Sapienza University of Rome

About: Sapienza University of Rome is a education organization based out in Rome, Lazio, Italy. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 62002 authors who have published 155468 publications receiving 4397244 citations. The organization is also known as: La Sapienza & Università La Sapienza di Roma.

IFN-α inhibits HBV transcription and replication in cell culture and in humanized mice by targeting the epigenetic regulation of the nuclear cccDNA minichromosome

Abstract: HBV infection remains a leading cause of death worldwide. IFN-α inhibits viral replication in vitro and in vivo, and pegylated IFN-α is a commonly administered treatment for individuals infected with HBV. The HBV genome contains a typical IFN-stimulated response element (ISRE), but the molecular mechanisms by which IFN-α suppresses HBV replication have not been established in relevant experimental systems. Here, we show that IFN-α inhibits HBV replication by decreasing the transcription of pregenomic RNA (pgRNA) and subgenomic RNA from the HBV covalently closed circular DNA (cccDNA) minichromosome, both in cultured cells in which HBV is replicating and in mice whose livers have been repopulated with human hepatocytes and infected with HBV. Administration of IFN-α resulted in cccDNA-bound histone hypoacetylation as well as active recruitment to the cccDNA of transcriptional corepressors. IFN-α treatment also reduced binding of the STAT1 and STAT2 transcription factors to active cccDNA. The inhibitory activity of IFN-α was linked to the IRSE, as IRSE-mutant HBV transcribed less pgRNA and could not be repressed by IFN-α treatment. Our results identify a molecular mechanism whereby IFN-α mediates epigenetic repression of HBV cccDNA transcriptional activity, which may assist in the development of novel effective therapeutics.

Innovation, Diversity and Diffusion: A Self-Organisation Model

Abstract: A number of features of innovation diffusion are identified: appropriability, diversity, expectations, selection, learning, and spillover externalities. A dynamic model is formul ated to embed the diffusion question into a more general framework of disequilibrium competition. The model incorporates distinct vintage structures reflecting a change in technological trajectory, learning-by-using, a nd expectations-driven investment rules of thumb. Simulation studies reveal robust quasi-logistic curves, but a complicated pattern of net market share gains and losses. Uncertainty regarding the rationality of early or late adoption, it is argued, ensures that the requisite behavioral variety is present to generate these diffusion patterns. Copyright 1988 by Royal Economic Society.

Tradeoffs of different types of species occurrence data for use in systematic conservation planning.

Abstract: Data on the occurrence of species are widely used to inform the design of reserve networks. These data contain commission errors (when a species is mistakenly thought to be present) and omission errors (when a species is mistakenly thought to be absent), and the rates of the two types of error are inversely related. Point locality data can minimize commission errors, but those obtained from museum collections are generally sparse, suffer from substantial spatial bias and contain large omission errors. Geographic ranges generate large commission errors because they assume homogenous species distributions. Predicted distribution data make explicit inferences on species occurrence and their commission and omission errors depend on model structure, on the omission of variables that determine species distribution and on data resolution. Omission errors lead to identifying networks of areas for conservation action that are smaller than required and centred on known species occurrences, thus affecting the comprehensiveness, representativeness and efficiency of selected areas. Commission errors lead to selecting areas not relevant to conservation, thus affecting the representativeness and adequacy of reserve networks. Conservation plans should include an estimation of commission and omission errors in underlying species data and explicitly use this information to influence conservation planning outcomes.