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Abstract The widespread use of polymers has made our lives increasingly convenient by offering a more convenient and dependable material. However, the challenge of efficiently decomposing these materials has resulted in a surge of polymer waste, posing environment and health risk. Currently, landfill and incineration treatment approaches have notable shortcomings, prompting a shift towards more eco-friendly and sustainable biodegradation approaches. Biodegradation primarily relies on microorganisms, with research focusing on both solitary bacterial strain and multi-strain communities for polymer biodegradation. Furthermore, directed evolution and rational design of enzyme have significantly contributed to the polymer biodegradation process. However, previous reviews often undervaluing the role of multi-strain communities. In this review, we assess the current state of these three significant fields of research, provide practical solutions to issues with polymer biodegradation, and outline potential future directions for the subject. Ultimately, biodegradation, whether facilitated by single bacteria, multi-strain communities, or engineered enzymes, now represents the most effective method for managing waste polymers. Graphical Abstract

Abstract Hydroxylated aromatic compounds exhibit exceptional biological activities. In the biosynthesis of these compounds, three types of hydroxylases are commonly employed: cytochrome P450 (CYP450), pterin-dependent monooxygenase (PDM), and flavin-dependent monooxygenase (FDM). Among these, FDM is a preferred choice due to its small molecular weight, stable expression in both prokaryotic and eukaryotic fermentation systems, and a relatively high concentration of necessary cofactors. However, the catalytic efficiency of many FDMs falls short of meeting the demands of large-scale production. Additionally, challenges arise from the limited availability of cofactors and compatibility issues among enzyme components. Recently, significant progress has been achieved in improving its catalytic efficiency, but have not yet detailed and informative viewed so far. Therefore, this review emphasizes the advancements in FDMs for the biosynthesis of hydroxylated aromatic compounds and presents a summary of three strategies aimed at enhancing their catalytic efficiency: (a) Developing efficient enzyme mutants through protein engineering; (b) enhancing the supply and rapid circulation of critical cofactors; (c) facilitating cofactors delivery for enhancing FDMs catalytic efficiency. Furthermore, the current challenges and further perspectives on improving catalytic efficiency of FDMs are also discussed.

ABSTRACTOrganic selenium has been widely studied for its ability to better fulfill the physiological functions of selenium. In this study, a novel organic selenium (wheat protein hydrolyzate chelated selenium, WPH-Se) was prepared by chelating the hydrolyzate of wheat protein hydrolyzed by alkaline protease (WPH) with selenium, its preparation process was optimized; and structural and functional properties were investigated. The results showed that the highest selenium content of 10.97 mg/g was obtained in the chelate under the optimal conditions (peptide/selenium mass ratio 2:1, temperature 80°C, pH 8, time 60 min). UV-Vis, FTIR, DSC and SEM provided more information for the characterization of WPH-Se. During the chelating process, selenium ions might be effectively bound to WPH through carboxyl, carbonyl and amino ligands, and the C=O bond and -NH, -OH groups might be the sites. At different pHs, the solubility of WPH-Se was generally lower than that of WPH, which reached a maximum of 32.69% at pH 6. The EAI of WPH-Se was higher than that of WPH, which reached a maximum of 0.84 m2/g, and the ESI reached a maximum of 47.3 min at pH 10. The free sulfhydryl content of WPH-Se was greater than that of WPH, which reached a maximum of 12.78 μmol/g at pH 8. WPH-Se was superior to WPH in terms of foaming ability and emulsification properties. WPH-Se contained a certain amount of aromatic amino acids (7.962%) and a relatively high amount of hydrophobic amino acids (38.490%), and had high nutritional value. Wheat protein peptide chelated selenium would be a useful functional additive, this study would provide data to support further research and application of selenium dietary supplements.

Abstract Background Lignocellulose, the most abundant non-edible feedstock on Earth, holds substantial potential for eco-friendly chemicals, fuels, and pharmaceuticals production. Glucose, xylose, and arabinose are primary components in lignocellulose, and their efficient conversion into high-value products is vital for economic viability. While glucose and xylose have been explored for such purpose, arabinose has been relatively overlooked. Results This study demonstrates a microbial platform for producing 1,2,4-butanetriol (BTO) from arabinose, a versatile compound with diverse applications in military, polymer, rubber and pharmaceutical industries. The screening of the key pathway enzyme, keto acids decarboxylase, facilitated the production of 276.7 mg/L of BTO from arabinose in Escherichia coli. Through protein engineering of the rate-limiting enzyme KivD, which involved reducing the size of the binding pocket to accommodate a smaller substrate, its activity improved threefold, resulting in an increase in the BTO titer to 475.1 mg/L. Additionally, modular optimization was employed to adjust the expression levels of pathway genes, further enhancing BTO production to 705.1 mg/L. Conclusion The present study showcases a promising microbial platform for sustainable BTO production from arabinose. These works widen the spectrum of potential lignocellulosic products and lays the foundation for comprehensive utilization of lignocellulosic components.

Abstract Background Benevolent leadership is common in organizations, including hospitals, and is known to have positive effects on employees. Yet, nursing literature lacks sufficient research on its relationships with nurses’ behavior. Methods In March to April 2022, a cross-sectional study was carried out involving 320 nurses employed across various hospitals in Sichuan Province, China. Benevolent leadership, affective commitment, work engagement, and helping behavior were evaluated using the Benevolent Leadership Scale, Affective Commitment Scale, Work Engagement Scale, and Helping Behavior Questionnaire, respectively. The study employed structural equation model and the bootstrap method to investigate the proposed relationships. Results The SEM analysis results indicated a positive association between benevolent leadership and several outcomes among nurses. Specifically, benevolent leadership was found to be positively associated with nurses’ affective commitment (β = 0.58, p

The efficacy of selenium-chelating polypeptides derived from wheat protein hydrolysate (WPH-Se) includes enhancing antioxidant capacity, increasing bioavailability, promoting nutrient absorption, and improving overall health. This study aimed to enhance the bioavailability and functional benefits of exogenous selenium by chelating with wheat gluten protein peptides, thereby creating bioactive peptides with potentially higher antioxidant capabilities. In this study, WPH-Se was prepared with wheat peptide and selenium at a mass ratio of 2:1, under a reaction system at pH 8.0 and 80 °C. The in vitro antioxidant activity of WPH-Se was evaluated by determining the DPPH, OH, and ABTS radical scavenging rate and reducing capacity under different conditions, and the composition of free amino acids and bioavailability were also investigated at various digestion stages. The results showed that WPH-Se possessed significant antioxidant activities under different conditions, and DPPH, OH, and ABTS radical scavenging rates and reducing capacity remained high at different temperatures and pH values. During gastrointestinal digestion in vitro, both the individual digestate and the final digestate maintained high DPPH, OH, and ABTS radical scavenging rates and reducing capacity, indicating that WPH-Se was able to withstand gastrointestinal digestion and exert antioxidant effects. Post-digestion, there was a marked elevation in tryptophan, cysteine, and essential amino acids, along with the maintenance of high selenium content in the gastrointestinal tract. These findings indicate that WPH-Se, with its enhanced selenium and amino acid profile, serves as a promising ingredient for dietary selenium and antioxidant supplementation, potentially enhancing the nutritional value and functional benefits of wheat gluten peptides.

N-acetylglucosamine (GlcNAc) is an amino monosaccharide that has a variety of bioactivities and is widely used in pharmaceutical and food industries. Production of GlcNAc by chitin hydrolysis is limited by the supply of raw materials and encounters the risk of shellfish protein contamination. For efficient biosynthesis of GlcNAc, one challenge is to balance the carbon distribution between growth and production. Here, we applied the strategy of synergistic carbon utilization, in which glycerol supports cell growth and provides the acetyl group of GlcNAc while glucose serves as the precursor to glucosamine. The efficiency of GlcNAc production was stepwise improved by blocking the product re-uptake and degradation, strengthening the biosynthetic pathway and synergistically utilizing two carbon sources. With these efforts, the final strain produced 41.5 g/L GlcNAc with a yield of 0.49 g/g of total carbon sources. In addition, we also explored the feasibility of using acetate as a cheap carbon source to partly replace glycerol. This study provides a promising alternative strategy for sustainable and efficient production of GlcNAc.

Biosynthetic pathway of dencichine, a plant derived nature product that has found various pharmacological applications, is still elusive. Here, the authors design artificial pathways through retro-biosynthesis approaches and achieve its efficient production in E. coli by systematic metabolic and enzymatic engineering.

Abstract Objective From the perspective of informal social support, this paper analysed the impact of factors such as “Relationship with spouse”, “Relationship with Children”, “Financial support from children”, “Sibling support”, “Support from other friends and relatives” and “Borrowing costs” on the health poverty vulnerability of elderly people in rural China. Methods Based on the data of the China Health and Retirement Longitudinal Study (CHARLS) in 2018, the vulnerability of the rural elderly to health poverty was measured from two dimensions of health status and influencing factors of health status by the three-stage feasible generalized least square method. A quantile regression model was used to analyse the impact of six variables in the informal social support network on health poverty vulnerability: “Relationship with spouse”, “Relationship with children”, “Financial support from children”, " Sibling support”, " Support from other friends and relatives”, and “Borrowing costs”. Results When the poverty line standards were 2995 CNY/year and 4589 CNY/year, the health poverty vulnerability of the elderly population in rural China was 0.397 and 0.598 in 2018. In the analysis of informal social support, factors such as the relationship with spouse, relationship with children, borrowing costs, support from other friends and relatives, and sibling support had different impacts on the health poverty vulnerability of the rural elderly, who were classified into three groups according to their different vulnerabilities. Conclusion According to the analysis of the 2018 CHARLS database, the health poverty vulnerability of the elderly population was related to the informal social support network, and it is necessary to pay attention to the role of informal channels such as children, spouses, relatives and friends in daily care and financial support for rural elderly individuals. Meanwhile, the government and other formal organizations should also give full play to their supporting role for elderly individuals, who are highly vulnerable to health poverty, and their families.

Calvin-Benson-Bassham cycle (cbbL)-carrying bacteria in soil are essential to renew and circulate organic matter. However, the relation between cbbL-carrying bacteria and soil carbon dynamics under tillage managements, especially across the aggregate size remains unclear. Thus, in our study, soil organic carbon (SOC) storages, mineralization, and the cbbL-carrying bacterial community across five soil aggregate sizes were thoroughly investigated under four tillage treatments: conventional rotary tillage (CT), deep plowing (DP), subsoiling (SS), no-tillage (NT). We found macroaggregates (>2 mm) contributed most with regard to SOC stocks, whereas microaggregates (1 mm) with the highest cumulative SOC mineralization were found in subsoiling, whereas microaggregates had the lowest cumulative mineralization under no-tillage. By physically protecting, no-tillage specifically inhibited carbon dioxide (CO2) emissions in macroaggregates (>1 mm), whereas increased SOC levels and encouraged CO2 releases across microaggregates. Shifts in the co-occurrence network demonstrated that subsoiling promoted the joint symbiotic function between cbbL-carrying bacteria, the efficiency of matter and energy, and information transfer. And the keystone species, the enhanced cooperation and stochastic processes of autotrophic microorganisms under subsoiling lead to increased carbon fixation and reduced CO2 emissions in microaggregates with limited oxygen and nutrients. Overall, our work verified physical protection of large aggregates under no-tillage and improvement of microbial interaction efficiency under subsoiling. This may offer a theoretical foundation for the choice of tillage practices in fluvo-aquic soil regions.

Existing quorum sensing (QS) circuits are less sophisticated for regulating multiple sets of genes or operons. Here, the authors redesign the luxR-luxI intergenic sequence of the lux-type QS system and apply it to achieve diverse metabolic control in salicylic acid and 4-hydroxycoumarin biosynthesis in E. coli.

Stability and tunability are two desirable properties of microbial consortia-based bioproduction. Here, the authors integrate a caffeate-responsive biosensor into two and three strains coculture system to achieve autonomous regulation of strain ratios for coniferol and silybin/isosiltbin production, respectively.

IntroductionThe primary aim is to determine the factors associated with breast cancer-related lymphedema and to identify new associated factors for the recurrence of breast cancer and depression. The secondary objective is to investigate the incidence of breast cancer-related events (breast cancer-related lymphedema, recurrence of breast cancer, and depression). Finally, we want to explore and validate the complex relationship among multiple factors influencing breast cancer complications and breast cancer recurrence.Patients and methodsA cohort study of females with unilateral breast cancer will be conducted in West China Hospital between February 2023 and February 2026. Breast cancer survivors in the age range of 17-55 will be recruited before breast cancer surgery. We will recruit 1557 preoperative patients with a first invasive breast cancer diagnosis. Consenting breast cancer survivors will complete demographic information, clinicopathological factors, surgery information, baseline information, and a baseline depression questionnaire. Data will be collected at four stages: the perioperative stage, chemotherapy therapy stage, radiation therapy stage, and follow-up stage. Data including the incidence and correlation of breast cancer-related lymphedema, breast cancer recurrence, depression, and medical cost will be collected and computed through the four stages above. For every statistical analysis, the participants will be classified into two groups based on whether they develop secondary lymphedema. Incidence rates of breast cancer recurrence and depression will be calculated separately for groups. Multivariate logistic regression will be used to determine whether secondary lymphedema and other parameters can predict breast cancer recurrence.DiscussionOur prospective cohort study will contribute to establishing an early detection program for breast cancer-related lymphedema and recurrence of breast cancer, which are both associated with poor quality of life and reduced life expectancy. Our study can also provide new insights into the physical, economic, treatment-related and mental burdens of breast cancer survivors.

IntroductionVaccination is the most effective measure for prevention against infectious diseases in patients with systemic lupus erythematosus (SLE). Therefore, it is important to know SLE patients' attitudes toward influenza and pneumococcal vaccination. This study aimed to investigate the attitude toward influenza and pneumococcal vaccination among SLE patients in Southwest China and its influencing factors.MethodsA web-based questionnaire was conducted to collect data regarding SLE patients' demographics, history of infections, medications, comorbidities, attitudes toward infection and vaccination, rates of influenza and pneumococcal vaccination, and role of health professionals in promoting vaccination. Univariate and multivariate logistic regression analyses were conducted to assess the vaccination willingness-associated factors.ResultsA total of 251 patients participated in the survey and 240 questionnaires were completed and statistically analyzed. The influenza and pneumococcal vaccination rates were 8.3 and 1.7%, respectively. The top three reasons for non-vaccination were worrying about the SLE exacerbation or flare resulting from the vaccine or its adjuvants, being concerned about adverse events, and the lack of awareness of vaccine availability. More than half of the participants were willing to be vaccinated against influenza (56.2%) and pneumococcus (52.9%). Factors associated to the willingness to receive the influenza vaccine and pneumococcal vaccine were being afraid of infection, believing in the efficacy of influenza vaccination, lower family income, less perceived care from family members, perceived susceptibility to pneumococcal infection, and perceiving influenza and pneumococcal vaccination as beneficial for health.ConclusionsThe influenza and pneumococcal vaccination rates are low among SLE patients in Southwest China. The positive perspective of vaccination on health represented the most impacting factor on their willingness to undergo influenza and pneumococcal vaccination. Non-vaccinated patients were mainly concerned about exacerbation of the disease or adverse events caused by vaccines. It is important to improve the compliance with the guideline-recommended roles of health professionals and to promote the collaboration between rheumatology and primary care teams.

Abstract Aromatic polyketides have attractive biological activities and pharmacological properties. Different from other polyketides, aromatic polyketides are characterized by their polycyclic aromatic structure. The biosynthesis of aromatic polyketides is usually accomplished by the type II polyketide synthases (PKSs), which produce highly diverse polyketide chains by sequential condensation of the starter units with extender units, followed by reduction, cyclization, aromatization and tailoring reactions. Recently, significant progress has been made in characterization and engineering of type II PKSs to produce novel products and improve product titers. In this review, we briefly summarize the architectural organizations and genetic contributions of PKS genes to provide insight into the biosynthetic process. We then review the most recent progress in engineered biosynthesis of aromatic polyketides, with emphasis on generating novel molecular structures. We also discuss the current challenges and future perspectives in the rational engineering of type II PKSs for large scale production of aromatic polyketides.

Abstract The gut microbiota that inhabit our gastrointestinal tract are well known to play an important role in maintaining human health in many aspects, including facilitating the digestion and absorption of nutrients, protecting against pathogens and regulating immune system. Gut microbiota dysbiosis is associated with a lot of diseases, such as inflammatory bowel disease, allergy, obesity, cardiovascular and neurodegenerative diseases and cancers. With the increasing knowledge of the microbiome, utilization of probiotic bacteria in modulating gut microbiota to prevent and treat a large number of disorders and diseases has gained much interest. In recent years, aided by the continuous development of tools and techniques, engineering probiotic microbes with desired characteristics and functionalities to benefit human health has made significant progress. In this paper, we summarize the recent advances in design and construction of probiotics as living diagnostics and therapeutics for probing and treating a series of diseases including metabolic disorders, inflammation and pathogenic bacteria infections. We also discuss the current challenges and future perspectives in expanding the application of probiotics for disease treatment and detection. We intend to provide insights and ideas for engineering of probiotics to better serve disease therapy and human health.

A facile approach to in situ sonosynthesis and fabrication of nanocrystalline titanium dioxide (TiO2) in cotton fiber via low temperature sol-gel technique for superior ultraviolet resistance has been studied. Tetrabutyl titanate (TBT) was used as a precursor and ultrasonic cavitation was applied to synthesis TiO2 at low temperature followed by a simultaneous deposition in cotton fibers. Functionalized cotton fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive Spectroscopy (EDS), Thermo gravimetric Analysis (TGA), UV-Visible spectroscopy (UV-Vis) and X-ray diffraction (XRD) analysis. Ultraviolet resistant property of TiO2 assembled cotton fiber and was examined by UV transmittance analyzer. The results indicate that crystal TiO2-Nps at size between 17 and 19 nm include anatase and rutile structure was successfully synthesized and deposed in mesopores, lumen and surface of the cotton fibers. Durable protection against ultraviolet radiation was obtained, which exhibit significant prospect of using low temperature sonochemical synthesis of metal oxides nanoparticles and deposition in porous textiles for a broad range of functional application.

Based on the daily precipitation data from 2 474 stations in China and the National Centers for Environmental Prediction-Department of Energy (NCEP-DOE) daily reanalysis data, the extreme characteristics of two heavy precipitation events in Yunnan in winter of 2015 and the evolution characteristics of circulation anomalies are analyzed, and the relationship between precipitation anomalies and atmospheric low-frequency oscillations is discussed. The results suggest that the South Branch trough, water vapor and the South jet have anomalous characteristics during the two heavy rainfall events. The abnormal intensity of the first event is obviously stronger than that of the second event. The energy dispersion of Rossby waves originating from the North Atlantic in the middle and high latitudes plays an important role in the extreme precipitation in Yunnan province. In addition, the southwest jet in front of the South Branch Trough and the northwest propagation of the Philippine subtropical system are closely related to the extreme precipitation in Yunnan province. The wave action energy propagation direction, the convergence degree and the significant vertical circulation circle of Philippines-south China sea-Indochina peninsula-Yunnan in the first event are more conducive to the enhancement of low-frequency precipitation in Yunnan than those in the second event, which leads to the fact that the range and intensity of the first precipitation event are stronger than that of the second precipitation event.

The efficiency of producing glutarate, a valuable platform C5 compound, by engineered E. coli is low. Here, the authors achieve high titer and yield of glutarate production by pushing and pulling carbon flux in the native pathway and increasing intermediate influx using newly identified transporters.

Flavonoids are a class of secondary metabolites found in plant and fungus. They have been widely used in food, pharmaceutical, and nutraceutical industries owing to their significant biological activities, such as antiaging, antioxidant, anti-inflammatory, and anticancer. However, the traditional approaches for the production of flavonoids including chemical synthesis and plant extraction involved hazardous materials and complicated processes and also suffered from low product titer and yield. Microbial synthesis of flavonoids from renewable biomass such as glucose and xylose has been considered as a sustainable and environmentally friendly method for large-scale production of flavonoids. Recently, construction of microbial cell factories for efficient biosynthesis of flavonoids has gained much attention. In this article, we summarize the recent advances in microbial synthesis of flavonoids including flavanones, flavones, isoflavones, flavonols, flavanols, and anthocyanins. We put emphasis on developing pathway construction and optimization strategies to biosynthesize flavonoids and to improve their titer and yield. Then, we discuss the current challenges and future perspectives on successful strain development for large-scale production of flavonoids in an industrial level.

Engineering dynamic control can improve microbial production of target chemicals. Here, the authors design a sensor-regulator and RNAi based bifunctional dynamic control network that can simultaneously and independently turn up and down cellular metabolism for engineered muconic acid production in E. coli.

This research work deals with a qualitative analysis of extracts from Amaranthus viridis and Solanum nigrum plants as eco-friendly ultraviolet (UV) blocking finishes. The presence of flavonoid and phenolic contents in the plant extracts and the influence of concentrations towards UV blocking was studied. The plant extracts were obtained through solvent (aqueous and methanolic) extraction and coated onto cotton fabrics with the pad-dry-cure method. UV-visible and CIELAB spectroscopy analysis were carried out for the quantitative measurement of UV blocking and sequential analysis. The results show that loading of selected extracts on the fabric samples results in a significant enhancement in UV blocking. The treated fabrics show exceptional UV blocking in both UV-A and UV-B region, where the highest anti-UV values were obtained when the fabrics were treated with methanolic extracts. Furthermore, a considerable influence on CIELAB coordinates was found inordinate for methanolic extracts treated fabric compared to aqueous extracts.

Derived from the bacterial adaptive immune system, CRISPR technology has revolutionized conventional genetic engineering methods and unprecedentedly facilitated strain engineering. In this review, we outline the fundamental CRISPR tools that have been employed for strain optimization. These tools include CRISPR editing, CRISPR interference, CRISPR activation and protein imaging. To further characterize the CRISPR technology, we present current applications of these tools in microbial systems, including model- and non-model industrial microorganisms. Specially, we point out the major challenges of the CRISPR tools when utilized for multiplex genome editing and sophisticated expression regulation. To address these challenges, we came up with strategies that place emphasis on the amelioration of DNA repair efficiency through CRISPR-Cas9-assisted recombineering. Lastly, multiple promising research directions were proposed, mainly focusing on CRISPR-based construction of microbial ecosystems toward high production of desired chemicals.

Co-utilization of carbon sources in microbes is an important topic in metabolic engineering research. It is not only a way to reduce microbial production costs but also an attempt for either improving the yields of target products or decreasing the formation of byproducts. However, there are barriers in co-utilization of carbon sources in microbes, such as carbon catabolite repression. To overcome the barriers, different metabolic engineering strategies have been developed, such as inactivation of the phosphotransferase system and rewiring carbon assimilation pathways. This review summarizes the most recent developments of different strategies that support microbes to utilize two or more carbon sources simultaneously. The main content focuses on the co-utilization of glucose and pentoses, major sugars in lignocellulose.