1,354,198 research outputs found
Marine environment and human health: a whole genomic analysis and evaluation of the pathogenic potential of V.parahaemolyticus strains isolated from Northern Italian seawaters and carrying virulence genes
No full textL’insorgenza di epidemie legate all’ambiente marino sembra esser un fenomeno mondiale in aumento ed un numero crescente di infezioni batteriche umane è stato associato ad aree ricreazionali e legate all’uso commerciale di risorse marine. A causa dell’aumentata dipendenza umana dall’ambiente marino per la pesca, l’acquacoltura, dispositivi di scarico, la potenziale emergenza di patogeni dall’ambiente marino deve esser investigata. Una particolare sfida è costituita dalla potenziale espansione di patogeni marini esistenti nel mare e l’emergenza di nuovi patogeni derivati da ceppi marini autoctoni che hanno acquisito nuovi tratti virulenti via trasferimento genico orizzontale. Alcuni esempi sono l’aumentato consumo di prodotti marini, la comparsa edil diffondersi mondiale di nuovi ceppi di V.parahaemolyticus con potenziale pandemico, e negli ultimi anni alcuni casi di infezioni umane da ceppi di Vibrio species non patogeni.
Lo scopo di questa tesi è stato di comparare ceppi di V.parahaemolyticus ambientali e clinici dal punto di vista genetico e di valutare il potenziale patogeno dei ceppi ambientali.
I ceppi batterici, profondamente studiati nel corso della tesi di Dottorato, sono stati isolati dal Mar Nord Adriatico nel contesto del progetto internazionale “VibrioSea Project”, che aveva come obiettivo quello di sviluppare un sistema di allerta precoce per predire e prevenire le malattie a trasmissione idrica nel Mare Mediterraneo.
La collezione di ceppi ambientali di V.parahaemolyticus è stata caratterizzata tramite una genotipizzazione molecolare per investigare se ceppi isolati nei differenti siti geografici o nei vari periodi dell’anno fossero correlati geneticamente e se fosse possibile identificare cloni persistenti nel tempo o in un sito geografico. Considerando globalmente i dati ottenuti con i 4 metodi di tipizzazione molecolari (ribotyping, PFGE, REP-PCR and ERIC-PCR), e sierotipizzazione, è stato possibile identificare alcuni clusters genetici persistenti in un’area anche per alcuni periodi lunghi. Al contrario non si è potuta stabilire la correlazione tra il tipo di campione o un sito geografico e specifici pattern genici. Il contemporaneo uso di differenti metodi di genotipizzazione si è rivelato essere un approccio efficace permettendo il raggruppamento in ceppi correlati geneticamente e, discriminando, sulla base di piccole differenze, batteri presentanti profili genici molto simili.
Nella seconda parte dello studio è stato valutato il potenziale patogeno dei ceppi ambientali adottando un approccio genomico, sia utilizzando il metodo standard della PCR che un metodo computazionale innovativo, Insignia, che ha permesso il rilevamento di una serie di ceppi ambientali che presentano nel genoma un’siola di patogenicità, includendo diversi geni associati all virulenza. Successivamente l’analisi in vitro della capacità di alcuni ceppi ambientali rappresentativi di aderire e causare danno cellulare a cellule eucarioti ha confermato la patogenicità di ceppi marini.
Sulla base dei dati ottenuti emerge che l’ambiente marino rappresenta un serbatoio di batteri portanti geni di virulenza costituendo così un problema di salute pubblica ed un rischio per la salute umana.Disease outbreaks related to the marine environment appear to be escalating worldwide and growing number of human bacterial infections have been associated with recreational areas and commercial uses of marines resources. Because of the increasing human dependence on marine environments for fisheries, aquaculture, waste disposal and recreation, the potential for pathogen emergence from ocean ecosystems requires investigation.
Particular challenge are the potential expansion of existing-marine indigenous pathogens and the emergence of new pathogens derived from autochthonous marine strains which have acquired new virulence traits via horizontal genetic transfer. The increasing consume of marine food products, the appearance and worldwide spread of new clones of Vibrio parahaemolyticus with pandemic potential and reporting, in very recent years, of some human infection cases caused by non pathogenic vibrios species, are some examples.
The scope of this study has been to compare environmental and clinical Vibrio parahaemolyticus strains from the genetic point of view and to evaluate the pathogenic potential of the environmental strains.
The bacterial strains deeply studied in this doctoral thesis were isolated from the Northern Adriatic Sea in the context of the international VibrioSea Project, aimed to develop a satellite-based early warning system to predict and prevent water-borne diseases in the Mediterranean Sea.
The environmental V. parahaemolyticus strain collection was characterized performing a molecular genotyping to investigate whether the strains isolated in different geographical sites or in different periods of the year were clonally related and if it would be possible to identify clones persisting in time and/or different geographic sites. Considering globally the results obtained with 4 molecular typing methods (ribotyping, PFGE, REP-PCR and ERIC-PCR) and serotyping it has been possible to identify a number of bacterial genetic clusters persisting in the area also for long periods of time. On the contrary, a correlation between the type of sample or a geographic site and specific genetic patterns, has not been established. The contemporary use of different genotyping methods proved to be an effective approach allowing the grouping of genetically related strains also discriminating, on the basis of small differences, bacteria presenting very similar genetic profiles.
In the second part of the study, the pathogenic potential of the environmental strains was evaluated adopting a genomic approach applying standard protocols, such as PCR, but also the innovative computational method Insignia which enabled the detection of a series of environmental strains carrying a pathogenicity island including several virulence-related genes. The subsequent in vitro analysis of the ability of representative environmental strains to adhere to and to cause cell damage in eukaryotic cells confirmed the pathogenic capability of the marine strains.
On the basis of the data obtained it emerges that the marine environment represents a reservoir of bacteria carrying virulence genes thus constituting a public health concern and a risk to human health
Struttura, ideologia e psicologia del doppio nella narrativa dannunziana da Il Piacere a Il Compagno dagli occhi senza cigli
No full textSedimentary processes and glacial cycles on the sediment drifts of the Antarctic Peninsula pacific margin: preliminary results of SEDANO-II Project.
No full textArturo Rietti e il suo tempo : convegno di studi a centocinquant'anni dalla nascita; Trieste, Palazzo Economo, Salone Piemontese 17-18 ottobre 2013
No full textPolar marine diatoms: key markers for Cenozoic environmental shifts. Sedimentary and paleo-environmental reports from Antarctic continental margin (Ross Sea, Wilkes Land and Prydz Bay)
No full textMarine diatoms are sensitive to water-mass distribution and their physical-chemical and biotic preferences affect their
biogeographical distribution. In sedimentary records, although altered by secondary processes such as dissolution, they
track the primary signal formed in surface water. This make them the major biostratigraphic and environmental markers
in the Southern Ocean as they record sea-surface temperatures, sea ice and other parameters usefull for
paleoceanographic and paleoclimatic reconstructions (Jordan et al. 2010; Leventer et al., 2010; Crosta, 2011; Escutia et
al., 2011). We present three case studies of diatom biostratigrapy and paleoceanographic reconstructions performed on
Antarctic sediments recovered from: 1) Pleistocene-Holocene sequences in the Ross Sea and Wilkes Lands, with
evidences of glacial/deglacial-interglacial phases (PNRA and IMAGES-CADO Projects in Atlantic and Australian
Sectors) (Caburlotto et al., 2010; Tolotti et al., 2013) and 2) Late Eocene-Early Miocene sequences in Prydz Bay, with
preliminary micropaleontological results and biostratigraphy related to the greenhouse/ice-house transition (ODP
Project in the Indian Sector) (Lagabrielle et al., 2009; Suto et al., 2012).
Jordan W.J. & Stikley C.E. 2010. Diatoms as indicators of paleoceanographic events. In: Smol J.P. & Stoermer E.F.
Eds., The Diatoms: Applications for the Environmental and Earth Sciences., II Edition., 424-452.
Escutia C., Brinkhuis H., Klaus A. & IODP Expedition 318 Scientists. 2011. IODP Expedition 318: From Greenhouse
to Icehouse at the Wilkes Land Antarctic Margin. Scientific Drilling, 12, 15-23.
Caburlotto A., Lucchi R.G., De Santis L., Macrì P. & Tolotti R. 2010. Sedimentary processes on the Wilkes Land
continental rise reflect changes in glacial dynamic and bottom water flow. International Journal of Earth Sciences,
99(4), 909 – 926.
Crosta X. 2011. Marine diatoms in polar and sub-polar environments and their application to Late Pleistocene
paleoclimate reconstruction. IOP Conf. Series: Earth and Environmental Science, 14, 1-18.
Leventer A., Crosta X. & Pike J. 2010. Holocene marine diatom records of environmental change. In: Smol J.P. and
Stoermer E. F. Eds., II Edition., 401-423.
Lagabrielle Y., Goddéris Y., Donnadieu Y., Malavieille J. & Suarez M. 2009. The tectonic history of Drake Passage
and its possible impacts on global climate. Earth and Planetary Science Letters, 279, 197–211.
Suto I., Kawamura K., Hagimoto S., Teraishi A. & Tanaka Y. 2012. Changes in upwelling mechanisms drove the
evolution of marine organisms. Palaeogeography, Palaeoclimatology, Palaeoecology, 339-341, 39–51.
Tolotti R., Salvi C., Salvi G. & Bonci M.C. 2013. Late Quaternary climate variability as recorded by
micropalaeontological diatom data and geochemical data in the western Ross Sea, Antarctica. Antarctic Science, 25(6),
804–820
Antarctic Bottom Water flow pathway inferred from geomorphology and seismic stratigraphy of the George V Land margin.
No full textSwath bathymetry and seismic reflection profiles collected by the Italian Antarctic Program (PNRA WEGA and
MOGAM projects), combined with Australian (CSIRO) oceanographic measures (Williams et al., 2010) and benthic
fauna sampling (Post et al., 2010), in the offshore of the George Vth Land, document evidence of bottom water
cascading currents and turbidity currents inside continental slope canyons.
The continental slope is incised by canyons heading to shelf edge sills and bounding sedimentary ridges of Miocene
age. Dense shelf water forms in coastal polynya and is exported off the shelf break to form the Adélie Land branch of
the Antarctic Bottom Water (ALBW, Rintoul et al., 2008). This bottom water is detected by CTD and mooring
measurements up to about 3200m of depth, in the Jussieu canyon and further to the west. The speed of the ALBW is
enough to transport fine sand and silt from shallow to deep water as documented by sea bed sediments. Similar bottom
currents activity is recorded also during Quaternary glacial and interglacials (Caburlotto et al., 2009, Macrì et al., 2005)
with source in the George V Land rocks and in the continental shelf (Damiani et al., 2006).
The meandering charater of the Jussieu canyon and the sediment wave field on its eastern ridge, would suggest that
they likely formed under the action of downslope, continous, bottom current, since the early Pliocene (Escutia et al.,
2010).
Caburlotto A., Lucchi R.G., De Santis L., Macrì P., Tolotti R. 2010. Sedimentary processes on the Wilkes Land
continental rise reflect changes in glacial dynamic and bottom water flow. International Journal of Earth Sciences,
99(4), 909-926.
Damiani D., Giorgetti G., Memmi Turbanti I. 2006. Clay mineral fluctuations and surface textural analysis of quartz
grains in Pliocene–Quaternary marine sediments from Wilkes Land continental rise (East-Antarctica):
Paleoenvironmental significance. Marine Geology, 226,81-295.
Escutia C., Brinkhuis H., Klaus A. & Expedition 318 Scientists 2011. Proc. Intergrated Ocean Drilling Program, 318.
Macrì P., Sagnotti L., Dinares-Turrel J., Caburlotto A. 2005. A composite record of Late Pleistocene relative
geomagnetic paleointensity from the Wilkes Land Basin (Antarctica). Physics of the Earth and Planetary interiors, 151,
223-242.
Post A.L., O’Brien P.E., Beaman R.J., Riddle M.J., De Santis L. 2010. Physical controls on deep water coral
communities on the George v Land slope, East Antarctica 2010. Antarctic Science, 22 (4), 371-378.
Rintoul S.R. 1998. On the origin and influence of Adelie Land bottom water. In: Ocean, Ice and Atmosphere:
Interactions at the Antarctic Continental Margin. American Geophysical Union, Washington DC, 151-171
Polar marine diatoms: key markers for Cenozoic environmental shifts. Sedimentary and paleo-environmental reports from Antarctic continental margin (Ross Sea, Wilkes Land and Prydz Bay)
No full textMarine diatoms are sensitive to water-mass distribution and their physical-chemical and biotic preferences affect their
biogeographical distribution. In sedimentary records, although altered by secondary processes such as dissolution, they
track the primary signal formed in surface water. This make them the major biostratigraphic and environmental markers
in the Southern Ocean as they record sea-surface temperatures, sea ice and other parameters usefull for
paleoceanographic and paleoclimatic reconstructions (Jordan et al. 2010; Leventer et al., 2010; Crosta, 2011; Escutia et
al., 2011). We present three case studies of diatom biostratigrapy and paleoceanographic reconstructions performed on
Antarctic sediments recovered from: 1) Pleistocene-Holocene sequences in the Ross Sea and Wilkes Lands, with
evidences of glacial/deglacial-interglacial phases (PNRA and IMAGES-CADO Projects in Atlantic and Australian
Sectors) (Caburlotto et al., 2010; Tolotti et al., 2013) and 2) Late Eocene-Early Miocene sequences in Prydz Bay, with
preliminary micropaleontological results and biostratigraphy related to the greenhouse/ice-house transition (ODP
Project in the Indian Sector) (Lagabrielle et al., 2009; Suto et al., 2012).
Jordan W.J. & Stikley C.E. 2010. Diatoms as indicators of paleoceanographic events. In: Smol J.P. & Stoermer E.F.
Eds., The Diatoms: Applications for the Environmental and Earth Sciences., II Edition., 424-452.
Escutia C., Brinkhuis H., Klaus A. & IODP Expedition 318 Scientists. 2011. IODP Expedition 318: From Greenhouse
to Icehouse at the Wilkes Land Antarctic Margin. Scientific Drilling, 12, 15-23.
Caburlotto A., Lucchi R.G., De Santis L., Macrì P. & Tolotti R. 2010. Sedimentary processes on the Wilkes Land
continental rise reflect changes in glacial dynamic and bottom water flow. International Journal of Earth Sciences,
99(4), 909 – 926.
Crosta X. 2011. Marine diatoms in polar and sub-polar environments and their application to Late Pleistocene
paleoclimate reconstruction. IOP Conf. Series: Earth and Environmental Science, 14, 1-18.
Leventer A., Crosta X. & Pike J. 2010. Holocene marine diatom records of environmental change. In: Smol J.P. and
Stoermer E. F. Eds., II Edition., 401-423.
Lagabrielle Y., Goddéris Y., Donnadieu Y., Malavieille J. & Suarez M. 2009. The tectonic history of Drake Passage
and its possible impacts on global climate. Earth and Planetary Science Letters, 279, 197–211.
Suto I., Kawamura K., Hagimoto S., Teraishi A. & Tanaka Y. 2012. Changes in upwelling mechanisms drove the
evolution of marine organisms. Palaeogeography, Palaeoclimatology, Palaeoecology, 339-341, 39–51.
Tolotti R., Salvi C., Salvi G. & Bonci M.C. 2013. Late Quaternary climate variability as recorded by
micropalaeontological diatom data and geochemical data in the western Ross Sea, Antarctica. Antarctic Science, 25(6),
804–820
Gibellini, Pietro; Caburlotto, Filippo (a cura di) (2009). D’Annunzio, Gabriele: Il Fuoco. Introduzione di Pietro Gibellini; note di Filippo Caburlotto. Milano: BUR
No full textNew insights into Quaternary glacial dynamic changes on the George V Land continental margin (East Antarctica)
No full textThe continental margin of the George V Land represents the seaward termination of one of the largest sub-glacial basins (the Wilkes Basin) of the East Antarctic Ice Sheet (EAIS) and hence is a potentially useful site for the investigation of the Cenozoic glacial history of Antarctica. Because the seafloor morphology relates strictly to recent glacial marine sedimentary processes, we have compiled all available echo-soundings data collected until the year 2001 and integrated the data set with satellite altimetry data. As a result, we have produced a new bathymetric map of the margin, covering an area of more than 80,000 km2 with a spatial resolution of about 1 km. The bathymetric data have been integrated with sub-bottom profiler data with the purpose of defining sedimentary processes and their variations during the Quaternary.The continental shelf of the Wilkes Land margin is characterised by alternating banks and glacial troughs connected to sub-marine canyons that cut into the continental slope. Our study focussed on the continental rise, where asymmetrical ridges alternate with large deep-sea channels. The ridges have a long gentle eastern side and short steep western side, with axis elongated approximately in north–south direction, perpendicular to the margin. The channels represent the main sediment drainage pattern feeding the ridge depositional system found along the continental rise. The sediment is supplied to the continental shelf edge by ice sheets, and sediment gravity flows are considered the main process for sediment supply to the rise.The modern sedimentary environment of the deep margin is affected by turbiditic down-slope sediment transfer with a minor contribution from along-slope contour currents. The WEGA channel is currently affected by transport and settling of sediment through High-Salinity Shelf Water (HSSW), originating on the continental shelf. We infer that thermohaline circulation has contributed to sediment transport and deposition since the mid-Pleistocene. <br/
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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