The Photosynthetic Apparatus of Chlorophyll b- and d-Containing Oxyphotobacteria

Partensky, Frédéric; Garczarek, Laurence

doi:10.1007/978-94-007-1038-2_3

Cited by 43 publications

(40 citation statements)

References 167 publications

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“…While initial observations explained its ecological success mainly on the basis of photosynthetic adaptations to efficiently colonize most of the photic zone of the oceans (3,14,48,58,60,61), it is now becoming clear that other major metabolic changes contribute significantly to such success, as evidenced in the present review on the nitrogen assimilation pathways in Prochlorococcus. Further work is required to understand the importance of these changes for Prochlorococcus fitness in oligotrophic regions of the oceans and their specific relationship with the niche differentiation described for the different Prochlorococcus ecotypes (49,79,80 …”

Section: Discussionmentioning

confidence: 73%

Streamlined Regulation and Gene Loss as Adaptive Mechanisms in Prochlorococcus for Optimized Nitrogen Utilization in Oligotrophic Environments

García-Fernández

Marsac

Dı́ez

2004

Microbiol Mol Biol Rev

111

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Prochlorococcus is one of the dominant cyanobacteria and a key primary producer in oligotrophic intertropical oceans. Here we present an overview of the pathways of nitrogen assimilation in Prochlorococcus, which have been significantly modified in these microorganisms for adaptation to the natural limitations of their habitats, leading to the appearance of different ecotypes lacking key enzymes, such as nitrate reductase, nitrite reductase, or urease, and to the simplification of the metabolic regulation systems. The only nitrogen source utilizable by all studied isolates is ammonia, which is incorporated into glutamate by glutamine synthetase. However, this enzyme shows unusual regulatory features, although its structural and kinetic features are unchanged. Similarly, urease activities remain fairly constant under different conditions. The signal transduction protein PII is apparently not phosphorylated in Prochlorococcus, despite its conserved amino acid sequence. The genes amt1 and ntcA (coding for an ammonium transporter and a global nitrogen regulator, respectively) show noncorrelated expression in Prochlorococcus under nitrogen stress; furthermore, high rates of organic nitrogen uptake have been observed. All of these unusual features could provide a physiological basis for the predominance of Prochlorococcus over Synechococcus in oligotrophic oceans

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Section: Discussionmentioning

confidence: 73%

Streamlined Regulation and Gene Loss as Adaptive Mechanisms in Prochlorococcus for Optimized Nitrogen Utilization in Oligotrophic Environments

García-Fernández

Marsac

Dı́ez

2004

Microbiol Mol Biol Rev

111

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“…Prochlorococcus is an atypical cyanobacterium, since its main antenna complexes comprise thylakoid membrane proteins binding unique divinyl derivatives of Chl a and b (so-called Chl a 2 and b 2 ) (98,142,218,270). Though this membrane-internal antenna has replaced ancestral phycobilisomes, resulting in the complete loss of phycocyanin and allophycocyanin genes, some phycoerythrin genes are still present in Prochlorococcus genomes.…”

Section: Light Harvestingmentioning

confidence: 99%

“…In a process which is somewhat akin to a simple form of chromatic adaptation, cells can increase their Chl b 2 -to-Chl b 1 ratio at lower light levels (and vice versa). Therefore, they must also possess a divinyl reductase with a high substrate specificity for Chl b 2 , since these strains do not contain any Chl a 1 (191,218,220). Thus, besides the dvr gene product, reduction of divinyl-Chl forms likely involves one of several yet-to-be-identified enzymes, which might be specific to marine picocyanobacteria.…”

Section: Pigment Biosynthesismentioning

confidence: 99%

“…The enzyme responsible for the conversion of Chl a 2 to Chl b 2 in Prochlorococcus provides a good example of such a specific protein. Indeed, this process involves a very distantly related homolog of the cao gene, encoding chlorophyllide a oxygenase (also called Chl b synthase) in higher plants, green algae, and the green oxyphotobacteria Prochloron and Prochlorothrix (115,218,284). The role of the so-called PcCAO gene of Prochlorococcus marinus MED4 has recently been confirmed by introducing it into Synechocystis sp.…”

Section: Pigment Biosynthesismentioning

confidence: 99%

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Ecological Genomics of Marine Picocyanobacteria

Scanlan

Ostrowski

Mazard

et al. 2009

Microbiol Mol Biol Rev

646

824

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SUMMARY Marine picocyanobacteria of the genera Prochlorococcus and Synechococcus numerically dominate the picophytoplankton of the world ocean, making a key contribution to global primary production. Prochlorococcus was isolated around 20 years ago and is probably the most abundant photosynthetic organism on Earth. The genus comprises specific ecotypes which are phylogenetically distinct and differ markedly in their photophysiology, allowing growth over a broad range of light and nutrient conditions within the 45°N to 40°S latitudinal belt that they occupy. Synechococcus and Prochlorococcus are closely related, together forming a discrete picophytoplankton clade, but are distinguishable by their possession of dissimilar light-harvesting apparatuses and differences in cell size and elemental composition. Synechococcus strains have a ubiquitous oceanic distribution compared to that of Prochlorococcus strains and are characterized by phylogenetically discrete lineages with a wide range of pigmentation. In this review, we put our current knowledge of marine picocyanobacterial genomics into an environmental context and present previously unpublished genomic information arising from extensive genomic comparisons in order to provide insights into the adaptations of these marine microbes to their environment and how they are reflected at the genomic level.

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“…are pale green and contain chlorophyll b in addition to chlorophyll a, but completely lack all phycobilin pigments (cf. Partensky & Garczarek, 2003). A molecular phylogenic analysis, based on 16S rRNA, indicated that in 22 strains of Prochloron isolated from different species of didemnid ascidians around the Pacific Ocean both host specificity and biogeographic variation were unexpectedly low (Mu¨nchhoff et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Ultrastructural and microspectrophotometric characterization of multiple species of cyanobacterial photosymbionts coexisting in the colonial ascidianTrididemnum clinides(Tunicata, Ascidiacea, Didemnidae)

Hirose

Uchida

Murakami

2009

European Journal of Phycology

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Trididemnum clinides is a multi-photosymbiotic ascidian that inhabits shallow coral reef lagoons. Three types of cyanobacteria are harboured in the tunic of the ascidian colony; of these, two are unicellular coccoid cyanobacteria and the other is a multicellular filamentous type. They also differ in ultrastructure and distribution patterns within the host tunic. Microspectrophotometric analysis revealed the composition of photosynthetic pigments in each photosymbiont. One of the coccoid types is yellowish-green and is distributed under the colony surface. This photosymbiont cell preferentially absorbs red and blue light, and therefore the dominant colour in the inner tunic is green. The other two types of coexisting photosymbionts contain the green-light-absorbing R-phycoerythrin as the major photosynthetic pigment; they exploit the wavelengths of light not used by the first type of photosymbiont. In T. clinides, the outer and inner photosymbionts in the tunic have different photosynthetic pigments, which adapt to each microhabitat, thereby sharing the incident light resources effectively.

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The Photosynthetic Apparatus of Chlorophyll b- and d-Containing Oxyphotobacteria

Cited by 43 publications

References 167 publications

Streamlined Regulation and Gene Loss as Adaptive Mechanisms in Prochlorococcus for Optimized Nitrogen Utilization in Oligotrophic Environments

Streamlined Regulation and Gene Loss as Adaptive Mechanisms in Prochlorococcus for Optimized Nitrogen Utilization in Oligotrophic Environments

Ecological Genomics of Marine Picocyanobacteria

Ultrastructural and microspectrophotometric characterization of multiple species of cyanobacterial photosymbionts coexisting in the colonial ascidianTrididemnum clinides(Tunicata, Ascidiacea, Didemnidae)

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