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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 32 (1967), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: SUMMARY— A study was made of the fine structure of myofibril suspensions prepared from seven heifers immediately after death and after various times post-mortem. Studies on myofibrils sampled immediately after death showed that sucrose isolation gave the best structural preservation as indicated by maintenance of Z-line structure. Although the appearance of resting muscle was maintained in both sucrose and KCI preparations, several myofibrils from the KCI-treated preparations showed stretched sarcomeres. Glycerol-treated myofibrils usually had shorter sarcomere lengths than myofibrils prepared with the other two solvents. Although fibrillar preservation seemed adequate when glycerol was used, Z-line structure was seldom well-preserved with glycerol.Myofibrils from muscle sampled 24 hr post-mortem at 2°C were supercontracted with thick filaments pushed against or through the Z-line, and no trace of l-bands remained. Myofibrils from muscle sampled 24 hr post-mortem at 16°C were contracted, but to a much lesser extent than 2°C-24 hr myofibrils. Storage at 2°C for 312 hr after death resulted in myofibrils that were contracted and that were structurally in a much poorer state of preservation than their 16°C counterparts. The 16°C-312 hr myofibrils were slightly contracted as indicated by the absence of H-zones and the presence of prominent, although narrowed, I-bands. All observations showed that shortening accompanying rigor mortis caused changes in banding patterns similar, and probably identical, to those predicted by Huxley's sliding filament model for contracting muscle.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 32 (1967), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The structural appearance of homogenized myofibril suspensions from seven heifers was studied using phase microscopy at various times post-mortem with three different extracting solutions: 1) 0.25M sucrose, 1mM ethylenedi-aminetetraacetic acid (EDTA), 0.05M Tris-(hydroxymethyl) aminomethane (Tris), pH 7.6; 2) 0.15M KCI, 1mM EDTA, 0.05M Tris, pH 7.6; and 3) 50% glycerol, 1miZl EDTA, 0.05M Tris, pH 7.6. Samples were examined at death and 24 hr and 312 hr post-mortem with storage at 2 and 16°C. The 16°-24-hr samples exhibited a marked thickening of the A-band, a shortening of the l-band, and a replacement of the H-zone by a dark line or band. The 2°.24-hr samples showed only alternating light and dark bands of nearly equal width, which has been described as a typical supercontracted pattern. At 312 hr, more variability in banding pattern and fragmentation is encountered, but the trend is to preserve the pattern observed in the 24.hr samples. Occasionally, a narrow H-zone is seen in the center of a thickened A-band in the glycerol preparations sampled 312 hr post-mortem. The results suggest that cold shortening of bovine muscle is structurally identical to contraction and substantiate the view that shortening is minimal at 16° storage temperatures.The sucrose extracting solution consistently gave the best preservation and was used for subsequent experiments. Although banding patterns at death and in the 24-hr samples obtained with glycerol showed reliable consistency, these preparations at times exhibited a disturbing fuzziness. Results with KCI solutions were least desirable, because of repeatedly poor structural preservation, as indicated by variability in sarcomere lengths within and between fibers, as well as lack of clarity in banding.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 271 (1978), S. 265-267 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Skeletal muscle containing nemaline rods was obtained by biopsy from a patient with congenital rod disease (second biopsy, case No. 1; see ref. 20 for clinical details) and stored at - 60 C until glycerination. It has been shown previously that glyceration does not alter fine structure of the ...
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0886-1544
    Keywords: intermediate filaments ; cytoskeleton ; filament attachment sites ; immunogold labeling ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The substructure of assembling cytoplasmic dense bodies (CDBs) and changes in the distribution of desmin and α-actinin during development of smooth muscle were studied in gizzard samples from 10- and 16-day embryos and from 1- and 7-day post-hatch chickens. CDBs in these cells lack the density of CDBs in mature or adult smooth muscle cells and, thus, allow observations of the changes inside CDBs. The random filament orientation seen in younger embryonic cells is first modified to include relatively small patches of IFs that are somewhat straighter and are approaching a side-by-side arrangement. As development proceeds, the IFs in these arrays become straighter, are parallel over longer lengths of the IFs and later acquire the density characteristic of mature CDBs. Anti-desmin labeling in embryonic 10- and 16-day cells showed that desmin intermediate filaments (IFs) were located in the myofilament compartment but were concentrated in or near assembling CDBs. Anti-desmin labeling shifted to the perimeter of CDBs after hatching. Cross sections, longitudinal sections, and stereo pairs all show that IF profiles are present inside unlabeled assembling CDBs. Anti-α-actinin labeling was directly on CDBs and was often associated with the cross-connecting filaments (CCFs) (average diameter of 2-3nm) inside CDBs. We propose, based on these data, that desmin IFs, α-actinin-containing CCFs, and actin filaments are the principal components of the substructure of assembling CDBs. We also present a proposed model for CDB assembly. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 11-18 
    ISSN: 0886-1544
    Keywords: intermediate filaments ; desmin ; cytoskeleton ; protein A-gold ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In avian smooth muscle cells, desmin-containing intermediate filaments (IFs) are a prominent component of the cytoskeleton and are readily seen in several domains, inclu-ding the axial intermediate filament bundle (IFB). Both the nucleus and some of the mitochondria are partly surrounded by elements of the IFB. By using anti-desmin and protein-A-colloidal gold labeling, we have identified intermediate filaments that form linkages with the nuclear envelope and with mitochondria. These linkage regions seem to occupy a proportionately greater part of the mitochondrial surface than of the nuclear envelope. The existence of these linkages in smooth muscle cells is consistent with results that support similar linkages to mitochondria and other cellular structures in various cells that contain either vimentin or keratin IFs. These linkages could functionally restrain or assist in homeostatically restoring organelles to their normal position after the rearrangement that accompanies the substantial shortening of smooth muscle cells.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 11 (1988), S. 117-125 
    ISSN: 0886-1544
    Keywords: protein A-gold ; dense bodies ; nucleus ; mitochondria ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To gain additional information about the arrangement of intermediate filaments (IF) in normal smooth muscle, fresh avian gizzard was processed for immunoelectron microscopy. The protein A-gold immunocytochemical technique was applied for the localization of desmin antigenic sites. Desmin-containing IFs were located in an axial bundle that partially surrounds the nucleus and were associated with numerous mitochondria near the poles of the nucleus. The bundle probably extends the length of the cell. Antibody labeling also showed concentrations of IF around and between cytoplasmic dense bodies (CDB) and also between CDB and membrane-associated dense bodies (MADB). The relationship between the axial bundle and the nucleus and associated mitochondria suggests that the bundle may support and define the position of these organelles in the cell. A fraying or branching of the bundle may integrate the bundle into the remaining cytoskeletal network of the cell.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Rat soleus muscle Z-lines and Z-line anomalies induced by neostigmine methyl sulfate (NMS) and cat soleus muscle Z-line and Z-line anomalies induced by tentomy were examined by electron microscopy before and after dissection of muscle fibers with Ca2+-activated neutral protease (CAF) to elucidate structural properties of Z-lines and related Z-line-type structures. In both normal and treated muscles, interdigitation of thin (6-7 nm) filaments, which were continuous with I-filaments (actin) from adjacent sarcomeres, was observed at the Z-line in longitudinal section.Both neostigmine methyl sulfate and tenotomy treatments induced muscle atrophy associated with Z-line degradation, streaming, and irregular distribution and accumulation of Z-line material and Z-rod formation. Tenotomized muscle also was characterized by the presence of N-line-like bands and I-Z-I brushes. CAF digestion removed the electron-dense covering material from Z-rods and revealed a backbone of actin filaments. The origin of Z-rods, their structural similarity to Z-lines in longitudinal and cross section, and their susceptibility to CAF indicate that Z-rods are directly related to native Z-lines and are probably lateral polymers of a basic Z-line unit.The regular square net alignment (22 nm) of I-filaments (actin) in cross sections of I-Z-I brushes which contain no N-lines suggests that the I-square net arrangement near the Z-line is determined by Z-filament-actin filament interaction rather than by the N-line or other factors.The results suggest that I-filaments (actin) penetrate the mammalian Z-line and are Z-line constituents and that the width of Z-lines and the length of Z-rods are determined by the amount of overlap of actin filaments. The perpendicular periodicity of Z-rods and the zigzag-oblique arrowheadlike appearance seen in longitudinal section of Z-lines are attributed to α-actinin.
    Additional Material: 27 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 223 (1989), S. 252-256 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A functional dependency between the nongravid uterus and the ovaries is essential to luteolysis and the return to estrus in the pig. After mating of gilts, the corpora lutea develop, and they are required for the maintenance of pregnancy to a normal duration of about 114 days. Hysterectomy of luteal phase (day 6) nongravid gilts results in persistence of the corpora lutea to 150 days. We report that these corpora secrete greater quantities (P 〈 0.025) of progesterone than during the later half of gestation (days 54-108). Although aging corpora lutea remain functional for at least an additional 35 days, an abrupt reduction by half in progesterone secretion (16 ng/ml) occurs about day 114 in hysterectomized gilts that coincides with the prepartum decrease to basal serum levels (〈0.5 ng/ml) at parturition (day 114) and during lactation. Aging corpora lutea remain large (averaging 〉 450 mg) on days 124 and 136 in hysterectomized gilts, whereas they regress (averaging 〈 75mg) in the lactating dams. Mitochondria continue to increase in size in aging corpora lutea of hysterectomized gilts until day 136; in contrast, they decrease during the postpartum period in lactating dams. A precisely timed signal, possibly of ovarian origin or form the CNS and pituitary gland, entrains in hysterectomized and pregnant pigs at day 113 that results in marked shifts in relaxin and progesterone secretion. Progesterone secretion and mitochondrial features suggest that procine corpora lutea seem genetically controlled and are preprogrammed at estrus for the duration of pregnancy, regardless of the presence of conceptuses or absence of the uterus.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 95-105 
    ISSN: 1059-910X
    Keywords: Striated muscle ; Smooth muscle ; Antibodies ; Localization ; Colloidal gold ; Proteins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The muscle cell cytoskeleton is defined for this review as any structure or protein primarily involved in linking or connecting protein filaments to each other or to anchoring sites. In striated muscle, the M line connects thick filaments at their centers to adjacent thick filaments. Titin forms elastic filaments that extend from the M line to the Z line and may contribute to the resting tension properties of striated muscle. Nebulin forms inextensible filaments in skeletal muscle that are closely associated with thin filaments and that may provide a length template for thin filaments. Z lines anchor thin filaments from adjacent sarcomeres via the actin-binding function of α-actinin. Other proteins located at the Z line include Cap Z, Z-nin, Z protein, and zeugmatin. Intermediate filaments connect myofibrils to each other at the level of the Z line and to the sarcolemma at the Z- and possibly the M-line levels. Immunolocalization has identified the adhesion plaque proteins spectrin, vinculin, dystrophin, ankyrin, and talin at subsarcolemmal sites where they may be involved with filament attachment. Smooth muscle cell cytoskeletons are believed to include membrane associated dense bodies (MADBs), intermediate filaments, cytoplasmic dense bodies (CDBs), and perhaps a subset of actin filaments. MADBs contain a menu of attachment plaque proteins and anchor both thin filaments and intermediate filaments to the sarcolemma. CDBs are intracellular analogs of striated muscle Z lines and anchor thin filaments and intermediate filaments. © 1995 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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