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Analysis of the photosynthetic activity and the antioxidant capacity was carried out on the perennial forage grasses: English ryegrass (Lolium perenne L.), Tetramis cultivar, tall fescue (Festuca arundinacea Schreb.) Albena cultivar, meadow fescue (Festuca pratensis Huds.) selected population, red fescue (Festuca rubra L.) ecotype Ravnogor and smooth brome (Bromus inermis Leyss.) Nika cultivar. The analysis was performed during the summer and autumn periods of growth and development. As a basic physiological process, photosynthesis is tightly related to the plant tolerance to different stressors. In addition, tolerance to the secondary exerted oxidative stress directly depends on the antioxidant content. The analysis of the antioxidant capacity was performed by the methods of ferric and molybdate reduction. Photosynthetic activity and the amount of photoprotection were determined by chlorophyll fluorescence methods. The results show about a twofold higher increase in photosynthetic activity of the light phase in F. arundinacea, F. pratensis and B. inermis in summer, which increased with about 20% in L. perenne, F. arundinacea, 25% in F. rubra and decreased with about 15% in B. inermis in autumn. However, the levels of photoinhibition were comparatively low, indicating an absence of stress in practice. The antioxidant capacity was five times higher in the smooth brome from the Nika cultivar, as compared with the other grasses. The tall fescue from the Albena cultivar had the highest photosynthetic activity, uninhibited during the measurements under the high, as well as the low temperatures.

The choice of nitrogen source in a cultivation medium can specifically affect the physiology and biochemistry of microalgae. To increase the production of low-cost valuable biomass, the preferred nitrogen form for each alga should be determined. The aim of our study was to analyze the effects of different nitrogen sources and cultivation times on the growth, biochemical composition and the activities of glutamine synthetase, glutamate synthase, glutamate dehydrogenase, malate dehydrogenase, aspartate aminotransferase and proteases of Chlorella vulgaris R-06/2. Media supplemented with urea or ammonium nitrate provided similarly (p>0.05) high growth rates for a short cultivation time (4 days). The two nitrogen compounds applied simultaneously ensured better biomass yield but for prolonged cultivation. In the exponential growth phase, ammonium nitrate stimulated (p

Taking into account the rising trend of the incidence of cancers of various organs, effective therapies are urgently needed to control human malignancies. However, almost all chemotherapy drugs currently on the market cause serious side effects. Fortunately, several studies have shown that some non‐toxic biological macromolecules, including algal polysaccharides, possess anti‐cancer activities or can increase the efficacy of conventional chemotherapy drugs. Polysaccharides are characteristic secondary metabolites of many algae. The efficacy of polysaccharides on the normal and cancer cells is not well investigated, but our investigations proved a cell specific effect of a newly isolated extracellular polysaccharide from the red microalga Porphyridium sordidum. The investigated substance was composed of xylose:glucose and galactose:manose:rhamnose in a molar ratio of 1:0.52:0.44:0.31. Reversible electroporation has been exploited to increase the transport through the plasma membrane into the tested breast cancer tumor cells MCF‐7 and MDA‐MB231. Application of 75 µg/mL polysaccharide in combination with 200 V/cm electroporation induced 40% decrease in viability of MDA‐MB231 cells and changes in cell morphology while control cells (MCF10A) remained with normal morphology and kept vitality. [ABSTRACT FROM AUTHOR]

The red microalga Porphyridium cruentum, a potential source of bioactive substances, was the subject of a study on the effect of nutrients and different CO2 concentrations (0.04 and 2%) on the growth, biochemical composition and synthesis of phycobiliproteins and polysaccharides. For this purpose the alga was grown on two nutrition media, referred in this manuscript as M1 and M2 (M1 is richer in chloride and nitrogen substances). We have estimated that the abovementioned parameters varied under different cultivation conditions. Best yield was observed in M1 in the presence of 2% CO2, with a peak of the measured biomass equal to 4.0±0.1 g L-1. On the other side, compared to M1, M2 stimulated the pigment synthesis when the culture was enriched with 2% CO2. The highest amount of carbohydrates and pigments was observed when the alga was grown with 0.04% CO2. These results confirm that Porphyridium cruentum posesses great adaptive capabilities that can be used in future biotechnological practices. [ABSTRACT FROM AUTHOR]

Mycorrhizal fungi, algae and cyanobacteria are some of the most important soil microorganisms and major components of a sustainable soil-plant system. This study presents for the first time evidence of the impact of green alga and cyanobacterium solely and in combination with arbuscular mycorrhizal fungi (AMF) on plant-antioxidant capacity. In order to provide a better understanding of the impact of AMF and soil microalgae on Ocimum basilicum L. performance, changes in the pattern and activity of the main antioxidant enzymes (AOEs), esterases and non-enzymatic antioxidants including phenols, flavonoids, ascorbate, and α-tocopherols were evaluated. The targeted inoculation of O. basilicum with AMF or algae (alone and in combination) enhanced the antioxidant capacity of the plants and the degree of stimulation varied depending on the treatment. Plants in symbiosis with AMF exhibited the highest antioxidant potential as was indicated by the enhanced functions of all studied leaf AOEs: 1.5-, 2- and more than 10-fold rises of superoxide dismutase (SOD), glutathione-S-transferase (GST) and glutathione reductase (GR), respectively. The greatest increase in the total esterase activity and concentration of phenols, flavonoids and ascorbate was marked in the plants with simultaneous inoculation of mycorrhizal fungi and the green algae. 2,2-diphenyl-1-pycril-hydrazyl (DPPH) free radical scavenging method and ferric reducing antioxidant power (FRAP) assay proved the increased plant antioxidant capacity after co-colonization of green algae and mycorrhizae. [ABSTRACT FROM AUTHOR]

The influence of different nitrogen sources (ammonium nitrate, urea and ammonium nitrate + urea) and different concentration of the medium, containing both nitrogen sources on the growth and the content of pigment, protein, carbohydrate and lipid of a newly isolated green alga Scenedesmus sp. BGP was studied. Even though the two nitrogen sources were present in the medium routinely used in the lab, the experiments showed that the use of medium with each one of them separately gave a better yield of algal biomass for the whole cultivation period. The best growth was observed in urea-containing medium, where the dry weight reached 9.0 g/l. Dilution of the standard medium (2-, 4- and 8-fold) had positive impact on the growth, in contrast to 2-fold concentrated. The total amount of pigments (chlorophyll a+b and carotenoids) correlated with the change of growth in the different media. As a whole, carbohydrates, followed by proteins and lipids, dominated the biochemical composition of Scenedesmus sp. BGP. The biomass of the alga, grown in urea- or ammonium nitrate-containing medium was characterized by stable qualitative content over the entire period of cultivation (about 29% proteins, 41% carbohydrates and 24% lipids). These results showed that the medium with urea was most suitable for cultivation of Scenedesmus sp. BGP, because as a nitrogen source, urea is more efficient in terms of productivity and is less expensive. [ABSTRACT FROM AUTHOR]