A new geminialphasatellite associated with wheat dwarf virus identified in winter barley in France.

Using a high-throughput sequencing (HTS) approach, we report the discovery of a new alphasatellite identified in a winter barley plant collected in France in 2022 that was also infected by wheat dwarf virus (WDV). The presence of the satellite and of WDV was confirmed by several independent PCR assays, and the complete genome sequence was determined. The circular satellite genome is 1424 nt long and shows typical hallmarks of members of the subfamily Geminialphasatellitinae, including a replication-associated hairpin with a CAGTATTAC sequence and a Rep-encoding open reading frame (ORF). It also possesses a second ORF, embedded in a different frame within the Rep ORF, which is also observed in clecrusatellites and a few other members of the family Alphasatellitidae. Pairwise sequence comparisons and phylogenetic analysis showed that this satellite represents a novel species. Its closest relatives are in the genus Colecusatellite, but it likely represents a new genus given its divergence from other genera of the subfamily Geminialphasatellitinae. Given that WDV was the only virus observed in coinfection with the satellite, the name "wheat dwarf virus-associated alphasatellite" is proposed for this novel agent.

Genetic diversity and population structure of the Asian citrus psyllid in China.

The Asian citrus psyllid (ACP) is the main vector of Citrus Huanglongbing, the most damaging citrus disease, causing significant financial losses in the citrus industry. Global warming has expanded the habitat of this pest, allowing it to continue its northward migration to China. Population genetic information of ACP is fundamentally essential for species management. This study investigated the genetic diversity and population structure of Chinese ACP using the mitochondrial cytochrome oxidase subunit I gene by dataset comprised 721 sequences from 27 geographic sites in China. Low haplotype diversity (0.323 ±â€…0.022) and low nucleotide diversity (0.00071 ±â€…0.00007) were observed in the entire population, which may indicate recent founder events. Twenty-three haplotypes were identified and clustered into 2 haplogroups: haplogroup I and haplogroup II. Haplogroup II included only 2 unique haplotypes, which occurred exclusively in the Southwest China ACP population. Genetic differentiation analyses were also indicative of Southwest China population was significantly differentiated from the remaining populations. Demographic history analysis showed that ACP population in China has experienced demographic expansion. Our results provided a better understanding of the genetic distribution patterns and structures of ACP populations in China.

Simple dual-readout immunosensor based on phosphate-triggered and potassium permanganate for visual detection of fenitrothion.

Multicolor-based visual immunosensor is a promising tool for rapid analysis without the use of bulky instruments. Herein, an anti-fenitrothion nanobody-alkaline phosphatase fusion protein (VHHjd8-ALP) was employed to develop a multicolor visual immunosensor (MVIS) and a ratiometric fluorescence MVIS (RFMVIS, respectively). After one-step competitive immunoassay, the VHHjd8-ALP bound to microplate catalyzed phenyl phosphate disodium salt (ArP) into phenol. Under high alkaline condition (pH 12), the phenol reduced KMnO4 to intermediate (K2MnO4) and further to MnO2 in alkaline condition (pH 12), accompanied by a visible color transition of purple-green-yellow, which can be used for semiquantitative visual analysis or qualitative detection by measuring RGB value. RFMVIS was proposed on the basis of MVIS to further improve sensitivity. The CdTe quantum dot and fluorescein were used as signal probes to develop the fluorescent immunosensor. The CdTe dots with red emission (644 nm) was quenched by oxidation of KMnO4, whereas the fluorescein with green emission (520 nm) remained constant, accompanied by a fluorescent color transition of green-yellow-red. By measuring the ratio of the fluorescence intensity (I644/I520), the ratiometric fluorescence immunosensor was developed for qualitative analysis. The two visual immunosensors were sensitive and simple, and they showed good accuracy and practicability in the recovery test, thus are ideal tools for rapid screening.

Effective Platform Heating for Laser Powder Bed Fusion of an Al-Mn-Sc-Based Alloy.

Platform heating is one of the effective strategies used in laser powder bed fusion (LPBF) to avoid cracking during manufacturing, especially when building relatively large-size components, as it removes significant process-induced residual strains. In this work, we propose a novel and simple method to spare the elaborate post-processing heat treatment typically needed for LPBF Al-Sc alloys without compromising the mechanical properties. We systematically investigated the effects of LPBF platform heating at 200 °C on the residual stress relief, microstructure, and mechanical performance of a high-strength Al-Mn-Sc alloy. The results reveal that LPBF platform heating at 200 °C is sufficient to largely relieve the process-induced residual stresses compared to parts built on an unheated 35 °C platform. Meanwhile, the platform heating triggered the dynamic precipitation of uniformly dispersed (1.5-2 nm) Sc-rich nano-clusters. Their formation in a high number density (1.75 × 1024 m-3) resulted in a ~20% improvement in tensile yield strength (522 MPa) compared to the build on the unheated platform, without sacrificing the ductility (up to 18%). The improved mechanical properties imply that platform heating at 200 °C can strengthen the LPBF-synthesised Sc-containing Al alloys via in situ aging, which is further justified by an in situ measurement study revealing that the developing temperatures in the LPBF part are within the aging temperature range of Al-Sc alloys. Without any post-LPBF treatments, these mechanical properties have proven better than those of most Al-Sc alloys through long-time post-LPBF heat treatment.

Interaction between the flagellum of Candidatus Liberibacter asiaticus and the vitellogenin-like protein of Diaphorina citri significantly influences CLas titer.

Huanglongbing (HLB) is a global devastating citrus disease that is mainly caused by "Candidatus Liberibacter asiaticus" (CLas). It is mostly transmitted by the insect Asian citrus psyllid (ACP, Diaphorina citri) in a persistent and proliferative manner. CLas traverses multiple barriers to complete an infection cycle and is likely involved in multiple interactions with D. citri. However, the protein-protein interactions between CLas and D. citri are largely unknown. Here, we report on a vitellogenin-like protein (Vg_VWD) in D. citri that interacts with a CLas flagellum (flaA) protein. We found that Vg_VWD was upregulated in CLas-infected D. citri. Silencing of Vg_VWD in D. citri via RNAi silencing significantly increased the CLas titer, suggesting that Vg_VWD plays an important role in the CLas-D. citri interaction. Agrobacterium-mediated transient expression assays indicated that Vg_VWD inhibits BAX- and INF1-triggered necrosis and suppresses the callose deposition induced by flaA in Nicotiana benthamiana. These findings provide new insights into the molecular interaction between CLas and D. citri.

Ultrastrong nanotwinned titanium alloys through additive manufacturing.

Titanium alloys, widely used in the aerospace, automotive and energy sectors, require complex casting and thermomechanical processing to achieve the high strengths required for load-bearing applications. Here we reveal that additive manufacturing can exploit thermal cycling and rapid solidification to create ultrastrong and thermally stable titanium alloys, which may be directly implemented in service. As demonstrated in a commercial titanium alloy, after simple post-heat treatment, adequate elongation and tensile strengths over 1,600 MPa are achieved. The excellent properties are attributed to the unusual formation of dense, stable and internally twinned nanoprecipitates, which are rarely observed in traditionally processed titanium alloys. These nanotwinned precipitates are shown to originate from a high density of dislocations with a dominant screw character and formed from the additive manufacturing process. The work here paves the way to fabricate structural materials with unique microstructures and excellent properties for broad applications.

Transition Metal Doping Induces Ti3+ to Promote the Performance of SrTiO3 @TiO2 Visible Light Photocatalytic Reduction of CO2 to Prepare C1 Product.

Transition metal Fe, Co, Ni and Cu doped strontium titanate-rich SrTiO3 @TiO2 (STO@T) materials were prepared by hydrothermal method. The prepared doped materials exhibit better photocatalytic CO2 reduction to CH4 ability under visible light conditions. Among them, Fe-doped and undoped SrTiO3 @TiO2 under visible light conditions CO2 reduction products only CO, while M-STO@T (M=Co, Ni, Cu) samples converted CO2 to CH4 . The average methane yield of Ni-doped STO@T samples are as high as 73.85 µmol g-1 h-1 . The production of methane is mainly due to the increase in the response of the doped samples to visible light. And the increase in the separation rate of photogenerated electrons and holes and the efficiency of electron transport caused by the generation of impurity levels. The impurity level caused by Ti3+ plays an important role in the production of methane by CO2 visible light reduction. Ni doping effectively improves the photocatalytic performance of STO@T and CO2 reduction mechanism were explained.

Field-Deployable Candidatus Liberibacter asiaticus Detection Using Recombinase Polymerase Amplification Combined with CRISPR-Cas12a.

The early detection of Candidatus Liberibacter asiaticus (CLas) by citrus growers facilitates early intervention and prevents the spread of disease. A simple method for rapid and portable Huanglongbing (HLB) diagnosis is presented here that combines recombinase polymerase amplification and a fluorescent reporter utilizing the nuclease activity of the clustered regularly interspaced short palindromic repeats/CRISPR-associated 12a (CRISPR-Cas12a) system. The sensitivity of this technique is much higher than PCR. Furthermore, this method showed similar results to qPCR when leaf samples were used. Compared with conventional CLas detection methods, the detection method presented here can be completed in 90 min and works in an isothermal condition that does not require the use of PCR machines. In addition, the results can be visualized through a handheld fluorescent detection device in the field.

Genome-Wide Identification and Characterization of the AlkB Gene Family in Sweet Orange (Citrus sinensis).

Sweet orange (Citrus sinensis) is a sub-tropical fruit crop with important economic value that is popular worldwide; however, various pathogens significantly affect citrus cultivation and distribution. AlkB homolog (ALKBH) proteins play crucial roles in RNA metabolism and translation in plants; however, no systematic investigations have been performed on ALKBH in sweet oranges. In this study, ten ALKBH gene family members were identified in Citrus sinensis genome. Standardized analyses, including physical properties, phylogenetic analysis, gene structure, motif composition, cis-acting element prediction, chromosome distribution, and synteny analysis, were conducted. The phylogenetic analysis suggested that the ten proteins were clustered into three groups, each of which had similar motifs and gene structures. Gene expression profiling revealed that almost all CsALKBH proteins were highly expressed in callus, and ALKBH9/10-like group members responded positively to biotic stress. Overall, this study is the first to report a genome-wide assessment of the ALKBH family in sweet oranges and provides valuable insights for candidate gene selection and elucidating the molecular mechanism of sweet orange response to pathogenic infections.

[Development of practical liberal courses for students with non-biology majors under the "Double First-class" background].

Life sciences are the disciplines most closely related with human beings. As experimental disciplines, life sciences develop rapidly and highly intersect in many scientific fields. Under the "double first-class" initiative, the comprehensive development-oriented talent training system has put forward an urgent need for life sciences literacy and comprehensive ability training of college students. Taking the reform of liberal education curriculum system as an opportunity, we developed a series of eight life sciences practical liberal courses for students with non-biology majors. The courses cover all sub-disciplines or directions of life sciences, and aim to foster interdisciplinary talents with life sciences knowledge and literacy, as well as practical and innovative abilities. These courses could serve as references for experimental teaching centers in colleges and universities to set up practical liberal and experimental courses.

Characterization and phylogenetic analysis of the complete mitochondrial genome of Pseudothemis zonata (Odonata: Anisoptera: Libellulidae).

Pseudothemis zonata is a commonly seen dragonfly with a big yellow or white ringlike spot on the third and fourth segments of its abdomen. In this study, we sequenced and analyzed the complete mitochondrial genome (mitogenome) of P. zonata. This mitogenome was 15,434 bp long and encoded 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and 2 ribosomal RNA unit genes (rRNAs). Gene order was conserved and identical to most other previously sequenced Libellulidae dragonflies. The whole mitogenome exhibited heavy AT nucleotide bias (74.6%). Most PCGs of P. zonata have the conventional start codons ATN (six ATG, three ATT, and two ATC), with the exception of cox1 and nad1 (TTG). Except for four genes (cox1, cox2, cox3, and nad5) end with the incomplete stop codon T-, all other PCGs terminated with the stop codon TAA or TAG. Phylogenetic analysis showed that P. zonata got together with Brachythemis contaminata with high support value, and the relationships ((Brachythemis + Psolodesmus) + ((Hydrobasileus + Trigomphus) + (Orthetrum + Acisoma))) were supported in Libellulidae.

Long noncoding RNA KCNQ1OT1 contributes to tumor growth and activates Wnt/ß­catenin signaling in osteosarcoma by targeting the miR­3666/KLF7 axis.

Osteosarcoma (OS) is a type of primary malignant cancer occurring in the bone and poses a threat to the lives of children and young adults. Long non­coding RNAs (lncRNAs) have been certified to play important roles in various human malignant tumors, including OS. lncRNA KCNQ1OT1 has been investigated in certain types of cancer; however, its role and molecular mechanisms in OS remain to be determined. In the present study, a high KCNQ1OT1 expression was detected in human OS tissues and cell lines. Moreover, patients with OS with a high expression of KCNQ1OT1 presented a worse prognosis. Loss­of­function assays demonstrated that KCNQ1OT1 silencing suppressed cell proliferative, migratory and invasive abilities in OS. Importantly, the knockdown of KCNQ1OT1 suppressed the Wnt/ß­catenin signaling pathway in OS. In vivo assays displayed the inhibitory role of the silencing of KCNQ1OT1 in OS tumor growth. As regards the underlying mechanisms, KCNQ1OT1 could sponge miR­3666, and its expression was negatively associated with that of miR­3666 in OS tissues. Thereafter, Kruppel­like factor 7 (KLF7), upregulated in OS tissues and cells, was discerned as a target gene of miR­3666. Furthermore, KLF7 expression negatively correlated with miR­3666 expression, whereas it positively correlated with KCNQ1OT1 expression. A rescue assay delineated that the overexpression of KLF7 counteracted the KCNQ1OT1 knockdown­induced suppression of OS cell proliferation, migration, invasion and Wnt/ß­catenin signaling. Collectively, the present study demonstrates that KCNQ1OT1 facilitates OS progression and activates Wnt/ß­catenin signaling by targeting the miR­3666/KLF7 axis.

Complete mitochondrial genome sequence of Anax parthenope (Odonata: Anisoptera: Aeshnidae) and phylogenetic analysis.

Anax parthenope (Odonata: Aeshnidae) is a big dragonfly which can be seen patrolling around ponds, lakes and other still water. In this study, we sequenced and analyzed the complete mitochondrial genome (mitogenome) of A. parthenope. This mitogenome was 15,366 bp long and encoded 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs) and two ribosomal RNA unit genes (rRNAs). The nucleotide composition of the mitogenome was biased toward A and T, with 74.8% of A + T content (A 40.1%, T 34.7%, C 14.0%, G 11.2%). Gene order was conserved and identical to most other previously sequenced Aeshnidae dragonflies. Most PCGs of A. parthenope have the conventional start codons ATN (six ATG, three ATT, and two ATC), with the exception of cox1 and nad1 (TTG). Except for three genes (cox1, cox2, and nad5) end with the incomplete stop codon T--, all other PCGs terminated with the stop codon TAA. Phylogenetic analysis showed that A. parthenope is sister to Anax imperator with high support value. All 15 Anisoptera species constituted a major clade with well support, and Aeshnidae had a close relationship with Gomphidae and Libellulidae.

Natural Defect of a Plant Rhabdovirus Glycoprotein Gene: A Case Study of Virus-Plant Coevolution.

Seven isolates of a putative cytorhabdovirus (family Rhabdoviridae, order Mononegavirales) designated as citrus-associated rhabdovirus (CiaRV) were identified in citrus, passion fruit, and paper bush from the same geographical area in China. CiaRV, bean-associated cytorhabdovirus (Brazil), and papaya virus E (Ecuador) should be taxonomically classified in the species Papaya cytorhabdovirus. Due to natural mutations, the glycoprotein (G) and P4 genes were impaired in citrus-infecting isolates of CiaRV, resulting in an atypical rhabdovirus genome organization of 3' leader-N-P-P3-M-L-5' trailer. The P3 protein of CiaRV shared a common origin with begomoviral movement proteins (family Geminiviridae). Secondary structure analysis and trans-complementation of movement-deficient tomato mosaic virus and potato virus X mutants by CiaRV P3 supported its function in viral cell-to-cell trafficking. The wide geographical dispersal of CiaRV and related viruses suggests an efficient transmission mechanism, as well as an underlying risk to global agriculture. Both the natural phenomenon and experimental analyses demonstrated presence of the "degraded" type of CiaRV in citrus, in parallel to "undegraded" types in other host plant species. This case study shows a plant virus losing the function of an important but nonessential gene, likely due to host shift and adaption, which deepened our understanding of course of natural viral diversification.

The Analysis of Differentially Expressed circRNAs Under the Antiproliferative Effect From 5-Fluorouracil on Osteosarcoma Cells.

BACKGROUND: 5-fluorouracil (5-FU) is a widely used drug for cancer treatment, but its effect and underlying mechanisms on osteosarcoma (OS) cells remain unclear. METHODS: U2OS and MG63 cells were treated with 0, 50, 100, and 500 µM 5-FU. MTS and flow cytometry were used to examine the effect of 5-FU on cell viability and apoptosis, respectively. Circular RNA (circRNA) expression was detected using RNA sequencing and quantitative real-time PCR (qPCR). Differentially expressed circRNAs were further subjected to the Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) analysis to predict their functions. A circRNA-miRNA-mRNA interaction network was generated to analyze the regulatory networks of 5-FU-induced differentially expressed circRNAs. Western blotting (WB) was used to verify the protein in the downstream of circRNAs. RESULTS: 5-FU inhibited the cell viability of the MG63 cells in a concentration-dependent manner. The most significant effect was observed in the cells treated with 500 µM 5-FU. Apoptosis was also increased in the MG63 cells after 500 µM 5-FU treatment for 3 days. RNA sequencing results showed that 183 differentially expressed circRNAs (172 upregulated and 11 downregulated) in 5-FU-treated cells. KEGG and GO analysis showed that the differentially expressed circRNAs were primarily enriched in proliferation-, apoptosis-, and metabolism-related functions. qPCR was used to verify the most upregulated and downregulated circRNAs. The circRNA-miRNA-mRNA interaction network showed that these 8 circRNAs had a sizable regulatory network that links a series of genes involved in tumor suppression. CONCLUSION: 5-FU treatment resulted in the differentially expressed circRNAs that were proliferation- and apoptosis-associated and were involved in the 5-FU-induced inhibition of tumor proliferation in OS cells.

Longitudinal anti-SARS-CoV-2 antibody profile and neutralization activity of a COVID-19 patient.

We followed-up a mild COVID-19 patient for 91 days and serially monitored his serum antibodies to four SARS-CoV-2 related antigens (NP, RBD, S1 and ECD) and neutralization activities. Our data revealed a profile of serial antibody responses during the progress and a quick decline of neutralization activities after discharge.

High SARS-CoV-2 antibody prevalence among healthcare workers exposed to COVID-19 patients.

The seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was examined among 105 healthcare workers (HCWs) exposed to four patients who were laboratory confirmed with coronavirus disease 2019 (COVID-19), the disease caused by SARS-CoV-2 infection. These HCWs were immediately under quarantine for 14 days as soon as they were identified as close contacts. The nasopharyngeal swab samples were collected on the first and 14th day of the quarantine, while the serum samples were obtained on the 14th day of the quarantine. With the assay of enzyme immunoassay (EIA) and microneutralization assay, 17.14% (18/105) of HCWs were seropositive, while their swab samples were found to be SARS-CoV-2 RNA negative. Risk analysis revealed that wearing face mask could reduce the infection risk (odds ratio [OR], 0.127, 95% confidence interval [CI] 0.017, 0.968), while when exposed to COVID-19 patients, doctors might have higher risk of seroconversion (OR, 346.837, 95% CI 8.924, 13479.434), compared with HCWs exposed to colleagues as well as nurses and general service assistants who exposed to patients. Our study revealed that the serological testing is useful for the identification of asymptomatic or subclinical infection of SARS-CoV-2 among close contacts with COVID-19 patients.

Portioning-Out and Individuation in Mandarin Non-interrogative wh-Pronominal Phrases: Experimental Evidence From Child Mandarin.

Portioning-out and individuation are two important semantic properties for the characterization of countability. In Mandarin, nouns are not marked with count-mass syntax, and it is controversial whether individuation is encoded in classifiers or in nouns. In the present study, we investigates the interpretation of a minimal pair of non-interrogative wh-pronominal phrases, including duo-shao-N and duo-shao-ge-N. Due to the presence/absence of the individual classifier ge, these two wh-pronominal phrases differ in how they encode portioning-out and individuation. In two experiments, we used a Truth Value Judgment Task to examine the interpretation of these two wh-pronominal phrases by Mandarin-speaking adults and 4-to-6-year-old children. We found that both adults and children are sensitive to their interpretative differences with respect to the portioning-out and individuation properties. They assign either count or mass readings to the bare wh-pronominal phrase duo-shao-N depending on specific contexts, but only count readings to the classifier-bearing wh-pronominal phrase duo-shao-ge-N. Moreover, the portioning-out and individuation properties associated with the individual classifier ge emerge independently in the course of language development, with the portioning-out property taking precedence over the individuation property. Taken together, the present study provides new evidence for the view that the portioning-out and individuation properties in Mandarin are encoded in classifiers rather than in nouns, and these two semantic properties are two distinct components in our grammar.

Hot Deformation Behavior of a New Al-Mn-Sc Alloy.

The hot deformation behavior of a new Al-Mn-Sc alloy was investigated by hot compression conducted at temperatures from 330 to 490 °C and strain rates from 0.01 to 10 s-1. The hot deformation behavior and microstructure of the alloy were significantly affected by the deformation temperatures and strain rates. The peak flow stress decreased with increasing deformation temperatures and decreasing strain rates. According to the hot deformation behavior, the constitutive equation was established to describe the steady flow stress, and a hot processing map at 0.4 strain was obtained based on the dynamic material model and the Prasad instability standard, which can be used to evaluate the hot workability of the alloy. The developed hot processing diagram showed that the instability was more likely to occur in the higher Zener-Hollomon parameter region, and the optimal processing range was determined as 420-475 °C and 0.01-0.022 s-1, in which a stable flow and a higher power dissipation were achieved.

Silencing of the Chitin Synthase Gene Is Lethal to the Asian Citrus Psyllid, Diaphorina citri.

Chitin synthase is a critical enzyme that catalyzes N-acetylglucosamine to form chitin, which plays an important role in the growth and development of insects. In this study, we identified a chitin synthase gene (CHS) with a complete open reading frame (ORF) of 3180 bp from the genome database of Diaphorina citri, encoding a protein of 1059 amino acid residues with the appropriate signature motifs (EDR and QRRRW). Reverse transcription-quantitative PCR (RT-qPCR) analysis suggested that D. citri CHS (DcCHS) was expressed throughout all developmental stages and all tissues. DcCHS had the highest expression level in the integument and fifth-instar nymph stage. Furthermore, the effects of diflubenzuron (DFB) on D. citri mortality and DcCHS expression level were investigated using fifth-instar nymph through leaf dip bioassay, and the results revealed that the nymph exposed to DFB had the highest mortality compared with control group (Triton-100). Silencing of DcCHS by RNA interference resulted in malformed phenotypes and increased mortality with decreased molting rate. In addition, transmission electron microscopy (TEM) and fluorescence in situ hybridization (FISH) also revealed corresponding ultrastructural defects. Our results suggest that DcCHS might play an important role in the development of D. citri and can be used as a potential target for psyllid control.