97 research outputs found
Quercus texana ‘Jin Fen Shi Jia’: A New Colored Landscape Tree
Quercus L. is an important tree of the family Fagaceae, and widely distributed in Asia, Africa, Europe, and the Americas (Jiang et al. 2019). There are ∼500 species, which can be generally divided into two subgenera and eight sections (Chassé 2018). The section Lobatae is naturally distributed in North America, Central America, and Colombia in South America. There are reports of breeding horticultural cultivars from tree species of this section in Europe and the United States. These cultivars include different leaf colors and tree shapes, such as Quercus coccinea ‘Splendens’, Quercus palustris Pacific Brilliance™ ‘PWJR08’ (bright red leaves in autumn), Quercus texana ‘New Madrid’ (red leaves in spring), Quercus rubra ‘Aurea’ (yellow leaves in spring), Q. texana Highpoint® ‘QNFTA’, Q. palustris Green Pillar® ‘Pringreen’ and Quercus phellos Hightower® ‘QPSTA’ (have narrow crown and are densely branched), and Q. palustris ‘Green Dwarf’ (low tree-shape) (Iqbal et al. 2017; Lancaster 1977; Russell et al. 2021; Torres-Miranda et al. 2011). Q. texana, also known as Nuttall’s oak, is a medium-sized deciduous tree with rapid growth, strong adaptability, and high ornamental value (Costello et al. 2011). It belongs to the section Lobatae, which are native to the Mississippi River Basin in the southeastern United States (Barrón et al. 2017; Manos et al. 1999; Sargent 1918). The trunk of Q. texana is upright with a tower-shaped crown. The leaves of Q. texana are simple, with lobed and toothed margins, broad and rounded lobes, and leaf length of 10 to 15 cm. The leaves are green and give dense shade in summer, and then turn bright red or reddish-brown in autumn; the leaves remain until late in the year on the twigs. Q. texana is commonly used for landscaping purposes and timber production, fuel wood, firewood, and charcoal. The species is known for its straight grain, resistance to fungal decay, and overall durability, making it a desirable species for industrial applications such as flooring, paneling, and furniture (Wang et al. 2022).
This species is often chosen for landscape applications because of its adaptable nature, rapid growth rate, and beautiful foliage. In recent years, researchers have been working to produce improved cultivars of Q. texana, and various new cultivars have been created with enhanced characteristics such as greater biotic and abiotic resistance, improved growth rate, and desirable foliage shapes and colors.
In China, some institutes have conducted systematic research since the 1990s on the introduction and cultivation of Q. texana. After screening, we selected some cultivars and provenances with good growth and strong adaptability (Chen et al. 2013). Now there are five cultivars of Q. texana authorized by the National Forestry and Grassland Administration (China): cultivars Yan Yu (red leaves in autumn), Long Xiang No. 7 and Long Xiang No. 10 (yellow leaves in spring), and Long Xiang No. 3 and Long Xiang No. 8 (red leaves in spring). The new cultivars possess excellent ornamental features and provide more options in landscape applications
Radioprotective Effect of Grape Seed Proanthocyanidins In Vitro and In Vivo
We have demonstrated that grape seed proanthocyanidins (GSPs) could effectively scavenge hydroxyl radical (•OH) in a dose-dependent manner. Since most of the ionizing radiation- (IR-) induced injuries were caused by •OH, this study was to investigate whether GSPs would mitigate IR-induced injuries in vitro and in vivo. We demonstrated that GSPs could significantly reduce IR-induced DNA strand breaks (DSBs) and apoptosis of human lymphocyte AHH-1 cells. This study also showed that GSPs could protect white blood cells (WBC) from IR-induced injuries, speed up the weight of mice back, and decrease plasma malondialdehyde (MDA), thus improving the survival rates of mice after ionizing radiation. It is suggested that GSPs have a potential as an effective and safe radioprotective agent
Genome sequencing and analysis of the paclitaxelproducing endophytic fungus \u3cem\u3ePenicillium aurantiogriseum\u3c/em\u3e NRRL 62431
Background
Paclitaxel (Taxol™) is an important anticancer drug with a unique mode of action. The biosynthesis of paclitaxel had been considered restricted to the Taxus species until it was discovered in Taxomyces andreanae, an endophytic fungus of T. brevifolia. Subsequently, paclitaxel was found in hazel (Corylus avellana L.) and in several other endophytic fungi. The distribution of paclitaxel in plants and endophytic fungi and the reported sequence homology of key genes in paclitaxel biosynthesis between plant and fungi species raises the question about whether the origin of this pathway in these two physically associated groups could have been facilitated by horizontal gene transfer.
Results
The ability of the endophytic fungus of hazel Penicillium aurantiogriseum NRRL 62431 to independently synthesize paclitaxel was established by liquid chromatography-mass spectrometry and proton nuclear magnetic resonance. The genome of Penicillium aurantiogriseum NRRL 62431 was sequenced and gene candidates that may be involved in paclitaxel biosynthesis were identified by comparison with the 13 known paclitaxel biosynthetic genes in Taxus. We found that paclitaxel biosynthetic gene candidates in P. aurantiogriseum NRRL 62431 have evolved independently and that horizontal gene transfer between this endophytic fungus and its plant host is unlikely.
Conclusions
Our findings shed new light on how paclitaxel-producing endophytic fungi synthesize paclitaxel, and will facilitate metabolic engineering for the industrial production of paclitaxel from fungi
The FilZ protein contains a single PilZ domain and facilitates the swarming motility of pseudoalteromonas sp. SM9913
Swarming regulation is complicated in flagellated bacteria, especially those possessing dual flagellar systems. It remains unclear whether and how the movement of the constitutive polar flagellum is regulated during swarming motility of these bacteria. Here, we report the downregulation of polar flagellar motility by the c-di-GMP effector FilZ in the marine sedimentary bacterium Pseudoalteromonas sp. SM9913. Strain SM9913 possesses two flagellar systems, and filZ is located in the lateral flagellar gene cluster. The function of FilZ is negatively controlled by intracellular c-di-GMP. Swarming in strain SM9913 consists of three periods. Deletion and overexpression of filZ revealed that, during the period when strain SM9913 expands quickly, FilZ facilitates swarming. In vitro pull-down and bacterial two-hybrid assays suggested that, in the absence of c-di-GMP, FilZ interacts with the CheW homolog A2230, which may be involved in the chemotactic signal transduction pathway to the polar flagellar motor protein FliMp, to interfere with polar flagellar motility. When bound to c-di-GMP, FilZ loses its ability to interact with A2230. Bioinformatic investigation indicated that filZ-like genes are present in many bacteria with dual flagellar systems. Our findings demonstrate a novel mode of regulation of bacterial swarming motility
Boosting oxygen evolution reaction by activation of lattice‐oxygen sites in layered Ruddlesden‐Popper oxide
Emerging anionic redox chemistry presents new opportunities for enhancing oxygen evolution reaction (OER) activity considering that lattice-oxygen oxidation mechanism (LOM) could bypass thermodynamic limitation of conventional metal-ion participation mechanism. Thus, finding an effective method to activate lattice-oxygen in metal oxides is highly attractive for designing efficient OER electrocatalysts. Here, we discover that the lattice-oxygen sites in Ruddlesden-Popper (RP) crystal structure can be activated, leading to a new class of extremely active OER catalyst. As a proof-of-concept, the RP Sr3(Co0.8Fe0.1Nb0.1)2O7-δ (RP-SCFN) oxide exhibits outstanding OER activity (eg, 334 mV at 10 mA cm−2 in 0.1 M KOH), which is significantly higher than that of the simple SrCo0.8Fe0.1Nb0.1O3-δ perovskite and benchmark RuO2. Combined density functional theory and X-ray absorption spectroscopy studies demonstrate that RP-SCFN follows the LOM under OER condition, and the activated lattice oxygen sites triggered by high covalency of metal-oxygen bonds are the origin of the high catalytic activity.This work was financially supported by the Australian Research Council (Discovery Early Career Researcher Award No. DE190100005)
Tuning Reconstruction Level of Precatalysts to Design Advanced Oxygen Evolution Electrocatalysts
Surface reconstruction engineering is an effective strategy to promote the catalytic activities of electrocatalysts, especially for water oxidation. Taking advantage of the physicochemical properties of precatalysts by manipulating their structural self-reconstruction levels provide a promising methodology for achieving suitable catalysts. In this review, we focus on recent advances in research related to the rational control of the process and level of surface transformation ultimately to design advanced oxygen evolution electrocatalysts. We start by discussing the original contributions to surface changes during electrochemical reactions and related factors that can influence the electrocatalytic properties of materials. We then present an overview of current developments and a summary of recently proposed strategies to boost electrochemical performance outcomes by the controlling structural self-reconstruction process. By conveying these insights, processes, general trends, and challenges, this review will further our understanding of surface reconstruction processes and facilitate the development of high-performance electrocatalysts beyond water oxidation
Copper foam-derived electrodes as efficient electrocatalysts for conventional and hybrid water electrolysis
Electrochemical water splitting has been demonstrated as a promising technology for the renewable generation of green hydrogen from water. Despite the extensive progress in materials science, one particular challenge for further development towards industrial application lies in the rational design and exploitation of efficient and cost-effective materials, especially oxygen evolution reaction (OER) electrocatalysts at the anode. In addition, attempts to replace the OER with other more oxidizable anode reactions are being evaluated as a groundbreaking strategy for generating hydrogen at lower potentials and reducing overall energy costs while producing valuable chemicals simultaneously. Compared with Fe/Co/Ni-based compounds, Cu-based materials have not received extensive research attention for electrode designs despite their high conductivity and abundant earth reserves. In this review, combining with the advantages of a three-dimensional network structure of metal foams, we summarize recent progress on Cu foam (CF)-derived materials as efficient electrocatalysts towards pure water electrolysis and hybrid water electrolysis. The advantages of CF and design strategies to enhance the electrocatalytic activity and operational durability are presented first. Catalyst design and fabrication strategies are then highlighted and the structure-activity relationship is also discussed. Finally, we propose challenges and perspectives on self-supported electrodes beyond CF-derived materials
Characterization of the complete chloroplast genome sequence of Koelreuteria bipinnata
Koelreuteria bipinnata is an important ornamental tree with attractive flowers and fruits. In this study, we used next-generation sequencing technology to obtain the complete chloroplast genome of K. bipinnata. The entire genome was determined to be 163,863 bp in size, harboring a typical quadripartite structure with a large single copy (LSC) region of 90,240 bp, a small single copy (SSC) region of 18,883 bp, and a pair of 27,370 bp inverted repeat (IR) regions. The genome was predicted to contain 132 genes, including 84 protein-coding genes, 40 tRNA genes, and 8 rRNA genes. The overall GC content of K. bipinnata chloroplast genome was 37.29%. Phylogenetic analysis based on complete chloroplast genome sequences indicated that K. bipinnata was closely related to K. paniculate. This study would be useful for future population genetics studies and phylogenetic analysis of K. bipinnata
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