Homo- and Hetero-Dimers of CAD Enzymes Regulate Lignification and Abiotic Stress Response in Moso Bamboo

Lignin biosynthesis enzymes form complexes for metabolic channelling during lignification and these enzymes also play an essential role in biotic and abiotic stress response. Cinnamyl alcohol dehydrogenase (CAD) is a vital enzyme that catalyses the reduction of aldehydes to alcohols, which is the final step in the lignin biosynthesis pathway. In the present study, we identified 49 CAD enzymes in five Bambusoideae species and analysed their phylogenetic relationships and conserved domains. Expression analysis of Moso bamboo PheCAD genes in several developmental tissues and stages revealed that among the PheCAD genes, PheCAD2 has the highest expression level and is expressed in many tissues and PheCAD1, PheCAD6, PheCAD8 and PheCAD12 were also expressed in most of the tissues studied. Co-expression analysis identified that the PheCAD2 positively correlates with most lignin biosynthesis enzymes, indicating that PheCAD2 might be the key enzyme involved in lignin biosynthesis. Further, more than 35% of the co-expressed genes with PheCADs were involved in biotic or abiotic stress responses. Abiotic stress transcriptomic data (SA, ABA, drought, and salt) analysis identified that PheCAD2, PheCAD3 and PheCAD5 genes were highly upregulated, confirming their involvement in abiotic stress response. Through yeast two-hybrid analysis, we found that PheCAD1, PheCAD2 and PheCAD8 form homo-dimers. Interestingly, BiFC and pull-down experiments identified that these enzymes form both homo- and hetero- dimers. These data suggest that PheCAD genes are involved in abiotic stress response and PheCAD2 might be a key lignin biosynthesis pathway enzyme. Moreover, this is the first report to show that three PheCAD enzymes form complexes and that the formation of PheCAD homo- and hetero- dimers might be tissue specific.

A Comprehensive Study on the Dynamic Change of Thermal Behavior During Lignocellulose Pyrolysis Catalyzed by Plant-Rich Metallic Elements

Evaluating the pyrolysis of lignocellulose via theoretical and computational approaches is of great importance for the efficient utilization of biomass. In this work, the dynamic changes in physicochemical properties of eucalyptus and bamboo during plant-rich metallic element-catalyzed pyrolysis process were investigated, and their thermal decomposition behaviors were explored by kinetic analysis. Results showed that the metal absorption capacity and thermal stability of eucalyptus were better than those of bamboo. The temperatures corresponding to the initial devolatilization and the highest weight loss value of eucalyptus/bamboo decreased in the catalysis order of Mg > Fe > Ca > Cu > K > Na. Fourier-transform infrared (FT-IR) results showed that the thermal stability of ester bond of glucuronoarabinoxylan was higher than that of acetyl groups. The maximum weight loss rate could be observed for samples with the lowest metal-loaded concentration (5%). Moreover, Mg and Fe presented the better catalytic performance for facilitating the lignocellulose pyrolysis in comparison with other investigated metallic elements.

Fibroblast growth factor 21 attenuates iron overload-induced liver injury and fibrosis by inhibiting ferroptosis

Ferroptosis plays a role in several diseases such as iron overload-induced liver diseases. Manipulation of ferroptosis has been explored as a potential therapeutic strategy to treat related diseases. Numerous antioxidants have been identified to control ferroptosis but the cell-autonomous mechanisms responsible for regulating ferroptosis remain elusive. In the present study, we found that iron overload promoted ferroptosis in hepatocytes by excessively inducing HO-1 expression, which contributed to the progression of liver injury and fibrosis, accompanied by the upregulation of the FGF21 protein level in vitro and in vivo. Interestingly, both recombinant FGF21 and Fgf21 overexpression significantly protected against iron overload-induced hepatocytes mitochondria damage, liver injury and fibrosis by inhibiting ferroptosis. In contrast, the loss of FGF21 aggravated iron overload-induced ferroptosis. Notably, FGF21-induced HO-1 inhibition (via the promotion of HO-1 ubiquitination and degradation) and NRF2 activation provide a mechanistic explanation for this phenomenon. Taken together, we identified FGF21 as a novel ferroptosis suppressor. Thus, FGF21 activation may provide an effective strategy for the potential treatment of iron overload-induced ferroptosis-related diseases, such as hereditary haemochromatosis (HH).

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Iron overload robustly induces hepatic FGF21 expression both in vitro and in vivo.

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FGF21 suppresses iron overload-induced hepatocytes ferroptosis.

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Constitutive HO-1 activation contributes to iron overload-induced ferroptosis in hepatocytes.

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FGF21 protects hepatocytes from iron overload-induced ferroptosis by stimulating HO-1 ubiquitination and degradation.

GhLUX1 and GhELF3 Are Two Components of the Circadian Clock That Regulate Flowering Time of Gossypium hirsutum

Photoperiod is an important external factor that regulates flowering time, the core mechanism of which lies in the circadian clock-controlled expression of FLOWERING LOCUS T (FT) and its upstream regulators. However, the roles of the circadian clock in regulating cotton flowering time are largely unknown. In this study, we cloned two circadian clock genes in cotton, GhLUX1 and GhELF3. The physicochemical and structural properties of their putative proteins could satisfy the prerequisites for the interaction between them, which was proved by yeast two-hybrid (Y2H) and Bimolecular Fluorescent Complimentary (BiFC) assays. Phylogenetic analysis of LUXs and ELF3s indicated that the origin of LUXs was earlier than that of ELF3s, but ELF3s were more divergent and might perform more diverse functions. GhLUX1, GhELF3, GhCOL1, and GhFT exhibited rhythmic expression and were differentially expressed in the early flowering and late-flowering cotton varieties under different photoperiod conditions. Both overexpression of GhLUX1 and overexpression of GhELF3 in Arabidopsis delayed flowering probably by changing the oscillation phases and amplitudes of the key genes in the photoperiodic flowering pathway. Both silencing of GhLUX1 and silencing of GhELF3 in cotton increased the expression of GhCOL1 and GhFT and resulted in early flowering. In summary, the circadian clock genes were involved in regulating cotton flowering time and could be the candidate targets for breeding early maturing cotton varieties.

Chitosan oligosaccharide attenuates endoplasmic reticulum stress-associated intestinal apoptosis via the Akt/mTOR pathway

Endoplasmic reticulum stress (ERS) and apoptosis are widely considered as essential factors associated with intestinal disorders, whereas nutritional therapeutic approaches targeting ERS may control disease activity. Thus, we focus on the potential benefit of chitosan oligosaccharide (COS) on repressing ERS and ERS-induced apoptosis. In this study, we used the ERS model with tunicamycin (TM)-induced IPEC-J2 cells in vitro and nutrient deprivation-induced ERS in piglets to evaluate the protective mechanism of COS against ERS and ERS-induced apoptosis. The results showed that cells were characterized by activation of the unfolded protein response (UPR) and increased epithelial apoptosis upon exposure to TM. However, these changes were significantly attenuated by COS and the expressions of Akt and mTORC1 were inhibited. Furthermore, a specific inhibitor of mTOR confirmed the suppression of Akt and reduced the activation of the UPR and apoptosis. In vivo, COS protected against nutrient deprivation-induced ERS in the jejunum of piglets, in which the overexpression of the UPR and apoptosis was rescued. Consistently, COS attenuated nutrient deprivation-induced disruption of intestinal barrier integrity and functional capacity. Together, we provided the first evidence that COS could protect against intestinal apoptosis through alleviating severe ERS, which may be related to the inhibition of the Akt/mTOR signaling pathway.

Non-functional GoFLA19s are responsible for the male sterility caused by hybrid breakdown in cotton (Gossypium spp.)

Hybrid breakdown (HB) functions as a common reproductive barrier and reduces hybrid fitness in many species, including cotton. However, the related genes and the underlying genetic mechanisms of HB in cotton remain unknown. Here, we found that the photosensitive genetic male sterile line CCRI9106 was a hybrid progeny of Gossypium hirsutum and Gossypium barbadense and probably a product of HB. Fine mapping with F₂ s (CCRI9106 × G. hirsutum/G. barbadense lines) identified a pair of male sterility genes GoFLA19s (encoding fasciclin-like arabinogalactan family protein) located on chromosomes A12 and D12. Crucial variations occurring in the fasciclin-like domain and the arabinogalactan protein domain were predicted to cause the non-functionalization of GbFLA19-D and GhFLA19-A. CRISPR/Cas9-mediated knockout assay confirmed the effects of GhFLA19s on male sterility. Sequence alignment analyses showed that variations in GbFLA19-D and GhFLA19-A likely occurred after the formation of allotetraploid cotton species. GoFLA19s are specifically expressed in anthers and contribute to tapetal development, exine assembly, intine formation, and pollen grain maturation. RNA-sequencing and quantitative reverse transcriptase-polymerase chain reaction analyses illustrated that genes related to these biological processes were significantly downregulated in the mutant. Our research on male sterility genes, GoFLA19s, improves the understanding of the molecular characteristics and evolutionary significance of HB in interspecific hybrid breeding.

Comparison of Thalamus and Basal Ganglia Signs Between Multiple Sclerosis and Primary Angiitis of the Central Nervous System: An Exploratory Study

Based on the symptoms, especially those affecting small vessels, it is difficult to distinguish multiple sclerosis (MS) from primary angiitis of the central nervous system (PACNS). Magnetic resonance imaging (MRI) helps understand the characteristics of deep gray matter lesions (DGML) in MS and PACNS. We aimed to compare the MRI characteristics of thalamus and basal ganglia lesions between relapsing-remitting MS and PACNS. In our study, 49 relapsing-remitting MS patients and 16 PACNS with MRI-confirmed thalamus or basal ganglia lesions were enrolled. Among the DGMLs in basal ganglia, putamen had significantly higher (P = 0.037) involvement in PACNS than in MS. More importantly, larger lesion sizes in thalamus helps to distinguish PACNS (12.4 ± 4.3 mm) from MS (7.9 ± 3.7 mm) (P = 0.006). But using lesions in basal ganglia, researchers were unable to differentiate the two disorders. Presently, our study shows that MRI performances of deep gray matter differ between MS and PACNS.

Sinensetin Reduces Osteoarthritis Pathology in the Tert-Butyl Hydroperoxide-Treated Chondrocytes and the Destabilization of the Medial Meniscus Model Mice via the AMPK/mTOR Signaling Pathway

As a common degenerative disease, osteoarthritis (OA) usually causes disability in the elderly and socioeconomic burden. Previous studies have shown that proper autophagy has a protective effect on OA. Sinensetin (Sin) is a methylated flavonoid derived from citrus fruits. Studies have shown that Sin is a good autophagy inducer and has shown excellent therapeutic effects in a variety of diseases; however, its role in the treatment of OA is not fully understood. This study proved the protective effect of Sin on OA through a series of in vivo and in vitro experiments. In vitro experiments have shown that Sin may inhibit chondrocyte apoptosis induced by tert-butyl hydroperoxide (TBHP); at the same time, it might also inhibit the production of MMP13 and promote the production of aggrecan and collagen II. Mechanism studies have shown that Sin promotes chondrocyte autophagy by activating AMPK/mTOR signaling pathway. On the contrary, inhibition of autophagy can partially abolish the protective effect of Sin on TBHP-treated chondrocytes. In vivo experiments show that Sin may protect against DMM-induced OA pathogenesis. These results provide evidence that Sin serves as a potential candidate for the treatment of OA.

Directional imbalance of Bloch surface waves for ultrasensitive displacement metrology

Precise position sensing and nanoscale optical rulers are important in many applications in nanometrology, gravitational wave detection and quantum technologies. Several implementations of such nanoscale displacement sensors have been recently developed based on interferometers, nanoantennas, optical field singularities and optical skyrmions. Here, we propose a method for ultrasensitive displacement measurements based on the directional imbalance of the excitation of Bloch surface waves by an asymmetric double slit, which have low propagation loss and provide high detected intensity. The directionality of excitation changes dramatically with a sub-nanometric displacement of the illuminating Gaussian beam across the slit and can be used for displacement and refractive index metrology. We demonstrate a theoretical intensity ratio of the BSW excitation in opposite directions exceeding 890, which provides a displacement sensitivity of up to 2.888 nm^-1 with a resolution below 0.5 nm over a 100 nm linearity range. Experimentally, a directional intensity ratio more than 90 has been achieved, with a displacement sensitivity of 0.122 nm^-1 over a 300 nm linearity range, resulting in a resolution below 8 nm for a 600 nm illumination wavelength. The proposed facile configuration may have potential applications in nanometrology and super-resolution microscopy.

β-Hydroxyisovalerylshikonin inhibits IL-1β-induced chondrocyte inflammation via Nrf2 and retards osteoarthritis in mice

Osteoarthritis is a chronic degenerative disease characterized by cartilage destruction. It is the fourth most disabling disease worldwide and is currently incurable. Inflammation and extracellular matrix (ECM) degradation are considered to be substantial reasons for accelerating the progression of OA. β-Hydroxyisoamylshikonin (β-HIVS) is a natural naphthoquinone compound with anti-inflammatory and antioxidant activity. However, the effect of β-HIVS on OA is still unclear. In this study, we found that β-HIVS can down-regulate the expression of NO, PEG2, IL-6, TNF-α, COX-2, and iNOS, suggesting its anti-inflammatory effects in chondrocytes; we also found that β-HIVS may down-regulate the expression of ADAMTS5 and MMP13 and up-regulate the expression of aggrecan and collagen II to inhibit the degradation of ECM. Mechanistically, β-HIVS inhibited the NFκB pathway by activating the Nrf2/HO-1 axis, thereby exerting its anti-inflammatory and inhibitory effects on ECM degradation. In vivo experiments also proved the therapeutic effects of β-HIVS on OA in mice, and Nrf2 is the target of β-HIVS. These findings indicate that β-HIVS may become a new drug for the treatment of OA.

Genome-Wide Identification of the Early Flowering 4 (ELF4) Gene Family in Cotton and Silent GhELF4-1 and GhEFL3-6 Decreased Cotton Stress Resistance

The early flowering 4 (ELF4) family members play multiple roles in the physiological development of plants. ELF4s participated in the plant biological clock's regulation process, photoperiod, hypocotyl elongation, and flowering time. However, the function in the ELF4s gene is barely known. In this study, 11, 12, 21, and 22 ELF4 genes were identified from the genomes of Gossypium arboreum, Gossypium raimondii, Gossypium hirsutum, and Gossypium barbadense, respectively. There ELF4s genes were classified into four subfamilies, and members from the same subfamily show relatively conservative gene structures. The results of gene chromosome location and gene duplication revealed that segmental duplication promotes gene expansion, and the Ka/Ks indicated that the ELF4 gene family has undergone purification selection during long-term evolution. Spatio-temporal expression patterns and qRT-PCR showed that GhELF4 genes were mainly related to flower, leaf, and fiber development. Cis-acting elements analysis and qRT-PCR showed that GhELF4 genes might be involved in the regulation of abscisic acid (ABA) or light pathways. Silencing of GhELF4-1 and GhEFL3-6 significantly affected the height of cotton seedlings and reduced the resistance of cotton. The identification and functional analysis of ELF4 genes in upland cotton provide more candidate genes for genetic modification.

A colorimetric and fluorescence turn-on probe for the detection of ascorbic acid in living cells and beverages

A colorimetric and fluorescence turn-on dual-signal assay was developed for the determination of ascorbic acid (AA). Because the ultraviolet absorption of the oxidized 3,3',5,5'-tetramethylbenzidine (oxTMB) overlapped with the fluorescence emission of glutathione stabilized Au nanoclusters (AuNCs), the fluorescence of AuNCs can be quenched by oxTMB. When AA was added, the blue oxTMB was reduced to colorless TMB, and the fluorescence of AuNCs was restored simultaneously. The decrease in absorbance and increase in fluorescence signal depended on the concentration of AA. In the determination range of 0.5 to 200 μM, the detection limits (LOD) for AA were as low as 0.15 µM and 0.22 µM for fluorometric and colorimetric, respectively. The established probe was used successfully for AA detection in living cells and beverages.

1,25-Dihydroxyvitamin D3 inhibits porcine epidemic diarrhea virus replication by regulating cell cycle resumption in IPEC-J2 porcine epithelial cells

Porcine epidemic diarrhea virus (PEDV) infection causes heavy economic losses in the pig industry. Currently, the lack of effective treatments prompts new antiviral researches. We have shown that 25-hydroxyvitamin D₃ supplementation alleviated PEDV infection in weaned pigs before. However, it is not clear whether vitamin D inhibits PEDV replication. In this study, 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) inhibited PEDV induced mitochondria damage and cell apoptosis. In addition, 1,25(OH)₂D₃ treatment decreased PEDV nucleocapsid gene and protein levels in IPEC-J2 cells. Transcriptomic data showed that PEDV infection altered the expression of 5316 genes (2498 up, 2818 down) in IPEC-J2 cells. The differentially expressed genes were mainly involved in cell cycle process, ribonucleoprotein complex biogenesis, mitotic nuclear division, and other biological processes. Then we examined the effects of PEDV infection on cell cycle progression in IPEC-J2 cells, and the results showed that PEDV induced G0/G1 phase arrest. G0/G1-phase arrest was also conducive to PEDV replication. However, 1,25(OH)₂D₃ treatment decreased G0/G1 phase percentage induced by PEDV. Cyclin D and cyclin E mRNA expression were also increased by 1,25(OH)₂D₃ supplementation upon PEDV infection. Moreover, the regulation of 1,25(OH)₂D₃ on cell cycle progression was abrogated by ERK1/2 inhibitor, as well as the mRNA expression of cyclin D. The inhibition of 1,25(OH)₂D₃ on PEDV replication was also eliminated by ERK1/2 inhibitor. Taken together, these results demonstrated that 1,25(OH)₂D₃ supplementation inhibited PEDV replication, and the anti-virus effect of 1,25(OH)₂D₃ was mediated in part by regulating cell cycle progression through ERK1/2 signaling pathway.

Hydrogen sulfide protects against IL-1β-induced inflammation and mitochondrial dysfunction-related apoptosis in chondrocytes and ameliorates osteoarthritis

The inflammatory environment and excessive chondrocyte apoptosis have been demonstrated to play crucial roles in the onset of osteoarthritis (OA). Hydrogen sulfide (H2 S), a gaseous signalling molecule, exerts an inhibitory effect on inflammation and apoptosis in several degenerative diseases. However, the protective effect of H2 S against OA has not been fully clarified, and its underlying mechanism should be examined further. In the current study, the role of endogenous H2 S in the pathogenesis of OA and its protective effects on interleukin (IL)-1β-induced chondrocytes were identified. Our data revealed decreased H2 S expression in both human degenerative OA cartilage tissue and IL-1β-induced chondrocytes. Pretreatment with the H2 S donor sodium hydrosulfide (NaHS) dramatically attenuated IL-1β-induced overproduction of inflammatory cytokines and improved the balance between anabolic and catabolic chondrocyte capacities, and these effects were dependent on PI3K/AKT pathway-mediated inhibition of nuclear factor kappa B (NF-κB). Moreover, mitochondrial dysfunction-related apoptosis was significantly reversed by NaHS in IL-1β-stimulated chondrocytes. Mechanistically, NaHS partially suppressed IL-1β-induced phosphorylation of the mitogen-activated protein kinase (MAPK) cascades. Furthermore, in the destabilization of the medial meniscus mouse model, OA progression was ameliorated by NaHS administration. Taken together, these results suggest that H2 S may antagonize IL-1β-induced inflammation and mitochondrial dysfunction-related apoptosis via selective suppression of the PI3K/Akt/NF-κB and MAPK signalling pathways, respectively, in chondrocytes and may be a potential therapeutic agent for the treatment of OA.

The SOC1-like gene BoMADS50 is associated with the flowering of Bambusa oldhamii

Bamboo is known for its edible shoots and beautiful texture and has considerable economic and ornamental value. Unique among traditional flowering plants, many bamboo plants undergo extensive synchronized flowering followed by large-scale death, seriously affecting the productivity and application of bamboo forests. To date, the molecular mechanism of bamboo flowering characteristics has remained unknown. In this study, a SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1)-like gene, BoMADS50, was identified from Bambusa oldhamii. BoMADS50 was highly expressed in mature leaves and the floral primordium formation period during B. oldhamii flowering and overexpression of BoMADS50 caused early flowering in transgenic rice. Moreover, BoMADS50 could interact with APETALA1/FRUITFULL (AP1/FUL)-like proteins (BoMADS14-1/2, BoMADS15-1/2) in vivo, and the expression of BoMADS50 was significantly promoted by BoMADS14-1, further indicating a synergistic effect between BoMADS50 and BoAP1/FUL-like proteins in regulating B. oldhamii flowering. We also identified four additional transcripts of BoMADS50 (BoMADS50-1/2/3/4) with different nucleotide variations. Although the protein-CDS were polymorphic, they had flowering activation functions similar to those of BoMADS50. Yeast one-hybrid and transient expression assays subsequently showed that both BoMADS50 and BoMADS50-1 bind to the promoter fragment of itself and the SHORT VEGETATIVE PHASE (SVP)-like gene BoSVP, but only BoMADS50-1 can positively induce their transcription. Therefore, nucleotide variations likely endow BoMADS50-1 with strong regulatory activity. Thus, BoMADS50 and BoMADS50-1/2/3/4 are probably important positive flowering regulators in B. oldhamii. Moreover, the functional conservatism and specificity of BoMADS50 and BoMADS50-1 might be related to the synchronized and sporadic flowering characteristics of B. oldhamii.

Adsorption and diffusion of alkali metals (Li, Na, and K) on heteroatom-doped monolayer titanium disulfide

Doping engineering is an effective modification strategy to enhance the electrochemical performance of electrode materials. In this paper, the impacts of heteroatom doping in monolayer titanium disulfide (TiS2) by substituting the S atom with the heteroatoms (B, C, N, O, F, and P) on the adsorption and diffusion capabilities of alkali metals (Li, Na, and K) have been systematically investigated using first-principles calculations to evaluate the material performance for application in alkali metal-ion batteries. The doping of most heteroatoms can promote the adsorption capability of alkali metal atoms on monolayer TiS2 as their adsorption energies decrease compared with the pristine system, particularly for p-type doping with C, N, and P. The diffusion energy barriers decrease when alkali metals approach the doping site of most heteroatom-doped TiS2, and the barriers near the doping site are extremely small (0.00-0.08 eV), whereas they slightly increase as alkali metals move away from the doping site. P doping has the lowest overall diffusion energy barrier for each metal. Thus, monolayer TiS2 with heteroatom doping, especially P doping, can be used as a potential anode material for alkali metal-ion batteries. This study can help comprehend the impacts of heteroatom doping and design high-performance electrode materials for rechargeable batteries.

GhGPAT12/25 Are Essential for the Formation of Anther Cuticle and Pollen Exine in Cotton (Gossypium hirsutum L.)

Glycerol-3-phosphate acyltransferases (GPATs), critical for multiple biological processes like male fertility, have been extensively characterized. However, their precise functions and underlying regulatory mechanism in cotton anther development are unclear. This research demonstrated the importance of GhGPAT12/25 (a paralogs pair on A12/D12 sub-chromosome of cotton) to regulate the degradation of tapetum, anther cuticle formation, and pollen exine development. GhGPAT12 and GhGPAT25 exhibited specifically detected transcripts in tapetum and pollen exine during the early anther developmental stages. GhGPAT12/25 are sn-2 glycerol-3-phosphate acyltransferases and can transfer the acyl group of palmitoyl-CoA to glycerol-3-phosphate (G3P). CRISPR/Cas9-mediated knockout identified the functional redundancy of GhGPAT12 and GhGPAT25. Knockout of both genes caused completely male sterility associated with abnormal anther cuticle, swollen tapetum, and inviable microspores with defective exine and irregular unrestricted shape. RNA-seq analysis showed that the loss of function of GhGPAT12/25 affects the processes of wax metabolic, glycerol monomer biosynthesis, and transport. Consistently, cuticular waxes were dramatically reduced in mutant anthers. Yeast one-hybrid system (Y1H), virus-induced gene silencing (VIGS), and dual-luciferase (LUC) assays illustrated that GhMYB80s are likely to directly activate the expression of GhGPAT12/25. This study provides important insights for revealing the regulatory mechanism underlying anther development in cotton.