Genome of a citrus rootstock and global DNA demethylation caused by heterografting

Grafting is an ancient technique used for plant propagation and improvement in horticultural crops for at least 1,500 years.Citrus plants,with a seed-to-seed cycle of 5–15 years,are among the fruit crops that were probably domesticated by grafting.Poncirus trifoliata,a widely used citrus rootstock,can promote early flowering,strengthen stress tolerance,and improve fruit quality via scion–rootstock interactions.Here,we report its genome assembly using PacBio sequencing.We obtained a final genome of 303 Mb with a contig N50 size of 1.17Mb and annotated 25,680 protein-coding genes.DNA methylome and transcriptome analyses indicated that the strong adaptability of P.trifoliata is likely attributable to its special epigenetic modification and expression pattern of resistance-related genes.Heterografting by using sweet orange as scion and P.trifoliata as rootstock and autografting using sweet orange as both scion and rootstock were performed to investigate the genetic effects of the rootstock.Single-base methylome analysis indicated that P.trifoliata as a rootstock caused DNA demethylation and a reduction in 24-nt small RNAs(sRNAs)in scions compared to the level observed with autografting,implying the involvement of sRNA-mediated graft-transmissible epigenetic modifications in citrus grafting.Taken together,the assembled genome for the citrus rootstock and the analysis of graft-induced epigenetic modifications provide global insights into the genetic effects of rootstock–scion interactions and grafting biology.

Hollow Bio-derived Polymer Nanospheres with Ordered Mesopores for Sodium-Ion Battery

Bio-inspired hierarchical self-assembly provides elegant and powerful bottom-up strategies for the creation of complex materials.However,the current self-assembly approaches for natural bio-compounds often result in materials with limited diversity and complexity in architecture as well as microstructure.Here,we develop a novel coordination polymerization-driven hierarchical assembly of micelle strategy,using phytic acid-based natural compounds as an example,for the spatially controlled fabrication of metal coordination bio-derived polymers.The resultant ferric phytate polymer nanospheres feature hollow architecture,ordered meso-channels of^12 nm,high surface area of 401 m2 g−1,and large pore volume of 0.53 cm3 g−1.As an advanced anode material,this bio-derivative polymer delivers a remarkable reversible capacity of 540 mAh g−1 at 50 mA g−1,good rate capability,and cycling stability for sodium-ion batteries.This study holds great potential of the design of new complex bio-materials with supramolecular chemistry.

Chlorinated Thiazole-Based Low-Cost Polymer Donors for High Efficiency Binary and Ternary Organic Solar Cells

In this work,novel D-A alternating polymers(PJ-1,PJ-2,and PJ-3)with chlorinated benzodithiophene and chlorinated thiazole units were synthesized via gradual chlorination.These polymers could be obtained readily through a few concise synthesis steps.Among them,PJ-1 displayed desirable properties including energy levels,crystallinity,and charge transport capabilities.The binary and ternary organic solar cells(OSCs)fabricated based on PJ-1 displayed significant power conversion efficiency(PCE)of 15.02%and 19.12%,respectively,placing them among the highest reported for ternary OSCs.Notably,the PJ1-based devices also showcased one of the highest figure-of-merit values,indicating their promising potential for future applications.This study offers valuable insights and supports the development of costeffective and high-performance polymer donors for the generation of OSCs.

Genome of Wild Mandarin and Domestication History of Mandarin

Mandarin （Citrus reticulata） is one of the most important citrus crops worldwide. Its domestication is believed to have occurred in South China, which has been one of the centers of mandarin cultivation for four millennia. We collected natural wild populations of mandarin around the Nanling region and cultivated landraces in the vicinity. We found that the citric acid level was dramatically reduced in cultivated mandarins. To understand genetic basis of mandarin domestication, we de novo assembled a draft genome of wild mandarin and analyzed a set of 104 citrus genomes. We found that the Mangshan mandarin is a primitive type and that two independent domestication events have occurred, resulting in two groups of cultivated mandarins （MD1 and MD2） in the North and South Nanling Mountains, respectively. Two bottlenecks and two expansions of effective population size were identified for the MD1 group of cultivated mandarins. However, in the MD2 group there was a long and continuous decrease in the population size. MD1 and MD2 mandarins showed different patterns of interspecific introgression from cultivated pummelo species. We identified a region of high divergence in an aconitate hydratase （ACO） gene involved in the regulation of citrate content, which was possibly under selection during the domestication of mandarin. This study provides concrete genetic evidence for the geographical origin of extant wild mandarin populations and sheds light on the domestication and evolutionary history of mandarin.

Antibody Cocktail Exhibits Broad Neutralization Activity Against SARS-CoV-2 and SARS-CoV-2 Variants

Severe acute respiratory syndrome coronavirus 2(SARS-Co V-2)has precipitated multiple variants resistant to therapeutic antibodies.In this study,12 high-affinity antibodies were generated from convalescent donors in early outbreaks using immune antibody phage display libraries.Of them,two RBD-binding antibodies(F61 and H121)showed high-affinity neutralization against SARS-Co V-2,whereas three S2-target antibodies failed to neutralize SARS-Co V-2.Following structure analysis,F61 identified a linear epitope located in residues G446–S494,which overlapped with angiotensinconverting enzyme 2(ACE2)binding sites,while H121 recognized a conformational epitope located on the side face of RBD,outside from ACE2 binding domain.Hence the cocktail of the two antibodies achieved better performance of neutralization to SARS-Co V-2.Importantly,these two antibodies also showed efficient neutralizing activities to the variants including B.1.1.7 and B.1.351,and reacted with mutations of N501 Y,E484 K,and L452 R,indicated that it may also neutralize the recent India endemic strain B.1.617.The unchanged binding activity of F61 and H121 to RBD with multiple mutations revealed a broad neutralizing activity against variants,which mitigated the risk of viral escape.Our findings revealed the therapeutic basis of cocktail antibodies against constantly emerging SARS-Co V-2 variants and provided promising candidate antibodies to clinical treatment of COVID-19 patients infected with broad SARS-Co V-2 variants.

Microstructure induced galvanic corrosion evolution of SAC305 solder alloys in simulated marine atmosphere

Motivated by the increasing use of Sn-3.0 Ag-0.5 Cu(SAC305)solder in electronics worked in marine atmospheric environment and the uneven distribution of Ag3Sn and Cu6Sn5 intermetallic compounds(IMCs)inβ-Sn matrix,comb-like electrodes have been designed for in-situ EIS measurements to study the microstructure induced galvanic corrosion evolution of SAC305 solder in simulated marine atmosphere with high-temperature and high-humidity.Results indicate that in-situ EIS measurement by comb-like electrodes is an effective method for corrosion evolution behavior study of SAC305 solder.Besides,the galvanic effect between Ag3Sn IMCs andβ-Sn matrix can aggravate the corrosion of both as-received and furnace-cooled SAC305 solder as the exposure time proceeds in spite of the presence of corrosion product layer.Pitting corrosion can be preferentially found on furnace-cooled SAC305 with larger Ag3Sn grain size.Moreover,the generated inner stress during phases transformation process with Sn3O(OH)2Cl2 as an intermediate and the possible hydrogen evolution at local acidified sites are supposed to be responsible for the loose,porous,cracked,and non-adherent corrosion product layer.These findings clearly demonstrate the corrosion acceleration behavior and mechanism of SAC305 solder,and provide potential guidelines on maintenance of microelectronic devices for safe operation and longer in-service duration.

Temperature and NaCl deposition dependent corrosion of SAC305 solder alloy in simulated marine atmosphere

The stable operation of electronic devices in marine atmospheric environment is affected by the corrosion deterioration of solder joints,and the effects by atmosphere temperature and chloride deposition are critical.In this work,NaCl deposition and temperature dependent corrosion of Pb-free SAC305 solder in simulated marine atmosphere has been investigated.The results indicate that higher NaCl deposition prolongs the surface wetting time and leads to the final thicker saturated electrolyte film for further corrosion.Higher temperature accelerates the evaporation and contributes to the final thinner saturated NaCl electrolyte film.Besides,the corrosion control process varies under the initially covered thicker NaCl electrolyte layer and under the final saturated much thinner NaCl electrolyte film as the evaporation proceeds.Moreover,the ready oxygen availability through the final thinner saturated NaCl electrolyte film facilitates the formation of corrosion product layer mainly of electrochemically stable SnO2,but higher temperature leads to the final corrosion product layer with smaller crystal size and large cracks.The findings clearly demonstrate the effects of NaCl deposition and temperature on corrosion evolution of SAC305 solder joints and are critical to the daily maintenance of electronic devices for longer service life in marine atmosphere.

Epidemiological Characteristics of Human Rabies——Shandong Province,China,2010-2020

Introduction:Rabies is a viral zoonotic disease that causes progressive and fatal inflammation in the brain.Rabies has caused more than 5,000 human deaths in Shandong Province since 1955.This study aimed to analyze the epidemiological characteristics of human rabies in Shandong Province from 2010 to 2020 and to provide a scientific basis for policy changes.Methods:The data of reported human rabies cases from 2010 to 2020 were obtained from China’s National Notifiable Disease Reporting System,and data related to exposure and post-exposure prophylaxis(PEP)of the cases were acquired through case investigation.Results:A total of 414 human rabies cases were reported in Shandong Province from 2010 to 2020.Out of the 414 total cases,87.20%were primarily farmers;83.10%were over 40 years old.70.29%(265/377)belonged to categoryⅢexposure;and 96.67%(377/390)were exposed to the virus through infected dogs.The vaccine inoculation rate of these cases after exposure was only 8.85%;1.03%(4/390)had been vaccinated with rabies immunoglobulin,developing the disease 11 to 13 days after categoryⅢexposure.Conclusions:Dogs were still the primary animal hosts.Most rabies patients died due to no or inadequate post-exposure prophylaxis.Vaccine inoculation rates for dogs should reach the target of 70%as soon as possible.Health departments should improve the accessibility and quality of PEP;and improve the health literacy of the elderly in rural areas.

Polymorphism of pharmaceutical molecules:perspectives on nucleation

Polymorphism is a widespread phenomenon observed in more than half of all drug substances.Various polymorphs frequently possess different physical,chemical,mechanical and thermal properties that can profoundly affect the bioavailability,stability and other performance characteristics of the drug.Accordingly,the elucidation of the relationship between the particular polymorph of a pharmaceutical molecule and its functional properties is crucial to select the most suitable polymorph of the pharmaceutical molecule for development into a drug product.This review briefly introduces recent advances in the discovery and control of the polymorphs of pharmaceutical molecules,in terms of the enhancement of the selective nucleation of a particular polymorph.In the light of this,some cases discussed in the following is to be considered controversial.

NEW INSIGHTS INTO THE PHYLOGENY AND SPECIATION OF KUMQUAT (FORTUNELLA SPP.) BASED ON CHLOROPLAST SNP, NUCLEAR SSR AND WHOLE-GENOME SEQUENCING

Kumquat(Fortunella spp.)is a fruit and ornamental crop worldwide due to the palatable taste and high ornamental value of its fruit.Although Fortunella is classified into the economically important true citrus fruit tree group together with Citrus and Poncirus,few studies have been focused on its evolutionary scenario.In this study,analysis of five chloroplast loci and 47 nuclear microsatellites(nSSR)loci from 38 kumquat and 10 citrus accessions revealed the independent phylogeny of Fortunella among citrus taxa,and that Fortunella mainly comprises two populations:CUL,cultivated Fortunella spp.(F.margarita,F.crassifolia and F.japonica);and HK,wild Hong Kong kumquat(Fortunella hindsii).Genomic analysis based on whole-genome SNPs indicated that the allele frequency of both pupations deviated from the neutral selection model,suggesting directional selection was a force driving their evolutions.CUL exhibited lower genomic diversity and higher linkage strength than HK,suggesting artificial selection involved in its origin.A high level of genetic differentiation(Fst=0.364)was detected and obviously asynchronous demographic changes were observed between CUL and HK.Based on these results,a new hypothesis for the speciation of Fortunella is proposed.

A Limited Spreading Event of COVID-19 Caused by Delta Variant in a Cosmetic Hospital—Yantai City,Shandong Province,China,2021

Summary What is already known about this topic?Coronavirus disease 2019(COVID-19)outbreaks in the past were mostly caused by overseas transmission,but if control measures are not appropriately applied,domestic transmission could also cause large-scale local epidemics.What is added by this report?This report covers all information of epidemic investigation processes,epidemiological characteristics and exposure history,transmission chains,sequencing results as well as public health measures taken for the COVID-19 cluster epidemic caused by the Delta variant in a cosmetic hospital in Yantai City in August 2021.What are the implications for public health practice?The information provided in this report,including active case finding,community management,and mass testing,may assist public health professionals in dealing with local COVID-19 epidemics caused by domestic transmission.