Protective role of colitis in inflammatory arthritis via propionate-producing Bacteroides in the gut.

Objectives: To investigate whether and how inflammatory disease in the intestine influences the development of arthritis, considering that organ-to-organ communication is associated with many physiological and pathological events. Methods: First, mice were given drinking water containing dextran sodium sulfate (DSS) and then subjected to inflammatory arthritis. We compared the phenotypic symptoms between the cohoused and separately-housed mice. Next, donor mice were divided into DSS-treated and untreated groups and then cohoused with recipient mice. Arthritis was then induced in the recipients. The fecal microbiome was analyzed by 16S rRNA amplicon sequencing. We obtained type strains of the candidate bacteria and generated propionate-deficient mutant bacteria. Short-chain fatty acids were measured in the bacterial culture supernatant, serum, feces, and cecum contents using gas chromatography-mass spectrometry. Mice fed with candidate and mutant bacteria were subjected to inflammatory arthritis. Results: Contrary to expectations, the mice treated with DSS exhibited fewer symptoms of inflammatory arthritis. Intriguingly, the gut microbiota contributes, at least in part, to the improvement of colitis-mediated arthritis. Among the altered microorganisms, Bacteroides vulgatus and its higher taxonomic ranks were enriched in the DSS-treated mice. B. vulgatus, B. caccae, and B. thetaiotaomicron exerted anti-arthritic effects. Propionate production deficiency further prevented the protective effect of B. thetaiotaomicron on arthritis. Conclusions: We suggest a novel relationship between the gut and joints and an important role of the gut microbiota as communicators. Moreover, the propionate-producing Bacteroides species examined in this study may be a potential candidate for developing effective treatments for inflammatory arthritis.

Antibacterial activity of emulsions containing unsaturated fatty acid ergosterol esters synthesized by lipase-mediated transesterification.

Ergosterol, like cholesterol, has many beneficial physiological activities, and because it has no adverse clinical problem with cholesterol, it is a substance that can be used as a biomaterial in the food and cosmetics industry. However, ergosterol has low oil solubility and is easily crystallized, which is problematic for its direct use in the industry. This problem can be solved by combining fatty acids with ergosterol. In this study, ergosterol derivatives with unsaturated fatty acids were synthesized from ergosterol and various plant oils. Specifically, ergosterol oleate (EO), ergosterol linoleate (EL), and ergosterol linolenate (ELn) were synthesized using Proteus vulgaris K80 lipase. To effectively synthesize these unsaturated fatty acid ergosterol esters (FAEEs), 25 mM ergosterol and 40 mM plant oil were added into hexane solvent, and transesterification reaction was performed at 40 °C. Proteus vulgaris K80 lipase showed higher conversion yield than other commercial lipases, due to its high affinity to ergosterol and broad substrate specificity. Rapeseed oil, sunflower seed oil, and linseed oil were used to synthesize EO, EL, and ELn, respectively. The FAEEs were purified, and their purity was confirmed by FT-IR and LC-MS. The solubility of the FAEEs in a tricaprylin solvent was increased 11-16 times, compared to that of ergosterol. We found that EL- and ELn-containing emulsions had strong growth inhibitory activity against some dairy and cosmetic spoilage bacteria.

Characterization of Organic Solvent-Tolerant Lipolytic Enzyme from Marinobacter lipolyticus Isolated from the Antarctic Ocean.

The Antarctic marine environment provides a good source of novel lipolytic enzymes that possess beneficial properties, i.e., resistance to extreme physical and chemical conditions. We found a lipolytic Escherichia coli colony that was transformed using genomic DNA from Marinobacter lipolyticus 27-A9 isolated from the Antarctic Ross Sea. DNA sequence analysis revealed an open reading frame of lipolytic enzyme gene. The gene translates a protein (LipA9) of 404 amino acids with molecular mass of 45,247 Da. Recombinant LipA9 was expressed in E. coli BL21 (DE3) cells and purified by anion exchange and gel filtration chromatography. The kcat/Km of LipA9 was 175 s-1 µM-1, and the optimum temperature and pH were 70 °C and pH 8.0, respectively. LipA9 had quite high organic solvent stability; it was stable toward several common organic solvents up to 50% concentration. Substrate specificity studies showed that LipA9 preferred a short acyl chain length of p-nitrophenyl ester and triglyceride. Sequence analysis showed that LipA9 contained catalytic Ser72 and Lys75 in S-x-x-K motif, like family VIII esterases. Homology modeling and site-directed mutagenesis studies revealed that Tyr141 and Tyr188 residues were located near the conserved motif and played an important role in catalytic activity.

Cadaverine Production by Using Cross-Linked Enzyme Aggregate of Escherichia coli Lysine Decarboxylase.

Lysine decarboxylase (CadA) converts L-lysine into cadaverine (1,5-pentanediamine), which is an important platform chemical with many industrial applications. Although there have been many efforts to produce cadaverine through the soluble CadA enzyme or Escherichia coli whole cells overexpressing the CadA enzyme, there have been few reports concerning the immobilization of the CadA enzyme. Here, we have prepared a cross-linked enzyme aggregate (CLEA) of E. coli CadA and performed bioconversion using CadACLEA. CadAfree and CadACLEA were characterized for their enzymatic properties. The optimum temperatures of CadAfree and CadACLEA were 60°C and 55°C, respectively. The thermostability of CadACLEA was significantly higher than that of CadAfree. The optimum pH of both enzymes was 6.0. CadAfree could not be recovered after use, whereas CadACLEA was rapidly recovered and the residual activity was 53% after the 10th recycle. These results demonstrate that CadACLEA can be used as a potential catalyst for efficient production of cadaverine.