The relaxed crossbridge pattern in isolated rabbit psoas muscle thick filaments

1993 ◽  
Vol 105 (3) ◽  
pp. 841-848
Author(s):  
R.W. Kensler ◽  
M. Stewart
Keyword(s):  
Structural Difference ◽  
Psoas Muscle ◽  
Thick Filament ◽  
Rabbit Muscle ◽  
Fish Muscles ◽  
Thick Filaments ◽  
Filament Structure ◽  
The Individual ◽  
High Degree ◽  
Degree Of Similarity

Rabbit muscle is a major source of material for biochemical experiments and spin labelling studies of contraction, and so it is important to establish how closely this material resembles the frog and fish muscles usually used for structural studies. Previous studies have shown that relaxed rabbit muscle thick filaments lose the characteristic order of their crossbridges when they are cooled below about 15–19 degrees C, whereas the order of fish and frog muscles is retained above 0 degrees C. The lack of order has frustrated attempts to examine rabbit thick filament structure and has raised questions about how closely they might resemble other thick filaments. We have therefore developed a procedure for preserving the crossbridge order in isolated filaments. Electron microscopy of these thick filaments after either negative staining or metal shadowing has shown that the crossbridge pattern has a 43 nm axial repeat and is based on three near-helical strands. Computed transforms of either type of image show a series of layer lines confirming that the native relaxed pattern has been preserved, and computer reconstructions show the individual crossbridges lying on a slightly perturbed 3-stranded lattice. These data indicate an unexpectedly high degree of similarity between the rabbit and frog patterns and indicate that, in fully preserved material, there is little structural difference between the two thick filaments at the temperature at which each normally functions.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of the PCR-DGGE method in forensic microbiology

2016 ◽  
Vol 292 ◽  
pp. 59-64
Author(s):  
Aleksandra Ziembińska-Buczyńska ◽  
◽  
Krzysztof Kraśnicki ◽  
Keyword(s):  
Mobile Phones ◽  
Electronic Device ◽  
Screening Method ◽  
Electrophoresis Method ◽  
Forensic Microbiology ◽  
The Subject ◽  
Polymerase Chain ◽  
The Individual ◽  
High Degree ◽  
Degree Of Similarity

The latest reports on the subject of forensic microbiology indicate that it is possible to link a perpetrator of an offence to the evidence, based on molecular analysis of microbiological material. The microbiome of human epidermis is known to be species- and individual-specific. This knowledge can be used towards finding a match between the object (e.g. electronic device) and the user, based on the individual-specific microbiome deposited onto the object’s surface. The DNA fingerprinting-based methods were used to compare similarities in the structures of bacterial communities collected from the epidermis of 14 study subjects and the housings of their mobile phones. This study was based on the Polymerase Chain Reaction – Denaturing Gel Electrophoresis method. The results obtained revealed a high degree of similarity between the structure of bacterial genotypes present on the users’ epidermis and the microbiomes recovered from their mobile phones. PCR-DGGE can be used as the screening method, preceding the additional confirmatory analyses.

scholarly journals Structure of myosin filaments from relaxed Lethocerus flight muscle by cryo-EM at 6 Å resolution

2016 ◽  
Vol 2 (9) ◽  
pp. e1600058 ◽  
Author(s):  
Zhongjun Hu ◽  
Dianne W. Taylor ◽  
Michael K. Reedy ◽  
Robert J. Edwards ◽  
Kenneth A. Taylor
Keyword(s):  
Flight Muscle ◽  
Three Dimensional ◽  
Coiled Coil ◽  
Thick Filament ◽  
Coiled Coils ◽  
Muscle Physiology ◽  
Layer Arrangement ◽  
Thick Filaments ◽  
Unusual Position ◽  
Filament Structure

We describe a cryo–electron microscopy three-dimensional image reconstruction of relaxed myosin II–containing thick filaments from the flight muscle of the giant water bug Lethocerus indicus. The relaxed thick filament structure is a key element of muscle physiology because it facilitates the reextension process following contraction. Conversely, the myosin heads must disrupt their relaxed arrangement to drive contraction. Previous models predicted that Lethocerus myosin was unique in having an intermolecular head-head interaction, as opposed to the intramolecular head-head interaction observed in all other species. In contrast to the predicted model, we find an intramolecular head-head interaction, which is similar to that of other thick filaments but oriented in a distinctly different way. The arrangement of myosin’s long α-helical coiled-coil rod domain has been hypothesized as either curved layers or helical subfilaments. Our reconstruction is the first report having sufficient resolution to track the rod α helices in their native environment at resolutions ~5.5 Å, and it shows that the layer arrangement is correct for Lethocerus. Threading separate paths through the forest of myosin coiled coils are four nonmyosin peptides. We suggest that the unusual position of the heads and the rod arrangement separated by nonmyosin peptides are adaptations for mechanical signal transduction whereby applied tension disrupts the myosin heads as a component of stretch activation.

scholarly journals Dependence of thick filament structure in relaxed mammalian skeletal muscle on temperature and interfilament spacing

2021 ◽  
Vol 153 (3) ◽  
Author(s):  
Marco Caremani ◽  
Luca Fusi ◽  
Marco Linari ◽  
Massimo Reconditi ◽  
Gabriella Piazzesi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Thick Filament ◽  
Structural Basis ◽  
Mammalian Skeletal Muscle ◽  
X Ray ◽  
Physiological Temperature ◽  
Thick Filaments ◽  
Filament Structure ◽  
Intact Muscle ◽  
Resting Muscle

Contraction of skeletal muscle is regulated by structural changes in both actin-containing thin filaments and myosin-containing thick filaments, but myosin-based regulation is unlikely to be preserved after thick filament isolation, and its structural basis remains poorly characterized. Here, we describe the periodic features of the thick filament structure in situ by high-resolution small-angle x-ray diffraction and interference. We used both relaxed demembranated fibers and resting intact muscle preparations to assess whether thick filament regulation is preserved in demembranated fibers, which have been widely used for previous studies. We show that the thick filaments in both preparations exhibit two closely spaced axial periodicities, 43.1 nm and 45.5 nm, at near-physiological temperature. The shorter periodicity matches that of the myosin helix, and x-ray interference between the two arrays of myosin in the bipolar filament shows that all zones of the filament follow this periodicity. The 45.5-nm repeat has no helical component and originates from myosin layers closer to the filament midpoint associated with the titin super-repeat in that region. Cooling relaxed or resting muscle, which partially mimics the effects of calcium activation on thick filament structure, disrupts the helical order of the myosin motors, and they move out from the filament backbone. Compression of the filament lattice of demembranated fibers by 5% Dextran, which restores interfilament spacing to that in intact muscle, stabilizes the higher-temperature structure. The axial periodicity of the filament backbone increases on cooling, but in lattice-compressed fibers the periodicity of the myosin heads does not follow the extension of the backbone. Thick filament structure in lattice-compressed demembranated fibers at near-physiological temperature is similar to that in intact resting muscle, suggesting that the native structure of the thick filament is largely preserved after demembranation in these conditions, although not in the conditions used for most previous studies with this preparation.

scholarly journals Distinct contributions of the thin and thick filaments to length-dependent activation in heart muscle

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Xuemeng Zhang ◽  
Thomas Kampourakis ◽  
Ziqian Yan ◽  
Ivanka Sevrieva ◽  
Malcolm Irving ◽  
...  
Keyword(s):  
Heart Muscle ◽  
Structural Changes ◽  
Muscle Cells ◽  
Thick Filament ◽  
Calcium Sensitivity ◽  
Cellular Level ◽  
Thin Filaments ◽  
Thick Filaments ◽  
Filament Structure ◽  
Heart Muscle Cells

The Frank-Starling relation is a fundamental auto-regulatory property of the heart that ensures the volume of blood ejected in each heartbeat is matched to the extent of venous filling. At the cellular level, heart muscle cells generate higher force when stretched, but despite intense efforts the underlying molecular mechanism remains unknown. We applied a fluorescence-based method, which reports structural changes separately in the thick and thin filaments of rat cardiac muscle, to elucidate that mechanism. The distinct structural changes of troponin C in the thin filaments and myosin regulatory light chain in the thick filaments allowed us to identify two aspects of the Frank-Starling relation. Our results show that the enhanced force observed when heart muscle cells are maximally activated by calcium is due to a change in thick filament structure, but the increase in calcium sensitivity at lower calcium levels is due to a change in thin filament structure.

scholarly journals Myosin and paramyosin are organized about a newly identified core structure.

1985 ◽  
Vol 100 (3) ◽  
pp. 904-915 ◽  
Author(s):  
H F Epstein ◽  
D M Miller ◽  
I Ortiz ◽  
G C Berliner
Keyword(s):  
Thick Filament ◽  
Core Structure ◽  
Polar Regions ◽  
Myosin Isoforms ◽  
The Core ◽  
Filament Assembly ◽  
Thick Filaments ◽  
Filament Structure ◽  
Intermediate Domain

Myosin isoforms A and B are differentially localized to the central and polar regions, respectively, of thick filaments in body wall muscle cells of Caenorhabditis elegans (Miller, D. M. III, I. Ortiz, G. C. Berliner, and H. F. Epstein, 1983, Cell, 34:477-490). Biochemical and electron microscope studies of KCl-dissociated filaments show that the myosin isoforms occupy a surface domain, paramyosin constitutes an intermediate domain, and a newly identified core structure exists. The diameters of the thick filaments vary significantly from 33.4 nm centrally to 14.0 nm near the ends. The latter value is comparable to the 15.2 nm diameter of the core structures. The internal density of the filament core appears solid medially and hollow at the poles. The differentiation of thick filament structure into supramolecular domains possessing specific substructures of characteristic stabilities suggests a sequential mode for thick filament assembly. In this model, the two myosin isoforms have distinct roles in assembly. The behavior of the myosins, including nucleation of assembly and determination of filament length, depend upon paramyosin and the core structure as well as their intrinsic molecular properties.

scholarly journals The study of similarities among Czech alfalfa (Medicago sativa L.) varieties

2014 ◽  
Vol 62 (5) ◽  
pp. 971-977 ◽  
Author(s):  
Daniela Knotová ◽  
Jiří Skládanka ◽  
Jan Pelikán
Keyword(s):  
Dry Matter ◽  
Intraspecific Variability ◽  
Terminal Leaflet ◽  
Individual Trait ◽  
Green Matter ◽  
Medicago Sativa L ◽  
The Individual ◽  
High Degree ◽  
Degree Of Similarity ◽  
Better Than

Within the period of 2010–2011, a set of 14 Czech alfalfa cultivars was evaluated in the research locality Troubsko. On small plots and also in the individual plantations altogether 51 descriptors were evaluated. Statistical differences existing among cultivars in individual trait sunder study were analysed using the method of point and interval estimations of average values. Intraspecific variability was studied on the base of estimation of variation coefficients. A high degree of intraspecific uniformity was found in cultivars ‘Jarka’ and ‘Holyna’ while the lowest one was registered in the cultivar ‘Litava’. Green matter yields ranged from 66.3 t.ha−1 (‘Jitka’) to 77.2 t.ha−1 (‘Holyna’), hay yields from 11.71 t.ha−1 (‘Jitka’) to 15.43 t.ha−1 (‘Jarka’), and yields of seed from 0.19 t.ha−1 (‘Jitka’) to 0.35 t.ha−1 (‘Kamila’). As far as the descriptor “Alfalfa tuft dry matter” was concerned, cultivars ‘Oslava’ and ‘Holyna’ were statistically highly significantly (P < 0.01) better than than cultivars ‘Jitka’ and ‘Vlasta’. As far as the descriptor “Width of the terminal leaflet” was concerned, the cultivar ‘Palava’ was statistically highly significantly better (P < 0.01) than cultivars ‘Vlasta’, ‘Litava’, and ‘Denisa’. The existence of similarity of cultivars under study was determined by means of cluster analysis. It was found out that the highest degree of similarity existed between cultivars ‘Morava’ and ‘Niva’.

scholarly journals The positional stability of thick filaments in activated skeletal muscle depends on sarcomere length: evidence for the role of titin filaments.

1987 ◽  
Vol 105 (5) ◽  
pp. 2217-2223 ◽  
Author(s):  
R Horowits ◽  
R J Podolsky
Keyword(s):  
Sarcomere Length ◽  
Psoas Muscle ◽  
Maximum Level ◽  
Central Position ◽  
Thin Filaments ◽  
Rabbit Psoas ◽  
Thick Filaments ◽  
Final Length ◽  
The Individual ◽  
Almost All

Electron microscopy was used to study the positional stability of thick filaments in isometrically contracting skinned rabbit psoas muscle as a function of sarcomere length at 7 degrees C. After calcium activation at a sarcomere length of 2.6 micron, where resting stiffness is low, sarcomeres become nonuniform in length. The dispersion in sarcomere length is complete by the time maximum tension is reached. A-bands generally move from their central position and continue moving toward one of the Z-discs after tension has reached a plateau at its maximum level. The lengths of the thick and thin filaments remain constant during this movement. The extent of A-band movement during contraction depends on the final length of the individual sarcomere. After prolonged activation, all sarcomeres between 1.9 and 2.5 micron long exhibit A-bands that are adjacent to a Z-disc, with no intervening I-band. Sarcomeres 2.6 or 2.7 micron long exhibit a partial movement of A-bands. At longer sarcomere lengths, where the resting stiffness exceeds the slope of the active tension-length relation, the A-bands remain perfectly centered during contraction. Sarcomere symmetry and length uniformity are restored upon relaxation. These results indicate that the central position of the thick filaments in the resting sarcomere becomes unstable upon activation. In addition, they provide evidence that the elastic titin filaments, which join thick filaments to Z-discs, produce almost all of the resting tension in skinned rabbit psoas fibers and act to resist the movement of thick filaments away from the center of the sarcomere during contraction.

Distribution of c-protein isoforms in sarcomeres of developing chick skeletal muscle

1988 ◽  
Vol 46 ◽  
pp. 226-227
Author(s):  
D. A. Fischman ◽  
J. E. Dennis ◽  
T. Obinata ◽  
H. Takano-Ohmuro
Keyword(s):  
Skeletal Muscles ◽  
Thick Filament ◽  
Protein Isoforms ◽  
Actin Binding ◽  
Striated Muscles ◽  
C Protein ◽  
Sarcomeric Protein ◽  
Thick Filaments ◽  
Cross Bridges ◽  
Bridge Bearing

C-protein is a 150 kDa protein found within the A bands of all vertebrate cross-striated muscles. By immunoelectron microscopy, it has been demonstrated that C-protein is distributed along a series of 7-9 transverse stripes in the medial, cross-bridge bearing zone of each A band. This zone is now termed the C-zone of the sarcomere. Interest in this protein has been sparked by its striking distribution in the sarcomere: the transverse repeat between C-protein stripes is 43 nm, almost exactly 3 times the 14.3 nm axial repeat of myosin cross-bridges along the thick filaments. The precise packing of C-protein in the thick filament is still unknown. It is the only sarcomeric protein which binds to both myosin and actin, and the actin-binding is Ca-sensitive. In cardiac and slow, but not fast, skeletal muscles C-protein is phosphorylated. Amino acid composition suggests a protein of little or no αhelical content. Variant forms (isoforms) of C-protein have been identified in cardiac, slow and embryonic muscles.

Semiology of the Pain Syndrome - Identifying the Ideal Methods of Locoregional Anesthesia Based on Their Rationale and Features

2017 ◽  
Vol 68 (10) ◽  
pp. 2373-2377
Author(s):  
Mihaela Monica Scutariu ◽  
Vlad Danila ◽  
Corina Ciupilan ◽  
Oana Elena Ciurcanu
Keyword(s):  
Maxillofacial Surgery ◽  
Essential Element ◽  
Pain Syndrome ◽  
Oral And Maxillofacial Surgery ◽  
Structuring Element ◽  
Technical Accuracy ◽  
Locoregional Anesthesia ◽  
Special Approach ◽  
The Individual ◽  
High Degree

Anesthesia and the degree of control over the perception of pain depends on the personality of the individual, the socio-economic conditions, potential previous painful experiences and, last but not least, on fatigue and fear of the dentist. The perception of pain in patients is closely connected to their mental state. Pain is defined as a sensation of discomfort, with wide variations, both in quality and intensity, for different people in seemingly identical conditions; an unpleasant sensitive and emotional phenomena connected to the threat of a wound or caused in the tissues or described in the terms of this disease. The essential element of any type of anesthesia is analgesia, an effect which in some cases cannot be achived, due to the patient�s particularities or the physician�s lack of experience in anesthesia. Locoregional anesthesia (LRA) represents the blocking of the nociceptive sensitive and sympathetic autonomic afferents as well as that of motor efferents at the level of peripheral nerves� axons, by means of local anesthetic. To achieve the set purpose, we carried out a study on a representative human sample comprised of 10.123 patients treated in the Oral and Maxillofacial Surgery Clinic (Ambulatory) from the County Clinic Emergency Hospital St. Spiridon Iasi, between 01.01.2015-31.12.2016. The reason for the exclusion of certain categories of patients in the reseach was: the patients with a special conditions background require individual pre-anesthesia schemes, personalised for the nature of the pre-existing general condition, which must be further approved by the attending specialist physician : cardiologist, internist, diabetologist; children under 18 years old, with a high degree of anxiety; a high precentage of elderly patients, over 60 years old, possess a combination of general issues, thus requiring a special approach. The thoroughness lying at the core of the anesthetic practice, most especially the safegurading of a technical accuracy in the performance of anesthesia [12,], instead of improvisations, the lack of anatomical and stomatological training in general and the resulting inefficiency as such, is the underlying in-depth structuring element of this paper.

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