Sulfate is present in foods, beverages, and drinking water. Its reduction and concentration in the gut depend on the intestinal microbiome activity, especially sulfate-reducing bacteria (SRB), which can be involved in inflammatory bowel disease (IBD). Assimilatory sulfate reduction (ASR) is present in all living organisms. In this process, sulfate is reduced to hydrogen sulfide and then included in cysteine and methionine biosynthesis. In contrast to assimilatory sulfate reduction, the dissimilatory process is typical for SRB. A terminal product of this metabolism pathway is hydrogen sulfide, which can be involved in gut inflammation and also causes problems in industries (due to corrosion effects). The aim of the review was to compare assimilatory and dissimilatory sulfate reduction (DSR). These processes occur in some species of intestinal bacteria (e.g., Escherichia and Desulfovibrio genera). The main attention was focused on the description of genes and their location in selected strains. Their coding expression of the enzymes is associated with anabolic processes in various intestinal bacteria. These analyzed recent advances can be important factors for proposing possibilities of metabolic pathway extension from hydrogen sulfide to cysteine in intestinal SRB. The switch from the DSR metabolic pathway to the ASR metabolic pathway is important since toxic sulfide is not produced as a final product.
Bryostatins represent an important group of pharmaceutically promising substances. These compounds are produced by commensal microorganisms naturally occurring in marine invertebrates, mainly in bryozoans. The most frequently investigated substance is bryostatin-1, which is a highly oxygenated macrolide with a polyacetate backbone. The aim of this work was to summarize documented preclinical and clinical effects of bryostatin-class compounds. A literature search was made of Medline and Web of Science databases in 2012. Our review showed that bryostatins are potent agonists of protein kinase C. In addition to this, their significant antineoplastic activity against several tumor types has also been established and described. Bryostatin's anticancer activity has been proved against various cancer types. Moreover, significant results have been achieved by using bryostatin-1 in combination with other therapies, including combination with vaccine testing. Concerning other important properties that bryostatins possess, their ability to sensitize some resistant cells to chemotherapy agents, or immunoactivity and further stimulating growth of new neural connections, and enhancing effect on long-term memory are worth mentioning. In particular, some new bryostatin analogs could represent potential therapeutic agent for the treatment of cancer and other diseases in future.
Intestinal sulfate-reducing bacteria are often isolated from patients with inflammatory bowel disease, including ulcerative colitis, and can be involved in the development of gut inflammation. A comparison of the metabolism of intestinal sulfate-reducing bacteria isolated from individuals with colitis and healthy controls using statistical analysis has never been studied and described before. The aim of our research was to evaluate the parameters of dissimilatory sulfate reduction in Desulfovibrio species that were isolated from the feces of healthy objects and individuals with colitis. Principal component analysis indicates that the strains that were isolated from individuals with colitis grouped in the same cluster by biomass accumulation and sulfide production, same as the strains isolated from healthy individuals. Sulfate and lactate consumption measured over time showed negative correlation (Pearson correlations, p <0.01), healthy: -0.760; colitis: -0.770; healthy: -0.828; colitis: -0.847, respectively. The calculated linear regression (R 2 ) was lower in biomass accumulation and hydrogen sulfide production, 0.531; 0.625 respectively. Thus, biomass accumulation and sulfide production, together with measured kinetic parameters play an important factor in bowel inflammation, including ulcerative colitis. Additionally, acetate production can also synergize with H 2 S, while sulfate consumption and lactate oxidation likely represent minor factors in bowel disease.