Photodynamic therapy (PDT), using a combination of chemical photosensitizers (PS) and light, has been successfully applied as a noninvasive therapeutic procedure to treat tumors by inducing apoptosis or necrosis of cancer cells. However, most current clinically used PS have suffered from the instability in physiological conditions which lead to low photodynamic therapy efficacy. Herein, a highly biocompatible poly(dopamine) (PDA) nanoparticle conjugated with Chlorin e6 (referenced as the PDA-Ce6 nanosphere) was designed as a nanotherapeutic agent to achieve simultaneous photodynamic/photothermal therapy (PDT/PTT). Compared to the free Ce6, the PDA-Ce6 nanosphere exhibited significantly higher PDT efficacy against tumor cells, because of the enhanced cellular uptake and subsequently greater reactive oxygen species (ROS) production upon laser irradiation at 670 nm. Meanwhile, the PDA-Ce6 nanosphere could be also used as a photoabsorbing agent for PTT, because of the excellent photothermal conversion ability of PDA nanoparticle under laser irradiation at 808 nm. Moreover, our prepared nanosphere had extremely low dark toxicity, while excellent phototoxicity under the combination laser irradiation of 670 and 808 nm, both in vitro and in vivo, compared to any single laser irradiation alone. Therefore, our prepared PDA-Ce6 nanosphere could be applied as a very promising dual-modal phototherapeutic agent for enhanced cancer therapy in future clinical applications.

In plants, auxin functions as a master controller of development, pattern formation, morphogenesis, and tropic responses. A sophisticated transport system has evolved to allow the establishment of precise spatiotemporal auxin gradients that regulate specific developmental programs. A critical unresolved question relates to how these gradients can be maintained in the presence of open plasmodesmata that allow for symplasmic exchange of essential nutrients and signaling macromolecules. Here we addressed this conundrum using genetic, physiological, and cell biological approaches and identified the operation of an auxin-GSL8 feedback circuit that regulates the level of plasmodesmal-localized callose in order to locally downregulate symplasmic permeability during hypocotyl tropic response. This system likely involves a plasmodesmal switch that would prevent the dissipation of a forming gradient by auxin diffusion through the symplasm. This regulatory system may represent a mechanism by which auxin could also regulate symplasmic delivery of a wide range of signaling agents.

Cytokinesis is the division of the cytoplasm and its separation into two daughter cells. Cell plate growth and cytokinesis appear to require callose, but direct functional evidence is still lacking. To determine the role of callose and its synthesis during cytokinesis, we identified and characterized mutants in many members of the GLUCAN SYNTHASE-LIKE (GSL; or CALLOSE SYNTHASE) gene family in Arabidopsis (Arabidopsis thaliana). Most gsl mutants (gsl1-gsl7, gsl9, gsl11, and gsl12) exhibited roughly normal seedling growth and development. However, mutations in GSL8, which were previously reported to be gametophytic lethal, were found to produce seedlings with pleiotropic defects during embryogenesis and early vegetative growth. We found cell wall stubs, two nuclei in one cell, and other defects in cell division in homozygous gsl8 insertional alleles. In addition, gsl8 mutants and inducible RNA interference lines of GSL8 showed reduced callose deposition at cell plates and/or new cell walls. Together, these data show that the GSL8 gene encodes a putative callose synthase required for cytokinesis and seedling maturation. In addition, gsl8 mutants disrupt cellular and tissue-level patterning, as shown by the presence of clusters of stomata in direct contact and by islands of excessive cell proliferation in the developing epidermis. Thus, GSL8 is required for patterning as well as cytokinesis during Arabidopsis development.

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Multifunctional theranostic nanoparticles represent an emerging agent with the potential to offer extremely sensitive diagnosis and targeted cancer therapy. Herein, we report the synthesis and characterization of a multifunctional theranostic agent (referred to as LA-LAPNHs) for targeted magnetic resonance imaging/computed X-ray tomography (MRI/CT) dual-mode imaging and photothermal therapy of hepatocellular carcinoma. The LA-LAPNHs were characterized as having a core-shell structure with the gold nanoparticles (AuNPs)@polydopamine (PDA) as the inner core, the indocyanine green (ICG), which is electrostatically absorbed onto the surface of PDA, as the photothermal therapeutic agent, and the lipids modified with gadolinium-1,4,7,10-tetraacetic acid and lactobionic acid (LA), which is self-assembled on the outer surface as the shell. The LA-LAPNHs could be selectively internalized into the hepatocellular cell line (HepG2 cells) but not into HeLa cells due to the specific recognition ability of LA to asialoglycoprotein receptor. Additionally, the dual-mode imaging ability of the LA-LAPNH aqueous solution was confirmed by enhanced MR and CT imaging showing a shorter T1 relaxation time and a higher Hounsfield unit value, respectively. In addition, the LA-LAPNHs showed significant photothermal cytotoxicity against liver cancer cells with near-infrared irradiation due to their strong absorbance in the region between 700 and 850 nm. In summary, this study demonstrates that LA-LAPNHs may be a promising candidate for targeted MR/CT dual-mode imaging and photothermal therapy of hepatocellular carcinoma.

Pathogen-host interaction is a complicated process; pathogens mainly infect host plants to acquire nutrients, especially sugars. Rhizoctonia solani, the causative agent of sheath blight disease, is a major pathogen of rice. However, it is not known how this pathogen obtains sugar from rice plants. In this study, we found that the rice sugar transporter OsSWEET11 is involved in the pathogenesis of sheath blight disease. Quantitative real-time polymerase chain reaction (qRT-PCR) and β-d-glucuronidase expression analyses showed that R. solani infection significantly enhanced OsSWEET11 expression in leaves amongst the clade III SWEET members. The analyses of transgenic plants revealed that Ossweet11 mutants were less susceptible, whereas plants overexpressing OsSWEET11 were more susceptible, to sheath blight compared with wild-type controls, but the yield of OsSWEET11 mutants and overexpressors was reduced. SWEETs become active on oligomerization. Split-ubiquitin yeast two-hybrid, bimolecular fluorescence complementation and co-immunoprecipitation assays showed that mutated OsSWEET11 interacted with normal OsSWEET11. In addition, expression of conserved residue mutated AtSWEET1 inhibited normal AtSWEET1 activity. To analyse whether inhibition of OsSWEET11 function in mesophyll cells is related to defence against this disease, mutated OsSWEET11 was expressed under the control of the Rubisco promoter, which is specific for green tissues. The resistance of transgenic plants to sheath blight disease, but not other disease, was improved, whereas yield production was not obviously affected. Overall, these results suggest that R. solani might acquire sugar from rice leaves by the activation of OsSWEET11 expression. The plants can be protected from infection by manipulation of the expression of OsSWEET11 without affecting the crop yield.

Plant cells utilize mobile transcription factors to transmit intercellular signals when they perceive environmental stimuli or initiate developmental programmes. Studies on these novel cell-to-cell signals have accumulated multiple pieces of evidence showing that non-cell-autonomous transcription factors play pivotal roles in most processes related to the formation and development of plant organs. Recent studies have explored the evolution of mobile transcription factors and proposed mechanisms for their trafficking through plasmodesmata, where a selective system exists to facilitate this process. Mobile transcription factors contribute to the diversity of the intercellular signalling network, which is also established by peptides, hormones, and RNAs. Crosstalk between mobile transcription factors and other intercellular molecules leads to the development of complex biological signalling networks in plants. The regulation of plasmodesmata appears to have been another major step in controlling the intercellular trafficking of transcription factors based on studies of many plasmodesmal components. Furthermore, diverse omics approaches are being successfully applied to explore a large number of candidate transcription factors as mobile signals in plants. Here, we review these fascinating discoveries to integrate current knowledge of non-cell-autonomous transcription factors.