The Effect of Gamma Sterilization on the Insecticidal Toxicity of Engineered and Conventional &lt;I&gt;Bacillus thuringiensis&lt;/I&gt; Strains

Sun, Shifeng; Fan, Jing; Cheng, Zhongshan; Cai, Yi; Li, Guanghong; Pang, Yi

doi:10.1603/ec12192

Cited by 6 publications

(6 citation statements)

References 34 publications

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“…It reduced by 20 and 29% for the pesticide irradiated at 20 and 25 kGy, respectively. These results are consistent with other research that irradiation at a dose of 20-25 kGy caused a 20-30% reduction in the effectiveness of Bt-based pesticide against mosquito larvae and the reduction of toxicity of Bt by radiation follows a rather linear model [5]. According to Sun et al, the insecticidal effectiveness of Bt products against lepidoptera pests did not reduce, but their toxicities against mosquito were significantly reduced by gamma irradiation [5].…”

Section: B Estimation Of Radiation Effect On the Toxicity Of Vbt Pesticidesupporting

confidence: 91%

“…From these results, the minimum dose required to sterilize the Bt spores in VBT was estimated as about 20 kGy, similar to the other results [4,12]. In studies on the radiation sensitivities of some Bacillus thuringiensis strains, Sun et al reported that 9, 12, 15 and 19 kGy were effective dose for killing 4 types of Bt spores particularly WP, HD-1, TnY and TnX spores, respectively [5]. The radiation sensitivities among the Bt strains depend on their physiological characteristics and their abilities to recover from radiation injury.…”

Section: Nd: Not Detectedsupporting

confidence: 80%

“…Therefore, the number of Bt living spores in bio-pesticides must be controlled. In Germany, only the Bt products that do not contain living bacilli or spores can be applied [5]. Since spores are highly resistant to heat, radiation and chemical, the inactivation of bacterial spores has been considered as a challenge for human health, environmental quality and food safety [6].…”

Section: Introductionmentioning

confidence: 99%

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Study on using gamma radiation to inactivate Bacillus thuringiensis spores in biopesticide

Nguyễn¹,

Nguyen²,

Tran³

et al. 2017

Nucl. Sci. and Tech.

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Bacillus thuringiensis (Bt) produces different types of toxin that have potent and specific insecticidal activity. In recent years, Bt toxins have been used as the safe biological control agents to protect crops replacing for chemical insecticides. Bt-based biopesticides that have been commercialized as the alternative products to control pests and insects for sustainable agriculture, contain toxicity crystals and a significant number of spores that affects to the soil microflora. These uncontrollable changes may contaminate the cultivation soil, and eventually cause adverse effects to human and animal health. Therefore, the living cells and spores existing in the Bt-biopesticides should be controlled. This study evaluates the effects of gamma radiation on spore viability, germination and growth of the existing spores after spraying on the soil and the insecticidal effectiveness of a Bt-based biopesticide (VBT) against lepidoptera larvae. We attempted to identify the optimal dose that couldinactivate Bt spores but the toxicity of Bt still retain highly. The results revealed that the dose of 20 kGy is enough to control all living cells and spores in the product that consists of approximately 5.2 × 107 spores in the initial VBT. Though the growth of existing spores after spraying on the soil reduced by 85% or more by irradiation, their insecticidal activity against Heliothis armigera larvae reduced by 20-30% only as compared to that of the initial VBT. It suggested that gamma irradiation can be applied as useful way to control the living cells and spores existing in the commercial Bt-based bio-pesticides, and the radiation dose of 20 kGy is enough to kill all spores in VBT, but still kept its insecticidal effect for Heliothis armigera larvae

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Section: B Estimation Of Radiation Effect On the Toxicity Of Vbt Pesticidesupporting

confidence: 91%

Section: Nd: Not Detectedsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

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Study on using gamma radiation to inactivate Bacillus thuringiensis spores in biopesticide

Nguyễn¹,

Nguyen²,

Tran³

et al. 2017

Nucl. Sci. and Tech.

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“…More recently, Sun et al. () reported that in the radiation dosage range of 10–15 kGy, no viable spore formation and no significant reduction in the efficiency of B. thuringiensis against lepidopteran larvae were observed, demonstrating that the use of gamma radiation is effective to inactivate the spores of engineered B. thuringiensis strains while preserving toxicity against the target insect larvae.…”

Section: Assessmentmentioning

confidence: 99%

Risks for public health related to the presence of Bacillus cereus and other Bacillus spp. including Bacillus thuringiensis in foodstuffs

Allende¹,

Bolton²,

Chemaly³

et al. 2016

EFS2

135

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The Bacillus cereus group, also known as B. cereus sensu lato, is a subdivision of the Bacillus genus that consists of eight formally recognised species: B. cereus sensu stricto, B. anthracis, B. thuringiensis, B. weihenstephanensis, B. mycoides, B. pseudomycoides, B. cytotoxicus and B. toyonensis. The current taxonomy of the B. cereus group and the status of separate species mainly rely on phenotypic characteristics. Bacillus thuringiensis strains display a similar repertoire of the potential virulence genes on the chromosome as B. cereus sensu stricto strains and it has been shown that these genes can also be actively expressed in B. thuringiensis strains. Bacillus cereus and B. thuringiensis strains are usually not discriminated in clinical diagnostics or food microbiology. Thus, the actual contribution of the two species to gastrointestinal and non-gastrointestinal diseases is currently unknown. Most cases of food-borne outbreaks caused by the B. cereus group have been associated with concentrations above 10 5 CFU/g. However, cases of both emetic and diarrhoeal illness have been reported involving lower levels of B. cereus. The levels of B. cereus that can be considered as a risk for consumers are also valid for B. thuringiensis. There is no evidence that B. thuringiensis has the genetic determinants for the emetic toxin cereulide. The Panel has recommended the application of whole genome sequencing to provide unambiguous identification of strains used as biopesticides and the detailed characterisation of outbreak strains allowing discrimination of B. thuringiensis from B. cereus. Data gaps include: dose-response and behavioural characteristics of B. cereus group strains and specifically of B. thuringiensis. Field studies after application of B. thuringiensis biopesticides are needed to enable the establishment of pre-harvest intervals. for the preparatory work on this scientific output and EFSA staff members: Maria Teresa da Silva Felicio, Giusi Amore, Emmanouil Chantzis, Laszlo Bura and Frederique Istace for the support provided to this scientific opinion. Suggested citation: EFSA BIOHAZ Panel (EFSA Panel on Biological Hazards), 2016. Scientific opinion on the risks for public health related to the presence of Bacillus cereus and other Bacillus spp. including

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“…SP7 isolate has spherical crystal protein form, SP15 from observation shows spherical crystal protein form. Other observation showed crystal proteins of spherical shape 15,16,17 . …”

Section: Figure 1compound Light Microscopephotograph Of (A) Sp7 Isolmentioning

confidence: 93%

A Study on A LocalBacillus thuringiensis SP7 To Control Mosquito Larvae of Aedes aegypti

Nasution¹,

Suryanto²,

Siregar³

2018

IJCTR

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: Bacillus thuringiensis(Bt)is a gram-positive bacteria, spore-forming, and producing crystal proteinsused as bioinsecticides. The purpose of the study was to know potential of local isolates of Bt in controlling mosquito larva of Aedes aegypti.Isolation of Bt was conducted from soil samples of Tongkoh Forest, Brastagi, North Sumatra, Indonesia. Bt spore and crystal protein were observed using compound light microscope and further using scanning electron microscope. Two suspected isolates were choosen based on their morphological and biochemical characteristic. Further identification was done using their 16S rRNA gene. To know Bt growth pattern in inexpensive C and N-source, Bt isolate was grown in culture media with molasses and urea as C and N sources. To assay on Bt isolate to control mosquito, larva instar 3 of mosquito were put in 50 ml of test media of concentration of 10, 20, 30, 40, and 50% of Bt culture in plastic cup.Observation was done after 24 hrs. Two isolates SP7 and SP15 showed to have morphological and biochemical characteristicsimilar tothat of Bt. Identification based on 16S rRNA gene sequence showed that SP7 and SP15 were closed to B. thuringiensis strain MCCC 1A00395 with similarity of 99%. Since two Bt isolates seemed to be similar to B. thuringiensis strain MCCC 1A00395, SP7 was choosen for further study. SP7 reached its maximum growth at 30 hrsof incubationtime with cell number of 17.01 log CFU/ml in culture media with molasses and urea as C and N sources. It showed to kill up to 97.5% mosquito larvae atconcentration of 50% bacterial culture.

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The Effect of Gamma Sterilization on the Insecticidal Toxicity of Engineered and Conventional <I>Bacillus thuringiensis</I> Strains

Cited by 6 publications

References 34 publications

Study on using gamma radiation to inactivate Bacillus thuringiensis spores in biopesticide

Study on using gamma radiation to inactivate Bacillus thuringiensis spores in biopesticide

Risks for public health related to the presence of Bacillus cereus and other Bacillus spp. including Bacillus thuringiensis in foodstuffs

A Study on A LocalBacillus thuringiensis SP7 To Control Mosquito Larvae of Aedes aegypti

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