Planctomycetes

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Planctomycetes

• Deanna
• Aragona-Barr
• Photo University of Nijmegen

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Introduction

• First described by Gimesi (1924) in Budapest,
  Hungary
• Mistakenly identified as planktonic fungus
• Schlesner and Stackebrandt (1986) assign
  Planctomyces and Pirellua to order
  Planctomycetales

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What Makes them Unique

• No peptidoglycan in cell wall-antibiotic
  resistant
• Crateriforms pits
• Budding
• Short 5S rRNA
• Nonprosthecate appendages stalks (some)
• Spherical to ovoid shape
• Very slow growing

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Habitats

• Originally only in water fresh water, marine,
  brackish, hypersaline
• Marine organic aggregates (marine snow)
• Soil
• Sewage sludge
• Crustacean gut
• Microbial mats
• Very difficult to culture

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Known Genera

• Planctomyces- form rosettes or single
  cell-freshwater, marine,hypersaline
• Gemmata-single cell-membrane-bound nuclear
  body-freshwater
• Piruella-form rosettes-membrane-bound cell
  compartment -freshwater, brackish
• Isospheara-filamentous-hotsprings-gliding

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Three New Genera Candidates

• Candidatus Brocadia anammoxidans
• Candidatus Kuenenia stuttgartiensis
• Candidatus Scalindua brodae
• Candidatus Scalindua sorokinii

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Pl. bekefii
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Pirellula marina
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• Aerobic chemoorganoheterotrophs Planctomyces,
  Pirellula, Gemmata, and Isosphaera
• Anaerobic ammonium-oxidizing anaerobic
  chemolithoautotrophs (Anammox)

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Giant Tiger Prawn Penaeus monodon

• Pirellua-like bacteria found in midgut (Fuerst et
  al., 1991)
• Identified using Planctomycete specific 16S rRNA
  directed probes (Fuerst et al., 1997)
• Found 5 clones in Pirellula group and 1 clone in
  the Planctomyces group

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Anammox

• Anaerobic Ammonia Oxidation
• NH4 NO2- gt N2 2H2O
• Anammox process confirmed and verified Mulder et
  al., 1995, Jetten et al., 1999
• Identified as planctomycete (Strous et al., 1999)

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Identification

• Membrane-bound compartments
• Crateriform structures
• 16S rRNA deep-branching planctomycete
  (74-77 sequence identity)

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Anammox Tree
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Candidatus Brocadia anammoxidans
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Anammox process

• Anaerobic anammox completely inhibited at low
  oxygen concentrations
• Enzyme hydroxylamine oxidoreductase catalyzes
  oxidation of hydrazine and hydroxylamine
• Located in membrane-bound structure called
  anammoxosome
• Membrane surrounding anammoxosome made up of
  ladderane lipids (unique)

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Latest Discovery (Kuypers et al., 2003)

• Black Sea Worlds largest anoxic basin
• High ammonium concentration that drops at suboxic
  zone
• Ladderane lipids detected at suboxic zone
• 16S rRNA 87.9 similarity to Kuenenia and 87.6
  similarity to Brocadia

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Candidatus Scalindua sorokinii
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Ecological Significance

• Anammox - nitrogen cycling in oceans
• Anammox biological wastewater treatment
• Pl. bekefii may serve as indicator of eutrophic
  conditions
• Widely distributed