Plants establish mutualistic associations with beneficial microbes while deploying the immune system to defend against pathogenic ones. Little is known about the interplay between mutualism and ...immunity and the mediator molecules enabling such crosstalk. Here, we show that plants respond differentially to a volatile bacterial compound through integral modulation of the immune system and the phosphate‐starvation response (PSR) system, resulting in either mutualism or immunity. We found that exposure of Arabidopsis thaliana to a known plant growth‐promoting rhizobacterium can unexpectedly have either beneficial or deleterious effects to plants. The beneficial‐to‐deleterious transition is dependent on availability of phosphate to the plants and is mediated by diacetyl, a bacterial volatile compound. Under phosphate‐sufficient conditions, diacetyl partially suppresses plant production of reactive oxygen species (ROS) and enhances symbiont colonization without compromising disease resistance. Under phosphate‐deficient conditions, diacetyl enhances phytohormone‐mediated immunity and consequently causes plant hyper‐sensitivity to phosphate deficiency. Therefore, diacetyl affects the type of relation between plant hosts and certain rhizobacteria in a way that depends on the plant's phosphate‐starvation response system and phytohormone‐mediated immunity.
Synopsis
A volatile compound produced by a plant growth‐promoting rhizobacterium differentially affects phytohormone‐mediated immunity in phosphate‐sufficient and ‐deficient plants, thus modulating their response to symbiont colonization.
Exposure to a plant growth‐promoting rhizobacterium Bacillus amyloliquefaciens can cause either beneficial or deleterious effects on Arabidopsis thaliana plants depending on their nutrition status.
The beneficial vs. deleterious effects of the rhizobacterium depend on the availability of phosphate (Pi) to the plant.
The effect of the rhizobacterium on plant fitness is mediated by the volatile bacterial metabolite diacetyl (DA).
In Pi‐sufficient plants, DA partially suppresses plant immune response and enhances symbiont colonization without compromising disease resistance.
In Pi‐deficient plants, DA enhances phytohormone‐mediated immune response and causes plant hypersensitivity to Pi deficiency.
A volatile compound produced by a plant growth‐promoting rhizobacterium differentially affects plant immunity and plant response to symbiont colonization depending on phosphate availability.
Purpose
The rest-to-rest movements for a spacecraft, such as attitude adjustment and orbital manoeuver, are likely to excite residual vibration of flexible appendages, which may affect the attitude ...accuracy and even result in severe structural damage. The purpose of this paper is to present an approach to attenuating the vibration of flexible solar array by using reaction flywheel.
Design/methodology/approach
The reaction flywheel installed on solar array served as an actuator to provide reaction torque to a structure according to a designed feedback control law. This torque can be considered as an artificial damping. Experiment on a scale model of the solar array is first performed to verify the effectiveness of this method. Numerical simulation on finite element model of a full-scale solar array is subsequently carried out to confirm the validity of this method for practical engineering application.
Findings
The vibration suppression effect on the structure using a reaction flywheel is deduced by theoretical analysis. Results from both experiment and numerical simulation reveal that the efficiency of vibration attenuation is promoted.
Research limitations/implications
Improvements on control law are left for further study. Additionally, only the first-order bending vibration of the flexible solar array is attenuated, and further study is required for other types of vibration suppression.
Practical implications
An effective method is proposed for spacecraft designers to actively suppress the vibration of the flexible solar array.
Originality/value
A novel active vibration reduction scheme is proposed using a reaction flywheel to suppress vibration of the flexible solar array. This paper fulfils a source of theoretical analysis and experimental studies for vibration reduction measure design and provides practical help for the spacecraft designers.
Hepatocellular carcinoma (HCC) is the leading cause of cancer mortality. Chemical and virus induction are two major risk factors, however, the potential molecular mechanisms of their differences ...remain elusive. In this study, to identify the similarities and differences between chemical and virus induced HCC models, we compared the gene expression profiles between DEN and HBx mice models, as well as the differences among tumor, para-tumor and normal tissues.
We sequenced both gene and microRNA (miRNA) expression for HCC tumor tissues, para-tumor and normal liver tissues from DEN model mice (30-week-old) and downloaded the corresponding microarray expression data of HBx model from GEO database. Then differentially expressed genes (DEGs), miRNAs and transcription factors (TFs) were detected by R packages and performed functional enrichment analysis. To explore the gene regulatory network in HCC models, miRNA and TF regulatory networks were constructed by target prediction.
For model comparison, although DEGs between tumor and normal tissues in DEN and HBx models only had a small part of overlapping, they shared common pathways including lipid metabolism, oxidation-reduction process and immune process. For tissue comparisons in each model, genes in oxidation-reduction process were down-regulated in tumor tissues and genes in inflammatory response showed the highest expression level in para-tumor tissues. Genes highly expressed in both tumor and para-tumor tissues in two models mainly participated in immune and inflammatory response. Genes expressed in HBx model were also involved in cell proliferation and cell migration etc. Network analysis revealed that several miRNAs such as miR-381-3p, miR-142a-3p, miR-214-3p and TFs such as Egr1, Atf3 and Klf4 were the core regulators in HCC.
Through the comparative analyses, we found that para-tumor tissue is a highly inflammatory tissue while the tumor tissue is specific with both inflammatory and cancer signaling pathways. The DEN and HBx mice models have different gene expression pattern but shared pathways. This work will help to elucidate the molecular mechanisms underlying different HCC models.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Cross-kingdom herbal miRNA was first reported in 2012. Using a modified herbal extraction protocol, we obtained 73,677,287 sequences by RNA-seq from 245 traditional Chinese Medicine (TCM), of which ...20,758,257 were unique sequences. We constructed a Bencao (herbal) small RNA (sRNA) Atlas ( http://bencao.bmicc.cn ), annotated the sequences by sequence-based clustering, and created a nomenclature system for Bencao sRNAs. The profiles of 21,757 miRNAs in the Atlas were highly consistent with those of plant miRNAs in miRBase. Using software tools, our results demonstrated that all human genes might be regulated by sRNAs from the Bencao sRNA Atlas, part of the predicted human target genes were experimentally validated, suggesting that Bencao sRNAs might be one of the main bioactive components of herbal medicines. We established roadmaps for oligonucleotide drugs development and optimization of TCM prescriptions. Moreover, the decoctosome, a lipo-nano particle consisting of 0.5%-2.5% of the decoction, demonstrated potent medical effects. We propose a Bencao (herbal) Index, including small-molecule compounds (SM), protein peptides (P), nucleic acid (N), non-nucleic and non-proteinogenic large-molecule compounds (LM) and elements from Mendeleev's periodic table (E), to quantitatively measure the medical effects of botanic medicine. The Bencao sRNA Atlas is a resource for developing gene-targeting oligonucleotide drugs and optimizing botanical medicine, and may provide potential remedies for the theory and practice of one medicine.
Wear leads to performance degradation of the wire rope and seriously threatens its service reliability. This paper explored the tribological behavior of a transmission wire rope by a homemade ...rope-sheave sliding friction and wear test rig. Then, the strength and fatigue performance of the wire rope with different surface wear were investigated using customized test apparatuses. The results show that the friction coefficient (COF) is affected by the rope structure, contact angle and sliding velocity, which decreases from approximately 0.65 to 0.32 with increasing sliding velocity. The friction temperature rise is obviously influenced by the sliding velocity. It increases nonlinearly from approximately 51 °C to approximately 102 °C. The wear characteristics are mainly spalling, furrows and plastic deformation. The wear mechanisms are adhesive wear and abrasive wear. Additionally, with a decrease in sliding velocity, the breaking force decreases from approximately 48.7 kN–41.2 kN, and the bending fatigue life reduces nonlinearly. The maximum bending fatigue times decrease from approximately 9.9 k to 3.2 k. Furthermore, the surface wear accelerates the crack propagation rate of the service wire rope. The fracture mechanism of the wire rope is mainly ductile fracture under tensile loading and brittle fracture under fatigue loading.
Display omitted
•The COF of wire rope is affected by contact angle and sliding velocity.•Surface wear degree decreases with the increase of sliding parameters.•Wear characteristics are mainly spalling, furrow and plastic deformation.•Mechanical properties degenerate nonlinearly with the sliding velocity decreases.•Wear accelerates the crack propagation and reduces the fatigue life of the wire rope.
Recent population studies have significantly advanced our understanding of how age shapes the gut microbiota. However, the actual role of age could be inevitably confounded due to the complex and ...variable environmental factors in human populations. A well-controlled environment is thus necessary to reduce undesirable confounding effects, and recapitulate age-dependent changes in the gut microbiota of healthy primates. Herein we performed 16S rRNA gene sequencing, characterized the age-associated gut microbial profiles from infant to elderly crab-eating macaques reared in captivity, and systemically revealed the lifelong dynamic changes of the primate gut microbiota. While the most significant age-associated taxa were mainly found as commensals such as Faecalibacterium, the abundance of a group of suspicious pathogens such as Helicobacter was exclusively increased in infants, underlining their potential role in host development. Importantly, topology analysis indicated that the network connectivity of gut microbiota was even more age-dependent than taxonomic diversity, and its tremendous decline with age could probably be linked to healthy aging. Moreover, we identified key driver microbes responsible for such age-dependent network changes, which were further linked to altered metabolic functions of lipids, carbohydrates, and amino acids, as well as phenotypes in the microbial community. The current study thus demonstrates the lifelong age-dependent changes and their driver microbes in the primate gut microbiota, and provides new insights into their roles in the development and healthy aging of their hosts.
Depression filling is a critical step in distributed hydrological modeling using digital elevation models (DEMs). The traditional Priority‐Flood (PF) approach is widely used due to its relatively ...high efficiency when dealing with a small‐sized DEM. However, it seems inadequate and inefficient when dealing with large high‐resolution DEMs. In this work, we examined the relationship between the PF algorithm calculation process and the topographical characteristics of depressions, and found significant redundant calculations in the local micro‐relief areas in the conventional PF algorithm. As such calculations require more time when dealing with large DEMs, we thus propose a new variant of the PF algorithm, wherein redundant points and calculations are recognized and eliminated based on the local micro‐relief water‐flow characteristics of the depression‐filling process. In addition, depressions and flatlands were optimally processed by a quick queue to improve the efficiency of the process. The proposed method was applied and validated in eight case areas using the Shuttle Radar Topography Mission digital elevation model (SRTM‐DEM) with 1 arc‐second resolution. These selected areas have different data sizes. A comparative analysis among the proposed method, the Wang and Liu‐based PF, the improved Barnes‐based PF, the improved Zhou‐based PF, and the Planchon and Darboux (P&D) algorithms was conducted to evaluate the accuracy and efficiency of the proposed algorithm. The results showed that the proposed algorithm is 43.2% (maximum) faster than Wang and Liu's variant of the PF method, with an average of 31.8%. In addition, the proposed algorithm achieved similar performance to the improved Zhou‐based PF algorithm, though our algorithm has the advantage of being simpler. The optimal strategies using the proposed algorithm can be employed in various landforms with high efficiency. The proposed method can also achieve good depression filling, even with large amounts of DEM data.
Emerging evidence has been reported to support the involvement of the gut microbiota in the host's blood lipid and hyperlipidemia (HLP). However, there remains unexplained variation in the host's ...blood lipid phenotype. Herein a nonhuman primate HLP model was established in cynomolgus monkeys fed a high-fat diet (HFD) for 19 months. At month 19%, 60% (3/5) of the HFD monkeys developed HLP, but surprisingly 40% of them (2/5) exhibited strong tolerance to the HFD (HFD-T) with their blood lipid profiles returning to normal levels. Metagenomic analysis was used to investigate the compositional changes in the gut microbiota in these monkeys. Furthermore, the relative abundance of
remarkably increased and became the dominant gut microbe in HFD-T monkeys. A validation experiment showed that transplantation of fecal microbiota from HFD-T monkeys reduced the blood lipid levels and hepatic steatosis in HLP rats. Furthermore, the relative abundance of
significantly increased in rats receiving transplantation, confirming the successful colonization of the microbe in the host and its correlation with the change of the host's blood lipid profiles. Our results thus suggested a potentially pivotal lipid-lowering role of
in the gut microbiota, which could contribute to the variation in the host's blood lipid phenotype.
Parkinson’s disease (PD) is a complex neurological disorder characterized by motor and nonmotor features. Although some drugs have been developed for the therapy of PD in a clinical setting, they ...only alleviate the clinical symptoms and have yet to show a cure. In this study, by employing the C. elegans model of PD, we found that ferulic acid (FA) significantly inhibited α-synuclein accumulation and improved dyskinesia in NL5901 worms. Meanwhile, FA remarkably decreased the degeneration of dopaminergic (DA) neurons, improved the food-sensing behavior, and reduced the level of reactive oxygen species (ROS) in 6-OHDA-induced BZ555 worms. The mechanistic study discovered that FA could activate autophagy in C. elegans, while the knockdown of 3 key autophagy-related genes significantly revoked the neuroprotective effects of FA in α-synuclein- and 6-OHDA-induced C. elegans models of PD, demonstrating that FA exerts an anti-PD effect via autophagy induction in C. elegans. Furthermore, we found that FA could reduce 6-OHDA- or H2O2-induced cell death and apoptosis in PC-12 cells. Moreover, FA was able to induce autophagy in stable GFP-RFP-LC3 U87 cells and PC-12 cells, while bafilomycin A1 (Baf, an autophagy inhibitor) partly eliminated the protective effects of FA against 6-OHDA- and H2O2-induced cell death and ROS production in PC-12 cells, further confirming that FA exerts an anti-PD effect via autophagy induction in vitro. Collectively, our study provides novel insights for FA as a potent autophagy enhancer to effectively prevent neurodegenerative diseases such as PD in the future.
The automatic recognition of landforms is regarded as one of the most important procedures to classify landforms and deepen the understanding on the morphology of the earth. However, landform types ...are rather complex and gradual changes often occur in these landforms, thus increasing the difficulty in automatically recognizing and classifying landforms. In this study, small-scale watersheds, which are regarded as natural geomorphological elements, were extracted and selected as basic analysis and recognition units based on the data of SRTM DEM. In addition, datasets integrated with terrain derivatives（e.g., average slope gradient, and elevation range） and texture derivatives（e.g., slope gradient contrast and elevation variance） were constructed to quantify the topographical characteristics of watersheds. Finally, Random Forest（RF） method was employed to automatically select features and classify landforms based on their topographical characteristics. The proposed method was applied and validated in seven case areas in the Northern Shaanxi Loess Plateau for its complex andgradual changed landforms. Experimental results show that the highest recognition accuracy based on the selected derivations is 92.06%. During the recognition procedure, the contributions of terrain derivations were higher than that of texture derivations within selected derivative datasets. Loess terrace and loess mid-mountain obtained the highest accuracy among the seven typical loess landforms. However, the recognition precision of loess hill, loess hill–ridge, and loess sloping ridge is relatively low. The experiment also shows that watershed-based strategy could achieve better results than object-based strategy, and the method of RF could effectively extract and recognize the feature of landforms.
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