Poisonous Plant Research Laboratory

Many ecosystems around the world are rapidly deteriorating due to both local and global pressures, and perhaps none so precipitously as coral reefs. Management of coral reefs through maintenance (e.g., marine-protected areas, catchment management to improve water quality), restoration, as well as global and national governmental agreements to reduce greenhouse gas emissions (e.g., the 2015 Paris Agreement) is critical for the persistence of coral reefs. Despite these initiatives, the health and abundance of corals reefs are rapidly declining and other solutions will soon be required. We have recently discussed options for using assisted evolution (i.e., selective breeding, assisted gene flow, conditioning or epigenetic programming, and the manipulation of the coral microbiome) as a means to enhance environmental stress tolerance of corals and the success of coral reef restoration efforts. The 2014-2016 global coral bleaching event has sharpened the focus on such interventionist approaches. We highlight the necessity for consideration of alternative (e.g., hybrid) ecosystem states, discuss traits of resilient corals and coral reef ecosystems, and propose a decision tree for incorporating assisted evolution into restoration initiatives to enhance climate resilience of coral reefs.

More than 350 PAs have been identified in over 6,000 plants in the Boraginaceae, Compositae, and Leguminosae families (Table 1). About half of the identified PAs are toxic and several have been shown to be carcinogenic in rodents. PA-containing plants have worldwide distribution, and they probably are the most common poisonous plants affecting livestock, wildlife, and humans. In many locations, PA-containing plants are introduced species that are considered invasive, noxious weeds. Both native and introduced PA-containing plants often infest open ranges and fields, replacing nutritious plants. Many are not palatable and livestock avoid eating them if other forages are available. However, as they invade fields or crops, plant parts or seeds can contaminate prepared feeds and grains which are then readily eaten by many animals. Human poisonings most often are a result of food contamination or when PA-containing plants areused for medicinal purposes. This is a review of current information on the diagnosis, pathogenesis, and molecular mechanisms of PA toxicity. Additional discussion includes current and future research objectives with an emphasis on the development of better diagnostics, pyrrole kinetics, and the effects of low dose PA exposure.

Aberrant Hedgehog (Hh) pathway activation has been implicated in cancers of diverse tissues and organs, and the tumor growth-inhibiting effects of pathway antagonists in animal models have stimulated efforts to develop pathway antagonists for human therapeutic purposes. These efforts have focused largely on cyclopamine derivatives or other compounds that mimic cyclopamine action in binding to and antagonizing Smoothened, a membrane transductory component. We report here that arsenicals, in contrast, antagonize the Hh pathway by targeting Gli transcriptional effectors; in the short term, arsenic blocks Hh-induced ciliary accumulation of Gli2, the primary activator of Hh-dependent transcription, and with prolonged incubation arsenic reduces steady-state levels of Gli2. Arsenicals active in Hh pathway antagonism include arsenic trioxide (ATO), a curative agent in clinical use for acute promyelocytic leukemia (APL); in our studies, ATO inhibited growth of Hh pathway-driven medulloblastoma allografts derived from Ptch+/-p53-/- mice within a range of serum levels comparable to those achieved in treatment of human APL. Arsenic thus could be tested rapidly as a therapeutic agent in malignant diseases associated with Hh pathway activation and could be particularly useful in such diseases that are inherently resistant or have acquired resistance to cyclopamine mimics.

Large outbreaks of acute food-related poisoning, characterized by hepatic sinusoidal obstruction syndrome, hemorrhagic necrosis, and rapid liver failure, occur on a regular basis in some countries. They are caused by 1,2-dehydropyrrolizidine alkaloids contaminating locally grown grain. Similar acute poisoning can also result from deliberate or accidental consumption of 1,2-dehydropyrrolizidine alkaloid-containing herbal medicines, teas, and spices. In recent years, it has been confirmed that there is also significant, low-level dietary exposure to 1,2-dehydropyrrolizidine alkaloids in many countries due to consumption of common foods such as honey, milk, eggs, salads, and meat. The level of 1,2-dehydropyrrolizidine alkaloids in these foods is generally too low and too intermittent to cause acute toxicity. However, these alkaloids are genotoxic and can cause slowly developing chronic diseases such as pulmonary arterial hypertension, cancers, cirrhosis, and congenital anomalies, conditions unlikely to be easily linked with dietary exposure to 1,2-dehydropyrrolizidine alkaloids, especially if clinicians are unaware that such dietary exposure is occurring. This Perspective provides a comprehensive review of the acute and chronic toxicity of 1,2-dehydropyrrolizidine alkaloids and their potential to initiate certain chronic diseases, and suggests some associative considerations or indicators to assist in recognizing specific cases of diseases that may have resulted from dietary exposure to these hazardous natural substances. If it can be established that low-level dietary exposure 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.

Summary Plants form mutualistic symbioses with a variety of microorganisms including endophytic fungi that live inside the plant and cause no overt symptoms of infection. Some endophytic fungi form defensive mutualisms based on the production of bioactive metabolites that protect the plant from herbivores in exchange for a protected niche and nutrition from the host plant. Key elements of these symbioses are vertical transmission of the fungus through seed of the host plant, a narrow host range, and production of bioactive metabolites by the fungus. Grasses frequently form symbioses with endophytic fungi belonging to the family C lavicipitaceae. These symbioses have been studied extensively because of their significant impacts on insect and mammalian herbivores. Many of the impacts are likely due to the production of four classes of bioactive alkaloids – ergot alkaloids, lolines, indole‐diterpenes and peramine – that are distributed in different combinations among endophyte taxa. Several legumes, including locoweeds, are associated with a toxic syndrome called locoism as a result of their accumulation of swainsonine. Species in two genera were recently found to contain previously undescribed endophytic fungi ( U ndifilum spp., family P leosporaceae) that are the source of that toxin. The fungi are strictly vertically transmitted and have narrow host ranges. Some plant species in the morning glory family ( C onvolvulaceae) also form symbioses with endophytic fungi of the C lavicipitaceae that produce ergot alkaloids and, perhaps in at least one case, lolines. Other species in this plant family form symbioses with undescribed fungi that produce swainsonine. The swainsonine‐producing endophytes associated with the C onvolvulaceae are distinct from the U ndifilum spp. associated with locoweeds and the C lavicipitaceous fungi associated with Convolvulaceae. In the establishment of vertically transmitted symbioses, fungi must have entered the symbiosis with traits that were immediately useful to the plant. Bioactive metabolites are likely candidates for such pre‐adapted traits which were likely useful to the free‐living fungi as well. With future research, vertically transmitted fungi from diverse clades with narrow host ranges and that produce bioactive compounds are likely to be found as important mutualists in additional plants.

Contamination of grain with 1,2-dehydropyrrolizidine ester alkaloids (dehydroPAs) and their N-oxides is responsible for large incidents of acute and subacute food poisoning, with high morbidity and mortality, in Africa and in central and south Asia. Herbal medicines and teas containing dehydroPAs have also caused fatalities in both developed and developing countries. There is now increasing recognition that some staple and widely consumed foods are sometimes contaminated by dehydroPAs and their N-oxides at levels that, while insufficient to cause acute poisoning, greatly exceed maximum tolerable daily intakes and/or maximum levels determined by a number of independent risk assessment authorities. This suggests that there may have been cases of disease in the past not recognised as resulting from dietary exposure to dehydroPAs. A review of the literature shows that there are a number of reports of liver disease where either exposure to dehydroPAs was suspected but no source was identified or a dehydroPA-aetiology was not considered but the symptoms and pathology suggests their involvement. DehydroPAs also cause progressive, chronic diseases such as cancer and pulmonary arterial hypertension but proof of their involvement in human cases of these chronic diseases, including sources of exposure to dehydroPAs, has generally been lacking. Growing recognition of hazardous levels of dehydroPAs in a range of common foods suggests that physicians and clinicians need to be alert to the possibility that these contaminants may, in some cases, be a possible cause of chronic diseases such as cirrhosis, pulmonary hypertension and cancer in humans.

Abstract Cyclopamine, and its glycoside alkaloid X, along with jervine and veratrosine, induced cyclopian malformations in offspring born to ewes ingesting these compounds on the fourteenth day of gestation. Other steroidal alkaloids with somewhat similar structures and various other steroidal compounds including certain hormones and steroidal sapogenins did not induce the malformation.

Swainsonine, an indolizidine alkaloid with significant physiological activity, is an α-mannosidase and mannosidase II inhibitor that alters glycoprotein processing and causes lysosomal storage disease. Swainsonine is present in a number of plant species worldwide and causes severe toxicosis in livestock grazing these plants. Consumption of these plants by grazing animals leads to a chronic wasting disease characterized by weight loss, depression, altered behavior, decreased libido, infertility, and death. This review focuses on the three plant families and the associated taxa that contain swainsonine; the fungi that produce swainsonine, specifically the fungal endophytes associated with swainsonine-containing taxa; studies investigating the plant, endophyte, and swainsonine relationship; the influence of environmental factors on swainsonine concentrations in planta; and areas of future research.

An analytical method has been developed to measure the locoweed toxin, swainsonine, in locoweed plant material. Dry ground plant samples were extracted using a small-scale liquid/liquid extraction procedure followed by isolation of the swainsonine by solid phase extraction with a cation-exchange resin. Detection and quantitation of the swainsonine were accomplished using reversed phase high-performance liquid chromatography coupled to atmospheric pressure chemical ionization tandem mass spectrometry (LC-MS(2)). The limit of quantitation was estimated to be 0.001% swainsonine by weight in dry plant material, which corresponds to the lower threshold for toxicity of locoweeds. The method of analysis was applied to the analysis of Oxytropis sericea (white locoweed) and Oxytropis lambertii (Lambert locoweed) plant samples to measure the variability of individual plant swainsonine levels within populations and within species. Individual plant variability was found to be highly significant for both O. sericea and O. lambertii populations. The combined three-year mean swainsonine values taken from three populations of O. sericea ranged from 0.046% in Utah to 0.097% in a New Mexico population. Sixteen individual populations of O. lambertii were sampled from eight different U.S. states. Swainsonine was detected at levels >0.001% in only 5 of the 16 collection sites. Those populations of O. lambertii found to contain higher swainsonine levels were restricted to the most southern and western portion of its distribution, and all were identified as belonging to var. bigelovii, whereas var. articulata and var. lambertii samples contained swainsonine at levels <0.001%.

AIM: To validate gastric anti-ulcer properties of Rocket "Eruca sativa" on experimentally-induced gastric secretion and ulceration in albino rats. METHODS: Gastric acid secretion studies were undertaken using pylorus-ligated rats. Gastric lesions in the rats were induced by noxious chemicals including ethanol, strong alkalis, indomethacin and hypothermic restraint stress. The levels of gastric wall mucus (GWM), nonprotein sulfhydryls (NP-SH) and malondialdehyde (MDA) were also measured in the glandular stomach of rats following ethanol administration. The gastric tissue was also examined histologically. The extract was used in two doses (250 and 500 mg/kg body weight) in all experiments. RESULTS: In pylorus-ligated Shay rats, the ethanolic extract of Rocket "Eruca sativa L." (EER) significantly and dose-dependently reduced the basal gastric acid secretion, titratable acidity and ruminal ulceration. Rocket extract significantly attenuated gastric ulceration induced by necrotizing agents (80% ethanol, 0.2 mol/L NaOH, 25% NaCl), indomethacin and hypothermic restraint stress. The anti-ulcer effect was further confirmed histologically. On the other hand, the extract significantly replenished GWM and NP-SH levels, as well as the MDA level significantly reduced by extract pretreatment. CONCLUSION: Rocket extract possesses anti-secretory, cytoprotective, and anti-ulcer activities against experimentally-induced gastric lesions. The anti-ulcer effect is possibly through prostaglandin-mediated activity and/or through its anti-secretory and antioxidant properties.

Livestock poisoning, primarily liver damage, caused by consumption of plants containing 1,2-dehydropyrrolizidine ester alkaloids (dehydroPAs), and the corresponding N-oxides, is a relatively common occurrence worldwide. Because of the economic impact, extensive investigations of such episodes have been performed, particularly in Australia, South Africa the United States and, more recently, South America. Plant species most commonly involved are members of the families Boraginaceae, Asteraceae and Leguminosae. These may be native species that periodically flourish under particular climatic conditions or introduced species that thrive in the absence of natural control factors such as herbivory and competition. Contamination of grain crops with dehydroPA-producing plants has resulted in large-scale incidents of food poisoning in humans, with high morbidity and mortality, especially in Africa and in central and south Asia, with recent episodes in Afghanistan and possibly Ethiopia. Attention has recently focused on the potential for low levels of dehydroPAs to contaminate many food products in developed countries, possibly leading to progressive, chronic diseases that may not include overt hepatotoxicity. This overview examines the potential for better control of exposure and means of monitoring dehydroPA intake by extrapolation of knowledge gained from animal studies to the human situation.

Fetal movement, observed by ultrasound imaging, was significantly reduced (P less than or equal to 0.001) in pregnant goats gavaged with Conium seed and Nicotiana glauca and temporarily reduced with fresh Conium plant. Conium seed and Nicotiana glauca induced cleft palate and multiple congenital contractures in 100% of the kids born to pregnant goats gavaged with these plants. Multiple congenital contractures included torticollis, scoliosis, lordosis, arthrogryposis, rib cage anomalies, over extension, and flexure and rigidity of the joints. However, in goats gavaged with fresh Conium plant, fetal movement was inhibited for only about 5 hours after each individual dosage and gradually returned to control levels 12 hours after dosing. Fetal malformations in this group were limited from modest to moderate contractures of the front limbs, which resolved by 8-10 weeks post partum. No cleft palates were induced. Fetal movement was not inhibited in goats fed Lupinus caudatus and no cleft palates or multiple congenital contractures were induced in their offspring. The duration of the reduction in fetal movement appears to be an important factor in the severity and permanence of the deformities, particularly with cleft palate, spinal column defects, and severe joint deviation and fixation.

Excess consumption of selenium (Se) accumulator plants can result in selenium intoxication. The objective of the study reported here was to compare the acute toxicosis caused by organic selenium (selenomethionine) found in plants with that caused by the supplemental, inorganic form of selenium (sodium selenite). Lambs were orally administered a single dose of selenium as either sodium selenite or selenomethionine and were monitored for 7 days, after which they were euthanized and necropsied. Twelve randomly assigned treatment groups consisted of animals given 0, 1, 2, 3, or 4 mg of Se/kg of body weight as sodium selenite, or 0, 1, 2, 3, 4, 6, or 8 mg of Se/kg as selenomethionine. Sodium selenite at dosages of 2, 3, and 4 mg/kg, as well as selenomethionine at dosages of 4, 6, and 8 mg/kg resulted in tachypnea and/or respiratory distress following minimal exercise. Severity and time to recovery varied, and were dose dependent. Major histopathologic findings in animals of the high-dose groups included multifocal myocardial necrosis and pulmonary alveolar vasculitis with pulmonary edema and hemorrhage. Analysis of liver, kidney cortex, heart, blood, and serum revealed linear, dose-dependent increases in selenium concentration. However, tissue selenium concentration in selenomethionine-treated lambs were significantly greater than that in lambs treated with equivalent doses of sodium selenite. To estimate the oxidative effects of these selenium compounds in vivo, liver vitamin E concentration also was measured. Sodium selenite, but not selenomethionine administration resulted in decreased liver vitamin E concentration. Results of this study indicate that the chemical form of the ingested Se must be known to adequately interpret tissue, blood, and serum Se concentrations.

Two sheep and 1 cow were changed gradually from diets of alfalfa hay to diets that contained Halogeton glomeratus (halogeton). The halogeton used contained 12% (w/w) oxalic acid, and transitions to the halogeton diet were accompanied by marked (10-fold and greater) increases in the in vitro rate of oxalate metabolism by ruminal microbes. A transition period of 3 to 4 days appeared to be required for selection of a microbial population that rapidly degraded oxalate. Adapted animals tolerated the oxalate (.45 moles/day per sheep) and signs of toxicity were not observed. Increased rates of oxalate degradation were also observed in response to infusion of gradually increasing amounts of sodium oxalate into the rumens of two other sheep. These sheep however, died because they were unable to tolerate the .43 to .46 moles of oxalate infused per day. Oxalate degrading capacity was negligible in cell-free ruminal fluid from adapted sheep but was associated with fractions that contained bacterial cells. Degradation was inhibited by several antibiotics and by exposure of the incubation mixtures to oxygen. None of 99 pure cultures of bacteria isolated from an oxalate adapted sheep degraded oxalate.

Locoweeds (species of Oxytropis and Astragalus containing the toxin swainsonine) cause severe adverse effects on reproductive function in livestock. All aspects of reproduction can be affected: mating behavior and libido in males; estrus in females; abortion/embryonic loss of the fetus; and behavioral retardation of offspring. While much research has been done to describe and histologically characterize these effects, we have only begun to understand the magnitude of the problem, to define the mechanisms involved, or to develop strategies to prevent losses. Recent research has described the effects of locoweed ingestion in cycling cows and ewes. Briefly, feeding trials with locoweeds in cycling and pregnant cows have demonstrated ovarian dysfunction in a dose-dependent pattern, delayed estrus, extended estrous cycle length during the follicular and luteal phases, delayed conception (repeat breeders), and hydrops and abortion. Similar effects were observed in sheep. In rams, locoweed consumption altered breeding behavior, changed libido, and inhibited normal spermatogenesis. Neurological dysfunction also inhibited normal reproductive behavior, and some of these effects were permanent and progressive. In this article we briefly review the pathophysiological effects of locoweeds on reproduction.

This paper attempts to explain circumstances under which local may be or may not be best. Natural selection may lead to local adaptation (LA), or it may be constrained by gene flow, founder effects, small population size, genetic drift, and archetype. 'Specialist' species display greater LA than 'generalist' species. Local genotypes are to a certain extent transient, being a consequence of past historical genetic patterns. Two recent meta-analyses found that while local performance exceeded the performance of a randomly chosen nonlocal population in 71% of comparisons, general adaptation across environments was as frequent as LA. Genotypes for restoration are most likely to be effective if they are adapted to current site conditions. As environmental change accelerates, both globally and locally, exceptions to 'local is best' may increase. For these reasons, 'local is best' may be better thought of as a testable hypothesis rather than as a general assumption. While either local or nonlocal plant material may be most effective for restoration practice depending on individual circumstances, local material will continue to be the first choice for restoration practitioners whenever this option is feasible and effective.

Many species of lupines contain quinolizidine or piperidine alkaloids known to be toxic or teratogenic to livestock. Poison-hemlock (Conium maculatum) and Nicotiana spp. including N. tabacum and N. glauca contain toxic and teratogenic piperidine alkaloids. The toxic and teratogenic effects from these plant species have distinct similarities including maternal muscular weakness and ataxia and fetal contracture-type skeletal defects and cleft palate. It is believed that the mechanism of action of the piperidine and quinolizidine alkaloid-induced teratogenesis is the same; however, there are some differences in incidence, susceptible gestational periods, and severity between livestock species. Wildlife species have also been poisoned after eating poison-hemlock but no terata have been reported. The most widespread problem for livestock producers in recent times has been lupine-induced "crooked calf disease." Crooked calf disease is characterized as skeletal contracture-type malformations and occasional cleft palate in calves after maternal ingestion of lupines containing the quinolizidine alkaloid anagyrine during gestation days 40-100. Similar malformations have been induced in cattle and goats with lupines containing the piperidine alkaloids ammodendrine, N-methyl ammodendrine, and N-acetyl hystrine and in cattle, sheep, goats, and pigs with poison-hemlock containing predominantly coniine or gamma-coniceine and N. glauca containing anabasine. Toxic and teratogenic effects have been linked to structural aspects of these alkaloids, and the mechanism of action is believed to be associated with an alkaloid-induced inhibition of fetal movement during specific gestational periods. This review presents a historical perspective, description and distribution of lupines, poison-hemlock and Nicotiana spp., toxic and teratogenic effects and management information to reduce losses.

The study of plant secondary chemistry has been essential in understanding plant consumption by herbivores. There is growing evidence that secondary compounds also occur in floral rewards, including nectar and pollen. Many pollinators are generalist nectar and pollen foragers and thus are exposed to an array of secondary compounds in their diet. This review documents secondary compounds in the nectar or pollen of poisonous rangeland plants of the western United States and the effects of these compounds on the behavior, performance, and survival of pollinators. Furthermore, the biochemical, physiological, and behavioral mechanisms by which pollinators cope with secondary compound consumption are discussed, drawing parallels between pollinators and herbivores. Finally, three avenues of future research on floral reward chemistry are proposed. Given that the majority of flowering plants require animals for pollination, understanding how floral reward chemistry affects pollinators has implications for plant reproduction in agricultural and rangeland habitats.

To better characterize and compare the toxicity of and lesions produced by locoweed (Astragalus mollissimus) with those of swainsonine and a related glycoside inhibitor, castanospermine, 55 Sprague-Dawley rats were randomly divided into 11 groups of five animals each. The first eight groups were dosed via subcutaneous osmotic minipumps with swainsonine at 0, 0.1, 0.7, 3.0, 7.4, or 14.9 mg/kg/day or with castanospermine at 12.4 or 143.6 mg/kg/day for 28 days. The last three groups were fed alfalfa or locoweed pellets with swainsonine doses of 0, 0.9, or 7.2 mg/kg/day for 28 days. Swainsonine- and locoweed-treated rats gained less weight, ate less, and showed more signs of nervousness than did controls. Histologically, these animals developed vacuolar degeneration of the renal tubular epithelium, the thyroid follicular cells, and the macrophage-phagocytic cells of the lymph nodes, spleen, lung, liver, and thymus. Some rats also developed vacuolation of neurons, ependyma, adrenal cortex, exocrine pancreas, myocardial epicytes, interstitial cells, and gastric parietal cells. No differences in lesion severity or distribution were detected between animals dosed with swainsonine and those dosed with locoweed. Rats dosed with castanospermine were clinically normal; however, they developed mild vacuolation of the renal tubular epithelium, the thyroid follicular epithelium, hepatocytes, and skeletal myocytes. Special stains and lectin histochemical evaluation showed that swainsonine- and castanospermine-induced vacuoles contained mannose-rich oligosaccharides. Castanospermine-induced vacuoles also contained glycogen. These results suggest that 1) swainsonine causes lesions similar to those caused by locoweed and is probably the primary locoweed toxin; 2) castanospermine at high doses causes vacuolar changes in the kidney and thyroid gland; and 3) castanospermine intoxication results in degenerative vacuolation of hepatocytes and skeletal myocytes, similar to genetic glycogenosis.

Alkaloidal extracts from teratogenic lupins produced congenital deformities in calves typical of crooked calf disease when the extracts were administered to pregnant cows during the susceptible gestational period. These data and previous epidemiologic studies suggest that one of the four alkaloids in the preparation, anagyrine, is the responsible teratogen. Severity of the malformations was directly related to the level of anagyrine present in the preparations administered.