Pennsylvanian phylloid algae interpreted as shallow-water xenophyophores

Xenophyophores, a group of agglutinated rhizopod protists, occur in nearly all the world's oceans at depths generally in excess of 1OOO m. In certain areas they dominate deep-sea, megafaunal communities. Their widespread distribution indicates a well-established adaptive radiation. Only one fossil analogue, however, has been proposed. This is Paleodictyon , a trace fossil that superficially resembles the Recent infaunal xenophyophore Occultammina profunda in morphology. The platy xenophyophore genus Psammina closely resembles certain late Palaeozoic fossils from northeastern Kansas that have been referred to as 'phylloid algae'. Here we compare modern xenophyophore structure with that of the fossil phylloids. By reconstructing the fossils, analysing their thin sections with polarized, blue, and ultraviolet light and subjecting them to Q-switched laser ablation, we conclude that certain phylloids could represent shallow-water xenophyophores. *** Phylloid algae, xenophyophores, motphology, reconstruction, laser ablation, Pennsylvanian.     

Pharmaceuticals from cultured algae

Summary An algae screening program, including cultured macroalgae, cultured cyanobacteria and cultured eukaryotic microalgae has been undertaken. Methods for the isolation, purification, preservation and cultivation of axenic cyanobacteria and eukaryotic cultures have been developed. Screening of these groups for biologically active components has lead to the isolation of pachydictyol and caulerpenyne from cultured macroalgae, while a series of hapalindoles and an antifungal depsipeptide have been isolated from cyanobacteria.     

Ultrahigh bioproductivity from algae

The potential for dramatic increases in bioproductivity in algal photobioreactors relative to current biomass approaches, e.g., for converting sunlight into biofuels, by an unorthodox integration of photonics and biotechnologies is described. The key to greater biomass yields—projected as high as 100 g dry weight m⁻² h⁻¹—is a pronounced heightening of algal flux tolerance, achieved by tailoring the photonic temporal, spectral and intensity characteristics with pulsed light-emitting diodes. Such tailored photonic input is applied in concert with thin-channel ultradense culture photobioreactors with flow patterns that produce rapid light/dark algae exposure cycles. The artificial-light scheme is globally feasible only with electricity generated from renewables. Recent advances in ultra-efficient concentrator photovoltaics, as well as high-performance light-emitting diodes, create a practical reality for converting sunlight into pulsed red light and delivering it to indoor photobioreactors, with characteristic pulse times and intensities optimally suited to the rate-limiting dark reactions of photosynthesis. Cellular engineering built upon recent progress in modifying algal chlorophyll antenna size, in combination with metabolic engineering, could further enhance bioproductivity. The proposed strategy requires no major advances for implementation and adopts existing technologies. Revision submitted to Applied Microbiology and Biotechnology on 25 June 2007.     

Glutamate agonists from marine algae

The occurrence of three glutamate agonists — glutamic acid, D-homocysteic acid and kainic acid — in a spontaneous mutant of Palmaria palmata is reported. Glutamic acid and D-homocysteic acid, but not kainic acid, were found in the wild-type plant. The closely related glutamate agonist, domoic acid, was found in the red alga Chondria baileyana and in the diatom Nitzschia pungens forma multiseries. In the diatom, domoic acid can build up to high levels in excess of 3% (dry wt.), making N. pungens a potential commercial source of this neuroactive amino acid. Information is also presented on the distribution, chemistry and biological activity of neuroactive amino acids from algae, and a possible biogenic relationship among kainoid metabolites is discussed. author for correspondence     

Effects of nitrogen stressed algae on different Acartia species

We studied the reproductive response of two copepod species,Acartia tonsa and Acartia clausii, fed algae with differentC:N ratios (4.5 and 9.1 molar ratios respectively) in orderto investigate the influence of nutritional imbalances on calanoidcopepods egg production. Adult females were incubated with thecryptophyte Rhodomonas sp. at saturating concentrations. Thealgae were cultured under nitrogen depleted and sufficient conditions.Ingestion rates of the animals fed with different algae andtheir response in terms of egg production and hatching successof the eggs were quantified. Both species produced more eggwhen fed with nitrogen-limited algae. Ingestion rates and egghatching differed between species, but were not significantlyaffected by the quality of the food. The only difference betweenthe two species in their reaction to food quality was that A.tonsa increased the number of resting eggs, whereas no restingegg production was observed in A. clausii when fed with nitrogenlimited algae. These results support the recent suggestion thata moderately high prey C:N ratio (10–15) supports a higheregg production than a C:N ratio substantially <10.     

Fossil woods from the Late Cretaceous Aachen Formation

Silicified fossil woods from the Late Cretaceous (Santonian) Aachen Formation of northeast Belgium, southernmost Netherlands and adjacent Germany were investigated. Gymnosperms dominate this assemblage: Taxodioxylon gypsaceum, T. cf. gypsaceum, T. cf. albertense (all Taxodiaceae), Dammaroxylon aachenense sp. nov. (Araucariaceae), Pinuxylon sp. (Pinaceae), and Scalaroxylon sp. (Cycad or Cycadeoid). Angiosperms are minor constituents: Nyssoxylon sp. (Nyssaceae?, Cornaceae?), Mastixioxylon symplocoides sp. nov. (Mastixiaceae?, Symplocaceae?), Plataninium decipiens (Platanaceae) and Paraphyllanthoxylon cf. marylandense (Anacardiaceae?, Burseraceae?, Lauraceae?).The composition of this assemblage and the anatomy of the woods indicate a seasonal and humid warm-temperate to subtropical climate.     

Antioxidant properties of a new antioxidative peptide from algae protein waste hydrolysate in different oxidation systems

Microalgae have been a popular edible food, but there are no known reports on the antioxidative peptides derived from microalgae. The algae protein waste, which is normally discarded as animal feed, is a by-product during production of algae essence from microalgae, Chlorella vulgaris. Algae protein waste was hydrolyzed using pepsin, and a potent antioxidative peptide of VECYGPNRPQF was separated and isolated. The peptide could efficiently quench a variety of free radicals, including hydroxyl radical, superoxide radical, peroxyl radical, DPPH radical and ABTS radicals, and performed more efficiently than that observed for BHT, Trolox and peptides from marine protein sources in most cases. The purified peptide also has significant protective effects on DNA and prevents cellular damage caused by hydroxyl radicals. In addition, the peptide has gastrointestinal enzyme-resistance and no cytotoxicity observed in human lung fibroblasts cell lines (WI-38) in vitro. These results demonstrate that inexpensive algae protein waste could be a new alternative to produce antioxidative peptides.     

Bioactive natural products from blue-green algae

Since 1981 we have cultured and prepared lipophilic and hydrophilic extracts from more than 1500 strains representing some 400 species of blue-green algae. Screening for a wide variety of potentially useful bioactivities, including cytotoxic, multi-drug-resistance reversal, antifungal, and antiviral effects, has led to the discovery and identification of numerous novel bioactive metabolites including peptides, macrolides and glycosides.A systematic evaluation of the chemical and environmental factors that influence the production of secondary metabolites inScytonema ocellatum, which produces tolytoxin (a macrocyclic lactone that depolymerizes actinin vivo to disrupt cell division in eukaryotic organisms), has shown that cyanophytes can be manipulated in culture to improve growth and product yields.     

Metabolites from algae with economical impact

In order to survive in a highly competitive environment, freshwater or marine algae have to develop defense strategies that result in a tremendous diversity of compounds from different metabolic pathways. Recent trends in drug research from natural sources have shown that algae are promising organisms to furnish novel biochemically active compounds. The current review describes the main substances biosynthesized by algae with potential economic impact in food science, pharmaceutical industry and public health. Emphasis is given to fatty acids, steroids, carotenoids, polysaccharides, lectins, mycosporine-like amino acids, halogenated compounds, polyketides and toxins.     

Nonhalogenated organic molecules from Laurencia algae

The marine red algae of the genus Laurencia have produced more 700 secondary metabolites and exhibited high molecular diversity and intriguing bioactivity. Since the halogenated structures have been comprehensively reviewed previously, this review, covering up to the end of 2012, mainly focuses on the source, structure elucidation, and bioactivity of nonhalogenated organic molecules from Laurencia spp. as well as the relationship between nonhalogenated and halogenated products. Overall, 173 new or new naturally occurring compounds with 58 skeletons, mainly including sesquiterpenes, diterpenes, triterpenes, and C₁₅-acetogenins, are described.     

Antiviral carbohydrates from marine red algae

The solubility of the O₂ in the Dead Sea brine was determined over the temperature range 5 °C–50 °C using a modified Winkler titration, volumetric analysis, and a polarographic sensor. The solubility at room temperature and 1 atmosphere pressure was ca. 1 mg l^–1, and the temperature coefficient 0.006 mg 1^–1° C^–1 . The data are nearly consistent with sea water solubility extrapolated to Dead Sea brine salinity.     

Screening of different algae for green synthesis of gold nanoparticles

The cyanobacteria Phormidium valderianum, P. tenue and Microcoleus chthonoplastes and the green algae Rhizoclonium fontinale, Ulva intestinalis, Chara zeylanica and Pithophora oedogoniana were exposed to hydrogen tetrachloroaurate solution and were screened for their suitability for producing nano‐gold. All three cyanobacteria genera and two of the green algae (Rhizoclonium fontinale and Ulva intestinalis) produced gold nanoparticles intracellularly, confirmed by purple colouration of the thallus within 72?h of treatment at 20°C. Extracted nanoparticle solutions were examined by UV‐vis spectroscopy, transmission electron microscopy (TEM) and X‐ray diffractometry (XRD). XRD confirmed the reduction of Au (III) to Au (0). UV‐vis spectroscopy and TEM studies indicated the production of nanoparticles having different shapes and sizes. Phormidium valderianum synthesized mostly spherical nanoparticles, along with hexagonal and triangular nanoparticles, at basic and neutral pHs (pH 9 and pH 7, respectively). Medicinally important gold nanorods were synthesized (together with gold nanospheres) only by P. valderianum at acidic pH (pH 5); this was initially determined by two surface plasmon bands in UV‐vis spectroscopy and later confirmed by TEM. Spherical to somewhat irregular particles were produced by P. tenue and Ulva intestinalis (TEM studies). The UV‐vis spectroscopy of the supernatant of other algal extracts indicated the formation of mostly spherical particles. Production of gold nanoparticles by algae is more ecofriendly than purely chemical synthesis. However, the choice of algae is important: Chara zeylanica and Pithophora oedogoniana were found to be unable to produce nanoparticles.     

Two interesting algae from Czech reservoirs

Paulschulzia pseudovolvox (Schulz)Skuja, a member of theTetrasporales, is recorded for the first time for Czechoslovakia.Amphidinium radiatum Javorn., a member of theGymnodiniales is recognized. Further information about its variability is supplemented. The algae were studied in two reservoirs.