A novel echinocandin MIG0310 with anticandida activity from newly isolated Fusarium sp. strain MS-R1.

AIM: To isolate and identify an anticandida compound from newly isolated Fusarium strain MS-R1 and characterization of its activity against standard and clinical strains of Candida. METHODS AND RESULTS: The fungal strain, Fusarium strain MS-R1, was isolated from soil. Molecular identification according to the internal transcribed spacer region of the rRNA gene sequence showed the strain to be strongly related to Fusarium brachygibbosum complex. Successive extractions of the active compound showed activity against Candida albicans, including clinical strains. Inhibition of a clinical strain of Candida tropicalis, but not Candida krusei and Candida glabrata, was also shown as tested by the broth microdilution assay. The compound was purified by liquid chromatography coupled with thin-layer chromatography and bioautography and characterized by nuclear magnetic resonance spectroscopy. It was confirmed to have the molecular formula C(48)H(66)O(18) and was identified as an echinocandin with a novel structure. CONCLUSION: A novel echinocandin-type antifungal metabolite, MIG0310, was isolated and characterized. This is a second echinocandin reported from a Fusarium species, indicating this genus to have wider range of echinocandin compounds. SIGNIFICANCE AND IMPACT OF THE STUDY: The new compound may lead to new anticandidal drugs, broadening the treatment opportunities for Candida species, including those that are resistant to the current antifungal drugs.

Evidence for cytochrome P-450 and P-450-mediated benzo(a)pyrene hydroxylation in the white rot fungus Phanerochaete chrysosporium.

The presence of cytochrome P-450 and P-450-mediated benzo(a)pyrene hydroxylase activity in both microsomal and soluble fractions of the white rot fungus Phanerochaete chrysosporium was shown. The reduced carbon monoxide difference spectrum showed maxima at 448-450 and 452-454 nm for microsomal and cytosolic fractions, respectively. Both P-450 fractions produced a Type I substrate binding spectrum on addition of benzo(a)pyrene. Activity for benzo(a)pyrene hydroxylation was NADPH dependent and inhibited by carbon monoxide. Km values for activity showed a difference between the cellular fractions with a Km of 89 microM for microsomal P-450 and 400 microM for cytosolic P-450. The Vmax values observed were 0.83 nmol min-1 (nmol microsomal P-450)-1 and 0.4 nmol min-1 (nmol cytosolic P-450)-1. The results indicate that P-450-mediated benzo(a)pyrene hydroxylase activity could play a role in xenobiotic transformation by this fungus beside the known ligninolytic exocellular enzymes.

Manganese-enhanced biotransformation of atrazine by the white rot fungus Pleurotus pulmonarius and its correlation with oxidation activity.

Manganese enhanced atrazine transformation by the fungus Pleurotus pulmonarius when added to a liquid culture medium at concentrations of up to 300 microM. Both N-dealkylated and propylhydroxylated metabolites accumulated in the culture medium, with the former accumulating to a greater extent than did the latter. Lipid peroxidation, oxygenase and peroxidase activities, and the cytochrome P-450 concentration increased. In addition, an increase in the spectral interactions between atrazine and components in the cell extract was observed. Antioxidants, mainly nordihydroguaiaretic acid, which inhibits lipoxygenase, peroxidase, and P-450 activities, and piperonyl butoxide, which inhibits P-450 activity, inhibited atrazine transformation by the mycelium. It is suggested that the stimulation of oxidative activity by Mn might be responsible for increasing the biotransformation of atrazine and for nonspecific transformations of other xenobiotic compounds.

Isolation and Characterization of a Novel Atrazine Metabolite Produced by the Fungus Pleurotus pulmonarius, 2-Chloro-4-Ethylamino-6-(1-Hydroxyisopropyl)Amino-1,3,5-Triazine.

The white rot fungus Pleurotus pulmonarius exhibited metabolism of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) in liquid culture, producing the dealkylated metabolites desethylatrazine, desisopropylatrazine, and desethyl-desisopropylatrazine. A fourth, unknown metabolite was also produced. It was isolated and was identified as 2-chloro-4-ethylamino-6-(1-hydroxyisopropyl)amino-1,3,5-triazine by gas chromatography-mass spectrometry, Fourier transformed infrared spectroscopy, and H nuclear magnetic resonance analysis. The structure of this metabolite was confirmed by chemical synthesis of the compound and comparison with the fungally produced metabolite.

Scanning Electron Microscope Studies of Interactions between Agaricus bisporus (Lang) Sing Hyphae and Bacteria in Casing Soil.

Relationships between the hyphae of Agaricus bisporus (Lang) Sing and bacteria from the mushroom bed casing layer were examined with a scanning electron microscope. Hyphae growing in the casing layer differed morphologically from compost-grown hyphae. Whereas the compost contained thin single hyphae surrounded by calcium oxalate crystals, the casing layer contained mainly wide hyphae or mycelial strands without crystals. The bacterial population in the hyphal environment consisted of several types, some attached to the hyphae with filamentlike structures. This attachment may be important in stimulation of pinhead initiation.

Engineering of heterologous cytochrome P450 in Acinetobacter sp.: application for pollutant degradation.

Many organisms do not contain the necessary biochemical armoury to carry out the initial oxidative attack of many pollutant chemicals. In the present study, Acinetobacter sp. strain BD413 has been genetically engineered to express the cytochrome P450 xenobiotic-metabolising enzyme CYP105D1 from Streptomyces griseus that has in its repertoire a diverse array of organic pollutants. Further, it is shown that the transformed Acinetobacter calcoaceticus strain BD413 can grow on pollutants unlike control bacteria not expressing cytochrome P450 and that was reflected in release of radiolabel with growth on radiolabelled chlortoluron. We show that cytochrome P450 can enhance the biodegrading repertoire of A. calcoaceticus and discuss the application of such results to bioremediation strategies.