Selenium metabolism in a strain ofFusarium

Abstract

Fusarium sp. was isolated from Sinai soil at Egypt. It showed tendency to tolerate high concentrations of selenium in the form of sodium selenite up to 3.5% (w/v). The microscopic examination revealed some morphological distortions. However, the fungus was capable to circumvent the toxic effect of selenium. The fungus possess strong reducing ability as high quantities of elemental selenium were precipitated within the fungal cells as well as on the surface of the fungal hyphae and spores. The presence of selenium increased the cellular contents of carbohydrates, proteins, and lipids. Labeling studies indicate the incorporation of selenite into certain amino acids: selenocysteine and selenocysteic acid. Moreover, the presence of selenium induced the biosynthesis of several types of low molecular weight proteins. The results demonstrated different modes of detoxification of selenium toxicity.

Effects of selenium oxyanions on the white-rot fungus Phanerochaete chrysosporium

“…9a). This is consistent with previous research conducted with other fungal strains (Ramadan et al 1988). Similar effects have been observed for different fungal species exposed to heavy metals (Graz et al 2011;Kim et al 2003).…”

“…(Moss et al 1987;Gharieb et al 1995), Fusarium sp. (Ramadan et al 1988;Gharieb et al 1995), Mortierella spp. (Zieve et al 1985), Penicillium spp.…”

“…There has been some research on the metabolism of Se in filamentous fungi, including uptake and volatilization (Barkes and Fleming 1974;Fleming and Alexander 1972;Gharieb et al 1995;Tweedie and Segel 1970;Ramadan et al 1988); however, the information is still scarce. The limited knowledge regarding Se-fungi interactions hampers the full exploitation of fungi in Se remediation technologies and as nSe 0 producing agents.…”

Microbial solubilization and immobilization of toxic metals: key biogeochemical processes for treatment of contamination

“…In contrast to bacterial systems, fungal reduction of metalloids has received less biochemical attention although it is known that numerous filamentous and unicellular fungal species are capable of SeO 2− 3 reduction to Se o , resulting in a red coloration of colonies [67, 83–85]. Both extracellular and intracellular deposition of Se° has been demonstrated [67].…”

Characterization of rhizosphere fungi from selenium hyperaccumulator and nonhyperaccumulator plants along the eastern Rocky Mountain Front Range

“…There has been some research on the metabolism of Se in fi lamentous fungi, including uptake and volatilization ( Tweedie and Segel, 1970 ;Fleming and Alexander, 1972 ;Fleming, 1974 , 1976 ;Ramadan et al, 1989 ;Gharieb et al, 1995 ), but little on the infl uence of Se on fungi in relation to their environment, competition, or survival ( States, 1966 ;Ellil, 1999 ;Hefnawy, 2002 ). One interesting report found mycorrhizal fungi to enhance Se accumulation in garlic, resulting in a signifi cant (10-fold) increase in Se concentration in the plant tissue when compared to nonmycorrhizal controls ( Larsen et al, 2006 ).…”