Covering: up to the end of 2010 β-Glucans is the common name given to a group of chemically heterogeneous polysaccharides. They are long- or short-chain polymers of (1→3)-β-linked glucose moieties which may be branched, with the branching chains linked to the backbone by a (1→6)-β linkage. β-(1,3)-Glucans are widely distributed in bacteria, algae, fungi and plants, where they are involved in cell wall structure and other biological function. β-Glucans have been shown to provide a remarkable range of health benefits, and are especially important against the two most common conventional causes of death in industrialized countries, i.e. cardiovascular diseases (where they promote healthy cholesterol and blood glucose levels) and cancer (where they enhance immune system functions). This Highlight provides a comprehensive and up-to-date commentary on β-glucans, their chemistry, physico-chemistry, functional role in immunological responses, and possible applications as therapeutic tools. In addition, we discuss the mechanism behind their health benefits, which are not yet fully understood.

The aim of this study was to verify the activation details and products of human lymphomonocytes, stimulated by different β‐glucans, that is Euglena paramylon, MacroGard^®, and lipopolysaccharide. We investigated the gene expression of inflammation‐related cytokines and mediators, transactivation of relevant transcription factors, and phagocytosis role in cell‐glucan interactions, by means of RT‐PCR, immunocytochemistry, and colorimetric assay. Our results show that sonicated and alkalized paramylon upregulates pro‐inflammatory factors (NO, TNF‐α, IL‐6, and COX‐2) in lymphomonocytes. A clear demonstration of this upregulation is the increased transactivation of NF‐kB visualized by immunofluorescence microscopy. Phagocytosis assay showed that internalization is not a mandatory step for signaling cascade to be triggered, since immune activity is not present in the lymphomonocytes that have internalized paramylon granules and particulate MacroGard^®. Moreover, the response of Euglena β‐glucan‐activated lymphomonocytes is much greater than that induced by commercially used β‐glucans such as MacroGard^®. Our in vitro results indicate that linear fibrous Euglena β‐glucan, obtained by sonication and alkaline treatment can act as safe and effective coadjutant of the innate immune system response.

β-glucans, heterogeneous glucose polymers present in many organisms, have the capability to activate the innate immune system. Efficacy of activation depends on purity of the compound, molecular structure, polymerization degree, and source. One of the purest forms of crystallized β-(1–3)-glucan present in nature is the paramylon extracted from the WZSL non-chloroplastic mutant of Euglena gracilis, which can be processed to produce linear nanofibers capable of interacting with specific receptors present on cell membranes. The effects of these nanofibers, already investigated on plants, animals, and humans, will be analyzed.

This review reports state-of-the-art methods for automated microalgae classification aimed at monitoring water ecosystem conditions by means of digital microscopy, its current state and indications of future directions the field is expected to take.

Many algae synthesize compounds that have exceptional properties of nutraceutical, pharmacological, and biomedical interest. Pigments, fatty acids, phenols, and polysaccharides are among the main compounds investigated so far. Polysaccharides are the most exploited compounds, widely used in pharmaceutical, food, and chemical industries, which are at present entering into more advanced applications by gaining importance, from a therapeutic point of view, as antioxidant, antimicrobial, antitumor, and immunomodulatory agents. Establishing algae as an alternative supplement would complement the sustainable and environmental requirements in the framework of human health and well-being. This review focuses on the proprieties and uses of the main micro- and macroalgae metabolites, describing their potential for application in the different industrial sectors, from food/feed to chemical and pharmacological. Further, current technologies involved in bioactive molecule extraction strategies are documented.

In microorganisms and plants, chromium (Cr) is not essential for any metabolic process, and can ultimately prove highly deleterious. Due to its widespread industrial use, chromium has become a serious pollutant in diverse environmental settings. The presence of Cr leads to the selection of specific algal populations able to tolerate high levels of Cr compounds. The varying Cr-resistance mechanisms displayed by microorganisms include biosorption, diminished accumulation, precipitation, reduction of Cr⁶⁺ to Cr³⁺, and chromate efflux. In this paper we describe the effects of Cr⁶⁺ (the most toxic species) on the photosynthetic and photoreceptive apparatus of two fresh water microalgae, Eudorina unicocca and Chlorella kessleri. We measured the effect of this heavy metal by means of in vivo absorption microspectroscopy of both the thylakoid compartments and the eyespot. The decomposition of the overall absorption spectra in pigment constituents indicates that Cr⁶⁺ effects are very different in the two algae. In E. unicocca the metal induced a complete pheophinitization of the chlorophylls and a modification of the carotenoids present in the eyespot after only 120 h of exposition at a concentration equal or greater than 40 µM, which is the limit for total Cr discharge established by US EPA regulations. In C. kessleri, chromium concentrations a hundred times higher than this limit had no effect on the photosynthetic machinery. The different tolerance level of the two algae is suggested to be due to the different properties of the mucilaginous envelope and cell wall covering, respectively, the colonies of Eudorina and the single cells of Chlorella, which binds chromium cations to a different extent.