Analysis of Proteins Associated with Quality Deterioration of Grouper Fillets Based on TMT Quantitative Proteomics during Refrigerated Storage

Effect of liquid nitrogen freezing pretreatment on the meat quality of gazami crab (Portunus trituberculatus) during frozen storage

Liquid nitrogen freezing (LNF) pretreatment is an effective means of maintaining seafood quality during frozen storage. To improve the meat quality of gazami crab (Portunus trituberculatus) during frozen storage, this study investigated the effects of LNF temperatures on the meat quality of gazami crab. Fresh crab was pre-treated with different LNF temperatures (-60 °C, -80 °C, -100 °C, -120 °C), and then freeze in refrigerator at -18 °C. The changes in protein structure and meat quality of gazami crab during long-term frozen storage were measured. The results showed that -100 °C LNF more effectively inhibited the oxidative deterioration of crab meat during storage, which is lower than the optimal LNF temperature for shell free aquatic products such as fish, extending the shelf life of frozen gazami crab to 4 months. This study enriches the application parameters of LNF in freezing industry of crustacean aquatic products, providing guidance for exploring the optimal LNF temperature of aquatic products.

Laboratory-simulated marine heatwave enhances physiological damage to mussels exposed to titanium dioxide nanoparticles by disrupting the gut-hepatopancreas axis

The aggregation state of nano-TiO2 in the environment is altered under marine heatwaves (MHWs), thus affecting its bioavailability and toxicity to the marine organisms. Here, we investigated the toxic mechanisms and effects of nano-TiO2 on gut-hepatopancreas axis health of Mytilus coruscus exposed to 25 and 250 μg/L of nano-TiO2 under laboratory-simulated MHW. Compared with the control conditions or post-MHW cooling phase, prolonged MHW exposure significantly inhibited digestive function, decreased immune-related enzymes activities, and caused neurotoxicity in the mussels. 16S rRNA analysis demonstrated that high concentration nano-TiO2 and combined exposures decreased the abundance of Bacteroidota while increased the Proteobacteria. Additionally, the elevated pro-inflammatory bacteria released endotoxin lipopolysaccharide (LPS), which activated Toll-like receptor 4 (TLR-4) in the hepatopancreas and induced hepatopancreatic inflammation by downregulating nuclear factor-kappa B (NF-κB) signaling pathway and detoxification-related genes. Furthermore, nano-TiO2 and MHW exposure dysregulated the glutathione system, decreased the levels of antioxidation-related genes, and induced the accumulation of ROS and lipid peroxide (LPO) contents, thus causing severe oxidative damage and hepatopancreatic cell apoptosis. These findings demonstrate that nano-TiO2 and MHW induce hepatopancreatic inflammation and cell damage, which are strongly associated with the gut lesions and disrupted gut-hepatopancreas axis homeostasis.

Effects of different slaughtering methods on the biochemical characteristics and quality changes of tilapia (Oreochromis niloticus) during cold storage

Inappropriate slaughter methods can lead to differences in fish quality. In the past few years, few studies have focused on the effects of different slaughter methods on the postmortem effects of tilapia, especially the cold storage of tilapia after slaughter. The aim of this study was to investigate the effects of different slaughter methods on the biochemical characteristics and quality changes of tilapia during cold storage. In terms of blood and plasma parameters, the CS sample had lower levels of lactate dehydrogenase (LDH), cortisol (COR), and glucose (GLU) than the other samples. The results of K-value and FAAs showed that CS and ASCN groups were beneficial to prolong the freshness life of tilapia during cold storage. The texture properties of CS group were better. In summary, group CS is more conducive to prolonging the fresh life of refrigerated tilapia and is a recommended method of slaughter.

Knockdown of the ZcVgR Gene Alters the Expression of Genes Related to Reproduction and Lifespan in Zeugodacus cucurbitae (Coquillett) Under Extreme Heat Conditions

Zeugodacus cucurbitae (Coquillett) is an important migratory vegetable pest. Previous research has demonstrated that short-term high temperatures induce differential expression of the vitellogenin receptor (ZcVgR) gene, reducing the number of eggs laid and the lifespan of female Z. cucurbitae. In this paper, we used Tandem Mass Tags (TMT) quantitative proteomics and Illumina high-throughput sequencing to determine the proteomic and transcriptomic information of female Z. cucurbitae after siRNA-mediated silencing of the target gene (ZcVgR) to gain a comprehensive understanding of the molecular mechanism of this gene in the regulation of reproduction and lifespan. The findings demonstrated that following the target gene's silencing, the ZcVgR gene's transcriptional expression was significantly downregulated, and there was no significant difference in protein level. The transcriptome and proteome had a low correlation; when the ZcVgR gene was silenced, vitellogenin-1 (ZcVg1), juvenile hormone epoxide hydrolase (JHEH), troponin C (TnC), heat shock protein 70 (HSP70), and other related genes were downregulated at the transcriptional level. By silencing the ZcVgR gene, transcriptionally level immune-related pathways were activated and energy metabolism-related pathways were inhibited; protein-level glycometabolism and phagosome pathways were activated, while phototransduction-fly and autophagy-animal pathways were inhibited. The findings of this study might offer a theoretical foundation for integrated management of Z. cucurbitae in the summertime.

Quality changes in gazami crab (Portunus trituberculatus) during refrigeration

Gazami crab (Portunus trituberculatus) is prone to spoilage during storage and transportation. More research is needed to determine how to reliably show its freshness and explain the mechanism of quality deterioration. We hypothesized that proteins extracted from crabs can be biomarkers to detect crab muscle quality changes. This work used physicochemical and proteomic approaches to investigate protein biomarkers and molecular mechanisms driving changes in gazami crab muscle quality after long-term refrigeration. It was shown that 66 differentially abundant proteins (DAPs) were closely associated with pH and texture and can be used as biomarkers to assess crab muscle freshness. According to bioinformatics studies, ribosomes and autophagy were significant mechanisms in crab rotting. These findings provided new concepts and a theoretical foundation for evaluating the freshness of refrigerated gazami crab and help uncover the molecular mechanism of its quality deterioration.

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.

RNA-Seq analysis of the pyloric caecum, liver, and muscle reveals molecular mechanisms regulating fillet color in rainbow trout

BACKGROUND

The characteristic pink-reddish color in the salmonids fillet is an important, appealing quality trait for consumers and producers. The color results from diet supplementation with carotenoids, which accounts for up to 20-30% of the feed cost. Pigment retention in the muscle is a highly variable phenotype. In this study, we aimed to understand the molecular basis for the variation in fillet color when rainbow trout (Oncorhynchus mykiss) fish families were fed an Astaxanthin-supplemented diet. We used RNA-Seq to study the transcriptome profile in the pyloric caecum, liver, and muscle from fish families with pink-reddish fillet coloration (red) versus those with lighter pale coloration (white).

RESULTS

More DEGs were identified in the muscle (5,148) and liver (3,180) than in the pyloric caecum (272). Genes involved in lipid/carotenoid metabolism and transport, ribosomal activities, mitochondrial functions, and stress homeostasis were uniquely enriched in the muscle and liver. For instance, the two beta carotene genes (BCO1 and BCO2) were significantly under-represented in the muscle of the red fillet group favoring more carotenoid retention. Enriched genes in the pyloric caecum were involved in intestinal absorption and transport of carotenoids and lipids. In addition, the analysis revealed the modulation of several genes with immune functions in the pyloric caecum, liver, and muscle.

CONCLUSION

The results from this study deepen our understanding of carotenoid dynamics in rainbow trout and can guide us on strategies to improve Astaxanthin retention in the rainbow trout fillet.

Use of Tandem Mass Spectrometry Quantitative Proteomics to Identify Potential Biomarkers to Follow the Effects of Cold and Frozen Storage of Muscle Tissue of Litopenaeus vannamei

L. vannamei has become one of the most productive species. However, it is susceptible to microbial contamination during fishing, transportation, and storage, which can lead to spoilage and quality deterioration. This study investigates the relationship between changes in the proteome of Litopenaeus vannamei (L. vannamei) muscle and quality characteristics during low-temperature storage using the tandem mass spectrometry technology of quantitative proteomics strategy. The differential expression of proteins under cold storage (4 °C, CS), partial slight freezing (-3 °C, PFS), and frozen storage (-18 °C, FS) conditions was compared with the fresh group (CK), resulting in 1572 proteins identified as differentially expressed. The purpose of this research is to identify potential biochemical markers by analyzing quality changes and relative differential proteins through searches in the UniProt database, Gene Ontology database, and Genome Encyclopedia. Correlation analysis revealed that seven DEPs were significantly related to physical and chemical indicators. Bioinformatics analysis demonstrated that most DEPs are involved in binding proteins, metabolic enzymes, and protein turnover. Additionally, some DEPs were identified as potential biomarkers for muscle decline. These findings contribute to understanding the mechanism of freshness decline in L. vannamei under low-temperature storage and the changes in muscle proteome.

TMT-Based Quantitative Proteomics Analyses Reveal the Antibacterial Mechanisms of Anthocyanins from Aronia melanocarpa against Escherichia coli O157:H7

Aronia melanocarpa anthocyanins (AMAs), as natural plant extracts, can control pathogens and are attracting increasing attention. In this study, a tandem mass tag (TMT) quantitative proteomics method combined with multiple reaction monitoring (MRM) was used to explore the antibacterial mechanism of AMAs against Escherichia coli at the protein level. The results showed that 1739 proteins were identified in E. coli treated with AMAs, of which 628 were altered, including 262 downregulated proteins and 366 upregulated proteins. Bioinformatics analysis showed that these differentially expressed proteins have different molecular functions and participate in different molecular pathways. AMAs can affect E. coli protein biosynthesis, DNA replication and repair, oxidative stress response, peptidoglycan biosynthesis, and homeostasis. These pathways induce morphological changes and cell death. The results of this study help understand the molecular mechanism of the inhibitory effect of AMAs on food-borne pathogens and provide a reference for further development of plant-derived antimicrobial agents.

Transcriptome analysis reveals acclimation responses of pearl oysters to marine heatwaves

Marine heatwaves (MHWs) are weather-timescale extreme events in the oceans and can have devastating effects on marine bivalves and ecosystems they support, with considerable socio-economic consequences. Yet, the extent to which marine bivalves have the capacity to acclimate and adapt to MHWs remains unknown. Understanding molecular responses to MHWs is imperative to develop strategies for conservation of ecologically and economically important marine organisms. Here, using RNA-Seq, we investigate how various MHWs scenarios elicit molecular changes in threatened and vulnerable pearl oysters, Pinctada maxima (Jameson). Acute exposure of MHWs - mimicked by rapid increases of seawater temperature from 24 °C to 28 °C and 32 °C, respectively - significantly affected the expression levels of metabolic and immune-related genes, with thermal stress-responsive genes especially like HSP20, HSP70 and HSP90 being remarkably up-regulated. Following repeat exposure to MHWs, encouragingly, pearl oysters exhibited evident acclimation responses, as best exemplified by significantly lowered expression levels of key stress-responsive genes involved in metabolism and immunity in comparison to those observed during acute exposure. Findings of the present study provide a better understanding of molecular processes underpinning the acclimation and adaptation of marine bivalves to MHWs in the context of climate change.

A berberine hydrochloride-carboxymethyl chitosan hydrogel protects against Staphylococcus aureus infection in a rat mastitis model

Staphylococcus aureus (S. aureus) is the major pathogen responsible for mastitis in dairy cows, an important threat to their health, but prevention of S. aureus infection of the mammary gland remains challenging. Berberine hydrochloride (BH), a naturally occurring phytochemical, exhibits a wide range of activities, including antibacterial effects on S. aureus. In this study, we prepared a novel berberine hydrochloride-carboxymethyl chitosan hydrogel (BH-CMCH) with excellent thermosensitivity, injectability and in vitro antibacterial activity. In a rat model of mastitis induced by S. aureus, mammary duct injection of BH-CMCH reduced the bacterial load in infected mammary gland tissue and protected the tissue from damage from infection. In addition, proteomics analysis showed that mammary duct injection of BH-CMCH enhanced autolysosome degradation and promoted the innate immune response by activating the lysosomal pathway and up-regulating related significantly differentially expressed proteins (SDEPs). Taken together, the findings support the potential of BH-CMCH as an antibacterial agent against S. aureus-induced mastitis.

Response mechanism of ♀ Epinephelus fuscoguttatus × ♂ Epinephelus lanceolatus under low-temperature and waterless stresses using TMT proteomic analysis

♀Epinephelus fuscoguttatus × ♂Epinephelus lanceolatus, a hybrid grouper created from artificial breeding, has been widely developed over the past decades. However, the study focusing on lukewarm high-protein-content fish species using advanced techniques has rarely been reported. In this work, the TMT (tandem mass tag)-assisted technique was employed to explore its differentially expressed proteins and response mechanisms under low-temperature dormant and waterless stresses. Our findings suggest that 162 and 258 differentially expressed proteins were identified under low-temperature dormant and waterless stresses, respectively. The waterless preservation treatment further identifies 93 differentially expressed proteins. The identified proteins are categorized and found to participate in lipid metabolism, glycometabolism, oxidative stress, immune response, protein and amino acid metabolism, signal transduction, and other functions. Accordingly, the factors that affect the response mechanisms are highlighted to provide new evidences at protein level.

Unraveling Admixture, Inbreeding, and Recent Selection Signatures in West African Indigenous Cattle Populations in Benin

The Dwarf Lagune and the Savannah Somba cattle in Benin are typical representatives of the endangered West African indigenous Shorthorn taurine. The Lagune was previously exported to African and European countries and bred as Dahomey cattle, whereas the Somba contributed to the formation of two indigenous hybrids known as Borgou and Pabli cattle. These breeds are affected by demographic, economic, and environmental pressures in local production systems. Considering current and historical genomic data, we applied a formal test of admixture, estimated admixture proportions, and computed genomic inbreeding coefficients to characterize the five breeds. Subsequently, we unraveled the most recent selection signatures using the cross-population extended haplotype homozygosity approach, based on the current and historical genotypes. Results from principal component analyses and high proportion of Lagune ancestry confirm the Lagune origin of the European Dahomey cattle. Moreover, the Dahomey cattle displayed neither indicine nor European taurine (EUT) background, but they shared on average 40% of autozygosity from common ancestors, dated approximately eight generations ago. The Lagune cattle presented inbreeding coefficients larger than 0.13; however, the Somba and the hybrids (Borgou and Pabli) were less inbred (≤0.08). We detected evidence of admixture in the Somba and Lagune cattle, but they exhibited a similar African taurine (AFT) ancestral proportion (≥96%) to historical populations, respectively. A moderate and stable AFT ancestral proportion (62%) was also inferred for less admixed hybrid cattle including the Pabli. In contrast, the current Borgou samples displayed a lower AFT ancestral proportion (47%) than historical samples (63%). Irrespective of the admixture proportions, the hybrid populations displayed more selection signatures related to economic traits (reproduction, growth, and milk) than the taurine. In contrast, the taurine, especially the Somba, presented several regions known to be associated with adaptive traits (immunity and feed efficiency). The identified subregion of bovine leukocyte antigen (BoLA) class IIb (including DSB and BOLA-DYA) in Somba cattle is interestingly uncommon in other African breeds, suggesting further investigations to understand its association with specific adaptation to endemic diseases in Benin. Overall, our study provides deeper insights into recent evolutionary processes in the Beninese indigenous cattle and their aptitude for conservation and genetic improvement.

Effects of ultrasound on the thawing of quick-frozen small yellow croaker (Larimichthys polyactis) based on TMT-labeled quantitative proteomic

The effect of dual-frequency sequential ultrasonic thawing (DUT) on the quality of quick-frozen small yellow croaker was studied by TMT-labeled quantitative proteomic method. A total number of 75 proteins were identified as differentially abundant proteins (DAPs) in fish meat treated by DUT, while 72 DAPs were in flow water thawing (FWT). The Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis indicated that the DAPs in the significant enrichment pathway of DUT group were enzymes. Compared with FWT, DUT had a significant effect on the enzyme content. The correlation analyses indicated that 40 DAPs were related with the quality traits. The 11 highly correlated DAPs are expected to be used as potential protein markers for texture profile analyses, color, thawing loss, water-holding capacity, and pH of thawed small yellow croaker quality. These results provide a further understanding of the quality stability of quick-frozen small yellow croaker treated by the DUT.

Proteins associated with quality deterioration of prepared chicken breast based on differential proteomics during refrigerated storage

BACKGROUND

Prepared chicken breast deterioration is a complex biochemical process, of which protein change is one of the main features. The present research focuses on the analysis of proteins related to the deterioration in quality of prepared chicken breast through differential proteomics analysis.

RESULTS

The physicochemical indexes of prepared chicken breast showed that quality gradually decreased at the second week of refrigerated storage, while the deterioration of chicken breast meat was obvious at the third week. Three key time points of quality change were determined to be at 0th, 2th and 5th week, respectively. In addition, 39 differential proteins were successfully identified using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Most of the identified proteins showed significant differences in expression at the three key points of storage, of which actin, myosin, α-1,4-glucan phosphorylase, phosphoglucomutase 1, heat shock protein β-1, tubulin β-7 chain and skeletal muscle type tropomodulin (fragment) were closely related to the quality deterioration of prepared chicken breast, and thus potential indicator proteins to evaluate the quality of chicken breast.

CONCLUSION

The current study indicated that the physicochemical quality of prepared breast notably changed during refrigerated storage. Three key time points of quality change in the storage process of prepared chicken breast were determined. Furthermore, differential proteomics identified the key proteins related to freshness, which provides a theoretical basis for exploring the mechanism of chicken breast deterioration. © 2020 Society of Chemical Industry.

Differential Proteomics Analysis of Penaeus vannamei Muscles with Quality Characteristics by TMT Quantitative Proteomics during Low-Temperature Storage

A tandem mass tag technology, based on the quantitative proteomics strategy, was applied to investigate the relationships between proteome changes of Penaeus vannamei (PNVN) muscles and quality characteristics during low-temperature storage. 506 proteins were found as differentially expressed proteins (DEPs) after 10 days of storage under treatments of refrigerated storage (5 °C), ice temperature storage (0 °C), and particle freezing storage (-3 °C) compared with a fresh group (0 day). In addition, Uniprot Knowledgebase (UniprotKB), Gene Ontology enrichment, and Kyoto Encyclopedia of Genes and Genomes were reported. Correlation analysis indicated that nine DEPs were significantly related to quality characteristics-pH, color, and texture. Bioinformatics analysis showed that most of DEPs were involved in binding proteins, metabolic enzyme, and protein turnover. Besides, several DEPs could be good candidate biomarkers of muscle decline. These results could help to further comprehend the proteome changes and mechanisms of the quality decline of PNVN muscles during low-temperature storage.

Effect of vacuum impregnated fish gelatin and grape seed extract on moisture state, microbiota composition, and quality of chilled seabass fillets

The effect of fish gelatin (FG) and grape seed extract (GSE) on microbiota composition and moisture state of fish was unexplored. Herein, this study aimed to evaluate the single and combined (FGG) effects on seabass during storage (4 °C) with assistant of vacuum impregnation and to elucidate the underlying preservative mechanism. As suggested by low-field NMR and magnetic resonance imaging, FGG-treated seabass presented higher water holding capacity by controlling transformation from immobilised to free water. Moreover, the total viable count and spoilage bacteria were reduced by > 1 log CFU/g as compared to the control. Changes in microbial flora analysed using high throughput sequencing further indicated that GSE contributed to the notably suppressed growth of Pseudomonas. Also, the accumulation of biogenic amines especially putrescine was decreased (over 0.5-fold) under the combination treatment as compared to the control (P < 0.05). The results suggest that FGG is promising for seabass preservation.

COL1A1 as a potential new biomarker and therapeutic target for type 2 diabetes

Type 2 diabetes (T2D) is a public health problem with a rising incidence worldwide. In this study, a potential new biomarker for T2D and mechanisms underlying the hypoglycemic effects of Enteromorpha prolifera oligosaccharide were investigated. Tandem mass tag labeling with LC-MS/MS was used to identify the differentially expressed proteins (DEPs) between the jejunum of diabetic rats and control rats. Correlations between glycometabolic parameters and DEPs were revealed by a network analysis. The expression levels of target genes in key metabolic pathways were further evaluated to identify candidate biomarkers. Among 6810 total proteins, approximately 88 % were quantified, of which 148 DEPs with a fold change of <0.83 or>1.2 and a corrected p-value of <0.05 were identified. A KEGG enrichment analysis indicated that the hypoglycaemic effects of E. prolifera oligosaccharide involved the PI3K/AKT and extracellular matrix receptor interaction signaling pathways. More importantly, Col1a1 was the most significant gene in the extracellular matrix receptor interaction pathway and was linked to hypoglycaemic activity for the first time. Thus, Col1a1 is a novel potential therapeutic target for alleviating T2D.

TMT-Based Quantitative Proteomics Analysis of the Fish-Borne Spoiler Shewanella putrefaciens Subjected to Cold Stress Using LC-MS/MS

Shewanella putrefaciens is a specific spoilage bacterium for fish during cold storage. To better understand the molecular mechanisms of cold stress adaptation of S. putrefaciens, tandem mass tag- (TMT-) based quantitative proteomic analysis was performed to detect the effects of cold stress on protein expression profiles in S. putrefaciens which had been cultivated at 4°C and 30°C, respectively. A total of 266670 peptide spectrum matching numbers were quantified proteins after data analysis. Of the 2292 proteins quantitatively analyzed, a total of 274 were found to be differentially expressed (DE) under cold stress compared with the nonstress control. By integrating the results of Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, 9 common KEGG terms were found notable for the cold-responsive proteins. Generally, the DE proteins involved in carbohydrate, amino acid, and fatty acid biosynthesis and metabolism were significantly upregulated, leading to a specific energy conservation survival mode. The DE proteins related to DNA repair, transcription, and translation were upregulated, implicating change of gene expression and more protein biosynthesis needed in response to cold stress.

Cucurbitacin E Chemosensitizes Colorectal Cancer Cells via Mitigating TFAP4/Wnt/β-Catenin Signaling

Chemoresistance and toxicity are the main obstacles that limit the efficacy of 5-fluorouracil (5-FU) in colorectal cancer (CRC) therapy. Hence, it is urgent to identify new adjuvants that can sensitize CRC cells to conventional chemotherapeutic approaches. Cucurbitacin E (CE) is a natural triterpenoid, widely distributed in dietary plants, and shows antitumor effects. Here, we report that CE enhances the sensitivity of CRC cells to chemotherapy via attenuating the expression of adenosine 5'-triphosphate (ATP)-binding cassette transporters ABCC1 and MDR1. Combined with CE-functionalized magnetite nanoparticles and gene ontology analysis, we found that CE-binding proteins may involve Wnt/β-catenin signaling. To validate the findings, β-catenin was upregulated in drug-resistant cell lines, and the synergistic effects of CE and chemotherapeutics were accompanied by the downregulation of β-catenin. Moreover, TFAP4 was identified as an intracellular target of CE. Remarkably, the combination of CE and 5-FU treatment attenuated β-catenin, MDR1, and ABCC1 expressions, while TFAP4 overexpression reversed their expressions by 2.68 ± 0.46-, 0.72 ± 0.44-, and 0.93 ± 0.21-fold, respectively. Thus, our results indicate that CE sensitizes CRC cells to chemotherapy by decreasing the TFAP4/Wnt/β-catenin signaling, suggesting that the dietary compound CE can be used as a chemosensitizing adjuvant for CRC treatment.

Staphylococcus aureus-induced proteomic changes in the mammary tissue of rats: A TMT-based study

Staphylococcus aureus is one of the most important pathogens causing mastitis in dairy cows. The objective of this study was to establish a rat model of mastitis induced by S. aureus infection and to explore changes in the proteomes of mammary tissue in different udder states, providing a better understanding of the host immune response to S. aureus mastitis. On day 3 post-partum, 6 rats were randomly divided into two groups (n = 3), with either 100 μL of PBS (blank group) or a S. aureus suspension containing 2×10⁷ CFU·mL⁻¹ (challenge group) infused into the mammary gland duct. After 24 h of infection, the rats were sacrificed, and mammary gland tissue was collected. Tandem mass tag (TMT)-based technology was applied to compare the proteomes of healthy and mastitic mammary tissues. Compared with the control group, the challenge group had 555 proteins with significant differences in expression, of which 428 were significantly upregulated (FC>1.2 and p<0.05) and 127 were downregulated (FC>0.83 and p<0.05 or p<0.01). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that upregulated differentially significant expressed proteins (DSEPs) were associated with mainly immune responses, including integrin alpha M, inter-α-trypsin inhibitor heavy chain 4, and alpha-2-macroglobulin. This study is the first in which a rat model of S. aureus-induced mastitis was used to explore the proteins related to mastitis in dairy cows by TMT technology, providing a model for replication of dairy cow S. aureus-induced mastitis experiments.

Eugenol-loaded chitosan emulsion holds the texture of chilled hairtail (Trichiurus lepturus) better: mechanism exploration by proteomic analysis

Eugenol-loaded chitosan emulsion (ELCE) has been proved to have an excellent antibacterial property.