Stentor coeruleus

Overview

Stentor coeruleus is a ciliate with a conspicuous arrangement of structures within one cell. At roughly a millimetre in length in the 2014 study’s introduction, it is large enough for individual cells to be manipulated surgically. A dense anterior band of cilia forms the oral apparatus, sweeping living prey towards the mouth, while a posterior holdfast permits temporary attachment. Ciliated rows extend along the body. These organised regions give the cell an anterior–posterior axis without requiring a multicellular body composed of separate tissues.

Slabodnick and colleagues investigated how this organisation is maintained and rebuilt. Their laboratory cells came from a commercial supplier and were cultured in the dark at 20°C. They were normally fed Chlamydomonas reinhardtii, an algal prey with a known genome. For gene-silencing experiments, the researchers instead supplied engineered Escherichia coli expressing double-stranded RNA against selected Stentor genes. This establishes a controlled experimental route to interfere with gene expression; it does not describe an ordinary ecological partnership between those bacteria and wild Stentor.

The study focused on Mob1, a conserved kinase-regulating protein. Antibody staining showed substantial localization near the posterior, with changes during division that preceded formation of a new posterior region in one daughter cell. RNA interference reduced Mob1 transcript levels and produced abnormal proportions, elongated forms and, later, cells with multiple oral or tail-like structures. Time-lapse observations of twenty cells over fifty-two hours recorded these changes without cell division, arguing against repeated failed cytokinesis as the explanation for those particular abnormalities. The experiments support a role in spatial patterning as well as division-related processes.

Microsurgery provided another test. After bisection, control fragments regenerated the missing structures, whereas many Mob1-depleted fragments formed misplaced oral apparatuses or ectopic tails. Ten percent in one twenty-cell experiment restored the missing apparatus and holdfast but still had abnormal proportions. The researchers interpreted this as potentially incomplete knockdown and different sensitivity of shape and polarity to depletion. A further experiment removed the cell ends where residual Mob1 remained, accelerating defects that otherwise appeared later. These results distinguish reduced RNA from slower loss of existing protein. They demonstrate requirements for normal regeneration under the tested conditions, rather than identifying every molecular interaction that establishes a body axis. Proposed conserved partner pathways and the full set of other localized regulators remained unresolved.

Origins & earliest records

A living ciliate represented by a commercially supplied laboratory culture in the selected 2014 study. Publication and experimental development are not dates for the species’ evolutionary origin.

Evidence & interpretation

RNA measurements, antibody localization, time-lapse imaging and surgical perturbation provide complementary evidence. Protein turnover, variable knockdown and sample-specific outcomes constrain interpretation; no raw-image or code reanalysis is claimed.

Selected bibliography

Documented works and useful reading. This is not a list of every appearance.

1. 01

   The Kinase Regulator Mob1 Acts as a Patterning Protein for Stentor Morphogenesis

   Mark M. Slabodnick, J. Graham Ruby, Joshua G. Dunn, Jessica L. Feldman, Joseph L. DeRisi and Wallace F. Marshall · 2014

   PLOS Biology 12(5): e1001861, 13 May. Complete main report, Materials and Methods and main textual captions; DOI 10.1371/journal.pbio.1001861. CC BY 4.0.

2. 02

   The Macronuclear Genome of Stentor coeruleus Reveals Tiny Introns in a Giant Cell

   Mark M. Slabodnick et al. · 2017

   Current Biology 27:569–575; selected in-press publisher PDF labels pages 1–7, dated 20 February 2017; publication notice 9 February. DOI 10.1016/j.cub.2016.12.057.

Family, evolution & connections

Located primary passages

Specific passages supporting details in this entry, grouped by their published witness.

References

Sources supporting this profile. Linked pages have their own scope and editorial standards.

1. ResearchThe Kinase Regulator Mob1 Acts as a Patterning Protein for Stentor MorphogenesisResearch access: 2026-10-05

Image credits

Brightfield micrograph of a single Stentor coeruleus cell with visible cortical stripes, photographed by Mark M. Slabodnick

This brightfield micrograph shows one Stentor coeruleus cell and its prominent cortical stripes. The source describes the feeding apparatus toward the top and attachment end toward the bottom. The figure supplies no scale bar, and this rounded cellular appearance is not the only shape the organism can assume.