Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SENECIO”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed2003

Phylogeny reconstruction in the gap between too little and too much divergence: the closest relatives of Senecio jacobaea (Asteraceae) according to DNA sequences and AFLPs.

The species composition and molecular phylogeny of Senecio sect. Jacobaea (Asteraceae; Senecioneae) were studied to identify the closest relatives of Senecio jacobaea. Maximum parsimony and Bayesian inference analyses of DNA sequence data of the plastid (the trnT-L igs, the trnL intron, two parts of the trnK intron, and the psbA-trnH igs) and nuclear genome (ITS1, 5.8S, and ITS2) showed these markers to be suitable to assess the species composition of sect. Jacobaea, identifying 24 species as members of this section. Of these, nine species were not previously assigned to the section. The selected DNA sequence regions, however, showed too little sequence divergence to be optimal for phylogenetic inference within sect. Jacobaea. In contrast, AFLPs proved to be too variable to be used to study relationships between the basal lineages in sect. Jacobaea. Nonetheless, these markers are very useful to study the phylogeny of S. jacobaea and its closest relatives. The combined use of DNA sequence data and AFLPs allowed us to take a major step towards resolving phylogenetic relationships in sect. Jacobaea, identifying Senecio alpinus, Senecio pancicii and Senecio subalpinus (using DNA sequence data) or Senecio chrysanthemoides (using AFLPs) as the closest relatives of S. jacobaea.

Base Sequence↗
PubMedDate not supplied

Biological properties of different extracts of two Senecio species.

This study reports on the antioxidant, anti-diabetic and cytotoxic properties of different extracts of two Senecio species, Senecio vulgaris and Senecio inaequidens. Leaves of the latter are used as food in specific populations of Southern of Africa. Both investigated species of Senecio were found to possess different biological activities. S. inaequidens extracts possess a greater antioxidant activity in comparison with S. vulgaris. Highly significant and dose-dependent performance was obtained with the methanolic and dichloromethane extracts of S. vulgaris and the n-hexane extract of S. inaequidens regarding cytotoxic activity on cancer cell lines, while none of the extracts demonstrated activity on normal cell line MRC-5. Both Senecio species also show appreciable alpha-amylase inhibition, particularly the methanolic and dichloromethane extracts, and this may confer anti-diabetic properties on the extract.

Antineoplastic Agents↗
PubMed2005

Oxidative stress in the erythrocytes of cattle intoxicated with Senecio sp.

BACKGROUND: Intoxication caused by Senecio sp is characterized by irreversible damage to liver cells and may be associated with oxidative stress. OBJECTIVES: The aim of this study was to evaluate the effects of intoxication by Senecio sp on lipoperoxidation, antioxidant defenses, and the osmotic resistance of erythrocytes in cattle. METHODS: Blood samples from 30 intoxicated animals (group 1) and 30 healthy animals (group 2) were analyzed. The diagnosis of poisoning by Senecio sp was based on histopathologic lesions verified through hepatic biopsy. The following biochemical parameters of oxidative stress in the erythrocytes were determined: thiobarbituric acid-reactive substances (TBARS), copper-zinc superoxide dismutase (CuZnSOD) activity, and nonprotein sulfhydryl (NPSH) groups. Erythrocyte osmotic fragility also was evaluated. RESULTS: TBARS concentration and CuZnSOD activity were significantly (P <.001) higher in group 1 when compared with group 2. The concentration of erythrocyte NPSH groups was significantly (P <.03) lower in group 1 when compared with group 2. Osmotic fragility was more pronounced in the erythrocytes of group 1 when compared with group 2 (P < .001). CONCLUSIONS: The results of this study indicate that poisoning by Senecio sp causes an increase in lipoperoxidation, oxidation of NPSH groups, and consequently, oxidative stress in bovine erythrocytes that may contribute to hemolysis. These findings may contribute to a better understanding of the mechanisms involved in cell damage in animals intoxicated by Senecio sp.

Animals↗
PubMed2005

Frequent gain and loss of pyrrolizidine alkaloids in the evolution of Senecio section Jacobaea (Asteraceae).

Pyrrolizidine alkaloids (PAs) of the macrocyclic senecionine type are secondary metabolites characteristic for most species of the genus Senecio (Asteraceae). These PAs are deterrent and toxic to most vertebrates and insects and provide plants with a chemical defense against herbivores. We studied the PA composition of 24 out of 26 species of Senecio section Jacobaea using GC-MS. The PA profiles of eight of these species have not been studied before and additional PAs were identified for most other species that were included in previous studies. With one exception (senecivernine) all 26 PAs identified in sect. Jacobaea can be regarded as derivatives of the biosynthetic backbone structure senecionine. Based on the PA profiles of the species of sect. Jacobaea and the results of previous tracer studies, we constructed two hypothetical biosynthetic scenarios of senecionine diversification. Both scenarios contain two major reactions: the conversion of the necine base moiety retronecine into the otonecine moiety and site-specific epoxidations within the necic acid moiety. Further reactions are site-specific hydroxylations, sometimes followed by O-acetylations, site-specific dehydrogenations, E, Z-isomerizations, and epoxide hydrolysis and chlorolysis. The GC-MS data and both biosynthetic scenarios were subsequently used to study the evolution of PA formation in sect. Jacobaea by reconstructing the evolutionary history of qualitative PA variation in this section. This was achieved by optimizing additive presence/absence data of PAs and types of enzymatic conversions on a maximum parsimony cladogram of section Jacobaea inferred from DNA sequence and morphological data. Besides showing large intra- and interspecific variation, PA distribution appears to be largely incidental within the whole clade. These results together with the finding that all but one of the PAs identified in sect. Jacobaea are also present in species of other sections of Senecio indicate that differences in PA profiles in Senecio can not be explained by the gain and loss of PA specific genes, but rather by a transient switch-off and switch-on of the expression of genes encoding PA pathway-specific enzymes.

Biological Evolution↗
PubMed1995

Chloroplast DNA variation and the recent radiation of the giant senecios (Asteraceae) on the tall mountains of eastern Africa.

Chloroplast DNA restriction-site variation was surveyed among 40 accessions representing all 11 species of giant senecios (Dendrosenecio, Asteraceae) at all but one known location, plus three outgroup species. Remarkably little variation (only 9 variable sites out of roughly 1000 sites examined) was found among the 40 giant senecio accessions, yet as a group they differ significantly (at 18 sites) from Cineraria deltoidea, the closest known relative. This pattern indicates that the giant senecios underwent a recent dramatic radiation in eastern Africa and evolved from a relatively isolated lineage within the Senecioneae. Biogeographic interpretation of the molecular phylogeny suggests that the giant senecios originated high on Mt. Kilimanjaro, with subsequent dispersion to the Aberdares, Mt. Kenya, and the Cherangani Hills, followed by dispersion westward to the Ruwenzori Mountains, and then south to the Virunga Mountains, Mt. Kahuzi, and Mt. Muhi, but with dispersion back to Mt. Elgon. Geographic radiation was an important antecedent to the diversification in eastern Africa, which primarily involved repeated altitudinal radiation, both up and down the mountains, leading to morphological parallelism in both directions. In general, the plants on a given mountain are more closely related to each other than they are to plants on other mountains, and plants on nearby mountains are more closely related to each other than they are to plants on more distant mountains. The individual steps of the geographic radiation have occurred at various altitudes, some clearly the result of intermountain dispersal. The molecular evidence suggests that two species are extant ancestors to other species on the same or nearby mountains.

Africa, Eastern↗
PubMed2005

Development of anonymous cDNA microarrays to study changes to the Senecio floral transcriptome during hybrid speciation.

Interspecific hybridization is an important process through which abrupt speciation can occur. In recent years, genetic changes associated with hybrid speciation have been identified through a variety of techniques, including AFLP/SSR mapping, GISH/FISH and cDNA-AFLP differential display. However, progress in using microarray technology to analyse whole genome/transcriptome changes associated with hybrid speciation has been limited due to the lack of extensive sequence data for many hybrid species and the difficulties in extrapolating results from commercially available microarrays for model species onto nonmodel hybrid taxa. Increasingly therefore researchers studying nonmodel systems are turning to the development of 'anonymous' cDNA microarrays, where the time and cost of producing microarrays is reduced by printing unsequenced cDNA clones, and sequencing only those clones that display interesting expression patterns. Here we describe the creation, testing and preliminary use of anonymous cDNA microarrays to study changes in floral transcriptome associated with allopolyploid speciation in the genus Senecio. We report a comparison of gene expression between the allohexaploid hybrid, Senecio cambrensis, its parental taxa Senecio squalidus (diploid) and Senecio vulgaris (tetraploid), and the intermediate triploid (sterile) hybrid Senecioxbaxteri. Anonymous microarray analysis revealed dramatic differences in floral gene expression between these four taxa and demonstrates the power of this technique for studies of the genetic impact of hybridization in nonmodel flowering plants.

Base Sequence↗
PubMed1990

Determination of Senecio alkaloids by thermospray liquid chromatography/mass spectrometry.

A series of Senecio alkaloid and alkaloid N-oxide standards has been analyzed using positive and negative ion thermospray liquid chromatography/mass spectrometry (LC/MS) with an ammonium acetate-containing mobile phase. On-line separations of pyrrolizidine alkaloids from extracts of Senecio jacobaea (tansy ragwort) and Senecio vulgaris (common groundsel) were done using an ammonium hydroxide-containing mobile phase. All of the alkaloids known to be present in the extracts were detected by ammonium hydroxide thermospray LC/MS, as well as many other components which may be as-yet-unidentified alkaloids.

Acetates↗
PubMed2000

Cloning and expression of homospermidine synthase from Senecio vulgaris: a revision.

Homospermidine synthase. which catalyses the first pathway-specific reaction in pyrrolizidine alkaloid biosynthesis, was cloned from root cultures of Senecio vulgaris and expressed in E. coli. The open reading frame encodes a protein of 370 amino acids with a molecular mass of 40,740 Da. The enzyme is strictly dependent on spermidine as aminobutyl donor since it cannot be substituted by putrescine. The homospermidine synthase from S. vulgaris showed 97.9 and 99.3% nucleic acid identity with two HSS sequences from the closely related species Senecio vernalis. This report also revises data from a previous publication (Kaiser, A., 1999. Cloning and expression of a cDNA encoding homospermidine synthase from Senecio vulgaris (Asteraceae) in Escherichia coli. Plant J. 19. 195 201.) that is incorrect.

Alkyl and Aryl Transferases↗
PubMed1985

Biosynthesis of algal pheromones. A model study with the composite Senecio isatideus.

Several cyclic and alicyclic C11 hydrocarbons have been shown to act as gamete releasing and/or attracting pheromones during sexual reproduction of brown algae (Phaeophyceae). The same compounds are also found in the essential oils of various plants, of which the occurrence of the cycloheptadiene-pheromone ectocarpene in Senecio isatideus (Compositae) is noteworthy. Administration of [3H]dodeca-3,6,9-trienoic acid to cuttings of this plant leads to incorporation of radioactivity into ectocarpene. Double-bond-deuterated nona-3,6-dienoic acid is converted to fucoserratene, the pheromone of several Fucales, which is certainly not present among the hydrocarbons of Senecio. This proves that the pool of medium-chain, multiply unsaturated fatty acids includes precursors of all types of highly unsaturated hydrocarbons. Appropriately labelled (deuterium markers) fatty acid homologues were synthesized and applied to Senecio plantlets to unravel the mechanistic aspects. The results strongly suggest radical initiation of the pheromone biosynthesis by abstraction of a single hydrogen from a 1,4-pentadienyl segment of the fatty acid followed by oxidation to the corresponding cation. This causes fragmentation of the reactive intermediate into an olefine and carbon dioxide by neighbouring-group participation of the flanking double bonds. A tentative biosynthetic scheme is deduced from the experimental results which also sets the stereochemistry of the algal pheromones into a uniform mechanistic concept.

Animals↗
PubMed2006

[General situation of the toxicity researches on Senecio].

This article summarized the toxic components, toxication faeature and mechanism and clinical poisoning reports of Senecio spp. The distribution of major toxic components pyrrolizidine alkaloids (PAs) in Chinese medicinal herbs and the application of Senecio spp. in China were also recapitulated. The proposals for the application and development of Senecio spp. were put forward.

Animals↗
PubMed1991

Toxicity of pyrrolizidine alkaloids from Riddell groundsel (Senecio riddellii) to cattle.

The toxicity of Riddell groundsel (Senecio riddellii) gavaged to calves at a known lethal rate was compared with the toxicity of riddelliine and riddelliine N-oxide, the pyrrolizidine alkaloids isolated from the plant, which were fed by intraruminal infusion. Doses of the alkaloids were adjusted to the amount determined to be in the plant and fed individually and in combination. The relative toxicosis in the calves was measured by clinical signs, serum enzyme changes, survival time to morbidity, and histologic changes. Calves fed Senecio riddellii by gavage for 20 consecutive days to provide 45 mg of total pyrrolizidine alkaloids/kg of body weight/d developed clinical signs and serum enzyme changes typical of seneciosis, with 100% morbidity. However, calves receiving riddelliine at 4.5 mg/kg/d for 20 days had neither serum enzyme changes nor clinical signs of pyrrolizidine alkaloidosis. Calves treated with riddelliine N-oxide (40.5 mg/kg/d), and with riddelliine (4.5 mg/kg/d) and riddelliine N-oxide (40.5 mg/kg/d) in combination, had 100% morbidity, although the latter group had fewer liver lesions. These results establish that the N-oxide form of the alkaloid alone is capable of inducing typical Senecio toxicosis in cattle and that the free base level of the plant cannot be considered to be the sole factor in assessing the toxicity of S riddellii.

Animals↗
PubMed1983

Serum changes and histologic liver lesions due to experimental ingestion of ragwort (Senecio erraticus) in sheep.

Eight 1-year-old Romney-Marsh female sheep were used to test the effect of Senecio erraticus (ragwort). Animals were fed for 60 days on a standard diet incorporating 20% dried ground ragwort. Morphology of the livers was studied by serial biopsy and function by changes in plasma bilirubin concentration, the half-life of bromosulphthalein (BSP), and by the activity of glutamate dehydrogenasa (GD) in plasma during and after Senecio ingestion. All sheep had an increase in bilirubin concentration and GD activity in their plasma and in BSP half-life. These values returned to normal 30 days after ragwort ingestion ceased. Histological studies showed Kupffer cell hypertrophy, fatty degeneration and megalocytosis. These lesions almost disappeared 60 days after stopping Senecio ingestion.

Animals↗
PubMed2005

Molecular characterization of a new begomovirus infecting Senecio scandens in China.

Three begomovirus isolates, G46, G83 and G84 from Senecio scandens showing yellow mosaic symptoms were collected from Guangxi Province, P.R. China. The isolates were detected by PCR using universal primers for begomoviruses. Comparison of partial DNA-A sequences (approximately 500 bp) of the isolates revealed their 98.7-99.1% identity. The isolate G46, chosen for complete DNA-A sequencing, consisted of 2746 nt and had a typical genomic organization of begomoviruses. The G46 DNA-A had the highest sequence identity (72.4%) with that of Ageratum leaf curl virus among begomoviruses. The molecular data suggest that the isolate G46 is a new begomovirus (species), for which the name Senecio yellow mosaic virus (Senecio yellow mosaic virus) is proposed.

Asteraceae↗
PubMed1977

Resistance of the rabbit to dietary pyrrolizidine (Senecio) alkaloid.

Rabbits were fed Senecio jacobaea for 263 days. Total intake of the plant averaged 112.5% of initial body weight. No gross lesions, or changes in serum protein and albumin occurred. Microscopic changes in liver tissue were seen. Two rabbits injected with 150 mg Senecio pyrrolizidine alkaloid/kg body weight died in less than 24 hours. The resistance of the rabbit to chronic Senecio intoxication, but not to injected alkaloid, suggests that alkaloid absorption may be low in this species.

Animals↗
PubMed1983

Carcinogenic activity of Farfugium japonicum and Senecio cannabifolius.

The carcinogenicity of Farfugium japonicum and Senecio cannabifolius was studied in ACI rats. In Group I, rats were given a diet containing 20% Farfugium japonicum. Groups II, III, IV and V were given diets containing 8%, 4%, 1% and 0.2% Senecio cannabifolius until the end of the experiment, respectively. The experiment was terminated after 480 days, except for Group V which was terminated 560 days after the start of feeding. Hemangioendothelial sarcoma of the liver and liver cell adenoma were induced in Groups I, IV and V. All rats in Groups II and III died of hepatotoxicity within a short period.

Adenoma↗
PubMed1981

Effect of consumption of milk from goats fed Senecio jacobaea on hepatic drug metabolizing enzyme activities in rats.

Milk from lactating goats fed tansy ragwort (Senecio jacobaea) was evaluated for its ability to influence hepatic drug metabolism. The milk after being freeze-dried was fed to male rats for 1 week ad lib. A significant reduction in the activities of hepatic aminopyrine N-demethylase and aryl hydrocarbon hydroxylase was obtained. There was no significant change in the activities of microsomal epoxide hydrolase and cytosolic glutathione S-transferase. The data suggest that consumption of milk from goats fed Senecio jacobaea produces a selective alteration of the activities of hepatic drug-metabolizing enzymes.

Animals↗
PubMed1999

Cloning and expression of a cDNA encoding homospermidine synthase from Senecio vulgaris (Asteraceae) in Escherichia coli.

The enzyme homospermidine synthase catalyzes the NAD+-dependent conversion of 2 mol putrescine into homospermidine. Instead of putrescine, spermidine can substitute for the first putrescine moiety in plants, in which case diaminopropane instead of ammonia is released. The enzyme facilitates the formation of the 'uncommon' polyamine homospermidine which is an important precursor in the biosynthesis of pyrrolizidine alkaloids. The first plant homospermidine synthase was purified to apparent chemical homogenity from the root tissue culture Senecio vernalis (Asteraceae) (Böttcher et al. 1994, Can. J. Chem. 72, 80-85; Ober 1997, Dissertation). Four endopeptidase LysC fragments were sequenced from the purified protein. With the aid of degenerate primers against these peptides, a cDNA encoding homospermidine synthase was now cloned and characterized from Senecio vulgaris. The nucleotide sequence of the cloned cDNA revealed an open reading frame of 1155-base pairs containing 385 amino acids with a predicted Mr of 44500. GenBank research revealed that the deduced amino acid sequence shows 59% identity to human deoxyhypusine synthase. The homospermidine synthase encoding cDNA was subcloned into the expression vector pet15b and overexpressed in E. coli. The recombinant enzyme formed upon expression catalyzed homospermidine synthesis.

Alkyl and Aryl Transferases↗
PubMedDate not supplied

The genetic basis of floral variation in Senecio jacobaea (Asteraceae).

The self-incompatible composite Senecio jacobaea (ragwort) exhibits geographic variation in the frequency of rayed and discoid (rayless) individuals. Hybrid progenies from within- and between-morph crosses were established in a seminatural (garden) environment to determine whether patterns of segregation conform to single-gene predictions (as found in other Senecio species), whether the direction of dominance is conducive to rapid evolutionary change in ray morphology, and whether geographically distant populations of the discoid morph utilize the same or different genes to suppress ray development. Data from segregating F2 and BC families were consistent with a genetic model involving one major locus and an unknown number of modifiers. Analysis of F1 progenies from different intermorph crosses using the same rayed plant as a seed parent revealed a variable and incomplete pattern of dominance, with a trend toward partial dominance in some crosses. Hybridizations between discoid populations produced a few rayed progeny (4%), but there was no tendency for the frequency of rayed progeny to increase with the geographic distance separating the parent populations. Results of this study indicate that major mutations have been important for the evolution of discoid populations of ragwort, that ray-suppressing mutations should be directly available to selection in most populations, and that the suppression of rays is conditioned by the same or similar gene(s) in Atlantic and Baltic populations of the discoid taxon.

Adaptation, Biological↗