| nuclear polyhedrosis virus replication in permanent cell lines of the cabbage moth (mamestra brassicae l.). | | 1976 | 787805 |
| processing of delta-endotoxin from bacillus thuringiensis subsp. kurstaki hd-1 and hd-73 by gut juices of various insect larvae. | midgut juices were prepared from adoxophyes sp., smaller tea tortrix (stt); bombyx mori, silkworm (sw); spodoptera litura, common cutworm (ccw); plutella xylostella, diamondback moth (dbm); and musca domestica, housefly (hf) and immobilized onto sepharose 4b. delta-endotoxins (icps) from bacillus thuringiensis subsp. kurstaki hd-1 and hd-73 were digested by these immobilized gut juice proteases. all gut juices tested derived relatively proteolytic resistant cores from icp. the molecular sizes of ... | 1992 | 1328398 |
| construction of chimeric insecticidal proteins between the 130-kda and 135-kda proteins of bacillus thuringiensis subsp. aizawai for analysis of structure-function relationship. | eight chimeric insecticidal protein (ip) genes were constructed between the 130-kda and 135-kda ip genes of bacillus thuringiensis subsp. aizawai, and expressed in escherichia coli jm103 cells. the characterization of the produced chimeric ips indicated that the variable region (vr1) in the amino-terminal half of the ips is responsible for the insecticidal activity against larvae of spodoptera litura and plutella xylostella. the carboxy-terminal half of vr1 was important for the formation of the ... | 1990 | 1368534 |
| insecticidal toxins from bacillus thuringiensis subsp. kenyae: gene cloning and characterization and comparison with b. thuringiensis subsp. kurstaki cryia(c) toxins. | genes encoding insecticidal crystal proteins were cloned from three strains of bacillus thuringiensis subsp. kenyae and two strains of b. thuringiensis subsp. kurstaki. characterization of the b. thuringiensis subsp. kenyae toxin genes showed that they are most closely related to cryia(c) from b. thuringiensis subsp. kurstaki. the cloned genes were introduced into bacillus host strains, and the spectra of insecticidal activities of each cry protein were determined for six pest lepidopteran insec ... | 1991 | 2014985 |
| resistance to the bacillus thuringiensis bioinsecticide in a field population of plutella xylostella is due to a change in a midgut membrane receptor. | the biochemical mechanism for resistance to bacillus thuringiensis crystal proteins was studied in a field population of diamondback moths (plutella xylostella) with a reduced susceptibility to the bioinsecticidal spray. the toxicity and binding characteristics of three crystal proteins [cryia(b), cryib, and cryic] were compared between the field population and a laboratory strain. the field population proved resistant (greater than 200-fold compared with the laboratory strain) to cryia(b), one ... | 1991 | 2052591 |
| [identification of nuclear polyhedrosis viruses by restriction analysis]. | the restriction endonucleases bam hi, pst i, sla i were used to study dna of nuclear polyhedrosis virus (npv) of bollworm, two npv isolates of cabbage moth, npv of black arches moth isolated from a natural population of caterpillars. the mean molecular sizes of virus genomes were calculated. genotypic differences between two isolates of cabbage moth npv were demonstrated. heterogeneity of a natural isolate of black arches moth npv was established. | 1990 | 2082555 |
| activation of insect cell adenylate cyclase by bacillus thuringiensis delta-endotoxins and melittin. toxicity is independent of cyclic amp. | insecticidal bacillus thuringiensis (bt) delta-endotoxins are cytolytic to a range of insect cell lines in vitro. addition of bt var. aizawai or var. israelensis toxins to mamestra brassicae (cabbage moth) cells in vitro increased intracellular cyclic amp, which was paralleled by activation of adenylate cyclase in isolated membranes. var. kurstaki toxin, which does not lyse m. brassicae cells, had no effect on cyclic amp concentrations in intact cells, but was able to stimulate adenylate cyclase ... | 1988 | 2844167 |
| in vivo mass production in the cabbage moth (mamestra brassicae) of a heterologous (panolis) and a homologous (mamestra) nuclear polyhedrosis virus. | in preparation for field trials, a nuclear polyhedrosis virus (npv) of the pine beauty moth, panolis flammea, was mass produced in vivo in an alternative (heterologous) host, the cabbage moth, mamestra brassicae. simultaneously, mamestra npv was also produced in m. brassicae. this homologous npv/host system was a consistently more efficient production system than the heterologous one. evidence is presented that increased humidity may improve levels of infection and, therefore, yield achieved. fu ... | 1988 | 3286670 |
| the process of virus assembly in insect virus mixed infections. | interference occurred upon infection of the cabbage moth caterpillars (mamestra brassicae l.) with a mixture of nuclear polyhedrosis virus (npv) and cytoplasmic polyhedrosis virus (cpv), resulting in the impairment of virus assembly, and formation of abnormal nucleocapsids. at the same time protein supercapsids were produced normally, but contained no infectious virions. when insects were infected with related viruses, the virions developed as usual, but the protein supercapsids revealed abnorma ... | 1983 | 6139945 |
| morphogenesis of nuclear polyhedrosis virus from autographa californica in a cell line from mamestra brassicae (cabbage moth). further aspects on baculovirus assembly. | cultures of cell line izd-mb 0503 from mamestra brassicae were inoculated with nonoccluded nuclear polyhedrosis virus of autographa californica (acnov). at 1 h postinoculation (p.i.) nucleocapsids were found in the cytoplasm near nuclear pores and within the nucleoplasm. formation of virogenic stroma was observed at 7 h p.i. the first short empty capsids were seen at 10 h postinoculation (p.i.), followed by partially and completely filled nucleocapsids (11-12 h p.i.) with most capsids filled at ... | 1983 | 6339063 |
| growth of nuclear polyhedrosis virus in larvae of the cabbage moth, mamestra brassicae l. | growth of nuclear polyhedrosis virus (npv) in 5 larval instars of cabbage moth, mamestra brassicae, has been quantified using 2 methods. numbers of polyhedra were estimated by light microscope counts while concentrations of virus protein antigen were estimated using elisa. virus growth was rapid initially but slowed during its later stages, although elisa protein concentrations decreased once a peak had been reached. there was a linear correlation between polyhedral counts and virus protein duri ... | 1981 | 7034687 |
| immunohistochemical detection of binding of cryia crystal proteins of bacillus thuringiensis in highly resistant strains of plutella xylostella (l.) from hawaii. | we detected binding of insecticidal crystal proteins from bacillus thuringiensis in one susceptible strain and six resistant strains of diamondback moth, plutella xylostella, from hawaii. immunohistochemical tests with tissue sections from larval midguts showed specific binding of cryia(a), cryia(b), and cryia(c) to brush border membranes. cryie, which is not toxic to p. xylostella, did not bind to midgut tissues. larvae from one of the resistant strains ingested extremely high concentrations of ... | 1995 | 7626052 |
| toxicity of microcystin-lr, isolated from microcystis aeruginosa, against various insect species. | microcystin-lr (mc-lr), isolated from the cyanobacterium microcystis aeruginosa kuetzing emend. elenkin strain ccap 1450/4 was tested for biological activity against four species of insect and the invertebrate artemia salina. the efficacy of pesticidal activity was compared with various insecticides. the 24 hr ld50 value for third instar diamond-backed moth, plutella xylostella, on ingestion from a treated leaf surface was 1.0 micrograms cm2, compared with a 72 hr ld50 value for rotenone of 2.0 ... | 1995 | 7676468 |
| kinetics of bacillus thuringiensis toxin binding with brush border membrane vesicles from susceptible and resistant larvae of plutella xylostella. | an optical biosensor technology based on surface plasmon resonance was used to determine the kinetic rate constants for interactions between the cryia(c) toxin from bacillus thuringiensis and brush border membrane vesicles purified from susceptible and resistant larvae of diamondback moth (plutella xylostella). cryia(c) association and dissociation rate constants for vesicles from susceptible larvae were determined to be 4.5 x 10(3) m-1 s-1 and 3.2 x 10(-5) s-1, respectively, resulting in a calc ... | 1995 | 7744839 |
| distribution of cryv-type insecticidal protein genes in bacillus thuringiensis and cloning of cryv-type genes from bacillus thuringiensis subsp. kurstaki and bacillus thuringiensis subsp. entomocidus. | dna dot blot hybridizations with a cryv-specific probe and a cryi-specific probe were performed to screen 24 bacillus thuringiensis strains for their cryv-type (lepidopteran- and coleopteran-specific) and cryi-type (lepidopteran-specific) insecticidal crystal protein gene contents, respectively. the cryv-specific probe hybridized to 12 of the b. thuringiensis strains examined. most of the cryv-positive strains also hybridized to the cryi-specific probe, indicating that the cryv genes are closely ... | 1995 | 7793960 |
| a comparative study of effects of atrazine on xenobiotic metabolizing enzymes in fish and insect, and of the in vitro phase ii atrazine metabolism in some fish, insects, mammals and one plant species. | 1. atrazine (3 daily i.p. doses of 0.20 mg/kg or 10 ppb in the water for 14 days) did not change the xenobiotic metabolizing enzyme activities (xme) towards the substrates aldrin epoxidase (ae), nadph-cytochrome c reductase (nccr), 7-ethoxyresorufin o-deethylase (erod), 1-chloro-2,4-dinitro-benzene (cdnb) and 1,2-dichloro-4-nitrobenzene (dcnb) in trout liver (oncorhynchus mykiss) compared to the controls. 2. various treatment regimens of atrazine in a semisynthetic diet changed the xme activitie ... | 1993 | 7903609 |
| reversal of resistance to bacillus thuringiensis in plutella xylostella. | continued success of the most widely used biopesticide, bacillus thuringiensis, is threatened by development of resistance in pests. experiments with plutella xylostella (diamondback moth), the first insect with field populations resistant to b. thuringiensis, revealed factors that promote reversal of resistance. in strains of p. xylostella with 25- to 2800-fold resistance to b. thuringiensis compared with unselected strains, reversal of resistance occurred when exposure to b. thuringiensis was ... | 1994 | 8183881 |
| a bacillus thuringiensis insecticidal crystal protein with a high activity against members of the family noctuidae. | the full characterization of a novel insecticidal crystal protein, named cry9ca1 according to the revised nomenclature for cry proteins, from bacillus thuringiensis serovar tolworthi is reported. the crystal protein has 1,157 amino acids and a molecular mass of 129.8 kda. it has the typical features of the lepidoptera-active crystal proteins such as five conserved sequence blocks. also, it is truncated upon trypsin digestion to a toxic fragment of 68.7 kda by removal of 43 amino acids at the n t ... | 1996 | 8572715 |
| replication of a mamestra brassicae nuclear polyhedrosis virus in a newly established mamestra brassicae cell line. | a continuous cell line, designated mbl-3, was newly established from minced neonate larvae of the cabbage armyworm, mamestra brassicae. this new cell line is heteroploid, containing triploid cells predominantly at the frequency of about 50%. doubling time of the cell population is 33 hrs. the akutsu isolate of a mamestra brassicae nuclear polyhedrosis virus (mbnpv) was examined for replication in 16 continuous cell lines, including the cell line mbl-3, from seven lepidoptera species: mamestra br ... | 1995 | 8578995 |
| cloning of a novel crystal protein gene cry1k from bacillus thuringiensis subsp. morrisoni. | a novel crystal protein gene cry1k has been cloned and sequenced from a bacillus thuringiensis subsp. morrisoni bf190 isolated from phylloplane. the upstream promoter region of cry1k was almost identical with that of cry1b. the deduced amino acid sequence of cry1k contains 1215 amino acid residues with an estimated molecular mass of 137 kda. comparison of the amino acid sequence of the cry1k with that of cry proteins revealed that cry1k is most closely related to cry1b and cry1i. cry1k has a hig ... | 1995 | 8586263 |
| cross-resistance of the diamondback moth indicates altered interactions with domain ii of bacillus thuringiensis toxins. | we compared responses to six insecticidal crystal proteins from bacillus thuringiensis by a cry1a-resistant strain (no-qa) and a susceptible strain (lab-p) of the diamondback moth, plutella xylostella. the resistant strain showed > 100-fold cross-resistance to cry1j and to h04, a hybrid with domains i and ii of cry1ab and domain iii or cry1c. cross-resistance was sixfold to cry1bb and threefold to cry1d. the potency of cry1i did not differ significantly between the resistant and susceptible stra ... | 1996 | 8702276 |
| bacillus thuringiensis crystal proteins cry1ab and cry1fa share a high affinity binding site in plutella xylostella (l.). | the future success of bacillus thuringiensis based insecticides depends in part on our ability to prevent insects from developing resistance against their insecticidal crystal proteins. two recent papers indicated cross-resistance between cry1a proteins and cry1fa in two different insect species (tabashnik et al., 1994, appl. environ. microbiol. 60, 4627-4629; gould et al., 1995, j. econ. entomol. 88, 1545-1559). brush border membrane vesicles were prepared from plutella xylostella and used in b ... | 1996 | 8713122 |
| identification of insect cell lines by dna amplification fingerprinting (daf). | fingerprint profiles were generated from twenty insect cell lines spanning the orders, lepidoptera, diptera, coleoptera and homoptera employing dna amplification fingerprinting (daf) with arbitrarily selected primers. the fingerprint pattern is a stable characteristic of the cell line because high and low passages generated the same profile. in addition, insect hosts and homologous cell lines generated similar profiles. all cell lines could be distinguished from each other with the following exc ... | 1996 | 8799737 |
| interactions between the fungal entomopathogen zoophthora radicans brefeld (entomophthorales) and two hymenopteran parasitoids attacking the diamondback moth, plutella xylostella l. | treatment of the hymenopteran parasitoids diadegma semiclausum and cotesia plutellae with a strain of the entomopathogenic fungus zoophthora radicans, which was initially isolated from plutella xylostella, showed that d. semiclausum was susceptible to the pathogen but that c. plutellae was not. in leaf shower bioassays, the susceptibility of d. semiclausum adults to z. radicans was 70- and 133-fold less than the susceptibility of p. xylostella larvae and adults, respectively. when adult d. semic ... | 1996 | 8812558 |
| insecticidal activity of the protein encoded by the cryv gene of bacillus thuringiensis kurstaki ina-02. | a new host specificity was discovered with the insecticidal protein encoded by the cryv gene. the cryv gene was cloned from the bacillus thuringiensis kurstaki ina-02 strain, which was selected among a number of b. thuringiensis isolates because of its high activity against spodoptera litura. analyses by polymerase chain reaction (pcr) revealed that ina-02 contained the cryia(a) and cryv genes. since no spodoptera activity was observed with b. thuringiensis sotto, which contained only cryia(a), ... | 1996 | 8867460 |
| expression of 135-kda insecticidal protein gene from bacillus thuringiensis in the yeast saccharomyces cerevisiae. | bacillus thuringiensis subsp. aizawai produces 130-kda and 135-kda (cryia(a)) insecticidal proteins. when saccharomyces cerevisiae was transformed by the vector carrying a cryia(a) gene, the gene expression could not be observed. when the 5'-upstream region from the initiation codon was removed using a synthetic oligonucleotide, the cryia(a) protein was successfully synthesized in yeast. the yeast extract containing cryia(a) protein had insecticidal activity against plutella xylostella larvae. | 1996 | 8987598 |
| one gene in diamondback moth confers resistance to four bacillus thuringiensis toxins. | environmentally benign insecticides derived from the soil bacterium bacillus thuringiensis (bt) are the most widely used biopesticides, but their success will be short-lived if pests quickly adapt to them. the risk of evolution of resistance by pests has increased, because transgenic crops producing insecticidal proteins from bt are being grown commercially. efforts to delay resistance with two or more bt toxins assume that independent mutations are required to counter each toxin. moreover, it g ... | 1997 | 9050831 |
| aminopeptidase dependent pore formation of bacillus thuringiensis cry1ac toxin on trichoplusia ni membranes. | the insecticidal bacillus thuringiensis cry1ac delta-endotoxin specifically binds to a 120 kda aminopeptidase n (apn) in the midgut of susceptible insects such as manduca sexta, heliothis virescens, lymantria dispar and plutella xylostella. the 120 kda apn has a glycosylphosphatidylinositol (gpi) anchor susceptible to the action of gpi-specific phospholipase c (piplc). here we show that cry1ac pore-forming activity depends on the amount of apn present on brush border membrane vesicles (bbmv) fro ... | 1997 | 9315707 |
| cloning and characterization of manduca sexta and plutella xylostella midgut aminopeptidase n enzymes related to bacillus thuringiensis toxin-binding proteins. | we report the purification, cloning and characterization of an aminopeptidase n from the midgut epithelium of manduca sexta that binds cry1ab5, an insecticidal crystal protein [icp] from bacillus thuringiensis. sequence information derived from this m. sexta aminopeptidase n was used for the cloning of an aminopeptidase n from the midgut brush-border membrane of plutella xylostella, an insect species of which some populations acquired resistance against cry1ab5. affinity chromatography on a cry1 ... | 1997 | 9342226 |
| global variation in the genetic and biochemical basis of diamondback moth resistance to bacillus thuringiensis. | insecticidal proteins from the soil bacterium bacillus thuringiensis (bt) are becoming a cornerstone of ecologically sound pest management. however, if pests quickly adapt, the benefits of environmentally benign bt toxins in sprays and genetically engineered crops will be short-lived. the diamondback moth (plutella xylostella) is the first insect to evolve resistance to bt in open-field populations. here we report that populations from hawaii and pennsylvania share a genetic locus at which a rec ... | 1997 | 9371752 |
| cloning and expression of full-length delta-endotoxin cryia(c) gene in three kinds of prokaryotic systems using shuttle vector pht3101. | two fragments, 6.5kb and 4.3kb encoding 5' end and 3' end of delta-endotoxin cryia(c) gene, respectively, were selected from the bacillus thuringiensis kurstaki-hd-73 75kb plasmid gene pool using random primer labelling delta-endotoxin cryia(b) gene probe. the full-length 3.92kb cryia(c) gene including 5' end 152 bp promoter sequence and 3' end 198 bp terminater sequence was rebuilt after uncoding sequences were deleted. three kinds of engineering strains harbouring the same recombinant plasmid ... | 1996 | 9639817 |
| [characterization of insecticidal crystal proteins of bacillus thuringiensis subsp. chinensis ct-43]. | bacillus thuringiensis subsp. chinensis ct-43, no flagellum, produces various shaped parasporal crystals, which consist of 140000, 130000, and 65000 proteins. based on two kinds of mutant, 140000 and 130000 crystal protein individually forms bipyramidal crystal and the 65000 protein forms cubidal crystal, and that the 140000 and 130000 protein is activated by trypsin into 55000 and 66000 proteins and 60000 protein, respectively. bioassay were conducted to 3rd instar plutella xylostella larvae wi ... | 1996 | 9639832 |
| distribution, serological identification, and pcr analysis of bacillus thuringiensis isolated from soils of korea. | a total, 58 strains of bacillus thuringiensis were isolated from soils of various regions in korea. serological tests showed that b. thuringiensis isolates represented 10 h serotypes, indicating a varied flora of b. thuringiensis. but the h serotypes did not have a significantly uneven distribution, ranging from 1 to 11 isolates. in toxicity tests, 35% of all isolates were toxic to lepidoptera, 20% were toxic to diptera, and 9% were non-toxic isolates. especially, a large number of lepidopteran/ ... | 1998 | 9688820 |
| environmental distribution and diversity of bacillus thuringiensis in spain. | bacillus thuringiensis was isolated from 301 out of 1,005 samples collected in spain from agricultural and non-cultivated soils, dust from stored products, and dead insects. based on the production of parasporal crystals, 1,401 isolates were identified as b. thuringiensis after examining 11,982 b. thuringiensis-like colonies. we found a greater presence of b. thuringiensis in dust from grain storages than in other habitats. sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the spore-c ... | 1998 | 9741114 |
| molecular cloning and heterologous expression of a glutathione s-transferase involved in insecticide resistance from the diamondback moth, plutella xylostella. | four glutathione s-transferase (gst, ec 2.5.1.18) isozymes have been characterized in the larvae of the diamondback moth (dbm), plutella xylostella l., a cosmopolitan insect pest of crucifiers. this work aimed at cloning and heterologously expressing the cdna of dbm gst-3, an isozyme involved in this insect resistance to some organophosphorus insecticides, and studying the molecular basis for its increased expression in the resistant strains. reverse-transcription polymerase chain reaction (rt-p ... | 1998 | 9755475 |
| suppression of diamondback moth (lepidoptera: plutellidae) with an entomopathogenic nematode (rhabditida: steinernematidae) and bacillus thuringiensis berliner. | we tested the efficacy of the all strain of steinernema carpocapsae (weiser) against larvae of the diamondback moth, plutella xylostella (l.). in laboratory bioassays we found that (1) commercially formulated nematodes produced in vitro were as effective as nematodes produced in vivo, (2) resistance of p. xylostella to bacillus thuringiensis berliner subsp. kurstaki did not confer cross-resistance to nematodes, (3) mortality caused by nematodes was higher for early than late 3rd-instar p. xylost ... | 1998 | 9805498 |
| cloning and sequence analysis of the aminopeptidase n isozyme (apn2) from bombyx mori midgut. | an aminopeptidase n (apn) isozyme having the molecular weight of 90 kda, was released by phosphatidylinositol-specific phospholipase c (pi-plc) and purified homogeneously, from the brush border membrane of bombyx mori. from the result of cdna cloning, the primary structure of 90 kda apn proved to consist of 948 amino acid residues, containing a typical metalloprotease-specific zinc-binding motif in the deduced sequence. moreover, the primary sequence contained two hydrophobic segments on n- and ... | 1998 | 9972296 |
| integrative model for binding of bacillus thuringiensis toxins in susceptible and resistant larvae of the diamondback moth (plutella xylostella). | insecticidal crystal proteins from bacillus thuringiensis in sprays and transgenic crops are extremely useful for environmentally sound pest management, but their long-term efficacy is threatened by evolution of resistance by target pests. the diamondback moth (plutella xylostella) is the first insect to evolve resistance to b. thuringiensis in open-field populations. the only known mechanism of resistance to b. thuringiensis in the diamondback moth is reduced binding of toxin to midgut binding ... | 1999 | 10103230 |
| expression of delta-endotoxin cryia(c) gene of bacillus thuringiensis in escherichia coli and streptomyces lividans. | the cryia(c) gene of bacillus thuringiensis was isolated from plasmid pos1000. in order to obtain a proper cloning site and open reading frame, some dna sequences preceding the initiating codon of the gene were replaced by synthetic oligonucleotide sequences. the isolated cryia(c) was cloned into e. coli expression vector pkk223-3, and production of cryia(c) protein was detected after induction by iptg. a recombinant plasmid, phz1256, was constructed by insertion of the cryia(c) gene into strept ... | 1998 | 10196629 |
| microsporidian intrasporal sugars and their role in germination. | the hypothesis that spores of terrestrial and aquatic microsporidia differ in their utilization of sugars was tested by evaluating the sugars in germinated and ungerminated spores of several species in each category. the aquatic species tested were vavraia culicis, edhazardia aedis, and nosema algerae and the terrestrial species were vairimorpha necatrix, nosema disstriae, nosema apis, vairimorpha lymantriae, and nosema spp. from spodoptera exigua and plutella xylostella. the percentage germinat ... | 1999 | 10222184 |
| role of bacillus thuringiensis toxin domains in toxicity and receptor binding in the diamondback moth | the toxic fragment of bacillus thuringiensis crystal proteins consists of three distinct structural domains. there is evidence that domain i is involved in pore formation and that domain ii is involved in receptor binding and specificity. it has been found that, in some cases, domain iii is also important in determining specificity. furthermore, involvement of domain iii in binding has also been reported recently. to investigate the role of toxin domains in the diamondback moth (plutella xyloste ... | 1999 | 10223976 |
| replication of spodoptera exigua nucleopolyhedrovirus in permissive and non-permissive lepidopteran cell lines. | the spodoptera exigua multinucleocapsid nucleopolyhedrovirus (semnpv) was inoculated to eight lepidopteran cell lines derived from spodoptera exigua (se301), spodoptera frugiperda (sf21aeii), spodoptera littoralis (cls-79), spodoptera litura (spli-221), pseudaletia separata (lese-11), trichoplusia ni (hi-5), plutella xylostella (pxl/c) and bombyx mori (bmn4). the productive infection of semnpv was observed only in se301 cells. however, a dot-blot hybridization analysis revealed that semnpv dna r ... | 1998 | 10358729 |
| bacillus thuringiensis insecticidal cry1aa toxin binds to a highly conserved region of aminopeptidase n in the host insect leading to its evolutionary success. | bacillus thuringiensis insecticidal protein, cry1aa toxin, binds to a specific receptor in insect midguts and has insecticidal activity. therefore, the structure of the receptor molecule is probably a key factor in determining the binding affinity of the toxin and insect susceptibility. the cdna fragment (px frg1) encoding the cry1aa toxin-binding region of an aminopeptidase n (apn) or an apn family protein from diamondback moth, plutella xylostella midgut was cloned and sequenced. a comparison ... | 1999 | 10366728 |
| a new aminopeptidase from diamondback moth provides evidence for a gene duplication event in lepidoptera. | we screened a midgut cdna library from diamondback moth, plutella xylostella, with a probe generated using sequence information from an aminopeptidase n gene from manduca sexta (msapn-1). the sequence recovered (pxapn-a) encodes a protein of 988 resides with a 60% sequence identity to msapn-1. the two proteins share a signal peptide which directs processing by the endoplasmic reticulum, a c-terminal hydrophobic region satisfying the criterion for a gpi anchor and cleavage, and the possibility of ... | 1999 | 10380100 |
| genetic mapping of resistance to bacillus thuringiensis toxins in diamondback moth using biphasic linkage analysis. | transgenic plants producing environmentally benign bacillus thuringiensis (bt) toxins are deployed increasingly for insect control, but their efficacy will be short-lived if pests adapt quickly. the diamondback moth (plutella xylostella), a worldwide pest of vegetables, is the first insect to evolve resistance to bt toxins in open-field populations. a recessive autosomal gene confers resistance to at least four bt toxins and enables survival without adverse effects on transgenic plants. allelic ... | 1999 | 10411882 |
| differential activity and activation of bacillus thuringiensis insecticidal proteins in diamondback moth, plutella xylostella. | whole-crystal preparations from strains hd-1 and hd-133, activated cry1ab and cry1c toxins as well as cry1aa, cry1ac, cry1d, and cry2aa protoxins were tested for toxicity to 2nd-instar larvae of the diamondback moth, plutella xylostella. mortality data recorded after 2 and 5 days provided different results that were related to differential rates of solubilization, activation, and degradation of insecticidal crystal proteins. the two most active proteins are cry1ab and cry1c, which are both prese ... | 1999 | 10441730 |
| impact of vairimorpha sp. (microsporidia: burnellidae) on trichogramma chilonis (hymenoptera, trichogrammatidae), a hymenopteran parasitoid of the cabbage moth, plutella xylostella (lepidoptera, yponomeutidae). | a multi-generation mass breeding colony of the cabbage moth, plutella xylostella, was found to be infected with a microsporidium, vairimorpha sp., which is passed transovarially between generations. the microsporidian infection had little impact on the fitness of this lepidopteran pest. however, when trichogramma chilonis parasitized such infected host eggs, the offspring of this parasitoid species suffered from severe deficiencies. microsporidian spores, ingested by parasitoid larvae together w ... | 1999 | 10486223 |
| vairimorpha imperfecta n.sp., a microsporidian exhibiting an abortive octosporous sporogony in plutella xylostella l. (lepidoptera: yponomeutidae). | the microsporidian genus nosema is characterized by development in direct control with host cell cytoplasm, diplokaryotic nuclei throughout development and disporous sporogony. the genus vairimorpha exhibits the same features plus an octoporous sporogony producing uninucleate spores in a sporophorous vesicle. a microsporidium from diamondback moth, plutella xylostella, falls between nosema and vairimorpha in that it initiates but fails to complete the octosporous sequence in this host. the name ... | 1999 | 10503253 |
| helix 4 of the bacillus thuringiensis cry1aa toxin lines the lumen of the ion channel. | the mode of action of bacillus thuringiensis insecticidal proteins is not well understood. based on analogies with other bacterial toxins and ion channels, we hypothesized that charged amino acids in helix 4 of the cry1aa toxin are critical for toxicity and ion channel function. using plutella xylostella as a model target, we analyzed responses to cry1aa and eight proteins with altered helix 4 residues. toxicity was abolished in five charged residue mutants (e129k, r131q, r131d, d136n, d136c), h ... | 1999 | 10542230 |
| infectivity studies of a new baculovirus isolate for the control of the diamondback moth (plutellidae: lepidoptera). | this study describes a new baculovirus isolate recovered from infected larvae of the diamondback moth, plutella xylostella (l.), and identified as a multiple nucleopolyhedrovirus (mnpv). the plaque purified isolate designated as pxmnpvcl3 was found to be pathogenic to p. xylostella, heliothis virescens (f.), trichoplusia ni (hübner), h. subflexa (guenée), helicoverpa zea (boddie), spodoptera exigua (hübner), and s. frugiperda (j. e. smith) larvae in decreasing order of susceptibility. the lc50 f ... | 1999 | 10582047 |
| cloning of two new cry genes from bacillus thuringiensis subsp. wuhanensis strain. | with pcr products as probes, we have cloned two new cry-type genes from bacillus thuringiensis subsp. wuhanensis. the deduced amino acid sequence of the first clone is 77.3% identical to cry1ga1. the deduced protein sequence of the second clone is 69.8-78.7% identical to that of cry1b group. the nomenclature assignment of these two clones is, therefore, named cry1gb1 and cry1bd1, respectively. the cry1bd1 is toxic to plutella xylostella larvae, and the cry1gb1 is toxic to pieris rapae larvae. | 2000 | 10688690 |
| cdnas of aminopeptidase-like protein genes from plodia interpunctella strains with different susceptibilities to bacillus thuringiensis toxins. | aminopeptidase n has been reported to be a bacillus thuringiensis (bt) cry1a toxin-binding protein in several lepidopteran insects. cdnas of aminopeptidase-like proteins from both bt-susceptible rc688s and bt-resistant hd198r strains of the indianmeal moth, plodia interpunctella, were cloned and sequenced. they contain 3345 and 3358 nucleotides, respectively, and each has a 3048 bp open reading frame that encodes 1016 amino acids. putative protein sequences include 10 potential glycosylation sit ... | 2000 | 10732989 |
| genetic and biochemical approach for characterization of resistance to bacillus thuringiensis toxin cry1ac in a field population of the diamondback moth, plutella xylostella. | four subpopulations of a plutella xylostella (l.) strain from malaysia (f(4) to f(8)) were selected with bacillus thuringiensis subsp. kurstaki hd-1, bacillus thuringiensis subsp. aizawai, cry1ab, and cry1ac, respectively, while a fifth subpopulation was left as unselected (unsel-mel). bioassays at f(9) found that selection with cry1ac, cry1ab, b. thuringiensis subsp. kurstaki, and b. thuringiensis subsp. aizawai gave resistance ratios of >95, 10, 7, and 3, respectively, compared with unsel-mel ... | 2000 | 10742234 |
| phagocytosis of vairimorpha sp. (microsporida, nosematidae) spores by plutella xylostella and panorpa vulgaris hemocytes. | | 2000 | 10753600 |
| larval susceptibility of the diamondback moth, plutella xylostella (lepidoptera: plutellidae), to bacillus thuringiensis h serovars isolated in japan. | a total of 1700 japanese strains of bacillus thuringiensis, belonging to at least 47 h serogroups, were examined for insecticidal activity against larvae of the diamondback moth, plutella xylostella. the high-level toxicity was associated with 612 isolates (36.0%). of these, 608 isolates (99.3%) fell into 13 h serogroups belonging to the low-numbered h serotypes, h1-h10. conversely, most isolates belonging to the high-numbered serotypes (>h10) had little or no larvicidal activity; only one isola ... | 2000 | 10830896 |
| effect of insecticides on the diamondback moth (lepidoptera: plutellidae) and its parasitoid diadegma insulare (hymenoptera: ichneumonidae). | studies were conducted to evaluate the toxicity of insecticides to adult diadegma insulare (cresson) and its host the diamondback moth, plutella xylostella (l.). leaf-dip and direct-dip bioassays for diamondback moth larvae and residual bioassays for adults of diamondback moth and d. insulare were used to assess mortalities. larval mortalities at field rates were significantly higher with carbaryl, permethrin, spinosad, and tebufenozide when compared with bacillus thuringiensis, or imidacloprid ... | 2000 | 10902328 |
| assessment of insecticide resistance after the outbreak of diamondback moth (lepidoptera: plutellidae) in california in 1997. | during an outbreak of the diamondback moth, plutella xylostella (l.), in california in 1997, nine populations were collected from the major broccoli areas throughout the state. populations were assayed for their susceptibility to currently used materials (bacillus thuringiensis subsp. kurstaki, permethrin, and methomyl) and to newer materials that had not yet been commercially used in california (spinosad, emamectin benzoate, and chlorfenapyr). for the currently used insecticides, elevated level ... | 2000 | 10902352 |
| susceptibility of plutella xylostella (l.) (lepidoptera: plutellidae) populations in mexico to commercial formulations of bacillus thuringiensis. | populations of diamondback moth, plutella xylostella (l.), sampled from commercial fields of crucifers in three states of mexico, were tested for susceptibility to commercial formulations of bacillus thuringiensis subsp. kurstaki (berliner) (dipel 2x), b. thuringiensis subsp. aizawai (xentari), delta endotoxin cry 1c (mc), and cryia(c) (mvp), and a mixture of b. thuringiensis subsp. kurstaki and subsp. aizawai (agree). leaf-dip bioassays confirmed variation in susceptibility of up to 13-fold for ... | 2000 | 10902356 |
| cloning of a new bacillus thuringiensis cry1i-type crystal protein gene. | a new cry1i-type gene, cry1id1, was cloned from a b. thuringiensis isolate, and its nucleotide sequence was determined. the deduced amino acid sequence of cry1id1 is 89.7%, 87.2%, and 83.4% identical to the cry1ia, cry1ib, and cry1ic proteins, respectively. the upstream sequence of the cry1id1 structural gene was not functional as promoter in b. subtilis. the cry1id1 protein, purified from recombinant e. coli cells, had a toxicity comparable to that of cry1ia against plutella xylostella, but it ... | 2000 | 10919402 |
| development and characterization of diamondback moth resistance to transgenic broccoli expressing high levels of cry1c. | a field-collected colony of the diamondback moth, plutella xylostella, had 31-fold resistance to cry1c protoxin of bacillus thuringiensis. after 24 generations of selection with cry1c protoxin and transgenic broccoli expressing a cry1c protein, the resistance that developed was high enough that neonates of the resistant strain could complete their entire life cycle on transgenic broccoli expressing high levels of cry1c. after 26 generations of selection, the resistance ratios of this strain to c ... | 2000 | 10966391 |
| long pcr improves wolbachia dna amplification: wsp sequences found in 76% of sixty-three arthropod species. | bacteria belonging to the genus wolbachia are associated with a variety of reproductive anomalies in arthropods. allele-specific polymerase chain reaction (= standard pcr) routinely has been used to amplify wolbachia dna from arthropods. while testing the two-spotted spider mite tetranychus urticae and other arthropods known to be infected with wolbachia, standard pcr frequently produced false negatives, perhaps because the dna from the arthropod host interfered with amplification by taq dna pol ... | 2000 | 10971717 |
| seasonal abundance of the parasitoid complex associated with the diamondback moth, plutella xylostella (lepidoptera: plutellidae) in hangzhou, china. | an investigation of insect parasitoids of the diamondback moth, plutella xylostella (linnaeus), in brassica vegetable crops in the suburbs of hangzhou was conducted during five periods from 1989 to 1997. eight species of primary parasitoids were recorded: trichogramma chilonis ishii, cotesia plutellae kurdjumov, microplitis sp., oomyzus sokolowskii kurdjumov, diadromus collaris (gravenhorst), itoplectis naranyae (ashmead), exochus sp. and brachymeria excarinata gahan. seven species of hyperparas ... | 2000 | 10996863 |
| conflicts between a fungal entomopathogen, zoophthora radicans, and two larval parasitoids of the diamondback moth. | zoophthora radicans (zygomycetes: entomophthorales), diadegma semiclausum (hymenoptera: ichneumonidae), and cotesia plutellae (hymenoptera: braconidae) are all natural enemies of the diamondback moth, plutella xylostella (lepidoptera: yponomeutidae). adult c. plutellae are not susceptible to z. radicans infection but the pathogen can infect and kill adult d. semiclausum. infection of adult d. semiclausum prior to exposure to p. xylostella host larvae significantly reduced the number of parasitoi ... | 2000 | 11023731 |
| identification of the diadegma species (hymenoptera: ichneumonidae, campopleginae) attacking the diamondback moth, plutella xylostella (lepidoptera: plutellidae). | the species of diadegma that attack plutella xylostella (linnaeus) are revised. following a morphometric study involving principal components and discriminant analyses, seven distinct morphospecies are recognized. one species is described as new: d. novaezealandiae from new zealand. diadegma mollipla (holmgren) is the name for the species from sub-saharan africa and some indian ocean and south atlantic islands. diadegma varuna gupta syn. nov. and d. niponica kusigemati syn. nov. are both synonym ... | 2000 | 11082555 |
| toxicity of chitinase-producing bacillus thuringiensis ssp. kurstaki hd-1 (g) toward plutella xylostella. | one-hundred fifty isolates of bacillus thuringiensis were tested for their ability to produce chitinase using colloidal chitin agar as the primary plating medium. of 14 strains that produced chitinase, b. thuringiensis ssp. kurstaki hd-1(g) was identified as the highest chitinase producer and selected for further study. this bacterium produced the highest amount of chitinase (19.3 mu/ml) when it was cultivated in nutrient broth supplemented with 0.3% colloidal chitin on a rotary shaker (200 rpm) ... | 2000 | 11112372 |
| [the characteristics of bacillus thuringiensis strain ybt833 and its transformants that containing different icp genes]. | four different transformants were selected by transferring cry1c into bacillus thuringiensis strain ybt833. southern blot and plasmid profiles results all proved that cry1c was transferred into strain ybt833. however, it was found by pcr analysis that transformant ybt833-1 kept all indigenous icp(insecticidal crystal protein) genes of strain ybt833 while transformant ybt833-2 lost cry1ab, and transformant ybt833-3 lost all icp genes. sds-page showed that transformants of ybt833-1, ybt833-2 and y ... | 2000 | 11132501 |
| cyt1a from bacillus thuringiensis lacks toxicity to susceptible and resistant larvae of diamondback moth (plutella xylostella) and pink bollworm (pectinophora gossypiella). | we tested cyt1aa, a cytolytic endotoxin of bacillus thuringiensis, against susceptible and cry1a-resistant larvae of two lepidopteran pests, diamondback moth (plutella xylostella) and pink bollworm (pectinophora gossypiella). unlike previous results obtained with mosquito and beetle larvae, cyt1aa alone or in combination with cry toxins was not highly toxic to the lepidopteran larvae that we examined. | 2001 | 11133481 |
| assessment of insecticide resistance in five insect pests attacking field and vegetable crops in nicaragua. | field populations of hypothenemus hampei (ferrari), plutella xylostella (l.), spodoptera exigua (hübner), helicoverpa zea (boddie) and bemisia tabaci (gennadius) were tested for resistance to several insecticides commonly used in nicariagua. assays were conducted to estimate the ld50s or lc50s and the corresponding resistance ratios. a diagnostic concentration was used to discriminate between susceptible and resistant strains of h. hampei. the tests with >6,000 h. hampei adults collected from si ... | 2000 | 11142313 |
| mannose phosphate isomerase isoenzymes in plutella xylostella support common genetic bases of resistance to bacillus thuringiensis toxins in llpidopteran species. | a strong correlation between two mannose phosphate isomerase (mpi) isoenzymes and resistance to cry1a toxins from bacillus thuringiensis has been found in a plutella xylostella population. mpi linkage to cry1a resistance had previously been reported for a heliothis virescens population. the fact that the two populations share similar biochemical, genetic, and cross-resistance profiles of resistance suggests the occurrence of homologous resistance loci in both species. | 2001 | 11157273 |
| transgenic crop plants expressing synthetic cry9aa gene are protected against insect damage. | a synthetic gene sequence of cry9aa was made to achieve high expression levels in a plant cell. tobacco, potato, cauliflower and turnip rape plants were transformed with this synthetic gene driven by the double 35s promoter using agrobacterium tumefaciens lba4404. the presence and expression of the synthetic cry9aa gene was evaluated in southern, northern and western analysis and with insect bioassays. the expression of the gene in tobacco plants reached a level of 5 pg of mrna per 1 µg of total ... | 2001 | 11164606 |
| [transfer of cry1c gene into bacillus thuringiensis by electroporation to construct strain with broader insecticidal activity]. | three transformants were selected by transferring cry1c into bacillus thuringiensis strain ybt1535. plasmid profiles, pcr and southern blot result all proved that cry1c had been transferred into strain ybt1535. bioassay results showed that the transformants of strain ybt1535 displayed significantly higher toxicity against spodoptera exigua than strain ybt1535, but the toxicities against heliothis armigera and plutella xylostella did not rise except transformant ybt1535-2. | 2000 | 11191763 |
| [expression of 2.1 kb enhancin gene fragment from helicoverpa armigera granulosis virus in escherichia coli]. | the 2.1 kb fragment of enhancin gene from helicoverpa armigera granulosis virus was inserted into vector pqe-30 and expressed successfully in e. coli m15(prep4). the synergy of expression product(p78) on acmnpv against the larvae of plutella xylostella was also studied. the results indicated that the percentage of correct mortality of the larvae increased 27.88%-32.92% in 10 post-infection days. | 2000 | 11191765 |
| greenhouse tests on resistance management of bt transgenic plants using refuge strategies. | experimental evaluation of the effectiveness of resistance management tactics is vital to help provide guidelines for the deployment of transgenic insecticidal crops. transgenic broccoli expressing a cry1ac gene of bacillus thuringiensis (bt) and the diamondback moth, plutella xylostella (l.), were used in greenhouse tests to evaluate the influence of size and placement of nontransgenic refuge plants on changes in resistance allele frequency and pest population growth. in the first test with an ... | 2001 | 11233120 |
| screening of the bacillus thuringiensis cry1ac delta-endotoxin on the artificial phospholipid monolayer incorporated with brush border membrane vesicles of plutella xylostella by optical biosensor technology. | the binding of cry1ac, an insecticidal protein of bacillus thuringiensis, to a brush border membrane (bbm) isolated from midguts of the diamondback moth plutella xylostella was examined by surface plasmon resonance (spr)-based biosensor. bbm was mixed with 1,3-ditetradecylglycero-2-phosphocholine (pc14), a neutral charged artificial lipid, and was reconstructed to a monolayer on a hydrophobic chip for the biosensor. the binding of cry1ac to the reconstructed monolayer was analyzed by a two-state ... | 2001 | 11245889 |
| effects of a mustard trypsin inhibitor expressed in different plants on three lepidopteran pests. | the effects of mustard trypsin inhibitor mti-2 expressed at different levels in transgenic tobacco, arabidopsis and oilseed rape lines have been evaluated against three different lepidopteran insect pests. 1. plutella xylostella (l.) larvae were the most sensitive to the ingestion of mti-2. the inhibitor expressed at high levels in arabidopsis plants caused rapid and complete mortality. high mortality and significantly delayed larval development were also detectable in oilseed rape expressing mt ... | 2001 | 11267898 |
| lipids of brush border membrane vesicles (bbmv) from plutella xylostella resistant and susceptible to cry1ac delta-endotoxin of bacillus thuringiensis. | plutella xylostella (px) that were 130000-fold more resistant to cry1ac were selected from the susceptible strain and maintained in the laboratory. the lc50 of the susceptible strain (pxs) was 0.38 microg toxin/g diet, whereas that of the resistant strain (pxr) was 4800 microg toxin/g diet. brush border membrane vesicles (bbmv) were prepared from both pxs and pxr. in ligand blot analysis, cry1ac bound to a 120-kda protein of bbmv; however, the intensity of the band was almost equal in both strai ... | 2001 | 11337261 |
| cross-resistance and inheritance of resistance to bacillus thuringiensis toxin cry1ac in diamondback moth (plutella xylostella l) from lowland malaysia. | a field population of plutella xylostella from malaysia (serd4) was divided into five sub-populations and four were selected (g2-g5) with the bacillus thuringiensis insecticidal crystal (cry) toxins cry1ac, cry1ab, cry1ca and cry1da. bioassay at g6 gave resistance ratios of 88, 5, 2 and 3 for cry1ac, cry1ab, cry1ca and cry1da respectively compared with the unselected sub-population (unsel-serd4). the cry1ac-selected population showed little cross-resistance to cry1ab, cry1ca and cry1da, (3-, 2- ... | 2001 | 11374157 |
| exchange of domain i from bacillus thuringiensis cry1 toxins influences protoxin stability and crystal formation. | influence of domain i exchange on the stability and production of bacillus thuringiensis cry1 protoxins as well as on the shape of inclusion and toxicity to spodoptera exigua and plutella xylostella larvae was investigated. chimeric genes were prepared by exchanging the regions coding for domain i between cry1aa, cry1ab, cry1ac, cry1c, and cry1e. the accc chimera accumulated into bipyramidal inclusion bodies, whereas cee produced round-shaped inclusion bodies, and ecc and aaee protoxins produced ... | 2001 | 11375655 |
| cross-resistance and stability of resistance to bacillus thuringiensis toxin cry1c in diamondback moth. | we tested toxins of bacillus thuringiensis against larvae from susceptible, cry1c-resistant, and cry1a-resistant strains of diamondback moth (plutella xylostella). the cry1c-resistant strain, which was derived from a field population that had evolved resistance to b. thuringiensis subsp. kurstaki and b. thuringiensis subsp. aizawai, was selected repeatedly with cry1c in the laboratory. the cry1c-resistant strain had strong cross-resistance to cry1ab, cry1ac, and cry1f, low to moderate cross-resi ... | 2001 | 11425744 |
| optimum timing of insecticide applications against diamondback moth plutella xylostella in cole crops using threshold catches in sex pheromone traps. | field trials were conducted in cabbage (brassica oleracea var capitata), cauliflower (b oleracea var botrytis) and knol khol (b oleracea gongylodes) crops at two different locations in karnataka state (india) to optimize the timing of insecticide applications to control the diamondback moth, plutella xylostella, using sex pheromone traps. our results indicate that applications of cartap hydrochloride as insecticide during a 12-24 h period after the pheromone traps had caught on average 8, 12 and ... | 2001 | 11455637 |
| establishment and characterization of insect cell lines from 10 lepidopteran species. | cell lines from selected lepidopteran species were established for the overall purpose of use in baculovirus production. a total of 36 new cell lines from 10 lepidopteran species were generated, including cell lines from a pyralid, the european corn borer, ostrinia nubilalis, a plutellid, the diamondback moth, plutella xylostella, as well as eight noctuids: the black cutworm, agrotis ipsilon, the celery looper, anagrapha falcifera, the velvetbean caterpillar, anticarsia gemmatalis, the corn earw ... | 2001 | 11515970 |
| susceptibility of a field-derived, bacillus thuringiensis-resistant strain of diamondback moth to in vitro-activated cry1ac toxin. | resistant and susceptible populations of the diamondback moth (plutella xylostella) were tested with crystalline, solubilized, and partially and fully activated forms of the bacillus thuringiensis cry1ac delta-endotoxin. fully activated toxin greatly reduced the resistance ratio (ratio of the 50% lethal concentration for the resistant population to that for the susceptible population) of the resistant population, suggesting that a defect in toxin activation is a major resistance mechanism. | 2001 | 11526050 |
| the complete sequence of the cydia pomonella granulovirus genome. | the nucleotide sequence of the dna genome of cydia pomonella granulovirus (cpgv) was determined and analysed. the genome is composed of 123500 bp and has a g+c content of 45.2%. it contains 143 orfs of 150 nucleotides or more that show minimal overlap. one-hundred-and-eighteen (82.5%) of these putative genes are homologous to genes previously identified in other baculoviruses. among them, 73 are homologous to genes of autographa californica nucleopolyhedrovirus (acmnpv), whereas 108 and 98 are h ... | 2001 | 11562546 |
| variation in susceptibility to bacillus thuringiensis toxins among unselected strains of plutella xylostella. | so far, the only insect that has evolved resistance in the field to bacillus thuringiensis toxins is the diamondback moth (plutella xylostella). documentation and analysis of resistant strains rely on comparisons with laboratory strains that have not been exposed to b. thuringiensis toxins. previously published reports show considerable variation among laboratories in responses of unselected laboratory strains to b. thuringiensis toxins. because different laboratories have used different unselec ... | 2001 | 11571163 |
| isolation of bacillus thuringiensis from intertidal brackish sediments in mangroves. | intertidal brackish sediments in mangroves were examined for isolation of bacillus thuringiensis strains with novel toxicity spectra. a total of 18 b. thuringiensis isolates were recovered from eight sediment samples (36.4%) out of 22 samples tested. the frequency of b. thuringiensis was 1.3% among the colonies of bacillus cereus/b. thuringiensis group. while five isolates were allocated to the four h serogroups, the majority of the isolates were serologically untypable or untestable. two isolat ... | 2001 | 11572461 |
| a comparison of techniques for detecting invertebrate iridescent virus 6. | the aim of this study was to compare the sensitivity and precision of various methods for the detection and quantification of invertebrate iridescent virus 6 (iiv-6) (iridoviridae) isolated from a the stem-boring moth chilo suppressalis, and to apply these techniques to the detection of covert infections in the wax moth, galleria mellonella. the relationship between the virus concentration and absorbance at 260 nm was linear over the range of 1.6 x 10(9)-5.6 x 10(10) particles/ml. tcid(50) assay ... | 2001 | 11576637 |
| identification of a novel class of insect glutathione s-transferases involved in resistance to ddt in the malaria vector anopheles gambiae. | the sequence and cytological location of five anopheles gambiae glutathione s-transferase (gst) genes are described. three of these genes, aggst1-8, aggst1-9 and aggst1-10, belong to the insect class i family and are located on chromosome 2r, in close proximity to previously described members of this gene family. the remaining two genes, aggst3-1 and aggst3-2, have a low sequence similarity to either of the two previously recognized classes of insect gsts and this prompted a re-evaluation of the ... | 2001 | 11583575 |
| molecular cloning of a new crystal protein gene cry1af1 of bacillus thuringiensis nt0423 from korean sericultural farms. | a new cry1ab-type gene encoding the 130 kda protein of bacillus thuringiensis nt0423 bipyramidal crystals was cloned, sequenced, and expressed in a crystal-negative b. thuringiensis host. hybridization experiments revealed that the crystal protein gene is located on a 44 mda plasmid of b. thuringiensis nt0423. a strong positive signal detected on the 6.6 kb hindiii fragment from b. thuringiensis nt0423 plasmid dna was cloned and sequenced. the cry1ab-type gene, designated cry1af1, consisted of o ... | 2001 | 11685507 |
| shared binding sites in lepidoptera for bacillus thuringiensis cry1ja and cry1a toxins. | bacillus thuringiensis toxins act by binding to specific target sites in the insect midgut epithelial membrane. the best-known mechanism of resistance to b. thuringiensis toxins is reduced binding to target sites. because alteration of a binding site shared by several toxins may cause resistance to all of them, knowledge of which toxins share binding sites is useful for predicting cross-resistance. conversely, cross-resistance among toxins suggests that the toxins share a binding site. at least ... | 2001 | 11722929 |
| cyt1aa from bacillus thuringiensis subsp. israelensis is toxic to the diamondback moth, plutella xylostella, and synergizes the activity of cry1ac towards a resistant strain. | the bacillus thuringiensis subsp. israelensis cytolytic protein cyt1aa was found to be toxic to an insecticide-susceptible laboratory population of plutella xylostella. cry1ac-resistant populations of p. xylostella showed various degrees of resistance to cyt1aa. cyt1aa/cry1ac mixtures showed a marked level of synergism in the cry1ac-resistant populations. | 2001 | 11722947 |
| mutagenic analysis of a conserved region of domain iii in the cry1ac toxin of bacillus thuringiensis. | we used site-directed mutagenesis to probe the function of four alternating arginines located at amino acid positions 525, 527, 529, and 531 in a highly conserved region of domain iii in the cry1ac toxin of bacillus thuringiensis. we created 10 mutants: eight single mutants, with each arginine replaced by either glycine (g) or aspartic acid (d), and two double mutants (r525g/r527g and r529g/r531g). in lawn assays of the 10 mutants with a cultured choristoneura fumiferana insect cell line (cf1), ... | 2002 | 11772627 |
| cloning and characterization of the crystal protein-encoding gene of bacillus thuringiensis subsp. yunnanensis. | molecular cloning and characterization of a novel cry gene, cry32aa, of bacillus thuringiensis subsp. yunnanensis was carried out. the cry32aa protein was predicted to have a molecular mass of 139.2 kda and was found to have an unusual 42-amino-acid-long tail at the c terminus. the cry32aa gene was localized on the 103-mda plasmid of the organism. bioassays showed no toxicity against several moths and mosquitoes. however, it exhibited weak toxicity against larvae of the diamondback moth, plutell ... | 2002 | 11772653 |
| different cross-resistance patterns in the diamondback moth (lepidoptera: plutellidae) resistant to bacillus thuringiensis toxin cry1c. | two strains of the diamondback moth, plutella xylostella (l.), were selected using cry1c protoxin and transgenic broccoli plants expressing a cry1c toxin of bacillus thuringiensis (bt). both strains were resistant to cry1c but had different cross-resistance patterns. we used 12 bt protoxins for cross-resistance tests, including cry1aa, cry1ab, cry1ac, cry1bb, cry1c, cry1d, cry1e, cry1f, cry1j, cry2ab, cry9aa, and cry9c. compared with the unselected sister strain (bcs), the resistance ratio (br) ... | 2001 | 11777062 |
| penetration of cuticle and proliferation in hemolymph by paecilomyces fumosoroseus isolates that differ in virulence against lepidopteran larvae. | frequencies of cuticular penetration and speed of proliferation in hemolymph were demonstrated for two isolates of paecilomyces fumosoroseus that differ in virulence against diamondback moth, plutella xylostella. penetrant hyphae of virulent isolate 4461 were visible in larval cuticle cross-sections of diamondback moth and fall armyworm, spodoptera frugiperda, within 22 h after inoculation. virtually no penetration was observed for isolate 1576 for up to 52 h after inoculation. isolate 4461 also ... | 2001 | 11812110 |
| examination of the f2 screen for rare resistance alleles to bacillus thuringiensis toxins in the diamondback moth (lepidoptera: plutellidae). | a synthetic laboratory population of the diamondback moth, plutella xylostella (l.), was used to test the f2 screen developed for detecting the frequency of rare resistance alleles to cry1ac and cry1c toxins of bacillus thuringiensis (bt). of the 120 single-pair matings set up, 106 produced enough f2 families for screening of cry1ac or cry1c resistance alleles using both transgenic broccoli and an artificial diet overlay assay with a diagnostic dose. when using bt broccoli plants as the f2 scree ... | 2002 | 11942749 |
| fluorometric microplate assay to measure glutathione s-transferase activity in insects and mites using monochlorobimane. | elevated levels of glutathione s-transferases (gsts) play a major role as a mechanism of resistance to insecticides and acaricides in resistant pest insects and mites, respectively. such compounds are either detoxicated directly via phase i metabolism or detoxicated by phase ii metabolism of metabolites as formed by microsomal monooxygenases. here we used monochlorobimane (mcb) as an artificial substrate and glutathione to determine total gst activity in equivalents of single pest insects and sp ... | 2002 | 11950219 |
| developmental toxicity of flupyrazofos, a new organophosphorus insecticide, in rats. | flupyrazofos is a new type of pyrazole organophosporus insecticide, which has a high activity against the diamond-back moth (plutella xylostella). the potential of this agent to induce developmental toxicity was investigated in the sprague-dawley rat. one hundred mated females (sperm in vaginal lavage=day 0) were distributed among three treated groups and a control group. flupyrazofos was administered by gavage to pregnant rats from days 7-17 of gestation at dose levels of 0, 5, 12 and 30 mg/kg/ ... | 2002 | 11955679 |
| aminopeptidase n isoforms from the midgut of bombyx mori and plutella xylostella -- their classification and the factors that determine their binding specificity to bacillus thuringiensis cry1a toxin. | novel aminopeptidase n (apn) isoform cdnas, bmapn3 and pxapn3, from the midguts of bombyx mori and plutella xylostella, respectively, were cloned, and a total of eight apn isoforms cloned from b. mori and p. xylostella were classified into four classes. bacillus thuringiensis cry1aa and cry1ab toxins were found to bind to specific apn isoforms from the midguts of b. mori and p. xylostella, and binding occurred with fragments that corresponded to the bmapn1 cry1aa toxin-binding region of each apn ... | 2002 | 12023048 |
| recombinant scorpion insectotoxin aait kills specifically insect cells but not human cells. | the nucleotide sequence deduced from the amino acid sequence of the scorpion insectotoxin aait was chemically synthesized and was expressed in escherichia coli. the authenticity of this in vitro expressed peptide was confirmed by n-terminal peptide sequencing. two groups of bioassays, artificial diet incorporation assay and contact insecticidal effect assay, were carried out separately to verify the toxicity of this recombinant toxin. at the end of a 24 h experimental period, more than 60% of th ... | 2002 | 12118940 |
| larvicidal activity against plutella xylostella of cordycepin from the fruiting body of cordyceps militaris. | the insecticidal activities of methanol extracts of cordyceps militaris link (ascomycotina: clavicipitaceae) cultured on fresh pupae of bombyx mori l against 3rd-instar larvae of plutella xylostella l were examined using direct contact application. the larvicidal activity was more pronounced in an extract of c militaris fruiting body than in an extract of the pupae separated from the culture. the biologically active constituent of the cordyceps fruiting body was characterized as cordycepin (3'-d ... | 2002 | 12146173 |