Comment on

• Bead movement by single kinesin molecules studied with optical tweezers.

  Block SM, Goldstein LS, Schnapp BJ. Block SM, et al. Nature. 1990 Nov 22;348(6299):348-52. doi: 10.1038/348348a0. Nature. 1990. PMID: 2174512
• Force generation of organelle transport measured in vivo by an infrared laser trap.

  Ashkin A, Schütze K, Dziedzic JM, Euteneuer U, Schliwa M. Ashkin A, et al. Nature. 1990 Nov 22;348(6299):346-8. doi: 10.1038/348346a0. Nature. 1990. PMID: 2250707