Synthesis, crystal structure, interaction with BSA and antibacterial activity of La(III) and Sm(III) complexes with enrofloxacin.

Two new La(III) and Sm(III) complexes with enrofloxacin (HER, 1-cyclopropyl-7-(4-ethyl-1-piperazinyl)-6-fluoro-1,4-dihydro-4-oxo-3-quinoline carboxylic acid, C(19)H(21)FN(3)O(3)), [La(2)(ER)(6)(H(2)O)(2)]·14H(2)O(1) and [Sm(2)(ER)(6)(H(2)O)(2)]·14H(2)O(2) have been synthesized and characterized by elemental analysis, FT-IR, TG-DTG and X-ray single crystal diffraction. Both of the complexes are triclinic system with space group Pi. The structure of the complexes show that each rare earth atom in both complexes was nine-coordinated. Two of the enrofloxacin ions acted as tridentate chelate and bridging ligands, while the others as bidentate chelate ligands. The binding reaction between the complexes and bovine serum albumin (BSA) was studied by UV-vis absorption spectra and fluorescence spectroscopy. The results indicated that the two complexes had a quite strong ability to quench the fluorescence from BSA and the binding reaction was mainly a static quenching process. The binding constants K ( A )/(L·mol(-1)) were 1.46 × 10(5)(1) and 8.59 × 10(6)(2) and one binding site was formed. The synchronous spectroscopy suggested that tryptophan residues were placed in BSA. It was also found that the two complexes exhibited greater antimicrobial activity than enrofloxacin at given concentrations.

Degradation of Ferulic Acid by the Endophytic Fungus Colletotrichum gloeosporioides TMTM-13 Associated with Ostrya rehderiana Chun.

Biodegradation of ferulic acid, by an endophytic fungus Colletotrichum gloeosporioides TMTM-13 associated with Ostrya rehderiana Chun, was explored in this study. Ferulic acid was completely degraded by TMTM-13 as its initial concentration was lower than 400 mg L-1. Generally, the initial concentration of ferulic acid and fungal biomass of TMTM-13 kept synchronously growing up as the concentration was lower than 400 mg L-1. Fungal biomass reached a maximum of almost 1.177 g L-1 under concentrations of 400-450 mg L-1. HPLC-MS analysis indicated that ferulic acid ultimately degraded to vanillin, vanillic acid, acetovanillone, and dihydroconiferyl alcohol by TMTM-13. This study was the first report about an endophytic fungus associated with O. rehderiana Chun that has great potential for practical application in ferulic acid contaminated environments.

Antifungal activities of metabolites produced by a termite-associated Streptomyces canus BYB02.

Two main antifungal metabolites resistomycin and tetracenomycin D were isolated and purified from a termite-associated Streptomyces canus BYB02 by column chromatography. The structures of isolated compounds were determined on the basis of extensive spectroscopic analysis. Resistomycin possessed strong activities against mycelial growth of Valsa mali (IC(50) = 1.1 µg/mL) and Magnaporthe grisea (IC(50) = 3.8 µg/mL), which were comparable to those of referenced cycloheximide, with IC(50) values of 2.3 and 0.3 µg/mL, respectively. A further spore germination test showed that resistomycin exhibited potent reduction in spore germination for M. grisea , with an IC(50) value of 5.55 µg/mL. Finally, the in vivo antifungal activity experiment showed that resistomycin possessed significant preventive efficacy against rice blast, which was more potent than that of referenced carbendazim, with control efficacies of 66.8 and 58.7%, respectively. The present results suggest that resistomycin has potential to be used as a fungicide.