Changes in Diversity and Composition of Rhizosphere Bacterial and Fungal Community between Resistant and Susceptible Pakchoi under Plasmodiophora brassicae.

Plasmodiophora brassicae (P. brassicae) is a soil-born pathogen worldwide and can infect most cruciferous plants, which causes great yield decline and economic losses. It is not well known how microbial diversity and community composition change during P. brassicae infecting plant roots. Here, we employed a resistant and a susceptible pakchoi cultivar with and without inoculation with P. brassicae to analyze bacterial and fungal diversity using 16S rRNA V3-V4 and ITS_V1 regions, respectively. 16S rRNA V3-V4 and ITS_V1 regions were amplified and sequenced separately. Results revealed that both fungal and bacterial diversity increased, and composition was changed in the rhizosphere soil of the susceptible pakchoi compared with the resistant cultivar. In the four groups of R_mock, S_mock, R_10d, and S_10d, the most relatively abundant bacterium and fungus was Proteobacteria, accounting for 61.92%, 58.17%, 48.64%, and 50.00%, respectively, and Ascomycota, accounting for 75.11%, 63.69%, 72.10%, and 90.31%, respectively. A total of 9488 and 11,914 bacteria were observed uniquely in the rhizosphere soil of resistant and susceptible pakchoi, respectively, while only 80 and 103 fungi were observed uniquely in the correlated soil. LefSe analysis showed that 107 and 49 differentially abundant taxa were observed in bacteria and fungi. Overall, we concluded that different pakchoi cultivars affect microbial diversity and community composition, and microorganisms prefer to gather around the rhizosphere of susceptible pakchoi. These findings provide a new insight into plant-microorganism interactions.

Process Optimization of Dual-Liquid Casting and Interfacial Strength-Toughness of the Produced LAS/HCCI Bimetal.

The pouring time interval is the decisive factor of dual-liquid casting for bimetallic productions. Traditionally, the pouring time interval is fully determined by the operator's experience and on-site observation. Thus, the quality of bimetallic castings is unstable. In this work, the pouring time interval of dual-liquid casting for producing low alloy steel/high chromium cast iron (LAS/HCCI) bimetallic hammerheads is optimized via theoretical simulation and experimental verification. The relevancies of interfacial width and bonding strength to pouring time interval are, respectively, established. The results of bonding stress and interfacial microstructure indicate that 40 s is the optimum pouring time interval. The effects of interfacial protective agent on interfacial strength-toughness are also investigated. The addition of the interfacial protective agent yields an increase of 41.5% in interfacial bonding strength and 15.6% in toughness. The optimum dual-liquid casting process is used to produce LAS/HCCI bimetallic hammerheads. Samples cut from these hammerheads show excellent strength-toughness (1188 Mpa for bonding strength and 17 J/cm2 for toughness). The findings could be a reference for dual-liquid casting technology. They are also helpful for understanding the formation theory of the bimetal interface.

Edaravone protects against oxygen-glucose-serum deprivation/restoration-induced apoptosis in spinal cord astrocytes by inhibiting integrated stress response.

We previously found that oxygen-glucose-serum deprivation/restoration (OGSD/R) induces apoptosis of spinal cord astrocytes, possibly via caspase-12 and the integrated stress response, which involves protein kinase R-like endoplasmic reticulum kinase (PERK), eukaryotic initiation factor 2-alpha (eIF2α) and activating transcription factor 4 (ATF4). We hypothesized that edaravone, a low molecular weight, lipophilic free radical scavenger, would reduce OGSD/R-induced apoptosis of spinal cord astrocytes. To test this, we established primary cultures of rat astrocytes, and exposed them to 8 hours/6 hours of OGSD/R with or without edaravone (0.1, 1, 10, 100 µM) treatment. We found that 100 µM of edaravone significantly suppressed astrocyte apoptosis and inhibited the release of reactive oxygen species. It also inhibited the activation of caspase-12 and caspase-3, and reduced the expression of homologous CCAAT/enhancer binding protein, phosphorylated (p)-PERK, p-eIF2α, and ATF4. These results point to a new use of an established drug in the prevention of OGSD/R-mediated spinal cord astrocyte apoptosis via the integrated stress response.