Marine cyanobacteria have emerged as a source of promising bioactive compounds. The isolation of strains from tropical environments seems to be an important step in the search for molecules displaying bioactivity, besides being valuable for biotechnological purposes. Thus, the objective of the present study was to describe marine cyanobacterial strains, isolated and characterized in terms of morphology and molecular phylogeny, as well as screened for biologically active compounds. Five strains were isolated and morphologically characterized as Leptolyngbya (CENA553, CENA554 and CENA555) and Geitlerinema (CENA552 and CENA556). Considering the phylogenetic results, these strains did not match the clusters of the type-species or reference strains, indicating the possible emergence of new generic entities morphologically related to Leptolyngbya and Geitlerinema. Among the isolated strains, CENA552 and CENA556 were selected for chemical analyses. Five known nucleosides with biological activities and two amino acids were recognized and isolated from the CENA556 strain. The GC-MS analyses of strains CENA552 and CENA556 revealed distinct classes of non-polar compounds, with a predominance of octadecane (CENA556), 2-hexyl-1-decanol (CENA552) and neophytadiene (CENA552 and CENA556) hydrocarbons. All nucleosides and amino acids were highly abundant, indicating these morphotypes as promising sources of these bioactive compounds. This is the first report considering taxonomy/molecular phylogeny as well as chemistry prospection of morphotypes resembling Geitlerinema-like isolated from the Brazilian coastal area, highlighting the potential of these taxa for biotechnological applications.

Estudo químico de cianobactérias marinhas e do cultivo misto entre a linhagem Geitlerinema sp CENA556 e o fungoMarine organisms are recognized as a rich reservoir of natural products with exceptional molecular structures. In this context, cyanobacteria and endophytic fungi has emerged as source of promising bioactive compounds. The aim of this work was to look for biologically active compounds from the marine cyanobacteria strains, collected in Ubatuba, coast of the São Paulo state (Brazil), and to explore the biosynthetic potential of the fungus Trichoderma atroviride (endophyte isolated from marine seaweed Bostrychia tenella, collected in the rocky Shore of Praia de Fortaleza, Ubatuba, SP) by coculture with the cyanobacteria strain Geitlerinema sp CENA556. Initially, five species of marine cyanobacteria were isolated from the sample collected at the coast of São Paulo, and then characterized phylogenetically. Among them, the strains coded as Geitlerinema sp CENA552 and Geitlerinema sp CENA556 were cultured in mimicking seawater medium and extracted with a mix of CH 2 Cl 2 / MeOH (2:1), and then EtOAc. The concentrated extract was partitioned into hexane fraction and MeOH/H2O (95: 5) fraction. Four known compounds were identified from the hexane fraction of the Geitlerinema sp CENA552 extract by GC-MS analysis: 2-hexyl-1-decanol, 3-octadecene, neophytadiene, and methyl palmitate. Similarly, the compounds dodecanal, 8-heptadecene, palmitaldehyde, neophytadiene, phytol, methyl palmitoleate, methyl 7-hexadecenoate, and methyl 9-hexadecenoate were identified from the hexane fraction of the Geitlerinema sp CENA556 extract. Starting of MeOH/H2O (95: 5) fraction of Geitlerinema sp CENA556 extract, seven compounds were isolated by semi preparative HPLC-PDA and identified by NMR spectroscopy and HR-MS analysis. Among them, five known nucleosides first isolated from cyanobacteria: 2'-deoxyuridine, thymidine, adenosine, 2'-deoxyadenosine, and uridine. Also two amino acids: D-leucine and L-phenylalanine. Trichoderma atroviride was grown alone in rice and Czapeck media and the coculture between the fungus and the cyanobacteria (Geitlerinema sp CENA556) were performed using the same media. The CH 2 Cl 2 / MeOH (2:1) and EtOAc pooled extract from the coculture of the fungus T. atroviride and the cyanobacteria Gleiterinema sp CENA556 in Czapek medium shows significant difference in the metabolites production when compared to individually cultured fungus and cyanobacteria. Four catechol type siderophores were isolated from MeOH/H2O (95: 5) fraction of this extract: agrobactin, agrobactin A, photobactin and one novel compound. Agrobactin, the major compound, showed substantial antibacterial activity against P. mirabilis, E. coli, S. saprophyticus, S. aureus and P. aeruginosa. Thus, the studied brazilian cyanobacteria Geitlerinema sp appeared to be promising for isolation of nucleosides with biological activity. Furthermore, the fungus T. atroviride proved to be a prolific source of antibacterial siderophores obtained by biologic...