Engineered Protein-Iron Oxide Hybrid Biomaterial for MRI-traceable Drug Encapsulation.

Labeled protein-based biomaterials have become a popular for various biomedical applications such as tissue-engineered, therapeutic, or diagnostic scaffolds. Labeling of protein biomaterials, including with ultrasmall super-paramagnetic iron oxide (USPIO) nanoparticles, has enabled a wide variety of imaging techniques. These USPIO-based biomaterials are widely studied in magnetic resonance imaging (MRI), thermotherapy, and magnetically-driven drug delivery which provide a method for direct and non-invasive monitoring of implants or drug delivery agents. Where most developments have been made using polymers or collagen hydrogels, shown here is the use of a rationally designed protein as the building block for a meso-scale fiber. While USPIOs have been chemically conjugated to antibodies, glycoproteins, and tissue-engineered scaffolds for targeting or improved biocompatibility and stability, these constructs have predominantly served as diagnostic agents and often involve harsh conditions for USPIO synthesis. Here, we present an engineered protein-iron oxide hybrid material comprised of an azide-functionalized coiled-coil protein with small molecule binding capacity conjugated via bioorthogonal azide-alkyne cycloaddition to an alkyne-bearing iron oxide templating peptide, CMms6, for USPIO biomineralization under mild conditions. The coiled-coil protein, dubbed Q, has been previously shown to form nanofibers and, upon small molecule binding, further assembles into mesofibers via encapsulation and aggregation. The resulting hybrid material is capable of doxorubicin encapsulation as well as sensitive T2*-weighted MRI darkening for strong imaging capability that is uniquely derived from a coiled-coil protein.

The influence of water regime on cadmium uptake by Artemisia: A dominant vegetation in Poyang Lake wetland.

An analysis of the influence of water regime on the metal accumulation processes of wetland plants can improve the efficiency of phytoremediation. However, few studies have clearly explored the mechanism of influence of water regime on the process of accumulation of metals by the dominant vegetation in Poyang Lake wetland, the largest freshwater lake in China. The aim of this study was to investigate the influence of water regime (Flooding condition [FC], Dry condition [DC] and alternate dry and flooding condition [DFC]) on the accumulation of cadmium (Cd) by Artemisia selengensis Turcz. ex Bess., a dominant plant in the Poyang Lake wetland. The results indicated that FC treatment significantly enhanced the accumulation of Cd by Artemisia roots compared with DFC and DC treatments. In addition, the DFC treatment significantly increased the translocation of Cd from roots to shoots compared with the FC treatment. A multivariate statistical analysis indicated that the rhizosphere Cd fraction, iron plaque on the root surface and rhizosphere pH directly or indirectly significantly influence the process of accumulation of Cd. The conversion of exchangeable fraction to Fe/Mn oxide bound and organic fraction under the DFC and FC treatments decreased the accumulation of Cd in Artemisia. The formation of increased amounts of iron plaque under the FC treatment may enhance the accumulation of Cd in roots, while it may reduce the translocation of Cd to aboveground tissues. In addition, a higher rhizosphere pH under the FC treatment may promote accumulation of Cd in the root by inducing formation of iron plaque. Similarly, compared with the FC treatment, a lower rhizosphere pH and iron plaque can induce the processes of Cd translocation under the DFC treatment. Based on the bioaccumulation factor, translocation factor and the ratio of root/aerial Cd content, treatment with DC benefited the phytoextraction of Cd, while treatment with DFC and FC enhanced the phytostabilization of Cd by Artemisia. This study provides valuable information for deeply understanding the resilience of wetland ecosystems and for enhancing the phytoremediation with wetland plants using water management.

Overexpression of MaTPD1A impairs fruit and pollen development by modulating some regulators in Musa itinerans.

BACKGROUND: Pollen formation and development is important for crop fertility and is a key factor for hybrid development. Previous reports have indicated that Arabidopsis thaliana TAPETUM DETERMINANT1 (AtTPD1) and its rice (Oryza sativa) homolog, OsTPD1-like (OsTDL1A), are required for cell specialization and greatly affect pollen formation and development. Little is known about the role of the TPD1 homolog in banana pollen development. RESULTS: Here, we report the identification and characterization of TPD1 homologs in diploid banana (Musa itinerans) and examine their role in pollen development by overexpressing the closest homolog, MaTPD1A. MaTPD1A exhibits high expression in stamen and localizes in the plasma membrane. MaTPD1A-overexpressing plants produce no pollen grains and smaller and seedless fruit compared to wild-type plants. Transcriptome analysis showed that in plant hormone, starch and sucrose metabolism, and linolenic acid metabolism-related pathways were affected by overexpression of MaTPD1A, and the expression of several key regulators, such as PTC1 and MYB80, which are known to affect anther development, is affected in MaTPD1A-overexpressing lines. CONCLUSIONS: Our results indicate that MaTPD1A plays an important role in pollen formation and fruit development in diploid banana, possibly by affecting the expression of some key regulators of pollen development.

In-situ fabrication of Ag/P-g-C3N4 composites with enhanced photocatalytic activity for sulfamethoxazole degradation.

A series of Ag/P-g-C3N4 composites with different Ag content were synthesized for the first time by thermal polymerization combined with photo-deposition method. The composites were characterized by X-ray powder diffraction, field emission scanning electron microscope coupled with energy-dispersive X-ray spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectra, N2 absorption-desorption and X-ray photoelectron spectroscopy. Ag was successfully dispersed on the surface of P-g-C3N4. The photocatalytic performance of P-g-C3N4 and Ag/P-g-C3N4 was evaluated by degrading sulfamethoxazole (SMX) under visible light irradiation. In the presence of 5% Ag/P-g-C3N4, 100% of SMX was degraded within 20 min. The enhanced photocatalytic activity of Ag/P-g-C3N4 was attributed to the surface plasmon resonance effect of metallic Ag and Schottky barrier formed on the interface between Ag and P-g-C3N4, which could speed up the generation rate of electrons and holes and inhibit the recombination of photogenerated electron-hole pairs. The radical quenching tests indicated that holes and superoxide radicals were the dominant active species involved in SMX degradation. The synthesized materials maintained high catalytic activity after five cycle runs. The concentration and the intermediates during the degradation process were determined by LC-MS/MS, and the tentative degradation pathways of SMX in photocatalytic system were proposed.

Recent Progress in Light-Triggered Nanotheranostics for Cancer Treatment.

Treatments of high specificity are desirable for cancer therapy. Light-triggered nanotheranostics (LTN) mediated cancer therapy could be one such treatment, as they make it possible to visualize and treat the tumor specifically in a light-controlled manner with a single injection. Because of their great potential in cancer therapy, many novel and powerful LTNs have been developed, and are mainly prepared from photosensitizers (PSs) ranging from small organic dyes such as porphyrin- and cyanine-based dyes, semiconducting polymers, to inorganic nanomaterials such as gold nanoparticles, transition metal chalcogenides, carbon nanotubes and graphene. Using LTNs and localized irradiation in combination, complete tumor ablation could be achieved in tumor-bearing animal models without causing significant toxicity. Given their great advances and promising future, we herein review LTNs that have been tested in vivo with a highlight on progress that has been made in the past a couple of years. The current challenges faced by these LTNs are also briefly discussed.

[Responses of Physiological Indices of Typical Submerged Macrophytes to Water Quality in Taihu Lake].

It was well known that physiological indices of submerged macrophytes could reflect change of water quality. The correlation between physiological indices of submerged macrophytes and change of water quality was studied under the cooperation of in-situ monitoring and lab analysis, combined with measuring Chlorophyll and free proline (PRO) contents as well as peroxidase (POD) activities in the leaves of Potamogeton wrightii Morong and Potamogeton crispus L. under different water quality and nutrition status. The results showed: ①there were significant spatial differences among water factors and the comprehensive eutrophication index (TLI) of distribution areas of Potamogeton wrightii Morong and Potamogeton crispus L. Mesotrophic water was more suitable for the growth of Potamogeton wrightii Morong, while Potamogeton crispus L. grew well in eutrophic water. ②there were significant spatial differences among physiological indices of Potamogeton wrightii Morong and Potamogeton crispus L. in Taihu Lake. Besides, there were significant relationships between Chlorophyll contents, POD activities of two species and TLI. ③water transparency as well as nitrogen and phosphorus nutrition were important factors leading to changes in Chlorophyll contents and POD activities of Potamogeton wrightii Morong and Potamogeton crispus L.. The findings from this study indicate that physiological properties of Potamogeton wrightii Morong and Potamogeton crispus L. have a very close correlation with nutrition status and physiochemical properties of water.

Stereochemical control of polymorph transitions in nanoscale reactors.

Crystallization of glycine in the cylindrical nanopores of anodic aluminum oxide (AAO) revealed the formation of metastable ß-glycine in pores having diameters less than 200 nm. Two-dimensional X-ray microdiffraction indicated that the [010] axis of the embedded ß-glycine nanocrystals coincided with the pore direction, identical to behavior observed previously in the cylindrical nanopores of polymer monoliths. Whereas the ß-glycine nanocrystals were stable indefinitely in ambient air and persisted upon heating, they transformed to the α polymorph upon standing at room temperature and 90% relative humidity (RH). The α-glycine nanocrystals were oriented with the [010] axis nearly perpendicular to the pore direction, reflecting a nearly 90° rotation of the glycine molecules during the transition. When the ß-glycine nanocrystals were formed in the AAO cylinders in the presence of small amounts of racemic hydrophobic amino acid auxiliaries, which are known to bind selectively to the (010) and (010) faces on the fast-growing end of ß-glycine enantiomorphs, the ß â†’ α phase transition at 90% RH was suppressed. In contrast, ß-glycine nanocrystals grown in the presence of an enantiopure amino acid auxiliary, which binds to the fast-growing end of only one of the enantiomorphs, thus suppressing its formation and leaving the other enantiomorph unperturbed, transformed into the α polymorph under the same conditions. This observation confirms that binding of an amino acid to the {010} faces is stereoselective and that access of water to these faces is essential for the transition to the α polymorph.