Proteomic landscape subtype and clinical prognosis of patients with the cognitive impairment by Japanese encephalitis infection.

BACKGROUND: Cognitive impairment is one of the primary sequelae affecting the quality of life of patients with Japanese encephalitis (JE). The clinical treatment is mainly focused on life support, lacking of targeted treatment strategy. METHODS: A cerebrospinal fluid (CSF) proteomic profiling study was performed including 26 patients with JE in Gansu province of China from June 2017 to October 2018 and 33 other concurrent hospitalized patients who were excluded central nervous system (CNS) organic or CNS infection diseases. The clinical and proteomics data of patients with JE were undergoing combined analysis for the first time. RESULTS: Two subtypes of JE associated with significantly different prognoses were identified. Compared to JE1, the JE2 subtype is associated with lower overall survival rate and a higher risk of cognitive impairment. The percentages of neutrophils (N%), lymphocyte (L%), and monocytes (M%) decreased in JE2 significantly. CONCLUSIONS: The differences in proteomic landscape between JE subgroups have specificity for the prognosis of cognitive impairment. The data also provided some potential target proteins for treatment of cognitive impairments caused by JE. Trial registration ChiCTR, ChiCTR2000030499. Registered 1st June 2017, http://www.medresman.org.cn/pub/cn/proj/projectshow.aspx?proj=6333.

Construction and characterization of a novel fusion alginate lyase with endolytic and exolytic cleavage activity for industrial preparation of alginate oligosaccharides.

Alginate lyases with high activity and good thermostability are lacking for the preparation of alginate oligosaccharides (AOS) with various biological activities. We constructed a fusion alginate lyase with both endo-and exo-activities. AlyRm6A-Zu7 was successfully constructed by connecting the highly thermostable AlyRm6A to a new exotype lyase, AlyZu7. The fusion enzyme exhibited high catalytic activity and thermostability. It transformed sodium alginate into oligosaccharides with degrees of polymerization (DP) of 2-4 while producing 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH). The maximum reducing sugar, AOS, and DP1 + DEH yields were 75 %, 45 %, and 40 %, respectively. Molecular docking confirmed the formation of a stable complex between the substrate and AlyRm6A-Zu7. Protein interactions increased the thermostability of AlyZu7. This work provides new insights into the industrial formation of AOS and monosaccharide DEH using thermally stable fusion enzymes, which has a positive effect in the fields of functional oligosaccharide production and biofuel formation.

Recent advances in chromatography-mass spectrometry and electronic nose technology in food flavor analysis and detection.

Food flavor plays an important role in the consumption and acceptance of food, food production as well as food science research. Chromatography-mass spectrometry and electronic nose are the two most commonly used technologies in food flavor detection. Chromatography-mass has good qualitative and quantitative effect, wide detection range, and electronic nose is convenient and fast for practical application. In this paper, the principles, advantages and disadvantages, research progress and application in flavor fingerprinting of the two types of methods and their derived analytical techniques are reviewed. In particular, the application scenarios and advantages of different technologies combined are discussed in depth by summarizing studies that reflect the differences between different technologies. Finally, the current challenges and future directions of food flavor detection technology are discussed.

Current insights of factors interfering the stability of lytic polysaccharide monooxygenases.

Cellulose and chitin are two of the most abundant biopolymers in nature, but they cannot be effectively utilized in industry due to their recalcitrance. This limitation was overcome by the advent of lytic polysaccharide monooxygenases (LPMOs), which promote the disruption of biopolymers through oxidative mechanism and provide a breakthrough in the action of hydrolytic enzymes. In the application of LPMOs to biomass degradation, the key to consistent and effective functioning lies in their stability. The efficient transformation of biomass resources using LPMOs depends on factors that interfere with their stability. This review discussed three aspects that affect LPMO stability: general external factors, structural factors, and factors in the enzyme-substrate reaction. It explains how these factors impact LPMO stability, discusses the resulting effects, and finally presents relevant measures and considerations, including potential resolutions. The review also provides suggestions for the application of LPMOs in polysaccharide degradation.

Improving the thermostability of a novel PL-6 family alginate lyase by rational design engineering for industrial preparation of alginate oligosaccharides.

Alginate is degraded into alginate oligosaccharides with various biological activities by enzymes. However, the thermostability of the enzyme limits its industrial application. In this study, a novel PL-6 alginate lyase, AlyRm6A from Rhodothermus marinus 4252 was expressed and characterized. In addition, an efficient comprehensive strategy was proposed, including automatic design of heat-resistant mutants, multiple computer-aided ΔΔGfold value calculation, and conservative analysis of mutation sites. AlyRm6A has naturally high thermostability. Compared with the WT, T43I and Q216I kept their original activities, and their half-lives were increased from 3.68 h to 4.29 h and 4.54 h, melting point temperatures increased from 61.5 °C to 62.9 °C and 63.5 °C, respectively. The results of circular dichroism showed that both the mutants and the wild type had the characteristic peaks of ß-sheet at 195 nm and 216 nm, which indicated that there was no significant effect on the secondary structure of the protein. Molecular dynamics simulation (MD) analyses suggest that the enhancement of the hydrophobic interaction network, improvement of molecular rigidity, and denser structure could improve the stability of AlyRm6A. To the best of our knowledge, our findings indicate that AlyRm6A mutants exhibit the highest thermostability among the characterized PL-6 alginate lyases, making them potential candidates for industrial production of alginate oligosaccharides.

Controllable and complete conversion of agarose into oligosaccharides and monosaccharides by microwave-assisted hydrothermal and enzymatic hydrolysis and antibacterial activity of agaro-oligosaccharides.

Hydrolysis of agar or agarose can yield two types of oligosaccharides: agaro-oligosaccharides (AOS) and neoagaro-oligosaccharides (NAOS). These oligosaccharides have various biological activities and promising applications in the future food industry and pharmaceuticals. In this study, we prepared AOS from agarose by microwave-assisted hydrothermal hydrolysis and then used a commercial ß-galactosidase to treat AOS for producing NAOS. A complete conversion from agarose to AOS or NAOS can be achieved by microwave hydrothermal treatment and one-step enzyme reaction, and the production process was completely green. In addition, we combined ß-galactosidase and α-neoagarobiose hydrolase from Saccharophagus degradans 2-40 (SdNABH) to treat AOS, and AOS was completely converted into monosaccharides. Then the results of the inhibitory activity of AOS on the growth of Streptococcus mutans showed that AOS might be a good potential sugar substitute for dental caries prevention. This study provides an efficient approach for the production of multiple mixed degrees of polymerization (DP) of pure AOS and NAOS without requiring acid catalyst and agarases while simplifying the production processes and reducing costs.

Characterization of degradation patterns and enzymatic properties of a novel alkali-resistant alginate lyase AlyRm1 from Rubrivirga marina.

Alginate lyase is essential for the production of alginate oligosaccharides (AOSs), which exhibit diverse bioactivities and have numerous applications in the food and pharmaceutical industries. The creation of recombinant alginate lyase by genetic engineering lays a crucial foundation for the commercialization of alginate lyase. This study cloned and expressed the polysaccharide lyase family 6 (PL6) alginate lyase gene alyrm1 from Rubrivirga marina.The optimum temperature and pH for recombinant AlyRm1 are 30 °C and 10.0, respectively. AlyRm1 shows good alkaline stability, for it remained over 80% of the enzyme activity after being incubated at pH 10.0 for 24 h AlyRm1 preferentially degrades PolyM into AOSs with degrees of polymerization (DP) 2-5 and monosaccharides as an endolytic bifunctional lyase. In addition, the analysis of degradation products toward oligosaccharides revealed that the minimal substrate of AlyRm1 is trisaccharide and clarified the degradation patterns.

Machine learning reveals neutrophil-to-lymphocyte ratio as a crucial prognostic indicator in severe Japanese encephalitis patients.

Japanese encephalitis (JE) is a severe infectious disease affecting the central nervous system (CNS). However, limited risk factors have been identified for predicting poor prognosis (PP) in adults with severe JE. In this study, we analyzed clinical data from thirty-eight severe adult JE patients and compared them to thirty-three patients without organic CNS disease. Machine learning techniques employing branch-and-bound algorithms were used to identify clinical risk factors. Based on clinical outcomes, patients were categorized into two groups: the PP group (mRs ≥ 3) and the good prognosis (GP) group (mRs ≤ 2) at three months post-discharge. We found that the neutrophil-to-lymphocyte ratio (NLR) and the percentage of neutrophilic count (N%) were significantly higher in the PP group compared to the GP group. Conversely, the percentage of lymphocyte count (L%) was significantly lower in the PP group. Additionally, elevated levels of aspartate aminotransferase (AST) and blood glucose were observed in the PP group compared to the GP group. The clinical parameters most strongly correlated with prognosis, as indicated by Pearson correlation coefficient (PCC), were NLR (PCC 0.45) and blood glucose (PCC 0.45). In summary, our findings indicate that increased serum NLR, N%, decreased L%, abnormal glucose metabolism, and liver function impairment are risk factors associated with poor prognosis in severe adult JE patients.

Complete conversion of agarose into water soluble agaro-oligosaccharides by microwave assisted hydrothermal hydrolysis.

This study aims to produce oligosaccharides by microwave-assisted hydrothermal hydrolysis of agarose, which is a more environmentally friendly and green economical approach than acid or enzymatic hydrolysis. Under the optimized condition of 160 °C and 25 min, total liquefaction of agarose was achieved, the dominant products in the hydrolysate are agaro-oligosaccharides (AOs), with only a small portion of d-galactose and 5- hydroxymethylfurfural (5-HMF). This approach can produce even and odd number AOs simultaneously, which is due to the random hydrolysis of α-1,3 glycosidic linkage at first and subsequent hydrolysis of the ß-1,4 glycosidic linkage at the reducing end. The yield of AOs of a low degree of polymerization (DP) can reach about 57% of the theoretical maximum, while the total yield of AOs is over 90%. In conclusion, microwave-assisted hydrothermal hydrolysis is a way of producing oligosaccharides from agarose with extra-high efficiency and practical significance.

Recent advances in biotransformation, extraction and green production of D-mannose.

D-mannose is a natural and biologically active monosaccharide. It is the C-2 epimer of glucose and a component of a variety of polysaccharides in plants. In addition, D-mannose also naturally exists in some cells of the human body and participates in the immune regulation of cells as a prebiotic. Its good physiological benefits to human health and wide application in the food and pharmaceutical industries have attracted widespread attention. Therefore, in-depth research on preparation methods of D-mannose has been widely developed. This article summarizes the main production methods of D-mannose in recent years, especially the in-depth excavation from biomass raw materials such as coffee grounds, konjac flour, acai berry, etc., to provide new ideas for the green manufacture of D-mannose.