title: Nitrification and occurrence of salt-tolerant nitrifying bacteria in the Negev desert soils.
abstract: Ammonia oxidation potential, major ammonia oxidizers and occurrence of salt-tolerant nitrifying bacteria were studied in soil samples collected from diverse ecosystems along the northern Negev desert. Great diversity in ammonia oxidation potential was observed among the soil samples, and ammonia oxidizers were the rate-limiting step of nitrification. Denaturing gradient gel electrophoresis and partial 16S rRNA gene sequences indicate that members of the genus Nitrosospira are the major ammonia oxidizers in the natural desert soil samples. Upon enrichment with different salt concentrations, salt-tolerant nitrifying enrichments were established from several soil samples. In two enrichments, nitrification was not inhibited by 400 mM NaCl. Electrophoretic analysis and partial 16S rRNA gene sequences indicate that Nitrosomonas species were dominant in the 400 mM salt enrichment. The results point towards the potential of the desert ecosystem as a source of stress-tolerant nitrifying bacteria or other microorganisms with important properties.
authors.affiliation: Department of Environmental Hydrology and Microbiology, Institute for Water Sciences and Technologies, The Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, 84990 Midreshet Ben-Gurion, Israel. alineji@bgumail.bgu.ac.il
authors.forename: Ali
authors.initials: A
authors.lastname: Nejidat
mesh_terms: D000641:Ammonia / Q000032:analysis* / Q000378:metabolism; D001483:Base Sequence; D016000:Cluster Analysis; D017931:DNA Primers; D003889:Desert Climate; D004586:Electrophoresis; D007557:Israel; D008969:Molecular Sequence Data; D043369:Nitrosomonadaceae / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000494:pharmacology; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology
chemical_list: D017931:DNA Primers; D012336:RNA, Ribosomal, 16S; D012987:Soil; D012965:Sodium Chloride; D000641:Ammonia