To compare the toxic effects of a Delphinium occidentale chemotype containing N-(methylsuccinimido) anthranoyllycoctonine (MSAL)-type alkaloids and a D occidentale chemotype lacking MSAL-type alkaloids in mice and cattle.
225 male Swiss Webster mice and 11 Black Angus steers.
4 collections of larkspur containing MSAL-type alkaloids and 4 collections of larkspur lacking MSAL-type alkaloids were used. From each collection, total alkaloid extracts (0.05 to 0.20 mL) were administered via tail-vein injection in 27 to 29 mice. Dried, finely ground plant material from 1 collection with and 1 collection without MSAL-type alkaloids (doses equivalent to 37.6 mg of total alkaloids/kg) were each administered to 8 cattle via oral gavage in a crossover experiment; 3 cattle received a single dose equivalent to 150.4 mg of total alkaloids/kg (no MSAL-type alkaloids). In mice, clinical effects were monitored; in cattle, heart rate was monitored before (baseline) and 24 hours after treatment. At the 24-hour time point, cattle were exercised as a measure of muscle weakness.
In mice, mean LD(50) associated with alkaloid extracts prepared from plants that did or did not contain MSAL-type alkaloids was 2.3 and 54.2 mg/kg, respectively. In cattle at 24 hours after treatment, plant material containing MSAL-type alkaloids significantly increased heart rate from baseline and was associated with exercise-induced collapse; plant material lacking MSAL-type alkaloids had no similar effects.
Taxonomic classification of D occidentale alone was not a good indicator of the toxic risk to grazing cattle.
"provides minimal predictive value of D . stachydeum toxicity in cattle . Furthermore , D . occidentale from Logan , UT that contains only the non - MSAL - type alkaloids , when dosed at an equal dose to D . stachydeum ( 82 . 5 mg / kg ) or even dosed up to 150 . 4 mg total alkaloid / kg BW has elicited no clinical signs in previous dosing trials ( Cook et al . , 2011 ) . These data suggest that the response of cattle dosed with larkspur is not strictly due to the absence , or presence , of the MSAL - type alkaloids . Rather , it is the qualitative composition of the total alkaloids in a given species that determines how cattle may respond to a given larkspur species . Differences in toxicity between"
"However, Pozo et al.  found that yeast growth was negatively affected by the alkaloids atropine and tropine found in the nectar of Atropa baetica. Given the well-known bioactivity of norditerpene alkaloids against vertebrate and invertebrate herbivores , , testing the effects of norditerpene alkaloids on nectar microbial communities warrants further investigation. "
[Show abstract][Hide abstract] ABSTRACT: Microorganisms frequently colonize the nectar of angiosperm species. Though capable of altering a suite of traits important for pollinator attraction, few studies exist that test the degree to which they mediate pollinator foraging behavior. The objective of our study was to fill this gap by assessing the abundance and diversity of yeasts associated with the perennial larkspur Delphinium barbeyi (Ranunculaceae) and testing whether their presence affected components of pollinator foraging behavior. Yeasts frequently colonized D. barbeyi nectar, populating 54-77% of flowers examined depending on site. Though common, the yeast community was species-poor, represented by a single species, Metschnikowia reukaufii. Female-phase flowers of D. barbeyi were more likely to have higher densities of yeasts in comparison to male-phase flowers. Pollinators were likely vectors of yeasts, as virgin (unvisited) flowers rarely contained yeasts compared to flowers open to pollinator visitation, which were frequently colonized. Finally, pollinators responded positively to the presence of yeasts. Bombus foragers both visited and probed more flowers inoculated with yeasts in comparison to uninoculated controls. Taken together, our results suggest that variation in the occurrence and density of nectar-inhabiting yeasts have the potential to alter components of pollinator foraging behavior linked to pollen transfer and plant fitness.
PLoS ONE 10/2014; 9(10):e108214. DOI:10.1371/journal.pone.0108214 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cattle are poisoned by N-(methylsuccinimido) anthranoyllycoctonine type (MSAL-type) and 7,8-methylenedioxylycoctonine type (MDL-type) norditerpenoid alkaloids in Delphinium spp. Alkaloids in D. glaucescens are primarily of the MSAL-type, while D. barbeyi is a mixture of MSAL and MDL-types. The objectives of this study were to determine and compare the toxicokinetics of selected alkaloids from D. glaucescens and D. barbeyi in cattle. The two species of larkspur were dosed to three groups of Angus steers via oral gavage at doses of 8 mg kg⁻¹ MSAL-type alkaloids for D. barbeyi and either 8.0 or 17.0 mg kg⁻¹ MSAL-type alkaloids for D. glaucescens. In cattle dosed with D. barbeyi, serum deltaline (MDL-type) concentrations peaked at 488 ± 272 ng ml⁻¹ at 3 h and serum methyllycaconitine (MSAL-type) concentrations peaked at 831 ± 369 ng ml⁻¹ at 6 h. Deltaline was not detected in the serum of cattle dosed with D. glaucescens. Serum methyllycaconitine concentrations peaked at 497 ± 164 ng ml⁻¹ at 18 h, and 1089 ± 649 ng ml⁻¹ at 24 h for the 8 mg kg⁻¹ and 17 mg kg⁻¹ doses of D. glaucescens respectively. There were significant differences between the maximum serum concentrations and the area under the curve for the two doses of D. glaucescens but not D. barbeyi. Results from this experiment support the recommendation that approximately 7 days are required to clear 99% of the toxic alkaloids from the serum of animals orally dosed with D. barbeyi or D. glaucescens, and that MDL-type alkaloids play an important role in the toxicity of Delphinium spp. in cattle.
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