INSECTICIDAL PROPERTIES of Bacillus thuringiensis var. israelensis. I. THE ACTIVITY SPECTRUM OF A LARVICIDAL PREPARATION BASED ON INDUSTRIAL STRAIN 7-1/23A

Ermolova, V.P.; Grishechkina, S.D.; Rakhman, Adi; Antonets, Kirill S.; Belousova, Maria; Yakhno, V. V.; Nizhnikov, Anton A.

doi:10.15389/agrobiology.2019.6.1267eng

Cited by 2 publications

(2 citation statements)

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“…Being large and widely used for dipteran pest control, serovar israelensis was selected to assess the differences in the proteomic profiles between the vegetative cells and sporulating culture. Apart from the virulent strain 800/3 previously reported to harbor cry4 and cry11 genes and active against the insects of Diptera order [ 26 , 27 ], spores of an avirulent descendant strain, 800/3-15, were analyzed in order to assess the differences in the virulence factors production ( Figure 1 a). To ensure that the cultures were sampled at the proper time points, absorption profiles of the growing cultures were analyzed ( Figure 1 b).…”

Section: Resultsmentioning

confidence: 99%

“…A major drawback of the technique used lies in the absence of any identified three-domain Cry proteins. All three strains have been previously demonstrated to possess Cry-encoding genes [ 26 , 27 ]. A plausible explanation for this lack comes from low solubilization of Cry toxins in traditional protein extraction buffers [ 11 ], which may require additional rounds of protein solubilization [ 10 ].…”

Section: Discussionmentioning

confidence: 99%

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The Distribution of Several Genomic Virulence Determinants Does Not Corroborate the Established Serotyping Classification of Bacillus thuringiensis

Shikov

Malovichko

Lobov

et al. 2021

IJMS

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Bacillusthuringiensis, commonly referred to as Bt, is an object of the lasting interest of microbiologists due to its highly effective insecticidal properties, which make Bt a prominent source of biologicals. To categorize the exuberance of Bt strains discovered, serotyping assays are utilized in which flagellin serves as a primary seroreactive molecule. Despite its convenience, this approach is not indicative of Bt strains’ phenotypes, neither it reflects actual phylogenetic relationships within the species. In this respect, comparative genomic and proteomic techniques appear more informative, but their use in Bt strain classification remains limited. In the present work, we used a bottom-up proteomic approach based on fluorescent two-dimensional difference gel electrophoresis (2D-DIGE) coupled with liquid chromatography/tandem mass spectrometry(LC-MS/MS) protein identification to assess which stage of Bt culture, vegetative or spore, would be more informative for strain characterization. To this end, the proteomic differences for the israelensis-attributed strains were assessed to compare sporulating cultures of the virulent derivative to the avirulent one as well as to the vegetative stage virulent bacteria. Using the same approach, virulent spores of the israelensis strain were also compared to the spores of strains belonging to two other major Bt serovars, namely darmstadiensis and thuringiensis. The identified proteins were analyzed regarding the presence of the respective genes in the 104 Bt genome assemblies available at open access with serovar attributions specified. Of 21 proteins identified, 15 were found to be encoded in all the present assemblies at 67% identity threshold, including several virulence factors. Notable, individual phylogenies of these core genes conferred neither the serotyping nor the flagellin-based phylogeny but corroborated the reconstruction based on phylogenomics approaches in terms of tree topology similarity. In its turn, the distribution of accessory protein genes was not confined to the existing serovars. The obtained results indicate that neither gene presence nor the core gene sequence may serve as distinctive bases for the serovar attribution, undermining the notion that the serotyping system reflects strains’ phenotypic or genetic similarity. We also provide a set of loci, which fit in with the phylogenomics data plausibly and thus may serve for draft phylogeny estimation of the novel strains.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

The Distribution of Several Genomic Virulence Determinants Does Not Corroborate the Established Serotyping Classification of Bacillus thuringiensis

Shikov

Malovichko

Lobov

et al. 2021

IJMS

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Technology of production of biopesticides based on Bacillus thuringiensis

Bezusov¹,

Krutyakova²,

Myroshnichenko³

et al. 2021

Food.Res

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Subject of research. Biopesticides are based on live cultures of specially selected beneficial microorganisms with controlled properties. They have a pronounced phytoprotective and stimulating effect, thus providing effective prevention and protection of plants from diseases. The obtained biological product increases productivity, improves the quality and structure of the crop, does not accumulate in plants, which allows to obtain environmentally friendly agricultural products and does not harm the environment. Among the large number of bacteria, as a source of microbiological insecticide is Bacillus thuringiensis, which infects lepidopteran pests and leads to their death. Preparations based on this strain are effective when used in low concentrations of solutions. The Bacillus thuringiensis strain produces several toxins with insecticidal action, including β-exotoxin and δ-endotoxin. Toxic effect is manifested and leads to paralysis of the intestinal tract of parasites. Preparations β-exotoxin and δ-endotoxin are obtained by culturing Bacillus thuringiensis bacteria in a liquid medium. The scientific work proposes a method of industrial production using by-products of vegetable raw materials, which makes it economically feasible to use such substrates. The purpose of the study is the development of technology, formulation of nutrient medium, process parameters for the cultivation of bacteria of the genus Bacillus thuringiensis and obtaining a culture fluid containing substances of the class of biopesticides. Methods. Standard and generally accepted methods of research of bioproducts in biotechnology. The formation of bioinsecticides was established by hydrolysis methods, followed by determination of the component of β-exotoxin – ribose, the formation of octagonal crystals of exotoxin – by microscopic method. Research results. Three variants of nutrient media, which include yeast-polysaccharide complex: corn flour, corn oil, yeast autolysate were developed. The parameters of the bacterial cultivation process were studied. The final product is a paste or powder with a titer of 35 .109 spores in 1 g of the bioproduct. Scope of research results. Microbiological preparations based on Bacillus thuringiensis are highly specific and act only on insect larvae from the classes Lepidoptera and Diptera. The resulting biopesticide can be used against pests of a wide range of vegetable and fruit crops.

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INSECTICIDAL PROPERTIES of Bacillus thuringiensis var. israelensis. I. THE ACTIVITY SPECTRUM OF A LARVICIDAL PREPARATION BASED ON INDUSTRIAL STRAIN 7-1/23A

Cited by 2 publications

References 31 publications

The Distribution of Several Genomic Virulence Determinants Does Not Corroborate the Established Serotyping Classification of Bacillus thuringiensis

The Distribution of Several Genomic Virulence Determinants Does Not Corroborate the Established Serotyping Classification of Bacillus thuringiensis

Technology of production of biopesticides based on Bacillus thuringiensis

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