Search results for "Trace"
showing 10 items of 3218 documents
The Origin of Metazoan Complexity: Porifera as Integrated Animals
2011
SYNOPSIS. Sponges [Porifera] are the phylogenetically oldest metazoan phylum still extant today; they share the closest relationship with the hypothetical common metazoan ancestor, the Urmetazoa. During the past 8 years cDNAs coding for proteins involved in cell-cell- and cell-tissue interaction have been cloned from sponges, primarily from Suberites domuncula and Geodia cydonium and their functions have been studied in vivo as well as in vitro. Also, characteristic elements of the extracellular matrix have been identified and cloned. Those data confirmed that all metazoan phyla originate from one ancestor, the Urmetazoa. The existence of cell adhesion molecules allowed the emergence of a c…
The unique skeleton of siliceous sponges (Porifera; Hexactinellida and Demospongiae) that evolved first from the Urmetazoa during the Proterozoic: a …
2007
Abstract. Sponges (phylum Porifera) had been considered as an enigmatic phylum, prior to the analysis of their genetic repertoire/tool kit. Already with the isolation of the first adhesion molecule, galectin, it became clear that the sequences of the sponge cell surface receptors and those of the molecules forming the intracellular signal transduction pathways, triggered by them, share high similarity to those identified in other metazoan phyla. These studies demonstrated that all metazoan phyla, including the Porifera, originate from one common ancestor, the Urmetazoa. The sponges evolved during a time prior to the Ediacaran-Cambrian boundary (542 million years ago (myr)). They appeared du…
Probable root structures and associated trace fossils from the Lower Pleistocene calcarenites of favignana island, southern italy: dilemmas of interp…
2012
Two types of large, branched structures from the Lower Pleistocene (Calabrian) high-energy calcarenites of Favignana Island are described: Faviradixus robustus gen. et sp. nov. and Egadiradixus rectibrachiatus gen. et sp. nov. They may be interpreted as root structures of large plants, trees and trees or shrubs, respectively. The former taxon co-occurs with the marine animal trace fossils Ophiomorpha nodosa , Ophiomorpha isp., Thalassinoides isp. and Beaconites isp. The interpretation as root structures although tentative is probable and can be related to short emergence episodes for the formation of E . rectibrachiatus or to longer emergence, responsible for the discontinuity at the base o…
DSD-1-Proteoglycan/Phosphacan and Receptor Protein Tyrosine Phosphatase-Beta Isoforms during Development and Regeneration of Neural Tissues
2007
Interactions between neurons and glial cells play important roles in regulating key events of development and regeneration of the CNS. Thus, migrating neurons are partly guided by radial glia to their target, and glial scaffolds direct the growth and directional choice of advancing axons, e.g., at the midline. In the adult, reactive astrocytes and myelin components play a pivotal role in the inhibition of regeneration. The past years have shown that astrocytic functions are mediated on the molecular level by extracellular matrix components, which include various glycoproteins and proteoglycans. One important, developmentally regulated chondroitin sulfate proteoglycan is DSD-1-PG/phosphacan,…
Dehydration of yeast: Changes in the intracellular content of Hsp70 family proteins
2008
Abstract Yeast is known to experience in natural and industrial conditions cycles of dehydration–rehydration. Several molecular mechanisms can be triggered in response to this and other environmental stressors and to rescue yeast cells of the cytotoxic effect. Since heat shock proteins constitute one of the most important systems of the response to stress we studied whether the pre-induced major stress protein, Hsp70, can cope with yeast cell drying. To induce Hsp70 expression the cells of two yeast species, Saccharomyces cerevisiae and Debaryomyces hansenii , were subjected to non-lethal heat shock. It was found that during yeast culture growth Hsp70 accumulation occurred at the exponentia…
Toxicity of the extracellular products ofVibrio damsela isolated from diseased fish
1993
In this work we analyzed the pathogenic in vivo and in vitro activities for both fish and mammals of extracellular products (ECP) of several isolates of Vibrio damsela implicated in disease problems in marine culture. The ECP from all the strains were strongly lethal for fish (LD50 ranging from 0.06 to 3.7 μg protein/g fish) and mice (LD50 ranging from 0.02 to 0.43 μg protein/g mouse), causing death between 4 and 72 h after inoculation. These ECP samples possessed low proteolytic activity without production of caseinase, gelatinase, or elastase. However, most of them showed remarkable phospholipase and hemolytic activity for sheep, human, and turbot red blood cells. In addition, all the ECP…
Unraveling the origin of the Late Triassic multitaxic bone accumulation at Krasiejów (S Poland) by diagenetic analysis
2012
Abstract A study of aquatic and terrestrial vertebrate remains from a bonebed in the Late Triassic continental succession near Krasiejow (S Poland) shows it was deposited by a single catastrophic event, perhaps a flood. Hardparts of Metoposaurus, Paleorhinus, and Stagonolepis show sedimentary infill and geochemical evidence for early diagenesis at different times and in different microenvironments. The infills in the aquatic animal bones (sediment, pyrite and calcite) show deposition in a freshwater environment, while those in the terrestrial Stagonolepis remains (mainly barite) point to an arid terrestial environment. The trace element content of the remains, together with the absence of a…
Deux nouvelles traces de pas de Dinosaures du Trias supérieur de la bordure cévenole (la Grand-Combe, Sud-Est de la France)
2000
Resume Dans une formation sommitale a Argiles bariolees du Trias superieur francais, deux niveaux a traces depas inedites de Dinosaures ont ete decouverts. Elles se rapportent a l'association Otozoum/Grallator qui n'a jamais ete definie precisement en Europe. Sa position stratigraphique precise dans la serie triasique et la comparaison avec les associations ichnologiques des USA et d'Afrique du Sud, confirment l'âge Norien des niveaux a empreintes. Otozoum grandcombensis nov. ichnosp. correspond a des traces de pieds et de mains tetradactyles de meme taille, laissees par un animal bipede occasionnellement quadrupede. Il s'agissait probablement d'un, grand Prosauropode, d'une dizaine de m de…
Pathogenesis of Atherosclerosis: The Alternative Hypothesis
1998
The concept that oxidation is the major single event underlying the transformation of LDL to a proinflammatory molecule dominates the world literature. An alternative hypothesis on the pathogenesis of atherosclerosis will be presented here. We have found that nonoxidative, enzymatic modification of LDL with ubiquitous enzymes also transforms the molecule to an atherogenic moiety. Enzymatically altered LDL (E-LDL) shares major properties in common with lipoproteins that have been isolated from atherosclerotic lesions. It activates complement and is recognized by a scavenger receptor on human macrophages, thus inducing foam cell formation. Uptake of E-LDL is accompanied by induction of MCP−1 …
Medicine among métis, phrónesis and téchne
2010
Cosi come si presenta la pillola del giorno dopo puo essere utilizzata in modo efficace fino a 72 ore dopo il rapporto sessuale non protetto. Tuttavia, in alcuni casi, questo periodo puo essere troppo breve. Per tale motivo, e stata commercializzata per la prima volta una pillola, l’acetato ulipristal (Ellaone), per la contraccezione d’emergenza post-coitale fino a 120 ore (5 giorni) dopo i rapporti sessuali non protetti o nel caso di insuccesso del contraccettivo. Un aspetto importante da considerare nella valutazione etica di un farmaco usato per la contraccezione d’emergenza e il suo meccanismo d’azione, in quanto tale valutazione sara molto diversa se il farmaco agisce inibendo o ritard…