Comparative ecdysteroid action of ring‐substituted dibenzoylhydrazines in Spodoptera exigua

Smagghe, Guy; Nakagawa, Yoshiaki; Carton, Bert; Mourad, A K; Fujita, Toshio; Tirry, Luc

doi:10.1002/(sici)1520-6327(1999)41:1<42::aid-arch7>3.3.co;2-8

Cited by 11 publications

(27 citation statements)

References 27 publications

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“…This may be because of the facile oxidation of the sulfide moiety to sulfone/sulfoxide through metabolism. We reported that RH-5849 was 10-fold less toxic than tebufenozide against Lepidopteran C. suppressalis (Pyralidae; pLD50 = 6.27 vs. 7.32) and 100-fold less toxic than tebufenozide against S. exigua (Noctuidae; pLD50 = 4.91 vs. 7.06) [40]. The difference in pLD50 values between RH-5849 and tebufenozide was 100-fold against S. litura (Noctuidae), which is consistent with the toxicity results for S. exigua.…”

Section: Discussionmentioning

confidence: 99%

Structure–activity relationship of imidazothiadiazole analogs for the binding to the ecdysone receptor of insect cells

Yokoi¹,

Minami²,

Nakagawa³

et al. 2015

Pesticide Biochemistry and Physiology

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Diacylhydrazines are the first non-steroidal ecdysone agonists, and five compounds are used as insecticides in agriculture. After the discovery of diacylhydrazine-type compounds, numerous non-steroidal structures were reported as ecdysone agonists. Among various ecdysone agonists, imidazothiadiazoles are reported to be very potent in vitro; however, the experimental detail for the structure identification and bioassays are not stated in the paper (Holmwood and Schindler, Bioorg. Med. Chem. 17, 4064-4070, 2009). In our present study, we synthesized 18 imidazothiadiazole-type compounds and confirmed the chemical structures by spectrometric analyses. The binding activity of the synthesized compounds to the ecdysone receptor was evaluated in terms of the concentration required for 50% inhibition of [(3)H]ponasterone A incorporation [IC50 (M)] into lepidopteran (Sf-9), coleopteran (BCRL-Lepd-SL1), and dipteran (NIAS-AeAl2) cells. 6-(2-Chlorophenyl)-2-(trifluoromethyl)imidazo[2,1-b] [1,3,4]-thiadiazol-5-yl)acrylamide analogs with CONHR (secondary amide) were very potent against Sf-9 cells, but further alkylation (tertiary amide: CONR2) decreased the activity dramatically. Additionally, a primary amide analog (CONH2) was inactive. The activity also decreased 150-fold by the saturation of olefin region of the acrylamide moiety. In addition, various substituents were introduced at the 2-position of the imidazothiadiazole ring to disclose the physicochemical properties of the substituents which are important for receptor binding. The activity increased by 7500-fold with the introduction of the CF2CF2CF3 group compared to the unsubstituted compound against Sf-9 cells. Quantitative structure-activity relationship analysis for these substituents indicated that hydrophobic and electron-withdrawing groups were favorable for binding. Some of the compounds with strong receptor binding activity showed good larvicidal activity against Spodoptera litura. In contrast, the binding affinity of imidazothiadiazole analogs was low or not observed against dipteran and coleopteran cells.

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Section: Discussionmentioning

confidence: 99%

Structure–activity relationship of imidazothiadiazole analogs for the binding to the ecdysone receptor of insect cells

Yokoi¹,

Minami²,

Nakagawa³

et al. 2015

Pesticide Biochemistry and Physiology

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“…Previously, RH-2485 was found to have a high accumulation rate in target cells and high binding affinity to ecdysteroid receptors in Lepidoptera compared with ecdysteroids (Yund and Osterbur, 1985;Smagghe et al, 1999Smagghe et al, , 2001a.…”

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confidence: 99%

Effects of a Fat Body Extract on Larval Midgut Cells and Growth of Lepidoptera

Smagghe¹,

Elsen²,

Loeb³

et al. 2003

In Vitro Cell. Dev. Biol. - Animal

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SUMMARYTreatment with fat body extract (FBX) from pupae of the tobacco hornworm, Manduca sexta, caused mortality in larvae of two pest lepidopterans, the gypsy moth, Lymantria dispar, and the cotton leafworm, Spodoptera littoralis. In FBXtreated larvae, the feeding rate was depressed, causing reduced weight gain and then larval death. Their midgut showed formation of multicellular layers of midgut epidermis, indicating stem-cell hyperplasia. Hence, the integument of FBXtreated larvae had a double cuticle, indicating induction of premature molting. But radioimmunoassay measurements confirmed that the amount of ecdysteroids in FBX was too low to be responsible for the molt-inducing effects observed after treatment with FBX. With midgut stem cell cultures in vitro, addition of FBX to the culture medium stimulated cell proliferation and differentiation in a concentration-dependent manner. This effect was compared with those of insect molting hormones, ecdysone and 20-hydroxyecdysone; an ecdysteroid agonist, RH-2485; and a purified protein from FBX (multiplication factor). This article describes the mode of action of FBX and possible interplay between fat body factor(s) and insect hormones in the development and metamorphosis of the insect midgut.Key words: midgut stem cells; 20-hydroxyecdysone; metamorphosis; hyperplasia; Lymantria dispar; Spodoptera littoralis.In insects, growth and metamorphosis are governed largely by hormones and growth factors. When these bind to their specific receptors, changes such as cell division, differentiation, tissue repair, chemotaxis, cell death, and other processes are regulated (Hogan et al., 1994;Slack, 2000). Insect molting hormones, the ecdysteroids, induce metamorphosis in vivo and in vitro (Oberlander and Fulco, 1967; Akai, 1976; Riddiford, 1985;Smagghe et al., 1996), and insect growth factors also regulate insect development (reviewed by Loeb et al., 1999;Homma et al., 2001). The physiologically active molting hormone in most insects is 20-hydroxyecdysone (20E). However, products of fat body tissue also play a role in insect development. Oberlander and Tomblin (1972) and Benson et al. (1974) reported that a fat body component stimulated the development of lepidopteran imaginal disks cultured in medium containing 20E and fat body. Loeb and Hakim (1991) and Loeb (1994) reported that an aqueous extract of isolated fat body (FBX) from abdomens of newly ecdysed pupae of the tobacco hornworm, Manduca sexta, played a role in the initiation of meiosis in cultured sperm of the boll worm, Heliothis virescens (Giebultowicz et al., 1987), promoted growth and development of the male genital tract in H. virescens and the gypsy moth, Lymantria dispar, in vitro (Loeb and Hakim, 1991), and induced mitosis in cultured midgut cells of M. sexta (Sadrud-din et al., 1994) and H. virescens (Loeb andHakim, 1996). FBX also increased the growth-stimulatory effect of 20E 1 To whom correspondence should be addressed at E-mail: guy. smagghe@rug.ac.be in vitro on imaginal wing disks of another lepidoptera...

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“…Methoxyfenozide (RH-2485) is the latest compound in this class to be developed commercially and is the most potent analog to date against larval Lepidoptera (Ishaaya et al 1995;Le et al 1996;Trisyono and Chippendale 1997;Smagghe et al 1998bSmagghe et al , 1999. The Þrst sales of methoxyfenozide occurred in 1999, and the Þrst full registrations in the United States were granted for cotton and pome fruits in 2000.…”

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Pro-active Management of Beet Armyworm (Lepidoptera: Noctuidae) Resistance to Tebufenozide and Methoxyfenozide: Baseline Monitoring, Risk Assessment, and Isolation of Resistance

Moulton¹,

Pepper²,

Jansson³

et al. 2002

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Susceptibility to tebufenozide and methoxyfenozide of beet armyworm [Spodoptera exigua (Hübner)] from the southern United States and Thailand was determined through exposure of first and third instars to dipped cotton leaves. Among the field populations evaluated, tebufenozide LC50 values for first and third instars, respectively, ranged from 0.377 to 4.41 and 4.37-46.6 microg (AI) /ml of solution. Methoxyfenozide LC50 values for first and third instars of field populations ranged from 0.058 to 0.487 and 0.601-3.83 microg (AI)/ml of solution. A Thailand field strain exhibiting reduced susceptibility to both compounds was subjected to intense laboratory selection for three nonconsecutive generations. At the LC50 and LC90, selected Thailand strains were 45-68 times and 150-1,500 times less susceptible to tebufenozide and 340-320 times and 120-67 times less susceptible to methoxyfenozide as first and third instars, respectively, when compared with the laboratory reference strain. Among the U.S. field populations evaluated, ones from Belle Glade, FL, and Florence, SC, were generally the most susceptible and ones from Maricopa and Parker, AZ, were the least susceptible. Selection of the Thailand field strain with tebufenozide reduced susceptibility to both compounds, and selection of Thailand strains previously pressured with either compound further reduced susceptibility to both, suggesting at least some commonality of resistance mechanism. Characterization of this resistance will provide information that will be helpful for pro-active management of resistance for this valuable group of insecticides.

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Comparative ecdysteroid action of ring‐substituted dibenzoylhydrazines in Spodoptera exigua

Cited by 11 publications

References 27 publications

Structure–activity relationship of imidazothiadiazole analogs for the binding to the ecdysone receptor of insect cells

Structure–activity relationship of imidazothiadiazole analogs for the binding to the ecdysone receptor of insect cells

Effects of a Fat Body Extract on Larval Midgut Cells and Growth of Lepidoptera

Pro-active Management of Beet Armyworm (Lepidoptera: Noctuidae) Resistance to Tebufenozide and Methoxyfenozide: Baseline Monitoring, Risk Assessment, and Isolation of Resistance

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