PARASITOLOGICAL ZOONOSIS IN RABBIT MEAT: RESULTS OF SEROEPIDEMIOLOGICAL SURVEY FOR THE INVESTIGATION OF ENCEPHALITOZOON CUNICULI, TOXOPLASMA GONDII AND CHLAMYDIA PSITTACI IN ITALIAN RABBITRIES

ABSTRACT During June 2002 and February 2003 1,800 blood samples were collected from 5 slaughtering plants located in Campania region (Italy) which were supplied by 21 rabbitries situated in central and southern Italian regions, such as Campania, Lazio, Basilicata, Molise, Calabria. The aims of this study were to use the Carbon Immunoassay (India ink) test (CIA) and FC test to determine respectively the prevalence of specific zoonotic agents such as E. cuniculi, T. gondii and Chlamydia psittaci in fattening rabbits. For E. cuniculi of the total number of 1,800 sera examined, 490 were positive and they represented 27.2%. All supplying breeding farms were positive with a percentage from 10% (4/40) to 57.5% (23/40) of total sera collected from each slaughtered batch. Sera resulted less positive for T. gondii: of 1,800 sera only 50 (2.7%) were positive; these date were relative to 6/21 breeding farms. Serological Chlamydia screening resulted totally negative

Hi-C-constrained physical models of human chromosomes recover functionally-related properties of genome organization

Combining genome-wide structural models with phenomenological data is at the forefront of efforts to understand the organizational principles regulating the human genome. Here, we use chromosome-chromosome contact data as knowledge-based constraints for large-scale three-dimensional models of the human diploid genome. The resulting models remain minimally entangled and acquire several functional features that are observed in vivo and that were never used as input for the model. We find, for instance, that gene-rich, active regions are drawn towards the nuclear center, while gene poor and lamina associated domains are pushed to the periphery. These and other properties persist upon adding local contact constraints, suggesting their compatibility with non-local constraints for the genome organization. The results show that suitable combinations of data analysis and physical modelling can expose the unexpectedly rich functionally-related properties implicit in chromosome-chromosome contact data. Specific directions are suggested for further developments based on combining experimental data analysis and genomic structural modelling

Chromatin-Driven Behavior of Topologically Associating Domains

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PRC2 controls Drosophila oocyte cell fate by repressing cell cycle genes

The oocyte is a unique cell type that undergoes extensive chromosome changes on its way to fertilization, but the chromatin determinants of its fate are unknown. Here, we show that Polycomb group (PcG) proteins of the Polycomb repressive complex 2 (PRC2) determine the fate of the oocyte in Drosophila. Mutation of the enzymatic PRC2 subunit Enhancer of zeste (E(z)) in the germline abolishes spatial and temporal control of the cell cycle and induces sterility via transdetermination of the oocyte into a nurse-like cell. This fate switch depends on loss of silencing of two PRC2 target genes, Cyclin E and the cyclin-dependent kinase inhibitor dacapo. By contrast, the PRC1 component Polycomb (Pc) plays no role in this process. Our results demonstrate that PRC2 plays an exquisite role in the determination of the oocyte fate by preventing its switching into an endoreplicative program

Stable Polycomb-dependent transgenerational inheritance of chromatin states in Drosophila

International audienceTransgenerational epigenetic inheritance (TEI) describes the transmission of alternative functional states through multiple generations in the presence of the same genomic DNA sequence. Very little is known about the principles and the molecular mechanisms governing this type of inheritance. Here, by transiently enhancing 3D chromatin interactions, we established stable and isogenic Drosophila epilines that carry alternative epialleles, as defined by differential levels of Polycomb-dependent trimethylation of histone H3 Lys27 (forming H3K27me3). After being established, epialleles can be dominantly transmitted to naive flies and can induce paramutation. Importantly, epilines can be reset to a naive state by disruption of chromatin interactions. Finally, we found that environmental changes modulate the expressivity of the epialleles, and we extended our paradigm to naturally occurring phenotypes. Our work sheds light on how nuclear organization and Polycomb group (PcG) proteins contribute to epigenetically inheritable phenotypic variability