Seminars

October 19 2016

12:00 LSB 2320

This seminar is sponsored by Depts of EEB MCDB and MiMg

Elizabeth Heath-Heckman
UC Berkeley

Bacterial and environmental cues are determinants of host-cell morphology and behavior in the squid-vibrio symbiosis Bacterial and environmental cues are determinants of host-cell morphology and behavior in the squid-vibrio symbiosis

Summary

Animals spend the majority of their lives in direct contact with bacterial cells, and we have only begun to understand the profound effects of beneficial bacteria on cellular and organismal development in their hosts. In the symbiosis between the Hawaiian bobtail squid \(Euprymna scolopes\) and its luminescent bacterial symbiont \(Vibrio fischeri\), bacterial products affect morphology both of single host cells and of entire organs. In the symbiotic organ, there is direct contact between host microvilli and bacterial cells, and the onset of symbiosis is known to increase microvillar density in the brush border. I will discuss my characterization of the daily microvillar dynamics and other day/night cycles in this system, and of the signaling molecules presented by bacterial symbionts that affect host cell morphology. Specifically, I have found that microvillar dynamics in the squid light organ are dependent upon the presentation of both exogenous light and bacterial lipopolysaccharide \(LPS\) to the host. This is the first evidence for the involvement of LPS in host microvillar density and this phenomenon may be common to many symbioses in which gram-negative bacteria contact polarized epithelia, such as the mammalian gut microbiome. Finally, I will discuss future directions in the squid-vibrio mutualism and my work characterizing symbiotic interactions in the pond leech Helobdella robusta, a well-known model for the study of organismal development.

 

 

 

 

 

 

 

 

 

 

 



 

 

 

 

 

 

 

 

 

 

 

 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



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