Dipartimento di Biologia, Ecologia e Scienze della Terra - Tesi di dottorato

Permanent URI for this collectionhttp://localhost:4000/handle/10955/34

Questa collezione raccoglie le Tesi di Dottorato afferenti al Dipartimento Dipartimento di Biologia, Ecologia e Scienze della Terra dell'Università della Calabria.

Browse

Search Results

Now showing 1 - 10 of 191
  • No Thumbnail Available
    Item
    Facies analysis and fluid inclusion studies of the Messinian evaporites, Calabria, Southern Italy
    (Università della Calabria, 2020-03-26) Cipriani, Mara; Critelli, Salvatore; Costanzo, Alessandra; Dominici, Rocco
    Messinian salinity crisis (MSC) is, from about 30 years, one of the most important and debated topic in the scientific community, both in environment and economic field. In this context, Calabrian evaporite deposits, poorly investigated in the past, offer an interesting opportunity to expand the knowledge because they confirm and increase the models created for other Mediterranean basins, and add important information on the main halite and gypsum facies. In this regard, saline evaporitic facies outcropping in the Crotone, Catanzaro and Ionic Basins were investigated using a multidisciplinary approach from classical petrography, to the study of fluid inclusions (FIs) to isotopic geochemistry. (A) The halite samples from the Crotone Basin have highlighted three primary facies; two known in the literature as banded and white while the third, never observed before, called in this work transparent. The transparent facies seems recrystallized but the analyses conducted show instead a primary origin. The three facies form in different environment and with a dissimilar deposition rate (fast or slow) due to pycnocline oscillation (daily or seasonal). Pycnocline oscillations can explain the different temperature of homogenization found within the FIs (from +20° to +33°C). The facies form in a hybrid brine (salinity av. ̴ 26.2 eq. wt% NaCl) enriched in Ca-Mg-Na-K-Cl elements, regardless of their deposition rates. During their fluid inclusions testifying plastic and ductile deformations that don’t remove primary features, demonstrating low recrystallization during burial process. Moreover, isotopic data attribute these facies at the second step of the MSC (5.6-5.5 Ma) during Halite deposition stage in the Mediterranean Basin. (B) The selenite samples from the Catanzaro Trough belong to banded and giant facies. The crystals record middle-frequency climatic oscillation between the depositional cycles and high-frequency climatic oscillation (seasonal) between cloudy and clear microfacies observed within the crystals. These microfacies testify a different brine condition associated with seasonal variation: cloudy intervals form during continental water inflow in the humid phase (Mg and Ca as dominant elements and low salinity values - av. ̴ 3 eq. wt% NaCl), while, clear intervals form in marine water during the arid phase (Na, K and Cl as dominant elements and high salinity values - av. ̴ 21.5 eq. wt% NaCl). Isotopic data attribute these facies at the third step of the MSC (5.5-5.3 Ma) placing, for the first time, the formation of the giant facies at the Upper Gypsum stage in the Mediterranean Basin. (C) The analyses conducted on the gypsum deposit from the Ionian Basin have shown that these crystals do not display primary features. This deposit is an olistostrome. The isotopic data confirm secondary origin attributing these facies at the second step of the MSC (5.5-5.3 Ma) during the Resedimented Lower Gypsum deposition stage in the Mediterranean Basin. The data obtained from the study of the Calabrian Messinian deposits indicate a surprising variety and diversity of evaporitic facies. In this work, it emerges that the formation of, crystals trap primary FIs and microalgae (blue, green and yellow). Primary FIs and organic matters, associated with secondary the different facies is strongly conditioned by climate (wet/arid) and intrinsic characteristics of the basin (depth, arrival of continental water flows etc.) which promote the development of one facies rather than of another.
  • No Thumbnail Available
    Item
    Arm growth and regeneration in octopus (Octopus vulgaris and Eledone moschata)
    (Università della Calabria, 2020-02-07) Baldascino, Elena; Cerra, Carmela; Fiorito, Graziano
  • No Thumbnail Available
    Item
    Edible oleogels: a rheological and microstructural analysis for structured emulsions design
    (Università della Calabria, 2022-06-01) Salvino, Samuele; Cerra, Maria Carmela; Gabriele, Domenico; Lupi, Francesca Romana
  • No Thumbnail Available
    Item
    Rheological analysis of complex interfaces and bulk behaviour of starches and pea protein
    (Università della Calabria, 2021-06-24) Paleologo, Mario Florio Oraldo; Cerra, Maria Carmela; Baldino, Noemi; De Cindio, Bruno
  • No Thumbnail Available
    Item
    Cardiac adaptation to hypoxia: goldfish as a natural animal model
    (Università della Calabria, 2020-11-29) Leo, Serena; Cerra, Maria Carmela; Imbrogno, Sandra; Filice, Mariacristina
  • No Thumbnail Available
    Item
    In search of genetic and epigenetic markers of human aging and longevity: a study in the Calabrian population
    (Università della Calabria, 2021-02-01) Iannone, Francesca; Cerra, Maria Carmela; Rose, Giuseppina
  • No Thumbnail Available
    Item
    Torsin a acting as a mechanosensor modulates nuclear transport in pathophysiological conditions
    (Università della Calabria, 2020-11-25) Galli, Giulia Raffaella; Cerra, Maria Carmela; Maggiolini, Marcello
    Gli esseri umani e l’ambiente circostante comunicano anche attraverso forze meccaniche. Gli input meccanici provenienti dal mondo che ci circonda svolgono un ruolo cruciale nei processi fisiologici e nel mantenimento dell’omeostasi dell’organismo umano. D'altra parte, difetti nelle proprietà meccaniche delle cellule o alterazioni delle forze meccaniche sono coinvolti nelle cause di diverse patologie tra cui il cancro. Le cellule del nostro corpo rispondono attivamente alle forze meccaniche, traducendo tali stimoli in segnali biochimici e nella regolazione dell'espressione genica. Il nucleo, costituito da due membrane separate che controllano il trasporto delle molecole, svolge un ruolo centrale nelle vie della meccano- trasduzione. Il trasporto nucleare delle molecole è meccanicamente sensibile ed è costituito da varie proteine coinvolte nel trasferimento di forze tra il citoscheletro e l'interno del nucleo. La ricerca condotta ha riguardato il ruolo dell'ATP-ase Torsin A come potenziale meccano-sensore in grado di rispondere ai cambiamenti della rigidità del substrato e modulare la traslocazione di proteine attraverso i pori nucleari. Sono stati pertanto studiati i cambiamenti nell'accumulo nucleare di MRTFA e YAP, poiché tali fattori di trascrizione sono fortemente sensibili ai segnali meccanici e risultano coinvolti nella progressione tumorale. Gli esperimenti sono stati eseguiti piastrando le cellule su gel di poliacrilammide con rigidità variabile e modulando i livelli di espressione di Torsin A attraverso tecniche di silenziamento genico ed over-espressione. In seguito ai cambiamenti di espressione di Torsin A è stata osservata un’alterazione nella traslocazione nucleare dei fattori di trascrizione summenzionati, supportando l'ipotesi 5 che Torsin A può agire nella meccano-sensibilità per il trasporto nucleare. L’utilizzo di costrutti mutanti di Torsin A ha ulteriormente consentito di dimostrare che Torsin A è coinvolta nel trasporto nucleare. Successivamente, sono stati anche valutati cambiamenti nella posizione di Torsin A in cellule piastrate su gel a diversa rigidità. Poiché il comportamento di Torsin A è fortemente dipendente dal cofattore noto come Lull1, che permette la traslocazione di Torsin A dal reticolo plasmatico all'involucro nucleare, la posizione di Torsin A in presenza e in assenza di tale cofattore è stata dunque valutata in cellule piastrate su gel a diversa rigidità. I risultati ottenuti hanno suggerito che la posizione di Torsin A è dipendente dalla presenza del cofattore Lull1. Inoltre, è stato osservato che l'accumulo di Torsin A nell'involucro nucleare diminuisce inibendo l'attività di Importin ß, indicando dunque che Importin ß è coinvolta nella localizzazione di Torsin A. È stato infine osservato che l’accumulo perinucleare di Torsina A è inversamente associato alla polimerizzazione dell'actina. Tali risultati indicano che Torsin A è un meccano-sensore in grado di rispondere ai cambiamenti della rigidità del substrato e di modulare la traslocazione nucleare di proteine coinvolte in importanti processi biologici.
  • No Thumbnail Available
    Item
    Geochemical modelling of natural contaminants in groundwaters and their removal by membrane processes
    (Università della Calabria, 2021-10-25) Fuoco, Ilaria; Critelli, Salvatore; Apollaro, Carmine; Marini, Luigi; Bartolo, Gabriele; Figoli, Alberto; De Rosa, Rosanna
    The presence of harmful elements dissolved in groundwaters represents one of the main environmental issues of present times. The aim of my PhD Thesis was to study the rock-to-water release and the fate of some inorganic pollutants dissolved in the groundwaters of the Calabria Region, and sometimes in other Italian areas, as well as to select suitable membrane technologies for their removal based on the acquired geochemical knowledge. Taking into account the peculiar characteristics of the groundwaters of the Calabria Region, three elements were considered: arsenic (As), fluorine (F) and chromium (Cr). The salient results of my PhD studies are presented in this Thesis, which is organized in four self-consistent Chapters structured as follows. Chapter 1. Geochemical modelling of As and F release into the crystalline aquifers of the Calabria Region. This section has been devoted to understanding the water-rock interaction processes occurring in the crystalline aquifers of the Calabria Region. Three different reaction path modeling exercises of granite dissolution were performed, reconstructing the water-rock interaction processes which occur: (i) in shallow and relatively shallow crystalline aquifers in which no As and F anomalies were observed; (ii) in As-rich areas, coupling the reaction path modeling of granite dissolution with the simulation of the adsorption of dissolved As onto precipitating crystalline and amorphous hydrous ferric oxide (HFO); (iii) in deep crystalline aquifers where high F concentrations were detected. A total of 160 water samples discharging from the crystalline aquifers of the Calabria region were used to fix the boundary conditions as well as to validate the outcomes of geochemical modeling. The results of the three geochemical modeling exercises of granite dissolution are in agreement with the analytical data and, therefore, it is reasonable to assume that they reproduce satisfactorily the water-rock interaction processes occurring during the travel of meteoric waters from shallow to deep crystalline aquifers, hosted both in granite rocks without mineralizations and in mineralized granites. Moreover, based on the results of the geochemical survey, some As- and F- rich groundwaters were selected and used as feeds for the treatment tests. Some relevant results have been already published by Fuoco et al. (2021a). Chapter 2. Geochemical modelling of Cr(VI) release into the ophiolite aquifers of Italy. This section has been focused on the water-rock interaction processes occurring in the main ophiolite aquifers of Italy. The obtained results were already published by Apollaro et al. (2019a). Reaction path modelling of serpentinite dissolution was performed varying the Fe2O3/(FeO +Fe2O3) weight ratio of serpentine and reproducing the analytical concentrations of relevant solutes, including Cr(VI), in the Mg-HCO3 groundwaters hosted in the ophiolite aquifers of Italy. The occurrence of geogenic Cr(VI) in these groundwaters appears to be potentially controlled by the oxidation of trivalent Cr to the hexavalent redox state, driven by the reduction of trivalent Fe to the divalent redox state. In fact, trivalent Fe is the only oxidant present in suitable amounts in serpentinite rocks, and even serpentine contains high contents of trivalent Fe as proven by recent studies. In contrast, the generally accepted hypothesis that geogenic Cr(VI) in waters interacting with serpentinites is driven by the 2 reduction of trivalent and tetravalent Mn is questionable. To validate the outcomes of the geochemical modeling of serpentinite dissolution and rock-to-water release of Cr(VI), the redox state of Fe in serpentine minerals of different Italian areas was measured (see next section). Moreover, the water sample characterized by the highest concentration of Cr(VI) was selected for the treatment tests. Chapter 3. Determination of the iron redox state in serpentine minerals by using TEMEELS analysis and its environmental implications. This section has been addressed to determine the Fe3+/FeT ratio of the serpentine minerals hosted in five serpentinite samples coming from the main ophiolite areas of Italy, in order to validate the results of the geochemical modeling of serpentinite dissolution and rock-to-water release of hexavalent chromium (see previous section). The electron energy-loss spectroscopy (EELS) combined with transmission electron microscopy (TEM) was selected as most suitable analytical technique because it provides the highest spatial and energy resolution allowing to obtain a good qualitative and quantitative information on iron redox speciation compared to other analytical techniques. Ten site-specific TEM foils were prepared and analyzed in the laboratories of the GFZ German Research Centre for Geosciences, in Potsdam. It has not been the simple application of a well-established analytical technique, but rather a challenging study, because it has been necessary to develop a new spectra processing method and prove its validity. The performed analyses provided in-depth knowledge on nanoscale structures of the studied samples and showed that Fe3+ represents from 75 to 85 % (median values) of total iron. The obtained results provide further support to the hypothesis concerning the oxidation Cr(III) to Cr(VI) driven by the concurrent reduction of Fe(III) to Fe(II), as suggested by geochemical modeling (see previous section). Chapter 4. Application of membrane processes to remove As, F and Cr(VI) from contaminated groundwaters. This section has been devoted to the removal of As, F and Cr from polluted groundwaters by means of membrane processes. Relevant results have been already published by Figoli et al. (2020), Fuoco et al. (2020) and Fuoco et al. (2021b). The geochemical approach was used as strong-scientific tool for pre-selection of suitable remediation systems and the contaminated groundwaters were chosen from the previous data collections. Several type of commercial nanofiltration/reverse osmosis membranes, not already tested in the pertinent literature, were selected depending on the type of application. Their efficiency was evaluated in terms of arsenic, fluoride and chromium rejection, water production and feed composition. The other main ions that contribute to water chemistry were also taken into account to evaluate the possible intended use of the considered waters after the treatments. Satisfactory results were obtained for each specific case of contamination. Moreover, an innovative membrane with absorbent capacities against As(III) and As (V) species was developed and the preliminary results are quite promising. Summing up, the findings obtained in this work are useful for the understanding of the rock-to-water release of the chemical elements of interest and their fate in natural waters. Moreover, the treatment of natural As, F, and Cr-contaminated groundwaters improved the knowledge and the data availability for future scientific and application developments in similar geological settings worldwide.
  • No Thumbnail Available
    Item
    The effect of cholesterol on the function of eukaryotic membrane transporters for amino acids
    (Università della Calabria, 2020-11-25) Cosco, Jessica; Cerra, Maria Carmela; Indiveri, Cesare
    Amino acid transport in mammalian cells is mediated by different amino acid transporters. Amino acid flow, which is important under physiological conditions, becomes particularly relevant under pathological conditions such as in cancer cells where high demand for these nutrients is required to satisfy the uncontrolled growth and proliferation. Therefore, to guarantee a sufficient supply of nutrients a lot of amino acid transporters are highly expressed in cancer cells. In this context, the amino acid transporters hLAT1 and hASCT2 are widely studied for their role as potential targets for drug development. hASCT2 belongs to SLC1 family and assembles at the plasma membrane as a trimeric complex. Studies conducted using the recombinant protein showed that this transporter is strongly stimulated by cholesterol. The stimulation is due to an improvement of protein insertion in the phospholipid bilayer and direct interaction with the protein. In fact, cholesterol increased the Vmax of the transport, without affecting the external Km, indicating that it increases the rate of conformational changes. Thanks to docking analysis, 6 putative cholesterol binding sites were predicted, some of these matched with the electron densities identified on the cryo-EM structure of ASCT2. Two poses are on the TM6, where a CRAC and a CARC motif has been identified. Experimental demonstrated the direct binding of cholesterol to the protein. In particular, Koshland’s reagent and SH-reagents have been used for the target of tryptophan and cysteine residues close to the cholesterol poses. hLAT1 belongs to SLC7 family and it forms a heterodimer complex (HAT) with the glycoprotein 4F2hc (also known as CD98 in mice), a member of SLC3 family. hLAT1 is the sole component involved in the transport of essential amino acids, as previously demonstrated (Napolitano, Scalise et al. 2015). In this work, the influence of cholesterol has been evaluated on the recombinant protein hLAT1. Moreover, putative regulators involved in energy metabolism have been tested on the transport. The transport activity increased up 75 μg cholesterol/ mg phospholipids. Moreover, the internal substrate affinity increased in the presence of cholesterol suggesting a stabilization of the inward conformation of hLAT1. The transporter is also stimulated by ATP at physiological concentration. This effect occurs only in the presence of cholesterol and was seen also on the native protein. This finding suggested that cholesterol and ATP binding sites are close to each other. The computational analysis confirmed this hypothesis. In fact, a hydrophobic region between the TMs 1, 5 and 7 was found to be close to a hydrophilic one. Docking results for ATP suggested an electrostatic interaction of the ϒ-phosphate of ATP with Lys 204, which was confirmed by site-directed mutagenesis. This residue is conserved in the other SLC7 proteins and for a serendipity event, it has been seen that Lys204 is also important in the substrate binding and pH-sensitive. In this work, the attention was focused also on another amino acid transporter CAT2, from Solanum lycopersicum. The specific interest in tomato resides in the well-recognized role for this species in biotechnology. In fact, tomato has been used as the primary model for the study of climacteric fruit ripening. SlCAT2 belongs to APC superfamily, as LAT1, and it is involved in the transport of cationic amino acids like arginine, lysine and the non-proteogenic amino acid ornithine. The experimental data on CAT2 highlighted an asymmetric regulation by cations and osmotic pressure, in line with the localization of the transporter in vacuoles. Like the other human transporters, CAT2 is also stimulated by cholesterol. On the basis of the 3D structure of the amino acid transporter GkApcT, the homology model of SlCAT2 was built and putative substrate binding residues and cholesterol binding domains were proposed. Altogether, the described results open new perspectives for studying the response of membrane transporters to metabolic and membrane changes. Moreover the identification of hydrophobic or hydrophilic sites interacting with cholesterol or physiological effectors, respectively, could be important for applications in human pathology.
  • No Thumbnail Available
    Item
    Effetto del bisfenolo A sulla vascolatura uterina materna e sull'unità feto-placentare
    (Università della Calabria, 2021-12-01) Barberio, Laura; Cerra, Maria Carmela; Mandalà, Maurizio