Research at Brandeis

 Research Movies

The following movies have been created using QuickTime. Download the QuickTime player if you don't have it.

Beating Myocyte Movie
(Birren Lab)
The movie shows a co-culture of rat sympathetic neurons and cardiac myocytes. In the animal, sympathetic innervation of the heart plays a key role in the modulation of cardiac function. This can also be seen in culture where the spontaneous beating of cardiac myocytes is altered by electrical stimulation of a connected sympathetic neuron. Neuronal stimulation results in the release of neurotransmitter from the neuron and the activation of myocyte receptors. By monitoring the beat rate of the cultured myocyte during neuronal stimulation we are able to use this culture system to investigate the role of neurotrophic factors in regulating the release of neurotransmitter from the sympathetic neurons.

QM/MM Calculations
Triose Phosphate Isomerase (TIM)
reaction movie (13 MB)
(Ringe-Petsko Lab)

 

The sequence of events in this movie are:

  • figure 2Diffusion of substrate DHAP into the active site of the enzyme
  • Transfer of a proton from the methylene group of DHAP to Glu 165 of TIM
  • His 95 facilitates proton transfer between two oxygens of the substrate
  • Final proton transfer and diffusion away from the enzyme

This movie shows an experiment from:

"Chi-sequence Recognition and DNA Translocation by Single RecBCD Helicase/Nuclease Molecules"
K. Dohoney and J. Gelles (2001)
Nature 409, pp. 370 - 374.

Windows video (.avi) format
Quicktime (.mov) format

The video is real time; the frame size is 6.5 µm wide by 6.6 µm tall.

figure 1The movie shows a bead-labeled RecBCD molecule translocating along a single DNA molecule. Initially, the free diffusion of beads in solution is seen. After a few seconds, one of the bead-labeled enzyme molecules attaches to the end of a DNA molecule at the center of the field (arrows); attachment is detected as the cessation of free diffusion and the commencement of characteristic tethered-particle Brownian motion in the vicinity of a single point on the microscope slide. Subsequent translocation of the enzyme along the DNA molecule is visualized as a gradual decrease in the spatial range of the Brownian motion; this decrease continues until the beads ceases visible movement altogether. This experiment was performed as shown in Fig. 1 of the paper, except that the ATP concentration was reduced to 10 µM to slow translocation.

 

Embryo Movie
(from the Welte Lab)

Early Drosophila embryos undergo drastic changes in their transparency during just a few hours. At first, they are completely opaque, then the periphery turns transparent, but later clouds up again. These changes in opacity are due to large scale transport of yolk storage organelles: cytoplasm filled with these organelles is opaque, cytoplasm depleted of them is clear. This property allows us to monitor the global distribution of organelles in living embryos.
In the periphery of early Drosophila embryos, lipid droplets show bi-directional motion along microtubules. They reverse direction every few seconds, alternately employing minus- and plus-end directed motors. Individual droplets can be followed in real time, and their motion can be analyzed with nanometer-scale precision.

 

 

 
415 South Street, Waltham, MA 02453 (781) 736-2000