USE OF MOLECULAR APPROACHES TO STUDY THE OCCURRENCE OF EXTREMOPHILES AND EXTREMODURES IN NON-EXTREME ENVIRONMENTS

A number of samples were collected from various extreme and non-extreme environments. A range of molecular approaches, in addition to classical microbiology techniques, were used to isolate microorganisms, mainly archaea and bacteria from unusual environments. Halo-bacteria and archaea from non-saline environments and alkaliphilic bacteria and archaea capable of withstanding low pH values were isolated and identified using 16S rRNA gene cloning, PCR amplification and phylogenetic analysis. Detailed analysis of their halophilic and alkaliphilic physiology for adaptation in the environment was investigated using nuclear magnetic resonance spectroscopy (NMR) to detect the compatible solutes and atomic emission spectophotometery (AES) to measure the cellular potassium ions. In addition, ultraviolet-type C tolerant bacteria were isolated from terrestrial environments using phylogenetic analysis of the 16S rRNA gene sequences.
A selection of other molecular techniques were used in this thesis. Fluorescent in situ hybridisation (FISH) allowed simultaneous identification, enumeration and visualization of microbial cells of the two domains; Archaea and Bacteria within a community in their natural habitat. In addition, using EZ-PCR test, culturable-independent Mycoplasma DNA in environmental samples was detected.
Further investigation, using other advanced molecular techniques, into the physiology of extremophilic microorganisms found in non-extreme environment may provide a better understanding of the microbial interactions and the essential roles which different species play in the environment.