Naegleria as an ameboflagellate

Naegleria grows and divides as an amoeba. When

stressed, Naegleria "transforms" into a flagellate. 

During this hour-long process, Naegleria forms an

entire microtubule cytoskeleton including flagella

and basal bodies (centrioles) from scratch. The

resulting flagellates are transitory; cells will return

to amoebae in several minutes to hours.   Cells can

also form resting cysts.

By studying which genes Naegleria uses during basal

body assembly, we have been able to identify

conserved genes in the centrioles of human cells,

including several that were previously uncharacterized

(Fritz-Laylin et. al, J Cell Sci. 2010 Dec 1;123:4024-31)


Naegleria is a single celled eukaryote found in mud and freshwater all over the world.  Naegleria can exist in three forms: a crawling amoeba, swimming flagellate, or dormant cyst.

Although most Naegleria species are harmless, one species (Naegleria fowleri) can cause severe amoebic meningitis if it happens to get into someone’s nose. 

Studying Naegleria has shed light on several fundamental aspects of biology, including early eukaryotic evolution and the assembly of cellular structures. 


What is Naegleria?

Naegleria amoeba

Naegleria flagellate

Naegleria sheds light on early eukaryotic evolution

Comparing the sequences of diverse free-living protists is essential for understanding eukaryotic evolution and molecular and cell biology. Naegleria belongs to a varied and ubiquitous protist clade (Heterolobosea) that diverged from other eukaryotic lineages over a billion years ago. The analysis of the 15,727 protein-coding genes encoded by Naegleria gruberi’s genome was published in March, 2010 (Fritz-Laylin et. al, Cell. 140(5):631-42).  This analysis included substantially broader phylogenomic comparisons of free-living eukaryotes than previously possible, allowing us to identify thousands of genes likely present in the pan-eukaryotic ancestor, with 40% likely eukaryotic inventions. The Naegleria genome, analyzed in the context of other protists, reveals a remarkably complex ancestral eukaryote with a rich repertoire of cytoskeletal, sexual, signaling, and metabolic modules.