We have previously shown that pooled low molecular weight compounds (LMWCs) isolated from culture... more We have previously shown that pooled low molecular weight compounds (LMWCs) isolated from culture filtrates of both forms of the barley net blotch pathogenPyrenophora terescause chlorosis. In this study, the LMWCs were further characterised and individually identified. The LMWCs were non-host selective compounds and their activityin planta was temperature and light-dependent suggesting a role in tar-geting metabolism and light-dependent organelles such as the chloroplast. Although the previously characterised toxinsN-(2-amino-2-carboxyethyl) aspartic acid (Toxin A), 1-(2-amino-2-carboxyethyl)-6-carboxy-3-carboxymethyl-2-piperazinone (Toxin B), andN-[2-(2-amino-2-carboxy ethyl-amino)-2-car-boxyethyl] aspartic acid (Toxin C) were identified, a number of other chlorosis-causing compounds were also isolated. Here, we report the first isolation of aspergillomarasmine B fromP. teresmedia filtrates as well as the isolation and description of a unique u.v.-absorbing phytotoxic LMWC which ap...
Pyrenophora teres, the causal agent of net blotch of barley (Hordeum vulgare L.), induces distinc... more Pyrenophora teres, the causal agent of net blotch of barley (Hordeum vulgare L.), induces distinctive long dark brown lesions (the net form) or dark brown spots (the spot form), both with surrounding chlorosis. Proteins isolated from P. teres f. teres (the net form) and P. teres f. maculata (the spot form) induce host-specific necrosis. In this study, the activity of
We have previously shown that pooled low molecular weight compounds (LMWCs) isolated from culture... more We have previously shown that pooled low molecular weight compounds (LMWCs) isolated from culture filtrates of both forms of the barley net blotch pathogen Pyrenophora teres cause chlorosis. In this study, the LMWCs were further characterised and individually identified. The LMWCs were non-host selective compounds and their activity in planta was temperature and light-dependent suggesting a role in targeting metabolism
ABSTRACT Pyrenophora teres, the causal agent of net blotch of barley (Hordeum vulgare L.), induce... more ABSTRACT Pyrenophora teres, the causal agent of net blotch of barley (Hordeum vulgare L.), induces a combination of necrosis and extensive chlorosis in susceptible barley cultivars. Cell-free filtrates from both net and spot forms of P. teres; P. teres f. sp. teres, and P. teres f. sp. maculata were found to contain phytotoxic low molecular weight compounds (LMWCs) and proteinaceous metabolites which appear to be responsible for different components of the symptoms induced by the two forms of the pathogen in a susceptible cultivar of barley (cv. Sloop). Proteins induced only brown necrotic spots or lesions similar to those induced by the pathogens 72 h after inoculation. In contrast, LMWCs induced general chlorosis seen 240 h after inoculation but not the localized necrosis. Neither hydrolyzed or heat- or protease-treated proteinaceous metabolites induced the symptoms. This is the first report of the involvement of proteins produced by P. teres in symptom development during net blotch disease of barley.
NH2OH, the first intermediate in the oxidation of NH4+ to nitrite by the nitrifying bacterium, Ni... more NH2OH, the first intermediate in the oxidation of NH4+ to nitrite by the nitrifying bacterium, Nitrosomonas europaea, was recovered as the oxime of cyclohexanone. 15N, 18O-tracer experiments using highly enriched 15NH4Cl and 18O2 yielded oxime that was correspondingly highly enriched (greater than or equal to 92 atom %) in these isotopes. These results show that the source of NH2OH is largely or entirely NH4+, as opposed to hydrazine, which was added to inhibit the further oxidation of NH2OH to nitrite, and that NH4+ yields NH2OH by way of a monooxygenase reaction involving direct insertion of O from O2. The oxidation of NH4+ and NH2OH must be functionally linked in N. europaea, inasmuch as the reducing equivalents required by the monooxygenase to reduce the second atom of O2 to water can arise only through the concomitant oxidation of NH2OH.
... of O-phosphoryl-ethanolamine may depend upon age, dietary factors, or circadian rhythms (Lena... more ... of O-phosphoryl-ethanolamine may depend upon age, dietary factors, or circadian rhythms (Lenartowicz and Niemerko, '64; Licata et al ... us to consider the intriguing possibility that, as in the case of the hereditary bone disease Hypophosphatasia (Fraser and Lucas, '57), there ...
... Ltd GLUCOSIDES OF ETHYL INDOLE-3-LACTATE AND UROTERPENOL IN RIESLING WINE VASSILIOS A MAKINGS... more ... Ltd GLUCOSIDES OF ETHYL INDOLE-3-LACTATE AND UROTERPENOL IN RIESLING WINE VASSILIOS A MAKINGS, MAX E TATE and PATRICK J WILLIAMS* Department of Plant Science, Waite Agricultural Research Institute, The University of Adelaide, Glen Osmond, SA ...
We have previously shown that pooled low molecular weight compounds (LMWCs) isolated from culture... more We have previously shown that pooled low molecular weight compounds (LMWCs) isolated from culture filtrates of both forms of the barley net blotch pathogenPyrenophora terescause chlorosis. In this study, the LMWCs were further characterised and individually identified. The LMWCs were non-host selective compounds and their activityin planta was temperature and light-dependent suggesting a role in tar-geting metabolism and light-dependent organelles such as the chloroplast. Although the previously characterised toxinsN-(2-amino-2-carboxyethyl) aspartic acid (Toxin A), 1-(2-amino-2-carboxyethyl)-6-carboxy-3-carboxymethyl-2-piperazinone (Toxin B), andN-[2-(2-amino-2-carboxy ethyl-amino)-2-car-boxyethyl] aspartic acid (Toxin C) were identified, a number of other chlorosis-causing compounds were also isolated. Here, we report the first isolation of aspergillomarasmine B fromP. teresmedia filtrates as well as the isolation and description of a unique u.v.-absorbing phytotoxic LMWC which ap...
Pyrenophora teres, the causal agent of net blotch of barley (Hordeum vulgare L.), induces distinc... more Pyrenophora teres, the causal agent of net blotch of barley (Hordeum vulgare L.), induces distinctive long dark brown lesions (the net form) or dark brown spots (the spot form), both with surrounding chlorosis. Proteins isolated from P. teres f. teres (the net form) and P. teres f. maculata (the spot form) induce host-specific necrosis. In this study, the activity of
We have previously shown that pooled low molecular weight compounds (LMWCs) isolated from culture... more We have previously shown that pooled low molecular weight compounds (LMWCs) isolated from culture filtrates of both forms of the barley net blotch pathogen Pyrenophora teres cause chlorosis. In this study, the LMWCs were further characterised and individually identified. The LMWCs were non-host selective compounds and their activity in planta was temperature and light-dependent suggesting a role in targeting metabolism
ABSTRACT Pyrenophora teres, the causal agent of net blotch of barley (Hordeum vulgare L.), induce... more ABSTRACT Pyrenophora teres, the causal agent of net blotch of barley (Hordeum vulgare L.), induces a combination of necrosis and extensive chlorosis in susceptible barley cultivars. Cell-free filtrates from both net and spot forms of P. teres; P. teres f. sp. teres, and P. teres f. sp. maculata were found to contain phytotoxic low molecular weight compounds (LMWCs) and proteinaceous metabolites which appear to be responsible for different components of the symptoms induced by the two forms of the pathogen in a susceptible cultivar of barley (cv. Sloop). Proteins induced only brown necrotic spots or lesions similar to those induced by the pathogens 72 h after inoculation. In contrast, LMWCs induced general chlorosis seen 240 h after inoculation but not the localized necrosis. Neither hydrolyzed or heat- or protease-treated proteinaceous metabolites induced the symptoms. This is the first report of the involvement of proteins produced by P. teres in symptom development during net blotch disease of barley.
NH2OH, the first intermediate in the oxidation of NH4+ to nitrite by the nitrifying bacterium, Ni... more NH2OH, the first intermediate in the oxidation of NH4+ to nitrite by the nitrifying bacterium, Nitrosomonas europaea, was recovered as the oxime of cyclohexanone. 15N, 18O-tracer experiments using highly enriched 15NH4Cl and 18O2 yielded oxime that was correspondingly highly enriched (greater than or equal to 92 atom %) in these isotopes. These results show that the source of NH2OH is largely or entirely NH4+, as opposed to hydrazine, which was added to inhibit the further oxidation of NH2OH to nitrite, and that NH4+ yields NH2OH by way of a monooxygenase reaction involving direct insertion of O from O2. The oxidation of NH4+ and NH2OH must be functionally linked in N. europaea, inasmuch as the reducing equivalents required by the monooxygenase to reduce the second atom of O2 to water can arise only through the concomitant oxidation of NH2OH.
... of O-phosphoryl-ethanolamine may depend upon age, dietary factors, or circadian rhythms (Lena... more ... of O-phosphoryl-ethanolamine may depend upon age, dietary factors, or circadian rhythms (Lenartowicz and Niemerko, '64; Licata et al ... us to consider the intriguing possibility that, as in the case of the hereditary bone disease Hypophosphatasia (Fraser and Lucas, '57), there ...
... Ltd GLUCOSIDES OF ETHYL INDOLE-3-LACTATE AND UROTERPENOL IN RIESLING WINE VASSILIOS A MAKINGS... more ... Ltd GLUCOSIDES OF ETHYL INDOLE-3-LACTATE AND UROTERPENOL IN RIESLING WINE VASSILIOS A MAKINGS, MAX E TATE and PATRICK J WILLIAMS* Department of Plant Science, Waite Agricultural Research Institute, The University of Adelaide, Glen Osmond, SA ...
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