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SUMMARY: The antibacterial and antifungal activity of 82 marine macroalgae (18 Chlorophyceae, 25 Phaeophyceae and 39 Rhodophyceae) was studied to evaluate their potential for being used as natural preservatives in the cosmetic industry. The bioactivity was analysed from crude extracts of fresh and lyophilised samples against three Gram-positive bacteria, two Gram-negative bacteria and one yeast using the agar diffusion technique. The samples were collected seasonally from Mediterranean and Atlantic coasts of the Iberian Peninsula. Of the macroalgae analysed, 67% were active against at least one of the six test microorganisms. The highest percentage of active taxa was found in Phaeophyceae (84%), followed by Rhodophyceae (67%) and Chlorophyceae (44%). Nevertheless, red algae had both the highest values and the broadest spectrum of bioactivity. In particular, Bonnemaisonia asparagoides, Bonnemaisonia hamifera, Asparagopsis armata and Falkenbergia rufolanosa (Bonnemaisoniales) were the most active taxa. Bacillus cereus was the most sensitive test microorganism and Pseudomonas aeruginosa was the most resistant. The highest percentages of active taxa from Phaeophyceae and Rhodophyceae were found in autumn, whereas they were found in summer for Chlorophyceae.Keywords: antimicrobial activity, marine macroalgae, Bonnemaisoniales, agar diffusion technique, crude extracts, Iberian Peninsula.RESUMEN: ACTIVIDAD ANTIMICROBIANA DE MACROALGAS MARINAS DE LA PENÍNSULA IBÉRICA. -Se analizó la actividad antibacteriana y antifúngica de 82 macroalgas marinas (18 Chlorophyceae, 25 Phaeophyceae y 39 Rhodophyceae) para valorar su potencial aplicación como conservantes naturales en la industria cosmética. Los extractos crudos de cada taxon, preparados tanto a partir de material fresco como liofilizado, fueron testados frente a tres bacterias Gram positivas, dos bacterias Gram negativas y una levadura, mediante la técnica de difusión en agar. Las muestras fueron recolectadas en diversas localidades de las costas mediterráneas o atlánticas de la Península Ibérica en distintas estaciones del año. El 67% de todas las macroalgas estudiadas mostraron actividad antimicrobiana frente al menos un microorganismo test de los seis utilizados. El mayor porcentaje de táxones activos lo presentó el grupo de las Phaeophyceae (84%) seguido por las Rhodophyceae (67%) y por las Chlorophyceae (44%). No obstante, las algas rojas fueron las que presentaron el mayor grado de actividad así como el espectro de acción más amplio y, dentro de este grupo, Bonnemaisonia asparagoides, Bonnemaisonia hamifera, Asparagopsis armata y Falkenbergia rufolanosa (Bonnemaisoniales) fueron los táxones más activos. En cuanto a los microorganismos, Bacillus cereus fue el más sensible y Pseudomonas aeruginosa el más resistente. Los tres grupos taxonómicos mostraron una variación estacional en la producción de sustancias antimicrobianas, siendo el otoño la estación con mayor porcentaje de táxones activos para las Phaeophyceae y Rhodophyceae, mientras que para las Chlorophyceae fue...

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Despite the fact that brown algae are critical components of marine ecosystems around the world only one species has had its genome sequenced. To facilitate genome studies in the class we report data for 12 of the 19 recognized orders.

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Dictyota cyanoloma has recently been described from the Mediterranean Sea and Macaronesia but doubt had arisen as to whether this species was truly native in Europe. The species is mainly found on non-natural substrata (harbour walls, marinas, boat hulls, etc.), strongly suggesting that it is an introduction. Molecular sequence information from historical herbarium samples proves the presence of D. cyanoloma in the Adriatic Sea as early as 1935. Since approximately the year 2000, however, the number of records as well as the geographic range of the species has expanded significantly. The presentday distribution of D. cyanoloma occupies most of the Mediterranean Sea, Macaronesia, NW Africa and southern Portugal, but recent records from Galicia and SW England (Falmouth, Cornwall) indicate that the species is rapidly expanding northward. Collections from Australia demonstrated that the species is also present from Perth in Western Australia, over much of the southern Australian coastline up to Minnie Water in New South Wales. Phylogenetic analyses resolve D. cyanoloma in a sister clade to a previously unreported Australian Dictyota species. Analysis of genetic diversity of the mitochondrial markers (nad6-nad11 and atp9-orf11) reveals that even though Australian populations contain a much higher haplotype richness, European populations are also fairly diverse. Furthermore, only two out of 25 haplotypes are shared between both regions. These somewhat counterintuitive results could be indicative of a more complicated introduction history

Genetic affiliation, nuclear DNA content, and gamete functioning were examined in small salt marsh Fucus from three localities in western Ireland. Individuals with small and dioecious receptacles were found at all localities, but production of germlings was only evident from those at Locality 1. Here, the Fucus vegetation formed a morphological cline from F. vesiculosus with bladders in the mid-intertidal to small Fucus individuals lacking bladders in the salt marsh of the upper intertidal. Measurements of nuclear DNA content ranged from 1-1.8 pg at this locality, with the F. vesiculosus individuals in the lower range. At the two other localities, the small salt marsh Fucus formed distinct morphological entities. Microsatellite analyses revealed that the small salt marsh Fucus individuals from Locality 2 were derived mainly from F. vesiculosus, whereas those from Locality 3 were hybrids between F. vesiculosus and F. spiralis with greatest affiliation to F. spiralis. While the small salt marsh Fucus forms from Locality 2 had high nuclear DNA content (ca. 4 pg) and were probably octoploids, the small salt marsh Fucus from Locality 3 formed two groups: one with high (3.9-4.6 pg) and one with low (1.5-1.9 pg) nuclear DNA content. Nuclear DNA content measured in individuals from Locality 3 varied between 1.1-2.8 pg in F. vesiculosus and 2-3.5 pg in F. spiralis, and showed a more or less stepwise increase in both species, consistent with polyploidy. We hypothesize that the small salt marsh Fucus forms originate from genome size changes in the parental taxa.