This study reports the molecular characterization of the nitrate-assimilation gene cluster from the opportunistic fungal pathogen Aspergillus fumigatus. A genomic fragment was isolated which contained the entire structural gene encoding nitrite reductase (niiA), plus segments of the nitrate reductase (niaD) and the nitrate transporter (crnA) genes. Nitrate-assimilation genes in A. fumigatus are physically linked and transcribed in the same direction as in A. nidulans. The nitrate-assimilation gene cluster is on the largest chromosome (5.3 Mb). The nitrite reductase (niiA) gene encodes a protein of 1110 amino acids that contains regions corresponding to FAD, NADPH, FeS and siroheme binding sites. Eight small introns interrupt the niiA open reading frame. The niaD-niiA intergenic regulatory region contains promoter consensus sequences including TATA, CAAT, and binding sites for the areA and nirA gene products. Northern analysis indicated that the expression of niaD, niiA and crnA are induced by nitrate and repressed by ammonium at the transcriptional level.
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http://dx.doi.org/10.1007/s002940050328 | DOI Listing |
Curr Microbiol
January 2025
Instituto de Ciencias Aplicadas, Facultad de Ingeniería, Universidad Autónoma de Chile, Sede Talca, Talca, 3460000, Chile.
In the present study, the taxonomic position of Salinisphaera halophila (NZ_AYKF00000000) and Salinisphaera orenii (NZ_AYKH00000000) was re-evaluated. In addition, their metabolic potentials and mechanisms for mitigating stress conditions were determined. Comparisons of 16S rRNA gene sequences, analysis of the phylogenetic tree, phylogenomic tree, average nucleotide identity (ANI), and digital DNA-DNA hybridization (dDDH) values were conducted.
View Article and Find Full Text PDFBioresour Technol
December 2024
CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai Shandong 264003, PR China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, PR China; Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266237, PR China. Electronic address:
Aerobic methanotrophs play a crucial role in controlling methane emission in wastewater treatment. However, the high nitrite produced during ammonium oxidation, nitrate assimilation, and denitrification hinders methane oxidation and nitrogen removal. In this study, Methylomonas sp.
View Article and Find Full Text PDFBMC Plant Biol
November 2024
PMI R&D, Philip Morris Products S.A., Quai-Jeanrenaud 5, Neuchâtel, 2000, Switzerland.
Background: We have previously shown that the expression of a constitutively active nitrate reductase variant and the suppression of CLCNt2 gene function (belonging to the chloride channel (CLC) gene family) in field-grown tobacco reduces tobacco-specific nitrosamines (TSNA) accumulation in cured leaves and cigarette smoke. In both cases, TSNA reductions resulted from a strong diminution of free nitrate in the leaf, as nitrate is a precursor of the TSNA-producing nitrosating agents formed during tobacco curing and smoking. These nitrosating agents modify tobacco alkaloids to produce TSNAs, the most problematic of which are NNN (N-nitrosonornicotine) and NNK (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone).
View Article and Find Full Text PDFNew Phytol
January 2025
Centre for Research in Agricultural Genomics (CRAG), Barcelona, 08193, Spain.
Transcription factors of the CYCLING DOF FACTOR (CDF) family activate in potato the SP6A FT tuberization signal in leaves. In modern cultivars, truncated StCDF1.2 alleles override strict SD control by stabilizing the StCDF1 protein, which leads to StCOL1 suppression and impaired activation of the antagonic SP5G paralog.
View Article and Find Full Text PDFInt J Biol Macromol
November 2024
Key Laboratory of Plant Nutrition and Agri-environment in Northwest China, Ministry of Agriculture, College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China. Electronic address:
NAR2 (Nitrate assimilation related protein) is a protein chaperone involved in transporting nitrate across membranes. However, the expression pattern and function of NAR2 genes in wheat are still largely unknown. Here, we cloned two TaNAR2 genes (TaNAR2.
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