Artificial photosynthetic cells with biotic-abiotic hybrid energy modules for customized CO2 conversion.

Programmable artificial photosynthetic cell is the ultimate goal for mimicking natural photosynthesis, offering tunable product selectivity via reductase selection toward device integration. However, this concept is limited by the capacity of regenerating the multiple cofactors that hold the key to various reductases. Here, we report the design of artificial photosynthetic cells using biotic-abiotic thylakoid-CdTe as hybrid energy modules. The rational integration of thylakoid with CdTe quantum dots substantially enhances the regeneration of bioactive NADPH, NADH and ATP cofactors without external supplements by promoting proton-coupled electron transfer. Particularly, this approach turns thylakoid highly active for NADH regeneration, providing a more versatile platform for programming artificial photosynthetic cells. Such artificial photosynthetic cells can be programmed by coupling with diverse reductases, such as formate dehydrogenase and remodeled nitrogenase for highly selective production of formate or methane, respectively. This work opens an avenue for customizing artificial photosynthetic cells toward multifarious demands for CO2 conversion.

Analysis of DNA methylation in potato tuber in response to light exposure during storage.

Exposure to light induces tuber greening and the accumulation of the toxic alkaloid Solanine in potato (Solanum tuberosum L) during storage greatly reduce tuber value. While the mechanism of this greening process remains unclear, it is well understood that DNA methylation plays an important role in regulating gene expression in response to environmental conditions. In this study, methylation-sensitive amplified polymorphism was used to assess the effect of light exposure on DNA methylation during storage of potato tubers. Light-induced genome-wide DNA demethylation and the rate of DNA methylation decreased with long storage times. Following, the sequencing of 14 differentially amplified fragments and analysis using the Basic Local Alignment Search Tool, eight genomic sequences and six annotated fragment sequences were identified. The latter included ADP glucose pyrophosphorylase 1/2, chlorophyllide a oxygenase 1 (CAO1), receptor-like protein kinase HAIKU2, and repressor of GA4, all of which are involved in starch biosynthesis, chlorophyll synthesis, endosperm development, and gibberellic acid signaling, respectively. Demethylation was observed in the CpG island (-273 to -166 bp) of the CAO1 promoter in response to light, which further confirmed that the variations in genome methylation are dependent upon the light exposure and suggests a direct role for DNA methylation. Our results provide an epigenetic perspective for further exploring the mechanism of light-induced tuber greening.

UHPLC-MS-based metabolomic approach for the quality evaluation of Pinellia ternata tubers grown in shaded environments.

Pinellia ternata is a native herb in China, and its tuber is widely-used in traditional Chinese medicines. It has been identified that the shading treatment promotes tuber production during cultivation. However, the tuber quality in shaded environments is unknown, which limits the scientific cultivation of P. ternata. In this study, a metabolomics approach based on UHPLC-MS was applied to assess the metabolic components of P. ternata in response to shading. Diverse metabolites were profiled using the metabolomics approach. Then, datasets of P. ternata cultivated in natural light (control) and shaded environments were subjected to multivariate analyses. Two P. ternata tuber products were well separated by the PCA. In total, four P. ternata alkaloids with contents that were not altered by the shaded environment were detected. Metabolomic analyses further identified several organic acids [mevalonic acid, 12,13-dihydroxy-9Z-octadecenoic acid (12, 13-DiHOME), urocanic acid, and γ-aminobutyric acid] that were largely enriched in the shaded environment, which likely contributed to tuber quality and growth. This study determined that shading probably improves the quality of P. ternata tubers and laid a foundation for exploring the regulatory mechanism of the shade response in P. ternata.

[Analysis of shading on DNA methylation by MSAP in Pinellia ternata].

Pinellia ternata is a medicinal herb of Araceae, and its tubers are used as medicines. It is a common Chinese herbal medicine in China and has a large market demand. When exposing to strong light intensity and high temperature during the growth process, P. ternata withers in a phenomenon known as "sprout tumble", which largely limits tuber production. Shade can effectively delay sprout tumble formation and increase its yield, however the relevant regulation mechanism is unclear. DNA methylation, as a self-modifying response to environmental changes, is often involved in the regulation of plant growth and development. In this study, P. ternata grown under natural light and 90% shading were selected as the control group and the experimental group for genomic DNA methylation analysis by using methylate sensitive amplification polymorphism(MSAP). The results showed that a total of 617 loci were detected with 20 pairs of primers, of which 311 were in the natural light group and 306 in the shading group. The methylation sites in the light and shading groups accounted for 58.2% and 71.57%, respectively, and the methylation ratios in the methylation sites were 27.65% and 29.41%, respectively, indicating that shading significantly induced the genome DNA methylation of P. ternata. Compared to the natural light group, shading promoted 32.51% of the genes methylation, while inducing 16.25% gene demethylation. This study reveals the DNA methylation variation of P. ternata under shading conditions, which lays a preliminary theoretical foundation for further analysis of the mechanism of shading regulation of P. ternata growth from epigenetic level.

[Variation analysis of genomic methylation induced by high temperature stress in Pinellia ternata].

Pinellia ternata belongs to the Araceae family and is a medicinal herb. The tuber is the medicinal organ with antitussive, antiemetic and anti-tumor activities. It is easy to encounter high temperature environment during the growth periods, leading to decrease of tuber production. At present, the mechanism of response to high temperature stress in P. ternata is still unknown. DNA methylation plays a vital role in plant protection against adversity stress as a way of epigenetic regulation. In this study, P. ternata was used as material for treatment of high temperature stress at 0 h, 6 h and 80 h, and methylation sensitive amplification polymorphism(MSAP) analysis was conducted on the changes of DNA methylation in its genome. The results showed that 20 pairs of MSAP primers were selected from 100 MSAP primers with multiple clear and uniform bands, and 353, 355 and 342 loci were amplified from materials of P. ternata treated in the high temperature stress 0 h, 6 h and 80 h, respectively. Cytosine methylation levels of CCGG context in the above materials were characterized as 60.91%, 44.79% and 44.74%, respectively. And the full methylation ratios were 16.71%, 22.25% and 29.24, respectively. It demonstrated that high temperature stress significantly induced the down-regulation of DNA methylation level and up-regulation of the full methylation rate in P. ternata genome. This study provides a preliminary theoretical reference for analyzing the mechanism of P. ternata responding to high temperature stress from the epigenetic perspective.

Cooperative Nanoparticle System for Photothermal Tumor Treatment without Skin Damage.

How to ablate tumors without using skin-harmful high laser irradiance remains an ongoing challenge for photothermal therapy. Here, we achieve this with a cooperative nanosystem consisting of gold nanocage (AuNC) "activator" and a cationic mammalian-membrane-disruptive peptide, cTL, as photothermal antenna and anticancer agent, respectively. Specifically, this nanosystem is prepared by grafting cTL onto AuNC via a Au-S bond, followed by attachment of thiolated polyethylene glycol (PEG) for stealth effects. Upon NIR irradiation at skin-permissible dosage, the resulting cTL/PEG-AuNC nanoparticle effectively ablates both irradiated and nonirradiated cancer cells, likely owing to cTL being responsively unleashed by intracellular thiols exposed to cTL/PEG-AuNC via membrane damage initiated by AuNC's photothermal effects and deteriorated by the as-released cTL. When administered systematically in a mouse model, cTL/PEG-AuNC populates tumors through their porous vessels and effectively destroys them without damaging skin.

Erythrocyte membrane is an alternative coating to polyethylene glycol for prolonging the circulation lifetime of gold nanocages for photothermal therapy.

Gold nanocages (AuNCs), which have tunable near-infrared (NIR) absorption and intrinsically high photothermal conversion efficiency, have been actively investigated as photothermal conversion agents for photothermal therapy (PTT). The short blood circulation lifetime of AuNCs, however, limits their tumor uptake and thus in vivo applications. Here we show that such a limitation can be overcome by cloaking AuNCs with red blood cell (RBC) membranes, a natural stealth coating. The fusion of RBC membranes over AuNC surface does not alter the unique porous and hollow structures of AuNCs, and the resulting RBC-membrane-coated AuNCs (RBC-AuNCs) exhibit good colloidal stability. Upon NIR laser irradiation, the RBC-AuNCs demonstrate in vitro photothermal effects and selectively ablate cancerous cells within the irradiation zone as do the pristine biopolymer-stealth-coated AuNCs. Moreover, the RBC-AuNCs exhibit significantly enhanced in vivo blood retention and circulation lifetime compared to the biopolymer-stealth-coated counterparts, as demonstrated using a mouse model. With integrated advantages of photothermal effects from AuNCs and long blood circulation lifetime from RBCs, the RBC-AuNCs demonstrate drastically enhanced tumor uptake when administered systematically, and mice that received PPT cancer treatment modulated by RBC-AuNCs achieve 100% survival over a span of 45 days. Taken together, our results indicate that the long circulating RBC-AuNCs may facilitate the in vivo applications of AuNCs, and the RBC-membrane stealth coating technique may pave the way to improved efficacy of PPT modulated by noble metal nanoparticles.