Effect of baking on the structure and bioavailability of protein-binding zinc from oyster (Crassoetrea hongkongensis).

To compare the bioavailability of protein-binding zinc, we investigated the impact of baking on the structure of zinc-binding proteins. The results showed that zinc-binding proteins enriched in zinc with relative molecular weights distributed at 6 kDa and 3 kDa. Protein-binding zinc is predisposed to separate from proteins' interiors and converge on proteins' surface after being baked, and its structure tends to be crystalline. Especially -COO, -C-O, and -C-N played vital roles in the sites of zinc-binding proteins. However, baking did not affect protein-binding zinc's bioavailability which was superior to that of ZnSO4 and C12H22O14Zn. They were digested in the intestine, zinc-binding complexes that were easily transported and uptaken by Caco-2 cells, with transport and uptake rates as high as 62.15% and 15.85%. Consequently, baking can alter the conformation of zinc-binding proteins without any impact on protein-binding zinc's bioavailability which is superior to that of ZnSO4 and C12H22O14Zn.

Anti-Inflammatory Activity of Peptides from Ruditapes philippinarum in Lipopolysaccharide-Induced RAW264.7 Cells and Mice.

In our previous study, two peptides with favorable anti-inflammatory effects, Asp-Gln-Thr-Phe (DQTF) and Gly-Tyr-Thr-Arg (GYTR), were screened from Ruditapes philippinarum using an in vitro-in silico strategy. The present study aims to investigate the ameliorative effect of Ruditapes philippinarum peptides (RPPs) on acute inflammation and clarify the potential mechanism through in vitro and in vivo experiments. The anti-inflammatory effects of DQTF and GYTR were verified with a lipopolysaccharide (LPS)-induced RAW264.7 cell acute inflammation model and the anti-inflammatory effect of the enzymatic hydrolysates of Ruditapes philippinarum was explored in vivo using an LPS-induced acute inflammatory injury model in mice. The results show that DQTF and GYTR improved the morphology of LPS-injured cells and decreased the concentrations of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in LPS-induced cells. Moreover, the antioxidant enzyme activity in cells was markedly increased with DQTF and GYTR. The enzymatic hydrolysates of Ruditapes philippinarum were obtained with hydrolysis using pepsin-chymotrypsin-trypsin (PeCTHC) and pepsin-trypsin (PeTHC), respectively. PeCTHC and PeTHC significantly reduced pro-inflammatory cytokines and nitric oxide (NO) in the serum. Additionally, the blood indices and levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and malondialdehyde (MDA) in the livers of mice were markedly improved with RPPs administration. In conclusion, RPPs have preventive and protective effects on acute inflammation, with significant prospects for development in the field of functional foods.

Factors affecting local alveolar bone thickness in unilateral maxillary canine-lateral incisor transposition.

INTRODUCTION: This study aimed to use 3-dimensional data to investigate the factors affecting local alveolar bone thickness in unilateral maxillary canine-lateral incisor transposition. METHODS: Pretreatment cone-beam computed tomography data of 34 patients with unilateral maxillary canine-lateral transposition were imported into Dolphin Imaging software (version 11.8; Dolphin Imaging and Management Solutions, Chatsworth, Calif) for 3-dimensional reconstruction. The age, gender, and type of transposition at the beginning of treatment were recorded. The thickness and height of the transposed canine, the labiopalatal and distomedial distance from the transposed canine to the apex of the lateral incisor, the inclination of the transposed lateral incisor, the apical height of the lateral incisor, and the alveolar bone thickness in the apical plane were measured. Multiple linear regression analyses were applied to investigate the factors affecting alveolar bone thickness in the apical plane of the transposed lateral incisor. Two sample t test were applied to assess the difference of alveolar bone thickness in patients of different ages. RESULTS: The 10 boys and 24 girls had a mean age of 12.26 ± 2.34 years. In all 34 participants, the apical alveolar bone thickness of transposed lateral incisors was significantly higher than that of the unaffected side (P <0.05). Based on multiple regression analyses, factors associated with a wider alveolar bone thickness were as follows: age (ß = -0.237; P = 0.008), the labiopalatal distance from the transposed canine to the apex of the lateral incisor (ß = 0.675; P <0.001), and the inclination of the transposed lateral incisor (ß = 0.048; P = 0.032). Patients aged <11 years had significantly thicker alveolar bone than that of patients aged >11 years (P <0.05). CONCLUSIONS: Patients with younger age, greater lateral incisor inclination, and greater labiopalatal distance between canine and lateral incisor had more alveolar bone thickness. Early treatment permits tooth movement within the thicker alveolar bone.

Purification, Characterization, cDNA Cloning, and Bioinformatic Analysis of Zinc-Binding Protein from Magallana hongkongensis.

Oysters contain significant amounts of the zinc element, which may also be found in their proteins. In this study, a novel zinc-binding protein was purified from the mantle of the oyster Magallana hongkongensis using two kinds of gel filtration chromatograms. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that its molecular weight was approximately 36 kDa. The protein identified by the Q-Exactive mass spectrometer shared the highest sequence identity with carbonic anhydrase derived from Crassostrea gigas concerning amino acid sequence similarity. Based on homologous cloning and RACE PCR, the full-length cDNA of carbonic anhydrase from Magallana hongkongensis (designated as MhCA) was cloned and sequenced. The cDNA of MhCA encodes a 315-amino-acid protein with 89.74% homology to carbonic anhydrase derived from Crassostrea gigas. Molecular docking revealed that the two zinc ions primarily form coordination bonds with histidine residues in the MhCA protein. These results strongly suggest that MhCA is a novel zinc-binding protein in Magallana hongkongensis.

Carboxymethyl cellulose and carboxymethyl chitosan-based composite nanogel as a stable delivery vehicle for oyster peptides: Characterization, absorption and transport mechanism.

An oyster peptide (OPs)-loaded composite nanogel based on carboxymethyl cellulose and carboxymethyl chitosan (CMC@CMCS@OPs) was prepared, and the characterization, absorption and transport mechanism were further investigated. CMC@CMCS@OPs, a dense spherical microstructure with a diameter of ∼64 nm, which enhanced the thermal and digestive stabilities of individual OPs and improved its retention rate of hypoglycemic activity in vitro. The swelling response and in-vitro release profiles showed that CMC@CMCS@OPs could help OPs achieve targeted and controlled release in the intestine. In addition, CMC@CMCS@OPs had no cytotoxicity on Caco-2 cells, and its apparent permeability coefficients increased 4.70-7.45 times compared with OPs, with the absorption rate increased by 129.38 %. Moreover, the transcytosis of CMC@CMCS@OPs nanogel occurred primarily through the macropinocytosis pathway, endocytosis pathway and intestinal efflux transporter-mediated efflux. Altogether, these results suggested that CMC@CMCS@OPs nanogel could be as an effective OPs delivery device for enhancing its stability and absorption.

Purification and characterization of a novel immunoregulatory peptide from Sipunculus nudus L. protein.

This study aimed to purify and characterize immunoregulatory peptides from Sipunculus nudus L. and to explore the underlying mechanisms. Ultrafiltration, gel filtration chromatography, and reverse phase high-performance liquid chromatography (RP-HPLC) were used to purify the peptide following enzymatic hydrolysis. Rates of lymphocyte proliferation and phagocytosis as well as nitric oxide (NO) production levels were used as indicators of immunoregulatory activity to screen the fractions. The amino acid sequence of the peptide, designated as SNLP, was identified as Arg-Val-Lys-Gly-Lys-Ile-Leu-Ala-Lys-Arg-Leu-Asn (RVKGKILAKRLN) by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Treatment with the synthetic SNLP increased the proliferation and phagocytosis of RAW 264.7 macrophages and promoted the secretion of tumor necrosis factor-ɑ (TNF-α), interleukin-6 (IL-6), interleukin-1ß (IL-1ß), and NO levels. The mRNA levels of these cytokines and iNOS were also increased by SNLP. Our results provide preliminary evidence suggesting that SNLP acts as a dual immunomodulatory peptide with immunostimulatory and anti-inflammatory activities. In summary, SNLP derived from Sipunculus nudus L. is a potent immunoregulatory peptide and represents a potential functional food or immunoregulatory drug.

Optimization of a Novel Tyrosinase Inhibitory Peptide from Atrina pectinata Mantle and Its Molecular Inhibitory Mechanism.

In order to realize the multi-level utilization of marine shellfish resources and to develop the potential biological activity of processing by-products of Atrina pectinata, gelatin was extracted from the mantle and the potential whitening effect of its enzymatic peptides was explored. Taking tyrosinase inhibitory activity as the evaluation index, the enzyme hydrolysate process was optimized by response-surface methodology, and the optimal enzyme hydrolysate conditions were as follows: pH 5.82, 238 min enzyme hydrolysate time, and temperature of 54.5 °C. Under these conditions, the tyrosinase inhibition activity of Atrina pectinata mantle gelatin peptide (APGP) was 88.6% (IC50 of 3.268 ± 0.048 mg/mL). The peptides obtained from the identification were separated by ultrafiltration and LC-MS/MS, and then four new peptides were screened by molecular docking, among which the peptide Tyr-Tyr-Pro (YYP) had the strongest inhibitory effect on tyrosinase with an IC50 value of 1.764 ± 0.025 mM. The molecular-docking results indicated that hydrogen bonding is the main driving force for the interaction of the peptide YYP with tyrosinase. From the Lineweaver-Burk analysis, it could be concluded that YYP is inhibitory to tyrosinase and exhibits a mixed mechanism of inhibition. These results suggest that YYP could be widely used as a tyrosinase inhibitor in whitening foods and pharmaceuticals.

Recent advances in taste transduction mechanism, analysis methods and strategies employed to improve the taste of taste peptides.

Taste peptides are oligopeptides that enhance both aroma and taste of food, and they are classified into five categories based on their taste characteristics: salty, sour, umami, sweet, bitter, and kokumi peptide. Recently, taste peptides have attracted the attention of several fields of research in food science and commercial applications. However, research on taste receptors of taste peptides and their taste transduction mechanisms are not clearly understood and we present a comprehensive review about these topics here. This review covers the aspects of taste peptides perceived by their receptors in taste cells, the proposed transduction pathway, as well as structural features of taste peptides. Apart from traditional methods, molecular docking, peptidomic analysis, cell and animal models and taste bud biosensors can be used to explore the taste mechanism of taste peptides. Furthermore, synergistic effect, Maillard reaction, structural modifications and changing external environment are employed to improve the taste of taste peptides. Consequently, we discussed the current challenges and future trends in taste peptide research. Based on the summarized developments, taste peptides derived from food proteins potentially appear to be important taste substances. Their applications meet the principles of "safe, nutritious and sustainable" in food development.

Effects of albiflorin on oxidative stress and inflammatory responses in rats with acute spinal cord injury.

INTRODUCTION: Oxidative stress and inflammatory responses are often the predominant detrimental factors associated with spinal cord injury (SCI). This study investigates the potential therapeutic effects of albiflorin (AF) on alleviating inflammation and oxidative stress in the rat model with SCI. METHODS: Initially, the behavior of SCI-induced rats is examined by Basso-Beattie-Bresnahan score and the inclined plane examination. Then, the immunohistochemical staining of inflammasome-related protein (for instance, NACHT, LRR, and PYD domains-containing protein 3, NLRP3) is performed in combination with enzyme-linked immunosorbent assay (ELISA) of corresponding proinflammatory factors to assess the immunomodulatory effects of AF. Further, the markers involved in oxidative stress are examined by ELISA and western blot analysis analyses. RESULTS: These findings indicated that AF could alleviate motor dysfunction and the loss of neuron cells in SCI-induced rats. Mechanistically, AF could attenuate the inflammatory responses by reducing oxidative stress and activating nuclear erythroid-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway in SCI rats. Depleting the antioxidant capacity by inhibiting glutathione biosynthesis could counteract the anti-inflammatory activity of AF in SCI rats. CONCLUSIONS: Together, our data suggested that AF could serve as a potential therapeutic agent against the aggravation of SCI in rats.

Functional, physicochemical, and structural properties of the hydrolysates derived from the abalone (Haliotis discus subsp hannai Ino) foot muscle proteins.

This study was conducted to investigate functional, physicochemical, and structural properties of abalone foot muscle proteins (AFPs) and their hydrolysates (HAFPs) obtained using animal protease (HA), papain (HPP), and Protamex® (HP) at different time points. The HA-hydrolysate obtained after 0.5 h of treatment demonstrated the highest solubility at pH 7.0 (84.19%); the HPP-hydrolysate at 4 h exhibited the highest degree of hydrolysis (11.4%); the HPP-hydrolysate at 0.5 h had the highest oil holding capacity (2.62 g/g) and emulsion stability index (39.73 min), and the HP-hydrolysate at 4 h had the highest emulsifying activity index (93.23 m2/g) and foaming stability (91.45%); Regarding the physicochemical properties, the HPP-hydrolysates revealed the largest particle size, higher absolute zeta potential, and superior interfacial activity. Structural characterization demonstrated the enzymolysis-based changes in the composition and the secondary structure of the AFPs. These results provide practical support for the theoretical basis of the use of AFPs as a source of nutritive proteins in the food industry.

Morphometric evaluation of alveolar bone after orthodontic treatment of multiple impacted teeth in the unilateral maxillary anterior region.

INTRODUCTION: This study aimed to investigate the height and thickness of alveolar bone by cone-beam computed tomography imaging after orthodontic treatment in the unilateral maxillary anterior region and speculate on reasons for the difference in alveolar bone morphology. METHODS: This study selected 11 patients (3 males and 8 females; mean age, 9.42 ± 1.45 years). Cone-beam computed tomography was performed for these 11 patients before and after treatment using Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif). Labial and palatal alveolar bone thickness (BT) at root apices and different levels along the roots and loss of alveolar bone height was measured for each impacted tooth and its contralateral homonymous tooth. RESULTS: After orthodontic therapy, all 3 impacted anterior teeth had different degrees of loss of labial alveolar bone height compared with the normal side (central incisor: -1.5 mm, P <0.005; lateral incisor: -1.06 mm, P <0.01; canine: -0.59 mm, P < 0.01). The lateral incisors also showed palatal alveolar bone height loss compared with the unaffected side (-0.8 mm, P <0.005). Alveolar BT at root apices of impacted canines was 1.14 mm thicker than the normal side (P <0.005). Central and lateral incisors were similar to the normal side. The thickness of the alveolar bone at 8, 10, and 12 mm of the impacted canine position was still larger than that on the healthy side, whereas the difference in average thickness between the healthy and affected side had been significantly reduced compared with pretreatment measurements. CONCLUSIONS: There is satisfactory retention of alveolar bone height in canines after orthodontic treatment; however, alveolar bone loss is slightly worse at central and lateral incisors. Retention of alveolar BT was normal for impacted anterior teeth, whereas excess apical alveolar BT at the canines, although still present, was substantially less significant than had been observed before treatment.

Effect of Drying Process on the Formation of the Characteristic Flavor of Oyster (Crassostrea hongkongensis).

Oysters are nutritious and tasty but difficult to store. Drying can extend the storage period of oysters and give them a unique flavor. In this study, the effects of four drying procedures, namely, vacuum freeze drying (VFD), vacuum drying (VD), natural sun-drying (NSD), and hot air drying (HAD), on the flavor characteristics of oysters (Crassostrea hongkongensis) were investigated using blanched oysters as a control (CK). Results showed that HAD produced more free amino acids than the other methods, but VFD retained the most flavor nucleotides. Compared with cold drying (VFD), hot drying (VD, NSD, and HAD) increased the abundance of organic acids, betaine, and aroma substances. Glutamic acid, alanine, AMP, hexanal, octanal, heptanal, (E, E)-2,4-heptadienal, (E)-2-decenal, nonanal, etc., are defined as the characteristic flavor compounds of dried oysters, with umami, sweet, green, fatty, and fruity aromas being the main organoleptic attributes of dried oysters. Glutamic acid, glycine, betaine, IMP, pentanal, ethyl heptanoate, (E, Z)-2,4-nonadienal, 1-octen-3-one, 2-hexenal, 2-octenal, hexanal, decanal were defined as markers to distinguish different drying methods. Overall, HAD showed improved flavor qualities and characteristics and was better suited for the highly commercialized production of dried oysters.

Pediatric myelin oligodendrocyte glycoprotein antibody-associated disease in southern China: analysis of 93 cases.

Objective: To study the clinical features of children diagnosed with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) in southern China. Methods: Clinical data of children diagnosed with MOGAD from April 2014 to September 2021 were analyzed. Results: A total of 93 children (M/F=45/48; median onset age=6.0 y) with MOGAD were involved. Seizures or limb paralysis was the most common onset or course symptom, respectively. The most common lesion locations in brain MRI, orbital MRI, and spinal cord MRI were basal ganglia and subcortical white matter, the orbital segment of the optic nerve, and the cervical segment, respectively. ADEM (58.10%) was the most common clinical phenotype. The relapse rate was 24.7%. Compared with the patients without relapse, relapsed patients had a longer interval from onset to diagnosis (median: 19 days VS 20 days) and higher MOG antibody titer at onset (median: 1:32 VS 1:100) with longer positively persistent (median: 3 months VS 24 months). All patients received IVMP plus IVIG at the acute phase, and 96.8% of patients achieved remission after one to three courses of treatment. MMF, monthly IVIG, and maintaining a low dose of oral prednisone were used alone or in combination as maintenance immunotherapy for relapsed patients and effectively reduced relapse. It transpired 41.9% of patients had neurological sequelae, with movement disorder being the most common. Compared with patients without sequelae, patients with sequelae had higher MOG antibody titer at onset (median: 1:32 VS 1:100) with longer persistence (median: 3 months VS 6 months) and higher disease relapse rate (14.8% VS 38.5%). Conclusions: Results showed the following about pediatric MOGAD in southern China: the median onset age was 6.0 years, with no obvious sex distribution difference; seizure or limb paralysis, respectively, are the most common onset or course symptom; the lesions of basal ganglia, subcortical white matter, the orbital segment of the optic nerve, and cervical segment were commonly involved in the CNS MRI; ADEM was the most common clinical phenotype; most had a good response to immunotherapy; although the relapse rate was relatively high, MMF, monthly IVIG and a low dose of oral prednisone might effectively reduce relapse; neurological sequelae were common, and possibly associated with MOG antibody status and disease relapse.

Effects of cold atmospheric plasma on endogenous enzyme activity and muscle protein oxidation in Trachinotus ovatus.

In this study, we investigated the effects of cold atmospheric plasma (CAP) technology on endogenous enzyme characteristics and muscle protein properties of the golden pomfret (Trachinotus ovatus) under different treatment power and time conditions. Results showed that the enzymatic activity of cathepsin B, L, and calpain in crude protease extracts (CPE) decreased significantly as the treatment power and treatment time of CAP increased (p < 0.05). Oxidative degradation of the CPE after exposure to CAP resulted in significant changes in the structure, total sulfhydryl, and carbonyl content of the CPE (p < 0.05). CAP of an appropriate intensity resulted in significant improvements in the color parameters, hydration properties, and textural property parameters of muscle proteins (p < 0.05). These results suggest that CAP, as a non-thermophysical modification technique, can inhibit the activity of endogenous enzymes as well as alter the protein function in food.

Effect of ultrasonic power on the stability of low-molecular-weight oyster peptides functional-nutrition W1/O/W2 double emulsion.

Ultrasonic-assisted treatment is an eco-friendly and cost-effective emulsification method, and the acoustic cavitation effect produced by ultrasonic equipment is conducive to the formation of stable emulsion. However, its effect on the underlying stability of low-molecular-weight oyster peptides (LOPs) functional-nutrition W1/O/W2 double emulsion has not been reported. The effects of different ultrasonic power (50, 75, 100, 125, and 150 W) on the stability of double emulsions and the ability to mask the fishy odor of LOPs were investigated. Low ultrasonic power (50 W and 75 W) treatment failed to form a well-stabilized double emulsion, and excessive ultrasound treatment (150 W) destroyed its structure. At an ultrasonic power of 125 W, smaller particle-sized double emulsion was formed with more uniform distribution, more whiteness, and a lower viscosity coefficient. Meanwhile, the cavitation effect generated by 125 W ultrasonic power improved storage, and oxidative stabilities, emulsifying properties of double emulsion by reducing the droplet size and improved sensorial acceptability by masking the undesirable flavor of LOPs. The structure of the double emulsion was further confirmed by optical microscopy and confocal laser scanning microscopy. The ultrasonic-assisted treatment is of potential value for the industrial application of double emulsion in functional-nutrition foods.

Oyster Peptide-Zinc Complex Ameliorates Di-(2-ethylhexyl) Phthalate-Induced Testis Injury in Male Mice and Improving Gut Microbiota.

Di-(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer, which can cause damage to male reproductive organs, especially the atrophy of the testis. Meanwhile, DEHP can also lead to a decrease in testicular zinc content, but the role of zinc remains unclear. This study aims to prepare oyster peptide-zinc complex (OPZC) to alleviate DEHP-induced reproductive damage in mice. OPZC was successfully obtained through electron microscopy, X-ray diffraction, and thermogravimetric analysis, with stable structure and high water-solubility. Low dose oyster peptide-zinc complex (OPZCL) significantly reduced the reproductive damage caused by DEHP in mice. Further research had shown that OPZCL restored the content of serum hormones and the activity of oxidative stress kinases to normal, while also normalizing testicular zinc and selenium levels. In addition, it also recovered the disorder of gut microbiota, reduced the proportion of Bacteroides, increased the abundance of Ligilactobacillus, and restored the proportion of Acidobacteriota, Chloroflexi, and Proteobacteria. Therefore, OPZCL can relieve the reproductive damage caused by DEHP in mice by restoring testicular zinc homeostasis and the composition of intestinal microbiota, indicating that OPZCL has a potential protective effect on male reproductive health.

LC-MS and Transcriptome Analysis of Lipopeptide Biosynthesis by Bacillus velezensis CMT-6 Responding to Dissolved Oxygen.

Dissolved oxygen (DO) is an key factor for lipopeptide fermentation. To better understand the link between oxygen supply and lipopeptide productivity in Bacillus velezensis CMT-6, the mechanism of DO on the synthesis of antimicrobial lipopeptides by Bacillus velezensis CMT-6 was examined. The production of surfactin and iturin of CMT-6 was detected by liquid chromatography-mass spectrometer (LC-MS) under different DO conditions and transcriptome analysis was performed. At 100 and 200 rpm, the lipopeptides productions were 2753.62 mg/L and 3452.90 mg/L, respectively. There was no significant change in the yield of iturin but that of surfactin increased by 64.14%. Transcriptome analysis revealed that the enriched differential genes were concentrated in the GO term of oxidation-reduction process. The marked enrichment of the lipopeptides synthesis pathway, including microbial metabolism in diverse environments and carbon metabolism in the two-component system, were observed. More importantly, the expression levels of the four surfactin synthetase genes increased at higher DO, however, the iturin synthetase gene expression did not. Furthermore, modular surfactin synthetase was overexpressed (between 9- and 49-fold) at 200 rpm but not at 100 rpm, which is suggestive of efficient surfactin assembly resulting in surfactin overproduction. This study provides a theoretical basis for constructing engineering strains with high lipopeptide production to adapt to different DO.

The Spatial Distribution Patterns, Physicochemical Properties, and Structural Characterization of Proteins in Oysters (Crassostrea hongkongensis).

Protein content, a vital component determining the nutritional quality of oysters, is unevenly distributed in different parts of oyster. In this study, the spatial distribution (visceral mass, mantle, gill, and adductor) patterns and structural characteristics of proteins, including water-soluble proteins (WSP), salt-soluble proteins (SSP), acid-soluble proteins (ASP) and alkali-soluble proteins (ALSP) of oysters (Crassostrea hongkongensis) were investigated with the amino acid analyzer, circular dichroism spectroscopy (CD), fourier transform infrared spectroscopy (FTIR), and fluorescence spectroscopy. The results showed that oyster proteins were mainly distributed in the visceral mass and mantle. The protein composition was WSP, SSP, ALSP, and ASP in descending order, which conformed to the ideal amino acid pattern. Variations in secondary structure, molecular weight distribution, and thermal denaturation temperatures of the oyster proteins were observed. SSP had wider bands (16-270 kDa) than those of ASP (30-37 kDa) and ALSP (66-270 kDa). Among the four proteins, the SSP of the mantle showed the highest thermal stability (87.4 °C), while ALSP of the adductor muscle had the lowest the lowest the peak denaturation temperature (Tm) (53.8 °C). The proportions of secondary structures in oyster proteins were different, with a higher proportion of solid protein ß-folds, and the exposure of aromatic amino acid residues and disulfide bonds and the microenvironment in which they were located were also different.

Investigation of the In Vivo, In Vitro, and In Silico Wound Healing Potential of Pinctada martensii Purified Peptides.

Previous studies found that both oral and topical administration of enzymatic digestion products < 3 K Da ultrafiltration fractions of Pinctada martensii mantle (PMPs) had pro-healing effects. Thus, we further purified them by Sephadex-G25 and screened them by cellular assays to obtain Pinctada martensii purified peptides (PMPPs). In this study, we explored the mechanism of PMPPs on wound healing by in vivo, in vitro, and in silico experiments. LC-MS/MS results showed that PMPPs consisted of 33 peptides with molecular weights ranging from 758.43 to 2014.04 Da, and the characteristic peptide was Leu-Asp. The results of cellular assays showed that PMPPs promoted the proliferation of human skin fibroblasts (HSF) (135%) and human immortalized keratinocyte (HaCaT) cells (125%) very significantly at 12.5 µg/mL. The in vivo results showed that PMPPs could achieve scarless healing by inhibiting the inflammatory response, accelerating the epithelialization process, and regulating collagen I/III ratio. The optimal peptide sequence FAFQAEIAQLMS of PMPPs was screened for key protein receptors in wound healing (EGFR1, FGFR1, and MMP-1) with the help of molecular docking technique, which also showed to be the key pro-healing active peptide sequence. Therefore, it may provide a therapeutic strategy with great potential for wound healing.

Theragra chalcogramma Hydrolysates, Rich in Gly-Leu-Pro-Ser-Tyr-Thr, Exerts Anti-Photoaging Potential via Targeting MAPK and NF-κB Pathways in SD Rats.

Previous studies have revealed that excessive exposure to UV irradiation is the main cause of skin photoaging and the signaling pathways of MAPK and NF-κB are involved in this progression. The present study aims to investigate the anti-photoaging effects of low molecular weight hydrolysates from Theragra chalcogramma (TCH) and to clarify the underlying mechanism. The degradation of mechanical barrier functions in photoaged skin was substantially ameliorated after TCH administration; meanwhile, TCH significantly elevated the antioxidant capacity and suppressed the over-production of inflammatory cytokine IL-1ß. Moreover, the histopathological deteriorations such as epidermal hyperplasia and dermal loss were significantly alleviated, along with the increase in procollagen type I content and decrease in MMP-1 activity (p < 0.05). Furthermore, TCH effectively blocked the MAPK and NF-κB signaling pathways through inhibition of the phosphorylation of p38, JNK, ERK, iκB, and p65 proteins. Collectively, these data indicate that TCH has potential as a novel ingredient for the development of anti-photoaging foods.