Formation of fluorescent carbon nanodots from kitchen wastes and their application for detection of Fe(3.).

This work reports a scalable synthesis of water-dispersible fluorescent carbon nanodots based on the simple hydrothermal method (180 °C for 6 h) of kitchen wastes (grape peel for example). We discuss the feasibility of synthesis from kitchen wastes both experimentally and theoretically, and the as-prepared nanodots have high selectivity for Fe(3+) ions based on fluorescence quenching which is due to the complexes between nanodots and metal ions.

Biosynthesis of lactosucrose by a new source of ß-fructofuranosidase from Bacillus methanolicus LB-1.

Lactosucrose (LS) is a prebiotic trisaccharide enzymatically synthesized by transglycosylation from lactose and sucrose with beneficial health effect. The ß-fructofuranosidase used for synthesis of LS was produced from Bacillus methanolicus LB-1, which was isolated from traditional rice wine. A maximal yield of 8.63 U/mL of the enzyme was obtained by fermentation with B. methanolicus LB-1 under the optimized conditions: 10 g/L of glucose, 5 g/L of yeast extract, initial medium pH at 7.0, 37 °C, 24 h. The enzyme was purified and identified by ammonium sulfate fractional precipitation, Sephadex G-75 gel filtration chromatography and LC-MS, and SDS-PAGE of the purified enzyme showed a major protein band at 45 kDa. Biosynthesis of LS was performed using the purified ß-fructofuranosidase, and production of LS reached 110 g/L under the optimized reaction conditions: pH at 7.0, 37 °C, 6.0 U/g sucrose of enzyme, 15% of sucrose, 15% of lactose, 28 h. HPLC analysis of the reaction products showed a distinct peak for LS at about 30 min of elution, confirming that B. methanolicus LB-1 ß-fructofuranosidase had effective transfructosylation activity. Therefore, this new microbial source of ß-fructofuranosidase may be a candidate with potential application prospect in biosynthesis of prebiotic LS.

The DEAD-box RNA helicase, DDX60, Suppresses immunotherapy and promotes malignant progression of pancreatic cancer.

Excessive proliferation, invasion, metastasis, and immune resistance in pancreatic cancer (PC) makes it one of the most lethal malignant tumors. Recently, DDX60 was found to be involved in the development of various tumors and in immunotherapy. Therefore, we aimed to investigate whether DDX60 is a new factor involved in PC immunotherapy. The DDX60 mRNA was screened using transcriptome sequencing (RNA-seq). The Cox and survival analysis of DDX60 was performed using the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. In addition, clinical and immune infiltration data in the databases were analyzed and plotted using the R language. Clinical samples and in vitro experiments were used to determine the molecular evolution of DDX60 during PC progression. We found that DDX60 was upregulated in PC tissues (P value = 0.0083) and was associated with poor prognosis and short survival time of patients with PC. Results of Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and gene set variation analyses showed that viral defense, tumor, and immune-related pathways were significantly enriched in samples with high DDX60 expression. The Pearson correlation test demonstrated that DDX60 expression correlated strongly with immune checkpoint and immune system-related metagene clusters. Our results indicated that DDX60 promoted cell proliferation, migration, and invasion and was related to poor prognosis and immune resistance. Therefore, DDX60 may be a promising novel target for PC immunotherapy.

miR-33a-3p regulates METTL3-mediated AREG stability and alters EMT to inhibit pancreatic cancer invasion and metastasis.

Recent studies have shown that amphoteric regulatory protein (AREG), a member of the epidermal growth factor (EGF) family, is expressed in many cancers and is an independent prognostic indicator for patients with pancreatic cancer, but whether AREG is regulated at the epigenetic level to promote the development of pancreatic cancer (PC) has not been elucidated. Our results support the notion that AREG is overexpressed in pancreatic cancer tissues and cell lines. Functionally, the deletion of AREG impedes pancreatic cancer (PC) cell proliferation, migration, and invasion. In addition, we identified and validated that methyltransferase-like 3 (METTL3) induced the m6A modification on AREG and facilitated the stability of AREG mRNA after sequencing. Additionally, we obtained experimental evidence that miR-33a-3p targets and inhibits METTL3 from taking action, as predicted by using the miRDB and RNAinter. Remediation experiments showed that miR-33a-3p inhibits PC progression through METTL3. In summary, this research reveals that miR-33a-3p inhibits m6A-induced stabilization of AREG by targeting METTL3, which plays a key role in the aggressive progression of PC. AREG could be a potential target for PC treatment.

Linc00662 m6A promotes the progression and metastasis of pancreatic cancer by activating focal adhesion through the GTF2B-ITGA1-FAK pathway.

Recurrence and metastasis are major factors associated with the poor prognosis of pancreatic cancer (PC). Previous studies have indicated that METTL3-mediated N6-methyladenosine (m6A) modification is closely associated with PC progression and prognosis. However, its underlying regulatory mechanisms remain unclear. In this study, we found that METTL3 was upregulated in PC tissues and cells and was associated with malignant tumor progression and poor progression-free survival in PC. Linc00662 was screened as a m6A-enriched RNA that promoted tumor growth and metastasis in PC cells and mouse models and was associated with poor clinical prognosis. Four m6A motifs were identified in Linc00662, which maintained the stability of Linc00662 in an IGF2BP3-coupled manner and were closely associated with the pro-tumor properties of Linc00662 in vitro and in vivo. ITGA1 was identified as a downstream gene regulated by Linc00662. Linc00662 recruites GTF2B to activate the transcription of ITGA1 in a m6A-dependent manner and initiates the formation of focal adhesions through the ITGA1-FAK-Erk pathway, thereby promoting malignant behavior in PC cells. The FAK inhibitor-Y15 obviously repressed tumor progression in Linc00662-overexpressing PC cells in vitro and in vivo. This study proposes a novel regulatory mechanism of Linc00662 in oncogene activation in PC and indicates that Linc00662 and its downstream genes are potential targets for PC therapy.

Characterization and In Vitro Fecal Microbiota Regulatory Activity of a Low-Molecular-Weight Exopolysaccharide Produced by Lactiplantibacillus plantarum NMGL2.

The exopolysaccharide (EPS) produced by Lactiplantibacillus plantarum NMGL2 isolated from traditional fermented dairy cheese was purified chromatographically with DEAE-Sepharose and Sepharose CL-6B columns. The purified EPS was characterized by various physicochemical methods and in vitro fecal microbiota regulation assay. The results showed that the EPS had a relatively low molecular weight of 3.03 × 104 Da, and it had a relatively high degradation temperature of 245 °C as determined by differential scanning calorimetry. Observation of the EPS by scanning electron microscopy, transmission electron microscopy, and atomic force microscopy revealed a highly branched and tangled fibrous network microstructure with many hollow microtubules and spherical particles. Structural study by 1H NMR spectroscopy suggested that the EPS contained a tetrasaccharide repeating unit with monosaccharide components of ß-galactose (4.6%), α-glucose (20.6%), and α-mannose (74.8%). The EPS was highly resistant to hydrolysis of simulated human saliva, gastric, and intestinal juices. Moreover, the EPS beneficially affected the composition and diversity of the fecal microbiota, e.g., increasing the relative abundance of Firmicutes and inhibiting that of Proteobacteria. The results of this study indicated significant bioactivity of this novel low-molecular-weight EPS produced by Lpb. plantarum NMGL2, which could serve as a bioactive agent for potential applications in the food and health care industry.

Interaction of the Exopolysaccharide from Lactobacillus plantarum YW11 with Casein and Bioactivities of the Polymer Complex.

There has been an increased application of exopolysaccharide (EPS)-producing lactic acid bacteria (LAB) in fermented dairy products, but interactions between EPS and casein (CAS), and bioactivities of their complex are poorly studied. In this study, EPS produced by Lactobacillus plantarum YW11 (EPS-YW11) was studied for interactions with CAS in a simulated fermentation system acidified by D-(+)-gluconic acid δ-lactone. The results showed that there was interaction between EPS-YW11 and CAS when EPS (up to 1%, w/v) was added to the casein solution (3%, w/v) as observed with increased viscoelasticity, water holding capacity, ζ-potential and particle size of EPS-YW11/CAS complex compared with CAS alone. Microstructural analysis showed that a higher concentration of EPS facilitated more even distribution of CAS particles that were connected through the polysaccharide chains. Infrared spectroscopy further confirmed interactions between EPS and CAS by intermolecular hydrogen bonding, electrostatic and hydrophobic contacts. Further evaluation of the bioactivities of EPS-YW11/CAS complex revealed significantly increased antibiofilm, antioxidation, and bile acids binding capacity. The present study provides further understanding on the mechanism of interactions between EPS produced by LAB and CAS, which would benefit potential applications of EPS in fermented dairy products with enhanced functionality.

Response of Lactiplantibacillus plantarum NMGL2 to Combinational Cold and Acid Stresses during Storage of Fermented Milk as Analyzed by Data-Independent Acquisition Proteomics.

To understand the mechanism of tolerance of lactic acid bacteria (LAB) during cold storage of fermented milk, 31 LAB strains were isolated from traditional fermented products, and Lactiplantibacillus plantarum NMGL2 was identified with good tolerance to both cold and acid stresses. Data-independent acquisition proteomics method was employed to analyze the response of Lpb. plantarum NMGL2 to the combinational cold and acid stresses during storage of the fermented milk made with the strain at 4 °C for 21 days. Among the differentially expressed proteins identified, 20 low temperature-resistant proteins and 10 acid-resistant proteins were found. Protein interaction analysis showed that the low temperature-resistant proteins associated with acid-resistant proteins were Hsp1, Hsp2, Hsp3, CspC, MurA1, MurC, MurD, MurE1, and MurI, while the acid-resistant proteins associated with low temperature-resistant proteins were DnaA, DnaK, GrpE, GroEL, and RbfA. The overall metabolic pathways of Lpb. plantarum NMGL2 in response to the stresses were determined including increased cell wall component biosynthesis, extracellular production of abundant glycolipids and glycoproteins, increased expression of F1Fo-ATPase, activation of glutamate deacidification system, enhanced expression of proteins and chaperones associated with cell repairing caused by the acidic and cold environment into the correct proteins. The present study for the first time provides further understanding of the proteomic pattern and metabolic changes of Lpb. plantarum in response to combinational cold and acid stresses in fermented milk, which facilitates potential application of Lpb. plantarum in fermented foods with enhanced survivability.

Hybrid carbon source for producing nitrogen-doped polymer nanodots: one-pot hydrothermal synthesis, fluorescence enhancement and highly selective detection of Fe(III).

Polymer nanodots (PNDs) from a hybrid carbon source (glucose and glycine) which exhibit a stronger fluorescence than the PNDs from a single source (glucose or glycine) are obtained by one-pot hydrothermal treatment. It is attractive that PNDs can be used as an effective fluorescent probe for the detection of iron ions with good selectivity and sensitivity in an aqueous solution.