Constructing 2D Polyphenols-Based Crosslinked Networks for Ultrafast and Selective Uranium Extraction from Seawater.

The role of tannins (TA), a well-known abundant and ecologically friendly chelating ligand, in metal capture has long been studied. Different kinds of TA-containing adsorbents are synthesized for uranium capture, while most adsorbents suffer from unfavorable adsorption kinetics. Herein, the design and preparation of a TA-containing 2D crosslinked network adsorbent (TANP) is reported. The ≈1.8-nanometer-thick TANP films curl up into micrometer-scale pores, which contribute to fast mass transfer and full exposure of active sites. The coordination environment of uranyl (UO2 2+) ions is explored by integrated analysis of U L3-edge XANES and EXAFS. Density functional theory calculations indicate the energetically favorable UO2 2+ binding. Consequently, TANP with excellent adsorption kinetics presents a high uranium capture capacity (14.62 mg-U g-Ads-1) and a high adsorption rate (0.97 mg g-1 day-1) together with excellent selectivity and biofouling resistance. Life cycle assessment and cost analysis demonstrate that TANP has tremendous potential for application in industrial-scale uranium extraction from seawater.

Ligand-Assistant Iced Photocatalytic Reduction to Synthesize Atomically Dispersed Cu Implanted Metal-Organic Frameworks for Photo-Enhanced Uranium Extraction from Seawater.

Uranium extraction from natural seawater is one of the most promising routes to address the shortage of uranium resources. By combination of ligand complexation and photocatalytic reduction, porous framework-based photocatalysts have been widely applied to uranium enrichment. However, their practical applicability is limited by poor photocatalytic activity and low adsorption capacity. Herein, atomically dispersed Cu implanted UiO-66-NH2 (Cu SA@UiO-66-NH2 ) photocatalysts are prepared via ligand-assistant iced photocatalytic reduction route. N-Cu-N moiety acts as an effective electron acceptor to potentially facilitate charge transfer kinetics. By contrast, there exist Cu sub-nanometer clusters by the typical liquid phase photoreduction, resulting in a relatively low photocatalytic activity. Cu SA@UiO-66-NH2 adsorbents exhibit superior antibacterial ability and improved photoreduction conversion of the adsorbed U(VI) to insoluble U(IV), leading to a high uranium sorption capacity of 9.16 mg-U/g-Ads from natural seawater. This study provides new insight for enhancing uranium uptake by designing SA-mediated MOF photocatalysts.

Decorating Channel Walls in Metal-Organic Frameworks with Crown Ethers for Efficient and Selective Separation of Radioactive Strontium(II).

Nuclear accidents and the improper disposal of nuclear wastes have led to serious environmental radioactive pollutions. The rational design of adsorbents for the highly efficient separation of strontium(II) is essential in treating nuclear waste and recovering radioactive strontium resources. Metal-organic frameworks (MOFs) are potential materials for the separation of aqueous metal ions owing to their designable structure and tunable functionality. Herein, a novel 3D MOF material MOF-18Cr6, in which 1D channels are formed using 18-crown-6-ether-containing ligands as channel walls, is fabricated for strontium(II) separation. In contrast to traditional MOFs designed by grafting functional groups in the framework pores, MOF-18Cr6 possesses regular 18-crown-6-ether cavities on the channel walls, which not only can transport and intake strontium(II) via the channels, but also prevent blockage of the channels after the binding of strontium(II). Consequently, the functional sites are fully utilized to achieve a high strontium(II) removal rate of 99.73 % in simulated nuclear wastewater. This study fabricates a highly promising adsorbent for the separation of aqueous radioactive strontium(II), and more importantly, can provide a new strategy for the rational design of high-performance MOF adsorbents for separating target substances from complex aqueous environments.

Ultrasensitive Detection of Aqueous Uranyl Based on Uranyl-Triggered Protein Photocleavage.

The detection of environmental uranyl is attracting increasing attention. However, the available detection strategies mainly depend on the selective recognition of uranyl, which is subject to severe interference by coexisting metal ions. Herein, based on the unique uranyl-triggered photocleavage property, the protein BSA is labelled with fluorescent molecules that exhibit an aggregation-induced emission effect for uranyl detection. Uranyl-triggered photocleavage causes the separation of the fluorescent-molecule-labelled protein fragments, leading to attenuation of the emission fluorescence, which is used as a signal for uranyl detection. This detection strategy shows high selectivity for uranyl and an ultralow detection limit of 24 pM with a broad detection range covering five orders of magnitude. The detection method also shows high reliability and stability, making it a promising technique for practical applications in diverse environments.

In Situ Synthesis of Uranyl-Imprinted Nanocage for Selective Uranium Recovery from Seawater.

An adaptive coordination structure is vital for selective uranium extraction from seawater. By strategy of molecular imprinting, uranyl is introduced into a multivariate metal-organic framework (MOF) during the synthesis process to guide the in situ construction of proper nanocage structure for targeting uranyl binding. Except for the coordination between uranium with four oxygen from the materials, the axial oxygen of uranyl also forms hydrogen bonds with hydrogen from the phenolic hydroxyl group, which enhances the binding affinity of the material to uranyl. Attributing to the high binding affinity, the adsorbent shows high uranium binding selectivity to uranyl against not only the interfering metal ions, but also the carbonate group that coordinates with uranyl to form [UO2 (CO)3 ]4- in seawater. In natural seawater, the adsorbent realizes a high uranium adsorption capacity of 7.35 mg g-1 , together with an 18.38 times higher selectivity to vanadium.

Spidroin-Inspired, High-Strength, Loofah-Shaped Protein Fiber for Capturing Uranium from Seawater.

The unique three-dimensional structure of spidrion determines the outstanding mechanical properties of the spider silk fiber. Inspired by the similarity of the three-dimensional structure of superb-uranyl binding protein (SUP) to that of spidroin, a dual-SUP (DSUP) chimeric protein fiber with high tensile strength is designed. The DSUP hydrogel fiber exhibits a loofah-shape structure by the cross-interaction of the protein nanofiber. Full exposure of abundant functional uranyl-binding sites in the stretchable loofah-shape hydrogel protein fiber give the DSUP fiber a groundbreaking uranium extraction capacity of 17.45 mg g-1 with an ultrashort saturation time of 3 days in natural seawater. This work reports the design of an adsorbent with ultrahigh uranium extraction capacity and explores a strategy for fabricating artificial high-strength functional non-spidroin protein fiber.

A Bio-inspired Nano-pocket Spatial Structure for Targeting Uranyl Capture.

Biology has evolved excellent spatial structures for high-selectivity and high-affinity capture of heavy metals. Inspired by the spatial structure of the superb-uranyl binding protein SUP, we mimic the spatial structure of SUP in metal-organic frameworks (MOFs). The MOF UiO-66-3C4N fabricated by introducing 4-aminoisophthalic acid into UiO-66 shows high uranyl adsorption capacity both in simulated seawater and in natural seawater. In natural seawater, UiO-66-3C4N exhibits 17.03 times higher uranium extraction capacity than that of vanadium, indicating the high selectivity of the adsorbent. The EXAFS analysis and DFT calculation reveal that UiO-66-3C4N forms smaller nano-pocket for uranyl capture than that of SUP protein, which can both restrict the entrance of the other interfering ions with larger size and reinforce the binding by increasing the coordination interaction, and therefore qualify the nano-pocket with high affinity and high selectivity to uranyl.

Photoinduced Multiple Effects to Enhance Uranium Extraction from Natural Seawater by Black Phosphorus Nanosheets.

Based on the photoinduced photothermal, photoelectric, and photocatalytic effects of black phosphorus (BP) nanosheets, a BP-PAO fiber with enhanced uranium extraction capacity and high antibiofouling activity is fabricated by compositing BP nanosheets into polyacrylamidoxime (PAO). The photothermal effect increases the coordination interaction between UO2 2+ and the functional amidoxime group, and the photoelectric effect produces the surface positive electric field that exhibits electrostatic attraction to the negative [UO2 (CO3 )3 ]4- , which all increase the capacity for uranium adsorption. The photocatalytic effect endows the adsorbent with high antibiofouling activity by producing biotoxic reactive oxygen species. Owing to these three photoinduced effects, the photoinduced BP-PAO fiber shows a high uranium adsorption capacity of 11.76 mg g-1 , which is 1.50 times of the PAO fiber, in bacteria-containing natural seawater.

A Dual-Surface Amidoximated Halloysite Nanotube for High-Efficiency Economical Uranium Extraction from Seawater.

By chemical cross-linking the amidoxime group onto dual-surfaces of natural ore materials, namely halloysite nanotubes (HNTs), an efficient adsorbent, AO-HNTs, is developed. AO-HNTs show high uranium adsorption capacity of 456.24 mg g-1 in 32 ppm uranium-spiked simulated seawater. In natural seawater, AO-HNTs reach the high uranium extraction capacity of 9.01 mg g-1 after 30 days' field test. The dual-surface amidoximated hollow nanotubular AO-HNTs exhibit more coordination active sites for uranium adsorption, which is attributed to the high and fast uranium adsorption capacity. Because of the stable natural ore structure, AO-HNTs also show long service life. Benefiting from the low cost of HNTs, the cost for uranium extraction from seawater is close to the uranium price in the spot uranium market, suggesting that AO-HNTs could be used for economical extraction of uranium from the oceans.

Ultrafast and Highly Selective Uranium Extraction from Seawater by Hydrogel-like Spidroin-based Protein Fiber.

For the practical extraction of uranium from seawater, adsorbents with high adsorption capacity, fast equilibrium rate, high selectivity, and long service life are needed. Herein, a chimeric spidroin-based super uranyl-binding protein (SSUP) fiber was designed by fusing the gene of super uranyl-binding protein (SUP) with the gene of spidroin. SUP endowed the SSUP fiber with high affinity and selectivity to uranium, and spidroin gave the SSUP fiber with high mechanical strength and high reusability. The wet SSUP fiber is a water-rich hydrogel-like structure, which provided abundant hydrophilic intermolecular space for the entrance of uranyl ions, and could accelerate the rate for uranium adsorption. In seawater, the SSUP fiber achieved a breakthrough uranium extraction capacity of 12.33 mg g-1 with an ultrashort equilibration time of 3.5 days, suggesting that SSUP fiber might be a promising adsorbent for uranium extraction from the natural seawater.

Efficient and Selective Methane Borylation Through Pore Size Tuning of Hybrid Porous Organic-Polymer-Based Iridium Catalysts.

As a new energy source that could replace petroleum, the global reserves of methane hydrate (combustible ice) are estimated to be approximately 20 000 trillion cubic meters. A large amount of methane hydrate has been found under the seabed, but the transportation and storage of methane gas far from coastlines are technically unfeasible and expensive. The direct conversion of methane into value-added chemicals and liquid fuels is highly desirable but remains challenging. Herein, we prepare a series of iridium complexes based on porous polycarbazoles with high specific areas and good thermochemical stabilities. Through structure tuning we optimized their catalytic activities for the selective monoborylation of methane. One of these catalysts (CAL-3-Ir) can produce methyl boronic acid pinacol ester (CH3 Bpin) in 29 % yield in 9 h with a turnover frequency (TOF) of approximately 14 h-1 . Because its pore sizes favor monoborylated products, it has a high chemoselectivity for monoborylation (CH3 Bpin:CH2 (Bpin)2 =16:1).

Characterization of a novel phage infecting the pathogenic multidrug-resistant Bacillus cereus and functional analysis of its endolysin.

Bacillus cereus is widely distributed food-borne pathogenic bacterium. Due to the harmness to human hearth and the generation of multidrug-resistant B. cereus, it is urgent to develop novel antimicrobial agents. Phage and phage endolysin were taken as novel antimicrobial substance for their specific lytic activity against pathogenic bacteria. In this study, a Myoviridae family phage, designated as vB_BceM-HSE3, infecting the pathogenic multidrug-resistant B. cereus strain was isolated and characterized along with its endolysin. Phage vB_BceM-HSE3 can specially infect the B. cereus group strains, including B. cereus, B. anthracis, and B. thuringiensis, and exhibits high temperature and pH tolerance, which endow it with high potential for been used in controlling pathogenic B. cereus group strains. Genomic analysis reveals that vB_BceM-HSE3 is a novel phage and only shows extremely low genome similarity with available phage genome. Functional analysis of endolysin PlyHSE3 encoding by vB_BceM-HSE3 shows that PlyHSE3 exhibits broader lytic spectrum than the phage and can lyse all the tested B. cereus group strains as well as the tested pathogenic strain of P. aeruginosa. PlyHSE3 also shows broad temperature and pH tolerance, and can efficiently lyse B. cereus strain at temperature at 4 °C and higher than 45 °C, which indicating that PlyHSE3 might can be used in controlling food-borne B. cereus during both the cold storage of food and the stage after the heat treatment of food. The findings of this study enrich our understanding of phage diversity as well as providing resources for developing phage therapy.

Marangoni Effect-Driven Motion of Miniature Robots and Generation of Electricity on Water.

The well-known Marangoni effect perfectly supports the dynamic mechanism of organic solvent-swollen gels on water. On this basis, we report a series of energy conversion processes of concentrated droplets of polyvinylidene fluoride/dimethyl formamide (PVDF/DMF) that can transfer chemical-free energy to kinetic energy to rapidly rotate itself on water. This droplet (22.2 mg) is capable to offer kinetic energy of 0.099 µJ to propel an artificial paper rocket of 31.8 mg to move over 560 cm on water at an initial velocity of 7.9 cm s-1. As the droplet increases to 35.0 mg, a paper goldfish of 10.6 mg can be driven to swim longer at a higher initial velocity of 20 cm s-1. The kinetic energy of the droplet can be further converted to electrical energy through an electromagnetic generator, in which as a 0.5 MΩ resistor is loaded, the peak output reaches 6.5 mV that corresponds to the power density of 0.293 µW kg-1. We believe that this report would open up a promising avenue to exploit energies for applications in miniature robotics.

Characteristics and complete genome analysis of a novel jumbo phage infecting pathogenic Bacillus pumilus causing ginger rhizome rot disease.

Tailed phages with genomes larger than 200 kbp are classified as jumbo phage and exhibit extremely high diversity. In this study, a novel jumbo phage, vB_BpuM_BpSp, infecting pathogenic Bacillus pumilus, the cause of ginger rhizome rot disease, was isolated. Notable features of phage vB_BpuM_BpSp are the large phage capsid of 137 nm and baseplate-attached curly tail fibers. The genome of the phage is 255,569 bp in size with G+C content of 25.9 %, and it shows low similarity to known biological entities. The phage genome contains 318 predicted coding sequences. Among these predicted coding sequences, 26 genes responsible for nucleotide metabolism were found, and seven structural genes could be identified. The findings of this study provide new understanding of the genetic diversity of phages.

Construction of an environmental safe Bacillus thuringiensis engineered strain against Coleoptera.

Cloning of new toxic genes from Bacillus thuringiensis (Bt) and construction of Bt engineered strains are two key strategies for bio-control of coleopteran pests in agriculture and forestry. In this study, we cloned a new cry3Aa-type gene, cry3Aa8, from wild Bt strain YC-03 against coleopteran, and constructed a Bt engineered strain, ACE-38, containing insecticidal protein-encoding gene cry3Aa8. The engineered strain, with almost four times of Cry3Aa yield compared with strain YC-03, was an antibiotic marker-free strain. Though no selective pressure was presented in the medium, cry3Aa8 in the engineered strain ACE-38 remained stable. The yield of Cry3Aa by strain ACE-38 reached 2.09 mg/ml in the optimized fermentation medium. The activity of strain ACE-38 against Plagiodera versicolora was tested, and the LC50 of ACE-38 cultures in the optimized fermentation medium was 1.13 µl/ml. Strain ACE-38 is a non-antibiotic Bt engineered strain with high Chrysomelidae toxicity and exhibits good fermentation property. The modified indigenous site-specific recombination system constructed in this study might be useful for the construction of Bt engineered strains containing genes that cannot be expressed in the indigenous site-specific recombination system using plasmid pBMB1205R.

Effects of actin-like proteins encoded by two Bacillus pumilus phages on unstable lysogeny, revealed by genomic analysis.

We characterized two newly isolated myoviruses, Bp8p-C and Bp8p-T, infecting the ginger rhizome rot disease pathogen Bacillus pumilus GR8. The plaque of Bp8p-T exhibited a clear center with a turbid rim, suggesting that Bp8p-T could transform into latent phage. Lysogeny assays showed that both the two phages could form latent states, while Bp8p-T could form latent phage at a higher frequency and stability than Bp8p-C. The genomes of Bp8p-C and Bp8p-T were 151,417 and 151,419 bp, respectively; both encoded 212 putative proteins, and only differed by three nucleotides. Moreover, owing to this difference, Bp8p-C encoded a truncated, putative actin-like plasmid segregation protein Gp27-C. Functional analysis of protein Gp27 showed that Gp27-T encoded by Bp8p-T exhibited higher ATPase activity and assembly ability than Gp27-C. The results indicate that the difference in Gp27 affected the phage lysogenic ability. Structural proteome analysis of Bp8p-C virion resulted in the identification of 14 structural proteins, among which a pectin lyase-like protein, a putative poly-gamma-glutamate hydrolase, and three proteins with unknown function, were firstly identified as components of the phage virion. Both phages exhibited specific lytic ability to the host strain GR8. Bp8p-C showed better control effect on the pathogen in ginger rhizome slices than Bp8p-T, suggesting that Bp8p-C has a potential application in bio-control of ginger rhizome rot disease.

Genomic characteristics and comparative genomics analysis of Penicillium chrysogenum KF-25.

BACKGROUND: Penicillium chrysogenum has been used in producing penicillin and derived ß-lactam antibiotics for many years. Although the genome of the mutant strain P. chrysogenum Wisconsin 54-1255 has already been sequenced, the versatility and genetic diversity of this species still needs to be intensively studied. In this study, the genome of the wild-type P. chrysogenum strain KF-25, which has high activity against Ustilaginoidea virens, was sequenced and characterized. RESULTS: The genome of KF-25 was about 29.9 Mb in size and contained 9,804 putative open reading frames (orfs). Thirteen genes were predicted to encode two-component system proteins, of which six were putatively involved in osmolarity adaption. There were 33 putative secondary metabolism pathways and numerous genes that were essential in metabolite biosynthesis. Several P. chrysogenum virus untranslated region sequences were found in the KF-25 genome, suggesting that there might be a relationship between the virus and P. chrysogenum in evolution. Comparative genome analysis showed that the genomes of KF-25 and Wisconsin 54-1255 were highly similar, except that KF-25 was 2.3 Mb smaller. Three hundred and fifty-five KF-25 specific genes were found and the biological functions of the proteins encoded by these genes were mainly unknown (232, representing 65%), except for some orfs encoding proteins with predicted functions in transport, metabolism, and signal transduction. Numerous KF-25-specific genes were found to be associated with the pathogenicity and virulence of the strains, which were identical to those of wild-type P. chrysogenum NRRL 1951. CONCLUSION: Genome sequencing and comparative analysis are helpful in further understanding the biology, evolution, and environment adaption of P. chrysogenum, and provide a new tool for identifying further functional metabolites.

Genomic analysis of a phage and prophage from a Bacillus thuringiensis strain.

Bacteriophages have been found to be the most abundant and also potentially most diverse biological entities on Earth. In the present study, Bacillus phages were isolated rapidly and shown to have a high degree of diversity. The genomes of a newly isolated phage, phiCM3, and a prophage, proCM3, from the Bacillus thuringiensis strain YM-03 were sequenced and characterized. Comparative genome analysis showed that the phiCM3 genome is highly similar to the genomes of eight other Bacillus phages and seven of these phages were classified as the Wß group of phages. Analysis of the differential evolution of the genes in the Wß-group phages indicated that the genes encoding the antirepressor and tail fibre protein were more highly conserved than those encoding the major capsid protein, DNA replication protein, and RNA polymerase σ factor, which might have diverged to acquire mechanisms suitable for survival in different microbial hosts. Genome analysis of proCM3 revealed that proCM3 might be a defective phage because of mutations in the minor structural protein, and it was not inducible by mitomycin C treatment. The proCM3 genome was similar to those of two lytic Bacillus phages in sequence, but had a different genomic structure, composed of three regions in a different order. These data suggest that the three phages might have had a common ancestor and that genome rearrangement might have occurred during evolution. The findings of this study enrich our current knowledge of Bacillus phage diversity and evolution, especially for the Wß-group and TP21-L-like phages, and may help the development of practical applications of Bacillus phages.

Yeast-Raised Polyamidoxime Hydrogel Prepared by Ice Crystal Dispersion for Efficient Uranium Extraction from Seawater.

Uranium extraction from seawater has attracted worldwide attention due to the massive reserves of uranium. Due to the straightforward synthesis and strong affinity toward uranyl ions (UO2 2+), the amidoxime group shows promise for use in highly efficient uranium capture.  However, the low mass transfer efficiency within traditional amidoxime-based adsorbents severely limits the adsorption rate and the utilization of adsorption sites. In this work, a macroporous polyamidoxime (PAO) hydrogel is prepared by yeast-based biological foaming combined with ice crystal dispersion that effectively maintained the yeast activity. The yeast-raised PAO (Y-PAO) adsorbent has numerous bubble-like holes with an average pore diameter >100 µm. These macropores connected with the intrinsic micropores of PAO to construct efficient diffusion channels for UO2 2+ provided fast mass transporting channels, leading to the sufficient exposure of hidden binding sites. The maximum adsorption capacity of Y-PAO membrane reached 10.07 mg-U/g-ads, ≈1.54 times higher than that of the control sample. It took only eight days for Y-PAO to reach the saturation adsorption capacity of the control PAO (6.47 mg-U/g-ads, 28 days). Meanwhile, Y-PAO possessed excellent ion selectivity, good reusability, and low cost. Overall, the Y-PAO membrane is a highly promising adsorbent for use in industrial-scale uranium extraction from seawater.

Bacillus pumilus, a Novel Ginger Rhizome Rot Pathogen in China.

Ginger rhizome rot is a major factor limiting the yield and marketability of ginger in Shandong Province, China. In order to identify the pathogen causing ginger rhizome rot, evaluate its pathogenicity, and explore its pathogenesis, diseased ginger rhizomes and surrounding soils were collected. A gram-positive, spore-forming, rod-shaped bacterium, designated GR8, was frequently isolated from the ginger rhizome samples. The bacterium was identified as Bacillus pumilus based on physio-biochemical and molecular biology characteristics. Pathogenicity studies with GR8 showed that it could cause disease of the tested rhizomes slices and the entire rhizome when wounded but no disease occurred when the rhizome was not wounded. Preliminary pathogenicity studies demonstrated that cell-free cultures of GR8 could not cause any disease symptoms, whereas the bacterial suspensions caused severe symptoms. The pathology studies revealed that infection of GR8 could cause starch grains to shrink from normal size, and destroy the parenchyma cells by invading and propagating in them. This is the first report of B. pumilus causing ginger rhizome rot.