Home About us Contact
|
Home About us Contact | ||
|
|
||
Wall Muscle (wall + muscle)
Selected AbstractsCaenorhabditis elegans expresses three functional profilins in a tissue-specific mannerCYTOSKELETON, Issue 1 2006D. Polet Abstract Profilins are actin binding proteins, which also interact with polyphosphoinositides and proline-rich ligands. On the basis of the genome sequence, three diverse profilin homologues (PFN) are predicted to exist in Caenorhabditis elegans. We show that all three isoforms PFN-1, PFN-2, and PFN-3 are expressed in vivo and biochemical studies indicate they bind actin and influence actin dynamics in a similar manner. In addition, they bind poly(L -proline) and phosphatidylinositol 4,5-bisphosphate micelles. PFN-1 is essential whereas PFN-2 and PFN-3 are nonessential. Immunostainings revealed different expression patterns for the profilin isoforms. In embryos, PFN-1 localizes in the cytoplasm and to the cell,cell contacts at the early stages, and in the nerve ring during later stages. During late embryogenesis, expression of PFN-3 was specifically detected in body wall muscle cells. In adult worms, PFN-1 is expressed in the neurons, the vulva, and the somatic gonad, PFN-2 in the intestinal wall, the spermatheca, and the pharynx, and PFN-3 localizes in a striking dot-like fashion in body wall muscle. Thus the model organism Caenorhabditis elegans expresses three profilin isoforms and is the first invertebrate animal with tissue-specific profilin expression. Cell Motil. Cytoskeleton, 2006.© 2005 Wiley-Liss, Inc. [source] pMesogenin1 and 2 function directly downstream of Xtbx6 in Xenopus somitogenesis and myogenesisDEVELOPMENTAL DYNAMICS, Issue 12 2008Shunsuke Tazumi Abstract T-box transcription factor tbx6 and basic-helix-loop-helix transcription factor pMesogenin1 are reported to be involved in paraxial mesodermal differentiation. To clarify the relationship between these genes in Xenopus laevis, we isolated pMesogenin2, which showed high homology with pMesogenin1. Both pMesogenin1 and 2 appeared to be transcriptional activators and were induced by a hormone-inducible version of Xtbx6 without secondary protein synthesis in animal cap assays. The pMesogenin2 promoter contained three potential T-box binding sites with which Xtbx6 protein was shown to interact, and a reporter gene construct containing these sites was activated by Xtbx6. Xtbx6 knockdown reduced pMesogenin1 and 2 expressions, but not vice versa. Xtbx6 and pMesogenin1 and 2 knockdowns caused similar phenotypic abnormalities including somite malformation and ventral body wall muscle hypoplasia, suggesting that Xtbx6 is a direct regulator of pMesogenin1 and 2, which are both involved in somitogenesis and myogenesis including that of body wall muscle in Xenopus laevis. Developmental Dynamics 237:3749,3761, 2008. © 2008 Wiley-Liss, Inc. [source] Functional characterization of alternatively spliced 5-HT2 receptor isoforms from the pharynx and muscle of the parasitic nematode, Ascaris suumJOURNAL OF NEUROCHEMISTRY, Issue 2 2002Xinyan Huang Abstract Serotonin (5-HT) receptors play key regulatory roles in nematodes and alternatively spliced 5-HT2 receptor isoforms have been identified in the parasitic nematode, Ascaris suum. 5-HT2As1 and 5-HT2As2 contain different C-termini, and 5-HT2As1,4 lacks 42 amino acids at the C-terminus of the third intracellular loop. 5-HT2As1 and 5-HT2As2 exhibited identical pharmacological profiles when stably expressed in human embryonic kidney (HEK) 293 cells. Both 5-HT2As isoforms had higher affinity for 5-HT than their closely related Caenorhabditis elegans homolog (5-HT2Ce). This increased 5-HT affinity was not related to the substitution in 5-HT2As1 of F120 for Y in the highly conserved DRY motif found in the second intracellular loop of other 5-HT receptors, since a 5-HT2As1F120Y mutant actually exhibited increased 5-HT affinity compared with that of 5-HT2As1. As predicted, cells expressing either 5-HT2As1 or 5-HT2As2 exhibited a 5-HT-dependent increase in phosphatidylinositol (PI) turnover. In contrast, although 5-HT2As1,4 displayed a 10-fold higher affinity for 5-HT and 5-HT agonists than either 5-HT2As1 or 5-HT2As2, 5-HT2As1,4 did not couple to either PI turnover or adenyl cyclase activity. Based on RT,PCR, 5-HT2As1 and 5-HT2As2 were more highly expressed in pharynx and body wall muscle and 5-HT2As1,4 in nerve cord/hypodermis. This is the first report of different alternatively spliced 5-HT2 receptor isoforms from any system. [source] FLUID FLOW IN DISTENSIBLE VESSELSCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 2 2009CD Bertram SUMMARY 1Flow in single vascular conduits is reviewed, divided into distended and deflated vessels. 2In distended vessels with pulsatile flow, wave propagation and reflection dominate the spatial and temporal distribution of pressure, determining the shape, size and relative timing of measured pressure waveforms, as well as the instantaneous pressure gradient everywhere. Considerable research has been devoted to accessing the information on pathological vascular malformations contained in reflected waves. Slow waves of contraction of vessel wall muscle, responsible for transport of oesophageal, ureteral and gut contents, have also been modelled. 3The pressure gradient in a vessel drives the flow. Flow rate can be predicted both analytically and numerically, but analytical theory is limited to idealized geometry. The complex geometry of biological system conduits necessitates computation instead. Initially limited to rigid boundaries, numerical methods now include fluid,structure interaction and can simultaneously model solute transport, thus predicting accurately the environment of the mechanosensors and chemosensors at vessel surfaces. 4Deflated vessels display all phenomena found in distended vessels, but have additional unique behaviours, especially flow rate limitation and flow-induced oscillation. Flow rate limitation is widespread in the human body and has particular diagnostic importance in respiratory investigation. Because of their liquid lining, the pulmonary airways are also characterized by important two-phase flows, where surface tension phenomena create flows and determine the patency and state of collapse of conduits. 5Apart from the vital example of phonation, sustained self-excited oscillation is largely avoided in the human body. Where it occurs in snoring, it is implicated in the pathological condition of sleep apnoea. [source] Fetal development of the human gubernaculum with special reference to the fasciae and muscles around itCLINICAL ANATOMY, Issue 6 2008Hitoshi Niikura Abstract Previous descriptions of human gubernacular embryology failed to follow some basic developmental processes, and surgically relevant structures, such as the iliopubic tract, had not been discussed relative to gubernacular development. We addressed these shortcomings in this study that examined two stage-groups of human fetuses. At 8,12 weeks of gestation, the gubernaculum arose from the mesonephric fold at or near the gonad. Gubernacular mesenchyme communicated with the subcutaneous tissue via a narrow slit in the rectus aponeurosis. The inguinal fold, containing the inferior epigastric vessels, was separated from the gubernaculum. At 20,25 weeks of gestation, the gubernaculum connected to the testis or uterus. When the testis successfully descended to a peritoneal recess on the lateral side of the umbilical artery, the gubernaculum connected to the testis free of interference by the thick artery and its associated peritoneal fold. This may explain the known asymmetry in testicular descent. The inguinal canal was enclosed by a sheet-like aponeurosis: its ventromedial part was composed of the rectus sheath and the external oblique aponeurosis, whereas the dorsolateral part consisted of a thick aponeurosis covering or facing the iliopsoas. The former (latter) aponeurosis seemed to develop into the inguinal ligament (the iliopubic tract) in adults. According to the topohistology of the muscles associated with the interfoveolar ligament, we identified muscle fragments around the gubernaculum as derivatives of the transversus and/or internal oblique. Consequently, the inguinal canal contained the cremaster proper developing within the gubernaculum and parts of the abdominal wall muscles mechanically incorporated into the canal. Clin. Anat. 21:547,557, 2008. © 2008 Wiley-Liss, Inc. [source] | ||||||||||