Research progress of gut flora in improving human wellness

Human wellness is the ultimate goal of our efforts in improving the human life.Special foods are undoubtedly important in achieving human wellness.However,overeating significantly leads to obesity and diabetes.These chronic diseases will in turn affect the human wellness.Therefore,“dietary restriction and proper exercise”were introduced in the human daily life.Different foods cause various effects on the human health.The diversification of diet is a priority for nutritionists to keep our body healthy.To avoid diabetes mellitus,special foods for ketogenic diet,low-carbon diet,and low-calorie intake are also gradually attracting attention.In addition,the hypothesis that“hunger sensation comes from gut flora”brings new light to the research on the biological motivation for humans to eat food.This hypothesis has been gradually demonstrated using the flexible fasting technology by providing special foods,such as plant polysaccharides and dietary fibers.The response to food-needing signals from the gut flora to these foods demonstrates the importance of the gut flora in improving human wellness.The gut flora is probably an essential factor for translating the food-eating signals and converting the nutrition to our body.Therefore,“gut flora priority principle”is developed to guarantee human wellness.The 16S rRNA sequencing and mass spectrometric techniques can be used to identify the gut flora,which may guide us to a new era of human wellness based on gut flora wellness.

Occurrence and distribution of phthalate esters (PAEs) in wetland sediments

This study investigated the occurrence and distribution of 15 phthalate esters (PAEs) in sediments collected from Qixinghe wetlands, northeast China. Total concentration of PAEs in all sediments ranged from 128.41 to 502.79 mu g kg(-1), with the mean value of 284.61 mu g kg(-1). PAEs significantly differed among wetland types; the average PAEs concentration of surface sediments were as follows: Phragmites australis wetland (PAW, 419.87 +/- 73.61 mu g kg(-1)) > Carex lasiocarpa wetland (CLW, 304.18 +/- 56.47 mu g kg(-1)) > Deyeuxia angustifolia wetland (DAW, 129.78 +/- 18.24 mu g kg(-1)). Dimethyl phthalate (DMP), diisobutyl phthalate, di-n-butyl phthalate, and di-(2-ethylhexyl) phthalate (DEHP) were found in all sediments, DEHP was the most abundant PAEs congeners with concentrations varying from 37.62 to 294.9 mu g kg(-1). DMP and DEHP exhibited relatively higher concentrations in CLW and PAW wetlands than in DAW, indicating that the different deoxidization and biodegradation conditions could have important implications for the distribution patterns of PAEs in wetland sediments. The variation of PAEs concentrations in horizontal and vertical sediments with wetland types could be attributed to the migration of contaminants by surface water, groundwater and atmospheric deposition. The occurrence and distribution of PAEs in wetlands also suggests that contamination in natural ecosystems should not be overlooked.

Effects of ferrous and manganese ions on anammox process in sequencing batch biofilm reactors

Ferrous and manganese ions, as essential elements, significantly affect the synthesis of Haem-C, which participates in the energy metabolism and proliferation of anammox bacteria. In this study, two identical sequencing batch biofilm reactors were used to investigate the effects of ferrous and manganese ions on nitrogen removal efficiency and the potential of metal ions serving as electron donor/acceptors in the anammox process. Fluorescence in situ hybridization analysis was applied to investigate the microbial growth. Results showed that the nitrogen removal increased at high concentrations of Fe2＋ and Mn2＋ and the maximum removal efficiency was nearly 95% at Fe2＋ 0.08 mmol/L and Mn2＋ 0.05 mmol/L, which is nearly 15% and 8% higher than at the lowest Fe2＋ and Mn2＋ concentrations （0.04 and 0.0125 mmol/L）. The stabilities of the anammox reactor and the anammox bacterial growth were also enhanced with the elevated Fe2＋ and Mn2＋ concentrations. The Fe2＋ and Mn2＋were consumed by anammox bacteria along with the removal of ammonia and nitrite. Stoichiometry analysis showed Fe2＋ could serve as an electron donor for NO3-N in the anammox process. Nitrate could be reduced with Fe2＋ serving as the electron donor in the anammox system, which causes the value of NO^-N/NH4-N to decrease with the increasing of N-removal efficiency.

Occurrence and fate of typical antibiotics in wastewater treatment plants in Harbin, North-east China

As a new pollutant, antibiotics in the environment and their removal in wastewater treatment plants (WWTPs) have gained considerable attention. However, few studies investigated antibiotics in the north-eastern areas of China. By employing high-performance liquid chromatography-tandem mass spectrometry, the concentration distribution and removal of 12 antibiotics belonging to four types (cephalosporins, sulfonamides, fluoroquinolones, and macrolides) were investigated in influents and effluents as well as the removal efficiencies of four typical treatment processes in 18 wastewater treatment plants of Harbin City, north-eastem China. Macrolides and fluoroquinolones presented relatively higher detection concentrations and rates both in the water and in the sludge phases. Sulfonamides and cephalosporins displayed higher detection concentrations in the water phase. The representative antibiotics in influents and effluents included ROX, NOR, OFL, SMX, AZI, and CLA, with detection rates above 95%. The detection rates of the other six antibiotics exceeded 30%. In the sludge, the other five antibiotics, except SMX, presented relatively higher detection concentrations and rates, with detection rates greater than 95%. For cephalosporin, the detection rates of CTX and CFM in the sludge were 0. The removal efficiencies for the 12 antibiotics differed greatly, with average values ranging from 30% to 80% and the highest values for cephalosporin. The removal of antibiotics did not differ significantly among the four different treatment processes.

Community diversity and distribution of ammonia-oxidizing archaea in marsh wetlands in the black soil zone in North-east China

Since its first detection, ammonia-oxidizing archaea (AOA) have been proven to be ubiquitous in aquatic and terrestrial ecosystems. In this study, two freshwater marsh wetlands- the Honghe wetland and Qixinghe wetland - in the black soil zone in North-east China were chosen to investigate the AOA community diversity and distribution in wetland soils with different vegetation and depth. In the Honghe wetland, two sampling locations were chosen as the dominant plant transited from Deyeuxia to Carex. In the Qixinghe wetland, one sample location that was dominated by Deyeuxia was chosen. Samples of each location were collected from three different depths, and Illumina MiSeq platform was used to generate the AOA amoA gene archive. The results showed that the AOA amoA genes in the soils of the two wetlands were affiliated with three lineages: Nitrososphaera, Nitrosotalea, and Nitrosopumilus clusters. The different dominant status of these AOA lineages indicated their differences in adapting to acidic habitat, oxygenic/hypoxic alternation, organic matter, and other environmental factors, suggesting high diversity among AOA in marsh soils. The main driver of the AOA community was pH, along with organic carbon and ammonium nitrogen, which also played an important role combined with many other environmental factors. Thus, soil physiochemical characteristics, rather than vegetation, were the main cause of AOA community diversity in the wetlands in the black soil zone in China.

Current molecular biologic techniques for characterizing environmental microbial community

Microbes are vital to the earth because of their enormous numbers and instinct function maintaining the natural balance. Since the microbiology was applied in environmental science and engineering more than a century ago, researchers desire for more and more information concerning the microbial spatio-temporal variations in almost every fields from contaminated soil to wastewater treatment plant （WWTP）. For the past 30 years, molecular biologic techniques explored for environ- mental microbial community （EMC） have spanned a broad range of approaches to facilitate the researches with the assistance of computer science： faster, more accurate and more sensitive. In this feature article, we outlined several current and emerging molecular biologic techniques applied in detection of EMC, and presented and assessed in detail the application of three promising tools.

Anaerobic ammonia oxidizing bacteria： ecological distribution, metabolism, and microbial interactions

Anammox （ANaerobic AMMonia OXidation） is a newly discovered pathway in the nitrogen cycle. This discovery has increased our knowledge of the global nitrogen cycle and triggered intense interest for anammox-based applications. Anammox bacteria are almost ubiquitous in the suboxic zones of almost all types of natural ecosystems and contribute significant to the global total nitrogen loss. In this paper, their ecological distributions and contributions to the nitrogen loss in marine, wetland, terrestrial ecosystems, and even extreme environments were reviewed. The unique metabolic mechanism of anammox bacteria was well described, including the particular cellular structures and genome compositions, which indicate the special evolutionary status of anammox bacteria. Finally, the ecological interactions among anammox bacteria and other organisms were discussed based on substrate availability and spatial organizations. This review attempts to summarize the fundamental understanding of anammox, provide an up-to-date summary of the knowledge of the overall anammox status, and propose future prospects for anammox. Based on novel findings, the metagenome has become a powerful tool for the genomic analysis of communities containing anammox bacteria; the metabolic diversity and biogeochemistry in the global nitrogen budget require more comprehensive studies.

Seasonal variations in the concentration and removal of nonylphenol ethoxylates from the wastewater of a sewage treatment plant

In this study, we investigated the occurrence and fate of nonylphenol（NP）, nonylphenol monoethoxylate（NP1EO） and nonylphenol diethoxylate（NP2EO） in a full scale sewage treatment plant, which applied an Anaerobic/Oxic process. Concentrations of NP, NP1 EO and NP2 EO in the wastewater were measured during the period spanning a whole year.The results showed remarkable seasonal variation in the concentrations of the compounds.The NPn EO compounds were most abundant in winter, with the total concentrations of influent NP, NP1 EO and NP2 EO ranging from 3900 to 7000 ng/L, 4000 to 4800 ng/L and 5200 to 7200 ng/L, respectively. Regarding the total removal efficiencies of the three types of short-chain NPn EO compounds, different trends were exhibited according to different seasons. The average removal efficiency of NP for the different seasons ranked as follows：winter 〉 summer 〉 autumn 〉 spring; NP2 EO concentrations decreased as follows： summer 〉autumn 〉 winter 〉 spring, while NP1 EO concentrations reduced according to： spring 〉summer 〉 autumn 〉 winter. We also investigated the contribution ratio of individual treatment units in the A/O process, with the findings suggesting that the anaerobic treatment unit plays an important role in the elimination of short-chain NPn EOs from the wastewater.

Efects of idle time on biological phosphorus removal by sequencing batch reactors

Three identical sequencing batch reactors （SBRs） were operated to investigate the effects of various idle times on the biological phosphorus （P） removal. The idle times were set to 3 hr （R1）, 10 hr （R2） and 17 hr （R3）. The results showed that the idle time of a SBR had potential impact on biological phosphorus removal, especially when the influent phosphorus concentration increased. The phosphorus removal efficiencies of the R2 and R3 systems declined dramatically compared with the stable R1 system, and the Prelease and P-uptake rates of the R3 system in particular decreased dramatically. The PCR-DGGE analysis showed that uncultured Pseudomonas sp. （GQ183242.1） and β-Proteobacteria （AY823971） were the dominant phosphorus removal bacteria for the R1 and R2 systems, while uncultured γ-Proteobacteria were the dominant phosphorus removal bacteria for the R3 system. Glycogen-accumulating organisms （GAOs）, such as uncultured Sphingomonas sp. （AM889077）, were found in the R2 and R3 systems. Overall, the R1 system was the most stable and exhibited the best phosphorus removal efficiency. It was found that although the idle time can be prolonged to allow the formation of intracellular polymers when the phosphorus concentration of the influent is low, systems with a long idle time can become unstable when the influent phosphorus concentration is increased.

N_2O emission from nitrogen removal via nitrite in oxic-anoxic granular sludge sequencing batch reactor

Bionitrification is considered to be a potential source of nitrous oxide （N2O） emissions, which are produced as a by-product during the nitrogen removal process. To investigate the production of N2O during the process of nitrogen removal via nitrite, a granular sludge was studied using a labscale sequence batch reactor operated with real-time control. The total production of N2O generated during the nitrification and denitrification processes were 1.724 mg/L and 0.125 mg/L, respectively, demonstrating that N2O is produced during both processes, with the nitrification phase generating larger amount. In addition, due to the NEO-N mass/oxidized ammonia mass ratio, it can be concluded that nitrite accumulation has a positive influence on N2O emissions. Results obtained from PCRDGGE analysis demonstrate that a specific Nitrosomonas microorganism is related to N2O emission.

A novel strategy for a reinforced anammox process with iron-modified Enteromorpha prolifera biochar

Modified biochar with higher electron transport and adsorption capabilities could significantly improve the performance of anaerobic ammonia oxidation(anammox).However,there are few related investigations on the reinforcement of anammox through iron-modified Enteromorpha prolifera biochar(IMEPB).In this study,with the addition of the IMEPB in the anammox system,the enhancing process of anammox performance was studied,the improving feasibility of anammox was evaluated,and the reinforcing mechanism of anammox was elucidated.The results showed that the optimal iron−charcoal ratio(Fe:C)and IMEPB dosage were 1:10 and 10 g L^(−1),respectively.Under the optimal conditions,when the nitrogen loading rate gradually increased to 0.557(kg m^(−3) day^(−1)),the nitrogen removal efficiency and nitrogen removal rate of the anammox process supplemented with IMEPB increased by 11%,and the specific anammox activity increased by 23.8%.Compared with the control,the secretion of extracellular polymeric substances(EPS)of anammox bacteria supplemented IMEPB increased by 24.4%,greatly improving the stability of the anammox system.Meanwhile,EPS secretion further promoted the microbial activity of anammox bacteria,achieving a 19%increase in the abundance of Candidatus Brocadia.These findings demonstrate the potential mechanism of IMEPB in improving anammox,provide new insights into recycling E.prolifera,and provide a novel reinforcement strategy for anammox.In the future,adding IMEPB may be a vital measure for the practical application of anammox in coastal areas.