The Influence of Different Light Wavelengths on Growth, Enzymes Activity and Photosynthesis of the Marine Microalga Dunaliella parva W.Lerche 1937

يعتبر الضوء عاملاً هامًا يؤثر على نمو الطحالب الدقيقة وكفاءة التمثيل الضوئي لها ؛ ومع ذلك ، لا يُعرف الكثير عن كيفية تأثير شدة الضوء مع الطول الموجي على قدرة التمثيل الضوئي ونمو الطحالب البحرية الدقيقة. في هذه الدراسة ، تمت دراسة نمو الطحالب البحرية الخضراء الدقيقة ديوناليلا بارفا  واقلمته تحت شدة الضوء المختلفة (25 ~ 70 μmol m-2 s-1) ونوعية الضوء (الأزرق والأخضر والأحمر) مقارنة بالضوء الأبيض عند 40 μmol m-2 s-1  كتجربة ضابطة (كنترول). تمت مراقبة النمو عن طريق حساب عدد الخلايا ومحتوى الصبغة وتراكيز Chl a و Chl b والكاروتينات. تم تسجيل النمو الأمثل وأعلى كفاءة التمثيل الضوئي (Fv / Fm) بكثافة ضوء 40 μmol m-2 s-1 ، ضوء أبيض ، و 1.25 مولار كلوريد الصوديوم (. 1.47 and 0.678×106 cell mL-1، على التوالي). أظهر نشاط إنزيمات مضادات الأكسدة ، بما في ذلك الكاتلاز والبيروكسيديز وكذلك محتوى الأسكوربات ، أعلى قيم بلغت 0.190 µM/min.mg Chl, 0.434 and 13.3 mg/g f.wt.  على التوالي ، تحت تأثير  الضوء الأخضر ، الذي أكد وجود ضغوط بيئية.Light is an important factor that influences the growth and photosynthetic efficiency of microalgae; however, little is known about how light intensity together with the wavelength affect the photosynthetic capacity and growth of marine microalgae. In the present study, the growth of the marine green microalga Dunaliella parva was studied and optimized under different light intensities (25 ~ 70 μmol m-2 s-1) and qualities (blue, green, and red) in comparison with white light at 40 μmol m-2 s-1 as a control. The growth was monitored by counting the cell number, pigment content, Chl a, Chl b, and carotenoids concentrations. The optimal growth and highest photosynthetic efficiency (Fv/Fm) were recorded at a light intensity of 40 μ mol m-2 s-1, white light, and 1.25 M NaCl (1.47 and 0.678×106 cell mL-1, respectively). The activity of antioxidant enzymes, including catalase and peroxidase, as well as ascorbate content, showed the highest values of 0.190 µM/min.mg Chl, 0.434 and 13.3 mg/g f.wt. respectively, under the green light, which confirmed the presence of environmental stresses

Evaluation of Polycladia myrica mediated selenium nanoparticles (PoSeNPS) cytotoxicity against PC-3 cells and antiviral activity against HAV HM175 (Hepatitis A), HSV-2 (Herpes simplex II), and Adenovirus strain 2

IntroductionThe trace element selenium is an essential micronutrient for the health of humans, animals, and microbesMany researchers have recently become interested in selenium nanoparticles (SeNPs) because of their biocompatibility, bioavailability, and low toxicity. Consequently, selenium nanoparticles are widely used in various biomedical applications and wastewater bioremediation due to their greater bioactivity. Green biosynthesis of nanoparticles is common and preferable nowadays.MethodsIn this work, the selenium nanoparticles were synthesized using the brown seaweed Polycladia myrica aqueous extract and characterized using seven parameters, SEM, TEM, UV spectra, Zeta potential, EDX, X-ray differaction and FTIR, then examined for their cytotoxicity using PC-3 cells and normal mammalian cells from the African green monkey kidney (Vero) were used to test the effectiveness of the produced Polycladia myrica mediated selenium nanoparticles as an anticancer agent and antiviral activity against HAV HM175 (Hepatitis A), HSV-2 (Herpes simplex II), and Adenovirus strain 2.ResultsThe phycosynthesized nanoparticles exhibit antiviral activity (40.25 ± 2.61, 8.64 ± 0.82, and 17.39 ± 1.45%) against HAV-10, Adenovirus, and HSV-2, respectively. The IC50 values of the two cell types human prostate PC-3 and Vero were 123.51 ± 4.07 g/mL and 220.53 ± 6.89 g/ mL, respectively. The maximum inhibitory percent was 86.15 ± 2.31 against PC-3 cells. At the same time, at a concentration of 125 g/mL.DisscusionThis work showed that PoSeNPS have good antiviral activity against HAV-10 virus with an antiviral percent of 40.25%, despite weak antiviral activity against Adenovirus and HSV-2 with antiviral percent (8.64% and 17.39%), respectively. The cytotoxicity effect of these nanoparticles was determined against PC-3 with a maximum inhibitory percent of 80.53%. These nanoparticles have no hazardous effect against normal Vero cells as the viability percent was (78.39% and 49.23%) for Vero cells and PC-3 cells, respectively, at 125 μg/mL

Aplicaciones farmacéuticas e impactos ambientales de la Spirulina (Arthrospira). Una visión general

Recently, microalgae cultivation for different applications, including the production of nutritional and pharmaceutical active compounds has received increasing attention. Among the different genera, Spirulina (Arthrospira sp.) is one of the most promising blue-green microalgae (Cyanophyta) because it is rich in antioxidants, essential amino acids (EAAs), minerals, proteins, polyunsaturated fatty acids and vitamins. It has a high protein content (60-70% of the dry weight), which is a complete protein, i.e. containing all EAAs. Therefore, Spirulina is currently a commercial product with high nutritional value and also a significant source of complementary and alternative medicine. The objective of the present work was to review the pharmaceutical and therapeutic applications of Spirulina, especially its antioxidant, anti-inflammatory, anti-cancer, anti-microbial, anti-diabetic, anti-obesity and anti-toxicity properties. The results were obtained from experiments in the literature performed in vitro and in vivo using experimental animals. The main reported active ingredients in Spirulina include phycocyanin, tocopherol, β-carotene, caffeic acids and chlorogenic acid, which showed individual or synergetic effects. In addition, the present review discusses the future perspectives of genetically modified Spirulina as a source for industrial products while producing valuable biomass photoautotrophically. Furthermore, the consequent environmental impacts of large-scale cultivation of Spirulina are discussed.Recientemente, el cultivo de microalgas para diferentes aplicaciones, incluida la producción de compuestos activos nutricionales y farmacéuticos, está recibiendo una atención cada vez mayor. Entre los diferentes géneros, Spirulina (Arthrospira sp.) es una de las microalgas azul-verde más prometedoras (Cyanophyta) porque es rica en antioxidantes, aminoácidos esenciales (EAAs), minerales, proteínas, ácidos grasos poliinsaturados y vitaminas. Tiene un alto contenido de proteína (60-70% del peso seco) es una proteína completa, es decir, contiene todos los EAAs. Por lo tanto, la Spirulina es actualmente un producto comercial con alto valor nutricional y también una fuente importante parala medicina complementaria y alternativa. El objetivo del presente trabajo es revisar las aplicaciones farmacéuticas y terapéuticas de Spirulina, especialmente propiedades antioxidantes, antiinflamatorias, anticancerígenas, antimicrobianas, antidiabéticas, antiobesidad y antitóxicas. Los resultados se obtienen a partir de trabajos experimentales realizados in vitro e in vivo utilizando animales de experimentación. Los principales ingredientes activos reportados en Spirulina incluyen ficocianina, tocoferol, β-caroteno, ácidos caféicos y clorogénico que mostraron efectos individuales o sinérgicos. Además, en la presente revisión se discute las perspectivas futuras de la Spirulina genéticamente modificada como fuente de productos industriales, al mismo tiempo que se produce una valiosa biomasa fotoautotrófica. Además, se discutieron los impactos ambientales consiguientes del cultivo a gran escala de la Spirulina

Outdoor Cultivation of Spirulina platensis for Mass Production

In the present study, the blue-green alga Spirulina platensis (NRC) was used for mass production under outdoor cultivation in three open ponds with a final capacity of 75 m3 net cultivation volume. Subculturing was performed within sequences and gradual volumes till 1,200 L open plate photobioreactor. The first and second ponds (30 cm depth) were used for the actual continuous production, while the third pond (80 cm depth) was used as a continuous inoculum supplier. In spite of low turbulence of the third pond due to high depth, all ponds had the same mechanical specification concerning paddle wheel structure and turbulence rate (16 rpm). A final nutrient concentration was employed based on Zarrouk medium by commercial grade compounds with some modifications. The nutrition was performed for the third pond by extra supplementation of extra doses of macro and micro-nutrients during the production period and dilution took place when culture was transferred to production ponds (first and second). Each production pond was harvested every 48 hours and the remainder water was return again into the third pond. The harvested pond yielded about 40 kg per day of fresh algal weight containing about 85% moisture on a dry weight basis. The results proved that using urea as nitrogen and carbon source with corn steam liquor instead of sodium nitrate and low bicarbonate, reduces production cost and supports growth medium by an adequate amount of carbon dioxide on the expense of the luxury use of sodium bicarbonate (16.8 g.l-1). Chemical analysis of the produced biomass showed 58-62% crude protein, 6-8% of ether extract and 8-11% of total carbohydrates. S. platensis contained total essential amino acids (131.3 mg/g), with a predominance of arginine followed by glutamic acid, leucine and phenylalanine

Induction of the synthesis of bioactive compounds of the marine alga Tetraselmis tetrathele (West) Butcher grown under salinity stress

This work aims at the induction of the synthesis bioactive compounds in microalgae which are used in aquacultures. Experiments were done using Tetraselmis tetrathele in batch culture for 8 days under different salinity levels. The growth of the alga at salinity 20 ppm was increased by fivefold and synthesis of carotenoids by 20-fold in comparison to the controlled. Increasing NaCl concentration resulted in increasing the fatty acid accumulation in T. tetrathele cells. Saturated fatty acids were the main constituent in the fatty acid methyl esters (FAMEs) (3.48 mg/g) at salinity 25 ppm. The predominated fatty acids were tridecylic, myristic and pentadecanoic which have potential antimicrobial activities. GC–MS analyses of the alga acetone extract grown under different NaCl concentrations were established. The results showed the presence of 18 bioactive compounds: 9-octadecenamide; in addition to the different esters of some fatty acids: hexanedioic, 1,2-cyclohexanedicarboxylic, phthalic, oleanitrile, hexanedioic and 1,2-cyclohexanedicarboxylic (71.5%; 64.9%; 55.4%; 49.6%; 18.7%; 25.2% and 14.5%, respectively). The study suggested that the alga biosynthesized various bioactive compounds under different salinity levels as defense mechanisms. Accordingly, the growth of T. tetrathele under salinity stress before being used in aquacultures is recommended

Effect of salt stress on antioxidant system and the metabolism of the reactive oxygen species in Dunaliella salina and Dunaliella tertiolecta

The physiological and biochemical adaptations of two chlorophytes Dunaliella salina and Dunaliella tertiolecta developed to extreme saline environment were assessed in the present study. Both Dunaliella cultures were treated with a range of NaCl concentrations ranging from 0.05 to 4 M NaCl and the influence of salinity on growth and antioxidant parameters were determined. Biomass yields, chlorophyll and carbohydrate contents were reduced at salinity extremes. Protein contents were elevated under low salinities. No evidence or for large change was found in soluble amino acids during salinity stress. Osmoregulation is mediated by glycerol as compatible solute in both Dunaliella species. The maximum glycerol production was observed at high growth salinities. Under hyposaline conditions, a low content of β-carotene was noticed, whereas hypersaline conditions induced an increase in this product, about 1.4 and 1.1-fold more than its value at optimum salinities for D. salina and D. tertiolecta, respectively. An exposure to 0.5, 0.1, and 4 M NaCl increased H2O2 contents were positively correlated with the level of thiobarbituric acid reactive substances. The levels of six antioxidant enzymes (superoxide dismutase, catalase, peroxidase, ascorbate peroidase, glutathione reductase and glutathione S-transferase) and two antioxidant substrates (glutathione and ascorbic acid) were quantified. The data revealed a differential response between D. salina and D. tertiolecta in response to different salinity levels. The involvement of oxidative stress at various salinity levels is implied by the alterations in antioxidant enzymes and substrates, but the specific changes are very different between hypo and hypersaline stress conditions.Key words: Antioxidant system, β-carotene, Dunaliella, glycerol, reactive oxygen species, salt stress

In vitro anticancer activity of polysaccharide extracted from red alga Jania rubens against breast and colon cancer cell lines

Objective: To evaluate the potential role of the polysaccharides of the marine algae as an anticancer agent in vitro against colon cancer cell line (CoCa2) and breast cancer (MCF7) cell lines and to measure lactate dehydrogenase enzyme (LDH) activity as biomarker of membrane integrity of the cells. Methods: The cells of breast cancer (MCF7) and colon cancer (CoCa2) were used to evaluate the potential anticancer role of the polysaccharides of marine algae. Anti-proliferative activity against MCF7 and CoCa2 cell lines were evaluated in vitro by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Results: The in vitro assay of the antioxidant activity of eight marine seaweed species showed that the red seaweed Jania rubens (J. rubens) had the highest DPPH (2,2 diphenyl-1-picrylhydrazyl) free radical scavenging activity. The extracted polysaccharides with concentrations 0.1–40.0 mg/mL from J. rubens were tested for its anticancer potentiality and cytotoxic effects against the cell lines of human breast (MCF7) and colon cancer (CoCa2) cell lines by MTT assay. The inhibitory concentration at 50 (IC50) value the of J. rubens polysaccharide extract was 0.312 5 mg/mL for MCF7 and 20 mg/mL for CoCa2. LDH activity and annexin V concentration were higher in the treated MCF7 and CaCo2 cells than in the untreated ones. Quantitative polymerase chain reaction technique indicated that the polysaccharide treatments caused up-regulation of Bax, caspase 8 and P53 genes expression in CoCa2 cells, and up-regulation of caspase 3 and down-regulation of Bcl2 genes expression in MCF7 cells. Conclusions: The polysaccharides of the red marine alga J. rubens could be a potential candidate for the natural compounds as antioxidant and anticancer therapy

Antimicrobial activity of some seaweeds species from Red sea, against multidrug resistant bacteria

This study evaluates the antibacterial activity of diethyl ether, methanol, ethanol and chloroform extracts of red algae Ceramium rubrum (Rhodophyta), Sargassum vulgare, Sargassum fusiforme and Padina pavonia (Phaeophyta) collected from Red sea, Egypt. The algal extracts were tested for their antibacterial activity against ten multidrug resistant clinical isolates of Gram positive and Gram negative bacteria. The highest inhibition activity among all extracts was obtained with 100 μl diethyl ether extract S. fusiforme against Staphylococcus aureus 2 and 50 μl ethanol extract of S. vulgare against Klebsiella pneumoniae. The algal extract of S. fusiforme and S. vulgare was characterized by Gas chromatography–mass spectrometry (GC–MS). The compounds with antimicrobial activity were identified, such as phenols, terpenes, acetogenins, indoles, fatty acids and volatile halogenated hydrocarbons. Transmission electron microscopy was applied for determining the morphological changes in S. aureus 2 and K. pneumonia treated with 100 μl diethyl ether extract of S. fusiforme and 50 μl ethanol extract of S. vulgare, respectively. Perforation of cell wall, leakage of cytoplasmic contents, severe distortion of outer cell shape, inner chromatin mild scattered cytoplasmic vacuolation, rupture of cell wall, and decreased cell size for both bacterial isolates treated with 100 μl diethyl ether of S. fusiforme extract and 50 μl S. vulgare ethanolic extract were recorded