Over the past few decades, two-dimensional (2D) and layered materials have emerged as new fields. Due to the zero-band-gap nature of graphene and the low photocatalytic performance of MoS2, more ...advanced semiconducting 2D materials have been prompted. As a result, semiconductor black phosphorus (BP) is a derived cutting-edge post-graphene contender for nanoelectrical application, because of its direct-band-gap nature. For the first time, we report on robust BP@TiO2 hybrid photocatalysts offering enhanced photocatalytic performance under light irradiation in environmental and biomedical fields, with negligible affected on temperature and pH conditions, as compared with MoS2@TiO2 prepared by the identical synthesis method. Remarkably, in contrast to pure few layered BP, which, due to its intrinsic sensitivity to oxygen and humidity was readily dissolved after just several uses, the BP@TiO2 hybrid photocatalysts showed a ~92% photocatalytic activity after 15 runs. Thus, metal-oxide-stabilized BP photocatalysts can be practically applied as a promising alternative to graphene and MoS2.
We report an effect involving hydrogen (H2)-plasma-treated nanoporous TiO2(H-TiO2) photocatalysts that improve photocatalytic performance under solar-light illumination. H-TiO2 photocatalysts were ...prepared by application of hydrogen plasma of assynthesized TiO2(a-TiO2) without annealing process. Compared with the a-TiO2, the H-TiO2 exhibited high anatase/brookite bicrystallinity and a porous structure. Our study demonstrated that H2 plasma is a simple strategy to fabricate H-TiO2 covering a large surface area that offers many active sites for the extension of the adsorption spectra from ultraviolet (UV) to visible range. Notably, the H-TiO2 showed strong ·OH free-radical generation on the TiO2 surface under both UV- and visible-light irradiation with a large responsive surface area, which enhanced photocatalytic efficiency. Under solar-light irradiation, the optimized H-TiO2 120(H2-plasma treatment time: 120 min) photocatalysts showed unprecedentedly excellent removal capability for phenol (Ph), reactive black 5(RB 5), rhodamine B (Rho B) and methylene blue (MB) - approximately four-times higher than those of the other photocatalysts (a-TiO2 and P25) - resulting in complete purification of the water. Such well-purified water (>90%) can utilize culturing of cervical cancer cells (HeLa), breast cancer cells (MCF-7), and keratinocyte cells (HaCaT) while showing minimal cytotoxicity. Significantly, H-TiO2 photocatalysts can be mass-produced and easily processed at room temperature. We believe this novel method can find important environmental and biomedical applications.
Nannochloropsis is a marine microalga that has been extensively studied. The major carotenoid produced by this group of microalgae is violaxanthin, which exhibits anti-inflammatory, anti-photoaging, ...and antiproliferative activities. Therefore, it has a wide range of potential applications. However, large-scale production of this pigment has not been much studied, thereby limiting its industrial application.
To develop a novel strain producing high amount of violaxanthin, various Nannochloropsis species were isolated from seawater samples and their violaxanthin production potential were compared. Of the strains tested, N. oceanica WS-1 exhibited the highest violaxanthin productivity; to further enhance the violaxanthin yield of WS-1, we performed gamma-ray-mediated random mutagenesis followed by colorimetric screening. As a result, Mutant M1 was selected because of its significant higher violaxanthin content and biomass productivity than WS-1 (5.21 ± 0.33 mg g
and 0.2101 g L
d
, respectively). Subsequently, we employed a 10 L-scale bioreactor to confirm the large-scale production potential of M1, and the results indicated a 43.54 % increase in violaxanthin production compared with WS-1. In addition, comparative transcriptomic analysis performed under normal light condition identified possible mechanisms associated with remediating photo-inhibitory damage and other key responses in M1, which seemed to at least partially explain enhanced violaxanthin content and delayed growth.
Nannochloropsis oceanica mutant (M1) with enhanced violaxanthin content was developed and its physiological characteristics were investigated. In addition, enhanced production of violaxanthin was demonstrated in the large-scale cultivation. Key transcriptomic responses that are seemingly associated with different physiological responses of M1 were elucidated under normal light condition, the details of which would guide ongoing efforts to further maximize the industrial potential of violaxanthin producing strains.
Recently, extracellular vesicles (EVs) have been developed as therapeutic targets for various diseases. Biodistribution is crucial for EVs intended for therapeutic purposes because it can determine ...the degree of on‐ and off‐target effects. This study aimed to explore techniques to evaluate the biodistribution of unmodified EVs. We devised a novel quantitative polymerase chain reaction (qPCR)‐based assay to detect unmodified EVs by targeting mitochondrial deoxyribonucleic acid (mtDNA), a constituent of EVs. We focused on specific mtDNA regions that exhibited homologous variations distinct from their rodent mtDNA counterparts to establish this analytical approach. Herein, we successfully designed primers and probes targeting human and rodent mtDNA sequences and developed a highly specific and sensitive qPCR method. Furthermore, the quantification range of EVs isolated from various cells differed based on the manufacturer and cell source. IRDye 800CW‐labelled Expi293F EV mimetics were administered to the animals via the tail vein to compare the imaging test and mtDNA‐qPCR results. The results obtained from imaging tests and mtDNA‐qPCR to investigate EV biodistribution patterns revealed differences. The results revealed that our newly developed method effectively determined the biodistribution of unmodified EVs with high sensitivity and reproducibility.
Toxoplasma gondii, a ubiquitous, intracellular parasite of the phylum Apicomplexa, infects an estimated one-third of the human population as well as a broad range of warm-blooded animals. We have ...observed that some tyrosine kinase inhibitors suppressed the growth of T. gondii within host ARPE-10 cells. Among them, afatinib, human epithermal growth factor receptor 2 and 4 (HER2/4) inhibitor, may be used as a therapeutic agent for inhibiting parasite growth with minimal adverse effects on host. In this report, we conducted a proteomic analysis to observe changes in host proteins that were altered via infection with T. gondii and the treatment of HER2/4 inhibitors. Secreting proteins were subjected to a procedure of micor basic reverse phase liquid chromatography, nano-liquid chromatography-mass spectrometry, and ingenuity pathway analysis serially. As a result, the expression level of heterogeneous nuclear ribonucleoprotein K, semaphorin 7A, a GPI membrane anchor, serine/threonine-protein phosphatase 2A, and calpain small subunit 1 proteins were significantly changed, and which were confirmed further by western blot analysis. Changes in various proteins, including these 4 proteins, can be used as a basis for explaining the effects of T. gondii infections and HER2/4 inhibitors.
Hikeshi is a nuclear transport receptor required for cell survival after stress. It mediates heat‐shock‐induced nuclear import of 70 kDa heat‐shock proteins (Hsp70s) through interactions with ...FG‐nucleoporins (FG‐Nups), which are proteins in nuclear pore complexes (NPCs). Here, the crystal structure of human Hikeshi is presented at 1.8 Å resolution. Hikeshi forms an asymmetric homodimer that is responsible for the interaction with Hsp70s. The asymmetry of Hikeshi arises from the distinct conformation of the C‐terminal domain (CTD) and the flexibility of the linker regions of each monomer. Structure‐guided mutational analyses showed that both the flexible linker region and the CTD are important for nuclear import of Hsp70. Pull‐down assays revealed that only full‐length Hsp70s can interact with Hikeshi. The N‐terminal domain (NTD) consists of a jelly‐roll/β‐sandwich fold structure which contains hydrophobic pockets involved in FG‐Nup recognition. A unique extended loop (E‐loop) in the NTD is likely to regulate the interactions of Hikeshi with FG‐Nups. The crystal structure of Hikeshi explains how Hikeshi participates in the regulation of nuclear import through the recognition of FG‐Nups and which part of Hikeshi affects its binding to Hsp70. This study is the first to yield structural insight into this highly unique import receptor.
Recently, the appeal of 2D black phosphorus (BP) has been rising due to its unique optical and electronic properties with a tunable band gap (≈0.3–1.5 eV). While numerous research efforts have ...recently been devoted to nano‐ and optoelectronic applications of BP, no attention has been paid to promising medical applications. In this article, the preparation of BP‐nanodots of a few nm to <20 nm with an average diameter of ≈10 nm and height of ≈8.7 nm is reported by a modified ultrasonication‐assisted solution method. Stable formation of nontoxic phosphates and phosphonates from BP crystals with exposure in water or air is observed. As for the BP‐nanodot crystals’ stability (ionization and persistence of fluorescent intensity) in aqueous solution, after 10 d, ≈80% at 1.5 mg mL−1 are degraded (i.e., ionized) in phosphate buffered saline. They showed no or little cytotoxic cell‐viability effects in vitro involving blue‐ and green‐fluorescence cell imaging. Thus, BP‐nanodots can be considered a promising agent for drug delivery or cellular tracking systems.
Black phosphorus (BP)‐nanodots are prepared using a simple ultrasonication‐assisted solution method. Compared to conventional semiconductor quantum dots, BP‐nanodots present little in vitro cytotoxicity and further blue‐ and green‐fluorescent bioimaging roles under excitations of UV and visible light, showing potential as novel drug delivery carriers in biomedical applications.
In the nucleus, RanGTP binding to importin dissociates the cargo. On the other hand, RanGTP enables exportin to bind export cargo and form the export complex by each exportin's own cargo selection ...mechanism. Here, we present two X-ray structures for Exportin-5 (Exp-5) alone and Exp-5:RanGTP intermediate complex. The structure of Exp-5 adopts a ring-shaped closed conformation by C-terminal anchor residues 1,167–1,179, interacting with N-terminal heat repeats 4–9. The closed form of Exp-5 is important for the stability of the cargo-free state. Interaction between Exp-5 and RanGTP induces elimination of intramolecular contacts of the C-terminal anchor. A large movement of N-terminal 1–9th heat repeats and C-terminal 19–20th heat repeats creates an open space for RanGTP accommodation. Exp-5 in Exp-5:RanGTP and Exp-5:RanGTP:pre-miRNA adopts the same conformation. RanGTP binding to Exp-5 creates a selective molecular cage area for accepting its cargoes, such as small double-stranded RNAs, without conformational change in Exp-5:RanGTP.
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•Exp-5 alone structure showed a closed conformation•Exp-5s in Exp-5:RanGTP and Exp-5:RanGTP:pre-miRNA adopt the same conformation•RanGTP binding to Exp-5 creates a selective cage for pre-miRNAs and small ds-RNAs
Yamazawa et al. determine structures of Exp-5 alone and Exp-5:RanGTP. The intramolecular interaction between the C-terminal anchor and N terminus of Exp-5 alone is important for the stability of cargo-free Exp-5. Exp-5 in complex with RanGTP creates a cage for accepting pre-miRNAs without conformational change in Exp-5:RanGTP.
Microalgae have been widely considered for the production of valuable products, such as lipid-based biofuel, value-added pigments, and anti-photo aging reagents. More recently, microalgae have been ...considered an alternative host for recombinant protein production because of their economic benefits and ecofriendly characteristics. Additionally, many microalgal strains identified to date are generally recognized as safe (GRAS); therefore, the use of microalgae-based technology is promising. However, basic studies on the genetic engineering of microalgae are rare, despite their importance. Particularly, inducible promoter systems that can be applied for strain engineering or recombinant protein production are rarely studied; hence, a number of challenging issues remain unsolved. Therefore, in this study, we focused on the development of a convenient and compact-inducible promoter system that can be used in microalgae. Based on previous success with plant systems, we employed the alcohol-inducible AlcR-P
alc
A
system, which originates from the filamentous fungus,
Aspergillus nidulans
. This system comprises only two components, a regulatory protein, AlcR, and an inducible promoter, P
alc
A
. Therefore, construction and transformation of the gene cassettes can be easily performed. Ethanol-dependent gene expression was observed in the transformants with no significant growth retardation or inducer consumption observed in the cells cultivated under optimized conditions.
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