Identification and degradation of structural extracellular polymeric substances in waste activated sludge via a polygalacturonate-degrading consortium.

By maintaining the cell integrity of waste activated sludge (WAS), structural extracellular polymeric substances (St-EPS) resist WAS anaerobic fermentation. This study investigates the occurrence of polygalacturonate in WAS St-EPS by combining chemical and metagenomic analyses that identify ∼22% of the bacteria, including Ferruginibacter and Zoogloea, that are associated with polygalacturonate production using the key enzyme EC 5.1.3.6. A highly active polygalacturonate-degrading consortium (GDC) was enriched and the potential of this GDC for degrading St-EPS and promoting methane production from WAS was investigated. The percentage of St-EPS degradation increased from 47.6% to 85.2% after inoculation with the GDC. Methane production was also increased by up to 2.3 times over a control group, with WAS destruction increasing from 11.5% to 28.4%. Zeta potential and rheological behavior confirmed the positive effect which GDC has on WAS fermentation. The major genus in the GDC was identified as Clostridium (17.1%). Extracellular pectate lyases (EC 4.2.2.2 and 4.2.2.9), excluding polygalacturonase (EC 3.2.1.15), were observed in the metagenome of the GDC and most likely play a core role in St-EPS hydrolysis. Dosing with GDC provides a good biological method for St-EPS degradation and thereby enhances the conversion of WAS to methane.

Genome-wide DNA methylation patterns in monocytes derived from patients with primary Sjogren syndrome / 中华医学杂志(英文版)

BACKGROUND@#Epigenetics, especially DNA methylation, plays an important role in the pathogenesis of primary Sjogren syndrome (pSS). Our study aimed to reveal the role of DNA methylation in peripheral monocytes of pSS patients.@*METHODS@#A total of 11 pSS patients and five age-matched healthy controls (HCs) were included in this study. Monocytes were isolated from peripheral blood mononuclear cells using magnetic microbeads. DNA methylation profiles were generated using Human Methylation 850K BeadChips.@*RESULTS@#In monocytes from pSS patients, we identified 2819 differentially methylated positions (DMPs), comprising 1977 hypomethylated- and 842 hypermethylated-DMPs, corresponding to 1313 unique genes when compared with HCs. IFI44L, MX1, PAARP9, and IFITM1, which influence the interferon (IFN) signaling pathway, were among the genes hypomethylated in pSS. Functional analysis of genes with a minimum of two DMPs showed involvement in antigen binding, transcriptional regulation, cell adhesion, IFN-γ pathway, type I IFN pathway, antigen presentation, Epstein-Barr virus infection, human T-lymphotropic virus type 1 virus infection, and metabolic disease-related pathways. In addition, patients with higher serum IgG levels exhibited enrichment in Notch signaling and metabolic-related pathways. Upon comparing monocytes with salivary gland epithelial cells, an important overlap was observed in the cell cycle, cell senescence, and interleukin-17 signaling pathways. The differentially methylated genes were more enriched in the ribosome- and AMP-activated protein kinase signaling pathway in anti-Ro/SSA and anti-La/SSB autoantibodies double-positive patients.@*CONCLUSION@#Genome-wide DNA methylation profiling revealed significant differences in DNA methylation in monocytes isolated from patients with pSS.