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Canine distemper virus (CDV) is the etiologic agent of distemper in dogs. It exhibits an elevated potential of crossing species barriers, infecting a wide range of wild and domestic carnivores. Of its encoding genes, hemagglutinin (H) shows high heterogeneity, and it was used to determine the relationship between CDV strains due to its variability and key role in determining cell tropism, host shift, and in eliciting a protective immune response. This study analysed the full-length H gene sequence of Arctic-like CDV strains collected from dogs in Italy during a period in which an increased activity of CDV diffusion was observed. The common amino acid changes and features of Arctic-like CDV strains collected from 2011 to 2016 in Europe were described, providing an updated analysis of the genomic features. A comparison with CDV vaccine strains was carried out to evaluate the increased genomic difference with CDV Arctic-like field strains. This study provides a complete and updated analysis of the current spreading strains of Arctic-like lineage and the main amino acid variations in the hemagglutinin gene sequence circulating in Italy. Moreover, it provides novel information regarding the evolution of the most recent CDV Arctic-like lineage strains collected in Europe.

Light absorption can trigger biologically relevant protein conformational changes. The light-induced structural rearrangement at the level of a photoexcited chromophore is known to occur in the femtosecond timescale and is expected to propagate through the protein as a quake-like intramolecular motion. Here we report direct experimental evidence of such ‘proteinquake’ observed in myoglobin through femtosecond X-ray solution scattering measurements performed at the Linac Coherent Light Source X-ray free-electron laser. An ultrafast increase of myoglobin radius of gyration occurs within 1 picosecond and is followed by a delayed protein expansion. As the system approaches equilibrium it undergoes damped oscillations with a ~3.6-picosecond time period. Our results unambiguously show how initially localized chemical changes can propagate at the level of the global protein conformation in the picosecond timescale., Localized chemical events such as the breakage of a bond between a protein and a ligand may trigger a global protein conformational change. Here, the authors use an X-ray free-electron laser to track the motion of myoglobin in response to photoinduced ligand release, and observe a picosecond proteinquake.

In this work, we compare experimental data on myoglobin hydrated powders from elastic neutron scattering, broadband dielectric spectroscopy, and differential scanning calorimetry. Our aim is to obtain new insights on the connection between the protein dynamical transition, a fundamental phenomenon observed in proteins whose physical origin is highly debated, and the liquid-liquid phase transition (LLPT) possibly occurring in protein hydration water and related to the existence of a low temperature critical point in supercooled water. Our results provide a consistent thermodynamic/dynamic description which gives experimental support to the LLPT hypothesis and further reveals how fundamental properties of water and proteins are tightly related.

Il poster presenta gli esiti della ricerca archeologica nella catacomba paleocristiana di Villagrazia di Carini negli anni 2008-2010. Alla rimozione degli strati di interro alluvionale, che ingombravano i settori indagati (gallerie VII-X e cubicolo X.20), si è affiancata l'analisi delle consistenze architettoniche, che ha consentito di delineare le diverse fasi della frequentazione per uso funerario. Ulteriori interessanti dati sono emersi dall'analisi dei resti osteologici e dalle operazioni di pulitura delle pareti dagli strati fangosi, che ha riportato alla luce nuovi apparati decorativi pittorici. The text introduces the results of the archaeological excavations carried out during the years 2008-2010 in the Christian catacomb of Villagrazia di Carini by the University of Palermo (scientific direction Prof. R.M. Carra, in agreement with the Pontificia Commissione di Archeologia Sacra. The interventions have regarded the galleries GVII, whose floor has been reached; GVIII, where the floor with its formae has entirely brought to light; GIX, object of a careful revision after the investigation of the wall tombs; and GX, where has been started the exploration of the wide cubicle X.20

Dati di scavo, analisi strutturale e degli apparati pittorici dei cubicoli al momento più rappresentativi della catacomba.

Le “somiglianze” tra antico e presente rituale non sono né accidentali né, necessariamente, frutto dell’adozione di certi modelli “forti” derivati da contatti culturali. Sono, piuttosto, specifici atti di parole, costruiti a partire da una langue simbolica comune (un apparato simbolico, sostanziato di credenze con valore cognitivo, diretto a riempire di senso i discreta culturalmente estrapolati dalla “realtà”) formatasi al momento dell’affermarsi dei regimi di vita neolitici. L’emergere, al momento del passaggio a un’economia agricola e a forme di insediamento stabili, di nuovi problemi socio-ecologici aveva imposto all’uomo, infatti, l’adozione di nuove configurazioni simboliche che organizzavano insieme, coerentemente, simboli derivati dalle nuove esigenze produttive con modelli formali e associazioni figurative già note, come, per. es., nel caso delle figurazioni del divino femminile nel passaggio dal paleolitico al neolitico. Tutto questo mette in evidenza come l’organizzazione dei calendari cerimoniali, i sistemi di credenze e le forme rituali delle civiltà agro-pastorali, più o meno condizionati da esigenze sociali e politiche, dimostrino sempre e comunque una originaria dipendenza da alcune istanze comuni che si sono tradotte in un circoscritto vocabolario, in un coerente insieme di simboli rituali. Tali considerazioni trovano conferma nell’esame del simbolismo rituale di diversi contesti festivi che vedono come protagonista San Calogero, santo il cui culto è in Sicilia evidentemente connesso alle attività agricole e, segnatamente, cerealicole. The "similarities" between ancient and present ritual are neither accidental nor, necessarily, the result of the adoption of certain "strong" models derived from cultural contacts. Rather, they are specific acts of words, constructed starting from a common symbolic langue (a symbolic apparatus, substantiated by beliefs with cognitive value, aimed at filling with meaning the discretes culturally extrapolated from "reality") formed at the moment of the affirmation of Neolithic life regimes. The emergence, at the time of the transition to an agricultural economy and stable forms of settlement, of new socio-ecological problems had in fact forced man to adopt new symbolic configurations which coherently organized together symbols derived from the new production needs with formal models and figurative associations already known, such as, per. eg, in the case of the depictions of the divine feminine in the transition from the Paleolithic to the Neolithic. All this highlights how the organization of ceremonial calendars, belief systems and ritual forms of agro-pastoral civilizations, more or less conditioned by social and political needs, always demonstrate an original dependence on some common instances they are translated into a circumscribed vocabulary, into a coherent set of ritual symbols. These considerations are confirmed in the examination of the ritual symbolism of various festive contexts that see as the protagonist San Calogero, a saint whose cult in Sicily is evidently connected to agricultural and, in particular, cereal activities.

The brain has a limited process of repair/regeneration linked to the restricted and localized activity of neuronal stem cells. Consequently, it shows a reduced capacity to counteract the age-related loss of neural and glial cells and to repair the consequent injuries/lesions of nervous system. This progressively determines nervous dysfunction and onset/progression of neurodegenerative diseases, which represent a serious social (and economic) problem of our populations. Thus, the research of efficient treatments is encouraged. Stem cell therapy might represent a solution. Today, it, indeed, represents the object of intensive research with the hope of using it, in a near future, as effective therapy for these diseases and preventive treatment in susceptible individuals. Here, we report and discuss the data of the recent studies on this field, underling the obstacles and benefits. We also illustrate alternative measures of intervention, which represent another parallel aim for the care of neurodegenerative pathology-affected individuals. Thus, the road for delaying or retarding these diseases appears hard and long, but the advances might be different.

International audience; — Proteins, the nano-machines of living systems, are highly dynamic molecules. The timescale of functionally relevant motions spans over a very broad range, from femtoseconds to several seconds. In particular, the pico-to nanoseconds region is characterized by side-chain and backbone anharmonic fluctuations that are responsible for many biological tasks like ligand binding, substrate recognition and enzymatic activity. Neutron scattering on hydrated protein powders reveals two main activations of anharmonic dynamics, characterized by different onset temperature and amplitude. Here we review our work on synthetic polypeptides, native proteins, and single amino acids to identify the physical origin of the two onsets —one involving water-independent local dynamics of methyl groups and, to a minor extent, of aromatic side-chains, and the other one, known as " protein dynamical transition " , concerning large scale functional protein fluctuations, most likely induced by a crossover in the structure and dynamics of hydration water connected with the second critical point hypothesis.

International audience; Amyloid and amyloid-like fibrils are a general class of protein aggregates and represent a central topic in life sciences for their involvement in several neurodegenerative disorders and their unique mechanical and supramolecular morphological properties. Both their biological role and their physical properties, including their high mechanical stability and thermodynamic inertia, are related to the structural arrangement of proteins in the aggregates at molecular level. Significant variations may exist in the supramolecular organization of the commonly termed cross-β structure that constitutes the amyloid core. In this context, a fine knowledge of the structural details in fibrils may give significant information on the assembly process and on possible ways of tuning or inhibiting it. Here we propose a simple method based on the combined use of Fourier transform infrared spectroscopy and Fourier transform Raman spectroscopy to accurately reveal structural details in the fibrillar aggregates, side-chain exposure and intermolecular interactions. Interestingly, coupled analysis of mid-infrared spectra reveals antiparallel β-sheet orientation in ConA fibrils. We also report the comparison between THz absorption spectra of Concanavalin A in its native and fibrillar state at different hydration levels, allowing obtaining corroboration of peaks assignation in this range and information on the effect of amyloid supramolecular arrangement on the network dynamics of hydration water.

International audience; We report time-resolved X-ray absorption measurements after photolysis of carbonmonoxy myoglobin performed at the LCLS X-ray free electron laser with nearly 100 fs (FWHM) time resolution. Data at the Fe K-edge reveal that the photoinduced structural changes at the heme occur in two steps, with a faster (∼70 fs) relaxation preceding a slower (∼400 fs) one. We tentatively attribute the first relaxation to a structural rearrangement induced by photolysis involving essentially only the heme chromophore and the second relaxation to a residual Fe motion out of the heme plane that is coupled to the displacement of myoglobin F-helix

International audience; The Boson peak of deeply cooled water confined in the pores of a silica xerogel is studied by inelastic neutron scattering at different hydration levels to separate the contributions from matrix, water on the pore surfaces and "internal" water. Our results reveal that at high hydration level, where the contribution from internal water is dominant, the temperature dependence of the Boson peak intensity shows an inflection point at about 225 K. The complementary use of differential scanning calorimetry to describe the thermodynamics of the system allows identifying the inflection point as the signature of a water liquid-liquid crossover.

International audience; In this work we investigate, by means of elastic neutron scattering, the pressure dependence of mean square displacements (MSD) of hydrogen atoms of deeply cooled water confined in the pores of a three-dimensional disordered SiO 2 xerogel; experiments have been performed at 250 and 210 K from atmospheric pressure to 1200 bar. The " pressure anomaly " of supercooled water (i.e., a mean square displacement increase with increasing pressure) is observed in our sample at both temperatures; however, contrary to previous simulation results and to the experimental trend observed in bulk water, the pressure effect is smaller at lower (210 K) than at higher (250 K) temperature. Elastic neutron scattering results are complemented by differential scanning calorimetry data that put in evidence, besides the glass transition at about 170 K, a first-order-like endothermic transition occurring at about 230 K that, in view of the neutron scattering results, can be attributed to a liquid-liquid crossover. Our results give experimental evidence for the presence, in deeply cooled confined water, of a crossover occurring at about 230 K (at ambient pressure) from a liquid phase predominant at 210 K to another liquid phase predominant at 250 K; therefore, they are fully consistent with the liquid-liquid transition hypothesis.

A silica xerogel can be obtained from an alcoxide precursor (TMOS, tetramethylortosilcate) via the sol-gel method: TMOS hydrolysis and subsequent polycondensation yields a solid, disordered, porous SiO2 matrix (average pore dimensions ~20Å). Inside the pores water is trapped and the hydration level h=gr[H2O]/gr[SiO2] can be easily controlled. The presence and temperature dependence of the boson peak (BP) in xerogel confined supercooled water was studied with inelastic neutron scattering (spectrometer IN6 at ILL, Grenoble) in xerogel samples having h=0.4 and h=0.2. After careful subtraction of the contributions arising from the matrix and from quasi-elastic scattering, the BP contribution was analysed in terms of a log-normal distribution to obtain the excess density of states (DOS). A clear inversion in the temperature dependence of the peak height of the excess DOS was observed at about 225K, the same temperature as the proposed LDL->HDL transition in supercooled water. The pressure dependence of mean square displacements (MSD) was investigated, in the same samples, with elastic neutron scattering (spectrometer IN13, at ILL,Grenoble), exploiting the high pressure cell developed by J. Peters and collaborators. At 250K, a marked MSD increase with pressure was observed, in agreement with the well known “anomaly” of supercooled water and with previous experimental results. However, at 210K the pressure effect was much lower, again in agreement with the presence of an LDL->HDL transition in supercooled water. Finally, the relevance of the above results to protein dynamics and in particular to the “protein dynamical transition” will also be discussed.

Trapping of organic molecules and dyes within nanoporous matrices is of great interest for the potential creation of new materials with tailored features and, thus, different possible applications ranging from nanomedicine to material science. The understanding of the physical basis of entrapment and the spectral properties of the guest molecules within the host matrix is an essential prerequisite for the design and control of the properties of these materials. In this work, we show that a mesoporous silica xerogel can efficiently trap the dye thioflavin T (ThT, a molecule used as a marker of amyloid fibrils and with potential drug benefits), sequestering it from an aqueous solution and producing a highly fluorescent material with a ThT quantum yield 1500 times greater than that of the free molecule. The study of spectroscopical properties of this system and the comparison with fluorescence of an uncharged analogue of ThT give indications about the mechanism responsible for the fluorescence switching-on of ThT molecules during their uptaking into the glass. Diffusion and nanocapillarity are responsible for ThT absorption, whereas electrostatic interaction between positive ThT molecules and negative dangling SiO groups covering the pore surfaces causes the immobilization of ThT molecules inside the pores and the enhancement of its fluorescence, in line with the molecular rotor model proposed for this dye. We also show that entrapment efficiency and kinetics can be tuned by varying the electrostatic properties of the dye and/or the matrix. © 2013 American Chemical Society.