Nile tilapia (Oreochromis niloticus) show high tolerance to acute ammonia exposure but lose metabolic scope during prolonged exposure at low concentration.

Ammonia is a respiratory gas that is produced during the process of protein deamination. In the unionised form (NH), it readily crosses biological membranes and is highly toxic to fish. In the present study we examined the effects of unionized ammonia (UIA), on the resting oxygen consumption (MO), ventilation frequency (f), heart rate (HR) and heart rate variability (HRV) in Nile tilapia (Oreochromis niloticus).

Effects of transgenic glufosinate-tolerant oilseed rape (Brassica napus) and the associated herbicide application on eubacterial and Pseudomonas communities in the rhizosphere.

A containment experiment was carried out in order to evaluate possible shifts in eubacterial and Pseudomonas rhizosphere community structures due to the release of genetically modified Basta-tolerant oilseed rape and the associated herbicide application. Treatments included cultivation of the transgenic plant as well as of the wild-type cultivar in combination with mechanical removal of weeds and the application of the herbicides Basta (active ingredient: glufosinate) and Butisan S (active ingredient: metazachlor). Rhizosphere soil was sampled from early and late flowering plants as well as from senescent plants.

RNA isolation from soil for bacterial community and functional analysis: evaluation of different extraction and soil conservation protocols.

The impact of three different RNA isolation methods on the community analysis of metabolically active bacteria was determined by reverse transcription (RT) and PCR amplification of 16S rRNA genes and subsequent terminal restriction fragment length polymorphism (T-RFLP) analysis. Furthermore, soil samples were stored at different conditions in order to evaluate the effect of soil conservation methods on the outcome of the population analysis. The quality of mRNA was assessed by reverse transcription and PCR amplification of eubacterial glutamine synthetase genes.