, A Novel Cosmopolitan Species of Blue Diatoms.

Specimens of a new species of blue diatoms from the genus Simonsen were discovered in geographically distant sampling sites, first in the Canary Archipelago, then North Carolina, Gulf of Naples, the Croatian South Adriatic Sea, and Turkish coast of the Eastern Mediterranean Sea. An exhaustive characterization of these specimens, using a combined morphological and genomic approach led to the conclusion that they belong to a single new to science cosmopolitan species, sp. nov.

Extraction and Purification of R-phycoerythrin from Marine Red Algae.

This chapter focuses on the recovery of an R-Phycoerythrin (R-PE)-enriched fraction from marine algae. Since R-PE is a proteinaceous pigment, we have developed a simple and rapid two-step method devoted to the extraction and purification of R-PE from marine red algae. Here we describe a phosphate buffer extraction followed by anion exchange chromatography carried on a DEAE Sepharose Fast Flow column.

One-step purification of R-phycoerythrin from the red edible seaweed Grateloupia turuturu.

A one-step chromatographic method for the purification of R-phycoerythrin (R-PE) of Grateloupia turuturu Yamada is described. Native R-PE was obtained with a purity index of 2.89 and a recovery yield of 27% using DEAE-Sepharose Fast Flow chromatography with a three-step increase in ionic strength.

Marennine, promising blue pigments from a widespread Haslea diatom species complex.

In diatoms, the main photosynthetic pigments are chlorophylls a and c, fucoxanthin, diadinoxanthin and diatoxanthin. The marine pennate diatom Haslea ostrearia has long been known for producing, in addition to these generic pigments, a water-soluble blue pigment, marennine. This pigment, responsible for the greening of oysters in western France, presents different biological activities: allelopathic, antioxidant, antibacterial, antiviral, and growth-inhibiting.

Physicochemical factors affecting the stability of two pigments: R-phycoerythrin of Grateloupia turuturu and B-phycoerythrin of Porphyridium cruentum.

Phycoerythrin is a major light-harvesting pigment of red algae, which could be used as a natural dye in foods. The stability of R-phycoerythrin of Grateloupia turuturu and B-phycoerythrin of Porphyridium cruentum in relation to different light exposure times, pHs, and temperatures was studied. Regarding the light exposure time, after 48h, the reduction in concentrations of B-phycoerythrin and R-phycoerythrin were 30±2.

Optimization of hydrolysis conditions of Palmaria palmata to enhance R-phycoerythrin extraction.

In this study, response surface methodology was applied to optimize R-phycoerythrin extraction from the red seaweed Palmaria palmata, using enzymatic digestion. Several algal treatments prior to digestion were first investigated. The extraction yield and the purity index of R-phycoerythrin, and the recovery of proteins and reducing sugars in the water-soluble fraction were then studied in relation to the hydrolysis time, the temperature and the enzyme/seaweed ratio.

A (2)H solid-state NMR study of the effect of antimicrobial agents on intact Escherichia coli without mutating.

Solid-state nuclear magnetic resonance (NMR) is a useful tool to probe the organization and dynamics of phospholipids in bilayers. The interactions of molecules with membranes are usually studied with model systems; however, the complex composition of biological membranes motivates such investigations on intact cells. We have thus developed a protocol to deuterate membrane phospholipids in Escherichia coli without mutating to facilitate (2)H solid-state NMR studies on intact bacteria.

Biological activities of purified marennine, the blue pigment responsible for the greening of oysters.

Marennine, the blue pigment produced by the diatom Haslea ostrearia , exists in two different forms, the intra- and extracellular forms. We investigated the antibacterial, antiviral, and antiproliferative properties of both of these forms. Both forms of marennine inhibited the development of marine bacteria, in particular the pathogenic organism Vibrio aesturianus , at concentrations as low as 1 μg/mL, but they did not display any effect on a wide range of pathogenic bacteria that are relevant for food safety.

Antioxidant and free radical scavenging properties of marennine, a blue-green polyphenolic pigment from the diatom Haslea ostrearia (Gaillon/Bory) Simonsen responsible for the natural greening of cultured oysters.

Among microalgae, the marine diatom Haslea ostrearia has the distinctive feature of synthesizing and releasing, into the surrounding environment, a blue-green polyphenolic pigment called marennine. The oyster-breeding industry commonly makes use of this natural phenomenon for the greening of oysters grown in the ponds of the French Atlantic coast. This article reports the in vitro antioxidant properties of pure marennine.