Structural aspects of dynamic and DNA recognition of HPV-16 E2C protein

L’infezione da Papillomavirus Umano (HPV) è una delle maggiori cause eziologiche del tumore al collo dell'utero e rappresenta un grave problema di salute per le donne in tutto il mondo. La pur sperimentazione di vaccini non ha alcun effetto nel corso di infezione e il sia pur grande sforzo nella profilassi è controbilanciato dalla mancanza di accessibilità per la maggior parte della popolazione. Alla luce di queste considerazioni, non vi è la necessità di sviluppare farmaci antivirali specifici per prevenire le infezioni da HPV. Il mio lavoro di dottorato è stato incentrato sulla aspetti strutturali e funzionali del domonio C-terminale della proteina E2 del ceppo ad alto rischio HPV16 . (E2C) E2C è l'unico fattore di trascrizione codificati dal genoma virale e svolge un ruolo centrale nel controllare l'espressione di tutti i geni virale espressi nel ciclo vitale dell’HPVThe Human Papillomavirus (HPV) infection is linked to cervical cancer and represents a serious problem for women health worldwide .The existence of effective vaccines will not affect the course of infection , in particular those in developing countries and the tremendous prophylactic effect of the vaccine is counterbalanced by the lack of accessibility to most of the population. In view of these considerations, there is a need to develop specific antiviral drugs to prevent HPV infections. My PhD work was focused on the particular properties and structure-functional aspects of the E2 HPV16 DNA binding domain (E2C) E2C is the only transcription factor encoded by the viral genome and plays a central role in controlling the expression of all Papilomavirus genes and in regulating the virus life cycl

Analisi del differenziamento genetico tra popolazioni di Octopus vulgaris Cuvier, 1797 mediante marcatori nucleari e mitocondriali

The common octopus, Octopus vulgaris Cuvier, 1797, represents an important commercial fishery marine resource all over the world, characterized by increasing requests from the markets. In the Mediterranean Sea, especially for the Italian fishery, this species constitutes an important portion of trawling and artisanal landings. In Italy, despite the great socio-economic interest, specific management measures do not exist at the national level for this resource. The common octopus is a very interesting topic both for applied studies and for the basic research, especially at the taxonomic level, because of the uncertainties regarding the occurrence of a single species, with cosmopolitan distribution, or the existence of multiple species forming a ‘species complex’. The principal aim of this work is the genetic characterization of seven populations of O. vulgaris along the coasts of Sardinia in order to obtain useful indications for the selection of correct management units. The genetic analyses have been realized using three different genetic markers, two mitochondrial (the Cytochrome Oxidase I (COI) and III (COIII) genes), and one nuclear marker (five microsatellites loci). All markers proved to be useful in investigating the genetic structure of the populations. In particular, the mitochondrial sequences were useful in comparisons with homologous ones from the GenBank database to evaluate the species’ taxonomy. The results of AMOVA show a substantial homogeneity in Sardinian populations that display low levels of differentiation, both with the nuclear marker (FST=0.004 ns), and the mitochondrial ones (ΦSTCOI=0.003 ns; ΦSTCOIII=0.0002 ns). The pairwise analyses show low levels of differentiation and not significant values for all the genetic markers. The lack of significant genetic differentiation in the Sardinian samples is further confirmed by DAPC, PCA analyses and the Bayesian clustering of the software STRUCTURE. The demography was investigated using all the genetic markers, which pointed out the lack of demographic changes in recent time. The multimodal mismatch distributions reaffirm the occurrence of populations demographically stable. The stability of the populations was confirmed by the haplotype network analyses with the two mitochondrial markers, highlighting a common situation in stationary populations: several principal haplotypes, shared by all the locations, and an increasing number of new secondary haplotypes arising from mutational events. The COI and COIII sequences permitted the comparison of the Sardinian haplotypes with the O. vulgaris sequences available in GenBank. Both markers highlight a genetic affinity among Sardinian specimens and the sequences from the Mediterranean Sea (France, Spain, Central Mediterranean and Turkey), the Eastern Atlantic Ocean (Morocco, Senegal and Galicia), the Southern Atlantic Ocean (South Africa and Tristan da Cunha) and the Southern Indian Ocean (Amsterdam and Saint Paul Islands). This substantial genetic homogeneity contrasts with some sequences (from specimens collected in Turkey, Japan, China, Brazil and Venezuela) that resulted to be highly divergent from all the others. This finding reaffirms the potential existence of several O. vulgaris populations, just partially interconnected, or the even occurrence of distinct species, and emphasizes the need for more detailed phylogeographic and taxonomic studies of the Octopus genus to confirm or exclude the presence of cryptic species within the taxon, as suggested by several authors

Thermal transport in porous Si nanowires from approach-to-equilibrium molecular dynamics calculations

We study thermal transport in porous Si nanowires (SiNWs) by means of approach-to-equilibrium molecular dynamics simulations. We show that the presence of pores greatly reduces the thermal conductivity, κ, of the SiNWs as long mean free path phonons are suppressed. We address explicitly the dependence of κ on different features of the pore topology-such as the porosity and the pore diameter-and on the nanowire (NW) geometry-diameter and length. We use the results of the molecular dynamics calculations to tune an effective model, which is capable of capturing the dependence of κ on porosity and NW diameter. The model illustrates the failure of Matthiessen's rule to describe the coupling between boundary and pore scattering, which we account for by the inclusion of an additional empirical term

Molecular Dynamics Simulations of Thermal Transport in Solid State Systems

In this chapter, we provide a synoptic review of the theoretical/computational approaches currently used to characterize thermal transport at the nanoscale, a topic of paramount importance for several applications and technological thermal management requirements. We focus in particular on the description of the atomistic techniques based on equilibrium (EMD), non-equilibrium (NEMD), and approach to equilibrium (AEMD) molecular dynamics (MD), which allow to efficiently describe relatively large and structurally complex systems with a reduced computational cost as compared to fully "ab-initio" techniques. We describe the theoretical background for each simulation strategy, as well as their implementation in state-of-the-art MD codes by underlying their intrinsic limitations and providing strategies to control some of them. We finally perform a series of benchmark calculations on bulk crystalline silicon by showing that the estimated thermal conductivity is weakly dependent on the specific strategy actually employed, while the overall computational cost is largely dependent on it

Thermal boundary resistance from transient nanocalorimetry: a multiscale modeling approach

The Thermal Boundary Resistance at the interface between a nanosized Al film and an Al_{2}O_{3} substrate is investigated at an atomistic level. A room temperature value of 1.4 m^{2}K/GW is found. The thermal dynamics occurring in time-resolved thermo-reflectance experiments is then modelled via macro-physics equations upon insertion of the materials parameters obtained from atomistic simulations. Electrons and phonons non-equilibrium and spatio-temporal temperatures inhomo- geneities are found to persist up to the nanosecond time scale. These results question the validity of the commonly adopted lumped thermal capacitance model in interpreting transient nanocalorimetry experiments. The strategy adopted in the literature to extract the Thermal Boundary Resistance from transient reflectivity traces is revised at the light of the present findings. The results are of relevance beyond the specific system, the physical picture being general and readily extendable to other heterojunctions.Comment: 12 pages, 8 figure

Introducing the concept of generalized thermal diffusivity to understand coupled heat–charge transport in ionic solutions

A theoretical framework addressing the coupled thermal and charge transport phenomena in ionic solutions is here developed. Starting from the microscopic definitions of thermal and charge currents from Onsager formulation of non-equilibrium thermodynamics, a unique, very general and compact form of the governing differential equation for the evolution of a temperature profile is derived. In particular, the con- cept of generalized thermal diffusivity is introduced to capture the overall effect of the coupling between heat and charge transport in a single phenomenological coefficient as well as to shed light on the non-equivalent situations of concurrent or discordant heat and charge currents. To validate our theoretical framework, an ionic salt solution of NaCl in water is investigated

Onboard Scientific Observers Provide a Realistic Picture of Harvesting and Management Priorities for the Precious Red Coral (Corallium rubrum L.)

Mediterranean red coral Corallium rubrum is considered the most precious coral worldwide. Harvesting activities are performed by licensed scuba divers and managed through the recent pan-Mediterranean management plan issued by General Fisheries Commission for the Mediterranean (GFCM) along with measures locally enacted, imposing limits on licenses, harvesting season, minimum depth of dive, and size. The use of Remotely Operated Vehicles (ROVs) is prohibited, with the only exception being for scientific purposes. Despite measures already in force, the implementation of additional management tools has been recently recommended. This article reports results from the first monitoring campaign on C. rubrum harvesting based on ROVs for seabed exploration and Onboard Scientific Observers (OSOs), carried out from 2012 to 2015 along the coast of Sardinia (Mediterranean Sea—Western basin). More than 450 dives were monitored, confirming how ROV's support eases the scouting of exploitable banks, leading to increases in catches. OSOs reported the collection of colonies below the minimum reference size and catches/dive above limits. Onboard observers collected data also on colony diameter, which is crucial for the estimation of population size structure and exploitation status. OSOs proved to be valid tools in providing additional and reliable information on red coral harvesting, thus deserving to be included among mandatory measures for the sustainable exploitation of red coral in the Mediterranean Sea

New insights on the systematics of echinoids belonging to the family Spatangidae Gray 1825 using a combined approach based on morphology, morphometry, and genetics.

Spatangoids are probably the least resolved group within echinoids, with known topological incongruencies between phylogenies derived from molecular (very scarce) and morphological data. The present work, based on the analysis of 270 specimens of Spatangidae (Echinoidea, Spatangoida) trawled in the Sardinian seas (Western Mediterranean), allowed us to verify the constancy of some characters that we consider to be diagnostic at the genus level —such as the path of the subanal fasciole and the relationship between labrum and adjacent ambulacral plates —and to distinguish two distinct forms within the studied material. Based on morphological characters, morphometrics, and molecular analyses (sequencing of two mitochondrial markers: cytochrome c oxidase subunit1 (COI) and 16S), most of the individuals were classified as morphotype A and attributed to the species Spatangus purpureus, the most common spatangoid in the Mediterranean Sea, while a few corresponded to a different morphotype (B), genetically close to the species Spatangus raschi. Preliminary morphological analyses seemed to indicate that morphotype B specimens from Sardinia are slightly different from S. raschi and from Spatangus subinermis individuals, the second species of the family known to occur in the Mediterranean Sea. On the basis of morpho-structural observations and molecular analyses, comparing Mediterranean living forms with species from other areas (Central Eastern Atlantic, North Sea and neighboring basins, South African Sea, Philippines and Indonesian Archipelago, New Zealand, and Hawaiian Islands), the clear distinction of S. purpureus from several other species classified as Spatangus was confirmed. Based on the morphological and genetic differences, we propose to maintain the genus Spatangus including in it only the type species S. purpureus among the living species and to establish the new genus Propespatagus nov. gen. to include several other species previously classified as Spatangus. The clear distinction among different genera was also detected in fossil forms of Spatangus, Propespatagus nov. gen., and Sardospatangus (†) from the European Oligo-Miocene sedimentary rocks of Germany; the Miocene of Ukraine, Italy, and Spatangoids are probably the least resolved group within echinoids, with known topological incongruencies between phylogenies derived from molecular (very scarce) and morphological data. The present work, based on the analysis of 270 specimens of Spatangidae (Echinoidea, Spatangoida) trawled in the Sardinian seas (Western Mediterranean), allowed us to verify the constancy of some characters that we consider to be diagnostic at the genus level —such as the path of the subanal fasciole and the relationship between labrum and adjacent ambulacral plates —and to distinguish two distinct forms within the studied material. Based on morphological characters, morphometrics, and molecular analyses (sequencing of two mitochondrial markers: cytochrome c oxidase subunit1 (COI) and 16S), most of the individuals were classified as morphotype A and attributed to the species Spatangus purpureus, the most common spatangoid in the Mediterranean Sea, while a few corresponded to a different morphotype (B), genetically close to the species Spatangus raschi. Preliminary morphological analyses seemed to indicate that morphotype B specimens from Sardinia are slightly different from S. raschi and from Spatangus subinermis individuals, the second species of the family known to occur in the Mediterranean Sea. On the basis of morpho-structural observations and molecular analyses, comparing Mediterranean living forms with species from other areas (Central Eastern Atlantic, North Sea and neighboring basins, South African Sea, Philippines and Indonesian Archipelago, New Zealand, and Hawaiian Islands), the clear distinction of S. purpureus from several other species classified as Spatangus was confirmed. Based on the morphological and genetic differences, we propose to maintain the genus Spatangus including in it only the type species S. purpureus among the living species and to establish the new genus Propespatagus nov. gen. to include several other species previously classified as Spatangus. The clear distinction among different genera was also detected in fossil forms of Spatangus, Propespatagus nov. gen., and Sardospatangus (†) from the European Oligo-Miocene sedimentary rocks of Germany; the Miocene of Ukraine, Italy, and Spatangoids are probably the least resolved group within echinoids, with known topological incongruencies between phylogenies derived from molecular (very scarce) and morphological data. The present work, based on the analysis of 270 specimens of Spatangidae (Echinoidea, Spatangoida) trawled in the Sardinian seas (Western Mediterranean), allowed us to verify the constancy of some characters that we consider to be diagnostic at the genus level —such as the path of the subanal fasciole and the relationship between labrum and adjacent ambulacral plates —and to distinguish two distinct forms within the studied material. Based on morphological characters, morphometrics, and molecular analyses (sequencing of two mitochondrial markers: cytochrome c oxidase subunit1 (COI) and 16S), most of the individuals were classified as morphotype A and attributed to the species Spatangus purpureus, the most common spatangoid in the Mediterranean Sea, while a few corresponded to a different morphotype (B), genetically close to the species Spatangus raschi. Preliminary morphological analyses seemed to indicate that morphotype B specimens from Sardinia are slightly different from S. raschi and from Spatangus subinermis individuals, the second species of the family known to occur in the Mediterranean Sea. On the basis of morpho-structural observations and molecular analyses, comparing Mediterranean living forms with species from other areas (Central Eastern Atlantic, North Sea and neighboring basins, South African Sea, Philippines and Indonesian Archipelago, New Zealand, and Hawaiian Islands), the clear distinction of S. purpureus from several other species classified as Spatangus was confirmed. Based on the morphological and genetic differences, we propose to maintain the genus Spatangus including in it only the type species S. purpureus among the living species and to establish the new genus Propespatagus nov. gen. to include several other species previously classified as Spatangus. The clear distinction among different genera was also detected in fossil forms of Spatangus, Propespatagus nov. gen., and Sardospatangus (†) from the European Oligo-Miocene sedimentary rocks of Germany; the Miocene of Ukraine, Italy, and North Africa; the Plio-Pleistocene of Italy; and the Mio-Pliocene of Florida (USA). The new data can help in addressing taxonomic ambiguities within echinoids, as well as in improving species identification, and hence biodiversity assessments in the Mediterranean region

Mendelian breeding units <i>versus</i> standard sampling strategies: mitochondrial DNA variation in southwest Sardinia

We report a sampling strategy based on Mendelian Breeding Units (MBUs), representing an interbreeding group of individuals sharing a common gene pool. The identification of MBUs is crucial for case-control experimental design in association studies. The aim of this work was to evaluate the possible existence of bias in terms of genetic variability and haplogroup frequencies in the MBU sample, due to severe sample selection. In order to reach this goal, the MBU sampling strategy was compared to a standard selection of individuals according to their surname and place of birth. We analysed mitochondrial DNA variation (first hypervariable segment and coding region) in unrelated healthy subjects from two different areas of Sardinia: the area around the town of Cabras and the western Campidano area. No statistically significant differences were observed when the two sampling methods were compared, indicating that the stringent sample selection needed to establish a MBU does not alter original genetic variability and haplogroup distribution. Therefore, the MBU sampling strategy can be considered a useful tool in association studies of complex traits