Thomas W Baumann | University of Zurich, Switzerland (original) (raw)
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Papers by Thomas W Baumann
Acta Amazonica, Jun 1, 1980
Plant Cell Reports, 1992
A novel type of somatic embryogenesis characterized by an efficient and highly synchronized embry... more A novel type of somatic embryogenesis characterized by an efficient and highly synchronized embryo formation was observed in embryogenic callus of Coffea arabica initiated on Murashige and Skoog medium containing kinetin (4 mg/1) and 2,4-D (1 rag/l). It occurs in suspension and goes along with the suppression of "High Frequency Somatic Embryo Induction" (HFSE). This is achieved by favoring during cultivation senescence-or necrosis-like processes which apparently do not impair the competence for embryogenesis. Since the resulting embryos germinate at a rate of 94.5 % without the need of a maturation step, we propose the term "Self-Controlled Somatic Embryogenesis" (SCSE). In addition, HFSE was optimized using half-strength liquid medium with 0.1 mg/1 kinetin and 0.25 mg/l 2,4-D for proliferation of embryonic tissue, and 2.6 rag/1 ABA for maturation of embryos. Yields as well as germination rates of HFSE embryos were markedly lower as compared to SCSE.
Journal of Experimental Botany, 1994
Abstract Ripe coffee seeds (Coffea arabica L.) contain large quantities of the purine alkaloid ca... more Abstract Ripe coffee seeds (Coffea arabica L.) contain large quantities of the purine alkaloid caffeine and the depside chlorogenic acid (5-O-caffeoyl-quinic acid). Directly after germination, both compounds were recovered almost exclusively in the cotyledons and ...
Planta Medica, Aug 1, 1991
The achenes (fruits) of the therapeutically used Echinacea species E. purpurea, E. angustifolia, ... more The achenes (fruits) of the therapeutically used Echinacea species E. purpurea, E. angustifolia, and E. pallida can be differentiated structurally (shape, anatomy) as well as phytochemically (essential oil components, alkamides). During germination in all three species dodeca-2E, 4E, 8Z, 10E(10Z)-tetraenoic acid isobutylamide (8/9) is mainly formed. Besides this a number of alkamides typical for the root of E. purpurea are synthesized in moderate amounts. Also, alkene derivatives of isovalerianic acid are produced. It is an interesting fact that neither 2-monoene alkalmides nor polyacetylenes could be detected during achene germination.
Phytochemistry, 1987
ABSTRACT
Plant Journal, May 1, 1994
Shortly after germination, alkaloids are rapidly synthesized in seedlings of both Catharanthus ro... more Shortly after germination, alkaloids are rapidly synthesized in seedlings of both Catharanthus roseus L.G. Don and Cinchona ledgeriana Moens. The effect of low-level, atmospheric methyl jasmonate on this developmentally controlled process was studied. In both species, about 1 p.p.m. of methyl jasmonate vapor significantly enhanced alkaloid synthesis during germination, resulting in a doubling of alkaloid content in seedlings. Treatment with methyl jasmonate resulted in increased allocation of alkaloid precursors and in enhanced enzyme activities in alkaloid biosynthesis. The ability of methyl jasmonate to increase alkaloid biosynthesis decreased with age of the seedlings. Susceptibility of the process to methyl jasmonate was confined to a narrow time interval where the developmentally regulated onset of alkaloid synthesis occurred. When methyl jasmonate was applied at later developmental stages, its ability to enhance alkaloid content in the seedlings declined sharply.
Plant Cell Tissue and Organ Culture, 1995
The number of dividing microspores of Coffea arabica L. cv. Catuai and Catimor could be drastical... more The number of dividing microspores of Coffea arabica L. cv. Catuai and Catimor could be drastically increased in microspore media containing 16% (w/v) coconut milk, allowing cell divisions to continue in the microspore and multicellular microspores to survive until day 60. After a cold treatment, the microspores were mechanically isolated prior to cultivation in Murashige and Skoog medium supplemented with sucrose and maltose and (mg 1-l) 2,4-D: 2, BAP: I or a combination of kinetin: .5, 2,4-9:.5 and NAA: .5 as stationary suspension at a density of 1,200/ml. The crucial stage during microsporogenesis suitable for in vitro androgenesis proved to be mid uninucleate till early binucleate in flowerbuds with the size of 13-15 mm two to three days before anthesis. The initial steps of androgenesis were determined.
International Symposium on Natural Phenols in Plant Resistance, 1994
Phytochemistry, Oct 1, 2003
Among the few purine alkaloid-containing genera consumed as stimulants, Paullinia is the least in... more Among the few purine alkaloid-containing genera consumed as stimulants, Paullinia is the least investigated with respect to both chemotaxonomy and within-the-plant allocation of caffeine and its allies. Since purine alkaloids (PuA) have been proved to be valuable marker compounds in chemotaxonomy, 34 species of Paullinia and related genera were screened for them, but only one, P. pachycarpa, was positive in addition to the already known P. cupana and P. yoco. The PuA allocation in P. pachycarpa was examined and found to be restricted to theobromine in the stem, leaves and flowers. Moreover, the theobromine concentration in the stem cortex increased significantly towards the base of the plant. Since the stem cortex of P. yoco is traditionally used by the natives of Colombia and Ecuador to prepare a caffeine-rich beverage, we suspected that within the genus Paullinia the PuA are preferentially allocated to the older parts of the stem and not to young shoots like e.g., in the coffee plant (Coffea spp.). Indeed, the axis (greenhouse) of P. cupana (guarana´), known for its caffeine-rich seeds, exhibited a basipetal PuA gradient (0.005-0.145%). Moreover, the analysis of young cortex samples (herbarium) and of one piece of old stem (museum collection) revealed the same for P. yoco, even though we found much less (0.5 vs 2.5%) caffeine in the old cortex as compared to the only two analyses in 1926 of similar material. However, this discrepancy may be explained by the high variability of the PuA pattern we detected among yoco, the diversity of which the Indians take advantage.
Cookbooks, Food & Wine, Addio al Castagnaccio ?, Jun 28, 2015
Natural Product Communications
The prevailing hypothesis of caffeine biosynthesis starting from xanthosine was combined with Kre... more The prevailing hypothesis of caffeine biosynthesis starting from xanthosine was combined with Kremers’ speculation on NAD as a biochemical precursor of caffeine and trigonelline in coffee. This bold sketch together with a few free-spirited ideas may channel future caffeine biosynthesis studies into novel directions.
Biochemie und Physiologie der Pflanzen
Acta Amazonica, Jun 1, 1980
Plant Cell Reports, 1992
A novel type of somatic embryogenesis characterized by an efficient and highly synchronized embry... more A novel type of somatic embryogenesis characterized by an efficient and highly synchronized embryo formation was observed in embryogenic callus of Coffea arabica initiated on Murashige and Skoog medium containing kinetin (4 mg/1) and 2,4-D (1 rag/l). It occurs in suspension and goes along with the suppression of "High Frequency Somatic Embryo Induction" (HFSE). This is achieved by favoring during cultivation senescence-or necrosis-like processes which apparently do not impair the competence for embryogenesis. Since the resulting embryos germinate at a rate of 94.5 % without the need of a maturation step, we propose the term "Self-Controlled Somatic Embryogenesis" (SCSE). In addition, HFSE was optimized using half-strength liquid medium with 0.1 mg/1 kinetin and 0.25 mg/l 2,4-D for proliferation of embryonic tissue, and 2.6 rag/1 ABA for maturation of embryos. Yields as well as germination rates of HFSE embryos were markedly lower as compared to SCSE.
Journal of Experimental Botany, 1994
Abstract Ripe coffee seeds (Coffea arabica L.) contain large quantities of the purine alkaloid ca... more Abstract Ripe coffee seeds (Coffea arabica L.) contain large quantities of the purine alkaloid caffeine and the depside chlorogenic acid (5-O-caffeoyl-quinic acid). Directly after germination, both compounds were recovered almost exclusively in the cotyledons and ...
Planta Medica, Aug 1, 1991
The achenes (fruits) of the therapeutically used Echinacea species E. purpurea, E. angustifolia, ... more The achenes (fruits) of the therapeutically used Echinacea species E. purpurea, E. angustifolia, and E. pallida can be differentiated structurally (shape, anatomy) as well as phytochemically (essential oil components, alkamides). During germination in all three species dodeca-2E, 4E, 8Z, 10E(10Z)-tetraenoic acid isobutylamide (8/9) is mainly formed. Besides this a number of alkamides typical for the root of E. purpurea are synthesized in moderate amounts. Also, alkene derivatives of isovalerianic acid are produced. It is an interesting fact that neither 2-monoene alkalmides nor polyacetylenes could be detected during achene germination.
Phytochemistry, 1987
ABSTRACT
Plant Journal, May 1, 1994
Shortly after germination, alkaloids are rapidly synthesized in seedlings of both Catharanthus ro... more Shortly after germination, alkaloids are rapidly synthesized in seedlings of both Catharanthus roseus L.G. Don and Cinchona ledgeriana Moens. The effect of low-level, atmospheric methyl jasmonate on this developmentally controlled process was studied. In both species, about 1 p.p.m. of methyl jasmonate vapor significantly enhanced alkaloid synthesis during germination, resulting in a doubling of alkaloid content in seedlings. Treatment with methyl jasmonate resulted in increased allocation of alkaloid precursors and in enhanced enzyme activities in alkaloid biosynthesis. The ability of methyl jasmonate to increase alkaloid biosynthesis decreased with age of the seedlings. Susceptibility of the process to methyl jasmonate was confined to a narrow time interval where the developmentally regulated onset of alkaloid synthesis occurred. When methyl jasmonate was applied at later developmental stages, its ability to enhance alkaloid content in the seedlings declined sharply.
Plant Cell Tissue and Organ Culture, 1995
The number of dividing microspores of Coffea arabica L. cv. Catuai and Catimor could be drastical... more The number of dividing microspores of Coffea arabica L. cv. Catuai and Catimor could be drastically increased in microspore media containing 16% (w/v) coconut milk, allowing cell divisions to continue in the microspore and multicellular microspores to survive until day 60. After a cold treatment, the microspores were mechanically isolated prior to cultivation in Murashige and Skoog medium supplemented with sucrose and maltose and (mg 1-l) 2,4-D: 2, BAP: I or a combination of kinetin: .5, 2,4-9:.5 and NAA: .5 as stationary suspension at a density of 1,200/ml. The crucial stage during microsporogenesis suitable for in vitro androgenesis proved to be mid uninucleate till early binucleate in flowerbuds with the size of 13-15 mm two to three days before anthesis. The initial steps of androgenesis were determined.
International Symposium on Natural Phenols in Plant Resistance, 1994
Phytochemistry, Oct 1, 2003
Among the few purine alkaloid-containing genera consumed as stimulants, Paullinia is the least in... more Among the few purine alkaloid-containing genera consumed as stimulants, Paullinia is the least investigated with respect to both chemotaxonomy and within-the-plant allocation of caffeine and its allies. Since purine alkaloids (PuA) have been proved to be valuable marker compounds in chemotaxonomy, 34 species of Paullinia and related genera were screened for them, but only one, P. pachycarpa, was positive in addition to the already known P. cupana and P. yoco. The PuA allocation in P. pachycarpa was examined and found to be restricted to theobromine in the stem, leaves and flowers. Moreover, the theobromine concentration in the stem cortex increased significantly towards the base of the plant. Since the stem cortex of P. yoco is traditionally used by the natives of Colombia and Ecuador to prepare a caffeine-rich beverage, we suspected that within the genus Paullinia the PuA are preferentially allocated to the older parts of the stem and not to young shoots like e.g., in the coffee plant (Coffea spp.). Indeed, the axis (greenhouse) of P. cupana (guarana´), known for its caffeine-rich seeds, exhibited a basipetal PuA gradient (0.005-0.145%). Moreover, the analysis of young cortex samples (herbarium) and of one piece of old stem (museum collection) revealed the same for P. yoco, even though we found much less (0.5 vs 2.5%) caffeine in the old cortex as compared to the only two analyses in 1926 of similar material. However, this discrepancy may be explained by the high variability of the PuA pattern we detected among yoco, the diversity of which the Indians take advantage.
Cookbooks, Food & Wine, Addio al Castagnaccio ?, Jun 28, 2015
Natural Product Communications
The prevailing hypothesis of caffeine biosynthesis starting from xanthosine was combined with Kre... more The prevailing hypothesis of caffeine biosynthesis starting from xanthosine was combined with Kremers’ speculation on NAD as a biochemical precursor of caffeine and trigonelline in coffee. This bold sketch together with a few free-spirited ideas may channel future caffeine biosynthesis studies into novel directions.
Biochemie und Physiologie der Pflanzen