ligation overcomes terminal underrepresentation in multiple displacement amplification of linear dna

The amount of DNA available for informative genomic studies is often limiting. Thus, several methods have been developed to achieve a whole genome amplification (WGA). Particu-larly promising is a variant, called multiple displacement amplification (MDA) (1,2), which exploits the high processivity of Φ29 phage DNA polymerase and suffers an amplifi-cation bias significantly lower than previous, PCR-based WGA (3).Even though MDA-DNA has been successfully used for many applica-tions (1,4–7), some problems have been reported. For example, sequences near the ends of linear chromosomes appear underrepresented after MDA (6,8,9). Both defective priming events and abortive chain terminations could contribute to this problem, which limits the applications of MDA and jeopardizes its use on short linear DNA (e.g., cDNA and degraded genomes from forensic, archeological, and fetal origin) (10). In these cases, the terminal underrepresentation would cause the loss of substantial information.We studied this problem using λ phage DNA (48.5 kb; Promega Biosciences, San Luis Obispo, CA, USA). MDA was performed using the Genomiph

Valori, scienza e trascendenza. Volume II - Un dibattito sulla dimensione etica e religiosa nella comunità scientifica internazionale

Scienziati, filosofi e sociologi a confronto sulla ricerca scientifica. Un dibattito tra alcune delle massime personalità della scienza sul metodo, il fondamento etico e il richiamo a un "senso ultimo delle cose" di chi opera alle frontiere della conoscenza.- Indice #5- Prefazione, Marcello Pacini #11- Introduzione Le frontiere della conoscenza scientifica e l'ipotesi del trascendente, Evandro Agazzi #13- Prima parte Sistemi di riferimento e modelli di realtà #25- Moralità e scienza, Sebastiano Maffettone #27- Dal “miracolo europeo” nasce la scienza moderna. La libertà come condizione per il successo economico e per il progresso scientifico, Gerard Radnitzky #39- Tra valori e conoscenza: il dibattito sull’etica della professione scientifica, Rita Levi Montalcini #59- Modelli della scienza e modelli sociali, Giovanni M. Prosperi #63- Manipolazioni genetiche e loro regolamentazione, Vittorio Sgaramella #71- Scienza e culture filosofiche, Gualtiero Pisent #81- Scienza, ontologia, etica, Gianni Vattimo #95- Seconda Parte Conoscenza e scienze empiriche #103- Che cosa sono le leggi di natura?, Paul Davies #105- Le tradizioni nell’impresa scientifica e nella democrazia, Giulio Giorello #129- Verità senza certezze, Francesco Barone #139- Modelli di interazione tra le scienze naturali e le scienze umane e sociali, Luciano Gallino #145- Ai confini della fisica Bianca e Francesco Melchiorri #177- I limiti della fisica, Alfredo Molinari #181- Terza Parte I confini fra scienza e trascendenza #189- Scienza e fede: la ricerca della verità, Paul Poupard #191- Cultura religiosa e cultura degli scienziati, Enrico di Rovasenda #195- Un punto di vista islamico, Abdus Salam #217- L’assoluto che ci sta accanto. Riflessioni sulla trascendenza umana alla luce degli studi odierni sulla conoscenza, Francisco J. Varela #237- Il mistero dell’esistenza umana, John C. Eccles #249- I rapporti tra scienza e trascendenza, Henry Atlan #26

Retrotransposons and siRNA have a role in the evolutionof desiccation tolerance leading to resurrection of the plantCraterostigma plantagineumTobias

\u2022 Craterostigma plantagineum can lose up to 96% of its water content but fully recover within hours after rehydration. The callus tissue of the plant becomes desiccation tolerant upon pre-incubation with abscisic acid (ABA). In callus and vegetative organs, ABA addition and water depletion induce a set of dehydrationresponsive genes. \u2022 Previously, activation tagging led to the isolation of Craterostigma desiccation tolerant (CDT-1), a dehydration-related ABA-inducible gene which renders callus desiccation tolerant without ABA pre-treatment. This gene belongs to a family of retroelements, members of which are inducible by dehydration. \u2022 Craterostigma plantagineum transformation with mutated versions of CDT-1 indicated that protein is not required for the induction of callus desiccation tolerance. Northern analysis and protoplast transfection indicated that CDT-1 directs the synthesis of a double-stranded 21-bp short interfering RNA (siRNA), which opens the metabolic pathway for desiccation tolerance. \u2022 Via transposition, these retroelements have progressively increased the capacity of the species to synthesize siRNA and thus recover after dehydration. This may be a case of evolution towards the acquisition of a new trait, stimulated by the environment acting directly on intra-genomic DNA replication