ABSTRACT
Three new macrocyclic trichothecenes possessing rare 6'-ketal moieties, roridoxins A-C (1-3), and five known compounds (4-8) were isolated from the insect-associated fungus Myrothecium roridum. Their structures were confirmed by a combination of NMR and HRESIMS data, while their absolute configurations were unambiguously determined by single-crystal X-ray analysis and electronic circular dichroism experiments. Trichothecenes 1 and 3 showed potent antifungal activities against four strains of phytopathogenic fungi. In addition, 1, 3, 5, and 6 were found to significantly inhibit the cell growth of Candida albicans with minimal inhibitory concentration values from 8.8 to 18.5 µg/mL. Moreover, they were able to inhibit the biofilm formation of C. albicans better than the positive control.
Subject(s)
Antifungal Agents/chemistry , Antifungal Agents/pharmacology , Hypocreales/chemistry , Insecta/microbiology , Trichothecenes/chemistry , Trichothecenes/pharmacology , Animals , Antifungal Agents/metabolism , Candida albicans/drug effects , Candida albicans/growth & development , Hypocreales/isolation & purification , Hypocreales/metabolism , Microbial Sensitivity Tests , Molecular Structure , Trichothecenes/metabolismABSTRACT
A greenhouse study on the effects of soil covering on pepper (Capsicum anmuum L.) water use efficiency and soil nitrate and available phosphorus contents showed that straw mulch + plastic film mulch could get the highest pepper yield water use efficiency (33.04 kg . m(-3)) and economic water use efficiency (50.22 yuan . m(-3)), followed by plastic film mulch, with the two parameters being 18.81 kg . m(-3) and 28.57 yuan . m(-3), respectively. Significant differences of nitrate N content in 0-20 cm soil layer were observed among different treatments. The control had the highest nitrate N content (50.33 mg . kg(-1)), followed by straw mulch (31.98 mg . kg(-1)) and straw + plastic film mulch (31.96 mg . kg(-1)), and plastic film mulch and applying water preserving agent. Compared with the control, soil covering could increase the nitrate N use efficiency of pepper, and decrease the accumulation of nitrate N in plough layer. In 0-20 cm soil layer, treatment plastic film mulch had the lowest available phosphorus content (0.72 mg . kg(-3)), and the second (0. 92 mg . kg(-1)) was the treatment straw + plastic film mulch. Treatments straw + plastic film mulch and plastic film mulch could increase pepper fruit yield and fertilizer use efficiency, and decrease fertilizer loss.
