Dual engineered bacteria improve inflammatory bowel disease in mice.

Currently, there are many different therapies available for inflammatory bowel disease (IBD), including engineered live bacterial therapeutics. However, most of these studies focus on producing a single therapeutic drug using individual bacteria, which may cause inefficacy. The use of dual drugs can enhance therapeutic effects. However, expressing multiple therapeutic drugs in one bacterial chassis increases the burden on the bacterium and hinders good secretion and expression. Therefore, a dual-bacterial, dual-drug expression system allows for the introduction of two probiotic chassis and enhances both therapeutic and probiotic effects. In this study, we constructed a dual bacterial system to simultaneously neutralize pro-inflammatory factors and enhance the anti-inflammatory pathway. These bacteria for therapy consist of Escherichia coli Nissle 1917 that expressed and secreted anti-TNF-α nanobody and IL-10, respectively. The oral administration of genetically engineered bacteria led to a decrease in inflammatory cell infiltration in colon and a reduction in the levels of pro-inflammatory cytokines. Additionally, the administration of engineered bacteria did not markedly aggravate gut fibrosis and had a moderating effect on intestinal microbes. This system proposes a dual-engineered bacterial drug combination treatment therapy for inflammatory bowel disease, which provides a new approach to intervene and treat IBD. KEY POINTS: • The paper discusses the effects of using dual engineered bacteria on IBD • Prospects of engineered bacteria in the clinical treatment of IBD.

[Washing copper (II)-contaminated soil using surfactant solutions].

The batch equilibrium washing of copper (II) in the soil matrix by anionic surfactant, sodium dodecylbenzyl sulfonate (SDBS), nonionic surfactant, octylphenoxypolyethoxyethanol (TX100), and their mixture (SDBS-TX100), was studied and compared. The influences of surfactant concentrations, washing time, pH values of solutions, ratios of soil to water and inorganic salts on washing efficiency were investigated. It was shown that the washing efficiency differed with the kinds of surfactants. Given the initial surfactant concentrations, the washing of copper (II) by single SDBS was greater than those by single TX100 and the mixed SDBS-TX100. The washing efficiency by 6 000 mg x L(-1) of SDBS was up to 46.3%, which was 5.8, 10.8, 10.8 and 19.3 times as those by SDBS-TX100 (3:1), SDBS-TX100 (1:1), SDBS-TX100 (1:3) and single TX100 respectively. When the ratio of soil to water was 1 to 10 and washing time reached 24 h, the washing efficiency achieved the maximum. pH values of solutions had obvious effect on the washing of copper (II). The washing efficiency of copper decreased sharply with the increase of pH. At the high acidity (pH = 1.50), the washing efficiency of copper (II) was up to 95%. The smaller the ratios of soil to water were, the higher the washing efficiencies would be. The existence of inorganic salts with the certain concentrations, such as Na+, Ca2+ and Mg2+, could not influence the washing capacity of surfactants, but the excessive Mg2+ (more than 500 mg x L(-1)) could resulted in the precipitation of SDBS. The results will make an implication for surfactant-enhanced remediation of soils contaminated with heavy metals.