Search results for "sequence"
showing 10 items of 4987 documents
Expression of the human XPB/ERCC-3 excision repair gene-homolog in the sponge Geodia cydonium after exposure to ultraviolet radiation.
1998
Abstract The marine demosponge Geodia cydonium encodes a gene, termed GCXPB , which displays 62% identity to the human XPB/ERCC-3 gene that specifically corrects the repair defect in xeroderma pigmentosum and in Cockayne's syndrome. The cDNA was isolated and characterized the deduced aa sequence, XPB_GEOCY, with the calculated size of 91,541 Da comprises the characteristic domains found in the related helicases. Phylogenetic tree analysis revealed that the sponge sequence is grouped to the metazoan related XPB/ERCC-3 polypeptides. Northern Blot analyses have been performed with sponge samples collected at different depths, thus exposed to different intensities of UV sunlight in the field. T…
The diversity and evolution of chelicerate hemocyanins
2012
Abstract Background Oxygen transport in the hemolymph of many arthropod species is facilitated by large copper-proteins referred to as hemocyanins. Arthropod hemocyanins are hexamers or oligomers of hexamers, which are characterized by a high O2 transport capacity and a high cooperativity, thereby enhancing O2 supply. Hemocyanin subunit sequences had been available from horseshoe crabs (Xiphosura) and various spiders (Araneae), but not from any other chelicerate taxon. To trace the evolution of hemocyanins and the emergence of the large hemocyanin oligomers, hemocyanin cDNA sequences were obtained from representatives of selected chelicerate classes. Results Hemocyanin subunits from a sea s…
Distinct Clones of Yersinia pestis Caused the Black Death
2010
From AD 1347 to AD 1353, the Black Death killed tens of millions of people in Europe, leaving misery and devastation in its wake, with successive epidemics ravaging the continent until the 18th century. The etiology of this disease has remained highly controversial, ranging from claims based on genetics and the historical descriptions of symptoms that it was caused by Yersinia pestis to conclusions that it must have been caused by other pathogens. It has also been disputed whether plague had the same etiology in northern and southern Europe. Here we identified DNA and protein signatures specific for Y. pestis in human skeletons from mass graves in northern, central and southern Europe that …
A detailed study of the rise phase of a long duration X-ray flare in the young star TWA 11B
2010
We analyzed a long duration flare observed in a serendipitous XMM-Newton detection of the M star CD-39 7717B (TWA 11B), member of the young stellar association TW Hya (~ 8 Myr). Only the rise phase (with a duration of ~ 35 ks) and possibly the flare peak were observed. We took advantage of the high count-rate of the X-ray source to carry out a detailed analysis of its spectrum during the whole exposure. After a careful analysis, we interpreted the rise phase as resulting from the ignition of a first group of loops (event A) which triggered a subsequent two-ribbon flare (event B). Event A was analyzed using a single-loop model, while a two-ribbon model was applied for event B. Loop semi-leng…
New view of the corona of classical T Tauri stars: Effects of flaring activity in circumstellar disks
2019
Classical T Tauri stars (CTTSs) are young low-mass stellar objects accreting mass from their circumstellar disks. They are characterized by high levels of coronal activity as revealed by X-ray observations. This activity may affect the disk stability and the circumstellar environment. Here we investigate if an intense coronal activity due to flares occurring close to the accretion disk may perturb the inner disk stability, disrupt the inner part of the disk and, possibly, trigger accretion phenomena with rates comparable with those observed. We model a magnetized protostar surrounded by an accretion disk through 3D magnetohydrodinamic simulations. We explore cases characterized by a dipole …
Fast Secure Routing for Highly Mobile Large-Scale Ad-Hoc Vehicular Networks
2009
In highly mobile large-scale vehicular ad-hoc networks, routing protocols must be fast and efficient in terms of low routing discovery delay and communication overhead to support the applications such as car talk. Such requirement becomes more difficult to achieve when inducing security enhancement to tackle the authentication of routing messages. In this paper, we propose a lightweight (fast) secure routing protocol, Secure Proactive Tree-based Routing (SPTR) to hit these two points. SPTR makes use of the characteristics of VANET networks, that is, the traffic originates from or terminates at the gateway or road side unit. SPRT also takes advantages of certificate-less ID-based cryptograph…
Multipath extensions to the DYMO routing protocol
2007
Multipath routing is a technique that can improve performance, specially in mobile ad hoc networks. Due to traffic dispersion it can perform load balancing; minimize the energy consumed by nodes or prevent traffic analysis. In this work we focus on enhancing the DYMO protocol to support multipath routing. We study the impact of traffic dispersion on both UDP and TCP traffic when varying a set of parameters.
Killer toxin-secreting double-stranded RNA mycoviruses in the yeasts Hanseniaspora uvarum and Zygosaccharomyces bailii.
1994
Killer toxin-secreting strains of the yeasts Hanseniaspora uvarum and Zygosaccharomyces bailii were shown to contain linear double-stranded RNAs (dsRNAs) that persist within the cytoplasm of the infected host cell as encapsidated virus-like particles. In both yeasts, L- and M-dsRNAs were associated with 85-kDa major capsid protein, whereas the additional Z-dsRNA (2.8 kb), present only in the wild-type Z. bailii killer strain, was capsid protein, whereas the additional Z-dsRNA (2.8 kb), present only in the wild-type Z. bailii killer strain, was shown to be encapsidated by a 35-kDa coat protein. Although Northern (RNA) blot hybridizations indicated that L-dsRNA from Z. bailii is a LA species,…
Sex-ratio of Skylark Alauda arvensis broods in relation to timing of breeding.
2006
4 pages; International audience; Capsule Earlier broods tend to be more male biased than later broods.
Impact des invertébrés sur les fonctions des sols et leurs applications dans les systèmes sol-plante
2017
EABIOMEAGROSUP; De par leur structure tridimensionnelle, leur large gamme de porosité, la diversité de leurs caractéristiques physicochimiques et des conditions microclimatiques, les sols abritent un nombre considérable, parfois inestimable d'organismes. Au sein des agroécosystèmes, les enjeux sont de comprendre les relations entre la plante cultivée et son environnement biophysique incluant les interactions biologiques et les effets de la biodiversité des organismes des sols. L’impact de la faune du sol sur la production primaire peut être vu au travers de leur effet sur les fonctions de (i) recyclage des nutriments, (ii) entretien de la stabilité/structure du sol, (iii) contrôle des bioag…