SPODOBASE : an EST database for the lepidopteran crop pest Spodoptera

BACKGROUND: The Lepidoptera Spodoptera frugiperda is a pest which causes widespread economic damage on a variety of crop plants. It is also well known through its famous Sf9 cell line which is used for numerous heterologous protein productions. Species of the Spodoptera genus are used as model for pesticide resistance and to study virus host interactions. A genomic approach is now a critical step for further new developments in biology and pathology of these insects, and the results of ESTs sequencing efforts need to be structured into databases providing an integrated set of tools and informations. DESCRIPTION: The ESTs from five independent cDNA libraries, prepared from three different S. frugiperda tissues (hemocytes, midgut and fat body) and from the Sf9 cell line, are deposited in the database. These tissues were chosen because of their importance in biological processes such as immune response, development and plant/insect interaction. So far, the SPODOBASE contains 29,325 ESTs, which are cleaned and clustered into non-redundant sets (2294 clusters and 6103 singletons). The SPODOBASE is constructed in such a way that other ESTs from S. frugiperda or other species may be added. User can retrieve information using text searches, pre-formatted queries, query assistant or blast searches. Annotation is provided against NCBI, UNIPROT or Bombyx mori ESTs databases, and with GO-Slim vocabulary. CONCLUSION: The SPODOBASE database provides integrated access to expressed sequence tags (EST) from the lepidopteran insect Spodoptera frugiperda. It is a publicly available structured database with insect pest sequences which will allow identification of a number of genes and comprehensive cloning of gene families of interest for scientific community. SPODOBASE is available from URL

Establishment and analysis of a reference transcriptome for Spodoptera frugiperda

International audienceBackground Spodoptera frugiperda (Noctuidae) is a major agricultural pest throughout the American continent. The highly polyphagous larvae are frequently devastating crops of importance such as corn, sorghum, cotton and grass. In addition, the Sf9 cell line, widely used in biochemistry for in vitro protein production, is derived from S. frugiperda tissues. Many research groups are using S. frugiperda as a model organism to investigate questions such as plant adaptation, pest behavior or resistance to pesticides.ResultsIn this study, we constructed a reference transcriptome assembly (Sf_TR2012b) of RNA sequences obtained from more than 35 S. frugiperda developmental time-points and tissue samples. We assessed the quality of this reference transcriptome by annotating a ubiquitous gene family - ribosomal proteins - as well as gene families that have a more constrained spatio-temporal expression and are involved in development, immunity and olfaction. We also provide a time-course of expression that we used to characterize the transcriptional regulation of the gene families studied.ConclusionWe conclude that the Sf_TR2012b transcriptome is a valid reference transcriptome. While its reliability decreases for the detection and annotation of genes under strong transcriptional constraint we still recover a fair percentage of tissue-specific transcripts. That allowed us to explore the spatial and temporal expression of genes and to observe that some olfactory receptors are expressed in antennae and palps but also in other non related tissues such as fat bodies. Similarly, we observed an interesting interplay of gene families involved in immunity between fat bodies and antennae

Voluntary information during takeover bids : From the disclosure decision to its influence on shareholders

Cette thèse porte sur la diffusion volontaire d’informations lors d’OPA/OPE. Elle est constituée de trois articles s’intéressant à une étape différente du processus de diffusion d’informations dans ce contexte. Le premier article vise à expliquer la décision de diffusion volontaire des entreprises cibles par une étude des facteurs incitatifs à la diffusion lors de telles opérations. Les résultats montrent que cette décision découle principalement de l’influence de facteurs contextuels. Le deuxième article identifie, à partir d’une analyse lexicale des communiqués de presse volontaires, les stratégies discursives adoptées par les entreprises acquéreuses et cibles ainsi que les motivations sous-jacentes. Enfin, dans le troisième article, une expérimentation est conduite afin d’examiner l’influence des stratégies de diffusion d’informations et de gestion des impressions des entreprises cibles d’offres hostiles sur les actionnaires. Il s’avère que celles-ci modifient leur perception de l’offre et in fine leur décision d’accepter ou de rejeter l’opération.This thesis deals with voluntary disclosure of information during takeover bids. It consists of three articles that are concerned with a different step of the disclosure process in this context. The first article aims at explaining the voluntary disclosure decision of target companies by studying factors influencing disclosure during such transactions. The results highlight that this decision is mainly explained by the influence of contextual factors. The second article identifies, through a lexical analysis of voluntary press releases, the discourse strategies adopted by both bidding and target companies and the underlying motivations. Finally, in the third article, an experiment is conducted to investigate the influence of disclosure and impression management strategies of the targets of hostile bids on shareholders. It turns out that these strategies modify their perception of the bid and ultimately their decision to accept or reject the bid

Voluntary disclosure and investor reaction to downsizing announcements: A legitimacy perspective

International audienceThis paper investigates the determinants and consequences of firms’ decisions to disclose press releases to announce downsizing operations. We also examine the content of press releases and its influence on investor reactions to downsizing announcements. Considering downsizing operations as negative CSR events, we assume that managers use disclosure strategies to counter a potential legitimacy threat. Our sample consists of 227 downsizing operations announced between 2007 and 2012. We find that the disclosure of press releases is mainly driven by legitimacy-related factors. We also find that press releases are associated with more negative reactions than when there is no press release, particularly in the case of proactive operations. A content analysis of press releases indicates that investors penalize the use of proactive arguments, particularly when they are used to justify proactive operations. Overall, our results show that disclosure strategies and their consequences on the financial markets relate to a legitimacy perspective

Disclosure strategies in downsizing announcements: A legitimacy perspective

International audienc

Disclosure strategies in downsizing announcements: A legitimacy perspective

International audienc

Voluntary disclosure and investor reaction to downsizing announcements: A legitimacy perspective

International audienceThis paper investigates the determinants and consequences of firms’ decisions to disclose press releases to announce downsizing operations. We also examine the content of press releases and its influence on investor reactions to downsizing announcements. Considering downsizing operations as negative CSR events, we assume that managers use disclosure strategies to counter a potential legitimacy threat. Our sample consists of 227 downsizing operations announced between 2007 and 2012. We find that the disclosure of press releases is mainly driven by legitimacy-related factors. We also find that press releases are associated with more negative reactions than when there is no press release, particularly in the case of proactive operations. A content analysis of press releases indicates that investors penalize the use of proactive arguments, particularly when they are used to justify proactive operations. Overall, our results show that disclosure strategies and their consequences on the financial markets relate to a legitimacy perspective

Replacer l’humain au cœur du système… Quels défis pour la comptabilité de demain ?

L’organisation des systèmes de contrôle dans les organisations trouve ses origines dans la théorie de l’agence et la théorie des droits de propriété. Fondé sur l’idée que le dirigeant (mandataire) doit agir en priorité dans l’intérêt du propriétaire (le principal ou le mandant), le modèle actionnarial s’est imposé et plusieurs auteurs soulignent que la comptabilité, notamment, serait au service du capitalisme financier et donc des actionnaires (Capron, 2005 ; Chiapello, 2005 ; Berland et Pezet, 2009). La préférence donnée aux investisseurs s’expliquerait par les ressources, au sens comptable, qu’ils financent et par le risque que comporte une telle relation. Ce principe est discutable dans une économie dématérialisée où les actifs incorporels jouent un rôle-clé. Les scandales financiers récents, dont la faillite d’Enron est le symbole, ont montré les défauts du système actuel. En outre, ces situations donnent une visibilité inhabituelle à la comptabilité et révèlent ses enjeux d’ordres social et politique (De Blic, 2004). Un modèle alternatif, élargi aux parties prenantes, tente de s’imposer dans la théorie et dans les faits. Il repose sur l’idée que des parties autres que les investisseurs (dirigeants, salariés, entreprises partenaires, clients et fournisseurs, collectivités locales, etc.) sont détentrices d’intérêts sur l’entreprise et peuvent prétendre à exercer un rôle effectif dans son système de gouvernance. À une vision restrictive de la responsabilité de la firme, exclusivement économique et tournée vers les actionnaires (Friedman, 1970), s’oppose une conception élargie, qualifiée de sociale ou sociétale, embrassant l’ensemble des parties prenantes (Freeman, 1984 ; Hill et Jones, 1992 ; Charreaux et Desbrières, 1998)