PhD title: Developing CRISPR genome engineering tools to understand nitrogen cycling by novel archaea
Nitrification is a key step in the global nitrogen biogeochemical cycle that facilitates the bioavailability of nitrogen. It is a two-step reaction involving the initial oxidation of ammonia to nitrite and the subsequent conversion of nitrites to nitrates. The release of nitrates and nitrous oxide, key players in eutrophication and greenhouse gas emissions respectively, highlight the role of nitrification in environmental change.
The oxidation of ammonia, the rate limiting step in nitrification, is performed by two distinct groups of organisms; ammonia oxidizing bacteria (AOB) and the ammonia oxidizing archaea (AOA). AOA have only recently been discovered and consequently there is limited information available on their ecology, physiology hindering comprehensive comparative studies with AOB. Studies to-date have identified evidence for niche differentiation between these two distinct groups of microorganisms. For example, AOA frequently favour low pH and low ammonia environments although the underlying mechanisms to this adaptation is yet unclear. Therefore, to ensure effective use of agricultural land and mitigate nitrogen losses, it is critical to understand the basis for niche selection in AOA.
This project aims to isolate and characterise a novel AOA strain, characterise the ammonia uptake pathway (absent in AOB) and make a correlation between archaeal cell physiology and their ecological niche.
The project will make use of a powerful CRISPR-Cas9 genetic engineering approach to knockout genes associated with ammonia uptake in archaeal strains.
Regulation of HIV receptor expression in cervical epithelial cells by Gram-negative bacterial lipopolysaccharide
Draft Genome Sequences of Three Bacillus Species from South African Marine Sponges
Co-awarded a travel grant by the National Research Foundation (South Africa)
Practical Demonstrator – Life sciences undergraduate training laboratories (University of the Western Cape).