bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulation of steroidogenesis by selenium in a novel adrenal cell line developed using targeted tumorigenesis
Authors: Chanoine Jean‐Pierre , Compagnone Nathalie A. , Wong Alfred C. K. , Mellon Synthia H.
Published: December 2008

Glutathione peroxidase (GPx‐1) is a selenoenzyme that metabolizes H2O2, a source of potentially toxic free radicals. Steroidogenesis is markedly inhibited by H2O2 in vitro.

Objective: to study the effects of selenium deficiency on GPx activity and adrenal steroidogenesis in a novel adrenal cell line developed using targeted tumorigenesis.

Methods: AN4Rppc7 cells were grown for 7 days in serum‐free medium. 8‐Br‐cAMP‐stimulated concentrations of steroid hormones were measured by RIA. StAR (Steroid Acute Reactive Protein) mRNA was measured by Northern blot.

Results: selenium deficiency caused a 99% There was a 51%, progesterone, corticosterone and aldosterone production, respectivelyp<0.05 by ANOVA). StAR mRNA was not affected by selenium.

Conclusions: selenium deficiency causes a marked decrease in GPx activity. Decreased steroid hormone production occurs for selenium concentrations equal or lower than 5 nM. The absence of changes in StAR mRNA content suggests that selenium deficiency does not affect cholesterol access to the mitochondria.
Bioremediation of selenium‐contaminated sediments and water
Authors: Frankenberger William T. , Arshad Muhammad
Published: December 2008

Selenium (Se) is a contaminant of agricultural irrigation‐drainage water in the western United States, and the cause of wildlife deaths and grotesque deformities. Some approaches in reducing the toxic Se concentrations from contaminated sediments and water have been proposed, but most of these tend to be costly or ineffective. Bioremediation through microbial transformations of toxic Se species into nontoxic forms is being considered as an effective remedial alternative. The microbial reduction of toxic oxyanions of Se {SeO42 and SeO32‐} into insoluble Se0 or methylation of these species to dimethylselenide (DMSe) has been accepted as a potential bioremediation strategy for cleanup of Se‐contaminated water and sediments. By conducting a series of laboratory, bench‐scale and field studies, we have thoroughly investigated the remedial potential of these approaches. It was observed that microorganisms, particularly Enterobacter cloacea, are very active in reduction of Se oxyanions present in irrigation drainage water, into insoluble Se0and, by monitoring various environmental conditions and addition of organic amendments, the process could be stimulated manifold. Similarly, the process of biomethylation of Se in soil sediments and water was found active and highly dependent on specific carbon amendments (pectin and proteins), pH, temperature, moisture, aeration and activators (cofactors). Moreover, Se biomethylation was protein/peptide‐limited rather than nitrogen‐, amino acid‐ or carbon‐limited. Crude casein and its components were equally stimulatory producing a > 50‐fold enhancement in DMSe yield. Methionine and methyl cobalamin stimulated DMSe production by Alternaria alternata, indicating that the coenzyme may mediate the transfer of a methyl group to the Se atom. An acute toxicity test involving inhalation of DMSe by rats revealed that DMSe is nontoxic. Experiments were scaled up from laboratory studies to field plots to verify the feasibility of this bioremediation approach. Based upon the promising results of these studies, a biotechnology prototype was developed which could be applicable for cleanup of polluted sediments and water throughout the western United States.