The potential effects of engineered metal oxide nanoparticles (MONPs) on bacterial nitrogen fixation are of great concern. Herein, the impact and mechanism of the increasing-used MONPs, including TiO, AlO, and ZnO nanoparticles (TiONP, AlONP, and ZnONP, respectively), on nitrogenase activity was studied at the concentrations ranging from 0 to 10 mg L using associative rhizosphere nitrogen-fixing bacteria Pseudomonas stutzeri A1501. Nitrogen fixation capacity was inhibited by MONPs in an increasing degree of TiONP < AlONP < ZnONP. Realtime qPCR analysis showed that the expressions of nitrogenase synthesis-related genes, including nifA and nifH, were inhibited significantly when MONPs were added. MONPs could cause the explosion of intracellular ROS, and ROS not only changed the permeability of the membrane but also inhibited the expression of nifA and biofilm formation on the root surface. The repressed nifA gene could inhibit transcriptional activation of nif-specific genes, and ROS reduced the biofilm formation on the root surface which had a negative effect on resisting environmental stress. This study demonstrated that MONPs, including TiONP, AlONP, and ZnONP, inhibited bacterial biofilm formation and nitrogen fixation in the rice rhizosphere, which might have a negative effect on the nitrogen cycle in bacteria-rice system.
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http://dx.doi.org/10.1016/j.chemosphere.2023.139223 | DOI Listing |
World J Microbiol Biotechnol
January 2025
Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, School of Geographical Sciences, Fujian Normal University, Fuzhou, China.
Nitrification, the oxidation of ammonium to nitrate via nitrite, links nitrogen fixation and nitrogen loss processes, playing key roles in coastal nitrogen cycle. However, few studies have simultaneously examined both ammonia-oxidizing and nitrite-oxidizing microbes. This work investigated the abundance and community structure of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and nitrite-oxidizing bacteria (NOB) using archaeal amoA gene, bacterial amoA gene, and NOB nxrB gene, respectively, through q-PCR and Sanger sequencing along the Changjiang Estuary salinity gradient.
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January 2025
Inner Mongolia Key Laboratory of Soil Quality and Nutrient Resources, Key Laboratory of Agricultural Ecological Security and Green Development at Universities of Inner Mongolia Autonomous Region, Inner Mongolia Agricultural University, Hohhot, China.
Background: The application of nitrogen (N) fertilizer to alfalfa ( L.) has received little attention due to the ability of this plant to fix N. However, N deficiency stress is often observed in marginal lands of China, especially in saline-alkali soils.
View Article and Find Full Text PDFSoil salinization poses a significant ecological and environmental challenge both in China and across the globe. Plant growth-promoting rhizobacteria (PGPR) enhance plants' resilience against biotic and abiotic stresses, thereby playing a vital role in soil improvement and vegetation restoration efforts. PGPR assist plants in thriving under salt stress by modifying plant physiology, enhancing nutrient absorption, and synthesizing plant hormones.
View Article and Find Full Text PDFEnviron Res
January 2025
College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, Guangxi, China; Provincial and Ministerial Collaborative Innovation Center for Sugar Industry, Nanning 530004, Guangxi, China; Engineering Research Center for Sugar Industry and Comprehensive Utilization, Ministry of Education, Nanning 530004, Guangxi, China. Electronic address:
To enhance the retention of compost nutrients, specifically in nitrogen metabolism and humification, compound microbial agents were added during the aerobic composting of bagasse pith and buffalo manure. The introduction of the microbial agent successfully colonized the mixture, boosted the degradation capacity of organic matter, and facilitated the formation of nitrogenous substances and humic substances (HSs). The incorporation of a composite microbial inoculum led to a substantial rise in total Kjeldahl nitrogen (TKN) by 62.
View Article and Find Full Text PDFChemosphere
January 2025
U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, USA. Electronic address:
Cyanobacteria harmful algal blooms in lakes are primarily driven by nutrient and temperature conditions, yet the interplay of these abiotic factors with microbial community dynamics during bloom events is complex and challenging to unravel. Despite advances through deep sequencing approaches, the underlying transcriptomic changes occurring within blooming and non-blooming taxa remains an actively expanding area of study. In this work, we examined a spring-summer bloom event in Anderson Lake, WA, which has experienced recurring annual blooms dominated by the filamentous, anatoxin-a producing, diazotroph: Dolichospermum sp.
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