During Drosophila gastrulation, two waves of constriction occur in the apical ventral cells, leading to mesoderm invagination. The first constriction wave is a stochastic process mediated by the constriction of 40% of randomly positioned mesodermal cells and is controlled by the transcription factor Snail. The second constriction wave immediately follows and involves the other 60% of the mesode...

The midbrain-hindbrain boundary (MHB) is a highly conserved fold in the vertebrate embryonic brain. We have termed the deepest point of this fold the MHB constriction (MHBC) and have begun to define the mechanisms by which it develops. In the zebrafish, the MHBC is formed soon after neural tube closure, concomitant with inflation of the brain ventricles. The MHBC is unusual, as it forms by bend...

During epithelial tube morphogenesis, linear arrays of cells are converted into tubular structures through actomyosin-generated intracellular forces that induce tissue invagination and lumen formation. We have investigated lumen morphogenesis in the C. elegans vulva. The first discernible event initiating lumen formation is the apical constriction of the two innermost primary cells (VulF). The ...

AIM To compare ex vivo the accuracy of two impedance quotient apex locators with different scales and frequencies of the measuring circuit. METHODOLOGY In each root of 193 extracted human teeth, electronic working length determination (ELD) was carried out with a newly constructed measuring unit. In all cases, ELD was performed using the apex locators Justy II (Hager & Werken, Duisburg, Germa...

intracellular components have been identified in both invertebrate and vertebrate, extracellular regulation that allows the morphogenesis cell mass maintaining the epithelial integrity is largely unknown. Here, we present Nectin2, a cell adhesion molecule belonging to the immunoglobulin family has an essential role in the apical constriction. Nectin2 expression is spatially and temporally regul...

Apical constriction is a change in cell shape that drives key morphogenetic events including gastrulation and neural tube formation. Apical force-producing actomyosin networks drive apical constriction by contracting while connected to cell-cell junctions. The mechanisms by which developmental patterning regulates these actomyosin networks and associated junctions with spatial precision are not...

The efficacy of tactile detection of the apical constriction in flared and nonflared root canals was examined in 120 root canals of adult patients. In 68 nonflared (group 1) root canals, a #15 or #20 K-file was used to detect ("feel") the apical constriction. In 52 teeth (group 2), Hedstrom files, Gates Gliden drills #2 to #4, and ultrasonic files were used to enlarge the canal orifice and flar...

Coordination of apical constriction in epithelial sheets is a fundamental process during embryogenesis. Here, we show that DRhoGEF2 is a key regulator of apical pulsation and constriction of amnioserosal cells during Drosophila dorsal closure. Amnioserosal cells mutant for DRhoGEF2 exhibit a consistent decrease in amnioserosa pulsations whereas overexpression of DRhoGEF2 in this tissue leads to...

intracellular components have been identified in both invertebrate and vertebrate, extracellular regulation that allows the morphogenesis cell mass maintaining the epithelial integrity is largely unknown. Here, we present Nectin2, a cell adhesion molecule belonging to the immunoglobulin family has an essential role in the apical constriction. Nectin2 expression is spatially and temporally regul...

Pulpal and periradicular pathology is the common sequel following trauma to teeth severe enough cause displacement of tooth resulting in necrosis pulp as a result severing neurovascular supply near apical constriction. This case report evidenced conservative non-surgical endodontic management large periapical lesion 19-year-old young male induced due traumatic injury face.