Reconstruction of the Two - dimensional Birefringence Map of the Skeletal Muscle Sarcomere in Relaxed and Rigor States by Interference Microscopy Data

A ncw rnethod-automated quantitativc intcrfcrometry-was proposed for studying thc bircfiingencc in str iatcd muscle f ibcrs. On the basis of a Linnik microscopc, a sctup was dcsigned; this sctup givcs a phasc irnagc, which is a two-dirncnsfonal birefr ingcnce map. For thc f irst t imc, twoand thrccdimensional maps wcre obtained for thc total birefr ingcncc and the birefr ingcncc in singlc sarcomeres in thc ccntral part of f ibcrs ovcr a largc pixcl array. The total birefr ingencc in f ibcrs of the resting length in thc rigor statc proved to be lower than that in thc rclaxed statc. A calculat ion ofthe birefr ingencc by data ofthc intcrferencc patterns of single sarcorncrcs also showcd that thc nonnalizcd birefr ingcncc in A-disks in thc relaxed statc cxceeds that in the r igor statc. Thc rcsults obtaincd can bc cxplained by a dccrcasc in thc anisotropy of thc thick f i lamcnt becausc of thc departurc of tnyosin hcads f iom thc rnolccular corc in thc f lbcr r igorization. Kal ' v '1s1'r1t: intcrfcrcnce, bircf i ingcncc, tnusclc, sarcomcrc, r igor statc, rclaxcd statc skcletal musclc fibcr, to calculatc thc bircfi ingcncc fiom this pattcrn, and to rcconstruct thc two-dirncnsional rnap of the birefringencc in the sarcorncrc in two stationary phases of the interaction of uryosin hcads with actin. Unlike previous studies of the bircfringence of entire muscle fibers [ 4], this investigation involved local measurements of the birefringcnce in the central segments of single fibers and single sarcomercs in their structure.