Search results for "morphogenesis"

2014

Morphogenesis in plants is usually reconstructed by scanning electron microscopy and histology of meristematic structures. These techniques are destructive and require many samples to obtain a consecutive series of states. Unfortunately, using this methodology the absolute timing of growth and complete relative initiation of organs remain obscure. To overcome this limitation, an in vivo observational method based on Epi-Illumination Light Microscopy (ELM) was developed and tested with a male inflorescence meristem (floral unit) of the handkerchief tree Davidia involucrata Baill. (Nyssaceae). We asked whether the most basal flowers of this floral unit arise in a basipetal sequence or, altern…

A luminal glycoprotein drives dose-dependent diameter expansion of the Drosophila melanogaster hindgut tube

2012

An important step in epithelial organ development is size maturation of the organ lumen to attain correct dimensions. Here we show that the regulated expression of Tenectin (Tnc) is critical to shape the Drosophila melanogaster hindgut tube. Tnc is a secreted protein that fills the embryonic hindgut lumen during tube diameter expansion. Inside the lumen, Tnc contributes to detectable O-Glycans and forms a dense striated matrix. Loss of tnc causes a narrow hindgut tube, while Tnc over-expression drives tube dilation in a dose-dependent manner. Cellular analyses show that luminal accumulation of Tnc causes an increase in inner and outer tube diameter, and cell flattening within the tube wall,…

Hybridization, developmental stability, and functionality of morphological traits in the ground beetle Carabus solieri (Coleoptera, Carabidae).

2006

Correspondance.: stephane.garnier@u-bourgogne.fr; International audience; The assessment of developmental stability in hybrids can provide valuable information in the study of species formation because it allows an evaluation of the degree of incompatibility of genetic systems that control developmental processes. The present study assessed the impact of two hybridization events, assumed to have occurred at different times, on developmental instability in the ground beetle Carabus solieri . Developmental instability was estimated in 678 individuals from 27 populations from the fluctuating asymmetry (FA) levels of four morphological traits: the tibia length of middle and hind legs, which are…

: Quantification of the morphological evolution of the Hominid skull and heterochronies

1998

Comparisons of adult skulls of various species of great apes, fossil hominids and modem humans in the sagittal, Francfort and ortho-sagittal planes reveal a series of three separate organisation plans: 'GreatApe', 'Australopithecine'and 'Homo', tbe latter including primitive men (Homo ergaster-erectus-neandertalensis) and modern humans (Homo sapiens). Morphological changes between these plans are quantified for the first time here by vector fields. This study confirms the existence of cranio-facial contraction, which occurs as a series of leaps. The juvenile morphology of the great ape skull is broadly preserved in adult Homo sapiens, suggesting that numerous heterochronies have occurred in…

Live imaging of developmental processes in a living meristem of Davidia involucrata (Nyssaceae).

2014

Morphogenesis in plants is usually reconstructed by scanning electron microscopy and histology of meristematic structures. These techniques are destructive and require many samples to obtain a consecutive series of states. Unfortunately, using this methodology the absolute timing of growth and complete relative initiation of organs remain obscure. To overcome this limitation, an in vivo observational method based on Epi-Illumination Light Microscopy (ELM) was developed and tested with a male inflorescence meristem (floral unit) of the handkerchief tree Davidia involucrata Baill. (Nyssaceae). We asked whether the most basal flowers of this floral unit arise in a basipetal sequence or, altern…

Iron Induces Proliferation and Morphogenesis in Primmorphs from the Marine SpongeSuberites domuncula

2002

Dissociated cells from marine demosponges retain their proliferation capacity if they are allowed to form special aggregates, the primmorphs. On the basis of incorporation studies and septin gene expression, we show that Fe3+ ions are required for the proliferation of cells in primmorphs from Suberites domuncula. In parallel, Fe3+ induced the expression of ferritin and strongly stimulated the synthesis of spicules. This result is supported by the finding that the enzymatic activity of silicatein, converting organosilicon to silicic acid, depends on Fe3+. Moreover, the expression of a scavenger receptor molecule, possibly involved in the morphology of spicules, depends on the presence of Fe3…

Mechanobiological computational model for the development and formation of synovial joints

2019

El desarrollo de las articulaciones sinoviales se debe a diferentes factores genéticos, bioquímicos y mecánicos. Comienza en el brote de las extremidades, que tienen una masa ininterrumpida de células mesenquimales dentro de su núcleo, el blastema esquelético. La mayoría de estas células blastemales se diferencian en condrocitos; sin embargo, algunas de estas células permanecen, sin diferenciar, en el sitio de la futura articulación (interzona). La separación de los rudimentos ocurre con el proceso de cavitación dentro de la interzona. Después de la cavitación, se produce la morfogénesis articular y el hueso toma su forma final. Una vez finalizado el período embrionario, la articulación sin…

Human temporomandibular joint morphogenesis

2007

Temporomandibular joint morphogenesis was studied. Ranging in age of fetuses examine was from 6 to 14 weeks’ gestation. Our results showed the condyle so first element that appear between 6° and 8° week (condylar blastema). After a week appear temporal elements. Disk appear at the same time of glenoid blastema and its reaches an advanced differentiation before of the condyle and temporal element, so these don’t effect mechanical compression on mesenchimal where we find the disk. So we think that the disk result of genetic expression and it isn’t the result of mechanical compression. The inferior joint cavity appear to 12 week. The superior joint appear to 13-14 week. In conclusion, the appe…

Collective Locomotion of Human Cells, Wound Healing and Their Control by Extracts and Isolated Compounds from Marine Invertebrates

2020

The collective migration of cells is a complex integrated process that represents a common theme joining morphogenesis, tissue regeneration, and tumor biology. It is known that a remarkable amount of secondary metabolites produced by aquatic invertebrates displays active pharmacological properties against a variety of diseases. The aim of this review is to pick up selected studies that report the extraction and identification of crude extracts or isolated compounds that exert a modulatory effect on collective cell locomotion and/or skin tissue reconstitution and recapitulate the molecular, biochemical, and/or physiological aspects, where available, which are associated to the substances und…

Antibodies to cell surface ganglioside GD3 perturb inductive epithelial-mesenchymal interactions

1988

Abstract Most epithelial sheets emerge during embryogenesis by a branching and growth of the epithelium. The surrounding mesenchyme is crucial for this process. We report that branching morphogenesis and the formation of a new epithelium from the mesenchyme in the embryonic kidney can be blocked by a monoclonal antibody reacting with a surface glycolipid, disialoganglioside G D3 . In contrast, a more than 10-fold excess of antibodies to adhesive glycoproteins (N-CAM, L -CAM, fibronectin) fails to inhibit morphogenesis. Although the anti-G D3 antibody affected epithelial development, the disialoganglioside G D3 was expressed not in the epithelium, but in the mesenchyme surrounding the develo…