Cadmium toxicity symptoms and uptake mechanism in plants: a review / Sintomas de toxicidade de cádmio e mecanismo de absorção em plantas: uma revisão

Cadmium (Cd) is one of non-essential heavy metals which is released into environment naturally or anthropogenically. It is highly persistent toxic metals that are exceptionally distressing industrial and agriculture activities by contaminating soil, water and food. Its long-duration endurance in soil and water results in accumulation and uptake into plants, leading to the food chain. This becomes a serious global problem threatening humans and animals as food chain components. Living organisms, especially humans, are exposed to Cd through plants as one of the main vegetative food sources. This review paper is concentrated on the symptoms of the plants affected by Cd toxicity. The absorption of Cd triggers several seen and unseen symptoms by polluted plants such as stunted growth, chlorosis, necrosis and wilting. Apart from that, factors that affect the uptake and translocation of Cd in plants are elaborated to understand the mechanism that contributes to its accumulation. By insight of Cd accumulation, this review also discussed the phytoremediation techniques-phytoextraction, phytostimulation, phytostabilization, phytovolatization and rhizofiltration in bioremediating the Cd.

O cádmio (Cd) é um dos metais pesados ​​não essenciais que é liberado no meio ambiente de forma natural ou antropogênica. São metais tóxicos altamente persistentes que prejudicam excepcionalmente as atividades industriais e agrícolas, contaminando o solo, a água e os alimentos. Sua resistência de longa duração no solo e na água resulta em acúmulo e absorção pelas plantas, levando à cadeia alimentar. Isso se torna um sério problema global que ameaça humanos e animais como componentes da cadeia alimentar. Os organismos vivos, principalmente os humanos, são expostos ao Cd através das plantas como uma das principais fontes de alimento vegetativo. Este artigo de revisão concentra-se nos sintomas das plantas afetadas pela toxicidade do Cd. A absorção de Cd desencadeia vários sintomas visíveis e invisíveis por plantas poluídas, como crescimento atrofiado, clorose, necrose e murcha. Além disso, são elaborados fatores que afetam a absorção e translocação de Cd nas plantas para entender o mecanismo que contribui para o seu acúmulo. A partir do conhecimento do acúmulo de Cd, esta revisão também discutiu as técnicas de fitorremediação - fitoextração, fitoestimulação, fitoestabilização, fitovolatização e rizofiltração na biorremediação do Cd.

Spontaneous poisoning by Ateleia glazioviana (leg. Papilionoideae) in sheep and goats in the West region of Santa Catarina / Intoxicação espontânea por Ateleia glazioviana (Leg. papilionoideae) em ovinos e caprinos no Oeste de Santa Catarina

This study reported the epidemiological data and the clinical and pathological conditions of spontaneous poisoning by Ateleia glazioviana in sheep and goats in the West region of Santa Catarina. The small ruminants were located in a place where there was a large amount of young plants of A. glazioviana and showing signs of consumption. The stock of sheep was composed of 250 animals, of which 45 died. In the goat herd, there were 28 animals, and of these, 27 died, and one was sacrificed. The main clinical signs were weight loss, fatigue, slow-walk, and eventually submandibular and facial edema. Some animals were found dead, and others died suddenly after being moved. Abortions and the birth of weak lambs were also observed. In total, five sheep and one goat were necropsied. The main macroscopic lesions were associated to eccentric cardiac hypertrophy and moderate, multifocal white areas in the epicardium and myocardium. Two sheep showed marked edema in the subcutaneous tissue of the head and neck and it could be noted hydrothorax and hydroperitoneum and liver with a nutmeg-like appearance. Histological changes were relevant in the myocardium. They consisted of fibrosis and myofiber necrosis associated with macrophage infiltrate, multifocal, low and marked swelling of cardiomyocytes with loss of fibrillarystriae, and increased nuclear volume. In two sheep, there was still congenital hepatic, as well as marked centrilobular and diffuse areas.(AU)

Descrevem-se dados epidemiológicos, sinais clínicos e lesões da intoxicação espontânea por Ateleia glazioviana em ovinos e caprinos no Oeste de Santa Catarina. Os ovinos e caprinos se encontravam em um local que havia grande quantidade de A. glazioviana jovem e com sinais de consumo. O plantel de ovinos era composto por 250 animais, dos quais 45 morreram. No rebanho caprino haviam 28 animais e destes, 27 morreram e um foi sacrificado. Os principais sinais clínicos se caracterizaram por perda de peso, cansaço, caminhar lento e eventualmente edema submandibular e facial. Alguns foram encontrados mortos e outros morreram subitamente após serem movimentados. Abortos e nascimento de cordeiros fracos também foi observado. No total, cinco ovinos e um caprino foram necropsiados. As principais lesões macroscópicas foram hipertrofia excêntrica do coração e áreas brancas multifocais, moderadas, no epicárdio e miocárdio. Dois ovinos apresentaram edema acentuado no tecido subcutâneo da cabeça e pescoço, bem como hidrotórax, hidroperitôneo e fígado com aspecto de noz-moscada. As alterações histológicas foram relevantes no miocárdio e consistiram de áreas de fibrose e necrose de miofibras associada à infiltrado de macrófagos, multifocal, leve, além de tumefação acentuada de cardiomiócitos com perda das estrias fibrilares e aumento do volume nuclear. Em dois ovinos, havia ainda, congestão hepática, centrolobular, difusa.(AU)

Alucinaciones tras ingerir una infusión de una planta anticolinérgica con confirmación toxicológica / Hallucinations and toxicologic findings after ingestion of an infusion made from an anticholinergic plant

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Efecto de bacterias emulsificantes en la atenuación de la fitotoxicidad de suelos contaminados con petróleo intemperizado / Effect of emulsifying bacteria on phytotoxicity attenuation of soils contaminated with weathered petroleum hydrocarbons

Introducción: Las plantas y los microorganismos se han utilizado como bioindicadores de la toxicidad inducida por hidrocarburos presentes en los suelos. Objetivo: El presente trabajo evaluó la toxicidad de un Gleysol contaminado de origen con diferentes concentraciones de petróleo intemperizado, recolectado en la Venta Tabasco (México), en el crecimiento de Clitoria ternatea, y la atenuación de la fitotoxicidad con la inoculación de bacterias emulsificantes. Metodología: Se usaron suelos con 50 y 150 g HTPI kg-1, y un suelo testigo con 0.15 g HTPI kg-1 (origen biogénico), y la inoculación de seis bacterias emulsificantes y su combinación (consorcio). La fitotoxicidad de los HTPI se evaluó considerando la altura, la biomasa seca (radical, aérea y total), el área foliar, el área foliar específica, y la eficiencia del fotosistema II (EPSII), a los 30 días. Resultados: Los HTPI no afectaron la altura, pero el suelo con 50 g HTPI kg-1 redujo la biomasa seca radical y total, y el área foliar con respecto a las plantas en los suelos testigo y con 150 g HTPI kg-1. La cepa Sml (Stenotrophomonas maltophilia C10S1) incrementó significativamente la biomasa seca total; la cepa Ro (Raoultella ornithinolyticaC5S3) produjo mayor área foliar específica con respecto a plantas no inoculadas. En el suelo testigo, el consorcio bacteriano estimuló la altura; las cepas Sm (Serratia marcescens C11S1) y Sm2 (S. marcescens C7S3) mejoraron la altura y el área foliar específica con respecto a plantas no inoculadas, en el suelo con 50 g HTPI kg-1. En el suelo con 150 g HTPI kg-1, las cepas Spa (Stenotrophomonas pavanii C5S3F) y Cfr (Citrobacter freundii C4S3) incrementaron la biomasa seca radical y aérea, respectivamente. La EPSII no fue afectada por la contaminación de los suelos. Las bacterias emulsificantes redujeron la fitotoxicidad de HTPI, pero dependiendo de su contenido en los suelos. Conclusiones: El suelo con 50 g HTPI kg-1 mostró mayor toxicidad en el crecimiento de las plantas. La inoculación bacteriana favoreció el crecimiento, producción de biomasa, y área foliar en el suelo con 150 g HTPI kg-1. La EPSII no fue afectada por la presencia de HTPI en el suelo.

Introduction: Plants and microorganisms have been used as bioindicators to evaluate the toxicity of hydrocarbons in soils. Objective: This study evaluates the toxicity of a chronically-contaminated Gleysol with several concentrations of weathered petroleum hydrocarbons (WPH), collected from La Venta, Tabasco (Mexico), on the growth of Clitoria ternatea and the phytoxicity attenuation due to inoculation of emulsifying bacteria. Methods: Soils with 50 and 150 g WPH kg-1, and control soil with 0.15 g WPH kg-1 (biogenic origin) were utilized, as well as the inoculation of six emulsifying bacteria and their combination (consortium). The WPH-phytotoxicity was evaluated by considering plant height, dry biomass production (root, shoot, and total), leaf area, specific leaf area, and the efficiency of photosystem II (EPSII), after 30 days. Results: WPH did not affect plant height, but soil with 50 g WPH kg-1 diminished root and total dry weight, and leaf area, when compared to both control soil and soil with 150 g WPH kg-1. The strain Sml (Stenotrophomonas maltophilia C10S1) significantly increased shoot and total dry weight, while the strain Ro (Raoultella ornithinolytica C5S3) produced higher specific leaf area relative to uninoculated plants. In control soil, the bacterial consortium stimulated plant height. The strains Sm (Serratia marcescens C11S1)and Sm2 (S. marcescens C7S3) improved plant height and specific leaf area when compared to uninoculated plants in soil with 50 g WPH kg-1. In soil with 150 g WPH kg-1, strains Spa (Stenotrophomonas pavanii C5S3F)and Cfr (Citrobacter freundii C4S3)enhanced root and shoot dry weight, respectively. The EPSII was unaffected by soil contamination. Emulsifying bacteria reduced the phytotoxic effects of WP, but depending on the content of WPH in soils. Conclusions: Soil with 50 g WPH kg-1 showed the greatest phytotoxic effects on plant growth. Bacterial inoculation favored growth, biomass production and leaf area in soil with 150 g WPH kg-1. The EPSII was not affected by WPH in soils.

Plants with neurotoxic potential in undernourished subjects.

The consumption by humans of plants with potential to induce neurological disorders is widespread, but overt disease surfaces only when the subject's toxic threshold is exceeded. Excessive intake arising from food dependency in the setting of hunger, chronic undernutrition, vitamin deficiency, inadequate detoxication, or other individual susceptibility, can trigger acute encephalopathy (lychee, ackee fruits), sub-acute spastic paraparesis (grasspea, cassava root/leaves) or ataxic neuropathy (cassava root flour). While these disorders are very rarely encountered in high-income countries, they are not only common among impoverished populations but also often occur as outbreaks that impact a significant proportion of an affected community. Unfamiliarity with the adverse effects of plant toxins has sometimes led to the mistaken attribution of nutritional neurotoxic disease to a neurotropic viral or synthetic pesticidal etiology. The combination of human population growth, food and water insecurity, poverty and, with climate change, increased dependency on environmentally tolerant plants with neurotoxic potential, predictably may result in an increased prevalence of nutritional neurotoxic disorders, especially in certain parts of Africa and Asia.

Pyrrolizidine Alkaloids: Chemistry, Pharmacology, Toxicology and Food Safety.

Pyrrolizidine alkaloids (PA) are widely distributed in plants throughout the world, frequently in species relevant for human consumption. Apart from the toxicity that these molecules can cause in humans and livestock, PA are also known for their wide range of pharmacological properties, which can be exploited in drug discovery programs. In this work we review the current body of knowledge regarding the chemistry, toxicology, pharmacology and food safety of PA.

A Gas Chromatography-Mass Spectrometry Method for the Detection and Quantitation of Monofluoroacetate in Plants Toxic to Livestock.

Monofluoroacetate (MFA) is a potent toxin that occurs in over 50 plant species in Africa, Australia, and South America and is responsible for significant livestock deaths in these regions. A gas chromatography-mass spectrometry (GC-MS) method for the analysis of MFA in plants based on the derivatization of MFA with n-propanol in the presence of sulfuric acid to form propyl fluoroacetate was developed. This method compared favorably to a currently employed high-performance liquid chromatography-mass spectrometry (HPLC-MS) method for the analysis of MFA in plants. The GC-MS method was applied to the analysis of MFA in herbarium specimens of Fridericia elegans, Niedenzuella stannea, N. multiglandulosa, N. acutifolia, and Aenigmatanthera lasiandra. This is the first report of MFA being detected in F. elegans, N. multiglandulosa, N. acutifolia, and A. lasiandra, some of which have been reported to cause sudden death or that are toxic to livestock.

Plant Secondary Metabolites as Rodent Repellents: a Systematic Review.

The vast number of plant secondary metabolites (PSMs) produced by higher plants has generated many efforts to exploit their potential for pest control. We performed a systematic literature search to retrieve relevant publications, and we evaluated these according to PSM groups to derive information about the potential for developing plant-derived rodent repellents. We screened a total of 54 publications where different compounds or plants were tested regarding rodent behavior/metabolism. In the search for widely applicable products, we recommend multi-species systematic screening of PSMs, especially from the essential oil and terpenoid group, as laboratory experiments have uniformly shown the strongest effects across species. Other groups of compounds might be more suitable for the management of species-specific or sex-specific issues, as the effects of some compounds on particular rodent target species or sex might not be present in non-target species or in both sexes. Although plant metabolites have potential as a tool for ecologically-based rodent management, this review demonstrates inconsistent success across laboratory, enclosure, and field studies, which ultimately has lead to a small number of currently registered PSM-based rodent repellents.

Why do we like sweet taste: A bitter tale?

Sweet is widely considered to be one of a small number of basic or primary taste qualities. Liking for sweet tasting substances is innate, although postnatal experiences can shape responses. The power of sweet taste to induce consumption and to motivate behavior is profound, suggesting the importance of this sense for many species. Most investigators presume that the ability to identify sweet molecules through the sense of taste evolved to allow organisms to detect sources of readily available glucose from plants. Perhaps the best evidence supporting this presumption are recent discoveries in comparative biology demonstrating that species in the order Carnivora that do not consume plants also do not perceive sweet taste due to the pseudogenization of a component of the primary sweet taste receptor. However, arguing against this idea is the observation that the sweetness of a plant, or the amount of easily metabolizable sugars contained in the plant, provides little quantitative indication of the plant's energy or broadly conceived food value. Here it is suggested that the perceptual ratio of sweet taste to bitter taste (a signal for toxicity) may be a better gauge of a plant's broadly conceived food value than sweetness alone and that it is this ratio that helps guide selection or rejection of a potential plant food.

Checking the Biocompatibility of Plant-Derived Metallic Nanoparticles: Molecular Perspectives.

Understanding the biocompatibility of metallic nanoparticles (MNPs) is pivotal for biomedical applications. The biocompatibility of plant-derived MNPs has been mostly attributed to capped plant molecules. This claim seems to be straightforward but lacks conclusive evidence. The capped phytochemicals and the metallic core might have decisive and individual roles in imparting the overall biocompatibility. Whether capped phytochemicals really make sense in diminishing the toxicity effect of the otherwise naked or metallic core needs further analysis. Here, we readdress the biocompatibility of plant-derived MNPs with references to contemporary cellular assays, different reactants for green synthesis, possible epigenetic involvement, and nanobiocompatibility at the molecular level. Finally, we discuss relevant in vivo studies and large-scale production issues.

Tóxicos vegetales: un problema aún vigente / Poisonous plants: An ongoing problema

INTRODUCCIÓN: La consulta por ingesta de plantas es poco habitual en los Servicios de Urgencias pediátricas pero puede conllevar una elevada toxicidad. La formación sobre toxicología botánica del personal sanitario suele ser escasa y puede resultar difícil llegar al diagnóstico o establecer el tratamiento adecuado. OBJETIVO: Estudiar las características epidemiológicas y clínicas de las intoxicaciones por ingesta de sustancias vegetales con el fin de aumentar su conocimiento en el personal sanitario. MATERIALES Y MÉTODOS: Estudio descriptivo retrospectivo de los pacientes atendidos por ingesta de sustancia vegetal, entre enero del 2008 y diciembre del 2012, en el Servicio de Urgencias de un hospital materno-infantil de tercer nivel. RESULTADOS: Durante el periodo de estudio fueron atendidos 18 pacientes con ingesta de un posible tóxico vegetal. En 14 casos la ingesta se consideró potencialmente tóxica: retama, adelfa, muérdago, acebillo, judía vulgar (2), tomate de Jerusalén, ricino (2), estramonio, potus, marihuana y setas con toxicidad digestiva (2). De estos, en 10 la ingesta fue no intencionada, 2 casos pueden enmarcarse en el maltrato infantil, se produjo un caso con fin recreativo y otro con fin suicida. Destacaron por su toxicidad las ingestas de adelfa, ricino y estramonio. CONCLUSIONES: La potencial gravedad de la ingesta de sustancias vegetales y la variedad de los mecanismos de exposición al tóxico obligan al pediatra a tener presente esta posibilidad y estar preparado para su diagnóstico y manejo. Es necesario diseñar medidas preventivas específicas, como la información a las familias o la regulación de la presencia de plantas tóxicas en zonas de recreo

INTRODUCTION: A medical visit for plant ingestion is rare in the pediatric emergency services but may involve a high toxicity. The botanical toxicology training of health staff is often very limited, and it can be difficult to make a diagnosis or decide on the appropriate treatment. OBJECTIVE: To study the epidemiological and clinical characteristics of poisoning due to plant ingestion in order to increase the knowledge of the health professional. MATERIAL AND METHODS: A descriptive retrospective study was conducted on patients seen in a pediatric emergency department after the ingestion of plant substances from January 2008 to December 2012. RESULTS: During the period of study, 18 patients had ingested possible toxic plants. In 14 cases, it was considered to be potentially toxic: broom, oleander, mistletoe, butcher's-broom, and vulgar bean (2), Jerusalem tomato, castor (2), Jimson weed, potus, marijuana, and mushrooms with digestive toxicity (2). Among the potentially toxic cases, the ingestion was accidental in 10 patients, 2 cases were classed as infantile mistreatment, 1 case had recreational intention, and another one suicidal intentions. The ingestion of oleander, castor and Jimson weed had major toxicity. CONCLUSIONS: The potential gravity of the ingestion of plant substances and the variety of the exposure mechanism requires the pediatrician to bear in mind this possibility, and to be prepared for its diagnosis and management. Specific preventive information measures need to be designed for the families and for the regulation of toxic plants in playgrounds

Ecotoxicity studies of antifungal metabolites of Bacillus sp. IBA 33 / Estudios de la ecotoxicidad de metabolitos antifúngicos de Bacillus sp. IBA 33

The increments of plant diseases caused by the proliferation of fungicide-resistant pathogens intensified the research of new active metabolites against them. The study of biological methods as an alternative to chemical control has reach relevance in recent years. It has been suggested that the use of metabolites from Bacillus, is an alternative or supplementary method to chemical plant protection, if they are not toxic for the consumers and environmentally friendly. The toxicity of different concentrations of antifungal metabolites produced by Bacillus sp. IBA 33 was evaluated. Their ability to induce cytotoxic effects was investigated by different tests as hemolysis, and Artemia salina and Allium cepa L immobilization. With 2.56 mg/ml of antifungal metabolites hemolysis reached 24.07%, to 1.28 mg/ml was 14%. HC50 was 10.41 mg/ml. A. salina nauplii exposed to 3.2, 1.6 and 0.8 mg/ml of antifungal metabolites showed 80, 20 and 10% of mortality respectively; LD50 was 2.24 mg/ml. In Allium cepa L test after 72 h of treatment, the roots lengths were 8.75, 10.35 and 23.75 mm with 3.2, 1.6 and 0.8 mg/ml of antifungal metabolites respectively. The EC50 was 0.078 mg/ml. After 144 h the EC50 was 4.11 mg/ml. Only with 3.2 mg/ml of metabolites, chromosomal aberrations, cytoplasm vacuolization and decentralization of nuclei were observed in the cells of Allium cepa L. No micronuclei were detected. Under the experimental conditions, the antifungal metabolites concentrations assayed are considered non toxic (AU)

El incremento de enfermedades de plantas causado por la proliferación de patógenos resistentes a fungicidas intensificó la investigación de nuevos metabolitos activos contra ellos. El estudio de métodos biológicos como una alternativa al control químico ha alcanzado relevancia en años recientes. Se ha sugerido que el uso de metabolitos de Bacillus, es una alternativa o un método suplementario a la protección química de las plantas, siempre y cuando ellos no sean tóxicos para los consumidores y sean amigables para el medio ambiente. Se ha evaluado la toxicidad de diferentes concentraciones de metabolitos antifúngicos producidos por Bacillus sp. IBA33. Se investigó su capacidad para inducir efectos citotóxicos mediante diferentes tests como hemólisis e inmovilización de Artemia salina y Allium cepa L. Con 2.56 mg/ml de metabolitos antifúngicos la hemólisis alcanzó 24.07%, para 1.28 mg/ml fue 14%. La HC50 fue 10.41 mg/ml. Nauplios de Artemia salina expuestos a 3.2; 1.6 y 0.8 mg/ml de metabolitos antifúngicos mostraron 80; 20 y 10% de mortalidad respectivamente después de 24 h de tratamiento; la LD50 fue 2.24 mg/ml. En el test de Allium cepaL después de 72 h de tratamiento, la longitud de las raíces fueron 8.75; 10.35 y 23.75 mm con 3.2; 1.6 y 0.8 mg/ml de metabolitos antifúngicos respectivamente, con una EC50 de 0.078 mg/ml. Después de 144 h la EC50 fue 4.11 mg/ml. Solamente con 3.2 mg/ml de metabolitos fueron observadas aberraciones cromosómicas, vacualización y descentralización de los núcleos en las células de Allium cepa L. No se observaron micronúcleos. Bajo las condiciones experimentales, las concentraciones de metabolitos antifúngicos ensayadas son consideradas no tóxicas

Phototoxicity of herbal plants and herbal products.

Plants are used by humans in daily life in many different ways, including as food, herbal medicines, and cosmetics. Unfortunately, many natural plants and their chemical constituents are photocytotoxic and photogenotoxic, and these phototoxic phytochemicals are widely present in many different plant families. To date, information concerning the phototoxicity and photogenotoxicity of many plants and their chemical constituents is limited. In this review, we discuss phototoxic plants and their major phototoxic constituents; routes of human exposure; phototoxicity of these plants and their constituents; general mechanisms of phototoxicity of plants and phototoxic components; and several representative phototoxic plants and their photoactive chemical constituents.

Coumestrol and its metabolite in mares' plasma after ingestion of phytoestrogen-rich plants: potent endocrine disruptors inducing infertility.

Phytoestrogens exist in plants that are present in forages fed to horses. They may compete with 17-ß estradiol and influence the estrous cycle. Therefore, the objective was to determine whether coumestrol from clover-mixed pastures is present in mare's plasma after their ingestion (experiment I), and when this phytoestrogen was present in mare's plasma after ingestion (experiment II). The effect of a long-term ingestion of phytoestrogens on estrous cycle disruption was assessed (experiment III; clinical case). Experiment I was carried out in nonpregnant anestrous and cyclic Lusitano mares (n = 14) kept on clover and grass-mixed pastures, and supplemented with concentrate and hay or cereal straw. Blood and feedstuff were obtained from November to March. In experiment II, stabled cyclic Lusitano mares (n = 6) were fed for 14 days with increasing amounts of alfalfa pellets (250 g to 1 kg/day). Sequential blood samples were obtained for 8 hours after feed intake on Day 0 (control) and on Days 13 and 14 (1 kg/day alfalfa pellets). Experiment III mares were fed with a mixture of alfalfa and clover haylage for 5 months (group 1; n = 4) or for 9 months (group 2; n = 12). Estrous cycle was determined on the basis of plasma estradiol (E2), progesterone (P4), and ultrasound (experiment III). Concentrations of phytoestrogen coumestrol and its metabolite methoxycoumestrol were determined by high-performance liquid chromatography coupled with mass spectrometry. Phytoestrogens decreased in pasture from November until March (P < 0.01) (experiment I), but were always detected in mares' plasma. In experiment II, plasma-conjugated forms of coumestrol and methoxycoumestrol were higher on Days 13 and 14 than in control (P < 0.05). The highest concentrations of conjugated form of coumestrol were at 1.5 and 4 hours (P < 0.001), whereas its free forms peaked at 1 and at 3.5 hours after ingestion (P < 0.05). Methoxycoumestrol-conjugated form concentration was the highest at 1.5 and 5 hours (P < 0.001), whereas its free form peaked at 1 hour (P < 0.05) and at 1.5 hours (P < 0.001). Long-term intake of coumestrol caused lack of ovulation, uterine edema, and uterine fluid accumulation (experiment III). Coumestrol and methoxycoumestrol in both forms were higher in group 2 (while still ingesting haylage) than in group 1, after haylage withdrawal (P < 0.001). These data show that in the mare, coumestrol and its metabolite increase in blood after ingestion of estrogenic plants and can influence reproduction in mares as potent endocrine disruptors.

Cytochrome P450 2B diversity and dietary novelty in the herbivorous, desert woodrat (Neotoma lepida).

Detoxification enzymes play a key role in plant-herbivore interactions, contributing to the on-going evolution of ecosystem functional diversity. Mammalian detoxification systems have been well studied by the medical and pharmacological industries to understand human drug metabolism; however, little is known of the mechanisms employed by wild herbivores to metabolize toxic plant secondary compounds. Using a wild rodent herbivore, the desert woodrat (Neotoma lepida), we investigated genomic structural variation, sequence variability, and expression patterns in a multigene subfamily involved in xenobiotic metabolism, cytochrome P450 2B (CYP2B). We hypothesized that differences in CYP2B expression and sequence diversity could explain differential abilities of woodrat populations to consume native plant toxins. Woodrats from two distinct populations were fed diets supplemented with either juniper (Juniperus osteosperma) or creosote bush (Larrea tridentata), plants consumed by woodrats in their respective desert habitats. We used Southern blot and quantitative PCR to determine that the genomic copy number of CYP2B in both populations was equivalent, and similar in number to known rodent copy number. We compared CYP2B expression patterns and sequence diversity using cloned hepatic CYP2B cDNA. The resulting sequences were very diverse, and clustered into four major clades by amino acid similarity. Sequences from the experimental treatments were distributed non-randomly across a CYP2B tree, indicating unique expression patterns from woodrats on different diets and from different habitats. Furthermore, within each major CYP2B clade, sequences shared a unique combination of amino acid residues at 13 sites throughout the protein known to be important for CYP2B enzyme function, implying differences in the function of each major CYP2B variant. This work is the most comprehensive investigation of the genetic diversity of a detoxification enzyme subfamily in a wild mammalian herbivore, and contributes an initial genetic framework to our understanding of how a wild herbivore responds to critical changes in its diet.