scholarly journals MECHANISM OF STARFISH SPAWNING. IV. TENSION GENERATION IN THE OVARIAN WALL BY 1-METHYLADENINE AT THE TIME OF SPAWNING

1981 ◽  
Vol 161 (1) ◽  
pp. 172-179 ◽  
Author(s):  
HIROKO SHIRAI ◽  
YASUAKI YOSHIMOTO ◽  
HARUO KANATANI
Keyword(s):  
Ovarian Wall ◽  
Tension Generation

scholarly journals The Bdkrb2 gene family provides a novel view of viviparity adaptation in Sebastes schlegelii

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jingjing Niu ◽  
Weihao Song ◽  
Rui Li ◽  
Haiyang Yu ◽  
Jian Guan ◽  
...  
Keyword(s):  
Protein Structure ◽  
Vascular System ◽  
Critical Role ◽  
Future Research ◽  
Breeding Cycle ◽  
Exterior Surface ◽  
Black Rockfish ◽  
Vascular Regulation ◽  
Sebastes Schlegelii ◽  
Ovarian Wall

Abstract Background Black rockfish (Sebastes schlegelii) is a viviparous teleost. We proposed that the rockfish ovarian wall had a similar function to the uterus of mammals previously. In the present study, the well-developed vascular system was observed in the ovarian wall and the exterior surface of the egg membrane. In gestation, adaptation of the ovary vasculature to the rising needs of the embryos occurs through both vasodilation and neovascularization. Bdkrb2, encoding a receptor for bradykinin, plays a critical role in the control of vasodilatation by regulating nitric oxide production. Results Eight Bdkrb2 genes were identified in the black rockfish genome. These genes were located on chromosome 14, which are arranged in a tandem array, forming a gene cluster spanning 50 kb. Protein structure prediction, phylogenetic analysis, and transcriptome analysis showed that eight Bdkrb2 genes evolved two kinds of protein structure and three types of tissue expression pattern. Overexpression of two Bdkrb2 genes in zebrafish indicated a role of them in blood vessel formation or remodeling, which is an important procedure for the viviparous rockfish getting prepared for fertilization and embryos implantation. Conclusions Our study characterizes eight Bdrkb2 genes in the black rockfish, which may contribute to preparation for fertilization and embryo implantation. This research provides a novel view of viviparity adaptation and lays the groundwork for future research into vascular regulation of ovarian tissue in the breeding cycle in black rockfish.

scholarly journals Mechanical plasticity of collagen directs branch elongation in human mammary gland organoids

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
B. Buchmann ◽  
L. K. Engelbrecht ◽  
P. Fernandez ◽  
F. P. Hutterer ◽  
M. K. Raich ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Developmental Process ◽  
Branching Morphogenesis ◽  
Collagen Network ◽  
Mechanical Tension ◽  
Structural Reorganization ◽  
Linear Response Regime ◽  
Human Mammary Gland ◽  
The Matrix ◽  
Tension Generation

AbstractEpithelial branch elongation is a central developmental process during branching morphogenesis in diverse organs. This fundamental growth process into large arborized epithelial networks is accompanied by structural reorganization of the surrounding extracellular matrix (ECM), well beyond its mechanical linear response regime. Here, we report that epithelial ductal elongation within human mammary organoid branches relies on the non-linear and plastic mechanical response of the surrounding collagen. Specifically, we demonstrate that collective back-and-forth motion of cells within the branches generates tension that is strong enough to induce a plastic reorganization of the surrounding collagen network which results in the formation of mechanically stable collagen cages. Such matrix encasing in turn directs further tension generation, branch outgrowth and plastic deformation of the matrix. The identified mechanical tension equilibrium sets a framework to understand how mechanical cues can direct ductal branch elongation.

scholarly journals Cytoplasmic Dynein: Tension Generation on Microtubules and the Nucleus

2012 ◽  
Vol 6 (1) ◽  
pp. 74-81 ◽  
Author(s):  
Nandini Shekhar ◽  
Jun Wu ◽  
Richard B. Dickinson ◽  
Tanmay P. Lele
Keyword(s):  
Cytoplasmic Dynein ◽  
Tension Generation

Tension generation by actomyosin thread from a non-muscle system

Nature ◽  
1980 ◽  
Vol 285 (5761) ◽  
pp. 169-171 ◽  
Author(s):  
Fumio Matsumura ◽  
Yasuaki Yoshimoto ◽  
Noburô Kamiya
Keyword(s):  
Muscle System ◽  
Tension Generation

scholarly journals Effects of Ovarian Extract on the Growth of Ovarian Wall Cells from Kuruma Prawn

1997 ◽  
Vol 63 (6) ◽  
pp. 1042-1043
Author(s):  
Isao Yano ◽  
Hiroki Yotsuhashi
Keyword(s):  
Ovarian Wall

scholarly journals Prolonged cross-bridge binding triggers muscle dysfunction in a Drosophila model of myosin-based hypertrophic cardiomyopathy

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
William A Kronert ◽  
Kaylyn M Bell ◽  
Meera C Viswanathan ◽  
Girish C Melkani ◽  
Adriana S Trujillo ◽  
...  
Keyword(s):  
Hypertrophic Cardiomyopathy ◽  
Flight Muscle ◽  
Isometric Force ◽  
Muscle Mechanics ◽  
Muscle Dysfunction ◽  
Cardiac Myosin ◽  
Cross Bridge ◽  
Drosophila Model ◽  
Mechanistic Basis ◽  
Tension Generation

K146N is a dominant mutation in human β-cardiac myosin heavy chain, which causes hypertrophic cardiomyopathy. We examined how Drosophila muscle responds to this mutation and integratively analyzed the biochemical, physiological and mechanical foundations of the disease. ATPase assays, actin motility, and indirect flight muscle mechanics suggest at least two rate constants of the cross-bridge cycle are altered by the mutation: increased myosin attachment to actin and decreased detachment, yielding prolonged binding. This increases isometric force generation, but also resistive force and work absorption during cyclical contractions, resulting in decreased work, power output, flight ability and degeneration of flight muscle sarcomere morphology. Consistent with prolonged cross-bridge binding serving as the mechanistic basis of the disease and with human phenotypes, 146N/+ hearts are hypercontractile with increased tension generation periods, decreased diastolic/systolic diameters and myofibrillar disarray. This suggests that screening mutated Drosophila hearts could rapidly identify hypertrophic cardiomyopathy alleles and treatments.

Comparative morpho-anatomical studies of the female gonoduct within the Pratylenchidae (Nematoda: Tylenchina)

Nematology ◽  
2003 ◽  
Vol 5 (2) ◽  
pp. 293-306 ◽  
Author(s):  
Gaëtan Borgonie ◽  
Wim Bert ◽  
Ruben Van Gansbeke ◽  
Etienne Geraert ◽  
Myriam Claeys
Keyword(s):  
Electron Microscopy ◽  
Germ Cells ◽  
The Other ◽  
Radopholus Similis ◽  
Cell Extension ◽  
Anatomical Studies ◽  
Transmission Electron ◽  
Wall Cell ◽  
Ovarian Wall ◽  
Nacobbus Aberrans

AbstractThe cellular morphology of the gonoduct of six Pratylenchus species, three Pratylenchoides species, Radopholus similis, Zygotylenchus guevarai, Hirschmanniella loofi and Nacobbus aberrans was revealed by dissection and light microscopy. Except for Nacobbus aberrans, all studied species show an overall similarity in gonoduct construction, i.e., an ovary often ending with a ring of cells, an oviduct formed from two rows of four cells and a 12-celled spermatheca followed by a tricolumella containing 16-24 cells. Pratylenchoides magnicauda and Z. guevarai did not diverge from the other Pratylenchidae in this respect, although their gonoduct differs from that of Amplimerlinius and Meloidogyne, both formerly postulated as related genera. The spermatheca structure observed in N. aberrans has not been reported elsewhere in the Nematoda, although the uterus is similar to that reported within the Heteroderinae and Meloidogyninae and the uterus comprises more than 300 cells, enlarging from a tricolumella to a polycolumella. Transmission electron microscopy of Z. guevarai revealed details of the cytoplasmatic contact between epithelial cells and the germ cells; a finger-like ovarian wall cell extension was found penetrating the oocyte. The oviduct lacks a preformed lumen and comprises eight cells with highly plicated cell membranes. The spermatheca is constructed from flattened wall cells and is followed by columnar uterus cells where evidence of eggshell formation was demonstrated.

Mechanical properties of human bronchial smooth muscle in vitro

1992 ◽  
Vol 73 (4) ◽  
pp. 1481-1485 ◽  
Author(s):  
K. Ishida ◽  
P. D. Pare ◽  
J. Hards ◽  
R. R. Schellenberg
Keyword(s):  
Mechanical Properties ◽  
Smooth Muscle ◽  
Electrical Field Stimulation ◽  
Tracheal Smooth Muscle ◽  
Cross Sectional ◽  
Velocity Of Shortening ◽  
Muscle Shortening ◽  
Tension Generation ◽  
Very High

The in vitro mechanical properties of smooth muscle strips from 10 human main stem bronchi obtained immediately after pneumonectomy were evaluated. Maximal active isometric and isotonic responses were obtained at varying lengths by use of electrical field stimulation (EFS). At the length (Lmax) producing maximal force (Pmax), resting tension was very high (60.0 +/- 8.8% Pmax). Maximal fractional muscle shortening was 25.0 +/- 9.0% at a length of 75% Lmax, whereas less shortening occurred at Lmax (12.2 +/- 2.7%). The addition of increasing elastic loads produced an exponential decrease in the shortening and velocity of shortening but increased tension generation of muscle strips stimulated by EFS. Morphometric analysis revealed that muscle accounted for 8.7 +/- 1.5% of the total cross-sectional tissue area. Evaluation of two human tracheal smooth muscle preparations revealed mechanics similar to the bronchial preparations. Passive tension at Lmax was 10-fold greater and maximal active shortening was threefold less than that previously demonstrated for porcine trachealis by us of the same apparatus. We attribute the limited shortening of human bronchial and tracheal smooth muscle to the larger load presumably provided by a connective tissue parallel elastic component within the evaluated tissues, which must be overcome for shortening to occur. We suggest that a decrease in airway wall elastance could increase smooth muscle shortening, leading to excessive responses to contractile agonists, as seen in airway hyperresponsiveness.

Effect of dichloroacetate on mechanical performance and metabolism of compromised diaphragm muscle

1992 ◽  
Vol 72 (3) ◽  
pp. 1149-1155 ◽  
Author(s):  
B. P. deBoisblanc ◽  
K. Meszaros ◽  
A. Burns ◽  
G. J. Bagby ◽  
S. Nelson ◽  
...  
Keyword(s):  
Glucose Oxidation ◽  
Mechanical Performance ◽  
Lactate Production ◽  
Diaphragm Muscle ◽  
Tetanic Stimulation ◽  
Lactate Oxidation ◽  
Diaphragmatic Fatigue ◽  
Tension Generation

We investigated the effect of dichloroacetate (DCA) on tension generation and carbohydrate metabolism of the rat diaphragm in vitro. Isolated diaphragms were placed in individual organ chambers and were hooked to force-displacement transducers. Net lactate production and glucose and lactate oxidation were measured in vitro. Diaphragmatic fatigue was precipitated by in vivo endotoxemic shock, by in vitro hypoxia, or by in vitro repetitive tetanic stimulation. In diaphragms isolated from endotoxemic rats, DCA increased tension generation by 30 and 20% at stimulation frequencies of 20 and 100 Hz, respectively. Associated with changes in mechanical performance, DCA reduced net lactate production by 53% after 60 min of incubation and increased glucose oxidation 54% but had no effect on lactate oxidation. During in vitro hypoxia, DCA reduced net diaphragmatic lactate production by 30% and increased glucose oxidation by 45% but did not attenuate hypoxic fatigue. DCA had no effect on tension generation during repetitive tetanic stimulation. We conclude that DCA improves in vitro diaphragmatic fatigue due to endotoxicosis but not due to hypoxia or repetitive stimulation.

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