Three-dimensional reconstruction of rigor insect flight muscle from tilted thin sections

Nature ◽  
1984 ◽  
Vol 310 (5975) ◽  
pp. 285-291 ◽  
Author(s):  
Kenneth A. Taylor ◽  
Mary C. Reedy ◽  
Leonidas Córdova ◽  
Michael K. Reedy
Keyword(s):  
Flight Muscle ◽  
Insect Flight ◽  
Three Dimensional ◽  
Three Dimensional Reconstruction ◽  
Insect Flight Muscle ◽  
Thin Sections ◽  
Dimensional Reconstruction

scholarly journals Three-dimensional reconstruction of the Z disk of sectioned bee flight muscle.

1989 ◽  
Vol 108 (5) ◽  
pp. 1761-1774 ◽  
Author(s):  
N Q Cheng ◽  
J F Deatherage
Keyword(s):  
Central Region ◽  
Actin Filaments ◽  
Flight Muscle ◽  
Three Dimensional ◽  
Opposite Polarity ◽  
Dimensional Structure ◽  
Three Dimensional Reconstruction ◽  
Thin Sections ◽  
Dimensional Reconstruction ◽  
Cross Links

The three-dimensional structure of the central region of the Z disk of honeybee flight muscle has been determined to a resolution of 70 A by three-dimensional reconstruction from electron micrographs of tilted thin sections. The reconstructions show a complex assembly in which actin filaments terminate and are cross-linked together; a number of structural domains of this network are resolved in quantitative three-dimensional detail. The central region of the Z disk contains two sets of overlapping actin filaments of opposite polarity, which originate in the sarcomeres adjacent to the Z disk, and connections between these filaments. The filaments are deflected by the attachment of cross-links; spacing between filaments change by greater than 100 A during their passage through the Z disk. Each actin filament is linked by connecting structures to four filaments of opposite polarity and two filaments are of the same polarity. Four types of connecting density domain are observed in association with pairs of filaments of opposite polarity: C1, C2, C3, and C5. Two of these, C3 and C5, are associated with the ends of actin filaments. Another connection, C4, is associated with three filaments of the same polarity; C4 is threefold symmetric.

scholarly journals Tomographic Three-dimensional Reconstruction of Insect Flight Muscle Partially Relaxed by AMPPNP and Ethylene Glycol

1997 ◽  
Vol 139 (3) ◽  
pp. 695-707 ◽  
Author(s):  
Holger Schmitz ◽  
Mary C. Reedy ◽  
Michael K. Reedy ◽  
Richard T. Tregear ◽  
Kenneth A. Taylor
Keyword(s):  
Ethylene Glycol ◽  
Flight Muscle ◽  
Insect Flight ◽  
Three Dimensional ◽  
Thick Filament ◽  
Power Stroke ◽  
Insect Flight Muscle ◽  
Target Zone ◽  
Dimensional Reconstruction ◽  
Myosin Subfragment 1

Rigor insect flight muscle (IFM) can be relaxed without ATP by increasing ethylene glycol concentration in the presence of adenosine 5′-[β′γ- imido]triphosphate (AMPPNP). Fibers poised at a critical glycol concentration retain rigor stiffness but support no sustained tension (“glycol-stiff state”). This suggests that many crossbridges are weakly attached to actin, possibly at the beginning of the power stroke. Unaveraged three-dimensional tomograms of “glycol-stiff” sarcomeres show crossbridges large enough to contain only a single myosin head, originating from dense collars every 14.5 nm. Crossbridges with an average 90° axial angle contact actin midway between troponin subunits, which identifies the actin azimuth in each 38.7-nm period, in the same region as the actin target zone of the 45° angled rigor lead bridges. These 90° “target zone” bridges originate from the thick filament and approach actin at azimuthal angles similar to rigor lead bridges. Another class of glycol-PNP crossbridge binds outside the rigor actin target zone. These “nontarget zone” bridges display irregular forms and vary widely in axial and azimuthal attachment angles. Fitting the acto-myosin subfragment 1 atomic structure into the tomogram reveals that 90° target zone bridges share with rigor a similar contact interface with actin, while nontarget crossbridges have variable contact interfaces. This suggests that target zone bridges interact specifically with actin, while nontarget zone bridges may not. Target zone bridges constitute only ∼25% of the myosin heads, implying that both specific and nonspecific attachments contribute to the high stiffness. The 90° target zone bridges may represent a preforce attachment that produces force by rotation of the motor domain over actin, possibly independent of the regulatory domain movements.

scholarly journals Three-dimensional image reconstruction of insect flight muscle. I. The rigor myac layer.

1989 ◽  
Vol 109 (3) ◽  
pp. 1085-1102 ◽  
Author(s):  
K A Taylor ◽  
M C Reedy ◽  
L Córdova ◽  
M K Reedy
Keyword(s):  
Thin Filament ◽  
Flight Muscle ◽  
Insect Flight ◽  
Three Dimensional ◽  
Bridge Structure ◽  
Insect Flight Muscle ◽  
Single Filament ◽  
Cross Bridge ◽  
Cross Bridges

We have obtained detailed three-dimensional images of in situ cross-bridge structure in insect flight muscle by electron microscopy of multiple tilt views of single filament layers in ultrathin sections, supplemented with data from thick sections. In this report, we describe the images obtained of the myac layer, a 25-nm longitudinal section containing a single layer of alternating myosin and actin filaments. The reconstruction reveals averaged rigor cross-bridges that clearly separate into two classes constituting lead and rear chevrons within each 38.7-nm axial repeat. These two classes differ in tilt angle, size and shape, density, and slew. This new reconstruction confirms our earlier interpretation of the lead bridge as a two-headed cross-bridge and the rear bridge as a single-headed cross-bridge. The importance of complementing tilt series with additional projections outside the goniometer tilt range is demonstrated by comparison with our earlier myac layer reconstruction. Incorporation of this additional data reveals new details of rigor cross-bridge structure in situ which include clear delineation of (a) a triangular shape for the lead bridge, (b) a smaller size for the rear bridge, and (c) density continuity across the thin filament in the lead bridge. Within actin's regular 38.7-nm helical repeat, local twist variations in the thin filament that correlate with the two cross-bridge classes persist in this new reconstruction. These observations show that in situ rigor cross-bridges are not uniform, and suggest three different myosin head conformations in rigor.

The interpretation of granitic textures from serial thin sectioning, image analysis and three-dimensional reconstruction

1995 ◽  
Vol 59 (395) ◽  
pp. 203-211 ◽  
Author(s):  
D. N. Bryon ◽  
M. P. Atherton ◽  
R. H. Hunter
Keyword(s):  
Image Analysis ◽  
Three Dimensional ◽  
Three Dimensional Reconstruction ◽  
Mineral Phase ◽  
Thin Sections ◽  
Thin Sectioning ◽  
Potential Problems ◽  
Dimensional Reconstruction ◽  
Textural Development

AbstractTextural development of the felsic phases in two granodioritic rocks from the zoned Linga superunit of the Peruvian Coastal Batholith has been characterized using serial thin sectioning, image analysis and three-dimensional reconstruction. The study has shown how each mineral phase contributed to the texture during the formation and development of a contiguous crystal framework and during subsequent restriction, isolation and occlusion of the melt-filled porosity. The work highlights the important factors and potential problems in the use of serial thin sections and imaging in the analysis of complex polyphase rock textures.

Three-Dimensional Reconstruction of Rabbit-DerivedPneumocystis cariniifrom Serial-Thin Sections II: Intermediate Precyst

1991 ◽  
Vol 38 (4) ◽  
pp. 407-411 ◽  
Author(s):  
FRANCOIS PALLUAULT ◽  
BRUNO PIETRZYK ◽  
EDUARDO DEI-CAS ◽  
CHRISTIAN SLOMIANNY ◽  
BENOIT SOULEZ ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Three Dimensional Reconstruction ◽  
Thin Sections ◽  
Dimensional Reconstruction

Structure of the insect flight muscle Z disk

1983 ◽  
Vol 41 ◽  
pp. 456-457
Author(s):  
Deatherage J.F. ◽  
Luke B. ◽  
Sainsbury G.M. ◽  
Bullard B.
Keyword(s):  
Flight Muscle ◽  
Insect Flight ◽  
Hexagonal Lattice ◽  
Unit Cell ◽  
Insect Flight Muscle ◽  
Thin Filaments ◽  
Thin Sections ◽  
Carpenter Bee ◽  
Contour Maps ◽  
Fourier Filtering

The Z disk of striated muscle is a regular planar network of connections linking two sets of oppositely directed thin filaments from adjacent sarcomeres. Ashurst has inspected images of oblique thin sections through insect Z disks, and proposed that parallel overlapping filaments in the Z disk are arranged in hexagonal bundles of six, which alternating filaments enter from opposite sarcomeres. We have now analyzed images of thin-sectioned and negatively-stained Z disks using Fourier filtering and crystallographic image processing methods. Our findings confirm the basic model of Ashurst for the arrangement of filaments inside the Z disk. By evaluating contour maps of crystallographically averaged images at higher resolution, we have obtained additional information about the positions of the filaments and the connections linking them.We have examined Z disks of flight muscles of three orders of insect, Diptera (blowfly), Hemiptera (Lethocerus) and Hymenoptera (bumble and carpenter bee). Thin sections from Lethocerus whole muscle fibers and negatively-stained isolated Z disks from bumble bee were examined in most detail. The connectivities of thin filaments of one sarcomere through the Z disk to the adjacent sarcomere were traced on Fourier-filtered images of oblique thin-sections. These cut the myofibril at an angle off perpendicular, intersecting it on one side of the Z disk, passing through it, and exiting on the other side. The filaments in the Z disk lattice, and the connections between them, were examined on crystallographically averaged images of transverse sections through the Z disk, and of isolated, negatively-stained Z disks.The insect flight muscle Z disk is arranged on a hexagonal lattice with unit cell dimensions of about 465Å. Images of both thin- sectioned and negatively-stained Z disks diffract optically to the fifth or sixth order (about 75Å resolution). The projection symmetry of the Z disk is p3m. Contour maps of crystallographically averaged images of thin- sectioned and isolated Z disks show prominent features arranged in roughly hexagonal bundles of six. These features correspond to extensions of the thin filaments into the Z disk, three from each of the opposing sarcomeres. By analysis of oblique sections we have confirmed that the opposed thin filament lattices of the two sarcomeres meet in three-fold to six-fold register (that is, a third of a unit cell out of register along both crystallographic axes). The relative strengths of features in these images are consistent with long overlap of filaments from opposite sarcomeres inside the Z disk.

Three-dimensional image reconstruction of rigor crossbridges in insect flight muscle (IFM)

1983 ◽  
Vol 41 ◽  
pp. 454-455
Author(s):  
K. Taylor ◽  
L. Cordova ◽  
M.C. Reedy ◽  
M.K. Reedy
Keyword(s):  
Fourier Transforms ◽  
Flight Muscle ◽  
Insect Flight ◽  
Three Dimensional ◽  
Image Data ◽  
Insect Flight Muscle ◽  
Single Filament ◽  
Thin Filaments ◽  
Filament Axis ◽  
Axis Parallel

Dorsal longitudinal IFM from the water bug Lethocerus indicus, was rigorized by glycerination. Fiber bundle 958 retained a good rigor x-ray diffraction pattern after a 5 step fixation embedding sequence which included glutaraldehyde-tannic acid fixation, OsO4-UrAc staining, ethanol dehydration and Araldite embedding.The MYAC single filament layer of insect flight muscle contains alternating thick and thin filaments and is found isolated within longitudinal sections about 250Å thick. For our 3-D reconstruction we selected a MYAC region which appeared homogenous (both sides equal) over nearly 3/4 of a half sarcomere. Two tilt series ranging through ±60° of tilt in 10° steps were obtained, with tilt axis parallel to the filament axis in one and perpendicular in the other. Fourier transforms were calculated from 256x256 point arrays.The tilt data were combined using procedures similar to those used for 2-D crystalline arrays except that we obtain both amplitudes and phases from the image data.

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