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Diel rhythmicity in amino acid uptake by Prochlorococcus

By Isabelle Mary, Laurence Garczarek, Glen A. Tarran, Christian Kolowrat, Matthew J. Terry, David J. Scanlan, Peter H. Burkill and Mikhail V. Zubkov


The marine cyanobacterium Prochlorococcus, the most abundant phototrophic organism on Earth, numerically dominates the phytoplankton in nitrogen (N)-depleted oceanic gyres. Alongside inorganic N sources such as nitrite and ammonium, natural populations of this genus also acquire organic N, specifically amino acids. Here, we investigated using isotopic tracer and flow cytometric cell sorting techniques whether amino acid uptake by Prochlorococcus is subject to a diel rhythmicity, and if so, whether this was linked to a specific cell cycle stage. We observed, in contrast to diurnally similar methionine uptake rates by Synechococcus cells, obvious diurnal rhythms in methionine uptake by Prochlorococcus cells in the tropical Atlantic. These rhythms were confirmed using reproducible cyclostat experiments with a light synchronised axenic Prochlorococcus (PCC9511 strain) culture and 35S-methionine and 3H-leucine tracers. Cells acquired the tracers at lower rates around dawn and higher rates around dusk despite >104 times higher concentration of ammonium in the medium, presumably because amino acids can be directly incorporated into protein. Leucine uptake rates by cells in the S+G2 cell cycle stage were consistently 2.2 times higher than those of cells at the G1 stage. Furthermore, S+G2 cells up-regulated amino acid uptake 3.5 times from dawn to dusk to boost protein synthesis prior to cell division. Because Prochlorococcus populations can account from 13% at midday, and up to 42% at dusk, of total microbial uptake of methionine and probably of other amino acids in N-depleted oceanic waters, this genus exerts diurnally variable, strong competitive pressure on other bacterioplankton populations

Topics: QL, QR
Publisher: Blackwell
Year: 2008
OAI identifier:

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  1. (1988). A novel free-living prochlorophyte abundant in the oceanic euphotic zone. doi
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  3. (1995). Amino acid transport systems required for diazotrophic growth in the cyanobacterium Anabaena sp. strain PCC7120. doi
  4. (2005). Amino acid uptake of Prochlorococcus spp. in surface waters across the South Atlantic Subtropical Front. doi
  5. (2005). Assimilation efficiency of Vibrio bacterial protein biomass by the flagellate Pteridomonas: assessment using flow cytometric sorting. doi
  6. (2001). Cell cycle regulation by light in Prochlorococcus strains. doi
  7. (1991). Circadian-rhythm in amino acid uptake by Synechococcus RF-1. doi
  8. (1997). Enumeration and cell cycle analysis of natural populations of marine picoplankton by flow cytometry using the nucleic acid stain SYBR Green I.
  9. (2003). Genome divergence in two Prochlorococcus ecotypes reflects oceanic niche differentiation. doi
  10. (1995). Growth of Prochlorococcus, a photosynthetic prokaryote, in the equatorial Pacific Ocean. doi
  11. (2003). High rate of uptake of organic nitrogen compounds by Prochlorococcus cyanobacteria as a key to their dominance in oligotrophic oceanic waters. doi
  12. (2008). Light enhanced amino acid uptake by dominant bacterioplankton groups in surface waters of the Atlantic Ocean. doi
  13. (2007). Microbial control of phosphate in the nutrient-depleted North Atlantic subtropical gyre. doi
  14. (2007). Patterns and implications of gene gain and loss in the evolution of Prochlorococcus. doi
  15. (1992). Phytoplankton size. In Primary productivity and biogeochemical cycles in the doi
  16. (1994). Primary production of prochlorophytes, cyanobacteria, and eukaryotic ultraphytoplankton - measurements from flow cytometric sorting. doi
  17. (2007). Prochlorococcus contributes to new production in the Sargasso Sea deep chlorophyll maximum. doi
  18. (1999). Prochlorococcus, a marine photosynthetic prokaryote of global significance. doi
  19. (2002). Resolution of Prochlorococcus and Synechococcus ecotypes by using 16S-23S ribosomal DNA internal transcribed spacer sequences. doi
  20. (2004). Streamlined regulation and gene loss as adaptive mechanisms in Prochlorococcus for optimised nitrogen utilization in oligotrophic environments. doi
  21. (2000). subsp. pastoris subsp. nov. strain PCC 9511, the first axenic chlorophyll a2/b2-containing cyanobacterium (Oxyphotobacteria).
  22. (1997). The role of nitrogen fixation in biogeochemical cycling in the subtropical North Pacific Ocean. doi
  23. (2002). Utilisation of different nitrogen sources by the marine cyanobacteria Prochlorococcus and Synechococcus. doi

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