cry1 genes from Bacillus thuringiensis: specificity determination and implications for primer design

Some pest management programs employ PCR to identify cry1 genes from Bacillus thuringiensis to predict bacterial toxicity towards different insect pests. However, due to changes on the mode of action of the Cry proteins, new primers had to be designed to detect the new genes. Therefore, an 'in-silico' study of genetic sequences from five cry1 subclasses was carried out and characterized by molecular tools. The design of new primers allows for more precise selection of B. thuringiensis isolates, helping to better direct the programs employing biological control.

Xylanase production by Bacillus circulans D1 using maltose as carbon source

Bacillus circulans D1 is a good producer of extracellular thermostable xylanase. Xylanase production in different carbon sources was evaluated and the enzyme synthesis was induced by various carbon sources. It was found that D-maltose is the best inducer of the enzyme synthesis ( 7.05 U/ mg dry biomass at 48 h), while D-glucose and D-arabinose lead to the production of basal levels of xylanase. The crude enzyme solution is free of cellulases, even when the microorganism was cultivated in a medium with D-cellobiose. When oat spelt xylan was supplemented with D-glucose, the repressive effect of this sugar on xylanase production was observed at 24 h, only when used at 5.0 g/ L, leading to a reduction of 60% on the enzyme production. on the other hand, when the xylan medium was supplemented with D- xylose ( 3.0 or 5.0 g/ L), this effect was more evident ( 80 and 90% of reduction on the enzyme production, respectively). Unlike that observed in the xylan medium, glucose repressed xylanase production in the maltose medium, leading to a reduction of 55% on the enzyme production at 24 h of cultivation. Xylose, at 1.0 g/ L, induced xylanase production on the maltose medium. on this medium, the repressive effect of xylose, at 3.0 or 5.0 g/ L, was less expressive when compared to its effect on the xylan medium.

Anti-Angiogenic Effects of the Superantigen Staphylococcal Enterotoxin B and Bacillus Calmette-Guerin Immunotherapy for Nonmuscle Invasive Bladder Cancer

Purpose: We compared and characterized the effects of intravesical bacillus Calmette-Guerin and/or staphylococcal enterotoxin B for nonmuscle invasive bladder cancer.Materials and Methods: A total of 75 female Fisher 344 rats were anesthetized. of the rats 15 received 0.3 ml saline (control) and 60 received 1.5 mg/kg MNU (N-methyl-n-nitrosourea) intravesically every other week for 6 weeks. The rats were divided into 5 groups. The MNU and control groups received 0.3 ml saline. The bacillus Calmette-Guerin group received 10(6) cfu bacillus Calmette-Guerin. The staphylococcal enterotoxin B group received 10 mu g/ml staphylococcal enterotoxin B. The bacillus Calmette-Guerin plus staphylococcal enterotoxin B group received the 2 treatments simultaneously. Each group was treated intravesically for 6 weeks. At 15 weeks all bladders were collected for histopathological and immunological evaluation, and Western blot.Results: Papillary carcinoma (pTa) and high grade intraepithelial neoplasia (carcinoma in situ) were more common in the MNU group. Papillary hyperplasia was more common in the bacillus Calmette-Guerin and enterotoxin groups. Flat hyperplasia was more common in the bacillus Calmette-Guerin plus enterotoxin group. No significant toxicity was observed. The apoptosis and cellular proliferation indexes decreased in the bacillus Calmette-Guerin, enterotoxin and bacillus Calmette-Guerin plus enterotoxin groups compared to the MNU group. Intensified vascular endothelial growth factor, matrix metalloproteinase-9, Ki-67 and insulin-like growth factor receptor-1 immunoreactivity was verified in the MNU group, moderate in the bacillus Calmette-Guerin and enterotoxin groups, and weak in the bacillus Calmette-Guerin plus enterotoxin and control groups. In contrast, intense endostatin immunoreactivity was verified in the control and bacillus Calmette-Guerin plus enterotoxin groups.Conclusions: Bacillus Calmette-Guerin and staphylococcal enterotoxin B showed similar anti-angiogenic effects. Bacillus Calmette-Guerin plus enterotoxin treatment had additional activity compared to that of monotherapy. It was more effective in restoring apoptosis and balancing cellular proliferation, and it correlated with increased endostatin, and decreased vascular endothelial growth factor, matrix metalloproteinase-9, Ki-67 and insulin-like growth factor receptor-1 reactivity.

Interaction Between the Predator Podisus nigrispinus (Hemiptera: Pentatomidae) and the Entomopathogenic Bacteria Bacillus thuringiensis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Bacillus thuringiensis development from 1971 to 1996: Cases of a research group in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Survival and conjugation of Bacillus thuringiensis in a soil microcosm

The survival and conjugation ability of sporogenic and asporogenic Bacillus thuringiensis strains were investigated in broth, in non-amended sterile clay soil monoculture and in mixed soil culture. The 75 kb pHT73 plasmid carrying an erythromycin resistance determinant and a cry1Ac gene was transferred in mating broth and soil microcosm. Survival of strains was assessed in soil monoculture and in mixed soil culture for up to 20 days. Sporogenic strains rapidly formed viable spores which were maintained until the end of the experiment. The asporogenic strains were no longer recovered after 8 days of incubation. This study shows that the environmental impact of asporogenic B. thuringiensis strains is lower than that of sporogenic B. thuringiensis strains. Thus, the use of asporogenic strains may significantly reduce any potential risk (gene transfer, soil and plant contamination) due to the dissemination of B. thuringiensis-based biopesticides in the environment. Copyright (C) 2000 Federation of European Microbiological Societies.

Transference of a crystal protein gene from bacillus thuringiensis and its expression in bradyrhizobium sp. cells

The plasmid pHT409 that harbours the cryIA(a) gene for the production of a δ-endotoxin (crystal protein) from Bacillus thuringiensis was transferred into Bradyrhizobium sp. A conjugal transfer system aiming to introduce the plasmid into the Bradyrhizobium sp. host from colonies of an Escherichia coli donor strain (DH5α

ABO, Lewis, secretor and non-secretor phenotypes in patients infected or uninfected by the Helicobacter pylori bacillus

CONTEXT: Epidemiological studies have demonstrated higher frequencies of the O blood group and the non-secretor phenotype of ABH antigens among patients suffering from peptic ulcers. Since Helicobacter pylori has been established as the main etiological factor in this disease, controversies about the associations of the ABO and Lewis blood group phenotypes and secretor and non-secretor phenotypes in relation to susceptibility towards infection by this bacillus have been presented. OBJECTIVE: To verify the frequencies of ABO, Lewis blood group phenotypes, secretor and non-secretor phenotypes in patients infected or uninfected by H. pylori. DESIGN: Cross-sectional study. SETTING: Outpatient clinic. PARTICIPANTS: One hundred and twenty patients with dyspeptic symptoms who underwent endoscopy. MAIN MEASUREMENTS: ABO and Lewis blood group phenotypes were determined by a standard hemagglutination test and the secretor and non-secretor phenotypes were evaluated by saliva samples using the inhibitor hemagglutination test. RESULTS: The diagnosis of infection, made via breath and urea tests and confirmed using polymerase chain reaction (PCR) in gastric biopsy fragments, showed the presence of H. pylori in 61.7% of the patients and absence in 38.3%. The differences between the frequencies of the ABO blood group phenotypes among infected (A 27.0%; B 12.2%; AB 4.0% and O 56.8%) and uninfected patients (A 58.7%; B 13.0%; AB 4.3% and O 24.0%) were significant. The Lewis blood type, secretor and non-secretor phenotypes showed homogeneous distribution between the groups of patients analyzed. CONCLUSIONS: Our results suggest that the infection of H. pylori can be related to ABO blood groups but not to the Lewis blood group nor to secretor and non-secretor phenotypes. Copyright©2002, Associação Paulista de Medicina.

Effect of Bacillus circulans D1 thermostable xylanase on biobleaching of eucalyptus kraft pulp

The alkalophilic Bacillus circulans D1 was isolated from decayed wood. It produced high levels of extracellular cellulase-free xylanase. The enzyme was thermally stable up to 60°C, with an optimal hydrolysis temperature of 70°C. It was stable over a wide pH range (5.5-10.5), with an optimum pH at 5.5 and 80% of its activity at pH 9.0. This cellulase-free xylanase preparation was used to biobleach kraft pulp. Enzymatic treatment of kraft pulp decreased chlorine dioxide use by 23 and 37% to obtain the same kappa number (κ number) and brightness, respectively. Separation on Sephadex G-50 isolated three fractions with xylanase activity with distinct molecular weights.

Diversity of cry genes and genetic characterization of Bacillus thuringiensis isolated from Brazil

Two hundred and eighteen Bacillus thuringiensis isolates from Brazil were characterized by the presence of crystal protein genes by PCR with primers specific to different cry and cyt genes. Among these isolates, 95 were selected according to their geographic origin for genetic characterization with the 16S rRNA gene, RAPD, and plasmid profile. Isolates containing cryl genes were the most abundant (48%) followed by the cry11 and cyt (7%) and cry8 genes (2%). Finally, 40.3% of the isolates did not produce any PCR product. The plasmid profile and RAPD analysis showed a remarkable diversity among the isolates of B. thuringiensis not observed in the 16S rRNA gene. These results suggest that the genetic diversity of B. thuringiensis species results from the influence of different ecological factors and spatial separation between strains generated by the conquest of different habitats.

Production of CGTase by a bacillus Alkalophilic CGII strain isolated from wastewater of a manioc flour industry

GCTase production by a new strain of Bacillus alkalophillc CGII isolated from Brazilian wastewater of manioc flour industry was examined. The growth medium used was composed by 1.5% starch, 1.5% nitrogen and 1% Na 2CO3. Higher activity was obtained with starch, maltodextrin and galactose. When glucose was added to the medium, no enzyme production was observed. High enzyme activity and growth were reached when aeration was increased (88.6 U/mL). The enzyme characterization showed an optimum pH and temperature 8.0 and 55°C for starch hydrolyses, respectively. Mg+ and Ca++ showed small activation; however, Hg + and Cu+ showed a strong enzyme inhibition.

Interaction of Bacillus thuringiensis Cry1 and Vip3A proteins with Spodoptera frugiperda midgut binding sites

Vip3Aa, Vip3Af, Cry1Ab, and Cry1Fa were tested for their toxicities and binding interactions. Vip3A proteins were more toxic than Cry1 proteins. Binding assays showed independent specific binding sites for Cry1 and Vip3A proteins. Cry1Ab and Cry1Fa competed for the same binding sites, whereas Vip3Aa competed for those of Vip3Af. Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Cyclodextrin glycosyltransferase production by the Bacillus sp., subgroup alcalophilus using a central composite design

Cyclodextrin glycosyltransferase (CGTase) activity was produced by the Bacillus sp., subgroup alcalophilus in a culture medium containing cassava starch. A central composite design and response surface methodology were used to study the influence of carbon source (cassava starch), nitrogen sources (yeast extract and tryptone) and sodium carbonate in the production medium. Assays were performed in 300 mL Erlenmeyer flasks containing 100 mL of production medium maintained in a shaker at 150 rpm at 35±1°C for 72 h of fermentation. The independent variables [0.75% cassava starch, nitrogen sources (0.375% yeast extract and 0.375% tryptone) and 1% Na2CO3] produced an enzyme activity of 96.07 U mL-1.© Academic Journals Inc.

Bacillus Thuringiensis mutant increase activity against Apodoptera Frugiperda larvae

Bacillus thuringiensis is a Gram-positive bacterium which main characteristic is the production of Cry proteins, that is toxic to some insects. These proteins, when ingested by susceptible insects, become active causing their death. In nature, it is possible to found B. thuringiensis strains which produce these proteins, but they differ in productivity (some of these isolates are more productive then others), and as to the toxicity levels of the produced proteins. Two B. thuringiensis strains that were highly effective against Spodoptera frugiperda larvae were chosen to verifying genetic mutation implication on Cry proteins productivity. One strain with a prolific spores production, while the other one only produced small amounts of spores. A genomic mutant library of these two isolates was, separately, constructed by genome Tn-5 transposon random insertion. Data analysis showed that mutation had a direct effect on the spores production, inducing an increase as well as a decrease in the production, according to the different strain observed. These results indicate, for the first time, that it is possible to use the described technique with B. thuringiensis, as well as the possibility to genetically breeding this bacteria. Another possibility introduced here is the possibility to do functional genetic studies mediated by mutagenesis in this bacterium.