Search results for "morphogenesis"
showing 10 items of 178 documents
Biogenesis of the Fungal Cell Wall
1994
Cell walls play essential roles in growth, development, and in interactions of fungi with the environment and with other cells. Besides its primary protective role in shielding the cell against osmotic, chemical, and biological harm, the wall is involved in many other functions including morphogenesis, and some activities that may be denominated as “social”, such as morphological responses, antigenic expression, adhesion, and cell-cell interaction (Peberdy 1990; Ruiz-Herrera 1992; Sentandreu et al. 1991). There are many data supporting the idea that temporal and spatial regulation of wall polymer synthesis and assembly are critical for the properties of the walls, which thus do not exclusiv…
Effect of magnetic fields on seedling growth and cyto-morphogenesis inSinapis albaL.
2001
Abstract The magnetic treatment presented in this study could be included among cultivation procedures aimed at a better utilisation of plant species. The treatment enhances seedling growth (expressed in fresh weight or in length of the hypocotyl) stimulates morphogenic events (premature differentiation of the reticulate xylem elements, increased wall thickness, reduction of the xylem diameter, increase of acid phosphatases) and renders the seedling batches more homogeneous. Our study demonstrates that exposure to weak (30 mT) magnetic fields for short periods (15, 30, 60 seconds) stimulates seedling growth.
Induction of identified mesodermal cells by CNS midline progenitors in Drosophila.
1997
ABSTRACT The Drosophila ventral midline cells generate a discrete set of CNS lineages, required for proper patterning of the ventral ectoderm. Here we provide the first evidence that the CNS midline cells also exert inductive effects on the mesoderm. Mesodermal progenitors adjacent to the midline progenitor cells give rise to ventral somatic mucles and a pair of unique cells that come to lie dorsomedially on top of the ventral nerve cord, the so-called DM cells. Cell ablation as well as cell transplantation experiments indicate that formation of the DM cells is induced by midline progenitors in the early embryo. These results are corroborated by genetic analyses. Mutant single minded embryo…
A common precursor for glia and neurons in the embryonic CNS of Drosophila gives rise to segment-specific lineage variants
1993
ABSTRACT The nervous system consists of two classes of cells, neurons and glia, which differ in morphology and function. They derive from precursors located in the neurogenic region of the ectoderm. In this study, we present the complete embryonic lineage of a neuroectodermal precursor in Drosophila that gives rise to neurons as well as glia in the abdominal CNS. This lineage is conserved among different Drosophila species. We show that neuronal and glial cell types in this clone derive from one segregating precursor, previously described as NB1-1. Thus, in addition to neuroblasts and glioblasts, there exists a third class of CNS precursors in Drosophila, which we call neuroglioblasts. We f…
The fate of the CNS midline progenitors in Drosophila as revealed by a new method for single cell labelling
1994
ABSTRACT We present a new method for marking single cells and tracing their development through embryogenesis. Cells are labelled with a lipophilic fluorescent tracer (DiI) in their normal positions without impaling their membranes. The dye does not diffuse between cells but is transferred to the progeny, disclosing their morphology in all detail. Behaviour of labelled cells can be observed in vivo (cell divisions, morphogenetic movements and differentiation). Following photoconversion of the dye, fully differentiated clones can be analyzed in permanent preparations. We apply this method for cell lineage analysis of the embryonic Drosophila CNS. Here we describe the fate of the CNS midline …
Two Enhancers Control Transcription of Drosophila muscleblind in the Embryonic Somatic Musculature and in the Central Nervous System
2014
The phylogenetically conserved family of Muscleblind proteins are RNA-binding factors involved in a variety of gene expression processes including alternative splicing regulation, RNA stability and subcellular localization, and miRNA biogenesis, which typically contribute to cell-type specific differentiation. In humans, sequestration of Muscleblind-like proteins MBNL1 and MBNL2 has been implicated in degenerative disorders, particularly expansion diseases such as myotonic dystrophy type 1 and 2. Drosophila muscleblind was previously shown to be expressed in embryonic somatic and visceral muscle subtypes, and in the central nervous system, and to depend on Mef2 for transcriptional activatio…
The angiopoietin-Tie2 pathway regulates Purkinje cell dendritic morphogenesis in a cell-autonomous manner.
2021
Neuro-vascular communication is essential to synchronize central nervous system development. Here, we identify angiopoietin/Tie2 as a neuro-vascular signaling axis involved in regulating dendritic morphogenesis of Purkinje cells (PCs). We show that in the developing cerebellum Tie2 expression is not restricted to blood vessels, but it is also present in PCs. Its ligands angiopoietin-1 (Ang1) and angiopoietin-2 (Ang2) are expressed in neural cells and endothelial cells (ECs), respectively. PC-specific deletion of Tie2 results in reduced dendritic arborization, which is recapitulated in neural-specific Ang1-knockout and Ang2 full-knockout mice. Mechanistically, RNA sequencing reveals that Tie…
The Chemokine Networks in Sponges: Potential Roles in Morphogenesis, Immunity and Stem Cell Formation
2003
Porifera (sponges) are now well accepted as the phylum which branched off first from the common ancestor of all metazoans, the Urmetazoa. The transition to the Metazoa became possible because during this phase, cell-cell as well as cell-matrix adhesion molecules evolved which allowed the formation of a colonial stage of animals. The next prerequisite for the evolution to the Urmetazoa was the establishment of an effective immune system which, flanked by apoptosis, allowed the formation of a first level of individuation.
Chreod.
2020
The concept of chreod was introduced in 1957 by the English theoretical biologist Conrad Hal Waddington (cf. Waddington: 1957; Galperin: 2008). From a linguistic point of view, the word “chreod” is a neologism, or, more precisely, a compound formed by the combination of two Greek words: the verb chre- (“it is necessary, must”) and the substantive -hodos (“way, road”). Therefore, it means literally “obliged pathway” (cf. Fabris 2018: 252, n. 6). Of course, such an etymology covers only a little bit of the semantic repertoire deployed by chreod. But, it is however true that some aspects of the biology of living systems can be described in these terms. Indeed, at the most general level, the id…