333 research outputs found
Chiasmus conspurcatus Perris 1857
No full text<i>Chiasmus conspurcatus</i> (Perris, 1857) <p> <i>Athysanus conspurcatus</i> Perris, 1857: 174.</p> <p> <i>Chiasmus conspurcatus</i> (Perris, 1857): Dlabola (1971a), Dlabola (1981), Mirzayans (1995), Abdollahi <i>et al</i>. (2015) [listed].</p> <p>Recorded distribution in Iran: Northeast, north, northwest, southwest and centre.</p>Published as part of <i>Mozaffarian, Fariba & Wilson, Michael R., 2016, A checklist of the leafhoppers of Iran (Hemiptera: Auchenorrhyncha: Cicadellidae), pp. 1-63 in Zootaxa 4062 (1)</i> on page 14, DOI: 10.11646/zootaxa.4062.1.1, <a href="http://zenodo.org/record/256796">http://zenodo.org/record/256796</a>
Phlepsius ornatus Perris 1857
No full text<i>Phlepsius ornatus</i> (Perris, 1857) <p> <i>Athysanus ornatus</i> Perris, 1857:147.</p> <p> <i>Phlepsius ornatus</i> (Perris, 1857): Nast (1972) [listed], Dlabola (1972) [listed], Dlabola (1981), Mirzayans (1995), Ozgen & Karsavuran (2009) [listed].</p> <p> <i>Phlepsius asiaticus</i> Zachvatkin, 1945: Dlabola (1960a), Dlabola (1964a) [listed]. Recorded distribution in Iran: West, northwest, north, northeast, southeast and south.</p>Published as part of <i>Mozaffarian, Fariba & Wilson, Michael R., 2016, A checklist of the leafhoppers of Iran (Hemiptera: Auchenorrhyncha: Cicadellidae), pp. 1-63 in Zootaxa 4062 (1)</i> on page 30, DOI: 10.11646/zootaxa.4062.1.1, <a href="http://zenodo.org/record/256796">http://zenodo.org/record/256796</a>
Inhibition of neural crest cell migration by aggregating chondroitin sulfate proteoglycans is mediated by their hyaluronan-binding region
No full textWe have recently shown that the large hyaluronan-aggregating chondroitin sulfate proteoglycan from cartilage (PG-LA) is unfavorable as a substrate for neural crest cell migration in vitro and that this macromolecule inhibits cell dispersion on fibronectin substrates when included in the medium (R. Perris and S. Johansson, 1987, J. Cell Biol. 105, 2511-2521). In this study we present data on the specificity of the migration-repressing activity of PG-LA and data on the molecular mechanisms by which the proteoglycan might impair neural crest cell motility. Soluble PG-LA potently impaired cell migration on substrates of laminin/laminin-nidogen, vitronectin, and collagen types I, III, IV, and VI. When tested in solid-phase binding assays, PG-LA bound avidly to substrates of collagen types I-III and V. Conversely, minimal amounts of the proteoglycan bound to substrates of laminin-nidogen, vitronectin, collagen types IV and VI, and fibronectin or to a proteolytic fragment encompassing its cell-binding domain (105 kDa). Preincubation of these substrates with soluble PG-LA prior to plating of the cells had no effect on their locomotory behavior. These results indicate that PG-LA affects neural crest cell movement primarily through an interaction with the cell surface, rather than by association with the cell motility-promoting substrate molecules. The molecular interaction of soluble PG-LA with neural crest cells was further examined by analyzing the effects of isolated domains of the proteoglycan on cell migration on fibronectin. Addition of chondroitin sulfate chains, the core protein free of glycosaminoglycans, the isolated hyaluronan-binding region (HABr), or a proteolytic fragment corresponding to the keratan sulfate-enriched domain of the PG-LA to neural crest cells migrating on fibronectin or the 105-kDa fibronectin fragment had no significant effect on their motility. After reduction and alkylation, PG-LA was considerably less efficient in perturbing cell movement on fibronectin substrates and virtually ineffective in altering migration on the 105-kDa fragment. In the presence of hyaluronan fragments of 16-30 monosaccharides in length, or an antiserum against the HABr, the migration repressing activity of PG-LA was reduced in a dose-dependent fashion. Furthermore, the inhibitory action of PG-LA was significantly reduced by treatment of the cells with Streptomyces hyaluronidase.(ABSTRACT TRUNCATED AT 400 WORDS
Proteoglycan control of cell movement during wound healing and cancer spreading
No full textBy virtue of their multifunctional nature, proteoglycans (PGs) are thought to govern the process of cell movement in numerous physiological and pathological contexts, spanning from early embryonic development to tumour invasion and metastasis. The precise mode by which they influence this process is still fragmentary, but evidence is accruing that they may affect it in a multifaceted manner. PGs bound to the plasma membrane mediate the polyvalent interaction of the cell with matrix constituents and with molecules of the neighbouring cells' surfaces; they modulate the activity of receptors implicated in the recognition of these components; and they participate in the perception and convergence of growth- and motility-promoting cues contributed by soluble factors. Through some of these interactions several PGs transduce to pro-motile cells crucial intracellular signals that are likely to be essential for their mobility. A regulated shedding of certain membrane-intercalated PGs seems to provide an additional level of control of cell movement. Coincidentally, matrix-associated PGs may govern cell migration by structuring permissive and non-permissive migratory paths and, when directly secreted by the moving cells, may alternatively create favourable or hostile microenvironments. To exert this latter, indirect effect on cell movement, matrix PGs strongly rely upon their primary molecular partners, such as hyaluronan, link proteins, tenascins, collagens and low-affinity cell surface receptors, whereas a further finer control is provided by a highly regulated proteolytic processing of the PGs accounted by both the migrating cells themselves and cells of their surrounding tissues. Overall, PGs seem to play an important role in determining the migratory phenotype of a cell by initiating, directing and terminating cell movement in a spatio-temporally controlled fashion. This implies that the "anti-adhesive and/or "anti-migratory" properties that have previously been assigned to certain PGs may be re-interpreted as being a means by which these macromolecules elaborate haptotaxis-like mechanisms imposing directionality upon the moving cells. Since these conditions would allow cells to be led to given tissue locations and become immobilized at these sites, a primary function may be ascribed to PGs in the dictation of a "stop or go" choice of the migrating cells. © 2005 Elsevier B.V./International Society of Matrix Biology. All rights reserved
Recent advances in defining the role of the extracellular Matrix in neural crest development
No full textSix3 controls the neural progenitor status in the murine CNS
No full textSix3, a homeodomain-containing transcriptional regulator belonging to the Six/so family, shows a defined spatiotemporal expression pattern in the developing murine telencephalon, suggesting that it may control the development of specific subsets of neural progenitors. We find that retrovirus-mediated misexpression of Six3 causes clonal expansion of isolated cortical progenitor cells by shortening their cell cycle and by prolonging their amplification period, while maintaining them in an immature precursor state. Our results show that the observed effects exerted by Six3 overexpression in mammalian brain depend strictly on the integrity of its DNA-binding domain, suggesting that Six3 action likely relies exclusively on its transcriptional activity. In vivo upregulation of Six3 expression in single progenitor cells of the embryonic telencephalon keeps them in an undifferentiated state. Our observations point to a role of Six3 in the control of the subtle equilibrium between proliferation and differentiation of defined precursor populations during mammalian neurogenesis. © The Author 2007. Published by Oxford University Press. All rights reserved
Chrysis indigotea Dufour & Perris 1840
No full text<i>Chrysis indigotea</i> DUFOUR & PERRIS, 1840 <p> <i>Chrysis indigotea</i> DUFOUR & PERRIS, 1840: 38. Syntypes; France (Lund, Paris).</p> <p> <i>Chrysis indica</i> SCHRANK, 1802: KIMSEY & BOHART 1991: 422.</p> <p> <i>Chrysis indica</i>: TARBINSKY 2000: 193 (key), 197 (cat., distr., Kyrgyzstan: Kyrgyzskiy crest, ur. Ala-Archa river).</p> <p>R e m a r k s: identification by TARBINSKY (2000) to be confirmed.</p> <p> In KIMSEY & BOHART (1991) and TARBINSKY (2000) under the name <i>Chrysis indica</i> SCHRANK, 1802. This name was not in use after 1899. In particular, before KIMSEY & BOHART (1991) it was listed only by two authors as a possible synonym of <i>C. indigotea</i> DUFOUR & PERRIS, 1840 (MOCSÁRY 1889; BISCHOFF 1913). After DUFOUR & PERRIS (1840) the name currently in use for the identification of this species was <i>C. indigotea</i>, which is still the name in current use (ICZN 1999: Article 23.9). Moreover, the type of <i>C. indica</i> is lost and its description could be also related to other species of this group, e.g. a small specimen of <i>C. iris</i> CHRIST. For these reasons I consider <i>Chrysis indigotea</i> as the valid name, and <i>C. indica</i> as <i>nomen dubium</i> and <i>species inquirenda</i>.</p> <p>D i s t r i b u t i o n: Kyrgyzstan. West Palaearctic: central and southern Europe, northern Africa, Asia Minor (LINSENMAIER 1959).</p>Published as part of <i>Rosa, Paolo, 2019, A new remarkable species in the Chrysis ignita group (Hymenoptera, Chrysididae) and an overview on Central Asian species, with new synonymies, pp. 397-417 in Linzer biologische Beiträge 51 (1)</i> on pages 408-409, DOI: <a href="http://zenodo.org/record/3758372">10.5281/zenodo.3758372</a>
Structural deciphering of the NG2/CSPG4 proteoglycan multifunctionality
No full textThe chondroitin sulfate proteoglycan 4 (CSPG4) gene encodes a transmembrane proteoglycan (PG) constituting the largest and most structurally complex macromolecule of the human surfaceome. Its transcript shows an extensive evolutionary conservation and, due to the elaborated intracellular processing of the translated protein, it generates an array of glycoforms with the potential to exert variant-specific functions. CSPG4-mediated molecular events are articulated through the interaction with more than 40 putative ligands and the concurrent involvement of the ectodomain and cytoplasmic tail. Alternating inside-out and outside-in signal transductions may thereby be elicited through a tight functional connection of the PG with the cytoskeleton and its regulators. The potential of CSPG4 to influence both types of signaling mechanisms is also asserted by its lateral mobility along the plasma membrane and its intersection with microdomain-restricted internalization and endocytic trafficking. Owing to the multitude of molecular interplays that CSPG4 may engage, and thanks to a differential phosphorylation of its intracellular domain accounted by crosstalking signaling pathways, the PG stands out for its unique capability to affect numerous cellular phenomena, including those purporting pathologic conditions. We discuss here the progresses made in advancing our understanding about the structural-functional bases for the ability of CSPG4 to widely impact on cell behavior, such as to highlight how its multivalency may be exploited to interfere with disease progression.Tamburini, E., Dallatomasina, A., Quartararo, J., Cortelazzi, B., Mangieri, D., Lazzaretti, M., Perris, R. Structural deciphering of the NG2/CSPG4 proteoglycan multifunctionality
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