Correlation between insulin resistance and treatment-resistant acne

Physiologically during puberty and adolescence, when juvenile acne usually appears, the response to a glucose load is increased if compared to the one observed in adult and at pre-pubertal age, while insulin sensitivity is reduced. Insulin is a hormone that acts at different levels along the axis which controls the sex hormones. It increases the release of LH and FSH by pituitary gland, stimulates the synthesis of androgens in the gonads and stimulates the synthesis of androgenic precursors in adrenal glands. Finally, it acts in the liver by inhibiting the synthesis of Sex Hormone Binding Globulin (SHBG). Insulin is also able to act directly on the production of sebum and amplify the effects of Iinsulin Growth Factor-1 in the skin, inhibiting the synthesis of its binding protein (IGF Binding Protein-1). In female subjects with acne and Polycystic Ovary Syndrome (PCOS) insulin resistance is a well known pathogenetic factor, while the relationship between acne and insulin resistance has been poorly investigated in males so far. The purpose of this study is to investigate the correlation between insulin resistance and acne in young males who do not respond to common therapies. Clinical and biochemical parameters of glucose, lipid metabolism, androgens and IGF-1 were evaluated. Insulin resistance was estimated by Homeostasis Model assessment (HOMA-IR) and Oral Glucose Tolerance Test was also performed. We found that subjects with acne had higher Sistolic and Diastolic Blood Pressure, Waist/Hip Ratio, Waist Circumference, 120' OGTT serum insulin and serum IGF-1 and lower HDL-cholesterol than subjects of comparable age and gender without acne. The results thus obtained confirmed what other authors have recently reported about a metabolic imbalance in young males with acne. Furthermore, these results support the hypothesis that insulin resistance might play an important role in the pathogenesis of treatment-resistant acne in males.

Molecular strategies for genetic diversity analysis and development of markers linked to resistance traits in apple

The goal of many plant scientists’ research is to explain natural phenotypic variation in term of simple changes in DNA sequence. DNA-based molecular markers are extensively used for the construction of genome-wide molecular maps and to perform genetic analysis for simple and complex traits. The PhD thesis was divided into two main research lines according to the different approaches adopted. The first research line is to analyze the genetic diversity in an Italian apple germplasm collection for the identification of markers tightly linked to targeted genes by an association genetic method. This made it possible to identify synomym and homonym accessions and triploids. The fruit red skin color trait has been used to test the reliability of the genetic approaches in this species. The second line is related to the development of molecular markers closely linked to the Rvi13 and Rvi5 scab resistance genes, previously mapped on apple’s chromosome 10 and 17 respectively by using the traditional linkage mapping method. Both region have been fine-mapped with various type of markers that could be used for marker-assisted selection in future breeding programs and to isolate the two resistance genes.

Computational resources for structural and metagenomic characterization of functions in bacteria and bacterial communities. Antimicrobial resistance, pathways for xenobiotic degradation and relationship between gut microbiome and ageing.

Prokaryotic organisms are one of the most successful forms of life, they are present in all known ecosystems. The deluge diversity of bacteria reflects their ability to colonise every environment. Also, human beings host trillions of microorganisms in their body districts, including skin, mucosae, and gut. This symbiosis is active for all other terrestrial and marine animals, as well as plants. With the term holobiont we refer, with a single word, to the systems including both the host and its symbiotic microbial species. The coevolution of bacteria within their ecological niches reflects the adaptation of both host and guest species, and it is shaped by complex interactions that are pivotal for determining the host state. Nowadays, thanks to the current sequencing technologies, Next Generation Sequencing, we have unprecedented tools for investigating the bacterial life by studying the prokaryotic genome sequences. NGS revolution has been sustained by the advancements in computational performance, in terms of speed, storage capacity, algorithm development and hardware costs decreasing following the Moore’s Law. Bioinformaticians and computational biologists design and implement ad hoc tools able to analyse high-throughput data and extract valuable biological information. Metagenomics requires the integration of life and computational sciences and it is uncovering the deluge diversity of the bacterial world. The present thesis work focuses mainly on the analysis of prokaryotic genomes under different aspects. Being supervised by two groups at the University of Bologna, the Biocomputing group and the group of Microbial Ecology of Health, I investigated three different topics: i) antimicrobial resistance, particularly with respect to missense point mutations involved in the resistant phenotype, ii) bacterial mechanisms involved in xenobiotic degradation via the computational analysis of metagenomic samples, and iii) the variation of the human gut microbiota through ageing, in elderly and longevous individuals.