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

Biosorption efficacy of living and non-living algal cells of Microcystis aeruginosa to toxic metals

The existence of metallic elements in the aquatic environment is recognized to cause acute destruction to aqueous life. This study depicts the prospective application of cyanobacterial strains of Microcystis aeruginosa as a sorption material of toxic elements, aluminium (Al), and cadmium (Cd) from aqueous solutions. Algal samples were revealed to the metal solution, a noticeable modification change in cell wall structure surface occurred. The Fourier-transform infrared (FTIR) analysis illustrated the reality of carboxyl, carbonyl, and hydroxyl moieties, which are liable for the uptake of essential and nonessential elements aluminium and cadmium, respectively. The results showed the ability of Microcystis aeruginosa to uptake Al and Cd at the optimal temperature, light, and pH by living and non-living cells in the concentration of 20 ppm and stimulated antioxidant resistance against oxidative stress. This finding divulged that Microcystis could be utilized as an efficient bio-sorbent for the elimination of these ions, especially Cd from freshwater

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

Effect of salinity, nitrogen and phosphorus stresses on growth and photosynthetic activity of the marine microalga Dunaliella parva

The growth of the marine green alga Dunaliella parva was studied and optimized under different salinity levels of NaCl (0.5, 1, 2, 2.5, and 3.5 M). The growth was monitored by cell number pigment content (Chl. a, Chl. b, and carotenoids). The grown alga, under the optimal conditions, was exposed to different stresses (nitrogen, phosphorus starvation, and salinity either singly or combined. Under nitrogen and phosphorus starvation, either singly or combined, the growth rate and the metabolic activities were decreased. Under salt stress (2.5 M NaCl) combined with N starvation and heavy metals stress, glycerol production increased, while glycerol synthesis decreased under salt stress of 1 M NaCl and P starvation. Also, free radicals (total antioxidant, reducing power, DPPH, and Lipid peroxidation), pigment content, and activity of antioxidant enzymes were recorded. D. parva grown under salinity level (2.5 M NaCl) combined with nutrient starvation correlated with more efficient enzymatic antioxidant activity accumulation. This study strongly suggested that the induction of antioxidant defense was one component of the tolerance mechanism of D. parva to salinity, as evidenced by its growth behavior

Endophytic Bacillus vallismortis and Bacillus tequilensis bacteria isolated from medicinal plants enhance phosphorus acquisition and fortify Brassica napus L. vegetative growth and metabolic content

Phosphorus fertilization imposes critical limitations on crop productivity and soil health. The aim of the present work is to explore the potential of two phosphate solubilizing bacteria (PSB) species in phosphorus supplementation of canola (Brassica napus L.). Out of 38 bacterial isolates obtained from nine medicinal plants, two bacterial strains (20P and 28P) were proved as the most potent for the in-vitro tricalcium phosphate solubilization test. These isolates verified their activity toward different enzymes as nitrogenase and alkaline phosphatase. Also, 20P and 28P gave a high amount of indole-3-acetic acid, 34.16 μg/ml and 35.20 μg/ml, respectively, and were positive for siderophores production as they detected moderate affinity for iron chelation. Molecular identification confirmed that strain 20P was Bacillus vallismortis and strain 28P was Bacillus tequilensis. A pot experiment was conducted to study the effect of four different phosphorus concentrations (0%, 50%, 75%, and 100% P) each alone and/or in combination with B. vallismortis, B. tequilensis, or both bacterial isolates on the vegetative growth and some physiological parameters of canola. The combined treatment of 50% phosphorus + (B. vallismortis + B. tequilensis) was generally the most effective with respect to shoot height, shoot dry mass, leaf area, photosynthetic pigment fractions, total sugar content, and accumulated NPK content. In contrast, the rhizosphere pH reached the minimum value under the same treatment. These findings highlighted the potential use of PSB (B. vallismortis and B. tequilensis) along with phosphorus fertilization as a safe sustainable tactic

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

Handbook of research on algae as a sustainable solution for food, energy, and the environment Practice, progress, and proficiency in sustainability (PPPS) book series./ Mostafa M. El-Sheekh, Norhayati Abdullah, Imran Ahmad.

Includes bibliographical references and index."This book provides an opportunity to the readers to understand about the biological and biotechnological processes going on in the cultivation and harvesting of algae, DNA sequencing, and genomics of algae, giving detailed insight into various applications of algal biomass in agriculture, food, feed, and medicines"--1 online resource (xxxviii, 795 pages)

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