- Electrophysiological responses of bactrocera kraussi (Hardy) (tephritidae) to rectal gland secretions and headspace volatiles emitted by conspecific males and females
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Pheromones are biologically important in fruit fly mating systems, and also have potential applications as attractants or mating disrupters for pest management. Bactrocera kraussi (Hardy) (Diptera: Tephritidae) is a polyphagous pest fruit fly for which the chemical profile of rectal glands is available for males but not for females. There have been no studies of the volatile emissions of either sex or of electrophysiological responses to these compounds. The present study (i) establishes the chemical profiles of rectal gland contents and volatiles emitted by both sexes of B. kraussi by gas chromatography–mass spectrometry (GC–MS) and (ii) evaluates the detection of the identified compounds by gas chromatography–electroantennogram detection (GC–EAD) and –electropalpogram detection (GC–EPD). Sixteen compounds are identified in the rectal glands of male B. kraussi and 29 compounds are identified in the rectal glands of females. Of these compounds, 5 were detected in the headspace of males and 13 were detected in the headspace of females. GC–EPD assays recorded strong signals in both sexes against (E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, 2-ethyl-7-mehtyl-1,6-dioxaspiro[4.5]decane isomer 2, (E,Z)/(Z,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, and (Z,Z)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane. Male antennae responded to (E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, 2-methyl-6-pentyl-3,4-dihydro-2H-pyran, 6-hexyl-2-methyl-3,4-dihydro-2H-pyran, 6-oxononan-1-ol, ethyl dodecanoate, ethyl tetradecanoate and ethyl (Z)-hexadec-9-enoate, whereas female antennae responded to (E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane and 2-methyl-6-pentyl-3,4-dihydro-2H-pyran only. These compounds are candidates as pheromones mediating sexual interactions in B. kraussi.
- Holgate, Danielle,Jamie, Ian M.,Jamie, Joanne F.,Mendez, Vivian,Noushini, Sally,Park, Soo Jean,Perez, Jeanneth,Taylor, Phillip W.
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- Attraction and electrophysiological response to identified rectal gland volatiles in bactrocera frauenfeldi (schiner)
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Bactrocera frauenfeldi (Schiner) (Diptera: Tephritidae) is a polyphagous fruit fly pest species that is endemic to Papua New Guinea and has become established in several Pacific Islands and Australia. Despite its economic importance for many crops and the key role of chemical-mediated sexual communication in the reproductive biology of tephritid fruit flies, as well as the potential application of pheromones as attractants, there have been no studies investigating the identity or activity of rectal gland secretions or emission profiles of this species. The present study (1) identifies the chemical profile of volatile compounds produced in rectal glands and released by B. frauenfeldi, (2) investigates which of the volatile compounds elicit an electroantennographic or electropalpographic response, and (3) investigates the potential function of glandular emissions as mate-attracting sex pheromones. Rectal gland extracts and headspace collections from sexually mature males and females of B. frauenfeldi were analysed by gas chromatography-mass spectrometry. Male rectal glands contained (E,E)-2-ethyl-8-methyl-1,7-dioxaspiro [5.5]undecane as a major component and (E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane as a moderate component. Minor components included palmitoleic acid, palmitic acid, and ethyl oleate. In contrast, female rectal glands contained (E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane and ethyl laurate as major components, ethyl myristate and ethyl palmitoleate as moderate components, and 18 minor compounds including amides, esters, and spiroacetals. Although fewer compounds were detected from the headspace collections of both males and females than from the gland extractions, most of the abundant chemicals in the rectal gland extracts were also detected in the headspace collections. Gas chromatography coupled electroantennographic detection found responses to (E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane from the antennae of both male and female B. frauenfeldi. Responses to (E,E)-2-ethyl-8-methyl-1,7-dioxaspiro[5.5]undecane were elicited from the antennae of females but not males. The two spiroacetals also elicited electropalpographic responses from both male and female B. frauenfeldi. Ethyl caprate and methyl laurate, found in female rectal glands, elicited responses in female antennae and palps, respectively. Y-maze bioassays showed that females were attracted to the volatiles from male rectal glands but males were not. Neither males nor females were attracted to the volatiles from female rectal glands. Our findings suggest (E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane and (E,E)-2-ethyl-8-methyl-1,7-dioxaspiro[5.5]undecane as components of a sex-attracting pheromone in B. frauenfeldi.
- Alvarez, Vivian Mendez,Holgate, Danielle,Jamie, Ian,Jamie, Joanne,Jean Park, Soo,Noushini, Saeedeh,Perez, Jeanneth,Taylor, Phillip
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supporting information
(2020/03/23)
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- Identification and synthesis of new sex-specific components of olive fruit fly (Bactrocera oleae) female rectal gland, through original Negishi reactions on supported catalysts
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In the present study, eleven new sex-specific components extracted from female rectal gland of olive fruit flies were synthesized and identified. The quantitative determination of those components by GC and GC/EI-MS, at different moments of the insect life span, highlighted the growing trend of their secretion. While for the synthesis of saturated esters, conventional transesterification methods could be adopted, for the synthesis of unsaturated components, a Negishi cross-coupling between organozinc halides and (Z)-1-bromo-1-alkenes was developed. To the extent of our knowledge, this reaction represents the first example of supported-catalyst promoted Negishi coupling, between an alkylzinc reagent and an alkenyl halide.
- Fusini, Graziano,Barsanti, Davide,Angelici, Gaetano,Casotti, Gianluca,Canale, Angelo,Benelli, Giovanni,Lucchi, Andrea,Carpita, Adriano
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p. 4381 - 4389
(2018/07/21)
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- Synthesis and Characterization of Novel Acyl-Glycine Inhibitors of GlyT2
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It has been demonstrated previously that the endogenous compound N-arachidonyl-glycine inhibits the glycine transporter GlyT2, stimulates glycinergic neurotransmission, and provides analgesia in animal models of neuropathic and inflammatory pain. However, it is a relatively weak inhibitor with an IC50 of 9 μM and is subject to oxidation via cyclooxygenase, limiting its therapeutic value. In this paper we describe the synthesis and testing of a novel series of monounsaturated C18 and C16 acyl-glycine molecules as inhibitors of the glycine transporter GlyT2. We demonstrate that they are up to 28 fold more potent that N-arachidonyl-glycine with no activity at the closely related GlyT1 transporter at concentrations up to 30 μM. This novel class of compounds show considerable promise as a first generation of GlyT2 transport inhibitors.
- Mostyn, Shannon N.,Carland, Jane E.,Shimmon, Susan,Ryan, Renae M.,Rawling, Tristan,Vandenberg, Robert J.
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p. 1949 - 1959
(2017/09/26)
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