Biology subjects

Ji, X.

Publications and source records attributed to Ji, X..

At least 91 records · Page 5Linked to original sources

bioRxiv2022

Revealing the molecular mechanisms underlying neural transmission of female pheromone signals in the male antennae of Antheraea pernyi by integrative proteomics and metabolomics analysis

Detection of sex pheromones of insects relies on the antennae. The female pheromone signal transmission in the male antennae ultimately initiates the courtship and mating behaviors of males. To investigate the proteins and metabolites involved in this neural transduction, the study adopted integrative proteomics and metabolomics analysis including tandem mass tag (TMT) proteomic quantification and liquid chromatography tandem mass spectrometry (LC/MS)-based metabolomics for comparing proteomic and metabolic changes between the antennae of male moths following stimulation by females and the non-stimulated males of A. pernyi. A total of 92 differentially expressed proteins (DEPs) containing 52 up-regulated and 40 down-regulated proteins and 545 differentially expressed metabolites (DEMs) including 218 up- and 327 down-regulated metabolites were identified from the antennae of female-stimulated male moths based on the proteome and metabolome data, respectively. GO enrichment analysis showed that 45 DEPs could be enriched into different GO terms on different levels. COG analysis indicated that 61 DEPs were assigned to 20 functional categories. The 160 DEMs respectively fell into 11 and 44 classes at SuperClass and Class levels based on HMDB annotation. KEGG pathway enrichment analysis indicated that totally 43 DEMs were enriched into 6, 27, and 87 pathways on level 1, 2, and 3, respectively. A number of DEPs and DEMs related to neural transmission of female pheromone signals in the male antennae of A. pernyi were screened, including tyrosine hydroxylase, cryptochrome-1, tachykinin, arylalkylamine N-acetyltransferase, cadherin-23, glutathione S-transferase delta 3, tyramine, tryptamine, n-oleoyl dopamine, n-stearoyl dopamine, and n-stearoyl tyrosine. We concluded that the altered expression levels of those proteins or metabolites were involved in regulating the neuron activity for enhanced transmission of neural impulses and continuous perception, reception, and transduction of female pheromone signals. Our findings yielded novel insights into the potential molecular mechanisms in the antennae of male A. pernyi responding to female attraction.

molecular biology↗

bioRxiv2022

A lone spike in blood glucose can enhance the thrombo-inflammatory response in cortical venules

How transient hyperglycemia contributes to cerebro-vascular disease has been a challenge to study under controlled conditions. We present an approach to model luminal vessel thrombo-inflammation using amplified, ultrashort laser-pulses to physically disrupt brain-venule endothelium. Vessel disruption in conjunction with transient hyperglycemia from a single injection of metabolically active D-glucose results in real-time responses to venule damage that include rapid serum extravasation, platelet aggregation, and neutrophil recruitment, in normal mice. In contrast, vessel thrombo-inflammation following laser-induced vessel disruption is significantly reduced in mice injected with metabolically inert L-glucose. Thrombo-inflammation is pharmacologically ameliorated by a platelet inhibitor, by a scavenger of reactive oxygen species, or by a nitric oxide donor. For comparison, in diabetic mice injured vessel thrombo-inflammatory responses are also reduced by restoration of normo-glycemia. Our approach provides a controlled method to probe synergies of transient metabolic and physical vascular perturbations and reveals new aspects of brain pathophysiology.

neuroscience↗

bioRxiv2022

Integrated Analysis of T cell Repertoire and Transcriptome Identifies Mechanisms of Regulatory T cell (Treg) Suppression of Acute Graft-versus-Host-Disease

CD4+FOXP3+ regulatory T cells have demonstrated efficacy in graft-versus-host disease (GvHD) prevention and treatment. Preclinical and clinical studies indicate that Treg are able to protect from GvHD without interfering with the graft-versus-tumor (GvT) effect of hematopoietic cell transplantation (HCT), although the underlying molecular mechanisms are largely unknown. To elucidate Treg suppressive function during in vivo suppression of acute GvHD, we performed paired T cell receptor (TCR, TCR{beta} genes) repertoire sequencing and RNA sequencing analysis on conventional T cells (Tcon) and Treg before and after transplantation in an MHC major-mismatch mouse model of HCT. We show that both Treg and Tcon underwent clonal restriction and that Treg did not interfere with the activation of alloreactive Tcon clones and the breadth of their TCR repertoire, however, markedly suppressed their expansion. Transcriptomic analysis revealed that Treg predominantly affected the transcriptome of CD4 Tcon and to a lesser extent of CD8 Tcon, modulating the transcription of genes encoding pro- and anti-inflammatory molecules as well as enzymes involved in metabolic processes, inducing a switch from glycolysis to oxidative phosphorylation. Finally, Treg did not interfere with the induction of gene sets involved in the GvT effect. Our results shed light into the mechanisms of acute GvHD suppression by Treg and will support the clinical translation of this immunoregulatory approach. Key Points- Regulatory T cells modulate conventional T cells transcriptome during GvHD suppression by affecting several, non-redundant pathways. - Regulatory T cells undergo activation and clonal expansion during GvHD suppression.

immunology↗

bioRxiv2022

Organic Electrochemical Transistor as an On-site Signal Amplifier for Electrochemical Aptamer-based Sensing

Electrochemical aptamer-based (E-AB) sensors are typically deployed as individual, passive, surface-functionalized electrodes, but they exhibit limited sensitivity especially when the area of the electrode is reduced for miniaturization purposes. We demonstrated that organic electrochemical transistors (OECTs), electrolyte gated tran-istors with volumetric gating, can serve as on-site amplifiers to improve the sensitivity of single electrode-based E-AB sensors. By monolithically integrating an Au working/sensing electrode, on-chip Ag/AgCl reference electrode and Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) counter electrode -- also serving as the OECT channel, we can simultaneously perform OECT testing and traditional electroanalytical measurement on E-AB sensors including cyclic voltammetry (CV) and square-wave voltammetry (SWV). This device can directly amplify the current from the E-AB sensor via the in-plane current modulation in the counter electrode/transistor channel. The integrated OECT-based E-AB sensor is able to sense transforming growth factor beta 1 (TGF-{beta}1) with 3 to 4 orders of magnitude enhancement of sensitivity compared to that in a single electrode-based E-AB sensor (292 {micro}A/dec vs. 85 nA/dec for OECT vs. single electrode SWV). This approach is believed to be universal, which can be applied to a wide range of tethered electrochemical reporter-based sensors to enhance sensitivity, aiding in sensor miniaturization and easing the burden on backend signal processing.

bioengineering↗

bioRxiv2022

Triangulation fails when neither linguistic, genetic, nor archaeological data support the Transeurasian narrative

Robbeets et al.1 argue that the dispersal of the so-called "Transeurasian" languages, a highly disputed language superfamily comprising the Turkic, Mongolian, Tungusic, Koreanic, and Japonic language families, was driven by Neolithic farmers in the West Liao River region of China. They adduce evidence from linguistics, archaeology, and genetics to support their claim. An admirable feature of the Robbeets et al.s paper is that all their datasets can be accessed. However, a closer investigation of all three types of evidence reveals fundamental problems with each of them. Robbeets et al.s analysis of the linguistic data does not conform to the minimal standards required by traditional scholarship in historical linguistics and contradicts their own stated sound correspondence principles. A reanalysis of the genetic data finds that they do not conclusively support the farming-driven dispersal of Turkic, Mongolian, and Tungusic, nor the two-wave spread of farming to Korea. Their archaeological data contain little phylogenetic signal, and we failed to reproduce the results supporting their core hypotheses about migrations. Given the severe problems we identify in all three parts of the "triangulation" process, we conclude that there is neither conclusive evidence for a Transeurasian language family nor for associating the five different language families with the spread of Neolithic farmers from the West Liao River region.

genetics↗

bioRxiv2022

A cocktail containing two synergetic antibodies broadly neutralizes SARS-CoV-2 and its variants including Omicron BA.1 and BA.2

Neutralizing antibodies (NAbs) can prevent and treat infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, continuously emerging variants, such as Omicron, have significantly reduced the potency of most known NAbs. The selection of NAbs with broad neutralizing activities and the identification of conserved critical epitopes are still urgently needed. Here, we identified an extremely potent antibody (55A8) by single B-cell sorting from convalescent SARS-CoV-2-infected patients that recognized the receptor-binding domain (RBD) in the SARS-CoV-2 spike (S) protein. 55A8 could bind to wild-type SARS-CoV-2, Omicron BA.1 and Omicron BA.2 simultaneously with 58G6, a NAb previously identified by our group. Importantly, an antibody cocktail containing 55A8 and 58G6 (2-cocktail) showed synergetic neutralizing activity with a half-maximal inhibitory concentration (IC50) in the picomolar range in vitro and prophylactic efficacy in hamsters challenged with Omicron (BA.1) through intranasal delivery at an extraordinarily low dosage (25 g of each antibody daily) at 3 days post-infection. Structural analysis by cryo-electron microscopy (cryo-EM) revealed that 55A8 is a Class III NAb that recognizes a highly conserved epitope. It could block angiotensin-converting enzyme 2 (ACE2) binding to the RBD in the S protein trimer via steric hindrance. The epitopes in the RBD recognized by 55A8 and 58G6 were found to be different and complementary, which could explain the synergetic mechanism of these two NAbs. Our findings not only provide a potential antibody cocktail for clinical use against infection with current SARS-CoV-2 strains and future variants but also identify critical epitope information for the development of better antiviral agents.

immunology↗

bioRxiv2022

The addition of antibiotics to embryo culture media caused altered expression of genes in pathways governing DNA integrity in mouse blastocysts

Antibiotics are common components of embryo culture media and minimize the risk of microbial contamination and infection during assisted reproductive technology procedures (ART). The effects of two aminoglycoside antibiotics (gentamicin, streptomycin) and penicillin on the global profiles of gene expression (DE) were assessed by RNA-seq of individual mouse blastocysts. Zygotes were cultured in an optimized defined medium formulation (KSOM) to which a dose range of each antibiotic was added. A dose-dependent retardation of the rate of zygote development to morphologically normal blastocyst was observed and this was accompanied by a reduction in the number of cells present within the resulting blastocysts. The lowest dose of each antibiotic tested (similar to the concentrations used in clinical grade media) caused significant differential expression of approximately 1800 genes. In most cases antibiotic treatment caused a reduction in gene expression and gene ontology analysis showed that down regulated genes were enriched for several biological processes related to the maintenance of genomic integrity. All three antibiotics caused the downregulation of Brca2, Blm, Rad51c and Rad54l, genes involved DNA homologous recombination pathways and also several p53-dependent genes. Immunolocalization studies showed that each antibiotic also reduced level of BRCA2 and RAD51C detected within blastocysts. The present study shows that the supplementing embryo culture media with antibiotics is associated with wide ranging alterations in gene expression in a manner that could potentially compromise the genomic integrity of the resulting embryos.

developmental biology↗

bioRxiv2022

Deciphering of Somatic Mutational Signatures of Cancer

Somatic mutational signatures (MSs) identified by genome sequencing play important roles in exploring the cause and development of cancer. Thus far, many such signatures have been identified, and some of them do imply causes of cancer. However, a major bottleneck is that we do not know the potential meanings (i.e., cancer causal or biological functions) and contributing genes for most of them. Here we presented a computational framework, Gene Somatic Genome Pattern (GSGP), which can decipher the molecular mechanisms of the MSs. More importantly, it is the first time, GSGP is able to process MSs from RNA sequencing, which greatly extended the applications of both MS analysis and RNA sequencing. As a result, GSGP analysis matches consistently with previous reports and identify the aetiologies for a number of novel signatures. Notably, we applied GSGP to RNA sequencing data and revealed an RNA-derived MS involved in deficient DNA mismatch repair (dMMR) and microsatellite instability (MSI) in colorectal cancer (CRC).

genomics↗

bioRxiv2022

Metabolome and transcriptome analysis reveal components regulating soapberry triterpenoid saponin biosynthesis

Soapberry (Sapindus mukorossi Gaertn.) pericarps are rich in valuable bioactive triterpenoid saponins. However, the saponin content dynamics and the molecular regulatory network of saponin biosynthesis in soapberry pericarps remain largely unclear. Here, we performed combined metabolite profiling and transcriptome analysis to identify saponin accumulation kinetic patterns, investigate gene networks, and characterize key candidate genes and transcription factors involved in saponin biosynthesis in soapberry pericarps. A total of 54 saponins were tentatively identified, including 25 that were differentially accumulated. Furthermore, 49 genes putatively involved in sapogenin backbone biosynthesis and some candidate genes assumed to be responsible for the backbone modification, including 41 cytochrome P450s and 45 glycosyltransferases, were identified. Saponin-specific clusters/modules were identified by Mfuzz clustering and weighted gene co-expression network analysis, and one TF-gene regulatory network underlying saponin biosynthesis was proposed. The results of yeast one-hybrid assay and electrophoretic mobility shift assay suggested that SmbHLH2, SmTCP4, and SmWRKY27 may play important roles in the triterpenoid saponin biosynthesis by directly regulating the transcription of SmCYP71D-3 in soapberry pericarp. Overall, these findings provide valuable information for understanding the molecular regulatory mechanism of saponin biosynthesis, enriching the gene resources, and guiding further research on triterpenoid saponin accumulation in soapberry pericarps. One-sentence summaryCombining metabolome and transcriptome analysis to identify saponin kinetic patterns, gene networks, and key candidate genes and transcription factors involved in saponin biosynthesis of soapberry.

molecular biology↗

bioRxiv2022

scAnnotate: an automated cell type annotation tool for single-cell RNA-sequencing data

MotivationSingle-cell RNA-sequencing (scRNA-seq) technology enables researchers to investigate a genome at the cellular level with unprecedented resolution. An organism consists of a heterogeneous collection of cell types, each of which plays a distinct role in various biological processes. Hence, the first step of scRNA-seq data analysis is often to distinguish cell types so they can be investigated separately. Researchers have recently developed several automated cell type annotation tools, requiring neither biological knowledge nor subjective human decisions. Dropout is a crucial characteristic of scRNA-seq data widely used in differential expression analysis. However, dropout information is not explicitly used by any current cell annotation method. Fully utilizing dropout information for cell type annotation motivated this work. ResultsWe present scAnnotate, a cell annotation tool that fully utilizes dropout information. We model every genes marginal distribution using a mixture model, which describes both the dropout proportion and the distribution of the non-dropout expression levels. Then, using an ensemble machine learning approach, we combine the mixture models of all genes into a single model for cell-type annotation. This combining approach can avoid estimating numerous parameters in the high-dimensional joint distribution of all genes. Using fourteen real scRNA-seq datasets, we demonstrate that scAnnotate is competitive against nine existing annotation methods. Furthermore, because of its distinct modelling strategy, scAnnotates misclassified cells are very different from competitor methods. This suggests using scAnnotate together with other methods could further improve annotation accuracy. AvailabilityWe implemented scAnnotate as an R package and made it publicly available from CRAN. ContactXuekui Zhang: xuekui@uvic.ca and Li Xing: li.xing@math.usask.ca

bioinformatics↗

bioRxiv2022

Gut Microbiome Contributes to Cold-climate Adaptation in Lizards

The metabolic cold-climate adaption hypothesis predicts that animals from cold environments have relatively high metabolic rates compared with their warm-climate counterparts. However, studies testing this hypothesis are sparse. Here, we compared gut microbes between two cold-climate lizard species of the genus Phrynocephalus to test the hypothesis that gut microbiota can help lizards adapt to cold environments by promoting metabolism and absorption efficiency. We kept lizards at 24{degrees}C and 30{degrees}C for 25 d, and then collected their fecal samples to analyze and compare the microbiota based on 16S rRNA gene sequencing technology. The gut microbiota was mainly composed of Proteobacteria, Firmicutes, Bacteroidetes, and Verrucomicrobia at the phylum level in both species (Proteobacteria > Firmicutes > Verrucomicrobiota in P. erythrurus, and Bacteroidota > Proteobacteria > Firmicutes in P. przewalskii). Further analysis revealed that the gut microbiota contributed to the hosts cold adaptation, but with differences in the relative abundance of these contributory bacteria between the two species. KEGG analysis revealed that the gut microbiota primarily played roles in metabolism, genetic information processing, cellular processes, and environmental information processing in both species. Furthermore, genes related to metabolism were more abundant in P. erythrurus at 24 {degrees}C than in other species x temperature combinations, indicating the role of gut microbiota in long-term cold-climate adaptation. Our finding that gut microbiome contributes to cold-climate adaptation in both species but more evidently in P. erythrurus using colder habitats than P. przewalskii throughout a year confirms the gut microbiotas role in the cold-climate adaptation in lizards. IMPORTANCEThis study proves that temperature affects the composition and relative abundance of the gut microbiota in two Phrynocephalus lizards in a species-specific manner. Both species harbor specific gut microbiota with significant roles in cold-climate adaptation. Specifically, P. erythrurus has a higher Proteobacteria ratio and relative abundance of metabolism-related microbial genes in the gut than P. przewalskii. Given that P. erythrurus uses colder habitats than P. przewalskii throughout a year, these results suggest that gut microbiota contributes to cold-climate adaptation in both species lizards but more evidently in P. erythrurus. This study provides evidence linking gut microbiome with cold adaptation. The co-evolution mechanism between gut microbiota and their hosts in extreme environments will provide new insights into animal adaptation.

ecology↗

bioRxiv2022

Glutamate indicators with improved activation kinetics and localization for imaging synaptic transmission

The fluorescent glutamate indicator iGluSnFR enables imaging of neurotransmission with genetic and molecular specificity. However, existing iGluSnFR variants exhibit saturating activation kinetics and are excluded from post-synaptic densities, limiting their ability to distinguish synaptic from extrasynaptic glutamate. Using a multi-assay screen in bacteria, soluble protein, and cultured neurons, we generated novel variants with improved kinetics and signal-to-noise ratios. We also developed surface display constructs that improve iGluSnFRs nanoscopic localization to post-synapses. The resulting indicator, iGluSnFR3, exhibits rapid non-saturating activation kinetics and reports synaptic glutamate release with improved linearity and increased specificity versus extrasynaptic signals in cultured neurons. In mouse visual cortex, imaging of iGluSnFR3 at individual boutons reported single electrophysiologically-observed action potentials with high specificity versus non-synaptic transients. In vibrissal sensory cortex Layer 4, we used iGluSnFR3 to characterize distinct patterns of touch-evoked feedforward input from thalamocortical boutons and both feedforward and recurrent input onto L4 cortical neuron dendritic spines.

neuroscience↗

bioRxiv2022

Lyophilized mRNA-lipid nanoparticles vaccine with long-term stability and high antigenicity against SARS-CoV-2

Advanced mRNA vaccines play vital roles against SARS-CoV-2. However, due to their poor stability, most current mRNA delivery platforms need to be stored at -20{degrees}C or -70{degrees}C, which severely limits their distribution. Herein, we present lyophilized SARS-CoV-2 mRNA-lipid nanoparticle vaccines, which can be stored at room temperature with long-term thermostability. In the in vivo Delta virus challenge experiment, lyophilized Delta variant mRNA vaccine successfully protected mice from infection and cleared the virus. Lyophilized omicron mRNA vaccine enabled to elicit both potent humoral and cellular immunity. In booster immunization experiments in mice and old monkeys, lyophilized omicron mRNA vaccine could effectively increase the titers of neutralizing antibodies against wild-type coronavirus and omicron variants. In humans, lyophilized omicron mRNA vaccine as a booster shot could also engender excellent immunity and had less severe adverse events. This lyophilization platform overcomes the instability of mRNA vaccines without affecting their bioactivity, and significantly improved their accessibility, particularly in remote regions.

immunology↗

bioRxiv2022

Research on the temporal evolution track and influence of green development in the last decade

Green development is important to realize the coordinated development of local ecological environment, economy and society, but also an important way to promote the harmony between human and land. This study utilizes projection pursuit model (PPM) measure, as well as the system gray prediction model GM (1, N), and other measurement methods, build an evaluation system from three dimensions of green fortune, green growth and green benefits to analyze the temporal evolution, development trend and its influencing factors of Baoshans ecological engineering of project acres, the results show: (1)The overall level of the green development system in Baoshan, Yunnan Province, is relatively good and shows an increasing trend year by year, with an average growth rate of 18.3%, and there is a synergistic coupling effect among the three subsystems. (2) Regional green development has achieved remarkable progress, but problems and pressure among the three subsystems are still grim. The sub-system of green growth and green benefits declined from 2010 to 2016, with an annual decline rate of 12%, and then picked up slightly in the next three years, reflecting the pressure of resources and ecological environment in this region and the difficulty of the sub-system of green wealth growth. (3) The prediction analysis shows that the green development index in Baoshan, Yunnan Province will keep a steady rise in the next two years, and the predicted value will be 4.51 in 2020, with an average growth rate of 15.1%, and the regional green development system is in good condition. (4) Green development is mainly affected by environmental pollution, industrial structure, urbanization, population, market and other factors from the three subsystems of local ecology, ecology, economy and social benefits. This paper puts forward suggestions in terms of popularizing the concept of green development, improving the level of ecological economic development and promoting the regional environment bearing capacity, green development model of ecological engineering area is also built. It aims to have some practical reference value for prompting regional ecological civilization construction and green development. And provide regional support for the post-2020 Global Biodiversity Framework and the Achievement of the United Nations Sustainable Development Goals.

ecology↗

bioRxiv2021

Human KIR+CD8+ T cells target pathogenic T cells in Celiac disease and are active in autoimmune diseases and COVID-19

Previous reports show that Ly49+CD8+ T cells can suppress autoimmunity in mouse models of autoimmune diseases. Here we find a markedly increased frequency of CD8+ T cells expressing inhibitory Killer cell Immunoglobulin like Receptors (KIR), the human equivalent of the Ly49 family, in the blood and inflamed tissues of various autoimmune diseases. Moreover, KIR+CD8+ T cells can efficiently eliminate pathogenic gliadin-specific CD4+ T cells from Celiac disease (CeD) patients leukocytes in vitro. Furthermore, we observe elevated levels of KIR+CD8+ T cells, but not CD4+ regulatory T cells, in COVID-19 and influenza-infected patients, and this correlates with disease severity and vasculitis in COVID-19. Expanded KIR+CD8+ T cells from these different diseases display shared phenotypes and similar T cell receptor sequences. These results characterize a regulatory CD8+ T cell subset in humans, broadly active in both autoimmune and infectious diseases, which we hypothesize functions to control self-reactive or otherwise pathogenic T cells. One-Sentence SummaryHere we identified KIR+CD8+ T cells as a regulatory CD8+ T cell subset in humans that suppresses self-reactive or otherwise pathogenic CD4+ T cells.

immunology↗

bioRxiv2021

A magnetic field prevents alcoholic liver disease by reducing oxidative stress

The radical-pair recombination change will affect the generation of free radicals, which can be regulated by static magnetic fields (SMFs) in a SMF setting dependent way. It is well known that alcohol consumption leads to significantly increased free radical levels and health risks, which lacks effective treatment method besides alcohol abstinence. Here we compared different SMF settings and found that a downward SMF of [~]0.1 T with magnetic flux of [~]4.5x10-3 Wb could effectively alleviate alcohol-induced liver damage and lipid accumulation, and improve liver function. The inflammation, reactive oxygen species (ROS) level and oxidative stress were significantly reduced. EPR (electron paramagnetic resonance) experiments also confirmed the reduced amount of free radical by SMF treatment. Moreover, the lifespan of heavy alcohol drinking mice was also significantly changed due to the SMF effects on liver cell ROS level, DNA synthesis and liver cell regeneration. Our study shows that moderate SMFs with specific parameters have great promises to be developed into a physical method to reduce alcohol-induced liver damage in the future.

physiology↗

bioRxiv2021

Total virome characterizations of game animals in China reveals a spectrum of emerging viral pathogens

Game animals are wildlife species often traded and consumed as exotic food, and are potential reservoirs for SARS-CoV and SARS-CoV-2. We performed a meta-transcriptomic analysis of 1725 game animals, representing 16 species and five mammalian orders, sampled across China. From this we identified 71 mammalian viruses, with 45 described for the first time. Eighteen viruses were considered as potentially high risk to humans and domestic animals. Civets (Paguma larvata) carried the highest number of potentially high risk viruses. We identified the transmission of Bat coronavirus HKU8 from a bat to a civet, as well as cross-species jumps of coronaviruses from bats to hedgehogs and from birds to porcupines. We similarly identified avian Influenza A virus H9N2 in civets and Asian badgers, with the latter displaying respiratory symptoms, as well as cases of likely human-to-wildlife virus transmission. These data highlight the importance of game animals as potential drivers of disease emergence. HighlightsO_LI1725 game animals from five mammalian orders were surveyed for viruses C_LIO_LI71 mammalian viruses were discovered, 18 with a potential risk to humans C_LIO_LICivets harbored the highest number of potential high risk viruses C_LIO_LIA species jump of an alphacoronavirus from bats to a civet was identified C_LIO_LIH9N2 influenza virus was detected in a civet and an Asian badger C_LIO_LIHumans viruses were also identified in game animals C_LI

zoology↗

bioRxiv2021

A MYB transcription factor, PlMYB308, plays an essential role in flower senescence of herbaceous peony

Herbaceous peony is an important cut-flower plant cultivated across the world, but its short vase life substantially restricts the economic value of this crop. It is well established that endogenous hormones regulate the senescing process, but the molecular mechanism of them in flower senescence is still unclear. Here, we isolated a MYB transcription factor gene PlMYB308 from herbaceous peony flowers. Transcript abundance of PlMYB308 was strongly up-regulated in senescing petals. Silencing of PlMYB308 resulted in delayed peony flower senescence, and dramatically increased gibberellin (GA) but reduced ethylene and abscisic acid (ABA) levels in petals. Ectopic overexpression of PlMYB308 in tobacco accelerated flower senescence, and reduced GA but increased ethylene and ABA accumulation. Correspondingly, biosynthetic genes of ethylene, ABA, and GA showed variable expression levels in petals after silencing or overexpression of PlMYB308. A dual-luciferase assay showed that PlMYB308 specifically bound to the PlACO1 promoter. High expression levels of PlMYB308 were accompanied by low petal anthocyanin accumulation in senescing petals. A further bimolecular fluorescence complementation assay revealed an interaction between PlMYB308 and PlbHLH33, which was supposed to inhibit the anthocyanin biosynthesis. Taken together, our results suggest that the PlMYB308-PlACO1 and PlMYB308-PlbHLH33 regulatory checkpoints perhaps positively and negatively operate the production of ethylene and anthocyanin, respectively, and thus contribute to the senescence with impaired pigmentation in herbaceous peony flowers.

biophysics↗