There is considerable interest to enhance the nutritional quality of fresh produce especially vegetables. The effects of root treatment of spinach with commercial extracts of the brown macro alga,
...Ascophyllum nodosum (ANE) on antioxidant level of spinach were studied. At the concentration of 1.0
g/L, ANE treatment significantly increased the total phenolics and flavonoids content, total antioxidant activity (as measured by DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging capacity) and Fe
2+ chelating ability in spinach leaves. The
1H NMR and LC-MS analyses of spinach extract suggests that the increased antioxidant activity is largely associated with flavonoids. The biological effect of ANE-enhanced polyphenols was tested using the
Caenorhabditis elegans nematode model. The extracts from ANE-treated spinach significantly improved the survival of the animals under oxidative stress by 50% and high temperature stress by 61% as compared to the extracts from untreated plants (0% and 38%, respectively). Taken together, the results suggest that ANE stimulate flavonoid synthesis in spinach leaf thus enhancing its nutritional quality. Furthermore, the increased flavonoid content exerts beneficial effects in
C. elegans against oxidative and heat stress.
Plant growth promoting rhizobacteria (PGPR) are a functionally diverse group of microbes having immense potential as biostimulants and stress alleviators. Their exploitation in agro-ecosystems as an ...eco-friendly and cost-effective alternative to traditional chemical inputs may positively affect agricultural productivity and environmental sustainability. The present study describes selected rhizobacteria, from a range of origins, having plant growth promoting potential under controlled conditions. A total of 98 isolates (ectophytic or endophytic) from various crop and uncultivated plants were screened, out of which four endophytes (n, L, K and Y) from Phalaris arundinacea, Solanum dulcamara, Scorzoneroides autumnalis, and Glycine max, respectively, were selected in vitro for their vegetative growth stimulating effects on Arabidopsis thaliana Col-0 seedlings with regard to leaf surface area and shoot fresh weight. A 16S rRNA gene sequencing analysis of the strains indicated that these isolates belong to the genera Pseudomonas, Bacillus, Mucilaginibacter and Rhizobium. Strains were then further tested for their effects on abiotic stress alleviation under both Petri-plate and pot conditions. Results from Petri-dish assay indicated strains L, K and Y alleviated salt stress in Arabidopsis seedlings, while strains K and Y conferred increases in fresh weight and leaf area under osmotic stress. Results from subsequent in vivo trials indicated all the isolates, especially strains L, K and Y, distinctly increased A. thaliana growth under both normal and high salinity conditions, as compared to control plants. The activity of antioxidant enzymes (ascorbate peroxidase, catalase and peroxidase), proline content and total antioxidative capacity also differed in the inoculated A. thaliana plants. Furthermore, a study on spatial distribution of the four strains, using either conventional Petri-plate counts or GFP-tagged bacteria, indicated that all four strains were able to colonize the endosphere of A. thaliana root tissue. Thus, the study revealed that the four selected rhizobacteria are good candidates to be explored as plant growth stimulators, which also possess salt stress mitigating property, partially by regulating osmolytes and antioxidant enzymes. Moreover, the study is the first report of Scorzoneroides autumnalis (fall dandelion) and Solanum dulcamara (bittersweet) associated endophytes with PGP effects.
With the development of advanced electronic devices and electric power systems, polymer-based dielectric film capacitors with high energy storage capability have become particularly important. ...Compared with polymer nanocomposites with widespread attention, all-organic polymers are fundamental and have been proven to be more effective choices in the process of scalable, continuous, and large-scale industrial production, leading to many dielectric and energy storage applications. In the past decade, efforts have intensified in this field with great progress in newly discovered dielectric polymers, fundamental production technologies, and extension toward emerging computational strategies. This review summarizes the recent progress in the field of energy storage based on conventional as well as heat-resistant all-organic polymer materials with the focus on strategies to enhance the dielectric properties and energy storage performances. The key parameters of all-organic polymers, such as dielectric constant, dielectric loss, breakdown strength, energy density, and charge–discharge efficiency, have been thoroughly studied. In addition, the applications of computer-aided calculation including density functional theory, machine learning, and materials genome in rational design and performance prediction of polymer dielectrics are reviewed in detail. Based on a comprehensive understanding of recent developments, guidelines and prospects for the future development of all-organic polymer materials with dielectric and energy storage applications are proposed.
Recently, RNA-guided genome editing using the type II clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein (Cas) system has been applied to edit the plant genome in ...several herbaceous plant species. However, it remains unknown whether this system can be used for genome editing in woody plants. In this study, we describe the genome editing and targeted gene mutation in a woody species, Populus tomentosa Carr. via the CRISPR/Cas9 system. Four guide RNAs (gRNAs) were designed to target with distinct poplar genomic sites of the phytoene desaturase gene 8 (PtoPDS) which are followed by the protospacer-adjacent motif (PAM). After Agrobacterium-mediated transformation, obvious albino phenotype was observed in transgenic poplar plants. By analyzing the RNA-guided genome-editing events, 30 out of 59 PCR clones were homozygous mutants, 2 out of 59 were heterozygous mutants and the mutation efficiency at these target sites was estimated to be 51.7%. Our data demonstrate that the Cas9/sgRNA system can be exploited to precisely edit genomic sequence and effectively create knockout mutations in woody plants.
Panax ginseng
is a traditional Chinese medicine with significant pharmaceutical effects and broad application. Rare ginsenosides with high antitumor activities can be generated via oriented ...modification of their glycosyl moiety. For this purpose, suitable microorganisms and their enzymatic systems can be used. In this review, we address several issues associated with these systems. Under aerobic conditions, fungus biotransformation provides an efficient and inexpensive biotransformation process that can be easily scaled up. Considering the profound use of probiotics, wild strains generally recognized as safe have shown a potential through classical fermentation in food manufacturers of deglycosylated ginsenosides. Commonly applied recombinant enzymes from
E. coli
, especially recombinant hyperthermophilic enzymes, showed efficient conversion in biomedical or pharmaceutical industries. In this review, key genes dedicated to the production of ginsenosides (especially in
Saccharomyces cerevisiae
) are highlighted in relation to the large-scale production of ginsenosides. We also evaluate biocatalytic strategies that are aimed to improve product specificity and biocatalytic efficiency with industrial applications. Perspectives of protein engineering and solvent engineering in the development and large-scale preparation of ginsenosides in anticancer drugs, food and health care products are explored.
Key Points
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Modification of ginsenosides with food/engineered microorganisms is summarized.
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Optimization of cell factories by protein engineering remains challenging.
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Solvent engineering offers an attractive potential alternative.
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•LiBr hydrate/acetone system is efficient for converting crystalline cellulose (MCC) to 5-hydroxymethylfurfural (5-HMF).•75.1% yield of 5-HMF together with 13.7% yield of glucose were ...obtained from MCC conversion with the addition of AlCl3.•DFT calculations indicated glucose isomerization rather than crystalline cellulose hydrolysis is the rate-determining step in cellulose conversion into 5-HMF.•Produced 5-HMF can be efficiently recovered by hyper-cross-linked polymer adsorption.•reaction system can be recycled 5 times without reducing 5-HMF selectivity.
5-hydroxymethylfurfural (5-HMF) is a crucial biomss-derived fuel precursor with versatile conversion pathways to advanced fuels. However, direct production of 5-HMF from crystalline cellulose is critical challenging due to the inefficient deconstruction of recalcitrant cellulose structure. Molten salt hydrates (MSHs) are unique in cellulose deconstruction and dissolution. In this work, a biphasic system of LiBr hydrate/acetone was established. It was found that 93.4% yield of 5-HMF can be efficiently converted from fructose without any catalysts. With the addition of AlCl3 to adjust Lewis acidity, an enhanced 5-HMF yield of 75.1% together with 13.7% of glucose were directly produced from cellulose, showing a promising carbon balance of 88.8%. A proposed mechanism for cellulose conversion was studied by density functional theory (DFT) calculations, demonstrating that the isomerization of glucose to fructose rather than crystalline cellulose hydrolysis was the rate-determining step. After reaction, the formed 5-HMF can be efficiently recycled from solvent via hyper-cross-linked polymer adsorption and the reaction system can be recycled for more than 5 times without reducing 5-HMF selectivity.
Quantitative understanding of the photophysical processes is essential for developing novel thermally activated delayed fluorescence (TADF) materials. Taking as an example ...1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene, a typical TADF-active molecule, we calculated the interconversion and decay rates of the lowest excited singlet and triplet states at different temperatures as well as the prompt and delayed fluorescence efficiencies at 300 K at the first-principles level. Our results can reproduce well the experimentally available data. It is found that the reverse intersystem crossing rate (k RISC) is sharply increased by 3 orders of magnitude, while the other rates increase slightly or remain unchanged when the temperature rises from 77 to 300 K. Importantly, k RISC reaches up to 1.23 × 106 s–1 and can compete with the radiative and nonradiative decay rates of S1 (1.11 × 107 and 2.37 × 105 s–1) at 300 K, leading to an occurrence of delayed fluorescence. In addition, our calculations indicate that it is the freely rotational motions of the carbazolyl between two cyano groups that are responsible for the interconversion between S1 and T1. The large torsional barriers of other three adjacent carbazolyl groups block the nonradiative decay channels of S1 → S0, leading to strong fluorescence. This work would provide useful insight into the molecular design of high-efficiency TADF emitters.
Summary
The secondary cell wall is an important carbon sink in higher plants and its biosynthesis requires coordination of metabolic fluxes in the phenylpropanoid pathway. In Arabidopsis (Arabidopsis ...thaliana), MYB75 and the KNOX transcription factor KNAT7 form functional complexes to regulate secondary cell wall formation in the inflorescence stem. However, the molecular mechanism by which these transcription factors control different branches of the phenylpropanoid pathway remains poorly understood in woody species. We isolated an R2R3‐MYB transcription factor MYB6 from Populus tomentosa and determined that it was expressed predominately in young leaves. Overexpression of MYB6 in transgenic poplar upregulated flavonoid biosynthetic gene expression, resulting in significantly increased accumulation of anthocyanin and proanthocyanidins. MYB6‐overexpression plants showed reduced secondary cell wall deposition, accompanied by repressed expression of secondary cell wall biosynthetic genes. We further showed that MYB6 interacted physically with KNAT7 and formed functional complexes that acted to repress secondary cell wall development in poplar and Arabidopsis. The results provide an insight into the transcriptional mechanisms involved in the regulation of the metabolic fluxes between the flavonoid and lignin biosynthetic pathways in poplar.
Significance Statement
The poplar MYB6 transcription factor is involved in the positive regulation of anthocyanin and proanthocyanidin biosynthesis but the inhibition of secondary cell wall formation with KNAT7 repressor.
High-performance work systems (HPWS)-performance research has dominated innovative human resource management studies for two decades. However, mainstream HPWS research has paid little attention to ...employees' perceptions of HPWS, or to the relationship between HPWS and corporate social performance (CSP). The influence of CSP on employee outcomes such as organizational commitment and organizational citizenship behaviour (OCB) has thus been similarly neglected. This paper seeks to investigate these missing links in literature using data collected from a sample of 700 employees in China. The findings demonstrate that HPWS is positively related to HPWS satisfaction and employees' perceptions of CSP. HPWS satisfaction fully mediates the relationship between HPWS and employees' affective commitment (AC). There are multiple mediators between HPWS and OCB, indicating more complicated mechanisms through which HPWS leads to desired HR outcomes. Employees' perceived CSP has a significant influence on HPWS satisfaction, AC and OCB, suggesting firms should place a premium on achieving a reputation as being socially responsible.
Through the lens of institutional work – the institutionally embedded practice that aims to create, maintain, or disrupt the rules and shared meanings in social life, we discuss how an emerging ...economy’s governments establish policies and regulations to develop outward foreign direct investment, and how domestic firms seek to shape these institutional arrangements to suit their interests and needs as they expand overseas. This study underscores the importance of the home country to multinational enterprises. We argue, the policymaking that underpins the internationalization of firms is not only a top-down (state inspired) but also a bottom-up process.
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