Nitrogen removal performance and microbiological characteristics of a three-stage series of vertical flow constructed wetlands.

In this study, the treatment performance and underlying molecular mechanisms of nitrogen transformation in a three-stage series of vertical flow constructed wetlands (T-VFCWs) treating rural domestic sewage were investigated at three different hydraulic loading rates (HLRs). Specifi-cally, the T-VFCWs composed of three sequential vertical flow constructed wetlands (termed V-1, V-2 and V-3), which were built according to the topography. The results showed that high pollutant removal rates could be achieved when the T-VFCWs was operated to treat rural domestic sewage, even though the HLR increased from 0.10 to 0.20 m3·m-2·d-1. Effluent quality of the T-VFCWs could reach Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002) class A standard. Regarding to the T-VFCWs operated under the oxygen-limiting conditions, three different pathways for nitrogen transformation could be respectively formed in V-1, V-2 and V-3, owing to the specific influent quality of each subunit. Consequently, the T-VFCWs were effective in nitrogen removal as a result of the collaboration of the three subunits. When the T-VFCWs ran constantly during the test, nitrogen removal in V-1, V-2, and V-3 respectively relied on the nitritation/denitrification process, the completely autotrophic nitrogen removal over nitrite (CANON) process, and the denitrification process. The contributions of three subunits for total nitrogen (TN) and NH4+-N removal were (51.3±4.4)% and (63.7±2.6)%, (30.9±4.8)% and (35.5±4.5)%, (17.8±5.0)% and (0.8±0.1)%, respectively. This study could provide scientific basis and technical support for the research and the engineering application of hybrid constructed wetlands.

Analysis of prognostic genes in the tumor microenvironment of lung adenocarcinoma.

BACKGROUND: Prognostic genes in the tumor microenvironment play an important role in immune biological processes and the response of cancer to immunotherapy. Thus, we aimed to assess new biomarkers that are associated with immune/stromal cells in lung adenocarcinomas (LUAD) using the ESTIMATE algorithm, which also significantly affects the prognosis of cancer. METHODS: The RNA sequencing (RNA-Seq) and clinical data of LUAD were downloaded from the the Cancer Genome Atlas (TCGA ). The immune and stromal scores were calculated for each sample using the ESTIMATE algorithm. The LUAD gene chip expression profile data and the clinical data (GSE37745, GSE11969, and GSE50081) were downloaded from the Gene Expression Omnibus (GEO) for subsequent validation analysis. Differentially expressed genes were calculated between high and low score groups. Univariate Cox regression analysis was performed on differentially expressed genes (DEGs) between the two groups to obtain initial prognosis genes. These were verified by three independent LUAD cohorts from the GEO database. Multivariate Cox regression was used to identify overall survival-related DEGs. UALCAN and the Human Protein Atlas were used to analyze the mRNA /protein expression levels of the target genes. Immune cell infiltration was evaluated using the Tumor Immune Estimation Resource (TIMER) and CIBERSORT methods, and stromal cell infiltration was assessed using xCell. RESULTS: In this study, immune scores and stromal scores are significantly associated with the clinical characteristics of LUAD, including T stage, M stage, pathological stage, and overall survival time. 530 DEGs (18 upregulated and 512 downregulated) were found to coexist in the difference analysis with the immune scores and stromal scores subgroup. Univariate Cox regression analysis showed that 286 of the 530 DEGs were survival-related genes (p < 0.05). Of the 286 genes initially identified, nine prognosis-related genes (CSF2RB, ITK, FLT3, CD79A, CCR4, CCR6, DOK2, AMPD1, and IGJ) were validated from three separate LUAD cohorts. In addition, functional analysis of DEGs also showed that various immunoregulatory molecular pathways, including regulation of immune response and the chemokine signaling pathways, were involved. Five genes (CCR6, ITK, CCR4, DOK2, and AMPD1) were identified as independent prognostic indicators of LUAD in specific data sets. The relationship between the expression levels of these genes and immune genes was assessed. We found that CCR6 mRNA and protein expression levels of LUAD were greater than in normal tissues. We evaluated the infiltration of immune cells and stromal cells in groups with high and low levels of expression of CCR6 in the TCGA LUAD cohort. In summary, we found a series of prognosis-related genes that were associated with the LUAD tumor microenvironment.

Novel immune subtypes of lung adenocarcinoma identified through bioinformatic analysis.

The magnitude of the immune response is closely associated with clinical outcome in patients with cancer. However, finding potential therapeutic targets for lung cancer in the immune system remains challenging. Here, we constructed a vital immune-prognosis genes (VIPGs) based cluster of lung adenocarcinoma (LUAD) from IMMPORT databases and The Cancer Genome Atlas. A transcription factor regulatory network for the VIPGs was also established. The tumor microenvironment of LUAD was analyzed using the ESTIMATE (Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data) algorithm and single-sample Gene Set Enrichment Analysis. The immune checkpoints and genomic alterations were explored in the different immune clusters. We identified 15 VIPGs for patients with LUAD and clustered the patients into low-immunity and high-immunity subtypes. The immune score, stromal score and ESTIMATE score were significantly higher in the high-immunity subtype, whereas tumor purity was higher in the low-immunity subtype. In addition, the immune checkpoints cytotoxic T lymphocyte associate protein-4(CTLA4), programmed cell death protein-1 and programmed death-ligand were elevated in the low-immunity subtype. The genomic results also showed that the tumor mutation burden was higher in the high-immunity subtype. Finally, Gene Set Enrichment Analysis showed that several immune-related gene sets, including interleukin-2/STAT5 signaling, inflammatory response, interleukin-6/Janus kinase(JAK)/signal transducer and activator of transcription 3 (STAT3) signaling, interferon-gamma response and allograft rejection, were elevated in the high-immunity subtype. Finally, high-immunity patients exhibited greater overall and disease-specific survival outcome compared with low-immunity patients (log rank P = 0.013 and P = 0.0097). Altogether, here we have identified 15 immune-prognosis genes and a potential immune subtype for patients with LUAD, which may provide new insights into the prognosis and treatment of LUAD.