Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 98
Filter
1.
AMB Express ; 14(1): 8, 2024 Jan 20.
Article in English | MEDLINE | ID: mdl-38245573

ABSTRACT

The industrial applications of the κ-carrageenases have been restricted by their poor thermostability. In this study, based on the folding free energy change (ΔΔG) and the flexibility analysis using molecular dynamics (MD) simulation for the alkaline κ-carrageenase KCgCD from Pseudoalteromonas porphyrae (WT), the mutant S190R was identified with improved thermostability. After incubation at 50 °C for 30 min, the residual activity of S190R was 63.7%, 25.7% higher than that of WT. The Tm values determined by differential scanning calorimetry were 66.2 °C and 64.4 °C for S190R and WT, respectively. The optimal temperature of S190R was 10 °C higher than that of WT. The κ-carrageenan hydrolysates produced by S190R showed higher xanthine oxidase inhibitory activity compared with the untreated κ-carrageenan. MD simulation analysis of S190R showed that the residues (V186-M194 and P196-G197) in F5 and the key residue R150 in F3 displayed the decreased flexibility, and residues of T169-N173 near the catalytic center displayed the increased flexibility. These changed flexibilities might be the reasons for the improved thermostability of mutant S190R. This study provides a useful rational design strategy of combination of ΔΔG calculation and MD simulation to improve the κ-carrageenase's thermostability for its better industrial applications.

2.
Appl Microbiol Biotechnol ; 108(1): 15, 2024 Dec.
Article in English | MEDLINE | ID: mdl-38170310

ABSTRACT

Fungal infection has become a major threat to crop loss and affects food safety. The waste water from agar processing industries extraction has a number of active substances, which could be further transformed by microorganisms to synthesize antifungal active substances. In this study, Bacillus subtilis was used to ferment the waste water from agar processing industries extraction to analyze the antifungal activity of the fermentation broth on Alternaria alternata and Alternaria spp. Results showed that 25% of the fermentation broth was the most effective in inhibited A. alternata and Alternaria spp., with fungal inhibition rates of 99.9% and 96.1%, respectively, and a minimum inhibitory concentration (MIC) was 0.156 µg/mL. Metabolomic analysis showed that flavonoid polyphenols such as coniferyl aldehyde, glycycoumarin, glycitin, and procyanidin A1 may enhance the inhibitory activity against the two pathogenic fungal strains. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that polyphenols involved in the biosynthesis pathways of isoflavonoid and phenylpropanoid were upregulated after fermentation. The laser confocal microscopy analyses and cell conductivity showed that the cytoplasm of fungi treated with fermentation broth was destroyed. This study provides a research basis for the development of new natural antifungal agents and rational use of seaweed agar waste. KEY POINTS: • Bacillus subtilis fermented waste water has antifungal activity • Bacillus subtilis could transform active substances in waste water • Waste water is a potential raw material for producing antifungal agents.


Subject(s)
Antifungal Agents , Bacillus subtilis , Bacillus subtilis/metabolism , Antifungal Agents/pharmacology , Antifungal Agents/metabolism , Agar , Wastewater , Fermentation , Alternaria
3.
Food Funct ; 14(24): 10747-10758, 2023 Dec 11.
Article in English | MEDLINE | ID: mdl-37975749

ABSTRACT

Herein, we studied the in vitro-simulated intestinal flora fermentation of Porphyra haitanensis polysaccharides (PHPs) with microwave, ultrasonic, ultra-high pressure-assisted extraction and the protective effect of their fermented products against HT-29 human colon cancer cells. The results showed that PHPs were largely degraded at the 18 h stage of ascending colon fermentation, further greatly increasing the contents of reducing sugars and short-chain fatty acids (p < 0.05). Particularly, the PHPs subjected to ultra-high pressure-assisted extraction (UHP-PHP) showed the highest reducing sugar content of 1.68 ± 0.01 mg mL-1 and butyric acid content of 410.77 ± 7.99 mmol mL-1. Moreover, UHP-PHP showed a better effect in increasing the ratio of Bacteroidetes/Firmicutes and decreasing the abundance of Proteobacteria and Escherichia coli. PHPs could protect against HT-29 cells by increasing the ROS levels in a concentration-dependent manner, especially UHP-PHP fermented in a descending colon for 24 h. This was related to the up-regulated apoptosis-related genes (Bax and Bak), down-regulated protein expression of Bcl-2 and activation of the p-AKT protein, thereby promoting the apoptosis of HT-29 cells. Our results can facilitate the modification of PHPs and their practical application in the development of intestinal health improving products.


Subject(s)
Colonic Neoplasms , Gastrointestinal Microbiome , Porphyra , Humans , HT29 Cells , Fermentation , Polysaccharides/pharmacology , Polysaccharides/metabolism , Colonic Neoplasms/drug therapy , Butyric Acid
4.
World J Surg Oncol ; 21(1): 370, 2023 Nov 27.
Article in English | MEDLINE | ID: mdl-38008758

ABSTRACT

BACKGROUND: Gastroduodenal artery (GDA) stump erosion hemorrhage is a fatal complication after pancreaticoduodenectomy. This study aimed to determine whether GDA stump wrapping with the teres hepatis ligament during pancreaticoduodenectomy decreased the incidence of postpancreatectomy hemorrhage (PPH). METHODS: We reviewed 307 patients who had undergone pancreaticoduodenectomy between March 2019 and June 2022. The patients were divided into two groups according to application of GDA stump wrapping with the teres hepatis ligament: GDA wrapping group (165 patients) and no-wrapping group (142 patients). The perioperative data were compared between the groups. RESULTS: The clinical characteristics were balanced between the two groups. Grades B and C PPH and GDA-stump-related hemorrhage were significantly reduced in the GDA wrapping group compared with the no-wrapping group (PPH B/C, 13.4% vs 6.1%, P = 0.029; GDA hemorrhage, 5.6% vs 0.6%, P = 0.014). No difference was observed in the incidence of clinically relevant postoperative pancreatic fistula, biliary leak, intra-abdominal abscess, delayed gastric emptying, 90-day mortality, and postoperative hospital stay between the two groups. CONCLUSION: Wrapping GDA stump with the teres hepatis ligament reduced the incidence of GDA-stump-related PPH. Therefore, the wrapping technique is a simple and effective strategy to prevent PPH. Prospective studies are needed to confirm the benefit of this procedure.


Subject(s)
Pancreaticoduodenectomy , Postoperative Hemorrhage , Humans , Hepatic Artery/surgery , Ligaments/surgery , Pancreatic Fistula/etiology , Pancreaticoduodenectomy/adverse effects , Pancreaticoduodenectomy/methods , Postoperative Complications/etiology , Postoperative Complications/prevention & control , Postoperative Complications/surgery , Postoperative Hemorrhage/etiology , Postoperative Hemorrhage/prevention & control , Retrospective Studies
5.
J Nanobiotechnology ; 21(1): 324, 2023 Sep 08.
Article in English | MEDLINE | ID: mdl-37679769

ABSTRACT

BACKGROUND: Targeting EBV-proteins with mRNA vaccines is a promising way to treat EBV-related tumors like nasopharyngeal carcinoma (NPC). We assume that it may sensitize tumors to immune checkpoint inhibitors. RESULTS: We developed an LMP2-mRNA lipid nanoparticle (C2@mLMP2) that can be delivered to tumor-draining lymph nodes. C2@mLMP2 exhibited high transfection efficiency and lysosomal escape ability and induced an increased proportion of CD8 + central memory T cells and CD8 + effective memory T cells in the spleen of the mice model. A strong synergistic anti-tumor effect of C2@mLMP2 in combination with αPD-1 was observed in tumor-bearing mice. The mechanism was identified to be associated with a reverse of CD8 + T cell exhaustion in the tumor microenvironment. The pathological analysis further proved the safety of the vaccine and the combined therapy. CONCLUSIONS: This is the first study proving the synergistic effect of the EBV-mRNA vaccine and PD-1 inhibitors for EBV-related tumors. This study provides theoretical evidence for further clinical trials that may expand the application scenario and efficacy of immunotherapy in NPC.


Subject(s)
Herpesvirus 4, Human , Nasopharyngeal Neoplasms , Animals , Mice , Herpesvirus 4, Human/genetics , T-Cell Exhaustion , Immune Checkpoint Inhibitors/pharmacology , Nasopharyngeal Carcinoma/drug therapy , RNA, Messenger/genetics , Nasopharyngeal Neoplasms/drug therapy , Tumor Microenvironment
6.
Nanoscale ; 15(35): 14543-14550, 2023 Sep 14.
Article in English | MEDLINE | ID: mdl-37609952

ABSTRACT

Abnormal melanin overproduction can result in hyperpigmentation syndrome in human skin diseases and enzymatic browning of fruits and vegetables. Recently, our group found that Keggin-type polyoxometalates (POMs) can efficiently inhibit tyrosinase activity. However, it remains unclear whether Keggin-type POMs exhibit optimal effects in vivo. Additionally, the inhibitory effect and mechanism of action of POMs on cellular tyrosinase activity and melanogenesis have been rarely reported. Here we demonstrate that our screened and synthesised PMo11Zn and GaMo12 show superior inhibitory effects on melanin formation as well as inhibition of cellular tyrosinase activity compared to other Keggin-type POMs. Intriguingly, we reveal that Keggin-type POMs competitively bind to tyrosinase mainly through more interactions with Cu2+ ions and the amino acid residue is capable of forming van der Waals, cation-π and hydrogen bonds, resulting in a reversible non-covalent complex formation. Our findings provide valuable insights into the design, synthesis and screening of polyoxometalates as multifunctional metallodrugs and food preservatives against hyperpigmentation.


Subject(s)
Hyperpigmentation , Melanins , Humans , Monophenol Monooxygenase , Amino Acids
8.
Int J Biol Macromol ; 252: 126401, 2023 Dec 01.
Article in English | MEDLINE | ID: mdl-37597638

ABSTRACT

κ-Carrageenase can degrade κ-carrageenan to produce bioactive κ-carrageenan oligosaccharides (KCOs) that have potential applications in pharmaceutical, food, agricultural, and cosmetics industries. Immobilized enzymes gain their popularity due to their good reusability, enhanced stability, and tunability. In this study, the previously characterized catalytic domain of Pseudoalteromonas purpurea κ-carrageenase was covalently immobilized on the synthesized amine-modified zeolitic imidazolate framework-8 nanoparticles with the formation of cross-linked enzyme aggregates, and the immobilized κ-carrageenase was further characterized. The immobilized κ-carrageenase demonstrated excellent pH stability and good reusability, and exhibited higher optimal reaction temperature, better thermostability, and extended storage stability compared with the free enzyme. The KCOs produced by the immobilized κ-carrageenase could significantly decrease the TC, TG, and LDL-C levels in HepG2 cells, increase the HDL-C level in HepG2 cells, and reduce the free fatty acids level in Caco-2 cells. Biochemical assays showed that the KCOs could activate AMPK activity, increase the ratios of p-AMPK/AMPK and p-ACC/ACC, and downregulate the expression of the lipid metabolism related proteins including SREBP1 and HMGCR in the hyperlipidemic HepG2 cells. This study provides a novel and effective method for immobilization of κ-carrageenase, and the KCOs produced by the immobilized enzyme could be a potential therapeutic agent to prevent hyperlipidemia.


Subject(s)
AMP-Activated Protein Kinases , Bacterial Proteins , Humans , Carrageenan/chemistry , Caco-2 Cells , Hep G2 Cells , Bacterial Proteins/chemistry , Glycoside Hydrolases/chemistry , Oligosaccharides/chemistry , Enzymes, Immobilized
9.
J Ind Microbiol Biotechnol ; 50(1)2023 Feb 17.
Article in English | MEDLINE | ID: mdl-37580133

ABSTRACT

Astaxanthin has high utilization value in functional food because of its strong antioxidant capacity. However, the astaxanthin content of Phaffia rhodozyma is relatively low. Adaptive laboratory evolution is an excellent method to obtain high-yield strains. TiO2 is a good inducer of oxidative stress. In this study, different concentrations of TiO2 were used to domesticate P. rhodozyma, and at a concentration of 1000 mg/L of TiO2 for 105 days, the optimal strain JMU-ALE105 for astaxanthin production was obtained. After fermentation, the astaxanthin content reached 6.50 mg/g, which was 41.61% higher than that of the original strain. The ALE105 strain was fermented by batch and fed-batch, and the astaxanthin content reached 6.81 mg/g. Transcriptomics analysis showed that the astaxanthin synthesis pathway, and fatty acid, pyruvate, and nitrogen metabolism pathway of the ALE105 strain were significantly upregulated. Based on the nitrogen metabolism pathway, the nitrogen source was adjusted by ammonium sulphate fed-batch fermentation, which increased the astaxanthin content, reaching 8.36 mg/g. This study provides a technical basis and theoretical research for promoting industrialization of astaxanthin production of P. rhodozyma. ONE-SENTENCE SUMMARY: A high-yield astaxanthin strain (ALE105) was obtained through TiO2 domestication, and its metabolic mechanism was analysed by transcriptomics, which combined with nitrogen source regulation to further improve astaxanthin yield.


Subject(s)
Xanthophylls , Directed Molecular Evolution , Gene Expression Profiling , Basidiomycota/chemistry , Basidiomycota/classification , Basidiomycota/genetics , Basidiomycota/growth & development , Biomass , Glucose/analysis , Carotenoids/analysis , Fermentation , Batch Cell Culture Techniques , Nitrogen/metabolism , Xanthophylls/chemistry , Xanthophylls/metabolism
10.
Front Oncol ; 13: 1214451, 2023.
Article in English | MEDLINE | ID: mdl-37427118

ABSTRACT

Background: Ex vivo liver resection and autotransplantation (ELRAT) may provide an opportunity for R0 resection of conventionally unresectable hepatobiliary cancers and hepatic metastases. To date, few studies of the surgery for malignant tumors have been conducted and there are no known reports of in vivo partial hepatectomy followed by ELRAT (IPH-ELRAT) for malignant tumors. Methods: Between December 2021 and November 2022, ten patients with malignant hepatobiliary primary cancers or hepatic metastases underwent ELRAT at our institution. We shared the surgical skills and postoperative prognoses of these patients were assessed. Results: The types of tumors were biliary tract cancer (BTC, n=8), hepatic metastasis of colonic carcinoma (n=1), and hepatic metastasis of small-bowel stromal tumor (n=1). Five patients underwent in vivo total hepatectomy followed by ex vivo liver resection and autotransplantation (ITH-ELRAT), The other five received in vivo partial hepatectomy followed by ex vivo liver resection and autotransplantation (IPH-ELRAT). Four patients underwent inferior vena cava replacement using artificial blood vessels. The survival rate of all ten patients one month after surgery was 100%. Nine patients (90%) are currently alive, with a median follow-up of 8.5 months (range 6-16.5 months). To date, seven of the nine surviving patients have had no cancer recurrence, including six with BTC. Conclusions: We report the world first five cases that received IPH-ELRAT for malignancies. We also demonstrated relatively favorable outcomes in patients who underwent ELRAT. ELRAT may be a recommendable surgical option for selected patients with conventionally unresectable hepatobiliary malignant tumors.

11.
J Nanobiotechnology ; 21(1): 212, 2023 Jul 07.
Article in English | MEDLINE | ID: mdl-37415161

ABSTRACT

Although cancer immunotherapy is a compelling approach against cancer, its effectiveness is hindered by the challenge of generating a robust and durable immune response against metastatic cancer cells. Nanovaccines, specifically engineered to transport cancer antigens and immune-stimulating agents to the lymph nodes, hold promise in overcoming these limitations and eliciting a potent and sustained immune response against metastatic cancer cells. This manuscript provides an in-depth exploration of the lymphatic system's background, emphasizing its role in immune surveillance and tumor metastasis. Furthermore, it delves into the design principles of nanovaccines and their unique capability to target lymph node metastasis. The primary objective of this review is to provide a comprehensive overview of the current advancements in nanovaccine design for targeting lymph node metastasis, while also discussing their potential to enhance cancer immunotherapy. By summarizing the state-of-the-art in nanovaccine development, this review aims to shed light on the promising prospects of harnessing nanotechnology to potentiate cancer immunotherapy and ultimately improve patient outcomes.


Subject(s)
Lymph Nodes , Neoplasms , Cancer Vaccines , Immunotherapy/methods , Neoplasms/immunology , Neoplasms/therapy , Nanotechnology , Drug Delivery Systems , Humans , Animals , Combined Modality Therapy
12.
Yeast ; 40(7): 254-264, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37132227

ABSTRACT

Astaxanthin is a valuable carotenoid and is used as antioxidant and health care. Phaffia rhodozyma is a potential strain for the biosynthesis of astaxanthin. The unclear metabolic characteristics of P. rhodozyma at different metabolic stages hinder astaxanthin's promotion. This study is conducted to investigate metabolite changes based on quadrupole time-of-flight mass spectrometry metabolomics method. The results showed that the downregulation of purine, pyrimidine, amino acid synthesis, and glycolytic pathways contributed to astaxanthin biosynthesis. Meanwhile, the upregulation of lipid metabolites contributed to astaxanthin accumulation. Therefore, the regulation strategies were proposed based on this. The addition of sodium orthovanadate inhibited the amino acid pathway to increase astaxanthin concentration by 19.2%. And the addition of melatonin promoted lipid metabolism to increase the astaxanthin concentration by 30.3%. It further confirmed that inhibition of amino acid metabolism and promotion of lipid metabolism were beneficial for astaxanthin biosynthesis of P. rhodozyma. It is helpful in understanding metabolic pathways affecting astaxanthin of P. rhodozyma and provides regulatory strategies for metabolism.


Subject(s)
Basidiomycota , Carotenoids , Xanthophylls/metabolism , Basidiomycota/chemistry , Metabolomics
13.
Environ Sci Pollut Res Int ; 30(26): 69349-69361, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37133661

ABSTRACT

There is a growing global demand for clean energy, driven by concerns over global warming and the need to decrease greenhouse gas emissions. This research uses a nonparametric approach to analyze the correlation between industrialization and the use of clean energy sources in 16 countries between 1995 and 2020. We utilize a technique called the local linear dummy variable estimate to monitor the effects of globalization on the development of sustainable power over time. An unfavorable and economically important link was found between industrialization and the use of sustainable energy supplies from 2003 to 2012, as determined by an examination of nonparametric econometric techniques. Still, it started moving in the opposite direction, becoming significant and positive after 2014. In addition, we discover that globalization has various effects on the various indices of the use of renewable energy sources. The research also reveals that the effects of globalization on RES vary across different regions, with some regions experiencing more significant benefits than others. Overall, the study provides valuable insights into the complex relationship between globalization and RES and highlights the need for further research to inform policy decisions and promote sustainable development.


Subject(s)
Energy-Generating Resources , Greenhouse Gases , Global Warming , Renewable Energy , Internationality , Carbon Dioxide , Economic Development
14.
Int J Biol Macromol ; 242(Pt 2): 125003, 2023 Jul 01.
Article in English | MEDLINE | ID: mdl-37217048

ABSTRACT

This study was to investigate the structure and antioxidant activity of Porphyra haitanensis polysaccharides (PHPs) extracted by different methods, including water extraction (PHP), ultra-high pressure (UHP-PHP), ultrasonic (US-PHP) and microwave assisted water extraction (M-PHP). Compared with water extraction, the total sugar, sulfate and uronic acid contents of PHPs was enhanced by ultra-high pressure, ultrasonic and microwave assisted treatments, especially those of UHP-PHP were increased by 24.35 %, 12.84 % and 27.51 %, respectively (p < 0.05). Meanwhile, these assisted treatments affected the monosaccharide ratio of polysaccharides and significantly reduced the protein content, molecular weight as well as particle size of PHPs (p < 0.05), and resulted in a loose microstructure with more porosity and fragments. PHP, UHP-PHP, US-PHP, and M-PHP all possessed in vitro antioxidant capacity. Among them, UHP-PHP had the strongest oxygen radical absorbance capacity, DPPH and ·OH radicals scavenging capacities, which increased by 48.46 %, 116.24 %, and 14.98 % respectively. Moreover, PHPs particularly UHP-PHP effectively increased the cell viability and reduced ROS levels of H2O2 induced RAW264.7 cells (p < 0.05), indicating their good effects against cell oxidative damage. The findings suggested that PHPs with ultra-high pressure assisted treatments has the better potential to develop natural antioxidant.


Subject(s)
Antioxidants , Porphyra , Antioxidants/chemistry , Porphyra/chemistry , Hydrogen Peroxide/metabolism , Polysaccharides/chemistry , Water/metabolism
15.
Enzyme Microb Technol ; 167: 110241, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37060759

ABSTRACT

κ-Carrageenase provides an attractive enzymatic approach to preparation of κ-carrageenan oligosaccharides. Pseudoalteromonas tetraodonis κ-carrageenase is active at the alkaline conditions but displays low thermostability. To further improve its enzymatic performance, two mutants of Q42V and I51H exhibiting both improved thermostability and enzyme activity were screened by the PoPMuSiC algorithm. Compared with the wild-type κ-carrageenase (WT), Q42V and I51H increased the enzyme activity by 20.9% and 25.4%, respectively. After treatment at 50 â„ƒ for 40 min, Q42V and I51H enhanced the residual activity by 31.1% and 25.9%, respectively. The Tm values of Q42V, I51H, and WT determined by differential scanning calorimetry were 58.2 â„ƒ, 54.8 â„ƒ, and 51.2 â„ƒ, respectively. Compared with untreated and HCl-treated κ-carrageenans, Q42V-treated κ-carrageenan exhibited higher pancreatic lipase inhibitory activity. Molecular docking analysis indicated that the additional pi-sigma force and hydrophobic interaction in the enzyme-substrate complex could account for the increased catalytic activity of Q42V and I51H, respectively. Molecular dynamics analysis indicated that the improved thermostability of mutants Q42V and I51H could be attributed to the less structural deviation and the flexible changes of enzyme conformation at high temperature. This study provides new insight into κ-carrageenase performance improvement and identifies good candidates for their industrial applications.


Subject(s)
Glycoside Hydrolases , Pseudoalteromonas , Carrageenan/chemistry , Molecular Docking Simulation , Glycoside Hydrolases/genetics , Glycoside Hydrolases/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/chemistry , Pseudoalteromonas/genetics
16.
Front Oncol ; 13: 1138068, 2023.
Article in English | MEDLINE | ID: mdl-36890822

ABSTRACT

Background: Recently, in many Asian centers, laparoscopic anatomical liver resection (LALR) using the indocyanine green (ICG) fluorescence imaging technique has been increasingly applied in resecting hepatocellular carcinoma, even in colorectal liver metastases. However, LALR techniques have not been fully standardized, especially in right superior segments. Due to the anatomical position, prevailing positive staining using a PTCD (percutaneous transhepatic cholangial drainage) needle was superior to negative staining in right superior segments hepatectomy, while it was difficult to manipulate. Herein, we design a novel method of ICG-positive staining for LALR of right superior segments. Methods: Between April 2021 and October 2022, we retrospectively studied patients in our institute who underwent LALR of right superior segments using a novel method of ICG-positive staining, which comprised a customized puncture needle and an adaptor. Compared to the PTCD needle, the customized needle was not limited by the abdominal wall and could be punctured from the liver dorsal surface, which was more flexible to manipulate. The adapter was attached to the guide hole of the laparoscopic ultrasound (LUS) probe to ensure the precise puncture path of the needle. Guided by preoperative three-dimensional (3D) simulation and intraoperative laparoscopic ultrasound imaging, we punctured the transhepatic needle into the target portal vein through the adaptor and then slowly injected 5-10 ml of 0.025 mg/ml ICG solution into the vessel. LALR can be guided by the demarcation line under fluorescence imaging after injection. Demographic, procedural and postoperative data were collected and analyzed. Results: In this study, 21 patients underwent LALR of the right superior segments with ICG fluorescence-positive staining, and the procedures had a success rate of 71.4%. The average staining time was 13.0 ± 6.4 min, the operative time was 230.4 ± 71.7 min, R0 resection was 100%, the postoperative hospital stay was 7.1 ± 2.4 days, and no severe puncture complications occurred. Conclusions: The novel customized puncture needle approach seems to be feasible and safe for ICG-positive staining in LALR of right superior segments, with a high success rate and a short staining time.

17.
Gels ; 9(3)2023 Mar 11.
Article in English | MEDLINE | ID: mdl-36975664

ABSTRACT

The effect of black tea powder on the antioxidant activity and gel characteristics of fish balls from silver carp were investigated after freezing storage for 7 days. The results show that black tea powder with different concentrations of 0.1%, 0.2% and 0.3% (w/w) could significantly increase the antioxidant activity of fish balls (p < 0.05). In particular, at the concentration of 0.3%, the antioxidant activity was the strongest among these samples, where the reducing power, DPPH, ABTS and OH free radical scavenging rate were up to 0.33, 57.93%, 89.24% and 50.64%, respectively. In addition, black tea powder at the level of 0.3% significantly increased the gel strength, hardness and chewiness while greatly reducing the whiteness of the fish balls (p < 0.05). ESEM observation found that the addition of black tea powder could promote the crosslinking of proteins and reduced the pore size of the gel network structure of the fish balls. The results suggest that black tea powder could be used as a natural antioxidant and gel texture enhancer in fish balls, which we found to be much related to the phenolic compounds of black tea powder.

18.
Food Funct ; 14(2): 1133-1147, 2023 Jan 23.
Article in English | MEDLINE | ID: mdl-36594623

ABSTRACT

A combination of polysaccharides and tea polyphenols can enhance immune activity synergistically, depending on the type and structure of polysaccharides, but the mechanism remains unknown. This study is aimed to investigate the regulating effects of different seaweed polysaccharide (ι-carrageenan, agarose) and tea polyphenol blends on intestinal flora and intestinal inflammation using an in vitro ascending-transverse-descending colon fermentation system and RAW264.7 cell model. The results showed that seaweed polysaccharides in the presence of tea polyphenol were almost completely degraded at transverse colon fermentation for 36 h. Agarose significantly enhanced the butyric acid production content by increasing the abundance of Lachnospiraceae, whereas agarose and tea polyphenol blends did not have a synergistic effect. On the contrary, ι-carrageenan and tea polyphenol blends synergistically increased the abundance of beneficial bacteria (e.g., Bacteroidetes and Bifidobacterium) and promoted the production of short-chain fatty acids (SCFAs), such as isobutyric acid. Such changes tended to alter the impacts of different seaweed polysaccharides and tea polyphenol blends on intestinal inflammation. Among them, ι-carrageenan and tea polyphenol blends were the most effective in inhibiting lipopolysaccharide-induced NO, ROS, IL-6, and TNF-α production in RAW264.7 cells, indicating the alleviated intestinal inflammation. The results suggest that the seaweed polysaccharide and tea polyphenol blends have prebiotic potential and can benefit intestinal health.


Subject(s)
Gastrointestinal Microbiome , Seaweed , Humans , Seaweed/metabolism , Fermentation , Carrageenan , Sepharose , Polyphenols/pharmacology , Polysaccharides/pharmacology , Tea/chemistry , Inflammation
19.
AMB Express ; 12(1): 139, 2022 Nov 05.
Article in English | MEDLINE | ID: mdl-36335230

ABSTRACT

Marine bacterium Microbulbifer sp. ALW1 was revealed to be able to effectively degrade Laminaria japonica thallus fragments into fine particles. Polysaccharide substrate specificity analysis indicated that ALW1 could produce extracellular alginate lyase, laminarinase, fucoidanase and cellulase. Based on alignment of the 16 S rRNA sequence with other reference relatives, ALW1 showed the closest relationship with Microbulbifer aggregans CCB-MM1T. The cell morphology and some basic physiological and biochemical parameters of ALW1 cells were characterised. ALW1 is a Gram-negative, rod- or oval-shaped, non-spore-forming and non-motile bacterium. The DNA-DNA relatedness values of ALW1 with type strains of M. gwangyangensis (JCM 17,800), M. aggregans (JCM 31,875), M. maritimus (JCM 12,187), M. okinawensis (JCM 16,147) and M. rhizosphaerae (DSM 28,920) were 28.9%, 43.3%, 41.2%, 35.4% and 45.6%, respectively. The major cell wall sugars of ALW1 were determined to be ribose and galactose, which differed from other closely related species. These characteristics indicated that ALW1 could be assigned to a separate species of the genus Microbulbifer. The complete genome of ALW1 contained one circular chromosome with 4,682,287 bp and a GC content of 56.86%. The putative encoded proteins were categorised based on their functional annotations. Phenotypic, physiological, biochemical and genomic characterisation will provide insights into the many potential industrial applications of Microbulbifer sp. ALW1.Key points.

SELECTION OF CITATIONS
SEARCH DETAIL
...