Assessment of the population structure and temporal changes in spatial dynamics and genetic characteristics of the Atlantic bluefin tuna under a fishery independent framework.

As a large and long-lived species with high economic value, restricted spawning areas and short spawning periods, the Atlantic bluefin tuna (BFT; Thunnus thynnus) is particularly susceptible to over-exploitation. Although BFT have been targeted by fisheries in the Mediterranean Sea for thousands of years, it has only been in these last decades that the exploitation rate has reached far beyond sustainable levels. An understanding of the population structure, spatial dynamics, exploitation rates and the environmental variables that affect BFT is crucial for the conservation of the species. The aims of this PhD project were 1) to assess the accuracy of larval identification methods, 2) determine the genetic structure of modern BFT populations, 3) assess the self-recruitment rate in the Gulf of Mexico and Mediterranean spawning areas, 4) estimate the immigration rate of BFT to feeding aggregations from the various spawning areas, and 5) develop tools capable of investigating the temporal stability of population structuring in the Mediterranean Sea. Several weaknesses in modern morphology-based taxonomy including demographic decline of expert taxonomists, flawed identification keys, reluctance of the taxonomic community to embrace advances in digital communications and a general scarcity of modern user-friendly materials are reviewed. Barcoding of scombrid larvae revealed important differences in the accuracy of the taxonomic identifications carried out by different ichthyoplanktologists following morphology-based methods. Using a Genotyping-by-Sequencing a panel of 95 SNPs was developed and used to characterize the population structuring of BFT and composition of adult feeding aggregations. Using novel molecular techniques, DNA was extracted from bluefin tuna vertebrae excavated from late iron age, ancient roman settlements Byzantine-era Constantinople and a 20th century collection. A second panel of 96 SNPs was developed to genotype historical and modern samples in order to elucidate changes in population structuring and allele frequencies of loci associated with selective traits.

Well-being, distress and health status in a population of adolescent students

The present work explores the psychosocial issues emerging from a large cross-sectional study aimed to assess the prevalence, clinical manifestations, and psychosocial correlates of hyperandrogenism in a population of Italian high school students. Participants were 1804 adolescents, aged between 15 and 19 years, who volunteered to fill in a package of self-report questionnaires (including the Psychosocial Index, the Symptom Questionnaire and Ryff’s Psychological Well-Being scales for the assessment of psychological aspects) and undergo a comprehensive physical examination. Significant gender differences were found with regard to psychological distress, with females reporting higher scores compared with males, but not on well-being dimensions. The relationships of well-being to distress were found to be complex. Although inversely associated, well-being and ill-being appeared to be distinct domains of mental functioning. The evaluation of the moderating effects of well-being in the association between stress and psychological distress indicated that well-being may act as a protective factor, contributing to less pronounced psychological distress as stress levels increased. Higher rates of somatic complaints were found among current smokers. However, substance use (i.e., smoking and drug use) was also found to be positively associated with some well-being dimensions. A considerable number of participants were found to present with disordered eating symptoms, particularly females, and associated higher stress levels and lower quality of life. Sport activities were found to favourably affect psychological health. As to clinical signs of hyperandrogenism, a significant impairment in psychosocial functioning was found among females, whereas no effects on psychological measures could be detected among males. Subgroups of adolescents with distinct clinical and psychological characteristics could be identified by means of cluster analysis. The present study provides new insights into better understanding of the complex relationships between well-being, distress and health status in the adolescent population, with important clinical implications.

Simkania negevensis: clinical and laboratory studies in the population of hemodialized and kidney transplanted patients.

Simkania negevensis is a bacterium belonging to the order Chlamydiales but with certain biological characteristics different from those of chlamydia, according to which it was classified in the family Simkaniaceae. It is widespread in the environment, due to its ability to survive in amoebae also in phase cystic, for which it was hypothesized a possible transmission after contact with water in which they are present amoebae. So far it is known its role in diseases of the lower respiratory tract, such as childhood bronchiolitis and pneumonia in adults of the community, following its transmission through infected aerosols. A recent American study showed, by PCR, a high prevalence of S. negevensis in patients with lung transplant than other transplant recipients, assuming an association between the presence of the bacterium in these patients, and transplant rejection, were more frequent in lung transplant recipients infected compared to uninfected. There are no data so far analyzed in Italy relative to the population of dialysis and kidney transplant recipients relative to simkania negevensis why this study was undertaken in order to start a specific location and evaluate the scientific implications. Because its ability to assume persistent forms of infection, which may lead to a prolonged inflammatory response, Simkania negevensis, similar to other persistent bacteria or viruses, may be ivolved in pathologic complication. Sn may be a factor in graft rejection in mmunesuppressed lung transplant recipients, and further studies are planned to explore the posible association of Sn infections with various in vivo pathologies.