Limits...
Proteomics Analysis of the Effects of Cyanate on Chromobacterium violaceum Metabolism.

Baraúna RA, Ciprandi A, Santos AV, Carepo MS, Gonçalves EC, Schneider MP, Silva A - Genes (Basel) (2011)

Bottom Line: The proteome of cells grown with and without cyanate was compared on 2-D gels.Fourteen spots were identified, corresponding to 13 different proteins.We conclude that cyanate promotes expression of enzymes that combat oxidative stress and represses enzymes of the citric acid cycle, strongly affecting the energetic metabolism of the cell.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Polimorfismo de DNA, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará 66075-110, Brasil. rabarauna@ufpa.br.

ABSTRACT
Chromobacterium violaceum is a gram-negative betaproteobacterium that has been isolated from various Brazilian ecosystems. Its genome contains the cyn operon, which gives it the ability to metabolize highly toxic cyanate into ammonium and carbon dioxide. We used a proteomics approach to investigate the effects of cyanate on the metabolism of this bacterium. The proteome of cells grown with and without cyanate was compared on 2-D gels. Differential spots were digested and identified by mass spectrometry. The bacterium was able to grow at concentrations of up to 1 mM cyanate. Eighteen spots were differentially expressed in the presence of cyanate, of which 16 were downregulated and only two were upregulated. An additional 12 spots were detected only in extracts of cells unexposed to cyanate, and one was expressed only by the exposed cells. Fourteen spots were identified, corresponding to 13 different proteins. We conclude that cyanate promotes expression of enzymes that combat oxidative stress and represses enzymes of the citric acid cycle, strongly affecting the energetic metabolism of the cell. Other proteins that were under-expressed in bacteria exposed to cyanate are involved in amino-acid metabolism or are hypothetical proteins, demonstrating that cyanate also affects expression of genes that are not part of the cyn operon.

No MeSH data available.


Related in: MedlinePlus

Resistance of Chromobacterium violaceum to cyanate (CNO−). The resistance assays were conducted at five concentrations of cyanate (1, 5, 10, 20 and 50 mM), using two groups of cells, not induced and induced with 0.1 mM cyanate. The error bars indicate the standard deviations for the mean values derived from the analyses in triplicate. Data on the growth of the two groups was compared using ANOVA, with a p < 0.05 significance level.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3927592&req=5

f1-genes-02-00736: Resistance of Chromobacterium violaceum to cyanate (CNO−). The resistance assays were conducted at five concentrations of cyanate (1, 5, 10, 20 and 50 mM), using two groups of cells, not induced and induced with 0.1 mM cyanate. The error bars indicate the standard deviations for the mean values derived from the analyses in triplicate. Data on the growth of the two groups was compared using ANOVA, with a p < 0.05 significance level.

Mentions: Chromobacterium violaceum was grown in various concentrations of cyanate in order to evaluate its resistance to this compound. The bacteria grow well at concentrations of cyanate of up to 1 mM (Figure 1). At 5 mM, growth was 67% of that observed in the control group. Thus, C. violaceum was able to grow in concentrations of cyanate normally founded in aquatic environments associated with mine tailings [19]. Above 10 mM, however, C. violaceum was unable to metabolize the cyanate effectively, and growth was inhibited considerably. At 50 mM, the bacterial growth was close to zero. Resistance tests were conducted on two groups of bacteria, one of which was initially cultured in medium with a low concentration of cyanate (0.1 mM) prior to exposure to higher experimental concentrations (white bars in Figure 1). This procedure was used to test whether exposure to small doses of this toxic compound would increase the resistance of the bacteria. However, no significant difference in resistance was found between the groups (Figure 1). This result indicates that probably the cyn operon is not responsible for the C. violaceum resistance to cyanate. The ability of Escherichia coli and bacteria of the genus Pseudomonas to grow in the presence of cyanate has been described but the cyn operon is not always involved in the resistance [13,20,21]. In Pseudomonas pseudoalcaligenes the tolerance to cyanate of a cynS mutant was similar to the wild type showing that the cyn operon is not involved in the resistance mechanism [13].


Proteomics Analysis of the Effects of Cyanate on Chromobacterium violaceum Metabolism.

Baraúna RA, Ciprandi A, Santos AV, Carepo MS, Gonçalves EC, Schneider MP, Silva A - Genes (Basel) (2011)

Resistance of Chromobacterium violaceum to cyanate (CNO−). The resistance assays were conducted at five concentrations of cyanate (1, 5, 10, 20 and 50 mM), using two groups of cells, not induced and induced with 0.1 mM cyanate. The error bars indicate the standard deviations for the mean values derived from the analyses in triplicate. Data on the growth of the two groups was compared using ANOVA, with a p < 0.05 significance level.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3927592&req=5

f1-genes-02-00736: Resistance of Chromobacterium violaceum to cyanate (CNO−). The resistance assays were conducted at five concentrations of cyanate (1, 5, 10, 20 and 50 mM), using two groups of cells, not induced and induced with 0.1 mM cyanate. The error bars indicate the standard deviations for the mean values derived from the analyses in triplicate. Data on the growth of the two groups was compared using ANOVA, with a p < 0.05 significance level.
Mentions: Chromobacterium violaceum was grown in various concentrations of cyanate in order to evaluate its resistance to this compound. The bacteria grow well at concentrations of cyanate of up to 1 mM (Figure 1). At 5 mM, growth was 67% of that observed in the control group. Thus, C. violaceum was able to grow in concentrations of cyanate normally founded in aquatic environments associated with mine tailings [19]. Above 10 mM, however, C. violaceum was unable to metabolize the cyanate effectively, and growth was inhibited considerably. At 50 mM, the bacterial growth was close to zero. Resistance tests were conducted on two groups of bacteria, one of which was initially cultured in medium with a low concentration of cyanate (0.1 mM) prior to exposure to higher experimental concentrations (white bars in Figure 1). This procedure was used to test whether exposure to small doses of this toxic compound would increase the resistance of the bacteria. However, no significant difference in resistance was found between the groups (Figure 1). This result indicates that probably the cyn operon is not responsible for the C. violaceum resistance to cyanate. The ability of Escherichia coli and bacteria of the genus Pseudomonas to grow in the presence of cyanate has been described but the cyn operon is not always involved in the resistance [13,20,21]. In Pseudomonas pseudoalcaligenes the tolerance to cyanate of a cynS mutant was similar to the wild type showing that the cyn operon is not involved in the resistance mechanism [13].

Bottom Line: The proteome of cells grown with and without cyanate was compared on 2-D gels.Fourteen spots were identified, corresponding to 13 different proteins.We conclude that cyanate promotes expression of enzymes that combat oxidative stress and represses enzymes of the citric acid cycle, strongly affecting the energetic metabolism of the cell.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Polimorfismo de DNA, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará 66075-110, Brasil. rabarauna@ufpa.br.

ABSTRACT
Chromobacterium violaceum is a gram-negative betaproteobacterium that has been isolated from various Brazilian ecosystems. Its genome contains the cyn operon, which gives it the ability to metabolize highly toxic cyanate into ammonium and carbon dioxide. We used a proteomics approach to investigate the effects of cyanate on the metabolism of this bacterium. The proteome of cells grown with and without cyanate was compared on 2-D gels. Differential spots were digested and identified by mass spectrometry. The bacterium was able to grow at concentrations of up to 1 mM cyanate. Eighteen spots were differentially expressed in the presence of cyanate, of which 16 were downregulated and only two were upregulated. An additional 12 spots were detected only in extracts of cells unexposed to cyanate, and one was expressed only by the exposed cells. Fourteen spots were identified, corresponding to 13 different proteins. We conclude that cyanate promotes expression of enzymes that combat oxidative stress and represses enzymes of the citric acid cycle, strongly affecting the energetic metabolism of the cell. Other proteins that were under-expressed in bacteria exposed to cyanate are involved in amino-acid metabolism or are hypothetical proteins, demonstrating that cyanate also affects expression of genes that are not part of the cyn operon.

No MeSH data available.


Related in: MedlinePlus