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SUMMARY:Algae\, bacteria and B vitamins  - Matt Cooper
DTSTART:20130523T153000Z
DTEND:20130523T160000Z
UID:TALK44295@talks.cam.ac.uk
CONTACT:Megan Cooper
DESCRIPTION:B vitamins are a large group of water soluble molecules that a
 ct as vital co-factors in many cellular metabolic processes. In the marine
  environment B vitamins are present in low concentrations and have been sh
 own to be important limiting factors for algal growth. With an estimated h
 alf of all microalgal species requiring an exogenous source of cobalamin (
 vitamin B12)\, one quarter requiring thiamine (B1) and a tenth requiring b
 iotin (B7)\, most algal species are auxotrophic for at least one member of
  the B vitamin family. Previous work in our laboratory has shown that alga
 e can form a mutualistic interaction with bacteria for one of these limiti
 ng B vitamins. We have demonstrated an algal-bacterial symbiosis between t
 he B12-dependent green alga Lobomonas rostrata and the soil bacteria Mesor
 hizobium loti\, in which bacteria provide B12 in return for fixed carbon f
 rom the alga. One aim of my PhD project was to identify a marine model for
  a similar mutualistic interaction between two species of genome sequenced
  and ecologically relevant algae and bacteria. I have been able to establi
 sh this model symbiosis between the cosmopolitan marine alga Ostreococcus 
 tauri\, which requires both B12 and B1 for growth\, and the bacterium Dino
 roseobacter shibae.\n\nThe main aim of this talk will be to describe this 
 mutualistic interaction between D. shibae and O. tauri in both B12 and thi
 amine limited conditions. This mutualism is stable over multiple generatio
 ns and sub-cultures and even persists in media containing no B vitamin sup
 plements\, which is notable as D. shibae itself requires an exogenous sour
 ce of biotin\, niacin (B3) and p-aminobenzoic acid (B10) indicating that v
 itamin traffic is not all one way. I will also describe currently on-going
  work to screen 16 ecotypes of O. tauri for naturally occurring mutualisti
 c bacteria and future work into the search for communication molecules tha
 t may mediate the symbiosis between the two species. This mutualism shows 
 that there is a complex interaction for B vitamins in certain marine micro
 organisms\, which may have important implications for marine phytoplankton
  ecology as well as the widespread evolution of vitamin auxotrophy in the 
 algal lineage. 
LOCATION:Biffen Lecture Theater\, Department of Genetics
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