Accumulation of ppGpp and pppGpp during nitrogen deprivation of the cyanophyte <i>Anabaena cylindrica</i>

Akinyanju, J. A.; Smith, Richard J.

doi:10.1016/0014-5793(79)80489-5

Cited by 30 publications

(23 citation statements)

References 11 publications

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“…Thus, we conclude that the interruption of Rel ana results in a very low level of ppGpp synthesis in the mutant. It was reported a long time ago that ppGpp levels increase at the early stage of heterocyst differentiation (59,60). Our data further indicate that this ppGpp synthesis activity is required for heterocyst development.…”

Section: Discussionsupporting

confidence: 84%

ppGpp Metabolism Is Involved in Heterocyst Development in the Cyanobacterium Anabaena sp. Strain PCC 7120

et al. 2013

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Here we show that all1549 (here designated rel ana ) in Anabaena, homologous to relA/spoT, is upregulated in response to nitrogen deprivation and predominantly localized in vegetative cells. The disruption of rel ana strongly affects the synthesis of ppGpp, and the resulting mutant, all1549⍀sp/sm, fails to form heterocysts and to grow in the absence of a combined-nitrogen source. This phenotype can be complemented by a wild-type copy of rel ana . Although the upregulation of hetR is affected in the mutant, ectopic overexpression of hetR cannot rescue the phenotype. However, we found that the mutant rapidly loses its viability, within a time window of 3 to 6 h, following the deprivation of combined nitrogen. We propose that ppGpp plays a major role in rebalancing the metabolic activities of the cells in the absence of the nitrogen source supply and that this regulation is necessary for filament survival and consequently for the success of heterocyst differentiation.

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Section: Discussionsupporting

confidence: 84%

ppGpp Metabolism Is Involved in Heterocyst Development in the Cyanobacterium Anabaena sp. Strain PCC 7120

et al. 2013

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“…However, there are conflicting results for the correlation between nitrogen starvation and ppGpp accumulation (1,2,11,17,25) and the effect of light (hence, energy) deprivation, which does not seem to be comparable with the nutritional step-down of heterotrophic bacteria (3,17,25). In studies dealing with the light-dependent regulation of gene expression in Synechococcus sp., an obligate autotrophic cyanobacterium, the pleiotropic nature of regulatory responses has been emphasized (9,23).…”

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Effects of light deprivation on RNA synthesis, accumulation of guanosine 3'(2')-diphosphate 5'-diphosphate, and protein synthesis in heat-shocked Synechococcus sp. strain PCC 6301, a cyanobacterium

et al. 1987

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The rate of total RNA synthesis, the extent of guanosine 3'(2')-diphosphate 5 '-diphosphate (ppGpp) accumulation, and the pattern of protein synthesis were studied in light-deprived and heat-shocked Synechococcus sp. strain PCC 6301 cells. There was an inverse correlation between the rate of total RNA synthesis and the pool size of ppGpp, except immediately after a temperature shift up, when a parallel increase in the rate of RNA synthesis and accumulation of ppGpp was observed. The inverse correlation between RNA synthesis and ppGpp accumulation was more pronounced when cells were grown in the dark. Heat shock treatment (47°C) had an unexpected effect on ppGpp accumulation; there was a fairly stable level of ppGpp under heat shock conditions, which coincided with a stable steady-state rate of RNA synthesis even in the dark. We found that the pattern of dark-specific proteins was altered in response to heat shock. The transient synthesis of several dark-specific proteins was abolished by an elevated temperature (47C) in the dark; moreover, the main heat shock proteins were synthesized even in the dark. This phenomenon might be of aid in the study of cyanobacterial gene expression.

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“…shifts (21,26), and nitrogen deprivation (1) are all thought to be mediated, in part, by the effector properties of ppGpp. However, the exact mechanisms by which ppGpp exerts its regulatory effects are, in most cases, unknown.…”

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Stringency in the absence of ppGpp accumulation in Rhodobacter sphaeroides

Acosta¹,

Lueking²

1987

J Bacteriol

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(7) have proposed that the coincident restrictions in biosynthetic activity observed following such a light transition (7,11,16,23) are mediated by ppGpp. This proposal is especially compelling with regard to cellular phospholipid synthesis, because both the percent inhibition of the rate of phospholipid synthesis and the extent of accumulation of cellular ppGpp were found to be directly related to the magnitude of the light transition. However, a direct involvement of ppGpp in the control of phospholipid synthesis or other cellular biosynthetic activities was not established, and the mechanism responsible for the light-mediated formation of ppGpp was not identified.To evaluate the potential effector role of ppGpp in the coordination of metabolic processes in R. sphaeroides, we found it of interest to determine whether R. sphaeroides possessed a typical ribosome-dependent, Rel+ mechanism for the production of ppGpp and, if present, whether this mechanism was involved in the light-mediated formation of ppGpp. Cells of R. sphaeroides M29-5 (Leu-Met-) were grown in t succinic acid minimal medium as described by Lueking et al. (24) and were deprived of leucine by being washed and suspended in medium lacking this amino acid. Cells used for nucleotide measurements were adapted and grown in the low.phosphate minimal medium described by Campbell and Lueking (8). Phototrophic growth was conducted under an atmosphere of 95% N2-5% CO2 at 31°C and with saturrating illumination (5,380 Ix). Chemotrophic growth was conducted aerobically in the dark with constant sparging

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Accumulation of ppGpp and pppGpp during nitrogen deprivation of the cyanophyte Anabaena cylindrica

Cited by 30 publications

References 11 publications

ppGpp Metabolism Is Involved in Heterocyst Development in the Cyanobacterium Anabaena sp. Strain PCC 7120

ppGpp Metabolism Is Involved in Heterocyst Development in the Cyanobacterium Anabaena sp. Strain PCC 7120

Effects of light deprivation on RNA synthesis, accumulation of guanosine 3'(2')-diphosphate 5'-diphosphate, and protein synthesis in heat-shocked Synechococcus sp. strain PCC 6301, a cyanobacterium

Stringency in the absence of ppGpp accumulation in Rhodobacter sphaeroides

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