Location: Poisonous Plant Research2011 Annual Report
1a. Objectives (from AD-416)
Objective I: Pine Needles 1.1 Determine if isocupressic acid (ICA; the abortifacient compound in pine needles) concentration in pine needles is modulated by the environment. 1.2 Identify the matabolites of isocupressic acid in pine needles that cause abortions in cattle. Determine the biological mechanism, develop diagnostic techniques, and therapeutic procedures. 1.3 Determine factors that influence cattle consumption of pine needles and develop management practices to prevent abortion. Objective II: Broom Snakeweed 2.1 Identify the toxic and abortifacient compounds in broom snakeweed. 2.2 Describe the ecology of broom snakeweed, develop management and control guidelines to reduce incidence of poisoning and abortion in livestock. Objective III: Lupine 3.1 Isolate, identify, and evaluate toxicity and teratogenicity of lupine alkaloids which cause birth defects in calves born to cows that graze these plants. 3.2 Evaluate the role of genotype and environment on lupine alkaloids, and thus the relative toxicity of various species and populations of lupine. 3.3 Determine the physiological mechanism of lupine-induced birth defects and evaluate the maternal and fetal toxicokinetics of alkaloids. 3.4 Evaluate the influence of climate on population cycles of lupine. 3.5 Determine the importance of lupines as nutritional components for cattle during critical times of the year. 3.6 Identify conditions under which cattle graze various lupine species. Objective IV: Veratrum 4.1 Develop models to study the toxicokinetics, including clearance times, and toxicity of steroidal alkaloids in Veratrum californicum.
1b. Approach (from AD-416)
1.1 Data on environmental conditions will be collected at each site using local weather stations. ICA levels and environmental conditions will be correlated to determine if any patterns emerge. Soil samples will be collected at each site for future evaluation. 1.2 Samples of maternal and fetal tissues will be collected for histologic analysis and determination of ICA concentrations using existing ELISA’s and GC/MS methods. Proteomic analyses via LC/MS/MS techniques will be done. 1.3 Pen and field studies using cattle in high, medium and low body condition will be done to determine effects on needle consumption and grazing times. Nutrient supplements will be offered to determine if pine needle consumption will be altered. 2.1 The diterpene acid “fingerprint” of broom snakeweed from various populations in Arizona, New Mexico and Utah will be determined by chemical analysis. Subsequent in vitro and in vivo studies will be done to determine abortifacient activity. 2.2 A grazing study will be conducted to determine if various management practices can be implemented to force cattle to graze snakeweed as a biological control. A clipping study will be conducted to further describe the effects of defoliation on snakeweed and the surrounding plant community. 3.1 Alkaloids will be isolated by chemical methods and identified by chromatography, NMR, mass spectrometry, and elemental analysis. Toxicology will be evaluated using a mouse bioassay and cell lines that express nicotinic acetylcholine receptors. 3.2 A chemical fingerprint of Lupinus sulphureus collected from different locations will be generated using chemical methods. Fingerprints will be analyzed via cluster analysis and phylogenetic analysis will be performed using AFLPs (Amplified Fragment Length Polymorphisms) to determine the genetic relationship of the populations. 3.3 Pregnant goats in late gestation will be used to determine the rate of absorption, distribution and elimination of the teratogenic alkaloids. The pharmacokinetic profiles of the alkaloids will be compared between maternal and fetal systems. 3.4 Established transects will be monitored over the next 5 years to determine the influence of weather patterns on lupine density. Correlations of lupine age, class, density, and trends will be made with seasonal precipitation and temperature. 3.5 Consumption of lupines by cattle on rangelands dominated by low quality forages may be related to nutrient content. Twelve yearling heifers in a field study will be supplemented with different levels of protein to compare lupine ingestion. 3.6 Short-duration and high intensity grazing studies in early, mid, and late summer will be used to determine what role grazing pressure has on lupine intake during different seasons of the year. 4.1 A monogastric model (swine) will be used to determine the kinetics (clearance and metabolism) of a well known teratogenic alkaloid from Veratrum. This pilot project will be a model for testing the clearance of other plant toxins from animal tissues to evaluate food safety of animal products. Clearance rates between the monogastric model and small ruminant model will be compared.
3. Progress Report
In collaboration with FRRL, Logan, UT., replicated seeding plots were established in 2010 in Eastern Washington using various grass species (including improved and native germplasm) and 3 species of forage Kochia. Additionally, larger demonstration plots were seeded with a mix of crested wheat grass and Emigrant forage Kochia. The hypothesis is that crested wheat grass and forage Kochia will provide alternative forages at the critical time when pregnant cattle begin to eat lupine (July-September). Seeding plots were established on four different ranches on the Scablands and early evaluation demonstrated good to excellent germination on all plots. Further evaluations will occur over the next 5 years, and grazing studies will be done on the larger demonstration plots once the grasses and Kochia become established. The plots will be evaluated in the fall of 2011 and then each spring for the next 5 years. Chemical analysis of needles and bark from various types of pine and juniper trees continues in order to fully understand the abortion risks when late term cattle graze in areas where these types of trees are abundant. Cell culture-based experiments are being used to compare piperidine and quinolizidine alkaloids to help identify the mechanism by which these compounds induce birth defects in livestock species. Current structure-function studies are underway using compounds selective for specific receptor binding sites on the fetal muscle-type receptors comparing alkaloids which do not cause fetal malformations versus alkaloids that do. Initial results suggest that there are differences between the two classes of alkaloids, which could help to determine the molecular mechanism of teratogenesis. These results have led to the generation of the hypothesis that the mechanism behind these types of birth defects is the inhibition of fetal movement due to stimulation followed by desensitization of the receptors. A preliminary chemical analysis of leaves and seeds from Mimosa tenuiflora was performed. An initial evaluation of the teratogenic potential of leaves and seeds, as well as extracts of both, has been made using a rat model in order to identify the teratogenic compound in Mimosa tenuiflora.
Faeth, S.H., Hayes, C.J., Gardner, D.R. 2010. Asexual endophytes in a native grass: Tradeoffs in mortality, growth, reproduction, and alkaloid production. Microbial Ecology. 60:496-504. DOI: 10.1007/s00248-010-9643-4.