Protein biomarkers associated with frozen Japanese puffer fish (Takifugu rubripes) quality traits

Rapid and slow thawing of Takifugu rubripes fillets: TMT-labeled proteomics analysis, biochemical and morphological comparison

This study aimed to investigate how running water (rapid, R) and ice-water (slow, I) thawing methods affect the quality of Takifugu rubripes fillets. Thawing shrinkage and changes in extractable proteins quantified by tandem mass tag (TMT)-labeled quantitative proteomics were compared. The results showed that the rapidly thawed fillets were quickly underwent greater shrinkage, and the smaller gap areas were reduced by 7.5 % compared to slow thawing. Compared with fresh fish fillets, the outflow of proteins such as ATP synthase, NADH dehydrogenase, and aconitase within mitochondria increased in both thawing methods that presents cell membrane damage and significant disruptions in mitochondrial structure. The pyruvate dehydrogenase and cytochrome c were significantly upregulated in slow-thawing group. Whereas myosin and structural proteins including the Z-line related were significantly upregulated in the rapid-thawing group. These differential proteins serve as crucial markers for elucidating mechanism involved in muscle quality deterioration under different thawing conditions.

The silent threat: Nanopolystyrene and chrysene pollutants disrupt the intestinal mucosal barrier, new insights from juvenile Siniperca chuatsi

The intestinal mucosal barrier-comprising microbial, mechanical, chemical, and immunological barriers-is critical to protection against pathogens and maintenance of host health; however, it remains unclear whether it is affected by environmental contaminants. Therefore, the present study assessed whether exposure to ambient concentrations of nanopolystyrene (NP) and chrysene (CHR)-two ubiquitous environmental pollutants in the aquatic environment-affect the intestinal mucosal barrier in juvenile Siniperca chuatsi. After exposure for 21 days, S. chuatsi exhibited intestinal oxidative stress and imbalance of intestinal microbial homeostasis. NP and/or CHR exposure also disrupted the intestinal mechanical barrier, as evidenced by the altered intestinal epithelial cell morphology, disrupted structure of intercellular tight junctions, and decreased expression of tight junction proteins. Damage to the intestinal chemical barrier manifested as thinning of the mucus layer owing to the loss and damage of goblet cells. Furthermore, the intestinal immunological barrier was impaired as indicated by the loss of intestinal intraepithelial lymphocytes and increase in pro-inflammatory cytokines, chemokines, and immunoglobulins. These findings collectively suggest that the intestinal mucosal barrier was damaged. This study is, to the best of our knowledge, the first to report that exposure to NP and/or CHR at environmentally relevant concentrations disrupts the intestinal mucosal barrier in organisms and highlight the significance of nanoplastic/CHR pollution for intestinal health.

Nanoplastics and chrysene pollution: Potential new triggers for nonalcoholic fatty liver disease and hepatitis, insights from juvenile Siniperca chuatsi

Nanopolystyrene (NP) and chrysene (CHR) are ubiquitous contaminants in the natural environment; however, research on their hepatotoxicity and associated adverse effects remains relatively inadequate. The present study aimed to investigate the hepatotoxic effects of NP and/or CHR at environmentally relevant concentrations, as well as the underlying molecular mechanisms, in juvenile Siniperca chuatsi (mandarin fish). After a 21-day exposure period, the livers of exposed S. chuatsi exhibited macrostructural and microstructural damage accompanied by oxidative stress. Importantly, our study provides the first evidence that NP exposure leads to the development of nonalcoholic fatty liver disease (NAFLD) and hepatitis in S. chuatsi. Similarly, CHR exposure has also been found, for the first time, to cause hepatic sinusoidal dilatation (HSD) and hepatitis. Exposure to the combination of NP and CHR alleviated the symptoms of NAFLD, HSD, and hepatitis. Furthermore, our comprehensive multi-omic analysis revealed that the pathogenesis of NP-induced NAFLD was mainly due to induction of the triglyceride synthesis pathway and inhibition of the very-low-density lipoprotein secretion process. CHR induced HSD primarily through a reduction in vasoprotective ability and smooth muscle contractility. Hepatitis was induced by activation of the JAK-STAT/NF-kappa B signaling pathways, which upregulated the expression of inflammation-specific genes. Collectively, results of this study offer novel insight into the multiple hepatotoxicity endpoints of NP and/or CHR exposure at environmentally relevant concentrations in organisms, and highlight the importance of nanoplastic/CHR pollution for liver health.

Molecular Mechanisms of Iron Transport and Homeostasis Regulated by Antarctic Krill-Derived Heptapeptide-Iron Complex

In this study, the molecular mechanisms of iron transport and homeostasis regulated by the Antarctic krill-derived heptapeptide-iron (LVDDHFL-iron) complex were explored. LVDDHFL-iron significantly increased the hemoglobin, serum iron, total iron binding capacity levels, and iron contents in the liver and spleen to normal levels, regulated the gene expressions of iron homeostasis, and enhanced in vivo antioxidant capacity in iron-deficiency anemia mice (P < 0.05). The results revealed that iron ions within LVDDHFL-iron can be transported via the heme transporter and divalent metal transporter-1, and the absorption of LVDDHFL-iron involved receptor-mediated endocytosis. We also found that the transport of LVDDHFL-iron across cells via phagocytosis was facilitated by the up-regulation of the high mobility group protein, heat shock protein β, and V-type proton ATPase subunit, accompanied by the regulatory mechanism of autophagy. These findings provided deeper understandings of the mechanism of LVDDHFL-iron facilitating iron absorption.

A strategy to link the changes in the quality traits of Japanese sea bass (Lateolabrax japonicus) muscle and proteins in its exudate during cold storage using mass spectrometry

In this study, Japanese sea bass (Lateolabrax japonicus) was used as a model to link the changes in the quality traits of fish muscle during storage to the change of protein in muscle exudate. Matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS) combined with variables importance in projection (VIP) analysis, and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), were applied to identify the proteins by analyzing the enzymatic hydrolysates of exudates of fish muscle. The link in the identified proteins to the change in the quality traits of fish muscle during storage was explored using pyramid diagrams. Nine proteins were identified from the exudate of Japanese sea bass muscle during 12 days of storage at 4 °C. Of these, four proteins, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), heat shock protein 90 (HSP90), and peroxiredoxin 1 (PRX1), and beta-actin were found to be responsible for the changes in the quality traits of fish muscle. It is promising to correlate the changes in the quality traits of fish muscle and proteins in muscle exudate via MS-based protein identification and the construction of a relationship diagram to understand the mechanism of muscle change at the molecular level.

A TMT-based proteomic approach for investigating the effect of electron beam irradiation on the textural profiles of Litopenaeus vannamei during chilled storage

To elucidate the effect of electron beam irradiation (EBI) on the textural quality of Litopenaeus vannamei, the tandem-mass-tag labeled proteomic method was conducted to illustrate the protein changes in shrimp muscle. The results suggested that shrimp irradiated with 5 kGy exhibited optimum textural traits of hardness, springiness, and chewiness. In total, 486 proteins were identified as differentially abundance proteins (DAPs) in multiple comparison groups. Bioinformatics analysis revealed that most of DAPs participated in cellular process, binding, and catalytic. etc. Various signaling pathways, such as RNA transport and oxidative phosphorylation, were notably enriched by DAPs. The correlation analysis indicated that some DAPs such as Myosin-XVIIIa, projectin, and beta-thymosin 3 were remarkably correlated with the textural properties, which could be proposed as potential biomarkers to assess the irradiation-induced textural variation in shrimp. This study provided an insightful understanding at the protein level to improve the application of EBI to shrimp preservation.

Proteomic changes involved in water holding capacity of frozen bovine longissimus dorsi muscles based on DIA strategy

As freeze/thaw procedure leads to inevitable drip loss, elucidation of mechanism on dynamic changes in water holding capacity (WHC) of muscle is urgently needed. In this study, the proteomic profile by DIA-based strategy, muscle microstructure, water mobility, and WHC indices of bovine longissimus dorsi muscles were investigated under different freezing conditions as well as the correlations among them. Results indicated that slow freezing (SF) sample exhibited significantly higher water mobility, thaw loss, total loss, and shear force value than the samples subjected to fast freezing (FF) and non-frozen control (CON). According to the protein profile, we have identified 272 differential abundance proteins (DAPs), in which more significant proteome changes were found in SF/CON samples as compared with FF/CON. Among the 132 DAPs in FF/SF comparison, correlation analysis revealed that MYL3, DES, SYNE2, EXR, RPL35A, RPS6, and Hsp40 were closely correlated with T₂₃ , thaw loss, and total loss. Accordingly, we considered those seven proteins as potential biomarkers related to WHC of frozen muscle. Our study should give a further understanding on mechanisms behind the various WHC of muscle when subjected to different freezing conditions. PRACTICAL APPLICATIONS: Freezing plays a key role in the preservation method for meat and meat products. However, the drip loss during freezing and subsequent thawing procedure causes considerable economic and nutritional losses. To minimize the losses, elucidation of mechanism on the mechanism of thaw loss formation is urgently needed. DIA-based proteomics is a novel, robust method that provides further understanding on the mechanisms behind the dynamic changes in water holding capacity of muscle. The screened protein biomarkers in frozen muscle would play key roles in the development of WHC, especially for the thaw loss formation. Through this perspective, we can explain the origin of thaw loss and the variation under different freezing conditions, which should provide the meat industries with theoretical basis for reducing losses.

The Investigation of Protein Profile and Meat Quality in Bovine Longissimus thoracic Frozen under Different Temperatures by Data-Independent Acquisition (DIA) Strategy

The influence of freezing on the protein profile and quality traits in bovine Longissimus thoracic (LT) muscle was investigated by the data-independent acquisition (DIA) technique. Compared to fresh meat, a total of 262 proteins were identified as differential abundance proteins (DAPs) in four frozen groups (−12 °C, −18 °C, −38 °C, and −80 °C). According to the bioinformatics analysis, most of the DAPs in the significant Go terms and the KEGG pathway were structure proteins and enzymes. Proteome changes in the frozen bovine muscle at −12 °C and −18 °C were more significant than those at −38 °C and −80 °C. The result was consistent with the deterioration trend of the meat quality. The correlation analysis revealed that 17 proteins were correlated closely with the color, shear force, thawing loss, and cooking loss of the frozen meat, which could be used as putative biomarkers for frozen meat quality. MYO18A and ME3 are newly discovered proteins that are associated with frozen beef quality. In addition, CTTN and SERPINB6 were identified in frozen groups, which exhibited a significant inverse correlation with thawing loss (p < 0.01). These findings reveal the quality changes induced by freezing at the protein molecular level and provide new insights into the control of quality deterioration.

TMT-based quantitative proteomics reveals protein biomarkers from cultured Pacific abalone (Haliotis discus hannai) in different regions

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TMT-based proteomics was used to study and compare the muscle protein profiles of Pacific abalones between northern and southern China.

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729 differential abundance proteins were identified in different regions.

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Fatty acid synthase and other 3 proteins were identified as candidate biomarkers for identification of northern and southern abalone.

Due to latitude, the growth cycle of abalone in southern China is significantly lower than that in the northern regions. Therefore, it often occurs merchants use southern abalone to disguise as northern abalone. This study aims to explore the differences in the muscle proteome of Pacific abalone (Haliotis discus hannai) in different regions. A total of 1,569 proteins were detected and 729 proteins were identified as differential abundance proteins (DAPs) in Haliotis discus hannai cultured in Northern (Liaoning Province) and Southern (Fujian Province) China. Bioinformatics analysis revealed and Western blot verified that fatty acid synthase, troponin I, calpain small subunit 1, and myosin light chain 6 are candidate biomarkers for abalone cultured in different regions. This study provides a deeper understanding of how to distinguish which region abalone is harvested from to improve abalone quality controls, and prevent food fraud.

Life cycle assessment of tiger puffer (Takifugu rubripes) farming: A case study in Dalian, China

In China, energy consumption and carbon emission by the aquaculture industry have become major problems. The tiger puffer (Takifugu rubripes) is an emerging aquaculture species in China, but its environmental impact during the farming process has not yet been evaluated systematically. To the best of our knowledge, this is the first life cycle assessment (LCA) of tiger puffer land-sea relay strategy in Dalian, China. To analyze the environmental impact of the tiger puffer farming process, the following four stages were considered: seed rearing, deep-sea cage farming-1, industrial recirculating aquaculture, and deep-sea cage farming-2. The LCA software GaBi 10.5 academy version and CML-IA-Jan. 2016-world method were used to calculate the environmental impacts. According to the LCA results, marine aquatic ecotoxicity potential was the largest contributor to the environmental impact, and industrial recirculating aquaculture was the largest farming stage in the whole tiger puffer farming process. Energy in the form of electricity, coal, and gasoline was consumed to maintain the power supply in the tiger puffer farming process, and it was a key factor that influenced the environmental performance. Based on the sensitivity and energy analyses, energy consumption for equipment operation at the industrial recirculating aquaculture stage, feed consumption, and gasoline consumption for transportation at the deep-sea cage farming-2 stage need to be carefully considered. The following improvement measures were suggested to improve the environmental performance of tiger puffer farming and the aquaculture industry: establish electricity, wind power, and solar energy integrated management systems; ex-ante LCA for parameter optimization in future technology research and development; and new production strategies such as aquaponics and integrated multi-trophic aquaculture. Moreover, life cycle inventory (LCI) of tiger puffer land-sea relay farming was established to obtain essential information, enrich aquaculture LCI databases, and support aquaculture LCA research.

DIA-based quantitative proteomic analysis on the meat quality of porcine Longissimus thoracis et lumborum cooked by different procedures

A DIA-based quantitative proteomic strategy was used to investigate the effects of different cooking procedures (steaming and boiling) on pork meat quality. Results showed that steamed meats had higher redness, cohesion, springiness, but lower lightness, yellowness, shear force, hardness, chewiness and cooking loss than boiled meats. In total of 1608 proteins were identified and 103 proteins exhibited significant difference (fold change > 1.5, P < 0.05). These DAPs mainly involved in protein structure, metabolic enzyme, protein turnover and oxidation stress. ALDOC, PVALB, PPP1R14C, AMPD1, CRYAB and SOD1 were validated as potential indicators of color variations in cooked meat. CFL1, COL1A1, COL3A1, RTN4, NRAP, NT5C3A, and SOD1 might be potential biomarker for texture changes of cooked meats. Moreover, these validated proteins exhibited significant (P < 0.05) correlation with cooking loss and could be serve as candidate predictors for cooking loss changes of meats in different cooking procedures.

Freezing of meat and aquatic food: Underlying mechanisms and implications on protein oxidation

Over the recent decades,protein oxidation in muscle foods has gained increasing research interests as it is known that protein oxidation can affect eating quality and nutritional value of meat and aquatic products. Protein oxidation occurs during freezing/thawing and frozen storage of muscle foods, leading to irreversible physicochemical changes and impaired quality traits. Controlling oxidative damage to muscle foods during such technological processes requires a deeper understanding of the mechanisms of freezing-induced protein oxidation. This review focus on key physicochemical factors in freezing/thawing and frozen storage of muscle foods, such as formation of ice crystals, freeze concentrating and macromolecular crowding effect, instability of proteins at the ice-water interface, freezer burn, lipid oxidation, and so on. Possible relationships between these physicochemical factors and protein oxidation are thoroughly discussed. In addition, the occurrence of protein oxidation, the impact on eating quality and nutrition, and controlling methods are also briefly reviewed. This review will shed light on the complicated mechanism of protein oxidation in frozen muscle foods.