's Basic Local Alignment Search Tool (NCBI BLAST) revealed that 93 peptides could serve as potential species-specific peptides. Finally, the detection specificity of species-specific peptides of raw meats and processed products was carried out by multiple reaction monitoring (MRM) mode based on a Q-Trap mass spectrometer. The results showed that three, one and two peptides of Katsuwonus pelamis, Thunnus obesus and Thunnus albacores, respectively could serve as species-specific peptides.

Development of biomarkers to distinguish different origins of red seabreams (Pagrus major) from Korea and Japan by fatty acid, amino acid, and mineral profiling

Red seabream (Pagrus major) has been one of the most popular fish in East Asia since early times. However, the discharge of nuclear wastewater into the sea following the Fukushima nuclear disaster in Japan has led to violations of the country of origin labeling. Therefore, the aim of the present study was to determine the origin of fish based on fatty acid, amino acid, and mineral analyses, and to develop biomarkers that can discriminate between Japanese and Korean red seabream. To identify the differences between the two groups, 29 fatty acid families, 17 amino acids, and 4 minerals were analyzed in 60 fish samples (standard sample collected in autumn), and fatty acid profiles were analyzed using heatmap with hierarchical clustering analysis and orthogonal projections to latent structures discriminant analysis. The top 10 fatty acids that were different between the two groups were selected from all seasonal fish samples by combining variable importance in projection scores and p-values. According to the receiver operating characteristic curve analysis results, we proposed percentage linoleic acid (C18:2n-6, cis) as a candidate biomarker with excellent sensitivity and specificity. This study introduces a strategy to identify the origins of red seabream using linoleic acid obtained from fatty acid analysis.

Investigating the Impact of Disrupting the Glutamine Metabolism Pathway on Ammonia Excretion in Crucian Carp (Carassius auratus) under Carbonate Alkaline Stress Using Metabolomics Techniques

With the gradual decline in freshwater resources, the space available for freshwater aquaculture is diminishing and the need to maximize saline water for aquaculture is increasing. This study aimed to elucidate the impact mechanisms of the disruption of the glutamate pathway on serum metabolism and ammonia excretion in crucian carp (Carassius auratus) under carbonate alkaline stress. A freshwater control group (C group), a 20 mmol/L NaHCO3 stress group (L group), and a 40 mmol/L NaHCO3 stress group (H group) were established. After 30 days of exposure, methionine sulfoximine (MSO) was injected to block the glutamate pathway metabolism, and the groups post-blocking were labeled as MC, ML, and MH. Ultra-high-performance liquid chromatography coupled with the quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) metabolomics technique was employed to detect changes in the composition and content of crucian carp serum metabolites. Significant differential metabolites were identified, and related metabolic pathways were analyzed. The results revealed that, following the glutamate pathway blockade, a total of 228 differential metabolites (DMs) were identified in the three treatment groups. An enrichment analysis indicated significant involvement in glycerophospholipid metabolism, arachidonic acid metabolism, sphingolipid metabolism, purine metabolism, arginine and proline biosynthesis, pantothenate and CoA biosynthesis, glutathione metabolism, and fatty acid degradation, among other metabolic pathways. The results showed that ROS imbalances and L-arginine accumulation in crucian carp after the glutamate pathway blockade led to an increase in oxidative stress and inflammatory responses in vivo, which may cause damage to the structure and function of cell membranes. Crucian carp improves the body's antioxidant capacity and regulates cellular homeostasis by activating glutathione metabolism and increasing the concentration of phosphatidylcholine (PC) analogs. Additionally, challenges such as aggravated ammonia excretion obstruction and disrupted energy metabolism were observed in crucian carp, with the upregulation of purine metabolism alleviating ammonia toxicity and maintaining energy homeostasis through pantothenate and CoA biosynthesis as well as fatty acid degradation. This study elucidated the metabolic changes in crucian carp under carbonate alkaline stress after a glutamate pathway blockade at the cellular metabolism level and screened out the key metabolic pathways, which provide a scientific basis for further in-depth studies on the ammonia excretion of freshwater scleractinian fishes under saline and alkaline habitats at a later stage.

Discovery of candidate biomarkers to discriminate between Korean and Japanese red seabream (Pagrus major) using metabolomics

Red seabream (Pagrus major) is widely consumed in East Asia. As nuclear wastewater is discharged into Japanese waterbodies, the country of origin of marine products must be accurately labeled. Here, we aimed to discover candidate metabolite biomarkers to discriminate between Korean and Japanese red seabream using LC-Orbitrap mass spectrometry. In total, 95 and 138 putative metabolites were detected via chromatographic separation of fish sampled in the warm and cold seasons, respectively. The spectrometric and chromatographic data were analyzed using principal component analysis and orthogonal partial least squares discriminant analysis. We identified 12 and 19 influential metabolites to discriminate between each origin fish in the warm and cold seasons, respectively, using variable importance in projection scores and p values. Anserine was further selected as a candidate biomarker based on receiver operating characteristic curve analysis. This study provides a basis for using anserine to determine the geographic origin of red seabream.

Defence mechanisms of Pinctada fucata martensii to Vibrio parahaemolyticus infection: Insights from proteomics and metabolomics

Survival of pearl oysters is not only challenged by coastal pollution, but also pathogen infection that may eventually incur substantial economic losses in the pearl farming industry. Yet, whether pearl oysters can defend themselves against pathogen infection through molecular mechanisms remains largely unexplored. By using iTRAQ proteomic and metabolomic analyses, we analysed the proteins and metabolites in the serum of pearl oysters (Pinctada fucata martensii) when stimulated by pathogenic bacteria (Vibrio parahaemolyticus). Proteomic results found that a total of 2,242 proteins were identified in the experimental (i.e., Vibrio-stimulated) and control groups, where 166 of them were differentially expressed (120 upregulated and 46 downregulated in the experimental group). Regarding the immune response enrichment results, the pathway of signal transduction was significantly enriched, such as cytoskeleton and calcium signalling pathways. Proteins, including cathepsin L, heat shock protein 20, myosin and astacin-like protein, also contributed to the immune response of oysters. Pathogen stimulation also altered the metabolite profile of oysters, where 49 metabolites associated with metabolism of energy, fatty acids and amino acids were found. Integrated analysis suggests that the oysters could respond to pathogen infection by coordinating multiple cellular processes. Thus, the proteins and metabolites identified herein not only represent valuable genetic resources for developing molecular biomarkers and genetic breeding research, but also open new avenues for studies on the molecular defence mechanisms of pearl oysters to pathogen infection.

UHPLC-MS/MS metabolomics analysis of sea cucumber (Apostichopus japonicus) processed using different methods

The effects of different processing methods on the nutritional components of sea cucumber (Apostichopus japonicus) are of concern to consumers who select sea cucumber products. This study employed liquid chromatography tandem mass spectrometry to examine the metabolites in fresh, unsoaked salted, soaked salted, and instant sea cucumber body wall samples sourced from Dalian, China. Metabolites were evaluated utilizing partial least squares discriminant analysis (PLS-DA) and subsequently subjected to KEGG metabolic pathway analysis for further investigation. PLS-DA effectively discriminated the body wall metabolites of sea cucumbers obtained via various processing techniques. The differential metabolites identified predominantly encompassed amino acids, lipids, and carbohydrates. Subsequent KEGG metabolic pathway analysis demonstrated a significant association between lipid, carbohydrate, and amino acid metabolism and the specific processing methods employed. The assessment of nutritional differences corresponding to the various A. japonicus processing methods was conducted. The findings of this study can assist in the choice of sea cucumber products and the selection of suitable processing methods.

Determination of adulteration, geographical origins, and species of food by mass spectrometry

Food adulteration, mislabeling, and fraud, are rising global issues. Therefore, a number of precise and reliable analytical instruments and approaches have been proposed to ensure the authenticity and accurate labeling of food and food products by confirming that the constituents of foodstuffs are of the kind and quality claimed by the seller and manufacturer. Traditional techniques (e.g., genomics-based methods) are still in use; however, emerging approaches like mass spectrometry (MS)-based technologies are being actively developed to supplement or supersede current methods for authentication of a variety of food commodities and products. This review provides a critical assessment of recent advances in food authentication, including MS-based metabolomics, proteomics and other approaches.

Metabolomics: A suitable foodomics approach to the geographical origin traceability of Ethiopian Arabica specialty coffees

Coffee arabica, originated in Ethiopia, is considered a quality bean for its high sensory qualities, and has a special price in the world coffee market. The country is a pool of genetic diversity for Arabica coffee, and coffee from different regions has a distinct flavor profile. Their exceptional quality is attributed to their genetic diversity, favorable environmental conditions, and agroforestry-based production system. However, the country still needs to benefit from its single-origin product due to a lack of appropriate traceability information to register for its geographical indication. Certification of certain plants or plant-derived products emerged to inform consumers about their exceptional qualities due to their geographical origin and protect the product from fraud. The recently emerging foodomics approaches, namely proteomics, genomics, and metabolomics, are reported as suitable means of regional agri-food product authentication and traceability. Particularly, the metabolomics approach provides truthful information on product traceability. Despite efforts by some researchers to trace the geographical origin of Ethiopian Arabica coffees through stable isotope and phenolic compound profiling and elemental analysis, foodomics approaches are not used to trace the geographical origin of Arabica specialty coffees from various parts of the country. A metabolomics-based traceability system that demonstrates the connection between the exceptional attributes of Ethiopian Arabica specialty coffees and their geographic origin is recommended to maximize the benefit of single-origin coffees.

Analysis of metabolite differences between South Korean and Chinese yellow goosefish (Lophius litulon) using capillary electrophoresis time-of-flight mass spectrometry

The yellow goosefish is a benthic fish that belongs to the family Lophiidae and order Lophiiformes and is distributed in the Yellow and East China Seas. This study aimed to distinguish between yellow goosefish from different geographical origins by analyzing their metabolites. Capillary electrophoresis time-of-flight mass spectrometry was used to analyze metabolite profiles in the muscle tissues of yellow goosefish to distinguish between Korean and Chinese yellow goosefish. In total, 271 putative metabolites were extracted using 50% acetonitrile in water. Principal component analysis and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to distinguish different geographical origins using the metabolite profiles obtained. The R2 and Q2 values of the OPLS-DA model were 0.856 and 0.695, respectively, indicating that the model was well-fitted and had good predictability. The heat map revealed that nucleic acid and amino compounds differed between the Korean and Chinese fish, and the variable importance in the projection scores obtained from OPLS-DA showed that there were geographical differences in the primary metabolites (5'-methylthioadenosine, adenosine, uridine 5-diphosphate, guanosine 5-diphosphate, urea, homocarnosine, O-acetylcarnitine, cycloleucine, cycloleucine S-adenosylmethionine, S-adenosylhomocysteine, ethanolamine, myo-inositol 1-phosphate), which were identified as potential candidate biomarkers.

Hot Air Drying of Sipunculus nudus: Effect of Microwave-Assisted Drying on Quality and Aroma

The present study aimed to investigate the effect of different microwave pre-drying times under hot-air-drying processes on the quality properties and sensory evaluation of Sipunculus nudus (S. nudus). The colour, proximate analysis, amino acid content, fat oxidation, and volatile components of dried S. nudus were determined. Microwave pre-drying could significantly (p < 0.05) increase the drying rate and shorten the drying time. The results of colour, proximate analysis, and amino acid content indicated that microwave pre-drying could improve the quality of the product, resulting in dried S. nudus with less of a loss in nutrients. The samples that underwent microwave pre-drying had a high degree of fatty acid oxidation and low monounsaturated fatty acid content, which facilitated the formation of volatile components. Additionally, the MAD-2 and MAD-3 groups had high relative contents of aldehydes and hydrocarbons, and the FD group had the highest relative content of esters found in the samples. The relative content of ketones and alcohols did not differ significantly between the different drying groups. The finding of this study has important potential for enhancing the quality and aroma of dry S. nudus products with microwave pre-drying during the drying process.

Integrative Application of Transcriptomics and Metabolomics Provides Insights into Unsynchronized Growth in Sea Cucumber (Stichopus monotuberculatus)

Ever-increasing consumer demand for sea cucumbers mainly leads to huge damage to wild sea cucumber resources, including Stichopus monotuberculatus, which in turn exerts negative impacts on marine environments due to the lack of ecological functions performed by sea cucumbers. Aquaculture of sea cucumbers is an effective way to meet consumer demand and restore their resources. Unsynchronous growth is a prominent problem in the aquaculture of sea cucumbers which has concealed unelucidated molecular mechanisms until now. In this study, we carried out an integrative analysis of transcriptomics and metabolomics on fast-growing (SMF) and slow-growing (SMS) groups of S. monotuberculatus cultured in the same environmental conditions. The results revealed that a total of 2054 significantly differentially expressed genes (DEGs) were identified, which are mainly involved in fat digestion and absorption, histidine metabolism, arachidonic acid metabolism, and glutathione metabolism. 368 differential metabolites (DMs) were screened out between the SMF group and the SMS group; these metabolites are mainly involved in glycerophospholipid metabolism, purine metabolism, biosynthesis of unsaturated fatty acids, pyrimidine metabolism, arachidonic acid metabolism, and other metabolic pathways. The integrative analysis of transcriptomics and metabolomics of S. monotuberculatus suggested that the SMF group had a higher capacity for lipid metabolism and protein synthesis, and had a more frequent occurrence of apoptosis events, which are likely to be related to coping with environmental stresses. The results of this study provide potential values for the aquaculture of sea cucumbers which may promote their resource enhancement.

Integrative analyses of widely targeted metabolomic profiling and derivatization-based LC-MS/MS reveals metabolic changes of Zingiberis Rhizoma and its processed products

Zingiberis Rhizoma (ZR) has nutritional value and application potentiality, while Zingiberis Rhizoma Praeparatum (ZRP) and Carbonised Ginger (CG) are two main processed products of ZR based on different methods. Here, we performed a widely targeted metabolomics method with Sequential Windowed Acquisition of all Theoretical fragment ions (SWATH) mode to analyze differential metabolites in ZR, ZRP and CG. Additionally, the chemical derivatization was applied to characterize different submetabolomes and improve the separation effect and MS response of metabolites. In total, 369 metabolites were identified and divided into 14 categories, 104 of which were differential metabolites. Our results suggest that carbohydrates, nucleotides, organic acids, vitamins, lipids, indoles, alkaloids, and terpenes contributed to a downward trend after processing, but the maximum content of flavanones, phenylpropanes and polyphenols appeared in ZRP, and that of alcohols appeared in CG. These findings serve as promising perspectives for developing functional food in ZR, ZRP and CG.

Molecular mechanism of protein dynamic change in Pacific oyster (Crassostrea gigas) during depuration at different salinities uncovered by mass spectrometry-based proteomics combined with bioinformatics

Salinity stress during depuration of Pacific oysters (Crassostrea gigas) leads to degradation in quality; therefore, an understanding of the molecular mechanisms regulating dynamic changes during depuration is needed. Here, C. gigas was depurated for 72 h at salinities ranging from 26 to 38 g/L, a ± 10-20% fluctuation from that in the production area, and the gill proteomes were analyzed by sequential window acquisition of all theoretical fragment ion mass spectra (SWATH-MS). Of the 1218 proteins analyzed, 241 were differentiating proteins (DPs). Salinity stress led to increased levels of DPs associated with glycolysis and the extracellular matrix-receptor interaction pathway, and decreased levels of DPs associated with the citric acid cycle, lipid metabolism, genetic information processing, and cell transformation, especially in oysters exposed to 38 g/L salinity (+20%). Controlling salinity fluctuation within ± 10% of the production area during depuration was conducive to maintaining quality in C. gigas.

Integrated application of multi-omics approach and biochemical assays provides insights into physiological responses to saline-alkaline stress in the gills of crucian carp (Carassius auratus)

Given the decline of freshwater resources in recent years, the accessible space for freshwater aquaculture is rapidly shrinking, and aquaculture in saline-alkaline water has become a critical approach to meet the rising demand. However, the molecular mechanism behind the adverse effects of saline-alkaline water on fish and the regulatory mechanism in fish tolerance remains unclear. Here, adult crucian carp (Carassius auratus) were exposed to 60 mmol/L NaHCO₃ for 30 days. It was observed that long-term carbonate alkalinity (CA) exposure not only caused gill oxidative stress but also changed the levels of several physiological parameters associated with ammonia transport, including blood ammonia, urea nitrogen (BUN), glutamine (Gln), and glutamine synthetase (GS). According to the metabolomics study, differential metabolites (DMs) engaged in various metabolic pathways, such as glycerophospholipid metabolism, sphingolipid metabolism, and arachidonic acid metabolism. In addition, transcriptomics data showed that differentially expressed genes (DEGs) were closely related to ammonia transport, apoptosis, and immunological response. In general, comprehensive multi-omics and biochemical analysis revealed that crucian carp might adopt Rh glycoprotein as a carrier to mediate ammonia transport and increase glutamine and urea synthesis under long-term high saline-alkaline stress to mitigate the adverse effects of blocked ammonia excretion. Simultaneously, saline-alkaline stress caused the destruction of the antioxidant system and the disorder of lipid metabolism in the crucian carp gills, which induced apoptosis and immunological response. To our knowledge, this is the first study to investigate fish's molecular and metabolic mechanisms under saline-alkaline stress using integrated metabolomics, transcriptomics, and biochemical assays. Overall, the results of this study provided new insights into the molecular mechanism behind the adverse effects of saline-alkaline water on fish and the regulatory mechanism in fish tolerance.

Mass spectrometry in food authentication and origin traceability

Food authentication and origin traceability are popular research topics, especially as concerns about food quality continue to increase. Mass spectrometry (MS) plays an indispensable role in food authentication and origin traceability. In this review, the applications of MS in food authentication and origin traceability by analyzing the main components and chemical fingerprints or profiles are summarized. In addition, the characteristic markers for food authentication are also reviewed, and the advantages and disadvantages of MS-based techniques for food authentication, as well as the current trends and challenges, are discussed. The fingerprinting and profiling methods, in combination with multivariate statistical analysis, are more suitable for the authentication of high-value foods, while characteristic marker-based methods are more suitable for adulteration detection. Several new techniques have been introduced to the field, such as proton transfer reaction mass spectrometry, ambient ionization mass spectrometry (AIMS), and ion mobility mass spectrometry, for the determination of food adulteration due to their fast and convenient analysis. As an important trend, the miniaturization of MS offers advantages, such as small and portable instrumentation and fast and nondestructive analysis. Moreover, many applications in food authentication are using AIMS, which can help food authentication in food inspection/field analysis. This review provides a reference and guide for food authentication and traceability based on MS.

Cleavage sites and non-enzymatic self-degradation mechanism of ready-to-eat sea cucumber during storage

The non-enzymatic degradation of ready-to-eat sea cucumber (RSC) was closely related to the quality of sea cucumber products. When stored at 37 °C for 0-30 d, the hardness of RSC decreased by 86.7% and the proportion of free water increased by 12.71%. The content of free hydroxyproline increased from 8.33 μg/g to 24.12 μg/g. Label-free quantitative proteomics analysis showed that protein was prone to break at the sites of G, Q, N, D, and L, and the peptide bonds in QI, DL, NL, RI, EF and SY were much more liable to break. Edman degradation method showed that the breakage sites of RSC were at S, D, H, E, and V. NL, NA and NG calculated by B3LYP/6-31G(d) showed that the relative free energies in the initial cyclization step were 53.20, 143.53 and 78.10 kcal/mol, respectively, which may be the rate-determining step for peptide bond cleavage.

Proteomics for species authentication of cod and corresponding fishery products

Seafood substitutions is a global problem and come under the spotlight in recent years. In Taiwan, Greenland halibut is usually substituted for the cod because of its lower price. Nowadays, DNA technology is widely used for fish species identifications; however, it still has concern about the DNA of processed fishery products might be destroyed. This study was designed to develop a proteomic-based method for fish and fishery product authentication by using ultra performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) with Sequential window acquisition of all theoretical fragment ion spectra (SWATH). The protein biomarkers from the meat of Alaska pollock, Atlantic cod, and Greenland halibut were identified and validated for species authentication of cod and corresponding fishery products, which might prevent consumer substitutions and fish product mislabeling. Besides, the E. coli proteins can be measured from existing SWATH-MS data though retrospective analysis successfully, it might present the quality of fish meat.

Honey proteomic signatures for the identification of honey adulterated with syrup, producing country, and nectar source using SWATH-MS approach

Honey is widely consumed by humans, due to its multiple applications as a food constituent and its therapeutic effects. This study reports on the discrimination of honey products from different geographical and botanical sources, as well as honey products containing distinct forms of syrup used in honey adulteration. Sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS)-based proteomic analysis combined with chemometrics was successfully applied in identifying characteristic proteins that can be used as biomarkers of the original source of honey. Honey samples from different producing regions (Tainan, Changhua, and Taichung), countries (Taiwan and Thailand), and distinct botanical sources (longan and litchi) were clearly distinguished by the developed orthogonal projections to latent structures discriminant analysis (OPLS-DA) model with good fitness and prediction ability. Furthermore, we successfully discriminated the adulteration of honey with syrup in different proportions (even with honey content as low as 20%) with this proteomic SWATH-MS platform.

Discrimination of meat from fur-producing and food-providing animals using mass spectrometry-based proteomics

Non-edible meat from fur-producing animals entering into meat consumption chain could pose a serious threat to public health. For the purpose of risk prevention and control of meat safety, in this study, marker peptides for discriminating non-edible meat of fur-producing animals (including fox, silver fox, blue fox, raccoon dog, ussuri raccoon dog, mink and American mink) from meat of food-providing animals (including pig, cattle, sheep and donkey) were explored by shot-gun proteomics and verified by target approach. Two mass spectrometry platforms combined with bioinformatic and chemometric tools were integratedly emloyed for method development. Meat samples were first subjected to in-solution protein digestion and the subsequently tryptic peptides were profiled and quantitated by ultra-high pressure liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q/TOF MS) with sequential windowed acquisition of all theoretical fragment ion mass spectra (SWATH-MS) mode. Candidate marker peptides screened by chemometric tools were further filtered for their biological specificity and detectability through bioinformatics analysis as well as multiple reaction monitoring (MRM) verification with UHPLC-triple quadrupole mass spectrometry (UHPLC-QQQ MS). As a result, 9 peptides, out of 104 candidates, were selected as markers for discriminating analysis, of which DQTLQEELAR was validated as primary indicator of non-edible meat from the concerned fur-producing animals. An MRM method based on the developed marker peptides for routine use was finally proposed for risk alarming of non-edible meat from fur-producing animals in food safety control.

Uncovering proteome variations of differently heat-treated sea cucumber (Apostichopus japonicus) by label-free mass spectrometry

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.

Effect of geographic variation on the proteome of sea cucumber (Stichopus japonicus)

Sea cucumber is a sensitive organism that is easily challenged by environmental change. The aim of this study was to characterize the proteome of sea cucumbers from 5 main Chinese origins, including Xiamen (XM), Dalian (DL), Weihai (WH), Yantai (YT) and Qingdao (QD). In this work, a tandem mass tag (TMT) labeling proteomic approach was applied to identify and quantify the proteome of sea cucumber. A total of 5051 proteins were identified in the body wall; among those proteins, 1594 proteins (31.6%) were identified as enzyme proteins, and 33 proteins belonged to collagen. In addition, the 10 most highly abundant proteins were further discussed. Among all quantified proteins, 2266 were significantly differentially expressed proteins (SDEPs) across the 5 origins. These SDEPs were related to pigmentation (5 proteins), antioxidant activity (13 proteins), and immune system processes (29 proteins). Based on SDEPs, DL differed the most from QD and XM, as well as WH and YT, as shown in principal component analysis (PCA) and hierarchical clustering. In conclusion, one-fourth of the significantly different proteins found in the sea cucumber body wall among the 5 main Chinese locations indicated the sensitivity of sea cucumber to variations in temperature, environment, and feeding.

Geographical Origin Authentication of Agri-Food Products: Α Review

This study is a systematic literature review of geographical origin authentication by elemental analytical techniques. Authentication and certification of geographic origin of agri-food products is a useful tool toward the protection of the quality for products. The aim of this work was to map the current state of research in the area of agricultural products and food, identifying emerging fields to the geographical origin of products. The article is divided in three parts. The first part of the article deals with the analytical techniques applied in the food authentication. Special mention is made to elemental analysis and multiple isotope ratio. The second section focuses on statistically published data concerning published research for geographical origin authentication for the period 2015-2019. Specific results are presented inter alia: number of articles according to the type of product, articles according to the type of the analytical techniques, and others. The third part contains characteristic results from articles that were published in the period 2015-2019, on certification of geographical origin on specific agricultural products.

Cell metabolomics to study the cytotoxicity of carbon black nanoparticles on A549 cells using UHPLC-Q/TOF-MS and multivariate data analysis

Carbon black nanoparticles (CBNPs) are core component of fine particulate matter (PM2.5) in the atmosphere. It was reported that the particle in the atmosphere with smaller size and the larger the specific surface area are easier to reach the deep respiratory tract or even the alveoli through the respiratory barrier and cause lung injury. Therefore, it has been believed that ultrafine or nanometer particles with more toxic than those with larger particle sizes. Moreover, it was confirmed that CBNPs could induce inflammation, oxidative stress and changes in cell signaling and gene expression in mammalian cells and organs. However, the cytotoxicity mechanism of them has been uncertain so far. The aim of the present study was to explore the underlying mechanism of cytotoxicity induced by CBNPs on A549 cells. In the current research, the viabilities of A549 cells were detected by Cell Counting Kit-8 (CCK-8) assay. The further metabolomics studies were conducted to detect the cytotoxic effect of CBNPs on A549 cells with an IC50 value of 70 μg/mL for 48 h. Potential differential compounds were identified and quantified using a novel on-line acquisition method based on ultra-liquid chromatography quadrupole time-of-flight mass spectrometry(UHPLC-Q-TOF/MS). The cytotoxicity mechanism of CBNPs on A549 cells was evaluated by multivariate data analysis and statistics. As a result, a total of 32 differential compounds were identified between CBNPs exposure and control groups. In addition, pathway analysis showed the metabolic changes were involved in the tricarboxylic acid (TCA) cycle, alanine, aspartate and glutamate metabolism, histidine metabolism and so on. It is also suggested that CBNPs may induce cytotoxicity by affecting the normal process of energy metabolism and disturbing several vital signaling pathways and finally induce cell apoptosis.