Effect of oxygen on levels of mRNA coding for reaction-centre and light-harvesting polypeptides of <i>Rhodobacter sphaeroides</i>

Hunter, C. Neil; Ashby, Mark K.; Coomber, Shirley A.

doi:10.1042/bj2470489

Cited by 13 publications

(8 citation statements)

References 16 publications

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“…1 can be found at our web site (www.rhodobacter.org) and has been included here as supplementary data, available in the on-line version of this article. As described above there are many published studies that have followed, individually, the expression of a few, but not most of the genes encoding the photosystem in R. sphaeroides (32)(33)(34)(35)(36)(37), or genes encoding enzymes involved in CO 2 fixation (38, 39), nitrogen fixation (40), electron transport (41)(42)(43)(44)(45)(46), taxis (47,48), or assorted transcriptional regulators (16,49,50), etc., using more traditional approaches such as Northern hybridization, lacZ fusions, and even phoA fusions. However, these studies have been by necessity selective, and for the most part the overwhelming majority of these genetic elements comprising the photosynthetic lifestyle have never been investigated under the diverse environmental conditions described here.…”

Section: Effect Of Oxygen and Light On R Sphaeroides Transcriptomementioning

confidence: 99%

Effects of Oxygen and Light Intensity on Transcriptome Expression in Rhodobacter sphaeroides 2.4.1

Roh

Smith

Kaplan

2004

Journal of Biological Chemistry

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The roles of oxygen and light on the regulation of photosynthesis gene expression in Rhodobacter sphaeroides 2.4.1 have been well studied over the past 50 years. More recently, the effects of oxygen and light on gene regulation have been shown to involve the interacting redox chains present in R. sphaeroides under diverse growth conditions, and many of the redox carriers comprising these chains have been well studied. However, the expression patterns of those genes encoding these redox carriers, under aerobic and anaerobic photosynthetic growth, have been less well studied. Here, we provide a transcriptional analysis of many of the genes comprising the photosynthesis lifestyle, including genes corresponding to many of the known regulatory elements controlling the response of this organism to oxygen and light. The observed patterns of gene expression are evaluated and discussed in light of our knowledge of the physiology of R. sphaeroides under aerobic and photosynthetic growth conditions. Finally, this analysis has enabled to us go beyond the traditional patterns of gene expression associated with the photosynthesis lifestyle and to consider, for the first time, the full complement of genes responding to oxygen, and variations in light intensity when growing photosynthetically. The data provided here should be considered as a first step in enabling one to model electron flow in R. sphaeroides 2.4

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Section: Effect Of Oxygen and Light On R Sphaeroides Transcriptomementioning

confidence: 99%

Effects of Oxygen and Light Intensity on Transcriptome Expression in Rhodobacter sphaeroides 2.4.1

Roh

Smith

Kaplan

2004

Journal of Biological Chemistry

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“…No expression of the puc genes that encode proteins of the photosynthetic apparatus is detected in strain APP11 by Northern blot analysis (Fig. 2), even at low oxygen tension when puc mRNA levels in the wild type are high (29). However, a plasmid-borne appA copy (19) [strain 2: APP11(p484-Nco5)] restored functional redox-dependent gene regulation as indicated by pigmentation (Table 1 and Fig.…”

Section: A Hybrid Protein Consisting Of the Pac␣1-bluf Domain From Eumentioning

confidence: 99%

A eukaryotic BLUF domain mediates light-dependent gene expression in the purple bacterium Rhodobacter sphaeroides 2.4.1

Han

Braatsch

Osterloh

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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The flavin-binding BLUF domain functions as a blue-light receptor in eukaryotes and bacteria. In the photoreceptor protein photoactivated adenylyl cyclase (PAC) from the flagellate Euglena gracilis, the BLUF domain is linked to an adenylyl cyclase domain. The PAC protein mediates a photophobic response. In the AppA protein of Rhodobacter sphaeroides, the BLUF domain is linked to a downstream domain without similarity to known proteins. AppA functions as a transcriptional antirepressor, controlling photosynthesis gene expression in the purple bacterium R. sphaeroides in response to light and oxygen. We fused the PAC␣1-BLUF domain from Euglena to the C terminus of AppA. Our results show that the hybrid protein is fully functional in light-dependent gene repression in R. sphaeroides, despite only Ϸ30% identity between the eukaryotic and the bacterial BLUF domains. Furthermore, the bacterial BLUF domain and the C terminus of AppA can transmit the light signal even when expressed as separated domains. This finding implies that the BLUF domain is fully modular and can relay signals to completely different output domains.

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“…In the case of the most studied purple photosynthetic bacterium Rhodobacter sphaeroides, the LH complexes and RCs are only synthesized when the oxygen tension is below a critical value (11,12). Then if cells are grown at high light intensities, the PSU is dominated by LH1/RC core complexes (13,14).…”

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confidence: 99%

Tracking energy transfer between light harvesting complex 2 and 1 in photosynthetic membranes grown under high and low illumination

Lüer

Moulisová

Henry

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Energy transfer (ET) between B850 and B875 molecules in light harvesting complexes LH2 and LH1/RC (reaction center) complexes has been investigated in membranes of Rhodopseudomonas palustris grown under high-and low-light conditions. In these bacteria, illumination intensity during growth strongly affects the type of LH2 complexes synthesized, their optical spectra, and their amount of energetic disorder. We used a specially built femtosecond spectrometer, combining tunable narrowband pump with broadband white-light probe pulses, together with an analytical method based on derivative spectroscopy for disentangling the congested transient absorption spectra of LH1 and LH2 complexes. This procedure allows real-time tracking of the forward (LH2 → LH1) and backward (LH2 ← LH1) ET processes and unambiguous determination of the corresponding rate constants. In low-light grown samples, we measured lower ET rates in both directions with respect to high-light ones, which is explained by reduced spectral overlap between B850 and B875 due to partial redistribution of oscillator strength into a higher energetic exciton transition. We find that the low-light adaptation in R. palustris leads to a reduced elementary backward ET rate, in accordance with the low probability of two simultaneous excitations reaching the same LH1/RC complex under weak illumination. Our study suggests that backward ET is not just an inevitable consequence of vectorial ET with small energetic offsets, but is in fact actively managed by photosynthetic bacteria.bacteriochlorophylls | ultrafast spectroscopy

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Effect of oxygen on levels of mRNA coding for reaction-centre and light-harvesting polypeptides of Rhodobacter sphaeroides

Cited by 13 publications

References 16 publications

Effects of Oxygen and Light Intensity on Transcriptome Expression in Rhodobacter sphaeroides 2.4.1

Effects of Oxygen and Light Intensity on Transcriptome Expression in Rhodobacter sphaeroides 2.4.1

A eukaryotic BLUF domain mediates light-dependent gene expression in the purple bacterium Rhodobacter sphaeroides 2.4.1

Tracking energy transfer between light harvesting complex 2 and 1 in photosynthetic membranes grown under high and low illumination

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