SUMMARYPhosphorus-31 nuclear magnetic resonance spectroscopy was used to estimate the levels of polyphosphates and to probe their intracellular environment in the ectomycorrhizal fungi Cenococcum graniforme Ferd. & Wing, and Heheloma crustuUniforme (Bull.) Quel. Polyphosphate content was a function of the growth phase and nitrogen content in the medium, lowest in rapidly growing mycelia, highest in older and N-starved cultures. During phosphorus depletion the polyphosphate store was mobilized; degradation of the polymer was rapid in H. crustuUniforme, whereas it was slower in C. graniforme. This difference between the two fungi might be related to differences in the intracellular physical state of polyphosphates.Measurements of nuclear magnetic relaxation parameters, such as resonance line widths and spin-lattice relaxation times, Ty, have been carried out in model systems and in intact mycelia with the aim of characterizing the physical state of polyphosphates. The intracellular Tj of inner P of polyphosphates was dramatically shorter than that in the culture medium. Polyphosphate relaxation may result from a combination of partial immobilization of the polymer by cellular components and interaction with paramagnetic ions.On the basis of these data, it is suggested that polyphosphates exist in ectomycorrhizal fungi as aggregates with reduced correlation time. A more fluid state of polyphosphates in H. crustuUniforme than in C. graniforme might allow their rapid degradation by polyphosphatases.

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ABSTRACINatural-abundance '3C nuclear magnetic resonance spectoscopy has been used to study intact mycelia of the ectomycorrhizal fungi Cenococ-cur gmniforme (Ascomycetes) and Hebeloma crastliniforme (Basidiomycetes These results suggest that fatty acids droplets could be involved in carbon storage and metabolism from ectomycorrhizal fungi.Ectomycorrhizal fungi live in symbiotic association with the roots of the major part of woody species. The mycobiont stimulates greatly the phosphorus and nitrogen uptake and assimilation ofthe plant (5). The processes occurring in the fungal partner require a continuous supply of reduced carbon and energy sources for biosynthetic reactions. In ectomycorrhizas and ericoid mycorrhizas, it has been shown that the host-plant photosynthates are translocated to the fungus and used to form specific fungal carbohydrates and polyols, such as trehalose and mannitol (7,13). However, the pathway of carbon utilization is still uncertain and, so far, relatively few studies have been directed towards the understanding of the identity and structural organization of carbon stored compounds (5, 9) in ectomycorrhizas and ectomycorrhizal fungi.In the course of a project concerning the application of NMR2 spectroscopy to the study of ectomycorrhizal fungi metabolism in vivo (8)

A method using proton FT NMR and double irradiation has been used in order to obtain 1H– 15N and 1H– 13C direct couplings of unlabelled s-triazine in the nematic phase. These couplings allow a complete structural determination. Large distortions of the aromatic ring with respect to hexagonal geometry are observed.

An indirect method is employed for determining the 15N parameters at the natural abundance level in a series of simple acyclic and cyclic amides. The one bond coupling constant, 'J(l5N1H), and the 15N chemical shift are measured as a function of the carbonyl substituent group or the ring sue and the nature of the solvent (CCI, or &O). These 15N parameters are related to the amide bond structure, the nitrogen configuration and possible intermolecular hydrogen bonding (amide-amide or amide-water).