• International Journal of Industrial Entomology and Biomaterials
• /
• v.4 no.1
• /
• pp.43-49
• /
• 2002

We have cloned cDNAs encoding toxin from the spider, Araneus ventricosus, and constructed a recombinant baculovirus expressing the insecticidal toxin. The cDNAs encoding toxin were cloned from the cDNA library of A. ventricosus. Sequence analysis of the cDNAs encoding the toxin of A. ventricosus revealed that the 240 bp cDNA for AvTox-1 and 192 bp cDNA for AvTox-2 have an open reading frame of 80 and 64 amino acid residues, respectively. The deduced protein sequence of the toxin genes of AvTox-1 and AvTox-2 was aligned to that of the snack Anemonia sulcata and scorpion Centruroides limpidus limpidus, respectively. Northern blot analysis indicated that AvTox-2 toxin gene showed a fat body-spe-cific expression pattern at the transcriptional level. Furthermore, we have explored the possibility of improving baculovirus by incorporating the A. vontricosus toxin gene into Bombyx mori nuclear polyhedrosis virus genome under the control of polyhedrin promoter, The AvTox-2 toxin gene was expressed as approximately 5.8 kDa band in the recombinant baculovirus-injected silkworm larvae. Bioassays with the recombinant virus expressing AvTox-2 on 5th instar silkworm larvae demonstrated a decrease in the time to kill $(LT_{50} days)$ compared to wild-type BmNPV-Kl $(LT_{50} 6.72 days)$ in the injection of 10 viruses. These results indicate that A. ventricosus toxin is a novel member of the spider toxin family, suggesting that the toxin gene can be used in recombinant baculoviruses to reduce insect feeding damage and increase the speed of insect kill.

• Applied Biological Chemistry
• /
• v.35 no.4
• /
• pp.227-231
• /
• 1992

The plasmids pSUPBT and pSUPBTR were constructed with a vector pSUP2021 and the BT toxin gene in the plasmid pES 1. The plasmids constructed were introduced into the antagonistic rhizobacteria P. fluorescens KR164 by conjugation and P. fluorescens having pSUPBT and pSUPBTR were named P. fluorescens KR164(pSUPBT)#2, KR164(pSUPBT)#3, KR164(pSUPBTR)#2 and KR164(pSUPBTR)#3, respectively. The BT toxin gene were identified in all transformants by Southern hybridization and the final product of BT toxin gene was identified only in P. fluorescens KR164(pSUPBTR)#3 by SDS-PAGE. This crystal toxin protein were also observed in electron microscopy.

• Korean Journal of Microbiology
• /
• v.30 no.3
• /
• pp.160-163
• /
• 1992

Killer toxin from killer yeast fusant FWKS 260 developed by protoplast fusion between the wild killer yeast and alcohol-fermenting yeast was purified by ammonium sulfate fractionation. Amicon PM I0 concentration. Sephadex G-200 and Scphadcx G-75 column chromatography. The purified killer toxin showed a single band by SIX-polyacvlamide gel electrophoresis. The protein part of killer toxin was active site. which was found by treating the proteolytic enzyme such as pronase E and pepsin to killer toxin. The killer toxin was stable at pH 2.0-5.0 and 20$^{\circ}$C. but inactivated with increasing temperature. The molecular weight was determined to be approximately 13.000 according to the results obtained from the SDS-polyacrylamide gel electrophoresis. It was confirmed that the purified killer toxin is glycoprotein by showing a red single band after st'tining with Schiffs reagent.

• Animal cells and systems
• /
• v.1 no.3
• /
• pp.507-513
• /
• 1997

Sequential observations of binding patterns and structural effects of Bacillus thuringiensis var. kurstaki were made on fat body tissue of the fall webworm, Hyphantria cunea Drury. Fat body was cultured in vitro in the presence of purified 62 kDa endotoxin and then examined for protein synthesis and the localization of membrane-bound toxin detected by an antibody against the 62 kDa endotoxin. Protein synthesis was mostly inhibited at concentrations of 15 ${\mu}$g/ml and higher. Immunocytochemical observations suggest that the toxin binds to all exposed basal lamina surrounding the fat body without apparent specificity. The cytopathic effect delectable by scanning electron microscope is disintegration rather than cell swelling. The basal lamina bound toxin was eventually detached from the fat body and followed by an extrusion of cell contents like lipid granules.

• BMB Reports
• /
• v.36 no.5
• /
• pp.508-513
• /
• 2003

The bacterium Bacillus thuringiensis produces toxin inclusions that are deleterious to target insect larvae. These toxins are believed to interact with a specific receptor protein(s) that is present on the gut epithelial cells of the larvae. In various insect species (in particular those belonging to the lepidopteran class), aminopeptidase N (APN) is one of the two receptor proteins that are considered to be involved in toxin-receptor interactions. However, in mosquitoes, the nature and identity of the receptor protein is unknown. Here, using RT-PCR, we identified two isoforms of the APN transcripts in the Aedes aegypti mosquito larval midgut. These results are congruent with a previous report of multiple isoforms of the APN gene expression in lepidopteran larvae. Which of the two isoforms (or other yet unidentified receptor proteins) is involved in the killing of mosquito larvae remains to be elucidated.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.5 no.2
• /
• pp.141-145
• /
• 2000

Entomopathogenic nematodes are being used for insect control. We purified a toxin secreted by the insect-pathogenic bacterium, Xenorhadbus nematophilus, which lives in the gut of entomopathogenic nematodes. Culture broth of X. nematophilus was separated by centrifugation and concentrated by ultration. The concentrated culture broth was applied to a DEAE Sephadex A-50 column, and proteins were eluted stepwise with increasing concentrations of KCI. Fractions column. The molecty weight of purified toxin was39 kDa on SDS-PAGE, and Fourier tranformed infrared (FTIR) spectroscopy indicated that this toxin could be a new protein exhiting the charactristics of C=O stretching peak near 1650cm-1.

• Development and Reproduction
• /
• v.16 no.1
• /
• pp.69-75
• /
• 2012

Hatching occurred in the time dependent manners and strictly controlled. Although, the hatching processes are under the control of muti-embryotrophic factors and the expressed G proteins of cell generate integrated activation, the knowledge which GPCRs are expressed during hatching stage embryos are very limited. In the present study, which G proteins are involved was examined during blastocyst development to the hatching stage. The early-, expanded-, and lobe-stage blastocysts were treated with various $G_{\alpha}$ activators and H series inhibitors, and examined developmental patterns. Pertusis toxin (PTX) improved the hatching rate of the early-stage blastocyst and lobe-formed embryos. Cholera toxin (CTX) suppressed the hatching of the early-stage blastocyst and expanded embryos. The effects of toxins on hatching and embryo development were changed by the H7 and H8. These results mean that PTX mediated GPCRs activation is signaling generator in the nick or pore formation in the ZP. In addition, PTX mediated GPCR activation induces the locomotion of trophectoderm for the escaping. CTX mediate GPCRs activation is the cause of suppression of hatching processes. Based on these data, it is suggested that various GPCRs are expressed in the periimplantation stage embryos and the integration of the multiple signals decoding of various signals in a spatial and temporal manner regulate the hatching process.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.10
• /
• pp.1630-1633
• /
• 2008

A novel putative toxin-antitoxin segregational stability system named KyAB system was identified in a novel native plasmid pBMB8240 from Bacillus thuringiensis strain YBT-1520, based on sequences homology with other toxin-antitoxin systems, the lethal activity of the KyB putative toxin in Escherichia coli and the stabilizing effect of the kyAB system in Bacillus thuringiensis. Secondarily, the native plasmid pBMB9741 from the same strain was resequenced and the corrected plasmid was named as pBMB7635. Based on sequence homology with the tasAB system and the lethal activity of toxin protein in Escherichia coli, a tasAB-like putative toxin-antitoxin system was identified on pBMB7635.

• Microbiology and Biotechnology Letters
• /
• v.38 no.2
• /
• pp.117-123
• /
• 2010

BT toxin is produced by a soil bacterium Bacillus thuringiensis and has long been used as a biological insecticide without any competition. Recently, Photorhabdus, a symbiotic bacterium from entomopathogenic nematodes, family Heterorhabditae, has been researched and discussed as alternatives to B. thuringiensis. Photorhabdus, which lives in the gut of entomopathogenic nematodes, is a highly virulent pathogen of a wide range of insect larvae. When an insect is infected by the nematodes, the bacteria are released into the cadaver, and produce a number of insecticidal toxins. The biological role of the different Photorhabdus toxins in the infection process is still unclear. Photorhabdus toxin complex (Tc) is highly secreted gut-active toxin and has been characterized as a potent three-component (A, B and C) insecticidal protein complex. These components are necessary for full oral activity against insect larvae. The Photorhabdus PirAB binary toxins exhibit a potent injectable activity for Galleria mellonella larvae, and have oral toxicity against mosquitoes and caterpillar pest Plutella xylostella. Other toxin, 'makes caterpillars floppy' (Mcf) showed injectable activity on caterpillars. Recombinant Mcf triggers apoptosis in both insect hemocytes and the midgut epithelium and carries a BH3 domain. In this review, the relationship between the Photorhabdus and the nematode is discussed and recent important insecticidal toxins from Photorhabdus are described.

• Journal of Animal Science and Technology
• /
• v.62 no.4
• /
• pp.468-474
• /
• 2020

The study was to determine the effects of diverse concentrations of T-2 toxin in broiler diet. Three hundred 1-day-old chicks with initial body weight of 46 ± 0.52 g were chosen and randomly assigned into five dietary treatments with 5 replicate cages and 12 broilers per cage for 42 d feeding trial. Dietary treatments were prepared with basal diets containing 0 (T₁), 50 (T₂), 100 (T₃), 150 (T₄), 200 (T₅) ppb T2-toxin. Significant results were observed in the decreased intake of feed, feed conversion ratio (FCR), body weight gain (BWG), level of serum protein, cholesterol and hemoglobulin of broilers in increased concentration of the T-2 toxin in diet (150 and 200 ppb) groups than control. Also, observed that the uric acid, serum glutamic pyruvic transferase (SGPT), serum glutamic oxaloacetic transferase (SGOT) and Heterophil/Lymphocyte (H/L) ratio value were significantly higher (p < 0.05) in groups T₄ and T₅ than control. However, the BWG, feed intake and FCR, as well blood biochemical profiles of serum protein, cholesterol, hemoglobulin, uric acid, SGPT, SGOT and H/L ratio in groups T₂ and T₃ were statistically similar to control diet of broilers. It was concluded that the results showed that no adverse effects on growth performance and blood biochemical parameters in broilers feed with T-2 toxin (50 and 100 ppb) during the entire trial.