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Rugulopteryx okamurae is an invasive brown macroalga that has recently proliferated in the western Mediterranean Sea, causing significant environmental challenges. This alga, however, contains valuable bioactive compounds—alginate, mannitol, and phlorotannins—that can serve as biofertilizers to promote plant growth and aid in bioremediation of degraded or contaminated soils. This study focused on optimizing the extraction of these compounds from R. okamurae, transforming an ecological issue into a beneficial resource. Algae samples collected from the Spanish Mediterranean coast were processed through a randomized factorial response surface design. Extraction conditions varied by time, temperature, algae-to-solvent ratio, and ethanol-to-water ratio to determine optimal yields. The highest yields achieved were 29.4, 11.9, and 0.35 g/100 g for alginate, mannitol, and phlorotannin’s under extraction conditions of 6, 6, and 3 h; 58.8, 60.0, and 60.0 °C; and an algae:solvent ratio of 1:50, 2:45, and 1.40 g/mL, respectively. Characterization of the extracted sodium alginate using 1H-NMR, FTIR, and high-resolution electron microscopy confirmed its high purity and typical morphological features. This study highlights a sustainable approach to mitigating the invasive spread of R. okamurae while supporting soil health and sustainable agriculture. Harnessing this invasive species’ biofertilizer potential provides a dual solution, aiding marine ecosystem conservation and developing eco-friendly agricultural practices.

Saffron is one of the most appreciated, traditional, and expensive spices in the world. The objective of our study was to evaluate the effect of cooling the nutrient solution on the production, and organoleptic and commercial qualities of saffron grown in soilless culture. The nutrient solution was cooled to 4 to 5 °C whereas the control treatment was the fertigation supplied at ambient temperature. Corms were placed in a controlled cultivation chamber. The number of flowers per corms, and the weight and length of stigmas were measured. The amounts of safranal, crocin, and picrocrocin were analyzed spectrophotometrically according to the International Organization for Standardization [ISO/TS 3632-2 (2011) Normative]. Our results show that cooling of the nutritive solution increased flower production, the commercial phytochemical content, and organoleptic properties.

Benthic marine dioflagellate microalgae belonging to the genus Prorocentrum are a major source of okadaic acid (OA), OA analogues and polyketides. However, dinoflagellates produce these valuable toxins and bioactives in tiny quantities, and they grow slowly compared to other commercially used microalgae. This hinders evaluation in possible large-scale applications. The careful selection of producer species is therefore crucial for success in a hypothetical scale-up of culture, as are appropriate environmental conditions for optimal growth. A clone of the marine toxic dinoflagellate P. belizeanum was studied in vitro to evaluate its capacities to grow and produce OA as an indicator of general polyketide toxin production under the simultaneous influence of temperature (T) and irradiance (I0). Three temperatures and four irradiance levels were tested (18, 25 and 28 °C; 20, 40, 80 and 120 µE·m−2·s−1), and the response variables measured were concentration of cells, maximum photochemical yield of photosystem II (PSII), pigments and OA. Experiments were conducted in T-flasks, since their parallelepipedal geometry proved ideal to ensure optically thin cultures, which are essential for reliable modeling of growth-irradiance curves. The net maximum specific growth rate (µm) was 0.204 day−1 at 25 °C and 40 µE·m−2·s−1. Photo-inhibition was observed at I0 > 40 μEm−2s−1, leading to culture death at 120 µE·m−2·s−1 and 28 °C. Cells at I0 ≥ 80 µE·m−2·s−1 were photoinhibited irrespective of the temperature assayed. A mechanistic model for µm-I0 curves and another empirical model for relating µm-T satisfactorily interpreted the growth kinetics obtained. ANOVA for responses of PSII maximum photochemical yield and pigment profile has demonstrated that P. belizeanum is extremely light sensitive. The pool of photoprotective pigments (diadinoxanthin and dinoxanthin) and peridinin was not able to regulate the excessive light-absorption at high I0-T. OA synthesis in cells was decoupled from optimal growth conditions, as OA overproduction was observed at high temperatures and when both temperature and irradiance were low. T-flask culture observations were consistent with preliminary assays outdoors.

The 55-6 murine B cell hybridoma line not constitutively expressing CD40 was treated with increasing amounts of intact anti-mouse surface immunoglobulin G antibody (anti-mIgG) either not preincubated or preincubated for 48 h with lipopolysaccharide (LPS). In vitro, cross-linking of surface immunoglobulin G (sIgG) with the whole molecule of anti-IgG antibodies induced the expression of CD69, CD40, and CD19 surface antigens on 55-6 cells. The effect of sIgG ligation was dose-dependent, and preincubation with LPS enhanced their responsiveness to anti-mIgG stimulation. The expression of these surface molecules reached the maximum value during the first part of the cell cycle, corresponding to the position of the G1 peak of the DNA distribution. Stimulation of cells with anti-mIgG did not induce changes either in the number of viable cells or in the fraction of cells undergoing proliferation (mitosis). However, preincubation of 55-6 cells with LPS for 48 h before stimulation with anti-mIgG increased both the maximum specific growth rate (max) and the percentage of cells in the G2/M phase, in comparison with non-preincubated cells. Moreover, on cells preincubated with LPS prior to anti-mIgG treatment, specific IgG2a production rate was enhanced significantly compared to that obtained in control cultures. The correlation between the antibody production rate and the amount of IgG that is detectable on the cell surface was analyzed by flow cytometry. A good correlation between secreted and surface IgG was observed, and the results of cell cycle analyses demostrated that the 55-6 hybridoma cell line has a substantially higher sIgG content in G1 phase. [ABSTRACT FROM AUTHOR]

Fed-batch and perfusion cultures were carried out in a traditional glass 2-L bioreactor with the toxic dinoflagellate Protoceratium reticulatum. The maximum cell concentration obtained was 2.3 × 105cell·mL-1, which is almost 1 order of magnitude higher than the maximum previously referenced for this species. L1 medium was shown to be clearly deficient in nitrate and phosphate for this strain, and addition of highly concentrated aliquots of these nutrients allowed higher cell concentrations to be obtained. This species consumed high amounts of nitrate and phosphate, 2.1 × 10-3and 2.3 × 10-4mol·h-1·cell-1, respectively. However, this consumption produced a very low number of cells compared to other classes of microalgae, indicating that this species is, like other dinoflagellates, a poor competitor in terms of utilization of inorganic nutrients. Higher production of toxins and pigments was strongly associated with cell number in the culture, with maximum values of 700 ng·mL-1and 1321 g·mL-1, respectively. Most yessotoxins remained within the cells and not in the cell-free culture medium, and their production was not related to either the age of the culture or the cell growth phase. [ABSTRACT FROM AUTHOR]