Sulfhydryl Binding Sites within Bacterial Extracellular Polymeric Substances

Abstract

In this study, the concentration of sulfhydryl sites on bacterial biomass samples with and without extracellular polymeric substances (EPS) was measured in order to determine the distribution of sulfhydryl sites on bacteria. Three different approaches were employed for EPS removal from Pseudomonas putida, and the measured sulfhydryl concentrations on bacterial EPS molecules are independent of the EPS removal protocols used. Prior to EPS removal, the measured sulfhydryl sites within P. putida samples was 34.9 ± 9.5 μmol/g, and no sulfhydryl sites were detected after EPS removal, indicating that virtually all of the sulfhydryl sites are located on the EPS molecules produced by P. putida. In contrast, the sulfhydryl sites within the S. oneidensis samples increased from 32.6 ± 3.6 μmol/g to 51.9 ± 7.2 μmol/g after EPS removal, indicating that the EPS produced by S. oneidensis contained fewer sulfhydryl sites than those present on the untreated cells. This study suggests that the sulfhydryl concentrations on EPS molecules may vary significantly from one bacterial species to another, thus it is crucial to quantify the concentration of sulfhydryl sites on EPS molecules of other bacterial species in order to determine the effect of bacterial EPS on metal cycling in the environment.

Role of bacterial cell surface sulfhydryl sites in cadmium detoxification by Pseudomonas putida

“…The treated cells were then washed using the same procedure as described above. The biomass that is produced from this resin treatment procedure is virtually free of EPS materials, as previous studies have demonstrated with electron microscopy (Yu and Fein, 2016).…”

Interaction of Freshwater Diatom with Gold Nanoparticles: Adsorption, Assimilation, and Stabilization by Cell Exometabolites

“…15 µg/L at pH from 3 to 12, but decreased three-fold and then remained relatively constant or increased in the NaCl electrolyte. Net adsorption of AuNPs at the diatom surface is due to competition with H + for negativelycharged anionic surface sites (phosphorylates, sulphides), as it is fairly well established for divalent metals interacting with diatoms [31,34] and various bacteria [45]. The desorption with the increase of pH may be due to competition between aqueous ligands complexing AuNPs + particles and surface site moieties.…”

“…This and the previously described result may have important consequences for understanding the AuNPs interaction with photosynthesizing diatoms cells. It is possible that during the active phase of photosynthesis, during the day, when the pH in the pristine water layer surrounding the cells rises above 9, the diatoms will release AuNPs that were Net adsorption of AuNPs at the diatom surface is due to competition with H + for negatively-charged anionic surface sites (phosphorylates, sulphides), as it is fairly well established for divalent metals interacting with diatoms [31,34] and various bacteria [45]. The desorption with the increase of pH may be due to competition between aqueous ligands complexing AuNPs + particles and surface site moieties.…”

Influence of sulfhydryl sites on palladium (II) adsorption by displaying EC20 on the surface of Escherichia coli

“…The EC20 cells were suspended in a freshly prepared qBBr (Sigma, USA) solution as Fein et al . described except that the qBBr:biomass ratio was approximately 40 μmol g −1 . The BL21, EC20 and qBBr‐EC20 wet biomasses were used immediately for Pd (II) adsorption.…”

“…During the interaction between qBBr and sulfhydryl sites, the bromine atom of qBBr is replaced by the sulfur atom from a sulfhydryl site. Therefore, qBBr can form strong covalent bonds with the exposed sulfhydryl sites and results in blocking of the sulfhydryl site …”