The relationship between atmospheric particulate matter, leaf surface microstructure, and the phyllosphere microbial diversity of Ulmus L.

BACKGROUND: Plants can retain atmospheric particulate matter (PM) through their unique foliar microstructures, which has a profound impact on the phyllosphere microbial communities. Yet, the underlying mechanisms linking atmospheric particulate matter (PM) retention by foliar microstructures to variations in the phyllosphere microbial communities remain a mystery. In this study, we conducted a field experiment with ten Ulmus lines. A series of analytical techniques, including scanning electron microscopy, atomic force microscopy, and high-throughput amplicon sequencing, were applied to examine the relationship between foliar surface microstructures, PM retention, and phyllosphere microbial diversity of Ulmus L. RESULTS: We characterized the leaf microstructures across the ten Ulmus lines. Chun exhibited a highly undulated abaxial surface and dense stomatal distribution. Langya and Xingshan possessed dense abaxial trichomes, while Lieye, Zuiweng, and Daguo had sparsely distributed, short abaxial trichomes. Duomai, Qingyun, and Lang were characterized by sparse stomata and flat abaxial surfaces, whereas Jinye had sparsely distributed but extensive stomata. The mean leaf retention values for total suspended particulate (TSP), PM2.5, PM2.5-10, PM10-100, and PM> 100 were 135.76, 6.60, 20.10, 90.98, and 13.08 µg·cm- 2, respectively. Trichomes substantially contributed to PM2.5 retention, while larger undulations enhanced PM2.5-10 retention, as evidenced by positive correlations between PM2.5 and abaxial trichome density and between PM2.5-10 and the adaxial raw microroughness values. Phyllosphere microbial diversity patterns varied among lines, with bacteria dominated by Sediminibacterium and fungi by Mycosphaerella, Alternaria, and Cladosporium. Redundancy analysis confirmed that dense leaf trichomes facilitated the capture of PM2.5-associated fungi, while bacteria were less impacted by PM and struggled to adhere to leaf microstructures. Long and dense trichomes provided ideal microhabitats for retaining PM-borne microbes, as evidenced by positive feedback loops between PM2.5, trichome characteristics, and the relative abundances of microorganisms like Trichoderma and Aspergillus. CONCLUSIONS: Based on our findings, a three-factor network profile was constructed, which provides a foundation for further exploration into how different plants retain PM through foliar microstructures, thereby impacting phyllosphere microbial communities.

Effects of selenium enrichment on fermentation characteristics, selenium content and microbial community of alfalfa silage.

BACKGROUND: Selenium is essential for livestock and human health. The traditional way of adding selenium to livestock diets has limitations, and there is a growing trend to provide livestock with a safe and efficient source of selenium through selenium-enriched pasture. Therefore, this study was conducted to investigate the effects of selenium enrichment on fermentation characteristics, selenium content, selenium morphology, microbial community and in vitro digestion of silage alfalfa by using unenriched (CK) and selenium-enriched (Se) alfalfa as raw material for silage. RESULTS: In this study, selenium enrichment significantly increased crude protein, soluble carbohydrate, total selenium, and organic selenium contents of alfalfa silage fresh and post-silage samples, and it significantly decreased neutral detergent fiber and acid detergent fiber contents (p < 0.05). Selenium enrichment altered the form of selenium in plants, mainly in the form of SeMet and SeMeCys, which were significantly higher than that of CK (p < 0.05). Selenium enrichment could significantly increase the lactic acid content, reduce the pH value, change the diversity of bacterial community, promote the growth of beneficial bacteria such as Lactiplantibacillus and inhibit the growth of harmful bacteria such as Pantoea, so as to improve the fermentation quality of silage. The in vitro digestibility of dry matter (IVDMD), in vitro digestibility of acid detergent fibers (IVADFD) and in vitro digestibility of acid detergent fibers (IVNDFD) of silage after selenium enrichment were significantly higher than those of CK (p < 0.05). CONCLUSION: This study showed that the presence of selenium could regulate the structure of the alfalfa silage bacterial community and improve alfalfa silage fermentation quality. Selenium enrichment measures can change the morphology of selenium in alfalfa silage products, thus promoting the conversion of organic selenium.

Electromagnetic-acoustic splitter with a tunable splitting ratio based on copper plates.

Acoustic splitters and electromagnetic splitters can be applied in various fields (e.g., navigation and interference detection). However, there is still a lack of study of structures that can simultaneously split acoustic and electromagnetic beams. In this study, a novel, to the best of our knowledge, electromagnetic-acoustic splitter (EAS) based on copper plates is proposed, which can simultaneously produce identical beam-splitting effects for transverse magnetic (TM)-polarized electromagnetic and acoustic waves. Different from previous beam splitters, the beam splitting ratio of the proposed passive EAS can be simply tuned by changing the incident angle of the input beam, i.e., a tunable splitting ratio can be achieved without additional energy consumption. The simulated results verify that the proposed EAS can create two transmitted split beams with a tunable splitting ratio for both electromagnetic and acoustic waves. This may have applications in dual-field navigation/detection, which can provide additional information and higher accuracy compared with single-field navigation/detection.

Full-space omnidirectional cloak by subwavelength metal channels filled with homogeneous dielectrics.

Cloaks can greatly reduce the scattering cross-section of hidden objects through various mechanisms, thereby making them invisible to outside observers. Among them, the full-space omnidirectional cloak based on transformation optic with full parameters are difficult to realize without metamaterials and often needs to be simplified before realization, while most cloaks with simplified parameters have limited working direction and cannot achieve omnidirectional cloaking effect. In this study, a full-space omnidirectional cloak is designed based on transformation optics and optic-null medium, which only needed natural materials without metamaterials. The designed omnidirectional cloak is realized by subwavelength metal channels filled with isotropic dielectrics whose refractive indices range from 1 to 2, which is homogeneous in each channel. The numerical simulation results verify good scattering suppression effect of the designed cloak for various detecting waves.

Emerging photodynamic/sonodynamic therapies for urological cancers: progress and challenges.

Photodynamic therapy (PDT), and sonodynamic therapy (SDT) that developed from PDT, have been studied for decades to treat solid tumors. Compared with other deep tumors, the accessibility of urological tumors (e.g., bladder tumor and prostate tumor) makes them more suitable for PDT/SDT that requires exogenous stimulation. Due to the introduction of nanobiotechnology, emerging photo/sonosensitizers modified with different functional components and improved physicochemical properties have many outstanding advantages in cancer treatment compared with traditional photo/sonosensitizers, such as alleviating hypoxia to improve quantum yield, passive/active tumor targeting to increase drug accumulation, and combination with other therapeutic modalities (e.g., chemotherapy, immunotherapy and targeted therapy) to achieve synergistic therapy. As WST11 (TOOKAD® soluble) is currently clinically approved for the treatment of prostate cancer, emerging photo/sonosensitizers have great potential for clinical translation, which requires multidisciplinary participation and extensive clinical trials. Herein, the latest research advances of newly developed photo/sonosensitizers for the treatment of urological cancers, and the efficacy, as well as potential biological effects, are highlighted. In addition, the clinical status of PDT/SDT for urological cancers is presented, and the optimization of the photo/sonosensitizer development procedure for clinical translation is discussed.

Increased BMSC exosomal miR-140-3p alleviates bone degradation and promotes bone restoration by targeting Plxnb1 in diabetic rats.

BACKGROUND: Diabetes mellitus (DM) is considered to be an important factor for bone degeneration disorders such as bone defect nonunion, which is characterized by physical disability and tremendous economy cost to families and society. Exosomal miRNAs of BMSCs have been reported to participate in osteoblastogenesis and modulating bone formation. However, their impacts on the development of bone degeneration in DM are not yet known. The role of miRNAs in BMSCs exosomes on regulating hyperglycemia bone degeneration was investigated in the present study. RESULTS: The osteogenic potential in bone defect repair of exosomes derived from diabetes mellitus BMSCs derived exosomes (DM-Exos) were revealed to be lower than that in normal BMSCs derived exosomes (N-Exos) in vitro and in vivo. Here, we demonstrate that miR-140-3p level was significantly altered in exosomes derived from BMSCs, ADSCs and serum from DM rats. In in vitro experiments, upregulated miR-140-3p exosomes promoted DM BMSCs differentiation into osteoblasts. The effects were exerted by miR-140-3p targeting plxnb1, plexin B1 is the receptor of semaphoring 4D(Sema4D) that inhibited osteocytes differentiation, thereby promoting bone formation. In DM rats with bone defect, miR-140-3p upregulated exosomes were transplanted into injured bone and accelerated bone regeneration. Besides, miR-140-3p in the exosomes was transferred into BMSCs and osteoblasts and promoted bone regeneration by targeting the plexin B1/RohA/ROCK signaling pathway. CONCLUSIONS: Normal-Exos and miR-140-3p overexpressed-Exos accelerated diabetic wound healing by promoting the osteoblastogenesis function of BMSCs through inhibition plexin B1 expression which is the receptor of Sema4D and the plexin B1/RhoA/ROCK pathway compared with diabetes mellitus-Exos. This offers a new insight and a new therapy for treating diabetic bone unhealing.

Simulation of an asymmetric hexagonal microcavity with high-ratio fluorescence and high-efficiency directional emission.

Ratiometric fluorescent sensors are widely used in biological sensing and immunoassays due to their high sensitivity detection of analytes. The high-ratio value of fluorescence can increase the sensitivity of the fluorescence sensor; in addition, the directional emission can improve the efficiency of light collection and improve the effective use of radiation power. In previous studies, low fluorescence ratios and low directional emission efficiency have restricted the application of ratio fluorescence sensors. Based on the above constraints, this paper proposes an asymmetric hexagonal microcavity structure. By destroying the complete rotational symmetry of the hexagon structure, it achieves high fluorescence ratios and high-efficiency directional emission in the far-field range in the near-infrared wavelength range, which is of significance for the development of high sensitivity fluorescence sensors.

Proteomic Analysis of Protective Effects of Epimedium Flavonoids against Ethanol-Induced Toxicity in Retinoic Acid-Treated SH-SY5Y Cells.

Alcohol (ethanol) is one of the most common addictive psychoactive substances in the world, and alcoholism may result in harmful effects on human health, especially on the nervous system. Flavonoids are regarded as the main active constituent in Epimedium, which has been used to cure some nervous system diseases such as amnesia for over 1000 years. Here, the protective effects of Epimedium flavonoids against ethanol-induced toxicity in retinoic acid (RA)-treated SH-SY5Y cells were investigated. Their mechanism was explored by a label-free proteomic approach combined with bioinformatic analysis for the first time. The results showed that ethanol treatment decreased cell viability by 18%, whereas the viability increased significantly after intervention with Epimedium flavonoids (p < 0.01). According to proteomic and bioinformatic analyses, hundreds of differentially expressed proteins (DEPs) were identified and classified as biological process (GO_BP), cellular component (GO_CC) and molecular function (GO_MF). Among them, GO_MF of DEPs, especially molecular function relevant to G proteins, greatly changed in SH-SY5Y cells pretreated by Epimedium flavonoids. In the alcoholism pathway, the expression of the Gi protein was up-regulated under the influence of ethanol, whereas Epimedium flavonoids could reverse the expression profile, both of which were validated by Western blot assay. In conclusion, Gi protein seemed to be an important factor in the alcoholism pathway to suppress the ethanol-induced toxicity of SH-SY5Y cells. These findings suggest a protective potential of Epimedium flavonoids against ethanol-induced toxicity to neurons via the regulation of Gi protein function.

Full-view imaging on dynamic closed surface by curved-to-flat conversion lens.

Conventional full-view imaging systems, which often need complicated image processing algorithms to reconstruct full-view images captured by motional/multiple cameras from different views, cannot have good real-time imaging capability. We design curved-to-flat conversion lens (CFCL) based on optic-null medium, which can directly project/image optical patterns from closed object surface onto image plane (e.g., the focal plane of microscopy), and shows good real-time full-view imaging performance. To realize the CFCL, the reduced optic-null medium is designed by subwavelength metal channels filled with homogeneous isotropic dielectrics. Numerical simulation results verify the function of the designed CFCL, which can image various dynamic optical patterns from the closed object surface to the finite-view image plane. The designed CFCL may have many applications in real-timely observing dynamic closed surfaces in full view, e.g., living tissue/cell and soft material's surface.

Surface transformation multi-physics for controlling electromagnetic and acoustic waves simultaneously.

A multi-physics null medium that performs as a perfect endoscope for both electromagnetic and acoustic waves is designed by transformation optics, which opens a new way to control electromagnetic and acoustic waves simultaneously. Surface transformation multi-physics, which is a novel graphical method to design multi-physics devices, is proposed based on the directional projecting feature of a multi-physics null medium. Many multi-physics devices, including beam shifters, scattering reduction, imaging devices and beam steering devices, for both electromagnetic and acoustic waves can be simply designed in a surface-corresponding manner. All devices designed by surface transformation multi-physics only need one homogeneous anisotropic medium (null medium) to realize, which can be approximately implemented by a brass plate array without any artificial sub-wavelength structures. Numerical simulations are given to verify the performances of the designed multi-physics devices made of brass plate array.

Designing conformal cloaks by manipulating structures directly in the physical space.

The method to elaborately design the refractive index profile in the lower Riemann sheet of Zhukovski transformation plays an important role in the performance of this kind of conformal cloaks. However, for most proposed schemes, the mathematical calculations are complex. Here, we propose a more convenient method to design conformal cloaks by manipulating structures directly in the physical space. The designed cloak only needs symmetrical metal boundaries filled with normal dielectrics (refractive index ranges from 1 to 2) in the 'circular branch cut', which would be more feasible for future experimental implementation. Numerical simulations are performed by using the finite element method to validate our theoretical analysis.

Magnifying lens designed by optical conformal mapping.

We proposed an alternative method to design a magnifying lens by optical conformal mapping. Different from previous hyperlens or superlens, the proposed lens needs no materials with negative or anisotropic refractive index. The lens has better photonic transporting efficiency than conventional a solid immersion lens due to impedance matching. The proposed lenses have many other advantages, such as broadband, low loss, and no need to redesign the sizes and material parameters when another magnifying ratio is required. Both numerical simulations and experimental demonstrations are implemented to verify the performance of the lens.

Asymmetric universal invisible gateway.

Previous invisible gateways are mainly based on super-scattering effect, which can only work for the perfect electric conductor (PEC) wall, while no further exploration is conducted for the walls made of other materials (i.e., the actual wall is not PEC). In this study, we design an asymmetric universal invisible gateway by transformation optics, which is versatile for applying arbitrary materials as wall materials. In addition, its unique asymmetric structure leads to the difference of the detection results when the relative position of the detection source and the invisible gateway changes: one side can only see a complete wall (no gateway) and the other side can detect the gateway in the middle of the wall. This research advances a new step for the specific application of invisible gateway.

Broadband Electromagnetic Wave Tunneling with Transmuted Material Singularity.

Subwavelength channels filled with near-zero-index (NZI) media can realize extraordinary optical functionalities, for example, tunneling electromagnetic wave without reflections, but usually confined in a narrow wavelength band due to the material singularity (refractive index n≈0), which seriously limits the practical potentials. In this Letter, we show this limit can be fundamentally overcome by an alternative, named near-zero-index-featured (NZIF) structure, with the singularity transmuted via a controlled optical conformal mapping, enabling the device implementation with nonmagnetic normal dielectrics (i.e., relative permittivity >1). Their equivalence is strictly examined through a subwavelength tunneling waveguide. Classic wave tunneling features in a broad frequency range are revealed in various confined geometries. These properties are robust against the disturbance of several kinds of structural defects benefited from the infinite effective local wavelength. The broadband and lossless NZIF medium proposed here provides a promising way to pursue the fascinating light controlling functionalities as initially enabled by singular NZI materials.

The Pseudomonas stutzeri-Specific Regulatory Noncoding RNA NfiS Targets katB mRNA Encoding a Catalase Essential for Optimal Oxidative Resistance and Nitrogenase Activity.

Pseudomonas stutzeri A1501 is a versatile nitrogen-fixing bacterium capable of living in diverse environments and coping with various oxidative stresses. NfiS, a regulatory noncoding RNA (ncRNA) involved in the control of nitrogen fixation in A1501, was previously shown to be required for optimal resistance to H2O2; however, the precise role of NfiS and the target genes involved in the oxidative stress response is entirely unknown. In this work, we systematically investigated the NfiS-based mechanisms underlying the response of this bacterium to H2O2 at the cellular and molecular levels. A mutant strain carrying a deletion of nfiS showed significant downregulation of oxidative stress response genes, especially katB, a catalase gene, and oxyR, an essential regulator for transcription of catalase genes. Secondary structure prediction revealed two binding sites in NfiS for katB mRNA. Complementation experiments using truncated nfiS genes showed that each of two sites is functional, but not sufficient, for NfiS-mediated regulation of oxidative stress resistance and nitrogenase activities. Microscale thermophoresis assays further indicated direct base pairing between katB mRNA and NfiS at both sites 1 and 2, thus enhancing the half-life of the transcript. We also demonstrated that katB expression is dependent on OxyR and that both OxyR and KatB are essential for optimal oxidative stress resistance and nitrogenase activities. H2O2 at low concentrations was detoxified by KatB, leaving O2 as a by-product to support nitrogen fixation under O2-insufficient conditions. Moreover, our data suggest that the direct interaction between NfiS and katB mRNA is a conserved and widespread mechanism among P. stutzeri strains.IMPORTANCE Protection against oxygen damage is crucial for survival of nitrogen-fixing bacteria due to the extreme oxygen sensitivity of nitrogenase. This work exemplifies how the small ncRNA NfiS coordinates oxidative stress response and nitrogen fixation via base pairing with katB mRNA and nifK mRNA. Hence, NfiS acts as a molecular link to coordinate the expression of genes involved in oxidative stress response and nitrogen fixation. Our study provides the first insight into the biological functions of NfiS in oxidative stress regulation and adds a new regulation level to the mechanisms that contribute to the oxygen protection of the MoFe nitrogenase.

NfiR, a New Regulatory Noncoding RNA (ncRNA), Is Required in Concert with the NfiS ncRNA for Optimal Expression of Nitrogenase Genes in Pseudomonas stutzeri A1501.

Expression of nitrogenase genes (nifHDK) is strictly regulated at both transcriptional and posttranscriptional levels. Efficient nitrogenase activity requires maintaining sufficient levels of nif mRNAs, yet the underlying mechanism is not fully understood due to its complexity. We have previously shown that a novel regulatory noncoding RNA (ncRNA), NfiS, optimizes nitrogen fixation through targeting nifK mRNA in Pseudomonas stutzeri A1501. Here, we report the identification and characterization of a second ncRNA inducible under nitrogen fixation conditions (nitrogen-free and microaerobic conditions), termed NfiR (for nitrogen fixation condition-inducible ncRNA), the expression of which is dependent on two global regulators, NtrC and Hfq. Comparative phenotypic and proteomic analyses of an nfiR mutant identify a role of NfiR in regulating the expression of nitrogenase genes. Further microscale thermophoresis and genetic complementation showed that an 11-nucleotide (nt) sequence in the stem-loop structure of NfiR (nucleotides 12 to 22) pairs with its counterpart in the coding region of nifD mRNA (nucleotides 1194 to 1207) by eight nucleotides. Significantly, deletion of nfiR caused a 60% reduction of nitrogenase activity, and the half-life of nifD mRNA was reduced from 20 min for the wild type to 15 min for the ΔnfiR mutant. With regard to nitrogenase activity and stability of the nifD and nifK transcripts, phenotypes were more severe for the double deletion mutant lacking nfiR and nfiS, suggesting that NfiR, in concert with NfiS, optimizes nitrogenase production at the posttranscriptional level.IMPORTANCE Biological nitrogen fixation is an energy-expensive process requiring the hydrolysis of 16 ATPs. Consequently, the expression of nif genes is highly regulated at both transcriptional and posttranscriptional levels through complex regulatory networks. Global regulation involves a number of regulatory proteins, such as the nif-specific activator NifA and the global nitrogen regulator NtrC, as well as various regulatory ncRNAs. We show that the two P. stutzeri ncRNAs, namely NfiS and NfiR (for nitrogen fixation condition-inducible ncRNA), optimize nitrogen fixation and environmental stress responses. NfiS and NfiR respond differently to various environmental signals and differ in their secondary structures. In addition, the two ncRNAs target the mRNAs of nifK and nifD, respectively. Such ncRNA-based posttranscriptional regulation of nitrogenase expression might be an evolved survival strategy, particularly in nitrogen-limiting environments. This study not only highlights the significant roles of regulatory ncRNAs in the coordination and fine tuning of various physiological processes but also provides a new paradigm for posttranscriptional regulation in nitrogen-fixing bacteria.

Thermal surface transformation and its applications to heat flux manipulations.

A new method to control heat flux, called thermal surface transformation (TST), is introduced from transformation thermodynamics. Compared with transformation thermodynamics, TST has many advantage. First, there is no mathematical calculation during the whole process in TST (novel thermal devices can be designed graphically in a surface-to-surface way). Second, all thermal devices of various functions, shapes and sizes designed by TST only require one homogenous anisotropic thermal medium, i.e., thermal-null medium (TNM). With the help of the effective medium theory, TNM can be realized by layered copper and expanded polystyrene, whose performance on controlling heat flux by TST is verified by numerical simulations. Many examples are given, including thermal imaging devices, thermal unidirectional cloak, concentrator, rotator and thermal focusing devices.

The Reason for Growth Inhibition of Ulmus pumila 'Jinye': Lower Resistance and Abnormal Development of Chloroplasts Slow Down the Accumulation of Energy.

Ulmus pumila 'Jinye', the colorful leaf mutant of Ulmus pumila L., is widely used in landscaping. In common with most leaf color mutants, U. pumila 'Jinye' exhibits growth inhibition. In this study, U. pumila L. and U. pumila 'Jinye' were used to elucidate the reasons for growth inhibition at the physiological, cellular microstructural, and transcriptional levels. The results showed that the pigment (chlorophyll a, chlorophyll b, and carotenoids) content of U. pumila L. was higher than that of U. pumila 'Jinye', whereas U. pumila 'Jinye' had a higher proportion of carotenoids, which may be the cause of the yellow leaves. Examination of the cell microstructure and RNA sequencing analysis showed that the leaf color and growth inhibition were mainly due to the following reasons: first, there were differences in the structure of the thylakoid grana layer. U. pumila L. has a normal chloroplast structure and clear thylakoid grana slice layer structure, with ordered and compact thylakoids. However, U. pumila 'Jinye' exhibited the grana lamella stacking failures and fewer thylakoid grana slice layers. As the pigment carrier and the key location for photosynthesis, the close stacking of thylakoid grana could combine more chlorophyll and promote efficient electron transfer promoting the photosynthesis reaction. In addition, U. pumila 'Jinye' had a lower capacity for light energy absorption, transformation, and transportation, carbon dioxide (CO2) fixation, lipopolysaccharide biosynthesis, auxin synthesis, and protein transport. The genes related to respiration and starch consumption were higher than those of U. pumila L., which indicated less energy accumulation caused the growth inhibition of U. pumila 'Jinye'. Finally, compared with U. pumila 'Jinye', the transcription of genes related to stress resistance all showed an upward trend in U. pumila L. That is to say, U. pumila L. had a greater ability to resist adversity, which could maintain the stability of the intracellular environment and maintain normal progress of physiological metabolism. However, U. pumila 'Jinye' was more susceptible to changes in the external environment, which affected normal physiological metabolism. This study provides evidence for the main cause of growth inhibition in U. pumila 'Jinye', information for future cultivation, and information on the mutation mechanism for the breeding of colored leaf trees.

Optical implementation of Riemann sheets: an analogy to an electromagnetic 'wormhole'.

Inspired by the branch cut that can link two Riemann sheets in complex function theory, we utilize the branch cut to mimic an electromagnetic 'wormhole' linking two 2D 'parallel spaces' in a reference space. With the help of optical conformal mapping, we design a time-varying inhomogeneous medium that can effectively perform like an electromagnetic 'wormhole' in the real space. Based on this method, we can simulate the evolutionary process of an electromagnetic 'wormhole' and the wave propagation from one space to another in a laboratory environment. The proposed device may also be applied in light capture, light modulators, and absorption with directional dependence.