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ObjectivesBifunctional alginate lyase can efficiently saccharify alginate biomass and prepare functional oligosaccharides of alginate.ResultsA new BP-2 strain that produces alginate lyase was screened and identified from rotted Sargassum. A new alginate lyase, Alg17B, belonging to the polysaccharide lyase family 17, was isolated and purified from BP-2 fermentation broth by freeze-drying, dialysis, and ion exchange chromatography. The enzymatic properties of the purified lyase were investigated. The molecular weight of Alg17B was approximately 77 kDa, its optimum reaction temperature was 40–45 °C, and its optimum reaction pH was 7.5–8.0. The enzyme was relatively stable at pH 7.0–8.0, with a temperature range of 25–35 °C, and the specific activity of the purified enzyme reached 4036 U/mg. A low Na+ concentration stimulated Alg17B enzyme activity, but Ca2+, Zn2+, and other metal ions inhibited it. Substrate specificity analysis, thin-layer chromatography, and mass spectrometry showed that Alg17B is an alginate lyase that catalyses the hydrolysis of sodium alginate, polymannuronic acid (polyM) and polyguluronic acid to produce monosaccharides and low molecular weight oligosaccharides. Alg17B is also bifunctional, exhibiting both endolytic and exolytic activities toward alginate, and has a wide substrate utilization range with a preference for polyM.ConclusionsAlg17B can be used to saccharify the main carbohydrate, alginate, in the ethanolic production of brown algae fuel as well as in preparing and researching oligosaccharides.

Alginate lyases are a group of enzymes that catalyze the depolymerization of alginates into oligosaccharides or monosaccharides. These enzymes have been widely used for a variety of purposes, such as producing bioactive oligosaccharides, controlling the rheological properties of polysaccharides, and performing structural analyses of polysaccharides. The algM4 gene of the marine bacterium Vibrio weizhoudaoensis M0101 encodes an alginate lyase that belongs to the polysaccharide lyase family 7 (PL7). In this study, the kinetic constants Vmax (maximum reaction rate) and Km (Michaelis constant) of AlgM4 activity were determined as 2.75 nmol/s and 2.72 mg/mL, respectively. The optimum temperature for AlgM4 activity was 30 °C, and at 70 °C, AlgM4 activity dropped to 11% of the maximum observed activity. The optimum pH for AlgM4 activity was 8.5, and AlgM4 was completely inactive at pH 11. The addition of 1 mol/L NaCl resulted in a more than sevenfold increase in the relative activity of AlgM4. The secondary structure of AlgM4 was altered in the presence of NaCl, which caused the α-helical content to decrease from 12.4 to 10.8% and the β-sheet content to decrease by 1.7%. In addition, NaCl enhanced the thermal stability of AlgM4 and increased the midpoint of thermal denaturation (Tm) by 4.9 °C. AlgM4 exhibited an ability to degrade sodium alginate, poly-mannuronic acid (polyM), and poly-guluronic acid (polyG), resulting in the production of oligosaccharides with a degree of polymerization (DP) of 2–9. AlgM4 possessed broader substrate, indicating that it is a bifunctional alginate lyase. Thus, AlgM4 is a novel salt-activated and bifunctional alginate lyase of the PL7 family with endolytic activity.

Herpes simplex encephalitis (HSE) caused by HSV-1 is the most common non-epidemic viral encephalitis, and the neuropathogenesis of HSE remains elusive. This work describes a 3D human neurovascular unit (NVU) model that allows to explore the neuropathogenesis of HSE in vitro. This model is established by co-culturing human microvascular endothelial cells, astrocytes, microglia and neurons on a multi-compartment chip. Upon HSV-1 infection, this NVU model exhibited HSE-associated pathological changes, including cytopathic effects, blood-brain barrier dysfunction and pro-inflammatory cytokines release. Besides, significant innate immune responses were observed with the infiltration of peripheral immune cells and microglial activation. Transcriptomic analysis revealed broadly inflammatory and chemotactic responses in host cells. Mechanistically, we found HSV-1 could induce severe suppression of autophagic flux in glial cells, especially in microglia. Autophagy activators could effectively inhibit HSV-1 replication and rescue neurovascular injuries, indicating the utility of this unique platform for studying neurological diseases and new therapeutics. Herpes simplex encephalitis caused by HSV-1 is a common viral encephalitis with severe symptoms and poor prognosis. Here, the authors developed a new 3D human neurovascular unit (NVU) model in vitro that allows to probe the neuropathogenesis and therapeutics of HSV-1-associated encephalitis.

Alzheimer’s disease (AD) is characterized by progressive synaptic dysfunction, neuronal death, and brain atrophy, with amyloid-β (Aβ) plaque deposits and hyperphosphorylated tau neurofibrillary tangle accumulation in the brain tissue, which all lead to loss of cognitive function. Pathogenic mutations in the well-known AD causal genes including APP , PSEN1 , and PSEN2 impair a variety of pathways, including protein processing, axonal transport, and metabolic homeostasis. Here we identified a missense variant rs117916664 (c.896T>C, p.Asn299Ser [p.N299S]) of the acetyl-CoA acyltransferase 1 ( ACAA1 ) gene in a Han Chinese AD family by whole-genome sequencing and validated its association with early-onset familial AD in an independent cohort. Further in vitro and in vivo evidence showed that ACAA1 p.N299S contributes to AD by disturbing its enzymatic activity, impairing lysosomal function, and aggravating the Aβ pathology and neuronal loss, which finally caused cognitive impairment in a murine model. Our findings reveal a fundamental role of peroxisome-mediated lysosomal dysfunction in AD pathogenesis.

Background Dental staff were characterized with the tolerance of enduring stress and they are at a high risk to respiratory infectious disease. This study compared the anxiety level of the frontline dental staff (FDS) to the general public in Yichang during the coronavirus disease of 2019 (COVID-19) pandemic and examined potential explanatory factors to the differences. Methods Two online questionnaires were used separately to collect data from FDS and the general public. The Chinese version of Beck Anxiety Inventory (BAI) was included for the assessment of anxiety. Firstly, a Chi-square test was conducted to compare the anxiety state between these two groups. Then, a bivariate analysis using Cramer’s V and Eta squared was conducted to find the potential factors. Lastly, a binary logistic regression was performed to examine the association between potential factors and the anxiety state of FDS. Results In general, FDS were 4.342 (95% CI: 2.427–7.768) times more likely to suffer from anxiety disorders than the general public. The bivariate analysis showed that age, Level Three Protective Measures (PM-3), conflicts with patients and/or colleagues were moderately associated with the anxiety state of FDS. But the knowledge of COVID-19, the treatment to suspected or confirmed cases both had a weak association with the anxiety among FDS. Conversely, workload, the exposure to potential infectious substance and conducting aerosol generated performance were not significantly related to the anxiety of FDS. As the model indicated, an elder age and PM-3 protective measures could lower the anxiety state of FDS, whereas the conflict with patients or/and colleagues would worsen it. Conclusions During the COVID-19 pandemic, FDS were more likely to suffer from anxiety disorders than the general public. An elder age, sufficient personal protective measures and good relationships with colleagues and patients would help them to maintain good mental health.

Background Life’s Simple 7 (LS7), developed by the American Heart Association, addresses seven key health behaviors and relationship factors. Although LS7 has been studied in relation to various chronic diseases, its association with arthritis remains unclear. This study seeks to investigate the association between LS7 and arthritis, with particular emphasis on the mediating role of body fat percentage (BFP). Methods Data from the 2011–2018 National Health and Nutrition Examination Survey (NHANES), including 16,332 adult participants, were analyzed. The connection between LS7 and arthritis was evaluated using multivariable logistic regression, smooth curve fitting, and subgroup analysis. Mediation analysis assessed the role of BFP in this relationship. Additionally, ROC curve analysis was used to assess the predictive performance of the model, and the Boruta algorithm identified the influential factors associated with arthritis. Results After adjusting for relevant covariables, each standard deviation increase in LS7 was linked to a 13% lower likelihood of arthritis [OR = 0.87, 95% CI: 0.84, 0.89]. Participants in the highest LS7 tertile (T3) exhibited a 50% reduced likelihood of developing arthritis compared to those in the lowest tertile (T1) [OR = 0.50, 95% CI: 0.43, 0.60]. Mediation analysis confirmed that BFP significantly mediated the LS7-arthritis relationship. Furthermore, the Boruta algorithm identified LS7 and BFP as key variables associated with arthritis. Conclusion Elevated LS7 scores were associated with a lower likelihood of arthritis, with BFP serving as a mediating factor. Improving LS7 scores and managing body fat may help prevent arthritis. Due to the study’s cross-sectional design, causality cannot be confirmed. Future research should use longitudinal studies to verify these findings and target high-risk groups.

The Laves phase formed during the long-term creep of 9% Cr heat-resistant steels plays an important role in their high-temperature mechanical properties. Detecting and quantifying the Laves phase is one of the main problems in predicting the creep residual life. This study detects and quantifies the Laves phase in various 9% Cr heat-resistant steel samples by anodic polarization. Both T92/P92 samples after creep and 9Cr ferritic martensitic samples after thermal ageing precipitate Laves phase particles, and the content of the Laves phase increases with the service time. Comparing the results obtained by the electrochemical method with those obtained by the traditional SEM observation method, it can be found that there is a similar two-stage linear relationship between the two results in all materials, which is related to the diameter change of Laves phase particles during service. According to the correlation between the Laves phase content and creep time, an extrapolation method for the prediction of the residual creep life is proposed. The results show that the creep life of P92 can be predicted by using the dissolved charge density of the Laves phase with high prediction accuracy. This method has the potential to evaluate the service states of materials and predict the long-term creep life in the industrial field.

Background Life's Simple 7 (LS7), developed by the American Heart Association, addresses seven key health behaviors and relationship factors. Although LS7 has been studied in relation to various chronic diseases, its association with arthritis remains unclear. This study seeks to investigate the association between LS7 and arthritis, with particular emphasis on the mediating role of body fat percentage (BFP). Methods Data from the 2011-2018 National Health and Nutrition Examination Survey (NHANES), including 16,332 adult participants, were analyzed. The connection between LS7 and arthritis was evaluated using multivariable logistic regression, smooth curve fitting, and subgroup analysis. Mediation analysis assessed the role of BFP in this relationship. Additionally, ROC curve analysis was used to assess the predictive performance of the model, and the Boruta algorithm identified the influential factors associated with arthritis. Results After adjusting for relevant covariables, each standard deviation increase in LS7 was linked to a 13% lower likelihood of arthritis [OR = 0.87, 95% CI: 0.84, 0.89]. Participants in the highest LS7 tertile (T3) exhibited a 50% reduced likelihood of developing arthritis compared to those in the lowest tertile (T1) [OR = 0.50, 95% CI: 0.43, 0.60]. Mediation analysis confirmed that BFP significantly mediated the LS7-arthritis relationship. Furthermore, the Boruta algorithm identified LS7 and BFP as key variables associated with arthritis. Conclusion Elevated LS7 scores were associated with a lower likelihood of arthritis, with BFP serving as a mediating factor. Improving LS7 scores and managing body fat may help prevent arthritis. Due to the study's cross-sectional design, causality cannot be confirmed. Future research should use longitudinal studies to verify these findings and target high-risk groups. Keywords: Life's simple 7, Arthritis, Body fat percentage, Mediation analysis, NHANES

Doublecortin (DCX) is transiently expressed in new-born neurons in the subventricular zone (SVZ) and subgranular zone (SGZ) related to adult neurogenesis in the olfactory bulb (OB) and hippocampal formation. DCX immunoreactive (DCX+) immature neurons also occur in the cerebral cortex primarily over layer II and the amygdala around the paralaminar nucleus (PLN) in various mammals, with interspecies differences pointing to phylogenic variation. The tree shrews ( Tupaia belangeri ) are phylogenetically closer to primates than to rodents. Little is known about DCX+ neurons in the brain of this species. In the present study, we characterized DCX immunoreactivity (IR) in the forebrain of Chinese tree shrews aged from 2 months- to 6 years-old ( n = 18). DCX+ cells were present in the OB, SVZ, SGZ, the piriform cortex over layer II, and the amygdala around the PLN. The numerical densities of DCX+ neurons were reduced in all above neuroanatomical regions with age, particularly dramatic in the DG in the 5–6 years-old animals. Thus, DCX+ neurons are present in the two established neurogenic sites (SVZ and SGZ) in the Chinese tree shrew as seen in other mammals. DCX+ cortical neurons in this animal exhibit a topographic pattern comparable to that in mice and rats, while these immature neurons are also present in the amygdala, concentrating around the PLN as seen in primates and some nonprimate mammals.

Nutritional, structural and functional properties of proteins from tiger nut seed meal (TNPF) were investigated in this study. Four kinds of TNPF, albumin (ALB), globulin (GLO), glutelin (GLU), and prolamin (PRO) were obtained through Osborne extraction method, comprising 42.37%, 6.23%, 31.25%, and 5.10% of the total TNPF, respectively. The ratios of essential amino acids to total amino acids in ALB, GLO, GLU and PRO were 43.60%, 38.29%, 42.39%, and 42.82%, respectively. Our results revealed that GLO exhibited the highest in vitro protein digestibility (86.51%), followed by ALB (81.68%), PRO (75.73%), and GLU (60.52%). Further, the analysis of Fourier transform infrared spectroscopy, intrinsic fluorescence spectra, and surface hydrophobicity indicated that the secondary structure and ternary conformation of the four kinds of TNPF were significantly different. Moreover, four kinds of TNPF exhibited their highest solubility, foaming capacity and emulsifying stability under alkaline condition (pH = 12.0) and the lowest near the isoelectric points. Additionally, GLU exhibited the highest foaming ability, emulsification property, and water/oil holding capacity, while ALB showed the highest thermal stability. These findings suggested that GLU extracted from tiger nut seed meal demonstrated excellent nutritional and functional properties, making it a promising food additive to enhance food quality.