Doping of nitrogen into MnO2 is employed as an efficient catalyst for the catalytic oxidation of HMF to DFF under an oxygen atmosphere.

Class II fructose-1,6-bisphosphate aldolases (FBA-II) are attractive new targets for the discovery of drugs to combat invasive fungal infection, because they are absent in animals and higher plants. Although several FBA-II inhibitors have been reported, none of these inhibitors exhibit antifungal effect so far. In this study, several novel inhibitors of FBA-II from C. albicans (Ca-FBA-II) with potent antifungal effects were rationally designed by jointly using a specific protocols of molecular docking-based virtual screening, accurate binding-conformation evaluation strategy, synthesis and enzymatic assays. The enzymatic assays reveal that the compounds 3c, 3e-g, 3j and 3k exhibit high inhibitory activity against Ca-FBA-II (IC < 10 μM), and the most potential inhibitor is 3g, with IC value of 2.7 μM. Importantly, the compounds 3f, 3g, and 3l possess not only high inhibitions against Ca-FBA-II, but also moderate antifungal activities against C. glabrata (MIC = 4-64 μg/mL). The compounds 3g, 3l, and 3k in combination with fluconazole (8 μg/mL) displayed significantly synergistic antifungal activities (MIC < 0.0625 μg/mL) against resistant Candida strains, which are resistant to azoles drugs. The probable binding modes between 3g and the active site of Ca-FBA-II have been proposed by using the DOX (docking, ONIOM, and XO) strategy. To our knowledge, no FBA-II inhibitors with antifungal activities against wild type and resistant strains from Candida were reported previously. The positive results suggest that the strategy adopted in this study are a promising method for the discovery of novel drugs against azole-resistant fungal pathogens in the future.

Understanding the biomolecular interactions in a specific organelle has been a long‐standing challenge because it requires super‐resolution imaging to resolve the spatial locations and dynamic interactions of multiple biomacromolecules. Two key difficulties are the scarcity of suitable probes for super‐resolution nanoscopy and the complications that arise from the use of multiple probes. Herein, we report a quinolinium derivative probe that is selectively enriched in mitochondria and switches on in three different fluorescence modes in response to hydrogen peroxide (H2O2), proteins, and nucleic acids, enabling the visualization of mitochondrial nucleoprotein dynamics. STED nanoscopy reveals that the proteins localize at mitochondrial cristae and largely fuse with nucleic acids to form nucleoproteins, whereas increasing H2O2 level leads to disassociation of nucleic acid–protein complexes.

Cyanobacteria class II fructose-1,6-bisphoshate aldolase (Cy-FBA-II) and cyanobacteria fructose-1,6-bisphosphatase (Cy-FBPase) are two neighboring key regulatory enzymes in the Calvin cycle of the cyanobacteria photosynthesis system. Each of them might be taken as a potential target for designing novel inhibitors to chemically control harmful algal blooms (HABs). In the present paper, a series of novel inhibitors were rationally designed, synthesized, and optimized based upon the structural and interactional information of both Cy-FBA-II and Cy-FBPase, and their inhibitory activities were examined in vitro and in vivo. The experimental results showed that compounds L19e-L19g exhibited moderate inhibitory activities (IC50 = 28.1-103.2 μM) against both Cy-FBA-II and Cy-FBPase; compounds L19a-L19d, L19h, L20a-L20d exhibited high Cy-FBA-II inhibitory activities (IC50 = 2.3-16.9 μM) and moderate Cy-FBPase inhibitory activities (IC50 = 31.5-141.2 μM); however, compounds L20e-L20h could potently inhibit both Cy-FBA-II and Cy-FBPase with IC50 values less than 30 μM, which demonstrated more or less dual-target inhibitor's feature. Moreover, most of them exhibited potent algicide activity (EC50 = 0.8-22.3 ppm) against cyanobacteria Synechocystis sp. PCC 6803.

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In the present study, the electronic energy transfer pathways in trimeric and hexameric aggregation state of cyanobacteria C-phycocyanin (C-PC) were investigated in term of the Förster theory. The corresponding excited states and transition dipole moments of phycocyanobilins (PCBs) located into C-PC were examined by model chemistry in gas phase at time-dependent density functional theory (TDDFT), configuration interaction-singles (CIS), and Zerner's intermediate neglect of differential overlap (ZINDO) levels, respectively. Then, the long-range pigment-protein interactions were approximately taken into account by using polarizable continuum model (PCM) at TDDFT level to estimate the influence of protein environment on the preceding calculated physical quantities. The influence of the short-range interaction caused by aspartate residue nearby PCBs was examined as well. Only when the protonation of PCBs and its long- and short-range interactions were properly taken into account, the calculated energy transfer rates (1/K) in the framework of Förster model at TDDFT/B3LYP/6-31+G* level were in good agreement with the experimental results of C-PC monomer and trimer. Furthermore, the present calculated results suggested that the energy transfer pathway in C-PC monomer is predominant from β-155 to β-84 (1/K = 13.4 ps), however, from α-84 of one monomer to β-84 (1/K = 0.3-0.4 ps) in a neighbor monomer in C-PC trimer. In C-PC hexamer, an additional energy flow was predicted to be from β-155 (or α-84) in top trimer to adjacent β-155 (or α-84) (1/K = 0.5-2.7 ps) in bottom trimer.

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