Identification of volatiles from six marine Celeribacter strains

Abstract

The volatiles emitted from six marine Rhodobacteraceae species of the genus Celeribacter were investigated by GC–MS. Besides several known compounds including dimethyl trisulfide and S-methyl methanethiosulfonate, the sulfur-containing compounds ethyl (E)-3-(methylsulfanyl)acrylate and 2-(methyldisulfanyl)benzothiazole were identified and their structures were verified by synthesis. Feeding experiments with [methyl-2H3]methionine, [methyl-13C]methionine and [34S]-3-(dimethylsulfonio)propanoate (DMSP) resulted in the high incorporation into dimethyl trisulfide and S-methyl methanethiosulfonate, and revealed the origin of the methylsulfanyl group of 2-(methyldisulfanyl)benzothiazole from methionine or DMSP, while the biosynthetic origin of the benzothiazol-2-ylsulfanyl portion could not be traced. The heterocyclic moiety of this compound is likely of anthropogenic origin, because 2-mercaptobenzothiazole is used in the sulfur vulcanization of rubber. Also in none of the feeding experiments incorporation into ethyl (E)-3-(methylsulfanyl)acrylate could be observed, questioning its bacterial origin. Our results demonstrate that the Celeribacter strains are capable of methionine and DMSP degradation to widespread sulfur volatiles, but the analysis of trace compounds in natural samples must be taken with care.

Atmospheric Benzothiazoles in a Coastal Marine Environment

“…While benzothiazoles are high-volume industrial chemicals and are commonly studied as wastewater contaminants in coastal areas, there are also marine biogenic sources of benzothiazoles. , Coupled with the early bloom increase in gas and aerosol-phase benzothiazole levels that cannot be explained by (do not correlate with) either the rising temperatures or indicators of biological activity (including chlorophyll-a concentrations, heterotrophic bacteria concentrations, and peaks in typical biogenic gases such as DMS and isoprene) (Figure ), this necessitates a more nuanced investigation of the most probable origins of the benzothiazoles observed at the SeaSCAPE campaign and in ambient air at Scripps Pier. Prominent among benzothiazoles in both dissolved and aerosol phases and observed in particularly high abundance in the dissolved phase was 2-(methylthio)­benzothiazole, a known and commonly reported tracer of anthropogenic benzothiazoles originating from runoff or wastewater. ,, Compared to other anthropogenic benzothiazole tracers, 2-(methylthio)­benzothiazole is relatively resistant to both photochemical and biological degradation, and is itself a biodegradation product of another commonly reported anthropogenic benzothiazole, 2-mercaptobenzothiazole .…”

“…31,32,15,33,13,34 Benzothiazoles are a class of anthropogenic pollutants that have been previously reported and in a variety of freshwater and coastal aquatic environments, including the southern California coast, 35−40 but they are also produced biogenically from select marine microbiological species. 41,42 Benzothiazole (hereafter BT) (C 7 H 5 NS) is an aromatic heterocyclic organic compound containing both sulfur and nitrogen. Benzothiazoles are here defined as compounds containing a benzothiazole moiety.…”

The Stereochemical Course of DmdC, an Enzyme Involved in the Degradation of Dimethylsulfoniopropionate

“…Another fraction of DMSP is oxidised to dimethylsulfoxonium propionate (DMSOP), [32] but no enzyme is known for this important transformation. The cleavage of DMSOP leads to the non‐volatile and water soluble metabolite dimethylsulfoxide (DMSO), a reaction that can be catalysed by DMSP lyases in vitro and in vivo [32–34] . These reactions limit the sulfur flux from the oceans, as does the breakdown through the demethylation pathway that proceeds with the action of four enzymes [35,36] and is the major pathway for DMSP degradation [37] .…”

On the Substrate Scope of Dimethylsulfonium Propionate Lyases toward Dimethylsulfoxonium Propionate Derivatives

“…More recently, the oxidized DMSP derivative dimethylsulfoxonium propionate (DMSOP) has been discovered that is also highly abundant in the marine environment (Scheme 1C) [39] . While no enzymes for the oxidation of DMSP to DMSOP have been described so far, recent research has demonstrated that the known DMSP lyases can cleave DMSOP with formation of dimethylsulfoxide (DMSO) and acrylate [40,41] …”