RESUMO
Cochliomycin G (1), a new 14-membered resorcylic acid lactone, together with six known analogues (2-7), was isolated from the culture broth of a marine-derived fungus Cochliobolus lunatus. The planar structure of 1 was established by extensive NMR spectroscopy, and the absolute configuration was elucidated by the combination of empirical rules, CD data, and 13C chemical shift calculations. Compound 1 exhibited potent antifouling activity against Chlorella vulgaris, Chaetoceros socialis, and Navicula exigua, with EC50 values of 1.09, 0.92, and 0.61 µg/mL, respectively.
Assuntos
Curvularia/química , Diatomáceas/efeitos dos fármacos , Lactonas/química , Lactonas/farmacologia , Incrustação Biológica/prevenção & controle , Chlorella vulgaris/efeitos dos fármacos , Dicroísmo Circular , Lactonas/isolamento & purificação , Espectroscopia de Ressonância Magnética , Microalgas/efeitos dos fármacos , Estrutura MolecularRESUMO
In 2015, we evaluated 221 patients with undifferentiated fever and tick bite or animal exposure in Xinyang, China, for Rickettsia infection. Three with mild disease were infected with Candidatus R. xinyangensis, which clustered with R. fournieri and R. vini in phylogenetic analyses. Field investigations suggest Haemaphysalis longicornis ticks might be involved in transmission.
Assuntos
Ixodidae , Rickettsia , Rickettsiose do Grupo da Febre Maculosa , Animais , China/epidemiologia , Humanos , Filogenia , Rickettsia/genética , Rickettsiose do Grupo da Febre Maculosa/diagnóstico , Rickettsiose do Grupo da Febre Maculosa/epidemiologiaRESUMO
Three new diketopiperazine alkaloids, including two oxepine-containing diketopiperazines, chrysopiperazines A and B (1 and 2), and one quinazoline-containing diketopiperazine, chrysopiperazine C (5), together with three known analogues (3, 4, and 6), were isolated from the gorgonian-derived Penicillium chrysogenum fungus. The relative and absolute configurations of C-3 and C-15 in 1 and 2, C-3 and C-14 in 5 were established by NOE modified Marfey's analysis and electronic circular dichroism (ECD) calculations. Particularly, the absolute configurations of C-19 in 1 and 3, which was very challenging to be identified due to the flexible conformation in a short aliphatic chain, were successfully determined by the vibrational circular dichroism (VCD) method, supplying with a reliable and optional method to define the absolute configurations. Additionally, this is the first report on oxepine-containing diketopiperazines from the genus Penicillium.
