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Microbes living with microbes

My work focuses on the unusual ciliate Kentrophoros and its ectosymbiotic bacteria. Kentrophoros are found in marine sediment (muds, fine sand) of coastal areas around the world. The bacterial symbionts are attached to the ciliate’s surface, and use chemical energy from the environment (sulfur-oxidizing chemoautotrophy) to build up biomass, which the ciliates harvest for food.

For more information, please see my institutional webpage at the Max Planck Institute for Marine Microbiology, where I work in the Symbiosis Department headed by Nicole Dubilier.


Seah BKB, Schwaha T, Volland J-M, Huettel B, Dubilier N, Gruber-Vodicka HR (2017) Specificity in diversity: single origin of a widespread ciliate-bacteria symbiosis. Proceedings of the Royal Society B 284 (1858): 20170764. [blog post]

Seah BKB, Gruber-Vodicka HR (2015) gbtools: Interactive visualization of metagenome bins in R. Frontiers in Microbiology 6: 1451. [GitHub page, blog post]

Past projects

This section is about projects that I’ve worked on in the past.

A symbiosis inside a symbiosis

For my undergraduate senior thesis, I studied a three-part symbiosis: The hosts are a family of marine invertebrates (sea squirts) the Molgulidae, which contain a protist (“protozoan”, or eukaryotic microbe) symbiont called Nephromyces. The protist, in turn, has bacteria that dwell inside its cells, making this a nested symbiosis, like a set of Russian dolls.

Molgula manhattensis, one of the host animal species

In my research, I used molecular methods to identify the bacteria living inside Nephromyces, because they cannot be directly cultivated. Nephromyces has recently been shown to be a member of the Apicomplexa, a protist phylum that includes medically-important species like Plasmodium, the malaria parasite.

My advisors for this project were Mary Beth Saffo at the Marine Biological Laboratory, Woods Hole, and Colleen Cavanaugh of Harvard University.

Support for my work came from various sources: The Harvard College Research Program, Museum of Comparative Zoology, the Herchel Smith Summer Undergraduate Research Fellowship, Microbial Sciences Initiative (MSI) at Harvard, and Harvard Life Sciences Education.

Work on the Nephromyces symbiosis is being continued by Chris Paight and Chris Lane at the University of Rhode Island, and Sergio Muñoz and Claudio Slamovits at Dalhousie University.


Carl Zimmer has blogged about Dr Saffo’s research on this symbiosis for Discover magazine.

I was featured as the Harvard Crimson’s Lab Rat of the Week in October 2010.

Further back…

I have previously done research on the ecology of animal sounds with Brian Farrell at Harvard, and on mosses with Benito Tan at the National University of Singapore. In the past I’ve worked for both the Singapore Botanic Gardens Herbarium and the Farlow Herbarium of Harvard University as a curatorial assistant.

Tan BC, Ho BC, Seah BKB (2004) Two new moss species, Trichosteleum fleischeri and Splachnobryum temasekensis, from Singapore. Journal of the Hattori Botanical Laboratory 96: 223-230.