A likely paleo-autotetraploidization event shaped the high conservation of Nyssaceae genome

Scientific knowledge about the ancestral genome of core eudicot plant kingdom can potentially have profound impacts on both basic and applied research,including evolution,genetics,genomics,ecology,agriculture,forestry,and global climate.To investigate which plant conserves best the core eudicots common ancestor genome,we compared Arcto-Tertiary relict Nyssaceae and 30 other eudicot plant families.The genomes of Davidia involucrata(a known living fossil),Camptotheca acuminata and Nyssa sinensis,one per existent genus of Nyssaceae,were performed comparative genomic analysis.We found that Nyssaceae originated from a single Nyssaceae common tetraploidization event(NCT)-autotetraploidization 28-31 Mya after the core eudicot common hexaploidization(ECH).We identified Nyssaceae orthologous and paralogous genes,determined its chromosomal evolutionary trajectory,and reconstructed the Nyssaceae most recent ancestor genome.D.involucrata genome contained the entire seven paleochromosomes and 17 ECH-generated eudicot common ancestor chromosomes and was the slowest in mutation among the analyzed 42 species of 31 plant families.Combing both its high retention of paleochromosomes and its low mutation rate,D.involucrata provides the best case in conservation of the core eudicot paleogenome.

Allotetraploidization event of Coptis chinensis shared by all Ranunculales

Coptis chinensis Franch.,also named Chinese goldthread is a member of Ranunculaceae in the order Ranunculales and represents an important lineage of early eudicots with traditional medicinal value.In our study,by using syntenic analysis combined with phylogenomic analysis of C.chinensis and four other representative genomes from basal and core eudicots,we confirmed that the WGD event in C.chinensis was shared by Aquilegia coerulea and Papaver somniferum L.and quickly occurred after Ranunculales diverged from other eudicots,likely a Ranunculales common tetraploidization(RCT).The synonymous nucleotide substitutions at synonymous sites distribution of syntenic blocks across these genomes showed that the evolutionary rate of the P.somniferum genome is faster than that of the C.chinensis genome by approximately 13.7%,possibly due to Papaveraceaes having an additional special tetraploidization event(PST).After Ks correction,the RCT dated to 115—130 million years ago(MYA),which was close to the divergence of Ranunculaceaes and Papaveraceaes approximately115.45—130.51 MYA.Moreover,we identified homologous genes related to polyploidization and speciation and constructed multiple sequence alignments with different reference genomes.Notably,the event-related subgenomes in the basal genomes all showed genomic fractionation bias,suggesting a likely allopolyploid nature of the RCT,PST and T-Alpha and T-Beta events in Tetracentron sinense.In addition,we detected that the sixteen P450 subfamilies were markedly expanded in the genomes of Ranunculales,and most of them were related to the RCT and PST events.We constructed a new platform for Early Eudicot Comparative Genomic Research(http://www.cgrpoee.top/index.html)to store more information.In summary,our findings support the WGD of C.chinensis shared by Ranunculales,which is likely an allotetraploidization event.This present effort offered new insights into the evolution of key polyploidization events and the genes related to secondary metabolites during the diversification of early eudicots.

Effects of silver-doping on properties of Cu(In,Ga)Se_(2) films prepared by Cu In Ga precursors

The AgCuInGa alloy precursors with different Ag concentrations are fabricated by sputtering an Ag target and a CuInGa target.The precursors are selenized in the H_(2)Se-containing atmosphere to prepare(Ag,Cu)(In,Ga)Se_(2)(ACIGS)absorbers.The beneficial effects of Ag doping are demonstrated and their mechanism is explained.It is found that Ag doping significantly improves the films crystallinity.This is believed to be due to the lower melting point of chalcopyrite phase obtained by the Ag doping.This leads to a higher migration ability of the atoms that in turn promotes grain boundary migration and improves the film crystallinity.The Ga enrichment at the interface between the absorber and the back electrode is also alleviated during the selenization annealing.It is found that Ag doping within a specific range can passivate the band tail and improve the quality of the films.Therefore,carrier recombination is reduced and carrier transport is improved.The negative effects of excessive Ag are also demonstrated and their origin is revealed.Because the atomic size of Ag is different from that of Cu,for the Ag/(Ag+Cu)ratio(AAC)≥0.030,lattice distortion is aggravated,and significant micro-strain appears.The atomic radius of Ag is close to those of In and Ga,so that the continued increase in AAC will give rise to the Ag;or Ag;defects.Both the structural and compositional defects degrade the quality of the absorbers and the device performance.An excellent absorber can be obtained at AAC of 0.015.

Modeling iron release from cast iron pipes in an urban water distribution system caused by source water switch

Significant iron release from cast iron pipes in water distribution systems(WDSs),which usually occurs during the source water switch period,is a great concern of water utilities because of the potential occurrence of"red water"and customer complaints.This study developed a new method which combined in-situ water stagnation experiments with mathematical models and numerical simulations to predict the iron release caused by source water switch.In-situ water stagnation experiments were conducted to determine the total iron accumulation in nine cast iron pipes in-service in Beijing when switching the local water to tre ated Danjiangkou Reservior water.Results showe d that the difference in the concentration increment of total iron in 24 hr(ΔCITI,24),i.e.short-term iron release,caused by source water switch was mainly dependent on the difference in the key quality parameters(pH,hardness,nitrate,Larson Ratio and dissolved oxygen(DO))between the two source waters.The iron release rate(RFe)after switch,i.e.long-term iron release,was closely related to the pipe properties as well as the DO and total residual chlorine(TRC)concentrations.Mathematical models ofΔCITI,24 and RFe were developed to quantitatively reveal the relationship between iron release and the key quality parameters.The RFe model could successfully combine with EPANET-MSX,a numerical simulator of water quality for WDSs to extend the iron release modeling from pipe level to network level.The new method is applicable to predicting iron release during source water switch,thus facilitating water utilities to take preventive actions to avoid"red water".

Characterization of bacterial community dynamics in a full-scale drinking water treatment plant

Understanding the spatial and temporal dynamics of microbial communities in drinking water systems is vital to securing the microbial safety of drinking water.The objective of this study was to comprehensively characterize the dynamics of microbial biomass and bacterial communities at each step of a full-scale drinking water treatment plant in Beijing,China.Both bulk water and biofilm samples on granular activated carbon（GAC） were collected over 9 months.The proportion of cultivable cells decreased during the treatment processes,and this proportion was higher in warm season than cool season,suggesting that treatment processes and water temperature probably had considerable impact on the R2 A cultivability of total bacteria.16 s rRNA gene based 454 pyrosequencing analysis of the bacterial community revealed that Proteobacteria predominated in all samples.The GAC biofilm harbored a distinct population with a much higher relative abundance of Acidobactena than water samples.Principle coordinate analysis and one-way analysis of similarity indicated that the dynamics of the microbial communities in bulk water and biofilm samples were better explained by the treatment processes rather than by sampling time,and distinctive changes of the microbial communities in water occurred after GAC filtration.Furthermore,20 distinct OTUs contributing most to the dissimilarity among samples of different sampling locations and 6 persistent OTUs present in the entire treatment process flow were identified.Overall,our findings demonstrate the significant effects that treatment processes have on the microbial biomass and community fluctuation and provide implications for further targeted investigation on particular bacteria populations.

Development of a pyrF-based counterselectable system for targeted gene deletion in Streptomyces rimosus

Streptomyces produces many valuable and important biomolecules with clinical and pharmaceutical applications.The development of simple and highly efficient gene editing tools for genetic modification of Streptomyces is highly desirable.In this study,we developed a screening system for targeted gene knockout using a uracil auxotrophic host(ΔpyrF)resistant to the highly toxic uracil analog of 5-fluoroorotic acid(5-FOA)converted by PyrF,and a non-replicative vector pKC1132-pyrF carrying the complemented pyrF gene coding for orotidine-5'-phosphate decarboxylase.The pyrF gene acts as a positive selection and counterselection marker for recombinants during genetic modifications.Single-crossover homologous integration mutants were selected on minimal medium without uracil by reintroducing pyrF along with pKC1132-pyrF into the genome of the mutantΔpyrF at the targeted locus.Double-crossover recombinants were generated,from which the pyrF gene,plasmid backbone,and targeted gene were excised through homologous recombination exchange.These recombinants were rapidly screened by the counterselection agent,5-FOA.We demonstrated the feasibility and advantage of using this pyrF-based screening system through deleting the otcR gene,which encodes the cluster-situated regulator that directly activates oxytetracycline biosynthesis in Streptomyces rimosus M4018.This system provides a new genetic tool for investigating the genetic characteristics of Streptomyces species.

基于临床证据的醒脑开窍针刺法适应症研究

目的通过文献计量学方法和循证医学理念研究方法探析醒脑开窍针刺法的适应病症。方法计算机检索中国期刊全文数据库(CNKI)、万方数据知识服务平台(Wanfang)、维普资讯中文期刊服务平台(VIP)、中国生物医学文献数据库(SinoMed)、The Cochrane Library、PubMed及EMbase中有关醒脑开窍针刺法的临床文献,检索时间为建库至2022年12月31日。依据世界卫生组织关于疾病和有关健康问题的国际统计分类(ICD11),并参考1994年国家中医药管理局制定的中医病证诊断疗效标准,对符合纳入标准的文献进行分类,并统计各病症的文献频次。结果最终纳入文献570篇,涉及9个病症系统,共54种病症,频次最高的6种病症依次为脑梗死、脑出血、血管性痴呆、颅脑损伤后昏迷、一氧化碳中毒迟发性脑病及抑郁症。结论醒脑开窍针刺法的适应病症广泛,优势病症相对集中,主要为脑梗死、脑出血等神经系统疾病。其中,有较高等级证据支持的病症有脑卒中(未特指为脑出血或脑梗死)、脑梗死、血管性痴呆、脑出血等34种病症。

Paleo-polyploidization in Lycophytes

Lycophytes and seed plants constitute the typical vascular plants.Lycophytes have been thought to have no paleo-polyploidization although the event is known to be critical for the fast expansion of seed plants.Here,genomic analyses including the homologous gene dot plot analysis detected multiple paleo-polyploidization events,with one occurring approximately 13–15 million years ago(MYA)and another about 125–142 MYA,during the evolution of the genome of Selaginella moellendorffii,a model lycophyte.In addition,comparative analysis of reconstructed ancestral genomes of lycophytes and angiosperms suggested that lycophytes were affected by more paleopolyploidization events than seed plants.Results from the present genomic analyses indicate that paleo-polyploidization has contributed to the successful establishment of both lineages—lycophytes and seed plants—of vascular plants.

Micro powder injection molding of boron carbide components with SiC-Al_(2)O_(3)-Y_(2)O_(3)sintering additives

Sintering additives and micro-powder injection molding offer an effective method to densify boron carbide(B_(4)C)and make B_(4)C components with complex shapes.By adjusting the proportion of three kinds of powders(SiC,Al_(2)O_(3)and Y_(2)O_(3)),four kinds of sintering additives were prepared.The feedstock uniformity,debinding behavior,phase composition and microstructure of micro injection molded B_(4)C components with different sintering additives were studied.The results showed that the defects such as lattice distortion and vacancy were introduced into ball milling,which increase the surface energy and benefit subsequent sintering densification.The feedstock had good uniformity and rheology that met the requirements of micro powder injection molding.After debinding,B_(4)C components had enough strength and showed certain sintering characteristics.The addition of sintering additives was beneficial to densification and sintering temperature reduction.The addition of sintering additives formed a second phase in the B_(4)C crystal and at the grain boundary of B_(4)C crystal,which changed the fracture mode from transgranular fracture to mixed fracture mechanism with transgranular fracture.