The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 
 
 

Fluo-3 signals associated with potassium contractures in single amphibian muscle fibres.

1. The calcium-sensitive dye fluo-3 AM was used to obtain fluorescence signals and calcium transients associated with K+ contractures, twitches and tetani, in intact single muscle fibres of the tropical toad Leptodactylus insularis. 2. The changes in free calcium concentration in the myoplasm ([Ca2+]i) were calculated using the values of the 'off' (k- = 33.5 s-1) and 'on' (k+ = 13.1 microM-1 s-1) rate constants for the binding of calcium to the dye (dissociation constant, Kd = k-/k+). The mean (+/- S.E.M., n = 7) peak [Ca2+]i value during twitches or tetani was 3.9 +/- 0.3 or 4.1 +/- 0.3 microM, respectively, while during maximal K+ contractures, it was 10.3 +/- 0.8 microM. The threshold [Ca2+]i for tension development was about 1 microM. 3. For responses elicited with high [K+]o (80-190 mM), the calcium transients decayed faster than tension. At lower [K+]o (30-70 mM), the decay was slower, and relaxation was complete when [Ca2+]i was still above contractile threshold values. 4. Following a K+ contracture, recovery of the calcium transients associated with twitches occurred before recovery of tension, indicating an apparent dissociation between [Ca2+]i and tension output. This apparent dissociation between calcium and tension output could be attributed to the desensitization of the contractile proteins to calcium, or, more probably, to the non-uniform behaviour of calcium release and/or uptake sites, leading to an unhomogeneous distribution of active sarcomeres along the fibre length and localized sarcomere relaxation.[1]

References

 
WikiGenes - Universities