title: A Novel Antifouling Defense Strategy from Red Seaweed: Exocytosis and Deposition of Fatty Acid Derivatives at the Cell Wall Surface.
abstract: We investigated the organelles involved in the biosynthesis of fatty acid (FA) derivatives in the cortical cells of Laurencia translucida (Rhodophyta) and the effect of these compounds as antifouling (AF) agents. A bluish autofluorescence (with emission at 500 nm) within L. translucida cortical cells was observed above the thallus surface via laser scanning confocal microscopy (LSCM). A hexanic extract (HE) from L. translucida was split into two isolated fractions called hydrocarbon (HC) and lipid (LI), which were subjected to HPLC coupled to a fluorescence detector, and the same autofluorescence pattern as observed by LSCM analyses (emission at 500 nm) was revealed in the LI fraction. These fractions were analyzed by gas chromatography-mass spectrometry (GC-MS), which revealed that docosane is the primary constituent of HC, and hexadecanoic acid and cholesterol trimethylsilyl ether are the primary components of LI. Nile red (NR) labeling (lipid fluorochrome) presented a similar cellular localization to that of the autofluorescent molecules. Transmission and scanning electron microscopy (TEM and SEM) revealed vesicle transport processes involving small electron-lucent vesicles, from vacuoles to the inner cell wall. Both fractions (HC and LI) inhibited micro-fouling [HC, lower minimum inhibitory concentration (MIC) values of 0.1 µg ml(-1); LI, lower MIC value of 10 µg ml(-1)]. The results suggested that L. translucida cortical cells can produce FA derivatives (e.g. HCs and FAs) and secrete them to the thallus surface, providing a unique and novel protective mechanism against microfouling colonization in red algae.
authors.affiliation: Diretoria de Pesquisas, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, 22460-030, Brazil.
authors.forename: Wladimir Costa
authors.initials: WC
authors.lastname: Paradas
authors.affiliation: Diretoria de Pesquisas, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, 22460-030, Brazil.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Tavares Salgado
authors.affiliation: Departamento de Biologia Marinha, Universidade Federal Fluminense, Niterói, 100644, Brazil.
authors.forename: Renato Crespo
authors.initials: RC
authors.lastname: Pereira
authors.affiliation: Biodimar/LEMAR/IUEM, Université de Bretagne Occidentale (UBO), 6 Avenue Victor Le Gorgeu, CS93837, Brest cedex 3 29238, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Hellio
authors.affiliation: Departamento de Bioquimica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-590, Brazil.
authors.forename: Georgia Correa
authors.initials: GC
authors.lastname: Atella
authors.affiliation: Instituto de Tecnologia em Fármacos, Instituto Oswaldo Cruz, Rio de Janeiro, 21041-250, Brazil.
authors.forename: Davyson
authors.initials: D
authors.lastname: de Lima Moreira
authors.affiliation: Instituto de Tecnologia em Fármacos, Instituto Oswaldo Cruz, Rio de Janeiro, 21041-250, Brazil.
authors.forename: Ana Paula Barbosa
authors.initials: AP
authors.lastname: do Carmo
authors.affiliation: Núcleo de Pesquisas em Ecologia e Desenvolvimento Social de Macaé, Universidade Federal do Rio de Janeiro, Macaé, 27910-970, Brazil.
authors.forename: Angélica Ribeiro
authors.initials: AR
authors.lastname: Soares
authors.affiliation: Diretoria de Pesquisas, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, 22460-030, Brazil gfilho@jbrj.gov.br.
authors.forename: Gilberto
authors.initials: G
authors.lastname: Menezes Amado-Filho
mesh_terms: D001692:Biological Transport; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism; D005089:Exocytosis; D005227:Fatty Acids / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D008826:Microbial Sensitivity Tests; D000461:Rhodophyta / Q000737:chemistry / Q000502:physiology*; D014617:Vacuoles / Q000378:metabolism
chemical_list: D005227:Fatty Acids
keywords: Antifouling; Fatty acid derivatives; Hydrocarbons; Laurencia translucida; Storage compounds; Vacuoles