Related Experiment Video
Updated: Jul 16, 2026
10:03
Isolation, Propagation, and Identification of Bacterial Species with Hydrocarbon Metabolizing Properties from Aquatic Habitats
Published on: December 7, 2021
Functional Gene Hybridization Patterns of Terrestrial Ammonia-Oxidizing Bacteria
1Center for Microbial Ecology and Department of Crop and Soil Sciences, Michigan State University, East Lansing, MI 48824, USA
Microbial Ecology
|December 16, 1998
Summary
This study reveals significant genetic divergence in ammonia oxidation pathways between Nitrosomonas and Nitrosospira bacteria. Hydroxylamine oxidoreductase (hao) gene sequences show promise for analyzing terrestrial ammonia-oxidizing bacteria (AAOs).
Area of Science:
- Microbiology
- Environmental Science
- Biochemistry
Background:
- Autotrophic ammonia oxidation is crucial for nitrogen cycling.
- Research has primarily focused on Nitrosomonas europaea, neglecting other terrestrial groups.
- Terrestrial ammonia-oxidizing bacteria (AAOs) include Nitrosomonas and Nitrosospira.
Purpose of the Study:
- To investigate functional gene homologies in terrestrial AAOs.
- To assess the potential of N. europaea gene probes for analyzing Nitrosospira.
- To explore denitrification gene presence in AAOs.
Main Methods:
- Southern blot hybridization using 32P-labeled probes from N. europaea.
- Probes targeted genes: ammonia monooxygenase (amoA, amoB), hydroxylamine oxidoreductase (hao), and cytochrome c-554 (hcy).
- Hybridization performed under low and high stringency conditions with four Nitrosospira representatives.
Main Results:
- Significant divergence in ammonia oxidation genes (amoA, amoB, hao, hcy) between Nitrosomonas and Nitrosospira.
- The hao probe showed consistent hybridization, indicating its utility for terrestrial AAO analysis.
- Some Nitrosospira strains hybridized with a Cu-type nitrite reductase probe, suggesting varied denitrification capabilities.
Conclusions:
- Functional genes in the ammonia oxidation pathway have diverged between Nitrosomonas and Nitrosospira groups.
- The hao gene is a promising target for non-PCR-based molecular analysis of terrestrial AAOs.
- AAOs exhibit diversity in denitrification mechanisms and capacities.
Related Concept Videos
01:15Metabolism of Chemolithotrophs
Chemolithotrophs are microorganisms that obtain energy by oxidizing inorganic molecules such as hydrogen gas (H₂), ammonia (NH₃), reduced sulfur compounds (H₂S, S²⁻), and ferrous iron (Fe²⁺). Unlike heterotrophic organisms that rely on organic carbon, chemolithotrophs transfer electrons from these inorganic donors to the electron transport chain (ETC), generating a proton motive force (PMF) that drives ATP synthesis through oxidative phosphorylation. However, because inorganic electron donors...
01:22Inorganic Nitrogen Assimilation
Nitrogen is an essential element in biological systems, forming a crucial component of proteins, nucleic acids, and other cellular constituents. Many bacteria and archaea acquire nitrogen in the form of nitrate (NO₃⁻) or ammonia (NH₃), which are then assimilated into biomolecules through specific enzymatic pathways.Assimilatory Nitrate ReductionWhen nitrate enters the cell, it undergoes a two-step reduction process known as assimilatory nitrate reduction. Initially, the enzyme nitrate reductase...
01:28Anoxygenic Phototrophic Bacteria
Anoxygenic phototrophic bacteria are a diverse group of microorganisms that perform photosynthesis without producing oxygen. They primarily include purple sulfur bacteria, purple nonsulfur bacteria, green sulfur bacteria, and green nonsulfur bacteria. These bacteria are classified into the Gammaproteobacteria, Alphaproteobacteria, Betaproteobacteria, Chlorobi, and Chloroflexi lineages, each with distinct physiological and ecological adaptations.Purple sulfur bacteria belong to the...
01:21Hyperthermophilic Bacteria
Domain Bacteria includes some unique hyperthermophilic species. They exhibit remarkable adaptations that enable survival in extreme environments.Thermotoga species are rod-shaped, gram-negative, non-sporulating hyperthermophiles that form a sheath-like envelope called a toga. They ferment sugars or starch, producing lactate, acetate, CO₂, and H₂, and can also grow via anaerobic respiration using H₂ and ferric iron. Found in hot springs and hydrothermal vents, over 20% of their genes show strong...
01:30Diversity of Archaea I
Archaea, a domain of single-celled microorganisms, are classified into five major phyla based on genetic and biochemical characteristics: Euryarchaeota, Crenarchaeota, Thaumarchaeota, Korarchaeota, and Nanoarchaeota. Among these, the phylum Euryarchaeota is notable for its remarkable diversity in morphology, metabolism, and ecological adaptations.Morphological and Metabolic DiversityMembers of Euryarchaeota exhibit a variety of cellular shapes, including rods and cocci. Their metabolic pathways...
01:26Microbes and the Nitrogen Cycle
The nitrogen cycle is a complex biogeochemical process critical to maintaining the balance of nitrogenous compounds in ecosystems. This cycle involves multiple microbial-mediated transformations through which nitrogen changes oxidation states, supporting essential ecological functions and contributing to plant and microbial growth.Nitrogen Fixation and AmmonificationNitrogen fixation initiates the cycle by converting inert atmospheric nitrogen (N₂) into bioavailable ammonia (NH₃), a process...