Search results for "Apparatu"
showing 10 items of 195 documents
The p21-activated kinase Mbt is a component of the apical protein complex in central brain neuroblasts and controls cell proliferation
2013
The final size of the central nervous system is determined by precisely controlled generation, proliferation and death of neural stem cells. We show here that the Drosophila PAK protein Mushroom bodies tiny (Mbt) is expressed in central brain progenitor cells (neuroblasts) and becomes enriched to the apical cortex of neuroblasts in a cell cycle- and Cdc42-dependent manner. Using mushroom body neuroblasts as a model system, we demonstrate that in the absence of Mbt function, neuroblasts and their progeny are correctly specified and are able to generate different neuron subclasses as in the wild type, but are impaired in their proliferation activity throughout development. In general, loss of…
The serosa of Manduca sexta (Insecta, Lepidoptera): ontogeny, secretory activity, structural changes, and functional considerations
2001
In Manduca sexta, the blastoderm forms successively and becomes immediately cellularized as the cleavage energids reach the surface of the oocyte. Presumptive serosal cells are large and contain 2 or 4 large polyploid nuclei; presumptive embryonic cells are small and mononuclear. All parts of the blastoderm participate in the uptake and digestion of yolk material. About 10 h post-oviposition, the blastoderm breaks at the amnioserosal fold and the extraembryonic part closes above the germ band and constitutes the serosa (12 h post-oviposition, i.e. 10% development completed). At once, the serosa starts to secrete a cuticle consisting of an epi- and a lamellated endocuticle. Detachment of the…
Quantitative electron microscopic observations on Paneth cells of germfree and ex-germfree Wistar rats.
1986
Ultrastructural changes of Paneth cells of germfree (Gf) rats which had been inoculated with bacteria-containing feces from conventionally-reared (SPF) rats were quantitatively examined. 12 and 24 h after inoculation, the Paneth cells showed a striking decrease in the number of secretory granules and the occurrence of large vacuoles. Phagosomes containing bacteria were not seen. After 4 days, the secretory granules reaccumulated and smooth-surfaced apical vesicles increased in number. It is discussed that the large vacuoles may be related to membrane-retrieval events following the massive extrusion of secretory granules whereas the apical vesicles appear to serve this function when exocytos…
Effects of Ga3 and Ca2+ on barley aleurone protoplasts: a freeze-fracture study
1988
Freeze-fracture electron microscopy was used to study changes in the endomembrane system of barley (Hordeum vulgare L. cv. Himalaya) aleurone protoplasts. Protoplasts were used for this study because their response to calcium and the plant hormone gibberellic acid (Ga3) can be monitored prior to rapid freezing of cells for electron microscopy. Protoplasts incubated in Ga3 plus Ca2+ secrete elevated levels of a-amylase relative to cells incubated in Ga3 or Ca2+ alone. The endoplasmic reticulum (ER) and Golgi apparatus of protoplasts incubated in Ga3 plus Ca2+ undergo changes that are well correlated with the synthesis and secretion of a-amylase. The ER, which appears as short, single sheets …
A PC-based wattmeter for high accuracy power measurements
2010
This paper proposes the use of a commercial data acquisition board (DAQ) connected to a common personal computer for high accuracy power measurements. In the paper the set up of the PC-based wattmeter is described and an experimental evaluation of its metrological performances is made by means of the comparison with a simultaneous coherent digital sampling wattmeter realized with two high-precision DMMs Hewlett Packard Model 3458 A. In both cases the power source is a Fluke 6100A/E electrical power standard. © 2010 IEEE.
L’apparato effimero allestito nella cattedrale di Palermo per le cerimonie funebri di Carlo III di Borbone (1789): storia e rappresentazione digitale
2022
The paper focus on the ephemeral apparatus realized by the architect Salvatore Attinelli on the occasion of the funeral of Charles III of Bourbon, to be set up inside the cathedral of Palermo, in those years affected by a total internal modernization based on the project commissioned in 1767 to Ferdinando Fuga. This apparatus, in an article published by the academic Giuseppina Leone in 2001, was considered an alternative project to the proposal of Ferdinando Fuga, considered expensive and with a language not responding to the rules of good and modern architecture. The purpose of this paper is to reinforce the hypothesis of an apparatus having design purposes, and to verify its feasibility t…
Radiative heat exchanges of people in complex geometry buildings: An experimentally based algorithm for computing angle factors
2008
Thermal comfort of people working or living in confined spaces depends, to a large extent, on the radiative thermal exchanges. These contributions are expressed, among other things, as a function of the mean radiant temperature that, in the general cases where there is a presence of high intensity sources, must be expressed as a function of the angle factors between subjects and the surrounding surfaces of enclosures. Angle factors, in turn, depend on the projected area factors. Despite this evidence, at the present there is a lack in the availability of simple and reliable methods capable of computing angle factors of people in assigned postures with respect to complex geometry buildings. …
The role of the hydrophobic force in bilayer adhesion and fusion
1991
The Surface Forces Apparatus technique was used for measuring the adhesion, deformation, and fusion of bilayers supported on mica. The technique allows the molecular rearrangements to be followed in real time during the fusion process, and the most important forces involved to be identified. The adhesion between two bilayers can be increased by two orders of magnitude if they are thinned so as to expose more hydrophobic groups. For all the bilayer systems studied a single basic fusion mechanism was found in which the bilayers do not “overcome” the short-range repulsive steric-hydration forces; instead, local bilayer deformations allow these repulsive forces to be “bypassed”. The results fur…
Mapping the protein composition oftrans-Golgi network (TGN)-derived carrier vesicles from polarized MDCK cells
1998
In polarized MDCK cells, proteins and lipids are sorted in the trans-Golgi network /TGN) and packaged into different vesicular carriers that are delivered to the apical or basolateral cell surface. To gain insight into the sorting and trafficking machinery, we have previously isolated TGN-derived carrier vesicles from perforated MDCK cells. The composition of immuno-isolated apical and basolateral carriers was mapped by two-dimensional (2-D) gel electrophoresis. Here we describe the identification of several components of the vesicle fraction by using three different methods. 2-D gel comigration was performed with carrier vesicles isolated from metabolically labeled MDCK cells and human epi…
The transmembrane Bax inhibitor motif (TMBIM) containing protein family: Tissue expression, intracellular localization and effects on the ER CA2+-fil…
2015
Abstract Bax inhibitor-1 (BI-1) is an evolutionarily conserved pH-dependent Ca2+ leak channel in the endoplasmic reticulum and the founding member of a family of six highly hydrophobic mammalian proteins named transmembrane BAX inhibitor motif containing (TMBIM) 1-6 with BI-1 being TMBIM6. Here we compared the structure, subcellular localization, tissue expression and the effect on the cellular Ca2+ homeostasis of all family members side by side. We found that all TMBIM proteins possess the di-aspartyl pH sensor responsible for pH sensing identified in TMBIM6 and its bacterial homologue BsYetJ. TMBIM1-3 and TMBIM4-6 represent two phylogenetically distinct groups that are localized in the Go…