|Statement||Wilhelmina Hermina Geertruida Hol.|
|LC Classifications||QK898.P97 H65 2003|
|The Physical Object|
|Pagination||78 p. :|
|Number of Pages||78|
|LC Control Number||2004464067|
We examined the effects of water and nutrient availability on the expression of the defense pyrrolizidine alkaloids (PAs) in Senecio jacobaea and S. o jacobaea, and S. aquaticus are adapted to different natural habitats, characterized by differing abiotic conditions and different selection pressures from natural enemies. We tested if PA concentration and diversity are plastic Cited by: Senecio and Jacobaea, possessing pyrrolizidine alkaloids (PAs) as their characteristic defense compounds, have been chosen in several studies as model species to assess the quantitative and qualitative variation in SMs in native and introduced populations. PAs act as deterrents or toxins to non-adapted herbivores and by: 5. Pyrrolizidine alkaloids Alkaloid origin Microorganisms Inhibition concentration (mg/ml) Senecio and Jacobaea species, which are macrocyclic diesters (see Fig. 1). Hol and van Veen () important role in the defence against microorganisms in natural systems. concentration and composition of defense chemicals is important to defend themselves against the guild of herbivores in a new range. Senecio and Jacobaea, possessing pyrrolizidine alkaloids (PAs) as their characteristic defense compounds, have been chosen in several studies as model species to assess the.
pyrrolizidine alkaloids as N-oxides must be advantageous to the sequestering species. The present study was undertaken to understand the role of the N-oxide state of pyrrolizidine alkaloids in alkaloid sequester- ing insects. Particularly the mechanisms of resorption of orally ingested tertiary pyrrolizidine alkaloids or their N-oxides from. Pyrrolizidine‐alkaloid‐sequestering insects store the alkaloids as nontoxic N ‐oxides which are reduced in the guts of any potential insectivore. The lipophilic tertiary alkaloid is absorbed passively and then bioactivated by cytochrome P oxidase. Changes in the defence compounds pyrrolizidine alkaloids (PAs) in roots and shoots of Senecio jacobaea are reported in response to nutrient addition in order to investigate whether changes in concentration are adaptive.. PA concentrations were examined in leaves and roots of 40 vegetative ragwort plants, subjected to four nutrient treatments in a climate chamber study. Evolution of pyrrolizidine alkaloid biosynthesis in Apocynaceae: revisiting the defence de‐escalation hypothesis. and/or by sequestering the chemicals for use in defence against their predators (Petschenka & Agrawal, ). because populations of Senecio jacobaea.
PPRL Plants Containing Pyrrolizidine Alkaloids Compositae Senecio ( species) S. jacobaea (tansy ragwort) S. vulgaris (common groundsel) S. longilobus (threadleaf groundsel) S. riddellii (Riddell groundsel) Fabaceae (Liguminosae) Crotalaria ( species) C. sagittalis (rattlebox) C. spectabilis (showy crotalaria) C. retusa (wedge-leaf rattlebox). to 1,2-dehydropyrrolizidine alkaloids is a signiﬁcant cause of some of these costly and debilitating diseases, then this should lead to initiatives to reduce the level of these alkaloids in the food chain. Pyrrolizidine alkaloids (PAs), key anti-herbivore defence compounds in ragwort, dominated the metabolomic profiles of root and shoot extracts. Analyses of the metabolomic profiles revealed an increase in four PAs in roots (but not shoots) of AMF colonised plants, with the potential to protect colonised plants from below-ground organisms. Hol WHG () Role of pyrrolizidine alkaloids in the defense against fungi. PhD thesis, Leiden University, Leiden, The Netherlands; Hol WHG, Veen JA. Pyrrolizidine alkaloids from Senecio jacobaea affect fungal growth. J Chem Ecol. ; – doi: /A Hol WHG, Vrieling K, Veen JA.