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PubMed1997

The glossy1 locus of maize and an epidermis-specific cDNA from Kleinia odora define a class of receptor-like proteins required for the normal accumulation of cuticular waxes.

Mutations at the glossy1 (gl1) locus of maize (Zea mays L.) quantitatively and qualitatively affect the deposition of cuticular waxes on the surface of seedling leaves. The gl1 locus has been molecularly cloned by transposon tagging with the Mutator transposon system. The epi23 cDNA was isolated by subtractive hybridization as an epidermis-specific mRNA from Senecio odora (Kleinia odora). The deduced amino acid sequence of the GL1 and EPI23 proteins are very similar to each other and to two other plant proteins in which the sequences were deduced from their respective mRNAs. These are the Arabidopsis CER1 protein, which is involved in cuticular wax deposition on siliques, stems, and leaves of that plant, and the protein coded by the rice expressed sequence tag RICS2751A. All four proteins are predicted to be localized in a membrane via a common NH2-terminal domain, which consists of either five or seven membrane-spanning helices. The COOH-terminal portion of each of these proteins, although less conserved, is predicted to be a water-soluble, globular domain. These sequence similarities indicate that these plant orthologs may belong to a superfamily of membrane-bound receptors that have been extensively characterized from animals, including the HIV co-receptor fusin (also termed CXCR4).

Algorithms↗
PubMed1993

Pyrrolizidine alkaloidosis in a two month old foal.

A foal, small and jaundiced from birth, succumbed after two months to chronic hepatic damage which was characterised by fibrosis, biliary ductular hyperplasia and the presence of pleomorphic hepatocytes containing either a single large nucleus or multiple nuclei. The fixed liver contained sulfur-bound pyrroles, which are derived from pyrrolizidine alkaloids. During pregnancy the pasture was heavily infested with the pyrrolizidine alkaloid-containing plant, Senecio madagascariensis. The hepatic disease affecting the foal appears to have been initiated by consumption of the alkaloids by the mare during gestation, and to represent a rare case of congenital pyrrolizidine alkaloidosis.

Animals↗
PubMed2006

Production of reactive oxygen species and reactive nitrogen species by angiosperm stigmas and pollen: potential signalling crosstalk?

Angiosperm stigmas exhibit high levels of peroxidase activity when receptive to pollen. To explore possible function(s) of this peroxidase activity we investigated amounts of reactive oxygen species (ROS), particularly hydrogen peroxide, in stigmas and pollen. Because nitric oxide (NO) was recently implicated in pollen tube growth, we also investigated amounts of NO in pollen and stigmas. Reactive oxygen species accumulation was assessed with confocal microscopy and light microscopy using ROS probes DCFH2-DA and TMB, respectively. NO was assayed using the NO probe DAF-2DA and confocal microscopy. Stigmas from various different angiosperms were found to accumulate ROS, predominantly H2O2, constitutively. In Senecio squalidus and Arabidopsis thaliana high amounts of ROS/H2O2 were localized to stigmatic papillae. ROS/H2O2 amounts appeared reduced in stigmatic papillae to which pollen grains had adhered. S. squalidus and A. thaliana pollen produced relatively high amounts of NO compared with stigmas; treating stigmas with NO resulted in reduced amounts of stigmatic ROS/H2O2. Constitutive accumulation of ROS/H2O2 appears to be a feature of angiosperm stigmas. This novel finding is discussed in terms of a possible role for stigmatic ROS/H2O2 and pollen-derived NO in pollen-stigma interactions and defence.

Arabidopsis↗
PubMed2005

Molecular analysis of a consortium of ruminal microbes that detoxify pyrrolizidine alkaloids.

Members of a consortium of bacteria, isolated from the rumen of sheep, that degrades pyrrolizidine alkaloids (PAs) found in tansy ragwort (Senecio jacobaea) were characterized. An enrichment of ruminal bacteria was isolated from a sample of ruminal fluid using standard anaerobic techniques. The PA degradative capacity of the enrichment was tested by spiking purified PA extract from tansy ragwort. Length heterogeneity analysis by PCR (LH-PCR) and restriction fragment length polymorphism (RFLP) analysis was used to identify members of the consortium. Phylogenetic analysis of the 16S rDNA gene revealed differing results based on the molecular method used. LH-PCR identified 7 different organisms in 3 groups while RFLP identified 6 organisms with differing banding patterns in 5 groups. After the phylogenetic analyses of both methods were combined, the combined isolates represented 6 groups. The majority of the members of this consortium are <97.0% homologous with known bacteria, indicating this consortium may contain novel organisms able to detoxify PAs found in tansy ragwort. Further understanding of the metabolic pathways used by this consortium to degrade PAs could lead to the use of the consortium as a probiotic therapy for livestock and horses afflicted with tansy ragwort toxicosis.

Animals↗
PubMed1984

Evaluation of amino acids, B vitamins and butylated hydroxyanisole as protective agents against pyrrolizidine alkaloid toxicity in rats.

Supplementation of the diets of rats with branched chain amino acids (BCAA: leucine, isoleucine, valine) did not alter their susceptibility to chronic poisoning by tansy ragwort (Senecio jacobaea), which contains hepatotoxic pyrrolizidine alkaloids (PA). Phenobarbital in the diet, which alters liver microsomal enzyme activity, also did not alter susceptibility to PA poisoning. A combination of butylated hydroxyanisole (BHA), cysteine and BCAA did increase (P less than .05) survival time of rats fed tansy ragwort. Dietary BHA and cysteine increased the survival time of rats injected with the PA monocrotaline, with evidence that addition of vitamin B12 and folic acid improved the effectiveness of this treatment. In a chronic feeding trial with tansy ragwort, a combination of BHA and cysteine increased (P less than .05) the survival times of rats, showing protective activity against PA poisoning. A mixture of B-complex vitamins, or vitamin B12-folic acid, was not effective in improving the response.

Amino Acids↗
PubMed1984

Teratogens in plants.

Many compounds synthesized by plants are known to be teratogenic in laboratory animals, but only a few have been shown by feeding trials to produce terata in livestock. Studies of plant teratogens affecting livestock have not moved forward in a systematic nor rapid way because of the logistical problems connected with such experiments in large animals. Information that has accumulated can be conveniently separated into three categories: (1) known teratogens in known teratogenic plants, (2) known teratogenic plants with unidentified teratogens, and (3) suspected teratogenic plants. Included in the first group are the teratogens from Lupinus, Veratrum, Conium and Leucaena genera; in the second group are included the Astragalus , Nicotiana and Trachymene genera; and in the third group are included Datura, Prunus , Sorghum and Senecio genera. Total available information in each case varies, but in a few instances considerable fundamental as well as practical information is now known. Research has provided enough information in a few instances to enable elimination of the practical problem or significant reduction in incidence.

Abnormalities, Drug-Induced↗
PubMed2002

Surveys of microfungi in a former industrial area in Duisburg-Nord.

One hundred and forty microfungi (Ascomycetes and Deuteromycetes) were collected in the "Landschaftspark Duisburg-Nord" located in North Rhine-Westphalia. New hosts for rarely found fungi are recorded for the first time. New for Germany are Massaria inquinans (Tode) De Not. and Nitschkia grevillei (Rhem) Nannf. on Acer pseudoplatanus L., Pirottaea nigrostriata Graddon on Artemisia vulgaris L., Ceratopycnis clematidis Höhn. on Clematis vitalba L., Dasyscyphus aff. humuli (W. Phillips) Dennis on Humulus lupulus L. and Leptosphaeria derasa (Berk. & Br.) Auersw. on Senecio inaequidens DC. New for North Rhine-Westphalia are Chaetosphaerella phaeostroma (Durieu & Mont.) E. Müller & Booth and Phomopsis platanoides (Cooke) Died. on Acer pseudoplatanus L., Microsphaeropsis pseudaspera Sutton, Mycosphaerella osborniae D. Hawksw. & Sivan. and Phomopsis oblita Sacc. on Artemisia vulgaris L., Leptosphaeria acuta (Fr.) P. Karst. and Leptosphaeria doliolum (Pers.) Ces. & De Not. on Bryonia dioica Jacq., Ophiobolus erythrosporus (Riess) G. Winter and Pleospora herbarum (Pers.) Rabenh. ex Ces. & De Not. on Dipsacus sylvestris (Huds), Keissleriella ocellata (Niessl) Bose on Hypericum perforatum L., Dactylaria aff. graminicola on Lolium perenne L., Siroplacodium aff. atrum on Oenothera beinnis L., Diatrypella favacea (Fr.) Sacc. on Prunus spec., Hapalosphaeria deformans (Syd.) Syd. and Microdiscula rubicola (Bres.) Höhn. on Rubus fructicosus agg. L., Cryptodiaporthe salicina (Pers.) Wehm. on Salix alba L. and Pleurophoma pleurospora (Sacc.) Höhn. on Salix caprea L.

Acer↗
PubMed1991

[Pilot study of the relationship of free amino acids in serum and in the cerebrospinal fluid of horses].

In a blind study serum and cerebrospinal fluid (CSF) of control horses and of horses in hepatic coma after chronic food intoxication with Senecio alpinus were collected simultaneously and the composition of free amino acids was determined. The hepatic encephalopathy index in serum (less than 1.65) and in CSF (less than 1.11) of liver patients was distinctly less than to the control values in serum (greater than 2.42) and in CSF (greater than 1.49). The serum concentrations of glutamic acid in hepatic coma were elevated five-fold in comparison to the controls. An indication of ammonia decontamination was that nearly ten-fold higher values of glutamine were found in the cerebrospinal fluids of patients than in serum. In comparison to controls the serum levels of glutamine in horses with hepatic encephalopathy were decreased by the factor 0.7.

Amino Acids↗
PubMed1990

Secondary gastric impaction associated with ragwort poisoning in three ponies.

Poisoning with Senecio jacobaea (ragwort) is a common cause of chronic liver disease in horses in Britain. The major clinical signs are the result of hepatic failure but gastric impaction has recently been associated with the disease. The present paper describes three cases of secondary gastric impaction associated with ragwort poisoning. In each case the impaction was the cause of death or necessitated euthanasia.

Animals↗
PubMed1988

Pyrrolizidine alkaloid-induced liver disease in horses: an early diagnosis.

Nine adult horses were fed alfalfa hay cubes containing approximately 10% Senecio vulgaris until all horses had consumed approximately the same amount of toxic components of S vulgaris, pyrrolizidine alkaloids (PA). The amount of PA consumed was determined by the amount that induced clinical signs of PA toxicosis in 3 horses. The 6 other horses were given similar amounts per kilogram of body weight. An initial decrease of feed intake was observed when horses' diets were changed from alfalfa cubes to alfalfa/Senecio cubes, and feed intake was decreased further over 89 to 98 days. From 50 to 159 days, body weight decreased in all horses. Liver disease was induced in all 9 horses after they ate an average of 233 +/- 9.2 mg of PA/kg of body weight. Eight horses died or were euthanatized. Treatment with branched chain amino acids had no effect on mortality, but appeared to reduce neurologic problems. Clinical signs of PA-induced liver disease included ataxia, head pressing, and decreased feed intake. Other clinical signs of toxicosis were observed individual horses, but did not develop in most horses. Megalocytic hepatopathy developed. Liver abnormalities proceeded as PA was consumed and were severe in 8 of 9 horses before clinical signs of toxicosis appeared. Sulfobromophthalein sodium clearance did not decrease until PA-induced liver disease was advanced. Bile acid (BA) concentrations increased to greater than or equal to 50 mumol/L, in the 8 horses that died. One horse had hepatopathy and increased BA concentration, but survived. In this horse, BA concentration peaked at 33 mumol/L and then decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids, Branched-Chain↗
PubMed1990

The Budd-Chiari syndrome and hepatic veno-occlusive disease. Recognition and treatment.

In a review of 29 patients who were surgically treated by combined hepatic and portal decompression for intractable ascites, 18 were identified as falling into the category of the Budd-Chiari syndrome, with varying causes. Of this group, 2 patients were distinguished by the classical hepatic venous endophlebitis described by Chiari and later by Bras et al. Recently, this disease entity has been recognized as being due to the toxic effects of pyrrolizidine alkaloids contained in the Senecio and Crotolaria plants. In the first of these two cases the patient had emigrated from Jamaica and was exposed to "bush trees," but no chemical measurements were done. The second patient had consumed a large amount of comfrey teas, which were shown to contain high levels of pyrrolizidine alkaloids. These two cases add further weight to the existing evidence of the toxic effect of these alkaloids, and also demonstrate the effectiveness of hepatic and portal decompression.

Beverages↗
PubMed1978

A sensitive analytical method for pyrrolizidine alkaloids. The mass spectra of retronecine derivatives.

The pyrrolizidine alkaloids in Senecio jacobaea can be hydrolyzed to the common base, retronecine, and derivatized to form the bistrifluoroacetate, bisheptafluorobutyrate, diacetate and bistrimethylsilyl ether. The analysis of the fluorinated compounds by electron capture provides sensitivity for detection of these alkaloids. The bond weakening effect in the ion formed on electron impact, between the allylic carbon and alkyl ester oxygen due to the electron withdrawing fluorinated groups of the ester, changes the driving force for fragmentation from the nitrogen alpha-cleavage reaction to a charge site migration. This yields alkyl-oxygen bond cleavage and formation of a stabilized allylic cation which is the base peak.

Chromatography, Gas↗
PubMed1993

Evaluation of the potential of riddelliine to induce unscheduled DNA synthesis, S-phase synthesis, or micronuclei following in vivo treatment with multiple doses.

Riddelliine (RID) is a pyrrolizidine alkaloid found in plants of the genera Crotalaria, Amsinckia, and Senecio in the United States. RID has been extensively studied in a wide variety of in vitro short-term genotoxicity tests and has yielded positive responses in most test systems; however, there are fewer data available on the effects of RID in in vivo assays and no data under repeat-dose regimens. We have evaluated the ability of RID to induce unscheduled DNA synthesis (UDS) in hepatocytes, S-phase synthesis (SPS) in hepatocytes, and micronuclei in bone marrow from animals dosed for 5 or 30 days in conjunction with prechronic toxicity testing conducted for the National Toxicology Program. Results of this study indicate that RID did not induce an increase in micronucleated polychromatic erythrocytes (PCE) in bone marrow of mice after 5 days of dosing or in PCE from rats or mice after 30 days of dosing. RID did not induce an increase in UDS in rat hepatocytes after 5 or 30 days of dosing, but it did induce an equivocal UDS response in male mice after both time points and a positive response in female mice after 30 days of dosing. RID induced significant elevations in SPS in rat hepatocytes after both 5 and 30 days of dosing, even at low doses. An increase in SPS was observed in male and female mouse hepatocytes, but only after 30 days of dosing. Rats and mice of both sexes showed a depression in SPS at higher doses. This effect may be a result of toxicity, which compromises the ability of the liver to regenerate. These results demonstrate that repeated administration of test chemicals may alter the genotoxic response to chemicals.

Animals↗
PubMed2007

X-ray microanalysis of biological material in the frozen-hydrated state by PIXE.

Elemental microanalysis of biological material in the frozen-hydrated state using in-vacuum proton induced X-ray emission is described for the first time. For this purpose, a commercially available cryotransfer system was modified and coupled to the experimental chamber of the nuclear microprobe (NMP). The analyzed material was frozen in propane cooled by liquid nitrogen, fractured, carbon coated, and transferred onto the cold stage (100 K) of the nuclear microprobe chamber. Micro-PIXE and simultaneous proton backscattering was performed using a 3 MeV proton beam. Quantitative results were obtained by the standardless method, and tested using 20% gelatin standards. Monitoring of the gas composition inside the system by means of mass spectrometry performed before, during, and after proton bombardment showed good stability of the analyzed material for proton currents not exceeding 150 pA. Average concentrations of light elements (C, N, O, and indirectly H) were also obtained by the proton backscattering technique. No losses of elements measurable by particle-induced X-ray emission (PIXE) during proton irradiation were found during repetitive, short analyses of the same micro areas of gelatin standards. Measurements of thick sections of selected plant and animal material in the frozen-hydrated state-leaf sections of the plant Senecio anomalochrous Hilliard (Asteraceae) and larvae of Chysolina pardalina Fabricius (Chrysomelidae)-showed very good preservation of morphology and elemental distribution. Limits of detection of the order of a few micro g g(-1) were obtained for most elements.

Animals↗
PubMed1995

Analysis of pyrrolizidine alkaloids: a competitive enzyme-linked immunoassay (ELISA) for the quantitative determination of some toxic pyrrolizidine alkaloids.

A highly sensitive and specific competitive enzyme-linked immunoassay (ELISA) for the determination of retrorsine, senecionine, and integerrimine in the nanogram range has been developed. Pyrrolizidine alkaloids were detected in Senecio rupestris. No cross-reactivity was seen with either retrosine N-oxide, otonecine alkaloids, or other macrocyclic pyrrolizidine alkaloids.

Animals↗
PubMed2003

Targeting enzymes involved in spermidine metabolism of parasitic protozoa--a possible new strategy for anti-parasitic treatment.

Sequencing data obtained from the Plasmodium, Anopheles gambiae and human genome projects provide a new basis for drug and vaccine development. One of the most characteristic features in the process of drug development against parasitic protozoa is target identification in a biological pathway. The next step must be a structure-based rational drug design if the target is not only present in the parasite. In mouse models of malaria, such drugs should be tested for efficacy of the new therapies. Here, we present data that pinpoint the existence of two enzymes of the polyamine pathway involved in spermidine metabolism in P. falciparum, i.e. deoxyhypusine synthase (DHS; EC 1.1.1.249) and homospermidine synthase (HSS; EC 2.5.1.45). Recent data obtained from the malaria genome databases showed that at least a putative gene encoding DHS is present in the parasite. Sequencing data from the P. falciparum genome project prove that the eukaryotic initiation factor eIF5A (the substrate for DHS) exists in P. falciparum. Here, we present the amino acid sequence of eIF5A from P. vivax, which causes tertiary malaria. EIF5A from P. vivax shows 82% nucleic acid and 97% amino acid identity to its homologue from P. falciparum. GC/MS data and inhibitor studies with agmatine prove that the triamine homospermidine occurs in the parasite. These data suggest a separate locus encoding HSS in P. falciparum. The hss gene recruits from the dhs gene in eukaryotes. Here, we present genomic DNA fragments obtained by amplification with primers of a conserved region (amino acid positions 550-1,043) between the putative P. falciparum DHS gene ( dhs) and the HSS gene ( hss) from the plant Senecio vulgaris (Asteraceae). The amplification product from different P. falciparum strains reveals differences in sequence identity, compared with the putative dhs gene from P. falciparum strain 3D7. Expression of the full-length clone and determination of HSS-specific activity will finally prove whether a separate region encoding HSS exists.

Alkyl and Aryl Transferases↗
PubMed2007

The male abdominal glands of Leucophaea maderae: chemical identification of the volatile secretion and sex pheromone function.

In Leucophaea maderae, male calling behavior involves the release of a sex pheromone from the abdominal sternal glands. An extract of sternal glands attracted conspecific females over a distance. The compounds present were identified as hydroxy-3-butan-2-one, (2R, 3R)-butanediol, senecioic acid, and (E)-2-octenoic acid. The same components are also present in male tergal glands. The identified compounds were tested on their own and in mixtures. Their biological function is discussed.

Animals↗
PubMedDate not supplied

Effects of the pyrrolizidine alkaloids senecionine, retrorsine and seneciphylline on aminopyrine N-demethylase activity on the rat liver S-10 fraction.

The effects of individual pyrrolizidine alkaloids on the mixed-function oxidase (MFO) enzyme aminopyrine N-demethylase were determined in rat liver 10 000 X g supernatant. The pyrrolizidine alkaloids, senecionine, seneciphylline and retrorsine were obtained from Senecio vulgaris. Senecionine and seneciphylline were found to be linear mixed-type inhibitors while retrorsine was found to be a competitive inhibitor of aminopyrine N-demethylase. The average Ki's +/- S.E. for senecionine, seneciphylline and retrorsine were 0.18 +/- 0.02, 0.33 +/- 0.06 and 0.92 +/- 0.05 mM, respectively.

Aminopyrine N-Demethylase↗