Naoki Mori

Publications (31)79.44 Total impact

• Article: Identification of plasmalogen in the gut of silkworm (Bombyx mori).

  Takako Aboshi, Ritsuo Nishida, Naoki Mori
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  ABSTRACT: Herbivorous insect species are constantly challenged with endogenous and exogenous oxidative stress. Consequently, they possess an array of antioxidant enzymes and small molecular weight antioxidants. Lipid-soluble small molecular antioxidants, such as tocopherols, have not been well studied in insects but may play important antioxidant roles. In this study, we identified plasmalogen phosphatidylethanolamines (pPEs) as well as α-, β/γ-, δ-tocopherol in the larvae of the silkworm Bombyx mori by LCMS analyses and examined their distribution. Plasmalogen are reported to inhibit the metal ion induced oxidation. The composition of tocopherols was the same among gut contents, gut tissues, and the other tissues. However, plasmalogens, a unique class of glycerophospholipids rich in polyunsaturated fatty acids and containing a vinyl ether bond at the sn-1 position, were mainly distributed in gut tissues. Plasmalogens might protect gut tissues from oxidation stress.
  Insect biochemistry and molecular biology 05/2012; 42(8):596-601. · 3.25 Impact Factor
• Article: Chemical ecology of astigmatid mites LXXXVII. S-(+)-isopiperitenone: re-identification of the alarm pheromone as the female sex pheromone in Tyrophagus similis (Acari: Acaridae).

  Gorou Maruno, Naoki Mori, Yasumasa Kuwahara
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  ABSTRACT: Behavioral analysis revealed that S-(+)-isopiperitenone [(S)-3-methyl-6-isopropenyl-2-cyclohexen-1-one], previously identified as an alarm pheromone, is also the female sex pheromone of Tyrophagus similis (Astigmata: Acaridae), showing maximum male attraction at a dose of 0.1 female equivalent. Although the antipode, R-(-)-isopiperitenone, was not detectable in the mite extract, this synthetic optical isomer (80% e.e.) also induced activity at a dose of 100 ng, a response indicative of S-(+)-isopiperitenone being the active compound. The average content was determined to be 38.5 ng per female and 19.8 ng per male. This is the first example of an astigmatid mite species possessing a compound that functions as an alarm as well as a sex pheromone.
  Journal of Chemical Ecology 01/2012; 38(1):36-41. · 2.66 Impact Factor
• Article: Phospholipid biosynthesis in the gut of Spodoptera litura larvae and effects of tannic acid ingestion.

  Takako Aboshi, Naoko Yoshinaga, Ritsuo Nishida, Naoki Mori
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  ABSTRACT: Tannins are polyphenols and defensive molecules occurring widely in plants. Dietary tannin may bind digestive enzymes of herbivores and affect them by reducing digestibility. In lepidopteran caterpillars, lysophosphatidylcholine (lysoPC), known as surfactants present in the guts, are thought to interfere with tannin-protein interactions. However, details of biosynthetic pathways of lysoPC in caterpillars have not been paid attention. Here, we investigated biosyntheses of lysoPC in Spodoptera litura larvae. S. litura larvae were fed on artificial diets enriched with [U-(13)C]linolenic acid for 3h, and then phospholipids in the gut contents were analyzed by LCMS-IT-TOF. Labeled linolenic acid was incorporated into lysoPC as well as diacylPC, diacylphosphatidylethanolamine (diacylPE) and diacylphosphatidylinositol (diacylPI). Detailed investigation on the biosynthesis revealed that [U-(13)C]linolenic acid was incorporated into phospholipids in gut tissues and then the biosynthesized phospholipids were released to the gut lumen, and then some of diacylPC were hydrolyzed to lysoPC in the gut lumen. When S. litura larvae were fed on artificial diets enriched with tannic acid, a significant increase in the activity to produce diacylPC in the gut tissues was observed. The activated diacylPC production leading to an increase of lysoPC in the larvae might be the adaptively-tuned mechanisms against plant tannins.
  Insect biochemistry and molecular biology 02/2010; 40(4):325-30. · 3.25 Impact Factor
• Article: Stereochemistry of female-specific normonoterpenes, sex pheromone candidates from the acarid mite, Tyreophagus sp. (Astigmata: Acaridae).

  Nobuhiro Shimizu, Kuniaki Miwa, Koji Noge, Ryota Yakumaru, Naoki Mori, Yasumasa Kuwahara
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  ABSTRACT: Two normonoterpenes were detected from an unidentified Tyreophagus sp. as new female-specific components. Both planar structures were identified to be 2,6-dimethyl-5-heptenal (1) and 2,6-dimethyl-5-hepten-1-ol (2) by GC/MS co-chromatography with synthetic 1 and 2. The stereochemistry of 2 was determined to be R by a GC analysis with a chiral column, while that of 1 was presumed to be similar to 2 based on the biosynthetic aspects.
  Bioscience Biotechnology and Biochemistry 10/2009; 73(10):2332-4. · 1.28 Impact Factor
• Article: Efficient incorporation of free oxygen into volicitin in Spodoptera litura common cutworm larvae.

  Chihiro Ishikawa, Naoko Yoshinaga, Takako Aboshi, Ritsuo Nishida, Naoki Mori
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  ABSTRACT: Volicitin [N-(17-hydroxylinolenoyl)-L-glutamine] has previously been identified from the lepidopteran larval regurgitant as an elicitor of plant volatile emission. The efficient incorporation of free oxygen into volicitin by Spodoptera litura larvae is demonstrated here by rearing them under (18)O(2) for three days. (18)O-labeling of the hydroxyl group of volicitin was confirmed by liquid chromatography/mass spectrometry-ion trap-time-of-flight (LC/MS-IT-TOF) and suggests the activity of a monooxygenase in volicitin biosynthesis.
  Bioscience Biotechnology and Biochemistry 09/2009; 73(8):1883-5. · 1.28 Impact Factor
• Article: Species-specific glucosylation of DIMBOA in larvae of the rice Armyworm.

  Hiroaki Sasai, Masahiro Ishida, Kenjiro Murakami, Naoko Tadokoro, Atsushi Ishihara, Ritsuo Nishida, Naoki Mori
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  ABSTRACT: DIMBOA [2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one] is a benzoxazinoid (Bx), part of the chemical defense system of graminaceous plants such as maize, wheat, and rye. When Bombyx mori larvae were fed artificial diets containing DIMBOA, they died in three days. In contrast, Mythimna separata larvae, a serious pest of rice, maize, sorghum, wheat etc., grew well on the same diets. Three kinds of glucosides [1-(2-hydroxy-4-methoxyphenylamino)-1-deoxy-beta-glucopyranoside-1,2-carbamate (methoxy glucoside carbamate), 2-O-beta-glucopyranosyl-4-hydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA-2-O-Glc), and 2-O-beta-glucopyranosyl-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (HMBOA-2-O-Glc)] were identified by LC-MS and NMR analyses from the frass of M. separata that had been fed on a DIMBOA-containing diet. Furthermore, the incubation of DIMBOA with a midgut tissue suspension of M. separata in the presence of UDP-D-glucose generated DIMBOA-2-O-Glc. These findings strongly suggest that glucosylation by UDP-glucosyltransferase(s) was important for detoxification to circumvent the defenses of host plants against M. separata larvae.
  Bioscience Biotechnology and Biochemistry 07/2009; 73(6):1333-8. · 1.28 Impact Factor
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  Article: Active role of fatty acid amino acid conjugates in nitrogen metabolism in Spodoptera litura larvae.

  Naoko Yoshinaga, Takako Aboshi, Hiroaki Abe, Ritsuo Nishida, Hans T Alborn, James H Tumlinson, Naoki Mori
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  ABSTRACT: Since the first fatty acid amino acid conjugate (FAC) was isolated from regurgitant of Spodoptera exigua larvae in 1997 [volicitin: N-(17-hydroxylinolenoyl)-L-glutamine], their role as elicitors of induced responses in plants has been well documented. However, studies of the biosyntheses and the physiological role of FACs in the insect have been minimal. By using (14)C-labeled glutamine, glutamic acid, and linolenic acid in feeding studies of Spodoptera litura larvae, combined with tissue analyses, we found glutamine in the midgut cells to be a major source for biosynthesis of FACs. Furthermore, 20% of the glutamine moiety of FACs was derived from glutamic acid and ammonia through enzymatic reaction of glutamine synthetase (GS). To determine whether FACs improve GS productivity, we studied nitrogen assimilation efficiency of S. litura larvae fed on artificial diets containing (15)NH(4)Cl and glutamic acid. When the diet was enriched with linolenic acid, the nitrogen assimilation efficiency improved from 40% to >60%. In the lumen, the biosynthesized FACs are hydrolyzed to fatty acids and glutamine, which are reabsorbed into tissues and hemolymph. These results strongly suggested that FACs play an active role in nitrogen assimilation in Lepidoptera larva and that glutamine containing FACs in the gut lumen may function as a form of storage of glutamine, a key compound of nitrogen metabolism.
  Proceedings of the National Academy of Sciences 11/2008; 105(46):18058-63. · 9.68 Impact Factor
• Article: Induction of allergic contact dermatitis by astigmatid mite-derived monoterpene, alpha-acaridial.

  Toshio Sasai, Yunosuke Hirano, Sayaka Maeda, Isamu Matsunaga, Atsushi Otsuka, Daisuke Morita, Ritsuo Nishida, Hideo Nakayama, Yasumasa Kuwahara, Masahiko Sugita, Naoki Mori
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  ABSTRACT: alpha-Acaridial [2(E)-(4-methyl-3-pentenyl)butenedial] is a novel monoterpene secreted from the house dust mites. Because of its molecular nature of a highly reactive, small lipidic compound, we addressed whether alpha-acaridial might function as a haptenic allergen that induced allergic contact dermatitis. Mice sensitized with alpha-acaridial were challenged by the same antigen on the ear skin. After 2 days, significant ear swelling with a prominent infiltration of CD4(+) T lymphocytes was observed. In vitro, alpha-acaridial exhibited an outstanding ability to quickly interact with and chemically modify a reference protein. Virtually all cysteine residues and a sizable fraction of lysine residues were found to be selectively modified, suggesting that alpha-acaridial could potentially interact with any proteins. Previously, numerous mite-derived proteinaceous allergens have been associated with contact dermatitis. Our study now emphasizes that small lipidic compounds released from mites comprise a new class of mite allergens, and therefore, is of significant medical implications.
  Biochemical and Biophysical Research Communications 11/2008; 375(3):336-40. · 2.48 Impact Factor
• Article: Geraniol dehydrogenase, the key enzyme in biosynthesis of the alarm pheromone, from the astigmatid mite Carpoglyphus lactis (Acari: Carpoglyphidae).

  Koji Noge, Makiko Kato, Naoki Mori, Michihiko Kataoka, Chihiro Tanaka, Yuji Yamasue, Ritsuo Nishida, Yasumasa Kuwahara
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  ABSTRACT: Geraniol dehydrogenase (GeDH), which plays an important role in the biosynthesis of neral, an alarm pheromone, was purified from the astigmatid mite Carpoglyphus lactis. The enzyme was obtained in an apparently homogeneous and active form after 1879-fold purification through seven steps of chromatography. Car. lactis GeDH was determined to be a monomer in its active form with a relative molecular mass of 42 800, which is a unique subunit structure in comparison with already established alcohol dehydrogenases. Car. lactis GeDH oxidized geraniol into geranial in the presence of NAD+. NADP+ was ineffective as a cofactor, suggesting that Car. lactis GeDH is an NAD+-dependent alcohol dehydrogenase. The optimal pH and temperature for geraniol oxidation were determined to be pH 9.0 and 25 degrees C, respectively. The Km values for geraniol and NAD+ were 51.0 microm and 59.5 microm, respectively. Car. lactis GeDH was shown to selectively oxidize geraniol, whereas its geometrical isomer, nerol, was inert as a substrate. The high specificity for geraniol suggests that Car. lactis GeDH specializes in the alarm pheromone biosynthesis of Car. lactis. Car. lactis GeDH is composed of 378 amino acids. Structurally, Car. lactis GeDH showed homology with zinc-dependent alcohol dehydrogenases found in mammals and a mosquito (36.6-37.6% identical), and the enzyme was considered to be a member of the medium-chain dehydrogenase/reductase family, in view of the highly conserved sequences of zinc-binding and NAD+-binding sites. Phylogenetic analyses indicate that Car. lactis GeDH could be categorized as a new class, different from other established alcohol dehydrogenases.
  FEBS Journal 07/2008; 275(11):2807-17. · 3.79 Impact Factor
• Article: Fatty acid amides, previously identified in caterpillars, found in the cricket Teleogryllus taiwanemma and fruit fly Drosophila melanogaster larvae.

  Naoko Yoshinaga, Takako Aboshi, Chihiro Ishikawa, Masao Fukui, Masami Shimoda, Ritsuo Nishida, Cameron G Lait, James H Tumlinson, Naoki Mori
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  ABSTRACT: Fatty acid amides (FAAs) are known elicitors that induce plants to release volatile compounds that, in turn, attract foraging parasitoids. Since the discovery of volicitin [N-(17-hydroxylinolenoyl)-L-glutamine] in the regurgitant of larval Spodoptera exigua, a series of related FAAs have been identified in several other species of lepidopteran caterpillars. We screened 13 non-lepidopteran insects for the presence of FAAs and found that these compounds were present in adults of two closely related cricket species, Teleogryllus taiwanemma and T. emma (Orthoptera: Gryllidae), and larvae of the fruit fly, Drosophila melanogaster (Diptera: Drosophilidae). When analyzed by liquid chromatography/mass spectrometry-ion trap-time-of-flight (LCMS-IT-TOF), the gut contents of both crickets had nearly identical FAA composition, the major FAAs comprising N-linolenoyl-L-glutamic acid and N-linoleoyl-L-glutamic acid. There were also two previously uncharacterized FAAs that were thought to be hydroxylated derivatives of these glutamic acid conjugates, based on their observed fragmentation patterns. In addition to these four FAAs containing glutamic acid, N-linolenoyl-L-glutamine and a small amount of volicitin were detected. In D. melanogaster, N-linolenoyl-L-glutamic acid and N-linoleoyl-L-glutamic acid were the major FAAs found in larval extracts, while hydroxylated glutamic acid conjugates, volicitin and N-linolenoyl-L-glutamine, were detected as trace components. Although these FAAs were not found in ten of the insects studied here, their identification in two additional orders of insects suggests that FAAs are more common than previously reported and may have physiological roles in a wide range of insects besides caterpillars.
  Journal of Chemical Ecology 08/2007; 33(7):1376-81. · 2.66 Impact Factor
• Article: Identification of crinosterol from astigamatid mites.

  Kenjiro Murakami, Bunta Watanabe, Ritsuo Nishida, Naoki Mori, Yasumasa Kuwahara
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  ABSTRACT: A 24-alkylsterol, crinosterol [(24S)-24-methylcholesta-5,22(E)-dien-3beta-ol] has been isolated from sea-dwelling animals, protists and plants. Here, we identified crinosterol from nine species of mites (Acari). The compound was identified by using (1)H-NMR analysis and GCMS spectral data along with the HPLC retention time by comparing with those of the synthesized compound. As far as we know, this is the first report on the identification of crinosterol from arthropods. Furthermore, after Rhizoglyphus robini were fed on artificial diets with d(3)-methionine, d(2)-crinosterol was detected from the mite's extracts. The incorporation of two deuterium atoms into the sterol indicated that a d(3)-methyl group was introduced into the C24 of the side chain to form crinosterol. Although the details of the biosynthesis of crinosterol remain unknown, the discovery of crinosterol in the mites implies the existence of interesting sterol metabolisms in the animals.
  Insect Biochemistry and Molecular Biology 06/2007; 37(5):506-11. · 3.25 Impact Factor
• Article: Efficient incorporation of unsaturated fatty acids into volicitin-related compounds in Spodoptera litura (Lepidoptera: Noctuidae).

  Takako Aboshi, Naoko Yoshinaga, Koji Noge, Ritsuo Nishida, Naoki Mori
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  ABSTRACT: We introduced efficient incorporation of unsaturated fatty acids into volicitin [N-(17-hydroxylinolenoyl)-L-glutamine] and N-linolenoyl-L-glutamine, insect-derived elicitors of plant volatiles, in the common cutworms Spodoptera litura by the incubation of larval gut tissues with unsaturated (linolenic, linoleic, and oleic acids) or saturated fatty acids (palmitic and stearic acids) sodium salt, and L-[alpha-(15)N]glutamine.
  Bioscience Biotechnology and Biochemistry 03/2007; 71(2):607-10. · 1.28 Impact Factor
• Article: Absolute configuration of volicitin from the regurgitant of lepidopteran caterpillars and biological activity of volicitin-related compounds.

  Yoshitsugu Sawada, Naoko Yoshinaga, Kenji Fujisaki, Ritsuo Nishida, Yasumasa Kuwahara, Naoki Mori
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  ABSTRACT: Volicitin [N-(17-hydroxylinolenoyl)-L-glutamine] and N-linolenoyl-L-glutamine are known as insect-produced plant volatile elicitors. The absolute configuration of the hydroxylinolenoyl moiety of volicitin from three noctuid species, Helicoverpa armigera, Mythimna separata and Spodoptera litura, was determined to be all 17S in high enantiomeric excess. When treated with 30 pmol of (17S)- and (17R)-volicitin, corn seedlings were induced to release volatiles, there being no significant difference in the amount released between the two isomers. On the other hand, N-linolenoyl-L-glutamine was only about 30% as active as volicitin. Among several synthesized N-linolenoylamino acid conjugates, only the L-glutamine conjugate induced the emission of volatile organic compounds. These results show that the L-glutamine moiety of volicitin played a more critical role than the hydroxyl moiety, although both moieties affected the elicitor activity inducing the release of volatiles.
  Bioscience Biotechnology and Biochemistry 10/2006; 70(9):2185-90. · 1.28 Impact Factor
• Article: A hemiterpene glucoside as a probing deterrent of the bean aphid, Megoura crassicauda, from a non-host vetch, Vicia hirsuta.

  Naohiro Ohta, Naoki Mori, Yasumasa Kuwahara, Ritsuo Nishida
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  ABSTRACT: The bean aphid, Megoura crassicauda Mordvilko, feeds selectively on plants belonging to the genus Vicia (Fabaceae). However, it never infests the tiny vetch, V. hirsuta (L.) Gray. The aphid appeared to discriminate between host and non-host plants by tasting specific chemicals during penetration of its stylet into the plant tissues. The aphid, after being stimulated by specific probing stimulants, deposited characteristic proteinous stylet sheaths through a parafilm membrane, which has one side in contact with an extract solution of Vicia angustifolia. However, an addition of a V. hirsuta extract to the medium strongly inhibited the salivary sheath formation. A specific probing deterrent was isolated from a V. hirsuta extract by monitoring the inhibitory effect, and identified as (E)-2-methyl-2-butene-1,4-diol 4-O-beta-d-glucopyranoside. A mixture of the glycoside and the stimulatory V. angustifolia fraction in the same equivalency found in plants significantly decreased the probing activity in M. crassicauda. Since the stylet insertion process is a crucial step for the aphid's settlement on a plant, the glycoside seems to act as an effective chemical barrier for V. hirsuta.
  Phytochemistry 04/2006; 67(6):584-8. · 3.35 Impact Factor
• Article: Ultraweak photon emission from herbivory-injured maize plants.

  Naoko Yoshinaga, Kimihiko Kato, Chizuko Kageyama, Kenji Fujisaki, Ritsuo Nishida, Naoki Mori
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  ABSTRACT: Following perception of herbivory or infection, plants exhibit a wide range of inducible responses. In this study, we found ultraweak photon emissions from maize leaves damaged by Helicoverpa armigera (Noctuidae). Interestingly, mechanically damaged maize leaves treated with caterpillar regurgitants emitted the same intensity and pattern of photon emissions as those from maize leaves damaged by caterpillars. Furthermore, two-dimensional imaging of the leaf section treated with the oral secretions clearly shows that photon emissions were observed specifically at the lip of the wound exposed to the secretions. These results suggest that the direct interaction between maize leaf cells and chemicals contained in caterpillar regurgitants triggers these photon emissions.
  Naturwissenschaften 02/2006; 93(1):38-41. · 2.28 Impact Factor
• Article: Scheloribatid mites as the source of pumiliotoxins in dendrobatid frogs.

  Wataru Takada, Tomoyo Sakata, Satoshi Shimano, Yoshinari Enami, Naoki Mori, Ritsuo Nishida, Yasumasa Kuwahara
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  ABSTRACT: The strawberry poison frog Dendrobates pumilio (Anura: Dendrobatidae) and related poison frogs contain a variety of dendrobatid alkaloids that are considered to be sequestered through the consumption of alkaloid-containing arthropods microsympatrically distributed in the habitat. In addition to ants, beetles, and millipedes, we found that adults of two species of oribatid mites belonging to the cohort Brachypylina, trophically a lower level of animal than ants and beetles, contain dendrobatid alkaloids. Gas chromatography/mass spectrometry (GC/MS) of hexane extracts of adult Scheloribates azumaensis (Oribatida: Acari) revealed the presence of not only pumiliotoxin 251D (8-hydroxy-8-methyl-6-(2'-methylhexylidene)-1-azabicyclo[4.3.0]nonane), but also precoccinelline 193C and another coccinelline-type alkaloid. From the corresponding extracts of an unidentified Scheloribates sp., pumiliotoxin 237A (8-hydroxy-8-methyl-6-(2'-methylpentylidene)-1-azabicyclo[4.3.0]nonane) was detected as a minor component, and identified by synthesis. The presence of related alkaloids, namely deoxypumiliotoxin 193H, a 6,8-diethyl-5-propenylindolizidine, and tentatively, a 1-ethyl-4-pentenynylquinolizidine, were indicated by the GC/MS fragmentation patterns, along with at least another six unidentified alkaloid components. Thus, one possible origin of pumiliotoxins, coccinellid alkaloids, and certain izidines found in poison frogs may be mites of the genus Scheloribates and perhaps related genera in the suborder Oribatida.
  Journal of Chemical Ecology 11/2005; 31(10):2403-15. · 2.66 Impact Factor
• Article: In vitro biosynthesis of volicitin in Spodoptera litura.

  Naoko Yoshinaga, Nobuyoshi Morigaki, Fumio Matsuda, Ritsuo Nishida, Naoki Mori
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  ABSTRACT: Volicitin [N-(17-hydroxylinolenoyl)-L-glutamine] and N-linolenoyl-L-glutamine, originally identified in the regurgitant of Spodoptera exigua, induce damaged corn leaves to release volatile compounds which enable parasitic wasps to locate host caterpillars. Here we demonstrate the in vitro biosynthesis of volicitin for the first time by using gut tissues of Spodoptera litura larvae, as well as N-linolenoyl-L-glutamine. When crop, midgut tissues, peritrophic membrane and gut contents isolated from S. litura were incubated with sodium linolenate and L-[alpha-15N] glutamine, not only 15N-labeled N-linolenoyl-L-glutamine but 15N-labeled volicitin was detected mainly in the midgut incubation by LCMS and LCMSMS analysis. In contrast, there were negligible amounts of the newly biosynthesized compounds in the gut content incubation. Furthermore, the microsomal fraction obtained from the gut tissues clearly showed specific incorporation of glutamine. This substrate selectivity accounts for the exclusive uptake of glutamine by fatty acid amides (FAAs) in the noctuid caterpillars, even though glutamine was not a major component in the regurgitant. Additionally, intensive chemical analyses revealed that more than 20% of glutamine in hemolymph was present as conjugates in gut contents. These results suggest that FAA compounds are actively synthesized by caterpillar tissues and might play important physiological role(s) in glutamine metabolism.
  Insect Biochemistry and Molecular Biology 03/2005; 35(2):175-84. · 3.25 Impact Factor
• Article: Identification of astigmatid mites using the second internal transcribed spacer (ITS2) region and its application for phylogenetic study.

  Koji Noge, Naoki Mori, Chihiro Tanaka, Ritsuo Nishida, Mitsuya Tsuda, Yasumasa Kuwahara
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  ABSTRACT: The second internal transcribed spacer (ITS2) of nuclear ribosomal DNA from 73 specimens of Astigmata was analyzed by PCR amplification and DNA sequencing. The length of the ITS2 region varied from 282 to 592 bp. The interspecific variation based on consensus sequences was more than 4.1%, while the intraspecific or intra-individual variation was from 0 to 5.7%. The variation between geographically separated populations (0-3.2%) was almost the same as the variation within strains. The sequences of the ITS2 region of Astigmata were concluded to be species-specific. The phylogenetic tree inferred from the ITS2 region supported Zachvatkin's morphological classification in the subfamily Rhizoglyphinae. The species-specific ITS2 sequence is useful for the species identification of astigmatid mites and for studying low-level phylogenetic relationships.
  Enperimental and Applied Acarology 02/2005; 35(1-2):29-46. · 1.73 Impact Factor
• Article: S-isorobinal as the female sex pheromone from an alarm pheromone-emitting mite, Rhizoglyphus setosus.

  Atsuko Mizoguchi, Kenjiro Murakami, Nobuhiro Shimizu, Naoki Mori, Ritsuo Nishida, Yasumasa Kuwahara
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  ABSTRACT: The female sex pheromone of Rhizoglyphus setosus Manson (Astigmata: Acaridae) was identified as S-isorobinal (4S-4-isopropenyl-3-oxo-1-cyclohexene-1-carboxyaldehyde), which stimulated males sexually and enhanced the frequency of the male's tapping and mounting behavior. Although the female hexane extract indicated no sign of sex pheromone activity against tested males, possibly due to the presence of the alarm pheromone neryl formate, an SiO2 column fraction containing isorobinal elicited sex pheromone activity at a dose of one female equivalent. The stereochemistry of natural isorobinal was identified as S by an HPLC using a chiral column. Both S- and R-isorobinals exhibited maximum activity at the same dose of 1 and 10 ng with a convex dose-response relationship. Amounts of S-isorobinal were determined to be 11.7 +/- 1.0 ng per female and 6.4 +/- 1.3 ng per male by GLC. This is the second example of two pheromones (the alarm pheromone neryl formate, and the sex pheromone S-isorobinal) demonstrated to be components of the same opisthonotal gland secretion.
  Enperimental and Applied Acarology 02/2005; 36(1-2):107-17. · 1.73 Impact Factor
• Article: Accumulation of HDMBOA-Glc is induced by biotic stresses prior to the release of MBOA in maize leaves.

  Akira Oikawa, Atsushi Ishihara, Chihiro Tanaka, Naoki Mori, Mitsuya Tsuda, Hajime Iwamura
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  ABSTRACT: The effects of biotic stresses on the contents of benzoxazinones (Bxs) were investigated in maize leaves. When the causal agent of southern corn leaf blight, Bipolaris maydis, was inoculated on the third leaf, the amount of 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one glucoside (HDMBOA-Glc) increased, reaching a maximum level 48 h after inoculation. The inoculation of weakly pathogenic Curvularia lunata and non-pathogenic Alternaria alternata also resulted in accumulation of HDMBOA-Glc, and filtrates of the cultures of B. maydis, C. lunata and A. alternata also showed the accumulation of elicitor-active compounds by the fungi. Furthermore the infection of B. maydis induced formation of dark brown lesions, where most abundant Bx-related compound was 6-methoxy-2-benzoxazolinone (MBOA). The later is formed by degradation of DIMBOA and HDMBOA, whereas HDMBOA-Glc was most abundant in the surrounding green tissues. Among the Bx-related compounds, MBOA exhibited the strongest inhibition of the germination of the conidia and of the growth of germ tubes of B. maydis, C. lunata and A. alternata. In addition to fungal infection, the feeding by rice armyworm larvae resulted in HDMBOA-Glc accumulation. These findings are discussed in relation to the possible ecological relevance of the conversion of DIMBOA-Glc into HDMBOA-Glc.
  Phytochemistry 12/2004; 65(22):2995-3001. · 3.35 Impact Factor