Search results for "Bacillus"
showing 10 items of 774 documents
Environmental distribution and diversity of Bacillus thuringiensis in Spain.
1998
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-crystal mixtures revealed diverse populations of B. thuringiensis which were differentiated in at least 92 distinct protein profiles. Serological identification also showed great diversity among the S…
Characterization of Bacillus thuringiensis ser. balearica (Serotype H48) and ser. navarrensis (serotype H50): two novel serovars isolated in Spain.
2000
The novel strains of Bacillus thuringiensis PM9 and NA69, isolated from soil samples in Spain, were classified and characterized in terms of their crystal proteins, plasmid profile, cry genes content, and their toxicological properties against several species of Lepidoptera, Coleoptera, and Diptera. Both strains share morphological and biochemical characteristics with previously described B. thuringiensis strains, although their unique H antigens identify them as two new serotypes. Two new serovar names, B. thuringiensis serovar balearica (H serotype 48) and B. thuringiensis serovar navarrensis (H serotype 50) are proposed for the type strains PM9 and NA69, respectively.
A Bacillus thuringiensis strain producing epizootics on Plodia interpunctella: A case study
2012
Abstract After several disease outbreaks in laboratory cultures of pyralid moths in Tabriz University, Iran, during 2004 and 2005, a new Bacillus thuringiensis aizawai strain EF495116 (BTA) was isolated from a dead Plodia interpunctella larva. A complete characterization of the strain was performed, including serological identification, protein and plasmid pattern determination, a PCR-based identification of virulence-related genes, nucleotide sequence analysis of the 16S rDNA and gyrB genes (in order to find out relationships between the species with other virulent Bacillus pathogens), and biological activity assays. These studies revealed that BTA produced a major parasporal protein band …
Tomato leaf miner Tuta absoluta (Meyrick,1917) (Lepidoptera: Gelechiidae) The old and new challenge
2014
The term Phytosanitary exists within many of the modern and old scientific terms such as: organic farming, plant protection, integrated pest management, national and international movement of plant germplasm, biosecurity, good agricultural practices and others. There are many aspects within those related terms. All those terms have common interests of which the pests' risk be avoided and the environmental health is achieved. Consequently preventive measures, precaution measures and effective testing procedures are required. The study problem is the pest Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), the Tomato leaf miner, this pest is one of the most devastating pests affecting T…
Susceptibility of ostrinia nubilalis to bacillus thuringiensis var. kurstaki
2003
Baseline susceptibility of European corn borer larvae, Ostrinia nubilalis (Hübner), to a commercial formulation of Bacillus thuringiensis var. kurstaki was determined for different strains in 7 geographic locations in the corn area of North Italy (Po Valley). For the bioassay 7 different doses, raised on a meredic diet, were used and the data was analysed with the Probit analysis. Differences in the susceptibility among the northern Italian populations of O. nubilalis were recorded, which can be attributed to natural variability. The ECB collected near Como and Torino was the most susceptible, respectively with LC50 of 0.23 and 0.57 mg/ml. The most tolerant ones were the larvae coming from …
Susceptibility to BT of wild lepidopteran species in Nature Reserve in Sicily
2010
A wide range of crop plants and trees have been transformed with genes derived from the soil bacterium Bacillus thuringiensis (Bt) to express insecticidal proteins (insect-resistant Bt plants). Whereas the adoption of Bt plants constitutes one of the most common uses of transgenic plants in agriculture, the environmental benefits and risks remain an issue. To preserve the natural reserve and their fauna UE proposed that in future the Member State specify a minimum separation distance of metres between fields of GM plants and nature reserves or to forbid cultivation of GM plant in particular area based on scientific data. Natural reserve in Sicily have many endemism and rare species so next …
An alternative set of test to bioassay for bioinsecticides
2010
The development of an assay to determine insecticidal properties for either biological and conventional plant protection products plays an important role on the early screening of potential pathogens or derived toxins candidates. The standard methods for the evaluation it has been by bioassay, especially determination of LD50 or LC 50 requiring the use of relatively large numbers of insects and toxin tests. There are several problems connected with these bioassays: availability of insects and in the right life stage, mass producing the candidate species, preparation, reproducibly and costs relative to intensive manpower. These aspects are really important especially when bio-insectides shou…
Bacillus thuringiensis treatment alters larval growth, hemocytes and modulation of Hsp70 in Rhynchophorus ferrugineus
2011
To study the pathogen-host relationship, we used the model of the entomopathogenic bacterium Bacillus thuringiensis (Bt) and Rhynchophorus ferrugineus, a quarantine pest that attacks the palm trees. In particular, we focused on the Bt stress-induced infections. We studied the effect of Bt on larval growth, on hemocytes and on the expression of the heat shock proteins (Hsp70). HSPs are rapidly synthesized in the cells after a stress exposition including pathogens. The Hsp70 was evaluated in the supernatant of the hemocyte lysate (HLS) obtained from larvae fed with Bt. This is the first time that the presence of Hsp70 has been recorded in R. ferrugineus. Bt has negative effects on larval grow…
Use of biorational insecticides for the control of Tuta absoluta (Meyrick) infestations on open field tomato
2012
Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), the tomato leaf miner, is one of the most devastating pests affecting tomato crops in Italy. Management of T. absoluta was assessed in open-field tests using three biorational insecticides, Azadirachtin, Bacillus thuringiensis var. kurstaki, and Beauveria bassiana, and a combination of three synthetic insecticides, Emamectin, Indoxacarb and Metaflumizone, as a control treatment. Our results showed that only the combination of Azadirachtin – B. thuringiensis was able to reduce the impact of tomato leaf miner on the fruit’s marketable production similarly to the control treatment. This finding suggests that biorational insecticides are a goo…
Antimycotic activity of Bacillus amyloliquefaciens against fungi of vineyards soil origin
2009
Preliminary investigations on grapevines (cv Catarratto) with symptoms of “esca” allowed the isolation of different bacterial colonies (Alfonzo et al, 2009). A Gram-positive, spore forming isolate, able to inhibit fungal growth, was subjected to identification. On the basis of the whole 16S rRNA gene sequence, it showed a similarity of 99% with Bacillus amyloliquefaciens. There are numerous reports on the antagonistic activity of this species towards several phytopathogenic microorganisms. For this reason, the potential of the bacterial strain against the fungi commonly associated to the soil of vineyards (Alternaria alternata, Aspergillus ochraceus, Aspergillus carbonarius, Cladosporium cl…