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In vivo 15N NMR spectra of 15N-labelled Datura stramonium and Nicotiana tabacum transformed root cultures have been obtained. It is shown for the first time that nitrogenous secondary metabolites can be detected using in vivo 15N NMR, and that information can be deduced on the subcellular distribution of nicotine.

The relationship between shoot growth and rooting was examined in two, 'difficult-to root' amenity trees, Syringa vulgaris L. cv. Charles Joly and Corylus avellana L. cv. Aurea. A range of treatments reflecting severity of pruning was imposed on field-grown stock prior to bud break. To minimise variation due to the numbers of buds that developed under different treatments, bud number was restricted to 30 per plant. Leafy cuttings were harvested at different stages of the active growth phase of each species. With Syringa, rooting decreased with later harvests, but loss of rooting potential was delayed in cuttings collected from the most severe pruning treatment. Rooting potential was associated with the extent of post-excision shoot growth on the cutting but regression analyses indicated that this relationship could not entirely explain the loss of rooting with time, nor the effects due to pruning. Similarly, in Corylus rooting was promoted by severe pruning, but the relationship between apical growth on the cutting and rooting was weaker than in Syringa, and only at the last harvest did growth play a critical role in determining rooting. Another unusual factor of the last harvest of Corylus was a bimodal distribution of roots per cutting, with very few rooted cuttings having less than five roots. This implies that, for this harvest at least, the potential of an individual cutting to root is probably not limited by the number of potential rooting sites.

The biosynthesis of the opine agropine in transformed Nicotiana tabacum L. root cultures was studied using in vivo 15 N nuclear magnetic resonance (NMR) spectroscopy. Roots were incubated with [ 15 N]ammonium and/or [ 15 N]nitrate, and the incorporation of the label into agropine, conjugated polyamines, γ-aminobutyric acid (GABA), glutamate (Glu), glutamine (Gln) and nicotine was monitored by NMR. The largest labelled pool was agropine in cells grown on a 15 N-enriched medium and its synthesis was maintained, to the detriment of the Gln pool, under conditions of nitrogen (N) starvation. These observations indicate that the synthesis of agropine is not tightly regulated and that it represents a significant sink for carbon (C) and N in the plant. The addition of α-naphthaleneacetic acid (NAA) and kinetin to the growth medium caused de-differentiation of the root cultures and perturbation of secondary N metabolism. The amount of agropine relative to Gln increased but the total accumulation of agropine decreased, in part because of the increase in the synthesis of conjugated polyamines. These results show that agropine biosynthesis perturbs both primary and secondary N metabolism, and that the perturbation differs according to the culture conditions and the imposed stress.

J. Am. Soc. Brew. Chem. 72(1):12-21, 2014 Gushing is the vigorous overfoaming of carbonated beverages when the bottle is opened. Primary gushing in beer is mostly caused by a group of proteins called hydrophobins secreted by filamentous fungi, which contaminate CO2 gaseous molecules during carbonation and form nanobubbles. The influence of hop oil antifoam on primary gushing showed a complete suppressing effect in sparkling water, a decreasing effect in wort, and no influence on gushing-positive beers. This shows the importance of the critical point of addition of this product in the brewing process. GC and GC-MS analysis show that commercial available lipophilic hop extract comprises fatty acids, either saturated fatty acids (SFA) or unsaturated fatty acids (UFA) (both free and incorporated in mono-, di-, and triglycerides), waxes (long-chain alkanes), and steroid compounds. Gushing analysis of each compound showed that SFA and UFA behave in a different manner regarding gushing. In contrast to SFA and trans-form UFA, cis-form UFAs do not induce gushing. Long-chain alkanes provide sufficient hydrophobic structures to interact with gaseous CO2 molecules and induce gushing. Because hop antifoam molecules are hydrophobic, they interact with hydrophobins and prevent interaction with CO2 and, consequently, inhibit the possibilities of development of the explosive nanobubble structure.

In vivo 15N NMR spectroscopy has been used to study the metabolism of [15N]tropinone in transformed root cultures of Datura stramonium. It was shown that, within only 2–4 hr of application of the labelled precursor, labelled metabolites can readily be detected. It was further demonstrated that de-differentiated cultures, derived from the roots by treatment with phytohormones, are capable of metabolising [15N]tropinone to [15N]tropine and simple [15N]tropine esters but that these cultures cannot convert [15N]tropinone to [15N]hyoscyamine.