Enhanced electron transfer for the improvement of nitrogen removal efficiency and NO reduction at low temperatures.

Low temperature generally restricts biological activity, slowing down electron transfer in biogeochemical cycles and causing a series of environmental problems such as nitrogen pollution. We present a strategy to boost electron transfer in microbial cell at low temperatures via stimulation with low current. It is demonstrated by establishing a constructed wetland system coupled with solar powered microbial electrolysis cell, which enhances microbial activity through external micro currents (18.

Exploring the mechanisms of Qingdu Fang for the treatment of cervical HR-HPV using UPLC-QTOF-MS, network pharmacology, and cell experimentation.

Qingdu Fang (QDF) is a traditional Chinese herbal formula with remarkable clinical effect in the treatment of HR-HPV, but its mechanism remains unclear. In this study, UPLC-QTOF-MS was used to detect its components, network pharmacology was used to explore the traditional Chinese medicine monomers and their related targets for the treatment of HR-HPV in QDF. Molecular docking and experiments were performed to verify the results.

Diverse metabolism drives comammox in continental-scale agricultural streams: Important ammonia oxidation but low NO production.

Agriculture receives approximately 25 % of the annual global nitrogen input, 37 % of which subsequently runs off into adjacent low-order streams and surface water, where it may contribute to high nitrification and nitrous oxide (NO). However, the mechanisms of nitrification and the pathways controlling NO production in agricultural streams remain unknown. Here, we report that the third microbial ammonia oxidation process, complete ammonia oxidation (comammox), is widespread and contributes to important ammonia oxidation with low ammonia-NO conversion in both basin- and continental-scale agricultural streams.

Ammonium-derived nitrous oxide is a global source in streams.

Global riverine nitrous oxide (NO) emissions have increased more than 4-fold in the last century. It has been estimated that the hyporheic zones in small streams alone may contribute approximately 85% of these NO emissions. However, the mechanisms and pathways controlling hyporheic NO production in stream ecosystems remain unknown.

Effect of tillage state of paddy soils with heavy metal pollution on the nosZ gene of NO reductase.

Paddy soils are an important source of atmospheric nitrous oxide (NO). However, numerous studies have focused on NO production during the soil tillage period, neglecting the NO production during the dry fallow period. In this study, we conducted an incubation experiment using the acetylene inhibition technique to investigate NO emission and reduction rates of paddy soil profiles (0-1 m) from Guangdong Province and Jinlin Province in China, with different heavy-metal pollution levels.

Hot moment of NO emissions in seasonally frozen peatlands.

Since the start of the Anthropocene, northern seasonally frozen peatlands have been warming at a rate of 0.6 °C per decade, twice that of the Earth's average rate, thereby triggering increased nitrogen mineralization with subsequent potentially large losses of nitrous oxide (NO) to the atmosphere. Here we provide evidence that seasonally frozen peatlands are important NO emission sources in the Northern Hemisphere and the thawing periods are the hot moment of annual NO emissions.

Contribution of Ammonium-Induced Nitrifier Denitrification to NO in Paddy Fields.

Paddy fields are one of the most important sources of nitrous oxide (NO), but biogeochemical NO production mechanisms in the soil profile remain unclear. Our study used incubation, dual-isotope (N-O) labeling methods, and molecular techniques to elucidate NO production characteristics and mechanisms in the soil profile (0-60 cm) during summer fallow, rice cropping, and winter fallow periods. The results pointed out that biotic processes dominated NO production (72.

Complete ammonia oxidization in agricultural soils: High ammonia fertilizer loss but low N O production.

The contribution of agriculture to the sustainable development goals requires climate-smart and profitable farm innovations. Increasing the ammonia fertilizer applications to meet the global food demands results in high agricultural costs, environmental quality deterioration, and global warming, without a significant increase in crop yield. Here, we reported that a third microbial ammonia oxidation process, complete ammonia oxidation (comammox), is contributing to a significant ammonia fertilizer loss (41.

Nitrifiers Cooperate to Produce Nitrous Oxide in Plateau Wetland Sediments.

The thawing of dormant plateau permafrost emits nitrous oxide (NO) through wetlands; however, the NO production mechanism in plateau wetlands is still unclear. Here, we used the N-O double tracer technique and metagenomic sequencing to analyze the NO production mechanism in the Yunnan-Kweichow and Qinghai-Tibet plateau wetlands during the summer of 2020. NO production activity was detected in all 16 sediment samples (elevation 1020-4601 m: 2.

Towards a more labor-saving way in microbial ammonium oxidation: A review on complete ammonia oxidization (comammox).

In the Anthropocene, nitrogen pollution is becoming an increasing challenge for both mankind and the Earth system. Microbial nitrogen cycling begins with aerobic nitrification, which is also the key rate-limiting step. For over a century, it has been accepted that nitrification occurs sequentially involving ammonia oxidation, which produces nitrite followed by nitrite oxidation, generating nitrate.

Comammox activity dominates nitrification process in the sediments of plateau wetland.

The recent discovery of complete ammonia oxidation (comammox) has increased our understanding of nitrification. Although comammox has been shown to play an important role in plain wetland ecosystems, studies of comammox contribution are still limited in plateau wetland ecosystems. Here, we analyzed the abundance, activity, community and biogeochemical mechanisms of the comammox bacteria in Yunnan-kweichow and Qinghai-Tibet plateau wetlands from elevations of 1000-5000 m.

Heavy metal could drive co-selection of antibiotic resistance in terrestrial subsurface soils.

Terrestrial surface ecosystems are important sinks for antibiotic resistance genes (ARGs) due to the continuous discharge of contaminants from human-impacted ecosystems. However, the abundance and resistance types of ARGs and their influencing factors in terrestrial subsurface soils are not well known. In this study, we investigated the abundance and diversity of ARGs, and their correlations with metal resistance genes (MRGs), mobile genetic elements (MGEs), bacteria, and heavy metals in subsurface soils using high throughput quantitative PCR and metagenomic sequencing approaches.

Abundance and Functional Importance of Complete Ammonia Oxidizers and Other Nitrifiers in a Riparian Ecosystem.

The discovery of complete ammonia oxidation (comammox) has altered our understanding of nitrification, which is the rate-limiting process in the global nitrogen cycle. However, understanding the ecological role of comammox or its contribution to nitrification in both natural and artificial ecosystems is still in its infancy. Here, we investigated the community distribution and function of comammox bacteria in riparian ecosystems and analyzed interactions between comammox and other nitrogen cycling microorganisms.

Air pollution could drive global dissemination of antibiotic resistance genes.

Antibiotic-resistant pathogens pose a significant threat to human health. Several dispersal mechanisms have been described, but transport of both microbes and antibiotic resistance genes (ARGs) via atmospheric particles has received little attention as a pathway for global dissemination. These atmospheric particles can return to the Earth's surface via rain or snowfall, and thus promote long-distance spread of ARGs.

Applying constructed wetland-microbial electrochemical system to enhance NH removal at low temperature.

NH removal at low temperature (<10 °C) has baffled researchers and engineers for decades. Bioelectrochemical process has been increasingly valued as a promising approach to enhance NH removal by both electrochemical and stimulated microbial processes. The feasibility and the mechanism of enhanced NH removal were investigated in Constructed Wetland-Microbial Electrochemical System (CW-MES) with different electrode spacings including Constructed Wetland-Microbial Fuel Cell (CW-MFC) and Constructed Wetland-Microbial Electrolysis Cell (CW-MEC) at low temperature.

Dissimilatory nitrate reduction to ammonium (DNRA) in traditional municipal wastewater treatment plants in China: Widespread but low contribution.

Recent reports on the occurrence and contribution of dissimilatory nitrate reduction to ammonium (DNRA) in marine, inland water, and soil systems have greatly improved our understanding of the global nitrogen (N) cycle. This also promoted the investigation of the role and ecological features of DNRA in anthropogenic ecosystems. However, so far, the use of DNRA in municipal wastewater treatment plants (WWTPs), which are one of the most common and largest biotechnologically artificial water ecosystems, has not been investigated.

Comammox bacterial abundance, activity, and contribution in agricultural rhizosphere soils.

The newly identified complete ammonia oxidation (comammox), which is capable of oxidizing ammonia directly to nitrate, has complemented our knowledge of nitrification in the global nitrogen (N) cycle. However, understanding the contribution and ecological roles of comammox in complex soil environments is still in its infancy. Here, the community structure and function of comammox and the interactions with other ammonia oxidation processes in rhizosphere and non-rhizosphere soils of four different crop fields (maize, cotton, soybean, and millet) were investigated in summer and winter.

Application of the Cobas 4800 System for the Detection of High-Risk Human Papillomavirus in 5650 Asymptomatic Women.

High-risk papillomavirus (HR-HPV) testing combined with cytology improves the detection of cervical lesions and increases length of screening intervals. For a population-based HR-HPV survey, testing automation is in great need. The Cobas 4800 HPV Test System is a fully automated assay that can simultaneously detect HPV16, HPV18, and other 12 pooled HR-HPV genotypes.

Recovering partial nitritation in a PN/A system during mainstream wastewater treatment by reviving AOB activity after thoroughly inhibiting AOB and NOB with free nitrous acid.

Starting up or recovering partial nitritation is a major challenge for achieving or maintaining stable partial nitritation/anammox (PN/A) during mainstream wastewater treatment. This study presents a novel strategy for recovering the nitrite pathway by selectively reviving ammonium oxidizing bacteria (AOB) after thoroughly inhibiting AOB and nitrite oxidizing bacteria (NOB) using free nitrous acid (FNA). A sequencing batch reactor was operated for PN/A to treat real domestic wastewater for 423 days, during which twice FNA treatment was temporarily implemented.

Hotspot of dissimilatory nitrate reduction to ammonium (DNRA) process in freshwater sediments of riparian zones.

Dissimilatory nitrate reduction to ammonium (DNRA), an important intermediate process in the N-cycle, links N-compound oxidation and reduction processes. Hence, the oxic-anoxic interface would be the hotspot of the DNRA process. In freshwater ecosystems, the riparian zone is the most typical carrier of the oxic-anoxic interface.

Biogeographic distribution of comammox bacteria in diverse terrestrial habitats.

Comammox, the microbial group capable of completely oxidizing ammonia to nitrate, challenged the traditional two-step nitrification process where ammonia is oxidized by ammonia-oxidizing archaea (AOA) and bacteria (AOB), and nitrite by nitrite-oxidizing bacteria (NOB). However, the distribution of comammox bacteria in various habitats and their potential environmental drivers remain poorly understood. Using qPCR and high-throughput sequencing approach, we analyzed the abundance and community patterns of comammox from 38 samples taken from five different habitat types including paddy fields in Shaoguan and Antu, the wheat fields, river, and grassland in the Qinghai-Tibet Plateau, and the fringe and central riparian zones of Chaohu Lake of China during winter and summer.

Source, contribution and microbial N-cycle of N-compounds in China fresh snow.

The importance and contribution of nitrogen compounds and the related microbial nitrogen cycling processes in fresh snow are not well understood under the current research background. We collected fresh snow samples from 21 cities that 80% are from China during 2016 and 2017. Principal component analysis showed that SO were in the first principal component, and N-compounds were the second.

Global Distribution of Anaerobic Ammonia Oxidation (Anammox) Bacteria - Field Surveys in Wetland, Dryland, Groundwater Aquifer and Snow.

The discovery of anaerobic ammonia oxidation (anammox) expanded our knowledge on the microbial nitrogen cycle. Previous studies report that anammox bacteria are distributed in a wide range of habitats and plays significant roles in the global nitrogen cycle. However, most studies focus only on individual ecosystems or datasets from public databases.

Robustness of anammox granular sludge treating low-strength sewage under various shock loadings: Microbial mechanism and little NO emission.

With the increasing application of anammox for the treatment of high-strength industrial wastewater, application of anammox in municipal sewage has been gaining more attention. Sludge granulation in particular enhances the enrichment and retention of anammox bacteria in municipal sewage treatment systems. However, the performance of granular sludge under continuous and varying hydraulic loading shock remains little understood.