[Advances on cyclopeptides of plants].

Cyclopeptides isolated from a variety of plants are a class of cyclic nitrogen-containing compounds, and they are primarily formed by peptide bonds between amino acids, generally containing 2 to 37 L-configuration encoded or non-encoded amino acid residues. Cyclopeptides have significant values in scientific research as natural small-molecule metabolites produced by plants. The available studies have revealed that such natural products are ubiquitous in plants, which mainly include cyclic dipeptides, cyclic tetrapeptides, cyclic pentapeptides, cyclic hexapeptides, cyclic heptapeptides, cyclic octapeptides, cyclic nonapeptides, and cyclic decapeptides. Among them, cyclic dipeptides, cyclic hexapeptides, and cyclic octapeptides are the major active compounds. It has been reported that plant cyclopeptides have novel and unique chemical structures. They possess diverse pharmacological activities, such as antineoplastic, antimicrobial, antimalarial, anti-inflammatory, and antiviral activities. This paper summarizes the research achievements of plant cyclopeptides since 2006, aiming to provide theoretical reference for the research and application of plant cyclopeptides in medicine, health, and agriculture fields.

Reverse dorsolateral proximal phalangeal island flap: Long-term results.

OBJECTIVES: This study aims to present long-term follow-up results of the reverse dorsolateral proximal phalangeal island flap designed for reconstruction of large fingertip and pulp defects. METHODS: We examined 18 patients who underwent reverse dorsolateral proximal phalangeal island flap surgery to address ≥2.5 cm fingertip and pulp defects. Mean follow-up was 84.4 months. Sensitivity assessments were conducted using the Semmes-Weinstein monofilament and 2-point discrimination tests. Additionally, we evaluated finger joint active range of motion, complications and cold intolerance. RESULTS: Mild venous congestion was observed in 5 flaps. Significant differences were observed in 2-point discrimination and Semmes-Weinstein monofilament tests between the injured and contralateral sides, specifically in the flaps, the dorsal side of the middle phalanx, and the donor site. The flap's mean static 2-point discrimination was 8.3 mm. Restricted distal interphalangeal joint extension was observed in 2 cases. Total active motion with the flap was good or excellent in the injured fingers, but with a significant difference between injured and contralateral fingers. Additionally, 42% of the injured fingers exhibited hook nail deformity, and 2 patients reported cold intolerance. Despite these issues, most patients has high scores for the appearance and satisfaction aspects of the Michigan Hand Outcomes Questionnaire. CONCLUSION: In moderate or larger fingertip defects, the reverse dorsolateral proximal phalangeal island flap serves as an alternative for reconstructing both fingertip and pulp issues. However, this option involves sacrificing some sensation in the dorsum of the middle phalangeal finger and the donor area. LEVEL OF EVIDENCE: IV, therapeutic study.

A Novel Multi-Functional Fluorescence Probe for the Detection of Al3+/Zn2+/Cd2+ and its Practical Applications.

A novel multi-functional fluorescence probe HMIC based on hydrazide Schiff base has been successfully synthesized and characterized. It can distinguish Al3+/Zn2+/Cd2+ in ethanol, in which fluorescence emission with different colors (blue for Al3+, orange for Zn2+, and green for Cd2+) were presented. The limits of detection of HMIC towards three ions were calculated from the titration curve as 7.70 × 10- 9 M, 4.64 × 10- 9 M, and 1.35 × 10- 8 M, respectively. The structures of HMIC and its complexes were investigated using UV-Vis spectra, Job's plot, infrared spectra, mass spectrometry, 1H-NMR and DFT calculations. Practical application studies have also demonstrated that HMIC can be applied to real samples with a low impact of potential interferents. Cytotoxicity and cellular imaging assays have shown that HMIC has good cellular permeability and potential antitumor effects. Interestingly, HMIC can image Al3+, Zn2+ and Cd2+ in the cells with different fluorescence signals.

Sulfasalazine ameliorates lipopolysaccharide-induced acute lung injury by inhibiting oxidative stress and nuclear factor-kappaB pathways.

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) has a high mortality rate and incidence of complications. The pathophysiology of ALI/ARDS is still not fully understood. The lipopolysaccharide (LPS)-induced mouse model of ALI has been widely used to study human ALI/ARDS. Sulfasalazine (SASP) has antibacterial and anti-inflammatory effects and is used for treating inflammatory bowel and rheumatic diseases. However, the effect of SASP on LPS-induced ALI in mice has not yet been reported. Therefore, we aimed to investigate the effect of SASP on LPS-induced ALI in mice. Mice were intraperitoneally injected with SASP 2 h before or 4 h after LPS modeling. Pulmonary pathological damage was measured based on inflammatory factor expression (malondialdehyde and superoxide dismutase levels) in the lung tissue homogenate and alveolar lavage fluid. The production of inflammatory cytokines and occurrence of oxidative stress in the lungs induced by LPS were significantly mitigated after the prophylactic and long-term therapeutic administration of SASP, which ameliorated ALI caused by LPS. SASP reduced both the production of inflammatory cytokines and occurrence of oxidative stress in RAW264.7 cells, which respond to LPS. Moreover, its mechanism contributed to the suppression of NF-κB and nuclear translocation. In summary, SASP treatment ameliorates LPS-induced ALI by mediating anti-inflammatory and antioxidant effects, which may be attributed to the inhibition of NF-κB activation and promotion of antioxidant defenses. Thus, SASP may be a promising pharmacologic agent for ALI therapy.

Effect of lorecivivint on osteoarthritis: A systematic review and meta-analysis.

Objective: To comprehensively evaluate the effectiveness and safety of lorecivivint inhibitors in the treatment of osteoarthritis through meta-analysis. Methods: A comprehensive literature search on lorecivivint inhibitors in osteoarthritis was performed using electronic databases such as PubMed, Embase, Web of Science, and CochraneLibrary up to July 30, 2022. Two reviewers independently screened, evaluated, and reviewed the eligible studies. Data analysis and processing were carried out using RevMan 5.4 software. Results: A total of six studies involving 3056 participants were included. Meta-analysis showed that compared with the control group, lorecivivint significantly increased WOMAC discomfort (0.03 mg Week 12) (MD = -0.21, 95% CI [-1.94 - 1.53]; P = 0.81), WOMAC function (0.07 mg Week 24) (MD = -1.81, 95% CI [-4.74 - 1.12]; P = 0.23) and Joint space width (0.23 mg Week 24) (MD = -1.16, 95% CI [-3.69 - 1.38]; P = 0.37). Conclusion: A new treatment method combining Wnt pathway modulators with intra-articular CLK2/DYRK1A inhibitors could be a promising therapy for treating osteoarthritis. Lorecivivint was found to significantly improve WOMAC discomfort, WOMAC function, and joint space width in osteoarthritis patients. It is anticipated to be a reliable, safe, and effective treatment option for osteoarthritis with significant therapeutic utility and potential applications.

Culture and identification of neonatal rat brain-derived neural stem cells.

BACKGROUND: Timing of passaging, passage number, passaging approaches and methods for cell identification are critical factors influencing the quality of neural stem cells (NSCs) culture. How to effectively culture and identify NSCs is a continuous interest in NSCs study while these factors are comprehensively considered. AIM: To establish a simplified and efficient method for culture and identification of neonatal rat brain-derived NSCs. METHODS: First, curved tip operating scissors were used to dissect brain tissues from new born rats (2 to 3 d) and the brain tissues were cut into approximately 1 mm3 sections. Filter the single cell suspension through a nylon mesh (200-mesh) and culture the sections in suspensions. Passaging was conducted with TrypLTM Express combined with mechanical tapping and pipetting techniques. Second, identify the 5th generation of passaged NSCs as well as the revived NSCs from cryopreservation. BrdU incorporation method was used to detect self-renew and proliferation capabilities of cells. Different NSCs specific antibodies (anti-nestin, NF200, NSE and GFAP antibodies) were used to identify NSCs specific surface markers and muti-differentiation capabilities by immunofluorescence staining. RESULTS: Brain derived cells from newborn rats (2 to 3 d) proliferate and aggregate into spherical-shaped clusters with sustained continuous and stable passaging. When BrdU was incorporated into the 5th generation of passaged cells, positive BrdU cells and nestin cells were observed by immunofluorescence staining. After induction of dissociation using 5% fetal bovine serum, positive NF200, NSE and GFAP cells were observed by immunofluorescence staining. CONCLUSION: This is a simplified and efficient method for neonatal rat brain-derived neural stem cell culture and identification.

Analysis of leaf forage value and screening of different populations of Pteroceltis tatarinowii, a rare and endemic species in China.

To fully exploit the economic value of the Chinese endemic species Pteroceltis tatarinowii and provide new resources for forage production, the forage nutritional value of P. tatarinowii leaves from different populations was analyzed and evaluated. The results were as follows: 1) There were significant differences in the forage nutrient indices of leaves from different populations. The crude protein content was 10.77%-18.65%, with an average of 14.58%, and the SDJN population had the highest crude protein content. The average crude fat, crude fiber content was 7.62%; the average neutral detergent fiber content was 25.33%; and the average acid detergent fiber contents were 6.79%, 7.62%, 25.33%, and 17.52%, respectively. The average phosphorus and calcium content in the leaves was 0.785 g·kg-1 and 58.01 g·kg-1, respectively. The tannin content was much lower than the antifeedant standard, at an average of 4.97 g·kg-1. The average total amounts of hydrolyzed and free amino acids in the leaves were 108.20 mg·g-1 and 47.87 mg·g-1, respectively. Thus, P. tatarinowii leaves have high crude protein, crude fat, and calcium contents, and low fiber, tannin contents, and are protein-rich. These results provide evidence that this species can be developed into an excellent woody forage tree. 2) There were significant differences in the forage quality evaluation indices among the populations. The forage indices of NDP, ADP, DMI, DDM, and RFV of 21 populations all met the super standard of the American Grass and Grassland Association (AFGC) for hay, two crude protein indices met the grade 1 standard, and 12 crude protein indices met the grade 2 standard. Four high-protein and high-RFV forage populations (SDJN, SDZZ, SXLQ, and AHXX) were selected. 3) The results of the correlation analysis showed that there was no significant correlation between the forage characteristics of P. tatarinowii leaves and latitude and longitude, indicating no significant geographical variation. However, the forage characteristics were strongly correlated with elevation, average annual temperature, and annual precipitation. Thus, high elevation, low temperatures, and rainy weather can improve the forage value of the leaves. P. tatarinowii can be planted to provide leaf forage in cold and wet areas at a specific elevation. Moreover, the forage value of P. tatarinowii leaves can be further improved by increasing nitrogen fertilizer and reducing K and Ca fertilizers during cultivation. 4) Cluster analysis revealed obvious regionalism. Taking the Yangtze River Basin as the limit, cluster analysis divided the species into four population groups: the Yangtze River Basin and northern, southwestern, and eastern coastal populations.

A diagnostic model for differentiating tuberculous spondylitis from pyogenic spondylitis: a retrospective case-control study.

The purpose of this study was to describe and compare the clinical data, laboratory examination and imaging examination of tuberculous spondylitis (TS) and pyogenic spondylitis (PS), and to provide ideas for diagnosis and treatment intervention. The patients with TS or PS diagnosed by pathology who first occurred in our hospital from September 2018 to November 2021 were studied retrospectively. The clinical data, laboratory results and imaging findings of the two groups were analyzed and compared. The diagnostic model was constructed by binary logistic regression. In addition, an external validation group was used to verify the effectiveness of the diagnostic model. A total of 112 patients were included, including 65 cases of TS with an average age of 49 ± 15 years, 47 cases of PS with an average of 56 ± 10 years. The PS group had a significantly older age than the TS group (P = 0.005). In laboratory examination, there were significant differences in WBC, neutrophil (N), lymphocyte (L), ESR, CRP, fibrinogen (FIB), serum albumin (A) and sodium (Na). The difference was also statistically significant in the comparison of imaging examinations at epidural abscesses, paravertebral abscesses, spinal cord compression, involvement of cervical, lumbar and thoracic vertebrae. This study constructed a diagnostic model, which was Y (value of TS > 0.5, value of PS < 0.5) = 1.251 * X1 (thoracic vertebrae involved = 1, thoracic vertebrae uninvolved = 0) + 2.021 * X2 (paravertebral abscesses = 1, no paravertebral abscess = 0) + 2.432 * X3 (spinal cord compression = 1, no spinal cord compression = 0) + 0.18 * X4 (value of serum A)-4.209 * X5 (cervical vertebrae involved = 1, cervical vertebrae uninvolved = 0)-0.02 * X6 (value of ESR)-0.806 * X7 (value of FIB)-3.36. Furthermore, the diagnostic model was validated using an external validation group, indicating a certain value in diagnosing TS and PS. This study puts forward a diagnostic model for the diagnosis of TS and PS in spinal infection for the first time, which has potential guiding value in the diagnosis of them and provides a certain reference for clinical work.

Burnout and job stress of anesthesiologists in the tertiary class A hospitals in Northwest China: A cross-sectional design.

Purpose: Our purpose was to assess job stress and burnout among anesthesiologists in the tertiary class A hospitals in Northwest China, analyze the possible causes and adverse consequences of increased job stress and burnout of anesthesiologists in this region, and put forward suggestions in combination with the current national policies. Methods: We sent 500 electronic questionnaires to all anesthesiologists practicing in the tertiary class A hospitals in Northwest China from 1960 to 2017 on April 2020. A total of 336 (67.2%) questionnaires were returned and could be used for analysis. Burnout and job stress were assessed by using the modified Maslach Burnout Inventory-Human Services Survey and Chinese Perceived Stress Scale, respectively. Results: First, as for emotional exhaustion, the situations of anesthesiologists with different working years and workloads are different with statistical significance (P < 0.05). Second, as for depersonalization, the situations of anesthesiologists with different ages, professional titles, working years, physical health status, and workload are different (P < 0.05). Third, as for personal accomplishment, the situations of anesthesiologists with different physical health status are different (P < 0.05). Finally, the regression results showed that the longer the fatigue working years and the worse the physical health of anesthesiologists in Northwest China, the more likely these two factors were to cause burnout (P < 0.05), as for job stress, there was a negative correlation between job stress and physical health status (P < 0.05). Conclusion: Burnout and high job pressure are common among anesthesiologists in tertiary class A hospitals in Northwest China. We should focus on the allocation of labor intensity, pay attention to the physical and mental health of employees, establish targeted incentive mechanism, and improve the system of promotion and income rises for grassroots doctors. This may be not only conducive to the quality of medical care for patients but also conducive to the development of anesthesiology in China. Trial registration: Identifier: ChiCTR2000031316.

M2 Macrophage Membrane-Mediated Biomimetic-Nanoparticle Carrying COX-siRNA Targeted Delivery for Prevention of Tendon Adhesions by Inhibiting Inflammation.

Tendon adhesion is the most common outcome of tendon or tendon-to-bone healing after injury. Our group developed a hydrogel-nanoparticle sustained-release system previously to inhibit cyclooxygenases (COXs) expression and consequently prevent tendon adhesion and achieved satisfactory results. However, effective treatment of multiple tendon adhesions is always a challenge in research on the prevention of tendon adhesion. In the present study, an M2M@PLGA/COX-siRNA delivery system is successfully constructed using the cell membranes of M2 macrophages and poly (lactic-co-glycolic acid) (PLGA) nanoparticles. Targeting properties and therapeutic effects are observed in mice or rat models of flexor digitorum longus (FDL) tendon injury combined with rotator cuff injury. The results showed that the M2M@PLGA/COX-siRNA delivery system has low toxicity and remarkable targeting properties to the injured areas. Treatment with the M2M@PLGA/COX-siRNA delivery system reduced the inflammatory reaction and significantly improved tendon adhesion in both the FDL tendon and rotator cuff tissues. These findings indicate that the M2M@PLGA delivery system can provide an effective biological strategy for preventing multiple tendon adhesions.

Ratiometric detection of I- using a dysprosium-based metal-organic framework with a single emission center.

In this study, a dysprosium-based metal-organic framework (MOF) sensor (Dy-MOF) was developed for the ratiometric detection of I- in aqueous medium. Upon excitation at 230 nm, Dy-MOF shows two dominant emission bands at 464 nm and 574 nm assigned to (4F, 4D)5/2 → 6H9/2 + 6F11/2 and 4F9/2 → 6H13/2 transition of Dy3+, respectively, which have different sensitivities toward iodide ions. The introduction of I- slightly weakened the blue emission at 464 nm and significantly quenched the yellow emission at 574 nm. Thus, ratiometric sensing for iodide was realized using the yellow-to-blue intensity ratio of Dy3+. Dy-MOF exhibits superior sensing behavior towards I- with high selectivity, sensitivity and low detection limit (24 nM). This study also provides a strategy for the construction of a ratiometric sensor with dual-emission bands originating from only one emission center.

Optimization of CRISPR-Cas system for clinical cancer therapy.

Cancer is a genetic disease caused by alterations in genome and epigenome and is one of the leading causes for death worldwide. The exploration of disease development and therapeutic strategies at the genetic level have become the key to the treatment of cancer and other genetic diseases. The functional analysis of genes and mutations has been slow and laborious. Therefore, there is an urgent need for alternative approaches to improve the current status of cancer research. Gene editing technologies provide technical support for efficient gene disruption and modification in vivo and in vitro, in particular the use of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas systems. Currently, the applications of CRISPR-Cas systems in cancer rely on different Cas effector proteins and the design of guide RNAs. Furthermore, effective vector delivery must be met for the CRISPR-Cas systems to enter human clinical trials. In this review article, we describe the mechanism of the CRISPR-Cas systems and highlight the applications of class II Cas effector proteins. We also propose a synthetic biology approach to modify the CRISPR-Cas systems, and summarize various delivery approaches facilitating the clinical application of the CRISPR-Cas systems. By modifying the CRISPR-Cas system and optimizing its in vivo delivery, promising and effective treatments for cancers using the CRISPR-Cas system are emerging.

A ratiometric luminescence sensing platform based on lanthanide-based silica nanoparticles for selective and sensitive detection of Fe3+ and Cu2+ ions.

Detection of Fe(III) and Cu(II) in water is highly desirable because their abnormal levels can cause serious harm to human health and environmental safety. In this work, a ratiometric luminescence sensing platform based on lanthanide-based silica nanoparticles was constructed for the detection of Fe3+ and Cu2+ ions. The terbium-silica nanoparticles (named SiO2@Tb) with dual-emission signals were successfully prepared by grafting Tb3+ ions onto trimellitic anhydride (TMA) functionalized silica nanospheres. It can serve as a ratiometric fluorescent probe for the detection of Fe3+ and Cu2+ ions in water with the green emission of Tb3+ ions as a response signal and the blue emission of silica nanospheres as the reference signal. Significantly, an easy-to-differentiate color change for visual detection was also realized. SiO2@Tb shows high sensitivity even in very low concentration regions towards the sensing of Fe3+ and Cu2+ with low detection limits of 0.75 µM and 0.91 µM, respectively. Moreover, the mechanism for the luminescence quenching of SiO2@Tb was systematically investigated, and was attributed to the synergetic effect of the absorption competition quenching (ACQ) mechanism and cation exchange. This study demonstrates that SiO2@Tb can be employed as a promising fluorescent probe for the detection of Fe3+ and Cu2+ ions, and the combination of lanthanide ions with silica nanoparticles is an effective strategy to construct a ratiometric fluorescent sensing platform for the determination of analytes in environmental detection.

Effect of vitamin E supplementation in rheumatoid arthritis: a systematic review and meta-analysis.

OBJECTIVE: The purpose of this study was to evaluate the safety and effectiveness of vitamin E in rheumatoid arthritis patients. METHODS: A computerized search of PubMed, Embase, The Cochrane Library, and Web of Science databases was conducted to find published randomized controlled trials of vitamin E in rheumatoid arthritis; the experimental group was treated with vitamin E, while the control group was treated with placebo, other drugs, or external therapy; the search period was from the time each database was established to December 31, 2021, and a meta-analysis was conducted using Rev Man 5.4 software. RESULTS: This research eventually comprised nine publications with a total of 39,845 patients. Vitamin E supplementation was shown to be more effective in individuals with RA for sensitive joints (MD = -1.66, 95% CI - -6.32-2.99; I2 = 93%; P < 0.00001) and swollen joints (MD = -0.46, 95% CI - -1.98-1.07; I2 = 56%; P = 0.08). CONCLUSIONS: Vitamin E's ability to restore the intestinal barrier and improve the gastrointestinal tract may be linked to the prevention and treatment of rheumatoid arthritis. Vitamin E supplements used on a regular basis can help individuals with RA reduce joint discomfort, edema, and stiffness, as well as enhance their overall quality of life.

Will previous antimicrobial therapy reduce the positivity rate of metagenomic next-generation sequencing in periprosthetic joint infections? A clinical study.

Background: Metagenomic next-generation sequencing (mNGS) is a culture-independent massively parallel DNA sequencing technology and it has been widely used for rapid etiological diagnosis with significantly high positivity rate. Currently, clinical studies on evaluating the influence of previous antimicrobial therapy on positivity rate of mNGS in PJIs are rarely reported. The present study aimed to investigate whether the positivity rate of mNGS is susceptible to previous antimicrobial therapy. Methods: We performed a prospective trial among patients who undergone hip or knee surgery due to periprosthetic joint infection (PJI) to compare the positivity rate of culture and mNGS between cases with and without previous antimicrobial therapy, and the positivity rates between cases with different antimicrobial-free intervals were also analysed. Results: Among 131 included PJIs, 91 (69.5%) had positive cultures and 115 (87.8%) had positive mNGS results. There was no significant difference in the positivity rate of deep-tissue culture and synovial fluid mNGS between cases with and without previous antimicrobial therapy. The positivity rate of synovial fluid culture was higher in cases with previous antimicrobial therapy. The positivity rates of mNGS in synovial fluid decreased as the antimicrobial-free interval ranged from 4 to 14 days to 0 to 3 days. Conclusion: mNGS is more advantageous than culture with a higher pathogen detection rate. However, our data suggested that antimicrobial agents may need to be discontinued more than 3 days before sampling to further increase the positivity rate of mNGS for PJIs.

Abnormalities of the Halogen Bonds in the Complexes between Y2CTe (Y = H, F, CH3) and XF (X = F, Cl, Br, I).

In this work, the hydrogen bonds and halogen bonds in the complexes between Y2CTe (Y = H, F, CH3) and XF (X = F, Cl, Br, I) have been studied by quantum chemical calculations. We found three interesting abnormalities regarding the interactions. Firstly, the strength of halogen bonds increases in the order of IF < BrF < ClF < F2. Secondly, the halogen bonds formed by F2 are very strong, with an interaction energy in the range between −199.8 and −233.1 kJ/mol. Thirdly, all the halogen bonds are stronger than the hydrogen bonds in the systems we examined. All these results are against the general understanding of halogen bonds. These apparent abnormal properties are reconciled with the high polarizability of the Te atom and the strong inducing effect of F on the Te atom of Y2CTe. These findings provide a new perspective on halogen bonds. Additionally, we also proposed bonding distance-based methods to compare the strength of halogen/hydrogen bonds formed between different donor atoms and the same acceptor atom.

Targeted pharmacokinetics and bioinformatics screening strategy reveals JAK2 as the main target for Xin-Ji-Er-Kang in treatment of MIR injury.

BACKGROUND AND PURPOSE: Xin-Ji-Er-Kang (XJEK) is traditional Chinese formula presented excellent protective effects on several heart diseases, but the potential components and targets are still unclear. The aim of this study is to elucidate the effective components of XJEK and reveal its potential mechanism of cardioprotective effect in myocardial ischemia-reperfusion (MIR) injury. EXPERIMENTAL APPROACH: Firstly, the key compounds in XJEK, plasma and heart tissue were analyzed by high resolution mass spectrometry. Bioinformatics studies were also involved to disclose the potential targets and the binding sites for the key compounds. Secondly, to study the protective effect of XJEK on MIR injury and related mechanism, mice subjected to MIR surgery and gavage administered with XJEK for 6 weeks. Cardiac function parameters and apoptosis level of cardiac tissue were assessed. The potential mechanism was further verified by knock down of target protein in vitro. RESULTS: Pharmacokinetics studies showed that Sophora flavescens alkaloids, primarily composed with matrine, are the key component of XJEK. And, through bioinformatic analysis, we speculated JAK2 could be the potential target for XJEK, and could form stable hydrogen bonds with matrine. Administration of XJEK and matrine significantly improved heart function and reduced apoptosis of cardiomyocytes by increasing the phosphorylation of JAK2 and STAT3. The anti-apoptosis effect of XJEK and matrine was also observed on AC16 cells, and could be reversed by co-treatment with JAK2 inhibitor AG490 or knock-down of JAK2. CONCLUSION: XJEK exerts cardioprotective effect on MIR injury, which may be associated with the activation of JAK2/STAT3 signaling pathway.

Comparative Analysis of the Metabolome and Transcriptome between the Green and Yellow-Green Regions of Variegated Leaves in a Mutant Variety of the Tree Species Pteroceltis tatarinowii.

In nature, many different factors cause plants to develop variegated leaves. To explore the mechanism of variegated leaf formation in Pteroceltis tatarinowii, a mutant variety ('Jinyuyuan'), which was induced by ethylmethylsulfone, was selected, and its morphological structure, physiology, biochemistry, transcription and metabolism were analysed. According to differences in colour values, the colours were divided into two regions: a green region and a yellow-green region. The chlorophyll content of the two regions was significantly different. Moreover, the yellow-green regions of the leaves were significantly thinner than the green regions. The chloroplast ultrastructure in the yellow-green region revealed small chloroplasts, large vacuoles, small starch grains, obviously increased numbers of osmophilic grains, loose lamellae of the inner capsule and thin lamellae. Moreover, the yellow-green region was accompanied by oxidative stress, and the activity of the oxidative phosphorylation pathway related to oxidative activity in the transcriptome showed an upward trend. Vitamin B6 and proline contents also increased, indicating that the antioxidant activity of cells in the yellow-green region increased. Transcriptomic and metabolomic analysis showed that the differentially expressed genes (DEGs) related to chlorophyll synthesis and metabolism led to a decrease in the photosynthesis and then a decrease in the assimilation ability and contents of sucrose, starch and other assimilates. Amino acid synthesis and metabolism, lipid synthesis and the activity of metabolic pathways were obviously downregulated, and the contents of differentially accumulated metabolites associated with amino acids and lipids were also reduced. At the same time, 31 out of 32 DEGs involved in the flavonoid synthesis pathway were downregulated, which affected leaf colour. We hypothesized that the variegated leaves of P. tatarinowii 'Jinyuyuan' are caused by transcriptional and post-transcriptional regulation. Mutations in pigment and flavonoid synthesis pathway genes and transcription factor genes directly affect both pigment and flavonoid synthesis and degradation rate, which in turn affect carbon assimilation, carbon fixation, related protein synthesis and enzyme activity, lipid synthesis and degradation and the activity of other metabolic pathways, eventually leading to the formation of different colour regions.

Diffraction gratings based on a multilayer silicon nitride waveguide with high upward efficiency and large effective length.

Diffraction gratings with high upward diffraction efficiency and large effective length are required for chip-scale light detection and ranging. We propose a diffraction grating based on a multilayer silicon nitride waveguide, which theoretically achieves an upward diffraction efficiency of 92%, a near-field effective length of 376 µm, and a far-field divergence angle of 0.105° at a wavelength of 850 nm. The diffraction grating has a high tolerance to process variations based on Monte Carlo analysis. When the conditions are ±5% layer thickness variation, ±50nm lithographic variation, and ±20nm wavelength drift, more than 71% of the grating samples have a diffraction efficiency higher than 80%, and 100% of the samples have an effective length larger than 200 µm (corresponding to a far-field divergence <0.2∘). Furthermore, the near-field effective length of the grating with an upward diffraction efficiency above 90% can be adjusted from hundreds of microns to centimeters by changing the etching layer thickness and the grating duty cycle. This diffraction grating has a potential application in optical sensing and imaging from visible to near-IR wavelengths.