Metodi molecolari nello studio della variabilità genetica di Tuber borchii

Tuber borchii (Ascomycota, order Pezizales) is highly valued truffle sold in local markets in Italy. Despite its economic importance, knowledge on its distribution and population variation is scarce. The objective of this work was to investigate the evolutionary forces shaping the genetic structure of this fungus using coalescent and phylogenetic methods to reconstruct the evolutionary history of populations in Italy. To assess population structure, 61 specimens were collected from 11 different Provinces of Italy. Sampling was stratified across hosts and habitats to maximize coverage in native oak and pine stands and both mychorrizae and fruiting bodies were collected. Samples were identified considering anatomo-morphological characters. DNA was extracted and both multilocus (AFLP) and single-locus (18 loci from rDNA, nDNA, and mtDNA) approaches were used to look for polymorphisms. Screening AFLP profiles, both Jaccard and Dice coefficients of similarity were utilized to transform binary matrix into a distance matrix and then to desume Neighbour-Joining trees. Though these are only preliminary examinations, phylogenetic trees were totally concordant with those deriving from single locus analyses. Phylogenetic analyses of the nuclear loci were performed using maximum likelihood with PAUP and a combined phylogenetic inference, using Bayesian estimation with all nuclear gene regions, was carried out. To reconstruct the evolutionary history, we estimated recurrent migration, migration across the history of the sample, and estimated the mutation and approximate age of mutations in each tree using SNAP Workbench. The combined phylogenetic tree using Bayesian estimation suggests that there are two main haplotypes that are difficult to be differentiated on the basis of morphology, of ecological parameters and symbiontic tree. Between these two lineages, that occur in sympatry within T. borchii populations, there is no evidence of recurrent migration. However, migration over the history of the sample was asymmetrical suggesting that isolation was a result of interrupted gene flow followed by range expansion. Low levels of divergence between the haplotypes indicate that there are likely to be two cryptic species within the T. borchii population sampled. Our results suggest that isolation between populations of T. borchii could have led to reproductive isolation between two lineages. This isolation is likely due to sympatric speciation caused by a multiple colonization from different refugia or a recent isolation. In attempting to determinate whether these haplotypes represent separate species or a partition of the same species we applied Biological and Mechanistic species Concepts. Notwithstanding, further analyses are necessary to evaluate if selection favoured premating or post-mating isolation

Selection of a set of specific primers for the identification of Tuber rufum: a truffle species of high genetic variability

Tuber rufum is a truffle widely distributed throughout Europe, which forms mycorrhizal associations with numerous species of broadleaf and coniferous trees. The possibility of T. rufum contamination in commercial truffle-infected plants makes its detection important. To facilitate the identification of T. rufum from mycorrhiza and fruitbodies, species-specific primers were designed and tested. To overcome the high intraspecific genetic variability within the internal transcribed spacer (ITS) regions of T. rufum, as demonstrated by phylogenetic analysis, two forward primers, Ru1f and Ru2f, located on the ITS1 region were designed to be used in concert with the reverse primer ITS4. Only T. rufum was amplified with this primer combination, while DNA of Tuber magnatum, Tuber brumale, Tuber maculatum, Tuber borchii, Tuber excavatum and Tuber melanosporum was not. These primers give a specific amplicon ranging between 566 and 572 bp and are able to discriminate between T. rufum, T. borchii and T. magnatum in multiplex PCR. In addition, T. rufum-specific amplicons were obtained from both spore suspensions and mycorrhiza by direct PCR. Tuber rufum mycorrhiza obtained in the greenhouse using mycelial inoculation techniques had morphological features similar to those of other species of Tuber, stressing the importance of molecular tools for their identification

A prospective cohort analysis of the prevalence and predictive factors of delayed discharge after laparoscopic cholecystectomy in Italy: the DeDiLaCo Study

Background: The concept of early discharge ≤24 hours after Laparoscopic Cholecystectomy (LC) is still doubted in Italy. This prospective multicentre study aims to analyze the prevalence of patients undergoing elective LC who experienced a delayed discharge >24 hours in an extensive Italian national database and identify potential limiting factors of early discharge after LC. Methods: This is a prospective observational multicentre study performed from January 1, 2021 to December 31, 2021 by 90 Italian surgical units. Results: A total of 4664 patients were included in the study. Clinical reasons were found only for 850 patients (37.7%) discharged >24 hours after LC. After excluding patients with nonclinical reasons for delayed discharge >24 hours, 2 groups based on the length of hospitalization were created: the Early group (≤24 h; 2414 patients, 73.9%) and the Delayed group (>24 h; 850 patients, 26.1%). At the multivariate analysis, ASA III class ( P <0.0001), Charlson's Comorbidity Index (P=0.001), history of choledocholithiasis (P=0.03), presence of peritoneal adhesions (P<0.0001), operative time >60 min (P<0.0001), drain placement (P<0.0001), pain ( P =0.001), postoperative vomiting (P=0.001) and complications (P<0.0001) were independent predictors of delayed discharge >24 hours. Conclusions: The majority of delayed discharges >24 hours after LC in our study were unrelated to the surgery itself. ASA class >II, advanced comorbidity, the presence of peritoneal adhesions, prolonged operative time, and placement of abdominal drainage were intraoperative variables independently associated with failure of early discharge