Identification and Heterologous Reconstitution of a 5-Alk(en)ylresorcinol Synthase from Endophytic Fungus \u3ci\u3eShiraia\u3c/i\u3e sp. Slf14

A new type III polyketide synthase gene (Ssars) was discovered from the genome of Shiraia sp. Slf14, an endophytic fungal strain from Huperzia serrata. The intron-free gene was cloned from the cDNA and ligated to two expression vectors pET28a and YEpADH2p-URA3 for expression in Escherichia coli BL21(DE3) and Saccharomyces cerevisiae BJ5464, respectively. SsARS was efficiently expressed in E. coli BL21(DE3), leading to the synthesis of a series of polyketide products. Six major products were isolated from the engineered E. coli and characterized as 1,3-dihydroxyphenyl-5-undecane, 1,3-dihydroxyphenyl-5-cis-6\u27-tridecene,1,3-dihydroxyphenyl-5-tridecane, 1,3-dihydroxyphenyl-5-cis-8\u27-pentadecene, 1,3-dihydroxyphenyl-5-pentadecane and 1,3-dihydroxyphenyl-5-cis-10\u27-heptadecene, respectively, based on the spectral data and biosynthetic origin. Expression of SsARS in the yeast also led to the synthesis of the same polyketide products, indicating that this enzyme can be reconstituted in both heterologous hosts. Supplementation of soybean oil into the culture of E. coli BL21(DE3)/SsARS increased the production titers of 1-6 and led to the synthesis of an additional product, which was identified as 5-(8\u27Z,11\u27Z-heptadecadienyl)resorcinol. This work thus allowed the identification of SsARS as a 5-alk(en)ylresorcinol synthase with flexible substrate specificity toward endogenous and exogenous fatty acids. Desired resorcinol derivatives may be synthesized by supplying corresponding fatty acids into the culture medium

Relationship Between Matrix Cracking and Delamination in CFRP Cross-Ply Laminates Subjected to Low Velocity Impact

The effect of matrix cracking on the delamination morphology inside carbon fiber reinforced plastics (CFRP) laminates during low-velocity impact (LVI) is an open question. In this paper, the relationship between matrix cracking and delamination is studied by using cross-ply laminates. Several methods, including micrograph, C-scan, and visual inspection, were adopted to characterize the damage after LVI experiments. Based on the experimental results, finite element (FE) models were established to analyze the damage mechanisms. The matrix cracking was predicted by the extended finite element method (XFEM) and the Puck criteria, while the delamination was modeled by cohesive elements. It was revealed that the matrix crack in the bottom ply not only promoted the outward propagation of delamination but also contributed to the narrow delamination beneath the impact location. Multiple matrix cracks occurred in the middle ply. The ones close to the plate center initiated the delamination and prevented large-scale delamination beneath the impact location. For the cracks that were far away, no significant effect on delamination was found. In conclusion, the stress redistribution caused by the crack opening determines the delamination

Ultra-High-Density Ferroelectric Array Formed by Sliding Ferroelectric Moiré Superlattices

2D van der Waals (vdW) materials offer infinite possibilities for constructing unique ferroelectrics through simple layer stacking and rotation. In this work, we stack nonferroelectric GeS2 and ferroelectric CuInP2S6 to form heterostructures by combining sliding ferroelectric polarization with displacement ferroelectric polarization to achieve multiple polarization states. First-principles calculations reveal that the polarization reversal of the CuInP2S6 component in the GeS2/CuInP2S6/GeS2 heterostructure can simultaneously drive the switching of sliding ferroelectric polarization, displaying a robust coupling of the two polarizations and leading to the overall polarization switching. Based on this, ferroelectric arrays with a density of 6.55 × 1012 cm-2 (equivalent to a storage density of 0.7 TB cm-2) were constructed in a moiré superlattice, and the polarization strength of array elements was 11.77 pC/m, higher than that of all reported 2D vdW out-of-plane ferroelectrics. High density, large polarization, and electrically switchable array elements in ferroelectric arrays provide unprecedented opportunities to design 2D high-density nonvolatile ferroelectric memories

Theoretical Investigation of Topological Magnetic Textures in Sliding Ferroelectric CrX3 (X = Cl, Br, I) Moiré Superlattices: A Multiferroic Material with Unique Magnetoelectric Coupling for Information Storage Applications

Two-dimensional (2D) van der Waals (vdW) materials offer unprecedented possibilities for manipulating electrical and magnetic properties through layer twisting or sliding. In this study, we investigate the stack engineering of two magnetic monolayers, CrX3 (X = Cl, Br, I), by combining first-principles calculations and atomic spin dynamics simulations. The interlayer sliding of CrX3 bilayers disrupts space inversion symmetry, resulting in the emergence of ferroelectric polarization characterized by a low energy potential barrier and polarization reversal. Notably, as the halogen atoms change from Cl to I, the interlayer exchange interaction gradually intensifies, leading to a significant enhancement in both magnetic stability and ferroelectric polarization. Moreover, when a moiré superlattice is formed through small-angle twisting, the electrostatic moiré potential and magnetic exchange interaction coupling through layer stacking lead to the formation of staggered polarization domains and four distinct types of topological magnetic states, which starkly contrast with the nontwisted bilayer configuration. This work provides a pioneering example of designing sliding ferroelectricity in 2D vdW magnetic bilayers, showcasing the potential of nanoscale layered multiferroic materials constructed by twisted stacking engineering for application in novel information memory devices

Interleukin-37 is involved in the immunopathogenesis of infectious mononucleosis

Abstract Background Multiple immunopathological responses to viruses are observed in infectious mononucleosis (IM), a manifestation of primary infection with Epstein-Barr virus (EBV). Protective effects of the negative immunoregulatory molecule interleukin-37 (IL-37) have been observed in various bacterial and viral infections. However, the function of IL-37 in IM remains unknown. Methods Flow cytometry and enzyme-linked immunosorbent assay (ELISA) were used to determine the expression of IL-37 in the peripheral blood of patients diagnosed with IM, and the variation of lymphocyte subsets. Furthermore, the associations between IL-37 expression and the percentage of lymphocyte subgroups were analyzed. Results Patients with IM had severe immune dysfunction. The control group had a lower expression of IL-37 than the patients with IM. There were significant associations between IL-37 expression and both the proportion of CD3+T cells and the ratio of CD3+CD4+ to CD3+CD8+T cells. Patients with higher levels of IL-37 expression had lower levels of the liver inflammation indicators, alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Conclusions IL-37 may affect the immune pathogenesis of patients with IM infected with EBV, and may have immunotherapeutic benefit for EBV-associated illnesses

Microporous and stable covalent organic framework for effective gas uptake

Covalent organic frameworks (COFs) are a new class of crystalline porous materials, maintaining porosity, stability, uniform pore channel, and well-designed skeletons. These features trait to be well suited as a platform for effective adsorption and separation of sorbents. Here, we reported microporous and stable COF with high-density N and O atoms that are implanted via the linker and vertex design. The new COF possessed high crystallinity, permanent micropores, excellent thermal and chemical stability, and high-density N and O atoms on the walls. Interestingly, the new COF is able to capture CO2 of 14.2 wt%, and iodine vapor of 456 wt%. These results evolve structural designs of COFs as effective gas uptake scaffolds

Structural features of three hetero-galacturonans from Passiflora foetida fruits and their in vitro immunomodulatory effects

This article belongs to the Collection Polysaccharides.Passiflora foetida is a horticultural plant and vital traditional Chinese herbal medicine. In our previous study, the characterization and immuno-enhancing effect of fruits polysaccharide 1 (PFP1), a water-eluted hetero-mannan from wild Passiflora foetida fruits, were investigated. Herein, another three salt-eluted novel polysaccharides, namely PFP2, PFP3, and PFP4, were obtained and structurally characterized. The results showed that PFP2, PFP3, and PFP4 were three structurally similar hetero-galacturonans with different molecular weights of 6.11 × 104, 4.37 × 104, and 3.48 × 105 g/mol, respectively. All three of these hetero-galacturonans are mainly composed of galacturonic acid, galactose, arabinose (75.69%, 80.39%, and 74.30%, respectively), and other monosaccharides including mannose, fucose, glucose, ribose, xylose, and glucuronic acid (24.31%, 19.61, and 25.70%, respectively), although differences in their backbone structure exist. Additionally, immunomodulatory assay indicated that the three hetero-galacturonans possess the ability to promote the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in RAW264.7 macrophages in a concentration-dependent manner (p < 0.05). Especially, PFP3 displayed a stronger enhancing effect than PFP2 and PFP4 at the minimum effective concentration. Therefore, the results suggested that the obtained three salt-eluted hetero-galacturonans, especially PFP3, could be utilized as immunomodulatory effectivity ingredients in nutritional/pharmaceutical industries.This work was funded by Key Area R&D Program of Guangdong Province (NO. 2019B020211002), Science and Technology Planning Project of Guangzhou City (NO. 201804020077), Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (2017), International Cooperation Program of SCAU (NO. 2019SCAUGH03), and South China Agricultural University Doctoral Students (overseas) Joint Education Programs (NO. 2018LHPY003).Peer reviewe

Light-Emitting Conjugated Organic Polymer as an Efficient Fluorescent Probe for Cu2+ Ions Detection and Cell Imaging

Conjugated organic polymers (COPs) have been excellent candidates because the conjugated structure occupied pi structure that is useful to develop light-emitting materials. However, most COPs emitt weak luminescence owing to the H-aggregation effect. Light-emitting conjugated organic polymers (LCOP-1) possess rich butyl groups anchored in the skeleton to enhance light-emitting activity via reducing the H-aggregation effect. Owing to abundant hydroxyl and nitrogen atoms, LCOP-1 exhibits high sensitivity, selectivity, and fast response to Cu2+ ions within 1 min in comparison with the cations of Na+, Mg2+, Al3+, Zn2+, Cd2+, Ni2+, Cr3+, Hg2+, Fe3+, Fe2+, Pb2+, Co2+, etc. The detection limit can be down to nanomolar. Moreover, the sensor exhibits detection toward Cu2+ ions via a naked eye colorful change from pale-yellow to yellowish-brown. Furthermore, the light-emitting probe also successfully achieves the detection of Cu2+ ions in cells without cytotoxicity, indicating its great potentials in biological function