Interface Visualization of Bio-material Interaction Via Cryo-AEM Using the Biosynthesis of Iron-Based Nanoparticles as a Model.

Although interaction between organisms and nonorganisms is vital in environmental processes, it is difficult to characterize at nanoscale resolution. Biosynthesis incorporates intracellular and extracellular processes involving crucial interfacial functions and electron and substance transfer processes, especially on the inorganic-organic interface. This work chooses the biosynthesis of iron-based nanoparticles (nFe) as a model for biomaterial interaction and employs Cryo-AEM (i.e., S/TEM, EELS, and EDS analysis based on sample preparation with cryo-transfer holder system), combined with CV, Raman, XPS, and FTIR to reveal the inorganic-organic interface process. The inorganic-organic interactions in the biosynthesis of iron-based nanoparticles by Shewanella oneidensis MR-1 (M-nFe) were characterized by changes in electron cloud density, and the corresponding chemical shifts of Fe and C EELS edges confirm that M-nFe acquires electrons from MR-1 on the interface. Capturing intact filamentous-like, slightly curved, and bundled structure provides solid evidence of a "circuit channel" for electron transfer between organic and inorganic interface. CV results also confirm that adding M-nFe can enhance electron transfer from MR-1 to ferric ions. A mechanism for the synthesis of M-nFe with MR-1 based on intracellular and extracellular conditions under facultative anaerobic was visualized, providing a protocol for investigating the organic-inorganic interface.

Transcriptome analysis reveals a composite molecular map linked to unique seed oil profile of Neocinnamomum caudatum (Nees) Merr.

BACKGROUND: Neocinnamomum caudatum (Nees) Merr., a biodiesel tree species in the subtropical areas of South China, India and Burma, is distinctive from other species in Lauraceae family and its seed oil is rich in linoleic acid (18:2) and stearic acid (18:0). However, there is little genetic information about this species so far. In this study, a transcriptomic analysis on developing seeds of N. caudatum was conducted in an attempt to discern the molecular mechanisms involving the control of the fatty acid (FA) and triacylglycerol (TAG) biosynthesis. RESULTS: Transcriptome analysis revealed 239,703 unigenes with an average length of 436 bp and 137 putative biomarkers that are related to FA formation and TAG biosynthesis. The expression patterns of genes encoding ß-ketoacyl-acyl carrier protein synthase I (KASI), ß- ketoacyl-acyl carrier protein synthase II (KASII), stearoyl-ACP desaturase (SAD), fatty acid desaturase 2 (FAD2), fatty acid desaturase 8 (FAD8) and acyl-ACP thioesterase A/B (FATA/B) were further validated by qRT-PCR. These genes displayed a very similar expression pattern in two distinct assays. Moreover, sequence analysis of different FATBs from diverse plant species revealed that NcFATB is structurally different from its counterpart in other species in producing medium-chain saturated FAs. Concertedly, heterologous expression of NcFATB in E. coli BL21 (DE3) strain showed that this corresponding expressed protein, NcFATB, prefers long-chain saturated fatty acyl-ACP over medium-chain fatty acyl-ACP as substrate. CONCLUSIONS: Transcriptome analysis of developing N. caudatum seeds revealed a composite molecular map linked to the FA formation and oil biosynthesis in this biodiesel tree species. The substrate preference of NcFATB for long-chain saturated FAs is likely to contribute to its unique seed oil profile rich in stearic acid. Our findings demonstrate that in the tree species of Lauraceae family, the FATB enzymes producing long-chain FAs are structurally distinct from those producing medium-chain FAs, thereby suggesting that the FATB genes may serve as a biomarker for the classification of tree species of Lauraceae family.

Cyclodextrin modified green synthesized graphene oxide@iron nanoparticle composites for enhanced removal of oxytetracycline.

The presence of residual antibiotics will lead to potential environmental risks. Here cyclodextrins (CDs) were successfully used to modify graphene-based iron nanoparticles (GO@Fe NPs) to enhance the absorption of oxytetracycline hydrochloride (OTC). The removal of OTC decreased in the order: γCD-GO@Fe NPs > ßCD-GO@Fe NPs > αCD-GO@Fe NPs > GO@Fe NPs, with better performance than that of bare GO and Fe NPs. Characterization techniques were applied to better understand how CDs impact the structure of GO@Fe NPs and improve removal performance. Raman and X-ray diffraction analysis showed that GO acted as a carrier to support Fe NPs within the grafted cyclodextrin, where GO also participated in the removal process. Cyclodextrin modified GO@Fe NPs had relatively small particle sizes (15 nm), with a high surface area (61.7 m2 · g-1). X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy suggested that cyclodextrin acted as both a stabilizing and capping agent during green synthesis, which could protect the reactivity of Fe NPs and simultaneously reduce aggregation. A potential synthesis mechanism of cyclodextrins modified composites was also proposed, and subsequent wastewater testing indicated that γCD-GO@Fe NPs had high potential for practical applications.

Green reduction of graphene oxide using Bacillus sphaericus.

While chemical methods are often used to convert graphene oxide (GO) to reduced graphene oxide (RGO), chemical reduction is often environmentally unfriendly due to the high toxicity of many chemical reducing agents. To address this limitation, Bacillus sphaericus was used here for the green reduction of GO to RGO. Successful reduction was confirmed by various advanced characterization techniques including Ultraviolet-Visible (UV-vis), X-ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscope and Energy Dispersive Spectrometer (SEM-EDS). With a new peak attributable to RGO at 261 nm appearing in UV-vis and XRD spectra of the reduced product also developed a new peak at 2θ = 24.6° characteristic of RGO. Successful reduction was also supported by Raman spectroscopy which showed that the ratio of the intensity band (D band: G band) increased from 0.99 to 1.17. FTIR and XPS both confirmed that specific OH (3399 cm-1), CO (1734 cm-1) and COC (287 eV) bonds were reduced. Cyclic voltammograms (CVs) showed that the produced RGO exhibited good conductivity (changed from 0.8 to 1.1 mW·cm-2). This work developed a green and easy operated method of synthesizing RGO using microorganisms.

Fenton-oxidation of rifampicin via a green synthesized rGO@nFe/Pd nanocomposite.

Antibiotics are an emerging class of persistent contaminants that are now of major environmental concern because they pose potential risks to both environmental and human health. Here reduced graphene oxide composited with bimetallic iron/palladium nanoparticles (rGO@nFe/Pd) was synthesized via a green tea extract and used to remove a common antibiotic, rifampicin from aqueous solution. The innate physical rifampicin removal efficiency of the composite (79.9 %) was increased to 85.7 % when combined with Fenton-oxidation. The mechanism and the main factors controlling Fenton-oxidation of rifampicin by rGO@nFe/Pd were investigated. Oxidation followed a pseudo-second-order degradation kinetic model with an activation energy of 47.3 kJ mol-1. rGO@nFe/Pd were characterized by Brunauer-Emmett-Teller (BET), fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray energy spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-Ray powder diffraction (XRD), and zeta potential. Rifampicin degradation products observed by LC-UV, where subsequently confirmed to be mainly 5,6,9-trihydroxynaphtho [2,1-b] furan-1(2 H)-one, 5,6-dihydroxy-1-oxo-1,2-dihydronaphtho [2,1-b] furan-2-yl formate and (S)-5,6,9-trihydroxy-2-(3-methoxypropoxy)-2-methylnaphtho [2,1-b] furan-1(2 H)-one by LC-MS. Finally, the practical effectiveness of the composite material for antibiotic removal was demonstrated by the treatment of representative wastewaters, where rifampicin removal efficiencies of 80.4, 77.9 and 70.2 % were observed for river, aquaculture wastewater and domestic wastewater, respectively.

Mechanism and impact of synthesis conditions on the one-step green synthesis of hybrid RGO@Fe/Pd nanoparticles.

While a one-step green synthesis of a hybrid material composed of reduced graphene oxide and bimetallic Fe/Pd nanoparticles (RGO@Fe/Pd NPs) was previously successfully reported and evaluated for the removal of organic contaminants, the relationship between the formation of RGO@Fe/Pd and the resulting reactivity was unclear. In this paper the impact of the specific synthetic conditions on the reactivity of RGO@Fe/Pd was investigated in order to enhance the removal efficiency of antibiotics such as rifampicin. The hybrid material (RGO@Fe/Pd) successfully removed 96.1% of rifampicin compared to only 63.5 and 81.0% for Fe nanoparticles and RGO, respectively. The best synthetic conditions for the formation of RGO@Fe/Pd included GO/Fe = 1:1 and Fe/Pd = 100: 5. In addition, GC-MS and FTIR were used to identify the main reducing biomolecules in the green tea extract responsible for the one-step synthesis of RGO@Fe/Pd as Catechol, Caffeine, 1,3,5-Benzenetriol. The morphology, size and surface composition of RGO@Fe/Pd was characterized by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-Ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). These advanced characterization techniques suggested that during synthesis GO was initially converted to RGO, and thereafter Fe/Pd NPs (10-50 nm) were dispersed on RGO. Finally, a plausible formation mechanism for the one-step synthesis of the hybrid material was proposed.

Simultaneous removal of ammonia and phosphate using green synthesized iron oxide nanoparticles dispersed onto zeolite.

Since elevated levels of common nutrients, such as ammonia and phosphate, in natural water bodies (lakes and rivers) can lead to significant deterioration of pristine water ecosystems due to eutrophication, new and cost-effectiveness remediation strategies are urgently required. This work investigated the feasibility of using green synthesized iron oxide nanoparticles dispersed onto zeolite by eucalyptus leaf extracts (EL-MNP@zeolite), to simultaneously remove ammonia and phosphate from aqueous solutions. SEM and XRD both showed that EL-MNP@zeolite had better stability and dispersity than unsupported zeolite. At an initial concentration of 10 mg L-1 each for the two co-existing ions the synthesized material removed 43.3% of NH4+ and 99.8% of PO43-. Removal of co-existing NH4+-PO43- was impacted by the ratio of zeolite to EL-MNP, temperature, initial ion concentration and solution pH. Under optimium conditions the maximum adsorption capacity of EL-MNP@zeolite for NH4+ and PO43- was 3.47 and 38.91 mg g-1, respectively. For both ions' adsorption followed a pseudo-second-order kinetic reaction, confirming that the removal of ammonia and phosphate by EL-MNP@zeolite was via chemisorptions, where interaction between NH4+-PO43- and EL-MNP@zeolite may be through either electrostatic adsorption or ligand exchange. Overall these results indicated that EL-MNP@zeolite had significant potential as a nano-remediation strategy to simultaneously remove cationic ammonium and anionic phosphate from wastewaters.

Inhibitory Effect of MiR-449b on Cancer Cell Growth and Invasion through LGR4 in Non-Small-Cell Lung Carcinoma.

Non-small-cell lung carcinoma (NSCLC) is one of the most frequently diagnosed malignancies worldwide. Previous studies have shown that microRNA-449b (miR-449b) functions as a tumor suppressor in many cancers. However, the role of miR-449b in NSCLC is still unknown. In the present study, miR-449b was significantly downregulated in NSCLC samples and cell lines. Bioinformatics analysis revealed that 3'-UTR region of leucine rich repeat containing G protein-coupled receptor 4 (LGR4) mRNA had putative complementary sequences to miR-449b,which was further confirmed by the luciferase assay. Western blotting showed that restoration of miR-449b in NSCLC cells decreased the expression of LGR4. Interestingly, over-expression of miR-449b inhibited growth and invasion of NSCLC cells in vitro. Furthermore, ectopic expression of LGR4 reversed miR-449b-suppressed proliferation and invasion of NSCLC cells. Therefore, the data of the present study demonstrate that miR-449b inhibits tumor cell growth and invasion by targeting LGR4 in NSCLC.

miR-103 Functions as a Tumor Suppressor by Directly Targeting Programmed Cell Death 10 in NSCLC.

Non-small cell lung cancer (NSCLC) accounts for about 85% of all lung cancer cases. Absence of miR-103 has recently been identified to be associated with metastatic capacity of primary lung tumors. However, the exact role of miR-103 in NSCLC and the molecular mechanism are unclear. In the present study, we showed that miR-103 expression was reduced in NSCLC tissues and cells. miR-103 expression was negatively correlated with tumor size and stage. The overall survival was longer in patients with higher miR-103 level than in those with lower miR-103 expression. miR-103 inhibited cell proliferation in A549 cells, decreased tumor weight and volume, and prolonged survival of tumor-implanted nude mice. miR-103 increased apoptotic cell death in A549 cells. Furthermore, miR-103 decreased the invasion and migration abilities in A549 cells, as evidenced by Transwell and wound healing results. Downregulation of miR-103 significantly reduced the level of programmed cell death 10 (PDCD10). We found a significant decrease in the relative luciferase activity of the reporter gene in A549 cells cotransfected with the miR-103 mimic and pGL3-PDCD10 WT 3'-UTR, but not pGL3-PDCD10 mut 3'-UTR. We showed that overexpression of PDCD10 significantly inhibited miR-103-induced inhibition of cell proliferation, increased apoptosis, and decreased invasion and migration in A549 cells. Moreover, we found that PDCD10 expression was increased in NSCLC tissues and cells. PDCD10 expression was positively correlated with tumor size and stage. Overexpression of PDCD10 increased cell proliferation and inhibited apoptosis in A549 cells. The data demonstrated that dysregulation of the miR-103/PDCD10 signal may be a novel therapeutic target for the treatment of NSCLC.

Catalytic detoxification of mitoxantrone by graphitic carbon nitride (g-C3N4) supported Fe/Pd bimetallic nanoparticles.

The overuse of antibiotics and antitumor drugs has resulted in more and more extensive pollution of water bodies with organic drugs, causing detrimental ecological effects, which have attracted attention towards effective and sustainable methods for antibiotics and antitumor drug degradation. Here, the hybrid nanomaterial (g-C3N4@Fe/Pd) was synthesized and used to remove a kind of both an antibiotic and antitumor drug named mitoxantrone (MTX) with 92.0% removal efficiency, and the MTX removal capacity is 450 mg/g. After exposing to the hybrid material the MTX aqueous solution changed color from dark blue to lighter progressively, and LC-UV results of residual solutions show that a new peak at 3.0 min (MTX: 13.2 min) after removal by g-C3N4@Fe/Pd appears, with the simultaneous detection of intermediate products indicating that g-C3N4@Fe/Pd indeed degrades MTX. Detailed mass spectrometric analysis suggests that the nuclear mass ratio decreased from 445.2 (M+1H) to 126.0 (M+1H), 169.1 (M+1H), 239.2 (M+1H), 267.3 (M+1H), 285.2 (M+1H), 371.4 (M+1H) and 415.2 (M+1H), and the maximum proportion (5.63%) substance of all degradation products (126.0 (M+1H)) is 40-100 times less toxic than MTX. A mechanism for the removal and degradation of mitoxantrone was proposed. Besides, actual water experiments confirmed that the maximum removal capacity of MTX by g-C3N4@Fe/Pd is up to 492.4 mg/g (0.02 g/L, 10 ppm).