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Loquat (Eriobotrya japonica) is a model fruit for investigating flesh lignification during storage and response to chilling injury. However, the investigations of enzymes and coding genes and loquat fruit lignification under low-temperature storage are still limited. Here, the activity and transcript levels of up-stream enzymes of the phenylpropanoid pathway, including l-phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H), and 4-coumarate:coenzyme A ligase (4CL), were investigated. The results indicated that activity of these enzymes was positively correlated with loquat fruit lignification and suppression of these increases by heat treatment (HT) and low-temperature conditioning (LTC) significantly alleviated loquat fruit lignification. Coding genes for these enzymes were subsequently isolated based on information from an RNA-seq database and expression of Ej4CL1 was found to be the most responsive to low temperature and inhibition by HT and LTC treatment, whereas the other genes were less responsive to these treatments. Furthermore, function of Ej4CL1 was analyzed by transient overexpression in tobacco leaves, where it stimulated lignin accumulation. Ej4CL1 may be a key candidate that involved in CI-related loquat fruit lignification.

This study aimed to design a nanocarrier ophthalmic delivery system of muscone, a poorly water-soluble drug. The muscone thermoresponsive nanogels were self-assembled by reverse micelle → positive micelle method. Muscone was demonstrated to have uniform narrow particle size distribution in nanogel by the dynamic light scattering test. The developed nanocomposite hydrogel had a high muscone loading, and the rheology results showed that the phase transition temperature was 34.05°C. Thixotropy test indicated that the nanogel was able to resist the blinking of eyes because of the thixotropy recovery time, which is <5 s. Compared with muscone eye drops, muscone nanogels showed longer retention time on the corneal surface using fluorescent labeling technology and produced a 3.4-fold increase in apparent permeability coefficients (Papp). Draize testing showed that the developed nanogel caused no eye irritation. In vivo pharmacokinetic study indicated that the nanogel could significantly increase the bioavailability of muscone after administration compared with eye drops. These results indicate that self-assembled thermoresponsive nanogel prepared by reverse micelle → positive micelle method has potential for the ophthalmic delivery of poorly water-soluble drugs.

Lignin is important for plant secondary cell wall formation and participates in resistance to various biotic and abiotic stresses. Loquat undergoes lignification not only in vegetative tissues but also in flesh of postharvest fruit, which adversely affects consumer acceptance. Thus, researches on lignin biosynthesis and regulation are important to understand loquat fruit lignification. In loquat, a gene encoding an enzyme in the lignin biosynthesis pathway, Ej4CL1, was reported to be regulated by transcription factors, including EjMYB1, EjMYB2, EjMYB8, and EjAP2-1, knowledge of this process is still limited. With the aim of identifying novel transcriptional factors controlling lignin biosynthesis in loquat, the promoter of Ej4CL1 was utilized to screen a cDNA library by yeast one hybrid assay. A novel R2R3 MYB, named EjODO1, was identified. Real-time PCR analyses indicated that EjODO1 is highly expressed in lignified stems and roots. During fruit development, expression of EjODO1 decreased along with the reduction of lignin content and became undetectable in mature ripe fruit. Thus, EjODO1 is likely to be involved in lignification of vegetative organs and early fruit development but not in mature fruit or postharvest lignification. Dual-luciferase assay indicated that EjODO1 could trans-activate promoters of lignin biosynthesis genes, such as EjPAL1, Ej4CL1, and Ej4CL5 and transient overexpression of EjODO1 triggered lignin biosynthesis. These results indicate a role for EjODO1 in regulating lignin biosynthesis in loquat which is different from the previously characterized transcription factors.

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In this study, pH-sensitive poly(2-ethyl-2-oxazoline)-poly(lactic acid)-poly(βamino ester) (PEOz-PLA-PBAE) triblock copolymers were synthesized and were conjugated with an antimalaria drug artesunate (ART), for inhibition of a colon cancer xenograft model. Methods: The as-prepared polymer prodrugs are tended to self-assemble into polymeric micelles in aqueous milieu, with PEOz segment as hydrophilic shell and PLA-PBAE segment as hydrophobic core. Results: The pH sensitivity of the as-prepared copolymers was confirmed by acid-base titration with pKb values around 6.5. The drug-conjugated polymer micelles showed high stability for at least 96 h in PBS and 37°C, respectively. The as-prepared copolymer prodrugs showed high drug loading content, with 9.57%±1.24% of drug loading for PEOz-PLA-PBAE-ART4. The conjugated ART could be released in a sustained and pH-dependent manner, with 92% of released drug at pH 6.0 and 57% of drug released at pH 7.4, respectively. In addition, in vitro experiments showed higher inhibitory effect of the prodrugs on rodent CT-26 cells than that of free ART. Animal studies also demonstrated the enhanced inhibitory efficacy of PEOz-PLA-PBAE-ART2 micelles on the growth of rodent xenograft tumor. Conclusion: The pH-responsive artesunate polymer prodrugs are promising candidates for colon cancer adjuvant therapy.

In this study, ginger juice powders (GJPs) were obtained from ginger juice using vacuum drying, spray drying, vacuum microwave drying (VMD), and freeze‐drying (FD). The physical properties (water content, dissolving time, and color), chemical compositions (total volatiles, gingerols and shogaol, total phenolic content [TPC]), antioxidant activity, and aerobic bacteria content of the GJPs/redissolved ginger juice were determined and the effect of the drying processes on ginger juice was evaluated. The result showed that FD was optimal at retaining the color, gingerols, shogaol, and total volatiles of the ginger juice, while both VMD and FD could retain a high yield of TPC and the antioxidant activity of the ginger juice. It was also found that all the drying methods were effective in reducing the total aerobic bacteria of the ginger juice. This study proved that the four drying methods had very different effects on the quality of the ginger juice, among which FD was optimal for processing ginger juice. Practical applications In this study, four processing methods of ginger juice were compared by investigating the physical properties (water content, dissolving time, and color), chemical compositions (total volatiles, gingerols and shogaol, total phenolic content), antioxidant activity, and aerobic bacteria content of the different ginger juice powers prepared. The results will provide new reference for processing ginger.

The dynamic model parameter identification is important for unmanned aerial vehicle modeling and control. The unmanned aerial vehicle model parameters are usually identified through wind tunnel experiments, which are complex. In this paper, a model parameter identification method is proposed using the flight data for quadrotors. The parameters of the thrust, drag force, torque, rolling moment and pitching moment are estimated through Kalman filter. Global positioning system and inertial sensors are used as measurements. The observabilities of the model parameters and their degrees of observability are analyzed. Flight experiments are carried out to verify the proposed method. It is shown that the model parameters estimated by the proposed method have good accuracies, demonstrating the validity of the proposed method.