**9. References**


http://www.vnwatersectorreview.com/detail.aspx?pid=107&r=5#4


**4** 

*Portugal* 

**Risk Assessment of Cyanobacteria and** 

**of** *Planktothrix* **spp. Monitoring** 

*Nacional de Saúde Dr. Ricardo Jorge, Lisboa,* 

*Universidade Nova de Lisboa, Caparica,* 

Catarina Churro1,2, Elsa Dias1 and Elisabete Valério2

**Cyanotoxins, the Particularities and Challenges** 

*1Laboratório de Biologia e Ecotoxicologia, Departamento de Saúde Ambiental, Instituto* 

Cyanobacteria are a diverse well adapted group of organisms that presents amazing morphological diversity. Cyanobacteria can be unicellular or colonial (filamentous, spherical or amorphous) (Fig. 1). Since cyanobacteria have cells larger than normal bacterial cells and behavior more similar to algae, they were classified under the microalgae for a long time and acquire the name of blue-green algae or Cyanophyta (Whitton & Potts 2000). Cyanobacteria is a phylum of bacteria that obtain their energy through photosynthesis. The name "cyanobacteria" comes from their coloration (cyano = blue). The vegetative cell wall is of Gram-negative type and in some species the peptidoglycan layer is considerably thicker than in other bacteria. Many unicellular and filamentous cyanobacteria possess an "envelope" outside the lipopolysaccharide (LPS) "outer membrane", which is called: sheath, glycocalyx, or capsule, and depending on the consistency, gel, mucilage or slime. The sheaths of cyanobacteria are predominantly polysaccharide, but a part of its weight may be polypeptides, and depending on the species, some types of sugar residues may be involved

Fig. 1. Optical microscopy photographs of cyanobacteria presenting different morphologies.

The arrow indicates the heterocyst cell in *Anabena circinalis*.

**1. Introduction** 

(Castenholz, 2001).

*2Centro de Recursos Microbiológicos (CREM), Faculdade de Ciências e Tecnologia,* 

