By Alan Garcia
Beneficial skin bacteria in amphibians produce secondary metabolites that can inhibit the fungal pathogen Batrachochytrium dendrobatidis. Outbreaks of this fungus are thought to be responsible for the large worldwide decline of amphibians. The metabolites are thought to be a by-product of competition between skin bacterial species. To shed some light on this a group of researchers collected the cell free supernatant from bacterial cells collected from red-backed salamanders. Three different trials were done and tested for inhibition. The first trial contained single isolates, the second contained two combined isolates, and the third co-cultures. It was found that when bacteria are co-cultured they were a lot more inhibiting and only on this scenario emergent metabolites were produced. Metabolite tryptophol, the most active emergent metabolite against Bd was found and identified. This potent emergent metabolites may aid in the development of a combination of probiotics that work as an effective anti-fungal to diminish this detrimental disease wiping out the world's amphibian populations!
SEM micrograph of zoospore and sporangia of chytrid fungus (left), Image of red-back salamander (Plethodon cinereus)(right).
Left image by CSIRO via Wikipedia https://en.wikipedia.org/wiki/Chytridiomycota, right image by environmental education for kids via dnr.wi.gov http://dnr.wi.gov/eek/critter/amphibian/redback.htm.
Loudon AH, Holland JA, Umile TP, Burzynski EA, Minbole KPC, Harris RN, (2014). Interactions between amphibians' symbiotic bacteria cause the production of emergent anti-fungal metabolites, front microbiol 5: 441
Interesting. So, any ideas as to what it preventing this consortium of skin bacteria from being present in infected salamanders?
ReplyDelete