IJUP08 - Universidade do Porto

Characterisation of the Planctomycetes Pirellula sp. OJF20 and
Pirellula sp. OJF27 isolated from the surface of macroalgae
F. Viana 1 , J. Torres 1 , R. Abreu 1 , J. Bondoso 1,2 and O. Lage 1,2
1 Departamento de Botânica, Faculdade de Ciências Universidade do Porto, Portugal.
2 CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental
Planctomycetes are a morphologic and phylogenetic distinct group of the domain Bacteria.
Members of this group are characterised by budding, cellular compartmentalization and
absence of peptidoglycan in the cell wall, features that place Planctomycetes in a very
intriguing place in the evolution of microorganisms. Molecular and ecological studies
provided evidence about their abundance in a great diversity of habitats underlying their
important role in the ecology of the ecosystems [1]. They have been described in probable
association with sponges, crustacean, prawns, microalgae and Cyanobacteria. However
little is known about this group due to the relatively few species grown in pure culture thus
the great importance of isolation and cultivation studies for its better understanding. OJF
Planctomycetes culture collection has, presently, about 200 strains, the majority isolated
from the surface of different macroalgae [2]. Pirellula sp. OJF20 and Pirellula sp. OJF27
are strains isolated from the surface of Corallina sp. and Condrus crispus, respectively.
Corallina was collected in Foz (Porto, Portugal) and C. crispus in Carreço (Viana do
Castelo, Portugal), areas with different levels of pollution. Both strains are closely related
and placed in a new cluster of Planctomycetes. DNA-based fingerprinting methods (16S
rDNA analysis and BOX-PCR), growth in liquid medium and physiological studies (range
of temperature, pH, salinity, and nutritional requirements) were performed in order to
allow a comparison between the two strains. Despite the 98% 16S rDNA sequence
similarity between the two strains that places them in the same species, they present
significant metabolic and physiologic differences and are adapted to diverse environmental
conditions.
[1] Fuerst, J. A. 1995. The planctomycetes: emerging models for microbial ecology, evolution, and
cell biology. Microbiology 141:1493-1506;
[2] Lage OM, Bondoso J. 2007. Marine Planctomycetes-Macroalgae Association from the Atlantic
North Coast of Portugal. Presented at Sustainable Neighborhood - from Lisbon to Leipzig through
Research (L2L), Leipzig.
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