169,807 research outputs found
Spectrin and ankyrin-like proteins in the egg of Discoglossus pictus (Anura): identification and localization in the site of sperm entrance versus the rest of the egg
No full text25), C.. Dev. Growth and Diff. 35: 161-171
Different cytoskeletal organization in two maturation stages of Discoglossus pictus (Anura) oocytes: thickness and stability of actin microfilaments and tropomyosin immunolocalization.
No full textIn Discoglossus pictus oocytes, the germinative area (GA) contains long and irregular microvilli where actin microfilaments are located. In the egg, the funnel-shaped dimple that originates by invagination of the GA is present. In the dimple both microvilli and microfilament bundles have a very orderly appearance. This report extends previous observations (Campanella and Gabbiani, Gamete Res 3:99-114, 1980) and shows that GA microfilaments are thinner (36 A average) than dimple microfilaments (60 A average), as measured in ultrathin section. Moreover, the interfilament distance is smaller in GA bundles than in the dimple bundles. To get an insight into actin organization in oocytes and eggs, we used an actin-depolymerizing factor (ADF) in which cryostat sections were incubated prior to immunofluorescent staining with antiactin antibodies. The microfilaments of the GA microvilli and partially of the oocyte cortex are resistant to ADF when compared to those in the dimple and the rest of the egg cortex. We also investigated immunocytochemically the presence of tropomyosin and found that this protein is localized in the dimple and in the cortex of oocytes and eggs but is absent in the GA
DIFFERENTIAL-EFFECTS OF GELSOLINS ON TISSUE-CULTURE CELLS
No full textHUCKRIEDE A, FUCHTBAUER A, Hinssen H, CHAPONNIER C, WEEDS A, JOCKUSCH BM. DIFFERENTIAL-EFFECTS OF GELSOLINS ON TISSUE-CULTURE CELLS. CELL MOTILITY AND THE CYTOSKELETON. 1990;16(4):229-238
Una isoforma di actina è importante per la formazione del blastema rigenerativo di planaria
No full textSpectrin and ankyrin-like proteins in the egg of Discoglossus pictus (Anura): identification and localization in the site of sperm entrance versus the rest of the egg
No full text25), C.. Dev. Growth and Diff. 35: 161-171
Correlation of {alpha}-skeletal actin expression, ventricular fibrosis and heart function with the degree of pressure overload cardiac hypertrophy in rats
No full textWe have analysed alterations of alpha-skeletal actin expression and volume fraction of fibrosis in the ventricular myocardium and their functional counterpart in terms of arrhythmogenesis and haemodynamic variables, in rats with different degrees of compensated cardiac hypertrophy induced by infra-renal abdominal aortic coarctation. The following coarctation calibres were used: 1.3 (AC1.3 group), 0.7 (AC0.7) and 0.4 mm (AC0.4); age-matched rats were used as controls (C group). One month after surgery, spontaneous and sympathetic-induced ventricular arrhythmias were telemetrically recorded from conscious freely moving animals, and invasive haemodynamic measurements were performed in anaesthetized animals. After killing, subgroups of AC and C rats were used to evaluate in the left ventricle the expression and spatial distribution of alpha-skeletal actin and the amount of perivascular and interstitial fibrosis. As compared with C, all AC groups exhibited higher values of systolic pressure, ventricular weight and ventricular wall thickness. AC0.7 and AC0.4 rats also showed a larger amount of fibrosis and upregulation of alpha-skeletal actin expression associated with a higher vulnerability to ventricular arrhythmias (AC0.7 and AC0.4) and enhanced myocardial contractility (AC0.4). Our results illustrate the progressive changes in the extracellular matrix features accompanying early ventricular remodelling in response to different degrees of pressure overload that may be involved in the development of cardiac electrical instability. We also demonstrate for the first time a linear correlation between an increase in alpha-skeletal actin expression and the degree of compensated cardiac hypertrophy, possibly acting as an early compensatory mechanism to maintain normal mechanical performance
Alpha actin isoforms expression in human and rat adult cardiac conduction system
No full textIn the adult heart, cardiac muscle comprises the working myocardium and the conduction system (CS). The latter includes the sinoatrial node (SAN), the internodal tract or bundle (IB), the atrioventricular node (AVN), the atrioventricular bundle (AVB), the bundle branches (BB) and the peripheral Purkinje fibers (PF). Most of the information concerning the phenotypic features of CS tissue derives from the characterization of avian and rodent developing hearts; data concerning the expression of actin isoforms in adult CS cardiomyocytes are scarce. Using specific antibodies, we investigated the distribution of alpha-skeletal (alpha-SKA), alpha-cardiac (alpha-CA), alpha-smooth muscle (alpha-SMA) actin isoforms and other muscle-typical proteins in the CS of human and rat hearts at different ages. SAN and IB cardiomyocytes were characterized by the presence of alpha-SMA, alpha-CA, calponin and caldesmon, whereas alpha-SKA and vimentin were absent. Double immunofluorescence demonstrated the co-localisation of alpha-SMA and alpha-CA in I-bands of SAN cardiomyocytes. AVN, AVB, BB and PF cardiomyocytes were alpha-SMA, calponin, caldesmon and vimentin negative, and alpha-CA and alpha-SKA positive. No substantial differences in actin isoform distribution were observed in human and rat hearts, except for the presence of isolated subendocardial alpha-SMA positive cardiomyocytes co-expressing alpha-CA in the ventricular septum of the rat. Aging did not influence CS cardiomyocyte actin isoform expression profile. These findings support the concept that cardiomyocytes of SAN retain the phenotype of a developing myogenic cell throughout the entire life span
DIFFERENT CYTOSKELETAL ORGANIZATION IN TWO MATURATION STAGES OF DISCOGLOSSUS PICTUS (ANURA) OOCYTES: THICKNESS AND STABILITY OF ACTIN MICROFILAMENTS AND TROPOMYOSIN IMMUNOLOCALIZATION.
No full text
DIFFERENT CYTOSKELETAL ORGANIZATION IN TWO MATURATION STAGES OF DISCOGLOSSUS PICTUS (ANURA) OOCYTES: THICKNESS AND STABILITY OF ACTIN MICROFILAMENTS AND TROPOMYOSIN IMMUNOLOCALIZATION.
No full text- …
