Showing papers on "Bacillus thuringiensis published in 1978"
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TL;DR: Since DNA homology was introduced as a new taxonomic criterion, Somerville and Jones made some DNA-DNA competition experiments and suggested close interrelatendness of the three, though their data do not appear very clearcut.
Abstract: proved as distinct taxa (1, 2), as they are different in pathogenicity and in some other properties. However it is also widely accepted that they are quite similar. In fact some pathogens may produce non-pathogenic offsprings that are hardly distinguishable from normal B. cereus. Some B. cereus strains share some flagella antigens with B. thuringiensis (6; Ohba and Aizawa, unpublished data), and the formation of intracellular protein crystals, which has been considered as another characteristic of the latter, is now known in Bacillus subtilis (4) too. In their comprehensive studies Smith et al (9, 10) and Gordon et al (3) emphasized their similarities rather than difference and took a view that they are from academic viewpoint the different varieties of B. cereus. Since DNA homology was introduced as a new taxonomic criterion, Somerville and Jones (11) made some DNA-DNA competition experiments and suggested close interrelatendness of the three, though their data do not appear very clearcut. DNADNA hybridisation studies by Azuma (personal communication) and by Seki et al
127 citations
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TL;DR: The unique capacity of this species to alter the surface coating of spores which appears to be related to crystal formation may provide flexibility for germination and growth in diverse soil environments.
121 citations
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TL;DR: It was found that most of the crystalliferous isolates belonged to B. thuringiensis serotypes 3a, 4a:4b, 7, and 8, and serotypes 1, 3a:3b, 4 a:4c, and 11 were rarely isolated.
93 citations
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TL;DR: The inactivation of Bacillus thuringiensis spores and spores treated with two protectants, one proteinaceous and the other a commercial product, Shade, at wavelengths of the near-ultraviolet and visible spectra and at 254 nm is described.
Abstract: The inactivation of Bacillus thuringiensis spores and spores treated with two protectants, one proteinaceous and the other a commercial product, Shade, at wavelengths of the near-ultraviolet and visible spectra and at 254 nm is described. Determination of the inactivating wavelengths may be used to establish an efficient sunlight protective system for B. thuringiensis when used as a microbial insecticide.
93 citations
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TL;DR: The rare occurrence of cross-transduction among strains of B. thuringiensis is probably a reflection of nonhomology rather than restriction, since phage itself did not appear to be restricted when grown on a particular host and assayed with other hosts as indicator.
Abstract: Bacteriophage CP-51, originally reported as a generalized transducing phage for Bacillus cereus and B. anthracis, has been shown to carry out generalized transduction in several strains of B. thuringiensis. A newly isolated phage, CP-54, which has a broader host range than CP-51, also mediates generalized transduction in B. thuringiensis. CP-51 and CP-54 are similar in size and morphology and are related serologically, but they are not identical. CP-54 is more cold labile than CP-51, and, as with CP-51, its stability both at 0 and 15 degrees C is enhanced by the presence of 0.02 M Mg2+. Some examples of cotransduction of linked markers in B. thuringiensis are presented, demonstrating the feasibility of chromosomal mapping in this organism. The rare occurrence of cross-transduction among strains of B. thuringiensis is probably a reflection of nonhomology rather than restriction, since phage itself did not appear to be restricted when grown on a particular host and assayed with other hosts as indicator.
79 citations
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TL;DR: The findings supported the assumption that sunlight inactivation of entomopathogens probably is caused by peroxide or peroxide radicals produced by the UV irradiation of amino acid (s).
Abstract: The half-life of unpasteurized and pasteurized dried films of Bacillus thuringiensis exposed to a laboratory UV source was 30 and 45 min, respectively. Films of B. thuringiensis containing peroxidase and exposed to UV were significantly more stable than those not containing peroxidase. The findings supported the assumption that sunlight inactivation of entomopathogens probably is caused by peroxide or peroxide radicals produced by the UV irradiation of amino acid (s).
64 citations
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TL;DR: Two groups distinguishable on the basis of crystal serology have been identified within Bacillus thuringiensis var kurstaki (serotype 3 ab) and the toxicities to Trichoplusia ni and Heliothis virescens expressed as T H ratio differed.
58 citations
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TL;DR: Larvae of the tobacco budworm, Heliothis virescens, which were fed ad libitum on a diet treated with various levels of the δ-endotoxin showed an unexpected capacity to recover from the effects of the toxin, although, as the length of exposure increased, the capacity decreased.
52 citations
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TL;DR: Enzymically activated δ-endotoxin of Bacillus thuringiensis covalently bound to Sephadex beads, has the same effect on insect cells in tissue culture as free toxin, and probably acts at the cell surface.
Abstract: Enzymically activated δ-endotoxin ofBacillus thuringiensis covalently bound to Sephadex beads, has the same effect on insect cells in tissue culture as free toxin. The effect is prevented by antitoxin antibody and heat denaturation and is not due to a nonspecific protein effect, the beads, or toxin released from the beads. The toxin, therefore, probably acts at the cell surface.
42 citations
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TL;DR: B. thuringiensis caused a large increase in the development time of E. cautella larvae but caused little increase in that of P. interpunctella; the bacterium had no discernible effect on the sex ratio or reproductive capacity of moths that developed from surviving larvae.
Abstract: Larvae of the almond moth, Ephestia cautella (Walker), were highly susceptible to Bacillus thuringiensis Berliner in their diet if exposure began during the 1st stadium; they were less susceptible if exposure began dunng the later stadia. Larvae of the Indianmeal moth, Plodia interpunctella (Hubner), also were highly susceptible if exposure began during the 1st or 2nd stadium, but only the last (4th) stadium showed low susceptibility. B. thuringiensis caused a large increase in the development time of E. cautella larvae but caused little increase in that of P. interpunctella . The bacterium had no discernible effect on the sex ratio or reproductive capacity of moths that developed from surviving larvae.
42 citations
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TL;DR: Bacillus thuringiensis produces an active toxin specific to lepidopterous larvae and the activity is associated with a protein crystal produced during sporulation and a related activity is found in the outer layers of spores as mentioned in this paper.
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TL;DR: Several factors that might affect the efficacy of Bacillus thuringiensis against Simulium vittatum larvae were investigated in the laboratory utilizing a conical-flushing rearing unit and the jar method for bioassay.
Abstract: Several factors that might affect the efficacy of Bacillus thuringiensis against Simulium vittatum larvae were investigated in the laboratory utilizing a conical-flushing rearing unit and the jar method for bioassay.
S. vittatum and S. argus were considerably more susceptible to B. thuringiensis than the other species tested. There was a strong positive correlation between temperature and mortality (r = 0.97). The range of mortality for 4°–24°C was 23–95%. The midgut pH ranged from 8.2–11.4, sufficiently high for θ-endotoxin activity.
When spore and crystal fractions were bioassayed separately, only the crystal fraction produced significant mortality. No additive action of the spore and crystal was apparent, activity was solely attributed to the parasporal crystalline inclusion bodies. Spore preparations autoclaved and not autoclaved, containing the β -exotoxin produced a low level of mortality at 10 ppm for 24 h.
Spore suspensions of B. thuringiensis stored at 2° and 19°C remained active for 167 and 28 days, respectively, after which a sharp decline in activity was observed.
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TL;DR: In the laboratory, Heliothis zea (Boddie) larvae that were fed foliage of ED73–371, a genotype resistant to the Mexican bean beetle, Epilachna varivestis Mulsant, weighed less and were more susceptible to methomyl and Bacillus thuringiensis Berliner compared to larvae feeding foliage of the ‘Bragg’ variety.
Abstract: In the laboratory, Heliothis zea (Boddie) larvae that were fed foliage of ED73–371, a genotype resistant to the Mexican bean beetle, Epilachna varivestis Mulsant, weighed less and were more susceptible to methomyl and Bacillus thuringiensis Berliner compared to larvae fed foliage of the ‘Bragg’ variety. No difference was detected in the LD50, of methyl parathion when H. zea larvae were reared on Bragg and ED73–371. Larvae of Pseudoplusia includens (Walker) weighed less and were significantly more susceptible to methyl parathion when fed ED73–371 foliage than when fed Bragg foliage, whereas LD60’s of methomyl and B. thuringiensis were similar on the 2 genotypes.
Percent control of field populations of H. zea was greater in ED73–371 than in Bragg soybeans when plots of each genotype were treated with similar rates of methyl parathion or B. thuringiensis . Fewer larvae were found in untreated plots of ED73–371 than in Bragg, indicating a lower natural population in the resistant soybeans.
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TL;DR: Parasporal crystals of Bacillus thuringiensis Berliner were 30X as toxic to larvae of Ephestia cautella (Walker) as were spores, and the toxicity of spore-crystal mixtures was predictable from the number of crystals in the mixture.
Abstract: Parasporal crystals of Bacillus thuringiensis Berliner were 30X as toxic to larvae of Ephestia cautella (Walker) as were spores. The toxicity of spore-crystal mixtures was predictable from the number of crystals in the mixture. Parasporal crystals were only 3X as toxic as spores to Plodia interpunctella (Hubner) larvae, and a 50:50 mixture of spores and crystals was more toxic than crystals alone.
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TL;DR: Toxicity of Bacillus thuringiensis spores to the tobacco hornworm, Manduca sexta, is described and striking similarity of spores to parasporal crystals is revealed by slope of mortality curves, inhibition of stadial growth, and 50 percent lethal dose values based on protein content.
Abstract: Toxicity of Bacillus thuringiensis spores to the tobacco hornworm, Manduca sexta, is described. The numbers of larvae killed were in relation to spore dry weight. At a surface application of 6.8 ng/cm2, there was an 85 percent survival, but less than 50 percent survived at 68.2 ng/cm2. Striking similarity of spores to parasporal crystals is revealed by slope of mortality curves, inhibition of stadial growth, and 50 percent lethal dose values based on protein content.
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TL;DR: Asporogenic and oligosporogenic mutants of Bacillus thuringiensis can be isolated by streaking the bacteria onto a solid medium, incubating at 42 degrees C, and picking small, raised areas of growth which appear on the streaks after 48 h.
Abstract: Asporogenic and oligosporogenic mutants of Bacillus thuringiensis can be isolated by streaking the bacteria onto a solid medium, incubating at 42 °C, and picking small, raised areas of growth which appear on the streaks after 48 h.
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TL;DR: Surface-layer application of a commercial formulation of Bacillus thuringiensis Berliner was evaluated for controlling Indian meal moths and almond moths in corn stored in 2-m3 (ca. 60-bu) capacity bins and reduced insect feeding damage by >82%, and prevented webbing of the grain surface.
Abstract: Surface-layer application of a commercial formulation of Bacillus thuringiensis Berliner was evaluated for controlling Indian meal moths, Plodia interpunctella (Hubner), and almond moths, Ephestia cautella (Walker), in corn stored in 2-m3 (ca. 60-bu) capacity bins. The bins were artifically infested, and efficacy was monitored by making weekly moth counts, collecting larvae and pupae in strips and spools of corrugated paper, periodically assaying samples of the grain, and evaluating insect feeding damage at the end of the storage season. The test method proved to be satisfactory, and doses of 100, 125, and 150 mg of B. thuringiensis formulation/kg of com in the 10-cm-deep surface layer reduced moth populations by ≥92%, reduced insect feeding damage by >82%, and prevented webbing of the grain surface.
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TL;DR: Mixtures of chlordimeform with Bacillus thuringiensis and Autographa californica nuclear polyhedrosis virus and Pieris rapae granulosis virus with low concentrations of the microbial insecticides were as effective or more effective than the materials used alone at full rates.
Abstract: The efficacy of mixtures of chlordimeform with Bacillus thuringiensis and(or) Autographa californica nuclear polyhedrosis virus and Pieris rapae granulosis virus against Trichoplusia ni and Pieris rapae on the late cabbage was assessed in field plots over four growing seasons. Mixtures of 0.07 kg of chlordimeform/ha (1/8 of the recommended dosage) with low concentrations of the microbial insecticides were as effective or more effective than the materials used alone at full rates. The advantages of such mixtures in pest management are discussed.
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TL;DR: Treatment of gypsy moth, Lymantria dispar (L.), larvae with the parasite Apanteles melanoscelus Ratzeburg and the microbial insecticide Bacillus thuringiensis Berliner yielded a higher mortality than treatment with A. melanOScelus or B. thuringienis alone, but the mortality was less than the sum of the mortalities for the separate treatments.
Abstract: Treatment of gypsy moth, Lymantria dispar (L.), larvae with the parasite Apanteles melanoscelus Ratzeburg and the microbial insecticide Bacillus thuringiensis Berliner yielded a higher mortality than treatment with A. melanoscelus or B. thuringiensis alone. The mortality was, however, less than the sum of the mortalities for the separate treatments. The 7- and 14-day LC50 values for parasitized (97.6 and 50.2 IU of B. thuringiensis per ml of diet, respectively) and for unparasitized (95.3 and 43.4 IU of B. thuringiensis per ml of diet, respectively) larvae showed no significant differences with respect to B. thuringiensis treatment. Mortality due to B. thuringiensis treatment continued up to the 28th day and was dependent on dosage. The majority of deaths due to parasitism alone occurred between the 15th and 28th days. B. thuringiensis treatment of host larvae caused an increase of ca. 3 days in the total development time of A. melanoscelus .
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TL;DR: Two strains of Bacillus thuringiensis and 12 strains of B. cereus were treated with ultraviolet light and mitomycin C and the former agent was the more effective inducer.
Abstract: Forty-eight strains of Bacillus thuringiensis and 12 strains of B. cereus were treated with ultraviolet light and mitomycin C. The former agent was the more effective inducer. Bacillus thuringiensi...
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TL;DR: Analysis of hemolymph proteins using one-dimensional polyacrylamide gel electrophoresis indicated that although some quantitative changes were observed in some experiments, in the faster moving proteins when the infecting agent was B. thuringiensis, they were not consistent enough to support the idea that hemoly mph proteins were either synthesized or used up during the time larvae were responding to the infectious agent.
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01 Aug 1978
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TL;DR: A microbial insecticide thuricide (Potency 30 × 10 9 spores per gram) with Bacillus thuringiensis as active ingredient was bioassayed against twenty six species of forest Lepidoptera belonging to 11 families.
Abstract: ×A microbial insecticide thuricide (Potency 30 × 10 9 spores per gram) with Bacillus thuringiensis as active ingredient was bioassayed against twenty six species of forest Lepidoptera belonging to 11 families.
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TL;DR: Larvae of Sitotraga cerealella (Olivier) were susceptible to Bacillus thuringiensis Berliner incorporated into a ground diet in gelatin capsules and this affected F1 adult emergence but the 2nd generation was significantly reduced.
Abstract: Larvae of Sitotraga cerealella (Olivier) were susceptible to Bacillus thuringiensis Berliner incorporated into a ground diet in gelatin capsules. Doses of 125 and 250 µg of formulated B. thuringiensis /g of diet gave 90–100% control. On wheat, B. thuringiensis did not significantly reduce F1 adult emergence but the 2nd generation was significantly reduced.
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TL;DR: A model for predicting mortality of Schizura concinna larvae on Cercis occidentalis trees following application of Bacillus thuringiensis formulations is based on an estimation of the effective dose and the probability of larval mortality is calculated by means of a multiple logistic dose-response model.
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TL;DR: 1. わが国においては,BT剤の力価検定が可能となり,PXU (Plutella xylostella unit)によって表示することができた。
Abstract: 1. わが国においては,BT剤の力価検定はカイコを用いて行なわれているが,これはただちに害虫に対する力価を示すものではなく,防除対象害虫による力価検定法の確立が必要である。2. 人工飼料で飼育したコナガ幼虫を用い,BT剤の生物検定法について検討した結果,これによる力価検定が可能となり,PXU (Plutella xylostella unit)によって表示することができた。3. PXUおよびBMU (Bombyx mori unit)の相関を調べた結果,高い相関r=0.997(p<0.001)が認められた。BMUの推定値は回帰式Y=0.748X+50.4(X;PXU)から得られた。4. 上記回帰式を用い,実測PXUより推定されるBMUは実測値と非常に近似した。
01 Jan 1978
TL;DR: Commercial preparations of Bacillus thuringiensis are used for plant protection purposes at a !
Abstract: In den USA werden seit 1960 Handelspraparate von Bacillus thuringiensis im grosen Umfange im Pflanzenschutz angewandt. Die Wirksamkeit des Bacillus bleibt dabei auf Lepidopteren beschrankt; er ist deshalb harmlos fur Bienen und Entomophagen. Aufgrund dieser Wirtsspezifitat wurden vom USDA bei der Zulassung keine Wartezeitauflagen gemacht. In Deutschland sind B. thuringiensis-Praparate seit 1964 zugelassen; sie enthalten Sporen und fur Insekten toxische Kristalle und sind frei von Exotoxinen. Die Qualitat der standardisierten Praparate (hinsichtlich der Identitat der, Keime und ihrer hygienischen Unbedenklichkeit) wird von den Herstellern garantiert. Bei der Ausbringung von B. thuringiensis im Feld handelt es sich um eine Erhohung des naturlichen Sporenpegels auf den zu schutzenden Pflanzen. Die Auswirkung dieser Tatsache auf die Umwelt (Ruckstandsfragen und Wasserschutzprobleme) sowie auf Nicht-Zielorganismen werden diskutiert. Obwohl B. thuringiensis sich als ein wirkungsvolles Bekampfungsmittel gegen schadliche Raupen bewahrt, ist es im Gegensatz zu vielen chemischen Insektiziden fur Mensch, Vieh und Umwelt harmlos.
Insect control by Bacillus thuringiensis preparations and their influence on the environment
Commercial preparations of Bacillus thuringiensis are used for plant protection purposes at a !arge scale since 1960 in the USA. The efficiency of the bacillus is limited to Lepidoptera and it is harmless for bees and entomophagous insects. Because of this specificity, the USDA granted B. thuringiensis the status of exemption for a requirement of tolerance for residues. In Germany, preparations based on B. thuringiensis are registered since 1964; they contain spores and crystals (toxic for insects) and are free of exotoxins. The quality of the standardized preparations (identity and safety) are warranted by the producers. - Application of B. thuringiensis in the field causes an enhancement of the natural spore level on the surface of plants to be protected. The influence on the environment (with regard to problems of residues and water protection) are discussed. - In spite of a good efficacy in its action against several noxious caterpillars the use of B. thuringiensis is harmless for man, animals and their environment in contrast to many chemical insecticides.