Browsing by Author "Cerra, Maria Carmela"

Now showing 1 - 20 of 44

Angiotensin II and mechanisms of oxidative damage in HUVECs
(2011-12-14) Carino, Annarita; Cerra, Maria Carmela; Martino, Guglielmo
The endothelium is essential for the maintenance of vascular homeostasis. Central to this role is the production of endothelium – derived nitric oxide (EDNO), synthesized by endothelial isoform of nitric oxide synthase (eNOS). Endothelial dysfunction, manifested as impaired EDNO bioactivity, is an important early event in the development of various vascular disease, including hypertension, diabetes, genesis of tumors and atherosclerosis. Endothelial dysfunction is an early feature of atherosclerosis vascular disease, characterized by a decrease in nitric oxide (NO) bioavailability and a concomitant increase in vascular superoxide (O2 . -) formation. Loss of NO bioavailability precedes the development of overt atherosclerosis and is an independent predictor of adverse cardiovascular events. Indeed, decreased NO and enhanced production of reactive oxygen species (ROS) have been recognized as major determinants of age-associated endothelial dysfunction. The degree of impairment of EDNO bioactivity is a determinant of future vascular complications. Accordingly, growing interest exists in the pathologic mechanism involved. However it is clear that immunologic mechanisms operating in the context of common cardiovascular risk factors lead to impaired endothelial function, mainly as a consequence of decreased NO bioavailability and excessive oxidative stress. The work submitted in this thesis describes on one side studies aimed to investigate cellular mechanisms underlying endothelial dysfunction and vascular damages driven by oxidative stress in the context of aging, hypertension and atherosclerosis using in vitro models. In addition, we desired to evaluate the efficacy of reducing agents such as flavonoid to monitor whether they actually have an action to recover from the cellular oxidative damage by these natural compounds and how real is their action at the level of microcirculation in vitro models. On the other side, we present studies focused on the pathophysiology of microcirculation as far as functional aspects are concerned in the context to better understand the functioning of the Renin- Angiotensin-System in particular if the Angiotensin IV is involved in mechanisms of oxidative stress and in Calcium intracellular levels.
Biodiversità dei carabidi e conservazione degli ambienti forestali
(2014-03-25) Pulieri, Valeria; Cerra, Maria Carmela; Brandmayr, Pietro
4 Abstract Resilience, stability and resistence of forest ecosystems are the main properties providing the conservation of those habitats and allowing the maintenance of processes essential for the “ecosystem services” supply. In front of climate change and other disturbances coming from human activities, it is of fundamental importance to watch and check stability status of ecosystems. Ground beetles, good bioindicators, by their community composition, functional groups and morphometric sensitivity, provide indicators on habitat conservation evaluation and contribute to identify little changes among areas looking similar. The analisys of biodiversity could be improved by considering the above factors, enhancing the functional role of single species of the community.
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
Cardiac plasticity in fish: the influence of humoral and environmental factors
(2018-06-22) Filice, Mariacristina; Cerra, Maria Carmela; Imbrogno, Sandra
Il rimodellamento cardiaco è un fenomeno complesso che permette un’adeguata attività d’organo in risposta a cambiamenti fisiologici e patologici e coinvolge modificazioni a livello tissutale, cellulare e molecolare, secondo meccanismi ancora poco noti. Il cuore dei vertebrati mostra una notevole capacità di adattarsi funzionalmente alle richieste emodinamiche dell’organismo. Questa plasticità è esemplificata dalla modulazione “beat-to-beat” della contrattilità in risposta a cambiamenti del carico pressorio e volumetrico (risposta di Starling) e dal riarrangiamento morfo-funzionale adattativo. I maggiori determinanti della risposta plastica del cuore sono gli stimoli fisici come lo stress meccanico e lo stiramento dei miociti, o chimici, come ad esempio quelli esercitati da cardiomodulatori, inclusi i Peptidi Natriuretici (NPs), l’endotelina-1 (ET-1), l’Ossido Nitrico (NO) e l’Angiotensina II (AngII). Queste molecole attivano specifici circuiti endocrini/paracrini/autocrini responsabili del controllo omeostatico della funzione e della crescita cardiaca. Nei mammiferi, il cuore adulto è considerato un organo terminalmente differenziato nel quale la crescita e il rimodellamento avvengono per ipertrofia. Questo paradigma è stato recentemente confutato da evidenze che mostrano come, durante la normale crescita cardiaca, i miocardiociti adulti proliferano e muoiono. L’identificazione di stimoli e meccanismi che, attivando programmi genetici e/o metabolici silenti, possano permettere ai cardiomiociti di mammifero adulto di proliferare, è al momento tra gli scopi più importanti della ricerca cardiovascolare moderna. A tal riguardo un possibile approccio è quello di identificare esempi di plasticità cardiaca fra i vertebrati. Negli ultimi anni il cuore dei pesci ha rappresentato un importante strumento di ricerca per analizzare aspetti molecolari, cellulari e tissutali della plasticità cardiaca. Nei pesci, il cuore adulto conserva la capacità di crescita iperplastica in risposta a cambiamenti delle condizioni ambientali, all’esercizio fisico e alla maturità sessuale. Esempio estremo di questa plasticità è rappresentato dalla completa rigenerazione del cuore di zebrafish in seguito a rimozione chirurgica di una porzione del ventricolo. In una prospettiva traslazionale, i risultati di studi effettuati nei pesci potrebbero rappresentare uno strumento importante per decifrare i determinanti e i meccanismi coinvolti nel rimodellamento morfo-funzionale del cuore dei mammiferi. Partendo da queste premesse, questo progetto di tesi ha voluto valutare se e in che misura, fattori umorali e ambientali influenzano la plasticità cardiaca dei pesci. In particolare, in questa tesi di dottorato sono riportati e discussi i risultati ottenuti da studi relativi al controllo umorale del rimodellamento morfo-funzionale cardiaco mediato dall’esposizione cronica all’AngII nel cuore dell’anguilla europea Anguilla anguilla e dello zebrafish Danio rerio, e i meccanismi fisiologici e molecolari attivati nel cuore della carpa, Carassius carassius, in risposta all’ipossia. L’AngII, il prodotto bioattivo del Sistema Renina Angiotensina (RAS) è un potente ormone le cui azioni biologiche sono state ampiamente studiate nei mammiferi. A livello cardiaco, legandosi a recettori di tipo AT1 e AT2, l’AngII influenza positivamente la contrattilità miocardica e regola la crescita miocitaria. Un RAS omologo a quello dei mammiferi è presente anche nei pesci. In particolare, nei teleostei, l’AngII può indurre modificazioni cardiache a breve (modulazione della contrattilità) e lungo termine (rimodellamento morfo-funzionale). Nel 2013, Imbrogno e collaboratori hanno dimostrato che il cuore di anguille esposte per 4 settimane ad iniezioni intraperitoneali di AngII mostrava una migliore capacità di rispondere ad incrementi di post-carico. Quest’effetto era mediato dall’attivazione dei recettori AT2 e accompagnato da una differente espressione e localizzazione di proteine coinvolte nella regolazione della crescita e dell’apoptosi. Partendo da queste premesse, questo studio ha voluto meglio investigare le modificazioni strutturali e molecolari attivate nel cuore di anguille esposte per 8 settimane ad iniezioni intraperitoneali di AngII. Analisi morfologiche hanno evidenziato che i cuori di animali trattati mostravano un incremento della muscolarità ventricolare associato ad un aumento dello spessore del compatto e ad una riduzione degli spazi lacunari nello spugnoso. Queste modificazioni erano accompagnate da un’incrementata vascolarizzazione del compatto. Analisi di western blotting e immunofluorescenza hanno evidenziato un’aumentata espressione del recettore AT2 nei cuori di animali trattati, associata ad una diversa localizzazione: nei controlli AT2 localizza principalmente a livello miocitario mentre in seguito a trattamento, un segnale fluorescente si osserva a livello dell’endotelio endocardico. In relazione al ruolo cruciale svolto dallo NO nei meccanismi di regolazione del rimodellamento cardiaco nei pesci, lo studio ha voluto anche analizzare il cross-talk tra AngII e il sistema NO Sintasi (NOS)/NO. In condizioni basali, lo NO prodotto dalla NOS viene immediatamente metabolizzato a nitriti o nitrati. Per questa ragione, il dosaggio dei nitriti può essere utilizzato per misurare i livelli di NO prodotti dalla NOS e di conseguenza la funzionalità stessa dell’enzima. Il dosaggio dei nitriti, effettuato su omogenati di cuori di animali trattati con AngII ha evidenziato una riduzione significativa della concentrazione di nitriti rispetto ai controlli, indice di una ridotta attività della NOS. Analisi di western blotting non hanno evidenziato variazioni significative nei livelli di espressione della forma fosforilata (e quindi attiva) della NOS. Tuttavia, il trattamento ha influenzato la localizzazione dell’enzima fosforilato. Infatti, mentre nei controlli peNOS localizza sia nei miociti che a livello dell’endotelio endocardico (EE), nei trattati si osserva una maggiore localizzazione a livello miocitario e solo un debole segnale a livello endocardico. Questo dato è accompagnato da una maggiore espressione, a livello dell’EE, di NOSTRIN, un modulatore negativo della NOS, responsabile della traslocazione dell’enzima dalla membrana plasmatica all’interno di vescicole citoplasmatiche. Analisi di western blotting hanno anche evidenziato una riduzione nei livelli di espressione della chinasi Akt e dello chaperone HSP90, due tra i principali modulatori positivi della NOS. Nel complesso questi risultati dimostrano che il cuore di anguilla cronicamente esposto all’azione dell’AngII va incontro ad un riarrangiamento strutturale e ad una modulazione dei livelli di NO e delle proteine che regolano l’attività della NOS. Gli effetti cronici dell’AngII sono stati investigati anche nello zebrafish. Sebbene questo studio è ancora in corso, i primi risultati sperimentali dimostrano che anche il cuore di zebrafish va incontro ad un rimodellamento strutturale se esposto per 8 settimane all’azione dell’AngII. In particolare, i cuori trattati con AngII mostrano un incremento del compatto e una riduzione degli spazi lacunari, indicativi di un aumento della muscolarità ventricolare. Questo è associato ad un aumento del collagene e ad un significativo aumento del peso del cuore e dell’indice cardiosomatico (rapporto in percentuale tra il peso del cuore e il peso dell’animale). Analisi di western blotting hanno evidenziato inoltre un’aumentata espressione di entrambi i recettori AT1 e AT2 in omogenati cardiaci di animali trattati con AngII. La seconda parte della tesi ha analizzato i meccanismi fisiologici e molecolari attivati nella carpa in risposta all’ipossia. A differenza dei mammiferi, alcune specie di pesci, come ad esempio i ciprinidi, mostrano una notevole capacità di sopravvivere e restare attivi anche per lungo tempo se esposti a condizioni di ipossia o anossia. Questa capacità è legata alla loro abilità di mantenere o aumentare la performance cardiaca in risposta ad una riduzione di ossigeno ambientale, favorendo così gli scambi tra i tessuti. Inoltre, questi pesci sono in grado di convertire il lattato (prodotto ultimo della glicolisi) in etanolo, che è poi eliminato attraverso le branchie. Una caratteristica dei pesci è la loro capacità di captare, attraverso le branchie, nitriti e nitrati dall’acqua in cui si trovano; in condizioni di ipossia, quando l’attività della NOS è compromessa, i nitriti possono rappresentare un’importante fonte di NO che, a sua volta, interviene nei processi di citoprotezione. Sulla base di queste osservazioni, in collaborazione con il Prof. Jensen (Università di Odense) e la Prof.ssa Fago (Università di Aarhus), è stato avviato uno studio volto a valutare il ruolo dei nitrati e della mioglobina come fonti alternative di nitriti, e quindi di NO, nella carpa esposta per un giorno ad ipossia profonda (1
Chronic kidney disease as an age related disease: new study perspectives fron animal models to hospitalized patents
(2019-04-11) La Russa, Daniele; Cerra, Maria Carmela; Pellegrino, Daniela; Montesanto, Alberto
Chronic kidney disease (CKD) is a major public health problem worldwide and its main consequences include the loss of renal function leading to end-stage renal disease (ESRD), an increased risk of cardiovascular disease (CVD), a significant increase in morbidity and mortality, and a decrease in health related quality of life. The risk of CKD increases with age, though there seems to be a complex relationship between ageing and this disease: elderly patients are overrepresented in the dialysis population and geriatric complications are highly detectable in younger patients with ESRD. This has led to the hypothesis of a premature biological ageing process of different organ systems associated with CKD. The present research work was based on translational approach to study the role of many CKD risk factors such as hypertension, oxidative stress/inflammation, obesity, and hyperuricemia with the aim of identifying new molecular mechanisms of kidney damage to prevent it by successful behaviour modifications. For this purpose, both human and animal models were used. Human pathological models: in both ESRD and obese patients, the role of oxidative stress, inflammation and hyperuricemia in progression and complications of CKD was investigated. Human physiological models: in a consistent healthy population, the oxidative status and its correlation with traditional cardiovascular risk factors were examined. In addition, the health history data of centenarian subjects was utilized to study the clinical and prognostic value of traditional cardiovascular risk factors in relation to mortality. Animal models: the mechanisms renal damage, induced by hypertension (Spontaneously Hypertensive Rat) and obesity (Cafeteria diet rats), were verified. In this context, the antioxidant and cytoprotective effects of a nutraceutical (Bergamot extract) on obesity was also tested. This multilevel approach has allowed us to individually and synergistically analyze some aspects of the complex pathogenic mechanism of CKD, in order to clarify the role of the new amplifying risk factors for CKD and to prepare an effective personalized prevention plan by acting on both modifiable and non-modifiable risk factors.
Development of new bio-materials and technologies for the green regeneration of RAP
(Università della Calabria, 2021) Loise, Valeria; Cerra, Maria Carmela; Oliverio Rossi, Cesare
Il presente lavoro di ricerca ha avuto come scopo lo sviluppo di nuovi rigeneranti green per il fresato d’asfalto, noto anche come reclaimed asphalt pavement (RAP). Questa ricerca nasce dalla necessità di aumentare l’uso del RAP nelle pavimentazioni stradali. L’uso del RAP ha sia un impatto economico positivo, infatti non è necessario usare inerti e bitume fresco, ma soprattutto ha un alto un impatto in termini di ecosostenibilità, il RAP da rifiuto da smaltire diventa di fatto materia prima, implementando l’economia circolare e l’end waste. Infatti il riuso del fresato d’asfalto consentirebbe di non trattare più questo materiale come uno scarto, con tutti le relative problematiche ambientali derivabili, ma bensì come una risorsa. Inoltre sono state sviluppate ed implementate tecniche di indagine chimico-fisiche e nuove metodologie per determinare i meccanismi di azione di un rigenerante sulla struttura del bitume e distinguere in modo univoco un rigenerante da un semplice flussante. Tale tesi è stata la base scientifica che ha permesso di definire una norma europea e nazionale da seguire per le aziende che commercializzano rigeneranti bituminosi. Spesso infatti il fresato d’asfalto viene trattato con agenti che non modificano la struttura colloidale del bitume riportandola alla loro struttura originaria, ma che semplicemente hanno una mera attività flussante (abbassare la viscosità del sistema). Le “classiche” metodologie di indagine generalmente basate su parametri fisici-meccanici ed ingegneristici, non sono sufficienti per discriminare l’azione di un rigenerante da quella di un flussante. Tale approccio finora comunemente usato ha avuto un forte impatto sulla durata e qualità delle pavimentazioni stradali, effetto devastante dal punto di vista economico, sociale e soprattutto ambientale. The present research aimed to develop a procedure and methodologies that could uniquely distinguish between a fluxing agent and a rejuvenating agent. Recently, it has been realized that the reclaimed asphalt pavement (RAP) was a resource of considerable importance. In fact, it contains an appreciable amount of binder, which under certain conditions can be recycled for the construction of new pavements, thus reducing not only costs but also the use of raw materials. Therefore, this allows to consider the RAP more as a resource than a waste. Most of the time, the bitumen obtained from the RAP is treated with agents that have a mere flux function (lowering the viscosity of the system). These agents do not modify the colloidal structure of the bitumen. Therefore, they are not able to restore the structure of the aged bitumen to that of the neat bitumen. Furthermore, the investigation methodologies generally used to counter the regenerating effect of an additive are based on physical-mechanical and engineering parameters. These parameters are almost always insufficient to discriminate the action of a regenerant from that of a flux. For this reason, chemical-physical investigation techniques have been developed and implemented to determine the action mechanisms of a rejuvenator on the inner structure of the bitumen. In this way, it was possible to uniquely discriminate between a real rejuvenator and a fluxing agent. Finally, this thesis was the scientific basis that allowed the definition of a new European and National standard to be followed for companies that market bituminous regenerants.
Distribuzione e analisi funzionale dei neuromodulatori in Octopus vulgaris
(2017-03-13) Ponte, Giovanna; Cerra, Maria Carmela; Fiorito, Graziano
ments the pattern of distribution of biogenic amines in the brain of the cephalopod mollusc Octopus vulgaris. The data show that dopamine, noradrenaline and octopamine are not ubiquitary in the brain, as considered before, and that a division of labour between visual and tactile processing system exists. These data largely revise previous available knowledge and for the firt time depict the distribution of octopamine in the brain of the octopus. This despite this molecule has been for the first time discovered in the salivary gland of this animal more than 100 years ago.
DNA methylation patterns in aging and aging phenotypes
(2019-04-11) Guarasci, Francesco; Bellizzi, Dina; Cerra, Maria Carmela
During my PhD program, my work has been addressed to the study of the role of epigenetic modifications in aging and in age-related phenotypes. Epigenetics is the study of changes in gene expression that do not involve changes to the underlying DNA sequence. These changes affect cellular phenotypic expression by regulating relative gene expression levels. They are a common and natural process in living cells and are tightly controlled by pre-programmed mechanisms. Epigenetics modifications can be influenced by multiple factors including environmental conditions, lifestyle, nutrition, use of drugs, disease state and age. Patterns of DNA methylation, the best known and characterized epigenetic modification, change during aging; indeed, with increasing aging, genome-wide methylation levels decrease, meanwhile genomic regions, including CpG islands, become more methylated. Analyses of the above patterns provided new perspectives for establishing powerful biomarkers of human aging which have the potential to generate accurate prediction not only of the chronological but also of the biological age. The first section of the PhD thesis consists in a comprehensive overview of the general features of DNA methylation and its implication in age and age-related diseases. The topic is addressed referring to the methylation patterns established not only at nuclear but also at mitochondrial genome level. In addition, the influence of a number of environmental factors on the above patterns is also discussed. In the second section, an original research work, carried out in order to identify novel biomarkers of aging, is reported. In this work, methylation status of nuclear genes involved in mitochondrial fusion, fission, biogenesis and mitophagy, fundamental components of the mitochondrial quality control process, was investigated in subjects of different ages of the Calabrian population. The methylation levels of RAB32 and RHOT2 genes were significantly associated with age and, in particular, those of RAB32 even with the risk of developing disability. The study, therefore, led to the identification of two new biomarkers for both chronological and biological aging. In the Appendix, research works already published are reported. The first one concerns the correlation between DNA methylation and nutrition during lifetime. Global DNA methylation profiles were examined in different tissues of rats of different ages, fed with a standard and hypocaloric diet, and their association with aging and nutrition was evaluated. The results obtained have shown that tissue-specific variations in methylation levels occur during aging and that nutrition influences the state of global DNA methylation during the course of life. The hypocaloric diet seems to influence more strongly the epigenetic status of the offspring when administered during the maternal pre-gestational period compared to the gestation and lactation period. Therefore, changes in the global DNA methylation status represent an epigenetic mechanism by which age and nutrition intersect each oth and, in turn, influence the plasticity of aging. The second one is a review on the current advances in mitochondrial epigenetics studies and the increasing indication of mtDNA methylation status as an attractive biomarker for peculiar physiological and pathological phenotypes. It comes from the increasing evidence on the fact that, similarly to nuclear DNA, also mtDNA is subject to methylation and hydroxymethylation and these modifications are influenced by multiple environmental factors.
Eco-friendly additives for sustainable road pavements
(2019-04-18) Caputo, Paolino; Cerra, Maria Carmela; Rossi, Cesare Oliverio
L'obiettivo del presente studio è quello di sviluppare e valutare l'efficacia di nuovi additivi non tossici ed eco-compatibili per il settore delle pavimentazioni stradali. Attualmente, in tale settore, c'è la tendenza ad adottare pratiche eco-sostenibili rivolte alla salvaguardia della salute dei lavoratori e dell’ambiente. Nella presente ricerca i nuovi additivi sono stati caratterizzati e sviluppati al fine di ridurre le emissioni dei fumi potenzialmente tossici rilasciati dal bitume nell'atmosfera durante la produzione e la lavorazione dell’asfalto. Inoltre sono stati formulati e studiati nuovi bioadditivi capaci di migliorare l’adesione tra bitume e aggregati, modificare le caratteristiche reologiche del legante e migliorarne la resistenza all’invecchiamento (funzione antiossidante).
Ecologia e biologia riproduttiva in una popolazione alloctona di Trachemys scripta elegans in Calabria
(2012-12-14) Crescente, Antonio; Cerra, Maria Carmela; Tripepi, Sandro
This research was carried out from 2009 to 2011 in the Lake of Angitola on the reproductive biology of the slider turtle Trachemys scripta elegans, an alien species that in this site has been naturalized since the 1980’s. According to the International Union for Conservation of Nature (IUCN), invasive species are one of the most important causes of biodiversity decline on a global scale. As a consequence, the impact of introduced species on local ecosystems is important to evaluate. Pet voluntary introductions are done by private people and usually concern only the release of a few individuals. However, the number of releases is as numerous as the number of pet owners that don't want to keep their pet anymore and consequently decide to "release" it. Although only a small percentage of these alien species will become invasive, the environmental impact would be insidious and often irreversible. In fact on a global scale alien species may be as damaging to native species and ecosystems as the loss and degradation of habitats. We can describe 3 steps in the biological invasions processes, comprising the initial dispersal, when an organism moves long distances to areas outside its native range, for example through human assisted dispersal; establishment of self-sustaining populations within the non-native range; and invasion of the new range. However, when species are invasive, they have strongly positive demographic trends and are often numerous, therefore their management can be extremely difficult and expensive. Our experimental model was Trachemys scripta elegans, the most popular freshwater turtle in the pet trade in the world. It is a medium to large-sized turtle as females reach a carapace length of up to 24 cm and males up to 20 cm. This reptile lives in a wide variety of freshwater habitats and it is a habitat generalist. It prefers larg pools and ponds with soft bottoms, and with many aquatic plants and suitable basking sites for thermoregulation. Trachemys scripta elegans is an opportunistic omnivore subsisting on a wide variety of plant and animal foods. The food preferences change with age. Juveniles are highly carnivorous. Instead the adults, mainly eat vegetable food. In the late 1970s a several turtle farms were established in southern USA, where the hatchlings are packed, in hundreds in small boxes, and are shipped abroad. At least 80% of them die during the first year in captivity. If released terrapins survive in nature, they pose a threat to local wildlife. Only in 1996 the total exports of Trachemys scripta elegans from USA were 8 million individuals, of which 3 million individuals were imported by Europe. With effect from 1997 the EU implemented a ban on the import of this species, in fact already in 1975 the U.S. Food and Drug Administration banned the sale of turtles under 10 cm carapace length in the United States and Canada because they transmitted human salmonellosis. Trachemys scripta elegans distribution includes eastern USA, in particular the Mississipi valley from Illinois to the Gulf of Mexico. It now has a far greater distribution area that include a lot of countries in America, Europe and Asia, where it has naturalized in some cases. Trachemys scripta elegans released in seminatural conditions were first recorded in Campobasso in the early 1970s, but sightings only becoming more common in the mid-80s. It is presently known in all of Italy except for Valle d’Aosta, Sardinia and Campania. Reproduction is common in captivity, but little is known about its reproduction in nature. Some authors suggest that naturalization wouldn’t be a serious problem, but it is known that this species is certainly able to reproduce in Friuli Venezia Giulia, Latium, Emilia Romagna and in Calabria. This research was aimed to investigate reproductive biology of Trachemys scripta elegans in order: • to evaluate if reproduction is an effective phenomenon that could interest the study area; • to estimate the reproductive success in natural condition; • to determine preferences of Trachemys scripta elegans in the nest site selection; • to define the step of the invasion process of slider turtle in the Lake of Angitola, in order to suggest conservation measures. The research was conducted at Lake of Angitola, a 196 ha artificial lake located about 5 km from Pizzo Calabro. The lake became a WWF oasis in 1975, and ten years later was declared an International Ramsar area due to the large presence of migratory birds. Today the lake is included in the Regional Park of Serre and in 2005 the area was proposed as a Site of Community Importance (SIC) by ministerial decree. The climate is typically Mediterranean; the vegetation is very varied: the shrub layer is formed by aromatic herbs; the arboreal layer includes a forests of genus Quercus . The animal communities are very interesting, especially the bird population; in fact we can see more than 150 different species per year. The study was conducted from three years, and included 3 monitors per month, in particular from April to October, when the turtles were more active. The lake’s shores were divided into eight transects using environmental criteria. Data collection were sampling focused on visual census observations, on the nesting sites research and on trapping. Also to analyze the nest site selection we divided the whole lake perimeter by differing vegetative covers and differing soil types to study the use of these selected environments by nesting females. Vegetative cover was classified by five categories by a buffer of 50 m, and including shrub land, grass, fruit growing and reforestation; mixed category was used in cases where no one coverage was present in more than 75% of the subdivisions. Soil type was classified by using the methodology of Casanova (1991), yielding three main categories of dirt, sand and clay substrates and the possible combination of them. Collected variables used in this research were tested with InStat 3.0 software; in particular we used Chi-square goodness of fit, Kruskal-Wallis and Spearman Rank Correlation tests. The results of the visual census showed that Cavalcavia was the preferred basking area for Trachemys thermoregulation. In fact, in this area was observed the highest percentage of turtle presence that performed basking on the emerged deadwood. The heterogeneity χ² test, that was used to compare number of observation and the areas, was statistically significant (N=2015; χ²=893,03; d.f.=5; P‹0,0001). Monthly monitoring activities of basking showed an increasing of turtle presence from April to July, and it is possible to observe a subsequent decreasing of basking activities from August to October. During the research we found 229 nests. The greatest distance of a nest from the shoreline was 100 m, but the greatest number of nests was found between 0 and 20 m from the shoreline. Kruskal-Wallis non-parametric test association between number of eggs and months of the year was statistically significant (KW=14,318; P=0,0137). “Movrella” and “Ceramida” were the main nesting areas; in these transects there are a lot of emerged spaces that female turtles can use for nesting activities. The correlation between the number of eggs and the depth of the nest was statistically extremely significant (N=229; r=0,2105; P<0,0001). More than 85% of nests were found in mixed soil type habitats, particurarly in dirt-sand and dirt-clay soil types. Chi squared test between number of nests and soil type categories was statistically significant (N=229; χ²=116,22; d.f.=3; P<0,0001). More than 65% of nests were found in environments with mixed vegetative cover (Grass+Shrubland). Chi squared test associations between number of nests and the 4 vegetative cover types were statistically significant (N=229; χ²=116,22; d.f.=3; P‹0,0001). We collected by trapping, and marked 26 specimens and in particular 6 juveniles; the more effective trapping method was represented by “basking trap”, that we used on the water surface. In Europe reproduction under natural conditions has been reported only for Spain and France. As we said before, little is known about Trachemys scripta elegans reproduction out of captivity in Italy, but in 2002 Ficetola recorded the first reproduction case of Trachemys scripta elegans on the Po Delta on sympatric condition with an Emys orbicularis population. The population of Angitola represents one of the largest reproductive population of Europe and the most important for our country. In Italy Trachemys scripta elegans deposition in seminatural conditions takes place once a year at the end of June. We recorded for the first time that in our study area deposition takes place twice a year, as reported for the American populations: we think that the first event in April-May, with hatching in June and July, and the second event in July- August, with hatching in September-October. Some tropical Trachemys species tend to nest in open areas that receive direct sunlight for at least part of each day. Analysis of the use of vegetative cover in our study area revealed that Trachemys scripta elegans nests were not randomly distributed within the general area used for nesting, and it suggesting that females were actively selecting nesting sites. In fact the largest number of nests around the lake was found in areas with mixed vegetative cover, as reported for Trachemys callirostris in Colombia. Mixed vegetative cover might reduce thermal stress to the nesting females, as well as lower the detectability of nests to natural predators and human hunters. It has been reported that Trachemys nesting females prefer only dirt soil, but in our study area the largest number of nests in our study area were found in habitat with mixed soil type categories, these zones were characterized by heterogeneous granulometry that increase the ventilation of the nest and the humidity degree for hatching success. We investigated experimentally the occupation of basking sites thus providing a better knowledge on this behavioral pattern. During thermoregulation turtles of lake Angitola mainly bask along the emergent deadwood. Floating (thermoregulation on the water surface) is showed especially during the summer season. This population performs basking from April to October at different times of the day: for example during the cooler months the time of sunlight exposure increases and the basking behavior occurs during the hottest hours of the day. These results are also important for further evaluations on competition for occupation of basking places between this allocthonous specie and Emys orbicularis, our endangered European pond turtle. In fact as reported in literature that Trachemys scripta elegans requires less exposure time for thermoregulation than Emys orbicularis, and for this reason American slider turtle is the winning species in competition for basking sites in sympatric conditions. The invasion process of the Trachemys population inhabiting the lake of Angitola is at the second step, in fact we are in front of a self-sustaining and growing population. Moreover the local population of Emys orbicularis, historically present in the lake until the early 2000's, nowadays is probably extinct. In conclusion it is very important to complete echo-ethological investigations for better understanding the biology and ecology of this invader, and to provide a monitoring and controlling plans, and to define translocation and eradication plans, but this operations could be extremely difficult and more expansive. The results of this research were objects of a scientific paper and of same participation for congresses. Two more papers are in preparation.
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
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.
Effects of climate change on female reproductive fitness in rock sparrow petroniapetronia (Aves, Passeridae) breeding in the western alps
(2014-11-11) Storino, Pierpaolo; Cerra, Maria Carmela; Mingozzi, Antonio T.
Effetti del daidzein sul comportamento mnemonico attraverso le variazioni del sistema neurotensinergico e di fattori infiammatori in aree limbiche di criceti high fat diet
(2018-04-11) Fazzari, Gilda; Cerra, Maria Carmela; Canonaco, Marcello
In the past years, growing indications have pointed to food diets as major factors capable of conditioning physical-social states in humans as suggested by high-fat containing food sources which, despite their extremely "tasteful" properties, are responsible for marked morpho-structural alterations in critical brain areas for the regulation of not only psycho-cognitive behaviors but above all for nutritional parameters. It is already known that food consumption and action mechanisms implicated in energetic homeostasis are part of a complex neuronal circuit that when they are altered tend to account for increased body weight and consequently the development of obesity, regarded a chronic disease leading to different medical co-morbidities such as cardiovascular diseases (especially hypertension), dyslipidemia and diabetes type 2. From these effects plus the avoidance of applying drugs with numerous collateral alterations have directed a greater attention towards the production of "safer" drugs natural deriving vegetable extracts such as daidzein (DZ), a glucosidic isoflavone capable of mimicking estrogenic activities at the brain level, which supplied neuroprotective values against increased body weight, elevated feeding duration and diminished locomotor activity of high fat diet (HFD) hamsters (Mesocricetus auratus). This isoflavone also reduced anxiety-like behaviors in hyperlipidic animals as indicated by a greater time spent (p<0.01) in open arms of elevated plus maze (EPM) along with greater exploration (p<0.001) tendencies toward new objects of the novel object recognition (NOR) test. From a molecular point of view, DZ greatly protected the brain against neurodegeneration events as pointed out by few Amino Cupric Silver Stain granules in the hippocampus (HIP), hypothalamus (HTH) and amygdala (AMY) very likely via a diminished interaction of neurotensin receptor1 (anorexic neuropeptide; NTR1) GABAergic-leptin receptor levels in the latter two areas after the conditioned place preference (CPP) test. Contextually the recovered cognitive performances seemed to be tightly linked with reduced NTR1 expression levels in an ERβ manner for HIP after NOR test. In addition, such effects of DZ also strongly required increased levels of the antineuroinflammatory cytokine IL-10 that by reducing adenosine 5' monophosphate kinase (AMPK) and extracellular receptor kinase (ERK) widely improved cognitive together with exploratory behaviors. Overall, these first results supply important evidences on the neuroprotective values of DZ, which through NTR1 + IL-10 protective and repairing mechanisms of, aside the above limbic areas, also appetite-mediated brain centers known for their feeding, cognitive and endocrine functions, may surely comprise a good start for the introduction of novel therapeutic applications against obesity conditions.
Effetti dell’esposizione a breve termine a nonilfenolo etossilato sul fegato e sull’epidermide del Tritone italiano Lissotriton italicus
(2011) Biasone, Patrizia; Cerra, Maria Carmela; Tripepi, Sandro; Brunelli, Elvira
Effetti neuro-comportamentali del rame nei teleostei: ruolo dell'HSP90 e del sistema ORXergico
(2012-11-29) Zizza, Merylin; Cerra, Maria Carmela; Canonaco, Marcello; Facciolo, Rosa Maria
Tra i metalli, il rame (Cu2+), sebbene essenziale per il corretto metabolismo corporeo, può risultare un potente agente tossico in grado di promuovere pericolosi eventi nocivi, soprattutto nei pesci. Ad oggi, sono poche le informazioni sulla neurotossicità ramedipendente e le risposte attivate per la difesa e riparazione da tale tossicità. Su questi presupposti, nel presente lavoro sono stati investigati gli effetti del cloruro di rame (CuCl2), a diverse concentrazioni e tempi di esposizione, sia a livello comportamentale che neuronale nel teleosteo d’acqua dolce, Carassius carassius, e marino, Thalassoma pavo. Da un punto di vista molecolare, l’attenzione è stata indirizzata alle variazioni trascrizionali dell’Heat Shock Protein 90 (HSP90), chaperon con ruolo critico sia in condizioni fisiologiche che di stress. Alla luce di recenti evidenze che propongono il sistema orexinergico come cruciale nella coordinazione delle reazioni fisiologiche allo stress, è stata valutata anche la capacità dell’orexina-A (ORX-A), somministrata ogni giorno intraperitonealmente (10 ng/g peso corporeo) durante l’esposizione al Cu2+, di modulare gli effetti neuro-comportamentali di tale metallo nei suddetti teleostei. Il trattamento a breve termine (48h) con due concentrazioni di metallo, selezionate mediante screening preliminari in Carassius carassius (1.45 mg/L e 0.30 mg/L CuCl2) e Thalassoma pavo (1.07 mg/L e 0.25 mg/L CuCl2), ha causato evidenti alterazioni comportamentali. In particolare, il feeding è risultato notevolmente (p<0.001; p<0.01) ridotto, vs i controlli, in Carassius carassius e in Thalassoma pavo, rispettivamente. Nel primo pesce, la concentrazione di 1.45 mg/L ha causato anche una moderata (p<0.05) riduzione dello swimming, accompagnata da un simultaneo incremento del resting state. In modo analogo, in Thalassoma pavo, la riduzione dello swimming durante l’esposizione alla più bassa concentrazione, si è tradotta in un concomitante incremento del resting state. Nei teleostei marini, esposti a 1.07 mg/L di metallo, l’assenza di effetti significativi sul rest era dovuta alla comparsa di abnormal motor behaviors, caratterizzati da perdita di equilibrio e movimenti repentini ed improvvisi. In Carassius carassius tali atteggiamenti insorgevano solo moderatamente dopo 48h di esposizione alla alta concentrazione. Inoltre, durante l’esposizione, entrambi i teleostei mostravano una considerevole tendenza a nuotare verso la superficie (swimming towards surface). Accanto agli effetti sul comportamento, l’Amino Cupric Silver Stain ha anche mostrato segni di neurodegenerazione a carico dei neuroni, soprattutto nel nucleo laterale del telencefalo dorsale (Dl) degli esemplari esposti alle alte concentrazioni di contaminante. Parallelamente, l’ibridazione in situ ha fatto registrare nell’encefalo di Thalassoma pavo, trattato con la concentrazione più alta, un’up-regulation dell’HSP90 in differenti nuclei, come Dl (+87%). In Carassius carassius la risposta trascrizionale è stata invece meno evidente, con moderati incrementi dell’mRNA rinvenuti, ad esempio, nella valvola del cervelletto (VCe; +31%), in seguito a trattamento con la più alta concentrazione che causava anche moderate down-regulations a livello del telencefalo. E’ stato interessante notare che molte delle alterazioni comportamentali venivano ridotte dalla somministrazione di ORX-A, soprattutto a livello del feeding di entrambi i teleostei. In Carassius carassius si è potuto osservare, inoltre, una riduzione degli abnormal motor behaviors e dello swimming towards surface. Anche a livello neurodegenerativo, l’ORX-A è stata in grado di prevenire i danni indotti dal Cu2+, come nel Dl di Carassius carassius esposto alla più alta concentrazione. Dal punto di vista molecolare, l’ORX-A ha prevenuto la down-regulation indotta dal metallo in Dl, favorendo addirittura una moderata up-regulation del trascritto in TLo (+32%) di Carassius carassius esposto a 1.45 mg/L di CuCl2, rispetto ai controlli. Anche in Thalassoma pavo, il neuropeptide induceva una significativa up-regulation dell’espressione di HSP90, come nel nucleo laterale del telencefalo ventrale (Vl; +92%) durante esposizione alla concentrazione più bassa di CuCl2. Quando i pesci esposti al Cu2+ per 48h sono stati trasferiti in acqua priva di metallo, molti deficit neuro-comportamentali erano, almeno parzialmente, ripristinati. Inoltre, quasi tutti i nuclei encefalici di entrambi i teleostei, esposti alla più alta concentrazione, hanno mostrato incrementi significativi dell’mRNA per l’HSP90, sia rispetto al precedente trattamento che ai controlli. Alla luce dei dati ottenuti e in virtù del fatto che la bassa concentrazione aveva fatto rinvenire alterazioni neuro-comportamentali più lievi, in alcuni casi recuperabili, è stato interessante verificare gli effetti di questa stessa concentrazione in un trattamento cronico (21 giorni). Nel corso di tale trattamento, il feeding di Carassius carassius era drasticamente ridotto, rispetto ai controlli, a partire dal giorno 7 di esposizione mentre in Thalassoma pavo la riduzione diveniva elevata al giorno 14. A livello encefalico, si riscontrava una più estesa degenerazione che colpiva molti più campi neuronali, compreso il nucleo diffuso del lobo inferiore (NDLI). Al contempo, il trattamento cronico era responsabile di una generalizzata up-regulation dell’HSP90 in Thalassoma pavo e di un effetto trascrizionale sito-specifico in Carassius carassius. In quest’ultimo teleosteo, infatti, si riportavano down-regulations nel telencefalo (~-30%) e in NDLI (-55%), ed upregulations in TLo (+30%), VCe (+43%) e nel corpo del cervelletto (CCe; +52%). La somministrazione di ORX-A al 21 giorno, sebbene causasse un’attenuazione degli effetti del Cu2+ sul comportamento, non era però capace di ridurre i danni neuronali e, a livello trascrizionale, non influenzava in modo efficiente l’espressione dell’HSP90 Nel complesso, i risultati di questo lavoro di Dottorato forniscono importanti evidenze degli effetti neuro-comportamentali del Cu2+ in Carassius carassius e Thalassoma pavo, sottolineando il coinvolgimento dell’HSP90 nei meccanismi di protezione e riparazione innescati a livello encefalico. In aggiunta a ciò, per la prima volta, si suggerisce l’implicazione del sistema ORXergico nell’attivazione di risposte adattative allo stress indotto dal Cu2+, sia nei teleostei marini che d’acqua dolce
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
Espressione di sistemi di trasporto umani di membrana plasmatica in E.coli
(2014-03-26) Amelio, Linda; Cerra, Maria Carmela; Pochini, Lorena
In this work we studied the bacterial over-expression of two human transporters belonging the Organi Cation Trasportr Novel (OCTN) protein family. This family includes the mammalian plasma membrane transporters OCTN1, OCTN2 and OCTN3, which share more than 66 % identity with each other. Defects of OCTN1 and OCTN2 are associated with the Crohn disease and the primary carnitine deficiency, respectively. The molecular and functional studies of these transport systems are hampered by the difficulties in bacterial overexpression and solubilization. Thus, the transporters have been functionally characterized in cell systems like oocytes expressing the protein at low level (Lahjouji et al 2001; Tamai et al 1997) or in proteoliposomes reconstituted with the protein extracted from kidney cells (Pochini et al 2004). On the one hand the OCTN2 has been well characterized. On the other hand many discrepancies about the function of OCTN1 have been reported (Lahjouji et al 2001; Tamai et al 1997; Yabuuchi et al 1999). OCTN2 catalyzes a sodium-dependent antiport of carnitine with itself or carnitine derivatives. It was found that some drugs, such as omeprazole, can interact with the transporter (Pochini et al 2009). However, so far, no examples of strategies of large scale over-expression and/or purification of these proteins have been reported and, hence, no structural data are available. Here, the first successful procedures for the large scale over-expression and purification of the transporters are described. The hOCTN1 cDNA, previous obtained from primary human fibroblasts, was cloned in different plasmids, and the best over-expression was obtained with the pH6EX3 in RosettaGami2(DE3)pLysS strain. The expressed protein results as a 6-His tagged protein. Also the hOCTN2 cDNA was cloned in several plasmids but the recombinant protein was obtained only using pET41 in E.coli 5 Rosetta(DE3)pLysS. By this strategy, the OCTN2 was expressed as GST-6His tagged protein. The over-expressed OCTN1 and OCTN2 had an apparent molecular mass of 58 kDa and 87 kDa, respectively, calculated on the basis of SDS-page, and were both collected in the insoluble fraction. For purification strategy, the two over-expressed transporters were washed with a buffer containing sarkosyl and urea and applied on different Ni2+-chelating chromatography columns. The protein OCTN1 was eluted with a buffer containing 50 mM imidazole and 0.1 % Triton X-100, in quantitiy of 3 mg per litre of cell culture, and then incubated with -mercaptoethanol, to strongly reduce the disulphide bonds; by this way, a different migration on SDS-page to exact molecular weight was observed. The protein OCTN2, previous to be applied on a chromatography column, was treated with DTE and then eluted in the same buffer used for OCTN1 but at different pH. About 0.2 mg of protein per liter of cell culture were obtained. OCTN2 was then, incubated with thrombin 0.1U/l at 25°C and after 4 hours we observed the separation of hOCTN2 and GST fusion tag on SDS-page.
Functional cooperation between GPER and AHR toward breast cancer progression
(2019-04-11) Cirillo, Francesca; Cerra, Maria Carmela; Maggiolini, Marcello
The cytochrome P450 1B1 (CYP1B1) is a heme-thiolate monooxygenase involved in both estrogen and environmental contaminants metabolism. For instance, CYP1B1 catalyzes the hydroxylation of 17-β estradiol (E2) leading to the production of 4-hydroxyestradiol that may act as a potent carcinogenic agent. In addition, CYP1B1 is overexpressed in different tumors including breast cancer. In this scenario, it is worth mentioning that CYP1B1 expression is triggered by estrogens through the estrogen receptor (ER)α in breast cancer cells. In the present study, we evaluated whether the G protein estrogen receptor namely GPER may provide an alternate route toward the expression and function of CYP1B1 in ER-negative breast cancer cells, in cancer-associated fibroblasts (CAFs) obtained from breast cancer patients, in CAFs derived from a cutaneous metastasis of an invasive mammary ductal carcinoma and in breast tumor xenografts. Our results show that GPER along with the EGFR/ERK/c-Fos transduction pathway can lead to CYP1B1 regulation through the involvement of a half-ERE sequence located within the CYP1B1 promoter region. As a biological counterpart, we found that both GPER and CYP1B1 mediate growth effects in vitro and in vivo. Altogether, these data suggest that estrogens in ER-negative cell contexts may engage the alternate GPER signaling toward CYP1B1 regulation. CYP1B1 is a well-known target gene of the aryl hydrocarbon receptor (AHR) that may be activated by the carcinogenic pollutant 3-methylcholanthrene (3MC). Hence, we aimed to provide novel insights into the molecular mechanisms by which 3MC and E2 may activate a cross talk between AHR and GPER transduction pathways leading to the stimulation of breast cancer cells and CAFs. In particular, our results demonstrate that 3MC and E2 trigger the EGFR/ERK/c-Fos signalling through both AHR and GPER toward the up-regulation of CYP1B1 and cyclin D1 as well as the stimulation of growth responses. Altogether, the present findings suggest that a functional interaction between AHR and GPER may occur toward breast cancer progression
Gene expression patterns and stress response in the copepod Calanus helgolandicus
(2011) Lauritano, Chiara; Cerra, Maria Carmela; Branno, Margherita; Ianora, Adrianna; Procaccini, Gabriele
Diatoms and dinoflagellates are dominant photosynthetic organisms in the world‟s oceans and are considered essential in the transfer of energy through marine food chains. However, these unicellular organisms produce secondary metabolites such as products deriving from the oxidation of fatty acids collectively termed oxylipins (including polyunsaturated aldehydes or PUAs; by diatoms) or potent neurotoxins (brevetoxins; by dinoflagellates). It is often assumed that harmful algae toxins are grazing deterrents to discourage zooplankton grazers from eating these algae. Some laboratory studies have suggested that some toxic algae are either not eaten by various grazers or that grazers ingesting toxic algae suffer adverse effects such as reduced feeding rates, diminished reproductive success, behavioral modification or increased mortality (Cohen et al., 2007, Kubanek et al., 2007; Prince et al., 2006). The aim of this thesis was to study in the copepod Calanus helgolandicus the effects of toxic diets at the molecular level. Expression level analyses by the sensible technique reverse transcription-quantitative polymerase chain reaction (RT-qPCR) allowed the study of specific genes of interest (GOI) which are known to have a primary role in generic stress responses, defense systems (e.g. aldehyde, free fatty acid and free radical detoxification) or apoptosis regulation in other organisms, from humans to marine organisms (Bouraoui, et al., 2009; Einsporn, et al., 2009; Hasselberg, et al., 2004; Kim, et al., 2008; Olsvik, et al., 2009; Salazar-Medina, et al., 2010; Snyder, 2000; Vasiliou, et al., 2004; Wan, et al., 2011). The GOI analyzed were two heat shock proteins (HSP70 and HSP40), six Aldehyde dehydrogenases (ALDH2, ALDH3, ALDH6, ALDH7, ALDH8, ALDH9), Cytochrome P450-4 (CYP4), Catalase (CAT), Superoxide Dismutase (SOD), Glutathione S-Transferase (GST), Glutathione Synthase (GSH-S), Inhibitor of Apoptosis Protein (IAP), Cell Cycle and Apoptosis Regulatory 1Protein (CARP), Cellular Apoptosis Susceptibility Protein (CAS), actin (ACT) and Alpha and Beta tubulins (ATUB and BTUB). These GOI were analyzed in various experimental conditions: copepods exposed to algae which produce or do not produce toxic metabolites, including dinoflagellates (Prorocentrum minimum, Rhodomonas baltica or Karenia brevis) and diatoms (Chaetoceros socialis and Skeletonema marinoi), during field or laboratory experiments. In addition, the effect of the oxylipin producing diatom Skeletonema marinoi has been tested on two different C. helgolandicus populations: the Mediterranean population collected in the Adriatic Sea and the Atlantic population collected in the English Channel. According to the results obtained, expression levels of the specific GOI changed depending on the tested algae, times of exposure, copepod population analyzed and field/laboratory experiments. Gene expression level patterns in the different experimental conditions tested may help to understand the copepod response to stressful conditions. The identification of new genes, for example using cDNA libraries or new generation sequencing, and the application of new tools, such as functional proteomic approaches, may allow for a more comprehensive overview of how copepods respond to specific stressors in the laboratory, but also to predict the response under natural environmental conditions and the effects of these responses on higher trophic levels.