中国阿尔茨海默病早期预防指南(2024)

阿尔茨海默病是一种病因复杂的严重智力致残疾病,目前尚无有效的治疗方法。我国是世界上老年人口最多、增长最快的国家之一,也是阿尔茨海默病发病率较高的国家。因此,如何早期预防阿尔茨海默病的发生,是现今健康领域最重要的课题之一。我们在国内外相关研究的基础上,通过文献循证、干预研究实践、案例分析、经验总结和专家咨询,结合中国老年健康和社会文化特点,体现中国传统医学、武术、养生以及社区组织优势,制订出具有中国特色的阿尔茨海默病早期预防指南,涵盖了个人、家庭和社会三个层面的预防策略,从积极生活态度、社会活动参与、认知训练、体育锻炼、戒烟限酒、营养、睡眠,血压、血糖、血脂管理,体重和其他慢病管理以及中医开展针对阿尔茨海默病的一级预防。本指南仅供个人、家庭和社会开展阿尔茨海默病预防时参考。

Analysis of the electron transfer pathway in small laccase by EPR and UV-vis spectroscopy coupled with redox titration

Bacterial small laccases(SLAC) are promising industrial biocatalysts due to their ability to oxidize a broad range of substrates with exceptional thermostability and tolerance for alkaline p H. Electron transfer between substrate, copper centers, and O2is one of the key steps in the catalytic turnover of SLAC. However, limited research has been conducted on the electron transfer pathway of SLAC and SLAC-catalyzed reactions, hindering further engineering of SLAC to produce tunable biocatalysts for novel applications. Herein, the combinational use of electron paramagnetic resonance(EPR) and ultraviolet-visible(UV-vis) spectroscopic methods coupled with redox titration were employed to monitor the electron transfer processes and obtain further insights into the electron transfer pathway in SLAC. The reduction potentials for type 1 copper(T1Cu), type 2 copper(T2Cu) and type 3copper(T3Cu) were determined to be 367 ± 2 mV, 378 ± 5 m V and 403 ± 2 mV,respectively. Moreover, the reduction potential of a selected substrate of SLAC, hydroquinone(HQ), was determined to be 288 mV using cyclic voltammetry(CV). In this way, an electron transfer pathway was identified based on the reduction potentials. Specifically,electrons are transferred from HQ to T1Cu, then to T2Cu and T3Cu, and finally to O2.Furthermore, superhyperfine splitting observed via EPR during redox titration indicated a modification in the covalency of T2Cu upon electron uptake, suggesting a conformational alteration in the protein environment surrounding the copper sites, which could potentially influence the reduction potential of the copper sites during catalytic processes. The results presented here not only provide a comprehensive method for analyzing the electron transfer pathway in metalloenzymes through reduction potential measurements, but also offer valuable insights for further engineering and directed evolution studies of SLAC in the aim for biotechnological and industrial applications.

2023中国阿尔茨海默病数据与防控策略

本报告汇总了阿尔茨海默病及痴呆相关领域现有的最新数据,分析了我国阿尔茨海默病的流行病学、疾病负担、诊断治疗、风险因素、康复护理和疾病筛查等各方面的现状、问题以及趋势,针对目前中国民众和政策制定者最关心的问题,例如:阿尔茨海默病基本数据是怎样的?为什么知晓率相对提高,但是患者就诊愿望相对不高?如何采用有效的措施来应对,等等,提出了目前阿尔茨海默病的防控策略。特别强调了要大力开发经过验证的早期筛查和诊断工具,提供更有效治疗的创新药物,以及鼓励和建立全国性属地化社会互助支持网络。本报告期望能对医学专业人士、患者、家属和照护者、政府政策制定人员、养老机构等有所帮助,能为阿尔茨海默病的防治工作提供支撑,为相关卫生政策的制定提供依据和建议,有助于提高公众对阿尔茨海默病的认识,以期缓解我国阿尔茨海默病疾病的整体负担,推动我国健康老龄化的实现。

超薄ZnTi-LDH纳米片作为一种具有路易斯酸和布朗斯特酸的双功能光催化剂用于串联反应合成N-亚苄基苯胺

半导体光催化作为一种绿色可持续方法受到研究者的广泛关注.由于理论模型与实际催化剂存在较大差异,探究活性位点与光催化性能之间的关系一直是一个悬而未决的问题,需要寻找一种合适的材料深入了解该关系.超薄二维纳米材料因其活性位点占比较高,且活性位点种类相对简单而被认为是一种理想的模型.串联催化反应可以在单一体系中进行多步反应,避免了相对复杂的中间体分离和纯化,具有较大的经济和环保效益.在该过程中,独立的活性位点在不同的催化反应中起着重要的作用.目前已有一些关于光催化串联反应的研究报道,基于光催化过程,一般通过电子空穴分离效率或基于半导体价带理论来揭示,而活性位点与光催化性能之间的相互作用仍有待进一步研究.本文制备了两种不同厚度(1.4和4.0 nm)的超薄ZnTi-LDH纳米片用于光催化串联反应合成N-亚苄基苯胺,研究了该体系中的活性位点-催化性能的相互关系.X射线光电子能谱、红外光谱(FTIR)和电子自旋共振结果表明,减小ZnTi-LDH纳米片的厚度,可以暴露出更多的表面羟基和氧空位缺陷,形成配位不饱和Ti位点.紫外-可见光漫反射光谱和原位吸附FTIR光谱结果表明,在ZnTi-LDH纳米片上两种反应物(苯甲醇和硝基苯)能有效地化学吸附并活化.其中苯甲醇分子通过C-O···Ti的配位方式吸附并活化在配位不饱和Ti位点(L酸位点)上,而硝基苯分子以N-O···H-O的配位方式吸附并活化表面羟基的氢位点(B酸位点)上.在该体系中,光生空穴和光生电子能被有效利用,分别促进了苯甲醇选择性氧化为苯甲醛和硝基苯选择性还原为苯胺.阻抗和光电流实验结果表明,ZnTi-LDH纳米片厚度越薄,越有利于提高光生电子-空穴对的分离效率.由于其厚度的减小形成了氧空位,而氧空位作为电子的捕获中心,促进了光生电子-空穴对的分离.更薄的ZnTi-LDH纳米片具有更多的活性位点,不仅有利于反应物的活化,也有利于光生载流子的分离.因此,较薄的ZnTi-LDH纳米片实现了100%的高转化率和96%的高选择性.从分子水平上提出了该串联反应体系中分子活化协同光催化的机理.本文不仅为串联反应开发了具有独立活性位点的双功能催化剂,而且通过从分子水平上研究活性位点与催化性能之间的相互作用,对光催化机理提供了深入的认识.

A comparative analysis of China and other countries in metabolic engineering: Output, impact and collaboration

In recent years,metabolic engineering has made great progress in both academic research and industrial applications.However,we have not found any articles that specifically analyze the current state of metabolic engineering in China in comparison with other countries.Here,we review the current development and future trends of global metabolic engineering,conduct an in-depth benchmarking analysis of the development situation of China’s metabolic engineering,and identify current problems as well as future trends.We searched publications in the Scopus database from 2015 to September 2020 in the field of metabolic engineering,and analyzed the output in general,including publication trends,research distribution,popular journals,hot topics and vital institutions,but also analyzed the share of citations,field-weighted citation impact,and production in collaboration with strategic countries in science and technology.This study aims to serve as a reference for later studies,offering a comprehensive view of China’s contribution to metabolic engineering,and as a tool for the elaboration of national public policy in science and technology.

Effect of the codoping of N-H-O on the growth characteristics and defects of diamonds under high temperature and high pressure

Diamond crystals were synthesized with different doping proportions of N-H-O at 5.5 GPa-7.1 GPa and 1370℃-1450℃. With the increase in the N-H-O doping ratio, the crystal growth rate decreased, the temperature and pressure conditions required for diamond nucleation became increasingly stringent, and the diamond crystallization process was affected. [111] became the dominant plane of diamonds;surface morphology became block-like;and growth texture,stacking faults, and etch pits increased. The diamond crystals had a two-dimensional growth habit. Increasing the doping concentration also increased the amount of N that entered the diamond crystals as confirmed via Fourier transform infrared spectroscopy. However, crystal quality gradually deteriorated as verified by the red-shifting of Raman peak positions and the widening of the Raman full width at half maximum. With the increase in the doping ratio, the photoluminescence property of the diamond crystals also drastically changed. The intensity of the N vacancy center of the diamond crystals changed, and several Ni-related defect centers, such as the NE1 and NE3 centers, appeared. Diamond synthesis in N-H-O-bearing fluid provides important information for deepening our understanding of the growth characteristics of diamonds in complex systems and the formation mechanism of natural diamonds, which are almost always N-rich and full of various defect centers. Meanwhile, this study proved that the type of defect centers in diamond crystals could be regulated by controlling the N-H-O impurity contents of the synthesis system.

Diamond growth in a high temperature and high pressure Fe–Ni–C–Si system:Effect of synthesis pressure

Pressure is one of the necessary conditions for diamond growth.Exploring the influence of pressure on growth changes in silicon-doped diamonds is of great value for the production of high-quality diamonds.This work reports the morphology,impurity content and crystal quality characteristics of silicon-doped diamond crystals synthesized under different pressures.Fourier transform infrared spectroscopy shows that with the increase of pressure,the nitrogen content in the C-center inside the diamond crystal decreases.X-ray photoelectron spectroscopy test results show the presence of silicon in the diamond crystals synthesized by adding silicon powder.Raman spectroscopy data shows that the increase in pressure in the Fe-Ni-C-Si system shifts the Raman peak of diamonds from 1331.18 cm^(-1)to 1331.25 cm^(-1),resulting in a decrease in internal stress in the crystal.The half-peak width decreased from 5.41 cm^(-1)to 5.26 cm^(-1),and the crystallinity of the silicon-doped diamond crystals improved,resulting in improved quality.This work provides valuable data that can provide a reference for the synthesis of high-quality silicon-doped diamonds.

Response Characteristics of Flexible Risers in Offshore Compressed Air Energy Storage Systems

With the rapid development of marine renewable energy technologies, the demand to mitigate the fluctuation of variable generators with energy storage technologies continues to increase. Offshore compressed air energy storage (OCAES) is a novel flexible-scale energy storage technology that is suitable for marine renewable energy storage in coastal cities, islands, offshore platforms, and offshore renewable energy farms. For deep-water applications, a marine riser is necessary for connecting floating platforms and subsea systems. Thus, the response characteristics of marine risers are of great importance for the stability and safety of the entire OCAES system. In this study, numerical models of two kinds of flexible risers, namely, catenary riser and lazy wave riser, are established in OrcaFlex software. The static and dynamic characteristics of the catenary and the lazy wave risers are analyzed under different environment conditions and internal pressure levels. A sensitivity analysis of the main parameters affecting the lazy wave riser is also conducted. Results show that the structure of the lazy wave riser is more complex than the catenary riser;nevertheless, the former presents better response performance.

An international comprehensive benchmarking analysis of synthetic biology in China from 2015 to 2020

As a new interdisciplinary field,synthetic biology has led to valuable innovations in the fields of medicine,chemistry,agriculture,energy and environment.In this paper,we systematically review the development status of global synthetic biology in the past six years,and make an in-depth benchmarking analysis of the field in China.With the aid of Scopus and SciVal,we analyze the scholarly output of synthetic biology in the world and individual countries,including publication distribution,popular journals and eminent institutions.Furthermore,the research focus and concepts,citation impact and collaborations are also examined using numerical index methods such as the field-weighted citation impact(FWCI)and relative activity index(RAI),showing the differences between data more intuitively.This study aims to offer a comprehensive understanding of the research status of synthetic biology in China and the world,offering a benchmarked overview of the results as a reference to guide the development of this field in the future.

Surface functionalized Pt/SnNb_(2)O_(6)nanosheets for visible-light-driven the precise hydrogenation of furfural to furfuryl alcohol

Photocatalytic upgrading of renewable biomass is a promising way to relieve energy crisis and environmental pollution.However,low photocatalytic efficiency and uncontrollable selectivity still limit its development.Herein,ultrathin SnNb_(2)O_(6)nanosheets with high dispersed Pt nanoparticles(Pt/SN)were successfully developed as an efficient photocatalyst for the precise hydrogenation of furfural(FUR)to furfuryl alcohol(FOL)under visible light irradiation and exhibited the high conversion of FUR(99.9%)with the high selectivity for FOL(99.9%).It was revealed that SN with only 4.1 nm thickness possess good separation ability of photo-generated carriers and abundant surface Lewis acid sites(Nb^(5+))which would selectively chemisorb and activate FUR molecules via the Nb···O=C coordination.Meanwhile,Pt nanoparticles would gather photo-generated electrons for greatly promoting the generation of active H species to support the hydrogenation of FUR to FOL.The synergistic effects between SnNb_(2)O_(6)nanosheets and Pt nanoparticles remarkably facilitate the photocatalytic performance for hydrogenation.This work not only confirms the great potential of ultrathin nanosheet photocatalyst with functional metal sites for precise upgrading of biomass but also provides an in-depth view to understand the surface/interface interaction between reactant molecules and surface sites of a photocatalyst.

Knowledge,attitude and behaviour to evidence-based practice among psychiatric nurses:A cross-sectional survey

Objective To identify the status of knowledge,attitude,and behaviour toward evidence-based practice(EBP)among Chinese psychiatric nurses,and to examine the influencing factors of EBP behaviour.Methods We utilised a cross-sectional design.A total of 923 psychiatric nurses from 168 hospitals in 27 provinces in the mainland of China participated in our survey.The EBP questionnaire,the barriers to research utilisation scale and the facilitators to research utilisation scale were used for data collection via WeChat group from July 2018 to April 2019.Multiple regression analysis was used to analyse the influencing factors of psychiatric nurses’evidence-based practice behaviour.Results The score of Chinese psychiatric nurses’EBP attitude,behaviour and knowledge were 4.81±1.34,4.11±1.36 and 3.53±1.29,respectively.Multiple regression analysis showed that nurses’EBP behaviour was mainly determined by knowledge and attitude,which together explained 61.8%of the variance.The two top barriers were the dimensions of presentation and research.Facilitators include managerial support,employing nurses with research skills as models and providing advanced education on evidence-based nursing.Conclusion Psychiatric nurses have positive attitudes toward EBP,but their level of knowledge and behaviour is insufficient.Heavy workload,insufficient time,and a lack of knowledge and skills is the main barrier.Managerial support,employing nurses with research skills as models and providing advanced education are the main facilitators.

A precision-drive hysteresis model with an equal-density weight function for GMA feedforward compensation

Giant magnetostrictive actuators(GMAs) are a widely used type of micro-nano actuator, and they are greatly significant in the field of precision engineering. The accuracy of a GMA often depends on its hysteresis model. However, existing models have some limitations,including the difficulty of identifying their parameters and the tradeoff between the quantity of modeling data required and the level of precision achieved. To solve these problems, in this paper, we propose a Preisach inverse model based on equal-density segmentation of the weight function(E-Preisach). The weight function used to calculate the displacement is first discretized. Then, to obtain a finer weight distribution, the discretized geometric units are uniformly divided by area. This can further minimize the output displacement span, and it produces a higher-precision hysteresis model. The process of parameter identification is made easier by this approach, which also resolves the difficulty of obtaining high precision using a small amount of modeling data. The Preisach and the E-Preisach inverse models were investigated and compared using experiments. At frequencies of 1 and 5 Hz, it was found that the E-Preisach inverse model decreases the maximum error of the feedforward compensation open-loop control to within 1 μm and decreases the root-mean-square error in displacement to within0.5 μm without the need to increase the number of measured hysteresis loops. As a result, the E-Preisach inverse model streamlines the structure of the model and requires fewer parameters for modeling. This provides a high-precision modeling method using a small amount of modeling data;it will have applications in precision engineering fields such as active vibration damping and ultra-precision machining.

Transcriptome Analysis and Morphological Changes in Response to Waterlogging in Iris pseudacorus

Iris pseudacorus is a widely cultivated and studied ornamental plant with a large biomass,strong adaptability and extensive management.Moreover,it has the ability to decontaminate and enrich heavy metals.However,few studies have been conducted on its submergence tolerance with little known about the molecular response of I.pseudacorus to flooding.Morphologically,I.pseudacorus had strong adaptability to waterlogging,the aerenchyma was gradually enlarged and adventitious roots developed between 0 and 14 d.The transcriptome data showed that the differentially expressed genes counts in plants flooded for 2 h,4 h,12 h and 24 h compared with the unflooded controls were 3555,9439,10734,and 4997,respectively.For GO term entries enriched by different genes,many biological processes,cell components and molecular processes in the I.pseudacorus roots were affected by flooding stress.Pathways enrichment analysis showed DEGs involved in hormone signal transduction pathways,glucose metabolism,glycolysis,and fermentation.The quantitative real-time PCR analysis of DEGs was basically consistent with the trend of transcriptome data,indicating reliability of the transcriptome data.The transcriptome analysis showed that formation of aerenchyma and adventitious roots was mainly induced by IAA(auxin)and accompanied by other hormone signals.Energy production was the primary coping mechanism of I.pseudacorus when aerenchyma was not sufficiently enlarged under water flooding.These results laid a foundation for further study on the mechanism of submerging-tolerance of I.pseudacorus and other aquatic plants.

Strain-Enabled Control of Chiral Magnetic Structures in MnSeTe Monolayer

Chiral magnetic states are promising for future spintronic applications. Recent progress of chiral spin textures in two-dimensional magnets, such as chiral domain walls, skyrmions, and bimerons, have been drawing extensive attention. Here, via first-principles calculations, we show that biaxial strain can effectively manipulate the magnetic parameters of the Janus Mn Se Te monolayer. Interestingly, we find that both the magnitude and the sign of the magnetic constants of the Heisenberg exchange coupling, Dzyaloshinskii–Moriya interaction and magnetocrystalline anisotropy can be tuned by strain. Moreover, using micromagnetic simulations, we obtain the distinct phase diagram of chiral spin texture under different strains. Especially, we demonstrate that abundant chiral magnetic structures including ferromagnetic skyrmion, skyrmionium, bimeron, and antiferromagnetic spin spiral can be induced in the Mn Se Te monolayer. We also discuss the effect of temperature on these magnetic structures. The findings highlight the Janus Mn Se Te monolayer as a good candidate for spintronic nanodevices.

Gene finding by integrating gene finders

Gene finding, the accurate annotation of genomic DNA, has become one of the central topics in biological research. Although various computational methods (gene finders) have been proposed and developed, they all have their own limitations in gene findings. In this paper, we introduce an integrating gene finder, which combines the results of several existing gene finders together, to improve the accuracy of gene finding. Four integration schemes, based on majority voting, are developed for the analysis of two datasets – the basic dataset and the testing dataset. The basic dataset consists of 1500 DNA sequences and the testing dataset consists of 103 DNA sequences. It is demonstrated that a simple integration (a simple voting for each nucleotide) can significantly improve the finding performance, and removing confusing gene finders, caused by poor performance or redundant results, is important for a further improvement of the integration. The best prediction results are obtained using weighted majority voting, aided by the mRMR (Minimum Redundancy Maximum Relevance) (Peng, 2005) method for the gene finder selection. The prediction accuracies are 84.16% and 90.06% for the basic dataset and testing dataset respectively, which are better than any individual gene finding software in our research.

Two-Tier GCT Based Approach for Attack Detection

The frequent attacks on network infrastructure, using various forms of denial of service attacks, have led to an increased need for developing new techniques for analyzing network traffic. If efficient analysis tools were available, it could become possible to detect the attacks and to take action to weaken those attacks appropriately before they have had time to propagate across the network. In this paper, we propose an SNMP MIB oriented approach for detecting attacks, which is based on two-tier GCT by analyzing causal relationship between attacking variable at the attacker and abnormal variable at the target. According to the abnormal behavior at the target, GCT is executed initially to determine preliminary attacking variable, which has whole causality with abnormal variable in network behavior. Depending on behavior feature extracted from abnormal behavior, we can recognize attacking variable by using GCT again, which has local causality with abnormal variable in local behavior. Proactive detecting rules can be constructed with the causality between attacking variable and abnormal variable, which can be used to give alarms in network management system. The results of experiment showed that the approach with two-tier GCT was proved to detect attacks early, with which attack propagation could be slowed through early detection.

Targeting the Warburg effect:A revisited perspective from molecular mechanisms to traditional and innovative therapeutic strategies in cancer

Cancer reprogramming is an important facilitator of cancer development and survival,with tumor cells exhibiting a preference for aerobic glycolysis beyond oxidative phosphorylation,even under sufficient oxygen supply condition.This metabolic alteration,known as the Warburg effect,serves as a significant indicator of malignant tumor transformation.The Warburg effect primarily impacts cancer occurrence by influencing the aerobic glycolysis pathway in cancer cells.Key enzymes involved in this process include glucose transporters(GLUTs),HKs,PFKs,LDHs,and PKM2.Moreover,the expression of transcriptional regulatory factors and proteins,such as FOXM1,p53,NF-κB,HIF1a,and c-Myc,can also influence cancer progression.Furthermore,lncRNAs,miRNAs,and circular RNAs play a vital role in directly regulating the Warburg effect.Additionally,gene mutations,tumor microenvironment remodeling,and immune system interactions are closely associated with the Warburg effect.Notably,the development of drugs targeting the Warburg effect has exhibited promising potential in tumor treatment.This comprehensive review presents novel directions and approaches for the early diagnosis and treatment of cancer patients by conducting in-depth research and summarizing the bright prospects of targeting the Warburg effect in cancer.

The transition from galaxy-wide gas inflow to outflow in quasar host galaxies

Galactic-scale outflows driven by active galactic nuclei(AGNs) represent a commonly invoked feedback mechanism within galaxy evolution models.However,the interactions among interstellar gas on galactic scales,the propagation of AGN outflows,and the fundamental parameters of AGNs during their evolutionary processes remain poorly understood.Notably,powerful nuclear outflows are typically associated with the early stages of AGN activity,which are characterized by high accretion rates and weak narrow emission lines.In our analysis of a sample of quasars hosting Mg ii narrow absorption lines(NALs) obtained from the Sloan Digital Sky Survey,we identify a previously unobserved phenomenon wherein galaxy-scale inflow transitions to outflow dominance,concurrent with a notable increase in the strength of the narrow [O Ⅲ] line,achieving a confidence level of 6.7σ.This indicates that while nuclear outflows diminish,galaxy-wide outflows intensify as AGNs evolve.These findings suggest that early-stage outflows interact with the interstellar medium on a galactic scale,thereby facilitating a gradual transition to galaxy-wide outflows.This provides observational support for the hypothetical multi-stage propagation of AGN outflows that globally regulates galaxy evolution.

ECMpy 2.0:A Python package for automated construction and analysis of enzyme-constrained models

Genome-scale metabolic models(GEMs)have been widely employed to predict microorganism behaviors.However,GEMs only consider stoichiometric constraints,leading to a linear increase in simulated growth and product yields as substrate uptake rates rise.This divergence from experimental measurements prompted the creation of enzyme-constrained models(ecModels)for various species,successfully enhancing chemical pro-duction.Building upon studies that allocate macromolecule resources,we developed a Python-based workflow(ECMpy)that constructs an enzyme-constrained model.This involves directly imposing an enzyme amount constraint in GEM and accounting for protein subunit composition in reactions.However,this procedure de-mands manual collection of enzyme kinetic parameter information and subunit composition details,making it rather user-unfriendly.In this work,we’ve enhanced the ECMpy toolbox to version 2.0,broadening its scope to automatically generate ecGEMs for a wider array of organisms.ECMpy 2.0 automates the retrieval of enzyme kinetic parameters and employs machine learning for predicting these parameters,which significantly enhances parameter coverage.Additionally,ECMpy 2.0 introduces common analytical and visualization features for ecModels,rendering computational results more user accessible.Furthermore,ECMpy 2.0 seamlessly integrates three published algorithms that exploit ecModels to uncover potential targets for metabolic engineering.ECMpy 2.0 is available at https://github.com/tibbdc/ECMpy or as a pip package(https://pypi.org/project/ECMpy/).

Multi-modular metabolic engineering of heme synthesis in Corynebacterium glutamicum

Heme,an iron-containing porphyrin derivative,holds great promise in fields like medicine,food production and chemicals.Here,we developed an engineered Corynebacterium glutamicum strain for efficient heme production by combining modular engineering and RBS engineering.The whole heme biosynthetic pathway was methodically divided into 5-ALA synthetic module,uroporphyrinogen III(UPG III)synthetic module and heme synthetic module for further construction and optimization.Three heme synthetic modules were compared and the siroheme-dependent(SHD)pathway was identified to be optimal in C.glutamicum for the first time.To further improve heme production,the expression of genes in UPG III synthetic module and heme synthetic module was coordinated optimized through RBS engineering,respectively.Subsequently,heme oxygenase was knocked out to reduce heme degradation.The engineered strain HS12 showed a maximum iron-containing porphyrin derivatives titer of 1592 mg/L with the extracellular secretion rate of 45.5%in fed-batch fermentation.Our study constructed a C.glutamicum chassis strain for efficient heme accumulation,which was beneficial for the advancement of efficient heme and other porphyrins production.