The role of fecal sulfur metabolome in inflammatory bowel diseases.

Sulfur metabolism and sulfur-containing metabolites play an important role in the human digestive system, and sulfur compounds and pathways are associated with inflammatory bowel diseases (IBD). In fact, cysteine metabolism results in the production of taurine and sulfate, and gut microbes catabolize them into hydrogen sulfide, a signaling molecule with various biological functions. Besides metabolites originating from sulfur metabolism, several other sulfur-containing metabolites of different classes were detected in human feces, consisting of non-volatile and volatile compounds. Sulfated steroids and bile acids such as taurine-conjugated bile acids are the major classes along with sulfur amino acids and sulfur-containing peptides. Indeed, sulfur-containing metabolites were described in stool samples from healthy subjects, patients suffering from colorectal cancer or IBD. In metabolomics-driven studies, around 50 known sulfur-containing metabolites were linked to IBD. Taurine, taurocholic acid, taurochenodeoxycholic acid, methionine, methanethiol and hydrogen sulfide were regularly reported in IBD studies, and most of them were elevated in stool samples from IBD patients. We summarized from this review that there is strong interplay between perturbed gut microbiota in IBD, and the consistently higher abundance of sulfur-containing metabolites, which potentially represent substrates for sulfidogenic bacteria such as Bilophila or Escherichia and promote their growth. These bacteria might shift their metabolism towards the degradation of taurine and cysteine and therefore to a higher hydrogen sulfide production.

Importance of sulfur-containing metabolites in discriminating fecal extracts between normal and type-2 diabetic mice.

A metabolic disorder such as Type-2 Diabetes mellitus (T2DM) is a complex disease induced by genetic, environmental, and nutritional factors. The db/db mouse model, bearing a nonfunctional leptin receptor, is widely used to investigate the pathophysiology of T2DM. Fecal extracts of db/db and wild-type littermates were studied to unravel a broad spectrum of new and relevant metabolites related to T2DM as proxies of the interplay of gut microbiome and murine metabolomes. The nontargeted metabolomics approach consists of an integrated analytical concept of high-resolution mass spectrometry FT-ICR-MS, followed by UPLC-TOF-MS/MS experiments. We demonstrate that a metabolic disorder such as T2DM affects the gastrointestinal tract environment, thereby influencing different metabolic pathways and their respective metabolites in diabetic mice. Fatty acids, bile acids concerning cholic and deoxycholic acid, and steroid metabolism were highly discriminative comparing fecal meta-metabolomes of wt and db/db mice. Furthermore, sulfur-(S)-containing metabolites including N-acyl taurines were altered in diabetic mice, enabling us to focus on S-containing metabolites, especially the sulfate and taurine conjugates of bile and fatty acids. Different sulfate containing bile acids including sulfocholic acid, oxocholic acid sulfate, taurocholic acid sulfate, and cyprinol sulfate were significantly altered in diabetic mice. Moreover, we identified 12 new sulfate and taurine conjugates of hydroxylated fatty acids with significant importance in T2DM metabolism in db/db mice.

Foliar Application of Sulfur-Containing Compounds-Pros and Cons.

Sulfate is taken up from the soil solution by the root system; and inside the plant, it is assimilated to hydrogen sulfide, which in turn is converted to cysteine. Sulfate is also taken up by the leaves, when foliage is sprayed with solutions containing sulfate fertilizers. Moreover, several other sulfur (S)-containing compounds are provided through foliar application, including the S metabolites hydrogen sulfide, glutathione, cysteine, methionine, S-methylmethionine, and lipoic acid. However, S compounds that are not metabolites, such as thiourea and lignosulfonates, along with dimethyl sulfoxide and S-containing adjuvants, are provided by foliar application-these are the S-containing agrochemicals. In this review, we elaborate on the fate of these compounds after spraying foliage and on the rationale and the efficiency of such foliar applications. The foliar application of S-compounds in various combinations is an emerging area of agricultural usefulness. In the agricultural practice, the S-containing compounds are not applied alone in spray solutions and the need for proper combinations is of prime importance.

Metabolic variation in the pulps of two durian cultivars: Unraveling the metabolites that contribute to the flavor.

Durian (Durio zibethinus M.) is a major economic fruit crop in Thailand. In this study, two popular cultivars, namely Chanee and Mon Thong, were collected from three orchards located in eastern Thailand. The pulp metabolome, including 157 annotated metabolites, was explored using capillary electrophoresis-time of flight/mass spectrometry (CE-TOF/MS). Cultivars and harvest years had more impact on metabolite profile separation than cultivation areas. We identified cultivar-dependent metabolite markers related to durian fruit quality traits, such as nutritional value (pyridoxamine), odor (cysteine, leucine), and ripening process (aminocyclopropane carboxylic acid). Interestingly, durian fruit were found to contain high amounts of γ-glutamylcysteine (810.3 ±â€¯257.5 mg/100 g dry weight) and glutathione (158.1 ±â€¯80.4 mg/100 g dry weight), which act as antioxidants and taste enhancers. This metabolite information could be related to consumer preferences and exploited for durian fruit quality improvement.