Immunomodulatory and Antioxidant Activities of Sulfated Polysaccharides from Laminaria ochroleuca, Porphyra umbilicalis, and Gelidium corneum.

Seaweeds of the genera Laminaria, Gelidium, and Porphyra have been used in both food and non-food industries due to their unique properties and characteristic biological activity. This study assesses the antioxidant activity and immunomodulatory properties of the acidic polysaccharides extracted from Laminaria ochroleuca, Porphyra umbilicalis, and Gelidium corneum collected in the Atlantic coast of Tarifa (Cadiz, Spain). The proliferation of murine cell line RAW 264 decreased with increasing concentration of polysaccharides of the three algal species. The highest both antioxidant (25.69 µmol TE g-1 DW) and immunomodulatory activities were observed in the sulfated polysaccharides of L. ochroleuca compared to that of P. umbilicalis and G. corneum. Sulfated polysaccharides of L. ochroleuca presented high potential anticancer activity in cell lines of human colon cancer HTC-116 (IC50 = 0.44 mg mL-1), human malignant melanoma G-361 (IC50 = 5.42 mg mL-1), breast adenocarcinoma human MCF-7 (IC50 = 8.32 mg mL-1), and human leukemia U-937 (IC50 = 3.72 mg mL-1). It is concluded that metabolites of L. ochroleuca can offer significant advantages for the pharmaceutical industry, particularly when macrophage activation is required.

Relevance of mytilid shell microtopographies for fouling defence--a global comparison.

Prevention of epibiosis is of vital importance for most aquatic organisms, which can have consequences for their ability to invade new areas. Surface microtopography of the shell periostracum has been shown to have antifouling properties for mytilid mussels, and the topography shows regional differences. This article examines whether an optimal shell design exists and evaluates the degree to which shell microstructure is matched with the properties of the local fouling community. Biomimics of four mytilid species from different regional provenances were exposed at eight different sites in both northern and southern hemispheres. Tendencies of the microtopography to both inhibit and facilitate fouling were detected after 3 and 6 weeks of immersion. However, on a global scale, all microtopographies failed to prevent fouling in a consistent manner when exposed to various fouling communities and when decoupled from other shell properties. It is therefore suggested that the recently discovered chemical anti-microfouling properties of the periostracum complement the anti-macrofouling defence offered by shell microtopography.

Applications of cyanobacteria in biotechnology.

Cyanobacteria have gained a lot of attention in recent years because of their potential applications in biotechnology. We present an overview of the literature describing the uses of cyanobacteria in industry and services sectors and provide an outlook on the challenges and future prospects of the field of cyanobacterial biotechnology. Cyanobacteria have been identified as a rich source of biologically active compounds with antiviral, antibacterial, antifungal and anticancer activities. Several strains of cyanobacteria were found to accumulate polyhydroxyalkanoates, which can be used as a substitute for nonbiodegradable petrochemical-based plastics. Recent studies showed that oil-polluted sites are rich in cyanobacterial consortia capable of degrading oil components. Cyanobacteria within these consortia facilitated the degradation processes by providing the associated oil-degrading bacteria with the necessary oxygen, organics and fixed nitrogen. Cyanobacterial hydrogen has been considered as a very promising source of alternative energy, and has now been made commercially available. In addition to these applications, cyanobacteria are also used in aquaculture, wastewater treatment, food, fertilizers, production of secondary metabolites including exopolysaccharides, vitamins, toxins, enzymes and pharmaceuticals. Future research should focus on isolating new cyanobacterial strains producing high value products and genetically modifying existing strains to ensure maximum production of the desired products. Metagenomic libraries should be constructed to discover new functional genes that are involved in the biosynthesis of biotechnological relevant compounds. Large-scale industrial production of the cyanobacterial products requires optimization of incubation conditions and fermenter designs in order to increase productivity.

Marine biofilms as mediators of colonization by marine macroorganisms: implications for antifouling and aquaculture.

In the marine environment, biofilms on submerged surfaces can promote or discourage the settlement of invertebrate larvae and macroalgal spores. The settlement-mediating effects of biofilms are believed to involve a variety of biofilm attributes including surface chemistry, micro-topography, and a wide range of microbial products from small-molecule metabolites to high-molecular weight extracellular polymers. The settled organisms in turn can modify microbial species composition of biofilms and thus change the biofilm properties and dynamics. A better understanding of biofilm dynamics and chemical signals released and/or stored by biofilms will facilitate the development of antifouling and mariculture technologies. This review provides a brief account of 1) existing knowledge of marine biofilms that are relevant to settlement mediation, 2) biotechnological application of biofilms with respect to developing non-toxic antifouling technologies and improving the operation of aquaculture facilities, and 3) challenges and future directions for advancing our understanding of settlement-mediating functions of biofilms and for applying this knowledge to real-life situations.

Electrospray mass spectrometric study of melittin trypsinolysis by a kinetic approach.

The kinetics of tryptic digestion of melittin was studied by combined electrospray ionization time-of-flight mass spectrometry and high-performance liquid chromatography. The ratios of the kinetic constants for cleavage of the peptide bonds that are susceptible to trypsin action were determined. It is shown that trypsin does not manifest affinity for the hydrolysis of the peptide bonds inside the Arg,Lys cluster series as efficiently as it cleaves the peptide at the separately localized Lys residue. This feature demonstrates clearly the advantage of the kinetic approach to tryptic mapping of proteins. The kinetic approach allows the determination of not only discrete structural segments in protein structure but also their relative locations and their amino acid sequences. Using the melittin digests and some artificially prepared amino acids and dipeptides mixtures as models, it is shown that the presence and nature of basic amino acids predetermines the charge states of the molecules analyzed by electrospray but not the yields of their ions. The aliphatic parts of the molecules seem to be more important in determining the actual ion yields.