Publications by authors named "Zhixin Zhu"

14 Publications

  • Page 1 of 1

Multiple MYB Activators and Repressors Collaboratively Regulate the Juvenile Red Fading in Leaves of Sweetpotato.

Front Plant Sci 2020 25;11:941. Epub 2020 Jun 25.

Key Laboratory of Tropical Biological Resources, Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, Haikou, China.

Juvenile red fading describes the phenomenon in plants whereby red young leaves gradually turn green as they mature. While this phenomenon is commonly observed, the underlying molecular mechanism is still obscure as the classic model plants do not exhibit this process. Here, the molecular mechanism for the loss of anthocyanins during juvenile red fading were explored in the sweetpotato ( L.) cultivar "Chuanshan Zi". The MYB-bHLH-WDR (MBW) regulatory complexes for anthocyanins were examined with five stages of leaf development from C1 to C5. Alternating accumulation of anthocyanins and chlorophylls caused the leaf color change. Five anthocyanin components were identified by ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS), and their contents were highest at stage C2. Transcriptomic analysis showed massive gene expression alteration during leaf development. The anthocyanin structural genes expressed in sweetpotato leaves were screened and found to be highly comparable with those identified in morning glories. The screened anthocyanin regulatory genes included one bHLH (), one WDR (), three MYB activators (, and ), and five MYB repressors (, , , and ). The expression trends of MYBs were key to the red fading process: the activators were highly expressed in early red leaves and were all accompanied by simultaneously expressed MYB repressors, which may act to prevent excessive accumulation of anthocyanins. The only antagonistic repressor, , was highly expressed in green leaves, and may be critical for declined anthocyanin content at later stages. Further functional verification of the above transcription factors were conducted by promoter activation tests. These tests showed that the MBW complexes of IbMYB1/IbMYB2/IbMYB3-IbbHLH2-IbWDR1 not only activated promoters of anthocyanin structural genes and , but also promoters for and , indicating both hierarchical and feedback regulations. This study outlines the elaborate regulatory network of MBW complexes involving multiple MYBs which allow for the timely accumulation of anthocyanins in sweetpotato leaves. These results may also provide clues for similar studies of juvenile red fading in other plant species.
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http://dx.doi.org/10.3389/fpls.2020.00941DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7330089PMC
June 2020

Tsinghua facial expression database - A database of facial expressions in Chinese young and older women and men: Development and validation.

PLoS One 2020 15;15(4):e0231304. Epub 2020 Apr 15.

Department of Psychology, School of Social Sciences, Tsinghua University, Beijing, China.

Perception of facial identity and emotional expressions is fundamental to social interactions. Recently, interest in age associated changes in the processing of faces has grown rapidly. Due to the lack of older faces stimuli, most previous age-comparative studies only used young faces stimuli, which might cause own-age advantage. None of the existing Eastern face stimuli databases contain face images of different age groups (e.g. older adult faces). In this study, a database that comprises images of 110 Chinese young and older adults displaying eight facial emotional expressions (Neutral, Happiness, Anger, Disgust, Surprise, Fear, Content, and Sadness) was constructed. To validate this database, each image was rated on the basis of perceived facial expressions, perceived emotional intensity, and perceived age by two different age groups. Results have shown an overall 79.08% correct identification rate in the validation. Access to the freely available database can be requested by emailing the corresponding authors.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0231304PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7159817PMC
July 2020

Mechanochemical degradation of brominated flame retardants in waste printed circuit boards by Ball Milling.

J Hazard Mater 2020 03 25;385:121509. Epub 2019 Oct 25.

School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.

Degradation of brominated flame retardants (BFRs) in waste printed circuit boards (WPCBs) occurred due to mechanical force during the crushing process. In this study, a planetary ball-milling simulation experiment was designed to explore the mechanochemical debromination process of BFRs in WPCBs. The results showed that CaO had a better debromination performance than MgO and the mixture of Fe + SiO, and high revolution speed and low mass ratio of WPCBs to CaO promoted the degradation of BFRs. After milling for 1 h, the particle size distribution was stable while the debromination efficiency increased with the increase of milling time. Ball milling promoted the migration of bromine from the inside to the new surface of WPCBs powder, and submicron particles adhered to the micron size aggregates. The polybrominated diphenyl ethers (PBDEs) detection showed that the concentrations of most PBDE congeners decreased with the increase of milling time, and a possible degradation pathway was proposed according to the experimental results. All the results provided new data for the mechanism of degradation of BFRs in WPCBs during the mechanical crushing process.
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http://dx.doi.org/10.1016/j.jhazmat.2019.121509DOI Listing
March 2020

[Identification of dalbergia odorifera and dalbergia spp by solid phase microextraction-gas chromatography-mass spectrometry].

Se Pu 2018 May;36(5):493-498

Guangdong Institute of Analysis, Guangdong Provincial Key Laboratory of Emergency Test for Dangerous Chemicals, Guangzhou 510070, China.

In addition to species identification, the volatile components of dalbergia odorifera and dalbergia spp, were investigated by solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). Small amounts of powder samples were acquired by drilling from dalbergia, then the volatile components of the powder samples were concentrated by SPME, and separated by AB-FFAP polar capillary GC column. Of all the volatile components, twenty types were identified, and two pairs of them, 2-(1,1-dimethylethyl)-5-heptyl-5-methyl-1,3-dioxolan-4-one and 2,6,10-trimethyl-7,10-epoxy-2,11-dodecadien-6-ol, 2-methylbutylidene-cyclopentane and 2-(5-methyl-furan-2-yl)-propionaldehyde, could be considered specific volatile components for the identification of dalbergia odorifera and dalbergia spp, and the relative contents of these two pairs were compared for the species identification analysis. The method has the advantages of less sample requirement, simple operation, and no construction damage. The method is suitable for the research of volatile components and species identification analysis of dalbergia odorifera and dalbergia spp, and has broad prospective application in the analysis of furniture, art collections and raw wood of dalbergia.
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http://dx.doi.org/10.3724/SP.J.1123.2017.11058DOI Listing
May 2018

Pollution source localization in an urban water supply network based on dynamic water demand.

Environ Sci Pollut Res Int 2019 Jun 27;26(18):17901-17910. Epub 2017 Oct 27.

School of Computer Science, China University of Geosciences, Wuhan, Hubei, 430074, China.

Urban water supply networks are susceptible to intentional, accidental chemical, and biological pollution, which pose a threat to the health of consumers. In recent years, drinking-water pollution incidents have occurred frequently, seriously endangering social stability and security. The real-time monitoring for water quality can be effectively implemented by placing sensors in the water supply network. However, locating the source of pollution through the data detection obtained by water quality sensors is a challenging problem. The difficulty lies in the limited number of sensors, large number of water supply network nodes, and dynamic user demand for water, which leads the pollution source localization problem to an uncertainty, large-scale, and dynamic optimization problem. In this paper, we mainly study the dynamics of the pollution source localization problem. Previous studies of pollution source localization assume that hydraulic inputs (e.g., water demand of consumers) are known. However, because of the inherent variability of urban water demand, the problem is essentially a fluctuating dynamic problem of consumer's water demand. In this paper, the water demand is considered to be stochastic in nature and can be described using Gaussian model or autoregressive model. On this basis, an optimization algorithm is proposed based on these two dynamic water demand change models to locate the pollution source. The objective of the proposed algorithm is to find the locations and concentrations of pollution sources that meet the minimum between the analogue and detection values of the sensor. Simulation experiments were conducted using two different sizes of urban water supply network data, and the experimental results were compared with those of the standard genetic algorithm.
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http://dx.doi.org/10.1007/s11356-017-0516-yDOI Listing
June 2019

[Simultaneous rapid determination of 81 glucocorticoids in cosmetics by dispersive solid phase extraction and liquid chromatography-tandem mass spectrometry].

Se Pu 2017 Aug;35(8):816-825

Guangdong Provincial Key Laboratory of Emergency Test for Dangerous Chemicals, China National Analytical Center(Guangzhou), Guangzhou 510070, China.

A novel method was developed for the simultaneous rapid determination of 81 illegally added glucocorticoids (GCs) in cosmetics using dispersive-solid phase extraction (d-SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The analytes were extracted by acetonitrile after dispersing with water, and then purified using the C and primary secondary amine (PSA). The chromatographic separations were performed on a Poroshell 120 PFP column (100 mm×2.1 mm, 2.7 μ m) under multiple chromatographic retention modes. Acetonitrile and 0.2% (v/v) acetic acid aqueous solution were used as mobile phases with gradient elution, and all the 10 groups of isomers were baseline separated. The qualitative identification and quantitative analysis of the 81 GCs were operated in the electrospray ionization positive mode using dynamic multiple reaction monitoring (DMRM). The 81 GCs finally were quantified by internal standard method. The correlation coefficients of linear calibration curves were greater than 0.99 in the corresponding mass concentration ranges. The average recoveries of the 81 GCs at three spiked levels ranged from 68.8% to 105.3% with relative standard deviations (RSDs) of 2.9%-13.1% (=6). The LODs ( ≥ 3) and LOQs ( ≥ 10) were 0.002-0.006 μ g/g and 0.005-0.020 μ g/g, respectively. A number of 137 cosmetic samples submitted by customers were screened. Sixteen positive samples were found, and the contents of GCs were from 16.9 μ g/g to 158 μ g/g. The results showed that the new method is simple, rapid, sensitive and reliable, and it is suitable for qualitative and quantitative screening analysis of the 81 GCs in cosmetics simultaneously.
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http://dx.doi.org/10.3724/SP.J.1123.2017.04005DOI Listing
August 2017

Phylogeny and Expression Analyses Reveal Important Roles for Plant PKS III Family during the Conquest of Land by Plants and Angiosperm Diversification.

Front Plant Sci 2016 30;7:1312. Epub 2016 Aug 30.

Department of Chinese Cabbage, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences Beijing, China.

Polyketide synthases (PKSs) utilize the products of primary metabolism to synthesize a wide array of secondary metabolites in both prokaryotic and eukaryotic organisms. PKSs can be grouped into three distinct classes, types I, II, and III, based on enzyme structure, substrate specificity, and catalytic mechanisms. The type III PKS enzymes function as homodimers, and are the only class of PKS that do not require acyl carrier protein. Plant type III PKS enzymes, also known as chalcone synthase (CHS)-like enzymes, are of particular interest due to their functional diversity. In this study, we mined type III PKS gene sequences from the genomes of six aquatic algae and 25 land plants (1 bryophyte, 1 lycophyte, 2 basal angiosperms, 16 core eudicots, and 5 monocots). PKS III sequences were found relatively conserved in all embryophytes, but not exist in algae. We also examined gene expression patterns by analyzing available transcriptome data, and identified potential cis-regulatory elements in upstream sequences. Phylogenetic trees of dicots angiosperms showed that plant type III PKS proteins fall into three clades. Clade A contains CHS/STS-type enzymes coding genes with diverse transcriptional expression patterns and enzymatic functions, while clade B is further divided into subclades b1 and b2, which consist of anther-specific CHS-like enzymes. Differentiation regions, such as amino acids 196-207 between clades A and B, and predicted positive selected sites within α-helixes in late appeared branches of clade A, account for the major diversification in substrate choice and catalytic reaction. The integrity and location of conserved cis-elements containing MYB and bHLH binding sites can affect transcription levels. Potential binding sites for transcription factors such as WRKY, SPL, or AP2/EREBP may contribute to tissue- or taxon-specific differences in gene expression. Our data shows that gene duplications and functional diversification of plant type III PKS enzymes played a critical role in the ancient conquest of the land by early plants and angiosperm diversification.
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http://dx.doi.org/10.3389/fpls.2016.01312DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5004622PMC
September 2016

Mantle Subduction and Uplift of Intracontinental Mountains: A Case Study from the Chinese Tianshan Mountains within Eurasia.

Sci Rep 2016 06 29;6:28831. Epub 2016 Jun 29.

Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China.

The driving mechanism that is responsible for the uplift of intracontinental mountains has puzzled geologists for decades. This study addresses this issue by using receiver function images across the Chinese Tianshan Mountains and available data from both deep seismic profiles and surface structural deformation. The near-surface structural deformation shows that the Tianshan crust experienced strong shortening during the Cenozoic. The receiver function image across the Tianshan Mountains reveals that the lithosphere of the Junggar Basin to the north became uncoupled along the Moho, and the mantle below the Moho subducted southwards beneath the northern part of the Tianshan Mountains, thereby thickening the overlying crust. Similar deep structures, however, are not observed under the Tarim Basin and the adjacent southern Tianshan Mountains. This difference in the deep structures correlates with geomorphological features in the region. Thus, a new model of mantle subduction, herein termed M-type subduction, is proposed for the mountain-building processes in intracontinental compressional settings. The available geomorphological, geological and seismic data in the literatures show that this model is probably suitable for other high, linear mountains within the continent.
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http://dx.doi.org/10.1038/srep28831DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4926275PMC
June 2016

[Multiresidue analysis of 63 veterinary drugs in meat by dispersive solid-phase extraction and high performance liquid chromatography-tandem mass spectrometry].

Se Pu 2015 Apr;33(4):354-62

A novel multiresidue analytical method has been developed and validated for the determination of five classes of veterinary drugs including 18 β-lactams, 15 quinolones, 21 sulfonamides, 3 sulfonamide potentiators and 6 antiparasitics in meat using dispersive solid-phase extraction (dispersive-SPE) and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The analytes were extracted with a vortex mixer by 0.1 mol/L Na2 EDTA solution and acetonitrile containing 1% (v/v) acetic acid, and then the extracts were purified using dispersive-SPE with C18 sorbent. Electrospray ionization mass spectrometry was operated in positive mode using dynamic multiple reaction monitoring (DMRM) for the qualitative and quantitative analysis of the 63 analytes after the separation on a Poroshell EC-C18 column (100 mm x 2.1 mm, 2.4 µm). The correlation coefficients of linear calibration curves were over 0.99 in the corresponding concentration ranges. The average recoveries of the 63 analytes ranged from 62.2% to 112.0%, and the relative standard deviations (RSDs) were 3.1%-16.3% in spiked meat (pork, beef and chicken muscle) at three levels. The limits of detection (LODs, S/N ≥ 3) and the limits of quantification (LOQs, S/N ≥ 10) were 0.1-3.0 µg/kg and 0.5-10.0 µg/kg, respectively. The method is simple, rapid, sensitive, reliable and suitable for the determination of residues in animal products.
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http://dx.doi.org/10.3724/sp.j.1123.2014.12005DOI Listing
April 2015

Characterization of the cis elements in the proximal promoter regions of the anthocyanin pathway genes reveals a common regulatory logic that governs pathway regulation.

J Exp Bot 2015 Jul 23;66(13):3775-89. Epub 2015 Apr 23.

State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, 20 Nan Xin Cun, Beijing 100093, China University of Chinese Academy of Sciences, Beijing 100049, China

Cellular activities such as compound synthesis often require the transcriptional activation of an entire pathway; however, the molecular mechanisms underlying pathway activation have rarely been explained. Here, the cis regulatory architecture of the anthocyanin pathway genes targeted by the transcription factor (TF) complex including MYB, bHLH, and WDR was systematically analysed in one species and the findings extended to others. In Ipomoea purpurea, the IpMYB1-IpbHLH2-IpWDR1 (IpMBW) complex was found to be orthologous to the PAP1-GL3-TTG1 (AtPGT) complex of Arabidopsis thaliana, and interacted with a 7-bp MYB-recognizing element (MRE) and a 6-bp bHLH-recognizing element (BRE) at the proximal promoter region of the pathway genes. There was little transcription of the gene in the absence of the MRE or BRE. The cis elements identified experimentally converged on two syntaxes, ANCNNCC for MREs and CACN(A/C/T)(G/T) for BREs, and our bioinformatic analysis showed that these were present within anthocyanin gene promoters in at least 35 species, including both gymnosperms and angiosperms. For the anthocyanin pathway, IpMBW and AtPGT recognized the interspecific promoters of both early and later genes. In A. thaliana, the seed-specific TF complex (TT2, TT8, and TTG1) may regulate all the anthocyanin pathway genes, in addition to the proanthocyanidin-specific BAN. When multiple TF complexes in the anthocyanin pathway were compared, the cis architecture played a role larger than the TF complex in determining the variation in promoter activity. Collectively, a cis logic common to the pathway gene promoters was found, and this logic is essential for the trans factors to regulate the pathway.
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http://dx.doi.org/10.1093/jxb/erv173DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4473980PMC
July 2015

A valid strategy for precise identifications of transcription factor binding sites in combinatorial regulation using bioinformatic and experimental approaches.

Plant Methods 2013 Aug 24;9(1):34. Epub 2013 Aug 24.

State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, 20 Nan Xin Cun, Beijing 100093, China.

Background: Transcription factor (TF) binding sites (cis element) play a central role in gene regulation, and eukaryotic organisms frequently adapt a combinatorial regulation to render sophisticated local gene expression patterns. Knowing the precise cis element on a distal promoter is a prerequisite for studying a typical transcription process; however, identifications of cis elements have lagged behind those of their associated trans acting TFs due to technical difficulties. Consequently, gene regulations via combinatorial TFs, as widely observed across biological processes, have remained vague in many cases.

Results: We present here a valid strategy for identifying cis elements in combinatorial TF regulations. It consists of bioinformatic searches of available databases to generate candidate cis elements and tests of the candidates using improved experimental assays. Taking the MYB and the bHLH that collaboratively regulate the anthocyanin pathway genes as examples, we demonstrate how candidate cis motifs for the TFs are found on multi-specific promoters of chalcone synthase (CHS) genes, and how to experimentally test the candidate sites by designing DNA fragments hosting the candidate motifs based on a known promoter (us1 allele of Ipomoea purpurea CHS-D in our case) and applying site-mutagenesis at the motifs. It was shown that TF-DNA interactions could be unambiguously analyzed by assays of electrophoretic mobility shift (EMSA) and dual-luciferase transient expressions, and the resulting evidence precisely delineated a cis element. The cis element for R2R3 MYBs including Ipomoea MYB1 and Magnolia MYB1, for instance, was found to be ANCNACC, and that for bHLHs (exemplified by Ipomoea bHLH2 and petunia AN1) was CACNNG. A re-analysis was conducted on previously reported promoter segments recognized by maize C1 and apple MYB10, which indicated that cis elements similar to ANCNACC were indeed present on these segments, and tested positive for their bindings to Ipomoea MYB1.

Conclusion: Identification of cis elements in combinatorial regulation is now feasible with the strategy outlined. The working pipeline integrates the existing databases with experimental techniques, providing an open framework for precisely identifying cis elements. This strategy is widely applicable to various biological systems, and may enhance future analyses on gene regulation.
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http://dx.doi.org/10.1186/1746-4811-9-34DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3847620PMC
August 2013

Preparation and evaluation of zanamivir-loaded solid lipid nanoparticles.

J Control Release 2011 Nov;152 Suppl 1:e2-4

School of Pharmacy, Medical College of Soochow University, 199 Renai Road, Suzhou Industrial Park, Suzhou 215123, China.

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http://dx.doi.org/10.1016/j.jconrel.2011.08.085DOI Listing
November 2011

Preparation and evaluation of injectable sustained-release microspheres of rivastigmine.

J Control Release 2011 Nov;152 Suppl 1:e131-2

Department of Pharmaceutics, School of Pharmacy, Medical College of Soochow University, Suzhou 215123, China.

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http://dx.doi.org/10.1016/j.jconrel.2011.08.171DOI Listing
November 2011

[Determination of fatty alcohol polyoxyethylene ether sodium sulphate by liquid chromatography-electrospray ionization mass spectrometry].

Se Pu 2009 May;27(3):279-82

China National Analytical Center, Guangzhou 510070, China.

A method for the analysis of fatty alcohol polyoxyethylene ether sodium sulphate (AES) by liquid chromatography-electrospray ionization mass spectrometry (LC-ESI/MS) was established. The alkyl carbon number distribution, ethylene oxide number and average relative molecular mass in AES were determined by negative ion mode ESI/MS. Nitrogen nebulizer gas temperature was 325 degrees C, nitrogen drying gas flow rate was 5.00 L/min, the mass scan range was from m/z 100 to 1000. The free sodium dodecyl sulfate (SDS) in AES was separated on a Zorbax SB-C18 column (150 mm x 2.1 mm, 3.5 microm) with methanol-water (70:30, v/v) as the mobile phase at a flow rate of 0.3 mL/min, and then determined at m/z 265 by LC-MS with ESI in negative ion mode. The method has been applied for the determination of the AES samples, and the average ethylene oxide number was verified by nuclear magnetic resonance spectrum.
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May 2009