A novel strategy and characteristics of PVA/citric acid cross-linked hydrophilic elastic sponge of cellulose based on medicinal herb residue.

A new ultra-hydrophilic elastic sponge composite has been proposed. Medicinal herbs, commonly used in herbal medicine and subsequently discarded, are rich in natural polymer substances, making them promising candidates for various material industries. TEMPO-oxidized cellulose was extracted from medicinal herb residue, and the physicochemical properties of an ultra-hydrophilic elastic sponge, prepared through a PVA and CA impregnate cross-linking process, were investigated. The fabricated composite sponge exhibited an increase in compressive stress-strain proportional to the PVA cross-linking concentration, and its water retention capability was assessed through retention tests. Swelling tests for various solvents were conducted to evaluate the potential use of the sponge in diverse industries, revealing the highest swelling ratio in water. Pressure distribution measurements using prescale film indicated that the sponge's shock absorption capacity was enhanced by PVA cross-linking, leading to improved pressure dispersion.

Mitigation of benzoic acid-driven autotoxicity in waste nutrient solution using O3 and O3/H2O2 treatments: Seed germination and root growth of Lactuca sativa L.

Benzoic acid (BA), a secondary metabolite released through root exudates, is considered to be the most common inhibitor that leads to plant autotoxicity, even at low concentrations in closed hydroponic systems. In this study, to mitigate BA-driven autotoxicity, the effects of O3 and O3/H2O2 oxidation treatment (O3 concentration: 1, 2, 4, 8 mg L-1, H2O2 concentration: 4, 8 mg L-1) on waste nutrient solution (WNS) were investigated in terms of BA degradation, the rate of germination inhibition (GI), and the rate of root growth inhibition (RI). In the case of O3 treatment, the BA degradation rate improved up to 14.1% as the O3 concentration increased, while alleviation of GI was insignificant (94.6-100%), confirming that a single O3 treatment was unsuitable for mitigating autotoxicity. On the other hand, O3/H2O2 treatment increased BA degradation by up to 24.8%, thereby significantly reducing GI (up to 7.69%) and RI (up to 0.88%). Both the highest BA mineralization rate and phytotoxicity mitigation was observed at BA125 (4-4) (BA mineralization: 16.7%, GI: 12.82%, RI: 11.69%) and BA125 (1-8) (BA mineralization: 17.7%, GI: 7.69%, RI: 0.88%) at each H2O2 concentration. In addition, the operating costs were evaluated by a chemical and electricity cost analysis at the different treatments. As a result, the operating costs of BA125 (4-4) and BA125 (1-8) were calculated to be 0.40 and 0.42 $ L-1 mg-1 of mineralized BA, respectively. After consideration of the mineralization rate, autotoxicity mitigation, and operating cost, BA125 (1-8) was suggested for the optimal treatment condition and our findings would contribute to the alleviation of BA-driven autotoxicity.

An efficient method for organic acetylation and use of DL-phosphinothricin as a negative selection agent in argE transgenic rice.

We present an efficient method for the production of N-acetyl-L-phosphinothricin (N-AcPt) from commercial DL-phosphinothricin (DL-PPT) by organic acetylation for use as a negative selection agent (NSA) that induces cell death in argE transgenic rice. DL-PPT was efficiently converted into N-AcPt with tetrahydrofuran (THF) and acetic anhydride (Ac2O). Chemical changes were confirmed using NMR and ATR-FTIR analyses. DL-PPT was toxic but N-AcPt did not show cytotoxic effects on leaf discs or seed germination of wild-type rice. Conversely, in argE-hpt transgenic rice, non-toxic N-AcPt showed the negative selection (NS) effect by inducing cell destruction in leaf discs and restricting seed germination. For inducing NS, ≥0.1 mg ml(-1) and ≥0.5 mg ml(-1) of N-AcPt were effective in leaf and seed assays, respectively. Further, the NS effect occurred faster in the leaf assay compared with the seed germination assay, again indicating the leaf assay was a more sensitive indicator of N-AcPt as an NSA to argE transgenic rice than the seed germination assay. This negative selection approach could be useful for the development of selectable marker free transgenic plants in the economically important monocot species and its commercialization for multiple gene transformation.