Excretion of miserotoxin and detoxification of the aglycone by grasshoppers (Orthoptera: Acrididae).

Two species of grasshoppers (Melanoplus bivittatus and M. sanguinipes) tolerated high levels of miserotoxin (3-nitro-1-propyl-beta-D-glucopyranoside) in their diet. Miserotoxin is a causative agent in cattle poisoning when timber milkvetch (Astragalus miser) is consumed. Toxic effects were averted by grasshoppers in part by excretion of the intact glycoside. When the aglycone was administered, detoxification was achieved by two routes: by oxidation of the aglycone to 3-nitropropionic acid which was then conjugated with glycine, and by glucosylation of the aglycone to miserotoxin, in each case followed by excretion.

Structure revision of isoline (ruwenine), bisline and isolinecic acid.

X-ray crystallography of bisline, and the chemical interconversion of bisline and isoline (ruwenine), revealed that the structures previously assigned to these alkaloids required revision; as did that of isolinecic acid.

The glycosidic precursor of (Z)-5-ethylidene-2(5H)-furanone in Halocarpus biformis juvenile foliage.

A new glycosidic lactone, (5R,6R)-5-(1-hydroxyethyl)-2(5H)-furanone beta-D-glucopyranoside, has been identified as the principal precursor of (Z)-5-ethylidene-2(5H)-furanone in juvenile foliage of the New Zealand tree Halocarpus biformis. Three related lactone glycosides were isolated in smaller amounts, together with the known phenolic glycosides pyroside, arbutin and picein. The principal lactone glycoside underwent facile elimination of glucose, in neutral or basic conditions, to yield (Z)-5-ethylidene-2(5H)-furanone and its E-isomer. This lactone glycoside was also detected in foliage of H. bidwillii and H. kirkii.

In-vitro biotransformation of 3-nitropropanol (miserotoxin aglycone) by horse liver alcohol dehydrogenase.

The oxidation of 3-nitropropanol (NPOH) by equine alcohol dehydrogenase (ADH) was examined by HPLC. The intermediate product, 3-nitropropanal (NPAL), was synthesized and it was also trapped in the reaction mixture as the semicarbazone. At neutral pH, NPAL spontaneously decomposed to nitrite and acrolein but in the presence of ADH, NPAL was partially oxidized to 3-nitropropionic acid (NPA). HPLC conditions are described which simultaneously resolve the components of the reaction mixtures. However, the results from previous studies suggest an efficient conversion of NPOH to NPA in vivo without the spontaneous formation of acrolein.

Female-produced sexual pheromone ofSceliodes cordalis (Lepidoptera: Pyralidae).

(E)-11-Hexadecen-1-yl acetate and (E)-11-hexadecen-1-ol were identified in extracts from the abdominal pheromone gland of femaleSceliodes cordalis and in a 1∶1 ratio acted as a potent field attractant for males. Sustained upwind flight by males to this mixture in a wind tunnel confirmed the identity of these compounds as major components of the natural sex pheromone of this species. The synthetic pheromone was used to define the annual limits of male flight activity. In the presence of 1-10 µg of pheromone per liter of air, the mating rate of laboratory populations was halved. TheZ isomers of both pheromone components decreased the numbers of males captured in traps baited with virgin females in the field and inhibited upwind flight in the wind tunnel. The attraction of males ofMnesictena flavidalis to virgin females ofS. cordalis and synthetic mixtures was demonstrated to be due to the acetate component alone. MaleEudonia sp. nrlinealis were captured by (Z)-11-hexadecen-1-yl acetate.

Ultrastructure of exocrine prothoracic gland ofDatana ministra (Drury) (Lepidoptera: Notodontidae) and the nature of its secretion.

Datana ministra larvae possess a gland situated in the ventral anterior portion of the prothorax. The gland consists of a single sac and is only charged with secretion in the last instar. Its orifice, a simple slit, opens into a transverse invagination of the integument in the cervical margin of the prosternite. The components of the gland have been identified by GC and GCMS and have been shown to be dodecanol, dodecyl acetate, and dodecyl formate. The morphology of the gland and the chemistry of the secretion are discussed in relation to other notodontid larvae which have been investigated. It is conjectured that the secretion is not defensive in nature but may function as a dispersal pheromone.

Metabolism and distribution of 3,4-epithiobutanenitrile in the rat.

The metabolism and distribution of [2-14C]- and 35S-labelled 3,4-epithiobutanenitrile (4ETN), a thiirane occurring naturally in cruciferous vegetables, was studied in the rat. A dose of c. 11 mg 4ETN/kg body weight was rapidly transformed into water-soluble compounds and was mainly excreted in the urine, irrespective of the route of administration (oral or ip). The main metabolite in the urine was identified by gas chromatography-mass spectrometry as a mercapturic acid derivative. Low residual radioactivity demonstrated in organs 72 hr after administration was consistent with an earlier report that the thiirane may function as a weak biological alkylating agent.

Measurement of release rates of gossyplure from controlled release formulations by mini-airflow method.

The use of the mini-airflow apparatus for the measurement of gossyplure release rates is described. The method involves the passage of air over controlled-release dispensers containing radiolabeled pheromone, through a coarse frit, and entrapment of the gossyplure on glass beads. Desorption of the beads with solvent is followed by quantification by liquid scintillation counting. The results of release rate measurements from hollow fibers, red rubber septa, and red rubber wicks are discussed.

Clinical signs and studies of the site of action of purified larkspur alkaloid, methyllycaconitine, administered parenterally to calves.

The purified diterpenoid alkaloid, methyllycaconitine was isolated from Delphinium brownii and injected intravenously into beef calves in order to observe the clinical signs. Following injection and depending upon dosage, calves showed a variety of signs; agitation, respiratory difficulty and loss of muscle control. Collapse occurred at higher doses of methyllycaconitine. Onset of clinical signs after injection occurred within two to three minutes, and recovery was rapid, clinical signs disappearing within five to ten minutes postinjection.The clinical signs observed are consistent with a skeletal neuromuscular site of action. Methyllycaconitine may have a curare-like action of postsynaptic blockage of nicotinic cholinergic receptors in cattle as has been demonstrated by in vitro experiments in other species. Physostigmine appears to be an effective antidote to methyllycaconitine.

The principal toxin of Delphinium brownii Rydb., and its mode of action.

Examination of D. brownii, a stock-poison of Western Canada, revealed that the principal toxin was methyllycaconitine: a potent neuromuscular blocking agent which appears to act competitively at nicotinic receptors.