Search

BackgroundMarine bacteria have recently attracted increasing attention to be harnessed for the production of valuable enzymes, vitamins, and bioactive compounds. Bacteria associated with the surfaces of marine macroalgae, called epibionts, are particularly interesting from ecological and biotechnological points of view, as they often exhibit antimicrobial activities to compete with pathogenic bacteria for nutrients and spaces. In search for biotechnologically potential genes from marine bacteria, we sequenced and analysed the genome of the epibiont HI03-3b, a polysaccharide-degrading bacterium associated with the surface of the Indonesian brown algae Hydroclathrus sp.ResultsThe algal epibiont HI03-3b has a genome of approximately 4,860,704 bp in size with 42.02 mol% G + C content, consisting of 5655 open reading frames (ORFs), 4409 genes coding for proteins (CDSs), 94 genes for tRNAs, and 32 genes for rRNAs. The genome sequence of HI03-3b was most closely related to that of Cytobacillus firmus NCTC10335 with the average amino acid identity (AAI) of 95.0 %, average nucleotide identity (ANI) of 94.1 %, and a recommended DNA-DNA hybridization (DDH) of 57.60 %. These scores are lower than the most frequently used standard for species demarcation (95% ANI cutoff) and the new species threshold (DDH > 70.0% for the same bacterial species). Some differences in genome features and gene composition were observed between HI03-3b and NCTC10335, such as genes encoding carbohydrate active enzymes. These suggest that HI03-3b is unique and likely a novel species within Cytobacillus genus, and we therefore proposed its name as Cytobacillus wakatobiense HI03-3b. Genome sequence analyses indicated the presence of genes involved not only in polysaccharide and protein degradation but also in vitamin and secondary metabolite biosynthesis. Some of them encode enzymes and compounds with biotechnological interest, such as protease, chitinase, subtilisin, pullulanase, and bacillolysin, which

Seaweed is depicted as a future food in Western cultures, yet its introduction and expansion to new markets come with several challenges, including food neophobia and limited knowledge about its usability. To address these challenges, this study characterizes sensory perceptions, nutritional content, and physicochemical properties of four common northern European seaweed species, Saccharina latissima, Alaria esculenta, Palmaria palmata, and Ulva sp. These species are rich in minerals (25.8–36.8 %) and carbohydrates (29.6–54.6 %), especially dietary fibre (29.8–34.1 %), but have lower levels of dietary protein (6.7–11.4 %) and lipids (1.3–2.4 %). The amino acid profiles almost matched those of complete proteins, but with lower levels of histidine (Ulva sp. had also lower levels of lysine). All species were generally perceived to have high taste of saltiness, medium umami, low bitterness and sourness, and no sweetness. Overall, P. palmata stood out most from the other species with its red magenta colour, sea and shellfish odour, umami taste, and firm and chewy texture. Contrary, Ulva sp. was perceived as the saltiest species, with a lightness in colour and elements of yellow, an odour resembling lemon and fresh grass, and the least crispy, firm, and chewy texture. The two brown species, S. latissima and A. esculenta, were overall perceived as similar to each other. The mapping of seaweed's attributes in this study can be directly useful as knowledge for the improvement of future seaweed products and their availability in Western food cultures.

Marine algae are an important and historically rich source of new marine-based natural products. This thesis describes the screening of 40 Indonesian macroalgal samples using liquid chromatography-mass spectrometry (LC-MS) based molecular networking, and the subsequent nuclear magnetic resonance (NMR)-guided isolation and structural elucidation of a 6-deoxy-6-aminoglycoglyrecolipid (60). Molecular networking was performed using LC-MS/MS data through the online Global Natural Product Social Molecular Networking (GNPS) platform directly from crude extracts. NMR spectroscopy-guided screening was also employed targeting unique peaks detected by 1H NMR to validate any hits from GNPS. Out of 40 macroalgae specimens collected from West Timor waters, six samples were prioritised by the molecular networking screening. Proton NMR revealed three specimens with significantly interesting peaks but only one specimen, Laurencia snackeyi was purified further, which yielded compound 60.

The species composition and seasonal occurrence of the marine macroalgae on the central coast of Hiroshima Prefecture, specifically in the vicinity of Takehara, in the Seto Inland Sea of Japan were studied. A total of 143 species was identified including 18 species of Chlorophyceae, 43 species of Phaeophyceae, and 82 species of Rhodophyceae. Most species were seasonal and more abundant from February to July, when more than 60 species occurred in each month. March had 79 species, the highest species number in a single month. Ulva pertusa, Codium fragile, Ishige okamurae, Ecklonia kurome, Sargassum fusiforme, S. thunbergii, Corallina pilulifera, and Chondrus giganteus were found throughout the year. Of 143 species, Dictyota linearis, Sporochnus radiciformis, and Martensia fragilis were warm temperate species that reported in the Bungo-channel regions, while only Dictyota linearis can be found in the southern islands of subtropical Japan. The rest of the species were temperate species. There are 104 species commonly found on the coasts of Hiroshima Prefecture, representing the major algal communities along the coast of the Prefecture.

As global climates warm and habitats are modified, disease is emerging as a major threat to biodiversity. Understanding the causes and consequences of disease and the influence of environmental change on both host organisms and pathogens is critical for the conservation of important ecosystems. Current rates of environmental change are unprecedentedly rapid, due largely to anthropogenic disturbances, further necessitating the study of disease dynamics. In this thesis, I assessed the causes and consequences of a bleaching phenomenon afflicting a chemically-defended macroalga, Delisea pulchra. Broadly, the aims of this study were to characterise patterns of bleaching in D. pulchra and to assess whether they related (directly or indirectly) to environmental factors, either via influences on algal chemical defences and/or bacterial pathogens. Additionally, I aimed to understand the consequences of disease for D. pulchra and its trophic interactions. Bleaching was more common in summer when water temperatures were elevated and was also more prevalent in shallow water habitats than at depth. Bleached algae supported significantly different microbial communities on their surfaces and also had depleted chemical defences (furanones) compared to co-occurring, healthy conspecifics. Bleaching was more likely at high temperatures when algal chemical defences were low or absent, and microorganisms were abundant and this was evident both in natural populations and in experimental manipulations. Inoculation with a candidate pathogen, Ruegeria sp. R11 caused bleaching in novel field inoculation experiments, but infection and bleaching were moderated by algal defences. Exposure to excessive solar radiation indirectly increased algal susceptibility to bleaching by causing a precursor condition (‘fading’), which had depleted furanones. Association with shade-providing kelps prevented fading and bleaching in D. pulchra individuals. Bleaching had significant, sub-lethal perform

Background - In this study the efficacy of using marine macroalgae as a source for polyunsaturated fatty acids, which are associated with the prevention of inflammation, cardiovascular diseases and mental disorders, was investigated. Methods - The fatty acid (FA) composition in lipids from seven sea weed species from the North Sea (Ulva lactuca, Chondrus crispus, Laminaria hyperborea, Fucus serratus, Undaria pinnatifida, Palmaria palmata, Ascophyllum nodosum) and two from tropical seas (Caulerpa taxifolia, Sargassum natans) was determined using GCMS. Four independent replicates were taken from each seaweed species. Results - Omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs), were in the concentration range of 2-14 mg/g dry matter (DM), while total lipid content ranged from 7-45 mg/g DM. The n-9 FAs of the selected seaweeds accounted for 3%-56% of total FAs, n-6 FAs for 3%-32% and n-3 FAs for 8%-63%. Red and brown seaweeds contain arachidonic (C20:4, n-6) and/or eicosapentaenoic acids (EPA, C20:5, n-3), the latter being an important "fish" FA, as major PUFAs while in green seaweeds these values are low and mainly C16 FAs were found. A unique observation is the presence of another typical "fish" fatty acid, docosahexaenoic acid (DHA, C22:6, n-3) at ˜ 1 mg/g DM in S. natans. The n-6: n-3 ratio is in the range of 0.05-2.75 and in most cases below 1.0. Environmental effects on lipid-bound FA composition in seaweed species are discussed. Conclusion - Marine macroalgae form a good, durable and virtually inexhaustible source for polyunsaturated fatty acids with an (n-6) FA: (n-3) FA ratio of about 1.0. This ratio is recommended by the World Health Organization to be less than 10 in order to prevent inflammatory, cardiovascular and nervous system disorders. Some marine macroalgal species, like P. palmata, contain high proportions of the "fish fatty acid" eicosapentaenoic acid (EPA, C20:5, n-3), while in S. natans also docosahexaenoic acid (DHA, C22:6, n-3)

A two-dimensional biomarker approach, using stable isotopes ( 13C, 15N) and fatty acids, was used to evaluate differences both amongst and within benthic primary producer types (seagrass, fleshy red algae, calcareous red algae, brown algae, and seagrass periphyton) that are typical of the nearshore, temperate Australian region. The primary source of variance (as examined by permutational ANOVA) for all biomarkers examined was amongst primary producer types, as opposed to amongst species within type. 13C showed a clear separation (Monte Carlo p < 0.05) between seagrass (range of means =−10.1 to −14.0‰) and macroalgae (−14.6 to −25.2‰), but could not differentiate amongst the algal types examined. Similarly, distinct 15N signatures (p < 0.05) were found only for seagrass (range of means = 3.6–4.1‰) versus calcareous red algae (4.6–5.5‰), with all other types overlapping in their mean 15N values. In contrast, multivariate analysis of fatty acid data (using Canonical Analysis of Principal coordinates; CAP) distinguished not only between seagrass and macroalgae, but also between red and brown algae (and to a limited extent between the calcareous and fleshy red algal types). The principal unsaturated fatty acids in the samples were C20 polyunsaturates (found primarily in the macroalgae and periphyton), and C18 mono- and polyunsaturates, with high proportions of 18:2n-6 and 18:3n-3 typical of the seagrasses. The C18 monounsaturate 18:1n-7 was one of the most diagnostic compounds for the red algae examined, being present in very low amounts in seagrass and virtually absent in the brown algae. Conversely, brown algae were high in 18:4n-3, with 20:4n-3 particularly diagnostic of the kelp Ecklonia radiata. In contrast to stable isotopes, fatty acids helped distinguish different algal groups, thereby providing support that a two-dimensional approach using stable isotopes and fatty acids is likely to provide the most useful tool to distinguish primary producers in food web struc

In order to know the composition and distribution of macroalgae species in the lagoon complex of San Quintin Bay, Baja California, nine sampled were realized in three sites during 1988, 1989, 1990, 1995 and 1996; also a bibliographyc revision on the marine benthic algae cited from the study area. A total of 37 genera with 46 species of marine macroalgae were determined, of which 22 are Rhodophyta, (47.82 %), 12 Phaeophyta (26.08 %) and 12 Chlorophyta (26.08 %). The floristic list includes data on the presence and distribution of species found, reproductive stage, substrate and epiphytism. The families with best representation with regard to richness and occurrence are: Corallinaceae, Ceramiaceae, Rhodomelaceae (Rhodophyta); Ectocarpaceae, Scytosiphonaceae (Phaeophyta) and Ulvaceae (Chlorophyta). 18 (39.13 %) represent new records from the study area. Ulva expansa Linnaeus is reported for the first time for the occidental coast of Baja California. The floristc list and the bibliographyc information were actualized; the dates show that the number od species of marine algae from San Quintin Bay is composed for 59 species., RESUMEN Con la finalidad de determinar la distribución y composición de las especies de macroalgas presentes en el complejo lagunar de la bahía de San Quintín, Baja California, se realizaron nueve muestreos en tres sitios, durante 1988, 1989, 1990, 1995 y 1996; así como una revisión bibliográfica de algas marinas citadas para el área de estudio. Los resultados obtenidos del material recolectado indican la presencia de 37 géneros con 46 especies, de las cuales 22 son Rhodophyta (47.82 %), 12 Phaeophyta (26.08 %) y 12 Chlorophyta (26.08 %). En la lista florística se incluyen datos sobre la presencia y distribución de las especies en el área de estudio, su estado reproductivo, sustrato y epifitismo. En términos de diversidad de especies, las familias mejor representadas corresponden a Corallinaceae, Ceramiaceae, Rhodomelaceae (Rhodophyta), Ectocarpaceae, Scytosiphonaceae (Phaeophyta) y Ulvaceae (Chlorophyta). Del total de algas identificadas, 18 (39.13 %) representan nuevos registros para el área de estudio. Se cita por primera vez a Ulva expanda Linnaeus para la costa occidental de Baja California. Al depurar y actualizar la información bibliográfica desde el punto de vista florístico y nomenclatural, se encontró que la flora marina conocida hasta hoy para la bahía de San Quintín es de 59 especies.

[Abstrac] Five different brown seaweeds, Bifurcaria bifurcata, Saccorhiza polyschides, Ascophyllum nodosum, Laminaria ochroleuca and Pelvetia caniculata were studied for their ability to remove cadmium from aqueous solution. Kinetic of cadmium adsorption by all the algae was relatively fast, 90% of total adsorption occurring in less than one hour. These experiments could be accuracy described by a pseudo-second order rate equation, obtaining for the rate constant sorption, k, values between 1.66·10-3 and 9.92·10-3 g/mg·min. The equilibrium adsorption isotherms of Langmuir, Langmuir-Freundlich, Tóth and Freundlich were obtained for the quantitative description of the cadmium uptake. The maximum metal biosorption capacity (qmax) and the affinity constant (b) for all the algae were evaluated employing the Langmuir isotherm. The values for qmax were between 64 and 95 mg/g, whiles b was included between 0.036 and 0.094 L/mg. Moreover, a dimensionless constant separation factor, Rs, was calculated founding a favourable condition for the sorption system. 1 The effect of pH on biosorption was studied at values ranging from 1 to 6, demonstrating the importance of this parameter for the removal of cadmium. Equilibrium studies were carried out at pH 4.5. Acid-base properties of algae were studied by potentiometry, leading to pK values (from 3.54 to 3.98), which are comparable with typical values associated to the ionization of carboxyl groups of alginates. Furthermore, the total number of these acid groups was estimated.

[Abstract] The ability of Cystoseira baccata algal biomass to remove Hg(II) from aqueous solutions is investigated. The mercury biosorption process is studied through batch experiments at 25ºC with regard to the influence of contact time, initial mercury concentration, solution pH, salinity and presence of several divalent cations. The acid-base properties of the alga are also studied, since they are related to the affinity for heavy metals. The studies of the pH effect on the metal uptake evidence a sharp increasing sorption up to a pH value around 7.0, which can be ascribed to changes both in the inorganic Hg(II) speciation and in the dissociation state of the acid algal sites. The sorption isotherms at constant pH show uptake values as high as 178 mg.g-1 (at pH 4.5) and 329 mg.g-1 (at pH 6.0). The studies of the salinity influence on the Hg(II) sorption capacity of the alga exhibit two opposite effects depending on the electrolyte added; an increase in concentration of nitrate salts (NaNO3, KNO3) slightly enhances the metal uptake, on the contrary, the addition of NaCl salt leads to a drop in the sorption. The addition of different divalent cations to the mercury solution, namely Ca2+, Mg2+, Zn2+, Cd2+, Pb2+ and Cu2+, reveals that their effect on the uptake process is negligible. Finally, the equilibrium sorption results are compared with predictions 1 obtained from the application of a simple competitive chemical model, which involves a discrete proton binding constant and three additional constants for the binding of main neutral inorganic Hg(II) complexes, Hg(Cl) HgOHCl and Hg(OH)2, to the algal surface sites.

[Abstract] This work reports kinetic and equilibrium studies of cadmium(II) and lead(II) adsorption by the brown seaweed Cystoseira baccata. Kinetic experiments demonstrated rapid metal uptake. Kinetic data were satisfactorily described by a pseudo-second order chemical sorption process. Temperature change from 15 to 45 ºC showed small variation on kinetic parameters. Langmuir-Freundlich equation was selected to describe the metal isotherms and the proton binding in acid-base titrations. The maximum metal uptake values were around 0.9 mmol•g-1 (101 and 186 mg•g-1 for cadmium(II) and lead(II), respectively) at pH 4.5 (raw biomass), while the number of weak acid groups were 2.2 mmol•g-1 and their proton binding constant, KH, 103.67 (protonated biomass). FTIR analysis confirmed the participation of carboxyl groups in metal uptake. The metal sorption was found to increase with the solution pH reaching a plateau above pH 4. Calcium and sodium nitrate salts in solution were found to affect considerably the metal biosorption.

Mineral content was determined in several brown (Fucus vesiculosus, Laminaria digitata, Undaria pinnatifida) and red (Chondrus crispus, Porphyra tenera) edible marine sea vegetables. Seaweeds contained high proportions of ash (21.1–39.3%) and sulphate (1.3–5.9%). In brown algae, ash content (30.1–39.3%) was higher than in red algae (20.6–21.1%). Atomic absorption spectrophotometry of the ashes indicated that marine seaweeds contained higher amounts of both macrominerals (8.083–17,875 mg/100g; Na, K, Ca, Mg) and trace elements (5.1–15.2 mg/100 g; Fe, Zn, Mn, Cu), than those reported for edible land plants. Edible brown and red seaweeds could be used as a food supplement to help meet the recommended daily intake of some essential minerals and trace elements.