Effects of ferroferric oxide on propionate methanogenesis in sequencing batch reactors: Microbial community structure and metagenomic analysis.

This study investigated the effects of ferroferric oxide (Fe3O4) on propionate methanogenesis in anaerobic sequencing batch reactor (ASBR). Compared to ASBRC (without Fe3O4 addition), the addition of 10 g/L Fe3O4 (ASBRFe) decreased the maximum methane production rate by 69.6 % when propionate was used as the sole substrate. The addition of Fe3O4 reduced the contents of humic substances, riboflavin and nicotinamide adenine dinucleotide in extracellular polymeric substances. Therefore, Fe3O4 inhibited interspecies electron transfer of microorganisms through electronic mediators. Microbial community analysis revealed that Fe3O4 addition increased the relative abundance of acetate oxidizing bacterium (Mesotoga), but decreased the abundance of hydrogenotrophic methanogen (Methanobacterium). Further metagenomics analysis indicated that Fe3O4 increased the abundance of acetate oxidation genes and decreased that of hydrogenotrophic methanogenesis, quorum sensing and V/A-type ATPase genes. Thus, Fe3O4 reduced propionate methanogenesis during anaerobic digestion. The overall results indicate that Fe3O4 addition inhibits methanogenesis for treatment of propionate-contaminated wastewater in ASBR.

Social Media-Based Secondary Distribution of Human Immunodeficiency Virus/Syphilis Self-testing Among Chinese Men Who Have Sex with Men.

BACKGROUND: Social media and secondary distribution (distributing self-testing kits by indexes through their networks) both show strong promise to improve human immunodeficiency virus (HIV) self-testing uptake. We assessed an implementation program in Zhuhai, China, which focused on the secondary distribution of HIV/syphilis self-test kits among men who have sex with men (MSM) via social media. METHODS: Men aged ≥16 years, born biologically male, and ever had sex with another man were recruited as indexes. Banner ads on a social media platform invited the participants to apply for up to 5 self-test kits every 3 months. Index men paid a deposit of US$15/kit refundable upon submitting a photograph of a completed test result via an online submission system. They were informed that they could distribute the kits to others (referred to as "alters"). RESULTS: A total of 371 unique index men applied for 1150 kits (mean age, 28.7 [standard deviation, 6.9] years), of which 1141 test results were returned (99%). Among them, 1099 were valid test results; 810 (74%) were from 331 unique index men, and 289 tests (26%) were from 281 unique alters. Compared to index men, a higher proportion of alters were naive HIV testers (40% vs 21%; P < .001). The total HIV self-test reactivity rate was 3%, with alters having a significantly higher rate than indexes (5% vs 2%; P = .008). A total of 21 people (3%) had a reactive syphilis test result. CONCLUSIONS: Integrating social media with the secondary distribution of self-test kits may hold promise to increase HIV/syphilis testing coverage and case identification among MSM.

Polycyclic Aromatic Hydrocarbons in Urban Soils of Zhengzhou City, China: Occurrence, Source and Human Health Evaluation.

Increasing contamination of urban soil by persistent organic pollutants is a major environmental issue. The purpose of the present study was to investigate the distribution, source and human health risk of polycyclic aromatic hydrocarbons (PAHs) in different functional areas in Zhengzhou City, China. Total 130 soil samples were collected from surface layer (0-10 cm) in urban road, overpass, residential area and park in the city during January 2019. Concentrations of ∑PAH16 in the urban soil ranged from 49.90 to 11,565 µg kg-1 and seven carcinogenic PAHs accounted for 69% of the total PAHs. The mean concentrations of PAHs decreased in the following order: urban road > overpass > residential area > park. Analysis based on diagnostic rate demonstrated that PAHs mainly originated from pyrolysis sources including traffic emissions and combustion of coal and biomass. Health risk assessment indicated that PAHs in urban road in the city have potential carcinogenic risks to residents. The present study suggested that the control of urban PAHs pollution in Zhengzhou City should be strengthened.

Oral microbiome and risk of malignant esophageal lesions in a high-risk area of China: A nested case-control study.

OBJECTIVE: We aimed to prospectively evaluate the association of oral microbiome with malignant esophageal lesions and its predictive potential as a biomarker of risk. METHODS: We conducted a case-control study nested within a population-based cohort with up to 8 visits of oral swab collection for each subject over an 11-year period in a high-risk area for esophageal cancer in China. The oral microbiome was evaluated with 16S ribosomal RNA (rRNA) gene sequencing in 428 pre-diagnostic oral specimens from 84 cases with esophageal lesions of severe squamous dysplasia and above (SDA) and 168 matched healthy controls. DESeq analysis was performed to identify taxa of differential abundance. Differential oral species together with subject characteristics were evaluated for their potential in predicting SDA risk by constructing conditional logistic regression models. RESULTS: A total of 125 taxa including 37 named species showed significantly different abundance between SDA cases and controls (all P<0.05 & false discovery rate-adjusted Q<0.10). A multivariate logistic model including 11 SDA lesion-related species and family history of esophageal cancer provided an area under the receiver operating characteristic curve (AUC) of 0.89 (95% CI, 0.84-0.93). Cross-validation and sensitivity analysis, excluding cases diagnosed within 1 year of collection of the baseline specimen and their matched controls, or restriction to screen-endoscopic-detected or clinically diagnosed case-control triads, or using only bacterial data measured at the baseline, yielded AUCs>0.84. CONCLUSIONS: The oral microbiome may play an etiological and predictive role in esophageal cancer, and it holds promise as a non-invasive early warning biomarker for risk stratification for esophageal cancer screening programs.

Succession of fungal dynamics and their influence on physicochemical parameters during pig manure composting employing with pine leaf biochar.

The effects of pine leaf biochar (PLB) on fungal community during pig manure composting were investigated. Five different doses of PLB [0% (T1), 2.5% (T2), 5% (T3), 10% (T4) and 15% (T5)] were mixed with mixture of pig manure and sawdust (2:1) for 50 days of composting. The present results indicated that fungal diversity increased more obvious in biochar amendment treatments than control (T1) and that the highest was recorded in T4 treatment. Basidiomycota, Ascomycota and Mucoromycota were the most three abundant phyla in all the treatments, while Heterobasidion, Pezoloma, Mucor, Geastrum, Talaromyces and Cystofilobasidium were the richness genera. In addition, network analysis indicated that fungal community abundance was significantly (p < 0.05) associated with temperature, pH, CO2 and CH4 emission and the seed germination index. In summary, the 10% PLB amendment (T4) was a potential option to strengthen fungal diversity and improve the composting efficiency as well as compost quality.

Status, sources, and risk assessment of polycyclic aromatic hydrocarbons in urban soils of Xi'an, China.

To identify status, source of polycyclic aromatic hydrocarbons (PAHs) in urban soils and to assess soil environmental quality in Xi'an City, China, total 45 soil samples were collected from surface layer (0-10 cm) in different functional areas. Total concentrations of 16 US EPA priority PAHs ranged from 149.9 to 5770 µg kg-1, with a mean of 1246 µg kg-1. High molecular weight (HMW) PAHs accounted for the majority (42.4-72.2%) of the total PAHs in the urban soils, and phenanthrene (Phe), fluorene (Flo), pyrene (Pyr), benzo(b)fluoranthene (BbF), and chrysene (Chr) were the major compounds. Concentrations of PAHs varied among different functional areas. High level of PAHs was particularly apparent in industrial zones and city road overpass, while low level was recorded in scenic spots and campus. The integration of isomer ratios, principal component analysis (PCA), and positive matrix factor (PMF) indicated that the sources of PAHs in Xi'an urban soils were mainly derived from vehicle emissions and coal combustion. Based on incremental lifetime cancer risks (ILCR) model, the urban soils from the three functional areas (industrial zone, urban road, and city road overpass) posed potential cancer risk, and the cancer risks of direct ingestion for children were apparently higher than that for adolescence and for adult, respectively. Therefore, attention should be paid to the health risk for children exposed to PAHs in the urban soils.

Residuals, bioaccessibility and health risk assessment of PAHs in winter wheat grains from areas influenced by coal combustion in China.

Polycyclic aromatic hydrocarbons (PAHs) contamination in atmospheric and soil was serious, which is mainly due to high level of emission of PAHs in China resulted from the predominating use of coal in energy consumption and continuous development of economy and society for years. However, the status of PAHs in winter wheat grains from the areas influenced by coal combustion in China was still not clear. During harvest season, the winter wheat grains were collected from agricultural fields surrounding coal-fired power plants located in Shaanxi and Henan Provinces. This study found that the mean concentrations of 15 priority PAHs ranged from 69.58 to 557.0µgkg-1. Three-ring PAHs (acenaphthene, acenaphthylene, fluorene, phenanthrene and anthracene) were dominant in the grains, accounting for approximately 70-81% of the total PAHs. The bioaccessibility of low molecular weight (LMW, 2-3 ring) PAHs (51.1-52.8%), high molecular weight (HMW, 4-6 ring) PAHs (19.8-27.6%) and total PAHs (40.9-48.0%) in the intestinal condition was significantly (p<0.001) higher than that (37.4-38.6%; 15.6-22.5%; 30.7-35.5%) in the gastric condition, respectively. Based on total PAHs, the values of incremental lifetime cancer risk (ILCR) for children, adolescents, adults and seniors were all higher than the baseline value (10-6) and some even fell in the range of 10-5-10-4, which indicated that most grains from the areas affected by coal combustion possessed considerable cancer risk. The present study also indicated that the children were the age group most sensitive to PAHs contamination. The pilot research provided relevant information for the regulation of PAHs in the winter wheat grains and for the safety of the agro-products growing in the PAHs-contaminated areas.