Interkingdom cross-talk using N-acyl homoserine lactones (AHLs)

Master Thesis subject (30 ECTS)
Diatoms and bacteria form the basis of complex patches of microorganisms which are known as biofilms. In bacteria as well as in diatoms group behavior is often regulated by the release of small molecules such as Quorum sensing molecules and hormones, respectively. Interestingly it has been shown in several examples that different signalling molecules cannot only be received by members of the same species but also across kingdoms, meaning diatoms can recognize bacterial signals and vice versa. Such interactions imply a previously unrecognised way by which both groups can influence each others growth, spatial distribution and ecological function within local communities. This thesis will focus on response of diatoms to N-acyl homoserine lactones (AHLs) - the most prominent group of QS molecules. Recently we established that several of these signaling molecules have a growth-suppressing or growth-promoting effect on marine biofilm diatoms and that these effects are partly conserved, partly specific among the species tested. To study the nature of these positive and negative effects we will make of a panel of genotyped strains which will permit to identify genomic regions associated with the response to AHLs and, based on their composition, to locate genes that can be expected to respond to such signals. Gene expression studies will then be used to validate the response of selected genes. The tasks in this project include a combination of laboratory assays, PAM fluorescence and automated imaging analysis, bio-informatics and molecular work.
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Reference Number: RP-48431