Screening of Trichoderma isolates for their potential of biosorption of nickel and cadmium

Abstract Fourteen Trichoderma isolates were evaluated for their tolerance to two heavy metals, nickel and cadmium. Three isolates, MT-4, UBT-18, and IBT-I, showed high levels of nickel tolerance, whereas MT-4, UBT-18, and IBT-II showed better tolerance of cadmium than the other isolates. Under nickel stress, biomass production increased up to a Ni concentration of 60 ppm in all strains but then decreased as the concentrations of nickel were further increased. Among the nickel-tolerant isolates, UBT-18 produced significantly higher biomass upon exposure to nickel (up to 150 ppm); however, the minimum concentration of nickel required to inhibit 50% of growth (MIC50) was highest in IBT-I. Among the cadmium-tolerant isolates, IBT-II showed both maximum biomass production and a maximum MIC50 value in cadmium stress. As the biomass of the Trichoderma isolates increased, a higher percentage of nickel removal was observed up to a concentration of 40 ppm, followed by an increase in residual nickel and a decrease in biomass production at higher nickel concentrations in the medium. The increase in cadmium concentrations resulted in a decrease in biomass production and positively correlated with an increase in residual cadmium in the culture broth. Nickel and cadmium stress also influenced the sensitivity of the Trichoderma isolates to soil fungistasis. Isolates IBT-I and UBT-18 were most tolerant to fungistasis under nickel and cadmium stress, respectively.

Fungistasis of nanometer silvers synthesized by different methods on Candida al-bicans / 药学实践杂志

Objective To explore the in vitro fungistasis of nanometer silvers made by different methods on Candida al-bicans .Methods The minimal inhibitory concentrations (MICs) of Candida albicans strains stimulated to silver nanoparticles were determined by microdilution method .The combination effects of silver nanoparticles with fluconazole were determined by chess board check assay .Results The inhabitation effect of two kinds of silver nanoparticles were different on the growth of Candida albicans .Silver nanoparticles had a synergistic effect with fluconazole on Candida albicans .Conclusion The two kinds of silver nanoparticles had various antifungal activities in vitro and had a synergistic effect with fluconazole on Candida albicans .

Identification of Volatile Fungistatic Compounds by Spme-GC/MX / 微生物学通报

The composition of volatile compounds of soils and that of soil bacterial metabolites were identified by using the SPME-GC/MS method. Results showed that some compounds, trimethylamine, 3-methyl-2-pentanoe, dimethyl disulfide, methyl pyrazine, 2,5-dimethyl-pyrazine, benzaldehyde, N,N-dimethyloctylamine and nonadecane, subsisted commonly in soils and soil bacterial metabolites with strong fungistatic activity. These compounds may be the key antifungal factors in soil fungistasis, especially soil volatile fungistasis. Otherwise, the method used in this study was a good tool for further study of soil volatle fungistasis.