Publications (33) View all
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Article: Bacterial diversity of traditional Fossa (pit) cheese and its ripening environment
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ABSTRACT: Bacterial diversity of Fossa (pit) cheese during ripening and its related environment was investigated by culture-dependent and -independent methods. The dominant clones during cheese ripening, among 244 16S rRNA genes (rDNA), belonged to Firmicutes (99%) mainly affiliated with Lactococcus lactis and Streptococcus thermophilus starter species. Sequencing of 16S rDNA from 171 isolates cultured in M17 and MRS media showed an increasing occurrence of non-starter lactic acid bacteria (NSLAB) during ripening such as Lactobacillus plantarum, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus fermentum, Lactobacillus rhamnosus. A greater diversity of NSLAB was found in the isolates than in the clone library. L. plantarum was the dominant species in Fossa cheese (42.9%). Bacterial species identified from pit air and surface samplings (271 clones, 63 strains) revealed 40 different operational taxonomic units belonging to seven taxonomic affiliations: Actinobacteria, Firmicutes, Bactereoidetes, a-, b-, g-, d-Proteobacteria; however, no evidence for environmental strains within the Fossa cheese was found.International Dairy Journal 01/2012; 23:62-67. · 2.40 Impact Factor -
Article: Reactive oxygen species in skeletal muscle signaling.
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ABSTRACT: Generation of reactive oxygen species (ROS) is a ubiquitous phenomenon in eukaryotic cells' life. Up to the 1990s of the past century, ROS have been solely considered as toxic species resulting in oxidative stress, pathogenesis and aging. However, there is now clear evidence that ROS are not merely toxic species but also-within certain concentrations-useful signaling molecules regulating physiological processes. During intense skeletal muscle contractile activity myotubes' mitochondria generate high ROS flows: this renders skeletal muscle a tissue where ROS hold a particular relevance. According to their hormetic nature, in muscles ROS may trigger different signaling pathways leading to diverging responses, from adaptation to cell death. Whether a "positive" or "negative" response will prevail depends on many variables such as, among others, the site of ROS production, the persistence of ROS flow or target cells' antioxidant status. In this light, a specific threshold of physiological ROS concentrations above which ROS exert negative, toxic effects is hard to determine, and the concept of "physiologically compatible" levels of ROS would better fit with such a dynamic scenario. In this review these concepts will be discussed along with the most relevant signaling pathways triggered and/or affected by ROS in skeletal muscle.Journal of signal transduction. 01/2012; 2012:982794. -
Article: Morphofunctional and Biochemical Approaches for Studying Mitochondrial Changes during Myoblasts Differentiation.
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ABSTRACT: This study describes mitochondrial behaviour during the C2C12 myoblast differentiation program and proposes a proteomic approach to mitochondria integrated with classical morphofunctional and biochemical analyses. Mitochondrial ultrastructure variations were determined by transmission electron microscopy; mitochondrial mass and membrane potential were analysed by Mitotracker Green and JC-1 stains and by epifluorescence microscope. Expression of PGC1α, NRF1α, and Tfam genes controlling mitochondrial biogenesis was studied by real-time PCR. The mitochondrial functionality was tested by cytochrome c oxidase activity and COXII expression. Mitochondrial proteomic profile was also performed. These assays showed that mitochondrial biogenesis and activity significantly increase in differentiating myotubes. The proteomic profile identifies 32 differentially expressed proteins, mostly involved in oxidative metabolism, typical of myotubes formation. Other notable proteins, such as superoxide dismutase (MnSOD), a cell protection molecule, and voltage-dependent anion-selective channel protein (VDAC1) involved in the mitochondria-mediated apoptosis, were found to be regulated by the myogenic process. The integration of these approaches represents a helpful tool for studying mitochondrial dynamics, biogenesis, and functionality in comparative surveys on mitochondrial pathogenic or senescent satellite cells.Journal of aging research 01/2011; 2011:845379. -
Article: Hyphal and cytoskeleton polarization in Tuber melanosporum: a genomic and cellular analysis.
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ABSTRACT: Filamentous polarized growth involves a series of events including polarization of the cytoskeleton to selected growth sites, and the transport of secretory vesicles containing the components required for growth. The availability of fungal genome sequences has recently led to the identification of a large number of proteins involved in these processes. We have explored the Tuber melanosporum genome sequence by searching for homologs of genes known to play crucial roles in the morphogenesis and cell polarity of yeasts and filamentous fungi. One hundred and forty-nine genes have been identified and functionally grouped according to the deduced amino acid sequences (44 genes involved in cell polarity/morphogenesis, 39 belonging to the actin cytoskeleton and 66 involved in membrane dynamics, septation and exocytosis). A detailed gene annotation has shown that most components of the cell polarity machinery, morphogenesis and cytoskeleton found in yeasts and filamentous fungi are conserved, although the degree of similarity varies from strong to weak. Microscopic analysis of quick-frozen truffle hyphae detected the characteristic subcellular components of the hyphal tip in septate filamentous fungi, while transcript profiles revealed a moderately variable pattern during the biological cycle.Fungal Genetics and Biology 12/2010; 48(6):561-72. · 3.74 Impact Factor -
Article: A combined morphologic and molecular approach for characterizing fungal microflora from a traditional Italian cheese (Fossa cheese)
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ABSTRACT: Phenotypic and genotypic methods were used to identify filamentous fungi that characterize traditional Italian Fossa cheese and its ripening environment. After ageing for 60 days at a dairy, it was ripened for an additional three months in a pit. In the fully ripened cheese, moulds ranged from 3 to 3.4 log cfu g�1 and Penicillium was the prevalent species. Pit environmental fungi ranged from 530 to 750 cfum�3 (air) and from 130 to 340 cfu cm�2 (surfaces). The dominant pit strains were Alternaria spp., Aspergillus spp., Cladosporium spp. and Penicillium spp. Phylogenetic analyses of 18S rRNA gene and ITS1-5.8S-ITS2 regions highlighted Penicillium camemberti, Aspergillus nidulans and Aspergillus versicolor as traceable species occurring in both the cheese and pit environment, suggesting their involvement in the development of typical Fossa cheese characteristics. This approach may be used for the identification of microflora on other cheese varieties to better understand the fungal contribution in cheese ripening.International Dairy Journal 01/2010; 20:465-471. · 2.40 Impact Factor
