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Semaphorins are cell surface and/or soluble signals that exert an inhibitory control on axon guidance. Sema3A, the vertebrate-secreted semaphorin, binds to neuropilin-1, which together with plexins constitutes the functional receptor. To verify whether Sema3A is produced by white adipocytes and, in that case, to detect its targets in white adipose tissue, we studied the cell production and tissue distribution of Sema3A and neuropilin-1 in rat retroperitoneal and epididymal adipose depots. Sema3A and neuropilin-1 were detected in these depots by Western blotting. The immunohistochemical results showed that Sema3A is produced in, and possibly secreted by, smooth muscle cells of arteries and white adipocytes. Accordingly, neuropilin-1 was found on perivascular and parenchymal nerves. Such a pattern of distribution is in line with a role for secreted Sema3A in the growth and plasticity of white adipose tissue nerves. Indeed, after fasting, when white adipocytes are believed to be overstimulated by noradrenaline and rearrangement of the parenchymal nerve supply may occur, adipocytic expression of Sema3A is reduced. Finally, the presence of neuropilin-1 in some white adipocytes raises the interesting possibility that Sema3A also exerts an autocrine-paracrine role on these cells.

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The influence of carbohydrate utilisation on the growth of three strains of Tuber borchii Vittad. mycelium (1BO, 17BO and 10RA) in culture was assessed using culture media containing glucose (control), mannose or mannitol. Mannose was the best substrate for growth of the strains and this was particularly evident for strain 17BO. Mannitol instead was metabolized only by 10RA and 1BO. In order to explain the different growth trends, analyses of enzyme levels, kinetic parameters, protein patterns and the morphology of the three strains were carried out. Our results show that these strains of T. borchii mycelium were affected by the substrates used in the media. The aim of the present work was to optimise the in vitro production of T. borchii mycelium for use in experiments which require the fungus in precise and reproducible conditions, such as mycorrhizal synthesis or protein and nucleic acid extractions.