Scientist Discovers Two New Amoebae Species in Motel Room Lab

Motel Room Discovery of Rare Photosynthetic Amoebae

While visiting North Carolina’s Outer Banks in May 2021, Van Etten collected a routine water sample from a roadside marsh. According to the University of Maryland, she frequently samples ordinary bodies of water like ponds and puddles rather than restricting her fieldwork to specialized research stations. Back at her $80 motel room, she examined the water using portable gear purchased for her Couch Microscopy project.

She spotted two tiny cells, each roughly 15 micrometres long, belonging to the rare photosynthetic amoeba genus Paulinella. This roadside observation initiated a multi-year investigation involving Andrew Willoughby, a postdoctoral researcher at Duke University, and John Burns of the Bigelow Laboratory for Ocean Sciences. The team returned to the region to gather more material from Roanoke Sound in Nags Head, transforming their temporary accommodation into a functional workspace.

Improvised Field Methods and Cell Isolation

Working in the Nags Head motel room required creative equipment modifications. The published study details how researchers isolated individual cells using pulled Pasteur pipettes, standard micropipettes, and handmade tools crafted by supergluing toothbrush bristles onto colored pencils. These improvised instruments allowed the scientists to physically separate fragile specimens from brackish samples where Paulinella appeared so infrequently that researchers rarely encountered more than a single cell per water drop.

After isolation, the team sorted selected cells for culturing, scanning electron microscopy, and genomic preparation. While attempts to establish long-term axenic cultures failed, some individual cells survived and divided for about a month in filtered ambient water and culture medium. This hands-on fieldwork enabled the team to document fine physical differences between the newly isolated specimens before running genomic tests.

Genomic Analysis of Paulinella marae and Paulinella murrayi

Microscopic and genomic evaluations confirmed that the two isolated forms represented distinct, previously undescribed species. The researchers named them Paulinella marae and Paulinella murrayi, distinguishing them by cell size, overall shape, and the precise arrangement and orientation of their silica scales. P. marae features an elongated, shell-like structure measuring roughly 15 to 19.1 micrometres long, with unique scale overlap patterns observed in waters holding a salinity of 10 to 14.

Genomic sequencing of their chromatophore and mitochondrial genomes revealed broadly conserved gene content alongside structural variations, including genome inversions and rearrangements. Phylogenetic analyses showed notable discrepancies between evolutionary trees built from nuclear data versus organelle data. The study’s authors noted these differences could stem from factors such as substitution saturation and limited taxon sampling, providing new avenues to study how cellular compartments evolve following major evolutionary transitions.

Broader Ecological Distribution and Future Research

The addition of P. marae and P. murrayi brings the total count of known photosynthetic Paulinella species to six. Based on observations gathered over multiple years in North Carolina alongside independent records from hobbyist microscopists and naturalists, the research team suggests these organisms are globally distributed but heavily under-sampled.

The study highlights the power of pairing traditional field observations with modern genomics. Researchers conclude that the North Carolina brackish site will remain a valuable geographic anchor for future studies investigating the population genetics, ecology, and evolutionary trajectories of primary plastid-containing amoebae.

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