Footprints of a trypanosomatid RNA world: pre-small subunit rRNA processing by spliced leader addition trans-splicing

The addition of a capped mini-exon [spliced leader (SL)] through trans-splicing is essential for the maturation of RNA polymerase (pol) II-transcribed polycistronic pre-mRNAs in all members of the Trypanosomatidae family. This process is an inter-molecular splicing reaction that follows the same basic rules of cis-splicing reactions. In this study, we demonstrated that mini-exons were added to precursor ribosomal RNA (pre-rRNA) are transcribed by RNA pol I, including the 5' external transcribed spacer (ETS) region. Additionally, we detected the SL-5'ETS molecule using three distinct methods and located the acceptor site between two known 5'ETS rRNA processing sites (A' and A1) in four different trypanosomatids. Moreover, we detected a polyadenylated 5'ETS upstream of the trans-splicing acceptor site, which also occurs in pre-mRNA trans-splicing. After treatment with an indirect trans-splicing inhibitor (sinefungin), we observed SL-5'ETS decay. However, treatment with 5-fluorouracil (a precursor of RNA synthesis that inhibits the degradation of pre-rRNA) led to the accumulation of SL-5'ETS, suggesting that the molecule may play a role in rRNA degradation. The detection of trans-splicing in these molecules may indicate broad RNA-joining properties, regardless of the polymerase used for transcription.

A directed approach for the identification of transcripts harbouring the spliced leader sequence and the effect of trans-splicing knockdown in Schistosoma mansoni

Schistosomiasis is a major neglected tropical disease caused by trematodes from the genus Schistosoma. Because schistosomes exhibit a complex life cycle and numerous mechanisms for regulating gene expression, it is believed that spliced leader (SL) trans-splicing could play an important role in the biology of these parasites. The purpose of this study was to investigate the function of trans-splicing in Schistosoma mansoni through analysis of genes that may be regulated by this mechanism and via silencing SL-containing transcripts through RNA interference. Here, we report our analysis of SL transcript-enriched cDNA libraries from different S. mansoni life stages. Our results show that the trans-splicing mechanism is apparently not associated with specific genes, subcellular localisations or life stages. In cross-species comparisons, even though the sets of genes that are subject to SL trans-splicing regulation appear to differ between organisms, several commonly shared orthologues were observed. Knockdown of trans-spliced transcripts in sporocysts resulted in a systemic reduction of the expression levels of all tested trans-spliced transcripts; however, the only phenotypic effect observed was diminished larval size. Further studies involving the findings from this work will provide new insights into the role of trans-splicing in the biology of S. mansoni and other organisms. All Expressed Sequence Tags generated in this study were submitted to dbEST as five different libraries. The accessions for each library and for the individual sequences are as follows: (i) adult worms of mixed sexes (LIBEST_027999: JZ139310 - JZ139779), (ii) female adult worms (LIBEST_028000: JZ139780 - JZ140379), (iii) male adult worms (LIBEST_028001: JZ140380 - JZ141002), (iv) eggs (LIBEST_028002: JZ141003 - JZ141497) and (v) schistosomula (LIBEST_028003: JZ141498 - JZ141974).

The identification of two Trypanosoma cruzi I genotypes from domestic and sylvatic transmission cycles in Colombia based on a single polymerase chain reaction amplification of the spliced-leader intergenic region

A single polymerase chain reaction (PCR) reaction targeting the spliced-leader intergenic region of Trypanosoma cruzi I was standardised by amplifying a 231 bp fragment in domestic (TcIDOM) strains or clones and 450 and 550 bp fragments in sylvatic strains or clones. This reaction was validated using 44 blind coded samples and 184 non-coded T. cruzi I clones isolated from sylvatic triatomines and the correspondence between the amplified fragments and their domestic or sylvatic origin was determined. Six of the nine strains isolated from acute cases suspected of oral infection had the sylvatic T. cruzi I profile. These results confirmed that the sylvatic T. cruzi I genotype is linked to cases of oral Chagas disease in Colombia. We therefore propose the use of this novel PCR reaction in strains or clones previously characterised as T. cruziI to distinguish TcIDOMfrom sylvatic genotypes in studies of transmission dynamics, including the verification of population selection within hosts or detection of the frequency of mixed infections by both T. cruzi I genotypes in Colombia.

Inteligência estratégica antecipativa coletiva e crowdfunding: aplicação do método L.E.SCAnning em empresa social de economia peer-to-peer (P2P)

Neste artigo, apresentam-se os resultados de pesquisa qualitativa em que se objetivou investigar a aplicabilidade do método L.E.SCAnning em empresas sociais de economia peer-to-peer (P2P). A motivação partiu da ideia de a autossustentabilidade ser, a longo prazo, um dos maiores desafios das organizações, especialmente aquelas lastreadas na economia social, dentre elas, as empresas P2P. No entanto, empresas sociais são potencialmente negócios dinâmicos e progressistas com os quais o mercado empresarial poderia aprender, uma vez que experimentam e inovam. Partindo exatamente desse espírito inovador, muitas empresas sociais voltaram-se para o modelo crowdfunding de economia P2P, que se configura como tendência emergente de organização colaborativa de recursos na Web. Sob esse prisma, um dos novos desenvolvimentos em gestão que se aplicam à atividade de organizações com enfoque sistêmico é a prática da Inteligência Estratégica Antecipativa Coletiva (IEAc). Nesse sentido, no estudo de caso investigou-se a empresa social francesa Babyloan para compreender de que maneira a organização busca, monitora e utiliza a informação captada do meio externo para sua atuação, prototipando, com base nesse diagnóstico, a aplicação de um ciclo do método L.E.SCAnning. Os resultados deste estudo sugerem que o entendimento pragmático do cenário externo, por meio da IEAc, favorece decisões que trazem uma marca de empreendedorismo e inovação, e tem no universo da economia social P2P, ambiente fortemente baseado em percepção, um impacto potencial significativo.

Adaptation en français et en allemand d'une échelle de pression des pairs pour jeunes adultes : le Peer Pressure Inventory [Adaptation of a peer pressure scale in French and German: the Peer Pressure Inventory].

BACKGROUND: Peer pressure is regarded as an important determinant of substance use, sexual behavior and juvenile delinquency. However, few peer pressure scales are validated, especially in French or German. Little is known about the factor structure of such scales or the kind of scale needed: some scales takes into account both peer pressure to do and peer pressure not to do, while others consider only peer pressure to do. The aim of the present study was to adapt French and German versions of the Peer Pressure Inventory, which is one of the most widely used scales in this field. We considered its factor structure and concurrent validity. METHODS: Five thousand eight hundred and sixty-seven young Swiss men filled in a questionnaire on peer pressure, substance use, and other variables (conformity, involvement) in a cohort study. RESULTS: We identified a four-factor structure, with the three factors of the initial Peer Pressure Inventory (involvement, conformity, misconduct) and adding a new one (relationship with girls). A non-valued scale (from no peer pressure to peer pressure to do only) showed stronger psychometric qualities than a valued scale (from peer pressure not to do to peer pressure to do). Concurrent validity was also good. Each behavior or attitude was significantly associated with peer pressure. CONCLUSION: Peer pressure seems to be a multidimensional concept. In this study, peer pressure to do showed the strongest influence on participants. Indeed, peer pressure not to do did not add anything useful. Only peer pressure to do affected young Swiss men's behaviors and attitudes and was reliable.

Open minded and open access: introducing NeoBiota, a new peer-reviewed journal of biological invasions

The Editorial presents the focus, scope, policies, and the inaugural issue of NeoBiota, a new open access peer-reviewed journal of biological invasions. The new journal NeoBiota is a continuation of the former NEOBIOTA publication series. The journal will deal with all aspects of invasion biology and impose no restrictions on manuscript size neither on use of color. NeoBiota implies an XML-based editorial workflow and several cutting-edge innovations in publishing and dissemination, such as semantic markup of and enhancements to published texts, data publication, and extensive cross-linking within the journal and to external sources

Leader corruption depends on power and testosterone

We used incentivized experimental games to manipulate leader power-the number of followers and the discretion leaders had to enforce their will. Leaders had complete autonomy in deciding payouts to themselves and their followers. Although leaders could make prosocial decisions to benefit the public good they could also abuse their power by invoking antisocial decisions, which reduced the total payouts to the group but increased leader's earnings. In Study 1 (N = 478), we found that both amount of followers and discretionary choices independently predicted leader corruption. In Study 2 (N = 240), we examined how power and individual differences (e.g., personality, hormones) affected leader corruption over time; power interacted with testosterone in predicting corruption, which was highest when leader power and baseline testosterone were both high. Honesty predicted initial level of leader antisocial decisions; however, honesty did not shield leaders from the corruptive effect of power.

CompP2P-GUI : interfície gràfica del Sistema de Computació Distribuïda Peer to Peer (CompP2P)

CompP2P és una interfície gràfica implementada amb Java Swing 1.5 del Sistema de Còmput Distribuït P2P CompP2P. És una interfície gràfica polivalent, és a dir, pot ésser usada en diferents sistemes operatius (Linux, Mac0sX, Windows) i per tant ha d'ésser una aplicació multiplataforma. S'ha aconseguit millorar la gestió de tots els recursos de CompP2P mitjançant una interfície gràfica molt usable i també amb modificacions efectuades en el sistema base CompP2P on s'han afegit i/o millorat aspectes com la comunciació remota, les comandes de gestió del sistema, etc.

Tree-based message diffusion for managing replicated data in unreliable and resource-constrained peer-to-peer environment

Abstract This thesis proposes a set of adaptive broadcast solutions and an adaptive data replication solution to support the deployment of P2P applications. P2P applications are an emerging type of distributed applications that are running on top of P2P networks. Typical P2P applications are video streaming, file sharing, etc. While interesting because they are fully distributed, P2P applications suffer from several deployment problems, due to the nature of the environment on which they perform. Indeed, defining an application on top of a P2P network often means defining an application where peers contribute resources in exchange for their ability to use the P2P application. For example, in P2P file sharing application, while the user is downloading some file, the P2P application is in parallel serving that file to other users. Such peers could have limited hardware resources, e.g., CPU, bandwidth and memory or the end-user could decide to limit the resources it dedicates to the P2P application a priori. In addition, a P2P network is typically emerged into an unreliable environment, where communication links and processes are subject to message losses and crashes, respectively. To support P2P applications, this thesis proposes a set of services that address some underlying constraints related to the nature of P2P networks. The proposed services include a set of adaptive broadcast solutions and an adaptive data replication solution that can be used as the basis of several P2P applications. Our data replication solution permits to increase availability and to reduce the communication overhead. The broadcast solutions aim, at providing a communication substrate encapsulating one of the key communication paradigms used by P2P applications: broadcast. Our broadcast solutions typically aim at offering reliability and scalability to some upper layer, be it an end-to-end P2P application or another system-level layer, such as a data replication layer. Our contributions are organized in a protocol stack made of three layers. In each layer, we propose a set of adaptive protocols that address specific constraints imposed by the environment. Each protocol is evaluated through a set of simulations. The adaptiveness aspect of our solutions relies on the fact that they take into account the constraints of the underlying system in a proactive manner. To model these constraints, we define an environment approximation algorithm allowing us to obtain an approximated view about the system or part of it. This approximated view includes the topology and the components reliability expressed in probabilistic terms. To adapt to the underlying system constraints, the proposed broadcast solutions route messages through tree overlays permitting to maximize the broadcast reliability. Here, the broadcast reliability is expressed as a function of the selected paths reliability and of the use of available resources. These resources are modeled in terms of quotas of messages translating the receiving and sending capacities at each node. To allow a deployment in a large-scale system, we take into account the available memory at processes by limiting the view they have to maintain about the system. Using this partial view, we propose three scalable broadcast algorithms, which are based on a propagation overlay that tends to the global tree overlay and adapts to some constraints of the underlying system. At a higher level, this thesis also proposes a data replication solution that is adaptive both in terms of replica placement and in terms of request routing. At the routing level, this solution takes the unreliability of the environment into account, in order to maximize reliable delivery of requests. At the replica placement level, the dynamically changing origin and frequency of read/write requests are analyzed, in order to define a set of replica that minimizes communication cost.

School Leader Update, September 2004

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School Leader Update, January 1, 2005

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