Thuricin 4AJ1, produced by Bacillus thuringiensis strain 4AJ1, showed inhibition activity against Bacillus cereus 0938 and ATCC 10987. It began to appear in the stationary phase and reached its maximum activity level of 209.958 U at 18 h against B. cereus 0938 and 285.689 U at 24 h against B. cereus ATCC 10987. Tricine-SDS-PAGE results showed that the partly purified thuricin 4AJ1 was about 6.5 kDa. The molecular weights of the known B. thuringiensis bacteriocins and the ones obtained by the two mainstream websites for predicting bacteriocins were inconsistent with the size of the thuricin 4AJ1, indicating that the bacteriocin obtained in this study may have a novel structure. Based on the biochemical properties, the thuricin 4AJ1 activities increased after treatment with proteinase K and lipase II, and were not affected by a-amylase, catalase, α-chymotrypsin VII and α-chymotrypsin II. It was heat tolerant, being active up to 90º C. In the pH 3-10 range, it maintained most of its activity. Finally, the sensitivity of the strain 4AJ1 to commonly used antibiotics was tested. In view of its stability and antibacterial activity, thuricin 4AJ1 may be applied as a food biopreservative.
- MeSH
- antibakteriální látky farmakologie MeSH
- Bacillus cereus účinky léků MeSH
- Bacillus thuringiensis chemie metabolismus MeSH
- bakteriociny chemie izolace a purifikace farmakologie MeSH
- elektroforéza v polyakrylamidovém gelu MeSH
- molekulová hmotnost MeSH
- potravinářská mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
Bacillus thuringiensis (Bt) is efficient, strongly specific, and avirulent to humans, making it one of the most popular biopesticides in the world. Bt LLP29 is a mosquitocidal strain that was first isolated from Magnolia denudata. To understand its molecular mechanism against mosquitoes, the genome of Bt LLP29 was sequenced and annotated in this study. The LLP29 genome was found to have a total length of 5.99 Mb, with an average G + C content of 35.21%. A total of 6107 coding sequences were also detected, together with 42 rRNAs and 124 tRNAs and 135 other RNAs. With the help of annotation databases, including GO, COG, KEGG, Nr and Swiss-Prot, most unigene functions were identified. At the same time, a collinear analysis was performed on the genome of LLP29. There were also some virulence genes detected, including cry, chitinase, zwittermicin and vip.
A novel Bacillus thuringiensis (Bt) bacteriocin BtCspB, active against a food-borne pathogen Bacillus cereus, was identified and purified by a traditional four-step chromatographic process with low yield (44.5 µg/L) in our lab previously. The aim of this study was to dramatically increase its yield by heterologous expression of BtCspB. The BtCspB gene from Bt BRC-ZYR2 was successfully heterologously expressed in Escherichia coli BL21 (DE3). Affinity chromatography was used to obtain the pure BtCspB up to 20 mg/L. The purified BtCspB showed a MIC value of 12.5 µg/mL and a MBC value of 50.0 µg/mL against Bacillus cereus ATCC 10987. The bacteriocin activity of BtCspB against B. cereus ATCC 10987 was further directly detected in a gel-overlay assay. The anti-B. cereus activity, however, was lower than the bacteriocin purified by the traditional four-step chromatographic process probably because of structural modifications. Compared with the traditional method, the yield of the bacteriocin by heterologous expression increased by 449 times, and the purification step was dramatically simplified, which laying a foundation for the industrial production of this novel cold-shock protein-like bacteriocin BtCspB active against B. cereus.
- MeSH
- Bacillus cereus účinky léků MeSH
- Bacillus thuringiensis genetika metabolismus MeSH
- bakteriální proteiny genetika izolace a purifikace farmakologie MeSH
- bakteriociny farmakologie MeSH
- Escherichia coli genetika růst a vývoj MeSH
- mikrobiální testy citlivosti MeSH
- Publikační typ
- časopisecké články MeSH
Ectropis oblique Prout (Lepidoptera: Geometridae) is one of the main pests that damages the tea crop in Southeast Asia. To understand the molecular mechanisms of its feeding biology, transcriptomes of the alimentary tract (AT) and of the body minus the AT of E. oblique were successfully sequenced and analyzed in this study. A total of 36,950 unigenes from de novo sequences were assembled. After analysis using six annotation databases (e.g., Gene Ontology, Kyoto Encyclopedia of Genes and Genome, and NCBI nr), a series of putative genes were found for this insect species that were related to digestion, detoxification, the immune system, and Bacillus thuringiensis (Bt) receptors. From this series of genes, 21 were randomly selected to verify the relative expression levels of transcripts using quantitative real-time polymerase chain reaction. These results will provide an invaluable genomic resource for future studies on the molecular mechanisms of E. oblique, which will be useful in developing biological control strategies for this pest.
Persistence of Bacillus thuringiensis is an important factor in determining the success of this product as a pest control agent. In this report we present the development of a highly active mosquitocidal formulation with high resistance to UV. LLP29-M19 strain of Bt, selected by repeated exposure to UV was found to be highly resistant to UV. The product was optimized and the methods used were statistically analyzed. Using single-factor experiments it was determined that the optimal concentration of sodium alginate, CaCl2 and hollow glass beads in the formulation were 1.0%, 2.0% and 3.5%, respectively. Plackett-Burman design was used to screen the interaction of the three factors, CaCl2, sodium alginate and hollow glass beads in the sustained-release formulation. The best combined concentration and mutual effects of the three factors were optimized by response surface methodology. The results showed that the most favorable composition was sodium alginate 0.78%, CaCl2 4.52%, hollow glass bead 3.12%, bacterial powder 3.0%, melanin 0.015%, sodium benzoate 0.2%, and mouse feed 0.5%, resulting in the immobilization time of 4.5 h, at which time the corrected sustained-release virulence rose 2391.67 fold, which was 6.07-fold higher than the basic formulation and deviated only 5.0% from the value predicted by RSM.
- MeSH
- algináty farmakologie MeSH
- Bacillus thuringiensis fyziologie MeSH
- bakteriální proteiny farmakologie MeSH
- biologická kontrola škůdců metody MeSH
- biologická ochrana farmakologie MeSH
- Culicidae účinky léků MeSH
- farmaceutická chemie metody MeSH
- kyselina glukuronová farmakologie MeSH
- kyseliny hexuronové farmakologie MeSH
- larva účinky léků MeSH
- léky s prodlouženým účinkem farmakologie MeSH
- moskyti - kontrola metody MeSH
- ultrafialové záření MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The remediation of Pb(II) through biomineralization is rergarded as a promising technique as well as an interesting phenomenon for transforming heavy metals from mobile species into very stable minerals in the environment. Studies are well needed for in-depth understanding the mechanism of Pb(II) immobilized by bacteria. In the present study, we investigated the uptake and biomineralization of Pb(II) using Bacillus cereus 12-2 isolated from lead-zinc mine tailings. The maximum Pb(II) uptake capacity of B. cereus 12-2 was 340 mg/g at pH 3.0. Zeta potential analyses and selective passivation experiments demonstrated that electrostatic attraction was the main force driving the uptake of Pb(II), while the carboxyl, amide and phosphate functional groups of the bacteria provided the binding sites for immobilizing Pb(II). XRD and TEM investigation revealed that the Pb(II) loaded on bacteria could be stepwise transformed into rod-shaped Ca2.5Pb7.5(OH)2(PO4)6 nanocrystal. Combined with protein denaturalization experiments, we proposed that the biomineralization of Pb(II) possibly consisted of two steps: (1) Rapid biosorption of Pb(II) on B. cereus 12-2 through the synergy of electrostatic attraction, ionic exchange and chelating activity of functional groups; (2) enzyme-mediated mineral transformation from amorphous precipitate to rod-shaped crystalline minerals happening gradually inside the bacteria.
Gene expression profiles are important data to reveal the functions of genes putatively involved in crucial biological processes. RNA arbitrarily primed polymerase chain reaction (RAP-PCR) and specifically primed reverse transcription polymerase chain reaction (RT-PCR) were combined to screen differentially expressed genes following development of a commercial Bacillus thuringiensis subsp. kurstaki strain 8010 (serotype 3a3b). Six differentially expressed transcripts (RAP1 to RAP6) were obtained. RAP1 encoded a putative triple helix repeat-containing collagen or an exosporium protein H related to spore pathogenicity. RAP2 was homologous to a ClpX protease and an ATP-dependent protease La (LonB), which likely acted as virulence factors. RAP3 was homologous to a beta subunit of propionyl-CoA carboxylase required for the development of Myxococcus xanthus. RAP4 had homology to a quinone oxidoreductase involved in electron transport and ATP formation. RAP5 showed significant homology to a uridine kinase that mediates phosphorylation of uridine and azauridine. RAP6 shared high sequence identity with 3-methyl-2-oxobutanoate-hydroxymethyltransferase (also known as ketopantoate hydroxymethyltransferase or PanB) involved in the operation of the tricarboxylic acid cycle. The findings described here would help to elucidate the molecular mechanisms underlying the differentiation process of B. thuringiensis and unravel novel pathogenic genes.
- MeSH
- Bacillus thuringiensis klasifikace genetika růst a vývoj izolace a purifikace MeSH
- bakteriální proteiny genetika metabolismus MeSH
- DNA fingerprinting metody MeSH
- polymerázová řetězová reakce s reverzní transkripcí metody MeSH
- regulace genové exprese u bakterií MeSH
- spory bakteriální klasifikace genetika růst a vývoj metabolismus MeSH
- vývojová regulace genové exprese MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
The mechanism of uranium transformation from U(VI) into nano-uramphite by two indigenous Bacillus thuringiensis strains was investigated in the present work. Our data showed that the bacteria isolated from uranium mine possessed highly accumulation ability to U(VI), and the maximum accumulation capacity was around 400 mg U/g biomass (dry weight). X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR) analyzes indicated that the U(VI) was adsorbed on the bacterial surface firstly through coordinating with phosphate, CH2 and amide groups, and then needle-like amorphous uranium compounds were formed. With the extension of time, the extracellular crystalline substances were disappeared, but some particles were appeared in the intracellular region, and these particles were characterized as tetragonal-uramphite. Moreover, the disrupted experiment indicated that the cell-free extracts had better uranium-immobilization ability than cell debris. Our findings provided the understanding of the uranium transformation process from amorphous uranium to crystalline uramphite, which would be useful in the regulation of uranium immobilization process.
- MeSH
- adsorpce MeSH
- amidy chemie MeSH
- Bacillus thuringiensis metabolismus MeSH
- biodegradace MeSH
- biomasa MeSH
- chemické látky znečišťující vodu analýza MeSH
- difrakce rentgenového záření MeSH
- fosfáty chemie MeSH
- hornictví MeSH
- koncentrace vodíkových iontů MeSH
- mikroskopie elektronová rastrovací MeSH
- odpadní voda MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- transmisní elektronová mikroskopie MeSH
- uran chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In this study, we investigated the Cr(VI) uptake mechanism of planktonic cells and biofilms of Bacillus subtilis (B. subtilis) ATCC-6633. Data showed that the effect of planktonic cells on the Cr(VI) uptake was quite different from that of biofilms. Planktonic cells had strong ability of Cr(VI) reduction, while biofilms possessed a great potential of Cr(III) immobilization. For planktonic cells, 100 mg/L Cr(VI) could be completely reduced. Both exopolymeric substances and cytoplasmic extracts contributed to high capacity of Cr(VI) reduction. After the reduction, noticeable Cr(III) precipitates were accumulated on bacterial surfaces, but 37.5% Cr(III) still remained in the supernatant. For biofilms, the biofilm debris became the main active ingredient of the Cr(VI) reduction. However, only 20 mg/L Cr(VI) could be reduced probably because of unavailability of reducing active sites during the biofilm formation. Further studies showed that biofilms had a better Cr(III) immobilization capacity than planktonic cells with 100% Cr(III) immobilized. Moreover, for the first time, we proposed a strategy combining the advantages of both planktonic cells and biofilms, and a successful Cr(VI) removal from typical Cr(VI)-containing plating wastewater was achieved through a 10-L pilot-scale experiment.
