Combined Transcriptomic and Metabolomic Analysis Reveals the Role of Phenylpropanoid Biosynthesis Pathway in the Salt Tolerance Process of Sophora alopecuroides.

Salt stress is the main abiotic stress that limits crop yield and agricultural development. Therefore, it is imperative to study the effects of salt stress on plants and the mechanisms through which plants respond to salt stress. In this study, we used transcriptomics and metabolomics to explore the effects of salt stress on Sophora alopecuroides. We found that salt stress incurred significant gene expression and metabolite changes at 0, 4, 24, 48, and 72 h. The integrated transcriptomic and metabolomic analysis revealed that the differentially expressed genes (DEGs) and differential metabolites (DMs) obtained in the phenylpropanoid biosynthesis pathway were significantly correlated under salt stress. Of these, 28 DEGs and seven DMs were involved in lignin synthesis and 23 DEGs and seven DMs were involved in flavonoid synthesis. Under salt stress, the expression of genes and metabolites related to lignin and flavonoid synthesis changed significantly. Lignin and flavonoids may participate in the removal of reactive oxygen species (ROS) in the root tissue of S. alopecuroides and reduced the damage caused under salt stress. Our research provides new ideas and genetic resources to study the mechanism of plant responses to salt stress and further improve the salt tolerance of plants.

Development of anti-bacterial adhesion and antibacterial sulfobetaines modified chitosan/polyvinyl alcohol composite films as packaging materials.

Chitosan exhibits a wide source, non-toxic and biodegradable, and is the optimal functional raw material for preparing food packaging materials. However, the pure chitosan film has some disadvantages such as limited antibacterial activity and weak mechanical properties. In this study, sulfobetaines modified chitosan (CS-SBMA) was synthesized by grafting copolymerized betaine methacrylate sulfonate onto the chain of chitosan to improve the anti-bacterial adhesion and antibacterial properties of chitosan, aiming to develop antibacterial and anti-bacterial adhesion films based on CS-SBMA and polyvinyl alcohol (PVA) by the casting method. The structure of CS-SBMA was characterized by 1H NMR and FTIR. The appropriate proportion of CS-SBMA/PVA was determined to be 1/1 and 1/2, by characterizing the composite films with FTIR, XRD, SEM, mechanical, optical, and water resistance behaviors. In addition, CS-SBMA/PVA films showed excellent antibacterial, anti-bacterial adhesion and biofilm control function. The colonies number of E. coli and S. aureus on the surface of CS-SBMA/PVA 1/1 film decreased 94.15 % and 94.27 %, respectively, and 92.93 % of S. aureus and 94.87 % of E. coli colonies were inactivated within 60 min contact. These results indicate that CS-SBMA/PVA film exhibits potential antibacterial and anti-bacterial adhesion properties, which is suitable for food packaging materials.

Cellulose Acetate Nanofibrous Membranes for Antibacterial Applications.

BACKGROUNDS: N-halamine antibacterial materials have been extensively explored over the past few decades due to their fast inactivation of a broad spectrum of bacterial and rechargeability. Electrospun nanofibers loaded with N-halamines have gained great attention because of their enhanced antibacterial capability induced by the larger specific surface area. The patents on electrospun nanofibers (US20080679694), (CN2015207182871) helped in the method for the preparation of nanofibers. METHODS: In this study, a novel N-halamine precursor, 3-(3'-Chloro-propyl)-5,5-dimethylimidazolidine- 2,4-dione(CPDMH), was synthesized. Antimicrobial electrospun Cellulose Acetate (CA) nanofibers were fabricated through impregnating CPDMH as an antimicrobial agent into CA fibers by the bubble electrospinning. The surface morphologies of CA/CPDMH nanofibrous membranes were characterized by Scanning Electron Microscope (SEM). RESULTS: The chlorinated fibrous membranes (CA/CPDMH-Cl) exhibited effective antimicrobial activity against 100% of S. aureus and E. coli O157:H7 within 1 min and 5 min, respectively. The CA/CPDMH-Cl nanofibrous membranes showed good storage stability under the dark and excellent durability towards UVA light exposure. Meanwhile, the release of active chlorine from the chlorinated nanofibrous membranes was stable and safe. Besides, the addition of CPDMH could improve the mechanical property, and chlorination did not obviously affect the strength and elongation of the nanofibrous membranes. CONCLUSION: CPDMH could endow the electrospun CA nanofibers with powerful, durable and regenerable antimicrobial properties. It will provide a continuous and effective method for health-care relative industrial application.

Cotton fabric with plasma pretreatment and ZnO/Carboxymethyl chitosan composite finishing for durable UV resistance and antibacterial property.

ZnO/carboxymethyl chitosan (ZnO/CMCS) composite was prepared and confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Ultraviolet-visible (UV-vis) spectroscopy, Scanning electron microscope (SEM), Transmission electron microscope (TEM). The combination of plasma pretreatment and ZnO/CMCS composite finishing was applied to provide durable UV resistance and antibacterial activity for cotton fabric. Cotton fabric was pretreated by cold oxygen plasma and the ZnO/CMCS composite finishing was carried out by pad-dry-cure. Cotton fabric was characterized by SEM, FTIR, UV resistance, antibacterial activity and Thermogravimetry (TG). SEM and FTIR analysis demonstrated the presence of ZnO/CMCS composite on cotton fabric and the increasing loading efficiency of ZnO/CMCS composite owing to plasma treatment. UV resistance and antibacterial activity of the finished cotton fabric were greatly improved, which increased with the increasing concentration of ZnO/CMCS composite. TG analysis indicated that the combined finishing of cotton fabric with plasma pretreatment and ZnO/CMCS composite could improve its thermal property. The finished cotton fabric exhibited an excellent laundering durability in UV resistance and antibacterial activity.

Interfacial reaction of intermetallic compounds of ultrasonic-assisted brazed joints between dissimilar alloys of Ti6Al4V and Al4Cu1Mg.

Ultrasonic-assisted brazing of Al4Cu1Mg and Ti6Al4V using Zn-based filler metal (without and with Si) has been investigated. Before brazing, the Ti6Al4V samples were pre-treated by hot-dip aluminizing and ultrasonic dipping in a molten filler metal bath in order to control the formation of intermetallic compounds between the Ti6Al4V samples and the filler metal. The results show that the TiAl(3) phase was formed in the interface between the Ti6Al4V substrate and the aluminized coating. For the Zn-based filler metal without Si, the Ti6Al4V interfacial area of the brazed joint did not change under the effect of the ultrasonic wave, and only consisted of the TiAl(3) phase. For the Zn-based filler metal with Si, the TiAl(3) phase disappeared and a Ti(7)Al(5)Si(12) phase was formed at the interfacial area of the brazed joints under the effect of the ultrasonic wave. Due to the TiAl(3) phase completely changing to a Ti(7)Al(5)Si(12) phase, the morphology of the intermetallic compounds changed from a block-like shape into a lamellar-like structure. The highest shear strength of 138MPa was obtained from the brazed joint free of the block-like TiAl(3) phase.