Carbohydrate and amino acid metabolism in Tuber borchii mycelium during glucose utilization: a (13)C NMR study.

Istituto di Chimica Biologica "Giorgio Fornaini," Università degli Studi di Urbino, Via A Saffi, 2, 61029 (PU), Urbino, Italy.
Fungal Genetics and Biology (Impact Factor: 3.26). 08/2003; 39(2):168-75. DOI: 10.1016/S1087-1845(03)00006-9
Source: PubMed

ABSTRACT The metabolism of [1-13C]glucose in the vegetative mycelium of the ectomycorrhizal ascomycete Tuber borchii was studied in order to characterize the biochemical pathways for the assimilation of glucose and amino acid biosynthesis. The pathways were characterized using nuclear magnetic resonance spectroscopy in conjunction with [1-13C]glucose labeling. The enzymes of mannitol cycle and ammonium assimilation were also evaluated. The majority of the 13C label was incorporated into mannitol and this polyol was formed via a direct route from absorbed glucose. Amino acid biosynthesis was also an important sink of assimilated carbon and 13C was mainly incorporated into alanine and glutamate. From this intramolecular 13C enrichment, it is concluded that pyruvate, arising from [1-13C]glucose catabolism, was used by alanine aminotransferase, pyruvate dehydrogenase and pyruvate carboxylase before entering the Krebs cycle. The transfer of 13C-labeled mycelium on [12C]glucose showed that mannitol, alanine, and glutamate carbon were used to synthesize glutamine and arginine that likely play a storage role.

  • Source
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this study, the physiological functions of fungal mannitol metabolism in the pathogenicity and protection against environmental stresses were investigated in the necrotrophic fungus Alternaria brassicicola. Mannitol metabolism was examined during infection of Brassica oleracea leaves by sequential HPLC quantification of the major soluble carbohydrates and expression analysis of genes encoding two proteins of mannitol metabolism, i.e., a mannitol dehydrogenase (AbMdh), and a mannitol-1-phosphate dehydrogenase (AbMpd). Knockout mutants deficient for AbMdh or AbMpd and a double mutant lacking both enzyme activities were constructed. Their capacity to cope with various oxidative and drought stresses and their pathogenic behavior were evaluated. Metabolic and gene expression profiling indicated an increase in mannitol production during plant infection. Depending on the mutants, distinct pathogenic processes, such as leaf and silique colonization, sporulation, survival on seeds, were impaired by comparison to the wild-type. This pathogenic alteration could be partly explained by the differential susceptibilities of mutants to oxidative and drought stresses. These results highlight the importance of mannitol metabolism with respect to the ability of A. brassicicola to efficiently accomplish key steps of its pathogenic life cycle.
    Frontiers in Plant Science 01/2013; 4:131. · 3.60 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This analysis aims to provide an update in the recent truffle research through the chosen articles published in scientific journals. The journals were chosen based upon journal profiles and scientific prestige. Authors have considered publications from: Applied and Environmental Microbiology, Biochemical Journal, BMC Bioinformatics, BMC Genomics, Current Genetics, Environmental Microbiology, Eukaryotic Cell, FEMS Microbiology Ecology, Food Chemistry, Fungal Diversity, Fungal Genetics and Biology, Journal of Agricultural and Food Chemistry, Mycological Research (Fungal Biology), Mycorrhiza and New Phytologist. The number of analysed 124 articles shows the results over the twenty years period (1993-2012). Critical analysis has been used to determine thematic scope, whilst bibliometric study identifies development directions.
    Scientific research and essays 10/2013; 8(38):1837-1847. · 0.32 Impact Factor


Available from
Jun 3, 2014