Chemical Composition of the Rectal Gland and Volatiles Released by Female Queensland Fruit Fly, Bactrocera tryoni (Diptera: Tephritidae).

The composition of the rectal gland secretion and volatiles emitted by female Queensland fruit fly, Bactrocera tryoni was investigated. Esters were found to be the main compounds in the gland extracts and headspace, while amides were the minor compounds in the gland extracts and headspace. Ethyl dodecanoate, ethyl tetradecanoate, ethyl (Z9)-hexadecenoate and ethyl palmitate were the main esters in the gland extracts, while ethyl dodecanoate and ethyl tetradecanoate were the main esters in the headspace. Four amides (N-(3-methylbutyl)acetamide), N-(2-methylbutyl)propanamide, N-(3-methylbutyl)propanamide, and N-(3-methylbutyl)-2-methylpropanamide were found in the gland extracts and the headspace. Among the amides, N-(3-methylbutyl)acetamide and N-(3-methylbutyl)propanamide were the main amides in the gland extracts and the headspace. Traces of three spiroacetals were found both in the gland extracts and in the headspace. (E,E)-2,8-Dimethyl-1,7-dioxaspiro[5.5]undecane, (E,E)-2-ethyl-8-methyl-1,7-dioxaspiro[5.5]undecane, (E,E)-2-propyl-8-methyl-1,7-dioxaspiro[5.5]undecane. All compounds found in the headspace were present in the extract of the rectal gland suggesting that the rectal gland is the main source of the headspace volatiles, whose function remains to be elucidated. This is the first comprehensive chemical analysis of the rectal gland secretions and volatiles of female B. tryoni, and further laboratory and field bioassays are required to determine the function of compounds identified in this study. Discovery of the same amides previously identified in the male rectal gland in the female rectal gland raises questions about the pheromonal role previously suggested for these compounds.

Preparation of secolycorines against acetylcholinesterase.

5,6-Secolycorines possessing a 5,6-dihydrophenanthridine skeleton were facilely prepared from lycorine through chemical transformations, mainly including N-alkylation, Hofmann degradation type reaction, reductive cleavage of trichloroethylcarbonyl moiety, and hydrogenation. Several secolycorine derivatives showed potent inhibitory activity against acetylcholinesterase with the IC(50) value at micromolar range and are more potent than galanthamine.

New sesquiterpenic phytotoxins establish unprecedented relationship between different groups of blackleg fungal isolates.

A comprehensive search for sesquiterpenic metabolites produced by isolates of the blackleg fungus [Leptosphaeria maculans (Desm.)] Ces. et de Not. [asexual stage Phoma lingam (Tode ex Fr.) Desm.] revealed that an isolate pathogenic on both canola and brown mustard (IBCN 18) and two isolates pathogenic on brown mustard (Laird 2 and Mayfair 2) produced similar sesquiterpenes. The isolation, chemical structure elucidation, and phytotoxicity of these new sesquiterpenes with silphinene and selinene type skeletons is reported. This is the first time that an isolate virulent on canola and brown mustard is found to produce metabolites characteristic of both virulent (sirodesmins) and avirulent (phomalairdenones) L. maculans/P. lingam. In the context of grouping the various isolates of L. maculans/P. lingam, this work suggests an additional pathogenicity group comprising isolates that produce both sirodesmins and phomalairdenones and are virulent on both canola and brown mustard.