The metals iron and manganese play essential roles in life, as they are involved in many processes like respiration, metabolism and energy production. Although essential, they can also be dangerous if uncontrolled, as they can participate in chemical reactions that cause damage to organisms and cells, which can ultimately lead to death. Hence all forms of life have learned to control availability of iron and manganese, by balancing the acquisition, storage and usage.

The systems participating in iron and manganese acquisition, storage and usage are well known in bacteria associated with humans and animals, where bacteria and food sources are often present in close contact and high concentrations. Less is known about how this works in bacteria living in marine environments, as both the sources of metals like iron and manganese, but also the types of bacteria are very different from animal-associated bacteria.

In his PhD project, Rob Green has investigated the iron and manganese acquisition and control systems of Roseobacter bacteria, which are a model for the bacteria found in marine environments. This work, a collaborative project of the School of Biological Sciences of the University of East Anglia and the Institute of Food Research, has highlighted unique adaptations of marine bacteria to the conditions in their natural habitat, both for the metals iron and for manganese. Of interest is the link between the novel manganese transporter MntX detected in many marine bacteria, which has also been found in the important human pathogen Vibrio cholerae, which itself utilises a waterborne route of infection. This work highlights the potential gene flow between marine bacteria and human pathogens, and the importance of studying metal metabolism in marine bacteria.

Reference: Manganese uptake in marine bacteria; the novel MntX transporter is widespread in Roseobacters, Vibrios, Alteromonadales and the SAR11 and SAR116 clades, Robert Green et al, The ISME Journal doi: 10.1038/ismej.2012.140