Influence of the microbiota on epigenetics in colorectal cancer

Colorectal cancer is one of the most common malignancies and is the second leading cause of cancer death worldwide. Generally, there are three categories of colorectal cancer development mechanism—genetic, epigenetic and aberrant immunological signaling pathways—all of which may be initiated by an imbalanced gut microbiota. Epigenetic modifications enable host cells to change gene expression without modifying the gene sequence. The microbiota can interact with the host genome dynamically through the interface presented by epigenetic modifications. In particular, bacterially derived short-chain fatty acids have been identified as one clear link in the interaction of the microbiota with host epigenetic pathways. This review discusses recent findings relating to the cross talk between the microbiota and epigenetic modifications in colorectal cancer.     

用周丛原生动物群落监测水污染的研究

本文根据1983～1985年，用周丛原生动物群落对珠江广州河段、广州市内两个人工湖和广州市郊流溪水库等3种水体进行生物监测，通过分析周丛原生动物的群落结构特征．以及用模式识别法评价，识别这些水体的污染程度，并与1982年和1989年的研究结果对比，进一步说明不同污染类型水体的周丛原生动物的群落结构是稳定的，以及这两种方法对水污染的评价和识别是有效可行的．     

Phenolic profile of jujube fruit subjected to gut microbiota fermentation and its antioxidant potential against ethyl carbamate-induced oxidative damage

Objective: To evaluate the composition of bioactive substances and the antioxidant effects of jujube fruit under gut microbiota fermentation(GMF), and the inhibitory effect on cytotoxicity caused by ethyl carbamate(EC). Methods: Changes in the contents of flavonoids, polyphenols, total sugars, and reducing sugars of jujube fruit after GMF(0, 2, 6, 12, 24, and 48 h)were determined. The oxidation resistance of fermented jujube fruits(from 0 to 48 h fermentation) was evaluated using in vitro2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate)(ABTS) and ferric reducing antioxidant power(FRAP) assays. Inhibitory effects of 48 h-fermented jujube fruit at various concentrations(0.25, 0.50, 1.00, and 2.00 mg/m L) on EC-treated toxicity and DNA damage of Caco-2 cells were estimated using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2 H-tetrazolium bromide(MTT)and nuclear staining assays, respectively. Effects of different concentrations of jujube fruit on EC-treated Caco-2 cells' intracellular reactive oxygen species(ROS), glutathione(GSH) levels, and mitochondrial membrane potential(MMP) were also evaluated. Results: Jujube fruit has rich bioactive components after GMF and shows strong antioxidant capacity. Fermented jujube fruit can inhibit the cytotoxicity and DNA damage of Caco-2 cells caused by EC and reduce intracellular ROS generation, as well as restoring GSH and MMP. Conclusions: Fermented jujube fruit extracts produced by GMF still contain biologically active substances which retain biological activity and antioxidation capabilities.