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Over the past decades, unmanned aerial vehicles (UAVs) have been widely used in both military and civilian fields. In these applications, flocking motion is a fundamental but crucial operation of multi-UAV systems. Traditional flocking motion methods usually designed for a specific environment. However, the real environment is mostly unknown and stochastic, which greatly reduces the practicality of these methods. In this paper, deep reinforcement learning (DRL) is used to realize the flocking motion of multi-UAV systems. Considering that the sim-to-real problem restricts the application of DRL to the flocking motion scenario, a digital twin (DT) enabled DRL training framework is proposed to solve this problem. The DRL model can learn from DT and be quickly deployed on the real-world UAV with the help of DT. Under this training framework, this paper proposes an actor-critic DRL algorithm named behavior-coupling deep deterministic policy gradient (BCDDPG) for the flocking motion problem, which is inspired by the flocking behavior of animals. Extensive simulations are conducted to evaluate the performance of BCDDPG. Simulation results show that BCDDPG achieves a higher average reward and performs better in terms of arrival rate and collision rate compared with existing methods.

CRISPR-associated Rossmann fold (CARF) domain signaling underpins modulation of CRISPR-Cas nucleases; however, the RtcR CARF domain controls expression of two conserved RNA repair enzymes, cyclase RtcA and ligase RtcB. Here, we demonstrate that RtcAB are required for RtcR-dependent transcription activation and directly bind to RtcR CARF. RtcAB catalytic activity is not required for complex formation with CARF, but is essential yet not sufficient for RtcRAB-dependent transcription activation, implying the need for an additional RNA repair-dependent activating signal. This signal differs from oligoadenylates, a known ligand of CARF domains, and instead appears to originate from the translation apparatus: RtcB repairs a tmRNA that rescues stalled ribosomes and increases translation elongation speed. Taken together, our data provide evidence for an expanded range for CARF domain signaling, including the first evidence of its control via in trans protein-protein interactions, and a feed-forward mechanism to regulate RNA repair required for a functioning translation apparatus.

Natural soil has the ability to suppress the soil-borne pathogen to a certain extent, and the assemblage of soil microbiome plays a crucial role in maintaining such ability. Long-term monoculture accelerates the forms of soil microbiome and leads to either disease conducive or suppressive soils. Here, we explored the impact of soil conditions on bacterial wilt disease (healthy or diseased) under long-term tobacco monoculture on the assemblage of bacterial and fungal communities in bulk and rhizosphere soils during the growth periods. With Illumina sequencing, we compared the bacterial and fungal composition of soil samples from tobacco bacterial wilt diseased fields and healthy fields in three growth periods. We found thatProteobacteriaandAscomycotawere the most abundant phylum for bacteria and fungi, respectively. Factors of soil conditions and tobacco growth periods can significantly influence the microbial composition in bulk soil samples, while the factor of soil conditions mainly determined the microbial composition in rhizosphere soil samples. Next, rhizosphere samples were further analyzed with LEfSe to determine the discriminative taxa affected by the factor of soil conditions. For bacteria, the genusRalstoniawas found in the diseased soils, whereas the genusFlavobacteriumwas the only shared taxon in healthy soils; for fungi, the genusChaetomiumwas the most significant taxon in healthy soils. Besides, network analysis confirmed that the topologies of networks of healthy soils were higher than that of diseased soils. Together, our results suggest that microbial assemblage in the rhizosphere will be largely affected by soil conditions especially after long-term monoculture.

Growth promotion and stress tolerance induced by endophytes have been observed in various plants, but their effects on mulberry regularly suffering flood in the hydro-fluctuation belt are less understood. In the present study, endophytic

Plant growth-promoting rhizobacteria have been shown to play important roles in maintaining host fitness under periods of abiotic stress, and yet their effect on mulberry trees which regularly suffer drought after flooding in the hydro-fluctuation belt of the Three Gorges Reservoir Region in China remains largely uncharacterized. In the present study, 74 bacterial isolates were obtained from the rhizosphere soil of mulberry after drought stress, including 12 phosphate-solubilizing and 10 indole-3-acetic-acid-producing isolates. Bacillus megaterium HGS7 was selected for further study due to the abundance of traits that might benefit plants. Genomic analysis revealed that strain HGS7 possessed multiple genes that contributed to plant growth promotion, stress tolerance enhancement, and antimicrobial compound production. B. megaterium HGS7 consistently exhibited antagonistic activity against phytopathogens and strong tolerance to abiotic stress in vitro. Moreover, this strain stimulated mulberry seed germination and seedling growth. It may also induce the production of proline and antioxidant enzymes in mulberry trees to enhance drought tolerance and accelerate growth recovery after drought stress. The knowledge of the interactions between rhizobacteria HGS7 and its host plant might provide a potential strategy to enhance the drought tolerance of mulberry trees in a hydro-fluctuation belt.

Bacterial wilt, caused by the plant pathogen Ralstonia solanacearum, occurs more severely in acidified soil according to previous reports. However, R. solanacearum cannot grow well in acidic environments under barren nutrient culture conditions, especially when the pH is lower than 5. With the worsening acidification of farmland, further determination of how R. solanacearum adapts to the long-term acidic environment is worthwhile. In this study, experimental evolution was applied to evaluate the adaptability and mechanism of the R. solanacearum experimental population responding to long-term acid stress. We chose the CQPS-1 strain as the ancestor, and minimal medium (MM medium) with different pH values as the culture environment to simulate poor soil. After 1500 generations of serial passage experiments in pH 4.9 MM, acid-adapted experimental strains (denoted as C49 strains) were obtained, showing significantly higher growth rates than the growth rates of control experimental strains (serial passage experiment in pH 6.5 MM, denoted as C65 strains). Competition experiments showed that the competitive indices (CIs) of all selected clones from C49 strains were superior to the ancestor in acidic environment competitiveness. Based on the genome variation analysis and functional verification, we confirmed that loss of function in the phcA gene was associated with the acid fitness gain of R. solanacearum, which meant that the inactivation of the PhcA regulator caused by gene mutation mediated the population expansion of R. solanacearum when growing in an acidic stress environment. Moreover, the swimming motility of acid evolution strains and the phcA deletion mutant was significantly enhanced compared to CQPS-1. This work provided evidence for understanding the adaptive strategy of R. solanacearum to the long-term acidic environment.

In recent years, the low sensitivity caused by plasma quenching has restricted the development of LIBS technology in practical applications. In order to improve the sensitivity of the LIBS analysis method, we proposed a nanoparticle-assisted metal–organic framework (MOF) enhanced laser-induced breakdown spectroscopy, which combines a metal–organic framework (MOF), Au nanoparticles (AuNPs), and a portable LIBS instrument. Common metal ions in water were selected as the research objects to be tested by the proposed method. First, the synthesized three-dimensional (3D) MOF, namely [Zn2(L2)]2DMA·3H2O (complex 1) [H2L = 2-(imidazole-1-yl)terephthalic acid], was used to capture metal ions. Second, complex 1 loaded with metal ions induced AuNPs to aggregate on its surface. Third, the samples were attached to the glass substrate with double-sided tape and analyzed by LIBS. As a result, the limits of detection (LODs) for Pb and Cr obtained in this work were 8.0 and 4.2 ng mL−1, respectively, which were notably 8–10 times lower than those of the complex 1 enrichment method alone and 4 orders of magnitude lower than those of traditional LIBS methods. The significant improvement in LODs was also a new breakthrough for LIBS in liquid analysis. The great improvement in sensitivity can be mainly attributed to the unique microporous structure and the exposed metal binding sites of complex 1, which provide a huge space to accommodate metal ions. Also, the coupling action between laser electromagnetic fields and the surface plasmon of AuNPs greatly improved the laser ablation efficiency in the process of laser–matter interaction. Finally, the analysis of actual samples yielded good recoveries (92.8–99.0%) and reproducibility (lower than 11.9%), which shows the great potential of the combination of this method and portable LIBS in-field detection.

This study has identified two polymer additives that when added in low concentrations can be used to reliably prevent incongruent melting of sodium acetate trihydrate (SAT) when temperature-cycled over multiple thousands of melting and freezing cycles. The polymers appear to act as crystal-habit modifiers that at sub-optimal concentrations dramatically alter the morphology of any anhydrous sodium acetate that may be formed, and at higher concentrations completely suppress precipitation of anhydrous sodium acetate. In situ X-ray powder diffraction experiments show that the active nucleator for SAT is Na2HPO4·2H2O, and that the mechanism of thermally induced deactivation is dehydration in solution to form anhydrous Na2HPO4. Based on these studies, new formulations of SAT have been developed that demonstrate consistent and reliable performance as phase-change materials for heat-storage applications.

The cause of some patients with negative RT-PCR results experienced turn-positive after treatment remains unclear. In addition, understanding the correlation between changes in clinical data in the course of COVID-19 and treatment outcomes is of great importance in determining the prognosis of COVID-19. To perform cause analysis of RT-PCR turn-positive and the effective screening factors related to treatment outcome in COVID-19. Clinical data, including clinical manifestations, laboratory tests, radiography results, treatment methods and outcomes, were retrospectively collected and analyzed from January to March 2020 in Renmin Hospitals of Wuhan University. 116 COVID-19 patients (40 in recurrent group, 29 in recovered group and 47 in unrecovered group) were recruited. In the recurrent group, white blood cell, Neutrophils, prothrombin time, activated partial thromboplastin time, CD3, CD4, CD8, ratio of CD4/CD8, IgG and C4 complement were of significant difference among the baseline, negative and turn-positive time points. CD19 and CT scan results were found notable difference between recurrent group and recovered group. Odds from CD3, CD4, CD8, CD19, IgM, C3 complement, C4 complement and CT scan results validated associations with clinical outcomes of COVID-19. The so-called recurrence in some COVID-19 patients may be due to the false-negative of nucleic acid test results from nasopharyngeal swabs. Levels of CD3, CD4, CD8, CD19, IgM, C3 complement, C4 complement and CT results were significantly correlated with the outcome of COVID-19. The cellular immunity test could be beneficial to further screen the reliability of RT-PCR test on the basis of CT images.

Background Cervical cancer (CC) is the one of most common malignant gynecological tumors, which is characterized with the high mortality and recurrence rate. Previous studies have elucidated the oncogenic role of small nucleolar RNA host gene 6 (SNHG6) in some types of human cancers, whereas it is unclear whether it functions as an oncogene in CC. This study was aimed at unveiling the role of SNHG6 in CC. Methods qRT-PCR analysis was implemented to evaluate the expression levels of SNHG6, miR-485-3p and STYX in CC cells. RNA pull down assay and luciferase reporter assay were conducted to verify the interaction between miR-485-3p and SNHG6 or STYX. Functional assays, such as colony formation assay, JC-1 assay and TUNEL assay were applied to detect the biological behaviors of CC cells. The resistance of CC cells to radiation was evaluated by colony formation assay. Results SNHG6 was expressed at a high level in CC cells. Silenced SNHG6 suppressed cell proliferation but promoted cell apoptosis. Additionally, silenced SNHG6 could sensitize CC cells to radiation treatment. miR-485-3p could bind to both SNHG6 and STYX. Knockdown of miR-485-3p or overexpression of STYX could abolish the effects of SNHG6 silencing on CC cell growth. Conclusions LncRNA SNHG6 enhances the radioresistance of CC cells and promotes CC cell growth by sponging miR-485-3p to release STYX.

Background Mycotoxins have received much attention due to their potential harmful impact on humans. Increasing awareness of environmental protection and food safety prompts the use of eco-friendly and biosafe strategies for mycotoxin elimination in food production. Scope and approach Mycotoxin adsorption by microorganisms has become increasingly promising due to its environmental friendliness and efficiency. This review is mainly focused on discussing different kinds of microorganisms able to adsorb mycotoxins, exploring the main mechanisms of yeast and lactic acid bacterial bioadsorption actions involving cell wall physical structure, chemical components, and their complicated interactions with mycotoxins. Moreover, industrial applications and future research needs are also proposed. Key findings and conclusions Yeasts and lactic acid bacteria have the great advantages of their adsorption capability and being food security friendly, and their complicated interactions with mycotoxins indicate that cell wall structural integrity, physical structure and morphology, and chemical components all play important roles in the adsorption process. On this basis, future approaches may rely on combinations of different microorganism to provide complementary advantages in mycotoxin degradation and adsorption.

Bacterial wilt is accompanied by microbial communities shift and soil acidification. However, the relationship between the changes of bacterial communities and bacterial wilt under the influence of different acidification levels has not been fully elucidated. Here, we analyzed the abundance of Ralstonia solanacearum, rhizosphere bacterial communities and carbon metabolism at differently acidic levels (pH 6.45, pH 5.60, pH 5.35, pH 4.90 and pH 4.45) and soil amendment treatment (CaO). The results indicated that both the abundance of R. solanacearum and the incidence of bacterial wilt showed a significant trend of first increasing and then decreasing with the increase of soil pH. The Firmicutes phylum and potentially beneficial genera

Plant growth-promoting rhizobacteria have been shown to play important roles in maintaining host fitness under periods of abiotic stress, and yet their effect on mulberry trees which regularly suffer drought after flooding in the hydro-fluctuation belt of the Three Gorges Reservoir Region in China remains largely uncharacterized. In the present study, 74 bacterial isolates were obtained from the rhizosphere soil of mulberry after drought stress, including 12 phosphate-solubilizing and 10 indole-3-acetic-acid-producing isolates.

Drought stress often leads to heavy losses in mulberry planting, especially for fruits and leaves. Application of plant growth-promoting fungi (PGPF) endows various plant beneficial traits to overcome adverse environmental conditions, but little is known about the effects on mulberry under drought stress. In the present study, we isolated 64 fungi from well-growing mulberry trees surviving periodical drought stress, and Talaromyces sp. GS1, Pseudeurotium sp. GRs12, Penicillium sp. GR19, and Trichoderma sp. GR21 were screened out due to their strong potential in plant growth promotion. Co-cultivation assay revealed that PGPF stimulated mulberry growth, exhibiting increased biomass and length of stems and roots. Exogenous application of PGPF could alter fungal community structures in the rhizosphere soils, wherein Talaromyces was obviously enhanced after inoculation of Talaromyces sp. GS1, and Peziza was increased in the other treatments. Moreover, PGPF could promote iron and phosphorus absorption of mulberry as well. Additionally, the mixed suspensions of PGPF induced the production of catalase, soluble sugar, and chlorophyll, which in turn enhanced the drought tolerance of mulberry and accelerated their growth recovery after drought. Collectively, these findings might provide new insights into improving mulberry drought tolerance and further boosting mulberry fruit yields by exploiting interactions between hosts and PGPF.

The effects of global warming have warmed the climate of the Qinghai-Tibetan Plateau (QTP) leading to changes in plant growth and soil nutrients in the alpine meadows. However, few studies have addressed the effects of warming on plant allometric growth and soil stoichiometry in these meadows on a long-term scale. Therefore, the effects of soil stoichiometry on plant allometric growth remain unclear under long-term warming in the alpine meadows. This study adopted infrared radiators to conduct an 8-year warming experiment in a permafrost region on the QTP starting in 2010, and surveyed growth indices of the plant community during the growing season. Soil organic carbon (C), total nitrogen (N), and total phosphorus (P) in an alpine meadow were measured. We initially learned that the aboveground part of the alpine meadow vegetation in the warming treatment changed from an isometric to an allometric growth pattern while the allometric growth pattern of the belowground part was further strengthened. Second, the contents of soil C, N, and P decreased at the 0–20 cm depth and increased at the 20–30 cm depth in warming. The ratios of soil C:N, C:P, and N:P showed increasing trends at different soil depths with artificial warming, and their amplitudes increased with soil depths. Warming promoted the migration of soil stoichiometric characteristics of C, N, and P to deep soil. Finally, the correlations of plant growth with soil stoichiometric characteristics were weakened by warming, demonstrating that the downward migration of soil stoichiometric characteristics to deep soil in warming had effects on the growth of vegetation in the alpine meadow. It concludes that the change in soil stoichiometric characteristics with soil depths promotes plant allometric growth in the alpine meadow under climate warming.

The basic position of microscope in experimental teaching is increasingly prominent, but there is still a big gap between its multidimensional index factors such as operation efficiency, effectiveness, and user satisfaction and the goal of teaching application. Based on the usability design theory, Kinovea video analysis software and ANSYS finite element analysis software were separately used to carry out user observation and product structure testing and analyze the multiple heterogeneous factors affecting the use of microscopes in teaching application scenarios and record usability data; the Fuzzy Analytic Hierarchy Process was utilized to summarize and analyze the usability data and construct a usability evaluation model of microscope. Under the guidance of the usability evaluation model, the microscope was optimized, and its usability was verified by Jack simulation and finite element analysis at last. The results show that: On the layer of operational efficiency, the usability index of intuitive operation and easy to learn of the microscope accounts for the largest weight. On the layer of effectiveness, the index of stable structural connection of the microscope has a larger weight; adjusting the material properties and product structure can effectively improve the stability of the microscope. On the layer of user satisfaction, the index of use comfortably of the microscope accounts for the largest weight, and the comfort of students’ neck and other joints can be improved by optimizing the microscope’s functional layout. This research provides an evaluation index reference and design optimization experience for the multiple heterogeneous factor-driven microscope usability design in teaching applications.

Objective. In order to explore whether the application of statins can improve the prognosis of patients with intracerebral hemorrhage. Methods. Studies of patients with intracerebral hemorrhage taking statins published in English until December 2021 were searched based on limited search terms, the retrieved literature was screened out based on inclusion and exclusion criteria, and the quality assessment and data extraction were carried out independently by two investigators. The extracted clinical data were then meta-analyzed. Results. A total of 17 literatures were included in this study, with a sample size of 16,988 cases, including 3,001 cases in the statin group and 13,487 cases in the control group. MRS score of mortality was used as the prognostic index to evaluate cerebral hemorrhage. According to the Newcastle-Ottawa Scale (NOS), the score of literature quality evaluation scale was 6–8, indicating good literature quality. Meta-analysis of clinical data extracted from the literature showed that the statin group reduced overall mortality after intracerebral hemorrhage compared with the nonstatin group ( P < 0.01 ). In terms of improving functional prognosis, the statin group improved functional prognosis 90 days after intracerebral hemorrhage ( P = 0.01 ). There was no significant difference between the statin and nonstatin groups in reducing the number of intracerebral hematomas. Conclusions. Statins can reduce the total mortality after ICH and improve the survival rate (90 d), without increasing the amount of hematoma.

Bacterial wilt, caused by the plant pathogen

Rapid detection and efficient removal of heavy metal ions from environmental water are of considerable importance to tackle the water pollution problem. In this work, a simple but efficient strategy named metal-chelate induced nanoparticle aggregation enhanced laser-induced breakdown spectroscopy (MINAELIBS) was proposed for signal enhancement aiming at ultra-sensitive detection of trace levels of metal elements in liquid samples. Unlike the surface contact approach previously reported in the literature, direct mixing of gold nanoparticles (AuNPs) and metal chelates increased the contact area, adhesion force, and uniformity between analytes and AuNPs. As a result, under the optimal conditions, the limits of detection (LODs) of Cd, Cu, Ag, Pb, and Cr were 4.6, 1.5, 3.4, 3.5, and 3.5 ng mL−1, respectively. The LODs of target elements were notably 7–10 times lower than those of chelating reagent enrichment alone and 3–4 orders of magnitude lower compared to traditional LIBS methods, which demonstrates the feasibility of MINAELIBS in analysis of liquid samples at the ppb level. Application of AuNPs for high-performance signal enhancement has undoubtedly pushed the method sensitivity of traditional LIBS analyses to a new level. In addition, the recoveries of all the analytical elements in the environmental water samples were in the range from 88.6% to 109.9%, which further proves the feasibility and potential of MINAELIBS in practical liquid sample analysis.

We report the unexpected pressure-induced and time-dependent nucleation and crystallisation of n-pentane from a 1 : 1 mixture of n-pentane and iso-pentane. The crystal structure of n-pentane at 3.3 GPa is reported; the 19.6% decrease in volume up to 3.3 GPa is caused by the significant reduction of voids within the structure. The study has wider implications for the separation of mixtures of organic compounds that have similar melting and boiling points, as well as the use of a 1 : 1 mixture of n-pentane and iso-pentane as a pressure-transmitting medium in high-pressure diffraction experiments.

Microbial competition for carbon sources is associated with disease suppression, and continuous mono-cropping stimulates certain patterns of carbon deposits. In this study, we investigated five fields from three ginger mono-cropping durations (over 35 years, approximately 15 years and 3 years) and two disease conditions (wilt-suppressive and wilt-conducive) at two collection time points (fallow and harvest). We measured the bacterial community and overall microbial carbon metabolism ability using high-throughput sequencing and Biolog EcoPlates. The results showed that the metabolic capabilities of soil microbes at harvest time were higher than at fallow time. The distribution of the bacterial community and the soil microbial metabolic diversity were significantly affected by both factors of cropping years and disease conditions at harvest time. Moreover, potentially beneficial microbes more enriched in wilt-suppressive soils than in wilt-conducive soils and l -arginine and 4-hydroxybenzoic acid were significantly metabolized in suppressive samples. We further confirmed that l -arginine and 4-hydroxybenzoic acid were only slightly metabolized by the pathogen. Taken together, these results suggest that the addition of l -arginine could enrich the beneficial microbes, while metabolism of 4-hydroxybenzoic acid could indicate the disease conditions of soil.

Variable-temperature single-crystal and powder X-ray diffraction techniques have been used to study the thermal and mechanical decomposition of the acetonitrile solvate of the cocrystal formed betw...

Surface molecularly imprinted polymer of solanesol (SA-SMIP) was prepared by reversed phase suspension polymerization using modified titanium dioxide (TiO2) as carrier, and operation conditions were investigated and optimized. Structures of modified TiO2 and SA-SMIP obtained at optimal conditions were characterized by Fourier transform infrared spectrometer adopting original TiO2 and non-surface molecularly imprinted polymer as reference. The SA-SMIP synthesized under optimal conditions displayed an excellent recognition of SA from the mixture of SA and triacontanol. The maximum separation degree of SA was 2.90. Finally, the adsorption kinetics and isotherm were investigated and analyzed. Adsorption kinetics results indicated that the adsorption of SA-SMIP to SA was a pseudo-second order process, and the adsorption of beginning and later stages was controlled by homogeneous particle diffusion and adsorption reaction process, respectively. Adsorption isotherm results documented hereby were two sorts of bonding sites, complete imprinted cavities and defective imprinted cavities. The adsorption for two bonding sites could be well lined up with the Langmuir model.

Based on snow-depth and measured runoff data in the 19 river basins of the cryosphere areas of China, changes in cold season snow depth (CSSD) and spring runoff, and the relationship between CSSD a...

The classical conclusions about the vehicle stability are usually drawn from the 2-DOF vehicle model. As more and more researchers begin to explore the complex dynamic characteristics of nonlinear and high degrees of freedom vehicle plane motion system, it is of value to intuitively reveal the global dynamic characteristics by objective quantitative indicators. Moreover, a new quantitative indicator, dissipation of energy, was proposed in 2021, and it is also worth further analyzing its rationality. For the above purposes, first of all, this paper briefly introduces the difference between the 2-DOF model and the high degree of freedom (≥3) model based on previous work. Secondly, this paper objectively discusses the stability characteristics of high degrees of freedom vehicle system from different aspects (dissipation of energy, longitudinal velocity, tire sideslip angle, convergence time) for the first time. In addition, the relationship between each indicator is systematically compared with the dissipation of energy, and their advantages and disadvantages are explained. Therefore, the main contributions of this paper are as follows: (1) This paper supplements previous conclusions on the dynamic characteristics of high-DOF vehicle plane motion system and helps researchers better understand the global dynamic characteristics from different perspectives. (2) This paper supplements previous discussions on the rationality and effectiveness of dissipation of energy method, and objectively reveals the relationship between dissipation of energy and stability. (3) This paper establishes a link between qualitative and quantitative methods. The vehicle system dynamics characteristics are presented from a variety of quantitative perspectives for the first time, supplementing the relevant research in the field of dynamics quantitative indicators.

The assembly of root-associated microbes during the seedling stage has strong impact on subsequent performance of crops. Major factors influencing this assembly are crop species identity and composition of potential root-colonizing microbes in the bulk soil. The latter can be modified by soil management, such as organic amendments. The incorporation of residues of cover crops before the start of the growing season of cash crops presents an interesting option for steering of root-associated seedling microbiomes as there is a wide range of cover crops species with different properties available for farmers. In a greenhouse study, we examined the effect of soil amendments with milled shoot and root materials of seven cover crop species (niger seed, phacelia, rapeseed, radish, vetch, black oat and buckwheat) on the assembly of root-associated bacteria and fungi of seedlings of four cash crop species (asparagus, carrot, onion and sugar beet). Field-grown cover crops material used for the study was collected at two time points (before and after winter) which had strong impact on plant elemental composition. The soil used for the study was a mixture of sandy arable soils with a history of soil-borne fungal diseases (Fusarium and Rhizoctonia). Within the context of a strong selection of root-associated microbes by cash crop species, we found significant modifying effects by cover crop materials. We show that cover crop elemental composition had a stronger effect than cover crop species identity. High quality residues (with low C/N ratio) caused profound shifts within root-associated Proteobacteria and increases in relative abundance of certain microbial groups such as Bacillaceae and Mortierellomycetes. These changes coincided with differences in establishment and survival of cash crop seedlings. Tolerance of sugar beet seedlings against the fungal pathogen Rhizoctonia solani was correlated with residues causing increases of root-associated Oxalobacteraceae, Bacillaceae and Mortierellaceae. However, the same residues increased Fusarium-induced failure of asparagus seed germination. This indicates that fine-tuning of cover crops amendments for different cash crops is required to realize enhanced functioning of root microbiomes.

Long-term monoculture cropping is usually accompanied by soil acidification and microbial community shifts. Soil aluminum ions are dissolved under acidic condition (pH < 5.0), and the resulting aluminum bioavailability can cause toxic effects in plants. In this study, we investigated the bacterial community compositions and aluminum toxicity in fields monocultured with ginger for 35 years, 15 years, and 1 year. Within these fields are ginger plants without and with ginger bacterial wilt disease. The results confirmed that the degree of aluminum toxicity in the diseased soil was more severe than that in the healthy soil. Continuous cropping can significantly increase the bacterial diversity and change the bacterial community composition of ginger rhizosphere soil. The relative abundance of plant growth-promoting rhizobacteria (PGPRs) was increased in the soils used for the continuous cropping of ginger. Additionally, aluminum toxicity had a significant positive correlation with Bacillus, Pseudomonas, Arthrobacter, and Serratia in healthy soils. Based on these results, aluminum stress may stimulate the increase of PGPRs (Bacillus, Pseudomonas, Arthrobacter, and Serratia), thereby alleviating ginger aluminum toxicity and bacterial wilt in extremely acidic soil (pH < 4.5).

Single crystals which exhibit mechanical flexibility are promising materials for advanced technological applications. Before such materials can be used, detailed understanding of the mechanisms and structural effects of bending are needed. Coordination polymer single crystal represent a fascinating class of mechanically flexible material; their bending contradicts existing models. Using single crystal X-ray diffraction and microfocus Raman spectroscopy, we study in atomic detail the high-pressure response of the plastically flexible coordination polymer [Zn(μ‐Cl)2(3,5‐dichloropyridine)2]n. In stark contrast to three-point bending, the quasi-hydrostatic compression of the single crystal is completely reversible, even following compression to over 9 GPa. A structural phase transition is observed at ca. 5 GPa. Ab initio DFT calculations show this transition to result from the pressure-induced softening of low frequency vibrations. This phase transition is not observed during three-point bending. Our combined experimental and theoretical high-pressure investigation propose slight compression at low levels of bending. However, our studies provide the first indication of overall disparate mechanical responses of bulk flexibility and quasi-hydrostatic compression. We suspect this to be a general feature of mechanically plastic materials.

The widespread use of biodiesel as a renewable fuel offers many potential advantages, but at the same time presents challenges for modern internal combustion engines, particularly for those that involve high-pressure injection of fuel into the combustion chamber. At the typical elevated pressures used in such engines, biodiesel can crystallise and block fuel filters and injection nozzles, thereby causing engine failure. In this study, optical studies and Raman spectroscopy of a typical biodiesel sample contained in a diamond-anvil cell show that biodiesel initially crystallises at ca. 0.2 GPa and then undergoes a series of structural changes on further increase of pressure. On account of the complex composition of biodiesel, this study focused on one of its main components – methyl stearate. Using a combination of Raman spectroscopy, X-ray powder diffraction and neutron powder diffraction, it was shown that methyl stearate exhibits rich polymorphic behaviour when subjected to elevated pressures up to 6.3 GPa. Under non-hydrostatic conditions, pressures as low as 0.1 GPa converted Form V to crystallites of Form III that typically adopt plate-like morphologies. This observation has implications for the pressure-induced crystallisation of biodiesel containing high proportions of methyl stearate because of the potentially serious consequences for blocking of injection nozzles in engines. Four phase transitions over the pressure range of 0.1 GPa to 6.3 GPa were also observed. Form III was recovered on decompression to ambient pressure. High-pressure neutron powder diffraction studies of a perdeuterated sample showed that Form V persisted up to 3.11 GPa. This contrast in behaviour between the X-ray and neutron studies may be a consequence of deuteration, or of compression under non-hydrostatic versus hydrostatic conditions.

The near-surface soil freeze state is affected by global warming, and its changes have profound effects on landscapes, ecosystems and hydrological processes. On the basis of daily soil freeze observational data at 476 meteorological stations over 50 freezing years from September 1, 1961 to August 31, 2011, the spatial distributions and temporal variations of the near-surface soil freeze state were estimated using five freeze variables (first date, last date, maximum seasonally frozen depth, duration and actual number of freeze days) across China, which was divided into three regions (eastern China, northwestern China and the Qinghai-Tibetan Plateau (QTP)). The near-surface soil freeze state varied greatly across China. The QTP has an earlier freeze, later thaw, longer freeze days and deeper seasonally frozen depth than the other two regions. The spatial distributions of the near-surface soil freeze state can be explained largely by altitude in northwestern China and on the QTP, whereas they can be explained by latitude in eastern China. The near-surface soil freeze state has changed significantly over 50 freezing years. On average across China over the study period, the first date of freezing was delayed by approximately 10 ± 1 days with a rate of 0.20 ± 0.02 days/year, the last date advanced by approximately 18 ± 2 days with a rate of 0.36 ± 0.04 days/year, the duration and the number of freeze days decreased by 28 ± 2 and 23 ± 2 days with rates of 0.56 ± 0.04 and 0.45 ± 0.04 days/year, respectively, and the maximum seasonally frozen depth decreased by 20 ± 3 cm with a rate of 0.41 ± 0.06 cm/year. The change in the freeze variables is relatively large in high-latitude and high-altitude regions.

The equation of state, dynamical properties, and molecular-scale structure of squalane and mixtures of poly-α-olefins at room temperature are studied with a combination of state-of-the-art, high-pressure experiments and molecular-dynamics simulations. Diamond-anvil cell experiments indicate that both materials are non-hydrostatic media at pressures above ∼1 GPa. The equation of state does not exhibit any sign of a first-order phase transition. High-pressure x-ray diffraction experiments on squalane show that there are no Bragg peaks, and hence, the apparent solidification occurs without crystallization. These observations are complemented by a survey of the equation of state and dynamical properties using simulations. The results show that molecular diffusion is essentially arrested above about 1 GPa, which supports the hypothesis that the samples are kinetically trapped in metastable amorphous-solid states. The shear viscosity becomes extremely large at very high pressures, and the coefficient governing its increase from ambient pressure is in good agreement with the available literature data. Finally, simulated radial distribution functions are used to explore the evolution of the molecular-scale structure with increasing pressure. Subtle changes in the short-range real-space correlations are related to a collapse of the molecular conformations with increasing pressure, while the evolution of the static structure factor shows excellent correlation with the available x-ray diffraction data. These results are of indirect relevance to oil-based lubricants, as the pressures involved are comparable to those found in engines, and hence, the ability of lubricating thin films to act as load-bearing media can be linked to the solidification phenomena studied in this work.

Bacteriophage T7 infects Escherichia coli and evades the host restriction/modification system. The Ocr protein of T7 was shown to exist as a dimer mimicking DNA and to bind to host restriction enzymes, thus preventing the degradation of the viral genome by the host. Here we report that Ocr can also inhibit host transcription by directly binding to bacterial RNA polymerase (RNAP) and competing with the recruitment of RNAP by sigma factors. Using cryo electron microscopy, we determined the structures of Ocr bound to RNAP. The structures show that an Ocr dimer binds to RNAP in the cleft, where key regions of sigma bind and where DNA resides during transcription synthesis, thus providing a structural basis for the transcription inhibition. Our results reveal the versatility of Ocr in interfering with host systems and suggest possible strategies that could be exploited in adopting DNA mimicry as a basis for forming novel antibiotics., eLife digest Bacteria and viruses have long been fighting amongst themselves. Bacteriophages are a type of virus that invade bacteria; their name literally means ‘bacteria eater’. The bacteriophage T7, for example, infects the common bacteria known as Escherichia coli. Once inside, the virus hijacks the bacterium’s cellular machinery, using it to replicate its own genetic material and make more copies of the virus so it can spread. At the same time, the bacteria have found ways to try and defend themselves, which in turn has led some bacteriophages to develop countermeasures to overcome those defences. Many bacteria, for example, have restriction enzymes which recognise certain sections of the bacteriophage DNA and cut it into fragments. However, the T7 bacteriophage has one well-known protein called Ocr which inhibits restriction enzymes. Ocr does this by mimicking DNA, which led Ye et al. to wonder if it could also interrupt other vital processes in a bacterial cell that involve DNA. Transcription is the first step in a coordinated process that turns the genetic information stored in a cell’s DNA into useful proteins. An enzyme called RNA polymerase decodes the DNA sequence into a go-between molecule called messenger RNA, and it was here that Ye et al. thought Ocr might jump in to interfere. To begin, Ye et al. examined the structure of Ocr when it binds to RNA polymerase using an imaging technique called cryo-electron microscopy. Ocr has been well-studied before, its structure previously described, but not when attached to RNA polymerase. The analysis showed that Ocr gets in the way of specific molecules, called sigma factors, that show RNA polymerase where to start transcription. Ocr binds to RNA polymerase in exactly the same pocket as part of sigma factors do, which is also the place where DNA must be to be decoded to make messenger RNA. Ye et al. then performed experiments to show Ocr interfering with binding to RNA polymerase did indeed disrupt transcription. This means Ocr is quite versatile as it interferes with the RNA polymerase of the bacterial host and its restriction enzymes. Ocr’s strategy of mimicking DNA to interrupt transcription could be adopted as an approach to develop new antibiotics to stop bacterial infections. DNA transcription is an essential cellular process – without it, no cell can replicate and survive – and RNA polymerase is already a validated target for drugs. Following Ocr’s lead could provide a new way to stop infections, if the right drug can be designed to fit.

In this study, heat and relative humidity (HRH) treatment was applied in highland barley for γ-aminobutyric acid (GABA) accumulation. Tibetan highland barley cultivars (25) were selected for comparison and analysis. HRH treatment could accumulate GABA in several hours with low moisture content and high temperature, and the grains were treated for 2.5 h at 65 °C in this study. The GABA content of processed grains under HRH optimal condition ranged from 26.91 to 76.28 mg·100 g−1, which was significantly higher than the initial content (12.78–43.00 mg·100 g−1). The highest GABA accumulation capacity was observed in two-row yellow cultivars (YT1), increasing from 36.52 to 76.28 mg·100 g−1. Correlation analysis showed that the accumulation of GABA after HRH treatment was positively and significantly (p < 0.05) correlated with the contents of protein (0.52), total free amino acids (0.68), threonine (0.53), serine (0.51), glutamate (0.69), glycine (0.49), alanine (0.46), cysteine (0.57), tyrosine (0.50), lysine (0.53), proline (0.40), and glutamate decarboxylase (GAD) activity (0.62), which were closely related to GABA-shunt pathway. The polyamines contents, diamine oxidase (DAO) and polyamine oxidase (PAO) activities, as the substrates and critical enzymes of polyamine degradation pathway, showed no significant correlation with GABA accumulation. The results suggested that the main pathway of GABA accumulation in highland barley under HRH treatment was GABA-shunt pathway.

The increase in low flows (winter discharge and minimum monthly discharge), caused primarily by permafrost degradation, is common in high‐latitude permafrost regions, whereas the dynamics of low flows in high‐altitude permafrost regions remain largely unknown. Long‐term discharge data from 28 unregulated catchments in western China were analysed, and the findings showed that winter discharge/minimum monthly discharge significantly increased (p ≤ 0.1) in 82/82%, 55/64%, and 0/0% of the catchments in the higher‐latitude mountain permafrost regions (Tienshan Mountains), mid‐latitude mountain permafrost regions (Qilian Mountains), and mid‐ to low‐latitude plateau permafrost regions (the source regions of the Yangtze and Yellow rivers), respectively. The differences in permafrost type and the distribution of permafrost and alpine cold desert (which is similar to tundra) were found to be the main causes for the different responses in the low flows. The rate of change of low flows (winter discharge and minimum monthly discharge) was negatively and linearly correlated with permafrost coverage when coverage was less than 40% of the catchment area, whereas the low flows changed only slightly when the permafrost coverage exceeded 40%. A significant thickening of the active layer increased the low flows in the lower permafrost‐covered catchments, which are dominated by warm permafrost. However, in the higher permafrost‐covered catchments with cold permafrost and a cold climate, only an increase in permafrost temperature (without a notable thickening of the active layer) occurred, resulting in non‐significant changes in low flows.

With the popularity of the automatic precipitation gauges in national weather stations, testing their performance and adjusting their measurements are top priorities. Additionally, because different climatic conditions may have different effects on the performance of the precipitation gauges, it is also necessary to test the gauges in different areas. This study mainly analyzed precipitation measurements from the single-Alter-shielded TRwS204 automatic weighing gauge (TRwSSA) relative to the adjusted manual measurements (reference precipitation) from the Chinese standard precipitation gauge in a double-fence wind shield (CSPGDF) in the Hulu watershed in the Qilian Mountains, China. The measurements were compared over the period from August 2014 to July 2017, and the transfer function derived from the work by Kochendorfer et al. (2017a) for correcting wind-induced losses was applied to the TRwSSA measurements. The results show that the average loss of TRwSSA measurements relative to the reference precipitation decreased from 0.55 mm (10.7%) to 0.51 mm (9.9%) for rainfall events, from 0.35 mm (8.5%) to 0.22 mm (5.3%) for sleet events, and from 0.49 mm (18.9%) to 0.33 mm (12.7%) for snowfall events after adjustment. The uncorrected large biases of TRwSSA measurements are considered to be mainly caused by specific errors of TRwSSA, different gauge orifice area and random errors. These types of errors must be considered when comparing precipitation measurements for different gauge types, especially in the mountains.

To study the influence of the preparation method on Cu active sites and the reaction pathway in NO reduction by NH3 over Cu–SSZ-13, three kinds of catalysts (Cu ion-exchanged SSZ-131, one-pot synthesis Cu–SSZ-132, and Ce0.017–Fe0.017/Cu–SSZ-13 [Ce and Fe ion exchange on the basis of Cu–SSZ-132]) were prepared. In situ diffuse reflectance infrared Fourier transform spectroscopy and H2 temperature program reduction were used to study the differences in the reaction pathways and Cu active sites over the three kinds of catalysts. Density functional theory was employed to study the effect of active sites on the reaction pathway. In situ DRIFTS showed that the reaction pathway on Cu–SSZ-131 during NO oxidation was different from that on Cu–SSZ-132 and Ce0.017–Fe0.017/Cu–SSZ-13. The difference was that intermediate NO2 was involved in the selective catalytic reduction reaction on Cu–SSZ-131, whereas NO2 was not found during the reaction process on Cu–SSZ-132 and Ce0.017–Fe0.017/Cu–SSZ-13. H2–TPR studies revealed that the three catalysts had different Cu active sites, which were located in the six-membered ring, eight-membered ring, and CHA cage. On the basis of DFT studies, NO and O2 were more conducive to form nitrate when the Cu species was on the six- and eight-membered rings; by contrast, NO and O2 were more conducive to form NO2 in the cage. These results showed that different preparation methods led to various Cu active sites, and varying Cu active sites could lead to different NO oxidation processes.

Application of soil amendments has been wildly used to increase soil pH and control bacterial wilt. However, little is known about causal shifts in the rhizosphere microbial community of crops, especially when the field naturally harbors the disease of bacterial wilt to tobacco for many years due to long-term continuous cropping and soil acidification. In this study, biochar (CP), lime (LM), oyster shell powder (OS) and no soil amendment additions (Control; CK) were assessed for their abilities to improve the soil acidification, change the composition of rhizosphere soil bacterial communities and thus control tobacco bacterial wilt. The results showed that oyster shell powder significantly increased soil pH by 0.77 and reduced the incidence of tobacco bacterial wilt by 36.67% compared to the control. The Illumina sequencing -based community analysis showed that soil amendment applications affected the composition of rhizosphere bacterial community and increased the richness and diversity. In contrast, the richness and diversity correlated negatively to disease incidence. Using LEfSe analyses, 11 taxa were found to be closely related with disease suppression, in which Saccharibacteria, Aeromicrobium, and Pseudoxanthomonas could be potential indicators of disease suppression. Our results suggested that the suppression of bacterial wilt after the application of soil amendments (especially oyster shell powder) was attributed to the improved soil pH and increased bacterial richness and diversity. Electronic supplementary material The online version of this article (10.1007/s00253-018-9347-0) contains supplementary material, which is available to authorized users.

Sourdough is widely used for the preparation of traditional sourdough breads in Europe and as an important inoculum for steamed buns prepared in Asian countries, especially China. This study aims to characterize Chinese traditional sourdoughs in terms of their taxonomic compositions, physicochemical characteristics, bacterial diversity and functional features. Thirty geographically diverse sourdoughs were collected from three regions across China. High-throughput sequencing and bioinformatics were used to characterize the bacterial diversity of the sourdoughs from the different sampling sites. The results showed that the West group was significantly different from the North and South groups in the dominant genera (mainly Lactobacillus, Pediococcus and Leuconostoc) and metabolic pathways (metabolism of terpenoids and polyketides, MTP, and xenobiotics biodegradation and metabolism, XBM), whereas samples from the North and South groups were not significantly different from each other. This is the first report of the genus Clostridium in sourdough and the first report of metabolic pathways related to MTP and XBM in sourdough. This research provides a thorough description and analysis of the relationship between bacterial diversity and geographic region in sourdough.

Mycotoxins are secondary metabolites produced by fungal species and have been reported to be carcinogenic, genotoxic, teratogenic, nephro- and hepatotoxic. Economic losses and health concerns due to mycotoxins occur at all levels of food and feed production, and this has attracted research interest towards exploring novel approaches to decontaminate and/or detoxify mycotoxin-contaminated food and feed. Therefore, we reviewed various strategies for the detoxification of mycotoxins, including pre-harvest prevention strategies and post-harvest detoxification procedures. Strategies for pre-harvest prevention include appropriate environmental factors, good agricultural and manufacturing practices, and favourable storage practices. For post-harvest detoxification strategies, physical, chemical, biological and other developing innovative strategies are discussed. This review is meant to be beneficial to the food industry and to contribute to assuring pre- and post-harvest management and processing practices that maximize consumer safety.

The crystallisation of methyl stearate under a range of crystallisation conditions has been studied and three new polymorphs have been identified and structurally characterised. Form III (monoclinic, space group Cc, Z = 8) was obtained at room temperature by slow evaporation of a saturated solution in CS2. Form IV (monoclinic, space group C2/c, Z = 4) was obtained by slow cooling of the melt. Both structures were characterised by single crystal X-ray diffraction. Form V (monoclinic, space group Cc, Z = 4) was obtained from the melt by rapid cooling. X-ray and neutron powder diffraction methods were employed in the determination of this structure. Form V shows highly anisotropic thermal expansion, with expansion along the crystallographic b-axis being substantially greater than along the other two axes.

This study investigates the impact of China’s Green Credit Guidelines on the technological innovations of heavily polluting enterprises. This study uses data obtained from the CSMAR database (2007–2018) and China Marketization Index Report by Province 2018 and uses the Green Credit Guidelines as a quasi-natural experiment. The sample was divided into an experimental group and a control group; the experimental group disclosed environmental and sustainable development information, while the control group did not. This study’s primary finding is that the Green Credit Guidelines can improve the level of technological innovation of heavily polluting enterprises and have a greater impact in areas with high levels of marketization, indicating that the Green Credit Guidelines have a positive effect on the technological innovation of heavily polluting enterprises. This provides China with an experience constructing relevant policies and regulations and provides empirical evidence regarding the technological innovations of heavily polluting enterprises from the perspective of factor market distortions and the Porter hypothesis.

Summary Competition is a major type of interaction between fungi and bacteria in soil and is also an important factor in suppression of plant diseases caused by soil‐borne fungal pathogens. There is increasing attention for the possible role of volatiles in competitive interactions between bacteria and fungi. However, knowledge on the actual role of bacterial volatiles in interactions with fungi within soil microbial communities is lacking. Here, we examined colonization of sterile agricultural soils by fungi and bacteria from non‐sterile soil inoculums during exposure to volatiles emitted by soil‐derived bacterial communities. We found that colonization of soil by fungi was negatively affected by exposure to volatiles emitted by bacterial communities whereas that of bacteria was barely changed. Furthermore, there were strong effects of bacterial community volatiles on the assembly of fungal soil colonizers. Identification of volatile composition produced by bacterial communities revealed several compounds with known fungistatic activity. Our results are the first to reveal a collective volatile‐mediated antagonism of soil bacteria against fungi. Given the better exploration abilities of filamentous fungi in unsaturated soils, this may be an important strategy for bacteria to defend occupied nutrient patches against invading fungi. Another implication of our research is that bacterial volatiles in soil atmospheres can have a major contribution to soil fungistasis.

Patulin contamination is a serious issue that restricts the development of the global fruit processing industry. Yeasts adsorb patulin more effectively than other microbial adsorbents, and this adsorption process depends mainly on the function of the cell wall. The present study examined the effect of exogenous calcium, in concentrations ranging from 0 to 1 mol/L, on

Precipitation and temperature in the Qilian Mountains and the Hexi oasis are changing with climate change. The characteristics and control factors of these changes are not well understood, affecting the ability to allocate water resources in this area judiciously. We analyzed the annual and seasonal variability in precipitation and temperature during 1960–2016 using monthly data from 25 national meteorological stations in the Qilian Mountains. Results showed that precipitation increased by 6.2, 4.1, and 8.9 mm/decade for the whole regions (including oasis and mountains), oasis, and mountains, respectively. Variability in summer precipitation made the greatest contribution to the annual change in precipitation. Moreover, the increment in precipitation was amplified with elevation. Enhanced westerly circulation and increased water vapor were the factors responsible for the increased precipitation in the study area. Temperature in the whole regions, oasis, and mountains increased at the rate of 0.32, 0.32, and 0.33 °C/decade, respectively. Changes in temperature were greatest in winter, with 0.47, 0.36 and 0.50 °C/decade in the whole regions, oasis, and mountains, respectively; changes in winter temperature made the greatest contribution to the annual temperature changes. Seasonal differences in carbon dioxide concentration may have caused the seasonal differences in the rate of temperature increase. The annual increase in temperature was mainly due to Siberian High, and Arctic Oscillation, carbon emissions and decreased cloud cover in the study area. The study results will help evaluate climatic hazards and contribute to development of water resources management strategies such as supplementary irrigation.

Obtaining the fingerprints of polysaccharides was known to be notoriously difficult by ambient mass spectrometry due to their resistance for desorption and ionization. Ambient mass spectrometry technology has recently been recognized as a quick analysis tool for obtaining fingerprints, which is attributed to its characteristics of no sample pretreatment and easy operation under atmospheric pressure. However, it still remains a challenge for accurate identification of the fingerprints of macromolecular polysaccharides by ambient micro-fabrication glow discharge plasma (MFGDP). In this study, a simplified methylation method was introduced to realize rapid analysis of polysaccharide mixture by MFGDP with the assistance of a temperature-programmed system (TPS). At the optimal temperature of TPS, oligosaccharides, plant polysaccharides and polysaccharide mixtures were all well characterized by TPS-MFGDP. In the proposed method, the characteristic [M + NH4] + adduct ions of oligosaccharides ions of oligosaccharides that are difficult for other ambient mass spectrometric methods were abundantly produced, making it possible to simultaneously identify a mixture of five or more polysaccharides. In addition, a supervised classification model which based on MS spectra, was used to classify seven typical hypoglycemic polysaccharides with excellent sensitivity, specificity and accuracy, indicating the good classification performance of the RF model constructed. Thus, the proposed mass spectroscopic method provides a cost effective, accurate and high throughput tool for identification and classification of polysaccharides, which is beneficial for studying the biological activity of polysaccharides.