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At least 865 records · Page 48Linked to original sources
PubMed1983

Homer's moly identified as Galanthus nivalis L.: physiologic antidote to stramonium poisoning.

The antidotal properties of certain naturally occurring medicinal plants against central nervous system intoxication appear to have been empirically established in ancient times. Homer, in his epic poem, the Odyssey, described a plant, "moly," used by Odysseus as an antidote against Circe's poisonous drugs. Centrally acting anticholinergic agents are thought to have been used by Circe to induce amnesia and a delusional state in Odysseus' crew. We present evidence to support the hypothesis that "moly" might have been the snowdrop, Galanthus nivalis, which contains galanthamine, a centrally acting anticholinesterase. Thus the description of "moly" as an antidote in Homer's Odyssey may represent the oldest recorded use of an anticholinesterase to reverse central anticholinergic intoxication.

Antidotes↗
PubMed1996

Ingestion of angel's trumpet: an increasingly common source of toxicity.

Angel's trumpet is a hallucinogenic plant commonly cultivated as an ornamental in the southeastern United States. Consumption of any part of the plant may result in severe anticholinergic toxicity. In past years, toxicity has largely resulted from accidental ingestion, but in 1994 there was a ten-fold increase in the number of reported ingestions throughout the state of Florida, largely by persons experimenting with the plant for its hallucinogenic effects. We report three such cases and review the literature on diagnosis, treatment, and sequelae of angel's trumpet intoxication.

Adolescent↗
PubMed2006

Host tolerance does not impose selection on natural enemies.

Coevolution between hosts and their natural enemies is believed to operate through the evolution of resistance traits. Although the importance of tolerance to natural enemies as an alternative defensive strategy has been recognized, there is still no consensus about the possible role of host tolerance in the evolutionary outcome of the interaction. Here, using bioassay experiments, we tested the hypothesis that variation in host tolerance among selected plant genotypes could impose a selection pressure upon a specialist herbivore. Tolerance did not affect herbivore larvae survival, weight gain, efficiency of food consumption, total food consumption, developmental time and adult mass. These results therefore do not support the hypothesis that host tolerance could affect natural enemy performance. However, resistance did negatively affect herbivore larva survival. Genetic variation in herbivore larva survival was detected, thus suggesting the potential for a coevolutionary response. Our results indicate that host tolerance would reduce opportunities for a coevolutionary response by the natural enemies of the host. Contrary to predictions from previous models, our results suggest that host tolerance may constitute an evolutionarily unstable defensive strategy.

Animals↗
PubMed1996

The case of hallucinogenic plants and the Internet.

The advent of the Internet both created opportunities and provoked problems for students, teachers, and parents. This article uses the example of Internet access to explicit information about locally available hallucinogenic plants to focus on important new issues in education: determining validity of Internet information and cultivating critical Internet consumer skills in students. Basic "textbook" information on three common psychotropic plants is contrasted with pro-drug information from selected World Wide Web sites. Guidelines are offered for evaluating Internet information, and suggestions are offered for developing effective decision-making skills in students.

Adolescent↗
PubMed1996

VirB2 is a processed pilin-like protein encoded by the Agrobacterium tumefaciens Ti plasmid.

The mechanism of DNA transmission between distinct organisms has remained a subject of long-standing interest. Agrobacterium tumefaciens mediates the transfer of plant oncogenes in the form of a 25-kb T-DNA sector of a resident Ti plasmid. A growing body of evidence leading to the elucidation of the mechanism involved in T-DNA transfer comes from studies on the vir genes contained in six major operons that are required for the T-DNA transfer process. Recent comparative amino acid sequence studies of the products of these vir genes have revealed interesting similarities between Tra proteins of Escherichia coli F factor, which are involved in the biosynthesis and assembly of a conjugative pilus, and VirB proteins encoded by genes of the virB operon of A. tumefaciens pTiC58. We have previously identified VirB2 as a pilin-like protein with processing features similar to those of TraA of the F plasmid and have shown that VirB2 is required for the biosynthesis of pilin on a flagella-free Agrobacterium strain. In the present work, VirB2 is found to be processed and localized primarily to the cytoplasmic membrane in E. coli. Cleavage of VirB2 was predicted previously to occur between alanine and glutamine in the sequence -Pro-Ala-Ala-Ala-Glu-Ser-. This peptidase cleavage sequence was mutated by an amino acid substitution for one of the alanine residues (D for A at position 45 [A45D]), by deletion of the three adjacent alanines, and by a frameshift mutation 22 bp upstream of the predicted Ala-Glu cleavage site. With the exception of the frameshift mutation, the alanine mutations do not prevent VirB2 processing in E. coli, while in A. tumefaciens they result in VirB2 instability, since no holo- or processed protein is detectable. All of the above mutations abolish virulence. The frameshift mutation abolishes processing in both organisms. These results indicate that VirB2 is processed into a 7.2-kDa structural protein. The cleavage site in E. coli appears to differ from that predicted in A. tumefaciens. Yet, the cleavage sites are relatively close to each other since the final cleavage products are similar in size and are produced irrespective of the length of the amino-terminal portion of the holoprotein. As we observed previously, the similarity between the processing of VirB2 in A. tumefaciens and the processing of the propilin TraA of the F plasmid now extends to E. coli.

Agrobacterium tumefaciens↗
PubMed2002

Biogenesis of T pili in Agrobacterium tumefaciens requires precise VirB2 propilin cleavage and cyclization.

VirB2 propilin is processed by the removal of a 47-amino-acid signal peptide to generate a 74-amino-acid peptide product in both Escherichia coli and Agrobacterium tumefaciens. The cleaved VirB2 protein is further cyclized to form the T pilin in A. tumefaciens but not in E. coli. Mutations in the signal peptidase cleavage sequence of VirB2 propilin cause the formation of aberrant T pilin and also severely attenuate virulence. No T pilus was observed in these mutants. The potential role of the exact VirB2 propilin cleavage and cyclization in T pilus biogenesis and virulence is discussed.

Agrobacterium tumefaciens↗