Identification and functional characterization of the xyloglucan endotransglucosylase/hydrolase 32 (AhXTH32) in peanut during aluminum-induced programmed cell death.

The toxicity of aluminum (Al) in acidic soil is a prevalent problem and causes reduced crop yields. In the plant response to Al toxicity, programmed cell death (PCD) appears to be an important mechanism. The plant cell wall of crop roots is the predominant site targeted by Al. Here, studies of the capacities of different cell wall constituents (pectin, hemicellulose 1 {HC1} and HC2) to adsorb Al indicated that HC1 has the greater ability to bind Al. The activity of xyloglucan endotransglucosylase (XET) was significantly inhibited by Al in the Al-tolerant peanut cultivar '99-1507' compared to that in 'ZH 2' (Al-sensitive). Results from qPCR analysis suggested that the suppression of XET activity by Al was transcriptionally regulated and that xyloglucan endotransglucosylase/hydrolase 32 (AhXTH32) was the major contributor to these changes. The overexpression of AhXTH32 in Arabidopsis strongly inhibited root growth with a loss of viability in root cells and the occurrence of typical hallmarks of PCD, while largely opposite effects were observed after xth32 suppression. AhXTH32 contributed to the modulation XET and xyloglucan endohydrolase (XEH) activity in vivo. Taken together, our results demonstrate that Al-tolerant peanut cultivar root tips cell walls bind Al predominantly in the HC1 fraction, which results in the inhibition of AhXTH32, with consequences to root growth, Al sensitivity, the occurrence of PCD and the XET/XEH activity ratio.

Water-stable metal organic framework-199@polyaniline with high-performance removal of copper II.

Metal organic frameworks (MOFs)-based adsorbents for copper ion (Cu2+) generally have the disadvantages of instability in water, low adsorption capacity, and selectivity. Aimed at such problems, we fabricated MOF-199 coated with polyaniline (MOF-199@PANI, core@shell) composite for specific adsorption of Cu2+ in water efficiently. Combined with the characterization by SEM, XRD, and FT-IR, the comprehensively excellent performance probably derived from porous structures of MOF-199, as well as the complexation between Cu2+ and the N atoms of imine moieties in PANI. In addition, the coating process by PANI perfectly protected the MOF skeleton. The isothermal data fitted well to Langmuir isotherm model, of which the calculated adsorption capacity reached 7831.34 mg/g. It was one or two orders of magnitude higher than some other new absorbent for Cu2+ including some carbon-based or organic adsorbents. On the basis of the optimization including pH value, temperature, and ratio of raw materials, the fabricated composite has realized the removal of the spiked Cu2+ in actual fresh water and industrial wastewater samples.

Chub movement is attracted by the collision sounds associated with spawning activities.

Cyprinids (carps, chubs and minnows) possess well-developed hearing and high sensitivity to sound pressure. The sensitive hearing may assist cyprinids with searching for food, territory defense, and mating behavior. Many paired fishes violently shake in sand and gravel while spawning in rivers. However, no study has examined the ecological importance of the collision sound made by the behavior. This study examined whether cohabitated chubs (Opsariichthys evolans and Zacco platypus) use the collision sound as a signal to locate spawning events so they can be a male satellite or egg eater. Three types of sounds (i.e., collision sound, music noise and ambient noise) were played with or without jerkbaits at the midstream of the Keelung River, Taiwan during the spawning season in 2018 and 2019. Generalized linear mixed models were then built to examine the effects of the sound types and the presence of jerkbaits on the number of individuals that the two chubs attracted. Results showed significantly different levels of attractiveness among the three sound types, with the collision sound attracting most fishes, including both females and males, followed by music noise and ambient noise. The presence of jerkbaits increased the number of fishes attracted, but the effect was only statistically marginally significant. These results suggest that the collision sound as an acoustic signal may be more important than a visual signal for the chubs to locate spawning events of other mating pairs, probably because of the longer transmission distance of the former. The present study demonstrates the ecological meanings of the collision sounds made in association with spawning activities of the chubs and implies that the native chub's spawning activities may be affected by the introduced Z. platypus. More studies on the interactions between these cohabitated chubs will benefit the conservation of native chubs.

Study on Cellulose Acetate Butyrate/Plasticizer Systems by Molecular Dynamics Simulation and Experimental Characterization.

Cellulose acetate butyrate (CAB) is a widely used binder in polymer bonded explosives (PBXs). However, the mechanical properties of PBXs bonded with CAB are usually very poor, which makes the charge edges prone to crack. In the current study, seven plasticizers, including bis (2,2-dinitro propyl) formal/acetal (BDNPF/A or A3, which is 1:1 mixture of the two components), azide-terminated glycidyl azide (GAPA), n-butyl-N-(2-nitroxy-ethyl) nitramine (Bu-NENA), ethylene glycol bis(azidoacetate) (EGBAA), diethylene glycol bis(azidoacetate) (DEGBAA), trimethylol nitromethane tris (azidoacetate) (TMNTA) and pentaerythritol tetrakis (azidoacetate) [PETKAA], were studied for the plasticization of CAB. Molecular dynamics simulation was conducted to distinguish the compatibilities between CAB and plasticizers and to predict the mechanical properties of CAB/plasticizer systems. Considering the solubility parameters, binding energies and intermolecular radical distribution functions of these CAB/plasticizer systems comprehensively, we found A3, Bu-NENA, DEGBAA and GAPA are compatible with CAB. The elastic moduli of CAB/plasticizer systems follow the order of CAB/Bu-NENA>CAB/A3>CAB/DEGBAA>CAB/GAPA, and their processing property is in the order of CAB/Bu-NENA>CAB/GAPA>CAB/A3>CAB/DEGBAA. Afterwards, all the systems were characterized by FT-IR, differential scanning calorimetry (DSC), differential thermogravimetric analysis (DTA) and tensile tests. The results suggest A3, GAPA and Bu-NENA are compatible with CAB. The tensile strengths and Young's moduli of these systems are in the order of CAB/A3>CAB/Bu-NENA>CAB/GAPA, while the strain at break of CAB/Bu-NENA is best, which are consistent with simulation results. Based on these results, it can be concluded that A3, Bu-NENA and GAPA are the most suitable plasticizers for CAB binder in improving mechanical and processing properties. Our work has provided a crucial guidance for the formulation design of PBXs with CAB binder.

Molecular Ordering and Performance of Ternary Nonfullerene Organic Solar Cells via Bar-Coating in Air with an Efficiency over 13.

An in situ spectroscopy ellipsometry technique is utilized to probe the molecular ordering sequences of PBDB-T-2F/IT-4F/COi8DFIC ternary photovoltaic blends fabricated by bar-coating in air. The time-resolved dynamics show that the primary electron acceptor IT-4F aggregates ahead of the secondary acceptor COi8DFIC in the bar-coated photoactive layer, although the latter has much stronger crystallization ability. Wetting coefficient analysis supports that COi8DFIC locates at the interface between the host components PBDB-T-2F and IT-4F. We demonstrate that the suitable degree of phase separation with the presence of 20 wt % COi8DFIC facilitates exciton dissociation and charge transfer, leading to a remarkable power conversion efficiency of 13.2% as well as excellent stability of ternary organic solar cells (OSCs), which is among the highest reported efficiency for OSCs that were fabricated by scalable solution-casting in ambient conditions.

TDI/TiO2 Hybrid Networks for Superhydrophobic Coatings with Superior UV Durability and Cation Adsorption Functionality.

Durability under UV illumination remains a big challenge of TiO2-based superhydrophobic coatings, with the photocatalytic effect causing degradation of low-surface-energy material over time, resulting in the surfaces losing their hydrophobicity. We report surfaces made from tolylene-2,4-diisocyanate (TDI)/TiO2 hybrid networks that demonstrate superhydrophobicity and superior UV durability. Structural and morphological studies reveal that the TDI/TiO2 hybrid networks are composed of TiO2 nanoparticles interconnected with TDI bridges and then encapsulated by a TDI layer. Through controlling the fraction of TDI in the synthesis process, the thickness of the TDI encapsulation layer around the TDI/TiO2 hybrid networks can be varied. When the weight ratio of TDI/TiO2 is 5:1, the superhydrophobicity of the hybrid network surface remains almost unchanged after a month of continuous UV illumination. This hybrid network surface can also clean methylene blue solution through the synergistic effects of cation adsorption and photocatalysis, holding promising potential for applications toward reducing cation pollutions in both liquid and air environments.

Hydrophobized SN38 to redox-hypersensitive nanorods for cancer therapy.

The clinical application of SN38 (7-ethyl-10-hydroxy-camptothecin) is severely restricted by its extremely low water solubility. Nanoaggregates formed by amphiphilic SN38 prodrugs have been widely used for the delivery of SN38. In this study, we used a hydrophobized SN38 prodrug, rather than a typical SN38 amphiphile, to construct rod-shaped nanoaggregates for efficient SN38 delivery. The hydrophobized SN38 was synthesized by conjugating SN38 with oleic acid using disulfanyl-ethyl carbonate as the linker. Interestingly, the resulting prodrug self-assembled into nanorods with high drug loading capacity (45%) and colloidal stability. Moreover, these nanorods displayed an impressively high redox-sensitivity to release 100% SN38 within 1 h in 10 mM DTT, versus 1% in phosphate buffer (pH 7.4). The efficient drug release resulted in an uncompromised in vitro cytotoxicity, which was comparable to free SN38 and nearly 93-fold more potent than CPT-11. Most importantly, these novel prodrug nanoaggregates exhibited potent antitumor activity in the CT26 colorectal cancer xenograft. The nanoaggregates of such redox-hypersensitive hydrophobized SN38 represent an effective alternative strategy for developing novel SN38 nanomedicines.

Utilizing a Pyrazine-Containing Aggregation-Induced Emission Luminogen as an Efficient Photosensitizer for Imaging-Guided Two-Photon Photodynamic Therapy.

The development of novel photosensitizers with aggregation-induced emission (AIE) characteristics has aroused tremendous interest, because it could combine efficient bioimaging with precise photodynamic therapy, which would thus dramatically promote applications in biomedical treatment. Among various AIE luminogens (AIEgens), heterocycle-containing molecules are highly promising for this usage because of their high photostability and tunable electronic properties. In this work, a pyrazine-containing AIEgen with a dicyanopyrazine moiety as an electron acceptor and a triphenylamine unit as an electron donor was chosen for study. The V-shaped donor-π-acceptor-π-donor structure of the AIEgen endowed its nanoparticles with excellent nonlinear optical properties for two-photon cell imaging under near-infrared laser excitation. Also, under the same excitation, the nanoparticles could produce reactive oxygen species and further kill the cells efficiently and accurately. The present work thus presents a pyrazine-containing AIEgen as a new photosensitizer for imaging-guided two-photon photodynamic therapy and gives more opportunities for deep-tissue treatment of cancer in future research.

Fluorescence resonance energy transfer (FRET) based nanoparticles composed of AIE luminogens and NIR dyes with enhanced three-photon near-infrared emission for in vivo brain angiography.

Near-infrared (NIR) fluorescence is very important for high-contrast biological imaging of high-scattering tissues such as brain tissue. Unfortunately, commercial NIR dyes are excited usually by visible light, and their multi-photon absorption (MPA) cross-sections are small. Here, we design new co-encapsulated NIR nanoparticles (NPs) with a large three-photon (3PA) absorption cross-section. A form of aggregation-induced emission (AIE) luminogen (AIEgen), 2,3-bis(4'-(diphenylamino)-[1,1'-biphenyl]-4-yl) fumaronitrile (TPATCN), is introduced as the donor, and a form of NIR dye, silicon 2,3-naphthalocyanine bis-(trihexylsilyloxide) (NIR775), is adopted as the acceptor. Under the excitation of a 1550 nm fs laser, TPATCN-NIR775 NPs demonstrated a bright three-photon fluorescence centered at 785 nm. The energy transfer efficiency of the TPATCN-NIR775 NPs was calculated to be as high as 90%, which could be attributed to the good spectral overlap between the emission of TPATCN and the absorption of NIR775. By injection with TPATCN-NIR775 NPs, a vivid 3D reconstruction of mouse brain vasculature was obtained with even small blood vessels clearly visualized. The design strategy used for the co-encapsulated AIE-NIR NPs would be helpful in synthesizing more NIR probes for deep-tissue biological imaging in the future.

Aggregation-Induced Emission Luminogen with Deep-Red Emission for Through-Skull Three-Photon Fluorescence Imaging of Mouse.

Imaging the brain with high integrity is of great importance to neuroscience and related applications. X-ray computed tomography (CT) and magnetic resonance imaging (MRI) are two clinically used modalities for deep-penetration brain imaging. However, their spatial resolution is quite limited. Two-photon fluorescence microscopic (2PFM) imaging with its femtosecond (fs) excitation wavelength in the traditional near-infrared (NIR) region (700-1000 nm) is able to realize deep-tissue and high-resolution brain imaging. However, it requires craniotomy and cranial window or skull-thinning techniques due to photon scattering of the excitation light. Herein, based on a type of aggregation-induced emission luminogen (AIEgen) DCDPP-2TPA with a large three-photon absorption (3PA) cross section at 1550 nm and deep-red emission, we realized through-skull three-photon fluorescence microscopic (3PFM) imaging of mouse cerebral vasculature without craniotomy and skull-thinning. Reduced photon scattering of a 1550 nm fs excitation laser allowed it to effectively penetrate the skull and tightly focus onto DCDPP-2TPA nanoparticles (NPs) in the cerebral vasculature, generating bright three-photon fluorescence (3PF) signals. In vivo 3PF images of the cerebral vasculature at various vertical depths were obtained, and a vivid 3D reconstruction of the vascular architecture beneath the skull was built. As deep as 300 µm beneath the skull, small blood vessels of 2.4 µm could still be recognized.

Bright AIE Nanoparticles with F127 Encapsulation for Deep-Tissue Three-Photon Intravital Brain Angiography.

Deep-tissue imaging is of great significance to biological applications. In this paper, a deep-red emissive luminogen 2,3-bis(4'-(diphenylamino)-[1,1'-biphenyl]-4-yl) fumaronitrile (TPATCN) with aggregation-induced emission (AIE) feature is prepared. TPATCN molecules were then encapsulated within a polymeric matrix of Pluronic F-127 to form nanoparticles (NPs). TPATCN NPs exhibit bright three-photon fluorescence (3PF) in deep-red region, together with high chemical stability, good photostability, and biocompatibility. They are further utilized for in vivo 3PF imaging of the brain vasculature of mice, under the excitation of a 1550 nm femtosecond laser. A vivid 3D reconstruction of the brain vasculature is then built with a penetration depth of 875 µm, which is the largest in ever reported 3PF imaging based on AIE NPs. After that, by collecting both of the 3PF and third-harmonic generation signals, multichannel nonlinear optical imaging of the brain blood vessels is further realized. These results will be helpful to study the structures and functions of the brain in the future.

Nitric Oxide Inhibits Al-Induced Programmed Cell Death in Root Tips of Peanut (Arachis hypogaea L.) by Affecting Physiological Properties of Antioxidants Systems and Cell Wall.

It has been reported that nitric oxide (NO) is a negative regulator of aluminum (Al)-induced programmed cell death (PCD) in peanut root tips. However, the inhibiting mechanism of NO on Al-induced PCD is unclear. In order to investigate the mechanism by which NO inhibits Al-induced PCD, the effects of co-treatment Al with the exogenous NO donor or the NO-specific scavenger on peanut root tips, the physiological properties of antioxidants systems and cell wall (CW) in root tip cells of NO inhibiting Al-induced PCD were studied with two peanut cultivars. The results showed that Al exposure induced endogenous NO accumulation, and endogenous NO burst increased antioxidant enzyme activity in response to Al stress. The addition of NO donor sodium nitroprusside (SNP) relieved Al-induced root elongation inhibition, cell death and Al adsorption in CW, as well as oxidative damage and ROS accumulation. Furthermore, co-treatment with the exogenous NO donor decreased MDA content, LOX activity and pectin methylesterase (PME) activity, increased xyloglucan endotransglucosylase (XET) activity and relative expression of the xyloglucan endotransglucosylase/hydrolase (XTH-32) gene. Taken together, exogenous NO alleviated Al-induced PCD by inhibiting Al adsorption in CW, enhancing antioxidant defense and reducing peroxidation of membrane lipids, alleviating the inhibition of Al on root elongation by maintaining the extensibility of CW, decreasing PME activity, and increasing XET activity and relative XTH-32 expression of CW.

Biocompatible aggregation-induced emission nanoparticles with red emission for in vivo three-photon brain vascular imaging.

Three-photon luminescence (3PL) imaging with near-infrared (NIR) excitation is quite promising for its deep penetration, high resolution, and good signal-to-noise ratio (SNR). In this report, a type of red emissive fluorophore TPEPT with aggregation-induced emission (AIE) properties was synthesized, and it was found to possess a large three-photon absorption (3PA) cross-section of 6.33 × 10-78 cm6 s2 under 1550 nm femtosecond laser excitation. TPEPT was then encapsulated with mPEG5000-DSPE to form AIE nanoparticles, and the chemical stability, optical properties and toxicity were studied afterwards. TPEPT nanoparticles were then applied for 3PL in vivo vascular imaging of mouse brain under 1550 nm fs laser excitation, and a fine three-dimensional (3D) reconstruction with a depth of 500 µm was achieved.

Red emissive AIE nanodots with high two-photon absorption efficiency at 1040 nm for deep-tissue in vivo imaging.

Deep-tissue penetration is highly required in in vivo optical bioimaging. We synthesized a type of red emissive fluorophore BT with aggregation-induced emission (AIE) property. BT molecules were then encapsulated with amphiphilic polymers to form nanodots, and a large two-photon absorption (2PA) cross-section of 2.9 × 10(6) GM at 1040 nm was observed from each BT nanodot, which was much larger than those at the wavelengths of 770 to 860 nm. In addition, 1040 nm light was found to have better penetration and focusing capability than 800 nm light in biological tissue, according to the Monte Carlo simulation. The toxicity and tissue distribution of BT nanodots were studied, and they were found to have good biocompatibility. BT nanodots were then utilized for in vivo imaging of mouse ear and brain, and an imaging depth of 700 µm was obtained with the femtosecond (fs) excitation of 1040 nm. The red emissive AIE nanodots with high 2PA efficiency at 1040 nm would be useful for deep-tissue functional bioimaging in the future.

Using AIE Luminogen for Long-term and Low-background Three-Photon Microscopic Functional Bioimaging.

Fluorescent probes are one of the most popularly used bioimaging markers to monitor metabolic processes of living cells. However, long-term light excitation always leads to photobleaching of fluorescent probes, unavoidable autofluorescence as well as photodamage of cells. To overcome these limitations, we synthesized a type of photostable luminogen named TPE-TPP with an aggregation induced emission (AIE) characteristic, and achieved its three-photon imaging with femtosecond laser excitation of 1020 nm. By using TPE-TPP as fluorescent probes, three-photon microscopy under 1020 nm excitation showed little photo-damage, as well as low autofluorescence to HeLa cells. Due to the AIE effect, the TPE-TPP nanoaggregates uptaken by cells were resistant to photobleaching under three-photon excitation for an extended period of time. Furthermore, we demonstrated that for the present TPE-TPP AIE the three-photon microscopy (with 1020 nm excitation) had a better signal to noise ratio than the two-photon microscopy (with 810 nm excitation) in tissue imaging.

Recycling flue gas desulphurization (FGD) gypsum for removal of Pb(II) and Cd(II) from wastewater.

The present study aims to verify the feasibility of directly reusing the flue gas desulphurization (FGD) gypsum generated from coal-fired power plants to adsorptively remove Pb(II) and Cd(II) from wastewater. The Toxicity Characteristic Leaching Procedure (TCLP) test was conducted to evaluate the leachability of toxic heavy metals from FGD gypsum. The adsorption behaviors of FGD gypsum for Pb(II) and Cd(II) such as pH impact, sorption kinetics, sorption isotherms and sorption thermodynamics were studied in a series of batch experiments. The pH studies indicated that the adsorption of Pb(II) and Cd(II) had their best adsorption amounts both at the pH values from 5.0 to 7.0. The kinetic analysis displayed that the adsorption processes both followed the pseudo-second order model well, and the FGD gypsum provided a higher sorption rate for Pb(II). Equilibrium studies showed that the adsorption of Pb(II) and Cd(II) could be properly described by Langmuir isotherms model, and the predicted maximum adsorption capacities were even greater than some specially prepared adsorbents. The thermodynamic investigation confirmed that the removal of Pb(II) and Cd(II) from aqueous medium could carry out spontaneously, and the higher temperature favored the processes. The instrument analysis techniques were also employed to deeply understand the mechanism involved in Pb(II) and Cd(II) removal by FGD gypsum. Overall, good sorption performance together with cost-effective characteristic makes FGD gypsum potentially attractive material for the Pb(II) and Cd(II) removal in industrial wastewater.

Photosensitizer encapsulated organically modified silica nanoparticles for direct two-photon photodynamic therapy and in vivo functional imaging.

Nanoparticle-assisted two-photon imaging and near infrared (NIR) imaging are two important technologies in biophotonics research. In the present paper, organically modified silica (ORMOSIL) nanoparticles encapsulated with either PpIX (protoporphyrin IX) photosensitizers or IR-820 NIR fluorophores were synthesized and optically characterized. Using the former ORMOSIL nanoparticles, we showed: (i) direct excitation of the fluorescence of PpIX through its efficient two-photon absorption in the intracellular environment of tumor cells, and (ii) cytotoxicity towards tumor cells by PpIX under two-photon irradiation. The latter ORMOSIL nanoparticles can be used as efficient NIR fluorescent contrast agents for various types in vivo animal imaging. We applied IR-820 doped ORMOSIL nanoparticles in in vivo brain imaging of mice. We also demonstrated the applications of them to sentinel lymph node (SLN) mapping of mice. Finally, we showed that the nanoprobes could target the subcutaneously xenografted tumor of a mouse for long time observations. ORMOSIL nanoparticles have great potentials for disease diagnosis and clinical therapies.

[SiRNA targeting ICP4 attenuates HSV-1 replication].

HSV-1, a neurotropic virus, always leads to severe nervous symptoms. It is hard to completely eradicate the latent viruses after conventional therapy so that recurrence is inevitable. ICP is a key regulator for HSV replication and transcription that determines the cytolytic infection or latent state. In search of new anti-virus strategy targeting HSV-1ICP4, two pairs of siRNA were designed, and a recombinant eukaryotic lentiviral expression plasmid pLKO-puro(r)-hU6-siRNA was constructed. Vero cells were transfected with the designed siRNAs by Lipofectamine 2000 and four stable monoclonal cell lines were established by puromycin screening method. The ICP4 expression at mRNA level was detected with real-time PCR, and the HSV-1 replication was measured with TCID50 assay. SiRNA was shown as an effective way to inhibit the expression of ICP4 in monoclonal cell lines. Meanwhile, HSV-1 replication was significantly inhibited when ICP4 was shut down by siRNA. We conclude that siRNA targeting ICP4 attenuates HSV-1 replication. Further more, multi-site siRNAs show stronger inhibitory effect on viral replication, which may be an effective and feasible approach for biological anti-viral drugs.

Multilayered polyelectrolyte-coated gold nanorods as multifunctional optical contrast agents for cancer cell imaging.

We report the application of multilayered polyelectrolyte-coated gold nanorods (GNRs) as multifunctional optical contrast agents for cancer cell imaging. The surface modification of GNRs improves their chemical stability and facilitates them to be taken up by cancer cells through electrostatic interaction. The unique longitudinal surface plasmon resonance property of GNRs makes them suitable as both "scattering contrast agents" and "Raman contrast agents". In our experiments, the staining of GNRs in cells was further confirmed by dark field microscopy and Raman microscopy. Our experiment results indicated that GNRs have great potential as multifunctional "optical contrast agents" for future in vivo animal imaging.