Biohydrogen utilization in legume-rhizobium symbiosis reveals a novel mechanism of accelerated tetrachlorobiphenyl transformation.

Symbiosis between Glycine max and Bradyrhizobium diazoefficiens were used as a model system to investigate whether biohydrogen utilization promotes the transformation of the tetrachlorobiphenyl PCB77. Both a H uptake-positive (Hup) strain (wild type) and a Hup strain (a hupL deletion mutant) were inoculated into soybean nodules. Compared with Hup nodules, Hup nodules increased dechlorination significantly by 61.

Nitrogen transfer and cross-feeding between Azotobacter chroococcum and Paracoccus aminovorans promotes pyrene degradation.

Nitrogen is a limiting nutrient for degraders function in hydrocarbon-contaminated environments. Biological nitrogen fixation by diazotrophs is a natural solution for supplying bioavailable nitrogen. Here, we determined whether the diazotroph Azotobacter chroococcum HN can provide nitrogen to the polycyclic aromatic hydrocarbon-degrading bacterium Paracoccus aminovorans HPD-2 and further explored the synergistic interactions that facilitate pyrene degradation in nitrogen-deprived environments.

Endogenous biohydrogen from a rhizobium-legume association drives microbial biodegradation of polychlorinated biphenyl in contaminated soil.

Endogenous hydrogen (H) is produced through rhizobium-legume associations in terrestrial ecosystems worldwide through dinitrogen fixation. In turn, this gas may alter rhizosphere microbial community structure and modulate biogeochemical cycles. However, very little is understood about the role that this H leaking to the rhizosphere plays in shaping the persistent organic pollutants degrading microbes in contaminated soils.

Enhancement of nitrogen fixation and diazotrophs by long-term polychlorinated biphenyl contamination in paddy soil.

Biological nitrogen fixation (BNF) driven by diazotrophs is a major means of increasing available nitrogen (N) in paddy soil, in addition to anthropogenic fertilization. However, the influence of long-term polychlorinated biphenyl (PCB) contamination on the diazotrophic community and nitrogen fixation in paddy soil is poorly understood. In this study, samples were collected from paddy soil subjected to > 30 years of PCB contamination, and the soil diazotrophic community and N fixation rate were evaluated by Illumina MiSeq sequencing and acetylene reduction assays, respectively.

Effects of combined pollution of organic pollutants and heavy metals on biodiversity and soil multifunctionality in e-waste contaminated soil.

Electronic waste (e-waste) is increasing globally, but the impact of this source of combined pollution on soil biodiversity and multiple soil functions (i.e., ecosystem multifunctionality) remains unclear.

Variations of Bacterial and Diazotrophic Community Assemblies throughout the Soil Profile in Distinct Paddy Soil Types and Their Contributions to Soil Functionality.

Soil microbiota plays fundamental roles in maintaining ecosystem functions and services, including biogeochemical processes and plant productivity. Despite the ubiquity of soil microorganisms from the topsoil to deeper layers, their vertical distribution and contribution to element cycling in subsoils remain poorly understood. Here, nine soil profiles (0 to 135 cm) were collected at the local scale (within 300 km) from two canonical paddy soil types (Fe-accumuli and Hapli stagnic anthrosols), representing redoximorphic and oxidative soil types, respectively.

Microbial diversity drives pyrene dissipation in soil.

Soil microbial diversity is an essential driver of multiple ecosystem functions and services. However, the role and mechanisms of microbial diversity in the dissipation of persistent organic pollutants in soil are largely unexplored. Here, a gradient of soil microbial diversity was constructed artificially by a dilution-to-extinction approach to assess the role of soil microbial diversity in the dissipation of pyrene, a high molecular weight polycyclic aromatic hydrocarbon (PAH), in a 42-day microcosm experiment.

Soil bacterial diversity and functionality are driven by plant species for enhancing polycyclic aromatic hydrocarbons dissipation in soils.

Plant-microorganisms symbiosis has been widely used in developing strategies for the rhizoremediation of polycyclic aromatic hydrocarbon (PAHs) contaminated agricultural soils. However, understanding the potential mechanisms for using complex plant-microbe interactions to enhance rhizoremediation in contaminated soils is still limited. In this study, rhizosphere microbiomes were established by cultivating four types of cover crops for 15 months in a PAHs-contaminated field.

Enhanced biomass and cadmium accumulation by three cadmium-tolerant plant species following cold plasma seed treatment.

Cold plasma seed treatment can promote plant growth and enhance the resistance of agricultural crops to adverse stress. However, the effects of plasma seed treatment on the growth and phytoextraction response of plants to cadmium (Cd) remain poorly documented. Here, we have investigated the feasibility of using plasma seed treatment to enhance the biomass and Cd accumulation of three Cd-tolerant species, namely Bidens pilosa L, Solanum nigrum L.

The inhibitory mechanism of natural soil colloids on the biodegradation of polychlorinated biphenyls by a degrading bacterium.

In spite of extensive studies of soil model components, the role of natural soil colloids in the biodegradation of organic pollutants remain poorly understood. Accordingly, the present study selected Mollisol colloids (MCs) and Ultisol colloids (UCs) to investigate their effects on the biodegradation of 3, 3', 4, 4'-tetrachlorobiphenyl (PCB77) by Bradyrhizobium diazoefficiens USDA 110. Results demonstrated that both natural soil colloids significantly decreased the biodegradation of PCB77, which partly resulted from the significant decrease in the bioaccessibility of PCB77.

Soil Type Driven Change in Microbial Community Affects Poly(butylene adipate--terephthalate) Degradation Potential.

Biodegradable mulch films have been developed as a suitable alternative to conventional nondegradable polyethylene films. However, the key factors controlling the degradation speed of biodegradable mulch films in soils remain unclear. Here, we linked changes in the soil microbiome with the degradation rate of a promising biodegradable material poly(butylene adipate--terephthalate) (PBAT) in four soil types, a lou soil (LS), a fluvo-aquic soil (CS), a black soil (BS), and a red soil (RS), equivalent to Inceptisols (the first two soils), Mollisols, and Ultisols, using soil microcosms.

Changes in clover rhizosphere microbial community and diazotrophs in mercury-contaminated soils.

Little is known about the response of the soil microbiome (including bacteria in the rhizosphere of legumes such as clover) to mercury (Hg) despite the toxicity of Hg to soil microorganisms. Here, Hg-contaminated soils collected from Guizhou province, southwest China, were divided into three groups according to their Hg contents and were planted with clover. High-throughput sequencing of bacterial 16S rRNA and nitrogenase (nifH) genes and quantitative polymerase chain reaction (qPCR) were used to study the response of bacteria and diazotrophs to soil Hg stress and the effects of Hg on the abundance of functional genes in rhizosphere soils.

miR-30a-3p participates in the development of asthma by targeting CCR3.

This study aimed to investigate the role and relevant mechanism of miR-30a-3p action in asthma. The results of this study revealed that the expression levels of miR-30a-3p were significantly decreased in the peripheral blood of asthmatic patients. In addition, we found that the CC chemokine receptor (CCR3) was a target of miR-30a-3p.

Low Concentrations of Silver Nanoparticles and Silver Ions Perturb the Antioxidant Defense System and Nitrogen Metabolism in N-Fixing Cyanobacteria.

Although toxic effects of silver nanoparticles (AgNPs) on aquatic organisms have been extensively reported, responses of nitrogen-fixing cyanobacteria to AgNPs/Ag under environmentally relevant concentrations are largely unknown. Here, cyanobacteria were exposed to different concentrations of AgNPs (0.01, 0.

Exploring bacterial community structure and function associated with polychlorinated biphenyl biodegradation in two hydrogen-amended soils.

Hydrogen (H) is a universal energy source supplying survival energy for numerous microbial functions. Diffusive fluxes of H released by rhizobacterial symbiont nodules in which H is an obligate by-product of dinitrogen fixation may act as an additional energy input shaping microbial community structure and function in soils. However, the effects of H at the soil-nodule interface on soil contaminant degradation processes are poorly understood.

Pesticide residues in soils planted with Panax notoginseng in south China, and their relationships in Panax notoginseng and soil.

In this study, 73 samples from soils planted with Panax notoginseng and six P. notoginseng samples were collected in Yunnan Province to investigate the residual levels of six pesticides and their relationships with P. notoginseng and soil.

Contribution of autochthonous diazotrophs to polycyclic aromatic hydrocarbon dissipation in contaminated soils.

Understanding the role played by autochthonous functional microbes involved in the biotransformation of pollutants would help optimize bioremediation performance at contaminated sites. However, our knowledge of the remediation potential of indigenous diazotrophs in contaminated soils remains inadequate. Using a microcosm experiment, soil nitrogen fixation activity was manipulated by molybdenum (Mo) and tungsten (W), and their effect on the removal of polycyclic aromatic hydrocarbons (PAHs) was determined in agricultural and industrial soils.

Function of Biohydrogen Metabolism and Related Microbial Communities in Environmental Bioremediation.

Hydrogen (H) metabolism has attracted considerable interest because the activities of H-producing and consuming microbes shape the global H cycle and may have vital relationships with the global cycling of other elements. There are many pathways of microbial H emission and consumption which may affect the structure and function of microbial communities. A wide range of microbial groups employ H as an electron donor to catalyze the reduction of pollutants such as organohalides, azo compounds, and trace metals.

Effect of composition and microstructure of humic acid on 3,3',4,4'-tetrachlorobiphenyl sorption.

The fate and transport of polychlorinated biphenyls (PCBs), a class of persistent organic compounds, in soils was markedly affected by their sorption/desorption on soil organic matters (SOM) due to high hydrophobicity of PCBs. Humic acid (HA), an important fraction of SOM, has no steady composition and microstructure from different origins, resulting in their diverse sorption capacity. Therefore, the effect of composition and microstructure of HA on sorption of 3,3',4,4'-tetrachlorobiphenyl (PCB77) was investigated in this study.

Coupling between Nitrogen Fixation and Tetrachlorobiphenyl Dechlorination in a Rhizobium-Legume Symbiosis.

Legume-rhizobium symbioses have the potential to remediate soils contaminated with chlorinated organic compounds. Here, the model symbiosis between Medicago sativa and Sinorhizobium meliloti was used to explore the relationships between symbiotic nitrogen fixation and transformation of tetrachlorobiphenyl PCB 77 within this association. 45-day-old seedlings in vermiculite were pretreated with 5 mg L PCB 77 for 5 days.

Retrospective analysis of non-laboratory-based adverse drug reactions induced by intravenous radiocontrast agents in a Joint Commission International-accredited academic medical center hospital in China.

The authors retrospectively analyzed the pattern and characteristics of non-laboratory-based adverse drug reactions (ADRs) induced by intravenous radiocontrast agents in a large-scale hospital in China during 2014-2015. There were 314 ADR cases among 118,208 patients receiving enhanced CT or MRI examinations. The frequency of moderate/severe ADRs defined by Chinese Society of Radiology (ie, severe vomiting, systematic urticaria, facial swelling, dyspnea, vasovagal reaction, laryngeal edema, seizure, trembling, convulsions, unconsciousness, shock, death, and other unexpected adverse reactions) was rare (0.

Rhizobial symbiosis alleviates polychlorinated biphenyls-induced systematic oxidative stress via brassinosteroids signaling in alfalfa.

The role of symbiotic rhizobia in the alleviation of polychlorinated biphenyl (PCB)-induced phytotoxicity in alfalfa and the brassinosteroid (BR) hormone signaling involved were investigated during phytoremediation. The association between alfalfa and Sinorhizobium meliloti was adopted as a remediation model. Phytotoxicity due to PCB 77 (3,3',4,4'-tetrachlorobiphenyl) exerted adverse impacts on plant performance (biomass accumulation and photosynthesis) and elicited cellular oxidative stress (overproduction of reactive oxygen species, lipid peroxidation, and cell necrosis) which was largely attenuated by pre-inoculation with S.

Biodegradation of pentachloronitrobenzene by Cupriavidus sp. YNS-85 and its potential for remediation of contaminated soils.

Pentachloronitrobenzene (PCNB) is a toxic chlorinated nitroaromatic compound. However, only a few bacteria have been reported to be able to utilize PCNB. In the present study, one pentachloronitrobenzene (PCNB)-degrading bacterium, Cupriavidus sp.

Biodegradation of 3,3',4,4'-tetrachlorobiphenyl by Sinorhizobium meliloti NM.

A rhizobial strain, Sinorhizobium meliloti NM, could use 3,3',4,4'-tetrachloro-biphenyl (PCB 77) as the sole carbon and energy source for growth in mineral salt medium. The degradation efficiency of PCB 77 by strain NM and the bacterial growth increased with a decrease in PCB 77 concentration (5-0.25mgL(-1)).

Fungal endophyte Phomopsis liquidambari affects nitrogen transformation processes and related microorganisms in the rice rhizosphere.

The endophytic fungus Phomopsis liquidambari performs an important ecosystem service by assisting its host with acquiring soil nitrogen (N), but little is known regarding how this fungus influences soil N nutrient properties and microbial communities. In this study, we investigated the impact of P. liquidambari on N dynamics, the abundance and composition of N cycling genes in rhizosphere soil treated with three levels of N (urea).