Inhibitors of Sensillar Esterase Block Reversibly the Responses of Moth Pheromone Receptor Cells

Pophof, B.

doi:10.1111/j.1749-6632.1998.tb10589.x

Cited by 7 publications

(11 citation statements)

References 6 publications

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“…The initial slope, whether determined by a straight line fit (not shown) or computed from t1/2 rise and half the SP amplitude, exhibited a clear dose dependence in correlation with the SP amplitude (Figs·7B, 9B). In contrast to studies with pheromone sensilla of A. polyphemus and Antheraea pernyi (Zack, 1979;Kaissling et al, 1987;Kodadová, 1993;Kodadová and Kaissling, 1996;Pophof, 1998) and benzoic acid-sensitive sensilla of Bombyx mori (Kodadová, 1993), in our experiments with short pheromone stimuli, t1/2 rise showed virtually no dose dependence and was not influenced by adaptation (Fig.·7C). The major difference in the regimens of stimulation between our study and the studies mentioned above is the stimulus duration (50·ms versus 2·s or 5·s).…”

Section: Discussioncontrasting

confidence: 46%

Adaptation in pheromone-sensitive trichoid sensilla of the hawkmoth Manduca sexta

Dolzer

Fischer

Stengl

2003

Journal of Experimental Biology

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While the transduction cascade of pheromone-sensitive olfactory receptor neurons (ORNs) in insects has been thoroughly investigated in vitro (Breer et al., 1988Boekhoff et al., 1990Boekhoff et al., , 1993Stengl et al., 1992;Stengl, 1993Stengl, , 1994Wegener et al., 1993Wegener et al., , 1997, little is known about olfactory adaptation and the mechanisms involved. Adaptation is a universal characteristic of receptor cells of all sensory modalities (Burkhardt, 1961). There are different definitions for the term 'adaptation' but implicit in any definition is a decrease in sensitivity due to the influence of a previous (conditioning) stimulus (Zack, 1979).Moths distinguish pheromone mixtures according to the concentration ratios of the different pheromone components. Thus, differentiation of pheromone concentrations is very crucial for recognition of prospective mates. Turbulences and wind velocities determine the structure of the pheromone filaments that stimulate the antenna of a flying moth. Thus, adapting and non-adapting pheromone stimuli of variable concentrations and stimulus durations reach different parts of the antenna at various time intervals. It is still unknown how the moth can recognize relevant pheromone ratios in various states of adaptation. In our study of pheromone-sensitive ORNs, we examine how adapting pheromone stimuli affect the encoding of different pheromone concentrations (quantity coding) in the intact moth. We distinguish the rapidly (within seconds to minutes) reversible reduction of sensitivity due to prior stimulation (short-term adaptation) from the decline in excitation, as seen during a phasic-tonic response to a stimulus of long duration (desensitization; Zufall and Leinders-Zufall, 2000). Thus, we compare quantity coding in response to short (50·ms) and long (1000·ms) pheromone stimuli, as possibly encountered during flight to the calling female. We do not examine the more slowly occurring (within several minutes to hours) reduction of sensitivity due to In extracellular tip recordings from long trichoid sensilla of male Manduca sexta moths, we studied dose-response relationships in response to bombykal stimuli of two different durations in the adapted and the non-adapted state. Bombykal-responsive cells could be distinguished from non-bombykal-sensitive cells in each trichoid sensillum because the bombykal-responsive cell always generated the action potentials of larger initial amplitude. The bombykal cell, which was recorded at a defined location within a distal flagellar annulus, can resolve at least four log 10-units of pheromone concentrations but is apparently unable to encode all stimulus durations tested. Parameters of the amplitudemodulated sensillar potential and the frequencymodulated action potential responses were examined in different states of adaptation. Evidence is presented for the existence of several mechanisms of adaptation, which affect distinct steps of the transduction cascade. After adapting pheromone stimuli, the sensillar potential rises to a lower ampl...

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Section: Discussioncontrasting

confidence: 46%

Adaptation in pheromone-sensitive trichoid sensilla of the hawkmoth Manduca sexta

Dolzer

Fischer

Stengl

2003

Journal of Experimental Biology

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“…Intensity and kinetic parameters of the EAG responses of male antennae to Z11‐16:Ac were altered in the presence of Z11‐16:TFMK, indicating that the fluorinated analogue interacts with pheromone reception at the sensory organ level. A similar type of effect was reported to occur with the well‐known esterase inhibitor 3‐octylthio‐trifluoropropan‐2‐one (OTFP) in M brassicae 7 and in Antheraea polyphemus 6. In other moth species, biochemical studies indicate that several steps of olfactory reception are affected by TFMKs.…”

Section: Discussionsupporting

confidence: 60%

“…Among other candidates, and due to the presence in the insect antenna of esterases specifically involved in the catabolism of pheromone compounds, a class of esterase inhibitors, the trifluoromethyl ketones,2–5 has been the subject of great interest. Specific applications of the latter substances to the inhibition of the insect olfaction process have been reported 6. 7 Thus, pheromone analogues bearing a trifluoromethyl ketone function have been synthesized8, 9 and their biological activity evaluated 9–11.…”

Section: Introductionmentioning

confidence: 99%

Disruption of responses to pheromone by (Z)‐11‐hexadecenyl trifluoromethyl ketone, an analogue of the pheromone, in the cabbage armyworm Mamestra brassicae

Renou

Berthier

Guerrero

2002

Pest Management Science

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The effects of (Z)-11-hexadecenyl trifluoromethyl ketone (Z11-16:TFMK) a fluorinated pheromone analogue, on the responses to sex pheromone of the male cabbage armyworm, Mamestra brassicae, have been investigated in an actograph and by electroantennography (EAG). In spite of its structural proximity with the natural pheromone, Z11-16:TFMK was poorly active in EAG, and not active on male behaviour. When permeated in the air, Z11-16:TFMK reversibly inhibited the electroantennographic responses to (Z)-11-hexadecenyl acetate (Z11-16:Ac), the main component of the sex pheromone. In the actograph, the latency of the activation was increased and the intensity of the behavioural activity of males in response to Z11-16:Ac was significantly reduced in the presence of Z11-16:TFMK. These results, along with others previously reported by us, provide new pointers to the possible use of Z11-16:TFMK in pest-control strategies.

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“…TFKs were first reported as inhibitors of acetylcholine esterase (19), and shortly thereafter as inhibitors of both general esterase activity and JHE activity (19)(20)(21)(22). Subsequently, they have been investigated as inhibitors of other esterases including mammalian esterases (23) and insect pheromone degrading esterases (24)(25)(26). They have proven to be very useful compounds for studying insect development (7).…”

Section: Introductionmentioning

confidence: 99%

Structural Studies of a Potent Insect Maturation Inhibitor Bound to the Juvenile Hormone Esterase ofManduca sexta^,

et al. 2006

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Juvenile hormone (JH) is an insect hormone containing an α,β unsaturated ester consisting of a small alcohol and long, hydrophobic acid. JH degradation is required for proper insect development. One pathway of this degradation is through juvenile hormone esterase (JHE), which cleaves the JH ester bond to produce methanol and JH acid. JHE is a member of the functionally divergent α/β-hydrolase family of enzymes, and is a highly efficient enzyme that cleaves JH at very low in vivo concentrations. We present here a 2.7 Å crystal structure of JHE from the tobacco hornworm Manduca sexta (MsJHE) in complex with the transition state analog inhibitor 3-octylthio-1,1,1-trifluoropropan-2-one (OTFP) covalently bound to the active site. This crystal structure, the first JHE structure reported, contains a long, hydrophobic binding pocket with the solvent inaccessible catalytic triad located at the end. The structure explains many of the interactions observed between JHE and its substrates and inhibitors, such as the preference for small alcohol groups and long hydrophobic backbones. The most potent JHE inhibitors identified to date contain a trifluoromethyl ketone (TFK) moiety and have a sulfur atom beta to the ketone. In this study, sulfur-aromatic interactions were observed between the sulfur atom of OTFP and a conserved aromatic residue in the crystal structure. Mutational analysis supported the hypothesis that these interactions contribute to the potency of sulfur-containing TFK inhibitors. Together these results clarify the binding mechanism of JHE inhibitors and provide useful observations for the development of additional enzyme inhibitors for a variety of enzymes. NIH Public Access Author ManuscriptBiochemistry. Author manuscript; available in PMC 2014 December 23. Figure 1A) is a sesquiterpenoid insect hormone that controls a wide range of biological processes. JH and/or its metabolites are known to have effects on insect life cycle processes such as development, metamorphosis, reproduction, diapause, migration, polyphenism and metabolism (1, 2). Perturbation of this system can have deleterious consequences for the insect, a fact which has been exploited for pest control. For example, the JH analog methoprene is a significant chemical line of defense against the larvae of mosquitoes that carry West Nile Virus (3). JH can be metabolized through cleavage of either its epoxide or ester moiety. The relative importance of these two pathways, both catalyzed by α/β-hydrolase enzymes (4-6), varies with insect species, development stage and tissue. Normal lepidopteran metamorphosis, for example, requires the degradation of JH via ester hydrolysis. Inhibition of ester hydrolysis leads to abnormally large larvae and delayed pupation (7). The enzyme responsible for this ester hydrolysis is juvenile hormone esterase (JHE), which is found in the hemolymph and other tissues of insects at key times in development.Insects have significant effects on human health, as vectors for diseases such as malaria and virus induced en...

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Inhibitors of Sensillar Esterase Block Reversibly the Responses of Moth Pheromone Receptor Cells

Cited by 7 publications

References 6 publications

Adaptation in pheromone-sensitive trichoid sensilla of the hawkmoth Manduca sexta

Adaptation in pheromone-sensitive trichoid sensilla of the hawkmoth Manduca sexta

Disruption of responses to pheromone by (Z)‐11‐hexadecenyl trifluoromethyl ketone, an analogue of the pheromone, in the cabbage armyworm Mamestra brassicae

Structural Studies of a Potent Insect Maturation Inhibitor Bound to the Juvenile Hormone Esterase ofManduca sexta^,

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Inhibitors of Sensillar Esterase Block Reversibly the Responses of Moth Pheromone Receptor Cells

Cited by 7 publications

References 6 publications

Adaptation in pheromone-sensitive trichoid sensilla of the hawkmoth Manduca sexta

Adaptation in pheromone-sensitive trichoid sensilla of the hawkmoth Manduca sexta

Disruption of responses to pheromone by (Z)‐11‐hexadecenyl trifluoromethyl ketone, an analogue of the pheromone, in the cabbage armyworm Mamestra brassicae

Structural Studies of a Potent Insect Maturation Inhibitor Bound to the Juvenile Hormone Esterase ofManduca sexta,

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Structural Studies of a Potent Insect Maturation Inhibitor Bound to the Juvenile Hormone Esterase ofManduca sexta^,