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The aim of this paper was to explore the process of β-glucosidase-assisted extraction of flavonoids from thinned fruits of Guanxi pummelo and the inhibitory effect of the extracted flavonoids on tyrosinase. In this paper, the extraction amount of total flavonoids was used as the index, and the β-glucosidase activity, enzymatic hydrolysis pH, temperature and time were optimized by single factor and response surface experiments, and the inhibitory effect of total flavonoids extract on tyrosinase was studied. The results showed that the optimal conditions for the extraction of flavonoids from thinned fruits of Guanxi pummelo were as follows: β-Glucosidase enzyme activity 0.0128 U/mL, enzymolysis pH4.4, temperature 35 ℃, time 4.8 h. Under these conditions, the extraction amount of total flavonoids was 34.0 mg/g, the half maximal inhibitory concentration (IC50) of the flavonoids extract on tyrosinase was 0.31 mg/mL. The results of this study showed that the enzymatic process could significantly improve the extraction amount of flavonoids from thinned fruits of Guanxi pummelo, and the flavonoids from thinned fruits of Guanxi pummelo had strong tyrosinase inhibition. The results of this study provided a reference for the extraction and application of flavonoids from thinned fruits of Guanxi pummelo, which was conducive to promoting the high-value utilization of Guanxi pummelo.

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 T m 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.

Tea products, such as instant tea, have been shown to improve the aroma of meat products. However, the mechanisms by which tea products enhance meat aroma have not been adequately explained. In this study, we analyzed the impact of instant tea on the aroma of duck meat. Our results showed that treatment with instant tea led to increases in floral, baked, and grassy notes while reducing fishy and fatty notes. Several alcohols, aldehydes, ketones, indole and dihydroactinidiolide exhibited significantly increased OAVs. Conversely, certain saturated aldehydes, unsaturated aldehydes and alcohols displayed significantly decreased OAVs. The enhanced floral, baked and grassy notes were attributed to volatile compounds present in instant tea. The reduction in fishy and fatty notes was linked to polyphenols in instant tea interacting with nonanal, undecanal, (E)-2-octenal, (E)-2-nonenal, (E)-2-decenal, and 2,4-decadienal through hydrophobic interactions and electronic effects. This study enhances our understanding of how tea products improve meat aromas.

Sepsis-induced myocardial dysfunction (SIMD) is associated with poor prognosis and increased mortality in patients with sepsis. Cytokines are important regulators of both the initiation and progression of sepsis. Interleukin-15 (IL-15), a pro-inflammatory cytokine, has been linked to protective effects against myocardial infarction and myocarditis. However, the role of IL-15 in SIMD remains unclear. We established a mouse model of SIMD via cecal ligation puncture (CLP) surgery and a cell model of myocardial injury via lipopolysaccharide (LPS) stimulation. IL-15 expression was prominently upregulated in septic hearts as well as cardiomyocytes challenged with LPS. IL-15 pretreatment attenuated cardiac inflammation and cell apoptosis and improved cardiac function in the CLP model. Similar cardioprotective effects of IL-15 pretreatment were observed in vitro. As expected, IL-15 knockdown had the opposite effect on LPS-stimulated cardiomyocytes. Mechanistically, we found that IL-15 pretreatment reduced the expression of the pro-apoptotic proteins cleaved caspase-3 and Bax and upregulated the anti-apoptotic protein Bcl-2. RNA sequencing and Western blotting further confirmed that IL-15 pretreatment suppressed the activation of nuclear factor kappa B (NF-κB) signaling in mice with sepsis. Besides, the addition of NF-κB inhibitor can significantly attenuate cardiomyocyte apoptosis compared to the control findings. Our results suggest that IL-15 pretreatment attenuated the cardiac inflammatory responses and reduced cardiomyocyte apoptosis by partially inhibiting NF-κB signaling in vivo and in vitro, thereby improving cardiac function in mice with sepsis. These findings highlight a promising therapeutic strategy for SIMD.

In order to improve the quality of wheat noodles, the compounding gels were prepared by enzymatic hydrolysis of konjac gum and carrageenan to study its effects on quality of wheat noodle. The additions of compounding gels, salt and water were selected as single factors, and cooking, texture, and sensory properties were used as evaluation indexes to optimize the processing condition of wheat noodles by response surface and principal component analysis. The optimum formula determined as follows: based on 150 g of wheat flour as 100%, the compounding gel was 3%, salt was 1% and water was 43%. Under these conditions, the improved noodles had the best comprehensive quality, with a cooking yield of 64% and a cooking loss of 4.5%. Compared with the traditional wheat noodles, the cooking yield, hardness and chewiness of the improved noodles were increased by 3.8%, 18.6% and 2.1%, respectively, whereas the cooking loss and stickiness values decreased by 7.3% and 2.9%, respectively. The comprehensive quality of noodles was improved with sensory score increasing from 69.9 to 82.9. This study showed that enzymatic konjac gum and carrageenan compound gelling agent could be used as a noodle improver to enhance the quality of wheat noodles, and the results of the study provided a certain reference for the development of konjac gum and carrageenan compound gelling agent and its application research.

It is important to eliminate the fishy odor and improve the aroma quality of seafood. In this study, the Saccharina japonica (S. japonica) seedling, which is a new food material, was investigated for the effects of fermentation with Saccharomyces cerevisiae (S. cerevisiae) through sensory evaluation, GC–MS, and odor activity value (OAV) analysis. GC–MS analysis revealed the presence of 43 volatile compounds in the unfermented S. japonica seedling, with 1-octen-3-ol, hexanal, and trans-2,4-decadienal identified as the main contributors to its fishy odor. After fermentation with S. cerevisiae, 26 volatile compounds were identified in the S. japonica seedling. Notably, the major malodorous fish compounds, including 1-octen-3-ol, hexanal and trans-2,4-decadienal, were no longer present. The results indicate that fermentation with S. cerevisiae is an effective method for removing fishy malodor compounds and enhancing the volatile components with fruity, sweet, green, and floral notes in the Saccharina japonica seedling. This process facilitates the elimination of fishy malodor and enhance the fruity, sweet, green, and floral notes of S. japonica seeding and other seaweeds.

Abstract At present, the image encryption algorithm based on the bit‐plane has the problem that the encryption speed and the encryption effect cannot be well balanced. To address the problem, an image layered scrambling encryption algorithm is proposed in this paper. First, a new one‐dimensional Cosine Logistic compound chaotic map (1DCLC) is proposed. Several characteristics of the new chaotic map are analyzed by using various measures, such as bifurcation diagram, Lyapunov exponent, sample entropy etc. And the results show that the novel chaotic map has a better chaotic performance. Second, based on the chaotic map, an image encryption algorithm is proposed. The algorithm first performs an XOR encryption operation on the image. Second, the layered scrambling is applied to the XOR encrypted image. Then the layered and scrambled image is recombined for the second XOR encryption operation. In particular, in the layered scrambling, not only can the position of the pixel be changed but also the value of the pixel can be modified, which improves the security of the algorithm. In addition, in order to defend against various plaintext attacks and increase the security of the overall algorithm, the Hash function is introduced to update the key of the proposed algorithm. Finally, the original algorithm is improved and the improved algorithm's ability to resist differential attacks is analyzed. The experimental simulation and security test results show that the proposed encryption algorithm has a comparable encryption effect and a faster encryption speed.

Water loss is one of the most significant quality deterioration characteristics of passion fruit during postharvest storage, transportation and marketing, which seriously affects its commercial value. In this study, Low Field Nuclear Magnetic Resonance (LF-NMR) was employed to investigate the water loss process of golden passion fruit during storage, and the relationship between water loss and quality deterioration was analyzed. The results of LF-NMR showed that the proton density of the pulp and peel of golden passion fruit decreased significantly during storage, which was consistent with the appearance after severe water loss; additionally, the water loss of fruit was mainly free water with 14.98% decrease, while the bound water decreased significantly in the later stage of storage; and the degree of water loss was related to the process of postharvest ripening and senescence. Further studies showed that there were two respiratory peaks during postharvest ripening period of golden passion fruit, meanwhile the water and weight loss was low, and the decreased chlorophyll content and increased carotenoid content contributed to higher brightness and hue; moreover, the total soluble solids (TSS) content decreased slightly, but titratable acid (TA) and fruit firmness decreased remarkably, indicating a normal postharvest ripening of fruit with rare rot. However, in the senescence period, the respiration rate declined as the water and weight loss increased, and the brightness and hue decreased as the carotenoid reduced rapidly; Furthermore, the TSS and TA contents, and fruit firmness kept decreasing, along with a rapid increase of decay rate. Therefore, the severe water loss of golden passion fruit could not only cause significant loss of weight and freshness, but also induce changes in physiological metabolism, cellular and tissular structure, which reduced fruit storage tolerance and accelerated quality deterioration. This study can provide reference for the study on the mechanism of water loss and corresponding control technology of passion fruit, as well as the non-destructive testing of water status in postharvest fruit and vegetables.

This work evaluated the potential of Camellia pollen extracts as an antioxidant and lipase activity inhibitor from the pollen composition and the extraction solvent. The lipase inhibitory activity, the scavenging radical’s ability (ABTS and DPPH) and the ferric-reducing ability of the seven extracts were examined. The fatty acid profile of the extracts with excellent antioxidant and lipase inhibitory activity was also determined by GC-MS. The ethyl acetate (IC50 = 2.07 ± 0.20 mg/mL) and the acetone extracts (IC50 = 1.19 ± 0.07 mg/mL) showed better lipase inhibitory activity. For the antioxidant activity, the methanol (IC50 = 2.55 ± 0.34 mg/mL), ethanol (IC50 = 2.87 ± 0.23 mg/mL) and the water (IC50 = 2.62 ± 0.05 mg/mL) extracts had superior ABTS radical-scavenging ability. Greater DPPH radical-scavenging ability was seen in the ethanol (IC50 = 2.92 ± 0.04 mg/mL) and acetone extracts (IC50 = 3.09 ± 0.12 mg/mL). The ethyl acetate and petroleum ether extracts manifested better FRAP. The fatty acid composition of the methanol and ethyl acetate extracts belonged to the unsaturated fatty acids. This study indicated that the lipase inhibitory activity and the antioxidant activity found in Camellia pollen may exert dual benefits for preventing and treating obesity.

Intermittent partial discharge has become an essential threat to the safety and stability of high voltage electrical equipment. In order to reduce the sudden insulation breakdown failure due to the intermittent and latent partial discharge of the operating equipment, this paper analyzes the discharge characteristics of the intermittent partial discharge in the constant voltage mode. The UHF partial discharge spectrum of typical intermittent partial discharges is obtained, and the intermittent discharges are divided into low-risk and high-risk categories by adopting PCA and FCM cluster algorithms. Aiming at the characteristics of intermittent partial discharge and the on-line monitoring method of partial discharge, a partial discharge signal collection method based on dynamic frequency is proposed. An intelligent monitoring system of intermittent partial discharge is designed to acquire partial discharge signals initially locate defects. Then the BP neural network method is applied to automatically evaluate and early warn the internal insulation status. The test concluded that the designed monitoring system for intermittent partial discharge could dynamically track and warn the low-risk and high-risk, and evaluate the insulation status of the equipment.

Abstract Background Dandelion is an herb with high nutritional and medicinal values, which has been listed in Chinese Pharmacopeia, European Pharmacopoeia and British Pharmacopoeia, gaining increasing acceptance around the world. However, the current quality control of dandelion is lagging behind. Only in Chinese Pharmacopeia, cichoric acid is used as a marker compound for its quality evaluation, whereas, it can not comprehensively reflect the bioactivity of dandelion. Methods This study developed a strategy by integrating chemometrics with in silico pharmacology to reveal the bioactive markers of dandelion for its quality control. Firstly, the major chemicals in dandelion were characterized using HPLC-DAD-MS/MS, and the corresponding antioxidant and anti-inflammatory activities were evaluated in vitro. Subsequently, the active components were screened by relating the chemicals and bioactivity of dandelion via grey relational assay and partial least squares regression analysis. The potential active components were then subjected to a validation for their activities. Moreover, in silico pharmacology was utilized to evaluate the contribution of active components to efficacy. Results A total of 22 phenolic compounds were characterized. Among them, cichoric acid, caffeic acid and luteolin were identified as quality markers owing to their good correlations with the bioactivities of dandelion. These three markers were quantified in frequently-used dandelion species, viz. Taraxacum mongolicum Hand.-Mazz. (TAM) and T. officinale F. H. Wigg. (TAO). TAM, with acceptably higher content of cichoric acid and caffeic acid, showed better antioxidant activity than TAO. While TAO included higher content of luteolin, presenting slightly more effective in anti-inflammation. Conclusion An useful strategy for the quality marker discovery was successfully designed. And the results provided more knowledge for the quality evaluation of dandelion.

Key points Microbulbifer sp. ALW1 has Laminaria japonica degradation capability. Genomic information of strain ALW1 is useful for analysing the polysaccharides degradation process. Microbulbifer sp. ALW1 could be potentially applied in producing functional materials.

Abstract Phosphate is widely used in surimi products to improve the gel properties. However, excess addition of phosphate occurs, which can harm the consumer's health. This study aimed to evaluate the effects of agar gum and fucoidan on maintaining the gel properties of surimi products instead of phosphate. Interestingly, our results showed that 0.125% of agar gum and fucoidan to replace phosphate could enhance water‐holding capacity and maintain gel strength and textual properties of surimi products well. Especially at frozen storage for 1 year, 0.125% of agar gum reduced the expressible moisture content of surimi products by around 10% (p 0.50% increased the WHC, but significantly decreased gel strength and springiness of surimi products (p

Refined conditions of konjac glucomannan (KGM), physicochemical properties and structural characterization of KGM before and after refining and its blend with κ-carrageenan were explored in this study. Furthermore, the correlation between physicochemical properties of KGM and gel properties of the blend was also determined. The result showed that refined conditions of KGM were as follows: Refined ethanol concentration 60%, swelling time 2 h, swelling temperature 50 ℃. With this treatment, the glucomannan content, viscosity, brightness and whiteness of KGM were increased by 34.43%, 128.55%, 17.94% and 28.29%, respectively. Gel strength, hardness, chewiness and gumminess of its blend with κ-carrageenan were significantly increased by 47.39%, 60.47%, 55.44%, and 45.87%（P < 0.05）, respectively. The best gel properties of the blend were obtained with the enhanced hydrogen bond force, smoother and tighter gel network structure. In addition, physicochemical properties of KGM e.g. glucomannan content, viscosity, color and flavor were considered to be the key factors to improve quality of the blend gel. This study could provide an efficient and simple refined method for development of KGM and carrageenan blend with high gel strength, and lay a theoretical foundation for the industrial production of refined KGM in future.

BackgroundST-segment elevation myocardial infarction (STEMI) patients are at a high residual risk of major adverse cardiovascular events (MACEs) after revascularization. Risk factors modify prognostic risk in distinct ways in different STEMI subpopulations. We developed a MACEs prediction model in patients with STEMI and examined its performance across subgroups.MethodsMachine-learning models based on 63 clinical features were trained in patients with STEMI who underwent PCI. The best-performing model (the iPROMPT score) was further validated in an external cohort. Its predictive value and variable contribution were studied in the entire population and subgroups.ResultsOver 2.56 and 2.84 years, 5.0% and 8.33% of patients experienced MACEs in the derivation and external validation cohorts, respectively. The iPROMPT score predictors were ST-segment deviation, brain natriuretic peptide (BNP), low-density lipoprotein cholesterol (LDL-C), estimated glomerular filtration rate (eGFR), age, hemoglobin, and white blood cell (WBC) count. The iPROMPT score improved the predictive value of the existing risk score, with an increase in the area under the curve to 0.837 [95% confidence interval (CI): 0.784–0.889] in the derivation cohort and 0.730 (95% CI: 0.293–1.162) in the external validation cohort. Comparable performance was observed between subgroups. The ST-segment deviation was the most important predictor, followed by LDL-C in hypertensive patients, BNP in males, WBC count in females with diabetes mellitus, and eGFR in patients without diabetes mellitus. Hemoglobin was the top predictor in non-hypertensive patients.ConclusionThe iPROMPT score predicts long-term MACEs following STEMI and provides insights into the pathophysiological mechanisms for subgroup differences.

Ecological forests are an important part of terrestrial ecosystems, are an important carbon sink and play a pivotal role in the global carbon cycle. At present, the comprehensive utilization of optical and radar data has broad application prospects in forest parameter extraction and biomass estimation. In this study, tree and topographic data of 354 plots in key nature reserves of Liaoning Province were used for biomass analysis. Remote sensing parameters were extracted from Landsat 8 OLI and Sentinel-1A radar data. Based on the strong correlation factors obtained via Pearson correlation analysis, a linear model, BP neural network model and PSO neural network model were used to simulate the biomass of the study area. The advantages of the three models were compared and analyzed, and the optimal model was selected to invert the biomass of Liaoning province. The results showed that 44 factors were correlated with forest biomass (p < 0.05), and 21 factors were significantly correlated with forest biomass (p < 0.01). The comparison between the prediction results of the three models and the real results shows that the PSO-improved neural network simulation results are the best, and the coefficient of determination is 0.7657. Through analysis, it is found that there is a nonlinear relationship between actual biomass and remote sensing data. Particle swarm optimization (PSO) can effectively solve the problem of low accuracy in traditional BP neural network models while maintaining a good training speed. The improved particle swarm model has good accuracy and speed and has broad application prospects in forest biomass inversion.

The extraction of cellulose from the young fruit of Guanxi honey pomelo was studied by ultrasonic assisted alkaline hydrogen peroxide method. On the basis of single factor experiments, taking the cellulose purity as the index, the combination experiment of Design-Expert 8.0 design center was used to optimize the extraction process of cellulose by response surface analysis, the cellulose was analyzed by IR and SEM. The results showed that the change of ultrasonic power had no significant effect on the purity and yield of cellulose, but water bath temperature, ultrasonic time, volume fraction of hydrogen peroxide solution and mass concentration of sodium hydroxide solution had significant effects on the purity and yield of cellulose. The optimum extraction conditions were as follows: Ultrasonic power 200 W, ultrasonic time 40 min, water bath temperature 80 ℃, H2O2 volume fraction 0.9%, NaOH mass concentration 9%. Under these conditions, the predicted value of cellulose purity was 88.48%, and the measured value was 88.95%, under this condition, the yield of cellulose was 17.65%. Infrared analysis showed that cellulose was successfully prepared. SEM analysis showed that the surface structure of cellulose was looser and the gully was deeper than that of Guanxi honey pomelo young fruit before treatment. X-ray diffraction analysis showed that cellulose had type I structure and the crystallinity was 44.26%. This experiment optimized the ultrasonic assisted alkaline hydrogen peroxide extraction process of cellulose from young fruits of Guanxi honey pomelo. It was an efficient and easy to popularize cellulose preparation method, which would provide a reference for the utilization of young fruits of Guanxi honey pomelo and the development of cellulose.

This narrative inquiry traces a Chinese college English teacher’s cognitive transformation in the teaching-research nexus over a 4-year time period from the perspective of sociocultural theory (SCT). Several stories were narrated based on the data from reflective journals, literature reading notes, and interaction notes to show how the participant walked out of the teaching-research contradiction and finally achieved professional development. The findings indicate that the college English teacher’s perception of the research-teaching nexus developed when she actively exercised her agency to take part in social interactions in a supportive sociocultural environment with the regulation of appropriate mediational tools. The conceptual progress in the research-teaching nexus finally contributed to her professional development in both teaching and research. The findings of this study have implications for non-key universities and their academics on how to effectively promote teaching-research integration.

Why do people who seem to be doing well in the workplace occasionally behave badly? Because these employees may be using impression management tactics to create an image. Existing studies have focused on comparing the differences in the use of impression management among different individuals, but cannot explain why a well-behaved individual sometimes behaves badly. Based on the theory of self-control resources, we adopts the survey method of job logs and collects the data of 121 employees. The results show that: (1) the use of self-promotion tactics and ingratiation tactics will promote the depletion of self-control resources. (2) The depletion of self-control resources will encourage employees to engage in counterproductive work behaviors. (3) The effect of self-promotion tactic and ingratiation tactic on the depletion of self-control resources was moderated by emotional intelligence. In the case of high emotional intelligence, this effect is attenuated. And vice versa. (4) Under high emotional intelligence and low emotional intelligence, the indirect effects of self-promotion tactic and ingratiation tactic on employees’ counterproductive work behaviors are significantly different. Our research breaks through the between-individual perspective and illustrates the double-edged sword effect of self-promotion tactic and ingratiation tactic on employee counterproductive work behavior and its mechanism from the internal perspective, which is highly innovative.

In this study, based on the traditional hot water extraction-ethanol precipitation method for fucoidan, the ethanol-free extraction process of kelp fucoidan was studied in accordance with the difference in the fucose contents and sulfate groups of fucoidans and their beneficial biological activities. Three extraction methods including hot water extraction-ethanol precipitation method, hot water extraction-acid precipitation method, and hot water extraction-acid precipitation-enzymatic hydrolysis assisted extraction method, were applied to prepare fucoidans, and three fucoidan samples (sample 1, sample 2 and sample 3) were obtained, respectively. Fucose and sulfuric acid group-contents and biological activities (antioxidant, antibacterial activities) analysis results showed that the contents of fucose and sulfate groups in fucoidan (sample 3) prepared by hot water extraction-acid precipitation-enzymatic assisted hydrolysis method were 41.10%±0.87% and 24.90%±0.15%, respectively, which were significantly higher than the Trade Standard requirements of fucoidan (SC/T 3404-2012), samples 1 and sample 2. Meanwhile, the sample 3 also had the best antioxidant and antibacterial activities in three fucoidan samples. The Response surface methodology (RSM) was used to optimize the key process conditions of hot water extraction-acid precipitation-enzymatic hydrolysis assisted extraction of fucoidan. The best extraction process parameters were obtained as follows: Extraction temperature was 90℃, extraction time was 2.0 h, liquid material ratio was 40:1 mL/g, and the extraction yield reached 9.65%±0.11%. In this study, raction rate of fucoidan and the biological activity of fucoidan prepared by hot water extraction-acid precipitation-enzymatic assisted hydrolysis method were significantly higher than those prepared by hot water extraction-ethanol precipitation method and hot water extraction-acid precipitation method, therefore, the hot water extraction-acid precipitation-enzymatic assisted hydrolysis method digestion would be a good process to effectively replace the hot water extraction-ethanol precipitation method for fucoidan extraction.

Abstract Purpose The microbial community in the pit mud correlated closely with the quality of the final product of Chinese strong-flavored Baijiu (CSFB). However, environmental conditions and brewing processes can vary by region and distilleries. This may lead to differences in microbial composition and function in pit mud. Therefore, revealing the features of the pit mud microbial community structure and functions of different distilleries will provide key information for understanding the diversity and difference of microbes in the brewing of CSFB, which will be beneficial for the improvement of the quality of pit mud and CSFB in the future. Methods and results Illumina MiSeq sequencing of 16S rRNA gene amplicons was used to analyze the similarities and differences in microbial community structure and function in pit muds of different distilleries located in Shihezi (Xinjiang), Xiangyang (Hubei), and Yibin (Sichuan). At the genus level, Clostridium, Lactobacillus, Aminobacterium, Petrimonas, Syntrophomonas, Methanoculleus, Syntrophaceticus, Sedimentibacter, Caloramator, Ruminococcus, Bacillus, Methanosarcina, and Garciella were the dominated genera of pit muds. There were great differences in the composition of microorganisms in pit muds used by different distilleries. The significantly enriched prokaryotic microbiotas of pit muds collected in the distilleries of Xiangyang were mainly affiliated with Bacillus, Lactobacillus, and Croceifilum, and the relative abundance of methanogens, such as Methanomicrobia and Methanobacteria, were only significantly enriched in the pit mud collected from the distilleries of Yibin (P < 0.05). Functional analysis indicated that the difference of microbial composition in pit mud will further lead to significant differences in various metabolic functions. Conclusion The compositions and functions of dominant microorganisms in pit mud used for the production of CSFB by different enterprises across regions in China were greatly different, and there was a close relationship between the compositions and functions of microorganisms in pit mud. Therefore, it may be an effective method to improve CSFB fermentation processes by directionally regulating the microbial community functions of pit mud using specific strains.

In this paper, a new two-dimensional sine-cosine coupling chaos map(2D-SCCM) is proposed. The performance of the proposed two-dimensional chaotic system is analysed by using trajectory distribution maps, Lyapunov exponents, sample entropy and sequence sensitivity, etc. The results show that the 2D-SCCM has better randomness and ergodicity, as well as a wider hyperchaotic range than the existing partial two-dimensional chaos maps. To verify its application in practice, a 2D-SCCM-based color image encryption algorithm is proposed. First, the plain image is used to combine with hash function to generate the key. Then, we construct S-Boxes using the random sequence generated by 2D-SCCM combined with Arnold map. Finally, a color image encryption algorithm is proposed by using the constructed S-Boxes and the chaotic map combined with hash function. Experimental simulations and security tests show that the proposed encryption algorithm has high encryption efficiency and strong security, and can effectively protect images from various attacks.

Aiming at the problems of complex equations, low accuracy, and the strict measurement point layout requirements of the existing electric field integration method, a non-contact measurement method based on the inversion voltage of the near electric field is proposed. Firstly, the field source relationship is clarified, the connection between the spatial electric field and the voltage is derived, and a near-end electric field inversion method is proposed. Secondly, a three-dimensional simulation model of an overhead line is established using COMSOL finite element software, the three-dimensional spatial potential distribution of the overhead line is obtained, and the voltage is inverted and calculated. Finally, an overhead line simulation test platform was built, and MEMS electric field sensors were used for testing and verification. The results show that the maximum error of the three-phase voltage inversion of the proximal electric field measurement is 6.8%, and the error between the voltage obtained by the experimental inversion measurement and the reference voltage is less than 7.2%. The simulation and experimental results also verify the accuracy and feasibility of the inversion voltage of the proximal electric field. The results of this paper can lay a foundation for the practical application of small and miniaturized electric field sensors, and help in the construction and development of smart grids.

ObjectiveDifferent semicircular canal surgery techniques have been used to treat patients with labyrinthine fistulas caused by middle ear cholesteatoma. This study evaluated postoperative hearing and vestibular function after various semicircular canal surgeries.Materials and methodsIn group 1, from January 2008 to December 2014, 29 patients with middle ear cholesteatoma complicated by labyrinthine fistulas were treated with surgery involving covering the fistulas with simple fascia. In group 2, from January 2015 to October 2021, 36 patients with middle ear cholesteatoma complicated by labyrinthine fistulas were included. Cholesteatomas on the surface of type I labyrinthine fistulas were cleaned using the “under water technique” and capped with a “sandwich” composed of fascia, bone meal, and fascia. Cholesteatomas on the surface of type II and III fistulas were cleaned using the “under water technique,” and the labyrinthine fistula was plugged with a “pie” composed of fascia, bone meal, and fascia, and then covered with bone wax.ResultsSome patients with labyrinthine fistulas in group 1 exhibited symptoms of vertigo after surgery. In group 2 Patients with type II labyrinthine fistulas experienced short-term vertigo after semicircular canal occlusion, but no cases of vertigo were reported during long-term follow-up. “sandwich.” In patients with type II labyrinthine fistulas, the semicircular canal occlusion influenced postoperative hearing improvement. However, postoperative patient hearing was still superior to preoperative hearing.ConclusionThe surface of type I labyrinthine fistulas should be capped by a “sandwich” composed of fascia, bone meal, and fascia. Type II and III labyrinthine fistulas should be plugged with a “pie” composed of fascia, bone meal, and fascia, covered with bone wax.

Abstract The presence of sulfate groups in agar compromises the agar quality by affecting the crosslinking during gelling process. Some arylsulfatases can catalyze the hydrolysis of sulfate bonds in agar to improve the agar quality. Immobilized arylsulfatases prove beneficial advantages for their industrial applications. Here, a previously characterized mutant arylsulfatase K253H/H260L was immobilized on the synthesized magnetic Fe3O4 nanoparticles after functionalization by tannic acid (MNPs@TA). The surface properties and molecular structures of the immobilized arylsulfatase (MNPs@TA@ARS) were examined by scanning electron microscopy and Fourier transform infrared spectroscopy. Enzymatic characterization showed that MNPs@TA@ARS exhibited shifted optimal temperature and pH with deviated apparent Km and Vmax compared to its free counterpart. The immobilized arylsulfatase demonstrated improved thermal and pH stability and enhanced storage stability with modest reusability. In addition, MNPs@TA@ARS displayed enhanced tolerance to various inhibitors and detergents. The utilization of the immobilized arylsulfatase for agar desulfation brought the treated agar with improved quality.

Aromatic aldehydes are important industrial raw materials mainly synthesized by anti-Markovnikov (AM) oxidation of corresponding aromatic olefins. The AM product selectivity remains a big challenge. P450 aMOx is the first reported enzyme that could catalyze AM oxidation of aromatic olefins. Here, we reported a rational design strategy based on the “butterfly” model of the active site of P450 aMOx. Constrained molecular dynamic simulations and a binding energy analysis of key residuals combined with an experimental alanine scan were applied. As a result, the mutant A275G showed high AM selectivity of >99%. The results also proved that the “butterfly” model is an effective design strategy for enzymes.

Abstract White tea is a famous Chinese tea that is cooked at boiling point before drinking. The simultaneous distillation‐extraction (SDE) was used to collect volatile compounds during tea cooking. The SDE extract was dominated with green, floral, roasted and woody notes, and weak sweet note. There were 32 volatile compounds identified via gas chromatography–mass spectrometry analysis, and 19 of them had strong fragrance based on the gas chromatography‐olfactometry analyzed results. Hexanal, 2‐hexenal, cis‐3‐hexen‐1‐ol, and camphene were the main contributors to the green note. The floral note was mainly contributed by 2‐hexanone, benzeneacetaldehyde, trans‐linalool oxide, and linalool, and the sweet note was induced by trans‐β‐damascenone. The roasted note was mainly contributed by 2‐pentyl‐furan. The woody note was mainly contributed by trans‐α‐ionone and trans‐β‐ionone. Four putative reaction pathways, including amino acid degradation, carotene degradation, Maillard reaction, and glycosides hydrolysis, were figured out to explain the generation of aromatic‐active volatiles at high temperatures. This study added our knowledge on tea aroma under cooking as well as other thermal treatments.

Abstract A tyrosinase inhibitor was separated from camellia pollen with the aid of solvent fraction, macroporous adsorptive resin chromatography, and high‐speed countercurrent chromatography. The inhibitor was identified to be p‐coumaric acid ethyl ester (p‐CAEE) by nuclear magnetic resonance and mass spectrum. Its inhibitory activity (IC50 = 4.89 μg/ml) was about 10‐fold stronger than arbutin (IC50 = 51.54 μg/ml). The p‐CAEE inhibited tyrosinase in a noncompetitive model with the KI and Km of 1.83 μg/ml and 0.52 mM, respectively. Fluorescence spectroscopy analysis showed the p‐CAEE quenched an intrinsic fluorescence tyrosinase. UV‐Vis spectroscopy analysis showed the p‐CAEE did not interact with copper ions of the enzyme. Docking simulation implied the p‐CAEE induced a conformational change in the catalytic region and thus changed binding forces of L‐tyrosine. Our findings suggest that p‐CAEE plays an important role in inhibiting tyrosinase and provides a reference for developing pharmaceutical, cosmetic, and fruit preservation products using pollen.

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.

The bacterial strain of Microbulbifer sp. ALW1 has demonstrated visible ability of degrading the cell wall of Laminaria japonica, and biochemical characterization has been performed on some individual enzymes to elucidate its genetic basis. However, it still remains elusive how strain ALW1 successfully breaks down the major cell wall component alginate polysaccharide and colonizes on its marine host. In this study, a mass spectrometry-based quantitative analysis of the extracellular and intracellular proteomes was introduced to elucidate the alginate degradation pathway in ALW1 strain. Mass spectrometry and biochemical assays indicated that strain ALW1 could effectively degrade alginate polysaccharide into disaccharides and trisaccharides within 12 h. Proteome analysis identified 156 and 1,047 proteins exclusively localized in extracellular and intracellular compartments, respectively, with 1,086 protein identities of dual localization. Functional annotation of the identified proteins suggested the involvement of diverse catalytic enzymes and non-catalytic molecules for the cleavage and metabolism of alginate polysaccharide. A simplified pathway was constructed to demonstrate the extracellular digestion, active transport, and intracellular conversion of alginate polysaccharide and its fragmented oligosaccharides, casting a picture of genetic loci controlling alginate catabolism by ALW1 strain. This study aims to provide a guide for utilization and genetic manipulation of the bacterial strain ALW1 for efficient alginate oligosaccharides production by fermentation.

Perivascular adipose-derived stem cells (PV-ADSCs) could differentiate into smooth muscle cells (SMCs), participating in vascular remodeling. However, its underlying mechanism is not well explored. Our previous single-cell RNA-sequencing dataset identified a unique expression of matrix Gla protein (MGP) in PV-ADSCs compared with subcutaneous ADSCs. MGP involves in regulating SMC behaviors in vascular calcification and atherosclerosis. In this study, we investigated MGP’s role in PV-ADSCs differentiation toward SMCs in vitro and in vascular remodeling in vivo . PV-ADSCs were isolated from perivascular regions of mouse aortas. Quantitative reverse transcription–polymerase chain reaction (qRT-PCR), Western blot, and immunofluorescence confirmed higher MGP expression in PV-ADSCs. The MGP secretion increased along PV-ADSCs differentiation toward SMCs in response to transforming growth factor–beta 1 (TGF-β1). Lentivirus knockdown of MGP markedly promoted the bone morphogenetic protein 2 (BMP2) expression and phosphorylation of SMAD1/5/8 in PV-ADSCs, subsequently inhibiting its differentiation toward SMCs. Such inhibition could be partially reversed by further application of BMP2 inhibitors. On the contrary, exogenous MGP inhibited BMP2 expression and SMAD1/5/8 phosphorylation in PV-ADSCs, thereby promoting its differentiation toward SMCs. Transplantation of cultured PV-ADSCs, which was pretreated by MGP knockdown, in mouse femoral artery guide-wire injury model significantly alleviated neointimal hyperplasia. In conclusion, MGP promoted the differentiation of PV-ADSCs toward SMCs through BMP2/SMAD-mediated signaling pathway. This study offers a supplement to the society of perivascular tissues and PV-ADSCs.

Astaxanthin is an important natural resource that is widely found in marine environments. Metabolic regulation is an effective method for improving astaxanthin production in Phaffia rhodozyma. Most studies have focused on single regulators, which have limited effects. In this study, 16 metabolic regulators were screened to improve astaxanthin production in high-yield and wild-type strains. Fluconazol and glutamic acid increased astaxanthin volumetric yield in MVP14 by 25.8 and 30.9%, respectively, while ethanol increased astaxanthin volumetric yield in DSM626, 29.3%. Furthermore, six additives that inhibit the competing pathways and promote the main pathway for astaxanthin synthesis were selected for combination treatment. We found that the optimal combination was penicillin, ethanol, triclosan, and fluconazol, which increased astaxanthin cell yield by 51%. Therefore, we suggest that simultaneously promoting the master pathways (mevalonate) and inhibiting competing pathways (fatty acid synthesis and ergosterol) is the best strategy to improve astaxanthin cell yield. Moreover, regulators of the biomass pathway should be avoided to improve cell yield. This study provides a technical basis for the utilisation of astaxanthin in P. rhodozyma.

Objective. Because the response of evaporating light scattering detector (ELSD) being in a nonlinear mode, there is no consensus on the method of calculating its relative correction factors (RCF), which limits the application of the quantitative analysis for multi-components by a single marker (QAMS) with LC-ELSD. Methods. Using eight fructooligosaccharides of Morinda officinalis as a case study, the nystose (GF3) as a single standard was adopted to develop a QAMS method to simultaneously determine the other seven fructooligosaccharides with HILIC-HPLC-ELSD method. Six calculation methods of RCF were investigated to select the most reasonable method. The relative error of content between the QAMS and the external standard method (ESM) obtained from 30 batches of samples was used as an indicator to evaluate the six methods. Finally, a chemometrics analysis was performed to find the differential components among MO and its three processing products. Results. It was first reported that only one calculation method was scientific for calculating RCF for the LC-ELSD method. The RCFs of GF3 to the other seven fructooligosaccharides (GF1–GF8) were obtained as 0.86, 0.91, 0.93, 1.05, 1.15, 1.12, and 1.18, respectively. The QAMS of eight fructooligosaccharides of Morinda officinalis was validated with good linearity (R2 > 0.9998) and accepted the accuracy of 95–105% (RSD

Purpose – The purpose of this paper is to study the operation mechanism of the ecosystem of crowd innovation space. Though the crowd innovation space is a new product of China's innovation-driven strategy, there are some barriers in operation. So, this problem is worthy of study. Design/methodology/approach – In this study, data were obtained through four-month field investigation and semistructured interview, then classified and analyzed through grounded theory, because grounded theory is conducive to the exploration and discovery of new theories. Findings – This study finds that the relationship between makerspace and entrepreneurs is strong social relational embeddedness. The relationship between crowd innovation space and governments and investment institutions is economic relational embeddedness. Under these social network ties, entrepreneurs, crowd innovation space, social investment institutions and so on can interact directly with each other to different degrees, carry out value cocreation activities and improve the benefits of all elements in the ecosystem and the ecosystem itself. Originality/value – This study researches the operation mechanism of crowd innovation space ecosystem and identifies the ties between various elements in the ecosystem on the perspective of social network, which is conducive to improve the self-generating capacity of crowd innovation space and enhance the success rate of entrepreneurship.

BackgroundPerivascular adipose-derived stem cells (PVASCs) can contribute to vascular remodeling, which are also capable of differentiating into multiple cell lineages. The present study aims to investigate the mechanism of PVASC differentiation toward smooth muscle cells (SMCs) and endothelial cells (ECs) as well as its function in neointimal hyperplasia.MethodsSingle-cell sequencing and bulk mRNA sequencing were applied for searching key genes in PVASC regarding its role in vascular remodeling. PVASCs were induced to differentiate toward SMCs and ECs in vitro, which was quantitatively evaluated using immunofluorescence, quantitative real-time PCR (QPCR), and Western blot. Lentivirus transfections were performed in PVASCs to knock down or overexpress TBX20. In vivo, PVASCs transfected with lentivirus were transplanted around the guidewire injured femoral artery. Hematoxylin–eosin (H&E) staining was performed to examine their effects on neointimal hyperplasia.ResultsBulk mRNA sequencing and single-cell sequencing revealed a unique expression of TBX20 in PVASCs. TBX20 expression markedly decreased during smooth muscle differentiation while it increased during endothelial differentiation of PVASCs. TBX20 knockdown resulted in the upregulation of SMC-specific marker expression and activated Smad2/3 signaling, while inhibiting endothelial differentiation. In contrast, TBX20 overexpression repressed the differentiation of PVASCs toward smooth muscle cells but promoted endothelial differentiation in vitro. Transplantation of PVASCs transfected with TBX20 overexpression lentivirus inhibited neointimal hyperplasia in a murine femoral artery guidewire injury model. On the contrary, neointimal hyperplasia significantly increased in the TBX20 knockdown group.ConclusionA subpopulation of PVASCs uniquely expressed TBX20. TBX20 could regulate SMC and EC differentiation of PVASCs in vitro. Transplantation of PVASCs after vascular injury suggested that PVASCs participated in neointimal hyperplasia via TBX20.

Objective: Corticosterone causes significant neurotoxicity in primary hippocampal neurons which is associated with depression. Dysfunctional autophagy is implicated in cognitive impairment and depressive-like behavior. The traditional Chinese medicine Sinisan (SNS) is highly effective in clinical treatment of depression. However, the molecular mechanisms underlying therapeutic effects of SNS are unknown.Purpose: The aim of this study was to elucidate the protective effect of SNS and the underlying mechanisms against corticosterone-induced neuronal damage.Study Design: The effects of serum derived from rats containing SNS (or untreated controls) on the expression of autophagy-related molecules in primary rat hippocampal neurons exposed to different concentrations of corticosterone for different intervals were explored.Methods: CCK-8 assay, LDH assay were used to analyze cell viability and LDH activity. Western blot, qRT-PCR, and immunofluorescence assays were used to determine protein and mRNA expression levels of molecules such as LC3, p62, Beclin1, ULK1, PI3K, p-PI3K, Akt p-Akt, mTOR, p-mTOR, p70S6, p-p70S6, 4ebp1 and p-4ebp1.Results: Corticosterone induced a dose- and time-dependent reduction in cellular viability. Moreover, corticosterone (100–400 μM) treatment for 24 h increased LC3-II/LC3-I protein ratio, increased Beclin1 and ULK1 protein expression levels, and decreased p62, PI3K, p-PI3K, p-Akt, p-mTOR, p-p70S6, and p-4ebp1 protein expression levels. Notably, SNS-containing serum reversed corticosterone-induced reduction of neuronal viability, and increased p62, PI3K, p-Akt, p-mTOR, p-p70S6, and p-4ebp1 protein and mRNA expression levels. In addition, SNS-containing serum decreased LC3-II/LC3-I protein ratio, and downregulated Beclin1, and ULK1 protein and mRNA expression in primary hippocampal neurons.Conclusion: SNS protects primary hippocampal neurons against corticosterone-induced neurotoxicity by preventing excessive autophagy through activation of PI3K/AKT/mTOR pathway.

The arc suppression coil determines whether it can effectively extinguish the arc when it is grounded in the neutral non-effective grounding system. An artificial grounding test is an importantway to verify its performance. In this study, 13 substations with the 10 kV system in the Ningxia areawere selected and considered. Based on the artificial single-phase grounding test, the residual current, the compensation current and the off-resonance degree were measured in the arc suppression coil, and the performance of the arc suppression coil in the 10 kV system was verified. The experimental results show that the error of arc suppression coil automatic measurement is large, the off-resonance degree is large, the resistive component in the compensation current is excessive, the harmonic component exists in the compensating current and capacitive current. To solve these problems, this paper puts forward the corresponding countermeasures for reference.

Abstract Biosynthesis of secondary metabolites in actinobacteria is regulated by complex regulatory mechanisms on responding environmental changes. In this study, we have identified a two-component system (TCS) designated as RimA1A2 in the genome of Streptomyces rimosus M4018, with high homology to the TCS RapA1A2 from Streptomyces coelicolor, known for its positive regulatory function towards actinorhodin (ACT) biosynthesis. Using RT-PCR analysis, we demonstrate that rimA1 encodes response regulator (RR) and rimA2 encoding histidine kinase (HK) from S. rimosus that are co-transcribed as a single-polycistronic mRNA. When S. rimosus was cultivated on standard media, no significant difference in culture growth or morphological properties was observed between the rimA1-disrupted mutant and parent strain M4018. However, the rimA1-disrupted strain displayed significant increase in oxytetracycline (OTC) titer when cultivated in minimal medium (MM) containing glycine as sole nitrogen source, and the transcription of selected genes involved in OTC biosynthesis was increased, supporting the hypothesis that RimA1A2 has a negative regulatory role in OTC biosynthesis via global regulation. We observed an increased resistance of the rimA1-disrupted mutant strain to selected antibiotics. Interestingly, in the rimA1-disrupted strain, OTC biosynthesis was affected under different environmental stress conditions such as osmotic and oxidative stress. Accordingly, this phenotype was observed in a medium-dependent manner. Considering complexity of regulatory networks in antibiotic-producing organisms, this study demonstrates the importance of cultivation conditions, which is often neglected.

Chondroitinase plays an important role in structural and functional studies of chondroitin sulfate (CS). In this study, a new member of chondroitinase B of PL6 family, namely ChSase B6, was cloned from marine bacterium Microbulbifer sp. ALW1 and subjected to enzymatic and structural characterization. The recombinant ChSase B6 showed optimum activity at 40 °C and pH 8.0, with enzyme kinetic parameters of Km and Vmax against chondroitin sulfate B (CSB) to be 7.85 µg/mL and 1.21 U/mg, respectively. ChSase B6 demonstrated thermostability under 60 °C for 2 h with about 50% residual activity and good pH stability under 4.0–10.0 for 1 h with above 60% residual activity. In addition, ChSase B6 displayed excellent stability against the surfactants including Tween-20, Tween-80, Trion X-100, and CTAB. The degradation products of ChSase B6-treated CSB exhibited improved antioxidant ability as a hydroxyl radical scavenger. Structural analysis and site-directed mutagenesis suggested that the conserved residues Lys248 and Arg269 were important for the activity of ChSase B6. Characterization, structure, and molecular dynamics simulation of ChSase B6 provided a guide for further tailoring for its industrial application for chondroitin sulfate bioresource development.

The hypoglycaemic effect of all-trans astaxanthin is long known for its antioxidation for type 2 diabetes, a global health concern. To reduce glycaemic index of type 2 diabetes, inhibition of key enzymes is an efficient approach, for example to inhibit α-glucosidase. Conventional chemical or synthetic enzyme-inhibitors have adverse side effects. Therefore, we studied the inhibition of α-glucosidase by all-trans astaxanthin. To inhibit α-glucosidase, the half maximal inhibitory concentration (IC50) of all-trans astaxanthin was 67.95 ± 0.03 μmol/L. All-trans astaxanthin inhibited α-glucosidase as a competitive inhibitor, as shown by kinetic analysis. All-trans astaxanthin could induce the changes of the secondary structure to reduce α-glucosidase activity. Molecular-docking analysis reveals that all-trans astaxanthin prevented substrate from binding to α-glucosidase by occupying the space of the active pocket to cause the inhibition. Our findings suggest that all-trans astaxanthin has the hypoglycaemic effect through inhibiting α-glucosidase, in addition to its antioxidation effect reported earlier.

Alzheimer´s disease is a global neurodegenerative health concern. To prevent the disease, the simultaneous inhibition of acetylcholinesterase and oxidative stress is an efficient approach. In this study, the inhibition effect of all-trans astaxanthin mainly from marine organisms on acetylcholinesterase and oxidative stress was evaluated by a chemical-based method in vitro and cell assay model. The results show that all-trans astaxanthin was a reversible competitive inhibitor and exhibited a strong inhibition effect with half inhibitory concentration (IC50 value) of 8.64 μmol/L. Furthermore, all-trans astaxanthin inhibited oxidative stress through reducing malondialdehyde content and increasing the activity of superoxide dismutase as well as catalase. All-trans astaxanthin could induce the changes of the secondary structure to reduce acetylcholinesterase activity. Molecular-docking analysis reveals that all-trans astaxanthin prevented substrate from binding to acetylcholinesterase by occupying the space of the active pocket to cause the inhibition. Our finding suggests that all-trans astaxanthin might be a nutraceutical supplement for Alzheimer´s disease prevention.

Pomelo fruitlets have the potential for extracting cellulose. This study aimed to investigate characterization and functionality of cellulose extracted from pomelo fruitlets by different extraction methods. Cellulose extracted by acidic-alkaline hydrogen peroxide hydrolysis (CAA), alkaline hydrogen peroxide hydrolysis (CA), and ultrasonic assisted alkaline hydrogen peroxide hydrolysis (CUA) were prepared from pomelo fruitlets. The results showed that cellulose CUA had higher yield and purity with higher crystallinity and smaller particle size than those of CAA or CA (p < 0.05). Specifically, the yield of CUA was 82.75% higher than that of CAA, and purity was increased by 26.42%. Additionally, water- and oil-holding capacities of CUA were superior to those of CAA or CA, increasing by 13–23% and 10–18%, respectively. The improvement of water- and oil-holding capacities were highly related to its smaller particle size with increased surface area. The results suggested that ultrasonic assisted alkaline hydrogen peroxide hydrolysis is a promising and efficient method to prepare high-purity cellulose from pomelo fruitlets, and this cellulose is expected to be a food stabilizer and pharmaceutical additive.

In this study, the polysaccharide ascophyllan, isolated from Ascophyllum nodosum, was degraded using alginate lyase (EC 4.2.2.3) to prepare low-molecular-weight fragments. LMWAs-L, an extremely low-molecular-weight saccharide (6.71 kDa) with low fucose- and sulphate-contents, was purified by gel filtration chromatography. LMWAs-L exhibited significant macrophage-stimulating activities, similar to ascophyllan, through intracellular signalling pathways. Methylation and GC/MS analyses indicated that the main glycosidic linkages of LMWAs-L were 1,2-linked-GlcpA, followed by T-linked-Glcp, 1,3,6-linked-Galp, 1,3-linked-Fucp, 1,4-linked-Xylp, and 1,4-linked-ManpA at a molar ratio of 3.37: 1.13: 1.11: 1.00: 0.96: 0.61. The proposal repeating structure of LMWAs-L was shown to be →2)-α-D-GlcpA-(1 → 2)-α-D-GlcpA-(1 → 6)-α-D-Galp-(1 → 2)-α-D-GlcpA-(1→ as main chain, branched by T-α-D-Glcp-(1 → 4)-β-D-Xylp-(1 → 3)-α-L-Fucp4S-(1→ at the O-3 of 3,6)-α-D-Galp-(1→ residues. 4-deoxy-L-erythro-hex-4-enuronosyluronate-4-β-D-ManpA-(1→ and →4)-β-D-ManpAred residues were attached to the ends of main chain as non-reducing end residue and reducing end residue, respectively. Our results suggest that the fragment LMWAs-L contain an essential structural element of ascophyllan that is responsible for the macrophage-stimulating activities.

Background Oral squamous cell carcinoma (OSCC) is a major lethal malignant cancer of the head and neck region, yet its molecular mechanisms of tumourigenesis are still unclear. Patients and methods We performed weighted gene co-expression network analysis (WGCNA) on RNA-sequencing data with clinical information obtained from The Cancer Genome Atlas (TCGA) database. The relationship between co-expression modules and clinical traits was investigated by Pearson correlation analysis. Furthermore, the prognostic value and expression level of the hub genes of these modules were validated based on data from the TCGA database and other independent datasets from the Gene Expression Omnibus (GEO) database and the Human Protein Atlas database. The significant modules and hub genes were also assessed by functional analysis and gene set enrichment analysis (GSEA). Results We found that the turquoise module was strongly correlated with pathologic T stage and significantly enriched in critical functions and pathways related to tumourigenesis. PPP1R12B, CFD, CRYAB, FAM189A2 and ANGPTL1 were identified and statistically validated as hub genes in the turquoise module and were closely implicated in the prognosis of OSCC. GSEA indicated that five hub genes were significantly involved in many well-known cancer-related biological functions and signaling pathways. Conclusion In brief, we systematically discovered a co-expressed turquoise module and five hub genes associated with the pathologic T stage for the first time, which provided further insight that WGCNA may reveal the molecular regulatory mechanism involved in the carcinogenesis and progression of OSCC. In addition, the five hub genes may be considered candidate prognostic biomarkers and potential therapeutic targets for the precise early diagnosis, clinical treatment and prognosis of OSCC in the future.

Astaxanthin is a natural pigment that possesses benefit potentials to prevent obesity, however, its underlying mechanism is not clarified. In the current study, Phaffia rhodozyma astaxanthin was prepared and its inhibitory effect on pancreatic lipase was evaluated. The results showed that astaxanthin significantly inhibited the activity of pancreatic lipase in a dose-dependent manner within the tested concentration ranges. The kinetic analysis demonstrated that astaxanthin noncompetitively inhibited pancreatic lipase activity. In addition, astaxanthin induced secondary structure changes which resulted in decreased enzyme activities. Furthermore, the molecular docking analysis revealed that astaxanthin blocked the channel of catalytic site to delay substrate entrance or prevent product diffusion through changing the catalytic site conformation. These findings not only shed light on the underlying inhibitory mechanism of astaxanthin on pancreatic lipase, but also provide scientific evidence for extending the application of astaxanthin in functional food industries.

Abstract Background High amounts of insoluble substrates exist in the traditional solid-state fermentation (SSF) system. The presence of these substrates complicates the determination of microbial biomass. Thus, enzyme activity is used as the sole index for the optimization of the traditional SSF system, and the relationship between microbial growth and enzyme synthesis is always ignored. This study was conducted to address this deficiency. All soluble nutrients from tea stalk were extracted using water. The aqueous extract was then mixed with polyurethane sponge to establish a modified SSF system, which was then used to conduct tannase production. With this system, biomass, enzyme activity, and enzyme productivity could be measured rationally and accurately. Thus, the association between biomass and enzyme activity could be easily identified, and the shortcomings of traditional SSF could be addressed. Results Different carbon and nitrogen sources exerted different effects on microbial growth and enzyme production. Single-factor experiments showed that glucose and yeast extract greatly improved microbial biomass accumulation and that tannin and (NH4)2SO4 efficiently promoted enzyme productivity. Then, these four factors were optimized through response surface methodology. Tannase activity reached 19.22 U/gds when the added amounts of tannin, glucose, (NH4)2SO4, and yeast extract were 7.49, 8.11, 9.26, and 2.25%, respectively. Tannase activity under the optimized process conditions was 6.36 times higher than that under the initial process conditions. The optimized parameters were directly applied to the traditional tea stalk SSF system. Tannase activity reached 245 U/gds, which is 2.9 times higher than our previously reported value. Conclusions In this study, a modified SSF system was established to address the shortcomings of the traditional SSF system. Analysis revealed that enzymatic activity and microbial biomass are closely related, and different carbon and nitrogen sources have different effects on microbial growth and enzyme production. The maximal tannase activity was obtained under the optimal combination of nutrient sources that enhances cell growth and tannase accumulation. Moreover, tannase production through the traditional tea stalk SSF was markedly improved when the optimized parameters were applied. This work provides an innovative approach to bioproduction research through SSF.

Background: A new ι-carrageenase-producing strain was screened from mangroves and authenticated as Pseudoalteromonas carrageenovora ASY5 in our laboratory. The potential application of this new strain was evaluated. Results: Medium compositions and culturing conditions in shaking flask fermentation were firstly optimized by single-factor experiment. ι-Carrageenase activity increased from 0.34 U/mL to 1.08 U/mL after test optimization. Optimal fermentation conditions were 20°C, pH 7.0, incubation time of 40 h, 15 g/L NaCl, 1.5% (w/v) yeast extract as nitrogen source, and 0.9% (w/v) ι-carrageenan as carbon source. Then, the crude ι-carrageenase was characterized. The optimum temperature and pH of the ι-carrageenase were 40°C and 8.0, respectively. The enzymatic activity at 35–40°C for 45 min retained more than 40% of the maximum activity. Meanwhile, The ι-carrageenase was inhibited by the addition of 1 mmol/L Cd2+ and Fe3+ but increased by the addition of 1 mmol/L Ag+, Ba2+, Ca2+, Co2+, Mn2+, Zn2+, Fe2+, and Al3+. The structure of oligosaccharides derived from ι-carrageenan was detected using electrospray ionization mass spectrometry (ESI-MS). The ι-carrageenase degraded ι-carrageenan, yielding disaccharides and tetrasaccharides as main products. Conclusions: The discovery and study of new ι-carrageenases are beneficial not only for the production of ι-carrageenan oligosaccharides but also for the further utilization in industrial production. Keywords: Disaccharides, Electrospray ionization mass spectrometry (ESI-MS), Enzyme properties, Fermentation optimization, Galactans, Pseudoalteromonas carrageenovora, Sulfated linear polysaccharides, Tetrasaccharides, ι-Carrageenan oligosaccharides, ι-Carrageenan, ι-Carrageenase-producing strain

Background: Inferior Tieguanyin oolong tea leaves were treated with tannase. The content and bioactivity of catechins in extracts from the treated tea leaves were investigated to assess the improvement in the quality of inferior Tieguanyin oolong tea. Results: Analysis showed that after treatment, the esterified catechin content decreased by 23.5%, whereas non-galloylated catechin and gallic acid contents increased by 15.3% and 182%, respectively. The extracts from tannase-treated tea leaves showed reduced ability to bind to BSA and decreased tea cream levels. The extracts also exhibited increased antioxidant ability to scavenge OH and DPPH radicals, increased ferric reducing power, and decreased inhibitory effects on pancreatic α-amylase and lipase activities. Conclusions: These results suggested that tannase treatment could improve the quality of inferior Tieguanyin oolong tea leaves.

Background: A simple and efficient strategy for agarase immobilization was developed with carboxyl-functionalized magnetic nanoparticles (CMNPs) as support. The CMNPs and immobilized agarase (agarase-CMNPs) were characterized by transmission electron microscopy, dynamic light scattering, vibrating sample magnetometry, scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and zeta-potential analysis. The hydrolyzed products were separated and detected by ESI-TOF-MS. Results: The agarase-CMNPs exhibited a regular spherical shape with a mean diameter of 12 nm, whereas their average size in the aqueous solution was 43.7 nm as measured by dynamic light scattering. These results indicated that agarase-CMNPs had water swelling properties. Saturation magnetizations were 44 and 29 emu/g for the carriers and agarase-CMNPs, respectively. Thus, the particles had superparamagnetic characteristics, and agarase was successfully immobilized onto the supports. Agaro-oligosaccharides were prepared with agar as substrate using agarase-CMNPs as biocatalyst. The catalytic activity of agarase-CMNPs was unchanged after six reuses. The ESI-TOF mass spectrogram showed that the major products hydrolyzed by agarase-CMNPs after six recycle uses were neoagarotetraose, neoagarohexaose, and neoagarooctaose. Meanwhile, the end-products after 90 min of enzymatic treatment by agarase-CMNPs were neoagarobiose and neoagarotetraose. Conclusions: The enhanced agarase properties upon immobilization suggested that CMNPs can be effective carriers for agarase immobilization. Agarase-CMNPs can be remarkably used in developing systems for repeated batch production of agar-derived oligosaccharides.

Bee pollen is an important bee-product that contains larger amount of bioactive compounds. In this paper, a tyrosinase inhibitor was separated from camellia pollen by the aid of high-speed counter-current chromatography (HSCCC), macroporous adsorptive resin chromatography and solvent fraction. The tyrosinase inhibitor was identified to be kaempferol by absorption spectrum, nuclear magnetic resonance and mass spectrum. The purity and recovery were 98.47% and 41.94%, respectively. The kaempferol was detected to have the IC50 of 0.05 mg/mL and mainly exists in glycoside forms. It had a concentration of 1.03 mg/g in the acidic hydrolysis of the ethanol extract (HEE), and contributed 32.41% to the total tyrosinase inhibition activity of HEE. This study demonstrates an effective procedure to purify bioactive compounds from bee pollen, and reveals kaempferol as a major tyrosinase inhibitor of camellia pollen, providing interesting information for in-depth study of bioactive compounds of pollen.