A unique role of the pyrimidine de novo synthesis enzyme ODCase in Lysobacter enzymogenes

Bacterial species of the genus Lysobacter are environmentally ubiquitous with strong antifungal biocontrol potential.Heat-stable antifungal factor(HSAF)secreted by the biocontrol bacterium Lysobacter enzymogenes OH11 has broad-spectrum and highly efficient antifungal activity.Studying the biosynthetic regulations of HSAF would lay an important foundation for strain engineering toward improved HSAF production.In this work,we demonstrate that Le0752,an orotidine-5´-phosphate decarboxylase enzyme(ODCase)catalyzing a pivotal step of the UMP de novo biosynthesis pathway,is vital for HSAF-mediated antimicrobial activities and growth of L.enzymogenes OH11,but not for twitching motility.This gene regulates the production of HSAF by affecting the expression of lafB,a key gene in the HSAF biosynthesis operon,through the transcription factor Clp.Interestingly,bioinformatics analysis revealed that Le0752 belongs to the Group III ODCases,whereas its homologs in the closely related genera Xanthomonas and Stenotrophomonas belong to Group I,which contains most ODCases from Gram-positive bacteria,Gram-negative bacteria and cyanobacteria.Moreover,the Group I ODCase PXO_3614 from the Xanthomonas oryzae pv.oryzae PXO99A strain complemented the Le0752 mutant in regulating HSAF-mediated antagonistic activity.Together,these results highlight the important requirement of de novo pyrimidine biosynthetic enzymes for antibiotic HSAF production in L.enzymogenes,which lays an important foundation for improving HSAF production via metabolic flow design and for dissecting the regulatory functions of bacterial ODCases.

Kinematic deformation and intensity assessment of the 2021 Maduo M_(S)7.4 earthquake in Qinghai revealed by high-frequency GNSS

Rapid acquisition of the kinematic deformation field and seismic intensity distribution of large earthquakes is crucial for postseismic emergency rescue,disaster assessment,and future seismic risk research.The advancement of GNSS observation and data processing makes it play an important role in this field,especially the high-frequency GNSS.We used the differential positioning method to calculate the 1 HZ GNSS data from 98 sites within 1000 km of the M_(S)7.4 Maduo earthquake epicenter.The kinematic deformation field and the distribution of the seismic intensity by using the peak ground velocity derived from displacement waveforms were obtained.The results show that:1)Horizontal coseismic response deformation levels ranging from 25 mm to 301 mm can be observed within a 1000 km radius from the epicenter.Coseismic response deformation on the east and west sides shows bilateral asymmetry,which markedly differs from the symmetry presented by surface rupture.2)The seismic intensity obtained through high-frequency GNSS and field investigations exhibits good consistency of the scope and orientation in the high seismic intensity area,although the former is generally slightly smaller than the latter.3)There may exist obstacles on the eastern side of the seismogenic fault.The Maduo earthquake induced a certain tectonic stress loading effect on the western Kunlun Pass-Jiangcuo fault(KPJF)and Maqin-Maqu segment,resulting in higher seismic risk in the future.

研发战略联盟对企业经营业绩的影响研究——来自创业板市场的经验证据

在创新驱动发展战略的指引下,近年来企业之间的研发战略联盟日趋增多。本文以创业板公司为研究对象,分析了研发战略联盟对企业经营业绩的影响及其作用机理。运用"匹配法和双重差分法"研究发现,企业缔结研发战略联盟对盈利能力具有显著的提升作用。在反映盈利能力的多项指标方面,缔结研发战略联盟的企业都强于未缔结研发战略联盟的企业。进一步研究发现,企业缔结研发战略联盟能够显著减少经营业绩风险,在反映盈利风险的多项指标方面,缔结研发战略联盟的企业都弱于未缔结研发战略联盟的企业。这为我们深入认识研发战略联盟对企业经营业绩的影响提供了理论基础和经验证据,并为企业着力提升竞争优势提供了决策依据和政策建议。

磁性纳米Fe_(3)O_(4)制备及在酵母RNA提取分析中的应用

磁珠法提取核酸是新冠病毒核酸检测的关键一环。基于此,以安全无毒的酵母RNA为对象,开发了一个涉及多学科化学知识交叉的综合实验,包括Fe_(3)O_(4)纳米磁珠制备与表征、RNA提取方法建立与机制探究、实际样品应用等。本实验既能锻炼学生综合运用化学知识和实验手段解决实际问题的能力,又能引导学生关注公共事件,培养其社会责任感。

Research progress in interface modification and thermal conduction behavior of diamond/metal composites

Diamond/metal composites are widely used in aerospace and electronic packaging fields due to their outstanding high thermal conductivity and low expansion.However,the difference in chemical properties leads to interface incompatibility between diamond and metal,which has a considerable impact on the performance of the composites.To improve the interface compatibility between diamond and metal,it is necessary to modify the interface of composites.This paper reviews the experimental research on interface modification and the application of computational simulation in diamond/metal composites.Combining computational simulation with experimental methods is a promising way to promote diamond/metal composite interface modification research.

Biocompatibility of marine magnetotactic ovoid strain MO-1 for in vivo application

Magnetotactic bacteria are capable of biosynthesizing magnetic nanoparticles,also called magnetosomes,and swimming along magnetic field lines.The abilities endow the whole cells of magnetotactic bacteria with such applications as targeted therapy and manipulation of microrobots.We have shown that the intact marine magnetotactic bacteria MO-1 kill efficiently antibiotic-resistant pathogen Staphylococcus aureus in vivo,but the biocompatibility of this marine bacterium is unknown.In this study,the strain MO-1 was chosen to analyze its biocompatibility and potential for biomedicine applications.Results showed that MO-1 cells could be guided at 37℃ under an external magnetic field and swim in the blood plasma and urine.They could keep active locomotivity within 40 min in the plasma and urine,although their velocity slowed down.When incubated with human cells,magnetotactic bacteria MO-1 had no obvious effects on cellular viability at low dose,while the cell toxicity increased with the augmentation of the quantity of the MO-1 cells added.In the in-vivo experiments,the median lethal dose of magnetotactic bacteria MO-1 in rats was determined to be 7.9×10^(10) bacteria/kg.These results provided the foundation for the biocompatibility and safety evaluations of magnetotactic bacteria MO-1 and suggested that they could be basically used in clinical targeted therapy.

Generation of a high-efficiency adenine base editor with TadA8e for developing wheat dinitroaniline-resistant germplasm

Base editing using CRISPR technologies is an invaluable tool for crop breeding. One of the major base editors, the adenine base editor(ABE), has been successfully used in both model plants and many crops.However, owing to limited editing efficiency, the ABE has been difficult to apply in polyploid crops such as allohexaploid bread wheat that often require simultaneous mutation of multiple alleles for fast breeding. We have designed a wheat high-efficiency ABE(Whie ABE), using the newly developed high-activity adenosine deaminase Tad A8 e. In vivo and in vitro analysis demonstrated the improved applicability of Tad A8 e over the commonly used Tad A7.10. Dinitroaniline is a widely used herbicide with high effectiveness and low toxicity to animals. However, wheat cultivars with tolerance to dinitroaniline are rare, limiting the application of dinitroaniline in wheat planting. Using A-to-G editing with Whie ABE, we found that a Met-to-Thr mutation in wheat tubulin alleles located on chromosomes 1 A, 1 B, 1 D, 4 A, and 4 D increased the resistance of wheat to dinitroaniline, revealing a dosage effect of edited tubulins in resistance. The Whie ABE promises to be a valuable editing tool for accelerating crop improvement and developing herbicide-resistant wheat germplasm.

Analysis of atmospheric effects on the continuous variable quantum key distribution

Atmospheric effects have significant influence on the performance of a free-space optical continuous variable quantum key distribution(CVQKD)system.In this paper,we investigate how the transmittance,excess noise and interruption probability caused by atmospheric effects affect the secret-key rate(SKR)of the CVQKD.Three signal wavelengths,two weather conditions,two detection schemes,and two types of attacks are considered in our investigation.An expression aims at calculating the interruption probability is proposed based on the Kolmogorov spectrum model.The results show that a signal using long working wavelength can propagate much further than that of using short wavelength.Moreover,as the wavelength increases,the influence of interruption probability on the SKR becomes more significant,especially within a certain transmission distance.Therefore,interruption probability must be considered for CVQKD by using long-signal wavelengths.Furthermore,different detection schemes used by the receiver will result in different transmission distances when subjected to individual attacks and collective attacks,respectively.

Screening of an Effective Degrading Strain for Treatment of Antibiotic Pharmaceutical Wastewater and Determination of Its Biological Properties

In this study,an effective antibiotic-degrading strain NG3 was isolated from activated sludge of antibiotic wastewater treatment.According to the results of morphological,physiological and biochemical identification and phylogenetical analysis of 16S r DNA sequence,the isolated strain belonged to Acinetobacter sp.,which was named Acinetobacter sp.NG3.Moreover,biological properties of the isolated strain were analyzed preliminarily,which provided a basis for the application of Acinetobacter sp.NG3 strain in efficient treatment of antibiotic industrial wastewater.

Strategic Analysis of High-tech Auctions

This paper deals with the security voting structure in an auction mechanism used to sell an item Of high-tech. The design of security voting structure allows the seller to choose between two objectives that are not mutually consistent. However, if the seller wants to maximize his revenue, he should retain some shares to benefit from the future dividends generated by the acquirer. In addition, if he wants to sell his high-tech to the most efficient candidate, he should sell all the shares.

Current Status of ADSCs-Enriched Fat Grafts in Plastic Surgery

Autologous fat grafting is an increasingly popular technique in plastic surgery for volume augmentation and rejuvenation.However,the unpredictability of long-term volume retention limits its clinical application.Various animal studies have documented the positive effects of adipose tissue-derived stem cells(ADSCs)on the acceleration of lipofilling.However,the results have been inconsistent,and there is an insufficient number of high-quality clinical studies to formulate evidence-based recommendations for ADSC-enriched fat grafts.Moreover,related technical standards,such as the final count of harvested ADSCs and the enrichment ratio,have not yet been established.This systematic review included all clinical trials on ADSC-enriched fat grafts in plastic surgery from PubMed in the past 10 years,as well as all registered clinical trials on ClinicalTrials.Gov.To examine the current landscape of ADSCs harvest,we summarize the current applications of ADSCs in the field of plastic surgery and discuss the current barriers to universal clinical use.

模仿目标临床试验在脑血管疾病领域的应用现状及展望

模仿目标临床试验是一种利用观察性研究数据来模仿随机临床试验结果的方法,近年来在临床研究中得到了广泛应用。模仿目标临床试验在脑血管疾病研究领域的应用,可以补充随机临床试验的不足,提高研究效率和可靠性,减少试验成本和时间,同时还可以扩大研究样本量,提高研究结果的可解释性和可推广性。未来,模仿目标临床试验在脑血管疾病研究中的应用还有待进一步发展和完善,从而更好地为脑血管疾病的治疗和预防提供科学依据。本文针对模仿目标临床试验在脑血管疾病领域的应用现状及未来展望进行了综述。

Chemoproteomics reveals the epoxidase enzyme for the biosynthesis of camptothecin in Ophiorrhiza pumila

Camptothecin is one of the most commonly used anticancer drugs worldwide,yet the downstream biosynthetic route from strictosidine to camptothecin has remained unclear for more than half a century.Here,we searched for proteins involved in camptothecin biosynthesis from the camptothecin-producing plant Ophiorrhiza pumila by chemoproteomics and identified Op CYP716E111.

Efficient blue-light-excitable copper(Ⅰ) coordination network phosphors for high-performance white LEDs

The blue-light-excitable phosphors play a crucial role in the high-performance white LEDs. Here, we report on two new Cu(Ⅰ) coordination network materials as yellow-emitting phosphors prepared by suitably expanded π-conjugated triazole ligands. Upon blue-light irradiation, these complexes exhibit efficient solid-state emission and enhanced photostability. Through incorporating the yellow phosphor and a commercial blue-green powder(BaSi_(2)N_(2)O_(2):Eu^(2+)) with a blue LED chip, the phosphor-converted LED devices display remarkable white emission properties. The experimental results demonstrate that the Cu(Ⅰ)coordination network materials function as promising blue-light excitable phosphors with great application potential for full-spectrum white LEDs.

中国上市公司战略联盟的审计定价研究——理论与证据

近年来中国上市公司之间的战略联盟大量涌现,产生了诸多新的审计问题。基于此背景,本文研究战略联盟的审计定价问题。本文发现,战略联盟是影响审计费用的重要因素。相较于未缔结战略联盟的公司而言,缔结战略联盟的公司的审计费用更高。联盟双方审计费用的增长变化存在非对称效应,年龄较大一方和资产规模较大一方,其审计费用增长更多。联盟的治理结构对审计费用具有调节效应。本文对中国注册会计师的调查和访谈进一步支持了上述发现。本文为我们深入认识战略联盟所产生的审计成本提供了理论基础和经验证据。

Improving Wind Forecasts Using a Gale-Aware Deep Attention Network

Numerical weather prediction of wind speed requires statistical postprocessing of systematic errors to obtain reliable and accurate forecasts.However,use of postprocessing models is often undesirable for extreme weather events such as gales.Here,we propose a postprocessing algorithm based on a gale-aware deep attention network to simultaneously improve wind speed forecasts and gale area warnings.Specifically,the algorithm includes both a galeaware loss function that focuses the model on potential gale areas,and an observation station supervision strategy that alleviates the problem of missing extreme values caused by data gridding.The effectiveness of the proposed model was verified by using data from 235 wind speed observation stations.Experimental results show that our model can produce wind speed forecasts with a root-mean-square error of 1.1547 m s^(-1),and a Hanssen–Kuipers discriminant score of 0.517,performance that is superior to that of the other postprocessing algorithms considered.

Characterization of Panax ginseng UDP- Glycosyltransferases Catalyzing Protopanaxatriol and Biosyntheses of Bioactive Ginsenosides F1 and Rhl in Metabolically Engineered Yeasts

Ginsenosides, the main pharmacologically active natural compounds in ginseng （Panax ginseng）, are mostly the glycosylated products of protopanaxadiol （PPD） and protopanaxatriol （PPT）. No uridine diphosphate glycosyltransferase （UGT）, which catalyzes PPT to produce PPT-type ginsenosides, has yet been reported. Here, we show that UGTPgl, which has been demonstrated to regio-specifically glycosylate the C20-OH of PPD, also specifically glycosylates the C20-OH of PPT to produce bioactive ginsenoside FI. We report the characterization of four novel UGT genes isolated from P. ginseng, sharing high deduced amino acid identity （〉84%） with UGTPgl. We demonstrate that UGTPgl00 specifically glycosylates the C6-OH of PPT to produce bioactive ginsenoside Rhl, and UGTPgl01 catalyzes PPT to produce F1, followed by the generation of ginsenoside Rgl from FI. However, UGTPgl02 and UGTPgl03 were found to have no detectable activity on PPT. Through structural modeling and site-directed mutagenesis, we identified several key amino acids of these UGTs that may play important roles in determining their activities and substrate regio-specificities. Moreover, we constructed yeast recombinants to biosynthesize F1 and Rhl by introducing the genetically engineered PPT-producing pathway and UGTPgl or UGTPgl00. Our study reveals the possible biosynthetic pathways of PPT-type ginsenosides in Panax plants, and provides a sound manufacturing approach for bioactive PPT-type ginsenosides in yeast via synthetic biology strategies.

Complete biosynthesis of the potential medicine icaritin by engineered Saccharomyces cerevisiae and Escherichia coli

Icaritin is a prenylflavonoid present in the Chinese herbal medicinal plant Epimedium spp. and is under investigation in a phase Ⅲ clinical trial for advanced hepatocellular carcinoma. Here, we report the biosynthesis of icaritin from glucose by engineered microbial strains. We initially designed an artificial icaritin biosynthetic pathway by identifying a novel prenyltransferase from the Berberidaceae-family species Epimedium sagittatum(EsPT2) that catalyzes the C8 prenylation of kaempferol to yield 8-prenlykaempferol and a novel methyltransferase GmOMT2 from soybean to transfer a methyl to C4’-OH of 8-prenlykaempferol to produce icaritin. We next introduced 11 heterologous genes and modified 12 native yeast genes to construct a yeast strain capable of producing 8-prenylkaempferol with high efficiency. GmOMT2 was sensitive to low pH and lost its activity when expressed in the yeast cytoplasm. By relocating GmOMT2 into mitochondria(higher pH than cytoplasm) of the 8-prenylkaempferol–producing yeast strain or co-culturing the 8-prenylkaempferol–producing yeast with an Escherichia coli strain expressing GmOMT2, we obtained icaritin yields of 7.2 and 19.7 mg/L, respectively. Beyond the characterizing two previously unknown plant enzymes and conducting the first biosynthesis of icaritin from glucose, we describe two strategies of overcoming the widespread issue of incompatible pH conditions encountered in basic and applied bioproduction research. Our findings will facilitate industrial-scale production of icaritin and other prenylflavonoids.

Correlation between tongue manifestations and glucose, total cholesterol, and high-density lipoprotein cholesterol in patients with acute cerebral infarction

OBJECTIVE: To analyze the association between tongue manifestations and the levels of glucose (GLU), total cholesterol(TCH), and high-density lipoprotein cholesterol(HDL-C) in subjects with acute cerebral infarction.METHODS: Hospitalized patients with first unilateral cerebral infarction in the Neurological Department of Xuanwu Hospital were included and the correlation between tongue fur color, fur nature,and the levels of GLU,TCH, HDL-C were analyzed.RESULTS: HDL level in the thin fur group was higher than that in the thick fur group(P=0.02). The difference in the levels of GLU,TCH, and HDL-C among the groups was significant(P<0.05), classified in terms of slippery, moist, and dry fur. Further comparison between the groups by Student-Newman-Keuls test showed that GLU level in the dry fur group was the highest. Moreover, the TCH level in the slippery fur group was higher than the other two groups.CONCLUSION: A correlation between tongue manifestations and GLU, TCH, HDL-C was identified in the patients with acute cerebral infarction.

The Arabidopsis catalase triple mutant reveals important roles of catalases and peroxisome-derived signaling in plant development

Hydrogen peroxide （H2O2） is generated in many metabolic processes. As a signaling molecule, H2O2 plays important roles in plant growth and development, as well as environmental stress response. In Arabidopsis, there are three catalase genes, CAT1, CAT2, and CAT3. The encoded catalases are predominately peroxisomal pro- teins and are critical for scavenging H2O2. Since CAT1 and CAT3 are linked on chromosome 1, it has been almost impossible to generate cat1/3 and cats1/2/3 mutants by traditional genetic tools. In this study, we constructed cat1/3 double mutants and cat1/22/3 triple mutants by CRISPR/Cas9 to investigate the role of catalases. The cat1/ 2/3 triple mutants displayed severe redox disturbance and growth defects under physiological conditionscompared with wild-type and the cat2/3 double mutants. Transcriptome analysis showed a more profound tran- scriptional response in the cat1/2/3 triple mutants compared to the cat2/3 mutants. These differentially expressed genes are involved in plant growth regulation as well as abiotic and biotic stress responses. In addition, expression of OXI1 （OXIDATIVE SIGNAL INDUCIBLE 1） and several MAPK cascade genes were changed dramatically in the catalase triple mutant, suggesting that H2O2 produced in peroxisomes could serve as a peroxisomal retrograde signal.