Dual Organism Transcriptomics of Airway Epithelial Cells Interacting with Conidia of Aspergillus fumigatus

Background Given the complex nature of the responses that can occur in host-pathogen interactions, dual transcriptomics offers a powerful method of elucidating these interactions during infection. The gene expression patterns of Aspergillus fumigatus conidia or host cells have been reported in a number of previous studies, but each focused on only one of the interacting organisms. In the present study, we profiled simultaneously the transcriptional response of both A. fumigatus and human airway epithelial cells (AECs). Methodology 16HBE14o- transformed bronchial epithelial cells were incubated with A. fumigatus conidia at 37°C for 6 hours, followed by genome-wide transcriptome analysis using human and fungal microarrays. Differentially expressed gene lists were generated from the microarrays, from which biologically relevant themes were identified. Human and fungal candidate genes were selected for validation, using RT-qPCR, in both 16HBE14o- cells and primary AECs co-cultured with conidia. Principal Findings We report that ontologies related to the innate immune response are activated by co-incubation with A. fumigatus condia, and interleukin-6 (IL-6) was confirmed to be up-regulated in primary AECs via RT-qPCR. Concomitantly, A. fumigatus was found to up-regulate fungal pathways involved in iron acquisition, vacuolar acidification, and formate dehydrogenase activity

Microstructure evolution and fracture mechanism of a TiAl-Nb alloy during high-temperature tensile testing

A TiAl-Nb alloy was prepared by casting, and its tensile properties and microstructure evolution at different temperatures were investigated. The results show that the brittle-ductile transition temperature (BDTT) of the alloy is 880-920 degrees C. At low temperatures, deformation mainly occurs in the gamma lamellae and coarsening gamma phase between the lamellar colonies. As the temperature increase in the transitory stage, a small number of dislocations may pass through the interface from the coarsening gamma phase into the gamma lamellae. During the brittle stage, the dislocation and dislocation array bow out from the phase interface, and twins are emitted from the phase interface, which may contribute to the accommodation of stress concentration. During the ductile stage, the gamma lamellae coarsen due to the thinner and smaller alpha 2 lamellae dissolving and phase boundary transfer. The dislocations interact with the dislocation walls to form subboundaries in the gamma lamellae and transform into equiaxed crystals by dynamic recrystallization (DRX), which increases the plasticity of the alloy. With the transition from the brittle model to the ductile model, the fracture mode of the alloy changes from the mixed fracture mode of transgranular fracture and translaminar fracture to intergranular fracture

Deformation and damage behaviors of as-cast TiAl-Nb alloy during creep

By means of creep properties measurement and microstructure observation, the deformation and damage behavior of an as-cast TiAl-Nb alloy during creep at temperature near 750 °C were investigated. The results showed that the microstructure of the alloy consisted of lamellar γ/α2 phase, and the boundaries consisted of γ phase located in between lamellar γ/α2 phases with different orientations. In the latter stage of creep, the dislocation networks appeared in the interfaces of lamellar γ/α2 phases due to the coarsening of them, which made the coherent interface transforming into the semi-coherent one for reducing its adhesive strength. The deformation mechanism of the alloy during creep was twinning and dislocations slipping within lamellar γ/α2 phases. In the later period of creep, significant amount of dislocations plied up in the interfaces of lamellar γ/α2 phases, which may cause the stress concentration to promote the initiation and propagation of the cracks along the lamellar γ/α2 interfaces perpendicular to the stress axis. Wherein, some cracks on the various cross-sections were connected by tearing edge along the direction of maximum shear stress, up to the creep fracture, which is considered to be the damage and fracture mechanism of alloy during creep at 750 °C. Keywords: TiAl-Nb alloy, Creep, Dislocation network, Deformation mechanism, Fracture mechanis

Rapid Detection of A282S Mutation in the <i>RDL1</i> Gene of Rice Stem Borer via the Mutation-Specific LAMP Technique

Rice stem borer Chilo suppressalis (Walker) is one of the most serious pests on rice and is distributed worldwide. With the long-term and continuous usage of insecticides, C. suppressalis has developed high levels of resistance to various kinds of insecticides, including phenylpyrazole insecticides. As is well known, the resistance of C. suppressalis to phenylpyrazole insecticides is determined by the A282S mutation of the GABA receptor RDL subunit. In order to efficiently detect the resistance of C. suppressalis, a rapid and sensitive loop-mediated isothermal amplification (LAMP) technique was established and optimized in this study. The optimal concentration of components was Bst DNA polymerase (0.24 U/μL), dNTP (0.8 mM), Mg2+ (4 mM), betaine (0.6 M), forward inner primer and backward inner primer (1.6 μM), F3 and B3 (0.4 μM), and hydroxyl naphthol blue (150 mM), respectively, and the optimal reaction condition was 63 °C for 60 min, which could reduce the cost and time of detection. In addition, the accuracy of the optimized LAMP reaction system and parameters was verified in the field strains of C. suppressalis from different regions, including Jiangsu, Jiangxi, and Hu’nan provinces. The mutation (A2’S) was successfully detected in the field strains. As far as we know, this is the first report of the LAMP technique applied in the resistance monitoring of C. suppressalis to phenylpyrazole insecticides. According to our results, the optimized LAMP reaction system is feasible and easy to operate and to efficiently detect resistance-related mutation in a short time, as directly judged by the naked eye. Our results provide a new tool for detection of resistance of C. suppressalis, which is a very useful tool for comprehensive management of C. suppressalis

Doping dependence of the second magnetization peak, critical current density and pinning mechanism in BaFe2−xNixAs2 Pnictide superconductors

A series of high quality BaFe$_{2-x}$Ni$_x$As$_2$ pnictide superconductors were studied using magnetic relaxation and isothermal magnetic measurements in order to study the second magnetization peak (SMP) and critical current behaviour in Ni-doped 122 family. The temperature dependence of the magnetic relaxation rate suggests a pinning crossover, whereas, it's magnetic field dependence hints a vortex-lattice structural phase-transition. The activation energy ($U$) estimated using the magnetic relaxation data was analyzed in detail for slightly-underdoped, slightly-overdoped and an overdoped samples, using Maley's method and collective creep theory. Our results confirm that the SMP in these samples is due to the collective (elastic) to plastic creep crossover as has been observed for the other members of 122-family. In addition, we also investigated the doping dependence of the critical current density ($J_c$) and the vortex-pinning behaviour in these compounds. The observed $J_c$ is higher than the threshold limit (10$^5$ A/cm$^2$) considered for the technological potential and even greater than 1 MA/cm$^2$ for slightly underdoped Ni-content, x = 0.092 sample. The pinning characteristics were analyzed in terms of the models developed by Dew-Hughes and Griessen $et$ $al$, which suggest the dominant role of $\delta l$-type pinning