Metabolism of Bismuth Subsalicylate and Intracellular Accumulation of Bismuth by Fusarium sp. Strain BI

Abstract

Enrichment cultures were conducted using bismuth subsalicylate as the sole source of carbon and activated sludge as the inoculum. A pure culture was obtained and identified as a Fusarium sp. based on spore morphology and partial sequences of 18S rRNA, translation elongation factor 1-␣, and ␤-tubulin genes. The isolate, named Fusarium sp. strain BI, grew to equivalent densities when using salicylate or bismuth subsalicylate as carbon sources. Bismuth nitrate at concentrations of up to 200 M did not limit growth of this organism on glucose. The concentration of soluble bismuth in suspensions of bismuth subsalicylate decreased during growth of Fusarium sp. strain BI. Transmission electron microscopy and energy-dispersive spectroscopy revealed that the accumulated bismuth was localized in phosphorus-rich granules distributed in the cytoplasm and vacuoles. Long-chain polyphosphates were extracted from fresh biomass grown on bismuth subsalicylate, and inductively coupled plasma optical emission spectrometry showed that these fractions also contained high concentrations of bismuth. Enzyme activity assays of crude extracts of Fusarium sp. strain BI showed that salicylate hydroxylase and catechol 1,2-dioxygenase were induced during growth on salicylate, indicating that this organism degrades salicylate by conversion of salicylate to catechol, followed by ortho cleavage of the aromatic ring. Catechol 2,3-dioxygenase activity was not detected. Fusarium sp. strain BI grew with several other aromatic acids as carbon sources: benzoate, 3-hydroxybenzoate, 4-hydroxybenzoate, gentisate, D-mandelate, L-phenylalanine, L-tyrosine, phenylacetate, 3-hydroxyphenylacetate, 4-hydroxyphenylacetate, and phenylpropionate.

SOLiD-SAGE of Endophyte-Infected Red Fescue Reveals Numerous Effects on Host Transcriptome and an Abundance of Highly Expressed Fungal Secreted Proteins

“…A Fusarium sp. was identified that could use salicylate as its sole carbon source and salicylate hydroxylase activity was detected [51], so it is possible that the endophyte salicylate hydroxylase gene is correctly annotated.…”

Cytotoxicity of Bismuth Compounds to Cultured Cancer Cells

“…Gallic acid displayed substantial toxicity, followed by the toxicity of Bi subgallate combined with gallic acid ( Figure 2). This finding indicates that Bi can mitigate the cytotoxicity of gallic acid; perhaps ionic Bi forms a complex with free gallic acid, regulating its permeation of the cell membrane [8,9]. It seems that not contrary to the fact that the ratio of free Bi ions in the culture solution is low in the case of organic acid salts such as subgallate.…”

“…It seems that not contrary to the fact that the ratio of free Bi ions in the culture solution is low in the case of organic acid salts such as subgallate. Bi can be detoxified by chelation [10,11], although some amino acids and soil fungi have been shown to enhance its toxicity [8,9]. In this study, we conducted only a very basic examination of cytotoxicity in a human thyroid cancer cell line.…”

Metabolism of Thioamides by Ralstonia pickettii TA

“…Enrichment cultures were conducted in a nitrogen-free minimal medium composed of a 0.050 M potassium phosphate buffer (pH 7) supplemented with essential elements as described previously (14). Sodium acetate, D-glucose, and sodium succinate were included at 0.2% (wt/vol) each as carbon sources.…”

“…Template DNA for 16S rRNA gene PCR amplification was isolated from a single colony of the isolate from a thioacetamide-minimal medium plate by using a boiling preparation method described previously (14). Primers 27F and 1525R were used for amplification (27).…”