Zinc-doped C4N3/BiOBr S-scheme heterostructured hollow spheres for efficient photocatalytic degradation of tetracycline.

Photocatalytic degradation of organic pollutants in water is of great significance to the sustainable development of the environment, but encounters limited efficiency when a single compound is used. Thus, there have been enormous efforts to find novel photocatalytic heterostructured composites with high performance. In this work, a novel S-scheme heterostructure is constructed with BiOBr and Zn2+ doped C4N3 (Zn-C4N3) by a solvothermal method for efficient photodegradation of tetracycline (TC), a residual antibiotic difficult to be removed from the aquatic environment. Thanks to Zn2+-doping induced improvement in chemical affinity between Zn-C4N3 and BiOBr, well-formed Zn-C4N3/BiOBr heterostructured hollow spheres are formed. This structure can efficiently suppress fast recombination of photogenerated electron-hole pairs to enhance the photocatalytic activity of BiOBr dramatically. At a room temperature of 25 °C and neutral pH 7, the catalyst can degrade a significant portion of TC pollutants within 30 min under visible light. Also, the Zn-C4N3/BiOBr heterostructure displays good stability after recycling experiments. Free radical capture experiments and ESR tests show that ˙O2- is the main active substance for photocatalytic degradation of TC. This study provides new insights for constructing heterostructures with an intimate interface between the two phases for photocatalytic applications.

Crystalline Phase Regulates Microbial Methylation Potential of Mercury Bound to MoS2 Nanosheets: Implications for Safe Design of Mercury Removal Materials.

Transition-metal dichalcogenides (TMDs) have shown great promise as selective and high-capacity sorbents for Hg(II) removal from water. Yet, their design should consider safe disposal of spent materials, particularly the subsequent formation of methylmercury (MeHg), a highly potent and bioaccumulative neurotoxin. Here, we show that microbial methylation of mercury bound to MoS2 nanosheets (a representative TMD material) is significant under anoxic conditions commonly encountered in landfills. Notably, the methylation potential is highly dependent on the phase compositions of MoS2. MeHg production was higher for 1T MoS2, as mercury bound to this phase primarily exists as surface complexes that are available for ligand exchange. In comparison, mercury on 2H MoS2 occurs largely in the form of precipitates, particularly monovalent mercury minerals (e.g., Hg2MoO4 and Hg2SO4) that are minimally bioavailable. Thus, even though 1T MoS2 is more effective in Hg(II) removal from aqueous solution due to its higher adsorption affinity and reductive ability, it poses a higher risk of MeHg formation after landfill disposal. These findings highlight the critical role of nanoscale surfaces in enriching heavy metals and subsequently regulating their bioavailability and risks and shed light on the safe design of heavy metal sorbent materials through surface structural modulation.

Hook-Like DNAzyme-Activated Autocatalytic Biosensor for the Universal Detection of Pathogenic Bacteria.

DNAzyme-based assays have found extensive utility in pathogenic bacteria detection but often suffer from limited sensitivity and specificity. The integration of a signal amplification strategy could address this challenge, while the existing combination methods require extensive modification to accommodate various DNAzymes, limiting the wide-spectrum bacteria detection. We introduced a novel hook-like DNAzyme-activated autocatalytic nucleic acid circuit for universal pathogenic bacteria detection. The hook-like connector DNA was employed to seamlessly integrate the recognition element DNAzyme with the isothermal enzyme-free autocatalytic hybridization chain reaction and catalytic hairpin assembly for robust exponential signal amplification. This innovative autocatalytic circuit substantially amplifies the output signals from the DNAzyme recognition module, effectively overcoming DNAzyme's inherent sensitivity constraints in pathogen identification. The biosensor exhibits a strong linear response within a range of 1.5 × 103 to 3.7 × 107 CFU/mL, achieving a detection limit of 1.3 × 103 CFU/mL. Noted that the sensor's adaptability as a universal detection platform is established by simply modifying the hook-like connector module, enabling the detection of various pathogenic bacteria of considerable public health importance reported by the World Health Organization, including Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Salmonella typhimurium. Additionally, the specificity of DNAzyme in bacterial detection is markedly improved due to the signal amplification process of the autocatalytic circuit. This hook-like DNAzyme-activated autocatalytic platform presents a versatile, sensitive, and specific approach for pathogenic bacteria detection, promising to significantly expand the applications of DNAzyme in bacteria detection.

COVID-19 vaccination and long COVID among 50 years older and above European: The role of chronic multimorbidity.

BACKGROUND AND AIMS: We aimed to explore the association between coronavirus disease-19 (COVID-19) vaccination and long COVID according to the status of chronic multimobidity. METHODS: A total of 1913 participants were recruited in the cross-sectional study on the basis of the Survey of Health and Retirement in Europe. COVID-19 vaccination was defined as vaccination within the last 12 months. Chronic multimorbidity was defined as history of 2 + chronic disease. The study outcome was long COVID during the 12-month follow-up. Multivariable logistic models were performed to estimate the influence of chronic multimorbidity on the association of vaccination with long COVID. Net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were calculated. RESULTS: Chronic multimorbidity significantly modified the association of COVID-19 vaccination with long COVID (Pinteraction = 0.024). The rates of study outcome were significantly lower among vaccinated participants in the chronic multimorbidity subgroup, but not in the other subgroup. Multivariable odds ratios (95 % confidence intervals) of study outcome for unvaccination vs. vaccination were 1.494 (1.013-2.203) in those with multimorbidity and 0.915 (0.654-1.280) in those without multimorbidity, respectively. Adding COVID-19 vaccination to a model containing conventional risk factors significantly improved risk reclassification for study outcome among those with chronic multimobidity (continuous NRI was 25.39 % [P = 0.002] and IDI was 0.42 % [P = 0.075]) CONCLUSION: An inverse association of COVID-19 vaccination with long COVID was found among participants with chronic multimorbidity, but not among those without chronic multimorbidity. Chronic multimorbidity might expand the influence of unvaccination on developing long COVID among European aged ≥50 years.

Organic-Acid-Sensitive Visual Sensor Array Based on Fenton Reagent-Phenol/Aniline for the Rapid Species and Adulteration Assessment of Baijiu.

Baijiu is an ancient, distilled spirit with a complicated brewing process, unique taste, and rich trace components. These trace components play a decisive role in the aroma, taste, and especially the quality of baijiu. In this paper, the redox reaction between the Fenton reagent and four reducing agents, including o-phenylenediamine (OPD), p-phenylenediamine (PPD), 4-aminophenol (PAP), and 2-aminophenol (OAP), was adopted to construct a four-channel visual sensor array for the rapid detection of nine kinds of common organic acids in baijiu and the identification of baijiu and its adulteration. By exploiting the color-changing fingerprint response brought by organic acids, each organic acid could be analyzed accurately when combined with an optimized variable-weighted least-squares support vector machine based on a particle swarm optimization (PSO-VWLS-SVM) model. What is more, this novel sensor also could achieve accurate semi-quantitative analysis of the mixed organic acid samples via partial least squares discriminant analysis (PLSDA). Most importantly, the sensor array could be further used for the identification of baijiu with different species through the PLSDA model and the adulteration assessment with the one-class partial least squares (OCPLS) model simultaneously.

Single-Atom Iron Can Steer Atomic Hydrogen toward Selective Reductive Dechlorination: Implications for Remediation of Chlorinated Solvents-Impacted Groundwater.

Atomic hydrogen (H*) is a powerful and versatile reductant and has tremendous potential in the degradation of oxidized pollutants (e.g., chlorinated solvents). However, its application for groundwater remediation is hindered by the scavenging side reaction of H2 evolution. Herein, we report that a composite material (Fe0@Fe-N4-C), consisting of zerovalent iron (Fe0) nanoparticles and nitrogen-coordinated single-atom Fe (Fe-N4), can effectively steer H* toward reductive dechlorination of trichloroethylene (TCE), a common groundwater contaminant and primary risk driver at many hazardous waste sites. The Fe-N4 structure strengthens the bond between surface Fe atoms and H*, inhibiting H2 evolution. Nonetheless, H* is available for dechlorination, as the adsorption of TCE weakens this bond. Interestingly, H* also enhances electron delocalization and transfer between adsorbed TCE and surface Fe atoms, increasing the reactivity of adsorbed TCE with H*. Consequently, Fe0@Fe-N4-C exhibits high electron selectivity (up to 86%) toward dechlorination, as well as a high TCE degradation kinetic constant. This material is resilient against water matrix interferences, achieving long-lasting performance for effective TCE removal. These findings shed light on the utilization of H* for the in situ remediation of groundwater contaminated with chlorinated solvents, by rational design of earth-abundant metal-based single-atom catalysts.

Heterogeneous hydrochlorination of lipids mediated by fatty acids in an indoor environment.

Fatty acids from cooking fumes and hypochlorous acid (HOCl) released from indoor cleaning adversely affect respiratory health, but the molecular-level mechanism remains unclear. Here, the effect of cooking oil fumes [palmitic acid (PA), oleic acid (OA), and linoleic acid (LA)] on lung model phospholipid (POPG) hydrochlorination mediated by HOCl at the air-water interface of the hanged droplets was investigated. Interfacial hydrochlorination of POPG was impeded by OA and LA, while that of POPG was facilitated by PA. The effect on POPG hydrochlorination increased with the decrease in oil fume concentration. A potential mechanism with respect to the chain length of these oil fumes, regardless of their saturation, was proposed. PA with a short carbon chain looses the POPG packing and leads to the exposure of the C=C double bonds of POPG, whereas OA and LA with a long carbon chain hinder HOCl from reaching the C=C bonds of POPG. These results for short chain and low concentration dependence suggest that the decay of oil fumes or the conversion of short-chain species by indoor interfacial chemistry might be adverse to lung health. These results provide insights into the relationship between indoor multicomponent pollutants and the respiratory system.

TNF-α/TNFR1 activated astrocytes exacerbate depression-like behavior in CUMS mice.

Neuroinflammation is considered to be a significant mechanism contributing to depression. Several studies have reported that A1 astrocytes were highly prevalent in human neuroinflammatory and neurodegenerative diseases. However, the precise mechanism by which A1 astrocytes contribute to depression remains unclear. Clinical studies have suggested a correlation between TNF-α, an activator of A1 astrocytes, and the severity of depression. Based on these findings, we hypothesized that TNF-α might worsen depression by activating A1 astrocytes. Our previous studies indicated that Rhodomyrtone (Rho) has the potential to improve depression-like behavior in mice. However, the exact mechanism for this effect has not been fully elucidated. Importantly, it was reported that Rho alleviated skin inflammation in a mouse model of psoriasis by inhibiting the expression of TNF-α. Based on this finding, we hypothesized that rhodomyrtone may exert antidepressant effects by modulating the TNF-α pathway. However, further research is required to investigate and validate these hypotheses, shedding light on the relationships between neuroinflammation, A1 astrocytes, TNF-α, and depression. By obtaining a deeper understanding of the underlying mechanisms, these findings could lead to the development of novel antidepressant strategies that target the TNF-α pathway in the context of neuroinflammation. In vivo, based on the established chronic unpredictable mild stress (CUMS) mouse depression model, we characterized the mechanism of TNF-α and Rho during depression by using several behavioral assays, adeno-associated virus(AAV) transfection, western blotting, immunofluorescence, and other experimental methods. In vitro, we characterized the effect of Rho on inflammation in TNF-α-treated primary astrocytes. TNFR1 expression was significantly increased in the hippocampus of depression-like mice, with increased astrocytes activation and neuronal apoptosis. These processes were further enhanced with increasing levels of TNF-α in the cerebrospinal fluid of mice. However, this process was attenuated by knockdown of TNFR1 and infliximab (Inf; a TNF-α antagonist). Injection of rhodomyrtone decreased the expressions of TNFR1 and TNF-α, resulting in significant improvements in mouse depression-like behaviors and reduction of astrocyte activation. TNF-α could be involved in the pathophysiological process of depression, through mediating astrocytes activation by binding to TNFR1. By blocking this pathway, Rho may be a novel antidepressant.

Association of serum metal levels with type 2 diabetes: A prospective cohort and mediating effects of metabolites analysis in Chinese population.

Several studies have suggested an association between exposure to various metals and the onset of type 2 diabetes (T2D). However, the results vary across different studies. We aimed to investigate the associations between serum metal concentrations and the risk of developing T2D among 8734 participants using a prospective cohort study design. We utilized inductively coupled plasmamass spectrometry (ICP-MS) to assess the serum concentrations of 27 metals. Cox regression was applied to calculate the hazard ratios (HRs) for the associations between serum metal concentrations on the risk of developing T2D. Additionally, 196 incident T2D cases and 208 healthy control participants were randomly selected for serum metabolite measurement using an untargeted metabolomics approach to evaluate the mediating role of serum metabolite in the relationship between serum metal concentrations and the risk of developing T2D with a nested casecontrol study design. In the cohort study, after Bonferroni correction, the serum concentrations of zinc (Zn), mercury (Hg), and thallium (Tl) were positively associated with the risk of developing T2D, whereas the serum concentrations of manganese (Mn), molybdenum (Mo), barium (Ba), lutetium (Lu), and lead (Pb) were negatively associated with the risk of developing T2D. After adding these eight metals, the predictive ability increased significantly compared with that of the traditional clinical model (AUC: 0.791 vs. 0.772, P=8.85×10-5). In the nested casecontrol study, a machine learning analysis revealed that the serum concentrations of 14 out of 1579 detected metabolites were associated with the risk of developing T2D. According to generalized linear regression models, 7 of these metabolites were significantly associated with the serum concentrations of the identified metals. The mediation analysis showed that two metabolites (2-methyl-1,2-dihydrophthalazin-1-one and mestranol) mediated 46.81% and 58.70%, respectively, of the association between the serum Pb concentration and the risk of developing T2D. Our study suggested that serum Mn, Zn, Mo, Ba, Lu, Hg, Tl, and Pb were associated with T2D risk. Two metabolites mediated the associations between the serum Pb concentration and the risk of developing T2D.

Liquiritigenin Induces Cell Cycle Arrest and Apoptosis in Lung Squamous Cell Carcinoma.

Liquiritigenin (LQ), as a dihydroflavone monomer compound extracted from Glycyrrhiza uralensis Fisch, has been demonstrated to show anti-tumor effects in multiple human cancers, including lung adenocarcinoma. Our study aimed to explore its role in lung squamous cell carcinoma (LSCC) development and the related mechanism. The effects of LQ on SK-MES-1 and NCI-H520 cell proliferation, cell cycle, and apoptosis were investigated. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and colony formation assays revealed that LQ inhibited LSCC cell viability and proliferation in a dose- and time-dependent manner. Flow cytometry analysis demonstrated that LQ promoted G2/M cell cycle arrest, cell apoptosis, and loss of mitochondrial membrane potential. In vivo assays showed that LQ administration suppressed tumor growth in nude mice. Additionally, LQ treatment reduced the levels of phosphorylated PI3K, AKT, and mTOR levels in LSCC cells. Pretreatment with the PI3K inhibitor LY294002 antagonized the LQ-mediated effects on cell proliferation, cell cycle arrest, and apoptosis in LSCC cells. Collectively, LQ induces cell cycle arrest and apoptosis in LSCC by inactivating the PI3K/AKT/mTOR pathway.

Brassinosteroids biosynthetic gene MdBR6OX2 regulates salt stress tolerance in both apple and Arabidopsis.

Salt stress is a critical limiting factor for fruit yield and quality of apples. Brassinosteroids (BRs) play an important role in response to abiotic stresses. In the present study, application of 2,4- Epicastasterone on seedlings of Malus 'M9T337' and Malus domestica 'Gala3' alleviated the physiological effects, such as growth inhibition and leaf yellowing, induced by salt stress. Further analysis revealed that treatment with NaCl induced expression of genes involved in BR biosynthesis in 'M9T337' and 'Gala3'. Among which, the expression of BR biosynthetic gene MdBR6OX2 showed a three-fold upregulation upon salt treatment, suggesting its potential role in response to salt stress in apple. MdBR6OX2, belonging to the CYP450 family, contains a signal peptide region and a P450 domain. Expression patterns analysis showed that the expression of MdBR6OX2 can be significantly induced by different abiotic stresses. Overexpressing MdBR6OX2 enhanced the tolerance of apple callis to salt stress, and the contents of endogenous BR-related compounds, such as Typhastero (TY), Castasterone (CS) and Brassinolide (BL) were significantly increased in transgenic calli compared with that of wild-type. Extopic expression of MdBR6OX2 enhanced tolerance to salt stress in Arabidopsis. Genes associated with salt stress were significantly up-regulated, and the contents of BR-related compounds were significantly elevated under salt stress. Our data revealed that BR-biosynthetic gene MdBR6OX2 positively regulates salt stress tolerance in both apple calli and Arabidopsis.

Ozonolysis of phospholipids at the air-water interface intervened by polyfluoroalkyl substances.

Perfluoroalkyl substances (PFASs) are ubiquitous in the environment and even accumulate in the human body associated with their excellent stability and persistence. However, the effect and reaction mechanism at the molecular level on the cell phospholipid peroxidation remained unclear. In this work, the interfacial reaction of model phospholipids (POPG) intervened by per- and polyfluoroalkyl substances (PFASs) at the air-water interface of a hanged droplet exposed to ozone (O3) was investigated. Perfluorinated carboxylates and sulfonates were evaluated. Four-carbon PFASs promoted interfacial ozonolysis, but PFASs with longer carbon skeletons impeded this chemistry. A model concerning POPG packing was proposed and it was concluded that the interfacial chemistry was mediated by chain length rather than their functional groups. Four-carbon PFASs could couple into POPG ozonolysis by mainly reacting with aldehyde products along with minor Criegee intermediates, but this was not observed for longer PFASs. This is different from that condensed-phase Criegee intermediates preferred to reacting with per-fluoroalkyl carboxylic acids. These results provide insight into the adverse health of PFASs on cell peroxidation.

Cr(VI) Reduction and Sequestration by FeS Nanoparticles Formed in situ as Aquifer Material Coating to Create a Regenerable Reactive Zone.

Remediation of large and dilute plumes of groundwater contaminated by oxidized pollutants such as chromate is a common and difficult challenge. Herein, we show that in situ formation of FeS nanoparticles (using dissolved Fe(II), S(-II), and natural organic matter as a nucleating template) results in uniform coating of aquifer material to create a regenerable reactive zone that mitigates Cr(VI) migration. Flow-through columns packed with quartz sand are amended first with an Fe2+ solution and then with a HS- solution to form a nano-FeS coating on the sand, which does not hinder permeability. This nano-FeS coating effectively reduces and immobilizes Cr(VI), forming Fe(III)-Cr(III) coprecipitates with negligible detachment from the sand grains. Preconditioning the sand with humic or fulvic acid (used as model natural organic matter (NOM)) further enhances Cr(VI) sequestration, as NOM provides additional binding sites of Fe2+ and mediates both nucleation and growth of FeS nanoparticles, as verified with spectroscopic and microscopic evidence. Reactivity can be easily replenished by repeating the procedures used to form the reactive coating. These findings demonstrate that such enhancement of attenuation capacity can be an effective option to mitigate Cr(VI) plume migration and exposure, particularly when tackling contaminant rebound post source remediation.

Cloning and functional identification of apple LATERAL ORGAN BOUNDARY DOMAIN 3 (LBD3) transcription factor in the regulation of drought and salt stress.

MAIN CONCLUSION: Overexpression of MdLBD3 in Arabidopsis reduced sensitivity to salt and drought stresses and was instrumental in promoting early flowering. Salt and drought stresses have serious effects on plant growth. LATERAL ORGAN BOUNDARY DOMAIN (LBD) proteins are a plant-specific transcription factors (TFs) family and play important roles in plants in resisting to abiotic stress. However, about the function of LBDs in apple and other woody plants is little known. In this study, protein sequences of the LBD family TFs in apples were identified which contained conserved LOB domains. The qRT-PCR analysis showed that the MdLBD3 gene was widely expressed in various tissues and organs. The subcellular localization assay showed that the MdLBD3 protein was localized in the nucleus. Ectopic expression of MdLBD3 in Arabidopsis positively regulated its salt and drought resistance, and promoted early flowering. Collectively, these results showed that MdLBD3 improved the abiotic stress resistance, plant growth and development. Overall, this study provided a new gene for breeding that can increase the abiotic stress tolerance in apple.

Small RNA SmsR1 modulates acidogenicity and cariogenic virulence by affecting protein acetylation in Streptococcus mutans.

Post-transcriptional regulation by small RNAs and post-translational modifications (PTM) such as lysine acetylation play fundamental roles in physiological circuits, offering rapid responses to environmental signals with low energy consumption. Yet, the interplay between these regulatory systems remains underexplored. Here, we unveil the cross-talk between sRNAs and lysine acetylation in Streptococcus mutans, a primary cariogenic pathogen known for its potent acidogenic virulence. Through systematic overexpression of sRNAs in S. mutans, we identified sRNA SmsR1 as a critical player in modulating acidogenicity, a key cariogenic virulence feature in S. mutans. Furthermore, combined with the analysis of predicted target mRNA and transcriptome results, potential target genes were identified and experimentally verified. A direct interaction between SmsR1 and 5'-UTR region of pdhC gene was determined by in vitro binding assays. Importantly, we found that overexpression of SmsR1 reduced the expression of pdhC mRNA and increased the intracellular concentration of acetyl-CoA, resulting in global changes in protein acetylation levels. This was verified by acetyl-proteomics in S. mutans, along with an increase in acetylation level and decreased activity of LDH. Our study unravels a novel regulatory paradigm where sRNA bridges post-transcriptional regulation with post-translational modification, underscoring bacterial adeptness in fine-tuning responses to environmental stress.

Stanniocalcin 2 governs cancer cell adaptation to nutrient insufficiency through alleviation of oxidative stress.

Solid tumours often endure nutrient insufficiency during progression. How tumour cells adapt to temporal and spatial nutrient insufficiency remains unclear. We previously identified STC2 as one of the most upregulated genes in cells exposed to nutrient insufficiency by transcriptome screening, indicating the potential of STC2 in cellular adaptation to nutrient insufficiency. However, the molecular mechanisms underlying STC2 induction by nutrient insufficiency and subsequent adaptation remain elusive. Here, we report that STC2 protein is dramatically increased and secreted into the culture media by Gln-/Glc-deprivation. STC2 promoter contains cis-elements that are activated by ATF4 and p65/RelA, two transcription factors activated by a variety of cellular stress. Biologically, STC2 induction and secretion promote cell survival but attenuate cell proliferation during nutrient insufficiency, thus switching the priority of cancer cells from proliferation to survival. Loss of STC2 impairs tumour growth by inducing both apoptosis and necrosis in mouse xenografts. Mechanistically, under nutrient insufficient conditions, cells have increased levels of reactive oxygen species (ROS), and lack of STC2 further elevates ROS levels that lead to increased apoptosis. RNA-Seq analyses reveal STC2 induction suppresses the expression of monoamine oxidase B (MAOB), a mitochondrial membrane enzyme that produces ROS. Moreover, a negative correlation between STC2 and MAOB levels is also identified in human tumour samples. Importantly, the administration of recombinant STC2 to the culture media effectively suppresses MAOB expression as well as apoptosis, suggesting STC2 functions in an autocrine/paracrine manner. Taken together, our findings indicate that nutrient insufficiency induces STC2 expression, which in turn governs the adaptation of cancer cells to nutrient insufficiency through the maintenance of redox homeostasis, highlighting the potential of STC2 as a therapeutic target for cancer treatment.

KCTD5 regulates Ikaros degradation induced by chemotherapeutic drug etoposide in hematological cells.

Therapy-related leukemia carries a poor prognosis, and leukemia after chemotherapy is a growing risk in clinic, whose mechanism is still not well understood. Ikaros transcription factor is an important regulator in hematopoietic cells development and differentiation. In the absence of Ikaros, lymphoid cell differentiation is blocked at an extremely early stage, and myeloid cell differentiation is also significantly affected. In this work, we showed that chemotherapeutic drug etoposide reduced the protein levels of several isoforms of Ikaros including IK1, IK2 and IK4, but not IK6 or IK7, by accelerating protein degradation, in leukemic cells. To investigate the molecular mechanism of Ikaros degradation induced by etoposide, immunoprecipitation coupled with LC-MS/MS analysis was conducted to identify changes in protein interaction with Ikaros before and after etoposide treatment, which uncovered KCTD5 protein. Our further study demonstrates that KCTD5 is the key stabilizing factor of Ikaros and chemotherapeutic drug etoposide induces Ikaros protein degradation through decreasing the interaction of Ikaros with KCTD5. These results suggest that etoposide may induce leukemic transformation by downregulating Ikaros via KCTD5, and our work may provide insights to attenuate the negative impact of chemotherapy on hematopoiesis.

Electrospun Fiber Membrane with the Dual Affinity of Chelation and Covalent Interactions for the Efficient Enrichment of Glycoproteins.

As important biomarkers of many diseases, glycoproteins are of great significance to biomedical science. It is essential to develop efficient glycoprotein enrichment platforms and investigate their adsorption mechanism. In this work, a conspicuous enrichment strategy for glycoproteins was developed by using an electrospun fiber membrane wrapped with polydopamine (PDA) and modified with 3-aminophenylboronic acid and nickel ions, named PAN/DA@PDA@APBA/Ni. The enrichment characteristics of PAN/DA@PDA@APBA/Ni toward glycoproteins were explored through adsorption behavior. Thanks to the existence of two sites of interaction (metal ion chelation and boronate affinity), PAN/DA@PDA@APBA/Ni exhibited significant enrichment capacity for glycoproteins, ovalbumin (604.6 mg/g), and human immunoglobulin G (331.0 mg/g). The adsorption kinetic results of glycoprotein ovalbumin on PAN/DA@PDA@APBA/Ni conform to the pseudo-first-order kinetic model in the first adsorption stage, while the second half adsorption stage is more in line with the pseudo-second-order kinetic model. Moreover, the physical characteristics of PAN/DA@PDA@APBA/Ni and subsequent adsorption experiments on electrospun fiber modified with only phenylboronic acid or nickel ions both confirmed two sites of interaction (metal ion chelation and boronate affinity, respectively). Furthermore, a stepwise elution method with dual-affinity interaction was designed and successfully applied to enrich glycoproteins in real biological samples. This work provides an idea for sample pretreatment, especially for the design of dual-affinity materials in glycoproteins enrichment.

[Advances in fermentative production of L-tryptophan: a review].

L-tryptophan is an essential amino acid that is widely used in food, medicine and feed sectors. L-tryptophan can be produced through fermentation, and the main producing strains are engineered Escherichia coli and Corynebacterium glutamicum, which are constructed by rational design methods based on metabolic engineering and synthetic biology. However, due to the long metabolic pathway, complex and unclear regulatory mechanism for L-tryptophan production in microbial cells, the production efficiency and robustness of L-tryptophan producing strains are still low. In this connection, irrational design methods such as laboratory adaptive evolution, are often applied to improve the performance of L-tryptophan producing strains. This review summarizes the recent progress on biosynthesis metabolism of L-tryptophan and its regulation, the construction and optimization of L-tryptophan producing strains, and fermentative production of L-tryptophan, and prospects future development perspective. This review may facilitate research and development for fermentative production of L-tryptophan.

[Whole-cell catalytic production of pseudouridine by recombinant Escherichia coli].

Pseudouridine is the most abundant modified nucleoside found in non-coding RNA and is widely used in biological and pharmaceutical fields. However, current methods for pseudouridine production suffer from drawbacks such as complex procedures, low efficiency and high costs. This study presents a novel enzymatic cascade reaction route in Escherichia coli, enabling the whole-cell catalytic synthesis of pseudouridine from uridine. Initially, a metabolic pathway was established through plasmid-mediated overexpression of endogenous pseudouridine-5-phosphase glycosidase, ribokinase, and ribonucleoside hydrolase, resulting in the accumulation of pseudouridine. Subsequently, highly active endogenous ribonucleoside hydrolase was screened to enhance uridine hydrolysis and provide more precursors for pseudouridine synthesis. Furthermore, modifications were made to the substrates and products transport pathways to increase the pseudouridine yield while avoiding the accumulation of by-product uridine. The resulting recombinant strain Ψ-7 catalyzed the conversion of 30 g/L uridine into 27.24 g/L pseudouridine in 24 h, achieving a conversion rate of 90.8% and a production efficiency of 1.135 g/(L·h). These values represent the highest reported yield and production efficiency achieved by enzymatic catalysis methods to date.