Transitory starch, a major photosynthetic product in the leaves of land plants, accumulates in chloroplasts during the day and is hydrolyzed to maltose and Glc at night to support respiration and metabolism. Previous studies in Arabidopsis thaliana indicated that the degradation of transitory starch only occurs in the chloroplasts. Here, we report that autophagy, a nonplastidial process, participates in leaf starch degradation. Excessive starch accumulation was observed in Nicotiana benthamiana seedlings treated with an autophagy inhibitor and in autophagy-related (ATG) gene-silenced N. benthamiana and in Arabidopsis atg mutants. Autophagic activity in the leaves responded to the dynamic starch contents during the night. Microscopy showed that a type of small starch granule-like structure (SSGL) was localized outside the chloroplast and was sequestered by autophagic bodies. Moreover, an increased number of SSGLs was observed during starch depletion, and disruption of autophagy reduced the number of vacuole-localized SSGLs. These data suggest that autophagy contributes to transitory starch degradation by sequestering SSGLs to the vacuole for their subsequent breakdown.

Autophagy is a conserved pathway for the bulk degradation of cytoplasmic components in all eukaryotes. This process plays a critical role in the adaptation of plants to drastic changing environmental stresses such as starvation, oxidative stress, drought, salt, and pathogen invasion. This paper summarizes the current knowledge about the mechanism and roles of plant autophagy in various plant stress responses.

Myocardial infarction, among other ischemic heart diseases, is the major cause of mortality and morbidity for patients who have heart diseases. Timely reperfusion of the ischemic myocardium is the most effective way to treat myocardial infarction. However, blood reperfusion to the ischemic tissues leads to an overproduction of toxic reactive oxygen species (ROS), which can further exacerbate myocardial damage on top of ischemic injury. ROS has been used as a diagnostic marker and therapeutic target for ischemia‐reperfusion (I/R) injury and as an environmental stimulus to trigger drug release. In this study, a ROS‐sensitive cross‐linked poly(vinyl alcohol) (PVA) hydrogel is synthesized to deliver basic fibroblast growth factor (bFGF) for myocardial repair. The therapeutic gel is injected into the pericardial cavity. Upon delivery, the hydrogel spread on the surface of the heart and form an epicardiac patch in situ. In a rat model of I/R injury, bFGF released from the gel could penetrate the myocardium. Such intervention protects cardiac function and reduces fibrosis in the post‐I/R heart, with enhanced angiomyogenesis. Furthermore, the safety and feasibility of minimally invasive injection and access into the pericardial cavity in both pigs and human patients are demonstrated.

Microtubules, the major components of cytoskeleton, are involved in various fundamental biological processes in plants. Recent studies in mammalian cells have revealed the importance of microtubule cytoskeleton in autophagy. However, little is known about the roles of microtubules in plant autophagy. Here, we found that ATG6 interacts with TUB8/β-tubulin 8 and colocalizes with microtubules in Nicotiana benthamiana. Disruption of microtubules by either silencing of tubulin genes or treatment with microtubule-depolymerizing agents in N. benthamiana reduces autophagosome formation during upregulation of nocturnal or oxidation-induced macroautophagy. Furthermore, a blockage of leaf starch degradation occurred in microtubule-disrupted cells and triggered a distinct ATG6-, ATG5- and ATG7-independent autophagic pathway termed starch excess-associated chloroplast autophagy (SEX chlorophagy) for clearance of dysfunctional chloroplasts. Our findings reveal that an intact microtubule network is important for efficient macroautophagy and leaf starch degradation.

Hydrogels are excellent drug delivery carriers with excellent ductility. Here, we report the design of a higher biostability of a recombinant human acidic fibroblast growth factor (rh-aFGF) carbomer hydrogel formulation. To verify the optimality of this formula, we prepared various prescriptions and tested the resulting physical properties including micromorphology, long-term stability, accelerated stability, and destructive test. Furthermore, the efficacy for promoting wound healing in full-thickness injury and scald wound diabetic rat models was explored. We found that rh-aFGF-carbomer hydrogel had good physical properties. It was stable for 24 months at 5 ± 3 °C, and for 6 months at 25 ± 3 °C. In vivo, the rh-aFGF-carbomer 940 hydrogel achieved a remarkable promotion of skin wound healing in diabetic rats with full-thickness injuries or scald wounds. Our data suggest that rh-aFGF-carbomer hydrogel may have applications for the treatment of diabetic ulcers combined with other wounds.