A Study of Symbiotic Microbial Communities: Alternative Nitrogenase Gene Diversity in Termite Guts

Abstract

Although most of the Earth’s atmosphere contains nitrogen gas, most organisms arenot able to use this form of nitrogen. Certain microbes called diazotrophs are able toconvert atmospheric nitrogen gas into a more usable form such as ammonia througha process called nitrogen fixation. The enzyme that catalyzes nitrogen fixation iscalled nitrogenase and can exist in three different forms depending on whether theycontain the trace metals Mo, V, or Fe-only at the active site of the dinitrogenasesubunit. The canonical Mo nitrogenase has been most extensively studied because itwas discovered first. In this project, I wish to add to our limited knowledge of thealternative (V and Fe-only) nitrogenases by searching for their presence in certainenvironments. Using Bellenger et al. nifD/anfD/vnfD primers, I searched for theirpresence in the wood-feeding termite Zootermopsis angusticollis because I havereason to believe they are selected over the canonical Mo nitrogenase due to theirhigher H2 production capacity and consequently ability to contribute to the internaltermite gut H2 flow mechanism.