The Role of FNR-Regulated sRNA in Controlling Bacterial Denitrification

Seagrove, Daniel James (2024) The Role of FNR-Regulated sRNA in Controlling Bacterial Denitrification. Masters thesis, University of East Anglia.

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Nitrous Oxide (N2O) is a long-lived, ozone-depleting greenhouse gas of which emissions are increasing at an alarming rate, largely due to modern agricultural practices. Biological N2O primarily originates from a truncated denitrification pathway which normally allows the sequential reduction of nitrate (NO3) to nitrogen (N2) under anaerobic conditions by four reductases: nitrate reductase, nitrite reductase, nitric oxide reductase and nitrous oxide reductase. The denitrification pathway is tightly regulated by transcriptional regulators belonging to the FNR family. A number of environmental signals have significant impact on these transcriptional regulators and the activity of denitrification. A relatively new area of study has looked at regulation of denitrification by small RNAs (sRNAs), which have previously been found to have a wide range of physiological functions and are largely controlled themselves by transcriptional regulators. Previous studies have identified the sRNAs in the model bacterial denitrifier Paracoccus denitrificans. Here it was hypothesised that as FNR transcriptional regulators play a key role regulating the denitrification pathway that sRNAs under the control of FNR transcriptional regulators may also play a key role in regulating denitrification. This study aimed to identify sRNAs with a putative FNR binding motif upstream of their promoter region. 7 sRNAs with a putative FNR binding motif within 200 bp of their promoter regions were discovered on the P. denitrificans genome and these sRNAs were subsequently computationally characterised. Their secondary structures, mRNA targets and sequence conservation in other species of bacteria were investigated. 3 of these candidate sRNAs, sRNA18, sRNA36 and sRNA79 showed the most likely characteristics to be involved in denitrification. Overexpression of sRNA36 impacted on the rate of N2O reduction and regulation by FNR was experimentally confirmed.

Item Type: Thesis (Masters)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Chris White
Date Deposited: 27 Jun 2024 05:41
Last Modified: 27 Jun 2024 05:41


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