Antifouling Activity of Halogenated Compounds Derived from the Red Alga Sphaerococcus coronopifolius: Potential for the Development of Environmentally Friendly Solutions

Nowadays, biofouling is responsible for enormous economic losses in the maritime sector, and its treatment with conventional antifouling paints is causing significant problems to the environment. Biomimetism and green chemistry approaches are very promising research strategies for the discovery of new antifouling compounds. This study focused on the red alga Sphaerococcus coronopifolius, which is known as a producer of bioactive secondary metabolites. Fifteen compounds, including bromosphaerol (1), were tested against key marine biofoulers (five marine bacteria and three microalgae) and two enzymes associated with the adhesion process in macroalgae and invertebrates. Each metabolite presented antifouling activity against at least one organism/enzyme. This investigation also revealed that two compounds, sphaerococcinol A (4) and 14R-hydroxy-13,14-dihydro-sphaerococcinol A (5), were the most potent compounds without toxicity towards oyster larvae used as non-target organisms. These compounds are of high potential as they are active towards key biofoulers and could be produced by a cultivable alga, a fact that is important from the green chemistry point of view.     

Fusarium wilt of watermelon in Cyprus and its management with soil solarization combined with fumigation or ammonium fertilizers

Fusarium wilt is a limiting factor to watermelon production in Cyprus. In previous studies, soil solarization applied in 1-m-wide strips provided only partial disease control. In order to improve the effectiveness of solarization, three field experiments were carried out in heavily infested soils, using various solarization techniques, alone or in combination with methyl bromide fumigation or soil amendments with ammonium-based fertilizers. Increasing the width of the solarization strip from 1 to 2 m had no significant influence on its effectiveness. Solarization with a double rather than single polyethylene sheet, in either 1- or 2-m-wide strips, improved slightly the level of wilt control but had no significant effect on yield. Combined solarization–methyl bromide treatments, however, improved significantly the level of wilt control and increased marketable yield by up to 100% over that obtained with either method alone. The low rate of methyl bromide (50gm⁻²) was as effective as the normal rate used by growers (100 g m⁻). Soil amendment with ammonium-based fertilizers improved even more the effectiveness of solarization and increased yield by up to 200% over that obtained with solarization alone. Best results were obtained with ammonium sulphate or monoammonium phosphate at a rate equivalent to 180 kg N ha⁻¹.     

Colonization Patterns and Densities of Zebra Mussel Dreissena in Muddy Offshore Sediments of Western Lake Erie, Canada

Zebra mussels (Dreissena) have expanded rapidly throughout most of the Laurentian Great Lakes since their inadvertent release in 1986. These exotic molluscs now occur in great numbers on the bottom of western Lake Erie where they are found increasingly in deeper areas of the basin (average depth: 10 m), on soft, muddy substrates. This study is aimed at quantifying the density and the distribution patterns of mussel colonization in the basin as a first step in investigating the effect on sediment properties of such an abrupt change in benthic community structure. Underwater video imagery and diver-collected samples taken from representative o shore areas (seven sites) in western Lake Erie showed colonization levels of up to 20,000 live mussels per m² in soft sediments (adults with shells >10 mm comprised 47%). Digital side-scan sonar records confirmed that colonization patterns were not random, but showed distinctive spatial signatures ranging from 30-m-long parallel stripes, to large ovate masses. Broad irregular mats were found in association with hard bottoms (bedrock, boulders, or wrecks and large debris). Mussel densities were averaged from the sites, assuming consistent relationships with substrate type and were combined with digitized percentage of areal coverage of major bottom types in western Lake Eric. This resulted in the first population figure of 10¹³ in the basin. This figure includes molluscs ofall sizes > 0.84 mm.     

In vitro metabolism of etrimfos by rat and mouse liver

The in vitro metabolism of etrimfos, O,O-dimethyl-O-(2-ethyl-4-ethoxy-6-pyrimidinyl) phosphorothionate, was studied in rat and mouse liver. The major route of metabolism in rat and mouse liver was via glutathione transferase, and the predominant metabolite was desmethyl etrimfos. The higher toxicity of etrimfos to mice was attributed mainly to lower amounts of reduced glutathione in mouse liver. Thus, the level of reduced glutathione appears to be in part responsible for the selective toxicity. No oxygen analog of etrimfos was found.     

Marine Biopolymers as Bioactive Functional Ingredients of Electrospun Nanofibrous Scaffolds for Biomedical Applications

Marine biopolymers, abundantly present in seaweeds and marine animals, feature diverse structures and functionalities, and possess a wide range of beneficial biological activities. Characterized by high biocompatibility and biodegradability, as well as unique physicochemical properties, marine biopolymers are attracting a constantly increasing interest for the development of advanced systems for applications in the biomedical field. The development of electrospinning offers an innovative technological platform for the production of nonwoven nanofibrous scaffolds with increased surface area, high encapsulation efficacy, intrinsic interconnectivity, and structural analogy to the natural extracellular matrix. Marine biopolymer-based electrospun nanofibrous scaffolds with multifunctional characteristics and tunable mechanical properties now attract significant attention for biomedical applications, such as tissue engineering, drug delivery, and wound healing. The present review, covering the literature up to the end of 2021, highlights the advancements in the development of marine biopolymer-based electrospun nanofibers for their utilization as cell proliferation scaffolds, bioadhesives, release modifiers, and wound dressings.