Desaminotyrosine is a redox-active microbial metabolite that bolsters macrophage antimicrobial functions while attenuating IL-6 production.

Intestinal microbiota contributes to host defense against pathogens while avoiding the induction of inflammation in homeostatic conditions, but the mechanism is not fully understood. To investigate the potential role of the bacterial metabolite desaminotyrosine (DAT) in regulating host defense and inflammation, we pretreated mouse bone marrow-derived macrophages (BMDMs) with DAT for 12 hours and then challenged with bacterial lipopolysaccharide (LPS). We found that DAT priming-enhanced type I interferon response while selectively inhibiting proinflammatory interleukin (IL)-6 production after exposure to LPS. This is related to the fact that DAT is a natural antioxidant determined by radical scavenging assay in a cell-free system. DAT-primed cells had increased levels of the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) upon LPS stimulation. Countering the increased NADPH by supplementing extra oxidized NADP+ to cells reversed DAT's effect on LPS-induced Il-6 and interferon-stimulated gene expressions. DAT-primed cells also were more resistant to oxidative stress-induced generation of reactive oxygen species and cell death. DAT promoted the production of antimicrobial effector nitric oxide in a cellular redox-dependent manner, leading to enhanced macrophage antimicrobial activity during Salmonella enterica infection. Our data suggest that DAT acts as a host-microbiota crosstalk signal in shaping host immune defense and inflammatory response.

Association of lifestyle with valvular heart disease progression and life expectancy among elderly people from different socioeconomic backgrounds.

BACKGROUND: Current cardiovascular prevention strategies are based on studies that seldom include valvular heart disease (VHD). The role of modifiable lifestyle factors on VHD progression and life expectancy among the elderly with different socioeconomic statuses (SES) remains unknown. METHODS: This cohort study included 164,775 UK Biobank participants aged 60 years and older. Lifestyle was determined using a five-factor scoring system covering smoking status, obesity, physical activity, diet, and sleep patterns. Based on this score, participants were then classified into "poor," "moderate," or "ideal" lifestyle groups. SES was classified as high or low based on the Townsend Deprivation Index. The association of lifestyle with major VHD progression was evaluated using a multistate mode. The life table method was employed to determine life expectancy with VHD and without VHD. RESULTS: The UK Biobank documented 5132 incident VHD cases with a mean follow-up of 12.3 years and 1418 deaths following VHD with a mean follow-up of 6.0 years. Compared to those with a poor lifestyle, women and men followed an ideal lifestyle had lower hazard ratios for incident VHD (0.66 with 95% CI, 0.59-0.73 for women and 0.77 with 95% CI, 0.71-0.83 for men) and for post-VHD mortality (0.58 for women, 95% CI 0.46-0.74 and 0.62 for men, 95% CI 0.54-0.73). When lifestyle and SES were combined, the lower risk of incident VHD and mortality were observed among participants with an ideal lifestyle and high SES compared to participants with an unhealthy lifestyle and low SES. There was no significant interaction between lifestyle and SES in their correlation with the incidence and subsequent mortality of VHD. Among low SES populations, 60-year-old women and men with VHD who followed ideal lifestyles lived 4.2 years (95% CI, 3.8-4.7) and 5.1 years (95% CI, 4.5-5.6) longer, respectively, compared to those with poor lifestyles. In contrast, the life expectancy gain for those without VHD was 4.4 years (95% CI, 4.0-4.8) for women and 5.3 years (95% CI, 4.8-5.7) for men when adhering to an ideal lifestyle versus a poor one. CONCLUSIONS: Adopting a healthier lifestyle can significantly slow down the progression from free of VHD to incident VHD and further to death and increase life expectancy for both individuals with and without VHD within diverse socioeconomic elderly populations.

Dietary ingredient change induces a transient MyD88-dependent mucosal enteric glial cell response and promotes obesity.

OBJECTIVE: Consumption of a modern Western-type high-fat low-fiber diet increases the risk of obesity. However, how a host responds to such a diet, especially during the early period of dietary transition from a previous low-fat and fiber-rich diet, remains poorly explored. METHODS: Wild-type C57BL/6 mice were fed a normal chow diet or a high-fat diet. Enteric glial cell (EGC) activation was detected through quantitative real-time PCR (qRT-PCR), immunoblotting and immunohistology analysis. Fluorocitrate or genetic deletion of glial fibrillary acidic protein (GFAP)-positive glial-intrinsic myeloid differentiation factor 88 (Myd88) was used to inhibit EGC activation, and the effect of a high-fat diet on obesity was further investigated. The role of MYD88-dependent sensing of commensal products in adipocyte was observed to analyze the effect of obesity. RESULTS: A dietary shift from a normal chow diet to a high-fat diet in mice induced a transient early-phase emergence of a GFAP-positive EGC network in the lamina propria of the ileum, accompanied with an increase in glial-derived neurotrophic factor production. Inhibition of glial cell activity blocked this response. GFAP-positive glial Myd88 knockout mice gained less body weight after high-fat diet (HFD) feeding than littermate controls. In contrast, adipocyte deletion of Myd88 in mice had no effect on weight gain but instead exacerbated glucose intolerance. Furthermore, short-term fluorocitrate intervention during HFD feeding attenuated body weight gain. CONCLUSIONS: Our findings indicate that EGCs are early responders to intestinal ecosystem changes and the GFAP-positive glial Myd88 signaling participates in regulating obesity.

Characterization of an EPS-producing bifidobacterial strain based on integration of phenotypic and complete genome sequencing data.

Bifidobacterium and Lactobacillus are known to be common members of the human intestinal microbiota, which play important roles in maintaining the homeostasis of host gut microenvironment. Several bifidobacterial and lactobacilli strains have been used as probiotics for health benefits. The exopolysaccharides (EPSs) produced by strains from Bifidobacterium and Lactobacillus are considered as beneficial traits mediating these beneficial effects. In this study, 21 strains belonging to Bifidobacterium and Lactobacillus were isolated from healthy infants' stool and were screened for EPS-producing ability. Among these strains, Bifidobacterium longum XZM1 showed the highest EPS productivity, which was further confirmed and characterized. The complete genome of strain XZM1 was sequenced, which revealed the presence of a gene cluster for EPS production. Furthermore, comparative genome analysis was performed among XZM1 and other strains from B. longum species. Following purification, the molecular weight (Mw) of EPS from XZM1 was determined as 4023 Da (Mw) through gel permeation chromatography. Analysis of the EPS hydrolysates revealed that the EPS was composed of mannose, glucose, galactose, arabinose, and fucose. Additionally, the EPS exhibited higher scavenging abilities toward hydroxyl than 1,1-diphenyl-2-picrylhydrazyl free radical. Overall, these results suggest that XZM1 from B. longum species may be a promising probiotic candidate.

A Murine Commensal Protozoan Influences Host Glucose Homeostasis by Facilitating Free Choline Generation.

Recent progress indicates that the gut microbiota plays important role in regulating the host's glucose homeostasis. However, the mechanisms remain unclear. Here, we reported that one integral member of the murine gut microbiota, the protozoan Tritrichomonas musculis could drive the host's glucose metabolic imbalance. Using metabolomics analysis and in vivo assays, we found that mechanistically this protozoan influences the host glucose metabolism by facilitating the production of a significant amount of free choline. Free choline could be converted sequentially by choline-utilizing bacteria and then the host to a final product trimethylamine N-oxide, which promoted hepatic gluconeogenesis. Together, our data reveal a previously underappreciated gut eukaryotic microorganism by working together with other members of microbiota to influence the host's metabolism. Our study underscores the importance and prevalence of metabolic interactions between the gut microbiota and the host in modulating the host's metabolic health. IMPORTANCE Blood glucose levels are important for human health and can be influenced by gut microbes. However, its mechanism of action was previously unknown. In this study, researchers identify a unique member of the gut microbes in mice that can influence glucose metabolism by promoting the host's ability to synthesis glucose by using nonglucose materials. This is because of its ability to generate the essential nutrient choline, and choline, aided by other gut bacteria and the host, is converted to trimethylamine N-oxide, which promotes glucose production. These studies show how gut microbes promote metabolic dysfunction and suggest novel approaches for treating patients with blood glucose abnormality.

Remimazolam versus propofol for deep sedation/anaesthesia in upper gastrointestinal endoscopy in elderly patients: A multicenter, randomized controlled trial.

BACKGROUND AND OBJECTIVE: Propofol is the most commonly used sedative in gastrointestinal endoscopic procedures, but is associated with cardiorespiratory suppression, particularly in elderly patients. Remimazolam is a new short-acting GABA(A) receptor agonist with minimal impact on cardiorespiratory suppression, and may be a viable alternative in elderly patients undergoing endoscopic procedures. METHODS: This multicenter, randomized controlled trial was conducted between September 2020 and September 2021. Elderly patients (65-85 years of age) scheduled to undergo upper gastrointestinal endoscopy were randomized in 1:1 ratio to receive remimazolam tosilate (300 mg/h) or propofol (3 g/h) in addition to 50-µg fentanyl, until the Modified Observer's Assessment of Alertness/Sedation Scale (MOAA/S) reached ≤1. MOAA/S was maintained at 0 or 1 throughout the procedure using 2.5 mg remimazolam or 0.5 mg/kg propofol boluses in the two groups, respectively. The primary outcome was the rate of hypotension (defined as systolic blood pressure at ≤90 mmHg or > 30% decline vs. the baseline). Bradycardia was defined as heart rate ≤50 per minute; respiratory depression was defined as respiratory rate <8 per minute and/or SpO2 < 90%. RESULTS: A total of 400 patients (161 men and 239 women; 70.4 ± 4.6 years of age) were enrolled (200 patients per group). Average body mass index was 22.2 ± 2.4 kg/m2 . The rate of hypotension was 36.5% in the remimazolam group and 69.6% in the propofol group (p < 0.001). The remimazolam group also had a lower rate of bradycardia (1.5% vs. 8.5%, p < 0.001), respiratory depression (4.5% vs. 10.0%, p < 0.05) and pain at the injection site (0% vs. 12.0%, p < 0.001). CONCLUSION: Remimazolam was associated with a lower rate of hypotension in elderly patients undergoing upper gastrointestinal endoscopy under deep sedation/anaesthesia than propofol.

LIGHT (TNFSF14) inhibits glucose uptake of adipocytes by downregulating GLUT4 expression via AKT signaling pathway.

Glucose homeostasis of adipocytes could be regulated by immune-adipose crosstalk. In order to investigate the effects of Lymphotoxin-like inducible protein that competes with glycoprotein D for herpesvirus entry on T cells (LIGHT) on glucose metabolism, we performed the present study. Our results showed that LIGHT deficiency improved glucose tolerance and enhanced glucose consumption of inguinal white adipose tissue (iWAT) under high fat diet. Consistently, Light overexpression could inhibit glucose uptake during the process of white adipogenesis. Mechanistically, LIGHT interacted with lymphotoxin-ß receptor (LTßR) to attenuate AKT pathway leading to downregulation of glucose transporter-4 (GLUT4) expression, which resulted in glucose uptake inhibition. In summary, our findings revealed LIGHT-LTßR-AKT-GLUT4 axis as a regulator of glucose uptake in adipose tissue, which suggested the pivotal role of LIGHT in maintaining glucose homeostasis.

The intestinal microbial metabolite desaminotyrosine is an anti-inflammatory molecule that modulates local and systemic immune homeostasis.

It is considered that intestinal barrier dysfunction and systemic endotoxemia drive obesity and its related complications. However, what causes barrier dysfunction remains to be elucidated. Here, we showed that the gut microbiota from high-fat diet (HFD)-fed mice had impaired ability to degrade dietary flavonoids, and in correspondence, the microbial-derived flavonoid metabolite desaminotyrosine (DAT) was reduced. Supplementation of DAT in the drinking water was able to counter the HFD-induced body fat mass accumulation and body weight increment. This is correlated with the role of DAT in maintaining mucosal immune homeostasis to protect barrier integrity. DAT could attenuate dextran sodium sulfate (DSS)-induced mucosal inflammation in a type I interferon signal-dependent manner. Furthermore, intraperitoneal injection of DAT-protected mice from bacterial endotoxin-induced septic shock. Together, we identified DAT as a gut microbiota-derived anti-inflammatory metabolite that functions to modulate local and systemic immune homeostasis. Our data support the notion of dysbiosis being an important driving force of mucosal barrier dysfunction and systemic metabolic complications.

Commensal Bacteria Impact a Protozoan's Integration into the Murine Gut Microbiota in a Dietary Nutrient-Dependent Manner.

Our current understanding of the host-microbiota interaction in the gut is dominated by studies focused primarily on prokaryotic bacterial communities. However, there is an underappreciated symbiotic eukaryotic protistic community that is an integral part of mammalian microbiota. How commensal protozoan bacteria might interact to form a stable microbial community remains poorly understood. Here, we describe a murine protistic commensal, phylogenetically assigned as Tritrichomonas musculis, whose colonization in the gut resulted in a reduction of gut bacterial abundance and diversity in wild-type C57BL/6 mice. Meanwhile, dietary nutrient and commensal bacteria also influenced the protozoan's intestinal colonization and stability. While mice fed a normal chow diet had abundant T. musculis organisms, switching to a Western-type high-fat diet led to the diminishment of the protozoan from the gut. Supplementation of inulin as a dietary fiber to the high-fat diet partially restored the protozoan's colonization. In addition, a cocktail of broad-spectrum antibiotics rendered permissive engraftment of T. musculis even under a high-fat, low-fiber diet. Furthermore, oral administration of Bifidobacterium spp. together with dietary supplementation of inulin in the high-fat diet impacted the protozoan's intestinal engraftment in a bifidobacterial species-dependent manner. Overall, our study described an example of dietary-nutrient-dependent murine commensal protozoan-bacterium cross talk as an important modulator of the host intestinal microbiome.IMPORTANCE Like commensal bacteria, commensal protozoa are an integral part of the vertebrate intestinal microbiome. How protozoa integrate into a commensal bacterium-enriched ecosystem remains poorly studied. Here, using the murine commensal Tritrichomonas musculis as a proof of concept, we studied potential factors involved in shaping the intestinal protozoal-bacterial community. Understanding the rules by which microbes form a multispecies community is crucial to prevent or correct microbial community dysfunctions in order to promote the host's health or to treat diseases.

LIGHT/TNFSF14 signaling attenuates beige fat biogenesis.

The physiologic signals that regulate beige adipogenesis remain incompletely understood, especially those that limit browning and prevent overexpenditure of energy. In this study, the TNF family member cytokine lymphotoxin-like inducible protein that competes with glycoprotein D for herpesvirus entry on T cells (LIGHT), also known as TNF super family protein 14 (TNFSF14), can inhibit adipose precursor differentiation into beige adipocytes. In acute cold stress, LIGHT deficiency in mice accelerated browning in the subcutaneous white adipose tissue (scWAT). Further experiments showed that LIGHT interacting with lymphotoxin-ß receptor (LTßR) on adipose precursors blocked beige fat biogenesis. LTßR signals attenuated the JNK pathway, which contributed to their antibeiging effect. Blocking JNK activation using a small molecular inhibitor prevented cold-induced scWAT beiging. Furthermore, LIGHT/LTßR signals acted as an attenuator of white adipogenesis. LIGHT deficiency in mice promoted obesity during high-fat diet feeding. These findings identify the LIGHT axis as a regulator of adipose tissue homeostasis and suggest that LIGHT signaling functions as a mechanism to divert energy in favor of immune activation.-Kou, Y., Liu, Q., Liu, W., Sun, H., Liang, M., Kong, F., Zhang, B., Wei, Y., Liu, Z., Wang, Y. LIGHT/TNFSF14 signaling attenuates beige fat biogenesis.

Design Features for Improving Mobile Health Intervention User Engagement: Systematic Review and Thematic Analysis.

BACKGROUND: Well-designed mobile health (mHealth) interventions support a positive user experience; however, a high rate of disengagement has been reported as a common concern regarding mHealth interventions. To address this issue, it is necessary to summarize the design features that improve user engagement based on research over the past 10 years, during which time the popularity of mHealth interventions has rapidly increased due to the use of smartphones. OBJECTIVE: The aim of this review was to answer the question "Which design features improve user engagement with mHealth interventions?" by summarizing published literature with the purpose of guiding the design of future mHealth interventions. METHODS: This review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist. Databases, namely, PubMed, Web of Science, Cochrane Library, Ovid EMBASE, and Ovid PsycINFO, were searched for English and Chinese language papers published from January 2009 to June 2019. Thematic analysis was undertaken to assess the design features in eligible studies. The Mixed Methods Appraisal Tool was used to assess study quality. RESULTS: A total of 35 articles were included. The investigated mHealth interventions were mainly used in unhealthy lifestyle (n=17) and chronic disease (n=10) prevention programs. Mobile phone apps (n=24) were the most common delivery method. Qualitative (n=22) and mixed methods (n=9) designs were widely represented. We identified the following 7 themes that influenced user engagement: personalization (n=29), reinforcement (n=23), communication (n=20), navigation (n=17), credibility (n=16), message presentation (n=16), and interface aesthetics (n=7). A checklist was developed that contained these 7 design features and 29 corresponding specific implementations derived from the studies. CONCLUSIONS: This systematic review and thematic synthesis identified useful design features that make an mHealth intervention more user friendly. We generated a checklist with evidence-based items to enable developers to use our findings easily. Future evaluations should use more robust quantitative approaches to elucidate the relationships between design features and user engagement.

Facile Dissolution of Zein Using a Common Solvent Dimethyl Sulfoxide.

The conformation and stability of zein in solution are closely associated with its solvation process and influence the mechanical properties of the related zein-based materials. In this work, a common solvent dimethyl sulfoxide (DMSO) was used to dissolve zein, rather than solvents frequently used such as aqueous ethanol and acetic acid. It was found that DMSO could dissolve zein readily and the solution was stable for at least 2 weeks. Rheological analysis and small-angle X-ray scattering (SAXS) were employed to characterize the zein DMSO solution. Results of rheological analysis suggested a Huggins coefficient of 0.24, indicating DMSO to be a good solvent for zein. SAXS results revealed that zein adopted an elongated conformation and had dimensions of 2.8 nm × 2.8 nm × 14.8 nm in DMSO solution. Moreover, robust zein films were fabricated from zein DMSO solutions. The content of residual DMSO in the films was determined to be approximately 15 wt % by thermogravimetric analysis, in consistence with the value obtained by other two methods. The film showed a large breaking strain of 320.6% with a considerable breaking stress of 1.9 MPa, yielding a breaking energy of 376.2 MJ/m3. Therefore, the ease of dissolution and good mechanical performance of the final zein-based material make DMSO a potential solvent for fabrication of zein materials, thereby improving the scope of practical applications of zein.

Adaptational changes in physiological and transcriptional responses of Bifidobacterium longum involved in acid stress resistance after successive batch cultures.

Bifidobacterium inhabiting the human and animal intestinal tract is known for its health-promoting effect. Tolerance to acid stress is crucial for bifidobacteria to survive and then exert their beneficial effects in the gut. A long-term adaptation in successive batch cultures was used as evolutionary engineering strategy to improve acid stress tolerance in an industrial probiotic strain, B. longum JDM301. Its derivative, JDM301AR showed higher resistance to several stress conditions, including acid stress than the parental strain, JDM301. To better understand bifidobacterial acid stress response, the changes of fatty acid (FA) in cell membrane of these two strains were determined. A shift in the production of FA in cell membrane, characterized by increased C14:0 was found, when JDM301AR was exposed to low-pH environment. It was implied that the increased production of C14:0 is associated with the acquisition of acid-tolerant phenotype for JDM301AR. High-throughput RNA-sequencing was performed to analyze the changes of gene expression profile after acid-exposure. The transcriptional profiles of JDM301AR and JDM301 under normal condition and acid stress were compared to reveal the different acid response between them. A total of 5 genes involved in FA metabolism were upregulated and no downregulated genes were found in response to acid stress in JDM301AR. The up-regulated BLJ_0565 and BLJ_1105 may play important roles in the modification of membrane FA composition of JDM301AR after acid exposure. Overall, these results suggested that successive batch cultures induced the acid stress tolerance of B. longum involved in transcriptional and physiological responses, including modification of cell wall and cell membrane, metabolism of amino acid and neutralization of internal pH by strengthening NH3 production and transport.

Prevalence, genotype and antimicrobial resistance of Clostridium difficile isolates from healthy pets in Eastern China.

BACKGROUND: Clostridium difficile (C. difficile) is a main cause of antibiotic-associated diarrhoea in humans. Several studies have been performed to reveal the prevalence rate of C. difficile in cats and dogs. However, little is known about the epidemiology of C. difficile in healthy pets in China. This study aimed to assess the burden of C. difficile shedding by healthy dogs and cats in China. Furthermore, the genetic diversity and antimicrobial susceptibility patterns of the recovered isolates were determined. METHODS: A total of 175 faecal samples were collected from 146 healthy dogs and 29 cats. C. difficile strains were isolated and identified from the feces of these pets. The characterized C. difficile strains were typed by multilocus sequence typing (MLST), and the MICs of the isolates were determined against ampicillin, clindamycin, tetracycline, moxifloxacin, chloramphenicol, cefoxitin, metronidazole and vancomycin by the agar dilution method. RESULTS: Overall, 3 faecal samples (1.7%) were C. difficile culture positive. One sample (0.7%) from a dog was C. difficile culture positive, while two cats (7.0%) yielded positive cultures. The prevalence rate differed significantly between cats and dogs. These isolates were typed into 3 MLST genotypes and were susceptible to chloramphenicol, tetracycline, metronidazole and moxifloxacin and resistant to ampicillin, clindamycin and cefoxitin. Notably, one strain, D141-1, which was resistant to three kinds of antibiotics and carried toxin genes, was recovered in the faeces of a healthy dog. CONCLUSION: Our results suggest that common pets may be a source of pathogenic C. difficile, indicating that household transmission of C. difficile from pets to humans can not be excluded.

Physical and Functional Interplay between MazF1Bif and Its Noncognate Antitoxins from Bifidobacterium longum.

Bifidobacterium longum strain JDM301, a widely used commercial strain in China, encodes at least two MazEF-like modules and one RelBE-like toxin-antitoxin (TA) system in its chromosome, designated MazE1F1Bif, MazE2F2Bif, and RelBEBif, respectively. Bacterial TA systems play an important role in several stress responses, but the relationship between these TA systems is largely unknown. In this study, the interactions between MazF1Bif and MazE2Bif or RelBBif were assessed in B. longum strain JDM301. MazF1Bif caused the degradation of tufABif mRNA, and its toxicity was inhibited by forming a protein complex with its cognate antitoxin, MazE1Bif Notably, MazF1Bif toxicity was also partially neutralized when jointly expressed with noncognate antitoxin MazE2Bif or RelBBif Our results show that the two noncognate antitoxins also inhibited mRNA degradation caused by MazF1Bif toxin. Furthermore, the physical interplay between MazF1Bif and its noncognate antitoxins was confirmed by immunoprecipitation. These results suggest that MazF1Bif can arrest cell growth and that MazF1Bif toxicity can be neutralized by its cognate and noncognate antitoxins. These results imply that JDM301 uses a sophisticated toxin-antitoxin interaction network to alter its physiology when coping with environmental stress.IMPORTANCE Although toxin-antitoxin (TA) systems play an important role in several stress responses, the regulatory mechanisms of multiple TA system homologs in the bacterial genome remain largely unclear. In this study, the relationships between MazE1F1Bif and the other two TA systems of Bifidobacterium longum strain JDM301 were explored, and the interactions between MazF1Bif and MazE2Bif or RelBBif were characterized. In addition, the mRNA degradation activity of MazF1Bif was demonstrated. In particular, the interaction of the toxin with noncognate antitoxins was shown, even between different TA families (MazF1Bif toxin and RelBBif antitoxin) in JDM301. This work provides insight into the regulatory mechanisms of TA systems implicated in the stress responses of bifidobacteria.

Functional characterization of RelBE toxin-antitoxin system in probiotic Bifidobacterium longum JDM301.

Toxin-antitoxin (TA) systems are widespread in bacteria and archaea. However, the roles of chromosomally encoded TA systems in bacterial physiology are still open to debate. In this study, a TA module-relBE in Bifidobacterium longum JDM301 (relBE(Bif)) was identified and its function in stress response was evaluated. Bioinformatics analysis of the whole genome sequences of JDM301 revealed a pair of linked genes encoding a RelBE-like TA system (RelBE(Bif)). Our results revealed a bicistronic operon formed by relBE(Bif) in JDM301. Over-expression of RelE(Bif) had a toxic effect on Escherichia coli, which could be neutralized by co-expression of its cognate antitoxin, RelB(Bif) Our data also demonstrated that RelE(Bif) is an mRNA interferase and that the activity of RelE(Bif) can be inhibited by RelB(Bif) These results suggest that RelE(Bif) is a toxic nuclease which arrests cell growth through mRNA degradation, and that the activity of RelE(Bif) can be abolished by co-expression of RelB(Bif) In addition, we also found that the expression of RelBE(Bif) is increased during osmotic stress, suggesting that RelBE(Bif) is activated under this adverse condition. Our results imply that the RelBE(Bif) TA module may represent a cell growth modulator which helps B. longum to deal with osmotic stress.

Improved calculation method for dry modal analysis of four-stage centrifugal-pump rotor system based on concentrated-mass method.

To improve the accuracy of modal analysis for a four-stage centrifugal-pump rotor system with a balancing disc based on the concentrated-mass analytical method, a simplified concentrated mass mathematical model and an ANSYS simulation model are established. The results from these two models are compared to determine factors that cause significant differences in the mode shapes. Subsequently, an optimized mathematical model based on the corrected mass moment of an inertia matrix and stiffness correction coefficients is proposed, and the effectiveness of this optimized mathematical model is validated using a four-stage centrifugal pump with back blades. The results show that the natural frequencies obtained from the ANSYS simulations are consistently higher than those obtained using the analytical method. The simplification of the moment of inertia at the impeller and balancing disc contributes primarily to the calculated errors. The optimized mathematical model reduces the errors in the natural frequencies from 12.96%, 12.13%, 9.96%, 5.85%, and 8.74% to 2.45%, 1.56%, 0.65%, 5.34%, and 2.28%, respectively. The optimization of natural frequencies offers better performance at lower-order modes, whereas its effects on higher-order modes are less significant. The optimization method is applicable to centrifugal pumps with back blades and reduces the error in theoretical calculations, based on reductions in the concentrated mass from 13.11%, 12.85%, 9.91%, and 7.2% to 3.7%, 3.86%, 0.57%, and 2.87%, respectively, thus further confirming the feasibility of the optimized model design.

Assembly of protein-directed fluorescent gold nanoclusters for high-sensitivity detection of uranyl ions.

Uranium is a key element in the nuclear industry, whose accidental release causes health and environmental problems. In this paper, a protein-directed fluorescent sensor with aggregation-induced emission characteristics (gold nanoclusters@ovalbumin, AuNCs@OVA) was synthesized for the detection of UO22+ with high sensitivity and selectivity. The sensor exhibited good fluorescence stability, and its fluorescence intensity could be selectively enhanced by UO22+. Based on FT-IR and XPS analyses, the increase in fluorescence intensity of AuNCs@OVA after the addition of UO22+ was attributed to aggregation induced by the complexation between UO22+ and the amino, carboxyl, hydroxyl, and phosphate groups of ovalbumin. The detection limit was determined to be 34.4 nM, and the sensor showed excellent ion selectivity for UO22+. In combination with a smartphone program, the sensor could realize the real-time detection of UO22+ in a quantitative and portable way.

Sulfonated cottonseed hydrolysates with adjustable amphiphilicity as environmental -Stress stable emulsifiers.

Cottonseed protein isolate (CPI) is a valuable agro-industrial waste with potential biotechnological applications. However, inadequate stability in water due to its characteristic hinders its widespread use. Therefore, a new sulfonation modification approach was developed to improve the amphiphilicity and structural flexibility of CPI. Structural characterizations confirmed the successful incorporation of sulfonate groups with structural and conformational changes. This significantly unfolded molecular-chain, and improved amphiphilicity, flexibility, and surface-hydrophobicity while reducing pI (5.1-1.7), and molecular-weight (5745-2089 g/mol). The modified samples exhibited improved emulsification with higher amounts of absorbed proteins on the droplet interface, smaller droplet size, and a higher zeta-potential. Additionally, they possessed good emulsification ability under acidic conditions. The nano-emulsions exhibited long-term stability (≥70 days) under different environmental conditions, with excellent fluidity. This study contributes to understanding sulfonation as a viable approach for improving protein properties, thus, opening up new possibilities for their application and maximizing their economic benefits.

Microbial succession in different years of pit mud from a distillery in Sichuan for Nong-xiang Baijiu fermentation.

Microbial community and succession of 5-, 20-, and 50-year pit mud (PM) were uncovered in this study. The results showed that Bacteroidetes, Firmicutes and Ascomycota were dominant phyla in these PM samples. Interestingly, most sequences could not be classified into fungal taxa at the genus level by UNITE Database, the diversity and richness of bacteria in these PMs were higher than that of fungi. It was noteworthy that both 20-year and 50-year PMs exhibited higher abundances of Caproiciproducens and Petrimonas when compared with 5-year PM. While higher proportions of Lactobacillus and Acinetobacter were observed in the 5-year PM. Furfermore, these PMs microbiota mainly involved biosynthesis, degradation, and generation of precursor metabolites, which contributed to carbon cycling of Nong-xiang Baijiu anaerobic fermentation. Taken together, lactic acid bacteria depletion and caproic acid bacteria accumulation might be an important succession trend of PM microbiota during the long-term fermentation of Chinese Nong-xiang Baijiu. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-024-01558-4.