Methylmercury (sometimes methyl mercury) is an organometallic cation with the formula [CH3Hg]+. Methylmercury is extremely toxic, and its derivatives are the major source of organic mercury for humans. It is a bioaccumulative environmental toxicant. Structure and chemistry
"Methylmercury" is a shorthand for the hypothetical "methylmercury cation", sometimes written "methylmercury(1+) cation" or "methylmercury(II) cation". This functional group is composed of a methyl group bonded to an atom of  mercury. Its chemical formula is CH3Hg+ (sometimes written as MeHg+). Methylmercury exists as a substituent in many complexes of the type [MeHgL]+ (L = Lewis base) and MeHgX (X = anion).As a positively charged ion it readily combines with anions such as chloride (Cl−), hydroxide (OH−) and nitrate (NO−3). It has particular affinity for sulfur-containing anions, particularly thiols (RS−). Thiols are generated when the amino acid cysteine and the peptide glutathione form strong complexes with methylmercury:
[MeHg]+ + RSH  →   MeHg−SR + H+

Sources
Environmental sources
Methylmercury is formed from inorganic mercury by the action of microbes that live in aquatic systems including lakes, rivers, wetlands, sediments, soils and the open ocean. This methylmercury production has been primarily attributed to anaerobic bacteria in the sediment. Significant concentrations of methylmercury in ocean water columns are strongly associated with nutrients and organic matter remineralization, which indicate that remineralization may contribute to methylmercury production. Direct measurements of methylmercury production using stable mercury isotopes have also been observed in marine waters, but the microbes involved are still unknown.
Results of a large-scale trial published in August 2021 suggest that inhaled budesonide improves the time of recovery and peoples well-being during the recovery process. The recommendation was withdrawn in December 2021 citing the need for more research.Inhalational budesonide was added to the recommended treatment for cases of COVID-19 in India in April 2021. References
External links
"Budesonide". Drug Information Portal. U.S. National Library of Medicine. "Budesonide Nasal Spray". MedlinePlus. "Budesonide Oral Inhalation". MedlinePlus.