Unraveling the role of microRNA/isomiR network in multiple primary melanoma pathogenesis

Malignant cutaneous melanoma (CM) is a potentially lethal form of skin cancer whose worldwide incidence has been constantly increasing over the past decades. During their lifetime, about 8% of CM patients will develop multiple primary melanomas (MPMs), usually at a young age and within 3 years from the first tumor/diagnosis. With the aim of improving our knowledge on MPM biology and pathogenesis, we explored the miRNome of 24 single and multiple primary melanomas, including multiple tumors from the same patient, using a small RNA-sequencing approach. From a supervised analysis, 22 miRNAs were differentially expressed in MPM compared to single CM, including key miRNAs involved in epithelial–mesenchymal transition. The first and second melanoma from the same patient presented a different miRNA profile. Ten miRNAs, including miR-25-3p, 149-5p, 92b-3p, 211-5p, 125a-5p, 125b-5p, 205-5p, 200b-3p, 21-5p, and 146a-5p, were further validated in 47 single and multiple melanoma samples. Pathway enrichment analysis of miRNA target genes revealed a more differentiated and less invasive status of MPMs compared to CMs. Bioinformatic analyses at the miRNA isoform (isomiR) level detected a panel of highly expressed isomiRs belonging to miRNA families implicated in human tumorigenesis, including miR-200, miR-30, and miR-10 family. Moreover, we identified hsa-miR-125a-5p|0|−2 isoform as tenfold over-represented in melanoma than the canonical form and differentially expressed in MPMs arising in the same patient. Target prediction analysis revealed that the miRNA shortening could change the pattern of target gene regulation, specifically in genes implicated in cell adhesion and neuronal differentiation. Overall, we provided a putative and comprehensive characterization of the miRNA/isomiR regulatory network of MPMs, highlighting mechanisms of tumor development and molecular features differentiating this subtype from single melanomas.Subject terms: Small RNAs, Melanoma     

Laccase-mediated oxidation of natural glycosides

Regioselective oxidations of the primary OH's of natural glycosides (thiocolchicoside, colchicoside, amygdalin, asiaticoside, ginsenoside R_E) have been performed on a preparative scale by exploiting the laccase–2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) methodology. The influence of water-miscible organic cosolvents on the stability and activity of a laccase from Trametes pubescens has been investigated. The enzyme has been covalently linked to Eupergit C250L and its performances evaluated. The recovered immobilized enzyme catalyzed several oxidative cycles of thiocolchicoside, without showing significant loss of activity.     

A molecular dynamics strategy for CSαβ peptides disulfide-assisted model refinement

Many cysteine-stabilized antimicrobial peptides from a variety of living organisms could be good candidates for the development of anti-infective agents. In the absence of experimentally obtained structural data, peptide modeling is an essential tool for understanding structure–activity relationships and for optimizing the bioactive moieties. Focusing on cysteine-rich peptide structures, we reproduced the case of structure predictions in the so-called midnight zone. We developed our protocol on a training set derived by clustering the available cysteine-stabilized αβ (CSαβ) structures in nine different representative families and tested it on peptides randomly selected from each family. Starting from draft models, we tested a structure-based disulfide predictor and we used cysteine distances as constraints during molecular dynamics. Finally, we proposed an analysis for final structure selection. Accordingly, we obtained a mean root mean square deviation improvement of 21% for the test set. Our findings demonstrate that it is possible to predict the network of disulfide bridges in cysteine-stabilized peptides and to use this result to improve the accuracy of structural predictions. Finally, we applied the methods to predict the structure of royalisin, a cysteine-rich peptide with unknown structure.     

Integrating three comprehensive data sets shows that mitochondrial DNA variation is linked to species traits and paleogeographic events in European butterflies

Understanding the dynamics of biodiversity, including the spatial distribution of genetic diversity, is critical for predicting responses to environmental changes, as well as for effective conservation measures. This task requires tracking changes in biodiversity at large spatial scales and correlating with species functional traits. We provide three comprehensive resources to understand the determinants for mitochondrial DNA differentiation represented by (a) 15,609 COI sequences and (b) 14 traits belonging to 307 butterfly species occurring in Western‐Central Europe and (c) the first multi‐locus phylogenetic tree of all European butterfly species. By applying phylogenetic regressions we show that mitochondrial DNA spatial differentiation (as measured with G_ST, G′_ST, D and D_ST) is negatively correlated with species traits determining dispersal capability and colonization ability. Thanks to the high spatial resolution of the COI data, we also provide the first zoogeographic regionalization maps based on intraspecific genetic variation. The overall pattern obtained by averaging the spatial differentiation of all Western‐Central European butterflies shows that the paradigm of long‐term glacial isolation followed by rapid pulses of post‐glacial expansion has been a pervasive phenomenon in European butterflies. The results and the extensive data sets we provide here constitute the basis for genetically‐informed conservation plans for a charismatic group in a continent where flying insects are under alarming decline.     

Biomechanical and metabolic responses to seat-tube angle variation during cycling in tri-athletes

One of the most physically demanding parts of triathlon is the transition from cycling to running. Many tri-athletes believe that increasing seat-tube angle (STA) can bring advantages in the following running part. The aim of this study was to evaluate the effects of inverting the support of the seat, for increasing STA, on the metabolic response and on the muscle activation pattern, maintaining a controlled kinematic. Moreover, a muscle-skeletal model was applied to evaluate the hypothesis that increasing STA changes force-producing capabilities of muscles crossing the hip.Ten tri-athletes cycled at two different power levels and with two different STA’s. Gas exchange data, kinematics and surface electromyography (sEMG) were acquired during the tests. sEMG was measured from eight muscles of the right side of the body. A model of muscle mechanics and energy expenditure was applied to estimate variations of force production capabilities and muscle energy consumption between the two STA configurations.Inverting the support of the seat showed no significant effects on kinematic, Oxygen consumption, muscle activations and muscle power production capabilities. Nevertheless, an interesting advantage can be the tendency to less activate gastrocnemius and biceps femoris: this could lead to minor muscle fatigue during the following running phase.     

The Polycomb group protein MEDEA controls cell proliferation and embryonic patterning in Arabidopsis

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Isothermal and non-isothermal bioreactors in the detoxification of waste waters polluted by aromatic compounds by means of immobilised laccase from Rhus vernicifera

Laccase from Rhus vernicifera was immobilised on a nylon membrane chemically grafted with glycidyl methacrylate (GMA). Hexamethylenediamine (HMDA) and glutaraldehyde (GLU) were used as spacer and bifunctional coupling agent, respectively. Quinol was used as substrate.

To know how the immobilisation procedures affected the enzyme reaction rate the catalytic behaviour of soluble and insoluble laccase was studied under isothermal conditions as a function of pH, temperature and substrate concentration. From these studies, two main singularities emerged from the experimental data: (i) the narrower pH-activity profile of the insoluble enzyme in comparison to that of the soluble counterpart; (ii) the increase of the affinity of the immobilised enzyme for its substrate.

The behaviour of the catalytic membrane was also studied in a non-isothermal bioreactor as a function of substrate concentration and size of the applied transmembrane temperature difference. It was found that, under non-isothermal conditions and keeping constant the average temperature of the bioreactor, the enzyme reaction rate linearly increases with the increase of the temperature difference. These results have been discussed in the frame of reference of the process of thermodialysis driving thermodiffusive transmembrane substrate fluxes, which add to the diffusive ones.

The advantages of the catalytic process carried out under non-isothermal conditions have been thrown in relief through the evaluation of the reduction of the production times and of the percentage increases of the enzyme activity.