Biological Functions of Diallyl Disulfide, a Garlic-Derived Natural Organic Sulfur Compound

Garlic is widely accepted as a functional food and an excellent source of pharmacologically active ingredients. Diallyl disulfide (DADS), a major bioactive component of garlic, has several beneficial biological functions, including anti-inflammatory, antioxidant, antimicrobial, cardiovascular protective, neuroprotective, and anticancer activities. This review systematically evaluated the biological functions of DADS and discussed the underlying molecular mechanisms of these functions. We hope that this review provides guidance and insight into the current literature and enables future research and the development of DADS for intervention and treatment of multiple diseases.

Uptake of Dimethylsulfoniopropionate (DMSP) by Natural Microbial Communities of the Great Barrier Reef (GBR), Australia

Dimethylsulfoniopropionate (DMSP) is a key organic sulfur compound that is produced by many phytoplankton and macrophytes and is ubiquitous in marine environments. Following its release into the water column, DMSP is primarily metabolised by heterotrophic bacterioplankton, but recent evidence indicates that non-DMSP producing phytoplankton can also assimilate DMSP from the surrounding environment. In this study, we examined the uptake of DMSP by communities of bacteria and phytoplankton within the waters of the Great Barrier Reef (GBR), Australia. We incubated natural GBR seawater with DMSP and quantified the uptake of DMSP by different fractions of the microbial community (>8 µm, 3–8 µm, <3 µm). We also evaluated how microbial community composition and the abundances of DMSP degrading genes are influenced by elevated dissolved DMSP levels. Our results showed uptake and accumulation of DMSP in all size fractions of the microbial community, with the largest fraction (>8 µm) forming the dominant sink, increasing in particulate DMSP by 44–115% upon DMSP enrichment. Longer-term incubations showed however, that DMSP retention was short lived (<24 h) and microbial responses to DMSP enrichment differed depending on the community carbon and sulfur demand. The response of the microbial communities from inside the reef indicated a preference towards cleaving DMSP into the climatically active aerosol dimethyl sulfide (DMS), whereas communities from the outer reef were sulfur and carbon limited, resulting in more DMSP being utilised by the cells. Our results show that DMSP uptake is shared across members of the microbial community, highlighting larger phytoplankton taxa as potentially relevant DMSP reservoirs and provide new information on sulfur cycling as a function of community metabolism in deeper, oligotrophic GBR waters.

Allicin, the Odor of Freshly Crushed Garlic: A Review of Recent Progress in Understanding Allicin’s Effects on Cells

The volatile organic sulfur compound allicin (diallyl thiosulfinate) is produced as a defense substance when garlic (Allium sativum) tissues are damaged, for example by the activities of pathogens or pests. Allicin gives crushed garlic its characteristic odor, is membrane permeable and readily taken up by exposed cells. It is a reactive thiol-trapping sulfur compound that S-thioallylates accessible cysteine residues in proteins and low molecular weight thiols including the cellular redox buffer glutathione (GSH) in eukaryotes and Gram-negative bacteria, as well as bacillithiol (BSH) in Gram-positive firmicutes. Allicin shows dose-dependent antimicrobial activity. At higher doses in eukaryotes allicin can induce apoptosis or necrosis, whereas lower, biocompatible amounts can modulate the activity of redox-sensitive proteins and affect cellular signaling. This review summarizes our current knowledge of how bacterial and eukaryotic cells are specifically affected by, and respond to, allicin.

Influence of Oxidation of Copper on Shear Bond Strength to an Acrylic Resin Using an Organic Sulfur Compound

The aim of this study was to clarify the influence of the copper surfaces changed from Cu or Cu2O to CuO on the bonding strength of resin with organic sulfur compounds. The disk-shaped specimens (n = 44) of copper were wet-ground. Half of the specimens were heated at 400 °C for 4 min in an electric furnace (HT: heated). Half of the specimens were not heated (UH: unheated). The specimens were further divided into two groups. Each group was primed by 6-methacryloyloxyhexyl 2-thiouracil-5-carboxylate (MTU-6) or unprimed (n = 11). A statistical analysis of the results of shear bond strength testing was performed, and the failure mode of the bonded areas was classified with an optical microscope. Two types of specimen surface (UH or HT) were analyzed chemically using X-ray photoelectron spectroscopy (XPS). When primed with MTU-6, unheated Cu (28.3 MPa) showed greater bond strength than heated (19.1 MPa). When unprimed, heated Cu (4.1 MPa) showed greater bond strength than unheated (2.3 MPa). The results of the debonded surfaces observation showed that only the UH-MTU-6 group demonstrated a combination of adhesive and cohesive failures in all specimens. The XPS results showed that the surface of copper changed from Cu or Cu2O to CuO when HT. These results confirmed that it is necessary to take care of the copper oxide contained in noble metal alloys when using organic sulfur compounds for adhesion.

Variability of sulphur compounds at the Boknis Eck Time-Series Station in the Baltic Sea during 2009-2016

&lt;p&gt;Dimethyl sulphide (DMS), as a volatile organic sulfur compound, plays an important role among the reduced sulphur gases in the atmosphere. DMS emitted from seawater constitutes a significant component of the global sulphur cycle and may affect climate by forming atmospheric aerosols which could form cloud condensation nuclei and thus modify cloud properties. DMS is produced from its major precursor dimethylsulphoniopropionate (DMSP) by complex interactions of phytoplankton and bacterial processes. Dimethyl sulphoxide (DMSO) is the major non-volatile dimethyl sulphur pool in the ocean and plays an important role in the biogeochemical cycle of DMS, although its formation and consumption pathways are poorly understood compared to DMSP.&lt;/p&gt;&lt;p&gt;Although the Baltic Sea is the largest brackish water system of the world, observations of sulphur compounds from the Baltic Sea are limited. The variations of seawater DMS, DMSP and DMSO as well as various phytoplankton marker pigments were investigated at the Boknis Eck Time-Series Station (BE, located in Eckernf&amp;#246;rde Bay, southwest Baltic Sea) during the period 2009 - 2016. &amp;#160;Average DMS (1.8 nmol L&lt;sup&gt;&amp;#8722;1&lt;/sup&gt;), dissolved DMSP (DMSP&lt;sub&gt;d&lt;/sub&gt;, 3.3 nmol L&lt;sup&gt;&amp;#8722;1&lt;/sup&gt;) and particulate DMSP (DMSP&lt;sub&gt;p&lt;/sub&gt;, 10.5 nmol L&lt;sup&gt;&amp;#8722;1&lt;/sup&gt;) concentrations were generally low, while dissolved DMSO (DMSO&lt;sub&gt;d&lt;/sub&gt;, 14.6 nmol L&lt;sup&gt;&amp;#8722;1&lt;/sup&gt;) and particulate DMSO (DMSO&lt;sub&gt;p&lt;/sub&gt;, 13.1 nmol L&lt;sup&gt;&amp;#8722;1&lt;/sup&gt;) concentrations were comparably enhanced in the water column during the study. Strong seasonal variations in the concentrations of the sulphur compounds have been linked to the phytoplankton succession over the entire investigation period. Depth profiles of sulphur compounds were generally related to Chlorophyll a concentrations. The averaged DMS flux was 16.3 &amp;#181;mol m&lt;sup&gt;-2&lt;/sup&gt; day&lt;sup&gt;-1 &lt;/sup&gt;suggesting that BE is a net source of atmospheric DMS. Monthly averaged air-to-sea DMS fluxes at BE varied considerably and they were well-correlated with surface DMS concentrations as well as the relative abundance of haptophytes instead of the wind speed. This time-series study illustrates the importance of phytoplankton community in shaping the distribution of the sulphur compounds and fluxes to the atmosphere in the Baltic Sea.&lt;/p&gt;

The effect of sulfur compounds on the content of microelements in tissue organism rabbits

The aim of the study was to investigate the effect of nanotechnology and sodium sulfate on the content of mineral elements in the tissues of 110-day-old rabbits by feeding different amounts of nano sulfur citrate. Studies were conducted on young rabbits of the Hyla breed in the private sector. Rabbits for the study were selected at the age of 41 days on the principle of analogues, weighing 1.2–1.4 kg, were divided into six groups (control and five experimental), 6 animals (3 males and 3 females) in each. Animals were kept in rooms with adjustable microclimate and illumination in mesh cages measuring 50×120×30 cm, in accordance with modern animal health standards. The rabbits of the control group were fed without restriction a balanced granular compound feed, with free access to water. Animals of the first (I), second (II), third (III), and fourth (IV) experimental groups were fed a control group diet and fed with nano sulfur citrate for 2; 4; 8 and 12 mg S/kg body weight. A solution of nano sulfur citrate (1.0 g/dm3, pH 1.38) was obtained from the Nanomaterials and Nanotechnologies LLC, Kyiv. The young of the fifth (V) experimental group was fed with a diet of the control group and water was given sodium sulfate (Na2SO4) in the amount of 40 mg S/kg body weight. At the 58th day from the beginning of the experiment, the animals were slaughtered, taking into account the generally accepted bioethical norms of international regulations regarding the experimental work with vertebrate animals. Blood, tissues: liver, skin and wool were selected for the study. For determination of macro and microelements, the samples were pre-mineralized by dry aching method. After ashes, acid extraction was performed. In the prepared samples, the elements were determined by atomic absorption spectrophotometry using AAS-115 C. The digital data were statistically processed using the Student's t test. Studies have found that the feeding of rabbit sulfur citrate in the smallest amount tested 2 mg/kg caused a significant increase in liver – Fe (P < 0.05) and skin – Zn (P < 0.05), whereas a larger dose of 4 mg/kg was affected by changes in blood Cr and Fe (P < 0.01), liver – Zn and Fe (P < 0.05), skin – Zn (P < 0.01), wool – Zn and Fe (P < 0.05) compared to the control group. It was noted that the use in the diet of rabbits supplements of sulfur citrate at the rate of 8 mg/kg was marked by the greatest changes in the investigated tissues of the rabbit body, in particular the higher blood levels of Cr (P<0,001), Fe (P<0,05) and Cu (P < 0.01), liver – Zn, Fe and Cu (P < 0.05), skin – Zn (P < 0.001), higher amounts of 12 mg/kg caused changes in liver content – Zn (P < 0.01) and Fe (P < 0.05), skin – Zn (P < 0.05) compared to the control, indicating the stimulating effect of the organic sulfur compound on the activation of the processes of assimilation of these elements in their body. The use of sodium sulfate in the amount of 40 mg S/kg body weight was less likely to affect the content of the studied mineral elements compared with the control group with a more pronounced effect: Zn in the liver and skin, Cr in wool. Therefore, feeding in the diet of rabbits II and III experimental groups of nano sulfur citrate in the amount of 4 and 8 S/kg body weight was more pronounced synergistic effect on the trace elements in the tissues of their body than the use of inorganic compounds and the control group.

Impact of sea-ice melt on dimethyl sulfide (sulfoniopropionate) inventories in surface waters of Marguerite Bay, West Antarctic Peninsula

The Southern Ocean is a hotspot of the climate-relevant organic sulfur compound dimethyl sulfide (DMS). Spatial and temporal variability in DMS concentration is higher than in any other oceanic region, especially in the marginal ice zone. During a one-week expedition across the continental shelf of the West Antarctic Peninsula (WAP), from the shelf break into Marguerite Bay, in January 2015, spatial heterogeneity of DMS and its precursor dimethyl sulfoniopropionate (DMSP) was studied and linked with environmental conditions, including sea-ice melt events. Concentrations of sulfur compounds, particulate organic carbon (POC) and chlorophyll a in the surface waters varied by a factor of 5–6 over the entire transect. DMS and DMSP concentrations were an order of magnitude higher than currently inferred in climatologies for the WAP region. Particulate DMSP concentrations were correlated most strongly with POC and the abundance of haptophyte algae within the phytoplankton community, which, in turn, was linked with sea-ice melt. The strong sea-ice signal in the distribution of DMS(P) implies that DMS(P) production is likely to decrease with ongoing reductions in sea-ice cover along the WAP. This has implications for feedback processes on the region's climate system. This article is part of the theme issue ‘The marine system of the West Antarctic Peninsula: status and strategy for progress in a region of rapid change’.

Biodesulfurization of Dibenzothiophene by a Newly Isolated Agrobacterium tumefaciens LSU20

Organic sulfur compound of fossil fuel are too resistant to be removed by the conventional desulfurization processes. This study aimed to investigate the best growth conditions of Agrobacterium tumefaciens strain LSU20 on desulfurized of dibenzothiophene (DBT) compound in the n-tetradecane as model of oil. The experiments were performed with the medium two-phase system, aqueous phase: mineral salt sulfur free (MSSF) medium and the oil phase: n-tetradecane containing 200 ppm of DBT in the ratio of oil/water (1: 5). The culture of LSU20 that has been aged 4 days (OD660 5) of 0.1 ml inoculated in a test tube containing 5 mL of MSSF medium and 1 ml model of petroleum, grown at temperature variations incubation as follows: 33°C, 37°C, 41°C, 45°C, and 49°C; variations in the initial pH of medium: pH 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, and 8.0; and variations of carbon sources such as glucose, sucrose, glycerol and citric acid. The experiments were conducted using a water bath shaker at 150 rpm for 96 hours of incubation. The results showed that the highest rate of degradation of DBT by LSU20 occurs at a temperature of 37°C, media pH of 7 and glucose as the carbon source, ie with the growth rate reached 0.91 (OD660) and DBT compounds degraded until 76.9% (w/v).