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Soil Particles and Phenanthrene Interact in Defining the Metabolic Profile of Pseudomonas putida G7: A Vibrational Spectroscopy Approach
摘要： In soil, organic matter and mineral particles (soil particles; SPs) strongly influence the bio-available fraction of organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), and the metabolic activity of bacteria. However, the effect of SPs as well as comparative approaches to discriminate the metabolic responses to PAHs from those to simple carbon sources are seldom considered in mineralization experiments, limiting our knowledge concerning the dynamics of contaminants in soil. In this study, the metabolic profile of a model PAH-degrading bacterium, Pseudomonas putida G7, grown in the absence and presence of different SPs (i.e., sand, clays and humic acids), using either phenanthrene or glucose as the sole carbon and energy source, was characterized using vibrational spectroscopy (i.e., FT-Raman and FT-IR spectroscopy) and multivariate classification analysis (i.e., PLS-DA). The different type of SPs specifically altered the metabolic profile of P. putida, especially in combination with phenanthrene. In comparison to the cells grown in the absence of SPs, sand induced no remarkable change in the metabolic profile of the cells, whereas clays and humic acids affected it the most, as revealed by the higher discriminative accuracy (R2, RMSEP and sensitivity) of the PLS-DA for those conditions. With respect to the carbon-source (phenanthrene vs. glucose), no effect on the metabolic profile was evident in the absence of SPs or in the presence of sand. On the other hand, with clays and humic acids, more pronounced spectral clusters between cells grown on glucose or on phenanthrene were evident, suggesting that these SPs modify the way cells access and metabolize PAHs. The macromolecular changes regarded mainly protein secondary structures (a shift from α-helices to β-sheets), amino acid levels, nucleic acid conformation and cell wall carbohydrates. Our results provide new interesting evidences that SPs specifically interact with PAHs in defining bacteria metabolic profiles and further emphasize the importance of studying the interaction of bacteria with their surrounding matrix to deeply understand PAHs degradation in soils.
关键词： phenanthrene,FTIR spectroscopy,soil particles,multivariate classification analysis,bacteria,metabolic profile,FT-Raman spectroscopy
更新于2025-11-14 15:16:37
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Photocatalytic removal of phenanthrene and algae by a novel Ca-Ag3PO4 composite under visible light: Reactivity and coexisting effect
摘要： In this study, the feasibility of a novel Ca-Ag3PO4 composite with visible light irradiation for the phenanthrene (PHE) degradation and algae inactivation in artificial seawater was firstly investigated. The experimental findings revealed that Ag3PO4 phase was sucessfully formed on the Ca-based material, and the presence of Ca-based material could effectively keep Ag3PO4 particles stable. An excellent performance on PHE degradation or algae inactivation was observed from Ca-Ag3PO4 composite under visible light irradiation. The degradation of PHE or inactivation of algae not only could be efficiently achieved in the single mode, but also could be successfully achieved in the coexisting mode. Above 96 % of PHE and algae were simultaneously removed within 12 h in the Ca-Ag3PO4/visible light system. It was further observed that the degradation of PHE and/or inactivation of algae increased with the increase of Ca-Ag3PO4 dosage. HO? was the primary radical responsible for PHE degradation, whereas HO? and Ag+ released from Ca-Ag3PO4 mainly contributed to the algae inactivation. A possible mechanism involving the catalytic removal of PHE and algae by Ca-Ag3PO4 under visible light irradiation was proposed. This study provides helpful guide for the simultaneous removal of various pollutants in real seawater.
关键词： Ag3PO4,Algae,Photocatalytic,Advanced oxidation processes (AOPs),Visible light,Phenanthrene (PHE)
更新于2025-09-23 15:23:52
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New cyclic and acyclic imidazole-based sensitizers for achieving highly efficient photoanodes for dye-sensitized solar cells by potential assisted method
摘要： A series of systematically tailored aryl acyclic (biphenyl, dye 1 and 2) and cyclic (phenanthrene, dye 3 and 4) and methyl-substituted (dye 5) imidazole derivatives were synthesized and characterized for dye-sensitized solar cells (DSSCs) application. Anisole ancillary donor was attached to -NH position in the imidazole center to obtain dye 2 and 4. Cyclic voltammetry and UV-visible studies of all the dyes indicate their suitability for DSSC application. Among the synthesized dyes, dye 4 having phenanthrene donor and anisole ancillary donor showed highest power conversion efficiency (PCE) of 7.16% (JSC = 13.07 mA/cm2, VOC = 0.831 V, FF = 0.659). Dye 2 displayed the highest electron lifetime in the conduction band of photoanode and hence the open circuit voltage of DSSC based on dye 2 was highest among the dyes studied (0.865 V). By using a novel potential assisted dye staining process, the dye loading on the photoanode is enhanced by 18% in 1h, which in turn enhanced the PCE to 8.10%.
关键词： DSSC,J-V characteristics,Imidazole,Phenanthrene,IPCE,Biphenyl
更新于2025-09-23 15:21:01
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Accumulation of 13C-labelled phenanthrene in phytoplankton and transfer to corals resolved using cavity ring-down spectroscopy
摘要： Polycyclic aromatic hydrocarbons (PAHs) are widespread pollutants in marine ecosystems including threatened and potentially sensitive coral reefs. Lower organisms such as phytoplankton, known to bioconcentrate PAHs, could serve as potential entry points for these chemicals into higher trophic levels. Here, we present a novel method using a 13C-labelled PAH and cavity ring-down spectroscopy (CRDS) to investigate accumulation, uptake rates and trophic transfer of PAHs in corals, which are key organisms to sustain biodiversity in tropical seas. We quantified the accumulation of 13C-phenanthrene in the marine microalga Dunaliella salina, and in the coral Acropora millepora after diffusive uptake from seawater or dietary uptake via labelled D. salina. Additionally, we monitored the photophysiological health of D. salina and A. millepora during phenanthrene exposure by pulse-amplitude modulation (PAM) fluorometry. Dose-dependent accumulation of 13C-phenanthrene in the microalga showed a mean bioconcentration factor (BCF) of 2590 ± 787 L kg?1 dry weight. Corals accumulated phenanthrene from both exposure routes. While uptake of 13C-phenanthrene in corals was faster through aqueous exposure than dietary exposure, passive diffusion showed larger variability between individuals and both routes resulted in accumulation of similar concentrations of phenanthrene. The 13C-PAH labelling and analysis by CRDS proved to be a highly sensitive method. The use of stable isotopic label eliminated additional toxicity and risks by radioactive isotopic-labelling, and CRDS reduced the analytical complexity of PAH (less biomass, no extraction, fast analysis). The simultaneous, precise quantification of both carbon content and 13C/12C ratio (δ13C) enabled accurate determination of 13C-phenanthrene accumulation and uptake rate. This is the first study to provide empirical evidence for accumulation of phenanthrene in a phytoplankton-coral food chain.
关键词： Phenanthrene,Bioaccumulation,PAHs,Phytoplankton,Stable isotopes,Corals
更新于2025-09-23 15:19:57
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Synthesis and Characterization of <i>N</i> , <i>N</i> ′-Bismesityl Phenanthrene-9,10-diimine and Imine–Nitrone
摘要： The sterically bulky compounds N,N′-bismesityl phenanthrene-9,10-diimine [1] and imine?nitrone [2] were synthesized. To the best of our knowledge, this is the first report of the synthesis of a bulky steric imine?nitrone accessed from the secondary ketimine using urea hydrogen peroxide over methyltrioxorhenium catalyst. Purified compounds were characterized using 1H and 13C NMR, high-resolution mass spectrometry, and infrared spectrometry. We report the first crystal structure of compound 1. Detailed IR bands of compounds 1 and 2 were assigned by comparing experimentally measured spectra to individually animated modes of quantum mechanically computed spectra. We believe these compounds may be of use as bidentate ligands in the synthesis of novel organometallic compounds. The asymmetric N and O coordination sites of compound 2 might impart interesting electronic effects to organometallic compounds compared to the symmetric N,N′-coordination sites of compound 1.
关键词： organometallic compounds,quantum mechanically computed spectra,N,N′-bismesityl phenanthrene-9,10-diimine,urea hydrogen peroxide,imine?nitrone,bidentate ligands,methyltrioxorhenium catalyst
更新于2025-09-04 15:30:14