Ecdysteroid resistant subclones of the epithelial cell line from Chironomus Tentans (insecta, diptera). I. Selection and characterization of resistant clones

Spindler-Barth, Margarethe; Spindler, Klaus-Dieter

doi:10.1007/s11626-998-0093-y

Cited by 22 publications

(15 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mechanisms of resistance to ecdysone agonists have been described in several publications (Spindler-Barth and Spindler, 1998;Retnakaran et al, 2001;Hu et al, 2004). The agonists normally inhibit binding of [ 3 H]ponasterone A to the ecdysone receptor in agonist-treated cells (Nakagawa et al, 2002).…”

Section: Archives Of Insect Biochemistry and Physiologymentioning

confidence: 99%

Comparative larvicidal toxicities of three ecdysone agonists on the mosquitoes Aedes aegypti, Culex quinquefasciatus, and Anopheles gambiae

Beckage

Marion

Walton

et al. 2004

Arch Insect Biochem Physiol

View full text Add to dashboard Cite

Ecdysone agonists are hormonally active insect growth regulators that disrupt development of pest insects and have potential for development as insecticides. Their effects have been particularly well-studied in Lepidoptera and Coleoptera, but significantly less is known about their effects on dipterans, particularly aquatic species. The potency of three ecdysone agonists on larvae of 3 mosquito species, Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus, was examined. Anopheles gambiae was the most susceptible species and Ae. aegypti was the most resistant species to the effects of the three compounds tested. Potency, in descending order, was RH-2485 > RH-5992 > RH-5849. Dose-response relationships were determined for the three agonists; RH-2485 was found to be the most effective endocrine disruptor against all three species. The observed biological effects of these compounds were similar to those reported for other insects, and mosquitoes initiated molting and apolysis but did not complete a molt. In some cases, mosquito larvae synthesized a new cuticle that appeared to be normally sclerotized but the larvae failed to ecdyse and shed the exuvium. These compounds may prove to be valuable insect growth regulators for control of mosquitoes to decrease the frequency of pathogen transmission to humans. Prospects for using these compounds to control mosquitoes in the field are discussed, along with possible impacts on non-target arthropods in mosquito habitats.

show abstract

Section: Archives Of Insect Biochemistry and Physiologymentioning

confidence: 99%

Comparative larvicidal toxicities of three ecdysone agonists on the mosquitoes Aedes aegypti, Culex quinquefasciatus, and Anopheles gambiae

Beckage

Marion

Walton

et al. 2004

Arch Insect Biochem Physiol

View full text Add to dashboard Cite

show abstract

“…Enhanced metabolism of 20E is associated with hormone resistance in clones of the epithelial cell line from the dipteran C. dilutus, selected under the continuous presence of 20E (Kayser et al, 1997; Archives of Insect Biochemistry and Physiology January 2008 doi: 10.1002/arch. Spindler-Barth and Spindler, 1998). However, the latter authors suggested that such enzyme-based resistance mechanism may not be the primary cause of resistance but a consequence of other changes that happened somewhere in a regulatory pathway.…”

Section: Discussionmentioning

confidence: 99%

“…Wing (1988) also reported cross-resistance towards 20E and RH-5849 in the Kc D. melanogaster cells selected for resistance against both compounds. Spindler-Barth and Spindler (1998) reported that cells of C. dilutus selected in the presence of 20E were resistant only to the moulting hormone, but still responded to tebufenozide, whereas subclones selected in the presence of tebufenozide showed cross-resistance to 20E. Related to the in vivo system, some cross-resistance has been reported between dibenzoylhydrazinetype insecticides and other insecticides in many insects (Sauphanor and Bouvier, 1995;Wearing, 1998;Waldstein et al, 1999;Moulton et al, 2002;Smirle et al, 2002;Cao and Han, 2006).…”

Section: Discussionmentioning

confidence: 99%

Selection for resistance to methoxyfenozide and 20‐hydroxyecdysone in cells of the beet armyworm, Spodoptera exigua

Mosallanejad

Soin

Smagghe

2007

Arch Insect Biochem Physiol

View full text Add to dashboard Cite

In this report with an ecdysteroid-responsive cell line of the beet armyworm, Spodoptera exigua (Se4) selection for resistance against methoxyfenozide and the insect moulting hormone (20-hydroxyecdysone, 20E) was carried out to analyze the resulting resistant cells in order to elucidate possible mechanisms of resistance towards these compounds. From these cultures, five methoxyfenozide- and four 20E-resistant subclones were selected starting from 0.1 nM methoxyfenozide up to 100 microM and from 10 nM 20E up to 100 microM, respectively. To date, the selected cells kept their loss of susceptibility for 100 microM. Here we evaluated two processes known to be important in insecticide resistance, namely metabolism and pharmacokinetics, in the selected methoxyfenozide- and 20E-resistant subclones. Synergism experiments with piperonyl butoxide, S,S,S-tributyl phosphorotrithioate, and diethyl maleate, which are respective inhibitors of monooxygenases, esterases, and gluthation-S-transferases, did not affect the level of the resistance. To check the possible existence of active transport in the resistant cells, we used ouabain, an inhibitor of active membrane transport. In parallel, the absorption profile was studied in resistant and susceptible cells with use of 14C-methoxyfenozide. Interestingly, resistant subclones showed cross-resistance towards methoxyfenozide and 20E. The resistance was irreversible even after the compounds were removed from the medium.

show abstract

“…These subclones were constantly maintained in the presence of 1 pM 20-hydroxyecdysone but never experienced the analogue, except for those cells which were used to check periodically the resistance in hormone-free medium. Subclones ec.r.0, ec.r.1 and ec.r.2 were classified as resistant, and subclones s.6, s.9 and wild were sensitive to 20-hydroxyecdysone (Spindler-Barth and Spindler, 1997). Cells were washed twice with fresh medium and stored at -80°C until the enzyme assays.…”

Section: Methodsmentioning

confidence: 99%

“…Many of these cell lines express ecdysteroid receptors in reasonable density to account for their responsiveness to added steroid hormones. The epithelial cell line from the dipteran Chirorzornus tentaas has been well characterized with respect to morphological and biochemical changes that are triggered by the addition of ecdysteroids and non-steroidal analogues (Spindler-Barth and Spindler, 1997). After several years of culture in the presence of 20-hydroxyecdysone and the diacylhydrazine tebufenozide (RH-5992), various subclones could be selected expressing resistance to either the steroid, but responding to the analogue, or to both 20-hydroxyecdysone and tebufenozide (Spindler-Barth and Spindler, 1997).…”

mentioning

confidence: 99%

26‐Hydroxylation of Ecdysteroids is Catalyzed by a Typical Cytochrome P‐450‐Dependent Oxidase and Related to Ecdysteroid Resistance in an Insect Cell Line

Kayser¹,

Wtnkler²,

Spindler-Barth³

1997

European Journal of Biochemistry

Self Cite

View full text Add to dashboard Cite

The epithelial cell line from the dipteran Chironomus tentwzLy responds to the insect steroid hormone 20-hydroxyecdysone and the non-steroidal analogue tebufenozide by undergoing a morphogenetic and biochemical differentiation program. Long-term culture in the presence of 20-hydroxyecdysone has resulted in the selection of subclones that are resistant to the steroid but respond normally to the nonsteroidal analogue. In the present study, several subclones that were resistant to the steroid hormone have been compared with steroid-sensitive subclones with respect to their capability to metabolize 20-hydroxyecdysone. Homogenates of both types of cells, when incubated with 'H-labelled steroid in the presence of NADPH, produced 20,26-dihydroxyecdysone, which was further metabolized to two compounds, which behaved less polar than 20-hydroxyecdysone o n reverse-phase HPLC. Ecdysone, a lessactive hormone precursor, provided 26-hydroxyecdysone as the only product. The metabolites were identified by mass spectrometry coupled to HPLC, chromatography with authentic samples, and forination of acetonides. The structure of 20,26-dihydroxyecydsone was confirmed by 'H-NMR.The enzyme responsible for the synthesis of 20,26-dihydroxyecdysone in the Chirononius cell preparations has been characterized as a typical cytochrome P-450-dependent monooxygenase. It was a strictly microsomal enzyme, sensitive to inhibition by carbon monoxide and imidazole/triazole-based fungicides, and required NADPH for maximal activity. NADH could partly replace NADPH. The Michaelis constant ( K J for 20-hydroxyecdysone was 0.96 yM, and the maximal enzyme velocity (V,,,,,) was 50 pmol substrate metabolized . mg protein-' . min..'. 26-Hydroxylation of 20-hydroxyecdysone was inhibited by ecdysone, an alternative substrate, and by inokosterone, a product analogue, to 50% at 1.4 pM and 0.73 pM, respectively. When various subclones were compared with respect to their in vitro rate of 20-hydroxyecdysone metabolization, those clones known to be resistant to the steroid were 'high metabolizers' ( > 7 0 % relative rate), whereas the sensitive clones were 'poor metabolizers' (< 30% relative rate). Hence, it is tempting to conclude that ecdysteroid resistance of the Chiroricimu.s cell clones is due to metabolic inactivation of the steroid hormone.

show abstract

Ecdysteroid resistant subclones of the epithelial cell line from Chironomus Tentans (insecta, diptera). I. Selection and characterization of resistant clones

Cited by 22 publications

References 19 publications

Comparative larvicidal toxicities of three ecdysone agonists on the mosquitoes Aedes aegypti, Culex quinquefasciatus, and Anopheles gambiae

Comparative larvicidal toxicities of three ecdysone agonists on the mosquitoes Aedes aegypti, Culex quinquefasciatus, and Anopheles gambiae

Selection for resistance to methoxyfenozide and 20‐hydroxyecdysone in cells of the beet armyworm, Spodoptera exigua

26‐Hydroxylation of Ecdysteroids is Catalyzed by a Typical Cytochrome P‐450‐Dependent Oxidase and Related to Ecdysteroid Resistance in an Insect Cell Line

Contact Info

Product

Resources

About