Electrochromic Properties and Electrochemical Behavior of Marennine, a Bioactive Blue-Green Pigment Produced by the Marine Diatom Haslea ostrearia.

Marennine has long been known as the unique peculiar pigment responsible for the natural greening of oysters. It is specifically produced by the marine diatom Haslea ostrearia and it is a natural blue molecule indeed promising for food industry because of the rarity of such non-toxic, blue-colored pigments. In the search for its still not defined molecular structure, investigation of the color changes with the redox state has been carried out combining different approaches. Reducing and oxidizing chemicals have been added to purified marennine solutions and a stable blue-green color has been confirmed for the oxidized state, while a yellow color corresponded to the reduced unstable state. Raman spectroscopy has been used to monitor changes in the Raman spectra corresponding to the different colored states, and cyclic voltammetry has allowed the detection of a redox system in which protons and electrons are exchanged. These findings show that marennine is a suitable stable blue pigment for use in food applications and help in the elucidation of the chromophore structure.

Extraction Improvement of the Bioactive Blue-Green Pigment "Marennine" from Diatom Haslea ostrearia's Blue Water: A Solid-Phase Method Based on Graphitic Matrices.

The compound "marennine" is a blue-green pigment produced by the benthic microalgae Haslea ostrearia, with pathogenicity reduction activities against some bacteria and promising potential as a natural pigment in seafood industries. After decades of research, the chemical family of this compound still remains unclear, mainly because structural studies were impaired by the presence of co-extracted compounds in marennine isolates. To improve the purity of marennine extract, we developed a novel extraction method using a graphitic stationary phase, which provides various advantages over the previous procedure using tandem ultrafiltration. Our method is faster, more versatile, provides a better crude yield (66%, compared to 57% for ultrafiltration) and is amenable to upscaling with continuous photobioreactor cultivation. Our goal was to take advantage of the modulable surface properties of the graphitic matrix by optimizing its interactions with marennine. As such, the effects of organic modifiers, pH and reducing agents were studied. With this improvement on marennine purification, we achieved altogether the isolation of a fucoidan-related, sulfated polysaccharide from blue water. Characterization of the polysaccharides fraction suggests that roughly half of UV-absorbing compounds could be isolated from the marennine crude extracts. The identification of sulfated polysaccharides could be a major breakthrough for marennine purification, providing targeted isolation techniques. Likewise, the added value of Haslea ostrearia and the role of polysaccharides in previous marennine chemical characterization and bioactivity studies remain to be determined.

United States response to the COVID-19 pandemic, January-November 2020.

As of November 2020, the United States leads the world in confirmed coronavirus disease 2019 (COVID-19) cases and deaths. Over the past 10 months, the United States has experienced three peaks in new cases, with the most recent spike in November setting new records. Inaction and the lack of a scientifically informed, unified response have contributed to the sustained spread of COVID-19 in the United States. This paper describes major events and findings from the domestic response to COVID-19 from January to November 2020, including on preventing transmission, COVID-19 testing and contact tracing, ensuring sufficient physical infrastructure and healthcare workforce, paying for services, and governance. We further reflect on the public health response to-date and analyse the link between key policy decisions (e.g. closing, reopening) and COVID-19 cases in three states that are representative of the broader regions that have experienced spikes in cases. Finally, as we approach the winter months and undergo a change in national leadership, we highlight some considerations for the ongoing COVID-19 response and the broader United States healthcare system. These findings describe why the United States has failed to contain COVID-19 effectively to-date and can serve as a reference in the continued response to COVID-19 and future pandemics.