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PCR-based DNA test for detection of emetic Bacillus cereus strains producing cereulide

100%

Oltuszak-Walczak E., Walczak P.

Polish Journal of Food and Nutrition Sciences

2007

tom 57

nr 3[A]

Two PCR-based methods for identification of emetic toxin producing Bacillus cereus strains were developed. The first set of primers cesBF and cesBR allowed for the amplification of cesBI 838 bp long fragment of cereulide biosynthesis operon for cereulide producing strains, or 421 bp long fragment of nonribosomal peptide synthetase (nrps) for emetic toxin non producing strains. Detection of both genes cesBI and nrps was possible in one PCR reaction. Among 24 strains of Cereus group tested, only one named 19W-cesB contained cesBI gene fragment. Bacillus cereus isolate 19W-cesB did not contain of any other genes of nonribosomal peptide synthetases responsible for the synthesis of other low molecular weight peptide toxins. The shdR and shdF second primer set allowed for specific amplification of the other 690 bp long fragment of cesBII gene. Only strain 19W-cesB allowed for the PCR synthesis of appropriate amplicon from all tested strains. Proposed methods may be fast and reliable techniques for detection of Bacillus cereus strains producing cereulide.

Cereulide and valinomycin, two important natural dodecadepsipeptides with ionophoretic activities

84%

Kroten M. A., Bartoszewicz M., Swiecicka I.

Polish Journal of Microbiology

2010

tom 59

nr 1

3-10

Cereulide produced by Bacillus cereus sensu stricto and valinomycin synthesized mainly by Streptomyces spp. are natural dodecadepsipeptide ionophores that act as potassium transporters. Moreover, they comprise three repetitions of similar tetrapeptide motifs synthesized by non-ribosomal peptide synthesis complexes. Resemblances in their structure find their reflections in the same way of action. The toxicity of valinomycin and cereulide is an effect of the disturbance of ionic equilibrium and transmembrane potential that may influence the whole organism and then cause fatal consequences. The vim and ces operons encoding valinomycin and cereulide are both composed of two large, similar synthetase genes, one thioestrase gene and four other ORFs with unknown activities. In spite of the characterization of valinomycin and cereulide, genetic determinants encoding their biosynthesis have not yet been clarified.

Differentiated Paju cells have increased resistance to toxic effects of potassium ionophores

84%

Teplova V., Jaaskelainen E., Salkinoja-Salonen M., Saris N. E. L., Serlachius M., Li F. Y., Andersson L. C.

Acta Biochimica Polonica

2004

tom 51

nr 2

In this study we have investigated the impact of differentiation of neuronal cells on their sensitivity to microbial toxins. We used the human neural crest-derived tumor cell line Paju, which can be induced to differentiation in vitro by treatment with phorbol 12-myristate 13-acetate. Addition of the highly toxic potassium ionophores cereulide (4.5 and 9.0 ng/ml) or valinomycin (20 ng/ml), to cultures of undifferentiated Paju cells caused collapse of the mitochondrial membrane potential — measured with the fluorescent probe 5,5',6,6'-tetrachloro-1,1',3,3'-tetrabenzimidazole carbo- cyanine iodide (JC-1) followed by detachment of the cells and their apoptotic death. After induced differentiation of the Paju cells, their mitochondria retained the membrane potential upon exposure to the toxins and the cells displayed increased resistance to apoptosis as compared with undifferentiated cells. This effect may be caused by an elevated expression of the anti-apoptotic protein Bcl-2 and of the neuroprotective factor, stanniocalcin, in differentiated cells.

Ograniczanie wyników

1 Acta Biochimica Polonica

1 Polish Journal of Food and Nutrition Sciences

1 Polish Journal of Microbiology

1 Andersson L. C.

1 Bartoszewicz M.

1 Jaaskelainen E.

1 Kroten M. A.

1 Li F. Y.

1 Oltuszak-Walczak E.

1 Salkinoja-Salonen M.

1 Saris N. E. L.

1 Serlachius M.

1 Swiecicka I.

1 Teplova V.

1 Walczak P.

1 2010

1 2007

1 2004

Wyniki wyszukiwania

PCR-based DNA test for detection of emetic Bacillus cereus strains producing cereulide

Cereulide and valinomycin, two important natural dodecadepsipeptides with ionophoretic activities

Differentiated Paju cells have increased resistance to toxic effects of potassium ionophores