Laser ablation of persistent twist cells in Drosophila: muscle precursor fate is not segmentally restricted

Development ◽  
1999 ◽  
Vol 126 (2) ◽  
pp. 273-280 ◽  
Author(s):  
E.R. Farrell ◽  
H. Keshishian
Keyword(s):  
Transcription Factor ◽  
Laser Ablation ◽  
Muscle Fiber ◽  
Peripheral Nerves ◽  
Abdominal Segment ◽  
Muscle Fibers ◽  
Normal Numbers ◽  
Developmental Potential ◽  
Lateral Muscle ◽  
Adjacent Segments

In Drosophila the precursors of the adult musculature arise during embryogenesis. These precursor cells have been termed Persistent Twist Cells (PTCs), as they continue to express the transcription factor Twist after that gene ceases expression elsewhere in the mesoderm. In the larval abdomen, the PTCs are associated with peripheral nerves in stereotypic ventral, dorsal, and lateral clusters, which give rise, respectively, to the ventral, dorsal, and lateral muscle fiber groups of the adult. We tested the developmental potential of the PTCs by using a microbeam laser to ablate specific clusters in larvae. We found that the ablation of a single segmental PTC cluster does not usually result in the deletion of the corresponding adult fibers of that segment. Instead, normal or near normal numbers of adult fibers can form after the ablation. Examination of pupae following ablation showed that migrating PTCs from adjacent segments are able to invade the affected segment, replenishing the ablated cells. However, the ablation of homologous PTCs in multiple segments does result in the deletion of the corresponding adult muscle fibers. These data indicate that the PTCs in an abdominal segment can contribute to the formation of muscle fibers in adjacent abdominal segments, and thus are not inherently restricted to the formation of muscle fibers within their segment of origin.

scholarly journals Frozen/thawed meat quality associated with muscle fiber characteristics of porcine longissimus thoracis et lumborum, psoas major, semimembranosus, and semitendinosus muscles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Huilin Cheng ◽  
Sumin Song ◽  
Gap-Don Kim
Keyword(s):  
Meat Quality ◽  
Muscle Fiber ◽  
Shear Force ◽  
Muscle Fibers ◽  
Frozen Storage ◽  
Meat Color ◽  
Pork Meat ◽  
Psoas Major ◽  
The Relationship

AbstractTo evaluate the relationship between muscle fiber characteristics and the quality of frozen/thawed pork meat, four different muscles, M. longissimus thoracis et lumborum (LTL), M. psoas major (PM), M. semimembranosus (SM), and M. semitendinosus (ST), were analyzed from twenty carcasses. Meat color values (lightness, redness, yellowness, chroma, and hue) changed due to freezing/thawing in LTL, which showed larger IIAX, IIX, and IIXB fibers than found in SM (P < 0.05). SM and ST showed a significant decrease in purge loss and an increase in shear force caused by freezing/thawing (P < 0.05). Compared with LTL, SM contains more type IIXB muscle fibers and ST had larger muscle fibers I and IIA (P < 0.05). PM was the most stable of all muscles, since only its yellowness and chroma were affected by freezing/thawing (P < 0.05). These results suggest that pork muscle fiber characteristics of individual cuts must be considered to avoid quality deterioration during frozen storage.

scholarly journals FINE STRUCTURE OF RAT INTRAFUSAL MUSCLE FIBERS

1971 ◽  
Vol 51 (1) ◽  
pp. 83-103 ◽  
Author(s):  
William K. Ovalle
Keyword(s):  
Muscle Fiber ◽  
Muscle Fibers ◽  
Muscle Spindles ◽  
Intrafusal Muscle ◽  
Dense Granules ◽  
Intrafusal Muscle Fibers ◽  
Sarcotubular System ◽  
Nuclear Chain ◽  
T System ◽  
Nuclear Bag

An ultrastructural comparison of the two types of intrafusal muscle fibers in muscle spindles of the rat was undertaken. Discrete myofibrils with abundant interfibrillar sarcoplasm and organelles characterize the nuclear chain muscle fiber, while a continuous myofibril-like bundle with sparse interfibrillar sarcoplasm distinguishes the nuclear bag muscle fiber. Nuclear chain fibers possess well-defined and typical M bands in the center of each sarcomere, while nuclear bag fibers contain ill-defined M bands composed of two parallel thin densities in the center of the pseudo-H zone of each sarcomere. Mitochondria of nuclear chain fibers are larger and more numerous than they are in nuclear bag fibers. Mitochondria of chain fibers, in addition, often contain conspicuous dense granules, and they are frequently intimately related to elements of the sarcoplasmic reticulum (SR). Striking differences are noted in the organization and degree of development of the sarcotubular system. Nuclear bag fibers contain a poorly developed SR and T system with only occasional junctional couplings (dyads and triads). Nuclear chain fibers, in contrast, possess an unusually well-developed SR and T system and a variety of multiple junctional couplings (dyads, triads, quatrads, pentads, septads). Greatly dilated SR cisternae are common features of nuclear chain fibers, often forming intimate associations with T tubules, mitochondria, and the sarcolemma. Such dilatations of the SR were not encountered in nuclear bag fibers. The functional significance of these structural findings is discussed.

Developmental potential of neural crest-derived cells migrating from segments of developing quail bowel back-grafted into younger chick host embryos

Development ◽  
1990 ◽  
Vol 109 (2) ◽  
pp. 411-423 ◽  
Author(s):  
T.P. Rothman ◽  
N.M. Le Douarin ◽  
J.C. Fontaine-Perus ◽  
M.D. Gershon
Keyword(s):  
Neural Crest ◽  
Neural Tube ◽  
Peripheral Nerves ◽  
Sympathetic Ganglia ◽  
Limb Bud ◽  
Pigment Cells ◽  
Developmental Potential ◽  
Migratory Experience ◽  
Host Embryo

The technique of back-transplantation was used to investigate the developmental potential of neural crest-derived cells that have migrated to and colonized the avian bowel. Segments of quail bowel (removed at E4) were grafted between the somites and neural tube of younger (E2) chick host embryos. Grafts were placed at a truncal level, adjacent to somites 14–24. Initial experiments, done in vitro, confirmed that crest-derived cells are capable of migrating out of segments of foregut explanted at E4. The foregut, which at E4 has been colonized by cells derived from the vagal crest, served as the donor tissue. Comparative observations were made following grafts of control tissues, which included hindgut, lung primordia, mesonephros and limb bud. Additional experiments were done with chimeric bowel in which only the crest-derived cells were of quail origin. Targets in the host embryos colonized by crest-derived cells from the foregut grafts included the neural tube, spinal roots and ganglia, peripheral nerves, sympathetic ganglia and the adrenals, but not the gut. Donor cells in these target organs were immunostained by the monoclonal antibody, NC-1, indicating that they were crest-derived and developing along neural or glial lineages. Some of the crest-derived cells (NC-1-immunoreactive) that left the bowel and reached sympathetic ganglia, but not peripheral nerves or dorsal root ganglia, co-expressed tyrosine hydroxylase immunoreactivity, a neural characteristic never expressed by crest-derived cells in the avian gut. None of the cells leaving enteric back-grafts produced pigment. Cells of mesodermal origin were also found to leave donor explants and aggregate in dermis and feather germs near the grafts. These observations indicate that crest-derived cells, having previously migrated to the bowel, retain the ability to migrate to distant sites in a younger embryo. The routes taken by these cells appear to reflect, not their previous migratory experience, but the level of the host embryo into which the graft is placed. Some of the population of crest-derived cells that leave the back-transplanted gut remain capable of expressing phenotypes that they do not express within the bowel in situ, but which are appropriate for the site in the host embryo to which they migrate.

A semi-automated measurement of muscle fiber size using the Imaris software

2021 ◽  
Author(s):  
Jennifer E. Gilda ◽  
Joon-Hyuk Ko ◽  
Aviv-Yvonne Elfassy ◽  
Nadav Tropp ◽  
Anna Parnis ◽  
...  
Keyword(s):  
Muscle Atrophy ◽  
Muscle Fiber ◽  
Cross Sections ◽  
Statistical Tests ◽  
Muscle Fibers ◽  
Fluorescent Labeling ◽  
Cross Sectional ◽  
Short Period ◽  
Fiber Size ◽  
Specific Protease

The size and shape of skeletal muscle fibers are affected by various physiological and pathological conditions, such as muscle atrophy, hypertrophy, regeneration, and dystrophies. Hence, muscle fiber cross-sectional area (CSA) is an important determinant of muscle health and plasticity. We adapted the Imaris software to automatically segment muscle fibers based on fluorescent labeling of the plasma membrane, and measure muscle fiber CSA. Analysis of muscle cross sections by the Imaris semi-automated and manual approaches demonstrated a similar decrease in CSA of atrophying muscles from fasted mice compared with fed controls. In addition, we previously demonstrated that downregulation of the Ca2+-specific protease calpain-1 attenuates muscle atrophy. Accordingly, both the Imaris semi-automated and manual approaches showed a similar increase in CSA of fibers expressing calpain-1 shRNA compared with adjacent non-transfected fibers in the same muscle cross section. Although both approaches seem valid for measurements of muscle fiber size, the manual marking method is less preferable because it is highly time-consuming, subjective, and limits the number of cells that can be analyzed. The Imaris semi-automated approach is user-friendly, requires little training or optimization, and can be used to efficiently and accurately mark thousands of fibers in a short period of time. As a novel addition to the commonly used statistics, we also describe statistical tests that quantify the strength of an effect on fiber size, enabling detection of significant differences between skewed distributions that would otherwise not be detected using typical methods.

Motoneuron and muscle fiber succinate dehydrogenase activity in control and overloaded plantaris

1991 ◽  
Vol 71 (4) ◽  
pp. 1589-1592 ◽  
Author(s):  
G. R. Chalmers ◽  
R. R. Roy ◽  
V. R. Edgerton
Keyword(s):  
Succinate Dehydrogenase ◽  
Muscle Fiber ◽  
Muscle Fibers ◽  
Cell Types ◽  
Mitochondrial Proteins ◽  
Succinate Dehydrogenase Activity ◽  
Fiber Size ◽  
The Right ◽  
Gastrocnemius Muscles ◽  
Selective Increase

To determine the level of coordination in succinate dehydrogenase (SDH) activity between plantaris motoneurons and muscle fibers, the soleus and gastrocnemius muscles were bilaterally excised in four cats to subject the plantaris to functional overload (FO). Five normal cats served as controls. Twelve weeks after surgery the right plantaris in each cat was injected with horseradish peroxidase to identify plantaris motoneurons. SDH activity then was measured in a population of plantaris motoneurons and muscle fibers in each cat. Control motoneurons and muscle fibers had similar mean SDH activities and a similar relationship between cell size and SDH activity. After FO, muscle fiber size doubled and mean muscle fiber SDH activity halved. Motoneuron mean SDH activity and size were unaffected by FO. Total SDH activity was unchanged in both the motoneurons and muscle fibers after FO. These changes suggest a selective increase in contractile proteins with little or no modulation of mitochondrial proteins in the muscle fibers, because total SDH activity was unchanged in muscle fibers after FO. These data demonstrate that although mean SDH activities were similar in control motoneurons and muscle fibers, mean SDH activities in these two cell types can change independently.

Exercise-induced focal skeletal muscle fiber degeneration and capillary morphology

1989 ◽  
Vol 66 (6) ◽  
pp. 2857-2865 ◽  
Author(s):  
F. M. Peeze Binkhorst ◽  
H. Kuipers ◽  
J. Heymans ◽  
P. M. Frederik ◽  
D. W. Slaaf ◽  
...  
Keyword(s):  
Blood Flow ◽  
Muscle Fiber ◽  
Cross Sections ◽  
Muscle Fibers ◽  
Basal Membrane ◽  
Cross Sectional ◽  
Male Wistar Rats ◽  
Muscle Water Content ◽  
Exercise Muscle ◽  
Exercise Induced

The relationship between exercise-induced focal muscle fiber degeneration and changes in capillary morphology was investigated in male Wistar rats. Untrained animals ran on a treadmill for 1 h at submaximal intensity and were killed 0, 6, or 24 h after running. Nonexercised rats served as controls. In situ perfused soleus muscles were prepared for electron microscopy. Micrographed cross sections were quantitatively analyzed for parameters indicative of capillary blood flow or transcapillary exchange. Capillary lumina were ovally rather than circularly shaped, and no indications for obstruction of blood flow at the capillary level were found. Endothelial cells and their organelles had a normal appearance in all groups. However, immediately after exercise, capillaries showed a decreased thickness of their endothelium and basal membrane, probably caused by dehydration. Six hours after exercise, muscle fibers were swollen (28% increase in cross-sectional area), resulting in a slightly increased diffusion distance. This fiber swelling was not associated with an increase in muscle water content, a finding for which no explanation could be found. Twenty-four hours after the animals ran, capillaries located near degenerated muscle fibers had an increased cross-sectional luminal area and an increased luminal circumference. This effect decreased gradually with increasing distance from the degenerated fiber area. The present morphometric results do not support the hypothesis that changes in capillary morphology primarily contribute to exercise-induced focal muscle fiber degeneration.

Structure and innervation of the swim bladder musculature in the weakfish, Cynoscion regalis (Teleostei: Sciaenidae)

1982 ◽  
Vol 60 (8) ◽  
pp. 1955-1967 ◽  
Author(s):  
R. Dana Ono ◽  
Stuart G. Poss
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Muscle Fiber ◽  
Muscle Fibers ◽  
Postsynaptic Membrane ◽  
Motor Endplate ◽  
Central Core ◽  
Swim Bladder ◽  
Motor Endplates ◽  
Cynoscion Regalis

The striated swim bladder muscles of the weakfish Cynoscion regalis are deep red in color but cannot be classified histologically as having typical red fibers. The muscle fibers are homogeneous and average 29.6 ± 5.3 μm in diameter, one-fifth the diameter of the adjacent hypaxialis fibers. Each muscle fiber contains thin, ribbonlike myofibrils which are radially arranged around a central core of mitochondria, glycogen, and sarcoplasmic reticulum. Myofibrils are extremely regular in pattern. Triads occur at the Z line. Numerous mitochondria and muscle nuclei are located at the periphery of each muscle fiber. The muscle fibers are multiply innervated with motor endplates distributed along their entire lengths. Well-developed folding of the postsynaptic membrane, not previously reported in fishes, is present at the motor endplate.

Anisotropic diffusion of oxygen in slices of rat muscle

1984 ◽  
Vol 246 (1) ◽  
pp. R107-R113 ◽  
Author(s):  
L. D. Homer ◽  
J. B. Shelton ◽  
C. H. Dorsey ◽  
T. J. Williams
Keyword(s):  
Diffusion Coefficient ◽  
Fluorescence Quenching ◽  
Muscle Fiber ◽  
Extracellular Space ◽  
Anisotropic Diffusion ◽  
Muscle Fibers ◽  
Rat Muscle ◽  
Hamstring Muscles ◽  
Standard Deviations ◽  
Diffusion Coefficient Of Oxygen

The diffusion coefficient of oxygen (D) and the fluorescence quenching coefficient (K') of pyrenebutyric acid (PBA) were measured in sections of rat hamstring muscles. Values of D and K' at temperatures (Tc) of 20, 30, and 40 degrees C were determined and referred to the values in water. In sections cut parallel to the muscle fibers, D = DH2O (0.380 +/- 0.038), whereas in sections cut across the grain of the fibers, D = DH2O (0.985 +/- 0.039). Oxygen diffuses along the length of a muscle fiber over twice as rapidly as it diffuses in directions perpendicular to the long axis of the fiber. This suggests that fibers, myofibrils, or myofilaments offer substantial barriers to the diffusion of oxygen, whereas extracellular space and spaces around fibers or myofibrils or myofilaments offer no more resistance than water to the diffusion of oxygen. Corresponding estimates for K' were K' = K'H2O[0.14 (1 + 0.25 Tc)] and K' = K'H2O[0.21 (1 + 0.25 Tc)] for slices cut parallel to the long axis of muscle fibers and across the long axis, respectively. Standard deviations of K' were 9%.

scholarly journals The Hippo pathway controls myofibril assembly and muscle fiber growth by regulating sarcomeric gene expression

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Aynur Kaya-Çopur ◽  
Fabio Marchiano ◽  
Marco Y Hein ◽  
Daniel Alpern ◽  
Julie Russeil ◽  
...  
Keyword(s):  
Gene Expression ◽  
Muscle Fiber ◽  
Flight Muscle ◽  
Hippo Pathway ◽  
Muscle Fibers ◽  
Muscle Growth ◽  
Fiber Growth ◽  
Flight Muscles ◽  
Sarcomeric Gene ◽  
The Hippo Pathway

Skeletal muscles are composed of gigantic cells called muscle fibers, packed with force-producing myofibrils. During development the size of individual muscle fibers must dramatically enlarge to match with skeletal growth. How muscle growth is coordinated with growth of the contractile apparatus is not understood. Here, we use the large Drosophila flight muscles to mechanistically decipher how muscle fiber growth is controlled. We find that regulated activity of core members of the Hippo pathway is required to support flight muscle growth. Interestingly, we identify Dlg5 and Slmap as regulators of the STRIPAK phosphatase, which negatively regulates Hippo to enable post-mitotic muscle growth. Mechanistically, we show that the Hippo pathway controls timing and levels of sarcomeric gene expression during development and thus regulates the key components that physically mediate muscle growth. Since Dlg5, STRIPAK and the Hippo pathway are conserved a similar mechanism may contribute to muscle or cardiomyocyte growth in humans.

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