Carbohydrate and amino acid metabolism in Tuber borchii mycelium during glucose utilization: a (13)C NMR study.
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.
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ABSTRACT: To test the hypothesis that truffle-associated bacteria may improve truffle nutrition, we isolated bacteria from white truffle ascocarps and tested Actinobacteria for their ability to solubilise phosphate and iron, nutrients that have limited availability in white truffle grounds. Two isolates with sequence similarities to Curtobacterium flaccumfaciens and Rhodococcus sp. were characterized in detail. Both solubilised Ca3(PO4)2 in a way that was dependent on the nitrogen and carbon sources present. Neither strain broke down phytate, but both produced chelating compounds, performed ammonification, and broke down β-glucan. Additionally, C. flaccumfaciens decomposed chitin, pectin, lipids and proteins, while Rhodococcus sp. exhibited urease activity. Three potentially fungicolous fungi were isolated from diseased white truffle ascocarps and bioassayed against the isolated Actinobacteria. The Rhodococcus isolate inhibited Verticillium leptobactrum, neither bacterium affected Clonostachys rosea, while both isolates promoted growth of Trichoderma sp. The results suggest that Actinobacteria might be involved in improving truffle nutrition, ascocarp degradation and establishing relationships with other soil fungi.Fungal Ecology 12/2013; 6(6):527-538. DOI:10.1016/j.funeco.2013.05.006 · 2.99 Impact Factor
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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. DOI:10.5897/SRE2013.5620 · 0.45 Impact Factor
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ABSTRACT: Available information on bacteria that influence the economically important white truffle (Tuber magnatum Pico) life cycle is scarce. From the ascocarp of white truffle we isolated a strain TMG 022C, capable for growth in nitrogendepleted conditions and assimilation of mannitol and trehalose. According to 16S rDNA sequence phylogeny, the strain was closely related to Sphingobium amiense. The strain had the ability to perform ammonification, reduce nitrate and solubilize Ca3(PO4)2, produce chitinase, lipase, phospholipase and β-glucanase, but not cellulase, pectinase, protease and siderophores. The results suggest that Sphingobium sp. TMG 022C could have an influence on the Tuber magnatum life cycle through improved mycelium nutrition and ascocarp decomposition.Archives of Biological Sciences 01/2011; 63(3):697-704. DOI:10.2298/ABS1103697P · 0.61 Impact Factor