Effect of elicitation and precursor feeding on accumulation of 20-hydroxyecdysone in <Emphasis Type="Italic">Achyranthes aspera</Emphasis> Linn. cell suspension cultures

20-Hydroxyecdysone is one of the most common ecdysteroids in plants with potential therapeutic applications. In this study, cell suspension cultures of Achyranthes aspera were raised in shake flasks to investigate the production of 20-hydroxyecdysone. The quantification and characterization of 20-hydroxyecdysone in the cultures were done by High performance liquid chromatography (HPLC) and Liquid Chromatography-quadrupole time-of- flight mass spectrometry (LC-Q-TOF) analyses. For raising the suspension, calli initiated from in vitro grown leaf explants were cultured in liquid Murashige and Skoog (MS) medium augmented with combinations of 2, 4-dichlorophenoxyacetic acid (1 mg L^?1) and α-naphthaleneacetic acid (1 mg L^?1). Maximum growth index of the cell suspension was 9.9, which was achieved during 20th day of culture (final phase of exponential growth). At this stage, the biomass accumulated was 1.09 ± 0.09 g dry weight (DW) and the 20-hydroxyecdysone concentration was 0.24 mg g^?1 DW. Eliciting the cultures with 0.6 mM Methyl jasmonate for 6 days; enhanced the production of 20-hydroxyecdysone production to 0.35 mg g^?1 DW. By augmenting the cultures with the precursors namely cholesterol (10 mg L^?1) and 7-dehydrocholesterol (10 mg L^?1), production of 20-hydroxyecdysone was boosted to 0.31 mg g^?1 DW and 0.28 mg g^?1 DW respectively.     

Evaluation of growth and biomass production of Arthrospira (Spirulina) fusiformis in laboratory cultures using waters from the Ethiopian soda lakes Chitu and Shala

The cost of nutrient media is the major challenge for biomass production of Spirulina. Although much effort has been made to use enriched seawater for the cultivation of this microalga, little attention has been given to the potential of water of soda lakes. In this study, growth (μ, day^?1) and biomass production (B) of Arthrospira fusiformis cultivated using waters of the soda lakes Chitu and Shala with or without supplementation were evaluated. Comparable μ and B values were achieved in both Lake Chitu water-based media (CBM) and Lake Shala water-based media (SBM), with slightly higher values in the latter. Both CBM and SBM supplemented with the standard Spirulina medium (SM) by 25 % and 50 % supported considerably higher μ and B. The pH and salinity of the cultures showed significant variations (P?μ and B. The observed higher μ and B were probably associated with the reduction in pH and salinity of the supplemented media due to addition of bicarbonate–carbonates and dilution, and provision of the limiting nutrient nitrogen. The higher μ and B in SBM may have resulted from some of their aggregate chemical parameters, which were closer to those in the SM, and abundant PO₄-P. This seems to suggest that Lake Shala water is more conducive to Arthrospira. We contend that 25 % and 50 % supplemented Lake Shala water can be preferably used to produce Arthrospira biomass, thereby reducing the cost of nutrients by 75 % and 50 %, respectively.     

Accumulation of rosmarinic, chlorogenic and caffeic acids in in vitro cultures of Eryngium planum L.

Eryngium planum L. cell and organ cultures were maintained on Murashige and Skoog media (MS), supplemented with exogenous hormones of different types and various concentrations for high biomass growth. The callus and cell suspension cultures were treated with increased sucrose concentration and/or elicited by methyl jasmonate for the enhancement of selected phenolic acids accumulation. Three phenolic acids, rosmarinic acid (RA), chlorogenic acid (CGA) and caffeic acid (CA), were detected by HPLC-DAD in those cultures. The sum of their content in the dry material was found to be higher in the shoot culture (3.95 mg g^?1), root culture (7.05 mg g^?1), callus (6.20 mg g^?1) and cell suspension (2.04 mg g^?1) than in the leaves (1.87 mg g^?1) and roots (0.76 mg g^?1) of intact plants. The major compound of in vitro cultures was always rosmarinic acid. The content of RA could be increased approximately threefold (16.24 mg g^?1) in the callus culture and approximately twofold (3.91 mg g^?1) in the cell suspension culture by elicitation with 100 μM methyl jasmonate (MeJA). The higher concentration of sucrose (S) in the medium (5, 6 %) led to over a twofold increase of CGA content in the callus culture (2.54 mg g^?1). The three mentioned phenolic acids have been found in E. planum undifferentiated and differentiated in vitro cultures for the first time.     

Accumulation of arsenic in soil and rice under wetland condition in Bangladesh

Shallow tube well (STW) water, often contaminated with arsenic (As), is used extensively in Bangladesh for irrigating rice fields in the dry season, leading to potential As accumulation in soils. In the current study the consequences of arsenic from irrigation water and direct surface (0–15 cm) soil application were studied under field conditions with wetland rice culture over 2 years. Twenty PVC cylinders (30-cm length and 30-cm diameter) were installed in field plots to evaluate the mobility and vertical distribution of soil As, As mass balance, and the resulting influences on rice yield and plant-As concentration in Boro (dry season) and transplanted (T.) Aman (wet season) rice over the 2-year growth cycle. Treatments included irrigation-water As concentrations of 0, 1 and 2 mg L^?1 (Boro season only) and soil-As concentrations of 10 and 20 mg kg^?1. Following the 2-year cropping sequence the major portion (39.3–47.6%) of the applied arsenic was retained within the rooting zone at 0–15 cm depth, with 14.7–19.5% of the total applied As at the 5–10 cm and 10–15 cm soil depths compared to 1.3–3.6% at the 35–40 cm soil depth. These results indicate the relatively low mobility of applied As and the likely continued detrimental accumulation of As within the rooting zone. Arsenic addition in either irrigation water or as soil-applied As resulted in yield reductions from 21 to 74 % in Boro rice and 8 to 80 % in T. Aman rice, the latter indicating the strong residual effect of As on subsequent crops. The As concentrations in rice grain (0.22 to 0.81 µg g^?1), straw (2.64 to 12.52 µg g^?1) and husk (1.20 to 2.48 µg g^?1) increased with increasing addition of As. These results indicate the detrimental impacts of continued long-term irrigation with As-contaminated water on agricultural sustainability, food security and food quality in Bangladesh. A critical need exists for the development of crop and water management strategies to minimize potential As hazard in wetland rice production.     

Feeding elicitors and precursors enhance colchicine accumulation in morphogenic cultures of <Emphasis Type="Italic">Gloriosa superba</Emphasis> L.

Morphogenic cultures of Gloriosa superba were initiated on Murashige and Skoog’s medium fortified with 2 mg L^?1 2,4-dichlorophenoxyacetic acid (2,4-D), 0.5 mg L^?1 naphthaleneacetic acid (NAA), 4% sucrose and 0.1% activated charcoal. To enhance the content of the alkaloid colchicine, morphogenic cultures were treated with different concentrations of abiotic elicitors like signalling compounds, metals, biotic elicitors, precursors and a combination of elicitors. Signalling molecules like acetyl salicylic acid (ASA) and sodium nitroprusside improved the production of colchicine. Abiotic elicitors have markedly (p?≤?0.05 or ≤?0.01) enhanced the colchicine content either at lower or higher concentrations. Among the metals, the highest amount of 11.67 mg of colchicine g^?1 dry wt was noticed at 60 mM rubidium chloride, followed by 60 mM NaCl (11.18 mg g^?1). Contrarily, in the presence of biotic elicitors such as Fusarium oxysporum, Alternaria solani, and Saccharomyces cerevisiae, colchicine content ranged only between 2 and 5.32 mg g^?1, but Bacillus subtilis repressed it. Among the aromatic amino acids, phenylalanine at 500 mg L^?1 influenced the highest accumulation of 19.48 mg g^?1 dry tissue, followed by tryptophan (12.47 mg g^?1), and tyrosine (9.87 mg g^?1), a direct precursor of colchicine biosynthesis, while intact tubers and leaves contained 4.65 and 4.16 mg of colchicine g^?1 dry tissue respectively. A combination of 10 µM AlCl₃ and 50 µM salicylic acid (SA) registered 17.34 mg g^?1 followed by 16.24 mg g^?1 tissue in presence of 1 µM HgCl₂ and 50 µM SA. The results suggest that the elicitor-stimulated colchicine accumulation was a stress response and can be exploited further for commercial production.     

Selective fengycin production in a modified rotating discs bioreactor

Production of lipopeptides fengycin and surfactin in rotating discs bioreactor was studied. The effects of rotation velocity and the addition of agitators between the discs on volumetric oxygen transfer coefficient k _L a were firstly studied in model media. Then the production of lipopeptides was also studied at different agitation conditions in the modified bioreactor (with agitators). The effect of agitation on dissolved oxygen, on submerged and immobilized biomass, on lipopeptide concentrations and yields and on the selectivity of the bioreaction was elucidated and discussed. The proposed modified rotating discs bioreactor allowed to obtain high fengycin concentrations (up to 787 mg L^?1), but also better selectivity of the bioreaction towards fengycin (up to 88 %) and better yields of fengycin per glucose (up to 62.9 mg g^?1), lipopeptides per glucose (up to 71.5 mg g^?1), fengycin per biomass (up to 309 mg g^?1) and lipopeptides per biomass (up to 396 mg g^?1) than those reported in the literature. Highest fengycin production and selectivity were obtained at agitation velocity of 30 min^?1. The proposed non-foaming fermentation process could contribute to the scale-up of lipopeptide fermentors and promote the industrial production of fengycin. The proposed bioreactor and bioprocess could be very useful also for the production of other molecules using bioprocesses requiring bubbleless oxygen supply.     

Elicitor mediated enhancement of wedelolactone in cell suspension culture of <Emphasis Type="Italic">Eclipta alba</Emphasis> (L.) Hassk

The present research focused on enhancing the production of wedelolactone through cell suspension culture (CSC) in Eclipta alba (L.) Hassk. With an aim of attaining a sustainable CSC, various plant growth regulators, elicitors and agitation speed were examined. Nodal segments of in vitro propagated plantlets induced the maximum percentage (93.47?±?0.61%) of callus inoculated on Murashige and Skoog (MS) medium fortified with picloram (2 mg L^?1). The growth kinetics of CSC exhibited a sigmoid pattern with a lag phase (0–6 days), a log phase (6–18 days), a stationary phase (18–24 days) and then death phase thereafter. The highest biomass accumulation in CSC with 7.09?±?0.06 g 50 mL^?1 fresh weight, 1.52?±?0.02 g 50 mL^?1 dry cell weight, 1.34?±?0.01?×?10⁶ cell mL^?1 total cell count and 57.00?±?0.58% packed cell volume was obtained in the liquid MS medium supplemented with 1.5 mg L^?1 picloram plus 0.5 mg L^?1 kinetin at 120 rpm. High performance thin layer chromatography confirmed that yeast extract (biotic elicitor) at 150 mg L^?1 accumulated more CSC biomass with 1.22-fold increase in wedelolactone (288.97?±?1.94 µg g^?1 dry weight) content in comparison to the non-elicited CSC (237.78?±?0.04 µg g^?1 dry weight) after 120 h of incubation. Contrastingly, methyl jasmonate (abiotic elicitor) did not alter the biomass but increased the wedelolactone content (259.32?±?1.06 µg g^?1 dry weight) to an extent of 1.09-fold at 100 µM. Complete plantlet regeneration from CSC was possible on MS medium containing N⁶-benzyladenine (0.75 mg L^?1) and abscisic acid (0.5 mg L^?1). Thus, the establishment of protocol for CSC constitutes the bases for future biotechnological improvement studies in this crop.     

Effect of culture conditions, cytokinins, methyl jasmonate and salicylic acid on the biomass accumulation and production of withanolides in multiple shoot culture of Withania somnifera (L.) Dunal using liquid culture

The influence of cytokinins and culture conditions including medium volume, harvest time and elicitation with abiotic elicitors (SA/MeJ) have been studied for the optimal production of biomass and withanolides in the multiple shoot culture of Withania somnifera. Elicitation of shoot inoculum mass (2 g l^?l FW) with SA at 100 μM in the presence of 0.6 mg l^?l BA and 20 mg l^?l spermidine for 4 h exposure time at the 4th week in 20 ml liquid medium recorded higher withanolides production (withanolides A [8.48 mg g^?l DW], withanolides B [15.47 mg g^?l DW], withaferin A [29.55 mg g^?l DW] and withanone [23.44 mg g^?l DW]), which were 1.14 to 1.18-fold higher than elicitation with MeJ at 100 μM after 5 weeks of culture. SA-elicited cultures did not exhibit much variation in biomass accumulation when compared to control. This cytokinin induces and SA-elicited multiple shoot culture protocol provides a potential alternative for the optimal production of biomass and withanolides utilizing liquid culture.     

Scale-up of adventitious root cultures of Echinacea angustifolia in a pilot-scale bioreactor for the production of biomass and caffeic acid derivatives

In an attempt to scale-up of adventitious root cultures of Echinacea angustifolia for the production of biomass and caffeic acid derivatives, i.e. echinacoside, chlorogenic acid, cichoric acid, caftaric acid, and cynarin, the effects of Murashige and Skoog (MS) medium dilutions, and initial sucrose concentrations were investigated in a 5-L airlift bioreactor. In addition, the kinetics of adventitious root growth and accumulation of secondary metabolites were also studied. The greatest root dry weight (6.50 g L^?l) and accumulation of total phenolics [22.06 mg g^?1 DW (dry weight)], total flavonoids (5.77 mg g^?1 DW) and total caffeic acid derivatives (10.63 mg g^?1 DW) were obtained at quarter-strength MS medium. Of the various gradients of sucrose tested, 5 % sucrose supplementation was regarded as an optimal concentration for enhancing productivity of biomass and bioactive compounds. Neither higher salt strength (3/4–2 MS) nor sucrose concentrations (7 and 9 %) showed promotive effect on root growth and metabolite production. The kinetic studies revealed that 4 weeks of culture period is the optimal time to achieve highest productivity of metabolites. Based on these results, a large-scale (20 L) and a pilot-scale (500 L) adventitious root culture system was established. In the pilot-scale bioreactor, adventitious roots were elicitor-treated with 100 μM methyl jasmonate (MJ) on day 28. After 1 week of elicitation, 1.75 kg dry root biomass was harvested containing 60.41 mg g^?1 DW of total phenolics, 16.45 mg g^?1 DW of total flavonoids, and 33.44 mg g^?1 DW of total caffeic acid derivatives. Among the caffeic acid derivatives, the accumulation of echinacoside (the major bioactive compound) in MJ-treated adventitious roots grown in the 500-L bioreactor was the highest (12.3 mg g^?1 DW), which is approximately threefold more than the non-MJ-treated roots cultured in 5- and 20-L bioreactors.     

Light-induced production of antidepressant compounds in etiolated shoot cultures of Hypericum hookerianum Wight & Arn. (Hypericaceae)

Hypericum hookerianum is a lesser known ethnomedicinal plant having wound healing, antitumor and anti-HSV-1 properties. Isolated nodes of in vitro shoots sub-cultured in the dark for 4 weeks on half strength Murashige and Skoog medium solidified with Gelzan (1.5 g l^?1), and supplemented with 2.325 μM kinetin produced 8.0 ± 0.40 etiolated shoots of 5.0 ± 0.62 cm length at 74 % efficiency versus 9.2 ± 0.6 healthy shoots of 4.4 ± 0.5 cm obtained from nodes in light at 96 % efficiency. Low concentrations of hypericin were found in wild plant [0.35 ± 0.09 mg g^?1 dry weight (DW)] and control green shoot cultures (0.91 ± 0.03 mg g^?1 DW). Etiolated shoots exposed to a 12 h photoperiod (50 μmol m^?2 s^?1) through 1–25 days turned red incrementally due to synthesis and accumulation of 0.1–3.83 mg g^?1 DW hypericin in sub-epidermal cortical cells of the stem and varied shaped cells of the distorted mesophyll. Flavonoid and anthocyanin concentrations of the etiolated shoots subjected to the 12 h photoperiod were 3–5 fold higher than the control shoot cultures while total chlorophylls [1.97 ± 0.05 mg g^?1 fresh weight (FW)] of the light exposed shoots were significantly less compared to the control (2.86 ± 0.18 mg g^?1 FW) and natural plant (6.82 ± 0.29 mg g^?1 FW). HPLC analysis of shoot extracts revealed the presence of 0.14 ± 0.03, 0.16 ± 0.02 and 1.45 ± 0.16 mg g^?1 DW hyperforin in wild plant, control shoot cultures and etiolated shoot cultures illuminated for 25 days, respectively. Despite a reasonable presence in etiolated shoots (0.61 ± 0.15 g^?1 FW), total phenols did not increase significantly during illumination. The results indicate light induced synthesis of anti-depressant phenolic derivatives (hypericin, hyperforin and flavonoids) in etiolated shoot cultures of H. hookerianum.     

Biomass and terpenoids produced by mutant strains of <Emphasis Type="Italic">Arthrospira</Emphasis> under low temperature and light conditions

The filamentous Cyanobacterium Arthrospira is commercially produced and is a functional, high-value, health food. We identified 5 low temperature and low light intensity tolerant strains of Arthrospira sp. (GMPA1, GMPA7, GMPB1, GMPC1, and GMPC3) using ethyl methanesulfonate mutagenesis and low temperature screening. The 5 Arthrospira strains grew rapidly below 14?°C, 43.75 μmol photons m^?2 s^?1 and performed breed conservation at 2.5?°C, 8.75 μmol photons m^?2 s^?1. We used morphological identification and molecular genetic analysis to identify GMPA1, GMPA7, GMPB1 and GMPC1 as Arthrospira platensis, while GMPC3 was identified as Arthrospira maxima. Growth at different culture temperatures was determined at regular intervals using dry biomass. At 16?°C and 43.75 μmol photons m^?2 s^?1, the maximum dry biomass production and the mean dry biomass productivity of GMPA1, GMPB1, and GMPC1 were 2057?±?80 mg l^?1, 68.7?±?2.5 mg l^?1 day^?1, 1839?±?44 mg l^?1, 60.6?±?1.8 mg l^?1 day^?1, and 2113?±?64 mg l^?1, 77.7?±?2.5 mg l^?1 day^?1 respectively. GMPB1 was chosen for additional low temperature tolerance studies and growth temperature preference. In winter, GMPB1 grew well at mean temperatures <10?°C, achieving 3258 mg dry biomass from a starting 68 mg. In summer, GMPB1 grew rapidly at mean temperatures more than 28?°C, achieving 1140 mg l^?1 dry biomass from a starting 240 mg. Phytonutrient analysis of GMPB1 showed high levels of C-phycocyanin and carotenoids. Arthrospira metabolism relates to terpenoids, and the methyl-d-erythritol 4-phosphate pathway is the only terpenoid biosynthetic pathway in Cyanobacteria. The 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) gene from GMPB1 was cloned and phylogenetic analysis showed that GMPB1 is closest to the Cyanobacterium Oscillatoria nigro-viridis PCC711. Low temperature tolerant Arthrospira strains could broaden the areas suitable for cultivation, extend the seasonal cultivation time, and lower production costs.     

Increased production of plumbagin in <Emphasis Type="Italic">Plumbago indica</Emphasis> root cultures by biotic and abiotic elicitors

Objectives

To evaluate the effects of 12 biotic and abiotic elicitors for increasing the production of plumbagin in Plumbago indica root cultures.

Results

Most elicitors showed minimal effects on the root dry weight, except for 250 mg chitosan l^?1 and 10 mM l-alanine that markedly decreased root biomass by about 40 % compared to the untreated root cultures (5 g l^?1). Treatments with 100 µM AgNO₃ significantly increased intracellular plumbagin production by up to 7.6 mg g^?1 DW that was 4-fold more than the untreated root cultures (1.9 mg g^?1 DW). In contrast, treatments with 150 mg chitosan l^?1, 5 mM l-alanine, and 50 µM 1-naphthol significantly enhanced the extracellular secretion of plumbagin by up to 10.6, 6.9, and 5.7 mg g^?1 DW, respectively, and increased the overall production of plumbagin by up to 12.5, 12.5, and 9.4 mg g^?1 DW, respectively.

Conclusions

Chitosan (150 mg l^?1), l-alanine (5 mM), and 1-naphthol (50 µM) were the best elicitors to enhance plumbagin production in P. indica root cultures.

     

Variations in the chemical composition of Costaria costata during harvest

In this study, variations in the chemical composition of Costaria costata collected during 3 months of the harvest period were analyzed. Moisture (4.94–10.50 %), ash (29.25–38.19 %), protein (9.77–18.15 %), lipid (0.60–2.21 %), crude fiber (4.45–5.68 %), alginate (22.49–29.13 %), fucoxanthin (0.07–0.32 mg g^?1), polyphenol (1.579–4.796 mg g^?1) were analyzed from dried alga. Six mineral elements were analyzed and the most abundant were calcium (6.64–11.56 mg g^?1) and magnesium (7.02–7.92 mg g^?1). Analysis of fatty acid composition indicated that the polyunsaturated fatty acids palmitoleic acid and linoleic acid were abundant in May and June, whereas the saturated fatty acid palmitic acid was abundant in July. Amino acid composition was also analyzed and the most abundant amino acids were aspartic acid, glutamic acid, glycine, and alanine. The ratio of mannuronic acid to guluronic acid of alginate was 2.57, 2.17, and 1.66 in May, June, and July, respectively. The gel strength of alginate was 1,449.0, 1,935.0, and 980.5 g cm^?1 in May, June, and July, respectively. The results of this study indicate that C. costata is an excellent resource that provides extensively applications in the industrial areas of chemicals, food, cosmetics, and pharmacy.     

Aboveground,belowground biomass and nutrients pool in <Emphasis Type="Italic">Salicornia brachiata</Emphasis> at coastal area of India: interactive effects of soil characteristics

The present study determined the plant biomass (aboveground and belowground) of Salicornia brachiata from six different salt marshes distributed in Indian coastal area over one growing season (September 2014–May 2015). The nutrients concentration and their pools were estimated in plant as well as soil. Belowground biomass in S. brachiata was usually lower than the aboveground biomass. Averaged over different locations, highest biomass was observed in the month of March (2.1 t ha^?1) followed by May (1.64 t ha^?1), February (1.60 t ha^?1), November (0.82 t ha^?1) and September (0.05 t ha^?1). The averaged aboveground to belowground ratio was 12.0. Aboveground and belowground biomass were negatively correlated with pH of soil, while positively with soil electrical conductivity. Further, there were positive relationships between organic carbon and belowground biomass; and available sodium and aboveground biomass. The nutrient pools in aboveground were always higher than to belowground biomass. Aboveground pools of carbon (543 kg ha^?1), nitrogen (48 kg ha^?1), phosphorus (4 kg ha^?1), sodium (334 kg ha^?1) and potassium (37 kg ha^?1) were maximum in the month of March 2015. Bioaccumulation and translocation factors for sodium of S. brachiata were more than one showing tolerance to salinity and capability of phytoremediation for the saline soil.     

Determination of resistance to low temperatures of winter buds on lateral shoot present in Karaerik (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.) grape cultivar

This study aims to determine the low temperature resistance of dormant buds at nodes with or without lateral shoots of Karaerik grape cultivar, and explain the relationship between the resistance and biochemical parameters in this grape cultivar. In this study, the mean values of high temperature exotherms (HTEs), low temperature exotherms (LTEs), water, reducing sugar, total soluble protein contents and antioxidant enzyme activities of dormant buds taken from nodes with or without lateral shoots were determined. The experiment has been found that buds in nodes with lateral shoots showed HTE and LTE at higher temperatures (HTE average ?6.7 °C and LTE average ?8.3 °C) than buds (HTE average ?7.9 °C and LTE average ?11.5 °C) in nodes without lateral shoots; therefore, buds in nodes with lateral shoots had less tolerance to low temperature. Additionally, lower sugar (average 41.05 mg g^?1), protein (average 1.61 mg g^?1), superoxide dismutase (average 425.27 EU g^?1 tissue), peroxidase (average 2516.1 EU g^?1 tissue) and polyphenol oxidase (average 7283.1 EU g^?1 tissue) were determined for buds taken from nodes with lateral shoots. Due to the fact that dormant buds taken from nodes with lateral shoots decreased the resistance to low temperatures, this research suggests that these lateral shoots should be excised with the summer pruning at the regions, where low temperatures caused the damages.     

Nutritional value of some algae from the north-western Mediterranean coast of Egypt

Fourteen taxa from Chlorophyta, Rhodophyta and Phaeophyta were collected from seven stations at different depths, along the north-western Mediterranean coast of Egypt during winter and summer 2006. Total carbohydrates (TCH), total protein (TPr), total lipids (TL), chlorophyll a, β-carotene, minerals and trace metals were determined in a total of 50 specimens. The concentrations of these components varied significantly with respect to the algal taxa and showed different patterns of distribution in the three classes. The content of TCH ranged from 5 to 20.9?%, being much higher for Cystoseira spinosa (20.9?%), TPr 3.86 to 27.65?% where Gelidium corneum showed the maximum value and TL content displayed wide variation (2.34 to 48.95?%), with Sargassum hornschuchii having the highest values. A minor component was β-carotene in all samples (1.80?2.50?×?10^?3 mg (100 g)^?1) which was much lower than in vegetables, in contrast to chlorophyll a concentrations which have attained high values (6.70?94.20 mg (100 g)^?1) and were lower than in vegetables. Mineral content was abundant in all samples and was higher than in common food and vegetables, whereas the measured trace metals all exceeded the permissible doses and were far from the accepted concentrations in the regulations of many countries. This limits their use in food consumption, except copper which recorded acceptable concentrations in the study. The maximum values of phosphorus (3,305 mg (100 g^?1), potassium (930 mg (100 g^?1) and calcium (3,070 mg (100 g^?1) were recorded in members of Chlorophyceae: Codium bursa, Udotea sp. and Udotea petiolata, whereas the red alga Rhodymenia ardissonei had the lowest concentrations in iodine (80 ppm) and sodium (1,450 mg (100 g)^?1) and the highest concentrations in the trace metals copper (3.89 ppm), nickel (13.14 ppm), zinc (38.87 ppm) and a relatively large amount of lead (41.60 ppm).     

DETERMINATION OF METHYLENE BLUE BIOSORPTION BY Rhizopus arrhizus IN THE PRESENCE OF SURFACTANTS WITH DIFFERENT CHEMICAL STRUCTURES

Methylene blue (MB) biosorption properties of Rhizopus arrhizus were investigated in the presence of surfactants. The effects of cationic and anionic surfactants on MB removal by dead biomass (1 g L^?1) were determined. MB removal was tested as a function of initial pH (2–12), contact time (5–1440 min), and dye (37.4–944.7 mg L^?1) and surfactant (0–10 mM) concentrations. The opposite charged anionic surfactant dodecylbenzenesulfonic acid sodium salt (DBS) enhanced sorption of cationic MB by biomass dramatically. Maximum biosorption capacity was 471.5 mg g^?1 at pH 8 with 0.5 mM DBS at 944.7 mg L^?1 MB concentration. The surfactant-stimulated fungal decolorization method may provide a highly efficient, inexpensive, and time-saving procedure in biological wastewater treatment technologies.     

Enhanced biological denitrification of high concentration of nitrite with supplementary carbon source

Nitrite accumulates during biological denitrification processes when carbon sources are insufficient. Acetate, methanol, and ethanol were investigated as supplementary carbon sources in the nitrite denitrification process using biogranules. Without supplementary external electron donors (control), the biogranules degraded 200 mg l^?1 nitrite at a rate of 0.27 mg NO₂–N g^?1?VSS h^?1. Notably, 1,500 mg l^?1 acetate and 700 mg l^?1 methanol or ethanol enhanced denitrification rates for 200 mg l^?1 nitrite at 2.07, 1.20, and 1.60 mg NO₂–N g^?1?VSS h^?1, respectively; these rates were significantly higher than that of the control. The sodium dodecyl sulfate polyacrylamide gel electrophoresis of the nitrite reductase (NiR) enzyme identified three prominent bands with molecular weights of 37–41 kDa. A linear correlation existed between incremental denitrification rates and incremental activity of the NiR enzyme. The NiR enzyme activity was enhanced by the supplementary carbon sources, thereby increasing the nitrite denitrification rate. The capacity of supplementary carbon source on enhancing NiR enzyme activity follows: methanol?>?acetate?>?ethanol on molar basis or acetate?>?ethanol?>?methanol on an added weight basis.     

Enhanced production of isoflavones by elicitation in hairy root cultures of Soybean

A combined treatment of sonication (2 min) and vacuum infiltration (2 min) stimulated isoflavones production of 75.26 mg g^?1 DW which was 15.11-fold higher than control hairy root line at optimal harvest time of 40 days. Addition of MeJ at 100 μM concentration with 72 h exposure time on 30 day-old hairy root culture further enhanced total isoflavones production of 53.16 mg g^?1 DW (10.67-fold) and SA at 200 μM concentration with 96 h exposure period enhanced the production of isoflavones (28.79 mg g^?1 DW; 5.78-fold). MeJ-treated hairy roots reduced biomass accumulation whereas sonication, vacuum infiltration and SA did not exhibit a negative effect on biomass growth.     

Modulation of antioxidant enzymes in <Emphasis Type="Italic">Juniperus procera</Emphasis> needles in relation to habitat environment and dieback incidence

Key message

Oxidative stress and the antioxidant enzymes’ activity are higher in damaged than in healthy Juniperus procera trees, in summer than in winter, and in dry than in wet condition.

Abstract

Many of the small stands of Juniperus procera in Saudi Arabia, confined mainly to Aseer Mountains in the southern part of the country, are suffering from branch dieback. As a part of the project on the structural and functional responses of healthy and dieback-affected trees to local environmental conditions of Al-Ghalab, Al-Yazeed, and Saodah locations, this study quantifies the oxidative stress generated and the consequent modulation of proline accumulation and antioxidant enzymes’ activity, as determined by chemical analysis of needle tissues from samples collected in summer and winter seasons. The level of TBARS, which indicated the extent of oxidative stress, was minimum (10.1 nM g^?1 f w) at Al-Ghalab and maximum (28.1 nM g^?1 f w) at Al-Yazeed, being relatively higher in summer than in winter. Healthy trees had a lower level of TBARS than those suffering from dieback. Proline content showed 147–54 µg g^?1 in healthy trees and 460–99 µg g^?1 f w in affected ones. Variation in the activity of superoxide dismutase, ascorbate peroxidase, glutathione reductase, and catalase was around 0.7–3.6, 0.01–0.09, 0.02–0.08, and 0.6–3.0 U mg^?1 min^?1, respectively, in healthy trees, whereas 2.3–6.1, 0.04–0.3, 0.04–0.3, and 2–5.8 U mg^?1 min^?1, respectively, in the dieback-affected trees of the different locations. Thus, the oxidative stress and the enzymatic stimulation were higher in damaged than in healthy trees and in summer than in winter season. Water-harvesting efforts at the collection sites showed ameliorative effects. Our observations suggest that J. procera tree can be made more tolerant toward stressful condition, and even the risk of dieback can be avoided or minimized by improving soil–water availability through adequate water-harvesting strategies in the drought-affected areas.