The Complexity of Volatile Terpene Biosynthesis in Roses: Particular Insights into ß-Citronellol Production.

The fascinating scent of rose (Rosa genus) flowers has captivated human senses for centuries, making them one of the most popular and widely used floral fragrances. Despite much progress over the last decade, many biochemical pathways responsible for rose scents remain unclear. We analyzed the floral scent compositions from various rose varieties and selected the modern cultivar Rosa hybrida 'Double Delight' as a model system to unravel the formation of rose dominant volatile terpenes, which contribute substantially to the rose fragrance. Key genes involved in rose terpene biosynthesis were functionally characterized. Cytosolic geranyl diphosphate (GPP) generated by geranyl/farnesyl diphosphate synthase (G/FPPS1) catalysis, played a pivotal role in rose scent production, and terpene synthases (TPSs) in roses play an important role in the formation of most volatile terpenes, but not for geraniol, citral or ß-citronellol. Subsequently, a series of enzymes, including geraniol dehydrogenase (GeDH), geranial reductase (GER), 12-oxophytodienoate reductase (OPR) and citronellal reductase (CAR), were characterized as involved in the transformation of geraniol to ß-citronellol in roses through three successive steps. Interestingly, the ß-citronellol biosynthesis pathway appears to be conserved in other horticultural plants like Lagerstroemia caudata and Paeonia lactiflora. Our findings provide valuable insights into the biosynthesis of rose volatile terpenoid compounds and offer essential gene resources for future breeding and molecular modification efforts.

Allelic variation of terpene synthases drives terpene diversity in the wild species of the Freesia genus.

Terpene synthases (TPSs) play pivotal roles in conferring the structural diversity of terpenoids, which are mainly emitted from flowers, whereas the genetic basis of the release of floral volatile terpenes remains largely elusive. Though quite similar in sequence, TPS allelic variants still function divergently, and how they drive floral terpene diversity in closely related species remains unknown. Here, TPSs responsible for the floral scent of wild Freesia species were characterized, and the functions of their natural allelic variants, as well as the causal amino acid residues, were investigated in depth. Besides the 8 TPSs previously reported in modern cultivars, 7 additional TPSs were functionally evaluated to contribute to the major volatiles emitted from wild Freesia species. Functional characterization of allelic natural variants demonstrated that allelic TPS2 and TPS10 variants changed the enzymatic capacity while allelic TPS6 variants drove the diversity of floral terpene products. Further residue substitution analysis revealed the minor residues determining the enzyme catalytic activity and product specificity. The clarification of TPSs in wild Freesia species reveals that allelic TPS variants evolved differently to determine the interspecific floral volatile terpenes in the genus and might be used for modern cultivar improvement.

Improving Room-Temperature Li-Metal Battery Performance by In Situ Creation of Fast Li+ Transport Pathways in a Polymer-Ceramic Electrolyte.

Composite polymer-ceramic electrolytes have shown considerable potential for high-energy-density Li-metal batteries as they combine the benefits of both polymers and ceramics. However, low ionic conductivity and poor contact with electrodes limit their practical usage. In this study, a highly conductive and stable composite electrolyte with a high ceramic loading is developed for high-energy-density Li-metal batteries. The electrolyte, produced through in situ polymerization and composed of a polymer called poly-1,3-dioxolane in a poly(vinylidene fluoride)/ceramic matrix, exhibits excellent room-temperature ionic conductivity of 1.2 mS cm-1 and high stability with Li metal over 1500 h. When tested in a Li|electrolyte|LiFePO4 battery, the electrolyte delivers excellent cycling performance and rate capability at room temperature, with a discharge capacity of 137 mAh g-1 over 500 cycles at 1 C. Furthermore, the electrolyte not only exhibits a high Li+ transference number of 0.76 but also significantly lowers contact resistance (from 157.8 to 2.1 Ω) relative to electrodes. When used in a battery with a high-voltage LiNi0.8 Mn0.1 Co0.1 O2 cathode, a discharge capacity of 140 mAh g-1 is achieved. These results show the potential of composite polymer-ceramic electrolytes in room-temperature solid-state Li-metal batteries and provide a strategy for designing highly conductive polymer-in-ceramic electrolytes with electrode-compatible interfaces.

Functional Characterization of a (E)-ß-Ocimene Synthase Gene Contributing to the Defense against Spodoptera litura.

Soybean is a worldwide crop that offers valuable proteins, fatty acids, and phytonutrients to humans but is always damaged by insect pests or pathogens. Plants have captured sophisticated defense mechanisms in resisting the attack of insects and pathogens. How to protect soybean in an environment- or human-friendly way or how to develop plant-based pest control is a hotpot. Herbivore-induced plant volatiles that are released by multiple plant species have been assessed in multi-systems against various insects, of which (E)-ß-ocimene has been reported to show anti-insect function in a variety of plants, including soybean. However, the responsible gene in soybean is unknown, and its mechanism of synthesis and anti-insect properties lacks comprehensive assessment. In this study, (E)-ß-ocimene was confirmed to be induced by Spodoptera litura treatment. A plastidic localized monoterpene synthase gene, designated as GmOCS, was identified to be responsible for the biosynthesis of (E)-ß-ocimene through genome-wide gene family screening and in vitro and in vivo assays. Results from transgenic soybean and tobacco confirmed that (E)-ß-ocimene catalyzed by GmOCS had pivotal roles in repelling a S. litura attack. This study advances the understanding of (E)-ß-ocimene synthesis and its function in crops, as well as provides a good candidate for further anti-insect soybean improvement.

CircSAMD11 facilitates progression of cervical cancer via regulating miR-503/SOX4 axis through Wnt/ß-catenin pathway.

Cervical cancer (CC) is a common gynaecological malignant tumour with a high mortality rate. Circular RNAs (circRNAs) play a critical role in tumour occurrence and development. This study aimed to investigate the function and molecular basis of hsa_circ_0009189 (circSAMD11) in CC development. RNA levels were determined by qRT-PCR, and protein expression was measured by western blot. Cell proliferation, migration, invasion and apoptosis were detected by Cell Counting Kit-8 (CCK-8), colony formation, Transwell and flow cytometry assays. The relationship between miR-503 and circSAMD11/SOX4 was validated via dual-luciferase reporter assay, RIP or RNA pull-down assay. Xenograft assay was conducted to test tumour growth in vivo. CircSAMD11 and SOX4 levels were elevated, while miR-503 level was reduced in CC tissues and cells. Knockdown of circSAMD11 suppressed CC cell proliferation, migration and invasion and accelerated apoptosis. CircSAMD11 was localised in cytoplasm and directly targeted miR-503. Also, circSAMD11 sponged miR-503 to modulate SOX4 expression. Additionally, circSAMD11 regulated CC progression via absorbing miR-503 or modulating SOX4. Besides, depletion of circSAMD11 hindered tumorigenesis in vivo. CircSAMD11 contributed to CC progression by regulating miR-503/SOX4 signalling and activating Wnt/ß-catenin pathway, which provides a promising therapeutic target for cervical cancer.

In Vivo Coinstantaneous Identification of Hepatocellular Carcinoma Circulating Tumor Cells by Dual-Targeting Magnetic-Fluorescent Nanobeads.

Circulating tumor cells (CTCs) have been considered as a potential biomarker for evaluation of cancer metastasis and prognosis, especially in hepatocellular carcinoma (HCC). However, the isolation and detection of rare CTCs in HCC patients face enormous challenges due to omittance and nonspecific binding. We previously designed a small molecular NIR fluoresent agent, named MLP, which had high affinity with a tumor cell-overexpressed enzyme, aminopeptidase N (APN). Based on that, in this work we introduced a novel strategy via coassembling the antiepithelial cell adhesion molecule (EpCAM) antibody and MLPinto theFe3O4 magnetic nanobeads (MB-MLP-EpCAM) to isolate and identify HCC-CTCs coinstantaneously. MB-MLP-EpCAM significantly improved the CTC-capture efficiency (>85%) without sacrificing cell viability (>90%). Most importantly, the advantages of precise dual-targetability, high resolution of fluorescence imaging, and prominent selectivity make our nanoplatform have great potential to achieve in vivo real-time identification and monitoring of CTCs clinically.

MYB transcription factors GmMYBA2 and GmMYBR function in a feedback loop to control pigmentation of seed coat in soybean.

Soybean has undergone extensive selection pressures for seed nutrient composition and seed color during domestication, but the major genetic loci controlling seed coat color have not been completely understood, and the transcriptional regulation relationship among the loci remains elusive. Here, two major regulators, GmMYBA2 and GmMYBR, were functionally characterized as an anthocyanin activator and repressor, respectively. Ectopic expression of GmMYBA2 in soybean hairy roots conferred the enhanced accumulation of delphinidin and cyanidin types of anthocyanins in W1t and w1T backgrounds, respectively, through activating anthocyanin biosynthetic genes in the reported loci. The seed coat pigmentation of GmMYBA2-overexpressing transgenic plants in the W1 background mimicked the imperfect black phenotype (W1/w1, i, R, t), suggesting that GmMYBA2 was responsible for the R locus. Molecular and biochemical analysis showed that GmMYBA2 interacted with GmTT8a to directly activate anthocyanin biosynthetic genes. GmMYBA2 and GmMYBR might form a feedback loop to fine-tune seed coat coloration, which was confirmed in transgenic soybeans. Both GmTT8a and GmMYBR that were activated by GmMYBA2 in turn enhanced and obstructed the formation of the GmMYBA2-GmTT8a module, respectively. The results revealed the sophisticated regulatory network underlying the soybean seed coat pigmentation loci and shed light on the understanding of the seed coat coloration and other seed inclusions.

Total synthesis and biological evaluation of 7-hydroxyneolamellarin A as hypoxia-inducible factor-1α inhibitor for cancer therapy.

7-Hydroxyneolamellarin A (7-OH-Neo A, 1), a natural marine product derived from sponge Dendrilla nigra, was first synthesized with 10% overall yield under the instruction of convergent synthetic strategy. We found that 7-OH-Neo A could attenuate the accumulation of hypoxia-inducible factor-1α (HIF-1α) protein and inhibit vascular epidermal growth factor (VEGF) transcriptional activity, showing well inhibitory effect on HIF-1 signaling pathway. Meantime, 7-OH-Neo A had the well anti-tumor activities, such as inhibiting tumor angiogenesis, proliferation, migration and invasion. More importantly, 7-OH-Neo A exhibited profound anti-tumor effect in mice breast cancer model by suppressing the accumulation of HIF-1α in tumor tissue. Mechanism study demonstrated that 7-OH-Neo A might target the protein with the ability of stabilizing HIF-1α in hypoxia. Due to the excellent water solubility, superior anti-tumor activity and good biocompatibility, 7-OH-Neo A shows the promising potential for being exploited as an anti-tumor agent in near future.

Synthesis and biological evaluation of NO-donor containing photosensitizers to induce ferroptosis of cancer cells.

Photodynamic therapy (PDT) is a non-invasive treatment method for tumors by exciting photosensitizers (PS) upon light irradiation to generate cytotoxic reactive oxygen species (ROS). However, the low oxygen concentration near the tumor tissue limits the therapeutic effect of PDT. Herein, we synthesized six chlorin e6 derivatives containing NO-donors to enhance their antitumor activity by synergistic effect of ROS and NO. The results revealed that the new NO-donor containing photosensitizers (PS-NO) exhibited more potent photodynamic activity than chlorin e6, and the introduction of NO donor moieties to chlorin e6 increased the level of NO and ROS in cells. The addition of Ferrostatin-1, a ferroptosis inhibitor, markedly reduced the photodynamic activity of PS-NO as well as the level of NO and ROS in cells. Mechanism studies further showed that PS-NO could reduce intracellular GSH level, inhibit GPX4 activity and promote malondialdehyde (MDA) accumulation upon light irradiation, which suggested the ferroptosis mechanism underlying the PDT effect of PS-NO.

Synthesis and evaluation of 3-(phenylethynyl)-1,1'-biphenyl-2-carboxylate derivatives as new HIF-1 inhibitors.

Selaginellins are a type of rare natural products from the genus Selaginella with unusual alkynyl phenol skeletons and extensive biological activities. Previous structural simplification of these natural compounds afforded a series of diaryl acetylene derivatives with hypoxia-inducible factor 1 (HIF-1) inhibitory activity. In this study, we synthesized thirty compounds by stepwise optimization using methyl 3-(4-methoxylphenyl ethynyl)-[4'-methoxyl-1,1'-biphenyl]-2-carboxylate (1a) as a lead compound and evaluated their HIF-1 inhibitory activity by dual luciferase reporter assay. Among them, compound 9i displayed the most potent HIF-1 inhibitory activity (IC50 = 1.5 ± 0.03 µM) with relatively low cytotoxicity. Under hypoxia, compound 9i showed no effect on the accumulation of HIF-1α protein in western blot analysis, but could down-regulate the expression of VEGF mRNA, the downstream target gene of HIF-1 pathway. Cell-based activity assay demonstrated that compound 9i could inhibit the hypoxia-induced migration, invasion and proliferation of HeLa cells at the concentrations of 1 ~ 5 µM. In mouse breast cancer xenograft model, compound 9i exhibited obvious tumor growth inhibition and very low toxicity at a dose of 15 mg/kg. The results suggested that compound 9i would be a potential antitumor agent via HIF-1 pathway inhibition.