منابع مشابه
Control of Cellular Contraction by Calcium in Vorticella
1. Vorticella extracted with Triton X-100 contracted (i.e. the cell body shrank and the stalk coiled) when the external Ca2+ concentration was raised. The degree of contraction increased with increasing Ca2+ concentration. 2. The threshold Ca2+ concentration for shrinkage of the cell body was identical with that for coiling of the stalk in Vorticella extracted with Triton X-100. 3. Living Vorti...
متن کاملPower-limited contraction dynamics of Vorticella convallaria: an ultrafast biological spring.
Vorticella convallaria is one of the fastest and most powerful cellular machines. The cell body is attached to a substrate by a slender stalk containing a polymeric structure-the spasmoneme. Helical coiling of the stalk results from rapid contraction of the spasmoneme, an event mediated by calcium binding to a negatively charged polymeric backbone. We use high speed imaging to measure the contr...
متن کاملESPVR and the Mechanics of Ventricular Contraction
This study is written in a way to stress the importance of introducing the active force generated by the myocardium in the formalism describing the pressure-volume relation (PVR) in the left ventricle. Various clinical applications of the end-systolic pressure-volume relation (ESPVR) are also discussed. Attention is given to the calculation of the ejection fraction (EF) and the myocardial longi...
متن کاملTransmural myocardial mechanics during isovolumic contraction.
OBJECTIVES We sought to resolve the 3-dimensional transmural heterogeneity in myocardial mechanics observed during the isovolumic contraction (IC) phase. BACKGROUND Although myocardial deformation during IC is expected to be little, recent tissue Doppler imaging studies suggest dynamic myocardial motions during this phase with biphasic longitudinal tissue velocities in left ventricular (LV) l...
متن کاملEvaluation of the Mass Transfer Effect of the Stalk Contraction-Relaxation Cycle of <i>Vorticella convallaria</i>
Advisor: Sangjin Ryu Vorticella convallaria is a genus of protozoa living in fresh water. It has a bell-shaped zooid equipped with adoral ciliary bands and a contractile stalk tethering the zooid to a substrate. Vorticella is regarded as a biological spring because its contractile stalk can pull the zooid towards the substrate at a remarkably high speed and then relaxes to its extended state mu...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 2010
ISSN: 0006-3495
DOI: 10.1016/j.bpj.2010.03.023