Evaluating the Transcriptomic and Metabolic Profile of Mice Exposed to Source Drinking Water

Transcriptomic and metabonomic methods were used to investigate mice’s responses to drinking source water (DSW) exposure. After mice were fed with DSW for 90 days, hepatic transcriptome was characterized by microarray and serum metabonome were determined by ¹H nuclear magnetic resonance (NMR) spectroscopy. A total of 243 differentially expressed genes (DEGs) were identified, among which 141 genes were up-regulated and 102 genes were down-regulated. Metabonomics revealed significant changes in concentrations of creatine, pyruvate, glutamine, lysine, choline, acetate, lipids, taurine, and trimethylamine oxide. Four biological pathways were identified by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis where both gene expression and metabolite concentrations were altered in response to DSW exposure. These results highlight the significance of combined use of transcriptomic and metabonomic approaches in evaluating potential health risk induced by DSW contaminated with various hazardous materials

Impact of Iron Precipitant on Toxicity of Arsenic in Water: A Combined in Vivo and in Vitro Study

Removing arsenic (As) from drinking water is widely dependent on iron (Fe)-based coagulation/flocculation techniques. However, little is known about the influence of Fe precipitant on As toxicity. In this present study, the influence of Fe on As toxicity was determined at systems biology level by in vitro and in vivo experiments. In vitro study based on HepG2 cell line found that Fe increased the As toxicity on cell viability and DNA damage, indicating the synergetic toxic effects. However, when the Fe and As were simultaneously exposed to mice by drinking water for 90 days, the results showed that Fe reduced the changes of hepatic transcriptomic profiles and serum and urine metabolic profiles caused by As exposure, showing the antagonistic toxic effects. The antagonistic effects might be because Fe reduced As bioavailability and accumulation, which was verified by As and Fe levels in feces and liver. The results of this study indicate that Fe precipitant can influence the As toxicity. The interactions between As and Fe and their bioavailability might play important roles in the As toxicity. When assessing the safety of As in drinking water, it is necessary to fully consider the combined effects of As and Fe

Phosphorus removal and sludge sampling for 16S rRNA gene pyrosequencing from the SBR performing EBPR.

<p>The pH of solution in the SBR was maintained at 7.2 ± 0.1 except at 60 d when accidentally overdosed acidic solution to decrease pH to 6.0 for around 20 h.</p

Venn diagram of conserved and unique genes for four Accumulibacter genomes of Clade IIC.

<p>Venn diagram of conserved and unique genes for four Accumulibacter genomes of Clade IIC.</p

Responses of Mouse Liver to Dechlorane Plus Exposure by Integrative Transcriptomic and Metabonomic Studies

Dechlorane plus (DP), a chlorinated flame retardant, has been widely detected in different environmental matrices and biota. However, toxicity data for DP have seldom been reported. In the present study, we investigated hepatic oxidative stress, DNA damage, and transcriptomic and metabonomic responses of male mice administered 500 mg/kg, 2000 mg/kg, and 5000 mg/kg of DP by gavage for 10 days. The results showed that DP exposure increased the level of superoxide dismutase (SOD) and 8-hydroxy-2-deoxyguanosine (8-OHdG). The microarray-based transcriptomic results demonstrated that DP exposure led to significant alteration of gene expression involved in carbohydrate, lipid, nucleotide, and energy metabolism, as well as signal transduction processes. The NMR-based metabonomic analyses corroborated these results showing changes of metabolites associated with the above altered mechanisms. Our results demonstrate that an oral exposure to DP can induce hepatic oxidative damage and perturbations of metabolism and signal transduction. These observations provide novel insight into toxicological effects and mechanisms of action of DP at the transcriptomic and metabonomic levels

Exploring the Shift in Structure and Function of Microbial Communities Performing Biological Phosphorus Removal

<div><p>A sequencing batch reactor fed mainly by acetate was operated to perform enhanced biological phosphorus removal (EBPR). A short-term pH shock from 7.0 to 6.0 led to a complete loss of phosphate-removing capability and a drastic change of microbial communities. 16S rRNA gene pyrosequencing showed that large proportions of glycogen accumulating organisms (GAOs) (accounted for 16% of bacteria) bloomed, including <i>Candidatus</i> Competibacter phosphatis and <i>Defluviicoccus</i>-related tetrad-forming organism, causing deteriorated EBPR performance. The EBPR performance recovered with time and the dominant <i>Candidatus</i> Accumulibacter (Accumulibacter) clades shifted from Clade IIC to IIA while GAOs populations shrank significantly. The Accumulibacter population variation provided a good opportunity for genome binning using a bi-dimensional coverage method, and a genome of Accumulibacter Clade IIC was well retrieved with over 90% completeness. Comparative genomic analysis demonstrated that Accumulibacter clades had different abilities in nitrogen metabolism and carbon fixation, which shed light on enriching different Accumulibacter populations selectively.</p></div

Characteristics of assembled scaffolds and the retrieved CAP IIC HKU-2 draft genome.

<p>Characteristics of assembled scaffolds and the retrieved CAP IIC HKU-2 draft genome.</p

Maximum likelihood phylogenetic tree of Accumulibacter <i>ppk1</i> gene sequences.

<p>The <i>ppk1</i> genes of the reconstructed Accumulibacter genomes are indicated in green, while those from clone library of sludges A and C are colored in orange. Seven and nine partial <i>ppk1</i> gene sequences with 99% identity were obtained from sludge A and C respectively. Reference sequences attached with their accession numbers are extracted from NCBI database. Node labels refer to bootstrap support values and <i>Rhodocyclus tenuis ppk1</i> gene is employed as the outgroup sequence.</p

The ANI and orthologous genes shared by each pair of Accumulibacter genomes.

<p>The ANI and orthologous genes shared by each pair of Accumulibacter genomes.</p

Relative abundances of <i>ppk1</i> genes of different clades in the microbial communities.

<p>The abundance of Accumulibacter was calculated according to the copy numbers of Accumulibacter and bacterial 16S rRNA genes by qPCR analysis. Meanwhile the 2 copies of <i>rrn</i> operon in CAP IIA UW-1 and 4 copies of <i>rrn</i> operon in the available bacterial finished genomes have been taken into account. The proportions of different <i>ppk1</i> genes in one sample was estimated by the copy numbers obtained from the qPCR assay using primer sets targeting <i>ppk1</i> genes of specific clades.</p