title: PAHs reduce DNA synthesis and delay cell division in the widespread  primary producer Prochlorococcus.
abstract: The cyanobacteria Prochlorococcus is the most abundant primary producer in the ocean. In a global study across the Atlantic, Indian and Pacific Oceans, we tested the effect of organic pollutants on the growth and cell division of natural Prochlorococcus populations. Sub-lethal concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) altered Prochlorococcus cell division by reducing DNA synthesis and decreasing the percentage of cells entering mitosis. Cell division time increased with PAHs dosage by 1.2 h per μg L(-1) of mixture added. At PAHs dosages >1 μg L(-1), Prochlorococcus cell division tended to arrest at S-phase (DNA synthesis). As a consequence, population growth was significantly reduced in the presence of PAHs. The presence of PAHs resulted in a predictable alteration of the cell cycle of the widespread cyanobacteria.The dosages tested are above concentrations in the open ocean, but found in the coastal ocean, where Prochlorococcus growth must be inhibited.
authors.affiliation: Department of Global Change Research, IMEDEA (CSIC-UIB), Instituto Mediterraneo de Estudios Avanzados, Miquel Marques 21, 07190 Esporles, Spain.mcerezo@imedea.uib-csic.es
authors.forename: Maria Isabel
authors.initials: MI
authors.lastname: Cerezo
authors.forename: Susana
authors.initials: S
authors.lastname: Agustí
mesh_terms: D002453:Cell Cycle; D002455:Cell Division / Q000187:drug effects*; D000458:Cyanobacteria; D004247:DNA / Q000378:metabolism; D010140:Pacific Ocean; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000633:toxicity*; D048929:Prochlorococcus / Q000187:drug effects* / Q000235:genetics; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D004247:DNA