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Browsing by Author "Zhang, Qiang"

Now showing 1 - 5 of 5
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    Droplet-Based Microfluidics for High-Throughput Single-Cell Omics Profiling
    Zhang, Qiang (Virginia Tech, 2022-09-06)
    Droplet-based microfluidics is a powerful tool permitting massive-scale single-cell analysis in pico-/nano-liter water-in-oil droplets. It has been integrated into various library preparation techniques to accomplish high-throughput scRNA-seq, scDNA-seq, scATAC-seq, scChIP-seq, as well as scMulti-omics-seq. These advanced technologies have been providing unique and novel insights into both normal differentiation and disease development at single-cell level. In this thesis, we develop four new droplet-based tools for single-cell omics profiling. First, the developed Drop-BS is the first droplet-based platform to construct single-cell bisulfite sequencing libraries for DNA methylome profiling and allows production of BS library of 2,000-10,000 single cells within 2 d. We applied the technology to separately profile mixed cell lines, mouse brain tissues, and human brain tissues to reveal cell type heterogeneity. Second, the new Drop-ChIP platform only requires two steps of droplet generation to achieve multiple steps of reactions in droplets such as single-cell lysis, chromatin fragmentation, ChIP, and barcoding. Third, we aim to establish a droplet-based platform to accomplish high-throughput full-length RNA-seq (Drop-full-seq), which both current tube-based and droplet-based methods cannot realize. Last, we constructed an in-house droplet-based tool to assist single-cell ATAC-seq library preparation (Drop-ATAC), which provided a low-cost and facile protocol to conduct scATAC-seq in laboratories without the expensive instrument.
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    Humic Acid Promotes the Growth of Switchgrass under Salt Stress by Improving Photosynthetic Function
    Zhang, Jiaxing; Meng, Qiuxia; Yang, Zhiping; Zhang, Qiang; Yan, Min; Hou, Xiaochan; Zhang, Xunzhong (MDPI, 2024-05-19)
    As a potential crop in saline-alkali land, the growth of switchgrass could also be threatened by salt stress. Promoting the growth of switchgrass under salt stress by humic acid has great significance in the utilization of saline-alkali land. In this study, a pot experiment was arranged to investigate the responses of photosynthetic and physicochemical characteristics of switchgrass to HA under salt stress. Results showed that humic acid increased the photosynthetic function of switchgrass and enhanced plant height by 41.1% and dry weight by 26.9% under salt stress. Correlation analysis showed that the membrane aquaporin gene PvPIP1, malondialdehyde, ascorbate peroxidase, abscisic acid, polyamine, and jasmonic acid were important factors affecting the photosynthetic function of switchgrass in this study. Meanwhile, HA reduced the content of malondialdehyde, indicating the alleviation of the membrane damage caused by salt stress. On the other hand, HA upregulated the relative expression of the PvPIP1 gene and activated ascorbate peroxidase, abscisic acid, polyamine, and jasmonic acid in switchgrass to resist salt stress. These improved the membrane stability and promoted the photosynthetic activity of switchgrass to enhance the plant’s tolerance against salt stress and growth. Results from this study are helpful to the efficient growing of switchgrass and the sustainable development of saline-alkali land.
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    Physiological Mechanism of Enhancing Salt Stress Tolerance of Perennial Ryegrass by 24-Epibrassinolide
    Wu, Wenli; Zhang, Qiang; Ervin, Erik H.; Yang, Zhiping; Zhang, Xunzhong (Frontiers, 2017-06-19)
    Brassinosteroids (BR) regulate plant tolerance to salt stress but the mechanisms underlying are not fully understood. This study was to investigate physiological mechanisms of 24-epibrassinolide (EBR)'s impact on salt stress tolerance in perennial ryegrass (Lolium perenne L.) The grass seedlings were treated with EBR at 0, 10, and 100 nM, and subjected to salt stress (250 mM NaCl). The grass irrigated with regular water without EBR served as the control. Salt stress increased leaf electrolyte leakage (EL), malondialdehyde (MDA), and reduced photosynthetic rate (Pn). Exogenous EBR reduced EL and MDA, increased Pn, chlorophyll content, and stomatal conductance (gs). The EBR applications also alleviated decline of superoxide dismutase (SOD) and catalase (CAT) and ascorbate peroxidase (APX) activity when compared to salt treatment alone. Salt stress increased leaf abscisic acid (ABA) and gibberellin A4 (GA4) content but reduced indole-3-acetic acid (IAA), zeatin riboside (ZR), isopentenyl adenosine (iPA), and salicylic acid (SA). Exogenous EBR at 10 nm and 100 nM increased ABA, and iPA content under salt stress. The EBR treatment at 100 nM also increased leaf IAA, ZR, JA, and SA. In addition, EBR treatments increased leaf proline and ions (K+, Mg2+, and Ca2+) content, and reduced Na+/K+ in leaf tissues. The results of this study suggest that EBR treatment may improve salt stress tolerance by increasing the level of selected hormones and antioxidant enzyme (SOD and CAT) activity, promoting accumulation of proline and ions (K+, Ca2+, and Mg2+) in perennial ryegrass.
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    The Preparation of W/O/W High-Internal-Phase Emulsions as Coagulants for Tofu: The Effect of the Addition of Soy Protein Isolate in the Internal Water Phase
    Wang, Yongquan; Liu, Xuanbo; Zhang, Qiang (MDPI, 2024-08-29)
    Tofu quality is determined by a controlled coagulation process using a W/O/W emulsion coagulant. The impact of adding soy protein isolate (SPI) to the inner water phase on the stability of W/O/W high-internal-phase emulsions (HIPEs) and its application as a coagulant for tofu was assessed. No creaming occurred during 7-day storage with SPI concentrations up to 0.3%, while the emulsion droplets aggregated with 0.5% and 0.7% SPI. Emulsions containing 0.3% SPI maintained a constant mean droplet size after 21 days of storage and exhibited the lowest TURBISCAN stability index value. HIPE stability against freeze–thaw cycles improved after heating. HIPEs with SPI concentrations above 0.3% demonstrated an elastic gel-like behavior. The increased viscosity and aggregation of the protein around droplets indicated that the interaction among emulsion droplets could enhance stability. W/O/W HIPE coagulants significantly increased tofu yield, reduced hardness, and produced a more homogenous tofu gel compared to a MgCl2 solution. The HIPE with 0.3% SPI was found to be optimal for use as a coagulant for tofu.
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    Studies on the structure and the magnetic properties of high-entropy spinel oxide (MgMnFeCoNi)Al2O4
    Krysko, Evan; Min, Lujin; Wang, Yu; Zhang, Na; Barber, John P.; Niculescu, Gabriela E.; Wright, Joshua T.; Li, Fankang; Burrage, Kaleb; Matsuda, Masaaki; Robinson, Robert A.; Zhang, Qiang; Katzbaer, Rowan; Schaak, Raymond; Terrones, Mauricio; Rost, Christina M.; Mao, Zhiqiang (AIP Publishing, 2023-10-20)
    The study of high-entropy materials has attracted enormous interest since they could show new functional properties that are not observed in their related parent phases. Here, we report single crystal growth, structure, thermal transport, and magnetic property studies on a novel high-entropy oxide with the spinel structure (MgMnFeCoNi)Al2O4. We have successfully grown high-quality single crystals of this high-entropy oxide using the optical floating zone growth technique for the first time. The sample was confirmed to be a phase pure high-entropy oxide using x-ray diffraction and energy-dispersive spectroscopy. Through magnetization measurements, we found (MgMnFeCoNi)Al2O4 exhibits a cluster spin glass state, though the parent phases show either antiferromagnetic ordering or spin glass states. Furthermore, we also found that (MgMnFeCoNi)Al2O4 has much greater thermal expansion than its CoAl2O4 parent compound using high resolution neutron Larmor diffraction. We further investigated the structure of this high-entropy material via Raman spectroscopy and extended x-ray absorption fine structure spectroscopy (EXAFS) measurements. From Raman spectroscopy measurements, we observed (MgMnFeCoNi)Al2O4 to display a combination of the active Raman modes in its parent compounds with the modes shifted and significantly broadened. This result, together with the varying bond lengths probed by EXAFS, reveals severe local lattice distortions in this high-entropy phase. Additionally, we found a substantial decrease in thermal conductivity and suppression of the low temperature thermal conductivity peak in (MgMnFeCoNi)Al2O4, consistent with the increased lattice defects and strain. These findings advance the understanding of the dependence of thermal expansion and transport on the lattice distortions in high-entropy materials.