scholarly journals Modified cyclodextrins solubilize elemental sulfur in water and enable biological sulfane sulfur delivery

2020 ◽  
Vol 11 (43) ◽  
pp. 11777-11784
Author(s):  
Sarah G. Bolton ◽  
Michael D. Pluth
Keyword(s):  
Elemental Sulfur ◽  
Live Cells ◽  
Sulfane Sulfur ◽  
Modified Cyclodextrins

Sulfane sulfur, or S0, is found in polysulfide and persulfide compounds in biology. We demonstrate that modified cyclodextrins can solubilize S8 in water, increase its reactivity with biological nucleophiles, and enable delivery to live cells.

scholarly journals Modified Cyclodextrins Solubilize Elemental Sulfur in Water and Enable Biological Sulfane Sulfur Delivery

2020 ◽  
Author(s):  
Sarah Bolton ◽  
Michael Pluth
Keyword(s):  
Elemental Sulfur ◽  
Complex Environments ◽  
Solubility In Water ◽  
Sulfane Sulfur ◽  
New Strategy ◽  
Raw 264.7 Macrophage Cells ◽  
And Storage ◽  
Low Solubility ◽  
Important Form ◽  
Mediated Reduction

An important form of biological sulfur is sulfane sulfur, or S<sup>0</sup>, which is found in polysulfide and persulfide compounds as well as in elemental sulfur. Sulfane sulfur, often in the form of S<sub>8</sub>, functions as a key energy source in the metabolic processes of thermophilic Archaean organisms found in sulfur-rich environments and can be metabolized both aerobically and anaerobically by different archaeons. Despite this importance, S<sub>8</sub> has a low solubility in water (~19 nM), raising questions of how it can be solubilized and made chemically accessible in complex environments. Motivated by prior crystallographic data showing S<sub>8</sub> binding to hydrophobic motifs in filamentous glycoproteins from the sulfur reducing <i>Staphylothermus marinus</i> anaerobe, we demonstrate that simple hydrophobic motifs, such as 2-hydroxypropyl β-cyclodextrin (2HPβ), are sufficient solubilize S<sub>8</sub> at concentrations up to 2.0 ± 0.2 mM in aqueous solution. We demonstrate that the solubilized S<sub>8</sub> is chemically accessible, can be reduced with <i>tris</i>(2-carboxyethyl)phosphine (TCEP), and reacts with thiols to generate H<sub>2</sub>S. The thiol-mediated conversion of 2HPβ/S<sub>8</sub> to H<sub>2</sub>S ranges from 80% to quantitative efficiency for Cys and glutathione (GSH). Moreover, we demonstrate that 2HPβ can catalyze the reaction of Cys-mediated reduction of S<sub>8</sub> to H<sub>2</sub>S in water. Adding to the biological relevance of the developed systems, we demonstrate that treatment of Raw 264.7 macrophage cells with the 2HPβ/S<sub>8</sub> complex prior to LPS stimulation reduces NO<sub>2</sub><sup>–</sup> levels, which is consistent with known activities of bioavailable H<sub>2</sub>S and sulfane sulfur. Taken together, these investigations provide a new strategy for delivering H<sub>2</sub>S and sulfane sulfur in complex systems and more importantly provide new insights into the chemical accessibility and storage of S<sup>0</sup> and S<sub>8</sub> in biological environments.

scholarly journals Modified Cyclodextrins Solubilize Elemental Sulfur in Water and Enable Biological Sulfane Sulfur Delivery

2020 ◽  
Author(s):  
Sarah Bolton ◽  
Michael Pluth
Keyword(s):  
Elemental Sulfur ◽  
Complex Environments ◽  
Solubility In Water ◽  
Sulfane Sulfur ◽  
New Strategy ◽  
Raw 264.7 Macrophage Cells ◽  
And Storage ◽  
Low Solubility ◽  
Important Form ◽  
Mediated Reduction

An important form of biological sulfur is sulfane sulfur, or S<sup>0</sup>, which is found in polysulfide and persulfide compounds as well as in elemental sulfur. Sulfane sulfur, often in the form of S<sub>8</sub>, functions as a key energy source in the metabolic processes of thermophilic Archaean organisms found in sulfur-rich environments and can be metabolized both aerobically and anaerobically by different archaeons. Despite this importance, S<sub>8</sub> has a low solubility in water (~19 nM), raising questions of how it can be solubilized and made chemically accessible in complex environments. Motivated by prior crystallographic data showing S<sub>8</sub> binding to hydrophobic motifs in filamentous glycoproteins from the sulfur reducing <i>Staphylothermus marinus</i> anaerobe, we demonstrate that simple hydrophobic motifs, such as 2-hydroxypropyl β-cyclodextrin (2HPβ), are sufficient solubilize S<sub>8</sub> at concentrations up to 2.0 ± 0.2 mM in aqueous solution. We demonstrate that the solubilized S<sub>8</sub> is chemically accessible, can be reduced with <i>tris</i>(2-carboxyethyl)phosphine (TCEP), and reacts with thiols to generate H<sub>2</sub>S. The thiol-mediated conversion of 2HPβ/S<sub>8</sub> to H<sub>2</sub>S ranges from 80% to quantitative efficiency for Cys and glutathione (GSH). Moreover, we demonstrate that 2HPβ can catalyze the reaction of Cys-mediated reduction of S<sub>8</sub> to H<sub>2</sub>S in water. Adding to the biological relevance of the developed systems, we demonstrate that treatment of Raw 264.7 macrophage cells with the 2HPβ/S<sub>8</sub> complex prior to LPS stimulation reduces NO<sub>2</sub><sup>–</sup> levels, which is consistent with known activities of bioavailable H<sub>2</sub>S and sulfane sulfur. Taken together, these investigations provide a new strategy for delivering H<sub>2</sub>S and sulfane sulfur in complex systems and more importantly provide new insights into the chemical accessibility and storage of S<sup>0</sup> and S<sub>8</sub> in biological environments.

scholarly journals Sulfane sulfur – new findings on an old topic

2019 ◽  
Author(s):  
Malgorzata Iciek ◽  
Anna Bilska-Wilkosz ◽  
Magdalena Górny
Keyword(s):  
Elemental Sulfur ◽  
Antioxidant Properties ◽  
Sulfur Compounds ◽  
Reliable Determination ◽  
Sulfane Sulfur ◽  
Physiological Conditions ◽  
New Findings ◽  
Potential Applications ◽  
Divalent Sulfur

Sulfane sulfur is a divalent sulfur atom bonded to another sulfur which is very reactive and labile. Compounds containing this reactive sulfur include persulfides, polysulfides, thiosulfate, thiosulfinates, polythionates, and elemental sulfur. Sulfane sulfur appears in a number of biologically important compounds, including thiocysteine, thiocystine and thiotaurine, products of the cysteine metabolism, as well as glutathione persulfide. Sulfane sulfur compounds can modify cysteine residues in proteins via an S-sulfhydration reaction to produce protein persulfides. It has been also postulated that cysteine persulfides can be incorporated into proteins during translation. Recently, the sulfane sulfur compounds, especially the persulfides and polysulfides, have attracted increasing interest due to their regulatory and antioxidant properties. Compounds containing sulfane sulfur are also regarded as a form of H2S storage, which can easily release this gasotransmitter in response to biological signals. Both reactive sulfur species (H2S and sulfane sulfur) always coexist in biological systems. This review is focused on new findings in the field of sulfane sulfur’s biological role, and disruption of its level in some patho/physiological conditions. A few sulfane sulfur donors with potential applications are presented. In recent years, in parallel to increasing interest in biological importance of sulfane sulfur, new analytical methods have been developed for sensitive and reliable determination of its level in the cells and tissues.

The sulfane sulfur of persulfides is the actual substrate of the sulfur-oxidizing enzymes from Acidithiobacillus and Acidiphilium spp.

Microbiology ◽  
2003 ◽  
Vol 149 (7) ◽  
pp. 1699-1710 ◽  
Author(s):  
Thore Rohwerder ◽  
Wolfgang Sand
Keyword(s):  
Elemental Sulfur ◽  
Sulfide Oxidation ◽  
Sulfur Oxidation ◽  
Acidithiobacillus Thiooxidans ◽  
Sulfane Sulfur ◽  
Catalytic Role ◽  
Sulfur Oxidizing ◽  
Sulfur Containing ◽  
Actual Substrate ◽  
Sulfur Donor

To identify the actual substrate of the glutathione-dependent sulfur dioxygenase (EC 1.13.11.18) elemental sulfur oxidation of the meso-acidophilic Acidithiobacillus thiooxidans strains DSM 504 and K6, Acidithiobacillus ferrooxidans strain R1 and Acidiphilium acidophilum DSM 700 was analysed. Extraordinarily high specific sulfur dioxygenase activities up to 460 nmol min−1 (mg protein)−1 were found in crude extracts. All cell-free systems oxidized elemental sulfur only via glutathione persulfide (GSSH), a non-enzymic reaction product from glutathione (GSH) and elemental sulfur. Thus, GSH plays a catalytic role in elemental sulfur activation, but is not consumed during enzymic sulfane sulfur oxidation. Sulfite is the first product of sulfur dioxygenase activity; it further reacted non-enzymically to sulfate, thiosulfate or glutathione S-sulfonate (). Free sulfide was not oxidized by the sulfur dioxygenase. Persulfide as sulfur donor could not be replaced by other sulfane-sulfur-containing compounds (thiosulfate, polythionates, bisorganyl-polysulfanes or monoarylthiosulfonates). The oxidation of H2S by the dioxygenase required GSSG, i.e. the disulfide of GSH, which reacted non-enzymically with sulfide to give GSSH prior to enzymic oxidation. On the basis of these results and previous findings a biochemical model for elemental sulfur and sulfide oxidation in Acidithiobacillus and Acidiphilium spp. is proposed.

Scanning Electron Microscope Study of Bacteria on Mineral Surfaces

1976 ◽  
Vol 34 ◽  
pp. 130-131
Author(s):  
V.K. Berry
Keyword(s):  
Oxidation Reaction ◽  
Electron Microscope Study ◽  
Elemental Sulfur ◽  
Thiobacillus Ferrooxidans ◽  
Physical Contact ◽  
Metal Sulfides ◽  
Low Grade ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
Scanning Electron Microscope Study

There are two strains of bacteria viz. Thiobacillus thiooxidansand Thiobacillus ferrooxidanswidely mentioned to play an important role in the leaching process of low-grade ores. Another strain used in this study is a thermophile and is designated Caldariella .These microorganisms are acidophilic chemosynthetic aerobic autotrophs and are capable of oxidizing many metal sulfides and elemental sulfur to sulfates and Fe2+ to Fe3+. The necessity of physical contact or attachment by bacteria to mineral surfaces during oxidation reaction has not been fairly established so far. Temple and Koehler reported that during oxidation of marcasite T. thiooxidanswere found concentrated on mineral surface. Schaeffer, et al. demonstrated that physical contact or attachment is essential for oxidation of sulfur.

4-dimensional, high-resolution imaging of living cells

1992 ◽  
Vol 50 (1) ◽  
pp. 416-417
Author(s):  
Shinya Inoué
Keyword(s):  
Light Microscope ◽  
Living Cells ◽  
Live Cells ◽  
Video Tape ◽  
Active Living ◽  
High Resolution Imaging ◽  
3 Dimensional ◽  
Dynamic Architecture ◽  
Resolution Imaging ◽  
Disk Memory

This paper reports progress of our effort to rapidly capture, and display in time-lapsed mode, the 3-dimensional dynamic architecture of active living cells and developing embryos at the highest resolution of the light microscope. Our approach entails: (A) real-time video tape recording of through-focal, ultrathin optical sections of live cells at the highest resolution of the light microscope; (B) repeat of A at time-lapsed intervals; (C) once each time-lapsed interval, an image at home focus is recorded onto Optical Disk Memory Recorder (OMDR); (D) periods of interest are selected using the OMDR and video tape records; (E) selected stacks of optical sections are converted into plane projections representing different view angles (±4 degrees for stereo view, additional angles when revolving stereos are desired); (F) analysis using A - D.

Multi-mode light microscopy of microtubule assembly dynamics and chromosome movement in vivo and In vitro

1996 ◽  
Vol 54 ◽  
pp. 730-731
Author(s):  
E. D. Salmon ◽  
J. C. Waters ◽  
C. Waterman-Storer
Keyword(s):  
Imaging System ◽  
Ccd Camera ◽  
Transmitted Light ◽  
Microtubule Assembly ◽  
Live Cells ◽  
Optical Efficiency ◽  
Multiple Band ◽  
Multi Mode

We have developed a multi-mode digital imaging system which acquires images with a cooled CCD camera (Figure 1). A multiple band pass dichromatic mirror and robotically controlled filter wheels provide wavelength selection for epi-fluorescence. Shutters select illumination either by epi-fluorescence or by transmitted light for phase contrast or DIC. Many of our experiments involve investigations of spindle assembly dynamics and chromosome movements in live cells or unfixed reconstituted preparations in vitro in which photodamage and phototoxicity are major concerns. As a consequence, a major factor in the design was optical efficiency: achieving the highest image quality with the least number of illumination photons. This principle applies to both epi-fluorescence and transmitted light imaging modes. In living cells and extracts, microtubules are visualized using X-rhodamine labeled tubulin. Photoactivation of C2CF-fluorescein labeled tubulin is used to locally mark microtubules in studies of microtubule dynamics and translocation. Chromosomes are labeled with DAPI or Hoechst DNA intercalating dyes.

Characterization of a Motile Cellular Domain Arising During the Amoebo-Flagellate Transformation of Physarum Polycephalum

1980 ◽  
Vol 38 ◽  
pp. 552-553
Author(s):  
K.I. Pagh ◽  
M.R. Adelman
Keyword(s):  
Cell Shape ◽  
Physarum Polycephalum ◽  
Slime Mold ◽  
Live Cells ◽  
Cellular Domain

Unicellular amoebae of the slime mold Physarum polycephalum undergo marked changes in cell shape and motility during their conversion into flagellate swimming cells (l). To understand the processes underlying motile activities expressed during the amoebo-flagellate transformation, we have undertaken detailed investigations of the organization, formation and functions of subcellular structures or domains of the cell which are hypothesized to play a role in movement. One focus of our studies is on a structure, termed the “ridge” which appears as a flattened extension of the periphery along the length of transforming cells (Fig. 1). Observations of live cells using Nomarski optics reveal two types of movement in this region:propagation of undulations along the length of the ridge and formation and retraction of filopodial projections from its edge. The differing activities appear to be associated with two characteristic morphologies, illustrated in Fig. 1.

Sign in / Sign up

Export Citation Format

Share Document