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Chemotaxis of Burkholderia sp. strain SJ98 towards chloronitroaromatic compounds that it can metabolise.

Pandey J, Sharma NK, Khan F, Ghosh A, Oakeshott JG, Jain RK, Pandey G - BMC Microbiol. (2012)

Bottom Line: Moreover, the chemotaxis was induced by growth in the presence of the metabolisable CNAC.It was also competitively inhibited by the presence of nitroaromatic compounds (NACs) that it could metabolise but not by succinate or aspartate.Its chemotactic responses towards these compounds are related to its previously demonstrated chemotaxis towards NACs that it can metabolise, but it is independently inducible from its chemotaxis towards succinate or aspartate.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India.

ABSTRACT

Background: Burkholderia sp. strain SJ98 is known for its chemotaxis towards nitroaromatic compounds (NACs) that are either utilized as sole sources of carbon and energy or co-metabolized in the presence of alternative carbon sources. Here we test for the chemotaxis of this strain towards six chloro-nitroaromatic compounds (CNACs), namely 2-chloro-4-nitrophenol (2C4NP), 2-chloro-3-nitrophenol (2C3NP), 4-chloro-2-nitrophenol (4C2NP), 2-chloro-4-nitrobenzoate (2C4NB), 4-chloro-2-nitrobenzoate (4C2NB) and 5-chloro-2-nitrobenzoate (5C2NB), and examine its relationship to the degradation of such compounds.

Results: Strain SJ98 could mineralize 2C4NP, 4C2NB and 5C2NB, and co-metabolically transform 2C3NP and 2C4NB in the presence of an alternative carbon source, but was unable to transform 4C2NP under these conditions. Positive chemotaxis was only observed towards the five metabolically transformed CNACs. Moreover, the chemotaxis was induced by growth in the presence of the metabolisable CNAC. It was also competitively inhibited by the presence of nitroaromatic compounds (NACs) that it could metabolise but not by succinate or aspartate.

Conclusions: Burkholderia sp. strain SJ98 exhibits metabolic transformation of, and inducible chemotaxis towards CNACs. Its chemotactic responses towards these compounds are related to its previously demonstrated chemotaxis towards NACs that it can metabolise, but it is independently inducible from its chemotaxis towards succinate or aspartate.

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Chemotaxis of Burkholderia sp. strain SJ98 towards 2C4NP, 4C2NB and succinate in the presence of other chemicals as competitive attractant. Cells of strain SJ98 grown on 2C4NP, 4C2NB or succinate were subjected to capillary assays in the presence of a second capillary filled with a test chemical (shown in the figure). Values are presented as arithmetic means and error bars indicate standard deviations based on three independent replicates.
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Figure 4: Chemotaxis of Burkholderia sp. strain SJ98 towards 2C4NP, 4C2NB and succinate in the presence of other chemicals as competitive attractant. Cells of strain SJ98 grown on 2C4NP, 4C2NB or succinate were subjected to capillary assays in the presence of a second capillary filled with a test chemical (shown in the figure). Values are presented as arithmetic means and error bars indicate standard deviations based on three independent replicates.

Mentions: Competitive capillary chemotaxis assays were performed to test how the chemotaxis of strain SJ98 towards CNACs is affected by the presence of another chemoattractant. In previous studies, strain SJ98 was reported to be chemotactic towards a number of NACs and simple carbon sources e.g. succinate, aspartate etc. [20-22]. We therefore used capillaries containing optimal response concentrations of different NACs, aspartate or succinate as competitive chemoattractants. Cells of strain SJ98 grown on 2C4NP or 4C2NB as the sole source of carbon and therefore induced for chemotaxis towards CNACs were used for the assays. Results from these experiments showed ~40-55% lower CI values in the presence of a NAC known to be a chemoattractant (PNP, 4-NC or ONB) (Figure 4). However no decrease in chemotactic response was observed in the presence of either aspartate or succinate. Significantly, the presence of 4C2NP or o- nitrophenol (ONP) (a CNAC and a NAC that are not transformed by strain SJ98; see above and [20]) did not elicit an inhibitory effect (Figure 4).


Chemotaxis of Burkholderia sp. strain SJ98 towards chloronitroaromatic compounds that it can metabolise.

Pandey J, Sharma NK, Khan F, Ghosh A, Oakeshott JG, Jain RK, Pandey G - BMC Microbiol. (2012)

Chemotaxis of Burkholderia sp. strain SJ98 towards 2C4NP, 4C2NB and succinate in the presence of other chemicals as competitive attractant. Cells of strain SJ98 grown on 2C4NP, 4C2NB or succinate were subjected to capillary assays in the presence of a second capillary filled with a test chemical (shown in the figure). Values are presented as arithmetic means and error bars indicate standard deviations based on three independent replicates.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3293717&req=5

Figure 4: Chemotaxis of Burkholderia sp. strain SJ98 towards 2C4NP, 4C2NB and succinate in the presence of other chemicals as competitive attractant. Cells of strain SJ98 grown on 2C4NP, 4C2NB or succinate were subjected to capillary assays in the presence of a second capillary filled with a test chemical (shown in the figure). Values are presented as arithmetic means and error bars indicate standard deviations based on three independent replicates.
Mentions: Competitive capillary chemotaxis assays were performed to test how the chemotaxis of strain SJ98 towards CNACs is affected by the presence of another chemoattractant. In previous studies, strain SJ98 was reported to be chemotactic towards a number of NACs and simple carbon sources e.g. succinate, aspartate etc. [20-22]. We therefore used capillaries containing optimal response concentrations of different NACs, aspartate or succinate as competitive chemoattractants. Cells of strain SJ98 grown on 2C4NP or 4C2NB as the sole source of carbon and therefore induced for chemotaxis towards CNACs were used for the assays. Results from these experiments showed ~40-55% lower CI values in the presence of a NAC known to be a chemoattractant (PNP, 4-NC or ONB) (Figure 4). However no decrease in chemotactic response was observed in the presence of either aspartate or succinate. Significantly, the presence of 4C2NP or o- nitrophenol (ONP) (a CNAC and a NAC that are not transformed by strain SJ98; see above and [20]) did not elicit an inhibitory effect (Figure 4).

Bottom Line: Moreover, the chemotaxis was induced by growth in the presence of the metabolisable CNAC.It was also competitively inhibited by the presence of nitroaromatic compounds (NACs) that it could metabolise but not by succinate or aspartate.Its chemotactic responses towards these compounds are related to its previously demonstrated chemotaxis towards NACs that it can metabolise, but it is independently inducible from its chemotaxis towards succinate or aspartate.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India.

ABSTRACT

Background: Burkholderia sp. strain SJ98 is known for its chemotaxis towards nitroaromatic compounds (NACs) that are either utilized as sole sources of carbon and energy or co-metabolized in the presence of alternative carbon sources. Here we test for the chemotaxis of this strain towards six chloro-nitroaromatic compounds (CNACs), namely 2-chloro-4-nitrophenol (2C4NP), 2-chloro-3-nitrophenol (2C3NP), 4-chloro-2-nitrophenol (4C2NP), 2-chloro-4-nitrobenzoate (2C4NB), 4-chloro-2-nitrobenzoate (4C2NB) and 5-chloro-2-nitrobenzoate (5C2NB), and examine its relationship to the degradation of such compounds.

Results: Strain SJ98 could mineralize 2C4NP, 4C2NB and 5C2NB, and co-metabolically transform 2C3NP and 2C4NB in the presence of an alternative carbon source, but was unable to transform 4C2NP under these conditions. Positive chemotaxis was only observed towards the five metabolically transformed CNACs. Moreover, the chemotaxis was induced by growth in the presence of the metabolisable CNAC. It was also competitively inhibited by the presence of nitroaromatic compounds (NACs) that it could metabolise but not by succinate or aspartate.

Conclusions: Burkholderia sp. strain SJ98 exhibits metabolic transformation of, and inducible chemotaxis towards CNACs. Its chemotactic responses towards these compounds are related to its previously demonstrated chemotaxis towards NACs that it can metabolise, but it is independently inducible from its chemotaxis towards succinate or aspartate.

Show MeSH
Related in: MedlinePlus