Publications by authors named "Keqin Chen"

13 Publications

  • Page 1 of 1

Metabolomic profile combined with transcriptomic analysis reveals the value of UV-C in improving the utilization of waste grape berries.

Food Chem 2021 Jun 4;363:130288. Epub 2021 Jun 4.

College of Enology, Viti-Viniculture Engineering Technology Center of State Forestry and Grassland Administration, Shaanxi Engineering Research Center for Viti-Viniculture, Heyang Viti-Viniculture Station, Northwest A&F University, Yangling 712100, China. Electronic address:

Table grape is a popular fruit worldwide. The quality of the appearance of table grapes directly affects their commercial value. Table grape bunches are usually carefully managed during production. At different developmental stages, a large number of grape berries are pruned as waste for commercial appearance, which leads to wasted resources. Ultraviolet-C (UV-C) can regulate the accumulation of secondary metabolites in fruits. In this study, metabolomic profile was combined with transcriptomic analysis technology to explore the value of UV-C in improving the utilization of waste grapes. The berries of the 'Jumeigui' grape were subjected to UV-C radiation treatment in the green-berry stage, veraison stage, and maturation stage. The results showed that UV-C could brown grape berries and decrease their sugar content at different developmental stages. Compared with other samples, those treated with UV-C in the veraison stage had the most upregulated metabolites, while samples in the green-berry stage had the most down-regulated metabolites. UV-C promoted the accumulation of stilbenes and some flavonoids in the berries at each developmental stage (especially at the green-berry and veraison stages). Compared with other stages, UV-C treatment during the veraison stage led to the highest number of upregulated genes related to transcription factors, protein modification, indole-3-acetic acid (IAA), abscisic acid (ABA), gibberellin acid (GA), receptor kinases, and Ascorbic acid/Glutathione (Ascorb/Gluath). UV-C might promote the accumulation of phenolic components by upregulating the expression of their biosynthesis related genes. UV-C may be an effective in vitro approach for improving the application value of waste grape berries by enhancing the accumulation of the nutritious phenolic components.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.foodchem.2021.130288DOI Listing
June 2021

Dissociation of Biomolecules by an Intense Low-Energy Electron Beam in a High Sensitivity Time-of-Flight Mass Spectrometer.

J Am Soc Mass Spectrom 2021 Jun 3. Epub 2021 Jun 3.

Sciex, 71 Four Valley Drive Concord, Ontario L4K 4V8, Canada.

We report the progress on an electron-activated dissociation (EAD) device coupled to a quadrupole TOF mass spectrometer (QqTOF MS) developed in our group. This device features a new electron beam optics design allowing up to 100 times stronger electron currents in the reaction cell. The electron beam current reached the space-charge limit of 0.5 μA at near-zero electron kinetic energies. These advances enable fast and efficient dissociation of various analytes ranging from singly charged small molecules to multiply protonated proteins. Tunable electron energy provides access to different fragmentation regimes: ECD, hot ECD, and electron-impact excitation of ions from organics (EIEIO). The efficiency of the device was tested on a wide range of precursor charge states. The EAD device was installed in a QqTOF MS employing a novel trap-and-release strategy facilitating spatial mass focusing of ions at the center of the TOF accelerator. This technique increased the sensitivity 6-10 times and allows for the first time comprehensive structural lipidomics on an LC time scale. The system was evaluated for other compound classes such as intact proteins and glycopeptides. Application of hot ECD for the analysis of glycopeptides resulted in rich fragmentation with predominantly peptide backbone fragments; however, glycan fragments attributed to the ECD process were also observed. A standard small protein ubiquitin (8.6 kDa) was sequenced with 90% cleavage coverage at spectrum accumulation times of 100 ms and 98% at 800 ms. Comparable cleavage coverage for a medium-size protein (carbonic anhydrase: 29 kDa) could be achieved, albeit with longer accumulation times.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jasms.0c00425DOI Listing
June 2021

Transcriptomic and Metabolomic Basis of Short- and Long-Term Post-Harvest UV-C Application in Regulating Grape Berry Quality Development.

Foods 2021 Mar 16;10(3). Epub 2021 Mar 16.

College of Enology, Northwest A&F University, Yangling 712100, China.

In this study, ultraviolet-C (UV-C) was utilized to improve the quality of post-harvest grape berries, and the transcriptomic and metabolomic basis of this improvement was elucidated. Berries of the red grape variety 'Zicui' and the white variety 'Xiangfei' were chosen to evaluate the effect of short- and long-term UV-C irradiation. Post-harvest UV-C application promoted malondialdehyde (MDA) and proline accumulation, and reduced the soluble solid content in berries. Both the variety and duration of irradiation could modulate the transcriptomic and metabolomic responses of berries to UV-C. Compared with the control, the differentially expressed genes (DEGs) identified under UV-C treatment were enriched in pathways related to metabolite accumulation, hormone biosynthesis and signal transduction, and reactive oxygen species (ROS) homeostasis. Flavonoid biosynthesis and biosynthesis of other secondary metabolites were the shared pathways enriched with differential metabolites. After long-term UV-C irradiation, cis-resveratrol accumulated in the berries of the two varieties, while the differential chalcone, dihydroflavone, flavonoid, flavanol, and tannin components primarily accumulated in 'Xiangfei', and some flavonols and anthocyanins primarily accumulated in 'Zicui'. Based on an exhaustive survey, we made a summary for the effect of UV-C in regulating the quality development of post-harvest grape berries. The results of this study may help to elucidate the mechanism by which UV-C functions and support its efficient application.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/foods10030625DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8001394PMC
March 2021

Postharvest Dehydration Temperature Modulates the Transcriptomic Programme and Flavonoid Profile of Grape Berries.

Foods 2021 Mar 23;10(3). Epub 2021 Mar 23.

College of Enology, Viti-Viniculture Engineering Technology Center of State Forestry and Grassland Administration, Shaanxi Engineering Research Center for Viti-Viniculture, Heyang Viti-Viniculture Station, Northwest A&F University, Yangling 712100, China.

Raisins are a popular and nutritious snack that is produced through the dehydration of postharvest grape berries under high temperature (HT). However, the response of the endogenous metabolism of white grape varieties to postharvest dehydration under different temperature have not been fully elucidated to date. In this study, the white grape cultivar 'Xiangfei' was chosen to investigate the effect of dehydration at 50 °C, 40 °C, and 30 °C on the transcriptomic programme and metabolite profiles of grape berries. Postharvest dehydration promoted the accumulation of soluble sugar components and organic acids in berries. The content of gallic acid and its derivatives increased during the dehydration process and the temperature of 40 °C was the optimal for flavonoids and proanthocyanidins accumulation. High-temperature dehydration stress might promote the accumulation of gallic acid by increasing the expression levels of their biosynthesis related genes and regulating the production of NADP and NADPH. Compared with that at 30 °C, dehydration at 40 °C accelerated the transcription programme of 7654 genes and induced the continuous upregulation of genes related to the heat stress response and redox homeostasis in each stage. The results of this study indicate that an appropriate dehydration temperature should be selected and applied when producing polyphenols-rich raisins.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/foods10030687DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8005005PMC
March 2021

Effect of foliar application of fulvic acid antitranspirant on sugar accumulation, phenolic profiles and aroma qualities of Cabernet Sauvignon and Riesling grapes and wines.

Food Chem 2021 Jul 18;351:129308. Epub 2021 Feb 18.

College of Enology, Viti-Viniculture Engineering Technology Center of State Forestry and Grassland Administration, Shaanxi Engineering Research Center for Viti-Viniculture, Heyang Viti-Viniculture Station, Northwest A&F University, Yangling 712100, China. Electronic address:

This study investigated the effects of foliar application of fulvic acid antitranspirant (FA-AT) on Cabernet Sauvignon (CS) and Riesling grapes and wines in a warm viticulture region of China. FA-AT controlled the contents of total soluble solids, fructose and glucose in mature grapes and alcohol in wines. FA-AT improved total phenols and flavonoids in Riesling grapes, and total tannin and individual flavanols in CS grapes and wine, while reducing total individual phenolic acids and flavonols in CS wine. Increased volatiles in CS grapes (hexyl acetate, linalool) and wine (isoamyl alcohol, 1-hexanol, 2-phenylethanol) detected by SPME-GC-MS can contribute to the fruity and floral aroma. FA-AT reduced the accumulation of anthocyanins in CS grapes and wine without an eventual reduction in the tonality of wine by sensory analysis, and improved the taste and balance of Riesling wine. Overall, FA-AT can improve the quality of grapes and wines produced in warm viticulture regions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.foodchem.2021.129308DOI Listing
July 2021

Dual role of MdSND1 in the biosynthesis of lignin and in signal transduction in response to salt and osmotic stress in apple.

Hortic Res 2020 Dec 1;7(1):204. Epub 2020 Dec 1.

Group of Molecular Biology of Fruit Trees, College of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenyang, Liaoning, 110866, China.

Clarifying the stress signal transduction pathway would be helpful for understanding the abiotic stress resistance mechanism in apple (Malus × domestica Borkh.) and could assist in the development of new varieties with high stress tolerance by genetic engineering. The key NAC transcription factor SND1, which is involved in the lignin biosynthesis process in apple, was functionally analyzed. The results of the stress treatments indicated that MdSND1 could be induced by salt, mannitol and ABA. Compared with wild-type GL-3 plants, MdSND1-overexpressing apple plants with greater antioxidant capacity and lignin were more resistant to salt and simulated osmotic stress, while RNAi plants were more vulnerable. Additionally, molecular experiments confirmed that MdSND1 could regulate the biosynthesis of lignin by activating the transcription of MdMYB46/83. Moreover, genes known to be involved in the stress signal transduction pathway (MdAREB1A, MdAREB1B, MdDREB2A, MdRD29A, and MdRD22) were screened for their close correlations with the expression of MdSND1 and the response to salt and osmotic stress. Multiple verification tests further demonstrated that MdSND1 could directly bind to these gene promoters and activate their transcription. The above results revealed that MdSND1 is directly involved in the regulation of lignin biosynthesis and the signal transduction pathway involved in the response to both salt and osmotic stress in apple.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41438-020-00433-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7705020PMC
December 2020

Impacts Apple miR156 Precursor Levels via Ontogenetic Changes in Subcellular Glutathione Homeostasis.

Front Plant Sci 2019 31;10:994. Epub 2019 Jul 31.

College of Horticulture, China Agricultural University, Beijing, China.

The vegetative phase change in flowering plants is controlled by microRNA156 (miR156) under transcriptional regulation. However, the developmental signals upstream of miR156 are not well understood. The glutathione/glutathione disulfide (GSH/GSSG) ratios and GSH levels decline significantly during phase change, which is consistent with miR156 expression in apple ( Borkh.). Here, we found that the content of protein conjugated glutathione was remarkably higher in chloroplasts and nuclei of adult than juvenile phase apple hybrids. The decrease in miR156 expression was most relevant to the activities of serine acetyltransferase (SAT) and soluble γ-glutamyl transpeptidase (GGT), and the expressions of or . Transgenic apples over-expressing or miR156-mimetic (MIM156) did not alter expression or the soluble GGT activity. Inhibition of GGT activity with serine-borate complex or acivicin led to significant reduction in GSH content, the GSH/GSSG ratio, and the expressions of , , and miR156. Depletion of GSH with diethyl maleate without altering GGT activity caused a dramatic decrease in the expression of , , and miR156. Manipulating GGT activity and GSH homeostasis by transgenic over-expressing or RNAi increased or decreased and levels, respectively. These data provided novel evidence that participates in transcriptional level of transcription regulation of miR156 precursors during ontogenesis.

Highlights: - MdGGT1 affects thiol redox status and indirectly participates in the regulation of miR156 expression during vegetative phase change.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpls.2019.00994DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6684775PMC
July 2019

MdMYB46 could enhance salt and osmotic stress tolerance in apple by directly activating stress-responsive signals.

Plant Biotechnol J 2019 12 26;17(12):2341-2355. Epub 2019 May 26.

Group of Molecular Biology of Fruit Trees, College of Horticulture, Shenyang Agricultural University, Shenyang, Liaoning, China.

To expand the cultivation area of apple (Malus×domestica Borkh.) and select resistant varieties by genetic engineering, it is necessary to clarify the mechanism of salt and osmotic stress tolerance in apple. The MdMYB46 transcription factor was identified, and the stress treatment test of MdMYB46-overexpressing and MdMYB46-RNAi apple lines indicated that MdMYB46 could enhance the salt and osmotic stress tolerance in apple. In transgenic Arabidopsis and apple, MdMYB46 promoted the biosynthesis of secondary cell wall and deposition of lignin by directly binding to the promoter of lignin biosynthesis-related genes. To explore whether MdMYB46 could coordinate stress signal transduction pathways to cooperate with the formation of secondary walls to enhance the stress tolerance of plants, MdABRE1A, MdDREB2A and dehydration-responsive genes MdRD22 and MdRD29A were screened out for their positive correlation with osmotic stress, salt stress and the transcriptional level of MdMYB46. The further verification test demonstrated that MdMYB46 could activate their transcription by directly binding to the promoters of these genes. The above results indicate that MdMYB46 could enhance the salt and osmotic stress tolerance in apple not only by activating secondary cell wall biosynthesis pathways, but also by directly activating stress-responsive signals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/pbi.13151DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6835124PMC
December 2019

The FvPHR1 transcription factor control phosphate homeostasis by transcriptionally regulating miR399a in woodland strawberry.

Plant Sci 2019 Mar 28;280:258-268. Epub 2018 Dec 28.

Liaoning Key Laboratory of Strawberry Breeding and Cultivation, College of Horticulture, Shenyang Agricultural University, Shenyang 110866, China. Electronic address:

Plants have evolved phosphate (Pi) starvation response to adapt the low-Pi environment. The regulation of adaptive responses to phosphorus deficiency by the PHR1-miR399-PHO2 module has been well studied in Arabidopsis thaliana but not in strawberry. Transcription factor PHR1 as the central regulator in the Pi starvation signaling has been revealed in a few plant species. However, the function of PHR1 homologues in strawberry is still unknown. In this study, a total of 13 MYB-CC genes were identified in the woodland strawberry (Fragaria vesca) genome and the FvPHR1 gene was characterized. FvPHR1 contains MYB domain and coiled-coil (CC) domain and is localized in the nucleus. FvPHR1 also exhibits trans-activation ability. Furthermore, the P content in leaves of FvPHR1-overexpressing woodland strawberries was significantly increased by 1.38-fold to 1.78-fold compared with that in the wild type. FvPHR1 was also demonstrated to directly bind to the FvMIR399a promoter and positively regulate the expression of FvmiR399a in woodland strawberry. These results showed that PHR1-miR399 module is involved in the regulation of phosphate-signaling pathway and phosphate homeostasis in woodland strawberry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.plantsci.2018.12.025DOI Listing
March 2019

FveRGA1, encoding a DELLA protein, negatively regulates runner production in Fragaria vesca.

Planta 2018 Apr 29;247(4):941-951. Epub 2017 Dec 29.

College of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenyang, 110866, China.

Main Conclusion: FveRGA1 was highly expressed in tender tissues such as young leaves and stem apices and was localized in the nucleus. RNAi silencing of FveRGA1 in non-runnering woodland strawberry produced many runners. FveRGA1 is thus a key gene controlling strawberry runner formation. The propagation of strawberry is mainly based on runners, while the genes controlling runner production have not been well characterized. Exogenous applications of optimum concentration gibberellins (GAs) promote runner formation in strawberry cultivation and GA can accelerate the degradation of DELLA proteins. To investigate whether DELLA proteins are responsible for runner production, we analyzed all the DELLA genes in Fragaria vesca and cloned a DELLA protein-encoding gene FveRGA1 in woodland strawberry using RT-PCR. Subcellular localization analysis indicated that FveRGA1 was localized in the nucleus. A transcription analysis suggested that FveRGA1 was expressed ubiquitously in all examined strawberry organs, especially in young leaves, petioles, and stem apices. RNA interference (RNAi) technology was carried out to investigate the function of FveRGA1 in woodland strawberry 'Yellow Wonder' (YW) and 'Ruegen' (RG) via an Agrobacterium-mediated transformation. Interestingly, the RNAi silencing transgenic plants in the naturally non-runnering YW and RG strains produced many runners, suggesting FveRGA1 as a key gene controlling strawberry runner formation. Our study lays a solid basis for unraveling the detailed molecular mechanism of runner formation in strawberry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00425-017-2839-9DOI Listing
April 2018

Microwave Hydrothermal Synthesis of Terbium Ions Complexed with Porous Graphene for Effective Absorbent for Organic Dye.

Nanoscale Res Lett 2017 Dec 20;12(1):204. Epub 2017 Mar 20.

Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204, People's Republic of China.

A luminescent terbium ions/reduced graphene oxide complex (Tb-RGO) was successfully and rapidly synthesized by the microwave hydrothermal reaction via the interactions between terbium ions and the active oxygen functional groups of graphene oxide. The as-prepared material was porous stacked by multilayer graphene in all directions. Thus, the resulting product owed the high specific surface area, high adsorption capacity and ultra-fast adsorption rate. Combined with the characteristic photoluminescence derived from terbium ions, the material has potential applications in biosensing and environmental protection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s11671-017-1962-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5359191PMC
December 2017

Vertical optical sectioning using a magnetically driven confocal microscanner aimed for in vivo clinical imaging.

Opt Express 2011 Dec;19(25):25161-72

Department of Mechanical Engineering, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.

This paper presents a confocal microscanner for direct vertical optical sectioning of biological samples. Confocal imaging is performed by transverse (X-axis) and axial (Z-axis) scanning of a focused laser beam using an optical fiber and a microlens respectively. The actuators are fabricated by laser micromachining techniques and are driven by electromagnetic forces. Optical and mechanical performance of the system is predicted by simulation software packages and characterized by experimental measurements. The scanner has lateral resolution of 3.87 µm and axial resolution of 10.68 µm with a field of view of 145 µm in X and 190 µm in Z directions. Confocal imaging of a polymer layer deposited on a silicon wafer and onion epidermal cells is demonstrated.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/OE.19.025161DOI Listing
December 2011

Radio aneurysm coils for noninvasive detection of cerebral embolization failures: a preliminary study.

Biosens Bioelectron 2011 Dec 1;30(1):300-5. Epub 2011 Oct 1.

Department of Electrical & Computer Engineering, University of British Columbia, Vancouver, BC, V6T 1Z4 Canada.

The rupture of a cerebral aneurysm is the most common cause of subarachnoid hemorrhage. Endovascular embolization of the aneurysms by implantation of Guglielmi detachable coils (GDC) has become a major treatment approach in the prevention of a rupture. Implantation of the coils induces formation of tissues over the coils, embolizing the aneurysm. However, blood entry into the coiled aneurysm often occurs due to failures in the embolization process. Current diagnostic methods used for aneurysms, such as X-ray angiography and computer tomography, are ineffective for continuous monitoring of the disease and require extremely expensive equipment. Here we present a novel technique for wireless monitoring of cerebral aneurysms using implanted embolization coils as radiofrequency resonant sensors that detect the blood entry. The experiments show that commonly used embolization coils could be utilized as electrical inductors or antennas. As the blood flows into a coil-implanted aneurysm, parasitic capacitance of the coil is modified because of the difference in permittivity between the blood and the tissues grown around the coil, resulting in a change in the coil's resonant frequency. The resonances of platinum GDC-like coils embedded in aneurysm models are detected to show average responses of 224-819 MHz/ml to saline injected into the models. This preliminary demonstration indicates a new possibility in the use of implanted GDC as a wireless sensor for embolization failures, the first step toward realizing long-term, noninvasive, and cost-effective remote monitoring of cerebral aneurysms treated with coil embolization.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bios.2011.09.033DOI Listing
December 2011
-->