344 research outputs found
Environmental factors and effects on breeding performances and housing in small laboratory rodents: A technical report
Based on their professional experience in large scale production of laboratory rodents, the authors report on some documented cases showing the effects of environmental factors on reproductive performances of the rodent strains they produce. Beyond continuation of the effect of a Simple environmental factor (temperature, light) the reported cases show that environmental effects must not be systematically generalized to several strains or, even less, to several species.Moreover, the incidence of associated (complex) factors, which cannot be evaluated without the opportunity of having a control sample must be emphasized. This last point is of major importance when comparing results coming from different laboratories although the maintain environmental factors are a priori identical
Impacto de la siega y el pastoreo de las ovejas en arañas y carábidos activos del suelo de algunos marjales salinos intermareales (oeste de Francia)
The aims of this study were to characterize spider (Araneae) and ground beetle (Coleoptera, Carabidae) communities in managed (cutting and sheep grazing) and non–managed salt marshes and to assess the efficiency of management regimes in these particular ecosystems. The two groups were studied during 2002 in salt marshes of the Mont Saint–Michel Bay (NW France) using pitfall traps. By opening soil and vegetation structures cutting and grazing enhanced the abundances of some halophilic species of spiders and ground beetles. Nevertheless, grazing appeared to be too intensive as spider species richness decreased. We discuss the implications of management practices in terms of nature conservation and their application in the particular area of intertidal salt marshes.
Key words: Management, Conservation value, Halophilic species, Arthropods.El objetivo de este estudio es caracterizar las comunidades de arañas (Araneae) y escarabajos del suelo o cárabos (Coleoptera, Carabidae) en marjales salinos gestionados (siega y pastoreo) y no gestionados y, por lo tanto, valorar la eficacia de lo regĂmenes de gestiĂłn en estos ecosistemas particulares. Ambos grupos fueron estudiados durante el año 2002 en distintos marjales salinos de la bahĂa de Mont Saint–Michel (NO de Francia) mediante trampas de intercepciĂłn. La siega y el pastoreo, al abrir el suelo y las estructuras vegetales, hacĂan aumentar la abundancia de algunas especies halĂłfilas de arañas y cárabos. No obstante, parece ser que el pastoreo era demasiado intensivo ya que la riqueza de especies de arañas disminuĂa. Se discuten las implicaciones de las prácticas de gestiĂłn en tĂ©rminos de la conservaciĂłn de la naturaleza y tambiĂ©n su aplicaciĂłn en zonas tan especiales como son los marjales salinos intermareales.
Palabras clave: GestiĂłn, Valor conservativo, Especies halĂłfilas, ArtrĂłpodos
The actual annual occurrence of the green lacewings of northwestern Europe (Neuroptera: Chrysopidae)
Quantitative surveys of chrysopids from northwestern Europe were analysed. A total of thirty-five species are known within the zone although only twenty-six were recorded. Only the common green lacewings (i.e. the sibling species of the Chrysoperla carnea complex, here not differentiated) were elsewhere abundant comprising more than 3/4 of the specimens in all countries and reaching 97 % in Belgium. For the scarcer species, comments are given on their enhanced geographic range. The French fauna shows 19 species, six are exceptional (< 0.1%) such as the Atlanto-Mediterranean Dichochrysa picteti . Five species are considered rare (1<Q ≤ 5 %): Chrysopa perla , Ch. phyllochroma , Dichochrysa flavifrons, D. inornata and D. prasina. The fauna of both Great Britain and Ireland has the same faunistical richness but manifests a more balanced equitability. Chrysopa perla , Dichochrysa flavifrons and Cunctochrysa albolineata are uncommon (5 < Q ≤ 15 %), the others are at least rare. Belgium and Luxemburg gave 16 species and a very low diversity. Hypochrysa elegans, Nineta vittata, N. principiae and Chrysopa pallens are exceptional. Comments are given on some underestimated species, such as Dichochrysa mariana and Cunctochrysa bellifontensis not unanimously agreed, and D. abdominalis too recently re-instated to be identified in many collections
1H, 13C, 15N backbone resonance assignment of apo and ADP-ribose bound forms of the macro domain of Hepatitis E virus through solution NMR spectroscopy
International audienceAbstract The genome of Hepatitis E virus (HEV) is 7.2 kilobases long and has three open reading frames. The largest one is ORF1, encoding a non-structural protein involved in the replication process, and whose processing is ill-defined. The ORF1 protein is a multi-modular protein which includes a macro domain (MD). MDs are evolutionarily conserved structures throughout all kingdoms of life. MDs participate in the recognition and removal of ADP-ribosylation, and specifically viral MDs have been identified as erasers of ADP-ribose moieties interpreting them as important players at escaping the early stages of host-immune response. A detailed structural analysis of the apo and bound to ADP-ribose state of the native HEV MD would provide the structural information to understand how HEV MD is implicated in virus-host interplay and how it interacts with its intracellular partner during viral replication. In the present study we present the high yield expression of the native macro domain of HEV and its analysis by solution NMR spectroscopy. The HEV MD is folded in solution and we present a nearly complete backbone and sidechains assignment for apo and bound states. In addition, a secondary structure prediction by TALOS + analysis was performed. The results indicated that HEV MD has a α/β/α topology very similar to that of most viral macro domains
An improved synthesis, crystal structures, and metallochromism of salts of [Ru(tolyl-terpy)(CN)(3)](-)
The previously reported complex [Ru(ttpy)(CN)(3)] [ttpy = 4'(p-tolyl)-2,2':6',2"-terpyridine] is conveniently synthesised by reaction of ttpy with Ru(dmso)(4)Cl-2 to give [Ru(ttpy)(dmso)Cl-2], which reacts in turn with KCN in aqueous ethanol to afford [Ru(ttpy)(CN)(3)] which was isolated and crystallographically characterised as both its (PPN)(+) and K+ salts. The K+ salt contains clusters containing three complex anions and three K+ cations connected by end-on and side-on cyanide ligation to the K+ ions. The solution speciation behaviour of [Ru(ttpy)(CN)(3)] was investigated with both Zn2+ and K+ salts in MeCN, a solvent sufficiently non-competitive to allow the added metal cations to associate with the complex anion via the externally-directed cyanide lone pairs. UV-Vis spectroscopic titration of (PPN)[Ru(ttpy)(CN)(3)] with Zn(ClO4)(2) showed a blue shift of 2900 cm (1) in the (MLCT)-M-1 absorption manifold due to the ` metallochromism' effect; a series of distinct binding events could be discerned corresponding to formation of 4:1, 1:1 and then 1:3 anion: cation adducts, all with high formation constants, as the titration proceeded. In contrast titration of (PPN)[Ru(ttpy)(CN)(3)] with the more weakly Lewis-acidic KPF6 resulted in a much smaller blue-shift of the 1MLCT absorptions, and the titration data corresponded to formation of 1:1 and then 2: 1 cation: anion adducts with weaker stepwise association constants of the order of 10(4) and then 10(3) M (1). Although association of [Ru(ttpy)(CN)(3)] resulted in a blue-shift of the (MLCT)-M-1 absorptions, the luminescence was steadily quenched, as raising the (MLCT)-M-3 level makes radiationless decay via a lowlying (MC)-M-3 state possible. (C) 2010 Elsevier B. V. All rights reserved
Divisible E-Cash from Constrained Pseudo-Random Functions
International audienceElectronic cash (e-cash) is the digital analogue of regular cash which aims at preservingusers’ privacy. Following Chaum’s seminal work, several new features were proposed for e-cash toaddress the practical issues of the original primitive. Among them,divisibilityhas proved very usefulto enable efficient storage and spendings. Unfortunately, it is also very difficult to achieve and, todate, quite a few constructions exist, all of them relying on complex mechanisms that can only beinstantiated in one specific setting. In addition security models are incomplete and proofs sometimeshand-wavy.In this work, we first provide a complete security model for divisible e-cash, and we study the linkswith constrained pseudo-random functions (PRFs), a primitive recently formalized by Boneh andWaters. We exhibit two frameworks of divisible e-cash systems from constrained PRFs achievingsome specific properties: either key homomorphism or delegability. We then formally prove theseframeworks, and address two main issues in previous constructions: two essential security notionswere either not considered at all or not fully proven. Indeed, we introduce the notion ofclearing,which should guarantee that only the recipient of a transaction should be able to do the deposit,and we show theexculpability, that should prevent an honest user to be falsely accused, was wrongin most proofs of the previous constructions. Some can easily be repaired, but this is not the casefor most complex settings such as constructions in the standard model. Consequently, we providethe first construction secure in the standard model, as a direct instantiation of our framework
Long-term follow-up after endoscopic resection for superficial esophageal squamous cell carcinoma: a multicenter Western studyAbstract
Background Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are the first-line treatments for superficial esophageal squamous cell carcinoma (SCC). This study aimed to compare long-term clinical outcome and oncological clearance between EMR and ESD for the treatment of superficial esophageal SCC.
Methods We conducted a retrospective multicenter study in five French tertiary care hospitals. Patients treated by EMR or ESD for histologically proven superficial esophageal SCC were included consecutively.
Results Resection was performed for 148 tumors (80 EMR, 68 ESD) in 132 patients. The curative resection rate was 21.3 % in the EMR group and 73.5 % in the ESD group (P < 0.001). The recurrence rate was 23.7 % in the EMR group and 2.9 % in the ESD group (P = 0.002). The 5-year recurrence-free survival rate was 73.4 % in the EMR group and 95.2 % in the ESD group (P = 0.002). Independent factors for cancer recurrence were resection by EMR (hazard ratio [HR] 16.89, P = 0.01), tumor infiltration depth ≥ m3 (HR 3.28, P = 0.02), no complementary treatment by chemoradiotherapy (HR 7.04, P = 0.04), and no curative resection (HR 11.75, P = 0.01). Risk of metastasis strongly increased in patients with tumor infiltration depth ≥ m3, and without complementary chemoradiotherapy (P = 0.02).
Conclusion Endoscopic resection of superficial esophageal SCC was safe and efficient. Because it was associated with an increased recurrence-free survival rate, ESD should be preferred over EMR. For tumors with infiltration depths ≥ m3, chemoradiotherapy reduced the risk of nodal or distal metastasis
Crystal structure of the RNA polymerase domain of the West Nile Virus non-structural protein 5
Viruses of the family Flaviviridae are important human and animal pathogens. Among them, the Flaviviruses dengue ( DENV) and West Nile ( WNV) cause regular outbreaks with fatal outcomes. The RNA-dependent RNA polymerase ( RdRp) activity of the non-structural protein 5 ( NS5) is a key activity for viral RNA replication. In this study, crystal structures of enzymatically active and inactive WNV RdRp domains were determined at 3.0- and 2.35-angstrom resolution, respectively. The determined structures were shown to be mostly similar to the RdRps of the Flaviviridae members hepatitis C and bovine viral diarrhea virus, although with unique elements characteristic for the WNVRdRp. Using a reverse genetic system, residues involved in putative interactions between the RNA-cap methyltransferase ( MTase) and the RdRp domain of Flavivirus NS5 were identified. This allowed us to propose a model for the structure of the full-length WNV NS5 by in silico docking of the WNV MTase domain ( modeled from our previously determined structure of the DENV MTase domain) onto the RdRp domain. The Flavivirus RdRp domain structure determined here should facilitate both the design of anti-Flavivirus drugs and structure-function studies of the Flavivirus replication complex in which the multifunctional NS5 protein plays a central role
- …