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Biological control is an effective measure in the green control of rice diseases. To search for biocontrol agents with broad-spectrum and high efficiency against rice diseases, in this study, a strain of antagonistic bacterium BR-01 with strong inhibitory effect against various rice diseases was isolated from

A MOF-based bio-bar code material was synthesized and firstly applied to develop an electrochemical streptomycin (STR) aptasensor. By using MOF-based bio-bar code and enzyme-assisted target recycling for dual-signal amplification, highly sensitive detection of STR was achieved. The sensing surface was simply fabricated by immobilizing a mixed monolayer of thiolated cDNA/aptamer duplexes (dsDNA) and 6-mercapto-1-hexanol (MCH) on the gold nanoparticle modified screen printed carbon electrode (Au/SPCE). The presence of target STR caused highly efficient removal of the aptamers from dsDNA assisted by Exo I enzyme. Then MOF-based bio-bar codes were backfilled to achieve the adsorption of electroactive Ru(NH3)63+ (RuHex) on electrode surface. The electrochemical signal of the surface-confined RuHex was used for quantitation. The analytical performance for STR was satisfactory with a wide linear range of 0.005–150 ng mL−1, a low detection limit of 2.6 pg mL−1 and a good selectivity towards other three antibiotics. Moreover, the application of this aptasensor for determination of STR in real milk samples was also realized. With these merits, this dual-signal amplification assay might provide one of the effective ways for food safety monitoring.

The type VI secretion system (T6SS), a multifunctional protein secretion device, plays very important roles in bacterial killing and/or virulence to eukaryotic cells. Although T6SS genes have been found in many Xanthomonas species, the biological function of T6SSs has not been elucidated in most xanthomonads. In this study, we identified two phylogenetically distinct T6SS clusters, T6SS1 and T6SS2, in a newly sequenced Chinese strain GX01 of Xanthomonas oryzea pv. oryzicola (Xoc) which causes bacterial leaf streak (BLS) of rice (Oryza sativa L.). Mutational assays demonstrated that T6SS1 and T6SS2 are not required for the virulence of Xoc GX01 on rice. Nevertheless, we found that T6SS2, but not T6SS1, played an important role in bacterial killing. Transcription and secretion analysis revealed that hcp2 gene is actively expressed and that Hcp2 protein is secreted via T6SS. Moreover, several candidate T6SS effectors were predicted by bioinformatics analysis that might play a role in the antibacterial activity of Xoc. This is the first report to investigate the type VI secretion system in Xanthomonas oryzae. We speculate that Xoc T6SS2 might play an important role in inter-bacterial competition, allowing this plant pathogen to gain niche advantage by killing other bacteria.

Xanthomonas oryzae pv. oryzicola (Xoc) depends on its type III secretion system (T3SS) to translocate type III secreted effectors (T3SEs), including transcription activator-like effectors (TALEs) and non-transcription activator-like effectors (non-TALEs), into host cells. T3SEs can promote the colonization of Xoc and contribute to virulence by manipulating host cell physiology. We annotated 25 genes encoding non-TALEs in Xoc strain GX01, an isolate from Guangxi in the South China's rice growing region. Through systematic mutagenesis of non-TALEs, we found that xopN, the virulence contribution of which was previously unknown for Xoc, significantly contributes to the virulence of Xoc GX01, as does avrBs2.

This paper analyzes the key issues in the training of computer professionals under the new situation, creatively thinks about computer professional education, and puts forward the concept of diversified talent training. Using engineering education professional certification as a starting point, it discusses the construction of computer majors under the background of artificial intelligence. This paper provides new ideas for talent training, and designs a talent training program to better cultivate innovative talents in computer science that can adapt to the development of the times and face the needs of applications.

Background Xanthomonas oryzae (Xo) is one of the important pathogenic bacterial groups affecting rice production. Its pathovars Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc) cause bacterial blight and bacterial leaf streak in rice, respectively. Xo infects host plants by relying mainly on its transcription activator-like effectors (TALEs) that bind to host DNA targets, named effector binding elements (EBEs), and induce the expression of downstream major susceptibility genes. Blocking TALE binding to EBE could increase rice resistance to the corresponding Xo. Findings We used CRISPR/Cas9 to edit the EBEs of three major susceptibility genes (OsSWEET11, OsSWEET14 and OsSULTR3;6) in the rice varieties Guihong 1 and Zhonghua 11. Both varieties have a natural one-base mutation in the EBE of another major susceptibility gene (OsSWEET13) which is not induced by the corresponding TALE. Two rice lines GT0105 (from Guihong 1) and ZT0918 (from Zhonghua 11) with target mutations and transgene-free were obtained and showed significantly enhanced resistance to the tested strains of Xoo and Xoc. Furthermore, under simulated field conditions, the morphology and other agronomic traits of GT0105 and ZT0918 were basically the same as those of the wild types. Conclusions In this study, we first reported that the engineering rice lines obtained by editing the promoters of susceptibility genes are resistant to Xoo and Xoc, and their original agronomic traits are not affected.

Xanthomonas is a well-studied genus of bacterial plant pathogens whose members cause a variety of diseases in economically important crops worldwide. Genomic and functional studies of these phytopathogens have provided significant understanding of microbial-host interactions, bacterial virulence and host adaptation mechanisms including microbial ecology and epidemiology. In addition, several strains of Xanthomonas are important as producers of the extracellular polysaccharide, xanthan, used in the food and pharmaceutical industries. This polymer has also been implicated in several phases of the bacterial disease cycle. In this review, we summarise the current knowledge on the infection strategies and regulatory networks controlling virulence and adaptation mechanisms from Xanthomonas species and discuss the novel opportunities that this body of work has provided for disease control and plant health., Here, we discuss the current knowledge surrounding regulatory networks and systems that control virulence and adaption mechanisms in Xanthomonas species. Additionally, we detail how study of these pathogens has provided novel opportunities for disease control and plant health.

In this work, a sensitive electrochemical method for bleomycin (BLM) determination was reported on the basis of BLM-mediated activation of Zn2+-dependent DNAzyme and the adsorption of signal probes by a metal-organic framework (MOF) modified electrode. Two hairpin DNAs were employed in this protocol, one (HP1) for BLM recognition and one (HP2) for amplified signal output. The presence of BLM and Fe2+ caused the formation of BLM-Fe (II) complex to cleave HP1, releasing DNAzyme fragments, which could further hybridize with substrate HP2 to form a partial double-stranded DNA duplex and enable the activation of Zn2+-dependent DNAzyme with the coexistence of Zn2+. The Zn2+-dependent DNAzyme catalyzed the cyclic cleavage of magnetic beads (MB)-immobilized HP2 to release massive DNA fragments with a Fc-labeled- terminal, which could be used for BLM quantification through electrochemical measurement after their adsorption on a MOF modified electrode. Attributing to the high catalytic efficiency of DNAzyme and excellent electrochemical performance of MOF modified electrode, our method revealed an impressive limit of detection as low as 4 pM BLM with a linear range of 5-2000 pM. Besides, the easy synthesis of MOF without further modification and the easy way of adsorption for signal achievement facilitated the operation process. In virtue of the high sensitivity, selectivity and the simple-to-implement features, this method is believed to hold a great promising application for BLM determination in biomedical and clinical study.

Laser is used for remote charging of UAV instead of sunlight to improve charging power, continuous charging performance and endurance of UAV. Laser alignment is one of the key technologies for laser charging. On the basis of briefly describing the composition and working process of the laser charging system, the method, module composition, working process and key process based on beacon laser alignment are emphatically analyzed. Combined with the whole working process of the laser charging system, the error factors affecting the charging accuracy are analyzed, and the reasonable error distribution is carried out to provide theoretical basis for the system realization.

To study the dynamic performance of middle locomotives and their couplers of 20,000t heavy haul combined train under pressing coupler force, the longitudinal dynamic characteristics of train’s electric braking, cyclic braking and emergency braking on straight track were calculated with the longitudinal train dynamics (LTD) simulation package TDEAS, the coupler force of middle locomotives were obtained and sent to multi-body system (MBS) model of train established in package SIMPACK, and then the dynamic behaviour of middle locomotives and their couplers under pressing coupler force were studied. The results show that under the pressing force in straight track, the vertical dynamic performance of locomotive will be influenced in certain degree, the guiding wheelsets will upload while the rear wheelsets unload, the more the pressing force is, the greater the upload and unload will be. There is less influence on lateral dynamic under straight track condition.

A number of species of bacteria from the genus Burkholderia have been shown to be causal agents of diseases of rice. These diseases, caused by Burkholderia glumae, B. gladioli and B. plantarii, are becoming increasingly common across the globe. This is particularly so for B. glumae, whose ability to grow at elevated temperatures suggests that it may become a prevalent problem in an era of global warming. Despite the increasing threat to rice, relatively little is known about the virulence mechanisms employed by these pathogens. Work over the last 5 years has provided an increasing insight into these factors and their control by environmental and other cues. In addition, the determination of a number of genome sequences has allowed bioinformatic predictions of further possible mechanisms, which can now be investigated experimentally. Here, we review recent advances in the understanding of virulence of Burkholderia to rice, to include discussion of the roles of toxins, type II secreted enzymes, type III secreted effectors and motility as well as their regulation by quorum sensing, two-component systems and cyclic di-GMP signalling. Finally, we consider a number of approaches for the control of bacterial virulence through the modulation of quorum sensing and toxin degradation.

A simple route for the in situ preparation of catalytically active Ag nanoparticles (NPs) in hydrogel networks has been developed. The electronegativity of the amide and carboxyl groups on the poly(acrylamide-co-acryl acid) chains caused strong binding of the Ag+ ions which made the ions distribute uniformly inside the hydrogels. When the Ag+ loaded hydrogels were immersed in NaBH4 solution, the Ag+ ions on the polymer networks were reduced to Ag NPs. The resultant hydrogel showed good catalytic activity for the reduction of a common organic pollutant, 4-nitrophenol, with sodium borohydride. A kinetic study of the catalytic reaction was carried out and a possible reason for the decline of the catalytic performance with reuse is proposed.

The black rot pathogen Xanthomonas campestris pv. campestris (Xcc) is a model organism for the study of plant bacterial pathogenesis mechanisms. In bacteria, σ factors serve as important regulatory elements that respond to various environmental signals and cues. Though Xcc encodes 15 putative σ factors little is known about their roles. As an approach to identify the potential role of each σ factor, we constructed mutations in each of the σ-factor genes as well as generating mutants deficient in multiple σ factors to assess these regulators potential additive functions. The work identified two σ70 factors essential for growth. Furthermore, the work discovered a third σ70 factor, RpoE1, important for virulence. Further studies revealed that RpoE1 positively regulates the expression of the hrp gene cluster that encodes the type III secretion system (T3SS) which determines the pathogenicity and hypersensitive response of Xcc on plants. In vivo and in vitro studies demonstrated that RpoE1 could bind to the promoter region and promote transcription of hrpX, a gene encoding a key regulator of the hrp genes. Overall, this systematic analysis reveals important roles in Xcc survival and virulence for previously uncharacterized σ70 factors that may become important targets for disease control.

With the development of our economy, highway becoming more and more important for our lives. While the construction of the highway will cause many geo-hazards such as landslide, Collapse, Debris Flow and loess collapse etc. , based on the highway of S208, the types and character were analyzed in The paper, then their hazards were evaluated, it can be supplied a necessary basement for letter prediction and evaluation and comprehensive zoning evaluation.

Increase in world population is usually followed by growing demand for food and increasingly higher requirements for the quality of food. The existing crops may require immediate improvement and optimization in order to adjust to market demands and the deteriorating environment. Genome editing breeding, a relatively advanced technology method that appeared in recent years, can accurately edit i.e. insert, delete or replace genes and directionally modify crops, by changing the plant's heredity and performance. Currently, some of the modern genome editing approaches has been applied rather widely in crop breeding e.g. zinc finger nuclease (ZFN), transcription activator-like effector nuclease (TALEN) and Clustered regularly interspaced short palindromic repeats/CRISPR associated protein (CRISPR/Cas). While reviewing the principles of the above genome editing technologies and their research progress in crop improvement, this paper will discuss the commercial application and future development of these technol...

Elastic-plastic finite element model of high strength aluminum alloy plate with long and short penetrating cracks in the center was built. Based on the model, tension and compression loading simulation was conducted. The analysis shows that the compressive stress has a significant effect on the crack tip plastic zone and fatigue crack propagation.

The colloidal crystal template or opal with a closed-packed face centered cubic (fcc) lattice was prepared from monodisperse polystyrene (PS) microspheres by gravity sedimentation, and it was used for the fabrication of polyaniline hybrid with inverse opal structure. The template provided void space for the infiltration of Bi2Te3 and monomer that was then in situ polymerized to polyaniline. The opal composite was then soaked in toluene for completely removing PS microspheres to form porous polyaniline hybrid with inverse opal structure. The PS microspheres were replaced by air microspheres, which interconnected each other through the windows on the polyaniline hybrid wall. Both the wall and the air void constitute continuous phases. The polyaniline hybrid with inverse opal structure was observed with scanning electronic microscopy.

Earthquake can cause heavy casualties and property losses immediately, and induced a mass of secondary mountainous disasters such as collapse, landslide and debris flow. Collapse and landslide provide abundant incompact solid matter for movement of debris flow directly, which makes the debris flow ravines be active in a long period in the future. Taking one debris flows on Bailong River as an example. Based on the analysis of the valley features and the forming condition scientific prediction for the trend of the debris flow activities and estimates the hazards situations have been achieved.

A simple method to fabricate clean Au–Pd nanoparticles on graphene oxide (Au–Pd NPs/GO) without using any reducing agent or surfactant has been developed. GO simultaneously reduced the Au and Pd precursors to form a stable suspension of the Au–Pd NPs/GO. The nanoparticles were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and inductively coupled plasma. The Au–Pd NPs/GO exhibited catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol and for the Suzuki–Miyaura coupling reaction of chlorobenzene and phenylboronic acid in aqueous media.

Highlights • A panel of PEDV structural and nonstructural proteins were expressed. • These PEDV antigens were tested for reactivity with sera from PEDV-infected pigs. • 851 porcine sera were analyzed by ELISA with antigens showing immune-reactivity. • Pattern of neutralizing antibody was more similar to that of IgA in weaning piglets. • ORF3C and E in addition to S1 can be used as diagnostic markers for serologic detection., Given the highly contagious and acute nature of porcine epidemic diarrhea (PED), especially in piglets, there is an urgent need for the development of rapid and sensitive diagnostic assays. The diagnostic potentials of specific porcine epidemic diarrhea virus (PEDV) accessory and nonstructural proteins, if any, have not yet been investigated. In order to determine and compare which of the viral proteins may be useful as diagnostic antigens, whole virus (WV) particles and a panel of structural and nonstructural PEDV proteins [spike subunit 1 (S1), the C-terminal part of ORF3 (ORF3C), envelope (E), nonstructural protein 1 (Nsp1), Nsp2, Ac (acidic domain of Nsp3), and ADRP (ADP-ribose-1-monophosphatase domain of Nsp3), expressed individually in bacterial and/or mammalian cells] were tested for reactivity with sera from PEDV-infected pigs by ELISA and/or western blot analysis. According to western blots, serum antibody interactions with the S1 protein were relatively more sensitive and specific than ORF3C, E and Ac. Furthermore, a total of 851 serum samples from diarrheal pigs of different ages were analyzed by ELISA, with most showing immune-reactivity towards the WV, S1, ORF3C, and E proteins. The earliest IgG antibody response was observed in the one-week-old piglets, with similar antibody ontogeny and patterns of seroconversion for S1, ORF3C, E, and WV antigens. In addition, the pattern of neutralizing antibody was more similar to that of IgA in weaning piglets after PEDV infection. Collectively, these data provide more reliable information on the host immune response to different viral proteins, which will be useful for development of novel serological assays and for design of vaccines that better stimulate protective immunity.

The Gram-negative bacterium Xanthomonas oryzae pv. oryzicola (Xoc) is the causal agent of rice bacterial leaf streak (BLS), one of the most destructive diseases of rice (Oryza sativa L.) that is the important staple crop. Xoc can invade host leaves via stomata and wounds and its type three secretion system (T3SS) is pivotal to its pathogenic lifestyle. In this study, using a novel dual RNA-seq approach, we examined transcriptomes of rice and Xoc in samples inoculated with wild type Xoc GX01 and its T3SS defective strain (T3SD), to investigate the global transcriptional changes in both organisms. Compared with T3SD strain, rice inoculated with wild type Xoc GX01 resulted in significant expression changes of a series of plant defence related genes, including ones altered in plant signalling pathway, and downregulated in phenylalanine metabolism, flavonoid and momilactone biosynthesis, suggesting repression of plant defence response and reduction in both callose deposition and phytoalexin accumulation. Also, some known transcription activator-like effector (TALE) targets were induced by Xoc GX01, e.g. OsSultr3;6 which contributes to rice susceptibility. Some cell elongation related genes, including several expansin genes, were induced by GX01 too, suggesting that Xoc may exploit this pathway to weaken cell wall strength, beneficial for bacterial infection. On the other hand, compared with wild type, the T3SD strain transcriptome in planta was characterized by downregulation of ATP, protein and polysaccharide synthesis, and upregulation of antioxidation and detoxification related genes, revealing that T3SD strain faced serious starvation and oxidation stresses in planta without a functional T3SS. In addition, comparative global transcript profiles of Xoc in planta and in medium revealed an upregulation of virulence factor synthesis and secretion in planta in favour of bacterial infection. Collectively, this study provides a comprehensive representation of cross talk between the host and bacterial pathogen, revealing insights into the Xoc-rice pathogenic dynamic and reveals novel strategies exploited by this important pathogen to cause disease.

Landslide is a slope on the soil or rock, subject to erosion of river water, groundwater activity, earthquake and artificial slope and other factors, under the action of gravity, along a plane of weakness or weak zone, whole or scattered along the slope slide down the natural phenomenon. As one of the most familiar and serious danger geological hazard. Slope has caused huge life and property losses of our country and people. So it is necessary to analyze the stable state when facing serious landslide hazards, and giving a reasonable evaluation. Taking Zhouqu Suoertou landslide as an example in this paper, on the basis of investigation and study, general situation of Suoertou landslide is introduced, then the stable state is analyzed, calculated and evaluated, the conclusion is a depend basis for later treatment.

PVA hydrogel has been used in the field of cartilage replacement in recent year. In order to improve the water-keeping ability of PVA gel and mechanical property, PVP was introduced into PVA and crosslinked by adding ammonium persulfate to form a composite gel. The crosslinkage of the gel was identified, and the effect of PVP and ammonium persulfate amount on the composite gel was studied. The crosslinkage, the degree of swelling and the compress stress of the composite gels have been tested. UV analysis was used to investigate the release of PVP from the composite gels. The dried composite gels were put into water to investigate the degree and velocity of the rehydration of different composite gels.