Subject: Life Sciences, Microbiology Keywords: Arthrospira platensis; Spirulina; boosting effect; impedance analysis; commercial starter cultures; SLAB; rheological analysis
Online: 15 December 2019 (14:43:49 CET)
Arthrospira platensis, commercially known as Spirulina, is a fresh-water cyanobacterium that is gaining even more attention in the last years due to its high biological and nutritional value. For this reason, it has been employed in several food applications, to obtain or enhance functional and technological properties of cheese, yogurt, bread, cookies or pasta. The aim of this work was to evaluate the potential boosting effect of two different concentrations (0.25% and 0.50%) of Arthrospira platensis on the fermentation capability of several starter LAB strains, 1 probiotic and 4 commercial mix culture. These strains were used to ferment three different substrates and their fermentation behaviors were evaluated by impedance analyses together with rheological and color measurements. It was demonstrated that the booster effect took place, but it was variable and dependent not only on the strain or mix culture used, but also on the substrate and Arthrospira platensis concentration. Also, rheological and color modifications were found to be dependent of these factors.
ARTICLE | doi:10.20944/preprints201811.0283.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: Arthrospira maxima; antioxidant; cardiovascular; nutraceutical; systolic blood pressure
Online: 12 November 2018 (10:42:25 CET)
1) Background: Spirulina (Arthrospira) maxima has shown beneficial effects such anti-dyslipidemic, antiviral, antioxidant and antihypertensive. However, there are few and limited clinical studies. 2) Methods: a prospective, randomized, parallel pilot study of 4.5 g administration of Spirulina maxima or placebo for 12 weeks in 16 patients with systemic arterial hypertension undergoing treatment with ACE inhibitors was performed to assess the effects on endothelial damage and oxidative stress indicators. The blood levels of sICAM-1, sVCAM-1, endothelin-1, and sE-selectin were quantified; the activities of catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase and concentrations of reduced glutathione, oxidized glutathione, and thiobarbituric acid reactive susbtances, were also quantified before and after the treatment period. 3) Results: There were statistically significant (p < 0.05) decreases in systolic blood pressure, sVCAM-1, sE-selectin and endothelin-1 levels, and increases in glutathione peroxidase activity and oxidized glutathione levels. 4) Conclusion: The effects found in the present study agree with antihypertensive and antioxidant effects previously reported for Spirulina maxima. However, this is the first report about the effects on indicators of endothelial damage. More research in this field is necessary to gain an insight into the effects of Spirulina on these indicators.
REVIEW | doi:10.20944/preprints202103.0212.v1
Subject: Biology, Anatomy & Morphology Keywords: Cyanobacteria; Arthrospira; species concept; typus; species concept in prokaryotes
Online: 8 March 2021 (11:18:31 CET)
Cyanobacteria are prokaryotes whose taxonomy follows the same rules of a code (the International Botanical Nomenclature Code, IBNC) built for eukaryotic photosynthetic organisms. Hence, names of cyanobacteria follow the same rules and are assigned to biological entities (species) that should correspond to eukaryotic species. The main difficulty in the current situation is that the species concept in eukaryotes is based theoretically mainly on the biological species concept, that is centered on genetic exchange through sexual reproduction or lack of them. However, as shown, this difference is important from a theoretical point of view, but also in eukaryotes, the boundaries between different species are very rarely checked experimentally by direct observation of sexual barriers and hybridization events. The main concept for species delimitation is hence that related to morphology and, more recently and always in relation to morphology, DNA sequences. The introduction of distances obtained from matrixes of aligned sequences in the framework of a barcoding project provides a quantitative interpretation of species delimitation in relation to genetic distance that can be used both in eukaryotes and prokaryotes. However, the introduction of quantitative criteria needs the definition of distance thresholds to identify the boundaries between different species and, for doing that, it is necessary to test the distance thresholds in models of traditionally defined and recognized species. An alternative approach may be the comparison of the molecular distance (quantitative approach) to data about the capability of strains/species to exchange genetic information. Unfortunately data about this last question is still scarce. The adoption of molecular criteria to check species boundaries based on morphological characters has proved particularly challenging in cyanobacteria: a known example is provided. In conclusion, the only possible approach appears to be the association of molecular data to the increase of available data about the cell structure and the variation thereof in different physiological situations, particularly at the ultrastructural level. A further necessity is the check of the typus for a large number of cyanobacteria species, often based on old basionyms. In many of these cases the typus is often a drawing and more rarely a herbarium specimen or a microscope slide. In many cases an epitypification or a neotypification appears to be necessary.
ARTICLE | doi:10.20944/preprints201807.0470.v1
Subject: Chemistry, Food Chemistry Keywords: Arthrospira platensis; carotenoids; natural pigments; spirulina powder; C-phycocyanin; antioxidant activity
Online: 25 July 2018 (06:19:11 CEST)
Arthrospira platensis is the widely available source of spirulina and contains distinctive natural pigments including carotenoids and C-phycocyanin (C-PC). In this study, the major carotenoid and C-PC contents were determined in seven commercially available spirulina powder products and laboratory-prepared A. platensis trichomes (AP-1) by an LC-DAD method and a UV-Visible spectrometry, respectively. The correlation of these two pigment content levels with Hunter color coordinates and antioxidant activity was also evaluated. The L* value failed to show a significant correlation with pigment content, but a positive correlation was observed between a* values and the contents of total carotenoid and C-PC. As b* values decreased, the total carotenoid and C-PC contents increased. AP-1 exhibited the highest content of total carotenoids, chlorophyll a and C-PC, and antioxidant activities among the samples. This observation could be related to degradation of these pigments during the mass production process. The carotenoid profiles suggested that the commercial spirulina powders originated from two different sources, A. platensis and A. maxima. Total carotenoid and C-PC content exhibited positive significant correlations with antioxidant activities measured by DPPH and ABTS assays. These results provide a strong scientific foundation for the establishment of standards for the commercial distribution of quality spirulina products.