Search results for "biologie"
showing 10 items of 256 documents
Halfway up the trophic chain: development of parasite communities in the sparid fish Boops boops
2007
SUMMARYWe examined the patterns of composition and structure of parasite communities in the Mediterranean sparid fish Boops boops along a gradient of fish sizes, using a large sample from a single population. We tested the hypothesis that species forming the core of the bogue parasite fauna (i.e. species which have a wide geographical range and are responsible for recognizable community structure) appear early in the fish ontogeny. The sequential community development observed supported the prediction that core species appear in the fish population earlier than rare and stochastic species. There was also a strong correlation between the order of ‘arrival’ of the species and their overall pr…
Rapid differentiation between livestock-associated and livestock-independent Staphylococcus aureus CC398 clades.
2013
Staphylococcus aureus clonal complex 398 (CC398) isolates cluster into two distinct phylogenetic clades based on single-nucleotide polymorphisms (SNPs) revealing a basal human clade and a more derived livestock clade. The scn and tet(M) genes are strongly associated with the human and the livestock clade, respectively, due to loss and acquisition of mobile genetic elements. We present canonical single-nucleotide polymorphism (canSNP) assays that differentiate the two major host-associated S. aureus CC398 clades and a duplex PCR assay for detection of scn and tet (M). The canSNP assays correctly placed 88 S. aureus CC398 isolates from a reference collection into the human and livestock clade…
Cytotoxic flavonoids from two Lonchocarpus species
2019
A new isoflavone, 4′-prenyloxyvigvexin A (1) and a new pterocarpan, (6aR,11aR)-3,8-dimethoxybitucarpin B (2) were isolated from the leaves of Lonchocarpus bussei and the stem bark of Lonchocarpus eriocalyx, respectively. The extract of L. bussei also gave four known isoflavones, maximaisoflavone H, 7,2′-dimethoxy-3′,4′-methylenedioxyisoflavone, 6,7,3′-trimethoxy-4′,5′-methylenedioxyisoflavone, durmillone; a chalcone, 4-hydroxylonchocarpin; a geranylated phenylpropanol, colenemol; and two known pterocarpans, (6aR,11aR)-maackiain and (6aR,11aR)-edunol. (6aR,11aR)-Edunol was also isolated from the stem bark of L. eriocalyx. The structures of the isolated compounds were elucidated by spectrosco…
L'Analogie chez Aristote
2021
Revue de philosophie dont l’objet est de montrer, d’interroger ou d’évaluer les comparaisons effectives dans les différents champs disciplinaires, Analogia est une publication scientifique annuelle de l’IPC.Chaque numéro réunit un conseil scientifique nouveau chargé de sélectionner les contributions en double aveugle.L’Analogie chez Aristote.Sous la direction d’Emmanuel Brochier.Conseil scientifique :- Katerina Ierodiakonou (Genève – Athènes)- André Laks (Paris)- Benjamin C. Morison (Princeton)- Jean-Luc Solère (Boston)Sommaire :- Présentation, par Emmanuel Brochier, p. 5 ;- Christof Rapp : "Spotting similarities between disparate items" Observations on the use of analogy in Aristotle’s met…
Translocation Biosensors – Cellular System Integrators to Dissect CRM1-Dependent Nuclear Export by Chemicogenomics
2009
Fluorescent protein biosensors are powerful cellular systems biology tools for dissecting the complexity of cellular processes with high spatial and temporal resolution. As regulated nucleo-cytoplasmic transport is crucial for the modulation of numerous (patho)physiological cellular responses, a detailed understanding of its molecular mechanism would open up novel options for a rational manipulation of the cell. In contrast to genetic approaches, we here established and employed high-content cellular translocation biosensors applicable for dissecting nuclear export by chemicogenomics. A431 cell lines, stably expressing a translocation biosensor composed of glutathione S-transferase, GFP and…
Towards a dendrochronologically refined date of the Laacher See eruption around 13,000 years ago
2020
Highlights • Previous age estimates of the Laacher See Eruptions (LSE) around 12,900 years are still diverging and imprecise. • The combination of dendrochronology, wood anatomy, and 14C measurements holds the potential to establish a precise LSE date. • An absolute calendric date of the LSE would improve the synchronization of European Late Glacial to Holocene archives. Abstract The precise date of the Laacher See eruption (LSE), central Europe’s largest Late Pleistocene volcanic event that occurred around 13,000 years ago, is still unknown. Here, we outline the potential of combined high-resolution dendrochronological, wood anatomical and radiocarbon (14C) measurements, to refine the age …
Focal DNA Copy Number Changes in Neuroblastoma Target MYCN Regulated Genes
2013
Neuroblastoma is an embryonic tumor arising from immature sympathetic nervous system cells. Recurrent genomic alterations include MYCN and ALK amplification as well as recurrent patterns of gains and losses of whole or large partial chromosome segments. A recent whole genome sequencing effort yielded no frequently recurring mutations in genes other than those affecting ALK. However, the study further stresses the importance of DNA copy number alterations in this disease, in particular for genes implicated in neuritogenesis. Here we provide additional evidence for the importance of focal DNA copy number gains and losses, which are predominantly observed in MYCN amplified tumors. A focal 5 kb…
Taspase1: a 'misunderstood' protease with translational cancer relevance
2015
Proteolysis is not only a critical requirement for life, but the executing enzymes also play important roles in numerous pathological conditions, including cancer. Therefore, targeting proteases is clearly relevant for improving cancer patient care. However, to effectively control proteases, a profound knowledge of their mechanistic function as well as their regulation and downstream signalling in health and disease is required. The highly conserved protease Threonine Aspartase1 (Taspase1) is overexpressed in numerous liquid and solid malignancies and was characterized as a 'non-oncogene addiction' protease. Although Taspase1 was shown to cleave various regulatory proteins in humans as well…
A multilevel statistical toolkit to study animal social networks: the Animal Network Toolkit Software (ANTs) R package
2020
Abstract The possible role played by individual attributes, sociodemographic characteristics and/or ecological pressures in the interaction between animals and the development of social relationships between them is of great interest in animal ecology and evolutionary biology. Social Network Analysis is an ideal tool to study these types of questions. The Animal Network Toolkit Software (ANTs) R package was specifically developed to provide all the different social network analysis techniques currently used in the study of animal social networks. This global package enables users to (1) compute global, polyadic and nodal network measures; (2) perform data randomisation: data stream and netw…
Follow-up trends of parasite community alteration in a marine fish after the Prestige oil-spill: shifting baselines?
2008
This study evaluates the follow-up trends in the composition and structure of the parasite communities in the marine sparid Boops boops after the Prestige oil-spill. A total of 400 fish comprising 11 seasonal samples was analyzed from three impacted localities on the Atlantic coast of Spain. A large number of parasite species was recovered only after the spill thus suggesting a substantial alteration of the marine food webs. Post-spill communities exhibited higher richness and abundance due to the significant changes in the abundance of the common species, the latter indicating accelerated parasite transmission rates. Multivariate analyses at two nested scales detected a directional trend i…