Twelve populations of filamentous, heterocytous scytonematoid cyanobacteria from subaerophytic (mainly epiphytic) habitats in subtropical and tropical Brazil (São Paulo) were studied. The populations form a uniform cluster, which differs from the traditional scytonematoid genera genetically and by several indistinct, but typical morphological characters (fasciculation of filaments, rare false branching). Two strains were isolated in monospecific cultures. Molecular analyses were performed on these strains from natural populations taken from bromeliad leaves and iron water pipes. Because the results from 16S rRNA gene sequencing indicated the separate position of this cyanobacterium at the generic level, a new genus, Brasilonema, is proposed with the type species Brasilonema bromeliae. The new genus is described using combined molecular and cytomorphological criteria, in accordance with the nomenclatorial recommendations of both the Bacteriological Code and the Botanical Code of Nomenclature (cf. Oren 2004). The ultrastructure of the type species was studied, and vacuole-like structures in the cells were explained. The genus Brasilonema is commonly distributed, particularly in subaerophytic habitats from southeastern Brazil. The type species (B. bromeliae) has a rather curious ecology, living epiphytically (in phytothelmes) inside the vase-shaped leaf rosettes of bromeliads.

Based on the literature about the cyanobacteria from Brazil and particularly from São Paulo State, the list of Brazilian flora and the data bank of herbaria collections, a total of 460 species were referred to Brazil and 378 to São Paulo State. Taking into account that the group of cyanobacteria presents around 2800 species, these numbers represent much less than 20% of the known species. Considering the diversity of environments and habitats in the tropical/subtropical biomes compared to the reduced number of known species, this biodiversity is certainly underestimated and should be much larger.

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-(Cyanobacterial occurrence and detection of microcystins by planar chromatography in surface water of Billings and Guarapiranga Reservoirs, SP, Brazil). Billings and Guarapiranga Reservoirs were deeply affected by environmental disturbances, which more evident consequence are the cyanobacterial blooms. Microcystins are the most common cyanotoxin in freshwaters and more than 70 types are known. Different methods for microcystins analysis in water can be used, among which ELISA and HPLC are the most frequently employed. However, less sophisticated and more economic methods can also be used. This is the case of planar chromatography (thin-layer chromatography) method previously used in cyanotoxins purification but gradually replaced by others. Posterior optimization of the microcystin chromatography conditions and because of its simplicity, rapidity, efficiency and low cost, this method is again considered an option for the analysis of microcystins and nodularins. Considering the importance of Billings and Guarapiranga Reservoirs for drinking water supplies and the few scientific data about cyanobacteria and cyanotoxins in these water bodies, the aims of this work are to analyze the biodiversity of cyanobacteria in the Billings and Guarapiranga Reservoirs and the detection of dissolved microcystins in the water. It was possible to identify 17 species of cyanobacteria, 9 of them being potentially toxic. In Billings Reservoir Microcystis aeruginosa (Kützing) Kützing and Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba Raju are the most common species, while in Guarapiranga Reservoir only M. aeruginosa was considered as a common species. Microcystins were detected in all Billings Reservoir samples and in only one sample from Guarapiranga Reservoir.Key words -cyanobacteria, drinking water, microcystins, planar chromatography, reservoirs RESUMO -(Ocorrência de cianobactérias e detecção por cromatografia planar de microcistinas dissolvidas nas águas superficiais das represas Billings e de Guarapiranga, SP, Brasil). As represas Billings e Guarapiranga foram profundamente afetadas por fatores ambientais cuja conseqüência mais evidente são as florações de cianobactérias. As microcistinas formam a classe de cianotoxinas mais freqüente em água doce e são comumente analisadas por ELISA ou CLAE. No entanto, processos menos sofisticados e mais econômicos também podem ser usados. Este é o caso da cromatografia planar (cromatografia em camada delgada), método anteriormente usado em trabalhos de purificação de cianotoxinas, mas que foi gradualmente substituído por outros. Assim, considerando a importância das represas Billings e Guarapiranga para o abastecimento público e a carência de informações científicas sobre as cianobactérias e as cianotoxinas que nelas ocorrem, nossos objetivos foram o estudo da composição desses organismos e a detecção de microcistina dissolvida na água. Foi possível identificar 19 espécies de cianobactérias, das quais 9 são consideradas potencialmente tóxicas. Microcystis aeruginosa...

-(Planktic Cyanobacteria from upper Tietê basin reservoirs, SP, Brazil). Considering the great ecological and sanitary importance of the cyanobacteria and the need of detailed information about these organisms in Brazilian water bodies, the present study aims at contributing towards the knowledge of the cyanobacterial flora of five reservoirs belonging to the upper Tietê Basin, São Paulo: Billings, Guarapiranga, Jundiaí, Pirapora, Ponte Nova and Taiaçupeba. In the past several years, these reservoirs have been submitted to severe environmental deterioration and have repeatedly presented cyanobacterial blooms, including those of toxic species. The samples were collected between 1997 and 2003 either with plankton net (20 µm mesh) or van Dorn´s bottle, and preserved with lugol solution or formaldehyde. Some species were isolated and maintained in culture. Forty-eight species of cyanobacteria were identified, with predominance of the order Chroococcales (58%), followed by the orders Oscillatoriales (21%) and Nostocales (21%). Among the 48 studied species, 17 (35%) were considered potentially toxic. The occurrence and biodiversity of the cyanobacteria in each reservoir depend on the environmental conditions. Among the five water bodies, Billings Reservoir presented the most adequate situation for the development of a greater number of species (34), probably due to its high pH values (around 8). Pirapora Reservoir on the other hand, with highest conductivity (445.0 µS cm -1 ) and lowest Secchi depth values (0.2 m), presented the lowest cyanobacterial biodiversity (14 species).Key words -Brazil, diversity, planktic Cyanobacteria, reservoirs RESUMO -(Cianobactérias planctônicas em reservatórios do Alto Tietê, SP, Brasil). Diante da grande importância ecológica e sanitária das cianobactérias e da escassez de informações mais detalhadas sobre estes organismos em corpos d´água doce brasileiros, o presente trabalho pretende estudar a flora de cianobactérias em cinco represas da Bacia Hidrográfica do Alto Tietê, São Paulo. As represas Billings, Guarapiranga, Jundiaí, Pirapora, Ponte Nova e Taiaçupeba vêm sofrendo, nos últimos anos, forte deterioração ambiental e têm apresentado repetidas florações de cianobactérias, inclusive tóxicas. As amostras foram coletadas entre 1997 e 2003 com rede de plâncton (abertura da malha de 20 µm) ou garrafa do tipo van Dorn, e preservadas com lugol ou formalina. Algumas espécies foram isoladas e mantidas em cultura. Foram identificadas 48 espécies de cianobactérias, com predominância da ordem Chroococcales (58%), seguida das ordens Oscillatoriales (21%) e Nostocales (21%). Entre as 48 espécies estudadas, 17 (35%) são consideradas potencialmente tóxicas. A biodiversidade e distribuição das cianobactérias em cada reservatório relacionam-se com as condições ambientais dos mesmos. A Represa Billings mostrou-se o ambiente mais propício ao desenvolvimento de maior número de espécies (34), provavelmente em função de seu pH elevado (em torno de 8). Já o Reservatório de Pirapora, com os valor...

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