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1.
新型二酰胺类杀虫剂对鱼尼丁受体作用的分子机理   总被引:16,自引:0,他引:16  
唐振华  陶黎明 《昆虫学报》2008,51(6):646-651
最近发现了一类新型二酰胺类杀虫剂——氟虫酰胺和氯虫酰胺,其作用靶标是鱼尼丁受体 (ryanodine receptors, RyRs)。本文对RyR的结构与功能、电压门控钙离子通道和鱼尼丁受体钙离子释放通道对细胞质钙离子内环境稳定的调节以及二酰胺类杀虫剂对RyRs作用的分子机理进行综述。二酰胺类杀虫剂使昆虫RyR通道处于持续的开放状态,引发钙离子从肌质网腔内大量释放,破坏了细胞质钙离子内环境的稳定,从而产生不同的药物学特性。这些变化都是由一个不同于鱼尼丁在RyR上的结合部位介导的。该类杀虫剂的作用对昆虫RyR s是高度专一的,结果产生选择毒性。由于二酰胺类杀虫剂的结构独特,作用方式新颖,对鳞翅目害虫效果好、杀虫谱广,对各种益虫和天敌安全,并对现用的杀虫剂无交互抗性,故它们非常适合于抗性治理和IPM。  相似文献   

2.
Insect ryanodine receptors: molecular targets for novel pest control chemicals   总被引:15,自引:0,他引:15  
Ryanodine receptors (RyRs) are a distinct class of ligand-gated calcium channels controlling the release of calcium from intracellular stores. They are located on the sarcoplasmic reticulum of muscle and the endoplasmic reticulum of neurons and many other cell types. Ryanodine, a plant alkaloid and an important ligand used to characterize and purify the receptor, has served as a natural botanical insecticide, but attempts to generate synthetic commercial analogues of ryanodine have proved unsuccessful. Recently two classes of synthetic chemicals have emerged resulting in commercial insecticides that target insect RyRs. The phthalic acid diamide class has yielded flubendiamide, the first synthetic ryanodine receptor insecticide to be commercialized. Shortly after the discovery of the phthalic diamides, the anthranilic diamides were discovered. This class has produced the insecticides Rynaxypyr(R) and Cyazypyrtrade mark. Here we review the structure and functions of insect RyRs and address the modes of action of phthalic acid diamides and anthranilic diamides on insect ryanodine receptors. Particularly intersting is the inherent selectivity both chemical classes exhibit for insect RyRs over their mammalian counterparts. The future prospects for RyRs as a commercially-validated target site for insect control chemicals are also considered.  相似文献   

3.
Anthranilic diamides, which include the new commercial insecticide, chlorantraniliprole, are an exciting new class of chemistry that target insect ryanodine receptors. These receptors regulate release of stored intracellular calcium and play a critical role in muscle contraction. As with insects, nematodes express ryanodine receptors and are sensitive to the plant alkaloid, ryanodine. However the plant parasitic nematode, Meloidogyne incognita, is insensitive to anthranilic diamides. Expression of a full-length Drosophila melanogaster ryanodine receptor in an insect cell line confers sensitivity to the receptor agents, caffeine and ryanodine along with nanomolar sensitivity to anthranilic diamides. Replacement of a 46 amino acid segment in a highly divergent region of the Drosophila C-terminus with that from Meloidogyne results in a functional RyR which lack sensitivity to diamide insecticides. These findings indicate that this region is critical to diamide sensitivity in insect ryanodine receptors. Furthermore, this region may contribute to our understanding of the differential selectivity diamides exhibit for insect over mammalian ryanodine receptors.  相似文献   

4.
Anthranilic diamide insecticide could control lepidopteran pests by selectively binding and activating insect ryanodine receptors (RyRs), and the unique mode of action is different from other conventional insecticides. In order to discover new anthranilic diamide insecticide as ryanodine receptors activators, a series of 11 novel anthranilic diamides derivatives (Ia-k) were synthesized and confirmed by melting point, 1H NMR, 13C NMR and elemental analyses. The preliminary bioactivity revealed that most title compounds showed moderate to remarkable activities against oriental armyworm (Mythimna separata) and diamondback moth (Plutella xylostella). Especially, compounds Ia and If, which exhibited 100% larvicidal activity against oriental armyworm at 1.0?mg?L?1, and comparable to that of chlorantraniliprole (100% at 1?mg?L?1). If displayed 60% insecticidal activity against diamondback moth at 0.01?mg?L?1, better than chlorantraniliprole (45% at 0.01?mg?L?1). The preliminary structure activity relationships were discussed. In addition, the calcium imaging experiment indicated that the insect ryanodine receptor is the potential target of If.  相似文献   

5.
Diamide insecticides selectively activate insect ryanodine receptors (RyRs), inducing uncontrolled release of calcium ions, and causing muscle contraction, paralysis and eventually death. The RyRG4946E substitution associated with diamide resistance has been identified in three lepidopteran pests, Plutella xylostella, Tuta absoluta and Chilo suppressalis. Recently, the T. absoluta RyRG4946V mutation was knocked into the model insect Drosophila melanogaster by CRISPR/Cas9 mediated genome editing and provided in vivo functional confirmation for its role in diamide resistance. In the present study, we successfully introduced the RyRG4946E mutation with CRISPR/Cas9 technology into a lepidopteran pest of global importance, Spodoptera exigua. The genome-edited strain (named 4946E) homozygous for the SeRyRG4946E mutation exhibited 223-, 336- and >1000-fold resistance to chlorantraniliprole, cyantraniliprole and flubendiamide, respectively when compared to the wild type strain (WHS) of S. exigua. Reciprocal crossing experiments revealed that the target-site resistance in strain 4946E underlies an autosomal and almost recessive mode of inheritance for anthranilic diamides, whereas it was completely recessive for flubendiamide. Our results not only provided in vivo functional validation of the RyRG4946E mutation in conferring high levels of resistance to diamide insecticides for the first time in a controlled genetic background of a lepidopteran pest, but also revealed slight differences on the level of resistance between anthranilic diamides (chlorantraniliprole and cyantraniliprole) and flubendiamide conferred by the SeRyRG4946E mutation.  相似文献   

6.
Wang J  Li Y  Han Z  Zhu Y  Xie Z  Wang J  Liu Y  Li X 《PloS one》2012,7(5):e36623
Ryanodine receptors (RyRs) are the targets of two novel classes of synthetic insecticidal chemicals, phthalic acid diamides and anthranilic diamides. Isolation of full-length RyR cDNAs is a critical step towards the structural and functional characterization of insect RyRs and an understanding of the molecular mechanisms underlying the species selective toxicity of diamide insecticides. However, there has been little research on the insect RyR genes due to the high molecular weight of the RyR proteins. In this study, we isolated a full-length RyR cDNA (named as CmRyR) from Cnaphalocrocis medinalis, an important rice pest throughout Southeast Asia. The composite CmRyR gene contains an ORF of 15264 bp encoding a protein of 5087 amino acid residues, which shares 79% overall identity with its Drosophila melanogaster homologue. All hallmarks of the RyR proteins are conserved in the CmRyR protein, suggesting that CmRyR is a structural and functional analogue of known RyRs. A multiple sequence alignment illustrates that the insect RyRs share high levels of amino acid sequence identity at the the COOH-terminal region. However, the amino acid residues analogous to the CmRyR residues N(4922), N(4924), N(4935), L(4950), L(4981), N(5013) and T(5064) are unique to lepidopteran RyRs compared with non-lepidopteran insect RyRs. This finding suggests that these residues may be involved in the differences in channel properties between lepidopteran and non-lepidopteran insect RyRs and in the species selective toxicity of diamide insecticides. Furthermore, two alternative splicing sites were identified in the CmRyR gene, one of which was located in the central part of the predicted second SPRY domain. Diagnostic PCR showed that the inclusion frequencies of two mutually exclusive exons (a/b) and one optional exon (c) differed between developmental stages or adult anatomical regions. Our results imply that alternative splicing may be a major means of generating functional diversity in C. medinalis RyR channel.  相似文献   

7.
Ryanodine receptors (RyRs) are a distinct class of ligand-gated channels controlling the release of calcium from intracellular stores. The emergence of diamide insecticides, which selectively target insect RyRs, has promoted the study of insect RyRs. In the present study, the full-length RyR cDNA (BdRyR) was cloned and characterized from the oriental fruit fly, Bactrocera dorsalis (Hendel), a serious pest of fruits and vegetables throughout East Asia and the Pacific Rim. The cDNA of BdRyR contains a 15,420-bp open reading frame encoding 5,140 amino acids with a predicted molecular weight of 582.4 kDa and an isoelectric point of 5.38. BdRyR shows a high level of amino acid sequence identity (78 to 97%) to other insect RyR isoforms. All common structural features of the RyRs are present in the BdRyR, including a well-conserved C-terminal domain containing consensus calcium-binding EF-hands and six transmembrane domains, and a large N-terminal domain. Quantitative real-time PCR analyses revealed that BdRyR was expressed at the lowest and highest levels in egg and adult, respectively, and that the BdRyR expression levels in the third instar larva, pupa and adult were 166.99-, 157.56- and 808.56-fold higher, respectively, than that in the egg. Among different adult body parts, the highest expression level was observed in the thorax compared with the head and abdomen. In addition, four alternative splice sites were identified in the BdRyR gene, with the first, ASI, being located in the central part of the predicted second spore lysis A/RyR domain. Diagnostic PCR analyses revealed that alternative splice variants were generated not only in a tissue-specific manner but also in a developmentally regulated manner. These results lay the foundation for further understanding the structural and functional properties of BdRyR, and the molecular mechanisms for target site resistance in B. dorsalis.  相似文献   

8.
Insect ryanodine receptors (RyRs) are the targets of diamide insecticides. Two point mutations G4946E and I4790M (numbering according to Plutella xylostella, PxRyR) in the transmembrane domain of the insect RyRs associated with diamide resistance have so far been identified in three lepidopteran pests, P. xylostella, Tuta absoluta and Chilo suppressalis. In this study, we identified one of the known RyR target site resistance mutations (I4790M) in a field‐collected population of Spodoptera exigua. The field‐collected WF population of S. exigua exhibited 154 fold resistance to chlorantraniliprole when compared with the susceptible WH‐S strain. Sequencing the transmembrane domains of S. exigua RyR (SeRyR) revealed that the resistant WF strain was homozygous for the I4743M mutation (corresponding to I4790M in PxRyR), whereas the G4900E allele (corresponding to G4946E of PxRyR) was not detected. The 4743M allele was introgressed into the susceptible WH‐S strain by crossing WF with WH‐S, followed by three rounds of backcrossing with WH‐S. The introgressed strain 4743M was homozygous for the mutant 4743M allele and shared about 94% of its genetic background with that of the recipient WH‐S strain. Compared with WH‐S, the near‐isogenic 4743M strain showed moderate levels of resistance to chlorantraniliprole (21 fold), cyantraniliprole (25 fold) and flubendiamide (22 fold), suggesting that the I4743M mutation confers medium levels of resistance to all three diamides. Genetic analysis showed diamide resistance in the 4743M strain was inherited as an autosomal and recessive trait. Results from this study have direct implications for the design of appropriate resistance monitoring and management practices to sustainably control S. exigua.  相似文献   

9.
Insect ryanodine receptors (RyR) are the molecular target-site for the recently introduced diamide insecticides. Diamides are particularly active on Lepidoptera pests, including tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae). High levels of diamide resistance were recently described in some European populations of T. absoluta, however, the mechanisms of resistance remained unknown. In this study the molecular basis of diamide resistance was investigated in a diamide resistant strain from Italy (IT-GELA-SD4), and additional resistant field populations collected in Greece, Spain and Brazil. The genetics of resistance was investigated by reciprocally crossing strain IT-GELA-SD4 with a susceptible strain and revealed an autosomal incompletely recessive mode of inheritance. To investigate the possible role of target-site mutations as known from diamondback moth (Plutella xylostella), we sequenced respective domains of the RyR gene of T. absoluta. Genotyping of individuals of IT-GELA-SD4 and field-collected strains showing different levels of diamide resistance revealed the presence of G4903E and I4746M RyR target-site mutations. These amino acid substitutions correspond to those recently described for diamide resistant diamondback moth, i.e. G4946E and I4790M. We also detected two novel mutations, G4903V and I4746T, in some of the resistant T. absoluta strains. Radioligand binding studies with thoracic membrane preparations of the IT-GELA-SD4 strain provided functional evidence that these mutations alter the affinity of the RyR to diamides. In combination with previous work on P. xylostella our study highlights the importance of position G4903 (G4946 in P. xylostella) of the insect RyR in defining sensitivity to diamides. The discovery of diamide resistance mutations in T. absoluta populations of diverse geographic origin has serious implications for the efficacy of diamides under applied conditions. The implementation of appropriate resistance management strategies is strongly advised to delay the further spread of resistance.  相似文献   

10.
Diamide insecticides are used widely against lepidopteran pests, acting as potent activators of insect Ryanodine Receptors (RyRs) and thus inducing muscle contraction and eventually death. However, resistant phenotypes have recently evolved in the field, associated with the emergence of target site resistance mutations (G4946E/V and I4790M). We investigated the frequency of the mutations found in a resistant population of Tuta absoluta from Greece (G4946V ~79% and I4790M ~21%) and the associated diamide resistance profile: there are very high levels of resistance against chlorantraniliprole (9329-fold) and flubendiamide (4969-fold), but moderate levels against cyantraniliprole (191-fold). To further investigate functionally the contribution of each mutation in the resistant phenotype, we used CRISPR/Cas9 to generate genome modified Drosophila carrying alternative allele combinations, and performed toxicity bioassays against all three diamides. Genome modified flies bearing the G4946V mutation exhibited high resistance ratios to flubendiamide (91.3-fold) and chlorantraniliprole (194.7-fold) when compared to cyantraniliprole (5.4-fold). Flies naturally wildtype for the I4790M mutation were moderately resistant to flubendiamide (15.3-fold) but significantly less resistant to chlorantraniliprole (7.5-fold), and cyantraniliprole (2.3-fold). These findings provide in vivo functional genetic confirmation for the role and relative contribution of RyR mutations in diamide resistance and suggest that the mutations confer subtle differences on the relative binding affinities of the three diamides at an overlapping binding site on the RyR protein.  相似文献   

11.
In this study, we report a novel cellulase [β-1,4-endoglucanase (EGase), EC 3.2.1.4] cDNA (Bh-EGase II) belonging to the glycoside hydrolase family (GHF) 45 from the beetle Batocera horsfieldi. The Bh-EGase II gene spans 720 bp and consists of a single exon coding for 239 amino acid residues. Bh-EGase II showed 93.72% protein sequence identity to Ag-EGase II from the beetle Apriona germari. The GHF 45 catalytic site is conserved in Bh-EGase II. Bh-EGase II has three putative N-glycosylation sites at 56–58 (N–K–S), 99–101 (N–S–T), and 237–239 (N–Y–S), respectively. The cDNA encoding Bh-EGase II was expressed in baculovirus-infected insect BmN cells and Bombyx mori larvae. Recombinant Bh-EGase II from BmN cells and larval hemolymph had an enzymatic activity of approximately 928 U/mg. The enzymatic catalysis of recombinant Bh-EGase II showed the highest activity at 50 °C and pH 6.0.  相似文献   

12.
The diamondback moth (Plutella xylostella) is a globally distributed and important economic pest, and it has developed resistance to all conventional insecticide classes used in the field. Chlorantraniliprole is a new chemical class of insecticide that acts as a conformation‐sensitive activator of the insect ryanodine receptor (RyR). In the present study, a field strain (16.3‐fold resistance to chlorantraniliprole) was collected in Korea and lab‐selected with chlorantraniliprole for more than one year. The resulting strain presented 2,157‐fold resistance to chlorantraniliprole. A point mutation (G4946E) in the RyR gene was observed at a high frequency in the resistant strain. Enzyme assays indicated that glutathione S‐transferase (GST) and P450 activity in the resistant strain were 2.4‐ and 1.96‐times higher than that of the susceptible strain, respectively. The expression of the RyR, GST (sigma, omega, and zeta) and CYP321E1 gene was higher in the resistant strain than in the susceptible strain. The F1 progeny resulting from reciprocal crosses did not reveal maternal effects or a diamide‐susceptible phenotype, which suggests an autosomal nearly recessive mode of inheritance. In addition, we surveyed the susceptibility to 13 insecticides (3 diamides, 2 synthetic pyrethroids, 2 spinosyns, 1 organophosphate, 1 oxadiazine, 1 avermectin, and 3 others) in the chlorantraniliprole‐resistant strain. The resistant strain exhibited high cross‐resistance to flubendiamide (5,910 fold) and showed no cross‐resistance to spinetoram, spinosad, indoxacarb, and metaflumizone. These results can serve as an important basis for guiding the use of insecticides in the field.  相似文献   

13.
Anthranilic diamides and flubendiamide belong to a new chemical class of insecticides acting as conformation sensitive activators of the insect ryanodine receptor (RyR). These compounds control a diverse range of different herbivorous insects including diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), a notorious global pest on cruciferous crops, which recently developed resistance due to target-site mutations located in the trans-membrane domain of the Plutella RyR. In the present study we further investigated the genetics and functional implications of a RyR G4946E target-site mutation we recently identified in a Philippine diamondback moth strain (Sudlon). Strain Sudlon is homozygous for the G4946E mutation and has been maintained under laboratory conditions without selection pressure for almost four years, and still exhibit stable resistance ratios of >2000-fold to all commercial diamides. Its F1 progeny resulting from reciprocal crosses with a susceptible strain (BCS-S) revealed no maternal effects and a diamide susceptible phenotype, suggesting an autosomally almost recessive mode of inheritance. Subsequent back-crosses indicate a near monogenic nature of the diamide resistance in strain Sudlon. Radioligand binding studies with Plutella thoracic microsomal membrane preparations provided direct evidence for the dramatic functional implications of the RyR G4946E mutation on both diamide specific binding and its concentration dependent modulation of [3H]ryanodine binding. Computational modelling based on a cryo-EM structure of rabbit RyR1 suggests that Plutella G4946E is located in trans-membrane helix S4 close to S4–S5 linker domain supposed to be involved in the modulation of the voltage sensor, and another recently described mutation, I4790M in helix S2 approx. 13 Å opposite of G4946E. Genotyping by pyrosequencing revealed the presence of the RyR G4946E mutation in larvae collected in 2013/14 in regions of ten different countries where diamide insecticides largely failed to control diamondback moth populations. Thus, our study highlights the global importance of the G4946E RyR target-site mutation, which as a mechanism on its own, confers high-level resistance to diamide insecticides in diamondback moth.  相似文献   

14.
15.
Arylalkylamine N-acetyltransferase (AANAT; EC 2.3.1.87) catalyzes the N-acetylation of arylalkylamines. A cDNA encoding AANAT (ApAANAT) was cloned from Antheraea pernyi by PCR. The cDNA of 1966 bp encodes a 261 amino acid protein. The amino acid sequence was found to have a high homology with Bombyx mori AANAT (BmNAT) but had very low homology with vertebrate AANATs. Amino acid sequence analysis revealed that four insect AANATs cloned from three species including ApAANAT formed a distinct cluster from the vertebrate group. A recombinant ApAANAT protein was expressed in Sf9 cells using a baculovirus expression system, having AANAT activity. The transformed cell extract acetylated tryptamine, serotonin, dopamine, tyramine, octopamine and norepinephrine. The AANAT activity was inhibited at over 0.03 mM tryptamine. Although insect AANATs have been considered as a target of insecticide, this type of insecticide has never been developed. Screening a chemical library of Otsuka Chemical Co., Ltd., we found a novel compound and its derivatives that inhibited the AANAT activity of ApAANAT. This may facilitate investigation of the monoamine metabolic pathway in insects and the development of new types of insecticides and inhibitors of AANATs.  相似文献   

16.
Diamide insecticides such as chlorantraniliprole and flubendiamide are a new class of insecticide that selectively target insect ryanodine receptors (RyR), a distinct class of homo-tetrameric calcium release channels which play a pivotal role in calcium homeostasis in numerous cell types. Resistance to these insecticides has recently been reported in the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), a global lepidopteran pest of cruciferous crops. In the present study a region of the gene encoding the proposed diamide binding site of the RyR from P. xylostella collected from the Philippines and Thailand and found to be over 200-fold resistant to both chlorantraniliprole and flubendiamide compared to susceptible strains, were amplified by RT-PCR and sequenced. Comparison of the sequence with those from several susceptible reference strains revealed non-synonymous mutations in each of the resistant strains that in both cases lead to a glycine to glutamic acid substitution (G4946E) in the protein. The independent evolution of the same amino acid substitution within a highly conserved region of the proposed diamide binding site in two geographically separated resistant strains of P. xylostella strongly suggests a causal association with diamide resistance. Furthermore we designed a pyrosequencing-based diagnostic assay for resistance monitoring purposes that can be used to detect the G4946E mutation in field-collected samples of diamondback moth. The implications of the reported findings for resistance management strategies are discussed.  相似文献   

17.
18.
Wenjun Zheng  Zheng Liu 《Proteins》2017,85(9):1633-1644
The ryanodine receptors (RyR) are essential to calcium signaling in striated muscles, and numerous disease mutations have been identified in two RyR isoforms, RyR1 in skeletal muscle and RyR2 in cardiac muscle. A deep understanding of the activation/regulation mechanisms of RyRs has been hampered by the shortage of high‐resolution structures and dynamic information for this giant tetrameric complex in different functional states. Toward elucidating the molecular mechanisms of disease mutations in RyRs, we performed molecular dynamics simulation of the N‐terminal domain (NTD) which is not only the best‐resolved structural component of RyRs, but also a hotspot of disease mutations. First, we simulated the tetrameric NTD of wild‐type RyR1 and three disease mutants (K155E, R157Q, and R164Q) that perturb the inter‐subunit interfaces. Our simulations identified a dynamic network of salt bridges involving charged residues at the inter‐subunit/subdomain interfaces and disease‐mutation sites. By perturbing this key network, the above three mutations result in greater flexibility with the highest inter‐subunit opening probability for R157Q. Next, we simulated the monomeric NTD of RyR2 in the presence or absence of a central Cl anion which is known to stabilize the interfaces between the three NTD subdomains (A, B, and C). We found that the loss of Cl restructures the salt‐bridge network near the Cl‐binding site, leading to rotations of subdomain A/B relative to subdomain C and enhanced mobility between the subdomains. This finding supports a mechanism for disease mutations in the NTD of RyR2 via perturbation of the Cl binding. The rich structural and dynamic information gained from this study will guide future mutational and functional studies of the NTD of RyRs. Proteins 2017; 85:1633–1644. © 2017 Wiley Periodicals, Inc.  相似文献   

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20.
Currently, there is a strong trend towards increasing insecticide-based vector control coverage in malaria endemic countries. The ecological consequence of insecticide applications has been mainly studied regarding the selection of resistance mechanisms; however, little is known about their impact on vector competence in mosquitoes responsible for malaria transmission. As they have limited toxicity to mosquitoes owing to the selection of resistance mechanisms, insecticides may also interact with pathogens developing in mosquitoes. In this study, we explored the impact of insecticide exposure on Plasmodium falciparum development in insecticide-resistant colonies of Anopheles gambiae s.s., homozygous for the ace-1 G119S mutation (Acerkis) or the kdr L1014F mutation (Kdrkis). Exposure to bendiocarb insecticide reduced the prevalence and intensity of P. falciparum oocysts developing in the infected midgut of the Acerkis strain, whereas exposure to dichlorodiphenyltrichloroethane reduced only the prevalence of P. falciparum infection in the Kdrkis strain. Thus, insecticide resistance leads to a selective pressure of insecticides on Plasmodium parasites, providing, to our knowledge, the first evidence of genotype by environment interactions on vector competence in a natural Anopheles–Plasmodium combination. Insecticide applications would affect the transmission of malaria in spite of resistance and would reduce to some degree the impact of insecticide resistance on malaria control interventions.  相似文献   

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