An Evaluation Method of Human Gut Microbial Homeostasis by Testing Specific Fecal Microbiota

Research on microecology has been carried out with broad perspectives in recent decades,which has enabled a better understanding of the gut microbiota and its roles in human health and disease.It is of great significance to routinely acquire the status of the human gut microbiota;however,there is no method to evaluate the gut microbiome through small amounts of fecal microbes.In this study,we found ten predominant groups of gut bacteria that characterized the whole microbiome in the human gut from a large-sample Chinese cohort,constructed a real-time quantitative polymerase chain reaction(qPCR)method and developed a set of analytical approaches to detect these ten groups of predominant gut bacterial species with great maneuverability,efficiency,and quantitative features.Reference ranges for the ten predominant gut bacterial groups were established,and we found that the concentration and pairwise ratios of the ten predominant gut bacterial groups varied with age,indicating gut microbial dysbiosis.By comparing the detection results of liver cirrhosis(LC)patients with those of healthy control subjects,differences were then analyzed,and a classification model for the two groups was built by machine learning.Among the six established classification models,the model established by using the random forest algorithm achieved the highest area under the curve(AUC)value and sensitivity for predicting LC.This research enables easy,rapid,stable,and reliable testing and evaluation of the balance of the gut microbiota in the human body,which may contribute to clinical work.

Thiocyanate Oxidation by Coculture from a Coke Wastewater Treatment Plant

Bacterial strains in an activated sludge aerobic reactor from a coke wastewater were found to be able to utilize thiocyanate as carbon source when the thiocyanate-containing wastewater was deprived of carbon source. This study showed that three thiocyanate-oxidizing bacterial strains, Burkholderia sp., Chryseobacterium sp., and Ralstonia sp. were isolated from the activated sludge of a coke wastewater treatment plant as evidenced by the fact that complete decomposition of thiocyanate was achieved either by coculture or individual pure culture. The thiocyanate biodegradation by the coculture occurred with an optimal pH range between 6.5 and 8.5 and an optimal temperature range between 30°C and 40°C. The biodegradation kinetics of thiocyanate was well fitted with the Andrew-Haldane model, which demonstrated a distinct substrate concentration-inhibited bacterial growth pattern. The effects of different types of additional carbon, nitrogen or sulfur sources on thiocyanate biodegradation were also investigated. Analysis of the end-products indicated that thiocyanate degradation by these strains should proceed via two pathways.