Mediator subunit MED8 interacts with heat shock transcription factor HSF3 to promote fucoxanthin synthesis in the diatom Phaeodactylum tricornutum.

Fucoxanthin, a natural carotenoid that has substantial pharmaceutical value due to its anticancer, antioxidant, antiobesity, and antidiabetic properties, is biosynthesized from glyceraldehyde-3-phosphate (G3P) via a series of enzymatic reactions. However, our understanding of the transcriptional mechanisms involved in fucoxanthin biosynthesis remains limited. Using reverse genetics, the med8 mutant was identified based on its phenotype of reduced fucoxanthin content, and the biological functions of MED8 in fucoxanthin synthesis were characterized using approaches such as gene expression, protein subcellular localization, protein-protein interaction and chromatin immunoprecipitation assay. Gene-editing mutants of MED8 exhibited decreased fucoxanthin content as well as reduced expression levels of six key genes involved in fucoxanthin synthesis, namely DXS, PSY1, ZDS-like, CRTISO5, ZEP1, and ZEP3, when compared to the wild-type (WT) strain. Furthermore, we showed that MED8 interacts with HSF3, and genetic analysis revealed their shared involvement in the genetic pathway governing fucoxanthin synthesis. Additionally, HSF3 was required for MED8 association with the promoters of the six fucoxanthin synthesis genes. In conclusion, MED8 and HSF3 are involved in fucoxanthin synthesis by modulating the expression of the fucoxanthin synthesis genes. Our results increase the understanding of the molecular regulation mechanisms underlying fucoxanthin synthesis in the diatom P. tricornutum.

Valorization of Phaeodactylum tricornutum for integrated preparation of diadinoxanthin and fucoxanthin.

Integrated preparation of high-purity carotenoids from marine microalgae using green and efficient methods still faces enormous challenges. In this study, valorization of the economic Phaeodactylum tricornutum using integrated preparation of diadinoxanthin (Ddx) and fucoxanthin (Fx) was explored containing four steps including algae cultivation, solvent extraction, ODS open-column chromatography, and ethanol precipitation for the first time. Several essential key factors were optimized for simultaneously extracting Ddx and Fx from P. tricornutum. ODS open-column chromatography was used to isolate Ddx and Fx. Purification of Ddx and Fx was accomplished using ethanol precipitation. After optimization, the purity of Ddx and Fx was more than 95%, and the total recovery rates of Ddx and Fx were approximately 55% and 85%, respectively. The purified Ddx and Fx were identified as all-trans-diadinoxanthin and all-trans-fucoxanthin, respectively. The antioxidant capacity of the purified Ddx and Fx was assessed using two tests in vitro: DPPH and ABTS radical assays.

High-Purity Fucoxanthin Can Be Efficiently Prepared from Isochrysis zhangjiangensis by Ethanol-Based Green Method Coupled with Octadecylsilyl (ODS) Column Chromatography.

The exploitation of new economically valuable microalgae as a sustainable source of minor high-value products can effectively promote the full utilization of microalgae. The efficient preparation of minor products from microalgae remains the challenge, owing to the coexistence of various components with a similar polarity in the microalgae biomass. In this study, a novel approach based on the sustainable-oriented strategy for fucoxanthin (FX) production was proposed, which consisted of four steps, including the culture of microalga, ethanol extraction, ODS column chromatography, and ethanol precipitation. The high-purity FX (around 95%) was efficiently obtained in a total recovery efficiency of 84.28 ± 2.56%. This study reveals that I. zhangjiangensis is a potentially promising feedstock for FX production and firstly provides a potentially eco-friendly method for the scale-up preparation of FX from the microalga I. zhangjiangensis.

Noniridescent structural color from enhanced electromagnetic resonances of particle aggregations and its applications for reconfigurable patterns.

HYPOTHESIS: The conventional noniridescent structural colors refer to the coherent scattering of visible light by the short-range ordered structures assembled from the small colloids (100-250 nm). Our hypothesis is that noniridescent structural color can be generated by the random aggregations of large silica particles through the enhanced electromagnetic resonances. EXPERIMENTS: The random aggregations of large silica particles (350-475 nm) were prepared through the infiltration of silica particles solution with the porous substrate. The mechanism of the structural color is investigated. Reconfigurable patterns are prepared. FINDINGS: Dissimilar to the conventional noniridescent colors, the angle-independent colors of silica aggregations originate from the enhanced electromagnetic resonances due to the random aggregation of the particles. The colors (blue, green, and red) and corresponding reflection peak positions of the particle aggregations can be well controlled by simply altering the size of the silica particles. Compared to the traditional prints with permanent patterns, reconfigurable patterns with large-area and multicolor can be fabricated by the repeatedly selective spray of water on the substrate pre-coated with noniridescent colors. This work provides new insight and greenway for the fabrication of noniridescent structural colors and reconfigurable patterns, and will promote their applications in soft display, green printing, and anti-counterfeiting.

Isolation and Purification of Fucoxanthin from Brown Seaweed Sargassum horneri Using Open ODS Column Chromatography and Ethanol Precipitation.

As an abundant marine xanthophyll, fucoxanthin (FX) exhibits a broad range of biological activities. The preparation of high-purity FX is in great demand, however, most of the available methods require organic solvents which cannot meet the green chemistry standard. In the present study, a simple and efficient purification approach for the purification of FX from the brown seaweed Sargassum horneri was carried out. The FX-rich ethanol extract was isolated by octadecylsilyl (ODS) column chromatography using ethanol-water solvent as a gradient eluent. The overwhelming majority of FX was successfully eluted by the ethanol-water mixture (9:1, v/v), with a recovery rate of 95.36%. A parametric study was performed to optimize the aqueous ethanol precipitation process by investigating the effects on the purity and recovery of FX. Under the optimal conditions, the purity of FX was 91.07%, and the recovery rate was 74.98%. Collectively, the eco-friendly method was cost-efficient for the purification of FX. The developed method provides a potential approach for the large-scale production of fucoxanthin from the brown seaweed Sargassum horneri.

Simple and efficient fabrication of multi-stage color-changeable photonic prints as anti-counterfeit labels.

Color changeable photonic prints (CCPPs) show their potential applications in high-level information storage and anti-counterfeiting, but usually suffer from the complex fabrication process and limited color variation. Here, a simple and efficient method is developed to generate CCPPs with multilevel tunable color contrasts by packing the solvent responsive photonic crystals with diverse cross-linking degrees and desired way. The key to the successful fabrication is to create and control over the optical response of each part of the CCPPs through altering the cross-linking degree of PCs and thus the affinity between the CCPPs and solvents. A CCPPs based anti-fake label with the encrypted information functionality which originates from reversible color change between dried state and swelling with the mixture of acetic acid and ethanol is investigated. Compared with conventional CCPPs, the as-prepared CCPPs can reveal multistage information depending on the volume fraction of ethanol. This work provides a new insight for the simple fabrication of CCPPs and will facilitate their applications in the information protection and high-level anti-counterfeiting.

Acoustic Bubble Suppression by Constructing a Hydrophilic Coating on HDPE Surface.

Ultrasonic bubbles on the solid surface of various sonochemical devices largely affect signal resolution due to the serious reflection/scattering of sound waves. The Laplace pressure of the cavitation bubble can be tuned by constructing an ultrathin hydrophilic layer, which leads to the solvation or pinching off of the bubbles from the surface. In this article, we successfully coated a polydopamine polymer layer on the high-density polyethylene (HDPE) surface. The formed hydrophilic layer with a contact angle of less than 45° almost completely eliminates the bubbles in both water and 32.5 vol % diesel exhaust fluid solutions upon sonication, which results in the operation of the piezoelectric sensor over 500 h, while the sensor with pure HDPE only ran for less than 2 h. Further, the coated sensors showed high stability under the temperatures of 60-80 °C. An improved mechanical property was confirmed via abrasion test, enabling long-term stability in harsh environments, including acidic urine and ultrasonic agitation. The acoustic bubble suppression via the hydrophilic polymer coating on HDPE surface displays broad applications, particularly with acoustic sensors, sonobuoys, and nondestructive surface detection in sonochemistry.

Improved antibacterial performance using hydrogel-immobilized lysozyme as a catalyst in water.

Silver nanoparticle-based catalysts are used extensively to kill bacteria in drinking water treatment. However secondary contamination and their high cost require scientists to seek alternatives with non-toxicity, high activity and low cost. In this article, we develop a new hydrogel-immobilized lysozyme (h-lysozyme) that shows excellent antibacterial performance, including high activity duration of up to 55 days, inhibition efficiency as high as 99.4%, good recycling capability of up to 11 cycles, a wide temperature window and extremely low concentration. The immobilized lysozyme displayed greatly improved bacterial inhibition with both Gram-negative E. coli and Gram-positive B. subtilis, which enables broad antibacterial applications in various water systems. In parallel, the non-toxic structure and high stability of the h-lysozyme without additional contamination make it a promising alternative to nanoparticle catalysts fur use in drinking water purification.

Oxygen-tuned nanozyme polymerization for the preparation of hydrogels with printable and antibacterial properties.

Nanozymes merge nanotechnology with biology and provide a lower cost and higher stability options, compared to that of natural enzymes. However, nanozyme catalyzed polymerization under physiological conditions is still a big challenge due to heavy oxygen inhibition. In this study, the simple glucose oxidase system can effectively adjust oxygen concentration and generate hydrogen peroxide, which assists in the realization of nanozyme-catalyzed polymerization. The nanozyme based hydrogel is printable due to its mild preparation with gradually increased viscosity. The antibacterial performance is ascribed to the in situ generated hydroxyl radical via the reaction of the bound nanozyme and glucose.