De novo assembly and analysis of Polygonatum cyrtonema Hua and identification of genes involved in polysaccharide and saponin biosynthesis.

BACKGROUND: The investigation of molecular mechanisms involved in polysaccharides and saponin metabolism is critical for genetic engineering of Polygonatum cyrtonema Hua to raise major active ingredient content. Up to now, the transcript sequences are available for different tissues of P. cyrtonema, a wide range scanning about temporal transcript at different ages' rhizomes was still absent in P. cyrtonema. RESULTS: Transcriptome sequencing for rhizomes at different ages was performed. Sixty-two thousand six hundred thirty-five unigenes were generated by assembling transcripts from all samples. A total of 89 unigenes encoding key enzymes involved in polysaccharide biosynthesis and 56 unigenes encoding key enzymes involved in saponin biosynthesis. The content of total polysaccharide and total saponin was positively correlated with the expression patterns of mannose-6-phosphate isomerase (MPI), GDP-L-fucose synthase (TSTA3), UDP-apiose/xylose synthase (AXS), UDP-glucose 6-dehydrogenase (UGDH), Hydroxymethylglutaryl CoA synthase (HMGS), Mevalonate kinase (MVK), 2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase (ispF), (E)-4-hydroxy-3-methylbut-2-enyl-diphosphate synthase (ispG), 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (ispH), Farnesyl diphosphate synthase (FPPS). Finally, a number of key genes were selected and quantitative real-time PCR were performed to validate the transcriptome analysis results. CONCLUSIONS: These results create the link between polysaccharides and saponin biosynthesis and gene expression, provide insight for underlying key active substances, and reveal novel candidate genes including TFs that are worth further exploration for their functions and values.

Injectable and Radiopaque Liquid Metal/Calcium Alginate Hydrogels for Endovascular Embolization and Tumor Embolotherapy.

Improved endovascular embolization can contribute to assistant treatment for patients. However, many traditional embolic materials, such as metal microcoils or liquid embolic agents, are associated with limitations of coil migration or recanalization. Herein, as the first trial, an injectable and radiopaque liquid metal/calcium alginate (LM/CA) hydrogel is introduced and fabricated as a candidate for endovascular embolization and tumor embolotherapy through developing LM droplets as radiopaque units into biocompatible calcium alginate cross-linked network. The adoption of LM droplets makes hydrogels radiopaque under X-ray and CT scan, which significantly facilitates the tracking of material location during surgical vascular operation. In addition, in vitro and in vivo experiments prove that such smart hydrogel could convert from liquid to solid rapidly via cross-linking, showing pretty flexible and controllable functions. Benefiting from these properties, the hydrogel can be performed in blood vessels through injection via syringes and then served as an embolic material for endovascular embolization procedures. In vivo experiments demonstrate that such hydrogels can occlude arteries and block blood flow until they ultimately lead to ischemic necrosis of tumors and partial healthy tissues. Overall, the present LM/CA hydrogels are promising to be developed as new generation embolic materials for future tumor embolotherapy.

Liquid metal angiography for mega contrast X-ray visualization of vascular network in reconstructing in-vitro organ anatomy.

Visualization on the anatomical vessel networks plays a vital role in the physiological or pathological investigations. However, so far it still remains a big challenge to identify the fine structures of the smallest capillary vessel networks via conventional imaging ways. Here, the room temperature liquid metal angiography was proposed for the first time to generate mega contrast X-ray images for multiscale vasculature mapping. Particularly, gallium was adopted as the room temperature liquid metal contrast agent and infused into the vessels of in vitro pig hearts and kidneys. We scanned the samples under X-ray and compared the angiograms with those obtained via conventional contrast agent--the iohexol. As quantitatively demonstrated by the grayscale histograms and numerical indexes, the contrast of the vessels to the surrounding tissues in the liquid metal angiograms is orders higher than that of the iohexol enhanced images. And the angiogram has reached detailed enough width of 0.1 mm for the tiny vessels, which indicated that the capillaries can be clearly distinguished under the liquid metal enhanced images. Further, with tomography from the micro-CT, we also managed to reconstruct the 3-D structures of the kidney vessels. Tremendous clarity and efficiency of the method over existing approaches have been experimentally clarified. It was disclosed that the usually invisible capillary networks now become distinctively clear in the gallium angiograms. This basic mechanism has generalized purpose and can be extended to a wide spectrum of 3-D computational tomographic areas. It opens a new soft tool for quickly reconstructing high-resolution spatial channel networks for scientific researches as well as engineering practices where complicated and time-consuming resections are no longer a necessity.