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Nitrogen starvation-induced transcriptome alterations and influence of transcription regulator mutants in Mycobacterium smegmatis.

Jeßberger N, Lu Y, Amon J, Titgemeyer F, Sonnewald S, Reid S, Burkovski A - BMC Res Notes (2013)

Bottom Line: This includes changes in the transcription of several hundred genes encoding e.g. transport proteins, proteins involved in nitrogen metabolism and regulation, energy generation and protein turnover.The specific nitrogen-related changes at the transcriptional level depend mainly on the presence of GlnR, while the AmtR protein controls only a small number of genes.M. smegmatis is able to metabolize a number of different nitrogen sources and nitrogen control in M. smegmatis is similar to control mechanisms characterized in streptomycetes, while the master regulator of nitrogen control in corynebacteria, AmtR, is plays a minor role in this regulatory network.

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Affiliation: Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany. aburkov@biologie.uni-erlangen.de.

ABSTRACT

Background: As other bacteria, Mycobacterium smegmatis needs adaption mechanisms to cope with changing nitrogen sources and to survive situations of nitrogen starvation. In the study presented here, transcriptome analyses were used to characterize the response of the bacterium to nitrogen starvation and to elucidate the role of specific transcriptional regulators.

Results: In response to nitrogen deprivation, a general starvation response is induced in M. smegmatis. This includes changes in the transcription of several hundred genes encoding e.g. transport proteins, proteins involved in nitrogen metabolism and regulation, energy generation and protein turnover. The specific nitrogen-related changes at the transcriptional level depend mainly on the presence of GlnR, while the AmtR protein controls only a small number of genes.

Conclusions: M. smegmatis is able to metabolize a number of different nitrogen sources and nitrogen control in M. smegmatis is similar to control mechanisms characterized in streptomycetes, while the master regulator of nitrogen control in corynebacteria, AmtR, is plays a minor role in this regulatory network.

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Growth of M. smegmatis in various nitrogen sources. Wild-type SMR5 and glnR deletion strain MH1 were grown in the presence of the indicated substances (10 mM final concentration) as sole nitrogen source. Standard 7H9 medium was used as positive control; 7H9 lacking any nitrogen source as negative control (7H9-N). (A) Putative nitrogen sources deduced from microarray results, (B) putative nitrogen sources used by closely related species.
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Figure 6: Growth of M. smegmatis in various nitrogen sources. Wild-type SMR5 and glnR deletion strain MH1 were grown in the presence of the indicated substances (10 mM final concentration) as sole nitrogen source. Standard 7H9 medium was used as positive control; 7H9 lacking any nitrogen source as negative control (7H9-N). (A) Putative nitrogen sources deduced from microarray results, (B) putative nitrogen sources used by closely related species.

Mentions: Growth experiments were carried out using the various substances tested as sole nitrogen source and comparing wild-type and ΔglnR strain MH1 (Figure 6). 7H9 medium was used as positive control and nitrogen-free 7H9 (7H9-N) as negative control. Standard 7H9 medium contains ammonium sulphate, ferric ammonium citrate and glutamic acid as nitrogen sources. When ammonium sulphate and ferric ammonium citrate were tested alone, a reduced growth rate and final OD600 was observed, independently from the presence or absence of GlnR, reflecting that ammonium (NH4+) is membrane-permeable in its unprotonated form ammonia (NH3) and that under the growth conditions tested, ammonium was not limiting.


Nitrogen starvation-induced transcriptome alterations and influence of transcription regulator mutants in Mycobacterium smegmatis.

Jeßberger N, Lu Y, Amon J, Titgemeyer F, Sonnewald S, Reid S, Burkovski A - BMC Res Notes (2013)

Growth of M. smegmatis in various nitrogen sources. Wild-type SMR5 and glnR deletion strain MH1 were grown in the presence of the indicated substances (10 mM final concentration) as sole nitrogen source. Standard 7H9 medium was used as positive control; 7H9 lacking any nitrogen source as negative control (7H9-N). (A) Putative nitrogen sources deduced from microarray results, (B) putative nitrogen sources used by closely related species.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4222082&req=5

Figure 6: Growth of M. smegmatis in various nitrogen sources. Wild-type SMR5 and glnR deletion strain MH1 were grown in the presence of the indicated substances (10 mM final concentration) as sole nitrogen source. Standard 7H9 medium was used as positive control; 7H9 lacking any nitrogen source as negative control (7H9-N). (A) Putative nitrogen sources deduced from microarray results, (B) putative nitrogen sources used by closely related species.
Mentions: Growth experiments were carried out using the various substances tested as sole nitrogen source and comparing wild-type and ΔglnR strain MH1 (Figure 6). 7H9 medium was used as positive control and nitrogen-free 7H9 (7H9-N) as negative control. Standard 7H9 medium contains ammonium sulphate, ferric ammonium citrate and glutamic acid as nitrogen sources. When ammonium sulphate and ferric ammonium citrate were tested alone, a reduced growth rate and final OD600 was observed, independently from the presence or absence of GlnR, reflecting that ammonium (NH4+) is membrane-permeable in its unprotonated form ammonia (NH3) and that under the growth conditions tested, ammonium was not limiting.

Bottom Line: This includes changes in the transcription of several hundred genes encoding e.g. transport proteins, proteins involved in nitrogen metabolism and regulation, energy generation and protein turnover.The specific nitrogen-related changes at the transcriptional level depend mainly on the presence of GlnR, while the AmtR protein controls only a small number of genes.M. smegmatis is able to metabolize a number of different nitrogen sources and nitrogen control in M. smegmatis is similar to control mechanisms characterized in streptomycetes, while the master regulator of nitrogen control in corynebacteria, AmtR, is plays a minor role in this regulatory network.

View Article: PubMed Central - HTML - PubMed

Affiliation: Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany. aburkov@biologie.uni-erlangen.de.

ABSTRACT

Background: As other bacteria, Mycobacterium smegmatis needs adaption mechanisms to cope with changing nitrogen sources and to survive situations of nitrogen starvation. In the study presented here, transcriptome analyses were used to characterize the response of the bacterium to nitrogen starvation and to elucidate the role of specific transcriptional regulators.

Results: In response to nitrogen deprivation, a general starvation response is induced in M. smegmatis. This includes changes in the transcription of several hundred genes encoding e.g. transport proteins, proteins involved in nitrogen metabolism and regulation, energy generation and protein turnover. The specific nitrogen-related changes at the transcriptional level depend mainly on the presence of GlnR, while the AmtR protein controls only a small number of genes.

Conclusions: M. smegmatis is able to metabolize a number of different nitrogen sources and nitrogen control in M. smegmatis is similar to control mechanisms characterized in streptomycetes, while the master regulator of nitrogen control in corynebacteria, AmtR, is plays a minor role in this regulatory network.

Show MeSH
Related in: MedlinePlus