Periodic, moderate water flow reversibly increases hair bundle density and size in .

Animals employ hair bundles on hair cells to detect flow, vibrations and gravity. Hair bundles on sea anemone tentacles detect nearby vibrations in the water column produced by prey movements and then regulate discharge of cnidae to capture prey. This study investigated: (1) the progressive effects of periodic water flow on hair bundle morphology and density of hair bundles and cnidae in sea anemones, (2) the reversibility of the flow response and (3) the ability of the response to be expedited with increased flow duration.

Evidence for involvement of TRPA1 in the detection of vibrations by hair bundle mechanoreceptors in sea anemones.

A homolog of TRPA1 was identified in the genome of the anemone, Nematostella vectensis (nv-TRPA1a), and predicted to possess six ankyrin repeat domains at the N-terminus and an ion channel domain near the C-terminus. Transmembrane segments of the ion channel domain are well conserved among several known TRPA1 polypeptides. Inhibitors of TRPA1 including ruthenium red decrease vibration-dependent discharge of nematocysts in N.

Cadherin 23-like polypeptide in hair bundle mechanoreceptors of sea anemones.

We investigated hair bundle mechanoreceptors in sea anemones for a homolog of cadherin 23. A candidate sequence was identified from the database for Nematostella vectensis that has a shared lineage with vertebrate cadherin 23s. This cadherin 23-like protein comprises 6,074 residues.

The involvement of arl-5b in the repair of hair cells in sea anemones.

The subcellular processes involved in repair of hair cells are not well understood. Sea anemones repair hair bundle mechanoreceptors on their tentacles after severe trauma caused by 1-h exposure to calcium-depleted seawater. Repair is dependent on the synthesis and secretion of large protein complexes named "repair proteins.

Hair bundle motility induced by chemoreceptors in anemones.

Most hair bundles are essentially fixed with respect to frequency specificity. However, hair bundles in sea anemones are dynamically tuned by actin-dependent changes in length. Tuning to low frequencies is accomplished by activation of chemoreceptors to N-acetylated sugars resulting in hair bundle elongation.