The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Walter S Leal - One of the best experts on this subject based on the ideXlab platform.
-
Reducing responses by adding rigidity to the C1–C9 moiety.
2013Co-Authors: Antony M. Hooper, John A. Pickett, Walter S LealAbstract:(A) Current responses elicited by (10E,12Z)-hexadecadien-4-yn-1-ol (10), (4Z,10E,12Z)-hexadecatrien-1-ol (11), and Bombykol (1) from BmorOR1•BmorOrco-expressing oocytes (ligands presented at 10 µM). EC50s 1.7×10−5M, 1.3×10−5M, and 5.9×10−6M, respectively. (B) Dose-dependent relationships, n = 3–4.
-
Chemical structures.
2013Co-Authors: Antony M. Hooper, John A. Pickett, Walter S LealAbstract:Structures of the silkworm moth sex pheromone (1) and Bombykol-related compounds, which were used to challenge BmorOR1•BmorOrco-expressing oocytes.
-
Chemical analysis of synthetic pheromone components.
2013Co-Authors: Antony M. Hooper, John A. Pickett, Walter S LealAbstract:GC-MS traces obtained from Bombykol (upper trace) and bombykal (lower trace) samples freshly prepared to challenge BmorOR1•BmorOrco-expressing oocytes. Arrow indicates trace amounts of bombykal (1.3%) in the Bombykol sample, whereas a dotted arrow shows traces of Bombykol (0.9%) in bombykal sample. The ratio of Bombykol (retention time, 16.06 min) to bombykal (15.42 min) in the two samples was 1.015±0.02, n = 3.
-
Effect of number of carbons distal to unsaturation.
2013Co-Authors: Antony M. Hooper, John A. Pickett, Walter S LealAbstract:(A) Current responses obtained by challenging BmorOR1•BmorOrco-expressing oocytes with Bombykol (lower trace, positive control), (10E,12Z)-octadecadien-1-ol (7), and (10E,12Z)-tetradecadien-1-ol (8), robust response at 10 µM. (B) Dose-dependent relationships; n = 4.
-
Stereochemical selectivity.
2013Co-Authors: Antony M. Hooper, John A. Pickett, Walter S LealAbstract:(A) Traces and (B) quantification of current responses from BmorOR1•BmorOrco-expressing oocytes perfused with four isomers of Bombykol at 0.1 µM. n = 5. Bars with the same letter arwe not significantly different (One-way ANOVA, P
Shogo Matsumoto - One of the best experts on this subject based on the ideXlab platform.
-
Screening for the Genes Involved in Bombykol Biosynthesis: Identification and Functional Characterization of Bombyx mori Acyl Carrier Protein.
Frontiers in endocrinology, 2011Co-Authors: Atsushi Ohnishi, Misato Kaji, Kana Hashimoto, Shogo MatsumotoAbstract:Species-specific sex pheromones released by female moths to attract conspecific male moths are synthesized de novo in the pheromone gland (PG) via fatty acid synthesis (FAS). Biosynthesis of moth sex pheromones is usually regulated by a neurohormone termed pheromone biosynthesis activating neuropeptide (PBAN), a 33-aa peptide that originates in the subesophageal ganglion. In the silkmoth, Bombyx mori, cytoplasmic lipid droplets (LDs), which store the sex pheromone (Bombykol) precursor fatty acid, accumulate in PG cells prior to eclosion. PBAN activation of the PBAN receptor stimulates lipolysis of the stored LD triacylglycerols (TAGs) resulting in release of the Bombykol precursor for final modification. While we have previously characterized a number of molecules involved in Bombykol biosynthesis, little is known about the mechanisms of PBAN signaling that regulate the TAG lipolysis in PG cells. In the current study, we sought to further identify genes involved in Bombykol biosynthesis as well as PBAN signaling, by using a subset of 312 expressed-sequence tag (EST) clones that are in either our B. mori PG cDNA library or the public B. mori EST databases, SilkBase and CYBERGATE, and which are preferentially expressed in the PG. Using RT-PCR expression analysis and an RNAi screening approach, we have identified another eight EST clones involved in Bombykol biosynthesis. Furthermore, we have determined the functional role of a clone designated BmACP that encodes B. mori acyl carrier protein (ACP). Our results indicate that BmACP plays an essential role in the biosynthesis of the Bombykol precursor fatty acid via the canonical FAS pathway during pheromonogenesis.
-
ORIGINAL RESEARCH ARTICLE
2011Co-Authors: Shogo Matsumoto, Misato Kaji, Kana Hashimoto, Shunsuke Moriyama Kitasato, Atsushi OhnishiAbstract:doi: 10.3389/fendo.2011.00092 Screening for the genes involved in Bombykol biosynthesis: identification and functional characterization of Bombyx mori acyl carrier protei
-
functional characterization of the bombyx mori fatty acid transport protein bmfatp within the silkmoth pheromone gland
Journal of Biological Chemistry, 2009Co-Authors: Atsushi Ohnishi, Kana Hashimoto, Kiyohiro Imai, Shogo MatsumotoAbstract:Fatty acid transport protein (FATP) is an evolutionarily conserved membrane-bound protein that facilitates the uptake of extracellular long chain fatty acids. In humans and mice, six FATP isoforms have been identified and their tissue-specific distributions suggest that each plays a discrete role in lipid metabolism in association with fatty acid uptake. While the presence of FATP homologs in insects has been demonstrated, their functional role remains to be characterized. Pheromonogenesis is defined as the dynamic period in which all machinery required for sex pheromone biosynthesis is generated and organized within the pheromone gland (PG) cells. By exploiting this unique system in the PG of the silkmoth, Bombyx mori, we found that BmFATP is predominantly expressed in the PG and undergoes up-regulation 1 day prior to eclosion. Before eclosion, B. mori PG cells accumulate cytoplasmic lipid droplets (LDs), which play a role in storing the pheromone (Bombykol) precursor fatty acid in the form of triacylglycerol. RNAi-mediated gene silencing of BmFATP in vivo significantly suppressed LD accumulation by preventing the synthesis of triacylglycerols and resulted in a significant reduction in Bombykol production. These results, in conjunction with the findings that BmFATP stimulates the uptake of extracellular long-chain fatty acids and BmFATP knockdown reduces cellular long-chain acyl-CoA synthetase activity, suggest that BmFATP plays an essential role in Bombykol biosynthesis by stimulating both LD accumulation and triacylglycerol synthesis via a process called vectorial acylation that couples the uptake of extracellular fatty acids with activation to CoA thioesters during pheromonogenesis.
-
Involvement of a bifunctional fatty-acyl desaturase in the biosynthesis of the silkmoth, Bombyx mori, sex pheromone
Proceedings of the National Academy of Sciences of the United States of America, 2004Co-Authors: Ken'ichi Moto, Tetsu Ando, Masataka G. Suzuki, J. Joe Hull, Ryuichiro Kurata, Shunya Takahashi, Masanobu Yamamoto, Kazuhiro Okano, Kiyohiro Imai, Shogo MatsumotoAbstract:The straight-chain C10 to C18 unsaturated aliphatic compounds containing an oxygenated functional group (aldehyde, alcohol, or acetate ester) derived from saturated C16 or C18 fatty acids are a major class of sex pheromone components produced by female moths. In the biosynthesis of these pheromone components, various combinations of limited chain-shortening and regio- and stereospecific desaturation reactions significantly contribute to the production of a vast number of the species-specific pheromone components in Lepidoptera. Biosynthesis of the silkmoth sex pheromone Bombykol, (E,Z)-10,12-hexadecadien-1-ol, involves two consecutive desaturation steps, the second of which is unique in that it generates a conjugated diene system from the Δ11-monoene C16 intermediate. In experiments designed to characterize the acyl-CoA desaturases responsible for Bombykol biosynthesis, we have cloned three cDNAs encoding desaturase family members from the pheromone gland of the inbred strain of the silkmoth, Bombyx mori. Transcript analyses by RT-PCR and subsequent functional assays using a Bac-to-Bac baculovirus expression system revealed that desat1 is the only desaturase gene prominently expressed during pheromonogenesis and that its gene product, B. mori Desat1, possesses both Z11 desaturation and Δ10,12-desaturation activities. Consequently, we have concluded that B. mori Desat1 is not only a bifunctional desaturase involved in Bombykol biosynthesis but that it is also the enzyme responsible for both desaturation steps.
-
Pheromone-producing cells in the silkmoth, Bombyx mori: identification and their morphological changes in response to pheromonotropic stimuli.
Journal of insect physiology, 2000Co-Authors: Adrien Fónagy, Norihiro Yokoyama, Keiju Okano, Sadahiro Tatsuki, Susumu Maeda, Shogo MatsumotoAbstract:A method to isolate functional clusters of viable pheromone gland cells of Bombyx mori was developed. The 8th-9th intersegmental invaginated membrane corresponding to the pheromone gland was dissected, trimmed and separated into two distinct layers, the outer and inner layers, by enzymatic digestion with papain. The outer layer mainly consists of cuticle, while the inner layer consists of homogeneous cells with many refractile granules. The solubilized microsome fraction prepared from the inner layer retained the ability to produce Bombykol in vitro, whereas the outer layer fraction did not produce Bombykol. Moreover, in tissue incubations, the inner layer - but not the outer layer - produced Bombykol in response to the pheromonotropic peptide TKYFSPRLamide, ionomycin and calcium ionophore A23187. These results indicate that the inner-layer cells are indeed the pheromone-producing cells, which retain their functional integrity after separation with papain. These cells could be cultured successfully in Grace's medium for at least 5days.The presence or absence of pheromonotropic stimuli prior to dissection greatly influenced the size, number and distribution of refractile granules in the cytoplasm of the pheromone-producing cells. Staining with Nile Red proved that these refractile granules were lipid droplets. When pheromone production was studied under normal conditions or stimulated in decapitated females with pheromone-biosynthesis-activating neuorpeptide (PBAN) charge, the size of lipid droplets observed in the pheromone-producing cells reduced prominently and their number increased dramatically with time. By contrast, when pheromone production was suppressed by decapitation, the size and number of the lipid droplets remained constant. Lipid droplets observed in the pheromone-producing cells could be carriers of pheromone precursors and/or the pheromone Bombykol. The present results suggest that the isolated cell preparation can be used for quantitative visualization of the cellular dynamics during pheromone production in B. mori.
Takeshi Sakurai - One of the best experts on this subject based on the ideXlab platform.
-
In vivo functional characterisation of pheromone binding protein-1 in the silkmoth, Bombyx mori
Nature Publishing Group, 2018Co-Authors: Yusuke Shiota, Takaaki Daimon, Takeshi Fujii, Yukio Ishikawa, Takeshi Sakurai, Hidefumi Mitsuno, Shigeru Matsuyama, Hideki Sezutsu, Ryohei KanzakiAbstract:Abstract Male moths detect sex pheromones emitted by conspecific females with high sensitivity and specificity by the olfactory sensilla on their antennae. Pheromone binding proteins (PBPs) are highly enriched in the sensillum lymph of pheromone sensitive olfactory sensilla and are supposed to contribute to the sensitivity and selectivity of pheromone detection in moths. However, the functional role of PBPs in moth sex pheromone detection in vivo remains obscure. In the silkmoth, Bombyx mori, female moths emit Bombykol as a single attractive sex pheromone component along with a small amount of bombykal that negatively modulates the behavioural responses to Bombykol. A pair of olfactory receptor neurons, specifically tuned to Bombykol or bombykal, co-localise in the trichodeum sensilla, the sensillum lymph of which contains a single PBP, namely, BmPBP1. We analysed the roles of BmPBP1 using BmPBP1-knockout silkmoth lines generated by transcription activator-like effector nuclease-mediated gene targeting. Electroantennogram analysis revealed that the peak response amplitudes of BmPBP1-knockout male antennae to Bombykol and bombykal were significantly reduced by a similar percentage when compared with those of the wild-type males. Our results indicate that BmPBP1 plays a crucial role in enhancing the sensitivity, but not the selectivity, of sex pheromone detection in silkmoths
-
A Single Sex Pheromone Receptor Determines Chemical Response Specificity of Sexual Behavior in the Silkmoth
2016Co-Authors: Bombyx Mori, Takeshi Sakurai, Hidefumi Mitsuno, Keiro Uchino, Stephan Shuichi Haupt, Fumio YokohariAbstract:In insects and other animals, intraspecific communication between individuals of the opposite sex is mediated in part by chemical signals called sex pheromones. In most moth species, male moths rely heavily on species-specific sex pheromones emitted by female moths to identify and orient towards an appropriate mating partner among a large number of sympatric insect species. The silkmoth, Bombyx mori, utilizes the simplest possible pheromone system, in which a single pheromone component, (E, Z)-10,12-hexadecadienol (Bombykol), is sufficient to elicit full sexual behavior. We have previously shown that the sex pheromone receptor BmOR1 mediates specific detection of Bombykol in the antennae of male silkmoths. However, it is unclear whether the sex pheromone receptor is the minimally sufficient determination factor that triggers initiation of orientation behavior towards a potential mate. Using transgenic silkmoths expressing the sex pheromone receptor PxOR1 of the diamondback moth Plutella xylostella in BmOR1-expressing neurons, we show that the selectivity of the sex pheromone receptor determines the chemical response specificity of sexual behavior in the silkmoth. Bombykol receptor neurons expressing PxOR1 responded to its specific ligand, (Z)-11-hexadecenal (Z11-16:Ald), in a dose-dependent manner. Male moths expressing PxOR1 exhibited typical pheromone orientation behavior and copulation attempts in response to Z11-16:Ald and to females of P. xylostella. Transformation of the Bombykol receptor neurons had no effect on their projections in the antennal lobe. These results indicate that activation of Bombykol receptor neurons alone is sufficien
-
cell based odorant sensor array for odor discrimination based on insect odorant receptors
Journal of Chemical Ecology, 2016Co-Authors: Maneerat Termtanasombat, Takeshi Sakurai, Hidefumi Mitsuno, Nobuo Misawa, Shinya Yamahira, Satoshi Yamaguchi, Teruyuki Nagamune, Ryohei KanzakiAbstract:The olfactory system of living organisms can accurately discriminate numerous odors by recognizing the pattern of activation of several odorant receptors (ORs). Thus, development of an odorant sensor array based on multiple ORs presents the possibility of mimicking biological odor discrimination mechanisms. Recently, we developed novel odorant sensor elements with high sensitivity and selectivity based on insect OR-expressing Sf21 cells that respond to target odorants by displaying increased fluorescence intensity. Here we introduce the development of an odorant sensor array composed of several Sf21 cell lines expressing different ORs. In this study, an array pattern of four cell lines expressing Or13a, Or56a, BmOR1, and BmOR3 was successfully created using a patterned polydimethylsiloxane film template and cell-immobilizing reagents, termed biocompatible anchor for membrane (BAM). We demonstrated that BAM could create a clear pattern of Sf21 sensor cells without impacting their odorant-sensing performance. Our sensor array showed odorant-specific response patterns toward both odorant mixtures and single odorant stimuli, allowing us to visualize the presence of 1-octen-3-ol, geosmin, Bombykol, and bombykal as an increased fluorescence intensity in the region of Or13a, Or56a, BmOR1, and BmOR3 cell lines, respectively. Therefore, we successfully developed a new methodology for creating a cell-based odorant sensor array that enables us to discriminate multiple target odorants. Our method might be expanded into the development of an odorant sensor capable of detecting a large range of environmental odorants that might become a promising tool used in various applications including the study of insect semiochemicals and food contamination.
-
Targeted disruption of a single sex pheromone receptor gene completely abolishes in vivo pheromone response in the silkmoth
Scientific reports, 2015Co-Authors: Takeshi Sakurai, Hidefumi Mitsuno, Hideki Sezutsu, Akihisa Mikami, Keiro Uchino, Masashi Tabuchi, Feng Zhang, Ryohei KanzakiAbstract:Male moths use species-specific sex pheromones to identify and orientate toward conspecific females. Odorant receptors (ORs) for sex pheromone substances have been identified as sex pheromone receptors in various moth species. However, direct in vivo evidence linking the functional role of these ORs with behavioural responses is lacking. In the silkmoth, Bombyx mori, female moths emit two sex pheromone components, Bombykol and bombykal, but only Bombykol elicits sexual behaviour in male moths. A sex pheromone receptor BmOR1 is specifically tuned to Bombykol and is expressed in specialized olfactory receptor neurons (ORNs) in the pheromone sensitive long sensilla trichodea of male silkmoth antennae. Here, we show that disruption of the BmOR1 gene, mediated by transcription activator-like effector nucleases (TALENs), completely removes ORN sensitivity to Bombykol and corresponding pheromone-source searching behaviour in male moths. Furthermore, transgenic rescue of BmOR1 restored normal behavioural responses to Bombykol. Our results demonstrate that BmOR1 is required for the physiological and behavioural response to Bombykol, demonstrating that it is the receptor that mediates sex pheromone responses in male silkmoths. This study provides the first direct evidence that a member of the sex pheromone receptor family in moth species mediates conspecific sex pheromone information for sexual behaviour.
-
Pheromone responsiveness threshold depends on temporal integration by antennal lobe projection neurons
Proceedings of the National Academy of Sciences of the United States of America, 2013Co-Authors: Masashi Tabuchi, Shigehiro Namiki, Takeshi Sakurai, Hidefumi Mitsuno, Hideki Sezutsu, Keiro Uchino, Toshiki Tamura, Ryo Minegishi, Takahiro Shiotsuki, Stephan Shuichi HauptAbstract:The olfactory system of male moths has an extreme sensitivity with the capability to detect and recognize conspecific pheromones dispersed and greatly diluted in the air. Just 170 molecules of the silkmoth (Bombyx mori) sex pheromone Bombykol are sufficient to induce sexual behavior in the male. However, it is still unclear how the sensitivity of olfactory receptor neurons (ORNs) is relayed through the brain to generate high behavioral responsiveness. Here, we show that ORN activity that is subthreshold in terms of behavior can be amplified to suprathreshold levels by temporal integration in antennal lobe projection neurons (PNs) if occurring within a specific time window. To control ORN inputs with high temporal resolution, channelrhodopsin-2 was genetically introduced into Bombykol-responsive ORNs. Temporal integration in PNs was only observed for weak inputs, but not for strong inputs. Pharmacological dissection revealed that GABAergic mechanisms inhibit temporal integration of strong inputs, showing that GABA signaling regulates PN responses in a stimulus-dependent fashion. Our results show that boosting of the PNs’ responses by temporal integration of olfactory information occurs specifically near the behavioral threshold, effectively defining the lower bound for behavioral responsiveness.
Ryohei Kanzaki - One of the best experts on this subject based on the ideXlab platform.
-
In vivo functional characterisation of pheromone binding protein-1 in the silkmoth, Bombyx mori
Nature Publishing Group, 2018Co-Authors: Yusuke Shiota, Takaaki Daimon, Takeshi Fujii, Yukio Ishikawa, Takeshi Sakurai, Hidefumi Mitsuno, Shigeru Matsuyama, Hideki Sezutsu, Ryohei KanzakiAbstract:Abstract Male moths detect sex pheromones emitted by conspecific females with high sensitivity and specificity by the olfactory sensilla on their antennae. Pheromone binding proteins (PBPs) are highly enriched in the sensillum lymph of pheromone sensitive olfactory sensilla and are supposed to contribute to the sensitivity and selectivity of pheromone detection in moths. However, the functional role of PBPs in moth sex pheromone detection in vivo remains obscure. In the silkmoth, Bombyx mori, female moths emit Bombykol as a single attractive sex pheromone component along with a small amount of bombykal that negatively modulates the behavioural responses to Bombykol. A pair of olfactory receptor neurons, specifically tuned to Bombykol or bombykal, co-localise in the trichodeum sensilla, the sensillum lymph of which contains a single PBP, namely, BmPBP1. We analysed the roles of BmPBP1 using BmPBP1-knockout silkmoth lines generated by transcription activator-like effector nuclease-mediated gene targeting. Electroantennogram analysis revealed that the peak response amplitudes of BmPBP1-knockout male antennae to Bombykol and bombykal were significantly reduced by a similar percentage when compared with those of the wild-type males. Our results indicate that BmPBP1 plays a crucial role in enhancing the sensitivity, but not the selectivity, of sex pheromone detection in silkmoths
-
cell based odorant sensor array for odor discrimination based on insect odorant receptors
Journal of Chemical Ecology, 2016Co-Authors: Maneerat Termtanasombat, Takeshi Sakurai, Hidefumi Mitsuno, Nobuo Misawa, Shinya Yamahira, Satoshi Yamaguchi, Teruyuki Nagamune, Ryohei KanzakiAbstract:The olfactory system of living organisms can accurately discriminate numerous odors by recognizing the pattern of activation of several odorant receptors (ORs). Thus, development of an odorant sensor array based on multiple ORs presents the possibility of mimicking biological odor discrimination mechanisms. Recently, we developed novel odorant sensor elements with high sensitivity and selectivity based on insect OR-expressing Sf21 cells that respond to target odorants by displaying increased fluorescence intensity. Here we introduce the development of an odorant sensor array composed of several Sf21 cell lines expressing different ORs. In this study, an array pattern of four cell lines expressing Or13a, Or56a, BmOR1, and BmOR3 was successfully created using a patterned polydimethylsiloxane film template and cell-immobilizing reagents, termed biocompatible anchor for membrane (BAM). We demonstrated that BAM could create a clear pattern of Sf21 sensor cells without impacting their odorant-sensing performance. Our sensor array showed odorant-specific response patterns toward both odorant mixtures and single odorant stimuli, allowing us to visualize the presence of 1-octen-3-ol, geosmin, Bombykol, and bombykal as an increased fluorescence intensity in the region of Or13a, Or56a, BmOR1, and BmOR3 cell lines, respectively. Therefore, we successfully developed a new methodology for creating a cell-based odorant sensor array that enables us to discriminate multiple target odorants. Our method might be expanded into the development of an odorant sensor capable of detecting a large range of environmental odorants that might become a promising tool used in various applications including the study of insect semiochemicals and food contamination.
-
Targeted disruption of a single sex pheromone receptor gene completely abolishes in vivo pheromone response in the silkmoth
Scientific reports, 2015Co-Authors: Takeshi Sakurai, Hidefumi Mitsuno, Hideki Sezutsu, Akihisa Mikami, Keiro Uchino, Masashi Tabuchi, Feng Zhang, Ryohei KanzakiAbstract:Male moths use species-specific sex pheromones to identify and orientate toward conspecific females. Odorant receptors (ORs) for sex pheromone substances have been identified as sex pheromone receptors in various moth species. However, direct in vivo evidence linking the functional role of these ORs with behavioural responses is lacking. In the silkmoth, Bombyx mori, female moths emit two sex pheromone components, Bombykol and bombykal, but only Bombykol elicits sexual behaviour in male moths. A sex pheromone receptor BmOR1 is specifically tuned to Bombykol and is expressed in specialized olfactory receptor neurons (ORNs) in the pheromone sensitive long sensilla trichodea of male silkmoth antennae. Here, we show that disruption of the BmOR1 gene, mediated by transcription activator-like effector nucleases (TALENs), completely removes ORN sensitivity to Bombykol and corresponding pheromone-source searching behaviour in male moths. Furthermore, transgenic rescue of BmOR1 restored normal behavioural responses to Bombykol. Our results demonstrate that BmOR1 is required for the physiological and behavioural response to Bombykol, demonstrating that it is the receptor that mediates sex pheromone responses in male silkmoths. This study provides the first direct evidence that a member of the sex pheromone receptor family in moth species mediates conspecific sex pheromone information for sexual behaviour.
-
Different concentration-response characteristics in dendrites and somata of antennal lobe (AL) projection neurons (PNs).
2014Co-Authors: Terufumi Fujiwara, Tomoki Kazawa, Stephan Shuichi Haupt, Ryohei KanzakiAbstract:A, Schematic diagram of loading a calcium indicator into PNs with a micropipette by local electroporation (left). The toroid glomerulus processing Bombykol is delineated by a dashed line. Fluorescence images of labeled PNs (middle) and the response to 1000 ng Bombykol in false colors (right) are shown. Dendritic and somatic regions of interest (ROIs) are indicated by boxes. D: dorsal, M: medial. Scale bar: 50 µm. B, Representative time courses of PN responses to Bombykol stimuli in the dendrites (left) and a soma (right). Black bars under time courses indicate the stimulus. C, Concentration-response characteristics of PN dendrites (magenta) and somata (green). Calcium responses were integrated over 3 s from stimulus onset. (P
-
Relation between calcium and spike responses in PNs.
2014Co-Authors: Terufumi Fujiwara, Tomoki Kazawa, Stephan Shuichi Haupt, Ryohei KanzakiAbstract:A, Fluorescence images of PNs labeled with calcium indicator (top) and the response to 1000 ng Bombykol in false colors (bottom). Spike responses were recorded from the labeled soma indicated by the arrowhead. The microelectrode for loose-patch recording is delineated by dashed lines and the ROI in the dendritic region is marked. D: dorsal, M: medial. Scale bars: 50 µm. B, Representative PN spike responses to Bombykol stimuli. The responses were recorded from the soma shown in (A). Black bar under the spike responses indicates stimulus. C, Concentration-response characteristics of PN spike responses. The response amplitudes were quantified using peak instantaneous spike frequency (peak ISF, left) and spike response duration (right). (P
Toru Shimada - One of the best experts on this subject based on the ideXlab platform.
-
Reinvestigation of the Sex Pheromone of the Wild Silkmoth Bombyx mandarina: The Effects of Bombykal and Bombykyl Acetate
Journal of Chemical Ecology, 2012Co-Authors: Takaaki Daimon, Tsuguru Fujii, Susumu Katsuma, Toru Shimada, Takeshi Fujii, Takeshi Yokoyama, Tetsuro Shinoda, Yukio IshikawaAbstract:Sex pheromone investigations of the domesticated silkmoth, Bombyx mori (Lepidoptera: Bombycidae), helped elucidate the molecular and physiological fundamentals of chemical communication in moths, yet little is known about pheromone evolution in bombycid species. Therefore, we reexamined the sex pheromone communication in the wild silkmoth, Bombyx mandarina , which is considered ancestral to B. mori . Our investigations revealed that (a) B. mandarina females produce ( E,Z )-10,12-hexadecadienol (Bombykol), but not ( E,Z )-10,12-hexadecadienal (bombykal) or ( E,Z )-10,12-hexadecadienyl acetate (bombykyl acetate), which are pheromone components in other bombycid moths; (b) antennae of male B. mandarina respond strongly to Bombykol as well as to bombykal and bombykyl acetate; and (c) bombykal and bombykyl acetate strongly inhibit attraction of B. mandarina males to Bombykol in the field. The present study clarifies the evolution of pheromone communication in bombycid moths.
-
Female sex pheromone and male behavioral responses of the bombycid moth Trilocha varians: comparison with those of the domesticated silkmoth Bombyx mori
Naturwissenschaften, 2012Co-Authors: Takaaki Daimon, Tsuguru Fujii, Susumu Katsuma, Takeshi Fujii, Yukio Ishikawa, Masaya Yago, Yumiko Nakajima, Toru ShimadaAbstract:Analysis of female sex pheromone components and subsequent field trap experiments demonstrated that the bombycid moth Trilocha varians uses a mixture of ( E , Z )-10,12-hexadecadienal (bombykal) and ( E,Z )-10,12-hexadecadienyl acetate (bombykyl acetate) as a sex pheromone. Both of these components are derivatives of ( E,Z )-10,12-hexadecadienol (Bombykol), the sex pheromone of the domesticated silkmoth Bombyx mori . This finding prompted us to compare the antennal and behavioral responses of T. varians and B. mori to Bombykol, bombykal, and bombykyl acetate in detail. The antennae of T. varians males responded to bombykal and bombykyl acetate but not to Bombykol, and males were attracted only when lures contained both bombykal and bombykyl acetate. In contrast, the antennae of B. mori males responded to all the three components. Behavioral analysis showed that B. mori males responded to neither bombykal nor bombykyl acetate. Meanwhile, the wing fluttering response of B. mori males to Bombykol was strongly inhibited by bombykal and bombykyl acetate, thereby indicating that bombykal and bombykyl acetate act as behavioral antagonists for B. mori males. T. varians would serve as a reference species for B. mori in future investigations into the molecular mechanisms underlying the evolution of sex pheromone communication systems in bombycid moths.
-
Female sex pheromone and male behavioral responses of the bombycid moth Trilocha varians: comparison with those of the domesticated silkmoth Bombyx mori
Naturwissenschaften, 2012Co-Authors: Takaaki Daimon, Tsuguru Fujii, Susumu Katsuma, Takeshi Fujii, Yukio Ishikawa, Masaya Yago, Yumiko Nakajima, Yu-feng Hsu, Toru ShimadaAbstract:Analysis of female sex pheromone components and subsequent field trap experiments demonstrated that the bombycid moth Trilocha varians uses a mixture of ( E , Z )-10,12-hexadecadienal (bombykal) and ( E,Z )-10,12-hexadecadienyl acetate (bombykyl acetate) as a sex pheromone. Both of these components are derivatives of ( E,Z )-10,12-hexadecadienol (Bombykol), the sex pheromone of the domesticated silkmoth Bombyx mori . This finding prompted us to compare the antennal and behavioral responses of T. varians and B. mori to Bombykol, bombykal, and bombykyl acetate in detail. The antennae of T. varians males responded to bombykal and bombykyl acetate but not to Bombykol, and males were attracted only when lures contained both bombykal and bombykyl acetate. In contrast, the antennae of B. mori males responded to all the three components. Behavioral analysis showed that B. mori males responded to neither bombykal nor bombykyl acetate. Meanwhile, the wing fluttering response of B. mori males to Bombykol was strongly inhibited by bombykal and bombykyl acetate, thereby indicating that bombykal and bombykyl acetate act as behavioral antagonists for B. mori males. T. varians would serve as a reference species for B. mori in future investigations into the molecular mechanisms underlying the evolution of sex pheromone communication systems in bombycid moths.
-
Sex-linked transcription factor involved in a shift of sex-pheromone preference in the silkmoth Bombyx mori
Proceedings of the National Academy of Sciences of the United States of America, 2011Co-Authors: Tsuguru Fujii, Susumu Katsuma, Takeshi Fujii, Yukio Ishikawa, Shigehiro Namiki, Hiroaki Abe, Takeshi Sakurai, Akio Ohnuma, Ryohei Kanzaki, Toru ShimadaAbstract:In the sex-pheromone communication systems of moths, odorant receptor (Or) specificity as well as higher olfactory information processing in males should be finely tuned to the pheromone of conspecific females. Accordingly, male sex-pheromone preference should have diversified along with the diversification of female sex pheromones; however, the genetic mechanisms that facilitated the diversification of male preference are not well understood. Here, we explored the mechanisms involved in a drastic shift in sex-pheromone preference in the silkmoth Bombyx mori using spli mutants in which the genomic structure of the gene Bmacj6, which encodes a class IV POU domain transcription factor, is disrupted or its expression is repressed. B. mori females secrete an ∼11:1 mixture of Bombykol and bombykal. Bombykol alone elicits full male courtship behavior, whereas bombykal alone shows no apparent activity. In the spli mutants, the behavioral responsiveness of males to Bombykol was markedly reduced, whereas bombykal alone evoked full courtship behavior. The reduced response of spli males to Bombykol was explained by the paucity of Bombykol receptors on the male antennae. It was also found that, in the spli males, neurons projecting into the toroid, a compartment in the brain where Bombykol receptor neurons normally project, responded strongly to bombykal. The present study highlights a POU domain transcription factor, Bmacj6, which may have caused a shift of sex-pheromone preference in B. mori through Or gene choice and/or axon targeting.
-
Molecular analysis of sex chromosome-linked mutants in the silkworm Bombyx mori
Journal of Genetics, 2010Co-Authors: Tsuguru Fujii, Toru ShimadaAbstract:In Bombyx mori , the W chromosome determines the female sex. A few W chromosome-linked mutations that cause masculinization of the female genitalia have been found. In female antennae of a recently isolated mutant, both female-type and male-type Bmdsx mRNAs were expressed, and BmOr1 (Bombykol receptor) and BmOr3 (bombykal receptor), which are predominantly expressed in the antennae of male moths, were expressed about 50 times more abundantly in the antennae of mutant females than in those of normal females. These mutants are valuable resources for the molecular analysis of the sexdetermination system. Besides the Fem gene, the quantitative egg size-determining gene Esd is thought to be present on theW chromosome, based on the observation that ZWW triploid moths produce larger eggs than ZZW triploids. The most recently updated B. mori genome assembly comprises 20.5 Mb of Z chromosome sequence. Using these sequence data, responsible genes or candidate genes for four Z-linked mutants have been reported. The od (distinct oily) and spli (soft and pliable) are caused by mutation in BmBLOS2 and Bmacj6 , respectively. Bmap is a candidate gene for Vg (vestigial). Similarly, Bmprm is a candidate gene for Md (muscle dystrophy), causing abnormal development of indirect flight muscle.