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Volume 20, Issue 1
Displaying 1-13 of 13 articles from this issue
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Katsuji WATANABE, Eiji TANIGUCHI1995 Volume 20 Issue 1 Pages 1-8
Published: February 20, 1995
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSThe factors affecting growth regulating activity of 2-(3′-phenylpropyl)phenylacetic acids and benzoic acids were investigated by conformational analyses and their steric parameters estimated from molecular mechanistic calculation. The rotational barrier of the bond (∅3) between 3′-phenylpropyl moiety and the first phenyl ring (Ar1) was existed around 180° in the less biologically active phenylacetic acids with a thiazole 1, 3-dioxopropyl or 1-oxopropenyl (the bridging system), while the rotational barrier disappeared in the more active phenylacetic acids with a pyrazole or oxazole in the bridging system. Planar conformation with ∅3=180°, which can be superposed on the highly active fixed ring phenylacetic acid derivative, 2-phenyl-5H-pyrazolo[5, 1-a]isoquinolin-5-one, was postulated as the biologically active conformation. The larger bond angle (∅) between An1 and Ar2, which diminished the rotational barrier of ∅3 caused by steric repulsion between the bridging system and methylene protons of the carboxymethyl group, was prerequisite for the higher plant growth regulating activity of the phenylacetic acid. While it was not prerequisite for benzoic acids without methylene protons.View full abstractDownload PDF (893K) -
Hiroshi OKIMOTO, Chi-Hwan LIM, Keiichiro NISHIMURA, Tamio UENO1995 Volume 20 Issue 1 Pages 9-15
Published: February 20, 1995
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSThe insecticidal activity of a set of injected dimethyl(substituted phenyl)silylmethyl meta-phenoxybenzyl ethers was measured against American cockroaches. The effects of aromatic substituents in the phenylsilyl moiety on the activity were position-specific. Substituents at the ortho and meta positions were unfavorable to the activity. Variations in the potency measured under conditions where the oxidative metabolic mechanism was inhibited were quantitatively analyzed using the physicochemical parameters of the aromatic substituents on the phenylsilyl moiety and molecular hydrophobicity. Variations in the potency were parabolically related to the hydrophobicity. The activity increased with the maximum width of the substituents.View full abstractDownload PDF (855K) -
Toshiro MIYAKE, Takashi MITSUI1995 Volume 20 Issue 1 Pages 17-24
Published: February 20, 1995
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSThe anti-juvenile hormone, precocene-2, showed multiple biological activity against the whitebacked rice planthopper, Sogatella furcifera. When newly hatched nymphs were released on rice plants treated with 500ppm of precocene-2 and continuously contacted with the chemicals, about half of the insects died within the first stadium (rapid toxicity). The other half survived through the following two or three nymphal stadia and then developed into precocious adults in the fourth or fifth stadium (prothetely). In this case, the insects seem to have been rather strongly affected by the anti-JH activity of precocene-2. On the other hand, when the insects were transferred from the treated rice plants to untreated ones on two, four and six days after the release, a large portion of the surviving insects (41.9% at maximum) developed into supernumerary nymphs in the sixth stadium (metathetely). In this case, the insects were supposed to have been incompletely affected by the activity of precocene-2. A juvenile hormone analog, NC-170, induced metathetely by itself, but none of the natural JH-1, JH-2 and JH-3 showed any morphogenetic effect. In addition, NC-170 rescued the prothetely induced by precocene-2, but the three natural JH's did not.View full abstractDownload PDF (7845K) -
Inhibitors of the Pheromone Biosynthesis in Bombyx moriTetsu ANDO, Ryuta OHNO, Kazuhisa IKEMOTO, Yohko YAJIMA1995 Volume 20 Issue 1 Pages 25-32
Published: February 20, 1995
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESS11, 12-Methylenehexadec-11-enoic acid and the amide were synthesized by the method of Baird et al. (1992) via a key intermediate, 1, 2, 2-tribromo-1-butylcyclopropane, which was debrominated and coupled with an alkylhalide resulting in a dialkylcyclopropene. Their activities as inhibitors of pheromone biosynthesis were examined with virgin females of the silkworm moth, Bombyx mori, in vivo. Bombykol titer diminished in the pheromone glands treated with the cyclopropenes, and experiments utilizing [1-14C] or [16, 16, 16-2H3]-hexadecanoic acids as a biosynthetic precursor showed that the cyclopropenes completely inhibited incorporation of the isotopes into bombykol and (Z)-11-hexadecen-1-ol at the dose of 1μg per pheromone gland but accelerated incorporation into hexadecan-1-ol. These results revealed the acid and amide with a propene ring at the 11-position are inhibitors of desaturation step(s), Δ11-desaturation and possibly Δ10, 12-desaturation, in the biosynthetic pathway. The nitrite derivative with the propene ring did not inhibit the bombykol biosynthesis.View full abstractDownload PDF (1031K) -
Izuru YAMAMOTO, Goro YABUTA, Motohiro TOMIZAWA, Takayuki SAITO, Toru M ...1995 Volume 20 Issue 1 Pages 33-40
Published: February 20, 1995
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSThe binding study on nicotinoids, neonicotinoids and the related compounds using [3H]α-bungarotoxin and [3H]nicotine as probes revealed that binding to the recognition site of nicotinic acetylcholine receptor (nAChR) in insects requires the molecules to have 3-pyridylmethylamino moiety, while high ionization in vertebrates. When [3H]phencyclidine was used as a probe for the ion channel opening of Torpedo nAChR, it was indicated that high ionization of the molecule is important to be agonistic, although the presence of 3-pyridylmethylamino moiety is preferred. 15N NMR of the amino nitrogen atom of nicotinoids and the corresponding one of neonicotinoids indicated that the latter was far deshielded as compared with the former. The result implies that the unshared electron pair on the concerned nitrogen atom is delocalized by the presence of strong electron-withdrawing group and the nitrogen atom becomes partially positive. Such nitrogen is enough to interact with the insect nAChR, but not with the vertebrate one. The overall results explain why nicotine is highly toxic to mammals and rather limited in insecticidal activity, whereas imidacloprid is highly insecticidal and low in mammalian toxicity.View full abstractDownload PDF (898K) -
Tetsushi IHARA, Tetsuji IIDA, Seiji TAKASUKA, Hitoshi KOHNO, Yukiharu ...1995 Volume 20 Issue 1 Pages 41-47
Published: February 20, 1995
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSUsing autotrophic Scenedesmus acutus cells incubated in the light and Echinochloa utilis culture, a series of isomeric compounds, namely 5-arylimino-3, 4-tetramethylene-1, 3, 4-thiadiazolidine-2-thiones (thiadiazolidine-thiones) and 4-aryl-1, 2-tetramethylene-1, 2, 4-triazolidine-3, 5-dithiones (triazolidine-dithiones), were assayed with respect to growth inhibition, decrease of chlorophyll contents, protoporphyrin-IX accumulation and light-induced ethane formation level. The both types of phytotoxic compounds decreased chlorophyll contents, caused protoporphyrin-IX accumulation and ethane evolution, and inhibited growth of Scenedesmus cells. They inhibited also protoporphyrinogen-IX oxidase, which led to rapid accumulation of protoporphyrin-IX, an intermediate of chlorophyll biosynthesis, just like peroxidizing herbicides such as p-nitrodiphenyl ethers and cyclic imides. Our comparative data on different sets of the aforementioned parameters suggest that both the thiadiazolidinethiones and triazolidine-dithiones are grouped as peroxidizing herbicides, affecting a crucial enzyme in the chlorophyll biosynthesis and inducing ethane formation by cell membrane destruction.View full abstractDownload PDF (872K) -
Motohiro TOMIZAWA, Hiroko OTSUKA, Toru MIYAMOTO, Izuru YAMAMOTO1995 Volume 20 Issue 1 Pages 49-56
Published: February 20, 1995
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSEffect of various ligands which include Imidacloprid related compounds, on the binding of [3H]phencyclidine (PCP) known as a probe for the allosteric site located in the receptor's ion channel and [3H]α-bungarotoxin (α-BGT) known as a probe for the acetylcholine (ACh) recognition site of the nicotinic acetylcholine receptor with its ion channel from the Torpedo electric organ, was examined. Nicotine and anabasine showed a strong agonistic action like carbachol and cytisine, whereas imidacloprid, 6-Cl-PMNI, acetamiprid, NMTHT, nitenpyram and MTENI were weakly agonistic. NMTHT, nitenpyram and MTENI were also noncompetitive blockers like coniine, DMPP, nereistoxin and d-tubocurarine which interacted with both the ACh recognition site and the allosteric site. PCP, TCP, ketamine, chlorpromazine and mecamylamine were noncompetitive blockers; also lobeline and trimethaphan were found to be noncompetitive blockers as against text books.View full abstractDownload PDF (974K) -
Motohiro TOMIZAWA, Hiroko OTSUKA, Toru MIYAMOTO, Mohyee E. ELDEFRAWI, ...1995 Volume 20 Issue 1 Pages 57-64
Published: February 20, 1995
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSUsing radioreceptor assay with [3H]α-bungarotoxin (α-BGT) and [3H]phencyclidine (PCP) as probes for the nicotinic acetylcholine receptor (nAChR) in membranes obtained from honeybee heads, the effects of various nAChR ligands, nicotinoids and neonicotinoids were studied. The data indicated differences in pharmacological characteristics between Torpedo electric organ and honeybee brain nAChRs. [3H]α-BGT binds to the acetylcholine (ACh) recognition site of the nAChRs of vertebrate skeletal muscle, Torpedo electric organ and honeybee brain. In vertebrates, [3H]PCP binds to an allosteric site on the receptor's ion channel and its binding is stimulated by receptor activation with agonists. However, the tested vertebrate cholinergic agonists inhibited [3H]α-BGT binding, but did not activate [3H]PCP binding to the honeybee nAChR. Saturation isotherms of the binding of [3H]α-BGT with or without PCP indicated that PCP interacted with the ACh recognition site on the nAChR. Furthermore, nicotine inhibited not only [3H]α-BGT binding but also [3H]PCP binding. Detailed study of [3H]PCP binding indicated that [3H]PCP bound to the honeybee brain membranes both at high and low affinity sites. The former corresponded to the vertebrate allosteric site on the nAChR and the latter to the ACh recognition site. Nicotine, anabasine and nitenpyram bound to both sites, while imidacloprid, 6-Cl-PMNI and acetamiprid bound selectively to the ACh recognition site. In houseflies, nicotine and imidacloprid produced excitation followed by paralysis, while PCP was anesthetic, even though PCP was as insecticidal as nicotine.View full abstractDownload PDF (1025K) -
Toshiyuki KATAGI, Masakazu MIYAKADO, Chiyozo TAKAYAMA, Shizuya TANAKA1995 Volume 20 Issue 1 Pages 65-74
Published: February 20, 1995
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSThe partition of organophosphorus pesticides in the multi-lamellar vesicles of dipalmitoyl L-α-phosphatidylcholine increased with their hydrophobicity and a dramatic change occurred with the phase transition of membranes. Both the incorporation of a double bond into the acyl chains of lipid and their shortening enhanced the partition, while the addition of a charge at the membrane surface greatly reduced the partition. The similar profiles were obtained for the corresponding oxon derivatives but in a smaller extent. Fluorescence polarization studies using neutral (DPH) and positively charged (tma-DPH) probes have shown that the partitioning site of pesticides in membranes changed with their hydrophobicity. Both partition and fluorescence studies have strongly suggested that organophosphorus pesticides possessing the P=S moiety are partitioned in the hydrophobic core of the lipid bilayer, while the oxon derivatives are in the hydrophilic region near the glycerol backbone of lipid.View full abstractDownload PDF (3317K) -
Inhibition of Housefly Glutathione S-Transferase by Chalcone and Comparison of Its Isozymes with RatToru MIYAMOTO, Izuru YAMAMOTO1995 Volume 20 Issue 1 Pages 75-82
Published: February 20, 1995
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESS2-, 3- and 4-Chloro-4′-phenylchalcones were weakly inhibitory against glutathione S-transferases (GST) from resistant (R) and susceptible (S) housefly abdomens. However, each of glutathione (GSH) conjugates of the above chalcones inhibited strongly both GSTs in an incompetitive fashion with respect to CDNB or DCNB. The inhibitory activity was in the order of 2-, 4- and 3-Chloro-compounds which was similar to the case of mouse liver GST. These facts indicated that the rate of GSH conjugation was slow in vitro insect system. On the other hand, the above chalcones increased the insecticidal activity of diazinon to R-fly in the order of 2-, 4- and 3-chloro-compounds. Diazinon is known to be more detoxified in R-fly than in S-fly by GST. Therefore, it is conceivable that such synergism is due to the conversion of the chalcones to the GSH conjugates by GST and the inhibition of GST by the conjugates, which decrease the detoxication of diazinon. There were differences between rat and housefly GSTs and between R- and S-fly GSTs. The affinity of CDNB was higher to R-fly GST than to S-fly GST, but both were far low as compared with the affinity to rat GST. On the other hand, the affinity of DCNB to GSTs was generally lower than that of CDNB and there was not so much difference between housefly and mouse or rat GSTs, although R-fly GST gave the lowest affinity. Comparison of subunits on sodium dodecylsulfate polyacrylamide gel electrophoresis suggested that fly GST was qualitatively different from rat GST. There was a minor difference between GSTs of R- and S-flies.View full abstractDownload PDF (996K) -
Yoshiaki KONO, Satoshi TAKEDA, Yukihiko KAMEDA, Masakazu TAKAHASHI, Ka ...1995 Volume 20 Issue 1 Pages 83-91
Published: February 20, 1995
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSInjection of trehalase inhibitor, validoxylamine A (VAA, 10μg/insect) evoked relaxation of segmental muscle and decrease of the pulsation of dorsal vessel in the final instar larvae of Mamestra brassicae. Ninety percent of the trehalase activity of the midgut was inhibited in a day. The larvae died afterward of incomplete pupation. We analysed the haemolymph components after the injection by 1H NMR and 13C NMR to elucidate the cause of the abnormality. Trehalose was actively synthesized from glucose regardless of VAA treatment and utilization of trehalose was suppressed by VAA. Trehalose concentration rose to 1.7 and 2.0 times of the control 1 and 3 days after injection respectively, and to 3.3 times at prepupal stage. Amino acid concentrations decreased once at the middle of the instar, but became at higher level than the control at prepupal stage. At this stage, phosphorylcholine level fell with increase of choline, and N-acetylglucosamine appeared. Accumulation of the components seemed to be caused by inhibition of the utilization of materials for pupal formation.View full abstractDownload PDF (994K) -
Nobuhito TSUCHISHITA1995 Volume 20 Issue 1 Pages 93-98
Published: February 20, 1995
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSDownload PDF (867K) -
Hidetaka HORI, Ryoichi SATO, Michio OHBA1995 Volume 20 Issue 1 Pages 99-107
Published: February 20, 1995
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSDownload PDF (5571K)
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