Joint work between Prof Shin-Ichi Aizawa and Prof Liz Sockett’s labs has revealed one of the secrets of the way that tiny predatory Bdellovibrio bacteria grow inside other bacteria. The paper published in the Journal of Bacteriology in December 2010 describes how PhD student Andy Fenton worked with HFSP funded scientists Dr Machi Kanna and Dr Richard Woods to study how the Bdellovibrio grow and divide, using the sole resources of the prey bacteria, E.coli, which they have invaded. The research was carried out as part of the HFSP Program Grant “Proteomics, genetics and ultrastructure of predator-prey interactions by Bdellovibrio bacteria”.
On this project Dr Machi Kanna painstakingly studied and counted the yields of Bdellovibrio produced when they invaded and consumed a single E.coli bacterium. She found that odd numbers as well as even numbers of progeny Bdellovibrio were produced, suggesting that the Bdellovibrio might not be dividing by the classical method of bacterial binary fission. Dr Richard Woods, who visited the University of Hiroshima where Dr Kanna and Prof Aizawa carried out the work, and collaborated with them, then constructed some fluorescently tagged prey bacterial cells. In these the Bdellovibrio were “backlit” by the fluorescence so that the Bdellovibrio cells could be seen. Andrew Fenton, a UK BBSRC funded PhD student, then used these strains and a new microscopic stage to follow Bdellovibrio cell division inside prey bacteria. He made timelapse videos and saw that the cell division was synchronous, once a long filamentous Bdellovibrio had grown and consumed all the prey nutrients. This division yielded the odd and even numbers of Bdellovibrio progeny that Dr Kanna had visualised through the microscope.
The findings tell us more about how Bdellovibrio consume prey bacterial contents, something that is useful in an anti-pathogen context. It has also illuminated a new way that bacteria grow and divide.
Figure: Bdellovibrio filamentous growth-phase cells septate synchronously within the bdelloplast, forming both odd and even numbers of progeny - sketch showing key points in Bdellovibrio cell development within a bdelloplast. Taken from FIG. 1. (Fenton et al., Journal Of Bacteriology, Dec. 2010, Vol 192,p. 6329–6335.)