Difference between revisions of "Nematocyte firing"

Revision as of 17:15, 1 December 2011

Background

• David Plachetzki discovered that phototransduction gene expression is associated with nematocyte cells. We hypothesized that light may modulate their firing, in addition to other sensory modalities which are already known to modulate firing. Dave and Caitlin Fong then developed experiments to test whether light modulates firing. They conducted Nematocyte Capture assays under different light intensities of blue light in Hydra, and found significant differences.

• Katia's thesis gives more extensive background about this Katia Jindrich 2011.

• Another important source is Dave's original paper Plachetzki nematocyte firing.

Unpublished Experiments

• At UCLA, David Gold and Caitlin Fong conducted firing assays in 2 blue light intensities for 2 new species: moon jelly (Aurelia aurita) and a sea anemone (Anthopleura).
  • Both Aurelia Fong's Aurelia data and Anthopleura Gold's Anthopleura data show higher firing rates in dim blue light compared to bright.
  • With Katia's experiments below, we now have 4 species from 3 Cnidarian classes with similar results. This suggests that dim light diminution may be an ancestral feature of Cnidaria.

• Katia visited for 6 months and conducted firing experiments in Haliplanella using combinations of light and mucin. Katia's thesis is here Katia Jindrich 2011.
  • Haliplanella shows the same pattern, firing more in dim blue light than bright.
  • In Haliplanella, light and mucin have opposing effects.

• Federico visited for 6 months and conducted experiments in Hydra to test combinations of G-protein inhibiting drug, light, and amino acids. Raw data are here [1] and here: [2]

• Dan did MSP on the Haliplanella symbionts to find that the absorbance peak is similar to an opsin peak.

The plan is to put these results into a paper right now referred to as The Data Dump Paper.

Next Step Experiments

• Adam aims to establish the behavioral action spectrum for nematocyte modulation. This involves measuring the nematocyte capture rate under different colors of light, but with standardized light intensity.
• We've shown that more nematocytes are captured in dim light. Does this translate to higher feeding rates? Todd and Tess Oakley plan to test this by adding a fixed number of Artemia, and counting survivors after a fixed period, under different light intensities. Tess' Plan. Data are being recorded here: [3] and can be edited here [4]. Haliplanella Feeding Rates