Quantitative analysis of nifH genes and transcripts from aquatic environments

Area of Science:

• Microbiology
• Environmental Science
• Molecular Biology

Background:

• Nitrogen availability is critical for primary production in ecosystems.
• Biological nitrogen fixation is a key source of nitrogen in marine environments.
• Understanding nitrogen-fixing microorganisms is vital for global nitrogen and carbon cycle research.

Purpose of the Study:

• To investigate the ecology and gene expression of nitrogen-fixing bacteria in aquatic environments.
• To apply quantitative molecular tools for direct environmental examination of uncultivated microbes.
• To describe quantitative PCR (Q-PCR) and Q-RT-PCR protocols for nifH gene analysis.

Main Methods:

• Utilized quantitative polymerase chain reaction (Q-PCR) and quantitative reverse transcriptase PCR (Q-RT-PCR).
• Employed 5' nuclease assay protocols for analyzing nifH gene fragments.
• Examined environmental samples from aquatic ecosystems.

Main Results:

• Discovered distinct, nonrandom distributions of specific estuarine diazotrophs.
• Observed different diel patterns of nifH gene expression in open ocean diazotrophs.
• Demonstrated the utility of Q-PCR and Q-RT-PCR for microbial ecology studies.

Conclusions:

• Quantitative molecular methods provide powerful insights into microbial ecology and gene expression.
• Estuarine and marine diazotrophs exhibit unique ecological and temporal distribution patterns.
• Methodological considerations are crucial for accurate quantitative microbial analysis in environments.